Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 12/23/15
AREA FORECAST DISCUSSION
NWS RENO NV
943 PM PST SUN DEC 20 2015
.UPDATE...
BUOYS AT LAKE TAHOE ARE SHOWING A DECREASE IN WIND SPEEDS LATE
THIS EVENING A LITTLE FASTER THAN ORIGINALLY FORECAST. THIS COULD
BE IN RESPONSE TO PRECIPITATION MAKING ITS WAY INTO THE TAHOE
BASIN DAMPENING THE WINDS. THINK THIS WILL BE THE CASE THROUGH THE
REMAINDER OF THE NIGHT BEFORE INCREASING PRESSURE/THERMAL GRADIENT
STARTS TO INCREASE THE WINDS AGAIN MONDAY. THUS...WE WILL CANCEL
THE LAKE WIND ADVISORY FOR LAKE TAHOE A LITTLE EARLY TONIGHT.
ELSEWHERE...LIGHT SNOW CONTINUES FOR THE TAHOE BASIN NORTH INTO
PARTS OF SIERRA AND PLUMAS COUNTIES. THIS PRECIPITATION IS NOT
HEAVY BUT HAS BEEN CAUSING TRAVEL PROBLEMS IN PARTS OF THE TAHOE
BASIN...ESPECIALLY INTERSTATE 80. THIS IS JUST THE PRECURSOR TO A
MUCH MORE SUBSTANTIAL PUSH OF MOISTURE INTO THE REGION MONDAY
THROUGH TUESDAY. ADJUSTMENTS WILL LIKELY BE NEEDED TO FORECASTS
OVER THE NEXT 36 HOURS...BUT FOR NOW WE WILL MAKE NO SIGNIFICANT
CHANGES TO THE NEXT 12 HOURS OUTSIDE OF THE WINDS. 20
&&
.PREVIOUS DISCUSSION... /ISSUED 351 PM PST SUN DEC 20 2015/
SYNOPSIS...
ACTIVE WINTER PATTERN CONTINUES THROUGH THE END OF THE WEEK. EACH
STORM WILL BRING SNOW, WIND, AND THE POTENTIAL FOR TRAVEL
HEADACHES. THE MAIN PERIODS OF CONCERN WILL BE MONDAY INTO TUESDAY
AND CHRISTMAS EVE INTO CHRISTMAS DAY. AT THIS POINT IT APPEARS
THAT WEDNESDAY WILL BE THE BEST TRAVEL DAY IF YOUR PLANS INCLUDE
CROSSING THE SIERRA.
SHORT TERM...
THERE HAVE BEEN SIGNIFICANT CHANGES EARLY THIS WEEK AS MODELS HAVE
BECOME EXTREMELY WET FROM MONDAY THROUGH TUESDAY AFTERNOON.
MOISTURE FLUX OFF THE PACIFIC HAS INCREASED SEVERAL FOLD WITH AN
ANOMALOUS STREAM SLAMMING INTO THE SIERRA FOR 12-24 HOURS. THIS
HAS CORRELATED TO A LARGE INCREASE IN FORECAST SNOW TOTALS FROM
WESTERN LASSEN COUNTY SOUTH THROUGH MONO COUNTY. WINTER STORM
WARNINGS HAVE BEEN ISSUED GENERALLY STARTING MONDAY MORNING AND
CONTINUING THROUGH TUESDAY MORNING FROM LASSEN COUNTY THROUGH THE
TAHOE BASIN. A WINTER WEATHER ADVISORY HAS BEEN ISSUED FOR MONO
COUNTY WITH FROM LATE MONDAY MORNING THROUGH TUESDAY AFTERNOON.
..PRECIPITATION...
A BROAD 1-1.5 INCH PWAT PLUME WILL STREAM INTO THE REGION EARLY
MONDAY AND PERSIST THROUGH TUESDAY AFTERNOON. THIS WILL ALLOW FOR
AN EXTENDED PERIOD OF SNOW TO FALL MAINLY IN THE SIERRA AND
NORTHERN ZONES NEAR THE OREGON BORDER. SNOW LEVELS WILL START LOW
AROUND 5000-5500 FT BEFORE RISING TO AROUND 7000 FT THROUGH
TUESDAY MORNING. THE RESULT WILL BE COPIOUS SNOWFALL ABOVE 7000
FEET IN THE SIERRA SERIOUSLY IMPACTING TRAVEL OVER AREA PASSES.
ALL SAID AND DONE...THERE COULD BE 2-3 FEET ABOVE 7000 FEET IN THE
TAHOE BASIN.
THERE IS A LOT OF UNCERTAINTY BELOW 7000 FEET ESPECIALLY IN THE
TAHOE BASIN AND AROUND TRUCKEE. SINCE SNOW LEVELS START FAIRLY
LOW, THERMAL PROFILES WILL LIKELY GO ISOTHERMAL WITH SNOW MELT
DELAYING THE LIFTING OF SNOW LEVELS. THEREFORE, 4 TO 8 INCHES OF
HEAVY WET SNOW WILL BE POSSIBLE DOWN TO LAKE LEVEL. HOWEVER, IF
SNOW RATES DECREASE, SNOW LEVELS WILL RISE MORE RAPIDLY AND SNOW
WILL SWITCH TO RAIN.
SIMILARLY, LASSEN AND PLUMAS WILL SEE AN INFLUX OF MOISTURE. SNOW
TOTALS HAVE INCREASE MAINLY WEST OF HIGHWAY 395 ABOVE 5500 FT - 8
TO 14 INCHES POSSIBLE. LOWER TOTALS ARE EXPECTED EAST OF HIGHWAY
395 AND MORE SEQUESTERED TO NORTHERN LASSEN COUNTY - 4 TO 8 INCHES
POSSIBLE.
DUE TO SHADOWING, ACCUMULATIONS WILL BE LOWER FOR MONO COUNTY.
GENERALLY EXPECTING 6 TO 18 INCHES MAINLY WEST OF HIGHWAY 395 AND
ABOVE 7500 FEET. THE HIGHEST TOTALS WILL BE AROUND MAMMOTH
MOUNTAIN AND THE HIGHER SIERRA.
WESTERN NEVADA WILL BE LARGELY SHADOWED AND LITTLE SNOW
ACCUMULATION IS LIKELY. LOCATIONS DOWN TO 5500 FEET COULD SEE AN
INCH OR TWO, BUT THE CHARACTER WILL BE WET AND LESS LIKELY TO
CAUSE WIDESPREAD TRAVEL CONCERNS. EXPECT RAIN BELOW 5500 FEET.
STILL EXPECTING CONSISTENT ACCUMULATIONS FOR THE SURPRISE VALLEY
AND NORTHERN WASHOE COUNTY. 2 TO 6 INCHES WILL BE MOST LIKELY
WITH ABOUT A 25% CHANCE OF HIGHER TOTALS UP TO 8 INCHES.
PRECIPITATION WILL TAPER OFF TUESDAY AFTERNOON WITH PRIMARY
MOISTURE SHIFTING SOUTH. SNOW LEVELS WILL DROP AS FLOW ALOFT TURNS
MORE NORTHERLY AND LINGERING SCATTERED SNOW SHOWERS CAN BE
EXPECTED FOR THE SIERRA FROM THE TAHOE BASIN TO THE OREGON BORDER.
..WINDS...
IT IS BREEZY AROUND THE REGION TODAY WITH GUSTS 20-35 MPH FOR
VALLEYS/SLOPES AND 45-60 MPH FOR NORTHERN SIERRA RIDGES AND THE
HIGHER PEAKS OF FAR WESTERN NEVADA. THERE IS A LAKE WIND ADVISORY IN
PLACE FOR LAKE TAHOE THROUGH EVENING. WINDS HAVE INCREASED TO 10-20
MPH ON THE LAKE PER BUOYS. WITH WINDS INCREASING OVER THE TAHOE
CREST AND THE 22Z HRRR INDICATES HIGHER WINDS FOR LATE THIS
AFTERNOON AND EARLY EVENING ON THE LAKE, WINDS MAY RAMP UP A BIT
MORE SHORTLY.
MOVING ON TO TOMORROW, WINDS ALOFT WILL INCREASE WITH 700 MB WINDS
OF 50-75 KTS IN THE NAM IN THE AFTERNOON. NAM CROSS-SECTIONS HINT AT
SOME DOWNSLOPING WINDS MONDAY AFTERNOON IN THE LEE OF THE CARSON
RANGE AND WINDS ALOFT DO NOT INCREASE ABOVE 700 MB SO SHADOWING
SHOULD BE STRONG. WITH ALL THIS IN MIND, WE EXPECT WINDS GUSTING TO
65-70 MPH IN THE FOOTHILLS WITH WIDESPREAD GUSTS 40-55 MPH. STRONG
WINDS MAY EXTEND OUT TO ALONG HIGHWAY 50 IN CHURCHILL COUNTY FROM
ABOUT FALLON WESTWARD, AND SOUTH ALONG HIGHWAY 395 TO ABOUT
BRIDGEPORT.
FOR THE TAHOE BASIN, NORTHEAST CALIFORNIA AND FAR NORTHWEST NEVADA,
INCREASING PRECIPITATION MONDAY AFTERNOON IS EXPECTED TO STABILIZE
THE ATMOSPHERE ENOUGH TO HOLD WINDS DOWN CONSIDERABLY. HOWEVER, IT
WILL STILL BE RATHER BREEZY GIVEN A RESPECTABLE SURFACE GRADIENT
(SUB-990 MB MSLP LOW ALONG THE OREGON-WASHINGTON BORDER), ESPECIALLY
DURING PERIODS OF SLACKENED PRECIPITATION.
TUESDAY, WINDS SHOULD RELAX CONSIDERABLY ALTHOUGH IT WILL REMAIN
BREEZY. SNYDER
LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY...
CONFIDENCE CONTINUES TO INCREASE FOR AN ALL SNOW EVENT STARTING LATE
WEDNESDAY NIGHT FOR NORTHEAST CA TO THE SIERRA CREST WEST OF TAHOE,
AND SPREADING ACROSS THE REMAINDER OF THE REGION ON THURSDAY. SNOW
AMOUNTS WILL NOT BE EXCESSIVE DUE TO THE FAST MOVEMENT OF THIS STORM
SYSTEM, BUT LATEST GUIDANCE IS HINTING AT UNSTABLE CONDITIONS
ALLOWING FOR BANDS OF SNOW TO EFFICIENTLY SPREAD ACROSS WESTERN NV,
WITH ACCUMULATIONS MORE LIKELY EVEN IN LOWER VALLEYS OF WEST CENTRAL
NV. SNOWFALL RATES WILL ALSO BE SIGNIFICANT, WITH UP TO 2 INCHES PER
HOUR AT TIMES. THE BEST RECOMMENDATION FOR CHRISTMAS HOLIDAY TRAVEL
IN THE SIERRA AND WESTERN NV IS TO COMPLETE THE TRIP ON WEDNESDAY IF
POSSIBLE.
EARLY SNOWFALL PROJECTIONS FOR EASTERN CA REMAIN SIMILAR TO OUR
THINKING FROM YESTERDAY, AS AREAS WEST OF TAHOE TO THE SIERRA CREST
MAY RECEIVE OVER 1 FOOT OF SNOWFALL. AT LEAST 6 INCHES OF SNOW ARE
POSSIBLE FROM NORTHEAST CA TO MONO COUNTY WEST OF HIGHWAY 395,
INCLUDING THE TAHOE BASIN. THE MAIN ADJUSTMENT WAS FOR THE
SUSANVILLE-RENO-CARSON CITY VICINITY WHERE WE COULD RECEIVE 3-6
INCHES, WITH A COUPLE OF INCHES POSSIBLE EAST TO THE HIGHWAY 95
CORRIDOR.
BY LATE THURSDAY, THE STEADY SNOW WILL QUICKLY WIND DOWN ACROSS THE
REGION, WITH SOME BANDS OF SNOW SHOWERS LINGERING MAINLY SOUTH OF
SUSANVILLE-FALLON INTO THE EVENING.
ANY SNOW THAT FALLS THURSDAY NIGHT WILL STICK AROUND FOR CHRISTMAS
DAY AND NEXT WEEKEND AS COLD CONDITIONS WILL PREVAIL. HIGHS ARE ONLY
EXPECTED TO REACH THE LOWER 30S IN LOWER ELEVATIONS AND 20S NEAR THE
SIERRA. THERE IS LOWER POTENTIAL FOR A SECONDARY SHORTWAVE BRINGING
MORE ORGANIZED AREAS OF SNOW TO THE REGION, BUT FLURRIES AND LIGHT
SNOW SHOWERS WILL REMAIN POSSIBLE THROUGH THE DAY.
FOR NEXT WEEKEND, DRY CONDITIONS ARE EXPECTED AS RIDGE BUILDS OVER
THE REGION WITH CLEAR TO PARTLY CLOUDY SKIES. CHILLY TEMPERATURES
WILL CONTINUE WITH LOWS DROPPING TO THE SINGLE DIGITS AND LOWER
TEENS BOTH FRIDAY AND SATURDAY NIGHTS, WITH EVEN COLDER TEMPS NEAR
OR BELOW ZERO POSSIBLE IN LOWER VALLEYS IF SNOW COVER IS PRESENT.
HIGHS BOTH SATURDAY AND SUNDAY WILL REMAIN BELOW NORMAL IN THE 20S
AND 30S, WITH VALLEY INVERSIONS LIKELY. A SHORT PERIOD OF STRONGER
NORTH TO NORTHEAST RIDGE WINDS REMAINS POSSIBLE ACROSS THE SIERRA
FRIDAY NIGHT INTO SATURDAY MORNING. MJD
AVIATION...
MULTIPLE WEATHER RELATED IMPACTS FOR AVIATION ARE EXPECTED THROUGH
TUESDAY. FOR MONDAY, THE PRIMARY IMPACTS WILL BE INCREASED WINDS
WITH GUSTS 35-45 KT AT MOST TERMINALS, AND SIERRA RIDGE GUSTS 70-85
KT. THE STRONG RIDGE GUSTS WILL CONTINUE INTO TUESDAY, WITH ONLY A
SLIGHT DECREASE IN WIND SPEEDS FOR LOWER ELEVATIONS. THESE WINDS
WILL PRODUCE TURBULENT FLYING CONDITIONS ACROSS THE SIERRA AND
WESTERN NV.
LIGHT SNOW SHOWERS WILL BE POSSIBLE AT THE SIERRA TERMINALS MONDAY,
WITH A HIGHER POTENTIAL FOR SNOW ACCUMULATIONS ON RUNWAYS ALONG WITH
IFR OR WORSE CIGS/VSBY MONDAY NIGHT INTO TUESDAY. FOR WESTERN NV,
ISOLATED -SHRA ARE POSSIBLE MONDAY, WITH SOME INCREASE IN SHOWER
POTENTIAL BY TUESDAY. WHILE CIGS/VSBY WILL GENERALLY REMAIN IN THE
VFR CATEGORY FOR KRNO-KCXP (EXCEPT MVFR AT TIMES IN HEAVIER SHOWERS)
MOUNTAIN OBSCURATIONS ARE LIKELY TO PERSIST FOR MUCH OF MONDAY AND
TUESDAY. ICING WILL GENERALLY BE MIXED WITH HIGHEST ACCRETION
FROM THE SURFACE TO AROUND 14000 FT MSL. MJD
&&
.REV WATCHES/WARNINGS/ADVISORIES...
NV...WINTER WEATHER ADVISORY FROM 10 AM MONDAY TO 4 AM PST TUESDAY
NVZ005.
WINTER STORM WARNING FROM 10 AM MONDAY TO 10 AM PST TUESDAY
NVZ002.
WIND ADVISORY FROM 9 AM TO 10 PM PST MONDAY NVZ003.
LAKE WIND ADVISORY FROM 9 AM TO 5 PM PST MONDAY FOR PYRAMID LAKE
IN NVZ004.
CA...WINTER STORM WARNING FROM 4 AM MONDAY TO 4 AM PST TUESDAY ABOVE
5500 FEET FOR CAZ071.
WINTER WEATHER ADVISORY FROM 10 AM MONDAY TO 4 AM PST TUESDAY
CAZ070.
WINTER WEATHER ADVISORY FROM 10 AM MONDAY TO 4 PM PST TUESDAY
CAZ073.
WINTER STORM WARNING FROM 10 AM MONDAY TO 10 AM PST TUESDAY
CAZ072.
&&
$$
FOR MORE INFORMATION FROM THE NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/RENO (ALL LOWER CASE)
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
910 PM EST TUE DEC 22 2015
.UPDATE...
01Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS A BROAD UPPER TROUGH
IN PLACE OVER MUCH OF THE CONUS FROM THE PACIFIC COAST TO THE MS
VALLEY. WEAK RIDGING EXISTS OVER THE WESTERN ATLANTIC...AND WILL
BE EXPANDING WESTWARD TO INFLUENCE OUR LOCAL WEATHER MORE AND MORE
THROUGH THE MIDDLE PORTION OF THE WEEK. AT THE SURFACE...OUR
REGION LIES WITHIN A BROAD MOIST SOUTHERLY FLOW REGIME AROUND THE
WESTERN PERIPHERY OF RIDGING OVER THE WESTERN ATLANTIC. THE
CONTINUED SOUTHERLY FLOW IS BRINGING ABUNDANT LOW LEVEL MOISTURE
AND RATHER HUMID CONDITIONS FOR DECEMBER. WHILE A FEW SHOWERS
DEVELOPED OVER THE FLORIDA PENINSULA THIS PAST AFTERNOON...IT WAS
A WASHOUT...WITH WIDESPREAD RAIN...JUST TO THE NORTHWEST OF OUR
ZONES ACROSS THE BIG BEND AND FLORIDA PANHANDLE.
TODAY WAS ABOUT THE CLOSEST THAT THIS MORE ORGANIZED RAIN WAS
GOING TO COME TO OUR AREA. WITH THE UPPER RIDGE STRENGTHENING
OVERHEAD THE NEXT COUPLE OF DAYS...WE CAN EXPECT ANY SIGNIFICANT
RAIN TO REMAIN OFF TO OUR NORTH AND NORTHWEST.
WHILE NO ORGANIZED RAINFALL IS EXPECTED...THE FORECAST REMAINS
UNSEASONABLY WARM. SEE LITTLE REASON NOT TO ANTICIPATE
TEMPERATURES INTO THE LOWER/MIDDLE 80S AWAY FROM THE BEACHES
THROUGH THE NEXT SEVERAL DAYS (AT LEAST).
THE FORECAST IS GOING TO BECOME A "BROKEN RECORD" THROUGH THE
REMAINDER OF THE WEEK. WELL ABOVE NORMAL TEMPERATURES...AND JUST A
SLIGHT CHANCE OF AN AFTERNOON INSTABILITY SHOWER EACH DAY.
&&
.AVIATION...
GENERAL VFR CONDITIONS ACROSS WEST-CENTRAL AND SOUTHWEST FLORIDA
THIS EVENING...ALTHOUGH PLENTY OF LOW LEVEL MOISTURE IN PLACE...
THE DEEPER INTO THE OVERNIGHT WE GET...THE POTENTIAL FOR AREAS OF
IFR/MVFR CIGS/VIS WILL BE INCREASING. HAVE ALL TERMINALS IN
PREVAILING MVFR AFTER 07-08Z...WITH ANY SPOT POSSIBLY SEEING A
PERIOD OF IFR RESTRICTIONS IN THE HOURS SURROUNDING SUNRISE. CIGS
SHOULD LIFT WEDNESDAY MORNING...WITH GENERAL VFR CONDITIONS AND
GUSTY SOUTHERLY WINDS DEVELOPING FOR LATE MORNING AND AFTERNOON.
&&
.MARINE...
HIGH PRESSURE OVER THE WESTERN ATLANTIC CONTINUES TO RIDGE
WESTWARD OVER THE FLORIDA PENINSULA AND EASTERN GULF THROUGH THE
END OF THE WEEK. SOUTHEASTERLY FLOW WILL PREVAIL...HOWEVER WITH
A FAIRLY WEAK GRADIENT ACROSS THE AREA...WINDS SHOULD GENERALLY
REMAIN BELOW 15 KNOTS. THIS PATTERN WILL LIKELY HOLD THROUGH THE
UPCOMING WEEKEND...WITH THE NEXT POTENTIAL COLD FRONT TO IMPACT
THE EASTERN GULF OF MEXICO NOT ARRIVING UNTIL THE EARLY PART OF
NEXT WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 71 82 69 84 / 20 10 10 10
FMY 71 85 71 86 / 20 10 10 10
GIF 70 85 70 85 / 40 10 10 10
SRQ 71 82 70 83 / 20 10 10 10
BKV 70 85 68 85 / 20 10 10 10
SPG 70 82 71 83 / 20 10 10 10
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
UPDATE/AVIATION/MARINE...14/MROCZKA
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
648 PM EST TUE DEC 22 2015
.SYNOPSIS...
UNSEASONABLY WARM AND MOIST AIR WILL AFFECT THE AREA WHILE A
SERIES OF UPPER LEVEL DISTURBANCES IMPACT THE SOUTHEAST THROUGH
MID WEEK. HIGH PRESSURE AND UNSEASONABLY WARM TEMPERATURES WILL
PREVAIL LATE WEEK THROUGH EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
A BAND OF LIGHT SHOWERS MOVING INTO SOUTHEAST GEORGIA EARLY THIS
EVENING APPEARS TO BE ALIGNED WITH A WEAK AREA MULTI-SURFACE
ISENTROPIC ASSENT. LATEST RAP OUTPUT SHOWS THIS AREA OF SHOWERS
PROPAGATING INTO SOUTHEAST SOUTH CAROLINA AND WEAKENING AS
ASSENT DIMINISHES AND WEAK ISENTROPIC DOWNGLIDE COMMENCES.
MODIFIED POPS TO ACCOUNT FOR CURRENT RADAR TRENDS WITH POPS
50-70 PERCENT PREVAILING FOR THE NEXT FEW HOURS.
HIGH RESOLUTION GUIDANCE KEEPS THE BULK OF ANY ADDITIONAL
ISENTROPIC ASSENT DISPLACED TO THE WEST CLOSER TO THE DECAYING
WARM FRONT THAT EXTENDS ACROSS CENTRAL GEORGIA...THROUGH THE CSRA
TO NEAR COLUMBIA. THIS IS WHERE THE BETTER CHANCES FOR MEASURABLE
RAIN WILL GRADUALLY TRANSITION. INDEED...THE LATEST MRMS RALAS
PRODUCT SHOWS SHOWER ACTIVITY OVER NORTHERN FLORIDA GRADUALLY
WEAKENING WHERE ISENTROPIC DOWNGLIDE IS ALREADY OCCURRING. THIS
LEADS TO LOWER CONFIDENCE ON EXACTLY HOW MUCH MEASURABLE RAIN WILL
OCCUR OVERNIGHT ACROSS SOUTHEAST SOUTH CAROLINA AND SOUTHEAST
GEORGIA. POPS AND QPF HAVE BEEN LOWERED FROM MIDNIGHT ON TO
ACCOUNT FOR DRIER TRENDS NOTED IN BOTH THE H3R AND RAP. IT WILL
REMAIN A WARM AND HUMID NIGHT WITH LOWS IN THE LOWER-MID 60S.
CONCERNS SHIFTS TO SEA FOG AND FOG DEVELOPING FROM STATUS BUILD-
DOWN. THE PATTERN APPEARS TO FAVOR A WIDESPREAD STRATUS BUILD-DOWN
EVENT AS RAIN DIMINISHES AND WEAK LOW-LEVEL JETTING ENSUES.
ALREADY SEEING A NUMBER OF INLAND STATIONS REPORTING CEILINGS LESS
THAN 1000 FT WHICH INDICATES BUILD-DOWN IS ALREADY IN PROGRESS.
THE RAIN MOVING ACROSS SOUTHEAST GEORGIA COULD DELAY ANY
ADDITIONAL CLOUD LOWERING THERE FOR A FEW MORE HOURS...BUT SHOULD
RESTART BY LATE EVENING. THIS WILL EVENTUALLY TRANSLATE TO AREAS
OF FOG AND POSSIBLY SOME LIGHT DRIZZLE...BUT VSBYS MAY NOT GO MUCH
BELOW 1-2 MILES GIVEN THE DEGREE OF LOW-LEVEL JETTING IN PLACE.
CLOSER TO THE COAST...SEA FOG WAS ALREADY PREVALENT OVER THE
COASTAL WATERS AND AS WINDS TURN BACK TO THE SOUTH OVER THE NEXT
FEW HOURS...THE COMBINATION OF SEA FOG MOVING INLAND AND STRATUS
BUILD-DOWN COULD BE JUST ENOUGH TO TIP VSBYS BELOW 1 MILE. A DENSE
FOG ADVISORY MAY VERY WELL BE NEEDED IN SOME AREAS BEFORE SUNRISE
WEDNESDAY AND TRENDS ARE BEING MONITORED CLOSELY.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
WEDNESDAY THROUGH WEDNESDAY NIGHT...THE AREA REMAINS FIRMLY
ENTRENCHED WITHIN A DEEP AND RICH SOUTH/SE FLOW THROUGHOUT THE
ENTIRE VERTICAL COLUMN...IN THE ZONE BETWEEN STRONG SUB-TROPICAL
RIDGING TO THE EAST/SE BOTH SURFACE AND ALOFT...AND A DEEP CYCLONE
AND FRONTAL SYSTEM OVER THE CENTRAL/NORTHERN PLAINS THAT LIFTS
INTO SOUTHERN CANADA. THE TAP OF COPIOUS AMOUNTS OF MOISTURE WILL
CONTINUE TO FEED INTO THE REGION FROM NOT ONLY THE GULF OF
MEXICO...BUT ALSO THE PACIFIC. ASSOCIATED PWATS OF 1.9-2.0 INCHES
IS CLOSE TO THE HIGHEST ON RECORD FOR THESE PARTS IN DECEMBER.
ALTHOUGH THE BEST FORCING AND DYNAMICS REMAIN OFF TO THE
WEST/NW...THE CLOSE PROXIMITY TO MID LEVEL IMPULSES AND UPPER
DIVERGENCE WILL COMBINE WITH AN ABUNDANTLY MOIST ATMOSPHERE TO
PRODUCE ANOTHER FAIRLY WET AND CLOUDY DAY. THE FLOW LOOKS A LITTLE
TOO FAST WITH A35-40 KT LOW LEVEL JET TRAVERSING THE AREA FOR ANY
SIGNIFICANT FLOODING CONCERNS. ALTHOUGH MINOR FLOODING MAY OCCUR
WITH SOME HEAVY DOWNPOURS AND FURTHER COMPLICATIONS AROUND THE
TIMES OF HIGH TIDE IN THE PRE-DAWN AND AGAIN IN THE EARLY EVENING.
MODEST SHEAR VALUES AND SOME CAPE SUPPORTS THE POTENTIAL FOR A
FEW T-STORMS. BUT POOR LAPSE RATES AND THE OVERCAST SKIES SUGGEST
THAT ANY SEVERE RISK IS CLOSE TO ZERO.
LAND-BASED FOG IN THE MORNING WILL LIFT BY 10 AM BUT LINGER NEAR
OR JUST OFF THE COAST THE REST OF THE DAY...BEFORE COMING BACK
AGAIN WEDNESDAY NIGHT. DENSE FOG ADVISORIES MIGHT BE
REQUIRED...ALTHOUGH THE WIND FIELDS WEDNESDAY NIGHT MIGHT BE A
LITTLE TOO STRONG.
TEMPS WILL REMAIN FAR ABOVE NORMAL...BELOW ANY RECORD HIGHS
WEDNESDAY BUT POSSIBLY NEAR RECORD HIGH MINIMUMS WEDNESDAY NIGHT.
THURSDAY THROUGH FRIDAY...DEEP RIDGING BOTH SURFACE AND ALOFT
WILL EXPAND WEST FROM THE ATLANTIC AS 500 MB HEIGHTS CLIMB TO NEAR
RECORD LEVELS FOR DECEMBER. WE MIGHT BE ABOVE 5900 METERS BOTH
DAYS AS 850 MB TEMPS REMAIN NEAR 2 OR 3 STANDARD DEVIATIONS ABOVE
NORMAL. COMBINED WITH LOW LEVEL THICKNESS APPROACHING 1400 METERS
WILL GENERATE YET ADDITIONAL WARMTH. AND AS INCREDIBLE AS IT
SOUNDS PARTS OF THE FORECAST DISTRICT CHRISTMAS EVE AND CHRISTMAS
DAY WILL REACH NEAR OR OVER 80F. THIS IS SOME 20F ABOVE WHAT IS
CONSIDERABLE NORMAL FOR THIS TIME OF YEAR. MORE SUBSIDENCE AND
LESS AVAILABLE MOISTURE POINTS TOWARDS LESS RISK FOR SHOWERS AND
T-STORMS. BUT THE POTENTIAL FOR FOG IS HIGH GIVEN LESS GEOSTROPHIC
WINDS...ELEVATED DEW POINTS...STRATUS BUILD-DOWN AND THE RISK FOR
SEA FOG. DENSE ADVISORIES SEEM A GOOD BET THURSDAY NIGHT INTO
FRIDAY MORNING.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
A DEEP LAYERED RIDGE WILL PREVAIL NEXT WEEKEND INTO EARLY NEXT
WEEK. WARM AND MOIST AIR WILL PERSIST WITH HIGH TEMPS APPROACHING
DAILY RECORDS AND DEWPOINTS WELL INTO THE 60S. A WEAK COASTAL
TROUGH MAY MOVE INLAND AT SOME POINT OVER THE WEEKEND SO WE HELD
ONTO SLIGHT CHANCE POPS AT TIMES. BUT THERE DO NOT LOOK TO BE ANY
SIGNIFICANT WEATHER SYSTEMS UNTIL EARLY TO MID NEXT WEEK WHEN A
FRONT APPROACHES.
&&
.AVIATION /23Z TUESDAY THROUGH SUNDAY/...
KCHS...IFR CIGS ARE ALREADY IN PLACE AT KCHS AND ARE EXPECTED TO
DROP BELOW ALTERNATE MINIMUMS 02-03Z. THE VSBY FORECAST IS NOT AS
CLEAR CUT...BUT VSBYS AS LOW AS 2-3SM ARE POSSIBLE...MAINLY AFTER
09Z. IF SEA FOG MOVES INLAND FROM THE ATLANTIC LIKE SOME GUIDANCE
SUGGESTS...THEN BOTH CIGS AND/OR VSBYS COULD DROP BELOW AIRFIELD
MINIMUMS. THIS IS NOT EXPECTED ATTM. CONDITIONS WILL IMPROVE BY
14Z...BUT MVFR CIGS WILL PREVAIL THROUGH THE PERIOD.
KSAV...LIGHT RAIN MOVING ACROSS THE TERMINAL WILL DELAY THE ONSET
OF IFR CIGS UNTIL AFTER 03Z...AFTER WHICH STRATUS BUILD-DOWN WILL
ENSUE. EXPECT CIGS TO DROP BELOW AIRFIELD MINIMUMS BY 08-09Z...BUT
THE TIMING OF THIS IS A LITTLE UNCERTAIN. IT COULD EASILY GET
THERE BEFORE THEN...BUT CONFIDENCE IS NOT HIGH ENOUGH ATTM TO MOVE
THIS FORWARD IN TIME. IT APPEARS BOTH VSBYS AND CIGS WILL REMAIN
ABOVE AIRFIELD MINIMUMS...BUT IT COULD BE CLOSE IF SOME SEA FOG
ADVECTS IN FROM OFF THE ATLANTIC. CONDITIONS WILL IMPROVE BY
14Z...BUT MVFR CIGS WILL PREVAIL THROUGH THE PERIOD.
EXTENDED AVIATION OUTLOOK...PROLONGED PERIODS OF MVFR OR LOWER
CONDITIONS WILL IMPACT THE TERMINALS MUCH OF THE TIME WEDNESDAY
AFTERNOON INTO SUNDAY...WITH THE WORST WEATHER OF IFR/LIFR TO
OCCUR AT NIGHT AND INTO THE MORNING HOURS IN DENSE FOG/STRATUS.
&&
.MARINE...
TONIGHT..VSBYS HAVE IMPROVED A BIT ACROSS THE WATERS WHERE WINDS
HAVE BACKED A BIT MORE TO THE SOUTHEAST. THIS HAS REDUCED PARCEL
RESIDENCE TIMES OVER THE CHILLY SHELF WATERS. EXPECT WINDS TO BACK
BACK TO THE SOUTH OVER THE NEXT FEW HOURS WHICH SHOULD SUPPORT A
REDEVELOPMENT OF DENSE SEA FOG. A MARINE DENSE FOG ADVISORY IS IN
EFFECT FOR ALL NEARSHORE LEGS THROUGH MIDNIGHT...BUT THIS MAY NEED
TO BE EXTENDED. SOME FOG HAS REACHED THE CHARLESTON HARBOR...AND
THE ADVISORY MAY VERY WELL NEED TO BE EXPANDED TO INCLUDE IT LATER
THIS EVENING.
OTHERWISE...WINDS WILL VEER SOUTH OVERNIGHT WITH WINDS 10 KT OR
SO NEARSHORE WATERS AND AS HIGH AS 15 KT OFFSHORE WATERS. SEAS
WILL AVERAGE 3-5 FT NEARSHORE AND 4-6 FT OFFSHORE.
WEDNESDAY THROUGH WEDNESDAY NIGHT...THE COASTAL WATERS WILL LIE
WITHIN THE WESTERN PERIPHERY OF AN EXPANDING REGION OF ATLANTIC
HIGH PRESSURE...AS AN INTENSE STORM SYSTEM PULLS RAPIDLY NORTH/NE
THROUGH THE GREAT PLAINS AND INTO SOUTHERN CANADA. WHILE MIXING IS
STRONGLY CURTAILED WITHIN THE WARM ADVECTION PATTERN...THE
GRADIENT FLOW IS STILL HIGH ENOUGH TO SUPPORT A LOW-END SMALL
CRAFT ADVISORY FOR AT LEAST AMZ350 AND AMZ374. A FEW 6-FOOTERS
COULD SLIDE INTO AMZ352...BUT THE COVERAGE IS FAR TOO LIMITED TO
HOIST AND ADVISORY AT THIS TIME. ALSO...WINDS MIGHT REACH CLOSE TO
25 KT FOR A FEW HOURS WEDNESDAY AFTERNOON INTO THE EVENING...BUT
PROBABILITIES ARE LOW ENOUGH WHERE WE DON/T NEED AN ADVISORY FOR
THEM EITHER.
THURSDAY THROUGH SUNDAY...A STRONG AND BROAD SUB-TROPICAL
ATLANTIC HIGH WILL BUILD WESTWARD ACROSS THE MARITIME COMMUNITY
RESULTING IN GENERAL SOUTH/SE WIND AT OR BELOW 15 KT. FOR THE MOST
PART SEAS WILL BE NO MORE THAN 3-5 FT...EXCEPT LINGERING 6-FOOTERS
ON THE OUTER GA WATERS THROUGH MUCH OF THURSDAY WHERE AN SCA
REMAINS IN EFFECT.
SEA FOG...CONDITIONS ARE FAVORABLE FOR A CONTINUATION OF SEA FOG
INTO THE WEEKEND...DUE TO THE UNSEASONABLY WARM AND VERY HUMID AIR
OVER-RIDING THE COOLER SHELF WATERS. WINDS MIGHT BE A LITTLE TOO
STRONG WEDNESDAY INTO WEDNESDAY NIGHT TO KEEP THE DENSE FOG TO A
MINIMUM. BUT LIGHTER WIND FIELDS THURSDAY INTO THE WEEKEND COULD
RESULT IN A GREATER COVERAGE OF DENSE FOG. EITHER WAY...MARINE
DENSE FOG ADVISORIES APPEAR HIGHLY LIKELY...WITH THE POSSIBILITY
THAT THE FOG WILL IMPACT CHARLESTON HARBOR AT TIMES EACH MORNING
AND AGAIN DURING MUCH OF THE NIGHT TIME HOURS THROUGH THE PERIOD.
THUNDERSTORMS...MARINERS ARE ADVISED THAT ISOLATED TO SCATTERED
THUNDERSTORMS WILL OCCASIONALLY IMPACT THE COASTAL WATERS...AND
SIMILAR TO TUESDAY THERE WILL BE THE RISK FOR WIND GUSTS
APPROACHING 34 KT AT TIMES.
&&
.CLIMATE...
RECORD HIGHS FOR DECEMBER 23RD...
KCHS...82/2013.
KCXM...76/1990.
KSAV...81/1956.
RECORD HIGHS FOR DECEMBER 24TH...
KCHS...76/1988.
KCXM...76/1921.
KSAV...80/1931.
RECORD HIGHS FOR DECEMBER 25TH...
KCHS...80/2008.
KCXM...76/2008 (MULTIPLE YEARS).
KSAV...80/2008 (MULTIPLE YEARS).
RECORD HIGHS FOR DECEMBER 26TH...
KCHS...78/1942.
KCXM...74/1982 (MULTIPLE YEARS).
KSAV...79/1987.
RECORD HIGH MINIMUMS FOR DECEMBER 23RD...
KCHS...66/1990.
KCXM...68/1990.
KSAV...65/1990.
RECORD HIGH MINIMUMS FOR DECEMBER 24TH...
KCHS...60/1964.
KCXM...60/1964.
KSAV...62/1879.
RECORD HIGH MINIMUMS FOR DECEMBER 25TH...
KCHS...62/2008 (MULTIPLE YEARS).
KCXM...63/1964 (MULTIPLE YEARS).
KSAV...65/1932.
RECORD HIGH MINIMUMS FOR DECEMBER 26TH...
KCHS...67/1964.
KCXM...66/1964.
KSAV...63/1987 (MULTIPLE YEARS).
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...DENSE FOG ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR AMZ350-352-
354.
SMALL CRAFT ADVISORY UNTIL 5 PM EST THURSDAY FOR AMZ374.
SMALL CRAFT ADVISORY FROM 7 AM WEDNESDAY TO 11 AM EST THURSDAY
FOR AMZ350.
&&
$$
ST
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1002 PM EST TUE DEC 22 2015
.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
ISSUED AT 256 PM EST TUE DEC 22 2015
PATTERN TO REMAIN MILD THROUGH AND BEYOND THE SEVEN DAY FORECAST.
A COUPLE OF SIGNIFICANT STORMS SYSTEMS...WEDNESDAY WITH POTENTIAL
DAMAGING WIND...AND THIS WEEKEND...WITH HEAVY RAIN THAT MAY LEAD
TO FLOODING...WILL FINISH OUT THE ACTIVE WEATHER PATTERN LATE THIS
YEAR.
&&
.NEAR TERM /REST OF TONIGHT/...
ISSUED AT 1002 PM EST TUE DEC 22 2015
AFTER SOME SUNSHINE FOR MOST LATE THIS AFTERNOON...LOWER STRATUS
HAS ADVECTED BACK ACROSS MOST OF THE FORECAST AREA AS OF 03Z WITH
MOISTURE STREAMING NORTH AND INTERACTING WITH THE SHALLOW
INVERSION STILL PRESENT. FAR NORTHERN COUNTIES HAVE MANAGED TO
DROP QUICKLY INTO THE MID AND UPPER 30S THIS EVENING WHERE SKIES
HAVE REMAINED CLEAR THE LONGEST...WITH TEMPS RANGING FROM THE MID
40S TO LOWER 50S OVER MOST OF THE REST OF THE FORECAST AREA.
PIECES ALREADY STARTING TO ALIGN THAT WILL BRING THE WARM
TEMPERATURES WEDNESDAY ALONG WITH THE UNUSUAL SEVERE WEATHER RISK
FOR THE AFTERNOON AND EVENING WEDNESDAY. POLEWARD MOISTURE RETURN
OVER THE LAST 6 HOURS FROM THE GULF COAST HAS BEEN IMPRESSIVE TO
OUR SOUTH TO PUT IT MILDLY. 60+ DEGREE DEWPOINTS NOW WELL INTO THE
TENNESSEE VALLEY AND WILL LIKELY ADVANCE INTO KENTUCKY AFTER
MIDNIGHT. ALREADY SEEING PATCHY FOG IN THE LOWER WABASH VALLEY AS
THE DEEPER MOISTURE ARRIVES AND EXPECT THAT TO CONTINUE OVERNIGHT
IN SOME AREAS.
LOWS HAVE ALREADY BEEN MET...WITH TEMPERATURES STEADILY
CLIMBING FOR THE REST OF THE NIGHT AS WARM MOIST AIR SPREADS
NORTH. RAP AND NAM BOTH HINTING AT SURFACE TEMPS NEAR 60 OVER
SOUTHERN FORECAST AREA BY DAYBREAK AND CONSIDERING CURRENT TEMPS
OVER THE TENNESSEE AND LOWER MISSISSIPPI VALLEYS...THAT DOES NOT
SEEM FAR OFF.
CONVECTION ACROSS THE LOWER MISSISSIPPI VALLEY WILL RACE NORTHEAST
OVERNIGHT AND WHILE BULK OF THE ACTIVITY SHOULD REMAIN TO THE
SOUTHEAST OF THE FORECAST AREA...HI-RES GUIDANCE CONTINUING TO
CAPTURE SCATTERED SHOWERS INCREASING IN COVERAGE AFTER 06Z FROM
THE SOUTH AS WARM ADVECTION INTENSIFIES OVER THE OHIO VALLEY.
HAVE ADJUSTED POPS SLIGHTLY...BUT INTRODUCING LOW CHANCES FOR
ENTIRE FORECAST AREA FOR THE PREDAWN HOURS. MEANWHILE BACK TO THE
SOUTHWEST...EXPECT RAPID CONVECTIVE DEVELOPMENT OVER THE OZARKS AS
THE INTENSE LOW PRESSURE SWINGS OUT THROUGH THE CENTRAL PLAINS AND
BEGINS TO INTERACT WITH THE GULF MOISTURE FETCH. THIS WILL
CONTINUE TO INCREASE IN COVERAGE AND EXPAND INTO THE REGION BY MID
TO LATE MORNING WEDNESDAY.
ZONE AND GRID UPDATES OUT.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY/...
ISSUED AT 256 PM EST TUE DEC 22 2015
FORECAST ISSUE IS SEVERE WEATHER THREAT WEDNESDAY. THOUGH MODEL
DYNAMICS IN FAIRLY GOOD AGREEMENT...AMOUNT OF DESTABILIZATION
PRIOR TO MAIN SHOWER/SQUALL BAND ARRIVAL IN THE AFTERNOON MAY
DETERMINE HOW GUSTY CONVECTION MAY GET. MODEL SOUNDINGS SUGGEST
MIXING OF 40MPH GUSTS TO THE GROUND PRIOR TO ANY STORM LINE MAY
OCCUR AS WELL SO HAVE INCLUDED GUSTY WORDING IN THE FORECAST.
NAM SOMEWHAT DIFFERENT THAN OTHER MODELS IN HAVING QUITE DISTINCT
AND SIMILARLY POTENT ROUNDS OF STORMS...AFTERNOON AND THEN EVENING
WITH COLD FRONT TIED WITH TWO INSTABILITY AXES. WILL LEAN TOWARD
A BLEND OF MODELS AND FORECAST WORDING MAY NOT REFLECT THE
SEPARATION BUT TWO HEAVIER ROUNDS OF RAIN APPEAR POSSIBLE.
STRENGTH OF WARM ADVECTION SHOULD LEAD TO ADVERTISED RECORD OR
NEAR RECORD HIGHS IN THE UPPER 60S WEDNESDAY.
WEDNESDAY NIGHT...NAM IS SLOWEST WITH COLD FRONT WHILE GFS IS
QUITE FAST SO WILL AVERAGE BETWEEN THESE. END RESULT IS AT LEAST
ONE MORE DECENT SHOT OF RAIN WITH COLD FRONT PASSAGE DURING THE
EVENING WITH LINGERING SHOWERS ENDING BEFORE DAYBREAK.
THURSDAY AND PART OF FRIDAY...A DRY TRANQUIL PERIOD IS IN STORE
AS HIGH PRESSURE BUILDS IN BEHIND THE INTENSIFYING LOW THAT LIFTS
NE INTO THE HUDSON BAY AREA. HAVE KEPT TEMPERATURES NEAR GUIDANCE
AND STILL WELL ABOVE NORMAL WITH HIGHS MAINLY IN THE 50S AND LOWS
ABOVE FREEZING.
AS THE NEXT STRONG SHORTWAVE DUMPS INTO THE WESTERN TROUGH...THE
SURFACE BOUNDARY THAT SLIPPED INTO KENTUCKY THURSDAY WILL LIFT
BACK NORTH TO BEGIN THE NEXT RAINY PERIOD.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
ISSUED AT 232 PM EST TUE DEC 22 2015
ECMWF CONTINUES TO SUGGEST STRONG SOUTHWEST FLOW ALOFT OVER THE
EASTERN HALF OF THE UNITED STATES DURING THIS PERIOD...WITH MILD AND
MOIST GULF AIR FLOWING NORTH INTO THE OHIO VALLEY. A DEEP LOW
DEVELOPING OVER THE AMERICAN SOUTHWEST WILL GRADUALLY PUSH EAST
INTO TEXAS DURING THIS PERIOD...OCCASIONAL EJECTING WEAK SHORT
WAVES INTO THE SW FLOW ALOFT TOWARD THE OHIO VALLEY THROUGH
TUESDAY. MEANWHILE IN THE LOWER LEVELS A FRONTAL BOUNDARY IS
EXPECTED TO LINGER ACROSS CENTRAL INDIANA AND THE OHIO VALLEY
THROUGH MUCH OF THE PERIOD...PROVIDING A FOCUS FOR LOWER LEVEL
CONVERGENCE AND PRECIPITATION. THUS WILL AGAIN CONTINUE THE
ONGOING FORECAST THROUGH THE PERIOD WITH PLENTY OF POPS AND ABOVE
NORMAL TEMPERATURES.
&&
.AVIATION /DISCUSSION FOR THE 230300Z KIND TAF UPDATE/...
ISSUED AT 930 PM EST TUE DEC 22 2015
IFR CEILINGS AROUND 008 AGL HAVE ALREADY MOVED INTO THE KIND TERMINAL.
THIS HAS BEEN ADDRESSED WITH AN EARLIER UPDATE.
SHORT TERM MODEL GUIDANCE SUGGESTS THERE MAY A WINDOW BETWEEN
230400Z-230800Z WHERE THE LOW CEILINGS MAY TEMPORARILY SCATTER OUT AT
THE KIND TERMINAL AS SOME DRIER AIR WORKS IN FROM THE SOUTHEAST.
CEILINGS HAVE IMPROVED OVER SOUTHEAST INDIANA RECENTLY...SO THIS
SCENARIO IS POSSIBLE. WILL CONTINUE TO MONITOR TRENDS.
PREVIOUS DISCUSSION FOLLOWS.
AREAS OF CEILINGS 010-015 CONTINUE ACROSS CENTRAL INDIANA...WITH
SOME BREAKS IN THE CLOUD COVER OVER THE KIND/KBMG TERMINALS. SUSPECT
THIS WILL BE SHORT LIVED AS SATELLITE INDICATES CEILINGS EXPANDING
RATHER RAPIDLY NORTHWARD OVER SOUTHERN INDIANA. NOCTURNAL COOLING OF
THE BOUNDARY LAYER AND MOIST ADVECTION SHOULD ALLOW FOR CEILINGS TO
FALL INTO THE IFR CATEGORY AFTER ABOUT 230500Z. SOME VISIBILITY
RESTRICTIONS IN FOG ALSO PROBABLE IN THE HOURS PRIOR TO DAYBREAK
WEDNESDAY...BUT THE CEILINGS SHOULD BE THE BIGGER ISSUE.
SURFACE WINDS 130-160 DEGREES AT 6-9 KTS TONIGHT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...TUCEK
NEAR TERM...RYAN
SHORT TERM...TUCEK
LONG TERM....PUMA
AVIATION...JAS
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
337 PM EST MON DEC 21 2015
.SYNOPSIS...
ISSUED AT 331 PM EST MON DEC 21 2015
A CHANCE OF SHOWERS ALONG WITH AREAS OF DRIZZLE WILL PERSIST INTO
TONIGHT WITH OVERNIGHT LOWS FALLING INTO THE LOWER 40S.
TEMPERATURES WILL NOT WARM MUCH ON TUESDAY AS CLOUD COVER HOLDS
STRONG WITH HIGHS REACHING THE MIDDLE 40S TO AROUND 50. CHANCES
FOR SHOWERS AND POSSIBLY A FEW THUNDERSTORMS WILL ARRIVE WEDNESDAY
INTO WEDNESDAY EVENING ALONG WITH RECORD BREAKING HIGHS FROM THE
UPPER 50S TO MIDDLE 60S.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 331 PM EST MON DEC 21 2015
KIWX RADAR SHOWING DIMINISHING TRENDS IN BOTH INTENSITY AND COVERAGE
OF SHRA THIS AFTERNOON. WATER VAPOR IMAGERY AND RUC ANALYSIS
DEPICTING LEAD SHORT WAVE MOVING NE ACROSS SOUTHERN GREAT LAKES
REGION WITH TRAILING UPPER TROF MOVING INTO THE PLAINS STATES.
CONTINUED SW FLOW ALOFT WILL BRING SECOND DISTURBANCE NE INTO
SOUTHERN GREAT LAKES BY TUESDAY MORNING WHICH WILL KEEP SMALL
CHANCES FOR LIGHT PRECIP OVERNIGHT. FORECAST SOUNDINGS INDICATING
2KFT SATURATED LAYER BELOW LOW LEVEL INVERSION WHICH WILL BRING
POTENTIAL FOR PATCHY FOG/DRIZZLE OVERNIGHT AS WELL. STRONG UPPER JET
DYNAMICS COMING ONSHORE INTO THE PACIFIC NW WILL AMPLIFY THE PATTERN
AND INDUCE 80-100M HEIGHT RISES OVER OUR AREA TUESDAY WHICH WILL
PROVIDE A BRIEF BREAK IN PRECIP. PATTERN REMAINS UNSEASONABLY MILD
THIS PERIOD WITH LOWS IN THE L40S AND HIGHS 45-50.
&&
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 331 PM EST MON DEC 21 2015
INCREASINGLY DYNAMIC PATTERN WILL BE SETTING UP FOR THE REGION
THROUGH THE REMAINDER OF THE LONG TERM AND BEYOND WITH INITIAL
FOCUS ON STRONG MID WEEK SYSTEM.
FIRST UPPER LEVEL WAVE OF INTEREST HAS NOW MADE IT ONSHORE IN THE NW
STATES WITH A PIECE OF THIS STARTING TO DROP SOUTH INTO THE PLAINS
BY TUESDAY. AS IT DOES...THE UPPER FLOW WILL BUCKLE SENDING YET
ANOTHER SURGE OF WARM AND INCREASINGLY HUMID (UNSTABLE?) AIR INTO
THE REGION FOR WEDNESDAY AND WEDNESDAY NIGHT. AS MENTIONED IN
OVERNIGHT DISCUSSION...FOCUS ON NOT ONLY HEAVY RAIN BUT ALSO SEVERE
POTENTIAL LOOMS ESPECIALLY WEDS AFTERNOON AND EVENING. FIRST FOR
RAINFALL...PWATS OF AROUND 1.25" OR GREATER WILL FUNNEL IN AHEAD OF
THE FRONT ON 50+ KT LOW LEVEL JET BY WEDNESDAY AFTERNOON. JUST
ENOUGH INSTABILITY GETS INTO THE AREA LATE AFTERNOON/EARLY EVENING
WITH SFC BASED CAPES BETWEEN 250 AND 500 J/KG WITH 0-6 KM BULK SHEAR
IN EXCESS OF 70 KNOTS WEDNESDAY NIGHT. THIS WOULD SET THE STAGE FOR
A POTENTIAL OF LOW TOPPED SUPERCELLS IN A LOW CAPE/HIGH SHEAR
ENVIRONMENT. NOW...THE DRAWBACKS...PREFRONTAL TROUGH MAY HAVE
ALREADY SHIFTED ACROSS THE AREA PRIOR TO THE ARRIVAL OF THE PHASING
OF THESE FEATURES WITH NAM SHOWING STG-SVR STORMS CLOSER TO THE OHIO
RIVER AND POINTS SOUTH. FOR NOW HAVE EXPANDED THUNDER MENTION INTO
WEDS EVENING AND WENT CHC VS SLGT CHC. WILL TOUCH UP HWO TO EXTEND
WIND THREAT INTO WEDS EVE BUT HOLD OFF ON ANY MENTION OF SEVERE FOR
THE MOMENT. SPC DAY3 OUTLOOK DOES HAVE MUCH OF OUR AREA IN MARGINAL
RISK WITH GREATER RISK BY FAR FURTHER SOUTH. WITH REGARDS TO
TEMPERATURES UNTIL THE DEEP LOW PASSES...OVERNIGHT LOWS WILL OCCUR
TUESDAY EVENING WITH CLIMBING TEMPS THROUGH THE NIGHT INTO WEDNESDAY
AS HIGHS TOP OUT AT WHAT SHOULD BE RECORD VALUES.
A BRIEF DRY PERIOD WILL BE IN STORE FOR THURS AND THURS NIGHT BEFORE
2 WAVES MOVE TOWARDS THE AREA. THE FIRST WILL BE ON THE WEAKER SIDE
(AT LEAST IN COMPARISON TO NEXT WEEKS SYSTEM) BUT WILL HELP
REINFORCE THE BOUNDARY TO OUR SOUTH AND BEGIN TO PUSH IT BACK NORTH
WITH RAIN CHANCES INCREASE ESPECIALLY SAT AND SAT NGT WHERE HIGH CHC
TO LIKELY POPS ARE WARRANTED GIVEN THE ACTIVE PATTERN. TOWARDS THE
END AND ESPECIALLY OUTSIDE THE FORECAST PERIOD A POWERFUL STORM
LOOKS TO TAKE SHAPE ACROSS THE SW STATES AND EJECT INTO THE EASTERN
PLAINS/WESTERN GREAT LAKES. THIS WILL LIKELY BRING MORE RAIN TO THE
AREA ALONG WITH A THREAT OF STORMS. ALSO GIVEN THE SERIES OF
SYSTEMS...HYDRO CONCERNS COULD INCREASE BETWEEN CHRISTMAS AND NEW
YEARS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED
AT 1230 PM EST MON DEC 21 2015
RADAR TRENDS SHOWING PRECIP MOVING OUT OF THE AREA GOING INTO THE
AFTERNOON HOURS AS LEAD SHORT WAVE MOVES NE THROUGH THE GREAT LAKES
REGION. BREEZY S/SW WINDS WILL CONTINUE TO BEGIN THE TAF PERIOD
ALTHOUGH PROXIMITY OF SURFACE LOW MAY LIMIT GUSTS AT KSBN. UPSTREAM
OBS INDICATING IFR CIGS WILL CONTINUE THIS AFTERNOON WITH POTENTIAL
FOR SOME IMPROVEMENT BY EARLY EVENING BEFORE APPROACH OF SECOND
UPPER LEVEL DISTURBANCE TONIGHT BRINGS A CHANCE FOR A FEW SHOWERS
ALONG WITH IFR CIGS. HIRES MODELS AND FORECAST SOUNDINGS INDICATING
LOW LEVEL INVERSION OVERNIGHT AND PERSISTING INTO TUESDAY MORNING
WILL KEEP LOWEST 2KFT SATURATED AND POTENTIAL FOR CIGS TO DROP DOWN
TO LIFR. SURFACE LOW EXPECTED TO LIFT NE TUESDAY AND ALLOW WEAK HIGH
PRESSURE TO BUILD INTO THE AREA WHICH WILL BRING GRADUALLY IMPROVING
CONDITIONS TOWARD THE END OF THE TAF PERIOD.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SYNOPSIS...FISHER
SHORT TERM...JAL
LONG TERM...FISHER
AVIATION...LOGSDON
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AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
1259 AM EST MON DEC 21 2015
.SYNOPSIS...
ISSUED AT 1258 AM EST MON DEC 21 2015
THIS WEEK WILL FEATURE WELL ABOVE NORMAL TEMPERATURES AND SEVERAL
OPPORTUNITIES FOR RAIN AS UPPER LEVEL SYSTEMS LIFT NORTHEAST
THROUGH THE REGION. THE FIRST SYSTEM MOVES THROUGH TODAY WITH
WIDESPREAD RAIN...ESPECIALLY DURING THE MORNING AND EARLY
AFTERNOON HOURS. AFTER A BRIEF DRY PERIOD ON TUESDAY...RAIN
SHOWERS LIKELY RETURN WEDNESDAY INTO WEDNESDAY NIGHT. HIGHS TODAY
AND TUESDAY WILL GENERALLY RANGE BETWEEN THE UPPER 40S AND LOW
50S...WITH RECORD WARMTH INTO THE LOW TO MID 60S POSSIBLE
WEDNESDAY. COOLER AND DRIER WEATHER IS THEN EXPECTED TO RETURN
THURSDAY INTO FRIDAY...WITH RENEWED RAIN CHANCES BY NEXT WEEKEND.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 336 PM EST SUN DEC 20 2015
WATER VAPOR IMAGERY AND LATEST RUC ANALYSIS DEPICTING UPPER TROF
OVER THE FOUR CORNERS WITH POTENT 120KT UPPER JET MOVING UP THE
EAST SIDE OF THE TROF AXIS. THIS ENERGY WILL EJECT EASTWARD AND
HELP ORGANIZE DEVELOPING SURFACE LOW IN THE PLAINS. DESPITE
PROGRESSIVE NATURE OF THIS SYSTEM...IMPRESSIVE DYNAMICS WILL AID
IN DECENT MOISTURE TRANSPORT INTO THE REGION OVERNIGHT AND SUPPORT
WIDESPREAD LIGHT TO MODERATE RAIN. GOOD ISENTROPIC ASCENT AHEAD OF
THIS SYSTEM WILL RAPIDLY SATURATE THE LOW LEVELS AFTER 06Z IN OUR
WESTERN CWA WITH ARRIVAL OF 60KT LLJ EARLY MONDAY MORNING. WILL
TREND ARRIVAL OF PRECIP IN A NW/SE ORIENTATION WITH NW CWA
BECOMING LIKELY SHORTLY AROUND 06Z AND SE BY 09Z MONDAY. MODELS IN
DECENT AGREEMENT WITH BRINGING WEAK DRY SLOT INTO THE AREA MONDAY
AFTERNOON WHICH WILL DIMINISH...BUT NOT ELIMINATE...POPS DOWN TO
CHANCE/SLIGHT CHANCE. WARM AIR ADVECTION PATTERN ON STRONG
SOUTHERLY FLOW WILL LIMIT DIURNAL TEMP CHANGES DURING THE PERIOD
WITH LOWS TONIGHT NEAR 40F AND HIGHS NEAR 50F OVER MOST OF THE CWA
MONDAY.
&&
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 336 PM EST SUN DEC 20 2015
RETURN TO ABOVE TO WELL ABOVE NORMAL TEMPERATURES FOR MOST IF NOT
ALL THE FORECAST PERIOD...WITH A FEW CHANCES FOR
RAINFALL...ESPECIALLY MIDWEEK.
LOW PRESSURE WILL BE QUICKLY EXITING TO THE NORTHEAST OF THE AREA
WITH A TRAILING DISTURBANCE MOVING THROUGH THE AREA MONDAY NIGHT.
SOME WEAK LIFT IS DEPICTED IN ALL MODELS IN THE LOWEST LEVELS WITH
NAM THE MOST PRONOUNCED. NOT SURE ABOUT HOW MUCH OF THE PRECIP
WILL BE MEASURABLE RAIN VS DRIZZLE GIVEN SHALLOW NATURE OF LIFT.
WILL KEEP WITH SLGT CHC TO CHC POPS AND ADD MENTION OF PATCHY
DRIZZLE THROUGH THE NIGHT. LITTLE SIGNIFICANT CHANGE IN SURFACE
TEMPERATURES MON NGT INTO TUESDAY WITH ONLY A GLANCING BLOW OF
SLIGHTLY COLDER BUT STILL ABOVE NORMAL) AIR.
FOCUS THEN SHIFTS TO DEEP TROUGH DIGGING INTO THE CENTRAL PLAINS
WHICH WILL EJECT TOWARDS THE REGION WEDNESDAY INTO WEDNESDAY NIGHT
ADVECTING WARMER AND MORE HUMID AIR (PWATS 0.75 TO 1 INCH) INTO
THE REGION. WITH CURRENTLY FORECASTED HIGHS OF 60 OR
HIGHER...RECORD HIGH TEMPERATURES WILL BE BROKEN FOR BOTH SOUTH
BEND AND FT WAYNE (59 IN 1933 AND 59 IN 1941 RESPECTIVELY).
SHOWERS CHANCES WILL INCREASE FROM WEST TO EAST WEDNESDAY
AFTERNOON INTO WEDNESDAY NIGHT WITH ALL LOCATIONS TO SEE AT LEAST
SOME MEASURABLE RAINFALL. HEAVIEST AXIS OF RAINFALL LOOKS TO
REMAIN INTO ILLINOIS. NEIGHBORS TO THE WEST AND SOUTH HAVE ADDED
MENTION OF THUNDER AND WHILE NAM/GFS DO ATTEMPT BRING A NARROW
RIBBON OF NEAR ZERO SHOWALTERS IN BETWEEN 00Z AND 6Z NOT CONVINCED
COVERAGE (IF ANY) WILL BE ENOUGH TO WARRANT A MENTION.
GIVEN THE WESTERLY TRACK OF THE LOW AND RELOADING OF AN EVEN
STRONGER TROUGH IN THE WEST...NO MAJOR COLD AIR ARRIVES WITH
READINGS DROPPING BACK TO THE 40S AND 50S...STILL WELL ABOVE THE
NORMALS IN THE UPPER 30S AND NOT BODING WELL FOR ANY CHANCES OF A
WHITE CHRISTMAS FOR THE AREA. LARGE MODEL DIFFERENCES EXIST WITH
HANDLING OF CLOSED UPPER LOW AND ITS IMPACTS THIS WEEKEND. HAVE
CONTINUED WITH SLGT CHC TO CHC POPS STARTING FRIDAY NIGHT AND
PERSISTING THROUGH THE WEEKEND. TEMPERATURES MAY RETURN TO NEAR
NORMAL LEVELS AT THE END OF THE PERIOD BUT GIVEN LARGE MODEL
DIFFERENCES NOT SURE IF THIS WILL HOLD TRUE OR NOT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1258 AM EST MON DEC 21 2015
FLIGHT CONDITIONS WILL STEADILY WORSEN THIS MORNING AS RAIN AND
ASSOCIATED TOP DOWN SATURATION OVERSPREADS IN ADVANCE OF A
MID LEVEL WAVE APPROACHING FROM KANSAS. BULK OF RAIN WILL LIFT
OUT OF THE AREA THIS AFTN AS FOCUSED DEEP LAYER ASCENT/MOISTURE
CONVERGENCE EXITS. HOWEVER...STILL EXPECT IFR TO LOW MVFR
CONDITIONS AND AREAS OF DRIZZLE/LIGHT RAIN INTO THE LATE AFTN/EVE
GIVEN SATURATED LOW LEVELS ALONG A TRAILING SFC TROUGH.
OTHERWISE...GUSTY SSW WINDS/WIND SHEAR CONCERNS EXPECTED THIS
MORNING/EARLY AFTN WITHIN STRONG LOW LEVEL JET CORE.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR LMZ043-
046.
&&
$$
SYNOPSIS...STEINWEDEL
SHORT TERM...JAL
LONG TERM...FISHER
AVIATION...STEINWEDEL
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AREA FORECAST DISCUSSION
NWS DES MOINES IA
544 PM CST TUE DEC 22 2015
.SHORT TERM /TONIGHT/...
ISSUED AT 345 PM CST TUE DEC 22 2015
REMNANTS OF THE MORNING STRATUS SHIELD REMAIN OVER THE NORTHEASTERN
THIRD TO HALF OF THE STATE AND WILL GENERALLY REMAIN SO THIS EVENING
AS THE STRONG INVERSION REMAINS IN PLACE AND WE LOSE WHATS LEFT OF
ANY DAYTIME HEATING AND MIXING. AS A RESULT...CEILINGS AND
VISIBILITIES WILL CONTINUE TO BE LOW IN THOSE AREAS...AROUND 500
FEET AND A COUPLE MILES OR LESS RESPECTIVELY THROUGH THE SHORT TERM.
HAVE NOT CURRENTLY INTRODUCED FOG INTO THE GRIDS...BUT MAY WARRANT
SO DURING THE EVENING...ESPECIALLY FOR AREAS THAT HOLD OFF ON SEEING
PRECIP LONGER AND MOISTURE ADVECTION CONTINUES. AREAS THAT SAW
CLEARING WILL PROGRESSIVELY SEE HIGH BASED CLOUDS MOVE IN BEFORE
CEILINGS FALL AGAIN AS SURFACE LOW AND FORCING PROGRESSES TOWARDS
THE REGION FROM CENTRAL/EASTERN KANSAS.
THE AFOREMENTIONED SURFACE LOW WILL BE THE MAIN CONCERN IN THE SHORT
TERM...BEGINNING TO REALLY INFLUENCE THE AREA AFTER 03Z. THROUGH THE
DAY...NAM AND HRRR HAVE TENDED TO HANDLE THE CLEARING BEST...SO HAVE
TRENDED THAT WAY IN THE GRIDS FOR THIS EVENING. WITHIN THE SHORT
TERM WINDOW...BEST INITIAL FORCING IS THERMODYNAMIC WITH A GOOD PUSH
OF THETA-E ADVECTION ALONG WITH ISENTROPIC LIFT IN THE 290K REGION.
THE DEFORMATION ZONE WILL ALSO BEGIN TO SET UP IN NORTHWEST IOWA
AFTER 06Z...FURTHER BOOSTING LIFT. CURRENTLY...THE COLUMN IS QUITE
DRY FROM ABOUT 850MB TO 500MB...WHICH CALLS INTO SOME QUESTION WHEN
THE COLUMN WILL SATURATE AND PRECIP WILL BEGIN...BUT BEGAN TO UP
POPS IN NORTHWEST IOWA AROUND 5Z AND THROUGH THE SHORT TERM WINDOW
IN CONJUNCTION WITH HRRR/NAM SOLUTIONS.
.LONG TERM /WEDNESDAY THROUGH TUESDAY/...
ISSUED AT 345 PM CST TUE DEC 22 2015
THE LONG TERM REMAINS ACTIVE WITH SEVERAL SHORTWAVES EJECTING OUT
OF THE BAST OF A LONG WAVE TROUGH OUT WEST. WE BEGIN THE PERIOD
WITH THE SYSTEM AFFECTING THE SHORT TERM LIFTING NORTHEAST. THERE
WILL BE A BRIEF PERIOD OF OF SNOW ON THE BACKSIDE OF THIS SYSTEM
AS IT LIFTS OFF TO THE NORTHEAST. MOST OF THE FORCING EXITS BEFORE
THE CHANGEOVER SO I AM NOT LOOKING AT MUCH ACCUMULATION PLUS WE
WILL BE TOO WARM ALOFT...MAY EVEN SEE A BIT OF FREEZING RAIN WITH
THIS. ALSO...SOME INSTABILITY WORKS INTO EASTERN IOWA AS THIS
SYSTEM LIFTS OUT WHICH MEANS WE COULD SEE SOME ISOLATED THUNDER
WEDNESDAY AFTERNOON. AFTER THIS SYSTEM DEPARTS THERE WILL BE A
BRIEF RESPITE WEDNESDAY NIGHT BEFORE ANOTHER WEAK SHORTWAVE
TRANSLATES ACROSS THE SOUTH AND EAST. TEMPS WILL BE WARM ENOUGH
FOR RAIN WITH THIS SO NOT FORESEEING MUCH IN THE WAY OF TRAVEL
PROBLEMS BUT WITH RIVERS STILL VERY HIGH...ANY HEAVIER RAINFALL
WILL LIKELY RESULT IN FLOODING AGAIN.
THE NEXT MAIN SYSTEM WILL BE A DEEPENING LOW ACROSS THE SOUTHERN
PLAINS LIFTING NORTHEAST. I THINK THE MODELS ARE LIKELY TOO FAST
WITH THIS SYSTEM GIVEN HOW THE LOW IS DEEPENING BUT INITIALLY THIS
WILL BE A RAIN PRODUCER WITH COLD AIR WRAPPING INTO THE LOW
CHANGING PRECIP OVER TO SNOW. THIS ONE MAY BE A POTENTIAL SNOW
PRODUCER FOR US AND NEEDS TO BE WATCHED BUT WILL ALSO BRING
ADDITIONAL FLOODING THREATS.
&&
.AVIATION...23/00Z
ISSUED AT 540 PM CST TUE DEC 22 2015
SOUTHERN SITES...KDSM AND KOTM...WILL SEE VFR CONDITIONS EARLY
BEFORE LOWER CEILINGS AND VISIBILITIES MOVE IN WITH APPROACHING LOW
PRESSURE SYSTEM.CEILINGS AND VISIBILITIES WILL REMAIN PRIMARILY
MVFR ACROSS SITES THROUGH PERIOD WITH CONDITIONS DROPPING TO IFR
OR LIFR AT TIMES WITH RA AT SITES....GENERALLY AFTER 12Z THROUGH
00Z. WINDS WILL BE STRONG AND GUSTY BEYOND 12Z...INCREASING AND
BECOMING NORTHWESTERLY LATE IN THE PERIOD.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CURTIS
LONG TERM...FAB
AVIATION...AWB
AREA FORECAST DISCUSSION
National Weather Service Topeka KS
1136 PM CST SUN DEC 20 2015
...Update to aviation forecast discussion...
.UPDATE...
Issued at 526 PM CST SUN DEC 20 2015
Have increasing confidence in an area of showers and a few
embedded thunderstorms developing and tracking from central KS
into northeast and east central KS from mid-evening through the
early morning hours. Have increased precip chances in these areas
with confidence very high in the development of this area of
precip, but PoPs muted because of the expected scattered nature
and relatively small area of focused ascent. The driving force for
the majority of this precipitation will be the strong forcing
immediately ahead of the compact upper level short wave forecast
to track from southwest through northeast Kansas in the next 12
hours. Still see signs of elevated instability developing in
advance of this forcing so embedded thunderstorms remain possible
as well.
&&
.SHORT TERM...(Today and Tonight)
Issued at 257 AM CST SUN DEC 20 2015
Winds already picking up in the early morning hours, with winds
aloft forecast to increase and stay up through the day today. This
has kept overnight lows up in the 40s most areas. As the boundary
layer mixes out this morning, RAP and GFS suggest winds at the top
of the mixed layer are close to 50 kts. As a result, expect high
temperatures to make it into the middle/upper50s, and wind speeds to
gust near wind advisory criteria of 40 kts. Will hoist a wind
advisory for those counties along and south of I-70. Still a chance
for some light drizzle and light rain to develop late this morning
in the WAA regime, followed by precip chances continuing due to the
shortwave trof moving eastward out of the high plains later this
evening. These showers could also aid in mixing down some of the
stronger wind speeds through the day today.
Both GFS and NAM indicating just a few hours with some weak
instability in the column in the midnight to 3am timeframe as the
stronger lift and cold pool aloft move over the eastern part of the
state. Have left thunder out at this time given small window, but
is worth mentioning here. As trof moves eastward, cooler air moves
in behind and lows fall into he 20s to middle 30s.
.LONG TERM...(Monday through Saturday)
Issued at 257 AM CST SUN DEC 20 2015
On Monday another mid level trough tracks over the central US, which
should not have much effect on the overall weather. Highs will be
cooler in the mid to upper 40s. On Tuesday return flow quickly
develops as yet another shortwave approaches from the west, which
will allow temperatures to warm back into the 50s. This shortwave
trough appears to deepen Tuesday night as it passes over the
forecast area. Increased moisture and lift as well as an advancing
cold front could support rain Wednesday morning and into the
afternoon. This precip appears to stay confined to portions of
eastern KS. Towards the end of the week a few of the models continue
to bring out weak shortwaves that could cause light precip, but
confidence in timing and location is low at this point. Models
continue to show a strong system over the southern Rockies over the
weekend, but also continue to struggle on how to evolve that
system.
&&
.AVIATION...(For the 06Z TAFS through 06Z Monday Night)
Issued at 1133 PM CST SUN DEC 20 2015
Showers and embedded TS will impact TAF sites between now and
around 09Z, ending at MHK slightly before that time. A cold front
with winds shifting out of the northwest will impact MHK near
0730Z and TOP/FOE between 09Z and 10Z. MVFR cigs are likely to
persist through this period and into the morning hours with an
expectation to scatter in the late morning to early afternoon time
frame.
&&
.TOP Watches/Warnings/Advisories...
NONE.
&&
$$
UPDATE...Barjenbruch
SHORT TERM...67
LONG TERM...Sanders
AVIATION...Barjenbruch
AREA FORECAST DISCUSSION
NWS JACKSON KY
101 PM EST MON DEC 21 2015
.UPDATE...
ISSUED AT 101 PM EST MON DEC 21 2015
MADE MINOR ADJUSTMENTS TO THE FORECAST BASED ON MID DAY OBS...BUT
WITH NO SUBSTANTIVE CHANGE TO THE OVERALL FORECAST.
UPDATE ISSUED AT 1125 AM EST MON DEC 21 2015
FIRST ROUND OF PRECIP HAS EXITED TO THE EAST...AND ANOTHER ROUND
IS HEADING IN FROM THE WEST. HAVE MADE MINOR UPDATES TO GRIDS FOR
THE TIMING. WITH CLOUDS AND PRECIP...TEMPS ARE RISING A BIT SLOWER
THAN WAS FORECAST. HAVE KNOCKED DOWN AFTERNOON HIGHS SLIGHTLY.
UPDATE ISSUED AT 846 AM EST MON DEC 21 2015
AN AREA OF LIGHT RAIN IS MOVING EAST ACROSS THE REGION...BUT IS
GRADUALLY DIMINISHING AS IT MOVES INTO DRIER AIR. HAVE UPDATED THE
GRIDS FOR TIMING OF THIS PRECIP. HAVE ALSO BLENDED EARLY MORNING
OBSERVED TEMPS/DEW POINTS INTO THE DAYTIME FORECAST.
UPDATE ISSUED AT 620 AM EST MON DEC 21 2015
A LINE OF MEASURABLE RAIN SHOWERS IS MAKING STEADY PROGRESS
THROUGH CENTRAL KENTUCKY AND WILL BE IN HERE SHORTLY AFTER 12Z.
WILL UPDATED THE POPS TO BETTER TIME THIS FEATURE. ALSO...SOME OF
THE EASTERN VALLEYS ARE STILL IN THE 30S...BUT MOST OF THE AREA IS
SEEING MID AND UPPER 40S OUT THERE FOR TEMPERATURES. WILL ALSO
ADJUST THESE PER THE LATEST SHORTBLEND GUIDANCE...CURRENT OBS...
AND TRENDS. THESE UPDATED GRIDS WILL BE SENT TO THE NDFD AND WEB
SERVERS.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 330 AM EST MON DEC 21 2015
08Z SFC ANALYSIS SHOWS A RELATIVELY TIGHT PRESSURE GRADIENT OVER
KENTUCKY BETWEEN HIGH PRESSURE RETREATING TO THE EAST WHILE DEEP
LOW PRESSURE MOVES INTO THE CENTRAL PLAINS. THIS GRADIENT...IN
ADDITION TO A LAYER OF THICK HIGH CLOUDS...IS SUPPORTING A MILDER
NIGHT ACROSS EAST KENTUCKY WITH READINGS IN MOST PLACES IN THE MID
40S. HOWEVER...SOME OF THE FAR EASTERN VALLEY ARE SHELTERED ENOUGH
THAT THEY HAVE MADE IT TO NEAR FREEZING. EXPECT THESE TO MIX OUT
BEFORE DAWN AND QUICKLY RISE INTO THE MID 40S WHEN THE WINDS PICK
UP FROM THE SOUTH AT 5 TO 10 MPH. MEANWHILE...DEW POINTS ARE
GENERALLY IN THE MID TO UPPER 20S THROUGHOUT EAST KENTUCKY EARLY
THIS MORNING WITH ANY RETURNS SHOWING UP ON RADAR TOO WEAK TO MAKE
IT TO THE SFC GIVEN THE DRY LOW LAYERS.
THE MODELS ARE IN GOOD AGREEMENT ALOFT THROUGH THE SHORT TERM
PORTION OF THE FORECAST. THEY ALL DEPICT A FLAT SOUTHEAST RIDGE
MOVING OFF TO THE EAST IN THE FACE OF A PAIR OF COMPACT SHORTWAVES
ROLLING PAST TO THE NORTHWEST OF THE JKL CWA. THE FIRST WILL BE
WEAKENING AS IT MOVES INTO THE NORTHERN OHIO VALLEY FROM THE
SOUTHERN PLAINS LATER TODAY...THOUGH SOME WEAK ENERGY IS MOVING
OVERHEAD CURRENTLY...AS WELL. AFTER A BRIEF REBUILD OF THE RIDGE
THE NEXT MID LEVEL WAVE CROSSES INTO THE CENTRAL OHIO VALLEY BY
DAWN TUESDAY...MAINTAINING ITS STRENGTH BETTER. THE RIDGE WILL
THEN HOLD ON TOUGH SOUTHEAST OF KENTUCKY WHILE THE BROAD SOUTHWEST
FLOW CONTINUES THROUGHOUT THE REGION AND ENERGY STARTS TO
RECHARGE TO THE SOUTHWEST. GIVEN THE MODEL AGREEMENT...HAVE AGAIN
FAVORED SOLUTIONS FROM THE HIGHER RESOLUTION HRRR AND NAM12...WITH
RESPECT TO WEATHER DETAILS.
SENSIBLE WEATHER WILL FEATURE A MILD START FOR MOST TODAY...ASIDE
FROM THE DEEP...SHELTERED VALLEYS IN THE EAST. AN
APPROACHING...BUT STALLING...COLD FRONT WILL PROVIDE A GLIDE PATH
FOR WAVES OF MOISTURES TO MOVE OVER EASTERN KENTUCKY DURING THE
SHORT TERM PORTION OF THE FORECAST AND BEYOND. LOOK FOR A WEAK ONE
TO PASS THROUGH LATER TODAY WITH A DECENT CHANCE FOR SHOWERS...
HOWEVER...AFTER A SHORT LULL...ANOTHER STRONGER AND WETTER WAVE
WILL PASS THROUGH TONIGHT INTO TUESDAY MORNING. PERSISTENT SOUTH
TO SOUTHWEST WINDS WILL KEEP TEMPERATURES WARM THROUGH THE MIDDLE
OF WEEK AND BEYOND...AS WELL. HIGHS TODAY WILL BE IN THE MID TO
UPPER 50S FOR MOST PLACES WITH LOW 60S ON TAP FOR TUESDAY. WE ARE
LOOKING FOR GENERALLY JUST A FEW TENTHS OF AN INCH OF RAINFALL
TODAY FOLLOWED BY A QUARTER TO A HALF AN INCH OF ACCUMULATION
TONIGHT WITH ANOTHER TENTH OR SO POSSIBLE DURING THE DAY TUESDAY.
FOR TEMPERATURES AND DEW POINTS...HAVE AGAIN STARTED WITH THE
SHORTBLEND GRIDS INTO TONIGHT FOLLOWED BY THE SUPERBLEND THROUGH
THE DAY TUESDAY. ONLY MADE MINOR CHANGES TO THE TEMPERATURES GIVEN
THE MOIST...CLOUDY...AND LIKELY WELL MIXED ENVIRONMENT IN PLACE
FOR THE SHORT TERM. AS FOR POPS...ENDED UP MOST SIMILAR TO THE
MET VALUES FOR TODAY INTO TUESDAY...THOUGH THE MAV IS NOT FAR
OFF...EITHER.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 320 AM EST MON DEC 21 2015
RECORD BREAKING WARMTH ALONG WITH SEVERAL PERIODS OF RAIN WILL
CONTINUE TO HIGHLIGHT THE WEATHER FORECAST AS WE HEAD TOWARDS AND
PAST CHRISTMAS.
THE PERIOD WILL START WITH A SHORTWAVE TROUGH MOVING UP THE SPINE OF
THE APPALACHIANS. WITH THE STALLED FRONTAL BOUNDARY TO OUR
NORTHWEST...WE SHOULD SEE MOISTURE INCREASE AS THIS SYSTEM SPREADS
NORTHWARD TUESDAY NIGHT. THIS WILL LEAD TO QUICKLY INCREASING RAIN
CHANCES. THE BULK OF THE RAIN SHOULD COME PRIOR TO DAYBREAK...WITH
THE WAVE DEPARTING QUICKLY TO THE NORTH. THIS WILL SET UP A
POTENTIAL DRY START TO THE DAY. DESPITE THE CLOUDS...TEMPERATURES
WILL LIKELY CLIMB CLOSE TO 70...LIKELY ECLIPSING A FEW RECORDS. RAIN
CHANCES WILL INCREASE AS WE HEAD INTO THE EVENING HOURS AS A
SHORTWAVE TROUGH PUSHES INTO THE GREAT LAKES...HELPING TO PUSH A
COLD FRONT ACROSS THE OHIO RIVER VALLEY. MODELS ARE SHOWING
CONSISTENT SIGNS OF WIDESPREAD RAIN AS THIS FRONT APPROACHES THE
AREA...SO WILL GO WITH CATEGORICAL RAIN CHANCES. IN ADDITION...MID
LEVEL LAPSE RATES WILL STEEPEN UP A BIT AHEAD OF THE FRONT...SO PLAN
TO INCLUDE A SLIGHT THREAT FOR SOME THUNDER THROUGH FROM WEDNESDAY
EVENING THROUGH THE OVERNIGHT HOURS. THE FRONT WILL LIKELY NOT MAKE
IT THROUGH THE AREA AND STALL BEFORE IT REACHES EASTERN
KENTUCKY...WITH RAIN CHANCES LIKELY LINGERING THROUGH MUCH OF
CHRISTMAS EVE...ESPECIALLY IN THE SOUTHEAST. RECORDS COULD
POTENTIALLY BE REACHED ON THURSDAY AS WELL IF THE RAIN EXITS EARLY
ENOUGH ALLOWING TIME FOR OUR TEMPERATURES TO RECOVER.
MODEL UNCERTAINTY GREATLY INCREASES CHRISTMAS MORNING THROUGH THE
FOLLOWING WEEKEND. WHILE CONFIDENCE IS LOW...GENERAL EVOLUTION
WOULD SUPPORT A WARM FRONT LIFTING NORTH ACROSS THE AREA ON
CHRISTMAS OR FRIDAY NIGHT...WITH ANOTHER SURGE OF WIDESPREAD
RAIN. THIS FRONT WILL THEN STALL OR CONTINUE MOVING NORTH THIS
WEEKEND WITH EVEN WARMER TEMPERATURES SPREADING NORTH FOR THE
WEEKEND. ONCE AGAIN...RECORD TEMPERATURES WILL BE POSSIBLE
SATURDAY THROUGH MONDAY AS WE COULD EASILY REACH THE MID TO UPPER
60S EACH DAY AND LIKELY END UP IN THE LOWER 70S FOR A FEW OF THE
DAYS IF CLOUDS DISSIPATE ENOUGH. DEPENDING HOW FAR NORTH THE FRONT
MOVES WILL DETERMINE HOW MUCH RAIN WE SEE OVER THE WEEKEND. ECMWF
LIFTS THE FRONT WELL NORTH...KEEPING MUCH OF KENTUCKY DRY FROM
LATE SATURDAY THROUGH MONDAY. GFS IS FARTHER SOUTH AND WOULD KEEP
SOME RAIN CHANCES OVER THE AREA. FOR NOW...WILL KEEP SOME RAIN
CHANCES IN THE FORECAST...BUT TREND THE FORECAST WARMER FOR THE
WEEKEND. IT LOOKS LIKE THE WARMTH MAY HOLD THROUGH THE END OF THE
YEAR.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1251 PM EST MON DEC 21 2015
CONDITIONS WERE OVERCAST BUT VFR AT TAF ISSUANCE. AN AREA OF
SHOWERS WAS ABOUT TO MOVE INTO THE REGION FROM THE NW...WITH
LOCALIZED MVFR. THIS AREA OF PRECIP WILL CONTINUE TO SINK SE
THROUGH THE AFTERNOON. A MORE SIGNIFICANT ROUND OF SHOWERS IS
EXPECTED TONIGHT...DEVELOPING FROM FROM SOUTH TO NORTH BETWEEN
ABOUT 00Z AND 06Z. A GENERALIZED REDUCTION TO MVFR IS EXPECTED
WITH THE SHOWERS TONIGHT...WITH SOME VARIATION AT TIMES. MUCH OF
THE PRECIPITATION SHOULD TAPER OFF TOWARD DAWN...BUT MVFR AND
LOCALIZED IFR CONDITIONS WILL LIKELY LINGER THROUGH THE REST OF
THE PERIOD.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HAL/GREIF
SHORT TERM...GREIF
LONG TERM...KAS
AVIATION...HAL
AREA FORECAST DISCUSSION
National Weather Service Paducah KY
1154 AM CST MON DEC 21 2015
.UPDATE...
Issued at 1154 AM CST MON DEC 21 2015
Have updated the public forecast this morning mainly to lower
PoPs, as the forcing is primarily in the very lowest layers, so
drizzle or light showers are the main precipitation types through
the remainder of the day. There may be an uptick in precipitation
over west Kentucky this evening, as an upper-level disturbance and
weak cold front move through the area.
Cannot rule out a stray TSRA over west Kentucky this afternoon,
but with low overcast skies, instability will be difficult to
come by. If there is any thunder it would be most likely over
west Kentucky as the cold front approaches later this evening.
Went through the night and into Tuesday morning on sky grids, as
it appears that very low overcast conditions will be the rule over
most of the area both ahead of and behind the wind shift.
The AVIATION section has been updated for the 18Z TAF issuance.
&&
.SHORT TERM...(Today through Wednesday night)
Issued at 305 AM CST MON DEC 21 2015
With a broad ridge in the Central Pacific and a series of
shortwaves expected to dig and rotate around a broad trough in the
southwest U.S. Unfortunately, this places the WFO PAH forecast
area in a broad southwesterly flow aloft, subject to frequent
instrusions of sharper lapse rates from passing upper level jet
dynamics and low level moist/warm advection scenarios.
The last 24 hours has seen a more dramatic (but not totally
unexpected) shift of better instability into the WFO PAH forecast
area. Enhanced convective activity over Western MO at this time is
just better evidence of the increased shear aloft and instability.
For the short term, blended the higher resolution HRRR explicit
model convective suite with the broader ECMWF/Canadian/GFS to
account for precipitation chances within and across several hours.
Added a wing of isolated thunderstorm chances riding up the
southeast MO foothills and into Southwest IL toward the I-64
corridor through the noon hour and the instability works northeast
with the approaching wave and slowing and weakening cold front.
The trend introduced yesterday of a break in the convective
activity late tonight and into Tuesday continues to be supported
as instability and moisture are lacking. However, this is short-
lived as the next shortwave (much more amplified in the 00z Monday Canadian
and GFS deterministic guidance versus the ECMWF) provides enough
ageostrophic response to lower pressures and reform the frontal
boundary, as well as sharpen moisture/theta-e advection back
northward late Tuesday afternoon and evening. The proximity of the
core of the stronger winds and instability should begin to support
sufficient updrafts for upright convection (thunderstorms). These
will advect northeast from Arkansas and Tennessee fairly quickly
by daybreak on Wednesday.
A strong enough gradient of moisture, shear, instability will be
in place Wednesday afternoon and evening to support a short
episode of enhanced convection and minor severe potential. Some of
this will be dependent on the degree of convection in the lower
Mississippi Valley impacting the degree and quality moisture
advection into the area.
Did not due a good job of temporal temperature trends in the light
of warm advection yesterday. Somewhat difficult to adequately
depict non-diurnal temperature trends. Temperatures on Wednesday
reflect some minor breaks in the cloud cover combined with strong
warm air advection. Could have gone a couple of degrees higher,
but timing of convection and cloud debris creates greater
uncertainty for seeing temperatures 25-30 degrees above normal at
this time.
.LONG TERM...(Thursday through Sunday)
Issued at 305 AM CST MON DEC 21 2015
An unsettled pattern is forecast in the long term. The 21/00z GFS
and 20/12z ECMWF were a pretty good match with the h5 pattern.
The new 21/00z ECMWF is also in line. Having said that, there have
been considerable run to run continuity issues prior, especially
with the evolution of a closed low over the SW U.S., and its effects
on the steering flow across our area, and resultant frontal
position, which is important with respect to PoPs. Therefore, the
uncertainty factor involved means keeping PoPs more broad brush
spatially with slightly lower values farther out in time.
For Thursday into Thursday evening (Christmas Eve), will carry a dry
forecast. The ECMWF continues to develop showers into southern
sections of the CWFA before daybreak Christmas. The other models do
not. Have slight chances to cover this early morning chance. PoPs
increase from south to north Friday through Friday night, with a
thunder chance also in play. Saturday into Sunday, the general
depiction is best chance PoPs will shift to NW sections of the CWFA
and lower across the SE (west KY) as the upper steering flow backs.
Will continue to carry thunder through the duration for the most
part as elevated instability and favorable mid level lapse rates
are maintained in both the ECMWF and GFS. Some locally heavy rain
cannot be ruled out, but still too soon as far as the details
including placement and amounts.
There continues to be a moderate spread with respect to temperatures
Friday and beyond, depending on the period. To minimize potential
errors, incorporated persistence with the latest Ensemble MOS
numbers. We incorporated Raw Model output where MOS is least likely
to deviate from its climo aspect as well. Overall, above normal
temperatures will be the rule.
&&
.AVIATION...
Issued at 1154 AM CST MON DEC 21 2015
IFR ceilings will gradually work eastward across the region this
afternoon, and then as a cold front approaches late this evening
and overnight, ceilings will lower to LIFR levels. The cold front
will have a brief wind shift to west northwest, but it will
basically wash out over the region early Tuesday and a southeast
wind will develop late Tuesday morning. Could see periodic MVFR
light rain this afternoon mainly at KEVV and KOWB, but the best
chance of precipitation appears to be just ahead of the cold front
late this evening into the overnight hours when drizzle or shower
activity will be possible. Cannot even rule out a TS at KOWB.
Ceilings should improve quickly by late morning.
&&
.PAH Watches/Warnings/Advisories...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
UPDATE...DRS
SHORT TERM...Smith
LONG TERM...CN
AVIATION...DRS
AREA FORECAST DISCUSSION
NWS JACKSON KY
1251 PM EST MON DEC 21 2015
.UPDATE...
ISSUED AT 1125 AM EST MON DEC 21 2015
FIRST ROUND OF PRECIP HAS EXITED TO THE EAST...AND ANOTHER ROUND
IS HEADING IN FROM THE WEST. HAVE MADE MINOR UPDATES TO GRIDS FOR
THE TIMING. WITH CLOUDS AND PRECIP...TEMPS ARE RISING A BIT SLOWER
THAN WAS FORECAST. HAVE KNOCKED DOWN AFTERNOON HIGHS SLIGHTLY.
UPDATE ISSUED AT 846 AM EST MON DEC 21 2015
AN AREA OF LIGHT RAIN IS MOVING EAST ACROSS THE REGION...BUT IS
GRADUALLY DIMINISHING AS IT MOVES INTO DRIER AIR. HAVE UPDATED THE
GRIDS FOR TIMING OF THIS PRECIP. HAVE ALSO BLENDED EARLY MORNING
OBSERVED TEMPS/DEW POINTS INTO THE DAYTIME FORECAST.
UPDATE ISSUED AT 620 AM EST MON DEC 21 2015
A LINE OF MEASURABLE RAIN SHOWERS IS MAKING STEADY PROGRESS
THROUGH CENTRAL KENTUCKY AND WILL BE IN HERE SHORTLY AFTER 12Z.
WILL UPDATED THE POPS TO BETTER TIME THIS FEATURE. ALSO...SOME OF
THE EASTERN VALLEYS ARE STILL IN THE 30S...BUT MOST OF THE AREA IS
SEEING MID AND UPPER 40S OUT THERE FOR TEMPERATURES. WILL ALSO
ADJUST THESE PER THE LATEST SHORTBLEND GUIDANCE...CURRENT OBS...
AND TRENDS. THESE UPDATED GRIDS WILL BE SENT TO THE NDFD AND WEB
SERVERS.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 330 AM EST MON DEC 21 2015
08Z SFC ANALYSIS SHOWS A RELATIVELY TIGHT PRESSURE GRADIENT OVER
KENTUCKY BETWEEN HIGH PRESSURE RETREATING TO THE EAST WHILE DEEP
LOW PRESSURE MOVES INTO THE CENTRAL PLAINS. THIS GRADIENT...IN
ADDITION TO A LAYER OF THICK HIGH CLOUDS...IS SUPPORTING A MILDER
NIGHT ACROSS EAST KENTUCKY WITH READINGS IN MOST PLACES IN THE MID
40S. HOWEVER...SOME OF THE FAR EASTERN VALLEY ARE SHELTERED ENOUGH
THAT THEY HAVE MADE IT TO NEAR FREEZING. EXPECT THESE TO MIX OUT
BEFORE DAWN AND QUICKLY RISE INTO THE MID 40S WHEN THE WINDS PICK
UP FROM THE SOUTH AT 5 TO 10 MPH. MEANWHILE...DEW POINTS ARE
GENERALLY IN THE MID TO UPPER 20S THROUGHOUT EAST KENTUCKY EARLY
THIS MORNING WITH ANY RETURNS SHOWING UP ON RADAR TOO WEAK TO MAKE
IT TO THE SFC GIVEN THE DRY LOW LAYERS.
THE MODELS ARE IN GOOD AGREEMENT ALOFT THROUGH THE SHORT TERM
PORTION OF THE FORECAST. THEY ALL DEPICT A FLAT SOUTHEAST RIDGE
MOVING OFF TO THE EAST IN THE FACE OF A PAIR OF COMPACT SHORTWAVES
ROLLING PAST TO THE NORTHWEST OF THE JKL CWA. THE FIRST WILL BE
WEAKENING AS IT MOVES INTO THE NORTHERN OHIO VALLEY FROM THE
SOUTHERN PLAINS LATER TODAY...THOUGH SOME WEAK ENERGY IS MOVING
OVERHEAD CURRENTLY...AS WELL. AFTER A BRIEF REBUILD OF THE RIDGE
THE NEXT MID LEVEL WAVE CROSSES INTO THE CENTRAL OHIO VALLEY BY
DAWN TUESDAY...MAINTAINING ITS STRENGTH BETTER. THE RIDGE WILL
THEN HOLD ON TOUGH SOUTHEAST OF KENTUCKY WHILE THE BROAD SOUTHWEST
FLOW CONTINUES THROUGHOUT THE REGION AND ENERGY STARTS TO
RECHARGE TO THE SOUTHWEST. GIVEN THE MODEL AGREEMENT...HAVE AGAIN
FAVORED SOLUTIONS FROM THE HIGHER RESOLUTION HRRR AND NAM12...WITH
RESPECT TO WEATHER DETAILS.
SENSIBLE WEATHER WILL FEATURE A MILD START FOR MOST TODAY...ASIDE
FROM THE DEEP...SHELTERED VALLEYS IN THE EAST. AN
APPROACHING...BUT STALLING...COLD FRONT WILL PROVIDE A GLIDE PATH
FOR WAVES OF MOISTURES TO MOVE OVER EASTERN KENTUCKY DURING THE
SHORT TERM PORTION OF THE FORECAST AND BEYOND. LOOK FOR A WEAK ONE
TO PASS THROUGH LATER TODAY WITH A DECENT CHANCE FOR SHOWERS...
HOWEVER...AFTER A SHORT LULL...ANOTHER STRONGER AND WETTER WAVE
WILL PASS THROUGH TONIGHT INTO TUESDAY MORNING. PERSISTENT SOUTH
TO SOUTHWEST WINDS WILL KEEP TEMPERATURES WARM THROUGH THE MIDDLE
OF WEEK AND BEYOND...AS WELL. HIGHS TODAY WILL BE IN THE MID TO
UPPER 50S FOR MOST PLACES WITH LOW 60S ON TAP FOR TUESDAY. WE ARE
LOOKING FOR GENERALLY JUST A FEW TENTHS OF AN INCH OF RAINFALL
TODAY FOLLOWED BY A QUARTER TO A HALF AN INCH OF ACCUMULATION
TONIGHT WITH ANOTHER TENTH OR SO POSSIBLE DURING THE DAY TUESDAY.
FOR TEMPERATURES AND DEW POINTS...HAVE AGAIN STARTED WITH THE
SHORTBLEND GRIDS INTO TONIGHT FOLLOWED BY THE SUPERBLEND THROUGH
THE DAY TUESDAY. ONLY MADE MINOR CHANGES TO THE TEMPERATURES GIVEN
THE MOIST...CLOUDY...AND LIKELY WELL MIXED ENVIRONMENT IN PLACE
FOR THE SHORT TERM. AS FOR POPS...ENDED UP MOST SIMILAR TO THE
MET VALUES FOR TODAY INTO TUESDAY...THOUGH THE MAV IS NOT FAR
OFF...EITHER.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 320 AM EST MON DEC 21 2015
RECORD BREAKING WARMTH ALONG WITH SEVERAL PERIODS OF RAIN WILL
CONTINUE TO HIGHLIGHT THE WEATHER FORECAST AS WE HEAD TOWARDS AND
PAST CHRISTMAS.
THE PERIOD WILL START WITH A SHORTWAVE TROUGH MOVING UP THE SPINE OF
THE APPALACHIANS. WITH THE STALLED FRONTAL BOUNDARY TO OUR
NORTHWEST...WE SHOULD SEE MOISTURE INCREASE AS THIS SYSTEM SPREADS
NORTHWARD TUESDAY NIGHT. THIS WILL LEAD TO QUICKLY INCREASING RAIN
CHANCES. THE BULK OF THE RAIN SHOULD COME PRIOR TO DAYBREAK...WITH
THE WAVE DEPARTING QUICKLY TO THE NORTH. THIS WILL SET UP A
POTENTIAL DRY START TO THE DAY. DESPITE THE CLOUDS...TEMPERATURES
WILL LIKELY CLIMB CLOSE TO 70...LIKELY ECLIPSING A FEW RECORDS. RAIN
CHANCES WILL INCREASE AS WE HEAD INTO THE EVENING HOURS AS A
SHORTWAVE TROUGH PUSHES INTO THE GREAT LAKES...HELPING TO PUSH A
COLD FRONT ACROSS THE OHIO RIVER VALLEY. MODELS ARE SHOWING
CONSISTENT SIGNS OF WIDESPREAD RAIN AS THIS FRONT APPROACHES THE
AREA...SO WILL GO WITH CATEGORICAL RAIN CHANCES. IN ADDITION...MID
LEVEL LAPSE RATES WILL STEEPEN UP A BIT AHEAD OF THE FRONT...SO PLAN
TO INCLUDE A SLIGHT THREAT FOR SOME THUNDER THROUGH FROM WEDNESDAY
EVENING THROUGH THE OVERNIGHT HOURS. THE FRONT WILL LIKELY NOT MAKE
IT THROUGH THE AREA AND STALL BEFORE IT REACHES EASTERN
KENTUCKY...WITH RAIN CHANCES LIKELY LINGERING THROUGH MUCH OF
CHRISTMAS EVE...ESPECIALLY IN THE SOUTHEAST. RECORDS COULD
POTENTIALLY BE REACHED ON THURSDAY AS WELL IF THE RAIN EXITS EARLY
ENOUGH ALLOWING TIME FOR OUR TEMPERATURES TO RECOVER.
MODEL UNCERTAINTY GREATLY INCREASES CHRISTMAS MORNING THROUGH THE
FOLLOWING WEEKEND. WHILE CONFIDENCE IS LOW...GENERAL EVOLUTION
WOULD SUPPORT A WARM FRONT LIFTING NORTH ACROSS THE AREA ON
CHRISTMAS OR FRIDAY NIGHT...WITH ANOTHER SURGE OF WIDESPREAD
RAIN. THIS FRONT WILL THEN STALL OR CONTINUE MOVING NORTH THIS
WEEKEND WITH EVEN WARMER TEMPERATURES SPREADING NORTH FOR THE
WEEKEND. ONCE AGAIN...RECORD TEMPERATURES WILL BE POSSIBLE
SATURDAY THROUGH MONDAY AS WE COULD EASILY REACH THE MID TO UPPER
60S EACH DAY AND LIKELY END UP IN THE LOWER 70S FOR A FEW OF THE
DAYS IF CLOUDS DISSIPATE ENOUGH. DEPENDING HOW FAR NORTH THE FRONT
MOVES WILL DETERMINE HOW MUCH RAIN WE SEE OVER THE WEEKEND. ECMWF
LIFTS THE FRONT WELL NORTH...KEEPING MUCH OF KENTUCKY DRY FROM
LATE SATURDAY THROUGH MONDAY. GFS IS FARTHER SOUTH AND WOULD KEEP
SOME RAIN CHANCES OVER THE AREA. FOR NOW...WILL KEEP SOME RAIN
CHANCES IN THE FORECAST...BUT TREND THE FORECAST WARMER FOR THE
WEEKEND. IT LOOKS LIKE THE WARMTH MAY HOLD THROUGH THE END OF THE
YEAR.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1251 PM EST MON DEC 21 2015
CONDITIONS WERE OVERCAST BUT VFR AT TAF ISSUANCE. AN AREA OF
SHOWERS WAS ABOUT TO MOVE INTO THE REGION FROM THE NW...WITH
LOCALIZED MVFR. THIS AREA OF PRECIP WILL CONTINUE TO SINK SE
THROUGH THE AFTERNOON. A MORE SIGNIFICANT ROUND OF SHOWERS IS
EXPECTED TONIGHT...DEVELOPING FROM FROM SOUTH TO NORTH BETWEEN
ABOUT 00Z AND 06Z. A GENERALIZED REDUCTION TO MVFR IS EXPECTED
WITH THE SHOWERS TONIGHT...WITH SOME VARIATION AT TIMES. MUCH OF
THE PRECIPITATION SHOULD TAPER OFF TOWARD DAWN...BUT MVFR AND
LOCALIZED IFR CONDITIONS WILL LIKELY LINGER THROUGH THE REST OF
THE PERIOD.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HAL/GREIF
SHORT TERM...GREIF
LONG TERM...KAS
AVIATION...HAL
AREA FORECAST DISCUSSION
NWS JACKSON KY
1125 AM EST MON DEC 21 2015
.UPDATE...
ISSUED AT 1125 AM EST MON DEC 21 2015
FIRST ROUND OF PRECIP HAS EXITED TO THE EAST...AND ANOTHER ROUND
IS HEADING IN FROM THE WEST. HAVE MADE MINOR UPDATES TO GRIDS FOR
THE TIMING. WITH CLOUDS AND PRECIP...TEMPS ARE RISING A BIT SLOWER
THAN WAS FORECAST. HAVE KNOCKED DOWN AFTERNOON HIGHS SLIGHTLY.
UPDATE ISSUED AT 846 AM EST MON DEC 21 2015
AN AREA OF LIGHT RAIN IS MOVING EAST ACROSS THE REGION...BUT IS
GRADUALLY DIMINISHING AS IT MOVES INTO DRIER AIR. HAVE UPDATED THE
GRIDS FOR TIMING OF THIS PRECIP. HAVE ALSO BLENDED EARLY MORNING
OBSERVED TEMPS/DEW POINTS INTO THE DAYTIME FORECAST.
UPDATE ISSUED AT 620 AM EST MON DEC 21 2015
A LINE OF MEASURABLE RAIN SHOWERS IS MAKING STEADY PROGRESS
THROUGH CENTRAL KENTUCKY AND WILL BE IN HERE SHORTLY AFTER 12Z.
WILL UPDATED THE POPS TO BETTER TIME THIS FEATURE. ALSO...SOME OF
THE EASTERN VALLEYS ARE STILL IN THE 30S...BUT MOST OF THE AREA IS
SEEING MID AND UPPER 40S OUT THERE FOR TEMPERATURES. WILL ALSO
ADJUST THESE PER THE LATEST SHORTBLEND GUIDANCE...CURRENT OBS...
AND TRENDS. THESE UPDATED GRIDS WILL BE SENT TO THE NDFD AND WEB
SERVERS.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 330 AM EST MON DEC 21 2015
08Z SFC ANALYSIS SHOWS A RELATIVELY TIGHT PRESSURE GRADIENT OVER
KENTUCKY BETWEEN HIGH PRESSURE RETREATING TO THE EAST WHILE DEEP
LOW PRESSURE MOVES INTO THE CENTRAL PLAINS. THIS GRADIENT...IN
ADDITION TO A LAYER OF THICK HIGH CLOUDS...IS SUPPORTING A MILDER
NIGHT ACROSS EAST KENTUCKY WITH READINGS IN MOST PLACES IN THE MID
40S. HOWEVER...SOME OF THE FAR EASTERN VALLEY ARE SHELTERED ENOUGH
THAT THEY HAVE MADE IT TO NEAR FREEZING. EXPECT THESE TO MIX OUT
BEFORE DAWN AND QUICKLY RISE INTO THE MID 40S WHEN THE WINDS PICK
UP FROM THE SOUTH AT 5 TO 10 MPH. MEANWHILE...DEW POINTS ARE
GENERALLY IN THE MID TO UPPER 20S THROUGHOUT EAST KENTUCKY EARLY
THIS MORNING WITH ANY RETURNS SHOWING UP ON RADAR TOO WEAK TO MAKE
IT TO THE SFC GIVEN THE DRY LOW LAYERS.
THE MODELS ARE IN GOOD AGREEMENT ALOFT THROUGH THE SHORT TERM
PORTION OF THE FORECAST. THEY ALL DEPICT A FLAT SOUTHEAST RIDGE
MOVING OFF TO THE EAST IN THE FACE OF A PAIR OF COMPACT SHORTWAVES
ROLLING PAST TO THE NORTHWEST OF THE JKL CWA. THE FIRST WILL BE
WEAKENING AS IT MOVES INTO THE NORTHERN OHIO VALLEY FROM THE
SOUTHERN PLAINS LATER TODAY...THOUGH SOME WEAK ENERGY IS MOVING
OVERHEAD CURRENTLY...AS WELL. AFTER A BRIEF REBUILD OF THE RIDGE
THE NEXT MID LEVEL WAVE CROSSES INTO THE CENTRAL OHIO VALLEY BY
DAWN TUESDAY...MAINTAINING ITS STRENGTH BETTER. THE RIDGE WILL
THEN HOLD ON TOUGH SOUTHEAST OF KENTUCKY WHILE THE BROAD SOUTHWEST
FLOW CONTINUES THROUGHOUT THE REGION AND ENERGY STARTS TO
RECHARGE TO THE SOUTHWEST. GIVEN THE MODEL AGREEMENT...HAVE AGAIN
FAVORED SOLUTIONS FROM THE HIGHER RESOLUTION HRRR AND NAM12...WITH
RESPECT TO WEATHER DETAILS.
SENSIBLE WEATHER WILL FEATURE A MILD START FOR MOST TODAY...ASIDE
FROM THE DEEP...SHELTERED VALLEYS IN THE EAST. AN
APPROACHING...BUT STALLING...COLD FRONT WILL PROVIDE A GLIDE PATH
FOR WAVES OF MOISTURES TO MOVE OVER EASTERN KENTUCKY DURING THE
SHORT TERM PORTION OF THE FORECAST AND BEYOND. LOOK FOR A WEAK ONE
TO PASS THROUGH LATER TODAY WITH A DECENT CHANCE FOR SHOWERS...
HOWEVER...AFTER A SHORT LULL...ANOTHER STRONGER AND WETTER WAVE
WILL PASS THROUGH TONIGHT INTO TUESDAY MORNING. PERSISTENT SOUTH
TO SOUTHWEST WINDS WILL KEEP TEMPERATURES WARM THROUGH THE MIDDLE
OF WEEK AND BEYOND...AS WELL. HIGHS TODAY WILL BE IN THE MID TO
UPPER 50S FOR MOST PLACES WITH LOW 60S ON TAP FOR TUESDAY. WE ARE
LOOKING FOR GENERALLY JUST A FEW TENTHS OF AN INCH OF RAINFALL
TODAY FOLLOWED BY A QUARTER TO A HALF AN INCH OF ACCUMULATION
TONIGHT WITH ANOTHER TENTH OR SO POSSIBLE DURING THE DAY TUESDAY.
FOR TEMPERATURES AND DEW POINTS...HAVE AGAIN STARTED WITH THE
SHORTBLEND GRIDS INTO TONIGHT FOLLOWED BY THE SUPERBLEND THROUGH
THE DAY TUESDAY. ONLY MADE MINOR CHANGES TO THE TEMPERATURES GIVEN
THE MOIST...CLOUDY...AND LIKELY WELL MIXED ENVIRONMENT IN PLACE
FOR THE SHORT TERM. AS FOR POPS...ENDED UP MOST SIMILAR TO THE
MET VALUES FOR TODAY INTO TUESDAY...THOUGH THE MAV IS NOT FAR
OFF...EITHER.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 320 AM EST MON DEC 21 2015
RECORD BREAKING WARMTH ALONG WITH SEVERAL PERIODS OF RAIN WILL
CONTINUE TO HIGHLIGHT THE WEATHER FORECAST AS WE HEAD TOWARDS AND
PAST CHRISTMAS.
THE PERIOD WILL START WITH A SHORTWAVE TROUGH MOVING UP THE SPINE OF
THE APPALACHIANS. WITH THE STALLED FRONTAL BOUNDARY TO OUR
NORTHWEST...WE SHOULD SEE MOISTURE INCREASE AS THIS SYSTEM SPREADS
NORTHWARD TUESDAY NIGHT. THIS WILL LEAD TO QUICKLY INCREASING RAIN
CHANCES. THE BULK OF THE RAIN SHOULD COME PRIOR TO DAYBREAK...WITH
THE WAVE DEPARTING QUICKLY TO THE NORTH. THIS WILL SET UP A
POTENTIAL DRY START TO THE DAY. DESPITE THE CLOUDS...TEMPERATURES
WILL LIKELY CLIMB CLOSE TO 70...LIKELY ECLIPSING A FEW RECORDS. RAIN
CHANCES WILL INCREASE AS WE HEAD INTO THE EVENING HOURS AS A
SHORTWAVE TROUGH PUSHES INTO THE GREAT LAKES...HELPING TO PUSH A
COLD FRONT ACROSS THE OHIO RIVER VALLEY. MODELS ARE SHOWING
CONSISTENT SIGNS OF WIDESPREAD RAIN AS THIS FRONT APPROACHES THE
AREA...SO WILL GO WITH CATEGORICAL RAIN CHANCES. IN ADDITION...MID
LEVEL LAPSE RATES WILL STEEPEN UP A BIT AHEAD OF THE FRONT...SO PLAN
TO INCLUDE A SLIGHT THREAT FOR SOME THUNDER THROUGH FROM WEDNESDAY
EVENING THROUGH THE OVERNIGHT HOURS. THE FRONT WILL LIKELY NOT MAKE
IT THROUGH THE AREA AND STALL BEFORE IT REACHES EASTERN
KENTUCKY...WITH RAIN CHANCES LIKELY LINGERING THROUGH MUCH OF
CHRISTMAS EVE...ESPECIALLY IN THE SOUTHEAST. RECORDS COULD
POTENTIALLY BE REACHED ON THURSDAY AS WELL IF THE RAIN EXITS EARLY
ENOUGH ALLOWING TIME FOR OUR TEMPERATURES TO RECOVER.
MODEL UNCERTAINTY GREATLY INCREASES CHRISTMAS MORNING THROUGH THE
FOLLOWING WEEKEND. WHILE CONFIDENCE IS LOW...GENERAL EVOLUTION
WOULD SUPPORT A WARM FRONT LIFTING NORTH ACROSS THE AREA ON
CHRISTMAS OR FRIDAY NIGHT...WITH ANOTHER SURGE OF WIDESPREAD
RAIN. THIS FRONT WILL THEN STALL OR CONTINUE MOVING NORTH THIS
WEEKEND WITH EVEN WARMER TEMPERATURES SPREADING NORTH FOR THE
WEEKEND. ONCE AGAIN...RECORD TEMPERATURES WILL BE POSSIBLE
SATURDAY THROUGH MONDAY AS WE COULD EASILY REACH THE MID TO UPPER
60S EACH DAY AND LIKELY END UP IN THE LOWER 70S FOR A FEW OF THE
DAYS IF CLOUDS DISSIPATE ENOUGH. DEPENDING HOW FAR NORTH THE FRONT
MOVES WILL DETERMINE HOW MUCH RAIN WE SEE OVER THE WEEKEND. ECMWF
LIFTS THE FRONT WELL NORTH...KEEPING MUCH OF KENTUCKY DRY FROM
LATE SATURDAY THROUGH MONDAY. GFS IS FARTHER SOUTH AND WOULD KEEP
SOME RAIN CHANCES OVER THE AREA. FOR NOW...WILL KEEP SOME RAIN
CHANCES IN THE FORECAST...BUT TREND THE FORECAST WARMER FOR THE
WEEKEND. IT LOOKS LIKE THE WARMTH MAY HOLD THROUGH THE END OF THE
YEAR.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 645 AM EST MON DEC 21 2015
AN APPROACHING COLD FRONT WILL BRING IN A DECK OF MID LEVEL CIGS
EARLY IN THE PERIOD. BETWEEN 12 AND 14Z...THOUGH...RAIN SHOWERS
WILL BEGIN MOVING INTO THE WESTERN TAF SITES...SPREADING EASTWARD
AS CLOUDS CONTINUE TO LOWER TO NEAR MVFR CONDITIONS. EXPECT RAIN
CHANCES AND MVFR CIGS TO INCREASE THROUGHOUT THE REST OF THE
AFTERNOON...WITH PREVAILING RAIN EXPECTED BETWEEN 14 AND 19Z.
AFTER A LULL ANOTHER ROUND OF SHOWERS WILL BE POSSIBLE LATER
TONIGHT. WINDS WILL INCREASE FROM THE SOUTH TO SOUTHWEST THIS
MORNING AND GUST UP TO 20 KNOTS THE BULK OF THE DAY...ESPECIALLY
DURING ANY OF THE HEAVIER RAIN SHOWERS.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HAL
SHORT TERM...GREIF
LONG TERM...KAS
AVIATION...GREIF
AREA FORECAST DISCUSSION
NWS JACKSON KY
846 AM EST MON DEC 21 2015
.UPDATE...
ISSUED AT 846 AM EST MON DEC 21 2015
AN AREA OF LIGHT RAIN IS MOVING EAST ACROSS THE REGION...BUT IS
GRADUALLY DIMINISHING AS IT MOVES INTO DRIER AIR. HAVE UPDATED THE
GRIDS FOR TIMING OF THIS PRECIP. HAVE ALSO BLENDED EARLY MORNING
OBSERVED TEMPS/DEW POINTS INTO THE DAYTIME FORECAST.
UPDATE ISSUED AT 620 AM EST MON DEC 21 2015
A LINE OF MEASURABLE RAIN SHOWERS IS MAKING STEADY PROGRESS
THROUGH CENTRAL KENTUCKY AND WILL BE IN HERE SHORTLY AFTER 12Z.
WILL UPDATED THE POPS TO BETTER TIME THIS FEATURE. ALSO...SOME OF
THE EASTERN VALLEYS ARE STILL IN THE 30S...BUT MOST OF THE AREA IS
SEEING MID AND UPPER 40S OUT THERE FOR TEMPERATURES. WILL ALSO
ADJUST THESE PER THE LATEST SHORTBLEND GUIDANCE...CURRENT OBS...
AND TRENDS. THESE UPDATED GRIDS WILL BE SENT TO THE NDFD AND WEB
SERVERS.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 330 AM EST MON DEC 21 2015
08Z SFC ANALYSIS SHOWS A RELATIVELY TIGHT PRESSURE GRADIENT OVER
KENTUCKY BETWEEN HIGH PRESSURE RETREATING TO THE EAST WHILE DEEP
LOW PRESSURE MOVES INTO THE CENTRAL PLAINS. THIS GRADIENT...IN
ADDITION TO A LAYER OF THICK HIGH CLOUDS...IS SUPPORTING A MILDER
NIGHT ACROSS EAST KENTUCKY WITH READINGS IN MOST PLACES IN THE MID
40S. HOWEVER...SOME OF THE FAR EASTERN VALLEY ARE SHELTERED ENOUGH
THAT THEY HAVE MADE IT TO NEAR FREEZING. EXPECT THESE TO MIX OUT
BEFORE DAWN AND QUICKLY RISE INTO THE MID 40S WHEN THE WINDS PICK
UP FROM THE SOUTH AT 5 TO 10 MPH. MEANWHILE...DEWPOINTS ARE
GENERALLY IN THE MID TO UPPER 20S THROUGHOUT EAST KENTUCKY EARLY
THIS MORNING WITH ANY RETURNS SHOWING UP ON RADAR TOO WEAK TO MAKE
IT TO THE SFC GIVEN THE DRY LOW LAYERS.
THE MODELS ARE IN GOOD AGREEMENT ALOFT THROUGH THE SHORT TERM
PORTION OF THE FORECAST. THEY ALL DEPICT A FLAT SOUTHEAST RIDGE
MOVING OFF TO THE EAST IN THE FACE OF A PAIR OF COMPACT SHORTWAVES
ROLLING PAST TO THE NORTHWEST OF THE JKL CWA. THE FIRST WILL BE
WEAKENING AS IT MOVES INTO THE NORTHERN OHIO VALLEY FROM THE
SOUTHERN PLAINS LATER TODAY...THOUGH SOME WEAK ENERGY IS MOVING
OVERHEAD CURRENTLY...AS WELL. AFTER A BRIEF REBUILD OF THE RIDGE
THE NEXT MID LEVEL WAVE CROSSES INTO THE CENTRAL OHIO VALLEY BY
DAWN TUESDAY...MAINTAINING ITS STRENGTH BETTER. THE RIDGE WILL
THEN HOLD ON TOUGH SOUTHEAST OF KENTUCKY WHILE THE BROAD SOUTHWEST
FLOW CONTINUES THROUGHOUT THE REGION AND ENERGY STARTS TO
RECHARGE TO THE SOUTHWEST. GIVEN THE MODEL AGREEMENT...HAVE AGAIN
FAVORED SOLUTIONS FROM THE HIGHER RESOLUTION HRRR AND NAM12...WITH
RESPECT TO WEATHER DETAILS.
SENSIBLE WEATHER WILL FEATURE A MILD START FOR MOST TODAY...ASIDE
FROM THE DEEP...SHELTERED VALLEYS IN THE EAST. AN
APPROACHING...BUT STALLING...COLD FRONT WILL PROVIDE A GLIDE PATH
FOR WAVES OF MOISTURES TO MOVE OVER EASTERN KENTUCKY DURING THE
SHORT TERM PORTION OF THE FORECAST AND BEYOND. LOOK FOR A WEAK ONE
TO PASS THROUGH LATER TODAY WITH A DECENT CHANCE FOR SHOWERS...
HOWEVER...AFTER A SHORT LULL...ANOTHER STRONGER AND WETTER WAVE
WILL PASS THROUGH TONIGHT INTO TUESDAY MORNING. PERSISTENT SOUTH
TO SOUTHWEST WINDS WILL KEEP TEMPERATURES WARM THROUGH THE MIDDLE
OF WEEK AND BEYOND...AS WELL. HIGHS TODAY WILL BE IN THE MID TO
UPPER 50S FOR MOST PLACES WITH LOW 60S ON TAP FOR TUESDAY. WE ARE
LOOKING FOR GENERALLY JUST A FEW TENTHS OF AN INCH OF RAINFALL
TODAY FOLLOWED BY A QUARTER TO A HALF AN INCH OF ACCUMULATION
TONIGHT WITH ANOTHER TENTH OR SO POSSIBLE DURING THE DAY TUESDAY.
FOR TEMPERATURES AND DEWPOINTS...HAVE AGAIN STARTED WITH THE
SHORTBLEND GRIDS INTO TONIGHT FOLLOWED BY THE SUPERBLEND THROUGH
THE DAY TUESDAY. ONLY MADE MINOR CHANGES TO THE TEMPERATURES GIVEN
THE MOIST...CLOUDY...AND LIKELY WELL MIXED ENVIRONMENT IN PLACE
FOR THE SHORT TERM. AS FOR POPS...ENDED UP MOST SIMILAR TO THE
MET VALUES FOR TODAY INTO TUESDAY...THOUGH THE MAV IS NOT FAR
OFF...EITHER.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 320 AM EST MON DEC 21 2015
RECORD BREAKING WARMTH ALONG WITH SEVERAL PERIODS OF RAIN WILL
CONTINUE TO HIGHLIGHT THE WEATHER FORECAST AS WE HEAD TOWARDS AND
PAST CHRISTMAS.
THE PERIOD WILL START WITH A SHORTWAVE TROUGH MOVING UP THE SPINE OF
THE APPALACHIANS. WITH THE STALLED FRONTAL BOUNDARY TO OUR
NORTHWEST...WE SHOULD SEE MOISTURE INCREASE AS THIS SYSTEM SPREADS
NORTHWARD TUESDAY NIGHT. THIS WILL LEAD TO QUICKLY INCREASING RAIN
CHANCES. THE BULK OF THE RAIN SHOULD COME PRIOR TO DAYBREAK...WITH
THE WAVE DEPARTING QUICKLY TO THE NORTH. THIS WILL SET UP A
POTENTIAL DRY START TO THE DAY. DESPITE THE CLOUDS...TEMPERATURES
WILL LIKELY CLIMB CLOSE TO 70...LIKELY ECLIPSING A FEW RECORDS. RAIN
CHANCES WILL INCREASE AS WE HEAD INTO THE EVENING HOURS AS A
SHORTWAVE TROUGH PUSHES INTO THE GREAT LAKES...HELPING TO PUSH A
COLD FRONT ACROSS THE OHIO RIVER VALLEY. MODELS ARE SHOWING
CONSISTENT SIGNS OF WIDESPREAD RAIN AS THIS FRONT APPROACHES THE
AREA...SO WILL GO WITH CATEGORICAL RAIN CHANCES. IN ADDITION...MID
LEVEL LAPSE RATES WILL STEEPEN UP A BIT AHEAD OF THE FRONT...SO PLAN
TO INCLUDE A SLIGHT THREAT FOR SOME THUNDER THROUGH FROM WEDNESDAY
EVENING THROUGH THE OVERNIGHT HOURS. THE FRONT WILL LIKELY NOT MAKE
IT THROUGH THE AREA AND STALL BEFORE IT REACHES EASTERN
KENTUCKY...WITH RAIN CHANCES LIKELY LINGERING THROUGH MUCH OF
CHRISTMAS EVE...ESPECIALLY IN THE SOUTHEAST. RECORDS COULD
POTENTIALLY BE REACHED ON THURSDAY AS WELL IF THE RAIN EXITS EARLY
ENOUGH ALLOWING TIME FOR OUR TEMPERATURES TO RECOVER.
MODEL UNCERTAINTY GREATLY INCREASES CHRISTMAS MORNING THROUGH THE
FOLLOWING WEEKEND. WHILE CONFIDENCE IS LOW...GENERAL EVOLUTION
WOULD SUPPORT A WARM FRONT LIFTING NORTH ACROSS THE AREA ON
CHRISTMAS OR FRIDAY NIGHT...WITH ANOTHER SURGE OF WIDESPREAD RAIN.
THIS FRONT WILL THEN STALL OR CONTINUE MOVING NORTH THIS WEEKEND
WITH EVEN WARMER TEMPERATURES SPREADING NORTH FOR THE WEEKEND. ONCE
AGAIN...RECORD TEMPERATURES WILL BE POSSIBLE SATURDAY THROUGH MONDAY
AS WE COULD EASILY REACH THE MID TO UPPER 60S EACH DAY AND LIKELY
END UP IN THE LOWER 70S FOR A FEW OF THE DAYS IF CLOUDS DISSIPATE
ENOUGH. DEPENDING HOW FAR NORTH THE FRONT MOVES WILL DETERMINE HOW
MUCH RAIN WE SEE OVER THE WEEKEND. ECMWF LIFTS THE FRONT WELL
NORTH...KEEPING MUCH OF KENTUCKY DRY FROM LATE SATURDAY THROUGH
MONDAY. GFS IS FARTHER SOUTH AND WOULD KEEP SOME RAIN CHANCES OVER
THE AREA. FOR NOW...WILL KEEP SOME RAIN CHANCES IN THE
FORECAST...BUT TREND THE FORECAST WARMER FOR THE WEEKEND. IT LOOKS
LIKE THE WARMTH MAY HOLD THROUGH THE END OF THE YEAR.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 645 AM EST MON DEC 21 2015
AN APPROACHING COLD FRONT WILL BRING IN A DECK OF MID LEVEL CIGS
EARLY IN THE PERIOD. BETWEEN 12 AND 14Z...THOUGH...RAIN SHOWERS
WILL BEGIN MOVING INTO THE WESTERN TAF SITES...SPREADING EASTWARD
AS CLOUDS CONTINUE TO LOWER TO NEAR MVFR CONDITIONS. EXPECT RAIN
CHANCES AND MVFR CIGS TO INCREASE THROUGHOUT THE REST OF THE
AFTERNOON...WITH PREVAILING RAIN EXPECTED BETWEEN 14 AND 19Z.
AFTER A LULL ANOTHER ROUND OF SHOWERS WILL BE POSSIBLE LATER
TONIGHT. WINDS WILL INCREASE FROM THE SOUTH TO SOUTHWEST THIS
MORNING AND GUST UP TO 20 KNOTS THE BULK OF THE DAY...ESPECIALLY
DURING ANY OF THE HEAVIER RAIN SHOWERS.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HAL/GREIF
SHORT TERM...GREIF
LONG TERM...KAS
AVIATION...GREIF
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
645 AM EST MON DEC 21 2015
.UPDATE...
ISSUED AT 620 AM EST MON DEC 21 2015
A LINE OF MEASURABLE RAIN SHOWERS IS MAKING STEADY PROGRESS
THROUGH CENTRAL KENTUCKY AND WILL BE IN HERE SHORTLY AFTER 12Z.
WILL UPDATED THE POPS TO BETTER TIME THIS FEATURE. ALSO...SOME OF
THE EASTERN VALLEYS ARE STILL IN THE 30S...BUT MOST OF THE AREA IS
SEEING MID AND UPPER 40S OUT THERE FOR TEMPERATURES. WILL ALSO
ADJUST THESE PER THE LATEST SHORTBLEND GUIDANCE...CURRENT OBS...
AND TRENDS. THESE UPDATED GRIDS WILL BE SENT TO THE NDFD AND WEB
SERVERS.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 330 AM EST MON DEC 21 2015
08Z SFC ANALYSIS SHOWS A RELATIVELY TIGHT PRESSURE GRADIENT OVER
KENTUCKY BETWEEN HIGH PRESSURE RETREATING TO THE EAST WHILE DEEP
LOW PRESSURE MOVES INTO THE CENTRAL PLAINS. THIS GRADIENT...IN
ADDITION TO A LAYER OF THICK HIGH CLOUDS...IS SUPPORTING A MILDER
NIGHT ACROSS EAST KENTUCKY WITH READINGS IN MOST PLACES IN THE MID
40S. HOWEVER...SOME OF THE FAR EASTERN VALLEY ARE SHELTERED ENOUGH
THAT THEY HAVE MADE IT TO NEAR FREEZING. EXPECT THESE TO MIX OUT
BEFORE DAWN AND QUICKLY RISE INTO THE MID 40S WHEN THE WINDS PICK
UP FROM THE SOUTH AT 5 TO 10 MPH. MEANWHILE...DEWPOINTS ARE
GENERALLY IN THE MID TO UPPER 20S THROUGHOUT EAST KENTUCKY EARLY
THIS MORNING WITH ANY RETURNS SHOWING UP ON RADAR TOO WEAK TO MAKE
IT TO THE SFC GIVEN THE DRY LOW LAYERS.
THE MODELS ARE IN GOOD AGREEMENT ALOFT THROUGH THE SHORT TERM
PORTION OF THE FORECAST. THEY ALL DEPICT A FLAT SOUTHEAST RIDGE
MOVING OFF TO THE EAST IN THE FACE OF A PAIR OF COMPACT SHORTWAVES
ROLLING PAST TO THE NORTHWEST OF THE JKL CWA. THE FIRST WILL BE
WEAKENING AS IT MOVES INTO THE NORTHERN OHIO VALLEY FROM THE
SOUTHERN PLAINS LATER TODAY...THOUGH SOME WEAK ENERGY IS MOVING
OVERHEAD CURRENTLY...AS WELL. AFTER A BRIEF REBUILD OF THE RIDGE
THE NEXT MID LEVEL WAVE CROSSES INTO THE CENTRAL OHIO VALLEY BY
DAWN TUESDAY...MAINTAINING ITS STRENGTH BETTER. THE RIDGE WILL
THEN HOLD ON TOUGH SOUTHEAST OF KENTUCKY WHILE THE BROAD SOUTHWEST
FLOW CONTINUES THROUGHOUT THE REGION AND ENERGY STARTS TO
RECHARGE TO THE SOUTHWEST. GIVEN THE MODEL AGREEMENT...HAVE AGAIN
FAVORED SOLUTIONS FROM THE HIGHER RESOLUTION HRRR AND NAM12...WITH
RESPECT TO WEATHER DETAILS.
SENSIBLE WEATHER WILL FEATURE A MILD START FOR MOST TODAY...ASIDE
FROM THE DEEP...SHELTERED VALLEYS IN THE EAST. AN
APPROACHING...BUT STALLING...COLD FRONT WILL PROVIDE A GLIDE PATH
FOR WAVES OF MOISTURES TO MOVE OVER EASTERN KENTUCKY DURING THE
SHORT TERM PORTION OF THE FORECAST AND BEYOND. LOOK FOR A WEAK ONE
TO PASS THROUGH LATER TODAY WITH A DECENT CHANCE FOR SHOWERS...
HOWEVER...AFTER A SHORT LULL...ANOTHER STRONGER AND WETTER WAVE
WILL PASS THROUGH TONIGHT INTO TUESDAY MORNING. PERSISTENT SOUTH
TO SOUTHWEST WINDS WILL KEEP TEMPERATURES WARM THROUGH THE MIDDLE
OF WEEK AND BEYOND...AS WELL. HIGHS TODAY WILL BE IN THE MID TO
UPPER 50S FOR MOST PLACES WITH LOW 60S ON TAP FOR TUESDAY. WE ARE
LOOKING FOR GENERALLY JUST A FEW TENTHS OF AN INCH OF RAINFALL
TODAY FOLLOWED BY A QUARTER TO A HALF AN INCH OF ACCUMULATION
TONIGHT WITH ANOTHER TENTH OR SO POSSIBLE DURING THE DAY TUESDAY.
FOR TEMPERATURES AND DEWPOINTS...HAVE AGAIN STARTED WITH THE
SHORTBLEND GRIDS INTO TONIGHT FOLLOWED BY THE SUPERBLEND THROUGH
THE DAY TUESDAY. ONLY MADE MINOR CHANGES TO THE TEMPERATURES GIVEN
THE MOIST...CLOUDY...AND LIKELY WELL MIXED ENVIRONMENT IN PLACE
FOR THE SHORT TERM. AS FOR POPS...ENDED UP MOST SIMILAR TO THE
MET VALUES FOR TODAY INTO TUESDAY...THOUGH THE MAV IS NOT FAR
OFF...EITHER.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 320 AM EST MON DEC 21 2015
RECORD BREAKING WARMTH ALONG WITH SEVERAL PERIODS OF RAIN WILL
CONTINUE TO HIGHLIGHT THE WEATHER FORECAST AS WE HEAD TOWARDS AND
PAST CHRISTMAS.
THE PERIOD WILL START WITH A SHORTWAVE TROUGH MOVING UP THE SPINE OF
THE APPALACHIANS. WITH THE STALLED FRONTAL BOUNDARY TO OUR
NORTHWEST...WE SHOULD SEE MOISTURE INCREASE AS THIS SYSTEM SPREADS
NORTHWARD TUESDAY NIGHT. THIS WILL LEAD TO QUICKLY INCREASING RAIN
CHANCES. THE BULK OF THE RAIN SHOULD COME PRIOR TO DAYBREAK...WITH
THE WAVE DEPARTING QUICKLY TO THE NORTH. THIS WILL SET UP A
POTENTIAL DRY START TO THE DAY. DESPITE THE CLOUDS...TEMPERATURES
WILL LIKELY CLIMB CLOSE TO 70...LIKELY ECLIPSING A FEW RECORDS. RAIN
CHANCES WILL INCREASE AS WE HEAD INTO THE EVENING HOURS AS A
SHORTWAVE TROUGH PUSHES INTO THE GREAT LAKES...HELPING TO PUSH A
COLD FRONT ACROSS THE OHIO RIVER VALLEY. MODELS ARE SHOWING
CONSISTENT SIGNS OF WIDESPREAD RAIN AS THIS FRONT APPROACHES THE
AREA...SO WILL GO WITH CATEGORICAL RAIN CHANCES. IN ADDITION...MID
LEVEL LAPSE RATES WILL STEEPEN UP A BIT AHEAD OF THE FRONT...SO PLAN
TO INCLUDE A SLIGHT THREAT FOR SOME THUNDER THROUGH FROM WEDNESDAY
EVENING THROUGH THE OVERNIGHT HOURS. THE FRONT WILL LIKELY NOT MAKE
IT THROUGH THE AREA AND STALL BEFORE IT REACHES EASTERN
KENTUCKY...WITH RAIN CHANCES LIKELY LINGERING THROUGH MUCH OF
CHRISTMAS EVE...ESPECIALLY IN THE SOUTHEAST. RECORDS COULD
POTENTIALLY BE REACHED ON THURSDAY AS WELL IF THE RAIN EXITS EARLY
ENOUGH ALLOWING TIME FOR OUR TEMPERATURES TO RECOVER.
MODEL UNCERTAINTY GREATLY INCREASES CHRISTMAS MORNING THROUGH THE
FOLLOWING WEEKEND. WHILE CONFIDENCE IS LOW...GENERAL EVOLUTION
WOULD SUPPORT A WARM FRONT LIFTING NORTH ACROSS THE AREA ON
CHRISTMAS OR FRIDAY NIGHT...WITH ANOTHER SURGE OF WIDESPREAD RAIN.
THIS FRONT WILL THEN STALL OR CONTINUE MOVING NORTH THIS WEEKEND
WITH EVEN WARMER TEMPERATURES SPREADING NORTH FOR THE WEEKEND. ONCE
AGAIN...RECORD TEMPERATURES WILL BE POSSIBLE SATURDAY THROUGH MONDAY
AS WE COULD EASILY REACH THE MID TO UPPER 60S EACH DAY AND LIKELY
END UP IN THE LOWER 70S FOR A FEW OF THE DAYS IF CLOUDS DISSIPATE
ENOUGH. DEPENDING HOW FAR NORTH THE FRONT MOVES WILL DETERMINE HOW
MUCH RAIN WE SEE OVER THE WEEKEND. ECMWF LIFTS THE FRONT WELL
NORTH...KEEPING MUCH OF KENTUCKY DRY FROM LATE SATURDAY THROUGH
MONDAY. GFS IS FARTHER SOUTH AND WOULD KEEP SOME RAIN CHANCES OVER
THE AREA. FOR NOW...WILL KEEP SOME RAIN CHANCES IN THE
FORECAST...BUT TREND THE FORECAST WARMER FOR THE WEEKEND. IT LOOKS
LIKE THE WARMTH MAY HOLD THROUGH THE END OF THE YEAR.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 645 AM EST MON DEC 21 2015
AN APPROACHING COLD FRONT WILL BRING IN A DECK OF MID LEVEL CIGS
EARLY IN THE PERIOD. BETWEEN 12 AND 14Z...THOUGH...RAIN SHOWERS
WILL BEGIN MOVING INTO THE WESTERN TAF SITES...SPREADING EASTWARD
AS CLOUDS CONTINUE TO LOWER TO NEAR MVFR CONDITIONS. EXPECT RAIN
CHANCES AND MVFR CIGS TO INCREASE THROUGHOUT THE REST OF THE
AFTERNOON...WITH PREVAILING RAIN EXPECTED BETWEEN 14 AND 19Z.
AFTER A LULL ANOTHER ROUND OF SHOWERS WILL BE POSSIBLE LATER
TONIGHT. WINDS WILL INCREASE FROM THE SOUTH TO SOUTHWEST THIS
MORNING AND GUST UP TO 20 KNOTS THE BULK OF THE DAY...ESPECIALLY
DURING ANY OF THE HEAVIER RAIN SHOWERS.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GREIF
SHORT TERM...GREIF
LONG TERM...KAS
AVIATION...GREIF
AREA FORECAST DISCUSSION
National Weather Service Paducah KY
543 AM CST MON DEC 21 2015
.SHORT TERM...(Today through Wednesday night)
Issued at 305 AM CST MON DEC 21 2015
With a broad ridge in the Central Pacific and a series of
shortwaves expected to dig and rotate around a broad trough in the
southwest U.S. Unfortunately, this places the WFO PAH forecast
area in a broad southwesterly flow aloft, subject to frequent
instrusions of sharper lapse rates from passing upper level jet
dynamics and low level moist/warm advection scenarios.
The last 24 hours has seen a more dramatic (but not totally
unexpected) shift of better instability into the WFO PAH forecast
area. Enhanced convective activity over Western MO at this time is
just better evidence of the increased shear aloft and instability.
For the short term, blended the higher resolution HRRR explicit
model convective suite with the broader ECMWF/Canadian/GFS to
account for precipitation chances within and across several hours.
Added a wing of isolated thunderstorm chances riding up the
southeast MO foothills and into Southwest IL toward the I-64
corridor through the noon hour and the instability works northeast
with the approaching wave and slowing and weakening cold front.
The trend introduced yesterday of a break in the convective
activity late tonight and into Tuesday continues to be supported
as instability and moisture are lacking. However, this is short-
lived as the next shortwave (much more amplified in the 00z Monday Canadian
and GFS deterministic guidance versus the ECMWF) provides enough
ageostrophic response to lower pressures and reform the frontal
boundary, as well as sharpen moisture/theta-e advection back
northward late Tuesday afternoon and evening. The proximity of the
core of the stronger winds and instability should begin to support
sufficient updrafts for upright convection (thunderstorms). These
will advect northeast from Arkansas and Tennessee fairly quickly
by daybreak on Wednesday.
A strong enough gradient of moisture, shear, instability will be
in place Wednesday afternoon and evening to support a short
episode of enhanced convection and minor severe potential. Some of
this will be dependent on the degree of convection in the lower
Mississippi Valley impacting the degree and quality moisture
advection into the area.
Did not due a good job of temporal temperature trends in the light
of warm advection yesterday. Somewhat difficult to adequately
depict non-diurnal temperature trends. Temperatures on Wednesday
reflect some minor breaks in the cloud cover combined with strong
warm air advection. Could have gone a couple of degrees higher,
but timing of convection and cloud debris creates greater
uncertainty for seeing temperatures 25-30 degrees above normal at
this time.
.LONG TERM...(Thursday through Sunday)
Issued at 305 AM CST MON DEC 21 2015
An unsettled pattern is forecast in the long term. The 21/00z GFS
and 20/12z ECMWF were a pretty good match with the h5 pattern.
The new 21/00z ECMWF is also in line. Having said that, there have
been considerable run to run continuity issues prior, especially
with the evolution of a closed low over the SW U.S., and its effects
on the steering flow across our area, and resultant frontal
position, which is important with respect to PoPs. Therefore, the
uncertainty factor involved means keeping PoPs more broad brush
spatially with slightly lower values farther out in time.
For Thursday into Thursday evening (Christmas Eve), will carry a dry
forecast. The ECMWF continues to develop showers into southern
sections of the CWFA before daybreak Christmas. The other models do
not. Have slight chances to cover this early morning chance. PoPs
increase from south to north Friday through Friday night, with a
thunder chance also in play. Saturday into Sunday, the general
depiction is best chance PoPs will shift to NW sections of the CWFA
and lower across the SE (west KY) as the upper steering flow backs.
Will continue to carry thunder through the duration for the most
part as elevated instability and favorable mid level lapse rates
are maintained in both the ECMWF and GFS. Some locally heavy rain
cannot be ruled out, but still too soon as far as the details
including placement and amounts.
There continues to be a moderate spread with respect to temperatures
Friday and beyond, depending on the period. To minimize potential
errors, incorporated persistence with the latest Ensemble MOS
numbers. We incorporated Raw Model output where MOS is least likely
to deviate from its climo aspect as well. Overall, above normal
temperatures will be the rule.
&&
.AVIATION...
Issued at 542 AM CST MON DEC 21 2015
Following the current passage of the bands of convection this
morning and into the afternoon, the WFO PAH TAF sites will
transition from lower MVFR ceilings to periodic IFR ceilings in
advance of the approaching cold front. Frontal passage will move
near or past the kcgi and kevv TAF site in the 05z to 08z Tuesday
time frame with corresponding visibilties between 1 1/2 to 3
statute miles.
&&
.PAH Watches/Warnings/Advisories...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
SHORT TERM...Smith
LONG TERM...CN
AVIATION...Smith
AREA FORECAST DISCUSSION
National Weather Service Paducah KY
306 AM CST MON DEC 21 2015
.SHORT TERM...(Today through Wednesday night)
Issued at 305 AM CST MON DEC 21 2015
With a broad ridge in the Central Pacific and a series of
shortwaves expected to dig and rotate around a broad trough in the
southwest U.S. Unfortunately, this places the WFO PAH forecast
area in a broad southwesterly flow aloft, subject to frequent
instrusions of sharper lapse rates from passing upper level jet
dynamics and low level moist/warm advection scenarios.
The last 24 hours has seen a more dramatic (but not totally
unexpected) shift of better instability into the WFO PAH forecast
area. Enhanced convective activity over Western MO at this time is
just better evidence of the increased shear aloft and instability.
For the short term, blended the higher resolution HRRR explicit
model convective suite with the broader ECMWF/Canadian/GFS to
account for precipitation chances within and across several hours.
Added a wing of isolated thunderstorm chances riding up the
southeast MO foothills and into Southwest IL toward the I-64
corridor through the noon hour and the instability works northeast
with the approaching wave and slowing and weakening cold front.
The trend introduced yesterday of a break in the convective
activity late tonight and into Tuesday continues to be supported
as instability and moisture are lacking. However, this is short-
lived as the next shortwave (much more amplified in the 00z Monday Canadian
and GFS deterministic guidance versus the ECMWF) provides enough
ageostrophic response to lower pressures and reform the frontal
boundary, as well as sharpen moisture/theta-e advection back
northward late Tuesday afternoon and evening. The proximity of the
core of the stronger winds and instability should begin to support
sufficient updrafts for upright convection (thunderstorms). These
will advect northeast from Arkansas and Tennessee fairly quickly
by daybreak on Wednesday.
A strong enough gradient of moisture, shear, instability will be
in place Wednesday afternoon and evening to support a short
episode of enhanced convection and minor severe potential. Some of
this will be dependent on the degree of convection in the lower
Mississippi Valley impacting the degree and quality moisture
advection into the area.
Did not due a good job of temporal temperature trends in the light
of warm advection yesterday. Somewhat difficult to adequately
depict non-diurnal temperature trends. Temperatures on Wednesday
reflect some minor breaks in the cloud cover combined with strong
warm air advection. Could have gone a couple of degrees higher,
but timing of convection and cloud debris creates greater
uncertainty for seeing temperatures 25-30 degrees above normal at
this time.
.LONG TERM...(Thursday through Sunday)
Issued at 305 AM CST MON DEC 21 2015
An unsettled pattern is forecast in the long term. The 21/00z GFS
and 20/12z ECMWF were a pretty good match with the h5 pattern.
The new 21/00z ECMWF is also in line. Having said that, there have
been considerable run to run continuity issues prior, especially
with the evolution of a closed low over the SW U.S., and its effects
on the steering flow across our area, and resultant frontal
position, which is important with respect to PoPs. Therefore, the
uncertainty factor involved means keeping PoPs more broad brush
spatially with slightly lower values farther out in time.
For Thursday into Thursday evening (Christmas Eve), will carry a dry
forecast. The ECMWF continues to develop showers into southern
sections of the CWFA before daybreak Christmas. The other models do
not. Have slight chances to cover this early morning chance. PoPs
increase from south to north Friday through Friday night, with a
thunder chance also in play. Saturday into Sunday, the general
depiction is best chance PoPs will shift to NW sections of the CWFA
and lower across the SE (west KY) as the upper steering flow backs.
Will continue to carry thunder through the duration for the most
part as elevated instability and favorable mid level lapse rates
are maintained in both the ECMWF and GFS. Some locally heavy rain
cannot be ruled out, but still too soon as far as the details
including placement and amounts.
There continues to be a moderate spread with respect to temperatures
Friday and beyond, depending on the period. To minimize potential
errors, incorporated persistence with the latest Ensemble MOS
numbers. We incorporated Raw Model output where MOS is least likely
to deviate from its climo aspect as well. Overall, above normal
temperatures will be the rule.
&&
.AVIATION...
Issued at 516 PM CST SUN DEC 20 2015
Bulk moisture headed in/down the column will result in lowering
cigs and ultimately showers by late tonight-early tmrw for all
terminals. Inherited IFR cigs and will calibrate around that as we
extend the forecast thru the pm hours. Should see diurnal
improvement to MVFR although vicinity showers could still
impact...esp further south and east (KOWB).
&&
.PAH Watches/Warnings/Advisories...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
SHORT TERM...Smith
LONG TERM...CN
AREA FORECAST DISCUSSION
NWS JACKSON KY
330 AM EST MON DEC 21 2015
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 330 AM EST MON DEC 21 2015
08Z SFC ANALYSIS SHOWS A RELATIVELY TIGHT PRESSURE GRADIENT OVER
KENTUCKY BETWEEN HIGH PRESSURE RETREATING TO THE EAST WHILE DEEP
LOW PRESSURE MOVES INTO THE CENTRAL PLAINS. THIS GRADIENT...IN
ADDITION TO A LAYER OF THICK HIGH CLOUDS...IS SUPPORTING A MILDER
NIGHT ACROSS EAST KENTUCKY WITH READINGS IN MOST PLACES IN THE MID
40S. HOWEVER...SOME OF THE FAR EASTERN VALLEY ARE SHELTERED ENOUGH
THAT THEY HAVE MADE IT TO NEAR FREEZING. EXPECT THESE TO MIX OUT
BEFORE DAWN AND QUICKLY RISE INTO THE MID 40S WHEN THE WINDS PICK
UP FROM THE SOUTH AT 5 TO 10 MPH. MEANWHILE...DEWPOINTS ARE
GENERALLY IN THE MID TO UPPER 20S THROUGHOUT EAST KENTUCKY EARLY
THIS MORNING WITH ANY RETURNS SHOWING UP ON RADAR TOO WEAK TO MAKE
IT TO THE SFC GIVEN THE DRY LOW LAYERS.
THE MODELS ARE IN GOOD AGREEMENT ALOFT THROUGH THE SHORT TERM
PORTION OF THE FORECAST. THEY ALL DEPICT A FLAT SOUTHEAST RIDGE
MOVING OFF TO THE EAST IN THE FACE OF A PAIR OF COMPACT SHORTWAVES
ROLLING PAST TO THE NORTHWEST OF THE JKL CWA. THE FIRST WILL BE
WEAKENING AS IT MOVES INTO THE NORTHERN OHIO VALLEY FROM THE
SOUTHERN PLAINS LATER TODAY...THOUGH SOME WEAK ENERGY IS MOVING
OVERHEAD CURRENTLY...AS WELL. AFTER A BRIEF REBUILD OF THE RIDGE
THE NEXT MID LEVEL WAVE CROSSES INTO THE CENTRAL OHIO VALLEY BY
DAWN TUESDAY...MAINTAINING ITS STRENGTH BETTER. THE RIDGE WILL
THEN HOLD ON TOUGH SOUTHEAST OF KENTUCKY WHILE THE BROAD SOUTHWEST
FLOW CONTINUES THROUGHOUT THE REGION AND ENERGY STARTS TO
RECHARGE TO THE SOUTHWEST. GIVEN THE MODEL AGREEMENT...HAVE AGAIN
FAVORED SOLUTIONS FROM THE HIGHER RESOLUTION HRRR AND NAM12...WITH
RESPECT TO WEATHER DETAILS.
SENSIBLE WEATHER WILL FEATURE A MILD START FOR MOST TODAY...ASIDE
FROM THE DEEP...SHELTERED VALLEYS IN THE EAST. AN
APPROACHING...BUT STALLING...COLD FRONT WILL PROVIDE A GLIDE PATH
FOR WAVES OF MOISTURES TO MOVE OVER EASTERN KENTUCKY DURING THE
SHORT TERM PORTION OF THE FORECAST AND BEYOND. LOOK FOR A WEAK ONE
TO PASS THROUGH LATER TODAY WITH A DECENT CHANCE FOR SHOWERS...
HOWEVER...AFTER A SHORT LULL...ANOTHER STRONGER AND WETTER WAVE
WILL PASS THROUGH TONIGHT INTO TUESDAY MORNING. PERSISTENT SOUTH
TO SOUTHWEST WINDS WILL KEEP TEMPERATURES WARM THROUGH THE MIDDLE
OF WEEK AND BEYOND...AS WELL. HIGHS TODAY WILL BE IN THE MID TO
UPPER 50S FOR MOST PLACES WITH LOW 60S ON TAP FOR TUESDAY. WE ARE
LOOKING FOR GENERALLY JUST A FEW TENTHS OF AN INCH OF RAINFALL
TODAY FOLLOWED BY A QUARTER TO A HALF AN INCH OF ACCUMULATION
TONIGHT WITH ANOTHER TENTH OR SO POSSIBLE DURING THE DAY TUESDAY.
FOR TEMPERATURES AND DEWPOINTS...HAVE AGAIN STARTED WITH THE
SHORTBLEND GRIDS INTO TONIGHT FOLLOWED BY THE SUPERBLEND THROUGH
THE DAY TUESDAY. ONLY MADE MINOR CHANGES TO THE TEMPERATURES GIVEN
THE MOIST...CLOUDY...AND LIKELY WELL MIXED ENVIRONMENT IN PLACE
FOR THE SHORT TERM. AS FOR POPS...ENDED UP MOST SIMILAR TO THE
MET VALUES FOR TODAY INTO TUESDAY...THOUGH THE MAV IS NOT FAR
OFF...EITHER.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 320 AM EST MON DEC 21 2015
RECORD BREAKING WARMTH ALONG WITH SEVERAL PERIODS OF RAIN WILL
CONTINUE TO HIGHLIGHT THE WEATHER FORECAST AS WE HEAD TOWARDS AND
PAST CHRISTMAS.
THE PERIOD WILL START WITH A SHORTWAVE TROUGH MOVING UP THE SPINE OF
THE APPALACHIANS. WITH THE STALLED FRONTAL BOUNDARY TO OUR
NORTHWEST...WE SHOULD SEE MOISTURE INCREASE AS THIS SYSTEM SPREADS
NORTHWARD TUESDAY NIGHT. THIS WILL LEAD TO QUICKLY INCREASING RAIN
CHANCES. THE BULK OF THE RAIN SHOULD COME PRIOR TO DAYBREAK...WITH
THE WAVE DEPARTING QUICKLY TO THE NORTH. THIS WILL SET UP A
POTENTIAL DRY START TO THE DAY. DESPITE THE CLOUDS...TEMPERATURES
WILL LIKELY CLIMB CLOSE TO 70...LIKELY ECLIPSING A FEW RECORDS. RAIN
CHANCES WILL INCREASE AS WE HEAD INTO THE EVENING HOURS AS A
SHORTWAVE TROUGH PUSHES INTO THE GREAT LAKES...HELPING TO PUSH A
COLD FRONT ACROSS THE OHIO RIVER VALLEY. MODELS ARE SHOWING
CONSISTENT SIGNS OF WIDESPREAD RAIN AS THIS FRONT APPROACHES THE
AREA...SO WILL GO WITH CATEGORICAL RAIN CHANCES. IN ADDITION...MID
LEVEL LAPSE RATES WILL STEEPEN UP A BIT AHEAD OF THE FRONT...SO PLAN
TO INCLUDE A SLIGHT THREAT FOR SOME THUNDER THROUGH FROM WEDNESDAY
EVENING THROUGH THE OVERNIGHT HOURS. THE FRONT WILL LIKELY NOT MAKE
IT THROUGH THE AREA AND STALL BEFORE IT REACHES EASTERN
KENTUCKY...WITH RAIN CHANCES LIKELY LINGERING THROUGH MUCH OF
CHRISTMAS EVE...ESPECIALLY IN THE SOUTHEAST. RECORDS COULD
POTENTIALLY BE REACHED ON THURSDAY AS WELL IF THE RAIN EXITS EARLY
ENOUGH ALLOWING TIME FOR OUR TEMPERATURES TO RECOVER.
MODEL UNCERTAINTY GREATLY INCREASES CHRISTMAS MORNING THROUGH THE
FOLLOWING WEEKEND. WHILE CONFIDENCE IS LOW...GENERAL EVOLUTION
WOULD SUPPORT A WARM FRONT LIFTING NORTH ACROSS THE AREA ON
CHRISTMAS OR FRIDAY NIGHT...WITH ANOTHER SURGE OF WIDESPREAD RAIN.
THIS FRONT WILL THEN STALL OR CONTINUE MOVING NORTH THIS WEEKEND
WITH EVEN WARMER TEMPERATURES SPREADING NORTH FOR THE WEEKEND. ONCE
AGAIN...RECORD TEMPERATURES WILL BE POSSIBLE SATURDAY THROUGH MONDAY
AS WE COULD EASILY REACH THE MID TO UPPER 60S EACH DAY AND LIKELY
END UP IN THE LOWER 70S FOR A FEW OF THE DAYS IF CLOUDS DISSIPATE
ENOUGH. DEPENDING HOW FAR NORTH THE FRONT MOVES WILL DETERMINE HOW
MUCH RAIN WE SEE OVER THE WEEKEND. ECMWF LIFTS THE FRONT WELL
NORTH...KEEPING MUCH OF KENTUCKY DRY FROM LATE SATURDAY THROUGH
MONDAY. GFS IS FARTHER SOUTH AND WOULD KEEP SOME RAIN CHANCES OVER
THE AREA. FOR NOW...WILL KEEP SOME RAIN CHANCES IN THE
FORECAST...BUT TREND THE FORECAST WARMER FOR THE WEEKEND. IT LOOKS
LIKE THE WARMTH MAY HOLD THROUGH THE END OF THE YEAR.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 130 AM EST MON DEC 21 2015
HIGH PRESSURE WILL REMAIN IN CONTROL ACROSS THE REGION THROUGH
THE FIRST PART OF THE TAF PERIOD...PROVIDING VFR CONDITIONS UNDER
THICKENING HIGH CLOUDS. AN APPROACHING COLD FRONT WILL BRING IN A
DECK OF MID LEVEL CIGS TOWARD DAWN. BY 14Z...THOUGH...RAIN
SHOWERS WILL BEGIN MOVING INTO THE WESTERN TAF SITES...SPREADING
EASTWARD AS CLOUDS CONTINUE TO LOWER TO NEAR MVFR CONDITIONS.
EXPECT RAIN CHANCES AND MVFR CIGS TO INCREASE THROUGHOUT THE REST
OF THE AFTERNOON...WITH PREVAILING RAIN EXPECTED BETWEEN 16 AND
21Z. WINDS WILL BE LIGHT AND VARIABLE THROUGH MID MORNING...
BEFORE INCREASING AND GUSTING UP TO 20 KNOTS OUT OF THE SOUTH
FOR THE AFTERNOON...ESPECIALLY DURING ANY OF THE HEAVIER RAIN
SHOWERS.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GREIF
LONG TERM...KAS
AVIATION...GREIF/JMW
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
934 PM EST TUE DEC 22 2015
.SYNOPSIS...
A STEADY FEED OF MOISTURE ON THE BACK SIDE OF HIGH PRESSURE OVER
THE WESTERN ATLANTIC WILL KEEP THE UNSEASONABLY WARM AND UNSETTLED
CONDITIONS ACROSS THE AREA THROUGH THURSDAY. A WEAK COLD FRONT
APPROACHES LATE THURSDAY...THEN STALLS ACROSS THE AREA THROUGH
THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
VRB LYRD CLDNS OVR THE FA THIS EVE. (SCT) -RA CONTG TO MOVE NE
ACRS MOSTLY NE NC ATTM. WIDESPREAD ST (CIGS 500-1500FT) MNLY ACRS
FM I 95 ON W...ALG W/ PATCHY FG. 00Z/23 RUC HAS AREA OF RA
BLOSSOMING FM SCNTRL VA S THROUGH WRN PORTION OF NC AFT
MDNGT...WHICH CONTS TO SPREAD TO THE N AND NE THROUGH THE REST OF
THE NGT. MEANWHILE...RA WILL RMN LIKELY INVOF THE CST. WILL NEED
TO MONITOR FG...ESP INLAND...THOUGH RIGHT NOW XPCG MOSTLY LO ST
OVR WIDESPREAD FG. LO TEMPS IN THE U50S TO ARND 60F.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
SAID S/W PROGGED TO TRACK NE ALONG THE SPINE OF THE MTS WED. THIS
SYSTM TAPS COPIOUS AMTS OF GOM MSTR AND DRIVES IT NE. MSTR OFF THE
ATLNTC GETS ENTRAINED INTO THE SYSTM AS WELL. APPEARS THE BULLSEYE
FOR THE HEAVIEST RAINFALL WILL BE ACROSS THE MTS. FOR AKQ FA...THIS
WUD MOST AFFECT THE VA PIEDMONT MAINLY WEST OF I95 WHERE BTWN 1 TO
1.5 INCHES WILL BE PSBL (HIGHEST OUT NR LKU-FVX). RAINFALL TDY WAS
ARND AN INCH. AFTR THE COORD CALL AND GIVEN THE QUICK MOVMNT OF THE
HEAVIEST AXIS OF RAINFALL WED...NO FLOOD PRODUCTS WILL BE ISSUED
WITH THIS PACKAGE. THE RUNOFF WILL LIKELY END UP IN THE RIVERS
RAISING LEVELS OVER THE NEXT FEW DAYS.
AS THE BEST OMEGA LIFTS NORTH WED AFTRN...PCPN BECOMES SOMEWHAT MORE
CONVECTIVE THAN STRATIFORM GIVEN THE UNUSUAL WARM AIRMASS. NOT
MUCH INSTABILITY PROGGED...BUT CAN NOT RULE OUT ELVATED THUNDER
DRNG THE AFTR AS WAVES OF PCPN TRAVERSE EAST DUE TO LINGERING
TROFINESS. DESPITE THE CLOUDS/PCPN...TMPS APPRCH RECORD LEVELS IN
SOME AREAS. HIGHS 70-75.
MAIN LOW LIFTS NORTH INTO SRN NEW ENGLAND WED NITE. COPIOUS AMTS OF
MSTR REMAIN ACROSS THE FA DUE TO WEAK DISTURBANCES MOVG NE. TSCTNS
LOADED WITH ENUF MSTR TO KEEP CHC/LIKELY POPS GOING. FOG WILL BECOME
AN ISSUE ONCE AGAIN. WARM AND RTHR HUMID WITH LOWS IN THE M-U60S.
MODELS SHOWING AKQ FA IN A WARM SECTOR SCENARIO FOR X-MAS EVE AHEAD
OF THE APPRCHG BNDRY TO THE NW. NOT MUCH SPRT FOR PCPN UNTIL THE
AFTRN WHERE SCT CONVECTION IS PSBL GIVEN THE AVAILABLE MSTR AND
ADVANCING BNDRY. HIGHS WILL ALL DEPEND ON HOW MUCH SUN DVLPS...BUT
ALL DATA SHOWING SUMMER LIKE READINGS WITH HIGHS 75-80. IT IS NOT A
QUESTION ON WHETHER WE SET NEW RECORD HIGH TMPS...BUT BY HOW MUCH???
WILL FEEL MORE LIKE LABOR DAY THAN X-MAS EVE.
CHC POPS THU NITE ALONG WITH MORE FOG PTNTL AS THE BNDRY WEAKENS BUT
LINGERS ACROSS THE AREA. WARM AND HUMID ONCE AGAIN WITH LOWS U50S
NORTH TO M60S SOUTH.
MODELS DIFFER FRI ON JUST WHERE THE BNDRY ENDS UP. CONSENSUS IS FOR
IT TO SAG SOUTH AS A BKDR COLD FRNT TO NE THE VA/NC BORDER. ENUF
MSTR TO KEEP CHC POPS IN FCST. NOT AS WARM...BUT STILL WELL ABV
NRML. WINDS TURN NORTH FOR A SHORT TIME ALLOWING SOMEWHAT COOLER
AIR TO FILTER SOUTH. HIGHS RANGE FROM THE M-U60S OVER THE ERN
SHORE...L- M70S ELSEWHERE. THESE VALUES FALLING JUST SHY OF THE
RECORD HIGHS FOR X-MAS DAY.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
THE LONG TERM PERIOD WILL FEATURE A CONTINUATION OF WARM TEMPS AND
CHANCES FOR SHOWERS. RIDGING OVER THE SOUTHEASTERN STATES WILL
PREVENT SIGNIFICANT AIR MASS CHANGES. A WEAK FRONTAL BOUNDARY WILL
BE OVER THE MID ATLANTIC STATES DURING THE LONG TERM PERIOD. THERE
IS GENERALLY A 30 PERCENT CHANCE FOR PCPN ALTHOUGH THESE SHOWERS
CHANCES DROP OFF SATURDAY NIGHT AND SUNDAY AND THEN INCREASE ONCE
AGAIN SUNDAY NIGHT THROUGH TUESDAY. PCPN IS NOT EXPECTED TO BE
WIDESPREAD.
HIGH TEMPERATURES WILL GENERALLY RUN IN THE 60S TO LWR 70S EXCEPT
EXCEPT UPR 50S TO 60S ON MONDAY. LOWS ARE FORECAST TO RANGE IN THE
UPR 40S TO 50S NORTH PORTIONS AND 50S TO NEAR 60 PORTIONS.
&&
.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
CONDS DETERIORATE THIS EVENG/OVRNGT AS CIGS DROP TO IFR/LIFR AS
WELL AS AREAS OF FOG PSBL WITH A WARM/MOIST AIRMASS IN PLACE.
CHANCES OF RAIN INCREASE THRU THE LATE OVRNGT HRS AS WELL.
PERIODS OF SHOWERS WITH PSBL IFR WILL CONTINUE WED...WITH
DECREASING CHANCES THURSDAY. EXPECT WIND GUST UP TO 20KT ACROSS
THE AREA DUE TO THE STRENGTHENING PRESSURE GRADIENT AHEAD OF THE
DEVELOPING LOW.
OUTLOOK...A WEAK FRONTAL BOUNDARY WILL BE IN THE VICINITY OF THE
MID ATLANTIC STATES BEGINNING FRIDAY. ASIDE FROM PCPN...PATCHY IFR
CONDITIONS WILL BE PSBL IN THE OUTLOOK PERIOD DURING THE PREDAWN
THROUGH MID MORNING HOURS THU/FRI DUE TO LOW STRATUS AND FOG (BUT
SHOULD NOT BE AS WIDESPREAD AS WED MORNING).
&&
.MARINE...
SOUTH TO SOUTHWEST WINDS WILL PREVAIL OVER THE MARINE AREA
THROUGH EARLY FRIDAY. SEAS IN THE NORTHERN COASTAL WATERS HAVE
FALLEN BELOW 5 FT.
THE PRESSURE GRADIENT TIGHTENS LATE WEDNESDAY AS MESO SCALE LOW
PRESSURE DEVELOPS OVER WEST VIRGINIA AS DEPICTED BY THE NAM.
SOUTHERLY WINDS ARE FORECAST TO INCREASE AND PRODUCE SCA OVER THE
BAY...LOWER JAMES AND CURRITUCK SOUND STARTING AT 18Z. SCA ALSO
STARTS IN THE COASTAL WATERS AT 21Z AS SEAS ARE EXPECTED TO BUILD TO
5 TO 6 FT. CURRENT ADVISORY S OF PARRAMORE ISLAND WILL NEED TO BE
EXTENDED NORTH WHEN THE CURRENT ADVISORY EXPIRES.
WHILE THE WINDS OVER INLAND WATERS DIMINISH ALLOWING THE SCA TO END
AROUND 06Z THURSDAY...THE SCA IN THE COASTAL WATERS WILL CONTINUE AS
SEAS STAY 5 FT OR HIGHER THROUGH MUCH OF THURSDAY.
WINDS DIMINISH FRIDAY AS A WEAK FRONTAL BOUNDARY DROPS INTO THE
REGION. PRESSURE GRADIENT WILL BE WEAK ALONG THE BOUNDARY. CURRENT
INDICATIONS HAVE SEAS BUILDING EARLY NEXT WEEK DUE TO A PROLONGED
PERIOD OF ONSHORE WINDS.
&&
.CLIMATE...
CORRECTED
RECORD HIGH TEMPS FOR DEC 23RD:
RIC...73 IN 1990
ORF...77 IN 1990
SBY...71 IN 1990
ECG...76 IN 2013
RECORD HIGH TEMPS FOR DEC 24TH: RECORD HIGH MIN TEMPS FOR DEC 24TH:
RIC...71 IN 1988 RIC...49 IN 1979
ORF...75 IN 1891 ORF...59 IN 1891
SBY...70 IN 2014 SBY...50 IN 2014
ECG...75 IN 1990 ECG...58 IN 1956
RECORD HIGH TEMPS FOR DEC 25TH: RECORD HIGH MIN TEMPS FOR DEC 25TH:
RIC...74 IN 1955 RIC...58 IN 1964
ORF...75 IN 1964 ORF...59 IN 1964
SBY...73 IN 1932 SBY...60 IN 1964
ECG...75 IN 1955 ECG...56 IN 1964
ALL TIME HIGH TEMPS FOR DEC:
RIC...81 IN 1998
ORF...81 IN 2013
SBY...77 IN 2013
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 1 PM WEDNESDAY TO 1 AM EST THURSDAY
FOR ANZ630>634-638.
SMALL CRAFT ADVISORY FROM 4 PM WEDNESDAY TO 4 PM EST THURSDAY
FOR ANZ650-652-654-656-658.
&&
$$
SYNOPSIS...ALB/MPR
NEAR TERM...ALB
SHORT TERM...MPR
LONG TERM...LSA
AVIATION...MAS/DAP
MARINE...LSA
CLIMATE...AKQ
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1151 AM EST MON DEC 21 2015
.AVIATION...
SHRAS WILL REMAIN WIDESPREAD EARLY TO MID AFTERNOON BEFORE GRADUALLY
BECOMING MORE SCATTERED IN NATURE AS VORTICITY CENTER SHIFT OVER AND
EVENTUALLY EAST OF THE REGION OVERNIGHT. SCT SHRA CHANCES WILL STILL
PERSIST TONIGHT AS A WEAKER SHORTWAVE TRACKS OVER AREA IN THE WAKE
OF THIS MAIN LEAD WAVE. IFR CEILINGS WILL ALSO PERSIST AS THIS DUAL
WAVE STRUCTURE LEADS TO AN ELONGATED LOW PRESSURE SYSTEM/TROUGH THAT
SLOWLY SHIFTS EAST THROUGH THE AREA. IN FACT...THE DIFFUSE PRESSURE
GRADIENT ALONG THE AXIS OF THIS TROUGH MAY VERY WELL LEAD TO LIFR
CONDITIONS LATER TONIGHT...MAINLY FNT/MBS AS THE TRACK OF THE LOW
MAINTAINS SSW FLOW PTK SOUTH THROUGHOUT THE NIGHT. EXPECT IMPROVED
CONDITIONS BY THE END OF THE FORECAST PERIOD AS A SHORTWAVE RIDGE
ACTS TO FORCE THIS BOUNDARY NORTH OF ALL TERMINALS TUESDAY AFTN.
FOR DTW...IFR CONDITIONS WILL PREVAIL FOR THE REST OF TODAY ON INTO
TUESDAY AS LOW PRESSURE SLOWLY TRACKS THROUGH LOWER MICHIGAN. WITH
TIME THIS AFTERNOON...WIDESPREAD SHRAS WILL SHIFT NORTH OF THE
TERMINAL AS MID LEVEL DRY SLOT BRINGS A TRANSITION TO PATCHY -DZ/BR
WITH SCT SHRAS AT TIMES.
//DTW THRESHOLD PROBABILITIES...
* HIGH CONFIDENCE IN CEILINGS BELOW 5000 FEET THROUGH TUESDAY
MORNING.
* HIGH CONFIDENCE IN RAIN AS PRECIPITATION TYPE.
* LOW CONFIDENCE FOR POTENTIAL IN CIGS/VSBY BELOW 200FT AND/OR 1/2SM
LATE TONIGHT.
&&
.PREV DISCUSSION...ISSUED 315 AM EST MON DEC 21 2015
DISCUSSION...
COPIOUS AMOUNT OF UPPER LEVEL ENERGY DIVING SOUTHEAST THROUGH THE
PACIFIC NORTHWEST OVER THE NEXT SEVERAL DAYS...MAINTAINING A WET AND
ACTIVE PATTERN...WITH RECORD WARMTH LIKELY OVER SOUTHEAST MICHIGAN ON
WEDNESDAY.
PACIFIC PINEAPPLE CONNECTION ESTABLISHED THIS MORNING JUST EAST
OF MISSISSIPPI RIVER VALLEY...AND RAIN SHIELD SHOULD CONTINUE TO
BLOSSOM AS UPPER LEVEL WAVE/PV CENTER NEAR KANSAS CITY EARLY THIS
MORNING TRACKS THROUGH FAR SOUTHERN LOWER MICHIGAN THIS AFTERNOON.
WITH FAVORABLE MOISTURE AND FORCING...EXPECTING RAINFALL TOTALS
CLOSING IN ON HALF AN INCH...ESPECIALLY IF WE CAN GET ANY CONVECTIVE
ELEMENTS GOING...AS SHOWALTER INDEX DROPS DOWN TO AROUND 1 C. DID
NOTE SOME LIGHTNING STRIKES OVER EASTERN WISCONSIN YESTERDAY
EVENING...AS WELL AS ONGOING STRIKES UNDERNEATH THE CENTER...BUT
LEFT MENTION OUT OF THE FORECAST IN LINE WITH SPC DAY 1.
VERY STRONG LOW LEVEL WINDS FIELDS AROUND THIS MORNING...PARTIALLY
ARTIFACT OF SURFACE/NEAR SURFACE STABLE LAYER...AND EXPECTING LIMITED
MIXING TODAY...IN LINE WITH RAP SOUNDINGS TO KEEP WIND GUSTS IN THE
25 TO 30 KNOT RANGE...MAINLY SOUTH TOWARD OHIO BORDER...AS SURFACE
TEMPERATURES DON`T BUDGE MUCH FROM PRESENT LOW/MID 40 VALUES.
ALTHOUGH MID LEVEL DRY SLOT LOOKS TO BE MOVING THROUGH THE CWA THIS
EVENING...IT APPEARS THERE WILL BE SUFFICIENT LOW LEVEL
MOISTURE/CONVERGENCE/CYCLONIC FLOW TO MAINTAIN SOME LIGHT
RAINFALL OR DRIZZLE AT THE VERY LEAST. COLD ADVECTION AND WESTERLY
WINDS DEVELOPING LATE TONIGHT WILL ATTEMPT TO DRY THE LOW LEVELS
OUT...BUT WITH STRENGTHENING/LOWERING INVERSION ON TUESDAY...WOULD
EXPECT SUFFICIENT MOISTURE TRAPPED UNDERNEATH TO MAINTAIN CLOUDY
SKIES INTO THE AFTERNOON HOURS...WITH POSSIBLE CLEARING WORKING UP
FROM THE SOUTH LATE.
AMPLIFYING LONGWAVE TROUGH AXIS OVER CENTRAL NORTH AMERICA ON
WEDNESDAY...RESULTING IN VERY STRONG/DEEP SOUTHWEST FLOW
PUMPING WARM AND MOIST AIRMASS INTO LOWER MICHIGAN DURING THE DAY.
LOW LEVEL JET PROGGED TO EXCEED 60 KNOTS. 925 MB TEMPS FORECASTED TO
RISE INTO THE LOWER TEENS...SUGGESTING HIGH TEMPERATURES POTENTIALLY
RISING INTO THE 60S. HOWEVER...SATURATION LOOKS TO BE OCCURRING WITH
THE ISENTROPIC ASCENT/MOISTURE TRANSPORT...AS 850 MB DEW PTS RISE TO
RECORD SETTING 10 C PER 00Z EURO...AND SEEMS LIKELY RAIN WILL
DEVELOP...LIMITING THE MAXES A BIT. EVEN A CONSERVATIVE MAX
FORECAST IN THE 55 TO 60 DEGREE RANGE WILL SET US UP TO BREAK THE
DAILY RECORDS FOR DECEMBER 23RD:
DTW 56 (1893)
FNT 55 (1982)
MBS 53 (1982)
MORE COMPELLING EVIDENCE WITH LI`S DROPPING BELOW ZERO TO INCLUDE A
THUNDER MENTION INTO WEDNESDAY EVENING AS STRENGTHENING/AGGRESSIVE
6 HR 500 MB HEIGHT FALLS (-70 TO -90 M) CENTER WORKS THROUGH THE
CENTRAL GREAT LAKES.
WITH MAIN UPPER WAVE RACING NORTHEAST INTO QUEBEC THURSDAY
MORNING...AND VEERING WINDS FAILING TO BECOME FULLY WEST-
NORTHWEST...AMOUNT OF COLD ADVECTION SPILLING INTO SOUTHERN LOWER
MICHIGAN LATE WEDNESDAY NIGHT INTO THURSDAY IS IN QUESTION. VERY
TIGHT BAROCLINIC ZONE AT 925/850 MB WILL MAKE FOR SENSITIVE
TEMPERATURE FORECAST...BUT ASSUMING 925 MB TEMPS REMAIN A COUPLE
DEGREES ABOVE ZERO...TEMPERATURES SHOULD HAVE NO PROBLEM
HOLDING IN THE UPPER 40S TO LOWER 50S.
MARINE...
AN ELONGATED AREA OF SURFACE LOW PRESSURE WILL LIFT NORTHEASTWARD
THROUGH THE WESTERN AND CENRAL GREAT LAKES TODAY. A MODEST
SOUTHWESTERLY FLOW OF 15 TO 25 KNOTS WILL REMAIN IN PLACE FROM THE
CENTRAL LAKE HURON BASIN SOUTHWARD THROUGH MUCH OF THIS AFTERNOON.
THE STRONGEST WINDS...POTENTIALLY REACHING 30 KNOTS FOR A TIME...ARE
EXPECTED TO BE IN PLACE FROM LAKE ST CLAIR SOUTHWARD INCLUDING THE
MICHIGAN WATERS OF LAKE ERIE. SMALL CRAFT ADVISORIES REMAIN IN
EFFECT FOR THE SOUTHERN MARINE AREAS TO ACCOUNT FOR THE MODERATE
PRESSURE GRADIENT. SURFACE WINDS WILL THEN VEER TO THE WEST IN THE
WAKE OF THE SURFACE LOW PRESSURE TONIGHT AS A WEAK SURFACE RIDGE
PASSES THROUGH THE REGION. A RETURN TO INCREASING MODERATE SOUTHERLY
FLOW IS EXPECTED ON WEDNESDAY AS THE NEXT LOW PRESSURE SYSTEM
ORGANIZES OVER THE NATIONS HEARTLAND.
HYDROLOGY...
AN AREA OF UPPER LEVEL LOW PRESSURE WILL DRAW MOISTURE NORTHWARD
INTO SOUTHEASTERN MICHIGAN THIS MORNING. WIDESPREAD LIGHT TO
MODERATE RAIN WILL DEVELOP BEFORE DAYBREAK AND PERSIST THROUGHOUT
MUCH OF THE DAY. HIGH CONFIDENCE EXISTS FOR RAINFALL AMOUNTS OF
BETWEEN .25 AND .50 OF AN INCH. INDICATIONS ARE THE HIGHER END OF
THE RANGE WILL OCCUR NORTH OF THE I 69 CORRIDOR.
A STRONG WARM FRONT WILL LIFT INTO THE GREAT LAKES REGION ON
WEDNESDAY AHEAD OF THE NEXT DYNAMIC UPPER LEVEL TROUGH. A RETURN OF
RECORD BREAKING WARM TEMPERATURES AND MOISTURE WILL LEAD TO ANOTHER
WIDESPREAD PRECIPITATION EVENT. LATEST FORECAST INFORMATION SUGGESTS
AS MUCH AS .50 TO .75 OF INCH OF RAINFALL WILL BE POSSIBLE WEDNESDAY
AFTERNOON THROUGH THURSDAY NIGHT.
WITH THE TIME SEPARATION BETWEEN EVENTS AND DRY ANTECEDENT
CONDITIONS...LITTLE CONCERN FOR FLOODING POTENTIAL EXISTS.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR LCZ460.
MICHIGAN WATERS OF LAKE ERIE...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR LEZ444.
&&
$$
AVIATION.....DG
DISCUSSION...SF
MARINE.......CB
HYDROLOGY....CB
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
647 AM EST MON DEC 21 2015
.AVIATION...
THE LATEST OBSERVATIONS UPSTREAM SUPPORT THE RECENT MODELED
SOLUTIONS FOR WIDESPREAD IFR CEILINGS TO FILL IN ACROSS SOUTHEASTERN
MICHIGAN AFTER 12Z. PRECIPITATION ASSOCIATED WITH THE MAIN FRONTAL
WAVE IS EXPECTED TO FALL BETWEEN 12-20Z FROM SOUTH TO NORTH.
MIDLEVEL MOISTURE WILL THEN STRIP OUT OF THE COLUMN DURING THE
EVENING...LEAVING BEHIND A STOUT LAYER OF LOW LEVEL
MOISTURE/SATURATION UP TO 6000 FT AGL. PERSISTENCE OF SURFACE
TROUGHING ADDS SUPPORT FOR LINGERING DRIZZLE ACTIVITY THROUGHOUT
MUCH OF THE OVERIGHT. BASED ON THE GUIDANCE THERE IS NOW REASONABLY
HIGHER CONFIDENCE FOR LIFR CONDITIONS DEVELOPING OVERNIGHT. MSLP
CONFIGURATION LENDS SUPPORT FOR FOG NORTH OF AND POSSIBLY ALONG THE
GLACIAL TERRAIN...WITH SLIGHTLY BETTER SURFACE WINDS KEEPING BULK OF
SATURATION LOCKED IN AS AN LIFR CEILING THROUGH 12Z.
FOR DTW...IFR CIGS ON PACE TO BLANKET THE TERMINAL AFTER 13Z.
SURFACE WINDS ARE EXPECTED TO INCREASE THIS MORNING AS THE PRESSURE
GRADIENT TIGHTENS OVER PORTIONS OF OHIO...INTO FAR SOUTHEASTERN
MICHIGAN. THERE IS A MODERATE TO HIGH CHANCE FOR SW WIND GUSTS TO
REACH 26 KNOTS. WIDESPREAD RAIN TO MOVE OUT AROUND 19-20Z THIS
AFTERNOON. LINGERING LOW LEVEL MOISTURE THEN BRINGS INCREASING
CONCERN FOR LIFR CEILINGS TO DEVELOP AFTER 00Z TONIGHT. BETTER
SUPPORT FOR LIFR VISIBILITIES APPEARS TO REMAIN NW OF KDTW.
//DTW THRESHOLD PROBABILITIES...
* HIGH CONFIDENCE IN CEILINGS AOB 5000 FEET TODAY.
* HIGH CONFIDENCE IN RAIN AS PRECIPITATION TYPE.
* LOW CONFIDENCE OR POTENTIAL IN CIGS/VSBY BELOW 200FT AND/OR 1/2SM.
&&
.PREV DISCUSSION...ISSUED 315 AM EST MON DEC 21 2015
DISCUSSION...
COPIOUS AMOUNT OF UPPER LEVEL ENERGY DIVING SOUTHEAST THROUGH THE
PACIFIC NORTHWEST OVER THE NEXT SEVERAL DAYS...MAINTAINING A WET AND
ACTIVE PATTERN...WITH RECORD WARMTH LIKELY OVER SOUTHEAST MICHIGAN ON
WEDNESDAY.
PACIFIC PINEAPPLE CONNECTION ESTABLISHED THIS MORNING JUST EAST
OF MISSISSIPPI RIVER VALLEY...AND RAIN SHIELD SHOULD CONTINUE TO
BLOSSOM AS UPPER LEVEL WAVE/PV CENTER NEAR KANSAS CITY EARLY THIS
MORNING TRACKS THROUGH FAR SOUTHERN LOWER MICHIGAN THIS AFTERNOON.
WITH FAVORABLE MOISTURE AND FORCING...EXPECTING RAINFALL TOTALS
CLOSING IN ON HALF AN INCH...ESPECIALLY IF WE CAN GET ANY CONVECTIVE
ELEMENTS GOING...AS SHOWALTER INDEX DROPS DOWN TO AROUND 1 C. DID
NOTE SOME LIGHTNING STRIKES OVER EASTERN WISCONSIN YESTERDAY
EVENING...AS WELL AS ONGOING STRIKES UNDERNEATH THE CENTER...BUT
LEFT MENTION OUT OF THE FORECAST IN LINE WITH SPC DAY 1.
VERY STRONG LOW LEVEL WINDS FIELDS AROUND THIS MORNING...PARTIALLY
ARTIFACT OF SURFACE/NEAR SURFACE STABLE LAYER...AND EXPECTING LIMITED
MIXING TODAY...IN LINE WITH RAP SOUNDINGS TO KEEP WIND GUSTS IN THE
25 TO 30 KNOT RANGE...MAINLY SOUTH TOWARD OHIO BORDER...AS SURFACE
TEMPERATURES DON`T BUDGE MUCH FROM PRESENT LOW/MID 40 VALUES.
ALTHOUGH MID LEVEL DRY SLOT LOOKS TO BE MOVING THROUGH THE CWA THIS
EVENING...IT APPEARS THERE WILL BE SUFFICIENT LOW LEVEL
MOISTURE/CONVERGENCE/CYCLONIC FLOW TO MAINTAIN SOME LIGHT
RAINFALL OR DRIZZLE AT THE VERY LEAST. COLD ADVECTION AND WESTERLY
WINDS DEVELOPING LATE TONIGHT WILL ATTEMPT TO DRY THE LOW LEVELS
OUT...BUT WITH STRENGTHENING/LOWERING INVERSION ON TUESDAY...WOULD
EXPECT SUFFICIENT MOISTURE TRAPPED UNDERNEATH TO MAINTAIN CLOUDY
SKIES INTO THE AFTERNOON HOURS...WITH POSSIBLE CLEARING WORKING UP
FROM THE SOUTH LATE.
AMPLIFYING LONGWAVE TROUGH AXIS OVER CENTRAL NORTH AMERICA ON
WEDNESDAY...RESULTING IN VERY STRONG/DEEP SOUTHWEST FLOW
PUMPING WARM AND MOIST AIRMASS INTO LOWER MICHIGAN DURING THE DAY.
LOW LEVEL JET PROGGED TO EXCEED 60 KNOTS. 925 MB TEMPS FORECASTED TO
RISE INTO THE LOWER TEENS...SUGGESTING HIGH TEMPERATURES POTENTIALLY
RISING INTO THE 60S. HOWEVER...SATURATION LOOKS TO BE OCCURRING WITH
THE ISENTROPIC ASCENT/MOISTURE TRANSPORT...AS 850 MB DEW PTS RISE TO
RECORD SETTING 10 C PER 00Z EURO...AND SEEMS LIKELY RAIN WILL
DEVELOP...LIMITING THE MAXES A BIT. EVEN A CONSERVATIVE MAX
FORECAST IN THE 55 TO 60 DEGREE RANGE WILL SET US UP TO BREAK THE
DAILY RECORDS FOR DECEMBER 23RD:
DTW 56 (1893)
FNT 55 (1982)
MBS 53 (1982)
MORE COMPELLING EVIDENCE WITH LI`S DROPPING BELOW ZERO TO INCLUDE A
THUNDER MENTION INTO WEDNESDAY EVENING AS STRENGTHENING/AGGRESSIVE
6 HR 500 MB HEIGHT FALLS (-70 TO -90 M) CENTER WORKS THROUGH THE
CENTRAL GREAT LAKES.
WITH MAIN UPPER WAVE RACING NORTHEAST INTO QUEBEC THURSDAY
MORNING...AND VEERING WINDS FAILING TO BECOME FULLY WEST-
NORTHWEST...AMOUNT OF COLD ADVECTION SPILLING INTO SOUTHERN LOWER
MICHIGAN LATE WEDNESDAY NIGHT INTO THURSDAY IS IN QUESTION. VERY
TIGHT BAROCLINIC ZONE AT 925/850 MB WILL MAKE FOR SENSITIVE
TEMPERATURE FORECAST...BUT ASSUMING 925 MB TEMPS REMAIN A COUPLE
DEGREES ABOVE ZERO...TEMPERATURES SHOULD HAVE NO PROBLEM
HOLDING IN THE UPPER 40S TO LOWER 50S.
MARINE...
AN ELONGATED AREA OF SURFACE LOW PRESSURE WILL LIFT NORTHEASTWARD
THROUGH THE WESTERN AND CENRAL GREAT LAKES TODAY. A MODEST
SOUTHWESTERLY FLOW OF 15 TO 25 KNOTS WILL REMAIN IN PLACE FROM THE
CENTRAL LAKE HURON BASIN SOUTHWARD THROUGH MUCH OF THIS AFTERNOON.
THE STRONGEST WINDS...POTENTIALLY REACHING 30 KNOTS FOR A TIME...ARE
EXPECTED TO BE IN PLACE FROM LAKE ST CLAIR SOUTHWARD INCLUDING THE
MICHIGAN WATERS OF LAKE ERIE. SMALL CRAFT ADVISORIES REMAIN IN
EFFECT FOR THE SOUTHERN MARINE AREAS TO ACCOUNT FOR THE MODERATE
PRESSURE GRADIENT. SURFACE WINDS WILL THEN VEER TO THE WEST IN THE
WAKE OF THE SURFACE LOW PRESSURE TONIGHT AS A WEAK SURFACE RIDGE
PASSES THROUGH THE REGION. A RETURN TO INCREASING MODERATE SOUTHERLY
FLOW IS EXPECTED ON WEDNESDAY AS THE NEXT LOW PRESSURE SYSTEM
ORGANIZES OVER THE NATIONS HEARTLAND.
HYDROLOGY...
AN AREA OF UPPER LEVEL LOW PRESSURE WILL DRAW MOISTURE NORTHWARD
INTO SOUTHEASTERN MICHIGAN THIS MORNING. WIDESPREAD LIGHT TO
MODERATE RAIN WILL DEVELOP BEFORE DAYBREAK AND PERSIST THROUGHOUT
MUCH OF THE DAY. HIGH CONFIDENCE EXISTS FOR RAINFALL AMOUNTS OF
BETWEEN .25 AND .50 OF AN INCH. INDICATIONS ARE THE HIGHER END OF
THE RANGE WILL OCCUR NORTH OF THE I 69 CORRIDOR.
A STRONG WARM FRONT WILL LIFT INTO THE GREAT LAKES REGION ON
WEDNESDAY AHEAD OF THE NEXT DYNAMIC UPPER LEVEL TROUGH. A RETURN OF
RECORD BREAKING WARM TEMPERATURES AND MOISTURE WILL LEAD TO ANOTHER
WIDESPREAD PRECIPITATION EVENT. LATEST FORECAST INFORMATION SUGGESTS
AS MUCH AS .50 TO .75 OF INCH OF RAINFALL WILL BE POSSIBLE WEDNESDAY
AFTERNOON THROUGH THURSDAY NIGHT.
WITH THE TIME SEPARATION BETWEEN EVENTS AND DRY ANTECEDENT
CONDITIONS...LITTLE CONCERN FOR FLOODING POTENTIAL EXISTS.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR LCZ460.
MICHIGAN WATERS OF LAKE ERIE...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR LEZ444.
&&
$$
AVIATION.....CB
DISCUSSION...SF
MARINE.......CB
HYDROLOGY....CB
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
315 AM EST MON DEC 21 2015
.DISCUSSION...
COPIOUS AMOUNT OF UPPER LEVEL ENERGY DIVING SOUTHEAST THROUGH THE
PACIFIC NORTHWEST OVER THE NEXT SEVERAL DAYS...MAINTAINING A WET AND
ACTIVE PATTERN...WITH RECORD WARMTH LIKELY OVER SOUTHEAST MICHIGAN ON
WEDNESDAY.
PACIFIC PINEAPPLE CONNECTION ESTABLISHED THIS MORNING JUST EAST
OF MISSISSIPPI RIVER VALLEY...AND RAIN SHIELD SHOULD CONTINUE TO
BLOSSOM AS UPPER LEVEL WAVE/PV CENTER NEAR KANSAS CITY EARLY THIS
MORNING TRACKS THROUGH FAR SOUTHERN LOWER MICHIGAN THIS AFTERNOON.
WITH FAVORABLE MOISTURE AND FORCING...EXPECTING RAINFALL TOTALS
CLOSING IN ON HALF AN INCH...ESPECIALLY IF WE CAN GET ANY CONVECTIVE
ELEMENTS GOING...AS SHOWALTER INDEX DROPS DOWN TO AROUND 1 C. DID
NOTE SOME LIGHTNING STRIKES OVER EASTERN WISCONSIN YESTERDAY
EVENING...AS WELL AS ONGOING STRIKES UNDERNEATH THE CENTER...BUT
LEFT MENTION OUT OF THE FORECAST IN LINE WITH SPC DAY 1.
VERY STRONG LOW LEVEL WINDS FIELDS AROUND THIS MORNING...PARTIALLY
ARTIFACT OF SURFACE/NEAR SURFACE STABLE LAYER...AND EXPECTING LIMITED
MIXING TODAY...IN LINE WITH RAP SOUNDINGS TO KEEP WIND GUSTS IN THE
25 TO 30 KNOT RANGE...MAINLY SOUTH TOWARD OHIO BORDER...AS SURFACE
TEMPERATURES DON`T BUDGE MUCH FROM PRESENT LOW/MID 40 VALUES.
ALTHOUGH MID LEVEL DRY SLOT LOOKS TO BE MOVING THROUGH THE CWA THIS
EVENING...IT APPEARS THERE WILL BE SUFFICIENT LOW LEVEL
MOISTURE/CONVERGENCE/CYCLONIC FLOW TO MAINTAIN SOME LIGHT
RAINFALL OR DRIZZLE AT THE VERY LEAST. COLD ADVECTION AND WESTERLY
WINDS DEVELOPING LATE TONIGHT WILL ATTEMPT TO DRY THE LOW LEVELS
OUT...BUT WITH STRENGTHENING/LOWERING INVERSION ON TUESDAY...WOULD
EXPECT SUFFICIENT MOISTURE TRAPPED UNDERNEATH TO MAINTAIN CLOUDY
SKIES INTO THE AFTERNOON HOURS...WITH POSSIBLE CLEARING WORKING UP
FROM THE SOUTH LATE.
AMPLIFYING LONGWAVE TROUGH AXIS OVER CENTRAL NORTH AMERICA ON
WEDNESDAY...RESULTING IN VERY STRONG/DEEP SOUTHWEST FLOW
PUMPING WARM AND MOIST AIRMASS INTO LOWER MICHIGAN DURING THE DAY.
LOW LEVEL JET PROGGED TO EXCEED 60 KNOTS. 925 MB TEMPS FORECASTED TO
RISE INTO THE LOWER TEENS...SUGGESTING HIGH TEMPERATURES POTENTIALLY
RISING INTO THE 60S. HOWEVER...SATURATION LOOKS TO BE OCCURRING WITH
THE ISENTROPIC ASCENT/MOISTURE TRANSPORT...AS 850 MB DEW PTS RISE TO
RECORD SETTING 10 C PER 00Z EURO...AND SEEMS LIKELY RAIN WILL
DEVELOP...LIMITING THE MAXES A BIT. EVEN A CONSERVATIVE MAX
FORECAST IN THE 55 TO 60 DEGREE RANGE WILL SET US UP TO BREAK THE
DAILY RECORDS FOR DECEMBER 23RD:
DTW 56 (1893)
FNT 55 (1982)
MBS 53 (1982)
MORE COMPELLING EVIDENCE WITH LI`S DROPPING BELOW ZERO TO INCLUDE A
THUNDER MENTION INTO WEDNESDAY EVENING AS STRENGTHENING/AGGRESSIVE
6 HR 500 MB HEIGHT FALLS (-70 TO -90 M) CENTER WORKS THROUGH THE
CENTRAL GREAT LAKES.
WITH MAIN UPPER WAVE RACING NORTHEAST INTO QUEBEC THURSDAY
MORNING...AND VEERING WINDS FAILING TO BECOME FULLY WEST-
NORTHWEST...AMOUNT OF COLD ADVECTION SPILLING INTO SOUTHERN LOWER
MICHIGAN LATE WEDNESDAY NIGHT INTO THURSDAY IS IN QUESTION. VERY
TIGHT BAROCLINIC ZONE AT 925/850 MB WILL MAKE FOR SENSITIVE
TEMPERATURE FORECAST...BUT ASSUMING 925 MB TEMPS REMAIN A COUPLE
DEGREES ABOVE ZERO...TEMPERATURES SHOULD HAVE NO PROBLEM
HOLDING IN THE UPPER 40S TO LOWER 50S.
&&
.MARINE...
AN ELONGATED AREA OF SURFACE LOW PRESSURE WILL LIFT NORTHEASTWARD
THROUGH THE WESTERN AND CENRAL GREAT LAKES TODAY. A MODEST
SOUTHWESTERLY FLOW OF 15 TO 25 KNOTS WILL REMAIN IN PLACE FROM THE
CENTRAL LAKE HURON BASIN SOUTHWARD THROUGH MUCH OF THIS AFTERNOON.
THE STRONGEST WINDS...POTENTIALLY REACHING 30 KNOTS FOR A TIME...ARE
EXPECTED TO BE IN PLACE FROM LAKE ST CLAIR SOUTHWARD INCLUDING THE
MICHIGAN WATERS OF LAKE ERIE. SMALL CRAFT ADVISORIES REMAIN IN
EFFECT FOR THE SOUTHERN MARINE AREAS TO ACCOUNT FOR THE MODERATE
PRESSURE GRADIENT. SURFACE WINDS WILL THEN VEER TO THE WEST IN THE
WAKE OF THE SURFACE LOW PRESSURE TONIGHT AS A WEAK SURFACE RIDGE
PASSES THROUGH THE REGION. A RETURN TO INCREASING MODERATE SOUTHERLY
FLOW IS EXPECTED ON WEDNESDAY AS THE NEXT LOW PRESSURE SYSTEM
ORGANIZES OVER THE NATIONS HEARTLAND.
&&
.HYDROLOGY...
AN AREA OF UPPER LEVEL LOW PRESSURE WILL DRAW MOISTURE NORTHWARD
INTO SOUTHEASTERN MICHIGAN THIS MORNING. WIDESPREAD LIGHT TO
MODERATE RAIN WILL DEVELOP BEFORE DAYBREAK AND PERSIST THROUGHOUT
MUCH OF THE DAY. HIGH CONFIDENCE EXISTS FOR RAINFALL AMOUNTS OF
BETWEEN .25 AND .50 OF AN INCH. INDICATIONS ARE THE HIGHER END OF
THE RANGE WILL OCCUR NORTH OF THE I 69 CORRIDOR.
A STRONG WARM FRONT WILL LIFT INTO THE GREAT LAKES REGION ON
WEDNESDAY AHEAD OF THE NEXT DYNAMIC UPPER LEVEL TROUGH. A RETURN OF
RECORD BREAKING WARM TEMPERATURES AND MOISTURE WILL LEAD TO ANOTHER
WIDESPREAD PRECIPITATION EVENT. LATEST FORECAST INFORMATION SUGGESTS
AS MUCH AS .50 TO .75 OF INCH OF RAINFALL WILL BE POSSIBLE WEDNESDAY
AFTERNOON THROUGH THURSDAY NIGHT.
WITH THE TIME SEPARATION BETWEEN EVENTS AND DRY ANTECEDENT
CONDITIONS...LITTLE CONCERN FOR FLOODING POTENTIAL EXISTS.
&&
.AVIATION...ISSUED 1156 PM EST SUN DEC 20 2015
WIND GUSTS HAVE REMAINED FAIRLY ELEVATED THIS EVENING. SUSPECT THAT
ONCE RAIN MOVES IN THE BOUNDARY LAYER WILL COOL ENOUGH TO SUPPRESS
SOME OF THE GUSTINESS. THE DTX VAD WIND PROFILE CONTINUES TO SUPPORT
50 TO 55 KNOTS IN THE 1500 TO 2000 FT LAYER SHOWN IN LATEST MODEL
SOLUTIONS. THUS...THE LOW LEVEL WIND SHEAR WILL REMAIN IN THE TAFS
THROUGH DAYBREAK. RAIN IS QUICKLY ADVANCING IN FROM THE SOUTHWEST.
THE RAIN WILL OVERSPREAD THE TERMINALS FROM 06Z TO ROUGHLY 09Z.
CEILINGS WILL INITIALLY BE IN THE LOW END VFR RANGE. COOLING IN THE
LOW LEVELS AND ADDITIONAL MOISTURE ADVECTION DURING THE MORNING
SHOULD QUICKLY LOWER CEILINGS TO IFR. MODEL SOUNDINGS SUGGEST THIS
WILL OCCUR RATHER ABRUPTLY AROUND OR SHORTLY AFTER 12Z.
FOR DTW...THE SOUTH WINDS SHOULD DECREASE A BIT AS THE RAIN MOVES IN
/08-10Z TIME FRAME/. THIS SUGGESTS CONDITIONS WILL TRANSITION FROM
THAT OF LOW LEVEL CONVECTIVE TURBULENCE TO MORE PURE LOW LEVEL WIND
SHEAR. IT HAS THE POTENTIAL TO BE RATHER GUSTY /SOUTH WINDS/ MON
AFTERNOON. THE EARLY DAY RAINFALL MAY HOWEVER CAUSE THE BOUNDARY
LAYER TO REMAIN A LITTLE MORE STABLE THROUGH THE DAY. THIS WILL
SUPPORT WINDS A TOUCH ON THE CONSERVATIVE SIDE.
//DTW THRESHOLD PROBABILITIES...
* HIGH CONFIDENCE IN CEILINGS AOB 5000 FEET TODAY.
* HIGH CONFIDENCE IN RAIN AS PRECIPITATION TYPE.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR LCZ460.
MICHIGAN WATERS OF LAKE ERIE...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR LEZ444.
&&
$$
DISCUSSION...SF
MARINE.......CB
HYDROLOGY....CB
AVIATION.....SC
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS DULUTH MN
902 PM CST TUE DEC 22 2015
.UPDATE...
ISSUED AT 902 PM CST TUE DEC 22 2015
MINIMUM TEMPERATURE FORECAST HAS BEEN MET AND TEMPS CONINTUE TO
WARM. HAVE ADJUSTED THE FORECAST TO ACCOUNT FOR SLOWLY RISING
TEMPS TONIGHT. WITH THE WARM TEMPS TO START WEDNESDAY...WITH
SEVERAL SPOTS ABOVE FREEZING...REMOVED THE MENTION OF FREEZING
DRIZZLE AND SLEET.
UPDATE ISSUED AT 746 PM CST TUE DEC 22 2015
SFC LOW CENTER HAS MOVED INTO SE ND AND THE LIGHT SNOW HAS ENDED.
SFC TEMPS HAVE WARMED TO 32F OR WARMER IN SEVERAL SPOTS. AS A
RESULT...HAVE REMOVED THE MENTION OF FREEZING
DRIZZLE...SLEET...DRIZZLE. STILL EXPECTING THE NEXT ROUND OF SNOW
TO DEVELOP IN NW WI AFTER MIDNIGHT. HOWEVER...SHORT TERM HIRES
MODELS INCLUDING THE DLH WRF AND HRRR ARE POINTING TO THE
POSSIBILITY OF ALL RAIN IN NW WI OR A RAIN SNOW MIX. WILL KEEP THE
PREDOMINATE PTYPE AS SNOW. MADE SOME OTHER MINOR ADJUSTMENTS.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 413 PM CST TUE DEC 22 2015
THIS AFTERNOON A COMPACT SHORTWAVE TROF STRETCHED FROM NORTHEAST
MONTANA INTO EASTERN SOUTH DAKOTA. THE TROF WAS ACCOMPANIED BY A
POTENT CYCLONIC VORTICITY ANOMALY AND STRONG WARM AIR ADVECTION.
AT THE SURFACE A CLOSE LOW WAS CENTERED OVER NORTHERN SOUTH DAKOTA
WITH A TROF OF LOW PRESSURE STRETCHING NORTHEASTWARD INTO
NORTHWEST ONTARIO. LIGHT...TO OCCASIONALLY MODERATE...SNOW WAS
FALLING OVER EASTERN NORTH DAKOTA AND NORTHWEST MINNESOTA. SNOW
SHOWERS AND AREAS OF FREEZING DRIZZLE STRETCHED FARTHER EASTWARD
INTO NORTHEAST MINNESOTA.
THE SHORTWAVE TROF AND ASSOCIATED SURFACE LOW WILL LIFT THROUGH
NORTHWEST MINNESOTA AND INTO ONTARIO TONIGHT. PATCHY AREAS OF
FREEZING DRIZZLE ARE EXPECTED TO CONTINUE OVER MUCH OF NORTHEAST
MINNESOTA THANKS IN LARGE PART TO A WEDGE OF DRY AIR BETWEEN THE
GLACIATED CLOUDS ALOFT AND THE SATURATED NEAR-SURFACE LAYER. THE
FREEZING DRIZZLE WILL CHANGE TO OR MIX WITH LIGHT SNOW OVER MY
WESTERN ZONES AS THE SYSTEM PASSES BY. SNOW ACCUMULATION SHOULD
BE LIGHT...AS THE BEST FORCING FOR ASCENT WILL QUICKLY MOVE
THROUGH ANY SPECIFIC LOCATION. LOOK FOR SNOW TOTALS IN THE DUSTING
TO 2 INCH RANGE...WITH THE HIGHEST ACCUMULATION OVER WESTERN
PORTIONS OF KOOCHICHING COUNTY.
ATTENTION THEN SHIFTS TO WEDNESDAY...AS A SECONDARY AREA OF LOW
PRESSURE LIFTS FROM THE CENTRAL PLAINS INTO NORTHERN WISCONSIN BY
LATE WEDNESDAY AFTERNOON. DETERMINISTIC AND ENSEMBLE GUIDANCE IS
ALL POINTING TOWARD STRONG WARM AIR ADVECTION AHEAD OF AND EAST OF
THE LOW...AND SURFACE TEMPERATURES OVER WISCONSIN CLIMBING INTO
THE UPPER 30S TO LOW 40S. WITH THE WARM ADVECTION AND ISENTROPIC
ASCENT...AND ASSOCIATED PRECIPITATION... AM CONCERNED GUIDANCE MAY
BE TRENDING TOO WARM WITH SFC TEMPS. HAVE TRENDED CLOSER TO THE
DETERMINISTIC NAM GUIDANCE FOR TEMPS ON WEDNESDAY...WHICH YIELDS
30-35F FOR MAX TEMPS.
PRECIP TYPES ARE A CHALLENGE FOR WEDNESDAY. THE AIRMASS WILL BE
COLD ENOUGH FOR SNOW...WITH PATCHY FREEZING DRIZZLE...OVER MY
MINNESOTA ZONES. HOWEVER...ASCENT IS MUCH WEAKER AND DO NOT EXPECT
MORE THAN FLURRIES AND FREEZING DRIZZLE THROUGH THE AFTERNOON.
WHERE PRECIPITATION IS LIKELY TO BE HEAVIEST...MAINLY FROM THE
TWIN PORTS SOUTH ALONG I-35 AND EASTWARD...A WINTRY MIX OF SNOW...
SLEET...AND RAIN SEEMS FAVORED. SHOULD TEMPERATURES REMAIN
COOLER...AND IF THE ADVECTION ALOFT TRENDS CLOSER TO THE GFS
SOLUTION...FREEZING RAIN WOULD BE MORE OF A CONCERN. BETWEEN THE
SLEET AND SNOW POTENTIAL...THERE IS A THREAT FOR SOME ICY ROADS.
DUE TO THE LINGERING UNCERTAINTY IN PTYPE AND TEMPERATURES...HELD
OFF ON AN ADVISORY FOR NOW BUT ONE MAY BE NEEDED BY MORNING.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 413 PM CST TUE DEC 22 2015
BY WEDNESDAY EVENING THE SFC LOW WILL BE RACING OFF TO THE
NORTHEAST...AND ITS WHEREABOUTS DEPEND UPON THE MODEL AND HAVE
USED THE GFS/ECMWF COMPROMISE OF THE SLOWER MOVEMENT. THE
CYCLONIC FLOW AROUND THE LOW WILL KEEP SNOW SHOWERS GOING INTO
THURSDAY MORNING. THEY WILL END IN THE AFTERNOON. HOWEVER...THERE
COULD BE SOME ISOLATED LAKE EFFECT SNOW SHOWERS ALONG THE SOUTH
SHORE AS 8H TEMPS OF -8C TO -10C BLOW ACROSS A +5C LAKE SUPERIOR.
HOWEVER...A WEST COMPONENT DOES NOT GIVE A VERY LONG FETCH AND IF
ANY SNOW SHOWERS DO OCCUR...THEY WILL BE ISOLATED AND LIGHT.
BROAD UPPER LEVEL TROFINESS WILL DOMINATE THE FLOW THROUGH THE
EXTENDED PERIOD. THIS WILL KEEP THE NORTHLAND IN A MILD SOUTHWEST OR
WEST AIRFLOW. ONCE THE CURRENT LOW PRESSURE PASSES THERE WILL BE
LITTLE PRECIPITATION UNTIL ABOUT SATURDAY WHEN ANOTHER LOW WILL MOVE
NORTH INTO IOWA AND ILLINOIS. AND ANOTHER ONE MAY BRING SNOW NEXT
TUESDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 534 PM CST TUE DEC 22 2015
A SFC LOW WAS MOVING INTO ND AT THE OUTSET OF THE FORECAST. THIS
RESULTED IN A SOUTHERLY FLOW OVER THE TERMINALS. PLENTY OF
IFR/MVFR CIGS WERE AFFECTING THE AREA WITH SOME PATCHY BR AND
FLURRIES. AS THE SFC LOW TRACKS NEWD THROUGH THE REST OF THE
FORECAST PERIOD...SOME PATCHY -FZDZ AND FLURRIES MAY BE FOUND.
AFTER 10Z...LIGHT SNOW WILL BEGIN TO AFFECT THE TERMINALS WITH THE
LOWEST VSBYS IN MODERATE SNOW...POSSIBLY HEAVY AT TIMES...AFFECTING
HYR AND TO A LESSER EXTENT AT DLH. OTHER TERMINALS WILL NOT HAVE
SUCH RESTRICTIVE VSBYS. THIS WILL PERSIST THROUGH THE FORECAST.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 30 32 22 25 / 30 70 30 10
INL 30 32 18 22 / 10 20 30 20
BRD 30 32 19 24 / 10 20 20 10
HYR 32 34 24 28 / 70 100 50 10
ASX 32 34 27 30 / 50 90 60 20
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
LS...SMALL CRAFT ADVISORY UNTIL 6 AM CST WEDNESDAY FOR LSZ140-141.
&&
$$
UPDATE...GSF
SHORT TERM...HUYCK
LONG TERM...CLC
AVIATION...GSF
AREA FORECAST DISCUSSION
NWS DULUTH MN
746 PM CST TUE DEC 22 2015
.UPDATE...
ISSUED AT 746 PM CST TUE DEC 22 2015
SFC LOW CENTER HAS MOVED INTO SE ND AND THE LIGHT SNOW HAS ENDED.
SFC TEMPS HAVE WARMED TO 32F OR WARMER IN SEVERAL SPOTS. AS A
RESULT...HAVE REMOVED THE MENTION OF FREEZING
DRIZZLE...SLEET...DRIZZLE. STILL EXPECTING THE NEXT ROUND OF SNOW
TO DEVELOP IN NW WI AFTER MIDNIGHT. HOWEVER...SHORT TERM HIRES
MODELS INCLUDING THE DLH WRF AND HRRR ARE POINTING TO THE
POSSIBILITY OF ALL RAIN IN NW WI OR A RAIN SNOW MIX. WILL KEEP THE
PREDOMINATE PTYPE AS SNOW. MADE SOME OTHER MINOR ADJUSTMENTS.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 413 PM CST TUE DEC 22 2015
THIS AFTERNOON A COMPACT SHORTWAVE TROF STRETCHED FROM NORTHEAST
MONTANA INTO EASTERN SOUTH DAKOTA. THE TROF WAS ACCOMPANIED BY A
POTENT CYCLONIC VORTICITY ANOMALY AND STRONG WARM AIR ADVECTION.
AT THE SURFACE A CLOSE LOW WAS CENTERED OVER NORTHERN SOUTH DAKOTA
WITH A TROF OF LOW PRESSURE STRETCHING NORTHEASTWARD INTO
NORTHWEST ONTARIO. LIGHT...TO OCCASIONALLY MODERATE...SNOW WAS
FALLING OVER EASTERN NORTH DAKOTA AND NORTHWEST MINNESOTA. SNOW
SHOWERS AND AREAS OF FREEZING DRIZZLE STRETCHED FARTHER EASTWARD
INTO NORTHEAST MINNESOTA.
THE SHORTWAVE TROF AND ASSOCIATED SURFACE LOW WILL LIFT THROUGH
NORTHWEST MINNESOTA AND INTO ONTARIO TONIGHT. PATCHY AREAS OF
FREEZING DRIZZLE ARE EXPECTED TO CONTINUE OVER MUCH OF NORTHEAST
MINNESOTA THANKS IN LARGE PART TO A WEDGE OF DRY AIR BETWEEN THE
GLACIATED CLOUDS ALOFT AND THE SATURATED NEAR-SURFACE LAYER. THE
FREEZING DRIZZLE WILL CHANGE TO OR MIX WITH LIGHT SNOW OVER MY
WESTERN ZONES AS THE SYSTEM PASSES BY. SNOW ACCUMULATION SHOULD
BE LIGHT...AS THE BEST FORCING FOR ASCENT WILL QUICKLY MOVE
THROUGH ANY SPECIFIC LOCATION. LOOK FOR SNOW TOTALS IN THE DUSTING
TO 2 INCH RANGE...WITH THE HIGHEST ACCUMULATION OVER WESTERN
PORTIONS OF KOOCHICHING COUNTY.
ATTENTION THEN SHIFTS TO WEDNESDAY...AS A SECONDARY AREA OF LOW
PRESSURE LIFTS FROM THE CENTRAL PLAINS INTO NORTHERN WISCONSIN BY
LATE WEDNESDAY AFTERNOON. DETERMINISTIC AND ENSEMBLE GUIDANCE IS
ALL POINTING TOWARD STRONG WARM AIR ADVECTION AHEAD OF AND EAST OF
THE LOW...AND SURFACE TEMPERATURES OVER WISCONSIN CLIMBING INTO
THE UPPER 30S TO LOW 40S. WITH THE WARM ADVECTION AND ISENTROPIC
ASCENT...AND ASSOCIATED PRECIPITATION... AM CONCERNED GUIDANCE MAY
BE TRENDING TOO WARM WITH SFC TEMPS. HAVE TRENDED CLOSER TO THE
DETERMINISTIC NAM GUIDANCE FOR TEMPS ON WEDNESDAY...WHICH YIELDS
30-35F FOR MAX TEMPS.
PRECIP TYPES ARE A CHALLENGE FOR WEDNESDAY. THE AIRMASS WILL BE
COLD ENOUGH FOR SNOW...WITH PATCHY FREEZING DRIZZLE...OVER MY
MINNESOTA ZONES. HOWEVER...ASCENT IS MUCH WEAKER AND DO NOT EXPECT
MORE THAN FLURRIES AND FREEZING DRIZZLE THROUGH THE AFTERNOON.
WHERE PRECIPITATION IS LIKELY TO BE HEAVIEST...MAINLY FROM THE
TWIN PORTS SOUTH ALONG I-35 AND EASTWARD...A WINTRY MIX OF SNOW...
SLEET...AND RAIN SEEMS FAVORED. SHOULD TEMPERATURES REMAIN
COOLER...AND IF THE ADVECTION ALOFT TRENDS CLOSER TO THE GFS
SOLUTION...FREEZING RAIN WOULD BE MORE OF A CONCERN. BETWEEN THE
SLEET AND SNOW POTENTIAL...THERE IS A THREAT FOR SOME ICY ROADS.
DUE TO THE LINGERING UNCERTAINTY IN PTYPE AND TEMPERATURES...HELD
OFF ON AN ADVISORY FOR NOW BUT ONE MAY BE NEEDED BY MORNING.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 413 PM CST TUE DEC 22 2015
BY WEDNESDAY EVENING THE SFC LOW WILL BE RACING OFF TO THE
NORTHEAST...AND ITS WHEREABOUTS DEPEND UPON THE MODEL AND HAVE
USED THE GFS/ECMWF COMPROMISE OF THE SLOWER MOVEMENT. THE
CYCLONIC FLOW AROUND THE LOW WILL KEEP SNOW SHOWERS GOING INTO
THURSDAY MORNING. THEY WILL END IN THE AFTERNOON. HOWEVER...THERE
COULD BE SOME ISOLATED LAKE EFFECT SNOW SHOWERS ALONG THE SOUTH
SHORE AS 8H TEMPS OF -8C TO -10C BLOW ACROSS A +5C LAKE SUPERIOR.
HOWEVER...A WEST COMPONENT DOES NOT GIVE A VERY LONG FETCH AND IF
ANY SNOW SHOWERS DO OCCUR...THEY WILL BE ISOLATED AND LIGHT.
BROAD UPPER LEVEL TROFINESS WILL DOMINATE THE FLOW THROUGH THE
EXTENDED PERIOD. THIS WILL KEEP THE NORTHLAND IN A MILD SOUTHWEST OR
WEST AIRFLOW. ONCE THE CURRENT LOW PRESSURE PASSES THERE WILL BE
LITTLE PRECIPITATION UNTIL ABOUT SATURDAY WHEN ANOTHER LOW WILL MOVE
NORTH INTO IOWA AND ILLINOIS. AND ANOTHER ONE MAY BRING SNOW NEXT
TUESDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 534 PM CST TUE DEC 22 2015
A SFC LOW WAS MOVING INTO ND AT THE OUTSET OF THE FORECAST. THIS
RESULTED IN A SOUTHERLY FLOW OVER THE TERMINALS. PLENTY OF
IFR/MVFR CIGS WERE AFFECTING THE AREA WITH SOME PATCHY BR AND
FLURRIES. AS THE SFC LOW TRACKS NEWD THROUGH THE REST OF THE
FORECAST PERIOD...SOME PATCHY -FZDZ AND FLURRIES MAY BE FOUND.
AFTER 10Z...LIGHT SNOW WILL BEGIN TO AFFECT THE TERMINALS WITH THE
LOWEST VSBYS IN MODERATE SNOW...POSSIBLY HEAVY AT TIMES...AFFECTING
HYR AND TO A LESSER EXTENT AT DLH. OTHER TERMINALS WILL NOT HAVE
SUCH RESTRICTIVE VSBYS. THIS WILL PERSIST THROUGH THE FORECAST.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 30 32 22 25 / 30 70 30 10
INL 30 32 18 22 / 10 20 30 20
BRD 30 32 19 24 / 10 20 20 10
HYR 32 34 24 28 / 70 100 50 10
ASX 32 34 27 30 / 50 90 60 20
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
LS...SMALL CRAFT ADVISORY UNTIL 6 AM CST WEDNESDAY FOR LSZ140-141.
&&
$$
UPDATE...GSF
SHORT TERM...HUYCK
LONG TERM...CLC
AVIATION...GSF
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
943 PM CST TUE DEC 22 2015
.UPDATE:
Issued at 927 PM CST Tue Dec 22 2015
A few adjustments to the forecast tonight...mainly to try and time
clouds a little better and to reflect precip trends shown by the
latest short range guidance. Both the RAP and HRRR are delaying
the onset of precipitation until after 10-11Z across much of the
area, so have cut back the PoPs a bit...keeping likelies out of
the forecast until 11-12Z, and then only in far southern zones and
northwest zones where guidance is showing accumulating precip.
Quickly ramp up to likely and categorical after 12Z.
Of second concern, watching fog inch toward our southeast CWFA
border. Will continue to monitor, but I may have to issue a dense
fog advisory before midnight if the fog continues to spread
northeast.
Carney
&&
.SHORT TERM: (Through Late Tonight)
Issued at 332 PM CST Tue Dec 22 2015
Over the last few hour the low stratus has eroded rapidly in most of
the MO counties in our CWA. However, some lower clouds are
lingering over our s IL counties, with another, more persistent and
thicker cloud deck remaining anchored in the post frontal AMS from
se MO into the Ohio Valley. With a s/se component to the low level
flow continuing overnight believe that lower clouds will expand
across the eastern half of the CWA during the evening through a
combination of redevelopment with noctural cooling of the boundary
layer and/or nwd advection of Ohio Valley cloud deck. Over central
MO, the higher level cloudiness of this evening should also give way
to lower clouds after midnight as increasing southerly flow/low
level jet causes low level moisture to surge into the area.
The resultant moisture transport and isentropic ascent, combined
with larger scale UVV associated with lead shortwave ejecting ahead
of central Plains trof, should allow showers to develop after 06z in
a N/S band west of the Mississippi River that will gradually
increase in coverage and expand east with time. Although forecast
instability looks fairly meager the low level advection profile does
lead to decent lower/mid level lapse rates that would support the
idea of some elevated convection. For now I`ve maintained slight
chance of thunderstorms because of this, but evening shift will
certainly have to monitor this.
Temperatures may dip briefly this evening, before the combo of
increasing winds and clouds cause steady or slowly rising temps
during the overnight hours.
Truett
.LONG TERM: (Wednesday through Next Tuesday)
Issued at 332 PM CST Tue Dec 22 2015
(Wednesday)
Very active and unsettled weather on Wednesday as sfc low deepends
across eastern Kansas early Wednesday morning and tracks toward
southern Iowa by midday. Expect north/south oriented band of rain
showers w/ embedded thunderstorms to sweep through the area. Should
be a break during the late morning hours/early afternoon before at
least scattered thunderstorms develop along the trailing cold front.
Threat of severe thunderstorms has increased over the past 24-48
hours due to higher forecast instability. NWP guidance suggests
SBCAPE values of 500-1000+ J/kg as a break in the rainfall and
possible breaks in the clouds would help to increase the
instability...potentially even further than what is currently being
advertised. Deep-layer shear of 50-70 knots combined with the
forecast instability would be more than enough to support all forms
of severe weather. Supercells are also quite possible along/ahead of
front as deep-layer shear vector is oriented roughly 30 degrees to
cold front. Tornado threat is increased due to very high 0-1km shear
and helicity...but south/southwest sfc winds and relatively high
LCL values could be inhibiting factors to tornadic development.
(Thursday through Christmas Day)
A relatively quiet quiet period will come between Thursday and
Christmas Day. Mostly dry weaher is expected with the exception
being Christmas Day acrosss the southeastern portion of the CWA with
a chance of showers as warm advection increases at lower levels.
Temperatures both day/night will be cooler than Wednesday...but
still well above normal levels for the end of December.
(Christmas Night through Monday)
Frontal boundary that had stalled south of the CWA will move back
northward Christmas night and Saturday and bring a round of showers
and embedded thunderstorms to the region. The retreating warm front
is then forecast to stall out somewhere across the CWA and provide
the focus for widespread showers/thunderstorms through Saturday
night with moderate to potentially heavy rainfall rates. Frontal
boundary will sag back southward by Sunday morning. Temperatures
will cool and instability...even aloft...becomes negligible. Have
removed thunder wording for the Sunday period but still have
likely/categorical PoPs north of the boundary for light/moderate
rain. Sunday looks like a real chilly/raw day with high temperatures
foercast to be only in the 40s with northeast winds and rain. Sfc
system will occlude near the Arklatex region late on Sunday and
track toward north-central Missouri by Monday afternoon. Another
round of moderate to potentially heavy rainfall is likely to occur
late Sunday night/early Monday along with embedded thunderstorms
also possible. An early look at total rainfall for this event looks
to be on the order of 3 to 6 inches across the southeastern half of
the CWA...with locally higher amounts possible due to convection.
This rainfall will likely lead to additional flooding along area
rivers/streams. For more details...please see the hydrologic outlook
(ESF).
(Tuesday)
The atmosphere looks to finally quiet down next Tuesday as the
previous system moves out into southeastern Canada. Temepratures
will remain above normal on Tuesday with highs in the 40s. Some
signs of a pattern shift heading toward the New Year as longwave
ridging builds near the west coast. If this indeed occurs...at
turn toward near or below normal temperatures and drier conditions
would be more likely.
Gosselin
&&
.AVIATION: (For the 00z TAFs through 00z Wednesday Evening)
Issued at 702 PM CST Tue Dec 22 2015
Predominantly IFR CIGs accelerating their movement to the NW will
envelope the STL metro TAF sites by 01z and eventually push on to
UIN and COU later tonight, but may be a bit more delayed due to
anticipated slight veering of steering winds from the S which will
slow the westward thrust. IFR VSBYs also exist, but deeper into
the cloud shield in western KY and far southern IL and still some
doubt as to how low VSBYs will go in STL metro and UIN later
tonight. For now, went on the conservative, optimistic side but
still a shift from previous TAF set. These clouds will prevail
until low level steering winds develop a westerly component to
them Wednesday morning and should see improvement to them into
MVFR.
A low level jet of 45-50kts will develop later this evening
initially into COU-UIN and expand into STL metro overnight and
with the strong inversion in place, will result in LLWS and have
placed in TAFs.
Showers and a few TSRA will rapidly expand into the area towards
daybreak initially into UIN and COU and then somewhat later into
STL metro. For now have handled with SHRA but may have to add TS
later. This should last for 3-4 hours.
A new round of SHRA/TSRA will try to develop later in the
afternoon Wednesday but relatively high uncertainty on how and
when, and with enough other issues to deal with in the short-term
have left this dry.
TES
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
National Weather Service Kansas City/Pleasant Hill MO
936 PM CST TUE DEC 22 2015
.UPDATE...
Issued at 935 PM CST TUE DEC 22 2015
Have made some adjustments to the overnight as well as Wednesday`s
PoPs. This will be most noticeable over the west central and northern
CWA. Satellite imagery shows a shortwave trough lifting northeast
from the eastern TX Panhandle/northwest TX area with a vorticity max
near CDS. Expect scattered elevated showers to form ahead of this
feature after 06z once a narrow tongue of h8 moisture is lifted into
the region via isentropic ascent on the 295K surface. Have followed
the HRRR trend of the past 3-4 runs which is supported quite well by
the 00z NAM as well as the 18z runs of the NAM and GFS. Think we`ll
see showers break out across northwest MO first with a southward
development into the KC area. Will probably see some scattered
elevated showers also pop up well downstream across northeast MO.
Using the above models as a guide believe the deeper moisture
represented by the h7 condensation pressure deficits will be swept
northeast rather quickly and by 15zish Wednesday the more widespread
showers will have lifted out of west central and north central MO.
The deformation band of more stratiform rain now looks like it will
linger over northwest MO well into the afternoon hours.
Have also adjusted overnight temperatures to reflect a steady as she
goes to a slight upward drift.....at least until the rain forms.
&&
.DISCUSSION...
Issued at 345 PM CST TUE DEC 22 2015
Big picture today shows the Nation dominated by a large trough who`s
axis resides across the Western Plains. The local result is a
southwest flow across the Lower Missouri River Valley which has
helped keep the cooler winter air out of our section of the Central
Plains. So, despite that fact that it was cloudy and cold this
morning, along with it being late December, we have warmed into the
40s and 50s again across the region with the help of the southeast
surface wind. Tonight, a shortwave trough, swinging through the base
of the mean longwave trough, will lift across the Central and
Northern Plains late tonight and Wednesday. Resulting warm air
advection ahead of the shortwave will kick in late tonight and
persist through much of Wednesday morning. Currently, models
advertise the rain to move to our northeast by noon Wednesday, but
showers and isolated thunderstorms may linger into the afternoon,
especially as you look farther east across Missouri. None of tonight
or Wednesday weather is expected to be severe, and rainfall totals
Wednesday are only expected to be around a few tenths at most.
For Thursday into Christmas Day...locally, across far eastern Kansas
and the northern half of Missouri, we expect it to be dry, but there
is a none-zero chance that a little precipitation might occur.
Thursday a secondary shortwave trough will follow the larger
Wednesday shortwave trough northeast across the Plains. Most models
have been keen to focus on this quick secondary shortwaves potential
to squeeze some light precipitation out. Have kept slight chance
POPs in across far northern reaches of the forecast area through
Wednesday night into Thursday; and depending on temperatures at that
time, some snow might develop. And, for Christmas Day, while it
could be overcast day, currently it looks like the daylight hours
will be dry locally, but we will be watching for rain to spread
north from southern Missouri that night, with rain persisting
through the weekend.
The weather Christmas Night, and through the weekend, is going to be
a bit of mess. Thursday and Friday we don`t have much chance of
getting wet as we are between storm inducing shortwave troughs, but
by Friday a large amplification in the flow is expected as a strong
shortwave trough digs deep into the mean CONUS trough across the
western CONUS, eventually developing a closed low over the Desert
Southwest which will slowly amble northeast across the Plains late
this weekend into next work week. ECMWF and GFS solutions have all
been pointing at this, though specifics on where the low goes and
how quickly it gets there have been all over the place, with the
ECMWF slowing and then speeding the low up significantly over the
past two model runs. For early in the event, Christmas Night into
Saturday, we will be well ahead of the closed low which will help
keep our temperatures benign for late December with high in the 40s
and 50s still possible Saturday. This means any precipitation early
on will be all liquid for our area. And, the amount of QPF the
models are spitting out indicates that a lot of rain will fall.
Currently, storm totals from Friday night through Monday night in
central Missouri are in the 4 to 6 inch range, tapering to between 1
and 2 inches in the far northwest corner of Missouri. As a result,
anticipate river and stream flooding will be an issue over the
weekend and into next week.
Otherwise, there will be an issue with precipitation type late in
the weekend and early next work week as the low ejects northeast
across the Plains. However, this far out in time, models are having
the typically hard time settling on a solution with the medium
range operational and ensemble models showing a fair amount of
spread in the solutions. So, with out any cold air in place across
our section of the country confidence in precipitation types late in
the weekend and next work week are very low, but have included some
snow and rain snow mix in parts of the Sunday through Monday night
periods.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday Evening)
Issued at 523 PM CST TUE DEC 22 2015
VFR conditions will prevail through the evening hours with increased
winds out of the southeast. Precipitation will begin to develop
overnight, with perhaps some isolated thunder. During this time,
ceilings will reduce to MVFR with diminishing conditions coming into
picture by early Wednesday morning. A shift in mid-level winds out of
the southwest will help to taper off precipitation, though low-level
moisture will bring ceilings down to IFR around 12Z. These are
expected to persist until the early afternoon as winds increase and
shift out of the northwest. Some lingering precipitation could enter
the terminal sites on the back side of the surface low, though this
should only impact KSTJ at the time.
&&
.EAX Watches/Warnings/Advisories...
KS...NONE.
MO...NONE.
&&
$$
UPDATE...MJ
DISCUSSION...Cutter
AVIATION...Welsh
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
120 PM CST MON DEC 21 2015
.SHORT TERM: (Through Tuesday Afternoon)
Issued at 120 PM CST Mon Dec 21 2015
The cold front is making steady progress east across the area
with falling temperatures and a wind shift to the west-northwest.
Dry slot and breaks in the overcast allowed St. Louis to top out
at 67 degrees late this morning which tied the record for the
date that was set back in 1967. What a way to start astronomical
winter, which officially begins at 10:48 PM this evening!
Post frontal IFR stratus deck will blanket the CWA this evening and
despite the subsidence behind the storm system, the low level
moisture will be trapped under the inversion and keep the cloud deck
around tonight or allow for dense fog to develop if there is
clearing. HRRR has been very reliable in these post frontal cloud
forecasts as of late and it shows a LIFR cloud deck through at least
14Z on Tuesday.
Believe clouds or fog will try to scatter/dissipate from
southwest to northeast on Tuesday as flow becomes southerly. Have
forecast temperatures a bit cooler for Tuesday across the
northeastern half of the CWA due to this expected cloud cover.
CVKING
.LONG TERM: (Tuesday Night through Next Monday)
Issued at 120 PM CST Mon Dec 21 2015
Active weather pattern sets up Tuesday night through the
remainder of the forecast. Next shortwave and attendant surface
low/cold front is expected to approach the area from the west
Tuesday night and move across the CWA by late Wednesday evening.
Moisture advection is forecast to increase Tuesday night as the
low level jet increases and showers should be on the increase
after midnight. Can`t rule out a few rumbles of thunder as well,
given MUCAPES around 500 J/KG. This first round of "warm
advection precipitation" should move northeast by late morning on
Wednesday and depending on the amount of clearing and
destablization that can take place across the eastern half of the
CWA, severe thunderstorms may develop ahead and along the cold
front. As with almost any cold season event, the shear and
helicity values are extremely favorable for organized convection.
The question will be the surface based instabilty. The NAM is the
most bullish with around 500-750 J/KG. SPC has placed the eastern
portion of the CWA in a Marginal Risk for Day 3, and historical
analogs (St. Louis University CIPS) certainly support this. Have
introduced severe wording in the HWO and Situational Report to
account for this potential.
Needless to say temperatures will be well above average Tuesday
night and Wednesday. Some of the guidance actually has 70s on
Wednesday afternoon. I would think that is a tad too high, but we
got up to 67 degrees today so I suppose anything is possible this
winter!
The storms, if they develop, should exit rapidly to the east
Wednesday night leaving Christmas Eve and much of Christmas Day dry
and cooler (but yes, still above normal).
Attention then turns to a prolonged rain event Christmas night
through the Holiday Weekend with the prospect of flooding. The
synoptic setup is that the front that drifted to our south moves
back north and sits just to the south of us for a few days with a
classic setup for elevated convection as a deep trof and surface low
develop to our southwest. The front lifts north by early next week
with the system moving over the top of us. GFS has a maximum of
7-10 inches of rain from southwest Missouri through the St. Louis
Metro, the ECWMF has 4-6 inches, and the Central Region SuperBlend
of model data (which includes WPC) has widespread amounts of 5-7
inches. This amount of rain, even spread out over several days,
will cause local streams, creeks and rivers to flood. If
convection occurs and locally higher amounts are realized, then
flash flooding could be a possibility toward the end of the event
once the ground has been thoroughly saturated. Given these
concerns have decided to add mention of flooding in both the HWO
and Situation Report.
Temperatures will remain above normal and fluctuate depending on the
exact placement of the front during the extended portion of the
forecast.
CVKING
&&
.AVIATION: (For the 18z TAFs through 18z Tuesday Afternoon)
Issued at 1139 AM CST Mon Dec 21 2015
Wind gusts drop off with frontal passage and ceilings fall to
MVFR. After frontal passage winds shift to the west and northwest
with ceilings dropping to IFR around midnight. Leaning toward low
clouds opposed to fog for early morning based on model guidance.
Winds shift to the south east by mid morning.
Specifics for KSTL:
Gusty winds from the southeast with scattered clouds ahead of the
frontal passage this afternoon. Wind shifts to the west and sky
becomes overcast with the passage between 20z and 22z. IFR
conditions are expected around midnight. There is a possibility
for fog but guidance as of now leans more toward a low ceiling
instead. Later shifts may need to adjust between fog and stratus.
Walsh/Kanofsky
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED
NWS BILLINGS MT
942 AM MST MON DEC 21 2015
.UPDATE...
WITH THE WARMING BEHIND THE SHORTWAVE LAST NIGHT...TEMPERATURES
DID NOT DROP AS LOW AS HAD BEEN EXPECTED...SO RAISED HIGHS THIS
AFTERNOON A COUPLE OF DEGREES. ANY CHANCE THIS MORNING FOR FOG
HAS DIMINISHED...AND HAS BEEN REMOVED FROM THE FORECAST. REIMER
&&
.SHORT TERM...VALID FOR TDY AND TUE...
A FAST PROGRESSIVE PATTERN CONTINUES THROUGH THE SHORT-TERM
PERIOD. DUE TO THE NATURE OF THE FAST-MOVING WAVES...MODELS ARE
SHOWING DIFFERENCES IN THE HANDLING OF VARIOUS PATTERN FEATURES.
THE FIRST IN A SERIES OF SHORTWAVES WAS CROSSING THE AREA EARLY
THIS MORNING AND WAS SEEN IN WATER VAPOR IMAGERY. THIS WAVE HAD
WEAK PRESSURE FALLS AHEAD OF IT AND WEAK RISES BEHIND IT...AND HAS
CHANGED THE ORIENTATION OF THE SURFACE PRESSURE GRADIENT OVER THE
GAP FLOW AREAS TO A MORE SSW TO ENE GRADIENT. AS A RESULT OF THIS
CHANGE...THE WINDS IN KLVM AND NYE HAVE DECREASED. VISIBILITIES IN
BLOWING SNOW HAVE ALSO COME UP IN KLVM. THE GRADIENT WILL BEGIN TO
FLATTEN OUT AGAIN AROUND 18Z AHEAD OF THE NEXT WAVE...BUT WINDS
ALOFT WILL NOT BE THAT STRONG. THUS WILL CANCEL THE WIND ADVISORY
WITH THIS PACKAGE. WINDS ALOFT DO INCREASE LATE IN THE
AFTERNOON...AND IT/S NOT VERY UNSTABLE...BUT THE PRESSURE GRADIENT
DID NOT SUPPORT GOOD GAP FLOW WITH A SURFACE LOW APPROACHING FROM
THE PACIFIC NW.
REGARDING MORNING FOG...THE EASTWARD MOVING WAVE WILL CONTINUE TO
INCREASE TEMPERATURE/DEWPOINT SPREADS SO ANY FOG WILL BE SHORT-
LIVED AFTER 12Z. THE RAP SUPPORTED THIS SCENARIO AS WELL. SO HAVE
AREAS OF FOG OVER THE SE AND KSHR AREA BASED ON WEB CAMS AND
CURRENT SPREADS...BUT DO NOT ANTICIPATE THE NEED FOR A DENSE FOG
ADVISORY. SOME LIGHT SNOW OR BLOWING SNOW WAS OCCURRING ON THE
COOKE CITY WEB CAM THIS MORNING...OTHERWISE NOT SEEING ANY SNOW
OVER THE AREA AT THIS TIME. CHANCES FOR SNOW WILL INCREASE OVER
AND NEAR THE WESTERN MOUNTAINS...AS WELL AS THE NE BIG HORNS
TODAY AS THE SECOND WAVE APPROACHES...ACCOMPANIED BY ISENTROPIC
LIFT/WARM ADVECTION. DID NOT SEE MUCH ACCUMULATION BASED ON LIGHT
QPF AND TIME-HEIGHTS. THE WAVE AND ACCOMPANYING SURFACE LOW MOVE
ACROSS MT TONIGHT AND MODELS WERE NOT IN GOOD AGREEMENT ON LOW
PLACEMENT AND QPF. BEST SNOW CHANCES WILL BE OVER THE WESTERN
MOUNTAINS. GOOD LIFT AND DECENT DENDRITIC GROWTH SUPPORTED SEVERAL
INCHES OF SNOW THERE. BLENDED GOING POPS WITH CONSALL DUE TO THE
ABOVE UNCERTAINTY. PRESSURE GRADIENT BECOMES MORE FAVORABLE FOR
GAP FLOW LATE TONIGHT...HOWEVER GFS SOUNDINGS WERE VERY UNSTABLE
WHICH WILL WORK AGAINST STRONG GAP FLOW. THUS WILL KEEP WINDS
UNDER ADVISORY CRITERIA.
THE SHORTWAVE PUSHES INTO THE DAKOTAS TUE MORNING AND WEAK ENERGY
FOLLOWS THE WAVE. MODELS CONTINUED THEIR DISAGREEMENTS WITH QPF
PLACEMENT...SO BLENDED POPS WITH CONSALL...RESULTING IN HIGHEST
POPS OVER WESTERN MOUNTAINS. AIRMASS SHOULD DRY OUT LATE TUE
NIGHT. ARTHUR
.LONG TERM...VALID FOR WED...THU...FRI...SAT...SUN...
EXTENDED PERIOD BEGINS WITH A TROUGH AXIS THROUGH CENTRAL
MONTANA. THE FLOW ALOFT WILL MOSTLY BE ZONAL WITH A SERIES OF WEAK
DISTURBANCES PASSING THROUGH CENTRAL MONTANA. THESE WAVES WILL
BRING WITH THEM LIKELY SNOW SHOWERS TO HIGHER TERRAIN AND WESTERN
LOCATIONS. THESE WILL IMPACT LOCATIONS IN AND WEST OF THE DIVIDE
NEAR LIVINGSTON AND COOKE CITY. A FEW OF THESE SNOW SHOWERS COULD
MAKE IT PAST THE DIVIDE BUT AM NOT EXPECTING IMPACTFUL...IF
ANY...ACCUMULATIONS THROUGH CHRISTMAS DAY.
BIGGER CHANGE IN THE WEATHER TAKES SHAPE CHRISTMAS-EVE AFTERNOON
AS PACIFIC TROUGH BEGINS TO AMPLIFY ALONG THE WESTERN US. AS THIS
FEATURE DIGS SOUTH...SFC HIGH PRESSURE SLIDES IN FROM THE
NORTHEAST AND USHERS IN MUCH COOLER AIR CHRISTMAS EVE AND
CHRISTMAS DAY. MORNING LOWS SHOULD BOTTOM OUT IN THE SINGLE DIGITS
FOR MOST LOCATIONS WITH HIGH TEMPERATURES IN THE TEENS. MOST
LOCATIONS APPEAR DRY FOR NOW BUT EXTREME SOUTHERN PARTS OF MONTANA
COULD SEE AN ISOLATED SNOW SHOWER CHRISTMAS AND EARLY SATURDAY AS
THE PACIFIC TROUGH CUTS OFF OVER UTAH AND NORTHERN COLORADO.
IN ADDITION TO THE COOLER TEMPERATURES CHRISTMAS DAY...THE
BIGGEST CONCERN REVOLVES AROUND A PERIOD OF STRONG GAP WINDS
AROUND LIVINGSTON AND BIG TIMBER. RIDGE AXIS MOVING BEHIND THE CUT
OFF LOW TO OUR SOUTH SHOULD ALLOW GOOD RADIATIONAL COOLING
CONDITIONS AND PRESSURE GRADIENTS APPEAR VERY FAVORABLE FOR TWO
PERIODS OF ELEVATED WINDS. STRENGTHENING FLOW OVER NORTHWEST
MONTANA WILL ALSO HELP INDUCE LEE-SIDE TROUGHING SATURDAY
AFTERNOON. THE FIRST EVENT WILL AFFECT LIVINGSTON SATURDAY NIGHT
AND SUNDAY MORNING...AND THE SECOND WILL BE BIG TIMBER AND
HARLOWTON AS THE GRADIENT BECOMES MORE WESTERLY SUNDAY MORNING AND
AFTERNOON. DOBBS
&&
.AVIATION...
VFR FLIGHT CONDITIONS WILL PREVAIL ACROSS THE LOWER ELEVATIONS
TODAY. A PACIFIC DISTURBANCE WILL BRING SNOW TO THE BEARTOOTH...
ABSAROKA AND CRAZY MOUNTAINS ALONG WITH FREQUENT OBSERVATIONS THIS
AFTERNOON AND TONIGHT. LOCAL MVFR IS POSSIBLE NEAR KMLS TONIGHT
BUT VFR SHOULD PERSIST ELSEWHERE. EXPECT SW WIND GUSTS OF 30-40
KTS AT KLVM. JKL
&&
.PRELIMINARY POINT TEMP/POPS...
TDY TUE WED THU FRI SAT SUN
-------------------------------------------------------
BIL 036 025/035 015/028 014/025 005/017 003/023 014/037
1/B 22/J 21/E 11/E 11/E 11/U 11/N
LVM 035 027/033 014/026 015/025 001/021 003/023 012/034
2/J 33/J 22/J 22/J 22/J 11/N 11/N
HDN 039 022/037 009/028 014/027 004/017 901/022 006/034
1/B 23/J 21/E 11/E 11/E 11/U 11/B
MLS 036 021/033 011/025 011/023 005/017 901/019 009/029
1/U 22/J 31/B 11/B 11/E 11/U 11/U
4BQ 038 022/036 012/029 012/027 008/020 003/021 008/030
1/B 12/J 21/B 11/B 11/E 21/U 11/U
BHK 037 021/034 015/026 011/024 006/017 001/020 007/031
1/B 12/J 32/J 11/B 11/E 11/B 11/B
SHR 036 021/036 007/028 010/025 002/019 901/024 007/034
1/B 12/J 22/J 11/B 12/J 21/U 11/B
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS BILLINGS MT
323 AM MST MON DEC 21 2015
.SHORT TERM...VALID FOR TDY AND TUE...
A FAST PROGRESSIVE PATTERN CONTINUES THROUGH THE SHORT-TERM
PERIOD. DUE TO THE NATURE OF THE FAST-MOVING WAVES...MODELS ARE
SHOWING DIFFERENCES IN THE HANDLING OF VARIOUS PATTERN FEATURES.
THE FIRST IN A SERIES OF SHORTWAVES WAS CROSSING THE AREA EARLY
THIS MORNING AND WAS SEEN IN WATER VAPOR IMAGERY. THIS WAVE HAD
WEAK PRESSURE FALLS AHEAD OF IT AND WEAK RISES BEHIND IT...AND HAS
CHANGED THE ORIENTATION OF THE SURFACE PRESSURE GRADIENT OVER THE
GAP FLOW AREAS TO A MORE SSW TO ENE GRADIENT. AS A RESULT OF THIS
CHANGE...THE WINDS IN KLVM AND NYE HAVE DECREASED. VISIBILITIES IN
BLOWING SNOW HAVE ALSO COME UP IN KLVM. THE GRADIENT WILL BEGIN TO
FLATTEN OUT AGAIN AROUND 18Z AHEAD OF THE NEXT WAVE...BUT WINDS
ALOFT WILL NOT BE THAT STRONG. THUS WILL CANCEL THE WIND ADVISORY
WITH THIS PACKAGE. WINDS ALOFT DO INCREASE LATE IN THE
AFTERNOON...AND IT/S NOT VERY UNSTABLE...BUT THE PRESSURE GRADIENT
DID NOT SUPPORT GOOD GAP FLOW WITH A SURFACE LOW APPROACHING FROM
THE PACIFIC NW.
REGARDING MORNING FOG...THE EASTWARD MOVING WAVE WILL CONTINUE TO
INCREASE TEMPERATURE/DEWPOINT SPREADS SO ANY FOG WILL BE SHORT-
LIVED AFTER 12Z. THE RAP SUPPORTED THIS SCENARIO AS WELL. SO HAVE
AREAS OF FOG OVER THE SE AND KSHR AREA BASED ON WEB CAMS AND
CURRENT SPREADS...BUT DO NOT ANTICIPATE THE NEED FOR A DENSE FOG
ADVISORY. SOME LIGHT SNOW OR BLOWING SNOW WAS OCCURRING ON THE
COOKE CITY WEB CAM THIS MORNING...OTHERWISE NOT SEEING ANY SNOW
OVER THE AREA AT THIS TIME. CHANCES FOR SNOW WILL INCREASE OVER
AND NEAR THE WESTERN MOUNTAINS...AS WELL AS THE NE BIG HORNS
TODAY AS THE SECOND WAVE APPROACHES...ACCOMPANIED BY ISENTROPIC
LIFT/WARM ADVECTION. DID NOT SEE MUCH ACCUMULATION BASED ON LIGHT
QPF AND TIME-HEIGHTS. THE WAVE AND ACCOMPANYING SURFACE LOW MOVE
ACROSS MT TONIGHT AND MODELS WERE NOT IN GOOD AGREEMENT ON LOW
PLACEMENT AND QPF. BEST SNOW CHANCES WILL BE OVER THE WESTERN
MOUNTAINS. GOOD LIFT AND DECENT DENDRITIC GROWTH SUPPORTED SEVERAL
INCHES OF SNOW THERE. BLENDED GOING POPS WITH CONSALL DUE TO THE
ABOVE UNCERTAINTY. PRESSURE GRADIENT BECOMES MORE FAVORABLE FOR
GAP FLOW LATE TONIGHT...HOWEVER GFS SOUNDINGS WERE VERY UNSTABLE
WHICH WILL WORK AGAINST STRONG GAP FLOW. THUS WILL KEEP WINDS
UNDER ADVISORY CRITERIA.
THE SHORTWAVE PUSHES INTO THE DAKOTAS TUE MORNING AND WEAK ENERGY
FOLLOWS THE WAVE. MODELS CONTINUED THEIR DISAGREEMENTS WITH QPF
PLACEMENT...SO BLENDED POPS WITH CONSALL...RESULTING IN HIGHEST
POPS OVER WESTERN MOUNTAINS. AIRMASS SHOULD DRY OUT LATE TUE
NIGHT. ARTHUR
.LONG TERM...VALID FOR WED...THU...FRI...SAT...SUN...
EXTENDED PERIOD BEGINS WITH A TROUGH AXIS THROUGH CENTRAL
MONTANA. THE FLOW ALOFT WILL MOSTLY BE ZONAL WITH A SERIES OF WEAK
DISTURBANCES PASSING THROUGH CENTRAL MONTANA. THESE WAVES WILL
BRING WITH THEM LIKELY SNOW SHOWERS TO HIGHER TERRAIN AND WESTERN
LOCATIONS. THESE WILL IMPACT LOCATIONS IN AND WEST OF THE DIVIDE
NEAR LIVINGSTON AND COOKE CITY. A FEW OF THESE SNOW SHOWERS COULD
MAKE IT PAST THE DIVIDE BUT AM NOT EXPECTING IMPACTFUL...IF
ANY...ACCUMULATIONS THROUGH CHRISTMAS DAY.
BIGGER CHANGE IN THE WEATHER TAKES SHAPE CHRISTMAS-EVE AFTERNOON
AS PACIFIC TROUGH BEGINS TO AMPLIFY ALONG THE WESTERN US. AS THIS
FEATURE DIGS SOUTH...SFC HIGH PRESSURE SLIDES IN FROM THE
NORTHEAST AND USHERS IN MUCH COOLER AIR CHRISTMAS EVE AND
CHRISTMAS DAY. MORNING LOWS SHOULD BOTTOM OUT IN THE SINGLE DIGITS
FOR MOST LOCATIONS WITH HIGH TEMPERATURES IN THE TEENS. MOST
LOCATIONS APPEAR DRY FOR NOW BUT EXTREME SOUTHERN PARTS OF MONTANA
COULD SEE AN ISOLATED SNOW SHOWER CHRISTMAS AND EARLY SATURDAY AS
THE PACIFIC TROUGH CUTS OFF OVER UTAH AND NORTHERN COLORADO.
IN ADDITION TO THE COOLER TEMPERATURES CHRISTMAS DAY...THE
BIGGEST CONCERN REVOLVES AROUND A PERIOD OF STRONG GAP WINDS
AROUND LIVINGSTON AND BIG TIMBER. RIDGE AXIS MOVING BEHIND THE CUT
OFF LOW TO OUR SOUTH SHOULD ALLOW GOOD RADIATIONAL COOLING
CONDITIONS AND PRESSURE GRADIENTS APPEAR VERY FAVORABLE FOR TWO
PERIODS OF ELEVATED WINDS. STRENGTHENING FLOW OVER NORTHWEST
MONTANA WILL ALSO HELP INDUCE LEE-SIDE TROUGHING SATURDAY
AFTERNOON. THE FIRST EVENT WILL AFFECT LIVINGSTON SATURDAY NIGHT
AND SUNDAY MORNING...AND THE SECOND WILL BE BIG TIMBER AND
HARLOWTON AS THE GRADIENT BECOMES MORE WESTERLY SUNDAY MORNING AND
AFTERNOON. DOBBS
&&
.AVIATION...
VFR CONDITIONS SHOULD PREVAIL AT ALL TAF SITES THROUGH THE
PERIOD. THOUGH SOME MVFR/IFR FOG IS POSSIBLE FOR A VERY BRIEF
PERIOD NEAR SUNRISE AT KMLS AND KSHR. UPPER LEVEL DISTURBANCE
PUSHING EAST IS WORKING AGAINST THIS THOUGH SO AM NOT CONFIDENT
FLIGHT RULES DROP BELOW VFR. VCSH POSSIBLE AT KLVM LATE THIS
MORNING THROUGH THE AFTERNOON. MOUNTAIN OBSCURATIONS CAN BE
EXPECTED IN THE HEAVIER SHOWERS. DOBBS
&&
.PRELIMINARY POINT TEMP/POPS...
TDY TUE WED THU FRI SAT SUN
-------------------------------------------------------
BIL 035 025/035 015/028 014/025 005/017 003/023 014/037
1/B 22/J 21/E 11/E 11/E 11/U 11/N
LVM 035 027/033 014/026 015/025 001/021 003/023 012/034
2/J 33/J 22/J 22/J 22/J 11/N 11/N
HDN 038 022/037 009/028 014/027 004/017 901/022 006/034
1/B 23/J 21/E 11/E 11/E 11/U 11/B
MLS 037 021/033 011/025 011/023 005/017 901/019 009/029
1/B 22/J 31/B 11/B 11/E 11/U 11/U
4BQ 037 022/036 012/029 012/027 008/020 003/021 008/030
1/B 12/J 21/B 11/B 11/E 21/U 11/U
BHK 037 021/034 015/026 011/024 006/017 001/020 007/031
1/B 12/J 32/J 11/B 11/E 11/B 11/B
SHR 036 021/036 007/028 010/025 002/019 901/024 007/034
1/B 12/J 22/J 11/B 12/J 21/U 11/B
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION...UPDATED
NWS BILLINGS MT
932 PM MST SUN DEC 20 2015
.UPDATE...
TWO FORECAST ISSUES THIS EVENING WHICH ARE DIVIDED BY SURFACE
PRESSURE TROUGH WITH DRIER AIR TO THE WEST WITH MOIST AIR TO THE
EAST. FIRST...FOG DEVELOPING ACROSS MUCH OF EASTERN MONTANA . WE
UPDATED EARLY TO ADD THIS TO FORECAST FROM STILLWATER COUNTY
EASTWARD AND INCLUDING SHERIDAN COUNTY IN WYOMING. THIS IS ALL
EAST OF THE SURFACE TROUGH. I DO NOT ANTICIPATE BEING AS
WIDESPREAD DENSE LIKE IT WAS SUNDAY MORNING...SO HAVE HELD OFF ON
ADVISORY FOR NOW. CLOUDS MOVING OVER REGION FROM WEST MAY CAUSE
FOG TO LIFT AND DISSIPATE IN SOME AREAS LATE.
WEST OF SURFACE TROUGH PRESSURE GRADIENT HAS INCREASED AND IS
PRODUCING STRONG SOUTHWEST WINDS IN GAP AREAS AROUND LIVINGSTON
AND NYE. MOS GUIDANCE NOT HANDLING THIS WELL AS HAS BEEN THE CASE
LATELY...BUT HRRR MODEL SOUNDINGS DEFINEATELY SHOW STRONG WINDS
WITHIN BOUNDARY LAYER. NEXT SHIFT MAY NEED TO ISSUE ADVISORY...BUT
LIVINGSTON WINDS CURRENTLY REMAINING SAFELY BELOW OUR ADVISORY
CRITERIA. THE WINDS HAVE CREATED SOME BLOWING SNOW AGAIN...BUT
SEEMS LIMITED TO BETWEEN 1 AND 3 MILES AND NOT AS BAD AS LAST
THURSDAY NIGHT...PROBABLY DUE TO SOME ABOVE FREEZING TEMPS THIS
WEEKEND. AT ANY RATE...HAVE INCREASED WINDS AND INCLUDED BLOWING
SNOW IN FORECAST FOR THESE AREAS OVERNIGHT. ISSUED WIND ADVISORY
THROUGH JUST 9 AM BASED ON LULL TOMORROW IN NAM DATA...BUT
SUSPECT WE COULD SEE THESE WINDS AGAIN TOMORROW NIGHT. BT
&&
.SHORT TERM...VALID FOR MON AND TUE...
THE TRAIN OF SHORTWAVES CONTINUES THROUGH THE SHORT TERM...WITH
FLOW REMAINING PROGRESSIVE THROUGH THE PERIOD. GIVEN THIS
PROGRESSIVE PATTERN...THESE SYSTEMS WILL FOR THE MOST PART BE
LACKING IN DYNAMIC...THUS NOT EXPECTING ANY SIGNIFICANT
ACCUMULATIONS.
THE FIRST WAVE MOVES THROUGH OVERNIGHT...HOWEVER THE BULK OF THE
ENERGY MOVES NORTH OF THE AREA RESULTING IN MUCH OF THE AREA
REMAINING DRY. THERE IS STILL SOME INSTABILITY...MAINLY AROUND
THE SOUTHWESTERN MOUNTAINS AND FOOTHILLS...SO A LITTLE BIT OF
ACCUMULATING SNOWFALL CAN BE EXPECTED IN THE HIGHER TERRAIN. FOR
THE REMAINDER OF THE AREA...THERE COULD BE SOME PATCHY FOG BUT AT
THIS POINT GIVEN WINDS WILL BE STRONGER HAVE NOT MENTIONED
ANYTHING IN THE GRIDS.
MONDAY NIGHT THE NEXT WAVE WILL MOVE THROUGH AND BRING A SLIGHTLY
BETTER CHANCE FOR SNOWFALL. THE ENERGY WITH THIS SYSTEM WILL PUSH
FARTHER SOUTH...WHICH WILL SPREAD THE SNOW CHANCES OUT ON TO THE
PLAINS. THE INSTABILITY WILL BE BETTER WITH THIS SYSTEM...SO COULD
SEE SOME BETTER ACCUMULATIONS...BUT WILL STILL REMAIN UNDER ANY
CRITERIA.
TEMPERATURES WILL REMAIN FAIRLY SEASONAL THROUGH THE PERIOD.
REIMER
.LONG TERM...VALID FOR WED...THU...FRI...SAT...SUN...
EXTENDED MODELS WERE IN OVERALL AGREEMENT THROUGH THE PERIOD IN
SHOWING WESTERLY FLOW WITH MULTIPLE SHORTWAVES... AS PER EURO AND
GFS GUIDANCE. PRECIP CHANCES LOOK TO BE MOSTLY LIMITED TO WESTERN
TERRAIN ON WED AND THUR WITH SLIGHT CHANGES IN THE EASTERN PLAINS
ON WED. MODELS CONTINUE TO BRING A DEEPER TROUGH INTO THE REGION
ON FRI... BRINGING THE MOST WIDESPREAD CHANCES OF SLIGHT POPS
BETWEEN THE MORNING AND AFTERNOON HOURS OF XMAS DAY. PRECIP
CHANCES WILL THEN DIMINISH IN SE MT AS THE POSITIVELY TILTED
TROUGH EXITS LATER THAT DAY. UPPER-LEVEL FLOW LOOKS TO THEN RETURN
TO RIDGING BEHIND THIS TROUGH... WITH A MUCH DRIER PATTERN ACROSS
THE CWA.
SFC PRESSURE GRADIENT SETS UP QUITE STRONGLY OVER THE WESTERN
FOOTHILLS OVERNIGHT SAT AND CONTINUES THRU SUN WITH SOME
DIFFERENCES BETWEEN THE MODELS ON HOW THE GRADIENT SETS UP. BASED
ON THE CONTINUED GRADIENT STRENGTH...HAVE RETAINED GAP FLOW WINDS
WITHIN THE ADVISORY/WARNING CRITERIA DURING THIS TIME FRAME. WILL
DEFINITELY NEED TO WATCH MODEL TRENDS TO SEE IF THIS PATTERN
CONTINUES TO PERSIST FROM RUN-TO-RUN.
NEAR-NORMAL TEMPERATURES WILL CONTINUE EARLY IN THE PERIOD. THUR
AND FRI WILL BE THE COLDEST DAYS WITH MAXT VALUES IN THE MID TO
LOW 20S...THEN TEMPERATURES WILL MODERATE THROUGH THE WEEKEND...
PERHAPS INTO THE MID 30S ON SUN. MROWELL
&&
.AVIATION...
SOME AREAS OF FOG EXPECTED TONIGHT ACROSS SOUTHERN MONTANA AND
NORTH-CENTRAL WYOMING. A FEW SNOW SHOWERS ARE POSSIBLE WEST OF
KBIL OVERNIGHT AND MON AFTERNOON-EVENING. CONDITIONS CAN DROP TO
MVFR/IFR IN SNOW SHOWERS AND VLIFR IN FOG. OTHERWISE...CONDITIONS
WILL BE VFR. MOUNTAIN OBSCURATIONS LIKELY TONIGHT AND MONDAY.
LLWS IS POSSIBLE NEAR KBIL...KMLS AND KSHR TONIGHT INTO MON
MORNING. RMS/BT
&&
.PRELIMINARY POINT TEMP/POPS...
MON TUE WED THU FRI SAT SUN
-----------------------------------------------------------
BIL 021/034 023/035 018/029 013/024 008/020 007/024 015/036
11/B 23/J 22/J 11/E 12/J 11/N 11/N
LVM 021/033 024/034 018/027 014/025 008/020 006/020 012/032
33/S 45/J 42/J 22/J 22/J 21/N 11/N
HDN 017/037 019/037 012/032 007/026 002/020 001/024 002/035
11/B 23/J 22/J 11/E 12/J 21/U 11/B
MLS 021/036 017/033 013/029 012/023 004/019 003/023 009/035
11/B 13/J 22/J 11/E 12/J 11/U 11/B
4BQ 020/036 018/036 014/029 009/026 007/022 002/023 010/035
01/B 12/J 22/J 11/E 12/J 21/B 11/B
BHK 020/035 017/033 014/029 013/025 005/020 005/023 009/036
11/B 03/J 31/B 11/B 11/E 21/B 11/B
SHR 017/036 018/036 013/028 006/026 003/022 000/023 008/037
12/S 23/J 22/J 11/B 12/J 21/U 11/B
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...WIND ADVISORY IN EFFECT UNTIL 8 AM MST MONDAY FOR ZONES
65-66.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1145 AM CST MON DEC 21 2015
.SYNOPSIS...
ISSUED AT 340 AM CST MON DEC 21 2015
H5 ANALYSIS FROM EARLIER THIS EVENING HAD A LOW AMPLITUDE PATTERN
ACROSS THE CONUS. ZONAL FLOW WAS PRESENT FROM THE WEST COAST...EWD
TO THE MISSISSIPPI RIVER. EAST OF THE RIVER...LOW AMPLITUDE
RIDGING WAS PRESENT FROM SOUTH CAROLINA...NWD INTO SRN QUEBEC.
ACROSS THE CENTRAL AND SRN PLAINS...A DECENT SHORTWAVE TROUGH WAS
NOTED OVER SERN COLORADO. CURRENTLY...THIS FEATURE WAS LOCATED
OVER CENTRAL KS. AT THE SURFACE...A COLD FRONT HAS PASSED WELL
SOUTH OF THE FORECAST AREA THIS EVENING AND WAS ORIENTED ALONG A
LINE FROM DES MOINES IOWA...TO ST JOSEPH MISSOURI...TO WICHITA
KANSAS. ACROSS WESTERN AND NORTH CENTRAL NEBRASKA...A VEIL OF LOW
CLOUDINESS HAS SET IN ACROSS THE FORECAST AREA WITH CIGS GENERALLY
BETWEEN 500 TO 1000 FT AGL OVERNIGHT. SOME FOG WAS PRESENT IN THE
NEBRASKA PANHANDLE...ALONG THE WESTERN FLANK OF THE INVADING
STRATUS. TEMPERATURES WERE FAIRLY MILD FOR MID DECEMBER AS 3 AM
CST READINGS WERE GENERALLY IN THE 20S.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 340 AM CST MON DEC 21 2015
FOG POTENTIAL THIS MORNING...COUPLED WITH CLOUDINESS AND ITS
IMPACTS ON TEMPERATURES WILL BE THE MAIN FORECAST CHALLENGE. FOR
THIS MORNING WITH RESPECT TO FOG POTENTIAL...SUPPORT FOR AT LEAST
A PATCHY FOG MENTION CONTINUES INTO THE MID TO LATE MORNING
HOURS...ESPECIALLY OVER NORTH CENTRAL NEBRASKA PER THE LATEST
NAM12...SREF PROBABILITIES FCST...AS WELL AS THE HRRR SFC VISBY
FORECAST. ALBEIT...THE HRRR IS MOST AGGRESSIVE WITH THE
FOG...CONTINUING IT WELL INTO THE AFTERNOON HOURS ACROSS NORTHERN
AND NORTHEASTERN PORTIONS OF THE FORECAST AREA. THE HRRR DOES NOT
HAVE THE SUPPORT OF THE NAM12 AND SREF FOR EXTENDING FOG PAST
MIDDAY. THIS IS ALSO REFLECTED IN THE STATISTICAL GUIDANCE AS
WELL. THAT BEING SAID...WILL PLAN ON ENDING THE MENTION OF FOG
AFTER 16Z THIS MORNING. AS FOR TEMPERATURES TODAY...LOW LEVEL
CLOUDS SHOULD HANG ON WELL INTO THE AFTERNOON HOURS ACROSS
NORTHERN NEBRASKA PER NAM12 AND SREF H850-H900 LAYER RH
FORECASTS...AND THIS WILL HAVE A HUGE IMPACT ON HIGHS IN THE NORTH
TODAY. FOR THE SRN HALF OF THE FORECAST AREA...LOW CLOUDS SHOULD
BURN OFF BY MIDDAY...ALLOWING TEMPS TO REACH INTO THE 40S. FOR
TONIGHT...A SURFACE TROUGH WILL DEEPEN ACROSS EASTERN WYOMING WITH
A TIGHTENING SURFACE PRESSURE GRADIENT DEVELOPING OVERNIGHT. H925
AND H85 WINDS SUPPORT SOME MIXING AFTER MIDNIGHT...AND GUIDANCE
ACTUALLY SUPPORTS TEMPS WARMING IN THE WEST AND NORTHERN CWA
OVERNIGHT WITH LOWS OCCURRING DURING THE EVENING HRS. WITH THE
EXCEPTION OF THE PLATTE RIVER VALLEY WHERE UPPER TEENS ARE
EXPECTED...LOWS WILL GENERALLY BE IN THE MIDDLE 20S AND SHOULD BE
ACHIEVED DURING THE LATE EVENING TO THE EARLY OVERNIGHT HRS.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 340 AM CST MON DEC 21 2015
A COUPLE OF FAST MOVING SHORTWAVE DISTURBANCES WILL CROSS THE AREA
TUESDAY AND WEDNESDAY. AN INCREASE IN MID AND HIGH LEVEL
CLOUDINESS CAN BE EXPECTED DURING THIS TIME. DID ADD A SLIGHT
CHANCE FOR SNOW SHOWERS WEDNESDAY NIGHT. APPEARS TO BE ENOUGH
LIFT AND SATURATION PRESENT TO WARRANT A SLIGHT CHANCE DURING
THIS TIME. OTHERWISE A MILD PACIFIC AIRMASS IN PLACE WITH A
WESTERLY DOWNSLOPE CHINOOK TYPE LOW LEVEL FLOW. DESPITE DOWNSLOPE
FLOW...DID LIMIT DAYTIME HIGHS A BIT TO UPPER 30S AND 40S DUE TO
EXPECTED MID AND HIGH CLOUDS AND LINGERING SNOW COVER IN SPOTS.
MODELS HAVE COME INTO BETTER AGREEMENT TONIGHT FOR THE CHRISTMAS
EVE THROUGH SATURDAY PERIOD. GEM/GFS/ECMWF AND MOST GFS ENSEMBLE
MEMBERS INDICATE THAT A SIGNIFICANT SHORTWAVE WILL DIVE SOUTHEAST
FROM THE GULF OF ALASKA INTO THE DESERT SOUTHWEST BY CHRISTMAS
MORNING. ALL THREE OPERATIONAL MODELS CLOSE THE SYSTEM OFF AND
SLOWLY MOVE IT EASTWARD TOWARD WEST TX BY SUNDAY NIGHT. BROAD
SOUTHWEST FLOW ALOFT WITH EMBEDDED 140 KT JET STREAK WILL
OVERSPREAD THE CENTRAL AND SOUTHERN PLAINS CHRISTMAS DAY THROUGH
SATURDAY NIGHT AHEAD OF THE SYSTEM. LIFT ASSOCIATED WITH THE JET
CIRCULATION AND DECENT LOW/MID LEVEL MOISTURE ADVECTION INTO THE
AREA SHOULD YIELD A PERIOD OF SNOW CHRISTMAS NIGHT THROUGH
SATURDAY. WILL CONTINUE THE CAUTIOUS...CONSERVATIVE APPROACH
REGARDING SNOW CHANCES THIS FORECAST CYCLE...BUT...IF MODELS
CONTINUE TO SHOW TONIGHTS IMPROVED AGREEMENT...CHANCES WILL HAVE
TO BE INCREASED. IN ADDITION...A STRONG COLD FRONT WILL CROSS THE
AREA DURING THE DAY SATURDAY. NORTH WINDS WILL INCREASE BEHIND THE
FRONT...WHICH COULD LEAD TO SOME BLOWING SNOW IF ENOUGH
ACCUMULATES.
BY SUNDAY...THE JET DYNAMICS AND ASSOCIATED LIFT WILL
WEAKEN...AND WITH THE CLOSED UPPER LOW EXPECTED TO BE WELL TO OUR
SOUTH...WILL LEAVE THE FORECAST DRY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1145 AM CST MON DEC 21 2015
THERE IS A CONFLICTING MESSAGE IN THE NEAR TERM SOLUTIONS
CONCERNING THE RETURN OF STRATUS AND/OR FOG AT BOTH KLBF AND KVTN
THIS EVENING AND OVERNIGHT. FOR THIS...FORECAST CONFIDENCE IS
RATHER WEAK. WE DO ANTICIPATE THAT SOUTHWEST TO WESTERLY WINDS
WILL INCREASE OVERNIGHT ACROSS THE PANHANDLE AND CENTRAL SANDHILLS
AS THE SFC PRESSURE GRADIENT INCREASES. THIS WOULD FAVOR STRATUS
RATHER THAN FOG. WILL INCLUDE A SCT015 DECK AT BOTH KVTN AND
KLBF...AND UPDATE AS CONDITIONS WARRANT.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BUTTLER
SHORT TERM...BUTTLER
LONG TERM...TAYLOR
AVIATION...JACOBS
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
555 AM CST MON DEC 21 2015
.SYNOPSIS...
ISSUED AT 340 AM CST MON DEC 21 2015
H5 ANALYSIS FROM EARLIER THIS EVENING HAD A LOW
AMPLITUDE PATTERN ACROSS THE CONUS. ZONAL FLOW WAS PRESENT FROM THE
WEST COAST...EWD TO THE MISSISSIPPI RIVER. EAST OF THE RIVER...LOW
AMPLITUDE RIDGING WAS PRESENT FROM SOUTH CAROLINA...NWD INTO SRN
QUEBEC. ACROSS THE CENTRAL AND SRN PLAINS...A DECENT SHORTWAVE
TROUGH WAS NOTED OVER SERN COLORADO. CURRENTLY...THIS FEATURE WAS
LOCATED OVER CENTRAL KS. AT THE SURFACE...A COLD FRONT HAS PASSED
WELL SOUTH OF THE FORECAST AREA THIS EVENING AND WAS ORIENTED ALONG
A LINE FROM DES MOINES IOWA...TO ST JOSEPH MISSOURI...TO WICHITA
KANSAS. ACROSS WESTERN AND NORTH CENTRAL NEBRASKA...A VEIL OF LOW
CLOUDINESS HAS SET IN ACROSS THE FORECAST AREA WITH CIGS GENERALLY
BETWEEN 500 TO 1000 FT AGL OVERNIGHT. SOME FOG WAS PRESENT IN THE
NEBRASKA PANHANDLE...ALONG THE WESTERN FLANK OF THE INVADING
STRATUS. TEMPERATURES WERE FAIRLY MILD FOR MID DECEMBER AS 3 AM CST
READINGS WERE GENERALLY IN THE 20S.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 340 AM CST MON DEC 21 2015
FOG POTENTIAL THIS MORNING...COUPLED WITH CLOUDINESS AND ITS
IMPACTS ON TEMPERATURES WILL BE THE MAIN FORECAST CHALLENGE. FOR
THIS MORNING WITH RESPECT TO FOG POTENTIAL...SUPPORT FOR AT LEAST
A PATCHY FOG MENTION CONTINUES INTO THE MID TO LATE MORNING
HOURS...ESPECIALLY OVER NORTH CENTRAL NEBRASKA PER THE LATEST
NAM12...SREF PROBABILITIES FCST...AS WELL AS THE HRRR SFC VISBY
FORECAST. ALBEIT...THE HRRR IS MOST AGGRESSIVE WITH THE
FOG...CONTINUING IT WELL INTO THE AFTERNOON HOURS ACROSS NORTHERN
AND NORTHEASTERN PORTIONS OF THE FORECAST AREA. THE HRRR DOES NOT
HAVE THE SUPPORT OF THE NAM12 AND SREF FOR EXTENDING FOG PAST
MIDDAY. THIS IS ALSO REFLECTED IN THE STATISTICAL GUIDANCE AS
WELL. THAT BEING SAID...WILL PLAN ON ENDING THE MENTION OF FOG
AFTER 16Z THIS MORNING. AS FOR TEMPERATURES TODAY...LOW LEVEL
CLOUDS SHOULD HANG ON WELL INTO THE AFTERNOON HOURS ACROSS
NORTHERN NEBRASKA PER NAM12 AND SREF H850-H900 LAYER RH
FORECASTS...AND THIS WILL HAVE A HUGE IMPACT ON HIGHS IN THE NORTH
TODAY. FOR THE SRN HALF OF THE FORECAST AREA...LOW CLOUDS SHOULD
BURN OFF BY MIDDAY...ALLOWING TEMPS TO REACH INTO THE 40S. FOR
TONIGHT...A SURFACE TROUGH WILL DEEPEN ACROSS EASTERN WYOMING WITH
A TIGHTENING SURFACE PRESSURE GRADIENT DEVELOPING OVERNIGHT. H925
AND H85 WINDS SUPPORT SOME MIXING AFTER MIDNIGHT...AND GUIDANCE
ACTUALLY SUPPORTS TEMPS WARMING IN THE WEST AND NORTHERN CWA
OVERNIGHT WITH LOWS OCCURRING DURING THE EVENING HRS. WITH THE
EXCEPTION OF THE PLATTE RIVER VALLEY WHERE UPPER TEENS ARE
EXPECTED...LOWS WILL GENERALLY BE IN THE MIDDLE 20S AND SHOULD BE
ACHIEVED DURING THE LATE EVENING TO THE EARLY OVERNIGHT HRS.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 340 AM CST MON DEC 21 2015
A COUPLE OF FAST MOVING SHORTWAVE DISTURBANCES WILL CROSS THE AREA
TUESDAY AND WEDNESDAY. AN INCREASE IN MID AND HIGH LEVEL
CLOUDINESS CAN BE EXPECTED DURING THIS TIME. DID ADD A SLIGHT
CHANCE FOR SNOW SHOWERS WEDNESDAY NIGHT. APPEARS TO BE ENOUGH
LIFT AND SATURATION PRESENT TO WARRANT A SLIGHT CHANCE DURING
THIS TIME. OTHERWISE A MILD PACIFIC AIRMASS IN PLACE WITH A
WESTERLY DOWNSLOPE CHINOOK TYPE LOW LEVEL FLOW. DESPITE DOWNSLOPE
FLOW...DID LIMIT DAYTIME HIGHS A BIT TO UPPER 30S AND 40S DUE TO
EXPECTED MID AND HIGH CLOUDS AND LINGERING SNOW COVER IN SPOTS.
MODELS HAVE COME INTO BETTER AGREEMENT TONIGHT FOR THE CHRISTMAS
EVE THROUGH SATURDAY PERIOD. GEM/GFS/ECMWF AND MOST GFS ENSEMBLE
MEMBERS INDICATE THAT A SIGNIFICANT SHORTWAVE WILL DIVE SOUTHEAST
FROM THE GULF OF ALASKA INTO THE DESERT SOUTHWEST BY CHRISTMAS
MORNING. ALL THREE OPERATIONAL MODELS CLOSE THE SYSTEM OFF AND
SLOWLY MOVE IT EASTWARD TOWARD WEST TX BY SUNDAY NIGHT. BROAD
SOUTHWEST FLOW ALOFT WITH EMBEDDED 140 KT JET STREAK WILL
OVERSPREAD THE CENTRAL AND SOUTHERN PLAINS CHRISTMAS DAY THROUGH
SATURDAY NIGHT AHEAD OF THE SYSTEM. LIFT ASSOCIATED WITH THE JET
CIRCULATION AND DECENT LOW/MID LEVEL MOISTURE ADVECTION INTO THE
AREA SHOULD YIELD A PERIOD OF SNOW CHRISTMAS NIGHT THROUGH
SATURDAY. WILL CONTINUE THE CAUTIOUS...CONSERVATIVE APPROACH
REGARDING SNOW CHANCES THIS FORECAST CYCLE...BUT...IF MODELS
CONTINUE TO SHOW TONIGHTS IMPROVED AGREEMENT...CHANCES WILL HAVE
TO BE INCREASED. IN ADDITION...A STRONG COLD FRONT WILL CROSS THE
AREA DURING THE DAY SATURDAY. NORTH WINDS WILL INCREASE BEHIND THE
FRONT...WHICH COULD LEAD TO SOME BLOWING SNOW IF ENOUGH
ACCUMULATES.
BY SUNDAY...THE JET DYNAMICS AND ASSOCIATED LIFT WILL
WEAKEN...AND WITH THE CLOSED UPPER LOW EXPECTED TO BE WELL TO OUR
SOUTH...WILL LEAVE THE FORECAST DRY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 554 AM CST MON DEC 21 2015
FOR THE KLBF TERMINAL...EXPECT CIGS BELOW 1000 FT AGL THIS
MORNING..RISING TO 1500 FT AGL BY 17Z. CIGS WILL SCATTER OUT BY
MID AFTERNOON WITH CIGS OF 12000 TO 20000 FT AGL THROUGH 12Z
TUESDAY. FOR THE KVTN TERMINAL...EXPECT CIGS BELOW 1000 FT AGL
THROUGH 18Z...INCREASING TO 1200 FT AGL FOR MOST OF THE AFTERNOON
HOURS. CIGS WILL SCATTER OUT BY SUNSET WITH CIGS RANGING FROM
10000 TO 20000 FT AGL TONIGHT.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BUTTLER
SHORT TERM...BUTTLER
LONG TERM...TAYLOR
AVIATION...BUTTLER
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
342 AM CST MON DEC 21 2015
.SYNOPSIS...
ISSUED AT 340 AM CST MON DEC 21 2015
H5 ANALYSIS FROM EARLIER THIS EVENING HAD A LOW
AMPLITUDE PATTERN ACROSS THE CONUS. ZONAL FLOW WAS PRESENT FROM THE
WEST COAST...EWD TO THE MISSISSIPPI RIVER. EAST OF THE RIVER...LOW
AMPLITUDE RIDGING WAS PRESENT FROM SOUTH CAROLINA...NWD INTO SRN
QUEBEC. ACROSS THE CENTRAL AND SRN PLAINS...A DECENT SHORTWAVE
TROUGH WAS NOTED OVER SERN COLORADO. CURRENTLY...THIS FEATURE WAS
LOCATED OVER CENTRAL KS. AT THE SURFACE...A COLD FRONT HAS PASSED
WELL SOUTH OF THE FORECAST AREA THIS EVENING AND WAS ORIENTED ALONG
A LINE FROM DES MOINES IOWA...TO ST JOSEPH MISSOURI...TO WICHITA
KANSAS. ACROSS WESTERN AND NORTH CENTRAL NEBRASKA...A VEIL OF LOW
CLOUDINESS HAS SET IN ACROSS THE FORECAST AREA WITH CIGS GENERALLY
BETWEEN 500 TO 1000 FT AGL OVERNIGHT. SOME FOG WAS PRESENT IN THE
NEBRASKA PANHANDLE...ALONG THE WESTERN FLANK OF THE INVADING
STRATUS. TEMPERATURES WERE FAIRLY MILD FOR MID DECEMBER AS 3 AM CST
READINGS WERE GENERALLY IN THE 20S.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 340 AM CST MON DEC 21 2015
FOG POTENTIAL THIS MORNING...COUPLED WITH CLOUDINESS AND ITS
IMPACTS ON TEMPERATURES WILL BE THE MAIN FORECAST CHALLENGE. FOR
THIS MORNING WITH RESPECT TO FOG POTENTIAL...SUPPORT FOR AT LEAST
A PATCHY FOG MENTION CONTINUES INTO THE MID TO LATE MORNING
HOURS...ESPECIALLY OVER NORTH CENTRAL NEBRASKA PER THE LATEST
NAM12...SREF PROBABILITIES FCST...AS WELL AS THE HRRR SFC VISBY
FORECAST. ALBEIT...THE HRRR IS MOST AGGRESSIVE WITH THE
FOG...CONTINUING IT WELL INTO THE AFTERNOON HOURS ACROSS NORTHERN
AND NORTHEASTERN PORTIONS OF THE FORECAST AREA. THE HRRR DOES NOT
HAVE THE SUPPORT OF THE NAM12 AND SREF FOR EXTENDING FOG PAST
MIDDAY. THIS IS ALSO REFLECTED IN THE STATISTICAL GUIDANCE AS
WELL. THAT BEING SAID...WILL PLAN ON ENDING THE MENTION OF FOG
AFTER 16Z THIS MORNING. AS FOR TEMPERATURES TODAY...LOW LEVEL
CLOUDS SHOULD HANG ON WELL INTO THE AFTERNOON HOURS ACROSS
NORTHERN NEBRASKA PER NAM12 AND SREF H850-H900 LAYER RH
FORECASTS...AND THIS WILL HAVE A HUGE IMPACT ON HIGHS IN THE NORTH
TODAY. FOR THE SRN HALF OF THE FORECAST AREA...LOW CLOUDS SHOULD
BURN OFF BY MIDDAY...ALLOWING TEMPS TO REACH INTO THE 40S. FOR
TONIGHT...A SURFACE TROUGH WILL DEEPEN ACROSS EASTERN WYOMING WITH
A TIGHTENING SURFACE PRESSURE GRADIENT DEVELOPING OVERNIGHT. H925
AND H85 WINDS SUPPORT SOME MIXING AFTER MIDNIGHT...AND GUIDANCE
ACTUALLY SUPPORTS TEMPS WARMING IN THE WEST AND NORTHERN CWA
OVERNIGHT WITH LOWS OCCURRING DURING THE EVENING HRS. WITH THE
EXCEPTION OF THE PLATTE RIVER VALLEY WHERE UPPER TEENS ARE
EXPECTED...LOWS WILL GENERALLY BE IN THE MIDDLE 20S AND SHOULD BE
ACHIEVED DURING THE LATE EVENING TO THE EARLY OVERNIGHT HRS.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 340 AM CST MON DEC 21 2015
A COUPLE OF FAST MOVING SHORTWAVE DISTURBANCES WILL CROSS THE AREA
TUESDAY AND WEDNESDAY. AN INCREASE IN MID AND HIGH LEVEL
CLOUDINESS CAN BE EXPECTED DURING THIS TIME. DID ADD A SLIGHT
CHANCE FOR SNOW SHOWERS WEDNESDAY NIGHT. APPEARS TO BE ENOUGH
LIFT AND SATURATION PRESENT TO WARRANT A SLIGHT CHANCE DURING
THIS TIME. OTHERWISE A MILD PACIFIC AIRMASS IN PLACE WITH A
WESTERLY DOWNSLOPE CHINOOK TYPE LOW LEVEL FLOW. DESPITE DOWNSLOPE
FLOW...DID LIMIT DAYTIME HIGHS A BIT TO UPPER 30S AND 40S DUE TO
EXPECTED MID AND HIGH CLOUDS AND LINGERING SNOW COVER IN SPOTS.
MODELS HAVE COME INTO BETTER AGREEMENT TONIGHT FOR THE CHRISTMAS
EVE THROUGH SATURDAY PERIOD. GEM/GFS/ECMWF AND MOST GFS ENSEMBLE
MEMBERS INDICATE THAT A SIGNIFICANT SHORTWAVE WILL DIVE SOUTHEAST
FROM THE GULF OF ALASKA INTO THE DESERT SOUTHWEST BY CHRISTMAS
MORNING. ALL THREE OPERATIONAL MODELS CLOSE THE SYSTEM OFF AND
SLOWLY MOVE IT EASTWARD TOWARD WEST TX BY SUNDAY NIGHT. BROAD
SOUTHWEST FLOW ALOFT WITH EMBEDDED 140 KT JET STREAK WILL
OVERSPREAD THE CENTRAL AND SOUTHERN PLAINS CHRISTMAS DAY THROUGH
SATURDAY NIGHT AHEAD OF THE SYSTEM. LIFT ASSOCIATED WITH THE JET
CIRCULATION AND DECENT LOW/MID LEVEL MOISTURE ADVECTION INTO THE
AREA SHOULD YIELD A PERIOD OF SNOW CHRISTMAS NIGHT THROUGH
SATURDAY. WILL CONTINUE THE CAUTIOUS...CONSERVATIVE APPROACH
REGARDING SNOW CHANCES THIS FORECAST CYCLE...BUT...IF MODELS
CONTINUE TO SHOW TONIGHTS IMPROVED AGREEMENT...CHANCES WILL HAVE
TO BE INCREASED. IN ADDITION...A STRONG COLD FRONT WILL CROSS THE
AREA DURING THE DAY SATURDAY. NORTH WINDS WILL INCREASE BEHIND THE
FRONT...WHICH COULD LEAD TO SOME BLOWING SNOW IF ENOUGH
ACCUMULATES.
BY SUNDAY...THE JET DYNAMICS AND ASSOCIATED LIFT WILL
WEAKEN...AND WITH THE CLOSED UPPER LOW EXPECTED TO BE WELL TO OUR
SOUTH...WILL LEAVE THE FORECAST DRY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1133 PM CST SUN DEC 20 2015
IFR CEILINGS TO PERSIST AT KVTN OVERNIGHT UNTIL 16Z MONDAY. IN
ADDITION PATCHY FOG POSSIBLE WITH 3SM BR FCST UNTIL 10Z. AFTER
16Z...STRATUS SHOULD SCATTER OUT WITH VFR CONDITIONS. AT
KLBF...IFR CONDITIONS SHOULD PERSIST UNTIL 15Z...ALSO SCATTERING
OUT AND BECOMING VFR.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BUTTLER
SHORT TERM...BUTTLER
LONG TERM...TAYLOR
AVIATION...ROBERG
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1238 PM EST MON DEC 21 2015
.SYNOPSIS...
IT WILL BE CLOUDY TODAY WITH SPOTTY LIGHT RAIN SHOWERS THIS
AFTERNOON TO EVENING. HOWEVER...A MORE SOLID BATCH OF RAIN WILL
MOVE THROUGH THE REGION TUESDAY MORNING. THOUGH IT WILL REMAIN
UNSETTLED WEDNESDAY AND THURSDAY WITH OCCASIONAL
SHOWERS...TEMPERATURES WILL ALSO TREND WARMER. RECORD HIGHS ARE
POSSIBLE CHRISTMAS EVE DAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATED AT NOON... CURRENT FORECAST IS ON TRACK. RADAR IS SHOWING
SOME LIGHT RETURNS OVER OUR NORTHERN AND WESTERN COUNTIES BUT
LATEST OBSERVATIONS INDICATE THAT MOST OF THIS IS NOT REACHING THE
GROUND. LATEST HRRR SHOWS SOME LIGHT ECHOES ASSOCIATED WITH A WEAK
MID-LEVEL WAVE WEAKENING AS THEY MOVE EAST ACROSS CENTRAL NY LATER
THIS AFTERNOON. THE LATEST SREF ALSO INDICATE THAT POPS REMAIN
RATHER LOW THIS AFTERNOON... ESPECIALLY FOR LOCATIONS ALONG AND
EAST OF I-81 AND SOUTH OF SYRACUSE. OUR CURRENT FORECAST MATCHES
THESE TRENDS QUITE WELL AND HAVE NOT CHANGED POPS WITH THIS
UPDATE. MAIN CHANGE WAS TO NUDGE TEMPERATURES UP A FEW DEGREES
OVER THE LAKE PLANE WHERE READINGS ARE ALREADY APPROACHING 50 IN
MANY LOCATIONS. FARTHER SOUTH AND EAST TEMPERATURES ARE A BIT
COOLER AND SHOULD HOLD IN THE MID TO UPPER 40S. PREVIOUS
DISCUSSION IS BELOW.
635 AM UPDATE...
TEMPERATURES WERE ALREADY FORECAST TO CREEP UP THE LAST SEVERAL
HOURS...BUT THAT IS OCCURRING EVEN FASTER THAN HAD BEEN
FIGURED...ESPECIALLY IN THE FINGER LAKES AREA. I TWEAKED
TEMPERATURE GRIDS TO KEEP UP WITH OBS AND ALSO QUICKENED THE
PROGRESSION FROM MOSTLY CLOUDY TO PLAIN CLOUDY FOR MOST OF THE
DAY...REST OF FORECAST ON TRACK.
PREVIOUS DISCUSSION...
WE HAVE JUST BEGUN WHAT WILL BE AN EXTENDED PERIOD OF MILD AND
MOIST SOUTHWEST FLOW ALOFT...ONE RIDDLED WITH MULTIPLE EMBEDDED
WAVES AND RESULTANT CHANCES FOR SHOWERS.
AT 145 AM...MOISTURE IS NOW STREAMING IN ALOFT AS PER THE WATER
VAPOR IMAGERY EARLY THIS MORNING. FOR MOST LOCATIONS...LOW
TEMPERATURES FOR THE NIGHT ALREADY OCCURRED WHEN WE HAD INITIALLY
CLEAR SKY EARLY SUNDAY EVENING AND THUS SOME RADIATIONAL COOLING.
NOT THE CASE NOW...WITH HIGH THIN CLOUDS ALOFT...AND WARM AIR
ADVECTION UNDERWAY. TEMPERATURES WILL HOLD NEARLY STEADY OR CREEP
UP THE REMAINDER OF THE OVERNIGHT HOURS. THIS WILL MAKE HEADWAY
TOWARDS HIGHS IN THE LOWER TO MID 40S FOR TODAY...ABOUT 10 DEGREES
ABOVE CLIMATOLOGY. THAT IS ONLY THE BEGINNING COMPARED TO COMING
DAYS.
IN THE VERY QUICK FLOW ALOFT...A WEAK WAVE NOW NEAR KANSAS CITY
WILL ZIP NORTHEAST THROUGH OUR REGION ALREADY THIS AFTERNOON INTO
EVENING...HOWEVER...IT WILL HAVE TO COMBAT A LOT OF DRY AIR IN THE
LOWER LEVELS. THE BARK OF RADAR COVERAGE WILL LIKELY BE WORSE THAN
THE BITE...SINCE MUCH OF THE SHOWER ACTIVITY WILL COME IN THE FORM
OF VIRGA...DRYING UP BEFORE HITTING THE GROUND. WITH SOUTHERLY
WIND UPSLOPING INTO NORTHERN ONEIDA COUNTY...SHOWER CHANCES ARE
BETTER THERE...BUT MAJORITY OF OUR AREA WILL ONLY SEE RAIN AMOUNTS
ON THE ORDER OF HUNDREDTHS OF AN INCH. INDEED SOME IN NORTHEAST PA
TO FINGER LAKES NY COULD END UP WITH NOTHING AT ALL OTHER THAN
CLOUDS WITH THIS FIRST WAVE...HOWEVER...BETTER RAIN CHANCES ARE
QUICKLY EN ROUTE.
THOUGH MOST OF TONIGHT WILL BE QUIET...THE LEADING EDGE OF A
SECOND STRONGER WAVE WILL START TO SPREAD THIS BATCH OF RAIN INTO
THE AREA AROUND OR JUST BEFORE DAWN. AHEAD OF THAT SECOND
WAVE...CLOUDS...WARM AIR ADVECTION...AND SOUTH- SOUTHWESTERLY
BOUNDARY LAYER WIND WILL CONTINUE TONIGHT...SO TEMPERATURES WILL
BARELY MOVE WITH LOWS IN UPPER 30S- LOWER 40S.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
415 AM UPDATE...
WE CONTINUE WITH MOIST SOUTHWEST FLOW...WITH WARMING TEMPERATURES
AND BATCHES OF RAIN PASSING TUESDAY MORNING AND WEDNESDAY
AFTERNOON-EVENING.
A STRONG WAVE IS CURRENTLY CROSSING THE ROCKIES. YESTERDAY
MORNING IT WAS JUST ARRIVING AT THE WEST COAST AFTER TRAVERSING
OVER THE DATA-SPARSE PACIFIC. ONE OF THE CHALLENGES OF A VERY
BRISK FLOW ALOFT...IS MODELS GETTING AN ADEQUATE HANDLE OF QUICKLY
MOVING WAVES WELL UPSTREAM. AS EARLY AS ABOUT 24 HOURS
AGO...MODELS WERE HINTING AT THIS WAVE CAUSING SOME POTENTIAL FOR
RAIN...AND NOW WITH THE LATEST RUNS THEY HAVE REALLY GRABBED ONTO
IT AND HAVE EVEN QUICKENED ITS PACE BY A FEW HOURS. THE UPPER WAVE
WILL CATCH UP WITH A SURFACE LOW PRESSURE PASSING THROUGH THE
GREAT LAKES...WHILE GAINING SUPPORT FROM THE RIGHT ENTRANCE REGION
OF A STRONG JET MAX ALOFT.
IN COORDINATION WITH SURROUNDING OFFICES...RAIN CHANCES HAVE BEEN
BUMPED INTO 70-80 PERCENT RANGE FOR SEVERAL HOURS TUESDAY MORNING.
AREAL AVERAGE RAINFALL OF TWO TO FOUR TENTHS OF AN INCH AT THIS
POINT IS EXPECTED...BUT IT IS POSSIBLE THAT MESOSCALE ENHANCEMENT
COULD OCCUR SOMEWHERE WITHIN THE AREA /FORCED ASCENT VIA JET
SUPPORT OR OTHER METHODS/ TO PUSH LOCALIZED AMOUNTS PAST A HALF
INCH. STEADY MORNING RAIN WILL TRANSITION TO SPOTTY LINGERING
SHOWERS IN AFTERNOON. DESPITE ALL THE RAIN...STILL EXPECTING TO
MANAGE MID 40S TO NEAR 50 FOR HIGHS.
MODEL CONSENSUS HAS THE NEXT WAVE IN THE PARADE ARRIVING MIDDAY
WEDNESDAY THROUGH AFTERNOON-EVENING. RAIN AGAIN LOOKS LIKELY
THEN...FOR THE WHOLE AREA GENERALLY BUT ESPECIALLY FROM WYOMING
VALLEY-POCONOS IN PA THROUGH CATSKILLS-UPPER SUSQUEHANNA REGION IN
NY. TEMPERATURES WILL ALSO GO UP ANOTHER 4-8 DEGREES...WIDESPREAD
50S FOR HIGHS...FOLLOWED BY LOWS THAT MAY ACHIEVE RECORD HIGH
MINIMUMS WEDNESDAY NIGHT /UPPER 40S-LOWER 50S/.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
0240 AM UPDATE...NO MAJOR CHANGES TO LONG RANGE FORECAST. ONLY
MODIFICATION WAS TO BUMP HIGHS UP A COUPLE DEGREES FOR CHRISTMAS
EVE DAY. HIGHS THIS DAY LOOK TO BE IN THE LOWER TO MID 60S ACROSS
THE AREA...POTENTIALLY BREAKING RECORDS. FOR FURTHER DETAILS, SEE
DISCUSSION BELOW.
300 PM SUNDAY UPDATE...
WITH HIGH PRESSURE OFF THE SOUTHEAST COAST, AND A TROF IN THE
SOUTHWEST US, A DEEP SOUTHWEST FLOW WILL CONTINUE THROUGH THE
PERIOD. THE RESULT WILL REMAIN UNSETTLED WEATHER WITH CHANCES FOR
RAIN SHOWERS BUT ALSO MILD WEATHER, WITH RECORD WARMTH POSSIBLE
BY CHRISTMAS EVE DAY.
AFTER A LULL TUESDAY NIGHT, A NEW DISTURBANCE WILL MOVE INTO THE
AREA BY WEDNESDAY WITH MORE SHOWERS POSSIBLE. BY THIS TIME
HOWEVER A MUCH DEEPER TROF WILL DIG OVER THE UPPER MIDWEST, WHICH
WILL KEEP CHANCES FOR RAIN HIGH WEDNESDAY INTO THE FIRST PART OF
THURSDAY. DESPITE THE CLOUDS AND RAIN CHANCES WITH 850 TEMPS IN
THE +10C TO +12C RANGE BOTH DAYS, HIGHS WILL BE IN THE 50S AND
60S. RIGHT NOW CHRISTMAS EVE DAY LOOKS LIKE OUR BEST SHOT AT
BREAKING RECORDS, WITH FORECAST HIGHS IN THE 60S FOR MOST OF THE
AREA.
AS THE UPPER LEVEL TROF MENTIONED ABOVE LIFTS NORTH BY FRIDAY,
HIGH PRESSURE WILL BRING DRIER AND NOT QUITE AS MILD WEATHER TO
THE AREA FRIDAY AND SATURDAY. STILL WITH A PACIFIC ORIGIN,HIGHS
BOTH DAYS WILL STILL BE WELL ABOVE AVERAGE OR WELL INTO THE 40S!
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
1230 PM UPDATE...
VFR THROUGH LATE THIS AFTERNOON WITH A FEW SPRINKLES FROM TIME TO
TIME NY TERMINALS, AS CIGS LOWER FROM AROUND 10,000 FEET TO UNDER
5,000 FEET. BY TONIGHT AS WE CONTINUE TO MOISTEN UP, MVFR CIGS
WILL BECOME POSSIBLE AFTER 0Z AT MOST OF THE TERMINALS WITH THE
EXCEPTION OF KSYR AND KRME. AT KSYR AND KRME WHILE IT WILL BE
CLOSE, THE SOUTHERLY COMPONENT OF THE WIND MAY KEEP CIGS JUST
ABOVE MVFR, BARELY.
RAIN WILL OVERSPREAD THE TERMINALS BETWEEN 09Z AND 12Z SOUTHERN
TERMINALS, AND BY 14Z UP NORTH, TUESDAY. AS THIS HAPPENS CIGS WILL
LOWER A BIT MORE, WITH WIDESPREAD MVFR CIGS AND VSBYS EXPECTED. AT
THE HILLTOP TERMINALS OF KITH AND KBGM, IFR CIGS AND VSBYS
POSSIBLE IN RAIN AND MIST.
.OUTLOOK...
WED-THUR...RESTRICTIONS LIKELY AT TIMES AS A SERIES OF WAVES MOVE
THROUGH BRINGING PERIODS OF RAIN AND SHOWERS.
FRI...VFR.
SAT...RESTRICTIONS POSSIBLE IN RAIN.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MDP
NEAR TERM...MDP/MSE
SHORT TERM...MDP
LONG TERM...HEDEN/PCF
AVIATION...HEDEN
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1216 PM EST MON DEC 21 2015
.SYNOPSIS...
IT WILL BE CLOUDY TODAY WITH SPOTTY LIGHT RAIN SHOWERS THIS
AFTERNOON TO EVENING. HOWEVER...A MORE SOLID BATCH OF RAIN WILL
MOVE THROUGH THE REGION TUESDAY MORNING. THOUGH IT WILL REMAIN
UNSETTLED WEDNESDAY AND THURSDAY WITH OCCASIONAL
SHOWERS...TEMPERATURES WILL ALSO TREND WARMER. RECORD HIGHS ARE
POSSIBLE CHRISTMAS EVE DAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATED AT NOON... CURRENT FORECAST IS ON TRACK. RADAR IS SHOWING
SOME LIGHT RETURNS OVER OUR NORTHERN AND WESTERN COUNTIES BUT
LATEST OBSERVATIONS INDICATE THAT MOST OF THIS IS NOT REACHING THE
GROUND. LATEST HRRR SHOWS SOME LIGHT ECHOES ASSOCIATED WITH A WEAK
MID-LEVEL WAVE WEAKENING AS THEY MOVE EAST ACROSS CENTRAL NY LATER
THIS AFTERNOON. THE LATEST SREF ALSO INDICATE THAT POPS REMAIN
RATHER LOW THIS AFTERNOON... ESPECIALLY FOR LOCATIONS ALONG AND
EAST OF I-81 AND SOUTH OF SYRACUSE. OUR CURRENT FORECAST MATCHES
THESE TRENDS QUITE WELL AND HAVE NOT CHANGED POPS WITH THIS
UPDATE. MAIN CHANGE WAS TO NUDGE TEMPERATURES UP A FEW DEGREES
OVER THE LAKE PLANE WHERE READINGS ARE ALREADY APPROACHING 50 IN
MANY LOCATIONS. FARTHER SOUTH AND EAST TEMPERATURES ARE A BIT
COOLER AND SHOULD HOLD IN THE MID TO UPPER 40S. PREVIOUS
DISCUSSION IS BELOW.
635 AM UPDATE...
TEMPERATURES WERE ALREADY FORECAST TO CREEP UP THE LAST SEVERAL
HOURS...BUT THAT IS OCCURRING EVEN FASTER THAN HAD BEEN
FIGURED...ESPECIALLY IN THE FINGER LAKES AREA. I TWEAKED
TEMPERATURE GRIDS TO KEEP UP WITH OBS AND ALSO QUICKENED THE
PROGRESSION FROM MOSTLY CLOUDY TO PLAIN CLOUDY FOR MOST OF THE
DAY...REST OF FORECAST ON TRACK.
PREVIOUS DISCUSSION...
WE HAVE JUST BEGUN WHAT WILL BE AN EXTENDED PERIOD OF MILD AND
MOIST SOUTHWEST FLOW ALOFT...ONE RIDDLED WITH MULTIPLE EMBEDDED
WAVES AND RESULTANT CHANCES FOR SHOWERS.
AT 145 AM...MOISTURE IS NOW STREAMING IN ALOFT AS PER THE WATER
VAPOR IMAGERY EARLY THIS MORNING. FOR MOST LOCATIONS...LOW
TEMPERATURES FOR THE NIGHT ALREADY OCCURRED WHEN WE HAD INITIALLY
CLEAR SKY EARLY SUNDAY EVENING AND THUS SOME RADIATIONAL COOLING.
NOT THE CASE NOW...WITH HIGH THIN CLOUDS ALOFT...AND WARM AIR
ADVECTION UNDERWAY. TEMPERATURES WILL HOLD NEARLY STEADY OR CREEP
UP THE REMAINDER OF THE OVERNIGHT HOURS. THIS WILL MAKE HEADWAY
TOWARDS HIGHS IN THE LOWER TO MID 40S FOR TODAY...ABOUT 10 DEGREES
ABOVE CLIMATOLOGY. THAT IS ONLY THE BEGINNING COMPARED TO COMING
DAYS.
IN THE VERY QUICK FLOW ALOFT...A WEAK WAVE NOW NEAR KANSAS CITY
WILL ZIP NORTHEAST THROUGH OUR REGION ALREADY THIS AFTERNOON INTO
EVENING...HOWEVER...IT WILL HAVE TO COMBAT A LOT OF DRY AIR IN THE
LOWER LEVELS. THE BARK OF RADAR COVERAGE WILL LIKELY BE WORSE THAN
THE BITE...SINCE MUCH OF THE SHOWER ACTIVITY WILL COME IN THE FORM
OF VIRGA...DRYING UP BEFORE HITTING THE GROUND. WITH SOUTHERLY
WIND UPSLOPING INTO NORTHERN ONEIDA COUNTY...SHOWER CHANCES ARE
BETTER THERE...BUT MAJORITY OF OUR AREA WILL ONLY SEE RAIN AMOUNTS
ON THE ORDER OF HUNDREDTHS OF AN INCH. INDEED SOME IN NORTHEAST PA
TO FINGER LAKES NY COULD END UP WITH NOTHING AT ALL OTHER THAN
CLOUDS WITH THIS FIRST WAVE...HOWEVER...BETTER RAIN CHANCES ARE
QUICKLY EN ROUTE.
THOUGH MOST OF TONIGHT WILL BE QUIET...THE LEADING EDGE OF A
SECOND STRONGER WAVE WILL START TO SPREAD THIS BATCH OF RAIN INTO
THE AREA AROUND OR JUST BEFORE DAWN. AHEAD OF THAT SECOND
WAVE...CLOUDS...WARM AIR ADVECTION...AND SOUTH- SOUTHWESTERLY
BOUNDARY LAYER WIND WILL CONTINUE TONIGHT...SO TEMPERATURES WILL
BARELY MOVE WITH LOWS IN UPPER 30S- LOWER 40S.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
415 AM UPDATE...
WE CONTINUE WITH MOIST SOUTHWEST FLOW...WITH WARMING TEMPERATURES
AND BATCHES OF RAIN PASSING TUESDAY MORNING AND WEDNESDAY
AFTERNOON-EVENING.
A STRONG WAVE IS CURRENTLY CROSSING THE ROCKIES. YESTERDAY
MORNING IT WAS JUST ARRIVING AT THE WEST COAST AFTER TRAVERSING
OVER THE DATA-SPARSE PACIFIC. ONE OF THE CHALLENGES OF A VERY
BRISK FLOW ALOFT...IS MODELS GETTING AN ADEQUATE HANDLE OF QUICKLY
MOVING WAVES WELL UPSTREAM. AS EARLY AS ABOUT 24 HOURS
AGO...MODELS WERE HINTING AT THIS WAVE CAUSING SOME POTENTIAL FOR
RAIN...AND NOW WITH THE LATEST RUNS THEY HAVE REALLY GRABBED ONTO
IT AND HAVE EVEN QUICKENED ITS PACE BY A FEW HOURS. THE UPPER WAVE
WILL CATCH UP WITH A SURFACE LOW PRESSURE PASSING THROUGH THE
GREAT LAKES...WHILE GAINING SUPPORT FROM THE RIGHT ENTRANCE REGION
OF A STRONG JET MAX ALOFT.
IN COORDINATION WITH SURROUNDING OFFICES...RAIN CHANCES HAVE BEEN
BUMPED INTO 70-80 PERCENT RANGE FOR SEVERAL HOURS TUESDAY MORNING.
AREAL AVERAGE RAINFALL OF TWO TO FOUR TENTHS OF AN INCH AT THIS
POINT IS EXPECTED...BUT IT IS POSSIBLE THAT MESOSCALE ENHANCEMENT
COULD OCCUR SOMEWHERE WITHIN THE AREA /FORCED ASCENT VIA JET
SUPPORT OR OTHER METHODS/ TO PUSH LOCALIZED AMOUNTS PAST A HALF
INCH. STEADY MORNING RAIN WILL TRANSITION TO SPOTTY LINGERING
SHOWERS IN AFTERNOON. DESPITE ALL THE RAIN...STILL EXPECTING TO
MANAGE MID 40S TO NEAR 50 FOR HIGHS.
MODEL CONSENSUS HAS THE NEXT WAVE IN THE PARADE ARRIVING MIDDAY
WEDNESDAY THROUGH AFTERNOON-EVENING. RAIN AGAIN LOOKS LIKELY
THEN...FOR THE WHOLE AREA GENERALLY BUT ESPECIALLY FROM WYOMING
VALLEY-POCONOS IN PA THROUGH CATSKILLS-UPPER SUSQUEHANNA REGION IN
NY. TEMPERATURES WILL ALSO GO UP ANOTHER 4-8 DEGREES...WIDESPREAD
50S FOR HIGHS...FOLLOWED BY LOWS THAT MAY ACHIEVE RECORD HIGH
MINIMUMS WEDNESDAY NIGHT /UPPER 40S-LOWER 50S/.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
0240 AM UPDATE...NO MAJOR CHANGES TO LONG RANGE FORECAST. ONLY
MODIFICATION WAS TO BUMP HIGHS UP A COUPLE DEGREES FOR CHRISTMAS
EVE DAY. HIGHS THIS DAY LOOK TO BE IN THE LOWER TO MID 60S ACROSS
THE AREA...POTENTIALLY BREAKING RECORDS. FOR FURTHER DETAILS, SEE
DISCUSSION BELOW.
300 PM SUNDAY UPDATE...
WITH HIGH PRESSURE OFF THE SOUTHEAST COAST, AND A TROF IN THE
SOUTHWEST US, A DEEP SOUTHWEST FLOW WILL CONTINUE THROUGH THE
PERIOD. THE RESULT WILL REMAIN UNSETTLED WEATHER WITH CHANCES FOR
RAIN SHOWERS BUT ALSO MILD WEATHER, WITH RECORD WARMTH POSSIBLE
BY CHRISTMAS EVE DAY.
AFTER A LULL TUESDAY NIGHT, A NEW DISTURBANCE WILL MOVE INTO THE
AREA BY WEDNESDAY WITH MORE SHOWERS POSSIBLE. BY THIS TIME
HOWEVER A MUCH DEEPER TROF WILL DIG OVER THE UPPER MIDWEST, WHICH
WILL KEEP CHANCES FOR RAIN HIGH WEDNESDAY INTO THE FIRST PART OF
THURSDAY. DESPITE THE CLOUDS AND RAIN CHANCES WITH 850 TEMPS IN
THE +10C TO +12C RANGE BOTH DAYS, HIGHS WILL BE IN THE 50S AND
60S. RIGHT NOW CHRISTMAS EVE DAY LOOKS LIKE OUR BEST SHOT AT
BREAKING RECORDS, WITH FORECAST HIGHS IN THE 60S FOR MOST OF THE
AREA.
AS THE UPPER LEVEL TROF MENTIONED ABOVE LIFTS NORTH BY FRIDAY,
HIGH PRESSURE WILL BRING DRIER AND NOT QUITE AS MILD WEATHER TO
THE AREA FRIDAY AND SATURDAY. STILL WITH A PACIFIC ORIGIN,HIGHS
BOTH DAYS WILL STILL BE WELL ABOVE AVERAGE OR WELL INTO THE 40S!
&&
.AVIATION /17Z MONDAY THROUGH FRIDAY/...
630 AM UPDATE...
HIGH CLOUDS OVER THE AREA WILL LOWER TO A DECK AROUND 4-5 KFT BY
LATER TODAY AS AN INITIAL WAVE MOVES THROUGH. EXPECT CONDITIONS TO
REMAIN VFR HOWEVER. THIS FIRST WAVE MAY PRODUCE A FEW SHOWERS OVER
CENTRAL NY TERMINALS THOUGH CONFIDENCE NOT HIGH ENOUGH TO WARRANT INCLUSION
IN TAFS. A STRONGER WAVE APPROACHES LATE TONIGHT WITH CIGS
LOWERING TO MVFR FOR ALL SITES EXCEPT KSYR. RAIN MOVES INTO THE
THREE SOUTHERN TERMINALS BEFORE 12Z AND REMAINING TERMINALS AFTER
12Z TUESDAY MORNING.
WINDS WILL BE S/SE BECOMING MORE S/SW BY THIS AFTERNOON AND
GENERALLY BE AT SPEEDS OF AROUND 8-13 KNOTS WITH HIGHER GUSTS AT
TIMES UP TO 20 KNOTS FOR KITH/KBGM.
.OUTLOOK...
TUE-THUR...RESTRICTIONS LIKELY AT TIMES AS A SERIES OF WAVES MOVE
THROUGH BRINGING PERIODS OF RAIN AND SHOWERS.
FRI...VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MDP
NEAR TERM...MDP/MSE
SHORT TERM...MDP
LONG TERM...HEDEN/PCF
AVIATION...PCF/TAC
AREA FORECAST DISCUSSION
NWS RALEIGH NC
806 PM EST TUE DEC 22 2015
.SYNOPSIS...A WEDGE FRONT WILL REMAIN QUASI-STATIONARY OVER THE
PIEDMONT THROUGH TONIGHT...THEN BE OVERTAKEN BY A MARITIME WARM
FRONT THAT WILL SURGE ACROSS THE CAROLINAS AND VIRGINIA ON
WEDNESDAY. ANOMALOUSLY STRONG SUB-TROPICAL HIGH PRESSURE OVER THE
WEST-CENTRAL ATLANTIC OCEAN WILL THEN DIRECT UNSEASONABLY WARM AND
MOIST SOUTHERLY FLOW THROUGHOUT THE SOUTHEASTERN UNITED STATES
THROUGH CHRISTMAS.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 315 PM TUESDAY...
...HEAVY RAIN AND SOME LOCALIZED FLOODING POSSIBLE OVER THE WESTERN
PIEDMONT LATE TONIGHT INTO WEDNESDAY...
EARLIER RAINFALL IS NOW NEAR THE COAST AS THE ASSOCIATED SHEAR AXIS
AND DEEPEST MOISTURE HAVE SHIFTED EAST. SLIGHTLY DRIER MID LEVEL
AIR...WHICH HAS AIDED PERIODS OF DENSE FOG IN THE WEDGE AIRMASS
OVER THE WESTERN PIEDMONT...WILL GIVE WAY TO ANOTHER SURGE OF DEEP
MOISTURE ACCOMPANYING ANOTHER WAVE IN THE SOUTHWEST FLOW. PW WILL
INCREASE BACK TO NEAR 1.8 INCHES...WHICH IS NEARLY A CLIMATOLOGICAL
MAX FOR THIS TIME OF YEAR. WHILE THE MAIN AMPLIFICATION OF THE UPPER
TROUGH MOVING OUT OF THE SOUTHERN US WILL BE WELL WEST OF HERE... A
NOTABLE SHORTWAVE CURRENTLY OVER THE LOWER MISSISSIPPI VALLEY IS
FORECAST TOP LIFT ALONG THE SPINE OF THE APPALACHIANS AND SERVE AS A
FOCUS FOR HEAVY RAINFALL. THE WESTERN PIEDMONT LIES ON THE EAST
EDGE OF THE GENERAL MODEL CONSENSUS OF 2+ INCHES OF QPF...BUT GIVEN
THE ANOMALIES IN THIS PATTERN AND THE 1-2 INCHES THAT FEEL LAST
NIGHT...A FLASH FLOOD WATCH WILL BE ISSUED STARTING AT MIDNIGHT
TONIGHT FOR THE WESTERN PIEDMONT. PRIOR TO THE RAIN...THE HRRR SHOWS
WIDESPREAD FOG SETTLING BACK IN WITHIN THE WEDGE AIRMASS. A DENSE
FOG ADVISORY MAY BE NEEDED BEFORE PRECIP SPREADS IN FROM THE SOUTH
AND HELPS TO AT LEAST MIX OUT THE 1/4 MILE VSBYS. TEMPS WILL HOLD
STEADY OR RISE LATE TONIGHT WITH THE STRENGTHENING WARM
ADVECTION..WITH READINGS IN THE UPPER 50S TO UPPER 60S.
&&
.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 300 PM TUESDAY...
ONGOING PRECIP WEDNESDAY MORNING WILL BE FOCUSED ACROSS THE WESTERN
PIEDMONT AS A DISTURBANCE LIFTS ALONG THE APPALACHIANS. INCREDIBLY
HIGH PW DISCUSSED INT HE NEAR TERM FORECAST WILL REMAIN OVER THE
AREA WITH NO AIRMASS CHANGE IN SIGHT. THE FOCUS FOR PRECIP...LIKELY
MORE CONVECTIVE IN NATURE...SHOULD SHIFT EAST DURING THE DAY AS THE
DISTURBANCE LIFTS OFF TO THE NORTH AND A TRAILING SHEAR AXIS MOVES
EAST. MID-LEVEL LAPSE RATES ARE EXPECTED TO BE WEAK EAST OF THE
APPALACHIANS (THOUGH THE GFS FORECASTS 6+ C/KM)...BUT GIVEN TEMPS
CLIMBING INTO THE MID 70S AND DEWPOINTS APPROACHING 70...FORECAST
SOUNDINGS SHOW A RANGE OF 500-1000 J/KG OF MUCAPE IN THE COASTAL
PLAIN WEDNESDAY AFTERNOON. EVEN IF THIS IS A LITTLE
OVERDONE...CONVECTION SHOULD BE UNINHIBITED AND COULD TAP INTO THE
40-50KT DEEP SHEAR AND RESULT IN AT LEAST AN ISOLATED SEVERE THREAT.
CONFIDENCE IS LOW GIVEN THE TIME OF YEAR...BUT THE PATTERN IS
UNUSUALLY WARM AND MOIST. EVEN WITHOUT STRONG STORMS...CONVECTIVE
CELLS WILL BE CAPABLE OF PRODUCING ANOTHER INCH OR MORE OF RAIN IN
ISOLATED AREAS...SO A LOCALIZED FLASH FLOOD THREAT MAY STILL BE
THERE.
THE OVERALL COVERAGE OF PRECIP WILL LESSEN WEDNESDAY NIGHT...THOUGH
MODELS CONTINUE TO SHOW POTENTIAL FOR SOME SCATTERED SHOWERS WELL ON
THROUGH THE NIGHT. LOWS WILL BE VERY MILD IN THE MID AND UPPER 60S.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 200 PM TUESDAY...
THU AND THU NIGHT: STILL SOME DIFFERENCES IN THE MODELS WITH RESPECT
TO RAIN...THUS THERE IS STILL SOME UNCERTAINTY. HOWEVER...IT IS
LOOKING LIKE THURSDAY COULD BE RELATIVELY DRY...BUT WILL KEEP A
CHANCE OF SOME RAIN IN THE FORECAST. RAIN SHOULD NOT BE NEARLY AS
WIDESPREAD AS IN PRECEDING DAYS. BEST CHANCES FOR CONVECTION WILL
BE IN THE NORTHWEST...ESPECIALLY IN THE AFT/EVE AND INTO THE
OVERNIGHT. HIGHEST TEMPERATURES OF THE LONG TERM ARE STILL EXPECTED
ON THURSDAY AS THE SOUTHERLY WARM ADVECTION PEAKS. HIGHS IN THE LOW
TO MID 70S NW TO AROUND 80 DEGREES IN THE SE. LOWS GENERALLY IN THE
MID 60S.
FRI THROUGH SUN: AS OF THE LATEST MEDIUM RANGE MODEL RUNS...THIS
PERIOD WILL LIKELY BE DOMINATED BY SUB-TROPICAL RIDGING ALOFT OVER
THE SOUTHEAST U.S.. SOUTHERLY TO SOUTHWESTERLY RETURN FLOW AROUND
THE SURFACE HIGH WILL CONTINUE TO USHER WARM MOIST AIR INTO THE
REGION...RESULTING IN A VERY WARM AND MOIST PERIOD FOR THIS TIME OF
YEAR. THE OCCASIONAL UPPER LEVEL DISTURBANCE RIDING THE RIDGE MAY
GENERATING ENOUGH LIFT IN THE ANOMALOUSLY WARM MOIST AIRMASS TO KICK
OFF SOME SHOWERS...MAINLY IN THE AFT/EVE HOURS. THE GENERAL PRECIP
TREND FOR THIS PERIOD WILL BE CHARACTERIZED BY A LULL DURING THE
OVERNIGHT AND MORNING HOURS AND HIGHEST CHANCES DURING THE AFT/EVE.
THE INITIAL FRONTAL SURGE THAT WAS ORIGINALLY EXPECTED TO PUSH SOUTH
INTO THE AREA ON FRIDAY WILL LIKELY STAY WELL TO THE NORTH THROUGH
AT LEAST SUNDAY EVENING. LOWS THROUGH THE PERIOD WILL BE FAIRLY
CONSISTENT...AND WELL ABOVE NORMAL...IN THE MID 50S TO LOW 60S.
HIGHS WILL LIKELY FLUCTUATE A BIT MORE...BUT GENERALLY STAY BETWEEN
THE MID 60S AND UPPER 70S...WHICH IS 10-15 DEGREES ABOVE NORMAL FOR
LATE DECEMBER.
MONDAY AND MONDAY NIGHT...THE GFS AND ECMWF VARY ON WHETHER THEY
THINK A SECONDARY SURGE WILL PUSH FAR ENOUGH SOUTH TO MOVE INTO
CENTRAL NC FOR THE BEGINNING OF THE WEEK. WILL HOLD OFF ON MAKING
ANY DRASTIC CHANGES TO THE PREVIOUS FORECAST FOR EARLY NEXT WEEK
UNTIL THERE IS BETTER AGREEMENT ONE WAY OR THE OTHER.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
AS OF 740 PM TUESDAY...
24 HOUR TAF PERIOD: ADVERSE AVIATION CONDITIONS ARE EXPECTED TO
CONTINUE FOR THE 24 HOUR TAF PERIOD... AS A WARM MOIST AIRMASS
REMAINS OVER CENTRAL NC.
SUB-VFR CIGS AND VISBYS ARE EXPECTED TO EXPAND/REDEVELOP TONIGHT
ACROSS ALL OF CENTRAL NC... WITH THE WORST CONDITIONS AT KGSO/KINT
(ALREADY LIFR). ANOTHER ROUND OF RAIN/SHOWERS... WITH PERHAPS A
FEW EMBEDDED STORMS... IS EXPECTED TO MOVE INTO THE AREA LATE
TONIGHT... FIRST ACROSS THE WESTERN TERMINALS... THEN SPREADING EAST
THROUGH THE MORNING INTO THE AFTERNOON WEDNESDAY.
CIGS/VISBYS AT KGSO/KINT ARE EXPECTED TO REMAIN IN THE LIFR CATEGORY
FOR MOST OF THE TAF PERIOD... WITH POSSIBLY SOME BRIEF IMPROVEMENT
ACTUALLY AS THE PRECIP MOVES INTO THE AREA LATE TONIGHT... THEN
AGAIN BY MID TO LATE AFTERNOON WEDNESDAY (THOUGH LIKELY ONLY
IMPROVING TO IFR). IN ADDITION TO THE POSSIBLE SUB-VFR CONDITIONS...
WE MAY SEE SOME MARGINAL LLWS CONDITIONS IN THE 10Z TO 16Z
WEDNESDAY KGSO/KINT... AS WINDS AT AROUND 2 KFT STRENGTHEN TO AROUND
30 TO 35 KTS. HOWEVER... WITH GENERALLY UNIDIRECTIONAL LOW
LEVEL FLOW AND SURFACE WINDS SPEEDS INCREASING DURING THAT TIME
AS WELL... WILL NOT INCLUDE ANY MENTION OF LLWS AT KGSO/KINT.
FURTHER EAST AT KRDU/KFAY/KRWI... WE SHOULD SEE IMPROVEMENT IN CIGS
AND VISBYS BY MID TO LATE MORNING INTO THE AFTERNOON... WITH
POSSIBLY SOME VFR CONDITIONS AT KRWI AND KFAY BY MID AFTERNOON.
HOWEVER... EXPECT WE WILL SEE SOME SCATTERED TO NUMEROUS SHOWERS...
WITH ISOLATED STORMS FROM MID MORNING THROUGH MID AFTERNOON... AND
INCREASING SOUTHERLY WINDS... WITH GUSTS OF UP TO 20 TO 25 KTS
POSSIBLE.
OUTLOOK: A MOIST DEEP SOUTHWESTERLY FLOW DOWNSTREAM OF THE LONG WAVE
TROUGH IN PLACE ACROSS THE CENTRAL CONUS WILL SUPPORT A PROLONGED
PERIOD OF ADVERSE AVIATION CONDITIONS THROUGH MUCH OF THE PERIOD.
SUB-VFR CONDITIONS IN LOW CLOUDS/STRATUS WILL ALSO BE LIKELY EACH
MORNING... ALONG WITH THE TREAT OF SOME SHOWERS EACH DAY.
&&
.CLIMATE...
HERE ARE THE AREA RECORD MAXIMUMS AND HIGH MINIMUMS FOR DECEMBER 24TH
AND 25TH. RECORDS HAVE BEEN KEPT IN THE GREENSBORO AREA SINCE
1903... IN THE RALEIGH AREA SINCE 1887... AND IN THE FAYETTEVILLE
AREA SINCE 1910.
DEC 24: RECORD MAXIMUM HIGH MINIMUM
GREENSBORO 71 (1964) 52 (1904)
RALEIGH 75 (1931) 59 (1891)
FAYETTEVILLE 78 (1931) 66 (1990)
DEC 25: RECORD MAXIMUM HIGH MINIMUM
GREENSBORO 74 (1955) 58 (1932)
RALEIGH 75 (1955) 63 (1932)
FAYETTEVILLE 79 (1932) 68 (1932)
&&
.RAH WATCHES/WARNINGS/ADVISORIES... NONE.
&&
$$
SYNOPSIS...2
NEAR TERM...22
SHORT TERM...22
LONG TERM...10
AVIATION...77/22
CLIMATE...HARTFIELD/BLAES
AREA FORECAST DISCUSSION
NWS RALEIGH NC
310 PM EST MON DEC 21 2015
.SYNOPSIS... A SOUTHERLY FLOW OF WARMER AND MORE MOIST AIR WILL
DEVELOP TODAY AND PERSIST FOR MUCH OF THE WEEK. MEANWHILE...A COLD
FRONT WILL APPROACH THE AREA FROM THE WEST ON TUESDAY...THEN STALL
OVER THE REGION.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 305 PM MONDAY...
WARM ADVECTION...AHEAD OF A COLD FRONT IN THE MISSISSIPPI VALLEY
REGION...CONTINUES ACROSS THE SOUTHEAST US IN DEEP SOUTHEASTERLY
FLOW. A LIGHT BAND OF RAIN ASSOCIATED WITH A NARROW REGION OF 700MB
MOISTURE JUST WEST OF THE TRIAD MAY PRODUCE SOME VERY LIGHT RAIN
THIS AFTERNOON...BUT THE LOW-LEVELS ARE STILL RATHER DRY AND ITS
TAKING SOME TIME FOR THE PRECIP TO REACH THE GROUND. THUS...A LARGE
MAJORITY OF THE CWA WILL BE DRY THIS EVENING. MODELS SHOW A LARGE
AREA OF RAIN BREAKING OUT OUT OVER GA/AL THIS EVENING AND SPREADING
NORTHEAST INTO THE CAROLINAS AFTER MIDNIGHT AS A SHORTWAVE PASSES TO
OUR NORTHWEST AND A LOW LEVEL JET INCREASES THE ISENTROPIC LIFT/WARM
OVER OUR REGION. THE HRRR SHOWS THE PRECIP MOVING INTO THE
SOUTHERN/WESTERN PIEDMONT AROUND 08Z. THIS IS GENERALLY IN AGREEMENT
WITH THE LARGE SCALE MODELS...WHICH SHOW THE HEAVIEST RAINFALL
AMOUNTS...0.50-0.75"...ACROSS THE SOUTHERN PIEDMONT THROUGH 12Z
TUESDAY. PW WILL BE INCREASING TO WELL OVER 1.5"...SO SOME OF THE
RAIN COULD BE LOCALLY HEAVIER...BUT INSTABILITY LOOKS VERY MEAGER
WITH WEAK LAPSE RATES ALOFT DESPITE THE WARM ADVECTION AND LOW LEVEL
JETTING. WITH DEWPOINTS RECOVERING AHEAD OF THE PRECIP TONIGHT...
LOWS SHOULD END UP IN THE MID 40S NORTHWEST TO MID 50S.
&&
.SHORT TERM /TUESDAY AND TUESDAY NIGHT/...
AS OF 305 PM MONDAY...
ONGOING SHOWERS WILL SHIFT NORTH AND EAST TUESDAY MORNING AS THE LOW
LEVEL JET SURGES OFF TO THE NORTHEAST. BUFR SOUNDINGS SHOW SOME
MARKEDLY DRIER MID-LEVEL AIR THAT SHOULD RENDER MUCH OF THE AIR FREE
OF PRECIP BY TUESDAY AFTERNOON...ALTHOUGH SHALLOW ISENTROPIC LIFT
COULD STILL SUPPORT SOME DRIZZLE ACROSS THE WESTERN PIEDMONT. THIS
FORECAST WILL DRASTICALLY CUT BACK POPS AFTER 18Z...AND CHANCE POPS
MAY STILL BE TOO HIGH. ALL GUIDANCE GIVES HIGHS IN THE 60S BY
TUESDAY AFTERNOON...BUT GIVEN THAT THERE WILL BE NO AIRMASS CHANGE
AFTER THE PRECIPITATION TONIGHT...ITS KINDA HARD TO UNDERSTAND THE
NORTHWEST PIEDMONT REACHING 60. MET GUIDANCE IS ONE OF THE ONLY
MODELS TO GIVE UPPER 50S...SO WILL GO WITH UPPER 50S NORTHWEST TO
NEAR 70 SOUTHEAST.
ANOTHER ROUND OF PRECIP WILL BE HEADING OUT EAST TUESDAY NIGHT AS A
DEEPER TROUGH MOVES THROUGH THE CENTRAL US AND THE LOW LEVEL
JET/WARM ADVECTION INTENSIFY OVER THE SOUTHEAST US ONCE AGAIN. THE
PREFERRED GFS AND ECMWF TAKE THE HEAVIEST QPF THROUGH THE MOUNTAINS
AS THE LOW LEVEL FLOW BACKS AROUND TO MORE SOUTHEASTERLY...BUT WITH
PW STILL WELL ABOVE NORMAL AND STRONG WARM ADVECTION...WILL CARRY
LIKELY POPS AFTER 00Z AND CATEGORICAL ACROSS THE WEST. THE
PROBABILITY THUNDER STILL LOOKS LOW GIVEN WEAK LAPSE RATES..THOUGH
THE CHANCE MAY BE SLIGHTLY HIGHER THAN TONIGHT WITH A STRONGER LOW
LEVEL JET. IT STILL LOOKS TOO ISOLATED TO INCLUDE IN THE FORECAST
FOR NOW. LOWS WILL BE MILDER IN THE UPPER 60S TO LOWER 70S.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
AS OF 1055 AM MONDAY...
...WIDESPREAD RAIN WED INTO WED NIGHT...
...ABOVE NORMAL TEMPS TO PERSIST THROUGH THE WEEKEND...
WED/THU: SHORTWAVE ENERGY DIVING SOUTHEAST THROUGH THE PACIFIC NW
AND NORTHERN CA TONIGHT WILL AMPLIFY A LONGWAVE TROUGH OVER THE
INTERMOUNTAIN WEST AND DESERT SW ON TUE. CYCLOGENESIS WILL OCCUR
OVER THE CENTRAL PLAINS TUE NIGHT AS THE AMPLIFYING TROUGH
PROGRESSES ACROSS THE ROCKIES. AN ENERGETIC SFC CYCLONE WILL
ACCOMPANY THE UPPER TROUGH AS IT LIFTS NORTHEAST THROUGH THE
NORTHERN GREAT LAKES ON WED AND INTO CANADA WED NIGHT. DOWNSTREAM
ACROSS THE SOUTHEAST...SOUTHERLY LOW-LEVEL FLOW EMANATING FROM THE
GOMEX WILL STRENGTHEN IN CONCERT WITH STRENGTHENING SW FLOW ALOFT
AND TRANSPORT AN UNSEASONABLY MOIST AIRMASS INTO THE CAROLINAS (PWAT
VALUES > 1.50" AND SFC DEWPOINTS IN THE 60S TO NEAR 70F). GIVEN WELL
ABOVE NORMAL MOISTURE IN THE PRESENCE OF BROAD WARM ADVECTION AND
OCCASIONAL BOUTS OF DPVA ATTENDANT SMALL AMPLITUDE WAVES IN SW FLOW
ALOFT...EXPECT WIDESPREAD MODERATE TO OCCASIONALLY HEAVY RAIN WED
INTO WED NIGHT...WITH PRECIP AMOUNTS ~1.00" (LOCALLY HIGHER AMOUNTS
IN NW PIEDMONT). 1000-850 MB THICKNESSES SUPPORT ABOVE NORMAL
TEMPERATURES WED/THU. CLOUD COVER AND RAIN WILL HELP MODERATE TEMPS
ON WED (UPPER 60S TO LOWER 70S)...THOUGH LESS SO ON THU (MID/UPPER
70S) AS THE BEST WARM ADVECTION SHIFTS NORTH INTO THE MID-ATLANTIC
AND PRECIP CHANCES DIMINISH TO ISOLD/SCT DIURNAL SHOWERS. AT THIS
TIME DO NOT ANTICIPATE A CHANCE FOR THUNDER GIVEN MOIST-ADIABATIC
THERMAL PROFILES AND NO SIGNIFICANT FORCING...PARTICULARLY W/REGARD
TO DPVA/LAYER-LIFTING. DESPITE A LACK OF THUNDER...TIGHTENING OF THE
LOW-LEVEL HEIGHT/MSLP GRADIENT MAY YIELD GUSTY SOUTHWEST WINDS WED
AFTERNOON AND AGAIN ON THU...WITH WIND GUSTS UP TO ~45 MPH POSSIBLE
IN HEAVIER CONVECTION.
FRI-MON: THE COLD FRONT ASSOC/W THE UPPER LEVEL TROUGH AND ATTENDANT
SFC CYCLONE RAPIDLY PROGRESSING INTO CANADA WILL RAPIDLY WEAKEN AS
IT PROGRESSES EAST OF THE APPALACHIANS...BECOMING WSW-ENE ORIENTED
BEFORE STALLING IN VICINITY OF THE CAROLINA/SOUTHEAST COAST FRI.
LONG RANGE GUIDANCE DIVERGES SUBSTANTIALLY SAT-MON...APPARENTLY AS A
RESULT OF UNCERTAINTY IN THE EVOLUTION OF A POTENT UPPER LEVEL WAVE
(MOVING ASHORE THE NORTHERN CA/PACIFIC COAST FRI) EXPECTED TO
AMPLIFY INTO A CLOSED LOW OVER SOUTHERN CA AND THE DESERT SW THIS
WEEKEND BEFORE PROGRESSING SLOWLY EAST/NE INTO PORTIONS OF THE
CENTRAL CONUS BY EARLY NEXT WEEK. WITH THE ABOVE IN MIND...EXPECT
ABOVE NORMAL TEMPERATURES (TEMPERED BY BROKEN TO OVERCAST CLOUD
COVER) TO PERSIST OVER THE WEEKEND WITH VERY LITTLE POTENTIAL FOR
PRECIPITATION ASIDE FROM A FEW SPRINKLES OR AN OCCASIONAL SHOWER.
FORECAST UNCERTAINTY INCREASES DRAMATICALLY BY EARLY NEXT WEEK...
THOUGH PRECIP CHANCES SHOULD GENERALLY INCREASE FROM WEST-EAST
MON/TUE AS A COLD FRONT APPROACHES FROM THE WEST. -VINCENT
&&
.AVIATION /18Z TUESDAY THROUGH SATURDAY/...
AS OF 1235 PM MONDAY...
OTHER THAN SOME 2000 FT STRATUS LINGERING IN THE FOOTHILLS AND
WESTERN PIEDMONT...VFR CONDITIONS ARE EXPECTED TO CONTINUE ACROSS
CENTRAL NC THIS AFTERNOON. THE MVFR CEILINGS AT KGSO AND KINT MAY
BRIEFLY SCATTER OUT THROUGH 00Z...BUT SHOULD COME BACK IN TONIGHT AS
A MOISTURE CONTINUES TO INCREASE WITH WARM ADVECTION AHEAD OF A COLD
FRONT MOVING THROUGH THE MISSISSIPPI VALLEY REGION. AN UPPER TROUGH
LIFTING THROUGH THE MIDWEST TONIGHT WILL HELP TO SPREAD RAIN INTO
CENTRAL NC FROM THE SOUTHWEST AFTER 06Z...BRINGING IFR OR LIFR
CONDITIONS TO MOST...IF NOT ALL...TERMINALS LATE TONIGHT AND EARLY
TUESDAY. MODELS APPEAR TO BE A LITTLE SLOWER WITH THE ARRIVAL OF
THE RAIN AND LOW CLOUDS...WITH SOME INDICATIONS FROM KRDU TO THE
EAST MAY STAY VFR OR MVFR THROUGH 12Z. OVERALL...FORECAST
CONFIDENCE IS BELOW AVERAGE.
LONG TERM: A TUMULTUOUS PERIOD FOR AVIATION CONDITIONS AS A SLUG OF
MOISTURE MOVES OUT OF THE GULF OF MEXICO AND OVER THE SOUTHEASTERN
CONUS...WHICH COULD POTENTIALLY PRODUCE SEVERAL EXTENDED PERIODS OF
RAIN THROUGH THE WEEK AND INTO THE WEEKEND.
&&
.CLIMATE...
HERE ARE THE AREA RECORD MAXIMUMS AND HIGH MINIMUMS FOR DECEMBER 24TH
AND 25TH. RECORDS HAVE BEEN KEPT IN THE GREENSBORO AREA SINCE
1903... IN THE RALEIGH AREA SINCE 1887... AND IN THE FAYETTEVILLE
AREA SINCE 1899.
DEC 24: RECORD MAXIMUM HIGH MINIMUM
GREENSBORO 71 (1964) 52 (1904)
RALEIGH 75 (1931) 59 (1891)
FAYETTEVILLE 78 (1931) 66 (1990)
DEC 25: RECORD MAXIMUM HIGH MINIMUM
GREENSBORO 74 (1955) 58 (1932)
RALEIGH 75 (1955) 63 (1932)
FAYETTEVILLE 79 (1932) 68 (1932)
&&
.RAH WATCHES/WARNINGS/ADVISORIES... NONE.
&&
$$
SYNOPSIS...22
NEAR TERM...22
SHORT TERM...22
LONG TERM...VINCENT
AVIATION...22
CLIMATE...HARTFIELD/BLAES
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1235 PM EST MON DEC 21 2015
.SYNOPSIS... A SOUTHERLY FLOW OF WARMER AND MORE MOIST AIR WILL
DEVELOP TODAY AND PERSIST FOR MUCH OF THE WEEK. MEANWHILE...A COLD
FRONT WILL APPROACH THE AREA FROM THE WEST ON TUESDAY...THEN STALL
OVER THE REGION.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 930 AM MONDAY...
WATER IMAGERY THIS MORNING SHOWS A LONG FETCH OF MOISTURE FROM THE
PACIFIC ACROSS THE SOUTHERN US SOUTHWESTERLY DEEP LAYER FLOW SETS IN
FOR MUCH OF THE WEEK. REGIONAL 12Z RAOBS...NAMELY KFFC AND
KGSO...SHOW STEADY MOISTENING ALOFT THAT WILL KEEP SKIES CLOUDY
TODAY EVEN IF THE BLANKET OF STRATOCU OVER CENTRAL THIS MORNING
THINS OUT..WHICH RECENT RAP SOUNDINGS SUGGEST ACTUALLY WONT HAPPEN.
ADDITIONAL MOISTENING FROM WARM ADVECTION OVER THE WESTERN PIEDMONT
WILL RESULT IN SOME LOWER STRATUS BY THIS AFTERNOON. CURRENT FORECAST
HIGHS LOOKS TO AGREE WELL WITH INCREASING MID-CLOUD COVER...SO WILL
NUDGE THEM DOWN A COUPLE DEGREES GIVEN THE PERVASIVE 3-5K FT
CEILINGS...ESPECIALLY ACROSS THE WEST WHERE MULTIPLE LAYER OF CLOUDS
WILL STRONGLY INHIBIT HEATING. HIGHS SHOULD TOP IN THE LOWER 50S
WEST TO LOWER 60S EAST. -22
RAIN CHANCES WILL INCREASE THIS EVENING IN THE WEST AS SATURATION
BEGINS TO OCCUR AND PRECIPITABLE WATER VALUES CLIMB TO 1.25 INCHES.
ACCORDING TO 500 MB VORTICITY...THE FIRST REAL WAVE OF DYNAMICS
SHOULD HOLD OFF UNTIL BETWEEN 6 AND 12Z WHEN LOW LEVEL ISENTROPIC
LIFT REALLY BEGINS TO INCREASE SIGNIFICANTLY. NOT MORE THAN A FEW
HUNDREDTHS OF AN INCH OF QPF SHOULD ACCUMULATE BEFORE 12Z TUESDAY
BUT THIS INCREASE IN MOISTURE WILL REALLY LIMIT LOW TEMPERATURES
FROM DROPPING OVERNIGHT WITH LOWS IN THE TRIAD BOTTOMING OUT IN THE
UPPER 50S TO MID 50S IN THE SOUTHEAST.
&&
.SHORT TERM /TUESDAY AND TUESDAY NIGHT/...
AS OF 325 AM MONDAY...
RAIN CHANCES WILL OVERSPREAD THE ENTIRE CWA ON TUESDAY AS SEVERAL
SHORT WAVES CROSS THE AREA FROM THE SOUTH. CONVECTIVE ALLOWING
MODELS DIFFER A LITTLE BIT ON THE INTENSITY AND COVERAGE OF THE
RAINFALL...SO WOULD NOT BE SURPRISED TO SEE A FEW PERIODS OF HEAVIER
RAIN...FOLLOWED BY SOME LULLS...MOST LIKELY CORRESPONDING TO THE
DIFFERENT WAVES MOVING THROUGH THE AREA. QPF VALUES WILL MOST LIKELY
BE BETWEEN A HALF OF AN INCH AND AN INCH ON TUESDAY. EXPECT OVERCAST
SKIES FOR THE DURATION OF THE DAY BUT INCREASING WARM AIR ADVECTION
WILL BRING HIGH TEMPERATURES GENERALLY INTO THE 60S WITH LOW 60S IN
THE NW PIEDMONT AND UPPER 60S IN THE SOUTHEAST. BY TUESDAY NIGHT A
SECOND STRONGER WAVE OF PRECIPITATION WILL MOVE INTO WESTERN AREAS
OF THE CWA. DESPITE RAIN CHANCES ALL DAY...FLASH FLOOD GUIDANCE
REMAINS FAIRLY HIGH AND MMEFS INDICATES THAT MAIN STREAM RIVERS
SHOULD REMAIN BELOW FLOOD STAGE. LOW TEMPERATURES TUESDAY NIGHT WILL
ONLY FALL INTO THE MID 50S TO POTENTIALLY NEAR 60 DEGREES IN THE
SOUTHEAST. THIS IS A GOOD 25 DEGREES ABOVE NORMAL FOR THIS TIME OF
YEAR AND WONT EVEN BE THE WARMEST LOWS OF THE WEEK.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
AS OF 315 AM MONDAY...
WED THROUGH WED NIGHT: PERSISTENT UPPER LEVEL SOUTHWESTERLY FLOW
WILL CONTINUE...WITH SOUTHERLY FLOW AT THE SURFACE ADVECTING WARM
MOIST AIR INTO THE REGION. AN UPPER LEVEL SHORTWAVE WILL IMPINGE ON
THE CAROLINAS AS IT TRAVERSES THE EASTERN EDGE OF THE TROUGH OVER
THE MIDWEST...HELPING TO PROVIDE SUFFICIENT LIFT IN THE SATURATED
COLUMN TO PRODUCE SOME SIGNIFICANT RAINFALL. AS A RESULT...RAIN WILL
BE LIKELY DURING THE DAY AND INTO THE EARLY OVERNIGHT...WITH CHANCES
DECREASING SOME TOWARD DAYBREAK. THE SURFACE PRESSURE GRADIENT WILL
INCREASE DURING THE AFT/EVE...RESULTING IN INCREASING WIND SPEEDS.
HIGHS IN THE UPPER 60S TO MID 70S. LOWS IN THE LOW TO MID 60S.
THURSDAY AND THURSDAY NIGHT: STILL SOME DIFFERENCES IN THE MODELS
WITH RESPECT TO PRECIPITATION...THUS FORECAST UNCERTAINTY IS STILL
SOMEWHAT HIGH. HOWEVER...IT IS LOOKING MORE AND MORE LIKE THURSDAY
COULD BE RELATIVELY DRY...WITH JUST A SLIGHT CHANCE TO CHANCE OF
SOME RAIN. HIGHEST TEMPERATURES OF THE LONG TERM ARE STILL EXPECTED
ON THURSDAY AS THE SOUTHERLY WARM ADVECTION PEAKS. HIGHS IN THE LOW
70S NW TO UPPER 70S SE. LOWS UPPER 50S TO MID 60S.
FRIDAY ONWARD: THE APPROACHING FRONT WILL WEAKEN AS IT BECOMES MORE
WEST-EAST ORIENTED OVER VA/MD ON FRIDAY. THE MEDIUM RANGE MODELS
KEEP THE FRONT TO OUR NORTH...WITH UPPER LEVEL RIDGING FROM THE SE
PERSISTING OVER NC THROUGH THE WEEKEND. HOWEVER...DIFFERENCES
BETWEEN THE MODES WITH RESPECT TO THE PROGRESSION AND LOCATION OF
THE FRONT RESULT IN SIGNIFICANT DIFFERENCES IN PRECIP CHANCES. FOR
NOW WILL AT LEAST KEEP A SLIGHT CHANCE IN THROUGH THE EXTENDED UNTIL
BETTER AGREEMENT IS SEEN...HOWEVER THERE IS A DESCENT CHANCE MUCH OF
THIS PERIOD COULD BE DRY WITH JUST A FEW SHOWERS POSSIBLE. HIGHS
THROUGH THE PERIOD WILL GENERALLY RANGE FROM THE MID 60S TO MID 70S.
LOWS WILL GENERALLY BE IN THE 50S...WITH SOME LOW 60S POSSIBLE IN
THE SOUTH.
&&
.AVIATION /18Z TUESDAY THROUGH SATURDAY/...
AS OF 1235 PM MONDAY...
OTHER THAN SOME 2000 FT STRATUS LINGERING IN THE FOOTHILLS AND
WESTERN PIEDMONT...VFR CONDITIONS ARE EXPECTED TO CONTINUE ACROSS
CENTRAL NC THIS AFTERNOON. THE MVFR CEILINGS AT KGSO AND KINT MAY
BRIEFLY SCATTER OUT THROUGH 00Z...BUT SHOULD COME BACK IN TONIGHT AS
A MOISTURE CONTINUES TO INCREASE WITH WARM ADVECTION AHEAD OF A COLD
FRONT MOVING THROUGH THE MISSISSIPPI VALLEY REGION. AN UPPER TROUGH
LIFTING THROUGH THE MIDWEST TONIGHT WILL HELP TO SPREAD RAIN INTO
CENTRAL NC FROM THE SOUTHWEST AFTER 06Z...BRINGING IFR OR LIFR
CONDITIONS TO MOST...IF NOT ALL...TERMINALS LATE TONIGHT AND EARLY
TUESDAY. MODELS APPEAR TO BE A LITTLE SLOWER WITH THE ARRIVAL OF
THE RAIN AND LOW CLOUDS...WITH SOME INDICATIONS FROM KRDU TO THE
EAST MAY STAY VFR OR MVFR THROUGH 12Z. OVERALL...FORECAST
CONFIDENCE IS BELOW AVERAGE.
LONG TERM: A TUMULTUOUS PERIOD FOR AVIATION CONDITIONS AS A SLUG OF
MOISTURE MOVES OUT OF THE GULF OF MEXICO AND OVER THE SOUTHEASTERN
CONUS...WHICH COULD POTENTIALLY PRODUCE SEVERAL EXTENDED PERIODS OF
RAIN THROUGH THE WEEK AND INTO THE WEEKEND.
&&
.CLIMATE...
HERE ARE THE AREA RECORD MAXIMUMS AND HIGH MINIMUMS FOR DECEMBER 24TH
AND 25TH. RECORDS HAVE BEEN KEPT IN THE GREENSBORO AREA SINCE
1903... IN THE RALEIGH AREA SINCE 1887... AND IN THE FAYETTEVILLE
AREA SINCE 1899.
DEC 24: RECORD MAXIMUM HIGH MINIMUM
GREENSBORO 71 (1964) 52 (1904)
RALEIGH 75 (1931) 59 (1891)
FAYETTEVILLE 78 (1931) 66 (1990)
DEC 25: RECORD MAXIMUM HIGH MINIMUM
GREENSBORO 74 (1955) 58 (1932)
RALEIGH 75 (1955) 63 (1932)
FAYETTEVILLE 79 (1932) 68 (1932)
&&
.RAH WATCHES/WARNINGS/ADVISORIES... NONE.
&&
$$
SYNOPSIS...22
NEAR TERM...ELLIS/22
SHORT TERM...ELLIS
LONG TERM...KC
AVIATION...22
CLIMATE...HARTFIELD/BLAES
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1055 AM EST MON DEC 21 2015
.SYNOPSIS...A SOUTHERLY FLOW OF WARMER AND MORE MOIST AIR WILL
DEVELOP TODAY AND PERSIST FOR MUCH OF THE WEEK. MEANWHILE...A COLD
FRONT WILL APPROACH THE AREA FROM THE WEST ON TUESDAY...THEN STALL
OVER THE REGION.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 930 AM MONDAY...
WATER IMAGERY THIS MORNING SHOWS A LONG FETCH OF MOISTURE FROM THE
PACIFIC ACROSS THE SOUTHERN US SOUTHWESTERLY DEEP LAYER FLOW SETS IN
FOR MUCH OF THE WEEK. REGIONAL 12Z RAOBS...NAMELY KFFC AND
KGSO...SHOW STEADY MOISTENING ALOFT THAT WILL KEEP SKIES CLOUDY
TODAY EVEN IF THE BLANKET OF STRATOCU OVER CENTRAL THIS MORNING
THINS OUT..WHICH RECENT RAP SOUNDINGS SUGGEST ACTUALLY WONT HAPPEN.
ADDITIONAL MOISTENING FROM WARM ADVECTION OVER THE WESTERN PIEDMONT
WILL RESULT IN SOME LOWER STRATUS BY THIS AFTERNOON. CURRENT FORECAST
HIGHS LOOKS TO AGREE WELL WITH INCREASING MID-CLOUD COVER...SO WILL
NUDGE THEM DOWN A COUPLE DEGREES GIVEN THE PERVASIVE 3-5K FT
CEILINGS...ESPECIALLY ACROSS THE WEST WHERE MULTIPLE LAYER OF CLOUDS
WILL STRONGLY INHIBIT HEATING. HIGHS SHOULD TOP IN THE LOWER 50S
WEST TO LOWER 60S EAST. -22
RAIN CHANCES WILL INCREASE THIS EVENING IN THE WEST AS SATURATION
BEGINS TO OCCUR AND PRECIPITABLE WATER VALUES CLIMB TO 1.25 INCHES.
ACCORDING TO 500 MB VORTICITY...THE FIRST REAL WAVE OF DYNAMICS
SHOULD HOLD OFF UNTIL BETWEEN 6 AND 12Z WHEN LOW LEVEL ISENTROPIC
LIFT REALLY BEGINS TO INCREASE SIGNIFICANTLY. NOT MORE THAN A FEW
HUNDREDTHS OF AN INCH OF QPF SHOULD ACCUMULATE BEFORE 12Z TUESDAY
BUT THIS INCREASE IN MOISTURE WILL REALLY LIMIT LOW TEMPERATURES
FROM DROPPING OVERNIGHT WITH LOWS IN THE TRIAD BOTTOMING OUT IN THE
UPPER 50S TO MID 50S IN THE SOUTHEAST.
&&
.SHORT TERM /TUESDAY AND TUESDAY NIGHT/...
AS OF 325 AM MONDAY...
RAIN CHANCES WILL OVERSPREAD THE ENTIRE CWA ON TUESDAY AS SEVERAL
SHORT WAVES CROSS THE AREA FROM THE SOUTH. CONVECTIVE ALLOWING
MODELS DIFFER A LITTLE BIT ON THE INTENSITY AND COVERAGE OF THE
RAINFALL...SO WOULD NOT BE SURPRISED TO SEE A FEW PERIODS OF HEAVIER
RAIN...FOLLOWED BY SOME LULLS...MOST LIKELY CORRESPONDING TO THE
DIFFERENT WAVES MOVING THROUGH THE AREA. QPF VALUES WILL MOST LIKELY
BE BETWEEN A HALF OF AN INCH AND AN INCH ON TUESDAY. EXPECT OVERCAST
SKIES FOR THE DURATION OF THE DAY BUT INCREASING WARM AIR ADVECTION
WILL BRING HIGH TEMPERATURES GENERALLY INTO THE 60S WITH LOW 60S IN
THE NW PIEDMONT AND UPPER 60S IN THE SOUTHEAST. BY TUESDAY NIGHT A
SECOND STRONGER WAVE OF PRECIPITATION WILL MOVE INTO WESTERN AREAS
OF THE CWA. DESPITE RAIN CHANCES ALL DAY...FLASH FLOOD GUIDANCE
REMAINS FAIRLY HIGH AND MMEFS INDICATES THAT MAIN STREAM RIVERS
SHOULD REMAIN BELOW FLOOD STAGE. LOW TEMPERATURES TUESDAY NIGHT WILL
ONLY FALL INTO THE MID 50S TO POTENTIALLY NEAR 60 DEGREES IN THE
SOUTHEAST. THIS IS A GOOD 25 DEGREES ABOVE NORMAL FOR THIS TIME OF
YEAR AND WONT EVEN BE THE WARMEST LOWS OF THE WEEK.
&&
.LONG TERM /WEDNESDAY THROUGH TUESDAY/...
AS OF 1200 PM MONDAY...
...WIDESPREAD RAIN WED INTO WED NIGHT...
...ABOVE NORMAL TEMPS TO PERSIST THROUGH THE WEEKEND...
WED/THU: SHORTWAVE ENERGY DIVING SOUTHEAST THROUGH THE PACIFIC NW
AND NORTHERN CA TONIGHT WILL AMPLIFY A LONGWAVE TROUGH OVER THE
INTERMOUNTAIN WEST AND DESERT SW ON TUE. CYCLOGENESIS WILL OCCUR
OVER THE CENTRAL PLAINS TUE NIGHT AS THE AMPLIFYING TROUGH
PROGRESSES ACROSS THE ROCKIES. AN ENERGETIC SFC CYCLONE WILL
ACCOMPANY THE UPPER TROUGH AS IT LIFTS NORTHEAST THROUGH THE
NORTHERN GREAT LAKES ON WED AND INTO CANADA WED NIGHT. DOWNSTREAM
ACROSS THE SOUTHEAST...SOUTHERLY LOW-LEVEL FLOW EMANATING FROM THE
GOMEX WILL STRENGTHEN IN CONCERT WITH STRENGTHENING SW FLOW ALOFT
AND TRANSPORT AN UNSEASONABLY MOIST AIRMASS INTO THE CAROLINAS (PWAT
VALUES > 1.50" AND SFC DEWPOINTS IN THE 60S TO NEAR 70F). GIVEN WELL
ABOVE NORMAL MOISTURE IN THE PRESENCE OF BROAD WARM ADVECTION AND
OCCASIONAL BOUTS OF DPVA ATTENDANT SMALL AMPLITUDE WAVES IN SW FLOW
ALOFT...EXPECT WIDESPREAD MODERATE TO OCCASIONALLY HEAVY RAIN WED
INTO WED NIGHT...WITH PRECIP AMOUNTS ~1.00" (LOCALLY HIGHER AMOUNTS
IN NW PIEDMONT). 1000-850 MB THICKNESSES SUPPORT ABOVE NORMAL
TEMPERATURES WED/THU. CLOUD COVER AND RAIN WILL HELP MODERATE TEMPS
ON WED (UPPER 60S TO LOWER 70S)...THOUGH LESS SO ON THU (MID/UPPER
70S) AS THE BEST WARM ADVECTION SHIFTS NORTH INTO THE MID-ATLANTIC
AND PRECIP CHANCES DIMINISH TO ISOLD/SCT DIURNAL SHOWERS. AT THIS
TIME DO NOT ANTICIPATE A CHANCE FOR THUNDER GIVEN MOIST-ADIABATIC
THERMAL PROFILES AND NO SIGNIFICANT FORCING...PARTICULARLY W/REGARD
TO DPVA/LAYER-LIFTING. DESPITE A LACK OF THUNDER...TIGHTENING OF THE
LOW-LEVEL HEIGHT/MSLP GRADIENT MAY YIELD GUSTY SOUTHWEST WINDS WED
AFTERNOON AND AGAIN ON THU...WITH WIND GUSTS UP TO ~45 MPH POSSIBLE
IN HEAVIER CONVECTION.
FRI-MON: THE COLD FRONT ASSOC/W THE UPPER LEVEL TROUGH AND ATTENDANT
SFC CYCLONE RAPIDLY PROGRESSING INTO CANADA WILL RAPIDLY WEAKEN AS
IT PROGRESSES EAST OF THE APPALACHIANS...BECOMING WSW-ENE ORIENTED
BEFORE STALLING IN VICINITY OF THE CAROLINA/SOUTHEAST COAST FRI.
LONG RANGE GUIDANCE DIVERGES SUBSTANTIALLY SAT-MON...APPARENTLY AS A
RESULT OF UNCERTAINTY IN THE EVOLUTION OF A POTENT UPPER LEVEL WAVE
(MOVING ASHORE THE NORTHERN CA/PACIFIC COAST FRI) EXPECTED TO
AMPLIFY INTO A CLOSED LOW OVER SOUTHERN CA AND THE DESERT SW THIS
WEEKEND BEFORE PROGRESSING SLOWLY EAST/NE INTO PORTIONS OF THE
CENTRAL CONUS BY EARLY NEXT WEEK. WITH THE ABOVE IN MIND...EXPECT
ABOVE NORMAL TEMPERATURES (TEMPERED BY BROKEN TO OVERCAST CLOUD
COVER) TO PERSIST OVER THE WEEKEND WITH VERY LITTLE POTENTIAL FOR
PRECIPITATION ASIDE FROM A FEW SPRINKLES OR AN OCCASIONAL SHOWER.
FORECAST UNCERTAINTY INCREASES DRAMATICALLY BY EARLY NEXT WEEK...
THOUGH PRECIP CHANCES SHOULD GENERALLY INCREASE FROM WEST-EAST
MON/TUE AS A COLD FRONT APPROACHES FROM THE WEST. -VINCENT
&&
.AVIATION /12Z TUESDAY THROUGH FRIDAY/...
AS OF 645 AM MONDAY...
24 HOUR TAF PERIOD: MVFR CONDITIONS HAVE MOVED INTO THE TRIAD AT
THIS TIME BUT EASTERN SITES COULD POTENTIALLY REMAIN VFR THROUGH
MOST OF THE TAF PERIOD WITH MVFR CEILINGS CREEPING INTO THE EAST
BETWEEN 00Z AND 06Z TUESDAY. RAIN CHANCES WILL ALSO AS THE TAF
PERIOD GOES ON WITH SOME LIGHT SPRINKLES SHOWING UP ON HIGH
RESOLUTION MODELS IN THE EAST BEFORE MORE SUBSTANTIAL RAIN CHANCES
INCREASE FROM WEST TO EAST EARLY TUESDAY MORNING.
LONG TERM: A TUMULTUOUS PERIOD FOR AVIATION CONDITIONS AS A SLUG OF
MOISTURE MOVES OUT OF THE GULF OF MEXICO AND OVER THE SOUTHEASTERN
CONUS...WHICH COULD POTENTIALLY PRODUCE SEVERAL EXTENDED PERIODS OF
RAIN THROUGH THE WEEK AND INTO THE WEEKEND.
&&
.CLIMATE...
HERE ARE THE AREA RECORD MAXIMUMS AND HIGH MINIMUMS FOR DECEMBER 24TH
AND 25TH. RECORDS HAVE BEEN KEPT IN THE GREENSBORO AREA SINCE
1903... IN THE RALEIGH AREA SINCE 1887... AND IN THE FAYETTEVILLE
AREA SINCE 1899.
DEC 24: RECORD MAXIMUM HIGH MINIMUM
GREENSBORO 71 (1964) 52 (1904)
RALEIGH 75 (1931) 59 (1891)
FAYETTEVILLE 78 (1931) 66 (1990)
DEC 25: RECORD MAXIMUM HIGH MINIMUM
GREENSBORO 74 (1955) 58 (1932)
RALEIGH 75 (1955) 63 (1932)
FAYETTEVILLE 79 (1932) 68 (1932)
&&
.RAH WATCHES/WARNINGS/ADVISORIES... NONE.
&&
$$
SYNOPSIS...22
NEAR TERM...ELLIS/22
SHORT TERM...ELLIS
LONG TERM...VINCENT
AVIATION...ELLIS
CLIMATE...HARTFIELD/BLAES
AREA FORECAST DISCUSSION
NWS RALEIGH NC
930 AM EST MON DEC 21 2015
.SYNOPSIS... A SOUTHERLY FLOW OF WARMER AND MORE MOIST AIR WILL
DEVELOP TODAY AND PERSIST FOR MUCH OF THE WEEK. MEANWHILE...A COLD
FRONT WILL APPROACH THE AREA FROM THE WEST ON TUESDAY...THEN STALL
OVER THE REGION.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 930 AM MONDAY...
WATER IMAGERY THIS MORNING SHOWS A LONG FETCH OF MOISTURE FROM THE
PACIFIC ACROSS THE SOUTHERN US SOUTHWESTERLY DEEP LAYER FLOW SETS IN
FOR MUCH OF THE WEEK. REGIONAL 12Z RAOBS...NAMELY KFFC AND
KGSO...SHOW STEADY MOISTENING ALOFT THAT WILL KEEP SKIES CLOUDY
TODAY EVEN IF THE BLANKET OF STRATOCU OVER CENTRAL THIS MORNING
THINS OUT..WHICH RECENT RAP SOUNDINGS SUGGEST ACTUALLY WONT HAPPEN.
ADDITIONAL MOISTENING FROM WARM ADVECTION OVER THE WESTERN PIEDMONT
WILL RESULT IN SOME LOWER STRATUS BY THIS AFTERNOON. CURRENT FORECAST
HIGHS LOOKS TO AGREE WELL WITH INCREASING MID-CLOUD COVER...SO WILL
NUDGE THEM DOWN A COUPLE DEGREES GIVEN THE PERVASIVE 3-5K FT
CEILINGS...ESPECIALLY ACROSS THE WEST WHERE MULTIPLE LAYER OF CLOUDS
WILL STRONGLY INHIBIT HEATING. HIGHS SHOULD TOP IN THE LOWER 50S
WEST TO LOWER 60S EAST. -22
RAIN CHANCES WILL INCREASE THIS EVENING IN THE WEST AS SATURATION
BEGINS TO OCCUR AND PRECIPITABLE WATER VALUES CLIMB TO 1.25 INCHES.
ACCORDING TO 500 MB VORTICITY...THE FIRST REAL WAVE OF DYNAMICS
SHOULD HOLD OFF UNTIL BETWEEN 6 AND 12Z WHEN LOW LEVEL ISENTROPIC
LIFT REALLY BEGINS TO INCREASE SIGNIFICANTLY. NOT MORE THAN A FEW
HUNDREDTHS OF AN INCH OF QPF SHOULD ACCUMULATE BEFORE 12Z TUESDAY
BUT THIS INCREASE IN MOISTURE WILL REALLY LIMIT LOW TEMPERATURES
FROM DROPPING OVERNIGHT WITH LOWS IN THE TRIAD BOTTOMING OUT IN THE
UPPER 50S TO MID 50S IN THE SOUTHEAST.
&&
.SHORT TERM /TUESDAY AND TUESDAY NIGHT/...
AS OF 325 AM MONDAY...
RAIN CHANCES WILL OVERSPREAD THE ENTIRE CWA ON TUESDAY AS SEVERAL
SHORT WAVES CROSS THE AREA FROM THE SOUTH. CONVECTIVE ALLOWING
MODELS DIFFER A LITTLE BIT ON THE INTENSITY AND COVERAGE OF THE
RAINFALL...SO WOULD NOT BE SURPRISED TO SEE A FEW PERIODS OF HEAVIER
RAIN...FOLLOWED BY SOME LULLS...MOST LIKELY CORRESPONDING TO THE
DIFFERENT WAVES MOVING THROUGH THE AREA. QPF VALUES WILL MOST LIKELY
BE BETWEEN A HALF OF AN INCH AND AN INCH ON TUESDAY. EXPECT OVERCAST
SKIES FOR THE DURATION OF THE DAY BUT INCREASING WARM AIR ADVECTION
WILL BRING HIGH TEMPERATURES GENERALLY INTO THE 60S WITH LOW 60S IN
THE NW PIEDMONT AND UPPER 60S IN THE SOUTHEAST. BY TUESDAY NIGHT A
SECOND STRONGER WAVE OF PRECIPITATION WILL MOVE INTO WESTERN AREAS
OF THE CWA. DESPITE RAIN CHANCES ALL DAY...FLASH FLOOD GUIDANCE
REMAINS FAIRLY HIGH AND MMEFS INDICATES THAT MAIN STREAM RIVERS
SHOULD REMAIN BELOW FLOOD STAGE. LOW TEMPERATURES TUESDAY NIGHT WILL
ONLY FALL INTO THE MID 50S TO POTENTIALLY NEAR 60 DEGREES IN THE
SOUTHEAST. THIS IS A GOOD 25 DEGREES ABOVE NORMAL FOR THIS TIME OF
YEAR AND WONT EVEN BE THE WARMEST LOWS OF THE WEEK.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
AS OF 315 AM MONDAY...
WED THROUGH WED NIGHT: PERSISTENT UPPER LEVEL SOUTHWESTERLY FLOW
WILL CONTINUE...WITH SOUTHERLY FLOW AT THE SURFACE ADVECTING WARM
MOIST AIR INTO THE REGION. AN UPPER LEVEL SHORTWAVE WILL IMPINGE ON
THE CAROLINAS AS IT TRAVERSES THE EASTERN EDGE OF THE TROUGH OVER
THE MIDWEST...HELPING TO PROVIDE SUFFICIENT LIFT IN THE SATURATED
COLUMN TO PRODUCE SOME SIGNIFICANT RAINFALL. AS A RESULT...RAIN WILL
BE LIKELY DURING THE DAY AND INTO THE EARLY OVERNIGHT...WITH CHANCES
DECREASING SOME TOWARD DAYBREAK. THE SURFACE PRESSURE GRADIENT WILL
INCREASE DURING THE AFT/EVE...RESULTING IN INCREASING WIND SPEEDS.
HIGHS IN THE UPPER 60S TO MID 70S. LOWS IN THE LOW TO MID 60S.
THURSDAY AND THURSDAY NIGHT: STILL SOME DIFFERENCES IN THE MODELS
WITH RESPECT TO PRECIPITATION...THUS FORECAST UNCERTAINTY IS STILL
SOMEWHAT HIGH. HOWEVER...IT IS LOOKING MORE AND MORE LIKE THURSDAY
COULD BE RELATIVELY DRY...WITH JUST A SLIGHT CHANCE TO CHANCE OF
SOME RAIN. HIGHEST TEMPERATURES OF THE LONG TERM ARE STILL EXPECTED
ON THURSDAY AS THE SOUTHERLY WARM ADVECTION PEAKS. HIGHS IN THE LOW
70S NW TO UPPER 70S SE. LOWS UPPER 50S TO MID 60S.
FRIDAY ONWARD: THE APPROACHING FRONT WILL WEAKEN AS IT BECOMES MORE
WEST-EAST ORIENTED OVER VA/MD ON FRIDAY. THE MEDIUM RANGE MODELS
KEEP THE FRONT TO OUR NORTH...WITH UPPER LEVEL RIDGING FROM THE SE
PERSISTING OVER NC THROUGH THE WEEKEND. HOWEVER...DIFFERENCES
BETWEEN THE MODES WITH RESPECT TO THE PROGRESSION AND LOCATION OF
THE FRONT RESULT IN SIGNIFICANT DIFFERENCES IN PRECIP CHANCES. FOR
NOW WILL AT LEAST KEEP A SLIGHT CHANCE IN THROUGH THE EXTENDED UNTIL
BETTER AGREEMENT IS SEEN...HOWEVER THERE IS A DESCENT CHANCE MUCH OF
THIS PERIOD COULD BE DRY WITH JUST A FEW SHOWERS POSSIBLE. HIGHS
THROUGH THE PERIOD WILL GENERALLY RANGE FROM THE MID 60S TO MID 70S.
LOWS WILL GENERALLY BE IN THE 50S...WITH SOME LOW 60S POSSIBLE IN
THE SOUTH.
&&
.AVIATION /12Z TUESDAY THROUGH FRIDAY/...
AS OF 645 AM MONDAY...
24 HOUR TAF PERIOD: MVFR CONDITIONS HAVE MOVED INTO THE TRIAD AT
THIS TIME BUT EASTERN SITES COULD POTENTIALLY REMAIN VFR THROUGH
MOST OF THE TAF PERIOD WITH MVFR CEILINGS CREEPING INTO THE EAST
BETWEEN 00Z AND 06Z TUESDAY. RAIN CHANCES WILL ALSO AS THE TAF
PERIOD GOES ON WITH SOME LIGHT SPRINKLES SHOWING UP ON HIGH
RESOLUTION MODELS IN THE EAST BEFORE MORE SUBSTANTIAL RAIN CHANCES
INCREASE FROM WEST TO EAST EARLY TUESDAY MORNING.
LONG TERM: A TUMULTUOUS PERIOD FOR AVIATION CONDITIONS AS A SLUG OF
MOISTURE MOVES OUT OF THE GULF OF MEXICO AND OVER THE SOUTHEASTERN
CONUS...WHICH COULD POTENTIALLY PRODUCE SEVERAL EXTENDED PERIODS OF
RAIN THROUGH THE WEEK AND INTO THE WEEKEND.
&&
.CLIMATE...
HERE ARE THE AREA RECORD MAXIMUMS AND HIGH MINIMUMS FOR DECEMBER 24TH
AND 25TH. RECORDS HAVE BEEN KEPT IN THE GREENSBORO AREA SINCE
1903... IN THE RALEIGH AREA SINCE 1887... AND IN THE FAYETTEVILLE
AREA SINCE 1899.
DEC 24: RECORD MAXIMUM HIGH MINIMUM
GREENSBORO 71 (1964) 52 (1904)
RALEIGH 75 (1931) 59 (1891)
FAYETTEVILLE 78 (1931) 66 (1990)
DEC 25: RECORD MAXIMUM HIGH MINIMUM
GREENSBORO 74 (1955) 58 (1932)
RALEIGH 75 (1955) 63 (1932)
FAYETTEVILLE 79 (1932) 68 (1932)
&&
.RAH WATCHES/WARNINGS/ADVISORIES... NONE.
&&
$$
SYNOPSIS...22
NEAR TERM...ELLIS/22
SHORT TERM...ELLIS
LONG TERM...KC
AVIATION...ELLIS
CLIMATE...HARTFIELD/BLAES
AREA FORECAST DISCUSSION
NWS BISMARCK ND
957 PM CST TUE DEC 22 2015
.UPDATE...
ISSUED AT 934 PM CST TUE DEC 22 2015
...WILL CONTINUE THE WINTER STORM WARNING FAR NORTH CENTRAL...
SURFACE LOW PRESSURE OVER EAST CENTRAL NORTH DAKOTA WITH UPPER LOW
OVER SOUTHWEST MANITOBA. WARM SECTOR PRECIPITATION HAS PRETTY MUCH
LIFTED NORTH THROUGH NORTHERN MINNESOTA WITH MAINLY WRAP AROUND
MOISTURE CAUGHT IN THE DEFORMATION ZONE THAT STRETCHES BACK WEST
ACROSS NORTHERN NORTH DAKOTA AND INTO NORTHEAST MONTANA. LIGHT
SNOW STILL CONTINUING OVER NORTHERN PORTIONS OF PIERCE AND MCHENRY
COUNTY AND PRETTY MUCH MOST OF ROLETTE AND BOTTINEAU COUNTIES.
LATEST MESOSCALE MODELS CONTINUE TO INDICATE THIS AREA OF
PRECIPITATION REMAINING OVER THE WARNING AREA THROUGH AT LEAST 06
UTC AND THEN DISSIPATING...LIFTING NORTH THEREAFTER...WHILE WEAK
SHORTWAVE ENERGY PUSHES FROM NORTHEAST MONTANA INTO WESTERN NORTH
DAKOTA. HAVE UPDATE POPS TO KEEP CATEGORICAL POPS ACROSS THE
NORTH THROUGH 06 UTC...AND THEN SLOWLY TAPERING TO CHANCE POPS
AROUND 12Z. A DEEP DENDRITIC GROWTH LAYER REMAINS ACROSS NORTHERN
NORTH DAKOTA...AND OCCASIONAL BANDS OF HIGHER REFLECTIVITIES
CONTINUE TO DEVELOP ACROSS THE WARNING AREA. THEREFORE WILL
CONTINUE THE WARNING FOR NOW AND WILL TONE DOWN THE ADDITIONAL
SNOWFALL AMOUNTS. MANY AREAS WITHIN THE WARNING AREA HAD RECEIVED
4 TO 7 INCHES THROUGH LATE AFTERNOON...SO COULD SEE SOME MORE
REPORTS OF 6-8 INCHES WHEN MORNING REPORTS COME IN THURSDAY.
WARNING DOES EXPIRE AT 12 UTC BUT THE OVERNIGHT SHIFT CAN CANCEL
EARLY IF SNOW ENDS.
BACK IN NORTHWEST NORTH DAKOTA...LITTLE IF ANY SNOW FELL DURING
THE DAY WEDNESDAY...BUT WITH SNOW THIS EVENING...CONINUING INTO
THURSDAY MORNING...WOULD EXPECT A FEW REPORTS OF 1-2 INCHES.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 253 PM CST TUE DEC 22 2015
HEAVY SNOW NORTH CENTRAL THROUGH EARLY THIS EVENING HIGHLIGHTS THE
SHORT TERM FORECAST.
AS OF 2130 UTC...A SECONDARY SHORTWAVE EVIDENT ON WATER VAPOR HAS
PROPAGATED NORTHEAST OUT OF NORTH CENTRAL SOUTH DAKOTA INTO SOUTH
CENTRAL NORTH DAKOTA...AS REFLECTED IN THE INTENSIFICATION OF
SNOWFALL ACROSS SOUTH CENTRAL NORTH DAKOTA OVER THE PAST ONE TO
TWO HOURS. THIS WAVE WILL CONTINUE TO PROPAGATE NORTHEAST AND
INTERACT WITH THE TROWAL ACROSS NORTH CENTRAL AND NORTHEAST NORTH
DAKOTA TO CONTINUE TO SUPPORT HEAVY SNOWFALL THROUGH EARLY THIS
EVENING. THE 17-20 UTC HRRR AND RAP ITERATIONS HAVE HANDLED THE
MESOSCALE BANDING OF SNOWFALL WELL THROUGH THE AFTERNOON AND WILL
FOLLOW THEIR SOLUTIONS THROUGH THE EVENING...BLENDED TO THE 12 UTC
GLOBAL SUITE LATE TONIGHT INTO WEDNESDAY MORNING. OVERALL...STORM
TOTAL SNOWFALL ACCUMULATIONS OF 6 TO 8 INCHES REMAIN UNCHANGED FOR
THE TOWNER...RUGBY...BOTTINEAU AND ROLETTE AREAS...WITH LOCALLY
HIGHER AMOUNTS. ELSEWHERE FOR TONIGHT INTO WEDNESDAY
MORNING...LIGHT SNOW IS EXPECTED. THIS IS IN ASSOCIATION WITH THE
WEAKENING TROWAL AND A WAVE CURRENTLY ACROSS NORTH CENTRAL
MONTANA THAT WILL PROPAGATE SOUTHEAST. ADDITIONAL SNOWFALL
ACCUMULATIONS OF AROUND ONE...TO POSSIBLY TWO INCHES ACROSS THE
WEST INTO THE SOUTH CENTRAL ARE FORECAST.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 253 PM CST TUE DEC 22 2015
COOLING TEMPERATURES INTO THE WEEKEND HIGHLIGHT THE EXTENDED
FORECAST.
THE 12 UTC DETERMINISTIC AND ENSEMBLE SUITES ARE IN AGREEMENT ON
A BROAD...UPPER LEVEL WESTERN AND CENTRAL CONUS TROUGH TO BEGIN
THE PERIOD TO POSSIBLY TRANSITION TO SPLIT FLOW BY THE
WEEKEND...POTENTIALLY PLACING THE NORTHERN PLAINS IN NORTHWEST
FLOW ALOFT WITH THE NORTHERN STREAM. THIS SUPPORTS A POSSIBLE COOL
DOWN INTO THE WEEKEND. OVERALL...THE CHRISTMAS TRAVEL OUTLOOK
LOOKS GOOD WITH RATHER QUIET WEATHER.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 934 PM CST TUE DEC 22 2015
MVFR TO OCCASIONAL IFR CONDITIONS ARE EXPECTED ACROSS WESTERN AND
CENTRAL NORTH DAKOTA TONIGHT AND THROUGH MUCH OF THE DAY ON
THURSDAY. LIGHT WEST FLOW TONIGHT WILL TURN NORTH TO NORTHWEST
AND INCREASE TO UP TO 15 MPH ON THURSDAY.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL 6 AM CST WEDNESDAY FOR NDZ004-005-012-
013.
&&
$$
UPDATE...TWH
SHORT TERM...AYD
LONG TERM...AYD
AVIATION...TWH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
249 PM CST MON DEC 21 2015
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 215 PM CST MON DEC 21 2015
FOG TONIGHT AND ACCUMULATING SNOW TUESDAY HIGHLIGHT THE SHORT TERM
FORECAST.
THE 15-19 UTC HRRR ITERATIONS AND THE 12 UTC NAM NEST ONCE AGAIN
TONIGHT DEPICT FOG DEVELOPMENT WITHIN THEIR RESPECTIVE VISIBILITY
FIELDS. THESE FORECASTS HAVE PERFORMED WELL THE PAST WEEK IN
SIGNALING FOG...AND WILL FOLLOW THEIR SOLUTIONS WHICH SUGGEST FOG
GENERALLY ALONG AND EAST OF HIGHWAY 83 TONIGHT INTO EARLY TUESDAY
MORNING BEFORE THE SNOWFALL. A DENSE FOG ADVISORY MAY BE
POSSIBLE.
FOR TUESDAY...THE 12 UTC AND INCOMING 18 UTC DETERMINISTIC AND
ENSEMBLE SUITES ARE IN AGREEMENT ON A WAVE EJECTING NORTHEAST OUT
OF WYOMING...DEEPENING AND POTENTIALLY CLOSING OFF AS IT
PROPAGATES ACROSS NORTH DAKOTA. STRONG FRONTOGENETIC FORCING AND
VERTICAL MOTION IN THE DENDRITIC GROWTH LAYER ARE EXPECTED ALONG
AND NORTH OF THE 700 MB LOW TRACK FROM SOUTHWEST THROUGH NORTHEAST
NORTH DAKOTA TO SUPPORT MESOSCALE BANDING OF SNOW. THE GREATEST
SNOWFALL AMOUNTS OF 3 TO 5 INCHES ARE FORECAST ACROSS THE FAR
NORTH CENTRAL AND TURTLE MOUNTAINS WHERE SNOWFALL DURATION WILL BE
THE LONGEST IN ASSOCIATION WITH THE DEVELOPING TROWAL. THUS...HAVE
ISSUED A WINTER WEATHER ADVISORY FOR THESE AREAS. FOR NOW...THE
LACK OF STRONG ELEVATED INSTABILITY IS EXPECTED TO KEEP SNOWFALL
AMOUNTS BELOW WARNING LEVELS. HOWEVER...THIS WILL HAVE TO BE
CLOSELY MONITORED IN THE MODEL SOLUTIONS OVER THE NEXT 12 HOURS.
ELSEWHERE...WIDESPREAD ONE TO THREE INCH SNOWFALL AMOUNTS ARE
EXPECTED.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 215 PM CST MON DEC 21 2015
SURFACE LOW AND ASSOCIATED MID/UPPER LEVEL TROUGH WILL EXIT THE
TURTLE MOUNTAINS AND SHIFT INTO SOUTHERN ONTARIO BY 12Z WEDNESDAY.
SNOW WILL GRADUALLY DIMINISH AND END TUESDAY NIGHT WITH A COLD
POCKET/THERMAL TROUGH LINGERING THROUGH WEDNESDAY. THIS WILL RESULT
IN PLENTY OF CLOUDS AND POSSIBLE FLURRIES WEDNESDAY. ANOTHER WEAK
SHORTWAVE IS EXPECTED THURSDAY AFTERNOON/EVENING...BUT ANY
PRECIPITATION THREAT IS VERY MINIMAL. A SPLIT FLOW DEVELOPS FOR
THE REST OF THE EXTENDED PERIOD AS AN UPPER TROUGH/LOW IS CARVED
OUT IN THE SOUTHWEST. NORTH DAKOTA FALLS UNDER A SOUTHWEST FLOW
ALOFT CHRISTMAS DAY/FRIDAY...WITH A DEFORMATION ZONE EVOLVING
ACROSS SOUTHERN NORTH DAKOTA FRIDAY NIGHT INTO SATURDAY MORNING.
CHRISTMAS DAY REMAINS DRY WITH MOISTURE ADVECTION INCREASING
FRIDAY EVENING FAR SOUTH. THIS IS IN RESPONSE TO AN INITIAL
MID/UPPER LEVEL LOW EJECTING FROM THE SOUTHWEST UPPER TROUGH WILL
SLIDE ACROSS SOUTH DAKOTA DURING THE ABOVE TIME. WILL CONTINUE TO
WATCH THE TRACK BUT AS OF NOW SOME LIGHT SNOW IS EXPECTED SOUTH OF
I-94 DURING THIS TIME. THIS SHORTWAVE DEPARTS SATURDAY NIGHT WITH
DRY WEATHER UNTIL AT LEAST MONDAY. HIGHS WILL REMAINING IN THE 20S
WED/THU...THEN COLDER AIR WILL BE DRAWN INTO THE APPROACHING
SOUTHWEST SYSTEM WITH WINDS BECOMING NORTH TO NORTHEAST FRI/SAT.
AS THE SYSTEM DEPARTS AND WINDS BECOME SOUTHWEST...HIGHS WILL ONCE
AGAIN REBOUND INTO THE 20S SUNDAY AND MONDAY. OVERNIGHT LOWS WILL
BE COLDEST FRIDAY MORNING THROUGH SUNDAY MORNING WITH LOWS 5 BELOW
ZERO NORTH TO 5 ABOVE ZERO SOUTH.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 215 PM CST MON DEC 21 2015
LIFR/VLIFR FOG AND STATUS AT KBIS/KMOT WILL SLOWLY IMPROVE POSSIBLY
TO VFR BY LATE THIS AFTERNOON THROUGH EARLY EVENING.
HOWEVER...ANOTHER ROUND OF FOG AND STRATUS MAY BE POSSIBLE
TONIGHT. LIFR/VLIFR CONDITIONS AT KJMS CONTINUING THROUGH THE
NIGHT. VFR CONDITIONS EXPECTED AT KDIK/KISN THROUGH THE EVENING.
WIDESPREAD SNOW AND IFR CONDITIONS ARE EXPECTED ACROSS THE AREA
ON TUESDAY.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 6 AM TUESDAY TO MIDNIGHT CST
TUESDAY NIGHT FOR NDZ005-012-013-022-023-025.
&&
$$
SHORT TERM...AYD
LONG TERM...KS
AVIATION...AYD
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1252 AM CST MON DEC 21 2015
.UPDATE...
ISSUED AT 1253 AM CST MON DEC 21 2015
DENSE FOG ADVISORY CONTINUES FOR MUCH OF WEST AND CENTRAL NORTH
DAKOTA...AND EXPANDED THE ADVISORY TO INCLUDE MORE COUNTIES IN THE
SOUTHWEST AND IN THE NORTH CENTRAL. VISIBILITIES HAD IMPROVED AT
WILLISTON THE PAST COUPLE OF HOURS...BUT JUST EAST OF THERE
VISIBILITIES WERE 1/2-1/4 MILE. EXPANDED THE ADVISORY TO INCLUDE
DICKINSON AND HETTINGER (HETTINGER WAS ALREADY AT 1/4 MILE AND
SHORT TERM MODELS HAVE THIS EXPANDING NORTHWARD). ALSO EXPANDED
THE ADVISORY INTO BOTTINEAU...ROLETTE AND MCHENRY AND PIERCE
COUNTIES. OTHER CHANGE WAS RAISING MIN TEMPS FOR PARTS OF THE
SOUTH CENTRAL INTO THE JAMES VALLEY.
UPDATE ISSUED AT 834 PM CST SUN DEC 20 2015
HAVE ISSUED A DENSE FOG ADVISORY FOR MUCH OF NORTHWEST AND CENTRAL
NORTH DAKOTA. VISIBILITIES ON AREA WEATHER CAMERAS AND SURFACE
OBSERVATIONS BEGAN DROPPING QUICKLY AFTER 7 PM CENTRAL...MAINLY
ABOUT 30 TO 50 MILES EITHER SIDE OF THE MISSOURI RIVER VALLEY FROM
WILLISTON TO THE SOUTH DAKOTA LINE.
SURFACE HIGH PRESSURE OVER NORTHEAST NORTH DAKOTA IS KEEPING THE
DENSE FOG OUT OF THE EASTERN PORTIONS OF CENTRAL NORTH DAKOTA...AT
LEAST FOR THE TIME BEING. CLEAR TO PARTLY CLOUDY SKIES AND
CURRENTLY NO FOG IN THE SOUTHWEST WHERE SKIES WHICH SAW SOME SUN
TODAY. HOWEVER DEWPOINT DEPRESSIONS CONTINUE TO DROP HERE. THE
LATEST HRRR AND RAP MESOSCALE MODELS SHOW THE LOW STRATUS AND FOG
SPREADING EAST LATER TONIGHT AS THE SURFACE HIGH IN NORTHEAST ND
MOVES EAST. THESE MODELS ARE ALSO SHOWING LOW STRATUS RETURNING TO
THE SOUTHWEST AFTER MIDNIGHT. THUS IF THESE MODELS ARE CORRECT WE
MAY NEED TO ADD ON TO THE CURRENT ADVISORY LATE TONIGHT. FOR NOW
THOUGH IT DEPICTS WELL WHERE CURRENT VISIBILITIES ARE LOWEST.
TEXT PRODUCTS HAVE BEEN UPDATED
UPDATE ISSUED AT 633 PM CST SUN DEC 20 2015
WIDESPREAD STRATUS COVERS ALL OF CENTRAL NORTH DAKOTA ALONG AND
EAST OF THE HIGHWAY 83 CORRIDOR. WEST OF HERE...STRATUS ENDS OVER
BURKE AND MOUNTRAIL...SOUTH THROUGH MERCER...MORTON...GRANT AND
SIOUX COUNTIES. THEN A NARROW BREAK THE CLOUDS AND CLEAR
SKIES...WITH STRATUS AGAIN IN THE FAR WEST INTO NORTHEAST MONTANA.
FIRST THIS CLEAR STRIP IS WREAKING HAVOC WITH TEMPERATURES HAVE
FALLEN TO NEAR THE SINGLE DIGITS...WITH A 9 DEGREE F READING AT
TIOGA AT 6 PM CENTRAL. NOT FAR EITHER SIDE OF THIS CLEAR SPOT...
TEMPERATURES ARE IN THE LOWER TO MIDDLE 20S.
SECOND...ALTHOUGH VISIBILITIES HAVE IMPROVED OVER MOST OF
NORTHWEST NORTH DAKOTA...THERE REMAINS A SMALL AREA OF LOW
VISIBILITIES ON THE WESTERN EDGE OF THE STRATUS OVER CENTRAL NORTH
DAKOTA...ADJACENT TO THE NARROW CLEAR STRIP. THE HRRR AND HRRREXP
MESOSCALE MODELS EXPAND THE AREA OF LOW STRATUS ACROSS A GOOD
PORTION OF WESTERN AND CENTRAL NORTH DAKOTA TONIGHT...WHILE THE
NAMNEST AND RUC ARE NOT AS VIGOROUS EXPANDING THE LOWER
VISIBILITIES. DID ALLOW THE DENSE FOG ADVISORY TO EXPIRE BUT
DEPENDING ON HOW THINGS TREND THIS EVENING WE MAY NEED TO ISSUE
ANOTHER DENSE FOG ADVISORY LATER THIS EVENING.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 242 PM CST SUN DEC 20 2015
FOG AND PATCHY FREEZING DRIZZLE TONIGHT HIGHLIGHT THE SHORT TERM
FORECAST.
THE DENSE FOG ADVISORY ACROSS NORTHWEST NORTH DAKOTA REMAINS IN
EFFECT UNTIL 00 UTC. CERTAINLY POSSIBLE THAT THE ADVISORY MAY
NEED TO BE EXPANDED IN TIME AND OR AREA THROUGH THE EVENING AND
OVERNIGHT AS CURRENT STRATUS ACROSS WESTERN AND CENTRAL NORTH
DAKOTA IS EXPECTED TO BUILD DOWN POTENTIALLY INTO FOG. THIS
SCENARIO IS SUPPORTED BY THE 18 UTC NAM NEST AND 16-19 UTC HRRR
ITERATION VISIBILITY FORECASTS AND THE 12 UTC NAM/GFS BUFR
SOUNDINGS. GIVEN A DRY LAYER FORECAST TO BE ABOVE THE STRATUS DECK
TO SUBLIMATE ANY ICE CRYSTALS FROM MID TO UPPER LEVEL
CLOUDS...PATCHY FREEZING DRIZZLE IS ALSO POSSIBLE. DO NOT HAVE A
GREAT AMOUNT OF CERTAINTY REGARDING THE FREEZING DRIZZLE
POTENTIAL. THUS...CONFINED THE MENTION TO THE HIGHER TERRAIN OF
THE WEST WHERE CEILINGS ARE EXPECTED TO BE LOWEST.
FOR MONDAY...THE 12 UTC DETERMINISTIC AND ENSEMBLE SUITES ARE IN
GOOD AGREEMENT ON A RAPIDLY PROPAGATING SHORTWAVE ACROSS NORTH
DAKOTA TO SUPPORT A BAND OF LIGHT SNOW GENERALLY ACROSS THE CENTRAL
AND EAST. SNOWFALL ACCUMULATIONS OF LESS THAN ONE INCH ARE
EXPECTED.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 242 PM CST SUN DEC 20 2015
ACCUMULATING SNOWFALL POTENTIAL TUESDAY HIGHLIGHTS THE EXTENDED
FORECAST.
THE 12 AND INCOMING 18 UTC DETERMINISTIC AND ENSEMBLE SUITES ARE
IN AGREEMENT ON A SHORTWAVE EJECTING OUT OF WYOMING TUESDAY
MORNING...AND DEEPENING AS IT PROPAGATES EAST-NORTHEAST ACROSS
NORTH DAKOTA THROUGH THE DAY. LIGHT TO MODERATE SNOWFALL
ACCUMULATIONS MAY BE POSSIBLE...ESPECIALLY ACROSS NORTH CENTRAL
NORTH DAKOTA AND INTO THE JAMES RIVER VALLEY. HOWEVER...THE
HEAVIEST AMOUNTS AS OF NOW LOOK TO BE POSSIBLY FOCUSED OUTSIDE OF
THE CWA ACROSS NORTHEAST NORTH DAKOTA WHERE FRONTOGENETICAL
FORCING AND RESULTANT BANDING OF SNOW MAY BE GREATER. WILL
CONTINUE TO MONITOR THIS SYSTEM OVER THE COMING DAYS IN LIGHT OF
CHRISTMAS TRAVEL. THEREAFTER...THE UPPER LEVEL FLOW PATTERN OF
NEAR ZONAL ACROSS THE NORTHERN PLAINS IN THE BASE OF A VERY BROAD
AND LOW AMPLITUDE TROUGH MAY TRANSITION TO SPLIT FLOW BY LATE NEXT
WEEK AND WEEKEND. THIS WOULD SUPPORT SEASONABLE TEMPERATURES AND
RELATIVELY QUIET WEATHER.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1253 AM CST MON DEC 21 2015
WIDESPREAD IFR-LIFR CEILINGS EXPECTED FOR MUCH OF THE OVERNIGHT
HOURS THIS MORNING WITH A VERY LIGHT SURFACE FLOW. IFR VSBYS ALSO
EXPECTED AT KBIS/KMOT...AND THINK KISN AND KJMS SHOULD BECOME IFR IN
VSBY. MORE UNSURE ABOUT KDIK AT THIS TIME. IFR CONDITIONS SHOULD
IMPROVE FROM WEST TO EAST DURING THE DAYTIME ON MONDAY...BEGINNING
AROUND 15Z-16Z AT KISN/KDIK AND DURING THE AFTERNOON HOURS MONDAY
FOR CENTRAL ND TAF SITES.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 10 AM CST /9 AM MST/ THIS MORNING FOR
NDZ001>005-009>013-017>023-033>036-041-042-044>047-050.
&&
$$
UPDATE...JV
SHORT TERM...AYD
LONG TERM...AYD
AVIATION...JV
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
1140 PM EST SUN DEC 20 2015
.SYNOPSIS...
HIGH PRESSURE ALONG THE MID ATLANTIC COAST WILL MOVE EAST AND
ALLOW LOW PRESSURE TO MOVE THROUGH THE GREAT LAKES REGION MONDAY
INTO TUESDAY. THE LOW WILL DRAG A WEAK COLD FRONT THROUGH THE AREA
BEGINNING LATE MONDAY NIGHT. THE FRONT WILL COME BACK NORTH AS A
WARM FRONT TUESDAY NIGHT. UNSEASONABLY WARM WEATHER WILL CONTINUE
THROUGH MID WEEK WITH ONLY A SLIGHT COOL DOWN LATE IN THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
CIRRUS CONTINUES TO STREAM ACROSS THE REGION. THERE COULD BE SOME
THIN SPOTS MAINLY THROUGH THE FIRST HALF OF THE NIGHT BUT ON
BALANCE BELIEVE MOSTLY CLOUDY WILL BE GOOD. BIG QUESTION IS
WHETHER THE RAIN GETS INTO THE WESTERN COUNTIES BEFORE MORNING.
LATEST HRRR AND RAP CONTINUE THEIR DIFFERENCES WITH HRRR
CONTINUING TO BE FASTER WITH EAST SPREAD OF RAIN. THUS LOW
CONFIDENCE WITH TIMING OF PRECIP LATE TONIGHT. WILL USE AVERAGING
OF THESE MODELS WHICH STILL KEEPS POPS ABOUT WHERE THEY ARE
ALREADY.
MODERATE SOUTH WINDS AND INCREASING CLOUDS WILL MAKE IT HARD FOR
TEMPS TO FALL MUCH MORE.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY NIGHT/...
MONDAY BEGINS WITH RAIN MOVING INTO THE WEST HALF OF THE AREA.
MODELS CONTINUE TO SHOW LOW PRESSURE MOVING THROUGH THE GREAT
LAKES REGION WITH A STRENGTHENING LOW LEVEL JET AND GOOD MOISTURE
TRANSPORT INTO THE AREA. HAVE WENT WITH CATEGORICAL POPS FOR THE
ENTIRE AREA SPREADING WEST TO EAST THROUGH THE MORNING. MODELS
WRAP A DRY SLOT INTO THE WEST FOR THE AFTERNOON SO LOWERED POPS
FROM THE WEST THROUGH THE AFTERNOON. BY EVENING HOWEVER THE NAM
SHOWS A SHORT WAVE MOVING THROUGH THE BASE OF THE TROUGH IN THE
CENTRAL PLAINS. THROUGH THE OVERNIGHT THIS WAVE WILL MOVE ENE INTO
THE LOWER OHIO VALLEY. ACCORDINGLY MODELS BRING ANOTHER SLUG OF
MOISTURE INTO THE AREA FROM THE SOUTH...AFFECTING MAINLY
SOUTH/SOUTHEAST COUNTIES. SO WHILE POPS CONTINUE TO FALL ACROSS
THE NORTHWEST...HAVE HELP POPS IN THE HIGH CHANCE/LIKELY CATEGORY
FAR SOUTHEAST FOR THE SECOND HALF OF THE NIGHT. TUESDAY HIGH
PRESSURE AND DRIER AIR MOVE IN FROM THE WEST. HELD ONTO LOW
CHANCE POPS SOUTHEAST FOR THE MORNING BUT OTHERWISE SHOULD BE DRY.
TUESDAY NIGHT THE SOUTHERLY LOW LEVEL JET GETS GOING AGAIN AHEAD
OF ANOTHER LOW DEVELOPING IN THE SOUTHERN PLAINS. A WARM FRONT
EAST FROM THE LOW WILL TRACK NORTH ACROSS THE AREA OVERNIGHT
BRINGING MOIST MILD AIR BACK TO THE AREA. BROUGHT CHC POPS BACK TO
THE REGION AFTER MIDNIGHT WITH LIKELY POPS WEDNESDAY. WILL
CONTINUE LIKELY POPS WEDNESDAY NIGHT AS THE LOW...MOVING THROUGH
THE CENTRAL GREAT LAKES...DRAGS A COLD FRONT THROUGH THE AREA.
TEMPS MILD MONDAY AND TUESDAY TO SPRING-LIKE ON WEDNESDAY.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
QUITE A BIT OF VARIABILITY IN THE DETAILS FOR THE HOLIDAY AND THE
END OF THE WEEK. ACTIVE WEATHER PATTERN CONTINUES...BUT THE BEST
COLD AIR DOES NOT GET A CHANCE TO REACH INTO OUR AREA WITH THE
SOUTHEAST U.S. RIDGE HOLDING ON. THE COLD FRONT FOR THURSDAY IS
TRENDING FASTER AND THAT WILL IMPACT TEMPERATURES. HAVE LOWERED THEM
BY A FEW DEGREES...BUT IF THIS TREND CONTINUES WE MAY NEED FURTHER
REDUCTION. PRECIP CHANCES ACROSS THE EAST WILL BE EXITING. HIGH
PRESSURE ACROSS THE MID MISSISSIPPI VALLEY WILL BUILD ACROSS THE
UPPER OHIO VALLEY FOR THURSDAY NIGHT AND FRIDAY. BY SATURDAY THE
PATTERN WILL BE MORE AMPLIFIED AGAIN WITH A DEEP TROUGH ACROSS THE
FOUR CORNERS REGION. LATEST ECMWF HAS COME IN LINE CLOSER TO THE GFS
IN DRAGGING/SLOWING THE SOUTHERN ENERGY ACROSS THE CONTINENT...STILL
WELL DISCONNECTED FROM THE NORTHERN JET. HAVE PRECIP CHANCES
STARTING LATE FRIDAY NIGHT AND CONTINUING THROUGH THE DAY SUNDAY.
WARM FRONTAL ZONE DEVELOPS OVERHEAD AND MOVES LITTLE AS HIGH
PRESSURE AND STRONG ZONAL FLOW REMAINS ACROSS SOUTHERN CANADA JUST
NORTH OF THE LAKES. WAVES OF LOW PRESSURE LOOK TO RIDE THE FRONT
SLOWLY SINKING IT SOUTHWARD...POSSIBLY SUNDAY. WHILE THERE ARE SOME
DAY TO DAY FLUCTUATIONS IN TEMPERATURES...ALL OF THEM ARE STAYING
WELL ABOVE NORMAL.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
THINGS ARE GOING ABOUT AS EXPECTED. MAINLY MID LEVEL CIGS ARE OVER
THE AREA. SURFACE WINDS ARE MAINLY UNDER 20 KNOTS SO WILL KEEP THE
WIND SHEAR MENTIONED AS BEFORE. PLACES LIKE KERI AND KFDY WHICH
HAVE STRONGER SURFACE WINDS WILL NOT GET THE WIND SHEAR MENTION.
THE NEW MODELS ARE QUICKER BRINGING IN THE RAIN TODAY. HAVE SPED
THINGS UP ABOUT TWO HOURS. MVFR CIGS WILL BEGIN TO DEVELOP FROM
WEST TO EAST BEGINNING ABOUT MID MORNING. SOME IFR CIGS ARE
POSSIBLE TOWARD THE END OF THE TAF PERIOD. SOME GUSTS IN EXCESS OF
30 KNOTS ARE LIKELY ON MONDAY.
OUTLOOK...NON VFR POSSIBLE MONDAY AFTERNOON THROUGH TUESDAY
MORNING. NON VFR POSSIBLE AGAIN WEDNESDAY AND WEDNESDAY NIGHT.
&&
.MARINE...
HAVE RAISED THE SMALL CRAFT ADVISORY FOR TONIGHT AND THROUGH
MONDAY. TONIGHTS WINDS WILL BE MARGINAL...BUT WILL CERTAINLY
INCREASE DURING THE DAY MONDAY. LOW PRESSURE WILL BE TRACKING
NORTHEAST ACROSS THE CENTRAL LAKES TONIGHT...WEAKENING
CONSIDERABLY TUESDAY WHEN IT REACHES QUEBEC. THE SOUTH-SOUTHWEST
GRADIENT REMAINS STRONG...KEEPING WINDS FAIRLY STEADY STATE
TONIGHT BETWEEN 18 AND 25 KNOTS AND INCREASING TO UPWARDS OF 30
KNOTS MONDAY. WINDS NEVER SHIFT MUCH WITH THE DISSIPATING COLD
FRONT AND HIGH PRESSURE TAKING OVER BRIEFLY TUESDAY. THE NEXT
SYSTEM CENTERED AROUND THURSDAY MORNING WILL AGAIN HAVE STIFF
WINDS. HIGH PRESSURE BUILDS ACROSS THE OHIO VALLEY
FRIDAY...MAINTAINING THE PREDOMINATE SOUTHWEST FLOW.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 3 AM EST TUESDAY FOR LEZ147>149.
SMALL CRAFT ADVISORY UNTIL 9 PM EST MONDAY FOR LEZ142>146.
&&
$$
SYNOPSIS...TK
NEAR TERM...TK
SHORT TERM...TK
LONG TERM...OUDEMAN
AVIATION...KUBINA
MARINE...OUDEMAN
AREA FORECAST DISCUSSION...UPDATED
NWS NORMAN OK
1132 PM CST SUN DEC 20 2015
.AVIATION...21/06Z TAF ISSUANCE...
VFR CONDITIONS ARE EXPECTED TO PREVAIL THROUGH THE PERIOD. BREEZY
SOUTH WINDS ACROSS CENTRAL OKLAHOMA WILL RELAX THROUGH THE EARLY
MORNING HOURS...GRADUALLY VEERING TO THE WEST/NORTHWEST THROUGH
SUNRISE. ACROSS WESTERN OKLAHOMA...AND INTO NORTHERN TEXAS...
SOUTHWESTERLY WINDS WILL SLOWLY VEER TO THE WEST NORTHWEST THROUGH
THE MORNING HOURS. OVERALL... WINDS WILL CALM THROUGH THE MIDDLE
OF THE PERIOD AS SURFACE HIGH PRESSURE SPREADS ACROSS THE SOUTHERN
PLAINS.
JTK
&&
.PREV DISCUSSION... /ISSUED 636 PM CST SUN DEC 20 2015/
UPDATE...
ADJUSTED DRIZZLE/LIGHT RAIN CHANCES FOR TONIGHT.
DISCUSSION...
CURRENT WV IMAGERY REVEALS A DEVELOPING INTRUSION OF DRIER AIR OFF
THE PANHANDLES INTO NORTH/NWRN OKLAHOMA THIS EVENING. 21/00Z SFC
ANALYSIS PLACES THE SFC LOW NEAR SERN KS... WELL IN PHASE WITH THE
UPPER LOW VISIBLE ON WV. THE EXPERIMENTAL HRRR CONTINUES TO PULL
BACK PRECIP DEVELOPMENT FOR MOST OF CENTRAL OK THIS EVENING. FOR
THE PAST FEW HOURS... LIGHT SHOWERS/DRIZZLE CONTINUES TO DEVELOP
AHEAD OF THE SFC LOW OVER NERN OK/SWRN KS...ON THE FOCUS OF
DECENT ISENTROPIC ASCENT ACROSS THE ERN HALF OF OK. GIVEN THE
CURRENT PLACEMENT OF THE SFC LOW AND DEVELOPING CONDITIONS...
LIKE THE DELAYED DEVELOPMENT OF DRIZZLE/LIGHT RAIN FROM THE
EXPERIMENTAL HRRR...WHICH WILL CORRESPOND WITH INCREASING
MOISTURE AND FORCING FOR ASCENT LATER TONIGHT...WELL EAST OF I-35.
THEREFORE...TRIMMED BACK PRECIP CHANCES...KEPT LOW DRIZZLE AND
LIGHT RAIN CHANCES ALONG THE I-35 CORRIDOR...GRADUALLY TAPERING
THEMOFF TO THE EAST THROUGH THE EARLY MORNING HOURS.
JTK
PREV DISCUSSION... /ISSUED 237 PM CST SUN DEC 20 2015/
DISCUSSION...
SHORTWAVE TROUGH MOVING THROUGH THE CENTRAL AND SOUTHERN PLAINS
MAY STILL BRING A FEW SHOWERS TO PARTS OF EASTERN OKLAHOMA
TONIGHT. OTHERWISE... ALTHOUGH THE WINDS HAVE BEEN A BIT GUSTY...
HAVE NOT QUITE REACHED WIND ADVISORY ACROSS MUCH OF THE ADVISORY
AREA. WILL THEREFORE GO AHEAD AND CANCEL THE ADVISORY EARLY.
GUSTY SOUTH WINDS WILL RELAX SOME THIS EVENING BEFORE A WEAK COLD
FRONT WILL MOVE SOUTH THROUGH THE AREA WITH MUCH LIGHTER WINDS
FOR LATE TONIGHT AND MONDAY.
SHOULD SEE MORE SUN ON MONDAY... BUT TEMPS WILL BE CLOSE TO TODAY
AS SLIGHTLY COOLER AIRMASS WILL OVERSPREAD THE OKLAHOMA AND
NORTH TEXAS. SOUTH WINDS RETURN AND INCREASE FOR TUESDAY. THESE
WINDS WILL BRING MOISTURE QUICKLY BACK NORTHWARD... INTO AT LEAST
THE EASTERN HALF OF OKLAHOMA. A QUICK MOVING STORM SYSTEM WILL TRY
AND TAP INTO THIS MOISTURE PRODUCING SOME LATE DAY AND EVENING
THUNDERSTORMS ACROSS MAINLY SOUTHEAST/EASTERN OKLAHOMA. A FEW
STRONG TO PERHAPS SEVERE STORMS MAY OCCUR BEFORE THEY PUSH EAST OF
THE AREA.
ANOTHER WEAK COLD FRONT WILL THEN PUSH THROUGH WITH MAINLY
MILD/DRY WEATHER INTO THE DAY ON CHRISTMAS.
AS FOR BEYOND CHRISTMAS... STILL MUCH UNCERTAINTY REMAINS. MODELS
CONT TO FLIP FLOP BACK AND FORTH WHETHER TO CLOSE THE SYSTEM OFF
AND PRODUCE ABUNDANT PRECIP ACROSS THE SOUTHERN PLAINS OR KEEP IT
AN OPEN WAVE... WHICH PRODUCING VERY LITTLE PRECIP. NO MATTER
WHICH OCCURS... THE ONE FACTOR THAT SEEMS TO BE MORE CONSISTENT IS
THAT IT WILL BE TURNING COLDER WITH HIGHS SATURDAY AND SUNDAY
MAINLY IN THE 40S.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 41 57 34 64 / 10 0 0 0
HOBART OK 37 57 34 64 / 0 0 0 0
WICHITA FALLS TX 43 64 36 70 / 0 0 0 0
GAGE OK 31 55 31 64 / 0 0 0 0
PONCA CITY OK 36 52 31 62 / 20 0 0 0
DURANT OK 54 67 41 68 / 20 10 0 0
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
04/03/04
AREA FORECAST DISCUSSION
NWS Tulsa OK
1120 PM CST SUN DEC 20 2015
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG.
MVFR conditions prevail across eastern Oklahoma and Western
Arkansas this evening. Will some improvement in conditions at
the eastern Oklahoma TAF sites overnight with VFR conditions
expected across the whole area by Monday afternoon.
&&
.PREV DISCUSSION... /ISSUED 802 PM CST SUN DEC 20 2015/
DISCUSSION...
Cluster of showers within the warm conveyor ahead of the southern
high Plains vort max is moving quickly east this evening. A few
locations picked up .01 of an inch. The next round of precip will
be with the wave and front...which will sweep across the region
after midnight tonight. The best rain chances will be east of
Tulsa and north of I-40. Some isolated thunder will be possible
given weak elevated instability. Pops have been removed thru
midnight west of the first round of showers.
Lacy
PREV DISCUSSION... /ISSUED 600 PM CST SUN DEC 20 2015/
UPDATE...
Adjusted pops for the evening and overnight based on radar trends
and HRRR data. See discussion below.
DISCUSSION...
Shortwave trough clearly evident in satellite imagery this
evening...centered near Springfield CO moving quickly east. Lift
in advance of the system is interacting with the tongue of low
level moisture that has nosed north into OK. This has allowed
showers to begin popping up on radar over the past hour across NE
OK. The line of showers over Osage/Pawnee counties appears to be
the back edge of the precip potential. As elevated instability
increases downstream across NE OK into NW AR later tonight...the
potential for a few lightning strikes increases. Higher pops were
brought back westward in advance of the line of showers on
radar...and adjusted after midnight per latest HRRR data. The
greater coverage ahead of the wave/front will be from I-40
northward.
Lacy
PREV DISCUSSION... /ISSUED 536 PM CST SUN DEC 20 2015/
AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG.
MVFR conditions will be predominate through much of Tonight and
even into Monday morning in some locations in advance of a
cold front that will move through late Tonight into Monday morning.
Conditions will improve Monday afternoon.
PREV DISCUSSION... /ISSUED 339 PM CST SUN DEC 20 2015/
DISCUSSION...
Strong low level flow in advance of the wave currently over
northern New Mexico will continue to advect moisture
northward...and as lift increases overnight...scattered convection
is expected to develop. Northern portions of the forecast area
area nearer the steeper lapse rates thus warrant a mention of
isolate thunder later tonight. The associated cold front will pass
through the area Monday morning with high pressure building across
the area yielding a dry and warm Tuesday.
The next wave begins to influence the region late Tuesday as the
moist sector expands northward Tuesday night ahead of the sfc
low...which will track into north central OK before lifting
rapidly northeastward on Wednesday. Instability will recover
sufficiently to warrant a mention of thunderstorms during this
period...however higher instability is likely further south and
east of the forecast area.
Temperatures will remain unseasonably warm especially overnight
lows within this pattern...which will continue at least into next
weekend. Thereafter the forecast continues to remain highly
uncertain regarding both timing and placement of any potential
storm system for early next week.
TSA Watches/Warnings/Advisories...
OK...NONE.
AR...NONE.
$$
AVIATION...10
AREA FORECAST DISCUSSION
NWS PORTLAND OR
918 AM PST MON DEC 21 2015
.SYNOPSIS...ANOTHER VERY STRONG PACIFIC STORM SYSTEM IS EXPECTED TO
REACH THE S WA COAST THIS MORNING...AND MOVE E ACROSS SW WA TODAY
INTO EASTERN WA. THIS STORM IS EXPECTED TO PRODUCE STRONG WINDS
ACROSS MUCH 0F NORTHWEST OREGON AND FAR SOUTHERN PARTS OF SOUTHWEST
WA. SNOW IS EXPECTED IN THE CASCADES AND POSSIBLY DOWN AS LOW AS
HOOD RIVER AND PARKDALE. THE STORM MOVES EAST LATE TODAY AND TONIGHT.
ANOTHER FRONTAL SYSTEM SYSTEM WILL MOVE THROUGH TUESDAY AND
TUESDAY NIGHT. A COOLER UPPER TROUGH WILL DIG DOWN THE COAST FOR THE
LATTER PART OF THE WEEK... MAINTAINING THE UNSETTLED WEATHER PATTERN
AND DROPPING SNOW LEVELS CONSIDERABLY BY CHRISTMAS EVE DAY AND
CHRISTMAS DAY...THOUGH MOISTURE WILL BE DECREASING.
&&
.SHORT TERM...THE SURFACE LOW PRESSURE CENTER THIS MORNING IS
CURRENTLY JUST WEST OF BUOY 46089. THE BUOY AS OF AROUND 17Z MEASURED
A BAROMETRIC PRESSURE OF 981.4 MB. THIS IS A BIT STRONGER THAN THE
MODELS HAVE BEEN FORECASTING...INDICATING THE LOW PRESSURE CENTER
INTO THE UPPER 970S AS IT REACHES THE COAST. OTHERWISE...THIS SYSTEM
APPEARS TO BE TRACKING RIGHT ALONG WITH THE MODELS...CREATING HIGH
CONFIDENCE THAT IT WILL MOVE ONSHORE NEAR WILLAPA BAY LATER THIS
MORNING. WINDS HAVE STARTED INCREASING ALONG THE CENTRAL COAST AND
IN THE SOUTH AND CENTRAL WILLAMETTE VALLEY...WITH GUSTS ALREADY TO
40 TO 50 KT AS FAR NORTH AS TILLAMOOK...AND 30 TO 45 KT PEAK GUSTS
AT EUGENE...SALEM...AND AS FAR NORTH AS AURORA.
TEMPS IN THE GORGE AND CENTRAL HOOD RIVER VALLEY APPEAR TO BE STAYING
FOR THE MOST PART ABOVE FREEZING THIS MORNING...WHICH IS KEEPING SNOW
FROM ACCUMULATING BELOW 1500 FT.
NO CHANGES TO REST OF DISCUSSION. PREVIOUS DISCUSSION
FOLLOWS...SURFACE LOW WAS PASSING CLOSE TO BUOY 46005 BETWEEN 09Z AND
10Z THIS MORNING...ABOUT 300 NM W OF ABERDEEN WA. PRES ESTIMATED
AROUND 989 MB. THIS TRACKS FAIRLY WELL WITH MODELS IN
GENERAL AS FAR AS TRACK AND INTENSITY. NEWEST RUNS OF HRRR AND GFS
EARLY THIS MORNING SHOWED A TENDENCY FOR A SLIGHTLY STRONGER DEEPER
LOW THAN PREVIOUS RUNS...WITH GFS DOWN TO CLOSE TO 980 MB CENTER AS
IT MOVES ONSHORE NEAR WILLAPA BAY. OVERALL MODELS HAVE BEEN
PLEASANTLY CONSISTENT WITH THE TRACK OF THE LOW...COMING INLAND NEAR
THE LONG BEACH PENINSULA BETWEEN 18Z AND 20Z. MODELS CONTINUE TO
SHOW SURFACE LOW WEAKENING LITTLE AS IT MOVES INLAND ACROSS SW WA
TODAY. H8 WINDS TENDING TO PEAK ON THE ORDER OF 55 KT THIS MORNING
OVER NW OREGON...WHICH APPEARS TO BE A LITTLE STRONGER THAN THE
COMPARABLE SYSTEMS IN DEC 2012 AND JAN 1990. THE TRACK SUGGESTS THE
NORTHERN PART OF THE S WA COAST ZONE AND WILLAPA HILLS MAY BE SPARED
THE WINDS. THE FAST MOVEMENT OF THE LOW INFERS STRONG PRES RISES
MOVING IN BEHIND...SO MUCH OF THE REST OF THE AREA LOOKS ON TRACK
FOR THE EXPECTED WINDS. CASCADES MAY BE A LITTLE QUESTIONABLE FOR
HITTING THEIR HIGH WIND CRITERIA GIVEN FREE AIR H7 WINDS PEAKING
AROUND 65 TO 70 KT. OVERALL PREFER TO STICK WITH THE CURRENT WIND
WARNINGS AS THEY ARE NOW.
TEMPS IN THE GORGE AND HOOD RIVER VALLEY STARTING OUT A FEW DEGREES
ABOVE FREEZING EARLY THIS MORNING. NAM BUFR SOUNDINGS DO HOWEVER
SHOW SOME COOLING AS HEAVIER PRECIPITATION ARRIVES AFTER 14Z...
BEFORE WARMING KICKS IN AGAIN AFTER 18Z. WILL DOWNGRADE THE WINTER
STORM WARNING THERE TO AN ADVISORY DUE TO MARGINAL TEMPS AND
EXPECTED SHORT DURATION OF SNOW. PRECIPITATION SHIELD AHEAD OF THE
WARM FRONT THIS MORNING WILL BRING HIGH POPS THIS MORNING...BUT
DRIER WESTERLY FLOW IS FORCED IN QUICKLY TODAY...TRENDING THE
PRECIPITATION TOWARDS MORE OROGRAPHICALLY DRIVEN SHOWERS IN THE
AFTERNOON AND EVENING. WITH THE OROGRAPHIC LIFT CONTINUING INTO THE
EVENING...WILL CONTINUE WITH A LOW END WINTER STORM WARNING FOR THE
CASCADES TODAY THROUGH THIS EVENING. THE SNOW SHOWERS FOR THE
CASCADES WILL EASE UP OVERNIGHT AS ONSHORE FLOW WEAKENS. SNOW LEVELS
MAY DIP DOWN BELOW 2500 FEET IN THE HEAVIER PRECIPITATION THIS
MORNING AHEAD OF THE WARM FRONT...SO WILL KEEP THE ADVISORY FOR SNOW
GOING THROUGH THE MORNING.
TUE AND WED A COUPLE MORE SHORTWAVES EMBEDDED IN A VERY FAST
WESTERLY FLOW ALOFT MOVE ACROSS THE REGION. A 160 KT 300 MB JET OVER
NW OREGON TUE SINKS S TOWARDS THE CA BORDER WED. THIS SETS UP A
PATTERN FAVORABLE FOR SNOW IN THE CASCADES TUE AND WED...WITH SNOW
LEVELS LOWERING TO THE CASCADE FOOTHILLS AND HIGHER COAST RANGE.
-MCCOY/DE
.LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS...WEDNESDAY
NIGHT THROUGH SUNDAY...UPPER-LEVEL TROUGH DIGGING SOUTHWARD OVER THE
WESTERN CONUS WILL KEEP SHOWERS IN THE FORECAST WEDNESDAY NIGHT
THROUGH THURSDAY. SNOW LEVELS WILL BE DROPPING THURSDAY INTO THURSDAY
NIGHT TO 1000 TO 1500 FEET IN THE SOUTHERN HALF OF OUR AREA...BUT
SNOW LEVELS COULD DROP AS LOW AS 500 TO 1000 FT IN THE NORTHERN HALF
OF OUR AREA. SHOWERS WILL BE STARTING TO TAPER OFF LATE THURSDAY INTO
EARLY FRIDAY. WITH SNOW LEVELS GETTING SO LOW IN THE NORTHERN
WILLAMETTE VALLEY...WE COULD SEE A FEW SNOWFLAKES MIX IN WITH RAIN
SHOWERS ALL THE WAY DOWN TO THE VALLEY FLOOR LATE THURSDAY INTO EARLY
FRIDAY. WE LIKELY WILL NOT SEE ANY ACCUMULATION EXCEPT AT ELEVATIONS
ABOVE 500 FT. BY MIDDAY FRIDAY...RIDGING WILL BUILD HIGH PRESSURE
OVER THE AREA CUTTING OFF ANY CHANCE FOR PRECIPITATION THROUGH FRIDAY
NIGHT EXCEPT FOR A SLIGHT CHANCE OF FLURRIES IN THE CASCADES.
OUR NEXT SYSTEM BRINGS MORE PRECIPITATION ON SATURDAY INTO SUNDAY.
SNOW LEVELS COME BACK UP TO AROUND 3000-4000 FT WITH THIS
SYSTEM...BUT COLD AIR TRAPPED IN THE HOOD RIVER VALLEY AND CENTRAL
GORGE COULD MEAN A WINTRY MIX IN THESE LOWER AREAS. -MCCOY
&&
.AVIATION...A WARM FRONT MOVING THROUGH THE REGION IS BRINGING
RAIN AND PREDOMINANTLY MVFR CONDITIONS THIS MORNING. THERE ARE
POCKETS OF IFR CONDITIONS IN HEAVIER BANDS OF RAIN. SOUTH TO
SOUTHWEST WINDS TO INCREASE THROUGH THE MORNING BEHIND THE WARM
FRONT...WHICH SHOULD LIFT CIGS TO MAINLY VFR INTO TONIGHT ACROSS
THE AREA. WIND GUSTS OF SOUTH TO SOUTHWEST AT 50 TO 60 KT APPEAR
LIKELY FOR COASTAL TAF SITES THROUGH ABOUT 19Z MORNING...AND 40
TO 50 KT IN THE WILLAMETTE VALLEY THROUGH ABOUT 21Z. THE STRONGEST
WINDS SHOULD ONLY A COUPLE HOURS WITH LATEST MODEL GUIDANCE
SUGGEST THE STRONGEST WINDS INLAND MAY OCCUR AROUND KHIO...KMMV
AND KUAO. WINDS WILL SHIFT TO WESTERLY AS THE LOW PRES PUSHES
THROUGH THE REGION THIS AFTERNOON.
KPDX AND APPROACHES...BREEZY EAST WINDS AND MVFR CONDITIONS THIS
MORNING BEFORE STRONG SOUTHWEST WINDS DEVELOP AROUND MIDDAY AND
CONDITIONS TURN MAINLY VFR FOR THIS AFTERNOON AND EVENING. A 1 TO
3 HOUR PERIOD OF SOUTH TO SOUTHWEST WIND GUSTS OF 40 TO 50 KT
APPEAR LIKELY TO DEVELOP BETWEEN 19Z AND 22Z MONDAY. PYLE/NEUMAN
&&
.MARINE...A LOW PRES CENTER CURRENTLY LOCATED JUST NORTH OF BUOY
46089 WILL MOVE QUICKLY ONSHORE THIS MORNING ALONG THE LONG BEACH
PENINSULA. GALE FORCE SOUTHERLY WINDS OCCURRING OVER THE WATERS
THIS MORNING WITH A LEADING WARM FRONT. A STRONGER BURST OF
WESTERLY WINDS WILL OCCUR JUST TO THE SOUTH OF THE LOW AS IT
TRACKS EASTWARD ACROSS OUR NORTHERN WATERS THIS MORNING. AS A
RESULT...WIND GUSTS OF 45 TO 55 KT APPEAR LIKELY ACROSS OUR WATERS
THROUGH MIDDAY. THIS WILL LIKELY RESULT IN SEAS BUILDING ABRUPTLY
AND TOPPING OUT IN AT LEAST THE 20 TO 25 FT RANGE MIDDAY/EARLY
AFTERNOON. GIVEN THE FAST MOVING NATURE OF THIS STORM SYSTEM SEAS
SHOULD SETTLE BACK DOWN INTO THE MID TO UPPER TEENS FAIRLY QUICKLY
LATER THIS EVENING.
ANOTHER STORM SYSTEM APPEARS TO BRING GUSTY WEST-NORTHWEST WINDS
OF 35 TO 40 KT TUESDAY AND TUESDAY NIGHT. A WESTERLY SWELL LIKELY
IN EXCESS OF 20 FT WILL LIKELY PUSH INTO THE WATERS DURING THIS
TIME AND LINGER THROUGH MUCH OF WEDNESDAY. COASTAL FLOODING AND/OR
HIGH SURF ISSUES IN SOME SHAPE OR FORM APPEAR LIKELY ALONG OUR
COAST AS A RESULT.
UNSETTLED WEATHER WILL CONTINUE TO KEEP SEAS ABOVE 10 FT WITH
OCCASIONAL BOUTS OF 20 TO 35 KT WINDS THROUGH THURSDAY BEFORE HIGH
PRESSURE BUILDS TEMPORARILY INTO THE PACIFIC NORTHWEST AROUND
FRIDAY/SATURDAY. IT STILL APPEARS SEAS MAY DROP BELOW 10 FT FOR
12-36 PERIOD DURING THIS TIME BEFORE ANOTHER STORM SYSTEM MOVES
INTO THE REGION LATE IN THE WEEKEND. PYLE/NEUMAN
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...HIGH WIND WARNING UNTIL 7 PM PST THIS EVENING FOR CENTRAL
COLUMBIA RIVER GORGE-NORTHERN OREGON CASCADES-UPPER HOOD
RIVER VALLEY.
WINTER WEATHER ADVISORY UNTIL 1 PM PST THIS AFTERNOON FOR
CENTRAL COLUMBIA RIVER GORGE-UPPER HOOD RIVER VALLEY.
HIGH WIND WARNING UNTIL 4 PM PST THIS AFTERNOON FOR GREATER
PORTLAND METRO AREA-LOWER COLUMBIA-WESTERN COLUMBIA RIVER
GORGE.
HIGH WIND WARNING UNTIL 4 PM PST THIS AFTERNOON FOR CENTRAL
WILLAMETTE VALLEY-NORTHERN OREGON CASCADE FOOTHILLS-SOUTH
WILLAMETTE VALLEY.
WINTER WEATHER ADVISORY UNTIL NOON PST TODAY FOR NORTHERN OREGON
CASCADE FOOTHILLS.
WINTER STORM WARNING UNTIL 10 PM PST THIS EVENING FOR CASCADES
IN LANE COUNTY-NORTHERN OREGON CASCADES.
HIGH WIND WARNING UNTIL 4 PM PST THIS AFTERNOON FOR CENTRAL
COAST RANGE OF WESTERN OREGON-COAST RANGE OF NORTHWEST
OREGON.
HIGH WIND WARNING UNTIL 2 PM PST THIS AFTERNOON FOR CENTRAL
OREGON COAST-NORTH OREGON COAST.
WA...HIGH WIND WARNING UNTIL 7 PM PST THIS EVENING FOR CENTRAL
COLUMBIA RIVER GORGE-SOUTH WASHINGTON CASCADES.
WINTER WEATHER ADVISORY UNTIL 1 PM PST THIS AFTERNOON FOR
CENTRAL COLUMBIA RIVER GORGE.
HIGH WIND WARNING UNTIL 4 PM PST THIS AFTERNOON FOR GREATER
VANCOUVER AREA-I-5 CORRIDOR IN COWLITZ COUNTY-SOUTH
WASHINGTON CASCADE FOOTHILLS-WESTERN COLUMBIA RIVER GORGE.
HIGH WIND WARNING UNTIL 4 PM PST THIS AFTERNOON FOR SOUTH
WASHINGTON COAST-WILLAPA HILLS.
WINTER WEATHER ADVISORY UNTIL NOON PST TODAY FOR SOUTH
WASHINGTON CASCADE FOOTHILLS.
WINTER STORM WARNING UNTIL 10 PM PST THIS EVENING FOR SOUTH
WASHINGTON CASCADES.
PZ...STORM WARNING UNTIL 2 PM PST THIS AFTERNOON FOR COASTAL WATERS
FROM CAPE SHOALWATER WA TO FLORENCE OR OUT 60 NM.
SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL 4 AM PST
TUESDAY.
&&
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...HIGH WIND WARNING FROM 11 AM THIS MORNING TO 7 PM PST THIS
EVENING FOR CENTRAL COLUMBIA RIVER GORGE-NORTHERN OREGON
CASCADES-UPPER HOOD RIVER VALLEY.
WINTER WEATHER ADVISORY UNTIL 1 PM PST THIS AFTERNOON FOR
CENTRAL COLUMBIA RIVER GORGE-UPPER HOOD RIVER VALLEY.
HIGH WIND WARNING FROM 10 AM THIS MORNING TO 4 PM PST THIS
AFTERNOON FOR GREATER PORTLAND METRO AREA-LOWER COLUMBIA-
WESTERN COLUMBIA RIVER GORGE.
HIGH WIND WARNING FROM 9 AM THIS MORNING TO 4 PM PST THIS
AFTERNOON FOR CENTRAL WILLAMETTE VALLEY-NORTHERN OREGON
CASCADE FOOTHILLS-SOUTH WILLAMETTE VALLEY.
WINTER WEATHER ADVISORY UNTIL NOON PST TODAY FOR NORTHERN OREGON
CASCADE FOOTHILLS.
WINTER STORM WARNING UNTIL 10 PM PST THIS EVENING FOR NORTHERN
OREGON CASCADES.
WINTER STORM WARNING UNTIL 10 PM PST THIS EVENING FOR CASCADES
IN LANE COUNTY.
HIGH WIND WARNING FROM 8 AM THIS MORNING TO 4 PM PST THIS
AFTERNOON FOR CENTRAL COAST RANGE OF WESTERN OREGON-COAST
RANGE OF NORTHWEST OREGON.
HIGH WIND WARNING UNTIL 2 PM PST THIS AFTERNOON FOR CENTRAL
OREGON COAST.
HIGH WIND WARNING FROM 7 AM THIS MORNING TO 2 PM PST THIS
AFTERNOON FOR NORTH OREGON COAST.
WA...HIGH WIND WARNING FROM 11 AM THIS MORNING TO 7 PM PST THIS
EVENING FOR CENTRAL COLUMBIA RIVER GORGE-SOUTH WASHINGTON
CASCADES.
WINTER WEATHER ADVISORY UNTIL 1 PM PST THIS AFTERNOON FOR
CENTRAL COLUMBIA RIVER GORGE.
HIGH WIND WARNING FROM 10 AM THIS MORNING TO 4 PM PST THIS
AFTERNOON FOR GREATER VANCOUVER AREA-I-5 CORRIDOR IN
COWLITZ COUNTY-SOUTH WASHINGTON CASCADE FOOTHILLS-WESTERN
COLUMBIA RIVER GORGE.
HIGH WIND WARNING FROM 9 AM THIS MORNING TO 4 PM PST THIS
AFTERNOON FOR SOUTH WASHINGTON COAST-WILLAPA HILLS.
WINTER WEATHER ADVISORY UNTIL NOON PST TODAY FOR SOUTH
WASHINGTON CASCADE FOOTHILLS.
WINTER STORM WARNING UNTIL 10 PM PST THIS EVENING FOR SOUTH
WASHINGTON CASCADES.
PZ...STORM WARNING UNTIL 2 PM PST THIS AFTERNOON FOR COASTAL WATERS
FROM CAPE SHOALWATER WA TO FLORENCE OR OUT 60 NM.
SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL
4 AM PST TUESDAY.
&&
$$
INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/NWSPORTLAND
WWW.TWITTER.COM/NWSPORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON
FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS
COMMONLY REFERRED TO AS THE FORECAST AREA.
AREA FORECAST DISCUSSION
NWS PORTLAND OR
310 AM PST MON DEC 21 2015
.SYNOPSIS...ANOTHER VERY STRONG PACIFIC STORM SYSTEM IS EXPECTED TO
REACH THE S WA COAST THIS MORNING...AND MOVE E ACROSS SW WA TODAY
INTO EASTERN WA. THIS STORM IS EXPECTED TO PRODUCE STRONG WINDS
ACROSS MUCH 0F NORTHWEST OREGON AND FAR SOUTHERN PARTS OF SOUTHWEST
WA. SNOW IS EXPECTED IN THE CASCADES AND POSSIBLY DOWN AS LOW AS
HOOD RIVER AND PARKDALE. THE STORM MOVES EAST LATE MONDAY AND MONDAY
NIGHT. ANOTHER FRONTAL SYSTEM SYSTEM WILL MOVE THROUGH TUESDAY AND
TUESDAY NIGHT. A COOLER UPPER TROUGH WILL DIG DOWN THE COAST FOR THE
LATTER PART OF THE WEEK... MAINTAINING THE UNSETTLED WEATHER PATTERN
AND DROPPING SNOW LEVELS CONSIDERABLY BY CHRISTMAS EVE DAY AND
CHRISTMAS DAY...THOUGH MOISTURE WILL BE DECREASING.
&&
.SHORT TERM...SURFACE LOW WAS PASSING CLOSE TO BUOY 46005 BETWEEN
09Z AND 10Z THIS MORNING...ABOUT 300 NM W OF ABERDEEN WA. PRES
ESTIMATED AROUND 989 MB. THIS TRACKS FAIRLY WELL WITH MODELS IN
GENERAL AS FAR AS TRACK AND INTENSITY. NEWST RUNS OF HRRR AND GFS
EARLY THIS MORNING SHOWED A TENDENCY FOR A SLIGHTLY STRONGER DEEPER
LOW THAN PREVIOUS RUNS...WITH GFS DOWN TO CLOSE TO 980 MB CENTER AS
IT MOVES ONSHORE NEAR WILLAPA BAY. OVERALL MODELS HAVE BEEN
PLEASANTLY CONSISTENT WITH THE TRACK OF THE LOW...COMING INLAND NEAR
THE LONG BEACH PENINSULA BETWEEN 18Z AND 20Z. MODELS CONTINUE TO
SHOW SURFACE LOW WEAKENING LITTLE AS IT MOVES INLAND ACROSS SW WA
TODAY. H8 WINDS TENDING TO PEAK ON THE ORDER OF 55 KT THIS MORNING
OVER NW OREGON...WHICH APPEARS TO BE A LITTLE STRONGER THAN THE
COMPARABLE SYSTEMS IN DEC 2012 AND JAN 1990. THE STRACK SUGGESTS THE
NORTHERN PART OF THE S WA COAST ZONE AND WILLAPA HILLS MAY BE SPARED
THE WINDS. THE FAST MOVEMENT OF THE LOW INFERS STRONG PRES RISES
MOVING IN BEHIND...SO MUCH OF THE REST OF THE AREA LOOKS ON TRACK
FOR THE EXPECTED WINDS. CASCADES MAY BE A LITTLE QUESTIONABLE FOR
HITTING THEIR HIGH WIND CRITERIA GIVEN FREE AIR H7 WINDS PEAKING
AROUND 65 TO 70 KT. OVERALL PREFER TO STICK WITH THE CURRENT WIND
WARNINGS AS THEY ARE NOW.
TEMPS IN THE GORGE AND HOOD RIVER VALLEY STARTING OUT A FEW DEGREES
ABOVE FREEZING EARLY THIS MORNING. NAM BUFR SOUNDINGS DO HOWEVER
SHOW SOME COOLING AS HEAVIER PRECIPITATION ARRIVES AFTER 14Z...
BEFORE WARMING KICKS IN AGAIN AFTER 18Z. WILL DOWNGRADE THE WINTER
STORM WARNING THERE TO AN ADVISORY DUE TO MARGINAL TEMPS AND
EXPECTED SHORT DURATION OF SNOW. PRECIPITATION SHIELD AHEAD OF THE
WARM FRONT THIS MORNING WILL BRING HIGH POPS THIS MONRNING...BUT
DRIER WESTERLY FLOW IS FORCED IN QUICKLY TODAY...TRENDING THE
PRECIPITATION TOWARDS MORE OROGRAPHICALLY DRIVEN SHOWERS IN THE
AFTERNOON AND EVENING. WITH THE OROGRAPHIC LIFT CONTINUING INTO THE
EVENING...WILL CONTINUE WITH A LOW END WINTER STORM WARNING FOR THE
CASCADES TODAY THROUGH THIS EVENING. THE SNOW SHOWERS FOR THE
CASCADES WILL EASE UP OVERNIGHT AS ONSHORE FLOW WEAKEND. SNOW LEVELS
MAY DIP DOWN BELOW 2500 FEET IN THE HEAVIER PRECIPITATION THIS
MORNING AHEAD OF THE WARM FRONT...SO WILL KEEP THE ADVISORY FOR SNOW
GOING THROUGH THE MORNING.
TUE AND WED A COUPLE MORE SHORTWAVES EMBEDDED IN A VERY FAST
WESTERLY FLOW ALOFT MOVE ACROSS THE REGION. A 160 KT 300 MB JET OVER
NW OREGON TUE SINKS S TOWARDS THE CA BORDER WED. THIS SETS UP A
PATTERN FAVORABLE FOR SNOW IN THE CASCADES TUE AND WED...WITH SNOW
LEVELS LOWERING TO THE CASCADE FOOTHILLS AND HIGHER COAST RANGE.
.LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY...UPPER-LEVEL TROUGH
DIGGING SOUTHWARD OVER THE WESTERN CONUS WILL KEEP SHOWERS IN THE
FORECAST WEDNESDAY NIGHT THROUGH THURSDAY. SNOW LEVELS WILL BE
DROPPING THURSDAY INTO THURSDAY NIGHT TO 1000 TO 1500 FEET IN THE
SOUTHERN HALF OF OUR AREA...BUT SNOW LEVELS COULD DROP AS LOW AS 500
TO 1000 FT IN THE NORTHERN HALF OF OUR AREA. SHOWERS WILL BE STARTING
TO TAPER OFF LATE THURSDAY INTO EARLY FRIDAY. WITH SNOW LEVELS
GETTING SO LOW IN THE NORTHERN WILLAMETTE VALLEY...WE COULD SEE A FEW
SNOWFLAKES MIX IN WITH RAIN SHOWERS ALL THE WAY DOWN TO THE VALLEY
FLOOR LATE THURSDAY INTO EARLY FRIDAY. WE LIKELY WILL NOT SEE ANY
ACCUMULATION EXCEPT AT ELEVATIONS ABOVE 500 FT. BY MIDDAY
FRIDAY...RIDGING WILL BUILD HIGH PRESSURE OVER THE AREA CUTTING OFF
ANY CHANCE FOR PRECIPITATION THROUGH FRIDAY NIGHT EXCEPT FOR A SLIGHT
CHANCE OF FLURRIES IN THE CASCADES.
OUR NEXT SYSTEM BRINGS MORE PRECIPITATION ON SATURDAY INTO SUNDAY.
SNOW LEVELS COME BACK UP TO AROUND 3000-4000 FT WITH THIS
SYSTEM...BUT COLD AIR TRAPPED IN THE HOOD RIVER VALLEY AND CENTRAL
GORGE COULD MEAN A WINTRY MIX IN THESE LOWER AREAS. -MCCOY
&&
.AVIATION...A WARM FRONT WILL LIFT NORTHEASTWARD ACROSS THE AREA
THIS MORNING BRINGING WIDESPREAD MVFR CONDITIONS EARLY THIS
MORNING WITH PERHAPS A BRIEF PERIOD OR TWO OF IFR CONDITIONS AT A
FEW TAF SITES. STRONG SOUTH TO SOUTHWEST WINDS WILL THEN SPREAD
INTO THE REGION AS THE LOWER ATMOSPHERE DESTABILIZES. THIS SHOULD
PRODUCE MAINLY VFR CONDITIONS INTO TONIGHT ACROSS THE AREA...BUT
WIND GUSTS OF SOUTH TO SOUTHWEST WIND GUSTS OF 50 TO 60 KT APPEAR
LIKELY FOR COASTAL TAF SITES THIS MORNING...AND 40 TO 50 KT IN THE
WILLAMETTE VALLEY AROUND 20Z. THE STRONGEST WINDS SHOULD ONLY
LAST 1 TO 3 HOURS WITH LATEST MODEL GUIDANCE SUGGEST THE STRONGEST
WINDS MAY OCCUR AROUND KHIO...KMMV AND KUAO.
KPDX AND APPROACHES...INCREASING EAST WINDS AND MVFR CONDITIONS
WILL LIKELY ACCOMPANY A WARM FRONT THIS MORNING BEFORE STRONG
SOUTHWEST WINDS DEVELOP AND CONDITIONS TURN MAINLY VFR THIS
AFTERNOON AND EVENING. A 1 TO 3 HOUR PERIOD OF SOUTH TO SOUTHWEST
WIND GUSTS OF 40 TO 50 KT APPEAR LIKELY TO DEVELOP BETWEEN 19Z AND
22Z MONDAY. /NEUMAN
&&
.MARINE...A DEVELOPING LOW PRESSURE CURRENTLY JUST EAST-NORTHEAST
OF BUOY 46005...NEAR 130W...WILL MOVE EASTWARD INTO SOUTH
WASHINGTON COAST MIDDAY. STRONG SOUTH...AND THEN WEST WINDS WILL
DEVELOP SOUTH OF THE LOW PRESSURE AS IT TRACKS EASTWARD ACROSS OUR
NORTHERN WATERS THIS MORNING. AS A RESULT...WIND GUSTS OF 45 TO 55
KT APPEAR LIKELY ACROSS OUR WATERS THROUGH MIDDAY. THIS WILL
LIKELY RESULT IN SEAS BUILDING ABRUPTLY AND TOPPING OUT IN AT
LEAST THE 20 TO 25 FT RANGE MIDDAY/EARLY AFTERNOON. GIVEN THE FAST
MOVING NATURE OF THIS STORM SYSTEM SEAS SHOULD SETTLE BACK DOWN
INTO THE MID TO UPPER TEENS FAIRLY QUICKLY LATE THIS AFTERNOON OR
EARLY THIS EVENING.
ANOTHER STORM SYSTEM APPEARS TO BRING GUSTY WEST-NORTHWEST WINDS
OF 35 TO 40 KT TUESDAY AND TUESDAY NIGHT. A WESTERLY SWELL LIKELY
IN EXCESS OF 20 FT WILL LIKELY PUSH INTO THE WATERS DURING THIS
TIME AND LINGER THROUGH MUCH OF WEDNESDAY. COASTAL FLOODING AND/OR
HIGH SURF ISSUES IN SOME SHAPE OR FORM APPEAR LIKELY ALONG OUR
COAST AS A RESULT.
UNSETTLED WEATHER WILL CONTINUE TO KEEP SEAS ABOVE 10 FT WITH
OCCASIONAL BOUTS OF 20 TO 35 KT WINDS THROUGH THURSDAY BEFORE HIGH
PRESSURE BUILDS TEMPORARILY INTO THE PACIFIC NORTHWEST AROUND
FRIDAY/SATURDAY. IT STILL APPEARS SEAS MAY DROP BELOW 10 FT FOR
12-36 PERIOD DURING THIS TIME BEFORE ANOTHER STORM SYSTEM MOVES
INTO THE REGION LATE IN THE WEEKEND. /NEUMAN
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...HIGH WIND WARNING FROM 11 AM THIS MORNING TO 7 PM PST THIS
EVENING FOR CENTRAL COLUMBIA RIVER GORGE-NORTHERN OREGON
CASCADES-UPPER HOOD RIVER VALLEY.
WINTER WEATHER ADVISORY UNTIL 1 PM PST THIS AFTERNOON FOR
CENTRAL COLUMBIA RIVER GORGE-UPPER HOOD RIVER VALLEY.
HIGH WIND WARNING FROM 10 AM THIS MORNING TO 4 PM PST THIS
AFTERNOON FOR GREATER PORTLAND METRO AREA-LOWER COLUMBIA-
WESTERN COLUMBIA RIVER GORGE.
HIGH WIND WARNING FROM 9 AM THIS MORNING TO 4 PM PST THIS
AFTERNOON FOR CENTRAL WILLAMETTE VALLEY-NORTHERN OREGON
CASCADE FOOTHILLS-SOUTH WILLAMETTE VALLEY.
WINTER WEATHER ADVISORY UNTIL NOON PST TODAY FOR NORTHERN OREGON
CASCADE FOOTHILLS.
WINTER STORM WARNING UNTIL 10 PM PST THIS EVENING FOR NORTHERN
OREGON CASCADES.
WINTER STORM WARNING UNTIL 10 PM PST THIS EVENING FOR CASCADES
IN LANE COUNTY.
HIGH WIND WARNING FROM 8 AM THIS MORNING TO 4 PM PST THIS
AFTERNOON FOR CENTRAL COAST RANGE OF WESTERN OREGON-COAST
RANGE OF NORTHWEST OREGON.
HIGH WIND WARNING UNTIL 2 PM PST THIS AFTERNOON FOR CENTRAL
OREGON COAST.
HIGH WIND WARNING FROM 7 AM THIS MORNING TO 2 PM PST THIS
AFTERNOON FOR NORTH OREGON COAST.
WA...HIGH WIND WARNING FROM 11 AM THIS MORNING TO 7 PM PST THIS
EVENING FOR CENTRAL COLUMBIA RIVER GORGE-SOUTH WASHINGTON
CASCADES.
WINTER WEATHER ADVISORY UNTIL 1 PM PST THIS AFTERNOON FOR
CENTRAL COLUMBIA RIVER GORGE.
HIGH WIND WARNING FROM 10 AM THIS MORNING TO 4 PM PST THIS
AFTERNOON FOR GREATER VANCOUVER AREA-I-5 CORRIDOR IN
COWLITZ COUNTY-SOUTH WASHINGTON CASCADE FOOTHILLS-WESTERN
COLUMBIA RIVER GORGE.
HIGH WIND WARNING FROM 9 AM THIS MORNING TO 4 PM PST THIS
AFTERNOON FOR SOUTH WASHINGTON COAST-WILLAPA HILLS.
WINTER WEATHER ADVISORY UNTIL NOON PST TODAY FOR SOUTH
WASHINGTON CASCADE FOOTHILLS.
WINTER STORM WARNING UNTIL 10 PM PST THIS EVENING FOR SOUTH
WASHINGTON CASCADES.
PZ...STORM WARNING UNTIL 2 PM PST THIS AFTERNOON FOR COASTAL WATERS
FROM CAPE SHOALWATER WA TO FLORENCE OR OUT 60 NM.
SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL
4 AM PST TUESDAY.
&&
$$
INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/NWSPORTLAND
WWW.TWITTER.COM/NWSPORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON
FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS
COMMONLY REFERRED TO AS THE FORECAST AREA.
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
907 PM CST TUE DEC 22 2015
.UPDATE...
A WARM FRONT CURRENTLY STRETCHES FROM NEAR SEARCY ARKANSAS TO
TIPTONVILLE TENNESSEE. DENSE FOG HAS DEVELOPED JUST AHEAD OF THE
FRONT ACROSS PORTIONS OF NORTHEAST ARKANSAS AND THE MISSOURI
BOOTHEEL. THE FOG WILL DISSIPATE AS THE FRONT PUSHES
NORTHWARD...MAY NEED TO EXTEND THE TIMING FOR THE DENSE FOG
ADVISORY FOR RANDOLPH AND LAWRENCE COUNTIES A LITTLE PAST MIDNIGHT
BUT WILL HOLD OFF ON A DECISION FOR ANOTHER ONE TO TWO HOURS.
TEMPERATURES HAVE DROPPED LOWER THAN THE FORECASTED LOWS ACROSS
NORTHEAST ARKANSAS DUE TO THE SLOWNESS OF THE FRONT. HOWEVER THEY
ARE LIKELY AT OR NEAR THE LOW AT THIS TIME AND SHOULD RISE
OVERNIGHT AS THE FRONT PUSHES THROUGH.
MEANWHILE...STILL WAITING FOR GENERATION OF THUNDERSTORMS TO OCCUR
IN ARKLATEX WHICH SHOULD HAPPEN IN THE NEXT 2 TO 3 HOURS. THESE
THUNDERSTORMS WILL PUSH INTO EASTERN ARKANSAS BETWEEN 4-6 AM CST. HOWEVER
A MORE IMMEDIATE CONCERN MAY BE THE LARGE AREA OF RAIN THAT IS
OCCURRING ACROSS SOUTHERN MISSISSIPPI TONIGHT. THE RAIN SEEMS TO
BE ASSOCIATED WITH A SECONDARY BOUNDARY. THE 18Z GFS SHOWS THIS
AREA WITH SOME ADDITIONAL DEVELOPMENT OVER NE LOUISIANA CREEPING
INTO NORTH MISSISSIPPI OVERNIGHT WHILE THE NAM KEEPS THE RAIN TO
THE SOUTH AND EAST OF THE CWA. THE HRRR HAS BEEN IN AGREEMENT WITH
THE NAM UP UNTIL THE LAST RUN AT 1Z WHICH SEEMS TO BE SOMEWHAT IN
BETWEEN. FOR NOW LIKELY POPS ACROSS THE WESTERN HALF OF THE CWA
AND ACROSS PORTIONS OF NORTHEAST MISSISSIPPI SEEMS REASONABLE.
KRM
&&
.DISCUSSION... /ISSUED 308 PM CST TUE DEC 22 2015/
.THE POTENTIAL FOR A SIGNIFICANT SEVERE THUNDERSTORM OUTBREAK
ACROSS THE ENTIRE MIDSOUTH CONTINUES TO INCREASE STRONG TORNADOES
ARE POSSIBLE...
AN ABNORMAL WEATHER PATTERN IS IN PLACE ACROSS THE
MIDSOUTH...FEATURING VERY UNSTABLE CONDITIONS AND WHAT LOOKS TO BE
AN ADEQUATE AMOUNT OF SHEAR TO BALANCE THE THERMODYNAMICS.
TEMPERATURES ARE IN THE MIDDLE 60S TO LOW 70S ACROSS THE
REGION...AROUND 25 DEGREES ABOVE NORMAL. DEW POINTS ARE IN THE
UPPER 50S TO LOW 60S...BUT SOUTHERLY WIND WILL KEEP DEWPOINTS
RISING AS GULF MOISTURE FLOODS THE MIDSOUTH. OVER THE NEXT 24
HOURS OR SO A VERY BROAD TROUGH WILL SHIFT ACROSS THE PLAINS. LATE
TONIGHT INTO EARLY TOMORROW ITS AXIS SHOULD BE OVER CENTRAL
OKLAHOMA...WITH A NEGATIVELY TILTED SHORTWAVE APPROACHING THE
MISSISSIPPI RIVER VALLEY. ONE OF THE MORE SIGNIFICANT CHANGES IN
MODEL GUIDANCE OVER THE LAST 24 HOURS IS THE DEVELOPMENT OF
DIURNAL THUNDERSTORMS ALONG AND WEST OF THE MISSISSIPPI RIVER
TONIGHT. BOTH THE NAM AND GFS INDICATE IN EXCESS OF 1000 J/KG CAPE
IN PLACE AS THE SHORTWAVE APPROACHES. A STRONG LLJ NEAR 100KT IS
ALREADY IN PLACE...STREAMING FROM THE SOUTHWEST GULF OF MEXICO
ACROSS THE MIDSOUTH. IF THUNDERSTORMS DEVELOP...THEY WOULD ALMOST
CERTAINLY QUICKLY STRENGTHEN TO SEVERE LIMITS. SIGNIFICANT HEIGHT
FALLS...ON THE ORDER OF 4DM/12HR WILL BEGIN AROUND MIDNIGHT...WITH
AS MUCH AS 8DM/12HR MY MIDDAY TOMORROW. THE STORM PREDICTION
CENTER HAS INCLUDED MOST OF THE MIDSOUTH WEST OF THE MISSISSIPPI
RIVER IN AN ENHANCED OUTLOOK FOR SEVERE THUNDERSTORMS TONIGHT.
STILL FEEL LIKE THE MOST WIDESPREAD AND STRONGEST STORMS WILL BE
TOMORROW...WITH THE HIGHEST THREAT ALONG THE SOUTH OF THE INTERSTATE
40 CORRIDOR...BUT SEVERE WEATHER IS POSSIBLE ACROSS ALL OF THE
MIDSOUTH. THE STRONG LLJ WILL BRING A COASTAL AIRMASS ACROSS THE
MIDSOUTH TOMORROW AFTERNOON. DEW POINTS WILL CERTAINLY BE IN THE
MIDDLE 60S ACROSS MOST OF THE AREA...AND MAY CLIMB INTO THE UPPER
60S IN NORTH MISSISSIPPI. RESULTING SURFACE BASED INSTABILITY
COULD EXCEED 1200J/KG. LOW LEVEL LAPSE RATES ON THE ORDER OF 6C
AND 30-40 DEGREES OF DIFFLUENCE ALOFT SHOULD HELP MAINTAIN
SUSTAINED HEALTHY UPDRAFTS. 0-3KT SRH WILL BE IN EXCESS OF
300M^2/S^2 IN NORTH MISSISSIPPI TOMORROW AT MIDDAY...WEAKENING
ONLY SLIGHTLY TO AROUND 250M^2/S^2 BY SUNSET. AS A RESULT A FEW
STRONG TORNADOES ARE POSSIBLE...ESPECIALLY IN NORTH MISSISSIPPI.
IN ADDITION...DAMAGING WIND AND LARGE HAIL ARE THREATS AREA WIDE
TOMORROW. THE SEVERE THREAT SHOULD DIMINISH AFTER SUNSET.
THURSDAY SHOULD BE MOSTLY DRY...ALTHOUGH A FEW SHOWERS MAY LINGER
IN FAR EASTERN PORTIONS OF THE MIDSOUTH NEAR THE ALABAMA STATE
LINE AND TENNESSEE RIVER.
WE WILL REMAIN IN AN ACTIVE PATTERN
AFTER TOMORROW. FRIDAY THROUGH MONDAY...LONG RANGE MODELS INDICATE
THE FRONT WILL BEGIN TO RETURN BACK NORTH AS A WARM FRONT ACROSS
THE FORECAST AREA ON CHRISTMAS DAY. THIS WILL RESULT IN THE
DEVELOPMENT OF ADDITIONAL SHOWERS AND THUNDERSTORMS ACROSS THE MID
SOUTH THURSDAY NIGHT AND ESPECIALLY ON FRIDAY. ADDITIONAL STRONG
TO SEVERE THUNDERSTORMS MAY BE POSSIBLE ON CHRISTMAS DAY. LONG
TERM MODELS BEGIN TO DIVERGE GREATLY WITH RUN TO RUN CONTINUITY AS
AN UPPER LEVEL LOW MOVES FROM THE PLAINS INTO THE MISSISSIPPI
VALLEY TOWARDS EARLY NEXT WEEK. THUS OVERALL CONFIDENCE IN
PRECIPITATION CHANCES MAY NEED TO BE ADJUSTED IN SUBSEQUENT
FORECASTS FOR THIS WEEKEND AND ESPECIALLY EARLY NEXT WEEK.
30
&&
.AVIATION...
00Z TAFS
DENSE FOG HAS DEVELOPED ACROSS THE BOOTHEEL AND KHKA ON THE
LEADING EDGE OF THE FRONTAL BOUNDARY STARTING TO MOVE BACK NORTH.
AS THIS FRONT CONTINUES MOVING NORTH THAT DENSE FOG COULD MOVE
INTO KJBR. NOT CONFIDENT TO ADD TO TAFS BUT SOMETHING TO WATCH.
LOW CLOUDS OVER NORTH MISSISSIPPI WILL PUSH NORTH ACROSS THE MID-
SOUTH THIS EVENING. EXPECT GENERALLY MVFR CONDS WITH IFR AT KTUP.
LATER TONIGHT A STRONG STORM SYSTEM WILL TRACK INTO THE REGION
AND SHRAS/TSRAS WILL DEVELOP AND MOVE INTO THE MIDSOUTH LATE
TONIGHT INTO WED AM. A COUPLE OF ROUNDS OF SHRAS/TSRAS ARE
POSSIBLE ACROSS THE AREA THROUGH THE END OF THE PERIOD. MVFR CIGS
DURING THE MORNING WILL IMPROVE TO MVFR/VFR IN THE AFTERNOON AS
MIXING INCREASES.
LIGHT WINDS INITIALLY WILL QUICKLY INCREASE...ABOVE 8 KTS AT KMEM
BY 04-05Z...AND BECOME GUSTY OVERNIGHT. STRONG GUSTY SOUTH WINDS
EXPECTED WED ESPECIALLY AT KJBR/KMEM WHERE GUSTS COULD HIT 30 KTS.
SJM
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...DENSE FOG ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR CLAY-CRAIGHEAD-
GREENE-LAWRENCE-MISSISSIPPI-RANDOLPH.
MO...DENSE FOG ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR DUNKLIN-
PEMISCOT.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MORRISTOWN TN
1000 PM EST TUE DEC 22 2015
.DISCUSSION...
CURRENT WATER VAPOR IMAGERY AND RAP UPPER AIR ANALYSIS INDICATES A
LONGWAVE TROUGH BEGINNING TO TAKE ON A NEGATIVE TILT ACROSS THE
CENTRAL AND SOUTHERN PLAINS. CLOSER TO HOME A SHORTWAVE TROUGH CAN
BE NOTED ACROSS THE NORTHERN GULF COAST. HI-RES MODELS INDICATE
THAT WIDESPREAD SHOWERS ALONG THIS GULF WAVE WILL MOVE INTO THE
AREA LATE TONIGHT INTO EARLY TOMORROW MORNING. MODELS HAVE
BEEN CONSISTENT THAT THE HEAVIEST PRECIPITATION WILL FALL ACROSS
EASTERN PORTIONS OF THE AREA AND THIS IS WHERE THE HIGHEST POPS
ARE. LOOKING AT THE LATEST OBSERVATIONS...IT APPEARS THE
PRECIPITATION IS BEHIND SCHEDULED AND SHIFTED POPS BACK WITH THE
HIGHEST CHANCES FOR RAIN NEAR SUNRISE. LOW LEVEL MOISTURE IS
PLENTIFUL WITH SURFACE DEWPOINTS ALREADY IN THE MID TO UPPER 50S.
THIS COMBINATION HAS LED TO SOME PATCHY DENSE FOG ACROSS THE AREA.
FOR NOW...HAVE NOT ISSUED AN ADVISORY BUT IT MAY BECOME NECESSARY
IF TRENDS CONTINUE.
&&
.PRELIMINARY POINT TEMPS/POPS...
CHATTANOOGA AIRPORT, TN 57 71 63 74 / 100 70 80 60
KNOXVILLE MCGHEE TYSON AIRPORT, TN 54 69 61 73 / 100 80 70 60
OAK RIDGE, TN 57 69 62 72 / 90 80 80 60
TRI CITIES AIRPORT, TN 54 67 57 70 / 100 90 50 70
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
MA
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1233 PM EST MON DEC 21 2015
.SYNOPSIS...
A DEEP SOUTHERLY FLOW AHEAD OF A COLD FRONT ACROSS THE MISSISSIPPI
VALLEY IS GOING SPREAD MOISTURE OUR WAY THIS AFTERNOON AND
TONIGHT. THE FRONT WEAKENS AND LIFTS NORTH ACROSS THE GREAT LAKES
BY TUESDAY. HOWEVER...ANOTHER FRONT MOVES IN BY MIDWEEK WITH
CONTINUED SOUTHERLY FLOW AND MUCH ABOVE NORMAL TEMPERATURES TO
PROVIDE PERIODS OF MODERATE TO HEAVY RAINFALL.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1145 AM EST MONDAY...
BAND OF LIGHT SHOWERS CONTINUES TO ADVANCE EASTWARD TO THE BLUE
RIDGE. EVEN THOUGH RAIN HAS MOVED ACROSS THE MOUNTAINS...DEW
POINTS ARE NOT RECOVERING VERY QUICKLY. FOR THIS UPDATE..INCREASED
POPS ALONG THE BLUE RIDGE AND FOOTHILL COUNTIES INTO EARLY THIS
AFTERNOON. AGAIN USED THE HRRR FOR THIS UPDATE. ALSO ADJUSTED DEW
POINTS WITH A GRADUAL RISE INTO THIS EVENING.
AS OF 933 AM EST MONDAY...
INCREASED POPS AS LIGHT RAIN CONTINUES TO ADVANCE EASTWARD THIS
MORNING. THE HRRR IS THE ONLY MODEL SEEN SHOWING THIS RAIN ENTER
THE WEST THIS MORNING. HRRR HAS THIS RAIN MOVING EAST OF THE BLUE
RIDGE THIS AFTERNOON...BUT WILL KEEP POPS LOW WITH LOW AND MID
LEVELS BEING DRY VIA MORNING SOUNDING. IF PRECIPITATION DOES PUSH
EAST IT WILL REMAIN LIGHT...POSSIBLY JUST SPRINKLES.
AS OF 223 AM EST MONDAY...
OVERALL SHIFT FROM COLD TO WARM STARTS TODAY. MOISTURE WILL CONTINUE
TO INCREASE AS PWATS OF 1 TO 1.25 INCHES OVER THE TN VALLEY AND GULF
STATES WORK EAST TOWARD THE FORECAST AREA BY THIS EVENING. MODELS
ARE IN GENERAL AGREEMENT ON THE PATTERN BUT SOME DIFFERENCES IN HOW
FAST RAINFALL MOVES IN AND PLACEMENT OF HEAVIER AMOUNTS OVERNIGHT.
BOTH THE NAM/ECM INDICATE A NARROW TONGUE OF MOISTURE ACROSS THE
BLUE RIDGE BY THE END OF THE DAY WITH LIGHT QPF...WHILE THE GFS IS
DRY. WITH MODELS INDICATE SOME UPPER DIVERGENCE AND LOW LVL
CONVERGENCE...DECIDED TO KEEP AT LEAST SLIGHT CHANCE ACROSS THE BLUE
RIDGE THIS AFTERNOON...WITH MOISTURE AND LIFT MORE PREVALENT BY
7PM OVER THE MTNS OF WV/FAR SW VA.
WITH SFC HIGH WELL OFF THE COAST AND MAINLY CLOUDY SKIES HIGHS TODAY
THOUGH MILD WILL BE HELD IN CHECK...RANGING FROM THE UPPER 40S TO
MID 50S.
TONIGHT...SFC FRONT MAKES ITS WAY EAST INTO THE OHIO/TN VALLEY WITH
STRONG FORCING IN THE UPPER LEVELS MOVING ACROSS OUR AREA AFTER
MIDNIGHT. MODELS AGREE IN TWO AREAS OF HIGHER RAINFALL...MAINLY
ALONG THE FRONT FROM MID TN INTO THE OHIO VALLEY AND A SECONDARY
AXIS ACROSS GA/SC INTO THE PIEDMONT OF NC...WITH LIGHTER QPF IN OUR
AREA. THE 0Z NAM IS THE DRIEST FOLLOWED BY THE ECMWF...WITH THE GFS
HAVING MORE QPF. THINK WITH THE FORCING AND SW FLOW AND HIGHER
PWATS...MOST AREAS WILL SEE MEASURABLE RAINFALL SO HAVE AT LEAST
LIKELY IN THE MAJORITY OF THE FORECAST AREA BY DAWN TUESDAY...WITH
CATEGORICAL POPS IN THE MTNS OF WV/FAR SW VA. RAINFALL AMOUNTS
TONIGHT WILL BE A QUARTER INCH OR LESS...THOUGH SOME ISOLATED
POCKETS OF HALF INCH AMOUNTS ARE POSSIBLE. WITH CLOUDS AND
RAIN...PLUS 8H TEMPS OF +10 TO +12C...LOWS WILL BE IN THE 40S...AS
RAIN ALLOWS TEMPS TO FALL TO THE DEWPOINTS IN THE 40S. THOUGH WITH
SW FLOW INCREASING OVER THE HIGHER SLOPES OF WV/FAR SW VA INTO
NC...TEMPS HERE MAY STAY ABOVE 50 THROUGH THE NIGHT.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY NIGHT/...
AS OF 300 AM EST MONDAY...
A DEEP SOUTHWEST FLOW WILL PUMP MOISTURE INTO OUR REGION TUESDAY
INTO WEDNESDAY. UPPER DISTURBANCES ROTATING ALONG THE UPPER FLOW
WILL CONTINUE THE OVERRUNNING SHOWERS. THE GFS AND ECM INDICATED
MAIN SHORTWAVE WILL GENERATE CONVECTION WHICH MOVES EAST ACROSS THE
SOUTHEAST US EARLY TUESDAY...THEN MOVES OFF COAST TUESDAY AFTERNOON
AND EVENING. THIS RESULTS IN DRYING TREND FOR OUR AREA...WITH
MAJORITY OF MOISTURE PUSHED OFF THE COAST. THE NAM SOLUTION IS LESS
AGGRESSIVE WITH THE DRYING IDEA. HIGH TEMPERATURES ON TUESDAY WILL
RANGE FROM THE MID 50S IN THE MOUNTAINS TO THE LOWER 60S IN THE
PIEDMONT.
TUESDAY NIGHT INTO WEDNESDAY...AN UPPER LEVEL TROUGH SWINGS OUT
OF THE ROCKIES AND INTO THE PLAINS. THIS SYSTEM WILL PUSH MORE
WAVES AND GULF MOISTURE INTO THE REGION STARTING LATE TUESDAY NIGHT.
THE NORTH CAROLINA COUNTIES WILL HAVE THE BEST CHANCE OF RAIN
TUESDAY NIGHT. RAIN WILL SPREAD NORTHWARD ALONG THE BLUE RIDGE
HEADING INTO WEDNESDAY MORNING. LOW TEMPERATURES TUESDAY NIGHT WILL
VARY FROM THE MID 40S IN THE NORTHWEST MOUNTAINS TO THE MID 50S IN
THE SOUTHEAST. THE SURFACE WAVE ASSOCIATED WITH THE UPPER TROUGH IS
EXPECTED TO TRACK FROM THE SOUTHERN PLAINS INTO THE GREAT LAKES
REGION BY WEDNESDAY AFTERNOON. PERIODS OF RAIN...HEAVY AT TIMES
EXPECTED WEDNESDAY INTO WEDNESDAY NIGHT. FLOODING PROBLEMS MAY
DEVELOP WHERE THE AXIS OF HEAVY RAIN SETS UP. SEE HYDRO SECTION
FOR MORE DETAILS. RAISED QPF FOR WEDNESDAY WITH AMOUNTS VARYING
FROM 0.65 IN THE NORTHWEST TO AS MUCH AS 3 INCHES ALONG THE
SOUTHERN BLUE RIDGE. HIGH TEMPERATURES ON WEDNESDAY WILL BE AROUND
20 DEGREES ABOVE NORMAL WITH READINGS FROM THE UPPER 50S IN THE
NORTHWEST MOUNTAINS TO AROUND 70 DEGREES IN THE PIEDMONT.
LOW TEMPERATURES WEDNESDAY NIGHT WILL GENERALLY BE IN THE MID 50S IN
THE WEST TO THE LOWER 60S IN THE EAST. THE MILD UNSETTLED WEATHER
CONTINUE THURSDAY INTO THURSDAY NIGHT. THE BEST CHANCE OF RAIN ON
THURSDAY WILL OCCUR IN THE WEST AS SUPPORT BY BOTH GFS AND ECM.
CHRISTMAS EVE WILL BE UNSEASONABLY WARM WITH HIGHS FROM MID 60S IN
THE WEST TO THE MID 70S IN THE EAST. ON THURSDAY NIGHT...SHORTWAVE
SLICES EAST WITH HIGH PRESSURE BUILDING SOUTH OUT OF THE OHIO
VALLEY INTO OUR REGION. LOW TEMPERATURES THURSDAY NIGHT INTO FRIDAY
MORNING WILL DROP INTO THE LOWER 40S IN THE NORTHWEST TO THE MID 50S
IN THE SOUTHEAST.
&&
.LONG TERM /FRIDAY THROUGH SUNDAY/...
AS OF 330 PM EST SUNDAY...
THE LONG RANGE FORECAST FOR THE AREA DIFFERS FROM MODEL TO MODEL.
THE GFS PUSHES THE AXIS OF PRECIPITATION TO THE SOUTHEAST COAST
WITH HIGH PRESSURE BUILDING OVER THE AREA FROM THE NORTH. THE ECM
STALLS A FRONT AND PRECIPITATION OVER THE AREA INTO
FRIDAY...LIFTING IT NORTH WITH THE NEXT SYSTEM COMING OUT OF THE
ROCKIES. THE DIFFERENCES IN THE MODELS LOOKS TO CENTER AROUND AN
UPPER LEVEL RIDGE IN THE WESTERN ATLANTIC. THE GFS IS FARTHER TO
THE EAST WHICH ALLOWS THE RAIN TO MOVE TO THE COAST. AS WITH
NEIGHBORING OFFICES...WILL KEEP LOW POPS IN THE FORECAST FOR
UNCERTAINTY. MODELS CONTINUE TO RETROGRADE THE WESTERN ATLANTIC
RIDGE WESTWARD INTO THE THE GULF. THIS WILL KEEP THE EAST COAST IN
WARM SOUTHERLY FLOW AND A STORM TRACK ACROSS THE OHIO VALLEY. RAIN
CHANCES FOR THIS CHRISTMAS WEEKEND WILL BE HIGHEST IN SOUTHEASTERN
WEST VIRGINIA AND LESS LIKELY ACROSS THE PIEDMONT AND SOUTHSIDE
VIRGINIA.
THE AREA WILL REMAIN ON THE WARM SIDE OF ANY FRONT WITH
TEMPERATURES CONTINUING TO RUN 20F-25F WARMER THAN NORMAL.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
AS OF 1230 PM EST MONDAY...
A BAND OF LIGHT SHOWERS MOVED ACROSS THE MOUNTAINS TO THE BLUE
RIDGE THIS MORNING. RELATIVELY DRY LOW LEVELS REMAINS EAST OF THE
BLUE RIDGE TO LIMIT RAINFALL TO A COUPLE OF CLICKS IN THE TIPPING
BUCKET. CELLINGS WILL LIKELY REMAIN VFR AT ROA/BCB INTO THIS
AFTERNOON. THIS RAIN BAND DOES NOT APPEAR IT WILL MAKE IT TO
LYH...BUT MAY HELP LIFT CURRENT LOW DECK TO VFR BY MID AFTERNOON.
NO MODELS HAVE THIS RAIN COMING NEAR DANVILLE. BLF/LWB HAD LIGHT
RAIN LATE THIS MORNING AND WILL SEE VFR CONDITIONS THROUGH THE
REST OF THE AFTERNOON.
FOR TONIGHT LOOK FOR CIGS TO DROP TO MVFR WITH LIGHT TO MODERATE
RAIN MOVING IN. SOME CIGS WITH A SE WIND INTO THE PIEDMONT AND
BLUE RIDGE ARE EXPECTED TO DROP TO BELOW 1KFT.
.EXTENDED AVIATION DISCUSSION...
GENERALLY POOR AVIATION CONDITIONS EXPECTED THROUGH THE WEEK WITH
MULTIPLE UPPER DISTURBANCES ROTATING NORTHEAST THROUGH THE REGION
FROM A MEAN MID-U.S. DEEP UPPER TROUGH. AT THIS TIME...THE MOST
FAVORABLE PERIODS FOR SUBSTANTIAL RAINFALL AND IFR CIGS/VSBYS WILL
BE MON NIGHT...AND AGAIN TUE NIGHT THROUGH EARLY WED. EVEN WHEN
NOT RAINING...LOW CLOUDS AND DRIZZLE LIKELY WITH VERY MOIST
ATMOSPHERE IN PLACE. NO REAL IMPROVEMENT SEEN IN CONDITIONS UNTIL
WELL AFTER CHRISTMAS. OVERALL...CIGS WILL BE AOB 3KFT THROUGHOUT
MUCH OF THE WEEK.
&&
.HYDROLOGY...
AS OF 300 AM EST MONDAY
MODELS SHOWING A VERY WET WEEK UPCOMING WITH POTENTIAL FOR
RAINFALL SOMEWHERE IN THE 1 TO POSSIBLY 3 INCH RANGE BY LATER IN
THE WEEK (AND POSSIBLY MORE AFTER THAT) ACROSS THE RIVER BASINS OF
THE HYDROLOGIC SERVICE AREA. DETAILS YET TO BE WORKED OUT...BUT
ENSEMBLE RIVER FORECASTS DO SUGGEST THE POSSIBILITY OF AT LEAST
SOME MINOR RIVER FLOODING. AT THIS POINT BOTH GFS AND NORTH
AMERICAN ENSEMBLES POINTING TOWARD THE DAN RIVER AS THE MOST
LIKELY BASIN FOR FLOODING (AS USUAL THIS EL NINO FALL/WINTER) WITH
UP 70 PERCENT CHANCE FOR MINOR FLOODING AT SOUTH BOSTON FORECAST
POINT AND 30 PERCENT UPSTREAM TO DANVILLE. THESE PERCENTAGES WILL
LIKELY BOUNCE AROUND SOME WITH ENSUING MODEL RUNS AS THE MODELS
CLOSE IN ON A MORE REFINED SOLUTION.
&&
.CLIMATE...
AS OF 945 AM EST SUNDAY...
RECORD HIGH TEMPERATURES
-----------------------------------------------------------------
| | DEC 23 | DEC 24 | DEC 25 | DEC 26 |
| BLACKSBURG | 64 IN 1990 | 62 IN 1996 | 68 IN 1964 | 64 IN 1982 |
| BLUEFIELD | 64 IN 1996 | 66 IN 1964 | 64 IN 1982 | 62 IN 1987 |
| DANVILLE | 67 IN 1998 | 70 IN 1990 | 76 IN 1955 | 75 IN 1982 |
| LYNCHBURG | 70 IN 1933 | 70 IN 1933 | 72 IN 1982 | 72 IN 1922 |
| ROANOKE | 73 IN 1933 | 72 IN 1933 | 68 IN 1982 | 70 IN 1964 |
----------------------------------------------------------------
RECORD HIGHEST MINIMUM TEMPERATURES
-----------------------------------------------------------------
| | DEC 23 | DEC 24 | DEC 25 | DEC 26 |
| BLACKSBURG | 55 IN 1990 | 46 IN 1956 | 41 IN 1972 | 50 IN 1982 |
| BLUEFIELD | 53 IN 1990 | 53 IN 1964 | 55 IN 1982 | 55 IN 1982 |
| DANVILLE | 50 IN 1990 | 53 IN 1990 | 48 IN 1988 | 57 IN 1964 |
| LYNCHBURG | 58 IN 1990 | 47 IN 1979 | 57 IN 1964 | 58 IN 1964 |
| ROANOKE | 58 IN 1990 | 47 IN 1979 | 54 IN 1964 | 56 IN 1982 |
----------------------------------------------------------------
&&
.EQUIPMENT...
AS OF 300 AM EST MONDAY...
A COMMUNICATION OUTAGE HAS LIMITED THE DISTRIBUTION OF THE
OBSERVATION FROM THE BLUEFIELD AUTOMATED SURFACE OBSERVATION
SYSTEM. DATA FROM THIS SITE MAY BE SPORADICALLY UNAVAILABLE. THERE
IS NO ESTIMATE FOR WHEN THIS OUTAGE WILL BE REPAIRED.
IN ADDITION...THE TEMPERATURE/DEWPOINT SENSOR IS OUT OF SERVICE.
TECHNICIANS ARE EXPECTED TO WORK ON THIS TODAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...WP
NEAR TERM...RCS/WP
SHORT TERM...KK
LONG TERM...RCS
AVIATION...RCS
HYDROLOGY...KK/PC
CLIMATE...DS
EQUIPMENT...PM/WP
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1146 AM EST MON DEC 21 2015
.SYNOPSIS...
A DEEP SOUTHERLY FLOW AHEAD OF A COLD FRONT ACROSS THE MISSISSIPPI
VALLEY IS GOING SPREAD MOISTURE OUR WAY THIS AFTERNOON AND
TONIGHT. THE FRONT WEAKENS AND LIFTS NORTH ACROSS THE GREAT LAKES
BY TUESDAY. HOWEVER...ANOTHER FRONT MOVES IN BY MIDWEEK WITH
CONTINUED SOUTHERLY FLOW AND MUCH ABOVE NORMAL TEMPERATURES TO
PROVIDE PERIODS OF MODERATE TO HEAVY RAINFALL.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1145 AM EST MONDAY...
BAND OF LIGHT SHOWERS CONTINUES TO ADVANCE EASTWARD TO THE BLUE
RIDGE. EVEN THOUGH RAIN HAS MOVED ACROSS THE MOUNTAINS...DEW
POINTS ARE NOT RECOVERING VERY QUICKLY. FOR THIS UPDATE..INCREASED
POPS ALONG THE BLUE RIDGE AND FOOTHILL COUNTIES INTO EARLY THIS
AFTERNOON. AGAIN USED THE HRRR FOR THIS UPDATE. ALSO ADJUSTED DEW
POINTS WITH A GRADUAL RISE INTO THIS EVENING.
AS OF 933 AM EST MONDAY...
INCREASED POPS AS LIGHT RAIN CONTINUES TO ADVANCE EASTWARD THIS
MORNING. THE HRRR IS THE ONLY MODEL SEEN SHOWING THIS RAIN ENTER
THE WEST THIS MORNING. HRRR HAS THIS RAIN MOVING EAST OF THE BLUE
RIDGE THIS AFTERNOON...BUT WILL KEEP POPS LOW WITH LOW AND MID
LEVELS BEING DRY VIA MORNING SOUNDING. IF PRECIPITATION DOES PUSH
EAST IT WILL REMAIN LIGHT...POSSIBLY JUST SPRINKLES.
AS OF 223 AM EST MONDAY...
OVERALL SHIFT FROM COLD TO WARM STARTS TODAY. MOISTURE WILL CONTINUE
TO INCREASE AS PWATS OF 1 TO 1.25 INCHES OVER THE TN VALLEY AND GULF
STATES WORK EAST TOWARD THE FORECAST AREA BY THIS EVENING. MODELS
ARE IN GENERAL AGREEMENT ON THE PATTERN BUT SOME DIFFERENCES IN HOW
FAST RAINFALL MOVES IN AND PLACEMENT OF HEAVIER AMOUNTS OVERNIGHT.
BOTH THE NAM/ECM INDICATE A NARROW TONGUE OF MOISTURE ACROSS THE
BLUE RIDGE BY THE END OF THE DAY WITH LIGHT QPF...WHILE THE GFS IS
DRY. WITH MODELS INDICATE SOME UPPER DIVERGENCE AND LOW LVL
CONVERGENCE...DECIDED TO KEEP AT LEAST SLIGHT CHANCE ACROSS THE BLUE
RIDGE THIS AFTERNOON...WITH MOISTURE AND LIFT MORE PREVALENT BY
7PM OVER THE MTNS OF WV/FAR SW VA.
WITH SFC HIGH WELL OFF THE COAST AND MAINLY CLOUDY SKIES HIGHS TODAY
THOUGH MILD WILL BE HELD IN CHECK...RANGING FROM THE UPPER 40S TO
MID 50S.
TONIGHT...SFC FRONT MAKES ITS WAY EAST INTO THE OHIO/TN VALLEY WITH
STRONG FORCING IN THE UPPER LEVELS MOVING ACROSS OUR AREA AFTER
MIDNIGHT. MODELS AGREE IN TWO AREAS OF HIGHER RAINFALL...MAINLY
ALONG THE FRONT FROM MID TN INTO THE OHIO VALLEY AND A SECONDARY
AXIS ACROSS GA/SC INTO THE PIEDMONT OF NC...WITH LIGHTER QPF IN OUR
AREA. THE 0Z NAM IS THE DRIEST FOLLOWED BY THE ECMWF...WITH THE GFS
HAVING MORE QPF. THINK WITH THE FORCING AND SW FLOW AND HIGHER
PWATS...MOST AREAS WILL SEE MEASURABLE RAINFALL SO HAVE AT LEAST
LIKELY IN THE MAJORITY OF THE FORECAST AREA BY DAWN TUESDAY...WITH
CATEGORICAL POPS IN THE MTNS OF WV/FAR SW VA. RAINFALL AMOUNTS
TONIGHT WILL BE A QUARTER INCH OR LESS...THOUGH SOME ISOLATED
POCKETS OF HALF INCH AMOUNTS ARE POSSIBLE. WITH CLOUDS AND
RAIN...PLUS 8H TEMPS OF +10 TO +12C...LOWS WILL BE IN THE 40S...AS
RAIN ALLOWS TEMPS TO FALL TO THE DEWPOINTS IN THE 40S. THOUGH WITH
SW FLOW INCREASING OVER THE HIGHER SLOPES OF WV/FAR SW VA INTO
NC...TEMPS HERE MAY STAY ABOVE 50 THROUGH THE NIGHT.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY NIGHT/...
AS OF 300 AM EST MONDAY...
A DEEP SOUTHWEST FLOW WILL PUMP MOISTURE INTO OUR REGION TUESDAY
INTO WEDNESDAY. UPPER DISTURBANCES ROTATING ALONG THE UPPER FLOW
WILL CONTINUE THE OVERRUNNING SHOWERS. THE GFS AND ECM INDICATED
MAIN SHORTWAVE WILL GENERATE CONVECTION WHICH MOVES EAST ACROSS THE
SOUTHEAST US EARLY TUESDAY...THEN MOVES OFF COAST TUESDAY AFTERNOON
AND EVENING. THIS RESULTS IN DRYING TREND FOR OUR AREA...WITH
MAJORITY OF MOISTURE PUSHED OFF THE COAST. THE NAM SOLUTION IS LESS
AGGRESSIVE WITH THE DRYING IDEA. HIGH TEMPERATURES ON TUESDAY WILL
RANGE FROM THE MID 50S IN THE MOUNTAINS TO THE LOWER 60S IN THE
PIEDMONT.
TUESDAY NIGHT INTO WEDNESDAY...AN UPPER LEVEL TROUGH SWINGS OUT
OF THE ROCKIES AND INTO THE PLAINS. THIS SYSTEM WILL PUSH MORE
WAVES AND GULF MOISTURE INTO THE REGION STARTING LATE TUESDAY NIGHT.
THE NORTH CAROLINA COUNTIES WILL HAVE THE BEST CHANCE OF RAIN
TUESDAY NIGHT. RAIN WILL SPREAD NORTHWARD ALONG THE BLUE RIDGE
HEADING INTO WEDNESDAY MORNING. LOW TEMPERATURES TUESDAY NIGHT WILL
VARY FROM THE MID 40S IN THE NORTHWEST MOUNTAINS TO THE MID 50S IN
THE SOUTHEAST. THE SURFACE WAVE ASSOCIATED WITH THE UPPER TROUGH IS
EXPECTED TO TRACK FROM THE SOUTHERN PLAINS INTO THE GREAT LAKES
REGION BY WEDNESDAY AFTERNOON. PERIODS OF RAIN...HEAVY AT TIMES
EXPECTED WEDNESDAY INTO WEDNESDAY NIGHT. FLOODING PROBLEMS MAY
DEVELOP WHERE THE AXIS OF HEAVY RAIN SETS UP. SEE HYDRO SECTION
FOR MORE DETAILS. RAISED QPF FOR WEDNESDAY WITH AMOUNTS VARYING
FROM 0.65 IN THE NORTHWEST TO AS MUCH AS 3 INCHES ALONG THE
SOUTHERN BLUE RIDGE. HIGH TEMPERATURES ON WEDNESDAY WILL BE AROUND
20 DEGREES ABOVE NORMAL WITH READINGS FROM THE UPPER 50S IN THE
NORTHWEST MOUNTAINS TO AROUND 70 DEGREES IN THE PIEDMONT.
LOW TEMPERATURES WEDNESDAY NIGHT WILL GENERALLY BE IN THE MID 50S IN
THE WEST TO THE LOWER 60S IN THE EAST. THE MILD UNSETTLED WEATHER
CONTINUE THURSDAY INTO THURSDAY NIGHT. THE BEST CHANCE OF RAIN ON
THURSDAY WILL OCCUR IN THE WEST AS SUPPORT BY BOTH GFS AND ECM.
CHRISTMAS EVE WILL BE UNSEASONABLY WARM WITH HIGHS FROM MID 60S IN
THE WEST TO THE MID 70S IN THE EAST. ON THURSDAY NIGHT...SHORTWAVE
SLICES EAST WITH HIGH PRESSURE BUILDING SOUTH OUT OF THE OHIO
VALLEY INTO OUR REGION. LOW TEMPERATURES THURSDAY NIGHT INTO FRIDAY
MORNING WILL DROP INTO THE LOWER 40S IN THE NORTHWEST TO THE MID 50S
IN THE SOUTHEAST.
&&
.LONG TERM /FRIDAY THROUGH SUNDAY/...
AS OF 330 PM EST SUNDAY...
THE LONG RANGE FORECAST FOR THE AREA DIFFERS FROM MODEL TO MODEL.
THE GFS PUSHES THE AXIS OF PRECIPITATION TO THE SOUTHEAST COAST
WITH HIGH PRESSURE BUILDING OVER THE AREA FROM THE NORTH. THE ECM
STALLS A FRONT AND PRECIPITATION OVER THE AREA INTO
FRIDAY...LIFTING IT NORTH WITH THE NEXT SYSTEM COMING OUT OF THE
ROCKIES. THE DIFFERENCES IN THE MODELS LOOKS TO CENTER AROUND AN
UPPER LEVEL RIDGE IN THE WESTERN ATLANTIC. THE GFS IS FARTHER TO
THE EAST WHICH ALLOWS THE RAIN TO MOVE TO THE COAST. AS WITH
NEIGHBORING OFFICES...WILL KEEP LOW POPS IN THE FORECAST FOR
UNCERTAINTY. MODELS CONTINUE TO RETROGRADE THE WESTERN ATLANTIC
RIDGE WESTWARD INTO THE THE GULF. THIS WILL KEEP THE EAST COAST IN
WARM SOUTHERLY FLOW AND A STORM TRACK ACROSS THE OHIO VALLEY. RAIN
CHANCES FOR THIS CHRISTMAS WEEKEND WILL BE HIGHEST IN SOUTHEASTERN
WEST VIRGINIA AND LESS LIKELY ACROSS THE PIEDMONT AND SOUTHSIDE
VIRGINIA.
THE AREA WILL REMAIN ON THE WARM SIDE OF ANY FRONT WITH
TEMPERATURES CONTINUING TO RUN 20F-25F WARMER THAN NORMAL.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
AS OF 640 AM EST MONDAY...
WILL SEE CIGS DROP FROM CIRRUS LEVEL TO SC/AC LEVEL LATER THIS
MORNING INTO THE AFTERNOON. ALREADY GETTING SOME LOW LVL CLOUDS
ARRIVING ALONG SOUTHERLY LOW LVL JET INTO THE TRIAD OF NC INTO
MTV. EXPECT DANVILLE COULD SEE SOME LOW END VFR CIGS BY 15Z...BUT
WILL NOT TAKE THEM BELOW 3KFT.
SPEAKING OF THE LOW LVL JET...ITS STRONG ENOUGH MAINLY 1000 FT
AGL THAT WIND SHEAR WILL BE AN ISSUE AT TIMES THROUGH THE
DAY...AT MOST SITES.
FOR TONIGHT LOOK FOR CIGS TO DROP TO MVFR WITH LIGHT TO MODERATE
RAIN MOVING IN. SOME CIGS WITH A SE WIND INTO THE PIEDMONT AND
BLUE RIDGE ARE EXPECTED TO DROP TO BELOW 1KFT.
.EXTENDED AVIATION DISCUSSION...
GENERALLY POOR AVIATION CONDITIONS EXPECTED THROUGH THE WEEK WITH
MULTIPLE UPPER DISTURBANCES ROTATING NORTHEAST THROUGH THE REGION
FROM A MEAN MID-U.S. DEEP UPPER TROUGH. AT THIS TIME...THE MOST
FAVORABLE PERIODS FOR SUBSTANTIAL RAINFALL AND IFR CIGS/VSBYS WILL
BE MON NIGHT...AND AGAIN TUE NIGHT THROUGH EARLY WED. EVEN WHEN
NOT RAINING...LOW CLOUDS AND DRIZZLE LIKELY WITH VERY MOIST
ATMOSPHERE IN PLACE. NO REAL IMPROVEMENT SEEN IN CONDITIONS UNTIL
WELL AFTER CHRISTMAS. OVERALL...CIGS WILL BE AOB 3KFT THROUGHOUT
MUCH OF THE WEEK.
&&
.HYDROLOGY...
AS OF 300 AM EST MONDAY
MODELS SHOWING A VERY WET WEEK UPCOMING WITH POTENTIAL FOR
RAINFALL SOMEWHERE IN THE 1 TO POSSIBLY 3 INCH RANGE BY LATER IN
THE WEEK (AND POSSIBLY MORE AFTER THAT) ACROSS THE RIVER BASINS OF
THE HYDROLOGIC SERVICE AREA. DETAILS YET TO BE WORKED OUT...BUT
ENSEMBLE RIVER FORECASTS DO SUGGEST THE POSSIBILITY OF AT LEAST
SOME MINOR RIVER FLOODING. AT THIS POINT BOTH GFS AND NORTH
AMERICAN ENSEMBLES POINTING TOWARD THE DAN RIVER AS THE MOST
LIKELY BASIN FOR FLOODING (AS USUAL THIS EL NINO FALL/WINTER) WITH
UP 70 PERCENT CHANCE FOR MINOR FLOODING AT SOUTH BOSTON FORECAST
POINT AND 30 PERCENT UPSTREAM TO DANVILLE. THESE PERCENTAGES WILL
LIKELY BOUNCE AROUND SOME WITH ENSUING MODEL RUNS AS THE MODELS
CLOSE IN ON A MORE REFINED SOLUTION.
&&
.CLIMATE...
AS OF 945 AM EST SUNDAY...
RECORD HIGH TEMPERATURES
-----------------------------------------------------------------
| | DEC 23 | DEC 24 | DEC 25 | DEC 26 |
| BLACKSBURG | 64 IN 1990 | 62 IN 1996 | 68 IN 1964 | 64 IN 1982 |
| BLUEFIELD | 64 IN 1996 | 66 IN 1964 | 64 IN 1982 | 62 IN 1987 |
| DANVILLE | 67 IN 1998 | 70 IN 1990 | 76 IN 1955 | 75 IN 1982 |
| LYNCHBURG | 70 IN 1933 | 70 IN 1933 | 72 IN 1982 | 72 IN 1922 |
| ROANOKE | 73 IN 1933 | 72 IN 1933 | 68 IN 1982 | 70 IN 1964 |
----------------------------------------------------------------
RECORD HIGHEST MINIMUM TEMPERATURES
-----------------------------------------------------------------
| | DEC 23 | DEC 24 | DEC 25 | DEC 26 |
| BLACKSBURG | 55 IN 1990 | 46 IN 1956 | 41 IN 1972 | 50 IN 1982 |
| BLUEFIELD | 53 IN 1990 | 53 IN 1964 | 55 IN 1982 | 55 IN 1982 |
| DANVILLE | 50 IN 1990 | 53 IN 1990 | 48 IN 1988 | 57 IN 1964 |
| LYNCHBURG | 58 IN 1990 | 47 IN 1979 | 57 IN 1964 | 58 IN 1964 |
| ROANOKE | 58 IN 1990 | 47 IN 1979 | 54 IN 1964 | 56 IN 1982 |
----------------------------------------------------------------
&&
.EQUIPMENT...
AS OF 300 AM EST MONDAY...
A COMMUNICATION OUTAGE HAS LIMITED THE DISTRIBUTION OF THE
OBSERVATION FROM THE BLUEFIELD AUTOMATED SURFACE OBSERVATION
SYSTEM. DATA FROM THIS SITE MAY BE SPORADICALLY UNAVAILABLE. THERE
IS NO ESTIMATE FOR WHEN THIS OUTAGE WILL BE REPAIRED.
IN ADDITION...THE TEMPERATURE/DEWPOINT SENSOR IS OUT OF SERVICE.
TECHNICIANS ARE EXPECTED TO WORK ON THIS TODAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...WP
NEAR TERM...RCS/WP
SHORT TERM...KK
LONG TERM...RCS
AVIATION...PC/RAB/WP
HYDROLOGY...KK/PC
CLIMATE...DS
EQUIPMENT...PM/WP
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
941 AM EST MON DEC 21 2015
.SYNOPSIS...
A DEEP SOUTHERLY FLOW AHEAD OF A COLD FRONT ACROSS THE MISSISSIPPI
VALLEY IS GOING SPREAD MOISTURE OUR WAY THIS AFTERNOON AND
TONIGHT. THE FRONT WEAKENS AND LIFTS NORTH ACROSS THE GREAT LAKES
BY TUESDAY. HOWEVER...ANOTHER FRONT MOVES IN BY MIDWEEK WITH
CONTINUED SOUTHERLY FLOW AND MUCH ABOVE NORMAL TEMPERATURES TO
PROVIDE PERIODS OF MODERATE TO HEAVY RAINFALL.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 933 AM EST MONDAY...
INCREASED POPS AS LIGHT RAIN CONTINUES TO ADVANCE EASTWARD THIS
MORNING. THE HRRR IS THE ONLY MODEL SEEN SHOWING THIS RAIN ENTER
THE WEST THIS MORNING. HRRR HAS THIS RAIN MOVING EAST OF THE BLUE
RIDGE THIS AFTERNOON...BUT WILL KEEP POPS LOW WITH LOW AND MID
LEVELS BEING DRY VIA MORNING SOUNDING. IF PRECIPITATION DOES PUSH
EAST IT WILL REMAIN LIGHT...POSSIBLY JUST SPRINKLES.
AS OF 223 AM EST MONDAY...
OVERALL SHIFT FROM COLD TO WARM STARTS TODAY. MOISTURE WILL CONTINUE
TO INCREASE AS PWATS OF 1 TO 1.25 INCHES OVER THE TN VALLEY AND GULF
STATES WORK EAST TOWARD THE FORECAST AREA BY THIS EVENING. MODELS
ARE IN GENERAL AGREEMENT ON THE PATTERN BUT SOME DIFFERENCES IN HOW
FAST RAINFALL MOVES IN AND PLACEMENT OF HEAVIER AMOUNTS OVERNIGHT.
BOTH THE NAM/ECM INDICATE A NARROW TONGUE OF MOISTURE ACROSS THE
BLUE RIDGE BY THE END OF THE DAY WITH LIGHT QPF...WHILE THE GFS IS
DRY. WITH MODELS INDICATE SOME UPPER DIVERGENCE AND LOW LVL
CONVERGENCE...DECIDED TO KEEP AT LEAST SLIGHT CHANCE ACROSS THE BLUE
RIDGE THIS AFTERNOON...WITH MOISTURE AND LIFT MORE PREVALENT BY
7PM OVER THE MTNS OF WV/FAR SW VA.
WITH SFC HIGH WELL OFF THE COAST AND MAINLY CLOUDY SKIES HIGHS TODAY
THOUGH MILD WILL BE HELD IN CHECK...RANGING FROM THE UPPER 40S TO
MID 50S.
TONIGHT...SFC FRONT MAKES ITS WAY EAST INTO THE OHIO/TN VALLEY WITH
STRONG FORCING IN THE UPPER LEVELS MOVING ACROSS OUR AREA AFTER
MIDNIGHT. MODELS AGREE IN TWO AREAS OF HIGHER RAINFALL...MAINLY
ALONG THE FRONT FROM MID TN INTO THE OHIO VALLEY AND A SECONDARY
AXIS ACROSS GA/SC INTO THE PIEDMONT OF NC...WITH LIGHTER QPF IN OUR
AREA. THE 0Z NAM IS THE DRIEST FOLLOWED BY THE ECMWF...WITH THE GFS
HAVING MORE QPF. THINK WITH THE FORCING AND SW FLOW AND HIGHER
PWATS...MOST AREAS WILL SEE MEASURABLE RAINFALL SO HAVE AT LEAST
LIKELY IN THE MAJORITY OF THE FORECAST AREA BY DAWN TUESDAY...WITH
CATEGORICAL POPS IN THE MTNS OF WV/FAR SW VA. RAINFALL AMOUNTS
TONIGHT WILL BE A QUARTER INCH OR LESS...THOUGH SOME ISOLATED
POCKETS OF HALF INCH AMOUNTS ARE POSSIBLE. WITH CLOUDS AND
RAIN...PLUS 8H TEMPS OF +10 TO +12C...LOWS WILL BE IN THE 40S...AS
RAIN ALLOWS TEMPS TO FALL TO THE DEWPOINTS IN THE 40S. THOUGH WITH
SW FLOW INCREASING OVER THE HIGHER SLOPES OF WV/FAR SW VA INTO
NC...TEMPS HERE MAY STAY ABOVE 50 THROUGH THE NIGHT.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY NIGHT/...
AS OF 300 AM EST MONDAY...
A DEEP SOUTHWEST FLOW WILL PUMP MOISTURE INTO OUR REGION TUESDAY
INTO WEDNESDAY. UPPER DISTURBANCES ROTATING ALONG THE UPPER FLOW
WILL CONTINUE THE OVERRUNNING SHOWERS. THE GFS AND ECM INDICATED
MAIN SHORTWAVE WILL GENERATE CONVECTION WHICH MOVES EAST ACROSS THE
SOUTHEAST US EARLY TUESDAY...THEN MOVES OFF COAST TUESDAY AFTERNOON
AND EVENING. THIS RESULTS IN DRYING TREND FOR OUR AREA...WITH
MAJORITY OF MOISTURE PUSHED OFF THE COAST. THE NAM SOLUTION IS LESS
AGGRESSIVE WITH THE DRYING IDEA. HIGH TEMPERATURES ON TUESDAY WILL
RANGE FROM THE MID 50S IN THE MOUNTAINS TO THE LOWER 60S IN THE
PIEDMONT.
TUESDAY NIGHT INTO WEDNESDAY...AN UPPER LEVEL TROUGH SWINGS OUT
OF THE ROCKIES AND INTO THE PLAINS. THIS SYSTEM WILL PUSH MORE
WAVES AND GULF MOISTURE INTO THE REGION STARTING LATE TUESDAY NIGHT.
THE NORTH CAROLINA COUNTIES WILL HAVE THE BEST CHANCE OF RAIN
TUESDAY NIGHT. RAIN WILL SPREAD NORTHWARD ALONG THE BLUE RIDGE
HEADING INTO WEDNESDAY MORNING. LOW TEMPERATURES TUESDAY NIGHT WILL
VARY FROM THE MID 40S IN THE NORTHWEST MOUNTAINS TO THE MID 50S IN
THE SOUTHEAST. THE SURFACE WAVE ASSOCIATED WITH THE UPPER TROUGH IS
EXPECTED TO TRACK FROM THE SOUTHERN PLAINS INTO THE GREAT LAKES
REGION BY WEDNESDAY AFTERNOON. PERIODS OF RAIN...HEAVY AT TIMES
EXPECTED WEDNESDAY INTO WEDNESDAY NIGHT. FLOODING PROBLEMS MAY
DEVELOP WHERE THE AXIS OF HEAVY RAIN SETS UP. SEE HYDRO SECTION
FOR MORE DETAILS. RAISED QPF FOR WEDNESDAY WITH AMOUNTS VARYING
FROM 0.65 IN THE NORTHWEST TO AS MUCH AS 3 INCHES ALONG THE
SOUTHERN BLUE RIDGE. HIGH TEMPERATURES ON WEDNESDAY WILL BE AROUND
20 DEGREES ABOVE NORMAL WITH READINGS FROM THE UPPER 50S IN THE
NORTHWEST MOUNTAINS TO AROUND 70 DEGREES IN THE PIEDMONT.
LOW TEMPERATURES WEDNESDAY NIGHT WILL GENERALLY BE IN THE MID 50S IN
THE WEST TO THE LOWER 60S IN THE EAST. THE MILD UNSETTLED WEATHER
CONTINUE THURSDAY INTO THURSDAY NIGHT. THE BEST CHANCE OF RAIN ON
THURSDAY WILL OCCUR IN THE WEST AS SUPPORT BY BOTH GFS AND ECM.
CHRISTMAS EVE WILL BE UNSEASONABLY WARM WITH HIGHS FROM MID 60S IN
THE WEST TO THE MID 70S IN THE EAST. ON THURSDAY NIGHT...SHORTWAVE
SLICES EAST WITH HIGH PRESSURE BUILDING SOUTH OUT OF THE OHIO
VALLEY INTO OUR REGION. LOW TEMPERATURES THURSDAY NIGHT INTO FRIDAY
MORNING WILL DROP INTO THE LOWER 40S IN THE NORTHWEST TO THE MID 50S
IN THE SOUTHEAST.
&&
.LONG TERM /FRIDAY THROUGH SUNDAY/...
AS OF 330 PM EST SUNDAY...
THE LONG RANGE FORECAST FOR THE AREA DIFFERS FROM MODEL TO MODEL.
THE GFS PUSHES THE AXIS OF PRECIPITATION TO THE SOUTHEAST COAST
WITH HIGH PRESSURE BUILDING OVER THE AREA FROM THE NORTH. THE ECM
STALLS A FRONT AND PRECIPITATION OVER THE AREA INTO
FRIDAY...LIFTING IT NORTH WITH THE NEXT SYSTEM COMING OUT OF THE
ROCKIES. THE DIFFERENCES IN THE MODELS LOOKS TO CENTER AROUND AN
UPPER LEVEL RIDGE IN THE WESTERN ATLANTIC. THE GFS IS FARTHER TO
THE EAST WHICH ALLOWS THE RAIN TO MOVE TO THE COAST. AS WITH
NEIGHBORING OFFICES...WILL KEEP LOW POPS IN THE FORECAST FOR
UNCERTAINTY. MODELS CONTINUE TO RETROGRADE THE WESTERN ATLANTIC
RIDGE WESTWARD INTO THE THE GULF. THIS WILL KEEP THE EAST COAST IN
WARM SOUTHERLY FLOW AND A STORM TRACK ACROSS THE OHIO VALLEY. RAIN
CHANCES FOR THIS CHRISTMAS WEEKEND WILL BE HIGHEST IN SOUTHEASTERN
WEST VIRGINIA AND LESS LIKELY ACROSS THE PIEDMONT AND SOUTHSIDE
VIRGINIA.
THE AREA WILL REMAIN ON THE WARM SIDE OF ANY FRONT WITH
TEMPERATURES CONTINUING TO RUN 20F-25F WARMER THAN NORMAL.
&&
.AVIATION /15Z MONDAY THROUGH FRIDAY/...
AS OF 640 AM EST MONDAY...
WILL SEE CIGS DROP FROM CIRRUS LEVEL TO SC/AC LEVEL LATER THIS
MORNING INTO THE AFTERNOON. ALREADY GETTING SOME LOW LVL CLOUDS
ARRIVING ALONG SOUTHERLY LOW LVL JET INTO THE TRIAD OF NC INTO
MTV. EXPECT DANVILLE COULD SEE SOME LOW END VFR CIGS BY 15Z...BUT
WILL NOT TAKE THEM BELOW 3KFT.
SPEAKING OF THE LOW LVL JET...ITS STRONG ENOUGH MAINLY 1000 FT
AGL THAT WIND SHEAR WILL BE AN ISSUE AT TIMES THROUGH THE
DAY...AT MOST SITES.
FOR TONIGHT LOOK FOR CIGS TO DROP TO MVFR WITH LIGHT TO MODERATE
RAIN MOVING IN. SOME CIGS WITH A SE WIND INTO THE PIEDMONT AND
BLUE RIDGE ARE EXPECTED TO DROP TO BELOW 1KFT.
.EXTENDED AVIATION DISCUSSION...
GENERALLY POOR AVIATION CONDITIONS EXPECTED THROUGH THE WEEK WITH
MULTIPLE UPPER DISTURBANCES ROTATING NORTHEAST THROUGH THE REGION
FROM A MEAN MID-U.S. DEEP UPPER TROUGH. AT THIS TIME...THE MOST
FAVORABLE PERIODS FOR SUBSTANTIAL RAINFALL AND IFR CIGS/VSBYS WILL
BE MON NIGHT...AND AGAIN TUE NIGHT THROUGH EARLY WED. EVEN WHEN
NOT RAINING...LOW CLOUDS AND DRIZZLE LIKELY WITH VERY MOIST
ATMOSPHERE IN PLACE. NO REAL IMPROVEMENT SEEN IN CONDITIONS UNTIL
WELL AFTER CHRISTMAS. OVERALL...CIGS WILL BE AOB 3KFT THROUGHOUT
MUCH OF THE WEEK.
&&
.HYDROLOGY...
AS OF 300 AM EST MONDAY
MODELS SHOWING A VERY WET WEEK UPCOMING WITH POTENTIAL FOR
RAINFALL SOMEWHERE IN THE 1 TO POSSIBLY 3 INCH RANGE BY LATER IN
THE WEEK (AND POSSIBLY MORE AFTER THAT) ACROSS THE RIVER BASINS OF
THE HYDROLOGIC SERVICE AREA. DETAILS YET TO BE WORKED OUT...BUT
ENSEMBLE RIVER FORECASTS DO SUGGEST THE POSSIBILITY OF AT LEAST
SOME MINOR RIVER FLOODING. AT THIS POINT BOTH GFS AND NORTH
AMERICAN ENSEMBLES POINTING TOWARD THE DAN RIVER AS THE MOST
LIKELY BASIN FOR FLOODING (AS USUAL THIS EL NINO FALL/WINTER) WITH
UP 70 PERCENT CHANCE FOR MINOR FLOODING AT SOUTH BOSTON FORECAST
POINT AND 30 PERCENT UPSTREAM TO DANVILLE. THESE PERCENTAGES WILL
LIKELY BOUNCE AROUND SOME WITH ENSUING MODEL RUNS AS THE MODELS
CLOSE IN ON A MORE REFINED SOLUTION.
&&
.CLIMATE...
AS OF 945 AM EST SUNDAY...
RECORD HIGH TEMPERATURES
-----------------------------------------------------------------
| | DEC 23 | DEC 24 | DEC 25 | DEC 26 |
| BLACKSBURG | 64 IN 1990 | 62 IN 1996 | 68 IN 1964 | 64 IN 1982 |
| BLUEFIELD | 64 IN 1996 | 66 IN 1964 | 64 IN 1982 | 62 IN 1987 |
| DANVILLE | 67 IN 1998 | 70 IN 1990 | 76 IN 1955 | 75 IN 1982 |
| LYNCHBURG | 70 IN 1933 | 70 IN 1933 | 72 IN 1982 | 72 IN 1922 |
| ROANOKE | 73 IN 1933 | 72 IN 1933 | 68 IN 1982 | 70 IN 1964 |
----------------------------------------------------------------
RECORD HIGHEST MINIMUM TEMPERATURES
-----------------------------------------------------------------
| | DEC 23 | DEC 24 | DEC 25 | DEC 26 |
| BLACKSBURG | 55 IN 1990 | 46 IN 1956 | 41 IN 1972 | 50 IN 1982 |
| BLUEFIELD | 53 IN 1990 | 53 IN 1964 | 55 IN 1982 | 55 IN 1982 |
| DANVILLE | 50 IN 1990 | 53 IN 1990 | 48 IN 1988 | 57 IN 1964 |
| LYNCHBURG | 58 IN 1990 | 47 IN 1979 | 57 IN 1964 | 58 IN 1964 |
| ROANOKE | 58 IN 1990 | 47 IN 1979 | 54 IN 1964 | 56 IN 1982 |
----------------------------------------------------------------
&&
.EQUIPMENT...
AS OF 300 AM EST MONDAY...
A COMMUNICATION OUTAGE HAS LIMITED THE DISTRIBUTION OF THE
OBSERVATION FROM THE BLUEFIELD AUTOMATED SURFACE OBSERVATION
SYSTEM. DATA FROM THIS SITE MAY BE SPORADICALLY UNAVAILABLE. THERE
IS NO ESTIMATE FOR WHEN THIS OUTAGE WILL BE REPAIRED.
IN ADDITION...THE TEMPERATURE/DEWPOINT SENSOR IS OUT OF SERVICE.
TECHNICIANS ARE EXPECTED TO WORK ON THIS TODAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...WP
NEAR TERM...RCS/WP
SHORT TERM...KK
LONG TERM...RCS
AVIATION...PC/RAB/WP
HYDROLOGY...KK/PC
CLIMATE...DS
EQUIPMENT...PM/WP
AREA FORECAST DISCUSSION...UPDATED
NWS CHEYENNE WY
758 PM MST TUE DEC 22 2015
.UPDATE...
ISSUED AT 758 PM MST TUE DEC 22 2015
ALLOWED WINTER WEATHER ADVISORIES FOR THE ELK MOUNTAIN...
ARLINGTON...AND SOUTHWESTERN CARBON COUNTY TO EXPIRE EARLIER THIS
EVENING GIVEN MOST OF ANY SIGNIFICANT SNOWFALL WILL BE TO THE EAST
AND WINDS HAVE RELAXED TO WHERE BLOWING SNOW ISSUES ARE NOT
EXPECTED TO BE SIGNIFICANT. WYDOT STILL REPORTS SOME ROADS AS
SLICK OR SLICK IN SPOTS SO MOTORISTS WILL NEED TO BE ADVISED TO
CHECK THE LATEST ROAD CONDITIONS BEFORE HEADING OUT. WINTER STORM
WARNINGS REMAIN POSTED FOR MORE HEAVY SNOW POTENTIAL THROUGH
TOMORROW IN THE SIERRA MADRE AND SNOWY MOUNTAIN RANGES WEST OF
LARAMIE.
BAND OF LIGHT SNOW EXTENDS FROM NORTHEASTERN COLORADO INTO THE
SOUTHERN NEBRASKA PANHANDLE. A LOT OF THE RADAR RETURNS MAY NOT BE
MAKING IT TO THE SURFACE...AND THE DEEPER MOISTURE AND HIGHER
CLOUDTOP SIGNATURES ARE MOVING OUT EAST OF CHEYENNE WITH MOST OF
ANY LIGHT TO MODERATE SNOW EXPECTED TO AFFECT THE SOUTHERN
NEBRASKA PANHANDLE...AND RIGHT NOW IT DOESN`T LOOK LIKE THEY WILL
GET MUCH IN THE WAY OF NEW SNOW THIS EVENING OR OVERNIGHT GIVEN
OBSERVATIONS AND RADAR AND SATELLITE RETURNS. THEREFORE WILL KEEP
A CHANCE OF SNOW GOING SOUTHERN NEBRASKA PANHANDLE TO
CHEYENNE...BUT IT ISN`T LOOKING LIKE A FEW INCHES WILL PAN OUT IN
CHEYENNE...MAYBE AN INCH OR SO SIDNEY (LIKELY AT MOST) IF WE GET
ANOTHER BAND DEVELOP TO THE SOUTHWEST AND MOVE ACROSS THEM LATE
TONIGHT.
BASED ON THE CHANCES OF SNOW WE CURRENTLY HAVE ADVERTISED OUT WEST
ACROSS PARTS OF CARBON COUNTY AND ALONG I-80 FROM RAWLINS TO
LARAMIE FOR TOMORROW...WE MAY HAVE TO POST WINTER WEATHER
ADVISORIES AGAIN ON THE EARLY MORNING SHIFT FOR TOMORROW IF NEW
SNOW AMOUNTS COME IN A BIT HIGHER ON OVERNIGHT MODEL RUNS
RESULTING IN A HIGHER POTENTIAL FOR SIGNIFICANT TRAVEL IMPACTS.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 214 PM MST TUE DEC 22 2015
PRIMARY FORECAST CONCERN FOR THE SHORT TERM IS THE POTENTIAL FOR
SNOWFALL ACROSS THE EXTREME SE WYOMING PLAINS EXTENDING INTO THE
SOUTHERN NEBRASKA PANHANDLE THIS EVENING AND TONIGHT. EVERYTHING
ELSE APPEARS ON TRACK...WITH CURRENT KCYS RADAR LOOP SHOWING
SNOWFALL CONTINUING OVER THE MOUNTAINS. SNOTEL OBSERVATIONS ACROSS
THE SIERRA MADRE RANGE SHOW SOME IMPRESSIVE 36 HOUR SNOW
TOTALS...WITH TWO LOCATIONS NEAR BATTLE MOUNTAIN PASS ESTIMATING
BETWEEN 34 TO 42 INCHES OF SNOW SINCE LATE SUNDAY NIGHT. MORE SNOW
IS EXPECTED TONIGHT AND WEDNESDAY...SO THESE TOTALS WILL LIKELY GO
OVER 4 FEET IN A FEW LOCATIONS. MUCH LESS SNOW WAS OBSERVED OVER
THE SNOWY RANGE WITH ONLY ONE LOCATION ABOVE ONE FOOT OF TOTAL
ACCUMULATION. WILL CONTINUE THE WINTER WEATHER ADVISORIES FOR A
FEW OF THE LOWER ELEVATIONS OF CARBON COUNTY INTO THIS EVENING
WITH SOME ADDITIONAL SNOW AND BLOWING SNOW ALONG AND SOUTH OF I80.
ATTENTION THEN SHIFTS EASTWARD TOWARDS LARAMIE...THE CHEYENNE
AREA...AND ACROSS THE SOUTHERN NE PANHANDLE ALONG I80. MODELS ARE
IN PRETTY GOOD AGREEMENT SHOWING AN AREA OF RAPID FRONTOGENESIS
THIS EVENING JUST SOUTH OF THE COLORADO BORDER. MODELS SHOW A
WEAK WAVE OF LOW PRESSURE DEVELOPING ALONG THE FRONT THIS
EVENING...WHICH IS CURRENTLY NEAR DENVER AND STRETCHES EASTWARD
OVER THE PLAINS NEAR I-70 OVER EASTERN COLORADO. THIS FEATURE
APPEARS TO BE FAST MOVING BUT POTENT...WITH EVEN THE HRRR AND NAM
SHOWING SOME MODERATE SNOW FROM THE I80 SUMMIT EASTWARD INTO
THE SOUTHERN NE PANHANDLE. TYPICALLY...GOOD MODEL AGREEMENT WOULD
INCREASE OVERALL CONFIDENCE 6 TO 12 HOURS OUT...BUT THE ISSUE IS
NO MODELS WAS SHOWING THIS FEATURE YESTERDAY. FOR NOW...INCREASED
POP TO 50 PERCENT ALONG THE I80 CORRIDOR INTO SIDNEY NEBRASKA.
WORDED FORECAST FOR OCCASIONAL SNOW AND 1 TO 2 INCHES OF SNOW
ACCUMULATION FOR NOW EVEN THOUGH THE NAM AND GEM ARE A BIT HIGHER.
WITH WESTERLY FLOW JUST OFF THE SURFACE AND RELATIVELY LOW
DEWPOINTS...CONCERNED THERE IS TOO MUCH DRY AIR TO PRODUCE MUCH
SNOWFALL. THE FRONT WILL QUICKLY PUSH SOUTH AND EAST LATE TONIGHT.
ANOTHER ROUND OF SNOW IS POSSIBLE FOR WEDNESDAY...ALTHOUGH MODELS
ARE NOT AS AGGRESSIVE AS THEY WERE YESTERDAY. ANOTHER QUICK MOVING
SHORTWAVE MOVES ACROSS WYOMING DURING THE AFTERNOON AND EVENING
HOURS...WITH SOME LIGHT SNOW ACROSS THE MOUNTAINS AND POTENTIALACROSS
THE EASTERN PLAINS. WINDS WILL ALSO BEGIN TO INCREASE AGAIN LATE
WEDNESDAY AND WEDNESDAY NIGHT AS HIGH PRESSURE NEAR THE SURFACE
BUILDS ON THE WINDWARD SIDE OF THE ROCKY MOUNTAINS. MAY NEED HIGH
WIND HEADLINES FOR THE WIND PRONE AREAS ONCE AGAIN BY EARLY
THURSDAY MORNING WITH GUSTS AROUND 55 TO 60 MPH.
OTHERWISE...BECOMING COLDER EACH DAY WITH HIGHS ON IN THE 20S TO
LOW 30S BY CHRISTMAS EVE.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 245 PM MST TUE DEC 22 2015
NEXT UPPER SYSTEM TO AFFECT THE AREA WILL BE DIGGING OVER THE
WESTERN CONUS THURSDAY NIGHT WITH SW FLOW ALOFT OVER THE CWA. SOME
SNOW SHOWERS SHOULD OCCUR OVER THE HIGHER MTNS THURSDAY NIGHT AS
MOISTURE INCREASES IN THE FLOW OVER THAT AREA. ONE BATCH OF ENERGY
EJECTS NORTHEAST ACROSS THE CWA CHRISTMAS DAY WITH LEE
CYCLOGENESIS OVER SE COLORADO. THIS SHOULD BRING AN AREA OF LIGHT
SNOW TO MUCH OF THE CWA IN THE AFTERNOON AND EVENING BODING FOR A
WHITE CHRISTMAS FOR AT LEAST PARTS OF THE CWA FOR THE 4TH TIME IN
THE LAST 5 YEARS. MEANWHILE THE MAIN ENERGY WITH THE UPPER SYSTEM
STILL PROGGED TO CUT OFF OVER ARIZONA FRIDAY NIGHT WHILE THE SNOW
ENDS OVER OUR CWA. MODELS IN PRETTY GOOD AGREEMENT IN TRACKING THE
UPPER LOW ACROSS THE SOUTHERN ROCKYS INTO THE SOUTHERN PLAINS
SATURDAY THROUGH SUNDAY WITH THE GFS A BIT FASTER. THIS KEEPS THE
CWA DRY BUT COLD COMPLIMENTS OF A COLD SFC HIGH THAT WILL SETTLE
OVER THE NORTHERN PLAINS. THE UPPER LOW THEN LIFTS NORTHEAST ON
MONDAY AND MAY BRING A GLANCING SHOT OF WRAP-AROUND LIGHT SNOW TO
THE PANHANDLE. OTHERWISE WARMING SOME MONDAY AS SFC DOWNSLOPE FLOW
SETS UP BEFORE ANOTHER UPPER SHORTWAVE PASSES BY MONDAY NIGHT
BRINGING SOME COOLER AIR AGAIN AS WELL AS SOME MTN SNOW SHOWERS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY AFTERNOON)
ISSUED AT 245 PM MST TUE DEC 22 2015
MAINLY VFR OVER ALL TERMINALS INTO EARLY THIS EVENING THEN SOME
MVFR/IFR CONDITIONS EXPECTED FOR A TIME TONIGHT ALONG A LINE FROM
KRWL TO KSNY AS A BAND OF LIGHT SNOW MAY DEVELOP. CONDITIONS
IMPROVING LATER TONIGHT IN THAT AREA. VFR AGAIN AREAWIDE
WEDNESDAY.
&&
.FIRE WEATHER...
ISSUED AT 214 PM MST TUE DEC 22 2015
NO FIRE WEATHER CONCERNS IN THE NEAR FUTURE WITH AFTERNOON
HUMIDITY VALUES WELL OUTSIDE OF CRITICAL THRESHOLDS IN ADDITION TO
SEVERAL CHANCES FOR PRECIPITATION OVER THE NEXT SEVERAL DAYS.
HEAVY MOUNTAIN SNOW IS ALREADY OCCURRING IN THE SNOWY/SIERRA
MADRES...AND IS LIKELY TO CONTINUE THROUGH THU.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...WINTER STORM WARNING UNTIL 5 PM MST WEDNESDAY FOR WYZ112-114.
NE...NONE.
&&
$$
UPDATE...JG
SHORT TERM...TJT
LONG TERM...RE
AVIATION...RE
FIRE WEATHER...TJT
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
956 PM MST TUE DEC 22 2015
.SYNOPSIS...
PACIFIC MOISTURE WILL SPREAD ACROSS THE REGION THROUGH THE WEEK
RESULTING IN PERIODS OF CLOUDINESS AND CHANCES FOR
PRECIPITATION...MAINLY NORTH AND EAST OF PHOENIX. THE BEST CHANCES
FOR RAIN APPEAR TO BE TONIGHT INTO WEDNESDAY AND AGAIN THURSDAY INTO
CHRISTMAS. WHILE THESE SYSTEMS DO NOT LOOK VERY WET...THEY COULD MAKE
FOR DIFFICULT TRAVEL CONDITIONS ACROSS NORTHERN ARIZONA. TEMPERATURES
WILL REMAIN NEAR NORMAL BUT ARE EXPECTED TO DROP LATE IN THE WEEK AND
INTO THE WEEKEND AS A STRONG AND COLD LOW PRESSURE SYSTEM AFFECTS THE
DESERT SOUTHWEST. SOME GUSTY DAYTIME WINDS AND SUB FREEZING NIGHTTIME
TEMPERATURES WILL BE POSSIBLE OVER THE WEEKEND FOR THE LOWER DESERTS.
&&
.DISCUSSION...
LOW STRATUS HAS BEEN QUITE PERSISTENT OVER SOUTH-CENTRAL ARIZONA
TODAY THROUGH THIS EVENING. PRECIP THIS AFTERNOON AND EVENING HAS
BEEN VERY MODEST...LIMITED TO SOME DRIZZLE AND SPOTTY LIGHT
SHOWERS...MOSTLY EAST OF THE METRO. SATELLITE IMAGERY INDICATES LOWER
CLOUDINESS HAS DECREASED OVER SOUTHWEST ARIZONA...NAMELY LA PAZ
COUNTY. THIS FITS THE MODEL PROJECTIONS. FOR SOUTH-CENTRAL ARIZONA
HOWEVER...MODELS ALSO SHOW LOW CLOUDS LINGERING THROUGH AT LEAST
WEDNESDAY MORNING IF NOT INTO THURSDAY. IN FACT...THEY INDICATE
CEILINGS WILL GET EVEN LOWER TONIGHT AND WEDNESDAY MORNING. OF
NOTE...THE RAP HAS BEEN INDICATING A BREAKUP OF THE OVERCAST STARTING
AS EARLY AS 08-09Z BUT STILL KEEPING AT LEAST SCATTERED LOW CLOUDS.
THE NAM AND GFS CONTINUE TO BE MORE PESSIMISTIC. WE WILL PROBABLY
SEE SOME SPOTS WITH HAZE/MIST BUT WITHOUT MORE RAPID CLEARING AND
WITHOUT PRECIP ON THE GROUND...IT WILL BE HARD TO GET DENSE FOG ON
THE LOWER DESERTS. FORECAST SOUNDINGS ALSO SUPPORT THIS. NOT SO FOR
HIGHER TERRAIN THOUGH. MAY NEED TO INSERT MENTION OF FOG FOR OUR
HIGHER TERRAIN FORECAST ZONE TONIGHT. AS THE MOISTURE LAYER GETS EVEN
MORE SHALLOW OVERNIGHT...SHOWERS/DRIZZLE WILL LIKELY TAPER OFF AFTER
09Z OR SO. THERE ARE SOME INDICATIONS OF AN INCREASE IN MOISTURE
DEPTH DURING THE DAY WEDNESDAY ALONG WITH SOME LIFT SO WILL HOLD ON
TO POPS.
&&
.PREVIOUS DISCUSSION...ISSUED 253 PM MST/153 PM PST...
LATEST VISIBLE SATELLITE SHOWS WIDESPREAD THICK STRATOCU AND
NUMEROUS AREAS OF MOUNTAIN WAVE CLOUDINESS ACROSS AZ. LATEST RADAR
CONTINUES TO SHOW BACKBUILDING LIGHT RAIN AND SPRINKLES ACROSS
NORTHERN MARICOPA COUNTY...INCLUDING PORTIONS OF THE PHOENIX AREA.
DESPITE THE PRESENCE OF A 100+ KT 250 MB JET...VORTICITY AND JET-
FORCED ASCENT REMAIN RELATIVELY WEAK. LIGHT PRECIPITATION APPEARS TO
BE MORE A RESULT OF THE SUFFICIENT MOISTURE TRANSPORT FROM THE
REMNANT ATMOSPHERIC RIVER COUPLED WITH ANOMALOUSLY STRONG MID-LEVEL
FLOW AND SUBSEQUENT OROGRAPHIC INFLUENCES. 500 MB WIND SPEEDS ARE NOT
EXACTLY OFF THE CHART...BUT CLOSE TO THE 90TH PERCENTILE PER THE SPC
SOUNDING CLIMATOLOGY AND NAEFS PERCENTILES.
THE THICK CLOUDINESS HAS INHIBITED INSOLATION AND TEMPERATURES HAVE
STRUGGLED TO GET THROUGH THE LOWER-MID 50S...STILL WELL ABOVE THE
RECORD LOW MAXIMUM OF 46 DEGREES IN PHOENIX. HI-RES WRFS ALONG WITH
THE NCAR ENSEMBLE AND LATEST RUNS OF THE HRRR INDICATE THAT THE
LIGHT PRECIP WILL GRADUALLY WORK EASTWARD INTO GILA COUNTY TONIGHT AND
EVENTUALLY SOUTHWARD TOWARDS PINAL COUNTY. ANY RAIN THAT DEVELOPS
WILL LIKELY ONLY AMOUNT TO A FEW HUNDREDTHS OF AN INCH AT MOST IN THE
LOWER DESERTS.
LATEST GFS AND ECMWF REMAIN IN GOOD AGREEMENT THE NEXT FEW
DAYS...INDICATING THAT THE MOIST NORTHWESTERLY FLOW WILL PERSIST.
TREND HAS BEEN A LITTLE BIT FURTHER TO THE EAST ACROSS THE HIGHER
TERRAIN OF MARICOPA AND GILA COUNTIES WITH REGARD TO THE BEST CHANCE
OF PRECIP. CONSEQUENTLY...FORECAST POPS HAVE BEEN REFINED TO DECREASE
VALUES FURTHER WEST AND INCREASE THEM ACROSS GILA COUNTY...IN LINE
WITH THE VALUES FROM THE LATEST GEFS REFORECAST CALIBRATED TO CLIMO.
LATEST MULTI-MODEL ENSEMBLE MEDIAN ALSO SUGGESTS THAT STORM TOTALS
ACROSS THE HIGHER TERRAIN OF GILA COUNTY COULD REACH A HALF OF AN
INCH THROUGH CHRISTMAS EVE. NO SIGNIFICANT CHANGES WERE MADE TO THE
TEMPERATURES...WHICH REMAIN AT OR BELOW NORMAL.
&&
.PREVIOUS DISCUSSION...
THE NEXT BETTER ORGANIZED SYSTEM WILL DEVELOP OUT OF THE GULF OF
ALASKA AND ARRIVE INTO OUR AREA LATE THURSDAY AND INTO FRIDAY. THIS
PARTICULAR SYSTEM WILL QUICKLY MOVE INTO THE AREA AND CUT-OFF FROM
THE MAIN STORM TRACK WHILE BRINGING A SIGNIFICANT COLD POOL AND
FORCING INTO THE REGION. TIGHT INTERSECTION OF FRONTOGENETICAL
FORCING AND MOISTURE BEFORE DRIER AIR BEGINS TO WRAP INTO THE AREA
FROM THE NORTH LIMITS PRECIPITATION AGAIN MAINLY ACROSS
NORTHERN/EASTERN AZ...EVEN LIMITING PRECIP CHANCES FOR THE PHX AREA
COME FRIDAY AND INTO SATURDAY. WITH THE SYSTEM LOOKING TO BE VERY
COLD...500 MB TEMPS AT -31C/700 MB TEMPS AT -14C AND 850 TEMPS AT -
2.5C ALL POSSIBLE UNDER THE STRONGER SCENARIOS...SNOW LEVELS WILL
DROP TO 3000 FEET OR POSSIBLY LOWER. THUS THE BIGGEST IMPACT WILL
LIKELY BE FOR TRAVELERS INTO OR ACROSS THE HIGHER ELEVATIONS AREAS OF
AZ. STRONG FUNNELING WINDS ALONG THE EASTERN FRINGE OF THE
SUBTROPICAL PACIFIC RIDGE AND THE DEPARTING CUT-OFF LOW WILL LEAD TO
WINDY CONDITIONS ALONG THE CO RIVER VALLEY FOR SATURDAY. LINGERING
INTO SUNDAY STRONG GUSTY WINDS FROM THE NORTH MAY CAUSE DIFFICULT
TRAVEL PERIODS FOR MOTORISTS ALONG EAST-WEST ORIENTED
ROADWAYS...INCLUDING INTERSTATE 8/10.
CLEARING SKIES...STRONG SURFACE HIGHS AND REINTRODUCTION OF THE
SIGNIFICANTLY COLDER AIRMASS WILL LEAD VERY COOL WEEKEND DAYTIME
TEMPERATURES AS WELL AS ANOTHER ROUND OF FREEZING OR SUB-FREEZING
TEMPERATURES FOR SOME OUTLYING LOWER ELEVATION DESERTS SATURDAY AND
SUNDAY MORNINGS. FOR THE EARLY NEXT WEEK...SOME DISCREPANCY REMAINS
BETWEEN THE DETERMINISTIC AND ENSEMBLE SUITES WITH THE TIMING OF
SHORTWAVE RIDGING AND ADDITIONAL LOW PRESSURE FEATURES PASSING
THROUGH THE REGION. AT THE MOMENT THOUGH WITH THE RE-ESTABLISHED DRY
AIRMASS AND LOSS OF ENHANCED MOISTURE FLOW FROM OFF THE NORTHEASTERN
PACIFIC THESE LOW PRESSURE WAVES APPEAR TO LACK MUCH BY WAY OF
PRECIP FOR THE FORECAST AREA AHEAD OF THE NEW YEAR`S HOLIDAY.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
RATHER MOIST LOWER TROPOSPHERE FOR CIGS THIS EVENING AT
5-7 KFT MSL WITH ISOLATED-SCT SHOWERS/DRIZZLE. HIGHER MOUNTAINS
OBSCURED. THOUGH SHOWERS EXPECTED TO DISSIPATE AFT 06Z CIGS WILL
LOWER FURTHER TO 3-5 KFT MSL BY 10-12Z WITH AREAS OF HAZE/MIST
REDUCING VSBYS BELOW 6SM...LOCALLY 4SM. LOWER MOUNTAIN TOPS OBSCURED.
CONDITIONS EXPECTED TO IMPROVE SIGNIFICANTLY AFTER 17-19Z. OF
NOTE...SOME MODEL GUIDANCE DEPICTS CEILINGS GOING SCATTERED AFT 09Z
BUT MAJORITY DOES NOT. SURFACE WINDS REMAIN LIGHT FAVORING EAST BUT
ABOVE THE SURFACE...WESTERLY WINDS PREVAIL.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
SURFACE WINDS WILL FAVOR WESTERLY DIRECTIONS WEST OF THE LOWER
COLORADO RIVER VALLEY AND SOUTHERLY DIRECTIONS NEAR AND EAST OF THE
VALLEY. SPEEDS WILL BE STRONGER WEST OF THE LOWER COLORADO RIVER
VALLEY BUT WILL GENERALLY DECREASE TO NEAR 10 KTS. STRONG WESTERLY
FLOW WILL CONTINUE ABOVE THE SURFACE...FLIRTING WITH LLWS CRITERIA
UNTIL ABOUT 17-18Z. AS FOR CLOUDS...CIRRUS WILL CONTINUE TO DECLINE
AS WILL LOWER CLOUDS EAST OF THE RIVER VALLEY. WIND SPEEDS PICK UP
AGAIN WEDNESDAY AFTERNOON BUT NOT AS STRONG AS TUESDAY.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
THURSDAY THROUGH MONDAY...
A LOW PRESSURE SYSTEM WILL AFFECT THE DISTRICTS INTO THE WEEKEND...
BRINGING WIDELY SCATTERED DESERT RAIN AND MOUNTAIN SNOW SHOWERS FROM
MARICOPA COUNTY EASTWARD...WITH SOUTHWEST ARIZONA AND SOUTHEAST
CALIFORNIA DESERTS REMAINING DRY. AS THE LOW MOVES THROUGH THE
REGION...WINDS WILL INCREASE OUT OF THE NORTH-NORTHWEST WITH GUSTS
UP TO 40 MPH POSSIBLE ACROSS SOUTHEAST CALIFORNIA AND ALONG THE
LOWER COLORADO RIVER VALLEY SATURDAY. MUCH LESS WIND ALONG WITH
DRIER CONDITIONS ARE EXPECTED AREA-WIDE SUNDAY AS THE UPPER LOW
SHIFTS OFF TOWARDS THE EAST. MUCH DRIER AIR WILL SPREAD INTO THE
AREA BEHIND THE DEPARTING LOW...WITH MINIMUM HUMIDITY VALUES
DROPPING BACK INTO THE TEENS OVER MUCH OF SOUTHEAST CALIFORNIA AND
THE SOUTHWEST ARIZONA DESERTS INTO EARLY NEXT WEEK.
&&
.SPOTTER INFORMATION STATEMENT...
SPOTTERS ARE ENCOURAGED TO REPORT BASED ON STANDARD OPERATING
PROCEDURES.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...AJ
PREVIOUS DISCUSSION...HIRSCH/NOLTE
AVIATION...AJ
FIRE WEATHER...CB/MEYERS
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1259 AM MST WED DEC 23 2015
.UPDATE...
ISSUED AT 1249 AM MST WED DEC 23 2015
WITH CLEARING SKIES BEHIND TONIGHTS SNOW BAND THAT CONTINEUS TO
MARCH EAST ACROSS THE PLAINS...AREAS OF THICK FOG ARE FORMING.
HAVE ADDED THESE AREAS OF THICKER FOG TO THE FORECAST...THOUGH
HIRES MODELS WANT TO KEEP IT MAINLY NORTH OF THE DENVER METRO
AREA. HIRES MODELS ALSO PERSISTENT IN BRINGING ANOTHER BATCH OF
SNOW SHOWERS TO THE METRO AREAS AFTER 4AM...ORIGINATING FROM THE
CURRENTBATCH OF SHOWERS ACROSS NORTHWESTERN COLORADO. ADDED A
SLIGHT CHANCE FOR THE METRO AREAS THEN PUSHING EAST FROM 4AM UNTIL
7AM. NOT EXPECTING MUCH ACCUMULATION AS THE BEST DYNAMICS HAVE
PUSHED EAST.
HAVE ALSO REMOVED CHANCES FOR SHOWERS FOR MOST OF WEDNESDAY AFTERNOON
FOR THE PLAINS. EVEN THOUGH THE AIRMASS SHOULD BE
UNSTABLE...DOWNSLOPING LOOKS TO OVERRIDE THIS. COULD STILL SEE A
CHANCE TO SEE SHOWERS MAINLY IN THE EVENING HOWEVER.
UPDATE ISSUED AT 1010 PM MST TUE DEC 22 2015
RAPID ZONAL FLOW ALOFT EQUATES TO RAPID CHANGES IN OUR WEATHER
CONDITIONS THIS EVENING. BANDED SNOWFALL HANGING OVER NORTHERN
PORTIONS OF THE CWA ALL EVENING HAS MADE LITTLE SOUTHWARD PROGRESS
AS MESOSCALE MODELS INDICATED. ALTHOUGH IN THE PAST HOUR THE TAIL
END OF THIS SNOW BAND OVERT THE FRONT RANGE HAS SHOWN SIGNS OF
ADVANCING SOUTHWARD IN RESPONSE TO THE NEXT INFLUX OF PACIFIC
MOISTURE SPREADING INTO THE NORTH CENTRAL MTNS AT THIS HOUR.
SNOWFALL RATES UNDER THE SNOW BAND NORTH OF DENVER IN THE 0.5 TO 1
INCH PER HOUR RATE. SHOULD SEE SIMILAR SNOWFALL RATES DEVELOPING
THE HIGH COUNTRY OVER THE NEXT HOUR OR TWO...WITH POSSIBLY GREATER
RATES OVER THE HIGH TERRAIN IN SUMMIT AND WESTERN PARK COUNTIES.
HRRR AND RAP INDICATE THE HIGHEST 6-HR SNOW TOTALS ON THE PLAINS
ACROSS MORGAN...WASHINGTON AND LOGAN COUNTIES WHERE 1-3 INCH
AMOUNTS ARE POSSIBLE. CLOSER TO THE FRONT RANGE COULD ANOTHER
INCH OR TWO FROM DENVER NORTHWARD AND PERHAPS AND INCH OR SO IN
THE DENVER AREA BEFORE 10Z TONIGHT...THAT`S ASSUMING A SNOW BAND
FORMS FARTHER SOUTH AS THE HRRR AND RAP INDICATE. SHOULD SEE LIGHT
TO MODERATE SNOWFALL REST OF TONIGHT IN THE HIGH COUNTRY WHERE WE
COULD SEE ANOTHER 3-5 INCHES ON WEST FACING SLOPES BY MORNING.
UPDATED FORECAST WITH THESE CHANGES ALREADY OUT.
UPDATE ISSUED AT 748 PM MST TUE DEC 22 2015
SNOW OVER LARIMER AND WELD COUNTIES WILL TO SPREAD SOUTH AND EAST
THROUGH THE EVENING AND OVERNIGHT HOURS. THE 00Z SOUNDING SHOWED A
NEARLY DRY ADIABATIC LAPSE RATE FROM 750MB UP TO 300 MB...SO
HEAVY CONVECTIVE SNOW WILL REMAIN POSSIBLE WITH BRIEF SNOWFALL
RATES OF 1 TO 2 INCHES PER HOUR POSSIBLE. AN ESTIMATED HALF INCH
HAS FALLEN IN FORT COLLINS SO FAR BASED ON WEB CAMERAS. INCREASED
POPS AND SNOWFALL AMOUNTS EARLIER AND THEY STILL APPEAR ON TRACK.
UPDATE ISSUED AT 518 PM MST TUE DEC 22 2015
LATEST SHORT RANGE MODELS AND 18Z MODELS SHOWING MORE SNOW FOR
NORTHEAST COLORADO TONIGHT. FAVORABLE SIDE OF THE JET WILL BE OVER
THE AREA. IN ADDITION...AIRMASS WILL BE UNSTABLE WITH LAPSE RATES
OF 6 TO 8.5 C/KM. LATEST RADAR SHOWING INCREASING RETURNS...MOST
OF WHICH IS VIRGA OVER LARIMER AND WELD COUNTIES. AIRMASS WILL
CONTINUE TO MOISTEN AND EXPECT SNOW TO INCREASE THROUGH THE
EVENING HOURS. UPDATED TO INCREASE POPS INTO THE LIKELY RANGE.
MOST AREAS WILL SEE LIGHT SNOWFALL...AN INCH OR LESS. HOWEVER A
FEW SNOW BANDS WILL BE POSSIBLE WHERE UP TO 3 INCHES MAY FALL.
TEMPERATURES WILL BE IN THE UPPER 20S TO LOWER 30S. SO ROADS WILL
BE SLOW TO ICE UP EXCEPT UNDER THE HEAVIER SNOW BANDS. THIS
SYSTEM WILL BE QUICK MOVING AND BE OUT OF THE AREA BY SUNRISE.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 142 PM MST TUE DEC 22 2015
A BROAD UPPER LEVEL TROUGH CONTINUES TO BRING INCREASED MOISTURE
AND STRONG WNW WINDS INTO THE MOUNTAINS. SNOW SHOWERS AND GUSTY
WINDS WILL CONTINUE OVER THE MOUNTAINS THROUGH THE EVENING HOURS
BEFORE DIMINISHING OVERNIGHT. TOTAL ACCUMULATIONS WILL BE 8 TO 18
INCHES WITH THE HIGHER AMOUNTS OVER THE NORTHERN MOUNTAINS ON WEST
FACING SLOPES. AREAS NEAR THE PARK AND GORE RANGES IN THE NE
PORTIONS OF THE CWA COULD SEE UP TO 2 FEET ON WEST FACING SLOPES
THROUGH TOMORROW AFTERNOON. ON THE PLAINS THE SURFACE LOW THAT HAS
BEEN KEEPING SNOW OUT OF THE PICTURE WILL MOVE OFF TO THE SOUTH
AND EAST TONIGHT BRINGING SOME LIGHT FLURRIES TO THE NORTHERN
PLAINS. AREAS CLOSEST TO THE WYOMING BORDER WILL SEE A LITTLE
HIGHER AMOUNTS DUE TO SOME ENHANCED LIFT...HOWEVER AMOUNTS WILL BE
LIGHT WITH ACCUMULATIONS STAYING UNDER HALF AN INCH. TEMPERATURES
OVERNIGHT WILL BE COOL DUE TO THE COLD FRONT MOVING DOWN THIS
EVENING. LOWS FOR THE PLAINS WILL BE IN THE 20S AND SINGLE DIGITS
FOR THE MOUNTAINS.
FOR WEDNESDAY...THERE WILL BE A SLIGHT LULL IN THE SNOW INTENSITY
EARLY WEDNESDAY MORNING PRIOR TO THE NEXT UPPER LEVEL DISTURBANCE.
MODELS STILL SHOWING NEXT SHORTWAVE MOVING DOWN INTO COLORADO BY
THE AFTERNOON. THE JET WILL BE JUST TO THE SOUTH OF THE CWA BUT
LAPSE RATES ARE IMPRESSIVE AT 8-9 C/KM SO PERIODS OF CONVECTIVE
SNOW IS POSSIBLE WITH 1 INCH PER HOUR RATES DURING THE AFTERNOON
AT HIGHER ELEVATIONS. WITH THE NEXT WAVE UPPER LEVEL FLOW WILL
MOVE NW WHICH IS FAVORABLE FOR WEST FACING SLOPES. HIGHER SNOWFALL
AMOUNTS WILL BE POSSIBLE IN THESE AREAS. WILL KEEP THE WINTER
STORM WARNING FOR THE MOUNTAINS GOING UNTIL 6 PM DUE TO THE
CONVECTIVE NATURE AND THREAT OF BLOWING SNOW WITH THIS STORM.
FOR THE PLAINS THE FRONT WILL BRING A SLIGHT CHANCE OF SNOW BY THE
AFTERNOON AND EVENING WITH LIGHT ACCUMULATION EXPECTED. GFS IS
HINTING AT SOME QG MOVING OVER THE PLAINS IN THE AFTERNOON THAT
COULD BRING A SHORT PERIOD OF MORE INTENSE SNOWFALL THAT COULD
DROP A QUICK HALF INCH. SNOW WILL DECREASE IN THE EVENING WITH
SUBSIDENCE BEHIND THE FRONT. TEMPERATURES FOR WEDNESDAY WILL BE
SLIGHTLY COOLER IN THE UPPER 30S AND TEENS IN THE MOUNTAINS.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 142 PM MST TUE DEC 22 2015
ON WEDNESDAY NIGHT...A BROAD TROUGH OF LOW PRESSURE COVERS MUCH OF
THE WESTERN AND CENTRAL UNITED STATES...WITH A MOIST WESTERLY FLOW
ALOFT OVER COLORADO. IN ADDITION...A STRONG UPPER LEVEL JET STREAM
WILL BE ALONG THE NEW MEXICO BORDER...WITH AN UPPER LEVEL
DISTURBANCE MOVING ACROSS EASTERN COLORADO. THIS PATTERN SHOULD
PRODUCE SNOW AND BREEZY CONDITIONS ACROSS THE HIGH COUNTRY...WITH
THE POSSIBILITY FOR A FEW SNOW SHOWERS ACROSS THE PLAINS. THE SNOW
SHOULD DECREASE AFTER MIDNIGHT AS THE UPPER LEVEL DISTURBANCE MOVES
EAST OF COLORADO.
ON THURSDAY...THE UPPER TROUGH DEEPENS OVER THE WESTERN U.S. WITH
THE FLOW ALOFT OVER COLORADO BECOMING MORE SOUTHWESTERLY. THIS FLOW
IS NOT AS FAVORABLE FOR SNOW IN THE MOUNTAINS...HOWEVER THERE WILL
BE ENOUGH MOISTURE AVAILABLE TO PRODUCE SCATTERED SNOW SHOWERS
ACROSS THE HIGH COUNTRY.
ON CHRISTMAS DAY...THE UPPER TROUGH MOVES INTO COLORADO FROM THE
WEST...WITH QUITE A BIT OF QG LIFT MOVING ACROSS NORTH CENTRAL
AND NORTHEASTERN COLORADO. THIS QG-LIFT COMBINED WITH PLENTY OF
MOISTURE AND OROGRAPHIC LIFT SHOULD PRODUCE SNOW ACROSS THE
MOUNTAINS...HOWEVER THE SOUTHWEST FLOW ALOFT SHOULD LIMIT SNOWFALL
AMOUNTS. ONE THING TO NOTE IS THAT MODELS ARE SHOWING A 120KT JET
OVER CENTRAL COLORADO WHICH COULD ENHANCE SNOWFALL AMOUNTS SOUTH
OF INTERSTATE 70. FOR THE PLAINS...THE SOUTHWEST FLOW ALOFT IS NOT
FAVORABLE FOR SNOWFALL...HOWEVER...THERE SHOULD BE QUITE A BIT OF
QG- LIFT AROUND WHICH MAY BE ENOUGH TO PRODUCE SCATTERED LIGHT
SNOW SHOWERS.
MODELS ARE SHOWING A COLD FRONT MOVING INTO NORTHEASTERN COLORADO
FRIDAY NIGHT. NORTHERLY WINDS BEHIND THE FRONT...COMBINED WITH WEAK
QG LIFT MAY PRODUCE SOME LIGHT SNOW EAST OF THE MOUNTAINS ON
SATURDAY...MAINLY ALONG THE FRONT RANGE FOOTHILLS AND PALMER DIVIDE.
LOOKS LIKE THIS SYSTEM WONT BE MUCH OF AN IMPACT ACROSS OUR CWA DUE
TO THE FACT THAT THE MAIN UPPER LOW TRACKS ACROSS FAR SOUTHERN NEW
MEXICO AND INTO OKLAHOMA. THE MODELS ARE HINTING THE POSSIBILITY OF
SOME LIGHT SNOWFALL ACROSS OUR FAR EASTERN ZONES EARLY NEXT ON THE
BACK SIDE OF THIS STORM SYSTEM...THEREFORE WILL KEEP SOME LOW POPS
IN THESE AREAS.
TEMPERATURES ARE EXPECTED TO REMAIN MUCH BELOW NORMAL THROUGH THE
PERIOD. SATURDAY LOOKS TO BE THE COLDEST DAY...WITH DAYTIME HIGHS
POSSIBLY NOT MAKING IT OUT OF THE TEENS ON THE PLAINS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1249 AM MST WED DEC 23 2015
WITH CLEARING SKIES BEHIND THE EARLIER SNOWBAND...AREAS OF FOG ARE
BEGINNING TO FORM. HIRES MODELS ARE KEEPING STRONG ENOUGH
DOWNSLOPE WINDS IN FOR THE FOG TO STAY NORTH OR KDEN AND
KAPA...SHOULD MAINLY IMPACT KBJC AND NORTH. THOUGH CAN`T RULE OUT
FOG INTO THE OTHER AIRPORTS. HIRES MODELS ALSO BEING PERSISTENT
ABOUT ANOTHER BATCH OF SNOW SHOWERS PUSHING THROUGH BETWEEN
11-14Z...MAINLY METRO AREAS AND SOUTH. HAVE ADJUSTED TAFS FOR
THIS. NOT EXPECTING MUCH ACCUMULATION AS BEST DYNAMICS HAVE PUSHED
EAST. SKIES WILL THEN CLEAR AGAIN THROUGH WEDNESDAY MORNING AS
DOWNSLOPING WILL DEVELOP. DRAINAGE WINDS WILL VEER TO THE
NORTHWEST IN THE AFTERNOON. SLIGHT CHANCE TO SEE SOME SNOW SHOWERS
AGAIN...BUT NOT UNTIL LATE AFTERNOON OR EVENING. QUICK MVFR
CONDITIONS POSSIBLE WITH THESE SHOWERS.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL 6 PM MST THIS EVENING FOR COZ031-033-
034.
&&
$$
UPDATE...KRIEDERMAN
SHORT TERM...BOWEN
LONG TERM...KALINA
AVIATION...KRIEDERMAN
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1024 PM MST TUE DEC 22 2015
.UPDATE...
ISSUED AT 1010 PM MST TUE DEC 22 2015
RAPID ZONAL FLOW ALOFT EQUATES TO RAPID CHANGES IN OUR WEATHER
CONDITIONS THIS EVENING. BANDED SNOWFALL HANGING OVER NORTHERN
PORTIONS OF THE CWA ALL EVENING HAS MADE LITTLE SOUTHWARD PROGRESS
AS MESOSCALE MODELS INDICATED. ALTHOUGH IN THE PAST HOUR THE TAIL
END OF THIS SNOW BAND OVERT THE FRONT RANGE HAS SHOWN SIGNS OF
ADVANCING SOUTHWARD IN RESPONSE TO THE NEXT INFLUX OF PACIFIC
MOISTURE SPREADING INTO THE NORTH CENTRAL MTNS AT THIS HOUR.
SNOWFALL RATES UNDER THE SNOW BAND NORTH OF DENVER IN THE 0.5 TO 1
INCH PER HOUR RATE. SHOULD SEE SIMILAR SNOWFALL RATES DEVELOPING
THE HIGH COUNTRY OVER THE NEXT HOUR OR TWO...WITH POSSIBLY GREATER
RATES OVER THE HIGH TERRAIN IN SUMMIT AND WESTERN PARK COUNTIES.
HRRR AND RAP INDICATE THE HIGHEST 6-HR SNOW TOTALS ON THE PLAINS
ACROSS MORGAN...WASHINGTON AND LOGAN COUNTIES WHERE 1-3 INCH
AMOUNTS ARE POSSIBLE. CLOSER TO THE FRONT RANGE COULD ANOTHER
INCH OR TWO FROM DENVER NORTHWARD AND PERHAPS AND INCH OR SO IN
THE DENVER AREA BEFORE 10Z TONIGHT...THAT`S ASSUMING A SNOW BAND
FORMS FARTHER SOUTH AS THE HRRR AND RAP INDICATE. SHOULD SEE LIGHT
TO MODERATE SNOWFALL REST OF TONIGHT IN THE HIGH COUNTRY WHERE WE
COULD SEE ANOTHER 3-5 INCHES ON WEST FACING SLOPES BY MORNING.
UPDATED FORECAST WITH THESE CHANGES ALREADY OUT.
UPDATE ISSUED AT 748 PM MST TUE DEC 22 2015
SNOW OVER LARIMER AND WELD COUNTIES WILL TO SPREAD SOUTH AND EAST
THROUGH THE EVENING AND OVERNIGHT HOURS. THE 00Z SOUNDING SHOWED A
NEARLY DRY ADIABATIC LAPSE RATE FROM 750MB UP TO 300 MB...SO
HEAVY CONVECTIVE SNOW WILL REMAIN POSSIBLE WITH BRIEF SNOWFALL
RATES OF 1 TO 2 INCHES PER HOUR POSSIBLE. AN ESTIMATED HALF INCH
HAS FALLEN IN FORT COLLINS SO FAR BASED ON WEB CAMERAS. INCREASED
POPS AND SNOWFALL AMOUNTS EARLIER AND THEY STILL APPEAR ON TRACK.
UPDATE ISSUED AT 518 PM MST TUE DEC 22 2015
LATEST SHORT RANGE MODELS AND 18Z MODELS SHOWING MORE SNOW FOR
NORTHEAST COLORADO TONIGHT. FAVORABLE SIDE OF THE JET WILL BE OVER
THE AREA. IN ADDITION...AIRMASS WILL BE UNSTABLE WITH LAPSE RATES
OF 6 TO 8.5 C/KM. LATEST RADAR SHOWING INCREASING RETURNS...MOST
OF WHICH IS VIRGA OVER LARIMER AND WELD COUNTIES. AIRMASS WILL
CONTINUE TO MOISTEN AND EXPECT SNOW TO INCREASE THROUGH THE
EVENING HOURS. UPDATED TO INCREASE POPS INTO THE LIKELY RANGE.
MOST AREAS WILL SEE LIGHT SNOWFALL...AN INCH OR LESS. HOWEVER A
FEW SNOW BANDS WILL BE POSSIBLE WHERE UP TO 3 INCHES MAY FALL.
TEMPERATURES WILL BE IN THE UPPER 20S TO LOWER 30S. SO ROADS WILL
BE SLOW TO ICE UP EXCEPT UNDER THE HEAVIER SNOW BANDS. THIS
SYSTEM WILL BE QUICK MOVING AND BE OUT OF THE AREA BY SUNRISE.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 142 PM MST TUE DEC 22 2015
A BROAD UPPER LEVEL TROUGH CONTINUES TO BRING INCREASED MOISTURE
AND STRONG WNW WINDS INTO THE MOUNTAINS. SNOW SHOWERS AND GUSTY
WINDS WILL CONTINUE OVER THE MOUNTAINS THROUGH THE EVENING HOURS
BEFORE DIMINISHING OVERNIGHT. TOTAL ACCUMULATIONS WILL BE 8 TO 18
INCHES WITH THE HIGHER AMOUNTS OVER THE NORTHERN MOUNTAINS ON WEST
FACING SLOPES. AREAS NEAR THE PARK AND GORE RANGES IN THE NE
PORTIONS OF THE CWA COULD SEE UP TO 2 FEET ON WEST FACING SLOPES
THROUGH TOMORROW AFTERNOON. ON THE PLAINS THE SURFACE LOW THAT HAS
BEEN KEEPING SNOW OUT OF THE PICTURE WILL MOVE OFF TO THE SOUTH
AND EAST TONIGHT BRINGING SOME LIGHT FLURRIES TO THE NORTHERN
PLAINS. AREAS CLOSEST TO THE WYOMING BORDER WILL SEE A LITTLE
HIGHER AMOUNTS DUE TO SOME ENHANCED LIFT...HOWEVER AMOUNTS WILL BE
LIGHT WITH ACCUMULATIONS STAYING UNDER HALF AN INCH. TEMPERATURES
OVERNIGHT WILL BE COOL DUE TO THE COLD FRONT MOVING DOWN THIS
EVENING. LOWS FOR THE PLAINS WILL BE IN THE 20S AND SINGLE DIGITS
FOR THE MOUNTAINS.
FOR WEDNESDAY...THERE WILL BE A SLIGHT LULL IN THE SNOW INTENSITY
EARLY WEDNESDAY MORNING PRIOR TO THE NEXT UPPER LEVEL DISTURBANCE.
MODELS STILL SHOWING NEXT SHORTWAVE MOVING DOWN INTO COLORADO BY
THE AFTERNOON. THE JET WILL BE JUST TO THE SOUTH OF THE CWA BUT
LAPSE RATES ARE IMPRESSIVE AT 8-9 C/KM SO PERIODS OF CONVECTIVE
SNOW IS POSSIBLE WITH 1 INCH PER HOUR RATES DURING THE AFTERNOON
AT HIGHER ELEVATIONS. WITH THE NEXT WAVE UPPER LEVEL FLOW WILL
MOVE NW WHICH IS FAVORABLE FOR WEST FACING SLOPES. HIGHER SNOWFALL
AMOUNTS WILL BE POSSIBLE IN THESE AREAS. WILL KEEP THE WINTER
STORM WARNING FOR THE MOUNTAINS GOING UNTIL 6 PM DUE TO THE
CONVECTIVE NATURE AND THREAT OF BLOWING SNOW WITH THIS STORM.
FOR THE PLAINS THE FRONT WILL BRING A SLIGHT CHANCE OF SNOW BY THE
AFTERNOON AND EVENING WITH LIGHT ACCUMULATION EXPECTED. GFS IS
HINTING AT SOME QG MOVING OVER THE PLAINS IN THE AFTERNOON THAT
COULD BRING A SHORT PERIOD OF MORE INTENSE SNOWFALL THAT COULD
DROP A QUICK HALF INCH. SNOW WILL DECREASE IN THE EVENING WITH
SUBSIDENCE BEHIND THE FRONT. TEMPERATURES FOR WEDNESDAY WILL BE
SLIGHTLY COOLER IN THE UPPER 30S AND TEENS IN THE MOUNTAINS.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 142 PM MST TUE DEC 22 2015
ON WEDNESDAY NIGHT...A BROAD TROUGH OF LOW PRESSURE COVERS MUCH OF
THE WESTERN AND CENTRAL UNITED STATES...WITH A MOIST WESTERLY FLOW
ALOFT OVER COLORADO. IN ADDITION...A STRONG UPPER LEVEL JET STREAM
WILL BE ALONG THE NEW MEXICO BORDER...WITH AN UPPER LEVEL
DISTURBANCE MOVING ACROSS EASTERN COLORADO. THIS PATTERN SHOULD
PRODUCE SNOW AND BREEZY CONDITIONS ACROSS THE HIGH COUNTRY...WITH
THE POSSIBILITY FOR A FEW SNOW SHOWERS ACROSS THE PLAINS. THE SNOW
SHOULD DECREASE AFTER MIDNIGHT AS THE UPPER LEVEL DISTURBANCE MOVES
EAST OF COLORADO.
ON THURSDAY...THE UPPER TROUGH DEEPENS OVER THE WESTERN U.S. WITH
THE FLOW ALOFT OVER COLORADO BECOMING MORE SOUTHWESTERLY. THIS FLOW
IS NOT AS FAVORABLE FOR SNOW IN THE MOUNTAINS...HOWEVER THERE WILL
BE ENOUGH MOISTURE AVAILABLE TO PRODUCE SCATTERED SNOW SHOWERS
ACROSS THE HIGH COUNTRY.
ON CHRISTMAS DAY...THE UPPER TROUGH MOVES INTO COLORADO FROM THE
WEST...WITH QUITE A BIT OF QG LIFT MOVING ACROSS NORTH CENTRAL
AND NORTHEASTERN COLORADO. THIS QG-LIFT COMBINED WITH PLENTY OF
MOISTURE AND OROGRAPHIC LIFT SHOULD PRODUCE SNOW ACROSS THE
MOUNTAINS...HOWEVER THE SOUTHWEST FLOW ALOFT SHOULD LIMIT SNOWFALL
AMOUNTS. ONE THING TO NOTE IS THAT MODELS ARE SHOWING A 120KT JET
OVER CENTRAL COLORADO WHICH COULD ENHANCE SNOWFALL AMOUNTS SOUTH
OF INTERSTATE 70. FOR THE PLAINS...THE SOUTHWEST FLOW ALOFT IS NOT
FAVORABLE FOR SNOWFALL...HOWEVER...THERE SHOULD BE QUITE A BIT OF
QG- LIFT AROUND WHICH MAY BE ENOUGH TO PRODUCE SCATTERED LIGHT
SNOW SHOWERS.
MODELS ARE SHOWING A COLD FRONT MOVING INTO NORTHEASTERN COLORADO
FRIDAY NIGHT. NORTHERLY WINDS BEHIND THE FRONT...COMBINED WITH WEAK
QG LIFT MAY PRODUCE SOME LIGHT SNOW EAST OF THE MOUNTAINS ON
SATURDAY...MAINLY ALONG THE FRONT RANGE FOOTHILLS AND PALMER DIVIDE.
LOOKS LIKE THIS SYSTEM WONT BE MUCH OF AN IMPACT ACROSS OUR CWA DUE
TO THE FACT THAT THE MAIN UPPER LOW TRACKS ACROSS FAR SOUTHERN NEW
MEXICO AND INTO OKLAHOMA. THE MODELS ARE HINTING THE POSSIBILITY OF
SOME LIGHT SNOWFALL ACROSS OUR FAR EASTERN ZONES EARLY NEXT ON THE
BACK SIDE OF THIS STORM SYSTEM...THEREFORE WILL KEEP SOME LOW POPS
IN THESE AREAS.
TEMPERATURES ARE EXPECTED TO REMAIN MUCH BELOW NORMAL THROUGH THE
PERIOD. SATURDAY LOOKS TO BE THE COLDEST DAY...WITH DAYTIME HIGHS
POSSIBLY NOT MAKING IT OUT OF THE TEENS ON THE PLAINS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1010 PM MST TUE DEC 22 2015
SNOW CHANCES WILL INCREASE AT KBJC AND KDEN WITHIN THE HOUR WITH A
BAND OF LIGHT TO MODERATE SNOWFALL SWINGING OFF THE FRONT RANGE
AND ACROSS NORTHERN PORTIONS OF THE METRO AREA. CEILINGS HAVE
QUICKLY LOWERED IN THE PAST 30 MINS IN RESPONSE TO THE APPROACHING
SNOW BAND. COULD SEE A HALF INCH OF SNOW AT BOTH AIRPORTS BY THE
TIME THE BAND PASSES BY. COULD THEN SEE ANOTHER BAND OR TWO OF
SNOW PASS OVER THE METRO AREA LATER TONIGHT POSSIBLY DEPOSITING
ANOTHER 0.5 TO 1 INCH OF SNOW IN THE METRO AREA AND AT KDEN. ILS
CIGS AND VSBYS LIKELY WITH THESE PASSING SNOW BANDS. WINDS WILL
ALSO BE VARIABLE IN DIRECTION AT UNDER 12KTS WITH THESE SHOWERS.
AFTER 10Z WITH PARTIAL CLEARING SKIES COULD SEE PATCHY DENSE FOG
FORMING ACROSS NORTHERN PORTIONS OF THE METRO AREA. THAT INCLUDES
KDEN AND KBJC. COULD SEE VSBYS LOWERING TO 1.5-3 MILES IN THE FOG.
OTHERWISE S-SELY WINDS OF 5-8KTS WILL PREVAIL IN THE DENVER AREA
FOR THE REMAINDER OF THE NIGHT.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL 6 PM MST WEDNESDAY FOR COZ031-033-034.
&&
$$
UPDATE...BAKER
SHORT TERM...BOWEN
LONG TERM...KALINA
AVIATION...BAKER
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
412 AM EST WED DEC 23 2015
.SYNOPSIS...
A WARM AND MOIST SOUTH FLOW WILL DOMINATE THROUGH MUCH OF THE WEEK
ASSOCIATED WITH OFFSHORE HIGH PRESSURE. NUMEROUS SHOWERS WILL
OCCUR TODAY AND TONIGHT WITH SOME DECREASE IN COVERAGE THURSDAY AS
UPPER RIDGING BECOMES A BIT MORE ESTABLISHED. VERY HEAVY RAIN MAY
OCCUR WITH SOME OF THE SHOWERS TODAY AND TONIGHT. MUCH ABOVE
NORMAL TEMPERATURES WILL CONTINUE.
&&
.NEAR TERM /THROUGH TONIGHT/...
HIGH LOW-LEVEL MOISTURE HAS RESULTED IN DENSE FOG OVER MUCH OF THE
FORECAST AREA. THE GFS LAMP MAINTAINS SIGNIFICANT FOG THROUGH
MUCH OF THE MORNING. WE HAVE POSTED A DENSE FOG ADVISORY.
MOISTURE WILL REMAIN VERY HIGH THROUGH TONIGHT ASSOCIATED
WITH THE SOUTHERLY FLOW FROM OFF THE ATLANTIC AND GULF PLUS
SOUTHWEST MID- LEVEL FLOW ORIGINATING FROM THE TROPICAL PACIFIC.
THE MODELS AND OBSERVATION TRENDS INDICATE PRECIPITABLE WATER NEAR
1.9 OF AN INCH. THE NAM AND GFS INDICATE THE H85 FLOW INCREASING
TODAY WITH SPEEDS THIS AFTERNOON AND TONIGHT OF 40 TO 50 KNOTS.
THE STRONG JET AND HIGH MOISTURE INDICATE POSSIBLE EXCESSIVE RAIN
AND A FLASH FLOOD WATCH HAS BEEN POSTED. THE HIGH-RESOLUTION
MODELS HAVE NOT BEEN CONSISTENT WITH THE TIMING OF GREATEST SHOWER
COVERAGE. THE 07Z HRRR DISPLAYED SCATTERED COVERAGE WITH SOME
INCREASE DURING THE AFTERNOON. RADAR TRENDS SUPPORT NUMEROUS
SHOWERS IN THE NEAR TERM. USED THE WPC GUIDANCE FOR THE GENERAL
RAINFALL FORECAST. THE STRONG SHEAR INDICATES A POSSIBILITY OF
SEVERE THUNDERSTORMS BUT THE THREAT APPEARS LIMITED BY A LACK OF
SIGNIFICANT SURFACE- BASED INSTABILITY BECAUSE OF CLOUD COVER AND
NUMEROUS SHOWERS. THE GFS LAMP AND NAM BUFKIT MOMENTUM TRANSFER
TOOL INDICATE WIND GUSTS OF 18 TO 25 KNOTS THIS AFTERNOON. LEANED
TOWARD THE LOWER VALUES BECAUSE OF EXPECTED CLOUDINESS AND LIMITED
MIXING. USED THE GUIDANCE CONSENSUS FOR THE TEMPERATURE FORECAST.
&&
.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
SURFACE HIGH PRESSURE OFF THE COAST WILL CONTINUE TO CIRCULATE A
MOIST SOUTH FLOW INTO THE FORECAST AREA THROUGH THURSDAY NIGHT
SUPPORTING SHOWERS. HOWEVER...THE MODELS HAVE BEEN CONSISTENT
INDICATING UPPER HEIGHTS BUILDING OVER THE FORECAST AREA FROM THE
SOUTHEAST. THE DIMINISHING UPPER SUPPORT SHOULD HELP DECREASE
SHOWER COVERAGE. THE NAM...GFS...AND ECMWF MOS INDICATE CHANCE
POPS. THE BUILDING UPPER RIDGE AND SOUTH FLOW WILL BRING MUCH
ABOVE NORMAL TEMPERATURES AND RECORDS FOR THE DATE MAY OCCUR. USED
THE GUIDANCE CONSENSUS FOR THE HIGH TEMPERATURE FORECAST WITH
EXPECTED LINGERING CLOUDINESS LIMITING HIGH TEMPERATURES. HIGH
LOW-LEVEL MOISTURE SHOULD RESULT IN WIDESPREAD STRATUS AND FOG
DURING THE EARLY MORNING HOURS.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
THE GFS AND ECMWF INDICATE UPPER RIDGING ESTABLISHED OVER THE
FORECAST AREA FRIDAY THROUGH SUNDAY. HOWEVER...THE WARM AND MOIST
SOUTH FLOW ASSOCIATED WITH OFFSHORE SURFACE HIGH PRESSURE SUPPORTS
POSSIBLE SHOWERS. THE GFS AND ECMWF MOS HAVE POPS OF 20 TO 30
PERCENT. THE MOS MAINTAINS MUCH ABOVE NORMAL TEMPERATURES.
THE MODELS INDICATE A WEAKENED UPPER RIDGE MONDAY AND TUESDAY. THE
MODELS HAVE NOT BEEN CONSISTENT WITH THE POSITION OF A FRONTAL
SYSTEM BUT DO GENERALLY INDICATE INCREASED MOISTURE. THE GFS AND
ECMWF MOS HAVE POPS OF 20 TO 50 PERCENT WITH CONTINUED ABOVE
NORMAL TEMPERATURES.
&&
.AVIATION /08Z WEDNESDAY THROUGH SUNDAY/...
WIDESPREAD PROLONGED LIFR CONDITIONS EXPECTED EARLY THIS
MORNING...WITH CONDITIONS AT OR BELOW AIRPORT MINIMUMS POSSIBLE.
IFR/LIFR CONDITIONS ACROSS THE AREA EARLY THIS MORNING...WITH THE
EXCEPTION OF OGB WITH MVFR. LATEST RADAR MOSAIC INDICATING MAINLY
LIGHT RAIN ACROSS THE AREA. OVERALL DO NOT EXPECT MUCH IN THE WAY OF
IMPROVEMENT BEFORE SUNRISE. LATEST HRRR INDICATING THE BEST CHANCE
FOR THE HEAVIEST PRECIPITATION MOVING BACK INTO THE AREA WILL BE
LATE MORNING INTO THE AFTERNOON. HOWEVER...CONSIDERABLE
UNCERTAINTIES REMAIN WITH REGARDS TO PLACEMENT...TIMING...AND
INTENSITY. UNCERTAINTIES ALSO REMAIN HOW MUCH CIGS/VSBYS WILL
IMPROVE LATER TODAY. MODEL GUIDANCE HINTING THAT CONDITIONS MAY
IMPROVE TO MVFR LATER THIS AFTERNOON. FOR NOW WILL LEAN TOWARDS HIGH-
END IFR/MVFR THIS AFTERNOON.
EXTENDED AVIATION OUTLOOK...CHANCE OF RAIN...AND MAINLY LATE NIGHT
AND MORNING RESTRICTIONS...WEDNESDAY NIGHT THROUGH MONDAY.
&&
.HYDROLOGY...
RIVER FLOOD WARNINGS HAVE BEEN POSTED FOR SOME OF THE RIVER
FORECAST POINTS. FLASH FLOOD WARNINGS MAY BE REQUIRED AT TIMES
THROUGH TONIGHT...MAINLY FOR SMALL STREAMS AND URBAN LOCATIONS.
&&
.CLIMATE...
HIGH TEMPERATURE RECORDS FOR CHRISTMAS EVE AND CHRISTMAS DAY.
COLUMBIA METRO AIRPORT (CAE)
DEC 24...76 SET IN 1964. FORECASTING 80.
DEC 25...79 SET IN 1955. FORECASTING 81.
AUGUSTA BUSH FIELD (AGS)
DEC 24...80 SET IN 1964. FORECASTING 80.
DEC 25...79 SET IN 1984. FORECASTING 81.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...DENSE FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR GAZ040-
063>065-077.
FLASH FLOOD WATCH THROUGH THURSDAY AFTERNOON FOR GAZ040-
063>065.
SC...DENSE FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR SCZ015-016-
018-020>022-025>031-035>038-041.
FLASH FLOOD WATCH THROUGH THURSDAY AFTERNOON FOR SCZ015-016-
018-020>022-025>028-030.
&&
$$
SYNOPSIS...99
NEAR TERM...99
SHORT TERM...99
LONG TERM...99
AVIATION...99
HYDROLOGY...
CLIMATE...
AREA FORECAST DISCUSSION
National Weather Service Lincoln IL
330 AM CST WED DEC 23 2015
.SHORT TERM...(Today)
ISSUED AT 330 AM CST WED DEC 23 2015
09z/3am surface analysis shows a 986mb low over south-central Kansas
with a warm front extending eastward across Missouri into southern
Illinois. Southerly flow to the south of the front has resulted in
temperatures steadily rising into the lower 60s across Kentucky and
far southern Illinois...and well into the 50s further north across
the KILX CWA. Due to low-level warm/moist advection, widespread fog
has developed along/east of a Bloomington to Taylorville line. Do
not think dense fog will be an issue however, as surface winds have
been strong enough to provide enough mixing of the atmosphere to
keep visbys around 1 mile at the lowest. HRRR shows the fog
persisting through early morning before gradually dissipating and
pushing further north.
Current water vapor imagery shows vigorous short-wave trough
tracking across the Oklahoma/Texas panhandles, and this feature is
already triggering widespread convection across eastern Oklahoma
into Arkansas. 4km WRF-NMM has a very good handle on the convection
and shows it tracking northeastward into central Illinois after
13/14z. Based on this forecast and current radar trends, have gone
with categorical PoPs for showers/thunder this morning. This
initial surge of convection will lift into northern Illinois toward
midday, resulting in a lull in the precip across the KILX CWA by
early afternoon. May even see a few breaks in the overcast as per
the HRRR cloud height forecast. Big question then becomes how much
convection will develop along an advancing cold front late this
afternoon into the evening. Several models suggest much of central
Illinois may only see scattered thunderstorms, with the more
concentrated area of convection further south from the I-70 corridor
southward into the Tennessee River Valley. Given robust instability
characterized by SBCAPEs of 500-1000J/kg and strong 0-6km bulk shear
of 70-80kt, have continued with categorical PoPs along/ahead of the
front this afternoon. Have also mentioned severe, as latest Day 1
outlook from SPC now places the entire area under a Slight Risk.
Aside from the storm chances, this will be a windy and extremely
warm day. Southerly winds will gust to between 35 and 40 mph,
helping push temperatures to near record levels in the middle to
upper 60s. In fact, if a few breaks do indeed develop in the
overcast, would not be surprised to see temps rise into the lower
70s in a few spots.
&&
.LONG TERM...(Tonight through Tuesday)
ISSUED AT 330 AM CST WED DEC 23 2015
As deep low pressure tracks from eastern Iowa this evening to Lake
Superior by midnight, impressive pressure rises will create very
strong southwesterly winds across the area this evening behind the
departing cold front. A Wind Advisory may need to be issued for
areas north of the I-70 corridor, as gusts could exceed 40 mph. Will
hold off on the advisory for now, waiting until the strong to
potentially severe convection clears the area later today.
Showers/storms will quickly exit into Indiana by midnight, with dry
weather expected overnight.
A lull in the action is still anticipated for Thursday into Friday,
with slightly cooler high temperatures in the 40s and 50s. After
that, a wet/unsettled weekend is on tap. 00z Dec 23 models are in
relatively good agreement concerning the heavy rain set-up
initially, with both the GFS and ECMWF showing widespread showers
and even a few thunderstorms for Saturday/Saturday night. Latest
GFS is beginning to look more like previous runs of the ECMWF, which
shows a northern stream short-wave pushing the main baroclinic zone
southward into the Ohio River Valley on Sunday. In fact, the latest
ECMWF now shows the front south of the Ohio River and features dry
weather across central Illinois Sunday afternoon and night. Am not
ready to go quite that far yet, although the southward trend is
definitely there. Have therefore lowered PoPs substantially across
the northern half of the CWA Sunday/Sunday night and have pushed
thunder mention further south out of the area. Closed upper low
over the Desert Southwest will eventually eject northeastward,
bringing higher PoPs back by Monday/Monday night. Rain chances will
then finally decrease by Tuesday as the low lifts into the Great
Lakes.
&&
.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
ISSUED AT 1055 PM CST TUE DEC 22 2015
IFR to LIFR conditions are expected to continue into the early
afternoon hours of Wednesday as a strong storm system passes
across the area Wednesday evening. Widespread stratus clouds
and areas of fog have expanded north into the forecast area
this evening and expect that to hold tonight as southerly
winds draw an increasing amount of low level moisture northward
into our area ahead of the storm. Rain will spread northeast into
central Illinois after midnight and encompass most of our area
during the morning and early afternoon hours before a warm front
shifts north out of our area by late afternoon. Once that occurs,
we may see a temporary improvement in cigs and vsbys with the
rain coming to a temporary end. A cold front will then surge
east across the area Wed evening in the 23z-03z time frame with
scattered TSRA possible along the front. Strong gradient winds
are expected to develop over the area later Wednesday morning
and continue into the evening hours before shifting into the
southwest and west after 22z at SPI and PIA, and by 03z in
CMI.
&&
.ILX Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...Barnes
LONG TERM...Barnes
AVIATION...Smith
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
327 PM EST TUE DEC 22 2015
.UPDATE...
THE LONG TERM AND AVIATION SECTIONS HAVE BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 256 PM EST TUE DEC 22 2015
PATTERN TO REMAIN MILD THROUGH AND BEYOND THE SEVEN DAY FORECAST.
A COUPLE OF SIGNIFICANT STORMS SYSTEMS...WEDNESDAY WITH POTENTIAL
DAMAGING WIND...AND THIS WEEKEND...WITH HEAVY RAIN THAT MAY LEAD
TO FLOODING...WILL FINISH OUT THE ACTIVE WEATHER PATTERN LATE THIS
YEAR.
&&
.NEAR TERM /REST OF TONIGHT/...
ISSUED AT 1002 PM EST TUE DEC 22 2015
AFTER SOME SUNSHINE FOR MOST LATE THIS AFTERNOON...LOWER STRATUS
HAS ADVECTED BACK ACROSS MOST OF THE FORECAST AREA AS OF 03Z WITH
MOISTURE STREAMING NORTH AND INTERACTING WITH THE SHALLOW
INVERSION STILL PRESENT. FAR NORTHERN COUNTIES HAVE MANAGED TO
DROP QUICKLY INTO THE MID AND UPPER 30S THIS EVENING WHERE SKIES
HAVE REMAINED CLEAR THE LONGEST...WITH TEMPS RANGING FROM THE MID
40S TO LOWER 50S OVER MOST OF THE REST OF THE FORECAST AREA.
PIECES ALREADY STARTING TO ALIGN THAT WILL BRING THE WARM
TEMPERATURES WEDNESDAY ALONG WITH THE UNUSUAL SEVERE WEATHER RISK
FOR THE AFTERNOON AND EVENING WEDNESDAY. POLEWARD MOISTURE RETURN
OVER THE LAST 6 HOURS FROM THE GULF COAST HAS BEEN IMPRESSIVE TO
OUR SOUTH TO PUT IT MILDLY. 60+ DEGREE DEWPOINTS NOW WELL INTO THE
TENNESSEE VALLEY AND WILL LIKELY ADVANCE INTO KENTUCKY AFTER
MIDNIGHT. ALREADY SEEING PATCHY FOG IN THE LOWER WABASH VALLEY AS
THE DEEPER MOISTURE ARRIVES AND EXPECT THAT TO CONTINUE OVERNIGHT
IN SOME AREAS.
LOWS HAVE ALREADY BEEN MET...WITH TEMPERATURES STEADILY
CLIMBING FOR THE REST OF THE NIGHT AS WARM MOIST AIR SPREADS
NORTH. RAP AND NAM BOTH HINTING AT SURFACE TEMPS NEAR 60 OVER
SOUTHERN FORECAST AREA BY DAYBREAK AND CONSIDERING CURRENT TEMPS
OVER THE TENNESSEE AND LOWER MISSISSIPPI VALLEYS...THAT DOES NOT
SEEM FAR OFF.
CONVECTION ACROSS THE LOWER MISSISSIPPI VALLEY WILL RACE NORTHEAST
OVERNIGHT AND WHILE BULK OF THE ACTIVITY SHOULD REMAIN TO THE
SOUTHEAST OF THE FORECAST AREA...HI-RES GUIDANCE CONTINUING TO
CAPTURE SCATTERED SHOWERS INCREASING IN COVERAGE AFTER 06Z FROM
THE SOUTH AS WARM ADVECTION INTENSIFIES OVER THE OHIO VALLEY.
HAVE ADJUSTED POPS SLIGHTLY...BUT INTRODUCING LOW CHANCES FOR
ENTIRE FORECAST AREA FOR THE PREDAWN HOURS. MEANWHILE BACK TO THE
SOUTHWEST...EXPECT RAPID CONVECTIVE DEVELOPMENT OVER THE OZARKS AS
THE INTENSE LOW PRESSURE SWINGS OUT THROUGH THE CENTRAL PLAINS AND
BEGINS TO INTERACT WITH THE GULF MOISTURE FETCH. THIS WILL
CONTINUE TO INCREASE IN COVERAGE AND EXPAND INTO THE REGION BY MID
TO LATE MORNING WEDNESDAY.
ZONE AND GRID UPDATES OUT.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY/...
ISSUED AT 256 PM EST TUE DEC 22 2015
FORECAST ISSUE IS SEVERE WEATHER THREAT WEDNESDAY. THOUGH MODEL
DYNAMICS IN FAIRLY GOOD AGREEMENT...AMOUNT OF DESTABILIZATION
PRIOR TO MAIN SHOWER/SQUALL BAND ARRIVAL IN THE AFTERNOON MAY
DETERMINE HOW GUSTY CONVECTION MAY GET. MODEL SOUNDINGS SUGGEST
MIXING OF 40MPH GUSTS TO THE GROUND PRIOR TO ANY STORM LINE MAY
OCCUR AS WELL SO HAVE INCLUDED GUSTY WORDING IN THE FORECAST.
NAM SOMEWHAT DIFFERENT THAN OTHER MODELS IN HAVING QUITE DISTINCT
AND SIMILARLY POTENT ROUNDS OF STORMS...AFTERNOON AND THEN EVENING
WITH COLD FRONT TIED WITH TWO INSTABILITY AXES. WILL LEAN TOWARD
A BLEND OF MODELS AND FORECAST WORDING MAY NOT REFLECT THE
SEPARATION BUT TWO HEAVIER ROUNDS OF RAIN APPEAR POSSIBLE.
STRENGTH OF WARM ADVECTION SHOULD LEAD TO ADVERTISED RECORD OR
NEAR RECORD HIGHS IN THE UPPER 60S WEDNESDAY.
WEDNESDAY NIGHT...NAM IS SLOWEST WITH COLD FRONT WHILE GFS IS
QUITE FAST SO WILL AVERAGE BETWEEN THESE. END RESULT IS AT LEAST
ONE MORE DECENT SHOT OF RAIN WITH COLD FRONT PASSAGE DURING THE
EVENING WITH LINGERING SHOWERS ENDING BEFORE DAYBREAK.
THURSDAY AND PART OF FRIDAY...A DRY TRANQUIL PERIOD IS IN STORE
AS HIGH PRESSURE BUILDS IN BEHIND THE INTENSIFYING LOW THAT LIFTS
NE INTO THE HUDSON BAY AREA. HAVE KEPT TEMPERATURES NEAR GUIDANCE
AND STILL WELL ABOVE NORMAL WITH HIGHS MAINLY IN THE 50S AND LOWS
ABOVE FREEZING.
AS THE NEXT STRONG SHORTWAVE DUMPS INTO THE WESTERN TROUGH...THE
SURFACE BOUNDARY THAT SLIPPED INTO KENTUCKY THURSDAY WILL LIFT
BACK NORTH TO BEGIN THE NEXT RAINY PERIOD.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
ISSUED AT 342 AM EST WED DEC 23 2015
MODELS CONTINUE TO ADVERTISE AN EXTREMELY STRONG BAROCLINIC ZONE IN
PLACE ACROSS THE REGION OVER THE WEEKEND AND INTO EARLY NEXT
WEEK...WITH POTENTIAL FOR SIGNIFICANT MOISTURE ADVECTION INTO THE
FRONTAL ZONE ON A PERSISTENT 40 TO 50 KT LOW LEVEL JET THROUGHOUT
THE WEEKEND. THIS WOULD SET THE STAGE FOR MULTIPLE ROUNDS OF
POTENTIALLY HEAVY RAINFALL. EVEN WITH MODEL TENDENCIES TO BE OVERLY
AGGRESSIVE WITH MOISTURE TRANSPORT...MODEL PRECIPITABLE WATER VALUES
WOULD BE EXTREMELY ANOMALOUSLY HIGH CLIMATOLOGICALLY SPEAKING...99TH
PERCENTILE OR GREATER...NEARING THE MAXIMUM EXPECTED VALUE FOR THE
TIME OF YEAR.
INSTABILITY INDICES SUGGEST AT LEAST A CHANCE OF THUNDER IS MERITED
ACROSS AT LEAST SOME PORTION OF CENTRAL INDIANA SATURDAY THROUGH
MONDAY.
MODEL BLENDED FORECASTS SHOW POTENTIAL FOR 3 TO 5 INCHES OF RAINFALL
DURING THE HOLIDAY WEEKEND...WITH AREAS OF 5 PLUS POSSIBLE. THIS
COULD BE HEAVILY IMPACTED BY THE POSITION OF THE FRONTAL ZONE...AND
SIGNIFICANT UNCERTAINTY REMAINS WITH REGARD TO THAT.
NONETHELESS...EVEN WITH THE AREA HAVING BEEN BELOW NORMAL ON
PRECIPITATION FOR THE LAST 5 MONTHS OR SO...THE DECREASED ACTIVITY
OF VEGETATION DURING THE COOL SEASON...ALONG WITH THE POTENTIAL
DURATION AND INTENSITY OF RAINFALL WILL PRESENT A POTENTIALLY
SIGNIFICANT FLOOD THREAT ACROSS THE REGION.
&&
.AVIATION /DISCUSSION FOR THE 23/09Z TAF UPDATE/...
ISSUED AT 342 AM EST WED DEC 23 2015
IFR CONDITIONS WORSENING ACROSS THE AREA. AMENDED TO BRING TAFS IN
LINE WITH OBS. PREVIOUS DISCUSSION FOLLOWS.
ISSUED AT 1132 PM EST TUE DEC 22 2015
SOME DRIER AIR WORKING ITS WAY IN FROM THE SOUTHEAST HAS SCATTERED OUT
SOME OF THE LOW CEILINGS THAT HAVE BEEN AFFECTING THE TERMINALS DURING
PARTS OF THE EVENING HOURS. THIS SHOULD BE TEMPORARY...AS WARM/MOIST
ADVECTION OVERRUNNING AN APPROACHING WARM FRONT SHOULD ALLOW FOR IFR
CONDITIONS TO DEVELOP AGAIN OVER THE NEXT SEVERAL HOURS. WILL KEEP IFR
CEILINGS IN THE FORECAST UNTIL THE MID TO LATE MORNING HOURS OF WEDNESDAY
WHEN THE BOUNDARY LAYER SHOULD MIX OUT ENOUGH TO ALLOW THE CEILINGS TO LIFT
INTO THE MVFR CATEGORY.
MODEL DATA SUGGEST INITIAL BAND OF ORGANIZED LIFT WILL BE MOVING INTO THE
WESTERN PARTS OF THE STATE TOWARDS 231700Z...SO EXPECTING RAIN/EMBEDDED
THUNDERSTORMS TO BEGIN AFFECTING THE TERMINALS FROM THE WEST TOWARDS MIDDAY
AND ON INTO THE AFTERNOON HOURS. RAINFALL MAY BE HEAVY ENOUGH FOR PERIODS OF
IFR VISIBILITY RESTRICTIONS.
SURFACE WINDS OVERNIGHT 130-160 DEGREES AT 6-9 KTS. PRESSURE GRADIENT REALLY
TIGHTENS UP BY MIDDAY WEDNESDAY IN THE WARM SECTOR...WITH SURFACE GUSTS AROUND
30 KTS PROBABLE.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...TUCEK
NEAR TERM...RYAN
SHORT TERM...TUCEK
LONG TERM...NIELD
AVIATION...JAS/NIELD
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1132 PM EST TUE DEC 22 2015
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 256 PM EST TUE DEC 22 2015
PATTERN TO REMAIN MILD THROUGH AND BEYOND THE SEVEN DAY FORECAST.
A COUPLE OF SIGNIFICANT STORMS SYSTEMS...WEDNESDAY WITH POTENTIAL
DAMAGING WIND...AND THIS WEEKEND...WITH HEAVY RAIN THAT MAY LEAD
TO FLOODING...WILL FINISH OUT THE ACTIVE WEATHER PATTERN LATE THIS
YEAR.
&&
.NEAR TERM /REST OF TONIGHT/...
ISSUED AT 1002 PM EST TUE DEC 22 2015
AFTER SOME SUNSHINE FOR MOST LATE THIS AFTERNOON...LOWER STRATUS
HAS ADVECTED BACK ACROSS MOST OF THE FORECAST AREA AS OF 03Z WITH
MOISTURE STREAMING NORTH AND INTERACTING WITH THE SHALLOW
INVERSION STILL PRESENT. FAR NORTHERN COUNTIES HAVE MANAGED TO
DROP QUICKLY INTO THE MID AND UPPER 30S THIS EVENING WHERE SKIES
HAVE REMAINED CLEAR THE LONGEST...WITH TEMPS RANGING FROM THE MID
40S TO LOWER 50S OVER MOST OF THE REST OF THE FORECAST AREA.
PIECES ALREADY STARTING TO ALIGN THAT WILL BRING THE WARM
TEMPERATURES WEDNESDAY ALONG WITH THE UNUSUAL SEVERE WEATHER RISK
FOR THE AFTERNOON AND EVENING WEDNESDAY. POLEWARD MOISTURE RETURN
OVER THE LAST 6 HOURS FROM THE GULF COAST HAS BEEN IMPRESSIVE TO
OUR SOUTH TO PUT IT MILDLY. 60+ DEGREE DEWPOINTS NOW WELL INTO THE
TENNESSEE VALLEY AND WILL LIKELY ADVANCE INTO KENTUCKY AFTER
MIDNIGHT. ALREADY SEEING PATCHY FOG IN THE LOWER WABASH VALLEY AS
THE DEEPER MOISTURE ARRIVES AND EXPECT THAT TO CONTINUE OVERNIGHT
IN SOME AREAS.
LOWS HAVE ALREADY BEEN MET...WITH TEMPERATURES STEADILY
CLIMBING FOR THE REST OF THE NIGHT AS WARM MOIST AIR SPREADS
NORTH. RAP AND NAM BOTH HINTING AT SURFACE TEMPS NEAR 60 OVER
SOUTHERN FORECAST AREA BY DAYBREAK AND CONSIDERING CURRENT TEMPS
OVER THE TENNESSEE AND LOWER MISSISSIPPI VALLEYS...THAT DOES NOT
SEEM FAR OFF.
CONVECTION ACROSS THE LOWER MISSISSIPPI VALLEY WILL RACE NORTHEAST
OVERNIGHT AND WHILE BULK OF THE ACTIVITY SHOULD REMAIN TO THE
SOUTHEAST OF THE FORECAST AREA...HI-RES GUIDANCE CONTINUING TO
CAPTURE SCATTERED SHOWERS INCREASING IN COVERAGE AFTER 06Z FROM
THE SOUTH AS WARM ADVECTION INTENSIFIES OVER THE OHIO VALLEY.
HAVE ADJUSTED POPS SLIGHTLY...BUT INTRODUCING LOW CHANCES FOR
ENTIRE FORECAST AREA FOR THE PREDAWN HOURS. MEANWHILE BACK TO THE
SOUTHWEST...EXPECT RAPID CONVECTIVE DEVELOPMENT OVER THE OZARKS AS
THE INTENSE LOW PRESSURE SWINGS OUT THROUGH THE CENTRAL PLAINS AND
BEGINS TO INTERACT WITH THE GULF MOISTURE FETCH. THIS WILL
CONTINUE TO INCREASE IN COVERAGE AND EXPAND INTO THE REGION BY MID
TO LATE MORNING WEDNESDAY.
ZONE AND GRID UPDATES OUT.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY/...
ISSUED AT 256 PM EST TUE DEC 22 2015
FORECAST ISSUE IS SEVERE WEATHER THREAT WEDNESDAY. THOUGH MODEL
DYNAMICS IN FAIRLY GOOD AGREEMENT...AMOUNT OF DESTABILIZATION
PRIOR TO MAIN SHOWER/SQUALL BAND ARRIVAL IN THE AFTERNOON MAY
DETERMINE HOW GUSTY CONVECTION MAY GET. MODEL SOUNDINGS SUGGEST
MIXING OF 40MPH GUSTS TO THE GROUND PRIOR TO ANY STORM LINE MAY
OCCUR AS WELL SO HAVE INCLUDED GUSTY WORDING IN THE FORECAST.
NAM SOMEWHAT DIFFERENT THAN OTHER MODELS IN HAVING QUITE DISTINCT
AND SIMILARLY POTENT ROUNDS OF STORMS...AFTERNOON AND THEN EVENING
WITH COLD FRONT TIED WITH TWO INSTABILITY AXES. WILL LEAN TOWARD
A BLEND OF MODELS AND FORECAST WORDING MAY NOT REFLECT THE
SEPARATION BUT TWO HEAVIER ROUNDS OF RAIN APPEAR POSSIBLE.
STRENGTH OF WARM ADVECTION SHOULD LEAD TO ADVERTISED RECORD OR
NEAR RECORD HIGHS IN THE UPPER 60S WEDNESDAY.
WEDNESDAY NIGHT...NAM IS SLOWEST WITH COLD FRONT WHILE GFS IS
QUITE FAST SO WILL AVERAGE BETWEEN THESE. END RESULT IS AT LEAST
ONE MORE DECENT SHOT OF RAIN WITH COLD FRONT PASSAGE DURING THE
EVENING WITH LINGERING SHOWERS ENDING BEFORE DAYBREAK.
THURSDAY AND PART OF FRIDAY...A DRY TRANQUIL PERIOD IS IN STORE
AS HIGH PRESSURE BUILDS IN BEHIND THE INTENSIFYING LOW THAT LIFTS
NE INTO THE HUDSON BAY AREA. HAVE KEPT TEMPERATURES NEAR GUIDANCE
AND STILL WELL ABOVE NORMAL WITH HIGHS MAINLY IN THE 50S AND LOWS
ABOVE FREEZING.
AS THE NEXT STRONG SHORTWAVE DUMPS INTO THE WESTERN TROUGH...THE
SURFACE BOUNDARY THAT SLIPPED INTO KENTUCKY THURSDAY WILL LIFT
BACK NORTH TO BEGIN THE NEXT RAINY PERIOD.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
ISSUED AT 232 PM EST TUE DEC 22 2015
ECMWF CONTINUES TO SUGGEST STRONG SOUTHWEST FLOW ALOFT OVER THE
EASTERN HALF OF THE UNITED STATES DURING THIS PERIOD...WITH MILD AND
MOIST GULF AIR FLOWING NORTH INTO THE OHIO VALLEY. A DEEP LOW
DEVELOPING OVER THE AMERICAN SOUTHWEST WILL GRADUALLY PUSH EAST
INTO TEXAS DURING THIS PERIOD...OCCASIONAL EJECTING WEAK SHORT
WAVES INTO THE SW FLOW ALOFT TOWARD THE OHIO VALLEY THROUGH
TUESDAY. MEANWHILE IN THE LOWER LEVELS A FRONTAL BOUNDARY IS
EXPECTED TO LINGER ACROSS CENTRAL INDIANA AND THE OHIO VALLEY
THROUGH MUCH OF THE PERIOD...PROVIDING A FOCUS FOR LOWER LEVEL
CONVERGENCE AND PRECIPITATION. THUS WILL AGAIN CONTINUE THE
ONGOING FORECAST THROUGH THE PERIOD WITH PLENTY OF POPS AND ABOVE
NORMAL TEMPERATURES.
&&
.AVIATION /DISCUSSION FOR THE 230600Z TAFS/...
ISSUED AT 1132 PM EST TUE DEC 22 2015
SOME DRIER AIR WORKING ITS WAY IN FROM THE SOUTHEAST HAS SCATTERED OUT
SOME OF THE LOW CEILINGS THAT HAVE BEEN AFFECTING THE TERMINALS DURING
PARTS OF THE EVENING HOURS. THIS SHOULD BE TEMPORARY...AS WARM/MOIST
ADVECTION OVERRUNNING AN APPROACHING WARM FRONT SHOULD ALLOW FOR IFR
CONDITIONS TO DEVELOP AGAIN OVER THE NEXT SEVERAL HOURS. WILL KEEP IFR
CEILINGS IN THE FORECAST UNTIL THE MID TO LATE MORNING HOURS OF WEDNESDAY
WHEN THE BOUNDARY LAYER SHOULD MIX OUT ENOUGH TO ALLOW THE CEILINGS TO LIFT
INTO THE MVFR CATEGORY.
MODEL DATA SUGGEST INITIAL BAND OF ORGANIZED LIFT WILL BE MOVING INTO THE
WESTERN PARTS OF THE STATE TOWARDS 231700Z...SO EXPECTING RAIN/EMBEDDED
THUNDERSTORMS TO BEGIN AFFECTING THE TERMINALS FROM THE WEST TOWARDS MIDDAY
AND ON INTO THE AFTERNOON HOURS. RAINFALL MAY BE HEAVY ENOUGH FOR PERIODS OF
IFR VISIBILITY RESTRICTIONS.
SURFACE WINDS OVERNIGHT 130-160 DEGREES AT 6-9 KTS. PRESSURE GRADIENT REALLY
TIGHTENS UP BY MIDDAY WEDNESDAY IN THE WARM SECTOR...WITH SURFACE GUSTS AROUND
30 KTS PROBABLE.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...TUCEK
NEAR TERM...RYAN
SHORT TERM...TUCEK
LONG TERM....PUMA
AVIATION...JAS
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1131 PM CST TUE DEC 22 2015
.SHORT TERM /TONIGHT/...
ISSUED AT 345 PM CST TUE DEC 22 2015
REMNANTS OF THE MORNING STRATUS SHIELD REMAIN OVER THE NORTHEASTERN
THIRD TO HALF OF THE STATE AND WILL GENERALLY REMAIN SO THIS EVENING
AS THE STRONG INVERSION REMAINS IN PLACE AND WE LOSE WHATS LEFT OF
ANY DAYTIME HEATING AND MIXING. AS A RESULT...CEILINGS AND
VISIBILITIES WILL CONTINUE TO BE LOW IN THOSE AREAS...AROUND 500
FEET AND A COUPLE MILES OR LESS RESPECTIVELY THROUGH THE SHORT TERM.
HAVE NOT CURRENTLY INTRODUCED FOG INTO THE GRIDS...BUT MAY WARRANT
SO DURING THE EVENING...ESPECIALLY FOR AREAS THAT HOLD OFF ON SEEING
PRECIP LONGER AND MOISTURE ADVECTION CONTINUES. AREAS THAT SAW
CLEARING WILL PROGRESSIVELY SEE HIGH BASED CLOUDS MOVE IN BEFORE
CEILINGS FALL AGAIN AS SURFACE LOW AND FORCING PROGRESSES TOWARDS
THE REGION FROM CENTRAL/EASTERN KANSAS.
THE AFOREMENTIONED SURFACE LOW WILL BE THE MAIN CONCERN IN THE SHORT
TERM...BEGINNING TO REALLY INFLUENCE THE AREA AFTER 03Z. THROUGH THE
DAY...NAM AND HRRR HAVE TENDED TO HANDLE THE CLEARING BEST...SO HAVE
TRENDED THAT WAY IN THE GRIDS FOR THIS EVENING. WITHIN THE SHORT
TERM WINDOW...BEST INITIAL FORCING IS THERMODYNAMIC WITH A GOOD PUSH
OF THETA-E ADVECTION ALONG WITH ISENTROPIC LIFT IN THE 290K REGION.
THE DEFORMATION ZONE WILL ALSO BEGIN TO SET UP IN NORTHWEST IOWA
AFTER 06Z...FURTHER BOOSTING LIFT. CURRENTLY...THE COLUMN IS QUITE
DRY FROM ABOUT 850MB TO 500MB...WHICH CALLS INTO SOME QUESTION WHEN
THE COLUMN WILL SATURATE AND PRECIP WILL BEGIN...BUT BEGAN TO UP
POPS IN NORTHWEST IOWA AROUND 5Z AND THROUGH THE SHORT TERM WINDOW
IN CONJUNCTION WITH HRRR/NAM SOLUTIONS.
.LONG TERM /WEDNESDAY THROUGH TUESDAY/...
ISSUED AT 345 PM CST TUE DEC 22 2015
THE LONG TERM REMAINS ACTIVE WITH SEVERAL SHORTWAVES EJECTING OUT
OF THE BAST OF A LONG WAVE TROUGH OUT WEST. WE BEGIN THE PERIOD
WITH THE SYSTEM AFFECTING THE SHORT TERM LIFTING NORTHEAST. THERE
WILL BE A BRIEF PERIOD OF OF SNOW ON THE BACKSIDE OF THIS SYSTEM
AS IT LIFTS OFF TO THE NORTHEAST. MOST OF THE FORCING EXITS BEFORE
THE CHANGEOVER SO I AM NOT LOOKING AT MUCH ACCUMULATION PLUS WE
WILL BE TOO WARM ALOFT...MAY EVEN SEE A BIT OF FREEZING RAIN WITH
THIS. ALSO...SOME INSTABILITY WORKS INTO EASTERN IOWA AS THIS
SYSTEM LIFTS OUT WHICH MEANS WE COULD SEE SOME ISOLATED THUNDER
WEDNESDAY AFTERNOON. AFTER THIS SYSTEM DEPARTS THERE WILL BE A
BRIEF RESPITE WEDNESDAY NIGHT BEFORE ANOTHER WEAK SHORTWAVE
TRANSLATES ACROSS THE SOUTH AND EAST. TEMPS WILL BE WARM ENOUGH
FOR RAIN WITH THIS SO NOT FORESEEING MUCH IN THE WAY OF TRAVEL
PROBLEMS BUT WITH RIVERS STILL VERY HIGH...ANY HEAVIER RAINFALL
WILL LIKELY RESULT IN FLOODING AGAIN.
THE NEXT MAIN SYSTEM WILL BE A DEEPENING LOW ACROSS THE SOUTHERN
PLAINS LIFTING NORTHEAST. I THINK THE MODELS ARE LIKELY TOO FAST
WITH THIS SYSTEM GIVEN HOW THE LOW IS DEEPENING BUT INITIALLY THIS
WILL BE A RAIN PRODUCER WITH COLD AIR WRAPPING INTO THE LOW
CHANGING PRECIP OVER TO SNOW. THIS ONE MAY BE A POTENTIAL SNOW
PRODUCER FOR US AND NEEDS TO BE WATCHED BUT WILL ALSO BRING
ADDITIONAL FLOODING THREATS.
&&
.AVIATION...23/06Z
ISSUED AT 1126 PM CST TUE DEC 22 2015
LOW PRESSURE SYSTEM WILL BRING RA TO SITES WITH CEILINGS AND
VISIBILITIES REMAINING MVFR AND LIKELY DROPPING TO IFR OR LIFR
WITH RA...GENERALLY BEYOND 12Z. EXPECT CONDITIONS TO IMPROVE
NEAR/AFTER 00Z AT SITES...THOUGH MVFR CEILINGS MAY LINGER. COULD
SEE SN AT NORTHERN SITES KMCW/KALO NEAR 00Z...BUT HAVE LEFT
MENTION OUT ATTM. WINDS WILL BE STRONG...SHIFTING TO THE NORTHWEST
AND BECOMING STRONG AND GUSTY NEAR/AFTER 00Z.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CURTIS
LONG TERM...FAB
AVIATION...AWB
AREA FORECAST DISCUSSION
National Weather Service Topeka KS
342 AM CST WED DEC 23 2015
.SHORT TERM...(Today and Tonight)
Issued at 301 AM CST WED DEC 23 2015
A few areas of weak vorticity maxima were rotating through the base
of the upper trough this morning. The first lobe has developed a
swath of showers lifting northward. Decent lapse rates in the low and
mid levels has generated enough weak instability for a few
thunderstorms over east central Kansas. This activity is expected
to exit into Nebraska before sunrise. Meanwhile, moisture advection
continues to increase ahead of a sfc low currently over southwest
Kansas. This could allow additional showers through mid afternoon as
the second lobe of vorticity deepens as it phases with the sfc low.
Mostly cloudy skies are anticipated with the sfc low encompassing
the area. Temperatures over north central Kansas today are expected
to cool to near 40 degrees as cloud cover increases and lingers
behind the sfc low. Further south, temps are steady in the lower
50s. The tightening pressure gradient with the sfc low will cause
southwesterly winds to increase between 15 and 20 mph sustained with
gusts near 30 mph.
This evening, skies clear temporarily before clouds return with
another small yet strong vorticity lobe shifts east over northern
Kansas and southern Nebraska. With the exception of
the NAM, the track of the axis would suggest areas of light rain
transitioning to snow are possible after midnight for areas along
and north of Interstate 70. Trace amounts are expected by Thursday
morning with perhaps up to an inch of snow near the Nebraska border.
Winds become light overnight as temps fall back to the upper 20s and
low 30s.
.LONG TERM...(Thursday through Tuesday)
Issued at 301 AM CST WED DEC 23 2015
Weak shortwave still forecast to graze the northern counties
through the morning on Thursday. Temperatures for that area in the
morning are still below freezing, and will carry light snow as
the precip type but not expecting much in the way of accumulation
as temperatures rise into the 40s for north central Kansas and
lower 50s for east central. Passage of that wave to our north does
aid in pushing weak frontal boundary temporarily into the area
with little sensible weather impacts. As this front lifts back
north on Friday and raises high temperatures a few degrees from
Thursdays numbers, could see some light rain showers in the
northern counties.
The reprieve is temporary however as next upper trof continues to
advance eastward, with one round of energy moving into the
northern plains and another piece dropping southward into the four
corners region. Leading northern wave advances a strong cold front
southward into the Central Plains. By 12z Saturday this front is
forecast by both EC and GFS to be just entering our western
counties, sweeping across eastern Kansas through the day Saturday.
Precipitation amounts with this feature are light, but without ice
in the column would likely come in the form of rain transitioning
to a light freezing rain/drizzle. This colder air continues to
feed southward through the night Saturday night into Sunday, with
enough lift continuing up and over the front over our area that
this light freezing precip may continue overnight into Sunday
morning. Model differences start to become significantly important
in this timeframe, as GFS has a saturated column and would bring
light accumulating snow toward Sunday morning, while EC has a warm
nose aloft and would continue a freezing rain profile. Both models
suggest a lull in precip for a short period of time Sunday before
noon as a mid level ridge moves over the area.
Differences in the forecast beyond 18z Sunday make forecasting
precipitation types a challenge this far out in the forecast. GFS
is taking a faster track with the upper low, lifting it from the
big bend of Texas through southeastern OK and into northern
Illinois by 0z Tuesday, and keeping our area now below freezing
and suggesting all snow for precipitation type Sunday night
through Monday evening, not to mention spitting out a respectable
snow band across the eastern counties through the day on Monday.
In the same time window of Sunday night through 0z Tuesday, the
EC takes the system from the big bend out only out to central
Oklahoma, wrapping more warm air into the system and changing
precip back over to rain across the southeast half of the forecast
area late Monday afternoon, while snow continues in the north
central counties. The GFS solution looks fast in how quickly it
ejects the system to the northeast, but the ensembles offer no
better idea either way on if a faster or slower solution is more
credible.
The takeaway at this point would be to be ready for the
potential of some type of a wintery mix on Saturday afternoon
through Sunday morning, with light accumulations possible. This in
and of itself could make for tricky traveling at those times.
Sunday day through Monday holds potential for all precipitation
types, including significant accumulating snow, or freezing rain,
or even some locally heavy rainfall for our east. Since the energy
associated with this system is still out off the Canadian Pacific
coast, it may be several more runs before guidance starts to
capture better concensus on this system.
&&
.AVIATION...(For the 06Z TAFS through 06Z Thursday) Issued at
1110 PM CST TUE DEC 22 2015
Main change to the forecast is to delay the onset of MVFR CIGS at
the terminals based on the RAP13. The preference is still for a
blend of the RAP and GFS for CIGS as the NAM continues to insist
on LIFR conditions. However there are no IFR CIGS upstream where
the NAM shows they should be now. The low clouds may scatter out
at TOP and FOE by the late morning only to move back in during the
afternoon as the upper low passes overhead. Timing this is low
confidence. Have a mention of VCSH thinking -RA will be more
scattered in nature at the terminals.
&&
.TOP Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...Bowen
LONG TERM...67
AVIATION...Wolters
AREA FORECAST DISCUSSION
National Weather Service Topeka KS
1110 PM CST TUE DEC 22 2015
...AVIATION UPDATE...
.SHORT TERM...(This Evening through Wednesday)
Issued at 305 PM CST TUE DEC 22 2015
Next system to affect eastern Kansas tonight and Wednesday was
located over the southern Rockies this afternoon at 20Z. The upper
trough moves into western Kansas tonight, then moves into eastern
Kansas by Wednesday morning before moving northeast Wednesday
afternoon. A surface front will move southeast into north central
Kansas by Wednesday morning. The front will then spread southeast
across the rest of the eastern Kansas as the surface low ejects
northeast in the afternoon. Models continue to show some light
precipitation developing late this evening with better forcing and
moisture transport after midnight into early Wednesday across
northeast and east central Kansas. Forecast soundings show some
elevated instability and lapse rates steepen beneath the upper trough
moving through. Parts of northeast and east central Kansas will
possibly see some isolated thunderstorms mainly late tonight through
the morning hours on Wednesday. Temperatures should be on the mild
side tonight with southerly winds keeping the lower boundary layer
mixed. There may be some clearing in the afternoon hours as the
system departs. Highs on Wednesday with clouds and cold advection
behind the cold front have kept high temperatures on the cool side
in the mid 40s to lower 50s.
.LONG TERM...(Wednesday Night through Tuesday)
Issued at 305 PM CST TUE DEC 22 2015
Bottom line up front: The storm this weekend has the potential to
bring heavy rains which could cause flooding, freezing rain which
could accumulate along with snow especially across central and
north central Kansas. The storm bears monitoring given the amount
of precip it could bring along with winds/temps as it passes by
come Monday.
In the Weds night time frame a shortwave will move across the area
bringing a chance for rain or snow. Soundings suggest mainly snow
north of I-70 however the lift is more focused into Nebraska and
given speed of system have opted to keep precip chcs near guidance
which suggests low precip chcs along the I-70 corridor with 30-40
pops north. QPF forecasts and snow ratios suggest any accums
should be less than one inch across our northern counties if any
accums did occur.
The focus then turns to the large storm that is now across the
Gulf of Alaska and is forecast to dive into the West through late
week. GFS and ECMWF have both struggled with consistency of the
system`s track and timing and based on the 12z runs they may
finally be converging on a solution that brings the upper low into
AZ/NM by Sat afternoon. Strong southerly flow between the upper
low and the unusually strong subtropical high east of FL should
draw up very high PWATS ahead of the storm. The focus for heaviest
rains Sat should set up just southeast of the CWA closer to the
Sfc-925mb boundary and hopefully it will remain there through
Sunday. The temp profile suggests rain would be precip type
through Saturday sundown before colder air begins to move into the
area behind the initial frontal wave. Forecast sfc temps and warm
nose profiles suggest a mix of snow, sleet or freezing rain
developing Sat night which could persist into Sunday depending on
sfc air temps which at this point are highly uncertain. What is
most likely is that we`d see little if any diurnal come Sunday
with the freezing line bisecting somewhere across the CWA. The
strongest forcing and heaviest precip will fall as the upper
system lifts out and tracks across the area Sunday night into
early Monday based on current model tracks. The precip types
remain uncertain but we are more confident that precip amounts as
the upper system lifts out could be 1 to 2 inches of liquid. That
may fall as rain, freezing rain or even snow depending on temp
profiles but takeaway is that all are possible within our CWA so
this storm bears close monitoring. All told the potential exists
for 1 to 3 inches of rain perhaps more across our southeast half
depending on the track of this system. At least some of that could
fall as freezing rain or snow which also suggests a heavy wet snow
event for central or north central KS. As mentioned...bottom line
is this could be a high impact storm for our CWA Sat night through
Monday.
&&
.AVIATION...(For the 06Z TAFS through 06Z Thursday) Issued at
1110 PM CST TUE DEC 22 2015
Main change to the forecast is to delay the onset of MVFR CIGS at
the terminals based on the RAP13. The preference is still for a
blend of the RAP and GFS for CIGS as the NAM continues to insist
on LIFR conditions. However there are no IFR CIGS upstream where
the NAM shows they should be now. The low clouds may scatter out
at TOP and FOE by the late morning only to move back in during the
afternoon as the upper low passes overhead. Timing this is low
confidence. Have a mention of VCSH thinking -RA will be more
scattered in nature at the terminals.
&&
.TOP Watches/Warnings/Advisories...NONE.
&&
$$
SHORT TERM...53
LONG TERM...Omitt
AVIATION...Wolters
AREA FORECAST DISCUSSION
NWS JACKSON KY
359 AM EST WED DEC 23 2015
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 343 AM EST WED DEC 23 2015
...SEVERE STORMS WITH DAMAGING WINDS POSSIBLE TONIGHT...
A RATHER ACTIVE...SPRING-LIKE PATTERN EXPECTED OVER THE NEXT 36
HOURS. PRESENTLY...A WARM FRONT IS LIFTING NORTH ACROSS TENNESSEE.
SOUTHEAST WINDS TO THE NORTH OF THE FRONT HAS KEPT MUCH OF EASTERN
KENTUCKY DRY OVERNIGHT. HOWEVER...THIS IS ABOUT TO CHANGE AS THE
FRONT CONTINUES TO PUSH NORTH THIS MORNING AND WINDS TURN MORE
SOUTHERLY. THE INITIAL SURGE OF MID LEVEL ISENTROPIC ASCENT HAS
GENERATED A LARGER POCKET OF RAINFALL OVER THE CUMBERLAND
PLATEAU...AND THIS RAIN WILL MOVE NORTH ACROSS OUR WESTERN
COUNTIES THROUGH 7 AM. INCREASED POPS TO CATEGORICAL WITH THIS
RAIN SPREADING NORTH. TO THE EAST...WE SHOULD REMAIN WITH VERY
LITTLE AS THE DOWNSLOPING CONTINUES TO EAT AWAY AT SHOWERS TRYING
TO PUSH NORTH. EVENTUALLY THE DRY AIR WILL BE OVERCOME...LIKELY
AROUND OR SHORTLY AFTER 7 AM...WITH SCATTERED SHOWERS PUSHING
NORTH ACROSS THE REGION THROUGH THE MORNING. HRRR HAS BEEN
CONSISTENT ON LINGERING SHOWERS INTO THE AFTERNOON...SO HAVE
KEPT POPS IN THE FORECAST THROUGH EARLY AFTERNOON. IT DOES APPEAR
WE SHOULD SEE A BETTER BREAK IN PRECIPITATION BY LATE AFTERNOON
THROUGH THE EARLY EVENING HOURS..AS SUBSIDENCE SPREADS IN AHEAD OF
THE APPROACHING COLD FRONT.
WITH THE FRONT APPROACHING THIS AFTERNOON...THE GRADIENT SHOULD
INCREASE AND WE WILL SEE GUSTY WINDS DEVELOP AREAWIDE. THE NAM
BUFKIT MOMENTUM TRANSFER EQUATION SUPPORTS 3O TO 35 MPH WIND
GUSTS...ESPECIALLY OUT ACROSS CENTRAL KENTUCKY...EXTENDING ACROSS
THE BLUEGRASS. WIND GUSTS UP TO 25 WILL REMAIN POSSIBLE TO THE
EAST. PUT IN A MENTION IN THE HWO OF THE GUSTY WINDS THIS
AFTERNOON.
FINALLY...MOVING ONTO THE SEVERE POTENTIAL TONIGHT. MODELS ARE
STILL NOT IN GREAT AGREEMENT ON OVERALL TIMING...AS A FEW OF THE
HI-RES MODELS SUPPORT AN EARLIER ROUND OF CONVECTION IN THE
EVENING...WHILE OTHERS HOLD OFF UNTIL OVERNIGHT. THUS...CONFIDENCE
IS HIGH ON THE THREAT FOR SEVERE STORMS OCCURRING TONIGHT...THERE
REMAINS CONSIDERABLE SPREAD ON WHETHER IT OCCURS MID TO LATE
EVENING OR AFTER MIDNIGHT. REGARDLESS OF TIMING...SHEAR GENERATED
WITH THE STRENGTH OF THE LOW LEVEL JET IS TREMENDOUS AND WILL
SUPPORT THE SEVERE STORM POTENTIAL. THE EXACT QUESTION IS HOW MUCH
INSTABILITY WILL BE PRESENT AS THE STORMS CROSS INTO EASTERN
KENTUCKY TONIGHT. NAM BUFKIT SOUNDINGS SHOW SOME POTENTIAL FOR
600-1000J/KG OF SBCAPE...WHICH IS MARGINAL...BUT COULD BE ENOUGH
TO ALLOW WINDS TO REACH THE SURFACE...ESPECIALLY IF WE END UP
DEALING WITH MORE LINE SEGMENTS. THUS...THE STORM PREDICTION
CENTER HAS EXPANDED THE ENHANCED RISK OF SEVERE STORMS INTO
CENTRAL KENTUCKY. IF WE DO END UP WITH A LINE OF STORMS
(QLCS)...A SPIN UP TORNADO WOULD ALSO BE POSSIBLE ALONG THE LINE
WITH SUCH STRONG SHEAR NEARLY NORMAL TO THE ADVANCING STORMS. WILL
CONTINUE TO HIGHLIGHT DAMAGING WINDS/TORNADO THREAT IN THE HWO AND
PLAN TO DO A MORNING WEB BRIEFING TO HIGHLIGHT THE THREAT.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 359 AM EST WED DEC 23 2015
THE MODELS REMAIN IN GOOD GENERAL AGREEMENT WITH THE AMPLIFIED AND
ACTIVE LONG WAVE PATTERN THROUGH EARLY NEXT WEEK...AS THE SUMMER-
LIKE BERMUDA HIGH VERY GRADUALLY SHIFTS TOWARDS THE BAHAMAS BY
EARLY NEXT WEEK. MEANWHILE...DEEP AND BROAD TROUGHING IN THE
WESTERN HALF OF THE NATION TRANSITIONS TO SPLIT FLOW BY THE
HOLIDAY WEEKEND. A CUTOFF LOW WILL DROP SOUTHEAST INTO
TEXAS/MEXICO...AND THEN SWING NORTHEAST INTO THE PLAINS AND
EVENTUALLY GREAT LAKES/OHIO VALLEY REGIONS BY EARLY NEXT WEEK.
NEAR RECORD TO RECORD TEMPERATURES AT TIMES...ALONG WITH SEVERAL
ROUNDS OF WET WEATHER STILL LOOK IN THE OFFING FOR THE OHIO AND
TENNESSEE VALLEYS THROUGH THE PERIOD.
A FRONTAL BOUNDARY WILL BE STALLING ACROSS OUR AREA THURSDAY
NIGHT...WITH A SURGE OF LOW LEVEL MOISTURE COMING IN BY FRIDAY
MORNING. CONFIDENCE REGARDING HOW MUCH RAINFALL WE WILL SEE
FRIDAY INTO FRIDAY NIGHT AS THE FRONTAL BOUNDARY GRADUALLY LIFTS
NORTH AS A WARM FRONT CONTINUES TO BE ON THE LOW SIDE. PWATS ARE
VERY HIGH...HOWEVER MID AND UPPER LEVEL SUPPORT IS NOT THAT
IMPRESSIVE...SO AM NOT CONVINCED THAT THE MAJORITY OF THE MOISTURE
WILL BE TAPPED DESPITE THE AMPLE LOW LEVEL JET IN PLACE. AS
SUCH...HAVE CONTINUED TO KEEP THINGS GENERALIZED CONCERNING THE
FLOOD POTENTIAL UNTIL THERE IS BETTER MODEL AGREEMENT.
THE BAROCLINIC ZONE WILL SHIFT NORTH OF OUR AREA BY LATE SATURDAY
INTO SATURDAY NIGHT...LEADING TO LESSER CHANCES OF POPS ACROSS OUR
AREA. THE MODELS HAVE BEEN WAFFLING SUNDAY INTO MONDAY...WITH THE
ECMWF SUGGESTING A NORTHERN STREAM TROUGH HAVING ENOUGH PUSH TO
SEND THE BOUNDARY BACK ACROSS OUR AREA ON SUNDAY...AND THEN
HOLDING BACK THE NEXT FRONT UNTIL MAINLY TUESDAY. THE GFS HAS A
LITTLE BETTER CONTINUITY...KEEPING THE BOUNDARY JUST TO OUR
NORTH...UNTIL THE NEXT SURGE OF MOISTURE ARRIVES MONDAY NIGHT.
GIVEN THE UNCERTAINTY...STUCK FAIRLY CLOSE TO THE BLENDED
GUIDANCE...ALTHOUGH DID LINGER POPS A BIT LONGER INTO TUESDAY TO
ALLOW FOR A POTENTIAL SLOWER EXIT.
THE BEST CHANCE TO TEST RECORD HIGHS STILL LOOK TO BE SATURDAY AND
SUNDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 122 AM EST WED DEC 23 2015
DOWNSLOPING FLOW WILL LIKELY KEEP VFR CONDITIONS AT THE TAF SITES
THROUGH MOST OF THE NIGHT. SOME MVFR COULD SNEAK IN AT
TIMES...ESPECIALLY NEAR KSME...BUT SHOULD PREDOMINANTLY BE VFR.
SOME SHOWERS MAY WORK ACROSS THE AREA AFTER DAYBREAK...WITH
PERHAPS A BRIEF PERIOD OR TWO OF MVFR CIGS. OTHERWISE...VFR
CONDITIONS WILL RETURN BY THE AFTERNOON. LOW LEVEL WINDS WILL RAMP
UP OVERNIGHT...SO INCLUDED SOME LOW LEVEL WIND SHEAR. WINDS WILL
TURN GUSTY AGAIN THIS AFTERNOON THROUGH THE EVENING AS THE
GRADIENT INCREASED AHEAD OF AN APPROACHING COLD FRONT. THIS FRONT
WILL SEND A LINE OF STRONG...POSSIBLY SOME SEVERE...STORMS ACROSS
THE AREA OVERNIGHT TONIGHT...WITH THE MAIN THREAT BEING DAMAGING
WINDS.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...KAS
LONG TERM...GEOGERIAN
AVIATION...KAS
AREA FORECAST DISCUSSION
NWS JACKSON KY
343 AM EST WED DEC 23 2015
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 343 AM EST WED DEC 23 2015
...SEVERE STORMS WITH DAMAGING WINDS POSSIBLE TONIGHT...
A RATHER ACTIVE...SPRING-LIKE PATTERN EXPECTED OVER THE NEXT 36
HOURS. PRESENTLY...A WARM FRONT IS LIFTING NORTH ACROSS TENNESSEE.
SOUTHEAST WINDS TO THE NORTH OF THE FRONT HAS KEPT MUCH OF EASTERN
KENTUCKY DRY OVERNIGHT. HOWEVER...THIS IS ABOUT TO CHANGE AS THE
FRONT CONTINUES TO PUSH NORTH THIS MORNING AND WINDS TURN MORE
SOUTHERLY. THE INITIAL SURGE OF MID LEVEL ISENTROPIC ASCENT HAS
GENERATED A LARGER POCKET OF RAINFALL OVER THE CUMBERLAND
PLATEAU...AND THIS RAIN WILL MOVE NORTH ACROSS OUR WESTERN
COUNTIES THROUGH 7 AM. INCREASED POPS TO CATEGORICAL WITH THIS
RAIN SPREADING NORTH. TO THE EAST...WE SHOULD REMAIN WITH VERY
LITTLE AS THE DOWNSLOPING CONTINUES TO EAT AWAY AT SHOWERS TRYING
TO PUSH NORTH. EVENTUALLY THE DRY AIR WILL BE OVERCOME...LIKELY
AROUND OR SHORTLY AFTER 7 AM...WITH SCATTERED SHOWERS PUSHING
NORTH ACROSS THE REGION THROUGH THE MORNING. HRRR HAS BEEN
CONSISTENT ON LINGERING SHOWERS INTO THE AFTERNOON...SO HAVE
KEPT POPS IN THE FORECAST THROUGH EARLY AFTERNOON. IT DOES APPEAR
WE SHOULD SEE A BETTER BREAK IN PRECIPITATION BY LATE AFTERNOON
THROUGH THE EARLY EVENING HOURS..AS SUBSIDENCE SPREADS IN AHEAD OF
THE APPROACHING COLD FRONT.
WITH THE FRONT APPROACHING THIS AFTERNOON...THE GRADIENT SHOULD
INCREASE AND WE WILL SEE GUSTY WINDS DEVELOP AREAWIDE. THE NAM
BUFKIT MOMENTUM TRANSFER EQUATION SUPPORTS 3O TO 35 MPH WIND
GUSTS...ESPECIALLY OUT ACROSS CENTRAL KENTUCKY...EXTENDING ACROSS
THE BLUEGRASS. WIND GUSTS UP TO 25 WILL REMAIN POSSIBLE TO THE
EAST. PUT IN A MENTION IN THE HWO OF THE GUSTY WINDS THIS
AFTERNOON.
FINALLY...MOVING ONTO THE SEVERE POTENTIAL TONIGHT. MODELS ARE
STILL NOT IN GREAT AGREEMENT ON OVERALL TIMING...AS A FEW OF THE
HI-RES MODELS SUPPORT AN EARLIER ROUND OF CONVECTION IN THE
EVENING...WHILE OTHERS HOLD OFF UNTIL OVERNIGHT. THUS...CONFIDENCE
IS HIGH ON THE THREAT FOR SEVERE STORMS OCCURRING TONIGHT...THERE
REMAINS CONSIDERABLE SPREAD ON WHETHER IT OCCURS MID TO LATE
EVENING OR AFTER MIDNIGHT. REGARDLESS OF TIMING...SHEAR GENERATED
WITH THE STRENGTH OF THE LOW LEVEL JET IS TREMENDOUS AND WILL
SUPPORT THE SEVERE STORM POTENTIAL. THE EXACT QUESTION IS HOW MUCH
INSTABILITY WILL BE PRESENT AS THE STORMS CROSS INTO EASTERN
KENTUCKY TONIGHT. NAM BUFKIT SOUNDINGS SHOW SOME POTENTIAL FOR
600-1000J/KG OF SBCAPE...WHICH IS MARGINAL...BUT COULD BE ENOUGH
TO ALLOW WINDS TO REACH THE SURFACE...ESPECIALLY IF WE END UP
DEALING WITH MORE LINE SEGMENTS. THUS...THE STORM PREDICTION
CENTER HAS EXPANDED THE ENHANCED RISK OF SEVERE STORMS INTO
CENTRAL KENTUCKY. IF WE DO END UP WITH A LINE OF STORMS
(QLCS)...A SPIN UP TORNADO WOULD ALSO BE POSSIBLE ALONG THE LINE
WITH SUCH STRONG SHEAR NEARLY NORMAL TO THE ADVANCING STORMS. WILL
CONTINUE TO HIGHLIGHT DAMAGING WINDS/TORNADO THREAT IN THE HWO AND
PLAN TO DO A MORNING WEB BRIEFING TO HIGHLIGHT THE THREAT.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 343 AM EST WED DEC 23 2015
LONG TERM DISCUSSION WILL FOLLOW SHORTLY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 122 AM EST WED DEC 23 2015
DOWNSLOPING FLOW WILL LIKELY KEEP VFR CONDITIONS AT THE TAF SITES
THROUGH MOST OF THE NIGHT. SOME MVFR COULD SNEAK IN AT
TIMES...ESPECIALLY NEAR KSME...BUT SHOULD PREDOMINANTLY BE VFR.
SOME SHOWERS MAY WORK ACROSS THE AREA AFTER DAYBREAK...WITH
PERHAPS A BRIEF PERIOD OR TWO OF MVFR CIGS. OTHERWISE...VFR
CONDITIONS WILL RETURN BY THE AFTERNOON. LOW LEVEL WINDS WILL RAMP
UP OVERNIGHT...SO INCLUDED SOME LOW LEVEL WIND SHEAR. WINDS WILL
TURN GUSTY AGAIN THIS AFTERNOON THROUGH THE EVENING AS THE
GRADIENT INCREASED AHEAD OF AN APPROACHING COLD FRONT. THIS FRONT
WILL SEND A LINE OF STRONG...POSSIBLY SOME SEVERE...STORMS ACROSS
THE AREA OVERNIGHT TONIGHT...WITH THE MAIN THREAT BEING DAMAGING
WINDS.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...KAS
LONG TERM...GEOGERIAN/KAS
AVIATION...KAS
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
135 AM EST WED DEC 23 2015
.SYNOPSIS...
A STEADY FEED OF MOISTURE ON THE BACK SIDE OF HIGH PRESSURE OVER
THE WESTERN ATLANTIC WILL KEEP THE UNSEASONABLY WARM AND UNSETTLED
CONDITIONS ACROSS THE AREA THROUGH THURSDAY. A WEAK COLD FRONT
APPROACHES LATE THURSDAY...THEN STALLS ACROSS THE AREA THROUGH
THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
VRB LYRD CLDNS OVR THE FA THIS EVE. (SCT) -RA CONTG TO MOVE NE
ACRS MOSTLY NE NC ATTM. WIDESPREAD ST (CIGS 500-1500FT) MNLY ACRS
FM I 95 ON W...ALG W/ PATCHY FG. 00Z/23 RUC HAS AREA OF RA
BLOSSOMING FM SCNTRL VA S THROUGH WRN PORTION OF NC AFT
MDNGT...WHICH CONTS TO SPREAD TO THE N AND NE THROUGH THE REST OF
THE NGT. MEANWHILE...RA WILL RMN LIKELY INVOF THE CST. WILL NEED
TO MONITOR FG...ESP INLAND...THOUGH RIGHT NOW XPCG MOSTLY LO ST
OVR WIDESPREAD FG. LO TEMPS IN THE U50S TO ARND 60F.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH FRIDAY/...
SAID S/W PROGGED TO TRACK NE ALONG THE SPINE OF THE MTS WED. THIS
SYSTM TAPS COPIOUS AMTS OF GOM MSTR AND DRIVES IT NE. MSTR OFF THE
ATLNTC GETS ENTRAINED INTO THE SYSTM AS WELL. APPEARS THE BULLSEYE
FOR THE HEAVIEST RAINFALL WILL BE ACROSS THE MTS. FOR AKQ FA...THIS
WUD MOST AFFECT THE VA PIEDMONT MAINLY WEST OF I95 WHERE BTWN 1 TO
1.5 INCHES WILL BE PSBL (HIGHEST OUT NR LKU-FVX). RAINFALL TDY WAS
ARND AN INCH. AFTR THE COORD CALL AND GIVEN THE QUICK MOVMNT OF THE
HEAVIEST AXIS OF RAINFALL WED...NO FLOOD PRODUCTS WILL BE ISSUED
WITH THIS PACKAGE. THE RUNOFF WILL LIKELY END UP IN THE RIVERS
RAISING LEVELS OVER THE NEXT FEW DAYS.
AS THE BEST OMEGA LIFTS NORTH WED AFTRN...PCPN BECOMES SOMEWHAT MORE
CONVECTIVE THAN STRATIFORM GIVEN THE UNUSUAL WARM AIRMASS. NOT
MUCH INSTABILITY PROGGED...BUT CAN NOT RULE OUT ELVATED THUNDER
DRNG THE AFTR AS WAVES OF PCPN TRAVERSE EAST DUE TO LINGERING
TROFINESS. DESPITE THE CLOUDS/PCPN...TMPS APPRCH RECORD LEVELS IN
SOME AREAS. HIGHS 70-75.
MAIN LOW LIFTS NORTH INTO SRN NEW ENGLAND WED NITE. COPIOUS AMTS OF
MSTR REMAIN ACROSS THE FA DUE TO WEAK DISTURBANCES MOVG NE. TSCTNS
LOADED WITH ENUF MSTR TO KEEP CHC/LIKELY POPS GOING. FOG WILL BECOME
AN ISSUE ONCE AGAIN. WARM AND RTHR HUMID WITH LOWS IN THE M-U60S.
MODELS SHOWING AKQ FA IN A WARM SECTOR SCENARIO FOR X-MAS EVE AHEAD
OF THE APPRCHG BNDRY TO THE NW. NOT MUCH SPRT FOR PCPN UNTIL THE
AFTRN WHERE SCT CONVECTION IS PSBL GIVEN THE AVAILABLE MSTR AND
ADVANCING BNDRY. HIGHS WILL ALL DEPEND ON HOW MUCH SUN DVLPS...BUT
ALL DATA SHOWING SUMMER LIKE READINGS WITH HIGHS 75-80. IT IS NOT A
QUESTION ON WHETHER WE SET NEW RECORD HIGH TMPS...BUT BY HOW MUCH???
WILL FEEL MORE LIKE LABOR DAY THAN X-MAS EVE.
CHC POPS THU NITE ALONG WITH MORE FOG PTNTL AS THE BNDRY WEAKENS BUT
LINGERS ACROSS THE AREA. WARM AND HUMID ONCE AGAIN WITH LOWS U50S
NORTH TO M60S SOUTH.
MODELS DIFFER FRI ON JUST WHERE THE BNDRY ENDS UP. CONSENSUS IS FOR
IT TO SAG SOUTH AS A BKDR COLD FRNT TO NE THE VA/NC BORDER. ENUF
MSTR TO KEEP CHC POPS IN FCST. NOT AS WARM...BUT STILL WELL ABV
NRML. WINDS TURN NORTH FOR A SHORT TIME ALLOWING SOMEWHAT COOLER
AIR TO FILTER SOUTH. HIGHS RANGE FROM THE M-U60S OVER THE ERN
SHORE...L- M70S ELSEWHERE. THESE VALUES FALLING JUST SHY OF THE
RECORD HIGHS FOR X-MAS DAY.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
THE LONG TERM PERIOD WILL FEATURE A CONTINUATION OF WARM TEMPS AND
CHANCES FOR SHOWERS. RIDGING OVER THE SOUTHEASTERN STATES WILL
PREVENT SIGNIFICANT AIR MASS CHANGES. A WEAK FRONTAL BOUNDARY WILL
BE OVER THE MID ATLANTIC STATES DURING THE LONG TERM PERIOD. THERE
IS GENERALLY A 30 PERCENT CHANCE FOR PCPN ALTHOUGH THESE SHOWERS
CHANCES DROP OFF SATURDAY NIGHT AND SUNDAY AND THEN INCREASE ONCE
AGAIN SUNDAY NIGHT THROUGH TUESDAY. PCPN IS NOT EXPECTED TO BE
WIDESPREAD.
HIGH TEMPERATURES WILL GENERALLY RUN IN THE 60S TO LWR 70S EXCEPT
EXCEPT UPR 50S TO 60S ON MONDAY. LOWS ARE FORECAST TO RANGE IN THE
UPR 40S TO 50S NORTH PORTIONS AND 50S TO NEAR 60 PORTIONS.
&&
.AVIATION /07Z WEDNESDAY THROUGH SUNDAY/...
CONDITIONS ARE NOW MAINLY IFR/LIFR ALL SITES IN A COMBINATION OF
REDUCED VSBYS THAT AVG 1-3SM AND LOW CLOUDS WITH CIGS THAT AVG
200-1000 FT. CHANCES FOR RAIN INCREASE THROUGH THE NEXT FEW HRS AS
WELL.
PERIODS OF SHOWERS WITH PSBL IFR WILL CONTINUE LATER
TODAY...THOUGH CONDITIONS SHOULD GRADUALLY IMPROVE BETWEEN 15-18Z. EXPECT
WIND GUST UP TO 20-25 KT ACRS SE VA/NE NC THIS AFTN...AND ALL
AREAS TONIGHT/THU MORNING. THIS STRENGTHENING PRESSURE GRADIENT
SHOULD ACT TO INHIBIT FOG DEVELOPMENT AND KEEP VSBYS UP TONIGHT/THU
MORNING BUT SOME LOWER CIGS WILL STILL BE POSSIBLE.
OUTLOOK...A WEAK FRONTAL BOUNDARY WILL BE IN THE VICINITY OF THE
MID ATLANTIC STATES BEGINNING FRIDAY. ASIDE FROM PCPN...PATCHY IFR
CONDITIONS WILL BE PSBL IN THE OUTLOOK PERIOD DURING THE PREDAWN
THROUGH MID MORNING HOURS FRI/SAT DUE TO LOW STRATUS AND FOG (BUT
SHOULD NOT BE AS WIDESPREAD AS WED MORNING).
&&
.MARINE...
SOUTH TO SOUTHWEST WINDS WILL PREVAIL OVER THE MARINE AREA
THROUGH EARLY FRIDAY. SEAS IN THE NORTHERN COASTAL WATERS HAVE
FALLEN BELOW 5 FT.
THE PRESSURE GRADIENT TIGHTENS LATE WEDNESDAY AS MESO SCALE LOW
PRESSURE DEVELOPS OVER WEST VIRGINIA AS DEPICTED BY THE NAM.
SOUTHERLY WINDS ARE FORECAST TO INCREASE AND PRODUCE SCA OVER THE
BAY...LOWER JAMES AND CURRITUCK SOUND STARTING AT 18Z. SCA ALSO
STARTS IN THE COASTAL WATERS AT 21Z AS SEAS ARE EXPECTED TO BUILD TO
5 TO 6 FT. CURRENT ADVISORY S OF PARRAMORE ISLAND WILL NEED TO BE
EXTENDED NORTH WHEN THE CURRENT ADVISORY EXPIRES.
WHILE THE WINDS OVER INLAND WATERS DIMINISH ALLOWING THE SCA TO END
AROUND 06Z THURSDAY...THE SCA IN THE COASTAL WATERS WILL CONTINUE AS
SEAS STAY 5 FT OR HIGHER THROUGH MUCH OF THURSDAY.
WINDS DIMINISH FRIDAY AS A WEAK FRONTAL BOUNDARY DROPS INTO THE
REGION. PRESSURE GRADIENT WILL BE WEAK ALONG THE BOUNDARY. CURRENT
INDICATIONS HAVE SEAS BUILDING EARLY NEXT WEEK DUE TO A PROLONGED
PERIOD OF ONSHORE WINDS.
&&
.CLIMATE...
CORRECTED
RECORD HIGH TEMPS FOR DEC 23RD:
RIC...73 IN 1990
ORF...77 IN 1990
SBY...71 IN 1990
ECG...76 IN 2013
RECORD HIGH TEMPS FOR DEC 24TH: RECORD HIGH MIN TEMPS FOR DEC 24TH:
RIC...71 IN 1988 RIC...49 IN 1979
ORF...75 IN 1891 ORF...59 IN 1891
SBY...70 IN 2014 SBY...50 IN 2014
ECG...75 IN 1990 ECG...58 IN 1956
RECORD HIGH TEMPS FOR DEC 25TH: RECORD HIGH MIN TEMPS FOR DEC 25TH:
RIC...74 IN 1955 RIC...58 IN 1964
ORF...75 IN 1964 ORF...59 IN 1964
SBY...73 IN 1932 SBY...60 IN 1964
ECG...75 IN 1955 ECG...56 IN 1964
ALL TIME HIGH TEMPS FOR DEC:
RIC...81 IN 1998
ORF...81 IN 2013
SBY...77 IN 2013
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 1 PM THIS AFTERNOON TO 1 AM EST
THURSDAY FOR ANZ630>634-638.
SMALL CRAFT ADVISORY FROM 4 PM THIS AFTERNOON TO 4 PM EST
THURSDAY FOR ANZ650-652-654-656-658.
&&
$$
SYNOPSIS...ALB/MPR
NEAR TERM...ALB
SHORT TERM...MPR
LONG TERM...LSA
AVIATION...LKB/DAP
MARINE...LSA
CLIMATE...AKQ
AREA FORECAST DISCUSSION
NWS DULUTH MN
1144 PM CST TUE DEC 22 2015
.UPDATE...
ISSUED AT 902 PM CST TUE DEC 22 2015
MINIMUM TEMPERATURE FORECAST HAS BEEN MET AND TEMPS CONTINUE TO
WARM. HAVE ADJUSTED THE FORECAST TO ACCOUNT FOR SLOWLY RISING
TEMPS TONIGHT. WITH THE WARM TEMPS TO START WEDNESDAY...WITH
SEVERAL SPOTS ABOVE FREEZING...REMOVED THE MENTION OF FREEZING
DRIZZLE AND SLEET.
UPDATE ISSUED AT 746 PM CST TUE DEC 22 2015
SFC LOW CENTER HAS MOVED INTO SE ND AND THE LIGHT SNOW HAS ENDED.
SFC TEMPS HAVE WARMED TO 32F OR WARMER IN SEVERAL SPOTS. AS A
RESULT...HAVE REMOVED THE MENTION OF FREEZING
DRIZZLE...SLEET...DRIZZLE. STILL EXPECTING THE NEXT ROUND OF SNOW
TO DEVELOP IN NW WI AFTER MIDNIGHT. HOWEVER...SHORT TERM HIRES
MODELS INCLUDING THE DLH WRF AND HRRR ARE POINTING TO THE
POSSIBILITY OF ALL RAIN IN NW WI OR A RAIN SNOW MIX. WILL KEEP THE
PREDOMINATE PTYPE AS SNOW. MADE SOME OTHER MINOR ADJUSTMENTS.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 413 PM CST TUE DEC 22 2015
THIS AFTERNOON A COMPACT SHORTWAVE TROF STRETCHED FROM NORTHEAST
MONTANA INTO EASTERN SOUTH DAKOTA. THE TROF WAS ACCOMPANIED BY A
POTENT CYCLONIC VORTICITY ANOMALY AND STRONG WARM AIR ADVECTION.
AT THE SURFACE A CLOSE LOW WAS CENTERED OVER NORTHERN SOUTH DAKOTA
WITH A TROF OF LOW PRESSURE STRETCHING NORTHEASTWARD INTO
NORTHWEST ONTARIO. LIGHT...TO OCCASIONALLY MODERATE...SNOW WAS
FALLING OVER EASTERN NORTH DAKOTA AND NORTHWEST MINNESOTA. SNOW
SHOWERS AND AREAS OF FREEZING DRIZZLE STRETCHED FARTHER EASTWARD
INTO NORTHEAST MINNESOTA.
THE SHORTWAVE TROF AND ASSOCIATED SURFACE LOW WILL LIFT THROUGH
NORTHWEST MINNESOTA AND INTO ONTARIO TONIGHT. PATCHY AREAS OF
FREEZING DRIZZLE ARE EXPECTED TO CONTINUE OVER MUCH OF NORTHEAST
MINNESOTA THANKS IN LARGE PART TO A WEDGE OF DRY AIR BETWEEN THE
GLACIATED CLOUDS ALOFT AND THE SATURATED NEAR-SURFACE LAYER. THE
FREEZING DRIZZLE WILL CHANGE TO OR MIX WITH LIGHT SNOW OVER MY
WESTERN ZONES AS THE SYSTEM PASSES BY. SNOW ACCUMULATION SHOULD
BE LIGHT...AS THE BEST FORCING FOR ASCENT WILL QUICKLY MOVE
THROUGH ANY SPECIFIC LOCATION. LOOK FOR SNOW TOTALS IN THE DUSTING
TO 2 INCH RANGE...WITH THE HIGHEST ACCUMULATION OVER WESTERN
PORTIONS OF KOOCHICHING COUNTY.
ATTENTION THEN SHIFTS TO WEDNESDAY...AS A SECONDARY AREA OF LOW
PRESSURE LIFTS FROM THE CENTRAL PLAINS INTO NORTHERN WISCONSIN BY
LATE WEDNESDAY AFTERNOON. DETERMINISTIC AND ENSEMBLE GUIDANCE IS
ALL POINTING TOWARD STRONG WARM AIR ADVECTION AHEAD OF AND EAST OF
THE LOW...AND SURFACE TEMPERATURES OVER WISCONSIN CLIMBING INTO
THE UPPER 30S TO LOW 40S. WITH THE WARM ADVECTION AND ISENTROPIC
ASCENT...AND ASSOCIATED PRECIPITATION... AM CONCERNED GUIDANCE MAY
BE TRENDING TOO WARM WITH SFC TEMPS. HAVE TRENDED CLOSER TO THE
DETERMINISTIC NAM GUIDANCE FOR TEMPS ON WEDNESDAY...WHICH YIELDS
30-35F FOR MAX TEMPS.
PRECIP TYPES ARE A CHALLENGE FOR WEDNESDAY. THE AIRMASS WILL BE
COLD ENOUGH FOR SNOW...WITH PATCHY FREEZING DRIZZLE...OVER MY
MINNESOTA ZONES. HOWEVER...ASCENT IS MUCH WEAKER AND DO NOT EXPECT
MORE THAN FLURRIES AND FREEZING DRIZZLE THROUGH THE AFTERNOON.
WHERE PRECIPITATION IS LIKELY TO BE HEAVIEST...MAINLY FROM THE
TWIN PORTS SOUTH ALONG I-35 AND EASTWARD...A WINTRY MIX OF SNOW...
SLEET...AND RAIN SEEMS FAVORED. SHOULD TEMPERATURES REMAIN
COOLER...AND IF THE ADVECTION ALOFT TRENDS CLOSER TO THE GFS
SOLUTION...FREEZING RAIN WOULD BE MORE OF A CONCERN. BETWEEN THE
SLEET AND SNOW POTENTIAL...THERE IS A THREAT FOR SOME ICY ROADS.
DUE TO THE LINGERING UNCERTAINTY IN PTYPE AND TEMPERATURES...HELD
OFF ON AN ADVISORY FOR NOW BUT ONE MAY BE NEEDED BY MORNING.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 413 PM CST TUE DEC 22 2015
BY WEDNESDAY EVENING THE SFC LOW WILL BE RACING OFF TO THE
NORTHEAST...AND ITS WHEREABOUTS DEPEND UPON THE MODEL AND HAVE
USED THE GFS/ECMWF COMPROMISE OF THE SLOWER MOVEMENT. THE
CYCLONIC FLOW AROUND THE LOW WILL KEEP SNOW SHOWERS GOING INTO
THURSDAY MORNING. THEY WILL END IN THE AFTERNOON. HOWEVER...THERE
COULD BE SOME ISOLATED LAKE EFFECT SNOW SHOWERS ALONG THE SOUTH
SHORE AS 8H TEMPS OF -8C TO -10C BLOW ACROSS A +5C LAKE SUPERIOR.
HOWEVER...A WEST COMPONENT DOES NOT GIVE A VERY LONG FETCH AND IF
ANY SNOW SHOWERS DO OCCUR...THEY WILL BE ISOLATED AND LIGHT.
BROAD UPPER LEVEL TROFINESS WILL DOMINATE THE FLOW THROUGH THE
EXTENDED PERIOD. THIS WILL KEEP THE NORTHLAND IN A MILD SOUTHWEST OR
WEST AIRFLOW. ONCE THE CURRENT LOW PRESSURE PASSES THERE WILL BE
LITTLE PRECIPITATION UNTIL ABOUT SATURDAY WHEN ANOTHER LOW WILL MOVE
NORTH INTO IOWA AND ILLINOIS. AND ANOTHER ONE MAY BRING SNOW NEXT
TUESDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1144 PM CST TUE DEC 22 2015
A MIX OF MVFR/VFR AT THE BEGINNING OF THE FORECAST AS DRIER AIR
HAS ERODED SOME OF THE LOWER CIGS. NEXT ROUND OF PCPN WILL AFFECT
PRIMARILY DLH AND HYR ABOUT 15Z. WITH THE WARM TEMPS IN
PLACE...EXPECT LIGHT RAIN. THIS WILL CONTINUE UNTIL 00Z WHEN
COLDER AIR BEGINS TO CHANGE THE RAIN OVER TO SNOW. CIGS WILL DROP
BACK INTO THE IFR/LOW END MVFR RANGE WITH THE PCPN.
ELSEWHERE...THE MVFR CIGS PREVAIL WITH SOME FLURRIES AFTER 21Z.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 30 34 22 25 / 30 70 30 10
INL 30 33 18 22 / 10 20 30 20
BRD 30 33 19 24 / 10 20 20 10
HYR 32 36 24 28 / 70 100 50 10
ASX 32 37 27 30 / 50 90 60 20
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
LS...SMALL CRAFT ADVISORY UNTIL 6 AM CST WEDNESDAY FOR LSZ140-141.
&&
$$
UPDATE...GSF
SHORT TERM...HUYCK
LONG TERM...CLC
AVIATION...GSF
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
350 AM CST WED DEC 23 2015
.SHORT TERM: (Through Tonight)
Issued at 344 AM CST Wed Dec 23 2015
Showers and thunderstorms will be on the increase this morning as
surface low and associated upper level trof continue to lift north
northeast from TX panhandle towards the western Great Lakes region
by early this evening. Forecast area to remain on warm side of
system through midday before strong cold front slides through
region. Main question is will this initial round of activity muddy
the waters for any severe convection with frontal boundary this
afternoon. Think there will be enough of break in precipitation and
clouds to see atmosphere become unstable with CAPES between 500 and
1200 J/kg as strong low level jet advects dewpts in the upper 50s to
low 60s into the region by this afternoon. Forecast soundings
continue to indicate deep layer shear, curved hodographs and this
combined with decent instability, supercell development is expected
with the main threats being tornadoes and damaging winds, though
some large hail is possible as well. The best area to see this would
be southeast MO and southwestern IL. However, latest HRRR run is
indicating some supercell development further north closer to
deepening surface low over northeast MO and west central IL. Will
have to keep an eye out on these changing conditions.
Otherwise, will see temperatures rising through midday on gusty
south winds, into the 60s, then remain steady or slowly fall as
frontal boundary slides through. Could see gusts between 35 and 40
mph at times outside of storms. Storms to taper off by early this
evening with winds veering to the west on back side of system and
diminishing.
Byrd
.LONG TERM: (Thursday through Tuesday)
Issued at 344 AM CST Wed Dec 23 2015
(Thursday through Christmas Day)
Dry weather expected for most of the area through Christmas Day with
temperatures remaining above normal, in the upper 40s to low 60s.
With stalled frontal boundary just south of forecast area, could see
some light rain for far southern portions of forecast area Christmas
Day.
(Christmas Night through Tuesday)
Frontal boundary that is stalled south of the forecast area will
move back northward Christmas night and Saturday. Will see numerous
rounds of showers and embedded thunderstorms across the region
through Monday before tapering off Monday night as associated
surface low lifts northeastward through region and into the Great
Lakes region by Monday night. At this time, models are indicating
between 3 and 6 inches of rain with locally higher amounts possible.
The axis of heaviest rain will extend from southwestern MO
through the St. Louis metro area and into central Illinois. This
will affect area rivers and streams, leading to additional
flooding. For more details, please see the hydrologic outlook
(ESF).
Byrd
&&
.AVIATION: (For the 06z TAFs through 06z Wednesday Night)
Issued at 1142 PM CST Tue Dec 22 2015
Predominantly IFR CIGs should continue to push NW overnight and
expand to affect the remainder of the TAF sites. IFR VSBYs have
advanced to the edge of STL metro and CPS, but seem to have slowed
down as of late and still debatable whether they will expand into
STL, SUS, and UIN. With this issuance have added to STL TAF but
left out of the others. These clouds will prevail until low level
steering winds develop a westerly component to them Wednesday
morning and should see improvement to them into MVFR.
A low level jet of 45-50kts is currently over the area and will
continue into Wednesday morning. With the strong inversion in
place, maintained the LLWS mention.
Showers and a few TSRA will rapidly expand into the area towards
daybreak. Added VCTS to all sites with increasing signals and
probs for thunder. This should last for 3-4 hours.
A new round of SHRA/TSRA will try to develop later in the
afternoon Wednesday but relatively high uncertainty remains on
coverage which looks sparse on the latest models. Have added VCTS
for now with a small temporal window of 2 hours.
TES
&&
.PRELIMINARY POINT TEMPS/POPS:
Saint Louis 68 43 56 38 / 90 30 5 10
Quincy 64 37 47 33 / 90 30 10 5
Columbia 67 38 53 35 / 90 10 5 5
Jefferson City 69 38 55 36 / 90 10 5 10
Salem 67 45 57 40 / 100 60 5 10
Farmington 67 42 59 39 / 90 20 5 10
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1142 PM CST TUE DEC 22 2015
.UPDATE:
Issued at 927 PM CST Tue Dec 22 2015
A few adjustments to the forecast tonight...mainly to try and time
clouds a little better and to reflect precip trends shown by the
latest short range guidance. Both the RAP and HRRR are delaying
the onset of precipitation until after 10-11Z across much of the
area, so have cut back the PoPs a bit...keeping likelies out of
the forecast until 11-12Z, and then only in far southern zones and
northwest zones where guidance is showing accumulating precip.
Quickly ramp up to likely and categorical after 12Z.
Of second concern, watching fog inch toward our southeast CWFA
border. Will continue to monitor, but I may have to issue a dense
fog advisory before midnight if the fog continues to spread
northeast.
Carney
&&
.SHORT TERM: (Through Late Tonight)
Issued at 332 PM CST Tue Dec 22 2015
Over the last few hour the low stratus has eroded rapidly in most of
the MO counties in our CWA. However, some lower clouds are
lingering over our s IL counties, with another, more persistent and
thicker cloud deck remaining anchored in the post frontal AMS from
se MO into the Ohio Valley. With a s/se component to the low level
flow continuing overnight believe that lower clouds will expand
across the eastern half of the CWA during the evening through a
combination of redevelopment with noctural cooling of the boundary
layer and/or nwd advection of Ohio Valley cloud deck. Over central
MO, the higher level cloudiness of this evening should also give way
to lower clouds after midnight as increasing southerly flow/low
level jet causes low level moisture to surge into the area.
The resultant moisture transport and isentropic ascent, combined
with larger scale UVV associated with lead shortwave ejecting ahead
of central Plains trof, should allow showers to develop after 06z in
a N/S band west of the Mississippi River that will gradually
increase in coverage and expand east with time. Although forecast
instability looks fairly meager the low level advection profile does
lead to decent lower/mid level lapse rates that would support the
idea of some elevated convection. For now I`ve maintained slight
chance of thunderstorms because of this, but evening shift will
certainly have to monitor this.
Temperatures may dip briefly this evening, before the combo of
increasing winds and clouds cause steady or slowly rising temps
during the overnight hours.
Truett
.LONG TERM: (Wednesday through Next Tuesday)
Issued at 332 PM CST Tue Dec 22 2015
(Wednesday)
Very active and unsettled weather on Wednesday as sfc low deepends
across eastern Kansas early Wednesday morning and tracks toward
southern Iowa by midday. Expect north/south oriented band of rain
showers w/ embedded thunderstorms to sweep through the area. Should
be a break during the late morning hours/early afternoon before at
least scattered thunderstorms develop along the trailing cold front.
Threat of severe thunderstorms has increased over the past 24-48
hours due to higher forecast instability. NWP guidance suggests
SBCAPE values of 500-1000+ J/kg as a break in the rainfall and
possible breaks in the clouds would help to increase the
instability...potentially even further than what is currently being
advertised. Deep-layer shear of 50-70 knots combined with the
forecast instability would be more than enough to support all forms
of severe weather. Supercells are also quite possible along/ahead of
front as deep-layer shear vector is oriented roughly 30 degrees to
cold front. Tornado threat is increased due to very high 0-1km shear
and helicity...but south/southwest sfc winds and relatively high
LCL values could be inhibiting factors to tornadic development.
(Thursday through Christmas Day)
A relatively quiet quiet period will come between Thursday and
Christmas Day. Mostly dry weaher is expected with the exception
being Christmas Day acrosss the southeastern portion of the CWA with
a chance of showers as warm advection increases at lower levels.
Temperatures both day/night will be cooler than Wednesday...but
still well above normal levels for the end of December.
(Christmas Night through Monday)
Frontal boundary that had stalled south of the CWA will move back
northward Christmas night and Saturday and bring a round of showers
and embedded thunderstorms to the region. The retreating warm front
is then forecast to stall out somewhere across the CWA and provide
the focus for widespread showers/thunderstorms through Saturday
night with moderate to potentially heavy rainfall rates. Frontal
boundary will sag back southward by Sunday morning. Temperatures
will cool and instability...even aloft...becomes negligible. Have
removed thunder wording for the Sunday period but still have
likely/categorical PoPs north of the boundary for light/moderate
rain. Sunday looks like a real chilly/raw day with high temperatures
foercast to be only in the 40s with northeast winds and rain. Sfc
system will occlude near the Arklatex region late on Sunday and
track toward north-central Missouri by Monday afternoon. Another
round of moderate to potentially heavy rainfall is likely to occur
late Sunday night/early Monday along with embedded thunderstorms
also possible. An early look at total rainfall for this event looks
to be on the order of 3 to 6 inches across the southeastern half of
the CWA...with locally higher amounts possible due to convection.
This rainfall will likely lead to additional flooding along area
rivers/streams. For more details...please see the hydrologic outlook
(ESF).
(Tuesday)
The atmosphere looks to finally quiet down next Tuesday as the
previous system moves out into southeastern Canada. Temepratures
will remain above normal on Tuesday with highs in the 40s. Some
signs of a pattern shift heading toward the New Year as longwave
ridging builds near the west coast. If this indeed occurs...at
turn toward near or below normal temperatures and drier conditions
would be more likely.
Gosselin
&&
.AVIATION: (For the 06z TAFs through 06z Wednesday Night)
Issued at 1142 PM CST Tue Dec 22 2015
Predominantly IFR CIGs should continue to push NW overnight and
expand to affect the remainder of the TAF sites. IFR VSBYs have
advanced to the edge of STL metro and CPS, but seem to have slowed
down as of late and still debatable whether they will expand into
STL, SUS, and UIN. With this issuance have added to STL TAF but
left out of the others. These clouds will prevail until low level
steering winds develop a westerly component to them Wednesday
morning and should see improvement to them into MVFR.
A low level jet of 45-50kts is currently over the area and will
continue into Wednesday morning. With the strong inversion in
place, maintained the LLWS mention.
Showers and a few TSRA will rapidly expand into the area towards
daybreak. Added VCTS to all sites with increasing signals and
probs for thunder. This should last for 3-4 hours.
A new round of SHRA/TSRA will try to develop later in the
afternoon Wednesday but relatively high uncertainty remains on
coverage which looks sparse on the latest models. Have added VCTS
for now with a small temporal window of 2 hours.
TES
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
National Weather Service Kansas City/Pleasant Hill MO
1137 PM CST TUE DEC 22 2015
.UPDATE...
Issued at 935 PM CST TUE DEC 22 2015
Have made some adjustments to the overnight as well as Wednesday`s
PoPs. This will be most noticeable over the west central and northern
CWA. Satellite imagery shows a shortwave trough lifting northeast
from the eastern TX Panhandle/northwest TX area with a vorticity max
near CDS. Expect scattered elevated showers to form ahead of this
feature after 06z once a narrow tongue of h8 moisture is lifted into
the region via isentropic ascent on the 295K surface. Have followed
the HRRR trend of the past 3-4 runs which is supported quite well by
the 00z NAM as well as the 18z runs of the NAM and GFS. Think we`ll
see showers break out across northwest MO first with a southward
development into the KC area. Will probably see some scattered
elevated showers also pop up well downstream across northeast MO.
Using the above models as a guide believe the deeper moisture
represented by the h7 condensation pressure deficits will be swept
northeast rather quickly and by 15zish Wednesday the more widespread
showers will have lifted out of west central and north central MO.
The deformation band of more stratiform rain now looks like it will
linger over northwest MO well into the afternoon hours.
Have also adjusted overnight temperatures to reflect a steady as she
goes to a slight upward drift.....at least until the rain forms.
&&
.DISCUSSION...
Issued at 345 PM CST TUE DEC 22 2015
Big picture today shows the Nation dominated by a large trough who`s
axis resides across the Western Plains. The local result is a
southwest flow across the Lower Missouri River Valley which has
helped keep the cooler winter air out of our section of the Central
Plains. So, despite that fact that it was cloudy and cold this
morning, along with it being late December, we have warmed into the
40s and 50s again across the region with the help of the southeast
surface wind. Tonight, a shortwave trough, swinging through the base
of the mean longwave trough, will lift across the Central and
Northern Plains late tonight and Wednesday. Resulting warm air
advection ahead of the shortwave will kick in late tonight and
persist through much of Wednesday morning. Currently, models
advertise the rain to move to our northeast by noon Wednesday, but
showers and isolated thunderstorms may linger into the afternoon,
especially as you look farther east across Missouri. None of tonight
or Wednesday weather is expected to be severe, and rainfall totals
Wednesday are only expected to be around a few tenths at most.
For Thursday into Christmas Day...locally, across far eastern Kansas
and the northern half of Missouri, we expect it to be dry, but there
is a none-zero chance that a little precipitation might occur.
Thursday a secondary shortwave trough will follow the larger
Wednesday shortwave trough northeast across the Plains. Most models
have been keen to focus on this quick secondary shortwaves potential
to squeeze some light precipitation out. Have kept slight chance
POPs in across far northern reaches of the forecast area through
Wednesday night into Thursday; and depending on temperatures at that
time, some snow might develop. And, for Christmas Day, while it
could be overcast day, currently it looks like the daylight hours
will be dry locally, but we will be watching for rain to spread
north from southern Missouri that night, with rain persisting
through the weekend.
The weather Christmas Night, and through the weekend, is going to be
a bit of mess. Thursday and Friday we don`t have much chance of
getting wet as we are between storm inducing shortwave troughs, but
by Friday a large amplification in the flow is expected as a strong
shortwave trough digs deep into the mean CONUS trough across the
western CONUS, eventually developing a closed low over the Desert
Southwest which will slowly amble northeast across the Plains late
this weekend into next work week. ECMWF and GFS solutions have all
been pointing at this, though specifics on where the low goes and
how quickly it gets there have been all over the place, with the
ECMWF slowing and then speeding the low up significantly over the
past two model runs. For early in the event, Christmas Night into
Saturday, we will be well ahead of the closed low which will help
keep our temperatures benign for late December with high in the 40s
and 50s still possible Saturday. This means any precipitation early
on will be all liquid for our area. And, the amount of QPF the
models are spitting out indicates that a lot of rain will fall.
Currently, storm totals from Friday night through Monday night in
central Missouri are in the 4 to 6 inch range, tapering to between 1
and 2 inches in the far northwest corner of Missouri. As a result,
anticipate river and stream flooding will be an issue over the
weekend and into next week.
Otherwise, there will be an issue with precipitation type late in
the weekend and early next work week as the low ejects northeast
across the Plains. However, this far out in time, models are having
the typically hard time settling on a solution with the medium
range operational and ensemble models showing a fair amount of
spread in the solutions. So, with out any cold air in place across
our section of the country confidence in precipitation types late in
the weekend and next work week are very low, but have included some
snow and rain snow mix in parts of the Sunday through Monday night
periods.
&&
.AVIATION...(For the 06Z TAFS through 06Z Wednesday Night)
Issued at 1130 PM CST TUE DEC 22 2015
Radar imagery is currently depicting light echoes over eastern
Kansas, though initially, precipitation surrounding the terminal
sites will need to overcome dry air below 15 kft. Once conditions
become saturated, some light rain showers and maybe a clap or two of
thunder will affect the area in the early overnight hours. Ceiling
heights will reduce to MVFR at this time as low level moisture makes
its way into the area from the south. This activity should taper off
early Wednesday morning as mid-level winds shift to the southwest,
however, IFR ceilings will then form as temperatures cool and low-
level moisture remains over the area. Conditions will improve in the
afternoon as winds increase out of the northwest, gusting to 25-30
mph at times. VFR conditions should finish out the remainder of the
period as the surface low pushes off to the northeast.
&&
.EAX Watches/Warnings/Advisories...
KS...NONE.
MO...NONE.
&&
$$
UPDATE...MJ
DISCUSSION...Cutter
AVIATION...Welsh
AREA FORECAST DISCUSSION
NWS HASTINGS NE
400 AM CST WED DEC 23 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 332 AM CST WED DEC 23 2015
RADAR HAS AREAS OF LIGHT RAIN MOVING THROUGH THE EASTERN PART OF THE
FORECAST AREA EARLY THIS MORNING. TEMPERATURES IN THE AREA OF RAIN
ARE WARM ENOUGH AT THIS TIME TO CONTINUE TO BE RAIN. TO THE WEST OF
THE RAIN THE TEMPERATURES HAVE STARTED TO COOL OFF.
THROUGH DAYBREAK AND INTO THE MORNING HOURS AN UPPER LEVEL LOW IS
MOVING THROUGH THE AREA. EVEN THOUGH IT IS IN THE FIRST FEW HOURS OF
THE FORECAST...THERE ARE A FEW DIFFERENCES. THE HRRR AND RAP KEEP
PRECIPITATION ONLY IN THE FAR EAST WHILE THE 4KM WRF...NAM AND GFS
PUSH THE PRECIPITATION FURTHER TO THE EAST. THE BEST CHANCE WILL
DEFINITELY BE IN THE EAST...BUT HAVE KEPT SOME LOWER POPS FURTHER TO
THE WEST. THIS BRINGS IN A PROBLEM FOR PRECIPITATION TYPE. WHILE THE
TEMPERATURES ALOFT ARE WARM ENOUGH FOR RAIN...SO IS THE SURFACE.
ONCE THE TEMPERATURES ALOFT COOL OFF THE SURFACE DOES AS
WELL...MAKING A CHANGE TO SNOW. HAVE KEPT A RAIN AND SNOW MIX IN THE
WEST/NORTHWEST THROUGH DAY BREAK AND INTO THE MORNING HOURS AS THE
PRECIPITATION IS MOVING OUT OF THE AREA. BY MID DAY THE UPPER LOW
HAS MOVED EAST AND EXPECT THAT PRECIPITATION SHOULD COME TO AN END.
THERE WILL ALSO BE SOME CLEARING AND A LITTLE SUNSHINE FOR A TIME
THIS AFTERNOON.
THE NEXT UPPER LEVEL WAVE WILL BE MOVING INTO THE AREA TONIGHT.
EXPECT PRECIPITATION TO MOVE INTO THE AREA FROM THE SOUTHWEST
TONIGHT. TEMPERATURES ARE EXPECTED TO BE COLD ENOUGH THAT EXPECT
SNOW ACROSS THE ENTIRE AREA. THE BEST CHANCE FOR ACCUMULATING SNOW
WILL BE MAINLY LATE TONIGHT. THROUGH MORNING...EXPECT THERE TO BE
LESS THAN AN INCH OR LESS OF SNOW.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 347 AM CST WED DEC 23 2015
THE MID AND LONG TERM FORECASTS CONTINUE TO BE INTERESTING AND
CHALLENGING.
CHRISTMAS EVE - CHRISTMAS NIGHT:
THERE MAY BE SOME LINGERING SNOW ACROSS THE AREA EARLY THURSDAY
MORNING...BUT EXPECT IT TO MOVE OFF OVER EASTERN NEBRASKA BY MID
MORNING. SKIES ARE EXPECTED TO CLEAR AND HIGHS...IF NOT IMPACTED
MUCH BY ANY SNOW ACCUMULATION OVERNIGHT WILL REACH INTO THE 30S TO
LOW 40S.
ON CHRISTMAS DAY A PIECE OF THE MAIN DISTURBANCE THAT WILL IMPACT
THE REGION FOR THE WEEKEND INTO EARLY NEXT WEEK WILL BREAK OFF AND
MOVE NORTHEAST ACROSS THE AREA. THIS WILL BRING THE POSSIBILITY
FOR PRECIPITATION MAINLY ACROSS NORTHERN NEBRASKA...BUT SOME COULD
CREEP INTO CENTRAL NEBRASKA DURING THE LATE AFTERNOON AND
OVERNIGHT. HIGHS WILL BE SIMILAR TO THURSDAY.
SATURDAY - TUESDAY:
THIS PERIOD IS THE MOST CHALLENGING. THE GUIDANCE HAS EVOLVED FROM
LAST NIGHT`S...GIVING A SLOWER SOLUTION...TRENDING TOWARDS LAST
NIGHTS ECMWF. THE SLOWER/FURTHER SOUTH ROUTE IS IMPACTING THE
AREA OF PRECIPITATION POTENTIAL. CONFIDENCE ON THIS PART OF THE
FORECAST IS RELATIVELY LOW. CONFIDENCE IS HIGH THAT A SYSTEM WILL
IMPACT THE CENTRAL AND SOUTHERN PLAINS...BUT THE DETAILS OF WHEN
AND WHERE ARE STILL VERY UNCLEAR.
WHILE LAST NIGHT`S FORECAST HAD SATURDAY NIGHT THROUGH SUNDAY IN
THE PERIOD WITH THE BEST CHANCES FOR ACCUMULATING SNOW...THIS HAS
CHANGED...WITH SUNDAY NIGHT INTO TUESDAY WITH THE LARGER CONCERN.
THIS IS NOT OVERLY UNEXPECTED WITH THE SLOWER SOLUTION. SO AS TO
NOT FLIP FLOP ON THE FORECAST HAVE KEPT PRECIPITATION CHANCES FOR
SATURDAY AND SUNDAY...BUT WITH THE CURRENT GUIDANCE...CHANCES ARE
MUCH LESS. A COLD FRONT WILL MOVE THROUGH VERY EARLY SATURDAY
MORNING WHICH WILL DROP TEMPERATURES WITH BREEZY NORTH WINDS. THIS
WILL CAUSE HIGHS FOR THE REMAINDER OF THE FORECAST TO BE IN THE
20S.
THE GFS DID SLOW TO CONVERGE ON A SOLUTION SIMILAR TO THE
ECMWF...BUT IT STILL EJECTS THE DISTURBANCE NORTHEASTWARD QUICKER
ON MONDAY MORNING. WHEREAS THE ECMWF PULLS THE UPPER LOW AND
ASSOCIATED SURFACE LOW ACROSS THE AREA MONDAY NIGHT INTO TUESDAY.
THE SLOWER SOLUTION ALLOWS THE TEMPERATURES TO REMAIN COLD ENOUGH
THROUGHOUT THE COLUMN FOR SNOW TO BE THE MAIN PRECIPITATION TYPE
AFTER THE TRANSITION WITH THE COLD FRONT ON SATURDAY THROUGH THE
REMAINDER OF THE WEEKEND INTO EARLY NEXT WEEK.
DUE TO THE LOW CONFIDENCE WITH MODEL DISCREPANCIES...STILL THINK
SOME TRAVEL THROUGH THE CENTRAL AND SOUTHERN PLAINS WILL BE
HAZARDOUS FOR PORTIONS OF THE HOLIDAY WEEKEND. IT IS STILL TOO
EARLY TO SPECULATE ON SNOW ACCUMULATIONS...ESPECIALLY WITH THE
MODEL CHANGES...BUT SNOW ACCUMULATION IS POSSIBLE THIS WEEKEND
INTO THE BEGINNING OF THE WEEK. STAY TUNED TO THE FORECASTS AS IT
CONTINUES TO EVOLVE AND THE DETAILS ARE REFINED.
&&
.AVIATION...(FOR THE 06Z KGRI/KEAR TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1119 PM CST TUE DEC 22 2015
A SURFACE TROUGH HAS MOVED THROUGH THE TERMINALS. THERE IS AN
UPPER LEVEL WAVE THAT MOVES THROUGH AROUND DAY BREAK. EXPECT THERE
TO BE SOME PRECIPITATION AROUND THE AREA AS THE UPPER LEVEL WAVE
MOVES THROUGH. THE PRECIPITATION WILL MOVE OUT WITH A BREAK
THROUGH MUCH OF THE REMAINDER OF THE PERIOD. TOWARD THE VERY END
THERE IS ANOTHER CHANCE FOR SOME PRECIPITATION.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...JCB
LONG TERM...BILLINGS WRIGHT
AVIATION...JCB
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
1002 PM PST TUE DEC 22 2015
.SYNOPSIS...A MOIST NORTHWEST FLOW WILL BRING OCCASIONAL CLOUDS AND
GUSTY WINDS TO THE REGION THROUGH WEDNESDAY. ANOTHER SYSTEM WILL
APPROACH THE AREA ON CHRISTMAS EVE DAY THEN PASS THROUGH AT NIGHT
WITH ANOTHER ROUND OF GUSTY WINDS AND SHOWERS POSSIBLE. CHILLY BUT
DRY WEATHER IS EXPECTED FROM CHRISTMAS DAY THROUGH THE WEEKEND.
&&
.UPDATE...ANOTHER ROUND OF FUN AND GAMES WITH THE WIND THIS EVENING
AS NORTH TO NORTHWEST WINDS HOWLED DOWN THE OWENS VALLEY AND
ADJACENT EASTERN SIERRA SLOPES THIS AFTERNOON AND THEN ACROSS
NORTHWEST SAN BERNARDINO COUNTY THIS EVENING. THE HRRR AND SOME HIGH-
RESOLUTION MODELS HAVE NOT HANDLED THIS WELL AT ALL AND THUS THE GFS
LAMP SEEMS TO BE MORE ON TARGET WITH WITH SPEEDS WHICH LOOK TO STAY
UP ENOUGH OVERNIGHT IN NORTHWEST SAN BERNARDINO COUNTY TO JUSTIFY AN
ADVISORY. AS A RESULT, I ISSUED ONE AND RAN IT THROUGH 10 AM
WEDNESDAY SINCE WINDS HAVE NOT BEEN COOPERATING THE BEST AND MAY BE
RELUCTANT TO DIMINISH.
THE NEXT ISSUE TONIGHT IS WAY IN THE EASTERN PART OF OUR AREA AS
SURFACE DEWPOINTS HAVE HELD UP AGAINST GUIDANCE AND HIGHER LEVEL
CLOUDS HAVE CLEARED ON OUT BY SURFACE OBSERVATIONS SHOW BKN-OVC
REPORTS STILL. I ADJUSTED UP SKY COVER AFTER LOOKING AT FORECAST
SOUNDINGS WHICH KEEP THE LOW-LEVELS IN THE PLATEAU COUNTRY OF MOHAVE
COUNTY NEARLY SATURATED OVERNIGHT AND INTO EARLY WEDNESDAY MORNING.
I ALSO ADDED PATCHY FOG TO THE GRIDS AS WHATEVER STRATUS DECK IS
THERE MAY DROP DOWN TO THE SURFACE LATER TONIGHT. IN AREAS WHERE
TEMPS FALL TO OR BELOW FREEZING BLACK ICE IS POSSIBLE ON ROADS. THE
MOST AT RISK AREAS WILL BE ON INTERSTATE 40 AND ROUTE 66 EAST OF
KINGMAN AS WELL AS IN AND AROUND COLORADO CITY. THERE IS ALSO SOME
POTENTIAL FOR FOG IN AND AROUND LAS VEGAS OVERNIGHT, BUT CONFIDENCE
IS LOWER IN THIS.
LASTLY, LIGHT SNOW HAS BEEN REPORTED AT ELY IN THE LAST HOUR AND
ALTHOUGH POPS WERE ADJUSTED IN SOME SPOTS TO BAG PRECIP, THIS SHOWER
ACTIVITY COULD STILL ROLL INTO NORTHERN LINCOLN COUNTY LATER ON.
&&
.AVIATION...FOR MCCARRAN...WESTERLY WINDS TO SOUTHWEST AT TIMES AT 4-
8 KTS OVERNIGHT. WINDS ARE FORECAST TO BE NORTH TO NORTHEAST
WEDNESDAY WITH SPEEDS BETWEEN 6-8 KTS BEFORE TURNING TO THE
SOUTHWEST TO WEST AROUND 03Z THURSDAY. THERE IS ENOUGH LOW-LEVEL
MOISTURE THAT AREAS OF FOG OR LOWER CLOUDS MAY DEVELOP IN AND AROUND
THE LAS VEGAS VALLEY LATE TONIGHT INTO WEDNESDAY MORNING. HOWEVER,
CONFIDENCE IS LOW IN THIS. THE BEST WINDOW WOULD BE BETWEEN 10Z AND
17Z WEDNESDAY. OTHERWISE, LOOK FOR MAINLY SCT CLOUDS AOA 7K FEET.
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...WESTERLY WINDS GUSTING TO 30-40 KTS OVERNIGHT THROUGH
18Z WEDNESDAY IN NW SAN BERNARDINO COUNTY WITH POSSIBLE PATCHY BLDU.
OTHERWISE MAINLY DIURNAL WINDS UNDER 10 KTS OVERNIGHT AND AGAIN ON
WEDNESDAY EXCEPT IN THE SOUTHERN GREAT BASIN WHERE NORTHWEST TO
NORTH WINDS OF 6-12 KTS WITH GUSTS TO 20 KTS ARE POSSIBLE. AREAS OF
FOG AND LOW CLOUDS WITH BASES DOWN TO AT LEAST 500 FEET ARE POSSIBLE
LATE TONIGHT MAINLY NORTH AND EAST OF KIGM INCLUDING IN AND AROUND
KAZC. THERE IS ALSO SOME POTENTIAL AS WELL IN PARTS OF SOUTHERN
NEVADA. THE MAIN WINDOW WOULD BE BETWEEN 10Z AND 17Z WEDNESDAY.
OTHERWISE, MAINLY SCT-BKN CLOUDS AT TIMES AOA 7K FEET. ISOLATED
SHOWERS ARE POSSIBLE OVERNIGHT AND EARLY WEDNESDAY IN FAR NORTHERN
LINCOLN COUNTY AND IN AND AROUND KAZC.
&&
.SHORT TERM...THROUGH WEDNESDAY NIGHT.
NORTHWEST FLOW WILL CONTINUE OVER THE REGION THROUGH WEDNESDAY WITH
OCCASIONAL CLOUDS AND A FEW SHOWERS POSSIBLE OVER THE FAR NORTHERN
AND EASTERN PORTIONS OF THE FORECAST AREA. WINDS ARE EXPECTED TO BE
LIGHTER WEDNESDAY ALONG WITH SOME LIGHT ISOLATED SHOWERS MAINLY OVER
THE HIGHER ELEVATIONS. TEMPERATURES WILL REMAIN CLOSE TO NORMAL.
.LONG TERM...THURSDAY THROUGH MONDAY.
NEXT STORM SYSTEM TO AFFECT THE REGION WILL MOVE IN THURSDAY IN THE
FORM OF YET ANOTHER FAST MOVING STORM SYSTEM FROM THE NORTHWEST.
MUCH LIKE THE LAST SEVERAL STORMS...THIS SYSTEM ONLY CLIPS US AND
MOVES FROM WEST TO EAST FAIRLY RAPIDLY LIMITING ANY POTENTIAL
IMPACTS. NONETHELESS...WIND AND SOME WINTER WEATHER IMPACTS CAN
STILL BE EXPECTED ESPECIALLY GIVEN THE SENSITIVE NATURE OF THE
HOLIDAY TRAVEL PERIOD.
WINDS WILL BEGIN PICKING UP ALONG A BELT STRETCHING FROM THE WESTERN
MOJAVE DESERT EAST INTO NORTHWEST ARIZONA ON THURSDAY AND ITS LIKELY
SOME WIND PRODUCTS WILL BE NEEDED DOWN THE LINE TO ACCOUNT FOR THIS.
AS THE TROUGH QUICKLY PROGRESSES FROM NORTHERN CALIFORNIA ACROSS THE
GREAT BASIN IT WILL DRAG A FAIRLY STRONG COLD FRONT SOUTHWARD WITH
IT. WHILE RAIN AND SNOWFALL WILL BE FAIRLY LIGHT WITH THIS QUICK
MOVING FRONT...PARTS OF LINCOLN COUNTY AND NORTHERN MOHAVE COUNTY
STAND THE CHANCE TO PICK UP A QUICK FEW INCHES OF SNOW...AND THESE
AREAS VERY WELL MAY WAKE UP TO A WHITE CHRISTMAS. WE WILL NEED TO
CONSIDER THE NEED FOR A WINTER WEATHER ADVISORY AS THE EVENT DRAWS
CLOSER DUE TO THE SENSITIVE NATURE OF HOLIDAY TRAVEL ON CHRISTMAS
EVE AND CHRISTMAS DAY. ELSEWHERE...ONLY LIGHT AMOUNTS OF RAIN OR
SNOW ARE EXPECTED WITH VERY LITTLE OR NO SNOW ACCUMULATION.
THINGS WILL QUICKLY DRY OUT ON CHRISTMAS DAY WITH STRONG NORTH WINDS
BECOMING THE GREATER CONCERN. NORTH WINDS WILL CONTINUE TO
STRENGTHEN INTO SATURDAY AS THE LOW CUTS OFF AND DIGS SOUTH INTO
ARIZONA...INDUCING A STRONG NORTH FLOW INTO OUR REGION. WINDS MAY
END UP BECOMING QUITE STRONG ESPECIALLY IN FAVORABLE LOCATIONS FOR
NORTH WINDS...SUCH AS DOWN THE LOWER COLORADO RIVER NEAR NEEDLES AND
LAUGHLIN. HIGH WIND PRODUCTS ARE A DEFINITE POSSIBILITY FRIDAY
NIGHT-SATURDAY AND IT WOULD BE ADVISABLE AT THIS POINT TO RECONSIDER
OUTDOOR RECREATION PLANNED SATURDAY ON THE AREA LAKES.
OUTSIDE OF WIND AND WEATHER...TEMPERATURES WILL BE SHARPLY COOLER
FRIDAY ONWARD AS THE COLD FRONT PUSHES EAST AND STRONG NORTH FLOW
LINGERS OVER THE AREA. TEMPERATURES IN LAS VEGAS ARE LIKELY TO
REMAIN BELOW 50 FOR A PERIOD OF SEVERAL DAYS WITH SUBFREEZING
TEMPERATURES POSSIBLE AT NIGHT DEPENDING ON THE WINDS. THE ENTIRE
REGION WILL BE AVERAGING 8 TO 12 DEGREES BELOW SEASONAL NORMALS FOR
HIGH TEMPERATURES. THE HOLIDAY SEASON IS HERE...AND IT WILL SURE
FEEL LIKE IT!
&&
.SPOTTER INFORMATION STATEMENT...SPOTTERS ARE ENCOURAGED TO REPORT
ANY SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING
PROCEDURES.
&&
$$
UPDATE/AVIATION...STACHELSKI
SHORT TERM...GORELOW
LONG TERM...OUTLER
FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE:
HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER
AREA FORECAST DISCUSSION
NWS RALEIGH NC
415 AM EST WED DEC 23 2015
.SYNOPSIS...A WEDGE FRONT WILL REMAIN QUASI-STATIONARY OVER THE
PIEDMONT EARLY TODAY...THEN BE OVERTAKEN BY A MARITIME WARM FRONT
THAT WILL SURGE ACROSS THE CAROLINAS AND SOUTHEASTERN VIRGINIA THIS
AFTERNOON. ANOMALOUSLY STRONG SUB-TROPICAL HIGH PRESSURE OVER THE
WEST-CENTRAL ATLANTIC OCEAN WILL THEN DIRECT UNSEASONABLY WARM AND
MOIST SOUTHERLY FLOW THROUGHOUT THE SOUTHEASTERN UNITED STATES
THROUGH CHRISTMAS.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 355 AM WEDNESDAY...
...FLASH FLOOD WATCH CONTINUES ACROSS THE WESTERN PIEDMONT...
A SHORTWAVE TROUGH EMBEDDED WITHIN LARGER-SCALE TROUGH SITUATED
ACROSS MUCH OF THE CONUS WILL ADVANCE NEWD FROM THE SRN PLAINS
TOWARDS THE UPPER GREAT LAKES. ACCOMPANYING DEEPENING SFC LOW WILL
FOLLOW SUITE...TRACKING NEWD FROM THE MID-MO VALLEY TO THE UPPER MS
VALLEY BY LATE AFTERNOON. WHILE THESE FEATURES ARE A LITTLE WAYS
FROM HOME...DEEP SOUTHERLY FLOW ON THE EAST SIDE OF THE TROUGH WILL
ADVECT MODIFIED GULF AIR NORTHWARD INTO THE AREA...BRINGING
ANOMALOUS MOIST AND WARM AIR INTO THE AREA. PWATS ARE FORECAST TO
INCREASE TO 1.6-1.9"(4-5 STANDARD DEVIATIONS ABOVE NORMAL)...WHICH
WILL RIVAL MAX DECEMBER VALUES AT KGSO(1.65"-DATING BACK TO
1948)...WHILE TONIGHTS LOW TEMPERATURES WILL STRUGGLE TO DROP OUT OF
THE 70S AT MOST LOCATIONS...AGAIN HAVING A GOOD CHANCE OF MATCHING
THE ALL-TIME WARMEST DECEMBER MINIMUM TEMPERATURE ON RECORD(RDU-
69...FAY-69...GSO-65).
TWO MAIN CONCERNS ARE: 1)PERIODS OF MODERATE TO HEAVY RAINFALL THAT
MAY RESULT IN BOTH FLASHING FLOODING AS WELL AS MINOR FLOODING
ON AREAS RIVERS AND CREEKS AND 2)ISOLATED THREAT OF SEVERE STORMS
LATER TODAY.
FLOOD THREAT: LATEST RADAR TRENDS SHOW AN UPTICK IN CONVECTION
BREAKING OUT ACROSS THE AREA...FUELED BY A STRENGTHENING 50-60KT S-
SW LOW-LEVEL FLOW TO THE EAST OF THE AMPLIFYING SYSTEM TO OUR WEST.
MOST RECENT HRRR SIMULATIONS ARE HANDLING THE CONVECTION
BEST...DEPICTING THE HEAVIEST RAINFALL THIS MORNING ALONG AND EAST
OF HIGHWAY 1. THE AFOREMENTIONED HIGH MOISTURE ANOMALIES WILL
SUPPORT THE POTENTIAL FOR 1.5-2.0"/HOUR RAINFALL RATES OVER THESE
AREAS THIS MORNING THAT WOULD LIKELY CAUSE SOME LOCALIZED FLOODING
GIVEN SATURATED SOILS. HAVE ENTERTAINED THE IDEA OF EXPANDING THE
FLOOD WATCH TO INCLUDE COUNTIES ACROSS THE SANDHILLS AND CENTRAL
PIEDMONT...BUT AS PRECIP HAS BECOME MORE CONVECTIVE IN NATURE...ANY
SUCH HEAVY PRECIP WOULD BE FAIRLY LOCALIZED. WITH A SECOND ROUND OF
SHOWERS AND POSSIBLY A FEW STRONG TO SEVERE STORMS EXPECTED LATER
THIS AFTERNOON AS WARM SECTOR BECOMES ESTABLISHED OVER THE
AREA...AREAS IN THE WATCH COULD STILL SEE LOCALIZED HEAVY AMOUNTS OF
ONE TO TWO INCHES. AS SUCH... WILL KEEP THE FLASH FLOOD WATCH
CONFINED TO THE WESTERN PIEDMONT.
SEVERE THREAT: AS TEMPS CLIMB INTO THE LOWER TO MID 70S AND SFC
DEWPOINTS APPROACH UPPER 60S TO NEAR 70...MODELS SHOW 500-1000 J/KG
OF MUCAPE(HIGHEST IN THE EAST)DEVELOPING OVER THE AREA. 40-50KT DEEP
SHEAR AND SHERBE VALUES APPROACHING 1.0 COULD SUPPORT A FEW STRONG
TO SVR WIND GUSTS AND POSSIBLY AN ISOLATED TORNADO. WILL CONTINUE TO
ADVERTISE SEVERE POTENTIAL ACROSS THE EASTERN HALF OF THE FORECAST
AREA IN THE HWO.
&&
.SHORT TERM /THURSDAY AND THURSDAY NIGHT/...
AS OF 355 AM WEDNESDAY...
ON THE WESTERN PERIPHERY OF ANOMALOUSLY STRONG SUB-TROPICAL RIDGING
CENTERED OVER THE WEST-CENTRAL ATLANTIC...SHORTWAVE RIDGING AND
ASSOCIATED HEIGHT RISES ALOFT WILL BUILD BEHIND THE MAIN SHORTWAVE
TROUGH LIFTING INTO EASTERN CANADA. WITH RIDGING ALOFT AND AN
ASSOCIATED PROBABLE CAPPING INVERSION DEPICTED ON NAM BUFR
SOUNDINGS...THE DAY WILL LIKELY BE A DRY ONE...THOUGH DIURNAL
HEATING OF THE UNSEASONABLY WARM (70S TO AROUND 80 IN IN THE I-95
CORRIDOR) AND HUMID BOUNDARY LAYER MAY ALLOW FOR SOME CU TO BYPASS
THE CAP AND GROW INTO ISOLATED SHOWERS/STORMS. IN ADDITION...AN
UPSTREAM QLCS...IN A REGION OF RESIDUALLY STRONG H85 MOISTURE
TRANSPORT DIRECTED INTO THE TN VALLEY...MAY SUPPORT THE EASTWARD
PROGRESSION OF A WEAKENING LONE OF SHOWERS AND STORMS TO CROSS THE
APPALACHIANS AND DRIFT INTO WESTERN NC...INCLUDING THE WESTERN
PIEDMONT EARLY THU NIGHT. INCREASING CINH WITH NOCTURNAL "COOLING"
INTO THE 60S FAVORS A DRY NIGHT OTHERWISE AND ELSEWHERE.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 410 AM WEDNESDAY...
THE STRONG SUB-TROPICAL RIDGE...WITH ANOMALOUSLY HIGH HEIGHTS AND
PRECIPITABLE WATER VALUES BETWEEN 200-300 PERCENT OF NORMAL FROM THE
SOUTHEASTERN UNITED STATES TO EAST-CENTRAL CANADA...WILL MAINTAIN A
VERY MILD-WARM REGIME ACROSS THE SOUTHEASTERN STATES THROUGHOUT THE
PERIOD...AND A WET ONE PRIMARILY NORTHWEST OF CENTRAL NC...AT LEAST
UNTIL LATE IN THE PERIOD. THE MAIN FORECAST UNCERTAINTY REMAINS THE
POSITIONING OF A WAVY FRONTAL ZONE FORECAST TO MEANDER ACROSS THE
MIDDLE ATLANTIC STATES...AND CONSEQUENTLY HOW MUCH SUPPRESSION OF
THE WARMTH OCCURS EAST OF THE APPALACHIANS...DICTATED BY A BATTLE
BETWEEN THE SUB-TROPICAL RIDGE AND CONFLUENT SPLIT FLOW
ALOFT/UNDERLYING POLAR HIGHS FORECAST TO DEVELOP ACROSS THE GREAT
LAKES AND NEW ENGLAND BY THIS WEEKEND.
THE TIMING OF POTENTIAL COLD FRONTAL SURGES INTO NC...IF THEY
OCCUR...ARE FAVORED LATE FRI NIGHT-SAT...AND AGAIN SUN NIGHT-
MON...WITH THE FORMER APPEARING INCREASINGLY UNLIKELY TO AFFECT
CENTRAL NC. OTHERWISE UNSEASONABLY MILD-WARM AND HUMID CONDITIONS IN
DEEP SOUTHERLY FLOW AROUND THE SUB-TROPICAL RIDGE WILL PREVAIL. THE
PRIMARY BRANCH OF THE NORTHERN STREAM WILL BE BLOCKED TO THE NW BY
THE SUB-TROPICAL RIDGING...SO FORCING FOR ASCENT AND ASSOCIATED
PRECIPITATION CHANCES WILL REMAIN LOW (GENERALLY AOB 20 PERCENT) AND
INSTEAD DRIVEN BY LOWER AMPLITUDE SOUTHERN STREAM PERTURBATIONS AND
ASSOCIATED SURGES OF LOW LEVEL THETA-E ADVECTION AND BRIEF EROSION
OF A CAPPING INVERSION FRI-SAT...WITH SAID CAPPING MORE LIKELY TO BE
OVERCOME BY DIURNAL HEATING IN AN AIRMASS MORE CHARACTERISTIC OF
APRIL-MAY THAN LATE DECEMBER.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
AS OF 100 WEDNESDAY...
24 HOUR TAF PERIOD: WIDESPREAD ADVERSE AVIATION CONDITIONS WILL
PERSIST THROUGH THE 24 HOUR TAF PERIOD AS AN ANOMALOUSLY MOIST AND
WARM AIRMASS ADVECTS INTO THE AREA.
WIDESPREAD LIFR CIGS AND VSBYS IN DRIZZLE AND FOG HAVE OVERTAKEN THE
AREA. HOWEVER...WITH NEXT ROUND OF SHOWERS SPREADING NORTH INTO THE
AREA BETWEEN 06 TO 12Z...VSBYS SHOULD IMPROVE TO MVFR AND QUITE
POSSIBLY VFR. CEILINGS WILL BE MUCH SLOWER TO IMPROVE...REMAINING
LIFR ACROSS THE AREA THROUGH MID TO LATE MORNING...WITH SOME
TEMPORARY IMPROVEMENT TO MVFR OR VFR...PARTICULARLY AT KRDU/KFAY AND
KRWI THIS AFTERNOON AS WARM SECTOR OVERSPREADS THE AREA. SCATTERED
TO NUMEROUS SHOWERS AND POSSIBLY A FEW THUNDERSTORMS ARE EXPECTED
THROUGH THE AFTERNOON AND EVENING AS WE DESTABILIZE. SOUTHERLY WINDS
WILL INCREASE...GUSTING UP TO 20 TO 25 KTS.
CEILINGS COULD QUICKLY TO IFR TO LIFR ACROSS THE AREA THIS
EVENING...THOUGH A STEADY 10 TO 15KT SOUTHERLY BREEZE SHOULD
PRECLUDE WIDESPREAD FOG DEVELOPMENT.
OUTLOOK: A MOIST DEEP SOUTHWESTERLY FLOW DOWNSTREAM OF THE LONG WAVE
TROUGH IN PLACE ACROSS THE CENTRAL CONUS WILL SUPPORT A PROLONGED
PERIOD OF ADVERSE AVIATION CONDITIONS THROUGH MUCH OF THE PERIOD.
SUB-VFR CONDITIONS IN LOW CLOUDS/STRATUS WILL ALSO BE LIKELY EACH
MORNING... ALONG WITH THE TREAT OF SOME SHOWERS EACH DAY.
&&
.CLIMATE...
HERE ARE THE AREA RECORD MAXIMUMS AND HIGH MINIMUMS FOR DECEMBER 24TH
AND 25TH. RECORDS HAVE BEEN KEPT IN THE GREENSBORO AREA SINCE
1903... IN THE RALEIGH AREA SINCE 1887... AND IN THE FAYETTEVILLE
AREA SINCE 1910.
DEC 24: RECORD MAXIMUM HIGH MINIMUM
GREENSBORO 71 (1964) 52 (1904)
RALEIGH 75 (1931) 59 (1891)
FAYETTEVILLE 78 (1931) 66 (1990)
DEC 25: RECORD MAXIMUM HIGH MINIMUM
GREENSBORO 74 (1955) 58 (1932)
RALEIGH 75 (1955) 63 (1932)
FAYETTEVILLE 79 (1932) 68 (1932)
&&
.RAH WATCHES/WARNINGS/ADVISORIES... NONE.
&&
$$
SYNOPSIS...2
NEAR TERM...CBL
SHORT TERM...2
LONG TERM...2
AVIATION...CBL
CLIMATE...HARTFIELD/BLAES
AREA FORECAST DISCUSSION
NWS RALEIGH NC
355 AM EST WED DEC 23 2015
.SYNOPSIS...AN UNSEASONABLY WARM AND MOIST AIR MASS OVER
CENTRAL NC WILL YIELD ABUNDANT RAINFALL ACROSS THE REGION THROUGH
THURSDAY. RECORD WARMTH IS EXPECTED THROUGH THE CHRISTMAS HOLIDAY
WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 355 AM WEDNESDAY...
...FLASH FLOOD WATCH CONTINUES ACROSS THE WESTERN PIEDMONT...
A SHORTWAVE TROUGH EMBEDDED WITHIN LARGER-SCALE TROUGH SITUATED
ACROSS MUCH OF THE CONUS WILL ADVANCE NEWD FROM THE SRN PLAINS
TOWARDS THE UPPER GREAT LAKES. ACCOMPANYING DEEPENING SFC LOW WILL
FOLLOW SUITE...TRACKING NEWD FROM THE MID-MO VALLEY TO THE UPPER MS
VALLEY BY LATE AFTERNOON. WHILE THESE FEATURES ARE A LITTLE WAYS
FROM HOME...DEEP SOUTHERLY FLOW ON THE EAST SIDE OF THE TROUGH WILL
ADVECT MODIFIED GULF AIR NORTHWARD INTO THE AREA...BRINGING
ANOMALOUS MOIST AND WARM AIR INTO THE AREA. PWATS ARE FORECAST TO
INCREASE TO 1.6-1.9"(4-5 STANDARD DEVIATIONS ABOVE NORMAL)...WHICH
WILL RIVAL MAX DECEMBER VALUES AT KGSO(1.65"-DATING BACK TO
1948)...WHILE TONIGHTS LOW TEMPERATURES WILL STRUGGLE TO DROP OUT OF
THE 70S AT MOST LOCATIONS...AGAIN HAVING A GOOD CHANCE OF MATCHING
THE ALL-TIME WARMEST DECEMBER MINIMUM TEMPERATURE ON RECORD(RDU-
69...FAY-69...GSO-65).
TWO MAIN CONCERNS ARE: 1)PERIODS OF MODERATE TO HEAVY RAINFALL THAT
MAY RESULT IN BOTH FLASHING FLOODING AS WELL AS MINOR FLOODING
ON AREAS RIVERS AND CREEKS AND 2)ISOLATED THREAT OF SEVERE STORMS
LATER TODAY.
FLOOD THREAT: LATEST RADAR TRENDS SHOW AN UPTICK IN CONVECTION
BREAKING OUT ACROSS THE AREA...FUELED BY A STRENGTHENING 50-60KT S-
SW LOW-LEVEL FLOW TO THE EAST OF THE AMPLIFYING SYSTEM TO OUR WEST.
MOST RECENT HRRR SIMULATIONS ARE HANDLING THE CONVECTION
BEST...DEPICTING THE HEAVIEST RAINFALL THIS MORNING ALONG AND EAST
OF HIGHWAY 1. THE AFOREMENTIONED HIGH MOISTURE ANOMALIES WILL
SUPPORT THE POTENTIAL FOR 1.5-2.0"/HOUR RAINFALL RATES OVER THESE
AREAS THIS MORNING THAT WOULD LIKELY CAUSE SOME LOCALIZED FLOODING
GIVEN SATURATED SOILS. HAVE ENTERTAINED THE IDEA OF EXPANDING THE
FLOOD WATCH TO INCLUDE COUNTIES ACROSS THE SANDHILLS AND CENTRAL
PIEDMONT...BUT AS PRECIP HAS BECOME MORE CONVECTIVE IN NATURE...ANY
SUCH HEAVY PRECIP WOULD BE FAIRLY LOCALIZED. WITH A SECOND ROUND OF
SHOWERS AND POSSIBLY A FEW STRONG TO SEVERE STORMS EXPECTED LATER
THIS AFTERNOON AS WARM SECTOR BECOMES ESTABLISHED OVER THE
AREA...AREAS IN THE WATCH COULD STILL SEE LOCALIZED HEAVY AMOUNTS OF
ONE TO TWO INCHES. AS SUCH... WILL KEEP THE FLASH FLOOD WATCH
CONFINED TO THE WESTERN PIEDMONT.
SEVERE THREAT: AS TEMPS CLIMB INTO THE LOWER TO MID 70S AND SFC
DEWPOINTS APPROACH UPPER 60S TO NEAR 70...MODELS SHOW 500-1000 J/KG
OF MUCAPE(HIGHEST IN THE EAST)DEVELOPING OVER THE AREA. 40-50KT DEEP
SHEAR AND SHERBE VALUES APPROACHING 1.0 COULD SUPPORT A FEW STRONG
TO SVR WIND GUSTS AND POSSIBLY AN ISOLATED TORNADO. WILL CONTINUE TO
ADVERTISE SEVERE POTENTIAL ACROSS THE EASTERN HALF OF THE FORECAST
AREA IN THE HWO.
&&
.SHORT TERM /THURSDAY AND THURSDAY NIGHT/...
AS OF 200 AM THURSDAY...
THU AND THU NIGHT: STILL SOME DIFFERENCES IN THE MODELS WITH RESPECT
TO RAIN...THUS THERE IS STILL SOME UNCERTAINTY. HOWEVER...IT IS
LOOKING LIKE THURSDAY COULD BE RELATIVELY DRY...BUT WILL KEEP A
CHANCE OF SOME RAIN IN THE FORECAST. RAIN SHOULD NOT BE NEARLY AS
WIDESPREAD AS IN PRECEDING DAYS. BEST CHANCES FOR CONVECTION WILL
BE IN THE NORTHWEST...ESPECIALLY IN THE AFT/EVE AND INTO THE
OVERNIGHT. HIGHEST TEMPERATURES OF THE LONG TERM ARE STILL EXPECTED
ON THURSDAY AS THE SOUTHERLY WARM ADVECTION PEAKS. HIGHS IN THE LOW
TO MID 70S NW TO AROUND 80 DEGREES IN THE SE. LOWS GENERALLY IN THE
MID 60S.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 200 PM TUESDAY...
FRI THROUGH SUN: AS OF THE LATEST MEDIUM RANGE MODEL RUNS...THIS
PERIOD WILL LIKELY BE DOMINATED BY SUB-TROPICAL RIDGING ALOFT OVER
THE SOUTHEAST U.S.. SOUTHERLY TO SOUTHWESTERLY RETURN FLOW AROUND
THE SURFACE HIGH WILL CONTINUE TO USHER WARM MOIST AIR INTO THE
REGION...RESULTING IN A VERY WARM AND MOIST PERIOD FOR THIS TIME OF
YEAR. THE OCCASIONAL UPPER LEVEL DISTURBANCE RIDING THE RIDGE MAY
GENERATING ENOUGH LIFT IN THE ANOMALOUSLY WARM MOIST AIRMASS TO KICK
OFF SOME SHOWERS...MAINLY IN THE AFT/EVE HOURS. THE GENERAL PRECIP
TREND FOR THIS PERIOD WILL BE CHARACTERIZED BY A LULL DURING THE
OVERNIGHT AND MORNING HOURS AND HIGHEST CHANCES DURING THE AFT/EVE.
THE INITIAL FRONTAL SURGE THAT WAS ORIGINALLY EXPECTED TO PUSH SOUTH
INTO THE AREA ON FRIDAY WILL LIKELY STAY WELL TO THE NORTH THROUGH
AT LEAST SUNDAY EVENING. LOWS THROUGH THE PERIOD WILL BE FAIRLY
CONSISTENT...AND WELL ABOVE NORMAL...IN THE MID 50S TO LOW 60S.
HIGHS WILL LIKELY FLUCTUATE A BIT MORE...BUT GENERALLY STAY BETWEEN
THE MID 60S AND UPPER 70S...WHICH IS 10-15 DEGREES ABOVE NORMAL FOR
LATE DECEMBER.
MONDAY AND MONDAY NIGHT...THE GFS AND ECMWF VARY ON WHETHER THEY
THINK A SECONDARY SURGE WILL PUSH FAR ENOUGH SOUTH TO MOVE INTO
CENTRAL NC FOR THE BEGINNING OF THE WEEK. WILL HOLD OFF ON MAKING
ANY DRASTIC CHANGES TO THE PREVIOUS FORECAST FOR EARLY NEXT WEEK
UNTIL THERE IS BETTER AGREEMENT ONE WAY OR THE OTHER.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
AS OF 100 WEDNESDAY...
24 HOUR TAF PERIOD: WIDESPREAD ADVERSE AVIATION CONDITIONS WILL
PERSIST THROUGH THE 24 HOUR TAF PERIOD AS AN ANOMALOUSLY MOIST AND
WARM AIRMASS ADVECTS INTO THE AREA.
WIDESPREAD LIFR CIGS AND VSBYS IN DRIZZLE AND FOG HAVE OVERTAKEN THE
AREA. HOWEVER...WITH NEXT ROUND OF SHOWERS SPREADING NORTH INTO THE
AREA BETWEEN 06 TO 12Z...VSBYS SHOULD IMPROVE TO MVFR AND QUITE
POSSIBLY VFR. CEILINGS WILL BE MUCH SLOWER TO IMPROVE...REMAINING
LIFR ACROSS THE AREA THROUGH MID TO LATE MORNING...WITH SOME
TEMPORARY IMPROVEMENT TO MVFR OR VFR...PARTICULARLY AT KRDU/KFAY AND
KRWI THIS AFTERNOON AS WARM SECTOR OVERSPREADS THE AREA. SCATTERED
TO NUMEROUS SHOWERS AND POSSIBLY A FEW THUNDERSTORMS ARE EXPECTED
THROUGH THE AFTERNOON AND EVENING AS WE DESTABILIZE. SOUTHERLY WINDS
WILL INCREASE...GUSTING UP TO 20 TO 25 KTS.
CEILINGS COULD QUICKLY TO IFR TO LIFR ACROSS THE AREA THIS
EVENING...THOUGH A STEADY 10 TO 15KT SOUTHERLY BREEZE SHOULD
PRECLUDE WIDESPREAD FOG DEVELOPMENT.
OUTLOOK: A MOIST DEEP SOUTHWESTERLY FLOW DOWNSTREAM OF THE LONG WAVE
TROUGH IN PLACE ACROSS THE CENTRAL CONUS WILL SUPPORT A PROLONGED
PERIOD OF ADVERSE AVIATION CONDITIONS THROUGH MUCH OF THE PERIOD.
SUB-VFR CONDITIONS IN LOW CLOUDS/STRATUS WILL ALSO BE LIKELY EACH
MORNING... ALONG WITH THE TREAT OF SOME SHOWERS EACH DAY.
&&
.CLIMATE...
HERE ARE THE AREA RECORD MAXIMUMS AND HIGH MINIMUMS FOR DECEMBER 24TH
AND 25TH. RECORDS HAVE BEEN KEPT IN THE GREENSBORO AREA SINCE
1903... IN THE RALEIGH AREA SINCE 1887... AND IN THE FAYETTEVILLE
AREA SINCE 1910.
DEC 24: RECORD MAXIMUM HIGH MINIMUM
GREENSBORO 71 (1964) 52 (1904)
RALEIGH 75 (1931) 59 (1891)
FAYETTEVILLE 78 (1931) 66 (1990)
DEC 25: RECORD MAXIMUM HIGH MINIMUM
GREENSBORO 74 (1955) 58 (1932)
RALEIGH 75 (1955) 63 (1932)
FAYETTEVILLE 79 (1932) 68 (1932)
&&
.RAH WATCHES/WARNINGS/ADVISORIES... NONE.
&&
$$
SYNOPSIS...WSS
NEAR TERM...CBL
SHORT TERM...22
LONG TERM...10
AVIATION...CBL
CLIMATE...HARTFIELD/BLAES
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1227 AM CST WED DEC 23 2015
.UPDATE...
ISSUED AT 1227 AM CST WED DEC 23 2015
THE SURFACE LOW WAS NEAR GRAND FORKS...WITH MOSTLY LOW STRATUS
CLOUDS SURROUNDING THE LOW AND ACROSS MOST OF WESTERN AND CENTRAL
NORTH DAKOTA. LIGHT SNOW CONTINUED ACROSS MUCH OF THE NORTHERN TIER OF
COUNTIES...AND WESTWARD OVER EASTERN MONTANA. THIS IS ASSOCIATED
WITH THE DEFORMATION ZONE THAT EXTENDED SOUTHWESTWARD FROM NEAR
PEMBINA TO NEAR BEACH. SHORT TERM HIGH RES MODELS INDICATE LIGHT
SNOW CONTINUING ACROSS NORTHWEST AND NORTH CENTRAL NORTH DAKOTA FOR
THE REST OF THE EARLY MORNING HOURS...THEN TAPERING OFF LATER
WEDNESDAY MORNING. AS PER THE PREVIOUS UPDATE DISCUSSION...WILL
CONTINUE THE WINTER STORM WARNING FOR THE FAR NORTH CENTRAL. WILL
CONTINUE TO MONITOR THE TRENDS IN RADAR ECHO INTENSITY.
UPDATE ISSUED AT 934 PM CST TUE DEC 22 2015
...WILL CONTINUE THE WINTER STORM WARNING FAR NORTH CENTRAL...
SURFACE LOW PRESSURE OVER EAST CENTRAL NORTH DAKOTA WITH UPPER LOW
OVER SOUTHWEST MANITOBA. WARM SECTOR PRECIPITATION HAS PRETTY MUCH
LIFTED NORTH THROUGH NORTHERN MINNESOTA WITH MAINLY WRAP AROUND
MOISTURE CAUGHT IN THE DEFORMATION ZONE THAT STRETCHES BACK WEST
ACROSS NORTHERN NORTH DAKOTA AND INTO NORTHEAST MONTANA. LIGHT
SNOW STILL CONTINUING OVER NORTHERN PORTIONS OF PIERCE AND MCHENRY
COUNTY AND PRETTY MUCH MOST OF ROLETTE AND BOTTINEAU COUNTIES.
LATEST MESOSCALE MODELS CONTINUE TO INDICATE THIS AREA OF
PRECIPITATION REMAINING OVER THE WARNING AREA THROUGH AT LEAST 06
UTC AND THEN DISSIPATING...LIFTING NORTH THEREAFTER...WHILE WEAK
SHORTWAVE ENERGY PUSHES FROM NORTHEAST MONTANA INTO WESTERN NORTH
DAKOTA. HAVE UPDATE POPS TO KEEP CATEGORICAL POPS ACROSS THE
NORTH THROUGH 06 UTC...AND THEN SLOWLY TAPERING TO CHANCE POPS
AROUND 12Z. A DEEP DENDRITIC GROWTH LAYER REMAINS ACROSS NORTHERN
NORTH DAKOTA...AND OCCASIONAL BANDS OF HIGHER REFLECTIVITIES
CONTINUE TO DEVELOP ACROSS THE WARNING AREA. THEREFORE WILL
CONTINUE THE WARNING FOR NOW AND WILL TONE DOWN THE ADDITIONAL
SNOWFALL AMOUNTS. MANY AREAS WITHIN THE WARNING AREA HAD RECEIVED
4 TO 7 INCHES THROUGH LATE AFTERNOON...SO COULD SEE SOME MORE
REPORTS OF 6-8 INCHES WHEN MORNING REPORTS COME IN THURSDAY.
WARNING DOES EXPIRE AT 12 UTC BUT THE OVERNIGHT SHIFT CAN CANCEL
EARLY IF SNOW ENDS.
BACK IN NORTHWEST NORTH DAKOTA...LITTLE IF ANY SNOW FELL DURING
THE DAY WEDNESDAY...BUT WITH SNOW THIS EVENING...CONTINUING INTO
THURSDAY MORNING...WOULD EXPECT A FEW REPORTS OF 1-2 INCHES.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 253 PM CST TUE DEC 22 2015
HEAVY SNOW NORTH CENTRAL THROUGH EARLY THIS EVENING HIGHLIGHTS THE
SHORT TERM FORECAST.
AS OF 2130 UTC...A SECONDARY SHORTWAVE EVIDENT ON WATER VAPOR HAS
PROPAGATED NORTHEAST OUT OF NORTH CENTRAL SOUTH DAKOTA INTO SOUTH
CENTRAL NORTH DAKOTA...AS REFLECTED IN THE INTENSIFICATION OF
SNOWFALL ACROSS SOUTH CENTRAL NORTH DAKOTA OVER THE PAST ONE TO
TWO HOURS. THIS WAVE WILL CONTINUE TO PROPAGATE NORTHEAST AND
INTERACT WITH THE TROWAL ACROSS NORTH CENTRAL AND NORTHEAST NORTH
DAKOTA TO CONTINUE TO SUPPORT HEAVY SNOWFALL THROUGH EARLY THIS
EVENING. THE 17-20 UTC HRRR AND RAP ITERATIONS HAVE HANDLED THE
MESOSCALE BANDING OF SNOWFALL WELL THROUGH THE AFTERNOON AND WILL
FOLLOW THEIR SOLUTIONS THROUGH THE EVENING...BLENDED TO THE 12 UTC
GLOBAL SUITE LATE TONIGHT INTO WEDNESDAY MORNING. OVERALL...STORM
TOTAL SNOWFALL ACCUMULATIONS OF 6 TO 8 INCHES REMAIN UNCHANGED FOR
THE TOWNER...RUGBY...BOTTINEAU AND ROLETTE AREAS...WITH LOCALLY
HIGHER AMOUNTS. ELSEWHERE FOR TONIGHT INTO WEDNESDAY
MORNING...LIGHT SNOW IS EXPECTED. THIS IS IN ASSOCIATION WITH THE
WEAKENING TROWAL AND A WAVE CURRENTLY ACROSS NORTH CENTRAL
MONTANA THAT WILL PROPAGATE SOUTHEAST. ADDITIONAL SNOWFALL
ACCUMULATIONS OF AROUND ONE...TO POSSIBLY TWO INCHES ACROSS THE
WEST INTO THE SOUTH CENTRAL ARE FORECAST.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 253 PM CST TUE DEC 22 2015
COOLING TEMPERATURES INTO THE WEEKEND HIGHLIGHT THE EXTENDED
FORECAST.
THE 12 UTC DETERMINISTIC AND ENSEMBLE SUITES ARE IN AGREEMENT ON
A BROAD...UPPER LEVEL WESTERN AND CENTRAL CONUS TROUGH TO BEGIN
THE PERIOD TO POSSIBLY TRANSITION TO SPLIT FLOW BY THE
WEEKEND...POTENTIALLY PLACING THE NORTHERN PLAINS IN NORTHWEST
FLOW ALOFT WITH THE NORTHERN STREAM. THIS SUPPORTS A POSSIBLE COOL
DOWN INTO THE WEEKEND. OVERALL...THE CHRISTMAS TRAVEL OUTLOOK
LOOKS GOOD WITH RATHER QUIET WEATHER.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1227 AM CST WED DEC 23 2015
MVFR TO OCCASIONAL IFR CONDITIONS ARE EXPECTED ACROSS WESTERN AND
CENTRAL NORTH DAKOTA THIS MORNING AND THROUGH MUCH OF THE DAY ON
WEDNESDAY. LIGHT WEST FLOW TONIGHT WILL TURN NORTH TO NORTHWEST
AND INCREASE TO UP TO 15 MPH ON WEDNESDAY AFTERNOON.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL 6 AM CST EARLY THIS MORNING FOR
NDZ004-005-012-013.
&&
$$
UPDATE...JV
SHORT TERM...AYD
LONG TERM...AYD
AVIATION...JV
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
1133 PM CST TUE DEC 22 2015
.DISCUSSION...
UPDATED FOR 06Z AVIATION DISCUSSION
&&
.PREV DISCUSSION... /ISSUED 907 PM CST TUE DEC 22 2015/
UPDATE...
A WARM FRONT CURRENTLY STRETCHES FROM NEAR SEARCY ARKANSAS TO
TIPTONVILLE TENNESSEE. DENSE FOG HAS DEVELOPED JUST AHEAD OF THE
FRONT ACROSS PORTIONS OF NORTHEAST ARKANSAS AND THE MISSOURI
BOOTHEEL. THE FOG WILL DISSIPATE AS THE FRONT PUSHES
NORTHWARD...MAY NEED TO EXTEND THE TIMING FOR THE DENSE FOG
ADVISORY FOR RANDOLPH AND LAWRENCE COUNTIES A LITTLE PAST MIDNIGHT
BUT WILL HOLD OFF ON A DECISION FOR ANOTHER ONE TO TWO HOURS.
TEMPERATURES HAVE DROPPED LOWER THAN THE FORECASTED LOWS ACROSS
NORTHEAST ARKANSAS DUE TO THE SLOWNESS OF THE FRONT. HOWEVER THEY
ARE LIKELY AT OR NEAR THE LOW AT THIS TIME AND SHOULD RISE
OVERNIGHT AS THE FRONT PUSHES THROUGH.
MEANWHILE...STILL WAITING FOR GENERATION OF THUNDERSTORMS TO OCCUR
IN ARKLATEX WHICH SHOULD HAPPEN IN THE NEXT 2 TO 3 HOURS. THESE
THUNDERSTORMS WILL PUSH INTO EASTERN ARKANSAS BETWEEN 4-6 AM CST. HOWEVER
A MORE IMMEDIATE CONCERN MAY BE THE LARGE AREA OF RAIN THAT IS
OCCURRING ACROSS SOUTHERN MISSISSIPPI TONIGHT. THE RAIN SEEMS TO
BE ASSOCIATED WITH A SECONDARY BOUNDARY. THE 18Z GFS SHOWS THIS
AREA WITH SOME ADDITIONAL DEVELOPMENT OVER NE LOUISIANA CREEPING
INTO NORTH MISSISSIPPI OVERNIGHT WHILE THE NAM KEEPS THE RAIN TO
THE SOUTH AND EAST OF THE CWA. THE HRRR HAS BEEN IN AGREEMENT WITH
THE NAM UP UNTIL THE LAST RUN AT 1Z WHICH SEEMS TO BE SOMEWHAT IN
BETWEEN. FOR NOW LIKELY POPS ACROSS THE WESTERN HALF OF THE CWA
AND ACROSS PORTIONS OF NORTHEAST MISSISSIPPI SEEMS REASONABLE.
KRM
DISCUSSION... /ISSUED 308 PM CST TUE DEC 22 2015/
THE POTENTIAL FOR A SIGNIFICANT SEVERE THUNDERSTORM OUTBREAK
ACROSS THE ENTIRE MIDSOUTH CONTINUES TO INCREASE STRONG TORNADOES
ARE POSSIBLE...
AN ABNORMAL WEATHER PATTERN IS IN PLACE ACROSS THE
MIDSOUTH...FEATURING VERY UNSTABLE CONDITIONS AND WHAT LOOKS TO BE
AN ADEQUATE AMOUNT OF SHEAR TO BALANCE THE THERMODYNAMICS.
TEMPERATURES ARE IN THE MIDDLE 60S TO LOW 70S ACROSS THE
REGION...AROUND 25 DEGREES ABOVE NORMAL. DEW POINTS ARE IN THE
UPPER 50S TO LOW 60S...BUT SOUTHERLY WIND WILL KEEP DEWPOINTS
RISING AS GULF MOISTURE FLOODS THE MIDSOUTH. OVER THE NEXT 24
HOURS OR SO A VERY BROAD TROUGH WILL SHIFT ACROSS THE PLAINS. LATE
TONIGHT INTO EARLY TOMORROW ITS AXIS SHOULD BE OVER CENTRAL
OKLAHOMA...WITH A NEGATIVELY TILTED SHORTWAVE APPROACHING THE
MISSISSIPPI RIVER VALLEY. ONE OF THE MORE SIGNIFICANT CHANGES IN
MODEL GUIDANCE OVER THE LAST 24 HOURS IS THE DEVELOPMENT OF
DIURNAL THUNDERSTORMS ALONG AND WEST OF THE MISSISSIPPI RIVER
TONIGHT. BOTH THE NAM AND GFS INDICATE IN EXCESS OF 1000 J/KG CAPE
IN PLACE AS THE SHORTWAVE APPROACHES. A STRONG LLJ NEAR 100KT IS
ALREADY IN PLACE...STREAMING FROM THE SOUTHWEST GULF OF MEXICO
ACROSS THE MIDSOUTH. IF THUNDERSTORMS DEVELOP...THEY WOULD ALMOST
CERTAINLY QUICKLY STRENGTHEN TO SEVERE LIMITS. SIGNIFICANT HEIGHT
FALLS...ON THE ORDER OF 4DM/12HR WILL BEGIN AROUND MIDNIGHT...WITH
AS MUCH AS 8DM/12HR MY MIDDAY TOMORROW. THE STORM PREDICTION
CENTER HAS INCLUDED MOST OF THE MIDSOUTH WEST OF THE MISSISSIPPI
RIVER IN AN ENHANCED OUTLOOK FOR SEVERE THUNDERSTORMS TONIGHT.
STILL FEEL LIKE THE MOST WIDESPREAD AND STRONGEST STORMS WILL BE
TOMORROW...WITH THE HIGHEST THREAT ALONG THE SOUTH OF THE INTERSTATE
40 CORRIDOR...BUT SEVERE WEATHER IS POSSIBLE ACROSS ALL OF THE
MIDSOUTH. THE STRONG LLJ WILL BRING A COASTAL AIRMASS ACROSS THE
MIDSOUTH TOMORROW AFTERNOON. DEW POINTS WILL CERTAINLY BE IN THE
MIDDLE 60S ACROSS MOST OF THE AREA...AND MAY CLIMB INTO THE UPPER
60S IN NORTH MISSISSIPPI. RESULTING SURFACE BASED INSTABILITY
COULD EXCEED 1200J/KG. LOW LEVEL LAPSE RATES ON THE ORDER OF 6C
AND 30-40 DEGREES OF DIFFLUENCE ALOFT SHOULD HELP MAINTAIN
SUSTAINED HEALTHY UPDRAFTS. 0-3KT SRH WILL BE IN EXCESS OF
300M^2/S^2 IN NORTH MISSISSIPPI TOMORROW AT MIDDAY...WEAKENING
ONLY SLIGHTLY TO AROUND 250M^2/S^2 BY SUNSET. AS A RESULT A FEW
STRONG TORNADOES ARE POSSIBLE...ESPECIALLY IN NORTH MISSISSIPPI.
IN ADDITION...DAMAGING WIND AND LARGE HAIL ARE THREATS AREA WIDE
TOMORROW. THE SEVERE THREAT SHOULD DIMINISH AFTER SUNSET.
THURSDAY SHOULD BE MOSTLY DRY...ALTHOUGH A FEW SHOWERS MAY LINGER
IN FAR EASTERN PORTIONS OF THE MIDSOUTH NEAR THE ALABAMA STATE
LINE AND TENNESSEE RIVER.
WE WILL REMAIN IN AN ACTIVE PATTERN
AFTER TOMORROW. FRIDAY THROUGH MONDAY...LONG RANGE MODELS INDICATE
THE FRONT WILL BEGIN TO RETURN BACK NORTH AS A WARM FRONT ACROSS
THE FORECAST AREA ON CHRISTMAS DAY. THIS WILL RESULT IN THE
DEVELOPMENT OF ADDITIONAL SHOWERS AND THUNDERSTORMS ACROSS THE MID
SOUTH THURSDAY NIGHT AND ESPECIALLY ON FRIDAY. ADDITIONAL STRONG
TO SEVERE THUNDERSTORMS MAY BE POSSIBLE ON CHRISTMAS DAY. LONG
TERM MODELS BEGIN TO DIVERGE GREATLY WITH RUN TO RUN CONTINUITY AS
AN UPPER LEVEL LOW MOVES FROM THE PLAINS INTO THE MISSISSIPPI
VALLEY TOWARDS EARLY NEXT WEEK. THUS OVERALL CONFIDENCE IN
PRECIPITATION CHANCES MAY NEED TO BE ADJUSTED IN SUBSEQUENT
FORECASTS FOR THIS WEEKEND AND ESPECIALLY EARLY NEXT WEEK.
30
&&
.AVIATION...
06Z TAFS
MVFR CIGS EXPECTED OVERNIGHT. STRENGTHENING SOUTH WINDS AND
RESULTANT MIXING SHOULD HELP PREVENT WIDESPREAD IFR CIGS. A
STRONG STORM SYSTEM WILL TRACK INTO THE REGION AND SHRAS/TSRAS NOW
DEVELOPING OVER EAST TX/LA WILL MOVE INTO THE MIDSOUTH LATE
TONIGHT INTO WED AM. A COUPLE OF ROUNDS OF SHRAS/TSRAS ARE
POSSIBLE ACROSS THE AREA THROUGH EARLY WED EVENING. SEVERE WEATHER
LIKELY. GENERALLY MVFR CIGS EXPECTED THROUGH THE DAY WITH OCNL
IFR CIGS IN THE MORNING IN SHRAS/TSRAS. CONDS WILL BEGIN TO
IMPROVE TO VFR AT KJBR AND KMEM WED EVENING. LOW CLOUDS WILL
LINGER AT KMKL AND KTUP THROUGH THE END OF THE PERIOD.
WINDS WILL QUICKLY INCREASE AND BECOME GUSTY OVERNIGHT. STRONG
GUSTY SOUTH WINDS EXPECTED WED ESPECIALLY AT KJBR/KMEM WHERE GUSTS
COULD HIT 30 KTS. WINDS WILL DIMINISH LATE IN THE AFTERNOON/EARLY
EVENING AND VEER TO THE SW.
SJM
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS CHEYENNE WY
1058 PM MST TUE DEC 22 2015
.UPDATE...ISSUED FOR 06Z AVIATION FORECAST PACKAGE DISCUSSION
BELOW.
PREVIOUS UPDATE ISSUED AT 758 PM MST TUE DEC 22 2015...
ALLOWED WINTER WEATHER ADVISORIES FOR THE ELK MOUNTAIN...
ARLINGTON...AND SOUTHWESTERN CARBON COUNTY TO EXPIRE EARLIER THIS
EVENING GIVEN MOST OF ANY SIGNIFICANT SNOWFALL WILL BE TO THE EAST
AND WINDS HAVE RELAXED TO WHERE BLOWING SNOW ISSUES ARE NOT
EXPECTED TO BE SIGNIFICANT. WYDOT STILL REPORTS SOME ROADS AS
SLICK OR SLICK IN SPOTS SO MOTORISTS WILL NEED TO BE ADVISED TO
CHECK THE LATEST ROAD CONDITIONS BEFORE HEADING OUT. WINTER STORM
WARNINGS REMAIN POSTED FOR MORE HEAVY SNOW POTENTIAL THROUGH
TOMORROW IN THE SIERRA MADRE AND SNOWY MOUNTAIN RANGES WEST OF
LARAMIE.
BAND OF LIGHT SNOW EXTENDS FROM NORTHEASTERN COLORADO INTO THE
SOUTHERN NEBRASKA PANHANDLE. A LOT OF THE RADAR RETURNS MAY NOT BE
MAKING IT TO THE SURFACE...AND THE DEEPER MOISTURE AND HIGHER
CLOUDTOP SIGNATURES ARE MOVING OUT EAST OF CHEYENNE WITH MOST OF
ANY LIGHT TO MODERATE SNOW EXPECTED TO AFFECT THE SOUTHERN
NEBRASKA PANHANDLE...AND RIGHT NOW IT DOESN`T LOOK LIKE THEY WILL
GET MUCH IN THE WAY OF NEW SNOW THIS EVENING OR OVERNIGHT GIVEN
OBSERVATIONS AND RADAR AND SATELLITE RETURNS. THEREFORE WILL KEEP
A CHANCE OF SNOW GOING SOUTHERN NEBRASKA PANHANDLE TO
CHEYENNE...BUT IT ISN`T LOOKING LIKE A FEW INCHES WILL PAN OUT IN
CHEYENNE...MAYBE AN INCH OR SO SIDNEY (LIKELY AT MOST) IF WE GET
ANOTHER BAND DEVELOP TO THE SOUTHWEST AND MOVE ACROSS THEM LATE
TONIGHT.
BASED ON THE CHANCES OF SNOW WE CURRENTLY HAVE ADVERTISED OUT WEST
ACROSS PARTS OF CARBON COUNTY AND ALONG I-80 FROM RAWLINS TO
LARAMIE FOR TOMORROW...WE MAY HAVE TO POST WINTER WEATHER
ADVISORIES AGAIN ON THE EARLY MORNING SHIFT FOR TOMORROW IF NEW
SNOW AMOUNTS COME IN A BIT HIGHER ON OVERNIGHT MODEL RUNS
RESULTING IN A HIGHER POTENTIAL FOR SIGNIFICANT TRAVEL IMPACTS.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 214 PM MST TUE DEC 22 2015
PRIMARY FORECAST CONCERN FOR THE SHORT TERM IS THE POTENTIAL FOR
SNOWFALL ACROSS THE EXTREME SE WYOMING PLAINS EXTENDING INTO THE
SOUTHERN NEBRASKA PANHANDLE THIS EVENING AND TONIGHT. EVERYTHING
ELSE APPEARS ON TRACK...WITH CURRENT KCYS RADAR LOOP SHOWING
SNOWFALL CONTINUING OVER THE MOUNTAINS. SNOTEL OBSERVATIONS ACROSS
THE SIERRA MADRE RANGE SHOW SOME IMPRESSIVE 36 HOUR SNOW
TOTALS...WITH TWO LOCATIONS NEAR BATTLE MOUNTAIN PASS ESTIMATING
BETWEEN 34 TO 42 INCHES OF SNOW SINCE LATE SUNDAY NIGHT. MORE SNOW
IS EXPECTED TONIGHT AND WEDNESDAY...SO THESE TOTALS WILL LIKELY GO
OVER 4 FEET IN A FEW LOCATIONS. MUCH LESS SNOW WAS OBSERVED OVER
THE SNOWY RANGE WITH ONLY ONE LOCATION ABOVE ONE FOOT OF TOTAL
ACCUMULATION. WILL CONTINUE THE WINTER WEATHER ADVISORIES FOR A
FEW OF THE LOWER ELEVATIONS OF CARBON COUNTY INTO THIS EVENING
WITH SOME ADDITIONAL SNOW AND BLOWING SNOW ALONG AND SOUTH OF I80.
ATTENTION THEN SHIFTS EASTWARD TOWARDS LARAMIE...THE CHEYENNE
AREA...AND ACROSS THE SOUTHERN NE PANHANDLE ALONG I80. MODELS ARE
IN PRETTY GOOD AGREEMENT SHOWING AN AREA OF RAPID FRONTOGENESIS
THIS EVENING JUST SOUTH OF THE COLORADO BORDER. MODELS SHOW A
WEAK WAVE OF LOW PRESSURE DEVELOPING ALONG THE FRONT THIS
EVENING...WHICH IS CURRENTLY NEAR DENVER AND STRETCHES EASTWARD
OVER THE PLAINS NEAR I-70 OVER EASTERN COLORADO. THIS FEATURE
APPEARS TO BE FAST MOVING BUT POTENT...WITH EVEN THE HRRR AND NAM
SHOWING SOME MODERATE SNOW FROM THE I80 SUMMIT EASTWARD INTO
THE SOUTHERN NE PANHANDLE. TYPICALLY...GOOD MODEL AGREEMENT WOULD
INCREASE OVERALL CONFIDENCE 6 TO 12 HOURS OUT...BUT THE ISSUE IS
NO MODELS WAS SHOWING THIS FEATURE YESTERDAY. FOR NOW...INCREASED
POP TO 50 PERCENT ALONG THE I80 CORRIDOR INTO SIDNEY NEBRASKA.
WORDED FORECAST FOR OCCASIONAL SNOW AND 1 TO 2 INCHES OF SNOW
ACCUMULATION FOR NOW EVEN THOUGH THE NAM AND GEM ARE A BIT HIGHER.
WITH WESTERLY FLOW JUST OFF THE SURFACE AND RELATIVELY LOW
DEWPOINTS...CONCERNED THERE IS TOO MUCH DRY AIR TO PRODUCE MUCH
SNOWFALL. THE FRONT WILL QUICKLY PUSH SOUTH AND EAST LATE TONIGHT.
ANOTHER ROUND OF SNOW IS POSSIBLE FOR WEDNESDAY...ALTHOUGH MODELS
ARE NOT AS AGGRESSIVE AS THEY WERE YESTERDAY. ANOTHER QUICK MOVING
SHORTWAVE MOVES ACROSS WYOMING DURING THE AFTERNOON AND EVENING
HOURS...WITH SOME LIGHT SNOW ACROSS THE MOUNTAINS AND POTENTIALACROSS
THE EASTERN PLAINS. WINDS WILL ALSO BEGIN TO INCREASE AGAIN LATE
WEDNESDAY AND WEDNESDAY NIGHT AS HIGH PRESSURE NEAR THE SURFACE
BUILDS ON THE WINDWARD SIDE OF THE ROCKY MOUNTAINS. MAY NEED HIGH
WIND HEADLINES FOR THE WIND PRONE AREAS ONCE AGAIN BY EARLY
THURSDAY MORNING WITH GUSTS AROUND 55 TO 60 MPH.
OTHERWISE...BECOMING COLDER EACH DAY WITH HIGHS ON IN THE 20S TO
LOW 30S BY CHRISTMAS EVE.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 245 PM MST TUE DEC 22 2015
NEXT UPPER SYSTEM TO AFFECT THE AREA WILL BE DIGGING OVER THE
WESTERN CONUS THURSDAY NIGHT WITH SW FLOW ALOFT OVER THE CWA. SOME
SNOW SHOWERS SHOULD OCCUR OVER THE HIGHER MTNS THURSDAY NIGHT AS
MOISTURE INCREASES IN THE FLOW OVER THAT AREA. ONE BATCH OF ENERGY
EJECTS NORTHEAST ACROSS THE CWA CHRISTMAS DAY WITH LEE
CYCLOGENESIS OVER SE COLORADO. THIS SHOULD BRING AN AREA OF LIGHT
SNOW TO MUCH OF THE CWA IN THE AFTERNOON AND EVENING BODING FOR A
WHITE CHRISTMAS FOR AT LEAST PARTS OF THE CWA FOR THE 4TH TIME IN
THE LAST 5 YEARS. MEANWHILE THE MAIN ENERGY WITH THE UPPER SYSTEM
STILL PROGGED TO CUT OFF OVER ARIZONA FRIDAY NIGHT WHILE THE SNOW
ENDS OVER OUR CWA. MODELS IN PRETTY GOOD AGREEMENT IN TRACKING THE
UPPER LOW ACROSS THE SOUTHERN ROCKYS INTO THE SOUTHERN PLAINS
SATURDAY THROUGH SUNDAY WITH THE GFS A BIT FASTER. THIS KEEPS THE
CWA DRY BUT COLD COMPLIMENTS OF A COLD SFC HIGH THAT WILL SETTLE
OVER THE NORTHERN PLAINS. THE UPPER LOW THEN LIFTS NORTHEAST ON
MONDAY AND MAY BRING A GLANCING SHOT OF WRAP-AROUND LIGHT SNOW TO
THE PANHANDLE. OTHERWISE WARMING SOME MONDAY AS SFC DOWNSLOPE FLOW
SETS UP BEFORE ANOTHER UPPER SHORTWAVE PASSES BY MONDAY NIGHT
BRINGING SOME COOLER AIR AGAIN AS WELL AS SOME MTN SNOW SHOWERS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 951 PM MST TUE DEC 22 2015
WILL CARRY VFR VIS IN LIGHT SNOW FOR SIDNEY THROUGH 07Z THEN
DRY SLOT SHOULD WORK IN FROM THE WEST WITH VFR EXPECTED THROUGH
THE REST OF THE PERIOD. REST OF AIRPORTS VFR THROUGH THE PERIOD
WITH THE EXCEPTION OF RAWLINS AND LARAMIE WHERE WE WILL INTRODUCE
SNOW AGAIN STARTING LATE MORNING RAWLINS WHERE WE HAVE CEILINGS
AND VISIBILITIES DROPPING IN LIGHT SNOW DOWN TO MVFR THEN IFR IN
THE AFTERNOON...THEN STARTING LIGHT SNOW AT LARAMIE IN THE
AFTERNOON DROPPING CEILINGS DOWN TO MVFR.
&&
.FIRE WEATHER...
ISSUED AT 214 PM MST TUE DEC 22 2015
NO FIRE WEATHER CONCERNS IN THE NEAR FUTURE WITH AFTERNOON
HUMIDITY VALUES WELL OUTSIDE OF CRITICAL THRESHOLDS IN ADDITION TO
SEVERAL CHANCES FOR PRECIPITATION OVER THE NEXT SEVERAL DAYS.
HEAVY MOUNTAIN SNOW IS ALREADY OCCURRING IN THE SNOWY/SIERRA
MADRES...AND IS LIKELY TO CONTINUE THROUGH THU.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...WINTER STORM WARNING UNTIL 5 PM MST WEDNESDAY FOR WYZ112-114.
NE...NONE.
&&
$$
UPDATE...JG
SHORT TERM...TJT
LONG TERM...RE
AVIATION...ZF
FIRE WEATHER...TJT
AREA FORECAST DISCUSSION
NWS TAUNTON MA
1028 AM EST WED DEC 23 2015
.SYNOPSIS...
UNUSUALLY WARM DECEMBER WEATHER WILL CONTINUE FOR THE NEXT SEVERAL
DAYS...PROBABLY BREAKING MANY RECORDS. PERIODS OF WET WEATHER WILL
ACCOMPANY THE WARMTH...MAINLY WEDNESDAY AFTERNOON AND EVENING...
AND AGAIN THIS WEEKEND INTO EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
1030 AM UPDATE...
DENSE FOG HAS LIFTED EXCEPT ACROSS MUCH OF THE REGION WITH JUST
SOME LOWER VSBYS LINGERING IN PORTIONS OF THE CT VALLEY WHICH
SHOULD IMPROVE BY NOON. HOWEVER...FOG WILL LIKELY REDEVELOP LATER
TODAY INTO TONIGHT FROM SOUTH TO NORTH AS WARM FRONT
APPROACHES...AND AREAS OF DENSE FOG EXPECTED. USING THE HRRR FOR
TIMING OF RAINFALL HAS ONSET 19-20Z IN THE CT VALLEY THEN
OVERSPREADING REST OF SNE 21-23Z. TEMPS WILL BE TRICKY TODAY AND
MAY REMAIN IN THE UPPER 40S NEAR THE NH BORDER WHILE REACHING THE
MID/UPPER 50S BY LATE IN THE DAY NEAR THE S COAST.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/...
TONIGHT...THE WARM FRONT MOVES NORTHWARD THROUGH SOUTHERN NEW
ENGLAND. WITH THAT...RAIN...FOG...AND WARM TEMPERATURES ARE
EXPECTED TO CONTINUE. WIDESPREAD RAIN WILL TRANSITION MORE TO
SHOWERS WITH THE POTENTIAL FOR THUNDER CONTINUING THROUGH THE NIGHT.
AN ADDITIONAL HALF AN INCH OF RAIN IS EXPECTED OVERNIGHT. EXPECT
WIDESPREAD AREAS OF FOG DURING THE OVERNIGHT...POTENTIALLY WITH
VISIBILITIES DOWN TO A QUARTER OF A MILE. TEMPERATURES WILL BE MILD
ONCE AGAIN...WITH A HIGH LIKELIHOOD OF BREAKING THE RECORD WARM LOW
TEMPERATURES. THE CURRENT RECORDS CAN BE FOUND BELOW IN THE CLIMATE
SECTION.
THURSDAY...AS WE REMAIN IN THE WARM SECTOR...EXPECT THIS TO BE THE
WARMEST DAY OF THE WEEK. SOUTHWESTERLY WINDS AND 925MB TEMPERATURES
BETWEEN 15 AND 16 DEG C WILL LEAD TO HIGH TEMPERATURES IN THE MID TO
UPPER 60S TO EVEN 70 DEGREES FOR MUCH OF SOUTHERN NEW ENGLAND. THIS
WOULD BE DESPITE OVERCAST SKIES AND RAIN. SHOULD THIS FORECAST COME
TO FRUITION /AND ALL INDICATIONS ARE IT WILL/...THIS WILL SHATTER
THE PREVIOUS RECORD HIGHS FOR THIS DATE. IN ADDITION...IT WILL BE
VERY HUMID...PARTICULARLY FOR DECEMBER...WITH DEWPOINTS IN THE 60S.
MUCH OF THE DAY SHOULD BE DRY...THOUGH THERE IS POTENTIAL FOR A FEW
LINGERING SHOWERS...PARTICULARLY EARLY IN THE DAY. FINALLY...A
STRONG LOW LEVEL JET WILL BE IN PLACE ALONG THE COAST.
HOWEVER...AN INVERSION WILL LIKELY LIMIT WIND GUSTS TO LESS THAN
30 MPH ACROSS THE CAPE AND ISLANDS.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
HIGHLIGHTS...
* CONTINUED UNSEASONABLY MILD CHRISTMAS DAY
* FAST-MOVING AND ACTIVE PATTERN WILL BRING MULTIPLE PRECIPITATION
CHANCES THIS WEEKEND INTO EARLY NEXT WEEK
* UNSEASONABLY MILD AGAIN SUNDAY...THEN TURNING COLDER MONDAY
OVERVIEW...
RATHER GOOD AGREEMENT AMONG THE 23/00Z GUIDANCE SUITE FOR MOST OF
THIS PERIOD. HAVE ABOVE AVERAGE CONFIDENCE IN THE FORECAST INTO
SUNDAY. WILL FOLLOW A CONSENSUS SOLUTION FOR THIS PORTION OF THE
FORECAST.
BIG DIFFERENCES IN THE EVOLUTION OF THE MID LEVEL FLOW EARLY NEXT
WEEK. OPERATIONAL GFS IS MUCH MORE PROGRESSIVE THAN THE
INTERNATIONAL MODELS...AND EVEN THE GEFS MEAN. FLOW ALOFT SHOULD
BE FAST...SO CAN SEE REASONS WHY THE GFS WOULD BE SO PROGRESSIVE.
WITH LOWER CONFIDENCE IN THE DETAILS THOUGH...WILL ONLY TREND THE
FORECAST IN THAT DIRECTION.
PERSISTENT LARGE SUBTROPICAL RIDGE OFF SE US COAST WILL REMAIN
THROUGH THE EXTENDED PERIOD...WITH SOUTHERN NEW ENGLAND REMAINING
WITHIN THE UPPER LEVEL JET AXIS. THIS WILL RESULT IN MULTIPLE
PERIODS OF UNSETTLED WEATHER AND TEMPERATURES AVERAGING WELL ABOVE
NORMAL. GUIDANCE IS SIGNALING A SPLIT FLOW PATTERN DEVELOPING THIS
WEEKEND...WITH MORE OF A NORTHERN STREAM INFLUENCE EARLY NEXT
WEEK. THIS SHOULD LEAD TO A TEMPORARY RETURN TO MORE SEASONABLE
TEMPERATURES. ANY COOLING WILL BE SHORT-LIVED AS RIDGING BECOMES
RE-ESTABLISHED. DEPENDING ON TIMING OF NEXT SYSTEM LIFTING THROUGH
THE GREAT LAKES...THERE IS A CHANCE OF SOME WINTRY PRECIPITATION
EARLY NEXT WEEK. AGAIN...LOW CONFIDENCE IN THE DETAILS AT THIS
TIME RANGE.
DETAILS...
CHRISTMAS DAY...A WEAK FRONT WILL BE MOVING OFFSHORE...BUT
LIKELY STALLS JUST OFF THE COAST AS THERE IS NOT MUCH PUSH WITH SW
FLOW ALOFT. THINKING THERE WILL BE AT LEAST A BRIEF PERIOD OF
CLEARER SKIES. OVERRUNNING MOISTURE LIKELY RETURNS FRIDAY NIGHT.
CONSENSUS SOLUTIONS SUGGEST SOME SHOWERS MOVE IN FRIDAY NIGHT AS
WELL. IT WILL REMAIN UNSEASONABLY MILD. RECORD TEMPERATURES COULD
BE CHALLENGED AGAIN AT KPVD. SEE CLIMATE SECTION BELOW.
SATURDAY AND SUNDAY...
HIGH PRESSURE TO THE NORTH WILL MOVE OFFSHORE...ALLOWING THE FRONT
TO OUR SOUTH TO RETURN NORTH AS A WARM FRONT. MORE SHOWERS
EXPECTED SATURDAY INTO SATURDAY NIGHT...BUT EXACT TIMING IS
UNCERTAIN. A STRONG COLD FRONTAL PASSAGE SUNDAY WILL LEAD TO
ANOTHER PERIOD OF SHOWERS. STILL UNSEASONABLY WARM. THERE REMAINS
A CHANCE FOR NEAR RECORD WARMTH AGAIN AT ALL 4 CLIMATE SITES
SUNDAY.
MONDAY AND TUESDAY...
VERY STRONG HIGH PRESSURE BUILDS INTO OUR REGION FROM THE NORTH
MONDAY. THIS WILL LIKELY MEAN LOWER...BUT STILL SEASONABLE...
TEMPERATURES. THIS HIGH PRESSURE EVENTUALLY MOVES OFFSHORE.
DEPENDING ON HOW FAST A LOW PRESSURE MOVES THROUGH THE GREAT
LAKES...WE COULD SEE OUR FIRST LEGITIMATE SHOT A WINTRY WEATHER
SOMETIME DURING THIS PERIOD. IT IS MORE LIKELY ANY PRECIPITATION
WOULD BE ALL RAIN BY TUESDAY AFTERNOON. THIS POTENTIAL WILL NEED
TO BE MONITORED THIS WEEK. LOWEST CONFIDENCE PORTION OF THIS
FORECAST.
&&
.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
TODAY...HIGH CONFIDENCE. PATCHY IFR FOG CT VALLEY WILL IMPROVE
AROUND MIDDAY...OTHERWISE A BRIEF PERIOD OF VFR EXPECTED INTO
THIS AFTERNOON BEFORE CONDITIONS DETERIORATE MID TO LATE AFTERNOON
WITH IFR STRATUS AND FOG AND RAIN DEVELOPING.
TONIGHT...HIGH CONFIDENCE. IFR CIGS/VSBYS EXPECTED IN RAIN/FOG WITH
SOME MARGINAL IMPROVEMENT TO MVFR BY 12Z THURSDAY ACROSS WESTERN
MA/CT. LOW PROBABILITY OF ISOLATED THUNDERSTORMS.
THURSDAY...MODERATE CONFIDENCE. OVERCAST SKIES WILL CONTINUE
THROUGH THE DAY BUT CONDITIONS SHOULD GRADUALLY IMPROVE FROM
MVFR/IFR TO VFR.
KBOS TERMINAL...HIGH CONFIDENCE IN TRENDS. LOWER CONFIDENCE IN EXACT
TIMING. FOG MAY DEVELOP AT THE TERMINAL THIS MORNING IF WINDS CALM.
ALSO COULD SEE FOG DEVELOP EARLIER THAN CURRENTLY FORECAST IN THE
TAF.
KBDL TERMINAL...HIGH CONFIDENCE IN TRENDS. LOWER CONFIDENCE IN
EXACT TIMING. DENSE FOG MAY BE SLOW TO LIFT THIS MORNING.
OUTLOOK /THURSDAY NIGHT THROUGH SUNDAY/...
FRIDAY...MODERATE CONFIDENCE. MAINLY VFR.
SATURDAY AND SUNDAY...LOW CONFIDENCE ON TIMING AND DETAILS.
EXPECT PERIODS OF MVFR/IFR IN SHOWERS AND PATCHY FOG. GUSTY SW
WINDS POSSIBLE SUNDAY.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
EASTERLY WINDS REMAIN LIGHT TODAY AND THEN GRADUALLY INCREASE AS
THEY SHIFT TO THE SOUTHWEST TONIGHT.. HOWEVER...THEY SHOULD
REMAIN BELOW 25 KTS UNTIL THURSDAY...WHEN THEY MAY GUST TO NEAR
25 KTS ON THE OUTER WATERS. PERSISTENT SOUTHERLY FLOW WILL LEAD TO
BUILDING SEAS THROUGHOUT THE PERIOD. SMALL CRAFT ADVISORIES ARE IN
PLACE FOR THE OUTER WATERS FOR SEAS AS WELL AS THE WIND GUSTS ON
THURSDAY.
OUTLOOK /THURSDAY NIGHT THROUGH SUNDAY/...
MODERATE OVERALL CONFIDENCE.
FRIDAY...WESTERLY WINDS BELOW 25 KT. ROUGH SEAS ACROSS THE OUTER
COASTAL WATERS SUBSIDING.
SATURDAY...MAINLY EASTERLY WINDS BELOW 25 KT. CHANCE OF LIGHT
RAIN WITH REDUCED VSBYS.
SUNDAY...GUSTY SW WINDS LIKELY REACHING 25-30 KT. LOW RISK WINDS
MAY REACH GALE FORCE.
&&
.CLIMATE...
RECORD HIGH MINIMUM TEMPERATURES FOR THURSDAY 12/24...
BOSTON 44/2003
PROVIDENCE 45/1941
HARTFORD 43/1931
WORCESTER 43/2003
RECORD HIGH TEMPERATURES FOR THURSDAY 12/24...
BOSTON 61/1996
PROVIDENCE64/2014
HARTFORD59/1996 AND 1990
WORCESTER57/1996 AND 1990
RECORD HIGH MINIMUM TEMPERATURES FOR FRIDAY 12/25...
BOSTON 44/2014
PROVIDENCE 46/1979
HARTFORD 43/2014
WORCESTER 47/1964
RECORD HIGH TEMPERATURES FOR FRIDAY 12/25...
BOSTON 65/1889
PROVIDENCE63/2014
HARTFORD64/1964
WORCESTER60/1964
RECORD HIGH TEMPERATURES FOR SUNDAY 12/27...
BOSTON 61/1949
PROVIDENCE59/1973
HARTFORD60/1949
WORCESTER 58/1895
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EST THURSDAY FOR ANZ235-237-
254>256.
SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 7 PM EST
THURSDAY FOR ANZ250.
SMALL CRAFT ADVISORY FROM 11 PM THIS EVENING TO 9 AM EST
THURSDAY FOR ANZ251.
&&
$$
SYNOPSIS...BELK/RLG
NEAR TERM...KJC/RLG
SHORT TERM...RLG
LONG TERM...BELK
AVIATION...KJC/BELK/RLG
MARINE...BELK/RLG
CLIMATE...
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
619 AM EST WED DEC 23 2015
.SYNOPSIS...
A WARM AND MOIST SOUTH FLOW WILL DOMINATE THROUGH MUCH OF THE WEEK
ASSOCIATED WITH OFFSHORE HIGH PRESSURE. NUMEROUS SHOWERS WILL
OCCUR TODAY AND TONIGHT WITH SOME DECREASE IN COVERAGE THURSDAY AS
UPPER RIDGING BECOMES A BIT MORE ESTABLISHED. VERY HEAVY RAIN MAY
OCCUR WITH SOME OF THE SHOWERS TODAY AND TONIGHT. MUCH ABOVE
NORMAL TEMPERATURES WILL CONTINUE.
&&
.NEAR TERM /THROUGH TONIGHT/...
HIGH LOW-LEVEL MOISTURE HAS RESULTED IN DENSE FOG OVER MUCH OF THE
FORECAST AREA. THE GFS LAMP MAINTAINS SIGNIFICANT FOG THROUGH
MUCH OF THE MORNING. WE HAVE POSTED A DENSE FOG ADVISORY.
MOISTURE WILL REMAIN VERY HIGH THROUGH TONIGHT ASSOCIATED
WITH THE SOUTHERLY FLOW FROM OFF THE ATLANTIC AND GULF PLUS
SOUTHWEST MID- LEVEL FLOW ORIGINATING FROM THE TROPICAL PACIFIC.
THE MODELS AND OBSERVATION TRENDS INDICATE PRECIPITABLE WATER NEAR
1.9 OF AN INCH. THE NAM AND GFS INDICATE THE H85 FLOW INCREASING
TODAY WITH SPEEDS THIS AFTERNOON AND TONIGHT OF 40 TO 50 KNOTS.
THE STRONG JET AND HIGH MOISTURE INDICATE POSSIBLE EXCESSIVE RAIN
AND A FLASH FLOOD WATCH HAS BEEN POSTED. THE HIGH-RESOLUTION
MODELS HAVE NOT BEEN CONSISTENT WITH THE TIMING OF GREATEST SHOWER
COVERAGE. THE 07Z HRRR DISPLAYED SCATTERED COVERAGE WITH SOME
INCREASE DURING THE AFTERNOON. RADAR TRENDS SUPPORT NUMEROUS
SHOWERS IN THE NEAR TERM. USED THE WPC GUIDANCE FOR THE GENERAL
RAINFALL FORECAST. THE STRONG SHEAR INDICATES A POSSIBILITY OF
SEVERE THUNDERSTORMS BUT THE THREAT APPEARS LIMITED BY A LACK OF
SIGNIFICANT SURFACE- BASED INSTABILITY BECAUSE OF CLOUD COVER AND
NUMEROUS SHOWERS. THE GFS LAMP AND NAM BUFKIT MOMENTUM TRANSFER
TOOL INDICATE WIND GUSTS OF 18 TO 25 KNOTS THIS AFTERNOON. LEANED
TOWARD THE LOWER VALUES BECAUSE OF EXPECTED CLOUDINESS AND LIMITED
MIXING. USED THE GUIDANCE CONSENSUS FOR THE TEMPERATURE FORECAST.
&&
.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
SURFACE HIGH PRESSURE OFF THE COAST WILL CONTINUE TO CIRCULATE A
MOIST SOUTH FLOW INTO THE FORECAST AREA THROUGH THURSDAY NIGHT
SUPPORTING SHOWERS. HOWEVER...THE MODELS HAVE BEEN CONSISTENT
INDICATING UPPER HEIGHTS BUILDING OVER THE FORECAST AREA FROM THE
SOUTHEAST. THE DIMINISHING UPPER SUPPORT SHOULD HELP DECREASE
SHOWER COVERAGE. THE NAM...GFS...AND ECMWF MOS INDICATE CHANCE
POPS. THE BUILDING UPPER RIDGE AND SOUTH FLOW WILL BRING MUCH
ABOVE NORMAL TEMPERATURES AND RECORDS FOR THE DATE MAY OCCUR. USED
THE GUIDANCE CONSENSUS FOR THE HIGH TEMPERATURE FORECAST WITH
EXPECTED LINGERING CLOUDINESS LIMITING HIGH TEMPERATURES. HIGH
LOW-LEVEL MOISTURE SHOULD RESULT IN WIDESPREAD STRATUS AND FOG
DURING THE EARLY MORNING HOURS.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
THE GFS AND ECMWF INDICATE UPPER RIDGING ESTABLISHED OVER THE
FORECAST AREA FRIDAY THROUGH SUNDAY. HOWEVER...THE WARM AND MOIST
SOUTH FLOW ASSOCIATED WITH OFFSHORE SURFACE HIGH PRESSURE SUPPORTS
POSSIBLE SHOWERS. THE GFS AND ECMWF MOS HAVE POPS OF 20 TO 30
PERCENT. THE MOS MAINTAINS MUCH ABOVE NORMAL TEMPERATURES.
THE MODELS INDICATE A WEAKENED UPPER RIDGE MONDAY AND TUESDAY. THE
MODELS HAVE NOT BEEN CONSISTENT WITH THE POSITION OF A FRONTAL
SYSTEM BUT DO GENERALLY INDICATE INCREASED MOISTURE. THE GFS AND
ECMWF MOS HAVE POPS OF 20 TO 50 PERCENT WITH CONTINUED ABOVE
NORMAL TEMPERATURES.
&&
.AVIATION /11Z WEDNESDAY THROUGH SUNDAY/...
WIDESPREAD PROLONGED IFR/LIFR CONDITIONS EXPECTED EARLY THIS
MORNING...WITH SOME IMPROVEMENT LATER TODAY.
IFR/LIFR CONDITIONS ACROSS THE AREA EARLY THIS MORNING. LATEST RADAR
MOSAIC INDICATING MAINLY LIGHT RAIN ACROSS THE AREA. OVERALL DO NOT
EXPECT MUCH IN THE WAY OF IMPROVEMENT BEFORE SUNRISE. SFC WRF MODEL
INDICATING ONE BAND OF PRECIPITATION MOVING THROUGH THE AREA LATER
THIS MORNING AND ANOTHER BAND MOVING THROUGH EARLY THIS
EVENING...BUT OTHER SHORT-TERM MODELS ARE SHOWING SOME DIFFERENCES.
AS A RESULT...CONSIDERABLE UNCERTAINTIES REMAIN WITH REGARDS TO
PLACEMENT...TIMING...AND INTENSITY OF PRECIPITATION. AT THIS
TIME...WILL HANDLE PRECIPITATION WITH VCSH. UNCERTAINTIES ALSO
REMAIN HOW MUCH CIGS/VSBYS WILL IMPROVE LATER TODAY. MODEL GUIDANCE
HINTING THAT CONDITIONS MAY IMPROVE TO MVFR LATER THIS AFTERNOON.
FOR NOW WILL LEAN TOWARDS HIGH-END IFR/MVFR THIS AFTERNOON.
CONDITIONS MAY DETERIORATE AGAIN TONIGHT BUT UNCERTAINTIES LINGER
DUE TO MODELS KEEPING SFC WINDS UP A BIT THIS EVENING INTO TONIGHT.
EXTENDED AVIATION OUTLOOK...CHANCE OF RAIN...AND MAINLY LATE NIGHT
AND MORNING RESTRICTIONS...LATE TONIGHT THROUGH MONDAY.
&&
.HYDROLOGY...
RIVER FLOOD WARNINGS HAVE BEEN POSTED FOR SOME OF THE RIVER
FORECAST POINTS. FLASH FLOOD WARNINGS MAY BE REQUIRED AT TIMES
THROUGH TONIGHT...MAINLY FOR SMALL STREAMS AND URBAN LOCATIONS.
&&
.CLIMATE...
HIGH TEMPERATURE RECORDS FOR CHRISTMAS EVE AND CHRISTMAS DAY.
COLUMBIA METRO AIRPORT (CAE)
DEC 24...76 SET IN 1964. FORECASTING 80.
DEC 25...79 SET IN 1955. FORECASTING 81.
AUGUSTA BUSH FIELD (AGS)
DEC 24...80 SET IN 1964. FORECASTING 80.
DEC 25...79 SET IN 1984. FORECASTING 81.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...DENSE FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR GAZ040-
063>065-077.
FLASH FLOOD WATCH THROUGH THURSDAY AFTERNOON FOR GAZ040-
063>065.
SC...DENSE FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR SCZ015-016-
018-020>022-025>031-035>038-041.
FLASH FLOOD WATCH THROUGH THURSDAY AFTERNOON FOR SCZ015-016-
018-020>022-025>028-030.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
614 AM EST WED DEC 23 2015
.SYNOPSIS...
A WARM AND MOIST SOUTH FLOW WILL DOMINATE THROUGH MUCH OF THE WEEK
ASSOCIATED WITH OFFSHORE HIGH PRESSURE. NUMEROUS SHOWERS WILL
OCCUR TODAY AND TONIGHT WITH SOME DECREASE IN COVERAGE THURSDAY AS
UPPER RIDGING BECOMES A BIT MORE ESTABLISHED. VERY HEAVY RAIN MAY
OCCUR WITH SOME OF THE SHOWERS TODAY AND TONIGHT. MUCH ABOVE
NORMAL TEMPERATURES WILL CONTINUE.
&&
.NEAR TERM /THROUGH TONIGHT/...
HIGH LOW-LEVEL MOISTURE HAS RESULTED IN DENSE FOG OVER MUCH OF THE
FORECAST AREA. THE GFS LAMP MAINTAINS SIGNIFICANT FOG THROUGH
MUCH OF THE MORNING. WE HAVE POSTED A DENSE FOG ADVISORY.
MOISTURE WILL REMAIN VERY HIGH THROUGH TONIGHT ASSOCIATED
WITH THE SOUTHERLY FLOW FROM OFF THE ATLANTIC AND GULF PLUS
SOUTHWEST MID- LEVEL FLOW ORIGINATING FROM THE TROPICAL PACIFIC.
THE MODELS AND OBSERVATION TRENDS INDICATE PRECIPITABLE WATER NEAR
1.9 OF AN INCH. THE NAM AND GFS INDICATE THE H85 FLOW INCREASING
TODAY WITH SPEEDS THIS AFTERNOON AND TONIGHT OF 40 TO 50 KNOTS.
THE STRONG JET AND HIGH MOISTURE INDICATE POSSIBLE EXCESSIVE RAIN
AND A FLASH FLOOD WATCH HAS BEEN POSTED. THE HIGH-RESOLUTION
MODELS HAVE NOT BEEN CONSISTENT WITH THE TIMING OF GREATEST SHOWER
COVERAGE. THE 07Z HRRR DISPLAYED SCATTERED COVERAGE WITH SOME
INCREASE DURING THE AFTERNOON. RADAR TRENDS SUPPORT NUMEROUS
SHOWERS IN THE NEAR TERM. USED THE WPC GUIDANCE FOR THE GENERAL
RAINFALL FORECAST. THE STRONG SHEAR INDICATES A POSSIBILITY OF
SEVERE THUNDERSTORMS BUT THE THREAT APPEARS LIMITED BY A LACK OF
SIGNIFICANT SURFACE- BASED INSTABILITY BECAUSE OF CLOUD COVER AND
NUMEROUS SHOWERS. THE GFS LAMP AND NAM BUFKIT MOMENTUM TRANSFER
TOOL INDICATE WIND GUSTS OF 18 TO 25 KNOTS THIS AFTERNOON. LEANED
TOWARD THE LOWER VALUES BECAUSE OF EXPECTED CLOUDINESS AND LIMITED
MIXING. USED THE GUIDANCE CONSENSUS FOR THE TEMPERATURE FORECAST.
&&
.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
SURFACE HIGH PRESSURE OFF THE COAST WILL CONTINUE TO CIRCULATE A
MOIST SOUTH FLOW INTO THE FORECAST AREA THROUGH THURSDAY NIGHT
SUPPORTING SHOWERS. HOWEVER...THE MODELS HAVE BEEN CONSISTENT
INDICATING UPPER HEIGHTS BUILDING OVER THE FORECAST AREA FROM THE
SOUTHEAST. THE DIMINISHING UPPER SUPPORT SHOULD HELP DECREASE
SHOWER COVERAGE. THE NAM...GFS...AND ECMWF MOS INDICATE CHANCE
POPS. THE BUILDING UPPER RIDGE AND SOUTH FLOW WILL BRING MUCH
ABOVE NORMAL TEMPERATURES AND RECORDS FOR THE DATE MAY OCCUR. USED
THE GUIDANCE CONSENSUS FOR THE HIGH TEMPERATURE FORECAST WITH
EXPECTED LINGERING CLOUDINESS LIMITING HIGH TEMPERATURES. HIGH
LOW-LEVEL MOISTURE SHOULD RESULT IN WIDESPREAD STRATUS AND FOG
DURING THE EARLY MORNING HOURS.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
THE GFS AND ECMWF INDICATE UPPER RIDGING ESTABLISHED OVER THE
FORECAST AREA FRIDAY THROUGH SUNDAY. HOWEVER...THE WARM AND MOIST
SOUTH FLOW ASSOCIATED WITH OFFSHORE SURFACE HIGH PRESSURE SUPPORTS
POSSIBLE SHOWERS. THE GFS AND ECMWF MOS HAVE POPS OF 20 TO 30
PERCENT. THE MOS MAINTAINS MUCH ABOVE NORMAL TEMPERATURES.
THE MODELS INDICATE A WEAKENED UPPER RIDGE MONDAY AND TUESDAY. THE
MODELS HAVE NOT BEEN CONSISTENT WITH THE POSITION OF A FRONTAL
SYSTEM BUT DO GENERALLY INDICATE INCREASED MOISTURE. THE GFS AND
ECMWF MOS HAVE POPS OF 20 TO 50 PERCENT WITH CONTINUED ABOVE
NORMAL TEMPERATURES.
&&
.AVIATION /11Z WEDNESDAY THROUGH SUNDAY/...
WIDESPREAD PROLONGED LIFR CONDITIONS EXPECTED EARLY THIS
MORNING...WITH CONDITIONS AT OR BELOW AIRPORT MINIMUMS POSSIBLE...
SOME IMPROVEMENT LATER TODAY.
IFR/LIFR CONDITIONS ACROSS THE AREA EARLY THIS MORNING. LATEST RADAR
MOSAIC INDICATING MAINLY LIGHT RAIN ACROSS THE AREA. OVERALL DO NOT
EXPECT MUCH IN THE WAY OF IMPROVEMENT BEFORE SUNRISE. SFC WRF MODEL
INDICATING ONE BAND OF PRECIPITATION MOVING THROUGH THE AREA LATER
THIS MORNING AND ANOTHER BAND MOVING THROUGH EARLY THIS
EVENING...BUT OTHER SHORT-TERM MODELS ARE SHOWING SOME DIFFERENCES.
AS A RESULT...CONSIDERABLE UNCERTAINTIES REMAIN WITH REGARDS TO
PLACEMENT...TIMING...AND INTENSITY OF PRECIPITATION. AT THIS
TIME...WILL HANDLE PRECIPITATION WITH VCSH. UNCERTAINTIES ALSO
REMAIN HOW MUCH CIGS/VSBYS WILL IMPROVE LATER TODAY. MODEL GUIDANCE
HINTING THAT CONDITIONS MAY IMPROVE TO MVFR LATER THIS AFTERNOON.
FOR NOW WILL LEAN TOWARDS HIGH-END IFR/MVFR THIS AFTERNOON.
CONDITIONS MAY DETERIORATE AGAIN TONIGHT BUT UNCERTAINTIES LINGER
DUE TO MODELS KEEPING SFC WINDS UP A BIT THIS EVENING INTO TONIGHT.
EXTENDED AVIATION OUTLOOK...CHANCE OF RAIN...AND MAINLY LATE NIGHT
AND MORNING RESTRICTIONS...LATE TONIGHT THROUGH MONDAY.
&&
.HYDROLOGY...
RIVER FLOOD WARNINGS HAVE BEEN POSTED FOR SOME OF THE RIVER
FORECAST POINTS. FLASH FLOOD WARNINGS MAY BE REQUIRED AT TIMES
THROUGH TONIGHT...MAINLY FOR SMALL STREAMS AND URBAN LOCATIONS.
&&
.CLIMATE...
HIGH TEMPERATURE RECORDS FOR CHRISTMAS EVE AND CHRISTMAS DAY.
COLUMBIA METRO AIRPORT (CAE)
DEC 24...76 SET IN 1964. FORECASTING 80.
DEC 25...79 SET IN 1955. FORECASTING 81.
AUGUSTA BUSH FIELD (AGS)
DEC 24...80 SET IN 1964. FORECASTING 80.
DEC 25...79 SET IN 1984. FORECASTING 81.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...DENSE FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR GAZ040-
063>065-077.
FLASH FLOOD WATCH THROUGH THURSDAY AFTERNOON FOR GAZ040-
063>065.
SC...DENSE FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR SCZ015-016-
018-020>022-025>031-035>038-041.
FLASH FLOOD WATCH THROUGH THURSDAY AFTERNOON FOR SCZ015-016-
018-020>022-025>028-030.
&&
$$
AREA FORECAST DISCUSSION
National Weather Service Lincoln IL
551 AM CST WED DEC 23 2015
.SHORT TERM...(Today)
ISSUED AT 330 AM CST WED DEC 23 2015
09z/3am surface analysis shows a 986mb low over south-central Kansas
with a warm front extending eastward across Missouri into southern
Illinois. Southerly flow to the south of the front has resulted in
temperatures steadily rising into the lower 60s across Kentucky and
far southern Illinois...and well into the 50s further north across
the KILX CWA. Due to low-level warm/moist advection, widespread fog
has developed along/east of a Bloomington to Taylorville line. Do
not think dense fog will be an issue however, as surface winds have
been strong enough to provide enough mixing of the atmosphere to
keep vsbys around 1 mile at the lowest. HRRR shows the fog
persisting through early morning before gradually dissipating and
pushing further north.
Current water vapor imagery shows vigorous short-wave trough
tracking across the Oklahoma/Texas panhandles, and this feature is
already triggering widespread convection across eastern Oklahoma
into Arkansas. 4km WRF-NMM has a very good handle on the convection
and shows it tracking northeastward into central Illinois after
13/14z. Based on this forecast and current radar trends, have gone
with categorical PoPs for showers/thunder this morning. This
initial surge of convection will lift into northern Illinois toward
midday, resulting in a lull in the precip across the KILX CWA by
early afternoon. May even see a few breaks in the overcast as per
the HRRR cloud height forecast. Big question then becomes how much
convection will develop along an advancing cold front late this
afternoon into the evening. Several models suggest much of central
Illinois may only see scattered thunderstorms, with the more
concentrated area of convection further south from the I-70 corridor
southward into the Tennessee River Valley. Given robust instability
characterized by SBCAPEs of 500-1000J/kg and strong 0-6km bulk shear
of 70-80kt, have continued with categorical PoPs along/ahead of the
front this afternoon. Have also mentioned severe, as latest Day 1
outlook from SPC now places the entire area under a Slight Risk.
Aside from the storm chances, this will be a windy and extremely
warm day. Southerly winds will gust to between 35 and 40 mph,
helping push temperatures to near record levels in the middle to
upper 60s. In fact, if a few breaks do indeed develop in the
overcast, would not be surprised to see temps rise into the lower
70s in a few spots.
.LONG TERM...(Tonight through Tuesday)
ISSUED AT 330 AM CST WED DEC 23 2015
As deep low pressure tracks from eastern Iowa this evening to Lake
Superior by midnight, impressive pressure rises will create very
strong southwesterly winds across the area this evening behind the
departing cold front. A Wind Advisory may need to be issued for
areas north of the I-70 corridor, as gusts could exceed 40 mph. Will
hold off on the advisory for now, waiting until the strong to
potentially severe convection clears the area later today.
Showers/storms will quickly exit into Indiana by midnight, with dry
weather expected overnight.
A lull in the action is still anticipated for Thursday into Friday,
with slightly cooler high temperatures in the 40s and 50s. After
that, a wet/unsettled weekend is on tap. 00z Dec 23 models are in
relatively good agreement concerning the heavy rain set-up
initially, with both the GFS and ECMWF showing widespread showers
and even a few thunderstorms for Saturday/Saturday night. Latest
GFS is beginning to look more like previous runs of the ECMWF, which
shows a northern stream short-wave pushing the main baroclinic zone
southward into the Ohio River Valley on Sunday. In fact, the latest
ECMWF now shows the front south of the Ohio River and features dry
weather across central Illinois Sunday afternoon and night. Am not
ready to go quite that far yet, although the southward trend is
definitely there. Have therefore lowered PoPs substantially across
the northern half of the CWA Sunday/Sunday night and have pushed
thunder mention further south out of the area. Closed upper low
over the Desert Southwest will eventually eject northeastward,
bringing higher PoPs back by Monday/Monday night. Rain chances will
then finally decrease by Tuesday as the low lifts into the Great
Lakes.
&&
.AVIATION...(For the 12Z TAFS through 12Z Thursday morning)
ISSUED AT 545 AM CST WED DEC 23 2015
IFR or lower conditions will start at all TAF sites as low stratus
blankets the area at start of TAF period. Cigs are forecast to
remain IFR through the morning and into the afternoon at all
sites. Except for BMI all TAF sites have MVFR vis or better. BMI
still has 1/4sm FG, but thinking is this will gradually improve
this morning. The first batch of showers and isolated
thunderstorms will begin to move through, effecting the TAF sites
starting at 14z at PIA and SPI, and then 15z at DEC/BMI/CMI. These
conditions will continue through the late morning. Then by
afternoon, the second wave of pcpn will begin to move toward the
area and effect the TAFs. Unsure on timing, but going with 19z at
SPI and PIA, and then 20z at DEC/CMI/BMI. Will also have VCTS
since also unsure if pcpn will actually effect on station. Once
this moves through late afternoon to early evening, conditions
will improve at all sites, and then become clear after midnight.
Southeast winds will become southerly and begin to gust to near
30kts. Southerly winds will increase during the morning and into
the afternoon hours with gusts to around 35kts or little higher at
BMI and CMI. When the winds become more southwesterly after the
second wave of pcpn, wind speeds will become higher with all sites
gusting to between 37 and 38kts. Winds will decrease overnight
and become more westerly.
&&
.CLIMATE...
ISSUED AT 458 AM CST WED DEC 23 2015
Record highs for today:
Bloomington/Normal......... 63 in 1933
Champaign/Urbana........... 64 in 1933
Charleston/Mattoon......... 69 in 1933
Danville................... 65 in 1933
Decatur.................... 66 in 1933
Effingham.................. 68 in 1933
Jacksonville............... 70 in 1933
Lincoln.................... 65 in 1933
Olney...................... 67 in 1931
Peoria..................... 65 in 1933
Springfield................ 66 in 1933
&&
.ILX Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...Barnes
LONG TERM...Barnes
AVIATION...Auten
CLIMATE...Barnes
AREA FORECAST DISCUSSION
NWS DES MOINES IA
543 AM CST WED DEC 23 2015
.SHORT TERM /TODAY/...
ISSUED AT 410 AM CST WED DEC 23 2015
MORNING WATER VAPOR IMAGERY DEPICTS A SEASONABLY STRONG NEGATIVELY
TILTED LONGWAVE TROUGH AXIS SITUATED DOWN THE EASTERN FLANK OF THE
ROCKIES WITH A 150 KT JET IMPINGING ALONG ITS SOUTHWEST FLANK. AN
EMBEDDED SHORTWAVE/PV ANOMALY WILL EJECT NORTHEASTWARD FROM THE BASE
OF THE TROUGH TO THE SOUTHERN MISSOURI RIVER VALLEY BY 00Z THIS
EVENING. A DEEPENING 986 MB SURFACE CYCLONE OVER THE OKLAHOMA
PANHANDLE WILL LIKEWISE LIFT NORTHEASTWARD OVER THE COURSE OF THE
DAY AND BE SITUATED NEAR PRAIRIE DU CHIEN BY 00Z TONIGHT USING THE
GFS SOLUTION...WHICH IS HANDLING THE DEEPENING EVOLUTION OF THE LOW
THE BEST THIS MORNING. THIS WILL BRING A WIDE VARIETY OF WEATHER
ACROSS CENTRAL IOWA TODAY.
STARTING OUT THIS MORNING...A BROAD WARM FRONT CURRENTLY STRETCHES
FROM NEAR OMAHA TO DUBUQUE...WITH TEMPERATURES IN THE MID 30S NORTH
OF THE BOUNDARY TO MID 40S SOUTH. THIS BOUNDARY WILL TIGHTEN DURING
THE COURSE OF THE DAY AS THE LOW APPROACHES...WITH HIGHS RANGING
FROM THE MID 30S NORTHWEST TO NEAR 60 IN THE SOUTHEAST. AS THE LOW
BEGINS TO PULL EASTWARD AFTER 18Z...THIS WILL LIKEWISE PULL THE
BOUNDARY EASTWARD AS A COLD FRONT THIS AFTERNOON AND EVENING.
WIDESPREAD RAIN IS EXPANDING ACROSS THE AREA NOW AS STRONG MIDLEVEL
KINEMATIC/290-300 K ISENTROPIC FORCING INTENSIFIES. INITIAL BOUT OF
PRECIP EARLIER IN THE NIGHT TIED IN WITH A REGION OF THETA-E
ADVECTION HAD TO FIGHT A SUB 800 MB DRY LAYER...BUT THE COLUMN IS
RAPIDLY SATURATING AND PRECIP IS BEING REPORTED AT MULTIPLE SITES.
BEST MIDLEVEL FORCING AND DEEPEST MOISTURE WILL BE COINCIDENT IN THE
15-21Z TIMEFRAME AND HAVE KEPT THE MAX QPF AMOUNTS DURING THIS
WINDOW. PWATS OF 0.50 TO 0.75 INCHES ARE 2 TO 3 STANDARD DEVIATIONS
ABOVE NORMAL AND DAILY TOTAL RAINFALL AMOUNTS OF 0.50 TO 0.75 INCHES
ARE POSSIBLE. THIS WIDESPREAD RAIN WILL LEAD TO RISES IN AREA RIVERS
WHICH HAVE STILL NOT FULLY RECOVERED FROM THE RECORD SETTING DELUGE
A WEEK AND A HALF AGO.
AS THE UPPER LEVEL WAVE MATURES A DRY SLOT WILL WRAP NORTHWARD
ACROSS THE SOUTHERN AND EASTERN PORTIONS OF THE STATE BETWEEN 18 AND
00Z. CURRENT POP AND QPF GRIDS MAY BE A LITTLE CONSERVATIVE ON THE
TIMING OF THIS DRY SLOT OVER SOUTHERN IOWA...BUT GIVEN THE SLOWER
TRENDS OF RECENT MODEL RUNS...HAVE KEPT CATEGORICAL POPS OVER THE
SOUTH UNTIL 16-17Z. THIS DRY SLOT WILL ALSO RESULT IN STEEPENING MID
LEVEL LAPSE RATES AND INCREASING INSTABILITY OVER THE SOUTHEASTERN
PORTION OF THE CWA. RAP BUFR SOUNDINGS FROM OTTUMWA SHOW 300-500
J/KG OF MUCAPE DEVELOPING BETWEEN 18-20Z. 0-6 KM SHEAR VALUES OF 40
TO 50 KTS WILL BE MORE THAN CAPABLE OF MAINTAINING ANY THUNDERSTORMS
THAT DO DEVELOP IN THE WARM SECTOR EARLY THIS AFTERNOON. THE THREAT
FOR ORGANIZED AND SEVERE CONVECTION WILL BE CONFINED TO A VERY
NARROW AND CONDITIONAL WINDOW ACROSS THE FAR SOUTHEAST...AND WITH
STORM MOTIONS OF 40 TO 50 KTS TO THE NORTHEAST...THESE STORMS WILL
RAPIDLY EXIT THE CWA. THE MAIN THREAT WOULD BE LARGE HAIL GIVEN THE
LOW FREEZING LEVELS...BUT IF SOMEHOW ANY SOLAR INSOLATION WERE TO
TAKE PLACE AND THE STORMS DID GO SURFACE BASED...THE 35 KTS OF 0-1
KM SHEAR AND PROXIMITY TO THE SURFACE LOW WOULD SUPPORT TORNADOES.
AGAIN...THE THREAT FOR ANY SEVERE WEATHER...LET ALONE TORNADOES...IS
VERY CONDITIONAL AND LIMITED TO A SHORT WINDOW FROM AROUND 19-22Z.
NEXT ON THE DOCKET ARE WINDS ON THE BACKSIDE OF THE LOW. A
TIGHTENING PRESSURE GRADIENT AND STRONG PRESSURE RISE COUPLET
IMMEDIATELY FOLLOWING THE LOW WILL RESULT IN WINDS OF 20 TO 25 KTS
SUSTAINED WITH GUSTS OF 30 TO 35 KTS ACROSS SOUTHERN IOWA THROUGH
THE LATE AFTERNOON AND EVENING HOURS. DEFORMATION ZONE AND ELEVATED
FG ZONE WILL LINGER ACROSS THE WESTERN PORTIONS OF THE CWA AS THE
FRONTAL BOUNDARY SLIDES EASTWARD. PRECIP IN THIS ZONE WILL CHANGE
OVER TO SNOW DURING THE COURSE OF THE AFTERNOON AS COOLER AIR MOVES
IN...BUT KEPT SNOW AMOUNTS AROUND A HALF INCH OR LESS GIVEN THE LACK
OF ANY STRONG CAA AND NEAR SURFACE TEMPS STILL IN THE LOW TO MID
30S. ROADS WILL LIKELY JUST STAY WET WITH ACCUMULATIONS ON GRASSY
AREAS.
.LONG TERM /TONIGHT THROUGH TUESDAY/...
ISSUED AT 410 AM CST WED DEC 23 2015
THE PATTERN WILL BE QUITE ACTIVE THROUGH THE ENTIRE PERIOD...WITH
SOME TRAVEL IMPACTS EXPECTED DURING THE EXTENDED...BUT CONFIDENCE
IN DETAILS REMAINS LOW FOR A MULTITUDE OF REASONS. AT ONSET EXPECT
A FRONTOGENETICALLY FORCED DEFORMATION ZONE WITH DEEP VERTICAL
MOTION TO BE QUICKLY RETREATING TO THE NORTH AND EAST EARLY IN THE
EVENING. CONFIDENCE IN SNOW ACCUMS HAS INCREASED...AND DENDRITIC
GROWTH ZONE LIFT WILL BE QUITE STRONG FOR A PERIOD...BUT IT WILL
BE VERY BRIEF AND TRANSIENT. TOTAL ACCUMS WILL GENERALLY BE AN
INCH OR LESS NORTH AND WEST...BUT TOTALS MAY VARY A BIT IN EITHER
DIRECTION DUE TO MELTING ON PAVEMENT VS VEGETATION AND LOCALIZED
HIGHER RATES. ANYTHING TOWARD THE INCH RANGE WOULD BE FAR NORTH.
STRONG SUBSIDENCE WILL THEN SET IN BY NIGHT. MIXING WILL BE FAIRLY
SHALLOW BUT MSLP GRADIENT MAY STILL ALLOW FOR GUSTS TO REACH 35
MPH OR SO THROUGH AT LEAST MIDNIGHT NE.
SHORT WAVE RIDING STRONG NRN CA/OR JET WILL THEN REACH THE MO VALLEY
THU. FORCING AND MOISTURE EXTENT WILL BE QUITE VARIABLE...NEVER
REALLY APPROACHING SATURATION. THIS WILL RESULT IN ANY AMOUNTS
BEING QUITE LIGHT...AND PTYPE IN QUESTION DUE TO ONLY A SMALL
WINDOW OF ICE INTRODUCTION. THUS HAVE LOW CHANCES WITH BOTH LIGHT
SNOW OR FLURRIES...AND LIGHT FREEZING RAIN/SPRINKLES POSSIBLE.
SHOULD SEE A BRIEF BREAK IN PRECIP THU NIGHT BEFORE SHORT WAVES
REACH CA AND CONTINUE TO CARVE OUT WRN CONUS LONG WAVE TROUGH...AND
EVENTUAL CUTOFF. THIS SETS UP A PROLONGED PERIOD OF SWLY FLOW
ALOFT...AND INVERTED TROUGHINESS INTO THE MID MS VALLEY. AS THE
CLOSED LOW FORMS IN THE SW...A SHORT WAVE WILL SPLIT AND RIDE THE SW
FLOW INTO THE MO VALLEY EARLY IN THE WEEKEND. PRECIP CHANCES WILL
INCREASE SHARPLY FRI INTO FRI NIGHT. ALTHOUGH THE DEEPEST QG FORCING
WILL REMAIN JUST TO OUR NORTH AND WEST...THE H85/H7 FORCING IS
EXTREME WITH HIGH CONTRIBUTIONS FROM THETA-E ADVECTION AND
FRONTOGENESIS. SNOWFALL RATES OVER NRN IA MAY BRIEFLY BE QUITE HIGH
WITH LOW STABILITY. GFS TICKS OFF SOME MUCAPES AND...ALTHOUGH
FAIRLY ELEVATED...ALSO SHOWS NEGATIVE SAT EPV WHICH WOULD BE
EXPECTED WITH THE LOW STATIC STABILITY AND MUCAPE REFLECTION. THUS
HAVE AN INCH OR TWO OF SNOW ACCUMS POSSIBLE NORTH THROUGH 12Z SAT
WITH ADDITIONAL AMOUNTS POSSIBLE AFTER THAT TIME. THE WAVE THEN
MOVES AWAY LATER SAT WITH THE ATTENTION TURNING TOWARD THE
APPROACHING CUTOFF LOW. SOME POPS LINGER THROUGH THE
WEEKEND...ESPECIALLY SOUTH...BUT NEITHER THE FORCING OR MOISTURE
IS TOO IMPRESSIVE.
THE PROGRESSION OF THE CUTOFF LOW WILL LIKELY RESULT IN THE BIGGEST
TRAVEL IMPACT OF THE HOLIDAY TRAVEL SEASON...BUT DETAILS ARE FAR
FROM CLEAR CUT. THE ECMWF HAS BEEN FAIRLY CONSISTENT WITH ITS
FARTHER WEST AND LESS SNOWY TRACK...BUT VARIABLE IN TIME OVER
RECENT RUNS. THE GFS TRACK AND TIMING HAVE BEEN MORE
CONSISTENT...AND POINT TOWARD A WIND BLOW HEAVY SNOW EVENT...BUT
IS A FASTER OUTLIER VS THE SLOWER CANADIAN AND ECMWF. RATHER THAN
FOCUSING ON THE DETAILS THE MAIN TAKE HOME POINT FOR NOW WOULD
APPEAR TO BE A SIGNIFICANT SYSTEM WILL AFFECT HOLIDAY TRAVEL IN OR
NEAR IA SOMETIME AROUND MON OR MON NIGHT. FOR THE TIME BEING HAVE
EITHER RAIN OR SNOW IN THE FORECAST WITH LOW CONFIDENCE...BUT THE
ECMWF ALSO HINTS AT THE POSSIBILITY OF A FREEZING RAIN/ICING EVENT
NRN HALF WITH A NICE ELEVATED WARM LAYER ABOVE SUB FREEZING
SURFACE TEMPS AND A BRISK ELY WIND. WILL NEED TO CONTINUE TO
MONITOR FOR THE POTENTIAL FOR EITHER ICING OR SNOW. WHATEVER
OCCURS LOOKS TO BE GONE BY TUE NIGHT EVEN WITH THE SLOWER ECMWF
SOLUTION.
&&
.AVIATION...23/12Z
ISSUED AT 540 AM CST WED DEC 23 2015
RAIN WILL CONTINUE ACROSS THE AREA THIS MORNING WITH CIGS AND
VSBYS FALLING TO IFR/LIFR LEVELS BY MID MORNING IN MOST
LOCATIONS. THUNDERSTORMS WILL ALSO BE POSSIBLE IN SOUTHEAST IOWA
DURING THE EARLY TO MID AFTERNOON HOURS. THE RAIN WILL TRANSITION
TO SNOW FOR A SHORT TIME ON THE BACKSIDE OF THE SYSTEM BEFORE
ENDING WITH CIGS GRADUALLY IMPROVING. HOWEVER...NORTHWESTERLY
WINDS WILL INCREASE TO 20 TO 25 KTS WITH GUSTS OVER 30 KTS THIS
EVENING AND INTO THE OVERNIGHT HOURS.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...SKOW
LONG TERM...SMALL
AVIATION...SKOW
AREA FORECAST DISCUSSION
NWS DES MOINES IA
445 AM CST WED DEC 23 2015
.SHORT TERM /TODAY/...
ISSUED AT 410 AM CST WED DEC 23 2015
MORNING WATER VAPOR IMAGERY DEPICTS A SEASONABLY STRONG NEGATIVELY
TILTED LONGWAVE TROUGH AXIS SITUATED DOWN THE EASTERN FLANK OF THE
ROCKIES WITH A 150 KT JET IMPINGING ALONG ITS SOUTHWEST FLANK. AN
EMBEDDED SHORTWAVE/PV ANOMALY WILL EJECT NORTHEASTWARD FROM THE BASE
OF THE TROUGH TO THE SOUTHERN MISSOURI RIVER VALLEY BY 00Z THIS
EVENING. A DEEPENING 986 MB SURFACE CYCLONE OVER THE OKLAHOMA
PANHANDLE WILL LIKEWISE LIFT NORTHEASTWARD OVER THE COURSE OF THE
DAY AND BE SITUATED NEAR PRAIRIE DU CHIEN BY 00Z TONIGHT USING THE
GFS SOLUTION...WHICH IS HANDLING THE DEEPENING EVOLUTION OF THE LOW
THE BEST THIS MORNING. THIS WILL BRING A WIDE VARIETY OF WEATHER
ACROSS CENTRAL IOWA TODAY.
STARTING OUT THIS MORNING...A BROAD WARM FRONT CURRENTLY STRETCHES
FROM NEAR OMAHA TO DUBUQUE...WITH TEMPERATURES IN THE MID 30S NORTH
OF THE BOUNDARY TO MID 40S SOUTH. THIS BOUNDARY WILL TIGHTEN DURING
THE COURSE OF THE DAY AS THE LOW APPROACHES...WITH HIGHS RANGING
FROM THE MID 30S NORTHWEST TO NEAR 60 IN THE SOUTHEAST. AS THE LOW
BEGINS TO PULL EASTWARD AFTER 18Z...THIS WILL LIKEWISE PULL THE
BOUNDARY EASTWARD AS A COLD FRONT THIS AFTERNOON AND EVENING.
WIDESPREAD RAIN IS EXPANDING ACROSS THE AREA NOW AS STRONG MIDLEVEL
KINEMATIC/290-300 K ISENTROPIC FORCING INTENSIFIES. INITIAL BOUT OF
PRECIP EARLIER IN THE NIGHT TIED IN WITH A REGION OF THETA-E
ADVECTION HAD TO FIGHT A SUB 800 MB DRY LAYER...BUT THE COLUMN IS
RAPIDLY SATURATING AND PRECIP IS BEING REPORTED AT MULTIPLE SITES.
BEST MIDLEVEL FORCING AND DEEPEST MOISTURE WILL BE COINCIDENT IN THE
15-21Z TIMEFRAME AND HAVE KEPT THE MAX QPF AMOUNTS DURING THIS
WINDOW. PWATS OF 0.50 TO 0.75 INCHES ARE 2 TO 3 STANDARD DEVIATIONS
ABOVE NORMAL AND DAILY TOTAL RAINFALL AMOUNTS OF 0.50 TO 0.75 INCHES
ARE POSSIBLE. THIS WIDESPREAD RAIN WILL LEAD TO RISES IN AREA RIVERS
WHICH HAVE STILL NOT FULLY RECOVERED FROM THE RECORD SETTING DELUGE
A WEEK AND A HALF AGO.
AS THE UPPER LEVEL WAVE MATURES A DRY SLOT WILL WRAP NORTHWARD
ACROSS THE SOUTHERN AND EASTERN PORTIONS OF THE STATE BETWEEN 18 AND
00Z. CURRENT POP AND QPF GRIDS MAY BE A LITTLE CONSERVATIVE ON THE
TIMING OF THIS DRY SLOT OVER SOUTHERN IOWA...BUT GIVEN THE SLOWER
TRENDS OF RECENT MODEL RUNS...HAVE KEPT CATEGORICAL POPS OVER THE
SOUTH UNTIL 16-17Z. THIS DRY SLOT WILL ALSO RESULT IN STEEPENING MID
LEVEL LAPSE RATES AND INCREASING INSTABILITY OVER THE SOUTHEASTERN
PORTION OF THE CWA. RAP BUFR SOUNDINGS FROM OTTUMWA SHOW 300-500
J/KG OF MUCAPE DEVELOPING BETWEEN 18-20Z. 0-6 KM SHEAR VALUES OF 40
TO 50 KTS WILL BE MORE THAN CAPABLE OF MAINTAINING ANY THUNDERSTORMS
THAT DO DEVELOP IN THE WARM SECTOR EARLY THIS AFTERNOON. THE THREAT
FOR ORGANIZED AND SEVERE CONVECTION WILL BE CONFINED TO A VERY
NARROW AND CONDITIONAL WINDOW ACROSS THE FAR SOUTHEAST...AND WITH
STORM MOTIONS OF 40 TO 50 KTS TO THE NORTHEAST...THESE STORMS WILL
RAPIDLY EXIT THE CWA. THE MAIN THREAT WOULD BE LARGE HAIL GIVEN THE
LOW FREEZING LEVELS...BUT IF SOMEHOW ANY SOLAR INSOLATION WERE TO
TAKE PLACE AND THE STORMS DID GO SURFACE BASED...THE 35 KTS OF 0-1
KM SHEAR AND PROXIMITY TO THE SURFACE LOW WOULD SUPPORT TORNADOES.
AGAIN...THE THREAT FOR ANY SEVERE WEATHER...LET ALONE TORNADOES...IS
VERY CONDITIONAL AND LIMITED TO A SHORT WINDOW FROM AROUND 19-22Z.
NEXT ON THE DOCKET ARE WINDS ON THE BACKSIDE OF THE LOW. A
TIGHTENING PRESSURE GRADIENT AND STRONG PRESSURE RISE COUPLET
IMMEDIATELY FOLLOWING THE LOW WILL RESULT IN WINDS OF 20 TO 25 KTS
SUSTAINED WITH GUSTS OF 30 TO 35 KTS ACROSS SOUTHERN IOWA THROUGH
THE LATE AFTERNOON AND EVENING HOURS. DEFORMATION ZONE AND ELEVATED
FG ZONE WILL LINGER ACROSS THE WESTERN PORTIONS OF THE CWA AS THE
FRONTAL BOUNDARY SLIDES EASTWARD. PRECIP IN THIS ZONE WILL CHANGE
OVER TO SNOW DURING THE COURSE OF THE AFTERNOON AS COOLER AIR MOVES
IN...BUT KEPT SNOW AMOUNTS AROUND A HALF INCH OR LESS GIVEN THE LACK
OF ANY STRONG CAA AND NEAR SURFACE TEMPS STILL IN THE LOW TO MID
30S. ROADS WILL LIKELY JUST STAY WET WITH ACCUMULATIONS ON GRASSY
AREAS.
.LONG TERM /TONIGHT THROUGH TUESDAY/...
ISSUED AT 410 AM CST WED DEC 23 2015
THE PATTERN WILL BE QUITE ACTIVE THROUGH THE ENTIRE PERIOD...WITH
SOME TRAVEL IMPACTS EXPECTED DURING THE EXTENDED...BUT CONFIDENCE
IN DETAILS REMAINS LOW FOR A MULTITUDE OF REASONS. AT ONSET EXPECT
A FRONTOGENETICALLY FORCED DEFORMATION ZONE WITH DEEP VERTICAL
MOTION TO BE QUICKLY RETREATING TO THE NORTH AND EAST EARLY IN THE
EVENING. CONFIDENCE IN SNOW ACCUMS HAS INCREASED...AND DENDRITIC
GROWTH ZONE LIFT WILL BE QUITE STRONG FOR A PERIOD...BUT IT WILL
BE VERY BRIEF AND TRANSIENT. TOTAL ACCUMS WILL GENERALLY BE AN
INCH OR LESS NORTH AND WEST...BUT TOTALS MAY VARY A BIT IN EITHER
DIRECTION DUE TO MELTING ON PAVEMENT VS VEGETATION AND LOCALIZED
HIGHER RATES. ANYTHING TOWARD THE INCH RANGE WOULD BE FAR NORTH.
STRONG SUBSIDENCE WILL THEN SET IN BY NIGHT. MIXING WILL BE FAIRLY
SHALLOW BUT MSLP GRADIENT MAY STILL ALLOW FOR GUSTS TO REACH 35
MPH OR SO THROUGH AT LEAST MIDNIGHT NE.
SHORT WAVE RIDING STRONG NRN CA/OR JET WILL THEN REACH THE MO VALLEY
THU. FORCING AND MOISTURE EXTENT WILL BE QUITE VARIABLE...NEVER
REALLY APPROACHING SATURATION. THIS WILL RESULT IN ANY AMOUNTS
BEING QUITE LIGHT...AND PTYPE IN QUESTION DUE TO ONLY A SMALL
WINDOW OF ICE INTRODUCTION. THUS HAVE LOW CHANCES WITH BOTH LIGHT
SNOW OR FLURRIES...AND LIGHT FREEZING RAIN/SPRINKLES POSSIBLE.
SHOULD SEE A BRIEF BREAK IN PRECIP THU NIGHT BEFORE SHORT WAVES
REACH CA AND CONTINUE TO CARVE OUT WRN CONUS LONG WAVE TROUGH...AND
EVENTUAL CUTOFF. THIS SETS UP A PROLONGED PERIOD OF SWLY FLOW
ALOFT...AND INVERTED TROUGHINESS INTO THE MID MS VALLEY. AS THE
CLOSED LOW FORMS IN THE SW...A SHORT WAVE WILL SPLIT AND RIDE THE SW
FLOW INTO THE MO VALLEY EARLY IN THE WEEKEND. PRECIP CHANCES WILL
INCREASE SHARPLY FRI INTO FRI NIGHT. ALTHOUGH THE DEEPEST QG FORCING
WILL REMAIN JUST TO OUR NORTH AND WEST...THE H85/H7 FORCING IS
EXTREME WITH HIGH CONTRIBUTIONS FROM THETA-E ADVECTION AND
FRONTOGENESIS. SNOWFALL RATES OVER NRN IA MAY BRIEFLY BE QUITE HIGH
WITH LOW STABILITY. GFS TICKS OFF SOME MUCAPES AND...ALTHOUGH
FAIRLY ELEVATED...ALSO SHOWS NEGATIVE SAT EPV WHICH WOULD BE
EXPECTED WITH THE LOW STATIC STABILITY AND MUCAPE REFLECTION. THUS
HAVE AN INCH OR TWO OF SNOW ACCUMS POSSIBLE NORTH THROUGH 12Z SAT
WITH ADDITIONAL AMOUNTS POSSIBLE AFTER THAT TIME. THE WAVE THEN
MOVES AWAY LATER SAT WITH THE ATTENTION TURNING TOWARD THE
APPROACHING CUTOFF LOW. SOME POPS LINGER THROUGH THE
WEEKEND...ESPECIALLY SOUTH...BUT NEITHER THE FIC/290-300 K
ISENTROPIC FORCING OR MOISTURE IS TOO IMPRESSIVE.
THE PROGRESSION OF THE CUTOFF LOW WILL LIKELY RESULT IN THE BIGGEST
TRAVEL IMPACT OF THE HOLIDAY TRAVEL SEASON...BUT DETAILS ARE FAR
FROM CLEAR CUT. THE ECMWF HAS BEEN FAIRLY CONSISTENT WITH ITS
FARTHER WEST AND LESS SNOWY TRACK...BUT VARIABLE IN TIME OVER
RECENT RUNS. THE GFS TRACK AND TIMING HAVE BEEN MORE
CONSISTENT...AND POINT TOWARD A WIND BLOW HEAVY SNOW EVENT...BUT
IS A FASTER OUTLIER VS THE SLOWER CANADIAN AND ECMWF. RATHER THAN
FOCUSING ON THE DETAILS THE MAIN TAKE HOME POINT FOR NOW WOULD
APPEAR TO BE A SIGNIFICANT SYSTEM WILL AFFECT HOLIDAY TRAVEL IN OR
NEAR IA SOMETIME AROUND MON OR MON NIGHT. FOR THE TIME BEING HAVE
EITHER RAIN OR SNOW IN THE FORECAST WITH LOW CONFIDENCE...BUT THE
ECMWF ALSO HINTS AT THE POSSIBILITY OF A FREEZING RAIN/ICING EVENT
NRN HALF WITH A NICE ELEVATED WARM LAYER ABOVE SUB FREEZING
SURFACE TEMPS AND A BRISK ELY WIND. WILL NEED TO CONTINUE TO
MONITOR FOR THE POTENTIAL FOR EITHER ICING OR SNOW. WHATEVER
OCCURS LOOKS TO BE GONE BY TUE NIGHT EVEN WITH THE SLOWER ECMWF
SOLUTION.
&&
.AVIATION...23/06Z
ISSUED AT 1126 PM CST TUE DEC 22 2015
LOW PRESSURE SYSTEM WILL BRING RA TO SITES WITH CEILINGS AND
VISIBILITIES REMAINING MVFR AND LIKELY DROPPING TO IFR OR LIFR
WITH RA...GENERALLY BEYOND 12Z. EXPECT CONDITIONS TO IMPROVE
NEAR/AFTER 00Z AT SITES...THOUGH MVFR CEILINGS MAY LINGER. COULD
SEE SN AT NORTHERN SITES KMCW/KALO NEAR 00Z...BUT HAVE LEFT
MENTION OUT ATTM. WINDS WILL BE STRONG...SHIFTING TO THE NORTHWEST
AND BECOMING STRONG AND GUSTY NEAR/AFTER 00Z.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...SKOW
LONG TERM...SMALL
AVIATION...AWB
AREA FORECAST DISCUSSION...CORRECTED
NWS DES MOINES IA
436 AM CST WED DEC 23 2015
.SHORT TERM /TODAY/...
ISSUED AT 410 AM CST WED DEC 23 2015
MORNING WATER VAPOR IMAGERY DEPICTS A SEASONABLY STRONG NEGATIVELY
TILTED LONGWAVE TROUGH AXIS SITUATED DOWN THE EASTERN FLANK OF THE
ROCKIES WITH A 150 KT JET IMPINGING ALONG ITS SOUTHWEST FLANK. AN
EMBEDDED SHORTWAVE/PV ANOMALY WILL EJECT NORTHEASTWARD FROM THE BASE
OF THE TROUGH TO THE SOUTHERN MISSOURI RIVER VALLEY BY 00Z THIS
EVENING. A DEEPENING 986 MB SURFACE CYCLONE OVER THE OKLAHOMA
PANHANDLE WILL LIKEWISE LIFT NORTHEASTWARD OVER THE COURSE OF THE
DAY AND BE SITUATED NEAR PRAIRIE DU CHIEN BY 00Z TONIGHT USING THE
GFS SOLUTION...WHICH IS HANDLING THE DEEPENING EVOLUTION OF THE LOW
THE BEST THIS MORNING. THIS WILL BRING A WIDE VARIETY OF WEATHER
ACROSS CENTRAL IOWA TODAY.
STARTING OUT THIS MORNING...A BROAD WARM FRONT CURRENTLY STRETCHES
FROM NEAR OMAHA TO DUBUQUE...WITH TEMPERATURES IN THE MID 30S NORTH
OF THE BOUNDARY TO MID 40S SOUTH. THIS BOUNDARY WILL TIGHTEN DURING
THE COURSE OF THE DAY AS THE LOW APPROACHES...WITH HIGHS RANGING
FROM THE MID 30S NORTHWEST TO NEAR 60 IN THE SOUTHEAST. AS THE LOW
BEGINS TO PULL EASTWARD AFTER 18Z...THIS WILL LIKEWISE PULL THE
BOUNDARY EASTWARD AS A COLD FRONT THIS AFTERNOON AND EVENING.
WIDESPREAD RAIN IS EXPANDING ACROSS THE AREA NOW AS STRONG MIDLEVEL
KINEMATIC/290-300 K ISENTROPIC FORCING INTENSIFIES. INITIAL BOUT OF
PRECIP EARLIER IN THE NIGHT TIED IN WITH A REGION OF THETA-E
ADVECTION HAD TO FIGHT A SUB 800 MB DRY LAYER...BUT THE COLUMN IS
RAPIDLY SATURATING AND PRECIP IS BEING REPORTED AT MULTIPLE SITES.
BEST MIDLEVEL FORCING AND DEEPEST MOISTURE WILL BE COINCIDENT IN THE
15-21Z TIMEFRAME AND HAVE KEPT THE MAX QPF AMOUNTS DURING THIS
WINDOW. PWATS OF 0.50 TO 0.75 INCHES ARE 2 TO 3 STANDARD DEVIATIONS
ABOVE NORMAL AND DAILY TOTAL RAINFALL AMOUNTS OF 0.50 TO 0.75 INCHES
ARE POSSIBLE. THIS WIDESPREAD RAIN WILL LEAD TO RISES IN AREA RIVERS
WHICH HAVE STILL NOT FULLY RECOVERED FROM THE RECORD SETTING DELUGE
A WEEK AND A HALF AGO.
AS THE UPPER LEVEL WAVE MATURES A DRY SLOT WILL WRAP NORTHWARD
ACROSS THE SOUTHERN AND EASTERN PORTIONS OF THE STATE BETWEEN 18 AND
00Z. CURRENT POP AND QPF GRIDS MAY BE A LITTLE CONSERVATIVE ON THE
TIMING OF THIS DRY SLOT OVER SOUTHERN IOWA...BUT GIVEN THE SLOWER
TRENDS OF RECENT MODEL RUNS...HAVE KEPT CATEGORICAL POPS OVER THE
SOUTH UNTIL 16-17Z. THIS DRY SLOT WILL ALSO RESULT IN STEEPENING MID
LEVEL LAPSE RATES AND INCREASING INSTABILITY OVER THE SOUTHEASTERN
PORTION OF THE CWA. RAP BUFR SOUNDINGS FROM OTTUMWA SHOW 300-500
J/KG OF MUCAPE DEVELOPING BETWEEN 18-20Z. 0-6 KM SHEAR VALUES OF 40
TO 50 KTS WILL BE MORE THAN CAPABLE OF MAINTAINING ANY THUNDERSTORMS
THAT DO DEVELOP IN THE WARM SECTOR EARLY THIS AFTERNOON. THE THREAT
FOR ORGANIZED AND SEVERE CONVECTION WILL BE CONFINED TO A VERY
NARROW AND CONDITIONAL WINDOW ACROSS THE FAR SOUTHEAST...AND WITH
STORM MOTIONS OF 40 TO 50 KTS TO THE NORTHEAST...THESE STORMS WILL
RAPIDLY EXIT THE CWA. THE MAIN THREAT WOULD BE LARGE HAIL GIVEN THE
LOW FREEZING LEVELS...BUT IF SOMEHOW ANY SOLAR INSOLATION WERE TO
TAKE PLACE AND THE STORMS DID GO SURFACE BASED...THE 35 KTS OF 0-1
KM SHEAR AND PROXIMITY TO THE SURFACE LOW WOULD SUPPORT TORNADOES.
AGAIN...THE THREAT FOR ANY SEVERE WEATHER...LET ALONE TORNADOES...IS
VERY CONDITIONAL AND LIMITED TO A SHORT WINDOW FROM AROUND 19-22Z.
NEXT ON THE DOCKET ARE WINDS ON THE BACKSIDE OF THE LOW. A
TIGHTENING PRESSURE GRADIENT AND STRONG PRESSURE RISE COUPLET
IMMEDIATELY FOLLOWING THE LOW WILL RESULT IN WINDS OF 20 TO 25 KTS
SUSTAINED WITH GUSTS OF 30 TO 35 KTS ACROSS SOUTHERN IOWA THROUGH
THE LATE AFTERNOON AND EVENING HOURS. DEFORMATION ZONE AND ELEVATED
FG ZONE WILL LINGER ACROSS THE WESTERN PORTIONS OF THE CWA AS THE
FRONTAL BOUNDARY SLIDES EASTWARD. PRECIP IN THIS ZONE WILL CHANGE
OVER TO SNOW DURING THE COURSE OF THE AFTERNOON AS COOLER AIR MOVES
IN...BUT KEPT SNOW AMOUNTS AROUND A HALF INCH OR LESS GIVEN THE LACK
OF ANY STRONG CAA AND NEAR SURFACE TEMPS STILL IN THE LOW TO MID
30S. ROADS WILL LIKELY JUST STAY WET WITH ACCUMULATIONS ON GRASSY
AREAS.
.LONG TERM /TONIGHT THROUGH TUESDAY/...
ISSUED AT 410 AM CST WED DEC 23 2015
THE PATTERN WILL BE QUITE ACTIVE THROUGH THE ENTIRE PERIOD...WITH
SOME TRAVEL IMPACTS EXPECTED DURING THE EXTENDED...BUT CONFIDENCE
IN DETAILS REMAINS LOW FOR A MULTITUDE OF REASONS. AT ONSET EXPECT
A FRONTOGENETICALLY FORCED DEFORMATION ZONE WITH DEEP VERTICAL
MOTION TO BE QUICKLY RETREATING TO THE NORTH AND EAST EARLY IN THE
EVENING. CONFIDENCE IN SNOW ACCUMS HAS INCREASED...AND DENDRITIC
GROWTH ZONE LIFT WILL BE QUITE STRONG FOR A PERIOD...BUT IT WILL
BE VERY BRIEF AND TRANSIENT. TOTAL ACCUMS WILL GENERALLY BE AN
INCH OR LESS NORTH AND WEST...BUT TOTALS MAY VARY A BIT IN EITHER
DIRECTION DUE TO MELTING ON PAVEMENT VS VEGETATION AND LOCALIZED
HIGHER RATES. ANYTHING TOWARD THE INCH RANGE WOULD BE FAR NORTH.
STRONG SUBSIDENCE WILL THEN SET IN BY NIGHT. MIXING WILL BE FAIRLY
SHALLOW BUT MSLP GRADIENT MAY STILL ALLOW FOR GUSTS TO REACH 35
MPH OR SO THROUGH AT LEAST MIDNIGHT NE.
SHORT WAVE RIDING STRONG NRN CA/OR JET WILL THEN REACH THE MO VALLEY
THU. FORCING AND MOISTURE EXTENT WILL BE QUITE VARIABLE...NEVER
REALLY APPROACHING SATURATION. THIS WILL RESULT IN ANY AMOUNTS
BEING QUITE LIGHT...AND PTYPE IN QUESTION DUE TO ONLY A SMALL
WINDOW OF ICE INTRODUCTION. THUS HAVE LOW CHANCES WITH BOTH LIGHT
SNOW OR FLURRIES...AND LIGHT FREEZING RAIN/SPRINKLES POSSIBLE.
SHOULD SEE A BRIEF BREAK IN PRECIP THU NIGHT BEFORE SHORT WAVES
REACH CA AND CONTINUE TO CARVE OUT WRN CONUS LONG WAVE TROUGH...AND
EVENTUAL CUTOFF. THIS SETS UP A PROLONGED PERIOD OF SWLY FLOW
ALOFT...AND INVERTED TROUGHINESS INTO THE MID MS VALLEY. AS THE
CLOSED LOW FORMS IN THE SW...A SHORT WAVE WILL SPLIT AND RIDE THE SW
FLOW INTO THE MO VALLEY EARLY IN THE WEEKEND. PRECIP CHANCES WILL
INCREASE SHARPLY FRI INTO FRI NIGHT. ALTHOUGH THE DEEPEST QG FORCING
WILL REMAIN JUST TO OUR NORTH AND WEST...THE H85/H7 FORCING IS
EXTREME WITH HIGH CONTRIBUTIONS FROM THETA-E ADVECTION AND
FRONTOGENESIS. SNOWFALL RATES OVER NRN IA MAY BRIEFLY BE QUITE HIGH
WITH LOW STABILITY. GFS TICKS OFF SOME MUCAPES AND...ALTHOUGH
FAIRLY ELEVATED...ALSO SHOWS NEGATIVE SAT EPV WHICH WOULD BE
EXPECTED WITH THE LOW STATIC STABILITY AND MUCAPE REFLECTION. THUS
HAVE AN INCH OR TWO OF SNOW ACCUMS POSSIBLE NORTH THROUGH 12Z SAT
WITH ADDITIONAL AMOUNTS POSSIBLE AFTER THAT TIME. THE WAVE THEN
MOVES AWAY LATER SAT WITH THE ATTENTION TURNING TOWARD THE
APPROACHING CUTOFF LOW. SOME POPS LINGER THROUGH THE
WEEKEND...ESPECIALLY SOUTH...BUT NEITHER THE FIC/290-300 K
ISENTROPIC FORCING OR MOISTURE IS TOO IMPRESSIVE.
THE PROGRESSION OF THE CUTOFF LOW WILL LIKELY RESULT IN THE BIGGEST
TRAVEL IMPACT OF THE HOLIDAY TRAVEL SEASON...BUT DETAILS ARE FAR
FROM CLEAR CUT. THE ECMWF HAS BEEN FAIRLY CONSISTENT WITH ITS
FARTHER WEST AND LESS SNOWY TRACK...BUT VARIABLE IN TIME OVER
RECENT RUNS. THE GFS TRACK AND TIMING HAVE BEEN MORE
CONSISTENT...AND POINT TOWARD A WIND BLOW HEAVY SNOW EVENT...BUT
IS A FASTER OUTLIER VS THE SLOWER CANADIAN AND ECMWF. RATHER THAN
FOCUSING ON THE DETAILS THE MAIN TAKE HOME POINT FOR NOW WOULD
APPEAR TO BE A SIGNIFICANT SYSTEM WILL AFFECT HOLIDAY TRAVEL IN OR
NEAR IA SOMETIME AROUND MON OR MON NIGHT. FOR THE TIME BEING HAVE
EITHER RAIN OR SNOW IN THE FORECAST WITH LOW CONFIDENCE...BUT THE
ECMWF ALSO HINTS AT THE POSSIBILITY OF A FREEZING RAIN/ICING EVENT
NRN HALF WITH A NICE ELEVATED WARM LAYER ABOVE SUB FREEZING
SURFACE TEMPS AND A BRISK ELY WIND. WILL NEED TO CONTINUE TO
MONITOR FOR THE POTENTIAL FOR EITHER ICING OR SNOW. WHATEVER
OCCURS LOOKS TO BE GONE BY TUE NIGHT EVEN WITH THE SLOWER ECMWF
SOLUTION.
&&
.AVIATION...23/06Z
ISSUED AT 1126 PM CST TUE DEC 22 2015
LOW PRESSURE SYSTEM WILL BRING RA TO SITES WITH CEILINGS AND
VISIBILITIES REMAINING MVFR AND LIKELY DROPPING TO IFR OR LIFR
WITH RA...GENERALLY BEYOND 12Z. EXPECT CONDITIONS TO IMPROVE
NEAR/AFTER 00Z AT SITES...THOUGH MVFR CEILINGS MAY LINGER. COULD
SEE SN AT NORTHERN SITES KMCW/KALO NEAR 00Z...BUT HAVE LEFT
MENTION OUT ATTM. WINDS WILL BE STRONG...SHIFTING TO THE NORTHWEST
AND BECOMING STRONG AND GUSTY NEAR/AFTER 00Z.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...SKOW
LONG TERM...SMALL
AVIATION...AWB
AREA FORECAST DISCUSSION
NWS DES MOINES IA
416 AM CST WED DEC 23 2015
.SHORT TERM /TODAY/...
ISSUED AT 410 AM CST WED DEC 23 2015
MORNING WATER VAPOR IMAGERY DEPICTS A SEASONABLY STRONG NEGATIVELY
TILTED LONGWAVE TROUGH AXIS SITUATED DOWN THE EASTERN FLANK OF THE
ROCKIES WITH A 150 KT JET IMPINGING ALONG ITS SOUTHWEST FLANK. AN
EMBEDDED SHORTWAVE/PV ANOMALY WILL EJECT NORTHEASTWARD FROM THE BASE
OF THE TROUGH TO THE SOUTHERN MISSOURI RIVER VALLEY BY 00Z THIS
EVENING. A DEEPENING 986 MB SURFACE CYCLONE OVER THE OKLAHOMA
PANHANDLE WILL LIKEWISE LIFT NORTHEASTWARD OVER THE COURSE OF THE
DAY AND BE SITUATED NEAR PRAIRIE DU CHIEN BY 00Z TONIGHT USING THE
GFS SOLUTION...WHICH IS HANDLING THE DEEPENING EVOLUTION OF THE LOW
THE BEST THIS MORNING. THIS WILL BRING A WIDE VARIETY OF WEATHER
ACROSS CENTRAL IOWA TODAY.
STARTING OUT THIS MORNING...A BROAD WARM FRONT CURRENTLY STRETCHES
FROM NEAR OMAHA TO DUBUQUE...WITH TEMPERATURES IN THE MID 30S NORTH
OF THE BOUNDARY TO MID 40S SOUTH. THIS BOUNDARY WILL TIGHTEN DURING
THE COURSE OF THE DAY AS THE LOW APPROACHES...WITH HIGHS RANGING
FROM THE MID 30S NORTHWEST TO NEAR 60 IN THE SOUTHEAST. AS THE LOW
BEGINS TO PULL EASTWARD AFTER 18Z...THIS WILL LIKEWISE PULL THE
BOUNDARY EASTWARD AS A COLD FRONT THIS AFTERNOON AND EVENING.
WIDESPREAD RAIN IS EXPANDING ACROSS THE AREA NOW AS STRONG MIDLEVEL
KINEMATIC/290-300 K ISENTROPIC FORCING INTENSIFIES. INITIAL BOUT OF
PRECIP EARLIER IN THE NIGHT TIED IN WITH A REGION OF THETA-E
ADVECTION HAD TO FIGHT A SUB 800 MB DRY LAYER...BUT THE COLUMN IS
RAPIDLY SATURATING AND PREMORNING WATER VAPOR IMAGERY DEPICTS A
SEASONABLY STRONG NEGATIVELY TILTED LONGWAVE TROUGH AXIS SITUATED
DOWN THE EASTERN FLANK OF THE ROCKIES WITH A 150 KT JET IMPINGING
ALONG ITS SOUTHWEST FLANK. AN EMBEDDED SHORTWAVE/PV ANOMALY WILL
EJECT NORTHEASTWARD FROM THE BASE OF THE TROUGH TO THE SOUTHERN
MISSOURI RIVER VALLEY BY 00Z THIS EVENING. A DEEPENING 986 MB
SURFACE CYCLONE OVER THE OKLAHOMA PANHANDLE WILL LIKEWISE LIFT
NORTHEASTWARD OVER THE COURSE OF THE DAY AND BE SITUATED NEAR
PRAIRIE DU CHIEN BY 00Z TONIGHT USING THE GFS SOLUTION...WHICH IS
HANDLING THE DEEPENING EVOLUTION OF THE LOW THE BEST THIS MORNING.
THIS WILL BRING A WIDE VARIETY OF WEATHER ACROSS CENTRAL IOWA
TODAY.
STARTING OUT THIS MORNING...A BROAD WARM FRONT CURRENTLY STRETCHES
FROM NEAR OMAHA TO DUBUQUE...WITH TEMPERATURES IN THE MID 30S NORTH
OF THE BOUNDARY TO MID 40S SOUTH. THIS BOUNDARY WILL TIGHTEN DURING
THE COURSE OF THE DAY AS THE LOW APPROACHES...WITH HIGHS RANGING
FROM THE MID 30S NORTHWEST TO NEAR 60 IN THE SOUTHEAST. AS THE LOW
BEGINS TO PULL EASTWARD AFTER 18Z...THIS WILL LIKEWISE PULL THE
BOUNDARY EASTWARD AS A COLD FRONT THIS AFTERNOON AND EVENING.
WIDESPREAD RAIN IS EXPANDING ACROSS THE AREA NOW AS STRONG MIDLEVEL
KINEMATIC/290-300 K ISENTROPIC FORCING INTENSIFIES. INITIAL BOUT OF
PRECIP EARLIER IN THE NIGHT TIED IN WITH A REGION OF THETA-E
ADVECTION HAD TO FIGHT A SUB 800 MB DRY LAYER...BUT THE COLUMN IS
RAPIDLY SATURATING AND PRECIP IS BEING REPORTED AT MULTIPLE SITES.
BEST MIDLEVEL FORCING AND DEEPEST MOISTURE WILL BE COINCIDENT IN THE
15-21Z TIMEFRAME AND HAVE KEPT THE MAX QPF AMOUNTS DURING THIS
WINDOW. PWATS OF 0.50 TO 0.75 INCHES ARE 2 TO 3 STANDARD DEVIATIONS
ABOVE NORMAL AND DAILY TOTAL RAINFALL AMOUNTS OF 0.50 TO 0.75 INCHES
ARE POSSIBLE. THIS WIDESPREAD RAIN WILL LEAD TO RISES IN AREA RIVERS
WHICH HAVE STILL NOT FULLY RECOVERED FROM THE RECORD SETTING DELUGE
A WEEK AND A HALF AGO.
AS THE UPPER LEVEL WAVE MATURES A DRY SLOT WILL WRAP NORTHWARD
ACROSS THE SOUTHERN AND EASTERN PORTIONS OF THE STATE BETWEEN 18 AND
00Z. CURRENT POP AND QPF GRIDS MAY BE A LITTLE CONSERVATIVE ON THE
TIMING OF THIS DRY SLOT OVER SOUTHERN IOWA...BUT GIVEN THE SLOWER
TRENDS OF RECENT MODEL RUNS...HAVE KEPT CATEGORICAL POPS OVER THE
SOUTH UNTIL 16-17Z. THIS DRY SLOT WILL ALSO RESULT IN STEEPENING MID
LEVEL LAPSE RATES AND INCREASING INSTABILITY OVER THE SOUTHEASTERN
PORTION OF THE CWA. RAP BUFR SOUNDINGS FROM OTTUMWA SHOW 300-500
J/KG OF MUCAPE DEVELOPING BETWEEN 18-20Z. 0-6 KM SHEAR VALUES OF 40
TO 50 KTS WILL BE MORE THAN CAPABLE OF MAINTAINING ANY THUNDERSTORMS
THAT DO DEVELOP IN THE WARM SECTOR EARLY THIS AFTERNOON. THE THREAT
FOR ORGANIZED AND SEVERE CONVECTION WILL BE CONFINED TO A VERY
NARROW AND CONDITIONAL WINDOW ACROSS THE FAR SOUTHEAST...AND WITH
STORM MOTIONS OF 40 TO 50 KTS TO THE NORTHEAST...THESE STORMS WILL
RAPIDLY EXIT THE CWA. THE MAIN THREAT WOULD BE LARGE HAIL GIVEN THE
LOW FREEZING LEVELS...BUT IF SOMEHOW ANY SOLAR INSOLATION WERE TO
TAKE PLACE AND THE STORMS DID GO SURFACE BASED...THE 35 KTS OF 0-1
KM SHEAR AND PROXIMITY TO THE SURFACE LOW WOULD SUPPORT TORNADOES.
AGAIN...THE THREAT FOR ANY SEVERE WEATHER...LET ALONE TORNADOES...IS
VERY CONDITIONAL AND LIMITED TO A SHORT WINDOW FROM AROUND 19-22Z.
NEXT ON THE DOCKET ARE WINDS ON THE BACKSIDE OF THE LOW. A
TIGHTENING PRESSURE GRADIENT AND STRONG PRESSURE RISE COUPLET
IMMEDIATELY FOLLOWING THE LOW WILL RESULT IN WINDS OF 20 TO 25 KTS
SUSTAINED WITH GUSTS OF 30 TO 35 KTS ACROSS SOUTHERN IOWA THROUGH
THE LATE AFTERNOON AND EVENING HOURS. DEFORMATION ZONE AND ELEVATED
FG ZONE WILL LINGER ACROSS THE WESTERN PORTIONS OF THE CWA AS THE
FRONTAL BOUNDARY SLIDES EASTWARD. PRECIP IN THIS ZONE WILL CHANGE
OVER TO SNOW DURING THE COURSE OF THE AFTERNOON AS COOLER AIR MOVES
IN...BUT KEPT SNOW AMOUNTS AROUND A HALF INCH OR LESS GIVEN THE LACK
OF ANY STRONG CAA AND NEAR SURFACE TEMPS STILL IN THE LOW TO MID
30S. ROADS WILL LIKELY JUST STAY WET WITH ACCUMULATIONS ON GRASSY
AREAS.CIP IS BEING REPORTED AT MULTIPLE SITES. BEST MIDLEVEL
FORCING AND DEEPEST MOISTURE WILL BE COINCIDENT IN THE 15-21Z
TIMEFRAME AND HAVE KEPT THE MAX QPF AMOUNTS DURING THIS WINDOW.
PWATS OF 0.50 TO 0.75 INCHES ARE 2 TO 3 STANDARD DEVIATIONS ABOVE
NORMAL AND DAILY TOTAL RAINFALL AMOUNTS OF 0.50 TO 0.75 INCHES ARE
POSSIBLE. THIS WIDESPREAD RAIN WILL LEAD TO RISES IN AREA RIVERS
WHICH HAVE STILL NOT FULLY RECOVERED FROM THE RECORD SETTING
DELUGE A WEEK AND A HALF AGO.
AS THE UPPER LEVEL WAVE MATURES A DRY SLOT WILL WRAP NORTHWARD
ACROSS THE SOUTHERN AND EASTERN PORTIONS OF THE STATE BETWEEN 18 AND
00Z. CURRENT POP AND QPF GRIDS MAY BE A LITTLE CONSERVATIVE ON THE
TIMING OF THIS DRY SLOT OVER SOUTHERN IOWA...BUT GIVEN THE SLOWER
TRENDS OF RECENT MODEL RUNS...HAVE KEPT CATEGORICAL POPS OVER THE
SOUTH UNTIL 16-17Z. THIS DRY SLOT WILL ALSO RESULT IN STEEPENING MID
LEVEL LAPSE RATES AND INCREASING INSTABILITY OVER THE SOUTHEASTERN
PORTION OF THE CWA. RAP BUFR SOUNDINGS FROM OTTUMWA SHOW 300-500
J/KG OF MUCAPE DEVELOPING BETWEEN 18-20Z. 0-6 KM SHEAR VALUES OF 40
TO 50 KTS WILL BE MORE THAN CAPABLE OF MAINTAINING ANY THUNDERSTORMS
THAT DO DEVELOP IN THE WARM SECTOR EARLY THIS AFTERNOON. THE THREAT
FOR ORGANIZED AND SEVERE CONVECTION WILL BE CONFINED TO A VERY
NARROW AND CONDITIONAL WINDOW ACROSS THE FAR SOUTHEAST...AND WITH
STORM MOTIONS OF 40 TO 50 KTS TO THE NORTHEAST...THESE STORMS WILL
RAPIDLY EXIT THE CWA. THE MAIN THREAT WOULD BE LARGE HAIL GIVEN THE
LOW FREEZING LEVELS...BUT IF SOMEHOW ANY SOLAR INSOLATION WERE TO
TAKE PLACE AND THE STORMS DID GO SURFACE BASED...THE 35 KTS OF 0-1
KM SHEAR AND PROXIMITY TO THE SURFACE LOW WOULD SUPPORT TORNADOES.
AGAIN...THE THREAT FOR ANY SEVERE WEATHER...LET ALONE TORNADOES...IS
VERY CONDITIONAL AND LIMITED TO A SHORT WINDOW FROM AROUND 19-22Z.
NEXT ON THE DOCKET ARE WINDS ON THE BACKSIDE OF THE LOW. A
TIGHTENING PRESSURE GRADIENT AND STRONG PRESSURE RISE COUPLET
IMMEDIATELY FOLLOWING THE LOW WILL RESULT IN WINDS OF 20 TO 25 KTS
SUSTAINED WITH GUSTS OF 30 TO 35 KTS ACROSS SOUTHERN IOWA THROUGH
THE LATE AFTERNOON AND EVENING HOURS. DEFORMATION ZONE AND ELEVATED
FG ZONE WILL LINGER ACROSS THE WESTERN PORTIONS OF THE CWA AS THE
FRONTAL BOUNDARY SLIDES EASTWARD. PRECIP IN THIS ZONE WILL CHANGE
OVER TO SNOW DURING THE COURSE OF THE AFTERNOON AS COOLER AIR MOVES
IN...BUT KEPT SNOW AMOUNTS AROUND A HALF INCH OR LESS GIVEN THE LACK
OF ANY STRONG CAA AND NEAR SURFACE TEMPS STILL IN THE LOW TO MID
30S. ROADS WILL LIKELY JUST STAY WET WITH ACCUMULATIONS ON GRASSY
AREAS.
.LONG TERM /TONIGHT THROUGH TUESDAY/...
ISSUED AT 410 AM CST WED DEC 23 2015
THE PATTERN WILL BE QUITE ACTIVE THROUGH THE ENTIRE PERIOD...WITH
SOME TRAVEL IMPACTS EXPECTED DURING THE EXTENDED...BUT CONFIDENCE
IN DETAILS REMAINS LOW FOR A MULTITUDE OF REASONS. AT ONSET EXPECT
A FRONTOGENETICALLY FORCED DEFORMATION ZONE WITH DEEP VERTICAL
MOTION TO BE QUICKLY RETREATING TO THE NORTH AND EAST EARLY IN THE
EVENING. CONFIDENCE IN SNOW ACCUMS HAS INCREASED...AND DENDRITIC
GROWTH ZONE LIFT WILL BE QUITE STRONG FOR A PERIOD...BUT IT WILL
BE VERY BRIEF AND TRANSIENT. TOTAL ACCUMS WILL GENERALLY BE AN
INCH OR LESS NORTH AND WEST...BUT TOTALS MAY VARY A BIT IN EITHER
DIRECTION DUE TO MELTING ON PAVEMENT VS VEGETATION AND LOCALIZED
HIGHER RATES. ANYTHING TOWARD THE INCH RANGE WOULD BE FAR NORTH.
STRONG SUBSIDENCE WILL THEN SET IN BY NIGHT. MIXING WILL BE FAIRLY
SHALLOW BUT MSLP GRADIENT MAY STILL ALLOW FOR GUSTS TO REACH 35
MPH OR SO THROUGH AT LEAST MIDNIGHT NE.
SHORT WAVE RIDING STRONG NRN CA/OR JET WILL THEN REACH THE MO VALLEY
THU. FORCING AND MOISTURE EXTENT WILL BE QUITE VARIABLE...NEVER
REALLY APPROACHING SATURATION. THIS WILL RESULT IN ANY AMOUNTS
BEING QUITE LIGHT...AND PTYPE IN QUESTION DUE TO ONLY A SMALL
WINDOW OF ICE INTRODUCTION. THUS HAVE LOW CHANCES WITH BOTH LIGHT
SNOW OR FLURRIES...AND LIGHT FREEZING RAIN/SPRINKLES POSSIBLE.
SHOULD SEE A BRIEF BREAK IN PRECIP THU NIGHT BEFORE SHORT WAVES
REACH CA AND CONTINUE TO CARVE OUT WRN CONUS LONG WAVE TROUGH...AND
EVENTUAL CUTOFF. THIS SETS UP A PROLONGED PERIOD OF SWLY FLOW
ALOFT...AND INVERTED TROUGHINESS INTO THE MID MS VALLEY. AS THE
CLOSED LOW FORMS IN THE SW...A SHORT WAVE WILL SPLIT AND RIDE THE SW
FLOW INTO THE MO VALLEY EARLY IN THE WEEKEND. PRECIP CHANCES WILL
INCREASE SHARPLY FRI INTO FRI NIGHT. ALTHOUGH THE DEEPEST QG FORCING
WILL REMAIN JUST TO OUR NORTH AND WEST...THE H85/H7 FORCING IS
EXTREME WITH HIGH CONTRIBUTIONS FROM THETA-E ADVECTION AND
FRONTOGENESIS. SNOWFALL RATES OVER NRN IA MAY BRIEFLY BE QUITE HIGH
WITH LOW STABILITY. GFS TICKS OFF SOME MUCAPES AND...ALTHOUGH
FAIRLY ELEVATED...ALSO SHOWS NEGATIVE SAT EPV WHICH WOULD BE
EXPECTED WITH THE LOW STATIC STABILITY AND MUCAPE REFLECTION. THUS
HAVE AN INCH OR TWO OF SNOW ACCUMS POSSIBLE NORTH THROUGH 12Z SAT
WITH ADDITIONAL AMOUNTS POSSIBLE AFTER THAT TIME. THE WAVE THEN
MOVES AWAY LATER SAT WITH THE ATTENTION TURNING TOWARD THE
APPROACHING CUTOFF LOW. SOME POPS LINGER THROUGH THE
WEEKEND...ESPECIALLY SOUTH...BUT NEITHER THE FORCING OR MOISTURE
IS TOO IMPRESSIVE.
THE PROGRESSION OF THE CUTOFF LOW WILL LIKELY RESULT IN THE BIGGEST
TRAVEL IMPACT OF THE HOLIDAY TRAVEL SEASON...BUT DETAILS ARE FAR
FROM CLEAR CUT. THE ECMWF HAS BEEN FAIRLY CONSISTENT WITH ITS
FARTHER WEST AND LESS SNOWY TRACK...BUT VARIABLE IN TIME OVER
RECENT RUNS. THE GFS TRACK AND TIMING HAVE BEEN MORE
CONSISTENT...AND POINT TOWARD A WIND BLOW HEAVY SNOW EVENT...BUT
IS A FASTER OUTLIER VS THE SLOWER CANADIAN AND ECMWF. RATHER THAN
FOCUSING ON THE DETAILS THE MAIN TAKE HOME POINT FOR NOW WOULD
APPEAR TO BE A SIGNIFICANT SYSTEM WILL AFFECT HOLIDAY TRAVEL IN OR
NEAR IA SOMETIME AROUND MON OR MON NIGHT. FOR THE TIME BEING HAVE
EITHER RAIN OR SNOW IN THE FORECAST WITH LOW CONFIDENCE...BUT THE
ECMWF ALSO HINTS AT THE POSSIBILITY OF A FREEZING RAIN/ICING EVENT
NRN HALF WITH A NICE ELEVATED WARM LAYER ABOVE SUB FREEZING
SURFACE TEMPS AND A BRISK ELY WIND. WILL NEED TO CONTINUE TO
MONITOR FOR THE POTENTIAL FOR EITHER ICING OR SNOW. WHATEVER
OCCURS LOOKS TO BE GONE BY TUE NIGHT EVEN WITH THE SLOWER ECMWF
SOLUTION.
&&
.AVIATION...23/06Z
ISSUED AT 1126 PM CST TUE DEC 22 2015
LOW PRESSURE SYSTEM WILL BRING RA TO SITES WITH CEILINGS AND
VISIBILITIES REMAINING MVFR AND LIKELY DROPPING TO IFR OR LIFR
WITH RA...GENERALLY BEYOND 12Z. EXPECT CONDITIONS TO IMPROVE
NEAR/AFTER 00Z AT SITES...THOUGH MVFR CEILINGS MAY LINGER. COULD
SEE SN AT NORTHERN SITES KMCW/KALO NEAR 00Z...BUT HAVE LEFT
MENTION OUT ATTM. WINDS WILL BE STRONG...SHIFTING TO THE NORTHWEST
AND BECOMING STRONG AND GUSTY NEAR/AFTER 00Z.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...SKOW
LONG TERM...SMALL
AVIATION...AWB
AREA FORECAST DISCUSSION
NWS JACKSON KY
1019 AM EST WED DEC 23 2015
.UPDATE...
ISSUED AT 1019 AM EST WED DEC 23 2015
SHOWERS ARE DIMINISHING LATE THIS MORNING AS THE AREA OF PRECIP
EXITS TO THE EAST. THERE IS A SIZABLE HOLE IN THE ACTIVITY
UPSTREAM TO OUR WEST AND SOUTHWEST. MODEL FORECAST SOUNDINGS
SUGGEST THIS WILL PERSIST OVER THE JKL FORECAST AREA AS IT
PROPAGATES THROUGH...WITH MID/UPPER LEVEL DRYING TAKING PLACE AS A
LOW LEVEL CAP PERSISTS. DEEP CONVECTION COULD BEGIN TO SHOW UP
FROM THE WEST BY THE END OF THE DAY.
UPDATE ISSUED AT 654 AM EST WED DEC 23 2015
SHOWERS NOW EXPANDING ACROSS THE AREA AS THE WARM FRONT LIFTS
NORTH. LOOKS LIKE MOST OF THE RAIN WILL OCCUR IN THE NEXT FEW
HOURS...BUT A FEW SHOWERS WILL REMAIN POSSIBLE INTO THE EARLY
AFTERNOON HOURS AS A MOIST ENVIRONMENT REMAINS OVER THE AREA.
LOOKS LIKE THE SEVERE STORMS SHOULD BE KNOCKING ON OUR DOOR
SHORTLY AFTER 9 PM THIS EVENING. OUR FORECAST GRAPHICAL TIMING
LOOKS EXCELLENT RIGHT NOW.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 343 AM EST WED DEC 23 2015
...SEVERE STORMS WITH DAMAGING WINDS POSSIBLE TONIGHT...
A RATHER ACTIVE...SPRING-LIKE PATTERN EXPECTED OVER THE NEXT 36
HOURS. PRESENTLY...A WARM FRONT IS LIFTING NORTH ACROSS TENNESSEE.
SOUTHEAST WINDS TO THE NORTH OF THE FRONT HAS KEPT MUCH OF EASTERN
KENTUCKY DRY OVERNIGHT. HOWEVER...THIS IS ABOUT TO CHANGE AS THE
FRONT CONTINUES TO PUSH NORTH THIS MORNING AND WINDS TURN MORE
SOUTHERLY. THE INITIAL SURGE OF MID LEVEL ISENTROPIC ASCENT HAS
GENERATED A LARGER POCKET OF RAINFALL OVER THE CUMBERLAND
PLATEAU...AND THIS RAIN WILL MOVE NORTH ACROSS OUR WESTERN
COUNTIES THROUGH 7 AM. INCREASED POPS TO CATEGORICAL WITH THIS
RAIN SPREADING NORTH. TO THE EAST...WE SHOULD REMAIN WITH VERY
LITTLE AS THE DOWNSLOPING CONTINUES TO EAT AWAY AT SHOWERS TRYING
TO PUSH NORTH. EVENTUALLY THE DRY AIR WILL BE OVERCOME...LIKELY
AROUND OR SHORTLY AFTER 7 AM...WITH SCATTERED SHOWERS PUSHING
NORTH ACROSS THE REGION THROUGH THE MORNING. HRRR HAS BEEN
CONSISTENT ON LINGERING SHOWERS INTO THE AFTERNOON...SO HAVE
KEPT POPS IN THE FORECAST THROUGH EARLY AFTERNOON. IT DOES APPEAR
WE SHOULD SEE A BETTER BREAK IN PRECIPITATION BY LATE AFTERNOON
THROUGH THE EARLY EVENING HOURS..AS SUBSIDENCE SPREADS IN AHEAD OF
THE APPROACHING COLD FRONT.
WITH THE FRONT APPROACHING THIS AFTERNOON...THE GRADIENT SHOULD
INCREASE AND WE WILL SEE GUSTY WINDS DEVELOP AREA WIDE. THE NAM
BUFKIT MOMENTUM TRANSFER EQUATION SUPPORTS 3O TO 35 MPH WIND
GUSTS...ESPECIALLY OUT ACROSS CENTRAL KENTUCKY...EXTENDING ACROSS
THE BLUEGRASS. WIND GUSTS UP TO 25 WILL REMAIN POSSIBLE TO THE
EAST. PUT IN A MENTION IN THE HWO OF THE GUSTY WINDS THIS
AFTERNOON.
FINALLY...MOVING ONTO THE SEVERE POTENTIAL TONIGHT. MODELS ARE
STILL NOT IN GREAT AGREEMENT ON OVERALL TIMING...AS A FEW OF THE
HI-RES MODELS SUPPORT AN EARLIER ROUND OF CONVECTION IN THE
EVENING...WHILE OTHERS HOLD OFF UNTIL OVERNIGHT. THUS...CONFIDENCE
IS HIGH ON THE THREAT FOR SEVERE STORMS OCCURRING TONIGHT...THERE
REMAINS CONSIDERABLE SPREAD ON WHETHER IT OCCURS MID TO LATE
EVENING OR AFTER MIDNIGHT. REGARDLESS OF TIMING...SHEAR GENERATED
WITH THE STRENGTH OF THE LOW LEVEL JET IS TREMENDOUS AND WILL
SUPPORT THE SEVERE STORM POTENTIAL. THE EXACT QUESTION IS HOW MUCH
INSTABILITY WILL BE PRESENT AS THE STORMS CROSS INTO EASTERN
KENTUCKY TONIGHT. NAM BUFKIT SOUNDINGS SHOW SOME POTENTIAL FOR
600-1000J/KG OF SBCAPE...WHICH IS MARGINAL...BUT COULD BE ENOUGH
TO ALLOW WINDS TO REACH THE SURFACE...ESPECIALLY IF WE END UP
DEALING WITH MORE LINE SEGMENTS. THUS...THE STORM PREDICTION
CENTER HAS EXPANDED THE ENHANCED RISK OF SEVERE STORMS INTO
CENTRAL KENTUCKY. IF WE DO END UP WITH A QLCS/LINE OF STORMS...
A SPIN UP TORNADO WOULD ALSO BE POSSIBLE ALONG THE LINE WITH SUCH
STRONG SHEAR NEARLY NORMAL TO THE ADVANCING STORMS. WILL CONTINUE
TO HIGHLIGHT DAMAGING WINDS/TORNADO THREAT IN THE HWO AND PLAN TO
DO A MORNING WEB BRIEFING TO HIGHLIGHT THE THREAT.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 359 AM EST WED DEC 23 2015
THE MODELS REMAIN IN GOOD GENERAL AGREEMENT WITH THE AMPLIFIED AND
ACTIVE LONG WAVE PATTERN THROUGH EARLY NEXT WEEK...AS THE SUMMER-
LIKE BERMUDA HIGH VERY GRADUALLY SHIFTS TOWARDS THE BAHAMAS BY
EARLY NEXT WEEK. MEANWHILE...DEEP AND BROAD TROUGHING IN THE
WESTERN HALF OF THE NATION TRANSITIONS TO SPLIT FLOW BY THE
HOLIDAY WEEKEND. A CUTOFF LOW WILL DROP SOUTHEAST INTO
TEXAS/MEXICO...AND THEN SWING NORTHEAST INTO THE PLAINS AND
EVENTUALLY GREAT LAKES/OHIO VALLEY REGIONS BY EARLY NEXT WEEK.
NEAR RECORD TO RECORD TEMPERATURES AT TIMES...ALONG WITH SEVERAL
ROUNDS OF WET WEATHER STILL LOOK IN THE OFFING FOR THE OHIO AND
TENNESSEE VALLEYS THROUGH THE PERIOD.
A FRONTAL BOUNDARY WILL BE STALLING ACROSS OUR AREA THURSDAY
NIGHT...WITH A SURGE OF LOW LEVEL MOISTURE COMING IN BY FRIDAY
MORNING. CONFIDENCE REGARDING HOW MUCH RAINFALL WE WILL SEE
FRIDAY INTO FRIDAY NIGHT AS THE FRONTAL BOUNDARY GRADUALLY LIFTS
NORTH AS A WARM FRONT CONTINUES TO BE ON THE LOW SIDE. PWATS ARE
VERY HIGH...HOWEVER MID AND UPPER LEVEL SUPPORT IS NOT THAT
IMPRESSIVE...SO AM NOT CONVINCED THAT THE MAJORITY OF THE MOISTURE
WILL BE TAPPED DESPITE THE AMPLE LOW LEVEL JET IN PLACE. AS
SUCH...HAVE CONTINUED TO KEEP THINGS GENERALIZED CONCERNING THE
FLOOD POTENTIAL UNTIL THERE IS BETTER MODEL AGREEMENT.
THE BAROCLINIC ZONE WILL SHIFT NORTH OF OUR AREA BY LATE SATURDAY
INTO SATURDAY NIGHT...LEADING TO LESSER CHANCES OF POPS ACROSS OUR
AREA. THE MODELS HAVE BEEN WAFFLING SUNDAY INTO MONDAY...WITH THE
ECMWF SUGGESTING A NORTHERN STREAM TROUGH HAVING ENOUGH PUSH TO
SEND THE BOUNDARY BACK ACROSS OUR AREA ON SUNDAY...AND THEN
HOLDING BACK THE NEXT FRONT UNTIL MAINLY TUESDAY. THE GFS HAS A
LITTLE BETTER CONTINUITY...KEEPING THE BOUNDARY JUST TO OUR
NORTH...UNTIL THE NEXT SURGE OF MOISTURE ARRIVES MONDAY NIGHT.
GIVEN THE UNCERTAINTY...STUCK FAIRLY CLOSE TO THE BLENDED
GUIDANCE...ALTHOUGH DID LINGER POPS A BIT LONGER INTO TUESDAY TO
ALLOW FOR A POTENTIAL SLOWER EXIT.
THE BEST CHANCE TO TEST RECORD HIGHS STILL LOOK TO BE SATURDAY AND
SUNDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 654 AM EST WED DEC 23 2015
WHILE A FEW PERIODS OF MVFR CIGS WILL BE POSSIBLE THIS
MORNING...MAINLY VFR CONDITIONS SHOULD DOMINATE THE WEATHER ACROSS
EASTERN KENTUCKY TODAY. A FEW ISOLATED/SCATTERED SHOWERS WILL
REMAIN POSSIBLE THROUGH AT LEAST EARLY AFTERNOON. A LINE OF
SHOWERS AND STORMS WILL MOVE THROUGH TONIGHT...MAINLY AFTER 9
PM...PRODUCING A PERIOD OF THUNDERSTORMS AT THE TAF SITES. IN
ADDITION SOME GUSTY WINDS ARE EXPECTED THIS AFTERNOON AND EVENING
HEAD OF THIS LINE.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HAL/KAS
SHORT TERM...KAS
LONG TERM...GEOGERIAN
AVIATION...KAS
AREA FORECAST DISCUSSION
NWS JACKSON KY
654 AM EST WED DEC 23 2015
.UPDATE...
ISSUED AT 654 AM EST WED DEC 23 2015
SHOWERS NOW EXPANDING ACROSS THE AREA AS THE WARM FRONT LIFTS
NORTH. LOOKS LIKE MOST OF THE RAIN WILL OCCUR IN THE NEXT FEW
HOURS...BUT A FEW SHOWERS WILL REMAIN POSSIBLE INTO THE EARLY
AFTERNOON HOURS AS A MOIST ENVIRONMENT REMAINS OVER THE AREA.
LOOKS LIKE THE SEVERE STORMS SHOULD BE KNOCKING ON OUR DOOR
SHORTLY AFTER 9 PM THIS EVENING. OUR FORECAST GRAPHICAL TIMING
LOOKS EXCELLENT RIGHT NOW.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 343 AM EST WED DEC 23 2015
...SEVERE STORMS WITH DAMAGING WINDS POSSIBLE TONIGHT...
A RATHER ACTIVE...SPRING-LIKE PATTERN EXPECTED OVER THE NEXT 36
HOURS. PRESENTLY...A WARM FRONT IS LIFTING NORTH ACROSS TENNESSEE.
SOUTHEAST WINDS TO THE NORTH OF THE FRONT HAS KEPT MUCH OF EASTERN
KENTUCKY DRY OVERNIGHT. HOWEVER...THIS IS ABOUT TO CHANGE AS THE
FRONT CONTINUES TO PUSH NORTH THIS MORNING AND WINDS TURN MORE
SOUTHERLY. THE INITIAL SURGE OF MID LEVEL ISENTROPIC ASCENT HAS
GENERATED A LARGER POCKET OF RAINFALL OVER THE CUMBERLAND
PLATEAU...AND THIS RAIN WILL MOVE NORTH ACROSS OUR WESTERN
COUNTIES THROUGH 7 AM. INCREASED POPS TO CATEGORICAL WITH THIS
RAIN SPREADING NORTH. TO THE EAST...WE SHOULD REMAIN WITH VERY
LITTLE AS THE DOWNSLOPING CONTINUES TO EAT AWAY AT SHOWERS TRYING
TO PUSH NORTH. EVENTUALLY THE DRY AIR WILL BE OVERCOME...LIKELY
AROUND OR SHORTLY AFTER 7 AM...WITH SCATTERED SHOWERS PUSHING
NORTH ACROSS THE REGION THROUGH THE MORNING. HRRR HAS BEEN
CONSISTENT ON LINGERING SHOWERS INTO THE AFTERNOON...SO HAVE
KEPT POPS IN THE FORECAST THROUGH EARLY AFTERNOON. IT DOES APPEAR
WE SHOULD SEE A BETTER BREAK IN PRECIPITATION BY LATE AFTERNOON
THROUGH THE EARLY EVENING HOURS..AS SUBSIDENCE SPREADS IN AHEAD OF
THE APPROACHING COLD FRONT.
WITH THE FRONT APPROACHING THIS AFTERNOON...THE GRADIENT SHOULD
INCREASE AND WE WILL SEE GUSTY WINDS DEVELOP AREAWIDE. THE NAM
BUFKIT MOMENTUM TRANSFER EQUATION SUPPORTS 3O TO 35 MPH WIND
GUSTS...ESPECIALLY OUT ACROSS CENTRAL KENTUCKY...EXTENDING ACROSS
THE BLUEGRASS. WIND GUSTS UP TO 25 WILL REMAIN POSSIBLE TO THE
EAST. PUT IN A MENTION IN THE HWO OF THE GUSTY WINDS THIS
AFTERNOON.
FINALLY...MOVING ONTO THE SEVERE POTENTIAL TONIGHT. MODELS ARE
STILL NOT IN GREAT AGREEMENT ON OVERALL TIMING...AS A FEW OF THE
HI-RES MODELS SUPPORT AN EARLIER ROUND OF CONVECTION IN THE
EVENING...WHILE OTHERS HOLD OFF UNTIL OVERNIGHT. THUS...CONFIDENCE
IS HIGH ON THE THREAT FOR SEVERE STORMS OCCURRING TONIGHT...THERE
REMAINS CONSIDERABLE SPREAD ON WHETHER IT OCCURS MID TO LATE
EVENING OR AFTER MIDNIGHT. REGARDLESS OF TIMING...SHEAR GENERATED
WITH THE STRENGTH OF THE LOW LEVEL JET IS TREMENDOUS AND WILL
SUPPORT THE SEVERE STORM POTENTIAL. THE EXACT QUESTION IS HOW MUCH
INSTABILITY WILL BE PRESENT AS THE STORMS CROSS INTO EASTERN
KENTUCKY TONIGHT. NAM BUFKIT SOUNDINGS SHOW SOME POTENTIAL FOR
600-1000J/KG OF SBCAPE...WHICH IS MARGINAL...BUT COULD BE ENOUGH
TO ALLOW WINDS TO REACH THE SURFACE...ESPECIALLY IF WE END UP
DEALING WITH MORE LINE SEGMENTS. THUS...THE STORM PREDICTION
CENTER HAS EXPANDED THE ENHANCED RISK OF SEVERE STORMS INTO
CENTRAL KENTUCKY. IF WE DO END UP WITH A LINE OF STORMS
(QLCS)...A SPIN UP TORNADO WOULD ALSO BE POSSIBLE ALONG THE LINE
WITH SUCH STRONG SHEAR NEARLY NORMAL TO THE ADVANCING STORMS. WILL
CONTINUE TO HIGHLIGHT DAMAGING WINDS/TORNADO THREAT IN THE HWO AND
PLAN TO DO A MORNING WEB BRIEFING TO HIGHLIGHT THE THREAT.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 359 AM EST WED DEC 23 2015
THE MODELS REMAIN IN GOOD GENERAL AGREEMENT WITH THE AMPLIFIED AND
ACTIVE LONG WAVE PATTERN THROUGH EARLY NEXT WEEK...AS THE SUMMER-
LIKE BERMUDA HIGH VERY GRADUALLY SHIFTS TOWARDS THE BAHAMAS BY
EARLY NEXT WEEK. MEANWHILE...DEEP AND BROAD TROUGHING IN THE
WESTERN HALF OF THE NATION TRANSITIONS TO SPLIT FLOW BY THE
HOLIDAY WEEKEND. A CUTOFF LOW WILL DROP SOUTHEAST INTO
TEXAS/MEXICO...AND THEN SWING NORTHEAST INTO THE PLAINS AND
EVENTUALLY GREAT LAKES/OHIO VALLEY REGIONS BY EARLY NEXT WEEK.
NEAR RECORD TO RECORD TEMPERATURES AT TIMES...ALONG WITH SEVERAL
ROUNDS OF WET WEATHER STILL LOOK IN THE OFFING FOR THE OHIO AND
TENNESSEE VALLEYS THROUGH THE PERIOD.
A FRONTAL BOUNDARY WILL BE STALLING ACROSS OUR AREA THURSDAY
NIGHT...WITH A SURGE OF LOW LEVEL MOISTURE COMING IN BY FRIDAY
MORNING. CONFIDENCE REGARDING HOW MUCH RAINFALL WE WILL SEE
FRIDAY INTO FRIDAY NIGHT AS THE FRONTAL BOUNDARY GRADUALLY LIFTS
NORTH AS A WARM FRONT CONTINUES TO BE ON THE LOW SIDE. PWATS ARE
VERY HIGH...HOWEVER MID AND UPPER LEVEL SUPPORT IS NOT THAT
IMPRESSIVE...SO AM NOT CONVINCED THAT THE MAJORITY OF THE MOISTURE
WILL BE TAPPED DESPITE THE AMPLE LOW LEVEL JET IN PLACE. AS
SUCH...HAVE CONTINUED TO KEEP THINGS GENERALIZED CONCERNING THE
FLOOD POTENTIAL UNTIL THERE IS BETTER MODEL AGREEMENT.
THE BAROCLINIC ZONE WILL SHIFT NORTH OF OUR AREA BY LATE SATURDAY
INTO SATURDAY NIGHT...LEADING TO LESSER CHANCES OF POPS ACROSS OUR
AREA. THE MODELS HAVE BEEN WAFFLING SUNDAY INTO MONDAY...WITH THE
ECMWF SUGGESTING A NORTHERN STREAM TROUGH HAVING ENOUGH PUSH TO
SEND THE BOUNDARY BACK ACROSS OUR AREA ON SUNDAY...AND THEN
HOLDING BACK THE NEXT FRONT UNTIL MAINLY TUESDAY. THE GFS HAS A
LITTLE BETTER CONTINUITY...KEEPING THE BOUNDARY JUST TO OUR
NORTH...UNTIL THE NEXT SURGE OF MOISTURE ARRIVES MONDAY NIGHT.
GIVEN THE UNCERTAINTY...STUCK FAIRLY CLOSE TO THE BLENDED
GUIDANCE...ALTHOUGH DID LINGER POPS A BIT LONGER INTO TUESDAY TO
ALLOW FOR A POTENTIAL SLOWER EXIT.
THE BEST CHANCE TO TEST RECORD HIGHS STILL LOOK TO BE SATURDAY AND
SUNDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 654 AM EST WED DEC 23 2015
WHILE A FEW PERIODS OF MVFR CIGS WILL BE POSSIBLE THIS
MORNING...MAINLY VFR CONDITIONS SHOULD DOMINATE THE WEATHER ACROSS
EASTERN KENTUCKY TODAY. A FEW ISOLATED/SCATTERED SHOWERS WILL
REMAIN POSSIBLE THROUGH AT LEAST EARLY AFTERNOON. A LINE OF
SHOWERS AND STORMS WILL MOVE THROUGH TONIGHT...MAINLY AFTER 9
PM...PRODUCING A PERIOD OF THUNDERSTORMS AT THE TAF SITES. IN
ADDITION SOME GUSTY WINDS ARE EXPECTED THIS AFTERNOON AND EVENING
HEAD OF THIS LINE.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KAS
SHORT TERM...KAS
LONG TERM...GEOGERIAN
AVIATION...KAS
AREA FORECAST DISCUSSION
NWS NEW ORLEANS LA
900 AM CST WED DEC 23 2015
.UPDATE...
OVERALL CONVECTIVE COVERAGE HAS DECREASED THIS MORNING AS THE
REGION HAS STABALIZED A BIT IN THE WAKE OF THE RAINFALL THAT
OCCURRED EARLIER TODAY. GIVEN THIS TREND...HAVE LOWERED POPS FOR
THE FORECAST AREA THROUGH THE EARLY AFTERNOON HOURS INTO THE
CHANCE RANGE FROM CATEGORICAL. HOWEVER...ANOTHER ROUND OF
CONVECTIVE DEVELOPMENT STILL LOOKS LIKELY FROM MID-AFTERNOON
THROUGH THE EVENING HOURS AS THE ATMOSPHERE WARMS AND TURNS MORE
UNSTABLE. ADDITIONALLY...ANOTHER UPPER LEVEL IMPULSE OF INCREASED
VORTICITY AND OMEGA WILL SLIDE THROUGH THE LOWER MISSISSIPPI
VALLEY DURING THE AFTERNOON HOURS. THIS INCREASE IN LIFT ALOFT
SHOULD PROVIDE ENOUGH OF A CATALYST TO FIRE OFF ANOTHER ROUND OF
SHOWERS AND THUNDERSTORMS. HAVE LIKELY POPS IN PLACE FOR THE LATE
AFTERNOON AND EVENING HOURS TO REFLECT THIS RISK. OUTSIDE OF THE
POP ADJUSTMENTS...NO OTHER FORECAST CHANGES WERE MADE AT THIS
TIME. 32
&&
.PREV DISCUSSION... /ISSUED 758 AM CST WED DEC 23 2015/
..SOUNDING DISCUSSION...
BOTTOM LINE UP FRONT...ALL MODES OF SEVERE WEATHER REMAIN POSSIBLE
TODAY. A VERY MOIST ATMOSPHERE WAS SAMPLED THIS MORNING WITH A
PRECIPITABLE WATER VALUE OF 1.74 INCHES. THIS IS 2 STANDARD
DEVIATIONS ABOVE NORMAL AND A RECORD VALUE FOR THIS DATE/TIME.
MOST UNSTABLE CAPE OF ABOUT 1200 J/KG EXISTS WITH INHIBITION IN
THE FORM OF A CAPPING INVERSION. ASSUMING LOW CLOUDS AND FOG
DISSIPATE AND WE HAVE SOME SURFACE HEATING...THIS CAPPING
INVERSION SHOULD ERODE. WITH QUITE A BIT OF MOISTURE IN THE LOW-
LEVELS...THE DOWNDRAFT CAPE IS NOT IN THE OPTIMUM RANGE FOR
DAMAGING STRAIGHT LINE WINDS. THIS MAY CHANGE IF DRIER AIR MIXES
DOWN AND WINDS BECOME MORE UNIDIRECTIONAL. THE FREEZING LEVEL IS
NEAR 13000 FEET WHICH IS HIGH...BUT THERE WAS A REPORT EARLIER IN
THE NIGHT OF 1.25 INCH DIAMETER HAIL IN ASCENSION PARISH. 0-1KM
SRH AND 0-3KM SRH IS IMPRESSIVE AT 200 AND 340 M2/S2 RESPECTIVELY.
WINDS ARE FROM THE SOUTHEAST AT THE SURFACE AND THEN ARE
PREDOMINATELY FROM THE SOUTHWEST. SO THERE IS LOW LEVEL
DIRECTIONAL SHEAR CURRENTLY. THERE IS ALSO SOME SPEED SHEAR WITH
950MB AT 15 KNOTS...850MB AT 33 KNOTS...700MB AT 51 KNOTS...500MB
IS AT 58 KNOTS. A PEAK WIND SPEED OF 103 KNOTS WAS AT 39000 FEET
WITH A STORM TOP WIND SPEED NEAR 48000 FEET OF 72 KNOTS.
SPC HAS REQUESTED AN 18Z SOUNDING IN SUPPORT OF SEVERE WEATHER
OPERATIONS.
12Z BALLOON INFO: A SUCCESSFUL FLIGHT LASTING 85 MINUTES AND
REACHING A HEIGHT OF 14.8 MILES ABOVE THE GROUND. THE BALLOON
BURST OVER NEELY 84 MILES DOWNRANGE FROM THE OFFICE.
ANSORGE
PREV DISCUSSION... /ISSUED 406 AM CST WED DEC 23 2015/
SHORT TERM... ACTIVE CONDITIONS ONGOING ACROSS THE FORECAST AREA
THIS MORNING. LOCAL VAD WIND PROFILE SHOWS THAT LOW LEVEL WINDS HAVE
INCREASES SUBSTANTIALLY OVER THE LAST FEW HOURS WITH SE FLOW OF 30
KNOTS AT THE LOWEST OBS OF 1KFT AND VEERING TO SW WHILE INCREASING
TO 50KTS IN THE MID LEVELS. THIS IS THE PRIMARY REASON FOR THE
RECENT RAMP UP OF STRONG/SEVERE THUNDERSTORMS EARLY THIS MORNING.
HAVE RECEIVED 1 REPORT OF HAIL AND SEVERAL CELLS HAVE BROAD
ROTATION...INDICATIVE OF INCREASING SRH. THIS IS ALL HAPPENING
DESPITE BEING WITHIN A MARINE LAYER. THE TREND OF ACTIVE WEATHER
WITH THE POTENTIAL FOR A FEW CELLS PRODUCING HAIL OR A TORNADO WILL
CONTINUE THROUGH THE REST OF THE EARLY MORNING HOURS. THE BULK OF
STRONGER STORMS WILL SHIFT NORTHEAST AFTER SUNRISE AS SHORT WAVE
VORTMAX DOES SO AS WELL.
MOISTURE LEVELS REMAIN VERY HIGH ACROSS THE CENTRAL GULF COAST THIS
MORNING WITH THE 00Z SOUNDING FROM YESTERDAY AFTERNOON HAVING A
PRECIP WATER VALUE OF AROUND 1.7 INCHES WHICH IS RIGHT AT THE
CLIMATOLOGY MAX PER SPC SOUNDING INFO. BROAD LONG WAVE TROUGH IS
ALREADY IN PLACE OVER THE WESTERN HALF OF THE COUNTRY. AN EMBEDDED
WAVE WILL DIG AND SWING NEGATIVE OVER THE CENTRAL PLAINS TODAY. DOWN
AT THE SURFACE A LOW ON THE LEESIDE OF THE ROCKIES WILL BE RACING
NORTHEAST ACROSS THE CENTRAL MISSISSIPPI VALLEY. SURFACE PRESSURES
IN THE CWA WILL BE SLOWLY FALLING DURING THE DAY WITH A MINIMUM OF
APPROACHING 1000MB BY NOON BASED ON RUC OUTPUT. TIGHTENING OF THE
PRESSURE GRADIENT WILL INCREASE SURFACE WINDS INTO THE 15 TO 25
MPH RANGE. THIS SHOULD DO 2 THINGS...TRANSPORT OFFSHORE 70+DEGREE
DEWPOINTS FURTHER INLAND AS WELL AS INCREASE LOW LEVEL WIND SHEAR
SUBSTANTIALLY. HELICITY LIKELY TO FALL SOME AS WIND DIRECTION
BECOMES MORE CLOSELY ORIENTED TO THE MEAN FLOW OR MORE SOUTH TO
SOUTH WEST RATHER THAN CURRENT SOUTHEAST DIRECTION. PRESUMING THAT
SFC TEMPS DO REACH MID/UPPER 70S WHILE THESE DEWPOINTS
RISE...BUOYANCY AND INSTABILITY WILL SHOOT UP DURING THE DAY. BOTH
GFS AND NAM BUFR SOUNDINGS STILL SHOW SB AND PARCEL CAPE VALUES
WELL OVER 2000 J/KG AND MU CAPE UP TO 1500 J/KG ALL OVER THE CWA.
SPEED SHEAR LOOKING TO BE 40 TO 50 KNOTS IN THE BOUNDARY LAYER
WHICH IS PLENTY STRONG TO SUSTAIN SUPERCELLS. THUS THE POTENTIAL
FOR SEVERE WEATHER WILL DEFINITELY BE THERE TODAY. ALL MODES OF
SEVERE WEATHER ARE POSSIBLE. STILL OF CONCERN IS IF SFC TEMPS DONT
WARM ENOUGH... WILL JUST HAVE THE DYNAMICS. TOO STRONG OF A WARM
NOSE IN THE LOWER LEVELS COULD CAP THINGS AS WELL REGARDLESS...THE
POTENTIAL IS DEFINITELY THERE AND WARRANTS THE SLIGHT RISK AT THE
LEAST FOR THE ENTIRE CWA.
LONG TERM... RESIDUAL SURFACE BOUNDARY WILL BE THE FOCUS FOR
CONVECTION ON THURSDAY. AMPLE MOISTURE STILL LEFT IN THE AREA SHOULD
HAVE NO PROBLEM DEVELOPING INTO SHOWERS WITH POSSIBLY A FEW
THUNDERSTORMS. MUCH WEAKER WINDS IN THE COLUMN WILL LIMIT
ORGANIZATION OF STORMS BUT WONT BE SHORT OF INSTABILITY.
COVERAGE SHOULD STILL BE 50 TO 70 PERCENT FOR THE MOST PART.
CHRISTMAS DAY SHOULD BEGIN THE DOWNWARD TREND OF POPS AS UPPER LEVEL
RIDGE CENTERED OVER THE WESTERN ATLANTIC BUILDS BACK WESTWARD ACROSS
THE CWA. DESPITE THIS DECREASE IN COVERAGE...STILL PROBABLY LOOKING
AT 20 TO 30 PERCENT RAIN CHANCE. NO CHANCE IN THE TEMP FORECAST AND
EXPECTING NEAR RECORD MAX TEMPS AND RECORD HIGH LOWS. SADLY...THERE
IS A ZERO PERCENT CHANCE FOR A WHITE CHRISTMAS.
POPS TO FALL EVEN MORE DOWN INTO THE SLIGHT CHANCE CATEGORY THIS
WEEKEND AS THE RIDGE SHIFTS THE SHEAR ZONE FURTHER NORTH AND WEST.
GFS AND ECMWF BOTH CLOSE OFF A LOW IN THE DESERT SOUTHWEST AND
TRACKS EAST BEFORE SWINGING NE OVER THE CENTRAL PLAINS ENDING THE
WEEKEND. THIS WOULD BRING A LINE OF SHOWERS AND STORMS MOVING THRU
SOME TIME BETWEEN SUNDAY NIGHT AND MONDAY NIGHT DEPENDING ON MODEL
TIMING. NUDGED THE POPS TO THE SLOWER SOLUTION AS THE FASTER GFS IS
CLOSER TO AN OUTLIER SIDE OF THINGS.
MEFFER
AVIATION... SEVERE WEATHER CAME IN A LITTLE EARLIER TODAY THAN
EXPECTED. WILL KEEP THAT THREAT GOING THROUGH THE DAY BUT EXPECT A
REPRIEVE FOR SEVERAL HOURS AFTER DAYLIGHT TODAY. ANOTHER ROUND WILL
BE POSSIBLE THIS AFTERNOON BUT WILL HAVE TO SEE HOW THIS SHAPES UP.
CEILINGS WILL REMAIN FROM OVC020 TO OVC030 TODAY AND TONIGHT. RAIN
WILL ALSO CEASE FOR A WHILE TODAY AND WILL SHOW THIS IN THE 12Z TAF
PACKAGE.
WILL TAKE ANOTHER LOOK AT WX IN TAF SET LATER THIS MORNING.
MARINE... AS UPPER SYSTEM SWINGS THROUGH THE MIDDLE MISSISSIPPI
RIVER VALLEY TODAY...PRESSURE GRADIENT WILL TIGHTEN AND SMALL CRAFT
ADVISORIES AND EXERCISE CAUTION HEADLINES HAVE BEEN ISSUED AHEAD OF
THE SYSTEM. THIS SHOULD BE SOMEWHAT SHORT LIVED AS WINDS SUBSIDE
TONIGHT. NEXT PERIOD OF HEADLINES WILL BE EXERCISE CAUTION HEADLINES
OVER THE WEEKEND AS ONSHORE FLOW AGAIN STRENGTHENS.
DECISION SUPPORT...
DSS CODE....BLUE.
DEPLOYED...NONE.
ACTIVATION...NONE.
ACTIVITIES...MONITORING CONVECTIVE TRENDS.
DECISION SUPPORT SERVICES (DSS) CODE LEGEND
GREEN = NO WEATHER IMPACTS THAT REQUIRE ACTION
BLUE = LONG FUSED WATCH/WARNING/ADVISORY IN EFFECT OR HIGH
VISIBILITY EVENT
YELLOW = HEIGHTENED IMPACTS WITH SHORT FUSED WATCH/WARNING/ADVISORY
ISSUANCES; RADAR SUPPORT
ORANGE = HIGH IMPACTS - SLIGHT TO MODERATE RISK SEVERE; NEARBY
TROPICAL EVENTS; HAZMAT OR OTHER LARGE EPISODES
RED = FULL ENGAGEMENT FOR MODERATE RISK SVR AND/OR DIRECT
TROPICAL THREATS; EVENTS OF NATIONAL SIGNIFICANCE
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 78 64 77 68 / 90 70 60 40
BTR 79 65 79 70 / 80 70 50 30
ASD 75 67 76 68 / 90 70 70 30
MSY 78 69 76 69 / 80 70 70 30
GPT 73 68 74 68 / 90 70 70 30
PQL 74 69 74 68 / 80 70 70 30
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 6 PM CST THIS EVENING FOR GMZ536-538-
550-552-555-557-570-572-575-577.
MS...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 6 PM CST THIS EVENING FOR GMZ538-550-
552-555-557-570-572-575-577.
&&
$$
AREA FORECAST DISCUSSION
NWS NEW ORLEANS LA
758 AM CST WED DEC 23 2015
...SOUNDING DISCUSSION...
BOTTOM LINE UP FRONT...ALL MODES OF SEVERE WEATHER REMAIN POSSIBLE
TODAY. A VERY MOIST ATMOSPHERE WAS SAMPLED THIS MORNING WITH A
PRECIPITABLE WATER VALUE OF 1.74 INCHES. THIS IS 2 STANDARD
DEVIATIONS ABOVE NORMAL AND A RECORD VALUE FOR THIS DATE/TIME.
MOST UNSTABLE CAPE OF ABOUT 1200 J/KG EXISTS WITH INHIBITION IN
THE FORM OF A CAPPING INVERSION. ASSUMING LOW CLOUDS AND FOG
DISSIPATE AND WE HAVE SOME SURFACE HEATING...THIS CAPPING
INVERSION SHOULD ERODE. WITH QUITE A BIT OF MOISTURE IN THE LOW-
LEVELS...THE DOWNDRAFT CAPE IS NOT IN THE OPTIMUM RANGE FOR
DAMAGING STRAIGHT LINE WINDS. THIS MAY CHANGE IF DRIER AIR MIXES
DOWN AND WINDS BECOME MORE UNIDIRECTIONAL. THE FREEZING LEVEL IS
NEAR 13000 FEET WHICH IS HIGH...BUT THERE WAS A REPORT EARLIER IN
THE NIGHT OF 1.25 INCH DIAMETER HAIL IN ASCENSION PARISH. 0-1KM
SRH AND 0-3KM SRH IS IMPRESSIVE AT 200 AND 340 M2/S2 RESPECTIVELY.
WINDS ARE FROM THE SOUTHEAST AT THE SURFACE AND THEN ARE
PREDOMINATELY FROM THE SOUTHWEST. SO THERE IS LOW LEVEL
DIRECTIONAL SHEAR CURRENTLY. THERE IS ALSO SOME SPEED SHEAR WITH
950MB AT 15 KNOTS...850MB AT 33 KNOTS...700MB AT 51 KNOTS...500MB
IS AT 58 KNOTS. A PEAK WIND SPEED OF 103 KNOTS WAS AT 39000 FEET
WITH A STORM TOP WIND SPEED NEAR 48000 FEET OF 72 KNOTS.
SPC HAS REQUESTED AN 18Z SOUNDING IN SUPPORT OF SEVERE WEATHER
OPERATIONS.
12Z BALLOON INFO: A SUCCESSFUL FLIGHT LASTING 85 MINUTES AND
REACHING A HEIGHT OF 14.8 MILES ABOVE THE GROUND. THE BALLOON
BURST OVER NEELY 84 MILES DOWNRANGE FROM THE OFFICE.
ANSORGE
&&
.PREV DISCUSSION... /ISSUED 406 AM CST WED DEC 23 2015/
SHORT TERM... ACTIVE CONDITIONS ONGOING ACROSS THE FORECAST AREA
THIS MORNING. LOCAL VAD WIND PROFILE SHOWS THAT LOW LEVEL WINDS HAVE
INCREASES SUBSTANTIALLY OVER THE LAST FEW HOURS WITH SE FLOW OF 30
KNOTS AT THE LOWEST OBS OF 1KFT AND VEERING TO SW WHILE INCREASING
TO 50KTS IN THE MID LEVELS. THIS IS THE PRIMARY REASON FOR THE
RECENT RAMP UP OF STRONG/SEVERE THUNDERSTORMS EARLY THIS MORNING.
HAVE RECEIVED 1 REPORT OF HAIL AND SEVERAL CELLS HAVE BROAD
ROTATION...INDICATIVE OF INCREASING SRH. THIS IS ALL HAPPENING
DESPITE BEING WITHIN A MARINE LAYER. THE TREND OF ACTIVE WEATHER
WITH THE POTENTIAL FOR A FEW CELLS PRODUCING HAIL OR A TORNADO WILL
CONTINUE THROUGH THE REST OF THE EARLY MORNING HOURS. THE BULK OF
STRONGER STORMS WILL SHIFT NORTHEAST AFTER SUNRISE AS SHORT WAVE
VORTMAX DOES SO AS WELL.
MOISTURE LEVELS REMAIN VERY HIGH ACROSS THE CENTRAL GULF COAST THIS
MORNING WITH THE 00Z SOUNDING FROM YESTERDAY AFTERNOON HAVING A
PRECIP WATER VALUE OF AROUND 1.7 INCHES WHICH IS RIGHT AT THE
CLIMATOLOGY MAX PER SPC SOUNDING INFO. BROAD LONG WAVE TROUGH IS
ALREADY IN PLACE OVER THE WESTERN HALF OF THE COUNTRY. AN EMBEDDED
WAVE WILL DIG AND SWING NEGATIVE OVER THE CENTRAL PLAINS TODAY. DOWN
AT THE SURFACE A LOW ON THE LEESIDE OF THE ROCKIES WILL BE RACING
NORTHEAST ACROSS THE CENTRAL MISSISSIPPI VALLEY. SURFACE PRESSURES
IN THE CWA WILL BE SLOWLY FALLING DURING THE DAY WITH A MINIMUM OF
APPROACHING 1000MB BY NOON BASED ON RUC OUTPUT. TIGHTENING OF THE
PRESSURE GRADIENT WILL INCREASE SURFACE WINDS INTO THE 15 TO 25
MPH RANGE. THIS SHOULD DO 2 THINGS...TRANSPORT OFFSHORE 70+DEGREE
DEWPOINTS FURTHER INLAND AS WELL AS INCREASE LOW LEVEL WIND SHEAR
SUBSTANTIALLY. HELICITY LIKELY TO FALL SOME AS WIND DIRECTION
BECOMES MORE CLOSELY ORIENTED TO THE MEAN FLOW OR MORE SOUTH TO
SOUTH WEST RATHER THAN CURRENT SOUTHEAST DIRECTION. PRESUMING THAT
SFC TEMPS DO REACH MID/UPPER 70S WHILE THESE DEWPOINTS
RISE...BUOYANCY AND INSTABILITY WILL SHOOT UP DURING THE DAY. BOTH
GFS AND NAM BUFR SOUNDINGS STILL SHOW SB AND PARCEL CAPE VALUES
WELL OVER 2000 J/KG AND MU CAPE UP TO 1500 J/KG ALL OVER THE CWA.
SPEED SHEAR LOOKING TO BE 40 TO 50 KNOTS IN THE BOUNDARY LAYER
WHICH IS PLENTY STRONG TO SUSTAIN SUPERCELLS. THUS THE POTENTIAL
FOR SEVERE WEATHER WILL DEFINITELY BE THERE TODAY. ALL MODES OF
SEVERE WEATHER ARE POSSIBLE. STILL OF CONCERN IS IF SFC TEMPS DONT
WARM ENOUGH... WILL JUST HAVE THE DYNAMICS. TOO STRONG OF A WARM
NOSE IN THE LOWER LEVELS COULD CAP THINGS AS WELL REGARDLESS...THE
POTENTIAL IS DEFINITELY THERE AND WARRANTS THE SLIGHT RISK AT THE
LEAST FOR THE ENTIRE CWA.
LONG TERM... RESIDUAL SURFACE BOUNDARY WILL BE THE FOCUS FOR
CONVECTION ON THURSDAY. AMPLE MOISTURE STILL LEFT IN THE AREA SHOULD
HAVE NO PROBLEM DEVELOPING INTO SHOWERS WITH POSSIBLY A FEW
THUNDERSTORMS. MUCH WEAKER WINDS IN THE COLUMN WILL LIMIT
ORGANIZATION OF STORMS BUT WONT BE SHORT OF INSTABILITY.
COVERAGE SHOULD STILL BE 50 TO 70 PERCENT FOR THE MOST PART.
CHRISTMAS DAY SHOULD BEGIN THE DOWNWARD TREND OF POPS AS UPPER LEVEL
RIDGE CENTERED OVER THE WESTERN ATLANTIC BUILDS BACK WESTWARD ACROSS
THE CWA. DESPITE THIS DECREASE IN COVERAGE...STILL PROBABLY LOOKING
AT 20 TO 30 PERCENT RAIN CHANCE. NO CHANCE IN THE TEMP FORECAST AND
EXPECTING NEAR RECORD MAX TEMPS AND RECORD HIGH LOWS. SADLY...THERE
IS A ZERO PERCENT CHANCE FOR A WHITE CHRISTMAS.
POPS TO FALL EVEN MORE DOWN INTO THE SLIGHT CHANCE CATEGORY THIS
WEEKEND AS THE RIDGE SHIFTS THE SHEAR ZONE FURTHER NORTH AND WEST.
GFS AND ECMWF BOTH CLOSE OFF A LOW IN THE DESERT SOUTHWEST AND
TRACKS EAST BEFORE SWINGING NE OVER THE CENTRAL PLAINS ENDING THE
WEEKEND. THIS WOULD BRING A LINE OF SHOWERS AND STORMS MOVING THRU
SOME TIME BETWEEN SUNDAY NIGHT AND MONDAY NIGHT DEPENDING ON MODEL
TIMING. NUDGED THE POPS TO THE SLOWER SOLUTION AS THE FASTER GFS IS
CLOSER TO AN OUTLIER SIDE OF THINGS.
MEFFER
AVIATION... SEVERE WEATHER CAME IN A LITTLE EARLIER TODAY THAN
EXPECTED. WILL KEEP THAT THREAT GOING THROUGH THE DAY BUT EXPECT A
REPRIEVE FOR SEVERAL HOURS AFTER DAYLIGHT TODAY. ANOTHER ROUND WILL
BE POSSIBLE THIS AFTERNOON BUT WILL HAVE TO SEE HOW THIS SHAPES UP.
CEILINGS WILL REMAIN FROM OVC020 TO OVC030 TODAY AND TONIGHT. RAIN
WILL ALSO CEASE FOR A WHILE TODAY AND WILL SHOW THIS IN THE 12Z TAF
PACKAGE.
WILL TAKE ANOTHER LOOK AT WX IN TAF SET LATER THIS MORNING.
MARINE... AS UPPER SYSTEM SWINGS THROUGH THE MIDDLE MISSISSIPPI
RIVER VALLEY TODAY...PRESSURE GRADIENT WILL TIGHTEN AND SMALL CRAFT
ADVISORIES AND EXERCISE CAUTION HEADLINES HAVE BEEN ISSUED AHEAD OF
THE SYSTEM. THIS SHOULD BE SOMEWHAT SHORT LIVED AS WINDS SUBSIDE
TONIGHT. NEXT PERIOD OF HEADLINES WILL BE EXERCISE CAUTION HEADLINES
OVER THE WEEKEND AS ONSHORE FLOW AGAIN STRENGTHENS.
DECISION SUPPORT...
DSS CODE....BLUE.
DEPLOYED...NONE.
ACTIVATION...NONE.
ACTIVITIES...MONITORING CONVECTIVE TRENDS.
DECISION SUPPORT SERVICES (DSS) CODE LEGEND
GREEN = NO WEATHER IMPACTS THAT REQUIRE ACTION
BLUE = LONG FUSED WATCH/WARNING/ADVISORY IN EFFECT OR HIGH
VISIBILITY EVENT
YELLOW = HEIGHTENED IMPACTS WITH SHORT FUSED WATCH/WARNING/ADVISORY
ISSUANCES; RADAR SUPPORT
ORANGE = HIGH IMPACTS - SLIGHT TO MODERATE RISK SEVERE; NEARBY
TROPICAL EVENTS; HAZMAT OR OTHER LARGE EPISODES
RED = FULL ENGAGEMENT FOR MODERATE RISK SVR AND/OR DIRECT
TROPICAL THREATS; EVENTS OF NATIONAL SIGNIFICANCE
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 78 64 77 68 / 90 30 60 40
BTR 79 65 79 70 / 80 30 50 30
ASD 75 67 76 68 / 90 40 70 30
MSY 78 69 76 69 / 80 40 70 30
GPT 73 68 74 68 / 90 50 70 30
PQL 74 69 74 68 / 80 60 70 30
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 6 PM CST THIS EVENING FOR GMZ536-538-
550-552-555-557-570-572-575-577.
MS...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 6 PM CST THIS EVENING FOR GMZ538-550-
552-555-557-570-572-575-577.
&&
$$
AREA FORECAST DISCUSSION
NWS NEW ORLEANS LA
406 AM CST WED DEC 23 2015
.SHORT TERM... ACTIVE CONDITIONS ONGOING ACROSS THE FORECAST AREA
THIS MORNING. LOCAL VAD WIND PROFILE SHOWS THAT LOW LEVEL WINDS HAVE
INCREASES SUBSTANTIALLY OVER THE LAST FEW HOURS WITH SE FLOW OF 30
KNOTS AT THE LOWEST OBS OF 1KFT AND VEERING TO SW WHILE INCREASING
TO 50KTS IN THE MID LEVELS. THIS IS THE PRIMARY REASON FOR THE
RECENT RAMP UP OF STRONG/SEVERE THUNDERSTORMS EARLY THIS MORNING.
HAVE RECEIVED 1 REPORT OF HAIL AND SEVERAL CELLS HAVE BROAD
ROTATION...INDICATIVE OF INCREASING SRH. THIS IS ALL HAPPENING
DESPITE BEING WITHIN A MARINE LAYER. THE TREND OF ACTIVE WEATHER
WITH THE POTENTIAL FOR A FEW CELLS PRODUCING HAIL OR A TORNADO WILL
CONTINUE THROUGH THE REST OF THE EARLY MORNING HOURS. THE BULK OF
STRONGER STORMS WILL SHIFT NORTHEAST AFTER SUNRISE AS SHORT WAVE
VORTMAX DOES SO AS WELL.
MOISTURE LEVELS REMAIN VERY HIGH ACROSS THE CENTRAL GULF COAST THIS
MORNING WITH THE 00Z SOUNDING FROM YESTERDAY AFTERNOON HAVING A
PRECIP WATER VALUE OF AROUND 1.7 INCHES WHICH IS RIGHT AT THE
CLIMATOLOGY MAX PER SPC SOUNDING INFO. BROAD LONG WAVE TROUGH IS
ALREADY IN PLACE OVER THE WESTERN HALF OF THE COUNTRY. AN EMBEDDED
WAVE WILL DIG AND SWING NEGATIVE OVER THE CENTRAL PLAINS TODAY. DOWN
AT THE SURFACE A LOW ON THE LEESIDE OF THE ROCKIES WILL BE RACING
NORTHEAST ACROSS THE CENTRAL MISSISSIPPI VALLEY. SURFACE PRESSURES
IN THE CWA WILL BE SLOWLY FALLING DURING THE DAY WITH A MINIMUM OF
APPROACHING 1000MB BY NOON BASED ON RUC OUTPUT . TIGHTENING OF THE
PRESSURE GRADIENT WILL INCREASE SURFACE WINDS INTO THE 15 TO 25 MPH
RANGE. THIS SHOULD DO 2 THINGS...TRANSPORT OFFSHORE 70+DEGREE
DEWPOINTS FURTHER INLAND AS WELL AS INCREASE LOW LEVEL WIND SHEAR
SUBSTANTIALLY. HELICITY LIKELY TO FALL SOME AS WIND DIRECTION
BECOMES MORE CLOSELY ORIENTED TO THE MEAN FLOW OR MORE SOUTH TO
SOUTH WEST RATHER THAN CURRENT SOUTHEAST DIRECTION. PRESUMING THAT
SFC TEMPS DO REACH MID/UPPER 70S WHILE THESE DEWPOINTS
RISE...BUOYANCY AND INSTABILITY WILL SHOOT UP DURING THE DAY. BOTH
GFS AND NAM BUFR SOUNDINGS STILL SHOW SB AND PARCEL CAPE VALUES WELL
OVER 2000 J/KG AND MU CAPE UP TO 1500 J/KG ALL OVER THE CWA. SPEED
SHEAR LOOKING TO BE 40 TO 50 KNOTS IN THE BOUNDARY LAYER WHICH IS
PLENTY STRONG TO SUSTAIN SUPERCELLS. THUS THE POTENTIAL FOR SEVERE
WEATHER WILL DEFINITELY BE THERE TODAY. ALL MODES OF SEVERE WEATHER
ARE POSSIBLE. STILL OF CONCERN IS IF SFC TEMPS DONT WARM ENOUGH...
WILL JUST HAVE THE DYNAMICS. TOO STRONG OF A WARM NOSE IN THE LOWER
LEVELS COULD CAP THINGS AS WELL REGARDLESS...THE POTENTIAL IS
DEFINITELY THERE AND WARRANTS THE SLIGHT RISK AT THE LEAST FOR THE
ENTIRE CWA.
.LONG TERM... RESIDUAL SURFACE BOUNDARY WILL BE THE FOCUS FOR
CONVECTION ON THURSDAY. AMPLE MOISTURE STILL LEFT IN THE AREA SHOULD
HAVE NO PROBLEM DEVELOPING INTO SHOWERS WITH POSSIBLY A FEW
THUNDERSTORMS. MUCH WEAKER WINDS IN THE COLUMN WILL LIMIT
ORGANIZATION OF STORMS BUT WONT BE SHORT OF INSTABILITY.
COVERAGE SHOULD STILL BE 50 TO 70 PERCENT FOR THE MOST PART.
CHRISTMAS DAY SHOULD BEGIN THE DOWNWARD TREND OF POPS AS UPPER LEVEL
RIDGE CENTERED OVER THE WESTERN ATLANTIC BUILDS BACK WESTWARD ACROSS
THE CWA. DESPITE THIS DECREASE IN COVERAGE...STILL PROBABLY LOOKING
AT 20 TO 30 PERCENT RAIN CHANCE. NO CHANCE IN THE TEMP FORECAST AND
EXPECTING NEAR RECORD MAX TEMPS AND RECORD HIGH LOWS. SADLY...THERE
IS A ZERO PERCENT CHANCE FOR A WHITE CHRISTMAS.
POPS TO FALL EVEN MORE DOWN INTO THE SLIGHT CHANCE CATEGORY THIS
WEEKEND AS THE RIDGE SHIFTS THE SHEAR ZONE FURTHER NORTH AND WEST.
GFS AND ECMWF BOTH CLOSE OFF A LOW IN THE DESERT SOUTHWEST AND
TRACKS EAST BEFORE SWINGING NE OVER THE CENTRAL PLAINS ENDING THE
WEEKEND. THIS WOULD BRING A LINE OF SHOWERS AND STORMS MOVING THRU
SOME TIME BETWEEN SUNDAY NIGHT AND MONDAY NIGHT DEPENDING ON MODEL
TIMING. NUDGED THE POPS TO THE SLOWER SOLUTION AS THE FASTER GFS IS
CLOSER TO AN OUTLIER SIDE OF THINGS.
MEFFER
&&
.AVIATION... SEVERE WEATHER CAME IN A LITTLE EARLIER TODAY THAN
EXPECTED. WILL KEEP THAT THREAT GOING THROUGH THE DAY BUT EXPECT A
REPRIEVE FOR SEVERAL HOURS AFTER DAYLIGHT TODAY. ANOTHER ROUND WILL
BE POSSIBLE THIS AFTERNOON BUT WILL HAVE TO SEE HOW THIS SHAPES UP.
CEILINGS WILL REMAIN FROM OVC020 TO OVC030 TODAY AND TONIGHT. RAIN
WILL ALSO CEASE FOR A WHILE TODAY AND WILL SHOW THIS IN THE 12Z TAF
PACKAGE.
WILL TAKE ANOTHER LOOK AT WX IN TAF SET LATER THIS MORNING.
&&
.MARINE... AS UPPER SYSTEM SWINGS THROUGH THE MIDDLE MISSISSIPPI
RIVER VALLEY TODAY...PRESSURE GRADIENT WILL TIGHTEN AND SMALL CRAFT
ADVISORIES AND EXERCISE CAUTION HEADLINES HAVE BEEN ISSUED AHEAD OF
THE SYSTEM. THIS SHOULD BE SOMEWHAT SHORT LIVED AS WINDS SUBSIDE
TONIGHT. NEXT PERIOD OF HEADLINES WILL BE EXERCISE CAUTION HEADLINES
OVER THE WEEKEND AS ONSHORE FLOW AGAIN STRENGTHENS.
&&
DECISION SUPPORT...
DSS CODE....BLUE.
DEPLOYED...NONE.
ACTIVATION...NONE.
ACTIVITIES...MONITORING CONVECTIVE TRENDS. MARGINAL TONIGHT...SLIGHT WED.
DECISION SUPPORT SERVICES (DSS) CODE LEGEND
GREEN = NO WEATHER IMPACTS THAT REQUIRE ACTION
BLUE = LONG FUSED WATCH/WARNING/ADVISORY IN EFFECT OR HIGH
VISIBILITY EVENT
YELLOW = HEIGHTENED IMPACTS WITH SHORT FUSED WATCH/WARNING/ADVISORY
ISSUANCES; RADAR SUPPORT
ORANGE = HIGH IMPACTS - SLIGHT TO MODERATE RISK SEVERE; NEARBY
TROPICAL EVENTS; HAZMAT OR OTHER LARGE EPISODES
RED = FULL ENGAGEMENT FOR MODERATE RISK SVR AND/OR DIRECT
TROPICAL THREATS; EVENTS OF NATIONAL SIGNIFICANCE
&&
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 78 64 77 68 / 90 30 60 40
BTR 79 65 79 70 / 80 30 50 30
ASD 75 67 76 68 / 90 40 70 30
MSY 78 69 76 69 / 80 40 70 30
GPT 73 68 74 68 / 90 50 70 30
PQL 74 69 74 68 / 80 60 70 30
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 6 PM CST THIS EVENING FOR GMZ536-538-
550-552-555-557-570-572-575-577.
MS...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 6 PM CST THIS EVENING FOR GMZ538-550-
552-555-557-570-572-575-577.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS DULUTH MN
915 AM CST WED DEC 23 2015
.UPDATE...
ISSUED AT 915 AM CST WED DEC 23 2015
UPDATED WEATHER TYPES FOR TODAY THROUGH 00Z. HAVE HAD REPORTS THIS
MORNING OF SLEET/RAIN MIX IN SOUTHERN WASHBURN COUNTY AND A
SNOW/RAIN MIX IN HAYWARD IN THE PAST FEW HOURS. STILL THINKING THE
COLUMN WILL COOL AND TREND TOWARD BETTER ICE CRYSTAL SEEDING
THROUGH THIS MORNING AS PRECIP RATES INCREASE...RESULTING IN
BETTER SNOW COVERAGE. HAVE INCLUDED A BIT MORE SLEET AND A
BROADER AREA OF RA/SN THROUGH THIS MORNING AND INTO THE AFTERNOON.
ALSO INCREASED COVERAGE OF DZ/FZDZ THROUGHOUT THE DAY IN AREAS NOT
EXPERIENCING THE HEAVIER PRECIPITATION. ALSO THREW IN A MENTION OF
FOG WHICH HAS BEEN OBSERVED AT SEVERAL SITES THIS MORNING.
UPDATE ISSUED AT 630 AM CST WED DEC 23 2015
MINOR UPDATE TO POPS AND WEATHER...IN GENERAL FORECAST REMAINS ON
TRACK WITH A LIGHT WINTRY MIX QUICKLY CHANGING TO MAINLY SNOW
WEST OF HIGHWAY 63 IN NW WISCONSIN AND MORE RAIN THAN SNOW EAST OF
HIGHWAY 63.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 427 AM CST WED DEC 23 2015
RAIN/SNOW WILL QUICKLY SPREAD ACROSS NORTHWEST WISCONSIN AND PARTS
OF NORTHEAST MINNESOTA TODAY RESULTING IN A QUICK FEW INCHES OF SNOW
FOR PARTS OF THE REGION. WHERE THE RAIN/SNOW LINE WILL BE IS STILL
DIFFICULT TO DETERMINE EVEN AT THIS SHORT TIME RANGE...BUT
CONFIDENCE HAS INCREASED IN COVERAGE OF PRECIPITATION /TRENDING
FARTHER WEST/ INTENSITY /HIGHER AMOUNTS/ AND RANGE OF PRECIP TYPES
EXPECTED /MAINLY JUST RAIN OR SNOW WITH LITTLE MIX/. RAIN/SNOW ENDS
QUICKLY FROM WEST TO EAST LATE TONIGHT WITH LINGERING FLURRIES
POSSIBLE INTO EARLY THURSDAY. WHEN IT IS ALL DONE THERE WILL LIKELY
BE A SWATH OF 2 TO 4 INCHES OF SNOW ACROSS A PORTION OF NORTHWEST
WISCONSIN...WITH OTHER LOCATIONS EXPERIENCE MAINLY RAIN ENDING AS
LIGHT SNOW.
ON THE SYNOPTIC SCALE A MID-LEVEL TROUGH AXIS WILL SWING NORTHEAST
FROM THE LOWER MISSOURI RIVER VALLEY INTO THE UPPER GREAT LAKES
TODAY. WHILE A POTENT LOW PRESSURE SYSTEM OVER THE RED RIVER VALLEY
MOVES NORTH INTO NORTHWEST ONTARIO IT WILL WEAKEN WHILE A STRONG AND
BROADER LOW PRESSURE DEVELOPS IN NORTHERN MISSOURI LATE THIS MORNING
MOVING NORTH-NORTHEAST INTO THE U.P. THIS EVENING. IN ADDITION TO
THE MID-LEVEL TROUGH A 120-130 KT JET STREAK DEVELOPS OVER THE
NORTHLAND LATE THIS MORNING RESULTING IN UPPER LEVEL DIVERGENCE
ACROSS NORTHERN WISCONSIN THIS AFTERNOON. FINALLY...WARM AIR
ADVECTION ONGOING AT LOW LEVELS HAS RAISED TEMPS TO THE MID 30S
ACROSS NORTHERN WISCONSIN WITH MODEL SOUNDINGS INDICATING A FAIRLY
WARM LAYER ALOFT...AS VERIFIED BY THE MPX 00Z SOUNDING. IN GENERAL
THE TREND IN GUIDANCE HAS BEEN A WESTWARD SHIFT AND STRONGER LARGE-
SCALE LIFT AS THE MID-LEVEL TROUGH RAPIDLY APPROACHES AND HEIGHTS
FALL THIS AFTERNOON. THE HRRR ACCENTUATES THIS TREND WITH RUNS THIS
MORNING COMING IN EVEN FURTHER WEST THAN MOST OF THE 00Z MODEL SUITE.
WHILE TEMPS ARE IN THE MID 30S ACROSS NORTHWEST WISCONSIN DEW POINTS
ARE STILL NEAR TO BELOW FREEZING...AND ONCE LOW LEVELS SATURATE
THINK THERE WILL BE A QUICK TRANSITION FROM LIGHT RAIN/DRIZZLE TO
SNOW ACROSS PARTS OF NORTHWEST WISCONSIN. THE RAIN/SNOW TRANSITION
LINE IS VERY CHALLENGING FOR TODAYS FORECAST WHICH RESULTS IN A
FAIRLY HIGH BUST POTENTIAL...BUT WITH THE LIKELIHOOD OF INTENSE
PRECIP AND TEMPS AT THE SFC AND THROUGH THE COLUMN COLD ENOUGH TO
SUPPORT SNOW BELIEVE THERE WILL BE A SWATH OF 2 TO 5 INCHES LATE
THIS MORNING INTO THE EARLY AFTERNOON. THUS...DECIDED TO GO WITH A
WINTER WX ADVISORY. THE RAIN/SNOW LINE LOOKS TO BE IN WESTERN
ASHLAND/SAWYER COUNTIES...AND DESPITE MOST OF THOSE COUNTIES
PROBABLY RECEIVING MAINLY RAIN TODAY THE FACT THAT /1/ THERE IS
STILL SOME UNCERTAINTY IN THIS FORECAST AND /2/ THE MOST POPULATED
CITIES IN EACH COUNTY ARE EXPECTED TO RECEIVE SNOW IS WHY WE DECIDED
TO ISSUE THE WINTER WX ADVISORY FOR THOSE COUNTIES. ON THE WEST
THERE WILL BE A SHARP CUT-OFF FOR WHERE THE ACCUMULATING SNOW
FALLS...WITH THIS LINE PROBABLY CLOSE TO THE TWIN PORTS. FOR NOW
HAVE 1 TO 3 INCHES OF SNOW FOR THE TWIN PORTS...THERE IS THE
POTENTIAL LITTLE IF ANY PRECIP OCCURS BUT DO NOT THINK THERE IS
POTENTIAL FOR MORE THAN THREE INCHES...SO DID NOT INCLUDE DULUTH IN
THE WINTER WX ADVISORY.
ELSEWHERE ACROSS NORTHEAST MINNESOTA...LIGHT SNOW WITH 1 TO 3 INCHES
IN THE ARROWHEAD..ELSEWHERE NOT MUCH DURING THE DAY BEFORE COLDER
AIR MOVES IN AND THE LOW MOVES NORTH INTO ONTARIO THIS EVENING
RESULTING IN LIGHT SNOW/FLURRIES LINGERING THROUGH EARLY THURSDAY.
EAST OF THE WINTER WX ADVISORY MAINLY RAIN TODAY WITH OVER A HALF
INCH LIKELY. RAIN CHANGES TO SNOW THIS EVENING FROM WEST TO
EAST...WITH A FEW INCHES OF SNOW POSSIBLE UNTIL THE SNOW ENDS
TOWARDS THURSDAY MORNING.
FINALLY...FOR THURSDAY AFTERNOON HIGH PRESSURE BUILDING IN ACROSS
THE MID MISSISSIPPI VALLEY COULD RESULT IN SOME PARTIAL CLEARING IN
CENTRAL MINNESOTA...BUT UNLIKELY GIVEN POTENT STRATUS DECK IN PLACE.
TEMPS FALL TO THE MID TEENS TO MID 20S TONIGHT AS PRECIP CHANGES
OVER TO SNOW...THEN ONLY CLIMBING AROUND 5 DEGREES TO THE 20S ON
THURSDAY AFTERNOON. WEST WINDS LATE TONIGHT INTO THURSDAY COULD BE
BREEZY FOR A TIME...THEN DIMINISH TOWARDS THURSDAY AFTERNOON.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 427 AM CST WED DEC 23 2015
THURSDAY NIGHT AND FRIDAY LOOK TO BE A QUIET LULL IN BETWEEN
SYSTEMS. THE MAIN QUESTION DURING THIS PERIOD WILL BE WHAT THE
CLOUD COVER DOES...AND ITS EFFECT ON TEMPERATURES. THE TREND THIS
TIME OF YEAR IS THAT UNLESS WE HAVE STRONG COLD DRY ADVECTION THAT
THOROUGHLY MIX OUT THE STRATUS...WE ARE LIKELY TO REMAIN STUCK IN
THE STRATUS IN BETWEEN THE SYSTEMS. SO...HAVE STAYED WITH A
CLOUDIER SOLUTION FOR NOW WITH NO GOOD STRONG PUSH TO GET RID OF THE
STRATUS AND HAVE STAYED WITH MODERATED TEMPERATURES THROUGHOUT.
HOWEVER...IF IT LOOKS LIKE WE MIGHT ACTUALLY CLEAR OUT AFTER
ALL...MY TEMPS ARE NOT COLD ENOUGH ALL AROUND. AS A FOOT
NOTE...HAVE NOTICED THE NAM RUNNING A WEAK FAST MOVING SHORTWAVE
ACROSS PARTS OF THE FORECAST AREA THURSDAY NIGHT...BUT IT IS THE
ONLY MODEL DOING THAT FOR NOW AND WHILE THE PREVIOUS RUNS HAVE
IT...THE TRACK HAS BEEN DRIFTING ABOUT AND REMAINS QUITE WEAK AND
MOSTLY SOUTH OF THE FORECAST AREA. SO...HAVE LEFT IT OUT FOR NOW.
THE NEXT SIGNIFICANT STORM MOVES THROUGH THE FORECAST AREA BEGINNING
FRIDAY NIGHT...AND CONTINUING SATURDAY BEFORE ENDING SATURDAY NIGHT
OR EARLY SUNDAY DEPENDING HOW MUCH LAKE EFFECT SNOW DEVELOPS. THE
MODELS ARE FAIRLY CONSISTENT IN BRINGING AN INVERTED SURFACE TROUGH
ACROSS THE FORECAST AREA DURING THE DAY ON SATURDAY...ASSOCIATED
WITH AN 850MB LOW THAT TRACKS FROM SE SD...EAST-NORTHEAST TO EASTERN
UPPER MICHIGAN DURING THE DAY ON SATURDAY. FOR NOW THIS KEEPS THE
FORECAST AREA IN BELOW ZERO TEMPERATURES ALOFT AND OUR PRECIPITATION
TYPE ALL SNOW...WITH NEAR TO A LITTLE HIGHER THAN NORMAL SNOW WATER
RATIOS FOR DECEMBER. MY INITIAL THOUGHTS BRING A SOLID 2 TO 4
INCHES ACROSS THE FORECAST AREA DURING THE EVENT...BUT WILL HAVE TO
WAIT AND SEE HOW THIS ONE DEVELOPS.
IT LOOKS LIKE ANOTHER STORM SYSTEM IS GOING TO MOVE ACROSS THE
MIDWEST ON MONDAY THROUGH TUESDAY...BRINGING ANOTHER CHANCE FOR
PRECIPITATION TO THE REGION. HOWEVER...THE LATEST MODELS ARE
KEEPING THIS SYSTEM MAINLY SOUTH OF THE FORECAST AREA AND HAVE PUT
IN LOWER POPS THAN WHAT WE PREVIOUSLY HAD TO TREND TOWARDS A DRIER
FORECAST. WILL HAVE TO SEE IF THIS TREND CONTINUES BEFORE REMOVING
THEM COMPLETELY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 535 AM CST WED DEC 23 2015
WIDESPREAD IFR CONDITIONS THIS MORNING TO CONTINUE THROUGH MUCH OF
THE NEXT 24 HOURS. A RAIN/SNOW MIXTURE TO SPREAD ACROSS THE
EASTERN TERMINALS...MAINLY KHYR...KDLH AND KHIB THROUGH
APPROXIMATELY 06Z TONIGHT BEFORE SLOWLY ENDING FROM WEST TO EAST.
SOME LOCATIONS TO EVEN DROP TO LIFR FOR A FEW HOURS THIS
AFTERNOON. IMPROVEMENT TO MVFR POSSIBLE FOR MN TERMINALS AFTER 09Z
TONIGHT.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 34 20 24 15 / 90 70 10 10
INL 34 21 23 11 / 20 50 30 10
BRD 33 18 24 15 / 20 20 10 0
HYR 36 23 28 15 / 100 80 20 10
ASX 36 27 29 20 / 100 90 20 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR
WIZ001>003-006>008.
MN...NONE.
LS...SMALL CRAFT ADVISORY UNTIL 10 AM CST THIS MORNING FOR LSZ140-141.
&&
$$
UPDATE...HUYCK
SHORT TERM...JJM
LONG TERM...LE
AVIATION...LE
AREA FORECAST DISCUSSION
NWS DULUTH MN
632 AM CST WED DEC 23 2015
.UPDATE...
ISSUED AT 630 AM CST WED DEC 23 2015
MINOR UPDATE TO POPS AND WEATHER...IN GENERAL FORECAST REMAINS ON
TRACK WITH A LIGHT WINTRY MIX QUICKING CHANGING TO MAINLY SNOW
WEST OF HIGHWAY 63 IN NW WISCONSIN AND MORE RAIN THAN SNOW EAST
OF HIGHWAY 63.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 427 AM CST WED DEC 23 2015
RAIN/SNOW WILL QUICKLY SPREAD ACROSS NORTHWEST WISCONSIN AND PARTS
OF NORTHEAST MINNESOTA TODAY RESULTING IN A QUICK FEW INCHES OF SNOW
FOR PARTS OF THE REGION. WHERE THE RAIN/SNOW LINE WILL BE IS STILL
DIFFICULT TO DETERMINE EVEN AT THIS SHORT TIME RANGE...BUT
CONFIDENCE HAS INCREASED IN COVERAGE OF PRECIPITATION /TRENDING
FARTHER WEST/ INTENSITY /HIGHER AMOUNTS/ AND RANGE OF PRECIP TYPES
EXPECTED /MAINLY JUST RAIN OR SNOW WITH LITTLE MIX/. RAIN/SNOW ENDS
QUICKLY FROM WEST TO EAST LATE TONIGHT WITH LINGERING FLURRIES
POSSIBLE INTO EARLY THURSDAY. WHEN IT IS ALL DONE THERE WILL LIKELY
BE A SWATH OF 2 TO 4 INCHES OF SNOW ACROSS A PORTION OF NORTHWEST
WISCONSIN...WITH OTHER LOCATIONS EXPERIENCE MAINLY RAIN ENDING AS
LIGHT SNOW.
ON THE SYNOPTIC SCALE A MID-LEVEL TROUGH AXIS WILL SWING NORTHEAST
FROM THE LOWER MISSOURI RIVER VALLEY INTO THE UPPER GREAT LAKES
TODAY. WHILE A POTENT LOW PRESSURE SYSTEM OVER THE RED RIVER VALLEY
MOVES NORTH INTO NORTHWEST ONTARIO IT WILL WEAKEN WHILE A STRONG AND
BROADER LOW PRESSURE DEVELOPS IN NORTHERN MISSOURI LATE THIS MORNING
MOVING NORTH-NORTHEAST INTO THE U.P. THIS EVENING. IN ADDITION TO
THE MID-LEVEL TROUGH A 120-130 KT JET STREAK DEVELOPS OVER THE
NORTHLAND LATE THIS MORNING RESULTING IN UPPER LEVEL DIVERGENCE
ACROSS NORTHERN WISCONSIN THIS AFTERNOON. FINALLY...WARM AIR
ADVECTION ONGOING AT LOW LEVELS HAS RAISED TEMPS TO THE MID 30S
ACROSS NORTHERN WISCONSIN WITH MODEL SOUNDINGS INDICATING A FAIRLY
WARM LAYER ALOFT...AS VERIFIED BY THE MPX 00Z SOUNDING. IN GENERAL
THE TREND IN GUIDANCE HAS BEEN A WESTWARD SHIFT AND STRONGER LARGE-
SCALE LIFT AS THE MID-LEVEL TROUGH RAPIDLY APPROACHES AND HEIGHTS
FALL THIS AFTERNOON. THE HRRR ACCENTUATES THIS TREND WITH RUNS THIS
MORNING COMING IN EVEN FURTHER WEST THAN MOST OF THE 00Z MODEL SUITE.
WHILE TEMPS ARE IN THE MID 30S ACROSS NORTHWEST WISCONSIN DEW POINTS
ARE STILL NEAR TO BELOW FREEZING...AND ONCE LOW LEVELS SATURATE
THINK THERE WILL BE A QUICK TRANSITION FROM LIGHT RAIN/DRIZZLE TO
SNOW ACROSS PARTS OF NORTHWEST WISCONSIN. THE RAIN/SNOW TRANSITION
LINE IS VERY CHALLENGING FOR TODAYS FORECAST WHICH RESULTS IN A
FAIRLY HIGH BUST POTENTIAL...BUT WITH THE LIKELIHOOD OF INTENSE
PRECIP AND TEMPS AT THE SFC AND THROUGH THE COLUMN COLD ENOUGH TO
SUPPORT SNOW BELIEVE THERE WILL BE A SWATH OF 2 TO 5 INCHES LATE
THIS MORNING INTO THE EARLY AFTERNOON. THUS...DECIDED TO GO WITH A
WINTER WX ADVISORY. THE RAIN/SNOW LINE LOOKS TO BE IN WESTERN
ASHLAND/SAWYER COUNTIES...AND DESPITE MOST OF THOSE COUNTIES
PROBABLY RECEIVING MAINLY RAIN TODAY THE FACT THAT /1/ THERE IS
STILL SOME UNCERTAINTY IN THIS FORECAST AND /2/ THE MOST POPULATED
CITIES IN EACH COUNTY ARE EXPECTED TO RECEIVE SNOW IS WHY WE DECIDED
TO ISSUE THE WINTER WX ADVISORY FOR THOSE COUNTIES. ON THE WEST
THERE WILL BE A SHARP CUT-OFF FOR WHERE THE ACCUMULATING SNOW
FALLS...WITH THIS LINE PROBABLY CLOSE TO THE TWIN PORTS. FOR NOW
HAVE 1 TO 3 INCHES OF SNOW FOR THE TWIN PORTS...THERE IS THE
POTENTIAL LITTLE IF ANY PRECIP OCCURS BUT DO NOT THINK THERE IS
POTENTIAL FOR MORE THAN THREE INCHES...SO DID NOT INCLUDE DULUTH IN
THE WINTER WX ADVISORY.
ELSEWHERE ACROSS NORTHEAST MINNESOTA...LIGHT SNOW WITH 1 TO 3 INCHES
IN THE ARROWHEAD..ELSEWHERE NOT MUCH DURING THE DAY BEFORE COLDER
AIR MOVES IN AND THE LOW MOVES NORTH INTO ONTARIO THIS EVENING
RESULTING IN LIGHT SNOW/FLURRIES LINGERING THROUGH EARLY THURSDAY.
EAST OF THE WINTER WX ADVISORY MAINLY RAIN TODAY WITH OVER A HALF
INCH LIKELY. RAIN CHANGES TO SNOW THIS EVENING FROM WEST TO
EAST...WITH A FEW INCHES OF SNOW POSSIBLE UNTIL THE SNOW ENDS
TOWARDS THURSDAY MORNING.
FINALLY...FOR THURSDAY AFTERNOON HIGH PRESSURE BUILDING IN ACROSS
THE MID MISSISSIPPI VALLEY COULD RESULT IN SOME PARTIAL CLEARING IN
CENTRAL MINNESOTA...BUT UNLIKELY GIVEN POTENT STRATUS DECK IN PLACE.
TEMPS FALL TO THE MID TEENS TO MID 20S TONIGHT AS PRECIP CHANGES
OVER TO SNOW...THEN ONLY CLIMBING AROUND 5 DEGREES TO THE 20S ON
THURSDAY AFTERNOON. WEST WINDS LATE TONIGHT INTO THURSDAY COULD BE
BREEZY FOR A TIME...THEN DIMINISH TOWARDS THURSDAY AFTERNOON.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 427 AM CST WED DEC 23 2015
THURSDAY NIGHT AND FRIDAY LOOK TO BE A QUIET LULL IN BETWEEN
SYSTEMS. THE MAIN QUESTION DURING THIS PERIOD WILL BE WHAT THE
CLOUD COVER DOES...AND ITS EFFECT ON TEMPERATURES. THE TREND THIS
TIME OF YEAR IS THAT UNLESS WE HAVE STRONG COLD DRY ADVECTION THAT
THOROUGHLY MIX OUT THE STRATUS...WE ARE LIKELY TO REMAIN STUCK IN
THE STRATUS IN BETWEEN THE SYSTEMS. SO...HAVE STAYED WITH A
CLOUDIER SOLUTION FOR NOW WITH NO GOOD STRONG PUSH TO GET RID OF THE
STRATUS AND HAVE STAYED WITH MODERATED TEMPERATURES THROUGHOUT.
HOWEVER...IF IT LOOKS LIKE WE MIGHT ACTUALLY CLEAR OUT AFTER
ALL...MY TEMPS ARE NOT COLD ENOUGH ALL AROUND. AS A FOOT
NOTE...HAVE NOTICED THE NAM RUNNING A WEAK FAST MOVING SHORTWAVE
ACROSS PARTS OF THE FORECAST AREA THURSDAY NIGHT...BUT IT IS THE
ONLY MODEL DOING THAT FOR NOW AND WHILE THE PREVIOUS RUNS HAVE
IT...THE TRACK HAS BEEN DRIFTING ABOUT AND REMAINS QUITE WEAK AND
MOSTLY SOUTH OF THE FORECAST AREA. SO...HAVE LEFT IT OUT FOR NOW.
THE NEXT SIGNIFICANT STORM MOVES THROUGH THE FORECAST AREA BEGINNING
FRIDAY NIGHT...AND CONTINUING SATURDAY BEFORE ENDING SATURDAY NIGHT
OR EARLY SUNDAY DEPENDING HOW MUCH LAKE EFFECT SNOW DEVELOPS. THE
MODELS ARE FAIRLY CONSISTENT IN BRINGING AN INVERTED SURFACE TROUGH
ACROSS THE FORECAST AREA DURING THE DAY ON SATURDAY...ASSOCIATED
WITH AN 850MB LOW THAT TRACKS FROM SE SD...EAST-NORTHEAST TO EASTERN
UPPER MICHIGAN DURING THE DAY ON SATURDAY. FOR NOW THIS KEEPS THE
FORECAST AREA IN BELOW ZERO TEMPERATURES ALOFT AND OUR PRECIPITATION
TYPE ALL SNOW...WITH NEAR TO A LITTLE HIGHER THAN NORMAL SNOW WATER
RATIOS FOR DECEMBER. MY INITIAL THOUGHTS BRING A SOLID 2 TO 4
INCHES ACROSS THE FORECAST AREA DURING THE EVENT...BUT WILL HAVE TO
WAIT AND SEE HOW THIS ONE DEVELOPS.
IT LOOKS LIKE ANOTHER STORM SYSTEM IS GOING TO MOVE ACROSS THE
MIDWEST ON MONDAY THROUGH TUESDAY...BRINGING ANOTHER CHANCE FOR
PRECIPITATION TO THE REGION. HOWEVER...THE LATEST MODELS ARE
KEEPING THIS SYSTEM MAINLY SOUTH OF THE FORECAST AREA AND HAVE PUT
IN LOWER POPS THAN WHAT WE PREVIOUSLY HAD TO TREND TOWARDS A DRIER
FORECAST. WILL HAVE TO SEE IF THIS TREND CONTINUES BEFORE REMOVING
THEM COMPLETELY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 535 AM CST WED DEC 23 2015
WIDESPREAD IFR CONDITIONS THIS MORNING TO CONTINUE THROUGH MUCH OF
THE NEXT 24 HOURS. A RAIN/SNOW MIXTURE TO SPREAD ACROSS THE
EASTERN TERMINALS...MAINLY KHYR...KDLH AND KHIB THROUGH
APPROXIMATELY 06Z TONIGHT BEFORE SLOWLY ENDING FROM WEST TO EAST.
SOME LOCATIONS TO EVEN DROP TO LIFR FOR A FEW HOURS THIS
AFTERNOON. IMPROVEMENT TO MVFR POSSIBLE FOR MN TERMINALS AFTER 09Z
TONIGHT.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 34 20 24 15 / 80 60 10 10
INL 33 21 23 11 / 20 50 30 10
BRD 33 18 24 15 / 20 20 10 0
HYR 36 23 28 15 / 100 80 20 10
ASX 36 27 29 20 / 100 70 20 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR
WIZ001>003-006>008.
MN...NONE.
LS...SMALL CRAFT ADVISORY UNTIL 10 AM CST THIS MORNING FOR LSZ140-141.
&&
$$
UPDATE...JJM
SHORT TERM...JJM
LONG TERM...LE
AVIATION...LE
AREA FORECAST DISCUSSION
NWS DULUTH MN
540 AM CST WED DEC 23 2015
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 427 AM CST WED DEC 23 2015
RAIN/SNOW WILL QUICKLY SPREAD ACROSS NORTHWEST WISCONSIN AND PARTS
OF NORTHEAST MINNESOTA TODAY RESULTING IN A QUICK FEW INCHES OF SNOW
FOR PARTS OF THE REGION. WHERE THE RAIN/SNOW LINE WILL BE IS STILL
DIFFICULT TO DETERMINE EVEN AT THIS SHORT TIME RANGE...BUT
CONFIDENCE HAS INCREASED IN COVERAGE OF PRECIPITATION /TRENDING
FARTHER WEST/ INTENSITY /HIGHER AMOUNTS/ AND RANGE OF PRECIP TYPES
EXPECTED /MAINLY JUST RAIN OR SNOW WITH LITTLE MIX/. RAIN/SNOW ENDS
QUICKLY FROM WEST TO EAST LATE TONIGHT WITH LINGERING FLURRIES
POSSIBLE INTO EARLY THURSDAY. WHEN IT IS ALL DONE THERE WILL LIKELY
BE A SWATH OF 2 TO 4 INCHES OF SNOW ACROSS A PORTION OF NORTHWEST
WISCONSIN...WITH OTHER LOCATIONS EXPERIENCE MAINLY RAIN ENDING AS
LIGHT SNOW.
ON THE SYNOPTIC SCALE A MID-LEVEL TROUGH AXIS WILL SWING NORTHEAST
FROM THE LOWER MISSOURI RIVER VALLEY INTO THE UPPER GREAT LAKES
TODAY. WHILE A POTENT LOW PRESSURE SYSTEM OVER THE RED RIVER VALLEY
MOVES NORTH INTO NORTHWEST ONTARIO IT WILL WEAKEN WHILE A STRONG AND
BROADER LOW PRESSURE DEVELOPS IN NORTHERN MISSOURI LATE THIS MORNING
MOVING NORTH-NORTHEAST INTO THE U.P. THIS EVENING. IN ADDITION TO
THE MID-LEVEL TROUGH A 120-130 KT JET STREAK DEVELOPS OVER THE
NORTHLAND LATE THIS MORNING RESULTING IN UPPER LEVEL DIVERGENCE
ACROSS NORTHERN WISCONSIN THIS AFTERNOON. FINALLY...WARM AIR
ADVECTION ONGOING AT LOW LEVELS HAS RAISED TEMPS TO THE MID 30S
ACROSS NORTHERN WISCONSIN WITH MODEL SOUNDINGS INDICATING A FAIRLY
WARM LAYER ALOFT...AS VERIFIED BY THE MPX 00Z SOUNDING. IN GENERAL
THE TREND IN GUIDANCE HAS BEEN A WESTWARD SHIFT AND STRONGER LARGE-
SCALE LIFT AS THE MID-LEVEL TROUGH RAPIDLY APPROACHES AND HEIGHTS
FALL THIS AFTERNOON. THE HRRR ACCENTUATES THIS TREND WITH RUNS THIS
MORNING COMING IN EVEN FURTHER WEST THAN MOST OF THE 00Z MODEL SUITE.
WHILE TEMPS ARE IN THE MID 30S ACROSS NORTHWEST WISCONSIN DEW POINTS
ARE STILL NEAR TO BELOW FREEZING...AND ONCE LOW LEVELS SATURATE
THINK THERE WILL BE A QUICK TRANSITION FROM LIGHT RAIN/DRIZZLE TO
SNOW ACROSS PARTS OF NORTHWEST WISCONSIN. THE RAIN/SNOW TRANSITION
LINE IS VERY CHALLENGING FOR TODAYS FORECAST WHICH RESULTS IN A
FAIRLY HIGH BUST POTENTIAL...BUT WITH THE LIKELIHOOD OF INTENSE
PRECIP AND TEMPS AT THE SFC AND THROUGH THE COLUMN COLD ENOUGH TO
SUPPORT SNOW BELIEVE THERE WILL BE A SWATH OF 2 TO 5 INCHES LATE
THIS MORNING INTO THE EARLY AFTERNOON. THUS...DECIDED TO GO WITH A
WINTER WX ADVISORY. THE RAIN/SNOW LINE LOOKS TO BE IN WESTERN
ASHLAND/SAWYER COUNTIES...AND DESPITE MOST OF THOSE COUNTIES
PROBABLY RECEIVING MAINLY RAIN TODAY THE FACT THAT /1/ THERE IS
STILL SOME UNCERTAINTY IN THIS FORECAST AND /2/ THE MOST POPULATED
CITIES IN EACH COUNTY ARE EXPECTED TO RECEIVE SNOW IS WHY WE DECIDED
TO ISSUE THE WINTER WX ADVISORY FOR THOSE COUNTIES. ON THE WEST
THERE WILL BE A SHARP CUT-OFF FOR WHERE THE ACCUMULATING SNOW
FALLS...WITH THIS LINE PROBABLY CLOSE TO THE TWIN PORTS. FOR NOW
HAVE 1 TO 3 INCHES OF SNOW FOR THE TWIN PORTS...THERE IS THE
POTENTIAL LITTLE IF ANY PRECIP OCCURS BUT DO NOT THINK THERE IS
POTENTIAL FOR MORE THAN THREE INCHES...SO DID NOT INCLUDE DULUTH IN
THE WINTER WX ADVISORY.
ELSEWHERE ACROSS NORTHEAST MINNESOTA...LIGHT SNOW WITH 1 TO 3 INCHES
IN THE ARROWHEAD..ELSEWHERE NOT MUCH DURING THE DAY BEFORE COLDER
AIR MOVES IN AND THE LOW MOVES NORTH INTO ONTARIO THIS EVENING
RESULTING IN LIGHT SNOW/FLURRIES LINGERING THROUGH EARLY THURSDAY.
EAST OF THE WINTER WX ADVISORY MAINLY RAIN TODAY WITH OVER A HALF
INCH LIKELY. RAIN CHANGES TO SNOW THIS EVENING FROM WEST TO
EAST...WITH A FEW INCHES OF SNOW POSSIBLE UNTIL THE SNOW ENDS
TOWARDS THURSDAY MORNING.
FINALLY...FOR THURSDAY AFTERNOON HIGH PRESSURE BUILDING IN ACROSS
THE MID MISSISSIPPI VALLEY COULD RESULT IN SOME PARTIAL CLEARING IN
CENTRAL MINNESOTA...BUT UNLIKELY GIVEN POTENT STRATUS DECK IN PLACE.
TEMPS FALL TO THE MID TEENS TO MID 20S TONIGHT AS PRECIP CHANGES
OVER TO SNOW...THEN ONLY CLIMBING AROUND 5 DEGREES TO THE 20S ON
THURSDAY AFTERNOON. WEST WINDS LATE TONIGHT INTO THURSDAY COULD BE
BREEZY FOR A TIME...THEN DIMINISH TOWARDS THURSDAY AFTERNOON.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 427 AM CST WED DEC 23 2015
THURSDAY NIGHT AND FRIDAY LOOK TO BE A QUIET LULL IN BETWEEN
SYSTEMS. THE MAIN QUESTION DURING THIS PERIOD WILL BE WHAT THE
CLOUD COVER DOES...AND ITS EFFECT ON TEMPERATURES. THE TREND THIS
TIME OF YEAR IS THAT UNLESS WE HAVE STRONG COLD DRY ADVECTION THAT
THOROUGHLY MIX OUT THE STRATUS...WE ARE LIKELY TO REMAIN STUCK IN
THE STRATUS IN BETWEEN THE SYSTEMS. SO...HAVE STAYED WITH A
CLOUDIER SOLUTION FOR NOW WITH NO GOOD STRONG PUSH TO GET RID OF THE
STRATUS AND HAVE STAYED WITH MODERATED TEMPERATURES THROUGHOUT.
HOWEVER...IF IT LOOKS LIKE WE MIGHT ACTUALLY CLEAR OUT AFTER
ALL...MY TEMPS ARE NOT COLD ENOUGH ALL AROUND. AS A FOOT
NOTE...HAVE NOTICED THE NAM RUNNING A WEAK FAST MOVING SHORTWAVE
ACROSS PARTS OF THE FORECAST AREA THURSDAY NIGHT...BUT IT IS THE
ONLY MODEL DOING THAT FOR NOW AND WHILE THE PREVIOUS RUNS HAVE
IT...THE TRACK HAS BEEN DRIFTING ABOUT AND REMAINS QUITE WEAK AND
MOSTLY SOUTH OF THE FORECAST AREA. SO...HAVE LEFT IT OUT FOR NOW.
THE NEXT SIGNIFICANT STORM MOVES THROUGH THE FORECAST AREA BEGINNING
FRIDAY NIGHT...AND CONTINUING SATURDAY BEFORE ENDING SATURDAY NIGHT
OR EARLY SUNDAY DEPENDING HOW MUCH LAKE EFFECT SNOW DEVELOPS. THE
MODELS ARE FAIRLY CONSISTENT IN BRINGING AN INVERTED SURFACE TROUGH
ACROSS THE FORECAST AREA DURING THE DAY ON SATURDAY...ASSOCIATED
WITH AN 850MB LOW THAT TRACKS FROM SE SD...EAST-NORTHEAST TO EASTERN
UPPER MICHIGAN DURING THE DAY ON SATURDAY. FOR NOW THIS KEEPS THE
FORECAST AREA IN BELOW ZERO TEMPERATURES ALOFT AND OUR PRECIPITATION
TYPE ALL SNOW...WITH NEAR TO A LITTLE HIGHER THAN NORMAL SNOW WATER
RATIOS FOR DECEMBER. MY INITIAL THOUGHTS BRING A SOLID 2 TO 4
INCHES ACROSS THE FORECAST AREA DURING THE EVENT...BUT WILL HAVE TO
WAIT AND SEE HOW THIS ONE DEVELOPS.
IT LOOKS LIKE ANOTHER STORM SYSTEM IS GOING TO MOVE ACROSS THE
MIDWEST ON MONDAY THROUGH TUESDAY...BRINGING ANOTHER CHANCE FOR
PRECIPITATION TO THE REGION. HOWEVER...THE LATEST MODELS ARE
KEEPING THIS SYSTEM MAINLY SOUTH OF THE FORECAST AREA AND HAVE PUT
IN LOWER POPS THAN WHAT WE PREVIOUSLY HAD TO TREND TOWARDS A DRIER
FORECAST. WILL HAVE TO SEE IF THIS TREND CONTINUES BEFORE REMOVING
THEM COMPLETELY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 535 AM CST WED DEC 23 2015
WIDESPREAD IFR CONDITIONS THIS MORNING TO CONTINUE THROUGH MUCH OF
THE NEXT 24 HOURS. A RAIN/SNOW MIXTURE TO SPREAD ACROSS THE
EASTERN TERMINALS...MAINLY KHYR...KDLH AND KHIB THROUGH
APPROXIMATELY 06Z TONIGHT BEFORE SLOWLY ENDING FROM WEST TO EAST.
SOME LOCATIONS TO EVEN DROP TO LIFR FOR A FEW HOURS THIS
AFTERNOON. IMPROVEMENT TO MVFR POSSIBLE FOR MN TERMINALS AFTER 09Z
TONIGHT.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 34 20 24 15 / 80 60 10 10
INL 33 21 23 11 / 20 50 30 10
BRD 33 18 24 15 / 20 20 10 0
HYR 36 23 28 15 / 100 80 20 10
ASX 36 27 29 20 / 100 70 20 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...WINTER WEATHER ADVISORY FROM 9 AM THIS MORNING TO MIDNIGHT CST
TONIGHT FOR WIZ001>003-006>008.
MN...NONE.
LS...SMALL CRAFT ADVISORY UNTIL 10 AM CST THIS MORNING FOR LSZ140-141.
&&
$$
SHORT TERM...JJM
LONG TERM...LE
AVIATION...LE
AREA FORECAST DISCUSSION
NWS DULUTH MN
428 AM CST WED DEC 23 2015
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 427 AM CST WED DEC 23 2015
RAIN/SNOW WILL QUICKLY SPREAD ACROSS NORTHWEST WISCONSIN AND PARTS
OF NORTHEAST MINNESOTA TODAY RESULTING IN A QUICK FEW INCHES OF SNOW
FOR PARTS OF THE REGION. WHERE THE RAIN/SNOW LINE WILL BE IS STILL
DIFFICULT TO DETERMINE EVEN AT THIS SHORT TIME RANGE...BUT
CONFIDENCE HAS INCREASED IN COVERAGE OF PRECIPITATION /TRENDING
FARTHER WEST/ INTENSITY /HIGHER AMOUNTS/ AND RANGE OF PRECIP TYPES
EXPECTED /MAINLY JUST RAIN OR SNOW WITH LITTLE MIX/. RAIN/SNOW ENDS
QUICKLY FROM WEST TO EAST LATE TONIGHT WITH LINGERING FLURRIES
POSSIBLE INTO EARLY THURSDAY. WHEN IT IS ALL DONE THERE WILL LIKELY
BE A SWATH OF 2 TO 4 INCHES OF SNOW ACROSS A PORTION OF NORTHWEST
WISCONSIN...WITH OTHER LOCATIONS EXPERIENCE MAINLY RAIN ENDING AS
LIGHT SNOW.
ON THE SYNOPTIC SCALE A MID-LEVEL TROUGH AXIS WILL SWING NORTHEAST
FROM THE LOWER MISSOURI RIVER VALLEY INTO THE UPPER GREAT LAKES
TODAY. WHILE A POTENT LOW PRESSURE SYSTEM OVER THE RED RIVER VALLEY
MOVES NORTH INTO NORTHWEST ONTARIO IT WILL WEAKEN WHILE A STRONG AND
BROADER LOW PRESSURE DEVELOPS IN NORTHERN MISSOURI LATE THIS MORNING
MOVING NORTH-NORTHEAST INTO THE U.P. THIS EVENING. IN ADDITION TO
THE MID-LEVEL TROUGH A 120-130 KT JET STREAK DEVELOPS OVER THE
NORTHLAND LATE THIS MORNING RESULTING IN UPPER LEVEL DIVERGENCE
ACROSS NORTHERN WISCONSIN THIS AFTERNOON. FINALLY...WARM AIR
ADVECTION ONGOING AT LOW LEVELS HAS RAISED TEMPS TO THE MID 30S
ACROSS NORTHERN WISCONSIN WITH MODEL SOUNDINGS INDICATING A FAIRLY
WARM LAYER ALOFT...AS VERIFIED BY THE MPX 00Z SOUNDING. IN GENERAL
THE TREND IN GUIDANCE HAS BEEN A WESTWARD SHIFT AND STRONGER LARGE-
SCALE LIFT AS THE MID-LEVEL TROUGH RAPIDLY APPROACHES AND HEIGHTS
FALL THIS AFTERNOON. THE HRRR ACCENTUATES THIS TREND WITH RUNS THIS
MORNING COMING IN EVEN FURTHER WEST THAN MOST OF THE 00Z MODEL SUITE.
WHILE TEMPS ARE IN THE MID 30S ACROSS NORTHWEST WISCONSIN DEW POINTS
ARE STILL NEAR TO BELOW FREEZING...AND ONCE LOW LEVELS SATURATE
THINK THERE WILL BE A QUICK TRANSITION FROM LIGHT RAIN/DRIZZLE TO
SNOW ACROSS PARTS OF NORTHWEST WISCONSIN. THE RAIN/SNOW TRANSITION
LINE IS VERY CHALLENGING FOR TODAYS FORECAST WHICH RESULTS IN A
FAIRLY HIGH BUST POTENTIAL...BUT WITH THE LIKELIHOOD OF INTENSE
PRECIP AND TEMPS AT THE SFC AND THROUGH THE COLUMN COLD ENOUGH TO
SUPPORT SNOW BELIEVE THERE WILL BE A SWATH OF 2 TO 5 INCHES LATE
THIS MORNING INTO THE EARLY AFTERNOON. THUS...DECIDED TO GO WITH A
WINTER WX ADVISORY. THE RAIN/SNOW LINE LOOKS TO BE IN WESTERN
ASHLAND/SAWYER COUNTIES...AND DESPITE MOST OF THOSE COUNTIES
PROBABLY RECEIVING MAINLY RAIN TODAY THE FACT THAT /1/ THERE IS
STILL SOME UNCERTAINTY IN THIS FORECAST AND /2/ THE MOST POPULATED
CITIES IN EACH COUNTY ARE EXPECTED TO RECEIVE SNOW IS WHY WE DECIDED
TO ISSUE THE WINTER WX ADVISORY FOR THOSE COUNTIES. ON THE WEST
THERE WILL BE A SHARP CUT-OFF FOR WHERE THE ACCUMULATING SNOW
FALLS...WITH THIS LINE PROBABLY CLOSE TO THE TWIN PORTS. FOR NOW
HAVE 1 TO 3 INCHES OF SNOW FOR THE TWIN PORTS...THERE IS THE
POTENTIAL LITTLE IF ANY PRECIP OCCURS BUT DO NOT THINK THERE IS
POTENTIAL FOR MORE THAN THREE INCHES...SO DID NOT INCLUDE DULUTH IN
THE WINTER WX ADVISORY.
ELSEWHERE ACROSS NORTHEAST MINNESOTA...LIGHT SNOW WITH 1 TO 3 INCHES
IN THE ARROWHEAD..ELSEWHERE NOT MUCH DURING THE DAY BEFORE COLDER
AIR MOVES IN AND THE LOW MOVES NORTH INTO ONTARIO THIS EVENING
RESULTING IN LIGHT SNOW/FLURRIES LINGERING THROUGH EARLY THURSDAY.
EAST OF THE WINTER WX ADVISORY MAINLY RAIN TODAY WITH OVER A HALF
INCH LIKELY. RAIN CHANGES TO SNOW THIS EVENING FROM WEST TO
EAST...WITH A FEW INCHES OF SNOW POSSIBLE UNTIL THE SNOW ENDS
TOWARDS THURSDAY MORNING.
FINALLY...FOR THURSDAY AFTERNOON HIGH PRESSURE BUILDING IN ACROSS
THE MID MISSISSIPPI VALLEY COULD RESULT IN SOME PARTIAL CLEARING IN
CENTRAL MINNESOTA...BUT UNLIKELY GIVEN POTENT STRATUS DECK IN PLACE.
TEMPS FALL TO THE MID TEENS TO MID 20S TONIGHT AS PRECIP CHANGES
OVER TO SNOW...THEN ONLY CLIMBING AROUND 5 DEGREES TO THE 20S ON
THURSDAY AFTERNOON. WEST WINDS LATE TONIGHT INTO THURSDAY COULD BE
BREEZY FOR A TIME...THEN DIMINISH TOWARDS THURSDAY AFTERNOON.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 427 AM CST WED DEC 23 2015
THURSDAY NIGHT AND FRIDAY LOOK TO BE A QUIET LULL IN BETWEEN
SYSTEMS. THE MAIN QUESTION DURING THIS PERIOD WILL BE WHAT THE
CLOUD COVER DOES...AND ITS EFFECT ON TEMPERATURES. THE TREND THIS
TIME OF YEAR IS THAT UNLESS WE HAVE STRONG COLD DRY ADVECTION THAT
THOROUGHLY MIX OUT THE STRATUS...WE ARE LIKELY TO REMAIN STUCK IN
THE STRATUS IN BETWEEN THE SYSTEMS. SO...HAVE STAYED WITH A
CLOUDIER SOLUTION FOR NOW WITH NO GOOD STRONG PUSH TO GET RID OF THE
STRATUS AND HAVE STAYED WITH MODERATED TEMPERATURES THROUGHOUT.
HOWEVER...IF IT LOOKS LIKE WE MIGHT ACTUALLY CLEAR OUT AFTER
ALL...MY TEMPS ARE NOT COLD ENOUGH ALL AROUND. AS A FOOT
NOTE...HAVE NOTICED THE NAM RUNNING A WEAK FAST MOVING SHORTWAVE
ACROSS PARTS OF THE FORECAST AREA THURSDAY NIGHT...BUT IT IS THE
ONLY MODEL DOING THAT FOR NOW AND WHILE THE PREVIOUS RUNS HAVE
IT...THE TRACK HAS BEEN DRIFTING ABOUT AND REMAINS QUITE WEAK AND
MOSTLY SOUTH OF THE FORECAST AREA. SO...HAVE LEFT IT OUT FOR NOW.
THE NEXT SIGNIFICANT STORM MOVES THROUGH THE FORECAST AREA BEGINNING
FRIDAY NIGHT...AND CONTINUING SATURDAY BEFORE ENDING SATURDAY NIGHT
OR EARLY SUNDAY DEPENDING HOW MUCH LAKE EFFECT SNOW DEVELOPS. THE
MODELS ARE FAIRLY CONSISTENT IN BRINGING AN INVERTED SURFACE TROUGH
ACROSS THE FORECAST AREA DURING THE DAY ON SATURDAY...ASSOCIATED
WITH AN 850MB LOW THAT TRACKS FROM SE SD...EAST-NORTHEAST TO EASTERN
UPPER MICHIGAN DURING THE DAY ON SATURDAY. FOR NOW THIS KEEPS THE
FORECAST AREA IN BELOW ZERO TEMPERATURES ALOFT AND OUR PRECIPITATION
TYPE ALL SNOW...WITH NEAR TO A LITTLE HIGHER THAN NORMAL SNOW WATER
RATIOS FOR DECEMBER. MY INITIAL THOUGHTS BRING A SOLID 2 TO 4
INCHES ACROSS THE FORECAST AREA DURING THE EVENT...BUT WILL HAVE TO
WAIT AND SEE HOW THIS ONE DEVELOPS.
IT LOOKS LIKE ANOTHER STORM SYSTEM IS GOING TO MOVE ACROSS THE
MIDWEST ON MONDAY THROUGH TUESDAY...BRINGING ANOTHER CHANCE FOR
PRECIPITATION TO THE REGION. HOWEVER...THE LATEST MODELS ARE
KEEPING THIS SYSTEM MAINLY SOUTH OF THE FORECAST AREA AND HAVE PUT
IN LOWER POPS THAN WHAT WE PREVIOUSLY HAD TO TREND TOWARDS A DRIER
FORECAST. WILL HAVE TO SEE IF THIS TREND CONTINUES BEFORE REMOVING
THEM COMPLETELY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1144 PM CST TUE DEC 22 2015
A MIX OF MVFR/VFR AT THE BEGINNING OF THE FORECAST AS DRIER AIR
HAS ERODED SOME OF THE LOWER CIGS. NEXT ROUND OF PCPN WILL AFFECT
PRIMARILY DLH AND HYR ABOUT 15Z. WITH THE WARM TEMPS IN
PLACE...EXPECT LIGHT RAIN. THIS WILL CONTINUE UNTIL 00Z WHEN
COLDER AIR BEGINS TO CHANGE THE RAIN OVER TO SNOW. CIGS WILL DROP
BACK INTO THE IFR/LOW END MVFR RANGE WITH THE PCPN.
ELSEWHERE...THE MVFR CIGS PREVAIL WITH SOME FLURRIES AFTER 21Z.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 34 20 24 15 / 80 60 10 10
INL 33 21 23 11 / 20 50 30 10
BRD 33 18 24 15 / 20 20 10 0
HYR 36 23 28 15 / 100 80 20 10
ASX 36 27 29 20 / 100 70 20 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...WINTER WEATHER ADVISORY FROM 9 AM THIS MORNING TO MIDNIGHT CST
TONIGHT FOR WIZ001>003-006>008.
MN...NONE.
LS...SMALL CRAFT ADVISORY UNTIL 10 AM CST THIS MORNING FOR LSZ140-141.
&&
$$
SHORT TERM...JJM
LONG TERM...LE
AVIATION...GSF
AREA FORECAST DISCUSSION
NWS HASTINGS NE
516 AM CST WED DEC 23 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 332 AM CST WED DEC 23 2015
RADAR HAS AREAS OF LIGHT RAIN MOVING THROUGH THE EASTERN PART OF THE
FORECAST AREA EARLY THIS MORNING. TEMPERATURES IN THE AREA OF RAIN
ARE WARM ENOUGH AT THIS TIME TO CONTINUE TO BE RAIN. TO THE WEST OF
THE RAIN THE TEMPERATURES HAVE STARTED TO COOL OFF.
THROUGH DAYBREAK AND INTO THE MORNING HOURS AN UPPER LEVEL LOW IS
MOVING THROUGH THE AREA. EVEN THOUGH IT IS IN THE FIRST FEW HOURS OF
THE FORECAST...THERE ARE A FEW DIFFERENCES. THE HRRR AND RAP KEEP
PRECIPITATION ONLY IN THE FAR EAST WHILE THE 4KM WRF...NAM AND GFS
PUSH THE PRECIPITATION FURTHER TO THE EAST. THE BEST CHANCE WILL
DEFINITELY BE IN THE EAST...BUT HAVE KEPT SOME LOWER POPS FURTHER TO
THE WEST. THIS BRINGS IN A PROBLEM FOR PRECIPITATION TYPE. WHILE THE
TEMPERATURES ALOFT ARE WARM ENOUGH FOR RAIN...SO IS THE SURFACE.
ONCE THE TEMPERATURES ALOFT COOL OFF THE SURFACE DOES AS
WELL...MAKING A CHANGE TO SNOW. HAVE KEPT A RAIN AND SNOW MIX IN THE
WEST/NORTHWEST THROUGH DAY BREAK AND INTO THE MORNING HOURS AS THE
PRECIPITATION IS MOVING OUT OF THE AREA. BY MID DAY THE UPPER LOW
HAS MOVED EAST AND EXPECT THAT PRECIPITATION SHOULD COME TO AN END.
THERE WILL ALSO BE SOME CLEARING AND A LITTLE SUNSHINE FOR A TIME
THIS AFTERNOON.
THE NEXT UPPER LEVEL WAVE WILL BE MOVING INTO THE AREA TONIGHT.
EXPECT PRECIPITATION TO MOVE INTO THE AREA FROM THE SOUTHWEST
TONIGHT. TEMPERATURES ARE EXPECTED TO BE COLD ENOUGH THAT EXPECT
SNOW ACROSS THE ENTIRE AREA. THE BEST CHANCE FOR ACCUMULATING SNOW
WILL BE MAINLY LATE TONIGHT. THROUGH MORNING...EXPECT THERE TO BE
LESS THAN AN INCH OR LESS OF SNOW.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 347 AM CST WED DEC 23 2015
THE MID AND LONG TERM FORECASTS CONTINUE TO BE INTERESTING AND
CHALLENGING.
CHRISTMAS EVE - CHRISTMAS NIGHT:
THERE MAY BE SOME LINGERING SNOW ACROSS THE AREA EARLY THURSDAY
MORNING...BUT EXPECT IT TO MOVE OFF OVER EASTERN NEBRASKA BY MID
MORNING. SKIES ARE EXPECTED TO CLEAR AND HIGHS...IF NOT IMPACTED
MUCH BY ANY SNOW ACCUMULATION OVERNIGHT WILL REACH INTO THE 30S TO
LOW 40S.
ON CHRISTMAS DAY A PIECE OF THE MAIN DISTURBANCE THAT WILL IMPACT
THE REGION FOR THE WEEKEND INTO EARLY NEXT WEEK WILL BREAK OFF AND
MOVE NORTHEAST ACROSS THE AREA. THIS WILL BRING THE POSSIBILITY
FOR PRECIPITATION MAINLY ACROSS NORTHERN NEBRASKA...BUT SOME COULD
CREEP INTO CENTRAL NEBRASKA DURING THE LATE AFTERNOON AND
OVERNIGHT. HIGHS WILL BE SIMILAR TO THURSDAY.
SATURDAY - TUESDAY:
THIS PERIOD IS THE MOST CHALLENGING. THE GUIDANCE HAS EVOLVED FROM
LAST NIGHT`S...GIVING A SLOWER SOLUTION...TRENDING TOWARDS LAST
NIGHTS ECMWF. THE SLOWER/FURTHER SOUTH ROUTE IS IMPACTING THE
AREA OF PRECIPITATION POTENTIAL. CONFIDENCE ON THIS PART OF THE
FORECAST IS RELATIVELY LOW. CONFIDENCE IS HIGH THAT A SYSTEM WILL
IMPACT THE CENTRAL AND SOUTHERN PLAINS...BUT THE DETAILS OF WHEN
AND WHERE ARE STILL VERY UNCLEAR.
WHILE LAST NIGHT`S FORECAST HAD SATURDAY NIGHT THROUGH SUNDAY IN
THE PERIOD WITH THE BEST CHANCES FOR ACCUMULATING SNOW...THIS HAS
CHANGED...WITH SUNDAY NIGHT INTO TUESDAY WITH THE LARGER CONCERN.
THIS IS NOT OVERLY UNEXPECTED WITH THE SLOWER SOLUTION. SO AS TO
NOT FLIP FLOP ON THE FORECAST HAVE KEPT PRECIPITATION CHANCES FOR
SATURDAY AND SUNDAY...BUT WITH THE CURRENT GUIDANCE...CHANCES ARE
MUCH LESS. A COLD FRONT WILL MOVE THROUGH VERY EARLY SATURDAY
MORNING WHICH WILL DROP TEMPERATURES WITH BREEZY NORTH WINDS. THIS
WILL CAUSE HIGHS FOR THE REMAINDER OF THE FORECAST TO BE IN THE
20S.
THE GFS DID SLOW TO CONVERGE ON A SOLUTION SIMILAR TO THE
ECMWF...BUT IT STILL EJECTS THE DISTURBANCE NORTHEASTWARD QUICKER
ON MONDAY MORNING. WHEREAS THE ECMWF PULLS THE UPPER LOW AND
ASSOCIATED SURFACE LOW ACROSS THE AREA MONDAY NIGHT INTO TUESDAY.
THE SLOWER SOLUTION ALLOWS THE TEMPERATURES TO REMAIN COLD ENOUGH
THROUGHOUT THE COLUMN FOR SNOW TO BE THE MAIN PRECIPITATION TYPE
AFTER THE TRANSITION WITH THE COLD FRONT ON SATURDAY THROUGH THE
REMAINDER OF THE WEEKEND INTO EARLY NEXT WEEK.
DUE TO THE LOW CONFIDENCE WITH MODEL DISCREPANCIES...STILL THINK
SOME TRAVEL THROUGH THE CENTRAL AND SOUTHERN PLAINS WILL BE
HAZARDOUS FOR PORTIONS OF THE HOLIDAY WEEKEND. IT IS STILL TOO
EARLY TO SPECULATE ON SNOW ACCUMULATIONS...ESPECIALLY WITH THE
MODEL CHANGES...BUT SNOW ACCUMULATION IS POSSIBLE THIS WEEKEND
INTO THE BEGINNING OF THE WEEK. STAY TUNED TO THE FORECASTS AS IT
CONTINUES TO EVOLVE AND THE DETAILS ARE REFINED.
&&
.AVIATION...(FOR THE 12Z KGRI/KEAR TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 513 AM CST WED DEC 23 2015
THERE WILL BE A FEW LOWER CLOUDS AND MAYBE A SPRINKLE THIS MORNING
BUT THAT WILL MOVE TO THE EAST AND HAVE SOME SUN FOR THE
AFTERNOON. CLOUDS WILL RETURN TO THE AREA LATE THIS AFTERNOON AND
EVENING AND LATE TONIGHT EXPECT SOME MVFR CEILINGS AND VISIBILITY
WITH A CHANCE FOR SOME SNOW.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...JCB
LONG TERM...BILLINGS WRIGHT
AVIATION...JCB
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1045 AM EST WED DEC 23 2015
.SYNOPSIS...
NEAR RECORD WARMTH FOR MOST OF THE UPCOMING WEEK DESPITE SOME
FAIRLY CLOUDY CONDITIONS. HIGH CHANCE FOR SHOWERS AND ISOLATED
THUNDERSTORMS TODAY...WITH COVERAGE BECOMING MORE ISOLATED DURING
THURSDAY. DRY MID LEVEL AIR SHOULD SHUT DOWN SHOWER ACTIVITY
FRIDAY AND OVER THE WEEKEND AS HIGH PRESSURE OFF THE SOUTHEAST
COAST CONTINUES TO RIDGE ACROSS THE AREA.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 AM WEDNESDAY...ACTIVE PATTERN CONTINUES TODAY WITH
BERMUDA HIGH CONTINUING LOW LEVEL SOUTHERLY FLOW AND BROAD 5H
TROUGH AXIS TO THE WEST ENSURING FLOW ALOFT REMAINS SOUTHWEST.
THE RESULT IS DEEP MOISTURE OVER THE SOUTHEAST. PWATS IN FORECAST
SOUNDINGS APPROACH 2 INCHES THIS EVENING AND THE 12Z FLIGHT FROM
CHS REPORTED A PWAT OF 1.86...CLOSE TO 0.30 INCH ABOVE THE
PREVIOUS HIGH FOR THIS DATE. IN ADDITION TO THE ABUNDANT MOISTURE
THERE WILL BE A SERIES OF WEAK SHORTWAVES MOVING THROUGH THE FLOW
ALOFT. GUIDANCE ALSO SHOWS A WEAK JET STREAK IN THE 200-300 MB
LAYER WHICH MAY ENHANCE LIFT LATER THIS AFTERNOON AND EVENING.
IN ADDITION TO THE DYNAMICS THERE IS SOME SURFACE BASED
INSTABILITY. CAPE WILL PEAK AROUND 1500 J/KG BUT INSTABILITY
WITHIN REGIONS FAVORED FOR DEEPER CONVECTION AND LIGHTNING IS
LIMITED. HELD ONTO ISOLATED THUNDER BUT MOST AREAS ARE NOT LIKELY
TO EXPERIENCE ANY. ALTHOUGH A HIGH POP IS WARRANTED TODAY AND
TONIGHT COVERAGE WILL BE LIMITED AT ANY ONE TIME GIVEN THE
CONVECTIVE NATURE OF THE PRECIP. STRONG LOW LEVEL JET IN PLACE
TODAY WITH WINDS OF 30 TO 35 KT AROUND 1K FT. THUS FAR THE STABLE
SURFACE LAYER HAS PREVENTED STRONGER WINDS FROM BEING MIXED DOWN
BUT CANNOT RULE OUT AN ISOLATED STRONG/SEVERE STORM OR TWO IN THE
AFTERNOON. TEMPERATURES CONTINUE TO RUN WELL ABOVE CLIMO WITH
HIGHS IN THE MID 70S EXPECT ACROSS MUCH OF THE AREA.
DISCUSSION FROM 630 THIS MORNING FOLLOWS:
LATEST LOCAL AND MOSAIC RADAR DATA INDICATES PCPN CONTINUES TO
STREAM UP TO THE NNE ACROSS THE CAROLINAS. THIS IS IN RESPONSE TO
A MIDLEVEL S/W TROF LIFTING N TO NE WITHIN STRONG MID- LEVEL SSW
FLOW. THE BEST OR MAIN DYNAMICS FROM THIS S/W TROF STAY WEST OF
THE ILM CWA TODAY...BUT MODELS INDICATE THE TRAILING MID- LEVEL
SHEARED AXIS WILL MAKE ITS WAY TO THE CAROLINA COASTS BY LATE THIS
EVENING. DEEP GULF OF MEXICO AND ATLANTIC MOISTURE WILL CONTINUE
TO PUMP ACROSS THE ILM CWA WITH PROGGED PWS IN THE 1.5 TO 2.00
INCH RANGE. TO PUT IT ALL TOGETHER...THE FA WILL BE UNDER THE
LIKELY TO CATEGORICAL POP THREAT FROM SHOWERS AND EMBEDDED
ISOLATED THUNDERSTORMS TODAY THRU THIS EVENING. AVBL CAPE OF 1K TO
POSSIBLY 1.25K WILL BE LOW ALTHOUGH BETTER THAN YESTERDAY...AND
WITH PROGGED LAPSE RATES REMAINING SUSPECT...HAVE KEPT THE TSTORM
THREAT TO ISOLATED AT BEST FOR NOW.
NO FLOOD WATCHES ARE FORECAST FOR THE ILM CWA. HOWEVER...ANY
TRAINING OF HEAVY SHOWERS OVER AREAS RECEIVING A GOOD DOSE OF
RAINFALL FROM TUESDAY...COULD RESULT IN PONDING OF WATER
ESPECIALLY ACROSS LOW LYING AREAS AND PRONE ROADWAYS. WILL
HIGHLIGHT THIS IN THE HAZARDOUS WEATHER OUTLOOK.
TEMPS WILL CONTINUE TO RUN 15 TO 25+ DEGREES ABOVE NORMAL.
TODAYS HIGHS IN THE MID TO UPPER 70S AND TONIGHTS LOWS IN THE MID
TO UPPER 60S. THIS SOUNDS MORE LIKE A MID FALL OR MID SPRING TEMP
FORECAST. OF NOTE...NORMAL HIGHS ARE IN THE MID TO UPPER 50S AND
NORMAL LOWS ARE IN LOW TO MID 30S.
&&
.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
AS OF 3 AM WEDNESDAY...PATTERN CONSISTENCY MORE TYPICAL OF THE WARM
SEASON IN PLACE THROUGH THE PERIOD WITH UPPER RIDGE AND BERMUDA HIGH-
LIKE SURFACE LOCKING INTO PLACE. NO SURPRISE THEN THAT THE
ATMOSPHERE WILL BE PRIMED WITH BOTH COPIOUS WARMTH AND MOISTURE. THE
WARMTH WILL MANIFEST ITSELF AS, WELL, WARMTH. NEAR RECORD VALUES, IN
FACT. THE MOISTURE WILL MOSTLY TAKE FORM OF FAIRLY WIDESPREAD CLOUD
COVER BUT ALSO SOME VERY LOW RAIN CHANCES. THESE LOW RAIN CHANCES
WILL BE FOCUSED ALONG WESTERN ZONES ON THURSDAY AS A WEAK VORT
STREAKS BY COINCIDING WITH A RIBBON OF THE DEEPEST MOISTURE. (THE
OFFSHORE QPF POSSIBLY AFFECTING THE COAST DEPICTED ON THE WRF SEEMS
IMPLAUSIBLE GIVEN THE WARM AIR BEING STABILIZED BY THE CHILLY SSTS).
IT MAY THEN SHIFT TO NORTHERN AND WESTERN ZONES AS A COLD FRONT
BACKDOORS ITS WAY TO THE NC/VA BORDER. OVERALL THOUGH FEEL THAT
FRIDAY MOSTLY RAIN-FREE AS THE RIDGE ALOFT BUILDS WESTWARD PUMPING
HEIGHT RISES INTO THE REGION SUPPRESSING WHAT MAY ALSO BE AN ATTEMPT
AT SEA BREEZE AND WEST WALL CONVECTION SHOWN IN SOME MODELS.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 3 AM WEDNESDAY... MODERATELY HIGHLY AMPLIFIED PATTERN IN PLACE
FOR THE ENTIRE PERIOD. STALWART RIDGE ALOFT HOLDS JUST EAST OF THE
BAHAMAS WHILE CUTOFF UPPER LOW EJECTS FROM THE SOUTHWESTERN U.S.
INTO THE OHIO VALLEY SATURDAY THROUGH MONDAY. TEMPERATURES WILL
CONTINUE THEIR IMPRESSIVE DEVIATIONS FROM CLIMATOLOGY WITH DAYTIME
HIGHS NEARLY 20 DEGREES ABOVE NORMAL AND NIGHTTIME DEVIATIONS OFTEN
EVEN LARGER AS CLOUD COVER LINGERS BENEATH THE SUBSIDENCE INVERSION
BORNE OF THE UPPER RIDGE. RAIN CHANCES ARE BOTH TOUGH TO RULE OUT
WITH SO MUCH LOW LEVEL MOISTURE BUT ALSO HARD TO GET EXCITED ABOUT
DUE TO THE UPPER RIDGE. THE EXCEPTION MAY BE MONDAY WHEN THE RIDGE
GETS BEAT DOWN SUFFICIENTLY FOR SOME HEIGHT FALLS LOCALLY. THEN
AGAIN, THIS USUALLY OCCURS MORE SLOWLY THAN PORTRAYED IN GUIDANCE.
&&
.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
AS OF 12Z...THE HRRR MODEL INITIALIZED REASONABLY WELL AND BRINGS
THE FOCUS OF THE PRECIP TO THE COAST BY LATE MORNING. CEILINGS ARE
A BIT ALL OVER THE PLACE...AS WELL AS THE VISIBILITIES IN THE HEAVIER
PRECIP. CEILINGS TODAY WILL BOUNCE FROM IFR TO VFR WITH VISIBILITIES
BRIEFLY IFR IN THE HEAVIER EMBEDDED CONVECTION. MID AND HIGH LEVEL
MOISTURE WILL CONTINUE THROUGH THE END OF THE FORECAST PERIOD. THE
SOUTHERLY GRADIENT WILL REMAIN TIGHT...WITH GUST TO 20 KTS EXPECTED
AT ANY TIME DURING THE NEXT 24 HOURS. A RUMBLE OF THUNDER CAN NOT
BE RULED OUT.
EXTENDED OUTLOOK...POSSIBLE MVFR TO IFR CONDITIONS IN PCPN AND LOW
CEILINGS FROM THROUGH THURSDAY...OTHERWISE EXPECT VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 AM WEDNESDAY...SCA CONTINUES FOR ALL ZONES WITH
CONTINUED AND INCREASING SOUTHERLY FLOW BUILDING SEAS OVER 6 FT
ACROSS PORTIONS OF ALL MARINE ZONES. BERMUDA HIGH REMAINS THE MAIN
SURFACE FEATURE...KEEPING WINDS FROM THE SOUTH. COMBINATION OF
GRADIENT AND LOW LEVEL JET IS KEEPING SPEEDS IN THE 15 TO 20 KT
RANGE THROUGH THE PERIOD. ONLY MINIMAL CHANGES REQUIRED FOR
MORNING UPDATE.
DISCUSSION FROM 630 THIS MORNING FOLLOWS:
SMALL CRAFT ADVISORY CONDITIONS EXPECTED THRU THIS PERIOD. SFC
PRESSURE PATTERN THRU TONIGHT TO YIELD SSE-S WIND DIRECTIONS THIS
MORNING...BECOMING S-SSW BY MIDDAY AND CONTINUING THRU TONIGHT. A
TIGHTENING SFC PG WILL DEVELOP ACROSS THE LOCAL WATERS EARLY
TODAY...AND WILL REMAIN TIGHTENED THRU TONIGHT. THIS WILL YIELD 10
TO 20 KT SUSTAINED WIND SPEEDS THIS MORNING THAT COULD
OCCASIONALLY REACH 15 TO 25 KT FROM MIDDAY THROUGH THIS EVENING.
IN ADDITION...GUSTS COULD APPROACH 30 KT ESPECIALLY OVER SSTS THAT
ARE WELL INTO THE 60S. LOCAL SSTS HAVE ALREADY SHOWN AN INCREASE
FROM 24 HRS AGO DUE TO THE ONSHORE FLOW WITH LOW 60S COMMON NOW.
EXPECT THIS SLOW INCREASING TREND TO CONTINUE WITH LOW TO MID 60S
BECOMING MORE COMMON BY EARLY THU. AS A RESULT...SEA FOG
DEVELOPMENT SHOULD NOT BE AN ISSUE DURING THIS TIME PERIOD.
SIGNIFICANT SEAS WILL BUILD TO 4 TO 7 FT TODAY...AND PEAK 5 TO
8 FT LATE THIS AFTN THRU TONIGHT. THE 8 FOOTERS WILL PRIMARILY
OCCUR OVER THE WATERS OFF CAPE FEAR. WIND DRIVEN WAVES AT 6 TO 7
SECOND PERIODS WILL DOMINATE THE SEAS.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 3 AM WEDNESDAY... PERIOD INITIALIZES WITH A SMALL CRAFT
ADVISORY IN A MODERATELY PINCHED SOUTHWESTERLY GRADIENT FLOW WITH
SOME EMBEDDED ENERGY. A SLIGHT WESTWARD EXTENSION OF A RIDGE AXIS
INTO GA/FL ON THE PART OF THE OFFSHORE HIGH LEADS TO A SLIGHT
WEAKENING OF THE GRADIENT LATER THURSDAY INTO THURSDAY NIGHT AND
FRIDAY. WIND REMAINS MOSTLY SOUTHWESTERLY ON FRIDAY BUT IN A
LIGHTENED STATE. THE RIDGE AXIS SHOULD ALSO DISRUPT THE SWELL
ENERGY A BIT TO HELP FURTHER REDUCE DOMINANT WAVE HEIGHT.
LONG TERM /SATURDAY THROUGH SUNDAY/...
AS OF 3 AM WEDNESDAY... MUCH MORE OF A WARM SEASON PATTERN IN
PLACE WITH A WEST ATLANTIC HIGH DOMINATING AND A COMPLETE LACK OF
ANY FRONTS. THE MAIN DIFFERENCE PATTERN-WISE WILL BE THAT THE HIGH
WILL BE WEAKER AND FURTHER WEST THAN WHAT IS NORMALLY OBSERVED IN
THE WARM SEASON. AS SUCH WIND SPEEDS MAY WELL BE CAPPED AT 10KT AS
THE DIRECTION REMAINS SOUTH TO SOUTHWESTERLY. SEAS WILL AVERAGE 2
TO 3 AND OCCASIONALLY (WELL OFFSHORE) 4 FT.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL NOON EST THURSDAY FOR AMZ250-252-
254-256-270-274.
&&
$$
NEAR TERM...III
SHORT TERM...MBB
LONG TERM...MBB
AVIATION...DL
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1040 AM EST WED DEC 23 2015
.SYNOPSIS...A WEDGE FRONT WILL REMAIN QUASI-STATIONARY OVER THE
PIEDMONT EARLY TODAY...THEN BE OVERTAKEN BY A MARITIME WARM FRONT
THAT WILL SURGE ACROSS THE CAROLINAS AND SOUTHEASTERN VIRGINIA THIS
AFTERNOON. ANOMALOUSLY STRONG SUB-TROPICAL HIGH PRESSURE OVER THE
WEST-CENTRAL ATLANTIC OCEAN WILL THEN DIRECT UNSEASONABLY WARM AND
MOIST SOUTHERLY FLOW THROUGHOUT THE SOUTHEASTERN UNITED STATES
THROUGH CHRISTMAS.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1040 AM WEDNESDAY...
...FLASH FLOOD WATCH CONTINUES ACROSS THE WESTERN PIEDMONT...
DEEP MOIST SOUTHERLY FLOW...CHARACTERIZED BY NEARLY CLIMATOLOGICAL MAX
PW OF 1.8 INCHES AND 850MB DEWPOINTS OF 14-15C...CONTINUES AROUND THE
ANOMALOUSLY STRONG RIDGE OVER THE WESTERN ATLANTIC. A WEDGE FRONT
IS HOLDING FROM CENTRAL VA THROUGH THE NC WESTERN PIEDMONT AND INTO
UPSTATE SC...WHILE A COASTAL WARM FRONT IS BEGINNING TO SURGE INLAND
AS UPPER 60S DEWPOINTS HAVE REACHED THE I-95 CORRIDOR. IN THE WEDGE
AIRMASS...DENSE FOG WILL CONTINUE...PERIODICALLY DISPERSED BY
SHOWERS SPREADING NORTH THROUGH THE PIEDMONT. NEARLY ALL GUIDANCE
SHOWS THE WEDGE FRONT ERODING AND 60S DEWPOINTS ALL THE WAY THROUGH
FORSYTH CO THIS AFTERNOON. MEANWHILE...THE WARM FRONT AND LEADING
EDGE OF WEAKLY UNSTABLE AIR...WITH MLCAPE POTENTIALLY EXCEEDING 500
J/KG...WILL ALSO CONTINUE INLAND...ALTHOUGH WITH RAIN ALMOST
CONTINUOUS IN THE PIEDMONT IT`S STILL A LITTLE UNCLEAR HOW FAR
INLAND THE WARM SECTOR WILL MIX. DEEP LAYER SHEAR WILL BE 45-
50KT...WHICH WILL SUPPORT A SEVERE THREAT OVER THE COASTAL PLAIN
WHERE THE SHEAR/INSTABILITY PARAMETER SPACE IS BEST. LOW-LEVEL IS
ENHANCED BY A 40KT SOUTHWESTERLY LLJ AND SOUTHEASTERLY SURFACE
WIND...ESPECIALLY IN THE VICINITY OF THE WARM FRONT...AND SHERBE
VALUES ARE PROGGED AROUND 1 THROUGH THE PIEDMONT THIS AFTERNOON.
GOING AGAINST THE SEVERE THREAT IS A GENERAL LACK OF A FOCUS...AS A
NOTABLE MCV OVER NORTHERN GA SHOULD MOVE MORE ALONG THE
MOUNTAINS...AND RAP SOUNDINGS MAINTAIN A SMALL CAPPING INVERSION
THROUGH THE AFTERNOON THAT WOULD LIMIT THE ALREADY WEAK MUCAPE.
HOWEVER...THE SPC MARGINAL RISK STILL LOOKS WARRANTED GIVEN THE
ANOMALOUSLY HIGH PW AND UNUSUAL AIRMASS FOR LATE DECEMBER.
THE FLOODING THREAT...WHILE IT HASN`T MATERIALIZED IN THE
WEST...STILL EXISTS GIVEN THE AFOREMENTIONED MCV MOVING UP FROM GA.
THE HRRR SHOWS A LARGE AREA OF PRECIP...INCREASINGLY CONVECTIVE
LOOKING...OVER THE WESTERN PIEDMONT THIS AFTERNOON. IN ADDITION...A
FEW RIVERS...INCLUDING THE ROCKY RIVER AND HAW RIVER...ARE EITHER
EXPERIENCING MINOR FLOODING OR FORECAST TO FLOOD. SO WE WILL
CONTINUE THE FLASH FLOOD WATCH FOR NOW.
TEMPS WILL SLOWLY RISE THROUGH THE 60S IN THE PIEDMONT AND INTO THE
70S IN THE COASTAL PLAIN...WITH MAX VALUES IN THE 65-75 RANGE THIS
AFTERNOON. -22
SHOWERS WILL CONTINUE TO BE A POSSIBILITY TONIGHT...AND LOW
TEMPERATURES WILL STRUGGLE TO DROP OUT OF THE 70S AT MOST
LOCATIONS...AGAIN HAVING A GOOD CHANCE OF MATCHING THE ALL-TIME
WARMEST DECEMBER MINIMUM TEMPERATURE ON RECORD(RDU-69...FAY-69...GSO-
65).
&&
.SHORT TERM /THURSDAY AND THURSDAY NIGHT/...
AS OF 355 AM WEDNESDAY...
ON THE WESTERN PERIPHERY OF ANOMALOUSLY STRONG SUB-TROPICAL RIDGING
CENTERED OVER THE WEST-CENTRAL ATLANTIC...SHORTWAVE RIDGING AND
ASSOCIATED HEIGHT RISES ALOFT WILL BUILD BEHIND THE MAIN SHORTWAVE
TROUGH LIFTING INTO EASTERN CANADA. WITH RIDGING ALOFT AND AN
ASSOCIATED PROBABLE CAPPING INVERSION DEPICTED ON NAM BUFR
SOUNDINGS...THE DAY WILL LIKELY BE A DRY ONE...THOUGH DIURNAL
HEATING OF THE UNSEASONABLY WARM (70S TO AROUND 80 IN IN THE I-95
CORRIDOR) AND HUMID BOUNDARY LAYER MAY ALLOW FOR SOME CU TO BYPASS
THE CAP AND GROW INTO ISOLATED SHOWERS/STORMS. IN ADDITION...AN
UPSTREAM QLCS...IN A REGION OF RESIDUALLY STRONG H85 MOISTURE
TRANSPORT DIRECTED INTO THE TN VALLEY...MAY SUPPORT THE EASTWARD
PROGRESSION OF A WEAKENING LONE OF SHOWERS AND STORMS TO CROSS THE
APPALACHIANS AND DRIFT INTO WESTERN NC...INCLUDING THE WESTERN
PIEDMONT EARLY THU NIGHT. INCREASING CINH WITH NOCTURNAL "COOLING"
INTO THE 60S FAVORS A DRY NIGHT OTHERWISE AND ELSEWHERE.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 410 AM WEDNESDAY...
THE STRONG SUB-TROPICAL RIDGE...WITH ANOMALOUSLY HIGH HEIGHTS AND
PRECIPITABLE WATER VALUES BETWEEN 200-300 PERCENT OF NORMAL FROM THE
SOUTHEASTERN UNITED STATES TO EAST-CENTRAL CANADA...WILL MAINTAIN A
VERY MILD-WARM REGIME ACROSS THE SOUTHEASTERN STATES THROUGHOUT THE
PERIOD...AND A WET ONE PRIMARILY NORTHWEST OF CENTRAL NC...AT LEAST
UNTIL LATE IN THE PERIOD. THE MAIN FORECAST UNCERTAINTY REMAINS THE
POSITIONING OF A WAVY FRONTAL ZONE FORECAST TO MEANDER ACROSS THE
MIDDLE ATLANTIC STATES...AND CONSEQUENTLY HOW MUCH SUPPRESSION OF
THE WARMTH OCCURS EAST OF THE APPALACHIANS...DICTATED BY A BATTLE
BETWEEN THE SUB-TROPICAL RIDGE AND CONFLUENT SPLIT FLOW
ALOFT/UNDERLYING POLAR HIGHS FORECAST TO DEVELOP ACROSS THE GREAT
LAKES AND NEW ENGLAND BY THIS WEEKEND.
THE TIMING OF POTENTIAL COLD FRONTAL SURGES INTO NC...IF THEY
OCCUR...ARE FAVORED LATE FRI NIGHT-SAT...AND AGAIN SUN NIGHT-
MON...WITH THE FORMER APPEARING INCREASINGLY UNLIKELY TO AFFECT
CENTRAL NC. OTHERWISE UNSEASONABLY MILD-WARM AND HUMID CONDITIONS IN
DEEP SOUTHERLY FLOW AROUND THE SUB-TROPICAL RIDGE WILL PREVAIL. THE
PRIMARY BRANCH OF THE NORTHERN STREAM WILL BE BLOCKED TO THE NW BY
THE SUB-TROPICAL RIDGING...SO FORCING FOR ASCENT AND ASSOCIATED
PRECIPITATION CHANCES WILL REMAIN LOW (GENERALLY AOB 20 PERCENT) AND
INSTEAD DRIVEN BY LOWER AMPLITUDE SOUTHERN STREAM PERTURBATIONS AND
ASSOCIATED SURGES OF LOW LEVEL THETA-E ADVECTION AND BRIEF EROSION
OF A CAPPING INVERSION FRI-SAT...WITH SAID CAPPING MORE LIKELY TO BE
OVERCOME BY DIURNAL HEATING IN AN AIRMASS MORE CHARACTERISTIC OF
APRIL-MAY THAN LATE DECEMBER.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
AS OF 720 AM WEDNESDAY...
24 HOUR TAF PERIOD: WIDESPREAD ADVERSE AVIATION CONDITIONS WILL
PERSIST THROUGH THE 24 HOUR TAF PERIOD AS AN ANOMALOUSLY MOIST AND
WARM AIRMASS ADVECTS INTO THE AREA.
CEILINGS HAVE IMPROVED TO MVFR AND EVEN VFR ACROSS CENTRAL AND EASTERN
PORTIONS OF THE FORECAST AS WARM SECTOR OVERTAKES THE AREA FROM THE
SOUTH. HOWEVER WE ARE STILL SEEING SOME IFR AND LIFR VISIBILITY
RESTRICTIONS WITH THE HEAVIER SHOWERS. CONDITIONS WILL BE UP AND
DOWN TODAY...BOUNCING FROM VFR TO IFR WITH SCATTERED TO NUMEROUS
SHOWERS AND STORMS EXPECTED THIS AFTERNOON AND EVENING AS WE
DESTABILIZE.
CONDITIONS WILL BE SLOWER TO IMPROVE AT KINT AND KGSO...PERHAPS
IMPROVING TO MVFR BY THE EARLY AFTERNOON AS THE WARM AIR AND
INCREASING INSTABILITY FINALLY HELP TO SCOUR OUT THE LINGERING
WEDGE AIRMASS.
ADDITIONALLY...SOUTHERLY WINDS WILL INCREASE...GUSTING UP TO 20 TO
25 KTS...STRONGEST IN THE EAST.
CEILINGS SHOULD QUICKLY DETERIORATE TO IFR TO LIFR ACROSS THE AREA THIS
EVENING...THOUGH A STEADY 10 TO 15KT SOUTHERLY BREEZE SHOULD
PRECLUDE WIDESPREAD FOG DEVELOPMENT.
OUTLOOK: A MOIST DEEP SOUTHWESTERLY FLOW DOWNSTREAM OF THE LONG WAVE
TROUGH IN PLACE ACROSS THE CENTRAL CONUS WILL SUPPORT A PROLONGED
PERIOD OF ADVERSE AVIATION CONDITIONS THROUGH MUCH OF THE PERIOD.
SUB-VFR CONDITIONS IN LOW CLOUDS/STRATUS WILL ALSO BE LIKELY EACH
MORNING... ALONG WITH THE TREAT OF SOME SHOWERS EACH DAY.
&&
.CLIMATE...
HERE ARE THE AREA RECORD MAXIMUMS AND HIGH MINIMUMS FOR DECEMBER 24TH
AND 25TH. RECORDS HAVE BEEN KEPT IN THE GREENSBORO AREA SINCE
1903... IN THE RALEIGH AREA SINCE 1887... AND IN THE FAYETTEVILLE
AREA SINCE 1910.
DEC 24: RECORD MAXIMUM HIGH MINIMUM
GREENSBORO 71 (1964) 52 (1904)
RALEIGH 75 (1931) 59 (1891)
FAYETTEVILLE 78 (1931) 66 (1990)
DEC 25: RECORD MAXIMUM HIGH MINIMUM
GREENSBORO 74 (1955) 58 (1932)
RALEIGH 75 (1955) 63 (1932)
FAYETTEVILLE 79 (1932) 68 (1932)
&&
.RAH WATCHES/WARNINGS/ADVISORIES... NONE.
&&
$$
SYNOPSIS...2
NEAR TERM...CBL/22
SHORT TERM...2
LONG TERM...2
AVIATION...CBL
CLIMATE...HARTFIELD/BLAES
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1030 AM EST WED DEC 23 2015
.SYNOPSIS...A WEDGE FRONT WILL REMAIN QUASI-STATIONARY OVER THE
PIEDMONT EARLY TODAY...THEN BE OVERTAKEN BY A MARITIME WARM FRONT
THAT WILL SURGE ACROSS THE CAROLINAS AND SOUTHEASTERN VIRGINIA THIS
AFTERNOON. ANOMALOUSLY STRONG SUB-TROPICAL HIGH PRESSURE OVER THE
WEST-CENTRAL ATLANTIC OCEAN WILL THEN DIRECT UNSEASONABLY WARM AND
MOIST SOUTHERLY FLOW THROUGHOUT THE SOUTHEASTERN UNITED STATES
THROUGH CHRISTMAS.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 AM WEDNESDAY...
...FLASH FLOOD WATCH CONTINUES ACROSS THE WESTERN PIEDMONT...
DEEP MOIST SOUTHERLY FLOW...CHARACTERIZED BY NEARLY CLIMATOLOGICAL MAX
PW OF 1.8 INCHES AND 850MB DEWPOINTS OF 14-15C...CONTINUES AROUND THE
ANOMALOUSLY STRONG RIDGE OVER THE WESTERN ATLANTIC. A WEDGE FRONT
IS HOLDING FROM CENTRAL VA THROUGH THE NC WESTERN PIEDMONT AND INTO
UPSTATE SC...WHILE A COASTAL WARM FRONT IS BEGINNING TO SURGE INLAND
AS UPPER 60S DEWPOINTS HAVE REACHED THE I-95 CORRIDOR. IN THE WEDGE
AIRMASS...DENSE FOG WILL CONTINUE...PERIODICALLY DISPERSED BY
SHOWERS SPREADING NORTH THROUGH THE PIEDMONT. NEARLY ALL GUIDANCE
SHOWS THE WEDGE FRONT ERODING AND 60S DEWPOINTS ALL THE WAY THROUGH
FORSYTH CO THIS AFTERNOON. MEANWHILE...THE WARM FRONT AND LEADING
EDGE OF WEAKLY UNSTABLE AIR...WITH MLCAPE POTENTIALLY EXCEEDING 500
J/KG...WILL ALSO CONTINUE INLAND...ALTHOUGH WITH RAIN ALMOST
CONTINUOUS IN THE PIEDMONT IT`S STILL A LITTLE UNCLEAR HOW FAR
INLAND THE WARM SECTOR WILL MIX. DEEP LAYER SHEAR WILL BE 45-
50KT...WHICH WILL SUPPORT A SEVERE THREAT OVER THE COASTAL PLAIN
WHERE THE SHEAR/INSTABILITY PARAMETER SPACE IS BEST. LOW-LEVEL IS
ENHANCED BY A 40KT SOUTHWESTERLY LLJ AND SOUTHEASTERLY SURFACE
WIND...ESPECIALLY IN THE VICINITY OF THE WARM FRONT...AND SHERBE
VALUES ARE PROGGED AROUND 1 THROUGH THE PIEDMONT THIS AFTERNOON.
GOING AGAINST THE SEVERE THREAT IS A GENERAL LACK OF A FOCUS...AS A
NOTABLE MCV OVER NORTHERN GA SHOULD MOVE MORE ALONG THE
MOUNTAINS...AND RAP SOUNDINGS MAINTAIN A SMALL CAPPING INVERSION
THROUGH THE AFTERNOON THAT WOULD LIMIT THE ALREADY WEAK MUCAPE.
HOWEVER...THE SPC MARGINAL RISK STILL LOOKS WARRANTED GIVEN THE
ANOMALOUSLY HIGH PW AND UNUSUAL AIRMASS FOR LATE DECEMBER.
TEMPS WILL SLOWLY RISE THROUGH THE 60S IN THE PIEDMONT AND INTO THE
70S IN THE COASTAL PLAIN...WITH MAX VALUES IN THE 65-75 RANGE THIS
AFTERNOON. -22
SHOWERS WILL CONTINUE TO BE A POSSIBILITY TONIGHT...AND LOW
TEMPERATURES WILL STRUGGLE TO DROP OUT OF THE 70S AT MOST
LOCATIONS...AGAIN HAVING A GOOD CHANCE OF MATCHING THE ALL-TIME
WARMEST DECEMBER MINIMUM TEMPERATURE ON RECORD(RDU-69...FAY-69...GSO-
65).
&&
.SHORT TERM /THURSDAY AND THURSDAY NIGHT/...
AS OF 355 AM WEDNESDAY...
ON THE WESTERN PERIPHERY OF ANOMALOUSLY STRONG SUB-TROPICAL RIDGING
CENTERED OVER THE WEST-CENTRAL ATLANTIC...SHORTWAVE RIDGING AND
ASSOCIATED HEIGHT RISES ALOFT WILL BUILD BEHIND THE MAIN SHORTWAVE
TROUGH LIFTING INTO EASTERN CANADA. WITH RIDGING ALOFT AND AN
ASSOCIATED PROBABLE CAPPING INVERSION DEPICTED ON NAM BUFR
SOUNDINGS...THE DAY WILL LIKELY BE A DRY ONE...THOUGH DIURNAL
HEATING OF THE UNSEASONABLY WARM (70S TO AROUND 80 IN IN THE I-95
CORRIDOR) AND HUMID BOUNDARY LAYER MAY ALLOW FOR SOME CU TO BYPASS
THE CAP AND GROW INTO ISOLATED SHOWERS/STORMS. IN ADDITION...AN
UPSTREAM QLCS...IN A REGION OF RESIDUALLY STRONG H85 MOISTURE
TRANSPORT DIRECTED INTO THE TN VALLEY...MAY SUPPORT THE EASTWARD
PROGRESSION OF A WEAKENING LONE OF SHOWERS AND STORMS TO CROSS THE
APPALACHIANS AND DRIFT INTO WESTERN NC...INCLUDING THE WESTERN
PIEDMONT EARLY THU NIGHT. INCREASING CINH WITH NOCTURNAL "COOLING"
INTO THE 60S FAVORS A DRY NIGHT OTHERWISE AND ELSEWHERE.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 410 AM WEDNESDAY...
THE STRONG SUB-TROPICAL RIDGE...WITH ANOMALOUSLY HIGH HEIGHTS AND
PRECIPITABLE WATER VALUES BETWEEN 200-300 PERCENT OF NORMAL FROM THE
SOUTHEASTERN UNITED STATES TO EAST-CENTRAL CANADA...WILL MAINTAIN A
VERY MILD-WARM REGIME ACROSS THE SOUTHEASTERN STATES THROUGHOUT THE
PERIOD...AND A WET ONE PRIMARILY NORTHWEST OF CENTRAL NC...AT LEAST
UNTIL LATE IN THE PERIOD. THE MAIN FORECAST UNCERTAINTY REMAINS THE
POSITIONING OF A WAVY FRONTAL ZONE FORECAST TO MEANDER ACROSS THE
MIDDLE ATLANTIC STATES...AND CONSEQUENTLY HOW MUCH SUPPRESSION OF
THE WARMTH OCCURS EAST OF THE APPALACHIANS...DICTATED BY A BATTLE
BETWEEN THE SUB-TROPICAL RIDGE AND CONFLUENT SPLIT FLOW
ALOFT/UNDERLYING POLAR HIGHS FORECAST TO DEVELOP ACROSS THE GREAT
LAKES AND NEW ENGLAND BY THIS WEEKEND.
THE TIMING OF POTENTIAL COLD FRONTAL SURGES INTO NC...IF THEY
OCCUR...ARE FAVORED LATE FRI NIGHT-SAT...AND AGAIN SUN NIGHT-
MON...WITH THE FORMER APPEARING INCREASINGLY UNLIKELY TO AFFECT
CENTRAL NC. OTHERWISE UNSEASONABLY MILD-WARM AND HUMID CONDITIONS IN
DEEP SOUTHERLY FLOW AROUND THE SUB-TROPICAL RIDGE WILL PREVAIL. THE
PRIMARY BRANCH OF THE NORTHERN STREAM WILL BE BLOCKED TO THE NW BY
THE SUB-TROPICAL RIDGING...SO FORCING FOR ASCENT AND ASSOCIATED
PRECIPITATION CHANCES WILL REMAIN LOW (GENERALLY AOB 20 PERCENT) AND
INSTEAD DRIVEN BY LOWER AMPLITUDE SOUTHERN STREAM PERTURBATIONS AND
ASSOCIATED SURGES OF LOW LEVEL THETA-E ADVECTION AND BRIEF EROSION
OF A CAPPING INVERSION FRI-SAT...WITH SAID CAPPING MORE LIKELY TO BE
OVERCOME BY DIURNAL HEATING IN AN AIRMASS MORE CHARACTERISTIC OF
APRIL-MAY THAN LATE DECEMBER.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
AS OF 720 AM WEDNESDAY...
24 HOUR TAF PERIOD: WIDESPREAD ADVERSE AVIATION CONDITIONS WILL
PERSIST THROUGH THE 24 HOUR TAF PERIOD AS AN ANOMALOUSLY MOIST AND
WARM AIRMASS ADVECTS INTO THE AREA.
CEILINGS HAVE IMPROVED TO MVFR AND EVEN VFR ACROSS CENTRAL AND EASTERN
PORTIONS OF THE FORECAST AS WARM SECTOR OVERTAKES THE AREA FROM THE
SOUTH. HOWEVER WE ARE STILL SEEING SOME IFR AND LIFR VISIBILITY
RESTRICTIONS WITH THE HEAVIER SHOWERS. CONDITIONS WILL BE UP AND
DOWN TODAY...BOUNCING FROM VFR TO IFR WITH SCATTERED TO NUMEROUS
SHOWERS AND STORMS EXPECTED THIS AFTERNOON AND EVENING AS WE
DESTABILIZE.
CONDITIONS WILL BE SLOWER TO IMPROVE AT KINT AND KGSO...PERHAPS
IMPROVING TO MVFR BY THE EARLY AFTERNOON AS THE WARM AIR AND
INCREASING INSTABILITY FINALLY HELP TO SCOUR OUT THE LINGERING
WEDGE AIRMASS.
ADDITIONALLY...SOUTHERLY WINDS WILL INCREASE...GUSTING UP TO 20 TO
25 KTS...STRONGEST IN THE EAST.
CEILINGS SHOULD QUICKLY DETERIORATE TO IFR TO LIFR ACROSS THE AREA THIS
EVENING...THOUGH A STEADY 10 TO 15KT SOUTHERLY BREEZE SHOULD
PRECLUDE WIDESPREAD FOG DEVELOPMENT.
OUTLOOK: A MOIST DEEP SOUTHWESTERLY FLOW DOWNSTREAM OF THE LONG WAVE
TROUGH IN PLACE ACROSS THE CENTRAL CONUS WILL SUPPORT A PROLONGED
PERIOD OF ADVERSE AVIATION CONDITIONS THROUGH MUCH OF THE PERIOD.
SUB-VFR CONDITIONS IN LOW CLOUDS/STRATUS WILL ALSO BE LIKELY EACH
MORNING... ALONG WITH THE TREAT OF SOME SHOWERS EACH DAY.
&&
.CLIMATE...
HERE ARE THE AREA RECORD MAXIMUMS AND HIGH MINIMUMS FOR DECEMBER 24TH
AND 25TH. RECORDS HAVE BEEN KEPT IN THE GREENSBORO AREA SINCE
1903... IN THE RALEIGH AREA SINCE 1887... AND IN THE FAYETTEVILLE
AREA SINCE 1910.
DEC 24: RECORD MAXIMUM HIGH MINIMUM
GREENSBORO 71 (1964) 52 (1904)
RALEIGH 75 (1931) 59 (1891)
FAYETTEVILLE 78 (1931) 66 (1990)
DEC 25: RECORD MAXIMUM HIGH MINIMUM
GREENSBORO 74 (1955) 58 (1932)
RALEIGH 75 (1955) 63 (1932)
FAYETTEVILLE 79 (1932) 68 (1932)
&&
.RAH WATCHES/WARNINGS/ADVISORIES... NONE.
&&
$$
SYNOPSIS...2
NEAR TERM...CBL/22
SHORT TERM...2
LONG TERM...2
AVIATION...CBL
CLIMATE...HARTFIELD/BLAES
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
1029 AM EST WED DEC 23 2015
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE OFFSHORE THROUGH THE WEEKEND. A WEAK
COLD FRONT WILL APPROACH FROM THE NORTH THURSDAY NIGHT THEN STALL
NEAR THE VIRGINIA BORDER FRIDAY. THE FRONT WILL LIFT BACK NORTH
OVER THE WEEKEND.
&&
.NEAR TERM /REST OF TODAY/...
AS OF 1020 AM WEDNESDAY...LATE MORNING UPDATE FOR ONLY MINOR
TWEAKS IN THE NEAR TERM. CONVECTION HAS SHOWN POTENTIAL TO BECOME
SEVERE FOR WESTERN ZONES (DUPLIN/ONSLOW/GREENE/LENOIR COUNTIES)
WHERE SPC MESOANALYSES INDICATE BETTER INSTABILITY. IR SATELLITE
IMAGERY INDICATED WARMING CLOUD TOPS AS THE EARLIER CONVECTION
SHIFTS NORTH ACROSS THE HWY 64 CORRIDOR. A PERIOD OF HEAVY RAIN
AND POSSIBLY GUSTY WINDS WILL STILL BE POSSIBLE INTO EARLY
AFTERNOON WITH SHOWER COVERAGE INCREASING FROM THE SOUTH AND WEST.
THE SYNOPTIC PATTERN PRESENTS AN UPPER TROUGH MOVING INTO THE
PLAINS WITH RIDGING OVER THE ATLANTIC, BRINGING DEEP SW FLOW
ACROSS THE EASTERN CONUS THAT IS TAPPING INTO TROPICAL PACIFIC
MOISTURE BRINGING PWATS AROUND 1.75 INCHES WHICH IS AT OR ABOVE
CLIMATOLOGICAL MAXIMUM FOR LATE DECEMBER. SFC HIGH PRES REMAINS
CENTERED OFFSHORE WITH A COASTAL TROUGH JUST SOUTH OF THE REGION
PROGGED TO LIFT ACROSS THE REGION TODAY. THIS PATTERN WILL
CONTINUE TO BRING PERIODS OF SHOWERS ACROSS THE REGION TODAY WHICH
ARE BEING ENHANCED BY WEAK EMBEDDED SHORTWAVES MOVING THROUGH THE
FLOW ALOFT. COULD SEE A FEW STRONGER STORMS DEVELOP THROUGH THE
AFTERNOON HOURS AS THE AIRMASS DESTABILIZES IN THE PRESENCE OF
STRONG LOW LEVEL SHEAR. HRRR IS FORECASTING MLCAPE AROUND
1000-1500J/KG AND LI`S AROUND -4C WITH 40-50 KT 0-6KM SHEAR AND
0-1KM HELICITY AROUND 200-300 M2/S2 THIS AFTERNOON WITH HIGHEST
VALUES WEST OF HIGHWAY 17. SPC HAS MOST OF THE REGION OUTLOOKED
FOR A MARGINAL RISK OF SEVERE THUNDERSTORMS WITH DAMAGING WIND
GUSTS AND AN ISOLATED TORNADO THE PRIMARY THREAT. PERIODS OF HEAVY
RAINFALL WITH LOCALIZED FLOODING OF POOR DRAINAGE AND LOW LYING
AREA WILL ALSO BE POSSIBLE. EXPECT GUSTY SLY WINDS TO DEVELOP LATE
MORNING THROUGH THE AFTERNOON IN THE WAKE OF THE TROUGH LIFTING
ACROSS THE REGION WHICH COULD BRING GUSTS AROUND 20-30 MPH. TEMPS
WILL BE ALMOST 20 DEGREES ABOVE NORMAL WITH HIGHS EXPECTED IN THE
MID 70S.
&&
.SHORT TERM /TONIGHT/...
AS OF 3 AM WEDNESDAY....LITTLE CHANGE IN THE PATTERN TONIGHT WITH
MOIST SW FLOW CONTINUING. A FEW STRONGER STORMS WILL BE POSSIBLE
EARLY IN THE EVENING BUT GENERALLY EXPECT A DECREASE IN COVERAGE
THROUGH THE OVERNIGHT AS SHORTWAVE ENERGY LIFTS NORTH OF THE
REGION AND THE UPPER RIDGE OVER THE WESTERN ATLANTIC BEGINS TO
BUILDS WEST SOME. WILL CONTINUE A DECREASING TREND IN POPS THROUGH
THE OVERNIGHT. MODERATE SLY WINDS WILL BRING VERY MILD OVERNIGHT
TEMPS IN THE UPPER 60S TO 70...WHICH IS ABOUT 30-35 DEGREES ABOVE
NORMAL AND WILL LIKELY BREAK RECORD HIGH MINIMUM TEMPERATURES FOR
THE DAY...SEE CLIMATE SECTION BELOW.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
AS OF 220 AM WED...BIG STORY WILL BE RECORD BREAKING WARM TEMPS
THROUGH MUCH OF THE PERIOD AS STRONG UPPER RIDGE OVER THE ATLANTIC
BUILDS WEST TOWARD THE COAST INTO THE WEEKEND.
THURSDAY THROUGH CHRISTMAS DAY...COVERAGE OF PRECIPITATION WILL
DROP A BIT FOR THURSDAY AND FRIDAY AS UPR RDG GRAD BUILDS W. FCST
SOUNDINGS FOR THU SHOW SBCAPE VALUES POSSIBLY GREATER THAN 1500
J/KG AND LI`S IN THE -3 TO -5 RANGE DURING THE AFTERNOON ALONG
WITH DECENT SHEAR...HOWEVER LACK OF FORCING MAY LIMIT TSRA
POTENTIAL. A FEW STRONG TO POSS SEVERE STORMS CAN NOT BE RULED
OUT GIVEN THE VERY HIGH INSTAB FOR LATE DEC. LOW LVL
THICKNESS/850 TEMPS PEAK THU AFTN WITH SOME HIGHS TEMPS IN THE
LOWER 80S POSS WHICH WILL LIKELY BREAK NUMEROUS RECORDS AND POSS
SET ALL TIME DEC RECORDS. ON FRI UPR RDG BUILDS CLOSER WHICH WILL
ACT TO SUPPRESS CONVECTION AND WITH MORE SUN TEMPS WILL AGAIN BE
VERY WARM REACHING AROUND 80 AGAIN WARMER SPOTS.
SATURDAY THROUGH SUNDAY...STRONG UPPER LEVEL RIDGE HOLDS ACROSS
THE SOUTHEASTERN UNITED STATES THROUGH THE WEEKEND AS LOW
PRESSURE MOVES FROM THE MISSISSIPPI VALLEY INTO THE GREAT LAKES
REGION. THIS WILL KEEP UNSEASONABLY WARM TEMPERATURES IN PLACE
WITH DAYTIME HIGHS WELL INTO THE 70S SATURDAY AND SUNDAY WITH LOWS
IN THE 60S. THERE WILL BE ONLY A SMALL CHANCE OF SHOWERS EACH DAY
GIVEN THE CONTINUED RATHER MOIST AIRMASS WITH FORECAST
PRECIPITABLE WATER VALUES AOA 1.50 INCHES.
MONDAY THROUGH TUESDAY...UPR RDG WILL BEGIN TO SHIFT BACK E WITH
MDLS SHOWING BACKDOOR FRONT DROPPING INTO THE REGION MON THEN
LIFTING BACK N TUE AHEAD OF STRONGER APPROACHING FRONT. CONT PREV
FCST OF CHC POPS EARLY NEXT WEEK WITH STILL VERY MILD TEMPS IN THE
60S TO LOWER 70S...POSS SOME MID 70S TUE.
&&
.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
SHORT TERM /THROUGH TONIGHT/...
AS OF 1020 AM WEDNESDAY...NUMEROUS TO WIDESPREAD SHOWERS ACROSS
THE TERMINALS WHICH MAY BRIEFLY REDUCE VSBYS/CEILINGS INTO THE
AFTERNOON. VFR EXPECTED TO BECOME DOMINANT BY 16/17Z, OUTSIDE OF
HEAVIER SHOWERS. MOIST SW FLOW WILL CONTINUE TO BRING PERIODS OF
SHOWERS ACROSS THE REGION THROUGH THE TAF PERIOD. SOME STORMS
COULD BE STRONG TO MARGINALLY SEVERE TODAY IF INSTABILITY CAN BE
REALIZED WITH STRONG SHEAR IN PLACE AND SHORTWAVE ENERGY MOVING
ACROSS THE REGION. ISOLATED STORMS COULD BRING DAMAGING WIND GUSTS
OR AND WEAK TORNADO. STRONG S WINDS ALSO EXPECTED TO DEVELOP LATE
THIS MORNING THROUGH THE AFTERNOON WITH GUSTS AROUND 20-25 KT
LIKELY. SUB-VFR CONDITIONS POSSIBLE IN STRATUS TONIGHT, ESPECIALLY
INLAND, AS THE BOUNDARY LAYER REMAINS NEAR SATURATION BUT MODERATE
SLY FLOW AROUND 10 KT CONTINUES OVERNIGHT AND THINK VSBYS BELOW
2SM AS SUGGESTED IN SOME OF THE MOS GUIDANCE IS OVERLY
PESSIMISTIC.
LONG TERM /THU THROUGH SATURDAY/...
AS OF 220 AM WED...COVERAGE OF SHRA/TSRA WILL BE LESS THURSDAY
THROUGH SAT BUT WITH LOW LEVELS REMAINING VERY MOIST BOUTS OF SUB
VFR STRATUS AND FOG WILL BE LIKELY LATE NIGHT/EARLY MORN. MAINLY
VFR LATE MORN THRU EVENING HOURS WITH ONLY SMALL CHC OF SHRA/TSRA
CROSSING. ISOLATED STRONG THUNDERSTORMS WILL BE POSS THU.
&&
.MARINE...
SHORT TERM /THROUGH TONIGHT/
AS OF 1025 AM WEDNESDAY...LATEST SURFACE AND BUOY DATA INDICATE SE
TO SSW WINDS ACROSS THE EASTERN NC WATERS 5-15 KT WITH GUSTS NEAR
20 KT FOR THE OUTER BUOYS 41025/41064. THE SURFACE RIDGE REMAINS
CENTERED OFF THE SOUTHEAST COAST THROUGH THE SHORT TERM. A COASTAL
TROUGH JUST SOUTH OF THE WATERS IS PROGGED TO LIFT ACROSS THE
REGION THIS MORNING. SE WINDS AROUND 5-15 KT WILL BECOME SLY AND
INCREASE TO 15-25 KT WITH HIGHER GUSTS AFTER THE TROUGH LIFTS
ACROSS THE REGION AND CONTINUE THROUGH MUCH OF THE OVERNIGHT. SEAS
CURRENTLY AROUND 3-6 FT WILL BUILD IN RESPONSE TO THE STRONGER SLY
FLOW THROUGH THE DAY...PEAKING AROUND 6-10 FT TONIGHT. STRONGEST
WINDS/SEAS WILL OCCUR OVER THE COASTAL WATERS AND WILL CONTINUE
THE SCA. THE SOUNDS AND RIVERS EXPECTED TO REMAIN JUST BELOW
ADVISORY CRITERIA BUT MAY BE CLOSE ACROSS THE PAMLICO SOUND,
ESPECIALLY IN GUSTS.
LONG TERM /THU THROUGH SATURDAY/...
AS OF 220 AM WED...SSW WINDS 15 TO 25 KTS WILL CONT THU BETWEEN
HIGH PRESSURE NEAR BERMUDA AND LOW PRESSURE LIFTING NORTHEAST OF
THE GREAT LAKES. SW WINDS WILL GRAD SUBSIDE THU NIGHT AND FRI AS
WEAK FRONT STALLS TO THE NORTH. THE FRONT WILL LIFT BACK N SAT
WITH CONT LIGHT S TO SW FLOW. SEAS WILL REMAIN ELEVATED THU AND
THU NIGH WITH SCA CONT COASTAL WATERS. SEAS WILL PEAK AT AROUND 8
FT OUTER SRN/CNTRL WATERS THU. SEAS WILL SUBSIDE THU NIGHT AND
FRI WITH SCA ENDING NRN WATERS LATE THU NIGHT AND REST OF WATERS
BY MID DAY FRI. SEAS WILL CONT IN THE 3 TO 5 FT RANGE THRU SAT.
&&
.CLIMATE...
EXTREMELY WARM AND HUMID WEATHER FOR DECEMBER WILL DOMINATE THE
REMAINDER OF CHRISTMAS WEEK. THE FOLLOWING ARE RECORD HIGH MAX
TEMPS, AS WELL AS RECORD HIGH MIN TEMPS, FOR 12/23 THROUGH 12/25,
WHEN THE WARMEST TEMPS ARE EXPECTED. ALSO INCLUDED ARE THE ALL-
TIME HIGHS FOR DECEMBER.
RECORD HIGH MAX TEMPS FOR 12/23 WEDNESDAY
LOCATION TEMP/YEAR
NEW BERN 79/2013 (KEWN ASOS)
CAPE HATTERAS 75/1990 (KHSE ASOS)
GREENVILLE 79/1967 (COOP NOT KPGV AWOS)
MOREHEAD CITY 74/1990 (COOP NOT KMRH ASOS)
KINSTON 82/2013 (COOP NOT KISO AWOS)
JACKSONVILLE 82/1981 (KNCA AWOS)
RECORD HIGH MIN TEMPS FOR 12/23 WEDNESDAY
LOCATION TEMP/YEAR
NEW BERN 63/1990 (KEWN ASOS)
CAPE HATTERAS 66/1990 (KHSE ASOS)
GREENVILLE 61/1990 (COOP - NOT KPGV AWOS)
MOREHEAD CITY 64/2013 (COOP - NOT KMRH ASOS)
KINSTON 65/2013 (COOP- NOT KISO AWOS)
JACKSONVILLE 63/1956 (KNCA AWOS)
RECORD HIGH MAX TEMPS F0R 12/24 THURSDAY
LOCATION TEMP/YEAR
NEW BERN 76/1964 (KEWN ASOS)
CAPE HATTERAS 72/1990 (KHSE ASOS)
GREENVILLE 73/1988 (COOP NOT KPGV AWOS)
MOREHEAD CITY 72/1990 (COOP NOT KMRH ASOS)
KINSTON 78/2013 (COOP NOT KISO AWOS)
JACKSONVILLE 74/1990 (KNCA AWOS)
RECORD HIGH MIN TEMPS FOR 12/24 THURSDAY
LOCATION TEMP/YEAR
NEW BERN 55/2014 (KEWN ASOS)
CAPE HATTERAS 62/1986 (KHSE ASOS)
GREENVILLE 56/1956 (COOP - NOT KPGV AWOS)
MOREHEAD CITY 60/1956 (COOP - NOT KMRH ASOS)
KINSTON 63/1990 (COOP- NOT KISO AWOS)
JACKSONVILLE 54/2014 (KNCA AWOS)
RECORD HIGH MAX TEMPS FOR 12/25 FRIDAY
LOCATION TEMP/YEAR
NEW BERN 78/1955 (KEWN ASOS)
CAPE HATTERAS 73/1964 (KHSE ASOS)
GREENVILLE 77/1964 (COOP NOT KPGV AWOS)
MOREHEAD CITY 74/1974 (COOP NOT KMRH ASOS)
KINSTON 78/1932 (COOP NOT KISO AWOS)
JACKSONVILLE 76/1974 (KNCA AWOS)
RECORD HIGH MIN TEMPS FOR 12/25 FRIDAY
LOCATION TEMP/YEAR
NEW BERN 63/1964 (KEWN ASOS)
CAPE HATTERAS 61/1964 (KHSE ASOS)
GREENVILLE 59/1964 (COOP - NOT KPGV AWOS)
MOREHEAD CITY 60/2008 (COOP - NOT KMRH ASOS)
KINSTON 61/1932 (COOP- NOT KISO AWOS)
JACKSONVILLE 61/1987 (KNCA AWOS)
**ALL-TIME RECORD HIGH TEMPS FOR DECEMBER**
LOCATION TEMP/YEAR
NEW BERN 83/1971 (KEWN ASOS)
CAPE HATTERAS 78/1991 (KHSE ASOS)
GREENVILLE 82/1998 (COOP - NOT KPGV AWOS)
MOREHEAD CITY 79/1998 (COOP - NOT KMRH ASOS)
KINSTON 87/1918 (COOP - NOT KISO AWOS)
JACKSONVILLE 82/1998 (KNCA AWOS)
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL NOON EST FRIDAY FOR AMZ152-154-156-
158.
SMALL CRAFT ADVISORY UNTIL 3 AM EST FRIDAY FOR AMZ150.
&&
$$
SYNOPSIS...SK
NEAR TERM...SK/DAG
SHORT TERM...SK
LONG TERM...RF/DAG
AVIATION...RF/SK
MARINE...RF/SK/DAG
CLIMATE...MHX
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
732 AM EST WED DEC 23 2015
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE OFFSHORE THROUGH THE WEEKEND. A WEAK
COLD FRONT WILL APPROACH FROM THE NORTH THURSDAY NIGHT THEN STALL
NEAR THE VIRGINIA BORDER FRIDAY. THE FRONT WILL LIFT BACK NORTH
OVER THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 7 AM WEDNESDAY...UPDATE INCREASES POPS FOLLOWING RADAR
TRENDS. AREA OF STRONGER SHOWERS AND THUNDERSTORMS ACROSS SE NC
WITH IR SATELLITE SHOWING COOLING CLOUD TOPS WILL BE WATCHED
CLOSELY AS IT IS PROGGED TO MOVE ACROSS THE COASTAL PLAIN THROUGH
MORNING...WHICH WILL BRING A PERIOD OF HEAVY RAIN AND POSSIBLY
GUSTY WINDS. ALSO UPDATED T/TD TRENDS WHICH HAVE BEEN INCREASING
A FEW DEGREES OVER THE PAST SEVERAL HOURS MOST LOCATIONS.
PREVIOUS DISCUSSION...AN UPPER TROUGH MOVING INTO THE PLAINS WITH
RIDGING OVER THE ATLANTIC IS BRINGING DEEP SW FLOW ACROSS THE
EASTERN CONUS THAT IS TAPPING INTO TROPICAL PACIFIC MOISTURE
BRINGING PWATS AROUND 1.75 INCHES WHICH IS AT OR ABOVE
CLIMATOLOGICAL MAXIMUM FOR LATE DECEMBER. SFC HIGH PRES REMAINS
CENTERED OFFSHORE WITH A COASTAL TROUGH JUST SOUTH OF THE REGION
PROGGED TO LIFT ACROSS THE REGION TODAY. THIS PATTERN WILL
CONTINUE TO BRING PERIODS OF SHOWERS ACROSS THE REGION TODAY WHICH
ARE BEING ENHANCED BY WEAK EMBEDDED SHORTWAVES MOVING THROUGH THE
FLOW ALOFT. COULD SEE A FEW STRONGER STORMS DEVELOP THROUGH THE
AFTERNOON HOURS AS THE AIRMASS DESTABILIZES IN THE PRESENCE OF
STRONG LOW LEVEL SHEAR. HRRR IS FORECASTING MLCAPE AROUND
1000-1500J/KG AND LI`S AROUND -4C WITH 40-50 KT 0-6KM SHEAR AND
0-1KM HELICITY AROUND 200-300 M2/S2 THIS AFTERNOON WITH HIGHEST
VALUES WEST OF HIGHWAY 17. SPC HAS MOST OF THE REGION OUTLOOKED
FOR A MARGINAL RISK OF SEVERE THUNDERSTORMS WITH DAMAGING WIND
GUSTS AND AN ISOLATED TORNADO THE PRIMARY THREAT. PERIODS OF HEAVY
RAINFALL WITH LOCALIZED FLOODING OF POOR DRAINAGE AND LOW LYING
AREA WILL ALSO BE POSSIBLE. EXPECT GUSTY SLY WINDS TO DEVELOP LATE
MORNING THROUGH THE AFTERNOON IN THE WAKE OF THE TROUGH LIFTING
ACROSS THE REGION WHICH COULD BRING GUSTS AROUND 20-30 MPH. TEMPS
WILL BE ALMOST 20 DEGREES ABOVE NORMAL WITH HIGHS EXPECTED IN THE
MID 70S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/...
AS OF 3 AM WEDNESDAY....LITTLE CHANGE IN THE PATTERN TONIGHT WITH
MOIST SW FLOW CONTINUING. A FEW STRONGER STORMS WILL BE POSSIBLE
EARLY IN THE EVENING BUT GENERALLY EXPECT A DECREASE IN COVERAGE
THROUGH THE OVERNIGHT AS SHORTWAVE ENERGY LIFTS NORTH OF THE
REGION AND THE UPPER RIDGE OVER THE WESTERN ATLANTIC BEGINS TO
BUILDS WEST SOME. WILL CONTINUE A DECREASING TREND IN POPS THROUGH
THE OVERNIGHT. MODERATE SLY WINDS WILL BRING VERY MILD OVERNIGHT
TEMPS IN THE UPPER 60S TO 70...WHICH IS ABOUT 30-35 DEGREES ABOVE
NORMAL AND WILL LIKELY BREAK RECORD HIGH MINIMUM TEMPERATURES FOR
THE DAY...SEE CLIMATE SECTION BELOW.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
AS OF 220 AM WED...BIG STORY WILL BE RECORD BREAKING WARM TEMPS
THROUGH MUCH OF THE PERIOD AS STRONG UPPER RIDGE OVER THE ATLANTIC
BUILDS WEST TOWARD THE COAST INTO THE WEEKEND.
THURSDAY THROUGH CHRISTMAS DAY...COVERAGE OF PRECIPITATION WILL
DROP A BIT FOR THURSDAY AND FRIDAY AS UPR RDG GRAD BUILDS W. FCST
SOUNDINGS FOR THU SHOW SBCAPE VALUES POSSIBLY GREATER THAN 1500
J/KG AND LI`S IN THE -3 TO -5 RANGE DURING THE AFTERNOON ALONG
WITH DECENT SHEAR...HOWEVER LACK OF FORCING MAY LIMIT TSRA
POTENTIAL. A FEW STRONG TO POSS SEVERE STORMS CAN NOT BE RULED
OUT GIVEN THE VERY HIGH INSTAB FOR LATE DEC. LOW LVL
THICKNESS/850 TEMPS PEAK THU AFTN WITH SOME HIGHS TEMPS IN THE
LOWER 80S POSS WHICH WILL LIKELY BREAK NUMEROUS RECORDS AND POSS
SET ALL TIME DEC RECORDS. ON FRI UPR RDG BUILDS CLOSER WHICH WILL
ACT TO SUPPRESS CONVECTION AND WITH MORE SUN TEMPS WILL AGAIN BE
VERY WARM REACHING AROUND 80 AGAIN WARMER SPOTS.
SATURDAY THROUGH SUNDAY...STRONG UPPER LEVEL RIDGE HOLDS ACROSS
THE SOUTHEASTERN UNITED STATES THROUGH THE WEEKEND AS LOW
PRESSURE MOVES FROM THE MISSISSIPPI VALLEY INTO THE GREAT LAKES
REGION. THIS WILL KEEP UNSEASONABLY WARM TEMPERATURES IN PLACE
WITH DAYTIME HIGHS WELL INTO THE 70S SATURDAY AND SUNDAY WITH LOWS
IN THE 60S. THERE WILL BE ONLY A SMALL CHANCE OF SHOWERS EACH DAY
GIVEN THE CONTINUED RATHER MOIST AIRMASS WITH FORECAST
PRECIPITABLE WATER VALUES AOA 1.50 INCHES.
MONDAY THROUGH TUESDAY...UPR RDG WILL BEGIN TO SHIFT BACK E WITH
MDLS SHOWING BACKDOOR FRONT DROPPING INTO THE REGION MON THEN
LIFTING BACK N TUE AHEAD OF STRONGER APPROACHING FRONT. CONT PREV
FCST OF CHC POPS EARLY NEXT WEEK WITH STILL VERY MILD TEMPS IN THE
60S TO LOWER 70S...POSS SOME MID 70S TUE.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
SHORT TERM /THROUGH TONIGHT/...
AS OF 7 AM WEDNESDAY...AREAS OF FOG/ST CONTINUES ACROSS THE
COASTAL PLAIN THIS MORNING BRINGING IFR/LIFR CONDITIONS ALONG WITH
NUMEROUS TO WIDESPREADS SHOWERS ACROSS RTES. CONDITIONS EXPECTED
TO ONLY GRADUALLY IMPROVE THIS MORNING WITH VFR EXPECTED TO BECOME
DOMINANT AROUND 15Z...OUTSIDE OF HEAVIER SHOWERS. MOIST SW FLOW
WILL CONTINUE TO BRING PERIODS OF SHOWERS ACROSS THE REGION
THROUGH THE TAF PERIOD. SOME STORMS COULD BE STRONG TO MARGINALLY
SEVERE TODAY IF INSTABILITY CAN BE REALIZED WITH STRONG SHEAR IN
PLACE AND SHORTWAVE ENERGY MOVING ACROSS THE REGION. ISOLATED
STORMS COULD BRING DAMAGING WIND GUSTS OR AND WEAK TORNADO. STRONG
S WINDS ALSO EXPECTED TO DEVELOP LATE THIS MORNING THROUGH THE
AFTERNOON WITH GUSTS AROUND 20-25 KT LIKELY. SUB-VFR CONDITIONS
POSSIBLE IN STRATUS TONIGHT...ESPECIALLY INLAND...AS THE BOUNDARY
LAYER REMAINS NEAR SATURATION BUT MODERATE SLY FLOW AROUND 10 KT
CONTINUES OVERNIGHT AND THINK VSBYS BELOW 2SM AS SUGGESTED IN
SOME OF THE MOS GUIDANCE IS OVERLY PESSIMISTIC.
LONG TERM /THU THROUGH SATURDAY/...
AS OF 220 AM WED...COVERAGE OF SHRA/TSRA WILL BE LESS THURSDAY
THROUGH SAT BUT WITH LOW LEVELS REMAINING VERY MOIST BOUTS OF SUB
VFR STRATUS AND FOG WILL BE LIKELY LATE NIGHT/EARLY MORN. MAINLY
VFR LATE MORN THRU EVENING HOURS WITH ONLY SMALL CHC OF SHRA/TSRA
CROSSING. ISOLATED STRONG THUNDERSTORMS WILL BE POSS THU.
&&
.MARINE...
SHORT TERM /THROUGH TONIGHT/
AS OF 3 AM WEDNESDAY...SFC HIGH PRES REMAINS CENTERED OFF THE
SOUTHEAST COAST THROUGH THE SHORT TERM. A COASTAL TROUGH JUST
SOUTH OF THE WATERS IS PROGGED TO LIFT ACROSS THE REGION THIS
MORNING. SE WINDS AROUND 5-15 KT WILL BECOME SLY AND INCREASE TO
15-25 KT WITH HIGHER GUSTS AFTER THE TROUGH LIFTS ACROSS THE
REGION AND CONTINUE THROUGH MUCH OF THE OVERNIGHT. SEAS CURRENTLY
AROUND 3-6 FT WILL BUILD IN RESPONSE TO THE STRONGER SLY FLOW
THROUGH THE DAY...PEAKING AROUND 6-10 FT TONIGHT. STRONGEST
WINDS/SEAS WILL OCCUR OVER THE COASTAL WATERS AND WILL CONTINUE
THE SCA. THE SOUNDS AND RIVERS EXPECTED TO REMAIN JUST BELOW
ADVISORY CRITERIA...BUT MAY BE CLOSE ACROSS THE PAMLICO
SOUND...ESPECIALLY IN GUSTS.
LONG TERM /THU THROUGH SATURDAY/...
AS OF 220 AM WED...SSW WINDS 15 TO 25 KTS WILL CONT THU BETWEEN
HIGH PRESSURE NEAR BERMUDA AND LOW PRESSURE LIFTING NORTHEAST OF
THE GREAT LAKES. SW WINDS WILL GRAD SUBSIDE THU NIGHT AND FRI AS
WEAK FRONT STALLS TO THE NORTH. THE FRONT WILL LIFT BACK N SAT
WITH CONT LIGHT S TO SW FLOW. SEAS WILL REMAIN ELEVATED THU AND
THU NIGH WITH SCA CONT CSTL WTRS. SEAS WILL PEAK AT AROUND 8 FT
OUTER SRN/CNTRL WTRS THU. SEAS WILL SUBSIDE THU NIGHT AND FRI WITH
SCA ENDING NRN WTRS LATE THU NIGHT AND REST OF WTRS BY MID DAY
FRI. SEAS WILL CONT IN THE 3 TO 5 FT RANGE THRU SAT.
&&
.CLIMATE...
EXTREMELY WARM AND HUMID WEATHER FOR DECEMBER WILL DOMINATE THE
REMAINDER OF CHRISTMAS WEEK. THE FOLLOWING ARE RECORD HIGH MAX
TEMPS, AS WELL AS RECORD HIGH MIN TEMPS, FOR 12/23 THROUGH 12/25,
WHEN THE WARMEST TEMPS ARE EXPECTED. ALSO INCLUDED ARE THE ALL-
TIME HIGHS FOR DECEMBER.
RECORD HIGH MAX TEMPS FOR 12/23 WEDNESDAY
LOCATION TEMP/YEAR
NEW BERN 79/2013 (KEWN ASOS)
CAPE HATTERAS 75/1990 (KHSE ASOS)
GREENVILLE 79/1967 (COOP NOT KPGV AWOS)
MOREHEAD CITY 74/1990 (COOP NOT KMRH ASOS)
KINSTON 82/2013 (COOP NOT KISO AWOS)
JACKSONVILLE 82/1981 (KNCA AWOS)
RECORD HIGH MIN TEMPS FOR 12/23 WEDNESDAY
LOCATION TEMP/YEAR
NEW BERN 63/1990 (KEWN ASOS)
CAPE HATTERAS 66/1990 (KHSE ASOS)
GREENVILLE 61/1990 (COOP - NOT KPGV AWOS)
MOREHEAD CITY 64/2013 (COOP - NOT KMRH ASOS)
KINSTON 65/2013 (COOP- NOT KISO AWOS)
JACKSONVILLE 63/1956 (KNCA AWOS)
RECORD HIGH MAX TEMPS F0R 12/24 THURSDAY
LOCATION TEMP/YEAR
NEW BERN 76/1964 (KEWN ASOS)
CAPE HATTERAS 72/1990 (KHSE ASOS)
GREENVILLE 73/1988 (COOP NOT KPGV AWOS)
MOREHEAD CITY 72/1990 (COOP NOT KMRH ASOS)
KINSTON 78/2013 (COOP NOT KISO AWOS)
JACKSONVILLE 74/1990 (KNCA AWOS)
RECORD HIGH MIN TEMPS FOR 12/24 THURSDAY
LOCATION TEMP/YEAR
NEW BERN 55/2014 (KEWN ASOS)
CAPE HATTERAS 62/1986 (KHSE ASOS)
GREENVILLE 56/1956 (COOP - NOT KPGV AWOS)
MOREHEAD CITY 60/1956 (COOP - NOT KMRH ASOS)
KINSTON 63/1990 (COOP- NOT KISO AWOS)
JACKSONVILLE 54/2014 (KNCA AWOS)
RECORD HIGH MAX TEMPS FOR 12/25 FRIDAY
LOCATION TEMP/YEAR
NEW BERN 78/1955 (KEWN ASOS)
CAPE HATTERAS 73/1964 (KHSE ASOS)
GREENVILLE 77/1964 (COOP NOT KPGV AWOS)
MOREHEAD CITY 74/1974 (COOP NOT KMRH ASOS)
KINSTON 78/1932 (COOP NOT KISO AWOS)
JACKSONVILLE 76/1974 (KNCA AWOS)
RECORD HIGH MIN TEMPS FOR 12/25 FRIDAY
LOCATION TEMP/YEAR
NEW BERN 63/1964 (KEWN ASOS)
CAPE HATTERAS 61/1964 (KHSE ASOS)
GREENVILLE 59/1964 (COOP - NOT KPGV AWOS)
MOREHEAD CITY 60/2008 (COOP - NOT KMRH ASOS)
KINSTON 61/1932 (COOP- NOT KISO AWOS)
JACKSONVILLE 61/1987 (KNCA AWOS)
**ALL-TIME RECORD HIGH TEMPS FOR DECEMBER**
LOCATION TEMP/YEAR
NEW BERN 83/1971 (KEWN ASOS)
CAPE HATTERAS 78/1991 (KHSE ASOS)
GREENVILLE 82/1998 (COOP - NOT KPGV AWOS)
MOREHEAD CITY 79/1998 (COOP - NOT KMRH ASOS)
KINSTON 87/1918 (COOP - NOT KISO AWOS)
JACKSONVILLE 82/1998 (KNCA AWOS)
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL NOON EST FRIDAY FOR AMZ152-154-156-
158.
SMALL CRAFT ADVISORY UNTIL 3 AM EST FRIDAY FOR AMZ150.
&&
$$
SYNOPSIS...SK
NEAR TERM...SK
SHORT TERM...SK
LONG TERM...RF/DAG
AVIATION...RF/SK
MARINE...RF/SK
CLIMATE...MHX
AREA FORECAST DISCUSSION
NWS RALEIGH NC
720 AM EST WED DEC 23 2015
.SYNOPSIS...A WEDGE FRONT WILL REMAIN QUASI-STATIONARY OVER THE
PIEDMONT EARLY TODAY...THEN BE OVERTAKEN BY A MARITIME WARM FRONT
THAT WILL SURGE ACROSS THE CAROLINAS AND SOUTHEASTERN VIRGINIA THIS
AFTERNOON. ANOMALOUSLY STRONG SUB-TROPICAL HIGH PRESSURE OVER THE
WEST-CENTRAL ATLANTIC OCEAN WILL THEN DIRECT UNSEASONABLY WARM AND
MOIST SOUTHERLY FLOW THROUGHOUT THE SOUTHEASTERN UNITED STATES
THROUGH CHRISTMAS.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 355 AM WEDNESDAY...
...FLASH FLOOD WATCH CONTINUES ACROSS THE WESTERN PIEDMONT...
A SHORTWAVE TROUGH EMBEDDED WITHIN LARGER-SCALE TROUGH SITUATED
ACROSS MUCH OF THE CONUS WILL ADVANCE NEWD FROM THE SRN PLAINS
TOWARDS THE UPPER GREAT LAKES. ACCOMPANYING DEEPENING SFC LOW WILL
FOLLOW SUITE...TRACKING NEWD FROM THE MID-MO VALLEY TO THE UPPER MS
VALLEY BY LATE AFTERNOON. WHILE THESE FEATURES ARE A LITTLE WAYS
FROM HOME...DEEP SOUTHERLY FLOW ON THE EAST SIDE OF THE TROUGH WILL
ADVECT MODIFIED GULF AIR NORTHWARD INTO THE AREA...BRINGING
ANOMALOUS MOIST AND WARM AIR INTO THE AREA. PWATS ARE FORECAST TO
INCREASE TO 1.6-1.9"(4-5 STANDARD DEVIATIONS ABOVE NORMAL)...WHICH
WILL RIVAL MAX DECEMBER VALUES AT KGSO(1.65"-DATING BACK TO
1948)...WHILE TONIGHTS LOW TEMPERATURES WILL STRUGGLE TO DROP OUT OF
THE 70S AT MOST LOCATIONS...AGAIN HAVING A GOOD CHANCE OF MATCHING
THE ALL-TIME WARMEST DECEMBER MINIMUM TEMPERATURE ON RECORD(RDU-
69...FAY-69...GSO-65).
TWO MAIN CONCERNS ARE: 1)PERIODS OF MODERATE TO HEAVY RAINFALL THAT
MAY RESULT IN BOTH FLASHING FLOODING AS WELL AS MINOR FLOODING
ON AREAS RIVERS AND CREEKS AND 2)ISOLATED THREAT OF SEVERE STORMS
LATER TODAY.
FLOOD THREAT: LATEST RADAR TRENDS SHOW AN UPTICK IN CONVECTION
BREAKING OUT ACROSS THE AREA...FUELED BY A STRENGTHENING 50-60KTS
S-SWLY LOW-LEVEL FLOW EAST OF THE AMPLIFYING SYSTEM TO OUR WEST.
MOST RECENT HRRR SIMULATIONS ARE HANDLING THE CONVECTION
BEST...DEPICTING THE HEAVIEST RAINFALL THIS MORNING ALONG AND EAST
OF HIGHWAY 1. THE AFOREMENTIONED HIGH MOISTURE ANOMALIES WILL
SUPPORT THE POTENTIAL FOR 1.5-2.0"/HOUR RAINFALL RATES OVER THESE
AREAS THIS MORNING THAT WOULD LIKELY CAUSE SOME LOCALIZED FLOODING
GIVEN SATURATED SOILS. HAVE ENTERTAINED THE IDEA OF EXPANDING THE
FLOOD WATCH TO INCLUDE COUNTIES ACROSS THE SANDHILLS AND CENTRAL
PIEDMONT...BUT AS PRECIP HAS BECOME MORE CONVECTIVE IN NATURE...ANY
SUCH HEAVY PRECIP WOULD BE FAIRLY LOCALIZED. WITH A SECOND ROUND OF
SHOWERS AND POSSIBLY A FEW STRONG TO SEVERE STORMS EXPECTED LATER
THIS AFTERNOON AS WARM SECTOR BECOMES ESTABLISHED OVER THE
AREA...AREAS IN THE WATCH COULD STILL SEE LOCALIZED HEAVY AMOUNTS OF
ONE TO TWO INCHES. AS SUCH... WILL KEEP THE FLASH FLOOD WATCH
CONFINED TO THE WESTERN PIEDMONT.
SEVERE THREAT: AS TEMPS CLIMB INTO THE LOWER TO MID 70S AND SFC
DEWPOINTS APPROACH UPPER 60S TO NEAR 70...MODELS SHOW 500-1000 J/KG
OF MUCAPE(HIGHEST IN THE EAST)DEVELOPING OVER THE AREA. 40-50KT DEEP
SHEAR AND SHERBE VALUES APPROACHING 1.0 COULD SUPPORT A FEW STRONG
TO SVR WIND GUSTS AND POSSIBLY AN ISOLATED TORNADO. WILL CONTINUE TO
ADVERTISE SEVERE POTENTIAL ACROSS THE EASTERN HALF OF THE FORECAST
AREA IN THE HWO.
&&
.SHORT TERM /THURSDAY AND THURSDAY NIGHT/...
AS OF 355 AM WEDNESDAY...
ON THE WESTERN PERIPHERY OF ANOMALOUSLY STRONG SUB-TROPICAL RIDGING
CENTERED OVER THE WEST-CENTRAL ATLANTIC...SHORTWAVE RIDGING AND
ASSOCIATED HEIGHT RISES ALOFT WILL BUILD BEHIND THE MAIN SHORTWAVE
TROUGH LIFTING INTO EASTERN CANADA. WITH RIDGING ALOFT AND AN
ASSOCIATED PROBABLE CAPPING INVERSION DEPICTED ON NAM BUFR
SOUNDINGS...THE DAY WILL LIKELY BE A DRY ONE...THOUGH DIURNAL
HEATING OF THE UNSEASONABLY WARM (70S TO AROUND 80 IN IN THE I-95
CORRIDOR) AND HUMID BOUNDARY LAYER MAY ALLOW FOR SOME CU TO BYPASS
THE CAP AND GROW INTO ISOLATED SHOWERS/STORMS. IN ADDITION...AN
UPSTREAM QLCS...IN A REGION OF RESIDUALLY STRONG H85 MOISTURE
TRANSPORT DIRECTED INTO THE TN VALLEY...MAY SUPPORT THE EASTWARD
PROGRESSION OF A WEAKENING LONE OF SHOWERS AND STORMS TO CROSS THE
APPALACHIANS AND DRIFT INTO WESTERN NC...INCLUDING THE WESTERN
PIEDMONT EARLY THU NIGHT. INCREASING CINH WITH NOCTURNAL "COOLING"
INTO THE 60S FAVORS A DRY NIGHT OTHERWISE AND ELSEWHERE.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 410 AM WEDNESDAY...
THE STRONG SUB-TROPICAL RIDGE...WITH ANOMALOUSLY HIGH HEIGHTS AND
PRECIPITABLE WATER VALUES BETWEEN 200-300 PERCENT OF NORMAL FROM THE
SOUTHEASTERN UNITED STATES TO EAST-CENTRAL CANADA...WILL MAINTAIN A
VERY MILD-WARM REGIME ACROSS THE SOUTHEASTERN STATES THROUGHOUT THE
PERIOD...AND A WET ONE PRIMARILY NORTHWEST OF CENTRAL NC...AT LEAST
UNTIL LATE IN THE PERIOD. THE MAIN FORECAST UNCERTAINTY REMAINS THE
POSITIONING OF A WAVY FRONTAL ZONE FORECAST TO MEANDER ACROSS THE
MIDDLE ATLANTIC STATES...AND CONSEQUENTLY HOW MUCH SUPPRESSION OF
THE WARMTH OCCURS EAST OF THE APPALACHIANS...DICTATED BY A BATTLE
BETWEEN THE SUB-TROPICAL RIDGE AND CONFLUENT SPLIT FLOW
ALOFT/UNDERLYING POLAR HIGHS FORECAST TO DEVELOP ACROSS THE GREAT
LAKES AND NEW ENGLAND BY THIS WEEKEND.
THE TIMING OF POTENTIAL COLD FRONTAL SURGES INTO NC...IF THEY
OCCUR...ARE FAVORED LATE FRI NIGHT-SAT...AND AGAIN SUN NIGHT-
MON...WITH THE FORMER APPEARING INCREASINGLY UNLIKELY TO AFFECT
CENTRAL NC. OTHERWISE UNSEASONABLY MILD-WARM AND HUMID CONDITIONS IN
DEEP SOUTHERLY FLOW AROUND THE SUB-TROPICAL RIDGE WILL PREVAIL. THE
PRIMARY BRANCH OF THE NORTHERN STREAM WILL BE BLOCKED TO THE NW BY
THE SUB-TROPICAL RIDGING...SO FORCING FOR ASCENT AND ASSOCIATED
PRECIPITATION CHANCES WILL REMAIN LOW (GENERALLY AOB 20 PERCENT) AND
INSTEAD DRIVEN BY LOWER AMPLITUDE SOUTHERN STREAM PERTURBATIONS AND
ASSOCIATED SURGES OF LOW LEVEL THETA-E ADVECTION AND BRIEF EROSION
OF A CAPPING INVERSION FRI-SAT...WITH SAID CAPPING MORE LIKELY TO BE
OVERCOME BY DIURNAL HEATING IN AN AIRMASS MORE CHARACTERISTIC OF
APRIL-MAY THAN LATE DECEMBER.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
AS OF 720 AM WEDNESDAY...
24 HOUR TAF PERIOD: WIDESPREAD ADVERSE AVIATION CONDITIONS WILL
PERSIST THROUGH THE 24 HOUR TAF PERIOD AS AN ANOMALOUSLY MOIST AND
WARM AIRMASS ADVECTS INTO THE AREA.
CEILINGS HAVE IMPROVED TO MVFR AND EVEN VFR ACROSS CENTRAL AND EASTERN
PORTIONS OF THE FORECAST AS WARM SECTOR OVERTAKES THE AREA FROM THE
SOUTH. HOWEVER WE ARE STILL SEEING SOME IFR AND LIFR VISIBILITY
RESTRICTIONS WITH THE HEAVIER SHOWERS. CONDITIONS WILL BE UP AND
DOWN TODAY...BOUNCING FROM VFR TO IFR WITH SCATTERED TO NUMEROUS
SHOWERS AND STORMS EXPECTED THIS AFTERNOON AND EVENING AS WE
DESTABILIZE.
CONDITIONS WILL BE SLOWER TO IMPROVE AT KINT AND KGSO...PERHAPS
IMPROVING TO MVFR BY THE EARLY AFTERNOON AS THE WARM AIR AND
INCREASING INSTABILITY FINALLY HELP TO SCOUR OUT THE LINGERING
WEDGE AIRMASS.
ADDITIONALLY...SOUTHERLY WINDS WILL INCREASE...GUSTING UP TO 20 TO
25 KTS...STRONGEST IN THE EAST.
CEILINGS SHOULD QUICKLY DETERIORATE TO IFR TO LIFR ACROSS THE AREA THIS
EVENING...THOUGH A STEADY 10 TO 15KT SOUTHERLY BREEZE SHOULD
PRECLUDE WIDESPREAD FOG DEVELOPMENT.
OUTLOOK: A MOIST DEEP SOUTHWESTERLY FLOW DOWNSTREAM OF THE LONG WAVE
TROUGH IN PLACE ACROSS THE CENTRAL CONUS WILL SUPPORT A PROLONGED
PERIOD OF ADVERSE AVIATION CONDITIONS THROUGH MUCH OF THE PERIOD.
SUB-VFR CONDITIONS IN LOW CLOUDS/STRATUS WILL ALSO BE LIKELY EACH
MORNING... ALONG WITH THE TREAT OF SOME SHOWERS EACH DAY.
&&
.CLIMATE...
HERE ARE THE AREA RECORD MAXIMUMS AND HIGH MINIMUMS FOR DECEMBER 24TH
AND 25TH. RECORDS HAVE BEEN KEPT IN THE GREENSBORO AREA SINCE
1903... IN THE RALEIGH AREA SINCE 1887... AND IN THE FAYETTEVILLE
AREA SINCE 1910.
DEC 24: RECORD MAXIMUM HIGH MINIMUM
GREENSBORO 71 (1964) 52 (1904)
RALEIGH 75 (1931) 59 (1891)
FAYETTEVILLE 78 (1931) 66 (1990)
DEC 25: RECORD MAXIMUM HIGH MINIMUM
GREENSBORO 74 (1955) 58 (1932)
RALEIGH 75 (1955) 63 (1932)
FAYETTEVILLE 79 (1932) 68 (1932)
&&
.RAH WATCHES/WARNINGS/ADVISORIES... NONE.
&&
$$
SYNOPSIS...2
NEAR TERM...CBL
SHORT TERM...2
LONG TERM...2
AVIATION...CBL
CLIMATE...HARTFIELD/BLAES
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
641 AM EST WED DEC 23 2015
.SYNOPSIS...
NEAR RECORD WARMTH FOR MOST OF THE UPCOMING WEEK DESPITE SOME
FAIRLY CLOUDY CONDITIONS. HIGH CHANCE FOR SHOWERS AND ISOLATED
THUNDERSTORMS TODAY...WITH COVERAGE BECOMING MORE ISOLATED DURING
THURSDAY. DRY MID LEVEL AIR SHOULD SHUT DOWN SHOWER ACTIVITY
FRIDAY AND OVER THE WEEKEND AS HIGH PRESSURE OFF THE SOUTHEAST
COAST CONTINUES TO RIDGE ACROSS THE AREA.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM WEDNESDAY...LATEST LOCAL AND MOSAIC RADAR DATA
INDICATES PCPN CONTINUES TO STREAM UP TO THE NNE ACROSS THE
CAROLINAS. THIS IS IN RESPONSE TO A MIDLEVEL S/W TROF LIFTING N TO
NE WITHIN STRONG MID-LEVEL SSW FLOW. THE BEST OR MAIN DYNAMICS
FROM THIS S/W TROF STAY WEST OF THE ILM CWA TODAY...BUT MODELS
INDICATE THE TRAILING MID- LEVEL SHEARED AXIS WILL MAKE ITS WAY TO
THE CAROLINA COASTS BY LATE THIS EVENING. DEEP GULF OF MEXICO AND
ATLANTIC MOISTURE WILL CONTINUE TO PUMP ACROSS THE ILM CWA WITH
PROGGED PWS IN THE 1.5 TO 2.00 INCH RANGE. TO PUT IT ALL
TOGETHER...THE FA WILL BE UNDER THE LIKELY TO CATEGORICAL POP
THREAT FROM SHOWERS AND EMBEDDED ISOLATED THUNDERSTORMS TODAY THRU
THIS EVENING. AVBL CAPE OF 1K TO POSSIBLY 1.25K WILL BE LOW
ALTHOUGH BETTER THAN YESTERDAY...AND WITH PROGGED LAPSE RATES
REMAINING SUSPECT...HAVE KEPT THE TSTORM THREAT TO ISOLATED AT
BEST FOR NOW.
NO FLOOD WATCHES ARE FORECAST FOR THE ILM CWA. HOWEVER...ANY
TRAINING OF HEAVY SHOWERS OVER AREAS RECEIVING A GOOD DOSE OF
RAINFALL FROM TUESDAY...COULD RESULT IN PONDING OF WATER
ESPECIALLY ACROSS LOW LYING AREAS AND PRONE ROADWAYS. WILL
HIGHLIGHT THIS IN THE HAZARDOUS WEATHER OUTLOOK.
TEMPS WILL CONTINUE TO RUN 15 TO 25+ DEGREES ABOVE NORMAL.
TODAYS HIGHS IN THE MID TO UPPER 70S AND TONIGHTS LOWS IN THE MID
TO UPPER 60S. THIS SOUNDS MORE LIKE A MID FALL OR MID SPRING TEMP
FORECAST. OF NOTE...NORMAL HIGHS ARE IN THE MID TO UPPER 50S AND
NORMAL LOWS ARE IN LOW TO MID 30S.
&&
.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
AS OF 3 AM WEDNESDAY...PATTERN CONSISTENCY MORE TYPICAL OF THE WARM
SEASON IN PLACE THROUGH THE PERIOD WITH UPPER RIDGE AND BERMUDA HIGH-
LIKE SURFACE LOCKING INTO PLACE. NO SURPRISE THEN THAT THE
ATMOSPHERE WILL BE PRIMED WITH BOTH COPIOUS WARMTH AND MOISTURE. THE
WARMTH WILL MANIFEST ITSELF AS, WELL, WARMTH. NEAR RECORD VALUES, IN
FACT. THE MOISTURE WILL MOSTLY TAKE FORM OF FAIRLY WIDESPREAD CLOUD
COVER BUT ALSO SOME VERY LOW RAIN CHANCES. THESE LOW RAIN CHANCES
WILL BE FOCUSED ALONG WESTERN ZONES ON THURSDAY AS A WEAK VORT
STREAKS BY COINCIDING WITH A RIBBON OF THE DEEPEST MOISTURE. (THE
OFFSHORE QPF POSSIBLY AFFECTING THE COAST DEPICTED ON THE WRF SEEMS
IMPLAUSIBLE GIVEN THE WARM AIR BEING STABILIZED BY THE CHILLY SSTS).
IT MAY THEN SHIFT TO NORTHERN AND WESTERN ZONES AS A COLD FRONT
BACKDOORS ITS WAY TO THE NC/VA BORDER. OVERALL THOUGH FEEL THAT
FRIDAY MOSTLY RAIN-FREE AS THE RIDGE ALOFT BUILDS WESTWARD PUMPING
HEIGHT RISES INTO THE REGION SUPPRESSING WHAT MAY ALSO BE AN ATTEMPT
AT SEA BREEZE AND WEST WALL CONVECTION SHOWN IN SOME MODELS.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 3 AM WEDNESDAY... MODERATELY HIGHLY AMPLIFIED PATTERN IN PLACE
FOR THE ENTIRE PERIOD. STALWART RIDGE ALOFT HOLDS JUST EAST OF THE
BAHAMAS WHILE CUTOFF UPPER LOW EJECTS FROM THE SOUTHWESTERN U.S.
INTO THE OHIO VALLEY SATURDAY THROUGH MONDAY. TEMPERATURES WILL
CONTINUE THEIR IMPRESSIVE DEVIATIONS FROM CLIMATOLOGY WITH DAYTIME
HIGHS NEARLY 20 DEGREES ABOVE NORMAL AND NIGHTTIME DEVIATIONS OFTEN
EVEN LARGER AS CLOUD COVER LINGERS BENEATH THE SUBSIDENCE INVERSION
BORNE OF THE UPPER RIDGE. RAIN CHANCES ARE BOTH TOUGH TO RULE OUT
WITH SO MUCH LOW LEVEL MOISTURE BUT ALSO HARD TO GET EXCITED ABOUT
DUE TO THE UPPER RIDGE. THE EXCEPTION MAY BE MONDAY WHEN THE RIDGE
GETS BEAT DOWN SUFFICIENTLY FOR SOME HEIGHT FALLS LOCALLY. THEN
AGAIN, THIS USUALLY OCCURS MORE SLOWLY THAN PORTRAYED IN GUIDANCE.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
AS OF 12Z...THE HRRR MODEL INITIALIZED REASONABLY WELL AND BRINGS
THE FOCUS OF THE PRECIP TO THE COAST BY LATE MORNING. CEILINGS ARE
A BIT ALL OVER THE PLACE...AS WELL AS THE VISIBILITIES IN THE HEAVIER
PRECIP. CEILINGS TODAY WILL BOUNCE FROM IFR TO VFR WITH VISIBILITIES
BRIEFLY IFR IN THE HEAVIER EMBEDDED CONVECTION. MID AND HIGH LEVEL
MOISTURE WILL CONTINUE THROUGH THE END OF THE FORECAST PERIOD. THE
SOUTHERLY GRADIENT WILL REMAIN TIGHT...WITH GUST TO 20 KTS EXPECTED
AT ANY TIME DURING THE NEXT 24 HOURS. A RUMBLE OF THUNDER CAN NOT
BE RULED OUT.
EXTENDED OUTLOOK...POSSIBLE MVFR TO IFR CONDITIONS IN PCPN AND LOW
CEILINGS FROM THROUGH THURSDAY...OTHERWISE EXPECT VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM WEDNESDAY...SMALL CRAFT ADVISORY CONDITIONS EXPECTED
THRU THIS PERIOD. SFC PRESSURE PATTERN THRU TONIGHT TO YIELD SSE-S
WIND DIRECTIONS THIS MORNING...BECOMING S-SSW BY MIDDAY AND
CONTINUING THRU TONIGHT. A TIGHTENING SFC PG WILL DEVELOP ACROSS
THE LOCAL WATERS EARLY TODAY...AND WILL REMAIN TIGHTENED THRU
TONIGHT. THIS WILL YIELD 10 TO 20 KT SUSTAINED WIND SPEEDS THIS
MORNING THAT COULD OCCASIONALLY REACH 15 TO 25 KT FROM MIDDAY
THROUGH THIS EVENING. IN ADDITION...GUSTS COULD APPROACH 30 KT
ESPECIALLY OVER SSTS THAT ARE WELL INTO THE 60S. LOCAL SSTS HAVE
ALREADY SHOWN AN INCREASE FROM 24 HRS AGO DUE TO THE ONSHORE FLOW
WITH LOW 60S COMMON NOW. EXPECT THIS SLOW INCREASING TREND TO
CONTINUE WITH LOW TO MID 60S BECOMING MORE COMMON BY EARLY THU.
AS A RESULT...SEA FOG DEVELOPMENT SHOULD NOT BE AN ISSUE DURING
THIS TIME PERIOD.
SIGNIFICANT SEAS WILL BUILD TO 4 TO 7 FT TODAY...AND PEAK 5 TO
8 FT LATE THIS AFTN THRU TONIGHT. THE 8 FOOTERS WILL PRIMARILY
OCCUR OVER THE WATERS OFF CAPE FEAR. WIND DRIVEN WAVES AT 6 TO 7
SECOND PERIODS WILL DOMINATE THE SEAS.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 3 AM WEDNESDAY... PERIOD INITIALIZES WITH A SMALL CRAFT
ADVISORY IN A MODERATELY PINCHED SOUTHWESTERLY GRADIENT FLOW WITH
SOME EMBEDDED ENERGY. A SLIGHT WESTWARD EXTENSION OF A RIDGE AXIS
INTO GA/FL ON THE PART OF THE OFFSHORE HIGH LEADS TO A SLIGHT
WEAKENING OF THE GRADIENT LATER THURSDAY INTO THURSDAY NIGHT AND
FRIDAY. WIND REMAINS MOSTLY SOUTHWESTERLY ON FRIDAY BUT IN A
LIGHTENED STATE. THE RIDGE AXIS SHOULD ALSO DISRUPT THE SWELL
ENERGY A BIT TO HELP FURTHER REDUCE DOMINANT WAVE HEIGHT.
LONG TERM /SATURDAY THROUGH SUNDAY/...
AS OF 3 AM WEDNESDAY... MUCH MORE OF A WARM SEASON PATTERN IN PLACE
WITH A WEST ATLANTIC HIGH DOMINATING AND A COMPLETE LACK OF ANY
FRONTS. THE MAIN DIFFERENCE PATTERN-WISE WILL BE THAT THE HIGH WILL
BE WEAKER AND FURTHER WEST THAN WHAT IS NORMALLY OBSERVED IN THE
WARM SEASON. AS SUCH WIND SPEEDS MAY WELL BE CAPPED AT 10KT AS THE
DIRECTION REMAINS SOUTH TO SOUTHWESTERLY. SEAS WILL AVERAGE 2 TO 3
AND OCCASIONALLY (WELL OFFSHORE) 4 FT.
&&
.TIDES/COASTAL FLOODING...
AS OF 630 AM WEDNESDAY...LATEST MODELS INDICATE THE GAGE READING
ALONG THE CAPE FEAR RIVER OF DOWNTOWN WILMINGTON WILL REACH 5.70
FT MLLW AT HIGH TIDE THIS MORNING...WHICH OCCURS AROUND 730 AM.
THIS SURPASSES THE MINOR COASTAL FLOODING THRESHOLD OF 5.50 FT
MLLW. AS A RESULT...A COASTAL FLOOD ADVISORY HAS BEEN ISSUED FOR
LOCATIONS BORDERING ALONG THE LOWER CAPE FEAR RIVER FROM
WILMINGTON SOUTHWARD. LOOK FOR SHALLOW FLOODING TO OCCUR IN A 2
HOUR WINDOW CENTERED AT HIGH TIDE...ROUGHLY BETWEEN 630 AM AND 830
AM.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...COASTAL FLOOD ADVISORY UNTIL 9 AM EST THIS MORNING FOR NCZ107.
MARINE...SMALL CRAFT ADVISORY UNTIL NOON EST THURSDAY FOR AMZ250-252-
254-256-270-274.
&&
$$
SYNOPSIS...DCH
NEAR TERM...DCH
SHORT TERM...MBB
LONG TERM...MBB
AVIATION...HDL
TIDES/COASTAL FLOODING...DCH
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
610 AM EST WED DEC 23 2015
.SYNOPSIS...
NEAR RECORD WARMTH FOR MOST OF THE UPCOMING WEEK DESPITE SOME
FAIRLY CLOUDY CONDITIONS. HIGH CHANCE FOR SHOWERS AND ISOLATED
THUNDERSTORMS TODAY...WITH COVERAGE BECOMING MORE ISOLATED DURING
THURSDAY. DRY MID LEVEL AIR SHOULD SHUT DOWN SHOWER ACTIVITY
FRIDAY AND OVER THE WEEKEND AS HIGH PRESSURE OFF THE SOUTHEAST
COAST CONTINUES TO RIDGE ACROSS THE AREA.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 330 AM WEDNESDAY...LATEST RADAR MOSAIC DATA INDICATES PCPN
CONTINUES TO DEVELOPMENT AND MOVE ACROSS THE CAROLINAS. THIS IS
IN RESPONSE TO A MIDLEVEL S/W TROF LIFTING N TO NE WITHIN STRONG
MID-LEVEL SSW FLOW. THE BEST OR MAIN DYNAMICS FROM THIS S/W TROF
STAY WEST OF THE ILM CWA TODAY...BUT MODELS INDICATE THE TRAILING
MID-LEVEL SHEARED AXIS WILL MAKE ITS WAY TO THE CAROLINA COASTS BY
LATE THIS EVENING. DEEP GULF OF MEXICO AND ATLANTIC MOISTURE WILL
CONTINUE TO PUMP ACROSS THE ILM CWA WITH PROGGED PWS IN THE 1.5 TO
2.00 INCH RANGE. TO PUT IT ALL TOGETHER...THE FA WILL BE UNDER THE
LIKELY TO CATEGORICAL POP THREAT FROM SHOWERS AND EMBEDDED
ISOLATED THUNDERSTORMS TODAY THRU THIS EVENING. AVBL CAPE OF 1K TO
POSSIBLY 1.25K WILL BE LOW ALTHOUGH BETTER THAN YESTERDAY...AND
WITH PROGGED LAPSE RATES REMAINING SUSPECT... HAVE KEPT THE TSTORM
THREAT TO ISOLATED AT BEST FOR NOW.
NO FLOOD WATCHES ARE FORECAST FOR THE ILM CWA. HOWEVER...ANY
TRAINING OF HEAVY SHOWERS OVER AREAS RECEIVING A GOOD DOSE OF
RAINFALL FROM TUESDAY...COULD RESULT IN PONDING OF WATER
ESPECIALLY ACROSS LOW LYING AREAS AND PRONE ROADWAYS. WILL
HIGHLIGHT THIS IN THE HAZARDOUS WEATHER OUTLOOK.
TEMPS WILL CONTINUE TO RUN 15 TO 25+ DEGREES ABOVE NORMAL.
TODAYS HIGHS IN THE MID TO UPPER 70S AND TONIGHTS LOWS IN THE MID
TO UPPER 60S. THIS SOUNDS MORE LIKE A MID FALL OR MID SPRING TEMP
FORECAST. OF NOTE...NORMAL HIGHS ARE IN THE MID TO UPPER 50S AND
NORMAL LOWS ARE IN LOW TO MID 30S.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH THURSDAY NIGHT/...
AS OF 3 AM WEDNESDAY...PATTERN CONSISTENCY MORE TYPICAL OF THE WARM
SEASON IN PLACE THROUGH THE PERIOD WITH UPPER RIDGE AND BERMUDA HIGH-
LIKE SURFACE LOCKING INTO PLACE. NO SURPRISE THEN THAT THE
ATMOSPHERE WILL BE PRIMED WITH BOTH COPIOUS WARMTH AND MOISTURE. THE
WARMTH WILL MANIFEST ITSELF AS, WELL, WARMTH. NEAR RECORD VALUES, IN
FACT. THE MOISTURE WILL MOSTLY TAKE FORM OF FAIRLY WIDESPREAD CLOUD
COVER BUT ALSO SOME VERY LOW RAIN CHANCES. THESE LOW RAIN CHANCES
WILL BE FOCUSED ALONG WESTERN ZONES ON THURSDAY AS A WEAK VORT
STREAKS BY COINCIDING WITH A RIBBON OF THE DEEPEST MOISTURE. (THE
OFFSHORE QPF POSSIBLY AFFECTING THE COAST DEPICTED ON THE WRF SEEMS
IMPLAUSIBLE GIVEN THE WARM AIR BEING STABILIZED BY THE CHILLY SSTS).
IT MAY THEN SHIFT TO NORTHERN AND WESTERN ZONES AS A COLD FRONT
BACKDOORS ITS WAY TO THE NC/VA BORDER. OVERALL THOUGH FEEL THAT
FRIDAY MOSTLY RAIN-FREE AS THE RIDGE ALOFT BUILDS WESTWARD PUMPING
HEIGHT RISES INTO THE REGION SUPPRESSING WHAT MAY ALSO BE AN ATTEMPT
AT SEA BREEZE AND WEST WALL CONVECTION SHOWN IN SOME MODELS.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 3 AM WEDNESDAY... MODERATELY HIGHLY AMPLIFIED PATTERN IN PLACE
FOR THE ENTIRE PERIOD. STALWART RIDGE ALOFT HOLDS JUST EAST OF THE
BAHAMAS WHILE CUTOFF UPPER LOW EJECTS FROM THE SOUTHWESTERN U.S.
INTO THE OHIO VALLEY SATURDAY THROUGH MONDAY. TEMPERATURES WILL
CONTINUE THEIR IMPRESSIVE DEVIATIONS FROM CLIMATOLOGY WITH DAYTIME
HIGHS NEARLY 20 DEGREES ABOVE NORMAL AND NIGHTTIME DEVIATIONS OFTEN
EVEN LARGER AS CLOUD COVER LINGERS BENEATH THE SUBSIDENCE INVERSION
BORNE OF THE UPPER RIDGE. RAIN CHANCES ARE BOTH TOUGH TO RULE OUT
WITH SO MUCH LOW LEVEL MOISTURE BUT ALSO HARD TO GET EXCITED ABOUT
DUE TO THE UPPER RIDGE. THE EXCEPTION MAY BE MONDAY WHEN THE RIDGE
GETS BEAT DOWN SUFFICIENTLY FOR SOME HEIGHT FALLS LOCALLY. THEN
AGAIN, THIS USUALLY OCCURS MORE SLOWLY THAN PORTRAYED IN GUIDANCE.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
AS OF 12Z...THE HRRR MODEL INITIALIZED REASONABLY WELL AND BRINGS
THE FOCUS OF THE PRECIP TO THE COAST BY LATE MORNING. CEILINGS ARE
A BIT ALL OVER THE PLACE...AS WELL AS THE VISIBILITIES IN THE HEAVIER
PRECIP. CEILINGS TODAY WILL BOUNCE FROM IFR TO VFR WITH VISIBILITIES
BRIEFLY IFR IN THE HEAVIER EMBEDDED CONVECTION. MID AND HIGH LEVEL
MOISTURE WILL CONTINUE THROUGH THE END OF THE FORECAST PERIOD. THE
SOUTHERLY GRADIENT WILL REMAIN TIGHT...WITH GUST TO 20 KTS EXPECTED
AT ANY TIME DURING THE NEXT 24 HOURS. A RUMBLE OF THUNDER CAN NOT
BE RULED OUT.
EXTENDED OUTLOOK...POSSIBLE MVFR TO IFR CONDITIONS IN PCPN AND LOW
CEILINGS FROM THROUGH THURSDAY...OTHERWISE EXPECT VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 330 AM WEDNESDAY...SMALL CRAFT ADVISORY CONDITIONS EXPECTED
THRU THIS PERIOD. SFC PRESSURE PATTERN THRU TONIGHT TO YIELD
SSE-S DIRECTIONS THIS MORNING...BECOMING S-SSW BY MIDDAY AND
CONTINUING THRU TONIGHT. A TIGHTENING SFC PG WILL DEVELOP ACROSS
THE LOCAL WATERS TODAY...AND WILL REMAIN TIGHTENED THRU TONIGHT.
THIS WILL YIELD 10 TO 20 KT SUSTAINED WIND SPEEDS THIS MORNING
THAT COULD OCCASIONALLY REACH 15 TO 25 KT FROM MIDDAY THROUGH THIS
EVENING. IN ADDITION...GUSTS COULD APPROACH 30 KT ESPECIALLY OVER
SSTS THAT ARE WELL INTO THE 60S. LOCAL SSTS HAVE ALREADY SHOWN AN
INCREASE FROM 24 HRS AGO DUE TO THE ONSHORE FLOW WITH LOW 60S
COMMON NOW. EXPECT THIS SLOW INCREASING TREND TO CONTINUE WITH LOW
TO MID 60S BECOMING MORE COMMON BY THU. AS A RESULT...SEA FOG
DEVELOPMENT SHOULD NOT BE AN ISSUE DURING THIS TIME PERIOD.
SIGNIFICANT SEAS WILL BUILD TO 4 TO 7 FT TODAY...AND PEAK 5 TO
8 FT LATE THIS AFTN THRU TONIGHT. THE 8 FOOTERS WILL PRIMARILY
OCCUR OVER THE WATERS OFF CAPE FEAR. WIND DRIVEN WAVES AT 6 TO 7
SECOND PERIODS WILL DOMINATE THE SEAS.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 3 AM WEDNESDAY... PERIOD INITIALIZES WITH A SMALL CRAFT
ADVISORY IN A MODERATELY PINCHED SOUTHWESTERLY GRADIENT FLOW WITH
SOME EMBEDDED ENERGY. A SLIGHT WESTWARD EXTENSION OF A RIDGE AXIS
INTO GA/FL ON THE PART OF THE OFFSHORE HIGH LEADS TO A SLIGHT
WEAKENING OF THE GRADIENT LATER THURSDAY INTO THURSDAY NIGHT AND
FRIDAY. WIND REMAINS MOSTLY SOUTHWESTERLY ON FRIDAY BUT IN A
LIGHTENED STATE. THE RIDGE AXIS SHOULD ALSO DISRUPT THE SWELL
ENERGY A BIT TO HELP FURTHER REDUCE DOMINANT WAVE HEIGHT.
LONG TERM /SATURDAY THROUGH SUNDAY/...
AS OF 3 AM WEDNESDAY... MUCH MORE OF A WARM SEASON PATTERN IN PLACE
WITH A WEST ATLANTIC HIGH DOMINATING AND A COMPLETE LACK OF ANY
FRONTS. THE MAIN DIFFERENCE PATTERN-WISE WILL BE THAT THE HIGH WILL
BE WEAKER AND FURTHER WEST THAN WHAT IS NORMALLY OBSERVED IN THE
WARM SEASON. AS SUCH WIND SPEEDS MAY WELL BE CAPPED AT 10KT AS THE
DIRECTION REMAINS SOUTH TO SOUTHWESTERLY. SEAS WILL AVERAGE 2 TO 3
AND OCCASIONALLY (WELL OFFSHORE) 4 FT.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL NOON EST THURSDAY FOR AMZ250-252-
254-256-270-274.
&&
$$
SYNOPSIS...DCH
NEAR TERM...DCH
SHORT TERM...MBB
LONG TERM...MBB
AVIATION...43
MARINE...
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
945 AM CST WED DEC 23 2015
.DISCUSSION...
QUIET FOR NOW...BUT THAT WILL BE CHANGING LATER TODAY.
CURRENTLY...JUST A FEW SCATTERED SHOWERS ACROSS OUR WESTERN AREAS.
MODELS DO ELUDE TOWARD AN ENHANCEMENT IN LIFT AS SOME PVA STARTS
TO ENCROACH ON OUR FAR WESTERN COUNTIES BY 18Z. THUS...AS
INSTABILITIES INCREASE...WE COULD SEE A FEW STRONG STORMS BEGIN TO
DEVELOP WEST OF I-65 AS WE MOVE INTO THE EARLY AFTERNOON. FOR NOW
THOUGH...FOR THE PD PRIOR TO 18Z...WILL GO AHEAD AND LOWER POPS
ACROSS NORTHEASTERN AND EAST CENTRAL AREAS TO JUST A SLIGHT
CHANCE. REMAINDER OF FCST IS IN GOOD SHAPE. THE CONVECTIVE
ACTIVITY...THAT WILL BRING THE SEVERE WEATHER TO OUR AREA THIS
AFTERNOON AND EVENING...IS LOCATED ACROSS CENTRAL AR AT THIS TIME.
A FEW REPORTS OF TSTM WIND DAMAGE HAVE BEEN REPORTED IN ARKANSAS
THIS MORNING.
UPDATE OUT SHORTLY.
&&
.AVIATION...
12Z TAF DISCUSSION.
MVFR/IFR CONDITIONS WILL PREVAIL THIS TAF PERIOD WITH NUMEROUS
SHOWERS AND THUNDERSTORMS TO AFFECT ALL AIRPORTS. BASED TIMING
HEAVILY ON THE HRRR MODEL...WITH ONE ROUND OF SHRA/TSRA ARRIVING
LATE WED MORN/EARLY AFT THEN MAIN ROUND OF SHRA/TSRA REACHING
TERMINALS BETWEEN 23-03Z. SOUTH WINDS UP TO 20 KTS WITH GUSTS TO
30 KTS TODAY AT AIRPORTS...ALTHOUGH GUSTY WINDS OVER 40KT POSSIBLE
IN ANY TSRA.
&&
.PRELIMINARY POINT TEMPS/POPS...
NASHVILLE 74 60 73 56 70 / 70 90 30 40 70
CLARKSVILLE 72 54 71 51 65 / 70 90 20 30 70
CROSSVILLE 69 62 71 59 69 / 50 80 70 40 70
COLUMBIA 73 61 74 57 71 / 70 90 40 40 70
LAWRENCEBURG 72 62 73 58 72 / 70 90 50 50 70
WAVERLY 72 55 70 52 68 / 80 80 20 40 70
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM/AVIATION........27/UNGER
LONG TERM..................21
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
618 AM CST WED DEC 23 2015
.UPDATE...
FOR 12Z AVIATION DISCUSSION.
&&
.DISCUSSION...
...SEVERE STORMS WITH TORNADOES POSSIBLE IN THE MID STATE THIS
AFTERNOON AND EVENING...
...SREF HAS SIGNIFICANT TORNADO PARAMETER AT 5 FOR MID STATE THIS
AFTERNOON AND EVENING...
...THE LAST TIME A TORNADO OCCURRED IN THE MONTH OF DECEMBER IN
TENNESSEE WAS BACK IN 2000 IN LINCOLN COUNTY...AND BEFORE THAT IN
1988 IN WILLIAMSON COUNTY...DECEMBER TORNADOES ARE SOMEWHAT
RARE...
FOR DISCUSSION PURPOSES WILL CONCENTRATE ON TODAY AND TONIGHT.
MADE ONLY MINOR TWEAKS TO THE EXTENDED. LONG WAVE TROUGH ACROSS
CENTRAL U.S. WILL AMPLIFY AS STRONG HEIGHT FALL CENTER IN EXCESS
OF 90 METERS PUSHES ACROSS NORTH TEXAS DURING THE DAY. UPPER
TROUGH WILL TAKE ON NEGATIVE TILT AS IT WORKS INTO OUR AREA THIS
AFTERNOON AND EVENING AS EMBEDDED SHORT WAVE SWINGS THIS WAY.
STRONG MOISTURE TRANSPORT WILL GET UNDERWAY DURING THE DAY FROM
GULF REGION DRIVING PRECIPITABLE WATER WELL ABOVE CLIIMATOLOGY FOR
THIS TIME OF THE YEAR. 60 DEGREE DEWPOINTS ALREADY IN PLACE WITH
CURRENT TEMPS IN THE LOW 60`S. 986 MBAR SURFACE LOW CENTER
CURRENTLY OVER WESTERN PANHANDLE OF OKLAHOMA...WARM FRONT DRAPED
FROM LOW CENTER ACROSS NORTHERN MISSOURI...SOUTHERN ILLINOIS THEN
UP INTO SOUTHERN INDIANA AND NORTHERN OHIO. MID STATE WILL BE IN
WARM SECTOR FOR THIS SEVERE WEATHER EVENT WITH MUCAPES ON THE
ORDER OF 500 TO 750 JOULES PER KILOGRAM AT 00Z TODAY. LIFTED
INDICES GO TO -4 THIS AFTERNOON/EVENING AS 850 MBAR JET CLIMBS TO
50-70 KNOTS AT 00Z. AS IF THIS IS NOT ENOUGH THE 700 MBAR TO 500
MBAR LAPSE RATES OFF 00Z OHX SOUNDING AT 7.7 DEGS CELSIUS PER
KILOMETER.
.CLIMATE...CHRISTMAS 1964...A TORNADO CUT A MILLION DOLLAR DAMAGE
PATH FROM WHISPERING HILLS SECTION OF NASHVILLE TO NEAR UNA...AT
11:50 PM CST CHRISTMAS NIGHT.
YEAR AND NUMBER OF TENNESSEE TORNADOES IN THE MONTH OF DECEMBER
SINCE 1950...
2000...1
1988...1 ONLY DECEMBER TORNADO FATALITY SINCE 1950
1987...1
1982...1
1978...2
1977...3
1973...2
1971...1
1967...3
1964...1
1957...3
&&
.AVIATION...
12Z TAF DISCUSSION.
MVFR/IFR CONDITIONS WILL PREVAIL THIS TAF PERIOD WITH NUMEROUS
SHOWERS AND THUNDERSTORMS TO AFFECT ALL AIRPORTS. BASED TIMING
HEAVILY ON THE HRRR MODEL...WITH ONE ROUND OF SHRA/TSRA ARRIVING
LATE WED MORN/EARLY AFT THEN MAIN ROUND OF SHRA/TSRA REACHING
TERMINALS BETWEEN 23-03Z. SOUTH WINDS UP TO 20 KTS WITH GUSTS TO
30 KTS TODAY AT AIRPORTS...ALTHOUGH GUSTY WINDS OVER 40KT POSSIBLE
IN ANY TSRA.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM/AVIATION........55/SHAMBURGER
LONG TERM..................01/BOYD
AREA FORECAST DISCUSSION...UPDATED
NWS MEMPHIS TN
550 AM CST WED DEC 23 2015
.UPDATE...
UPDATED FOR 12Z AVIATION DISCUSSION BELOW.
&&
.PREV DISCUSSION... /ISSUED 522 AM CST WED DEC 23 2015/
..OUTBREAK OF SEVERE THUNDERSTORMS EXPECTED ACROSS THE MID SOUTH
ESPECIALLY THIS AFTERNOON AND TONIGHT...
DISCUSSION...10Z SURFACE ANALYSIS PLACES A STRONG SURFACE LOW
ACROSS SOUTH CENTRAL KANSAS AND A DRYLINE EXTENDING SOUTH FROM
THE LOW ACROSS WESTERN OKLAHOMA AND WESTERN TEXAS. SOUTHERLY WINDS
IN ADVANCE OF THIS SURFACE LOW HAVE ALREADY ADVECTED LOWER TO
MIDDLE 60 DEWPOINT AIR UP INTO THE LOWER MISSISSIPPI VALLEY THIS
MORNING. WATER VAPOR SATELLITE TRENDS INDICATE A DEEP LONGWAVE
UPPER LEVEL TROUGH OVER THE CENTRAL AND SOUTHERN PLAINS AND A LEAD
SHORTWAVE TROUGH OVER THE LOWER MISSISSIPPI VALLEY. AT THE SURFACE A
WARM FRONT IS MOVING ACROSS THE MID SOUTH AS OF DISCUSSION.
CONSEQUENTLY...SHOWERS AND THUNDERSTORMS HAVE EXPANDED IN COVERAGE
ACROSS ARKANSAS OVERNIGHT. AS OF 4 AM CST...TEMPERATURES ACROSS
THE MID SOUTH ARE IN THE 60S AT MOST LOCATIONS. SEVERE
THUNDERSTORM POTENTIAL THIS AFTERNOON AND TONIGHT IS THE
PREDOMINANT FOCUS IN THIS MORNING/S FORECAST ISSUANCE.
SHOWERS AND THUNDERSTORMS OVER ARKANSAS AND SOUTHERN MISSISSIPPI
WILL SPREAD ACROSS THE MID SOUTH THIS MORNING. A STRONG TO SEVERE
THUNDERSTORM IS POSSIBLE THIS MORNING BUT THINK THE BULK OF THE
SEVERE THUNDERSTORM THREAT WILL OCCUR MAINLY THIS AFTERNOON AND
TONIGHT AS A NEGATIVELY TILTED UPPER LEVEL TROUGH AND A STRONG
COLD FRONT ROTATE THROUGH THE MIDDLE AND LOWER MISSISSIPPI
VALLEYS.
RECORD WARMTH WITH HIGHS TODAY IN THE LOWER TO MIDDLE 70S COMBINED
WITH FAVORABLE UPPER LEVEL DIVERGENCE PRODUCED BY THE RIGHT EXIT
REGION OF A 130 KT UPPER LEVEL JET...DECENT 50-80 DM 500 MB MID
LEVEL HEIGHT FALLS...SURFACE BASED CAPE VALUES BETWEEN 1500-2O00
J/KG...STEEP 700-500 MB LAYER MID LEVEL LAPSE RATES AROUND 7
C/KM...0-1 KM STORM RELATIVE HELICITIES AROUND 300
M2/S2...STRONGLY CURVED HODOGRAPHS...FAVORABLE LCL/S AND 0-6 KM
BULK SHEAR VALUES IN EXCESS OF 70 KTS SUGGESTS A VERY GOOD
POTENTIAL FOR THUNDERSTORMS TO BECOME SEVERE ACROSS THE MID SOUTH
ESPECIALLY DURING THE AFTERNOON AND EVENING HOURS. LARGE
HAIL...DAMAGING WINDS...AND TORNADOES ARE ALL POSSIBLE WITH ANY
THUNDERSTORMS THAT REACH SEVERE LIMITS. A POTENTIAL ALSO EXISTS
FOR SIGNIFICANT TORNADOES ACROSS MUCH OF THE MID SOUTH WITH THE
I-40 CORRIDOR IN THE CENTER OF THE RISK AREA. SHORT TERM MESOSCALE
TRENDS WILL CLOSELY BE MONITORED THROUGHOUT THE DAY IN CASE ANY
ADJUSTMENTS ARE NEEDED TO THE CURRENT FORECAST AND HAZARDOUS
WEATHER OUTLOOK. RESIDENTS OF THE MID-SOUTH AND HOLIDAY TRAVELERS
SHOULD STAY TUNED TO THE FORECAST TODAY AND BE PREPARED TO TAKE
APPROPRIATE SAFETY PRECAUTIONS IF SEVERE WEATHER THREATENS THEIR
LOCATION.
THE SEVERE THUNDERSTORM THREAT SHOULD BEGIN TO PUSH EAST OF THE
MID SOUTH TONIGHT AS A STRONG COLD FRONT SWEEPS THROUGH THE
AREA...BRINGING AN GRADUAL END TO SHOWER AND THUNDERSTORM CHANCES
BY CHRISTMAS EVE. HOWEVER...THIS IS NOT EXPECTED TO LAST LONG AS
THIS FRONT WILL STALL OUT AND RETURN BACK NORTH AS A WARM FRONT
CHRISTMAS EVE NIGHT INTO CHRISTMAS DAY. ANOTHER CHANCE FOR STRONG
TO SEVERE THUNDERSTORMS WILL BE POSSIBLE DURING THIS AND WILL BE
CLOSELY WATCHED IN UPCOMING FORECASTS.
LONG TERM MODELS INDICATE THE MID SOUTH WILL REMAIN IN A WARM
SECTOR FOR THE UPCOMING WEEKEND RESULTING IN A CONTINUED CHANCE
FOR SHOWERS AND THUNDERSTORMS. AN UPPER LEVEL LOW IS EXPECTED TO
DEVELOP AND MOVE FROM THE SOUTHERN PLAINS INTO THE MIDDLE/LOWER
MISSISSIPPI VALLEYS BY EARLY NEXT WEEK. THIS MAY POSE YET ANOTHER
POTENTIAL FOR STRONG TO SEVERE THUNDERSTORMS BETWEEN SUNDAY NIGHT
TO MONDAY NIGHT. CONFIDENCE IS LOW AT THIS MOMENT DUE TO
PERSISTENT RUN TO RUN CONTINUITY ISSUES WITH THIS PARTICULAR
SYNOPTIC SYSTEM. STAY TUNED...
CJC
&&
.AVIATION...
12Z TAFS
DEEP SUBTROPICAL MOISTURE WILL PREVAIL TODAY...WITH STRONG
VERTICAL WIND SHEER SUPPORTIVE OF A DEVELOPING LINE OF INTENSE
SURFACE-TSRA AFTER 18Z. HRRR AND NAM INDICATED A BROKEN LINE OF
TSRA. FOR THIS MORNING...SHRA/TSRA WILL BE ROOTED IN AN ELEVATED
LAYER ABOVE THE MOIST LOW LEVEL INVERSION.
PROSPECTS FOR A MVFR/VFR LATE EVENING MEM ARRIVAL PUSH APPEAR
PROMISING...ASSUMING POST FRONTAL STRATUS DEPICTED ON THE 06Z NAM
BUFR SOUNDINGS DOES NOT MATERIALIZE.
PWB
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
533 AM CST WED DEC 23 2015
.AVIATION...
A S/WV TROUGH WILL MOVE EAST OF THE REGION TODAY. STILL SOME
POTENTIAL FOR A FEW SHOWERS OVER THE NORTHERN TAF SITES THIS
MORNING. MUCH DRIER AIR WILL WORK INTO THE REGION FROM THE WEST BY
AFTERNOON WITH SFC WINDS VEERING TO THE W-SW. VFR CONDS EXPECTED
TO DEVELOP BETWEEN 17-19Z AREAWIDE. FCST SOUNDINGS SHOW CLEAR
SKIES OVERNIGHT. COASTAL TAF SITES MAY SUFFER SOME VSBY
RESTRICTIONS LATE TONIGHT. THE HRRR SHOWS AN AREA OF SEA FOG
DEVELOPING OFF THE LOUISIANA COAST AND MOVING WEST TONIGHT. THE
FOG WILL PROBABLY IMPACT KGLS/KLBX AFTER 08Z AND KHOU AFTER 10Z.
43
&&
.PREV DISCUSSION... /ISSUED 509 AM CST WED DEC 23 2015/
SHORT TERM /TODAY THROUGH CHRISTMAS EVE DAY/...
REGARDING TORNADO WATCH 556... THERE HAS BEEN LIMITED CONVECTIVE
DEVELOPMENT OVER THE WATCH AREA OVER THE PAST FEW HOURS. DESPITE
SUFFICIENT FORCING FOR ASCENT AHEAD OF A SHORTWAVE TROUGH SWINGING
ACROSS THE SOUTHERN PLAINS... A RELATIVELY STABILIZED ATMOSPHERE
APPEARS TO BE LIMITING ADDITIONAL DEVELOPMENT. AFTER COORDINATION
WITH SPC... HAVE OPTED TO CANCEL THE WATCH WITH THE MORNING
PACKAGE. CANNOT RULE OUT AN ISOLATED SHOWER OR STORM DEVELOPING
THROUGH THE REMAINDER OF THE EARLY MORNING HOURS OVER THE
NORTHEASTERN COUNTIES HOWEVER.
FOR THE REMAINDER OF TODAY... A SURFACE LOW PRESSURE SYSTEM
LOCATED OVER NORTHWEST OKLAHOMA/ WESTERN KANSAS INDUCED BY THE
SHORTWAVE TROUGH WILL EJECT NORTHEAST TOWARDS MISSOURI. THIS WILL
DRAG AN ATTENDANT SURFACE TROUGH ACROSS TEXAS... WITH A TIGHT
PRESSURE GRADIENT IN RESPONSE TO THE SURFACE LOW RESULTING IN
ELEVATED SOUTHERLY WINDS ACROSS SOUTHEAST TEXAS FOR MOST OF THE
DAY. AS THE SURFACE TROUGH MOVES INTO THE REGION LATER THIS
MORNING... SOME HIGH RESOLUTION GUIDANCE BREAKS OUT SCATTERED
SHOWERS ALONG AND AHEAD OF THIS FEATURE. BEST CHANCES /30-40 POPS/
APPEAR TO BE NORTH OF THE INTERSTATE 10 AND WEST OF THE
INTERSTATE 45 CORRIDORS WITH AN ISOLATED LIGHTNING STRIKE OR TWO
ALSO POSSIBLE WITH MID-LEVEL LAPSE RATES AROUND 7 TO 7.5 J/KG.
UPPER FORCING ASSOCIATED WITH THE SOUTHERN PLAINS SHORTWAVE IS
EXPECTED TO LIFT NORTHEAST OF THE REGION BY MIDDAY AND LOSS OF
THIS FORCING COUPLED WITH DRIER AIR BEHIND THE SURFACE TROUGH IS
EXPECTED TO END RAIN CHANCES BY THIS AFTERNOON.
CLOUDS ARE ALSO EXPECTED TO CLEAR FROM WEST TO EAST DURING THE DAY AS
DRIER AIR MOVES INTO THE REGION... AND THIS WILL ALLOW THE REGION
TO TAKE ADVANTAGE OF ENOUGH INSOLATION FOR AFTERNOON TEMPERATURES
TO RISE INTO THE UPPER 70S TO EVEN LOW 80S. MOSTLY CLEAR TO PARTLY
CLOUDY SKIES AND DRIER CONDITIONS WILL ALLOW OVERNIGHT LOWS TO
FALL A FEW DEGREES BELOW WHAT WE/LL OBSERVE THIS MORNING /NEAR
RECORD MAXIMUM LOW TEMPERATURES POSSIBLE IN A FEW LOCATIONS/.
CHRISTMAS EVE DAY WILL BE A RELATIVELY DRY ONE FOR THE REGION...
WITH ONLY ISOLATED WARM AIR ADVECTION SHOWERS POSSIBLE DURING THE
DAY AS A SURGE OF MOISTURE MOVES IN OFF THE GULF. THIS MOISTURE WILL
ALSO RESULT IN INCREASING CLOUDS... WITH TEMPERATURES ON CHRISTMAS
EVE DAY STILL WARM BUT A DEGREE OR TWO COOLER THAN TODAY OWING TO
CLOUD COVER.
HUFFMAN
LONG TERM /CHRISTMAS EVE NIGHT THROUGH TUESDAY/...
BY CHRISTMAS EVE NIGHT... AN INCREASING LOW LEVEL JET ACROSS THE
REGION WILL PUSH MORE GULF MOISTURE INTO THE REGION AND RESULT IN
SHOWER AS WELL AS THUNDERSTORM DEVELOPMENT. INCREASING SHEAR AS
THE LOW LEVEL JET INTENSIFIES WILL POSSIBLY CREATE THE POTENTIAL
FOR ORGANIZED STORMS /SOME POSSIBLY STRONG/ GENERALLY EAST OF
INTERSTATE 45 EARLY CHRISTMAS MORNING... BUT WITH BEST JET
DYNAMICS NORTH OF THE REGION CONFIDENCE IS LOW IN OCCURRENCE AT
THIS TIME.
FOR CHRISTMAS... WAVES OF SHOWERS AND THUNDERSTORMS WILL CONTINUE
TO MOVE ACROSS THE REGION FROM SOUTH TO NORTH DURING THE DAY WITH
HIGH TEMPERATURES TOPPING OUT IN THE MID 70S TO NEAR 80. FOR WHAT
IT IS WORTH... THE AVERAGE HIGH FOR HOUSTON ON CHRISTMAS IS 61.2
DEGREES.
THIS WEEKEND... ATTENTION TURNS TO A MAJOR STORM SYSTEM
APPROACHING TEXAS BY SATURDAY. DIFFERENCES STILL EXIST IN THE
SPEED/TIMING OF THE SYSTEM... WITH THE CANADIAN/EUROPEAN SIDING
WITH A MORE SOUTHERLY AND SLOWER PATH OF THE UPPER TROUGH ACROSS
TEXAS AND THE GFS SOMEWHAT QUICKER AND FARTHER NORTH.
REGARDLESS... THE GENERAL TREND IN GUIDANCE IS FOR THE UPPER
TROUGH TO BECOME NEGATIVELY TILTED OVER THE REGION DURING THE LATE
WEEKEND /SUNDAY INTO EARLY MONDAY/. THIS OFFERS SOME INCREASING
CONFIDENCE FOR A SEVERE WEATHER THREAT FOR MUCH OF THE REGION ON
SUNDAY... POSSIBLY WITH DISCRETE THUNDERSTORMS AHEAD OF A SQUALL
LINE AND ATTENDANT COLD FRONT DURING THE LATE WEEKEND. WILL ALSO
NEED TO MONITOR FOR THE POTENTIAL OF AT LEAST A LOCALIZED HEAVY
RAIN THREAT WITH FORECAST PRECIPITABLE WATER VALUES NEARING THE
99TH PERCENTILE ACROSS MUCH OF THE REGION SATURDAY AND SUNDAY.
FOR THE BEGINNING OF NEXT WEEK... DRIER AND COOLER AIR BEHIND
THE LATE WEEKEND FRONT WILL KEEP THE BEGINNING OF NEXT WEEK DRY.
MEDIUM RANGE GUIDANCE CONTINUES TO TREND TEMPERATURES DOWN FOR
THIS PORTION OF THE FORECAST... WITH BELOW NORMAL TEMPERATURES
POSSIBLE FOR THE LAST FEW DAYS OF DECEMBER.
HUFFMAN
MARINE...
WILL MAINTAIN THE SCA FOR THE 20-60 NM WATERS AS WINDS INCREASE IN
RESPONSE TO A DEEPENING AREA OF LOW PRESSURE OVER THE SOUTHERN
PLAINS. THE STRONGEST WINDS ARE EXPECTED THIS MORNING WITH SOME
DECREASE IN SPEEDS BY LATE AFTN. A FLATTER PRESSURE GRADIENT IS
EXPECTED TONIGHT AND THURSDAY AND WINDS WILL RELAX. THE LULL IN
HIGHER IN WIND SPEEDS WILL BE SHORT LIVED AS THE GRADIENT TIGHTENS
IN RESPONSE TO YET ANOTHER AREA OF LOW PRESSURE DEVELOPING OVER THE
WESTERN PLAINS ON FRIDAY. SCEC CONDITIONS POSSIBLE BY FRIDAY AFTN
OVER THE 20-60 NM WATERS WITH SCA CONDS LIKELY OVER THE 20-60 NM
WATERS BOTH SAT/SUN. CONDITIONS REMAIN SOMEWHAT FAVORABLE FOR SEA
FOG THROUGH THE WEEKEND AS SFC DEW PTS REMAIN 6-10 DEGREES WARMER
THAN THE WATER TEMP BUT IDEAL CONDITIONS WOULD HAVE MORE OF AN EAST
WIND AND NOT S-SE.
A STRONG COLD FRONT WILL CROSS THE COASTAL WATERS SUNDAY NIGHT OR
EARLY MONDAY MORNING. A LINE OF STRONG STORMS IS EXPECTED ALONG THE
FRONT AND AN ABRUPT WIND SHIFT TO THE WEST-NORTHWEST IN THE WAKE OF
THE FRONT. 43
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 79 55 77 65 78 / 20 10 10 40 50
HOUSTON (IAH) 82 56 80 67 79 / 30 10 20 40 50
GALVESTON (GLS) 77 63 74 67 74 / 20 10 20 40 50
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT SHOULD EXERCISE CAUTION UNTIL NOON CST TODAY FOR THE
FOLLOWING ZONES: GALVESTON BAY...MATAGORDA BAY...WATERS
FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT 20 NM...
WATERS FROM HIGH ISLAND TO FREEPORT OUT 20 NM.
SMALL CRAFT ADVISORY UNTIL NOON CST TODAY FOR THE FOLLOWING
ZONES: WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL
20 NM TO 60 NM...WATERS FROM HIGH ISLAND TO FREEPORT 20 TO
60 NM.
&&
$$
DISCUSSION...14
AVIATION/MARINE...43
AREA FORECAST DISCUSSION
NWS MIAMI FL
143 PM EST WED DEC 23 2015
.AVIATION...
HIGH PRESSURE TO THE EAST WILL KEEP THE WIND OUT OF THE SOUTHEAST
THROUGH THE TAF PERIOD. EXPECT MOSTLY DRY CONDITIONS, BUT AN
ISOLATED SHOWER IS POSSIBLE. CURRENT FORECAST IS FOR VFR THROUGH
THE TAF PERIOD, BUT SOME LOCALIZED IFR DUE TO CIGS MAY BE POSSIBLE
ACROSS SOUTH FLORIDA, ESPECIALLY IN THE EARLY MORNING HOURS. THERE
IS ALSO A POSSIBILITY OF SOME FOG IN THE MORNING, MAINLY AT KAPF.
&&
.PREV DISCUSSION... /ISSUED 1108 AM EST WED DEC 23 2015/
UPDATE...
HIGH PRESSURE REMAINS IN CONTROL OF THE WEATHER PATTERN FOR SOUTH
FLORIDA TODAY. THIS WILL KEEP THE SOUTHEASTERLY WIND OVER THE
REGION. THIS WILL ALSO KEEP TEMPERATURES ON THE WARM SIDE FOR THE
NEXT FEW DAYS. WHILE NOT EXPECTING ANY SIGNIFICANT COVERAGE OF
SHOWERS, THERE IS A SLIGHT CHANCE OF SOME POP UP SHOWERS ACROSS
THE EASTERN HALF OF THE AREA. THE HRRR SHOWS INITIATION MAY BEGIN
EARLY THIS AFTERNOON. SO, HAVE KEPT THE 20 POPS ACROSS MOST OF THE
CWA. ALSO, THE RIP CURRENT RISK REMAINS HIGH TODAY, AND WILL
REMAIN ELEVATED THROUGH THE WEEKEND.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 77 86 77 86 / 10 10 20 20
FORT LAUDERDALE 77 84 76 83 / 10 10 20 20
MIAMI 77 86 77 84 / 10 10 20 20
NAPLES 70 88 70 86 / 0 10 10 10
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...HIGH RIP CURRENT RISK THROUGH THURSDAY EVENING FOR FLZ168-172-
173.
AM...NONE.
GM...NONE.
&&
$$
SHORT TERM...13/SI
LONG TERM....60/BD
AVIATION...13/SI
AREA FORECAST DISCUSSION
NWS MIAMI FL
1108 AM EST WED DEC 23 2015
.UPDATE...
HIGH PRESSURE REMAINS IN CONTROL OF THE WEATHER PATTERN FOR SOUTH
FLORIDA TODAY. THIS WILL KEEP THE SOUTHEASTERLY WIND OVER THE
REGION. THIS WILL ALSO KEEP TEMPERATURES ON THE WARM SIDE FOR THE
NEXT FEW DAYS. WHILE NOT EXPECTING ANY SIGNIFICANT COVERAGE OF
SHOWERS, THERE IS A SLIGHT CHANCE OF SOME POP UP SHOWERS ACROSS
THE EASTERN HALF OF THE AREA. THE HRRR SHOWS INITIATION MAY BEGIN
EARLY THIS AFTERNOON. SO, HAVE KEPT THE 20 POPS ACROSS MOST OF THE
CWA. ALSO, THE RIP CURRENT RISK REMAINS HIGH TODAY, AND WILL
REMAIN ELEVATED THROUGH THE WEEKEND.
&&
.PREV DISCUSSION... /ISSUED 600 AM EST WED DEC 23 2015/
AVIATION...
LESS SHOWER COVERAGE EXPECTED TODAY WITH LOWER POPS, AS A
RELATIVELY DRIER AIRMASS ARRIVES. STILL SOME MVFR CIGS ARE
POSSIBLE EARLY, ESPECIALLY AT APF. SUSTAINED WINDS MAY BE NEAR 20
KTS AT TIMES WITH GUSTS NEAR 30 KTS ALONG THE IMMEDIATE EAST COAST
TERMINALS PBI/FLL/FXE. WINDS WEAKEN SOMEWHAT TONIGHT. THERE COULD
ANOTHER ROUND OF MVFR CIGS AT APF LATE TONIGHT.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 87 77 86 77 / 20 10 10 20
FORT LAUDERDALE 83 77 84 76 / 20 10 10 20
MIAMI 85 77 86 77 / 20 10 10 20
NAPLES 87 70 88 70 / 10 0 10 10
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...HIGH RIP CURRENT RISK THROUGH THURSDAY EVENING FOR FLZ168-172-
173.
AM...NONE.
GM...NONE.
&&
$$
SHORT TERM...13/SI
LONG TERM....60/BD
AREA FORECAST DISCUSSION
National Weather Service Lincoln IL
501 PM CST WED DEC 23 2015
.SHORT TERM...(Tonight)
ISSUED AT 312 PM CST WED DEC 23 2015
First round of severe weather has exited the eastern forecast area
early this afternoon, but storms have quickly started to fire in
northeast Missouri. This particular area has seen some sunshine
during the afternoon, helping to destabilize the atmosphere, where
CAPE`s are above 500 J/kg and 0-6km bulk shear is an impressive 60-
70 knots. HRRR latched onto this area of development earlier, and
races it across the northern part of the forecast area between 4 pm
and 8 pm. Have concentrated the highest PoP`s for the rest of the
afternoon in this area. The storms should be weakening after sunset
as the surface low pulls northeast, and there is some question about
how much the atmosphere across the eastern CWA can recover after
being thoroughly worked over the last several hours.
Secondary concern is with the winds this evening. Have issued a Wind
Advisory for the period from 6 pm to 2 am across about the northwest
half of the forecast area. Main surface low is currently located
across northeast Iowa, and will be zipping northeast. Impressive 3-
hour pressure rises of 10-11 mb are progged to track northeastward
to around Rockford by midnight. Wind gusts of 45 mph or so are
likely across the northwest half of the forecast area as this
bullseye passes. Have gone as far south as Jacksonville with the
advisory, but this area may be of a shorter duration. Most of the
winds should be diminishing around midnight, but will linger a bit
longer north of I-74.
.LONG TERM...(Thursday through Wednesday)
ISSUED AT 312 PM CST WED DEC 23 2015
Short and medium range models are in fairly good agreement with the
overall active weather pattern through the weekend and into early
next week. Unseasonably warm temperatures and very wet weather will
be the main factors for the weekend through late Monday.
In the shorter term, mild temperatures and periods of cloudiness can
be expected for Christmas Eve into much of Christmas Day. The return
of a surface boundary north of the Ohio Valley and associated weak
isentropic lift initially will result in a chance for light rain in
southeast IL late on Christmas Day. The GFS is the odd model out on
this one by keeping the boundary much farther south.
Backing upper level flow in response to a digging trough in the
western U.S. will allow very warm and moist air to return into much
of central and SE IL during the day Saturday. This feed of moisture
and the associated rainfall will linger in the forecast area through
most of Sunday, resulting in 2.50 to 3.50 inches of rain. The
precipitation area will gradually sag south as the upper low in the
west closes off in SW Texas and an upper level confluent area sets
up across central IL by later in the day Sunday.
The upper low in the southwestern U.S. is expected to kick out
toward the Midwest Monday as another strong upper level trough digs
from the Pacific NW to the southern Plains. This will bring the
likelihood of precipitation back to central IL for Monday. The
forecast type becomes a bit tricky north of a Rushville-Bloomington
line Monday into Monday night as upper level soundings indicate a
mix of rain/snow/sleet possible. Could be some minor accumulations
of snow NW of Peoria late Monday, but there is a lot of uncertainty
with this scenario 6 days out.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
ISSUED AT 500 PM CST WED DEC 23 2015
Cold front pushing into extreme west central Illinois will sweep
across the forecast area over the next several hours accompanied
by widely scattered showers and storms and strong gradient winds.
Look for south winds to veer more south-southwest and increase
to between 25 to 35 kts with gusts near 45 kts at times before
diminishing after 07z. Latest satellite data and surface obs to
our west indicate another band of MVFR cigs approaching the river
and based on timing, should begin to affect PIA and SPI by 01z,
BMI to CMI by 02z. Bases should run from 1000-2000 feet with about
a 3-5 hour stay in our TAF area before VFR conditions return after
07z.
&&
.ILX Watches/Warnings/Advisories...
Wind Advisory until 2 AM CST Thursday for ILZ027>031-036>038-
040>043-047>050.
&&
$$
SHORT TERM...Geelhart
LONG TERM...Miller
AVIATION...Smith
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
413 PM CST WED DEC 23 2015
.MESOSCALE DISCUSSION...
242 PM CST
FIRST ROUND OF THUNDERSTORMS HAS PUSHED OFF TO THE EAST WITH
STRATIFORM RAIN IN PLACE ACROSS PORTIONS OF EAST CENTRAL ILLINOIS
AND NORTHWEST INDIANA. LOW PRESSURE IS ANALYZED JUST SOUTH OF
KDSM THIS AFTERNOON WITH A FRONTAL BOUNDARY STRETCHING SOUTH
ACROSS MISSOURI. VISIBLE SATELLITE IMAGERY SHOWS TOWERING CU AND A
FEW CB/S IMMEDIATELY AHEAD OF THE FRONT WHERE SURFACE TEMPS ARE IN
THE MID 60S AND DEWPOINTS IN THE LOW TO MID 50S. 18Z SPECIAL
SOUNDING OUT OF KDVN SHOWED AROUND 250 J/KG SBCAPE WITH FAIRLY
INTENSE DEEP LAYER SHEAR IN EXCESS OF 70KT. WATER VAPOR IMAGERY
SHOWS A DRY SLOT WRAPPING INTO NORTHEASTERN MISSOURI AND
SOUTHEASTERN COINCIDENT WITH THE CORRIDOR OF MODEST INSTABILITY OF
200-600 J/KG MLCAPE WHICH RAP GUIDANCE SHOWS LIFTING ACROSS
PORTIONS OF NORTH CENTRAL ILLINOIS WITHIN THE NEXT FEW HOURS.
STRONG PRESSURE FALLS AHEAD OF THE LOW MAY HELP TO KEEP WINDS
BACKED ACROSS NORTH CENTRAL ILLINOIS WHICH WILL LOCALLY ENHANCE
THE THREAT FOR SUPERCELLS ALONG WITH THE POSSIBILITY OF AN
ISOLATED TORNADO. A BIT HARD TO TELL HOW FAR EAST THE SEVERE
THREAT WILL EXTEND THIS AFTERNOON AND EVENING...THOUGH HI- RES
MODELS HAVE CONSISTENTLY SHOWED A WEAKENING TREND AS THUNDERSTORMS
APPROACH THE CHICAGO METRO AREA THIS EVENING. FOR NOW AM MOST
CONCERNED ABOUT SEVERE WEATHER WEST OF A PONTIAC TO WOODSTOCK
LINE...BUT CERTAINLY NOT OUT OF THE WOODS FARTHER EAST.
DEUBELBEISS
&&
.SHORT TERM...
236 PM CST
THROUGH THURSDAY...
A DEEP UPPER TROUGH IS OVER THE CENTRAL CONUS WITH A STRONG MID
LEVEL SHORTWAVE TRACKING NEWD THROUGH THE UPPER MISSOURI VALLEY. A
SERIES OF WEAKER SHORTWAVES HAVE BEEN TRACKING NEWD THROUGH THE
MIDDLE MISSISSIPPI VALLEY...GENERATING SCT STRONG THUNDERSTORMS AS
FAR NORTH AS NERN IL AND NWRN IN EARLIER TODAY. THE SRN STREAM
SHORTWAVE ENERGY IS BEGINNING TO FOCUS TSRA OVER THE LOWER OHIO
VALLEY AND INTO INDIANA THIS AFTERNOON AND THE MAIN AREA OF CONCERN
WITH RESPECT TO TSRA ACTIVITY FOR THE LOCAL AREA WILL BE UNDER THE
MID LEVEL CIRCULATION CENTER. UNDER THE COLD CORE UPPER LOW AND
WITH UNSEASONABLY WARM...MOIST AIR IN PLACE OVER THE REGION...STRONG
LAPSE RATES AND MODEST LOW LEVEL INSTABILITY WILL KEEP A CHANCE FOR
THUNDERSTORMS INTO THE EVENING HOURS. THE LATEST SATELLITE IMAGERY
SHOWS SOME BREAKS IN THE OVERCAST UNDER THE UPPER LOW WITH SOME
CONVECTIVE CLOUD DEVELOPMENT APPARENT. SOME OF THIS ACTIVITY IS
ALREADY GENERATING LIGHTNING OVER IOWA AND NERN MO. LATEST SPC
MESOSCALE ANALYSIS INDICATES AN AREA OF LOW LEVEL INSTABILITY
CONSISTENT WITH THE CURRENT CONVECTIVE DEVELOPMENT AND THE SHORT
RANGE HIGH RES MODEL GUIDANCE INDICATES THAT THERE IS A CHANCE FOR
THUNDERSTORM ACTIVITY TO MAINTAIN INTO THE EVENING HOURS...MOSTLY
ACROSS NRN IL. ALSO...MORNING SOUNDINGS INDICATE STRONG VERTICAL
SHEAR FROM THE SFC THROUGH MID LEVELS...SO LOW-TOPPED SUPERCELL
DEVELOPMENT REMAIN A POSSIBILITY STRONG...DAMAGING WIND...ISOLATED
LARGE HAIL AND A FEW TORNADOES WILL REMAIN A POSSIBILITY INTO THE
EVENING.
ANOTHER CONCERN FOR THE EVENING AND INTO THE OVERNIGHT HOURS WILL BE
STRONG SYNOPTIC SCALE WINDS. AS THE MAIN SFC LOW QUICKLY LIFTS NEWD
FROM ERN IOWA THIS AFTERNOON TO LAKE SUPERIOR WHILE DEEPENING AT
LEAST 10MB BY ARND 06Z...STRONG PRESSURE RISES IN THE WAKE OF THE
LOW WILL HELP GENERATE STRONG SLWY-WLY WINDS WITH SUSTAINED SPEEDS
ARND 30 MPH AND GUSTS OF 40-50 MPH. THE PERIOD OF THE STRONGEST
WINDS WILL BE FROM ARND 03-09Z WHICH WILL BE THE PERIOD OF THE
STRONGEST PRESSURE RISES.
FOR THURSDAY...CONDITIONS WILL BE MUCH QUIETER AS HIGH PRESSURE
BUILDS ACROSS THE REGION. EVEN WITH A STRONG COLD FRONT EXPECTED TO
MOVE ACROSS THE REGION AS THE SFC LOW LIFTS TO THE
NORTHEAST...TEMPERATURES WILL REMAIN ABOVE SEASONABLE NORMAL LEVELS
WITH HIGHS RANGING FROM AROUND 40F OVER THE ROCKFORD AREA TO THE
UPPER 40S SOUTH OF A VALPARAISO TO PONTIAC LINE.
KREIN
&&
.LONG TERM...
THURSDAY NIGHT THROUGH WEDNESDAY...
259 PM...TWO STORM SYSTEMS TO AFFECT THE REGION...FIRST SATURDAY
INTO SATURDAY NIGHT WITH HEAVY RAIN POSSIBLE ESPECIALLY ACROSS THE
SOUTHERN CWA. SECOND STORM SYSTEM MONDAY INTO TUESDAY...WITH
UNCERTAINTY REGARDING TIMING AND PRECIP TYPE.
HIGH PRESSURE WILL BE MOVING ACROSS THE AREA THURSDAY NIGHT INTO
FRIDAY WITH DRY CONDITIONS EXPECTED THROUGH FRIDAY EVENING. LIGHT
WINDS AND AT LEAST SOME PARTIAL CLEARING THURSDAY NIGHT SHOULD
ALLOW TEMPS TO DROP INTO THE UPPER 20S/LOWER 30S. HIGHS BACK IN
THE 40S ON CHRISTMAS DAY WITH INCREASING CLOUDS BY AFTERNOON/
EVENING AHEAD OF THE NEXT SYSTEM.
NEXT STORM SYSTEM BEGINS TO AFFECT THE AREA LATE FRIDAY NIGHT BUT
MORESO INTO SATURDAY WITH A COLD FRONT SLOWLY SAGGING THROUGH THE
AREA AND EVENTUALLY SOUTH OF THE AREA SATURDAY NIGHT. HOW FAST THIS
BOUNDARY SAGS SOUTH...OR ANY OTHER CHANGES TO ITS SPEED/LOCATION MAY
HAVE LARGE IMPACTS ON WHERE A BAND/CORRIDOR OF VERY HEAVY RAIN SETS
UP. CURRENTLY APPEARS TO BE ACROSS CENTRAL ILLINOIS INTO CENTRAL
INDIANA...INCLUDING THE FAR SOUTHEAST CWA. ITS POSSIBLE 1 TO 2
INCHES OF RAIN MAY FALL ACROSS THIS AREA THROUGH SATURDAY NIGHT
WITH AMOUNTS DECREASING ACROSS NORTHERN IL. THIS ADDITIONAL
RAINFALL MAY BOTH EXTEND CURRENT ELEVATED RIVER LEVELS AND CAUSE
POSSIBLE NEW RISES. THERMALLY...WHILE SURFACE WINDS SHIFT
NORTHERLY AND COOLER AIR SPREADS ACROSS THE REGION...IT APPEARS
THE BULK OF THIS PRECIP WILL FALL AS RAIN. HOWEVER...BY SUNDAY
MORNING...DEPENDING ON HOW MUCH PRECIP IS STILL OCCURRING...THERE
COULD BE A MIX WITH LIGHT SNOW. THOUGH PRECIP MAY END BEFORE IT
BECOMES COLD ENOUGH FOR A MIX WITH SNOW.
MAINTAINED LOW CHANCE POPS SUNDAY NIGHT BUT THIS TIME PERIOD IS ALSO
NOW LOOKING TO BE MAINLY DRY...WITH PERHAPS THE BEST CHANCE OF ANY
PRECIP ACROSS THE FAR SOUTHERN CWA AND TOWARD MONDAY MORNING. IF ANY
PRECIP DOES OCCUR SUNDAY NIGHT...THERE COULD BE SOME MIX OF SNOW OR
SLEET. WHILE THERE IS FAIR CONSISTENCY WITH PRECIP SPREADING BACK
ACROSS THE AREA MONDAY AND THEN PRECIP LIKELY MONDAY NIGHT...THE
TRACK OF THE LOW AND THUS THE EXTENT OF WARM AIR AND THEREFORE
PRECIP TYPE BECOMES QUITE UNCERTAIN. THE GEM/GFS ARE SIMILAR AND
COLDER WHILE THE ECMWF IS WARMER. A BLEND OF THESE SOLUTIONS IS IN
FAIR AGREEMENT WITH THE PREVIOUS FORECAST WHICH MAINTAINS A MIX OF
RAIN AND SNOW MONDAY AND MONDAY NIGHT. THERE IS SOME POTENTIAL FOR
SLEET AND PERHAPS FREEZING RAIN BUT GIVEN THE THERMAL
UNCERTAINTY... ITS TOO EARLY FOR DETAILS. HOWEVER...IF STRONG
PERSISTENT NORTHEAST WINDS DO DEVELOP...THIS WILL MAINTAIN A
DRIER...COOLER INFLOW AND ONCE PRECIP STARTS...EVAPORATIVE COOLING
MAY BE SUFFICIENT FOR AT LEAST A WINTERY MIX AND PERHAPS A PERIOD
OF SNOW. SMALL CHANGES IN THE TRACK WILL RESULT IN LARGE CHANGES
TO THE FORECAST.
COLDER AIR THEN APPEARS TO SPREAD BACK ACROSS THE AREA BY MID WEEK
NEXT WEEK WITH A WEAK DISTURBANCE THAT WILL LIKELY RESULT IN AT
LEAST A CHANCE OF LIGHT SNOW OR SNOW SHOWERS. CMS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 22Z...
* POTENTIAL FOR A FEW ADDITIONAL STRONG STORMS EARLY THIS EVENING
(01-03 UTC).
* STRONG GUSTY SOUTH WINDS 25-30 KT THIS AFTERNOON.
* POTENTIAL FOR VERY STRONG SOUTHWESTERLY WINDS FOR A SHORT PERIOD
THIS EVENING BETWEEN 03-06 UTC. GUSTS OF 45 TO 50 KT POSSIBLE
DURING THIS PERIOD.
KJB/RATZER
//DISCUSSION...UPDATED 18Z...
A SIGNIFICANT STORM SYSTEM WILL CONTINUE TO IMPACT THE REGION INTO
TONIGHT. THE MAIN AVIATION WEATHER CONCERNS WILL BE THE POTENTIAL
FOR ADDITIONAL SCT STRONG THUNDERSTORMS EARLY THIS EVENING...GUSTY
SOUTH WINDS THIS AFTERNOON...FOLLOWED BY A PERIOD OF VERY STRONG
GUSTY SYNOPTIC SOUTHWESTERLY WINDS LATER THIS EVENING.
CURRENTLY AN AREA OF MAINLY SHOWERS...WITH A FEW EMBEDDED
THUNDERSTORMS...CONTINUES TO MOVE ACROSS THE EASTERN AIRFIELDS AS A
WARM FRONT GRADUALLY SHIFTS NORTHWARD OVER THE AREA. THIS SHOWERS
ACTIVITY WILL BEGIN TO MOVE OUT OF THE AREA AROUND...OR SLIGHTLY
AFTER THE 19 UTC HOUR...WITH ONLY SOME WIDELY SCT SHOWERS POSSIBLE
THEREAFTER. CIGS AND VSBYS WILL ALSO BE IMPROVING THIS
AFTERNOON...THOUGH THE SURFACE WINDS WILL CONTINUE TO BECOME DUE
SOUTHERLY AND GUSTY...UP AROUND 30 KT THROUGH THE REST OF THE
AFTERNOON.
ANOTHER BATCH OF SCATTERED THUNDERSTORMS MAY DEVELOP VERY LATE THIS
AFTERNOON OVER WESTERN ILLINOIS AHEAD OF AN APPROACHING COLD FRONT.
THESE STORMS COULD THEN PROGRESS EAST-NORTHEASTWARD OVER THE EASTERN
TERMINALS EARLY THIS EVENING...ROUGHLY BETWEEN 00 AND 03 UTC THIS
EVENING. THE POTENTIAL FOR STORMS AT A GIVEN TERMINAL WILL LIKELY BE
FAIRLY SHORT (UNDER AN HOUR)...THOUGH EXACT TIMING REQUIRES A 2 HOUR
TEMPO AT THIS RANGE. THESE POTENTIAL STORMS ALSO HAVE A CONDITIONAL
RISK OF BEING SEVERE WITH STRONG SURFACE WINDS.
FOLLOWING THE COLD FRONTAL PASSAGE...AROUND 02-03 UTC THIS
EVENING...IT APPEARS THAT THE SURFACE WINDS OUTSIDE OF THUNDERSTORMS
COULD BECOME VERY STRONG FOR A SHORT PERIOD. VERY STRONG PRESSURE
RISES LOOK TO OVERSPREAD THE AREA BEHIND THIS FRONT...AND THIS COULD
LEAD TO VERY EFFICIENT TRANSPORT OF STRONGER WINDS ALOFT TO THE
SURFACE MID TO LATE THIS EVENING. WIND GUSTS COULD BRIEFLY GUST IN
THE 45 TO 50 KT RANGE DURING THIS PERIOD...BEFORE ABATING
OVERNIGHT.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 22Z...
* MEDIUM-HIGH WITH TSRA/TIMING THIS EVENING.
* MEDIUM HIGH WITH WIND FORECAST.
KJB/RATZER
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT...VFR.
FRIDAY...VFR.
SATURDAY...SHOWERS. CHANCE OF MVFR/IFR.
SUNDAY...CHANCE OF RAIN/SNOW/SLEET AND MVFR CIGS.
MONDAY...CHANCE OF RAIN/SNOW/SLEET AND MVFR CIGS.
TUESDAY...CHANCE OF RAIN/SNOW AND MVFR CIGS.
RODRIGUEZ
&&
.MARINE...
413 PM...DEEP LOW PRESSURE OVER EASTERN IOWA WILL MOVE NORTH
ACROSS LAKE SUPERIOR TONIGHT REACHING JAMES BAY THURSDAY. THIS LOW
WILL CONTINUE TO DEEPEN AND COMBINED WITH STRONG PRESSURE RISES
AND COLD AIR...VERY STRONG WINDS WILL DEVELOP THIS EVENING WITH
STORM FORCE WINDS LIKELY. THESE ARE EXPECTED TO DROP BACK TO GALES
BY MORNING WITH GALE FORCE WINDS STEADILY DIMINISHING THURSDAY
MORNING FROM SOUTH TO NORTH ACROSS THE LAKE. HIGH PRESSURE WILL
MOVE ACROSS THE LAKES REGION FRIDAY AND FRIDAY NIGHT. STRONG HIGH
PRESSURE WILL THEN MOVE ACROSS SOUTHERN CANADA AND THE NORTHERN
PLAINS THIS WEEKEND AS WEAK LOW PRESSURE MOVES ACROSS THE OHIO
VALLEY. THIS WILL STRENGTHEN A NORTHEAST GRADIENT ACROSS THE
REGION WITH SPEEDS INCREASING TO 30 KTS SUNDAY NIGHT INTO MONDAY
WITH GALES POSSIBLE MONDAY NIGHT ON THE SOUTH END OF THE LAKE. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WIND ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-ILZ011-
ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-ILZ023-
ILZ032-ILZ033-ILZ039 UNTIL 3 AM THURSDAY.
IN...WIND ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL 3 AM
THURSDAY.
LM...GALE WARNING...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-
LMZ779 UNTIL 9 PM WEDNESDAY.
GALE WARNING...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745...3 AM
THURSDAY TO 6 AM THURSDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 6 PM WEDNESDAY.
STORM WARNING...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-
LMZ779...9 PM WEDNESDAY TO 3 AM THURSDAY.
DENSE FOG ADVISORY...LMZ777-LMZ779 UNTIL 6 PM WEDNESDAY.
GALE WARNING...LMZ777-LMZ779...3 AM THURSDAY TO 9 AM THURSDAY.
&&
$$
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
405 PM CST WED DEC 23 2015
.MESOSCALE DISCUSSION...
242 PM CST
FIRST ROUND OF THUNDERSTORMS HAS PUSHED OFF TO THE EAST WITH
STRATIFORM RAIN IN PLACE ACROSS PORTIONS OF EAST CENTRAL ILLINOIS
AND NORTHWEST INDIANA. LOW PRESSURE IS ANALYZED JUST SOUTH OF
KDSM THIS AFTERNOON WITH A FRONTAL BOUNDARY STRETCHING SOUTH
ACROSS MISSOURI. VISIBLE SATELLITE IMAGERY SHOWS TOWERING CU AND A
FEW CB/S IMMEDIATELY AHEAD OF THE FRONT WHERE SURFACE TEMPS ARE IN
THE MID 60S AND DEWPOINTS IN THE LOW TO MID 50S. 18Z SPECIAL
SOUNDING OUT OF KDVN SHOWED AROUND 250 J/KG SBCAPE WITH FAIRLY
INTENSE DEEP LAYER SHEAR IN EXCESS OF 70KT. WATER VAPOR IMAGERY
SHOWS A DRY SLOT WRAPPING INTO NORTHEASTERN MISSOURI AND
SOUTHEASTERN COINCIDENT WITH THE CORRIDOR OF MODEST INSTABILITY OF
200-600 J/KG MLCAPE WHICH RAP GUIDANCE SHOWS LIFTING ACROSS
PORTIONS OF NORTH CENTRAL ILLINOIS WITHIN THE NEXT FEW HOURS.
STRONG PRESSURE FALLS AHEAD OF THE LOW MAY HELP TO KEEP WINDS
BACKED ACROSS NORTH CENTRAL ILLINOIS WHICH WILL LOCALLY ENHANCE
THE THREAT FOR SUPERCELLS ALONG WITH THE POSSIBILITY OF AN
ISOLATED TORNADO. A BIT HARD TO TELL HOW FAR EAST THE SEVERE
THREAT WILL EXTEND THIS AFTERNOON AND EVENING...THOUGH HI- RES
MODELS HAVE CONSISTENTLY SHOWED A WEAKENING TREND AS THUNDERSTORMS
APPROACH THE CHICAGO METRO AREA THIS EVENING. FOR NOW AM MOST
CONCERNED ABOUT SEVERE WEATHER WEST OF A PONTIAC TO WOODSTOCK
LINE...BUT CERTAINLY NOT OUT OF THE WOODS FARTHER EAST.
DEUBELBEISS
&&
.SHORT TERM...
236 PM CST
THROUGH THURSDAY...
A DEEP UPPER TROUGH IS OVER THE CENTRAL CONUS WITH A STRONG MID
LEVEL SHORTWAVE TRACKING NEWD THROUGH THE UPPER MISSOURI VALLEY. A
SERIES OF WEAKER SHORTWAVES HAVE BEEN TRACKING NEWD THROUGH THE
MIDDLE MISSISSIPPI VALLEY...GENERATING SCT STRONG THUNDERSTORMS AS
FAR NORTH AS NERN IL AND NWRN IN EARLIER TODAY. THE SRN STREAM
SHORTWAVE ENERGY IS BEGINNING TO FOCUS TSRA OVER THE LOWER OHIO
VALLEY AND INTO INDIANA THIS AFTERNOON AND THE MAIN AREA OF CONCERN
WITH RESPECT TO TSRA ACTIVITY FOR THE LOCAL AREA WILL BE UNDER THE
MID LEVEL CIRCULATION CENTER. UNDER THE COLD CORE UPPER LOW AND
WITH UNSEASONABLY WARM...MOIST AIR IN PLACE OVER THE REGION...STRONG
LAPSE RATES AND MODEST LOW LEVEL INSTABILITY WILL KEEP A CHANCE FOR
THUNDERSTORMS INTO THE EVENING HOURS. THE LATEST SATELLITE IMAGERY
SHOWS SOME BREAKS IN THE OVERCAST UNDER THE UPPER LOW WITH SOME
CONVECTIVE CLOUD DEVELOPMENT APPARENT. SOME OF THIS ACTIVITY IS
ALREADY GENERATING LIGHTNING OVER IOWA AND NERN MO. LATEST SPC
MESOSCALE ANALYSIS INDICATES AN AREA OF LOW LEVEL INSTABILITY
CONSISTENT WITH THE CURRENT CONVECTIVE DEVELOPMENT AND THE SHORT
RANGE HIGH RES MODEL GUIDANCE INDICATES THAT THERE IS A CHANCE FOR
THUNDERSTORM ACTIVITY TO MAINTAIN INTO THE EVENING HOURS...MOSTLY
ACROSS NRN IL. ALSO...MORNING SOUNDINGS INDICATE STRONG VERTICAL
SHEAR FROM THE SFC THROUGH MID LEVELS...SO LOW-TOPPED SUPERCELL
DEVELOPMENT REMAIN A POSSIBILITY STRONG...DAMAGING WIND...ISOLATED
LARGE HAIL AND A FEW TORNADOES WILL REMAIN A POSSIBILITY INTO THE
EVENING.
ANOTHER CONCERN FOR THE EVENING AND INTO THE OVERNIGHT HOURS WILL BE
STRONG SYNOPTIC SCALE WINDS. AS THE MAIN SFC LOW QUICKLY LIFTS NEWD
FROM ERN IOWA THIS AFTERNOON TO LAKE SUPERIOR WHILE DEEPENING AT
LEAST 10MB BY ARND 06Z...STRONG PRESSURE RISES IN THE WAKE OF THE
LOW WILL HELP GENERATE STRONG SLWY-WLY WINDS WITH SUSTAINED SPEEDS
ARND 30 MPH AND GUSTS OF 40-50 MPH. THE PERIOD OF THE STRONGEST
WINDS WILL BE FROM ARND 03-09Z WHICH WILL BE THE PERIOD OF THE
STRONGEST PRESSURE RISES.
FOR THURSDAY...CONDITIONS WILL BE MUCH QUIETER AS HIGH PRESSURE
BUILDS ACROSS THE REGION. EVEN WITH A STRONG COLD FRONT EXPECTED TO
MOVE ACROSS THE REGION AS THE SFC LOW LIFTS TO THE
NORTHEAST...TEMPERATURES WILL REMAIN ABOVE SEASONABLE NORMAL LEVELS
WITH HIGHS RANGING FROM AROUND 40F OVER THE ROCKFORD AREA TO THE
UPPER 40S SOUTH OF A VALPARAISO TO PONTIAC LINE.
KREIN
&&
.LONG TERM...
THURSDAY NIGHT THROUGH WEDNESDAY...
259 PM...TWO STORM SYSTEMS TO AFFECT THE REGION...FIRST SATURDAY
INTO SATURDAY NIGHT WITH HEAVY RAIN POSSIBLE ESPECIALLY ACROSS THE
SOUTHERN CWA. SECOND STORM SYSTEM MONDAY INTO TUESDAY...WITH
UNCERTAINTY REGARDING TIMING AND PRECIP TYPE.
HIGH PRESSURE WILL BE MOVING ACROSS THE AREA THURSDAY NIGHT INTO
FRIDAY WITH DRY CONDITIONS EXPECTED THROUGH FRIDAY EVENING. LIGHT
WINDS AND AT LEAST SOME PARTIAL CLEARING THURSDAY NIGHT SHOULD
ALLOW TEMPS TO DROP INTO THE UPPER 20S/LOWER 30S. HIGHS BACK IN
THE 40S ON CHRISTMAS DAY WITH INCREASING CLOUDS BY AFTERNOON/
EVENING AHEAD OF THE NEXT SYSTEM.
NEXT STORM SYSTEM BEGINS TO AFFECT THE AREA LATE FRIDAY NIGHT BUT
MORESO INTO SATURDAY WITH A COLD FRONT SLOWLY SAGGING THROUGH THE
AREA AND EVENTUALLY SOUTH OF THE AREA SATURDAY NIGHT. HOW FAST THIS
BOUNDARY SAGS SOUTH...OR ANY OTHER CHANGES TO ITS SPEED/LOCATION MAY
HAVE LARGE IMPACTS ON WHERE A BAND/CORRIDOR OF VERY HEAVY RAIN SETS
UP. CURRENTLY APPEARS TO BE ACROSS CENTRAL ILLINOIS INTO CENTRAL
INDIANA...INCLUDING THE FAR SOUTHEAST CWA. ITS POSSIBLE 1 TO 2
INCHES OF RAIN MAY FALL ACROSS THIS AREA THROUGH SATURDAY NIGHT
WITH AMOUNTS DECREASING ACROSS NORTHERN IL. THIS ADDITIONAL
RAINFALL MAY BOTH EXTEND CURRENT ELEVATED RIVER LEVELS AND CAUSE
POSSIBLE NEW RISES. THERMALLY...WHILE SURFACE WINDS SHIFT
NORTHERLY AND COOLER AIR SPREADS ACROSS THE REGION...IT APPEARS
THE BULK OF THIS PRECIP WILL FALL AS RAIN. HOWEVER...BY SUNDAY
MORNING...DEPENDING ON HOW MUCH PRECIP IS STILL OCCURRING...THERE
COULD BE A MIX WITH LIGHT SNOW. THOUGH PRECIP MAY END BEFORE IT
BECOMES COLD ENOUGH FOR A MIX WITH SNOW.
MAINTAINED LOW CHANCE POPS SUNDAY NIGHT BUT THIS TIME PERIOD IS ALSO
NOW LOOKING TO BE MAINLY DRY...WITH PERHAPS THE BEST CHANCE OF ANY
PRECIP ACROSS THE FAR SOUTHERN CWA AND TOWARD MONDAY MORNING. IF ANY
PRECIP DOES OCCUR SUNDAY NIGHT...THERE COULD BE SOME MIX OF SNOW OR
SLEET. WHILE THERE IS FAIR CONSISTENCY WITH PRECIP SPREADING BACK
ACROSS THE AREA MONDAY AND THEN PRECIP LIKELY MONDAY NIGHT...THE
TRACK OF THE LOW AND THUS THE EXTENT OF WARM AIR AND THEREFORE
PRECIP TYPE BECOMES QUITE UNCERTAIN. THE GEM/GFS ARE SIMILAR AND
COLDER WHILE THE ECMWF IS WARMER. A BLEND OF THESE SOLUTIONS IS IN
FAIR AGREEMENT WITH THE PREVIOUS FORECAST WHICH MAINTAINS A MIX OF
RAIN AND SNOW MONDAY AND MONDAY NIGHT. THERE IS SOME POTENTIAL FOR
SLEET AND PERHAPS FREEZING RAIN BUT GIVEN THE THERMAL
UNCERTAINTY... ITS TOO EARLY FOR DETAILS. HOWEVER...IF STRONG
PERSISTENT NORTHEAST WINDS DO DEVELOP...THIS WILL MAINTAIN A
DRIER...COOLER INFLOW AND ONCE PRECIP STARTS...EVAPORATIVE COOLING
MAY BE SUFFICIENT FOR AT LEAST A WINTERY MIX AND PERHAPS A PERIOD
OF SNOW. SMALL CHANGES IN THE TRACK WILL RESULT IN LARGE CHANGES
TO THE FORECAST.
COLDER AIR THEN APPEARS TO SPREAD BACK ACROSS THE AREA BY MID WEEK
NEXT WEEK WITH A WEAK DISTURBANCE THAT WILL LIKELY RESULT IN AT
LEAST A CHANCE OF LIGHT SNOW OR SNOW SHOWERS. CMS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 22Z...
* POTENTIAL FOR A FEW ADDITIONAL STRONG STORMS EARLY THIS EVENING
(01-03 UTC).
* STRONG GUSTY SOUTH WINDS 25-30 KT THIS AFTERNOON.
* POTENTIAL FOR VERY STRONG SOUTHWESTERLY WINDS FOR A SHORT PERIOD
THIS EVENING BETWEEN 03-06 UTC. GUSTS OF 45 TO 50 KT POSSIBLE
DURING THIS PERIOD.
KJB/RATZER
//DISCUSSION...UPDATED 18Z...
A SIGNIFICANT STORM SYSTEM WILL CONTINUE TO IMPACT THE REGION INTO
TONIGHT. THE MAIN AVIATION WEATHER CONCERNS WILL BE THE POTENTIAL
FOR ADDITIONAL SCT STRONG THUNDERSTORMS EARLY THIS EVENING...GUSTY
SOUTH WINDS THIS AFTERNOON...FOLLOWED BY A PERIOD OF VERY STRONG
GUSTY SYNOPTIC SOUTHWESTERLY WINDS LATER THIS EVENING.
CURRENTLY AN AREA OF MAINLY SHOWERS...WITH A FEW EMBEDDED
THUNDERSTORMS...CONTINUES TO MOVE ACROSS THE EASTERN AIRFIELDS AS A
WARM FRONT GRADUALLY SHIFTS NORTHWARD OVER THE AREA. THIS SHOWERS
ACTIVITY WILL BEGIN TO MOVE OUT OF THE AREA AROUND...OR SLIGHTLY
AFTER THE 19 UTC HOUR...WITH ONLY SOME WIDELY SCT SHOWERS POSSIBLE
THEREAFTER. CIGS AND VSBYS WILL ALSO BE IMPROVING THIS
AFTERNOON...THOUGH THE SURFACE WINDS WILL CONTINUE TO BECOME DUE
SOUTHERLY AND GUSTY...UP AROUND 30 KT THROUGH THE REST OF THE
AFTERNOON.
ANOTHER BATCH OF SCATTERED THUNDERSTORMS MAY DEVELOP VERY LATE THIS
AFTERNOON OVER WESTERN ILLINOIS AHEAD OF AN APPROACHING COLD FRONT.
THESE STORMS COULD THEN PROGRESS EAST-NORTHEASTWARD OVER THE EASTERN
TERMINALS EARLY THIS EVENING...ROUGHLY BETWEEN 00 AND 03 UTC THIS
EVENING. THE POTENTIAL FOR STORMS AT A GIVEN TERMINAL WILL LIKELY BE
FAIRLY SHORT (UNDER AN HOUR)...THOUGH EXACT TIMING REQUIRES A 2 HOUR
TEMPO AT THIS RANGE. THESE POTENTIAL STORMS ALSO HAVE A CONDITIONAL
RISK OF BEING SEVERE WITH STRONG SURFACE WINDS.
FOLLOWING THE COLD FRONTAL PASSAGE...AROUND 02-03 UTC THIS
EVENING...IT APPEARS THAT THE SURFACE WINDS OUTSIDE OF THUNDERSTORMS
COULD BECOME VERY STRONG FOR A SHORT PERIOD. VERY STRONG PRESSURE
RISES LOOK TO OVERSPREAD THE AREA BEHIND THIS FRONT...AND THIS COULD
LEAD TO VERY EFFICIENT TRANSPORT OF STRONGER WINDS ALOFT TO THE
SURFACE MID TO LATE THIS EVENING. WIND GUSTS COULD BRIEFLY GUST IN
THE 45 TO 50 KT RANGE DURING THIS PERIOD...BEFORE ABATING
OVERNIGHT.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 22Z...
* MEDIUM-HIGH WITH TSRA/TIMING THIS EVENING.
* MEDIUM HIGH WITH WIND FORECAST.
KJB/RATZER
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT...VFR.
FRIDAY...VFR.
SATURDAY...SHOWERS. CHANCE OF MVFR/IFR.
SUNDAY...CHANCE OF RAIN/SNOW/SLEET AND MVFR CIGS.
MONDAY...CHANCE OF RAIN/SNOW/SLEET AND MVFR CIGS.
TUESDAY...CHANCE OF RAIN/SNOW AND MVFR CIGS.
RODRIGUEZ
&&
.MARINE...
446 AM CST
SIGNIFICANT CHANGES MADE TO WINDS/WAVES FOR THIS FORECAST
PERIOD...WITH STORM FORCE WINDS AND GALES LIKELY ACROSS THE ENTIRE
LAKE LATER TODAY...TONIGHT...AND THURSDAY.
SOUTHEAST WINDS WILL CONTINUE TO INCREASE TODAY AS LOW PRESSURE OVER
THE CENTRAL PLAINS LIFTS NORTHEAST ACROSS THE REGION. EXPECT WINDS
TO REALLY RAMP UP THIS AFTERNOON...WITH TO 30KT WINDS BEING OBSERVED
ACROSS ALL OF THE LAKE. ALTHOUGH NOT OVERLY CONFIDENT...DO THINK
THERE WILL BE AT LEAST GALE FORCE GUSTS ACROSS THE NEARSHORE WATERS
AND SOUTH HALF OF THE LAKE THIS AFTERNOON...AND HAVE THAT INCLUDED
IN THE FORECAST. WINDS WILL FURTHER INCREASE TONIGHT WITH HIGH END
GALES TO 45 KT EXPECTED ACROSS THE SOUTH HALF AND NEARSHORE...AND
THEN STORM FORCE WINDS TO 50KT ACROSS THE NORTH HALF. THERE WILL
BE A POSSIBILITY FOR STORM FORCE WINDS ACROSS THE SOUTH HALF AND
NEARSHORE...BUT AT THIS TIME...THIS LOOKS TO BE ONLY FOR A SMALL
WINDOW. HOWEVER...WILL NEED TO MONITOR THE POTENTIAL FOR A LONGER
PERIOD OF POSSIBLE STORM FORCE WINDS IN THOSE LOCATIONS. WINDS
WILL BEGIN TO COME DOWN ON THURSDAY...BUT WITH STORM AND GALES
HOLDING ONTO A LITTLE LONGER ON THE NORTH HALF. HAVE GALES GOING
ACROSS THE NORTH INTO THE AFTERNOON...BUT THERE IS A POSSIBILITY
THAT THEY MAY CONTINUE EVEN INTO IN THE EVENING.
RODRIGUEZ
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WIND ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-ILZ011-
ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-ILZ023-
ILZ032-ILZ033-ILZ039 UNTIL 3 AM THURSDAY.
IN...WIND ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL 3 AM
THURSDAY.
LM...GALE WARNING...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-
LMZ779 UNTIL 9 PM WEDNESDAY.
GALE WARNING...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745...3 AM
THURSDAY TO 6 AM THURSDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 6 PM WEDNESDAY.
STORM WARNING...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-
LMZ779...9 PM WEDNESDAY TO 3 AM THURSDAY.
DENSE FOG ADVISORY...LMZ777-LMZ779 UNTIL 6 PM WEDNESDAY.
GALE WARNING...LMZ777-LMZ779...3 AM THURSDAY TO 9 AM THURSDAY.
&&
$$
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AREA FORECAST DISCUSSION
National Weather Service Lincoln IL
312 PM CST WED DEC 23 2015
.SHORT TERM...(Tonight)
ISSUED AT 312 PM CST WED DEC 23 2015
First round of severe weather has exited the eastern forecast area
early this afternoon, but storms have quickly started to fire in
northeast Missouri. This particular area has seen some sunshine
during the afternoon, helping to destabilize the atmosphere, where
CAPE`s are above 500 J/kg and 0-6km bulk shear is an impressive 60-
70 knots. HRRR latched onto this area of development earlier, and
races it across the northern part of the forecast area between 4 pm
and 8 pm. Have concentrated the highest PoP`s for the rest of the
afternoon in this area. The storms should be weakening after sunset
as the surface low pulls northeast, and there is some question about
how much the atmosphere across the eastern CWA can recover after
being thoroughly worked over the last several hours.
Secondary concern is with the winds this evening. Have issued a Wind
Advisory for the period from 6 pm to 2 am across about the northwest
half of the forecast area. Main surface low is currently located
across northeast Iowa, and will be zipping northeast. Impressive 3-
hour pressure rises of 10-11 mb are progged to track northeastward
to around Rockford by midnight. Wind gusts of 45 mph or so are
likely across the northwest half of the forecast area as this
bullseye passes. Have gone as far south as Jacksonville with the
advisory, but this area may be of a shorter duration. Most of the
winds should be diminishing around midnight, but will linger a bit
longer north of I-74.
&&
.LONG TERM...(Thursday through Wednesday)
ISSUED AT 312 PM CST WED DEC 23 2015
Short and medium range models are in fairly good agreement with the
overall active weather pattern through the weekend and into early
next week. Unseasonably warm temperatures and very wet weather will
be the main factors for the weekend through late Monday.
In the shorter term, mild temperatures and periods of cloudiness can
be expected for Christmas Eve into much of Christmas Day. The return
of a surface boundary north of the Ohio Valley and associated weak
isentropic lift initially will result in a chance for light rain in
southeast IL late on Christmas Day. The GFS is the odd model out on
this one by keeping the boundary much farther south.
Backing upper level flow in response to a digging trough in the
western U.S. will allow very warm and moist air to return into much
of central and SE IL during the day Saturday. This feed of moisture
and the associated rainfall will linger in the forecast area through
most of Sunday, resulting in 2.50 to 3.50 inches of rain. The
precipitation area will gradually sag south as the upper low in the
west closes off in SW Texas and an upper level confluent area sets
up across central IL by later in the day Sunday.
The upper low in the southwestern U.S. is expected to kick out
toward the Midwest Monday as another strong upper level trough digs
from the Pacific NW to the southern Plains. This will bring the
likelihood of precipitation back to central IL for Monday. The
forecast type becomes a bit tricky north of a Rushville-Bloomington
line Monday into Monday night as upper level soundings indicate a
mix of rain/snow/sleet possible. Could be some minor accumulations
of snow NW of Peoria late Monday, but there is a lot of uncertainty
with this scenario 6 days out.
&&
.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
ISSUED AT 1149 AM CST WED DEC 23 2015
Active convective weather with a complex weather system can be
expected in central and eastern IL this afternoon through this
evening. The majority of the area is in the warm sector of the
storm system, so ceilings have come up considerably due to this
and the high winds from the mixing of the lower atmosphere.
Several rounds of showers/t-storms will impact central and eastern
IL TAF sites through at least 20-21 UTC before the next round
approaches/develops in the 21-03 UTC timeframe. Added a TEMPO
group to not only highlight the MVFR visibility/ceilings from the
moderate to heavy rain, but also wind gusts exceeding 40 kts from
the strongest thunderstorms.
Outside of the thunderstorms, VFR conditions are anticipated.
However, an increasing pressure gradient this afternoon through
the evening will result in south to southwest winds of 25-30 kts
with gusts around 35 kts.
The sky is expected to partially clear and wind settle down a bit
after midnight local time. Increasing mid level clouds are
anticipated by mid-morning Thursday, but conditions will be VFR.
&&
.ILX Watches/Warnings/Advisories...
Wind Advisory until 2 AM CST Thursday for ILZ027>031-036>038-
040>043-047>050.
&&
$$
SHORT TERM...Geelhart
LONG TERM...Miller
AVIATION...Miller
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
259 PM CST WED DEC 23 2015
.MESOSCALE DISCUSSION...
242 PM CST
FIRST ROUND OF THUNDERSTORMS HAS PUSHED OFF TO THE EAST WITH
STRATIFORM RAIN IN PLACE ACROSS PORTIONS OF EAST CENTRAL ILLINOIS
AND NORTHWEST INDIANA. LOW PRESSURE IS ANALYZED JUST SOUTH OF
KDSM THIS AFTERNOON WITH A FRONTAL BOUNDARY STRETCHING SOUTH
ACROSS MISSOURI. VISIBLE SATELLITE IMAGERY SHOWS TOWERING CU AND A
FEW CB/S IMMEDIATELY AHEAD OF THE FRONT WHERE SURFACE TEMPS ARE IN
THE MID 60S AND DEWPOINTS IN THE LOW TO MID 50S. 18Z SPECIAL
SOUNDING OUT OF KDVN SHOWED AROUND 250 J/KG SBCAPE WITH FAIRLY
INTENSE DEEP LAYER SHEAR IN EXCESS OF 70KT. WATER VAPOR IMAGERY
SHOWS A DRY SLOT WRAPPING INTO NORTHEASTERN MISSOURI AND
SOUTHEASTERN COINCIDENT WITH THE CORRIDOR OF MODEST INSTABILITY OF
200-600 J/KG MLCAPE WHICH RAP GUIDANCE SHOWS LIFTING ACROSS
PORTIONS OF NORTH CENTRAL ILLINOIS WITHIN THE NEXT FEW HOURS.
STRONG PRESSURE FALLS AHEAD OF THE LOW MAY HELP TO KEEP WINDS
BACKED ACROSS NORTH CENTRAL ILLINOIS WHICH WILL LOCALLY ENHANCE
THE THREAT FOR SUPERCELLS ALONG WITH THE POSSIBILITY OF AN
ISOLATED TORNADO. A BIT HARD TO TELL HOW FAR EAST THE SEVERE
THREAT WILL EXTEND THIS AFTERNOON AND EVENING...THOUGH HI- RES
MODELS HAVE CONSISTENTLY SHOWED A WEAKENING TREND AS THUNDERSTORMS
APPROACH THE CHICAGO METRO AREA THIS EVENING. FOR NOW AM MOST
CONCERNED ABOUT SEVERE WEATHER WEST OF A PONTIAC TO WOODSTOCK
LINE...BUT CERTAINLY NOT OUT OF THE WOODS FARTHER EAST.
DEUBELBEISS
&&
.SHORT TERM...
236 PM CST
THROUGH THURSDAY...
A DEEP UPPER TROUGH IS OVER THE CENTRAL CONUS WITH A STRONG MID
LEVEL SHORTWAVE TRACKING NEWD THROUGH THE UPPER MISSOURI VALLEY. A
SERIES OF WEAKER SHORTWAVES HAVE BEEN TRACKING NEWD THROUGH THE
MIDDLE MISSISSIPPI VALLEY...GENERATING SCT STRONG THUNDERSTORMS AS
FAR NORTH AS NERN IL AND NWRN IN EARLIER TODAY. THE SRN STREAM
SHORTWAVE ENERGY IS BEGINNING TO FOCUS TSRA OVER THE LOWER OHIO
VALLEY AND INTO INDIANA THIS AFTERNOON AND THE MAIN AREA OF CONCERN
WITH RESPECT TO TSRA ACTIVITY FOR THE LOCAL AREA WILL BE UNDER THE
MID LEVEL CIRCULATION CENTER. UNDER THE COLD CORE UPPER LOW AND
WITH UNSEASONABLY WARM...MOIST AIR IN PLACE OVER THE REGION...STRONG
LAPSE RATES AND MODEST LOW LEVEL INSTABILITY WILL KEEP A CHANCE FOR
THUNDERSTORMS INTO THE EVENING HOURS. THE LATEST SATELLITE IMAGERY
SHOWS SOME BREAKS IN THE OVERCAST UNDER THE UPPER LOW WITH SOME
CONVECTIVE CLOUD DEVELOPMENT APPARENT. SOME OF THIS ACTIVITY IS
ALREADY GENERATING LIGHTNING OVER IOWA AND NERN MO. LATEST SPC
MESOSCALE ANALYSIS INDICATES AN AREA OF LOW LEVEL INSTABILITY
CONSISTENT WITH THE CURRENT CONVECTIVE DEVELOPMENT AND THE SHORT
RANGE HIGH RES MODEL GUIDANCE INDICATES THAT THERE IS A CHANCE FOR
THUNDERSTORM ACTIVITY TO MAINTAIN INTO THE EVENING HOURS...MOSTLY
ACROSS NRN IL. ALSO...MORNING SOUNDINGS INDICATE STRONG VERTICAL
SHEAR FROM THE SFC THROUGH MID LEVELS...SO LOW-TOPPED SUPERCELL
DEVELOPMENT REMAIN A POSSIBILITY STRONG...DAMAGING WIND...ISOLATED
LARGE HAIL AND A FEW TORNADOES WILL REMAIN A POSSIBILITY INTO THE
EVENING.
ANOTHER CONCERN FOR THE EVENING AND INTO THE OVERNIGHT HOURS WILL BE
STRONG SYNOPTIC SCALE WINDS. AS THE MAIN SFC LOW QUICKLY LIFTS NEWD
FROM ERN IOWA THIS AFTERNOON TO LAKE SUPERIOR WHILE DEEPENING AT
LEAST 10MB BY ARND 06Z...STRONG PRESSURE RISES IN THE WAKE OF THE
LOW WILL HELP GENERATE STRONG SLWY-WLY WINDS WITH SUSTAINED SPEEDS
ARND 30 MPH AND GUSTS OF 40-50 MPH. THE PERIOD OF THE STRONGEST
WINDS WILL BE FROM ARND 03-09Z WHICH WILL BE THE PERIOD OF THE
STRONGEST PRESSURE RISES.
FOR THURSDAY...CONDITIONS WILL BE MUCH QUIETER AS HIGH PRESSURE
BUILDS ACROSS THE REGION. EVEN WITH A STRONG COLD FRONT EXPECTED TO
MOVE ACROSS THE REGION AS THE SFC LOW LIFTS TO THE
NORTHEAST...TEMPERATURES WILL REMAIN ABOVE SEASONABLE NORMAL LEVELS
WITH HIGHS RANGING FROM AROUND 40F OVER THE ROCKFORD AREA TO THE
UPPER 40S SOUTH OF A VALPARAISO TO PONTIAC LINE.
KREIN
&&
.LONG TERM...
THURSDAY NIGHT THROUGH WEDNESDAY...
259 PM...TWO STORM SYSTEMS TO AFFECT THE REGION...FIRST SATURDAY
INTO SATURDAY NIGHT WITH HEAVY RAIN POSSIBLE ESPECIALLY ACROSS THE
SOUTHERN CWA. SECOND STORM SYSTEM MONDAY INTO TUESDAY...WITH
UNCERTAINTY REGARDING TIMING AND PRECIP TYPE.
HIGH PRESSURE WILL BE MOVING ACROSS THE AREA THURSDAY NIGHT INTO
FRIDAY WITH DRY CONDITIONS EXPECTED THROUGH FRIDAY EVENING. LIGHT
WINDS AND AT LEAST SOME PARTIAL CLEARING THURSDAY NIGHT SHOULD
ALLOW TEMPS TO DROP INTO THE UPPER 20S/LOWER 30S. HIGHS BACK IN
THE 40S ON CHRISTMAS DAY WITH INCREASING CLOUDS BY AFTERNOON/
EVENING AHEAD OF THE NEXT SYSTEM.
NEXT STORM SYSTEM BEGINS TO AFFECT THE AREA LATE FRIDAY NIGHT BUT
MORESO INTO SATURDAY WITH A COLD FRONT SLOWLY SAGGING THROUGH THE
AREA AND EVENTUALLY SOUTH OF THE AREA SATURDAY NIGHT. HOW FAST THIS
BOUNDARY SAGS SOUTH...OR ANY OTHER CHANGES TO ITS SPEED/LOCATION MAY
HAVE LARGE IMPACTS ON WHERE A BAND/CORRIDOR OF VERY HEAVY RAIN SETS
UP. CURRENTLY APPEARS TO BE ACROSS CENTRAL ILLINOIS INTO CENTRAL
INDIANA...INCLUDING THE FAR SOUTHEAST CWA. ITS POSSIBLE 1 TO 2
INCHES OF RAIN MAY FALL ACROSS THIS AREA THROUGH SATURDAY NIGHT
WITH AMOUNTS DECREASING ACROSS NORTHERN IL. THIS ADDITIONAL
RAINFALL MAY BOTH EXTEND CURRENT ELEVATED RIVER LEVELS AND CAUSE
POSSIBLE NEW RISES. THERMALLY...WHILE SURFACE WINDS SHIFT
NORTHERLY AND COOLER AIR SPREADS ACROSS THE REGION...IT APPEARS
THE BULK OF THIS PRECIP WILL FALL AS RAIN. HOWEVER...BY SUNDAY
MORNING...DEPENDING ON HOW MUCH PRECIP IS STILL OCCURRING...THERE
COULD BE A MIX WITH LIGHT SNOW. THOUGH PRECIP MAY END BEFORE IT
BECOMES COLD ENOUGH FOR A MIX WITH SNOW.
MAINTAINED LOW CHANCE POPS SUNDAY NIGHT BUT THIS TIME PERIOD IS ALSO
NOW LOOKING TO BE MAINLY DRY...WITH PERHAPS THE BEST CHANCE OF ANY
PRECIP ACROSS THE FAR SOUTHERN CWA AND TOWARD MONDAY MORNING. IF ANY
PRECIP DOES OCCUR SUNDAY NIGHT...THERE COULD BE SOME MIX OF SNOW OR
SLEET. WHILE THERE IS FAIR CONSISTENCY WITH PRECIP SPREADING BACK
ACROSS THE AREA MONDAY AND THEN PRECIP LIKELY MONDAY NIGHT...THE
TRACK OF THE LOW AND THUS THE EXTENT OF WARM AIR AND THEREFORE
PRECIP TYPE BECOMES QUITE UNCERTAIN. THE GEM/GFS ARE SIMILAR AND
COLDER WHILE THE ECMWF IS WARMER. A BLEND OF THESE SOLUTIONS IS IN
FAIR AGREEMENT WITH THE PREVIOUS FORECAST WHICH MAINTAINS A MIX OF
RAIN AND SNOW MONDAY AND MONDAY NIGHT. THERE IS SOME POTENTIAL FOR
SLEET AND PERHAPS FREEZING RAIN BUT GIVEN THE THERMAL
UNCERTAINTY... ITS TOO EARLY FOR DETAILS. HOWEVER...IF STRONG
PERSISTENT NORTHEAST WINDS DO DEVELOP...THIS WILL MAINTAIN A
DRIER...COOLER INFLOW AND ONCE PRECIP STARTS...EVAPORATIVE COOLING
MAY BE SUFFICIENT FOR AT LEAST A WINTERY MIX AND PERHAPS A PERIOD
OF SNOW. SMALL CHANGES IN THE TRACK WILL RESULT IN LARGE CHANGES
TO THE FORECAST.
COLDER AIR THEN APPEARS TO SPREAD BACK ACROSS THE AREA BY MID WEEK
NEXT WEEK WITH A WEAK DISTURBANCE THAT WILL LIKELY RESULT IN AT
LEAST A CHANCE OF LIGHT SNOW OR SNOW SHOWERS. CMS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* POTENTIAL FOR A FEW ADDITIONAL STRONG STORMS EARLY THIS EVENING
(01-03 UTC).
* INCREASING SOUTHERLY WINDS THIS AFTERNOON.
* POTENTIAL FOR VERY STRONG SOUTHWESTERLY WINDS FOR A SHORT PERIOD
THIS EVENING BETWEEN 03-06 UTC. GUSTS OF 45 TO 50 KT POSSIBLE
DURING THIS PERIOD.
KJB
//DISCUSSION...UPDATED 18Z...
A SIGNIFICANT STORM SYSTEM WILL CONTINUE TO IMPACT THE REGION INTO
TONIGHT. THE MAIN AVIATION WEATHER CONCERNS WILL BE THE POTENTIAL
FOR ADDITIONAL SCT STRONG THUNDERSTORMS EARLY THIS EVENING...GUSTY
SOUTH WINDS THIS AFTERNOON...FOLLOWED BY A PERIOD OF VERY STRONG
GUSTY SYNOPTIC SOUTHWESTERLY WINDS LATER THIS EVENING.
CURRENTLY AN AREA OF MAINLY SHOWERS...WITH A FEW EMBEDDED
THUNDERSTORMS...CONTINUES TO MOVE ACROSS THE EASTERN AIRFIELDS AS A
WARM FRONT GRADUALLY SHIFTS NORTHWARD OVER THE AREA. THIS SHOWERS
ACTIVITY WILL BEGIN TO MOVE OUT OF THE AREA AROUND...OR SLIGHTLY
AFTER THE 19 UTC HOUR...WITH ONLY SOME WIDELY SCT SHOWERS POSSIBLE
THEREAFTER. CIGS AND VSBYS WILL ALSO BE IMPROVING THIS
AFTERNOON...THOUGH THE SURFACE WINDS WILL CONTINUE TO BECOME DUE
SOUTHERLY AND GUSTY...UP AROUND 30 KT THROUGH THE REST OF THE
AFTERNOON.
ANOTHER BATCH OF SCATTERED THUNDERSTORMS MAY DEVELOP VERY LATE THIS
AFTERNOON OVER WESTERN ILLINOIS AHEAD OF AN APPROACHING COLD FRONT.
THESE STORMS COULD THEN PROGRESS EAST-NORTHEASTWARD OVER THE EASTERN
TERMINALS EARLY THIS EVENING...ROUGHLY BETWEEN 00 AND 03 UTC THIS
EVENING. THE POTENTIAL FOR STORMS AT A GIVEN TERMINAL WILL LIKELY BE
FAIRLY SHORT (UNDER AN HOUR)...THOUGH EXACT TIMING REQUIRES A 2 HOUR
TEMPO AT THIS RANGE. THESE POTENTIAL STORMS ALSO HAVE A CONDITIONAL
RISK OF BEING SEVERE WITH STRONG SURFACE WINDS.
FOLLOWING THE COLD FRONTAL PASSAGE...AROUND 02-03 UTC THIS
EVENING...IT APPEARS THAT THE SURFACE WINDS OUTSIDE OF THUNDERSTORMS
COULD BECOME VERY STRONG FOR A SHORT PERIOD. VERY STRONG PRESSURE
RISES LOOK TO OVERSPREAD THE AREA BEHIND THIS FRONT...AND THIS COULD
LEAD TO VERY EFFICIENT TRANSPORT OF STRONGER WINDS ALOFT TO THE
SURFACE MID TO LATE THIS EVENING. WIND GUSTS COULD BRIEFLY GUST IN
THE 45 TO 50 KT RANGE DURING THIS PERIOD...BEFORE ABATING
OVERNIGHT.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* MEDIUM WITH TSRA/TIMING THIS EVENING.
* MEDIUM HIGH WITH WIND FORECAST.
KJB
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT...VFR.
FRIDAY...VFR.
SATURDAY...SHOWERS. CHANCE OF MVFR/IFR.
SUNDAY...CHANCE OF RAIN/SNOW/SLEET AND MVFR CIGS.
MONDAY...CHANCE OF RAIN/SNOW/SLEET AND MVFR CIGS.
TUESDAY...CHANCE OF RAIN/SNOW AND MVFR CIGS.
RODRIGUEZ
&&
.MARINE...
446 AM CST
SIGNIFICANT CHANGES MADE TO WINDS/WAVES FOR THIS FORECAST
PERIOD...WITH STORM FORCE WINDS AND GALES LIKELY ACROSS THE ENTIRE
LAKE LATER TODAY...TONIGHT...AND THURSDAY.
SOUTHEAST WINDS WILL CONTINUE TO INCREASE TODAY AS LOW PRESSURE OVER
THE CENTRAL PLAINS LIFTS NORTHEAST ACROSS THE REGION. EXPECT WINDS
TO REALLY RAMP UP THIS AFTERNOON...WITH TO 30KT WINDS BEING OBSERVED
ACROSS ALL OF THE LAKE. ALTHOUGH NOT OVERLY CONFIDENT...DO THINK
THERE WILL BE AT LEAST GALE FORCE GUSTS ACROSS THE NEARSHORE WATERS
AND SOUTH HALF OF THE LAKE THIS AFTERNOON...AND HAVE THAT INCLUDED
IN THE FORECAST. WINDS WILL FURTHER INCREASE TONIGHT WITH HIGH END
GALES TO 45 KT EXPECTED ACROSS THE SOUTH HALF AND NEARSHORE...AND
THEN STORM FORCE WINDS TO 50KT ACROSS THE NORTH HALF. THERE WILL
BE A POSSIBILITY FOR STORM FORCE WINDS ACROSS THE SOUTH HALF AND
NEARSHORE...BUT AT THIS TIME...THIS LOOKS TO BE ONLY FOR A SMALL
WINDOW. HOWEVER...WILL NEED TO MONITOR THE POTENTIAL FOR A LONGER
PERIOD OF POSSIBLE STORM FORCE WINDS IN THOSE LOCATIONS. WINDS
WILL BEGIN TO COME DOWN ON THURSDAY...BUT WITH STORM AND GALES
HOLDING ONTO A LITTLE LONGER ON THE NORTH HALF. HAVE GALES GOING
ACROSS THE NORTH INTO THE AFTERNOON...BUT THERE IS A POSSIBILITY
THAT THEY MAY CONTINUE EVEN INTO IN THE EVENING.
RODRIGUEZ
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WIND ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-ILZ011-
ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-ILZ023-
ILZ032-ILZ033-ILZ039...6 PM WEDNESDAY TO 3 AM THURSDAY.
IN...WIND ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019...6 PM
WEDNESDAY TO 3 AM THURSDAY.
LM...GALE WARNING...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-
LMZ779...6 PM WEDNESDAY TO 9 PM WEDNESDAY.
GALE WARNING...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745...3 AM
THURSDAY TO 6 AM THURSDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 6 PM WEDNESDAY.
STORM WARNING...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-
LMZ779...9 PM WEDNESDAY TO 3 AM THURSDAY.
DENSE FOG ADVISORY...LMZ777-LMZ779 UNTIL 6 PM WEDNESDAY.
GALE WARNING...LMZ777-LMZ779...3 AM THURSDAY TO 9 AM THURSDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
242 PM CST WED DEC 23 2015
.MESOSCALE DISCUSSION...
242 PM CST
FIRST ROUND OF THUNDERSTORMS HAS PUSHED OFF TO THE EAST WITH
STRATIFORM RAIN IN PLACE ACROSS PORTIONS OF EAST CENTRAL ILLINOIS
AND NORTHWEST INDIANA. LOW PRESSURE IS ANALYZED JUST SOUTH OF
KDSM THIS AFTERNOON WITH A FRONTAL BOUNDARY STRETCHING SOUTH
ACROSS MISSOURI. VISIBLE SATELLITE IMAGERY SHOWS TOWERING CU AND A
FEW CB/S IMMEDIATELY AHEAD OF THE FRONT WHERE SURFACE TEMPS ARE IN
THE MID 60S AND DEWPOINTS IN THE LOW TO MID 50S. 18Z SPECIAL
SOUNDING OUT OF KDVN SHOWED AROUND 250 J/KG SBCAPE WITH FAIRLY
INTENSE DEEP LAYER SHEAR IN EXCESS OF 70KT. WATER VAPOR IMAGERY
SHOWS A DRY SLOT WRAPPING INTO NORTHEASTERN MISSOURI AND
SOUTHEASTERN COINCIDENT WITH THE CORRIDOR OF MODEST INSTABILITY OF
200-600 J/KG MLCAPE WHICH RAP GUIDANCE SHOWS LIFTING ACROSS
PORTIONS OF NORTH CENTRAL ILLINOIS WITHIN THE NEXT FEW HOURS.
STRONG PRESSURE FALLS AHEAD OF THE LOW MAY HELP TO KEEP WINDS
BACKED ACROSS NORTH CENTRAL ILLINOIS WHICH WILL LOCALLY ENHANCE
THE THREAT FOR SUPERCELLS ALONG WITH THE POSSIBILITY OF AN
ISOLATED TORNADO. A BIT HARD TO TELL HOW FAR EAST THE SEVERE
THREAT WILL EXTEND THIS AFTERNOON AND EVENING...THOUGH HI- RES
MODELS HAVE CONSISTENTLY SHOWED A WEAKENING TREND AS THUNDERSTORMS
APPROACH THE CHICAGO METRO AREA THIS EVENING. FOR NOW AM MOST
CONCERNED ABOUT SEVERE WEATHER WEST OF A PONTIAC TO WOODSTOCK
LINE...BUT CERTAINLY NOT OUT OF THE WOODS FARTHER EAST.
DEUBELBEISS
&&
.SHORT TERM...
236 PM CST
THROUGH THURSDAY...
A DEEP UPPER TROUGH IS OVER THE CENTRAL CONUS WITH A STRONG MID
LEVEL SHORTWAVE TRACKING NEWD THROUGH THE UPPER MISSOURI VALLEY. A
SERIES OF WEAKER SHORTWAVES HAVE BEEN TRACKING NEWD THROUGH THE
MIDDLE MISSISSIPPI VALLEY...GENERATING SCT STRONG THUNDERSTORMS AS
FAR NORTH AS NERN IL AND NWRN IN EARLIER TODAY. THE SRN STREAM
SHORTWAVE ENERGY IS BEGINNING TO FOCUS TSRA OVER THE LOWER OHIO
VALLEY AND INTO INDIANA THIS AFTERNOON AND THE MAIN AREA OF CONCERN
WITH RESPECT TO TSRA ACTIVITY FOR THE LOCAL AREA WILL BE UNDER THE
MID LEVEL CIRCULATION CENTER. UNDER THE COLD CORE UPPER LOW AND
WITH UNSEASONABLY WARM...MOIST AIR IN PLACE OVER THE REGION...STRONG
LAPSE RATES AND MODEST LOW LEVEL INSTABILITY WILL KEEP A CHANCE FOR
THUNDERSTORMS INTO THE EVENING HOURS. THE LATEST SATELLITE IMAGERY
SHOWS SOME BREAKS IN THE OVERCAST UNDER THE UPPER LOW WITH SOME
CONVECTIVE CLOUD DEVELOPMENT APPARENT. SOME OF THIS ACTIVITY IS
ALREADY GENERATING LIGHTNING OVER IOWA AND NERN MO. LATEST SPC
MESOSCALE ANALYSIS INDICATES AN AREA OF LOW LEVEL INSTABILITY
CONSISTENT WITH THE CURRENT CONVECTIVE DEVELOPMENT AND THE SHORT
RANGE HIGH RES MODEL GUIDANCE INDICATES THAT THERE IS A CHANCE FOR
THUNDERSTORM ACTIVITY TO MAINTAIN INTO THE EVENING HOURS...MOSTLY
ACROSS NRN IL. ALSO...MORNING SOUNDINGS INDICATE STRONG VERTICAL
SHEAR FROM THE SFC THROUGH MID LEVELS...SO LOW-TOPPED SUPERCELL
DEVELOPMENT REMAIN A POSSIBILITY STRONG...DAMAGING WIND...ISOLATED
LARGE HAIL AND A FEW TORNADOES WILL REMAIN A POSSIBILITY INTO THE
EVENING.
ANOTHER CONCERN FOR THE EVENING AND INTO THE OVERNIGHT HOURS WILL BE
STRONG SYNOPTIC SCALE WINDS. AS THE MAIN SFC LOW QUICKLY LIFTS NEWD
FROM ERN IOWA THIS AFTERNOON TO LAKE SUPERIOR WHILE DEEPENING AT
LEAST 10MB BY ARND 06Z...STRONG PRESSURE RISES IN THE WAKE OF THE
LOW WILL HELP GENERATE STRONG SLWY-WLY WINDS WITH SUSTAINED SPEEDS
ARND 30 MPH AND GUSTS OF 40-50 MPH. THE PERIOD OF THE STRONGEST
WINDS WILL BE FROM ARND 03-09Z WHICH WILL BE THE PERIOD OF THE
STRONGEST PRESSURE RISES.
FOR THURSDAY...CONDITIONS WILL BE MUCH QUIETER AS HIGH PRESSURE
BUILDS ACROSS THE REGION. EVEN WITH A STRONG COLD FRONT EXPECTED TO
MOVE ACROSS THE REGION AS THE SFC LOW LIFTS TO THE
NORTHEAST...TEMPERATURES WILL REMAIN ABOVE SEASONABLE NORMAL LEVELS
WITH HIGHS RANGING FROM AROUND 40F OVER THE ROCKFORD AREA TO THE
UPPER 40S SOUTH OF A VALPARAISO TO PONTIAC LINE.
KREIN
&&
.LONG TERM...
316 AM CST
THURSDAY THROUGH TUESDAY...
THURSDAY THROUGH FRIDAY...
ANTI-CYCLONIC FLOW QUICKLY ARRIVES EARLY THUR IN THE WAKE OF THE
DEPARTING TROUGH. THE 500MB PATTERN DOES BECOME QUASI-ZONAL FOR
THUR/FRI...WHICH WILL HELP TO KEEP TEMPS STILL SEVERAL DEGREES
ABOVE CLIMO IN THE LOW/MID 40S CHRISTMAS DAYAND POSSIBLY UPR 40S
FRI. DESPITE THE SFC RIDGE SLIDING OVERHEAD CHRISTMAS DAY...SKIES
WILL AT BEST BECOME P-CLOUDY IN THE AFTERNOON. THE DRY WEATHER
WILL ONLY BE SHORT-LIVED THROUGH FRI...AS THE ACTIVE PATTERN
BEGINS TO RAMP BACK-UP AS A TROUGH DIGS INTO THE FOUR- CORNERS
REGION OF THE CONUS. A QUASI-STATIONARY BOUNDARY WILL DEVELOP
ALONG THE TENN VALLEY FRI AFTN...AND WILL BECOME THE FOCUS FOR OUR
WEEKEND.
SATURDAY THROUGH TUESDAY... ENSEMBLES CONTINUE TO HOLD THE HIGH
AMPLITUDE RIDGE ALONG THE EASTERN CONUS WITH THE AFOREMENTIONED
TROUGH REMAINING ACROSS THE SOUTHERN ROCKIES/SOUTHWEST CONUS SAT.
OPERATIONAL GUIDANCE HAS BEEN IN GOOD AGREEMENT WITH A VORT MAX
EJECTING FROM THE TROUGH SAT WITH A SHORTWAVE DEVELOPING ALONG THE
SOUTHERN PLAINS. THIS FEATURE IS PROGGED TO ENERGIZE THE QUASI-
STATIONARY BOUNDARY AND LIFT NORTH. SIMULTANEOUSLY A SFC RIDGE IS
PROGGED TO DROP SOUTH FROM CENTRAL CANADA AND COVER MUCH OF THE
UPPER MIDWEST. THE INITIAL WAVE WILL BRING PRECIP BACK TO THE AREA
SAT/SAT NGT...THEN STRONG SFC RIDGE ACROSS THE HIGH PLAINS WILL
STEER THE BOUNDARY BACK SOUTH SUN.
THE MAIN CONCERN WILL BE ON THE DIRECTION AND STRENGTH OF THE
CANADIAN SFC RIDGE OVER THE NORTHERN PLAINS. GUIDANCE INDICATES THIS
FEATURE WILL SLIDE EAST AND COULD DEVELOP A SHARP BAROCLINIC ZONE
ACROSS THE GREAT LAKES REGION. WITH WINDS TURNING NORTHEAST AND A
BOUNDARY LIFTING BACK NORTH SUN NGT/MON...P-TYPE CONCERNS COULD BE
INTRODUCED BEFORE TEMPS WARM ENOUGH.
TEMPS SAT WILL WARM BACK INTO THE UPR 40S TO LOW 50S...THEN WITH THE
BOUNDARY SLIDING SOUTH SUN HIGHS WILL REMAIN IN THE UPR 30S TO LOW
40S. THEN FOR THE REMAINDER OF THE EXTENDED TEMPS COULD TREND BACK
TOWARDS THE MID/UPR 30S.
BEACHLER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* POTENTIAL FOR A FEW ADDITIONAL STRONG STORMS EARLY THIS EVENING
(01-03 UTC).
* INCREASING SOUTHERLY WINDS THIS AFTERNOON.
* POTENTIAL FOR VERY STRONG SOUTHWESTERLY WINDS FOR A SHORT PERIOD
THIS EVENING BETWEEN 03-06 UTC. GUSTS OF 45 TO 50 KT POSSIBLE
DURING THIS PERIOD.
KJB
//DISCUSSION...UPDATED 18Z...
A SIGNIFICANT STORM SYSTEM WILL CONTINUE TO IMPACT THE REGION INTO
TONIGHT. THE MAIN AVIATION WEATHER CONCERNS WILL BE THE POTENTIAL
FOR ADDITIONAL SCT STRONG THUNDERSTORMS EARLY THIS EVENING...GUSTY
SOUTH WINDS THIS AFTERNOON...FOLLOWED BY A PERIOD OF VERY STRONG
GUSTY SYNOPTIC SOUTHWESTERLY WINDS LATER THIS EVENING.
CURRENTLY AN AREA OF MAINLY SHOWERS...WITH A FEW EMBEDDED
THUNDERSTORMS...CONTINUES TO MOVE ACROSS THE EASTERN AIRFIELDS AS A
WARM FRONT GRADUALLY SHIFTS NORTHWARD OVER THE AREA. THIS SHOWERS
ACTIVITY WILL BEGIN TO MOVE OUT OF THE AREA AROUND...OR SLIGHTLY
AFTER THE 19 UTC HOUR...WITH ONLY SOME WIDELY SCT SHOWERS POSSIBLE
THEREAFTER. CIGS AND VSBYS WILL ALSO BE IMPROVING THIS
AFTERNOON...THOUGH THE SURFACE WINDS WILL CONTINUE TO BECOME DUE
SOUTHERLY AND GUSTY...UP AROUND 30 KT THROUGH THE REST OF THE
AFTERNOON.
ANOTHER BATCH OF SCATTERED THUNDERSTORMS MAY DEVELOP VERY LATE THIS
AFTERNOON OVER WESTERN ILLINOIS AHEAD OF AN APPROACHING COLD FRONT.
THESE STORMS COULD THEN PROGRESS EAST-NORTHEASTWARD OVER THE EASTERN
TERMINALS EARLY THIS EVENING...ROUGHLY BETWEEN 00 AND 03 UTC THIS
EVENING. THE POTENTIAL FOR STORMS AT A GIVEN TERMINAL WILL LIKELY BE
FAIRLY SHORT (UNDER AN HOUR)...THOUGH EXACT TIMING REQUIRES A 2 HOUR
TEMPO AT THIS RANGE. THESE POTENTIAL STORMS ALSO HAVE A CONDITIONAL
RISK OF BEING SEVERE WITH STRONG SURFACE WINDS.
FOLLOWING THE COLD FRONTAL PASSAGE...AROUND 02-03 UTC THIS
EVENING...IT APPEARS THAT THE SURFACE WINDS OUTSIDE OF THUNDERSTORMS
COULD BECOME VERY STRONG FOR A SHORT PERIOD. VERY STRONG PRESSURE
RISES LOOK TO OVERSPREAD THE AREA BEHIND THIS FRONT...AND THIS COULD
LEAD TO VERY EFFICIENT TRANSPORT OF STRONGER WINDS ALOFT TO THE
SURFACE MID TO LATE THIS EVENING. WIND GUSTS COULD BRIEFLY GUST IN
THE 45 TO 50 KT RANGE DURING THIS PERIOD...BEFORE ABATING
OVERNIGHT.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* MEDIUM WITH TSRA/TIMING THIS EVENING.
* MEDIUM HIGH WITH WIND FORECAST.
KJB
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT...VFR.
FRIDAY...VFR.
SATURDAY...SHOWERS. CHANCE OF MVFR/IFR.
SUNDAY...CHANCE OF RAIN/SNOW/SLEET AND MVFR CIGS.
MONDAY...CHANCE OF RAIN/SNOW/SLEET AND MVFR CIGS.
TUESDAY...CHANCE OF RAIN/SNOW AND MVFR CIGS.
RODRIGUEZ
&&
.MARINE...
446 AM CST
SIGNIFICANT CHANGES MADE TO WINDS/WAVES FOR THIS FORECAST
PERIOD...WITH STORM FORCE WINDS AND GALES LIKELY ACROSS THE ENTIRE
LAKE LATER TODAY...TONIGHT...AND THURSDAY.
SOUTHEAST WINDS WILL CONTINUE TO INCREASE TODAY AS LOW PRESSURE OVER
THE CENTRAL PLAINS LIFTS NORTHEAST ACROSS THE REGION. EXPECT WINDS
TO REALLY RAMP UP THIS AFTERNOON...WITH TO 30KT WINDS BEING OBSERVED
ACROSS ALL OF THE LAKE. ALTHOUGH NOT OVERLY CONFIDENT...DO THINK
THERE WILL BE AT LEAST GALE FORCE GUSTS ACROSS THE NEARSHORE WATERS
AND SOUTH HALF OF THE LAKE THIS AFTERNOON...AND HAVE THAT INCLUDED
IN THE FORECAST. WINDS WILL FURTHER INCREASE TONIGHT WITH HIGH END
GALES TO 45 KT EXPECTED ACROSS THE SOUTH HALF AND NEARSHORE...AND
THEN STORM FORCE WINDS TO 50KT ACROSS THE NORTH HALF. THERE WILL
BE A POSSIBILITY FOR STORM FORCE WINDS ACROSS THE SOUTH HALF AND
NEARSHORE...BUT AT THIS TIME...THIS LOOKS TO BE ONLY FOR A SMALL
WINDOW. HOWEVER...WILL NEED TO MONITOR THE POTENTIAL FOR A LONGER
PERIOD OF POSSIBLE STORM FORCE WINDS IN THOSE LOCATIONS. WINDS
WILL BEGIN TO COME DOWN ON THURSDAY...BUT WITH STORM AND GALES
HOLDING ONTO A LITTLE LONGER ON THE NORTH HALF. HAVE GALES GOING
ACROSS THE NORTH INTO THE AFTERNOON...BUT THERE IS A POSSIBILITY
THAT THEY MAY CONTINUE EVEN INTO IN THE EVENING.
RODRIGUEZ
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WIND ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-ILZ011-
ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-ILZ023-
ILZ032-ILZ033-ILZ039...6 PM WEDNESDAY TO 3 AM THURSDAY.
IN...WIND ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019...6 PM
WEDNESDAY TO 3 AM THURSDAY.
LM...GALE WARNING...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-
LMZ779...6 PM WEDNESDAY TO 9 PM WEDNESDAY.
GALE WARNING...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745...3 AM
THURSDAY TO 6 AM THURSDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 6 PM WEDNESDAY.
STORM WARNING...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-
LMZ779...9 PM WEDNESDAY TO 3 AM THURSDAY.
DENSE FOG ADVISORY...LMZ777-LMZ779 UNTIL 6 PM WEDNESDAY.
GALE WARNING...LMZ777-LMZ779...3 AM THURSDAY TO 9 AM THURSDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
236 PM CST WED DEC 23 2015
.MESOSCALE DISCUSSION...
1230 PM CST
THE FIRST BATCH OF SHOWERS AND THUNDERSTORMS IS EXITING THE AREA
TOWARD THE EAST EARLY THIS AFTERNOON WHILE THE NEXT ROUND IS
APPROACHING OUT OF SOUTHWEST ILLINOIS. BOTH AREAS OF SHOWERS
APPEAR TO BE CORRELATED WITH PRONOUNCED MOISTURE CONVERGENCE AS
DEPICTED IN THE LATEST RUNS OF THE RAP MODEL. THE SECOND AXIS
WOULD BE EXPANDING ACROSS THE AREA IN THE 20-22 UTC TIMEFRAME
ACCORDING TO THE RAP...OR MAYBE A BIT EARLIER ACCORDING TO AN
EXTRAPOLATION OF EXISTING UPSTREAM ACTIVITY. THE GREATEST CONCERNS
WITH THIS SECOND CLUSTER OF ACTIVITY...MUCH OF IT AS STRATIFORM
WITH SOME EMBEDDED CELLS...WOULD APPEAR TO BE STRONG WINDS AND
HEAVY RAIN.
THERE ALSO ARE SIGNALS THAT A THIRD AREA OF SCATTERED CONVECTION
MAY DEVELOP ACROSS NORTHWEST ILLINOIS IN THE 20-00 UTC TIMEFRAME
THIS AFTERNOON CLOSER TO THE LOW AND THE APPROACHING WARM FRONT.
THIS WOULD BE ASSOCIATED WITH THE AREA OF CLEARING SEEN IN VIS
SATELLITE IMAGERY LIFTING OUT OF MISSOURI. THE POTENTIAL FOR THIS
CONVECTION TO REMAIN SURFACE BASED AND DISCRETE...AND ITS
PROXIMITY TO THE SURFACE LOW...WOULD RAISE CONCERNS FOR A
POTENTIALLY WIDER VARIETY OF SEVERE WEATHER.
LENNING
&&
.SHORT TERM...
236 PM CST
THROUGH THURSDAY...
A DEEP UPPER TROUGH IS OVER THE CENTRAL CONUS WITH A STRONG MID
LEVEL SHORTWAVE TRACKING NEWD THROUGH THE UPPER MISSOURI VALLEY. A
SERIES OF WEAKER SHORTWAVES HAVE BEEN TRACKING NEWD THROUGH THE
MIDDLE MISSISSIPPI VALLEY...GENERATING SCT STRONG THUNDERSTORMS AS
FAR NORTH AS NERN IL AND NWRN IN EARLIER TODAY. THE SRN STREAM
SHORTWAVE ENERGY IS BEGINNING TO FOCUS TSRA OVER THE LOWER OHIO
VALLEY AND INTO INDIANA THIS AFTERNOON AND THE MAIN AREA OF CONCERN
WITH RESPECT TO TSRA ACTIVITY FOR THE LOCAL AREA WILL BE UNDER THE
MID LEVEL CIRCULATION CENTER. UNDER THE COLD CORE UPPER LOW AND
WITH UNSEASONABLY WARM...MOIST AIR IN PLACE OVER THE REGION...STRONG
LAPSE RATES AND MODEST LOW LEVEL INSTABILITY WILL KEEP A CHANCE FOR
THUNDERSTORMS INTO THE EVENING HOURS. THE LATEST SATELLITE IMAGERY
SHOWS SOME BREAKS IN THE OVERCAST UNDER THE UPPER LOW WITH SOME
CONVECTIVE CLOUD DEVELOPMENT APPARENT. SOME OF THIS ACTIVITY IS
ALREADY GENERATING LIGHTNING OVER IOWA AND NERN MO. LATEST SPC
MESOSCALE ANALYSIS INDICATES AN AREA OF LOW LEVEL INSTABILITY
CONSISTENT WITH THE CURRENT CONVECTIVE DEVELOPMENT AND THE SHORT
RANGE HIGH RES MODEL GUIDANCE INDICATES THAT THERE IS A CHANCE FOR
THUNDERSTORM ACTIVITY TO MAINTAIN INTO THE EVENING HOURS...MOSTLY
ACROSS NRN IL. ALSO...MORNING SOUNDINGS INDICATE STRONG VERTICAL
SHEAR FROM THE SFC THROUGH MID LEVELS...SO LOW-TOPPED SUPERCELL
DEVELOPMENT REMAIN A POSSIBILITY STRONG...DAMAGING WIND...ISOLATED
LARGE HAIL AND A FEW TORNADOES WILL REMAIN A POSSIBILITY INTO THE
EVENING.
ANOTHER CONCERN FOR THE EVENING AND INTO THE OVERNIGHT HOURS WILL BE
STRONG SYNOPTIC SCALE WINDS. AS THE MAIN SFC LOW QUICKLY LIFTS NEWD
FROM ERN IOWA THIS AFTERNOON TO LAKE SUPERIOR WHILE DEEPENING AT
LEAST 10MB BY ARND 06Z...STRONG PRESSURE RISES IN THE WAKE OF THE
LOW WILL HELP GENERATE STRONG SLWY-WLY WINDS WITH SUSTAINED SPEEDS
ARND 30 MPH AND GUSTS OF 40-50 MPH. THE PERIOD OF THE STRONGEST
WINDS WILL BE FROM ARND 03-09Z WHICH WILL BE THE PERIOD OF THE
STRONGEST PRESSURE RISES.
FOR THURSDAY...CONDITIONS WILL BE MUCH QUIETER AS HIGH PRESSURE
BUILDS ACROSS THE REGION. EVEN WITH A STRONG COLD FRONT EXPECTED TO
MOVE ACROSS THE REGION AS THE SFC LOW LIFTS TO THE
NORTHEAST...TEMPERATURES WILL REMAIN ABOVE SEASONABLE NORMAL LEVELS
WITH HIGHS RANGING FROM AROUND 40F OVER THE ROCKFORD AREA TO THE
UPPER 40S SOUTH OF A VALPARAISO TO PONTIAC LINE.
KREIN
&&
.LONG TERM...
316 AM CST
THURSDAY THROUGH TUESDAY...
THURSDAY THROUGH FRIDAY...
ANTI-CYCLONIC FLOW QUICKLY ARRIVES EARLY THUR IN THE WAKE OF THE
DEPARTING TROUGH. THE 500MB PATTERN DOES BECOME QUASI-ZONAL FOR
THUR/FRI...WHICH WILL HELP TO KEEP TEMPS STILL SEVERAL DEGREES
ABOVE CLIMO IN THE LOW/MID 40S CHRISTMAS DAYAND POSSIBLY UPR 40S
FRI. DESPITE THE SFC RIDGE SLIDING OVERHEAD CHRISTMAS DAY...SKIES
WILL AT BEST BECOME P-CLOUDY IN THE AFTERNOON. THE DRY WEATHER
WILL ONLY BE SHORT-LIVED THROUGH FRI...AS THE ACTIVE PATTERN
BEGINS TO RAMP BACK-UP AS A TROUGH DIGS INTO THE FOUR- CORNERS
REGION OF THE CONUS. A QUASI-STATIONARY BOUNDARY WILL DEVELOP
ALONG THE TENN VALLEY FRI AFTN...AND WILL BECOME THE FOCUS FOR OUR
WEEKEND.
SATURDAY THROUGH TUESDAY... ENSEMBLES CONTINUE TO HOLD THE HIGH
AMPLITUDE RIDGE ALONG THE EASTERN CONUS WITH THE AFOREMENTIONED
TROUGH REMAINING ACROSS THE SOUTHERN ROCKIES/SOUTHWEST CONUS SAT.
OPERATIONAL GUIDANCE HAS BEEN IN GOOD AGREEMENT WITH A VORT MAX
EJECTING FROM THE TROUGH SAT WITH A SHORTWAVE DEVELOPING ALONG THE
SOUTHERN PLAINS. THIS FEATURE IS PROGGED TO ENERGIZE THE QUASI-
STATIONARY BOUNDARY AND LIFT NORTH. SIMULTANEOUSLY A SFC RIDGE IS
PROGGED TO DROP SOUTH FROM CENTRAL CANADA AND COVER MUCH OF THE
UPPER MIDWEST. THE INITIAL WAVE WILL BRING PRECIP BACK TO THE AREA
SAT/SAT NGT...THEN STRONG SFC RIDGE ACROSS THE HIGH PLAINS WILL
STEER THE BOUNDARY BACK SOUTH SUN.
THE MAIN CONCERN WILL BE ON THE DIRECTION AND STRENGTH OF THE
CANADIAN SFC RIDGE OVER THE NORTHERN PLAINS. GUIDANCE INDICATES THIS
FEATURE WILL SLIDE EAST AND COULD DEVELOP A SHARP BAROCLINIC ZONE
ACROSS THE GREAT LAKES REGION. WITH WINDS TURNING NORTHEAST AND A
BOUNDARY LIFTING BACK NORTH SUN NGT/MON...P-TYPE CONCERNS COULD BE
INTRODUCED BEFORE TEMPS WARM ENOUGH.
TEMPS SAT WILL WARM BACK INTO THE UPR 40S TO LOW 50S...THEN WITH THE
BOUNDARY SLIDING SOUTH SUN HIGHS WILL REMAIN IN THE UPR 30S TO LOW
40S. THEN FOR THE REMAINDER OF THE EXTENDED TEMPS COULD TREND BACK
TOWARDS THE MID/UPR 30S.
BEACHLER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* POTENTIAL FOR A FEW ADDITIONAL STRONG STORMS EARLY THIS EVENING
(01-03 UTC).
* INCREASING SOUTHERLY WINDS THIS AFTERNOON.
* POTENTIAL FOR VERY STRONG SOUTHWESTERLY WINDS FOR A SHORT PERIOD
THIS EVENING BETWEEN 03-06 UTC. GUSTS OF 45 TO 50 KT POSSIBLE
DURING THIS PERIOD.
KJB
//DISCUSSION...UPDATED 18Z...
A SIGNIFICANT STORM SYSTEM WILL CONTINUE TO IMPACT THE REGION INTO
TONIGHT. THE MAIN AVIATION WEATHER CONCERNS WILL BE THE POTENTIAL
FOR ADDITIONAL SCT STRONG THUNDERSTORMS EARLY THIS EVENING...GUSTY
SOUTH WINDS THIS AFTERNOON...FOLLOWED BY A PERIOD OF VERY STRONG
GUSTY SYNOPTIC SOUTHWESTERLY WINDS LATER THIS EVENING.
CURRENTLY AN AREA OF MAINLY SHOWERS...WITH A FEW EMBEDDED
THUNDERSTORMS...CONTINUES TO MOVE ACROSS THE EASTERN AIRFIELDS AS A
WARM FRONT GRADUALLY SHIFTS NORTHWARD OVER THE AREA. THIS SHOWERS
ACTIVITY WILL BEGIN TO MOVE OUT OF THE AREA AROUND...OR SLIGHTLY
AFTER THE 19 UTC HOUR...WITH ONLY SOME WIDELY SCT SHOWERS POSSIBLE
THEREAFTER. CIGS AND VSBYS WILL ALSO BE IMPROVING THIS
AFTERNOON...THOUGH THE SURFACE WINDS WILL CONTINUE TO BECOME DUE
SOUTHERLY AND GUSTY...UP AROUND 30 KT THROUGH THE REST OF THE
AFTERNOON.
ANOTHER BATCH OF SCATTERED THUNDERSTORMS MAY DEVELOP VERY LATE THIS
AFTERNOON OVER WESTERN ILLINOIS AHEAD OF AN APPROACHING COLD FRONT.
THESE STORMS COULD THEN PROGRESS EAST-NORTHEASTWARD OVER THE EASTERN
TERMINALS EARLY THIS EVENING...ROUGHLY BETWEEN 00 AND 03 UTC THIS
EVENING. THE POTENTIAL FOR STORMS AT A GIVEN TERMINAL WILL LIKELY BE
FAIRLY SHORT (UNDER AN HOUR)...THOUGH EXACT TIMING REQUIRES A 2 HOUR
TEMPO AT THIS RANGE. THESE POTENTIAL STORMS ALSO HAVE A CONDITIONAL
RISK OF BEING SEVERE WITH STRONG SURFACE WINDS.
FOLLOWING THE COLD FRONTAL PASSAGE...AROUND 02-03 UTC THIS
EVENING...IT APPEARS THAT THE SURFACE WINDS OUTSIDE OF THUNDERSTORMS
COULD BECOME VERY STRONG FOR A SHORT PERIOD. VERY STRONG PRESSURE
RISES LOOK TO OVERSPREAD THE AREA BEHIND THIS FRONT...AND THIS COULD
LEAD TO VERY EFFICIENT TRANSPORT OF STRONGER WINDS ALOFT TO THE
SURFACE MID TO LATE THIS EVENING. WIND GUSTS COULD BRIEFLY GUST IN
THE 45 TO 50 KT RANGE DURING THIS PERIOD...BEFORE ABATING
OVERNIGHT.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* MEDIUM WITH TSRA/TIMING THIS EVENING.
* MEDIUM HIGH WITH WIND FORECAST.
KJB
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT...VFR.
FRIDAY...VFR.
SATURDAY...SHOWERS. CHANCE OF MVFR/IFR.
SUNDAY...CHANCE OF RAIN/SNOW/SLEET AND MVFR CIGS.
MONDAY...CHANCE OF RAIN/SNOW/SLEET AND MVFR CIGS.
TUESDAY...CHANCE OF RAIN/SNOW AND MVFR CIGS.
RODRIGUEZ
&&
.MARINE...
446 AM CST
SIGNIFICANT CHANGES MADE TO WINDS/WAVES FOR THIS FORECAST
PERIOD...WITH STORM FORCE WINDS AND GALES LIKELY ACROSS THE ENTIRE
LAKE LATER TODAY...TONIGHT...AND THURSDAY.
SOUTHEAST WINDS WILL CONTINUE TO INCREASE TODAY AS LOW PRESSURE OVER
THE CENTRAL PLAINS LIFTS NORTHEAST ACROSS THE REGION. EXPECT WINDS
TO REALLY RAMP UP THIS AFTERNOON...WITH TO 30KT WINDS BEING OBSERVED
ACROSS ALL OF THE LAKE. ALTHOUGH NOT OVERLY CONFIDENT...DO THINK
THERE WILL BE AT LEAST GALE FORCE GUSTS ACROSS THE NEARSHORE WATERS
AND SOUTH HALF OF THE LAKE THIS AFTERNOON...AND HAVE THAT INCLUDED
IN THE FORECAST. WINDS WILL FURTHER INCREASE TONIGHT WITH HIGH END
GALES TO 45 KT EXPECTED ACROSS THE SOUTH HALF AND NEARSHORE...AND
THEN STORM FORCE WINDS TO 50KT ACROSS THE NORTH HALF. THERE WILL
BE A POSSIBILITY FOR STORM FORCE WINDS ACROSS THE SOUTH HALF AND
NEARSHORE...BUT AT THIS TIME...THIS LOOKS TO BE ONLY FOR A SMALL
WINDOW. HOWEVER...WILL NEED TO MONITOR THE POTENTIAL FOR A LONGER
PERIOD OF POSSIBLE STORM FORCE WINDS IN THOSE LOCATIONS. WINDS
WILL BEGIN TO COME DOWN ON THURSDAY...BUT WITH STORM AND GALES
HOLDING ONTO A LITTLE LONGER ON THE NORTH HALF. HAVE GALES GOING
ACROSS THE NORTH INTO THE AFTERNOON...BUT THERE IS A POSSIBILITY
THAT THEY MAY CONTINUE EVEN INTO IN THE EVENING.
RODRIGUEZ
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WIND ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-ILZ011-
ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-ILZ023-
ILZ032-ILZ033-ILZ039...6 PM WEDNESDAY TO 3 AM THURSDAY.
IN...WIND ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019...6 PM
WEDNESDAY TO 3 AM THURSDAY.
LM...GALE WARNING...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-
LMZ779...6 PM WEDNESDAY TO 9 PM WEDNESDAY.
GALE WARNING...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745...3 AM
THURSDAY TO 6 AM THURSDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 6 PM WEDNESDAY.
STORM WARNING...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-
LMZ779...9 PM WEDNESDAY TO 3 AM THURSDAY.
DENSE FOG ADVISORY...LMZ777-LMZ779 UNTIL 6 PM WEDNESDAY.
GALE WARNING...LMZ777-LMZ779...3 AM THURSDAY TO 9 AM THURSDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
158 PM CST WED DEC 23 2015
.MESOSCALE DISCUSSION...
1230 PM CST
THE FIRST BATCH OF SHOWERS AND THUNDERSTORMS IS EXITING THE AREA
TOWARD THE EAST EARLY THIS AFTERNOON WHILE THE NEXT ROUND IS
APPROACHING OUT OF SOUTHWEST ILLINOIS. BOTH AREAS OF SHOWERS
APPEAR TO BE CORRELATED WITH PRONOUNCED MOISTURE CONVERGENCE AS
DEPICTED IN THE LATEST RUNS OF THE RAP MODEL. THE SECOND AXIS
WOULD BE EXPANDING ACROSS THE AREA IN THE 20-22 UTC TIMEFRAME
ACCORDING TO THE RAP...OR MAYBE A BIT EARLIER ACCORDING TO AN
EXTRAPOLATION OF EXISTING UPSTREAM ACTIVITY. THE GREATEST CONCERNS
WITH THIS SECOND CLUSTER OF ACTIVITY...MUCH OF IT AS STRATIFORM
WITH SOME EMBEDDED CELLS...WOULD APPEAR TO BE STRONG WINDS AND
HEAVY RAIN.
THERE ALSO ARE SIGNALS THAT A THIRD AREA OF SCATTERED CONVECTION
MAY DEVELOP ACROSS NORTHWEST ILLINOIS IN THE 20-00 UTC TIMEFRAME
THIS AFTERNOON CLOSER TO THE LOW AND THE APPROACHING WARM FRONT.
THIS WOULD BE ASSOCIATED WITH THE AREA OF CLEARING SEEN IN VIS
SATELLITE IMAGERY LIFTING OUT OF MISSOURI. THE POTENTIAL FOR THIS
CONVECTION TO REMAIN SURFACE BASED AND DISCRETE...AND ITS
PROXIMITY TO THE SURFACE LOW...WOULD RAISE CONCERNS FOR A
POTENTIALLY WIDER VARIETY OF SEVERE WEATHER.
LENNING
&&
.SHORT TERM...
316 AM CST
THROUGH TONIGHT...
EARLY THIS MORNING AREAS OF FOG HAVE DEVELOPED WITH A FEW POCKETS
OF DENSE FOG. TEMPS HAVE CONTINUED TO SLOWLY RISE INTO THE MID/UPR
40S...WITH DEW POINTS EQUALLY RISING INTO THE LOW 40S. SFC WINDS
HAVE BACKED TO THE SOUTHEAST WITH SHALLOW STRATUS CLOUDS BLANKETED
ACROSS MUCH OF THE REGION. THE WARM FRONTAL BOUNDARY REMAINS
ORIENTED ACROSS CENTRAL ILLINOIS...AND STEADILY LIFTING NORTH.
ALONG AND SOUTH OF THIS BOUNDARY TEMPS/DEW POINTS HAVE RISEN INTO
THE LOW 50S WITH STRONGER SOUTHERLY WINDS HELPING TO PUMP
ADDITIONAL WARM AIR NORTH.
THE MAIN CONCERN REMAINS ON THE POTENTIAL FOR SEVERE STORMS LATER
TODAY INTO EARLY THIS EVENING. OPERATIONAL GUIDANCE CONTINUES TO
LIFT THE WARM/MOIST BOUNDARY NORTH ACROSS THE FORECAST AREA THIS
MORNING. RAIN IS EXPECTED TO OVERSPREAD THE AREA BY LATE MORNING. IR
IMAGERY EARLY THIS MORNING SHOWS A DRY WEDGE ACROSS CENTRAL
OKLAHOMA...AND HI-RES OPERATIONAL GUIDANCE HAS INITIALIZED THIS
FEATURE WELL. BY MIDDAY THIS FEATURE WILL BE LIFTING INTO CENTRAL
MISSOURI...WHICH COULD BRING A BRIEF LULL IN RAIN ACROSS THE
FORECAST AREA BY MID AFTN. BY EARLY AFTN THE 500MB TROUGH WILL
BECOME NEGATIVELY TILTED WITH THE SPEED MAX POSITIONED OVER EASTERN
KANSAS AND LIFTING NORTHEAST TOWARDS EASTERN IOWA. THE DRY WEDGE MAY
HELP FURTHER DESTABILIZE THE AIRMASS ACROSS THE CWFA...HOWEVER THIS
REMAINS THE LARGEST CHALLENGE FOR SEVERE STORMS. LOW LEVEL SHEAR
REMAINS VERY STRONG JUST EAST OF THE SFC LOW TRACK...WHICH IS
PRESENTLY POISED TO CLIP FAR NORTHWEST IL LATE THIS AFTN. THIS COULD
SUPPORT AN ISOLATED TORNADO THREAT IN THIS MOST SHEARED AREA.
NONETHELESS...THE 40-55KT LOW LEVEL JET WILL EQUALLY SUPPORT FAST
MOVING STORMS IF THEY ARE CAPABLE OF DEVELOPING...WHICH MAINTAINS
THE DAMAGING WIND THREAT. HIGHS TODAY COULD BREAK RECORDS IN MANY
AREAS OF NORTHERN IL. CURRENT EXPECTATION IS THAT TEMPS WILL RISE TO
AROUND 60 AND PERHAPS THE MIDDLE 60S ACROSS PORTIONS OF THE SOUTHERN
CWFA.
THE SEVERE THREAT WILL CONTINUE TO JUST BEYOND 00Z...BUT SHOULD BE
QUICKLY PIVOTING EAST BY 2-3Z OF THE CWFA. SO HAVE ONLY HELD ONTO
THE SEVERE WORDING IN THE FORECAST UNTIL THIS TIMEFRAME...WITH MOST
OPERATIONAL GUIDANCE RAPIDLY ERODING THE MOISTURE TO THE NORTHEAST
IN THE WAKE OF THE STRONG SFC LOW. IN ADDITION TO THE AFTN/EARLY EVE
SEVERE THREAT...AND AS ELUDED TO WITH THE STRONG LOW LEVEL
WINDS...THE ISALLOBARIC PRESSURE RISES ON THE BACKSIDE OF THE
SHORTWAVE WILL BE SUPPORTIVE OF AT LEAST GUSTS TO 45 MPH OR WIND
ADVISORY CRITERIA...BUT A FEW GUSTS COULD APPROACH WIND WARNING
CRITERIA.
BEACHLER
&&
.LONG TERM...
316 AM CST
THURSDAY THROUGH TUESDAY...
THURSDAY THROUGH FRIDAY...
ANTI-CYCLONIC FLOW QUICKLY ARRIVES EARLY THUR IN THE WAKE OF THE
DEPARTING TROUGH. THE 500MB PATTERN DOES BECOME QUASI-ZONAL FOR
THUR/FRI...WHICH WILL HELP TO KEEP TEMPS STILL SEVERAL DEGREES
ABOVE CLIMO IN THE LOW/MID 40S CHRISTMAS DAYAND POSSIBLY UPR 40S
FRI. DESPITE THE SFC RIDGE SLIDING OVERHEAD CHRISTMAS DAY...SKIES
WILL AT BEST BECOME P-CLOUDY IN THE AFTERNOON. THE DRY WEATHER
WILL ONLY BE SHORT-LIVED THROUGH FRI...AS THE ACTIVE PATTERN
BEGINS TO RAMP BACK-UP AS A TROUGH DIGS INTO THE FOUR- CORNERS
REGION OF THE CONUS. A QUASI-STATIONARY BOUNDARY WILL DEVELOP
ALONG THE TENN VALLEY FRI AFTN...AND WILL BECOME THE FOCUS FOR OUR
WEEKEND.
SATURDAY THROUGH TUESDAY... ENSEMBLES CONTINUE TO HOLD THE HIGH
AMPLITUDE RIDGE ALONG THE EASTERN CONUS WITH THE AFOREMENTIONED
TROUGH REMAINING ACROSS THE SOUTHERN ROCKIES/SOUTHWEST CONUS SAT.
OPERATIONAL GUIDANCE HAS BEEN IN GOOD AGREEMENT WITH A VORT MAX
EJECTING FROM THE TROUGH SAT WITH A SHORTWAVE DEVELOPING ALONG THE
SOUTHERN PLAINS. THIS FEATURE IS PROGGED TO ENERGIZE THE QUASI-
STATIONARY BOUNDARY AND LIFT NORTH. SIMULTANEOUSLY A SFC RIDGE IS
PROGGED TO DROP SOUTH FROM CENTRAL CANADA AND COVER MUCH OF THE
UPPER MIDWEST. THE INITIAL WAVE WILL BRING PRECIP BACK TO THE AREA
SAT/SAT NGT...THEN STRONG SFC RIDGE ACROSS THE HIGH PLAINS WILL
STEER THE BOUNDARY BACK SOUTH SUN.
THE MAIN CONCERN WILL BE ON THE DIRECTION AND STRENGTH OF THE
CANADIAN SFC RIDGE OVER THE NORTHERN PLAINS. GUIDANCE INDICATES THIS
FEATURE WILL SLIDE EAST AND COULD DEVELOP A SHARP BAROCLINIC ZONE
ACROSS THE GREAT LAKES REGION. WITH WINDS TURNING NORTHEAST AND A
BOUNDARY LIFTING BACK NORTH SUN NGT/MON...P-TYPE CONCERNS COULD BE
INTRODUCED BEFORE TEMPS WARM ENOUGH.
TEMPS SAT WILL WARM BACK INTO THE UPR 40S TO LOW 50S...THEN WITH THE
BOUNDARY SLIDING SOUTH SUN HIGHS WILL REMAIN IN THE UPR 30S TO LOW
40S. THEN FOR THE REMAINDER OF THE EXTENDED TEMPS COULD TREND BACK
TOWARDS THE MID/UPR 30S.
BEACHLER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* POTENTIAL FOR A FEW ADDITIONAL STRONG STORMS EARLY THIS EVENING
(01-03 UTC).
* INCREASING SOUTHERLY WINDS THIS AFTERNOON.
* POTENTIAL FOR VERY STRONG SOUTHWESTERLY WINDS FOR A SHORT PERIOD
THIS EVENING BETWEEN 03-06 UTC. GUSTS OF 45 TO 50 KT POSSIBLE
DURING THIS PERIOD.
KJB
//DISCUSSION...UPDATED 18Z...
A SIGNIFICANT STORM SYSTEM WILL CONTINUE TO IMPACT THE REGION INTO
TONIGHT. THE MAIN AVIATION WEATHER CONCERNS WILL BE THE POTENTIAL
FOR ADDITIONAL SCT STRONG THUNDERSTORMS EARLY THIS EVENING...GUSTY
SOUTH WINDS THIS AFTERNOON...FOLLOWED BY A PERIOD OF VERY STRONG
GUSTY SYNOPTIC SOUTHWESTERLY WINDS LATER THIS EVENING.
CURRENTLY AN AREA OF MAINLY SHOWERS...WITH A FEW EMBEDDED
THUNDERSTORMS...CONTINUES TO MOVE ACROSS THE EASTERN AIRFIELDS AS A
WARM FRONT GRADUALLY SHIFTS NORTHWARD OVER THE AREA. THIS SHOWERS
ACTIVITY WILL BEGIN TO MOVE OUT OF THE AREA AROUND...OR SLIGHTLY
AFTER THE 19 UTC HOUR...WITH ONLY SOME WIDELY SCT SHOWERS POSSIBLE
THEREAFTER. CIGS AND VSBYS WILL ALSO BE IMPROVING THIS
AFTERNOON...THOUGH THE SURFACE WINDS WILL CONTINUE TO BECOME DUE
SOUTHERLY AND GUSTY...UP AROUND 30 KT THROUGH THE REST OF THE
AFTERNOON.
ANOTHER BATCH OF SCATTERED THUNDERSTORMS MAY DEVELOP VERY LATE THIS
AFTERNOON OVER WESTERN ILLINOIS AHEAD OF AN APPROACHING COLD FRONT.
THESE STORMS COULD THEN PROGRESS EAST-NORTHEASTWARD OVER THE EASTERN
TERMINALS EARLY THIS EVENING...ROUGHLY BETWEEN 00 AND 03 UTC THIS
EVENING. THE POTENTIAL FOR STORMS AT A GIVEN TERMINAL WILL LIKELY BE
FAIRLY SHORT (UNDER AN HOUR)...THOUGH EXACT TIMING REQUIRES A 2 HOUR
TEMPO AT THIS RANGE. THESE POTENTIAL STORMS ALSO HAVE A CONDITIONAL
RISK OF BEING SEVERE WITH STRONG SURFACE WINDS.
FOLLOWING THE COLD FRONTAL PASSAGE...AROUND 02-03 UTC THIS
EVENING...IT APPEARS THAT THE SURFACE WINDS OUTSIDE OF THUNDERSTORMS
COULD BECOME VERY STRONG FOR A SHORT PERIOD. VERY STRONG PRESSURE
RISES LOOK TO OVERSPREAD THE AREA BEHIND THIS FRONT...AND THIS COULD
LEAD TO VERY EFFICIENT TRANSPORT OF STRONGER WINDS ALOFT TO THE
SURFACE MID TO LATE THIS EVENING. WIND GUSTS COULD BRIEFLY GUST IN
THE 45 TO 50 KT RANGE DURING THIS PERIOD...BEFORE ABATING
OVERNIGHT.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* MEDIUM WITH TSRA/TIMING THIS EVENING.
* MEDIUM HIGH WITH WIND FORECAST.
KJB
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT...VFR.
FRIDAY...VFR.
SATURDAY...SHOWERS. CHANCE OF MVFR/IFR.
SUNDAY...CHANCE OF RAIN/SNOW/SLEET AND MVFR CIGS.
MONDAY...CHANCE OF RAIN/SNOW/SLEET AND MVFR CIGS.
TUESDAY...CHANCE OF RAIN/SNOW AND MVFR CIGS.
RODRIGUEZ
&&
.MARINE...
446 AM CST
SIGNIFICANT CHANGES MADE TO WINDS/WAVES FOR THIS FORECAST
PERIOD...WITH STORM FORCE WINDS AND GALES LIKELY ACROSS THE ENTIRE
LAKE LATER TODAY...TONIGHT...AND THURSDAY.
SOUTHEAST WINDS WILL CONTINUE TO INCREASE TODAY AS LOW PRESSURE OVER
THE CENTRAL PLAINS LIFTS NORTHEAST ACROSS THE REGION. EXPECT WINDS
TO REALLY RAMP UP THIS AFTERNOON...WITH TO 30KT WINDS BEING OBSERVED
ACROSS ALL OF THE LAKE. ALTHOUGH NOT OVERLY CONFIDENT...DO THINK
THERE WILL BE AT LEAST GALE FORCE GUSTS ACROSS THE NEARSHORE WATERS
AND SOUTH HALF OF THE LAKE THIS AFTERNOON...AND HAVE THAT INCLUDED
IN THE FORECAST. WINDS WILL FURTHER INCREASE TONIGHT WITH HIGH END
GALES TO 45 KT EXPECTED ACROSS THE SOUTH HALF AND NEARSHORE...AND
THEN STORM FORCE WINDS TO 50KT ACROSS THE NORTH HALF. THERE WILL
BE A POSSIBILITY FOR STORM FORCE WINDS ACROSS THE SOUTH HALF AND
NEARSHORE...BUT AT THIS TIME...THIS LOOKS TO BE ONLY FOR A SMALL
WINDOW. HOWEVER...WILL NEED TO MONITOR THE POTENTIAL FOR A LONGER
PERIOD OF POSSIBLE STORM FORCE WINDS IN THOSE LOCATIONS. WINDS
WILL BEGIN TO COME DOWN ON THURSDAY...BUT WITH STORM AND GALES
HOLDING ONTO A LITTLE LONGER ON THE NORTH HALF. HAVE GALES GOING
ACROSS THE NORTH INTO THE AFTERNOON...BUT THERE IS A POSSIBILITY
THAT THEY MAY CONTINUE EVEN INTO IN THE EVENING.
RODRIGUEZ
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WIND ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-ILZ011-
ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-ILZ023-
ILZ032-ILZ033-ILZ039...6 PM WEDNESDAY TO 3 AM THURSDAY.
IN...WIND ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019...6 PM
WEDNESDAY TO 3 AM THURSDAY.
LM...GALE WARNING...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-
LMZ779...6 PM WEDNESDAY TO 9 PM WEDNESDAY.
GALE WARNING...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745...3 AM
THURSDAY TO 6 AM THURSDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 6 PM WEDNESDAY.
STORM WARNING...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-
LMZ779...9 PM WEDNESDAY TO 3 AM THURSDAY.
DENSE FOG ADVISORY...LMZ777-LMZ779 UNTIL 6 PM WEDNESDAY.
GALE WARNING...LMZ777-LMZ779...3 AM THURSDAY TO 9 AM THURSDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1236 PM CST WED DEC 23 2015
.MESOSCALE DISCUSSION...
1230 PM CST
THE FIRST BATCH OF SHOWERS AND THUNDERSTORMS IS EXITING THE AREA
TOWARD THE EAST EARLY THIS AFTERNOON WHILE THE NEXT ROUND IS
APPROACHING OUT OF SOUTHWEST ILLINOIS. BOTH AREAS OF SHOWERS
APPEAR TO BE CORRELATED WITH PRONOUNCED MOISTURE CONVERGENCE AS
DEPICTED IN THE LATEST RUNS OF THE RAP MODEL. THE SECOND AXIS
WOULD BE EXPANDING ACROSS THE AREA IN THE 20-22 UTC TIMEFRAME
ACCORDING TO THE RAP...OR MAYBE A BIT EARLIER ACCORDING TO AN
EXTRAPOLATION OF EXISTING UPSTREAM ACTIVITY. THE GREATEST CONCERNS
WITH THIS SECOND CLUSTER OF ACTIVITY...MUCH OF IT AS STRATIFORM
WITH SOME EMBEDDED CELLS...WOULD APPEAR TO BE STRONG WINDS AND
HEAVY RAIN.
THERE ALSO ARE SIGNALS THAT A THIRD AREA OF SCATTERED CONVECTION
MAY DEVELOP ACROSS NORTHWEST ILLINOIS IN THE 20-00 UTC TIMEFRAME
THIS AFTERNOON CLOSER TO THE LOW AND THE APPROACHING WARM FRONT.
THIS WOULD BE ASSOCIATED WITH THE AREA OF CLEARING SEEN IN VIS
SATELLITE IMAGERY LIFTING OUT OF MISSOURI. THE POTENTIAL FOR THIS
CONVECTION TO REMAIN SURFACE BASED AND DISCRETE...AND ITS
PROXIMITY TO THE SURFACE LOW...WOULD RAISE CONCERNS FOR A
POTENTIALLY WIDER VARIETY OF SEVERE WEATHER.
LENNING
&&
.SHORT TERM...
316 AM CST
THROUGH TONIGHT...
EARLY THIS MORNING AREAS OF FOG HAVE DEVELOPED WITH A FEW POCKETS
OF DENSE FOG. TEMPS HAVE CONTINUED TO SLOWLY RISE INTO THE MID/UPR
40S...WITH DEW POINTS EQUALLY RISING INTO THE LOW 40S. SFC WINDS
HAVE BACKED TO THE SOUTHEAST WITH SHALLOW STRATUS CLOUDS BLANKETED
ACROSS MUCH OF THE REGION. THE WARM FRONTAL BOUNDARY REMAINS
ORIENTED ACROSS CENTRAL ILLINOIS...AND STEADILY LIFTING NORTH.
ALONG AND SOUTH OF THIS BOUNDARY TEMPS/DEW POINTS HAVE RISEN INTO
THE LOW 50S WITH STRONGER SOUTHERLY WINDS HELPING TO PUMP
ADDITIONAL WARM AIR NORTH.
THE MAIN CONCERN REMAINS ON THE POTENTIAL FOR SEVERE STORMS LATER
TODAY INTO EARLY THIS EVENING. OPERATIONAL GUIDANCE CONTINUES TO
LIFT THE WARM/MOIST BOUNDARY NORTH ACROSS THE FORECAST AREA THIS
MORNING. RAIN IS EXPECTED TO OVERSPREAD THE AREA BY LATE MORNING. IR
IMAGERY EARLY THIS MORNING SHOWS A DRY WEDGE ACROSS CENTRAL
OKLAHOMA...AND HI-RES OPERATIONAL GUIDANCE HAS INITIALIZED THIS
FEATURE WELL. BY MIDDAY THIS FEATURE WILL BE LIFTING INTO CENTRAL
MISSOURI...WHICH COULD BRING A BRIEF LULL IN RAIN ACROSS THE
FORECAST AREA BY MID AFTN. BY EARLY AFTN THE 500MB TROUGH WILL
BECOME NEGATIVELY TILTED WITH THE SPEED MAX POSITIONED OVER EASTERN
KANSAS AND LIFTING NORTHEAST TOWARDS EASTERN IOWA. THE DRY WEDGE MAY
HELP FURTHER DESTABILIZE THE AIRMASS ACROSS THE CWFA...HOWEVER THIS
REMAINS THE LARGEST CHALLENGE FOR SEVERE STORMS. LOW LEVEL SHEAR
REMAINS VERY STRONG JUST EAST OF THE SFC LOW TRACK...WHICH IS
PRESENTLY POISED TO CLIP FAR NORTHWEST IL LATE THIS AFTN. THIS COULD
SUPPORT AN ISOLATED TORNADO THREAT IN THIS MOST SHEARED AREA.
NONETHELESS...THE 40-55KT LOW LEVEL JET WILL EQUALLY SUPPORT FAST
MOVING STORMS IF THEY ARE CAPABLE OF DEVELOPING...WHICH MAINTAINS
THE DAMAGING WIND THREAT. HIGHS TODAY COULD BREAK RECORDS IN MANY
AREAS OF NORTHERN IL. CURRENT EXPECTATION IS THAT TEMPS WILL RISE TO
AROUND 60 AND PERHAPS THE MIDDLE 60S ACROSS PORTIONS OF THE SOUTHERN
CWFA.
THE SEVERE THREAT WILL CONTINUE TO JUST BEYOND 00Z...BUT SHOULD BE
QUICKLY PIVOTING EAST BY 2-3Z OF THE CWFA. SO HAVE ONLY HELD ONTO
THE SEVERE WORDING IN THE FORECAST UNTIL THIS TIMEFRAME...WITH MOST
OPERATIONAL GUIDANCE RAPIDLY ERODING THE MOISTURE TO THE NORTHEAST
IN THE WAKE OF THE STRONG SFC LOW. IN ADDITION TO THE AFTN/EARLY EVE
SEVERE THREAT...AND AS ELUDED TO WITH THE STRONG LOW LEVEL
WINDS...THE ISALLOBARIC PRESSURE RISES ON THE BACKSIDE OF THE
SHORTWAVE WILL BE SUPPORTIVE OF AT LEAST GUSTS TO 45 MPH OR WIND
ADVISORY CRITERIA...BUT A FEW GUSTS COULD APPROACH WIND WARNING
CRITERIA.
BEACHLER
&&
.LONG TERM...
316 AM CST
THURSDAY THROUGH TUESDAY...
THURSDAY THROUGH FRIDAY...
ANTI-CYCLONIC FLOW QUICKLY ARRIVES EARLY THUR IN THE WAKE OF THE
DEPARTING TROUGH. THE 500MB PATTERN DOES BECOME QUASI-ZONAL FOR
THUR/FRI...WHICH WILL HELP TO KEEP TEMPS STILL SEVERAL DEGREES
ABOVE CLIMO IN THE LOW/MID 40S CHRISTMAS DAYAND POSSIBLY UPR 40S
FRI. DESPITE THE SFC RIDGE SLIDING OVERHEAD CHRISTMAS DAY...SKIES
WILL AT BEST BECOME P-CLOUDY IN THE AFTERNOON. THE DRY WEATHER
WILL ONLY BE SHORT-LIVED THROUGH FRI...AS THE ACTIVE PATTERN
BEGINS TO RAMP BACK-UP AS A TROUGH DIGS INTO THE FOUR- CORNERS
REGION OF THE CONUS. A QUASI-STATIONARY BOUNDARY WILL DEVELOP
ALONG THE TENN VALLEY FRI AFTN...AND WILL BECOME THE FOCUS FOR OUR
WEEKEND.
SATURDAY THROUGH TUESDAY... ENSEMBLES CONTINUE TO HOLD THE HIGH
AMPLITUDE RIDGE ALONG THE EASTERN CONUS WITH THE AFOREMENTIONED
TROUGH REMAINING ACROSS THE SOUTHERN ROCKIES/SOUTHWEST CONUS SAT.
OPERATIONAL GUIDANCE HAS BEEN IN GOOD AGREEMENT WITH A VORT MAX
EJECTING FROM THE TROUGH SAT WITH A SHORTWAVE DEVELOPING ALONG THE
SOUTHERN PLAINS. THIS FEATURE IS PROGGED TO ENERGIZE THE QUASI-
STATIONARY BOUNDARY AND LIFT NORTH. SIMULTANEOUSLY A SFC RIDGE IS
PROGGED TO DROP SOUTH FROM CENTRAL CANADA AND COVER MUCH OF THE
UPPER MIDWEST. THE INITIAL WAVE WILL BRING PRECIP BACK TO THE AREA
SAT/SAT NGT...THEN STRONG SFC RIDGE ACROSS THE HIGH PLAINS WILL
STEER THE BOUNDARY BACK SOUTH SUN.
THE MAIN CONCERN WILL BE ON THE DIRECTION AND STRENGTH OF THE
CANADIAN SFC RIDGE OVER THE NORTHERN PLAINS. GUIDANCE INDICATES THIS
FEATURE WILL SLIDE EAST AND COULD DEVELOP A SHARP BAROCLINIC ZONE
ACROSS THE GREAT LAKES REGION. WITH WINDS TURNING NORTHEAST AND A
BOUNDARY LIFTING BACK NORTH SUN NGT/MON...P-TYPE CONCERNS COULD BE
INTRODUCED BEFORE TEMPS WARM ENOUGH.
TEMPS SAT WILL WARM BACK INTO THE UPR 40S TO LOW 50S...THEN WITH THE
BOUNDARY SLIDING SOUTH SUN HIGHS WILL REMAIN IN THE UPR 30S TO LOW
40S. THEN FOR THE REMAINDER OF THE EXTENDED TEMPS COULD TREND BACK
TOWARDS THE MID/UPR 30S.
BEACHLER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* SHOWERS WITH EMBEDDED THUNDERSTORMS ENDING EARLY THIS AFTERNOON.
* POTENTIAL FOR A FEW ADDITIONAL STRONG STORMS EARLY THIS
EVENING.
* INCREASING SOUTHERLY WINDS THIS AFTERNOON.
* POTENTIAL FOR VERY STRONG SOUTHWESTERLY WINDS FOR A SHORT PERIOD
THIS EVENING BETWEEN 03-06 UTC. GUSTS OF 45 TO 50 KT POSSIBLE
DURING THIS PERIOD.
KJB
//DISCUSSION...UPDATED 18Z...
A SIGNIFICANT STORM SYSTEM WILL CONTINUE TO IMPACT THE REGION INTO
TONIGHT. THE MAIN AVIATION WEATHER CONCERNS WILL BE THE POTENTIAL
FOR ADDITIONAL SCT STRONG THUNDERSTORMS EARLY THIS EVENING...GUSTY
SOUTH WINDS THIS AFTERNOON...FOLLOWED BY A PERIOD OF VERY STRONG
GUSTY SYNOPTIC SOUTHWESTERLY WINDS LATER THIS EVENING.
CURRENTLY AN AREA OF MAINLY SHOWERS...WITH A FEW EMBEDDED
THUNDERSTORMS...CONTINUES TO MOVE ACROSS THE EASTERN AIRFIELDS AS A
WARM FRONT GRADUALLY SHIFTS NORTHWARD OVER THE AREA. THIS SHOWERS
ACTIVITY WILL BEGIN TO MOVE OUT OF THE AREA AROUND...OR SLIGHTLY
AFTER THE 19 UTC HOUR...WITH ONLY SOME WIDELY SCT SHOWERS POSSIBLE
THEREAFTER. CIGS AND VSBYS WILL ALSO BE IMPROVING THIS
AFTERNOON...THOUGH THE SURFACE WINDS WILL CONTINUE TO BECOME DUE
SOUTHERLY AND GUSTY...UP AROUND 30 KT THROUGH THE REST OF THE
AFTERNOON.
ANOTHER BATCH OF SCATTERED THUNDERSTORMS MAY DEVELOP VERY LATE THIS
AFTERNOON OVER WESTERN ILLINOIS AHEAD OF AN APPROACHING COLD FRONT.
THESE STORMS COULD THEN PROGRESS EAST-NORTHEASTWARD OVER THE EASTERN
TERMINALS EARLY THIS EVENING...ROUGHLY BETWEEN 00 AND 03 UTC THIS
EVENING. THE POTENTIAL FOR STORMS AT A GIVEN TERMINAL WILL LIKELY BE
FAIRLY SHORT (UNDER AN HOUR)...THOUGH EXACT TIMING REQUIRES A 2 HOUR
TEMPO AT THIS RANGE. THESE POTENTIAL STORMS ALSO HAVE A CONDITIONAL
RISK OF BEING SEVERE WITH STRONG SURFACE WINDS.
FOLLOWING THE COLD FRONTAL PASSAGE...AROUND 02-03 UTC THIS
EVENING...IT APPEARS THAT THE SURFACE WINDS OUTSIDE OF THUNDERSTORMS
COULD BECOME VERY STRONG FOR A SHORT PERIOD. VERY STRONG PRESSURE
RISES LOOK TO OVERSPREAD THE AREA BEHIND THIS FRONT...AND THIS COULD
LEAD TO VERY EFFICIENT TRANSPORT OF STRONGER WINDS ALOFT TO THE
SURFACE MID TO LATE THIS EVENING. WIND GUSTS COULD BRIEFLY GUST IN
THE 45 TO 50 KT RANGE DURING THIS PERIOD...BEFORE ABATING
OVERNIGHT.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* MEDIUM WITH TSRA/TIMING THIS EVENING.
* MEDIUM HIGH WITH WIND FORECAST.
KJB
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT...VFR.
FRIDAY...VFR.
SATURDAY...SHOWERS. CHANCE OF MVFR/IFR.
SUNDAY...CHANCE OF RAIN/SNOW/SLEET AND MVFR CIGS.
MONDAY...CHANCE OF RAIN/SNOW/SLEET AND MVFR CIGS.
TUESDAY...CHANCE OF RAIN/SNOW AND MVFR CIGS.
RODRIGUEZ
&&
.MARINE...
446 AM CST
SIGNIFICANT CHANGES MADE TO WINDS/WAVES FOR THIS FORECAST
PERIOD...WITH STORM FORCE WINDS AND GALES LIKELY ACROSS THE ENTIRE
LAKE LATER TODAY...TONIGHT...AND THURSDAY.
SOUTHEAST WINDS WILL CONTINUE TO INCREASE TODAY AS LOW PRESSURE OVER
THE CENTRAL PLAINS LIFTS NORTHEAST ACROSS THE REGION. EXPECT WINDS
TO REALLY RAMP UP THIS AFTERNOON...WITH TO 30KT WINDS BEING OBSERVED
ACROSS ALL OF THE LAKE. ALTHOUGH NOT OVERLY CONFIDENT...DO THINK
THERE WILL BE AT LEAST GALE FORCE GUSTS ACROSS THE NEARSHORE WATERS
AND SOUTH HALF OF THE LAKE THIS AFTERNOON...AND HAVE THAT INCLUDED
IN THE FORECAST. WINDS WILL FURTHER INCREASE TONIGHT WITH HIGH END
GALES TO 45 KT EXPECTED ACROSS THE SOUTH HALF AND NEARSHORE...AND
THEN STORM FORCE WINDS TO 50KT ACROSS THE NORTH HALF. THERE WILL
BE A POSSIBILITY FOR STORM FORCE WINDS ACROSS THE SOUTH HALF AND
NEARSHORE...BUT AT THIS TIME...THIS LOOKS TO BE ONLY FOR A SMALL
WINDOW. HOWEVER...WILL NEED TO MONITOR THE POTENTIAL FOR A LONGER
PERIOD OF POSSIBLE STORM FORCE WINDS IN THOSE LOCATIONS. WINDS
WILL BEGIN TO COME DOWN ON THURSDAY...BUT WITH STORM AND GALES
HOLDING ONTO A LITTLE LONGER ON THE NORTH HALF. HAVE GALES GOING
ACROSS THE NORTH INTO THE AFTERNOON...BUT THERE IS A POSSIBILITY
THAT THEY MAY CONTINUE EVEN INTO IN THE EVENING.
RODRIGUEZ
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WIND ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-ILZ011-
ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-ILZ023-
ILZ032-ILZ033-ILZ039...6 PM WEDNESDAY TO 3 AM THURSDAY.
IN...WIND ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019...6 PM
WEDNESDAY TO 3 AM THURSDAY.
LM...GALE WARNING...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-
LMZ779...6 PM WEDNESDAY TO 9 PM WEDNESDAY.
GALE WARNING...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745...3 AM
THURSDAY TO 6 AM THURSDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 6 PM WEDNESDAY.
STORM WARNING...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-
LMZ779...9 PM WEDNESDAY TO 3 AM THURSDAY.
DENSE FOG ADVISORY...LMZ777-LMZ779 UNTIL 6 PM WEDNESDAY.
GALE WARNING...LMZ777-LMZ779...3 AM THURSDAY TO 9 AM THURSDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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AREA FORECAST DISCUSSION
National Weather Service Lincoln IL
1158 AM CST WED DEC 23 2015
.SHORT TERM...(Today)
ISSUED AT 330 AM CST WED DEC 23 2015
09z/3am surface analysis shows a 986mb low over south-central Kansas
with a warm front extending eastward across Missouri into southern
Illinois. Southerly flow to the south of the front has resulted in
temperatures steadily rising into the lower 60s across Kentucky and
far southern Illinois...and well into the 50s further north across
the KILX CWA. Due to low-level warm/moist advection, widespread fog
has developed along/east of a Bloomington to Taylorville line. Do
not think dense fog will be an issue however, as surface winds have
been strong enough to provide enough mixing of the atmosphere to
keep vsbys around 1 mile at the lowest. HRRR shows the fog
persisting through early morning before gradually dissipating and
pushing further north.
Current water vapor imagery shows vigorous short-wave trough
tracking across the Oklahoma/Texas panhandles, and this feature is
already triggering widespread convection across eastern Oklahoma
into Arkansas. 4km WRF-NMM has a very good handle on the convection
and shows it tracking northeastward into central Illinois after
13/14z. Based on this forecast and current radar trends, have gone
with categorical PoPs for showers/thunder this morning. This
initial surge of convection will lift into northern Illinois toward
midday, resulting in a lull in the precip across the KILX CWA by
early afternoon. May even see a few breaks in the overcast as per
the HRRR cloud height forecast. Big question then becomes how much
convection will develop along an advancing cold front late this
afternoon into the evening. Several models suggest much of central
Illinois may only see scattered thunderstorms, with the more
concentrated area of convection further south from the I-70 corridor
southward into the Tennessee River Valley. Given robust instability
characterized by SBCAPEs of 500-1000J/kg and strong 0-6km bulk shear
of 70-80kt, have continued with categorical PoPs along/ahead of the
front this afternoon. Have also mentioned severe, as latest Day 1
outlook from SPC now places the entire area under a Slight Risk.
Aside from the storm chances, this will be a windy and extremely
warm day. Southerly winds will gust to between 35 and 40 mph,
helping push temperatures to near record levels in the middle to
upper 60s. In fact, if a few breaks do indeed develop in the
overcast, would not be surprised to see temps rise into the lower
70s in a few spots.
.LONG TERM...(Tonight through Tuesday)
ISSUED AT 330 AM CST WED DEC 23 2015
As deep low pressure tracks from eastern Iowa this evening to Lake
Superior by midnight, impressive pressure rises will create very
strong southwesterly winds across the area this evening behind the
departing cold front. A Wind Advisory may need to be issued for
areas north of the I-70 corridor, as gusts could exceed 40 mph. Will
hold off on the advisory for now, waiting until the strong to
potentially severe convection clears the area later today.
Showers/storms will quickly exit into Indiana by midnight, with dry
weather expected overnight.
A lull in the action is still anticipated for Thursday into Friday,
with slightly cooler high temperatures in the 40s and 50s. After
that, a wet/unsettled weekend is on tap. 00z Dec 23 models are in
relatively good agreement concerning the heavy rain set-up
initially, with both the GFS and ECMWF showing widespread showers
and even a few thunderstorms for Saturday/Saturday night. Latest
GFS is beginning to look more like previous runs of the ECMWF, which
shows a northern stream short-wave pushing the main baroclinic zone
southward into the Ohio River Valley on Sunday. In fact, the latest
ECMWF now shows the front south of the Ohio River and features dry
weather across central Illinois Sunday afternoon and night. Am not
ready to go quite that far yet, although the southward trend is
definitely there. Have therefore lowered PoPs substantially across
the northern half of the CWA Sunday/Sunday night and have pushed
thunder mention further south out of the area. Closed upper low
over the Desert Southwest will eventually eject northeastward,
bringing higher PoPs back by Monday/Monday night. Rain chances will
then finally decrease by Tuesday as the low lifts into the Great
Lakes.
&&
.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
ISSUED AT 1149 AM CST WED DEC 23 2015
Active convective weather with a complex weather system can be
expected in central and eastern IL this afternoon through this
evening. The majority of the area is in the warm sector of the
storm system, so ceilings have come up considerably due to this
and the high winds from the mixing of the lower atmosphere.
Several rounds of showers/t-storms will impact central and eastern
IL TAF sites through at least 20-21 UTC before the next round
approaches/develops in the 21-03 UTC timeframe. Added a TEMPO
group to not only highlight the MVFR visibility/ceilings from the
moderate to heavy rain, but also wind gusts exceeding 40 kts from
the strongest thunderstorms.
Outside of the thunderstorms, VFR conditions are anticipated.
However, an increasing pressure gradient this afternoon through
the evening will result in south to southwest winds of 25-30 kts
with gusts around 35 kts.
The sky is expected to partially clear and wind settle down a bit
after midnight local time. Increasing mid level clouds are
anticipated by mid-morning Thursday, but conditions will be VFR.
&&
.CLIMATE...
ISSUED AT 458 AM CST WED DEC 23 2015
Record highs for today:
Bloomington/Normal......... 63 in 1933
Champaign/Urbana........... 64 in 1933
Charleston/Mattoon......... 69 in 1933
Danville................... 65 in 1933
Decatur.................... 66 in 1933
Effingham.................. 68 in 1933
Jacksonville............... 70 in 1933
Lincoln.................... 65 in 1933
Olney...................... 67 in 1931
Peoria..................... 65 in 1933
Springfield................ 66 in 1933
&&
.ILX Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...Barnes
LONG TERM...Barnes
AVIATION...Miller
CLIMATE...Barnes
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1147 AM CST WED DEC 23 2015
.SHORT TERM /TODAY/...
ISSUED AT 410 AM CST WED DEC 23 2015
MORNING WATER VAPOR IMAGERY DEPICTS A SEASONABLY STRONG NEGATIVELY
TILTED LONGWAVE TROUGH AXIS SITUATED DOWN THE EASTERN FLANK OF THE
ROCKIES WITH A 150 KT JET IMPINGING ALONG ITS SOUTHWEST FLANK. AN
EMBEDDED SHORTWAVE/PV ANOMALY WILL EJECT NORTHEASTWARD FROM THE BASE
OF THE TROUGH TO THE SOUTHERN MISSOURI RIVER VALLEY BY 00Z THIS
EVENING. A DEEPENING 986 MB SURFACE CYCLONE OVER THE OKLAHOMA
PANHANDLE WILL LIKEWISE LIFT NORTHEASTWARD OVER THE COURSE OF THE
DAY AND BE SITUATED NEAR PRAIRIE DU CHIEN BY 00Z TONIGHT USING THE
GFS SOLUTION...WHICH IS HANDLING THE DEEPENING EVOLUTION OF THE LOW
THE BEST THIS MORNING. THIS WILL BRING A WIDE VARIETY OF WEATHER
ACROSS CENTRAL IOWA TODAY.
STARTING OUT THIS MORNING...A BROAD WARM FRONT CURRENTLY STRETCHES
FROM NEAR OMAHA TO DUBUQUE...WITH TEMPERATURES IN THE MID 30S NORTH
OF THE BOUNDARY TO MID 40S SOUTH. THIS BOUNDARY WILL TIGHTEN DURING
THE COURSE OF THE DAY AS THE LOW APPROACHES...WITH HIGHS RANGING
FROM THE MID 30S NORTHWEST TO NEAR 60 IN THE SOUTHEAST. AS THE LOW
BEGINS TO PULL EASTWARD AFTER 18Z...THIS WILL LIKEWISE PULL THE
BOUNDARY EASTWARD AS A COLD FRONT THIS AFTERNOON AND EVENING.
WIDESPREAD RAIN IS EXPANDING ACROSS THE AREA NOW AS STRONG MIDLEVEL
KINEMATIC/290-300 K ISENTROPIC FORCING INTENSIFIES. INITIAL BOUT OF
PRECIP EARLIER IN THE NIGHT TIED IN WITH A REGION OF THETA-E
ADVECTION HAD TO FIGHT A SUB 800 MB DRY LAYER...BUT THE COLUMN IS
RAPIDLY SATURATING AND PRECIP IS BEING REPORTED AT MULTIPLE SITES.
BEST MIDLEVEL FORCING AND DEEPEST MOISTURE WILL BE COINCIDENT IN THE
15-21Z TIMEFRAME AND HAVE KEPT THE MAX QPF AMOUNTS DURING THIS
WINDOW. PWATS OF 0.50 TO 0.75 INCHES ARE 2 TO 3 STANDARD DEVIATIONS
ABOVE NORMAL AND DAILY TOTAL RAINFALL AMOUNTS OF 0.50 TO 0.75 INCHES
ARE POSSIBLE. THIS WIDESPREAD RAIN WILL LEAD TO RISES IN AREA RIVERS
WHICH HAVE STILL NOT FULLY RECOVERED FROM THE RECORD SETTING DELUGE
A WEEK AND A HALF AGO.
AS THE UPPER LEVEL WAVE MATURES A DRY SLOT WILL WRAP NORTHWARD
ACROSS THE SOUTHERN AND EASTERN PORTIONS OF THE STATE BETWEEN 18 AND
00Z. CURRENT POP AND QPF GRIDS MAY BE A LITTLE CONSERVATIVE ON THE
TIMING OF THIS DRY SLOT OVER SOUTHERN IOWA...BUT GIVEN THE SLOWER
TRENDS OF RECENT MODEL RUNS...HAVE KEPT CATEGORICAL POPS OVER THE
SOUTH UNTIL 16-17Z. THIS DRY SLOT WILL ALSO RESULT IN STEEPENING MID
LEVEL LAPSE RATES AND INCREASING INSTABILITY OVER THE SOUTHEASTERN
PORTION OF THE CWA. RAP BUFR SOUNDINGS FROM OTTUMWA SHOW 300-500
J/KG OF MUCAPE DEVELOPING BETWEEN 18-20Z. 0-6 KM SHEAR VALUES OF 40
TO 50 KTS WILL BE MORE THAN CAPABLE OF MAINTAINING ANY THUNDERSTORMS
THAT DO DEVELOP IN THE WARM SECTOR EARLY THIS AFTERNOON. THE THREAT
FOR ORGANIZED AND SEVERE CONVECTION WILL BE CONFINED TO A VERY
NARROW AND CONDITIONAL WINDOW ACROSS THE FAR SOUTHEAST...AND WITH
STORM MOTIONS OF 40 TO 50 KTS TO THE NORTHEAST...THESE STORMS WILL
RAPIDLY EXIT THE CWA. THE MAIN THREAT WOULD BE LARGE HAIL GIVEN THE
LOW FREEZING LEVELS...BUT IF SOMEHOW ANY SOLAR INSOLATION WERE TO
TAKE PLACE AND THE STORMS DID GO SURFACE BASED...THE 35 KTS OF 0-1
KM SHEAR AND PROXIMITY TO THE SURFACE LOW WOULD SUPPORT TORNADOES.
AGAIN...THE THREAT FOR ANY SEVERE WEATHER...LET ALONE TORNADOES...IS
VERY CONDITIONAL AND LIMITED TO A SHORT WINDOW FROM AROUND 19-22Z.
NEXT ON THE DOCKET ARE WINDS ON THE BACKSIDE OF THE LOW. A
TIGHTENING PRESSURE GRADIENT AND STRONG PRESSURE RISE COUPLET
IMMEDIATELY FOLLOWING THE LOW WILL RESULT IN WINDS OF 20 TO 25 KTS
SUSTAINED WITH GUSTS OF 30 TO 35 KTS ACROSS SOUTHERN IOWA THROUGH
THE LATE AFTERNOON AND EVENING HOURS. DEFORMATION ZONE AND ELEVATED
FG ZONE WILL LINGER ACROSS THE WESTERN PORTIONS OF THE CWA AS THE
FRONTAL BOUNDARY SLIDES EASTWARD. PRECIP IN THIS ZONE WILL CHANGE
OVER TO SNOW DURING THE COURSE OF THE AFTERNOON AS COOLER AIR MOVES
IN...BUT KEPT SNOW AMOUNTS AROUND A HALF INCH OR LESS GIVEN THE LACK
OF ANY STRONG CAA AND NEAR SURFACE TEMPS STILL IN THE LOW TO MID
30S. ROADS WILL LIKELY JUST STAY WET WITH ACCUMULATIONS ON GRASSY
AREAS.
.LONG TERM /TONIGHT THROUGH TUESDAY/...
ISSUED AT 410 AM CST WED DEC 23 2015
THE PATTERN WILL BE QUITE ACTIVE THROUGH THE ENTIRE PERIOD...WITH
SOME TRAVEL IMPACTS EXPECTED DURING THE EXTENDED...BUT CONFIDENCE
IN DETAILS REMAINS LOW FOR A MULTITUDE OF REASONS. AT ONSET EXPECT
A FRONTOGENETICALLY FORCED DEFORMATION ZONE WITH DEEP VERTICAL
MOTION TO BE QUICKLY RETREATING TO THE NORTH AND EAST EARLY IN THE
EVENING. CONFIDENCE IN SNOW ACCUMS HAS INCREASED...AND DENDRITIC
GROWTH ZONE LIFT WILL BE QUITE STRONG FOR A PERIOD...BUT IT WILL
BE VERY BRIEF AND TRANSIENT. TOTAL ACCUMS WILL GENERALLY BE AN
INCH OR LESS NORTH AND WEST...BUT TOTALS MAY VARY A BIT IN EITHER
DIRECTION DUE TO MELTING ON PAVEMENT VS VEGETATION AND LOCALIZED
HIGHER RATES. ANYTHING TOWARD THE INCH RANGE WOULD BE FAR NORTH.
STRONG SUBSIDENCE WILL THEN SET IN BY NIGHT. MIXING WILL BE FAIRLY
SHALLOW BUT MSLP GRADIENT MAY STILL ALLOW FOR GUSTS TO REACH 35
MPH OR SO THROUGH AT LEAST MIDNIGHT NE.
SHORT WAVE RIDING STRONG NRN CA/OR JET WILL THEN REACH THE MO VALLEY
THU. FORCING AND MOISTURE EXTENT WILL BE QUITE VARIABLE...NEVER
REALLY APPROACHING SATURATION. THIS WILL RESULT IN ANY AMOUNTS
BEING QUITE LIGHT...AND PTYPE IN QUESTION DUE TO ONLY A SMALL
WINDOW OF ICE INTRODUCTION. THUS HAVE LOW CHANCES WITH BOTH LIGHT
SNOW OR FLURRIES...AND LIGHT FREEZING RAIN/SPRINKLES POSSIBLE.
SHOULD SEE A BRIEF BREAK IN PRECIP THU NIGHT BEFORE SHORT WAVES
REACH CA AND CONTINUE TO CARVE OUT WRN CONUS LONG WAVE TROUGH...AND
EVENTUAL CUTOFF. THIS SETS UP A PROLONGED PERIOD OF SWLY FLOW
ALOFT...AND INVERTED TROUGHINESS INTO THE MID MS VALLEY. AS THE
CLOSED LOW FORMS IN THE SW...A SHORT WAVE WILL SPLIT AND RIDE THE SW
FLOW INTO THE MO VALLEY EARLY IN THE WEEKEND. PRECIP CHANCES WILL
INCREASE SHARPLY FRI INTO FRI NIGHT. ALTHOUGH THE DEEPEST QG FORCING
WILL REMAIN JUST TO OUR NORTH AND WEST...THE H85/H7 FORCING IS
EXTREME WITH HIGH CONTRIBUTIONS FROM THETA-E ADVECTION AND
FRONTOGENESIS. SNOWFALL RATES OVER NRN IA MAY BRIEFLY BE QUITE HIGH
WITH LOW STABILITY. GFS TICKS OFF SOME MUCAPES AND...ALTHOUGH
FAIRLY ELEVATED...ALSO SHOWS NEGATIVE SAT EPV WHICH WOULD BE
EXPECTED WITH THE LOW STATIC STABILITY AND MUCAPE REFLECTION. THUS
HAVE AN INCH OR TWO OF SNOW ACCUMS POSSIBLE NORTH THROUGH 12Z SAT
WITH ADDITIONAL AMOUNTS POSSIBLE AFTER THAT TIME. THE WAVE THEN
MOVES AWAY LATER SAT WITH THE ATTENTION TURNING TOWARD THE
APPROACHING CUTOFF LOW. SOME POPS LINGER THROUGH THE
WEEKEND...ESPECIALLY SOUTH...BUT NEITHER THE FORCING OR MOISTURE
IS TOO IMPRESSIVE.
THE PROGRESSION OF THE CUTOFF LOW WILL LIKELY RESULT IN THE BIGGEST
TRAVEL IMPACT OF THE HOLIDAY TRAVEL SEASON...BUT DETAILS ARE FAR
FROM CLEAR CUT. THE ECMWF HAS BEEN FAIRLY CONSISTENT WITH ITS
FARTHER WEST AND LESS SNOWY TRACK...BUT VARIABLE IN TIME OVER
RECENT RUNS. THE GFS TRACK AND TIMING HAVE BEEN MORE
CONSISTENT...AND POINT TOWARD A WIND BLOW HEAVY SNOW EVENT...BUT
IS A FASTER OUTLIER VS THE SLOWER CANADIAN AND ECMWF. RATHER THAN
FOCUSING ON THE DETAILS THE MAIN TAKE HOME POINT FOR NOW WOULD
APPEAR TO BE A SIGNIFICANT SYSTEM WILL AFFECT HOLIDAY TRAVEL IN OR
NEAR IA SOMETIME AROUND MON OR MON NIGHT. FOR THE TIME BEING HAVE
EITHER RAIN OR SNOW IN THE FORECAST WITH LOW CONFIDENCE...BUT THE
ECMWF ALSO HINTS AT THE POSSIBILITY OF A FREEZING RAIN/ICING EVENT
NRN HALF WITH A NICE ELEVATED WARM LAYER ABOVE SUB FREEZING
SURFACE TEMPS AND A BRISK ELY WIND. WILL NEED TO CONTINUE TO
MONITOR FOR THE POTENTIAL FOR EITHER ICING OR SNOW. WHATEVER
OCCURS LOOKS TO BE GONE BY TUE NIGHT EVEN WITH THE SLOWER ECMWF
SOLUTION.
&&
.AVIATION...23/18Z
ISSUED AT 1147 AM CST WED DEC 23 2015
LOW PRESSURE WILL LIFT NE ACROSS TAF LOCATIONS. TAF LOCATIONS WILL
REMAIN IFR DUE TO CIGS AND VSBYS IN FOG. INSTABILITY WILL LIFT
ACROSS THE SE AND FAR E BRINGING A BRIEF WINDOW FOR TSRA ACROSS
THOSE LOCATIONS. SNOW POSSIBLE BRIEFLY ON THE BACK SIDE OF THE LOW
AFFECTING KFOD AND KMCW. AS THE LOW PULLS OUT AFT 22Z...WINDS WILL
INCREASE TO 20G28KTS AND BECOME WRLY.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...SKOW
LONG TERM...SMALL
AVIATION...FAB
AREA FORECAST DISCUSSION
NWS JACKSON KY
356 PM EST WED DEC 23 2015
.UPDATE...
ISSUED AT 217 PM EST WED DEC 23 2015
RAPIDLY MOVING SHOWERS HAVE PUSHED INTO THE SW PART OF THE JKL
FORECAST AREA OUT OF TN...WITH EVEN A FEW SPARSE LIGHTNING
STRIKES. HAVE UPDATED THE FORECAST TO ACCOUNT FOR THIS ACTIVITY
TO MAKE ITS WAY NE ACROSS THE REGION.
UPDATE ISSUED AT 1019 AM EST WED DEC 23 2015
SHOWERS ARE DIMINISHING LATE THIS MORNING AS THE AREA OF PRECIP
EXITS TO THE EAST. THERE IS A SIZABLE HOLE IN THE ACTIVITY
UPSTREAM TO OUR WEST AND SOUTHWEST. MODEL FORECAST SOUNDINGS
SUGGEST THIS WILL PERSIST OVER THE JKL FORECAST AREA AS IT
PROPAGATES THROUGH...WITH MID/UPPER LEVEL DRYING TAKING PLACE AS A
LOW LEVEL CAP PERSISTS. DEEP CONVECTION COULD BEGIN TO SHOW UP
FROM THE WEST BY THE END OF THE DAY.
UPDATE ISSUED AT 654 AM EST WED DEC 23 2015
SHOWERS NOW EXPANDING ACROSS THE AREA AS THE WARM FRONT LIFTS
NORTH. LOOKS LIKE MOST OF THE RAIN WILL OCCUR IN THE NEXT FEW
HOURS...BUT A FEW SHOWERS WILL REMAIN POSSIBLE INTO THE EARLY
AFTERNOON HOURS AS A MOIST ENVIRONMENT REMAINS OVER THE AREA.
LOOKS LIKE THE SEVERE STORMS SHOULD BE KNOCKING ON OUR DOOR
SHORTLY AFTER 9 PM THIS EVENING. OUR FORECAST GRAPHICAL TIMING
LOOKS EXCELLENT RIGHT NOW.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 343 AM EST WED DEC 23 2015
...SEVERE STORMS WITH DAMAGING WINDS POSSIBLE TONIGHT...
A RATHER ACTIVE...SPRING-LIKE PATTERN EXPECTED OVER THE NEXT 36
HOURS. PRESENTLY...A WARM FRONT IS LIFTING NORTH ACROSS TENNESSEE.
SOUTHEAST WINDS TO THE NORTH OF THE FRONT HAS KEPT MUCH OF EASTERN
KENTUCKY DRY OVERNIGHT. HOWEVER...THIS IS ABOUT TO CHANGE AS THE
FRONT CONTINUES TO PUSH NORTH THIS MORNING AND WINDS TURN MORE
SOUTHERLY. THE INITIAL SURGE OF MID LEVEL ISENTROPIC ASCENT HAS
GENERATED A LARGER POCKET OF RAINFALL OVER THE CUMBERLAND
PLATEAU...AND THIS RAIN WILL MOVE NORTH ACROSS OUR WESTERN
COUNTIES THROUGH 7 AM. INCREASED POPS TO CATEGORICAL WITH THIS
RAIN SPREADING NORTH. TO THE EAST...WE SHOULD REMAIN WITH VERY
LITTLE AS THE DOWNSLOPING CONTINUES TO EAT AWAY AT SHOWERS TRYING
TO PUSH NORTH. EVENTUALLY THE DRY AIR WILL BE OVERCOME...LIKELY
AROUND OR SHORTLY AFTER 7 AM...WITH SCATTERED SHOWERS PUSHING
NORTH ACROSS THE REGION THROUGH THE MORNING. HRRR HAS BEEN
CONSISTENT ON LINGERING SHOWERS INTO THE AFTERNOON...SO HAVE
KEPT POPS IN THE FORECAST THROUGH EARLY AFTERNOON. IT DOES APPEAR
WE SHOULD SEE A BETTER BREAK IN PRECIPITATION BY LATE AFTERNOON
THROUGH THE EARLY EVENING HOURS..AS SUBSIDENCE SPREADS IN AHEAD OF
THE APPROACHING COLD FRONT.
WITH THE FRONT APPROACHING THIS AFTERNOON...THE GRADIENT SHOULD
INCREASE AND WE WILL SEE GUSTY WINDS DEVELOP AREA WIDE. THE NAM
BUFKIT MOMENTUM TRANSFER EQUATION SUPPORTS 3O TO 35 MPH WIND
GUSTS...ESPECIALLY OUT ACROSS CENTRAL KENTUCKY...EXTENDING ACROSS
THE BLUEGRASS. WIND GUSTS UP TO 25 WILL REMAIN POSSIBLE TO THE
EAST. PUT IN A MENTION IN THE HWO OF THE GUSTY WINDS THIS
AFTERNOON.
FINALLY...MOVING ONTO THE SEVERE POTENTIAL TONIGHT. MODELS ARE
STILL NOT IN GREAT AGREEMENT ON OVERALL TIMING...AS A FEW OF THE
HI-RES MODELS SUPPORT AN EARLIER ROUND OF CONVECTION IN THE
EVENING...WHILE OTHERS HOLD OFF UNTIL OVERNIGHT. THUS...CONFIDENCE
IS HIGH ON THE THREAT FOR SEVERE STORMS OCCURRING TONIGHT...THERE
REMAINS CONSIDERABLE SPREAD ON WHETHER IT OCCURS MID TO LATE
EVENING OR AFTER MIDNIGHT. REGARDLESS OF TIMING...SHEAR GENERATED
WITH THE STRENGTH OF THE LOW LEVEL JET IS TREMENDOUS AND WILL
SUPPORT THE SEVERE STORM POTENTIAL. THE EXACT QUESTION IS HOW MUCH
INSTABILITY WILL BE PRESENT AS THE STORMS CROSS INTO EASTERN
KENTUCKY TONIGHT. NAM BUFKIT SOUNDINGS SHOW SOME POTENTIAL FOR
600-1000J/KG OF SBCAPE...WHICH IS MARGINAL...BUT COULD BE ENOUGH
TO ALLOW WINDS TO REACH THE SURFACE...ESPECIALLY IF WE END UP
DEALING WITH MORE LINE SEGMENTS. THUS...THE STORM PREDICTION
CENTER HAS EXPANDED THE ENHANCED RISK OF SEVERE STORMS INTO
CENTRAL KENTUCKY. IF WE DO END UP WITH A QLCS/LINE OF STORMS...
A SPIN UP TORNADO WOULD ALSO BE POSSIBLE ALONG THE LINE WITH SUCH
STRONG SHEAR NEARLY NORMAL TO THE ADVANCING STORMS. WILL CONTINUE
TO HIGHLIGHT DAMAGING WINDS/TORNADO THREAT IN THE HWO AND PLAN TO
DO A MORNING WEB BRIEFING TO HIGHLIGHT THE THREAT.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 356 PM EST WED DEC 23 2015
AT UPPER LEVELS...MODELS ARE IN GOOD AGREEMENT WITH THE AMPLIFIED
AND ACTIVE LONG WAVE PATTERN ACROSS THE CONUS THROUGH EARLY NEXT
WEEK. THIS IS DUE TO A BERMUDA HIGH SITTING OVER THE WESTERN
ATLANTIC GRADUALLY SHIFTING TOWARDS THE BAHAMAS BY EARLY NEXT
WEEK. AS THE HIGH PUSHES EAST...THE LONG WAVE PATTERN WILL
TRANSITION TO A SPLIT FLOW SETTING UP DEEP AND BROAD TROUGHING IN
THE WEST HALF OF THE NATION OVER THE HOLIDAY WEEKEND. A CUTOFF LOW
WILL DROP SOUTHEAST INTO TEXAS AND THEN SWING NORTHEAST INTO THE
MISSISSIPPI VALLEY BY EARLY NEXT WEEK...AND THEN EVENTUALLY LIFT
TOWARDS THE GREAT LAKES REGION BY MID WEEK. MODEL SOLUTIONS DIFFER
WITH THE CUTOFF LOW SO THERE IS LOW CONFIDENCE WITH THIS PORTION
OF THE FORECAST.
AT THE SFC...A STALLED FRONTAL BOUNDARY WILL BE LIFTING NORTHWARD
THROUGH OUR AREA FRIDAY MORNING BRINGING A RETURNED SURGE OF LOW
LEVEL MOISTURE. CONFIDENCE REGARDING HOW MUCH RAINFALL WE WILL SEE
FRIDAY INTO FRIDAY NIGHT CONTINUES TO BE ON THE LOW SIDE DUE TO
MODEL DIFFERENCES BETWEEN THE 12Z GFS AND ECMWF. THOUGH THERE WILL
BE PLENTY OF MOISTURE WITH PWATS NEAR 1.5 INCHES...WHICH IS WELL
ABOVE THE 90TH PERCENTILE ACCORDING TO CLIMATOLOGY. SO WILL
CONTINUE TO STICK CLOSE TO CR SUPERBLEND WITH POP CHANCES ON
FRIDAY.
BY SATURDAY MORNING...THE FRONT SHOULD BE SITUATED NORTH OF THE
AREA...OR JUST ON THE FRINGE OF OUR NORTHWEST COUNTIES. THIS
SHOULD ALLOW THINGS TO DRY OUT MAINLY IN OUR SOUTHEAST COUNTIES
FOR A PORTION OF THE WEEKEND...WITH LESSER POP CHANCES IN THE
OTHER PORTIONS OF THE FORECAST AREA. AS THE NEXT SFC WAVE
APPROACHES THE REGION ON MONDAY...RAIN WILL SWEEP ACROSS EASTERN
KENTUCKY AND PERSIST THROUGH TUESDAY MORNING. THE TIMING AND
PRECIP AMOUNTS DIFFER BETWEEN MODELS WITH THE GFS BEING THE FASTER
SOLUTION. THAT BEING SAID...DECIDED TO STAY CLOSE TO THE CR
SUPERBLEND...AND KEPT RAIN CHANCES IN THE FORECAST THROUGH LATE
TUESDAY TO ACCOUNT FOR THE SLOWER SOLUTIONS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 134 PM EST WED DEC 23 2015
VFR PREVAILED AT THE START OF THE PERIOD AND WILL PROBABLY LAST
INTO EARLY THIS EVENING. SOUTH WINDS MAY BE GUSTY AT TIMES THIS
AFTERNOON AND EVENING...WITH GUSTS OF 15 TO 25 MPH. THE STRONGEST
GUSTS ARE EXPECTED WEST OF THE FOOTHILLS. A FEW SHOWERS AND
THUNDERSTORMS COULD SHOW UP LATE IN THE DAY...BUT THEY ARE MORE
LIKELY TO HOLD OFF UNTIL TONIGHT. THE MOST LIKELY ARRIVAL TIME IN
WESTERN AREAS SUCH AS KSME AND KIOB IS BETWEEN ABOUT 03Z-
05Z...WITH PRECIPITATION THEN PROGRESSING EASTWARD ACROSS THE
REMAINDER OF THE STATE BY ABOUT 08Z. MVFR SHOULD ARRIVE SHORTLY
AFTER PRECIPITATION MOVES IN TONIGHT. ALSO...THUNDERSTORMS AND
THE HEAVIEST SHOWERS MAY CONTAIN WIND GUSTS IN EXCESS OF 40 MPH.
PRECIPITATION MAY LAST PAST DAYBREAK ON THURSDAY...ESPECIALLY IN
SOUTHEAST KY. MANY LOCATIONS MAY DETERIORATE TO IFR ON THURSDAY
MORNING...ESPECIALLY IN SOUTHEAST KY.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HAL
SHORT TERM...KAS
LONG TERM...JVM
AVIATION...HAL
AREA FORECAST DISCUSSION
NWS JACKSON KY
217 PM EST WED DEC 23 2015
.UPDATE...
ISSUED AT 217 PM EST WED DEC 23 2015
RAPIDLY MOVING SHOWERS HAVE PUSHED INTO THE SW PART OF THE JKL
FORECAST AREA OUT OF TN...WITH EVEN A FEW SPARSE LIGHTNING
STRIKES. HAVE UPDATED THE FORECAST TO ACCOUNT FOR THIS ACTIVITY
TO MAKE ITS WAY NE ACROSS THE REGION.
UPDATE ISSUED AT 1019 AM EST WED DEC 23 2015
SHOWERS ARE DIMINISHING LATE THIS MORNING AS THE AREA OF PRECIP
EXITS TO THE EAST. THERE IS A SIZABLE HOLE IN THE ACTIVITY
UPSTREAM TO OUR WEST AND SOUTHWEST. MODEL FORECAST SOUNDINGS
SUGGEST THIS WILL PERSIST OVER THE JKL FORECAST AREA AS IT
PROPAGATES THROUGH...WITH MID/UPPER LEVEL DRYING TAKING PLACE AS A
LOW LEVEL CAP PERSISTS. DEEP CONVECTION COULD BEGIN TO SHOW UP
FROM THE WEST BY THE END OF THE DAY.
UPDATE ISSUED AT 654 AM EST WED DEC 23 2015
SHOWERS NOW EXPANDING ACROSS THE AREA AS THE WARM FRONT LIFTS
NORTH. LOOKS LIKE MOST OF THE RAIN WILL OCCUR IN THE NEXT FEW
HOURS...BUT A FEW SHOWERS WILL REMAIN POSSIBLE INTO THE EARLY
AFTERNOON HOURS AS A MOIST ENVIRONMENT REMAINS OVER THE AREA.
LOOKS LIKE THE SEVERE STORMS SHOULD BE KNOCKING ON OUR DOOR
SHORTLY AFTER 9 PM THIS EVENING. OUR FORECAST GRAPHICAL TIMING
LOOKS EXCELLENT RIGHT NOW.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 343 AM EST WED DEC 23 2015
...SEVERE STORMS WITH DAMAGING WINDS POSSIBLE TONIGHT...
A RATHER ACTIVE...SPRING-LIKE PATTERN EXPECTED OVER THE NEXT 36
HOURS. PRESENTLY...A WARM FRONT IS LIFTING NORTH ACROSS TENNESSEE.
SOUTHEAST WINDS TO THE NORTH OF THE FRONT HAS KEPT MUCH OF EASTERN
KENTUCKY DRY OVERNIGHT. HOWEVER...THIS IS ABOUT TO CHANGE AS THE
FRONT CONTINUES TO PUSH NORTH THIS MORNING AND WINDS TURN MORE
SOUTHERLY. THE INITIAL SURGE OF MID LEVEL ISENTROPIC ASCENT HAS
GENERATED A LARGER POCKET OF RAINFALL OVER THE CUMBERLAND
PLATEAU...AND THIS RAIN WILL MOVE NORTH ACROSS OUR WESTERN
COUNTIES THROUGH 7 AM. INCREASED POPS TO CATEGORICAL WITH THIS
RAIN SPREADING NORTH. TO THE EAST...WE SHOULD REMAIN WITH VERY
LITTLE AS THE DOWNSLOPING CONTINUES TO EAT AWAY AT SHOWERS TRYING
TO PUSH NORTH. EVENTUALLY THE DRY AIR WILL BE OVERCOME...LIKELY
AROUND OR SHORTLY AFTER 7 AM...WITH SCATTERED SHOWERS PUSHING
NORTH ACROSS THE REGION THROUGH THE MORNING. HRRR HAS BEEN
CONSISTENT ON LINGERING SHOWERS INTO THE AFTERNOON...SO HAVE
KEPT POPS IN THE FORECAST THROUGH EARLY AFTERNOON. IT DOES APPEAR
WE SHOULD SEE A BETTER BREAK IN PRECIPITATION BY LATE AFTERNOON
THROUGH THE EARLY EVENING HOURS..AS SUBSIDENCE SPREADS IN AHEAD OF
THE APPROACHING COLD FRONT.
WITH THE FRONT APPROACHING THIS AFTERNOON...THE GRADIENT SHOULD
INCREASE AND WE WILL SEE GUSTY WINDS DEVELOP AREA WIDE. THE NAM
BUFKIT MOMENTUM TRANSFER EQUATION SUPPORTS 3O TO 35 MPH WIND
GUSTS...ESPECIALLY OUT ACROSS CENTRAL KENTUCKY...EXTENDING ACROSS
THE BLUEGRASS. WIND GUSTS UP TO 25 WILL REMAIN POSSIBLE TO THE
EAST. PUT IN A MENTION IN THE HWO OF THE GUSTY WINDS THIS
AFTERNOON.
FINALLY...MOVING ONTO THE SEVERE POTENTIAL TONIGHT. MODELS ARE
STILL NOT IN GREAT AGREEMENT ON OVERALL TIMING...AS A FEW OF THE
HI-RES MODELS SUPPORT AN EARLIER ROUND OF CONVECTION IN THE
EVENING...WHILE OTHERS HOLD OFF UNTIL OVERNIGHT. THUS...CONFIDENCE
IS HIGH ON THE THREAT FOR SEVERE STORMS OCCURRING TONIGHT...THERE
REMAINS CONSIDERABLE SPREAD ON WHETHER IT OCCURS MID TO LATE
EVENING OR AFTER MIDNIGHT. REGARDLESS OF TIMING...SHEAR GENERATED
WITH THE STRENGTH OF THE LOW LEVEL JET IS TREMENDOUS AND WILL
SUPPORT THE SEVERE STORM POTENTIAL. THE EXACT QUESTION IS HOW MUCH
INSTABILITY WILL BE PRESENT AS THE STORMS CROSS INTO EASTERN
KENTUCKY TONIGHT. NAM BUFKIT SOUNDINGS SHOW SOME POTENTIAL FOR
600-1000J/KG OF SBCAPE...WHICH IS MARGINAL...BUT COULD BE ENOUGH
TO ALLOW WINDS TO REACH THE SURFACE...ESPECIALLY IF WE END UP
DEALING WITH MORE LINE SEGMENTS. THUS...THE STORM PREDICTION
CENTER HAS EXPANDED THE ENHANCED RISK OF SEVERE STORMS INTO
CENTRAL KENTUCKY. IF WE DO END UP WITH A QLCS/LINE OF STORMS...
A SPIN UP TORNADO WOULD ALSO BE POSSIBLE ALONG THE LINE WITH SUCH
STRONG SHEAR NEARLY NORMAL TO THE ADVANCING STORMS. WILL CONTINUE
TO HIGHLIGHT DAMAGING WINDS/TORNADO THREAT IN THE HWO AND PLAN TO
DO A MORNING WEB BRIEFING TO HIGHLIGHT THE THREAT.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 359 AM EST WED DEC 23 2015
THE MODELS REMAIN IN GOOD GENERAL AGREEMENT WITH THE AMPLIFIED AND
ACTIVE LONG WAVE PATTERN THROUGH EARLY NEXT WEEK...AS THE SUMMER-
LIKE BERMUDA HIGH VERY GRADUALLY SHIFTS TOWARDS THE BAHAMAS BY
EARLY NEXT WEEK. MEANWHILE...DEEP AND BROAD TROUGHING IN THE
WESTERN HALF OF THE NATION TRANSITIONS TO SPLIT FLOW BY THE
HOLIDAY WEEKEND. A CUTOFF LOW WILL DROP SOUTHEAST INTO
TEXAS/MEXICO...AND THEN SWING NORTHEAST INTO THE PLAINS AND
EVENTUALLY GREAT LAKES/OHIO VALLEY REGIONS BY EARLY NEXT WEEK.
NEAR RECORD TO RECORD TEMPERATURES AT TIMES...ALONG WITH SEVERAL
ROUNDS OF WET WEATHER STILL LOOK IN THE OFFING FOR THE OHIO AND
TENNESSEE VALLEYS THROUGH THE PERIOD.
A FRONTAL BOUNDARY WILL BE STALLING ACROSS OUR AREA THURSDAY
NIGHT...WITH A SURGE OF LOW LEVEL MOISTURE COMING IN BY FRIDAY
MORNING. CONFIDENCE REGARDING HOW MUCH RAINFALL WE WILL SEE
FRIDAY INTO FRIDAY NIGHT AS THE FRONTAL BOUNDARY GRADUALLY LIFTS
NORTH AS A WARM FRONT CONTINUES TO BE ON THE LOW SIDE. PWATS ARE
VERY HIGH...HOWEVER MID AND UPPER LEVEL SUPPORT IS NOT THAT
IMPRESSIVE...SO AM NOT CONVINCED THAT THE MAJORITY OF THE MOISTURE
WILL BE TAPPED DESPITE THE AMPLE LOW LEVEL JET IN PLACE. AS
SUCH...HAVE CONTINUED TO KEEP THINGS GENERALIZED CONCERNING THE
FLOOD POTENTIAL UNTIL THERE IS BETTER MODEL AGREEMENT.
THE BAROCLINIC ZONE WILL SHIFT NORTH OF OUR AREA BY LATE SATURDAY
INTO SATURDAY NIGHT...LEADING TO LESSER CHANCES OF POPS ACROSS OUR
AREA. THE MODELS HAVE BEEN WAFFLING SUNDAY INTO MONDAY...WITH THE
ECMWF SUGGESTING A NORTHERN STREAM TROUGH HAVING ENOUGH PUSH TO
SEND THE BOUNDARY BACK ACROSS OUR AREA ON SUNDAY...AND THEN
HOLDING BACK THE NEXT FRONT UNTIL MAINLY TUESDAY. THE GFS HAS A
LITTLE BETTER CONTINUITY...KEEPING THE BOUNDARY JUST TO OUR
NORTH...UNTIL THE NEXT SURGE OF MOISTURE ARRIVES MONDAY NIGHT.
GIVEN THE UNCERTAINTY...STUCK FAIRLY CLOSE TO THE BLENDED
GUIDANCE...ALTHOUGH DID LINGER POPS A BIT LONGER INTO TUESDAY TO
ALLOW FOR A POTENTIAL SLOWER EXIT.
THE BEST CHANCE TO TEST RECORD HIGHS STILL LOOK TO BE SATURDAY AND
SUNDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 134 PM EST WED DEC 23 2015
VFR PREVAILED AT THE START OF THE PERIOD AND WILL PROBABLY LAST
INTO EARLY THIS EVENING. SOUTH WINDS MAY BE GUSTY AT TIMES THIS
AFTERNOON AND EVENING...WITH GUSTS OF 15 TO 25 MPH. THE STRONGEST
GUSTS ARE EXPECTED WEST OF THE FOOTHILLS. A FEW SHOWERS AND
THUNDERSTORMS COULD SHOW UP LATE IN THE DAY...BUT THEY ARE MORE
LIKELY TO HOLD OFF UNTIL TONIGHT. THE MOST LIKELY ARRIVAL TIME IN
WESTERN AREAS SUCH AS KSME AND KIOB IS BETWEEN ABOUT 03Z-
05Z...WITH PRECIPITATION THEN PROGRESSING EASTWARD ACROSS THE
REMAINDER OF THE STATE BY ABOUT 08Z. MVFR SHOULD ARRIVE SHORTLY
AFTER PRECIPITATION MOVES IN TONIGHT. ALSO...THUNDERSTORMS AND
THE HEAVIEST SHOWERS MAY CONTAIN WIND GUSTS IN EXCESS OF 40 MPH.
PRECIPITATION MAY LAST PAST DAYBREAK ON THURSDAY...ESPECIALLY IN
SOUTHEAST KY. MANY LOCATIONS MAY DETERIORATE TO IFR ON THURSDAY
MORNING...ESPECIALLY IN SOUTHEAST KY.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HAL
SHORT TERM...KAS
LONG TERM...GEOGERIAN
AVIATION...HAL
AREA FORECAST DISCUSSION
NWS JACKSON KY
134 PM EST WED DEC 23 2015
.UPDATE...
ISSUED AT 1019 AM EST WED DEC 23 2015
SHOWERS ARE DIMINISHING LATE THIS MORNING AS THE AREA OF PRECIP
EXITS TO THE EAST. THERE IS A SIZABLE HOLE IN THE ACTIVITY
UPSTREAM TO OUR WEST AND SOUTHWEST. MODEL FORECAST SOUNDINGS
SUGGEST THIS WILL PERSIST OVER THE JKL FORECAST AREA AS IT
PROPAGATES THROUGH...WITH MID/UPPER LEVEL DRYING TAKING PLACE AS A
LOW LEVEL CAP PERSISTS. DEEP CONVECTION COULD BEGIN TO SHOW UP
FROM THE WEST BY THE END OF THE DAY.
UPDATE ISSUED AT 654 AM EST WED DEC 23 2015
SHOWERS NOW EXPANDING ACROSS THE AREA AS THE WARM FRONT LIFTS
NORTH. LOOKS LIKE MOST OF THE RAIN WILL OCCUR IN THE NEXT FEW
HOURS...BUT A FEW SHOWERS WILL REMAIN POSSIBLE INTO THE EARLY
AFTERNOON HOURS AS A MOIST ENVIRONMENT REMAINS OVER THE AREA.
LOOKS LIKE THE SEVERE STORMS SHOULD BE KNOCKING ON OUR DOOR
SHORTLY AFTER 9 PM THIS EVENING. OUR FORECAST GRAPHICAL TIMING
LOOKS EXCELLENT RIGHT NOW.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 343 AM EST WED DEC 23 2015
...SEVERE STORMS WITH DAMAGING WINDS POSSIBLE TONIGHT...
A RATHER ACTIVE...SPRING-LIKE PATTERN EXPECTED OVER THE NEXT 36
HOURS. PRESENTLY...A WARM FRONT IS LIFTING NORTH ACROSS TENNESSEE.
SOUTHEAST WINDS TO THE NORTH OF THE FRONT HAS KEPT MUCH OF EASTERN
KENTUCKY DRY OVERNIGHT. HOWEVER...THIS IS ABOUT TO CHANGE AS THE
FRONT CONTINUES TO PUSH NORTH THIS MORNING AND WINDS TURN MORE
SOUTHERLY. THE INITIAL SURGE OF MID LEVEL ISENTROPIC ASCENT HAS
GENERATED A LARGER POCKET OF RAINFALL OVER THE CUMBERLAND
PLATEAU...AND THIS RAIN WILL MOVE NORTH ACROSS OUR WESTERN
COUNTIES THROUGH 7 AM. INCREASED POPS TO CATEGORICAL WITH THIS
RAIN SPREADING NORTH. TO THE EAST...WE SHOULD REMAIN WITH VERY
LITTLE AS THE DOWNSLOPING CONTINUES TO EAT AWAY AT SHOWERS TRYING
TO PUSH NORTH. EVENTUALLY THE DRY AIR WILL BE OVERCOME...LIKELY
AROUND OR SHORTLY AFTER 7 AM...WITH SCATTERED SHOWERS PUSHING
NORTH ACROSS THE REGION THROUGH THE MORNING. HRRR HAS BEEN
CONSISTENT ON LINGERING SHOWERS INTO THE AFTERNOON...SO HAVE
KEPT POPS IN THE FORECAST THROUGH EARLY AFTERNOON. IT DOES APPEAR
WE SHOULD SEE A BETTER BREAK IN PRECIPITATION BY LATE AFTERNOON
THROUGH THE EARLY EVENING HOURS..AS SUBSIDENCE SPREADS IN AHEAD OF
THE APPROACHING COLD FRONT.
WITH THE FRONT APPROACHING THIS AFTERNOON...THE GRADIENT SHOULD
INCREASE AND WE WILL SEE GUSTY WINDS DEVELOP AREA WIDE. THE NAM
BUFKIT MOMENTUM TRANSFER EQUATION SUPPORTS 3O TO 35 MPH WIND
GUSTS...ESPECIALLY OUT ACROSS CENTRAL KENTUCKY...EXTENDING ACROSS
THE BLUEGRASS. WIND GUSTS UP TO 25 WILL REMAIN POSSIBLE TO THE
EAST. PUT IN A MENTION IN THE HWO OF THE GUSTY WINDS THIS
AFTERNOON.
FINALLY...MOVING ONTO THE SEVERE POTENTIAL TONIGHT. MODELS ARE
STILL NOT IN GREAT AGREEMENT ON OVERALL TIMING...AS A FEW OF THE
HI-RES MODELS SUPPORT AN EARLIER ROUND OF CONVECTION IN THE
EVENING...WHILE OTHERS HOLD OFF UNTIL OVERNIGHT. THUS...CONFIDENCE
IS HIGH ON THE THREAT FOR SEVERE STORMS OCCURRING TONIGHT...THERE
REMAINS CONSIDERABLE SPREAD ON WHETHER IT OCCURS MID TO LATE
EVENING OR AFTER MIDNIGHT. REGARDLESS OF TIMING...SHEAR GENERATED
WITH THE STRENGTH OF THE LOW LEVEL JET IS TREMENDOUS AND WILL
SUPPORT THE SEVERE STORM POTENTIAL. THE EXACT QUESTION IS HOW MUCH
INSTABILITY WILL BE PRESENT AS THE STORMS CROSS INTO EASTERN
KENTUCKY TONIGHT. NAM BUFKIT SOUNDINGS SHOW SOME POTENTIAL FOR
600-1000J/KG OF SBCAPE...WHICH IS MARGINAL...BUT COULD BE ENOUGH
TO ALLOW WINDS TO REACH THE SURFACE...ESPECIALLY IF WE END UP
DEALING WITH MORE LINE SEGMENTS. THUS...THE STORM PREDICTION
CENTER HAS EXPANDED THE ENHANCED RISK OF SEVERE STORMS INTO
CENTRAL KENTUCKY. IF WE DO END UP WITH A QLCS/LINE OF STORMS...
A SPIN UP TORNADO WOULD ALSO BE POSSIBLE ALONG THE LINE WITH SUCH
STRONG SHEAR NEARLY NORMAL TO THE ADVANCING STORMS. WILL CONTINUE
TO HIGHLIGHT DAMAGING WINDS/TORNADO THREAT IN THE HWO AND PLAN TO
DO A MORNING WEB BRIEFING TO HIGHLIGHT THE THREAT.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 359 AM EST WED DEC 23 2015
THE MODELS REMAIN IN GOOD GENERAL AGREEMENT WITH THE AMPLIFIED AND
ACTIVE LONG WAVE PATTERN THROUGH EARLY NEXT WEEK...AS THE SUMMER-
LIKE BERMUDA HIGH VERY GRADUALLY SHIFTS TOWARDS THE BAHAMAS BY
EARLY NEXT WEEK. MEANWHILE...DEEP AND BROAD TROUGHING IN THE
WESTERN HALF OF THE NATION TRANSITIONS TO SPLIT FLOW BY THE
HOLIDAY WEEKEND. A CUTOFF LOW WILL DROP SOUTHEAST INTO
TEXAS/MEXICO...AND THEN SWING NORTHEAST INTO THE PLAINS AND
EVENTUALLY GREAT LAKES/OHIO VALLEY REGIONS BY EARLY NEXT WEEK.
NEAR RECORD TO RECORD TEMPERATURES AT TIMES...ALONG WITH SEVERAL
ROUNDS OF WET WEATHER STILL LOOK IN THE OFFING FOR THE OHIO AND
TENNESSEE VALLEYS THROUGH THE PERIOD.
A FRONTAL BOUNDARY WILL BE STALLING ACROSS OUR AREA THURSDAY
NIGHT...WITH A SURGE OF LOW LEVEL MOISTURE COMING IN BY FRIDAY
MORNING. CONFIDENCE REGARDING HOW MUCH RAINFALL WE WILL SEE
FRIDAY INTO FRIDAY NIGHT AS THE FRONTAL BOUNDARY GRADUALLY LIFTS
NORTH AS A WARM FRONT CONTINUES TO BE ON THE LOW SIDE. PWATS ARE
VERY HIGH...HOWEVER MID AND UPPER LEVEL SUPPORT IS NOT THAT
IMPRESSIVE...SO AM NOT CONVINCED THAT THE MAJORITY OF THE MOISTURE
WILL BE TAPPED DESPITE THE AMPLE LOW LEVEL JET IN PLACE. AS
SUCH...HAVE CONTINUED TO KEEP THINGS GENERALIZED CONCERNING THE
FLOOD POTENTIAL UNTIL THERE IS BETTER MODEL AGREEMENT.
THE BAROCLINIC ZONE WILL SHIFT NORTH OF OUR AREA BY LATE SATURDAY
INTO SATURDAY NIGHT...LEADING TO LESSER CHANCES OF POPS ACROSS OUR
AREA. THE MODELS HAVE BEEN WAFFLING SUNDAY INTO MONDAY...WITH THE
ECMWF SUGGESTING A NORTHERN STREAM TROUGH HAVING ENOUGH PUSH TO
SEND THE BOUNDARY BACK ACROSS OUR AREA ON SUNDAY...AND THEN
HOLDING BACK THE NEXT FRONT UNTIL MAINLY TUESDAY. THE GFS HAS A
LITTLE BETTER CONTINUITY...KEEPING THE BOUNDARY JUST TO OUR
NORTH...UNTIL THE NEXT SURGE OF MOISTURE ARRIVES MONDAY NIGHT.
GIVEN THE UNCERTAINTY...STUCK FAIRLY CLOSE TO THE BLENDED
GUIDANCE...ALTHOUGH DID LINGER POPS A BIT LONGER INTO TUESDAY TO
ALLOW FOR A POTENTIAL SLOWER EXIT.
THE BEST CHANCE TO TEST RECORD HIGHS STILL LOOK TO BE SATURDAY AND
SUNDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 134 PM EST WED DEC 23 2015
VFR PREVAILED AT THE START OF THE PERIOD AND WILL PROBABLY LAST
INTO EARLY THIS EVENING. SOUTH WINDS MAY BE GUSTY AT TIMES THIS
AFTERNOON AND EVENING...WITH GUSTS OF 15 TO 25 MPH. THE STRONGEST
GUSTS ARE EXPECTED WEST OF THE FOOTHILLS. A FEW SHOWERS AND
THUNDERSTORMS COULD SHOW UP LATE IN THE DAY...BUT THEY ARE MORE
LIKELY TO HOLD OFF UNTIL TONIGHT. THE MOST LIKELY ARRIVAL TIME IN
WESTERN AREAS SUCH AS KSME AND KIOB IS BETWEEN ABOUT 03Z-
05Z...WITH PRECIPITATION THEN PROGRESSING EASTWARD ACROSS THE
REMAINDER OF THE STATE BY ABOUT 08Z. MVFR SHOULD ARRIVE SHORTLY
AFTER PRECIPITATION MOVES IN TONIGHT. ALSO...THUNDERSTORMS AND
THE HEAVIEST SHOWERS MAY CONTAIN WIND GUSTS IN EXCESS OF 40 MPH.
PRECIPITATION MAY LAST PAST DAYBREAK ON THURSDAY...ESPECIALLY IN
SOUTHEAST KY. MANY LOCATIONS MAY DETERIORATE TO IFR ON THURSDAY
MORNING...ESPECIALLY IN SOUTHEAST KY.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HAL/KAS
SHORT TERM...KAS
LONG TERM...GEOGERIAN
AVIATION...HAL
AREA FORECAST DISCUSSION
NWS NEW ORLEANS LA
1243 PM CST WED DEC 23 2015
...18Z SOUNDING DISCUSSION...
INHIBITION IN THE LOW LEVELS HAS MOSTLY BEEN ERODED DESPITE LOW
CLOUDS/MARINE LAYER HANGING OVER MUCH OF THE AREA. VERY MOIST AND
UNSTABLE ATMOSPHERE IS IN PLACE WITH SBCAPE OF 2300 J/KG AND
PRECIPITABLE WATER VALUE OF 1.64 INCHES NOW. THERE HAVE BEEN SOME
BREAKS IN THE CLOUDS MAINLY SOUTH OF THE TIDAL LAKES THIS MORNING
THAT HAVE BOOSTED TEMPERATURES INTO THE UPPER 70S TO NEAR 80 AS OF
NOON. WHILE WE HAVE LOST SOME DIRECTIONAL SHEAR AS WINDS AT/NEAR
THE SURFACE ARE NOW SOUTHERLY INSTEAD OF SOUTHEASTERLY...SPEED
SHEAR IS IMPRESSIVE. WINDS OF 50 KNOTS WERE OBSERVED AT 2000
FEET...A STRONG LOW LEVEL WIND. 0-1KM AND 0-3KM SRH VALUES ARE
OVER 500 M2/S2...WHICH IS QUITE SUPPORTIVE OF SEVERE POTENTIAL.
SOME NEGATIVE FACTORS TO THE SET UP ARE THE LOW CLOUDS/MARINE
LAYER ALREADY MENTIONED EARLIER LIMITING SURFACE HEATING.
DOWNDRAFT CAPE HAS DECREASED FURTHER WHICH WOULD SUGGEST EVEN LESS
LIKELIHOOD OF SEVERE DOWNBURST WINDS. IF WE ARE ABLE TO MIX IN
SOME DRIER AIR...WHICH ISN`T OUT OF THE QUESTION WITH STRONG LOW
LEVEL WINDS...WE MAY BE ABLE TO MIX DOWN STRONGER GUSTS TO THE
SURFACE. FREEZING LEVEL HAS INCREASED BY ABOUT 400 FEET
SUGGESTING LESSER POTENTIAL OF SEVERE HAIL. LOCAL CHAP /CONVECTIVE
HAZARD ASSESSMENT PROGRAM/ METHOD RUNNING OFF AN UNMODIFIED
SOUNDING PROVIDES LITTLE IN THE WAY OF SEVERE WEATHER. IF WE
MODIFY FOR ANTICIPATED UPPER LEVEL DYNAMICS...RICKS INDEX DOES NOT
CHANGE MUCH AND REMAINS UNDER SEVERE LEVELS WITH SUBSEVERE WIND
GUST POTENTIAL OF 30 KNOTS. THE ONE THING CHAP DOES PING ON IS
POTENTIAL FOR HIGH RAINFALL RATES.
WE CONTINUE TO WATCH CONVECTIVE TRENDS OVER WESTERN
LOUISIANA...WHICH MAY HOLD THE BEST POTENTIAL FOR ANY SEVERE
WEATHER. THIS HINGES ON DAYTIME HEATING...WHICH HAS BEEN LIMITED
SO FAR.
18Z BALLOON INFO: THE BALLOON`S ASCENT LASTED 94 MINUTES AND
TRAVELED 88 MILES DOWNRANGE FROM THE OFFICE BURSTING OVER VERNAL
AT A HEIGHT OF 20.2 MILES ABOVE THE GROUND.
ANSORGE
&&
.PREV DISCUSSION... /ISSUED 900 AM CST WED DEC 23 2015/
UPDATE...
OVERALL CONVECTIVE COVERAGE HAS DECREASED THIS MORNING AS THE
REGION HAS STABALIZED A BIT IN THE WAKE OF THE RAINFALL THAT
OCCURRED EARLIER TODAY. GIVEN THIS TREND...HAVE LOWERED POPS FOR
THE FORECAST AREA THROUGH THE EARLY AFTERNOON HOURS INTO THE
CHANCE RANGE FROM CATEGORICAL. HOWEVER...ANOTHER ROUND OF
CONVECTIVE DEVELOPMENT STILL LOOKS LIKELY FROM MID-AFTERNOON
THROUGH THE EVENING HOURS AS THE ATMOSPHERE WARMS AND TURNS MORE
UNSTABLE. ADDITIONALLY...ANOTHER UPPER LEVEL IMPULSE OF INCREASED
VORTICITY AND OMEGA WILL SLIDE THROUGH THE LOWER MISSISSIPPI
VALLEY DURING THE AFTERNOON HOURS. THIS INCREASE IN LIFT ALOFT
SHOULD PROVIDE ENOUGH OF A CATALYST TO FIRE OFF ANOTHER ROUND OF
SHOWERS AND THUNDERSTORMS. HAVE LIKELY POPS IN PLACE FOR THE LATE
AFTERNOON AND EVENING HOURS TO REFLECT THIS RISK. OUTSIDE OF THE
POP ADJUSTMENTS...NO OTHER FORECAST CHANGES WERE MADE AT THIS
TIME. 32
PREV DISCUSSION... /ISSUED 758 AM CST WED DEC 23 2015/
.SOUNDING DISCUSSION...
BOTTOM LINE UP FRONT...ALL MODES OF SEVERE WEATHER REMAIN POSSIBLE
TODAY. A VERY MOIST ATMOSPHERE WAS SAMPLED THIS MORNING WITH A
PRECIPITABLE WATER VALUE OF 1.74 INCHES. THIS IS 2 STANDARD
DEVIATIONS ABOVE NORMAL AND A RECORD VALUE FOR THIS DATE/TIME.
MOST UNSTABLE CAPE OF ABOUT 1200 J/KG EXISTS WITH INHIBITION IN
THE FORM OF A CAPPING INVERSION. ASSUMING LOW CLOUDS AND FOG
DISSIPATE AND WE HAVE SOME SURFACE HEATING...THIS CAPPING
INVERSION SHOULD ERODE. WITH QUITE A BIT OF MOISTURE IN THE LOW-
LEVELS...THE DOWNDRAFT CAPE IS NOT IN THE OPTIMUM RANGE FOR
DAMAGING STRAIGHT LINE WINDS. THIS MAY CHANGE IF DRIER AIR MIXES
DOWN AND WINDS BECOME MORE UNIDIRECTIONAL. THE FREEZING LEVEL IS
NEAR 13000 FEET WHICH IS HIGH...BUT THERE WAS A REPORT EARLIER IN
THE NIGHT OF 1.25 INCH DIAMETER HAIL IN ASCENSION PARISH. 0-1KM
SRH AND 0-3KM SRH IS IMPRESSIVE AT 200 AND 340 M2/S2 RESPECTIVELY.
WINDS ARE FROM THE SOUTHEAST AT THE SURFACE AND THEN ARE
PREDOMINATELY FROM THE SOUTHWEST. SO THERE IS LOW LEVEL
DIRECTIONAL SHEAR CURRENTLY. THERE IS ALSO SOME SPEED SHEAR WITH
950MB AT 15 KNOTS...850MB AT 33 KNOTS...700MB AT 51 KNOTS...500MB
IS AT 58 KNOTS. A PEAK WIND SPEED OF 103 KNOTS WAS AT 39000 FEET
WITH A STORM TOP WIND SPEED NEAR 48000 FEET OF 72 KNOTS.
SPC HAS REQUESTED AN 18Z SOUNDING IN SUPPORT OF SEVERE WEATHER
OPERATIONS.
12Z BALLOON INFO: A SUCCESSFUL FLIGHT LASTING 85 MINUTES AND
REACHING A HEIGHT OF 14.8 MILES ABOVE THE GROUND. THE BALLOON
BURST OVER NEELY 84 MILES DOWNRANGE FROM THE OFFICE.
ANSORGE
PREV DISCUSSION... /ISSUED 406 AM CST WED DEC 23 2015/
SHORT TERM... ACTIVE CONDITIONS ONGOING ACROSS THE FORECAST AREA
THIS MORNING. LOCAL VAD WIND PROFILE SHOWS THAT LOW LEVEL WINDS HAVE
INCREASES SUBSTANTIALLY OVER THE LAST FEW HOURS WITH SE FLOW OF 30
KNOTS AT THE LOWEST OBS OF 1KFT AND VEERING TO SW WHILE INCREASING
TO 50KTS IN THE MID LEVELS. THIS IS THE PRIMARY REASON FOR THE
RECENT RAMP UP OF STRONG/SEVERE THUNDERSTORMS EARLY THIS MORNING.
HAVE RECEIVED 1 REPORT OF HAIL AND SEVERAL CELLS HAVE BROAD
ROTATION...INDICATIVE OF INCREASING SRH. THIS IS ALL HAPPENING
DESPITE BEING WITHIN A MARINE LAYER. THE TREND OF ACTIVE WEATHER
WITH THE POTENTIAL FOR A FEW CELLS PRODUCING HAIL OR A TORNADO WILL
CONTINUE THROUGH THE REST OF THE EARLY MORNING HOURS. THE BULK OF
STRONGER STORMS WILL SHIFT NORTHEAST AFTER SUNRISE AS SHORT WAVE
VORTMAX DOES SO AS WELL.
MOISTURE LEVELS REMAIN VERY HIGH ACROSS THE CENTRAL GULF COAST THIS
MORNING WITH THE 00Z SOUNDING FROM YESTERDAY AFTERNOON HAVING A
PRECIP WATER VALUE OF AROUND 1.7 INCHES WHICH IS RIGHT AT THE
CLIMATOLOGY MAX PER SPC SOUNDING INFO. BROAD LONG WAVE TROUGH IS
ALREADY IN PLACE OVER THE WESTERN HALF OF THE COUNTRY. AN EMBEDDED
WAVE WILL DIG AND SWING NEGATIVE OVER THE CENTRAL PLAINS TODAY. DOWN
AT THE SURFACE A LOW ON THE LEESIDE OF THE ROCKIES WILL BE RACING
NORTHEAST ACROSS THE CENTRAL MISSISSIPPI VALLEY. SURFACE PRESSURES
IN THE CWA WILL BE SLOWLY FALLING DURING THE DAY WITH A MINIMUM OF
APPROACHING 1000MB BY NOON BASED ON RUC OUTPUT. TIGHTENING OF THE
PRESSURE GRADIENT WILL INCREASE SURFACE WINDS INTO THE 15 TO 25
MPH RANGE. THIS SHOULD DO 2 THINGS...TRANSPORT OFFSHORE 70+DEGREE
DEWPOINTS FURTHER INLAND AS WELL AS INCREASE LOW LEVEL WIND SHEAR
SUBSTANTIALLY. HELICITY LIKELY TO FALL SOME AS WIND DIRECTION
BECOMES MORE CLOSELY ORIENTED TO THE MEAN FLOW OR MORE SOUTH TO
SOUTH WEST RATHER THAN CURRENT SOUTHEAST DIRECTION. PRESUMING THAT
SFC TEMPS DO REACH MID/UPPER 70S WHILE THESE DEWPOINTS
RISE...BUOYANCY AND INSTABILITY WILL SHOOT UP DURING THE DAY. BOTH
GFS AND NAM BUFR SOUNDINGS STILL SHOW SB AND PARCEL CAPE VALUES
WELL OVER 2000 J/KG AND MU CAPE UP TO 1500 J/KG ALL OVER THE CWA.
SPEED SHEAR LOOKING TO BE 40 TO 50 KNOTS IN THE BOUNDARY LAYER
WHICH IS PLENTY STRONG TO SUSTAIN SUPERCELLS. THUS THE POTENTIAL
FOR SEVERE WEATHER WILL DEFINITELY BE THERE TODAY. ALL MODES OF
SEVERE WEATHER ARE POSSIBLE. STILL OF CONCERN IS IF SFC TEMPS DONT
WARM ENOUGH... WILL JUST HAVE THE DYNAMICS. TOO STRONG OF A WARM
NOSE IN THE LOWER LEVELS COULD CAP THINGS AS WELL REGARDLESS...THE
POTENTIAL IS DEFINITELY THERE AND WARRANTS THE SLIGHT RISK AT THE
LEAST FOR THE ENTIRE CWA.
LONG TERM... RESIDUAL SURFACE BOUNDARY WILL BE THE FOCUS FOR
CONVECTION ON THURSDAY. AMPLE MOISTURE STILL LEFT IN THE AREA SHOULD
HAVE NO PROBLEM DEVELOPING INTO SHOWERS WITH POSSIBLY A FEW
THUNDERSTORMS. MUCH WEAKER WINDS IN THE COLUMN WILL LIMIT
ORGANIZATION OF STORMS BUT WONT BE SHORT OF INSTABILITY.
COVERAGE SHOULD STILL BE 50 TO 70 PERCENT FOR THE MOST PART.
CHRISTMAS DAY SHOULD BEGIN THE DOWNWARD TREND OF POPS AS UPPER LEVEL
RIDGE CENTERED OVER THE WESTERN ATLANTIC BUILDS BACK WESTWARD ACROSS
THE CWA. DESPITE THIS DECREASE IN COVERAGE...STILL PROBABLY LOOKING
AT 20 TO 30 PERCENT RAIN CHANCE. NO CHANCE IN THE TEMP FORECAST AND
EXPECTING NEAR RECORD MAX TEMPS AND RECORD HIGH LOWS. SADLY...THERE
IS A ZERO PERCENT CHANCE FOR A WHITE CHRISTMAS.
POPS TO FALL EVEN MORE DOWN INTO THE SLIGHT CHANCE CATEGORY THIS
WEEKEND AS THE RIDGE SHIFTS THE SHEAR ZONE FURTHER NORTH AND WEST.
GFS AND ECMWF BOTH CLOSE OFF A LOW IN THE DESERT SOUTHWEST AND
TRACKS EAST BEFORE SWINGING NE OVER THE CENTRAL PLAINS ENDING THE
WEEKEND. THIS WOULD BRING A LINE OF SHOWERS AND STORMS MOVING THRU
SOME TIME BETWEEN SUNDAY NIGHT AND MONDAY NIGHT DEPENDING ON MODEL
TIMING. NUDGED THE POPS TO THE SLOWER SOLUTION AS THE FASTER GFS IS
CLOSER TO AN OUTLIER SIDE OF THINGS.
MEFFER
AVIATION... SEVERE WEATHER CAME IN A LITTLE EARLIER TODAY THAN
EXPECTED. WILL KEEP THAT THREAT GOING THROUGH THE DAY BUT EXPECT A
REPRIEVE FOR SEVERAL HOURS AFTER DAYLIGHT TODAY. ANOTHER ROUND WILL
BE POSSIBLE THIS AFTERNOON BUT WILL HAVE TO SEE HOW THIS SHAPES UP.
CEILINGS WILL REMAIN FROM OVC020 TO OVC030 TODAY AND TONIGHT. RAIN
WILL ALSO CEASE FOR A WHILE TODAY AND WILL SHOW THIS IN THE 12Z TAF
PACKAGE.
WILL TAKE ANOTHER LOOK AT WX IN TAF SET LATER THIS MORNING.
MARINE... AS UPPER SYSTEM SWINGS THROUGH THE MIDDLE MISSISSIPPI
RIVER VALLEY TODAY...PRESSURE GRADIENT WILL TIGHTEN AND SMALL CRAFT
ADVISORIES AND EXERCISE CAUTION HEADLINES HAVE BEEN ISSUED AHEAD OF
THE SYSTEM. THIS SHOULD BE SOMEWHAT SHORT LIVED AS WINDS SUBSIDE
TONIGHT. NEXT PERIOD OF HEADLINES WILL BE EXERCISE CAUTION HEADLINES
OVER THE WEEKEND AS ONSHORE FLOW AGAIN STRENGTHENS.
DECISION SUPPORT...
DSS CODE....BLUE.
DEPLOYED...NONE.
ACTIVATION...NONE.
ACTIVITIES...MONITORING CONVECTIVE TRENDS.
DECISION SUPPORT SERVICES (DSS) CODE LEGEND
GREEN = NO WEATHER IMPACTS THAT REQUIRE ACTION
BLUE = LONG FUSED WATCH/WARNING/ADVISORY IN EFFECT OR HIGH
VISIBILITY EVENT
YELLOW = HEIGHTENED IMPACTS WITH SHORT FUSED WATCH/WARNING/ADVISORY
ISSUANCES; RADAR SUPPORT
ORANGE = HIGH IMPACTS - SLIGHT TO MODERATE RISK SEVERE; NEARBY
TROPICAL EVENTS; HAZMAT OR OTHER LARGE EPISODES
RED = FULL ENGAGEMENT FOR MODERATE RISK SVR AND/OR DIRECT
TROPICAL THREATS; EVENTS OF NATIONAL SIGNIFICANCE
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 78 64 77 68 / 90 70 60 40
BTR 79 65 79 70 / 80 70 50 30
ASD 75 67 76 68 / 90 70 70 30
MSY 78 69 76 69 / 80 70 70 30
GPT 73 68 74 68 / 90 70 70 30
PQL 74 69 74 68 / 80 70 70 30
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 6 PM CST THIS EVENING FOR GMZ536-538-
550-552-555-557-570-572-575-577.
MS...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 6 PM CST THIS EVENING FOR GMZ538-550-
552-555-557-570-572-575-577.
&&
$$
AREA FORECAST DISCUSSION
NWS NEW ORLEANS LA
1210 PM CST WED DEC 23 2015
.MARINE...
GRADIENT FLOW HAS INCREASED MORE THAN ORIGINALLY ANTICIPATED
ACROSS THE SOUNDS AND LAKES THIS MORNING. AS A RESULT...SOUTHERLY
WINDS ARE IN SMALL CRAFT ADVISORY RANGE OF 20 TO 25 KNOTS AND THE
SMALL CRAFT EXERCISE CAUTION FLAGS HAVE BEEN UPGRADED TO ADVISORY
FLAGS. THESE STRONGER WINDS SHOULD PERSIST THROUGH THE AFTERNOON
HOURS IN ADVANCE OF A DEEPENING LOW PRESSURE SYSTEM OVER THE
MIDWESTERN STATES. THE GRADIENT FLOW SHOULD RELAX SOMEWHAT TONIGHT
AS THE LOW PULLS TO THE NORTHEAST AND A FRONTAL BOUNDARY STALLS
OVER THE REGION. 32
&&
.PREV DISCUSSION... /ISSUED 900 AM CST WED DEC 23 2015/
UPDATE...
OVERALL CONVECTIVE COVERAGE HAS DECREASED THIS MORNING AS THE
REGION HAS STABALIZED A BIT IN THE WAKE OF THE RAINFALL THAT
OCCURRED EARLIER TODAY. GIVEN THIS TREND...HAVE LOWERED POPS FOR
THE FORECAST AREA THROUGH THE EARLY AFTERNOON HOURS INTO THE
CHANCE RANGE FROM CATEGORICAL. HOWEVER...ANOTHER ROUND OF
CONVECTIVE DEVELOPMENT STILL LOOKS LIKELY FROM MID-AFTERNOON
THROUGH THE EVENING HOURS AS THE ATMOSPHERE WARMS AND TURNS MORE
UNSTABLE. ADDITIONALLY...ANOTHER UPPER LEVEL IMPULSE OF INCREASED
VORTICITY AND OMEGA WILL SLIDE THROUGH THE LOWER MISSISSIPPI
VALLEY DURING THE AFTERNOON HOURS. THIS INCREASE IN LIFT ALOFT
SHOULD PROVIDE ENOUGH OF A CATALYST TO FIRE OFF ANOTHER ROUND OF
SHOWERS AND THUNDERSTORMS. HAVE LIKELY POPS IN PLACE FOR THE LATE
AFTERNOON AND EVENING HOURS TO REFLECT THIS RISK. OUTSIDE OF THE
POP ADJUSTMENTS...NO OTHER FORECAST CHANGES WERE MADE AT THIS
TIME. 32
PREV DISCUSSION... /ISSUED 758 AM CST WED DEC 23 2015/
.SOUNDING DISCUSSION...
BOTTOM LINE UP FRONT...ALL MODES OF SEVERE WEATHER REMAIN POSSIBLE
TODAY. A VERY MOIST ATMOSPHERE WAS SAMPLED THIS MORNING WITH A
PRECIPITABLE WATER VALUE OF 1.74 INCHES. THIS IS 2 STANDARD
DEVIATIONS ABOVE NORMAL AND A RECORD VALUE FOR THIS DATE/TIME.
MOST UNSTABLE CAPE OF ABOUT 1200 J/KG EXISTS WITH INHIBITION IN
THE FORM OF A CAPPING INVERSION. ASSUMING LOW CLOUDS AND FOG
DISSIPATE AND WE HAVE SOME SURFACE HEATING...THIS CAPPING
INVERSION SHOULD ERODE. WITH QUITE A BIT OF MOISTURE IN THE LOW-
LEVELS...THE DOWNDRAFT CAPE IS NOT IN THE OPTIMUM RANGE FOR
DAMAGING STRAIGHT LINE WINDS. THIS MAY CHANGE IF DRIER AIR MIXES
DOWN AND WINDS BECOME MORE UNIDIRECTIONAL. THE FREEZING LEVEL IS
NEAR 13000 FEET WHICH IS HIGH...BUT THERE WAS A REPORT EARLIER IN
THE NIGHT OF 1.25 INCH DIAMETER HAIL IN ASCENSION PARISH. 0-1KM
SRH AND 0-3KM SRH IS IMPRESSIVE AT 200 AND 340 M2/S2 RESPECTIVELY.
WINDS ARE FROM THE SOUTHEAST AT THE SURFACE AND THEN ARE
PREDOMINATELY FROM THE SOUTHWEST. SO THERE IS LOW LEVEL
DIRECTIONAL SHEAR CURRENTLY. THERE IS ALSO SOME SPEED SHEAR WITH
950MB AT 15 KNOTS...850MB AT 33 KNOTS...700MB AT 51 KNOTS...500MB
IS AT 58 KNOTS. A PEAK WIND SPEED OF 103 KNOTS WAS AT 39000 FEET
WITH A STORM TOP WIND SPEED NEAR 48000 FEET OF 72 KNOTS.
SPC HAS REQUESTED AN 18Z SOUNDING IN SUPPORT OF SEVERE WEATHER
OPERATIONS.
12Z BALLOON INFO: A SUCCESSFUL FLIGHT LASTING 85 MINUTES AND
REACHING A HEIGHT OF 14.8 MILES ABOVE THE GROUND. THE BALLOON
BURST OVER NEELY 84 MILES DOWNRANGE FROM THE OFFICE.
ANSORGE
PREV DISCUSSION... /ISSUED 406 AM CST WED DEC 23 2015/
SHORT TERM... ACTIVE CONDITIONS ONGOING ACROSS THE FORECAST AREA
THIS MORNING. LOCAL VAD WIND PROFILE SHOWS THAT LOW LEVEL WINDS HAVE
INCREASES SUBSTANTIALLY OVER THE LAST FEW HOURS WITH SE FLOW OF 30
KNOTS AT THE LOWEST OBS OF 1KFT AND VEERING TO SW WHILE INCREASING
TO 50KTS IN THE MID LEVELS. THIS IS THE PRIMARY REASON FOR THE
RECENT RAMP UP OF STRONG/SEVERE THUNDERSTORMS EARLY THIS MORNING.
HAVE RECEIVED 1 REPORT OF HAIL AND SEVERAL CELLS HAVE BROAD
ROTATION...INDICATIVE OF INCREASING SRH. THIS IS ALL HAPPENING
DESPITE BEING WITHIN A MARINE LAYER. THE TREND OF ACTIVE WEATHER
WITH THE POTENTIAL FOR A FEW CELLS PRODUCING HAIL OR A TORNADO WILL
CONTINUE THROUGH THE REST OF THE EARLY MORNING HOURS. THE BULK OF
STRONGER STORMS WILL SHIFT NORTHEAST AFTER SUNRISE AS SHORT WAVE
VORTMAX DOES SO AS WELL.
MOISTURE LEVELS REMAIN VERY HIGH ACROSS THE CENTRAL GULF COAST THIS
MORNING WITH THE 00Z SOUNDING FROM YESTERDAY AFTERNOON HAVING A
PRECIP WATER VALUE OF AROUND 1.7 INCHES WHICH IS RIGHT AT THE
CLIMATOLOGY MAX PER SPC SOUNDING INFO. BROAD LONG WAVE TROUGH IS
ALREADY IN PLACE OVER THE WESTERN HALF OF THE COUNTRY. AN EMBEDDED
WAVE WILL DIG AND SWING NEGATIVE OVER THE CENTRAL PLAINS TODAY. DOWN
AT THE SURFACE A LOW ON THE LEESIDE OF THE ROCKIES WILL BE RACING
NORTHEAST ACROSS THE CENTRAL MISSISSIPPI VALLEY. SURFACE PRESSURES
IN THE CWA WILL BE SLOWLY FALLING DURING THE DAY WITH A MINIMUM OF
APPROACHING 1000MB BY NOON BASED ON RUC OUTPUT. TIGHTENING OF THE
PRESSURE GRADIENT WILL INCREASE SURFACE WINDS INTO THE 15 TO 25
MPH RANGE. THIS SHOULD DO 2 THINGS...TRANSPORT OFFSHORE 70+DEGREE
DEWPOINTS FURTHER INLAND AS WELL AS INCREASE LOW LEVEL WIND SHEAR
SUBSTANTIALLY. HELICITY LIKELY TO FALL SOME AS WIND DIRECTION
BECOMES MORE CLOSELY ORIENTED TO THE MEAN FLOW OR MORE SOUTH TO
SOUTH WEST RATHER THAN CURRENT SOUTHEAST DIRECTION. PRESUMING THAT
SFC TEMPS DO REACH MID/UPPER 70S WHILE THESE DEWPOINTS
RISE...BUOYANCY AND INSTABILITY WILL SHOOT UP DURING THE DAY. BOTH
GFS AND NAM BUFR SOUNDINGS STILL SHOW SB AND PARCEL CAPE VALUES
WELL OVER 2000 J/KG AND MU CAPE UP TO 1500 J/KG ALL OVER THE CWA.
SPEED SHEAR LOOKING TO BE 40 TO 50 KNOTS IN THE BOUNDARY LAYER
WHICH IS PLENTY STRONG TO SUSTAIN SUPERCELLS. THUS THE POTENTIAL
FOR SEVERE WEATHER WILL DEFINITELY BE THERE TODAY. ALL MODES OF
SEVERE WEATHER ARE POSSIBLE. STILL OF CONCERN IS IF SFC TEMPS DONT
WARM ENOUGH... WILL JUST HAVE THE DYNAMICS. TOO STRONG OF A WARM
NOSE IN THE LOWER LEVELS COULD CAP THINGS AS WELL REGARDLESS...THE
POTENTIAL IS DEFINITELY THERE AND WARRANTS THE SLIGHT RISK AT THE
LEAST FOR THE ENTIRE CWA.
LONG TERM... RESIDUAL SURFACE BOUNDARY WILL BE THE FOCUS FOR
CONVECTION ON THURSDAY. AMPLE MOISTURE STILL LEFT IN THE AREA SHOULD
HAVE NO PROBLEM DEVELOPING INTO SHOWERS WITH POSSIBLY A FEW
THUNDERSTORMS. MUCH WEAKER WINDS IN THE COLUMN WILL LIMIT
ORGANIZATION OF STORMS BUT WONT BE SHORT OF INSTABILITY.
COVERAGE SHOULD STILL BE 50 TO 70 PERCENT FOR THE MOST PART.
CHRISTMAS DAY SHOULD BEGIN THE DOWNWARD TREND OF POPS AS UPPER LEVEL
RIDGE CENTERED OVER THE WESTERN ATLANTIC BUILDS BACK WESTWARD ACROSS
THE CWA. DESPITE THIS DECREASE IN COVERAGE...STILL PROBABLY LOOKING
AT 20 TO 30 PERCENT RAIN CHANCE. NO CHANCE IN THE TEMP FORECAST AND
EXPECTING NEAR RECORD MAX TEMPS AND RECORD HIGH LOWS. SADLY...THERE
IS A ZERO PERCENT CHANCE FOR A WHITE CHRISTMAS.
POPS TO FALL EVEN MORE DOWN INTO THE SLIGHT CHANCE CATEGORY THIS
WEEKEND AS THE RIDGE SHIFTS THE SHEAR ZONE FURTHER NORTH AND WEST.
GFS AND ECMWF BOTH CLOSE OFF A LOW IN THE DESERT SOUTHWEST AND
TRACKS EAST BEFORE SWINGING NE OVER THE CENTRAL PLAINS ENDING THE
WEEKEND. THIS WOULD BRING A LINE OF SHOWERS AND STORMS MOVING THRU
SOME TIME BETWEEN SUNDAY NIGHT AND MONDAY NIGHT DEPENDING ON MODEL
TIMING. NUDGED THE POPS TO THE SLOWER SOLUTION AS THE FASTER GFS IS
CLOSER TO AN OUTLIER SIDE OF THINGS.
MEFFER
AVIATION... SEVERE WEATHER CAME IN A LITTLE EARLIER TODAY THAN
EXPECTED. WILL KEEP THAT THREAT GOING THROUGH THE DAY BUT EXPECT A
REPRIEVE FOR SEVERAL HOURS AFTER DAYLIGHT TODAY. ANOTHER ROUND WILL
BE POSSIBLE THIS AFTERNOON BUT WILL HAVE TO SEE HOW THIS SHAPES UP.
CEILINGS WILL REMAIN FROM OVC020 TO OVC030 TODAY AND TONIGHT. RAIN
WILL ALSO CEASE FOR A WHILE TODAY AND WILL SHOW THIS IN THE 12Z TAF
PACKAGE.
WILL TAKE ANOTHER LOOK AT WX IN TAF SET LATER THIS MORNING.
MARINE... AS UPPER SYSTEM SWINGS THROUGH THE MIDDLE MISSISSIPPI
RIVER VALLEY TODAY...PRESSURE GRADIENT WILL TIGHTEN AND SMALL CRAFT
ADVISORIES AND EXERCISE CAUTION HEADLINES HAVE BEEN ISSUED AHEAD OF
THE SYSTEM. THIS SHOULD BE SOMEWHAT SHORT LIVED AS WINDS SUBSIDE
TONIGHT. NEXT PERIOD OF HEADLINES WILL BE EXERCISE CAUTION HEADLINES
OVER THE WEEKEND AS ONSHORE FLOW AGAIN STRENGTHENS.
DECISION SUPPORT...
DSS CODE....BLUE.
DEPLOYED...NONE.
ACTIVATION...NONE.
ACTIVITIES...MONITORING CONVECTIVE TRENDS.
DECISION SUPPORT SERVICES (DSS) CODE LEGEND
GREEN = NO WEATHER IMPACTS THAT REQUIRE ACTION
BLUE = LONG FUSED WATCH/WARNING/ADVISORY IN EFFECT OR HIGH
VISIBILITY EVENT
YELLOW = HEIGHTENED IMPACTS WITH SHORT FUSED WATCH/WARNING/ADVISORY
ISSUANCES; RADAR SUPPORT
ORANGE = HIGH IMPACTS - SLIGHT TO MODERATE RISK SEVERE; NEARBY
TROPICAL EVENTS; HAZMAT OR OTHER LARGE EPISODES
RED = FULL ENGAGEMENT FOR MODERATE RISK SVR AND/OR DIRECT
TROPICAL THREATS; EVENTS OF NATIONAL SIGNIFICANCE
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 64 77 68 77 / 70 60 40 30
BTR 65 79 70 79 / 70 50 30 40
ASD 67 76 68 77 / 70 70 30 30
MSY 69 76 69 77 / 70 70 30 30
GPT 68 74 68 74 / 70 70 30 20
PQL 69 74 68 75 / 70 70 30 20
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 6 PM CST THIS EVENING FOR GMZ530-532-
534-536-538-550-552-555-557-570-572-575-577.
MS...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 6 PM CST THIS EVENING FOR GMZ532-534-
536-538-550-552-555-557-570-572-575-577.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAY ME
330 PM EST WED DEC 23 2015
.SYNOPSIS...
LOW PRESSURE PASSES TO OUR WEST/NORTHWEST TONIGHT AND BRINGS
MODERATE TO HEAVY RAIN OUT AHEAD OF A WARM FRONT TONIGHT. THE
RAIN ENDS EARLY THURSDAY AND STRONG WARM AIR ADVECTION WILL SET
THE STAGE FOR SEVERAL RECORD HIGH TEMPERATURES TO BE
BROKEN...ESPECIALLY ACROSS SOUTHERN NEW HAMPSHIRE. A COLD FRONT
MOVES ACROSS THE AREA THURSDAY NIGHT AND ALTHOUGH TEMPERATURES
WILL RUN ABOUT 10 DEGREES COOLER ON CHRISTMAS DAY IT WILL STILL BE
QUITE PLEASANT WITH TEMPERATURES REMAINING WELL ABOVE NORMAL. OUR
NEXT STORM SYSTEM LOOKS TO ARRIVE LATE SATURDAY INTO SUNDAY AND
SHOULD BE MOSTLY IN THE FORM OF RAIN ONCE AGAIN. HOWEVER...COLDER
AIR WILL PUSH INTO THE REGION THE BEGINNING OF NEXT WEEK AND COULD
REMAIN IN PLACE LONG ENOUGH FOR SEVERAL LOCATIONS TO SEE THEIR
FIRST MEASURABLE SNOWFALL OF THE SEASON TUESDAY INTO WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
LOW LEVEL MOISTURE REMAINS TRAPPED BELOW A VERY SHARP AND SHALLOW
INVERSION EVIDENT ON THIS MORNINGS KGYX SOUNDING. SOME AREAS IN
NH HAVE MIXED OUT ON THE NORTHERN EDGE OF A STRATIFORM RAIN SHIELD
ALONG A NORTHWARD MOVING WARM FRONT. AS THE DEW POINT DEPRESSIONS
BECOME SMALLER HOWEVER FOG MAY AGAIN FORM IN AREAS IT HAS ALREADY
LIFTED.
THE DENSE FOG ADVISORY IN PLACE CONTINUES THROUGH 1 AM BUT
WILL LIKELY BE TRIMMED BACK AS THE RAIN ENTERS THE AREA AND
MECHANICALLY MIXES SOME OF THE MOISTURE OUT. HRRR AND OTHER
MESOSCALE MODELS INDICATE IN FACT THAT THE AREA OF DENSE FOG WILL
CONTINUE THROUGH AT LEAST MIDNIGHT BEFORE MOST OF IT DISSIPATES.
RAIN WILL BE HEAVY AT TIMES TONIGHT AND END MID MORNING
CHRISTMAS EVE. EXPECT DRIZZLE TONIGHT AND TOMORROW PRECEDING AND
BEHIND THE MAIN AREA OF PRECIPITATION. NOT EXPECTING THUNDERSTORMS
IN OUR AREA AS MID LEVEL INSTABILITY LOOKS TO STAY SOUTH. QPF
AMOUNTS WILL RANGE FROM A HALF INCH ACROSS THE NORTH TO ALMOST AN
INCH FROM THE FOOTHILLS SOUTH.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
MODELS ARE INDICATING A SIMILAR VERY SHARP INVERSION
TOMORROW AS TODAY...IE THE SAME LOW LEVEL LAYER OF MOISTURE WILL
ONLY MIX SO FAR EAST...DEPENDING ON WHERE THE WARM FRONT REACHES.
THERE IS LITTLE TO FORCE THE BOUNDARY UNTIL THE COLD FRONT
ARRIVES LATER CHRISTMAS EVE. THE NAM AND GEM ARE INDICATING A
VERY ABRUPT TEMPERATURE GRADIENT FROM WEST TO EAST ACROSS MAINE.
FOR THE MOST PART...NH WILL WARM INTO THE UPPER 50S TO EVEN UPPER
60S IN THE KEENE/MANCHESTER AREA AS THE WARM FRONT AT LEAST MAKES
IT THAT FAR. AS FOR MAINE...PORTIONS OF YORK COUNTY AND EVEN
CUMBERLAND COUNTY MIGHT REACH THE 60S...BUT FARTHER EAST WILL
LIKELY BE IN THE 50S AND EVEN UPPER 40S...AS SOME AREAS STRUGGLE
TO BREAK OUT OF FOG/STRATUS SIMILAR TO TODAY. ALL IN ALL IT WILL
BE A UNIQUE CHRISTMAS EVE FOR NEW ENGLAND...WITH RECORD-BREAKING
WARMTH LIKELY FROM NH SOUTHWEST.
RAIN...FOG...AND LOW LEVEL CLOUDS WILL BE SWEPT SOUTH AND EAST AS A
COLD FRONT MOVES THROUGH LATE CHRISTMAS EVE. SKIES SHOULD CLEAR OUT
FROM NORTH TO SOUTH EXCEPT FOR PERHAPS SOME CIRRUS.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
HIGHLIGHTS...
- ALTHOUGH COLD FRONT COMES THROUGH THURSDAY NIGHT...NEAR RECORD
TEMPERATURES WILL STILL BE POSSIBLE ON FRIDAY.
- FAST MOVING SYSTEM TO SPREAD MORE RAIN ACROSS MOST OF THE
REGION WITH POSSIBLE WINTRY MIX IN FAR NORTH.
- COOL HIGH PRESSURE WITH SEASONABLE TEMPS FOR THE BEGINNING OF
NEXT WEEK.
- POSSIBLE FIRST MEASURABLE SNOWFALL FOR MUCH OF THE AREA TUESDAY
INTO WEDNESDAY.
PATTERN SUMMARY: AS MENTIONED YESTERDAY...TELECONNECTION INDICES
WILL CONTINUE TO KEEP POLAR AIR CONFINED MOSTLY TO THE NORTH OF
THE REGION...WITH ONLY QUICK SHOTS OF SEASONABLE-LIKE WEATHER
FOLLOWED BY TEMPERATURES QUICKLY REBOUNDING TO ABOVE NORMAL
VALUES. THE HIGHLY AMPLIFIED RIDGE THAT IS OVER THE REGION TO
START THE PERIOD AND IS RESPONSIBLE FOR THE RECORD WARMTH FOR THE
NEXT TWO DAYS WILL FLATTEN OUT THIS WEEKEND. THIS WILL BRING US
BACK DOWN TO EARTH A BIT...WITH TEMPERATURES SATURDAY AND SUNDAY
LIKELY BEING ONLY SLIGHTLY ABOVE AVERAGE FOR THIS TIME OF YEAR. AS
WE HEAD INTO EARLY NEXT WEEK...THE NORTHERN STREAM WILL SINK
SOUTHWARD SLIGHTLY...ENOUGH TO BRING SOME SEASONABLE TEMPERATURES
AS COLD CANADIAN HIGH PRESSURE SINKS OVER THE REGION. HOW STRONG
THIS HIGH PRESSURE IS WILL DETERMINE IF THE COLD AIR WILL HOLD ON
LONG ENOUGH TO ALLOW FOR DECENT OVERRUNNING AND PROVIDE MOST OF US
WITH OUR FIRST MEASURABLE SNOWFALL OF THE SEASON. STILL QUITE A
LOT OF UNCERTAINTY THOUGH AT THIS POINT IN THE FORECAST...SO SNOW
LOVERS WILL JUST HAVE TO KEEP THEIR FINGERS CROSSED AND HOPE THE
FORECAST UNFOLDS TO THEIR LIKING.
DAY BY DAY...
CHRISTMAS DAY: HIGH FORECAST CONFIDENCE
WEATHER IMPACTS: LOW
MODEL GUIDANCE IS IN FAIRLY GOOD AGREEMENT FOR CHRISTMAS. COLD
FRONT PUSHES THROUGH THE AREA THURSDAY NIGHT INTO FRIDAY MORNING.
ALTHOUGH IT IS A COLD FRONT...THIS MAY ACTUALLY HELP SOME AREAS
WARM UP AS WARM AIR ALOFT MIXES DOWN TO THE SURFACE. TEMPERATURES
ARE LIKELY TO CLIMB TO NEAR RECORD VALUES ON FRIDAY AND DEPENDING
ON HOW FAR NORTH THE SURFACE WARM FRONT MAKES IT ON THURSDAY...MANY
PLACES MAY ACTUALLY TURN OUT WARMER ON CHRISTMAS DAY AS WE TAP
INTO THAT WARMER AIR ALOFT.
SATURDAY AND SUNDAY: MODERATE TO HIGH FORECAST CONFIDENCE
WEATHER IMPACTS: LOW
SHORT WAVE ARRIVES FROM THE SOUTHWEST SATURDAY NIGHT AND HIGH
PRESSURE OVERHEAD SHIFTS OFFSHORE. 12Z MODEL GUIDANCE HAS TRENDED
A BIT WARMER WITH TEMPERATURES ALOFT AND AT THE SURFACE WITH THIS
SYSTEM. FOR NOW IT APPEARS THAT THE BULK OF THE AREA WILL JUST SEE
LIQUID PRECIPITATION...BUT NORTHERN ZONES LOOK TO POTENTIALLY BE
BELOW FREEZING IN THE FOOTHILLS AND MOUNTAIN VALLEYS. THIS COULD
CAUSE A PERIOD OF POSSIBLE MIXED PRECIP OR FREEZING RAIN IN SOME
LOCATIONS. UPPER LEVEL FLOW WILL BE NEARLY ZONAL OVER THE
NORTHEAST CONUS BY THAT TIME...SO THIS SYSTEM SHOULD MOVE THROUGH
RATHER QUICKLY MAKING QPF LIMITED.
MONDAY - WEDNESDAY: LOW TO MODERATE FORECAST CONFIDENCE
WEATHER IMPACTS: POSSIBLY MODERATE WITH WINTRY PRECIPITATION
COLD CANADIAN HIGH PRESSURE DROPS DOWN OVER THE REGION AND
SHOULD MAKE FOR SEASONABLE HIGH TEMPERATURES. STRENGTH AND TIMING
OF THIS HIGH WILL DETERMINE HOW THE FORECAST UNFOLDS THEREAFTER.
EURO HAS STRONG HIGH PRESSURE MOVING RIGHT OVER NEW ENGLAND WHILE
THE GFS HAS A WEAKER SURFACE HIGH AND KEEPS THE HIGH IN CANADA
WITH SURFACE RIDGE EXTENDING OUT OVER NEW ENGLAND. THE EURO
SOLUTION WOULD KEEP COLD AIR IN PLACE MUCH LONGER AND DELAY THE
ONSET OF PRECIPITATION AS LOW PRESSURE APPROACHES FROM THE
SOUTHWEST. WARM AIR ADVECTION/OVERRUNNING ALOFT WILL BRING THE
POTENTIAL FOR PRECIPITATION TO START OFF AT LEAST AS ALL SNOW FOR
THE ENTIRE AREA. HOWEVER...WITH THE CURRENT TRACK OF THIS SYSTEM
FORECAST TO BE WEST OF THE REGION...AN EVENTUAL TRANSITION TO RAIN
WOULD LIKELY OCCUR ...BUT WILL CERTAINLY HAVE TO WATCH THE MODEL
TRENDS IN THE COMING DAYS AS THE 12Z EURO HAS NOW TRENDED EVEN
COLDER THAN THE 00Z RUN.
&&
.AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
SHORT TERM...AREAS OF DENSE FOG WILL MAKE FOR LIFR CONDITIONS
FOR MUCH OF THE NIGHT. RAIN WILL SPREAD FROM THE SW AND IMPROVE
VISIBILITIES FOR A TIME. RAIN MAY BE HEAVY AT TIMES HOWEVER...AND
DRIZZLE IS LIKELY ALONG THE COAST AHEAD OF AND BEHIND THE MAIN
PRECIPITATION SHIELD. FOG WILL AGAIN BE AN ISSUE THURSDAY MORNING.
LONG TERM...VFR CONDITIONS EXPECTED UNTIL SATURDAY NIGHT INTO
SUNDAY...AS OUR NEXT SYSTEM COMES THROUGH THE AREA AND IFR OR
LOWER CONDITIONS ARE POSSIBLE THRU THE DAY ON SUNDAY. CANNOT RULE
OUT SOME MIXED PRECIP EITHER...ESPECIALLY FOR NORTHERN TERMINALS.
AT THIS TIME FORECAST CONFIDENCE IS LOW REGARDING SPECIFIC PRECIP
TYPES. HIGH PRESSURE AND VFR CONDITIONS WILL BUILD BACK INTO THE
REGION FOR MONDAY.
&&
.MARINE...
SHORT TERM...SMALL CRAFT ADVISORY IS IN EFFECT BEGINNING TONIGHT
THROUGH TOMORROW FOR THE BAYS AND OUTER WATERS.
LONG TERM...HIGH PRESSURE AND OUR NEXT ARRIVAL OF COLD AIR WILL
BE MONDAY AND THIS MAY BRING A PERIOD OF SCA CONDITIONS WITH IT.
THIS WILL BE FOLLOWED BY A LOW PRESSURE LIKELY PASSING WEST OF
THE WATERS...WITH SOUTHWESTERLY WINDS WITH SCA CONDITIONS AHEAD
OF IT.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...DENSE FOG ADVISORY UNTIL 1 AM EST THURSDAY FOR MEZ007>009-
012>014-018>028.
NH...DENSE FOG ADVISORY UNTIL 1 AM EST THURSDAY FOR NHZ010-014.
MARINE...SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 1 PM EST
THURSDAY FOR ANZ151-153.
SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 6 PM EST
THURSDAY FOR ANZ150-152-154.
&&
$$
SYNOPSIS...KISTNER
NEAR TERM...HANES
SHORT TERM...HANES
LONG TERM...KISTNER
AVIATION...HANES/KISTNER
MARINE...HANES/KISTNER
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
442 PM EST WED DEC 23 2015
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 440 PM EST WED DEC 23 2015
WV IMAGERY AND RAP ANALYSIS INDICATED A BROAD TROUGH OVER THE WRN
CONUS AND A RIDGE FROM THE WRN ATLANTIC INTO NEW ENGLAND RESULTING
IN SSW FLOW FROM THE SRN PLAINS INTO THE WRN GREAT LAKES. A VIGOROUS
SHORTWAVE TROUGH OVER CNTRL IA WAS LIFTING QUICKLY TO THE NORTHEAST.
AT THE SFC...A 983 MB LOW WAS LOCATED OVER ERN IA WITH A WARM FRONT
TO THE EAST THROUGH SRN LAKE MI. AN AREA OF RAIN OVER UPPER MI AND
NE WI SUPPORTED BY 295K-300K ISENTROPIC LIFT AHEAD OF THE SHRTWV AND
WARM FRONT WAS LIFTING TO THE NNE. TO THE WEST...SNOW OVER NE MN
INTO NW WI WAS ASSOCIATED WITH A BAND OF 850-700 MB
FGEN/DEFORMATION.
TONIGHT...AFTER THE FIRST BATCH OF PCPN MOVES OUT OF THE CNTRL AND
EAST...THE AREA OF FGEN AND 700-300 MB QVECTOR CONV AHEAD OF THE
SHRTWV WILL BRING MORE PCPN THROUGH UPPER MICHIGAN. AS THE TROUGH
AND COLD FRONT NEAR IWD AND 00Z MOVES TO THE NEAR MQT-IMT BY 06Z AND
ERY AROUND 09Z THE RAIN WILL CHANGE TO SNOW. HOWEVER...THE HEAVIEST
PCPN...AS RAIN...IS EXPECTED BEFORE THE COLD AIR MOVES IN. THE
EXCEPTION WILL BE OVER THE FAR WEST (NEAR IWD) WHERE 1 TO 4 INCHES
WILL BE POSSIBLE AND A WINTER WX WAS ISSUED. OTHERWISE...ANY
ACUMULATIONS WILL AMOUNT TO AN INCH OR LESS.
THE OTHER MAIN CONCERN IS THE POTENTIAL FOR STRONG WINDS OVERNIGHT.
AS THE FRONT LIFTS THROUGH A VERY STRNOG ISALLOBARIC COMPONENT WITH
12 MB/3HR PRES RISE WILL BRING VERY GUSTY WINDS TO ESPECIALLY THE
ERN CWA BTWN 06Z-12 WHERE A WIND ADVY IS IN EFFECT. WRLY WINDS WILL
ALSO BE VERY GUSTY OVER THE KEWEENAW WHERE 925 MB WINDS TO 50 KT ARE
FCST.
THURSDAY...A THE STORNG PRES GRADIENT WILL CONTINUE TO BRING GUSTY
WINDS TO UPPER MICHIGAN DURING THE MORNING. THE ADVY WAS MAINTAINED
TIL 21Z OVER THE KEWEENAW GIVEN THE FAVORABLE EXPOSURE TO THE STRONG
WEST WINDS THROUGH MID AFTERNOON. 850 MB TEMPS TO AROUND -8C WILL
ALSO SUPPORT ADDITIONAL LAKE ENHANCED SNOW INTO THE KEWEENAW AS THE
DEEPER WRAP-AROUND MOISTURE LINGERS.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 342 PM EST WED DEC 23 2015
SURFACE LOW WILL CONTINUE TO LIFT PRETTY QUICKLY NORTHEASTWARD INTO
QUEBEC THURSDAY EVENING WITH SURFACE RIDGING BUILDING ACROSS THE
GREAT LAKES FOR CHRISTMAS EVE NIGHT AND THROUGH THE DAY ON
CHRISTMAS. WINDS WILL DIMINISH THURSDAY EVENING WITH A PRETTY
TRANQUIL CHRISTMAS DAY EXPECTED ACROSS THE UP. WITH SOME SUNSHINE
TEMPERATURES WILL CLIMB INTO THE LOWER AND MIDDLE 30S...ABOUT 5 TO
10 DEGREES ABOVE AVERAGE.
ATTENTION WILL THEN TURN TO NORTHERN STREAM UPPER TROUGHING MOVING
EASTWARD ALONG THE CANADIAN BORDER TOWARDS THE UPPER GREAT LAKES
ALONG WITH SHORT WAVE ENERGY LIFTING NORTHEASTWARD FROM THE
DEVELOPING CLOSED LOW OVER THE FOUR CORNERS REGION. MODELS CONTINUE
SHOW A SIGNIFICANT AMOUNT OF UNCERTAINTY STILL WITH THE
PRECIPITATION. GFS AND ECMWF SEEM TO BE MOST CONSISTENT WITH SHOWING
BEST WARM ADVECTION AND FRONTOGENESIS ACROSS THE AREA ON SATURDAY
YIELDING A MARGINAL ADVISORY SNOWFALL FOR THE CENTRAL AND WESTERN UP
WITH SNOW AMOUNTS IN THE 2-4 INCH RANGE WITH LOCALLY HIGHER AMOUNTS
IN THE UPSLOPE AREAS FAVORED BY NORTHEAST WINDS. NAM AND GEM TO A
LESSER EXTENT STILL MORE SHEARED OUT AND KEEP STRONGEST FORCING
SOUTH AND EAST OF THE AREA.
HIGH PRESSURE WITH SEASONABLE TEMPERATURES WILL BUILD BACK ACROSS
THE AREA FOR THE SUNDAY INTO MONDAY TIME PERIOD. 85H TEMPERATURES
WILL BE MARGINAL FOR LIGHT NORTH TO NORTHWEST WIND LAKE EFFECT
SATURDAY NIGHT INTO SUNDAY BUT ANY ACCUMULATIONS WILL BE LIGHT.
MAIN UPPER LOW WILL BEGIN TO EJECT OUT OF THE SOUTHWEST EARLY NEXT
WEEK WITH VARYING SOLUTIONS ON THE TRACK OF THE SURFACE LOW. ECMWF
MOST WOUND UP WITH A TRACK MORE FAVORABLE FOR ACCUMULATING SNOW FOR
MUCH OF THE AREA. GFS IS FARTHER SOUTH AND EAST SUGGESTING ANY
SIGNIFICANT PRECIPITATION STAYS SOUTH AND EAST OF THE AREA. DETAILS
WILL BE RESOLVED OVER THE COMING DAYS WITH A MODEL BLEND THE BEST
COURSE OF ACTION AT THIS TIME.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 100 PM EST WED DEC 23 2015
VLIFR CIGS ARE EXPECTED TODAY INTO THIS EVENING AS VERY
MOIST LOW LEVEL AIR REMAINS OVER THE REGION WITH SRLY FLOW AND LIGHT
PCPN. VSBY AT OR BELOW MINS ARE EXPECTED TO CLIMB WHEN HEAVIER RAIN
DEVELOPS ESPECIALLY LATE THIS AFTERNOON AND EVENING. LLWS IS
EXPECTED AT SAW TONIGHT WITH A STRONG SW LOW LEVEL JET ABOVE THE
MAINLY DECOUPLED SFC WINDS. RAIN WILL CHANGE OVER TO SNOW FROM WEST
TO EAST LATE THIS EVENING AND OVERNIGHT. GUSTY WEST WINDS WILL
DEVELOP LATE TONIGHT AT IWD/CMX AND THU MORNING AT SAW AS THE
STRONG LOW LIFTS TO THE NORTH OF THE REGION.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 440 PM EST WED DEC 23 2015
SIGNIFICANT WIND EVENT WILL OCCUR TONIGHT INTO THURSDAY ACROSS THE
WATERS AND THE WIND WILL INCREASE RAPIDLY LATE TONIGHT. A TIGHT
PRESSURE GRADIENT LATE TONIGHT COMBINED WITH A STRONG PRESSURE RISE
OF 12 MB IN THREE HOURS OVER LAKE MICHIGAN WILL CAUSE STORM FORCE
WINDS ACROSS EASTERN LAKE SUPERIOR AND NORTHERN LAKE MICHIGAN LATE
TONIGHT INTO THURSDAY AND A HIGH END GALE ACROSS THE WEST HALF OF
LAKE SUPERIOR. ONCE THIS EVENT ENDS THURSDAY AFTERNOON...WINDS LOOK
TO STAY BELOW 30 KNOTS THROUGH THE REST OF THE PERIOD.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WIND ADVISORY FROM 3 AM EST /2 AM CST/ TO 1 PM EST /NOON CST/
THURSDAY FOR MIZ007-012>014-085.
WIND ADVISORY FROM 5 AM TO 4 PM EST THURSDAY FOR MIZ001-003.
WINTER WEATHER ADVISORY UNTIL 4 AM CST THURSDAY FOR MIZ009.
LAKE SUPERIOR...
STORM WARNING FROM 5 AM TO 7 PM EST THURSDAY FOR LSZ265>267.
GALE WARNING FROM 3 AM EST /2 AM CST/ TO 7 PM EST /6 PM CST/
THURSDAY FOR LSZ162-240>245-263-264.
GALE WARNING FROM 5 AM TO 7 PM EST THURSDAY FOR LSZ246>251.
LAKE MICHIGAN...
STORM WARNING FROM 1 AM TO NOON EST THURSDAY FOR LMZ221-248-250.
GALE WARNING FROM NOON TO 5 PM EST THURSDAY FOR LMZ221-248-250.
&&
$$
SHORT TERM...JLB
LONG TERM...MZ
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1254 PM EST WED DEC 23 2015
.AVIATION...
WARM FRONT CURRENTLY LIFTING NORTH THROUGH LOWER MICHIGAN RESULTING
IN CONTINUED LIFR/IFR CONDITIONS INTO THE AFTERNOON HOURS. ELEVATED
FRONT SEEN ON RADAR PRODUCING SHOWERS BUT ACTUAL SURFACE FRONT
REMAINS QUITE DIFFUSE. SHOULD SEE SOME IMPROVEMENTS LATER THIS
AFTERNOON AS WE GET DEEPER INTO THE WARM SECTOR WITH CIGS LIFTING TO
MVFR. THIS WILL LAST A FEW HOURS BEFORE PRE FRONTAL SHOWERS AND
THUNDERSTORMS TRACK EAST THROUGH THE AREA. THE COLD FRONT WILL
FOLLOW AROUND 09Z SWITCHING WINDS FROM SOUTHERLY TO SOUTHWEST. WIND
SPEEDS WILL INCREASE DRAMATICALLY WITH GUSTS POSSIBLY EXCEEDING 35
KNOTS FOR ALL TAF SITES...AND POSSIBLY OVER 45 KNOTS FOR MBS AND
FNT. ON THURSDAY WINDS WILL GRADUALLY DECREASE WHILE DRIER AIR ALOFT
PRODUCES CLEARING SKIES.
FOR DTW...IFR/LIFR WILL LINGER A FEW MORE HOURS BEFORE FINALLY
LIFTING TO MVFR AS WE GET DEEPER INTO THE WARM SECTOR. MAY BE A
COUPLE BRIEF PERIODS OF DRIZZLE BUT SHOULD NOT PERSIST LONG AT ALL.
SHOWERS AND POSSIBLY THUNDERSTORMS WILL APPROACH THE TERMINAL AROUND
00-03Z THIS EVENING AHEAD OF A COLD FRONT. MAIN THREAT WILL BE
STRONG WINDS ALOFT MIXING DOWN TO THE SURFACE. LONGER DURATION WIND
EVENT WILL OCCUR AFTER THE COLD FRONTAL PASSAGE AROUND 09Z WHERE
GUSTS WILL REACH 30 TO 35 KNOTS.
//DTW THRESHOLD PROBABILITIES...
* HIGH FOR CEILING BELOW 5000 FEET THROUGH TONIGHT.
* LOW FOR CIGS/VSBY BELOW 200FT AND/OR 1/2SM THIS AFTERNOON.
* MEDIUM THAT THUNDERSTORMS WILL IMPACT THE TERMINAL BETWEEN 00-03Z.
* MODERATE TO HIGH FOR GUSTS EXCEEDING CROSSWIND THRESHOLD AFTER 09Z.
&&
.PREV DISCUSSION...ISSUED 1147 AM EST WED DEC 23 2015
UPDATE...
FORECAST RATIONAL REMAINS LARGELY UNCHANGED AFTER WATCHING RADAR
AND SATELLITE TRENDS THIS MORNING AND PERUSING INITIAL 12Z MODEL
GUIDANCE. LEAD BATCH OF SHOWERS WITH A FEW RUMBLES OF THUNDER WILL
CONTINUE TO LIFT NORTH THROUGH THE FORECAST AREA ON NOSE OF WARM
FRONTAL BOUNDARY. THIS FRONT WILL GRADUALLY BECOME BETTER DEFINED
AS IT CROSSES NORTH THROUGH THE AREA THIS AFTERNOON. TEMPERATURES
WILL CLIMB THROUGH THE 50S DURING THAT TIME FRAME...AND REACH 60
DEGREE IN SOME LOCATIONS BY LATE AFTERNOON.
WHILE SCATTERED SHOWERS AND A FEW THUNDERSTORMS WILL BECOME
INCREASINGLY WIDESPREAD DURING THE COURSE OF THE AFTERNOON...THE
MAIN FOCUS WILL BE A LARGE AREA OF VIGOROUS CONVECTION CURRENTLY
EXTENDING FROM PARTS OF ILLINOIS SOUTH INTO SOUTHEAST MISSOURI
AND ARKANSAS WHERE THE THUNDERSTORM ACTIVITY IS PARTICULARLY
STRONG IN ADVANCE OF PRE-FRONTAL TROUGH PIVOTING EAST NORTHEAST
AROUND DEEPENING LOW PRESSURE OVER EASTERN KANSAS. 12Z MODEL
RUNS...SUPPORTED BY HI RES HRRR AND RAP RUNS THIS MORNING SUGGEST
SOME SEMBLANCE OF THESE LINE OF STORMS WILL ARC INTO SOUTHEAST
LOWER MICHIGAN BETWEEN 5 AND 8 PM...BRINGING THE POTENTIAL OF
DAMAGING WINDS...AND PERHAPS AN ISOLATED TORNADO GIVEN THE STRONG
BULK WIND SHEAR PRESENT IN THE LOWEST PART OF THE ATMOSPHERE.
INSTABILITY...OR LACK THEREOF...REMAIN THE MAIN NEGATING FACTOR
AS CAPE VALUE ARE FORECAST TO REMAIN BELOW 500 J/KG AS THIS LEAD
ACTIVITY MOVES INTO THE AREA WITH HIGHER VALUES THEN CREEPING
NORTH DURING THE REST OF THE EVENING IN ADVANCE OF COLD FRONT TO
AT LEAST MAINTAIN THE CHANCE OF STORMS. VERY STRONG WINDS ARE
STILL EXPECTED ALONG/BEHIND THE COLD FRONT OVERNIGHT AND A WIND
ADVISORY WILL MOST LIKELY BE REQUIRED FOR THE AREA...AT LEAST FOR
A SHORT TIME OVERNIGHT INTO PARTS OF THURSDAY MORNING. FINAL
DECISIONS ON THIS WILL BE IRONED OUT THIS AFTERNOON.
PREV DISCUSSION...ISSUED 337 AM EST WED DEC 23 2015
DISCUSSION...
LATEST WATER VAPOR IMAGERY SHOWS DEEPENING LONGWAVE TROUGH OVER
CENTRAL NORTH AMERICA...WITH THE FLOW OVER THE GULF COAST STATES
BACKING TO THE SOUTH. HOWEVER...THE LEAD MOISTURE ORIGINATING FROM
TENNESSEE/KENTUCKY IS EXPECTED TO SLIDE NORTHEAST INTO THE EASTERN
GREAT LAKES...PER 850 MB THETA-E FIELDS...WITH THE CORRESPONDING
NEGATIVE LI`S MOSTLY EAST...AND HAVE BACKED OFF ON THUNDERSTORM AND
POP MENTION THIS MORNING. STILL ENOUGH LOW LEVEL MOISTURE
ADVECTION/ISENTROPIC ASCENT AND EVENTUAL SATURATION TO TRIGGER
LIGHT RAIN/DRIZZLE AS THE DAY WEARS ON.
OUR FOCUS THIS EVENING/TONIGHT IS ON THE MOISTURE OVER EASTERN TEXAS
WHICH WILL BE ACCELERATING OFF TO THE NORTHEAST...AS EXPLOSIVE
CYCLOGENESIS (20 MB IN 24 HRS) EXPECTED TO TAKE PLACE.
DEEPENING SURFACE LOW TRACKS THROUGH THE WESTERN GREAT LAKES THIS
EVENING...AND NORTHEAST INTO JAMES BAY THURSDAY MORNING...AS
PHASING/CONSOLIDATION OF UPPER LEVEL PV (DAKOTAS/SOUTHERN PLAINS)
TAKES PLACE...DIRECTED AND SPED UP BY THE VERY STRONG UPPER LEVEL
WAVE/PV SLICING THROUGH THE PACIFIC NORTHWEST...HELPING TO FUEL
THE AGGRESSIVE DEVELOPMENT.
THE MOISTURE/CONVECTIVE AXIS LOOKS TO BE MOVING THROUGH SOUTHEAST
MICHIGAN AROUND MIDNIGHT...AND THE 00Z NAM IS INDICATING
CONSIDERABLE MORE INSTABILITY AS SURFACE BASED CAPES REACH TO AROUND
750 J/KG...WHILE THE GFS REMAINS MORE SUBDUED...STRUGGLING TO REACH
300 J/KG. INTERESTING...THE SURFACE DEW PT FORECAST FOR BOTH MODELS
ARE VERY CLOSE...SNEAKING INTO THE UPPER 50S. EVEN TAKING A BLEND OF
THE TWO SOLUTIONS..THE EXCEPTIONAL WIND FIELDS (50-55 KNOTS AT 925
MB/60+ KNOTS AT 850 MB) SUPPORT A DAMAGING WIND THREAT WITH ANY
VIGOROUS CONVECTION...WITH SEEMS LIKE A DECENT
POSSIBILITY/SCATTERED THUNDERSTORM COVERAGE...AS MID LEVEL LAPSE
(700-500 MB) LOOK TO BE AROUND 7 C/KM TO POSSIBLY AS HIGH AS 8
C/KM (SEE 00Z EURO). PLANNING ON INCLUDING DAMAGING WIND POTENTIAL
IN THE ZONES...AS LATEST SPC DAY 1 HAS TRENDED SOUTHEAST MICHIGAN
INTO THE MARGINAL TO SLIGHT CHANCE CATEGORIES NOW. STILL CAN`T
RULE OUT ISOLATED TORNADOES WITH EXTREME 0-1 KM BULK SHEAR (UP
NEAR 50 KNOTS) AND MUCH OF THE CAPE DENSITY DOWN LOW. VARIOUS
HIRES MODELS ARE GIVING MIXED SIGNALS...AND ARE INDICATING FASTER
ARRIVAL TIME OF CONVECTION DURING THE EARLY EVENING HOURS...WITH
OTHERS INDICATING MORE OF A MUTED RESPONSE THROUGH THE ENTIRE
NIGHT.
925 MB TEMPS INCREASING BETWEEN 13 TO 14 C TOWARD MIDNIGHT STILL
SUGGESTING LOWER 60S WILL BE NO PROBLEM...AND LOOKS LIKE WE WILL
DOUBLE DIP AND SET TWO DAYS OF RECORD HIGHS.
HIGH TEMPERATURE RECORDS FOR DECEMBER 23RD:
DTW 56 (1893)
FNT 55 (1982)
MBS 53 (1982)
DECEMBER 24TH
DTW 61 (1889)
FNT 56 (1982)
MBS 55 (1932)
PW VALUES AROUND 1.25 INCHES...850 MB DEW PTS 10+ C...CONTINUE TO
SUGGEST POTENTIAL RAINFALL AROUND HALF INCH...WITH
LOCALIZED/ISOLATED 1+ INCH TOTALS NOT OUT OF THE QUESTION.
THE ACTUAL COLD FRONTAL PASSAGE LOOKS TO BE TOWARD 12Z
THURSDAY...AND GOOD CHANCE LOCATIONS NORTH OF I-69 WILL SEE GUSTS OF
45+ MPH WITH SUBSIDENCE/COLD ADVECTION POP...AS 850 MB TEMPS CRASH
TO NEAR ZERO. ELECTED TO NOT ISSUE WIND ADVISORY AT THIS TIME...AS
FOCUS IS MORE ON SEVERE/DAMAGING WIND POTENTIAL...AND WE ARE TALKING
VERY LATE SECOND PERIOD.
UPPER LEVEL WEST-SOUTHWEST CONFLUENT FLOW THURSDAY-FRIDAY LOOKS TO
KEEP SOUTHEAST MICHIGAN MAINLY DRY...WITH TEMPERATURES STILL SOLIDLY
ABOVE NORMAL AND ABOVE FREEZING THE MAJORITY OF THE TIME.
PER 00Z EURO... IT LOOKS LIKE THE WEEKEND WILL FEATURE SPLIT UPPER
LEVEL FLOW..WITH CUTOFF UPPER LEVEL LOW OVER THE FOUR CORNERS
REGION...AND PROGRESSIVE NORTHERN STREAM SHORTWAVE TROUGH SLIDING
THROUGH THE GREAT LAKES ON SUNDAY. A WAVE OF LOW PRESSURE LOOKS TO
BE SCOOTING OFF TO THE NORTHEAST OUT OF THE SOUTHERN PLAINS/MIDWEST
ON SATURDAY...WITH THERMAL PROFILES SUGGESTING ALL RAIN FOR
SOUTHEAST MICHIGAN.
MARINE...
SURFACE LOW PRESSURE WILL RAPIDLY DEEPEN THIS EVENING TO 980 MB
WHILE TRACKING NORTHWARD ACROSS WISCONSIN AND LAKE SUPERIOR. A TIGHT
PRESSURE GRADIENT IS FORECASTED TO DEVELOP ALONG THE SOUTHEASTERN
FLANK OF THE LOW PRESSURE CENTER OVER LAKE MICHIGAN AND PORTIONS OF
NORTHERN LOWER MICHIGAN SIGNALING A HIGH POTENTIAL FOR STRONG WINDS.
TIMING OF THE STRONG COLD FRONT THROUGH THE STATE IS AFTER 09Z.
SOUTHEASTERLY WINDS WILL APPROACH GALE FORCE TODAY OVER THE OPEN
WATERS OF LAKE HURON. THE MOST IMPACTFUL PART OF THE LOW PRESSURE
SYSTEM WILL BE THE WESTERLY WINDS FORECASTED TO DEVELOP IN THE WAKE
OF THE COLD FRONT LATE TONIGHT AND THURSDAY. WHILE WESTERLY WINDS
ARE EXPECTED TO BE STRONG OVER ALL OF LAKE HURON...THE NORTH HALF OF
LAKE HURON WILL BE IN THE BETTER POSITION TO WITNESS WIND GUSTS TO
45 KNOT GALES. GALE WARNINGS HAVE BEEN ISSUED FOR ALL OF LAKE HURON.
RAPID MOVEMENT OF THE SURFACE LOW TO JAMES BAY...WITH A FAST
EVOLVING UPPER LEVEL PATTERN...SUPPORTS A RELATIVELY QUICK
DIMINISHING WIND TREND ALREADY THURSDAY AFTERNOON AND EVENING. WIND
GUSTS ARE EXPECTED TO DROP BELOW 20 KNOTS BY 06Z FRIDAY.
HYDROLOGY...
A LOW PRESSURE SYSTEM WILL STRENGTHEN TODAY WHILE TRACKING NORTHEAST
TO LAKE SUPERIOR. THE LOW PRESSURE SYSTEM WILL LIFT A STRONG WARM
FRONT THROUGH SOUTHERN MICHIGAN...BRINGING VERY WARM AND MOIST AIR
TO THE REGION. THERE WILL BE MULTIPLE OPPORTUNITIES FOR RAINFALL
TODAY...WITH THE POTENTIAL FOR BRIEF HEAVY RAINFALL IN POTENTIAL
THUNDERSTORM DEVELOPMENT WAITING UNTIL THE LATE AFTERNOON OR DURING
THE LATE EVENING HOURS. MOST LOCATIONS WILL SEE AROUND 0.5 INCHES OF
RAIN BY THURSDAY MORNING WITH ISOLATED TOTALS OF AROUND 1.0 INCH.
LITTLE CONCERN FOR FLOODING EXISTS.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...GALE WARNING FROM 3 AM TO NOON EST THURSDAY FOR LHZ421-422-441-462.
GALE WARNING FROM 4 AM TO 10 AM EST THURSDAY FOR LHZ442-443-463-464.
GALE WARNING FROM 7 PM THIS EVENING TO 3 PM EST THURSDAY FOR
LHZ361>363.
LAKE ST CLAIR...SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST THURSDAY
FOR LCZ460.
MICHIGAN WATERS OF LAKE ERIE...SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST THURSDAY
FOR LEZ444.
&&
$$
AVIATION.....DRK
UPDATE.......DG
DISCUSSION...SF
MARINE.......CB
HYDROLOGY....CB
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1147 AM EST WED DEC 23 2015
.UPDATE...
FORECAST RATIONAL REMAINS LARGELY UNCHANGED AFTER WATCHING RADAR
AND SATELLITE TRENDS THIS MORNING AND PERUSING INITIAL 12Z MODEL
GUIDANCE. LEAD BATCH OF SHOWERS WITH A FEW RUMBLES OF THUNDER WILL
CONTINUE TO LIFT NORTH THROUGH THE FORECAST AREA ON NOSE OF WARM
FRONTAL BOUNDARY. THIS FRONT WILL GRADUALLY BECOME BETTER DEFINED
AS IT CROSSES NORTH THROUGH THE AREA THIS AFTERNOON. TEMPERATURES
WILL CLIMB THROUGH THE 50S DURING THAT TIME FRAME...AND REACH 60
DEGREE IN SOME LOCATIONS BY LATE AFTERNOON.
WHILE SCATTERED SHOWERS AND A FEW THUNDERSTORMS WILL BECOME
INCREASINGLY WIDESPREAD DURING THE COURSE OF THE AFTERNOON...THE
MAIN FOCUS WILL BE A LARGE AREA OF VIGOROUS CONVECTION CURRENTLY
EXTENDING FROM PARTS OF ILLINOIS SOUTH INTO SOUTHEAST MISSOURI
AND ARKANSAS WHERE THE THUNDERSTORM ACTIVITY IS PARTICULARLY
STRONG IN ADVANCE OF PRE-FRONTAL TROUGH PIVOTING EAST NORTHEAST
AROUND DEEPENING LOW PRESSURE OVER EASTERN KANSAS. 12Z MODEL
RUNS...SUPPORTED BY HI RES HRRR AND RAP RUNS THIS MORNING SUGGEST
SOME SEMBLANCE OF THESE LINE OF STORMS WILL ARC INTO SOUTHEAST
LOWER MICHIGAN BETWEEN 5 AND 8 PM...BRINGING THE POTENTIAL OF
DAMAGING WINDS...AND PERHAPS AN ISOLATED TORNADO GIVEN THE STRONG
BULK WIND SHEAR PRESENT IN THE LOWEST PART OF THE ATMOSPHERE.
INSTABILITY...OR LACK THEREOF...REMAIN THE MAIN NEGATING FACTOR
AS CAPE VALUE ARE FORECAST TO REMAIN BELOW 500 J/KG AS THIS LEAD
ACTIVITY MOVES INTO THE AREA WITH HIGHER VALUES THEN CREEPING
NORTH DURING THE REST OF THE EVENING IN ADVANCE OF COLD FRONT TO
AT LEAST MAINTAIN THE CHANCE OF STORMS. VERY STRONG WINDS ARE
STILL EXPECTED ALONG/BEHIND THE COLD FRONT OVERNIGHT AND A WIND
ADVISORY WILL MOST LIKELY BE REQUIRED FOR THE AREA...AT LEAST FOR
A SHORT TIME OVERNIGHT INTO PARTS OF THURSDAY MORNING. FINAL
DECISIONS ON THIS WILL BE IRONED OUT THIS AFTERNOON.
&&
.AVIATION...ISSUED 652 AM EST WED DEC 23 2015
AGGRESSIVE IFR/LIFR CIG/VSBY TREND DEVELOPING OVER LOWER MICHIGAN
THIS MORNING AS IMPRESSIVE LOW LEVEL THETA E SURGE IS NOW UNDERWAY.
THE FIRST POTENTIAL FOR SHOWER ACTIVITY...LIKELY A BRIEF ONE...WILL
BE AT/AROUND 14Z AS SURFACE WARM FRONT LIFTS NORTHWARD. SOME
IMPROVEMENT IN CIGS IS STILL EXPECTED DURING THE AFTERNOON WITH A
BETTER FOOTHOLD INTO THE WARM SECTOR. THE POTENTIAL FOR
THUNDERSTORMS...WITH SOME POSSIBLY REACHING SEVERE
LIMITS...APPEARS TO BE PRIMARILY CENTERED AT/AROUND THE 01-03Z
TIME WINDOW. THE OTHER ITEM OF CONCERN THIS TAF PERIOD IS THE
STRONG POST COLD FRONTAL WEST WINDS THAT WILL INCREASE AFTER 09Z
TONIGHT. THE STRONGEST WIND POTENTIAL WILL OCCUR NORTH OF
INTERSTATE 69 WHERE WINDGUSTS OF 45 KNOTS WILL BE LIKELY.
FOR DTW...IFR/LIFR CIGS ARE SET TO DEVELOP OVER THE TERMINAL
SHORTLY AFTER THE START OF THE TAF PERIOD. POTENTIAL EXISTS FOR
FAIRLY INNOCUOUS SHOWER ACTIVITY BETWEEN 14-16Z. THERE IS LOW
CONFIDENCE IN VSBYS DROPPING TO 1/4SM WITH THE WARM FRONT THIS
MORNING. FAVORABLE TIME WINDOW FOR SHOWERS AND SCATTERED TSTORMS
IS BETWEEN 01-03Z THIS EVENING. STRONG POST FRONTAL WEST WINDS ARE
EXPECTED TO GUST TO 30 KNOTS AT DTW AFTER 09Z TONIGHT.
//DTW THRESHOLD PROBABILITIES...
* HIGH FOR CEILING BELOW 5000 FEET THROUGH TONIGHT.
* LOW FOR CIGS/VSBY BELOW 200FT AND/OR 1/2SM THIS MORNING.
* MODERATE TO HIGH FOR GUSTS EXCEEDING CROSSWIND THRESHOLD AFTER 09Z.
&&
.PREV DISCUSSION...ISSUED 337 AM EST WED DEC 23 2015
DISCUSSION...
LATEST WATER VAPOR IMAGERY SHOWS DEEPENING LONGWAVE TROUGH OVER
CENTRAL NORTH AMERICA...WITH THE FLOW OVER THE GULF COAST STATES
BACKING TO THE SOUTH. HOWEVER...THE LEAD MOISTURE ORIGINATING FROM
TENNESSEE/KENTUCKY IS EXPECTED TO SLIDE NORTHEAST INTO THE EASTERN
GREAT LAKES...PER 850 MB THETA-E FIELDS...WITH THE CORRESPONDING
NEGATIVE LI`S MOSTLY EAST...AND HAVE BACKED OFF ON THUNDERSTORM AND
POP MENTION THIS MORNING. STILL ENOUGH LOW LEVEL MOISTURE
ADVECTION/ISENTROPIC ASCENT AND EVENTUAL SATURATION TO TRIGGER
LIGHT RAIN/DRIZZLE AS THE DAY WEARS ON.
OUR FOCUS THIS EVENING/TONIGHT IS ON THE MOISTURE OVER EASTERN TEXAS
WHICH WILL BE ACCELERATING OFF TO THE NORTHEAST...AS EXPLOSIVE
CYCLOGENESIS (20 MB IN 24 HRS) EXPECTED TO TAKE PLACE.
DEEPENING SURFACE LOW TRACKS THROUGH THE WESTERN GREAT LAKES THIS
EVENING...AND NORTHEAST INTO JAMES BAY THURSDAY MORNING...AS
PHASING/CONSOLIDATION OF UPPER LEVEL PV (DAKOTAS/SOUTHERN PLAINS)
TAKES PLACE...DIRECTED AND SPED UP BY THE VERY STRONG UPPER LEVEL
WAVE/PV SLICING THROUGH THE PACIFIC NORTHWEST...HELPING TO FUEL
THE AGGRESSIVE DEVELOPMENT.
THE MOISTURE/CONVECTIVE AXIS LOOKS TO BE MOVING THROUGH SOUTHEAST
MICHIGAN AROUND MIDNIGHT...AND THE 00Z NAM IS INDICATING
CONSIDERABLE MORE INSTABILITY AS SURFACE BASED CAPES REACH TO AROUND
750 J/KG...WHILE THE GFS REMAINS MORE SUBDUED...STRUGGLING TO REACH
300 J/KG. INTERESTING...THE SURFACE DEW PT FORECAST FOR BOTH MODELS
ARE VERY CLOSE...SNEAKING INTO THE UPPER 50S. EVEN TAKING A BLEND OF
THE TWO SOLUTIONS..THE EXCEPTIONAL WIND FIELDS (50-55 KNOTS AT 925
MB/60+ KNOTS AT 850 MB) SUPPORT A DAMAGING WIND THREAT WITH ANY
VIGOROUS CONVECTION...WITH SEEMS LIKE A DECENT
POSSIBILITY/SCATTERED THUNDERSTORM COVERAGE...AS MID LEVEL LAPSE
(700-500 MB) LOOK TO BE AROUND 7 C/KM TO POSSIBLY AS HIGH AS 8
C/KM (SEE 00Z EURO). PLANNING ON INCLUDING DAMAGING WIND POTENTIAL
IN THE ZONES...AS LATEST SPC DAY 1 HAS TRENDED SOUTHEAST MICHIGAN
INTO THE MARGINAL TO SLIGHT CHANCE CATEGORIES NOW. STILL CAN`T
RULE OUT ISOLATED TORNADOES WITH EXTREME 0-1 KM BULK SHEAR (UP
NEAR 50 KNOTS) AND MUCH OF THE CAPE DENSITY DOWN LOW. VARIOUS
HIRES MODELS ARE GIVING MIXED SIGNALS...AND ARE INDICATING FASTER
ARRIVAL TIME OF CONVECTION DURING THE EARLY EVENING HOURS...WITH
OTHERS INDICATING MORE OF A MUTED RESPONSE THROUGH THE ENTIRE
NIGHT.
925 MB TEMPS INCREASING BETWEEN 13 TO 14 C TOWARD MIDNIGHT STILL
SUGGESTING LOWER 60S WILL BE NO PROBLEM...AND LOOKS LIKE WE WILL
DOUBLE DIP AND SET TWO DAYS OF RECORD HIGHS.
HIGH TEMPERATURE RECORDS FOR DECEMBER 23RD:
DTW 56 (1893)
FNT 55 (1982)
MBS 53 (1982)
DECEMBER 24TH
DTW 61 (1889)
FNT 56 (1982)
MBS 55 (1932)
PW VALUES AROUND 1.25 INCHES...850 MB DEW PTS 10+ C...CONTINUE TO
SUGGEST POTENTIAL RAINFALL AROUND HALF INCH...WITH
LOCALIZED/ISOLATED 1+ INCH TOTALS NOT OUT OF THE QUESTION.
THE ACTUAL COLD FRONTAL PASSAGE LOOKS TO BE TOWARD 12Z
THURSDAY...AND GOOD CHANCE LOCATIONS NORTH OF I-69 WILL SEE GUSTS OF
45+ MPH WITH SUBSIDENCE/COLD ADVECTION POP...AS 850 MB TEMPS CRASH
TO NEAR ZERO. ELECTED TO NOT ISSUE WIND ADVISORY AT THIS TIME...AS
FOCUS IS MORE ON SEVERE/DAMAGING WIND POTENTIAL...AND WE ARE TALKING
VERY LATE SECOND PERIOD.
UPPER LEVEL WEST-SOUTHWEST CONFLUENT FLOW THURSDAY-FRIDAY LOOKS TO
KEEP SOUTHEAST MICHIGAN MAINLY DRY...WITH TEMPERATURES STILL SOLIDLY
ABOVE NORMAL AND ABOVE FREEZING THE MAJORITY OF THE TIME.
PER 00Z EURO... IT LOOKS LIKE THE WEEKEND WILL FEATURE SPLIT UPPER
LEVEL FLOW..WITH CUTOFF UPPER LEVEL LOW OVER THE FOUR CORNERS
REGION...AND PROGRESSIVE NORTHERN STREAM SHORTWAVE TROUGH SLIDING
THROUGH THE GREAT LAKES ON SUNDAY. A WAVE OF LOW PRESSURE LOOKS TO
BE SCOOTING OFF TO THE NORTHEAST OUT OF THE SOUTHERN PLAINS/MIDWEST
ON SATURDAY...WITH THERMAL PROFILES SUGGESTING ALL RAIN FOR
SOUTHEAST MICHIGAN.
MARINE...
SURFACE LOW PRESSURE WILL RAPIDLY DEEPEN THIS EVENING TO 980 MB
WHILE TRACKING NORTHWARD ACROSS WISCONSIN AND LAKE SUPERIOR. A TIGHT
PRESSURE GRADIENT IS FORECASTED TO DEVELOP ALONG THE SOUTHEASTERN
FLANK OF THE LOW PRESSURE CENTER OVER LAKE MICHIGAN AND PORTIONS OF
NORTHERN LOWER MICHIGAN SIGNALING A HIGH POTENTIAL FOR STRONG WINDS.
TIMING OF THE STRONG COLD FRONT THROUGH THE STATE IS AFTER 09Z.
SOUTHEASTERLY WINDS WILL APPROACH GALE FORCE TODAY OVER THE OPEN
WATERS OF LAKE HURON. THE MOST IMPACTFUL PART OF THE LOW PRESSURE
SYSTEM WILL BE THE WESTERLY WINDS FORECASTED TO DEVELOP IN THE WAKE
OF THE COLD FRONT LATE TONIGHT AND THURSDAY. WHILE WESTERLY WINDS
ARE EXPECTED TO BE STRONG OVER ALL OF LAKE HURON...THE NORTH HALF OF
LAKE HURON WILL BE IN THE BETTER POSITION TO WITNESS WIND GUSTS TO
45 KNOT GALES. GALE WARNINGS HAVE BEEN ISSUED FOR ALL OF LAKE HURON.
RAPID MOVEMENT OF THE SURFACE LOW TO JAMES BAY...WITH A FAST
EVOLVING UPPER LEVEL PATTERN...SUPPORTS A RELATIVELY QUICK
DIMINISHING WIND TREND ALREADY THURSDAY AFTERNOON AND EVENING. WIND
GUSTS ARE EXPECTED TO DROP BELOW 20 KNOTS BY 06Z FRIDAY.
HYDROLOGY...
A LOW PRESSURE SYSTEM WILL STRENGTHEN TODAY WHILE TRACKING NORTHEAST
TO LAKE SUPERIOR. THE LOW PRESSURE SYSTEM WILL LIFT A STRONG WARM
FRONT THROUGH SOUTHERN MICHIGAN...BRINGING VERY WARM AND MOIST AIR
TO THE REGION. THERE WILL BE MULTIPLE OPPORTUNITIES FOR RAINFALL
TODAY...WITH THE POTENTIAL FOR BRIEF HEAVY RAINFALL IN POTENTIAL
THUNDERSTORM DEVELOPMENT WAITING UNTIL THE LATE AFTERNOON OR DURING
THE LATE EVENING HOURS. MOST LOCATIONS WILL SEE AROUND 0.5 INCHES OF
RAIN BY THURSDAY MORNING WITH ISOLATED TOTALS OF AROUND 1.0 INCH.
LITTLE CONCERN FOR FLOODING EXISTS.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...GALE WARNING FROM 3 AM TO NOON EST THURSDAY FOR LHZ421-422-441-462.
GALE WARNING FROM 4 AM TO 10 AM EST THURSDAY FOR LHZ442-443-463-464.
GALE WARNING FROM 7 PM THIS EVENING TO 3 PM EST THURSDAY FOR
LHZ361>363.
LAKE ST CLAIR...SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST THURSDAY
FOR LCZ460.
MICHIGAN WATERS OF LAKE ERIE...SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST THURSDAY
FOR LEZ444.
&&
$$
UPDATE.......DG
AVIATION.....CB
DISCUSSION...SF
MARINE.......CB
HYDROLOGY....CB
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION...UPDATED
NWS DULUTH MN
1145 AM CST WED DEC 23 2015
.UPDATE...
ISSUED AT 915 AM CST WED DEC 23 2015
UPDATED WEATHER TYPES FOR TODAY THROUGH 00Z. HAVE HAD REPORTS THIS
MORNING OF SLEET/RAIN MIX IN SOUTHERN WASHBURN COUNTY AND A
SNOW/RAIN MIX IN HAYWARD IN THE PAST FEW HOURS. STILL THINKING THE
COLUMN WILL COOL AND TREND TOWARD BETTER ICE CRYSTAL SEEDING
THROUGH THIS MORNING AS PRECIP RATES INCREASE...RESULTING IN
BETTER SNOW COVERAGE. HAVE INCLUDED A BIT MORE SLEET AND A
BROADER AREA OF RA/SN THROUGH THIS MORNING AND INTO THE AFTERNOON.
ALSO INCREASED COVERAGE OF DZ/FZDZ THROUGHOUT THE DAY IN AREAS NOT
EXPERIENCING THE HEAVIER PRECIPITATION. ALSO THREW IN A MENTION OF
FOG WHICH HAS BEEN OBSERVED AT SEVERAL SITES THIS MORNING.
UPDATE ISSUED AT 630 AM CST WED DEC 23 2015
MINOR UPDATE TO POPS AND WEATHER...IN GENERAL FORECAST REMAINS ON
TRACK WITH A LIGHT WINTRY MIX QUICKLY CHANGING TO MAINLY SNOW
WEST OF HIGHWAY 63 IN NW WISCONSIN AND MORE RAIN THAN SNOW EAST OF
HIGHWAY 63.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 427 AM CST WED DEC 23 2015
RAIN/SNOW WILL QUICKLY SPREAD ACROSS NORTHWEST WISCONSIN AND PARTS
OF NORTHEAST MINNESOTA TODAY RESULTING IN A QUICK FEW INCHES OF SNOW
FOR PARTS OF THE REGION. WHERE THE RAIN/SNOW LINE WILL BE IS STILL
DIFFICULT TO DETERMINE EVEN AT THIS SHORT TIME RANGE...BUT
CONFIDENCE HAS INCREASED IN COVERAGE OF PRECIPITATION /TRENDING
FARTHER WEST/ INTENSITY /HIGHER AMOUNTS/ AND RANGE OF PRECIP TYPES
EXPECTED /MAINLY JUST RAIN OR SNOW WITH LITTLE MIX/. RAIN/SNOW ENDS
QUICKLY FROM WEST TO EAST LATE TONIGHT WITH LINGERING FLURRIES
POSSIBLE INTO EARLY THURSDAY. WHEN IT IS ALL DONE THERE WILL LIKELY
BE A SWATH OF 2 TO 4 INCHES OF SNOW ACROSS A PORTION OF NORTHWEST
WISCONSIN...WITH OTHER LOCATIONS EXPERIENCE MAINLY RAIN ENDING AS
LIGHT SNOW.
ON THE SYNOPTIC SCALE A MID-LEVEL TROUGH AXIS WILL SWING NORTHEAST
FROM THE LOWER MISSOURI RIVER VALLEY INTO THE UPPER GREAT LAKES
TODAY. WHILE A POTENT LOW PRESSURE SYSTEM OVER THE RED RIVER VALLEY
MOVES NORTH INTO NORTHWEST ONTARIO IT WILL WEAKEN WHILE A STRONG AND
BROADER LOW PRESSURE DEVELOPS IN NORTHERN MISSOURI LATE THIS MORNING
MOVING NORTH-NORTHEAST INTO THE U.P. THIS EVENING. IN ADDITION TO
THE MID-LEVEL TROUGH A 120-130 KT JET STREAK DEVELOPS OVER THE
NORTHLAND LATE THIS MORNING RESULTING IN UPPER LEVEL DIVERGENCE
ACROSS NORTHERN WISCONSIN THIS AFTERNOON. FINALLY...WARM AIR
ADVECTION ONGOING AT LOW LEVELS HAS RAISED TEMPS TO THE MID 30S
ACROSS NORTHERN WISCONSIN WITH MODEL SOUNDINGS INDICATING A FAIRLY
WARM LAYER ALOFT...AS VERIFIED BY THE MPX 00Z SOUNDING. IN GENERAL
THE TREND IN GUIDANCE HAS BEEN A WESTWARD SHIFT AND STRONGER LARGE-
SCALE LIFT AS THE MID-LEVEL TROUGH RAPIDLY APPROACHES AND HEIGHTS
FALL THIS AFTERNOON. THE HRRR ACCENTUATES THIS TREND WITH RUNS THIS
MORNING COMING IN EVEN FURTHER WEST THAN MOST OF THE 00Z MODEL SUITE.
WHILE TEMPS ARE IN THE MID 30S ACROSS NORTHWEST WISCONSIN DEW POINTS
ARE STILL NEAR TO BELOW FREEZING...AND ONCE LOW LEVELS SATURATE
THINK THERE WILL BE A QUICK TRANSITION FROM LIGHT RAIN/DRIZZLE TO
SNOW ACROSS PARTS OF NORTHWEST WISCONSIN. THE RAIN/SNOW TRANSITION
LINE IS VERY CHALLENGING FOR TODAYS FORECAST WHICH RESULTS IN A
FAIRLY HIGH BUST POTENTIAL...BUT WITH THE LIKELIHOOD OF INTENSE
PRECIP AND TEMPS AT THE SFC AND THROUGH THE COLUMN COLD ENOUGH TO
SUPPORT SNOW BELIEVE THERE WILL BE A SWATH OF 2 TO 5 INCHES LATE
THIS MORNING INTO THE EARLY AFTERNOON. THUS...DECIDED TO GO WITH A
WINTER WX ADVISORY. THE RAIN/SNOW LINE LOOKS TO BE IN WESTERN
ASHLAND/SAWYER COUNTIES...AND DESPITE MOST OF THOSE COUNTIES
PROBABLY RECEIVING MAINLY RAIN TODAY THE FACT THAT /1/ THERE IS
STILL SOME UNCERTAINTY IN THIS FORECAST AND /2/ THE MOST POPULATED
CITIES IN EACH COUNTY ARE EXPECTED TO RECEIVE SNOW IS WHY WE DECIDED
TO ISSUE THE WINTER WX ADVISORY FOR THOSE COUNTIES. ON THE WEST
THERE WILL BE A SHARP CUT-OFF FOR WHERE THE ACCUMULATING SNOW
FALLS...WITH THIS LINE PROBABLY CLOSE TO THE TWIN PORTS. FOR NOW
HAVE 1 TO 3 INCHES OF SNOW FOR THE TWIN PORTS...THERE IS THE
POTENTIAL LITTLE IF ANY PRECIP OCCURS BUT DO NOT THINK THERE IS
POTENTIAL FOR MORE THAN THREE INCHES...SO DID NOT INCLUDE DULUTH IN
THE WINTER WX ADVISORY.
ELSEWHERE ACROSS NORTHEAST MINNESOTA...LIGHT SNOW WITH 1 TO 3 INCHES
IN THE ARROWHEAD..ELSEWHERE NOT MUCH DURING THE DAY BEFORE COLDER
AIR MOVES IN AND THE LOW MOVES NORTH INTO ONTARIO THIS EVENING
RESULTING IN LIGHT SNOW/FLURRIES LINGERING THROUGH EARLY THURSDAY.
EAST OF THE WINTER WX ADVISORY MAINLY RAIN TODAY WITH OVER A HALF
INCH LIKELY. RAIN CHANGES TO SNOW THIS EVENING FROM WEST TO
EAST...WITH A FEW INCHES OF SNOW POSSIBLE UNTIL THE SNOW ENDS
TOWARDS THURSDAY MORNING.
FINALLY...FOR THURSDAY AFTERNOON HIGH PRESSURE BUILDING IN ACROSS
THE MID MISSISSIPPI VALLEY COULD RESULT IN SOME PARTIAL CLEARING IN
CENTRAL MINNESOTA...BUT UNLIKELY GIVEN POTENT STRATUS DECK IN PLACE.
TEMPS FALL TO THE MID TEENS TO MID 20S TONIGHT AS PRECIP CHANGES
OVER TO SNOW...THEN ONLY CLIMBING AROUND 5 DEGREES TO THE 20S ON
THURSDAY AFTERNOON. WEST WINDS LATE TONIGHT INTO THURSDAY COULD BE
BREEZY FOR A TIME...THEN DIMINISH TOWARDS THURSDAY AFTERNOON.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 427 AM CST WED DEC 23 2015
THURSDAY NIGHT AND FRIDAY LOOK TO BE A QUIET LULL IN BETWEEN
SYSTEMS. THE MAIN QUESTION DURING THIS PERIOD WILL BE WHAT THE
CLOUD COVER DOES...AND ITS EFFECT ON TEMPERATURES. THE TREND THIS
TIME OF YEAR IS THAT UNLESS WE HAVE STRONG COLD DRY ADVECTION THAT
THOROUGHLY MIX OUT THE STRATUS...WE ARE LIKELY TO REMAIN STUCK IN
THE STRATUS IN BETWEEN THE SYSTEMS. SO...HAVE STAYED WITH A
CLOUDIER SOLUTION FOR NOW WITH NO GOOD STRONG PUSH TO GET RID OF THE
STRATUS AND HAVE STAYED WITH MODERATED TEMPERATURES THROUGHOUT.
HOWEVER...IF IT LOOKS LIKE WE MIGHT ACTUALLY CLEAR OUT AFTER
ALL...MY TEMPS ARE NOT COLD ENOUGH ALL AROUND. AS A FOOT
NOTE...HAVE NOTICED THE NAM RUNNING A WEAK FAST MOVING SHORTWAVE
ACROSS PARTS OF THE FORECAST AREA THURSDAY NIGHT...BUT IT IS THE
ONLY MODEL DOING THAT FOR NOW AND WHILE THE PREVIOUS RUNS HAVE
IT...THE TRACK HAS BEEN DRIFTING ABOUT AND REMAINS QUITE WEAK AND
MOSTLY SOUTH OF THE FORECAST AREA. SO...HAVE LEFT IT OUT FOR NOW.
THE NEXT SIGNIFICANT STORM MOVES THROUGH THE FORECAST AREA BEGINNING
FRIDAY NIGHT...AND CONTINUING SATURDAY BEFORE ENDING SATURDAY NIGHT
OR EARLY SUNDAY DEPENDING HOW MUCH LAKE EFFECT SNOW DEVELOPS. THE
MODELS ARE FAIRLY CONSISTENT IN BRINGING AN INVERTED SURFACE TROUGH
ACROSS THE FORECAST AREA DURING THE DAY ON SATURDAY...ASSOCIATED
WITH AN 850MB LOW THAT TRACKS FROM SE SD...EAST-NORTHEAST TO EASTERN
UPPER MICHIGAN DURING THE DAY ON SATURDAY. FOR NOW THIS KEEPS THE
FORECAST AREA IN BELOW ZERO TEMPERATURES ALOFT AND OUR PRECIPITATION
TYPE ALL SNOW...WITH NEAR TO A LITTLE HIGHER THAN NORMAL SNOW WATER
RATIOS FOR DECEMBER. MY INITIAL THOUGHTS BRING A SOLID 2 TO 4
INCHES ACROSS THE FORECAST AREA DURING THE EVENT...BUT WILL HAVE TO
WAIT AND SEE HOW THIS ONE DEVELOPS.
IT LOOKS LIKE ANOTHER STORM SYSTEM IS GOING TO MOVE ACROSS THE
MIDWEST ON MONDAY THROUGH TUESDAY...BRINGING ANOTHER CHANCE FOR
PRECIPITATION TO THE REGION. HOWEVER...THE LATEST MODELS ARE
KEEPING THIS SYSTEM MAINLY SOUTH OF THE FORECAST AREA AND HAVE PUT
IN LOWER POPS THAN WHAT WE PREVIOUSLY HAD TO TREND TOWARDS A DRIER
FORECAST. WILL HAVE TO SEE IF THIS TREND CONTINUES BEFORE REMOVING
THEM COMPLETELY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1140 AM CST WED DEC 23 2015
EXPECT IFR TO LIFR WITH CIGS BLO OVC010 AND VSBYS LESS THAN 1/2SM
IN MAINLY LIGHT SNOW AND FOG FOR MOST OF THE AREA. THESE
CONDITIONS WILL CONTINUE FOR MUCH OF THE PERIOD...UNTIL AFT 12Z
WHEN CONDITIONS WILL IMPROVE TO MVFR. THE EXCEPTION WILL BE IN THE
KBRD AREA WHERE CURRENT VFR CONDITIONS WILL LOWER TO MVFR AND
MAYBE IFR CONDITIONS LATER THIS AFTERNOON WITH SOME OCNL -SN.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 34 20 24 15 / 90 70 10 10
INL 34 21 23 11 / 20 50 30 10
BRD 33 18 24 15 / 20 10 10 0
HYR 34 23 28 15 / 100 100 20 10
ASX 36 26 29 20 / 100 100 20 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR
WIZ001>003-006>008.
MN...NONE.
LS...SMALL CRAFT ADVISORY FROM 2 AM TO 6 PM CST THURSDAY FOR LSZ121-
140>148.
&&
$$
UPDATE...HUYCK
SHORT TERM...JJM
LONG TERM...LE
AVIATION...CLC
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
125 PM CST WED DEC 23 2015
.UPDATE:
Issued at 122 PM CST Wed Dec 23 2015
In the process of issuing a wind advisory for our mid MO counties.
Passage of cold front/dry line has been accompanied by deep
mixing over southwest and west central MO with sustained winds of
25-30kts, and expecting similar conditions to spread over western
portions of our CWA as fropa occurs during the afternoon.
Otherwise, no changes to earlier thinking, and still anticipating
strong convection to fire along the cold front/dry line over the
next 1-2 hours.
Truett
&&
.SHORT TERM: (Through Tonight)
Issued at 344 AM CST Wed Dec 23 2015
Showers and thunderstorms will be on the increase this morning as
surface low and associated upper level trof continue to lift north
northeast from TX panhandle towards the western Great Lakes region
by early this evening. Forecast area to remain on warm side of
system through midday before strong cold front slides through
region. Main question is will this initial round of activity muddy
the waters for any severe convection with frontal boundary this
afternoon. Think there will be enough of break in precipitation and
clouds to see atmosphere become unstable with CAPES between 500 and
1200 J/kg as strong low level jet advects dewpts in the upper 50s to
low 60s into the region by this afternoon. Forecast soundings
continue to indicate deep layer shear, curved hodographs and this
combined with decent instability, supercell development is expected
with the main threats being tornadoes and damaging winds, though
some large hail is possible as well. The best area to see this would
be southeast MO and southwestern IL. However, latest HRRR run is
indicating some supercell development further north closer to
deepening surface low over northeast MO and west central IL. Will
have to keep an eye out on these changing conditions.
Otherwise, will see temperatures rising through midday on gusty
south winds, into the 60s, then remain steady or slowly fall as
frontal boundary slides through. Could see gusts between 35 and 40
mph at times outside of storms. Storms to taper off by early this
evening with winds veering to the west on back side of system and
diminishing.
Byrd
.LONG TERM: (Thursday through Tuesday)
Issued at 344 AM CST Wed Dec 23 2015
(Thursday through Christmas Day)
Dry weather expected for most of the area through Christmas Day with
temperatures remaining above normal, in the upper 40s to low 60s.
With stalled frontal boundary just south of forecast area, could see
some light rain for far southern portions of forecast area Christmas
Day.
(Christmas Night through Tuesday)
Frontal boundary that is stalled south of the forecast area will
move back northward Christmas night and Saturday. Will see numerous
rounds of showers and embedded thunderstorms across the region
through Monday before tapering off Monday night as associated
surface low lifts northeastward through region and into the Great
Lakes region by Monday night. At this time, models are indicating
between 3 and 6 inches of rain with locally higher amounts possible.
The axis of heaviest rain will extend from southwestern MO
through the St. Louis metro area and into central Illinois. This
will affect area rivers and streams, leading to additional
flooding. For more details, please see the hydrologic outlook
(ESF).
Byrd
&&
.AVIATION: (For the 18z TAFs through 18z Thursday Afternoon)
Issued at 1128 AM CST Wed Dec 23 2015
Morning thunderstorms have moved rapidly east of all TAF sites.
However...another line of thunderstorms is forecast to form around
19Z near a KCOU to KUIN line and move rapidly eastward into the
KSTL metro TAF sites between 21Z and 23Z. Coverage is uncertain at
this time...so covered in 18Z TAFS with VCTS. Will update as
needed once convection forms. Some storms could produce strong
wind gusts. Behind that line...VFR conditions expected and
southwest winds will likely increase for a few hours with gusts to
near 30 kts. Winds will diminish during the evening...and veer
strongly to southeast by 12Z.
Specifics for KSTL: Morning thunderstorms have moved rapidly east
with VFR conditions remaining. However...another line of
thunderstorms is forecast to move rapidly eastward into the KSTL
metro TAF sites between 21Z and 23Z. Coverage is uncertain at this
time...so covered in 18Z TAFS with VCTS. Will update as needed
once convection forms. Some storms could produce strong wind
gusts. Behind that line...VFR conditions expected and southwest
winds will likely increase for a few hours with gusts to near 30
kts. Winds will diminish during the evening...and veer strongly to
southeast by 12Z...then back to 180 degrees by around 18Z.
Browning
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...Wind Advisory until 6 PM CST this evening FOR Audrain MO-Boone
MO-Callaway MO-Cole MO-Gasconade MO-Moniteau MO-Montgomery
MO-Osage MO.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
1205 PM CST WED DEC 23 2015
.UPDATE:
Issued at 1159 AM CST Wed Dec 23 2015
Current line of convection over the southeast sections of the CWA will
continue to roll east and exit the area early this afternoon, just
in time for another round of strong to potentially severe storms
to develop along the eastward pushing cold front/dry line. Clearing
ahead of the front/dry line is rapidly destabilzing the AMS, and
RAP forecasts throughout the morning have consistently been
forecasting SBCAPES of 1000-1500 J/Kg into the afternoon hours.
Truett
&&
.SHORT TERM: (Through Tonight)
Issued at 344 AM CST Wed Dec 23 2015
Showers and thunderstorms will be on the increase this morning as
surface low and associated upper level trof continue to lift north
northeast from TX panhandle towards the western Great Lakes region
by early this evening. Forecast area to remain on warm side of
system through midday before strong cold front slides through
region. Main question is will this initial round of activity muddy
the waters for any severe convection with frontal boundary this
afternoon. Think there will be enough of break in precipitation and
clouds to see atmosphere become unstable with CAPES between 500 and
1200 J/kg as strong low level jet advects dewpts in the upper 50s to
low 60s into the region by this afternoon. Forecast soundings
continue to indicate deep layer shear, curved hodographs and this
combined with decent instability, supercell development is expected
with the main threats being tornadoes and damaging winds, though
some large hail is possible as well. The best area to see this would
be southeast MO and southwestern IL. However, latest HRRR run is
indicating some supercell development further north closer to
deepening surface low over northeast MO and west central IL. Will
have to keep an eye out on these changing conditions.
Otherwise, will see temperatures rising through midday on gusty
south winds, into the 60s, then remain steady or slowly fall as
frontal boundary slides through. Could see gusts between 35 and 40
mph at times outside of storms. Storms to taper off by early this
evening with winds veering to the west on back side of system and
diminishing.
Byrd
.LONG TERM: (Thursday through Tuesday)
Issued at 344 AM CST Wed Dec 23 2015
(Thursday through Christmas Day)
Dry weather expected for most of the area through Christmas Day with
temperatures remaining above normal, in the upper 40s to low 60s.
With stalled frontal boundary just south of forecast area, could see
some light rain for far southern portions of forecast area Christmas
Day.
(Christmas Night through Tuesday)
Frontal boundary that is stalled south of the forecast area will
move back northward Christmas night and Saturday. Will see numerous
rounds of showers and embedded thunderstorms across the region
through Monday before tapering off Monday night as associated
surface low lifts northeastward through region and into the Great
Lakes region by Monday night. At this time, models are indicating
between 3 and 6 inches of rain with locally higher amounts possible.
The axis of heaviest rain will extend from southwestern MO
through the St. Louis metro area and into central Illinois. This
will affect area rivers and streams, leading to additional
flooding. For more details, please see the hydrologic outlook
(ESF).
Byrd
&&
.AVIATION: (For the 18z TAFs through 18z Thursday Afternoon)
Issued at 1128 AM CST Wed Dec 23 2015
Morning thunderstorms have moved rapidly east of all TAF sites.
However...another line of thunderstorms is forecast to form around
19Z near a KCOU to KUIN line and move rapidly eastward into the
KSTL metro TAF sites between 21Z and 23Z. Coverage is uncertain at
this time...so covered in 18Z TAFS with VCTS. Will update as
needed once convection forms. Some storms could produce strong
wind gusts. Behind that line...VFR conditions expected and
southwest winds will likely increase for a few hours with gusts to
near 30 kts. Winds will diminish during the evening...and veer
strongly to southeast by 12Z.
Specifics for KSTL: Morning thunderstorms have moved rapidly east
with VFR conditions remaining. However...another line of
thunderstorms is forecast to move rapidly eastward into the KSTL
metro TAF sites between 21Z and 23Z. Coverage is uncertain at this
time...so covered in 18Z TAFS with VCTS. Will update as needed
once convection forms. Some storms could produce strong wind
gusts. Behind that line...VFR conditions expected and southwest
winds will likely increase for a few hours with gusts to near 30
kts. Winds will diminish during the evening...and veer strongly to
southeast by 12Z...then back to 180 degrees by around 18Z.
Browning
&&
.PRELIMINARY POINT TEMPS/POPS:
Saint Louis 68 43 56 38 / 80 30 5 10
Quincy 65 37 47 33 / 70 30 10 5
Columbia 67 38 53 35 / 50 10 5 5
Jefferson City 69 38 55 36 / 50 10 5 10
Salem 67 45 57 40 / 100 60 5 10
Farmington 67 42 59 39 / 80 20 5 10
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1143 AM CST WED DEC 23 2015
.SHORT TERM: (Through Tonight)
Issued at 344 AM CST Wed Dec 23 2015
Showers and thunderstorms will be on the increase this morning as
surface low and associated upper level trof continue to lift north
northeast from TX panhandle towards the western Great Lakes region
by early this evening. Forecast area to remain on warm side of
system through midday before strong cold front slides through
region. Main question is will this initial round of activity muddy
the waters for any severe convection with frontal boundary this
afternoon. Think there will be enough of break in precipitation and
clouds to see atmosphere become unstable with CAPES between 500 and
1200 J/kg as strong low level jet advects dewpts in the upper 50s to
low 60s into the region by this afternoon. Forecast soundings
continue to indicate deep layer shear, curved hodographs and this
combined with decent instability, supercell development is expected
with the main threats being tornadoes and damaging winds, though
some large hail is possible as well. The best area to see this would
be southeast MO and southwestern IL. However, latest HRRR run is
indicating some supercell development further north closer to
deepening surface low over northeast MO and west central IL. Will
have to keep an eye out on these changing conditions.
Otherwise, will see temperatures rising through midday on gusty
south winds, into the 60s, then remain steady or slowly fall as
frontal boundary slides through. Could see gusts between 35 and 40
mph at times outside of storms. Storms to taper off by early this
evening with winds veering to the west on back side of system and
diminishing.
Byrd
.LONG TERM: (Thursday through Tuesday)
Issued at 344 AM CST Wed Dec 23 2015
(Thursday through Christmas Day)
Dry weather expected for most of the area through Christmas Day with
temperatures remaining above normal, in the upper 40s to low 60s.
With stalled frontal boundary just south of forecast area, could see
some light rain for far southern portions of forecast area Christmas
Day.
(Christmas Night through Tuesday)
Frontal boundary that is stalled south of the forecast area will
move back northward Christmas night and Saturday. Will see numerous
rounds of showers and embedded thunderstorms across the region
through Monday before tapering off Monday night as associated
surface low lifts northeastward through region and into the Great
Lakes region by Monday night. At this time, models are indicating
between 3 and 6 inches of rain with locally higher amounts possible.
The axis of heaviest rain will extend from southwestern MO
through the St. Louis metro area and into central Illinois. This
will affect area rivers and streams, leading to additional
flooding. For more details, please see the hydrologic outlook
(ESF).
Byrd
&&
.AVIATION: (For the 18z TAFs through 18z Thursday Afternoon)
Issued at 1128 AM CST Wed Dec 23 2015
Morning thunderstorms have moved rapidly east of all TAF sites.
However...another line of thunderstorms is forecast to form around
19Z near a KCOU to KUIN line and move rapidly eastward into the
KSTL metro TAF sites between 21Z and 23Z. Coverage is uncertain at
this time...so covered in 18Z TAFS with VCTS. Will update as
needed once convection forms. Some storms could produce strong
wind gusts. Behind that line...VFR conditions expected and
southwest winds will likely increase for a few hours with gusts to
near 30 kts. Winds will diminish during the evening...and veer
strongly to southeast by 12Z.
Specifics for KSTL: Morning thunderstorms have moved rapidly east
with VFR conditions remaining. However...another line of
thunderstorms is forecast to move rapidly eastward into the KSTL
metro TAF sites between 21Z and 23Z. Coverage is uncertain at this
time...so covered in 18Z TAFS with VCTS. Will update as needed
once convection forms. Some storms could produce strong wind
gusts. Behind that line...VFR conditions expected and southwest
winds will likely increase for a few hours with gusts to near 30
kts. Winds will diminish during the evening...and veer strongly to
southeast by 12Z...then back to 180 degrees by around 18Z.
Browning
&&
.PRELIMINARY POINT TEMPS/POPS:
Saint Louis 68 43 56 38 / 80 30 5 10
Quincy 64 37 47 33 / 80 30 10 5
Columbia 67 38 53 35 / 50 10 5 5
Jefferson City 69 38 55 36 / 50 10 5 10
Salem 67 45 57 40 / 100 60 5 10
Farmington 67 42 59 39 / 80 20 5 10
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1128 AM CST WED DEC 23 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 332 AM CST WED DEC 23 2015
RADAR HAS AREAS OF LIGHT RAIN MOVING THROUGH THE EASTERN PART OF THE
FORECAST AREA EARLY THIS MORNING. TEMPERATURES IN THE AREA OF RAIN
ARE WARM ENOUGH AT THIS TIME TO CONTINUE TO BE RAIN. TO THE WEST OF
THE RAIN THE TEMPERATURES HAVE STARTED TO COOL OFF.
THROUGH DAYBREAK AND INTO THE MORNING HOURS AN UPPER LEVEL LOW IS
MOVING THROUGH THE AREA. EVEN THOUGH IT IS IN THE FIRST FEW HOURS OF
THE FORECAST...THERE ARE A FEW DIFFERENCES. THE HRRR AND RAP KEEP
PRECIPITATION ONLY IN THE FAR EAST WHILE THE 4KM WRF...NAM AND GFS
PUSH THE PRECIPITATION FURTHER TO THE EAST. THE BEST CHANCE WILL
DEFINITELY BE IN THE EAST...BUT HAVE KEPT SOME LOWER POPS FURTHER TO
THE WEST. THIS BRINGS IN A PROBLEM FOR PRECIPITATION TYPE. WHILE THE
TEMPERATURES ALOFT ARE WARM ENOUGH FOR RAIN...SO IS THE SURFACE.
ONCE THE TEMPERATURES ALOFT COOL OFF THE SURFACE DOES AS
WELL...MAKING A CHANGE TO SNOW. HAVE KEPT A RAIN AND SNOW MIX IN THE
WEST/NORTHWEST THROUGH DAY BREAK AND INTO THE MORNING HOURS AS THE
PRECIPITATION IS MOVING OUT OF THE AREA. BY MID DAY THE UPPER LOW
HAS MOVED EAST AND EXPECT THAT PRECIPITATION SHOULD COME TO AN END.
THERE WILL ALSO BE SOME CLEARING AND A LITTLE SUNSHINE FOR A TIME
THIS AFTERNOON.
THE NEXT UPPER LEVEL WAVE WILL BE MOVING INTO THE AREA TONIGHT.
EXPECT PRECIPITATION TO MOVE INTO THE AREA FROM THE SOUTHWEST
TONIGHT. TEMPERATURES ARE EXPECTED TO BE COLD ENOUGH THAT EXPECT
SNOW ACROSS THE ENTIRE AREA. THE BEST CHANCE FOR ACCUMULATING SNOW
WILL BE MAINLY LATE TONIGHT. THROUGH MORNING...EXPECT THERE TO BE
LESS THAN AN INCH OR LESS OF SNOW.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 347 AM CST WED DEC 23 2015
THE MID AND LONG TERM FORECASTS CONTINUE TO BE INTERESTING AND
CHALLENGING.
CHRISTMAS EVE - CHRISTMAS NIGHT:
THERE MAY BE SOME LINGERING SNOW ACROSS THE AREA EARLY THURSDAY
MORNING...BUT EXPECT IT TO MOVE OFF OVER EASTERN NEBRASKA BY MID
MORNING. SKIES ARE EXPECTED TO CLEAR AND HIGHS...IF NOT IMPACTED
MUCH BY ANY SNOW ACCUMULATION OVERNIGHT WILL REACH INTO THE 30S TO
LOW 40S.
ON CHRISTMAS DAY A PIECE OF THE MAIN DISTURBANCE THAT WILL IMPACT
THE REGION FOR THE WEEKEND INTO EARLY NEXT WEEK WILL BREAK OFF AND
MOVE NORTHEAST ACROSS THE AREA. THIS WILL BRING THE POSSIBILITY
FOR PRECIPITATION MAINLY ACROSS NORTHERN NEBRASKA...BUT SOME COULD
CREEP INTO CENTRAL NEBRASKA DURING THE LATE AFTERNOON AND
OVERNIGHT. HIGHS WILL BE SIMILAR TO THURSDAY.
SATURDAY - TUESDAY:
THIS PERIOD IS THE MOST CHALLENGING. THE GUIDANCE HAS EVOLVED FROM
LAST NIGHT`S...GIVING A SLOWER SOLUTION...TRENDING TOWARDS LAST
NIGHTS ECMWF. THE SLOWER/FURTHER SOUTH ROUTE IS IMPACTING THE
AREA OF PRECIPITATION POTENTIAL. CONFIDENCE ON THIS PART OF THE
FORECAST IS RELATIVELY LOW. CONFIDENCE IS HIGH THAT A SYSTEM WILL
IMPACT THE CENTRAL AND SOUTHERN PLAINS...BUT THE DETAILS OF WHEN
AND WHERE ARE STILL VERY UNCLEAR.
WHILE LAST NIGHT`S FORECAST HAD SATURDAY NIGHT THROUGH SUNDAY IN
THE PERIOD WITH THE BEST CHANCES FOR ACCUMULATING SNOW...THIS HAS
CHANGED...WITH SUNDAY NIGHT INTO TUESDAY WITH THE LARGER CONCERN.
THIS IS NOT OVERLY UNEXPECTED WITH THE SLOWER SOLUTION. SO AS TO
NOT FLIP FLOP ON THE FORECAST HAVE KEPT PRECIPITATION CHANCES FOR
SATURDAY AND SUNDAY...BUT WITH THE CURRENT GUIDANCE...CHANCES ARE
MUCH LESS. A COLD FRONT WILL MOVE THROUGH VERY EARLY SATURDAY
MORNING WHICH WILL DROP TEMPERATURES WITH BREEZY NORTH WINDS. THIS
WILL CAUSE HIGHS FOR THE REMAINDER OF THE FORECAST TO BE IN THE
20S.
THE GFS DID SLOW TO CONVERGE ON A SOLUTION SIMILAR TO THE
ECMWF...BUT IT STILL EJECTS THE DISTURBANCE NORTHEASTWARD QUICKER
ON MONDAY MORNING. WHEREAS THE ECMWF PULLS THE UPPER LOW AND
ASSOCIATED SURFACE LOW ACROSS THE AREA MONDAY NIGHT INTO TUESDAY.
THE SLOWER SOLUTION ALLOWS THE TEMPERATURES TO REMAIN COLD ENOUGH
THROUGHOUT THE COLUMN FOR SNOW TO BE THE MAIN PRECIPITATION TYPE
AFTER THE TRANSITION WITH THE COLD FRONT ON SATURDAY THROUGH THE
REMAINDER OF THE WEEKEND INTO EARLY NEXT WEEK.
DUE TO THE LOW CONFIDENCE WITH MODEL DISCREPANCIES...STILL THINK
SOME TRAVEL THROUGH THE CENTRAL AND SOUTHERN PLAINS WILL BE
HAZARDOUS FOR PORTIONS OF THE HOLIDAY WEEKEND. IT IS STILL TOO
EARLY TO SPECULATE ON SNOW ACCUMULATIONS...ESPECIALLY WITH THE
MODEL CHANGES...BUT SNOW ACCUMULATION IS POSSIBLE THIS WEEKEND
INTO THE BEGINNING OF THE WEEK. STAY TUNED TO THE FORECASTS AS IT
CONTINUES TO EVOLVE AND THE DETAILS ARE REFINED.
&&
.AVIATION...(FOR THE 18Z KGRI/KEAR TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1124 AM CST WED DEC 23 2015
CLEARING SKIES AND VFR CONDITIONS HAVE BASICALLY SETTLED INTO
KGRI/KEAR AND WILL CONTINUE THROUGH THE AFTERNOON. WINDS WILL
BE IN THE 15KT RANGE BUT DROP OFF QUICKLY NEAR SUNSET. NEXT
WEATHER SYSTEM WILL SPREAD LIGHT SNOW ACROSS SOUTHERN NEBRASKA
AND NORTHERN KANSAS OVERNIGHT...MAINLY AFTERNOON MIDNIGHT...
WHICH WILL LIKELY RESULT IN MVFR VISIBILITIES AND CEILINGS FOR
TIME AT BOTH SITES.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...JCB
LONG TERM...BILLINGS WRIGHT
AVIATION...NOAA/NWS/MORITZ
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
300 PM EST WED DEC 23 2015
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE OFFSHORE THROUGH THE WEEKEND. A WEAK
COLD FRONT WILL APPROACH FROM THE NORTH THURSDAY NIGHT THEN STALL
NEAR THE VIRGINIA BORDER FRIDAY. THE FRONT WILL LIFT BACK NORTH
OVER THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 1020 AM WEDNESDAY...LATE MORNING UPDATE FOR ONLY MINOR
TWEAKS IN THE NEAR TERM. CONVECTION HAS SHOWN POTENTIAL TO BECOME
SEVERE FOR WESTERN ZONES (DUPLIN/ONSLOW/GREENE/LENOIR COUNTIES)
WHERE SPC MESOANALYSES INDICATE BETTER INSTABILITY. IR SATELLITE
IMAGERY INDICATED WARMING CLOUD TOPS AS THE EARLIER CONVECTION
SHIFTS NORTH ACROSS THE HWY 64 CORRIDOR. A PERIOD OF HEAVY RAIN
AND POSSIBLY GUSTY WINDS WILL STILL BE POSSIBLE INTO EARLY
AFTERNOON WITH SHOWER COVERAGE INCREASING FROM THE SOUTH AND WEST.
THE SYNOPTIC PATTERN PRESENTS AN UPPER TROUGH MOVING INTO THE
PLAINS WITH RIDGING OVER THE ATLANTIC, BRINGING DEEP SW FLOW
ACROSS THE EASTERN CONUS THAT IS TAPPING INTO TROPICAL PACIFIC
MOISTURE BRINGING PWATS AROUND 1.75 INCHES WHICH IS AT OR ABOVE
CLIMATOLOGICAL MAXIMUM FOR LATE DECEMBER. SFC HIGH PRES REMAINS
CENTERED OFFSHORE WITH A COASTAL TROUGH JUST SOUTH OF THE REGION
PROGGED TO LIFT ACROSS THE REGION TODAY. THIS PATTERN WILL
CONTINUE TO BRING PERIODS OF SHOWERS ACROSS THE REGION TODAY WHICH
ARE BEING ENHANCED BY WEAK EMBEDDED SHORTWAVES MOVING THROUGH THE
FLOW ALOFT. COULD SEE A FEW STRONGER STORMS DEVELOP THROUGH THE
AFTERNOON HOURS AS THE AIRMASS DESTABILIZES IN THE PRESENCE OF
STRONG LOW LEVEL SHEAR. HRRR IS FORECASTING MLCAPE AROUND
1000-1500J/KG AND LI`S AROUND -4C WITH 40-50 KT 0-6KM SHEAR AND
0-1KM HELICITY AROUND 200-300 M2/S2 THIS AFTERNOON WITH HIGHEST
VALUES WEST OF HIGHWAY 17. SPC HAS MOST OF THE REGION OUTLOOKED
FOR A MARGINAL RISK OF SEVERE THUNDERSTORMS WITH DAMAGING WIND
GUSTS AND AN ISOLATED TORNADO THE PRIMARY THREAT. PERIODS OF HEAVY
RAINFALL WITH LOCALIZED FLOODING OF POOR DRAINAGE AND LOW LYING
AREA WILL ALSO BE POSSIBLE. EXPECT GUSTY SLY WINDS TO DEVELOP LATE
MORNING THROUGH THE AFTERNOON IN THE WAKE OF THE TROUGH LIFTING
ACROSS THE REGION WHICH COULD BRING GUSTS AROUND 20-30 MPH. TEMPS
WILL BE ALMOST 20 DEGREES ABOVE NORMAL WITH HIGHS EXPECTED IN THE
MID 70S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/...
AS OF 3 AM WEDNESDAY....LITTLE CHANGE IN THE PATTERN TONIGHT WITH
MOIST SW FLOW CONTINUING. A FEW STRONGER STORMS WILL BE POSSIBLE
EARLY IN THE EVENING BUT GENERALLY EXPECT A DECREASE IN COVERAGE
THROUGH THE OVERNIGHT AS SHORTWAVE ENERGY LIFTS NORTH OF THE
REGION AND THE UPPER RIDGE OVER THE WESTERN ATLANTIC BEGINS TO
BUILDS WEST SOME. WILL CONTINUE A DECREASING TREND IN POPS THROUGH
THE OVERNIGHT. MODERATE SLY WINDS WILL BRING VERY MILD OVERNIGHT
TEMPS IN THE UPPER 60S TO 70...WHICH IS ABOUT 30-35 DEGREES ABOVE
NORMAL AND WILL LIKELY BREAK RECORD HIGH MINIMUM TEMPERATURES FOR
THE DAY...SEE CLIMATE SECTION BELOW.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
AS OF 300 PM WED...EXPECT RECORD BREAKING WARMTH THROUGH MUCH OF
THE PERIOD AS STRONG UPPER RIDGE OVER THE ATLANTIC BUILDS WEST
TOWARD THE COAST INTO THE WEEKEND.
THURSDAY NIGHT THROUGH CHRISTMAS DAY...COVERAGE OF PRECIPITATION
WILL DROP A BIT THURSDAY NIGHT AND FRIDAY AS UPR RDG GRAD BUILDS
W. UPR RDG BUILDS CLOSER WHICH WILL ACT TO SUPPRESS CONVECTION
AND WITH MORE SUN TEMPS WILL AGAIN BE VERY WARM REACHING AROUND 80
WARMER SPOTS ON CHRISTMAS DAY.
SATURDAY THROUGH SUNDAY...STRONG UPPER LEVEL RIDGE HOLDS ACROSS
THE SOUTHEASTERN UNITED STATES THROUGH THE WEEKEND AS LOW
PRESSURE MOVES FROM THE MISSISSIPPI VALLEY INTO THE GREAT LAKES
REGION. THIS WILL KEEP UNSEASONABLY WARM TEMPERATURES IN PLACE
WITH DAYTIME HIGHS WELL INTO THE 70S SATURDAY AND SUNDAY WITH LOWS
IN THE 60S. THERE WILL BE ONLY A SMALL CHANCE OF SHOWERS EACH DAY
GIVEN THE CONTINUED RATHER MOIST AIRMASS WITH FORECAST
PRECIPITABLE WATER VALUES AOA 1.50 INCHES.
MONDAY THROUGH WEDNESDAY...UPR RDG WILL BEGIN TO SHIFT BACK E
WITH MDLS SHOWING BACKDOOR FRONT DROPPING INTO THE REGION LATE
SUNDAY NIGHT OR EARLY MON THEN LIFTING BACK N TUE AHEAD OF
STRONGER APPROACHING FRONT. CONT PREV FCST OF CHC POPS EARLY NEXT
WEEK WITH STILL VERY MILD TEMPS IN THE 60S TO LOWER 70S...POSS
SOME MID 70S TUE/WED. A COLD FRONT APPROACHES FROM THE WEST ON
WEDNESDAY BUT TIMING OF THE FRONTAL PASSAGE VERY MUCH IN QUESTION
GIVEN THE POTENTIAL ERROR IN THE DAY 7 FORECAST. WILL CONTINUE
WITH ABOVE NORMAL TEMPS AND CHC POPS THRU MIDWEEK FOR NOW.
&&
.AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
SHORT TERM /THROUGH TONIGHT/...
AS OF 1 PM WEDNESDAY...HIGH CONFIDENCE OF MVFR CONDITIONS WILL
PERSIST MOST OF THE TAF PERIOD. WITH A MOIST SW FLOW...PERIODS OF
SHOWERS WILL CONTINUE ACROSS THE AREA. SOME STORMS COULD BE
STRONG TO MARGINALLY SEVERE THIS AFTERNOON IF INSTABILITY CAN BE
REALIZED WITH STRONG SHEAR IN PLACE AND SHORTWAVE ENERGY MOVING
ACROSS THE REGION. THESE SHOWERS/THUNDERSTORMS ARE EXPECT TO BRIEFLY
REDUCE VSBYS/CEILINGS. SOUTHERLY WINDS 10-15 KTS WITH GUSTS 20 TO
25 KNOTS REDUCING DOWN TO AROUND 10 KTS OVERNIGHT. FORECASTING
SOUNDING AND GUIDANCE CONTINUES TO SHOW MVFR CEILINGS FOR TONIGHT
AND REDUCING DOWN TO IFR CEILINGS AROUND 7/8Z. CEILINGS ARE
EXPECTED TO INCREASE BACK TO MVFR THURS MORNING WITH WIND GUST
INCREASING BACK AGAIN.
LONG TERM /THU NIGHT THROUGH MONDAY/...
AS OF 300 PM WED...WITH STRONG UPPER RIDGE BUILDING OVER THE AREA,
THE COVERAGE OF SHRA/TSRA WILL BE LIMITED THRU MUCH OF THE
UPCOMING WEEKEND. HOWEVER WITH LOW LEVELS REMAINING VERY MOIST
BOUTS OF SUB VFR STRATUS AND FOG WILL BE LIKELY LATE NIGHT/EARLY
MORN THRU SUNDAY. MAINLY VFR LATE MORN THRU EVENING HOURS WITH
ONLY SMALL CHC OF SHRA/TSRA THRU THE WEEKEND. A BACK DOOR COLD
FRONT DROPS THRU THE AREA LATE SUNDAY NIGHT OR EARLY MONDAY
BRINGING A POTENTIAL FOR LOW CLOUDS AND FOG BEHIND THE FRONT EARLY
NEXT WEEK.
&&
.MARINE...
SHORT TERM /THROUGH TONIGHT/
AS OF 1025 AM WEDNESDAY...LATEST SURFACE AND BUOY DATA INDICATE SE
TO SSW WINDS ACROSS THE EASTERN NC WATERS 5-15 KT WITH GUSTS NEAR
20 KT FOR THE OUTER BUOYS 41025/41064. THE SURFACE RIDGE REMAINS
CENTERED OFF THE SOUTHEAST COAST THROUGH THE SHORT TERM. A COASTAL
TROUGH JUST SOUTH OF THE WATERS IS PROGGED TO LIFT ACROSS THE
REGION THIS MORNING. SE WINDS AROUND 5-15 KT WILL BECOME SLY AND
INCREASE TO 15-25 KT WITH HIGHER GUSTS AFTER THE TROUGH LIFTS
ACROSS THE REGION AND CONTINUE THROUGH MUCH OF THE OVERNIGHT. SEAS
CURRENTLY AROUND 3-6 FT WILL BUILD IN RESPONSE TO THE STRONGER SLY
FLOW THROUGH THE DAY...PEAKING AROUND 6-10 FT TONIGHT. STRONGEST
WINDS/SEAS WILL OCCUR OVER THE COASTAL WATERS AND WILL CONTINUE
THE SCA. THE SOUNDS AND RIVERS EXPECTED TO REMAIN JUST BELOW
ADVISORY CRITERIA BUT MAY BE CLOSE ACROSS THE PAMLICO SOUND,
ESPECIALLY IN GUSTS.
LONG TERM /THU NIGHT THROUGH MONDAY/...
AS OF 300 PM WED...SW WINDS AND ELEVATED SEAS WILL GRAD SUBSIDE
THU NIGHT AND FRI AS WEAK FRONT STALLS TO THE NORTH AND SFC HIGH
PRESSURE BUILDS OFF THE SE COAST. THE PRESSURE GRADIENT WITH THE
OFFSHORE HIGH WILL SUPPORT A LIGHT TO MODERATE (10-15 KT) S/SW
FLOW THRU MUCH OF THE UPCOMING WEEKEND WITH SEAS MAINLY 3 TO 5 FT.
A BACKDOOR FRONT DROPS THRU THE MARINE AREA LATE SUNDAY NIGHT OR
EARLY MONDAY WITH WINDS SHIFTING N/NE WHILE MAINTAINING MODERATE
SPEEDS AOB 15 KTS.
&&
.CLIMATE...
EXTREMELY WARM AND HUMID WEATHER FOR DECEMBER WILL DOMINATE THE
REMAINDER OF CHRISTMAS WEEK. THE FOLLOWING ARE RECORD HIGH MAX
TEMPS, AS WELL AS RECORD HIGH MIN TEMPS, FOR 12/23 THROUGH 12/25,
WHEN THE WARMEST TEMPS ARE EXPECTED. ALSO INCLUDED ARE THE ALL-
TIME HIGHS FOR DECEMBER.
RECORD HIGH MAX TEMPS FOR 12/23 WEDNESDAY
LOCATION TEMP/YEAR
NEW BERN 79/2013 (KEWN ASOS)
CAPE HATTERAS 75/1990 (KHSE ASOS)
GREENVILLE 79/1967 (COOP NOT KPGV AWOS)
MOREHEAD CITY 74/1990 (COOP NOT KMRH ASOS)
KINSTON 82/2013 (COOP NOT KISO AWOS)
JACKSONVILLE 82/1981 (KNCA AWOS)
RECORD HIGH MIN TEMPS FOR 12/23 WEDNESDAY
LOCATION TEMP/YEAR
NEW BERN 63/1990 (KEWN ASOS)
CAPE HATTERAS 66/1990 (KHSE ASOS)
GREENVILLE 61/1990 (COOP - NOT KPGV AWOS)
MOREHEAD CITY 64/2013 (COOP - NOT KMRH ASOS)
KINSTON 65/2013 (COOP- NOT KISO AWOS)
JACKSONVILLE 63/1956 (KNCA AWOS)
RECORD HIGH MAX TEMPS F0R 12/24 THURSDAY
LOCATION TEMP/YEAR
NEW BERN 76/1964 (KEWN ASOS)
CAPE HATTERAS 72/1990 (KHSE ASOS)
GREENVILLE 73/1988 (COOP NOT KPGV AWOS)
MOREHEAD CITY 72/1990 (COOP NOT KMRH ASOS)
KINSTON 78/2013 (COOP NOT KISO AWOS)
JACKSONVILLE 74/1990 (KNCA AWOS)
RECORD HIGH MIN TEMPS FOR 12/24 THURSDAY
LOCATION TEMP/YEAR
NEW BERN 55/2014 (KEWN ASOS)
CAPE HATTERAS 62/1986 (KHSE ASOS)
GREENVILLE 56/1956 (COOP - NOT KPGV AWOS)
MOREHEAD CITY 60/1956 (COOP - NOT KMRH ASOS)
KINSTON 63/1990 (COOP- NOT KISO AWOS)
JACKSONVILLE 54/2014 (KNCA AWOS)
RECORD HIGH MAX TEMPS FOR 12/25 FRIDAY
LOCATION TEMP/YEAR
NEW BERN 78/1955 (KEWN ASOS)
CAPE HATTERAS 73/1964 (KHSE ASOS)
GREENVILLE 77/1964 (COOP NOT KPGV AWOS)
MOREHEAD CITY 74/1974 (COOP NOT KMRH ASOS)
KINSTON 78/1932 (COOP NOT KISO AWOS)
JACKSONVILLE 76/1974 (KNCA AWOS)
RECORD HIGH MIN TEMPS FOR 12/25 FRIDAY
LOCATION TEMP/YEAR
NEW BERN 63/1964 (KEWN ASOS)
CAPE HATTERAS 61/1964 (KHSE ASOS)
GREENVILLE 59/1964 (COOP - NOT KPGV AWOS)
MOREHEAD CITY 60/2008 (COOP - NOT KMRH ASOS)
KINSTON 61/1932 (COOP- NOT KISO AWOS)
JACKSONVILLE 61/1987 (KNCA AWOS)
**ALL-TIME RECORD HIGH TEMPS FOR DECEMBER**
LOCATION TEMP/YEAR
NEW BERN 83/1971 (KEWN ASOS)
CAPE HATTERAS 78/1991 (KHSE ASOS)
GREENVILLE 82/1998 (COOP - NOT KPGV AWOS)
MOREHEAD CITY 79/1998 (COOP - NOT KMRH ASOS)
KINSTON 87/1918 (COOP - NOT KISO AWOS)
JACKSONVILLE 82/1998 (KNCA AWOS)
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL NOON EST FRIDAY FOR AMZ152-154-156-
158.
SMALL CRAFT ADVISORY UNTIL 3 AM EST FRIDAY FOR AMZ150.
&&
$$
SYNOPSIS...SK
NEAR TERM...SK/DAG
SHORT TERM...SK
LONG TERM...RF/BTC
AVIATION...RF/BTC/BM
MARINE...RF/BTC/SK/DAG
CLIMATE...MHX
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
206 PM EST WED DEC 23 2015
.SYNOPSIS...
NEAR RECORD WARMTH FOR MOST OF THE UPCOMING WEEK DESPITE SOME
FAIRLY CLOUDY CONDITIONS. HIGH CHANCE FOR SHOWERS AND ISOLATED
THUNDERSTORMS TODAY...WITH COVERAGE BECOMING MORE ISOLATED DURING
THURSDAY. DRY MID LEVEL AIR SHOULD SHUT DOWN SHOWER ACTIVITY
FRIDAY AND OVER THE WEEKEND AS HIGH PRESSURE OFF THE SOUTHEAST
COAST CONTINUES TO RIDGE ACROSS THE AREA.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 2 PM WEDNESDAY...PATTERN WILL REMAIN UNCHANGED THROUGH THE
END OF THE PERIOD. BERMUDA HIGH REMAINS OFF THE COAST WITH SOUTH
TO SOUTHEAST LOW LEVEL FLOW CONTINUING TO ADVECT WARM MOIST AIR
INTO THE REGION. ALOFT THE BROAD 5H TROUGH OVER MUCH OF THE CONUS
WILL CONTINUE PUMPING GULF AND PACIFIC MOISTURE OVER THE SOUTHEAST
STATES. AS SUCH PWATS WILL APPROACH 2 INCHES THIS EVENING AND
OVERNIGHT...LEVELS THAT HAVE NOT BEEN PREVIOUSLY OBSERVED IN LATE
DEC. ALL OF THIS MOISTURE WILL INTERACT WITH A SERIES OF WEAK
SHORTWAVES MOVING NORTHEAST FROM THE GULF OF MEXICO THIS EVENING
AND OVERNIGHT. A FEW OF THESE WAVES ARE STRONG ENOUGH TO BE SEEN
ON WATER VAPOR BUT MOST ARE TOO WEAK. IN ADDITION TO THE
SHORTWAVES THERE WILL BE SOME DYNAMICS PROVIDED BY A WEAK 200-300
MB JET. ALTHOUGH IT IS WEAK THIS WILL AT LEAST CONTRIBUTE SOME
ADDITIONAL UPWARD MOTION. THE LACK OF WIDESPREAD/LARGE SCALE
FORCING AND THE MORE CONVECTIVE NATURE OF THE ENVIRONMENT POINTS
TO A PRECIP EVENT WHERE MOST AREAS RECEIVE MEASURABLE RAINFALL
BUT NOT AT THE SAME TIME. WHAT LITTLE SURFACE AND MID LEVEL
INSTABILITY WAS PRESENT TODAY WILL BE LESSENED OVERNIGHT AND THINK
THUNDER CHANCES WILL DIMINISH AS THE AFTERNOON COMES TO AN END.
TEMPERATURES WILL CONTINUE TO BE THE BIGGEST STORY OF THE PERIOD
WITH OVERNIGHT LOWS RUNNING AROUND 10 DEGREES ABOVE NORMAL HIGHS
FOR LATE DEC AND AROUND 30 DEGREES ABOVE LOW TEMPERATURES TYPICAL
FOR THIS TIME OF YEAR...ROUGHLY MID TO UPPER 30S.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 3 AM WEDNESDAY...PATTERN CONSISTENCY MORE TYPICAL OF THE WARM
SEASON IN PLACE THROUGH THE PERIOD WITH UPPER RIDGE AND BERMUDA HIGH-
LIKE SURFACE LOCKING INTO PLACE. NO SURPRISE THEN THAT THE
ATMOSPHERE WILL BE PRIMED WITH BOTH COPIOUS WARMTH AND MOISTURE. THE
WARMTH WILL MANIFEST ITSELF AS, WELL, WARMTH. NEAR RECORD VALUES, IN
FACT. THE MOISTURE WILL MOSTLY TAKE FORM OF FAIRLY WIDESPREAD CLOUD
COVER BUT ALSO SOME VERY LOW RAIN CHANCES. THESE LOW RAIN CHANCES
WILL BE FOCUSED ALONG WESTERN ZONES ON THURSDAY AS A WEAK VORT
STREAKS BY COINCIDING WITH A RIBBON OF THE DEEPEST MOISTURE. (THE
OFFSHORE QPF POSSIBLY AFFECTING THE COAST DEPICTED ON THE WRF SEEMS
IMPLAUSIBLE GIVEN THE WARM AIR BEING STABILIZED BY THE CHILLY SSTS).
IT MAY THEN SHIFT TO NORTHERN AND WESTERN ZONES AS A COLD FRONT
BACKDOORS ITS WAY TO THE NC/VA BORDER. OVERALL THOUGH FEEL THAT
FRIDAY MOSTLY RAIN-FREE AS THE RIDGE ALOFT BUILDS WESTWARD PUMPING
HEIGHT RISES INTO THE REGION SUPPRESSING WHAT MAY ALSO BE AN ATTEMPT
AT SEA BREEZE AND WEST WALL CONVECTION SHOWN IN SOME MODELS.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 3 AM WEDNESDAY... MODERATELY HIGHLY AMPLIFIED PATTERN IN PLACE
FOR THE ENTIRE PERIOD. STALWART RIDGE ALOFT HOLDS JUST EAST OF THE
BAHAMAS WHILE CUTOFF UPPER LOW EJECTS FROM THE SOUTHWESTERN U.S.
INTO THE OHIO VALLEY SATURDAY THROUGH MONDAY. TEMPERATURES WILL
CONTINUE THEIR IMPRESSIVE DEVIATIONS FROM CLIMATOLOGY WITH DAYTIME
HIGHS NEARLY 20 DEGREES ABOVE NORMAL AND NIGHTTIME DEVIATIONS OFTEN
EVEN LARGER AS CLOUD COVER LINGERS BENEATH THE SUBSIDENCE INVERSION
BORNE OF THE UPPER RIDGE. RAIN CHANCES ARE BOTH TOUGH TO RULE OUT
WITH SO MUCH LOW LEVEL MOISTURE BUT ALSO HARD TO GET EXCITED ABOUT
DUE TO THE UPPER RIDGE. THE EXCEPTION MAY BE MONDAY WHEN THE RIDGE
GETS BEAT DOWN SUFFICIENTLY FOR SOME HEIGHT FALLS LOCALLY. THEN
AGAIN, THIS USUALLY OCCURS MORE SLOWLY THAN PORTRAYED IN GUIDANCE.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 18Z...MOST OF THE PRECIP HAS DIED DOWN WITH A FEW EXCEPTIONS.
CEILINGS ARE LIKELY TO BE ALL OVER THE PLACE THIS AFTERNOON...EVENTUALLY
BECOMING ALL IFR SOMETIME TONIGHT. THE HRRR MODEL BRINGS CONVECTION
BACK INTO THE WESTERN TERMINALS THIS EVENING...HOWEVER THINK IT WILL
BE MORE OF A STABLE RAIN OR EVEN DRIZZLE AS WE HEAD THROUGH THE
OVERNIGHT HOURS. MODELS ARE HINTING AT SOME LIFR FOG AND THIS SEEMS
REASONABLE. CLOUD COVER AND THE STRONG SOUTHERLY GRADIENT MAY BE
A HINDERANCE. SOME RAIN ON THURSDAY HOWEVER COVERAGE WILL BE LESS
THAN TODAY.
EXTENDED OUTLOOK...POSSIBLE MVFR TO IFR CONDITIONS IN PCPN AND LOW
CEILINGS FROM THROUGH THURSDAY...OTHERWISE EXPECT VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 2 PM WEDNESDAY...SOUTHERLY FLOW WILL CONTINUE AROUND WEST
SIDE OF THE BERMUDA HIGH THIS AFTERNOON AND OVERNIGHT. COMBINATION
OF SURFACE PRESSURE GRADIENT AND LOW LEVEL JET WILL KEEP SPEEDS
IN THE 15 TO 20 KT RANGE THROUGH THE END OF THE PERIOD. THE
PROLONGED DURATION OF SOUTHERLY FLOW IN CONJUNCTION WITH THE
ELEVATED WIND SPEEDS WILL MAINTAIN SEAS OF 4 TO 7 FT THROUGH THE
END OF THE PERIOD. AS SUCH WILL MAINTAIN THE SCA FOR ALL WATERS.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 3 AM WEDNESDAY... PERIOD INITIALIZES WITH A SMALL CRAFT
ADVISORY IN A MODERATELY PINCHED SOUTHWESTERLY GRADIENT FLOW WITH
SOME EMBEDDED ENERGY. A SLIGHT WESTWARD EXTENSION OF A RIDGE AXIS
INTO GA/FL ON THE PART OF THE OFFSHORE HIGH LEADS TO A SLIGHT
WEAKENING OF THE GRADIENT LATER THURSDAY INTO THURSDAY NIGHT AND
FRIDAY. WIND REMAINS MOSTLY SOUTHWESTERLY ON FRIDAY BUT IN A
LIGHTENED STATE. THE RIDGE AXIS SHOULD ALSO DISRUPT THE SWELL
ENERGY A BIT TO HELP FURTHER REDUCE DOMINANT WAVE HEIGHT.
LONG TERM /SATURDAY THROUGH SUNDAY/...
AS OF 3 AM WEDNESDAY... MUCH MORE OF A WARM SEASON PATTERN IN
PLACE WITH A WEST ATLANTIC HIGH DOMINATING AND A COMPLETE LACK OF
ANY FRONTS. THE MAIN DIFFERENCE PATTERN-WISE WILL BE THAT THE HIGH
WILL BE WEAKER AND FURTHER WEST THAN WHAT IS NORMALLY OBSERVED IN
THE WARM SEASON. AS SUCH WIND SPEEDS MAY WELL BE CAPPED AT 10KT AS
THE DIRECTION REMAINS SOUTH TO SOUTHWESTERLY. SEAS WILL AVERAGE 2
TO 3 AND OCCASIONALLY (WELL OFFSHORE) 4 FT.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL NOON EST THURSDAY FOR AMZ250-252-
254-256-270-274.
&&
$$
NEAR TERM...III
SHORT TERM...MBB
LONG TERM...MBB
AVIATION...DL
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
127 PM EST WED DEC 23 2015
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE OFFSHORE THROUGH THE WEEKEND. A WEAK
COLD FRONT WILL APPROACH FROM THE NORTH THURSDAY NIGHT THEN STALL
NEAR THE VIRGINIA BORDER FRIDAY. THE FRONT WILL LIFT BACK NORTH
OVER THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 1020 AM WEDNESDAY...LATE MORNING UPDATE FOR ONLY MINOR
TWEAKS IN THE NEAR TERM. CONVECTION HAS SHOWN POTENTIAL TO BECOME
SEVERE FOR WESTERN ZONES (DUPLIN/ONSLOW/GREENE/LENOIR COUNTIES)
WHERE SPC MESOANALYSES INDICATE BETTER INSTABILITY. IR SATELLITE
IMAGERY INDICATED WARMING CLOUD TOPS AS THE EARLIER CONVECTION
SHIFTS NORTH ACROSS THE HWY 64 CORRIDOR. A PERIOD OF HEAVY RAIN
AND POSSIBLY GUSTY WINDS WILL STILL BE POSSIBLE INTO EARLY
AFTERNOON WITH SHOWER COVERAGE INCREASING FROM THE SOUTH AND WEST.
THE SYNOPTIC PATTERN PRESENTS AN UPPER TROUGH MOVING INTO THE
PLAINS WITH RIDGING OVER THE ATLANTIC, BRINGING DEEP SW FLOW
ACROSS THE EASTERN CONUS THAT IS TAPPING INTO TROPICAL PACIFIC
MOISTURE BRINGING PWATS AROUND 1.75 INCHES WHICH IS AT OR ABOVE
CLIMATOLOGICAL MAXIMUM FOR LATE DECEMBER. SFC HIGH PRES REMAINS
CENTERED OFFSHORE WITH A COASTAL TROUGH JUST SOUTH OF THE REGION
PROGGED TO LIFT ACROSS THE REGION TODAY. THIS PATTERN WILL
CONTINUE TO BRING PERIODS OF SHOWERS ACROSS THE REGION TODAY WHICH
ARE BEING ENHANCED BY WEAK EMBEDDED SHORTWAVES MOVING THROUGH THE
FLOW ALOFT. COULD SEE A FEW STRONGER STORMS DEVELOP THROUGH THE
AFTERNOON HOURS AS THE AIRMASS DESTABILIZES IN THE PRESENCE OF
STRONG LOW LEVEL SHEAR. HRRR IS FORECASTING MLCAPE AROUND
1000-1500J/KG AND LI`S AROUND -4C WITH 40-50 KT 0-6KM SHEAR AND
0-1KM HELICITY AROUND 200-300 M2/S2 THIS AFTERNOON WITH HIGHEST
VALUES WEST OF HIGHWAY 17. SPC HAS MOST OF THE REGION OUTLOOKED
FOR A MARGINAL RISK OF SEVERE THUNDERSTORMS WITH DAMAGING WIND
GUSTS AND AN ISOLATED TORNADO THE PRIMARY THREAT. PERIODS OF HEAVY
RAINFALL WITH LOCALIZED FLOODING OF POOR DRAINAGE AND LOW LYING
AREA WILL ALSO BE POSSIBLE. EXPECT GUSTY SLY WINDS TO DEVELOP LATE
MORNING THROUGH THE AFTERNOON IN THE WAKE OF THE TROUGH LIFTING
ACROSS THE REGION WHICH COULD BRING GUSTS AROUND 20-30 MPH. TEMPS
WILL BE ALMOST 20 DEGREES ABOVE NORMAL WITH HIGHS EXPECTED IN THE
MID 70S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/...
AS OF 3 AM WEDNESDAY....LITTLE CHANGE IN THE PATTERN TONIGHT WITH
MOIST SW FLOW CONTINUING. A FEW STRONGER STORMS WILL BE POSSIBLE
EARLY IN THE EVENING BUT GENERALLY EXPECT A DECREASE IN COVERAGE
THROUGH THE OVERNIGHT AS SHORTWAVE ENERGY LIFTS NORTH OF THE
REGION AND THE UPPER RIDGE OVER THE WESTERN ATLANTIC BEGINS TO
BUILDS WEST SOME. WILL CONTINUE A DECREASING TREND IN POPS THROUGH
THE OVERNIGHT. MODERATE SLY WINDS WILL BRING VERY MILD OVERNIGHT
TEMPS IN THE UPPER 60S TO 70...WHICH IS ABOUT 30-35 DEGREES ABOVE
NORMAL AND WILL LIKELY BREAK RECORD HIGH MINIMUM TEMPERATURES FOR
THE DAY...SEE CLIMATE SECTION BELOW.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
AS OF 220 AM WED...BIG STORY WILL BE RECORD BREAKING WARM TEMPS
THROUGH MUCH OF THE PERIOD AS STRONG UPPER RIDGE OVER THE ATLANTIC
BUILDS WEST TOWARD THE COAST INTO THE WEEKEND.
THURSDAY THROUGH CHRISTMAS DAY...COVERAGE OF PRECIPITATION WILL
DROP A BIT FOR THURSDAY AND FRIDAY AS UPR RDG GRAD BUILDS W. FCST
SOUNDINGS FOR THU SHOW SBCAPE VALUES POSSIBLY GREATER THAN 1500
J/KG AND LI`S IN THE -3 TO -5 RANGE DURING THE AFTERNOON ALONG
WITH DECENT SHEAR...HOWEVER LACK OF FORCING MAY LIMIT TSRA
POTENTIAL. A FEW STRONG TO POSS SEVERE STORMS CAN NOT BE RULED
OUT GIVEN THE VERY HIGH INSTAB FOR LATE DEC. LOW LVL
THICKNESS/850 TEMPS PEAK THU AFTN WITH SOME HIGHS TEMPS IN THE
LOWER 80S POSS WHICH WILL LIKELY BREAK NUMEROUS RECORDS AND POSS
SET ALL TIME DEC RECORDS. ON FRI UPR RDG BUILDS CLOSER WHICH WILL
ACT TO SUPPRESS CONVECTION AND WITH MORE SUN TEMPS WILL AGAIN BE
VERY WARM REACHING AROUND 80 AGAIN WARMER SPOTS.
SATURDAY THROUGH SUNDAY...STRONG UPPER LEVEL RIDGE HOLDS ACROSS
THE SOUTHEASTERN UNITED STATES THROUGH THE WEEKEND AS LOW
PRESSURE MOVES FROM THE MISSISSIPPI VALLEY INTO THE GREAT LAKES
REGION. THIS WILL KEEP UNSEASONABLY WARM TEMPERATURES IN PLACE
WITH DAYTIME HIGHS WELL INTO THE 70S SATURDAY AND SUNDAY WITH LOWS
IN THE 60S. THERE WILL BE ONLY A SMALL CHANCE OF SHOWERS EACH DAY
GIVEN THE CONTINUED RATHER MOIST AIRMASS WITH FORECAST
PRECIPITABLE WATER VALUES AOA 1.50 INCHES.
MONDAY THROUGH TUESDAY...UPR RDG WILL BEGIN TO SHIFT BACK E WITH
MDLS SHOWING BACKDOOR FRONT DROPPING INTO THE REGION MON THEN
LIFTING BACK N TUE AHEAD OF STRONGER APPROACHING FRONT. CONT PREV
FCST OF CHC POPS EARLY NEXT WEEK WITH STILL VERY MILD TEMPS IN THE
60S TO LOWER 70S...POSS SOME MID 70S TUE.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
SHORT TERM /THROUGH TONIGHT/...
AS OF 1 PM WEDNESDAY...HIGH CONFIDENCE OF MVFR CONDITIONS WILL
PERSIST MOST OF THE TAF PERIOD. WITH A MOIST SW FLOW...PERIODS OF
SHOWERS WILL CONTINUE ACROSS THE AREA. SOME STORMS COULD BE
STRONG TO MARGINALLY SEVERE THIS AFTERNOON IF INSTABILITY CAN BE
REALIZED WITH STRONG SHEAR IN PLACE AND SHORTWAVE ENERGY MOVING
ACROSS THE REGION. THESE SHOWERS/THUNDERSTORMS ARE EXPECT TO BRIEFLY
REDUCE VSBYS/CEILINGS. SOUTHERLY WINDS 10-15 KTS WITH GUSTS 20 TO
25 KNOTS REDUCING DOWN TO AROUND 10 KTS OVERNIGHT. FORECASTING
SOUNDING AND GUIDANCE CONTINUES TO SHOW MVFR CEILINGS FOR TONIGHT
AND REDUCING DOWN TO IFR CEILINGS AROUND 7/8Z. CEILINGS ARE
EXPECTED TO INCREASE BACK TO MVFR THURS MORNING WITH WIND GUST
INCREASING BACK AGAIN.
LONG TERM /THU THROUGH SATURDAY/...
AS OF 220 AM WED...COVERAGE OF SHRA/TSRA WILL BE LESS THURSDAY
THROUGH SAT BUT WITH LOW LEVELS REMAINING VERY MOIST BOUTS OF SUB
VFR STRATUS AND FOG WILL BE LIKELY LATE NIGHT/EARLY MORN. MAINLY
VFR LATE MORN THRU EVENING HOURS WITH ONLY SMALL CHC OF SHRA/TSRA
CROSSING. ISOLATED STRONG THUNDERSTORMS WILL BE POSS THU.
&&
.MARINE...
SHORT TERM /THROUGH TONIGHT/
AS OF 1025 AM WEDNESDAY...LATEST SURFACE AND BUOY DATA INDICATE SE
TO SSW WINDS ACROSS THE EASTERN NC WATERS 5-15 KT WITH GUSTS NEAR
20 KT FOR THE OUTER BUOYS 41025/41064. THE SURFACE RIDGE REMAINS
CENTERED OFF THE SOUTHEAST COAST THROUGH THE SHORT TERM. A COASTAL
TROUGH JUST SOUTH OF THE WATERS IS PROGGED TO LIFT ACROSS THE
REGION THIS MORNING. SE WINDS AROUND 5-15 KT WILL BECOME SLY AND
INCREASE TO 15-25 KT WITH HIGHER GUSTS AFTER THE TROUGH LIFTS
ACROSS THE REGION AND CONTINUE THROUGH MUCH OF THE OVERNIGHT. SEAS
CURRENTLY AROUND 3-6 FT WILL BUILD IN RESPONSE TO THE STRONGER SLY
FLOW THROUGH THE DAY...PEAKING AROUND 6-10 FT TONIGHT. STRONGEST
WINDS/SEAS WILL OCCUR OVER THE COASTAL WATERS AND WILL CONTINUE
THE SCA. THE SOUNDS AND RIVERS EXPECTED TO REMAIN JUST BELOW
ADVISORY CRITERIA BUT MAY BE CLOSE ACROSS THE PAMLICO SOUND,
ESPECIALLY IN GUSTS.
LONG TERM /THU THROUGH SATURDAY/...
AS OF 220 AM WED...SSW WINDS 15 TO 25 KTS WILL CONT THU BETWEEN
HIGH PRESSURE NEAR BERMUDA AND LOW PRESSURE LIFTING NORTHEAST OF
THE GREAT LAKES. SW WINDS WILL GRAD SUBSIDE THU NIGHT AND FRI AS
WEAK FRONT STALLS TO THE NORTH. THE FRONT WILL LIFT BACK N SAT
WITH CONT LIGHT S TO SW FLOW. SEAS WILL REMAIN ELEVATED THU AND
THU NIGH WITH SCA CONT COASTAL WATERS. SEAS WILL PEAK AT AROUND 8
FT OUTER SRN/CNTRL WATERS THU. SEAS WILL SUBSIDE THU NIGHT AND
FRI WITH SCA ENDING NRN WATERS LATE THU NIGHT AND REST OF WATERS
BY MID DAY FRI. SEAS WILL CONT IN THE 3 TO 5 FT RANGE THRU SAT.
&&
.CLIMATE...
EXTREMELY WARM AND HUMID WEATHER FOR DECEMBER WILL DOMINATE THE
REMAINDER OF CHRISTMAS WEEK. THE FOLLOWING ARE RECORD HIGH MAX
TEMPS, AS WELL AS RECORD HIGH MIN TEMPS, FOR 12/23 THROUGH 12/25,
WHEN THE WARMEST TEMPS ARE EXPECTED. ALSO INCLUDED ARE THE ALL-
TIME HIGHS FOR DECEMBER.
RECORD HIGH MAX TEMPS FOR 12/23 WEDNESDAY
LOCATION TEMP/YEAR
NEW BERN 79/2013 (KEWN ASOS)
CAPE HATTERAS 75/1990 (KHSE ASOS)
GREENVILLE 79/1967 (COOP NOT KPGV AWOS)
MOREHEAD CITY 74/1990 (COOP NOT KMRH ASOS)
KINSTON 82/2013 (COOP NOT KISO AWOS)
JACKSONVILLE 82/1981 (KNCA AWOS)
RECORD HIGH MIN TEMPS FOR 12/23 WEDNESDAY
LOCATION TEMP/YEAR
NEW BERN 63/1990 (KEWN ASOS)
CAPE HATTERAS 66/1990 (KHSE ASOS)
GREENVILLE 61/1990 (COOP - NOT KPGV AWOS)
MOREHEAD CITY 64/2013 (COOP - NOT KMRH ASOS)
KINSTON 65/2013 (COOP- NOT KISO AWOS)
JACKSONVILLE 63/1956 (KNCA AWOS)
RECORD HIGH MAX TEMPS F0R 12/24 THURSDAY
LOCATION TEMP/YEAR
NEW BERN 76/1964 (KEWN ASOS)
CAPE HATTERAS 72/1990 (KHSE ASOS)
GREENVILLE 73/1988 (COOP NOT KPGV AWOS)
MOREHEAD CITY 72/1990 (COOP NOT KMRH ASOS)
KINSTON 78/2013 (COOP NOT KISO AWOS)
JACKSONVILLE 74/1990 (KNCA AWOS)
RECORD HIGH MIN TEMPS FOR 12/24 THURSDAY
LOCATION TEMP/YEAR
NEW BERN 55/2014 (KEWN ASOS)
CAPE HATTERAS 62/1986 (KHSE ASOS)
GREENVILLE 56/1956 (COOP - NOT KPGV AWOS)
MOREHEAD CITY 60/1956 (COOP - NOT KMRH ASOS)
KINSTON 63/1990 (COOP- NOT KISO AWOS)
JACKSONVILLE 54/2014 (KNCA AWOS)
RECORD HIGH MAX TEMPS FOR 12/25 FRIDAY
LOCATION TEMP/YEAR
NEW BERN 78/1955 (KEWN ASOS)
CAPE HATTERAS 73/1964 (KHSE ASOS)
GREENVILLE 77/1964 (COOP NOT KPGV AWOS)
MOREHEAD CITY 74/1974 (COOP NOT KMRH ASOS)
KINSTON 78/1932 (COOP NOT KISO AWOS)
JACKSONVILLE 76/1974 (KNCA AWOS)
RECORD HIGH MIN TEMPS FOR 12/25 FRIDAY
LOCATION TEMP/YEAR
NEW BERN 63/1964 (KEWN ASOS)
CAPE HATTERAS 61/1964 (KHSE ASOS)
GREENVILLE 59/1964 (COOP - NOT KPGV AWOS)
MOREHEAD CITY 60/2008 (COOP - NOT KMRH ASOS)
KINSTON 61/1932 (COOP- NOT KISO AWOS)
JACKSONVILLE 61/1987 (KNCA AWOS)
**ALL-TIME RECORD HIGH TEMPS FOR DECEMBER**
LOCATION TEMP/YEAR
NEW BERN 83/1971 (KEWN ASOS)
CAPE HATTERAS 78/1991 (KHSE ASOS)
GREENVILLE 82/1998 (COOP - NOT KPGV AWOS)
MOREHEAD CITY 79/1998 (COOP - NOT KMRH ASOS)
KINSTON 87/1918 (COOP - NOT KISO AWOS)
JACKSONVILLE 82/1998 (KNCA AWOS)
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL NOON EST FRIDAY FOR AMZ152-154-156-
158.
SMALL CRAFT ADVISORY UNTIL 3 AM EST FRIDAY FOR AMZ150.
&&
$$
SYNOPSIS...SK
NEAR TERM...SK/DAG
SHORT TERM...SK
LONG TERM...RF/DAG
AVIATION...RF/BM
MARINE...RF/SK/DAG
CLIMATE...MHX
AREA FORECAST DISCUSSION
NWS RALEIGH NC
115 PM EST WED DEC 23 2015
.SYNOPSIS...A WEDGE FRONT WILL REMAIN QUASI-STATIONARY OVER THE
PIEDMONT EARLY TODAY...THEN BE OVERTAKEN BY A MARITIME WARM FRONT
THAT WILL SURGE ACROSS THE CAROLINAS AND SOUTHEASTERN VIRGINIA THIS
AFTERNOON. ANOMALOUSLY STRONG SUB-TROPICAL HIGH PRESSURE OVER THE
WEST-CENTRAL ATLANTIC OCEAN WILL THEN DIRECT UNSEASONABLY WARM AND
MOIST SOUTHERLY FLOW THROUGHOUT THE SOUTHEASTERN UNITED STATES
THROUGH CHRISTMAS.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1040 AM WEDNESDAY...
...FLASH FLOOD WATCH CONTINUES ACROSS THE WESTERN PIEDMONT...
DEEP MOIST SOUTHERLY FLOW...CHARACTERIZED BY NEARLY CLIMATOLOGICAL MAX
PW OF 1.8 INCHES AND 850MB DEWPOINTS OF 14-15C...CONTINUES AROUND THE
ANOMALOUSLY STRONG RIDGE OVER THE WESTERN ATLANTIC. A WEDGE FRONT
IS HOLDING FROM CENTRAL VA THROUGH THE NC WESTERN PIEDMONT AND INTO
UPSTATE SC...WHILE A COASTAL WARM FRONT IS BEGINNING TO SURGE INLAND
AS UPPER 60S DEWPOINTS HAVE REACHED THE I-95 CORRIDOR. IN THE WEDGE
AIRMASS...DENSE FOG WILL CONTINUE...PERIODICALLY DISPERSED BY
SHOWERS SPREADING NORTH THROUGH THE PIEDMONT. NEARLY ALL GUIDANCE
SHOWS THE WEDGE FRONT ERODING AND 60S DEWPOINTS ALL THE WAY THROUGH
FORSYTH CO THIS AFTERNOON. MEANWHILE...THE WARM FRONT AND LEADING
EDGE OF WEAKLY UNSTABLE AIR...WITH MLCAPE POTENTIALLY EXCEEDING 500
J/KG...WILL ALSO CONTINUE INLAND...ALTHOUGH WITH RAIN ALMOST
CONTINUOUS IN THE PIEDMONT IT`S STILL A LITTLE UNCLEAR HOW FAR
INLAND THE WARM SECTOR WILL MIX. DEEP LAYER SHEAR WILL BE 45-
50KT...WHICH WILL SUPPORT A SEVERE THREAT OVER THE COASTAL PLAIN
WHERE THE SHEAR/INSTABILITY PARAMETER SPACE IS BEST. LOW-LEVEL IS
ENHANCED BY A 40KT SOUTHWESTERLY LLJ AND SOUTHEASTERLY SURFACE
WIND...ESPECIALLY IN THE VICINITY OF THE WARM FRONT...AND SHERBE
VALUES ARE PROGGED AROUND 1 THROUGH THE PIEDMONT THIS AFTERNOON.
GOING AGAINST THE SEVERE THREAT IS A GENERAL LACK OF A FOCUS...AS A
NOTABLE MCV OVER NORTHERN GA SHOULD MOVE MORE ALONG THE
MOUNTAINS...AND RAP SOUNDINGS MAINTAIN A SMALL CAPPING INVERSION
THROUGH THE AFTERNOON THAT WOULD LIMIT THE ALREADY WEAK MUCAPE.
HOWEVER...THE SPC MARGINAL RISK STILL LOOKS WARRANTED GIVEN THE
ANOMALOUSLY HIGH PW AND UNUSUAL AIRMASS FOR LATE DECEMBER.
THE FLOODING THREAT...WHILE IT HASN`T MATERIALIZED IN THE
WEST...STILL EXISTS GIVEN THE AFOREMENTIONED MCV MOVING UP FROM GA.
THE HRRR SHOWS A LARGE AREA OF PRECIP...INCREASINGLY CONVECTIVE
LOOKING...OVER THE WESTERN PIEDMONT THIS AFTERNOON. IN ADDITION...A
FEW RIVERS...INCLUDING THE ROCKY RIVER AND HAW RIVER...ARE EITHER
EXPERIENCING MINOR FLOODING OR FORECAST TO FLOOD. SO WE WILL
CONTINUE THE FLASH FLOOD WATCH FOR NOW.
TEMPS WILL SLOWLY RISE THROUGH THE 60S IN THE PIEDMONT AND INTO THE
70S IN THE COASTAL PLAIN...WITH MAX VALUES IN THE 65-75 RANGE THIS
AFTERNOON. -22
SHOWERS WILL CONTINUE TO BE A POSSIBILITY TONIGHT...AND LOW
TEMPERATURES WILL STRUGGLE TO DROP OUT OF THE 70S AT MOST
LOCATIONS...AGAIN HAVING A GOOD CHANCE OF MATCHING THE ALL-TIME
WARMEST DECEMBER MINIMUM TEMPERATURE ON RECORD(RDU-69...FAY-69...GSO-
65).
&&
.SHORT TERM /THURSDAY AND THURSDAY NIGHT/...
AS OF 355 AM WEDNESDAY...
ON THE WESTERN PERIPHERY OF ANOMALOUSLY STRONG SUB-TROPICAL RIDGING
CENTERED OVER THE WEST-CENTRAL ATLANTIC...SHORTWAVE RIDGING AND
ASSOCIATED HEIGHT RISES ALOFT WILL BUILD BEHIND THE MAIN SHORTWAVE
TROUGH LIFTING INTO EASTERN CANADA. WITH RIDGING ALOFT AND AN
ASSOCIATED PROBABLE CAPPING INVERSION DEPICTED ON NAM BUFR
SOUNDINGS...THE DAY WILL LIKELY BE A DRY ONE...THOUGH DIURNAL
HEATING OF THE UNSEASONABLY WARM (70S TO AROUND 80 IN IN THE I-95
CORRIDOR) AND HUMID BOUNDARY LAYER MAY ALLOW FOR SOME CU TO BYPASS
THE CAP AND GROW INTO ISOLATED SHOWERS/STORMS. IN ADDITION...AN
UPSTREAM QLCS...IN A REGION OF RESIDUALLY STRONG H85 MOISTURE
TRANSPORT DIRECTED INTO THE TN VALLEY...MAY SUPPORT THE EASTWARD
PROGRESSION OF A WEAKENING LONE OF SHOWERS AND STORMS TO CROSS THE
APPALACHIANS AND DRIFT INTO WESTERN NC...INCLUDING THE WESTERN
PIEDMONT EARLY THU NIGHT. INCREASING CINH WITH NOCTURNAL "COOLING"
INTO THE 60S FAVORS A DRY NIGHT OTHERWISE AND ELSEWHERE.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 410 AM WEDNESDAY...
THE STRONG SUB-TROPICAL RIDGE...WITH ANOMALOUSLY HIGH HEIGHTS AND
PRECIPITABLE WATER VALUES BETWEEN 200-300 PERCENT OF NORMAL FROM THE
SOUTHEASTERN UNITED STATES TO EAST-CENTRAL CANADA...WILL MAINTAIN A
VERY MILD-WARM REGIME ACROSS THE SOUTHEASTERN STATES THROUGHOUT THE
PERIOD...AND A WET ONE PRIMARILY NORTHWEST OF CENTRAL NC...AT LEAST
UNTIL LATE IN THE PERIOD. THE MAIN FORECAST UNCERTAINTY REMAINS THE
POSITIONING OF A WAVY FRONTAL ZONE FORECAST TO MEANDER ACROSS THE
MIDDLE ATLANTIC STATES...AND CONSEQUENTLY HOW MUCH SUPPRESSION OF
THE WARMTH OCCURS EAST OF THE APPALACHIANS...DICTATED BY A BATTLE
BETWEEN THE SUB-TROPICAL RIDGE AND CONFLUENT SPLIT FLOW
ALOFT/UNDERLYING POLAR HIGHS FORECAST TO DEVELOP ACROSS THE GREAT
LAKES AND NEW ENGLAND BY THIS WEEKEND.
THE TIMING OF POTENTIAL COLD FRONTAL SURGES INTO NC...IF THEY
OCCUR...ARE FAVORED LATE FRI NIGHT-SAT...AND AGAIN SUN NIGHT-
MON...WITH THE FORMER APPEARING INCREASINGLY UNLIKELY TO AFFECT
CENTRAL NC. OTHERWISE UNSEASONABLY MILD-WARM AND HUMID CONDITIONS IN
DEEP SOUTHERLY FLOW AROUND THE SUB-TROPICAL RIDGE WILL PREVAIL. THE
PRIMARY BRANCH OF THE NORTHERN STREAM WILL BE BLOCKED TO THE NW BY
THE SUB-TROPICAL RIDGING...SO FORCING FOR ASCENT AND ASSOCIATED
PRECIPITATION CHANCES WILL REMAIN LOW (GENERALLY AOB 20 PERCENT) AND
INSTEAD DRIVEN BY LOWER AMPLITUDE SOUTHERN STREAM PERTURBATIONS AND
ASSOCIATED SURGES OF LOW LEVEL THETA-E ADVECTION AND BRIEF EROSION
OF A CAPPING INVERSION FRI-SAT...WITH SAID CAPPING MORE LIKELY TO BE
OVERCOME BY DIURNAL HEATING IN AN AIRMASS MORE CHARACTERISTIC OF
APRIL-MAY THAN LATE DECEMBER.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 115 PM WEDNESDAY...
POOR AVIATION CONDITIONS WILL CONTINUE THROUGH THE TAF PERIOD WITH
MOIST SOUTHERLY FLOW AND NUMEROUS TO WIDESPREAD SHOWERS THROUGH THIS
EVENING. A WARM FRONT PROGRESSING NORTHWEST THROUGH THE AREA WILL
LIFT CEILINGS TO MVFR LEVELS IN THE EAST...MOST LIKELY AT
KFAY/KRWI...WITH LOWER CEILINGS IN THE LIFR/IFR CEILINGS TO HANG ON
AT KGSO/KINT. WINDS WILL GUST TO 20-25KT...MAINLY AT
KRDU/KRWI/KFAY...A FEW STRONG STORMS COULD PRODUCE LOCALLY HIGHER
GUSTS WITH HEAVY RAIN. SHOWERS WILL GENERALLY LESSEN IN COVERAGE
OVERNIGHT...WITH CEILINGS LIKELY TO LOWER TO IFR OR LIFR AGAIN.
SOME GUIDANCE INDICATES FOG...BUT WINDS WILL STAY UP IN THE 8-12KT
RANGE...WHICH SHOULD KEEP VSBYS AT LEAST 3SM. SOME SMALL
IMPROVEMENTS WIN CONDITIONS WILL BE POSSIBLE ON THURSDAY
WITH LESS PRECIP COVERAGE...THOUGH IFR AND MVFR CONDITIONS WILL
CONTINUE TO PREVAIL.
OUTLOOK...WITH DEEP AND MOIST SOUTHWESTERLY FLOW CONTINUING THIS
WEEKEND...PERIODS OF POOR AVIATION CONDITIONS WILL
PERSIST...ESPECIALLY OVERNIGHT.
&&
.CLIMATE...
HERE ARE THE AREA RECORD MAXIMUMS AND HIGH MINIMUMS FOR DECEMBER 24TH
AND 25TH. RECORDS HAVE BEEN KEPT IN THE GREENSBORO AREA SINCE
1903... IN THE RALEIGH AREA SINCE 1887... AND IN THE FAYETTEVILLE
AREA SINCE 1910.
DEC 24: RECORD MAXIMUM HIGH MINIMUM
GREENSBORO 71 (1964) 52 (1904)
RALEIGH 75 (1931) 59 (1891)
FAYETTEVILLE 78 (1931) 66 (1990)
DEC 25: RECORD MAXIMUM HIGH MINIMUM
GREENSBORO 74 (1955) 58 (1932)
RALEIGH 75 (1955) 63 (1932)
FAYETTEVILLE 79 (1932) 68 (1932)
&&
.RAH WATCHES/WARNINGS/ADVISORIES... NONE.
&&
$$
SYNOPSIS...2
NEAR TERM...CBL/22
SHORT TERM...2
LONG TERM...2
AVIATION...22
CLIMATE...HARTFIELD/BLAES
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1151 AM EST WED DEC 23 2015
.SYNOPSIS...
NEAR RECORD WARMTH FOR MOST OF THE UPCOMING WEEK DESPITE SOME
FAIRLY CLOUDY CONDITIONS. HIGH CHANCE FOR SHOWERS AND ISOLATED
THUNDERSTORMS TODAY...WITH COVERAGE BECOMING MORE ISOLATED DURING
THURSDAY. DRY MID LEVEL AIR SHOULD SHUT DOWN SHOWER ACTIVITY
FRIDAY AND OVER THE WEEKEND AS HIGH PRESSURE OFF THE SOUTHEAST
COAST CONTINUES TO RIDGE ACROSS THE AREA.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 AM WEDNESDAY...ACTIVE PATTERN CONTINUES TODAY WITH
BERMUDA HIGH CONTINUING LOW LEVEL SOUTHERLY FLOW AND BROAD 5H
TROUGH AXIS TO THE WEST ENSURING FLOW ALOFT REMAINS SOUTHWEST.
THE RESULT IS DEEP MOISTURE OVER THE SOUTHEAST. PWATS IN FORECAST
SOUNDINGS APPROACH 2 INCHES THIS EVENING AND THE 12Z FLIGHT FROM
CHS REPORTED A PWAT OF 1.86...CLOSE TO 0.30 INCH ABOVE THE
PREVIOUS HIGH FOR THIS DATE. IN ADDITION TO THE ABUNDANT MOISTURE
THERE WILL BE A SERIES OF WEAK SHORTWAVES MOVING THROUGH THE FLOW
ALOFT. GUIDANCE ALSO SHOWS A WEAK JET STREAK IN THE 200-300 MB
LAYER WHICH MAY ENHANCE LIFT LATER THIS AFTERNOON AND EVENING.
IN ADDITION TO THE DYNAMICS THERE IS SOME SURFACE BASED
INSTABILITY. CAPE WILL PEAK AROUND 1500 J/KG BUT INSTABILITY
WITHIN REGIONS FAVORED FOR DEEPER CONVECTION AND LIGHTNING IS
LIMITED. HELD ONTO ISOLATED THUNDER BUT MOST AREAS ARE NOT LIKELY
TO EXPERIENCE ANY. ALTHOUGH A HIGH POP IS WARRANTED TODAY AND
TONIGHT COVERAGE WILL BE LIMITED AT ANY ONE TIME GIVEN THE
CONVECTIVE NATURE OF THE PRECIP. STRONG LOW LEVEL JET IN PLACE
TODAY WITH WINDS OF 30 TO 35 KT AROUND 1K FT. THUS FAR THE STABLE
SURFACE LAYER HAS PREVENTED STRONGER WINDS FROM BEING MIXED DOWN
BUT CANNOT RULE OUT AN ISOLATED STRONG/SEVERE STORM OR TWO IN THE
AFTERNOON. TEMPERATURES CONTINUE TO RUN WELL ABOVE CLIMO WITH
HIGHS IN THE MID 70S EXPECT ACROSS MUCH OF THE AREA.
DISCUSSION FROM 630 THIS MORNING FOLLOWS:
LATEST LOCAL AND MOSAIC RADAR DATA INDICATES PCPN CONTINUES TO
STREAM UP TO THE NNE ACROSS THE CAROLINAS. THIS IS IN RESPONSE TO
A MIDLEVEL S/W TROF LIFTING N TO NE WITHIN STRONG MID- LEVEL SSW
FLOW. THE BEST OR MAIN DYNAMICS FROM THIS S/W TROF STAY WEST OF
THE ILM CWA TODAY...BUT MODELS INDICATE THE TRAILING MID- LEVEL
SHEARED AXIS WILL MAKE ITS WAY TO THE CAROLINA COASTS BY LATE THIS
EVENING. DEEP GULF OF MEXICO AND ATLANTIC MOISTURE WILL CONTINUE
TO PUMP ACROSS THE ILM CWA WITH PROGGED PWS IN THE 1.5 TO 2.00
INCH RANGE. TO PUT IT ALL TOGETHER...THE FA WILL BE UNDER THE
LIKELY TO CATEGORICAL POP THREAT FROM SHOWERS AND EMBEDDED
ISOLATED THUNDERSTORMS TODAY THRU THIS EVENING. AVBL CAPE OF 1K TO
POSSIBLY 1.25K WILL BE LOW ALTHOUGH BETTER THAN YESTERDAY...AND
WITH PROGGED LAPSE RATES REMAINING SUSPECT...HAVE KEPT THE TSTORM
THREAT TO ISOLATED AT BEST FOR NOW.
NO FLOOD WATCHES ARE FORECAST FOR THE ILM CWA. HOWEVER...ANY
TRAINING OF HEAVY SHOWERS OVER AREAS RECEIVING A GOOD DOSE OF
RAINFALL FROM TUESDAY...COULD RESULT IN PONDING OF WATER
ESPECIALLY ACROSS LOW LYING AREAS AND PRONE ROADWAYS. WILL
HIGHLIGHT THIS IN THE HAZARDOUS WEATHER OUTLOOK.
TEMPS WILL CONTINUE TO RUN 15 TO 25+ DEGREES ABOVE NORMAL.
TODAYS HIGHS IN THE MID TO UPPER 70S AND TONIGHTS LOWS IN THE MID
TO UPPER 60S. THIS SOUNDS MORE LIKE A MID FALL OR MID SPRING TEMP
FORECAST. OF NOTE...NORMAL HIGHS ARE IN THE MID TO UPPER 50S AND
NORMAL LOWS ARE IN LOW TO MID 30S.
&&
.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
AS OF 3 AM WEDNESDAY...PATTERN CONSISTENCY MORE TYPICAL OF THE WARM
SEASON IN PLACE THROUGH THE PERIOD WITH UPPER RIDGE AND BERMUDA HIGH-
LIKE SURFACE LOCKING INTO PLACE. NO SURPRISE THEN THAT THE
ATMOSPHERE WILL BE PRIMED WITH BOTH COPIOUS WARMTH AND MOISTURE. THE
WARMTH WILL MANIFEST ITSELF AS, WELL, WARMTH. NEAR RECORD VALUES, IN
FACT. THE MOISTURE WILL MOSTLY TAKE FORM OF FAIRLY WIDESPREAD CLOUD
COVER BUT ALSO SOME VERY LOW RAIN CHANCES. THESE LOW RAIN CHANCES
WILL BE FOCUSED ALONG WESTERN ZONES ON THURSDAY AS A WEAK VORT
STREAKS BY COINCIDING WITH A RIBBON OF THE DEEPEST MOISTURE. (THE
OFFSHORE QPF POSSIBLY AFFECTING THE COAST DEPICTED ON THE WRF SEEMS
IMPLAUSIBLE GIVEN THE WARM AIR BEING STABILIZED BY THE CHILLY SSTS).
IT MAY THEN SHIFT TO NORTHERN AND WESTERN ZONES AS A COLD FRONT
BACKDOORS ITS WAY TO THE NC/VA BORDER. OVERALL THOUGH FEEL THAT
FRIDAY MOSTLY RAIN-FREE AS THE RIDGE ALOFT BUILDS WESTWARD PUMPING
HEIGHT RISES INTO THE REGION SUPPRESSING WHAT MAY ALSO BE AN ATTEMPT
AT SEA BREEZE AND WEST WALL CONVECTION SHOWN IN SOME MODELS.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 3 AM WEDNESDAY... MODERATELY HIGHLY AMPLIFIED PATTERN IN PLACE
FOR THE ENTIRE PERIOD. STALWART RIDGE ALOFT HOLDS JUST EAST OF THE
BAHAMAS WHILE CUTOFF UPPER LOW EJECTS FROM THE SOUTHWESTERN U.S.
INTO THE OHIO VALLEY SATURDAY THROUGH MONDAY. TEMPERATURES WILL
CONTINUE THEIR IMPRESSIVE DEVIATIONS FROM CLIMATOLOGY WITH DAYTIME
HIGHS NEARLY 20 DEGREES ABOVE NORMAL AND NIGHTTIME DEVIATIONS OFTEN
EVEN LARGER AS CLOUD COVER LINGERS BENEATH THE SUBSIDENCE INVERSION
BORNE OF THE UPPER RIDGE. RAIN CHANCES ARE BOTH TOUGH TO RULE OUT
WITH SO MUCH LOW LEVEL MOISTURE BUT ALSO HARD TO GET EXCITED ABOUT
DUE TO THE UPPER RIDGE. THE EXCEPTION MAY BE MONDAY WHEN THE RIDGE
GETS BEAT DOWN SUFFICIENTLY FOR SOME HEIGHT FALLS LOCALLY. THEN
AGAIN, THIS USUALLY OCCURS MORE SLOWLY THAN PORTRAYED IN GUIDANCE.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 18Z...MOST OF THE PRECIP HAS DIED DOWN WITH A FEW EXCEPTIONS.
CEILINGS ARE LIKELY TO BE ALL OVER THE PLACE THIS AFTERNOON...EVENTUALLY
BECOMING ALL IFR SOMETIME TONIGHT. THE HRRR MODEL BRINGS CONVECTION
BACK INTO THE WESTERN TERMINALS THIS EVENING...HOWEVER THINK IT WILL
BE MORE OF A STABLE RAIN OR EVEN DRIZZLE AS WE HEAD THROUGH THE
OVERNIGHT HOURS. MODELS ARE HINTING AT SOME LIFR FOG AND THIS SEEMS
REASONABLE. CLOUD COVER AND THE STRONG SOUTHERLY GRADIENT MAY BE
A HINDERANCE. SOME RAIN ON THURSDAY HOWEVER COVERAGE WILL BE LESS
THAN TODAY.
EXTENDED OUTLOOK...POSSIBLE MVFR TO IFR CONDITIONS IN PCPN AND LOW
CEILINGS FROM THROUGH THURSDAY...OTHERWISE EXPECT VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 AM WEDNESDAY...SCA CONTINUES FOR ALL ZONES WITH
CONTINUED AND INCREASING SOUTHERLY FLOW BUILDING SEAS OVER 6 FT
ACROSS PORTIONS OF ALL MARINE ZONES. BERMUDA HIGH REMAINS THE MAIN
SURFACE FEATURE...KEEPING WINDS FROM THE SOUTH. COMBINATION OF
GRADIENT AND LOW LEVEL JET IS KEEPING SPEEDS IN THE 15 TO 20 KT
RANGE THROUGH THE PERIOD. ONLY MINIMAL CHANGES REQUIRED FOR
MORNING UPDATE.
DISCUSSION FROM 630 THIS MORNING FOLLOWS:
SMALL CRAFT ADVISORY CONDITIONS EXPECTED THRU THIS PERIOD. SFC
PRESSURE PATTERN THRU TONIGHT TO YIELD SSE-S WIND DIRECTIONS THIS
MORNING...BECOMING S-SSW BY MIDDAY AND CONTINUING THRU TONIGHT. A
TIGHTENING SFC PG WILL DEVELOP ACROSS THE LOCAL WATERS EARLY
TODAY...AND WILL REMAIN TIGHTENED THRU TONIGHT. THIS WILL YIELD 10
TO 20 KT SUSTAINED WIND SPEEDS THIS MORNING THAT COULD
OCCASIONALLY REACH 15 TO 25 KT FROM MIDDAY THROUGH THIS EVENING.
IN ADDITION...GUSTS COULD APPROACH 30 KT ESPECIALLY OVER SSTS THAT
ARE WELL INTO THE 60S. LOCAL SSTS HAVE ALREADY SHOWN AN INCREASE
FROM 24 HRS AGO DUE TO THE ONSHORE FLOW WITH LOW 60S COMMON NOW.
EXPECT THIS SLOW INCREASING TREND TO CONTINUE WITH LOW TO MID 60S
BECOMING MORE COMMON BY EARLY THU. AS A RESULT...SEA FOG
DEVELOPMENT SHOULD NOT BE AN ISSUE DURING THIS TIME PERIOD.
SIGNIFICANT SEAS WILL BUILD TO 4 TO 7 FT TODAY...AND PEAK 5 TO
8 FT LATE THIS AFTN THRU TONIGHT. THE 8 FOOTERS WILL PRIMARILY
OCCUR OVER THE WATERS OFF CAPE FEAR. WIND DRIVEN WAVES AT 6 TO 7
SECOND PERIODS WILL DOMINATE THE SEAS.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 3 AM WEDNESDAY... PERIOD INITIALIZES WITH A SMALL CRAFT
ADVISORY IN A MODERATELY PINCHED SOUTHWESTERLY GRADIENT FLOW WITH
SOME EMBEDDED ENERGY. A SLIGHT WESTWARD EXTENSION OF A RIDGE AXIS
INTO GA/FL ON THE PART OF THE OFFSHORE HIGH LEADS TO A SLIGHT
WEAKENING OF THE GRADIENT LATER THURSDAY INTO THURSDAY NIGHT AND
FRIDAY. WIND REMAINS MOSTLY SOUTHWESTERLY ON FRIDAY BUT IN A
LIGHTENED STATE. THE RIDGE AXIS SHOULD ALSO DISRUPT THE SWELL
ENERGY A BIT TO HELP FURTHER REDUCE DOMINANT WAVE HEIGHT.
LONG TERM /SATURDAY THROUGH SUNDAY/...
AS OF 3 AM WEDNESDAY... MUCH MORE OF A WARM SEASON PATTERN IN
PLACE WITH A WEST ATLANTIC HIGH DOMINATING AND A COMPLETE LACK OF
ANY FRONTS. THE MAIN DIFFERENCE PATTERN-WISE WILL BE THAT THE HIGH
WILL BE WEAKER AND FURTHER WEST THAN WHAT IS NORMALLY OBSERVED IN
THE WARM SEASON. AS SUCH WIND SPEEDS MAY WELL BE CAPPED AT 10KT AS
THE DIRECTION REMAINS SOUTH TO SOUTHWESTERLY. SEAS WILL AVERAGE 2
TO 3 AND OCCASIONALLY (WELL OFFSHORE) 4 FT.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL NOON EST THURSDAY FOR AMZ250-252-
254-256-270-274.
&&
$$
NEAR TERM...III
SHORT TERM...MBB
LONG TERM...MBB
AVIATION...DL
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
233 PM CST WED DEC 23 2015
.DISCUSSION...
MAIN LINE OF POTENTIALLY SEVERE TSTMS EXTENDS FROM MO BOOTHEEL
SOUTHWARD THROUGH EASTERN AR. SO FAR...SOME HALF INCH TO INCH HAIL
AND SOME WIND DAMAGE HAS OCCURRED ACROSS AR. OUT AHEAD OF THIS
LINE...SOME CONVECTIVE SHOWER DEVELOPMENT IS ONGOING. A FEW LTG
STRIKES HAVE JUST OCCURRED IN NW TN AND WESTERN KY. THIS INCREASE
IN DESTABILIZATION IS EXPECTED TO CONTINUE AS THE AFTERNOON WEARS
ON.
EARLIER THIS MORNING...SPC UPGRADED PART OF OUR AREA TO A MDT RISK.
SO...OVER ROUGHLY THE NW 2/3 OF THE MID STATE...WE HAVE A MDT RISK
IN EFFECT. TO OUR WEST...A TOR WATCH IS CURRENTLY IN EFFECT OVER
WESTERN TN UNTIL 8 PM. ADDITIONALLY...IT SHOULD BE NOTED THAT THE
WATCH IS A PDS...OR PARTICULARLY DANGEROUS SITUATION. HELICITY
VALUES ARE QUITE HIGH WITH THIS EVENT AND THESE HIGHER VALUES
CORRESPOND WELL WITH THE BEST FORCING AND INSTABILITY. THUS...ITS
JUST A MATTER OF TIME BEFORE THE WATCH IS EXTENDED EASTWARD TO
COVER THE MID STATE.
GOING FORWARD...I WILL INCLUDE CATEGORICAL POPS FOR TONIGHT AND
INCLUDE SVR WORDING WITH TORNADOS...DAMAGING WINDS AND LARGE HAIL
ALL BEING A VIABLE THREAT. THE TIMEFRAME STILL LOOKS LIKE THE 4PM
TO MIDNIGHT PERIOD. SOME RESIDUAL SHOWER AND NON SEVERE TSTM
ACTIVITY WILL PERSIST BEHIND THE SEVERE THREAT SO LOW POPS WILL
CONTINUE INTO THU MORNING.
BEHIND THIS SYSTEM...WE ARE STILL LOOKING AT A VERY MILD PATTERN.
THE SFC LOW LIFTS OFF WELL TO THE NORTH AND PREVENTS THE INTRUSION
OF ANY SEASONAL AIR.
ON FRIDAY...POPS WILL INCREASE AGAIN AS A WARM FRONT LIFTS
NORTHWARD. THE WARM FRONT WILL BE RATHER STRONG. IN FACT...AFTER A
HIGH ON FRIDAY IN THE MID 60S...LOW TEMPS WILL ONLY FALL TO THE
LOWER TO MID 60S. STILL CAN`T RULE OUT THE POTENTIAL FOR ONE OR TWO
STRONG STORMS WITH THE WARM FRONT BY FRI NT AS 850 MB FLOW WILL
REACH 30 KTS.
IN THE EXT FCST...STILL LOOKING AT A POWERFUL SYSTEM WHICH WILL
DEVELOP OVER TX ON SATURDAY. THIS FEATURE WILL LIFT OFF TO THE
NORTHEAST. EVENTUALLY...IT WILL DRAG A COLD FRONT THROUGH THE AREA
BY TUESDAY. THE SFC LOW CONFIGURATION DOES FEATURE SOME W-E
ELONGATION AND THUS...THE SEVERE THREAT WILL BE REDUCED. STILL
THOUGH...NEG SHOWALTER VALUES WILL ATTEMPT TO MOVE INTO THE MID
STATE ALONG WITH 50 KTS OF WIND AT THE 850 MB LEVEL. SO...CANNOT
RULE OUT STRONG STORMS ON MON AND MON NT.
TEMPS THOUGH THE EXTENDED WILL CONTINUE TO BE RATHER MILD AND COULD
SET RECORDS. RECORDS FOR THE DATE MAY BE SET ON FRIDAY AND FRIDAY NT
FOR BOTH MAX TEMPS AND MIN TEMPS. BEHIND THE FROPA...THE PREVAILING
AIRMASS LOOKS TO BE OF PACIFIC ORIGIN. FURTHERMORE...UPPER LEVEL
PATTERN GANGS ON TO THE DOMINANCE OF ELEVATED HEIGHT FIELDS. WE ARE
CERTAINLY ON OUR WAY TO THE 2ND WARMEST DECEMBER ON RECORD FOR
NASHVILLE.
&&
.AVIATION...
12Z TAF DISCUSSION.
MVFR/IFR CONDITIONS WILL PREVAIL THIS TAF PERIOD WITH NUMEROUS
SHOWERS AND THUNDERSTORMS TO AFFECT ALL AIRPORTS. BASED TIMING
HEAVILY ON THE HRRR MODEL...WITH ONE ROUND OF SHRA/TSRA ARRIVING
LATE WED MORN/EARLY AFT THEN MAIN ROUND OF SHRA/TSRA REACHING
TERMINALS BETWEEN 23-03Z. SOUTH WINDS UP TO 20 KTS WITH GUSTS TO
30 KTS TODAY AT AIRPORTS...ALTHOUGH GUSTY WINDS OVER 40KT POSSIBLE
IN ANY TSRA.
&&
.PRELIMINARY POINT TEMPS/POPS...
NASHVILLE 57 73 56 66 65 / 90 20 30 70 70
CLARKSVILLE 50 70 50 67 63 / 90 20 30 70 70
CROSSVILLE 61 71 58 68 63 / 80 30 30 70 60
COLUMBIA 58 74 58 68 65 / 90 20 40 70 70
LAWRENCEBURG 59 73 58 69 65 / 90 30 40 70 60
WAVERLY 52 72 52 68 64 / 80 20 30 70 70
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM/AVIATION........05
LONG TERM..................21
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1138 AM CST WED DEC 23 2015
.DISCUSSION...
IMPULSE WORKING NORTHWARD ACROSS EASTERN AREAS OF THE MID STATE.
MODEL MRH FIELDS DO LEAN TOWARD BEING MORE BULLISH ACROSS EASTERN
AREAS THROUGH 00Z. WILL GO AHEAD AND INCREASE POPS EAST FOR THE
PERIOD 18Z THRU 22Z. OTW...MAIN LINE OF POTENTIALLY SEVERE TSTMS
IS NOW WORKING THROUGH EASTERN AR AND THE MO BOOTHEEL. THAT LINE
WILL BE HOLDING TOGETHER AS IT MOVES EASTWARD. DEVELOPMENT OUT
AHEAD OF THAT MAIN LINE IS STILL POSSIBLE. SAT TRENDS DO INDICATE
A FEW BREAKS IN THE CLOUDINESS ACROSS WESTERN TN AND NRN MS. THIS
WILL ACT TO ONLY DESTABILIZE CONDITIONS EVEN FURTHER.
NO OTHER CHANGES TO THE FCST AT THIS TIME...BUT AGAIN...WILL UP
POPS EAST.
&&
.AVIATION...
12Z TAF DISCUSSION.
MVFR/IFR CONDITIONS WILL PREVAIL THIS TAF PERIOD WITH NUMEROUS
SHOWERS AND THUNDERSTORMS TO AFFECT ALL AIRPORTS. BASED TIMING
HEAVILY ON THE HRRR MODEL...WITH ONE ROUND OF SHRA/TSRA ARRIVING
LATE WED MORN/EARLY AFT THEN MAIN ROUND OF SHRA/TSRA REACHING
TERMINALS BETWEEN 23-03Z. SOUTH WINDS UP TO 20 KTS WITH GUSTS TO
30 KTS TODAY AT AIRPORTS...ALTHOUGH GUSTY WINDS OVER 40KT POSSIBLE
IN ANY TSRA.
&&
.PRELIMINARY POINT TEMPS/POPS...
NASHVILLE 74 60 73 56 70 / 70 90 30 40 70
CLARKSVILLE 72 54 71 51 65 / 70 90 20 30 70
CROSSVILLE 69 62 71 59 69 / 60 80 70 40 70
COLUMBIA 73 61 74 57 71 / 70 90 40 40 70
LAWRENCEBURG 72 62 73 58 72 / 70 90 50 50 70
WAVERLY 72 55 70 52 68 / 80 80 20 40 70
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM/AVIATION........27/UNGER
LONG TERM..................21
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
1046 AM CST WED DEC 23 2015
.DISCUSSION...
CURRENTLY...A LINE OF STRONG TO SEVERE THUNDERSTORMS EXTEND ACROSS
NE AR INTO CNTRL AR WHILE SCATTERED SHOWERS AND A FEW
THUNDERSTORMS ARE OCCURRING AHEAD OF THIS LINE. WITH INCREASING
INSTABILITY ACROSS NW TN...CONDITIONS REMAIN FAVORABLE FOR MORE
SEVERE THUNDERSTORMS AND POSSIBLE TORNADOES IN WATCH #558 OVER NE
AR...MO BOOTHEEL AND NW TN.
THIS AFTERNOON...EXPECT A SHORTWAVE TO EJECT OUT OF SRN AR INTO
THE MIDSOUTH INCREASING THE RISK FOR SEVERE WEATHER OVER MEMPHIS
AND JACKSON AND AREAS SOUTH OF I-40. PLENTY OF DYNAMICS AND
INSTABILITY WILL SUPPORT THE BEST CHANCE OF TORNADOES THIS
AFTERNOON FROM SUPERCELLS. LARGE HAIL AND DAMAGING WINDS WILL ALSO
HAVE A HIGHER THREAT.
THIS EVENING...THE UPPER SHORTWAVE MOVES TO THE NORTH AND 500MB
HTS RISE. THE RISK FOR SEVERE WEATHER WILL DECREASE AHEAD OF A WEAK
COLD FRONT AS THE MAIN DYNAMICS SHIFT TO THE NORTH.
SWC
&&
.PREV DISCUSSION... /ISSUED 522 AM CST WED DEC 23 2015/
.OUTBREAK OF SEVERE THUNDERSTORMS EXPECTED ACROSS THE MID SOUTH
ESPECIALLY THIS AFTERNOON AND TONIGHT...
DISCUSSION...10Z SURFACE ANALYSIS PLACES A STRONG SURFACE LOW
ACROSS SOUTH CENTRAL KANSAS AND A DRYLINE EXTENDING SOUTH FROM
THE LOW ACROSS WESTERN OKLAHOMA AND WESTERN TEXAS. SOUTHERLY WINDS
IN ADVANCE OF THIS SURFACE LOW HAVE ALREADY ADVECTED LOWER TO
MIDDLE 60 DEWPOINT AIR UP INTO THE LOWER MISSISSIPPI VALLEY THIS
MORNING. WATER VAPOR SATELLITE TRENDS INDICATE A DEEP LONGWAVE
UPPER LEVEL TROUGH OVER THE CENTRAL AND SOUTHERN PLAINS AND A LEAD
SHORTWAVE TROUGH OVER THE LOWER MISSISSIPPI VALLEY. AT THE SURFACE A
WARM FRONT IS MOVING ACROSS THE MID SOUTH AS OF DISCUSSION.
CONSEQUENTLY...SHOWERS AND THUNDERSTORMS HAVE EXPANDED IN COVERAGE
ACROSS ARKANSAS OVERNIGHT. AS OF 4 AM CST...TEMPERATURES ACROSS
THE MID SOUTH ARE IN THE 60S AT MOST LOCATIONS. SEVERE
THUNDERSTORM POTENTIAL THIS AFTERNOON AND TONIGHT IS THE
PREDOMINANT FOCUS IN THIS MORNING/S FORECAST ISSUANCE.
SHOWERS AND THUNDERSTORMS OVER ARKANSAS AND SOUTHERN MISSISSIPPI
WILL SPREAD ACROSS THE MID SOUTH THIS MORNING. A STRONG TO SEVERE
THUNDERSTORM IS POSSIBLE THIS MORNING BUT THINK THE BULK OF THE
SEVERE THUNDERSTORM THREAT WILL OCCUR MAINLY THIS AFTERNOON AND
TONIGHT AS A NEGATIVELY TILTED UPPER LEVEL TROUGH AND A STRONG
COLD FRONT ROTATE THROUGH THE MIDDLE AND LOWER MISSISSIPPI
VALLEYS.
RECORD WARMTH WITH HIGHS TODAY IN THE LOWER TO MIDDLE 70S COMBINED
WITH FAVORABLE UPPER LEVEL DIVERGENCE PRODUCED BY THE RIGHT EXIT
REGION OF A 130 KT UPPER LEVEL JET...DECENT 50-80 DM 500 MB MID
LEVEL HEIGHT FALLS...SURFACE BASED CAPE VALUES BETWEEN 1500-2O00
J/KG...STEEP 700-500 MB LAYER MID LEVEL LAPSE RATES AROUND 7
C/KM...0-1 KM STORM RELATIVE HELICITIES AROUND 300
M2/S2...STRONGLY CURVED HODOGRAPHS...FAVORABLE LCL/S AND 0-6 KM
BULK SHEAR VALUES IN EXCESS OF 70 KTS SUGGESTS A VERY GOOD
POTENTIAL FOR THUNDERSTORMS TO BECOME SEVERE ACROSS THE MID SOUTH
ESPECIALLY DURING THE AFTERNOON AND EVENING HOURS. LARGE
HAIL...DAMAGING WINDS...AND TORNADOES ARE ALL POSSIBLE WITH ANY
THUNDERSTORMS THAT REACH SEVERE LIMITS. A POTENTIAL ALSO EXISTS
FOR SIGNIFICANT TORNADOES ACROSS MUCH OF THE MID SOUTH WITH THE
I-40 CORRIDOR IN THE CENTER OF THE RISK AREA. SHORT TERM MESOSCALE
TRENDS WILL CLOSELY BE MONITORED THROUGHOUT THE DAY IN CASE ANY
ADJUSTMENTS ARE NEEDED TO THE CURRENT FORECAST AND HAZARDOUS
WEATHER OUTLOOK. RESIDENTS OF THE MID-SOUTH AND HOLIDAY TRAVELERS
SHOULD STAY TUNED TO THE FORECAST TODAY AND BE PREPARED TO TAKE
APPROPRIATE SAFETY PRECAUTIONS IF SEVERE WEATHER THREATENS THEIR
LOCATION.
THE SEVERE THUNDERSTORM THREAT SHOULD BEGIN TO PUSH EAST OF THE
MID SOUTH TONIGHT AS A STRONG COLD FRONT SWEEPS THROUGH THE
AREA...BRINGING AN GRADUAL END TO SHOWER AND THUNDERSTORM CHANCES
BY CHRISTMAS EVE. HOWEVER...THIS IS NOT EXPECTED TO LAST LONG AS
THIS FRONT WILL STALL OUT AND RETURN BACK NORTH AS A WARM FRONT
CHRISTMAS EVE NIGHT INTO CHRISTMAS DAY. ANOTHER CHANCE FOR STRONG
TO SEVERE THUNDERSTORMS WILL BE POSSIBLE DURING THIS AND WILL BE
CLOSELY WATCHED IN UPCOMING FORECASTS.
LONG TERM MODELS INDICATE THE MID SOUTH WILL REMAIN IN A WARM
SECTOR FOR THE UPCOMING WEEKEND RESULTING IN A CONTINUED CHANCE
FOR SHOWERS AND THUNDERSTORMS. AN UPPER LEVEL LOW IS EXPECTED TO
DEVELOP AND MOVE FROM THE SOUTHERN PLAINS INTO THE MIDDLE/LOWER
MISSISSIPPI VALLEYS BY EARLY NEXT WEEK. THIS MAY POSE YET ANOTHER
POTENTIAL FOR STRONG TO SEVERE THUNDERSTORMS BETWEEN SUNDAY NIGHT
TO MONDAY NIGHT. CONFIDENCE IS LOW AT THIS MOMENT DUE TO
PERSISTENT RUN TO RUN CONTINUITY ISSUES WITH THIS PARTICULAR
SYNOPTIC SYSTEM. STAY TUNED...
CJC
&&
.AVIATION...
AVIATION...
12Z TAFS
DEEP SUBTROPICAL MOISTURE WILL PREVAIL TODAY...WITH STRONG
VERTICAL WIND SHEER SUPPORTIVE OF A DEVELOPING LINE OF INTENSE
SURFACE-TSRA AFTER 18Z. HRRR AND NAM INDICATED A BROKEN LINE OF
TSRA. FOR THIS MORNING...SHRA/TSRA WILL BE ROOTED IN AN ELEVATED
LAYER ABOVE THE MOIST LOW LEVEL INVERSION.
PROSPECTS FOR A MVFR/VFR LATE EVENING MEM ARRIVAL PUSH APPEAR
PROMISING...ASSUMING POST FRONTAL STRATUS DEPICTED ON THE 06Z NAM
BUFR SOUNDINGS DOES NOT MATERIALIZE.
PWB
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1215 PM CST WED DEC 23 2015
.AVIATION...
CLEARING SKIES THIS AFTERNOON BEHIND A WEAK FRONT THAT MOVED
THROUGH THE FORECAST AREA THIS MORNING. MODERATE TO STRONG WINDS
WILL GRADUALLY DIMINISH BY MID-LATE AFTERNOON AS THE SURFACE
GRADIENT RELAXES BEHIND THE FRONT. CLEAR SKIES AND LIGHT WINDS
EXPECTED TONIGHT. PATCHY FOG POSSIBLE TOMORROW MORNING BETWEEN
HOUSTON METRO AREA AND THE COAST...HOWEVER HIGH CLOUDS SHOULD
LIMIT ANY DENSE STRATUS/FOG FORMATION. MVFR CIG CONDITIONS
POSSIBLE AT KGLS AND KLBX TOMORROW MORNING AS A WEAK STATIONARY
FRONT ALONG THE COAST BEGINS TO MOVE INLAND AS A WEAK WARM FRONT.
44
&&
.PREV DISCUSSION... /ISSUED 1130 AM CST WED DEC 23 2015/
DISCUSSION...
FRONTAL BOUNDARY CONTINUING TO MOVE ACROSS SE TX AT PRESENT AND WE
ARE SEEING MUCH LOWER DEWPTS IN ITS WAKE. THE PATCHY FOG ALONG THE
COAST/BAYS SHOULD NOT LAST MUCH LONGER THIS AFTN. OTHERWISE NO BIG
CHANGES WITH THE CURRENT FCST PLANNED ATTM. 41
PREV DISCUSSION... /ISSUED 533 AM CST WED DEC 23 2015/
AVIATION...
A S/WV TROUGH WILL MOVE EAST OF THE REGION TODAY. STILL SOME
POTENTIAL FOR A FEW SHOWERS OVER THE NORTHERN TAF SITES THIS
MORNING. MUCH DRIER AIR WILL WORK INTO THE REGION FROM THE WEST BY
AFTERNOON WITH SFC WINDS VEERING TO THE W-SW. VFR CONDS EXPECTED
TO DEVELOP BETWEEN 17-19Z AREAWIDE. FCST SOUNDINGS SHOW CLEAR
SKIES OVERNIGHT. COASTAL TAF SITES MAY SUFFER SOME VSBY
RESTRICTIONS LATE TONIGHT. THE HRRR SHOWS AN AREA OF SEA FOG
DEVELOPING OFF THE LOUISIANA COAST AND MOVING WEST TONIGHT. THE
FOG WILL PROBABLY IMPACT KGLS/KLBX AFTER 08Z AND KHOU AFTER 10Z.
43
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 55 77 65 78 69 / 10 10 40 50 50
HOUSTON (IAH) 56 80 67 79 69 / 10 20 40 50 40
GALVESTON (GLS) 63 74 67 74 68 / 10 20 40 50 30
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT SHOULD EXERCISE CAUTION UNTIL 4 PM CST THIS
AFTERNOON FOR THE FOLLOWING ZONES: GALVESTON BAY...
MATAGORDA BAY.
SMALL CRAFT ADVISORY UNTIL 4 PM CST THIS AFTERNOON FOR THE
FOLLOWING ZONES: WATERS FROM FREEPORT TO THE MATAGORDA SHIP
CHANNEL 20 NM TO 60 NM...WATERS FROM FREEPORT TO THE
MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS FROM HIGH ISLAND
TO FREEPORT 20 TO 60 NM...WATERS FROM HIGH ISLAND TO
FREEPORT OUT 20 NM.
&&
$$
DISCUSSION...41
AVIATION/MARINE...44
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1130 AM CST WED DEC 23 2015
.DISCUSSION...
FRONTAL BOUNDARY CONTINUING TO MOVE ACROSS SE TX AT PRESENT AND WE
ARE SEEING MUCH LOWER DEWPTS IN ITS WAKE. THE PATCHY FOG ALONG THE
COAST/BAYS SHOULD NOT LAST MUCH LONGER THIS AFTN. OTHERWISE NO BIG
CHANGES WITH THE CURRENT FCST PLANNED ATTM. 41
&&
.PREV DISCUSSION... /ISSUED 533 AM CST WED DEC 23 2015/
AVIATION...
A S/WV TROUGH WILL MOVE EAST OF THE REGION TODAY. STILL SOME
POTENTIAL FOR A FEW SHOWERS OVER THE NORTHERN TAF SITES THIS
MORNING. MUCH DRIER AIR WILL WORK INTO THE REGION FROM THE WEST BY
AFTERNOON WITH SFC WINDS VEERING TO THE W-SW. VFR CONDS EXPECTED
TO DEVELOP BETWEEN 17-19Z AREAWIDE. FCST SOUNDINGS SHOW CLEAR
SKIES OVERNIGHT. COASTAL TAF SITES MAY SUFFER SOME VSBY
RESTRICTIONS LATE TONIGHT. THE HRRR SHOWS AN AREA OF SEA FOG
DEVELOPING OFF THE LOUISIANA COAST AND MOVING WEST TONIGHT. THE
FOG WILL PROBABLY IMPACT KGLS/KLBX AFTER 08Z AND KHOU AFTER 10Z.
43
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 79 55 77 65 78 / 20 10 10 40 50
HOUSTON (IAH) 82 56 80 67 79 / 30 10 20 40 50
GALVESTON (GLS) 77 63 74 67 74 / 20 10 20 40 50
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT SHOULD EXERCISE CAUTION UNTIL 4 PM CST THIS
AFTERNOON FOR THE FOLLOWING ZONES: GALVESTON BAY...
MATAGORDA BAY...WATERS FROM FREEPORT TO THE MATAGORDA SHIP
CHANNEL OUT 20 NM...WATERS FROM HIGH ISLAND TO FREEPORT OUT
20 NM.
SMALL CRAFT ADVISORY UNTIL 4 PM CST THIS AFTERNOON FOR THE
FOLLOWING ZONES: WATERS FROM FREEPORT TO THE MATAGORDA SHIP
CHANNEL 20 NM TO 60 NM...WATERS FROM HIGH ISLAND TO
FREEPORT 20 TO 60 NM.
&&
$$
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE
.SHORT TERM...TONIGHT AND THURSDAY
ISSUED AT 309 PM CST WED DEC 23 2015
PLENTY OF FORECAST CHALLENGES NEXT 24 HOURS CONCERNING WITH GUST
POTENTIAL AND AMOUNT OF RAINFALL AND RAINFALL RATES WHICH MAY
IMPACT ANY LINGERING RIVER FLOOD PROBLEMS AS WELL AS PRODUCE ANY
SMALL STREAM URBAN FLOODING ISSUES. SEE THE HYDROLOGY SECTION
BELOW FOR THE LATEST DETAIL ON FLOODING ISSUES. OTHER ISSUES
CONCERN CHANGE OVER TO SNOW TONIGHT.
A STRONG SHORT WAVE LIFTS NORTHEAST OVER THE GREAT LAKES REGION
THROUGH TONIGHT. AN ASSOCIATED SURFACE LOW WILL TRACK FROM IOWA
LATE THIS AFTERNOON TO CENTRAL UPPER MICHIGAN AROUND MIDNIGHT AND
DEEPEN. THE LOW WILL ALSO A DRAG WARM FRONT OVER NORTHEAST
WISCONSIN THIS AFTERNOON INTO THIS EVENING. MILDER AIR SPREADING
INTO EAST CENTRAL AND FAR NORTHEAST WISCONSIN WILL ALLOW A VERY
MILD AIR MASS WITH POSSIBLE RECORD HIGHS TO INVADE THE AREA.
HIGHEST TOTAL TOTALS NUMBERS IN THE LOWER 50S MID EVENING AS PER
GRB BUFKIT DATA. THIS WILL ALSO RESULT IN A MORE UNSTABLE AIR
MASS AND MAY PROMOTE BETTER MIXING OF STRONG WINDS TO THE
SURFACE...ESPECIALLY WITH ANY CONVECTION. HRRR PROGGED DEVELOPMENT
OF THIS CONVECTION OF CONCERN ALONG AND AHEAD OF THE FRONT OVER
NORTHERN MO AND SOUTHERN IOWA AND SO FAR IS VERIFYING. THIS NEXT
ROUND IS PROGGED TO SWEEP OVER THE AREA THIS EVENING.
PROBLEM 2 WITH THE WINDS OCCUR LATE TONIGHT AS THE DEEPENING LOW
PRESSURE DEPARTS NORTHEAST AND LEAVES A STRONG PRESSURE GRADIENT
OVER MUCH OF THE STATE. A STRONG PRESSURE CHANGE COUPLET SLIDES
OVER NORTHEAST WISCONSIN IN THE WAKE OF THE SURFACE LOW. WILL
CONTINUE WITH THE WIND ADVISORY AND WILL ISSUE FOR DOOR DUE TO THE
WESTERLY COMPONENT. ITS POSSIBLE THE HIGH WIND ADVISORIES AND
WARNINGS MAY NEED TO BE EXPANDED DEPENDING ON THE LOW PRESSURE
TRACK.
PCPN TYPE INITIALLY NOT AN ISSUE BUT COULD SEE SOME HAIL OR
GRAUPEL WITH ANY CONVECTION THIS EVENING. LATER EVENING INTO THE
MORNING...COLDER AIR POURING IN WILL CHANGE THE PCPN TYPE TO
SNOW. WHILE SNOW RANGES MOSTLY IN THE 2-4 RANGES FOR NC WI...THE
SNOW WIND COMBO WARRANTS AN ADVISORY LATER TONIGHT. RADAR SOUTHERN
LOOP SUGGESTS REACHING NC WI AND CHANGEOVER AND ISSUE. BUT DID
NOTICE SOME THUNDER WITH THE SURFACE LOW OVER IOWA.
SYSTEM GRADUALLY DEPARTS THURSDAY WITH DIMINISHING WINDS IN THE
MORNING. TEMPERATURES NEAR STEADY ON THURSDAY.
.LONG TERM...THURSDAY NIGHT THROUGH WEDNESDAY
ISSUED AT 309 PM CST WED DEC 23 2015
AMPLIFIED MEAN FLOW TO REMAIN INTACT THRU THE END OF THE WORK WEEK
WITH AN ERN PACIFIC UPR RDG...WRN CONUS UPR TROF AND BERMUDA UPR
RDG. THE UPR TROF IS FCST TO CLOSE OFF INTO AN UPR LOW OVER WEST
TX THIS WEEKEND BEFORE LIFTING NE INTO THE GREAT LAKES EARLY NEXT
WEEK. PCPN CHCS WL BE FOCUSED FRI NGT/SAT ASSOCIATED WITH A TIGHT
BAROCLINIC ZONE/JET ENERGY AND MON NGT/TUE WITH THE UPR LOW/
ASSOCIATED SFC LOW. PCPN TYPE ISSUES WL ALSO BE A PROBLEM WITH
BOTH OF THESE SYSTEMS AS TEMPS FLUCTUATE BELOW FREEZING AT NGT AND
RISE ABOVE FREEZING IN PLACES DURING THE DAY. THERE IS SNOW
ACCUMULATION POTENTIAL FOR CNTRL/NRN WI FRI NGT AND OVER THE
ENTIRE AREA MON NGT/TUE.
A WEAK AREA OF HI PRES IS FCST TO APPROACH SRN SECTIONS OF THE
GREAT LAKES THU NGT AND SHOULD KEEP THE FCST AREA DRY. IT MAY TAKE
MOST OF THE NGT TO TRY AND SCOUR OUT LINGERING LOW/MID-LEVEL
MOISTURE...THUS PARTLY TO MOSTLY CLOUDY SKIES SHOULD SUFFICE. MIN
TEMPS TO RANGE FROM THE MID TO UPR TEENS NORTH...LWR 20S CNTRL...
AND MID TO UPR 20S E-CNTRL WI. THESE DRY CONDITIONS ARE EXPECTED
TO PERSIST THRU CHRISTMAS DAY AS THE SFC HI SLIDES EAST TOWARD THE
ERN GREAT LAKES. UNDER PARTLY CLOUDY SKIES AND RELATIVELY LIGHT
WINDS...LOOK FOR MAX TEMPS TO REACH THE LWR TO MID 30S NORTH...
MID TO UPR 30S SOUTH.
FCST CONFIDENCE DROPS RATHER QUICKLY LATE FRI NGT INTO SAT AS AN
UPR TROF DEEPENS OVER THE ROCKIES...INDIVIDUAL SHORTWAVES EJECT
OUT OF THIS TROF NEWD THRU THE CNTRL CONUS...A STALLED FRONTAL
BOUNDARY TO OUR SOUTH BECOMES MORE ACTIVE AND GULF MOISTURE LIFTS
NORTH ALONG THIS FRONTAL BOUNDARY TOWARD THE GREAT LAKES. MODELS
BRING THE LEADING EDGE OF PCPN INTO NE WI LATE FRI NGT WHEN TEMPS
WL BE COLD ENUF TO ALLOW PCPN TO FALL AS ALL SNOW. THE ISSUES FOR
SAT ARE WHERE THE HIGHEST QPF WL FALL AND WHAT THE PCPN TYPE WL
BE. THIS IS WHERE THE MODELS DIFFER AS THE GFS/ECMWF FOCUS THE
HEAVIER PCPN TO THE NORTH AND ALLOW FOR WARMER AIR TO LIFT FARTHER
NORTH INTO WI...THUS A MIXED PCPN EVENT FOR CNTRL/E-CNTRL WI WITH
SNOW NORTH. THE GEM IS FARTHEST SOUTH WITH THE HEAVIER PCPN (SRN
WI) AND COOLER AIR...THUS KEEPING ALL OUR PCPN AS ALL SNOW. THE
BETTER FRONTOGENETICAL FORCING SIGNAL AND LOCATION OF THE BEST
LIFT FROM THE RIGHT ENTRANCE REGION OF THE UPR JET FAVOR NRN WI
WITH THE HIGHER QPF...THUS WL CONT THE MENTION OF SNOW NORTH AND
SNOW BECOMING MIXED WITH RAIN FOR CNTRL/E-CNTRL WI. POTENTIAL SNOW
ACCUMULATION OF 3-5" IS POSSIBLE OVER THE NORTH FRI NGT INTO
SAT...BUT ANY WAVERING ON THE STRONGER LIFT/FORCING COUDL ALTER
THESE VALUES.
AS THE STRONGER DYNAMICS SHIFT TO THE EAST SAT NGT...MODELS
INDICATE CAA TO TAKE OVER ACROSS WI...THUS ANY LINGERING RAIN OVER
CNTRL OR E-CNTRL WI WL TRANSITION TO ALL SNOW. DO NOT ANTICIPATE
MUCH (IF ANY) ADDITIONAL ACCUMULATION SAT NGT AS MOST OF THE
MOISTURE TO HAVE BEEN SHUNTED EAST. A STRONG AREA OF HI PRES IS
FCST TO BUILD ACROSS THE UPR MS VALLEY ON SUNDAY AND SEND ENUF DRY
AIR INTO WI TO ALLOW SKIES TO BECOME AT LEAST PARTLY CLOUDY.
DESPITE THE CAA AND NORTH WINDS AT 5 TO 15 MPH...MAX TEMPS ARE
FCST TO REMAIN ABOVE NORMAL ON SUNDAY BY AROUND 5 DEGS (MID 20S
N-CNTRL TO LWR 30S E-CNTRL WI).
THE CORE OF THIS STRONG HI PRES IS PROGGED TO MOVE ACROSS WRN
ONTARIO SUNDAY NGT AND VEER THE WINDS TO THE NE. WL HAVE TO WATCH
FOR POTENTIAL OF LK EFFECT SNOW SHWRS FROM LK MI AS TEMPS/DELTA-T
VALUES WOULD SUPPORT THE DEVELOPMENT OF LIGHT SNOW. ONE NEGATIVE
IS THAT THE WINDS CONT TO VEER THRU THE NGT (FROM NORTH TO
E-NE)...THUS IT MAY PROVE DIFFICULT FOR SNOW BANDS TO FOCUS ON ANY
ONE PARTICULAR AREA. OTHERWISE...THE OTHER BIG STORY WL BE THE
APPROACH OF ANOTHER STRONG AREA OF LOW PRES/CLOSED UPR LOW INTO
THE MID-MS VALLEY ON MON. LATEST THINKING IS THAT THERE WL BE ENUF
DRY AIR ON GUSTY EAST WINDS FROM ONTARIO HI PRES TO DELAY THE
ONSET OF ANY PCPN INTO NE WI ON MON. HAVE REDUCED POPS AND WOULD
EXPECT ALMOST A COMPLETELY DRY DAY FOR MON WITH MAX TEMPS IN THE
UPR 20S TO LWR 30S.
MODELS CONT TO DIFFER WITH THE TIMING/EVENTUAL TRACK OF THIS
STRONG SYSTEM MON NGT INTO TUE WITH THE GFS/GEM FAVORING A
QUICKER/FARTHER EAST TRACK VERSUS THE SLOWER/FARTHER WEST TRACK OF
THE ECMWF. THE GFS/GEM SOLUTION WOULD PROVIDE A QUICK-HITTING SNOW
EVENT FOR MAINLY THE SE HALF OF WI MON NGT BEFORE PULLING AWAY ON
TUE. THE ECMWF SOLUTION WOULD BRING A SWATH OF SNOW ACROSS ALL
OF NE WI MON NGT BEFORE MIXING IN RAIN OVER CNTRL/E-CNTRL WI ON
TUE WITH ADDITIONAL SNOWS FOR NRN WI. IF THE ECMWF SOLUTION
PREVAILS...WE WOULD BE LOOKING AT HEADLINES FOR SNOW...HOWEVER
THERE IS TOO MUCH UNCERTAINTY YET SO HAVE FOLLOWED A MODEL BLEND
FOR NOW WITH HIGHER CHC POPS IN THE FCST FOR BOTH MON NGT AND TUE.
EVEN GOING INTO WED...THERE IS MODEL DISAGREEMENT WITH RESPECT TO
THE TRACK OF THE SECONDARY/WEAKER UPR LOW THAT WOULD LIFT NE INTO
THE REGION. SINCE MODELS ARE INCONSISTENT WITH THIS
FEATURE...PREFER TO KEEP THE FCST DRY FOR NOW...BUT WOULD EXPECT
SOME SMALL POPS TO BE ADDED AS WE GET CLOSER TO WED.
&&
.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1110 AM CST WED DEC 23 2015
WIDESPREAD IFR/LIFR CONDITIONS TODAY INTO TONIGHT AS RAIN
OVERSPREADS THE AREA. THERE IS A CHANCE FOR THUNDERSTORMS LATER
AFTERNOON INTO THIS EVENING. OF MORE OF A CONCERN...LLWS
CONDITIONS EXPECTED THIS AFTERNOON INTO TONIGHT. SOME OF THESE
STRONG WINDS ALOFT COULD MIX DOWN TO THE SURFACE TONIGHT TO
PRODUCE WIND GUSTS TO 45 KTS...MAINLY OVER THE EAST HALF OF THE
STATE.
&&
.MARINE...
ISSUED AT 309 PM CST WED DEC 23 2015
HIGH-END GALES ARE STILL LIKELY WITH THIS STORM....BUT WILL
MENTION STORM FORCE WIND GUSTS. IN ADDITION WILL ALSO MENTION A
PERIOD OF FOG THOUGH THE EVENING HOURS.
&&
.HYDROLOGY...
ISSUED AT 309 PM CST WED DEC 23 2015
MOST RIVERS HAVE RECOVERED FROM THE HEAVY RAINS OVER A WEEK
AGO...EXCEPT FOR THE LOW LYING AREAS ALONG THE WOLF RIVER SOUTH OF
SHAWANO TO LAKE POYGAN. WITH THIS RAINFALL EXPECTED TO BE IN A
SHORTER TIME FRAME...AN INCH OF RAIN COULD PRODUCE ENOUGH RUN OFF
FOR SOME MINOR URBAN SMALL STREAM FLOODING. THIS WOLF RIVER LEVELS
MAY HOLD STEADY FOR A FEW MORE DAYS WITH THIS ADDITIONAL RAINFALL.
BUT LATEST RADAR TRENDS SUGGEST SOME DRY SLOTTING AS AN AREA OF
ELEVATED CONVECTION IS SWEEPING NORTHEAST OF THE AREA...WITH THE
NEXT ROUND OF CONVECTION APPROACHING FROM IOWA. AS A RESULT RAIN
AMOUNTS TO BE LESS ROUGHLY FORM 0.30 TO 0.50. SEE
WEATHER.GOV/AHPS FOR AVAILABLE FORECASTS FOR NORTHEAST WISCONSIN
RIVERS.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM 10 PM THIS EVENING TO NOON CST THURSDAY FOR
WIZ020-021-031-037>040-045-048>050-073-074.
HIGH WIND WARNING FROM 10 PM THIS EVENING TO NOON CST THURSDAY
FOR WIZ022.
WINTER WEATHER ADVISORY FROM 8 PM THIS EVENING TO 4 AM CST
THURSDAY FOR WIZ005-010.
&&
$$
SHORT TERM.....TDH
LONG TERM......AK
AVIATION.......TDH
MARINE.........TDH
HYDROLOGY......TDH