Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 02/16/15
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
501 PM MST SUN FEB 15 2015
.UPDATE...
ISSUED AT 456 PM MST SUN FEB 15 2015
TRAVEL IMPACTS ALONG INTERSTATE 70 NEAR VAIL PASS CONTINUE LATE
THIS AFTERNOON AND SPOTTERS REPORTING MODERATE TO HEAVY SNOW STILL
FALLING AND SLOW TRAVEL. HAVE ADJUST POP GRIDS SLIGHTLY IN THIS
AREA TO FIT CURRENT TRENDS. EXPECT A LULL IN ACTIVITY AFTER 1900
THIS EVENING...WITH SNOW PICKING BACK UP AFTER 3 AM BASED ON
LATEST HRRR GUIDANCE.
&&
.SHORT TERM...(TONIGHT THROUGH MONDAY NIGHT)
ISSUED AT 300 PM MST SUN FEB 15 2015
A COLD FRONT MOVING SOUTHWARD AHEAD OF AN UPPER LEVEL SHORT WAVE
TROUGH WAS POSITIONED ALONG A KBCE-KAIB-KMTJ-KLXV LINE AT 2 PM
MST. WINDS HAD SHIFTED TO THE NORTHWEST AND INCREASED TO 15 TO 20
MPH WITH GUSTS TO 30 MPH AT A NUMBER OF LOCATIONS IN THE WAKE OF
THE FRONT. ALSO BEHIND THE FRONT...LIGHT PRECIPITATION HAD STARTED
WHICH WAS EXPECTED. KEEO REPORTED MIXED PHASE PRECIPITATION WHICH
BEGAN AS LIGHT RAIN AND CHANGED OVER TO SNOW. MEANWHILE...WEB CAMS
INDICATED LIGHT SNOW IN THE PARK RANGE ABOVE KSBS AS DID CAMS FROM
VAIL PASS AND THE VAIL SKI AREAS. SNOW WILL CONTINUE IN THE
NORTHERN AND CENTRAL MOUNTAINS DURING THE REMAINDER OF THE
AFTERNOON AS THE SHORTWAVE TROUGH MOVES OVERHEAD. ADDITIONAL LIFT
PROVIDED BY JET LEVEL DIVERGENCE AND OROGRAPHIC LIFT.
THOUGH THE SHORTWAVE TROUGH AXIS MOVES EAST OF THE DIVIDE THIS
EVENING...LATEST MODELS INDICATED THAT LIGHT TO MODERATE SNOWFALL
WILL CONTINUE OVER THE NORTHERN AND CENTRAL DIVIDE MOUNTAINS
THROUGH THE NIGHT DUE TO OROGRAPHIC LIFT IN AN ENVIRONMENT
FEATURING STEEP LAPSE RATES OF 7.5 TO 8.0 DEG/KM. SNOW INCREASES
IN COVERAGE AND INTENSITY ON MONDAY AS ANOTHER SHORTWAVE TROUGH
MOVES ACROSS THE AREA FROM THE NORTHWEST. THE LEFT EXIT REGION OF
A 135 KT JET MOVES OVERHEAD EARLY IN THE DAY TO ENHANCE LIFT. THE
BULK OF THE MOISTURE REMAINS OVER THE NORTHERN AND CENTRAL
COLORADO MOUNTAINS...THOUGH SOME SNOW WILL MOVE INTO THE WESTERN
SAN JUANS DURING THE AFTERNOON.
SINCE MODELS WERE MORE PERSISTENT WITH THE SNOWFALL THROUGH THE
NEXT 24 HOURS ACCUMULATIONS ARE EXPECTED TO REACH ADVISORY LEVELS
ACROSS THE ELKHEAD...PARK AND GORE RANGES AS WELL AS PORTIONS OF
THE ELK RANGE. NAM INDICATED AS MUCH AS 12 INCHES IN THE HIGHER
MOUNTAINS WHILE GFS AND ECMWF WERE A BIT MORE UNDERSTATED. GIVEN
GUIDANCE OUTPUT WENT AHEAD WITH STORM TOTALS OF 6 TO 12 INCHES IN
THESE AREAS.
SNOW DECREASES AND BECOMES MORE SCATTERED IN COVERAGE MONDAY NIGHT
AS THE SECOND WAVE SHIFTS EAST OF THE AREA. CLOUDS AND
PRECIPITATION WILL MODERATE TEMPERATURES TONIGHT WITH MOST
LOCATIONS ABOVE NORMAL. CONVERSELY...HIGHS WILL BE COOLER DUE TO
THE INFLUX OF COOLER AIR AND CLOUD COVER. DECREASING CLOUDS
MONDAY NIGHT WILL LEAD TO BELOW NORMAL LOWS BY TUESDAY MORNING.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 300 PM MST SUN FEB 15 2015
A NORTH-NORTHWEST FLOW WILL PREVAIL OVER THE FORECAST AREA ON
TUE...THEN WILL WEAKEN SOMEWHAT ON WEDNESDAY. A WEAK DISTURBANCE
EMBEDDED IN THE FLOW WILL DROP INTO THE NORTHERN PLAINS ON
TUE...ON THE BACKSIDE OF THE LARGE LOW PRESSURE TROUGH ACROSS THE
NATION`S MID SECTION TO THE EAST COAST. THIS WILL BRUSH OUR
NORTHEAST CORNER...AND ALONG WITH NORTHWEST OROGRAPHICS WILL KEEP
A CHANCE OF SNOW ALONG THE NORTHERN DIVIDE MOUNTAINS INTO THE
AFTERNOON. BY EARLY EVENING ANY LINGERING SHOWERS WILL END AS THE
GRADIENT BEGINS TO RELAX...AND MOISTURE DIMINISHES. THEN ON WED
ANOTHER EMBEDDED WAVE WILL PASS TO OUR NORTHEAST. THIS ONE WILL
HAVE LESS EFFECT ON OUR AREA AS IT WILL BE FARTHER AWAY AS HIGH
PRESSURE BUILDS OVER THE WEST COAST. THEREFORE DO NOT EXPECT MUCH
MORE THAN INCREASED CLOUDS FOR A TIME OVER MAINLY OVER THE
NORTHEAST CORNER.
HIGH PRESSURE WILL PERSIST OVER THE WEST COAST THROUGH THE END OF
THE LONG TERM PERIOD AND BEYOND. ON THU AND FRI...A MORE RELAXED
NORTHWEST FLOW OVER OUR AREA AND WARMING TEMPERATURES ALOFT WILL
ALLOW SURFACE TEMPERATURES TO REBOUND. THEN BY LATE FRIDAY THE FLOW
WILL BECOME WESTERLY AS A DEVELOPING SHORTWAVE TROUGH APPROACHES
FROM THE NORTH. THIS TROUGH WILL BRING OUR NEXT CHANCE WINTRY
CONDITIONS TO THE AREA THIS WEEKEND. HOWEVER THERE CONTINUES TO
BE SIGNIFICANT DIFFERENCES IN THE MODELS. SO CONFIDENCE IS NOT
HIGH. STAY TUNED TO FUTURE FORECASTS AS THIS STORM SYSTEM EVOLVES.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 456 PM MST SUN FEB 15 2015
SCATTERED SNOW SHOWERS WILL CONTINUE ACROSS MUCH OF WESTERN
COLORADO THROUGH TONIGHT...WITH ACTIVITY INCREASING IN COVERAGE
DURING THE DAY ON MONDAY. EXPECT AREAS OF MVFR TO IFR CIGS AND
VSBYS THROUGH THE PERIOD WITH FREQUENT MOUNTAIN OBSCURATIONS.
TERMINAL SITES WILL REMAIN VFR FOR THE MOST PART...WITH THE
EXCEPTION OF KASE AND KEGE WHICH WILL SEE MORE FREQUENT DROPS IN
CIGS IN THIS NORTHWEST FLOW EVENT.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...WINTER WEATHER ADVISORY UNTIL 6 PM MST MONDAY FOR COZ004-010.
UT...NONE.
&&
$$
UPDATE...JDC
SHORT TERM...NL
LONG TERM...EH
AVIATION...JDC
AREA FORECAST DISCUSSION
NWS ALBANY NY
640 AM EST SAT FEB 14 2015
.SYNOPSIS...
A POWERFUL CLIPPER SYSTEM WILL IMPACT THE REGION TODAY WITH SNOW
ACROSS THE ENTIRE REGION. THIS STORM WILL RAPIDLY INTENSIFY OFF
THE NEW ENGLAND COAST TONIGHT. INCREASING WINDS AND DANGEROUS
WIND CHILLS ON THE BACK SIDE OF THIS INTENSE STORM WILL BE FELT
SUNDAY INTO SUNDAY NIGHT.
&&
.NEAR TERM /THROUGH TONIGHT/...
..WINTER WEATHER ADVISORY FOR SNOW AND BLOWING SNOW..
AS OF 630 AM EST...LIGHT SNOW WAS MAKING PROGRESS INTO EASTERN NY
WITH REPORTS OF VIRGA TO THE WEST OF ALBANY. LATEST 06Z GUIDANCE
AND HRRR CONTINUE TO SUGGEST THE SNOW TODAY WILL BE RATHER LIGHT.
MINOR UPDATES TO THE HOURLY GRIDS BASED ON OBSERVATIONS.
AS OF 300 AM EST...THIS MORNINGS H2O VAPOR LOOP DEPICTS A
POWERFUL SHORT WAVE CURRENTLY DIGGING/AMPLIFYING ACROSS THE STATE
OF WISCONSIN. AHEAD OF THIS FEATURE...A BROAD ISENTROPIC LIFT WARM
ADVECTION REGIME ALOFT COMBINING WITH UPPER LEVEL EXIT REGION
DYNAMICS WILL RESULT IN LIGHT SNOW OVERSPREAD THE ENTIRE CWFA
THIS MORNING. INITIALLY...DUE TO THE DRY COLUMN...THE INITIAL
BURST OF SNOW WILL LIKELY BE VIRGA. HOWEVER...THE COLUMN WILL
EVENTUALLY SATURATE FOR SNOW TO BEGIN LATER THIS MORNING FROM WEST
TO EAST. ISENTROPIC ANALYSIS ON THE 280K SURFACE REVEALS THE
CONTINUOUS LIFT ON THE SURFACE WITH SPECIFIC HUMIDITIES ON THE
SURFACE AVERAGING AROUND 1 G/KG. THIS WOULD SUGGEST THE SNOW WILL
GENERALLY BE LIGHT THROUGH THE DAY WITH THE UPSLOPE FAVORED
TERRAIN AREAS LIKELY SEEING A LITTLE ADDITIONAL BOOST. THE FLUFF
FACTOR FOR THE SNOW /SNOW RATIO/ WILL BE HIGHER THAN CLIMATOLOGY
WITH VALUES AROUND 15:1. THE FORECAST QPF FROM COORDINATION FROM
WPC YIELDS AROUND 0.10 SO GENERALLY 1-2 INCHES DURING THE DAYLIGHT
HOURS. AS FOR HIGH TEMPERATURES...TEENS TO LOWER 20S ARE EXPECTED.
TONIGHT...AS THE POTENT UPPER WAVE MOVES OFF THE MID-ATLANTIC/NEW
ENGLAND COAST THIS EVENING...EXPLOSIVE CYCLOGENESIS WILL
COMMENCE. THE CHALLENGE FOR OUR REGION IS IF/WHERE THE INVERTED
TROUGH AXIS DEVELOPS AND EVOLVING TROWAL/DEFORMATION. THE 00Z/06Z
NAM12 REMAINS CONSISTENT WITH THE INVERTED TROUGH AXIS SETTING UP
MAINLY TO THE SOUTH OF I90. 00Z GFS IS FURTHER NORTH WHICH WOULD
IMPACT THE I90 CORRIDOR AND THE 00Z ECMWF IS INBETWEEN. THE OTHER
COMPLICATED FACTOR TO THIS IS CROSS SECTIONS REVEAL A TROPOPAUSE
FOLD OCCURRING ACROSS EASTERN NY WHICH COULD CUT DOWN OUR SNOW
ACCUMULATIONS AS WELL. GIVEN THE UNCERTAINTY WHERE AND JUST HOW
INTENSE THIS INVERTED TROUGH AXIS WILL BE...WE WILL CONTINUE WITH
THE SNOW AND BLOWING SNOW ADVISORY THROUGH TONIGHT.
FURTHERMORE...BUFKIT PROFILES ACROSS THE REGION SUGGEST WITHIN
THIS BAND OF SNOW...THE MAX LIFT WILL OCCUR WITHIN THE FAVORED
DENDRITIC GROWTH ZONE WHERE SNOW RATES COULD BE MAXIMIZED. PER
COORDINATION WPC QPF VALUES...ANOTHER 1-4 INCHES ARE EXPECTED.
GIVEN THE TIME FRAME OF THIS SNOW EVENT...WE FELT WE WOULD NOT
EXCEED OUR 7 INCHES IN 12 HOURS NOR THE 9 INCHES IN 24 HOURS FOR
ANYTHING HIGHER THAN AN ADVISORY. THANKS FOR THE EXTENSIVE
COLLABORATION TO NEIGHBORING FORECAST OFFICES THIS MORNING.
WINDS WILL INCREASE OVERNIGHT AND WHERE SNOW HAS FALLEN ALONG WITH
PREVIOUS SNOW ON THE GROUND...CONSIDERABLE BLOWING SNOW IS
EXPECTED. POTENTIAL MIXING LAYER HEIGHTS SUGGEST WIND GUSTS WILL
BE WITHIN THE 20KT RANGE /FUNNELING DOWN THE HUDSON COULD INCREASE
THOSE MAGNITUDES FURTHER CLOSER TO 30 KTS/.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY/...
..WIND CHILL WARNINGS POSTED FOR THE ENTIRE REGION..
AS THE METEOROLOGICAL BOMB DEEPENS FURTHER IN THE GULF OF
MAINE...DEFORMATION AXIS IS FORECAST TO LINE UP ALONG OR JUST EAST
OF THE HUDSON RIVER SUNDAY MORNING. WE WILL HOLD ONTO THE ADVISORY
THROUGH THE MID MORNING HOURS WITH THE BEST POTENTIAL FOR
ADDITIONAL ACCUMULATING SNOW ALONG AND EAST OF I87. THE MAIN
HAZARD WILL BE THE INCREASE WINDS AND FALLING TEMPERATURES. MIXING
LAYER HEIGHTS SUGGEST WE TAP INTO THE 30KT RANGE ALONG WITH
FUNNELING INTO THE VALLEY LOCATIONS WILL RESULT IN ADDITIONAL
BLOWING SNOW. BUT THE FALLING TEMPERATURES COMBINING WITH THESE
WINDS WILL RESULT IN BITTERLY COLD...DANGEROUS...LIFE THREATING
WIND CHILLS! AFTER EXTENSIVE COORDINATION...WIND CHILL WARNINGS
WILL BE ISSUED FOR THE ENTIRE CWFA. TEMPERATURES SUNDAY NIGHT WILL
FALL WELL BELOW ZERO WITH WIND CHILLS APPROACHING 50 BELOW ZERO
INTO THE ADIRONDACK REGION WITH 25 TO 40 BELOW ZERO ELSEWHERE.
SKIES WILL LIKELY QUICKLY CLEAR SUNDAY EVENING AS WELL FURTHER
INCREASING THE POTENTIAL FOR THESE LOW TEMPERATURES.
SUBSIDENCE INCREASES QUICKLY OVERNIGHT INTO MONDAY MORNING AS
SURFACE HIGH OVER THE OHIO VALLEY AND LOWER GREAT LAKES BUILDS
INTO THE REGION. A GREAT DEAL OF SUNSHINE IS FORECAST MONDAY ALONG
WITH DIMINISHING WINDS AS THE WIND CHILL WARNING HEADLINE IS SET
TO EXPIRE AROUND NOON /MAY TRANSITION TO AN ADVISORY BUT WE WILL
MONITOR TRENDS AND ADJUST ACCORDINGLY/.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
TO START THE EXTENDED PERIOD...ANOTHER VERY COLD NIGHT IS EXPECTED
FOR MONDAY NIGHT. LUCKILY...WINDS WILL BECOMING LIGHT DURING THE
OVERNIGHT HOURS THANKS TO HIGH PRESSURE MOVING OVER THE AREA...SO
WIND CHILL WON/T BE A BIG FACTOR. STILL...OVERNIGHT LOWS ARE
EXPECTED TO BE BRUTAL OVER THE REGION...WITH MIN TEMPS BELOW ZERO
EVERYWHERE...WITH -10 TO -20 OVER THE HIGH TERRAIN.
THE HIGH PRESSURE AREA WILL SLIDE EASTWARD FOR TUESDAY MORNING
...BUT WILL REMAIN CLOSE ENOUGH TO THE AREA TO ALLOW FOR CONTINUED
DRY WEATHER THROUGH THE MORNING. TEMPS WILL CONTINUE TO BE BELOW
NORMAL...WITH HIGHS ONLY IN THE MID TEENS TO MID 20S. CLOUDS WILL
START TO INCREASE FOR TUESDAY AFTERNOON AND SOME LIGHT SNOWFALL MAY
BEGIN IN FAR SOUTHWESTERN AREAS BY THE LATE AFTN OR EARLY EVENING
HOURS. THIS WILL ULTIMATELY DEPEND ON THE TRACK OF A SOUTHERN STREAM
SFC LOW PRESSURE AREA MOVING UP THE EASTERN SEABOARD. WHILE SOME
RECENT MODEL GUIDANCE...INCLUDING THE 00Z ECMWF...SHOW THIS SYSTEM
REMAINING FAR ENOUGH SOUTH AND EAST TO HAVE LITTLE IMPACT ON THE
AREA...THERE STILL REMAINS SOME UNCERTAINTY. THE 00Z GFS AND MANY OF
THE 00Z GEFS MEMBERS CONTINUE TO SHOW AN IMPACT OF AT LEAST LIGHT TO
MODERATE SNOW BY LATE TUESDAY INTO TUESDAY NIGHT...AND ENDING
WEDNESDAY MORNING. WITH THIS UNCERTAINTY IN MIND...WILL CONTINUE
TO GO WITH CHC POPS FOR SNOW DURING THIS TIME PERIOD. TEMPS WILL
CONTINUE TO BE VERY COLD...WITH SINGLE DIGITS FOR TUESDAY
NIGHT...AND MID TEENS TO MID 20S ON WEDNESDAY.
BEHIND THIS STORM SYSTEM...ANOTHER BLAST OF FRIGID ARCTIC AIR LOOKS
TO MOVE TOWARDS THE REGION FOR THE LAKE WEEK PERIOD. SOME LAKE
EFFECT SNOW MAY IMPACT FAR NORTHWESTERN AREAS AS WELL...WITH SOME
FLURRIES POSSIBLE ELSEWHERE THANKS TO A DEEP AND COLD UPPER LEVEL
TROUGH OVER THE REGION. TEMPS ON WED/THURS NIGHTS WILL BE BELOW
ZERO FOR MOST LOCATIONS...WITH TEMPS CLOSING IN ON -20 ACROSS THE
ADIRONDACKS. HIGHS ON THURS/FRI ONLY LOOK TO REACH THE SINGLE
DIGITS TO LOW TEENS.
&&
.AVIATION /08Z SATURDAY THROUGH WEDNESDAY/... DURING THE MORNING
TODAY...BKN-OVC CIGS WILL CONTINUE TO LOWER AND THICKEN. WINDS WILL
BE LIGHT FROM A SOUTHERLY DIRECTION. MUCH OF THE MORNING WILL BE
DRY...ALTHOUGH A FEW VERY LIGHT FLURRIES OR AREAS OF LIGHT SNOW MAY
START TO MOVE TOWARDS THE TAF SITES TOWARDS THE LATE MORNING HOURS.
BASED ON THE LATEST HIRES NAM/HRRR GUIDANCE...LIGHT SNOWFALL LOOKS
TO EXPAND FROM WEST TO EAST ACROSS THE REGION DURING THE AFTERNOON
HOURS. ALTHOUGH SNOWFALL WILL BE LIGHT...EXPECT THIS STEADY SNOW TO
BEGIN AND DROP VSBYS TO IFR BY ABOUT 18-19Z FOR ALL TAF SITES. LIGHT
SNOW WILL CONTINUE THROUGH THE REMAINDER OF THE DAY...AND MAY BECOME
SOMEWHAT HEAVIER TOWARDS EVENING...SO WILL CONTINUE TO ALLOW FOR
LOWER VSBYS/CIGS TOWARDS EVENING AND INTO THE OVERNIGHT HOURS.
SOUTH WINDS WILL BE IN PLACE AT 5-10 KTS DURING THE DAY TODAY. WINDS
WILL ABRUPTLY SWITCH TO A N-NW DIRECTION LATE THIS EVENING...AS AN
ARCTIC COLD FRONT PASSES THROUGH THE REGION. WINDS WILL START TO
BECOME STRONGER AND GUSTIER BY LATE TONIGHT...WITH A FEW GUSTS TO
NEAR 25 KTS AT KALB LATE TONIGHT. SNOWFALL WILL CONTINUE THROUGH
MUCH OF SAT NIGHT...ESP AT KPSF...BUT WILL START TO LIGHTEN UP BY
LATE IN THE NIGHT...ALTHOUGH BLOWING SNOW IS EXPECTED FOR ALL SITES.
FLYING CONDITIONS MAY RETURN TO MVFR FOR MOST SITES BY THE LATE
NIGHT HOURS...ALTHOUGH THIS IS RATHER LOW CONFIDENCE FOR WHEN
EXACTLY THIS WILL OCCUR.
OUTLOOK...
SUN: MODERATE OPERATIONAL IMPACT. CHC SHSN...BLSN.
SUN NIGHT-MON NIGHT: NO OPERATIONAL IMPACT. NO SIG WEATHER.
TUE-WED: MODERATE OPERATIONAL IMPACT. CHC SN.
&&
.HYDROLOGY...
MUCH BELOW NORMAL TEMPERATURES WILL BE THE GENERAL RULE WHICH
WILL ALLOW ICE TO CONTINUE TO THICKEN ON RIVERS...STREAMS
CREEKS...LAKES AND OTHER BODIES OF WATER. SOME GAGES WILL
EXPERIENCE MORE ICE AFFECTS THROUGH THE WEEKEND.
A ROUND OF LIGHT TO MODERATE SNOWFALL TODAY INTO TONIGHT.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING
OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE
VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON
OUR WEBSITE.
&&
.CLIMATE...
GIVEN THE BITTERLY COLD TEMPERATURES ALOFT...WE LOOKED AT
CLIMATOLOGY FOR THE 850MB LEVEL. THE COLDEST EVER OBSERVED ON OUR
UPPER AIR SOUNDINGS WAS -30C. PER NCEP MODEL SUITE...THE LOWEST
VALUES AT UPPER AIR RELEASE TIMES /00Z/12Z/ ARE FORECAST TO BE
INTO THE NEGATIVE MID 20S C ON 00Z MON.
SURFACE TEMPERATURES...
RECORD LOW TEMPERATURES FOR MONDAY FEBRUARY 16TH:
LOCATIONTEMPYEAR
ALBANY-20F1943
GLENS FALLS-24F2004
POUGHKEEPSIE-3 F1963
BENNINGTON -13F2004
PITTSFIELD-26F1943
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...WINTER WEATHER ADVISORY FROM 10 AM THIS MORNING TO 10 AM EST
SUNDAY FOR CTZ001-013.
WIND CHILL WARNING FROM 10 AM SUNDAY TO NOON EST MONDAY FOR
CTZ001-013.
NY...WINTER WEATHER ADVISORY FROM 10 AM THIS MORNING TO 10 AM EST
SUNDAY FOR NYZ032-033-038>043-047>054-058>061-063>066-
082>084.
WIND CHILL WARNING FROM 10 AM SUNDAY TO NOON EST MONDAY FOR
NYZ032-033-038>043-047>054-058>061-063>066-082>084.
MA...WINTER WEATHER ADVISORY FROM 10 AM THIS MORNING TO 10 AM EST
SUNDAY FOR MAZ001-025.
WIND CHILL WARNING FROM 10 AM SUNDAY TO NOON EST MONDAY FOR
MAZ001-025.
VT...WINTER WEATHER ADVISORY FROM 10 AM THIS MORNING TO 10 AM EST
SUNDAY FOR VTZ013>015.
WIND CHILL WARNING FROM 10 AM SUNDAY TO NOON EST MONDAY FOR
VTZ013>015.
&&
$$
SYNOPSIS...GJM/BGM
NEAR TERM...BGM
SHORT TERM...GJM/BGM
LONG TERM...FRUGIS
AVIATION...FRUGIS
HYDROLOGY...BGM
CLIMATE...BGM
WWW.WEATHER.GOV/ALBANY
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
906 PM CST SUN FEB 15 2015
.SHORT TERM...
255 PM CST
THROUGH TONIGHT...
THE LAKE EFFECT SNOW BAND IS CONTINUING TO DIMINISH AS THE MAIN
BAND HAS BROKEN INTO TWO PIECES. THE DIFFICULT PART IS THE SOUTHERN
PIECE IS SITTING OVER SOUTHWEST LAKE MICHIGAN BRINGING LIGHT SNOW
AND FLURRIES TO COOK AND LAKE COUNTIES IN ILLINOIS. CONDITIONS ARE
BECOMING LESS AND LESS FAVORABLE FOR LAKE EFFECT SNOW AS CONVERGENCE
WEAKENS...AND NOT EXPECTING MUCH ADDITIONAL ACCUMULATION. MAY SEE A
FEW TENTHS ALONG THE IMMEDIATE LAKESHORE...BUT VERY LITTLE IF ANY
ADDITIONAL MEASURABLE SNOW AWAY FROM THE LAKE. SNOW SHOULD COME TO
AN END ACROSS THE CWA LATE THIS AFTERNOON INTO THE EARLY EVENING.
HIGH PRESSURE IS BUILDING IN OVERHEAD AND EXPECTING MID TO HIGH
LEVEL CLOUDS TO STICK AROUND OVERNIGHT. SATELLITE IMAGERY FEATURES
THICK CLOUD COVER STRETCHING BACK ACROSS THE EASTERN DAKOTAS AND THE
CENTRAL PLAINS. WINDS SLOWLY WEAKEN AND VEER TO SOUTHEAST OVERNIGHT
AS WELL LIMITING MIXING. GIVEN NEWER SNOW OVER MUCH OF THE
CWA...LOWERED OVERNIGHT MINS BY A DEGREE OR TWO...AND FOCUSED THE
MAJORITY OF LOWERING OVER FAR NORTHEAST IL AND NW INDIANA WHERE THE
SNOW IS THE FRESHEST. LOOKING AT LOWS VARYING FROM AROUND +5 SOUTH
OF I-80...0 TO +5 ALONG THE LAKE...AND THEN 0 TO -5 IN THE OUTLYING
AREAS. WITH WEAKENING WINDS...MIN WIND CHILLS WILL NOT BE AS BAD AS
LAST NIGHT WITH VALUES RANGING FROM -5 TO -15...AND THE COLDEST
AREAS WILL BE IN THE OUTLYING AREAS.
JEE
&&
.LONG TERM...
255 PM CST
MONDAY THROUGH SUNDAY...
QUITE AN ANOMALOUSLY COLD PATTERN FOR THE LATTER HALF OF FEBRUARY IS
FORECAST TO JUST KEEP REINFORCING ITSELF TO EVEN RECORD LEVELS THIS
WEEK. THE DEEP NORTHWEST FLOW DRIVING THIS COLD WILL BE UNSETTLED AS
WELL WITH SEVERAL CHANCES FOR MAINLY MINOR SNOW.
FOR PRESIDENTS DAY...THE LOCAL AREA WILL REMAIN NORTH OF A MAJOR
WINTER STORM TO IMPACT THE OZARKS UP THE OHIO RIVER VALLEY. HIGH
CLOUDS FROM THIS WILL LIKELY SPREAD OVER AT LEAST THE SOUTHERN
PORTION OF THE FORECAST AREA...BUT DRY SURFACE RIDGING SHOULD KEEP
PRECIP AT BAY. HIGHS LOOK TO BE AROUND 20.
A LOBE OF THE POLAR VORTEX WILL DROP SOUTHWARD TUESDAY WITH THE
COLDEST 500MB TEMPERATURES OF NEAR -50C PROJECTED OVER ONTARIO BY
WEDNESDAY. NUMEROUS VORTICITY MAXIMA ARE FORECAST ON THE WESTERLY
SIDE OF THIS DIGGING FEATURE. THE FIRST IS SEEN IN
GUIDANCE...INCLUDING HIGH-RES MEMBERS AVAILABLE...MOVING INTO THE
REGION ON MONDAY NIGHT. THE MORE PROMINENT ONE ARRIVES TUESDAY
NIGHT INTO WEDNESDAY MORNING ASSOCIATED WITH THE TROPOSPHERE FOLD
AND DEEPER LIFT AND SATURATION. HAVE BUMPED UP SNOW CHANCES FOR
THAT TUESDAY NIGHT PERIOD WHERE IT LOOKS LIKE THE SATURATION WILL
BETTER CORRELATE WITH THE SNOW GROWTH AREA. COULD SEE SOME MINOR
FLUFFY ACCUMULATION WITH THAT. CONTINUED THE LOWER CHANCES AND
FLURRY MENTION AROUND THIS PERIOD...FROM BASICALLY MONDAY NIGHT
THROUGH WEDNESDAY.
MODEL GUIDANCE IS IN SOUND AGREEMENT ON THE MAGNITUDE OF THE
ARCTIC AIR MASS COMING IN BEHIND THIS...WITH THE 12Z NORTH
AMERICAN ENSEMBLE FORECAST SYSTEM /NAEFS/ INDICATING RECORD COLD
IN THE LOWER TROPOSPHERE FOR MID-LATE FEBRUARY CENTERED OVER IL/IN
ON WEDNESDAY AND WEDNESDAY NIGHT. THE 925MB TEMPERATURES ARE
FORECAST IN THE -19C TO -24C RANGE BY TWO OF ITS KEY MEMBERS...THE
GFS AND GEM...AND THE EC ALSO IS IN THIS RANGE. THIS EQUATES TO
HIGHS IN THE SINGLE DIGITS WEDNESDAY AND THURSDAY AND LOWS BELOW
ZERO IN MOST PLACES...WITH SOME RECORDS POSSIBLE /SEE CLIMO
DISCUSSION BELOW/. A WIND CHILL ADVISORY WILL LIKELY BE NEEDED FOR
WEDNESDAY NIGHT IF THIS PATTERN FORECAST CONTINUES. AS THE WINDS
DIMINISH WITH THE RIDGE...NOW FORECAST THURSDAY NIGHT...THAT COULD
PRESENT LOWS IN THE NEGATIVE DOUBLE DIGITS IN THE COLD
SPOTS...ESPECIALLY IF A FRESH LIGHT COATING PRESENTS ITSELF
TUESDAY NIGHT/EARLY WEDNESDAY.
LOOKING AHEAD...LONG RANGE ENSEMBLE GUIDANCE INDICATES THE FLOW
ALOFT TO TURN MORE WESTERLY AS THE TROUGH PULLS AWAY. THERE IS
SOME NOISE FOR PRECIPITATION POTENTIAL IN THERE...WITH THE
STRONGEST QPF SIGNAL TO OUR SOUTH...BUT THIS IS A WAYS OUT. GIVEN
THE REINFORCING SHOTS OF COLD AIR...WOULD NOT BE OVERLY SURPRISED
TO SEE THIS REMAIN OR SHIFT SOUTH...SIMILAR TO THE SYSTEM
HAPPENING TOMORROW TO OUR SOUTH /WHICH FOUR-SIX DAYS AGO HAD BEEN
FORECAST MORE OVER OUR AREA/.
MTF
&&
.CLIMATE...
309 PM CST
WHILE THE COLDEST AIR ALOFT ARRIVES WEDNESDAY...THE COLDEST SURFACE
TEMPERATURES MAY RESULT ON THURSDAY FEBRUARY 19TH...WHICH RIGHT NOW
APPEARS COULD JEOPARDIZE SOME RECORDS...ESPECIALLY THE LOW MAXS.
FEB 19TH
RECORD LOW RECORD LOW MAX
CHICAGO -7 (1936) 9 (1936)
ROCKFORD -16 (1979) 7 (1959)
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 03Z...
* HIGH-END MVFR CIGS LINGERING THIS EVENING WITH A FEW FLURRIES.
RATZER
//DISCUSSION...UPDATED 00Z...
SURFACE HIGH PRESSURE DRIFTING ACROSS THE AREA THIS AFTERNOON AND
EARLY THIS EVENING...ALLOWING LIGHT WINDS TO GRADUALLY VEER FROM
EAST TO SOUTHEAST. THIS HAS RESULTED IN LIGHT LAKE EFFECT SNOW
SHOWERS PUSHING INLAND ACROSS ORD/MDW...THOUGH IT APPEARS
LINGERING LIGHT SNOW SHOWERS/FLURRIES WILL BE MUCH LIGHTER THAN
THE HEAVIER BANDS FROM THIS AFTERNOON. LOWEST CONDITIONS EXPECTED
TO BE HIGH-RANGE MVFR EARLY...WITH MAINLY JUST FLURRIES WITH NO
VIS RESTRICTION THROUGH MID-LATE EVENING. SKIES BECOME VFR BY LATE
EVENING/OVERNIGHT AND CONTINUE THROUGH MONDAY.
WINDS EXPECTED TO REMAIN LESS THAN 10 KT TONIGHT THROUGH MONDAY...
GENERALLY BECOMING SOUTH ON MONDAY THOUGH WITH SPEEDS AROUND 5 KT.
DETAILS OF DIRECTION AT ANY GIVEN HOUR A LITTLE TRICKY WITH LIGHT
GRADIENT AND WESTERN PERIPHERY OF WEAKENING HIGH PRESSURE RIDGE IN
THE VICINITY. WEAK SURFACE TROUGH APPROACHES MONDAY NIGHT...WITH
THE POTENTIAL FOR DEVELOPMENT OF MVFR CIGS AND SOME FLURRIES AFTER
MIDNIGHT...JUST PAST THE END OF THE CURRENT 30 HOUR ORD TAF
PERIOD.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 03Z...
* MEDIUM-HIGH IN TIMING IMPROVEMENT FROM MVFR CIGS TO VFR AND
FLURRIES ENDING.
* MEDIUM CONFIDENCE IN WIND DIRECTION DETAILS...HIGH CONFIDENCE IN
OVERALL WIND TREND.
RATZER
//OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z...
TUESDAY...CHANCE OF MORNING FLURRIES AND NIGHTTIME SNOW SHOWERS.
MVFR CIGS POSSIBLE. WEST-NORTHWEST WINDS.
WEDNESDAY...CHANCE OF FLURRIES. MVFR CIGS POSSIBLE. NORTHWEST
WINDS.
THURSDAY...MAINLY VFR. NORTHWEST WINDS.
FRIDAY...CHANCE OF SNOW ESPECIALLY FRIDAY NIGHT. MVFR/IFR POSSIBLE
LATE. SOUTH WINDS.
SATURDAY...CHANCE OF SNOW ESPECIALLY IN THE MORNING. MVFR
POSSIBLE. SOUTHWEST WINDS BECOMING NORTHWEST.
RATZER
&&
.MARINE...
240 PM CST
WILL LET THE SMALL CRAFT ADVISORY END AT 3PM AS EXPECTED. AS CLOUDS
THIN SEEING A LOT OF ICE ACROSS THE NORTH END OF THE LAKE AND MOST
OF THE NSH WATERS...ESPECIALLY ALONG THE SOUTHERN END OF THE LAKE.
HIGH PRESSURE IS SPREADING OVER THE LAKE NOW AND NORTHEAST TO EAST
WINDS WILL DIMINISH TO 5 TO 10 KT THIS EVENING. WINDS VEER TO SOUTH
MONDAY MORNING AND INCREASE TO 10 TO 20 KT AS THE NEXT TROUGH
APPROACHES FROM THE WEST. THE TROUGH AND ITS ASSOCIATED COLD FRONT
SWING OVER THE LAKE MONDAY NIGHT INTO TUESDAY WITH WINDS BECOMING
WEST ALONG THE FRONT. WINDS CONTINUE TO VEER TO NORTHWEST AND
INCREASE TO 15 TO 25 KT TUESDAY...WITH THE HIGHER SPEEDS OVER THE
SOUTHERN HALF OF THE LAKE. THE GRADIENT CONTINUES TO TIGHTEN BEHIND
THE TROUGH AS A LARGE HIGH BUILDS DOWN THE PLAINS TUESDAY NIGHT INTO
WEDNESDAY WITH NORTHWEST GALES EXPECTED OVER THE OPEN WATERS
WEDNESDAY INTO WEDNESDAY EVENING. WHILE GALES LOOK PROBABLE...IT IS
STILL TOO SOON TO ISSUE ANY GALE RELATED HEADLINE. IN ADDITION...A
SMALL CRAFT ADVISORY WILL LIKELY BE NEEDED TUESDAY NIGHT INTO
WEDNESDAY. A GALE HEADLINE MAY BE NEEDED FOR THE INDIANA
NEARSHORE WATERS WEDNESDAY. NORTHWEST WINDS SLOWLY DIMINISH
THROUGH THURSDAY NIGHT AS THE HIGH SPREADS OVER THE LAKE. WEST
WINDS THURSDAY NIGHT BACK TO SOUTH AND INCREASE TO 30 KT BY FRIDAY
NIGHT AS THE HIGH SHIFTS EAST. WINDS THEN DIMINISH SATURDAY AND
BEGIN TO TURN NORTH BY SATURDAY NIGHT.
JEE
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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[top]
Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
852 PM CST Sun Feb 15 2015
.UPDATE...
ISSUED AT 845 PM CST SUN FEB 15 2015
Snow has edged as far north as Jacksonville to just south of
Springfield and Decatur as of 8pm. The more intense but very
narrow band of snow associated with the 700-500 mb frontogenetic
forcing was located from just north of St.Louis east to just
south of Effingham with the Rapid Refresh basically keeping
the band of forcing over the same area through midnight before
slipping to the south during the early morning hours. The latest
00z NAM-WRF not indicating much of a change with respect to the
location of the best forcing and greater snow totals through Mon
afternoon, which still looks to be along and south of Interstate
70 with a sharp drop-off in snow accumulations as you head north.
Current forecast looking good at this point with only some timing
adjustments to the snow in southeast Illinois early this evening
and some tweaks to the early evening temperature trends. Should
have an update out by 900 pm.
&&
.SHORT TERM...(Tonight)
ISSUED AT 315 PM CST SUN FEB 15 2015
Developing winter storm will begin to impact parts of the KILX CWA
tonight, with accumulating snow expected south of the I-72
corridor. Vigorous short-wave trough evident on 20z/2pm water vapor
imagery dropping southeastward through Utah will eject into the
Plains tonight, creating an area of enhanced lift/forcing and
eventually wintry precip. 18z NAM continues to show a band of 700mb
frontogenetical forcing developing across north-central Missouri
into south-central Illinois this evening. Strongest forcing appears
to be setting up along/south of a Saint Louis to Evansville line
overnight into Monday morning. Airmass is initially quite dry, so
precip will be slow to start. Upstream obs across Missouri show
thickening/lowering clouds, but no precip reaching the ground as of
yet. High-res models have been consistently showing light snow
developing across Missouri between 21z and 00z, then further east
into Illinois after 00z. Due to a persistent dry easterly flow
ahead of the system, there will be a sharp cut-off on the northern
end of the precip area. Previous model runs had shifted the snow a
bit further northward: however, both the 12z and 18z guidance seems
to have settled on a Rushville...to Lincoln...to Paris line as the
northernmost extent of the precip. Robust lift will be confined to
locations further south, generally along/south of the I-70
corridor. Have therefore gone with categorical PoPs there,
decreasing to just slight chance near I-72 and completely dry
further north across the remainder of the area. Nighttime
accumulations will range from 1 to 2 inches along/south of a
Jacksonville...to Mattoon...to Marshall line, with as much as 3 to 4
inches south of an Effingham to Robinson line. Additional
accumulations will occur Monday morning before the system departs.
&&
.LONG TERM...(Monday through Sunday)
ISSUED AT 315 PM CST SUN FEB 15 2015
Isentropic lift continuing into southeast Illinois through the
morning hours Monday while strong frontogenetical forcing continues
and an upper level shortwave approaches via the Rocky Mountain area
for the afternoon. This will keep persistent precipitation into the
afternoon before subsidence behind the shortwave begins to diminish
precipitation from west to east Monday afternoon and evening.
Time-height plots over the area show that a favorable dendritic
growth zone will be in place for much of this event meaning that the
snow should be fairly light and fluffy, resulting in deep
accumulations given the precipitation amounts. As a result,
storm total accumulations of 6-8 inches can be expected along and
south of highway 50, while lesser amounts are expected to the
north, with accumulating snow of 1-2 inches potentially as far
north as Springfield. A winter storm warning continues in the
central Illinois forecast area for Effingham to Crawford counties
south to Clay through Lawrence counties until 6 p.m., while a
winter weather advisory continues for the row of counties to the
north. The trickiest part of this forecast is that with the
surface low tracking by to the south along with the heaviest
precipitation, a strong gradient in precipitation amounts will be
in place through the southern half of the forecast area resulting
in some uncertainty in exact forecast amounts depending on slight
variations in the storm track.
Once the Monday system passes by, a deep upper level trough will
situate over the central and eastern U.S. for the remainder of the
week, and a widespread arctic air mass will remain coincident with
this feature, while reinforcing waves of arctic air continue to move
through central Illinois. A couple of weak upper-level disturbances
may bring some snow flurries Tuesday to Wednesday. Highs should
reach the 20s and upper teens Monday and Tuesday, then very cold air
will arrive for Wednesday and Thursday with highs in the upper
single digits and teens. Wind chills around -15 F are expected
Wednesday morning in the northern half of the state, spreading all
the way in to southeast IL by Thursday morning, potentially yielding
the lowest wind chill readings of the winter so far in southeast IL.
The deep trough moves east for Friday through the weekend allowing
temperatures to become less unusually cold. The next weather system
is progged by most models to move mainly south of the area next
weekend, although uncertainty with the track indicates a chance this
system will bring precipitation to central Illinois Friday night
through Sunday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
ISSUED AT 535 PM CST SUN FEB 15 2015
VFR conditions expected across our I-74 TAF sites while MVFR
cigs in light snow will prevail later this evening for SPI and
DEC. Latest radar indicating a developing band of snow to our
south with surface reports now indicating snow reaching the
ground over parts of north central Missouri and tracking
east. It still appears SPI and DEC will be on the northern
fringe of the snow tonight with our northern TAF sites staying
out of any snowfall with this system. Rather sharp cutoff to
the VFR and MVFR cat cigs with this system with the latest
HRRR and RUC models now suggesting more low VFR cigs for
our southern TAF sites. Not going to make any changes with
the current idea for MVFR cigs for SPI and DEC with SPI the
first to see the snow early this evening.
The snow should begin to shift south of SPI and DEC around the
12-14z time frame Monday as the system starts to pull away from
our area with VFR conditions in all areas by late morning thru
the afternoon. Surface winds will be east to northeast at 7 to 12
kts tonight and then will back into a more northerly direction on
Monday with again wind speeds on the light side, generally around
10 kts or less.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY until 6 PM CST Monday FOR ILZ052-061>063.
WINTER STORM WARNING until 6 PM CST Monday FOR ILZ066>068-
071>073.
&&
$$
UPDATE...Smith
SHORT TERM...Barnes
LONG TERM...Onton
AVIATION...Smith
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
551 PM CST SUN FEB 15 2015
.SHORT TERM...
255 PM CST
THROUGH TONIGHT...
THE LAKE EFFECT SNOW BAND IS CONTINUING TO DIMINISH AS THE MAIN
BAND HAS BROKEN INTO TWO PIECES. THE DIFFICULT PART IS THE SOUTHERN
PIECE IS SITTING OVER SOUTHWEST LAKE MICHIGAN BRINGING LIGHT SNOW
AND FLURRIES TO COOK AND LAKE COUNTIES IN ILLINOIS. CONDITIONS ARE
BECOMING LESS AND LESS FAVORABLE FOR LAKE EFFECT SNOW AS CONVERGENCE
WEAKENS...AND NOT EXPECTING MUCH ADDITIONAL ACCUMULATION. MAY SEE A
FEW TENTHS ALONG THE IMMEDIATE LAKESHORE...BUT VERY LITTLE IF ANY
ADDITIONAL MEASURABLE SNOW AWAY FROM THE LAKE. SNOW SHOULD COME TO
AN END ACROSS THE CWA LATE THIS AFTERNOON INTO THE EARLY EVENING.
HIGH PRESSURE IS BUILDING IN OVERHEAD AND EXPECTING MID TO HIGH
LEVEL CLOUDS TO STICK AROUND OVERNIGHT. SATELLITE IMAGERY FEATURES
THICK CLOUD COVER STRETCHING BACK ACROSS THE EASTERN DAKOTAS AND THE
CENTRAL PLAINS. WINDS SLOWLY WEAKEN AND VEER TO SOUTHEAST OVERNIGHT
AS WELL LIMITING MIXING. GIVEN NEWER SNOW OVER MUCH OF THE
CWA...LOWERED OVERNIGHT MINS BY A DEGREE OR TWO...AND FOCUSED THE
MAJORITY OF LOWERING OVER FAR NORTHEAST IL AND NW INDIANA WHERE THE
SNOW IS THE FRESHEST. LOOKING AT LOWS VARYING FROM AROUND +5 SOUTH
OF I-80...0 TO +5 ALONG THE LAKE...AND THEN 0 TO -5 IN THE OUTLYING
AREAS. WITH WEAKENING WINDS...MIN WIND CHILLS WILL NOT BE AS BAD AS
LAST NIGHT WITH VALUES RANGING FROM -5 TO -15...AND THE COLDEST
AREAS WILL BE IN THE OUTLYING AREAS.
JEE
&&
.LONG TERM...
255 PM CST
MONDAY THROUGH SUNDAY...
QUITE AN ANOMALOUSLY COLD PATTERN FOR THE LATTER HALF OF FEBRUARY IS
FORECAST TO JUST KEEP REINFORCING ITSELF TO EVEN RECORD LEVELS THIS
WEEK. THE DEEP NORTHWEST FLOW DRIVING THIS COLD WILL BE UNSETTLED AS
WELL WITH SEVERAL CHANCES FOR MAINLY MINOR SNOW.
FOR PRESIDENTS DAY...THE LOCAL AREA WILL REMAIN NORTH OF A MAJOR
WINTER STORM TO IMPACT THE OZARKS UP THE OHIO RIVER VALLEY. HIGH
CLOUDS FROM THIS WILL LIKELY SPREAD OVER AT LEAST THE SOUTHERN
PORTION OF THE FORECAST AREA...BUT DRY SURFACE RIDGING SHOULD KEEP
PRECIP AT BAY. HIGHS LOOK TO BE AROUND 20.
A LOBE OF THE POLAR VORTEX WILL DROP SOUTHWARD TUESDAY WITH THE
COLDEST 500MB TEMPERATURES OF NEAR -50C PROJECTED OVER ONTARIO BY
WEDNESDAY. NUMEROUS VORTICITY MAXIMA ARE FORECAST ON THE WESTERLY
SIDE OF THIS DIGGING FEATURE. THE FIRST IS SEEN IN
GUIDANCE...INCLUDING HIGH-RES MEMBERS AVAILABLE...MOVING INTO THE
REGION ON MONDAY NIGHT. THE MORE PROMINENT ONE ARRIVES TUESDAY
NIGHT INTO WEDNESDAY MORNING ASSOCIATED WITH THE TROPOSPHERE FOLD
AND DEEPER LIFT AND SATURATION. HAVE BUMPED UP SNOW CHANCES FOR
THAT TUESDAY NIGHT PERIOD WHERE IT LOOKS LIKE THE SATURATION WILL
BETTER CORRELATE WITH THE SNOW GROWTH AREA. COULD SEE SOME MINOR
FLUFFY ACCUMULATION WITH THAT. CONTINUED THE LOWER CHANCES AND
FLURRY MENTION AROUND THIS PERIOD...FROM BASICALLY MONDAY NIGHT
THROUGH WEDNESDAY.
MODEL GUIDANCE IS IN SOUND AGREEMENT ON THE MAGNITUDE OF THE
ARCTIC AIR MASS COMING IN BEHIND THIS...WITH THE 12Z NORTH
AMERICAN ENSEMBLE FORECAST SYSTEM /NAEFS/ INDICATING RECORD COLD
IN THE LOWER TROPOSPHERE FOR MID-LATE FEBRUARY CENTERED OVER IL/IN
ON WEDNESDAY AND WEDNESDAY NIGHT. THE 925MB TEMPERATURES ARE
FORECAST IN THE -19C TO -24C RANGE BY TWO OF ITS KEY MEMBERS...THE
GFS AND GEM...AND THE EC ALSO IS IN THIS RANGE. THIS EQUATES TO
HIGHS IN THE SINGLE DIGITS WEDNESDAY AND THURSDAY AND LOWS BELOW
ZERO IN MOST PLACES...WITH SOME RECORDS POSSIBLE /SEE CLIMO
DISCUSSION BELOW/. A WIND CHILL ADVISORY WILL LIKELY BE NEEDED FOR
WEDNESDAY NIGHT IF THIS PATTERN FORECAST CONTINUES. AS THE WINDS
DIMINISH WITH THE RIDGE...NOW FORECAST THURSDAY NIGHT...THAT COULD
PRESENT LOWS IN THE NEGATIVE DOUBLE DIGITS IN THE COLD
SPOTS...ESPECIALLY IF A FRESH LIGHT COATING PRESENTS ITSELF
TUESDAY NIGHT/EARLY WEDNESDAY.
LOOKING AHEAD...LONG RANGE ENSEMBLE GUIDANCE INDICATES THE FLOW
ALOFT TO TURN MORE WESTERLY AS THE TROUGH PULLS AWAY. THERE IS
SOME NOISE FOR PRECIPITATION POTENTIAL IN THERE...WITH THE
STRONGEST QPF SIGNAL TO OUR SOUTH...BUT THIS IS A WAYS OUT. GIVEN
THE REINFORCING SHOTS OF COLD AIR...WOULD NOT BE OVERLY SURPRISED
TO SEE THIS REMAIN OR SHIFT SOUTH...SIMILAR TO THE SYSTEM
HAPPENING TOMORROW TO OUR SOUTH /WHICH FOUR-SIX DAYS AGO HAD BEEN
FORECAST MORE OVER OUR AREA/.
MTF
&&
.CLIMATE...
309 PM CST
WHILE THE COLDEST AIR ALOFT ARRIVES WEDNESDAY...THE COLDEST SURFACE
TEMPERATURES MAY RESULT ON THURSDAY FEBRUARY 19TH...WHICH RIGHT NOW
APPEARS COULD JEOPARDIZE SOME RECORDS...ESPECIALLY THE LOW MAXS.
FEB 19TH
RECORD LOW RECORD LOW MAX
CHICAGO -7 (1936) 9 (1936)
ROCKFORD -16 (1979) 7 (1959)
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 00Z...
* DIMINISHING LIGHT LAKE EFFECT SNOW/FLURRIES ENDING THIS EVENING.
ANY LINGERING MVFR CIG/VIS DISSIPATING EARLY.
RATZER
//DISCUSSION...UPDATED 00Z...
SURFACE HIGH PRESSURE DRIFTING ACROSS THE AREA THIS AFTERNOON AND
EARLY THIS EVENING...ALLOWING LIGHT WINDS TO GRADUALLY VEER FROM
EAST TO SOUTHEAST. THIS HAS RESULTING IN LIGHT LAKE EFFECT SNOW
SHOWERS PUSHING INLAND ACROSS ORD/MDW...THOUGH IT APPEARS
LINGERING LIGHT SNOW SHOWERS/FLURRIES WILL BE MUCH LIGHTER THAN
THE HEAVIER BANDS FROM THIS AFTERNOON. LOWEST CONDITIONS EXPECTED
TO BE HIGH-RANGE MVFR EARLY...WITH MAINLY JUST FLURRIES WITH NO
VIS RESTRICTION THROUGH MID-LATE EVENING. SKIES BECOME VFR BY LATE
EVENING/OVERNIGHT AND CONTINUE THROUGH MONDAY.
WINDS EXPECTED TO REMAIN LESS THAN 10 KT TONIGHT THROUGH MONDAY...
GENERALLY BECOMING SOUTH ON MONDAY THOUGH WITH SPEEDS AROUND 5 KT.
DETAILS OF DIRECTION AT ANY GIVEN HOUR A LITTLE TRICKY WITH LIGHT
GRADIENT AND WESTERN PERIPHERY OF WEAKENING HIGH PRESSURE RIDGE IN
THE VICINITY. WEAK SURFACE TROUGH APPROACHES MONDAY NIGHT...WITH
THE POTENTIAL FOR DEVELOPMENT OF MVFR CIGS AND SOME FLURRIES AFTER
MIDNIGHT...JUST PAST THE END OF THE CURRENT 30 HOUR ORD TAF
PERIOD.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 00Z...
* MEDIUM-HIGH IN TIMING ENDING OF FLURRIES THIS EVENING. HIGH
CONFIDENCE THAT ANY ADDITIONAL LINGERING -SHSN SHOULD ONLY
PRODUCE MVFR OR HIGHER CONDITIONS.
* MEDIUM CONFIDENCE IN WIND DIRECTION DETAILS...HIGH CONFIDENCE IN
OVERALL WIND TREND.
RATZER
//OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z...
TUESDAY...CHANCE OF MORNING FLURRIES AND NIGHTTIME SNOW SHOWERS.
MVFR CIGS POSSIBLE. WEST-NORTHWEST WINDS.
WEDNESDAY...CHANCE OF FLURRIES. MVFR CIGS POSSIBLE. NORTHWEST
WINDS.
THURSDAY...MAINLY VFR. NORTHWEST WINDS.
FRIDAY...CHANCE OF SNOW ESPECIALLY FRIDAY NIGHT. MVFR/IFR POSSIBLE
LATE. SOUTH WINDS.
SATURDAY...CHANCE OF SNOW ESPECIALLY IN THE MORNING. MVFR
POSSIBLE. SOUTHWEST WINDS BECOMING NORTHWEST.
RATZER
&&
.MARINE...
240 PM CST
WILL LET THE SMALL CRAFT ADVISORY END AT 3PM AS EXPECTED. AS CLOUDS
THIN SEEING A LOT OF ICE ACROSS THE NORTH END OF THE LAKE AND MOST
OF THE NSH WATERS...ESPECIALLY ALONG THE SOUTHERN END OF THE LAKE.
HIGH PRESSURE IS SPREADING OVER THE LAKE NOW AND NORTHEAST TO EAST
WINDS WILL DIMINISH TO 5 TO 10 KT THIS EVENING. WINDS VEER TO SOUTH
MONDAY MORNING AND INCREASE TO 10 TO 20 KT AS THE NEXT TROUGH
APPROACHES FROM THE WEST. THE TROUGH AND ITS ASSOCIATED COLD FRONT
SWING OVER THE LAKE MONDAY NIGHT INTO TUESDAY WITH WINDS BECOMING
WEST ALONG THE FRONT. WINDS CONTINUE TO VEER TO NORTHWEST AND
INCREASE TO 15 TO 25 KT TUESDAY...WITH THE HIGHER SPEEDS OVER THE
SOUTHERN HALF OF THE LAKE. THE GRADIENT CONTINUES TO TIGHTEN BEHIND
THE TROUGH AS A LARGE HIGH BUILDS DOWN THE PLAINS TUESDAY NIGHT INTO
WEDNESDAY WITH NORTHWEST GALES EXPECTED OVER THE OPEN WATERS
WEDNESDAY INTO WEDNESDAY EVENING. WHILE GALES LOOK PROBABLE...IT IS
STILL TOO SOON TO ISSUE ANY GALE RELATED HEADLINE. IN ADDITION...A
SMALL CRAFT ADVISORY WILL LIKELY BE NEEDED TUESDAY NIGHT INTO
WEDNESDAY. A GALE HEADLINE MAY BE NEEDED FOR THE INDIANA
NEARSHORE WATERS WEDNESDAY. NORTHWEST WINDS SLOWLY DIMINISH
THROUGH THURSDAY NIGHT AS THE HIGH SPREADS OVER THE LAKE. WEST
WINDS THURSDAY NIGHT BACK TO SOUTH AND INCREASE TO 30 KT BY FRIDAY
NIGHT AS THE HIGH SHIFTS EAST. WINDS THEN DIMINISH SATURDAY AND
BEGIN TO TURN NORTH BY SATURDAY NIGHT.
JEE
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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
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Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
540 PM CST Sun Feb 15 2015
.SHORT TERM...(Tonight)
ISSUED AT 315 PM CST SUN FEB 15 2015
Developing winter storm will begin to impact parts of the KILX CWA
tonight, with accumulating snow expected south of the I-72
corridor. Vigorous short-wave trough evident on 20z/2pm water vapor
imagery dropping southeastward through Utah will eject into the
Plains tonight, creating an area of enhanced lift/forcing and
eventually wintry precip. 18z NAM continues to show a band of 700mb
frontogenetical forcing developing across north-central Missouri
into south-central Illinois this evening. Strongest forcing appears
to be setting up along/south of a Saint Louis to Evansville line
overnight into Monday morning. Airmass is initially quite dry, so
precip will be slow to start. Upstream obs across Missouri show
thickening/lowering clouds, but no precip reaching the ground as of
yet. High-res models have been consistently showing light snow
developing across Missouri between 21z and 00z, then further east
into Illinois after 00z. Due to a persistent dry easterly flow
ahead of the system, there will be a sharp cut-off on the northern
end of the precip area. Previous model runs had shifted the snow a
bit further northward: however, both the 12z and 18z guidance seems
to have settled on a Rushville...to Lincoln...to Paris line as the
northernmost extent of the precip. Robust lift will be confined to
locations further south, generally along/south of the I-70
corridor. Have therefore gone with categorical PoPs there,
decreasing to just slight chance near I-72 and completely dry
further north across the remainder of the area. Nighttime
accumulations will range from 1 to 2 inches along/south of a
Jacksonville...to Mattoon...to Marshall line, with as much as 3 to 4
inches south of an Effingham to Robinson line. Additional
accumulations will occur Monday morning before the system departs.
&&
.LONG TERM...(Monday through Sunday)
ISSUED AT 315 PM CST SUN FEB 15 2015
Isentropic lift continuing into southeast Illinois through the
morning hours Monday while strong frontogenetical forcing continues
and an upper level shortwave approaches via the Rocky Mountain area
for the afternoon. This will keep persistent precipitation into the
afternoon before subsidence behind the shortwave begins to diminish
precipitation from west to east Monday afternoon and evening.
Time-height plots over the area show that a favorable dendritic
growth zone will be in place for much of this event meaning that the
snow should be fairly light and fluffy, resulting in deep
accumulations given the precipitation amounts. As a result,
storm total accumulations of 6-8 inches can be expected along and
south of highway 50, while lesser amounts are expected to the
north, with accumulating snow of 1-2 inches potentially as far
north as Springfield. A winter storm warning continues in the
central Illinois forecast area for Effingham to Crawford counties
south to Clay through Lawrence counties until 6 p.m., while a
winter weather advisory continues for the row of counties to the
north. The trickiest part of this forecast is that with the
surface low tracking by to the south along with the heaviest
precipitation, a strong gradient in precipitation amounts will be
in place through the southern half of the forecast area resulting
in some uncertainty in exact forecast amounts depending on slight
variations in the storm track.
Once the Monday system passes by, a deep upper level trough will
situate over the central and eastern U.S. for the remainder of the
week, and a widespread arctic air mass will remain coincident with
this feature, while reinforcing waves of arctic air continue to move
through central Illinois. A couple of weak upper-level disturbances
may bring some snow flurries Tuesday to Wednesday. Highs should
reach the 20s and upper teens Monday and Tuesday, then very cold air
will arrive for Wednesday and Thursday with highs in the upper
single digits and teens. Wind chills around -15 F are expected
Wednesday morning in the northern half of the state, spreading all
the way in to southeast IL by Thursday morning, potentially yielding
the lowest wind chill readings of the winter so far in southeast IL.
The deep trough moves east for Friday through the weekend allowing
temperatures to become less unusually cold. The next weather system
is progged by most models to move mainly south of the area next
weekend, although uncertainty with the track indicates a chance this
system will bring precipitation to central Illinois Friday night
through Sunday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
ISSUED AT 535 PM CST SUN FEB 15 2015
VFR conditions expected across our I-74 TAF sites while MVFR
cigs in light snow will prevail later this evening for SPI and
DEC. Latest radar indicating a developing band of snow to our
south with surface reports now indicating snow reaching the
ground over parts of north central Missouri and tracking
east. It still appears SPI and DEC will be on the northern
fringe of the snow tonight with our northern TAF sites staying
out of any snowfall with this system. Rather sharp cutoff to
the VFR and MVFR cat cigs with this system with the latest
HRRR and RUC models now suggesting more low VFR cigs for
our southern TAF sites. Not going to make any changes with
the current idea for MVFR cigs for SPI and DEC with SPI the
first to see the snow early this evening.
The snow should begin to shift south of SPI and DEC around the
12-14z time frame Monday as the system starts to pull away from
our area with VFR conditions in all areas by late morning thru
the afternoon. Surface winds will be east to northeast at 7 to 12
kts tonight and then will back into a more northerly direction on
Monday with again wind speeds on the light side, generally around
10 kts or less.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY until 6 PM CST Monday FOR ILZ052-061>063.
WINTER STORM WARNING until 6 PM CST Monday FOR ILZ066>068-
071>073.
&&
$$
SHORT TERM...Barnes
LONG TERM...Onton
AVIATION...Smith
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1202 PM CST SAT FEB 14 2015
.SHORT TERM...
332 AM CST
THROUGH SUNDAY...
NO CHANGES TO GOING HEADLINES FOR TODAY. HOWEVER...WE HAVE ISSUED A
WIND CHILL ADVISORY FOR THE AREA FOR TONIGHT.
MAIN WEATHER FORECAST CONCERNS CONTINUE TO FOCUS ON THE STRONG
ARCTIC PUSH TODAY...WITH DANGEROUS WIND CHILLS TONIGHT...AND ALSO
THE LAKE EFFECT SNOW SHOWERS...PARTICULARLY ACROSS NORTHWESTERN
INDIANA LATER TODAY AND TONIGHT...THEN OVER NORTHEASTERN ILLINOIS ON
SUNDAY.
WATER VAPOR IMAGERY EARLY THIS MORNING SHOWS THE MAIN UPPER LEVEL PV
ANOMALY RAPIDLY DIGGING SOUTHWARD OVER NORTHERN WISCONSIN.
MEANWHILE...THE ASSOCIATED SURFACE LOW CONTINUES TO DEEPEN TO NEAR
1000 MB OVER THE UPPER GREAT LAKES REGION...WITH THE MAIN SURFACE
COLD FRONT RIGHT ON OUR DOOR STEP ACROSS FAR NORTHERN ILLINOIS.
TEMPERATURES AHEAD OF THIS FRONT AT STILL QUITE MILD IN THE UPPER
20S TO NEAR 30. HOWEVER...THE BOTTOM WILL FALL OUT IN A HURRY HERE
OVER THE NEXT FEW HOURS...AS TEMPERATURES QUICKLY TUMBLE INTO THE
TEENS AFTER DAYBREAK TODAY...AND CONTINUE TO FALL INTO THE SINGLE
DIGITS THIS AFTERNOON.
LOWER LEVEL LAPS RATES WILL STEEP UP FOLLOWING THE FRONTAL
PASSAGE...AND THIS SHOULD ALLOW FOR THE DEVELOPMENT OF SOME ISOLATED
TO SCATTERED SNOW SHOWERS ACROSS THE REGION THIS MORNING.
HOWEVER...IT APPEARS THE BETTER FOCUS FOR SNOW SHOWERS...OUTSIDE OF
LAKE EFFECT...WILL OCCUR ACROSS MY SOUTHERN AREAS THIS MORNING AS THE
LOWER LEVEL BAROCLINIC ZONE CONTINUES TO STRENGTHEN...SETTING UP A
BAND OF STRONG FGEN ACROSS CENTRAL ILLINOIS THIS MORNING. THIS WILL
BE A SHORT LIVED FEATURE...HOWEVER...SO SNOW AMOUNTS AREA-WIDE WILL
LIKELY REMAIN A HALF IN OR LESS.
NORTHERLY WINDS WILL INCREASE QUICKLY THIS MORNING...AND THE
COMBINATION OF VERY STRONG COLD AIR ADVECTION...AND RAPID PRESSURE
RISES...COULD RESULT IN A PERIOD OF NEAR WIND ADVISORY CRITERIA WINDS
(GUSTS TO 45 MPH)...PARTICULARLY ACROSS EASTERN ILLINOIS AND
NORTHWESTERN INDIANA LATER THIS MORNING AND INTO THE AFTERNOON.
MODEL SOUNDINGS ACROSS THESE AREAS INDICATE MEAN MIXING LAYER WINDS
AROUND 36 KT...WITH AROUND 40 TO 42 KT AT THE TOP OF MIXING LAYER.
STRONGLY FORCED COLD AIR ADVECTION REGIMES SUCH AS WHAT IS EXPECTED
THIS MORNING...CAN SET UP SITUATIONS WHEN SOME OF THE HIGHEST WINDS
IN THE MIXING LAYER MIX DOWN TO THE SURFACE AS WIND GUSTS...AT LEAST
FOR SHORT PERIODS OF TIME. IF THIS DOES OCCUR...THERE COULD BE A
SHORT PERIOD WITH WIND GUSTS TOPPING 45 MPH TODAY. OVERALL IT
APPEARS THE STRONGEST WIND POTENTIAL WILL BE NEAR THE LAKE IN
NORTHWESTERN INDIANA...AND THIS AREA IS CURRENTLY COVERED BY EITHER
A WIND ADVISORY OR A WINTER STORM WARNING. WE THOUGHT ABOUT POSSIBLY
EXPANDING THE WIND ADVISORY TO INCLUDE ALL OF NORTHWESTERN INDIANA
AND SOME OF EASTERN ILLINOIS. HOWEVER...AFTER COLLABORATING WITH
NEIGHBORING OFFICES...WE HAVE DECIDED NOT TO EXPAND THE CURRENT WIND
ADVISORY.
THE LAKE EFFECT POTENTIAL IS REALLY UNCHANGED FROM PREVIOUS
FORECASTS. IT STILL APPEARS THAT THE MAIN SETUP TODAY WILL FAVOR
NORTHEASTERN PORTER COUNTY INDIANA AND POINTS EAST...AS STRONG
NORTHWESTERN BOUNDARY LAYER WINDS KEEP THE BETTER LOWER LEVEL
CONVERGENCE MORE BROAD...AND MAINLY TO THE EAST OF MY AREA. THIS
COULD SUPPORT MULTIPLE BANDS OF LAKE EFFECT SNOW SHOWERS. HOWEVER...IT
STILL DOES APPEAR THAT AS A STOUT SURFACE BUILDS EASTWARD ACROSS THE
UPPER MIDWEST BY THIS EVENING...THAT THE BOUNDARY LAYER WINDS OVER
LAKE MICHIGAN WILL BECOME MORE NORTHERLY...AND GRADUALLY EASE IN
MAGNITUDE OVERNIGHT TONIGHT. THIS COULD SET UP MORE OF A SINGLE
CONVERGENT WESTWARD MOVING BAND OF LAKE EFFECT SNOW SHOWERS OVER
SOUTHERN LAKE MICHIGAN TONIGHT...AND BETTER ACCUMULATION POTENTIAL
FOR MY NORTHWESTERN INDIANA COUNTIES NEAR THE LAKE. INVERSION
HEIGHTS SHOULD BE ON A DECLINE DURING THIS TIME. HOWEVER...GIVEN THE
COLD AIRMASS...THE CLOUDS SHOULD BE COLD ENOUGH TO SUPPORT ICE
CRYSTALS. TOTAL SNOWFALL AMOUNTS SHOULD NOT GET TO OUT OF HAND...AS
THE BAND SHOULD BECOME PROGRESSIVE. HOWEVER...AMOUNTS IN EXCESS OF 6
INCHES ARE STILL POSSIBLE ACROSS PORTIONS OF THE WARNING AREA.
ADDITIONALLY...WITH THE STRONG WINDS TODAY AND THIS EVENING...BLOWING
SNOW AND WHITE OUT CONDITIONS WILL BE A CONCERN AT TIMES.
WINDS OVER THE LAKE WILL CONTINUE TO BACK MORE NORTHEASTERLY FOR A
PERIOD ON SUNDAY...SO SOME LIGHT LAKE EFFECT SNOW SHOWERS APPEAR
LIKELY ACROSS THE CHICAGO AREA OF NORTHEASTERN ILLINOIS.
HOWEVER...THE BAND OF SNOW SHOWERS LOOKS TO BECOME A LESS ORGANIZED
BY SUNDAY. THEREFORE...IT STILL APPEARS THAT ACCUMULATIONS ACROSS
THE CHICAGO AREA WILL GENERALLY REMAIN ON THE LIGHT SIDE. THE WINDS
ARE EXPECTED SHIFT OFFSHORE BY EARLY SUNDAY EVENING...SO ANY
LINGERING SHOWERS WILL END BY THIS TIME.
A WIND CHILL ADVISORY WILL GO INTO EFFECT FOR THE REGION THIS
EVENING. THE COMBINATION OF LINGERING BREEZY WINDS AND TEMPERATURES
FALLING INTO NEGATIVE TERRITORY THROUGH THE EVENING WILL SET UP WIND
CHILLS OF 20 BELOW TO 30 BELOW...WITH THE COLDEST EXPECTED ACROSS
NORTH CENTRAL ILLINOIS. THIS ADVISORY WILL BE IN EFFECT UNTIL MID
MORNING ON SUNDAY. TEMPERATURES LOOK TO ONLY TOP OUT NEAR 10 ABOVE IN
MOST AREAS ON SUNDAY...BUT WITH LIGHT WINDS DURING THE DAY...WIND
CHILLS SHOULD NOT BE AN ISSUE.
KJB
&&
.LONG TERM...
332 AM CST
SUNDAY NIGHT THROUGH FRIDAY...
THE WEATHER PATTERN OVER THE COUNTRY WILL CONTINUE TO FAVOR
PERIODS OF COLD ARCTIC OUTBREAKS OVER THE EASTERN HALF OF THE
CONUS NEXT WEEK. STRONG HIGH LATITUDE UPPER RIDGING OVER THE EASTERN
PACIFIC/WESTERN NORTH AMERICA WILL SET THE STAGE FOR A FAIRLY
PROLONGED PERIOD OF MUCH BELOW NORMAL HEIGHTS AND TEMPERATURES
ACROSS MUCH OF EASTERN NORTH AMERICA. OUTSIDE OF LAKE EFFECT
SNOWS...NO BIG SNOW EVENTS ARE EXPECTED THROUGH THE PERIOD.
HOWEVER...SOME MINOR SNOW SYSTEMS COULD IMPACT THE AREA WITHIN THE
CYCLONIC UPPER LEVEL FLOW PATTERN. A REINFORCING SHOT OF COLD
ARCTIC AIR LOOKS TO SET UP OVER THE AREA BY MID WEEK...AND THIS
AIRMASS COULD EVEN BE A BIT COLDER THAN THE SHORT TERM COLD
EXPECTED. THIS COULD RESULT IN HIGH TEMPERATURES ONLY IN THE
SINGLE DIGITS IN MOST AREAS ON WEDNESDAY.
KJB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* NORTHWEST TO NORTH-NORTHWEST WINDS GUSTING TO AROUND 35 KT
THROUGH EARLY AFTERNOON...DIMINISHING THROUGH THE EVENING AND
OVERNIGHT.
* SCATTERED SNOW SHOWERS THROUGH EARLY AFTERNOON...OCNL MVFR
CIG/VIS POSSIBLE.
* VARIABLE MVFR TO VFR CIGS...IMPROVING TO PREVAILING VFR THIS
AFTERNOON.
* SNOW CHANCES ONCE AGAIN SUNDAY WITH MVFR CIGS AND IFR VSBY
POSSIBLE.
KREIN
//DISCUSSION...UPDATED 18Z...
A STRONG COLD FRONT HAS PUSHED SOUTH INTO THE OHIO VALLEY WITH
STRONG HIGH PRESSURE BUILDING OVER THE NRN PLAINS AND UPPER
MISSISSIPPI VALLEY. ALSO LOW PRESSURE ASSOCIATED WITH THE COLD
FRONT IS MOVING THROUGH THE EASTERN GREAT LAKES. THE HIGH IS
ASSOCIATED WITH A VERY COLD AIRMASS AND WITH THE CENTER OF THE
HIGH STILL OVER MANITOBA...A STRONG NORTHWESTERLY PRESSURE
GRADIENT HAS SET UP ACROSS THE REGION. THE COMBINATION OF THE
STRONG GRADIENT AND STRONG COLD ADVECTION HAS BROUGHT STRONG WIND
GUSTS OF 35-40KT ACROSS NRN IL/IN. A STRONG UPPER LEVEL IMPULSE
AND A JET STREAK CROSSING CENTRAL IL/IN HAVE HELP FOCUS THE
DEVELOPMENT OF BANDS OF SNOW SHOWERS ACROSS THE REGION...WITH
OCCASIONAL BURSTS OF IFR VIS AND LOWER END MVFR CIGS. THROUGH THE
AFTERNOON...EXPECT A DOWNWARD TRENDS IN WINDS SPEEDS AND GUSTS
WHILE DIRECTION REMAINS GENERALLY NNWLY. THE COVERAGE OF SNOW
SHOWERS SHOULD ALSO DIMINISH WITH TIME THROUGH THE AFTERNOON AS
DRIER AIR FILTERS ACROSS THE REGION...BUT RESIDUAL STRONG WINDS
SHOULD CONTINUE TO GENERATE AREAS OF BLOWING SNOW WHICH MAY REDUCE
VIS TO 3-5SM. AS THE CENTER OF THE HIGH BUILDS ACROSS THE UPPER
GREAT LAKES TONIGHT...WITH A RIDGE AXIS EXTENDING SOUTH AND
TRACKING MISSISSIPPI VALLEY...WINDS SHOULD DIMINISH TO LESS THAN
10KT BY EARLY TOMORROW MORNING. AS THE RIDGE AXIS ACROSS LAKE
MICHIGAN TOMORROW MORNING...EXPECT A PLUME OF LAKE EFFECT SNOW TO
DEVELOP OVER SOUTHERN LAKE MICHIGAN...WHICH THE HIGH RES MODEL
GUIDANCE CONSISTENTLY SUGGESTING SHOULD MOVE WEST INTO NERN
IL...POSSIBLY AFFECTING GYY/ORD/MDW. SHOULD THE LAKE EFFECT PLUME
MOVE INLAND FAR ENOUGH...IFR CONDITIONS WILL BE LIKELY AT THESE
TERMINALS. AT THIS POINT...DO NOT EXPECT THE LAKE EFFECT SNOW TO
MOVE FAR ENOUGH WEST TO IMPACT DPA AND RFD SHOULD BE WELL REMOVED
FROM ANY LAKE INFLUENCE AND CONDITIONS SHOULD BE VFR WITH LIGHT
WINDS THROUGH THE DAY. OTHER THAN THE CHANCES FOR LAKE EFFECT SNOW
SHOWERS TOMORROW MORNING...CONDITIONS SHOULD BE QUIET AT THE
EASTERN TERMINALS BY TOMORROW AFTERNOON WITH LIGHT SELY WINDS AND
UNRESTRICTED CIG/VIS.
KREIN
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH CONFIDENCE IN WIND TRENDS.
* HIGH CONFIDENCE IN SCATTERED SNOW SHOWERS THROUGH EARLY THIS
AFTERNOON. LOW CONFIDENCE IN ANY IMPACTS AT THE TERMINALS AS
ACTIVITY IS ON A DIMINISHING TREND.
* HIGH CONFIDENCE IN GENERAL CIG/VIS TREND...LOWER CONFIDENCE IN
THE DURATION OF ANY REDUCED CIG/VIS EARLY THIS AFTERNOON AND
TOMORROW MORNING DUE TO RESIDUAL SNOW SHOWERS THIS AFTERNOON AND
LAKE EFFECT SNOW SHOWERS TOMORROW MORNING.
* HIGH CONFIDENCE IN SNOW FORECAST FOR SUNDAY...BUT ONLY MEDIUM
CONFIDENCE IN TIMING AND DURATION.
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT...MVFR POSSIBLE.
MONDAY...MVFR. SLIGHT CHANCE OF SNOW. SOUTHWEST WINDS.
TUESDAY THROUGH THURSDAY...PERIODS OF MVFR POSSIBLE. WEST TO
NORTHWEST WINDS.
FRIDAY...VFR. SOUTHWEST WINDS.
MDB
&&
.MARINE...
317 AM CST
LOW PRESSURE JUST EAST OF LAKE SUPERIOR OR OVER NORTHERN GEORGIAN
BAY WILL MOVE SOUTHEAST TO THE SOUTHERN NEW ENGLAND COAST INTO
TONIGHT WHILE STRENGTHENING. VERY STRONG HIGH PRESSURE OVER THE
CANADIAN PRAIRIES WILL SETTLE SOUTHWARD INTO THE MID AND UPPER
MISSISSIPPI RIVER VALLEY AND WESTERN GREAT LAKES INTO SUNDAY.
WINDS ARE SHIFTING FROM SOUTHWEST TO NORTHWEST AS A STRONG COLD
FRONT PUSHES SOUTHWARD DOWN THE LAKE THIS MORNING. WITH THE LOW
DEEPENING AND THE VERY STRONG HIGH ALLOWING FOR AN INCREASING
PRESSURE GRADIENT AND THEN COMBINING WITH THE STRONG COLD
ADVECTION BEHIND THE FRONT...WINDS WILL QUICKLY RAMP UP EARLY THIS
MORNING. PEAK WINDS ARE EXPECTED FROM MID/LATE MORNING THROUGH THE
AFTERNOON BEFORE SLOWLY EASING. 50 KT GUSTS LOOK LIKELY ACROSS
MUCH OF THE LAKE...ESPECIALLY THE SOUTHERN TWO-THIRDS...FROM LATE
MORNING THROUGH THE AFTERNOON. WITH ROUGHLY 6 HOURS OF GALES
EXPECTED PRIOR TO THE STORM FORCE WINDS...HAVE OPTED TO KEEP A
GALE WARNING IN EFFECT OUT THE GATE UNTIL A STORM WARNING TAKES
OVER AT 15Z FOR THE OPEN WATERS. HAVE THEN KEPT THE EXISTING GALE
WARNING FROM MID EVENING INTO THE OVERNIGHT. WILL KEEP NEARSHORE
AREAS IN A GALE...WITH STORM FORCE WINDS MORE LIKELY TO THE
EAST...BUT WILL MENTION POSSIBLE STORM FORCE GUSTS FOR THE INDIANA
WATERS. BETWEEN THE WINDS AND WAVES HEAVY FREEZING SPRAY WILL
OCCUR AND HAVE MAINTAINED THE HEAVY FREEZING SPRAY WARNING.
THE HIGH MOVES ACROSS THE GREAT LAKES SUNDAY THROUGH MONDAY WHICH
WILL LEAD TO WINDS WHICH WILL TURN EASTERLY SUNDAY AND SUNDAY NIGHT
BEFORE SOUTHWEST WINDS TAKE OVER AHEAD OF THE NEXT SERIES OF LOW
PRESSURE SYSTEMS. THIS WILL MEAN ANOTHER PERIOD OF NORTHERLY WINDS
AS WELL AS VERY COLD TEMPERATURES BY WEDNESDAY. HIGH PRESSURE IS
THEN EXPECTED TO RETURN LATE NEXT WEEK.
MDB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WIND CHILL ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-
ILZ023-ILZ032-ILZ033-ILZ039...8 PM SATURDAY TO 9 AM SUNDAY.
IN...WIND ADVISORY...INZ001 UNTIL 6 PM SATURDAY.
WIND CHILL ADVISORY...INZ001-INZ010-INZ011-INZ019...8 PM
SATURDAY TO 9 AM SUNDAY.
WINTER STORM WARNING...INZ002 UNTIL 9 AM SUNDAY.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...9 PM SATURDAY TO 3 AM
SUNDAY.
HEAVY FREEZING SPRAY WARNING...LMZ080-LMZ261-LMZ362-LMZ364-
LMZ366-LMZ563-LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-
LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-
LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 3 AM SUNDAY.
STORM WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 PM SATURDAY.
GALE WARNING...NEARSHORE WATERS UNTIL 3
AM SUNDAY.
&&
$$
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FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1200 PM CST Sat Feb 14 2015
.UPDATE...
ISSUED AT 1049 AM CST SAT FEB 14 2015
Cold front has quickly dropped southward into the Ohio River
Valley this morning, taking much of the snow with it. 16z/10am
radar mosaic shows light snow lingering across the SE KILX CWA,
mainly along/south of an Effingham to Robinson line. The snow will
persist for another 1 to 2 hours, then will exit the area by
midday, leaving behind accumulations between one half and one inch.
Further north, clearing line is already working its way into
north-central Illinois and will rapidly sweep southward this
afternoon. Meanwhile, quite a bit of diurnal Cu has developed
across the Great Lakes into northern Illinois and will brush the
N/NE CWA through mid-afternoon before gradually dissipating later
in the day. May even see a few flurries, especially along/northeast
of a Lacon to Paris line. Big story today will be the windy and
sharply colder conditions. Latest obs show winds gusting to
between 35 and 40mph across the board. Greatest 3-hr pressure
rises of around 10mb are currently analyzed across Iowa into
Wisconsin and these are progged to slide southeastward into the
area early this afternoon. May see a few gusts of 40-45mph at
times, but will generally stay near or just below Wind Advisory
criteria. Temps have already reached daily maxes and are on their
way down, with readings expected to range from the single digits
north to around 20 degrees far south by late afternoon.
&&
.SHORT TERM...(Today)
ISSUED AT 330 AM CST SAT FEB 14 2015
The Arctic cold front has reached southeastern Iowa and it should
reach near the Illinois river around sunrise, then progress across
the remainder of our counties this morning. The 00z models continue
to show a band of snow showers along and behind the front, with the
higher accumulations concentrating on the southwestern half of our
forecast area this morning. The upstream radar and satellite images
seem to be correlating well with the RAP area of 700-850mb
frontogenetic forcing. The forecast soundings still show limited
deep layer moisture, with disjointed saturated layers during the
morning. Dry air will likely limit the snowfall potential of the
system, but narrow bands of enhanced lift could linger in localized
areas as the mid-level forcing advances across C IL. Isolated bands
of up to 1 inch can not be ruled out in those cases, but most areas
should stay below a half inch, with some areas just seeing trace
amounts. Pinpointing exact locations of the bands is difficult even
this close to the event, and ongoing evaluation of correlating RAP
F-gen with radar and satellite will be needed through the morning to
keep any localized bands of heavier snow covered in the gridded
forecast.
Have advanced a band of likely PoPs this morning across our
southwest areas, but also included an hour or two of likely PoPs as
far north as Lincoln to Paris. Chance PoPs were included for at
least a couple hours in all of our northern counties at some point
this morning when the F-gen and moisture best coincide.
Temps will be steady or falling through the day. High temps for this
calendar day most likely will occur early this morning ahead of the
cold front. Strong pressure rises this afternoon will cause blustery
northwest winds to develop, with sustained speeds of 20-30 mph and a
few gusts around 40 mph. Wind chills by late afternoon will dip
below zero across all of our area, with -10 to -15F north of Peoria
already by 00z/6pm.
&&
.LONG TERM...(Tonight through Friday)
ISSUED AT 330 AM CST SAT FEB 14 2015
Vigorous short wave to track into the mid Atlantic states this
evening and deepen a very strong surface low off the New England
coast tonight. This to bring yet another blizzard to coastal New
England including Boston tonight into Sunday. But for IL the main
story will be the bitter cold temperatures and wind chills. Will
issue a wind chill advisory tonight starting at 6 pm and go until 9
am Sunday for areas from Canton to Lincoln to Terre Haute northeast
where wind chills get down to 15-20 below zero. Lows overnight range
from zero to 5 below from Lincoln and Champaign north to 0 to 5
above south from I-72 south.
Strong 1046 mb arctic high pressure over nw Manitoba to weaken to
1035 mb as it drifts into the Great Lakes region Sunday afternoon.
Meanwhile a weak northern stream short wave will dive se from the
Pacific Northwest into the MO valley Sunday evening and bring chance
of light snow and flurries to areas sw of Lincoln later Sunday
afternoon into Sunday night. Snow accumulations of a dusting to up
to a half inch sw third of CWA possible with better chances of light
snow accumulations over sw and southern IL. Cold highs Sunday in the
teens. Lows Sunday night around 5F from I-74 ne to around 10F sw
CWA.
Dry conditions prevail Monday and Monday night with surface ridge
over IL with partly to mostly cloudy skies. Highs in mid to upper
20s which is still 10-15 degrees below normal for mid February.
00Z models continue to keep a stronger southern stream wx system
south of central IL Tue with surface low over southern MS river
valley. Have just chance of flurries far sw/southern counties on
Tue. Another surge of arctic air arrives Tue night through Wed night
with wind chills reaching near or a bit colder than 15 below over
northern counties. Dry conditions prevail rest of the week as temps
modify into low to mid 30s Friday afternoon.
The Climate Prediction Center (CPC) Day 8-14 Temperature Outlook for
Feb 21-27th has IL in a greater than 80% chance of below normal
temperatures, and this covers the Great Lakes region including IN/OH.
So winter`s grip looks to continue across the region the rest of the
month as upper level trof generally prevails over eastern North America
east of the Rockies.
&&
.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
ISSUED AT 1200 PM CST SAT FEB 14 2015
Strong northwesterly winds gusting to between 25 and 35kt will
persist through mid-afternoon before slowly beginning to diminish
by this evening. Pressure gradient will remain tight enough to
support continued gusts to around 20kt at the eastern terminals
through around 04-05z, before winds subside to 12kt or less
overnight. Diurnal cloud cover associated with a vigorous
upper-level disturbance over the Great Lakes will skirt across the
N/NE KILX CWA this afternoon. VFR ceilings of around 3500ft can be
expected at times for the I-74 TAF sites, with mostly clear skies
further southwest at both KSPI and KDEC. Once these clouds
dissipate later this afternoon, mostly clear conditions will
prevail until mid-level clouds begin to increase from the west
after 09z.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY from 6 PM this evening to 9 AM CST Sunday
FOR ILZ027>031-036>038-041>046-055-057.
&&
$$
UPDATE...Barnes
SHORT TERM...Shimon
LONG TERM...07
AVIATION...Barnes
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
752 AM CST SAT FEB 14 2015
.SHORT TERM...
332 AM CST
THROUGH SUNDAY...
NO CHANGES TO GOING HEADLINES FOR TODAY. HOWEVER...WE HAVE ISSUED A
WIND CHILL ADVISORY FOR THE AREA FOR TONIGHT.
MAIN WEATHER FORECAST CONCERNS CONTINUE TO FOCUS ON THE STRONG
ARCTIC PUSH TODAY...WITH DANGEROUS WIND CHILLS TONIGHT...AND ALSO
THE LAKE EFFECT SNOW SHOWERS...PARTICULARLY ACROSS NORTHWESTERN
INDIANA LATER TODAY AND TONIGHT...THEN OVER NORTHEASTERN ILLINOIS ON
SUNDAY.
WATER VAPOR IMAGERY EARLY THIS MORNING SHOWS THE MAIN UPPER LEVEL PV
ANOMALY RAPIDLY DIGGING SOUTHWARD OVER NORTHERN WISCONSIN.
MEANWHILE...THE ASSOCIATED SURFACE LOW CONTINUES TO DEEPEN TO NEAR
1000 MB OVER THE UPPER GREAT LAKES REGION...WITH THE MAIN SURFACE
COLD FRONT RIGHT ON OUR DOOR STEP ACROSS FAR NORTHERN ILLINOIS.
TEMPERATURES AHEAD OF THIS FRONT AT STILL QUITE MILD IN THE UPPER
20S TO NEAR 30. HOWEVER...THE BOTTOM WILL FALL OUT IN A HURRY HERE
OVER THE NEXT FEW HOURS...AS TEMPERATURES QUICKLY TUMBLE INTO THE
TEENS AFTER DAYBREAK TODAY...AND CONTINUE TO FALL INTO THE SINGLE
DIGITS THIS AFTERNOON.
LOWER LEVEL LAPS RATES WILL STEEP UP FOLLOWING THE FRONTAL
PASSAGE...AND THIS SHOULD ALLOW FOR THE DEVELOPMENT OF SOME ISOLATED
TO SCATTERED SNOW SHOWERS ACROSS THE REGION THIS MORNING.
HOWEVER...IT APPEARS THE BETTER FOCUS FOR SNOW SHOWERS...OUTSIDE OF
LAKE EFFECT...WILL OCCUR ACROSS MY SOUTHERN AREAS THIS MORNING AS THE
LOWER LEVEL BAROCLINIC ZONE CONTINUES TO STRENGTHEN...SETTING UP A
BAND OF STRONG FGEN ACROSS CENTRAL ILLINOIS THIS MORNING. THIS WILL
BE A SHORT LIVED FEATURE...HOWEVER...SO SNOW AMOUNTS AREA-WIDE WILL
LIKELY REMAIN A HALF IN OR LESS.
NORTHERLY WINDS WILL INCREASE QUICKLY THIS MORNING...AND THE
COMBINATION OF VERY STRONG COLD AIR ADVECTION...AND RAPID PRESSURE
RISES...COULD RESULT IN A PERIOD OF NEAR WIND ADVISORY CRITERIA WINDS
(GUSTS TO 45 MPH)...PARTICULARLY ACROSS EASTERN ILLINOIS AND
NORTHWESTERN INDIANA LATER THIS MORNING AND INTO THE AFTERNOON.
MODEL SOUNDINGS ACROSS THESE AREAS INDICATE MEAN MIXING LAYER WINDS
AROUND 36 KT...WITH AROUND 40 TO 42 KT AT THE TOP OF MIXING LAYER.
STRONGLY FORCED COLD AIR ADVECTION REGIMES SUCH AS WHAT IS EXPECTED
THIS MORNING...CAN SET UP SITUATIONS WHEN SOME OF THE HIGHEST WINDS
IN THE MIXING LAYER MIX DOWN TO THE SURFACE AS WIND GUSTS...AT LEAST
FOR SHORT PERIODS OF TIME. IF THIS DOES OCCUR...THERE COULD BE A
SHORT PERIOD WITH WIND GUSTS TOPPING 45 MPH TODAY. OVERALL IT
APPEARS THE STRONGEST WIND POTENTIAL WILL BE NEAR THE LAKE IN
NORTHWESTERN INDIANA...AND THIS AREA IS CURRENTLY COVERED BY EITHER
A WIND ADVISORY OR A WINTER STORM WARNING. WE THOUGHT ABOUT POSSIBLY
EXPANDING THE WIND ADVISORY TO INCLUDE ALL OF NORTHWESTERN INDIANA
AND SOME OF EASTERN ILLINOIS. HOWEVER...AFTER COLLABORATING WITH
NEIGHBORING OFFICES...WE HAVE DECIDED NOT TO EXPAND THE CURRENT WIND
ADVISORY.
THE LAKE EFFECT POTENTIAL IS REALLY UNCHANGED FROM PREVIOUS
FORECASTS. IT STILL APPEARS THAT THE MAIN SETUP TODAY WILL FAVOR
NORTHEASTERN PORTER COUNTY INDIANA AND POINTS EAST...AS STRONG
NORTHWESTERN BOUNDARY LAYER WINDS KEEP THE BETTER LOWER LEVEL
CONVERGENCE MORE BROAD...AND MAINLY TO THE EAST OF MY AREA. THIS
COULD SUPPORT MULTIPLE BANDS OF LAKE EFFECT SNOW SHOWERS. HOWEVER...IT
STILL DOES APPEAR THAT AS A STOUT SURFACE BUILDS EASTWARD ACROSS THE
UPPER MIDWEST BY THIS EVENING...THAT THE BOUNDARY LAYER WINDS OVER
LAKE MICHIGAN WILL BECOME MORE NORTHERLY...AND GRADUALLY EASE IN
MAGNITUDE OVERNIGHT TONIGHT. THIS COULD SET UP MORE OF A SINGLE
CONVERGENT WESTWARD MOVING BAND OF LAKE EFFECT SNOW SHOWERS OVER
SOUTHERN LAKE MICHIGAN TONIGHT...AND BETTER ACCUMULATION POTENTIAL
FOR MY NORTHWESTERN INDIANA COUNTIES NEAR THE LAKE. INVERSION
HEIGHTS SHOULD BE ON A DECLINE DURING THIS TIME. HOWEVER...GIVEN THE
COLD AIRMASS...THE CLOUDS SHOULD BE COLD ENOUGH TO SUPPORT ICE
CRYSTALS. TOTAL SNOWFALL AMOUNTS SHOULD NOT GET TO OUT OF HAND...AS
THE BAND SHOULD BECOME PROGRESSIVE. HOWEVER...AMOUNTS IN EXCESS OF 6
INCHES ARE STILL POSSIBLE ACROSS PORTIONS OF THE WARNING AREA.
ADDITIONALLY...WITH THE STRONG WINDS TODAY AND THIS EVENING...BLOWING
SNOW AND WHITE OUT CONDITIONS WILL BE A CONCERN AT TIMES.
WINDS OVER THE LAKE WILL CONTINUE TO BACK MORE NORTHEASTERLY FOR A
PERIOD ON SUNDAY...SO SOME LIGHT LAKE EFFECT SNOW SHOWERS APPEAR
LIKELY ACROSS THE CHICAGO AREA OF NORTHEASTERN ILLINOIS.
HOWEVER...THE BAND OF SNOW SHOWERS LOOKS TO BECOME A LESS ORGANIZED
BY SUNDAY. THEREFORE...IT STILL APPEARS THAT ACCUMULATIONS ACROSS
THE CHICAGO AREA WILL GENERALLY REMAIN ON THE LIGHT SIDE. THE WINDS
ARE EXPECTED SHIFT OFFSHORE BY EARLY SUNDAY EVENING...SO ANY
LINGERING SHOWERS WILL END BY THIS TIME.
A WIND CHILL ADVISORY WILL GO INTO EFFECT FOR THE REGION THIS
EVENING. THE COMBINATION OF LINGERING BREEZY WINDS AND TEMPERATURES
FALLING INTO NEGATIVE TERRITORY THROUGH THE EVENING WILL SET UP WIND
CHILLS OF 20 BELOW TO 30 BELOW...WITH THE COLDEST EXPECTED ACROSS
NORTH CENTRAL ILLINOIS. THIS ADVISORY WILL BE IN EFFECT UNTIL MID
MORNING ON SUNDAY. TEMPERATURES LOOK TO ONLY TOP OUT NEAR 10 ABOVE IN
MOST AREAS ON SUNDAY...BUT WITH LIGHT WINDS DURING THE DAY...WIND
CHILLS SHOULD NOT BE AN ISSUE.
KJB
&&
.LONG TERM...
332 AM CST
SUNDAY NIGHT THROUGH FRIDAY...
THE WEATHER PATTERN OVER THE COUNTRY WILL CONTINUE TO FAVOR
PERIODS OF COLD ARCTIC OUTBREAKS OVER THE EASTERN HALF OF THE
CONUS NEXT WEEK. STRONG HIGH LATITUDE UPPER RIDGING OVER THE EASTERN
PACIFIC/WESTERN NORTH AMERICA WILL SET THE STAGE FOR A FAIRLY
PROLONGED PERIOD OF MUCH BELOW NORMAL HEIGHTS AND TEMPERATURES
ACROSS MUCH OF EASTERN NORTH AMERICA. OUTSIDE OF LAKE EFFECT
SNOWS...NO BIG SNOW EVENTS ARE EXPECTED THROUGH THE PERIOD.
HOWEVER...SOME MINOR SNOW SYSTEMS COULD IMPACT THE AREA WITHIN THE
CYCLONIC UPPER LEVEL FLOW PATTERN. A REINFORCING SHOT OF COLD
ARCTIC AIR LOOKS TO SET UP OVER THE AREA BY MID WEEK...AND THIS
AIRMASS COULD EVEN BE A BIT COLDER THAN THE SHORT TERM COLD
EXPECTED. THIS COULD RESULT IN HIGH TEMPERATURES ONLY IN THE
SINGLE DIGITS IN MOST AREAS ON WEDNESDAY.
KJB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* NORTHWEST TO NORTH-NORTHWEST WINDS GUSTING TO AROUND 35 KT
LATE MORNING THROUGH AFTERNOON.
* SCATTERED SNOW BANDS BRINGING INTERMITTENT PRIODS OF IFR VSBY.
POSSIBLE BRIEF PERIODS OF 1/2SM OR LESS...BUT TOO BRIEF TO CARRY
IN THE TEMPO GROUP.
* VARIABLE MVFR CIGS SCATTERING THIS AFTERNOON.
* SNOW CHANCES ONCE AGAIN SUNDAY WITH MVFR CIGS AND IFR VSBY
POSSIBLE.
KREIN
//DISCUSSION...UPDATED 12Z...
A COLD FRONTAL BOUNDARY IS CROSSING THE TERMINALS EARLY THIS
MORNING AND BRINGING A SHIFT TO NORTHWEST WINDS. STRONG HIGH
PRESSURE WILL MOVE IN FROM THE NORTH AS LOW PRESSURE MOVES FROM
SOUTHERN ONTARIO TO SOUTHERN NEW ENGLAND. THE INCREASING PRESSURE
GRADIENT BETWEEN THESE SYSTEMS AND AN INFLUX OF COLD AIR WILL
RESULT IN INTENSIFYING WINDS THROUGH THE MORNING. EXPECT THAT
GUSTS TO AROUND 30 KT WILL QUICKLY DEVELOP THIS MORNING WITH 35 KT
GUSTS POSSIBLE BY MIDDAY. GYY MAY SEE GUSTS AROUND 40 KT
CONSIDERING THEIR PROXIMITY TO THE LAKE. CIGS ARE MAINLY MVFR BUT
AM SEEING QUITE A BIT OF VARIABILITY IN BASE HEIGHT WITH SOME
AREAS OF VFR MIXED IN.
A PASSING UPPER TROUGH IS AIDING IN SNOW SHOWER DEVELOPMENT TO THE
NORTHWEST WHICH IS SPREADING INTO THE LOCAL TERMINALS. COVERAGE
WILL REMAIN LOW BUT THE MORE INTENSE SNOW SHOWERS WILL LIKELY
PRODUCE BRIEF PERIODS OF IFR VSBY AND LEAD TO SOME MINOR
ACCUMULATION. THE BULK OF THIS ACTIVITY WILL EXIT BY MIDDAY. LAKE
EFFECT SNOW WILL TAKE OVER INTO NORTHWEST INDIANA INTO THE
AFTERNOON AND PERSIST OVERNIGHT. AT THIS POINT THE BULK OF THE
ACTIVITY SHOULD REMAIN EAST OF GYY BUT WILL EVENTUALLY PIVOT
WESTWARD SUNDAY MORNING SO A PERIOD OF SNOW SHOWERS MAY OCCUR
THERE AT THAT TIME. THE BAND LOOKS TO PIVOT FURTHER WEST THROUGH
MIDDAY SUNDAY LEADING TO SNOW/IFR VSBY POTENTIAL AT ORD/MDW/DPA
THROUGH THE AFTERNOON.
MDB
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* HIGH CONFIDENCE IN WIND TRENDS. MEDIUM-HIGH CONFIDENCE IN SEEING
GUSTS AROUND 35 KT.
* HIGH CONFIDENCE IN SCATTERED SNOW SHOWERS OCCURRING THIS
MORNING...OCNLLY REDUCING VIS TO IFR OR LIFR. LOWEST VIS WILL
LIKELY BE BRIEF. LOW CONFIDENCE DURATION OF VIS RESTRICTION TO
IFR OR LIFR.
* HIGH CONFIDENCE IN GENERAL CIG TREND AND SCATTERING THIS
AFTERNOON. INTERMITTENT LOWER END MVFR CIGS IN HEAVIER
SHSN...OCNL LOWER END VFR CIGS MAY OCCUR THROUGH THE MORNING AS
WELL.
* CONFIDENCE IN SNOW FORECAST FOR SUNDAY.
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT...MVFR POSSIBLE.
MONDAY...MVFR. SLIGHT CHANCE OF SNOW. SOUTHWEST WINDS.
TUESDAY THROUGH THURSDAY...PERIODS OF MVFR POSSIBLE. WEST TO
NORTHWEST WINDS.
FRIDAY...VFR. SOUTHWEST WINDS.
MDB
&&
.MARINE...
317 AM CST
LOW PRESSURE JUST EAST OF LAKE SUPERIOR OR OVER NORTHERN GEORGIAN
BAY WILL MOVE SOUTHEAST TO THE SOUTHERN NEW ENGLAND COAST INTO
TONIGHT WHILE STRENGTHENING. VERY STRONG HIGH PRESSURE OVER THE
CANADIAN PRAIRIES WILL SETTLE SOUTHWARD INTO THE MID AND UPPER
MISSISSIPPI RIVER VALLEY AND WESTERN GREAT LAKES INTO SUNDAY.
WINDS ARE SHIFTING FROM SOUTHWEST TO NORTHWEST AS A STRONG COLD
FRONT PUSHES SOUTHWARD DOWN THE LAKE THIS MORNING. WITH THE LOW
DEEPENING AND THE VERY STRONG HIGH ALLOWING FOR AN INCREASING
PRESSURE GRADIENT AND THEN COMBINING WITH THE STRONG COLD
ADVECTION BEHIND THE FRONT...WINDS WILL QUICKLY RAMP UP EARLY THIS
MORNING. PEAK WINDS ARE EXPECTED FROM MID/LATE MORNING THROUGH THE
AFTERNOON BEFORE SLOWLY EASING. 50 KT GUSTS LOOK LIKELY ACROSS
MUCH OF THE LAKE...ESPECIALLY THE SOUTHERN TWO-THIRDS...FROM LATE
MORNING THROUGH THE AFTERNOON. WITH ROUGHLY 6 HOURS OF GALES
EXPECTED PRIOR TO THE STORM FORCE WINDS...HAVE OPTED TO KEEP A
GALE WARNING IN EFFECT OUT THE GATE UNTIL A STORM WARNING TAKES
OVER AT 15Z FOR THE OPEN WATERS. HAVE THEN KEPT THE EXISTING GALE
WARNING FROM MID EVENING INTO THE OVERNIGHT. WILL KEEP NEARSHORE
AREAS IN A GALE...WITH STORM FORCE WINDS MORE LIKELY TO THE
EAST...BUT WILL MENTION POSSIBLE STORM FORCE GUSTS FOR THE INDIANA
WATERS. BETWEEN THE WINDS AND WAVES HEAVY FREEZING SPRAY WILL
OCCUR AND HAVE MAINTAINED THE HEAVY FREEZING SPRAY WARNING.
THE HIGH MOVES ACROSS THE GREAT LAKES SUNDAY THROUGH MONDAY WHICH
WILL LEAD TO WINDS WHICH WILL TURN EASTERLY SUNDAY AND SUNDAY NIGHT
BEFORE SOUTHWEST WINDS TAKE OVER AHEAD OF THE NEXT SERIES OF LOW
PRESSURE SYSTEMS. THIS WILL MEAN ANOTHER PERIOD OF NORTHERLY WINDS
AS WELL AS VERY COLD TEMPERATURES BY WEDNESDAY. HIGH PRESSURE IS
THEN EXPECTED TO RETURN LATE NEXT WEEK.
MDB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WIND CHILL ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-
ILZ023-ILZ032-ILZ033-ILZ039...8 PM SATURDAY TO 9 AM SUNDAY.
IN...WIND ADVISORY...INZ001 UNTIL 6 PM SATURDAY.
WIND CHILL ADVISORY...INZ001-INZ010-INZ011-INZ019...8 PM
SATURDAY TO 9 AM SUNDAY.
WINTER STORM WARNING...INZ002 UNTIL 9 AM SUNDAY.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 AM SATURDAY.
GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...9 PM SATURDAY TO 3 AM
SUNDAY.
HEAVY FREEZING SPRAY WARNING...LMZ080-LMZ261-LMZ362-LMZ364-
LMZ366-LMZ563-LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-
LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-
LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 3 AM SUNDAY.
STORM WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 PM SATURDAY.
GALE WARNING...NEARSHORE WATERS UNTIL 3
AM SUNDAY.
&&
$$
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Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
552 AM CST Sat Feb 14 2015
.SHORT TERM...(Today)
ISSUED AT 330 AM CST SAT FEB 14 2015
The Arctic cold front has reached southeastern Iowa and it should
reach near the Illinois river around sunrise, then progress across
the remainder of our counties this morning. The 00z models continue
to show a band of snow showers along and behind the front, with the
higher accumulations concentrating on the southwestern half of our
forecast area this morning. The upstream radar and satellite images
seem to be correlating well with the RAP area of 700-850mb
frontogenetic forcing. The forecast soundings still show limited
deep layer moisture, with disjointed saturated layers during the
morning. Dry air will likely limit the snowfall potential of the
system, but narrow bands of enhanced lift could linger in localized
areas as the mid-level forcing advances across C IL. Isolated bands
of up to 1 inch can not be ruled out in those cases, but most areas
should stay below a half inch, with some areas just seeing trace
amounts. Pinpointing exact locations of the bands is difficult even
this close to the event, and ongoing evaluation of correlating RAP
F-gen with radar and satellite will be needed through the morning to
keep any localized bands of heavier snow covered in the gridded
forecast.
Have advanced a band of likely PoPs this morning across our
southwest areas, but also included an hour or two of likely PoPs as
far north as Lincoln to Paris. Chance PoPs were included for at
least a couple hours in all of our northern counties at some point
this morning when the F-gen and moisture best coincide.
Temps will be steady or falling through the day. High temps for this
calendar day most likely will occur early this morning ahead of the
cold front. Strong pressure rises this afternoon will cause blustery
northwest winds to develop, with sustained speeds of 20-30 mph and a
few gusts around 40 mph. Wind chills by late afternoon will dip
below zero across all of our area, with -10 to -15F north of Peoria
already by 00z/6pm.
&&
.LONG TERM...(Tonight through Friday)
ISSUED AT 330 AM CST SAT FEB 14 2015
Vigorous short wave to track into the mid Atlantic states this
evening and deepen a very strong surface low off the New England
coast tonight. This to bring yet another blizzard to coastal New
England including Boston tonight into Sunday. But for IL the main
story will be the bitter cold temperatures and wind chills. Will
issue a wind chill advisory tonight starting at 6 pm and go until 9
am Sunday for areas from Canton to Lincoln to Terre Haute northeast
where wind chills get down to 15-20 below zero. Lows overnight range
from zero to 5 below from Lincoln and Champaign north to 0 to 5
above south from I-72 south.
Strong 1046 mb arctic high pressure over nw Manitoba to weaken to
1035 mb as it drifts into the Great Lakes region Sunday afternoon.
Meanwhile a weak northern stream short wave will dive se from the
Pacific Northwest into the MO valley Sunday evening and bring chance
of light snow and flurries to areas sw of Lincoln later Sunday
afternoon into Sunday night. Snow accumulations of a dusting to up
to a half inch sw third of CWA possible with better chances of light
snow accumulations over sw and southern IL. Cold highs Sunday in the
teens. Lows Sunday night around 5F from I-74 ne to around 10F sw
CWA.
Dry conditions prevail Monday and Monday night with surface ridge
over IL with partly to mostly cloudy skies. Highs in mid to upper
20s which is still 10-15 degrees below normal for mid February.
00Z models continue to keep a stronger southern stream wx system
south of central IL Tue with surface low over southern MS river
valley. Have just chance of flurries far sw/southern counties on
Tue. Another surge of arctic air arrives Tue night through Wed night
with wind chills reaching near or a bit colder than 15 below over
northern counties. Dry conditions prevail rest of the week as temps
modify into low to mid 30s Friday afternoon.
The Climate Prediction Center (CPC) Day 8-14 Temperature Outlook for
Feb 21-27th has IL in a greater than 80% chance of below normal
temperatures, and this covers the Great Lakes region including IN/OH.
So winter`s grip looks to continue across the region the rest of the
month as upper level trof generally prevails over eastern North America
east of the Rockies.
&&
.AVIATION...(For the 12Z TAFS through 12Z Sunday morning)
ISSUED AT 551 AM CST SAT FEB 14 2015
Low VFR cigs will start off the morning, with light snow showers
developing under a band of 700-850mb frontogenesis. The better
chances for steadier snows and light snow accums should be in our
southern counties, including SPI and possibly DEC. Have put MVFR
cigs in those locations this morning during snow showers and
reduced vis to 2SM at times. Isolated bands of heavier snows could
develop, where visibility dips to less than a mile as fluffy snow
falls, but chances are to low to pin-point them occurring at any
TAF site. Snow showers will diminish by 18z, with a few flurries
possibly lingering early this afternoon in eastern areas, possibly
including DEC and CMI. Low VFR cloud cover may become SCT-BKN this
afternoon as dry air begins to mix down into the boundary layer,
creating cloud streets of strato-cu.
Winds will start out WNW in the 10-15kt range, but will increase
to 20-25kt and gusting to 35 kt later this morning and this
afternoon behind the cold front. Strong wind gusts could continue
this evening, but should diminish by 06z. However, sustained
12-15kt is expected through the end of the TAF period.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY from 6 PM this evening to 9 AM CST Sunday
FOR ILZ027>031-036>038-041>046-055-057.
&&
$$
SHORT TERM...Shimon
LONG TERM...07
AVIATION...Shimon
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
337 AM CST SAT FEB 14 2015
.SHORT TERM...
332 AM CST
THROUGH SUNDAY...
NO CHANGES TO GOING HEADLINES FOR TODAY. HOWEVER...WE HAVE ISSUED A
WIND CHILL ADVISORY FOR THE AREA FOR TONIGHT.
MAIN WEATHER FORECAST CONCERNS CONTINUE TO FOCUS ON THE STRONG
ARCTIC PUSH TODAY...WITH DANGEROUS WIND CHILLS TONIGHT...AND ALSO
THE LAKE EFFECT SNOW SHOWERS...PARTICULARLY ACROSS NORTHWESTERN
INDIANA LATER TODAY AND TONIGHT...THEN OVER NORTHEASTERN ILLINOIS ON
SUNDAY.
WATER VAPOR IMAGERY EARLY THIS MORNING SHOWS THE MAIN UPPER LEVEL PV
ANOMALY RAPIDLY DIGGING SOUTHWARD OVER NORTHERN WISCONSIN.
MEANWHILE...THE ASSOCIATED SURFACE LOW CONTINUES TO DEEPEN TO NEAR
1000 MB OVER THE UPPER GREAT LAKES REGION...WITH THE MAIN SURFACE
COLD FRONT RIGHT ON OUR DOOR STEP ACROSS FAR NORTHERN ILLINOIS.
TEMPERATURES AHEAD OF THIS FRONT AT STILL QUITE MILD IN THE UPPER
20S TO NEAR 30. HOWEVER...THE BOTTOM WILL FALL OUT IN A HURRY HERE
OVER THE NEXT FEW HOURS...AS TEMPERATURES QUICKLY TUMBLE INTO THE
TEENS AFTER DAYBREAK TODAY...AND CONTINUE TO FALL INTO THE SINGLE
DIGITS THIS AFTERNOON.
LOWER LEVEL LAPS RATES WILL STEEP UP FOLLOWING THE FRONTAL
PASSAGE...AND THIS SHOULD ALLOW FOR THE DEVELOPMENT OF SOME ISOLATED
TO SCATTERED SNOW SHOWERS ACROSS THE REGION THIS MORNING.
HOWEVER...IT APPEARS THE BETTER FOCUS FOR SNOW SHOWERS...OUTSIDE OF
LAKE EFFECT...WILL OCCUR ACROSS MY SOUTHERN AREAS THIS MORNING AS THE
LOWER LEVEL BAROCLINIC ZONE CONTINUES TO STRENGTHEN...SETTING UP A
BAND OF STRONG FGEN ACROSS CENTRAL ILLINOIS THIS MORNING. THIS WILL
BE A SHORT LIVED FEATURE...HOWEVER...SO SNOW AMOUNTS AREA-WIDE WILL
LIKELY REMAIN A HALF IN OR LESS.
NORTHERLY WINDS WILL INCREASE QUICKLY THIS MORNING...AND THE
COMBINATION OF VERY STRONG COLD AIR ADVECTION...AND RAPID PRESSURE
RISES...COULD RESULT IN A PERIOD OF NEAR WIND ADVISORY CRITERIA WINDS
(GUSTS TO 45 MPH)...PARTICULARLY ACROSS EASTERN ILLINOIS AND
NORTHWESTERN INDIANA LATER THIS MORNING AND INTO THE AFTERNOON.
MODEL SOUNDINGS ACROSS THESE AREAS INDICATE MEAN MIXING LAYER WINDS
AROUND 36 KT...WITH AROUND 40 TO 42 KT AT THE TOP OF MIXING LAYER.
STRONGLY FORCED COLD AIR ADVECTION REGIMES SUCH AS WHAT IS EXPECTED
THIS MORNING...CAN SET UP SITUATIONS WHEN SOME OF THE HIGHEST WINDS
IN THE MIXING LAYER MIX DOWN TO THE SURFACE AS WIND GUSTS...AT LEAST
FOR SHORT PERIODS OF TIME. IF THIS DOES OCCUR...THERE COULD BE A
SHORT PERIOD WITH WIND GUSTS TOPPING 45 MPH TODAY. OVERALL IT
APPEARS THE STRONGEST WIND POTENTIAL WILL BE NEAR THE LAKE IN
NORTHWESTERN INDIANA...AND THIS AREA IS CURRENTLY COVERED BY EITHER
A WIND ADVISORY OR A WINTER STORM WARNING. WE THOUGHT ABOUT POSSIBLY
EXPANDING THE WIND ADVISORY TO INCLUDE ALL OF NORTHWESTERN INDIANA
AND SOME OF EASTERN ILLINOIS. HOWEVER...AFTER COLLABORATING WITH
NEIGHBORING OFFICES...WE HAVE DECIDED NOT TO EXPAND THE CURRENT WIND
ADVISORY.
THE LAKE EFFECT POTENTIAL IS REALLY UNCHANGED FROM PREVIOUS
FORECASTS. IT STILL APPEARS THAT THE MAIN SETUP TODAY WILL FAVOR
NORTHEASTERN PORTER COUNTY INDIANA AND POINTS EAST...AS STRONG
NORTHWESTERN BOUNDARY LAYER WINDS KEEP THE BETTER LOWER LEVEL
CONVERGENCE MORE BROAD...AND MAINLY TO THE EAST OF MY AREA. THIS
COULD SUPPORT MULTIPLE BANDS OF LAKE EFFECT SNOW SHOWERS. HOWEVER...IT
STILL DOES APPEAR THAT AS A STOUT SURFACE BUILDS EASTWARD ACROSS THE
UPPER MIDWEST BY THIS EVENING...THAT THE BOUNDARY LAYER WINDS OVER
LAKE MICHIGAN WILL BECOME MORE NORTHERLY...AND GRADUALLY EASE IN
MAGNITUDE OVERNIGHT TONIGHT. THIS COULD SET UP MORE OF A SINGLE
CONVERGENT WESTWARD MOVING BAND OF LAKE EFFECT SNOW SHOWERS OVER
SOUTHERN LAKE MICHIGAN TONIGHT...AND BETTER ACCUMULATION POTENTIAL
FOR MY NORTHWESTERN INDIANA COUNTIES NEAR THE LAKE. INVERSION
HEIGHTS SHOULD BE ON A DECLINE DURING THIS TIME. HOWEVER...GIVEN THE
COLD AIRMASS...THE CLOUDS SHOULD BE COLD ENOUGH TO SUPPORT ICE
CRYSTALS. TOTAL SNOWFALL AMOUNTS SHOULD NOT GET TO OUT OF HAND...AS
THE BAND SHOULD BECOME PROGRESSIVE. HOWEVER...AMOUNTS IN EXCESS OF 6
INCHES ARE STILL POSSIBLE ACROSS PORTIONS OF THE WARNING AREA.
ADDITIONALLY...WITH THE STRONG WINDS TODAY AND THIS EVENING...BLOWING
SNOW AND WHITE OUT CONDITIONS WILL BE A CONCERN AT TIMES.
WINDS OVER THE LAKE WILL CONTINUE TO BACK MORE NORTHEASTERLY FOR A
PERIOD ON SUNDAY...SO SOME LIGHT LAKE EFFECT SNOW SHOWERS APPEAR
LIKELY ACROSS THE CHICAGO AREA OF NORTHEASTERN ILLINOIS.
HOWEVER...THE BAND OF SNOW SHOWERS LOOKS TO BECOME A LESS ORGANIZED
BY SUNDAY. THEREFORE...IT STILL APPEARS THAT ACCUMULATIONS ACROSS
THE CHICAGO AREA WILL GENERALLY REMAIN ON THE LIGHT SIDE. THE WINDS
ARE EXPECTED SHIFT OFFSHORE BY EARLY SUNDAY EVENING...SO ANY
LINGERING SHOWERS WILL END BY THIS TIME.
A WIND CHILL ADVISORY WILL GO INTO EFFECT FOR THE REGION THIS
EVENING. THE COMBINATION OF LINGERING BREEZY WINDS AND TEMPERATURES
FALLING INTO NEGATIVE TERRITORY THROUGH THE EVENING WILL SET UP WIND
CHILLS OF 20 BELOW TO 30 BELOW...WITH THE COLDEST EXPECTED ACROSS
NORTH CENTRAL ILLINOIS. THIS ADVISORY WILL BE IN EFFECT UNTIL MID
MORNING ON SUNDAY. TEMPERATURES LOOK TO ONLY TOP OUT NEAR 10 ABOVE IN
MOST AREAS ON SUNDAY...BUT WITH LIGHT WINDS DURING THE DAY...WIND
CHILLS SHOULD NOT BE AN ISSUE.
KJB
&&
.LONG TERM...
332 AM CST
SUNDAY NIGHT THROUGH FRIDAY...
THE WEATHER PATTERN OVER THE COUNTRY WILL CONTINUE TO FAVOR
PERIODS OF COLD ARCTIC OUTBREAKS OVER THE EASTERN HALF OF THE
CONUS NEXT WEEK. STRONG HIGH LATITUDE UPPER RIDGING OVER THE EASTERN
PACIFIC/WESTERN NORTH AMERICA WILL SET THE STAGE FOR A FAIRLY
PROLONGED PERIOD OF MUCH BELOW NORMAL HEIGHTS AND TEMPERATURES
ACROSS MUCH OF EASTERN NORTH AMERICA. OUTSIDE OF LAKE EFFECT
SNOWS...NO BIG SNOW EVENTS ARE EXPECTED THROUGH THE PERIOD.
HOWEVER...SOME MINOR SNOW SYSTEMS COULD IMPACT THE AREA WITHIN THE
CYCLONIC UPPER LEVEL FLOW PATTERN. A REINFORCING SHOT OF COLD
ARCTIC AIR LOOKS TO SET UP OVER THE AREA BY MID WEEK...AND THIS
AIRMASS COULD EVEN BE A BIT COLDER THAN THE SHORT TERM COLD
EXPECTED. THIS COULD RESULT IN HIGH TEMPERATURES ONLY IN THE
SINGLE DIGITS IN MOST AREAS ON WEDNESDAY.
KJB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 09Z...
* MAINLY MVFR CIGS THROUGH EARLY AFTERNOON...WITH SOME BREAKS
POSSIBLE LATE TONIGHT.
* WINDS SHIFT NORTHWEST EARLY THIS MORNING AND INCREASE IN SPEED.
GUSTS TO AROUND 35 KT FROM MID MORNING THROUGH AT LEAST MID
AFTERNOON BEFORE GRADUALLY EASING.
* SCATTERED SNOW SHOWERS AND INTERMITTENT IFR VSBY POSSIBLE FROM
AROUND DAYBREAK THROUGH MID/LATE MORNING.
MDB
//DISCUSSION...UPDATED 06Z...
LOW PRESSURE TO THE EAST OF LAKE SUPERIOR WILL CONTINUE TO MOVE
SOUTHEAST THROUGH THE DAY WHILE STRONG HIGH PRESSURE MOVES INTO
THE NORTHERN PLAINS AND UPPER MISSISSIPPI RIVER VALLEY. WEST-
SOUTHWEST WINDS CURRENTLY IN PLACE WILL TURN WEST-NORTHWEST THEN
NORTHWEST THROUGH DAYBREAK AS A COLD FRONT CROSSES THE AREA. THE
PRESSURE GRADIENT WILL STRENGTHEN AS THE HIGH BUILDS IN AND
COMBINE WITH A STRONG PUSH OF COLD AIR BRINGING GUSTY WINDS
THROUGH EARLY THIS EVENING. SPEEDS OF 20-25 KT ARE EXPECTED BY MID
MORNING WITH GUSTS INTO THE 30-35 KT RANGE...WITH SOME 35-40 KT
GUSTS POSSIBLE AT TIMES...ESPECIALLY AT GYY GIVEN THEIR PROXIMITY
TO THE LAKE. WINDS WILL EASE THIS EVENING.
CIGS HAVE SLOWLY BEEN LOWERING TO MVFR AND WILL CONTINUE TO LOWER
EARLY TONIGHT. SATELLITE SHOWS A CLEARING WEDGE ACROSS SOUTHEAST
MINNESOTA AND WEST-CENTRAL WISCONSIN WHICH IS WORKING SOUTHEAST
BUT STRATUS ACROSS NORTHERN WISCONSIN IS PUSHING SOUTHWARD AND
WILL LIKELY CLOSE THE GAP. WILL KEEP CIGS IN PLACE OVERNIGHT BUT
SOME SCATTERING IS POSSIBLE TOWARD 10Z OR SO FOR A FEW HOURS.
SNOW SHOWERS ARE EXPECTED TO DEVELOP BY AROUND DAYBREAK AS THE
COLD AIR PUSHES IN. COVERAGE IS SOMEWHAT QUESTIONABLE BUT DO
EXPECT ACTIVITY. WILL CONTINUE WITH A PERIOD OF IFR VSBY IN SHSN
BUT MAY BE ABLE TO ADJUST THIS WITH LATER UPDATES TO SHOW MORE
INTERMITTENT VSBY REDUCTION. CIGS ARE EXPECTED TO SCATTER/CLEAR
LATER THIS AFTERNOON WITH LITTLE IN THE WAY OF CLOUDS THIS
EVENING/TONIGHT.
MDB
//ORD AND MDW CONFIDENCE...UPDATED 09Z...
* HIGH CONFIDENCE IN MVFR CIGS. MEDIUM CONFIDENCE IN TIME OF
SCATTERING THIS AFTERNOON.
* HIGH CONFIDENCE IN WIND TRENDS AND SEEING GUSTS AROUND 35 KT.
* MEDIUM-HIGH CONFIDENCE IN SHSN DEVELOPING THIS MORNING BUT LOW-
MEDIUM CONFIDENCE IN COVERAGE AND DURATION OF VSBY REDUCTION.
MDB
//OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z...
SUNDAY...LAKE EFFECT SNOW SHOWERS LIKELY WITH POTENTIAL IFR.
NORTHEAST WINDS.
MONDAY...MVFR. SLIGHT CHANCE OF SNOW. SOUTHWEST WINDS.
TUESDAY THROUGH THURSDAY...PERIODS OF MVFR POSSIBLE. WEST TO NORTHWEST
WINDS.
RATZER
&&
.MARINE...
317 AM CST
LOW PRESSURE JUST EAST OF LAKE SUPERIOR OR OVER NORTHERN GEORGIAN
BAY WILL MOVE SOUTHEAST TO THE SOUTHERN NEW ENGLAND COAST INTO
TONIGHT WHILE STRENGTHENING. VERY STRONG HIGH PRESSURE OVER THE
CANADIAN PRAIRIES WILL SETTLE SOUTHWARD INTO THE MID AND UPPER
MISSISSIPPI RIVER VALLEY AND WESTERN GREAT LAKES INTO SUNDAY.
WINDS ARE SHIFTING FROM SOUTHWEST TO NORTHWEST AS A STRONG COLD
FRONT PUSHES SOUTHWARD DOWN THE LAKE THIS MORNING. WITH THE LOW
DEEPENING AND THE VERY STRONG HIGH ALLOWING FOR AN INCREASING
PRESSURE GRADIENT AND THEN COMBINING WITH THE STRONG COLD
ADVECTION BEHIND THE FRONT...WINDS WILL QUICKLY RAMP UP EARLY THIS
MORNING. PEAK WINDS ARE EXPECTED FROM MID/LATE MORNING THROUGH THE
AFTERNOON BEFORE SLOWLY EASING. 50 KT GUSTS LOOK LIKELY ACROSS
MUCH OF THE LAKE...ESPECIALLY THE SOUTHERN TWO-THIRDS...FROM LATE
MORNING THROUGH THE AFTERNOON. WITH ROUGHLY 6 HOURS OF GALES
EXPECTED PRIOR TO THE STORM FORCE WINDS...HAVE OPTED TO KEEP A
GALE WARNING IN EFFECT OUT THE GATE UNTIL A STORM WARNING TAKES
OVER AT 15Z FOR THE OPEN WATERS. HAVE THEN KEPT THE EXISTING GALE
WARNING FROM MID EVENING INTO THE OVERNIGHT. WILL KEEP NEARSHORE
AREAS IN A GALE...WITH STORM FORCE WINDS MORE LIKELY TO THE
EAST...BUT WILL MENTION POSSIBLE STORM FORCE GUSTS FOR THE INDIANA
WATERS. BETWEEN THE WINDS AND WAVES HEAVY FREEZING SPRAY WILL
OCCUR AND HAVE MAINTAINED THE HEAVY FREEZING SPRAY WARNING.
THE HIGH MOVES ACROSS THE GREAT LAKES SUNDAY THROUGH MONDAY WHICH
WILL LEAD TO WINDS WHICH WILL TURN EASTERLY SUNDAY AND SUNDAY NIGHT
BEFORE SOUTHWEST WINDS TAKE OVER AHEAD OF THE NEXT SERIES OF LOW
PRESSURE SYSTEMS. THIS WILL MEAN ANOTHER PERIOD OF NORTHERLY WINDS
AS WELL AS VERY COLD TEMPERATURES BY WEDNESDAY. HIGH PRESSURE IS
THEN EXPECTED TO RETURN LATE NEXT WEEK.
MDB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WIND CHILL ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-
ILZ023-ILZ032-ILZ033-ILZ039...8 PM SATURDAY TO 9 AM SUNDAY.
IN...WIND ADVISORY...INZ001...9 AM SATURDAY TO 6 PM SATURDAY.
WIND CHILL ADVISORY...INZ001-INZ010-INZ011-INZ019...8 PM
SATURDAY TO 9 AM SUNDAY.
WINTER STORM WARNING...INZ002...9 AM SATURDAY TO 9 AM SUNDAY.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 AM SATURDAY.
GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...9 PM SATURDAY TO 3 AM
SUNDAY.
HEAVY FREEZING SPRAY WARNING...LMZ080-LMZ261-LMZ362-LMZ364-
LMZ366-LMZ563-LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-
LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-
LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 3 AM SUNDAY.
STORM WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...9 AM SATURDAY TO 9 PM
SATURDAY.
GALE WARNING...NEARSHORE WATERS UNTIL 3
AM SUNDAY.
&&
$$
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Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
331 AM CST Sat Feb 14 2015
.SHORT TERM...(Today)
ISSUED AT 330 AM CST SAT FEB 14 2015
The Arctic cold front has reached southeastern Iowa and it should
reach near the Illinois river around sunrise, then progress across
the remainder of our counties this morning. The 00z models continue
to show a band of snow showers along and behind the front, with the
higher accumulations concentrating on the southwestern half of our
forecast area this morning. The upstream radar and satellite images
seem to be correlating well with the RAP area of 700-850mb
frontogenetic forcing. The forecast soundings still show limited
deep layer moisture, with disjointed saturated layers during the
morning. Dry air will likely limit the snowfall potential of the
system, but narrow bands of enhanced lift could linger in localized
areas as the mid-level forcing advances across C IL. Isolated bands
of up to 1 inch can not be ruled out in those cases, but most areas
should stay below a half inch, with some areas just seeing trace
amounts. Pinpointing exact locations of the bands is difficult even
this close to the event, and ongoing evaluation of correlating RAP
F-gen with radar and satellite will be needed through the morning to
keep any localized bands of heavier snow covered in the gridded
forecast.
Have advanced a band of likely PoPs this morning across our
southwest areas, but also included an hour or two of likely PoPs as
far north as Lincoln to Paris. Chance PoPs were included for at
least a couple hours in all of our northern counties at some point
this morning when the F-gen and moisture best coincide.
Temps will be steady or falling through the day. High temps for this
calendar day most likely will occur early this morning ahead of the
cold front. Strong pressure rises this afternoon will cause blustery
northwest winds to develop, with sustained speeds of 20-30 mph and a
few gusts around 40 mph. Wind chills by late afternoon will dip
below zero across all of our area, with -10 to -15F north of Peoria
already by 00z/6pm.
&&
.LONG TERM...(Tonight through Friday)
ISSUED AT 330 AM CST SAT FEB 14 2015
Vigorous short wave to track into the mid Atlantic states this
evening and deepen a very strong surface low off the New England
coast tonight. This to bring yet another blizzard to coastal New
England including Boston tonight into Sunday. But for IL the main
story will be the bitter cold temperatures and wind chills. Will
issue a wind chill advisory tonight starting at 6 pm and go until 9
am Sunday for areas from Canton to Lincoln to Terre Haute northeast
where wind chills get down to 15-20 below zero. Lows overnight range
from zero to 5 below from Lincoln and Champaing north to 0 to 5
above south from I-72 south.
Strong 1046 mb arctic high pressure over nw Manitoba to weaken to
1035 mb as it drifts into the Great Lakes region Sunday afternoon.
Meanwhile a weak northern stream short wave will dive se from the
Pacific Northwest into the MO valley Sunday evening and bring chance
of light snow and flurries to areas sw of Lincoln later Sunday
afternoon into Sunday night. Snow accumulations of a dusting to up
to a half inch sw third of CWA possible with better chances of light
snow accumulations over sw and southern IL. Cold highs Sunday in the
teens. Lows Sunday night around 5F from I-74 ne to around 10F sw
CWA.
Dry conditions prevail Monday and Monday night with surface ridge
over IL with partly to mostly cloudy skies. Highs in mid to upper
20s which is still 10-15 degrees below normal for mid February.
00Z models continue to keep a stronger southern stream wx system
south of central IL Tue with surface low over southern MS river
valley. Have just chance of flurries far sw/southern counties on
Tue. Another surge of arctic air arrives Tue night through Wed night
with wind chills reaching near or a bit colder than 15 below over
northern counties. Dry conditions prevail rest of the week as temps
modify into low to mid 30s Friday afternoon.
The Climate Prediction Center (CPC) Day 8-14 Temperature Outlook for
Feb 21-27th has IL in a greater than 80% chance of below normal
temperatures, and this covers the Great Lakes region including IN/OH.
So winter`s grip looks to continue across the region the rest of the
month as upper level trof generally prevails over eastern North America
east of the Rockies.
&&
.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
ISSUED AT 1110 PM CST FRI FEB 13 2015
Low VFR cigs have dominated this evening and expect that to
continue until around 09z when a frontal boundary will approach
the area with occasional MVFR cigs with scattered snow showers.
At this point, it appears the better threat for a more organized
band of light snow will be over west central thru southeast IL
in the 11z-16z time frame where cigs and vsbys may drop briefly
to IFR. May see several narrow but intense bands of snow showers
develop towards dawn and track quickly from northwest to southeast.
Just where these narrow bands will setup and which TAF site they
will affect is still not that clear cut at this time. Will add
a tempo group for SPI and DEC for now and see how the band to our
northwest eventually sets up to see if we need to add lower cigs
and vsbys further north late tonight as well. Not looking at much
in the way of any accumulations with around a half inch possible in
a few locations tomorrow morning.
Any snow showers and lower vsbys/cigs will quickly move from
northwest to southeast during the morning and be out of the TAF
area by 18z with some scattered stratocumulus developing in the
strong cold advection pattern Saturday afternoon. Southwest winds
tonight of 10 to 15 kts will shift into the northwest by 11z
in PIA and by 14z in CMI. Look for a rapid increase in wind
speeds tomorrow morning with prevailing speeds of 15 to 25 kts
with gusts as high as 35 kts at times tomorrow morning into the
mid afternoon hours of Saturday before we see the winds gradually
diminish towards sunset Saturday evening.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY from 6 PM this evening to 9 AM CST Sunday
FOR ILZ027>031-036>038-041>046-055-057.
&&
$$
SHORT TERM...Shimon
LONG TERM...07
AVIATION...Smith
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1200 AM CST SAT FEB 14 2015
.SHORT TERM...
328 PM CST
THROUGH SUNDAY...
HEADLINES: HAVE ISSUED A WINTER STORM WARNING FOR PORTER COUNTY
AND A WIND ADVISORY FOR LAKE COUNTY INDIANA...IN EFFECT STARTING
MID SATURDAY MORNING.
MAIN CONCERNS IN THE SHORT TERM:
*SCATTERED SNOW SHOWERS WITH ARCTIC FRONT LATE TONIGHT INTO
EARLY/MID SATURDAY MORNING.
ARCTIC FRONT TRAILING FROM LOW PRESSURE CURRENTLY OVER LAKE
SUPERIOR WILL SWEEP ACROSS THE AREA LATE TONIGHT. CORE OF -26 TO
-28C AIRMASS AT 850 MB WILL RUSH INTO THE AREA...RESULTING IN
QUICKLY STEEPENING LOW LEVEL LAPSE RATES. THIS AND NOSE OF 130+KT
UPPER JET ALONG WITH STRONG PVA FROM SHORTWAVE NOTED ON W/V
IMAGERY THIS AFTERNOON OVER WESTERN ONTARIO DIVING SOUTHWARD WILL
ENHANCE LIFT...RESULTING IN SCATTERED SNOW SHOWERS BREAKING OUT.
NOT ALL AREAS WILL SEE ANYTHING MORE THAN A DUSTING...BUT SOME
LOCATIONS ESPECIALLY ALONG AND SOUTH OF INTERSTATE 80 COULD SEE
ROUGHLY BETWEEN A HALF INCH AND INCH OF ACCUMULATION.
CONFIDENCE IN MEDIUM-HIGH IN SNOW SHOWERS DEVELOPING AREA
WIDE...BUT HAVE MAINTAINED MID-HIGH CHANCE POPS AS EXPECTATION IS
FOR COVERAGE OF MEASURABLE SNOW TO BE SCATTERED IN NATURE.
*PLUMMETING TEMPERATURES AND VERY STRONG WINDS RESULTING IN
BITTERLY COLD WIND CHILLS LATE VALENTINES DAY INTO SATURDAY NIGHT
AND EARLY SUNDAY.
AFOREMENTIONED HIGHLY ANOMALOUS THERMAL TROUGH WILL SURGE INTO
AREA ON SATURDAY MORNING BEHIND ARCTIC FRONT. THUS HIGHS FOR THE
DAY WILL OCCUR EARLY...FOLLOWED BY QUICKLY FALLING TEMPERATURES
INTO THE SINGLE DIGITS AREA WIDE BY MID-LATE AFTERNOON. MAKING
MATTERS WORSE WILL BE RAPID NEARLY 6MB PER 3 HOUR PRESSURE RISES
LATE MORNING INTO THE EARLY AFTERNOON AS NEARLY 1050 MB ARCTIC
HIGH SPREADS SOUTH AND CLIPPER LOW DEEPENS TO SUB 1000 MB OVER
EASTERN LAKES. THIS WILL RESULT IN NORTH-NORTHWEST GUSTS TAPPING
MID TO EVEN HIGH 30S KT SPEEDS ALOFT...TRANSLATING INTO 35 TO 45
MPH WIND GUSTS AT THE SURFACE. ON THE INDIANA LAKEFRONT...WINDS
FROM FRICTIONLESS LAKE ARE LIKELY TO GUST TO 45 TO 50 MPH FROM THE
LATE MORNING THROUGH MID AFTERNOON. THUS HAVE ISSUED A WIND
ADVISORY FOR LAKE COUNTY FROM 15Z TO 00Z ON SATURDAY. THERE COULD
BE MINOR BLOWING SNOW/VSBY REDUCTION ISSUES FOR PORTIONS OF LAKE
COUNTY THAT OBSERVE FALLING SNOW THROUGH THE DAY. WILL TIE IN WIND
CONCERNS IN PORTER COUNTY INTO WINTER STORM WARNING.
WINDS WILL ONLY SLOWLY DIMINISH VALENTINES DAY EVENING AND
NIGHT...SO WIND CHILL VALUES WILL FALL TO 10 TO 20 BELOW BY EARLY
EVENING...AND THEN 15 TO 30 BELOW BY LATE SATURDAY NIGHT/EARLY
SUNDAY. WILL LIKELY NEED A WIND CHILL ADVISORY FOR MUCH OF
NORTHERN IL ALONG/NORTH OF I-80...BUT WOULD LIKE TO LET NEXT SHIFT
ASSESS POTENTIAL FOR WINDS TO DIMINISH A BIT SOONER AND RESULT IN
SLIGHTLY LESS COLD WIND CHILLS BY EARLY SUNDAY BEFORE DECIDING ON
WHAT COUNTIES TO INCLUDE IN THE ADVISORY. EXPECTING LOW
TEMPERATURES IN THE SINGLE DIGITS TO AROUND 10 BELOW ZERO AWAY
FROM LAKE EFFECT CLOUDS AND CHICAGO LAKEFRONT.
WILL ISSUE AN SPS FOR WIND/BITTER COLD/SNOW SHOWERS FOR COUNTIES
NOT YET IN HEADLINES.
*PERIODS OF MODERATE TO OCCASIONALLY HEAVY LAKE EFFECT SNOW IN
PORTER COUNTY ON SATURDAY...ALONG WITH BLOWING AND DRIFTING SNOW
AND SIGNIFICANTLY REDUCED VISIBILITY. THE LAKE EFFECT SNOW WILL
SHIFT WESTWARD LATE SATURDAY NIGHT INTO SUNDAY MORNING...BRINGING
MINOR ACCUMULATIONS TO AREAS NEAR LAKE IN NORTHEAST ILLINOIS
BEFORE ACTIVITY DIMINISHES SUNDAY AFTERNOON.
NOT MUCH HAS CHANGED REGARDING THE LAKE EFFECT SETUP SATURDAY INTO
SATURDAY NIGHT. FORECAST SOUNDINGS CONTINUE TO SHOW EXTREME LAKE
INDUCED INSTABILITY AND EQUILIBRIUM LEVELS NEAR OR OVER 10KFT...THOUGH
INVERSION HEIGHTS OF 5 TO 7KFT AS BEST CONVERGENCE MOVES INTO
PORTER COUNTY MAY PRECLUDE EXCESSIVE ACCUMULATIONS. AS BOUNDARY
LAYER FLOW SHIFTS FROM NNW TO NORTHERLY SATURDAY NIGHT...STRONG
CONVERGENCE AND HIGH INSTABILITY THROUGH DGZ COULD RESULT IN
MODERATE TO HEAVY RATES...AND LOCALIZED TOTAL ACCUMULATIONS OF
OVER 6 INCHES IN NORTHEASTERN PORTER COUNTY BY SUNDAY MORNING.
MESOLOW DEVELOPMENT AND BOUNDARY FLOW THEN BECOMING NORTHEAST THEN
EAST ON SUNDAY WILL TAKE LAKE BAND THROUGH LAKE COUNTY IN AND INTO
NORTHEAST IL BEFORE DIMINISHING. AT LEAST MINOR ACCUMULATIONS ARE
LIKELY FOR MUCH OF LAKE IN...COOK SHORE AND EVEN LAKE IL...BUT
CONFIDENCE IS LOW IN WHETHER A HEADLINE WILL BE NEEDED FOR ANY OF
THOSE COUNTIES.
DESPITE CONVERGENT AXIS REMAINING TO EAST OF PORTER ON SATURDAY
MORNING AND AFTERNOON...EXTREMELY COLD AIR MASS AND NNW FLOW WILL
LIKELY RESULT IN STEADY LIGHTER TO OCCASIONALLY MODERATE SNOW
SHOWERS INTO PORTER AND POSSIBLY EVEN EASTERN LAKE COUNTY INDIANA.
COMBINATION OF: STRONG WINDS...NEW SNOW FROM THURSDAY AND FALLING
SNOW THROUGH THE DAY ON SATURDAY BLOWING AND DRIFTING AND REDUCING
VISIBILITY...IS WHY I OPTED TO START THE WSW FOR PORTER COUNTY
SATURDAY MORNING.
RC
&&
.LONG TERM...
348 PM CST
SUNDAY NIGHT THROUGH FRIDAY...
BELOW TO MUCH BELOW NORMAL TEMPERATURES...AND GENERALLY DRY
CONDITIONS THAT HAVE BEEN TYPICAL MUCH OF JANUARY AND FEBRUARY
WITH THE EXCEPTION OF THE SUPERBOWL SNOWSTORM LOOK TO BE IN PLACE
NEXT WORK WEEK. THIS WILL BE DUE TO CONTINUED HIGH AMPLITUDE
RIDGING FROM THE NORTHEASTERN PACIFIC INTO WESTERN NORTH
AMERICA...WITH TROUGHING OVER THE EASTERN HALF OF THE CONUS
KEEPING US IN DRY NORTH-NORTHWEST FLOW ALOFT. THE NEXT SHOT OF
BITTERLY COLD ARCTIC AIR WILL ARRIVE BY WEDNESDAY BEHIND A CLIPPER
SYSTEM THAT COULD BRING SOME LIGHT SNOW LATER MONDAY INTO EARLY
TUESDAY. THE LAKE EFFECT MACHINE WILL LIKELY FIRE UP AGAIN ON LAKE
MICHIGAN...BUT FROM THIS VANTAGE POINT...BOUNDARY LAYER FLOW COULD
KEEP THE BRUNT OF THE ACTIVITY EAST OF OUR NORTHWEST INDIANA
ACTIVITIES IN THE MID TO LATE WEEK PERIOD.
RC
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* MVFR CIGS THROUGH EARLY AFTERNOON...WITH SOME BREAKS POSSIBLE
LATE TONIGHT.
* WINDS SHIFT NORTHWEST OVERNIGHT AND INCREASE IN SPEED. GUSTS TO
AROUND 35 KT FROM MID MORNING THROUGH AT LEAST MID AFTERNOON
BEFORE GRADUALLY EASING.
* SCATTERED SNOW SHOWERS AND INTERMITTENT IFR VSBY POSSIBLE FROM
AROUND DAYBREAK THROUGH MID/LATE MORNING.
MDB
//DISCUSSION...UPDATED 06Z...
LOW PRESSURE TO THE EAST OF LAKE SUPERIOR WILL CONTINUE TO MOVE
SOUTHEAST THROUGH THE DAY WHILE STRONG HIGH PRESSURE MOVES INTO
THE NORTHERN PLAINS AND UPPER MISSISSIPPI RIVER VALLEY. WEST-
SOUTHWEST WINDS CURRENTLY IN PLACE WILL TURN WEST-NORTHWEST THEN
NORTHWEST THROUGH DAYBREAK AS A COLD FRONT CROSSES THE AREA. THE
PRESSURE GRADIENT WILL STRENGTHEN AS THE HIGH BUILDS IN AND
COMBINE WITH A STRONG PUSH OF COLD AIR BRINGING GUSTY WINDS
THROUGH EARLY THIS EVENING. SPEEDS OF 20-25 KT ARE EXPECTED BY MID
MORNING WITH GUSTS INTO THE 30-35 KT RANGE...WITH SOME 35-40 KT
GUSTS POSSIBLE AT TIMES...ESPECIALLY AT GYY GIVEN THEIR PROXIMITY
TO THE LAKE. WINDS WILL EASE THIS EVENING.
CIGS HAVE SLOWLY BEEN LOWERING TO MVFR AND WILL CONTINUE TO LOWER
EARLY TONIGHT. SATELLITE SHOWS A CLEARING WEDGE ACROSS SOUTHEAST
MINNESOTA AND WEST-CENTRAL WISCONSIN WHICH IS WORKING SOUTHEAST
BUT STRATUS ACROSS NORTHERN WISCONSIN IS PUSHING SOUTHWARD AND
WILL LIKELY CLOSE THE GAP. WILL KEEP CIGS IN PLACE OVERNIGHT BUT
SOME SCATTERING IS POSSIBLE TOWARD 10Z OR SO FOR A FEW HOURS.
SNOW SHOWERS ARE EXPECTED TO DEVELOP BY AROUND DAYBREAK AS THE
COLD AIR PUSHES IN. COVERAGE IS SOMEWHAT QUESTIONABLE BUT DO
EXPECT ACTIVITY. WILL CONTINUE WITH A PERIOD OF IFR VSBY IN SHSN
BUT MAY BE ABLE TO ADJUST THIS WITH LATER UPDATES TO SHOW MORE
INTERMITTENT VSBY REDUCTION. CIGS ARE EXPECTED TO SCATTER/CLEAR
LATER THIS AFTERNOON WITH LITTLE IN THE WAY OF CLOUDS THIS
EVENING/TONIGHT.
MDB
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* HIGH CONFIDENCE IN MVFR CIGS. MEDIUM CONFIDENCE IN TIME OF
SCATTERING THIS AFTERNOON.
* HIGH CONFIDENCE IN WIND TRENDS AND SEEING GUSTS AROUND 35 KT.
* MEDIUM-HIGH CONFIDENCE IN SHSN DEVELOPING THIS MORNING BUT LOW-
MEDIUM CONFIDENCE IN COVERAGE AND DURATION OF VSBY REDUCTION.
MDB
//OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z...
SUNDAY...LAKE EFFECT SNOW SHOWERS LIKELY WITH POTENTIAL IFR.
NORTHEAST WINDS.
MONDAY...MVFR. SLIGHT CHANCE OF SNOW. SOUTHWEST WINDS.
TUESDAY THROUGH THURSDAY...PERIODS OF MVFR POSSIBLE. WEST TO NORTHWEST
WINDS.
RATZER
&&
.MARINE...
221 PM CST
FOR HEADLINES...THE FREEZING SPRAY AND GALE WARNING STILL LOOK VERY
ACCURATE IN TIMING. GUIDANCE DOES NOT SUPPORT SUSTAINED STORM FORCE
GUSTS SO WILL CONTINUE TO HAVE OCNL STORM FORCE GUSTS IN THE
GLF...NO STORM FORCE HEADLINE IS EXPECTED AT THIS TIME.
HIGH PRESSURE HAS SHIFTED SE AND A WEAK LOW IS OVER SOUTH CENTRAL
ONTARIO. WINDS HAVE GRADUALLY INCREASED TO 30 KT OVER THE LAKE AND
EXPECTING THEM TO INCREASE FURTHER AS THE LOW SHIFTS OVER THE
EASTERN LAKES. THE PRESSURE GRADIENT WILL INCREASE OVERHEAD LEADING
TO GALES ACROSS THE LAKE BY EARLY SATURDAY MORNING. COULD SEE OCNL
STORM FORCE GUSTS TO 50 KT OVER THE LAKE LATE SATURDAY MORNING AND
EARLY IN THE AFTERNOON...BUT SUSTAINED STORM FORCE WINDS ARE NOT
EXPECTED AT THIS TIME. NORTH WINDS DIMINISH SATURDAY EVENING AS THE
GRADIENT WEAKENS AND THE HIGH SPREADS OVERHEAD. WINDS BECOME
NORTHEAST TO EAST SUNDAY EVENING AND CONTINUE TO VEER TO SOUTH OR
SOUTHEAST BY MONDAY MORNING. A COLD FRONT SWINGS OVER THE LAKE LATE
MONDAY NIGHT INTO EARLY TUESDAY MORNING WITH WINDS BECOMING WEST AND
THEN NORTHWEST BEHIND THE FRONT. NORTHWEST WINDS INCREASE TO 30 KT
TUESDAY NIGHT AND THEN WEAKEN AND BACK TO WEST AS A HIGH PRESSURE
SYSTEM PASSES SOUTHWEST OF LAKE THURSDAY. THE PATTERN LOOKS BUSY
GOING INTO LATE NEXT WEEK WITH ANOTHER LOW PRESSURE SYSTEM IMPACTING
THE LAKE NEXT WEEKEND.
JEE
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...WINTER STORM WARNING...INZ002...9 AM SATURDAY TO 9 AM SUNDAY.
WIND ADVISORY...INZ001...9 AM SATURDAY TO 6 PM SATURDAY.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-LMZ741-LMZ742-
LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-
LMZ874-LMZ876-LMZ878...3 AM SATURDAY TO 3 AM SUNDAY.
HEAVY FREEZING SPRAY WARNING...LMZ080-LMZ261-LMZ362-LMZ364-
LMZ366-LMZ563-LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-
LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-
LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...3 AM SATURDAY
TO 3 AM SUNDAY.
&&
$$
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Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1119 PM CST Fri Feb 13 2015
.UPDATE...
ISSUED AT 825 PM CST FRI FEB 13 2015
Latest surface analysis indicating the next Arctic cold front was
located over central Wisconsin southwest through north central
Iowa and is expected to sweep through our area between 6 and 9 AM
Saturday morning accompanied by scattered snow showers and a strong
northwest wind, gusting as high as 40 mph at times. Already starting
to see strong 3 hourly pressure rises across North Dakota indicating
the front should accelerate southeastward tonight with the latest
short term models continuing to suggest the boundary will be south
of most of our area by early afternoon.
Weak shortwave noted on the water vapor loop over western North
Dakota has a small area of light snow associated with it as it
tracks southeast. HRRR and Rapid Refresh models indicate the better
threat for snow showers with this weak wave would be over west
central thru southeast IL tomorrow morning. HRRR indicating around
0.05 inches of QPF associated with this band of light snow which
would be just under an inch of snow. However, this situation is
very similar to a couple of days ago in which we saw some very
narrow but intense bands of snow showers just behind the Artic
boundary, which lasted less than an hour in most locations with
most areas seeing less than a half inch. The main concern with
this particular front will be with the strong pressure rises
immediately behind the boundary tomorrow morning suggesting about
a 2 to 4 hour period of strong winds with gusts around 40 mph out
of the northwest tomorrow morning into the mid afternoon hours.
Whatever we see with respect to light snow should be well south of
our area by mid afternoon as the Arctic air mass settles across
the Midwest for the remainder of the weekend.
Have made some minor tweaks to the early evening temperatures
and POPs, especially across west central IL just before dawn
Saturday. The rest of the forecast is right on track this evening.
Updated ZFP out by 900 PM.
&&
.SHORT TERM...(Tonight)
ISSUED AT 257 PM CST FRI FEB 13 2015
Arctic cold front currently across the Upper Midwest will drop
southward into north-central Illinois tonight, reaching the I-74
corridor by dawn Saturday. Models continue to depict a band of
snow-showers accompanying the front as it quickly passes late
tonight into Saturday morning. 18z NAM time-height cross-sections
show strong lift within the 850-700mb layer along/ahead of the
boundary, but do not indicate full saturation within the profile.
Despite lack of deep moisture, think low-level convergence/lift will
be sufficient to trigger scattered snow-showers across the northern
KILX CWA late tonight. Have therefore included chance PoPs
along/north of I-74 after 3am. Further south, dry conditions will
prevail through the night. Winds will initially be W/SW this
evening, but will veer to the N/NW and increase markedly once the
front passes. Will likely see wind gusts in the 30-35mph range
across the far north by dawn. Overnight low temperatures will
mainly be in the lower to middle 20s, but will drop into the teens
north of a Canton to Bloomington-Normal line.
&&
.LONG TERM...(Saturday through Friday)
ISSUED AT 257 PM CST FRI FEB 13 2015
A vigorous clipper system, currently diving across the Canadian
Prairies, will impact central and southeast Illinois on Saturday.
While the center of the surface low and better moisture will pass
well north/east of the forecast area, the gusty winds associated
with the system and cold temperatures in its wake will be featured
prominently across the area. The trailing cold front will dive
across the area early Saturday, with temperatures falling through
most of the day. There will be minimal moisture for the front to
work with as it dives through the area, but it should still be able
to squeeze out a few snow showers or flurries as forecast soundings
suggest ice crystals will be present. Still looking like a a Wind
Chill Advisory will be needed later Saturday night into Sunday
morning across the far northern portion of the forecast area,
especially along/north of the I-74 corridor. Even in areas where
advisory criteria will not be specifically met, it will be bitterly
cold Saturday night into Sunday.
Another wave will dive toward the area by late Sunday into early
Monday, but this one is progged to come ashore along the Pacific
Northwest. As such, the best forcing/snow chances with this system
should stay just to our south. That being said, at least the
southern fringe of the forecast area is in line to be impacted by
some jet/frontogenetical forcing associated with this wave. Still
expect most of the forecast area to be missed by this wave, but snow
accumulations as high an inch or two could be seen south of I-70.
The additional energy that follows the lead Pacific wave is now
expected to stay well south of the forecast area Monday/Tuesday as
the North American trof broadens to encompass much more of the
continent. No additional disturbances of consequence are currently
expected for the remainder of the forecast period. Temperatures will
remain below to well below normal.
&&
.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
ISSUED AT 1110 PM CST FRI FEB 13 2015
Low VFR cigs have dominated this evening and expect that to
continue until around 09z when a frontal boundary will approach
the area with occasional MVFR cigs with scattered snow showers.
At this point, it appears the better threat for a more organized
band of light snow will be over west central thru southeast IL
in the 11z-16z time frame where cigs and vsbys may drop briefly
to IFR. May see several narrow but intense bands of snow showers
develop towards dawn and track quickly from northwest to southeast.
Just where these narrow bands will setup and which TAF site they
will affect is still not that clear cut at this time. Will add
a tempo group for SPI and DEC for now and see how the band to our
northwest eventually sets up to see if we need to add lower cigs
and vsbys further north late tonight as well. Not looking at much
in the way of any accumulations with around a half inch possible in
a few locations tomorrow morning.
Any snow showers and lower vsbys/cigs will quickly move from
northwest to southeast during the morning and be out of the TAF
area by 18z with some scattered stratocumulus developing in the
strong cold advection pattern Saturday afternoon. Southwest winds
tonight of 10 to 15 kts will shift into the northwest by 11z
in PIA and by 14z in CMI. Look for a rapid increase in wind
speeds tomorrow morning with prevailing speeds of 15 to 25 kts
with gusts as high as 35 kts at times tomorrow morning into the
mid afternoon hours of Saturday before we see the winds gradually
diminish towards sunset Saturday evening.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Smith
SHORT TERM...Barnes
LONG TERM...Bak
AVIATION...Smith
AREA FORECAST DISCUSSION
NWS GOODLAND KS
400 PM MST SAT FEB 14 2015
.SHORT TERM...(THIS AFTERNOON THROUGH SUNDAY)
ISSUED AT 153 PM MST SAT FEB 14 2015
LATEST WV IMAGERY AND RAP H5 ANALYSIS SHOWS 499 DM UPPER LOW
CENTERED OVER THE EASTERN GREAT LAKES REGION. NW FLOW IS IN PLACE
ACROSS THE PLAINS, WITH A SHORTWAVE TROUGH MOVING INTO THE
NORTHERN PLAINS FROM CANADA. AT THE SURFACE A COLD FRONT IS IN THE
PROCESS OF MOVING ACROSS OUR CWA...AND IS CURRENTLY WEST OF KGLD
NEAR THE COLORADO BORDER...EXTENDING SOUTH JUST EAST OF KDDC.
THIS FRONT WILL CONTINUE TO TRANSITION WESTWARD THROUGH THE LATE
AFTERNOON AND EVENING...BEFORE STALLING IN EASTERN COLORADO (WEST
OF OUR CWA). CAA WILL CONTINUE THROUGH THE OVERNIGHT PERIOD WITH
MUCH COLDER TEMPS CONTINUING THROUGH THE DAY SUNDAY. THERE MAY BE
A PERIOD OF RETURN FLOW AND CLEARING IN SKY COVER FROM THE
SOUTHWEST...WHERE HIGHS SUNDAY MAY WARM INTO THE 40S. LOW-MID
CLOUDS MAY HOLD ON ACROSS THE EAST WHERE TEMPS MAY STRUGGLE TO
WARM ABOVE FREEZING SUNDAY AFTERNOON. NAM/SREF/RAP/HRRR CONTINUE
TO SHOW BL MOISTURE POOLING ALONG FRONTAL ZONE IN EASTERN COLORADO
WHICH COULD SUPPORT ADDITIONAL STRATUS OR FOG DEVELOPMENT. WE MAY
BE WELL MIXED ENOUGH THAT SIGNIFICANT VIS RESTRICTIONS WOULD NOT
BE AN ISSUE...AND GUIDANCE CURRENTLY KEEPS VIS ABOVE 3SM. I LEFT
PATCHY FREEZING FOG MENTION IN THE WEST...BUT NOT A LOT OF
CONFIDENCE.
SHORTWAVE TROUGH MOVES OVER THE REGION WITH SECOND ROUND OF CAA
ARRIVING BY LATE AFTERNOON. MAIN AREA OF FORCING WILL BE ASSOCIATE
WITH LOBE OF VORTICITY/ELEVATED BAROCLINIC ZONE WHICH CURRENT
TIMING FAVORS LATE AFTERNOON IN THE NORTH. MADE ADJUSTMENTS TO
BLEND WITH EVENING PERIOD AND SHOW THIS TRANSITION. ANY PRECIP IN
THE AFTERNOON WILL LIKELY BE MORE OF A RAIN/SNOW MIX BASED ON TEMP
PROFILES/WBZ HEIGHTS.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 159 PM MST SAT FEB 14 2015
FOR THE EXTENDED PERIOD...THE H5 RIDGE WHICH HAD BEEN OVER THE
WESTERN HALF OF THE COUNTRY OVER THE PAST SEVERAL DAYS...WILL NOW
SHIFT FURTHER WEST FOR THE UPCOMING WEEK...MAINLY SETTING UP ALONG
THE WEST COAST. THIS IN TURN WILL ALLOW A BROAD...DEEP H5 LOW TO
ENCOMPASS ALMOST 2/3RDS OF THE COUNTRY. DURING THE COURSE OF THE
UPCOMING WEEK...THE TRI STATE REGION WILL SEE A COUPLE OF SHORTWAVES
MOVING ALONG THE BASE OF THE UPPER LOW...GIVING THE CWA A CHANCE FOR
SOME NEEDED PRECIPITATION.
FIRST SYSTEM WILL MOVE SOUTH THRU THE ROCKIES LATE SUNDAY NIGHT INTO
MONDAY NIGHT...FOLLOWED BY A WEAKER SECONDARY SYSTEM ON TUESDAY. A
STRONG SURFACE RIDGE WILL ACCOMPANY THE FIRST SHORTWAVE...EDGING
DOWN THE EAST SIDE OF THE ROCKIES IN TANDEM WITH THE SHORTWAVE. THIS
IS GOING TO PUT AN EASTERLY FETCH ACROSS THE AREA...WITH SOME
UPSLOPE POTENTIAL FOR WESTERN ZONES AS SYSTEM SLIDES THRU THE AREA.
WILL BE CONTINUING AS A RESULT THE SNOWFALL GRADIENT FROM PREVIOUS
FORECAST...WITH HIGHEST POTENTIAL OVER WESTERN ZONES...ESPECIALLY
FOR EASTERN COLORADO. MODEL DIFFERENCE IN AMT OF QPF POTENTIAL FOR
THIS SYSTEM. THINKING UPSLOPE/OROGRAPHIC EFFECTS WILL HAVE BEST
CHANCE FOR SNOW ACCUM IN AFOREMENTIONED AREAS AT 1-2" WITH 0.5-1"
FOR EASTERN ZONES. SECOND SHORTWAVE PASSES THRU CENTRAL KANSAS ON
TUESDAY WITH EASTERN ZONES IN CWA GETTING CLIPPED AS IT SWINGS THRU.
WILL GO WITH A SLIGHT CHANCE FOR -RW/-SW...WITH LITTLE TO NO ACCUM
EXPECTED.
DRY CONDITIONS EXPECTED TUESDAY NIGHT THRU THURSDAY NIGHT WITH HIGH
PRESSURE MAIN WEATHER FEATURE OVER THE CENTRAL PLAINS...AND LEE-SIDE
TROUGH FORMATION OVER THE EASTERN SIDE OF THE ROCKIES. GOING INTO
FRIDAY AND NEXT SATURDAY...GFS/ECMWF DO DIFFER ON TIMING(AS MUCH AS
12 HRS) OF NEXT SHORTWAVE TO DIG SOUTH THRU THE ROCKIES AND ACROSS
THE CENTRAL PLAINS. CONSENSUS IS TO KEEP SLIGHT CHANCE POPS IN FOR
NOW. TEMPS ARE WARM ENOUGH DURING THE DAYTIME HOURS TO SUPPORT RW
MIXING IN WITH -SW...BUT -SW AT NIGHT.
TEMPERATURES IN THE EXTENDED WILL NEAR NORMAL NUMBERS EARLY IN THE
FORECAST WITH THE ARRIVAL OF CAA WITH MONDAY SHORTWAVE...THEN
INCREASING TO ABOVE NORMAL AS RIDGE SETS UP TO EAST THRU
MIDWEEK...THEN BACK DOWN TO NEAR NORMAL BY END OF WEEK WITH ARRIVAL
OF NEXT SHORTWAVE. OVERALL HIGHS WILL MAINLY IN THE 40S WITH 50S
POSSIBLE FRIDAY...AND OVERNIGHT LOWS WILL MAINLY RANGE IN THE TEENS
WITH SOME L20S BY END OF WEEK TIMEFRAME. SOME WIND GUSTS COULD REACH
INTO THE 15-25MPH RANGE WITH GRADIENT BEHIND EACH SUBSEQUENT
SHORTWAVE PASSAGE.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 400 PM MST SAT FEB 14 2015
KGLD...STRATUS AND MVFR CIGS PER SATELLITE IMAGERY AND RUC
950-925MB RH IS FORECAST TO BE JUST EAST OF THE TERMINAL AT TAF
ISSUANCE THEN MOVING WEST ACROSS THE TERMINAL IN THE 00Z-04Z
TIMEFRAME BRINGING MVFR CIGS WITH WINDS FROM THE EAST-SOUTHEAST
GUSTING 20-25KTS. IN THE 05Z- 06Z PERIOD BEST MOISTURE IN THIS
LAYER OVER FAR EASTERN COLORADO AND VFR CONDITIONS SHOULD RETURN
WITH SOUTHEAST WINDS JUST UNDER 12KTS. THESE WINDS ARE EXPECTED TO
CONTINUE THROUGH 15Z WITH PERHAPS SOME SCATTERED CLOUDS IN THE
MVFR CATEGORY BUT MOSTLY IN THE MID CLOUD CATEGORY. AROUND 16Z
WINDS SHIFT TO THE NORTH UNDER 10KTS INCREASING A BIT TOWARD 12KTS
FROM THE NORTHEAST IN THE 20Z-22Z TIMEFRAME BEFORE FALLING BELOW
10KTS BY 23Z. STILL CANT RULE OUT MVFR CIGS PER MODEL RH CROSS-
SECTIONS BUT FOR NOW WILL KEEP THOSE CLOUDS VFR WITH CIGS LOWERING
TOWARD 5K FT AT THE END OF THE PERIOD. NO PRECIPITATION CURRENTLY
EXPECTED. WILL HAVE TO MONITOR FOR FOG THREAT IN THE 06Z-15Z
TIMEFRAME AS WELL.
KMCK...STRATUS AND MVFR CIGS PER SATELLITE IMAGERY CURRENTLY OVER
THE TERMINAL AND RUC 950-850MB RH IS FORECAST TO SLOWLY MOVE WEST
AND AWAY FROM THE TERMINAL WITHIN THE NEXT HOUR OR TWO WITH WINDS
FROM THE EAST AROUND 13KTS. AROUND 06Z WINDS FALL BELOW 12KTS FROM
THE SOUTHEAST WITH SCATTERED CLOUDS IN MVFR CATEGORY AND A DECK
AROUND 15K FT. WINDS VEER TO THE SOUTH AND DECREASE TOWARD 5KTS
AROUND 15Z WITH CIGS LOWERING BUT REMAINING VFR. WIND SHIFT MOVES
THROUGH AROUND 21Z WITH NORTHWEST WINDS UNDER 10KTS THEN NORTHEAST
AT SIMILAR SPEEDS AROUND 23Z. NO PRECIPITATION CURRENTLY EXPECTED.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...JN
AVIATION...99
AREA FORECAST DISCUSSION
NWS GOODLAND KS
159 PM MST SAT FEB 14 2015
.SHORT TERM...(THIS AFTERNOON THROUGH SUNDAY)
ISSUED AT 153 PM MST SAT FEB 14 2015
LATEST WV IMAGERY AND RAP H5 ANALYSIS SHOWS 499 DM UPPER LOW
CENTERED OVER THE EASTERN GREAT LAKES REGION. NW FLOW IS IN PLACE
ACROSS THE PLAINS, WITH A SHORTWAVE TROUGH MOVING INTO THE
NORTHERN PLAINS FROM CANADA. AT THE SURFACE A COLD FRONT IS IN THE
PROCESS OF MOVING ACROSS OUR CWA...AND IS CURRENTLY WEST OF KGLD
NEAR THE COLORADO BORDER...EXTENDING SOUTH JUST EAST OF KDDC.
THIS FRONT WILL CONTINUE TO TRANSITION WESTWARD THROUGH THE LATE
AFTERNOON AND EVENING...BEFORE STALLING IN EASTERN COLORADO (WEST
OF OUR CWA). CAA WILL CONTINUE THROUGH THE OVERNIGHT PERIOD WITH
MUCH COLDER TEMPS CONTINUING THROUGH THE DAY SUNDAY. THERE MAY BE
A PERIOD OF RETURN FLOW AND CLEARING IN SKY COVER FROM THE
SOUTHWEST...WHERE HIGHS SUNDAY MAY WARM INTO THE 40S. LOW-MID
CLOUDS MAY HOLD ON ACROSS THE EAST WHERE TEMPS MAY STRUGGLE TO
WARM ABOVE FREEZING SUNDAY AFTERNOON. NAM/SREF/RAP/HRRR CONTINUE
TO SHOW BL MOISTURE POOLING ALONG FRONTAL ZONE IN EASTERN COLORADO
WHICH COULD SUPPORT ADDITIONAL STRATUS OR FOG DEVELOPMENT. WE MAY
BE WELL MIXED ENOUGH THAT SIGNIFICANT VIS RESTRICTIONS WOULD NOT
BE AN ISSUE...AND GUIDANCE CURRENTLY KEEPS VIS ABOVE 3SM. I LEFT
PATCHY FREEZING FOG MENTION IN THE WEST...BUT NOT A LOT OF
CONFIDENCE.
SHORTWAVE TROUGH MOVES OVER THE REGION WITH SECOND ROUND OF CAA
ARRIVING BY LATE AFTERNOON. MAIN AREA OF FORCING WILL BE ASSOCIATE
WITH LOBE OF VORTICITY/ELEVATED BAROCLINIC ZONE WHICH CURRENT
TIMING FAVORS LATE AFTERNOON IN THE NORTH. MADE ADJUSTMENTS TO
BLEND WITH EVENING PERIOD AND SHOW THIS TRANSITION. ANY PRECIP IN
THE AFTERNOON WILL LIKELY BE MORE OF A RAIN/SNOW MIX BASED ON TEMP
PROFILES/WBZ HEIGHTS.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 159 PM MST SAT FEB 14 2015
FOR THE EXTENDED PERIOD...THE H5 RIDGE WHICH HAD BEEN OVER THE
WESTERN HALF OF THE COUNTRY OVER THE PAST SEVERAL DAYS...WILL NOW
SHIFT FURTHER WEST FOR THE UPCOMING WEEK...MAINLY SETTING UP ALONG
THE WEST COAST. THIS IN TURN WILL ALLOW A BROAD...DEEP H5 LOW TO
ENCOMPASS ALMOST 2/3RDS OF THE COUNTRY. DURING THE COURSE OF THE
UPCOMING WEEK...THE TRI STATE REGION WILL SEE A COUPLE OF SHORTWAVES
MOVING ALONG THE BASE OF THE UPPER LOW...GIVING THE CWA A CHANCE FOR
SOME NEEDED PRECIPITATION.
FIRST SYSTEM WILL MOVE SOUTH THRU THE ROCKIES LATE SUNDAY NIGHT INTO
MONDAY NIGHT...FOLLOWED BY A WEAKER SECONDARY SYSTEM ON TUESDAY. A
STRONG SURFACE RIDGE WILL ACCOMPANY THE FIRST SHORTWAVE...EDGING
DOWN THE EAST SIDE OF THE ROCKIES IN TANDEM WITH THE SHORTWAVE. THIS
IS GOING TO PUT AN EASTERLY FETCH ACROSS THE AREA...WITH SOME
UPSLOPE POTENTIAL FOR WESTERN ZONES AS SYSTEM SLIDES THRU THE AREA.
WILL BE CONTINUING AS A RESULT THE SNOWFALL GRADIENT FROM PREVIOUS
FORECAST...WITH HIGHEST POTENTIAL OVER WESTERN ZONES...ESPECIALLY
FOR EASTERN COLORADO. MODEL DIFFERENCE IN AMT OF QPF POTENTIAL FOR
THIS SYSTEM. THINKING UPSLOPE/OROGRAPHIC EFFECTS WILL HAVE BEST
CHANCE FOR SNOW ACCUM IN AFOREMENTIONED AREAS AT 1-2" WITH 0.5-1"
FOR EASTERN ZONES. SECOND SHORTWAVE PASSES THRU CENTRAL KANSAS ON
TUESDAY WITH EASTERN ZONES IN CWA GETTING CLIPPED AS IT SWINGS THRU.
WILL GO WITH A SLIGHT CHANCE FOR -RW/-SW...WITH LITTLE TO NO ACCUM
EXPECTED.
DRY CONDITIONS EXPECTED TUESDAY NIGHT THRU THURSDAY NIGHT WITH HIGH
PRESSURE MAIN WEATHER FEATURE OVER THE CENTRAL PLAINS...AND LEE-SIDE
TROUGH FORMATION OVER THE EASTERN SIDE OF THE ROCKIES. GOING INTO
FRIDAY AND NEXT SATURDAY...GFS/ECMWF DO DIFFER ON TIMING(AS MUCH AS
12 HRS) OF NEXT SHORTWAVE TO DIG SOUTH THRU THE ROCKIES AND ACROSS
THE CENTRAL PLAINS. CONSENSUS IS TO KEEP SLIGHT CHANCE POPS IN FOR
NOW. TEMPS ARE WARM ENOUGH DURING THE DAYTIME HOURS TO SUPPORT RW
MIXING IN WITH -SW...BUT -SW AT NIGHT.
TEMPERATURES IN THE EXTENDED WILL NEAR NORMAL NUMBERS EARLY IN THE
FORECAST WITH THE ARRIVAL OF CAA WITH MONDAY SHORTWAVE...THEN
INCREASING TO ABOVE NORMAL AS RIDGE SETS UP TO EAST THRU
MIDWEEK...THEN BACK DOWN TO NEAR NORMAL BY END OF WEEK WITH ARRIVAL
OF NEXT SHORTWAVE. OVERALL HIGHS WILL MAINLY IN THE 40S WITH 50S
POSSIBLE FRIDAY...AND OVERNIGHT LOWS WILL MAINLY RANGE IN THE TEENS
WITH SOME L20S BY END OF WEEK TIMEFRAME. SOME WIND GUSTS COULD REACH
INTO THE 15-25MPH RANGE WITH GRADIENT BEHIND EACH SUBSEQUENT
SHORTWAVE PASSAGE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1025 AM MST SAT FEB 14 2015
ACTIVELY MONITORING COLD FRONT JUST WEST OF KMCK...AND IFR STRATUS
JUST NORTHEAST OF THE KMCK TERMINAL. EXPECT PREVAILING MVFR AND
AT LEAST TEMPO IFR TO DEVELOP AT KMCK BY VALID TAF TIME (06Z)
BASED ON OBS/TIMING OF VIS SATELLITE. DIFFUSE BACK AND SOUTHERN
EDGE OF STRATUS MATCHES WITH GENERAL TRENDS FROM SHORT RANGE
GUIDANCE...WHICH SHOULD ALLOW FOR VFR CONDITIONS TO PREVAIL AT
KGLD THIS AFTERNOON THOUGH I COULDNT RULE OUT A BRIEF PERIOD OF
IFR CIGS AT SOME POINT. CONFIDENCE JUST TOO LOW TO ADD AT THIS
TIME. FRONT WILL STALL ACROSS EASTERN COLORADO BY THIS
EVENING...WITH BL MOISTURE POOLING JUST EAST OF THIS. THIS SHOULD
SUPPORT LIGHT FOG DEVELOPMENT AND LOWERING CIGS LATER THIS EVENING
THROUGH SUNDAY MORNING AT KGLD. CURRENTLY EXPECT LOWER CIGS/VIS TO
REMAIN IN EASTERN COLORADO...SO HAVE KEPT MVFR IN KGLD AFTER 03Z.
GUSTY EAST-NORTHEAST WINDS WILL DEVELOP THIS AFTERNOON AT BOTH
TERMINALS BEHIND COLD FRONT...DIMINISHING THIS EVENING/OVERNIGHT.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...JN
AVIATION...DR
AREA FORECAST DISCUSSION
NWS GOODLAND KS
155 PM MST SAT FEB 14 2015
.SHORT TERM...(THIS AFTERNOON THROUGH SUNDAY)
ISSUED AT 153 PM MST SAT FEB 14 2015
LATEST WV IMAGERY AND RAP H5 ANALYSIS SHOWS 499 DM UPPER LOW
CENTERED OVER THE EASTERN GREAT LAKES REGION. NW FLOW IS IN PLACE
ACROSS THE PLAINS, WITH A SHORTWAVE TROUGH MOVING INTO THE
NORTHERN PLAINS FROM CANADA. AT THE SURFACE A COLD FRONT IS IN THE
PROCESS OF MOVING ACROSS OUR CWA...AND IS CURRENTLY WEST OF KGLD
NEAR THE COLORADO BORDER...EXTENDING SOUTH JUST EAST OF KDDC.
THIS FRONT WILL CONTINUE TO TRANSITION WESTWARD THROUGH THE LATE
AFTERNOON AND EVENING...BEFORE STALLING IN EASTERN COLORADO (WEST
OF OUR CWA). CAA WILL CONTINUE THROUGH THE OVERNIGHT PERIOD WITH
MUCH COLDER TEMPS CONTINUING THROUGH THE DAY SUNDAY. THERE MAY BE
A PERIOD OF RETURN FLOW AND CLEARING IN SKY COVER FROM THE
SOUTHWEST...WHERE HIGHS SUNDAY MAY WARM INTO THE 40S. LOW-MID
CLOUDS MAY HOLD ON ACROSS THE EAST WHERE TEMPS MAY STRUGGLE TO
WARM ABOVE FREEZING SUNDAY AFTERNOON. NAM/SREF/RAP/HRRR CONTINUE
TO SHOW BL MOISTURE POOLING ALONG FRONTAL ZONE IN EASTERN COLORADO
WHICH COULD SUPPORT ADDITIONAL STRATUS OR FOG DEVELOPMENT. WE MAY
BE WELL MIXED ENOUGH THAT SIGNIFICANT VIS RESTRICTIONS WOULD NOT
BE AN ISSUE...AND GUIDANCE CURRENTLY KEEPS VIS ABOVE 3SM. I LEFT
PATCHY FREEZING FOG MENTION IN THE WEST...BUT NOT A LOT OF
CONFIDENCE.
SHORTWAVE TROUGH MOVES OVER THE REGION WITH SECOND ROUND OF CAA
ARRIVING BY LATE AFTERNOON. MAIN AREA OF FORCING WILL BE ASSOCIATE
WITH LOBE OF VORTICITY/ELEVATED BAROCLINIC ZONE WHICH CURRENT
TIMING FAVORS LATE AFTERNOON IN THE NORTH. MADE ADJUSTMENTS TO
BLEND WITH EVENING PERIOD AND SHOW THIS TRANSITION. ANY PRECIP IN
THE AFTERNOON WILL LIKELY BE MORE OF A RAIN/SNOW MIX BASED ON TEMP
PROFILES/WBZ HEIGHTS.
.LONG TERM...(TUESDAY THROUGH FRIDAY)
ISSUED AT 214 AM MST SAT FEB 14 2015
OVERALL...MOSTLY DRY FORECAST ISSUED FOR THIS EXTENDED CYCLE WITH A
GRADUAL WARMING TREND POSSIBLE BY MIDDLE OF NEXT WEEK. MOST ACTIVE
WEATHER DAY...IN TERMS OF GUSTY NORTHWEST WINDS AND POSSIBLE
CONVECTIVE RAIN/SNOW SHOWERS...FALLS ON TUESDAY WITH QUIET WEATHER
WEDNESDAY ON. MODEL DISAGREEMENT BECOMES A PROBLEM BY END OF NEXT
WEEK AS THE GFS BRINGS ANOTHER ARCTIC AIRMASS SOUTH FRIDAY/SATURDAY.
MEANWHILE...ECMWF HOLDS ARCTIC AIR BACK UNTIL SATURDAY/SUNDAY. THERE
COULD BE ANOTHER PRECIPITATION CHANCE FRIDAY NIGHT-SATURDAY NIGHT
BUT MODEL DISAGREEMENT DOESN`T INSTILL MUCH CONFIDENCE. REST OF THIS
DISCUSSION FOCUSES ON TUESDAY/WEDNESDAY FORECAST.
TUESDAY...MOST ACTIVE WEATHER DAY OF THE EXTENDED FORECAST IS
ANTICIPATED. A FEW THINGS WORKING FOR US HERE...STRONG REGIME OF
NORTHWEST FLOW WINDS ALOFT AND A SHORTWAVE TROUGH PASSING OVER THE
HIGH PLAINS. 700 MB JET OF WINDS SLIDES INTO THE AREA TUESDAY WITH
STRENGTHENING LIKELY THROUGH TUESDAY NIGHT. FAVORABLE LAPSE RATES
AND SOUNDING PROFILES INDICATE A MIXED LAYER UP TO AROUND 700 MB SO
WE SHOULD BE ABLE TO MIX STRONGER GUSTS DOWN TUESDAY. PRESENT
EXPECTATIONS ARE FOR A WINDY DAY BUT WILL NEED TO WATCH 700 MB JET
STRENGTH. GFS/ECMWF/CANADIAN ARE ALL IN AGREEMENT ON 700 MB WINDS
WHICH COULD MIX DOWN GUSTS 35-45 KTS. WILL HOLD OFF ON ADVERTISING
WINDS THAT STRONG FOR NOW. WILL NEED TO WATCH TUESDAY CLOSELY AS
THIS PATTERN TYPICALLY FAVORS HIGH WIND EVENTS OVER THE HIGH PLAINS.
IN ADDITION TO WINDS...THE SHORTWAVE COMING THROUGH SHOULD ALLOW FOR
CONVECTIVE SHOWER DEVELOPMENT. SOUNDINGS...850-500MB LAPSE RATES AND
SOME SLIGHT MUCAPE INDICATE AN UNSTABLE ATMOSPHERE. INCREASED AREA
OF SLIGHT CHANCE POPS GIVEN FROM THE EXTENDED FORECAST TO ACCOUNT
FOR THIS THINKING. THIS PATTERN IS FAIRLY COMMON FOR CONVECTIVE COOL-
SEASON SHOWERS. CURRENT FORECAST ATMOSPHERIC PROFILE SUGGESTS THAT
SNOW SHOULD BE THE PREDOMINANT PRECIPITATION TYPE. FURTHER SOUTH
WHERE WARMER TEMPERATURES ARE FORECAST...MENTIONED A RAIN/SNOW MIX.
WEDNESDAY...STRONG 700 MB JET REMAINS OVERHEAD. GRADUAL WEAKENING OF
THE JET IS ANTICIPATED. ONE CONCERN WITH THIS DAY IS THERE SHOULD BE
50-60 KTS OF WIND AT 700 MB WHICH RAISES A RED FLAG FOR POTENTIAL
HIGH WIND EVENT. HOWEVER...SOUNDINGS AND LAPSE RATES DO NOT SUPPORT
THESE GUSTS REACHING THE GROUND. IN FACT...INDICATIONS ARE FAIRLY
LIGHT WINDS...LESS THAN 25 MPH...ARE MORE LIKELY. THEREFORE...DO NOT
THINK WEDNESDAYS WINDS ARE ANYTHING TO WORRY ABOUT AT THE PRESENT
TIME.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1025 AM MST SAT FEB 14 2015
ACTIVELY MONITORING COLD FRONT JUST WEST OF KMCK...AND IFR STRATUS
JUST NORTHEAST OF THE KMCK TERMINAL. EXPECT PREVAILING MVFR AND
AT LEAST TEMPO IFR TO DEVELOP AT KMCK BY VALID TAF TIME (06Z)
BASED ON OBS/TIMING OF VIS SATELLITE. DIFFUSE BACK AND SOUTHERN
EDGE OF STRATUS MATCHES WITH GENERAL TRENDS FROM SHORT RANGE
GUIDANCE...WHICH SHOULD ALLOW FOR VFR CONDITIONS TO PREVAIL AT
KGLD THIS AFTERNOON THOUGH I COULDNT RULE OUT A BRIEF PERIOD OF
IFR CIGS AT SOME POINT. CONFIDENCE JUST TOO LOW TO ADD AT THIS
TIME. FRONT WILL STALL ACROSS EASTERN COLORADO BY THIS
EVENING...WITH BL MOISTURE POOLING JUST EAST OF THIS. THIS SHOULD
SUPPORT LIGHT FOG DEVELOPMENT AND LOWERING CIGS LATER THIS EVENING
THROUGH SUNDAY MORNING AT KGLD. CURRENTLY EXPECT LOWER CIGS/VIS TO
REMAIN IN EASTERN COLORADO...SO HAVE KEPT MVFR IN KGLD AFTER 03Z.
GUSTY EAST-NORTHEAST WINDS WILL DEVELOP THIS AFTERNOON AT BOTH
TERMINALS BEHIND COLD FRONT...DIMINISHING THIS EVENING/OVERNIGHT.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...RRH
AVIATION...DR
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
222 AM CST SAT FEB 14 2015
...UPDATE TO LONG TERM...
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 147 AM CST SAT FEB 14 2015
MODELS THIS MORNING WERE IN GOOD AGREEMENT WITH A COLD FRONT
CROSSING SOUTHWEST KANSAS BETWEEN 15Z AND 12Z AS AN UPPER LEVEL
TROUGH CROSSES THE GREAT LAKES REGION. NAM, GFS, RAP, AND HRRR
WERE ALSO IN GOOD AGREEMENT WITH THE COLDER AIR IN THE LOWER
LEVELS INVADING WESTERN KANSAS BEHIND THIS COLD FRONT DURING THE
LATE MORNING AND AFTERNOON. SOME LOW CLOUDS WILL ALSO BE SPREADING
SOUTHWEST INTO PORTIONS OF WESTERN KANSAS DURING THE AFTERNOON AND
EVENING HOURS BASED THE 900MB TO 875MB LEVEL RH FIELD AND 00Z NAM
BUFR SOUNDINGS. GIVEN THIS INCREASING CLOUDS, ESPECIALLY IN THE
NORTH, AND COOLING TEMPERATURES FORECAST IN THE LOWER LEVELS BY
ALL THE MODELS WILL STAY CLOSE TO THE PREVIOUS FORECAST WITH AN
EARLY HIGH IN THE UPPER 30S ACROSS NORTH CENTRAL KANSAS. 18Z AND
21Z SATURDAY NAM BUFR SOUNDINGS SUPPORT THE POTENTIAL FOR HIGHS
APPROACHING 70 DEGREES IN EXTREME SOUTHWEST KANSAS. HIGH
TEMPERATURES TODAY BETWEEN THESE TWO EXTREMES ARE MORE UNCERTAIN
GIVEN THE TIMING ON THE FRONTAL PASSAGE AND HOW QUICKLY THE COLD
AIR ADVECTION DEVELOPS IS BEHIND THIS COLD FRONT. GUSTY WINDS OF
20 TO 25 MPH WILL ALSO BE LIKELY THIS AFTERNOON BEHIND THIS COLD
FRONT BASED ON MEAN MIXED LAYER WINDS FROM THE NAM AND GFS BETWEEN
18Z SATURDAY AND 00Z SUNDAY.
TONIGHT THE 900 TO 875MB MOISTURE WILL SHIFT EAST TO THE COLORADO
BORDER AND AN EASTERLY UPSLOPE FLOW WILL IMPROVE ACROSS WESTERN
KANSAS. AT THIS TIME BASED ON VARIOUS MODEL SOUNDINGS IN WEST
CENTRAL KANSAS THE DEPTH OF THIS MOIST LAYER WILL NOT BE DEEP
ENOUGH TO SUPPORT ANY LIGHT PRECIPITATION DURING THE OVERNIGHT
HOURS. AFTER MIDNIGHT MID AND HIGH LEVEL MOISTURE WILL BEGIN TO
INCREASE ACROSS ALL OF WESTERN KANSAS AS AN UPPER LEVEL TROUGH
APPROACHES THE CENTRAL ROCKIES FROM THE NORTHWEST. THIS INCREASING
CLOUD MAY LIMIT HOW COLD TEMPERATURES WILL BY 12Z SUNDAY. AS A
RESULT WILL TREND OVERNIGHT LOWS TOWARD THE WARMER MET GUIDANCE
FOR OVERNIGHT LOWS.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 222 AM CST SAT FEB 14 2015
SUNDAY LOOKS TO BE A RATHER COLD DAY. THERE ARE SOME DIFFERENCES BETWEEN
THE ECMWF AND AND THE GFS. JUST FROM A PATTERN RECOGNITION STANDPOINT,
SUNDAY LOOKS TO BE AN UPSLOPE/STRATUS DAY. THE ECE GUIDANCE IS CONSIDERABLY
COLDER THAN THE MEX (30 VERSUS 41 FOR DDC FOR EXAMPLE). HAVE UNDERCUT
THE INHERITED MAXIMUM TEMPERATURE GRID BY SEVERAL DEGREES TO SIDE MORE
WITH THE ECMWF. TO ADD TO THE UNCERTAINTY, ENSEMBLE SPREAD ISN`T THAT
HELPFUL EITHER WITH A HIGH OF 41 TO A LOW OF 29. STILL, FORECAST SOUNDINGS
SHOW LOW LEVEL SATURATION AND THINK THAT THE GFS IS TRYING TO CLEAR
SKIES OUT QUICKER THAN WHAT NORMALLY OCCURS. THERE COULD BE SOME FLURRIES
SUNDAY EVENING ACROSS THE REGION AS AN 110 KT 250-HPA RIGHT ENTRANCE
REGION JET STREAK MOVES ACROSS. OTHER THAN THIS, DYNAMICS IS NOT PARTICULARLY
THAT IMPRESSIVE WITH A POSITIVELY TILTED SYNOPTIC SYSTEM. A BETTER CHANCE
OF SNOW FOR FAR SOUTHWEST KANSAS IS POSSIBLE MONDAY WITH BETTER UPSLOPE
FLOW AND A SUBTLE VORTMAX MOVING THROUGH AT THE BASE OF THE TROUGH.
WILL CONTINUE WITH CHANCE POPS FOR FAR SOUTHWEST KANSAS. THERE COULD
BE LIGHT SNOW ACCUMULATION BY THE TIME IT`S ALL SAID AND DONE WITH ACROSS
FAR SW KANSAS. HAVE JUST OVER AN INCH ACROSS MORTON COUNTY, BUT THIS
MIGHT BE PUSHING IT ON THE HIGH SIDE. THE GFS IS SLIGHTLY MORE EAST
WITH THE FRONTOGENETIC ZONE AND RESULTANT QPF THAN COMPARED TO THE ECMWF,
SO THERE IS STILL SOME UNCERTAINTY. MONDAYS HIGHS SHOULD TO BE A LITTLE
WARMER WITH DOWNSLOPE NORTHWESTERLY WINDS. BEYOND THAT, TEMPERATURES
WILL MODERATE SOMEWHAT, BUT STILL BE A LITTLE BELOW NORMAL. COULD SEE
RATHER PLEASANT TEMPERATURES BY THE END OF THE UPCOMING BUSINESS WEEK,
BUT CONFIDENCE IS PRETTY LOW. DOESN`T LOOK LIKE ANY SIGNIFICANT PRECIPITATION
ANYTIME SOON IN THE FORM OF RAIN AND/OR SNOW.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1119 PM CST FRI FEB 13 2015
NAM, RAP, AND HRRR WERE ALL IN DECENT AGREEMENT THIS MORNING WILL
MOVING A COLD FRONT ACROSS SOUTHWEST KANSAS BETWEEN 15Z AND 21Z
SATURDAY. AS THIS FRONT PASSES A SOUTHWEST/WESTERLY WIND AT 10
KNOTS OR LESS WILL SHIFT TO THE NORTHEAST AND THEN INCREASE TO
AROUND 20 KNOTS. AT THIS TIME FRONTAL PASSAGE IS EXPECTED AT HAYS
AROUND 15Z AND THEN AT DODGE CITY AND GARDEN CITY AROUND 18Z.
GUSTY WINDS BEHIND THIS FRONT WILL GRADUALLY VEER MORE EASTERLY BY
00Z SUNDAY AND AFTER 03Z SUNDAY DECREASE INTO THE 10 TO 15 KNOT
RANGE. NAM BUFR SOUNDINGS DOES INDICATED SOME INCREASING MOISTURE
IN THE 2000 TO 3000FT AGL LEVEL BEHIND THIS FRONT AFTER 18Z IN
MAINLY THE HAYS AREA SO A PERIOD OF MVFR CEILINGS IS ANTICIPATED
LATER TODAY IN NORTH CENTRAL KANSAS. ELSEWHERE VFR CONDITIONS ARE
EXPECTED THROUGH THE EARLY EVENING.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 58 15 29 20 / 0 0 10 10
GCK 58 16 32 21 / 0 0 10 20
EHA 69 21 41 25 / 0 0 10 20
LBL 66 18 34 22 / 0 10 10 20
HYS 39 12 28 19 / 0 0 10 10
P28 59 16 28 17 / 0 10 10 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BURGERT
LONG TERM...SUGDEN
AVIATION...BURGERT
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
148 AM CST SAT FEB 14 2015
...UPDATED SHORT TERM DISCUSSION...
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 147 AM CST SAT FEB 14 2015
MODELS THIS MORNING WERE IN GOOD AGREEMENT WITH A COLD FRONT
CROSSING SOUTHWEST KANSAS BETWEEN 15Z AND 12Z AS AN UPPER LEVEL
TROUGH CROSSES THE GREAT LAKES REGION. NAM, GFS, RAP, AND HRRR
WERE ALSO IN GOOD AGREEMENT WITH THE COLDER AIR IN THE LOWER
LEVELS INVADING WESTERN KANSAS BEHIND THIS COLD FRONT DURING THE
LATE MORNING AND AFTERNOON. SOME LOW CLOUDS WILL ALSO BE SPREADING
SOUTHWEST INTO PORTIONS OF WESTERN KANSAS DURING THE AFTERNOON AND
EVENING HOURS BASED THE 900MB TO 875MB LEVEL RH FIELD AND 00Z NAM
BUFR SOUNDINGS. GIVEN THIS INCREASING CLOUDS, ESPECIALLY IN THE
NORTH, AND COOLING TEMPERATURES FORECAST IN THE LOWER LEVELS BY
ALL THE MODELS WILL STAY CLOSE TO THE PREVIOUS FORECAST WITH AN
EARLY HIGH IN THE UPPER 30S ACROSS NORTH CENTRAL KANSAS. 18Z AND
21Z SATURDAY NAM BUFR SOUNDINGS SUPPORT THE POTENTIAL FOR HIGHS
APPROACHING 70 DEGREES IN EXTREME SOUTHWEST KANSAS. HIGH
TEMPERATURES TODAY BETWEEN THESE TWO EXTREMES ARE MORE UNCERTAIN
GIVEN THE TIMING ON THE FRONTAL PASSAGE AND HOW QUICKLY THE COLD
AIR ADVECTION DEVELOPS IS BEHIND THIS COLD FRONT. GUSTY WINDS OF
20 TO 25 MPH WILL ALSO BE LIKELY THIS AFTERNOON BEHIND THIS COLD
FRONT BASED ON MEAN MIXED LAYER WINDS FROM THE NAM AND GFS BETWEEN
18Z SATURDAY AND 00Z SUNDAY.
TONIGHT THE 900 TO 875MB MOISTURE WILL SHIFT EAST TO THE COLORADO
BORDER AND AN EASTERLY UPSLOPE FLOW WILL IMPROVE ACROSS WESTERN
KANSAS. AT THIS TIME BASED ON VARIOUS MODEL SOUNDINGS IN WEST
CENTRAL KANSAS THE DEPTH OF THIS MOIST LAYER WILL NOT BE DEEP
ENOUGH TO SUPPORT ANY LIGHT PRECIPITATION DURING THE OVERNIGHT
HOURS. AFTER MIDNIGHT MID AND HIGH LEVEL MOISTURE WILL BEGIN TO
INCREASE ACROSS ALL OF WESTERN KANSAS AS AN UPPER LEVEL TROUGH
APPROACHES THE CENTRAL ROCKIES FROM THE NORTHWEST. THIS INCREASING
CLOUD MAY LIMIT HOW COLD TEMPERATURES WILL BY 12Z SUNDAY. AS A
RESULT WILL TREND OVERNIGHT LOWS TOWARD THE WARMER MET GUIDANCE
FOR OVERNIGHT LOWS.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 223 PM CST FRI FEB 13 2015
RETROGRESSION OF THE UPPER LEVEL LONG WAVE PATTERN IS IN PROGRESS,
AND CONSIDERABLY COOLER WEATHER WILL RETURN TO THE CENTRAL PLAINS
AND PERSIST FOR THE REST OF FEBRUARY. WHEREAS THE FIRST PART OF THE
MONTH WAS CHARACTERIZED BY A RIDGE CENTERED 110-120W AND A PLUME OF
DOWNSLOPE-WARMED AIR IN THE PLAINS, THE REST OF THE MONTH IS LIKELY
TO BE CHARACTERIZED BY A LONG WAVE RIDGE CENTERED 120-130W AND ONLY
BRIEF PERIODS OF WARMING BETWEEN SURGES OF COLD AIR.
THE NUMERICAL MODELS ARE IN GOOD AGREEMENT ON EVOLUTION OF THE LARGE
SCALE FLOW, ALTHOUGH DIFFERENCES IN SYNOPTIC SCALE DETAILS BECOME
MORE EVIDENT BY LATE NEXT WEEK. THE ECMWF HAS TRENDED TOWARD THE
DRIER GFS SOLUTION FOR THE MINOR PRECIPITATION EVENT MONDAY AND
SEEMS REASONABLE. THE ECMWF IS SLOWER TO ERODE THE MODIFIED ARCTIC
AIR THAN THE GFS ON WEDNESDAY, AND THE GFS APPEARS TO GENERATE
EXCESSIVE LEE TROUGHING WITH STRONGLY MERIDIONAL FLOW. THE
DETERMINISTIC ECMWF SEEMS MORE REASONABLE BY THE MIDDLE OF NEXT
WEEK. THE ECMWF HAS MORE AMPLITUDE WITH THE UPPER LEVEL TROUGH THAT
REACHES THE WEST COAST THURSDAY THAN THE GFS AND BRINGS A MUCH
STRONGER TROUGH INTO THE SOUTHERN PLAINS FRIDAY NIGHT THAN DOES THE
GFS. MOST OF THE GFS ENSEMBLES MAINTAIN A SPLIT FLOW WITH A PORTION
OF THE TROUGH HANGING BACK IN THE SOUTHWESTERN UNITED STATES, AND
THE WEAKER GFS SOLUTION IS PREFERRED FOR NEXT WEEKEND.
THE COLD AIR MASS THAT WILL INVADE KANSAS SATURDAY AND SATURDAY
NIGHT WILL REMAIN ENTRENCHED IN THE CENTRAL PART OF THE COUNTRY
THROUGH WEDNESDAY. A MINOR UPPER LEVEL TROUGH NEAR 45N/145W THIS
AFTERNOON WILL PROGRESS THROUGH THE EASTERN PACIFIC RIDGE AND REACH
KANSAS ON SUNDAY. LOW LEVEL MOISTURE IN SOUTHWEST TEXAS WILL FLOW
NORTH OVER THE ARCTIC AIR AND SHOULD RESULT IN FORMATION OF
WIDESPREAD STRATUS SATURDAY NIGHT AND SUNDAY AS WINDS BECOME SOUTH
ABOVE THE ARCTIC AIR. MODEL SOUNDINGS SUGGEST THAT THE MOISTURE
LAYER WILL BE SHALLOW AND THAT HIGH DEWPOINT DEPRESSIONS WILL EXIST
BELOW THE MOIST LAYER. AS SUCH, THE POTENTIAL FOR FREEZING DRIZZLE
WITH THE LOW LEVEL ISENTROPIC LIFTING SEEMS MINIMAL IN WESTERN
KANSAS. THE STRATUS WILL BE SLOW TO DISSIPATE ON SUNDAY BUT LIKELY
WILL ERODE FROM WEST TO EAST AS LOW LEVEL WINDS BECOME MORE NORTH
FOLLOWING PASSAGE OF THE UPPER LEVEL TROUGH. THERE IS A CHANCE THAT
THERE COULD BE A FEW SNOW FLURRIES SUNDAY AFTERNOON WITH THE TROUGH,
BUT MODEL SOUNDINGS HAVE QUITE A BIT OF DRY AIR IN THE MID LEVELS TO
EVAPORATE MOST OF ANY PRECIPITATION THAT DEVELOPS.
TEMPERATURES SATURDAY NIGHT ARE SOMEWHAT PROBLEMATIC GIVEN THE COLD
AIR ADVECTION AND THE CLOUD COVER. THE REALLY COLD ARCTIC AIR WILL
REMAIN WELL EAST OF KANSAS, AND TEMPERATURES PROBABLY WILL NOT BE
ALL THAT FRIGID IN SOUTHWESTERN KANSAS. VALUES WERE ADJUSTED UP
SLIGHTLY. SUNDAY WILL BE COOL WITH CONSIDERABLE CLOUD COVER,
ESPECIALLY IN CENTRAL AND SOUTH CENTRAL KANSAS. THERE SHOULD BE
ENOUGH SUN TO ALLOW HIGHS IN THE LOW TO MID 40S IN FAR SOUTHWEST
KANSAS.
THE POTENTIAL FOR MEASURABLE PRECIPITATION WITH THE UPPER LEVEL
TROUGH THAT APPROACHES THE FOUR CORNERS AREA MONDAY EVENING IS NOT
THAT GREAT IN WESTERN KANSAS. UPWARD VERTICAL MOTION APPEARS TO BE
QUITE WEAK EAST OF THE COLORADO BORDER WITH WEAK MID LEVEL
FRONTOGENESIS AND MARGINAL DIFFERENTIAL POSITIVE VORTICITY ADVECTION
WITH THE DIGGING UPPER LEVEL TROUGH. SNOWFALL TOTALS WILL BE QUITE
LIGHT, AND ANYTHING MORE THAN AN INCH PROBABLY WILL BE RESTRICTED
TO MORTON COUNTY.
A STRONG JET STREAK IN THE NORTHWEST FLOW WILL MOVE INTO WESTERN
KANSAS TUESDAY, AND DIVERGENCE IN THE EXIT REGION OF THE JET STREAK
MAY PRODUCE ENOUGH VERTICAL MOTION FOR A FEW SNOW FLURRIES TUESDAY
AFTERNOON. SOME EROSION OF THE ARCTIC AIR WILL OCCUR IN FAR WESTERN
KANSAS WEDNESDAY, BUT THE GFS APPEARS TOO QUICK TO ERODE THE COLD
AIR. THE COLD AIR WILL SLOSH BACK WEST WEDNESDAY NIGHT AS YET
ANOTHER UPPER LEVEL TROUGH DROPS INTO THE UPPER MIDWEST. THE UPPER
LEVEL FLOW WILL BECOME LESS MERIDIONAL THURSDAY AND FRIDAY AS A
TROUGH MOVES THROUGH THE LONG WAVE RIDGE INTO THE WESTERN UNITED
STATES, AND DOWNSLOPE FLOW SHOULD SCOUR OUT THE REMNANTS OF THE
ARCTIC AIR THURSDAY AFTERNOON AND NIGHT. COOLER AIR WILL RETURN NEXT
WEEKEND, BUT THE DETAILS ARE UNCERTAIN. IF THE UPPER LEVEL TROUGH
COMES OUT IN ONE PIECE LIKE THE ECMWF ADVERTISES, THERE WILL BE A
CHANCE FOR LIGHT PRECIPITATION IN WESTERN KANSAS; HOWEVER, THE
WEAKER GFS SOLUTION SEEMS MORE REASONABLE.
ADDITIONAL SURGES OF COLD AIR ARE LIKELY EVERY FEW DAYS UNTIL A MORE
ZONAL FLOW REGIME RETURNS IN EARLY MARCH. THERE IS LITTLE INDICATION
THAT SIGNIFICANT PRECIPITATION IS LIKELY IN THE NEAR FUTURE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1119 PM CST FRI FEB 13 2015
NAM, RAP, AND HRRR WERE ALL IN DECENT AGREEMENT THIS MORNING WILL
MOVING A COLD FRONT ACROSS SOUTHWEST KANSAS BETWEEN 15Z AND 21Z
SATURDAY. AS THIS FRONT PASSES A SOUTHWEST/WESTERLY WIND AT 10
KNOTS OR LESS WILL SHIFT TO THE NORTHEAST AND THEN INCREASE TO
AROUND 20 KNOTS. AT THIS TIME FRONTAL PASSAGE IS EXPECTED AT HAYS
AROUND 15Z AND THEN AT DODGE CITY AND GARDEN CITY AROUND 18Z.
GUSTY WINDS BEHIND THIS FRONT WILL GRADUALLY VEER MORE EASTERLY BY
00Z SUNDAY AND AFTER 03Z SUNDAY DECREASE INTO THE 10 TO 15 KNOT
RANGE. NAM BUFR SOUNDINGS DOES INDICATED SOME INCREASING MOISTURE
IN THE 2000 TO 3000FT AGL LEVEL BEHIND THIS FRONT AFTER 18Z IN
MAINLY THE HAYS AREA SO A PERIOD OF MVFR CEILINGS IS ANTICIPATED
LATER TODAY IN NORTH CENTRAL KANSAS. ELSEWHERE VFR CONDITIONS ARE
EXPECTED THROUGH THE EARLY EVENING.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 58 15 36 19 / 0 0 0 10
GCK 58 16 40 20 / 0 0 0 10
EHA 69 21 45 24 / 0 0 0 20
LBL 66 18 41 22 / 0 10 0 10
HYS 39 12 31 18 / 0 0 10 10
P28 59 16 31 18 / 0 10 10 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BURGERT
LONG TERM...RUTHI
AVIATION...BURGERT
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1121 PM CST FRI FEB 13 2015
...UPDATED SYNOPSIS AND AVIATION DISCUSSION...
.SYNOPSIS...
ISSUED AT 1119 PM CST FRI FEB 13 2015
AT 00Z SATURDAY AN UPPER LEVEL RIDGE AXIS EXTENDED FROM THE
WESTERN UNITED STATES INTO WESTERN ALBERTA. A +120KT 250MB JET
STREAK WAS LOCATED JUST WEST OF THIS UPPER LEVEL RIDGE AXIS AND
STRETCHED FROM EAST CENTRAL ALBERTA TO NORTHWEST NORTH DAKOTA. A
500MB TROUGH WAS LOCATED NEAR THE LEFT EXIT REGION OF THIS UPPER
LEVEL JET. AN AREA OF HIGHER MID LEVEL MOISTURE WAS PRESENT ACROSS
NORTH AND SOUTH DAKOTA AT 00Z SATURDAY WHICH WAS NEAR THE NOSE OF
THE 250MB JET AND JUST EAST OF A 700MB -2C TO -6C TEMPERATURE
GRADIENT. A 850MB COLD FRONT EXTENDED FROM WISCONSIN INTO EASTERN
NORTH DAKOTAS WITH -15C TO -20C TEMPERATURES OBSERVED NORTH OF
THIS FRONT OVER MINNESOTA AND NORTHERN WISCONSIN. THE SURFACE COLD
FRONT STRETCHED FROM SOUTHERN WISCONSIN TO NORTHEAST NEBRASKA TO
SOUTHEAST MONTANA.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 200 PM CST FRI FEB 13 2015
NORTHWEST FLOW ALOFT WILL CONTINUE OVER WESTERN KANSAS THROUGH THE
PERIOD. SOME RESIDUAL MID LEVEL MOISTURE, LIKELY BEING FORCED BY
SOME WEAK MID LEVEL WARM ADVECTION, WAS RESULTING IN AN AREA OF
CLOUDS OVER SOUTHWEST NEBRASKA AND NORTHWEST KANSAS THIS MORNING AND
EARLY AFTERNOON. SATELLITE TRENDS SHOW THIS AREA OF CLOUDS GRADUALLY
THINNING OUT WITH TIME SO WILL CONTINUE THE TREND FOR MOSTLY CLEAR
SKIES THROUGH THE EVENING AND OVERNIGHT HOURS. A WEAK SURFACE
PRESSURE PATTERN WILL ALSO CONTINUE TONIGHT ACROSS WESTERN KANSAS.
THE SURFACE WINDS ARE EXPECTED TO SETTLE INTO A WESTERLY DIRECTION
OVERNIGHT WHICH COULD HELP KEEP TEMPERATURES UP SOMEWHAT BUT GIVEN
THE CLEAR SKIES AND LOWER DEWPOINTS, WE SHOULD SEE TEMPERATURES
FALLING INTO THE LOWER TO MIDDLE 30S.
ON SATURDAY, A STRONG COLD FRONT WILL BACKDOOR INTO CENTRAL AND
SOUTHWEST KANSAS FROM THE NORTH/NORTHEAST, IN RESPONSE TO A CLOSED
UPPER LOW THAT WILL BE DROPPING RAPIDLY OUT OF CANADA AND THROUGH
THE GREAT LAKES REGION ON SATURDAY. THE NAM SEEMS TO BE A LITTLE
SLOWER WITH THIS FRONT COMPARED TO OTHER MODELS WHICH IS SOMEWHAT
CURIOUS AS IT SEEMS THESE FRONTS ARE USUALLY A LITTLE MORE
PROGRESSIVE THAN WHAT THE MODELS SHOW. AT ANY RATE, THERE WILL
LIKELY BE A NON DIURNAL TEMPERATURE PROFILE DURING THE DAY ACROSS
PROBABLY ALL BUT THE FAR SOUTHWEST COUNTIES AND THIS WILL BE
REFLECTED IN THE HOURLY TEMPERATURE FORECASTS. HAYS WILL BE THE
COOLEST DURING THE DAY AND MAY RISE A FEW DEGREES IN THE MORNING BUT
WILL SEE TEMPERATURES FALLING OFF THROUGH THE LATE MORNING AND
AFTERNOON. EXPECT HIGH TEMPERATURES THERE TO ONLY RISE INTO THE LOW
40S BEFORE FALLING BACK. FARTHER SOUTHWEST, HIGHS COULD REACH THE
MID AND UPPER 50S FROM GARDEN CITY AND DODGE CITY THROUGH MEDICINE
LODGE WITH UPPER 60S TO NEAR 70 DEGREES POSSIBLE AT ELKHART AND
HUGOTON. MODEL SOUNDINGS ALSO SUGGEST THAT LOW STRATUS WILL BE
DEVELOPING IN THE STRONG COLD ADVECTION ZONE BEHIND THE FRONT.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 223 PM CST FRI FEB 13 2015
RETROGRESSION OF THE UPPER LEVEL LONG WAVE PATTERN IS IN PROGRESS,
AND CONSIDERABLY COOLER WEATHER WILL RETURN TO THE CENTRAL PLAINS
AND PERSIST FOR THE REST OF FEBRUARY. WHEREAS THE FIRST PART OF THE
MONTH WAS CHARACTERIZED BY A RIDGE CENTERED 110-120W AND A PLUME OF
DOWNSLOPE-WARMED AIR IN THE PLAINS, THE REST OF THE MONTH IS LIKELY
TO BE CHARACTERIZED BY A LONG WAVE RIDGE CENTERED 120-130W AND ONLY
BRIEF PERIODS OF WARMING BETWEEN SURGES OF COLD AIR.
THE NUMERICAL MODELS ARE IN GOOD AGREEMENT ON EVOLUTION OF THE LARGE
SCALE FLOW, ALTHOUGH DIFFERENCES IN SYNOPTIC SCALE DETAILS BECOME
MORE EVIDENT BY LATE NEXT WEEK. THE ECMWF HAS TRENDED TOWARD THE
DRIER GFS SOLUTION FOR THE MINOR PRECIPITATION EVENT MONDAY AND
SEEMS REASONABLE. THE ECMWF IS SLOWER TO ERODE THE MODIFIED ARCTIC
AIR THAN THE GFS ON WEDNESDAY, AND THE GFS APPEARS TO GENERATE
EXCESSIVE LEE TROUGHING WITH STRONGLY MERIDIONAL FLOW. THE
DETERMINISTIC ECMWF SEEMS MORE REASONABLE BY THE MIDDLE OF NEXT
WEEK. THE ECMWF HAS MORE AMPLITUDE WITH THE UPPER LEVEL TROUGH THAT
REACHES THE WEST COAST THURSDAY THAN THE GFS AND BRINGS A MUCH
STRONGER TROUGH INTO THE SOUTHERN PLAINS FRIDAY NIGHT THAN DOES THE
GFS. MOST OF THE GFS ENSEMBLES MAINTAIN A SPLIT FLOW WITH A PORTION
OF THE TROUGH HANGING BACK IN THE SOUTHWESTERN UNITED STATES, AND
THE WEAKER GFS SOLUTION IS PREFERRED FOR NEXT WEEKEND.
THE COLD AIR MASS THAT WILL INVADE KANSAS SATURDAY AND SATURDAY
NIGHT WILL REMAIN ENTRENCHED IN THE CENTRAL PART OF THE COUNTRY
THROUGH WEDNESDAY. A MINOR UPPER LEVEL TROUGH NEAR 45N/145W THIS
AFTERNOON WILL PROGRESS THROUGH THE EASTERN PACIFIC RIDGE AND REACH
KANSAS ON SUNDAY. LOW LEVEL MOISTURE IN SOUTHWEST TEXAS WILL FLOW
NORTH OVER THE ARCTIC AIR AND SHOULD RESULT IN FORMATION OF
WIDESPREAD STRATUS SATURDAY NIGHT AND SUNDAY AS WINDS BECOME SOUTH
ABOVE THE ARCTIC AIR. MODEL SOUNDINGS SUGGEST THAT THE MOISTURE
LAYER WILL BE SHALLOW AND THAT HIGH DEWPOINT DEPRESSIONS WILL EXIST
BELOW THE MOIST LAYER. AS SUCH, THE POTENTIAL FOR FREEZING DRIZZLE
WITH THE LOW LEVEL ISENTROPIC LIFTING SEEMS MINIMAL IN WESTERN
KANSAS. THE STRATUS WILL BE SLOW TO DISSIPATE ON SUNDAY BUT LIKELY
WILL ERODE FROM WEST TO EAST AS LOW LEVEL WINDS BECOME MORE NORTH
FOLLOWING PASSAGE OF THE UPPER LEVEL TROUGH. THERE IS A CHANCE THAT
THERE COULD BE A FEW SNOW FLURRIES SUNDAY AFTERNOON WITH THE TROUGH,
BUT MODEL SOUNDINGS HAVE QUITE A BIT OF DRY AIR IN THE MID LEVELS TO
EVAPORATE MOST OF ANY PRECIPITATION THAT DEVELOPS.
TEMPERATURES SATURDAY NIGHT ARE SOMEWHAT PROBLEMATIC GIVEN THE COLD
AIR ADVECTION AND THE CLOUD COVER. THE REALLY COLD ARCTIC AIR WILL
REMAIN WELL EAST OF KANSAS, AND TEMPERATURES PROBABLY WILL NOT BE
ALL THAT FRIGID IN SOUTHWESTERN KANSAS. VALUES WERE ADJUSTED UP
SLIGHTLY. SUNDAY WILL BE COOL WITH CONSIDERABLE CLOUD COVER,
ESPECIALLY IN CENTRAL AND SOUTH CENTRAL KANSAS. THERE SHOULD BE
ENOUGH SUN TO ALLOW HIGHS IN THE LOW TO MID 40S IN FAR SOUTHWEST
KANSAS.
THE POTENTIAL FOR MEASURABLE PRECIPITATION WITH THE UPPER LEVEL
TROUGH THAT APPROACHES THE FOUR CORNERS AREA MONDAY EVENING IS NOT
THAT GREAT IN WESTERN KANSAS. UPWARD VERTICAL MOTION APPEARS TO BE
QUITE WEAK EAST OF THE COLORADO BORDER WITH WEAK MID LEVEL
FRONTOGENESIS AND MARGINAL DIFFERENTIAL POSITIVE VORTICITY ADVECTION
WITH THE DIGGING UPPER LEVEL TROUGH. SNOWFALL TOTALS WILL BE QUITE
LIGHT, AND ANYTHING MORE THAN AN INCH PROBABLY WILL BE RESTRICTED
TO MORTON COUNTY.
A STRONG JET STREAK IN THE NORTHWEST FLOW WILL MOVE INTO WESTERN
KANSAS TUESDAY, AND DIVERGENCE IN THE EXIT REGION OF THE JET STREAK
MAY PRODUCE ENOUGH VERTICAL MOTION FOR A FEW SNOW FLURRIES TUESDAY
AFTERNOON. SOME EROSION OF THE ARCTIC AIR WILL OCCUR IN FAR WESTERN
KANSAS WEDNESDAY, BUT THE GFS APPEARS TOO QUICK TO ERODE THE COLD
AIR. THE COLD AIR WILL SLOSH BACK WEST WEDNESDAY NIGHT AS YET
ANOTHER UPPER LEVEL TROUGH DROPS INTO THE UPPER MIDWEST. THE UPPER
LEVEL FLOW WILL BECOME LESS MERIDIONAL THURSDAY AND FRIDAY AS A
TROUGH MOVES THROUGH THE LONG WAVE RIDGE INTO THE WESTERN UNITED
STATES, AND DOWNSLOPE FLOW SHOULD SCOUR OUT THE REMNANTS OF THE
ARCTIC AIR THURSDAY AFTERNOON AND NIGHT. COOLER AIR WILL RETURN NEXT
WEEKEND, BUT THE DETAILS ARE UNCERTAIN. IF THE UPPER LEVEL TROUGH
COMES OUT IN ONE PIECE LIKE THE ECMWF ADVERTISES, THERE WILL BE A
CHANCE FOR LIGHT PRECIPITATION IN WESTERN KANSAS; HOWEVER, THE
WEAKER GFS SOLUTION SEEMS MORE REASONABLE.
ADDITIONAL SURGES OF COLD AIR ARE LIKELY EVERY FEW DAYS UNTIL A MORE
ZONAL FLOW REGIME RETURNS IN EARLY MARCH. THERE IS LITTLE INDICATION
THAT SIGNIFICANT PRECIPITATION IS LIKELY IN THE NEAR FUTURE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1119 PM CST FRI FEB 13 2015
NAM, RAP, AND HRRR WERE ALL IN DECENT AGREEMENT THIS MORNING WILL
MOVING A COLD FRONT ACROSS SOUTHWEST KANSAS BETWEEN 15Z AND 21Z
SATURDAY. AS THIS FRONT PASSES A SOUTHWEST/WESTERLY WIND AT 10
KNOTS OR LESS WILL SHIFT TO THE NORTHEAST AND THEN INCREASE TO
AROUND 20 KNOTS. AT THIS TIME FRONTAL PASSAGE IS EXPECTED AT HAYS
AROUND 15Z AND THEN AT DODGE CITY AND GARDEN CITY AROUND 18Z.
GUSTY WINDS BEHIND THIS FRONT WILL GRADUALLY VEER MORE EASTERLY BY
00Z SUNDAY AND AFTER 03Z SUNDAY DECREASE INTO THE 10 TO 15 KNOT
RANGE. NAM BUFR SOUNDINGS DOES INDICATED SOME INCREASING MOISTURE
IN THE 2000 TO 3000FT AGL LEVEL BEHIND THIS FRONT AFTER 18Z IN
MAINLY THE HAYS AREA SO A PERIOD OF MVFR CEILINGS IS ANTICIPATED
LATER TODAY IN NORTH CENTRAL KANSAS. ELSEWHERE VFR CONDITIONS ARE
EXPECTED THROUGH THE EARLY EVENING.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 37 58 15 36 / 0 0 0 0
GCK 32 59 17 40 / 0 0 0 0
EHA 37 69 24 45 / 0 0 0 0
LBL 35 65 20 41 / 0 0 10 0
HYS 33 37 12 31 / 0 0 0 10
P28 34 59 17 31 / 0 0 10 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BURGERT
SHORT TERM...GERARD
LONG TERM...RUTHI
AVIATION...BURGERT
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
409 AM EST SAT FEB 14 2015
.SYNOPSIS...
HIGH PRESSURE IS POSITIONED OFFSHORE. A STRONG COLD FRONT WILL CROSS
THE AREA THIS AFTERNOON AND EVENING...BRINGING AN ARCTIC BLAST
THROUGH EARLY WEEK. HIGH PRESSURE CROSSES THE AREA MONDAY. LOW
PRESSURE IS EXPTECTED TO TRACK NORTHEAST ACROSS THE DEEP SOUTH
MONDAY NIGHT...MOVING OFF THE NORTH CAROLINA COAST TUESDAY NIGHT
BEFORE TRACKING INTO THE GULF OF MAINE WEDNESDAY.
&&
.NEAR TERM /TODAY/...
AS OF 08Z...UPR LOW PRESSURE HEADED HERE THIS AFTERNOON/EVENING IS
CURRENTLY OVER NRN ONTARIO WITH 1001MB SFC LOW NORTH OF LAKE HURON.
THIS SYSTEM WILL SHIFT SE TO PHILLY BY THIS EVENING WITH A POWERFUL
COLD FRONT MOVING SE ACROSS THE CWA THIS AFTERNOON AND EVENING.
AHEAD OF THIS COLD FRONT...ISENTROPIC LIFT LOOKS TO CAUSE SNOW IN
THE NERN MD. CURRENT RETURNS OVER PA THE PRECURSOR. WITH 00Z NAM
CONTINUING 15-18Z LIGHT SNOW FOR GREATER BALTIMORE...DECIDED TO
RAISE A WINTER WEATHER ADVISORY THAT EXTENDS UNTIL MIDNIGHT TO
ACCOUNT FOR SNOW WITH THE COLD FRONT LATE THIS AFTERNOON AND
LINGERING SHOWERS THIS EVENING. PERHAPS HALF INCH THIS
MORNING...THEN AN ADDITIONAL 1-2IN FROM THE SQUALL/SHOWERS.
ELSEWHERE...SWLY FLOW THAT INCREASES TO 20 TO 25 MPH RAISES
TEMPERATURES BRIEFLY ABOVE FREEZING...PERHAPS 40F FOR KCHO.
HIGH RES GUIDANCE SUCH AS HRRR AND NAM NEST FEATURES SQUALL LIKE
SNOW SWATH WITH THE COLD FRONT. BURST OF SNOW AND WIND WILL COME ON
QUICKLY AND POTENTIALLY BE HAZARDOUS AS TEMPERATURES CRASH. ABOVE
FREEZING TEMPERATURES PRIOR TO THE SNOW WILL LIMIT THE IMMEDIATE
IMPACT AND IS WHY THE WINTER WEATHER ADVISORY IS NOT LARGER.
STATEMENT REGARDING THE SNOW AS IT COMES IN SEEMS SUFFICIENT TO
HIGHLIGHT THREATS OF UP TO 1 INCH OF SNOW AND SUBSEQUENT FREEZE UP.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY/...
COLDEST AIR OF THE SEASON FOLLOWS COLD FRONT WITH VERY WINDY
CONDITIONS. HIGH WIND WARNING AND WIND CHILL WARNING FOR MANY
AREA...ADVISORIES ELSEWHERE. TIMING OF WARNINGS WERE BASED ON
ADVISORY CRITERIA. PLEASE SEE NPWLWX AND WSWLWX FOR SPECIFICS WITH
THOSE. HEADLINE DECISIONS BASED ON GFS BASED MOSGUIDE WINDS AND
TEMPERATURES FROM MET/SREF BLEND. CRITERIA FOR WIND CHILL IS -25F
FOR NRN MD AND WEST FROM BLUE RIDGE...-20F EAST. HIGH WIND CRITERIA
IS 58 MPH (50 KNOTS). WIND CHILL HEADLINES GO UNTIL NOON WHEN AN
ADVISORY EXTENSION IS LIKELY INTO SUNDAY NIGHT FOR MUCH OF THE AREA.
WIND HEADLINES DROP NOON OR 2PM SUNDAY...SHOULD COVER THE TIMEFRAME
OF WIND ADVISORY GUSTS.
OTHERWISE SATURDAY EVENING...SNOW TAPERS TO ISOLATED SHOWERS BEHIND
THE COLD FRONT FROM WEST TO EAST. CURRENT THOUGHT IS PRECIP END TIME
OF AROUND 7PM FOR INTERSTATE 95...9PM OR SO FOR THE WRN SHORE OF THE
BAY/SRN MD.
UPSLOPE SNOW BEGINS THIS MORNING AND IS HEAVIEST THIS AFTERNOON...
ADVISORY OUT THERE 10AM TO MIDNIGHT WITH TOTAL ACCUM 3-5 INCHES.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
SUNDAY NGT WL BE ESPECIALLY COLD AND DRY. I DON`T NRMLY ADDRESS
DWPTS IN THE DSCN....BUT WE ARE LOOKING AT DWPTS OF BTWN -5 AND
-15. I DID A QUICK CHECK OF LAST JAN/FEB DWPTS: AS WE ALL KNOW
LAST JAN/FEB HAD A LOT OF COLD AIR. IN 2014 DC AREA HAD LOWEST
DWPT READING OF -14 IN JAN...AND -11 IN FEB...BUT VALUES THIS LOW
HERE ARE FAIRLY RARE. STATIC ELECTRICITY WL BE HIGH.
AFTR THE XTRMLY STRONG WIND OF SUN THESE WL BE SLOW TO DIMINISH
SUN NGT. THIS WL LKLY LEAD TO MORE WIND CHILL ADVSORIES BEING
NEEDED. THERE IS A PTNL FOR RECORD LOW TEMPS TO BE REACHED - SEE
CLIMATE SXN BLO FOR NUMBERS.
HIGH PRES OVR THE AREA MON. HIGHS SHOULD CLIMB BACK INTO L20S W/
LGTR WINDS.
THE EURO HAS BEEN PERFORMING WELL AS OF LATE - IT HAD TMRW`S STRONG
NEW ENGLAND CSTL LOW PEGGED LAST MON. THERE IS CONCERN ABT THE
FATE OF AN AREA OF LOW PRES COMING FM THE GULF STATES MON NGT. THE
GFS HAS IT OVR GA TUE AFTN...TURNING NE NEAR ORF AND INTENSIFYING
TUE NGT AS IT TRACKS OVR CAPE COD. THE EURO KEEPS IT FURTHER S -
NEAR HAT AT 06Z WED...THEN TAKING A MORE EWD TRACK AND IMPACTING
ATLC CANADA. THE GFS SOLN WOULD BE MORE PROBLEMATIC FOR MID ALTC.
WE ARE CURRENTLY FCSTG A CHC OF SN TUE/TUE NGT...LKLY SE OF DC.
DEPENDING UPON EVENTUAL TRACK THESE MAY BE CHGD.
TEMPS RMNG WELL BLO NRML THRU THE END OF THE WK. HIGHS SHOULD BE
IN THE M40S/LOWS M20S IN MID FEB.
&&
.AVIATION /09Z SATURDAY THROUGH WEDNESDAY/...
HIGH PRESSURE OFFSHORE WITH RETURN FLOW TODAY...MOISTENING LATE THIS
MORNING WITH BRIEF SNOW/MVFR FOR BALTIMORE AREA ROUGHLY 15-18Z. VERY
STRONG COLD FRONT CROSSES THE TERMINALS EARLY SATURDAY EVENING WITH
SNOW SQUALLS IN THE AFTERNOON/EARLY EVENING FOR DC METROS. NORTHWEST
WINDS OF 30 KT AND GUSTS 45 TO 50 KT. SNOW THREAT ENDS DURING THE
EVENING FOR THE TERMINALS...LINGERING LONGEST FOR BALTIMORE. WINDS
STRENGTHEN OVERNIGHT...AND ONLY SLOW DIMINISH SUNDAY...PERHAPS 35 TO
40 KT GUSTS FOR THE AFTERNOON SUNDAY.
GUSTY WINDS CONT SUN NGT. HIGH PRES OVR THE AREA MON. CLDS MAY
INCRS MON NGT/TUE AS LOW PRES DVLPS OVR THE GULF STATES. DEPENDING
UPON THE STORM TRACK WL DETERMINE IF MID ATLC WL SEE LOWER
CLDS/SNOW TUE AND TUE NGT OR JUST HIGHER CLDS.
&&
.MARINE...
HIGH PRESSURE DRIFTS EAST FROM THE COAST THIS MORNING WITH RETURN
FLOW CHANNELING 20 KT UP THE BAY. SCA NOW FOR SRN MD WATERS...
EXPANDING TO ALL WATERS THIS MORNING AS WIND BECOMES SWLY AND
INCREASES AHEAD OF A VERY STRONG COLD FRONT THAT CROSSES THE WATERS
EARLY THIS EVENING. BRIEF SNOW...BUT MAIN STORY IS 40 TO 50 KT WIND
GUSTS THIS EVENING THROUGH SUNDAY MORNING AND 35 TO 40 KT GUSTS
SUNDAY AFTERNOON. STORM WARNING BEGINS AT 6PM SHARP AND CONTINUES
THROUGH SUNDAY. LIKELY DROPPED FOR A GALE WARNING SUNDAY AFTERNOON
WHICH MAY LINGER INTO THE EVENING...SCA THEN INTO MONDAY.
WINDS MAY BE GALE SUN NGT...OR HIGH END SCA. THESE WL DIMINISH
DURG THE DAY MON...BUT HV THE PTNL TO INCRS AGN TUE THRU WED
DEPENDING ON THE TRACK OF A GULF STATE CSTL LOW. SCA`S MAY BE
NEEDED TUE-WED.
&&
.FIRE WEATHER...
HIGH PRESSURE BUILDING INTO THE REGION SUNDAY WILL BRING AN ENHANCED
FIRE THREAT. NW WINDS WILL GUST BETWEEN 45 AND 55 MPH SUNDAY
MORNING...ONLY DECREASING TO 30 AND 40 MPH SUNDAY AFTN/EVENING.
THE HIGH WILL BRING A VERY COLD AND DRY AIRMASS...RESULTING IN RH
VALUES DROPPING INTO THE 20S ACROSS CENTRAL VA...30S IN
EASTERN/CENTRAL MD...AND 50S WEST OF THE BLUE RIDGE. THE LAST
COMPONENT OF CONCERN IS THE 10 HR FUEL MOISTURE...WHICH CURRENTLY
ARE FORECASTED TO BE JUST BELOW 10 PERCENT. WE`LL MONITOR THE
TREND AND COLLABORATE WITH STATE FIRE SUPERVISORS TO DETERMINE THE
NEED OF A STATEMENT OR WARNING FOR SUNDAY.
&&
.CLIMATE...
VERY COLD AIR WILL MOVE INTO THE REGION SATURDAY NIGHT. HERE ARE
RECORD LOW TEMPERATURES FOR SUNDAY AND MONDAY FOR OUR THREE MAIN
CLIMATE SITES:
RECORD LOW MIN...FEB 15:
BWI...6 (1899/1943)
DCA...-6 (1899)
IAD...7 (1965)
RECORD LOW MAX...FEB 15:
BWI...18 (1943)
DCA...18 (1943)
IAD...22 (1979)
RECORD LOW MIN...FEB 16:
BWI...5 (1905)
DCA...5 (1905)
IAD...11 (1963/1987)
RECORD LOW MAX...FEB 16:
BWI...18 (1904)
DCA...18 (1904)
IAD...22 (2003)
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...HIGH WIND WARNING FROM 6 PM THIS EVENING TO 2 PM EST SUNDAY
FOR DCZ001.
WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO NOON EST SUNDAY
FOR DCZ001.
MD...WINTER WEATHER ADVISORY FROM 10 AM THIS MORNING TO MIDNIGHT
EST TONIGHT FOR MDZ006-011-014-501-506>508.
WIND CHILL WARNING FROM 7 PM THIS EVENING TO 6 PM EST SUNDAY
FOR MDZ501.
WIND CHILL WARNING FROM MIDNIGHT TONIGHT TO NOON EST SUNDAY
FOR MDZ003>006-502-503-505-507.
HIGH WIND WARNING FROM 6 PM THIS EVENING TO 2 PM EST SUNDAY
FOR MDZ003>006-011-013-014-016>018-503>508.
WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO NOON EST SUNDAY
FOR MDZ011-013-014-016>018-504-506-508.
WIND ADVISORY FROM 4 PM THIS AFTERNOON TO NOON EST SUNDAY FOR
MDZ501-502.
VA...HIGH WIND WARNING FROM 4 PM THIS AFTERNOON TO NOON EST SUNDAY
FOR VAZ025>027-029-503-504-507-508.
WINTER WEATHER ADVISORY FROM 10 AM THIS MORNING TO MIDNIGHT
EST TONIGHT FOR VAZ503.
WIND CHILL WARNING FROM 7 PM THIS EVENING TO 6 PM EST SUNDAY
FOR VAZ503.
WIND CHILL WARNING FROM MIDNIGHT TONIGHT TO NOON EST SUNDAY
FOR VAZ028-031-504-505-507-508.
HIGH WIND WARNING FROM 6 PM THIS EVENING TO 2 PM EST SUNDAY
FOR VAZ028-030-031-040-051>055-057-501-502-505-506.
WIND ADVISORY FROM 6 PM THIS EVENING TO 2 PM EST SUNDAY FOR
VAZ036>039-050-056.
WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO NOON EST SUNDAY
FOR VAZ025>027-029-030-036>040-050>057-501-502-506.
WV...HIGH WIND WARNING FROM 4 PM THIS AFTERNOON TO NOON EST SUNDAY
FOR WVZ055-505-506.
WINTER WEATHER ADVISORY FROM 10 AM THIS MORNING TO MIDNIGHT
EST TONIGHT FOR WVZ501-503-505.
WIND CHILL WARNING FROM 7 PM THIS EVENING TO 6 PM EST SUNDAY
FOR WVZ501-503-505.
WIND CHILL WARNING FROM MIDNIGHT TONIGHT TO NOON EST SUNDAY
FOR WVZ050>053-055-502-504-506.
HIGH WIND WARNING FROM 6 PM THIS EVENING TO 2 PM EST SUNDAY
FOR WVZ051>053.
WIND ADVISORY FROM 4 PM THIS AFTERNOON TO NOON EST SUNDAY FOR
WVZ050-501>504.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS EVENING FOR
ANZ532>534-537-540>543.
STORM WARNING FROM 6 PM THIS EVENING TO 6 PM EST SUNDAY FOR
ANZ530>543.
SMALL CRAFT ADVISORY FROM 10 AM THIS MORNING TO 6 PM EST THIS
EVENING FOR ANZ530-531-535-536-538-539.
&&
$$
PRODUCTS...BAJ/WOODY!
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
359 AM EST SAT FEB 14 2015
.SYNOPSIS...
HIGH PRESSURE IS POSITIONED OFFSHORE. A STRONG COLD FRONT WILL CROSS
THE AREA THIS AFTERNOON AND EVENING...BRINGING AN ARCTIC BLAST
THROUGH EARLY WEEK. HIGH PRESSURE CROSSES THE AREA MONDAY. LOW
PRESSURE IS EXPTECTED TO TRACK NORTHEAST ACROSS THE DEEP SOUTH
MONDAY NIGHT...MOVING OFF THE NORTH CAROLINA COAST TUESDAY NIGHT
BEFORE TRACKING INTO THE GULF OF MAINE WEDNESDAY.
&&
.NEAR TERM /TODAY/...
AS OF 08Z...UPR LOW PRESSURE HEADED HERE THIS AFTERNOON/EVENING IS
CURRENTLY OVER NRN ONTARIO WITH 1001MB SFC LOW NORTH OF LAKE HURON.
THIS SYSTEM WILL SHIFT SE TO PHILLY BY THIS EVENING WITH A POWERFUL
COLD FRONT MOVING SE ACROSS THE CWA THIS AFTERNOON AND EVENING.
AHEAD OF THIS COLD FRONT...ISENTROPIC LIFT LOOKS TO CAUSE SNOW IN
THE NERN MD. CURRENT RETURNS OVER PA THE PRECURSOR. WITH 00Z NAM
CONTINUING 15-18Z LIGHT SNOW FOR GREATER BALTIMORE...DECIDED TO
RAISE A WINTER WEATHER ADVISORY THAT EXTENDS UNTIL MIDNIGHT TO
ACCOUNT FOR SNOW WITH THE COLD FRONT LATE THIS AFTERNOON AND
LINGERING SHOWERS THIS EVENING. PERHAPS HALF INCH THIS
MORNING...THEN AN ADDITIONAL 1-2IN FROM THE SQUALL/SHOWERS.
ELSEWHERE...SWLY FLOW THAT INCREASES TO 20 TO 25 MPH RAISES
TEMPERATURES BRIEFLY ABOVE FREEZING...PERHAPS 40F FOR KCHO.
HIGH RES GUIDANCE SUCH AS HRRR AND NAM NEST FEATURES SQUALL LIKE
SNOW SWATH WITH THE COLD FRONT. BURST OF SNOW AND WIND WILL COME ON
QUICKLY AND POTENTIALLY BE HAZARDOUS AS TEMPERATURES CRASH. ABOVE
FREEZING TEMPERATURES PRIOR TO THE SNOW WILL LIMIT THE IMMEDIATE
IMPACT AND IS WHY THE WINTER WEATHER ADVISORY IS NOT LARGER.
STATEMENT REGARDING THE SNOW AS IT COMES IN SEEMS SUFFICIENT TO
HIGHLIGHT THREATS OF UP TO 1 INCH OF SNOW AND SUBSEQUENT FREEZE UP.
COLDEST AIR OF THE SEASON FOLLOWS COLD FRONT WITH VERY WINDY
CONDITIONS. HIGH WIND WARNING AND WIND CHILL WARNING FOR MANY
AREA...ADVISORIES ELSEWHERE. TIMING OF WARNINGS WERE BASED ON
ADVISORY CRITERIA. PLEASE SEE NPWLWX AND WSWLWX FOR SPECIFICS WITH
THOSE. HEADLINE DECISIONS BASED ON GFS BASED MOSGUIDE WINDS AND
TEMPERATURES FROM MET/SREF BLEND. CRITERIA FOR WIND CHILL IS -25F
FOR NRN MD AND WEST FROM BLUE RIDGE...-20F EAST. HIGH WIND CRITERIA
IS 58 MPH (50 KNOTS). WIND CHILL HEADLINES GO UNTIL NOON WHEN AN
ADVISORY EXTENSION IS LIKELY INTO SUNDAY NIGHT FOR MUCH OF THE AREA.
WIND HEADLINES DROP NOON OR 2PM SUNDAY...SHOULD COVER THE TIMEFRAME
OF WIND ADVISORY GUSTS.
OTHERWISE SATURDAY EVENING...SNOW TAPERS TO ISOLATED SHOWERS BEHIND
THE COLD FRONT FROM WEST TO EAST. CURRENT THOUGHT IS PRECIP END TIME
OF AROUND 7PM FOR INTERSTATE 95...9PM OR SO FOR THE WRN SHORE OF THE
BAY/SRN MD.
UPSLOPE SNOW BEGINS THIS MORNING AND IS HEAVIEST THIS AFTERNOON...
ADVISORY OUT THERE 10AM TO MIDNIGHT WITH TOTAL ACCUM 3-5 INCHES.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
SUNDAY NGT WL BE ESPECIALLY COLD AND DRY. I DON`T NRMLY ADDRESS
DWPTS IN THE DSCN....BUT WE ARE LOOKING AT DWPTS OF BTWN -5 AND
-15. I DID A QUICK CHECK OF LAST JAN/FEB DWPTS: AS WE ALL KNOW
LAST JAN/FEB HAD A LOT OF COLD AIR. IN 2014 DC AREA HAD LOWEST
DWPT READING OF -14 IN JAN...AND -11 IN FEB...BUT VALUES THIS LOW
HERE ARE FAIRLY RARE. STATIC ELECTRICITY WL BE HIGH.
AFTR THE XTRMLY STRONG WIND OF SUN THESE WL BE SLOW TO DIMINISH
SUN NGT. THIS WL LKLY LEAD TO MORE WIND CHILL ADVSORIES BEING
NEEDED. THERE IS A PTNL FOR RECORD LOW TEMPS TO BE REACHED - SEE
CLIMATE SXN BLO FOR NUMBERS.
HIGH PRES OVR THE AREA MON. HIGHS SHOULD CLIMB BACK INTO L20S W/
LGTR WINDS.
THE EURO HAS BEEN PERFORMING WELL AS OF LATE - IT HAD TMRW`S STRONG
NEW ENGLAND CSTL LOW PEGGED LAST MON. THERE IS CONCERN ABT THE
FATE OF AN AREA OF LOW PRES COMING FM THE GULF STATES MON NGT. THE
GFS HAS IT OVR GA TUE AFTN...TURNING NE NEAR ORF AND INTENSIFYING
TUE NGT AS IT TRACKS OVR CAPE COD. THE EURO KEEPS IT FURTHER S -
NEAR HAT AT 06Z WED...THEN TAKING A MORE EWD TRACK AND IMPACTING
ATLC CANADA. THE GFS SOLN WOULD BE MORE PROBLEMATIC FOR MID ALTC.
WE ARE CURRENTLY FCSTG A CHC OF SN TUE/TUE NGT...LKLY SE OF DC.
DEPENDING UPON EVENTUAL TRACK THESE MAY BE CHGD.
TEMPS RMNG WELL BLO NRML THRU THE END OF THE WK. HIGHS SHOULD BE
IN THE M40S/LOWS M20S IN MID FEB.
&&
.AVIATION /07Z SATURDAY THROUGH WEDNESDAY/...
GUSTY WINDS CONT SUN NGT. HIGH PRES OVR THE AREA MON. CLDS MAY
INCRS MON NGT/TUE AS LOW PRES DVLPS OVR THE GULF STATES. DEPENDING
UPON THE STORM TRACK WL DETERMINE IF MID ATLC WL SEE LOWER
CLDS/SNOW TUE AND TUE NGT OR JUST HIGHER CLDS.
&&
.MARINE...
WINDS MAY BE GALE SUN NGT...OR HIGH END SCA. THESE WL DIMINISH
DURG THE DAY MON...BUT HV THE PTNL TO INCRS AGN TUE THRU WED
DEPENDING ON THE TRACK OF A GULF STATE CSTL LOW. SCA`S MAY BE
NEEDED TUE-WED.
&&
.FIRE WEATHER...
HIGH PRESSURE BUILDING INTO THE REGION SUNDAY WILL BRING AN ENHANCED
FIRE THREAT. NW WINDS WILL GUST BETWEEN 45 AND 55 MPH SUNDAY
MORNING...ONLY DECREASING TO 30 AND 40 MPH SUNDAY AFTN/EVENING.
THE HIGH WILL BRING A VERY COLD AND DRY AIRMASS...RESULTING IN RH
VALUES DROPPING INTO THE 20S ACROSS CENTRAL VA...30S IN
EASTERN/CENTRAL MD...AND 50S WEST OF THE BLUE RIDGE. THE LAST
COMPONENT OF CONCERN IS THE 10 HR FUEL MOISTURE...WHICH CURRENTLY
ARE FORECASTED TO BE JUST BELOW 10 PERCENT. WE`LL MONITOR THE
TREND AND COLLABORATE WITH STATE FIRE SUPERVISORS TO DETERMINE THE
NEED OF A STATEMENT OR WARNING FOR SUNDAY.
&&
.CLIMATE...
VERY COLD AIR WILL MOVE INTO THE REGION SATURDAY NIGHT. HERE ARE
RECORD LOW TEMPERATURES FOR SUNDAY AND MONDAY FOR OUR THREE MAIN
CLIMATE SITES:
RECORD LOW MIN...FEB 15:
BWI...6 (1899/1943)
DCA...-6 (1899)
IAD...7 (1965)
RECORD LOW MAX...FEB 15:
BWI...18 (1943)
DCA...18 (1943)
IAD...22 (1979)
RECORD LOW MIN...FEB 16:
BWI...5 (1905)
DCA...5 (1905)
IAD...11 (1963/1987)
RECORD LOW MAX...FEB 16:
BWI...18 (1904)
DCA...18 (1904)
IAD...22 (2003)
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...HIGH WIND WATCH FROM THIS EVENING THROUGH SUNDAY MORNING FOR
DCZ001.
MD...WINTER WEATHER ADVISORY FROM NOON TODAY TO MIDNIGHT EST
TONIGHT FOR MDZ501.
HIGH WIND WATCH FROM THIS EVENING THROUGH SUNDAY MORNING FOR
MDZ003>006-011-013-014-016>018-501>508.
WIND CHILL WATCH FROM LATE TONIGHT THROUGH SUNDAY MORNING FOR
MDZ003>006-501>503-505-507.
VA...WINTER WEATHER ADVISORY FROM NOON TODAY TO MIDNIGHT EST
TONIGHT FOR VAZ503.
HIGH WIND WATCH FROM THIS EVENING THROUGH SUNDAY MORNING FOR
VAZ025>031-036>040-050>057-501>508.
WIND CHILL WATCH FROM LATE TONIGHT THROUGH SUNDAY MORNING FOR
VAZ025>031-503>505-507-508.
WV...WINTER WEATHER ADVISORY FROM NOON TODAY TO MIDNIGHT EST
TONIGHT FOR WVZ501-503-505.
HIGH WIND WATCH FROM THIS EVENING THROUGH SUNDAY MORNING FOR
WVZ050>053-055-501>506.
WIND CHILL WATCH FROM LATE TONIGHT THROUGH SUNDAY MORNING FOR
WVZ050>053-055-501>506.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS EVENING FOR
ANZ532>534-537-540>543.
STORM WARNING FROM 6 PM THIS EVENING TO 6 AM EST SUNDAY FOR
ANZ530>543.
SMALL CRAFT ADVISORY FROM 10 AM THIS MORNING TO 6 PM EST THIS
EVENING FOR ANZ530-531-535-536-538-539.
&&
$$
PRODUCTS...BAJ/WOODY!
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
330 PM EST SAT FEB 14 2015
LATEST UPDATE...
SYNOPSIS/SHORT TERM/LONG TERM
.SYNOPSIS...
ISSUED AT 330 PM EST SAT FEB 14 2015
DANGEROUS COLD IS IN STORE TONIGHT AND SUNDAY MORNING. WIND CHILLS
OF 20 TO 35 BELOW WILL RESULT IN FROSTBITE TIMES OF 15 MINUTES OR
LESS.
STRONG WINDS AND BLOWING SNOW WILL SUBSIDE THIS EVENING. HEAVY SNOW
SHOWERS NEAR LAKE MICHIGAN WILL END BY MIDNIGHT. WIND CHILLS WILL
RECOVER SUNDAY AFTERNOON WITH LIGHT WINDS AND BRIGHT SUNSHINE BUT
HIGH TEMPERATURES WILL BE ONLY IN THE SINGLE DIGITS.
TEMPERATURES WILL CONTINUE TO AVERAGE WELL BELOW FOR THE NEXT WEEK
OR MORE. ADDITIONAL PERIODS OF SNOW ARE LIKELY... HEAVY AT TIMES
NEAR LAKE MICHIGAN.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 330 PM EST SAT FEB 14 2015
ATTENTION SHIFTS FROM SNOW/BLOWING SNOW AND HIGH WINDS TO EXTREME
COLD TONIGHT. THE ONGOING HEADLINES WILL REMAIN IN EFFECT FOR A FEW
MORE HOURS TO COVER THE PERIODIC WHITEOUT/GROUND BLIZZARD SITUATION
THEN BECOME WIND CHILL HEADLINES.
WIND GUSTS ARE PEAKING NOW THROUGH ABOUT 5 PM BUT ARE EXPECTED TO
SHUT DOWN PRETTY QUICK THIS EVENING AS THE BOUNDARY LAYER DECOUPLES
SHORTLY AFTER 7 PM. HOWEVER SUSTAINED WINDS DO STAY UP MUCH OF THE
NIGHT WITH SPEEDS OF 10 TO 20 MPH. GUIDANCE HAS BEEN CONSISTENT
SHOWING AIR TEMPS FALLING TO 5 TO 15 BELOW WHICH SUPPORTS MIN WIND
CHILLS REACHING 25 BELOW OR LOWER OVER MUCH OF THE AREA.
INLAND CLEARING/LAND BREEZE FORMATION THIS EVENING WILL ASSIST IN
SENDING LAKESHORE SNOWS OFFSHORE. LATEST HRRR HAS THE LAKE EFFECT
SNOW BANDS SHIFTING OFFSHORE OF MKG AROUND 7 PM...HOLLAND AROUND 8
PM... SOUTH HAVEN AROUND 10 PM... AND LUDINGTON AROUND MIDNIGHT.
SURFACE RIDGING BUILDS IN QUICKLY ON SUNDAY CAUSING WINDS TO LIGHTEN
UP CONSIDERABLY. THUS WIND CHILLS RECOVER SUBSTANTIALLY IN THE
AFTERNOON UNDER BRIGHT SKIES IN FRIGID ARCTIC AIR MASS.
HI RES MODELS BEYOND 24 HOURS INDICATE MESOLOW CIRCULATION WILL
DEVELOP OVER SRN OR CNTRL LAKE MICHIGAN WITHIN MID LAKE CONVERGENCE
BAND. THIS SEEMS REASONABLE GIVEN VERY COLD/CLEAR SYNOPTIC PATTERN
AND STRONG LAND BREEZE CIRCULATIONS ON ALL SIDES OF LK MI. THIS
FEATURE SHOULD EVENTUALLY COME ONSHORE NORTH OF HOLLAND LATE SUNDAY
NIGHT OR MONDAY MORNING AS SYNOPTIC FLOW TURNS SOUTHWESTERLY.
MID LAKE MESO FEATURES CAN PRODUCE EXCESSIVE SNOW RATES... SO THIS
WILL NEED TO BE CLOSELY WATCHED. ALSO DEEPER MOISTURE ARRIVES ABOUT
THE SAME THIS FEATURE COMES ONSHORE AND THE DGZ RETURNS BACK INTO
THE CLOUD LAYER DUE TO WARMING. ADVISORY/WARNING MAY BE NEEDED
MON/MON NGT FOR WEST CENTRAL LWR MI INCLUDING MKG/LDM AREAS.
POSSIBLY BIV/GRR AS WELL DEPENDING ON MEAN LOW LEVEL WIND DIRECTION.
.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 330 PM EST SAT FEB 14 2015
THE LONG RANGE FORECAST PERIOD CONTINUES TO LOOK VERY COLD AND
SNOWY. ANOTHER SURGE OF ARCTIC AIR WILL BEGIN TO ARRIVE LATE TUESDAY
THROUGH TUESDAY NIGHT BEHIND THE ARCTIC COLD FRONT. MAX TEMPS
WEDNESDAY THROUGH FRIDAY WILL STRUGGLE TO REACH THE UPPER SINGLE
DIGITS TO LOWER TEENS.
THE ARCTIC FRONT WILL BRING POTENTIAL FOR A ROUND OF SNOW SHOWERS
TUESDAY WITH LAKE EFFECT SNOW SHOWERS ANTICIPATED MID TO LATE WEEK.
SIGNIFICANT HEAVY LAKE EFFECT SNOW EVENTS ARE NOT ANTICIPATED BUT
SEVERAL INCHES OF VERY DRY FLUFFY SNOW ARE POSSIBLE THROUGH MID TO
LATE WEEK.
WIND CHILL VALUES WILL BE QUITE COLD AS WELL MID TO LATE WEEK. WIND
CHILL READINGS WEDNESDAY THROUGH FRIDAY MORNING COULD BE COLDER THAN
15 DEGREES BELOW ZERO... ESPECIALLY OVER THE INTERIOR.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY)
ISSUED AT 1210 PM EST SAT FEB 14 2015
IFR/MVFR CONDITIONS WILL CONTINUE THIS AFTERNOON DUE TO SNOW SHOWERS
AND BLOWING SNOW WITH VERY WINDY CONDITIONS. NNW WINDS WILL CONTINUE
TO GUST TO 30 TO 40 KTS THROUGH THE AFTERNOON AND EARLY EVENING
BEFORE SUBSIDING VERY QUICKLY MID TO LATE EVENING.
CONDITIONS WILL IMPROVE TO VFR THIS EVENING AND OVERNIGHT AS SKIES
CLEAR. THE ONLY EXCEPTION TO THIS IS AT KMKG WHERE SOME LOW CLOUDS
WILL LIKELY STILL LINGER THIS EVENING RESULTING IN MVFR CONDITIONS
THERE. VFR CONDITIONS WITH LIGHT NE WINDS ARE ANTICIPATED AT ALL THE
TERMINALS SUNDAY.
&&
.HYDROLOGY...
ISSUED AT 1115 AM EST SAT FEB 14 2015
THE CORE OF THE WINTER SEASONS COLDEST AIR WILL CONTINUE TO MOVE IN
THROUGH THE DAY TODAY INTO SUNDAY. TEMPERATURES WILL CONTINUE TO
TUMBLE.
THEREFORE...ICE HAS NOT BUDGED AND CONDITIONS ARE STABLE. THERE IS
IS LOW RISK THAT ANY MOVEMENT WILL OCCUR THROUGH NEXT WEEK AS THE
WARMEST HIGH TEMPERATURES IN THE NEXT SEVERAL DAYS ONLY REACH INTO
THE 20S. DAILY AVERAGE TEMPERATURES IN THE SINGLE DIGITS AND TEENS
WILL AID IN ADDITIONAL ICE FORMATION OR EXPANSION.
LIQUID CONTRIBUTION WILL REMAIN RATHER LOW DAY TO DAY. ADDITIONAL
ROUNDS OF SNOW ARE POSSIBLE THIS WEEK...ESPECIALLY ALONG THE LAKE
SHORE...BUT NOT MUCH MELTING WILL BE TAKING PLACE THROUGH THE PERIOD.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER STORM WARNING UNTIL 10 PM EST THIS EVENING FOR
MIZ037-038-
043-044-050-056-057-064-071.
WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR MIZ039-
040-045-046-051-052-058-059-065>067-072>074.
LM...NONE.
&&
$$
SYNOPSIS...MEADE
SHORT TERM...MEADE
LONG TERM...LAURENS
AVIATION...LAURENS
HYDROLOGY...JAM
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
605 PM CST Sun Feb 15 2015
.SHORT TERM: (Tonight through Monday Night)
Issued at 255 PM CST Sun Feb 15 2015
All data continues to show a winter storm impacting the area tonight
into Sunday, and the 12z model guidance generally is close to the
previous 00z/06z runs adding to the event confidence. That said
there is still significant uncertainty on aspects of the forecast,
namely where the frontogenetical band will set-up and the snow it
will produce before 06z, and the northern edge of snow thereafter.
The overall scenario has changed little since the previous forecast.
Radar currently shows that the initial snow band is trying to
develop from near KSTJ-KMBY-KSET-KSLO in response to strong mid
level frontogenetical forcing and weak warm advection. I have not
seen any snow reports thus far so we are still in the saturation
process due to dry antecedant low levels. Fronotogenetical forcing
and low level warm advection will ramp-up through the remainder of
this afternoon and especially this evening and the expectation is
that this evolving band will intensify producing moderate snowfall
between the 00-06z period. A blend of available short-term
guidance from the RAP, HRRR and deterministic guidance suggests
the band will become established just north of I-70 and become
more west-east oriented producing ~3 inches by 06z.
After 06z conditions begin to change due to the short-wave digging
southeastward into the central Plains. The response appears to be a
southward shift in the mid level frontogenesis and warm advection
supporting this northern band, and increasing large scale ascent
with a vort max head of trof and the backbuilding ULJ. Thus after
06z the primary forcing and ascent shifts southward along and south
of I-70. This would suggest that the northern snow band will fade
while a new and much larger swath of snow spreads/develops across
the southern half of MO/IL. This will place the I-70 corridor on the
northern part of the snow shield and could play havoc with amounts
along the I-70 corridor where the greatest uncertainty in the
forecast resides. Large scale ascent with the migrating short wave
trof and mid level frontogenesis will keep the heart of the snow band
focused south of I-70 across southern MO and southern IL on Sunday
morning with Columbia-St. Louis-Vandalia IL still on the northern
periphery of the deformation snow shield. By mid-late afternoon the
forcing will exit to the east of the area in association with the
migrating short wave trof, bringing and end to the snowfall.
Despite the very cold temperatures and dry nature of the snow, the
sounding profiles continue to show a shallow dendritic growth zone
with much larger profiles supporting columns and plates within the
lift zone. This suggests snow ratios closer to 13-15:1.
The new forecast is not far from the previous one but is a bit lower
in snow totals along I-70 with 5-7 inches due to the uncertainties
discussed, but still looking at 8+ southeast MO into southern IL.
This forecast will need to be further refined this evening in
anticipation of the northern frontogenetic snow band.
No changes needed to the previously issued winter storm watch and
advisories.
Glass
.LONG TERM: (Tuesday through Next Sunday)
Issued at 255 PM CST Sun Feb 15 2015
A cold front wil move southeastward through our forecast area on
Tuesday as a broad positively tilted upper level trough gradually
deepens over the region. There may be some post fronal light snow
Tuesday and Tuesday night, mainly across central and southeast MO
and southwest IL. A secondary cold front will drop southeastward
through our area late Tuesday night and Wednesday morning. Very
cold air is expected to invade our forecast area behind this second
front as a strong surface ridge bulds southeastward into MO from the
northern Plains. The models drop the -24 degree C 850 mb isotherm
southward to near STL on Wednesday. Temperatures on Wednesday and
Wednesday night should be close to 30 degrees below normal due to
this very cold air mass along with snow cover across most of the
forecast area from the recent winter storm. A warming trend should
begin Thursday night due to rising upper level heights along with
surface winds becoming southerly as the surface ridge shifts east of
our area. There may be some light snow Thursday night and Friday,
mainly across southeast MO and southwest IL, due to low-mid level
warm air advection. There will be a better chance of more
significant precipitation Friday night through Sunday as a cold
front sags southward into the area and a southern stream shortwave
approaches. Precipitation type will be in question along and ahead
of the cold front, but should be all snow by Saturday night or
Sunday as another cold air mass drops southward through our area
behind the front.
GKS
&&
.AVIATION: (For the 00z TAFs through 00z Monday Evening)
Issued at 546 PM CST Sun Feb 15 2015
Band of snow stretching from north of KCOU...north of KSTL...to
around KSLO will continue to increase in coverage this evening
while moving east-southeast. Some showery precipitation south of
the band is being reported as a snow pellets or even some sleet.
IFR conditions with vsbys at or below 1SM are being reported with
the band with mostly VFR vsbys to the north and south of the band.
Another area of snow will develop along and south of the I-70
corridor between 03Z and 09Z tonight which will bring moderate to
heavy snow to these areas as well. Expect IFR conditions to
prevail with visibilities at or below 1SM and ceilings at or below
700 FT. Snow will end from west to east Monday morning into the
early afternoon. As the snow tapers off, expect flight conditions
to improve to MVFR with ceilings most likely hanging between 1000-1900FT.
Specifics for KSTL:
Band of moderate to heavy snow is just north of the STL metro area,
but are seeing increasing radar returns over the past hour in the
vicinity of the terminal. Still think there will be some light
snow or snow grains for the first hour or two and then there the
snow should increase in intensity. Timing on this increasing
intensity is uncertain, but it looks like it should be before 03Z.
Once heavier snow begins, expect IFR vsbys to prevail with
ceilings lowering to IFR as well. Should see snow begin lightening
up overnight with light snow and mvfr conditions continuing into
the late morning or early afternoon. Even after the snow ends, it
looks like ceilings should stay between 1000-1900FT.
Carney
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER STORM WARNING until 6 PM CST Monday FOR Boone MO-Callaway
MO-Cole MO-Crawford MO-Franklin MO-Gasconade MO-Iron MO-
Jefferson MO-Madison MO-Moniteau MO-Montgomery MO-Osage MO-
Reynolds MO-St. Charles MO-St. Francois MO-St. Louis City
MO-St. Louis MO-Ste. Genevieve MO-Warren MO-Washington MO.
WINTER WEATHER ADVISORY until 6 PM CST Monday FOR Audrain MO-
Lincoln MO-Monroe MO-Pike MO-Ralls MO.
IL...WINTER STORM WARNING until 6 PM CST Monday FOR Bond IL-Clinton
IL-Fayette IL-Madison IL-Marion IL-Monroe IL-Randolph IL-
St. Clair IL-Washington IL.
WINTER WEATHER ADVISORY until 6 PM CST Monday FOR Calhoun IL-
Greene IL-Jersey IL-Macoupin IL-Montgomery IL-Pike IL.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED
NWS BILLINGS MT
837 PM MST SUN FEB 15 2015
.UPDATE...
FIELD REPORTS INDICATED THAT SNOW BEGAN IN RED LODGE AND THE
SURROUNDING AREAS A LITTLE AFTER 600 PM LOCAL TIME. THE TRICKIEST
PART OF THIS FORECAST PACKAGE HAS BEEN MONITORING THE AVIATION
IMPACTS FOR KLVM. CEILINGS HAVE BEEN UP AND DOWN AND THE SNOW IN
AND OUT OF THERE...WHICH HAS MADE IT DIFFICULT TO PIN DOWN THE
SPECIFICS FOR ANY GIVEN PERIOD. MEANWHILE...WINTER WEATHER
ADVISORIES FOR THE BEARTOOTH/RED LODGE FOOTHILLS AND THE BIG HORN
MOUNTAINS REMAIN IN TACT...AS ADDITIONAL ACCUMULATIONS ON THE
ORDER OF 2 TO 4 INCHES IN THOSE AREAS ARE LIKELY OVERNIGHT.
SINGER
&&
.SHORT TERM...VALID FOR MON AND TUE...
THE SHORT TERM LOOKS IN GOOD SHAPE. HAVE NOT MADE MANY CHANGES.
DID REDUCE QPF OVER THE MOUNTAINS SLIGHTLY AND THUS REDUCED THE
SHOW FALL MAYBE AN INCH. MODELS WERE SHOWING SLIGHTLY LOWER
AMOUNTS. AM CONTINUING THE ADVISORIES FOR THE FOOTHILLS AND
BIGHORNS. WHILE THE HRRR SHOWS SOME GOOD BANDS OF HIGHER
PRECIP...THE CURRENT ADVISORY LOOKS GOOD. THE ONE EXCEPTION IS
THE PARADISE VALLEY. HOWEVER...LATEST RUNS KEEP IT JUST EAST IN
THE BEARTOOTHS. WILL CONTINUE TO MONITOR. ALSO POSSIBLE THAT A
CONVECTIVE BAND COULD PRODUCE HIGHER AMOUNTS NEARING WARNING
CRITERIA...BUT AGAIN THE UNCERTAINTY DOES NOT WARRANT ANYTHING AT
THE MOMENT.
GOING INTO TOMORROW...A NORTH SOUTH ORIENTED JET WILL SHIFT
EAST...BISECTING THE AREA. THIS WILL PUT THE EASTERN ZONES IN THE
MORE FAVORABLE LEFT EXIT REGION. WITH THIS INCREASED LIFT...RAISED
POPS SLIGHTLY. PRECIP REMAINS FAIRLY LIGHT SO SNOW TOTALS ARE ONLY
A COUPLE OF INCHES...THOUGH THE BIGHORN MOUNTAINS COULD STILL SEE
UP TO 4 MORE INCHES.
AS FOR TEMPERATURES...NOT MUCH HAS CHANGED. OVERNIGHT MONDAY AND
TUESDAY THE EASTERN PLAINS WILL STILL LIKELY SEE TEMPERATURES DROP
INTO THE SINGLE DIGITS. REIMER
.LONG TERM...VALID FOR WED...THU...FRI...SAT...SUN...
THE PERSISTENT NORTHWEST FLOW WILL CONTINUE TO DOMINATE THE
WEATHER PATTERN INTO NEXT WEEKEND. OUR REGION OF THE NORTHERN
ROCKIES WILL CONTINUE TO BE THE BATTLE GROUND BETWEEN THE TROUGH
AND COLD AIRMASS TO OUR EAST AND RIDGE/WARM CONDITIONS TO OUR
WEST. THIS WILL KEEP THE REGION UNSETTLED...BUT NO HIGH IMPACT
EVENTS ANTICIPATED.
WED/THU WILL SEE ANOTHER ROUND OF WARMER AND DRIER CONDITIONS
SHIFT EAST. THERE COULD BE SOME LIGHT WARM AIR ADVECTION PRECIP
INTO EASTERN MONTANA WEDNESDAY AS THE COLDEST AIR RETREATS.
SIGNIFICANT TEMPERATURE DIFFERENCES COULD BE NOTED FROM CENTRAL TO
EASTERN AREAS WHERE THE COLD AIR TRIES TO HANG ON THE LONGEST. THE
NEXT WAVE OF ENERGY DROPS SOUTHEAST ACROSS THE AREA FRIDAY. THIS
WILL SHIFT THE COLD AND UNSETTLED WEATHER BACK INTO THE REGION
BEGINNING FRIDAY AND LINGERING INTO SUNDAY. LIGHT SNOW OR AT
TIMES A RAIN/SNOW MIX WILL OCCUR FROM FRIDAY THROUGH SUNDAY.
FRIEDERS
&&
.AVIATION...
AN UNSTABLE NORTHWEST FLOW WILL BRING PERIODS OF SNOW SHOWERS
ACROSS THE REGION INTO MONDAY WITH A RAIN/SNOW MIX IN THE LOWER
ELEVATIONS. EXPECT RAPIDLY CHANGING FLIGHT CONDITIONS WITH THESE
SHOWERS FROM VFR TO IFR IN SHORT PERIODS OF TIME. MORE WIDESPREAD
IFR CONDITIONS ARE LIKELY IN AND NEAR THE MOUNTAINS...INCLUDING
KSHR AND KLVM. MOUNTAINS WILL BE MOSTLY OBSCURED OVER THE NEXT 24
HOURS. FRIEDERS
&&
.PRELIMINARY POINT TEMP/POPS...
MON TUE WED THU FRI SAT SUN
-----------------------------------------------------------
BIL 026/038 023/037 024/043 028/054 033/046 027/038 022/039
53/J 31/B 11/B 01/B 23/W 33/S 22/S
LVM 023/036 020/040 027/053 035/053 034/048 028/040 023/040
74/J 21/B 00/N 01/N 23/W 33/O 22/O
HDN 025/038 021/035 019/041 026/052 028/046 023/036 018/039
46/J 52/J 11/E 01/B 23/W 33/S 22/S
MLS 023/033 012/024 010/034 020/045 025/040 019/031 015/035
39/J 51/B 12/J 01/B 22/W 22/S 22/S
4BQ 023/035 016/028 013/034 022/048 026/042 022/033 017/038
47/J 62/J 12/W 01/B 12/W 32/S 22/S
BHK 021/029 005/017 002/024 013/040 022/036 015/027 011/032
39/J 51/N 11/E 01/B 22/J 22/S 22/S
SHR 022/033 019/031 017/040 023/051 026/044 022/034 016/036
66/J 63/J 12/J 00/B 23/W 43/S 22/S
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...WINTER WEATHER ADVISORY IN EFFECT UNTIL 6 AM MST MONDAY FOR
ZONES 41-56-66.
WY...WINTER WEATHER ADVISORY IN EFFECT UNTIL 6 AM MST TUESDAY FOR
ZONE 98.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION...UPDATED
NWS BILLINGS MT
919 AM MST SAT FEB 14 2015
.UPDATE...
MADE A FEW TWEAKS TO THE POPS...MAINLY TO LOWER THEM THIS
AFTERNOON OVER THE MOUNTAINS. CURRENT HIRES MODELS AND RAP DO NOT
SUPPORT MUCH UNTIL AFTER 00Z. EXTENDED THE PATCHY FOG UNTIL 18Z.
WEBCAMS ACROSS THE EASTERN PART OF THE AREA STILL SHOW SOME FOG
REMAINING. REIMER
&&
.SHORT TERM...VALID FOR TDY AND SUN...
AN UNSETTLED WEATHER PATTERN WILL BEGIN DEVELOPING TONIGHT...BUT
IN THE MEANTIME SOME AREAS WILL HAVE ONE MORE VERY WARM DAY TODAY.
TODAY...A SHALLOW COLD FRONT HAS BEEN MAKING A SLOW WESTWARD PUSH
OVERNIGHT AND LOW CLOUDS /STRATUS/ AND LIGHT FOG IN ITS WAKE HAVE
MADE IT TO MILES CITY AS OF 10 UTC. THE FRONTAL ZONE SHOULD STILL
MAKE IT TO NEAR HYSHAM AND COLSTRIP BY DAYBREAK PER RECENT MODEL
GUIDANCE...AND WE WILL CARRY PATCHY FOG IN THE FORECAST THROUGH 15
UTC ALONG AND EAST OF IT BASED ON VISIBILITY REDUCTIONS AS LOW AS
2SM OBSERVED OVERNIGHT. THE 00 UTC GUIDANCE AND MORE CONTEMPORARY
HRRR SIMULATIONS ALL SHOW THE FRONT RETREATING BACK EASTWARD TODAY
WITH 850-MB TEMPERATURES BACK UP AROUND +10 C IN SOUTH CENTRAL MT
THIS AFTERNOON...YIELDING HIGHS OVER 60 F AGAIN IN MANY AREAS WITH
MIXING TO ALMOST 750-MB ONCE MORE ON FORECAST SOUNDINGS. THE DAILY
RECORD HIGHS AT BILLINGS AND LIVINGSTON ARE BOTH 59 F AND BOTH ARE
LIKELY TO BE BROKEN. HOWEVER...WE DIDN/T GO ALL-IN WITH THE FULL
AMOUNT OF WARMING SHOWN BY THE 00 UTC BIAS-CORRECTED ECMWF /WHICH
VERIFIED VERY WELL THE LAST TWO DAYS/ SINCE MORE CLOUD COVER WILL
LIKELY EXIST TODAY. A STRONG THERMAL GRADIENT WILL EXIST IN SOUTH-
EASTERN MT WHERE THE FRONT IS NOT EXPECTED TO REACH MILES CITY AND
BROADUS UNTIL LATE DAY...AND IT WILL LIKELY NEVER GET TO BAKER...
WHERE FORECAST HIGHS ARE ONLY IN THE 20S F.
WE DID GO AHEAD AND REMOVE PRECIPITATION CHANCES IN MOST AREAS FOR
TODAY WITH WEAKER QG-FORCING ALOFT IN THE 00 UTC GUIDANCE THAN WE
SAW AT THIS TIME YESTERDAY...ALONG WITH RELATIVELY DRY MID-LEVELS.
TONIGHT...A SHORTWAVE TROUGH IN NORTHWEST FLOW WILL CROSS THE AREA
AND SUPPORT SOME CHANCE OF RAIN AND SNOW SHOWERS. THE 00 UTC MODEL
SUITE SUGGESTED A BURST OF NOTABLE QG-FORCING CENTERED ACROSS THE
FOOTHILLS OVERNIGHT...AND WE HAVE ACCORDINGLY INCREASED POPS WITH
AN INCH OF SNOW NOW ADVERTISED TONIGHT IN PLACES LIKE RED LODGE.
SUNDAY INTO SUNDAY NIGHT....A COOLER AIR MASS WILL BE IN PLACE IN
THE WAKE OF TONIGHT/S SHORTWAVE TROUGH...AND BY THE AFTERNOON AND
EVENING ANOTHER SHORTWAVE TROUGH WILL AFFECT THE AREA. THE 00 UTC
ECMWF DID BACK OFF ON THE STRENGTH OF THIS FEATURE...BUT WE CHOSE
TO CAUTIOUSLY SET THAT IDEA ASIDE SINCE IT/S AN OUTLIER SOLUTION.
THUS...WE ARE STILL EXPECTING RAIN AND MORESO SNOW SHOWERS ACROSS
AT LEAST SOUTH CENTRAL MT AND NORTH CENTRAL WY BY SUNDAY NIGHT. A
STEEP-LAPSE-RATE-ENVIRONMENT COULD YIELD CONVECTIVE ENHANCEMENT OF
SNOW SHOWERS...ESPECIALLY ALONG THE FOOTHILLS LIKE AT RED LODGE.
THE FOOTHILLS ARE FAVORED FOR HIGHER SNOW TOTALS IN A PATTERN LIKE
THIS AND WE ARE ADVERTISING 3 TO 6 INCHES IN THE FORECAST...WHICH
WILL LIKELY REQUIRE WINTER WEATHER HEADLINES AT SOME POINT. POPS
WERE ALSO INCREASED INTO THE LIKELY CATEGORY IN BILLINGS BY SUNDAY
NIGHT...BUT WE ARE CARRYING AN INCH OR LESS OF SNOW IN THE CITY AT
THIS POINT BASED ON THE 00 UTC MULTI-MODEL CONSENSUS. SCHULTZ
.LONG TERM...VALID FOR MON...TUE...WED...THU...FRI...
AN ACTIVE NORTHWEST FLOW WILL PREVAIL THROUGH THE EXTENDED PERIOD
WITH A STRONG RIDGE ALOFT BECOMING A FIXTURE ALONG THE PACIFIC
COAST. SHORTWAVE WITH 140KT H3 JET WILL BRING A GOOD CHANCE OF
SNOW SHOWERS TO OUR CENTRAL AND EAST PARTS MONDAY AND MONDAY
NIGHT. INSTABILITY WILL BE SHALLOWER THAN SUNDAY BUT INTERSECT
THE DENDRITIC LAYER...AND FOCUS OF SNOW SHOWER ACTIVITY SHOULD BE
ALONG INVERTED SFC-TROF AND IN NW FLOW UPSLOPE AREAS. CURRENT
INDICATIONS ARE FOR A 1 TO 3 INCH SNOWFALL FOR THE HIGHER TERRAIN
SOUTHEAST OF BILLINGS INCLUDING THE LIKES OF THE WOLF
MOUNTAINS...LAME DEER DIVIDE AND ABERDEEN HILL. HAVE RAISED POPS
AND SNOW AMTS IN THESE AREAS.
PCPN SHOULD TAPER OFF IN SOUTHEAST MT ON TUESDAY. THERE IS
POTENTIAL FOR ANOTHER PERIOD OF MOSTLY LIGHT SNOW EAST OF BILLINGS
WITH ISENTROPIC ASCENT TUESDAY NIGHT INTO WEDNESDAY...AS DOWNSLOPE
WARMING BECOMES DOMINANT IN OUR WEST AT THE SAME TIME. WILL
SUSTAIN LOW POPS TO COVER THIS POTENTIAL.
AFTER WHAT SHOULD BE A DRY AND WARMER PERIOD WEDNESDAY NIGHT TO
THURSDAY AS RIDGE AXIS SHIFTS EAST...SOME MODEL DISAGREEMENT
EXISTS HERE...IT APPEARS WE WILL SEE MORE SHORTWAVE ENERGY FROM
THE NW AND ANOTHER SURGE OF COLD ADVECTION BY THE END OF THE WEEK.
WILL KEEP CLIMO POPS FOR DAYS 7/8 TO COVER THIS FOR NOW.
AS FOR TEMPERATURES...LOOKS LIKE A COUPLE DAYS OF BELOW NORMAL
CONDITIONS FOR MOST OF OUR AREA MONDAY AND TUESDAY...WITH OUR
EAST REMAINING COLDEST PER PROXIMITY TO VERY COLD AIR SURGING INTO
THE NORTHERN PLAINS. 850MB TEMPS COOL TO THE MID TEENS BELOW ZERO
IN OUR FAR EAST BY TUESDAY...ALONG WITH A GUSTY NW WIND...SO WILL
BE QUITE CHILLY FOR PLACES SUCH AS BAKER AND EKALAKA WITH BELOW
ZERO WIND CHILLS. WARMUP WILL BEGIN ON WEDNESDAY...ESPECIALLY IN
OUR WEST AS DOWNSLOPE FLOW INCREASES...BUT SHOULD POINT OUT THAT
THE GFS HAS TRENDED TOWARD HOLDING THE SFC RIDGE IN A BIT LONGER
THAN PREVIOUS RUNS...AND INDEED THE ENSEMBLE GUIDANCE SHOWS A
PRETTY GOOD SPREAD IN TEMPS ON WEDNESDAY. WARMING TREND SHOULD
CONTINUE THURSDAY IF NOT INTO FRIDAY AS WELL...BUT AS ALREADY
MENTIONED WOULD EXPECT COOLING BY THE END OF THE WEEK.
JKL
&&
.AVIATION...
MVFR WILL PREVAIL IN EASTERN MT INTO KMLS AND KBHK WITH SOME LOW
CLOUDS AND FOG...MAINLY THIS MORNING. VFR WILL PREVAIL OTHERWISE
TODAY WITH SCT/BKN MID AND HIGH LEVEL CLOUDINESS. A COLD FRONT
WILL DROP SOUTH ACROSS THE REGION TONIGHT BRING INCREASED SHOWER
ACTIVITY AND LOCAL MVFR CONDITIONS...ESPECIALLY NEAR THE
FOOTHILLS...ALONG WITH FREQUENT MOUNTAIN OBSCURATIONS. FRIEDERS
&&
.PRELIMINARY POINT TEMP/POPS...
TDY SUN MON TUE WED THU FRI
-------------------------------------------------------
BIL 063 033/046 027/037 020/035 022/043 028/049 031/046
1/N 25/W 64/J 32/J 11/B 11/B 22/W
LVM 062 033/044 023/036 018/041 023/050 034/049 032/048
1/N 55/W 63/J 21/B 11/B 11/B 22/W
HDN 063 029/047 026/035 016/034 018/041 026/049 026/046
1/E 24/W 45/J 42/J 22/J 11/B 22/W
MLS 044 025/043 024/032 009/026 014/034 020/042 023/040
1/E 21/B 35/J 42/J 22/J 11/E 22/J
4BQ 050 027/044 024/032 015/026 014/034 022/047 025/042
1/E 21/E 35/J 53/J 22/J 11/B 22/W
BHK 027 016/038 021/027 006/019 007/025 014/038 020/036
2/J 21/B 35/J 21/B 22/J 11/E 22/J
SHR 057 031/042 023/033 018/031 015/040 023/047 025/044
1/E 53/W 75/J 53/J 22/J 11/B 22/W
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION...UPDATED
NWS BILLINGS MT
912 PM MST FRI FEB 13 2015
.UPDATE...
JUST SOME MINOR FORECAST ADJUSTMENTS FOR THE UPDATE THIS EVENING.
DEWPOINT GRADIENT AND ONSET OF LOW CLOUDS PLACED THE BACKDOOR COLD
FRONT OVER W ND/FAR NE MT AT 04Z. RADAR SHOWED PRECIPITATION WAS
BACK OVER CENTRAL ND. OBSERVATIONS SHOWED MID CLOUDS WILL ARRIVE
OVER THE EASTERN ZONES BEFORE LOW CLOUDS MOVE IN...SO DESPITE SOME
EXPECTED HIGHER HUMIDITIES IN THE E...WILL LEAVE OUT MENTION OF
FOG. WILL KEEP AREA DRY OVERNIGHT AS WELL. RAISED TEMPERATURES
FROM KBIL W AS 850 MB TEMPERATURES WILL BE SIMILAR TO THIS
MORNING/S READINGS BY 12Z SAT...AND CIRRUS WILL ALSO HOLD
TEMPERATURES UP. IN ADDITION...CURRENT READINGS WERE IN THE 40S
AND 50S. MADE SLIGHT ADJUSTMENTS TO WINDS AND SKY COVER BASED ON
LATEST OBSERVED AND MODEL TRENDS.
SAT CONTINUED TO LOOK MAINLY DRY AND WARM AS BACKDOOR FRONT
PUSHES BACK TO THE E. SHORTWAVES IN NW FLOW WILL BRING INCREASING
CHANCES FOR PRECIPITATION TO THE AREA SAT NIGHT THROUGH SUN NIGHT
AS WELL AS A COOLER AIRMASS. ARTHUR
&&
.SHORT TERM...VALID FOR SAT AND SUN...
...AFTER A VERY PLEASANT AND WARM DAY TODAY...THE WEATHER WILL GET
MORE INTERESTING BY THE END OF THE HOLIDAY WEEKEND...
DAYTIME HIGH TEMPERATURES THIS AFTERNOON ARE APPROACHING NEAR
RECORD VALUES DUE TO STRONG MIXING IN THE LOWER PORTIONS OF THE
ATMOSPHERE. 1 PM TEMPERATURES ACROSS THE REGION WERE GENERALLY IN THE
UPPER 50S AND LOWER 60S AND ON THE RISE DUE TO FAIRLY PERSISTENT
SURFACE WINDS.
BY TONIGHT...MODELS ARE IN GOOD AGREEMENT IN BRINGING A BACK DOOR
COLD FRONT WITH THE AIR BEHIND IT ORIGINATING FROM SOUTHERN
SASKATCHEWAN AND MANITOBA. THERE IS NOT ANY DOUBT IT WILL GET
COOLER IN THE OUR FAR EASTERN ZONES...BUT THERE IS UNCERTAINTY IN HOW
FAR WEST THE COLD AIR WILL ACTUALLY GET. THERE IS A CHANCE SOME
LOCATIONS OUT EAST...BAKER...EKALAKA...COULD SEE HIGHS HOVERING
AROUND 30 DEGREES TOMORROW...WHILE OTHER LOCATIONS SUCH AS
BILLINGS SEE HIGHS WELL INTO THE 50S. WINDS WILL SHIFT EASTERLY
WITH THE ONSET OF THIS BAROCLINIC ZONE...AND BRING SOME CLOUD
COVER WITH IT. HRRR BUFKIT SOUNDING ANALYSIS SUGGESTS THE EASTERLY
FLOW WILL BRING DIMINISHED VISIBILITIES TO KMLS AND KBHK BY
SATURDAY MORNING. HOWEVER...THE COLDEST AIR WILL REMAIN WELL TO
THE NORTH AND EAST OF THE BILLINGS CWA.
FOR SATURDAY NIGHT INTO SUNDAY...THINGS GET A LITTLE MORE
INTERESTING AS THE AFOREMENTIONED LINGERING FRONT INTERACTS WITH
AN UPPER LEVEL SHORTWAVE MOVING IN FROM THE NORTHWEST. THE MAIN
IMPACT WILL NOW TURN TO SNOW ACCUMULATIONS IN THE BEARTOOTH
FOOTHILLS. BUFKIT SOUNDING ANALYSIS HINTS AT A BRIEF PERIOD OF
UPSLOPE FLOW ACCOMPANIED WITH A FAIRLY UNSTABLE AIR MASS BY
TOMORROW AFTERNOON...WHICH COULD GENERATE SEVERAL INCHES OF SNOW
FOR AREAS NEAR NYE AND RED LODGE. TAKING A LOOK AT THE CIPS
ANALOGS FOR SIMILAR CASES...IT FURTHER BACKS THE THEORY THAT THE
FOOTHILL LOCATIONS ARE THE PREFERRED AREA FOR POTENTIAL
ACCUMULATING SNOW. EITHER WAY...DECIDED TO HOLD OFF ON ISSUANCE
OF A WINTER WEATHER ADVISORY AT THIS FORECAST PACKAGE...AS AMOUNTS
ARE STILL NOT SOLIDIFIED AT THIS TIME. WOULD GUESS ANYWHERE FROM
3-6 INCHES IS POSSIBLE WHEN ALL IS SAID AND DONE. SINGER
.LONG TERM...VALID FOR MON...TUE...WED...THU...FRI...
EXTENDED PERIOD BEGINS ON MONDAY WITH THE NOSE OF A STRONG UPPER
LEVEL JET DIVING INTO NORTHERN IDAHO. DURING THE DAYS TO
FOLLOW...THIS JET STREAK WILL SLIDE TO THE EAST AND ASSIST THE
PROGRESSION OF A SERIES OF SHORTWAVES THROUGH THE REGION. THERE
REMAINS THE POTENTIAL FOR SOME ACCUMULATING SNOW IN BOTH THE BIG
HORN AND BEARTOOTH RANGES...AS THE ORIENTATION OF THE MAIN UPPER
LEVEL FORCING FAVORS THOSE PARTICULAR AREAS THE MOST.
AFTER A BRIEF COOLDOWN EARLY IN THE WEEK...TEMPERATURES WILL
AGAIN BECOME SOMEWHAT MILD AFTER MONDAY. THE FORECAST REMAINS
UNCERTAIN AFTER THAT...SO LEFT THE REMAINING FORECAST AS IS UNTIL
MODELS COME INTO BETTER AGREEMENT. SINGER
&&
.AVIATION...
MVFR TO IFR CONDITIONS DUE TO LOW CEILINGS WILL MOVE INTO AREAS
FROM KMLS E AND SE OVERNIGHT AND CONTINUE THROUGH EARLY SAT
MORNING. PATCHY FOG IS ALSO POSSIBLE IN THESE AREAS. OTHERWISE...VFR
WILL PREVAIL ACROSS THE AREA THROUGH SAT EVENING. MOUNTAIN
OBSCURATIONS WILL INCREASE SAT EVENING. ARTHUR
&&
.PRELIMINARY POINT TEMP/POPS...
SAT SUN MON TUE WED THU FRI
-----------------------------------------------------------
BIL 038/059 034/042 027/036 018/037 024/043 028/049 031/046
01/E 25/W 54/J 32/J 11/B 11/B 22/J
LVM 045/051 034/039 026/036 018/040 023/048 029/049 032/048
01/N 34/W 53/J 21/B 11/N 11/N 22/J
HDN 033/053 029/043 024/035 013/034 018/041 023/049 026/045
01/E 24/W 44/J 32/J 22/W 11/B 22/W
MLS 028/038 024/042 021/030 009/026 015/036 019/042 024/040
12/W 21/E 33/J 21/B 22/J 11/B 22/J
4BQ 029/043 027/040 023/033 013/028 017/039 020/047 026/043
12/W 21/E 34/J 31/B 22/W 11/B 22/J
BHK 016/024 017/036 020/027 005/021 010/032 017/038 021/037
12/J 21/N 34/J 21/B 22/J 11/E 12/J
SHR 029/054 029/040 023/032 013/031 016/040 020/047 025/043
01/B 33/W 55/J 42/J 22/W 21/B 22/W
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS BUFFALO NY
959 AM EST SAT FEB 14 2015
.SYNOPSIS...
A STRENGTHENING LOW WILL BRING SNOW AND BLOWING SNOW TODAY AND
TONIGHT BEFORE THE COLDEST AIR OF THE SEASON SURGES INTO THE AREA
FOR SUNDAY AND MONDAY. DAYTIME HIGHS ON SUNDAY MAY NOT EVEN GET
ABOVE ZERO...WITH DANGEROUSLY COLD WIND CHILLS. THE COLD WEATHER
WILL CONTINUE INTO NEXT WEEK WITH MORE BELOW NORMAL TEMPERATURES.
&&
.NEAR TERM /THROUGH TONIGHT/...
THE NEXT ROUND OF WINTRY WEATHER MAY NOT BE THE HEAVIEST SNOW OF THE
SEASON...BUT THE SNOW...BLOWING SNOW...AND COLD TEMPERATURES WILL
BE A LIFE THREATENING COMBINATION. IF A VEHICLE BECOMES DISABLED
FROM THE SNOWY CONDITIONS...PASSENGERS WILL HAVE TO CONTEND WITH
DANGEROUSLY COLD WIND CHILLS.
THE EXTREME CONDITIONS WILL NOT START UNTIL A STRENGTHENING LOW
PRESSURE SYSTEM AND AN ASSOCIATED ARCTIC FRONT MOVES ACROSS THE
REGION. STRONG WINDS AND BITTERLY COLD ARCTIC AIR WILL POUR INTO THE
REGION BEHIND THIS SYSTEM.
AT 1000 AM...BUFFALO RADAR SHOWING A CONVERGENCE BOUNDARY ACROSS
NORTHERN ERIE COUNTY WHICH IS PRODUCING A BAND OF VERY HEAVY
SNOW...WITH SNOWFALL RATES UP TO 3 INCHES PER HOUR. UNTIL THE FRONT
REACHES THE AREA TOWARD NOON THIS BAND WILL REMAIN NEARLY STATIONARY.
A VIGOROUS UPPER LOW AND WEAKER SURFACE REFLECTION WILL DIVE ACROSS
THE REGION TODAY...WITH THE SURFACE LOW EVENTUALLY DEEPENING
RAPIDLY ONCE IT REACHES THE NEW ENGLAND COAST TONIGHT. WINDS WILL
INCREASE RAPIDLY WITH THE PASSAGE OF THIS LOW AND AN ASSOCIATED
FRONTAL BOUNDARY...WITH A QUICK BURST OF SNOW EXPECTED ALONG THIS.
MEANWHILE...NORTHWEST WINDS GUSTING TO 40 MPH WILL RESULT IN
BLOWING SNOW JUST BEHIND THE WIND SHIFT. A HRRR WEIGHTED
CONSENSUS OF MESOSCALE GUIDANCE BRINGS THIS INTO BUF-JHW AROUND NOON
AND ROC-ELZ AROUND 2 PM.
IN ADDITION TO LIFT WITH THE FRONT...THERE WILL BE A SMALL AREA
OF UPPER LEVEL DIFFLUENCE HEAD OF THE 500 MB LOW WHICH TRAILS THE
SURFACE LOW. GUIDANCE DIFFERS A BIT ON WHERE THIS WILL BE...WITH
A CONSENSUS FORECAST BRINGING ENHANCED SNOWFALL TO THE FINGER LAKES
REGION AND INTO OSWEGO COUNTY LATE THIS AFTERNOON AND EARLY
EVENING. THIS IS LIKELY TO BRING SNOWFALL RATES OF 1 TO 2 INCHES
AN HOUR AND PRODUCE NEAR WHITEOUT CONDITIONS SINCE IT WILL COINCIDE
WITH GUSTY SURFACE WINDS.
OUTSIDE OF THIS AREA...EXPECT A BRIEF LULL IN SNOW INTENSITY LATE
AFTERNOON AND EARLY EVENING WITH WESTERN NEW YORK UNDERNEATH THIS
CLOSED UPPER LOW. ONCE THIS UPPER LOW MOVES TO OUR EAST...THERE
WILL BE A REINFORCING SHOT OF COLD AIR AND AN UPTICK IN WINDS.
THIS SHOULD ENERGIZE LAKE EFFECT SNOWS SOUTH OF LAKE
ONTARIO...WITH AMPLE MOISTURE BENEATH THE BACK OF THE UPPER LOW
TO OFFSET THE STRONG WIND SPEEDS. THIS IS WHEN BITTERLY COLD WIND
CHILLS WILL COMBINE WITH SNOW AND BLOWING SNOW TO CREATE THE MOST
DANGEROUS CONDITIONS IN MOST AREAS. WIND CHILLS WILL PLUMMET TO 25
TO 35 BELOW LATE TONIGHT INTO SUNDAY MORNING. THE STRONGEST WINDS
AND MOST SIGNIFICANT BLOWING SNOW WILL BE JUST SOUTH OF LAKE
ONTARIO WHERE NEAR WHITEOUT CONDITIONS ARE POSSIBLE.
OVERALL...THE LATEST FORECAST HAS ONLY MADE MINOR ADJUSTMENTS TO
STORM TOTAL SNOWFALL. WITH THE STRONG WINDS AND DEEP
MOISTURE...EXPECT UPSLOPING WELL SOUTH OF THE LAKE ONTARIO SHORELINE
TO ENHANCE SNOW TOTALS A BIT. THE GREATEST AMOUNTS SHOULD BE FROM
ROCHESTER TOWARD SYRACUSE...WHERE 8 TO 14 INCHES IS FORECAST. HAVE
ALSO TWEAKED UP SNOWFALL AMOUNTS FOR BUFFALO TO ACCOUNT FOR THE
LOCALIZED CONVERGENCE BOUNDARY WHICH SETTLED ACROSS THE CITY EARLY
THIS MORNING.
&&
.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
ONE OF THE COLDEST DAYS IN DECADES WILL START THIS TIME PERIOD AS A
LOBE OF -25C TO -27C AIR AT 850 HPA REMAINS ACROSS THE REGION...WITH A
BITING NORTHWEST WIND. TO ADD TO THE EXTREME BITTERNESS...SNOW
SHOWERS WILL BE FALLING THROUGH THE DAY SOUTH OF LAKE ONTARIO.
FOR THE EXTREME TEMPERATURES...
SUNDAY NORTHWEST WINDS WILL CONTINUE TO BRING A FRESH COLD AIRMASS
ACROSS OUR REGION...WITH -25C TO -27C 850 HPA TEMPERATURES AND CAA
ADVECTION THROUGH THE DAY BRINGING -25C AIR AS LOW AS JUST A FEW
HUNDRED FEET ABOVE THE SURFACE. NAEFS MEAN TEMPERATURE AND RETURN
INTERVALS GIVE THIS 850 HPA TEMPERATURES AT LEAST A ONCE IN 10 YEAR
OCCURRENCE. GIVEN THAT TEMPERATURES OF -26C OR LOWER HAVE BEEN
MEASURED ONLY 12 TIMES IN THE MONTH OF FEBRUARY VIA BUFFALO BALLOON
SOUNDINGS (TAKEN TWICE A DAY) SINCE 1948...WE ALSO VERIFY THAT THIS
AIRMASS OCCURS ABOUT ONCE EVERY DECADE OR SO. IN FACT THE COLDEST
850 HPA TEMPERATURE MEASURED VIA BUFFALO BALLOON SOUNDING (TAKEN AT
12Z AND 00Z) IN THE MONTH OF FEBRUARY IS -27.8C BACK ON 12Z FEBRUARY
1, 1971.
THE ARCTIC AIRMASS WILL CONTINUE THE SUBFREEZING TEMPERATURES
THROUGH THE DAY ON SUNDAY...WITH DAYLIGHT HIGHS 0F TO -5F ACROSS THE LAKE
PLAINS AND DOWN TO THE NEGATIVE TEENS IN THE SOUTHERN TIER AND UPON
THE TUG HILL REGION. THESE SUBFREEZING TEMPERATURES WILL ONLY DIP
FARTHER DOWN SUNDAY NIGHT AS HIGH PRESSURE FROM THE CENTRAL GREAT
LAKES BUILDS TOWARDS THE REGION. AS SKIES CLEAR AWAY FROM THE
SOUTHERN LAKE ONTARIO SHORELINE...AND WINDS BECOME LIGHT AND
VARIABLE...SURFACE AIR TEMPERATURES OVER A FRESH AND DEEP SNOWPACK
WILL PLUMMET TO NEAR 10 BELOW ACROSS THE LAKE PLAINS...WITH
WIDESPREAD -20S IN THE SOUTHERN TIER AND PERHAPS AS LOW AS -30F
BELOW IN THE NORTH COUNTRY...INCLUDING THE WATERTOWN AIRPORT. THESE
AIR TEMPERATURES LATE SUNDAY NIGHT AND EARLY MONDAY MORNING WILL
DROP TO NEAR RECORD LEVELS FOR THE DATE OF FEBRUARY 16TH. PLEASE SEE
CLIMATE SECTION BELOW FOR VALUES.
FOR THESE SUNDAY NIGHT TEMPERATURES TO COME TO FRUITION...OUR WINDS
MUST BE LIGHT...AND A LIGHT WIND WILL ONLY NUDGE WIND CHILLS LOWER.
WIND CHILLS SUNDAY NIGHT WILL RANGE FROM -25 TO -35 BELOW...AND
ADDITIONAL HEADLINES WILL LIKELY BE NEEDED SUNDAY NIGHT FOR THESE
VERY LOW WIND CHILLS. IF WINDS WERE TO REMAIN STEADY AROUND 10
MPH...OVERNIGHT LOWS WILL LIKELY NOT BE AS LOW...THOUGH WITH THE
STRONGER WINDS WIND CHILLS VALUES WILL STILL BE IN THE -25 TO -35
BELOW RANGE.
MONDAY HIGH PRESSURE WILL ADVANCE ACROSS THE EASTERN GREAT LAKES
REGION. WARMING ALOFT WITH 850 HPA TEMPERATURES RISING TO THE
NEGATIVE TEENS WILL ALLOW FOR MANY AREAS TO RISE ABOVE 0F FOR A FEW
HOURS. THE LIGHT WINDS AND VERY LOW MIXING HEIGHTS WILL PROBABLY
KEEP MOST AREAS BELOW 5F THOUGH.
AS THIS HIGH PRESSURE SCOOTS EASTWARD MONDAY NIGHT A LIGHT SOUTHERLY
FLOW WILL DEVELOP...FIRST ACROSS WESTERN NEW YORK AND LATER ACROSS
THE NORTH COUNTRY. MOST AREAS ACROSS WNY WILL DROP BACK TO NEAR
0F...WHICH IS NOT MUCH OF A DROP CONSIDERING DAYTIME HIGHS WILL ONLY
BE IN THE LOW SINGLE DIGITS DURING THE DAYTIME. TO THE EAST WHERE
THE SOUTHERLY FLOW WILL DEVELOP LATER OVERNIGHT TEMPERATURES WILL
LIKELY DROP 5 TO PERHAPS 10 DEGREES BELOW ZERO. MID AND HIGH LEVEL
CLOUDS WILL BEGIN TO REACH THE REGION LATE OVERNIGHT...WHICH WILL
ALSO AID IN MAINTAINING LOWS NOT AS HARSH AS THE PRIOR NIGHT.
FOR THE SNOWFALL...
SUNDAY SNOW WILL CONTINUE TO FALL ACROSS THE REGION. ALOFT WEAK
ISENTROPIC UPGLIDE WILL BE PRESENTING ENOUGH LIFT TO GENERATE SNOW
SHOWERS...ACROSS THE TUG HILL EAST OF LAKE ONTARIO...AS WELL AS
AREAS SOUTH OF LAKE ONTARIO. THIS UPGLIDE...SEEN AT THE VERY LOW
255K SURFACE...WILL CONTINUE LIGHT SYNOPTIC SNOW SHOWERS INTO SUNDAY
NIGHT BEFORE THE ISENTROPIC SURFACE FLATTENS WITH THE APPROACHING
AREA OF HIGH PRESSURE.
WITHIN THIS SYNOPTIC SNOW WILL BE BANDS OF HEAVIER SNOWFALL ALONG
THE SOUTHERN LAKE ONTARIO SHORELINE. THIS CURRENT COLD AIRMASS HAS
LIKELY SHRUNK THE OPEN WATERS ON LAKE ONTARIO TO WELL LESS THAN 50
PERCENT...BUT THERE SHOULD STILL BE ENOUGH OPEN WATERS AND THERMAL
HEAT FLUX THROUGH THE THIN ICE TO CREATE LOW LEVEL INSTABILITY AND
ALLOW FOR LAKE EFFECT SNOW SHOWERS TO FALL. A LACKING SNOW CRYSTAL
GROWTH ZONE WILL LIKELY KEEP SNOWFLAKES TO THE SMALL SCALE...WITH 1
TO 2 INCHES OF ADDITIONAL SNOW SUNDAY...DROPPING TO AROUND AN INCH
OVERNIGHT AS LAKE EFFECT SNOWS BECOME THE DOMINATE CHARACTERISTIC OF
THE SNOW...AND EVEN THIS ACTIVITY WILL BE WANING THROUGH THE NIGHT
AS HIGH PRESSURE AND DRIER AIR ADVANCES TOWARDS THE REGION. BACKING
WINDS WILL BRING THESE NOW WEAKEN BANDS OF SNOW TOWARDS SOUTHEAST
AND THEN EAST OF LAKE ONTARIO MONDAY NIGHT WITH ACTIVITY LIKELY
ENDED BY THE END OF MONDAY NIGHT.
BLOWING SNOW WILL STILL BE A MAJOR CONCERN SUNDAY AS NORTHWEST WINDS
CONTINUE THE BLOWING AND DRIFTING OF SNOW ACROSS ROADWAYS. OPEN
AREAS SOUTH OF LAKE ONTARIO WILL EXPERIENCE VERY LOW VISIBILITIES AT
TIMES AS WINDS GUST 30 TO 35 MPH. THESE GUSTS WILL BE LOWER TOWARDS
THE STATE LINE...AND THE MORE FORESTED SOUTHERN TIER WILL LOWER
THE BLOWING AND DRIFTING OF SNOW.
FOR THE NORTH COUNTRY THE BEST CHANCES FOR SNOW WILL COME SUNDAY
WITH THE ISENTROPIC UPGLIDE FLOW. AFTER THIS...THE REGION WILL
LIKELY REMAIN DRY THROUGH THIS TIME PERIOD...WITH MAINLY CLEAR
SKIES.
A CLIMATE NOTE...OUR THREE MAIN CLIMATE SITES (BUFFALO, ROCHESTER,
WATERTOWN) ALL CONSIDER A CLIMATE DAY FROM MIDNIGHT TO MIDNIGHT.
THUS IF AIR TEMPERATURES ARE STILL ABOVE ZERO AT MIDNIGHT LEADING
INTO SUNDAY THESE ABOVE ZERO AIR TEMPERATURES WILL BE CONSIDERED THE
HIGH FOR THE DAY...EVEN IF THE DAYLIGHT HOURS SUNDAY REMAIN WELL
BELOW ZERO. FOR SUNDAY...IT APPEARS MUCH OF THE REGION MAY REMAIN
ABOVE ZERO AT MIDNIGHT...AND THUS THESE VALUES WILL BE THE OFFICIAL
HIGH TEMPERATURES FOR SUNDAY.
ADDITIONAL TEMPERATURE STATS WILL BE FOUND BELOW IN THE CLIMATE
SECTION.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
LATEST MEDIUM RANGE MODELS CONTINUING TO POINT TO A POTENTIAL
SOUTHERN STREAM STORM SYSTEM LIFTING OUT OF THE SOUTHERN PLAINS
TUESDAY...THEN PUSHING UP THE EASTERN SEABOARD INTO NEW ENGLAND
THROUGH WEDNESDAY. THE 00Z GFS CONTINUES TO REMAIN FARTHER WESTWARD
WITH THIS SYSTEM AND ITS TRACK THAN THE 00Z ECMWF. FOR NOW WILL
CONTINUE WITH CHANCES POPS. REGARDLESS OF THE TRACK ANOTHER ROUND OF
COLD AIR WILL FOLLOW BEHIND THE STORM SYSTEM FOR WEDNESDAY THROUGH
FRIDAY...WITH THE POTENTIAL FOR A PROLONGED LAKE EFFECT SNOW EVENT
OFF OF LAKE ONTARIO. WHILE THE NEXT ROUND OF COLD DOES NOT APPEAR AS
POTENT AS THE CURRENT ROUND FOR SUNDAY...IT WILL STILL KEEP
TEMPERATURES WELL BELOW NORMAL.
&&
.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
CONDITIONS WILL GENERALLY DETERIORATE FROM W-E THIS MORNING AS LOW
PRESSURE AND AN ASSOCIATED FRONTAL BOUNDARY DIVE ACROSS THE
REGION. EXPECT WIDESPREAD IFR CONDITIONS...WITH LOCALLY LOWER
CONDITIONS WITH THE WIND SHIFT. GUSTY WINDS WILL MOVE IN BEHIND THE
FRONT WITH BLOWING SNOW ALSO LOWERING VSBY.
AFTER THIS...THERE MAY BE A BRIEF IMPROVEMENT LATE AFTERNOON AND
EARLY EVENING AS SOMEWHAT DRIER AIR MOVES IN. ANY IMPROVEMENT
SHOULD BE SHORT LIVED...WITH ANOTHER BLAST OF EVEN COLDER AIR
FORECAST TO DROP SOUTH OF LAKE ONTARIO BETWEEN 03Z AND 06Z. THIS
WILL ENHANCE LAKE EFFECT SNOW SOUTH OF THE LAKE. THIS COMBINED
WITH BLOWING SNOW WILL LOWER VSBY TO 1SM OR LESS AT BUF/ROC/IAG.
CONDITIONS WILL GRADUALLY IMPROVE LATE TONIGHT AS DRIER AIR
GRADUALLY WORKS IN. DUE TO THE VERY COLD CONDITIONS...EVEN LIGHT
SNOW SHOULD FALL AS VERY SMALL CRYSTALS WHICH WILL LOWER VSBY SIGNIFICANTLY.
OUTLOOK...
SUNDAY...IFR IN LAKE EFFECT SNOW SHOWERS SOUTHEAST OF LAKE
ONTARIO...MVFR ELSEWHERE.
MONDAY...A SLIGHT CHANCE OF MVFR/IFR IN SNOW SHOWERS SOUTHEAST OF
THE LAKES...OTHERWISE VFR.
TUESDAY...CHANCE OF MVFR/IFR IN SNOW SHOWERS.
&&
.MARINE...
WINDS WILL RAPIDLY INCREASE BEHIND A STRONG CLIPPER LOW THIS
AFTERNOON. ARCTIC AIR WILL BUILD ACROSS THE REGION BEHIND THIS AND A
30 KT NW FLOW SHOULD PRODUCE AMPLE WAVE ACTION FOR ANOTHER ROUND OF
HEAVY FREEZING SPRAY ON THE REMAINING OPEN WATERS OF LAKE ONTARIO.
HAVE KEPT WINDS IN THE STRONG SCA RANGE FOR NOW...BUT A FEW GUSTS TO
GALE ARE POSSIBLE WITH THE WIND SHIFT.
FOLLOWING COORDINATION...HAVE ISSUED GALE WARNINGS FOR LAKE
ERIE...WITH A FEW HOURS OF 35 KT WINDS EXPECTED BEHIND THE LOW LATE
THIS AFTERNOON AND EARLY EVENING. WINDS WILL BE STRONGEST ACROSS
CENTRAL AND WESTERN PORTIONS OF LAKE ERIE.
WINDS WILL DIMINISH SUNDAY NIGHT AND MONDAY AS HIGH PRESSURE BUILDS
TOWARD THE LOWER LAKES.
&&
.CLIMATE...
A FEW TEMPERATURE CLIMATE STATS BELOW...
DAILY RECORDS:
SUNDAY, FEBRUARY 15TH
MINIMUM LOW MAXIMUM
BUFFALO -16F (1943) 4F (1943)
ROCHESTER -14F (1943) 4F (1943)
WATERTOWN -30F (1987) 1F (1987)
MONDAY, FEBRUARY 16TH
MINIMUM LOW MAXIMUM
BUFFALO -8F (1904) 0F (1904)
ROCHESTER -7F (2004) -1F (1904)
WATERTOWN -24F (1963) 2F (2003)
ONE WAY TO VIEW THIS UPCOMING COLD OUTBREAK IS TO LOOK AT AVERAGE
TEMPERATURES FOR A DAY (AVERAGE OF MAXIMUM AND MINIMUM TEMPERATURE
FOR THE DAY).
LAST TIME A CLIMATE SITE HAD AN AVERAGE TEMPERATURE BELOW ZERO...
BUFFALO JANUARY 19, 1994 HIGH: -1 LOW: -10 AVERAGE: -5.5F
ROCHESTER JANUARY 14, 2004 HIGH: 4 LOW: -6 AVERAGE: -1.0F
RECENT TIMES A CLIMATE SITE HAD A MINIMUM TEMPERATURE MINUS TEN
OR LOWER...
BUFFALO JANUARY 6, 1996 LOW: -10F
JANUARY 19, 1994 LOW: -10F
JANUARY 21, 1985 LOW: -10F
JANUARY 16, 1984 LOW: -10F
JANUARY 17, 1982 LOW: -16F
ROCHESTER JANUARY 21, 2005 LOW: -10F
JANUARY 10, 2004 LOW: -12F
JANUARY 31, 1994 LOW: -10F
JANUARY 19, 1994 LOW: -11F
JANUARY 16, 1994 LOW: -17F
THOUGH THE POSSIBILITY OF A HIGH TEMPERATURE REMAINING BELOW ZERO
FOR A 24-HR DAY PERIOD IS NOW LESS LIKELY HERE ARE THE LAST TIME
CLIMATE SITES DID ACHIEVE THIS FEAT.
BUFFALO...
COLDEST HIGH TEMPERATURE ON RECORD...
-3 ON FEBRUARY 10, 1899 AND FEBRUARY 11, 1885
LAST TIME HIGH TEMPERATURE WAS BELOW ZERO...
-1 ON JANUARY 19, 1994
ROCHESTER...
COLDEST HIGH TEMPERATURE ON RECORD...
-4 ON JANUARY 17, 1982
LAST TIME HIGH TEMPERATURE WAS BELOW ZERO...
-4 ON JANUARY 17, 1982
WATERTOWN...
COLDEST HIGH TEMPERATURE ON RECORD...
-12 ON JANUARY 3, 1981
LAST TIME HIGH TEMPERATURE WAS BELOW ZERO...
-1 ON JANUARY 22, 2014
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...WINTER STORM WARNING UNTIL 6 PM EST SUNDAY FOR NYZ001>006-
010>014-019-020-085.
WINTER WEATHER ADVISORY FROM 1 PM THIS AFTERNOON TO 6 AM EST
SUNDAY FOR NYZ007-008.
WIND CHILL WARNING FROM 4 PM THIS AFTERNOON TO 10 AM EST
MONDAY FOR NYZ007-008.
WINTER WEATHER ADVISORY UNTIL 6 AM EST SUNDAY FOR NYZ021.
WIND CHILL WARNING FROM 1 PM THIS AFTERNOON TO 10 AM EST
MONDAY FOR NYZ021.
MARINE...GALE WARNING FROM 1 PM THIS AFTERNOON TO 10 PM EST THIS
EVENING FOR LEZ040-041.
HEAVY FREEZING SPRAY WARNING FROM 6 PM THIS EVENING
TO 6 AM EST MONDAY FOR LOZ042>044-062>064.
SMALL CRAFT ADVISORY UNTIL 4 AM EST MONDAY FOR LOZ043-044.
SMALL CRAFT ADVISORY UNTIL 1 AM EST MONDAY FOR LOZ042.
&&
$$
SYNOPSIS...APFFEL
NEAR TERM...APFFEL/TMA
SHORT TERM...THOMAS
LONG TERM...CHURCH/THOMAS
AVIATION...APFFEL
MARINE...APFFEL
CLIMATE...THOMAS
AREA FORECAST DISCUSSION
NWS BUFFALO NY
715 AM EST SAT FEB 14 2015
.SYNOPSIS...
A STRENGTHENING LOW WILL BRING SNOW AND BLOWING SNOW TODAY AND
TONIGHT BEFORE THE COLDEST AIR OF THE SEASON SURGES INTO THE AREA
FOR SUNDAY AND MONDAY. DAYTIME HIGHS ON SUNDAY MAY NOT EVEN GET
ABOVE ZERO...WITH DANGEROUSLY COLD WIND CHILLS. THE COLD WEATHER
WILL CONTINUE INTO NEXT WEEK WITH MORE BELOW NORMAL TEMPERATURES.
&&
.NEAR TERM /THROUGH TONIGHT/...
THE NEXT ROUND OF WINTRY WEATHER MAY NOT BE THE HEAVIEST SNOW OF THE
SEASON...BUT THE SNOW...BLOWING SNOW...AND COLD TEMPERATURES WILL
BE A LIFE THREATENING COMBINATION. IF A VEHICLE BECOMES DISABLED
FROM THE SNOWY CONDITIONS...PASSENGERS WILL HAVE TO CONTEND WITH
DANGEROUSLY COLD WIND CHILLS.
THE EXTREME CONDITIONS WILL NOT START UNTIL A STRENGTHENING LOW
PRESSURE SYSTEM AND AN ASSOCIATED ARCTIC FRONT MOVES ACROSS THE
REGION. STRONG WINDS AND BITTERLY COLD ARCTIC AIR WILL POUR INTO
THE REGION BEHIND THIS SYSTEM. UNTIL THEN...EXPECT MAINLY LIGHT
SNOWFALL WHICH WILL INCREASE IN INTENSITY A BIT THROUGH THE
MORNING HOURS AS MOISTURE AND SURFACE CONVERGENCE INCREASE AHEAD
OF THE LOW. AT 700 AM...RADAR SHOWS A CONVERGENCE BOUNDARY
DEVELOPING ACROSS AND JUST NORTH OF BUFFALO WHICH WILL PRODUCE A
NARROW BAND OF MODERATE TO HEAVY SNOW UNTIL THE FRONT REACHES THE
AREA LATER THIS MORNING. THROUGH NOON TODAY...EXPECT 1 TO 3
INCHES OF SNOW WEST OF ROCHESTER...WITH THE GREATEST AMOUNTS
ACROSS THE BUFFALO METRO AREA. THROUGH NOON...SNOW SHOULD BE LIGHT
EAST OF ROCHESTER...GENERALLY AN INCH OR LESS.
A VIGOROUS UPPER LOW AND WEAKER SURFACE REFLECTION WILL DIVE ACROSS
THE REGION TODAY...WITH THE SURFACE LOW EVENTUALLY DEEPENING
RAPIDLY ONCE IT REACHES THE NEW ENGLAND COAST TONIGHT. WINDS WILL
INCREASE RAPIDLY WITH THE PASSAGE OF THIS LOW AND AN ASSOCIATED
FRONTAL BOUNDARY...WITH A QUICK BURST OF SNOW EXPECTED ALONG THIS.
MEANWHILE...NORTHWEST WINDS GUSTING TO 40 MPH WILL RESULT IN
BLOWING SNOW JUST BEHIND THE WIND SHIFT. A HRRR WEIGHTED
CONSENSUS OF MESOSCALE GUIDANCE BRINGS THIS INTO BUF-JHW AROUND
NOON AND ROC- ELZ AROUND 2 PM.
IN ADDITION TO LIFT WITH THE FRONT...THERE WILL BE A SMALL AREA
OF UPPER LEVEL DIFFLUENCE HEAD OF THE 500 MB LOW WHICH TRAILS THE
SURFACE LOW. GUIDANCE DIFFERS A BIT ON WHERE THIS WILL BE...WITH
A CONSENSUS FORECAST BRINGING ENHANCED SNOWFALL TO THE FINGER LAKES
REGION AND INTO OSWEGO COUNTY LATE THIS AFTERNOON AND EARLY
EVENING. THIS IS LIKELY TO BRING SNOWFALL RATES OF 1 TO 2 INCHES
AN HOUR AND PRODUCE NEAR WHITEOUT CONDITIONS SINCE IT WILL COINCIDE
WITH GUSTY SURFACE WINDS.
OUTSIDE OF THIS AREA...EXPECT A BRIEF LULL IN SNOW INTENSITY LATE
AFTERNOON AND EARLY EVENING WITH WESTERN NEW YORK UNDERNEATH THIS
CLOSED UPPER LOW. ONCE THIS UPPER LOW MOVES TO OUR EAST...THERE
WILL BE A REINFORCING SHOT OF COLD AIR AND AN UPTICK IN WINDS.
THIS SHOULD ENERGIZE LAKE EFFECT SNOWS SOUTH OF LAKE
ONTARIO...WITH AMPLE MOISTURE BENEATH THE BACK OF THE UPPER LOW
TO OFFSET THE STRONG WIND SPEEDS. THIS IS WHEN BITTERLY COLD WIND
CHILLS WILL COMBINE WITH SNOW AND BLOWING SNOW TO CREATE THE MOST
DANGEROUS CONDITIONS IN MOST AREAS. WIND CHILLS WILL PLUMMET TO 25
TO 35 BELOW LATE TONIGHT INTO SUNDAY MORNING. THE STRONGEST WINDS
AND MOST SIGNIFICANT BLOWING SNOW WILL BE JUST SOUTH OF LAKE
ONTARIO WHERE NEAR WHITEOUT CONDITIONS ARE POSSIBLE.
OVERALL...THE LATEST FORECAST HAS ONLY MADE MINOR ADJUSTMENTS TO
STORM TOTAL SNOWFALL. WITH THE STRONG WINDS AND DEEP
MOISTURE...EXPECT UPSLOPING WELL SOUTH OF THE LAKE ONTARIO SHORELINE
TO ENHANCE SNOW TOTALS A BIT. THE GREATEST AMOUNTS SHOULD BE FROM
ROCHESTER TOWARD SYRACUSE...WHERE 8 TO 14 INCHES IS FORECAST. HAVE
ALSO TWEAKED UP SNOWFALL AMOUNTS FOR BUFFALO TO ACCOUNT FOR THE
LOCALIZED CONVERGENCE BOUNDARY WHICH SETTLED ACROSS THE CITY EARLY
THIS MORNING.
&&
.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
ONE OF THE COLDEST DAYS IN DECADES WILL START THIS TIME PERIOD AS A
LOBE OF -25C TO -27C AIR AT 850 HPA REMAINS ACROSS THE REGION...WITH A
BITING NORTHWEST WIND. TO ADD TO THE EXTREME BITTERNESS...SNOW
SHOWERS WILL BE FALLING THROUGH THE DAY SOUTH OF LAKE ONTARIO.
FOR THE EXTREME TEMPERATURES...
SUNDAY NORTHWEST WINDS WILL CONTINUE TO BRING A FRESH COLD AIRMASS
ACROSS OUR REGION...WITH -25C TO -27C 850 HPA TEMPERATURES AND CAA
ADVECTION THROUGH THE DAY BRINGING -25C AIR AS LOW AS JUST A FEW
HUNDRED FEET ABOVE THE SURFACE. NAEFS MEAN TEMPERATURE AND RETURN
INTERVALS GIVE THIS 850 HPA TEMPERATURES AT LEAST A ONCE IN 10 YEAR
OCCURRENCE. GIVEN THAT TEMPERATURES OF -26C OR LOWER HAVE BEEN
MEASURED ONLY 12 TIMES IN THE MONTH OF FEBRUARY VIA BUFFALO BALLOON
SOUNDINGS (TAKEN TWICE A DAY) SINCE 1948...WE ALSO VERIFY THAT THIS
AIRMASS OCCURS ABOUT ONCE EVERY DECADE OR SO. IN FACT THE COLDEST
850 HPA TEMPERATURE MEASURED VIA BUFFALO BALLOON SOUNDING (TAKEN AT
12Z AND 00Z) IN THE MONTH OF FEBRUARY IS -27.8C BACK ON 12Z FEBRUARY
1, 1971.
THE ARCTIC AIRMASS WILL CONTINUE THE SUBFREEZING TEMPERATURES
THROUGH THE DAY ON SUNDAY...WITH DAYLIGHT HIGHS 0F TO -5F ACROSS THE LAKE
PLAINS AND DOWN TO THE NEGATIVE TEENS IN THE SOUTHERN TIER AND UPON
THE TUG HILL REGION. THESE SUBFREEZING TEMPERATURES WILL ONLY DIP
FARTHER DOWN SUNDAY NIGHT AS HIGH PRESSURE FROM THE CENTRAL GREAT
LAKES BUILDS TOWARDS THE REGION. AS SKIES CLEAR AWAY FROM THE
SOUTHERN LAKE ONTARIO SHORELINE...AND WINDS BECOME LIGHT AND
VARIABLE...SURFACE AIR TEMPERATURES OVER A FRESH AND DEEP SNOWPACK
WILL PLUMMET TO NEAR 10 BELOW ACROSS THE LAKE PLAINS...WITH
WIDESPREAD -20S IN THE SOUTHERN TIER AND PERHAPS AS LOW AS -30F
BELOW IN THE NORTH COUNTRY...INCLUDING THE WATERTOWN AIRPORT. THESE
AIR TEMPERATURES LATE SUNDAY NIGHT AND EARLY MONDAY MORNING WILL
DROP TO NEAR RECORD LEVELS FOR THE DATE OF FEBRUARY 16TH. PLEASE SEE
CLIMATE SECTION BELOW FOR VALUES.
FOR THESE SUNDAY NIGHT TEMPERATURES TO COME TO FRUITION...OUR WINDS
MUST BE LIGHT...AND A LIGHT WIND WILL ONLY NUDGE WIND CHILLS LOWER.
WIND CHILLS SUNDAY NIGHT WILL RANGE FROM -25 TO -35 BELOW...AND
ADDITIONAL HEADLINES WILL LIKELY BE NEEDED SUNDAY NIGHT FOR THESE
VERY LOW WIND CHILLS. IF WINDS WERE TO REMAIN STEADY AROUND 10
MPH...OVERNIGHT LOWS WILL LIKELY NOT BE AS LOW...THOUGH WITH THE
STRONGER WINDS WIND CHILLS VALUES WILL STILL BE IN THE -25 TO -35
BELOW RANGE.
MONDAY HIGH PRESSURE WILL ADVANCE ACROSS THE EASTERN GREAT LAKES
REGION. WARMING ALOFT WITH 850 HPA TEMPERATURES RISING TO THE
NEGATIVE TEENS WILL ALLOW FOR MANY AREAS TO RISE ABOVE 0F FOR A FEW
HOURS. THE LIGHT WINDS AND VERY LOW MIXING HEIGHTS WILL PROBABLY
KEEP MOST AREAS BELOW 5F THOUGH.
AS THIS HIGH PRESSURE SCOOTS EASTWARD MONDAY NIGHT A LIGHT SOUTHERLY
FLOW WILL DEVELOP...FIRST ACROSS WESTERN NEW YORK AND LATER ACROSS
THE NORTH COUNTRY. MOST AREAS ACROSS WNY WILL DROP BACK TO NEAR
0F...WHICH IS NOT MUCH OF A DROP CONSIDERING DAYTIME HIGHS WILL ONLY
BE IN THE LOW SINGLE DIGITS DURING THE DAYTIME. TO THE EAST WHERE
THE SOUTHERLY FLOW WILL DEVELOP LATER OVERNIGHT TEMPERATURES WILL
LIKELY DROP 5 TO PERHAPS 10 DEGREES BELOW ZERO. MID AND HIGH LEVEL
CLOUDS WILL BEGIN TO REACH THE REGION LATE OVERNIGHT...WHICH WILL
ALSO AID IN MAINTAINING LOWS NOT AS HARSH AS THE PRIOR NIGHT.
FOR THE SNOWFALL...
SUNDAY SNOW WILL CONTINUE TO FALL ACROSS THE REGION. ALOFT WEAK
ISENTROPIC UPGLIDE WILL BE PRESENTING ENOUGH LIFT TO GENERATE SNOW
SHOWERS...ACROSS THE TUG HILL EAST OF LAKE ONTARIO...AS WELL AS
AREAS SOUTH OF LAKE ONTARIO. THIS UPGLIDE...SEEN AT THE VERY LOW
255K SURFACE...WILL CONTINUE LIGHT SYNOPTIC SNOW SHOWERS INTO SUNDAY
NIGHT BEFORE THE ISENTROPIC SURFACE FLATTENS WITH THE APPROACHING
AREA OF HIGH PRESSURE.
WITHIN THIS SYNOPTIC SNOW WILL BE BANDS OF HEAVIER SNOWFALL ALONG
THE SOUTHERN LAKE ONTARIO SHORELINE. THIS CURRENT COLD AIRMASS HAS
LIKELY SHRUNK THE OPEN WATERS ON LAKE ONTARIO TO WELL LESS THAN 50
PERCENT...BUT THERE SHOULD STILL BE ENOUGH OPEN WATERS AND THERMAL
HEAT FLUX THROUGH THE THIN ICE TO CREATE LOW LEVEL INSTABILITY AND
ALLOW FOR LAKE EFFECT SNOW SHOWERS TO FALL. A LACKING SNOW CRYSTAL
GROWTH ZONE WILL LIKELY KEEP SNOWFLAKES TO THE SMALL SCALE...WITH 1
TO 2 INCHES OF ADDITIONAL SNOW SUNDAY...DROPPING TO AROUND AN INCH
OVERNIGHT AS LAKE EFFECT SNOWS BECOME THE DOMINATE CHARACTERISTIC OF
THE SNOW...AND EVEN THIS ACTIVITY WILL BE WANING THROUGH THE NIGHT
AS HIGH PRESSURE AND DRIER AIR ADVANCES TOWARDS THE REGION. BACKING
WINDS WILL BRING THESE NOW WEAKEN BANDS OF SNOW TOWARDS SOUTHEAST
AND THEN EAST OF LAKE ONTARIO MONDAY NIGHT WITH ACTIVITY LIKELY
ENDED BY THE END OF MONDAY NIGHT.
BLOWING SNOW WILL STILL BE A MAJOR CONCERN SUNDAY AS NORTHWEST WINDS
CONTINUE THE BLOWING AND DRIFTING OF SNOW ACROSS ROADWAYS. OPEN
AREAS SOUTH OF LAKE ONTARIO WILL EXPERIENCE VERY LOW VISIBILITIES AT
TIMES AS WINDS GUST 30 TO 35 MPH. THESE GUSTS WILL BE LOWER TOWARDS
THE STATE LINE...AND THE MORE FORESTED SOUTHERN TIER WILL LOWER
THE BLOWING AND DRIFTING OF SNOW.
FOR THE NORTH COUNTRY THE BEST CHANCES FOR SNOW WILL COME SUNDAY
WITH THE ISENTROPIC UPGLIDE FLOW. AFTER THIS...THE REGION WILL
LIKELY REMAIN DRY THROUGH THIS TIME PERIOD...WITH MAINLY CLEAR
SKIES.
A CLIMATE NOTE...OUR THREE MAIN CLIMATE SITES (BUFFALO, ROCHESTER,
WATERTOWN) ALL CONSIDER A CLIMATE DAY FROM MIDNIGHT TO MIDNIGHT.
THUS IF AIR TEMPERATURES ARE STILL ABOVE ZERO AT MIDNIGHT LEADING
INTO SUNDAY THESE ABOVE ZERO AIR TEMPERATURES WILL BE CONSIDERED THE
HIGH FOR THE DAY...EVEN IF THE DAYLIGHT HOURS SUNDAY REMAIN WELL
BELOW ZERO. FOR SUNDAY...IT APPEARS MUCH OF THE REGION MAY REMAIN
ABOVE ZERO AT MIDNIGHT...AND THUS THESE VALUES WILL BE THE OFFICIAL
HIGH TEMPERATURES FOR SUNDAY.
ADDITIONAL TEMPERATURE STATS WILL BE FOUND BELOW IN THE CLIMATE
SECTION.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
LATEST MEDIUM RANGE MODELS CONTINUING TO POINT TO A POTENTIAL
SOUTHERN STREAM STORM SYSTEM LIFTING OUT OF THE SOUTHERN PLAINS
TUESDAY...THEN PUSHING UP THE EASTERN SEABOARD INTO NEW ENGLAND
THROUGH WEDNESDAY. THE 00Z GFS CONTINUES TO REMAIN FARTHER WESTWARD
WITH THIS SYSTEM AND ITS TRACK THAN THE 00Z ECMWF. FOR NOW WILL
CONTINUE WITH CHANCES POPS. REGARDLESS OF THE TRACK ANOTHER ROUND OF
COLD AIR WILL FOLLOW BEHIND THE STORM SYSTEM FOR WEDNESDAY THROUGH
FRIDAY...WITH THE POTENTIAL FOR A PROLONGED LAKE EFFECT SNOW EVENT
OFF OF LAKE ONTARIO. WHILE THE NEXT ROUND OF COLD DOES NOT APPEAR AS
POTENT AS THE CURRENT ROUND FOR SUNDAY...IT WILL STILL KEEP
TEMPERATURES WELL BELOW NORMAL.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
CONDITIONS WILL GENERALLY DETERIORATE FROM W-E THIS MORNING AS LOW
PRESSURE AND AN ASSOCIATED FRONTAL BOUNDARY DIVE ACROSS THE
REGION. EXPECT WIDESPREAD IFR CONDITIONS...WITH LOCALLY LOWER
CONDITIONS WITH THE WIND SHIFT. GUSTY WINDS WILL MOVE IN BEHIND THE
FRONT WITH BLOWING SNOW ALSO LOWERING VSBY.
AFTER THIS...THERE MAY BE A BRIEF IMPROVEMENT LATE AFTERNOON AND
EARLY EVENING AS SOMEWHAT DRIER AIR MOVES IN. ANY IMPROVEMENT
SHOULD BE SHORT LIVED...WITH ANOTHER BLAST OF EVEN COLDER AIR
FORECAST TO DROP SOUTH OF LAKE ONTARIO BETWEEN 03Z AND 06Z. THIS
WILL ENHANCE LAKE EFFECT SNOW SOUTH OF THE LAKE. THIS COMBINED
WITH BLOWING SNOW WILL LOWER VSBY TO 1SM OR LESS AT BUF/ROC/IAG.
CONDITIONS WILL GRADUALLY IMPROVE LATE TONIGHT AS DRIER AIR
GRADUALLY WORKS IN. DUE TO THE VERY COLD CONDITIONS...EVEN LIGHT
SNOW SHOULD FALL AS VERY SMALL CRYSTALS WHICH WILL LOWER VSBY SIGNIFICANTLY.
OUTLOOK...
SUNDAY...IFR IN LAKE EFFECT SNOW SHOWERS SOUTHEAST OF LAKE
ONTARIO...MVFR ELSEWHERE.
MONDAY...A SLIGHT CHANCE OF MVFR/IFR IN SNOW SHOWERS SOUTHEAST OF
THE LAKES...OTHERWISE VFR.
TUESDAY...CHANCE OF MVFR/IFR IN SNOW SHOWERS.
&&
.MARINE...
WINDS WILL RAPIDLY INCREASE BEHIND A STRONG CLIPPER LOW THIS
AFTERNOON. ARCTIC AIR WILL BUILD ACROSS THE REGION BEHIND THIS AND A
30 KT NW FLOW SHOULD PRODUCE AMPLE WAVE ACTION FOR ANOTHER ROUND OF
HEAVY FREEZING SPRAY ON THE REMAINING OPEN WATERS OF LAKE ONTARIO.
HAVE KEPT WINDS IN THE STRONG SCA RANGE FOR NOW...BUT A FEW GUSTS TO
GALE ARE POSSIBLE WITH THE WIND SHIFT.
FOLLOWING COORDINATION...HAVE ISSUED GALE WARNINGS FOR LAKE
ERIE...WITH A FEW HOURS OF 35 KT WINDS EXPECTED BEHIND THE LOW LATE
THIS AFTERNOON AND EARLY EVENING. WINDS WILL BE STRONGEST ACROSS
CENTRAL AND WESTERN PORTIONS OF LAKE ERIE.
WINDS WILL DIMINISH SUNDAY NIGHT AND MONDAY AS HIGH PRESSURE BUILDS
TOWARD THE LOWER LAKES.
&&
.CLIMATE...
A FEW TEMPERATURE CLIMATE STATS BELOW...
DAILY RECORDS:
SUNDAY, FEBRUARY 15TH
MINIMUM LOW MAXIMUM
BUFFALO -16F (1943) 4F (1943)
ROCHESTER -14F (1943) 4F (1943)
WATERTOWN -30F (1987) 1F (1987)
MONDAY, FEBRUARY 16TH
MINIMUM LOW MAXIMUM
BUFFALO -8F (1904) 0F (1904)
ROCHESTER -7F (2004) -1F (1904)
WATERTOWN -24F (1963) 2F (2003)
ONE WAY TO VIEW THIS UPCOMING COLD OUTBREAK IS TO LOOK AT AVERAGE
TEMPERATURES FOR A DAY (AVERAGE OF MAXIMUM AND MINIMUM TEMPERATURE
FOR THE DAY).
LAST TIME A CLIMATE SITE HAD AN AVERAGE TEMPERATURE BELOW ZERO...
BUFFALO JANUARY 19, 1994 HIGH: -1 LOW: -10 AVERAGE: -5.5F
ROCHESTER JANUARY 14, 2004 HIGH: 4 LOW: -6 AVERAGE: -1.0F
RECENT TIMES A CLIMATE SITE HAD A MINIMUM TEMPERATURE MINUS TEN
OR LOWER...
BUFFALO JANUARY 6, 1996 LOW: -10F
JANUARY 19, 1994 LOW: -10F
JANUARY 21, 1985 LOW: -10F
JANUARY 16, 1984 LOW: -10F
JANUARY 17, 1982 LOW: -16F
ROCHESTER JANUARY 21, 2005 LOW: -10F
JANUARY 10, 2004 LOW: -12F
JANUARY 31, 1994 LOW: -10F
JANUARY 19, 1994 LOW: -11F
JANUARY 16, 1994 LOW: -17F
THOUGH THE POSSIBILITY OF A HIGH TEMPERATURE REMAINING BELOW ZERO
FOR A 24-HR DAY PERIOD IS NOW LESS LIKELY HERE ARE THE LAST TIME
CLIMATE SITES DID ACHIEVE THIS FEAT.
BUFFALO...
COLDEST HIGH TEMPERATURE ON RECORD...
-3 ON FEBRUARY 10, 1899 AND FEBRUARY 11, 1885
LAST TIME HIGH TEMPERATURE WAS BELOW ZERO...
-1 ON JANUARY 19, 1994
ROCHESTER...
COLDEST HIGH TEMPERATURE ON RECORD...
-4 ON JANUARY 17, 1982
LAST TIME HIGH TEMPERATURE WAS BELOW ZERO...
-4 ON JANUARY 17, 1982
WATERTOWN...
COLDEST HIGH TEMPERATURE ON RECORD...
-12 ON JANUARY 3, 1981
LAST TIME HIGH TEMPERATURE WAS BELOW ZERO...
-1 ON JANUARY 22, 2014
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...WINTER STORM WARNING UNTIL 6 PM EST SUNDAY FOR NYZ001>006-
010>014-019-020-085.
WINTER WEATHER ADVISORY FROM 1 PM THIS AFTERNOON TO 6 AM EST
SUNDAY FOR NYZ007-008.
WIND CHILL WARNING FROM 4 PM THIS AFTERNOON TO 10 AM EST
MONDAY FOR NYZ007-008.
WINTER WEATHER ADVISORY UNTIL 6 AM EST SUNDAY FOR NYZ021.
WIND CHILL WARNING FROM 1 PM THIS AFTERNOON TO 10 AM EST
MONDAY FOR NYZ021.
MARINE...GALE WARNING FROM 1 PM THIS AFTERNOON TO 10 PM EST THIS
EVENING FOR LEZ040-041.
HEAVY FREEZING SPRAY WARNING FROM 6 PM THIS EVENING
TO 6 AM EST MONDAY FOR LOZ042>044-062>064.
SMALL CRAFT ADVISORY UNTIL 4 AM EST MONDAY FOR LOZ043-044.
SMALL CRAFT ADVISORY UNTIL 1 AM EST MONDAY FOR LOZ042.
&&
$$
SYNOPSIS...APFFEL
NEAR TERM...APFFEL
SHORT TERM...THOMAS
LONG TERM...CHURCH/THOMAS
AVIATION...APFFEL
MARINE...APFFEL
CLIMATE...THOMAS
AREA FORECAST DISCUSSION
NWS BUFFALO NY
443 AM EST SAT FEB 14 2015
.SYNOPSIS...
A STRENGTHENING LOW WILL BRING SNOW AND BLOWING SNOW TODAY AND
TONIGHT BEFORE THE COLDEST AIR OF THE SEASON SURGES INTO THE AREA
FOR SUNDAY AND MONDAY. DAYTIME HIGHS ON SUNDAY MAY NOT EVEN GET
ABOVE ZERO...WITH DANGEROUSLY COLD WIND CHILLS. THE COLD WEATHER
WILL CONTINUE INTO NEXT WEEK WITH MORE BELOW NORMAL TEMPERATURES.
&&
.NEAR TERM /THROUGH TONIGHT/...
THE NEXT ROUND OF WINTRY WEATHER MAY NOT BE THE HEAVIEST SNOW OF THE
SEASON...BUT THE SNOW...BLOWING SNOW...AND WIND CHILLS IS A LIFE
THREATENING COMBINATION. IF A VEHICLE BECOMES DISABLED FROM THE
SNOWY CONDITIONS...PASSENGERS WILL HAVE TO CONTEND WITH
DANGEROUSLY COLD WIND CHILLS.
THE EXTREME CONDITIONS WILL NOT START UNTIL A STRENGTHENING LOW
PRESSURE SYSTEM MOVES ACROSS THE REGION...WHICH WILL BE FOLLOWED BY
STRONG WINDS AND ARCTIC AIR. THIS SYSTEM SHOULD ENTER FAR WESTERN
NEW YORK LATE THIS MORNING. UNTIL THEN...EXPECT A GENERAL LIGHT
SNOWFALL WHICH WILL INCREASE IN INTENSITY A BIT TOWARD LAKE MORNING
AS MOISTURE AND SURFACE CONVERGENCE INCREASE AHEAD OF THIS LOW.
THROUGH NOON TODAY...EXPECT 1 TO 3 INCHES OF SNOW IN THE BUFFALO
AREA AND LOCATIONS WEST WITH AN INCH OR LESS ROCHESTER EASTWARD.
A VIGOROUS UPPER LOW AND WEAKER SURFACE REFLECTION WILL DIVE ACROSS
THE REGION TODAY...WITH THE SURFACE LOW EVENTUALLY DEEPENING RAPIDLY
AS IT REACHES THE NEW ENGLAND COAST TONIGHT. WINDS WILL INCREASE
RAPIDLY WITH THE PASSAGE OF THIS LOW...AND WITH THIS EXPECT A QUICK
BURST OF SNOW. NORTHWEST WINDS GUSTING TO 40 MPH WILL RESULT IN
BLOWING SNOW. A HRRR WEIGHTED CONSENSUS OF MESOSCALE GUIDANCE BRINGS
THIS INTO BUF-JHW AROUND NOON AND ROC-ELZ AROUND 2 PM.
IN ADDITION TO LIFT WITH THE SURFACE WIND SHIFT...THERE WILL BE A
SMALL AREA OF UPPER LEVEL DIFFLUENCE WITH THE 500 MB LOW WHICH TRAILS
THE SURFACE LOW. GUIDANCE DIFFERS A BIT ON WHERE THIS WILL BE...WITH
THE FORECAST USING A CONSENSUS WHICH BRINGS ENHANCED SNOWFALL TO THE
FINGER LAKES REGION INTO OSWEGO COUNTY LATE THIS AFTERNOON AND EARLY
EVENING. THIS IS LIKELY TO LOCALLY ENHANCED SNOWFALL RATES AND
PRODUCE NEAR WHITEOUT CONDITIONS SINCE IT WILL COINCIDE WITH GUSTY
SURFACE WINDS.
OUTSIDE OF THIS AREA...EXPECT A BRIEF LULL IN SNOW INTENSITY LATE
AFTERNOON AND EARLY EVENING WITH WESTERN NEW YORK UNDERNEATH THIS
CLOSED UPPER LOW. ONCE THIS UPPER LOW MOVES TO OUR EAST...A
REINFORCING SHOT OF COLD AIR AND AN UPTICK IN WINDS. THIS SHOULD
ENERGIZE LAKE EFFECT SNOWS SOUTH OF LAKE ONTARIO...WITH AMPLE
MOISTURE BENEATH THE BACK OF THE UPPER LOW LIKELY TO OFFSET THE
STRONG WIND SPEEDS. THIS IS WHEN BITTERLY COLD WIND CHILLS WILL
COMBINE WITH SNOW AND BLOWING SNOW TO CREATE THE MOST DANGEROUS
CONDITIONS IN MOST AREAS. WIND CHILLS WILL PLUMMET TO 25 TO 35 BELOW
LATE TONIGHT INTO SUNDAY MORNING. THE STRONGEST WINDS AND MOST
SIGNIFICANT BLOWING SNOW WILL BE JUST SOUTH OF LAKE ONTARIO WHERE
NEAR WHITEOUT CONDITIONS ARE POSSIBLE.
OVERALL...THE LATEST FORECAST HAS ONLY MADE MINOR ADJUSTMENTS TO
STORM TOTAL SNOWFALL. WITH THE STRONG WINDS AND DEEP
MOISTURE...EXPECT UPSLOPING WELL SOUTH OF THE LAKE ONTARIO SHORELINE
TO ENHANCE SNOW TOTALS A BIT. THE GREATEST AMOUNTS SHOULD BE FROM
ROCHESTER TOWARD SYRACUSE...WHERE 8 TO 14 INCHES IS FORECAST.
&&
.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
ONE OF THE COLDEST DAYS IN DECADES WILL START THIS TIME PERIOD AS A
LOBE OF -25C TO -27C AIR AT 850 HPA REMAINS ACROSS THE REGION...WITH A
BITING NORTHWEST WIND. TO ADD TO THE EXTREME BITTERNESS...SNOW
SHOWERS WILL BE FALLING THROUGH THE DAY SOUTH OF LAKE ONTARIO.
FOR THE EXTREME TEMPERATURES...
SUNDAY NORTHWEST WINDS WILL CONTINUE TO BRING A FRESH COLD AIRMASS
ACROSS OUR REGION...WITH -25C TO -27C 850 HPA TEMPERATURES AND CAA
ADVECTION THROUGH THE DAY BRINGING -25C AIR AS LOW AS JUST A FEW
HUNDRED FEET ABOVE THE SURFACE. NAEFS MEAN TEMPERATURE AND RETURN
INTERVALS GIVE THIS 850 HPA TEMPERATURES AT LEAST A ONCE IN 10 YEAR
OCCURRENCE. GIVEN THAT TEMPERATURES OF -26C OR LOWER HAVE BEEN
MEASURED ONLY 12 TIMES IN THE MONTH OF FEBRUARY VIA BUFFALO BALLOON
SOUNDINGS (TAKEN TWICE A DAY) SINCE 1948...WE ALSO VERIFY THAT THIS
AIRMASS OCCURS ABOUT ONCE EVERY DECADE OR SO. IN FACT THE COLDEST
850 HPA TEMPERATURE MEASURED VIA BUFFALO BALLOON SOUNDING (TAKEN AT
12Z AND 00Z) IN THE MONTH OF FEBRUARY IS -27.8C BACK ON 12Z FEBRUARY
1, 1971.
THE ARCTIC AIRMASS WILL CONTINUE THE SUBFREEZING TEMPERATURES
THROUGH THE DAY ON SUNDAY...WITH DAYLIGHT HIGHS 0F TO -5F ACROSS THE LAKE
PLAINS AND DOWN TO THE NEGATIVE TEENS IN THE SOUTHERN TIER AND UPON
THE TUG HILL REGION. THESE SUBFREEZING TEMPERATURES WILL ONLY DIP
FARTHER DOWN SUNDAY NIGHT AS HIGH PRESSURE FROM THE CENTRAL GREAT
LAKES BUILDS TOWARDS THE REGION. AS SKIES CLEAR AWAY FROM THE
SOUTHERN LAKE ONTARIO SHORELINE...AND WINDS BECOME LIGHT AND
VARIABLE...SURFACE AIR TEMPERATURES OVER A FRESH AND DEEP SNOWPACK
WILL PLUMMET TO NEAR 10 BELOW ACROSS THE LAKE PLAINS...WITH
WIDESPREAD -20S IN THE SOUTHERN TIER AND PERHAPS AS LOW AS -30F
BELOW IN THE NORTH COUNTRY...INCLUDING THE WATERTOWN AIRPORT. THESE
AIR TEMPERATURES LATE SUNDAY NIGHT AND EARLY MONDAY MORNING WILL
DROP TO NEAR RECORD LEVELS FOR THE DATE OF FEBRUARY 16TH. PLEASE SEE
CLIMATE SECTION BELOW FOR VALUES.
FOR THESE SUNDAY NIGHT TEMPERATURES TO COME TO FRUITION...OUR WINDS
MUST BE LIGHT...AND A LIGHT WIND WILL ONLY NUDGE WIND CHILLS LOWER.
WIND CHILLS SUNDAY NIGHT WILL RANGE FROM -25 TO -35 BELOW...AND
ADDITIONAL HEADLINES WILL LIKELY BE NEEDED SUNDAY NIGHT FOR THESE
VERY LOW WIND CHILLS. IF WINDS WERE TO REMAIN STEADY AROUND 10
MPH...OVERNIGHT LOWS WILL LIKELY NOT BE AS LOW...THOUGH WITH THE
STRONGER WINDS WIND CHILLS VALUES WILL STILL BE IN THE -25 TO -35
BELOW RANGE.
MONDAY HIGH PRESSURE WILL ADVANCE ACROSS THE EASTERN GREAT LAKES
REGION. WARMING ALOFT WITH 850 HPA TEMPERATURES RISING TO THE
NEGATIVE TEENS WILL ALLOW FOR MANY AREAS TO RISE ABOVE 0F FOR A FEW
HOURS. THE LIGHT WINDS AND VERY LOW MIXING HEIGHTS WILL PROBABLY
KEEP MOST AREAS BELOW 5F THOUGH.
AS THIS HIGH PRESSURE SCOOTS EASTWARD MONDAY NIGHT A LIGHT SOUTHERLY
FLOW WILL DEVELOP...FIRST ACROSS WESTERN NEW YORK AND LATER ACROSS
THE NORTH COUNTRY. MOST AREAS ACROSS WNY WILL DROP BACK TO NEAR
0F...WHICH IS NOT MUCH OF A DROP CONSIDERING DAYTIME HIGHS WILL ONLY
BE IN THE LOW SINGLE DIGITS DURING THE DAYTIME. TO THE EAST WHERE
THE SOUTHERLY FLOW WILL DEVELOP LATER OVERNIGHT TEMPERATURES WILL
LIKELY DROP 5 TO PERHAPS 10 DEGREES BELOW ZERO. MID AND HIGH LEVEL
CLOUDS WILL BEGIN TO REACH THE REGION LATE OVERNIGHT...WHICH WILL
ALSO AID IN MAINTAINING LOWS NOT AS HARSH AS THE PRIOR NIGHT.
FOR THE SNOWFALL...
SUNDAY SNOW WILL CONTINUE TO FALL ACROSS THE REGION. ALOFT WEAK
ISENTROPIC UPGLIDE WILL BE PRESENTING ENOUGH LIFT TO GENERATE SNOW
SHOWERS...ACROSS THE TUG HILL EAST OF LAKE ONTARIO...AS WELL AS
AREAS SOUTH OF LAKE ONTARIO. THIS UPGLIDE...SEEN AT THE VERY LOW
255K SURFACE...WILL CONTINUE LIGHT SYNOPTIC SNOW SHOWERS INTO SUNDAY
NIGHT BEFORE THE ISENTROPIC SURFACE FLATTENS WITH THE APPROACHING
AREA OF HIGH PRESSURE.
WITHIN THIS SYNOPTIC SNOW WILL BE BANDS OF HEAVIER SNOWFALL ALONG
THE SOUTHERN LAKE ONTARIO SHORELINE. THIS CURRENT COLD AIRMASS HAS
LIKELY SHRUNK THE OPEN WATERS ON LAKE ONTARIO TO WELL LESS THAN 50
PERCENT...BUT THERE SHOULD STILL BE ENOUGH OPEN WATERS AND THERMAL
HEAT FLUX THROUGH THE THIN ICE TO CREATE LOW LEVEL INSTABILITY AND
ALLOW FOR LAKE EFFECT SNOW SHOWERS TO FALL. A LACKING SNOW CRYSTAL
GROWTH ZONE WILL LIKELY KEEP SNOWFLAKES TO THE SMALL SCALE...WITH 1
TO 2 INCHES OF ADDITIONAL SNOW SUNDAY...DROPPING TO AROUND AN INCH
OVERNIGHT AS LAKE EFFECT SNOWS BECOME THE DOMINATE CHARACTERISTIC OF
THE SNOW...AND EVEN THIS ACTIVITY WILL BE WANING THROUGH THE NIGHT
AS HIGH PRESSURE AND DRIER AIR ADVANCES TOWARDS THE REGION. BACKING
WINDS WILL BRING THESE NOW WEAKEN BANDS OF SNOW TOWARDS SOUTHEAST
AND THEN EAST OF LAKE ONTARIO MONDAY NIGHT WITH ACTIVITY LIKELY
ENDED BY THE END OF MONDAY NIGHT.
BLOWING SNOW WILL STILL BE A MAJOR CONCERN SUNDAY AS NORTHWEST WINDS
CONTINUE THE BLOWING AND DRIFTING OF SNOW ACROSS ROADWAYS. OPEN
AREAS SOUTH OF LAKE ONTARIO WILL EXPERIENCE VERY LOW VISIBILITIES AT
TIMES AS WINDS GUST 30 TO 35 MPH. THESE GUSTS WILL BE LOWER TOWARDS
THE STATE LINE...AND THE MORE FORESTED SOUTHERN TIER WILL LOWER
THE BLOWING AND DRIFTING OF SNOW.
FOR THE NORTH COUNTRY THE BEST CHANCES FOR SNOW WILL COME SUNDAY
WITH THE ISENTROPIC UPGLIDE FLOW. AFTER THIS...THE REGION WILL
LIKELY REMAIN DRY THROUGH THIS TIME PERIOD...WITH MAINLY CLEAR
SKIES.
A CLIMATE NOTE...OUR THREE MAIN CLIMATE SITES (BUFFALO, ROCHESTER,
WATERTOWN) ALL CONSIDER A CLIMATE DAY FROM MIDNIGHT TO MIDNIGHT.
THUS IF AIR TEMPERATURES ARE STILL ABOVE ZERO AT MIDNIGHT LEADING
INTO SUNDAY THESE ABOVE ZERO AIR TEMPERATURES WILL BE CONSIDERED THE
HIGH FOR THE DAY...EVEN IF THE DAYLIGHT HOURS SUNDAY REMAIN WELL
BELOW ZERO. FOR SUNDAY...IT APPEARS MUCH OF THE REGION MAY REMAIN
ABOVE ZERO AT MIDNIGHT...AND THUS THESE VALUES WILL BE THE OFFICIAL
HIGH TEMPERATURES FOR SUNDAY.
ADDITIONAL TEMPERATURE STATS WILL BE FOUND BELOW IN THE CLIMATE
SECTION.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
LATEST MEDIUM RANGE MODELS CONTINUING TO POINT TO A POTENTIAL
SOUTHERN STREAM STORM SYSTEM LIFTING OUT OF THE SOUTHERN PLAINS
TUESDAY...THEN PUSHING UP THE EASTERN SEABOARD INTO NEW ENGLAND
THROUGH WEDNESDAY. THE 00Z GFS CONTINUES TO REMAIN FARTHER WESTWARD
WITH THIS SYSTEM AND ITS TRACK THAN THE 00Z ECMWF. FOR NOW WILL
CONTINUE WITH CHANCES POPS. REGARDLESS OF THE TRACK ANOTHER ROUND OF
COLD AIR WILL FOLLOW BEHIND THE STORM SYSTEM FOR WEDNESDAY THROUGH
FRIDAY...WITH THE POTENTIAL FOR A PROLONGED LAKE EFFECT SNOW EVENT
OFF OF LAKE ONTARIO. WHILE THE NEXT ROUND OF COLD DOES NOT APPEAR AS
POTENT AS THE CURRENT ROUND FOR SUNDAY...IT WILL STILL KEEP
TEMPERATURES WELL BELOW NORMAL.
&&
.AVIATION /10Z SATURDAY THROUGH WEDNESDAY/...
WARM ADVECTION AND MOISTURE WILL INCREASE THIS MORNING AHEAD OF AN
APPROACHING ARCTIC FRONT...AND CONSEQUENTLY LIGHT SNOW SHOWERS WILL
ALSO DEVELOP FROM WEST TO EAST. EXPECT VARIABLE CONDITIONS THROUGH
15Z IN AND OUT OF STEADIER SNOW SHOWERS.
LATER THIS MORNING AND INTO THIS AFTERNOON LOW LEVEL CONVERGENCE AND
LIFT WILL DRAMATICALLY INCREASE WITH THE APPROACH AND PASSAGE OF THE
ARCTIC COLD FRONT...AND WILL ALSO COINCIDE WITH A PERIOD OF
IMPRESSIVE INSTABILITY. THIS WILL LIKELY LEAD TO A BRIEF BURST OF
INTENSE SNOW THAT WILL SWEEP ACROSS THE REGION...WHICH WILL BE
FURTHER COMPLICATED BY INCREASING WINDS WHICH SHOULD PRODUCE
CONSIDERABLE BLOWING AND DRIFTING SNOW. ALL OF THIS SHOULD LEAD TO A
SHORT PERIOD OF VLIFR/LIFR CONDITIONS ACCOMPANYING THE FRONTAL
PASSAGE...WITH CONDITIONS THEN IMPROVING BACK TO IFR/MVFR IN ITS
WAKE.
TONIGHT...EXPECT FAIRLY WIDESPREAD SNOW/SNOW SHOWERS TO PERSIST...
ALONG WITH IFR/LOW-END MVFR CONDITIONS.
OUTLOOK...
SUNDAY...IFR IN LAKE EFFECT SNOW SHOWERS SOUTHEAST OF LAKE
ONTARIO...MVFR ELSEWHERE.
MONDAY...A SLIGHT CHANCE OF MVFR/IFR IN SNOW SHOWERS SOUTHEAST OF
THE LAKES...OTHERWISE VFR.
TUESDAY...CHANCE OF MVFR/IFR IN SNOW SHOWERS.
&&
.MARINE...
WINDS WILL RAPIDLY INCREASE BEHIND A STRONG CLIPPER LOW THIS
AFTERNOON. ARCTIC AIR WILL BUILD ACROSS THE REGION BEHIND THIS AND A
30 KT NW FLOW SHOULD PRODUCE AMPLE WAVE ACTION FOR ANOTHER ROUND OF
HEAVY FREEZING SPRAY ON THE REMAINING OPEN WATERS OF LAKE ONTARIO.
HAVE KEPT WINDS IN THE STRONG SCA RANGE FOR NOW...BUT A FEW GUSTS TO
GALE ARE POSSIBLE WITH THE WIND SHIFT.
FOLLOWING COORDINATION...HAVE ISSUED GALE WARNINGS FOR LAKE
ERIE...WITH A FEW HOURS OF 35 KT WINDS EXPECTED BEHIND THE LOW LATE
THIS AFTERNOON AND EARLY EVENING. WINDS WILL BE STRONGEST ACROSS
CENTRAL AND WESTERN PORTIONS OF LAKE ERIE.
WINDS WILL DIMINISH SUNDAY NIGHT AND MONDAY AS HIGH PRESSURE BUILDS
TOWARD THE LOWER LAKES.
&&
.CLIMATE...
A FEW TEMPERATURE CLIMATE STATS BELOW...
DAILY RECORDS:
SUNDAY, FEBRUARY 15TH
MINIMUM LOW MAXIMUM
BUFFALO -16F (1943) 4F (1943)
ROCHESTER -14F (1943) 4F (1943)
WATERTOWN -30F (1987) 1F (1987)
MONDAY, FEBRUARY 16TH
MINIMUM LOW MAXIMUM
BUFFALO -8F (1904) 0F (1904)
ROCHESTER -7F (2004) -1F (1904)
WATERTOWN -24F (1963) 2F (2003)
ONE WAY TO VIEW THIS UPCOMING COLD OUTBREAK IS TO LOOK AT AVERAGE
TEMPERATURES FOR A DAY (AVERAGE OF MAXIMUM AND MINIMUM TEMPERATURE
FOR THE DAY).
LAST TIME A CLIMATE SITE HAD AN AVERAGE TEMPERATURE BELOW ZERO...
BUFFALO JANUARY 19, 1994 HIGH: -1 LOW: -10 AVERAGE: -5.5F
ROCHESTER JANUARY 14, 2004 HIGH: 4 LOW: -6 AVERAGE: -1.0F
RECENT TIMES A CLIMATE SITE HAD A MINIMUM TEMPERATURE MINUS TEN
OR LOWER...
BUFFALO JANUARY 6, 1996 LOW: -10F
JANUARY 19, 1994 LOW: -10F
JANUARY 21, 1985 LOW: -10F
JANUARY 16, 1984 LOW: -10F
JANUARY 17, 1982 LOW: -16F
ROCHESTER JANUARY 21, 2005 LOW: -10F
JANUARY 10, 2004 LOW: -12F
JANUARY 31, 1994 LOW: -10F
JANUARY 19, 1994 LOW: -11F
JANUARY 16, 1994 LOW: -17F
THOUGH THE POSSIBILITY OF A HIGH TEMPERATURE REMAINING BELOW ZERO
FOR A 24-HR DAY PERIOD IS NOW LESS LIKELY HERE ARE THE LAST TIME
CLIMATE SITES DID ACHIEVE THIS FEAT.
BUFFALO...
COLDEST HIGH TEMPERATURE ON RECORD...
-3 ON FEBRUARY 10, 1899 AND FEBRUARY 11, 1885
LAST TIME HIGH TEMPERATURE WAS BELOW ZERO...
-1 ON JANUARY 19, 1994
ROCHESTER...
COLDEST HIGH TEMPERATURE ON RECORD...
-4 ON JANUARY 17, 1982
LAST TIME HIGH TEMPERATURE WAS BELOW ZERO...
-4 ON JANUARY 17, 1982
WATERTOWN...
COLDEST HIGH TEMPERATURE ON RECORD...
-12 ON JANUARY 3, 1981
LAST TIME HIGH TEMPERATURE WAS BELOW ZERO...
-1 ON JANUARY 22, 2014
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...WINTER STORM WARNING UNTIL 6 PM EST SUNDAY FOR NYZ001>006-
010>014-019-020-085.
WINTER WEATHER ADVISORY FROM 1 PM THIS AFTERNOON TO 6 AM EST
SUNDAY FOR NYZ007-008.
WIND CHILL WARNING FROM 4 PM THIS AFTERNOON TO 10 AM EST
MONDAY FOR NYZ007-008.
WINTER WEATHER ADVISORY UNTIL 6 AM EST SUNDAY FOR NYZ021.
WIND CHILL WARNING FROM 1 PM THIS AFTERNOON TO 10 AM EST
MONDAY FOR NYZ021.
MARINE...GALE WARNING FROM 1 PM THIS AFTERNOON TO 10 PM EST THIS
EVENING FOR LEZ040-041.
HEAVY FREEZING SPRAY WARNING FROM 6 PM THIS EVENING
TO 6 AM EST MONDAY FOR LOZ042>044-062>064.
SMALL CRAFT ADVISORY UNTIL 4 AM EST MONDAY FOR LOZ043-044.
SMALL CRAFT ADVISORY UNTIL 1 AM EST MONDAY FOR LOZ042.
&&
$$
SYNOPSIS...APFFEL
NEAR TERM...APFFEL
SHORT TERM...THOMAS
LONG TERM...CHURCH/THOMAS
AVIATION...APFFEL/JJR
MARINE...APFFEL
CLIMATE...THOMAS
AREA FORECAST DISCUSSION
NWS BUFFALO NY
433 AM EST SAT FEB 14 2015
.SYNOPSIS...
A STRENGTHENING LOW WILL BRING SNOW AND BLOWING SNOW TODAY AND
TONIGHT BEFORE THE COLDEST AIR OF THE SEASON SURGES INTO THE AREA
FOR SUNDAY AND MONDAY. DAYTIME HIGHS ON SUNDAY MAY NOT EVEN GET
ABOVE ZERO...WITH DANGEROUSLY COLD WIND CHILLS. THE COLD WEATHER
WILL CONTINUE INTO NEXT WEEK WITH MORE BELOW NORMAL TEMPERATURES.
&&
.NEAR TERM /THROUGH TONIGHT/...
THE NEXT ROUND OF WINTRY WEATHER MAY NOT BE THE HEAVIEST SNOW OF THE
SEASON...BUT THE SNOW...BLOWING SNOW...AND WIND CHILLS IS A LIFE
THREATENING COMBINATION. IF A VEHICLE BECOMES DISABLED FROM THE
SNOWY CONDITIONS...PASSENGERS WILL HAVE TO CONTEND WITH
DANGEROUSLY COLD WIND CHILLS.
THE EXTREME CONDITIONS WILL NOT START UNTIL A STRENGTHENING LOW
PRESSURE SYSTEM MOVES ACROSS THE REGION...WHICH WILL BE FOLLOWED BY
STRONG WINDS AND ARCTIC AIR. THIS SYSTEM SHOULD ENTER FAR WESTERN
NEW YORK LATE THIS MORNING. UNTIL THEN...EXPECT A GENERAL LIGHT
SNOWFALL WHICH WILL INCREASE IN INTENSITY A BIT TOWARD LAKE MORNING
AS MOISTURE AND SURFACE CONVERGENCE INCREASE AHEAD OF THIS LOW.
THROUGH NOON TODAY...EXPECT 1 TO 3 INCHES OF SNOW IN THE BUFFALO
AREA AND LOCATIONS WEST WITH AN INCH OR LESS ROCHESTER EASTWARD.
A VIGOROUS UPPER LOW AND WEAKER SURFACE REFLECTION WILL DIVE ACROSS
THE REGION TODAY...WITH THE SURFACE LOW EVENTUALLY DEEPENING RAPIDLY
AS IT REACHES THE NEW ENGLAND COAST TONIGHT. WINDS WILL INCREASE
RAPIDLY WITH THE PASSAGE OF THIS LOW...AND WITH THIS EXPECT A QUICK
BURST OF SNOW. NORTHWEST WINDS GUSTING TO 40 MPH WILL RESULT IN
BLOWING SNOW. A HRRR WEIGHTED CONSENSUS OF MESOSCALE GUIDANCE BRINGS
THIS INTO BUF-JHW AROUND NOON AND ROC-ELZ AROUND 2 PM.
IN ADDITION TO LIFT WITH THE SURFACE WIND SHIFT...THERE WILL BE A
SMALL AREA OF UPPER LEVEL DIFFLUENCE WITH THE 500 MB LOW WHICH TRAILS
THE SURFACE LOW. GUIDANCE DIFFERS A BIT ON WHERE THIS WILL BE...WITH
THE FORECAST USING A CONSENSUS WHICH BRINGS ENHANCED SNOWFALL TO THE
FINGER LAKES REGION INTO OSWEGO COUNTY LATE THIS AFTERNOON AND EARLY
EVENING. THIS IS LIKELY TO LOCALLY ENHANCED SNOWFALL RATES AND
PRODUCE NEAR WHITEOUT CONDITIONS SINCE IT WILL COINCIDE WITH GUSTY
SURFACE WINDS.
OUTSIDE OF THIS AREA...EXPECT A BRIEF LULL IN SNOW INTENSITY LATE
AFTERNOON AND EARLY EVENING WITH WESTERN NEW YORK UNDERNEATH THIS
CLOSED UPPER LOW. ONCE THIS UPPER LOW MOVES TO OUR EAST...A
REINFORCING SHOT OF COLD AIR AND AN UPTICK IN WINDS. THIS SHOULD
ENERGIZE LAKE EFFECT SNOWS SOUTH OF LAKE ONTARIO...WITH AMPLE
MOISTURE BENEATH THE BACK OF THE UPPER LOW LIKELY TO OFFSET THE
STRONG WIND SPEEDS. THIS IS WHEN BITTERLY COLD WIND CHILLS WILL
COMBINE WITH SNOW AND BLOWING SNOW TO CREATE THE MOST DANGEROUS
CONDITIONS IN MOST AREAS. WIND CHILLS WILL PLUMMET TO 25 TO 35 BELOW
LATE TONIGHT INTO SUNDAY MORNING. THE STRONGEST WINDS AND MOST
SIGNIFICANT BLOWING SNOW WILL BE JUST SOUTH OF LAKE ONTARIO WHERE
NEAR WHITEOUT CONDITIONS ARE POSSIBLE.
OVERALL...THE LATEST FORECAST HAS ONLY MADE MINOR ADJUSTMENTS TO
STORM TOTAL SNOWFALL. WITH THE STRONG WINDS AND DEEP
MOISTURE...EXPECT UPSLOPING WELL SOUTH OF THE LAKE ONTARIO SHORELINE
TO ENHANCE SNOW TOTALS A BIT. THE GREATEST AMOUNTS SHOULD BE FROM
ROCHESTER TOWARD SYRACUSE...WHERE 8 TO 14 INCHES IS FORECAST.
&&
.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
UPDATE COMING SOON FOR SUNDAY AND SUNDAY NIGHT COMING SOON.
BY MONDAY/MONDAY NIGHT...LAKE EFFECT SNOWS WILL LINGER SOUTHEAST OF
LAKE ONTARIO...WITH HIGH TEMPERATURES GETTING INTO THE SINGLE DIGITS
ON MONDAY AND THEN BACK TO +/- ZERO BY MONDAY NIGHT.
A FEW CLIMATE STATS BELOW...
BUFFALO...
COLDEST HIGH TEMPERATURE ON RECORD...
-3 ON FEBRUARY 10, 1899 AND FEBRUARY 11, 1885
LAST TIME HIGH TEMPERATURE WAS BELOW ZERO...
-1 ON JANUARY 19, 1994
ROCHESTER...
COLDEST HIGH TEMPERATURE ON RECORD...
-4 ON JANUARY 17, 1982
LAST TIME HIGH TEMPERATURE WAS BELOW ZERO...
-4 ON JANUARY 17, 1982
WATERTOWN...
COLDEST HIGH TEMPERATURE ON RECORD...
-12 ON JANUARY 3, 1981
LAST TIME HIGH TEMPERATURE WAS BELOW ZERO...
-1 ON JANUARY 22, 2014
ADDITIONALLY...
NUMBER OF DAYS THAT REMAIN BELOW ZERO IN HISTORY
BUFFALO...12 DAYS (145 YEARS OF RECORD)
ROCHESTER...10 DAYS (145 YEARS OF RECORD)
WATERTOWN...38 DAYS (66 YEARS OF RECORD)
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
LATEST MEDIUM RANGE MODELS CONTINUING TO POINT TO A POTENTIAL
SOUTHERN STREAM STORM SYSTEM LIFTING OUT OF THE SOUTHERN PLAINS
MONDAY NIGHT AND TUESDAY...THEN PUSHING UP THE EASTERN SEABOARD INTO
NEW ENGLAND THROUGH WEDNESDAY. ANOTHER ROUND OF COLD AIR WILL FOLLOW
BEHIND THE STORM SYSTEM FOR WEDNESDAY THROUGH FRIDAY...WITH THE
POTENTIAL FOR A PROLONGED LAKE EFFECT SNOW EVENT OFF OF LAKE
ONTARIO. WHILE THE NEXT ROUND OF COLD DOESNT APPEAR AS POTENT AS THE
CURRENT ROUND FOR SUNDAY...IT WILL STILL KEEP TEMPERATURES WELL
BELOW NORMAL.
&&
.AVIATION /10Z SATURDAY THROUGH WEDNESDAY/...
WARM ADVECTION AND MOISTURE WILL INCREASE THIS MORNING AHEAD OF AN
APPROACHING ARCTIC FRONT...AND CONSEQUENTLY LIGHT SNOW SHOWERS WILL
ALSO DEVELOP FROM WEST TO EAST. EXPECT VARIABLE CONDITIONS THROUGH
15Z IN AND OUT OF STEADIER SNOW SHOWERS.
LATER THIS MORNING AND INTO THIS AFTERNOON LOW LEVEL CONVERGENCE AND
LIFT WILL DRAMATICALLY INCREASE WITH THE APPROACH AND PASSAGE OF THE
ARCTIC COLD FRONT...AND WILL ALSO COINCIDE WITH A PERIOD OF
IMPRESSIVE INSTABILITY. THIS WILL LIKELY LEAD TO A BRIEF BURST OF
INTENSE SNOW THAT WILL SWEEP ACROSS THE REGION...WHICH WILL BE
FURTHER COMPLICATED BY INCREASING WINDS WHICH SHOULD PRODUCE
CONSIDERABLE BLOWING AND DRIFTING SNOW. ALL OF THIS SHOULD LEAD TO A
SHORT PERIOD OF VLIFR/LIFR CONDITIONS ACCOMPANYING THE FRONTAL
PASSAGE...WITH CONDITIONS THEN IMPROVING BACK TO IFR/MVFR IN ITS
WAKE.
TONIGHT...EXPECT FAIRLY WIDESPREAD SNOW/SNOW SHOWERS TO PERSIST...
ALONG WITH IFR/LOW-END MVFR CONDITIONS.
OUTLOOK...
SUNDAY...IFR IN LAKE EFFECT SNOW SHOWERS SOUTHEAST OF LAKE
ONTARIO...MVFR ELSEWHERE.
MONDAY...A SLIGHT CHANCE OF MVFR/IFR IN SNOW SHOWERS SOUTHEAST OF
THE LAKES...OTHERWISE VFR.
TUESDAY...CHANCE OF MVFR/IFR IN SNOW SHOWERS.
&&
.MARINE...
WINDS WILL RAPIDLY INCREASE BEHIND A STRONG CLIPPER LOW THIS
AFTERNOON. ARCTIC AIR WILL BUILD ACROSS THE REGION BEHIND THIS AND A
30 KT NW FLOW SHOULD PRODUCE AMPLE WAVE ACTION FOR ANOTHER ROUND OF
HEAVY FREEZING SPRAY ON THE REMAINING OPEN WATERS OF LAKE ONTARIO.
HAVE KEPT WINDS IN THE STRONG SCA RANGE FOR NOW...BUT A FEW GUSTS TO
GALE ARE POSSIBLE WITH THE WIND SHIFT.
FOLLOWING COORDINATION...HAVE ISSUED GALE WARNINGS FOR LAKE
ERIE...WITH A FEW HOURS OF 35 KT WINDS EXPECTED BEHIND THE LOW LATE
THIS AFTERNOON AND EARLY EVENING. WINDS WILL BE STRONGEST ACROSS
CENTRAL AND WESTERN PORTIONS OF LAKE ERIE.
WINDS WILL DIMINISH SUNDAY NIGHT AND MONDAY AS HIGH PRESSURE BUILDS
TOWARD THE LOWER LAKES.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...WINTER STORM WARNING UNTIL 6 PM EST SUNDAY FOR NYZ001>006-
010>014-019-020-085.
WINTER WEATHER ADVISORY FROM 1 PM THIS AFTERNOON TO 6 AM EST
SUNDAY FOR NYZ007-008.
WIND CHILL WARNING FROM 4 PM THIS AFTERNOON TO 10 AM EST
MONDAY FOR NYZ007-008.
WINTER WEATHER ADVISORY UNTIL 6 AM EST SUNDAY FOR NYZ021.
WIND CHILL WARNING FROM 1 PM THIS AFTERNOON TO 10 AM EST
MONDAY FOR NYZ021.
MARINE...GALE WARNING FROM 1 PM THIS AFTERNOON TO 10 PM EST THIS
EVENING FOR LEZ040-041.
HEAVY FREEZING SPRAY WARNING FROM 6 PM THIS EVENING
TO 6 AM EST MONDAY FOR LOZ042>044-062>064.
SMALL CRAFT ADVISORY UNTIL 4 AM EST MONDAY FOR LOZ043-044.
SMALL CRAFT ADVISORY UNTIL 1 AM EST MONDAY FOR LOZ042.
&&
$$
SYNOPSIS...APFFEL
NEAR TERM...APFFEL
SHORT TERM...CHURCH
LONG TERM...CHURCH
AVIATION...APFFEL/JJR
MARINE...APFFEL
AREA FORECAST DISCUSSION
NWS RALEIGH NC
310 PM EST SAT FEB 14 2015
.SYNOPSIS...A STRONG COLD FRONT SWEEPS ACROSS NORTH CAROLINA THROUGH
THIS EVENING. ARCTIC HIGH PRESSURE THEN BUILDS SOUTHEAST OVER THE
REGION SUNDAY INTO MONDAY. A STORM SYSTEM MOVES INTO THE SOUTHEAST
UNITED STATES BY TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 310 PM SATURDAY...
THE LATEST SURFACE ANALYSIS SHOWED THE ARCTIC COLD FRONT MOVING
TOWARD THE OHIO RIVER...WITH DECENT PRESSURE FALLS ONGOING AROUND
THE DEEPENING SURFACE LOW OVER WESTERN PENNSYLVANIA AND WIND GUSTS
BEHIND THE FRONT PEAKING AT SOME LOWER 40S KNOTS IN PARTS OF CENTRAL
INDIANA AND OHIO. THERE WERE SOME GUSTS AROUND 30KT STARTING TO GET
INTO THE MOUNTAINS OF NORTH CAROLINA AND SOUTHWEST VIRGINIA. TIMING
OF THE SURFACE FRONT AND THE ONSET OF THE GUSTY WINDS MAY RESULT IN
WINDS APPROACHING WIND ADVISORY CRITERIA A LITTLE LATER...AND THE
CURRENT PLAN IS TO START THE WIND ADVISORY IN THE NORTHWEST PIEDMONT
AT 6 PM...KEEPING THE TIMING AS IS FOR THE REST OF CENTRAL NORTH
CAROLINA AND ADDING THE COUNTIES IN THE FAR SOUTHWEST PIEDMONT AS
BUFR SOUNDINGS AND HRRR WRF 10M WIND GUSTS REALLY DO NOT
DISCRIMINATE MUCH IN THE POTENTIAL WIND FOR CENTRAL NORTH CAROLINA.
THE GFS BUFR SOUNDINGS ARE CONCERNING IN TERMS OF WIND POTENTIAL
WITH SOME MIXING SUGGESTING VALUES THAT COULD APPROACH WARNING
CRITERIA REGARDING GUSTS...IN THE MID TO UPPER 40S KNOTS AT THE TOP
OF THE MIXED LAYER. THE HRRR WRF 10M WINDS ARE SIMILAR...BUT THE NAM
BUFR SOUNDINGS SHOW WINDS SOLIDLY REMAINING IN ADVISORY CRITERIA
WHICH IS SIMILAR TO THE RAP. AS NOTED IN PREVIOUS DISCUSSIONS...THE
GREATEST WIND SHOULD BE WITH AND JUST BEHIND THE FRONT THROUGH THE
EVENING AND INTO THE EARLY OVERNIGHT WITH THE STRONG PRESSURE RISES
AND THICKNESS PACKING. BY SUNRISE SUNDAY...WINDS SHOULD STILL REMAIN
GUSTY...BUT THE 925MB WINDS ARE FORECAST BY THE GFS TO FALL FROM
AROUND 50KT THIS EVENING TO 30 TO 40KT BY 12Z SUNDAY...SO THE TIMING
OF THE WIND ADVISORY TO 6 AM SEEMS REASONABLE.
THE OVERNIGHT TEMPERATURE FORECAST IS STILL CHALLENGING...WITH THE
MAV MOS TAKING KGSO NOW ALL THE WAY DOWN TO 7F FOR A LOW...WITH THE
MET MOS AT 17F AND MOST OF THE GUIDANCE NEAR 20F FOR THE REST OF
CENTRAL NORTH CAROLINA. THE BIAS-CORRECTED MOS GUIDANCE MAY HAVE THE
BEST HANDLE ON THE SITUATION...A GOOD COMPROMISE BETWEEN WHAT COULD
BE EXPECTED BASED SOLELY ON 1000-850MB THICKNESSES WHICH WOULD
STRONGLY SUGGEST SINGLE DIGITS...AND THE MAJORITY OF THE GUIDANCE
WHICH IS SEVERAL CATEGORIES HIGHER. PLANNING ON MINIMUM TEMPERATURES
IN THE LOWER TEENS NORTHWEST TO NEAR 20 FAR SOUTH.
GIVEN THE WIND AND THE FORECAST LOWS...WIND CHILL ADVISORY CRITERIA
WILL BE CLOSE IN MANY AREAS NORTH OF U.S. 64. THE ANTICIPATED
FORECAST VALUES OF WIND AND TEMPERATURE WOULD RESULT IN MINIMUM
APPARENT TEMPERATURES LATE TONIGHT JUST BELOW ZERO FROM THE
IMMEDIATE TRIAD TO NEAR HENDERSON...AND ON THE ZERO LINE FROM ABOUT
LEXINGTON TO NEAR OR JUST NORTH OF ROCKY MOUNT. IN COORDINATION WITH
ADJACENT OFFICES AND GIVEN THE GRIDDED FORECAST VALUES OF WIND CHILL
LATE WILL ISSUE A WIND CHILL ADVISORY LATE TONIGHT AND EARLY SUNDAY
MORNING FOR MUCH OF CENTRAL NORTH CAROLINA NORTH OF A LINE FROM
ABOUT KEXX TO KRWI. THIS WILL INCLUDE RANDOLPH...CHATHAM...AND WAKE
COUNTIES TO NASH AND HALIFAX NORTH. THE FORMER THREE COUNTIES COULD
LIKELY BE ON THE MARGINS OF AN ADVISORY BUT SHOULD BE CLOSE ENOUGH
IN SOME PARTS OF THEM TO INCLUDE AT THIS POINT.
EXPECT ENOUGH FORCING AS THE LEFT ENTRANCE REGION OF 140KT 300MB AND
500MB JETS...WITH THE FRONT AND STRONG MID-LEVEL VORTICITY
ADVECTION...TO HAVE ISOLATED TO SCATTERED SHOWERS ALONG THE FRONT
DESPITE PRECIPITABLE WATER VALUES ONLY RISING TO ABOUT NORMAL...OR
JUST BELOW 0.5 INCH. THE HRRR WRF DEPICTS A NARROW BAND OF ISOLATED
TO SCATTERED SHOWERS...WITH THE RELATIVELY GREATER CHANCE IN THE
INTERSTATE 85 CORRIDOR TOWARD KRWI AND KIXA CLOSER TO THE STRONGER
FORCING ALOFT AND LIFT. BUFR SOUNDINGS TOWARD KFAY AND ESPECIALLY
TOWARD KRWI SHOW THE COINCIDENCE OF LOW LEVELS COOLING AND MOISTURE
IN THE -10C OR SLIGHTLY COLDER ZONE THAT SOME OF WHATEVER
PRECIPITATION OCCURS COULD BE MIXED RAIN AND FLURRIES. ANY NON-
LIQUID SHOULD BE QUITE FLEETING WITH THE DRY AIR SURGE MOVING INTO
THE AREA AND THE PACE OF THE FRONTAL PASSAGE.
&&
.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
AS OF 310 PM SATURDAY...
THE SURFACE HIGH WILL BUILD IN RAPIDLY WITH THE GRADIENT SLOWLY
RELAXING. 925MB WINDS DIMINISH ALONG WITH 850MB WINDS DIMINISHING TO
20 TO 30KT DURING THE DAY TO 00Z MONDAY. PRECIPITABLE WATER VALUES
AT OR BELOW 0.1 INCH FROM LATE TONIGHT THROUGH SUNDAY WILL RESULT IN
A DRY AIR MASS ALTHOUGH TEMPERATURES SHOULD BE CHILLY. HIGHS SHOULD
ONLY BE FROM THE UPPER 20S FAR NORTH TO POSSIBLY THE MID 30S IN THE
FAR SOUTHWEST PIEDMONT...RESULTING IN MUCH IF NOT ALL OF THE DAY
ACROSS CENTRAL NORTH CAROLINA BELOW FREEZING. SURFACE DEW POINTS
FALL TO CLOSE TO -5F TO -10F...MAKING MINIMUM RELATIVE HUMIDITIES
FROM 15 TO 20 PERCENT. IN COORDINATION WITH THE FOREST SERVICE...
WHILE THESE MINIMUM RELATIVE HUMIDITIES ARE PRETTY LOW...THE COLD
TEMPERATURES TO START...AND THE EXPECTATION THAT AS THE TEMPERATURES
WARM SLOWLY THE WINDS GRADUALLY DIMINISH...RESULT IN MORE OF AN
INCREASED FIRE DANGER CONCERN AS OPPOSED TO RED FLAG. SHOULD THE
TEMPERATURES RISE FASTER THAN EXPECTED AND THE WIND REMAIN GUSTIER
LONGER THAN ANTICIPATED WELL INTO THE 20S KNOTS...A RED FLAG WARNING
COULD BE REQUIRED.
SUNDAY NIGHT...AS THE FLOW ALOFT BACKS...CHANNELED VORTICITY ALOFT
IS FORECAST TO MOVE INTO CENTRAL NORTH CAROLINA ALONG WITH AN
INCREASE IN UPPER-LEVEL MOISTURE. BOTH THE NAM AND GFS BUFR
SOUNDINGS PROVIDE FOR GOOD MOISTURE BY THE LATE NIGHT HOURS OVER
MUCH OF CENTRAL NORTH CAROLINA AT AND ABOVE ABOUT 700MB. THE SUB-
CLOUD LAYER IS VERY DRY AT AND AROUND 850MB...SO WHILE THERE COULD
BE VIRGA WITH EVEN SOME LIMITED LIFT...THE DRY SUB-CLOUD LAYER
SHOULD PRECLUDE ANY EVEN TRACE PRECIPITATION FROM REACHING THE
GROUND. TEMPERATURES SHOULD FALL QUICKLY SUNDAY EVENING BEFORE MORE
CLOUDS START TO MOVE IN UNDER A LIGHT WIND...LOWS IN THE TEENS TO
NEAR 20.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
AS OF 215 PM SATURDAY...
...INCREASING CONFIDENCE FOR WINTER STORM CONDITIONS LATE MONDAY
THROUGH TUESDAY...
DAYTIME MONDAY WILL SEE INCREASING CLOUDINESS AHEAD OF A LEAD SHORT
WAVE THAT`S PROGGED TO ZIP ACROSS THE STATE BETWEEN 15Z MON AND 03Z
TUE. THEN THE MAIN SYSTEM...IN THE FORM OF A SOUTHERN STREAM DRIVEN
SFC LOW WILL LIFT FROM THE DEEP SOUTH MONDAY EVENING TO SOMEWHERE
ALONG OR JUST OFF THE CAROLINA COAST DURING THE DAY TUESDAY...THEN
LIFT NE AND AWAY TUESDAY NIGHT.
IMPACTS ON MONDAY: MONDAY WILL REMAIN COLD (HIGHS ONLY IN THE LOW-
MID 30S)...AND THAT WILL SET THE STAGE FOR SNOW AS THE P-TYPE...AND
EFFICIENT ACCUMULATION POTENTIAL...WITH ANY PRECIP THAT FALLS LATE
MONDAY INTO THE EARLY MORNING HOURS TUESDAY. A BAND OF LIGHT PRECIP
IS EXPECTED TO MOVE ACROSS CENTRAL NC DURING THE LATE AFTERNOON
MONDAY THROUGH LATE MONDAY EVENING...RESULTING IN PERHAPS AN INCH OR
TWO OF SNOW ACCUMULATION MAINLY ACROSS THE WESTERN PIEDMONT AND
ALONG AND SOUTH OF HWY 64...WITH PERHAPS LIGHTER AMOUNTS ACROS OUR
NE ZONES.
THEN FOR THE MAIN SYSTEM EARLY TUESDAY MORNING THROUGH WEDNESDAY
MORNING...WE STILL HAVE FAIRLY LOW CONFIDENCE GIVEN THE ON-GOING
MODEL DIFFERENCES...ESPECIALLY NOW THAT THE 12Z ECMWF IS EVEN FASTER
AND FARTHER EAST WITH THE SFC LOW...AND MORE IMPORTANTLY MUCH
FARTHER EAST WITH THE DEEPEST MOISTURE. IF THE 12Z ECWMF WERE TO
VERIFY...WE`D BE LOOKING AT A WARNING-CRITERIA SNOW EVENT (3 OR MORE
INCHES) ACROSS MUCH OF OUR CWA...MOSTLY FALLING MONDAY NIGHT INTO
TUESDAY MORNING...WITH PERHAPS SOME FREEZING RAIN MIXING IN ACROSS
OUR SE ZONES...ALL OF WHICH ENDS BY TUESDAY AFTERNOON AS THE LOW
EXITS. THE 12Z GFS...WHICH HAS BEEN BOUNCING AROUND A LOT...HAS
SHIFTED BACK EAST A BIT WITH THE LOW POSITION AND ITS SWATH OF
HEAVIEST QPF VALUES. THE 12Z GFS SUGGESTS THE FOLLOWING:
-THE COLUMN WILL REMAIN COLDEST...THUS ALLOWING FOR AN ALL-SNOW
EVENT...ACROSS OUR TRIAD ZONES...BUT THAT`S WHERE THE LEAST QPF
IS...THUS SUGGESTING SNOW AMOUNTS BARELY REACH WARNING CRITERIA.
-A SWATH OF WARNING-CRITERIA SNOW ALONG THE HWY 64 CORRIDOR...WHICH
MAY MIX WITH OR CHANGE TO FREEZING RAIN...POTENTIALLY ADDING A LAYER
OF ICE ON TOP OF ANY SNOW THAT FALLS...DURING THE DAYLIGHT HOURS
TUESDAY...BEFORE CHANGING BACK TO SNOW TUESDAY NIGHT WITH ANOTHER
LIGHT ACCUMULATION OF SNOW BEFORE ENDING EARLY WED MORNING.
-ACROSS OUR SOUTHERN AND SOUTHEAST-MOST ZONES...A BRIEF PERIOD OF
SNOW (PERHAPS AN INCH OR SO) IN THE PREDAWN HOURS TUESDAY...THEN
CHANGING TO A PERIOD OF FREEZING RAIN DURING THE DAYTIME TUESDAY.
GFS WOULD SUGGEST THAT WARNING CRITERIA ICE ACCUMULATION (A 1/4 INCH
OR MORE) IS POSSIBLE IN THIS AREA...BUT TEMPS BY TUESDAY AFTERNOON
WILL BE CLOSE TO FREEZING..AND GIVEN THE DAYTIME FACTOR...ALL OF
WHICH COULD LIMIT ICE ACCUMS. ALSO...ACROSS THE FAR SOUTHERN PORTION
OF THIS AREA (NEAR THE SC BORDER)...TEMPS MAY WARM ENOUGH TO GO TO
ALL RAIN...WHICH WOULD GREATLY LIMIT THE ICE ACCUMS.
ONE OF THE GREATEST CHALLENGES WITH THIS FORECAST WILL BE PREDICTING
THE JUXTAPOSITION OF THE COLD-ENOUGH-FOR-SNOW AIR WITH THE HEAVY
QPF...THAT COULD RESULT IN A HEAVY SNOW SWEET SPOT SOMEWHERE IN OUR
CWA. RIGHT NOW...IT`S JUST TOO SOON TO SAY IF AND WHERE THAT WILL
HAPPEN. MORE IMPORTANTLY...WE NEED TO PAY CLOSE ATTENTION TO THE
FREEZING RAIN POTENTIAL...AS SOME OF THE GUIDANCE (SUCH AS THE
NAM...WHICH APPEARS TO BE AN OUTLIER AS IT OFTEN IS) SUGGESTS ICE
ACCUMULATION MAY BE THE BIGGER STORY HERE. STAY TUNED!
AFTER THAT STORM EXITS...LOOK FOR QUIET WEATHER FROM WEDNESDAY
THROUGH FRIDAY...ALBEIT REMAINING BITTER COLD WITH TEMPS REMAINING
BELOW FREEZING FOR A PROLONGED PERIOD DURING THE LATTER HALF OF THE
WEEK..AND POSSIBILITY FOR LOW-TEENS OR UPPER-SINGLE-DIGIT LOWS
THURSDAY AND FRIDAY MORNING. THEN THE NEXT PRECIP-MAKER APPEARS TO
ARRIVE ON SATURDAY.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
AS OF 1240 PM SATURDAY...
FOR THE 18Z VALID TAF PERIOD...PRIMARY AVIATION CONCERN WILL BE THE
WIND. AN ARCTIC FRONT WILL SWEEP THROUGH CENTRAL NORTH CAROLINA VERY
LATE THIS AFTERNOON THROUGH THE EVENING...BRINGING WITH IT A
POSSIBLE PERIOD OF LOW VFR CEILINGS AND A SHOWER OR TWO. AHEAD OF
THE FRONT SOUTHWEST WINDS GUST TO 30KT...THEN BEHIND THE FRONT...
WINDS TURN SHARPLY NORTHWEST AND INCREASE TO GUSTS AT LEAST INTO THE
UPPER 30S KNOTS...WITH A FEW HIGHER GUSTS LIKELY IN SPOTS. WIND
SPEEDS GRADUALLY DIMINISH SUNDAY.
BEYOND THE 18Z VALID TAF PERIOD...WINDS WILL CONTINUE TO DIMINISH
SUNDAY NIGHT AND BECOME LIGHT...AS HIGHER CLOUDS SPREAD INTO CENTRAL
NORTH CAROLINA AND GRADUALLY THICKEN AND LOWER OVER MOST OF THE AREA
BY MONDAY MORNING. A LOW PRESSURE SYSTEM MOVES INTO THE SOUTHEAST
STATES BY TUESDAY...AND THE EVENTUAL TRACK OF THE SYSTEM WILL HAVE
OBVIOUS IMPLICATIONS ON THE CENTRAL NORTH CAROLINA WEATHER. AVIATION
INTERESTS SHOULD MONITOR THE LATEST FORECASTS AND CONSIDER THE
EFFECTS OF WINTRY PRECIPITATION ALONG WITH SUB-VFR CONDITIONS...WITH
AT LEAST LIGHT WINTRY PRECIPITATION POSSIBLE AS EARLY AS THE DAYTIME
ON MONDAY AS THE AIR MASS MOISTENS FROM ABOVE. VFR CONDITIONS RETURN
BY WEDNESDAY AND CONTINUE THROUGH THURSDAY.
&&
.FIRE WEATHER...
AS OF 310 PM SUNDAY...
AS NOTED IN THE SHORT-TERM DISCUSSION ABOVE...FOLLOWING THE FIRE
WEATHER CONCERNS OF TODAY...SURFACE DEW POINTS FALL TO CLOSE TO -5F
TO -10F SUNDAY...MAKING MINIMUM RELATIVE HUMIDITIES FROM 15 TO 20
PERCENT. IN COORDINATION WITH THE FOREST SERVICE...WHILE THESE
MINIMUM RELATIVE HUMIDITIES ARE PRETTY LOW...THE COLD TEMPERATURES
TO START...AND THE EXPECTATION THAT AS THE TEMPERATURES WARM SLOWLY
THE WINDS GRADUALLY DIMINISH...RESULT IN MORE OF AN INCREASED FIRE
DANGER CONCERN AS OPPOSED TO RED FLAG. SHOULD THE TEMPERATURES RISE
FASTER THAN EXPECTED AND THE WIND REMAIN GUSTIER LONGER THAN
ANTICIPATED WELL INTO THE 20S KNOTS...A RED FLAG WARNING COULD BE
REQUIRED.
&&
.CLIMATE...
THE FOLLOWING ARE TEMPERATURE RECORDS FOR FEBRUARY 15 AND 16:
RECORD LOWS
GSO RDU FAY
FEBRUARY 15: 6 IN 1943 6 IN 1899 12 IN 1943
FEBRUARY 16: 8 IN 1905 11 IN 1905 17 IN 1991
RECORD LOW MAXIMUMS
GSO RDU FAY
FEBRUARY 15: 28 IN 1943 29 IN 1943 36 IN 1965
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 6 PM EST THIS EVENING FOR
NCZ007-021>025-028-038>043-073>078-083>086-088-089.
WIND ADVISORY FROM 7 PM THIS EVENING TO 6 AM EST SUNDAY FOR
NCZ008>011-024>028-040>043-073>078-083>086-088-089.
WIND ADVISORY FROM 6 PM THIS EVENING TO 6 AM EST SUNDAY FOR
NCZ007-021>023-038-039.
WIND CHILL ADVISORY FROM 4 AM TO 9 AM EST SUNDAY FOR
NCZ007>011-021>027-038>041.
&&
$$
SYNOPSIS...DJF
NEAR TERM...DJF
SHORT TERM...DJF
LONG TERM...RAH
AVIATION...DJF
FIRE WEATHER...DJF
CLIMATE...RAH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
215 PM EST SAT FEB 14 2015
.SYNOPSIS...A STRONG COLD FRONT SWEEPS ACROSS NORTH CAROLINA THROUGH
THIS EVENING. ARCTIC HIGH PRESSURE THEN BUILDS SOUTHEAST OVER THE
REGION SUNDAY INTO MONDAY. A STORM SYSTEM MOVES INTO THE SOUTHEAST
UNITED STATES BY TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1055 AM SATURDAY...
THE LATEST SURFACE ANALYSIS SHOWED THE ARCTIC COLD FRONT MOVING OUT
OF MICHIGAN AND ILLINOIS AND TOWARD THE OHIO VALLEY...WITH A BROAD
CYCLONIC FLOW AND GRADUAL PRESSURE FALLS AHEAD OF THE FRONT. ON
WATER VAPOR IMAGERY...A LEADING MID-LEVEL SHORTWAVE WAS MOVING
THROUGH CENTRAL NORTH CAROLINA WITH NUMEROUS HIGH STRATOCU OVER
PARTS OF THE AREA ALONG AND NORTH OF ABOUT U.S. 64. BEHIND THE
SHORTWAVE THERE WAS EVIDENCE OF DECREASING MOISTURE IN THE MID-
LEVELS AHEAD OF THE MORE POTENT MID-LEVEL TROUGH MOVING SOUTH OUT OF
THE GREAT LAKES. THE LATEST HRRR WRF SEEMS TO DEPICT THE TREND OF
THE CLOUD COVER FAIRLY WELL...SOME INCREASE ESPECIALLY IN THE
NORTHERN PART OF CENTRAL NORTH CAROLINA THIS MORNING WITH CLEARING
BEHIND IT...AND SOME OF THAT WAS ALREADY OCCURRING ON VISIBLE IMAGES
JUST OF THE TRIAD AS OF THIS WRITING.
NAM AND GFS BUFR SOUNDINGS...ALONG WITH RAP SOUNDINGS...INDICATE
INCREASING MIXING TAKING PLACE DURING THE AFTERNOON AS 925MB WINDS
INCREASE TO SOLIDLY 30KT BETWEEN 18Z AND 21Z. MUCH OF THE
GUIDANCE... HOWEVER...IS ALSO CONSISTENT IN A SURFACE DEW POINT
RECOVERY IN THE SOUTHWEST FLOW TODAY. RAP 1000-850MB THICKNESSES AT
12Z THIS MORNING WERE VIRTUALLY IDENTICAL TO THE SAME THICKNESS AT
KGSO...AND WITH ENOUGH SUN IN A SOUTHWEST FLOW THOSE THICKNESSES
SUPPORT HIGHS AT LEAST IN THE LOWER TO MID 50S. IT IS INTERESTING
HOW SOME OF THE MOS GUIDANCE IS SO COLD AT KRDU COMPARED TO OTHER
SITES IN CENTRAL NORTH CAROLINA...AND RUNS OF THE LAMP MOS GUIDANCE
EVEN TO 13Z FOR THERE WERE SHOWING HIGHS ONLY IN THE LOWER
40S...WITH SUBSTANTIALLY HIGHER VALUES ELSEWHERE. ANTICIPATING
ENOUGH SUN TO WARM TEMPERATURES AND CONSIDERING THE RISE IN
TEMPERATURES POSSIBLY OUTPACING THE LOW-LEVEL DEW POINT RISE...
MINIMUM RELATIVE HUMIDITIES SHOULD BE AROUND OR JUST BELOW 25
PERCENT.
MIXING HEIGHTS RISE THIS AFTERNOON WHICH SHOULD ALLOW FOR EFFICIENT
TRANSPORT OF SOME OF THE INCREASING WINDS ALOFT TO THE SURFACE.
CURRENTLY ANTICIPATING WIND GUSTS AT LEAST AROUND 30 MPH...THE
COMBINED FORECAST OF LOW RELATIVE HUMIDITIES AND THE WIND RESULTS IN
FIRE WEATHER CONDITIONS FROM THE TRIANGLE NORTH AND WEST SIMILAR TO
THOSE OVER THE SANDHILLS AND SOUTHERN COASTAL PLAIN. AS A RESULT...
OPTED TO EXPAND THE RED FLAG WARNING TO INCLUDE MUCH OF CENTRAL
NORTH CAROLINA EXCEPT FOR THE NORTHEAST PIEDMONT...WHERE MINIMUM
RELATIVE HUMIDITIES ARE FORECAST TO BE JUST A LITTLE HIGHER COMPARED
TO THE REST OF THE AREA.
AS THE FRONT APPROACHES LATE IN THE DAY...MID-LEVEL MOISTURE
INCREASES AND LANDS IN THE -10C OR SO ZONE ON BUFR AND RAP SOUNDINGS
SUCH THAT AT LEAST ISOLATED SHOWERS ARE POSSIBLE IN THE TRIAD VERY
LATE IN THE DAY...PROBABLY AFTER 5 PM. FOLLOWING THIS...SPOTTY LIGHT
SHOWERS OR SPRINKLES MAY OVERCOME AN OTHERWISE RELATIVELY DEEP ~6
THOUSAND FT SUB-CLOUD LAYER. SIMILAR TO THURSDAY...FLURRIES OR LIGHT
SNOW MAY MIX WITH THE OTHERWISE LIQUID PRECIPITATION AS IT DEPARTS
DURING THE MID-LATE EVENING.
THE BIGGER STORY WILL BE THE WIND...COLD...AND COMBINATION OF THE
TWO IN THE FORM OF LOW WIND CHILLS...WHICH WILL FOLLOW THE FRONT.
THOUGH THE SFC LAYER MAY BRIEFLY DECOUPLE AND RESULT IN A RELATIVE
MINIMUM IN WIND AROUND SUNSET...BRUTAL CAA DRIVEN BY 3-HOURLY 7-10
MB MSL PRESSURE RISES (STRONGEST OVER WESTERN AND WEST-CENTRAL VA)
WILL CAUSE THE BOUNDARY LAYER TO MIX STRONGLY AND SUPPORT...PER BUFR
FORECAST SOUNDINGS...A FEW HOUR PERIOD OF WIND GUSTS BETWEEN 35 AND
45 MPH - SLIGHTLY WEAKER OVER THE SOUTHERN PIEDMONT AND WITH A FEW
GUSTS BETWEEN 45 AND 50 MPH POSSIBLE FROM THE NORTHERN PIEDMONT TO
THE NORTHERN AND CENTRAL COASTAL PLAIN. WHILE EXTREME FOR CENTRAL NC
STANDARDS...THIS SYSTEM LOOKS EVEN MORE POTENT THAN THE ONE FROM
THU...WHICH PRODUCED MULTIPLE WIND GUSTS BETWEEN 40 AND 45 MPH OVER
THE NW PIEDMONT...SANDHILLS...AND CENTRAL COASTAL PLAIN. A WIND
ADVISORY REMAINS FOR ALL BUT THE FAR SOUTHWEST PIEDMONT...THOUGH
THOSE COUNTIES TOO MAY ULTIMATELY BE INCLUDED IN THE ADVISORY GIVEN
THE POTENTIAL FOR A BRIEF BURST OF AROUND 40 MPH WINDS IMMEDIATELY
BEHIND THE FRONT...EVEN THERE.
THE COMBINATION OF WIND...LESSENING LATE WHEN LOW TEMPERATURES IN
THE LOW-MID TEENS TO AROUND 20 DEGREES OR SO ARE EXPECTED TO BE
ACHIEVED...WILL SUPPORT LOW MINIMUM WIND CHILL VALUES MOSTLY BETWEEN
ZERO AND TEN ABOVE. HOWEVER...CONFIDENCE IN LOW TEMPERATURES TONIGHT
IS LOWER THAN WHAT WOULD BE EXPECTED FOR A SECOND PERIOD
FORECAST...SINCE MOS GUIDANCE IS A SOLID 5-10 DEGREES HIGHER THAN 2
METER TEMPERATURE OUTPUT FROM JUST ABOUT ALL AVAILABLE MODEL
GUIDANCE. SUSPECT MOS MAY BE STRUGGLING WITH THE UNUSUALLY DEEP
MIXED LAYER IN STRONG CAA OVERNIGHT...BUT WILL DEFER TO THE DAY
SHIFT FOR WHETHER OR NOT LOWS NEED TO BE ADJUSTED DOWNWARD...WHICH
WOULD THEN SUPPORT SOME WIND CHILLS IN THE FIVE BELOW ZERO TO ZERO
RANGE GENERALLY NORTH OF HWY 64...AND WHICH WOULD NECESSITATE THE
ISSUANCE OF A WIND CHILL ADVISORY FOR THOSE AREAS.
&&
.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
AS OF 350 AM SATURDAY...
ARCTIC SFC HIGH PRESSURE WILL MODIFY/WEAKEN AS IT BUILDS FROM THE
UPPER MIDWEST TOWARD THE CENTRAL APPALACHIANS THROUGH MON MORNING.
SKIES WILL BE CLEAR SUNDAY IN STRONGLY SUBSIDENT CONDITIONS BEHIND
THE POTENT UPPER TROUGH FORECAST TO CROSS OUR REGION DURING THE NEAR
TERM...FOLLOWED BY INCREASING HIGH CLOUDS SUN EVE AND ESPECIALLY
OVERNIGHT...DOWNSTREAM OF THE COMPLEX AMALGAMATION OF SHORTWAVE
TROUGHS FORECAST TO AFFECT CENTRAL NC EARLY NEXT WEEK. AFTER
CONTINUED BLUSTERY CONDITIONS EARLY SUN...NW WINDS WILL LESSEN AND
CERTAINLY BECOME LESS GUSTY BY MID-LATE AFTERNOON. WITH THE LOW
LEVEL THERMAL TROUGH OVERHEAD...ONLY UPPER 20S TO LOWER 30S ARE
ANTICIPATED FOR HIGHS. SIMILARLY VERY COLD LOWS IN THE TEENS...WITH
SOME SINGLE DIGITS PROBABLE IN THE TYPICALLY COLDER AREAS OF THE
PIEDMONT.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
AS OF 215 PM SATURDAY...
...INCREASING CONFIDENCE FOR WINTER STORM CONDITIONS LATE MONDAY
THROUGH TUESDAY...
DAYTIME MONDAY WILL SEE INCREASING CLOUDINESS AHEAD OF A LEAD SHORT
WAVE THAT`S PROGGED TO ZIP ACROSS THE STATE BETWEEN 15Z MON AND 03Z
TUE. THEN THE MAIN SYSTEM...IN THE FORM OF A SOUTHERN STREAM DRIVEN
SFC LOW WILL LIFT FROM THE DEEP SOUTH MONDAY EVENING TO SOMEWHERE
ALONG OR JUST OFF THE CAROLINA COAST DURING THE DAY TUESDAY...THEN
LIFT NE AND AWAY TUESDAY NIGHT.
IMPACTS ON MONDAY: MONDAY WILL REMAIN COLD (HIGHS ONLY IN THE LOW-
MID 30S)...AND THAT WILL SET THE STAGE FOR SNOW AS THE P-TYPE...AND
EFFICIENT ACCUMULATION POTENTIAL...WITH ANY PRECIP THAT FALLS LATE
MONDAY INTO THE EARLY MORNING HOURS TUESDAY. A BAND OF LIGHT PRECIP
IS EXPECTED TO MOVE ACROSS CENTRAL NC DURING THE LATE AFTERNOON
MONDAY THROUGH LATE MONDAY EVENING...RESULTING IN PERHAPS AN INCH OR
TWO OF SNOW ACCUMULATION MAINLY ACROSS THE WESTERN PIEDMONT AND
ALONG AND SOUTH OF HWY 64...WITH PERHAPS LIGHTER AMOUNTS ACROS OUR
NE ZONES.
THEN FOR THE MAIN SYSTEM EARLY TUESDAY MORNING THROUGH WEDNESDAY
MORNING...WE STILL HAVE FAIRLY LOW CONFIDENCE GIVEN THE ON-GOING
MODEL DIFFERENCES...ESPECIALLY NOW THAT THE 12Z ECMWF IS EVEN FASTER
AND FARTHER EAST WITH THE SFC LOW...AND MORE IMPORTANTLY MUCH
FARTHER EAST WITH THE DEEPEST MOISTURE. IF THE 12Z ECWMF WERE TO
VERIFY...WE`D BE LOOKING AT A WARNING-CRITERIA SNOW EVENT (3 OR MORE
INCHES) ACROSS MUCH OF OUR CWA...MOSTLY FALLING MONDAY NIGHT INTO
TUESDAY MORNING...WITH PERHAPS SOME FREEZING RAIN MIXING IN ACROSS
OUR SE ZONES...ALL OF WHICH ENDS BY TUESDAY AFTERNOON AS THE LOW
EXITS. THE 12Z GFS...WHICH HAS BEEN BOUNCING AROUND A LOT...HAS
SHIFTED BACK EAST A BIT WITH THE LOW POSITION AND ITS SWATH OF
HEAVIEST QPF VALUES. THE 12Z GFS SUGGESTS THE FOLLOWING:
-THE COLUMN WILL REMAIN COLDEST...THUS ALLOWING FOR AN ALL-SNOW
EVENT...ACROSS OUR TRIAD ZONES...BUT THAT`S WHERE THE LEAST QPF
IS...THUS SUGGESTING SNOW AMOUNTS BARELY REACH WARNING CRITERIA.
-A SWATH OF WARNING-CRITERIA SNOW ALONG THE HWY 64 CORRIDOR...WHICH
MAY MIX WITH OR CHANGE TO FREEZING RAIN...POTENTIALLY ADDING A LAYER
OF ICE ON TOP OF ANY SNOW THAT FALLS...DURING THE DAYLIGHT HOURS
TUESDAY...BEFORE CHANGING BACK TO SNOW TUESDAY NIGHT WITH ANOTHER
LIGHT ACCUMULATION OF SNOW BEFORE ENDING EARLY WED MORNING.
-ACROSS OUR SOUTHERN AND SOUTHEAST-MOST ZONES...A BRIEF PERIOD OF
SNOW (PERHAPS AN INCH OR SO) IN THE PREDAWN HOURS TUESDAY...THEN
CHANGING TO A PERIOD OF FREEZING RAIN DURING THE DAYTIME TUESDAY.
GFS WOULD SUGGEST THAT WARNING CRITERIA ICE ACCUMULATION (A 1/4 INCH
OR MORE) IS POSSIBLE IN THIS AREA...BUT TEMPS BY TUESDAY AFTERNOON
WILL BE CLOSE TO FREEZING..AND GIVEN THE DAYTIME FACTOR...ALL OF
WHICH COULD LIMIT ICE ACCUMS. ALSO...ACROSS THE FAR SOUTHERN PORTION
OF THIS AREA (NEAR THE SC BORDER)...TEMPS MAY WARM ENOUGH TO GO TO
ALL RAIN...WHICH WOULD GREATLY LIMIT THE ICE ACCUMS.
ONE OF THE GREATEST CHALLENGES WITH THIS FORECAST WILL BE PREDICTING
THE JUXTAPOSITION OF THE COLD-ENOUGH-FOR-SNOW AIR WITH THE HEAVY
QPF...THAT COULD RESULT IN A HEAVY SNOW SWEET SPOT SOMEWHERE IN OUR
CWA. RIGHT NOW...IT`S JUST TOO SOON TO SAY IF AND WHERE THAT WILL
HAPPEN. MORE IMPORTANTLY...WE NEED TO PAY CLOSE ATTENTION TO THE
FREEZING RAIN POTENTIAL...AS SOME OF THE GUIDANCE (SUCH AS THE
NAM...WHICH APPEARS TO BE AN OUTLIER AS IT OFTEN IS) SUGGESTS ICE
ACCUMULATION MAY BE THE BIGGER STORY HERE. STAY TUNED!
AFTER THAT STORM EXITS...LOOK FOR QUIET WEATHER FROM WEDNESDAY
THROUGH FRIDAY...ALBEIT REMAINING BITTER COLD WITH TEMPS REMAINING
BELOW FREEZING FOR A PROLONGED PERIOD DURING THE LATTER HALF OF THE
WEEK..AND POSSIBILITY FOR LOW-TEENS OR UPPER-SINGLE-DIGIT LOWS
THURSDAY AND FRIDAY MORNING. THEN THE NEXT PRECIP-MAKER APPEARS TO
ARRIVE ON SATURDAY.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
AS OF 1240 PM SATURDAY...
FOR THE 18Z VALID TAF PERIOD...PRIMARY AVIATION CONCERN WILL BE THE
WIND. AN ARCTIC FRONT WILL SWEEP THROUGH CENTRAL NORTH CAROLINA VERY
LATE THIS AFTERNOON THROUGH THE EVENING...BRINGING WITH IT A
POSSIBLE PERIOD OF LOW VFR CEILINGS AND A SHOWER OR TWO. AHEAD OF
THE FRONT SOUTHWEST WINDS GUST TO 30KT...THEN BEHIND THE FRONT...
WINDS TURN SHARPLY NORTHWEST AND INCREASE TO GUSTS AT LEAST INTO THE
UPPER 30S KNOTS...WITH A FEW HIGHER GUSTS LIKELY IN SPOTS. WIND
SPEEDS GRADUALLY DIMINISH SUNDAY.
BEYOND THE 18Z VALID TAF PERIOD...WINDS WILL CONTINUE TO DIMINISH
SUNDAY NIGHT AND BECOME LIGHT...AS HIGHER CLOUDS SPREAD INTO CENTRAL
NORTH CAROLINA AND GRADUALLY THICKEN AND LOWER OVER MOST OF THE AREA
BY MONDAY MORNING. A LOW PRESSURE SYSTEM MOVES INTO THE SOUTHEAST
STATES BY TUESDAY...AND THE EVENTUAL TRACK OF THE SYSTEM WILL HAVE
OBVIOUS IMPLICATIONS ON THE CENTRAL NORTH CAROLINA WEATHER. AVIATION
INTERESTS SHOULD MONITOR THE LATEST FORECASTS AND CONSIDER THE
EFFECTS OF WINTRY PRECIPITATION ALONG WITH SUB-VFR CONDITIONS...WITH
AT LEAST LIGHT WINTRY PRECIPITATION POSSIBLE AS EARLY AS THE DAYTIME
ON MONDAY AS THE AIR MASS MOISTENS FROM ABOVE. VFR CONDITIONS RETURN
BY WEDNESDAY AND CONTINUE THROUGH THURSDAY.
&&
.FIRE WEATHER...
AS OF 1055 AM SATURDAY...
AS NOTED IN THE NEAR-TERM DISCUSSION ABOVE...MIXING HEIGHTS RISE
THIS AFTERNOON WHICH SHOULD ALLOW FOR EFFICIENT TRANSPORT OF SOME
INCREASING WINDS ALOFT TO THE SURFACE. CURRENTLY ANTICIPATING WIND
GUSTS AT LEAST AROUND 30 MPH...THE COMBINED FORECAST OF LOW RELATIVE
HUMIDITIES AND THE WIND RESULTS IN FIRE WEATHER CONDITIONS FROM THE
TRIANGLE NORTH AND WEST SIMILAR TO THOSE OVER THE SANDHILLS AND
SOUTHERN COASTAL PLAIN. AS A RESULT...OPTED TO EXPAND THE RED FLAG
WARNING TO INCLUDE MUCH OF CENTRAL NORTH CAROLINA EXCEPT FOR THE
NORTHEAST PIEDMONT...WHERE MINIMUM RELATIVE HUMIDITIES ARE FORECAST
TO BE JUST A LITTLE HIGHER COMPARED TO THE REST OF THE AREA.
LINGERING BLUSTERY CONDITIONS ON SUNDAY...IN CONJUNCTION WITH LOW
RELATIVE HUMIDITY VALUES AROUND 20 PERCENT...MAY RESULT IN YET
ANOTHER DAY OF ELEVATED FIRE RISK...PARTICULARLY OVER THE EASTERN
HALF OF CENTRAL NC WHERE WINDS WILL BE STRONGEST (GUSTS 25 TO 30
MPH) RELATIVELY LONGEST (THROUGH EARLY-MID AFTERNOON). COLD
TEMPERATURES ONLY IN THE 20S TO LOWER 30S MAY MITIGATE THE OVERALL
THREAT...HOWEVER. WE WILL COORDINATE WITH THE NC FOREST SERVICE
LATER TODAY REGARDING FIRE RISK FOR SUNDAY.
&&
.CLIMATE...
THE FOLLOWING ARE TEMPERATURE RECORDS FOR FEBRUARY 15 AND 16:
RECORD LOWS
GSO RDU FAY
FEBRUARY 15: 6 IN 1943 6 IN 1899 12 IN 1943
FEBRUARY 16: 8 IN 1905 11 IN 1905 17 IN 1991
RECORD LOW MAXIMUMS
GSO RDU FAY
FEBRUARY 15: 28 IN 1943 29 IN 1943 36 IN 1965
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING FROM NOON TODAY TO 6 PM EST THIS EVENING FOR
NCZ007-021>025-028-038>043-073>078-083>086-088-089.
WIND ADVISORY FROM 7 PM THIS EVENING TO 6 AM EST SUNDAY FOR
NCZ008>011-024>028-040>043-074>078-085-086-088-089.
WIND ADVISORY FROM 4 PM THIS AFTERNOON TO 6 AM EST SUNDAY FOR
NCZ007-021>023-038-039.
&&
$$
SYNOPSIS...DJF
NEAR TERM...RAH
SHORT TERM...RAH
LONG TERM...RAH
AVIATION...DJF
FIRE WEATHER...RAH
CLIMATE...RAH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1241 PM EST SAT FEB 14 2015
.SYNOPSIS...A STRONG COLD FRONT SWEEPS ACROSS NORTH CAROLINA THROUGH
THIS EVENING. ARCTIC HIGH PRESSURE THEN BUILDS SOUTHEAST OVER THE
REGION SUNDAY INTO MONDAY. A STORM SYSTEM MOVES INTO THE SOUTHEAST
UNITED STATES BY TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1055 AM SATURDAY...
THE LATEST SURFACE ANALYSIS SHOWED THE ARCTIC COLD FRONT MOVING OUT
OF MICHIGAN AND ILLINOIS AND TOWARD THE OHIO VALLEY...WITH A BROAD
CYCLONIC FLOW AND GRADUAL PRESSURE FALLS AHEAD OF THE FRONT. ON
WATER VAPOR IMAGERY...A LEADING MID-LEVEL SHORTWAVE WAS MOVING
THROUGH CENTRAL NORTH CAROLINA WITH NUMEROUS HIGH STRATOCU OVER
PARTS OF THE AREA ALONG AND NORTH OF ABOUT U.S. 64. BEHIND THE
SHORTWAVE THERE WAS EVIDENCE OF DECREASING MOISTURE IN THE MID-
LEVELS AHEAD OF THE MORE POTENT MID-LEVEL TROUGH MOVING SOUTH OUT OF
THE GREAT LAKES. THE LATEST HRRR WRF SEEMS TO DEPICT THE TREND OF
THE CLOUD COVER FAIRLY WELL...SOME INCREASE ESPECIALLY IN THE
NORTHERN PART OF CENTRAL NORTH CAROLINA THIS MORNING WITH CLEARING
BEHIND IT...AND SOME OF THAT WAS ALREADY OCCURRING ON VISIBLE IMAGES
JUST OF THE TRIAD AS OF THIS WRITING.
NAM AND GFS BUFR SOUNDINGS...ALONG WITH RAP SOUNDINGS...INDICATE
INCREASING MIXING TAKING PLACE DURING THE AFTERNOON AS 925MB WINDS
INCREASE TO SOLIDLY 30KT BETWEEN 18Z AND 21Z. MUCH OF THE
GUIDANCE... HOWEVER...IS ALSO CONSISTENT IN A SURFACE DEW POINT
RECOVERY IN THE SOUTHWEST FLOW TODAY. RAP 1000-850MB THICKNESSES AT
12Z THIS MORNING WERE VIRTUALLY IDENTICAL TO THE SAME THICKNESS AT
KGSO...AND WITH ENOUGH SUN IN A SOUTHWEST FLOW THOSE THICKNESSES
SUPPORT HIGHS AT LEAST IN THE LOWER TO MID 50S. IT IS INTERESTING
HOW SOME OF THE MOS GUIDANCE IS SO COLD AT KRDU COMPARED TO OTHER
SITES IN CENTRAL NORTH CAROLINA...AND RUNS OF THE LAMP MOS GUIDANCE
EVEN TO 13Z FOR THERE WERE SHOWING HIGHS ONLY IN THE LOWER
40S...WITH SUBSTANTIALLY HIGHER VALUES ELSEWHERE. ANTICIPATING
ENOUGH SUN TO WARM TEMPERATURES AND CONSIDERING THE RISE IN
TEMPERATURES POSSIBLY OUTPACING THE LOW-LEVEL DEW POINT RISE...
MINIMUM RELATIVE HUMIDITIES SHOULD BE AROUND OR JUST BELOW 25
PERCENT.
MIXING HEIGHTS RISE THIS AFTERNOON WHICH SHOULD ALLOW FOR EFFICIENT
TRANSPORT OF SOME OF THE INCREASING WINDS ALOFT TO THE SURFACE.
CURRENTLY ANTICIPATING WIND GUSTS AT LEAST AROUND 30 MPH...THE
COMBINED FORECAST OF LOW RELATIVE HUMIDITIES AND THE WIND RESULTS IN
FIRE WEATHER CONDITIONS FROM THE TRIANGLE NORTH AND WEST SIMILAR TO
THOSE OVER THE SANDHILLS AND SOUTHERN COASTAL PLAIN. AS A RESULT...
OPTED TO EXPAND THE RED FLAG WARNING TO INCLUDE MUCH OF CENTRAL
NORTH CAROLINA EXCEPT FOR THE NORTHEAST PIEDMONT...WHERE MINIMUM
RELATIVE HUMIDITIES ARE FORECAST TO BE JUST A LITTLE HIGHER COMPARED
TO THE REST OF THE AREA.
AS THE FRONT APPROACHES LATE IN THE DAY...MID-LEVEL MOISTURE
INCREASES AND LANDS IN THE -10C OR SO ZONE ON BUFR AND RAP SOUNDINGS
SUCH THAT AT LEAST ISOLATED SHOWERS ARE POSSIBLE IN THE TRIAD VERY
LATE IN THE DAY...PROBABLY AFTER 5 PM. FOLLOWING THIS...SPOTTY LIGHT
SHOWERS OR SPRINKLES MAY OVERCOME AN OTHERWISE RELATIVELY DEEP ~6
THOUSAND FT SUB-CLOUD LAYER. SIMILAR TO THURSDAY...FLURRIES OR LIGHT
SNOW MAY MIX WITH THE OTHERWISE LIQUID PRECIPITATION AS IT DEPARTS
DURING THE MID-LATE EVENING.
THE BIGGER STORY WILL BE THE WIND...COLD...AND COMBINATION OF THE
TWO IN THE FORM OF LOW WIND CHILLS...WHICH WILL FOLLOW THE FRONT.
THOUGH THE SFC LAYER MAY BRIEFLY DECOUPLE AND RESULT IN A RELATIVE
MINIMUM IN WIND AROUND SUNSET...BRUTAL CAA DRIVEN BY 3-HOURLY 7-10
MB MSL PRESSURE RISES (STRONGEST OVER WESTERN AND WEST-CENTRAL VA)
WILL CAUSE THE BOUNDARY LAYER TO MIX STRONGLY AND SUPPORT...PER BUFR
FORECAST SOUNDINGS...A FEW HOUR PERIOD OF WIND GUSTS BETWEEN 35 AND
45 MPH - SLIGHTLY WEAKER OVER THE SOUTHERN PIEDMONT AND WITH A FEW
GUSTS BETWEEN 45 AND 50 MPH POSSIBLE FROM THE NORTHERN PIEDMONT TO
THE NORTHERN AND CENTRAL COASTAL PLAIN. WHILE EXTREME FOR CENTRAL NC
STANDARDS...THIS SYSTEM LOOKS EVEN MORE POTENT THAN THE ONE FROM
THU...WHICH PRODUCED MULTIPLE WIND GUSTS BETWEEN 40 AND 45 MPH OVER
THE NW PIEDMONT...SANDHILLS...AND CENTRAL COASTAL PLAIN. A WIND
ADVISORY REMAINS FOR ALL BUT THE FAR SOUTHWEST PIEDMONT...THOUGH
THOSE COUNTIES TOO MAY ULTIMATELY BE INCLUDED IN THE ADVISORY GIVEN
THE POTENTIAL FOR A BRIEF BURST OF AROUND 40 MPH WINDS IMMEDIATELY
BEHIND THE FRONT...EVEN THERE.
THE COMBINATION OF WIND...LESSENING LATE WHEN LOW TEMPERATURES IN
THE LOW-MID TEENS TO AROUND 20 DEGREES OR SO ARE EXPECTED TO BE
ACHIEVED...WILL SUPPORT LOW MINIMUM WIND CHILL VALUES MOSTLY BETWEEN
ZERO AND TEN ABOVE. HOWEVER...CONFIDENCE IN LOW TEMPERATURES TONIGHT
IS LOWER THAN WHAT WOULD BE EXPECTED FOR A SECOND PERIOD
FORECAST...SINCE MOS GUIDANCE IS A SOLID 5-10 DEGREES HIGHER THAN 2
METER TEMPERATURE OUTPUT FROM JUST ABOUT ALL AVAILABLE MODEL
GUIDANCE. SUSPECT MOS MAY BE STRUGGLING WITH THE UNUSUALLY DEEP
MIXED LAYER IN STRONG CAA OVERNIGHT...BUT WILL DEFER TO THE DAY
SHIFT FOR WHETHER OR NOT LOWS NEED TO BE ADJUSTED DOWNWARD...WHICH
WOULD THEN SUPPORT SOME WIND CHILLS IN THE FIVE BELOW ZERO TO ZERO
RANGE GENERALLY NORTH OF HWY 64...AND WHICH WOULD NECESSITATE THE
ISSUANCE OF A WIND CHILL ADVISORY FOR THOSE AREAS.
&&
.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
AS OF 350 AM SATURDAY...
ARCTIC SFC HIGH PRESSURE WILL MODIFY/WEAKEN AS IT BUILDS FROM THE
UPPER MIDWEST TOWARD THE CENTRAL APPALACHIANS THROUGH MON MORNING.
SKIES WILL BE CLEAR SUNDAY IN STRONGLY SUBSIDENT CONDITIONS BEHIND
THE POTENT UPPER TROUGH FORECAST TO CROSS OUR REGION DURING THE NEAR
TERM...FOLLOWED BY INCREASING HIGH CLOUDS SUN EVE AND ESPECIALLY
OVERNIGHT...DOWNSTREAM OF THE COMPLEX AMALGAMATION OF SHORTWAVE
TROUGHS FORECAST TO AFFECT CENTRAL NC EARLY NEXT WEEK. AFTER
CONTINUED BLUSTERY CONDITIONS EARLY SUN...NW WINDS WILL LESSEN AND
CERTAINLY BECOME LESS GUSTY BY MID-LATE AFTERNOON. WITH THE LOW
LEVEL THERMAL TROUGH OVERHEAD...ONLY UPPER 20S TO LOWER 30S ARE
ANTICIPATED FOR HIGHS. SIMILARLY VERY COLD LOWS IN THE TEENS...WITH
SOME SINGLE DIGITS PROBABLE IN THE TYPICALLY COLDER AREAS OF THE
PIEDMONT.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 345 AM SATURDAY...
WINTER WEATHER IS POSSIBLE EARLY NEXT WEEK...THOUGH CONFIDENCE
REMAINS LOW REGARDING POSSIBLE WINTRY PRECIP MONDAY AND TUESDAY OF
NEXT WEEK...AND THE 00Z MODEL QUITE DID NOT OFFER ANY CONVERGENCE
TOWARD A SIMILAR SOLUTION.
THE GENERAL SETUP WILL BE FOR A PAIR OF SHORTWAVES CURRENTLY OVER
OFF THE NORTHERN PACIFIC...WHICH IS A MESS ON WATER VAPOR WITH
NUMEROUS DISTURBANCES TOPPING THE UPPER RIDGE...TO DIVE SOUTHEAST
ACROSS THE ROCKIES AND THEN EAST. THE FIRST WAVE IS FORECAST TO
RACE EAST ACROSS THE OHIO VALLEY ON MONDAY...FOLLOWED BY A MORE
AMPLIFIED WAVE...WHICH ABSORBS A WEAK DISTURBANCE CURRENTLY OFF THE
CALIFORNIA BAJA...THAT CROSSES THE DEEP SOUTH ON TUESDAY. THE MAIN
QUESTIONS IN THE FORECAST ARE HOW QUICKLY PRECIP SPREADS EAST ACROSS
THE TENNESSEE VALLEY AND WHERE THE SURFACE LOW (OR MULTIPLE SURFACE
WAVES TRACK). MODELS SEEM TO BE STRUGGLING THE MOST WITH THE LEAD
WAVE...WITH THE ECMWF OUTPACING THE GFS BY 6 TO 12 HORUS RIGHT OFF
THE BAT BY BRINGING MEASURABLE PRECIP ACROSS ALL OF CENTRAL NC BY
MONDAY AFTERNOON/EVENING. DRIVEN MAINLY BY RIGHT JET ENTRANCE UPPER
DIVERGENCE...THE ECMWF LOOKS TOO WET/FAST/NORTH AND IS NOT SUPPORTED
BY THE NAM OR GFS FOR MONDAY. WILL MAINTAIN A SLIGHT CHANCE OF SNOW
ACROSS THE WESTERN/SOUTHERN PIEDMONT MONDAY AFTERNOON AND EARLY
EVENING TO ACCOUNT FOR THIS POSSIBILITY. EXPECT HIGHS MONDAY TO BE
LOWER THAN GUIDANCE GIVEN THAT THERE SHOULD BE WIDESPREAD MID/HIGH
CLOUDS....EVEN WITHOUT PRECIP...AFTER A VERY COLD START AND GUIDANCE
IS CLOSE TO FULL SUN THICKNESS VALUES. HIGHS 30-35.
THE MORE IMPACTFUL WEATHER POTENTIAL COMES MONDAY NIGHT AND TUESDAY
AS STRONGER HEIGHT FALLS SPREAD ACROSS THE SOUTHEAST AHEAD OF THE
SECOND AND MORE AMPLIFIED SHORTWAVE. A SURFACE LOW IS EXPECTED
DEVELOP FROM THE GULF COAST TOWARD THE CAROLINA COAST DURING THE DAY
TUESDAY...THOUGH THE LOW TRACK IS STILL VERY MUCH IN QUESTION. THE
GFS IS SEVERAL MB LOWER AND FURTHER WEST THAN THE WEAKER/OFFSHORE
ECMWF. AS USUAL...THIS WILL PLAY A MAJOR ROLE IN EXACTLY WHERE A
TRANSITION ZONE (LIKELY SHARP) BETWEEN MORE FROZEN AND MORE LIQUID
PRECIP WOULD END UP. BASED ON THE PRECEDING AIRMASS MONDAY/MONDAY
NIGHT AND PTYPE NOMOGRAMS...CURRENTLY FEEL THAT PRECIP WILL STAND A
GOOD CHANCE OF BEING ALL SNOW AT ONSET MONDAY NIGHT/EARLY TUESDAY
AND THAT A LARGER-THAN-TYPICAL AREA COULD SEE SEVERAL HOURS OF A
LEAST A WINTRY MIX TUESDAY. SURFACE TEMPS WOULD ALSO BE FAVORABLE
FOR ACCUMULATION. THUS...WHILE CONFIDENCE IN THE DETAILS OF THE
FORECAST IS LOW...CONFIDENCE IS MEDIUM AND SLOWLY GROWING THAT THIS
SHOULD BE AT LEAST AN ADVISORY EVENT.
GIVEN THAT MODELS STILL AREN`T INITIALIZING WITH MUCH INFORMATION ON
THE MAIN PLAYERS IN THIS SYSTEM AND ARE STILL VERY DIFFERENT...THE
BEST COURSE OF ACTION WITH THIS FORECAST PACKAGE MAY BE TO JUST
CONTINUE THE ADVERTISED PTYPES.
THE SURFACE LOW WILL LIFT OFF TO THE NORTHEAST WEDNESDAY...WITH
PRECIP ENDING (POSSIBLY AS SNOW) BY WEDNESDAY AFTERNOON. ANOTHER
BLAST OF ARCTIC AIR IS EXPECTED ON ITS HEELS FOR LATE WEEK AS THE
TRAIN OF SHORTWAVES INTO THE EAST COAST TROUGH CONTINUES. MODELS
ARE TRENDING COLDER FOR THURS THROUGH SATURDAY...WITH ANOTHER ROUND
OF LOWS IN THE TEENS OR SINGLE DIGITS AND HIGHS IN THE 30S POSSIBLE.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
AS OF 1240 PM SATURDAY...
FOR THE 18Z VALID TAF PERIOD...PRIMARY AVIATION CONCERN WILL BE THE
WIND. AN ARCTIC FRONT WILL SWEEP THROUGH CENTRAL NORTH CAROLINA VERY
LATE THIS AFTERNOON THROUGH THE EVENING...BRINGING WITH IT A
POSSIBLE PERIOD OF LOW VFR CEILINGS AND A SHOWER OR TWO. AHEAD OF
THE FRONT SOUTHWEST WINDS GUST TO 30KT...THEN BEHIND THE FRONT...
WINDS TURN SHARPLY NORTHWEST AND INCREASE TO GUSTS AT LEAST INTO THE
UPPER 30S KNOTS...WITH A FEW HIGHER GUSTS LIKELY IN SPOTS. WIND
SPEEDS GRADUALLY DIMINISH SUNDAY.
BEYOND THE 18Z VALID TAF PERIOD...WINDS WILL CONTINUE TO DIMINISH
SUNDAY NIGHT AND BECOME LIGHT...AS HIGHER CLOUDS SPREAD INTO CENTRAL
NORTH CAROLINA AND GRADUALLY THICKEN AND LOWER OVER MOST OF THE AREA
BY MONDAY MORNING. A LOW PRESSURE SYSTEM MOVES INTO THE SOUTHEAST
STATES BY TUESDAY...AND THE EVENTUAL TRACK OF THE SYSTEM WILL HAVE
OBVIOUS IMPLICATIONS ON THE CENTRAL NORTH CAROLINA WEATHER. AVIATION
INTERESTS SHOULD MONITOR THE LATEST FORECASTS AND CONSIDER THE
EFFECTS OF WINTRY PRECIPITATION ALONG WITH SUB-VFR CONDITIONS...WITH
AT LEAST LIGHT WINTRY PRECIPITATION POSSIBLE AS EARLY AS THE DAYTIME
ON MONDAY AS THE AIR MASS MOISTENS FROM ABOVE. VFR CONDITIONS RETURN
BY WEDNESDAY AND CONTINUE THROUGH THURSDAY.
&&
.FIRE WEATHER...
AS OF 1055 AM SATURDAY...
AS NOTED IN THE NEAR-TERM DISCUSSION ABOVE...MIXING HEIGHTS RISE
THIS AFTERNOON WHICH SHOULD ALLOW FOR EFFICIENT TRANSPORT OF SOME
INCREASING WINDS ALOFT TO THE SURFACE. CURRENTLY ANTICIPATING WIND
GUSTS AT LEAST AROUND 30 MPH...THE COMBINED FORECAST OF LOW RELATIVE
HUMIDITIES AND THE WIND RESULTS IN FIRE WEATHER CONDITIONS FROM THE
TRIANGLE NORTH AND WEST SIMILAR TO THOSE OVER THE SANDHILLS AND
SOUTHERN COASTAL PLAIN. AS A RESULT...OPTED TO EXPAND THE RED FLAG
WARNING TO INCLUDE MUCH OF CENTRAL NORTH CAROLINA EXCEPT FOR THE
NORTHEAST PIEDMONT...WHERE MINIMUM RELATIVE HUMIDITIES ARE FORECAST
TO BE JUST A LITTLE HIGHER COMPARED TO THE REST OF THE AREA.
LINGERING BLUSTERY CONDITIONS ON SUNDAY...IN CONJUNCTION WITH LOW
RELATIVE HUMIDITY VALUES AROUND 20 PERCENT...MAY RESULT IN YET
ANOTHER DAY OF ELEVATED FIRE RISK...PARTICULARLY OVER THE EASTERN
HALF OF CENTRAL NC WHERE WINDS WILL BE STRONGEST (GUSTS 25 TO 30
MPH) RELATIVELY LONGEST (THROUGH EARLY-MID AFTERNOON). COLD
TEMPERATURES ONLY IN THE 20S TO LOWER 30S MAY MITIGATE THE OVERALL
THREAT...HOWEVER. WE WILL COORDINATE WITH THE NC FOREST SERVICE
LATER TODAY REGARDING FIRE RISK FOR SUNDAY.
&&
.CLIMATE...
THE FOLLOWING ARE TEMPERATURE RECORDS FOR FEBRUARY 15 AND 16:
RECORD LOWS
GSO RDU FAY
FEBRUARY 15: 6 IN 1943 6 IN 1899 12 IN 1943
FEBRUARY 16: 8 IN 1905 11 IN 1905 17 IN 1991
RECORD LOW MAXIMUMS
GSO RDU FAY
FEBRUARY 15: 28 IN 1943 29 IN 1943 36 IN 1965
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING FROM NOON TODAY TO 6 PM EST THIS EVENING FOR
NCZ007-021>025-028-038>043-073>078-083>086-088-089.
WIND ADVISORY FROM 7 PM THIS EVENING TO 6 AM EST SUNDAY FOR
NCZ008>011-024>028-040>043-074>078-085-086-088-089.
WIND ADVISORY FROM 4 PM THIS AFTERNOON TO 6 AM EST SUNDAY FOR
NCZ007-021>023-038-039.
&&
$$
SYNOPSIS...DJF
NEAR TERM...RAH
SHORT TERM...RAH
LONG TERM...SMITH
AVIATION...DJF
FIRE WEATHER...RAH
CLIMATE...RAH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1055 AM EST SAT FEB 14 2015
.SYNOPSIS...HIGH PRESSURE ALONG THE SOUTH ATLANTIC COAST MOVES
OFFSHORE THIS AFTERNOON...IN ADVANCE OF AN ARCTIC COLD FRONT THAT
WILL BLAST ACROSS OUR REGION THIS EVENING. ARCTIC HIGH PRESSURE WILL
FOLLOW AND BUILD ACROSS THE MIDDLE ATLANTIC STATES TONIGHT THROUGH
MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1055 AM SATURDAY...
THE LATEST SURFACE ANALYSIS SHOWED THE ARCTIC COLD FRONT MOVING OUT
OF MICHIGAN AND ILLINOIS AND TOWARD THE OHIO VALLEY...WITH A BROAD
CYCLONIC FLOW AND GRADUAL PRESSURE FALLS AHEAD OF THE FRONT. ON
WATER VAPOR IMAGERY...A LEADING MID-LEVEL SHORTWAVE WAS MOVING
THROUGH CENTRAL NORTH CAROLINA WITH NUMEROUS HIGH STRATOCU OVER
PARTS OF THE AREA ALONG AND NORTH OF ABOUT U.S. 64. BEHIND THE
SHORTWAVE THERE WAS EVIDENCE OF DECREASING MOISTURE IN THE MID-
LEVELS AHEAD OF THE MORE POTENT MID-LEVEL TROUGH MOVING SOUTH OUT OF
THE GREAT LAKES. THE LATEST HRRR WRF SEEMS TO DEPICT THE TREND OF
THE CLOUD COVER FAIRLY WELL...SOME INCREASE ESPECIALLY IN THE
NORTHERN PART OF CENTRAL NORTH CAROLINA THIS MORNING WITH CLEARING
BEHIND IT...AND SOME OF THAT WAS ALREADY OCCURRING ON VISIBLE IMAGES
JUST OF THE TRIAD AS OF THIS WRITING.
NAM AND GFS BUFR SOUNDINGS...ALONG WITH RAP SOUNDINGS...INDICATE
INCREASING MIXING TAKING PLACE DURING THE AFTERNOON AS 925MB WINDS
INCREASE TO SOLIDLY 30KT BETWEEN 18Z AND 21Z. MUCH OF THE
GUIDANCE... HOWEVER...IS ALSO CONSISTENT IN A SURFACE DEW POINT
RECOVERY IN THE SOUTHWEST FLOW TODAY. RAP 1000-850MB THICKNESSES AT
12Z THIS MORNING WERE VIRTUALLY IDENTICAL TO THE SAME THICKNESS AT
KGSO...AND WITH ENOUGH SUN IN A SOUTHWEST FLOW THOSE THICKNESSES
SUPPORT HIGHS AT LEAST IN THE LOWER TO MID 50S. IT IS INTERESTING
HOW SOME OF THE MOS GUIDANCE IS SO COLD AT KRDU COMPARED TO OTHER
SITES IN CENTRAL NORTH CAROLINA...AND RUNS OF THE LAMP MOS GUIDANCE
EVEN TO 13Z FOR THERE WERE SHOWING HIGHS ONLY IN THE LOWER
40S...WITH SUBSTANTIALLY HIGHER VALUES ELSEWHERE. ANTICIPATING
ENOUGH SUN TO WARM TEMPERATURES AND CONSIDERING THE RISE IN
TEMPERATURES POSSIBLY OUTPACING THE LOW-LEVEL DEW POINT RISE...
MINIMUM RELATIVE HUMIDITIES SHOULD BE AROUND OR JUST BELOW 25
PERCENT.
MIXING HEIGHTS RISE THIS AFTERNOON WHICH SHOULD ALLOW FOR EFFICIENT
TRANSPORT OF SOME OF THE INCREASING WINDS ALOFT TO THE SURFACE.
CURRENTLY ANTICIPATING WIND GUSTS AT LEAST AROUND 30 MPH...THE
COMBINED FORECAST OF LOW RELATIVE HUMIDITIES AND THE WIND RESULTS IN
FIRE WEATHER CONDITIONS FROM THE TRIANGLE NORTH AND WEST SIMILAR TO
THOSE OVER THE SANDHILLS AND SOUTHERN COASTAL PLAIN. AS A RESULT...
OPTED TO EXPAND THE RED FLAG WARNING TO INCLUDE MUCH OF CENTRAL
NORTH CAROLINA EXCEPT FOR THE NORTHEAST PIEDMONT...WHERE MINIMUM
RELATIVE HUMIDITIES ARE FORECAST TO BE JUST A LITTLE HIGHER COMPARED
TO THE REST OF THE AREA.
AS THE FRONT APPROACHES LATE IN THE DAY...MID-LEVEL MOISTURE
INCREASES AND LANDS IN THE -10C OR SO ZONE ON BUFR AND RAP SOUNDINGS
SUCH THAT AT LEAST ISOLATED SHOWERS ARE POSSIBLE IN THE TRIAD VERY
LATE IN THE DAY...PROBABLY AFTER 5 PM. FOLLOWING THIS...SPOTTY LIGHT
SHOWERS OR SPRINKLES MAY OVERCOME AN OTHERWISE RELATIVELY DEEP ~6
THOUSAND FT SUB-CLOUD LAYER. SIMILAR TO THURSDAY...FLURRIES OR LIGHT
SNOW MAY MIX WITH THE OTHERWISE LIQUID PRECIPITATION AS IT DEPARTS
DURING THE MID-LATE EVENING.
THE BIGGER STORY WILL BE THE WIND...COLD...AND COMBINATION OF THE
TWO IN THE FORM OF LOW WIND CHILLS...WHICH WILL FOLLOW THE FRONT.
THOUGH THE SFC LAYER MAY BRIEFLY DECOUPLE AND RESULT IN A RELATIVE
MINIMUM IN WIND AROUND SUNSET...BRUTAL CAA DRIVEN BY 3-HOURLY 7-10
MB MSL PRESSURE RISES (STRONGEST OVER WESTERN AND WEST-CENTRAL VA)
WILL CAUSE THE BOUNDARY LAYER TO MIX STRONGLY AND SUPPORT...PER BUFR
FORECAST SOUNDINGS...A FEW HOUR PERIOD OF WIND GUSTS BETWEEN 35 AND
45 MPH - SLIGHTLY WEAKER OVER THE SOUTHERN PIEDMONT AND WITH A FEW
GUSTS BETWEEN 45 AND 50 MPH POSSIBLE FROM THE NORTHERN PIEDMONT TO
THE NORTHERN AND CENTRAL COASTAL PLAIN. WHILE EXTREME FOR CENTRAL NC
STANDARDS...THIS SYSTEM LOOKS EVEN MORE POTENT THAN THE ONE FROM
THU...WHICH PRODUCED MULTIPLE WIND GUSTS BETWEEN 40 AND 45 MPH OVER
THE NW PIEDMONT...SANDHILLS...AND CENTRAL COASTAL PLAIN. A WIND
ADVISORY REMAINS FOR ALL BUT THE FAR SOUTHWEST PIEDMONT...THOUGH
THOSE COUNTIES TOO MAY ULTIMATELY BE INCLUDED IN THE ADVISORY GIVEN
THE POTENTIAL FOR A BRIEF BURST OF AROUND 40 MPH WINDS IMMEDIATELY
BEHIND THE FRONT...EVEN THERE.
THE COMBINATION OF WIND...LESSENING LATE WHEN LOW TEMPERATURES IN
THE LOW-MID TEENS TO AROUND 20 DEGREES OR SO ARE EXPECTED TO BE
ACHIEVED...WILL SUPPORT LOW MINIMUM WIND CHILL VALUES MOSTLY BETWEEN
ZERO AND TEN ABOVE. HOWEVER...CONFIDENCE IN LOW TEMPERATURES TONIGHT
IS LOWER THAN WHAT WOULD BE EXPECTED FOR A SECOND PERIOD
FORECAST...SINCE MOS GUIDANCE IS A SOLID 5-10 DEGREES HIGHER THAN 2
METER TEMPERATURE OUTPUT FROM JUST ABOUT ALL AVAILABLE MODEL
GUIDANCE. SUSPECT MOS MAY BE STRUGGLING WITH THE UNUSUALLY DEEP
MIXED LAYER IN STRONG CAA OVERNIGHT...BUT WILL DEFER TO THE DAY
SHIFT FOR WHETHER OR NOT LOWS NEED TO BE ADJUSTED DOWNWARD...WHICH
WOULD THEN SUPPORT SOME WIND CHILLS IN THE FIVE BELOW ZERO TO ZERO
RANGE GENERALLY NORTH OF HWY 64...AND WHICH WOULD NECESSITATE THE
ISSUANCE OF A WIND CHILL ADVISORY FOR THOSE AREAS.
&&
.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
AS OF 350 AM SATURDAY...
ARCTIC SFC HIGH PRESSURE WILL MODIFY/WEAKEN AS IT BUILDS FROM THE
UPPER MIDWEST TOWARD THE CENTRAL APPALACHIANS THROUGH MON MORNING.
SKIES WILL BE CLEAR SUNDAY IN STRONGLY SUBSIDENT CONDITIONS BEHIND
THE POTENT UPPER TROUGH FORECAST TO CROSS OUR REGION DURING THE NEAR
TERM...FOLLOWED BY INCREASING HIGH CLOUDS SUN EVE AND ESPECIALLY
OVERNIGHT...DOWNSTREAM OF THE COMPLEX AMALGAMATION OF SHORTWAVE
TROUGHS FORECAST TO AFFECT CENTRAL NC EARLY NEXT WEEK. AFTER
CONTINUED BLUSTERY CONDITIONS EARLY SUN...NW WINDS WILL LESSEN AND
CERTAINLY BECOME LESS GUSTY BY MID-LATE AFTERNOON. WITH THE LOW
LEVEL THERMAL TROUGH OVERHEAD...ONLY UPPER 20S TO LOWER 30S ARE
ANTICIPATED FOR HIGHS. SIMILARLY VERY COLD LOWS IN THE TEENS...WITH
SOME SINGLE DIGITS PROBABLE IN THE TYPICALLY COLDER AREAS OF THE
PIEDMONT.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 345 AM SATURDAY...
WINTER WEATHER IS POSSIBLE EARLY NEXT WEEK...THOUGH CONFIDENCE
REMAINS LOW REGARDING POSSIBLE WINTRY PRECIP MONDAY AND TUESDAY OF
NEXT WEEK...AND THE 00Z MODEL QUITE DID NOT OFFER ANY CONVERGENCE
TOWARD A SIMILAR SOLUTION.
THE GENERAL SETUP WILL BE FOR A PAIR OF SHORTWAVES CURRENTLY OVER
OFF THE NORTHERN PACIFIC...WHICH IS A MESS ON WATER VAPOR WITH
NUMEROUS DISTURBANCES TOPPING THE UPPER RIDGE...TO DIVE SOUTHEAST
ACROSS THE ROCKIES AND THEN EAST. THE FIRST WAVE IS FORECAST TO
RACE EAST ACROSS THE OHIO VALLEY ON MONDAY...FOLLOWED BY A MORE
AMPLIFIED WAVE...WHICH ABSORBS A WEAK DISTURBANCE CURRENTLY OFF THE
CALIFORNIA BAJA...THAT CROSSES THE DEEP SOUTH ON TUESDAY. THE MAIN
QUESTIONS IN THE FORECAST ARE HOW QUICKLY PRECIP SPREADS EAST ACROSS
THE TENNESSEE VALLEY AND WHERE THE SURFACE LOW (OR MULTIPLE SURFACE
WAVES TRACK). MODELS SEEM TO BE STRUGGLING THE MOST WITH THE LEAD
WAVE...WITH THE ECMWF OUTPACING THE GFS BY 6 TO 12 HORUS RIGHT OFF
THE BAT BY BRINGING MEASURABLE PRECIP ACROSS ALL OF CENTRAL NC BY
MONDAY AFTERNOON/EVENING. DRIVEN MAINLY BY RIGHT JET ENTRANCE UPPER
DIVERGENCE...THE ECMWF LOOKS TOO WET/FAST/NORTH AND IS NOT SUPPORTED
BY THE NAM OR GFS FOR MONDAY. WILL MAINTAIN A SLIGHT CHANCE OF SNOW
ACROSS THE WESTERN/SOUTHERN PIEDMONT MONDAY AFTERNOON AND EARLY
EVENING TO ACCOUNT FOR THIS POSSIBILITY. EXPECT HIGHS MONDAY TO BE
LOWER THAN GUIDANCE GIVEN THAT THERE SHOULD BE WIDESPREAD MID/HIGH
CLOUDS....EVEN WITHOUT PRECIP...AFTER A VERY COLD START AND GUIDANCE
IS CLOSE TO FULL SUN THICKNESS VALUES. HIGHS 30-35.
THE MORE IMPACTFUL WEATHER POTENTIAL COMES MONDAY NIGHT AND TUESDAY
AS STRONGER HEIGHT FALLS SPREAD ACROSS THE SOUTHEAST AHEAD OF THE
SECOND AND MORE AMPLIFIED SHORTWAVE. A SURFACE LOW IS EXPECTED
DEVELOP FROM THE GULF COAST TOWARD THE CAROLINA COAST DURING THE DAY
TUESDAY...THOUGH THE LOW TRACK IS STILL VERY MUCH IN QUESTION. THE
GFS IS SEVERAL MB LOWER AND FURTHER WEST THAN THE WEAKER/OFFSHORE
ECMWF. AS USUAL...THIS WILL PLAY A MAJOR ROLE IN EXACTLY WHERE A
TRANSITION ZONE (LIKELY SHARP) BETWEEN MORE FROZEN AND MORE LIQUID
PRECIP WOULD END UP. BASED ON THE PRECEDING AIRMASS MONDAY/MONDAY
NIGHT AND PTYPE NOMOGRAMS...CURRENTLY FEEL THAT PRECIP WILL STAND A
GOOD CHANCE OF BEING ALL SNOW AT ONSET MONDAY NIGHT/EARLY TUESDAY
AND THAT A LARGER-THAN-TYPICAL AREA COULD SEE SEVERAL HOURS OF A
LEAST A WINTRY MIX TUESDAY. SURFACE TEMPS WOULD ALSO BE FAVORABLE
FOR ACCUMULATION. THUS...WHILE CONFIDENCE IN THE DETAILS OF THE
FORECAST IS LOW...CONFIDENCE IS MEDIUM AND SLOWLY GROWING THAT THIS
SHOULD BE AT LEAST AN ADVISORY EVENT.
GIVEN THAT MODELS STILL AREN`T INITIALIZING WITH MUCH INFORMATION ON
THE MAIN PLAYERS IN THIS SYSTEM AND ARE STILL VERY DIFFERENT...THE
BEST COURSE OF ACTION WITH THIS FORECAST PACKAGE MAY BE TO JUST
CONTINUE THE ADVERTISED PTYPES.
THE SURFACE LOW WILL LIFT OFF TO THE NORTHEAST WEDNESDAY...WITH
PRECIP ENDING (POSSIBLY AS SNOW) BY WEDNESDAY AFTERNOON. ANOTHER
BLAST OF ARCTIC AIR IS EXPECTED ON ITS HEELS FOR LATE WEEK AS THE
TRAIN OF SHORTWAVES INTO THE EAST COAST TROUGH CONTINUES. MODELS
ARE TRENDING COLDER FOR THURS THROUGH SATURDAY...WITH ANOTHER ROUND
OF LOWS IN THE TEENS OR SINGLE DIGITS AND HIGHS IN THE 30S POSSIBLE.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
AS OF 700 AM SATURDAY...
LIGHT SOUTH TO SOUTHWESTERLY WINDS THIS MORNING WILL BECOME SW TO
SSW AND STEADILY INCREASE AFTER 14Z...IN STRENGTHENING FLOW BETWEEN
MODIFIED ARCTIC HIGH PRESSURE ALONG AND OFFSHORE THE SE US
COAST...AND A POWERFUL ARCTIC COLD FRONT APPROACHING FROM THE
NORTHWEST. AN AREA OF ALTOCUMULUS WILL SWEEP EAST AND GRAZE MAINLY
THE NORTHERN HALF OF THE FORECAST AREA AROUND MIDDAY...AMIDST AN
OTHERWISE MOSTLY CLEAR SKY.
THE APPROACHING ARCTIC COLD FRONT WILL THEN BRING A FRIGID AND WINDY
BLAST OF AIR THROUGH CENTRAL NC THIS EVENING...AT WHICH TIME
NORTHWESTERLY WIND GUSTS OF 35 TO 45 MPH WILL BE COMMON...THE
STRONGEST OF WHICH WILL OCCUR WITHIN THE FIRST FEW HOURS OF FRONTAL
PASSAGE. A TEMPO GROUP HAS BEEN ADDED TO HIGHLIGHT THIS OCCURRENCE
AND TIMING AT THE RESPECTIVE TAF SITES. A FEW SHOWERS OR SPRINKLES
WILL ALSO ACCOMPANY THE FRONT...MOST LIKELY AT KRDU AND KRWI...THE
LATTER OF WHICH MAY EXPERIENCE A FEW WET SNOW FLAKES OR FLURRIES AS
WELL. WHILE THERE IS A SLIGHT CHANCE OF A BRIEF MVFR CEILING AND/OR
VISIBILITY RESTRICTION IN ASSOCIATION WITH ANY LOCALLY HEAVIER
PRECIPITATION...ODDS ARE THAT CONDITIONS WILL REMAIN VFR EVEN WHERE
PRECIPITATION BRIEFLY OCCURS.
OUTLOOK: WIDESPREAD SUB-VFR CONDITIONS AND PRECIPITATION...
INCLUDING SOME WINTRY...WILL BE POSSIBLE IN ASSOCIATION WITH A
COASTAL LOW MON NIGHT THROUGH TUE NIGHT...THOUGH FORECAST CONFIDENCE
REMAINS LOWER THAN AVERAGE.
&&
.FIRE WEATHER...
AS OF 1055 AM SATURDAY...
AS NOTED IN THE NEAR-TERM DISCUSSION ABOVE...MIXING HEIGHTS RISE
THIS AFTERNOON WHICH SHOULD ALLOW FOR EFFICIENT TRANSPORT OF SOME
INCREASING WINDS ALOFT TO THE SURFACE. CURRENTLY ANTICIPATING WIND
GUSTS AT LEAST AROUND 30 MPH...THE COMBINED FORECAST OF LOW RELATIVE
HUMIDITIES AND THE WIND RESULTS IN FIRE WEATHER CONDITIONS FROM THE
TRIANGLE NORTH AND WEST SIMILAR TO THOSE OVER THE SANDHILLS AND
SOUTHERN COASTAL PLAIN. AS A RESULT...OPTED TO EXPAND THE RED FLAG
WARNING TO INCLUDE MUCH OF CENTRAL NORTH CAROLINA EXCEPT FOR THE
NORTHEAST PIEDMONT...WHERE MINIMUM RELATIVE HUMIDITIES ARE FORECAST
TO BE JUST A LITTLE HIGHER COMPARED TO THE REST OF THE AREA.
LINGERING BLUSTERY CONDITIONS ON SUNDAY...IN CONJUNCTION WITH LOW
RELATIVE HUMIDITY VALUES AROUND 20 PERCENT...MAY RESULT IN YET
ANOTHER DAY OF ELEVATED FIRE RISK...PARTICULARLY OVER THE EASTERN
HALF OF CENTRAL NC WHERE WINDS WILL BE STRONGEST (GUSTS 25 TO 30
MPH) RELATIVELY LONGEST (THROUGH EARLY-MID AFTERNOON). COLD
TEMPERATURES ONLY IN THE 20S TO LOWER 30S MAY MITIGATE THE OVERALL
THREAT...HOWEVER. WE WILL COORDINATE WITH THE NC FOREST SERVICE
LATER TODAY REGARDING FIRE RISK FOR SUNDAY.
&&
.CLIMATE...
THE FOLLOWING ARE TEMPERATURE RECORDS FOR FEBRUARY 15 AND 16:
RECORD LOWS
GSO RDU FAY
FEBRUARY 15: 6 IN 1943 6 IN 1899 12 IN 1943
FEBRUARY 16: 8 IN 1905 11 IN 1905 17 IN 1991
RECORD LOW MAXIMUMS
GSO RDU FAY
FEBRUARY 15: 28 IN 1943 29 IN 1943 36 IN 1965
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING FROM NOON TODAY TO 6 PM EST THIS EVENING FOR
NCZ007-021>025-028-038>043-073>078-083>086-088-089.
WIND ADVISORY FROM 7 PM THIS EVENING TO 6 AM EST SUNDAY FOR
NCZ008>011-024>028-040>043-074>078-085-086-088-089.
WIND ADVISORY FROM 4 PM THIS AFTERNOON TO 6 AM EST SUNDAY FOR
NCZ007-021>023-038-039.
&&
$$
SYNOPSIS...RAH
NEAR TERM...RAH
SHORT TERM...RAH
LONG TERM...SMITH
AVIATION...RAH
FIRE WEATHER...RAH
CLIMATE...RAH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
724 AM EST SAT FEB 14 2015
.SYNOPSIS...
ARCTIC HIGH PRESSURE ALONG THE SOUTH ATLANTIC COAST
WILL MOVE OFFSHORE TODAY...IN ADVANCE OF AN ARCTIC COLD FRONT THAT
WILL BLAST ACROSS OUR REGION THIS EVENING. ARCTIC HIGH PRESSURE WILL
FOLLOW AND BUILD ACROSS THE MIDDLE ATLANTIC STATES TONIGHT THROUGH
MON.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 720 AM SATURDAY...
YET ANOTHER POTENT PV ANOMALY...DRIVEN BY A 130 KT MID LEVEL JET
STREAK IN NW FLOW...WILL AMPLIFY SHARPLY FROM THE GREAT LAKES TO THE
MIDDLE ATLANTIC COAST THROUGH TONIGHT. AN ACCOMPANYING SFC LOW WILL
UNDERGO DEEPENING AND ULTIMATELY BOMB AS IT TRACKS FROM THE EASTERN
GREAT LAKES TO THE MIDDLE ATLANTIC AND NEW ENGLAND COASTS...WITH A
TRAILING ARCTIC COLD FRONT POISED TO SURGE SSE ACROSS CENTRAL NC
THIS EVENING.
AHEAD OF THE FRONT...A BREEZY AND RELATIVELY MILD SW WIND WILL GUST
BETWEEN 20 AND 30 MPH...WITH PARTLY TO MOSTLY SUNNY SKIES FOR THE
MAJORITY OF THE DAY. TEMPERATURES OFTEN PROVE WARMER THAN FORECAST
IN CASES OF STRONG SW FLOW...LIKE TODAY. WITH THAT IN MIND...AND
BASED ON RECENT RUNS OF THE HRRR AND RAP...AND WITH SUPPORT FROM THE
MAV MOS...HIGH TEMPERATURES HAVE BEEN ADJUSTED MILDER YET - INTO THE
LOWER TO MIDDLE 50S...WITH SOME UPPER 50S POSSIBLE OVER THE SOUTHERN
PIEDMONT AND SANDHILLS. SIMILAR TO WHAT OCCURRED ON THU...A
SHIELD/BAND OF BKN TO OVC STRATOCUMULUS AND PRECIPITATION WILL
SPREAD/DEVELOP EASTWARD ACROSS CENTRAL NC DURING THE LATE AFTERNOON
AND EVENING. SPOTTY LIGHT SHOWERS OR SPRINKLES MAY OVERCOME AN
OTHERWISE RELATIVELY DEEP ~6 THOUSAND FT SUB-CLOUD LAYER...MAINLY
FROM THE TRIANGLE AND POINTS NORTHEAST...IN CLOSEST PROXIMITY TO A
240 M/12 HR PRESSURE FALL CENTER FOCUSED OVER THE CHESAPEAKE BAY AND
DELMARVA AT 06Z/15TH. ALSO SIMILAR TO THU...FLURRIES OR LIGHT SNOW
MAY MIX WITH THE OTHERWISE LIQUID PRECIPITATION AS IT DEPARTS DURING
THE MID-LATE EVENING.
THE BIGGER STORY WILL BE THE WIND...COLD...AND COMBINATION OF THE
TWO IN THE FORM OF LOW WIND CHILLS...WHICH WILL FOLLOW THE FRONT.
THOUGH THE SFC LAYER MAY BRIEFLY DECOUPLE AND RESULT IN A RELATIVE
MINIMUM IN WIND AROUND SUNSET...BRUTAL CAA DRIVEN BY 3-HOURLY 7-10
MB MSL PRESSURE RISES (STRONGEST OVER WESTERN AND WEST-CENTRAL VA)
WILL CAUSE THE BOUNDARY LAYER TO MIX STRONGLY AND SUPPORT...PER BUFR
FORECAST SOUNDINGS...A FEW HOUR PERIOD OF WIND GUSTS BETWEEN 35 AND
45 MPH - SLIGHTLY WEAKER OVER THE SOUTHERN PIEDMONT AND WITH A FEW
GUSTS BETWEEN 45 AND 50 MPH POSSIBLE FROM THE NORTHERN PIEDMONT TO
THE NORTHERN AND CENTRAL COASTAL PLAIN. WHILE EXTREME FOR CENTRAL NC
STANDARDS...THIS SYSTEM LOOKS EVEN MORE POTENT THAN THE ONE FROM
THU...WHICH PRODUCED MULTIPLE WIND GUSTS BETWEEN 40 AND 45 MPH OVER
THE NW PIEDMONT...SANDHILLS...AND CENTRAL COASTAL PLAIN. A WIND
ADVISORY HAS CONSEQUENTLY BEEN ISSUED FOR ALL BUT THE SOUTHERN
PIEDMONT...THOUGH THOSE COUNTIES TOO MAY ULTIMATELY BE INCLUDED IN
THE ADVISORY GIVEN THE POTENTIAL FOR A BRIEF BURST OF AROUND 40 MPH
WINDS IMMEDIATELY BEHIND THE FRONT...EVEN THERE.
THE COMBINATION OF WIND...LESSENING LATE WHEN LOW TEMPERATURES IN
THE LOW-MID TEENS TO AROUND 20 DEGREES OR SO ARE EXPECTED TO BE
ACHIEVED...WILL SUPPORT LOW MINIMUM WIND CHILL VALUES MOSTLY BETWEEN
ZERO AND TEN ABOVE. HOWEVER...CONFIDENCE IN LOW TEMPERATURES TONIGHT
IS LOWER THAN WHAT WOULD BE EXPECTED FOR A SECOND PERIOD
FORECAST...SINCE MOS GUIDANCE IS A SOLID 5-10 DEGREES HIGHER THAN 2
METER TEMPERATURE OUTPUT FROM JUST ABOUT ALL AVAILABLE MODEL
GUIDANCE. SUSPECT MOS MAY BE STRUGGLING WITH THE UNUSUALLY DEEP
MIXED LAYER IN STRONG CAA OVERNIGHT...BUT WILL DEFER TO THE DAY
SHIFT FOR WHETHER OR NOT LOWS NEED TO BE ADJUSTED DOWNWARD...WHICH
WOULD THEN SUPPORT SOME WIND CHILLS IN THE FIVE BELOW ZERO TO ZERO
RANGE GENERALLY NORTH OF HWY 64...AND WHICH WOULD NECESSITATE THE
ISSUANCE OF A WIND CHILL ADVISORY FOR THOSE AREAS.
&&
.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
AS OF 350 AM SATURDAY...
ARCTIC SFC HIGH PRESSURE WILL MODIFY/WEAKEN AS IT BUILDS FROM THE
UPPER MIDWEST TOWARD THE CENTRAL APPALACHIANS THROUGH MON MORNING.
SKIES WILL BE CLEAR SUNDAY IN STRONGLY SUBSIDENT CONDITIONS BEHIND
THE POTENT UPPER TROUGH FORECAST TO CROSS OUR REGION DURING THE NEAR
TERM...FOLLOWED BY INCREASING HIGH CLOUDS SUN EVE AND ESPECIALLY
OVERNIGHT...DOWNSTREAM OF THE COMPLEX AMALGAMATION OF SHORTWAVE
TROUGHS FORECAST TO AFFECT CENTRAL NC EARLY NEXT WEEK. AFTER
CONTINUED BLUSTERY CONDITIONS EARLY SUN...NW WINDS WILL LESSEN AND
CERTAINLY BECOME LESS GUSTY BY MID-LATE AFTERNOON. WITH THE LOW
LEVEL THERMAL TROUGH OVERHEAD...ONLY UPPER 20S TO LOWER 30S ARE
ANTICIPATED FOR HIGHS. SIMILARLY VERY COLD LOWS IN THE TEENS...WITH
SOME SINGLE DIGITS PROBABLE IN THE TYPICALLY COLDER AREAS OF THE
PIEDMONT.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 345 AM SATURDAY...
WINTER WEATHER POSSIBLE EARLY NEXT WEEK..
CONFIDENCE REMAINS LOW REGARDING POSSIBLE WINTRY PRECIP MONDAY AND
TUESDAY OF NEXT WEEK...AND THE 00Z MODEL QUITE DID NOT OFFER ANY
CONVERGENCE TOWARD A SIMILAR SOLUTION.
THE GENERAL SETUP WILL BE FOR A PAIR OF SHORTWAVES CURRENTLY OVER
OFF THE NORTHERN PACIFIC...WHICH IS A MESS ON WATER VAPOR WITH
NUMEROUS DISTURBANCES TOPPING THE UPPER RIDGE...TO DIVE SOUTHEAST
ACROSS THE ROCKIES AND THEN EAST. THE FIRST WAVE IS FORECAST TO
RACE EAST ACROSS THE OHIO VALLEY ON MONDAY...FOLLOWED BY A MORE
AMPLIFIED WAVE...WHICH ABSORBS A WEAK DISTURBANCE CURRENTLY OFF THE
CALIFORNIA BAJA...THAT CROSSES THE DEEP SOUTH ON TUESDAY. THE MAIN
QUESTIONS IN THE FORECAST ARE HOW QUICKLY PRECIP SPREADS EAST ACROSS
THE TENNESSEE VALLEY AND WHERE THE SURFACE LOW (OR MULTIPLE SURFACE
WAVES TRACK). MODELS SEEM TO BE STRUGGLING THE MOST WITH THE LEAD
WAVE...WITH THE ECMWF OUTPACING THE GFS BY 6 TO 12 HORUS RIGHT OFF
THE BAT BY BRINGING MEASURABLE PRECIP ACROSS ALL OF CENTRAL NC BY
MONDAY AFTERNOON/EVENING. DRIVEN MAINLY BY RIGHT JET ENTRANCE UPPER
DIVERGENCE...THE ECMWF LOOKS TOO WET/FAST/NORTH AND IS NOT SUPPORTED
BY THE NAM OR GFS FOR MONDAY. WILL MAINTAIN A SLIGHT CHANCE OF SNOW
ACROSS THE WESTERN/SOUTHERN PIEDMONT MONDAY AFTERNOON AND EARLY
EVENING TO ACCOUNT FOR THIS POSSIBILITY. EXPECT HIGHS MONDAY TO BE
LOWER THAN GUIDANCE GIVEN THAT THERE SHOULD BE WIDESPREAD MID/HIGH
CLOUDS....EVEN WITHOUT PRECIP...AFTER A VERY COLD START AND GUIDANCE
IS CLOSE TO FULL SUN THICKNESS VALUES. HIGHS 30-35.
THE MORE IMPACTFUL WEATHER POTENTIAL COMES MONDAY NIGHT AND TUESDAY
AS STRONGER HEIGHT FALLS SPREAD ACROSS THE SOUTHEAST AHEAD OF THE
SECOND AND MORE AMPLIFIED SHORTWAVE. A SURFACE LOW IS EXPECTED
DEVELOP FROM THE GULF COAST TOWARD THE CAROLINA COAST DURING THE DAY
TUESDAY...THOUGH THE LOW TRACK IS STILL VERY MUCH IN QUESTION. THE
GFS IS SEVERAL MB LOWER AND FURTHER WEST THAN THE WEAKER/OFFSHORE
ECMWF. AS USUAL...THIS WILL PLAY A MAJOR ROLE IN EXACTLY WHERE A
TRANSITION ZONE (LIKELY SHARP) BETWEEN MORE FROZEN AND MORE LIQUID
PRECIP WOULD END UP. BASED ON THE PRECEDING AIRMASS MONDAY/MONDAY
NIGHT AND PTYPE NOMOGRAMS...CURRENTLY FEEL THAT PRECIP WILL STAND A
GOOD CHANCE OF BEING ALL SNOW AT ONSET MONDAY NIGHT/EARLY TUESDAY
AND THAT A LARGER-THAN-TYPICAL AREA COULD SEE SEVERAL HOURS OF A
LEAST A WINTRY MIX TUESDAY. SURFACE TEMPS WOULD ALSO BE FAVORABLE
FOR ACCUMULATION. THUS...WHILE CONFIDENCE IN THE DETAILS OF THE
FORECAST IS LOW...CONFIDENCE IS MEDIUM AND SLOWLY GROWING THAT THIS
SHOULD BE AT LEAST AN ADVISORY EVENT.
GIVEN THAT MODELS STILL AREN`T INITIALIZING WITH MUCH INFORMATION ON
THE MAIN PLAYERS IN THIS SYSTEM AND ARE STILL VERY DIFFERENT...THE
BEST COURSE OF ACTION WITH THIS FORECAST PACKAGE MAY BE TO JUST
CONTINUE THE ADVERTISED PTYPES.
THE SURFACE LOW WILL LIFT OFF TO THE NORTHEAST WEDNESDAY...WITH
PRECIP ENDING (POSSIBLY AS SNOW) BY WEDNESDAY AFTERNOON. ANOTHER
BLAST OF ARCTIC AIR IS EXPECTED ON ITS HEELS FOR LATE WEEK AS THE
TRAIN OF SHORTWAVES INTO THE EAST COAST TROUGH CONTINUES. MODELS
ARE TRENDING COLDER FOR THURS THROUGH SATURDAY...WITH ANOTHER ROUND
OF LOWS IN THE TEENS OR SINGLE DIGITS AND HIGHS IN THE 30S POSSIBLE.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
AS OF 130 AM SATURDAY...
CALM TO OCCASIONALLY LIGHT SOUTHERLY WINDS THIS MORNING WILL BECOME
SW TO SSW AND STEADILY INCREASE AFTER 14Z...IN STRENGTHENING FLOW
BETWEEN MODIFIED ARCTIC HIGH PRESSURE ALONG AND OFFSHORE THE SE US
COAST...AND A POWERFUL ARCTIC COLD FRONT APPROACHING FROM THE
NORTHWEST. AN AREA OF ALTOCUMULUS WILL SWEEP EAST AND GRAZE MAINLY
THE NORTHERN HALF OF THE FORECAST AREA AROUND MIDDAY...AMIDST AN
OTHERWISE MOSTLY CLEAR SKY.
THE APPROACHING ARCTIC COLD FRONT WILL THEN BRING A FRIGID AND WINDY
BLAST OF AIR THROUGH CENTRAL NC THIS EVENING...AT WHICH TIME
NORTHWESTERLY WIND GUSTS OF 35 TO 45 MPH WILL BE COMMON...THE
STRONGEST OF WHICH WILL OCCUR WITHIN THE FIRST FEW HOURS OF FRONTAL
PASSAGE. A TEMPO GROUP HAS BEEN ADDED TO HIGHLIGHT THIS OCCURRENCE
AND TIMING AT THE RESPECTIVE TAF SITES. A FEW SHOWERS OR SPRINKLES
WILL ALSO ACCOMPANY THE FRONT...MOST LIKELY AT KRDU AND KRWI...THE
LATTER OF WHICH MAY EXPERIENCE A FEW WET SNOW FLAKES OR FLURRIES AS
WELL. WHILE THERE IS A SLIGHT CHANCE OF A BRIEF MVFR CEILING AND/OR
VISIBILITY RESTRICTION IN ASSOCIATION WITH ANY LOCALLY HEAVIER
PRECIPITATION...ODDS ARE THAT CONDITIONS WILL REMAIN VFR EVEN WHERE
PRECIPITATION BRIEFLY OCCURS.
OUTLOOK: WIDESPREAD SUB-VFR CONDITIONS AND PRECIPITATION...
INCLUDING SOME WINTRY...WILL BE POSSIBLE IN ASSOCIATION WITH A
COASTAL LOW MON NIGHT THROUGH TUE NIGHT...THOUGH FORECAST CONFIDENCE
REMAINS LOWER THAN AVERAGE.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
AS OF 700 AM SATURDAY...
LIGHT SOUTH TO SOUTHWESTERLY WINDS THIS MORNING WILL BECOME SW TO
SSW AND STEADILY INCREASE AFTER 14Z...IN STRENGTHENING FLOW BETWEEN
MODIFIED ARCTIC HIGH PRESSURE ALONG AND OFFSHORE THE SE US
COAST...AND A POWERFUL ARCTIC COLD FRONT APPROACHING FROM THE
NORTHWEST. AN AREA OF ALTOCUMULUS WILL SWEEP EAST AND GRAZE MAINLY
THE NORTHERN HALF OF THE FORECAST AREA AROUND MIDDAY...AMIDST AN
OTHERWISE MOSTLY CLEAR SKY.
THE APPROACHING ARCTIC COLD FRONT WILL THEN BRING A FRIGID AND WINDY
BLAST OF AIR THROUGH CENTRAL NC THIS EVENING...AT WHICH TIME
NORTHWESTERLY WIND GUSTS OF 35 TO 45 MPH WILL BE COMMON...THE
STRONGEST OF WHICH WILL OCCUR WITHIN THE FIRST FEW HOURS OF FRONTAL
PASSAGE. A TEMPO GROUP HAS BEEN ADDED TO HIGHLIGHT THIS OCCURRENCE
AND TIMING AT THE RESPECTIVE TAF SITES. A FEW SHOWERS OR SPRINKLES
WILL ALSO ACCOMPANY THE FRONT...MOST LIKELY AT KRDU AND KRWI...THE
LATTER OF WHICH MAY EXPERIENCE A FEW WET SNOW FLAKES OR FLURRIES AS
WELL. WHILE THERE IS A SLIGHT CHANCE OF A BRIEF MVFR CEILING AND/OR
VISIBILITY RESTRICTION IN ASSOCIATION WITH ANY LOCALLY HEAVIER
PRECIPITATION...ODDS ARE THAT CONDITIONS WILL REMAIN VFR EVEN WHERE
PRECIPITATION BRIEFLY OCCURS.
OUTLOOK: WIDESPREAD SUB-VFR CONDITIONS AND PRECIPITATION...
INCLUDING SOME WINTRY...WILL BE POSSIBLE IN ASSOCIATION WITH A
COASTAL LOW MON NIGHT THROUGH TUE NIGHT...THOUGH FORECAST CONFIDENCE
REMAINS LOWER THAN AVERAGE.
&&
.FIRE WEATHER...
AS OF 700 AM SATURDAY
A BREEZY AND RELATIVELY MILD (TEMPS IN THE 50S) SOUTHWESTERLY WIND
WILL INCREASE INTO THE 15-20 KT RANGE...WITH GUSTS BETWEEN 25 AND 30
KTS - STRONGEST OVER THE SANDHILLS AND COASTAL PLAIN. IN
ADDITION...MINIMUM RELATIVE HUMIDITY VALUES WILL FALL TO AROUND 25
PERCENT...AS TEMPERATURES RISE INTO THE 50S...AND DRYNESS IN
ASSOCIATION WITH A LINGERING MODIFIED ARCTIC SURFACE RIDGE REMAINS.
LINGERING BLUSTERY CONDITIONS ON SUNDAY...IN CONJUNCTION WITH LOW
RELATIVE HUMIDITY VALUES AROUND 20 PERCENT...MAY RESULT IN YET
ANOTHER DAY OF ELEVATED FIRE RISK...PARTICULARLY OVER THE EASTERN
HALF OF CENTRAL NC WHERE WINDS WILL BE STRONGEST (GUSTS 25 TO 30
MPH) RELATIVELY LONGEST (THROUGH EARLY-MID AFTERNOON). COLD
TEMPERATURES ONLY IN THE 20S TO LOWER 30S MAY MITIGATE THIE OVERALL
THREAT...HOWEVER. WE WILL COORDINATE WITH THE NC FOREST SERVICE AGAIN
TODAY REGARDING FIRE RISK FOR SUNDAY.
&&
.CLIMATE...
THE FOLLOWING ARE TEMPERATURE RECORDS FOR FEBRUARY 15 AND 16:
RECORD LOWS
GSO RDU FAY
FEBRUARY 15: 6 IN 1943 6 IN 1899 12 IN 1943
FEBRUARY 16: 8 IN 1905 11 IN 1905 17 IN 1991
RECORD LOW MAXIMUMS
GSO RDU FAY
FEBRUARY 15: 28 IN 1943 29 IN 1943 36 IN 1965
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING FROM NOON TODAY TO 6 PM EST THIS EVENING FOR
NCZ028-042-043-073>078-083>086-088-089.
WIND ADVISORY FROM 7 PM THIS EVENING TO 6 AM EST SUNDAY FOR
NCZ008>011-024>028-040>043-074>078-085-086-088-089.
WIND ADVISORY FROM 4 PM THIS AFTERNOON TO 6 AM EST SUNDAY FOR
NCZ007-021>023-038-039.
&&
$$
SYNOPSIS...RAH
NEAR TERM...RAH
SHORT TERM...RAH
LONG TERM...SMITH
AVIATION...RAH
FIRE WEATHER...RAH
CLIMATE...RAH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
350 AM EST SAT FEB 14 2015
.SYNOPSIS...ARCTIC HIGH PRESSURE ALONG THE SOUTH ATLANTIC COAST
WILL MOVE OFFSHORE TODAY...IN ADVANCE OF AN ARCTIC COLD FRONT THAT
WILL BLAST ACROSS OUR REGION THIS EVENING. ARCTIC HIGH PRESSURE WILL
FOLLOW AND BUILD ACROSS THE MIDDLE ATLANTIC STATES TONIGHT THROUGH
MON.
&&
.NEAR TERM /THROUGH SATURDAY/...
AS OF 945 PM FRIDAY...
TONIGHT...HIGH CLOUDS HAVE MOVED OFF TO THE EAST AND SKIES HAVE
CLEARED OUT ACROSS THE CWA...AT THE SAME TIME WINDS HAVE
CALMED...SETTING UP OPTIMAL CONDITIONS FOR RADIATIONAL COOLING.
TEMPERATURES ARE CURRENTLY HOLDING IN THE MID TO UPPER 20S. DUAL
SHORTWAVES TO THE WEST...ONE PASSING NORTH OF THE AREA...AND THE
OTHER DIVING SOUTHWEST OF CENTRAL NC HAVE LEFT A VOID IN UPSTREAM
MOISTURE. ALTHOUGH FORECAST SOUNDINGS LOOK FAIRLY GOOD FOR
OROGRAPHIC CIRRUS ENHANCEMENT...THE UPPER LEVEL MOISTURE IS REALLY
LACKING AND IT WILL BE HARD TO GENERATE ANYTHING THE REST OF THE
NIGHT AND THIS MORNING ALTHOUGH THERE IS ONE AREA OF SLIGHTLY
ENHANCED MOISTURE MOVING ACROSS EASTERN KY THAT BEARS WATCHING AS IT
APPROACHES THE APPALACHIANS. AFTER MIDNIGHT...THERE IS SOME
EXPECTATION THAT WINDS WILL INCREASE A LITTLE BIT WITH A VERY
SHALLOW MIXED LAYER. RAP SOUNDINGS SHOW THIS SHOULD BE MOST
PREDOMINANT IN THE TRIAD WITH WINDS UP TO 8 KTS OR SO POSSIBLE AT
TIMES. THE UPSHOT OF THIS COULD BE A FAIRLY SPOTTY MINIMUM
TEMPERATURE MAP AS SOME AREAS MAINTAIN OPTIMAL RADIATIONAL
COOLING...AND OTHERS DO NOT. IN GENERAL EXPECT UPPER TEENS TO LOW
20S FOR LOWS BUT DO NOT BE SURPRISED TO SEE A COUPLE OF LOW TO MID
TEENS READINGS THROUGH IN THERE. -ELLIS
SATURDAY...A LEE SIDE TROUGH WILL SHARPEN IN THE AFTERNOON AS
ANOTHER ARCTIC COLD FRONT APPROACHES FROM THE NW AND THE SFC HIGH
SETS UP OVER THE NORTHERN GULF. THIS SET-UP WILL RESULT IN A
STRENGTHENING SW LOW LEVEL FLOW. IN THESE EVENTS...USUALLY SEE A
LARGER THAN NORMAL DIURNAL TEMP RECOVERY. AFTER MIN TEMPS IN THE
TEENS/LOWER 20S...POTENTIAL FOR TEMPS TO RISE A SOLID 30
DEGREES...POSSIBLY 35. HAVE GONE CONSERVATIVE WITH MAX TEMPS NEAR 50-
LOWER 50S BUT WOULD NOT BE SURPRISED TO SEE SOME MID-UPPER 50S INT EH
FAR SOUTH-SE AND MID 50S AS FAR NORTH AS RDU. EXPECT A STOUT SW WIND
15-20MPH IN THE AFTERNOON WITH GUSTS 28-33 MPH. THESE WIND
PARAMETERS ALONG WITH A DRY AIR MASS WILL RESULT IN CRITICAL FIRE
WEATHER CONDITIONS (SEE FIRE WEATHER SECTION BELOW).
MAY SEE AN INCREASE IN CLOUD COVERAGE LATE IN THE DAY AS THE ARCTIC
BOUNDARY GETS CLOSER. -WSS
&&
.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/...
AS OF 325 PM FRIDAY...
ARCTIC FRONT...BEING PUSHED
ALONG BY A STRONG S/W CROSSING THE EASTERN LAKES INTO THE NORTHERN
MID ATLANTIC...WILL PLOW SEWD ACROSS CENTRAL NC SATURDAY EVENING.
SIMILAR TO THURSDAY`S EVENT...MAY SEE A FEW RAIN SHOWERS OR
SPRINKLES/FLURRIES ACROSS THE NE PIEDMONT AND NORTHERN COASTAL PLAIN
SATURDAY EVENING BEHIND THE FRONT. FRONTAL PASSAGE WILL BE NOTED BY
SFC WINDS VEERING TO THE NW AND GUSTING AS HIGH AS 40-45 MPH 2-4
HOURS AFTER FROPA THEN "SUBSIDE" 25-35 MPH GUSTS OVERNIGHT. THIS
FLOW WILL ADVECT A VERY COLD DRY AIR MASS INTO CENTRAL NC. APPEARS
TO BE ENOUGH MIXING TO HELP TO KEEP TEMPS UP A BIT FROM EARLIER
THINKING. MIN TEMPS 15 NW TO NEAR 20 SE. RESULTANT WIND CHILLS IN
THE SINGLE DIGITS APPEAR LIKELY...POSSIBLY CLOSE TO WIND CHILL
ADVISORY CRITERIA IN THE NORTHERN PIEDMONT.
BLUSTERY NW WINDS WILL PERSIST INTO SUNDAY MORNING-EARLY AFTERNOON
UNDER SUNNY-MOSTLY SUNNY SKIES. WITH 850MB THERMAL TROUGH OVER THE
REGION...STRONG PROBABILITY THAT MUCH OF THE REGION WILL REMAIN
BELOW FREEZING. NEXT SYSTEM EXPECTED TO APPROACH FROM THE WEST-NW
LATE SUNDAY NIGHT. BASED ON TIMING...THIS MAY INCREASE HIGH LEVEL
CLOUDS ACROSS THE REGION AFTER MIDNIGHT. STILL...WITH AN ARCTIC AIR
MASS IN PLACE AND WINDS LIKELY BECOME CALM AT SUNSET...SHOULD SEE
TEMPS FALL INTO THE 12-17 DEGREE RANGE WITH A FEW 5-10 ABOVE
POSSIBLE IN THE NORMALLY COLDER LOCATIONS OF THE NE PIEDMONT.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 345 AM SATURDAY...
...WINTER WEATHER POSSIBLE EARLY NEXT WEEK..
CONFIDENCE REMAINS LOW REGARDING POSSIBLE WINTRY PRECIP MONDAY AND
TUESDAY OF NEXT WEEK...AND THE 00Z MODEL QUITE DID NOT OFFER ANY
CONVERGENCE TOWARD A SIMILAR SOLUTION.
THE GENERAL SETUP WILL BE FOR A PAIR OF SHORTWAVES CURRENTLY OVER
OFF THE NORTHERN PACIFIC...WHICH IS A MESS ON WATER VAPOR WITH
NUMEROUS DISTURBANCES TOPPING THE UPPER RIDGE...TO DIVE SOUTHEAST
ACROSS THE ROCKIES AND THEN EAST. THE FIRST WAVE IS FORECAST TO
RACE EAST ACROSS THE OHIO VALLEY ON MONDAY...FOLLOWED BY A MORE
AMPLIFIED WAVE...WHICH ABSORBS A WEAK DISTURBANCE CURRENTLY OFF THE
CALIFORNIA BAJA...THAT CROSSES THE DEEP SOUTH ON TUESDAY. THE MAIN
QUESTIONS IN THE FORECAST ARE HOW QUICKLY PRECIP SPREADS EAST ACROSS
THE TENNESSEE VALLEY AND WHERE THE SURFACE LOW (OR MULTIPLE SURFACE
WAVES TRACK). MODELS SEEM TO BE STRUGGLING THE MOST WITH THE LEAD
WAVE...WITH THE ECMWF OUTPACING THE GFS BY 6 TO 12 HORUS RIGHT OFF
THE BAT BY BRINGING MEASURABLE PRECIP ACROSS ALL OF CENTRAL NC BY
MONDAY AFTERNOON/EVENING. DRIVEN MAINLY BY RIGHT JET ENTRANCE UPPER
DIVERGENCE...THE ECMWF LOOKS TOO WET/FAST/NORTH AND IS NOT SUPPORTED
BY THE NAM OR GFS FOR MONDAY. WILL MAINTAIN A SLIGHT CHANCE OF SNOW
ACROSS THE WESTERN/SOUTHERN PIEDMONT MONDAY AFTERNOON AND EARLY
EVENING TO ACCOUNT FOR THIS POSSIBILITY. EXPECT HIGHS MONDAY TO BE
LOWER THAN GUIDANCE GIVEN THAT THERE SHOULD BE WIDESPREAD MID/HIGH
CLOUDS....EVEN WITHOUT PRECIP...AFTER A VERY COLD START AND GUIDANCE
IS CLOSE TO FULL SUN THICKNESS VALUES. HIGHS 30-35.
THE MORE IMPACTFUL WEATHER POTENTIAL COMES MONDAY NIGHT AND TUESDAY
AS STRONGER HEIGHT FALLS SPREAD ACROSS THE SOUTHEAST AHEAD OF THE
SECOND AND MORE AMPLIFIED SHORTWAVE. A SURFACE LOW IS EXPECTED
DEVELOP FROM THE GULF COAST TOWARD THE CAROLINA COAST DURING THE DAY
TUESDAY...THOUGH THE LOW TRACK IS STILL VERY MUCH IN QUESTION. THE
GFS IS SEVERAL MB LOWER AND FURTHER WEST THAN THE WEAKER/OFFSHORE
ECMWF. AS USUAL...THIS WILL PLAY A MAJOR ROLE IN EXACTLY WHERE A
TRANSITION ZONE (LIKELY SHARP) BETWEEN MORE FROZEN AND MORE LIQUID
PRECIP WOULD END UP. BASED ON THE PRECEDING AIRMASS MONDAY/MONDAY
NIGHT AND PTYPE NOMOGRAMS...CURRENTLY FEEL THAT PRECIP WILL STAND A
GOOD CHANCE OF BEING ALL SNOW AT ONSET MONDAY NIGHT/EARLY TUESDAY
AND THAT A LARGER-THAN-TYPICAL AREA COULD SEE SEVERAL HOURS OF A
LEAST A WINTRY MIX TUESDAY. SURFACE TEMPS WOULD ALSO BE FAVORABLE
FOR ACCUMULATION. THUS...WHILE CONFIDENCE IN THE DETAILS OF THE
FORECAST IS LOW...CONFIDENCE IS MEDIUM AND SLOWLY GROWING THAT THIS
SHOULD BE AT LEAST AN ADVISORY EVENT.
GIVEN THAT MODELS STILL AREN`T INITIALIZING WITH MUCH INFORMATION ON
THE MAIN PLAYERS IN THIS SYSTEM AND ARE STILL VERY DIFFERENT...THE
BEST COURSE OF ACTION WITH THIS FORECAST PACKAGE MAY BE TO JUST
CONTINUE THE ADVERTISED PTYPES.
THE SURFACE LOW WILL LIFT OFF TO THE NORTHEAST WEDNESDAY...WITH
PRECIP ENDING (POSSIBLY AS SNOW) BY WEDNESDAY AFTERNOON. ANOTHER
BLAST OF ARCTIC AIR IS EXPECTED ON ITS HEELS FOR LATE WEEK AS THE
TRAIN OF SHORTWAVES INTO THE EAST COAST TROUGH CONTINUES. MODELS
ARE TRENDING COLDER FOR THURS THROUGH SATURDAY...WITH ANOTHER ROUND
OF LOWS IN THE TEENS OR SINGLE DIGITS AND HIGHS IN THE 30S POSSIBLE.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
AS OF 130 AM SATURDAY...
CALM TO OCCASIONALLY LIGHT SOUTHERLY WINDS THIS MORNING WILL BECOME
SW TO SSW AND STEADILY INCREASE AFTER 14Z...IN STRENGTHENING FLOW
BETWEEN MODIFIED ARCTIC HIGH PRESSURE ALONG AND OFFSHORE THE SE US
COAST...AND A POWERFUL ARCTIC COLD FRONT APPROACHING FROM THE
NORTHWEST. AN AREA OF ALTOCUMULUS WILL SWEEP EAST AND GRAZE MAINLY
THE NORTHERN HALF OF THE FORECAST AREA AROUND MIDDAY...AMIDST AN
OTHERWISE MOSTLY CLEAR SKY.
THE APPROACHING ARCTIC COLD FRONT WILL THEN BRING A FRIGID AND WINDY
BLAST OF AIR THROUGH CENTRAL NC THIS EVENING...AT WHICH TIME
NORTHWESTERLY WIND GUSTS OF 35 TO 45 MPH WILL BE COMMON...THE
STRONGEST OF WHICH WILL OCCUR WITHIN THE FIRST FEW HOURS OF FRONTAL
PASSAGE. A TEMPO GROUP HAS BEEN ADDED TO HIGHLIGHT THIS OCCURRENCE
AND TIMING AT THE RESPECTIVE TAF SITES. A FEW SHOWERS OR SPRINKLES
WILL ALSO ACCOMPANY THE FRONT...MOST LIKELY AT KRDU AND KRWI...THE
LATTER OF WHICH MAY EXPERIENCE A FEW WET SNOW FLAKES OR FLURRIES AS
WELL. WHILE THERE IS A SLIGHT CHANCE OF A BRIEF MVFR CEILING AND/OR
VISIBILITY RESTRICTION IN ASSOCIATION WITH ANY LOCALLY HEAVIER
PRECIPITATION...ODDS ARE THAT CONDITIONS WILL REMAIN VFR EVEN WHERE
PRECIPITATION BRIEFLY OCCURS.
OUTLOOK: WIDESPREAD SUB-VFR CONDITIONS AND PRECIPITATION...
INCLUDING SOME WINTRY...WILL BE POSSIBLE IN ASSOCIATION WITH A
COASTAL LOW MON NIGHT THROUGH TUE NIGHT...THOUGH FORECAST CONFIDENCE
REMAINS LOWER THAN AVERAGE.
&&
.FIRE WEATHER...
AS OF 330 PM FRIDAY
A STOUT SW SFC WIND WITH SUSTAINED SPEEDS 15-20 MPH
AND GUSTS AROUND 30 MPH ALONG WITH LOW RH VALUES SIGNAL THE
POTENTIAL FOR RED FLAG CONDITIONS...MAINLY ACROSS THE SOUTH HALF OF
CENTRAL NC SATURDAY AFTERNOON. IN COORDINATION WITH THE NC FORESTRY
SERVICE...A FIRE WEATHER WATCH HAS BEEN FOR SATURDAY AFTERNOON FOR
AREAS GENERALLY SOUTH OF A GOLDSBORO-SANFORD-ALBEMARLE LINE. IF
CONDITIONS EARLY SATURDAY APPEAR SIMILAR...THE WATCH WILL BE
UPGRADED TO A RED FLAG WARNING MEANING ANY FIRES THAT OCCUR MAY
QUICKLY BURN OUT OF CONTROL.
OVER THE REMAINDER OF CENTRAL NC...AN INCREASE FIRE DANGER STATEMENT
WILL BE IN EFFECT AS PARAMETERS WILL BE JUST SHY OF RED FLAG
CRITERIA.
ESSENTIALLY...ANY OUTDOOR BURNING SHOULD BE DELAYED UNTIL LESS
VOLATILE CONDITIONS OCCUR.
&&
.CLIMATE...
THE FOLLOWING ARE TEMPERATURE RECORDS FOR FEBRUARY 15 AND 16:
RECORD LOWS
GSO RDU FAY
FEBRUARY 15: 6 IN 1943 6 IN 1899 12 IN 1943
FEBRUARY 16: 8 IN 1905 11 IN 1905 17 IN 1991
RECORD LOW MAXIMUMS
GSO RDU FAY
FEBRUARY 15: 28 IN 1943 29 IN 1943 36 IN 1965
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
FIRE WEATHER WATCH SATURDAY AFTERNOON FOR NCZ042-73>078-083>086-088-
089.
&&
$$
SYNOPSIS...RAH
NEAR TERM...ELLIS/WSS
SHORT TERM...WSS
LONG TERM...BLS
AVIATION...RAH
FIRE WEATHER...WSS
CLIMATE...RAH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
135 AM EST SAT FEB 14 2015
.SYNOPSIS...ARCTIC HIGH PRESSURE ALONG THE SOUTH ATLANTIC COAST
WILL MOVE OFFSHORE TODAY...IN ADVANCE OF AN ARCTIC COLD FRONT THAT
WILL BLAST ACROSS OUR REGION THIS EVENING. ARCTIC HIGH PRESSURE WILL
FOLLOW AND BUILD ACROSS THE MIDDLE ATLANTIC STATES TONIGHT THROUGH
MON.
&&
.NEAR TERM /THROUGH SATURDAY/...
AS OF 945 PM FRIDAY...
TONIGHT...HIGH CLOUDS HAVE MOVED OFF TO THE EAST AND SKIES HAVE
CLEARED OUT ACROSS THE CWA...AT THE SAME TIME WINDS HAVE
CALMED...SETTING UP OPTIMAL CONDITIONS FOR RADIATIONAL COOLING.
TEMPERATURES ARE CURRENTLY HOLDING IN THE MID TO UPPER 20S. DUAL
SHORTWAVES TO THE WEST...ONE PASSING NORTH OF THE AREA...AND THE
OTHER DIVING SOUTHWEST OF CENTRAL NC HAVE LEFT A VOID IN UPSTREAM
MOISTURE. ALTHOUGH FORECAST SOUNDINGS LOOK FAIRLY GOOD FOR
OROGRAPHIC CIRRUS ENHANCEMENT...THE UPPER LEVEL MOISTURE IS REALLY
LACKING AND IT WILL BE HARD TO GENERATE ANYTHING THE REST OF THE
NIGHT AND THIS MORNING ALTHOUGH THERE IS ONE AREA OF SLIGHTLY
ENHANCED MOISTURE MOVING ACROSS EASTERN KY THAT BEARS WATCHING AS IT
APPROACHES THE APPALACHIANS. AFTER MIDNIGHT...THERE IS SOME
EXPECTATION THAT WINDS WILL INCREASE A LITTLE BIT WITH A VERY
SHALLOW MIXED LAYER. RAP SOUNDINGS SHOW THIS SHOULD BE MOST
PREDOMINANT IN THE TRIAD WITH WINDS UP TO 8 KTS OR SO POSSIBLE AT
TIMES. THE UPSHOT OF THIS COULD BE A FAIRLY SPOTTY MINIMUM
TEMPERATURE MAP AS SOME AREAS MAINTAIN OPTIMAL RADIATIONAL
COOLING...AND OTHERS DO NOT. IN GENERAL EXPECT UPPER TEENS TO LOW
20S FOR LOWS BUT DO NOT BE SURPRISED TO SEE A COUPLE OF LOW TO MID
TEENS READINGS THROUGH IN THERE. -ELLIS
SATURDAY...A LEE SIDE TROUGH WILL SHARPEN IN THE AFTERNOON AS
ANOTHER ARCTIC COLD FRONT APPROACHES FROM THE NW AND THE SFC HIGH
SETS UP OVER THE NORTHERN GULF. THIS SET-UP WILL RESULT IN A
STRENGTHENING SW LOW LEVEL FLOW. IN THESE EVENTS...USUALLY SEE A
LARGER THAN NORMAL DIURNAL TEMP RECOVERY. AFTER MIN TEMPS IN THE
TEENS/LOWER 20S...POTENTIAL FOR TEMPS TO RISE A SOLID 30
DEGREES...POSSIBLY 35. HAVE GONE CONSERVATIVE WITH MAX TEMPS NEAR 50-
LOWER 50S BUT WOULD NOT BE SURPRISED TO SEE SOME MID-UPPER 50S INT EH
FAR SOUTH-SE AND MID 50S AS FAR NORTH AS RDU. EXPECT A STOUT SW WIND
15-20MPH IN THE AFTERNOON WITH GUSTS 28-33 MPH. THESE WIND
PARAMETERS ALONG WITH A DRY AIR MASS WILL RESULT IN CRITICAL FIRE
WEATHER CONDITIONS (SEE FIRE WEATHER SECTION BELOW).
MAY SEE AN INCREASE IN CLOUD COVERAGE LATE IN THE DAY AS THE ARCTIC
BOUNDARY GETS CLOSER. -WSS
&&
.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/...
AS OF 325 PM FRIDAY...
ARCTIC FRONT...BEING PUSHED
ALONG BY A STRONG S/W CROSSING THE EASTERN LAKES INTO THE NORTHERN
MID ATLANTIC...WILL PLOW SEWD ACROSS CENTRAL NC SATURDAY EVENING.
SIMILAR TO THURSDAY`S EVENT...MAY SEE A FEW RAIN SHOWERS OR
SPRINKLES/FLURRIES ACROSS THE NE PIEDMONT AND NORTHERN COASTAL PLAIN
SATURDAY EVENING BEHIND THE FRONT. FRONTAL PASSAGE WILL BE NOTED BY
SFC WINDS VEERING TO THE NW AND GUSTING AS HIGH AS 40-45 MPH 2-4
HOURS AFTER FROPA THEN "SUBSIDE" 25-35 MPH GUSTS OVERNIGHT. THIS
FLOW WILL ADVECT A VERY COLD DRY AIR MASS INTO CENTRAL NC. APPEARS
TO BE ENOUGH MIXING TO HELP TO KEEP TEMPS UP A BIT FROM EARLIER
THINKING. MIN TEMPS 15 NW TO NEAR 20 SE. RESULTANT WIND CHILLS IN
THE SINGLE DIGITS APPEAR LIKELY...POSSIBLY CLOSE TO WIND CHILL
ADVISORY CRITERIA IN THE NORTHERN PIEDMONT.
BLUSTERY NW WINDS WILL PERSIST INTO SUNDAY MORNING-EARLY AFTERNOON
UNDER SUNNY-MOSTLY SUNNY SKIES. WITH 850MB THERMAL TROUGH OVER THE
REGION...STRONG PROBABILITY THAT MUCH OF THE REGION WILL REMAIN
BELOW FREEZING. NEXT SYSTEM EXPECTED TO APPROACH FROM THE WEST-NW
LATE SUNDAY NIGHT. BASED ON TIMING...THIS MAY INCREASE HIGH LEVEL
CLOUDS ACROSS THE REGION AFTER MIDNIGHT. STILL...WITH AN ARCTIC AIR
MASS IN PLACE AND WINDS LIKELY BECOME CALM AT SUNSET...SHOULD SEE
TEMPS FALL INTO THE 12-17 DEGREE RANGE WITH A FEW 5-10 ABOVE
POSSIBLE IN THE NORMALLY COLDER LOCATIONS OF THE NE PIEDMONT.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 335 PM FRIDAY...
...WINTER WEATHER POSSIBLE EARLY TO MID NEXT WEEK...
MONDAY THROUGH TUESDAY NIGHT: UNSETTLE WEATHER IS EXPECTED NEXT WEEK
IN THE EARLY TO MIDWEEK TIME FRAME... AS A SERIES OF S/W
DISTURBANCES ARE EXPECTED TO CROSS THE REGION. THE FIRST LEAD
IMPULSE IS EXPECTED TO MOVE ACROSS THE AREA ON MONDAY.... AS S/W
ENERGY ACROSS THE CENTRAL PLAINS ON SUNDAY NIGHT SHIFTS QUICKLY EAST
AND ACROSS THE MID ATLANTIC REGION BY MONDAY NIGHT. THE LATEST ECMWF
AND NAM GENERATE SOME PRECIP OVER THE AREA ON MONDAY AS THIS SYSTEM
TRACK ACROSS THE REGION. HOWEVER... THE GFS CONTINUES TO TREND DRY.
GIVEN THE DRY AND COLD LOW LEVEL ANTECEDENT AIRMASS... THINK IF WE
DO INDEED GET SOME PRECIP IT SHOULD BE ON THE LIGHT SIDE. HOWEVER...
WITH HIGHS STRUGGLING TO REACH FREEZING ON MONDAY ANY PRECIP THAT
FALLS WILL LIKELY BE IN THE FORM OF SNOW. IN FACT THE LATEST ECMWF
STATISTICAL GUIDANCE GENERALLY KEEPS TEMPS BELOW FREEZING ALL DAY ON
MONDAY... WITH TEMPS STRUGGLING TO REACH 25 IN THE TRIAD. THUS...
*IF* PRECIP DOES DEVELOP WE COULD SEE PROBLEMS DEVELOP WITH EVEN
LIGHT AMOUNTS OF SNOWFALL MONDAY (BEST CHANCE ACROSS THE
WEST/NORTHWEST PIEDMONT). FOR NOW WILL JUST ADD A SLIGHT CHANCE OF
SNOW ACROSS MOST OF THE AREA ON MONDAY... AND LOWER HIGH TEMPS INTO
THE LOWER TO MID 30S.
THE BEST CHANCE FOR PRECIP IS EXPECTED ON MONDAY NIGHT INTO TUESDAY
NIGHT... AS A MUCH DEEPER/STRONGER TROUGH AMPLIFIES ACROSS THE DEEP
SOUTH HELPING TO SPAWN A SURFACE LOW NEAR THE NORTHER GULF COAST...
WITH THE LOW TRANSLATING NORTH AND EASTWARD AND OFF THE ATLANTIC
COAST BY TUESDAY. MEDIUM RANGE MODEL GUIDANCE HAS HAD A HARD TIME
WITH HOW MUCH MOISTURE WILL SPREAD ACROSS CENTRA NC. IT STILL
APPEARS THAT WE SHOULD BE SUFFICIENTLY COLD TO SUPPORT ALL SNOW
INITIALLY FOR THE ENTIRE AREA... (GIVEN PRECIP DOES SPREAD INTO OUR
REGION). OVER THE PAST FEW DAYS GUIDANCE HAS TRENDED TOWARDS A LOW
TRACK OFFSHORE AND NOT OVER CENTRAL NC OR TO THE WEST OF THE
MOUNTAINS. THUS.. FOR NOW WILL STICK CLOSE TO WPC POP FORECAST AND
TREND ANY P-TYPE CORRIDORS TO NARROW TRANSITION ZONES... THANKS TO
THE SINGLE SURFACE LOW OFFSHORE WITH THIS SYSTEM. AS CLASSIC WITH
THESE CASES... AS THE SURFACE HIGH SHIFTS OFFSHORE WE SHOULD SEE THE
RAIN/SNOW LINE PIVOT BACK TO THE NORTHWEST BY TUESDAY AFTERNOON
(HOWEVER BACK TO THE NORTHWEST IS STILL VERY MUCH UNCERTAIN)... WITH
A POSSIBLE PUSH OF ALL SNOW ACROSS THE ENTRIE AREA AS THE LOW BEGINS
TO LIFT OFF TO THE NORTH AND EAST OF THE AREA ON TUESDAY NIGHT.
GIVEN TIMING AND TRACK DIFFERENCES IN THE GUIDANCE IT IS VERY HARD
TO GIVE ANY EXPECTED SNOWFALL AMOUNTS ACROSS CENTRAL NC AT THIS
TIME. HOWEVER... CONFIDENCES IN INCREASING FOR A POTENTIAL WINTER
STORM TO AFFECT PORTIONS IF NOT ALL OF OUR AREA EARLY/MID NEXT
WEEK...WITH SNOWFALL ACCUMULATION POSSIBLE ACROSS (AT LEAST) PARTS
OF THE FORECAST AREA.
WEDNESDAY THROUGH FRIDAY: THE DEEPENING LOW WILL LIFT OFF TO THE
NORTHEAST OF THE AREA ON WEDNESDAY... WITH THE MAIN S/W TROUGH AXIS
CROSSING OUR REGION. THIS SHOULD RESULT IN A RETURN TO DRIER
WEATHER. HOWEVER... WITH A DEEP L/W TROUGH REMAINING ACROSS THE
EASTERN HALF OF THE COUNTRY... AND CENTERED OVER THE EAST COAST...
WE CAN EXPECT WELL BELOW NORMAL TEMPS... WITH THE POSSIBILITY OF
CLIPPER SYSTEMS MOVING ACROSS THE AREA. BOTH THE LATEST GFS AND
ECMWF SHOW ONE SUCH SYSTEM TRACKING ACROSS THE AREA... WITH THE VORT
CENTER TRACKING JUST TO THE SOUTH OF THE AREA LATE WEEK... WHICH
COULD RESULT IN SOME SNOW SHOWERS SOME TIME LATE WEEK. HOWEVER...
WILL KEEP THE FORECAST DRY FOR NOW... AS SUCH SYSTEMS ARE VERY HARD
TO TRACK ONLY A COUPLE DAYS OUT IN THE FORECAST.... LET ALONG DAYS 6
AND 7 OF THE FORECAST. WILL KEEP TEMPS IN THE 30S FOR HIGHS AND LOWS
IN THE TEENS AND 20S.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
AS OF 130 AM SATURDAY...
CALM TO OCCASIONALLY LIGHT SOUTHERLY WINDS THIS MORNING WILL BECOME
SW TO SSW AND STEADILY INCREASE AFTER 14Z...IN STRENGTHENING FLOW
BETWEEN MODIFIED ARCTIC HIGH PRESSURE ALONG AND OFFSHORE THE SE US
COAST...AND A POWERFUL ARCTIC COLD FRONT APPROACHING FROM THE
NORTHWEST. AN AREA OF ALTOCUMULUS WILL SWEEP EAST AND GRAZE MAINLY
THE NORTHERN HALF OF THE FORECAST AREA AROUND MIDDAY...AMIDST AN
OTHERWISE MOSTLY CLEAR SKY.
THE APPROACHING ARCTIC COLD FRONT WILL THEN BRING A FRIGID AND WINDY
BLAST OF AIR THROUGH CENTRAL NC THIS EVENING...AT WHICH TIME
NORTHWESTERLY WIND GUSTS OF 35 TO 45 MPH WILL BE COMMON...THE
STRONGEST OF WHICH WILL OCCUR WITHIN THE FIRST FEW HOURS OF FRONTAL
PASSAGE. A TEMPO GROUP HAS BEEN ADDED TO HIGHLIGHT THIS OCCURRENCE
AND TIMING AT THE RESPECTIVE TAF SITES. A FEW SHOWERS OR SPRINKLES
WILL ALSO ACCOMPANY THE FRONT...MOST LIKELY AT KRDU AND KRWI...THE
LATTER OF WHICH MAY EXPERIENCE A FEW WET SNOW FLAKES OR FLURRIES AS
WELL. WHILE THERE IS A SLIGHT CHANCE OF A BRIEF MVFR CEILING AND/OR
VISIBILITY RESTRICTION IN ASSOCIATION WITH ANY LOCALLY HEAVIER
PRECIPITATION...ODDS ARE THAT CONDITIONS WILL REMAIN VFR EVEN WHERE
PRECIPITATION BRIEFLY OCCURS.
OUTLOOK: WIDESPREAD SUB-VFR CONDITIONS AND PRECIPITATION...
INCLUDING SOME WINTRY...WILL BE POSSIBLE IN ASSOCIATION WITH A
COASTAL LOW MON NIGHT THROUGH TUE NIGHT...THOUGH FORECAST CONFIDENCE
REMAINS LOWER THAN AVERAGE.
&&
.FIRE WEATHER...
AS OF 330 PM FRIDAY
A STOUT SW SFC WIND WITH SUSTAINED SPEEDS 15-20 MPH
AND GUSTS AROUND 30 MPH ALONG WITH LOW RH VALUES SIGNAL THE
POTENTIAL FOR RED FLAG CONDITIONS...MAINLY ACROSS THE SOUTH HALF OF
CENTRAL NC SATURDAY AFTERNOON. IN COORDINATION WITH THE NC FORESTRY
SERVICE...A FIRE WEATHER WATCH HAS BEEN FOR SATURDAY AFTERNOON FOR
AREAS GENERALLY SOUTH OF A GOLDSBORO-SANFORD-ALBEMARLE LINE. IF
CONDITIONS EARLY SATURDAY APPEAR SIMILAR...THE WATCH WILL BE
UPGRADED TO A RED FLAG WARNING MEANING ANY FIRES THAT OCCUR MAY
QUICKLY BURN OUT OF CONTROL.
OVER THE REMAINDER OF CENTRAL NC...AN INCREASE FIRE DANGER STATEMENT
WILL BE IN EFFECT AS PARAMETERS WILL BE JUST SHY OF RED FLAG
CRITERIA.
ESSENTIALLY...ANY OUTDOOR BURNING SHOULD BE DELAYED UNTIL LESS
VOLATILE CONDITIONS OCCUR.
&&
.CLIMATE...
THE FOLLOWING ARE TEMPERATURE RECORDS FOR FEBRUARY 15 AND 16:
RECORD LOWS
GSO RDU FAY
FEBRUARY 15: 6 IN 1943 6 IN 1899 12 IN 1943
FEBRUARY 16: 8 IN 1905 11 IN 1905 17 IN 1991
RECORD LOW MAXIMUMS
GSO RDU FAY
FEBRUARY 15: 28 IN 1943 29 IN 1943 36 IN 1965
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
FIRE WEATHER WATCH SATURDAY AFTERNOON FOR NCZ042-73>078-083>086-088-
089.
&&
$$
SYNOPSIS...RAH
NEAR TERM...ELLIS/WSS
SHORT TERM...WSS
LONG TERM...BSD
AVIATION...RAH
FIRE WEATHER...WSS
CLIMATE...RAH
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
447 PM EST SAT FEB 14 2015
.SYNOPSIS...
AN ARCTIC COLD FRONT WILL SWEEP THROUGH THE COMMONWEALTH THIS
AFTERNOON AND EVENING. THE COLDEST AIR OF THE SEASON WILL BE WITH
US SUNDAY INTO EARLY MONDAY ALONG WITH DANGEROUSLY LOW WIND CHILLS
OF 20 TO 35 BELOW ZERO. THE NEXT CHANCE FOR SNOW WILL BE AROUND
MID WEEK AS AN AREA OF LOW PRESSURE MOVES NORTHEAST FROM THE GULF
COAST STATES.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
SENT A QUICK UPDATE TO COVER INCLUDING THE SOUTHERN ZONES IN A
WINTER WEATHER ADVISORY.
MESO ANAL INDICATES THE ARCTIC COLD FRONT AT MID DAY IS ENTERING
FAR NWRN PA. RADAR SHOWS A DEVELOPING LINE OF SNOW SHOWERS AND
SQUALLS ALONG THE SHARP CONVERGENCE ZONE. LOCALLY WE HAVE A
WIDESPREAD AREA OF FAIRLY LIGHT SNOW BEING FORCED BY STRONG WARM
ADVECTION AHEAD OF THE APPROACHING FRONT. HIGHER ELEVATIONS TO OUR
WEST HAVE EXPERIENCED SMALL ACCUMS OF AN INCH OR 2...WHILE JUST
EAST OF THE HIGHER TERRAIN AMOUNTS HAVE BEEN OF THE NUISANCE OR
DUSTING VARIETY.
HIGH RES MODELS CONTINUE TO INDICATE A LINE OF SNOW SQUALLS NOW
ENTERING NW PORTIONS OF THE REGION...PROGRESSING OFF TO THE EAST
THEREAFTER. RAP DEVELOPS SOME IMPRESSIVE INSTABILITY FOR MID
FEBRUARY...WITH STEEPENING LOW-MID LEVEL LAPSE RATES AND EVEN
COOKING UP A COUPLE OF HUNDRED JOULES OF CAPE IN RESPONSE TO
RAPIDLY FALLING HEIGHTS AND TEMPS ALOFT.
CURRENT TIMING HAS THE COLD FRONT/SQUALL LINE MOVING THROUGH
BRADFORD AROUND 20Z/3PM...MOVING EAST TO A LINE FROM JOHNSTOWN
THROUGH CLEARFIELD UP INTO COUDERSPORT AROUND 21Z/4PM...AND INTO
RENOVO-STATE COLLEGE-ALTOONA BY 22Z/5PM. EAST OF THE CENTRAL
MOUNTAINS THE HRRR TRIES TO MAKE THE SQUALL LINE MORE
DISORGANIZED SO TIMING MAY BE MORE NEBULOUS.
I WOULD NOT RULE OUT A LITTLE THUNDER SNOW AS THE FORCING LOOKS
ESPECIALLY ROBUST FOR THE TIME OF YEAR.
TEMPS IN THE 20S TO LOWER 30S AHEAD OF THE FRONT AND THE
POTENTIAL FOR WET/PRE-TREATED ROADS FROM ANY LIGHT SNOW AHEAD OF
THE FRONT...WILL LEAD TO A DANGEROUS...FLASH FREEZE SETUP AS THE
ARCTIC FRONT PLOWS EAST ACROSS THE STATE ACCOMPANIED BY ONE OR TWO
DISTINCT NORTH/SOUTH BANDS OF BLINDING SNOW SQUALLS...SHARPLY
FALLING TEMPS...AND WIND GUSTS OF 35-45 MPH. HAZARDOUS INTERSTATE
TRAVEL CONDITIONS ARE EXPECTED TO DEVELOP FROM WEST TO EAST THIS
AFTERNOON.
A WINTER WX ADVISORY COVERS MUCH OF CENTRAL PA THROUGH 12Z SUNDAY
AS MODEL BLENDED QPF COMBINED WITH SLR/S OF CLOSE TO 20/1 SUPPORT
A GENERAL 2-4 INCH SNOWFALL TODAY AND TONIGHT FROM THE ONE-TWO
PUNCH OF THE ARCTIC FRONT...THEN PERIODS OF SNOW/SNOW SHOWERS
ASSOCIATED WITH THE PASSAGE OF THE SE DIGGING CLOSED UPPER LOW.
THE HIGHER SNOWFALL AMOUNTS WILL BE CONFINED TO MAINLY THE NW
MTNS...WRN POCONOS AND ENDLESS MTNS OF NEPA...AND THE LAUREL
HIGHLANDS IN THE SOUTHWEST.
EVEN THOSE LOCATIONS THAT FALL SHORT OF ADVISORY CRITERIA SNOW
WILL HAVE TO CONTEND WITH AREAS OF BLOWING/DRIFTING SNOW BEHIND
THE COLD FRONT LATE TODAY AND TONIGHT. BUFKIT SOUNDINGS SUPPORT
FREQUENT GUSTS IN THE 35-40KT RANGE IN WAKE OF FRONT ACROSS MUCH
OF THE CENTRAL RIDGE AND VALLEY REGION...LASTING THRU TONIGHT.
EVEN HIGHER GUSTS...OCNLY UP TO BETWEEN 45-50 KTS APPEAR LIKELY
ACROSS THE REGION NEAR AND TO THE SE OF I-81...SO THE HIGH WIND
WATCH TRANSITIONED TO A HIGH WIND WARNING THERE. THE HIGH WIND
WARNING AND WIND ADVISORY RUNS THROUGH NOON SUNDAY.
THE LOW SHOULD BE QUICKLY RE-DEVELOPING OVER EASTERN PA OR OVER
THE COASTAL WATERS BY EVENING...WITH THE LOCAL AREA TRANSITIONING
INTO A POST COLD FRONTAL FLOW PATTERN. WITH THE LOW EXPECTED TO
BE DEEPENING RAPIDLY...STRONG GUSTY WINDS WILL DEVELOP AND
CONTINUE INTO THE OVERNIGHT CAUSING WIND CHILLS TO DIP TO
DANGEROUSLY LOW LEVELS OVER THE ENTIRE FCST AREA. AFTER
COLLABORATION WITH SURROUNDING WFOS WE DECIDED TO ISSUE A WIND
CHILL WARNING FOR THE ENTIRE CWA TONIGHT THROUGH MONDAY MORNING.
ACTUAL AIR TEMPERATURES WILL PLUMMET TONIGHT TO BETWEEN 5 AND 15
DEGREES BELOW ZERO ACROSS THE NORTHWEST MOUNTAINS AND LAUREL
HIGHLANDS...AND SETTLE BETWEEN ZERO AND 5 ABOVE THROUGHOUT THE
LARGER METRO AREAS OF THE LOWER SUSQUEHANNA VALLEY.
&&
.SHORT TERM /SUNDAY/...
SHALLOW STRATO CU CLOUDS CLOUDS SHOULD BREAK ALONG AND TO THE SE
OF THE I-99/I-80/RT 220 CORRIDOR SUNDAY AS HIGH PRESSURE BUILDS
EAST FROM THE OHIO VALLEY LATE IN THE DAY. SCATTERED FLURRIES WILL
OCCUR SUNDAY AFTERNOON ACROSS THE CENTRAL ZONES...WHILE THE NW
MTNS AND LAURELS COULD SEE LOCALLY UP TO ANOTHER ADDITIONAL
COATING TO ONE INCH FROM SCATTERED SNOW SHOWERS.
HIGH TEMPERATURES WILL STRUGGLE TO REACH 5 BELOW ZERO ACROSS THE
NORTHWEST MOUNTAINS...AND WILL ONLY MAKE IT TO 10 TO 12 DEGREES
ABOVE ZERO ACROSS THE LOWER SUSQUEHANNA VALLEY.
&&
.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
VERY COLD AIR WILL CONTINUE TO IMPACT THE REGION THROUGH AT LEAST
THE NEXT WEEK AS STRONG RIDGE OVER WESTERN U.S. CONTINUES TO
DIRECT POLAR AIR INTO THE EASTERN U.S. VIA PERSISTENT TROUGH.
RECORD LOWS FOR THE DATE EARLY MONDAY APPEAR LIKELY. LOWS EARLY
MONDAY MORNING UNDER CLEAR TO PARTLY CLOUDY SKIES WITH DIMINISHING
WIND WILL EASILY AVERAGE 10-15 BELOW ZERO ACROSS THE NRN AND
WESTERN MTNS...AND 5-10 BELOW ZERO THROUGHOUT MUCH OF THE CENTRAL
RIDGE AND VALLEY REGION. SOME PROTECTED VALLEYS ACROSS THE NORTH
COULD DIP TO NEAR 25 BELOW BETWEEN 09-12Z MONDAY. SURFACE HIGH
WILL PROPAGATE ACROSS CENTRAL PA MONDAY AND MONDAY NIGHT...MOVING
OFFSHORE ON TUESDAY.
STILL AT LEAST SOME POTENTIAL INDICATED FOR SOME PHASING OF
NORTHERN AND SOUTHERN STREAM WAVES OVER THE GULF COAST AND
SOUTHEASTERN U.S. BY LATER TUE INTO WED...BRINGING THE CHANCE OF
SNOW TO THE REGION. HOWEVER...AGAIN TODAY MODEL TRENDS OVER CONTINUE
TO LEND CREDENCE TOWARD A MORE SUPPRESSED/FLATTER SOUTHERN STREAM
SYSTEM WITH THE ARCTIC AIR DOMINATING THE GREAT LAKES REGION AND
NE U.S. AND THE BULK OF ANY STEADIER/STRATIFORM PRECIP STAYING
CONFINED TO THE SE U.S. AND MAYBE THE VIRGINIAS.
YET ANOTHER SURGE OF EXTREMELY COLD AIR RIDES IN ON PERSISTENT
NORTHWEST LATE NEXT WEEK...AS A MASSIVE RIDGE OF SURFACE HIGH
PRESSURE COVERS THE EASTERN HALF OF THE CONUS.
&&
.AVIATION /22Z SATURDAY THROUGH THURSDAY/...
CURRENT FCST LOOKS GOOD. MINOR ADJUSTMENTS MADE TO THE 21Z TAFS.
EVEN SOME THUNDER WITH THE SNOW SQUALLS.
EARLIER DISCUSSION BELOW.
THE ARCTIC COLD FRONT IS ENTERING NWRN PA AS OF MID DAY....
A SFC LOW ASSOCIATED WITH THE COLD FRONT TRACK ESE ACROSS THE NRN
MID ATLANTIC STATES THIS AFTERNOON BEFORE RAPIDLY INTENSIFYING
JUST OFFSHORE SRN NEW ENGLAND TONIGHT INTO EARLY SUNDAY.
THE ARCTIC COLD FRONT WILL MOVE THROUGH THE FLYING AREA AND BE
THE FOCUS FOR LOCALLY HEAVY SNOW SQUALLS THIS AFTERNOON AND
EVENING...WITH AN AREA OF PRE-FRONTAL LIGHT SNOW AND MVFR/IFR
CONDITIONS ALREADY IMPACTING THE WRN 1/3 TO 1/2 OF THE AIRSPACE.
OVERALL EXPECT PREVAILING IFR ACROSS THE HIGHER ELEVATION SITES
FROM JST UP THROUGH BFD. CENTRAL TERMINALS WILL SEE PERIODS OF
IFR BUT MVFR WILL MORE LIKELY BE THE PREVAILING FLIGHT CAT.
PREVAILING VFR WITH PERIODS OF MVFR CAN BE EXPECTED AT THE SERN
SITES. USED 1HR TEMPO TO SHOW BEST TIME WINDOW FOR HEAVY SNOW AND
REDUCED CONDITIONS ASSOCIATED WITH EXPECTED SNOW SQUALL
ACTIVITY...WITH A SHARP DROP IN VIS TO 1/2 MILE OR LESS. WIND WILL
BECOME THE MAIN CONCERN LATER TONIGHT INTO EARLY SUNDAY WITH
PEAK GUSTS IN THE 35-45KT RANGE FROM AROUND 300 DEGREES. MVFR/IFR
IN OCNL SHSN WILL LINGER OVER THE WRN TERMINALS INTO SUNDAY WITH
GRADUAL IMPROVEMENT EXPECTED DURING THE DAY. ELSEWHERE LOOK FOR A
RETURN TO LOW VFR WITH CIGS BTWN 3000-5000`.
OUTLOOK...
MON-TUE...VFR/NO SIG WX.
WED-THU...MVFR/IFR SHSN WEST. VFR/MVFR EAST.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 7 AM EST SUNDAY FOR PAZ004>006-
010>012-017>019-024>028-033>037-041-042-045-046-049>053-
056>059-063>066.
WIND ADVISORY UNTIL NOON EST SUNDAY FOR PAZ012-017>019-024>028-
033>035-037-041-042-045-046-049>053.
WIND CHILL WARNING FROM MIDNIGHT TONIGHT TO 10 AM EST MONDAY
FOR PAZ012-018-019-025>028-034>037-041-042-045-046-049>053-
056>059-063>066.
WIND CHILL WARNING UNTIL 10 AM EST MONDAY FOR PAZ004>006-010-
011-017-024-033.
HIGH WIND WARNING UNTIL NOON EST SUNDAY FOR PAZ036-056>059-
063>066.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...LA CORTE
SHORT TERM...LA CORTE
LONG TERM...LAMBERT/GARTNER
AVIATION...LA CORTE/MARTIN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
400 PM EST SAT FEB 14 2015
.SYNOPSIS...
AN ARCTIC COLD FRONT WILL SWEEP THROUGH THE COMMONWEALTH THIS
AFTERNOON AND EVENING. THE COLDEST AIR OF THE SEASON WILL BE WITH
US SUNDAY INTO EARLY MONDAY ALONG WITH DANGEROUSLY LOW WIND CHILLS
OF 20 TO 35 BELOW ZERO. THE NEXT CHANCE FOR SNOW WILL BE AROUND
MID WEEK AS AN AREA OF LOW PRESSURE MOVES NORTHEAST FROM THE GULF
COAST STATES.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
SENT A QUICK UPDATE TO COVER INCLUDING THE SOUTHERN ZONES IN A
WINTER WEATHER ADVISORY.
MESO ANAL INDICATES THE ARCTIC COLD FRONT
AT MID DAY IS ENTERING FAR NWRN PA. RADAR SHOWS A DEVELOPING LINE
OF SNOW SHOWERS AND SQUALLS ALONG THE SHARP CONVERGENCE ZONE.
LOCALLY WE HAVE A WIDESPREAD AREA OF FAIRLY LIGHT SNOW BEING
FORCED BY STRONG WARM ADVECTION AHEAD OF THE APPROACHING FRONT.
HIGHER ELEVATIONS TO OUR WEST HAVE EXPERIENCED SMALL ACCUMS OF AN
INCH OR 2...WHILE JUST EAST OF THE HIGHER TERRAIN AMOUNTS HAVE
BEEN OF THE NUISANCE OR DUSTING VARIETY.
HIGH RES MODELS CONTINUE TO INDICATE A LINE OF SNOW SQUALLS NOW
ENTERING NW PORTIONS OF THE REGION...PROGRESSING OFF TO THE EAST
THEREAFTER. RAP DEVELOPS SOME IMPRESSIVE INSTABILITY FOR MID
FEBRUARY...WITH STEEPENING LOW-MID LEVEL LAPSE RATES AND EVEN
COOKING UP A COUPLE OF HUNDRED JOULES OF CAPE IN RESPONSE TO
RAPIDLY FALLING HEIGHTS AND TEMPS ALOFT.
CURRENT TIMING HAS THE COLD FRONT/SQUALL LINE MOVING THROUGH
BRADFORD AROUND 20Z/3PM...MOVING EAST TO A LINE FROM JOHNSTOWN
THROUGH CLEARFIELD UP INTO COUDERSPORT AROUND 21Z/4PM...AND INTO
RENOVO-STATE COLLEGE-ALTOONA BY 22Z/5PM. EAST OF THE CENTRAL
MOUNTAINS THE HRRR TRIES TO MAKE THE SQUALL LINE MORE
DISORGANIZED SO TIMING MAY BE MORE NEBULOUS.
I WOULD NOT RULE OUT A LITTLE THUNDER SNOW AS THE FORCING LOOKS
ESPECIALLY ROBUST FOR THE TIME OF YEAR.
TEMPS IN THE 20S TO LOWER 30S AHEAD OF THE FRONT AND THE
POTENTIAL FOR WET/PRE-TREATED ROADS FROM ANY LIGHT SNOW AHEAD OF
THE FRONT...WILL LEAD TO A DANGEROUS...FLASH FREEZE SETUP AS THE
ARCTIC FRONT PLOWS EAST ACROSS THE STATE ACCOMPANIED BY ONE OR TWO
DISTINCT NORTH/SOUTH BANDS OF BLINDING SNOW SQUALLS...SHARPLY
FALLING TEMPS...AND WIND GUSTS OF 35-45 MPH. HAZARDOUS INTERSTATE
TRAVEL CONDITIONS ARE EXPECTED TO DEVELOP FROM WEST TO EAST THIS
AFTERNOON.
A WINTER WX ADVISORY COVERS MUCH OF CENTRAL PA THROUGH 12Z SUNDAY
AS MODEL BLENDED QPF COMBINED WITH SLR/S OF CLOSE TO 20/1 SUPPORT
A GENERAL 2-4 INCH SNOWFALL TODAY AND TONIGHT FROM THE ONE-TWO
PUNCH OF THE ARCTIC FRONT...THEN PERIODS OF SNOW/SNOW SHOWERS
ASSOCIATED WITH THE PASSAGE OF THE SE DIGGING CLOSED UPPER LOW.
THE HIGHER SNOWFALL AMOUNTS WILL BE CONFINED TO MAINLY THE NW
MTNS...WRN POCONOS AND ENDLESS MTNS OF NEPA...AND THE LAUREL
HIGHLANDS IN THE SOUTHWEST.
EVEN THOSE LOCATIONS THAT FALL SHORT OF ADVISORY CRITERIA SNOW
WILL HAVE TO CONTEND WITH AREAS OF BLOWING/DRIFTING SNOW BEHIND
THE COLD FRONT LATE TODAY AND TONIGHT. BUFKIT SOUNDINGS SUPPORT
FREQUENT GUSTS IN THE 35-40KT RANGE IN WAKE OF FRONT ACROSS MUCH
OF THE CENTRAL RIDGE AND VALLEY REGION...LASTING THRU TONIGHT.
EVEN HIGHER GUSTS...OCNLY UP TO BETWEEN 45-50 KTS APPEAR LIKELY
ACROSS THE REGION NEAR AND TO THE SE OF I-81...SO THE HIGH WIND
WATCH TRANSITIONED TO A HIGH WIND WARNING THERE. THE HIGH WIND
WARNING AND WIND ADVISORY RUNS THROUGH NOON SUNDAY.
THE LOW SHOULD BE QUICKLY RE-DEVELOPING OVER EASTERN PA OR OVER
THE COASTAL WATERS BY EVENING...WITH THE LOCAL AREA TRANSITIONING
INTO A POST COLD FRONTAL FLOW PATTERN. WITH THE LOW EXPECTED TO
BE DEEPENING RAPIDLY...STRONG GUSTY WINDS WILL DEVELOP AND
CONTINUE INTO THE OVERNIGHT CAUSING WIND CHILLS TO DIP TO
DANGEROUSLY LOW LEVELS OVER THE ENTIRE FCST AREA. AFTER
COLLABORATION WITH SURROUNDING WFOS WE DECIDED TO ISSUE A WIND
CHILL WARNING FOR THE ENTIRE CWA TONIGHT THROUGH MONDAY MORNING.
ACTUAL AIR TEMPERATURES WILL PLUMMET TONIGHT TO BETWEEN 5 AND 15
DEGREES BELOW ZERO ACROSS THE NORTHWEST MOUNTAINS AND LAUREL
HIGHLANDS...AND SETTLE BETWEEN ZERO AND 5 ABOVE THROUGHOUT THE
LARGER METRO AREAS OF THE LOWER SUSQUEHANNA VALLEY.
&&
.SHORT TERM /SUNDAY/...
SHALLOW STRATO CU CLOUDS CLOUDS SHOULD BREAK ALONG AND TO THE SE
OF THE I-99/I-80/RT 220 CORRIDOR SUNDAY AS HIGH PRESSURE BUILDS
EAST FROM THE OHIO VALLEY LATE IN THE DAY. SCATTERED FLURRIES WILL
OCCUR SUNDAY AFTERNOON ACROSS THE CENTRAL ZONES...WHILE THE NW
MTNS AND LAURELS COULD SEE LOCALLY UP TO ANOTHER ADDITIONAL
COATING TO ONE INCH FROM SCATTERED SNOW SHOWERS.
HIGH TEMPERATURES WILL STRUGGLE TO REACH 5 BELOW ZERO ACROSS THE
NORTHWEST MOUNTAINS...AND WILL ONLY MAKE IT TO 10 TO 12 DEGREES
ABOVE ZERO ACROSS THE LOWER SUSQUEHANNA VALLEY.
&&
.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
VERY COLD AIR WILL CONTINUE TO IMPACT THE REGION THROUGH AT LEAST
THE NEXT WEEK AS STRONG RIDGE OVER WESTERN U.S. CONTINUES TO
DIRECT POLAR AIR INTO THE EASTERN U.S. VIA PERSISTENT TROUGH.
RECORD LOWS FOR THE DATE EARLY MONDAY APPEAR LIKELY. LOWS EARLY
MONDAY MORNING UNDER CLEAR TO PARTLY CLOUDY SKIES WITH DIMINISHING
WIND WILL EASILY AVERAGE 10-15 BELOW ZERO ACROSS THE NRN AND
WESTERN MTNS...AND 5-10 BELOW ZERO THROUGHOUT MUCH OF THE CENTRAL
RIDGE AND VALLEY REGION. SOME PROTECTED VALLEYS ACROSS THE NORTH
COULD DIP TO NEAR 25 BELOW BETWEEN 09-12Z MONDAY. SURFACE HIGH
WILL PROPAGATE ACROSS CENTRAL PA MONDAY AND MONDAY NIGHT...MOVING
OFFSHORE ON TUESDAY.
STILL AT LEAST SOME POTENTIAL INDICATED FOR SOME PHASING OF
NORTHERN AND SOUTHERN STREAM WAVES OVER THE GULF COAST AND
SOUTHEASTERN U.S. BY LATER TUE INTO WED...BRINGING THE CHANCE OF
SNOW TO THE REGION. HOWEVER...AGAIN TODAY MODEL TRENDS OVER CONTINUE
TO LEND CREDENCE TOWARD A MORE SUPPRESSED/FLATTER SOUTHERN STREAM
SYSTEM WITH THE ARCTIC AIR DOMINATING THE GREAT LAKES REGION AND
NE U.S. AND THE BULK OF ANY STEADIER/STRATIFORM PRECIP STAYING
CONFINED TO THE SE U.S. AND MAYBE THE VIRGINIAS.
YET ANOTHER SURGE OF EXTREMELY COLD AIR RIDES IN ON PERSISTENT
NORTHWEST LATE NEXT WEEK...AS A MASSIVE RIDGE OF SURFACE HIGH
PRESSURE COVERS THE EASTERN HALF OF THE CONUS.
&&
.AVIATION /21Z SATURDAY THROUGH THURSDAY/...
THE ARCTIC COLD FRONT IS ENTERING NWRN PA AS OF MID DAY....
A SFC LOW ASSOCIATED WITH THE COLD FRONT TRACK ESE ACROSS THE NRN
MID ATLANTIC STATES THIS AFTERNOON BEFORE RAPIDLY INTENSIFYING
JUST OFFSHORE SRN NEW ENGLAND TONIGHT INTO EARLY SUNDAY.
THE ARCTIC COLD FRONT WILL MOVE THROUGH THE FLYING AREA AND BE
THE FOCUS FOR LOCALLY HEAVY SNOW SQUALLS THIS AFTERNOON AND
EVENING...WITH AN AREA OF PRE-FRONTAL LIGHT SNOW AND MVFR/IFR
CONDITIONS ALREADY IMPACTING THE WRN 1/3 TO 1/2 OF THE AIRSPACE.
OVERALL EXPECT PREVAILING IFR ACROSS THE HIGHER ELEVATION SITES
FROM JST UP THROUGH BFD. CENTRAL TERMINALS WILL SEE PERIODS OF
IFR BUT MVFR WILL MORE LIKELY BE THE PREVAILING FLIGHT CAT.
PREVAILING VFR WITH PERIODS OF MVFR CAN BE EXPECTED AT THE SERN
SITES. USED 1HR TEMPO TO SHOW BEST TIME WINDOW FOR HEAVY SNOW AND
REDUCED CONDITIONS ASSOCIATED WITH EXPECTED SNOW SQUALL
ACTIVITY...WITH A SHARP DROP IN VIS TO 1/2 MILE OR LESS. WIND WILL
BECOME THE MAIN CONCERN LATER TONIGHT INTO EARLY SUNDAY WITH
PEAK GUSTS IN THE 35-45KT RANGE FROM AROUND 300 DEGREES. MVFR/IFR
IN OCNL SHSN WILL LINGER OVER THE WRN TERMINALS INTO SUNDAY WITH
GRADUAL IMPROVEMENT EXPECTED DURING THE DAY. ELSEWHERE LOOK FOR A
RETURN TO LOW VFR WITH CIGS BTWN 3000-5000`.
OUTLOOK...
MON-TUE...VFR/NO SIG WX.
WED-THU...MVFR/IFR SHSN WEST. VFR/MVFR EAST.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 7 AM EST SUNDAY FOR PAZ004>006-
010>012-017>019-024>028-033>037-041-042-045-046-049>053-
056>059-063>066.
WIND ADVISORY FROM 7 PM THIS EVENING TO NOON EST SUNDAY FOR
PAZ012-017>019-024>028-033>035-037-041-042-045-046-049>053.
WIND CHILL WARNING FROM MIDNIGHT TONIGHT TO 10 AM EST MONDAY
FOR PAZ012-018-019-025>028-034>037-041-042-045-046-049>053-
056>059-063>066.
WIND CHILL WARNING FROM 7 PM THIS EVENING TO 10 AM EST MONDAY
FOR PAZ004>006-010-011-017-024-033.
HIGH WIND WARNING FROM 7 PM THIS EVENING TO NOON EST SUNDAY
FOR PAZ036-056>059-063>066.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...LA CORTE
SHORT TERM...LA CORTE
LONG TERM...LAMBERT/GARTNER
AVIATION...LA CORTE
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
226 PM EST SAT FEB 14 2015
.SYNOPSIS...
AN ARCTIC COLD FRONT WILL SWEEP THROUGH THE COMMONWEALTH THIS
AFTERNOON AND EVENING. THE COLDEST AIR OF THE SEASON WILL BE WITH
US SUNDAY INTO EARLY MONDAY ALONG WITH DANGEROUSLY LOW WIND CHILLS
OF 20 TO 35 BELOW ZERO. THE NEXT CHANCE FOR SNOW WILL BE AROUND
MID WEEK AS AN AREA OF LOW PRESSURE MOVES NORTHEAST FROM THE GULF
COAST STATES.
&&
.NEAR TERM /THROUGH TONIGHT/...
SENT A QUICK UPDATE TO COVER INCLUDING THE SOUTHERN ZONES IN A
WINTER WEATHER ADVISORY.
MESO ANAL INDICATES THE ARCTIC COLD FRONT
AT MID DAY IS ENTERING FAR NWRN PA. RADAR SHOWS A DEVELOPING LINE
OF SNOW SHOWERS AND SQUALLS ALONG THE SHARP CONVERGENCE ZONE.
LOCALLY WE HAVE A WIDESPREAD AREA OF FAIRLY LIGHT SNOW BEING
FORCED BY STRONG WARM ADVECTION AHEAD OF THE APPROACHING FRONT.
HIGHER ELEVATIONS TO OUR WEST HAVE EXPERIENCED SMALL ACCUMS OF AN
INCH OR 2...WHILE JUST EAST OF THE HIGHER TERRAIN AMOUNTS HAVE
BEEN OF THE NUISANCE OR DUSTING VARIETY.
HIGH RES MODELS CONTINUE TO INDICATE A LINE OF SNOW SQUALLS NOW
ENTERING NW PORTIONS OF THE REGION...PROGRESSING OFF TO THE EAST
THEREAFTER. RAP DEVELOPS SOME IMPRESSIVE INSTABILITY FOR MID
FEBRUARY...WITH STEEPENING LOW-MID LEVEL LAPSE RATES AND EVEN
COOKING UP A COUPLE OF HUNDRED JOULES OF CAPE IN RESPONSE TO
RAPIDLY FALLING HEIGHTS AND TEMPS ALOFT.
CURRENT TIMING HAS THE COLD FRONT/SQUALL LINE MOVING THROUGH
BRADFORD AROUND 20Z/3PM...MOVING EAST TO A LINE FROM JOHNSTOWN
THROUGH CLEARFIELD UP INTO COUDERSPORT AROUND 21Z/4PM...AND INTO
RENOVO-STATE COLLEGE-ALTOONA BY 22Z/5PM. EAST OF THE CENTRAL
MOUNTAINS THE HRRR TRIES TO MAKE THE SQUALL LINE MORE
DISORGANIZED SO TIMING MAY BE MORE NEBULOUS.
I WOULD NOT RULE OUT A LITTLE THUNDER SNOW AS THE FORCING LOOKS
ESPECIALLY ROBUST FOR THE TIME OF YEAR.
TEMPS IN THE 20S TO LOWER 30S AHEAD OF THE FRONT AND THE
POTENTIAL FOR WET/PRE-TREATED ROADS FROM ANY LIGHT SNOW AHEAD OF
THE FRONT...WILL LEAD TO A DANGEROUS...FLASH FREEZE SETUP AS THE
ARCTIC FRONT PLOWS EAST ACROSS THE STATE ACCOMPANIED BY ONE OR TWO
DISTINCT NORTH/SOUTH BANDS OF BLINDING SNOW SQUALLS...SHARPLY
FALLING TEMPS...AND WIND GUSTS OF 35-45 MPH. HAZARDOUS INTERSTATE
TRAVEL CONDITIONS ARE EXPECTED TO DEVELOP FROM WEST TO EAST THIS
AFTERNOON.
A WINTER WX ADVISORY COVERS MUCH OF CENTRAL PA THROUGH 12Z SUNDAY
AS MODEL BLENDED QPF COMBINED WITH SLR/S OF CLOSE TO 20/1 SUPPORT
A GENERAL 2-4 INCH SNOWFALL TODAY AND TONIGHT FROM THE ONE-TWO
PUNCH OF THE ARCTIC FRONT...THEN PERIODS OF SNOW/SNOW SHOWERS
ASSOCIATED WITH THE PASSAGE OF THE SE DIGGING CLOSED UPPER LOW.
THE HIGHER SNOWFALL AMOUNTS WILL BE CONFINED TO MAINLY THE NW
MTNS...WRN POCONOS AND ENDLESS MTNS OF NEPA...AND THE LAUREL
HIGHLANDS IN THE SOUTHWEST.
EVEN THOSE LOCATIONS THAT FALL SHORT OF ADVISORY CRITERIA SNOW
WILL HAVE TO CONTEND WITH AREAS OF BLOWING/DRIFTING SNOW BEHIND
THE COLD FRONT LATE TODAY AND TONIGHT. BUFKIT SOUNDINGS SUPPORT
FREQUENT GUSTS IN THE 35-40KT RANGE IN WAKE OF FRONT ACROSS MUCH
OF THE CENTRAL RIDGE AND VALLEY REGION...LASTING THRU TONIGHT.
EVEN HIGHER GUSTS...OCNLY UP TO BETWEEN 45-50 KTS APPEAR LIKELY
ACROSS THE REGION NEAR AND TO THE SE OF I-81...SO THE HIGH WIND
WATCH TRANSITIONED TO A HIGH WIND WARNING THERE. THE HIGH WIND
WARNING AND WIND ADVISORY RUNS THROUGH NOON SUNDAY.
THE LOW SHOULD BE QUICKLY RE-DEVELOPING OVER EASTERN PA OR OVER
THE COASTAL WATERS BY EVENING...WITH THE LOCAL AREA TRANSITIONING
INTO A POST COLD FRONTAL FLOW PATTERN. WITH THE LOW EXPECTED TO
BE DEEPENING RAPIDLY...STRONG GUSTY WINDS WILL DEVELOP AND
CONTINUE INTO THE OVERNIGHT CAUSING WIND CHILLS TO DIP TO
DANGEROUSLY LOW LEVELS OVER THE ENTIRE FCST AREA. AFTER
COLLABORATION WITH SURROUNDING WFOS WE DECIDED TO ISSUE A WIND
CHILL WARNING FOR THE ENTIRE CWA TONIGHT THROUGH MONDAY MORNING.
ACTUAL AIR TEMPERATURES WILL PLUMMET TONIGHT TO BETWEEN 5 AND 15
DEGREES BELOW ZERO ACROSS THE NORTHWEST MOUNTAINS AND LAUREL
HIGHLANDS...AND SETTLE BETWEEN ZERO AND 5 ABOVE THROUGHOUT THE
LARGER METRO AREAS OF THE LOWER SUSQUEHANNA VALLEY.
&&
.SHORT TERM /SUNDAY/...
SHALLOW STRATO CU CLOUDS CLOUDS SHOULD BREAK ALONG AND TO THE SE
OF THE I-99/I-80/RT 220 CORRIDOR SUNDAY AS HIGH PRESSURE BUILDS
EAST FROM THE OHIO VALLEY LATE IN THE DAY. SCATTERED FLURRIES WILL
OCCUR SUNDAY AFTERNOON ACROSS THE CENTRAL ZONES...WHILE THE NW
MTNS AND LAURELS COULD SEE LOCALLY UP TO ANOTHER ADDITIONAL
COATING TO ONE INCH FROM SCATTERED SNOW SHOWERS.
HIGH TEMPERATURES WILL STRUGGLE TO REACH 5 BELOW ZERO ACROSS THE
NORTHWEST MOUNTAINS...AND WILL ONLY MAKE IT TO 10 TO 12 DEGREES
ABOVE ZERO ACROSS THE LOWER SUSQUEHANNA VALLEY.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
VERY COLD AIR WILL CONTINUE TO IMPACT THE REGION THROUGH AT LEAST
THE NEXT WEEK AS STRONG RIDGE OVER WESTERN U.S. CONTINUES TO
DIRECT POLAR AIR INTO THE EASTERN U.S. VIA PERSISTENT TROUGH.
ALTHOUGH WINDS WILL GRADUALLY RELAX INTO MON...COMBINATION OF
COLD TEMPS AND WIND JUSTIFIES THE WIND CHILL WATCH CURRENTLY IN
EFFECT THROUGH THAT 36HR PERIOD. THIS WILL LIKELY NEED TO BE
UPGRADED TO A WARNING AS EVENT WINDOW APPROACHES. WILL ALSO NEED
TO STRONGLY CONSIDER A WIND ADVISORY ESP FOR HIGHER TERRAIN AND
NW-SE ALIGNED VALLEYS ACROSS SOUTHERN AREAS SAT NIGHT INTO EARLY
SUN WITH PEAK WIND GUSTS IN THE 40-50 MPH RANGE.
RECORD LOWS FOR THE DATE EARLY MONDAY APPEAR LIKELY. LOWS EARLY
MONDAY MORNING UNDER CLEAR TO PARTLY CLOUDY SKIES WITH DIMINISHING
WIND WILL EASILY AVERAGE 10-15 BELOW ZERO ACROSS THE NRN AND
WESTERN MTNS...AND 5-10 BELOW ZERO THROUGHOUT MUCH OF THE CENTRAL
RIDGE AND VALLEY REGION. SOME PROTECTED VALLEYS ACROSS THE NORTH
COULD DIP TO NEAR 25 BELOW BETWEEN 09-12Z MONDAY. SURFACE HIGH
WILL PROPAGATE ACROSS CENTRAL PA MONDAY AND MONDAY NIGHT...MOVING
OFFSHORE ON TUESDAY.
STILL AT LEAST SOME POTENTIAL INDICATED FOR SOME PHASING OF
NORTHERN AND SOUTHERN STREAM WAVES OVER THE GULF COAST AND
SOUTHEASTERN U.S. BY LATER TUE INTO WED...BRINGING THE CHANCE OF
SNOW TO THE REGION. HOWEVER...MODEL TRENDS OVER PREVIOUS FEW DAYS
CONTINUE TO LEND CREDENCE TOWARD A MORE SUPPRESSED/FLATTER
SOUTHERN STREAM SYSTEM WITH THE ARCTIC AIR DOMINATING THE GREAT
LAKES REGION AND NE U.S. AND THE BULK OF ANY STEADIER/STRATIFORM
PRECIP STAYING CONFINED TO THE SE U.S. AND MAYBE THE VIRGINIAS.
YET ANOTHER SURGE OF EXTREMELY COLD AIR RIDES IN ON PERSISTENT
NORTHWEST LATE NEXT WEEK...AS A MASSIVE RIDGE OF SURFACE HIGH
PRESSURE COVERS THE EASTERN HALF OF THE CONUS.
&&
.AVIATION /20Z SATURDAY THROUGH THURSDAY/...
THE ARCTIC COLD FRONT IS ENTERING NWRN PA AS OF MID DAY....
A SFC LOW ASSOCIATED WITH THE COLD FRONT TRACK ESE ACROSS THE NRN
MID ATLANTIC STATES THIS AFTERNOON BEFORE RAPIDLY INTENSIFYING
JUST OFFSHORE SRN NEW ENGLAND TONIGHT INTO EARLY SUNDAY.
THE ARCTIC COLD FRONT WILL MOVE THROUGH THE FLYING AREA AND BE
THE FOCUS FOR LOCALLY HEAVY SNOW SQUALLS THIS AFTERNOON AND
EVENING...WITH AN AREA OF PRE-FRONTAL LIGHT SNOW AND MVFR/IFR
CONDITIONS ALREADY IMPACTING THE WRN 1/3 TO 1/2 OF THE AIRSPACE.
OVERALL EXPECT PREVAILING IFR ACROSS THE HIGHER ELEVATION SITES
FROM JST UP THROUGH BFD. CENTRAL TERMINALS WILL SEE PERIODS OF
IFR BUT MVFR WILL MORE LIKELY BE THE PREVAILING FLIGHT CAT.
PREVAILING VFR WITH PERIODS OF MVFR CAN BE EXPECTED AT THE SERN
SITES. USED 1HR TEMPO TO SHOW BEST TIME WINDOW FOR HEAVY SNOW AND
REDUCED CONDITIONS ASSOCIATED WITH EXPECTED SNOW SQUALL
ACTIVITY...WITH A SHARP DROP IN VIS TO 1/2 MILE OR LESS. WIND WILL
BECOME THE MAIN CONCERN LATER TONIGHT INTO EARLY SUNDAY WITH
PEAK GUSTS IN THE 35-45KT RANGE FROM AROUND 300 DEGREES. MVFR/IFR
IN OCNL SHSN WILL LINGER OVER THE WRN TERMINALS INTO SUNDAY WITH
GRADUAL IMPROVEMENT EXPECTED DURING THE DAY. ELSEWHERE LOOK FOR A
RETURN TO LOW VFR WITH CIGS BTWN 3000-5000`.
OUTLOOK...
MON-TUE...VFR/NO SIG WX.
WED-THU...MVFR/IFR SHSN WEST. VFR/MVFR EAST.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 7 AM EST SUNDAY FOR PAZ004>006-
010>012-017>019-024>028-033>037-041-042-045-046-049>053-
056>059-063>066.
WIND ADVISORY FROM 7 PM THIS EVENING TO NOON EST SUNDAY FOR
PAZ012-017>019-024>028-033>035-037-041-042-045-046-049>053.
WIND CHILL WARNING FROM MIDNIGHT TONIGHT TO 10 AM EST MONDAY
FOR PAZ012-018-019-025>028-034>037-041-042-045-046-049>053-
056>059-063>066.
WIND CHILL WARNING FROM 7 PM THIS EVENING TO 10 AM EST MONDAY
FOR PAZ004>006-010-011-017-024-033.
HIGH WIND WARNING FROM 7 PM THIS EVENING TO NOON EST SUNDAY
FOR PAZ036-056>059-063>066.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...LA CORTE
SHORT TERM...LA CORTE
LONG TERM...LAMBERT/RXR
AVIATION...LA CORTE
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
110 PM EST SAT FEB 14 2015
.SYNOPSIS...
AN ARCTIC COLD FRONT WILL SWEEP THROUGH THE COMMONWEALTH THIS
AFTERNOON AND EVENING. THE COLDEST AIR OF THE SEASON WILL BE WITH
US SUNDAY INTO EARLY MONDAY ALONG WITH DANGEROUSLY LOW WIND CHILLS
OF 20 TO 35 BELOW ZERO. THE NEXT CHANCE FOR SNOW WILL BE AROUND
MID WEEK AS AN AREA OF LOW PRESSURE MOVES NORTHEAST FROM THE GULF
COAST STATES.
&&
.NEAR TERM /THROUGH TONIGHT/...
MESO ANAL INDICATES THE ARCTIC COLD FRONT AT MID DAY IS ENTERING
FAR NWRN PA. RADAR SHOWS A DEVELOPING LINE OF SNOW SHOWERS AND
SQUALLS ALONG THE SHARP CONVERGENCE ZONE. LOCALLY WE HAVE A
WIDESPREAD AREA OF FAIRLY LIGHT SNOW BEING FORCED BY STRONG WARM
ADVECTION AHEAD OF THE APPROACHING FRONT. HIGHER ELEVATIONS TO OUR
WEST HAVE EXPERIENCED SMALL ACCUMS OF AN INCH OR 2...WHILE JUST
EAST OF THE HIGHER TERRAIN AMOUNTS HAVE BEEN OF THE NUISANCE OR
DUSTING VARIETY.
HIGH RES MODELS CONTINUE TO INDICATE A LINE OF SNOW SQUALLS NOW
ENTERING NW PORTIONS OF THE REGION...PROGRESSING OFF TO THE EAST
THEREAFTER. RAP DEVELOPS SOME IMPRESSIVE INSTABILITY FOR MID
FEBRUARY...WITH STEEPENING LOW-MID LEVEL LAPSE RATES AND EVEN
COOKING UP A COUPLE OF HUNDRED JOULES OF CAPE IN RESPONSE TO
RAPIDLY FALLING HEIGHTS AND TEMPS ALOFT.
CURRENT TIMING HAS THE COLD FRONT/SQUALL LINE MOVING THROUGH
BRADFORD AROUND 20Z/3PM...MOVING EAST TO A LINE FROM JOHNSTOWN
THROUGH CLEARFIELD UP INTO COUDERSPORT AROUND 21Z/4PM...AND INTO
RENOVO-STATE COLLEGE-ALTOONA BY 22Z/5PM. EAST OF THE CENTRAL
MOUNTAINS THE HRRR TRIES TO MAKE THE SQUALL LINE MORE
DISORGANIZED SO TIMING MAY BE MORE NEBULOUS.
I WOULD NOT RULE OUT A LITTLE THUNDER SNOW AS THE FORCING LOOKS
ESPECIALLY ROBUST FOR THE TIME OF YEAR.
TEMPS IN THE 20S TO LOWER 30S AHEAD OF THE FRONT AND THE
POTENTIAL FOR WET/PRE-TREATED ROADS FROM ANY LIGHT SNOW AHEAD OF
THE FRONT...WILL LEAD TO A DANGEROUS...FLASH FREEZE SETUP AS THE
ARCTIC FRONT PLOWS EAST ACROSS THE STATE ACCOMPANIED BY ONE OR TWO
DISTINCT NORTH/SOUTH BANDS OF BLINDING SNOW SQUALLS...SHARPLY
FALLING TEMPS...AND WIND GUSTS OF 35-45 MPH. HAZARDOUS INTERSTATE
TRAVEL CONDITIONS ARE EXPECTED TO DEVELOP FROM WEST TO EAST THIS
AFTERNOON.
A WINTER WX ADVISORY COVERS MUCH OF CENTRAL PA THROUGH 12Z SUNDAY
AS MODEL BLENDED QPF COMBINED WITH SLR/S OF CLOSE TO 20/1 SUPPORT
A GENERAL 2-4 INCH SNOWFALL TODAY AND TONIGHT FROM THE ONE-TWO
PUNCH OF THE ARCTIC FRONT...THEN PERIODS OF SNOW/SNOW SHOWERS
ASSOCIATED WITH THE PASSAGE OF THE SE DIGGING CLOSED UPPER LOW.
THE HIGHER SNOWFALL AMOUNTS WILL BE CONFINED TO MAINLY THE NW
MTNS...WRN POCONOS AND ENDLESS MTNS OF NEPA...AND THE LAUREL
HIGHLANDS IN THE SOUTHWEST.
EVEN THOSE LOCATIONS THAT FALL SHORT OF ADVISORY CRITERIA SNOW
WILL HAVE TO CONTEND WITH AREAS OF BLOWING/DRIFTING SNOW BEHIND
THE COLD FRONT LATE TODAY AND TONIGHT. BUFKIT SOUNDINGS SUPPORT
FREQUENT GUSTS IN THE 35-40KT RANGE IN WAKE OF FRONT ACROSS MUCH
OF THE CENTRAL RIDGE AND VALLEY REGION...LASTING THRU TONIGHT.
EVEN HIGHER GUSTS...OCNLY UP TO BETWEEN 45-50 KTS APPEAR LIKELY
ACROSS THE REGION NEAR AND TO THE SE OF I-81...SO THE HIGH WIND
WATCH TRANSITIONED TO A HIGH WIND WARNING THERE. THE HIGH WIND
WARNING AND WIND ADVISORY RUNS THROUGH NOON SUNDAY.
THE LOW SHOULD BE QUICKLY RE-DEVELOPING OVER EASTERN PA OR OVER
THE COASTAL WATERS BY EVENING...WITH THE LOCAL AREA TRANSITIONING
INTO A POST COLD FRONTAL FLOW PATTERN. WITH THE LOW EXPECTED TO
BE DEEPENING RAPIDLY...STRONG GUSTY WINDS WILL DEVELOP AND
CONTINUE INTO THE OVERNIGHT CAUSING WIND CHILLS TO DIP TO
DANGEROUSLY LOW LEVELS OVER THE ENTIRE FCST AREA. AFTER
COLLABORATION WITH SURROUNDING WFOS WE DECIDED TO ISSUE A WIND
CHILL WARNING FOR THE ENTIRE CWA TONIGHT THROUGH MONDAY MORNING.
ACTUAL AIR TEMPERATURES WILL PLUMMET TONIGHT TO BETWEEN 5 AND 15
DEGREES BELOW ZERO ACROSS THE NORTHWEST MOUNTAINS AND LAUREL
HIGHLANDS...AND SETTLE BETWEEN ZERO AND 5 ABOVE THROUGHOUT THE
LARGER METRO AREAS OF THE LOWER SUSQUEHANNA VALLEY.
&&
.SHORT TERM /SUNDAY/...
SHALLOW STRATO CU CLOUDS CLOUDS SHOULD BREAK ALONG AND TO THE SE
OF THE I-99/I-80/RT 220 CORRIDOR SUNDAY AS HIGH PRESSURE BUILDS
EAST FROM THE OHIO VALLEY LATE IN THE DAY. SCATTERED FLURRIES WILL
OCCUR SUNDAY AFTERNOON ACROSS THE CENTRAL ZONES...WHILE THE NW
MTNS AND LAURELS COULD SEE LOCALLY UP TO ANOTHER ADDITIONAL
COATING TO ONE INCH FROM SCATTERED SNOW SHOWERS.
HIGH TEMPERATURES WILL STRUGGLE TO REACH 5 BELOW ZERO ACROSS THE
NORTHWEST MOUNTAINS...AND WILL ONLY MAKE IT TO 10 TO 12 DEGREES
ABOVE ZERO ACROSS THE LOWER SUSQUEHANNA VALLEY.
&&
.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
VERY COLD AIR WILL CONTINUE TO IMPACT THE REGION THROUGH AT LEAST
THE NEXT WEEK AS STRONG RIDGE OVER WESTERN U.S. CONTINUES TO
DIRECT POLAR AIR INTO THE EASTERN U.S. VIA PERSISTENT TROUGH.
ALTHOUGH WINDS WILL GRADUALLY RELAX INTO MON...COMBINATION OF
COLD TEMPS AND WIND JUSTIFIES THE WIND CHILL WATCH CURRENTLY IN
EFFECT THROUGH THAT 36HR PERIOD. THIS WILL LIKELY NEED TO BE
UPGRADED TO A WARNING AS EVENT WINDOW APPROACHES. WILL ALSO NEED
TO STRONGLY CONSIDER A WIND ADVISORY ESP FOR HIGHER TERRAIN AND
NW-SE ALIGNED VALLEYS ACROSS SOUTHERN AREAS SAT NIGHT INTO EARLY
SUN WITH PEAK WIND GUSTS IN THE 40-50 MPH RANGE.
RECORD LOWS FOR THE DATE EARLY MONDAY APPEAR LIKELY. LOWS EARLY
MONDAY MORNING UNDER CLEAR TO PARTLY CLOUDY SKIES WITH DIMINISHING
WIND WILL EASILY AVERAGE 10-15 BELOW ZERO ACROSS THE NRN AND
WESTERN MTNS...AND 5-10 BELOW ZERO THROUGHOUT MUCH OF THE CENTRAL
RIDGE AND VALLEY REGION. SOME PROTECTED VALLEYS ACROSS THE NORTH
COULD DIP TO NEAR 25 BELOW BETWEEN 09-12Z MONDAY. SURFACE HIGH
WILL PROPAGATE ACROSS CENTRAL PA MONDAY AND MONDAY NIGHT...MOVING
OFFSHORE ON TUESDAY.
STILL AT LEAST SOME POTENTIAL INDICATED FOR SOME PHASING OF
NORTHERN AND SOUTHERN STREAM WAVES OVER THE GULF COAST AND
SOUTHEASTERN U.S. BY LATER TUE INTO WED...BRINGING THE CHANCE OF
SNOW TO THE REGION. HOWEVER...MODEL TRENDS OVER PREVIOUS FEW DAYS
CONTINUE TO LEND CREDENCE TOWARD A MORE SUPPRESSED/FLATTER
SOUTHERN STREAM SYSTEM WITH THE ARCTIC AIR DOMINATING THE GREAT
LAKES REGION AND NE U.S. AND THE BULK OF ANY STEADIER/STRATIFORM
PRECIP STAYING CONFINED TO THE SE U.S. AND MAYBE THE VIRGINIAS.
YET ANOTHER SURGE OF EXTREMELY COLD AIR RIDES IN ON PERSISTENT
NORTHWEST LATE NEXT WEEK...AS A MASSIVE RIDGE OF SURFACE HIGH
PRESSURE COVERS THE EASTERN HALF OF THE CONUS.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
THE ARCTIC COLD FRONT IS ENTERING NWRN PA AS OF MID DAY....
A SFC LOW ASSOCIATED WITH THE COLD FRONT TRACK ESE ACROSS THE NRN
MID ATLANTIC STATES THIS AFTERNOON BEFORE RAPIDLY INTENSIFYING
JUST OFFSHORE SRN NEW ENGLAND TONIGHT INTO EARLY SUNDAY.
THE ARCTIC COLD FRONT WILL MOVE THROUGH THE FLYING AREA AND BE
THE FOCUS FOR LOCALLY HEAVY SNOW SQUALLS THIS AFTERNOON AND
EVENING...WITH AN AREA OF PRE-FRONTAL LIGHT SNOW AND MVFR/IFR
CONDITIONS ALREADY IMPACTING THE WRN 1/3 TO 1/2 OF THE AIRSPACE.
OVERALL EXPECT PREVAILING IFR ACROSS THE HIGHER ELEVATION SITES
FROM JST UP THROUGH BFD. CENTRAL TERMINALS WILL SEE PERIODS OF
IFR BUT MVFR WILL MORE LIKELY BE THE PREVAILING FLIGHT CAT.
PREVAILING VFR WITH PERIODS OF MVFR CAN BE EXPECTED AT THE SERN
SITES. USED 1HR TEMPO TO SHOW BEST TIME WINDOW FOR HEAVY SNOW AND
REDUCED CONDITIONS ASSOCIATED WITH EXPECTED SNOW SQUALL
ACTIVITY...WITH A SHARP DROP IN VIS TO 1/2 MILE OR LESS. WIND WILL
BECOME THE MAIN CONCERN LATER TONIGHT INTO EARLY SUNDAY WITH
PEAK GUSTS IN THE 35-45KT RANGE FROM AROUND 300 DEGREES. MVFR/IFR
IN OCNL SHSN WILL LINGER OVER THE WRN TERMINALS INTO SUNDAY WITH
GRADUAL IMPROVEMENT EXPECTED DURING THE DAY. ELSEWHERE LOOK FOR A
RETURN TO LOW VFR WITH CIGS BTWN 3000-5000`.
OUTLOOK...
MON-TUE...VFR/NO SIG WX.
WED-THU...MVFR/IFR SHSN WEST. VFR/MVFR EAST.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 7 AM EST SUNDAY FOR PAZ004>006-
010>012-017>019-024>028-033-037-041-042-045-046-049>053-058.
WIND ADVISORY FROM 7 PM THIS EVENING TO NOON EST SUNDAY FOR
PAZ012-017>019-024>028-033>035-037-041-042-045-046-049>053.
WIND CHILL WARNING FROM MIDNIGHT TONIGHT TO 10 AM EST MONDAY
FOR PAZ012-018-019-025>028-034>037-041-042-045-046-049>053-
056>059-063>066.
WIND CHILL WARNING FROM 7 PM THIS EVENING TO 10 AM EST MONDAY
FOR PAZ004>006-010-011-017-024-033.
HIGH WIND WARNING FROM 7 PM THIS EVENING TO NOON EST SUNDAY
FOR PAZ036-056>059-063>066.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...LA CORTE
SHORT TERM...LA CORTE
LONG TERM...LAMBERT/RXR
AVIATION...LA CORTE
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1007 AM EST SAT FEB 14 2015
.SYNOPSIS...
AN ARCTIC COLD FRONT WILL SWEEP THROUGH THE COMMONWEALTH THIS
AFTERNOON AND EVENING. THE COLDEST AIR OF THE SEASON WILL BE WITH
US SUNDAY INTO EARLY MONDAY ALONG WITH DANGEROUSLY LOW WIND CHILLS
OF 20 TO 35 BELOW ZERO AS LOW PRESSURE DEEPENS RAPIDLY JUST EAST
OF THE NEW ENGLAND COAST. THE NEXT CHANCE FOR ACCUMULATING SNOW
WILL ARRIVE TUESDAY AFTERNOON INTO WEDNESDAY AS AN AREA OF LOW
PRESSURE MOVES NORTHEAST FROM THE GULF COAST STATES.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
MESO ANAL INDICATES THE ARCTIC COLD FRONT IS DROPPING INTO NRN
OHIO AS OF MID MORNING. LOCALLY WE HAVE A WIDESPREAD AREA OF
FAIRLY LIGHT SNOW BEING FORCED BY STRONG WARM ADVECTION AHEAD OF
THE APPROACHING FRONT.
THE LACK OF DEEP MOISTURE WILL LIMIT THE LIGHT SNOW ACCUMS TO
MAINLY THE NORTHERN MOUNTAINS...WHERE OROGRAPHIC LIFT WILL PLAY A
ROLE.
HIGH RES MODELS INDICATE A LINE OF SNOW SQUALLS ENTERING THE NW
PORTIONS OF THE REGION AROUND MID DAY...PROGRESSING OFF TO THE
EAST THEREAFTER. RAP DEVELOPS SOME IMPRESSIVE INSTABILITY FOR MID
FEBRUARY...WITH STEEPENING LOW-MID LEVEL LAPSE RATES AND EVEN
COOKING UP A COUPLE OF HUNDRED JOULES OF CAPE IN RESPONSE TO
RAPIDLY FALLING HEIGHTS AND TEMPS ALOFT.
CURRENT TIMING HAS THE COLD FRONT APPROACHING THE RT 219 CORRIDOR
IN WESTERN PA AROUND 19-20Z...RT 220/INTERSTATE 99 AROUND
21Z...AND THE MIDDLE AND LOWER SUSQ VALLEY 22-23Z TODAY.
WOULD NOT RULE OUT THUNDER SNOW AS THE DYNAMICS LOOK ESPECIALLY
ROBUST FOR THE TIME OF YEAR.
TEMPS IN THE 20S TO LOWER 30S AHEAD OF THE FRONT AND THE
POTENTIAL FOR WET/PRE-TREATED ROADS FROM ANY LIGHT SNOW AHEAD OF
THE FRONT...WILL LEAD TO A DANGEROUS...FLASH FREEZE SETUP AS THE
ARCTIC FRONT PLOWS EAST ACROSS THE STATE ACCOMPANIED BY ONE OR TWO
DISTINCT NORTH/SOUTH BANDS OF BLINDING SNOW SQUALLS...SHARPLY
FALLING TEMPS...AND WIND GUSTS OF 35-45 MPH. HAZARDOUS INTERSTATE
TRAVEL CONDITIONS ARE EXPECTED TO DEVELOP FROM WEST TO EAST THIS
AFTERNOON.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/...
A WINT WX ADVISORY COVERS MUCH OF CENTRAL PA FROM THE MID MORNING
HOURS TODAY...THROUGH 12Z SUNDAY AS MDL BLENDED QPF COMBINED WITH
SLR/S OF CLOSE TO 20/1 SUPPORT A GENERAL 2-4 INCH SNOWFALL TODAY
AND TONIGHT FROM THE ONE-TWO PUNCH OF THE ARCTIC FRONT...THEN
PERIODS OF SNOW/SNOW SHOWERS ASSOCIATED WITH THE PASSAGE OF THE SE
DIGGING CLOSED UPPER LOW. THE HIGHER SNOWFALL AMOUNTS WILL BE
CONFINED TO MAINLY THE NW MTNS...WRN POCONOS AND ENDLESS MTNS OF
NEPA...AND THE LAUREL HIGHLANDS IN THE SOUTHWEST.
EVEN THOSE LOCATIONS THAT FALL SHORT OF ADVISORY CRITERIA SNOW
WILL HAVE TO CONTEND WITH AREAS OF BLOWING/DRIFTING SNOW BEHIND
THE COLD FRONT LATE TODAY AND TONIGHT. BUFKIT SOUNDINGS SUPPORT
FREQUENT GUSTS IN THE 35-40KT RANGE IN WAKE OF FRONT ACROSS MUCH
OF THE CENTRAL RIDGE AND VALLEY REGION...LASTING THRU TONIGHT.
EVEN HIGHER GUSTS...OCNLY UP TO BETWEEN 45-50 KTS APPEAR LIKELY
ACROSS THE REGION NEAR AND TO THE SE OF I-81...SO THE HIGH WIND
WATCH TRANSITIONED TO A HIGH WIND WARNING THERE. THE HIGH WIND
WARNING AND WIND ADVISORY RUNS THROUGH NOON SUNDAY.
AFTER EXTENSIVE COLLABORATION WITH SURROUNDING WFOS /WITH KLWX
HAVING SLIGHTLY LOWER CRITERIA FOR THRESHOLD VALUES FOR BOTH WIND
CHILLS AND SNOWFALL TO OUR SOUTH/...WE DECIDED TO NOT SPLIT HAIRS
WITH THE EXTREME COLD AND ISSUE A WIND CHILL WARNING FOR THE
ENTIRE CWA TONIGHT THROUGH MONDAY MORNING.
ACTUAL AIR TEMPERATURES WILL PLUMMET TONIGHT TO BETWEEN 5 AND 15
DEGREES BELOW ZERO ACROSS THE NORTHWEST MOUNTAINS AND LAUREL
HIGHLANDS...AND SETTLE BETWEEN ZERO AND 5 ABOVE THROUGHOUT THE
LARGER METRO AREAS OF THE LOWER SUSQUEHANNA VALLEY. HIGH
TEMPERATURES SUNDAY WILL STRUGGLE TO REACH 5 BELOW ZERO ACROSS THE
NORTHWEST MOUNTAINS...AND WILL ONLY MAKE IT TO 10 TO 12 DEGREES
ABOVE ZERO ACROSS THE LOWER SUSQUEHANNA VALLEY.
SHALLOW STRATO CU CLOUDS CLOUDS SHOULD BREAK ALONG AND TO THE SE
OF THE I-99/I-80/RT 220 CORRIDOR SUNDAY AS HIGH PRESSURE BUILDS
EAST FROM THE OHIO VALLEY LATE IN THE DAY. SCATTERED FLURRIES WILL
OCCUR SUNDAY AFTERNOON ACROSS THE CENTRAL ZONES...WHILE THE NW
MTNS AND LAURELS COULD SEE LOCALLY UP TO ANOTHER ADDITIONAL
COATING TO ONE INCH FROM SCATTERED SNOW SHOWERS.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
VERY COLD AIR WILL CONTINUE TO IMPACT THE REGION THROUGH AT LEAST
THE NEXT WEEK AS STRONG RIDGE OVER WESTERN U.S. CONTINUES TO
DIRECT POLAR AIR INTO THE EASTERN U.S. VIA PERSISTENT TROUGH.
ALTHOUGH WINDS WILL GRADUALLY RELAX INTO MON...COMBINATION OF
COLD TEMPS AND WIND JUSTIFIES THE WIND CHILL WATCH CURRENTLY IN
EFFECT THROUGH THAT 36HR PERIOD. THIS WILL LIKELY NEED TO BE
UPGRADED TO A WARNING AS EVENT WINDOW APPROACHES. WILL ALSO NEED
TO STRONGLY CONSIDER A WIND ADVISORY ESP FOR HIGHER TERRAIN AND
NW-SE ALIGNED VALLEYS ACROSS SOUTHERN AREAS SAT NIGHT INTO EARLY
SUN WITH PEAK WIND GUSTS IN THE 40-50 MPH RANGE.
RECORD LOWS FOR THE DATE EARLY MONDAY APPEAR LIKELY. LOWS EARLY
MONDAY MORNING UNDER CLEAR TO PARTLY CLOUDY SKIES WITH DIMINISHING
WIND WILL EASILY AVERAGE 10-15 BELOW ZERO ACROSS THE NRN AND
WESTERN MTNS...AND 5-10 BELOW ZERO THROUGHOUT MUCH OF THE CENTRAL
RIDGE AND VALLEY REGION. SOME PROTECTED VALLEYS ACROSS THE NORTH
COULD DIP TO NEAR 25 BELOW BETWEEN 09-12Z MONDAY. SURFACE HIGH
WILL PROPAGATE ACROSS CENTRAL PA MONDAY AND MONDAY NIGHT...MOVING
OFFSHORE ON TUESDAY.
STILL AT LEAST SOME POTENTIAL INDICATED FOR SOME PHASING OF
NORTHERN AND SOUTHERN STREAM WAVES OVER THE GULF COAST AND
SOUTHEASTERN U.S. BY LATER TUE INTO WED...BRINGING THE CHANCE OF
SNOW TO THE REGION. HOWEVER...MODEL TRENDS OVER PREVIOUS FEW DAYS
CONTINUE TO LEND CREDENCE TOWARD A MORE SUPPRESSED/FLATTER
SOUTHERN STREAM SYSTEM WITH THE ARCTIC AIR DOMINATING THE GREAT
LAKES REGION AND NE U.S. AND THE BULK OF ANY STEADIER/STRATIFORM
PRECIP STAYING CONFINED TO THE SE U.S. AND MAYBE THE VIRGINIAS.
YET ANOTHER SURGE OF EXTREMELY COLD AIR RIDES IN ON PERSISTENT
NORTHWEST LATE NEXT WEEK...AS A MASSIVE RIDGE OF SURFACE HIGH
PRESSURE COVERS THE EASTERN HALF OF THE CONUS.
&&
.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
A SFC LOW LOCATED OVER SRN ONTARIO AT 12Z WILL TRACK ESE ACROSS
THE NRN MID ATLANTIC STATES THIS AFTERNOON BEFORE RAPIDLY
INTENSIFYING JUST OFFSHORE SRN NEW ENGLAND TONIGHT INTO EARLY
SUNDAY.
AN ARCTIC COLD FRONT WILL MOVE THROUGH THE FLYING AREA AND BE THE
FOCUS FOR LOCALLY HEAVY SNOW SQUALLS THIS AFTERNOON AND
EVENING...WITH AN AREA OF PRE-FRONTAL LIGHT SNOW AND MVFR/IFR
CONDITIONS ALREADY IMPACTING THE WRN 1/3 TO 1/2 OF THE AIRSPACE.
OVERALL EXPECT PREVAILING IFR ACROSS THE HIGHER ELEVATION SITES
FROM JST UP THROUGH BFD. CENTRAL TERMINALS WILL SEE PERIODS OF
IFR BUT MVFR WILL MORE LIKELY BE THE PREVAILING FLIGHT CAT.
PREVAILING VFR WITH PERIODS OF MVFR CAN BE EXPECTED AT THE SERN
SITES. USED 1HR TEMPO TO SHOW BEST TIME WINDOW FOR HEAVY SNOW AND
REDUCED CONDITIONS ASSOCIATED WITH EXPECTED SNOW SQUALL
ACTIVITY...WITH A SHARP DROP IN VIS TO 1/2 MILE OR LESS. WINDS
BECOME THE MAIN CONCERN LATER TONIGHT INTO EARLY SUNDAY WITH PEAK
GUSTS IN THE 35-45KT RANGE FROM AROUND 300 DEGREES. MVFR/IFR IN
OCNL SHSN WILL LINGER OVER THE WRN TERMINALS INTO SUNDAY WITH
GRADUAL IMPROVEMENT EXPECTED DURING THE DAY. ELSEWHERE LOOK FOR A
RETURN TO LOW VFR WITH CIGS BTWN 3000-5000`.
OUTLOOK...
MON...VFR/NO SIG WX.
TUE...CHC OF IFR/SNOW SOUTHERN/EASTERN AIRSPACE.
WED...MVFR/IFR SHSN WEST. VFR/MVFR EAST.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 7 AM EST SUNDAY FOR PAZ012-018-
019-025>028-037-041-042-045-046-049>053-058.
WIND ADVISORY FROM 7 PM THIS EVENING TO NOON EST SUNDAY FOR
PAZ012-017>019-024>028-033>035-037-041-042-045-046-049>053.
WIND CHILL WARNING FROM MIDNIGHT TONIGHT TO 10 AM EST MONDAY
FOR PAZ012-018-019-025>028-034>037-041-042-045-046-049>053-
056>059-063>066.
WINTER WEATHER ADVISORY UNTIL 7 AM EST SUNDAY FOR PAZ004>006-
010-011-017-024-033.
WIND CHILL WARNING FROM 7 PM THIS EVENING TO 10 AM EST MONDAY
FOR PAZ004>006-010-011-017-024-033.
HIGH WIND WARNING FROM 7 PM THIS EVENING TO NOON EST SUNDAY
FOR PAZ036-056>059-063>066.
&&
$$
SYNOPSIS...LA CORTE/LAMBERT
NEAR TERM...LA CORTE/LAMBERT
SHORT TERM...LAMBERT
LONG TERM...LAMBERT/RXR
AVIATION...STEINBUGL/LA CORTE
AREA FORECAST DISCUSSION
NWS ABERDEEN SD
319 PM CST SAT FEB 14 2015
.SHORT TERM...TONIGHT THROUGH MONDAY NIGHT
WATCHING AN AREA OF RADAR RETURNS ACROSS THE CENTRAL
DAKOTAS...WITH OBS SHOWING SNOW ACROSS ND BUT YET TO SEE ANYTHING
OF SIGNIFICANCE ACROSS SD. WEB CAM AT LEMMON DOES APPEAR TO SHOW
LIGHT SNOW HAS BEGUN. STILL A DECENT AMOUNT OF DRY AIR TO OVERCOME
BASED ON RAP SOUNDINGS BUT IMAGINE MBG WILL BEGIN REPORTING -SN
BEFORE TOO LONG. HAVE SCALED BACK SNOW AMOUNTS JUST A BIT ACROSS
THE EASTERN CWA GIVEN THE MOISTENING OF THE ATMOSPHERE THAT WILL
HAVE TO TAKE PLACE FIRST. SHOULD STILL BE ABLE TO SEE AROUND IN
INCH FOR MOST PLACES ALONG AND EAST OF THE JAMES VALLEY. SYSTEM
LOOKS TO BE OUT OF HERE BY SUNDAY AFTERNOON WITH WARMER
TEMPERATURES MOVING BACK IN. ANOTHER COLD FRONT IN ON TRACK TO
SWEEP SOUTH ACROSS THE AREA MONDAY AFTERNOON...BRINGING ANOTHER
SHOT OF GUSTY NORTH WINDS AND COLD AIR TO THE REGION.
.LONG TERM...TUESDAY THROUGH SATURDAY
VERY GOOD AGREEMENT WITH THE MODELS IN THE LONG TERM WITH THE UPPER
LEVEL LONG WAVE PATTERN ALONG WITH THE SURFACE FEATURES. THE LONG
TERM LOOKS TO HAVE MAINLY BELOW TO MUCH BELOW NORMAL TEMPERATURES
THROUGH AT THE LEAST TUESDAY...WEDNESDAY AND THURSDAY. A LARGE UPPER
LEVEL LOW PRESSURE TROUGH ACROSS EASTERN CANADA AND THE EASTERN US
THROUGH MOST OF THE PERIOD WILL BRING PREVAILING FLOW FROM CANADA
AND THE ARCTIC. AT THE SURFACE...A COUPLE HIGH PRESSURE AREAS WILL
MOVE ACROSS THE REGION FROM THE NORTH. THERE WILL ALSO BE A FEW
WEAK UPPER LEVEL SHORT WAVE TROUGHS AND SURFACE COLD FRONTS MOVING
THROUGH BRINGING SOME CHANCES OF LIGHT SNOW/FLURRIES WITH THEM.
LEFT IT MAINLY DRY THROUGH THE LONG TERM AT THIS TIME. TEMPERATURES
MAY RISE CLOSER TO NORMAL TO SLIGHTLY ABOVE NORMAL OUT WEST BY
FRIDAY AND SATURDAY.
&&
.AVIATION...
18Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
AN UPPER LEVEL LOW PRESSURE TROUGH ALONG WITH WAA WILL SPREAD LIGHT
SNOW AND LOWERING CEILINGS ACROSS THE REGION THROUGH THE AFTERNOON
AND EARLY TONIGHT. EXPECT IFR/MVFR CEILINGS AND VISIBILITIES AT
MBG...ABR AND ATY FOR A TIME AS THIS SYSTEM MOVES THROUGH. PIR MAY
HAVE A BRIEF PERIOD OF LIGHT SNOW THIS AFTERNOON BUT OVERALL
EXPECT THEM TO BE DRY. ALSO...EXPECT A PERIOD OF MVFR CEILINGS AT
PIR AS LOW CLOUDS RETURN BACK TO THE NORTH AND EAST.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
SHORT TERM...TMT
LONG TERM...MOHR
AVIATION...MOHR
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION...UPDATED
NWS SAN ANGELO TX
938 PM CST Sun Feb 15 2015
.UPDATE...
The strong cold front has advanced south and at 915 PM extended
from the northern border of Sterling County to the northern border
of Brown county. The latest RUC13 takes this front south to a
Brownwood to Grape Creek line by Midnight, and has the front
reaching the I-10 corridor by 5-6 AM Monday. Temperatures behind
the front have already dropped into the mid 30s in our northern
counties. The showers have moved east of our counties, while
freezing drizzle has developed farther north in southwestern
Oklahoma, where temperatures have dropped below freezing. We could
have some light rain or drizzle, changing to light freezing rain
or drizzle overnight across the Big Country and roughly the
northern third of our area, where temperatures drop to or below
freezing. However, confidence is low that this will be persistent
or widespread enough to cause travel problems. Having mentioned
this, cannot rule out possibility of a little ice on elevated
surfaces and a few slick spots may develop on a few bridges and
overpasses. The latest NAM and RUC moisten the boundary layer
tonight, but are short of saturation across the area of concern
in our northern counties.
With the above considerations, not planning to issue a Winter Weather
Advisory for our northern counties at this time. However, we will
monitor the situation closely and may need to add an advisory if
conditions or expectations change. For now, will update the
forecast to reflect a little faster timing with the front, and to
adjust temperatures and winds accordingly.
19
&&
.PREV DISCUSSION... /ISSUED 722 PM CST Sun Feb 15 2015/
UPDATE...
Strong cold front has advanced south into our northern counties
and was just north of Sweetwater and Abilene at 715 PM. This
front is making a little faster progress than previously
expected, and the RUC model appears to have the best handle
on the southward progression of this front tonight. Temperatures
behind the front have already dropped into the upper 30s to lower
40s. Rain showers are occurring across the area north of I-20 and
east of an Aspermont to Abilene line. This is where we have the
highest PoPs tonight. Will have a possibility of light rain or
freezing rain across our northern counties by late tonight, as
surface temperatures drop to or just below the freezing mark.
Forecast has been updated for tonight mainly for winds based on
the RUC, and have adjusted temperatures, winds and dewpoints to
bring in line with current/recent trends in the northern part of
our area.
19
PREV DISCUSSION... /ISSUED 555 PM CST Sun Feb 15 2015/
AVIATION...
/00Z TAFS/
A strong cold front continues to move south into the area this
evening. The front is expected to make it to KABI by 02Z/8PM or
03Z/9PM this evening. Behind it, CIGS are expected to quickly
deteriorate into the MVFR category to around 1500 feet. In
addition, at the KABI terminal, -SHRA or -DZ is expected to
develop after 05Z/11PM tonight, continuing intermittently through
most of the overnight hours. Expect the precipitation to end by
early tomorrow morning, leaving MVFR CIGS behind through most of
the morning before they start to lift for the afternoon hours
tomorrow. Similar conditions expected farther south, minus the
precipitation. The front should be through KSJT and KBBD by
09Z/3AM or 10Z/4AM tonight, possibly a little earlier, and will
check the timing of the front with the next TAF forecast issuance
if the front speeds up. KSOA and KJCT can expect the front an hour
or two later. While there may be some isolated precipitation at
the southern 4 sites, do not think there will be enough to mention
in the TAFs at this time. CIGS should lift at the other sites by
18Z/12PM tomorrow as well. 20
PREV DISCUSSION... /ISSUED 251 PM CST Sun Feb 15 2015/
SHORT TERM...
(Tonight and Tomorrow)
An upper low over the central Baja Peninsula early this afternoon
will weaken as it moves to the east and is sheared into the
southwestern flow aloft of a broad upper trough positioned over
the central CONUS. A cold front associated with the large upper
trough was moving south through the northern Panhandle early this
afternoon and will enter the Big Country late this evening. By
midnight the front should be along the Interstate 20 corridor.
Temperatures for tonight will be slow to drop with temperatures
just reaching the freezing mark over the Big Country around
sunrise. Temperatures will warm quickly after sunrise over the Big
Country with only a few hours of freezing temperatures expected.
Consequently, any light rain and freezing rain mix over the Big
Country will be short-lived and will at most affect only elevated
surfaces for a few hours.
For the remainder of the forecast area south of the Big Country,
morning lows will range from the mid 30s over the central CWA and
the 40s along the Interstate 10 corridor, with any precipitation
falling being in the liquid state. The cold front will push
completely through the forecast area before noon. Rain chances
will end from north to south during the day tomorrow with
afternoon highs reaching the mid 40s over the Big Country and the
upper 40s to around 50 over the southern CWA.
15
LONG TERM...
(Monday night through Sunday)
The shortwave trough currently located over British Columbia will
dive south over the next 24-36 hours, bringing another chance
for light precipitation to the area Monday night into Tuesday
morning. Lift associated with this system does not appear all that
favorable for a significant precipitation event. However, with
additional mesoscale forcing, there should be enough ascent to
generate light precipitation across the area, mainly beginning
after midnight. Point soundings indicate cooling aloft, eroding
the warm nose by the onset of precipitation. The question is how
much dry air will need to be moistened in the lowest few
kilometers. The GFS soundings indicate that significant moistening
will need to take place, while the NAM keeps the boundary layer
nearly saturated. The latter seems to represent an observed bias
with the NAM.
Either way, after midnight, light snow (possibly mixed with some
light sleet) will be possible across much of the CWA, with light
rain confined to the northwest Hill Country. This trend is
expected to continue into Tuesday morning, with precipitation
coming to an end by midday. Accumulations are expected to be minor
(at best) with this system. A dusting of snow is possible, mainly
north of a Sterling City to Cross Plains line, with little to no
accumulations elsewhere. Temperatures are forecast to drop into
the upper 20s, but limited QPF will zap any potential for heavier
snow.
Skies will clear as we move into Tuesday afternoon/evening. Expect
afternoon temperatures to warm into the upper 40s with winds
becoming light from the west/southwest. These light winds, dry
air, and clear skies will allow temperatures to fall into the
upper 20s and lower 30s by Wednesday morning. These cold
temperatures will be a distant memory by the afternoon, as
temperatures rebound back into the lower 60s across most of West
Central TX. The warming trend will continue on Thursday, with
highs in the mid/upper 60s.
We continue to monitor a pattern change heading into the weekend.
The West Coast ridges persists, but the ridge axis shifts back
to the west as a potent trough digs south along the Great Divide.
The flow aloft becomes briefly quasi-zonal by Friday, backing to
the southwest over the weekend as the aforementioned trough digs
toward the Four Corners. This is setting the stage for another
dump of cold air across the Plains. Just how cold remains in
question, but there is good agreement in the medium range models
that a cold front will move across the area by Sunday.
Ahead of this front, the models are developing light QPF across
central TX in response to warm advection and an open gulf. Broad
isentropic ascent is expected across the region Friday and
Saturday. Low PoPs were maintained for Saturday, but may need to
added for some areas on Friday if the latest trends hold. The 12z
ECMWF is much more aggressive with the weekend cold front compared
to the GFS/DGEX, but all of these models develop some QPF across
the area at some point with this system. We`ll continue to monitor
this system as the models zero in on a favored solution.
Johnson
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 32 46 27 49 33 / 50 20 30 20 5
San Angelo 36 50 28 50 30 / 30 20 20 20 0
Junction 48 50 31 51 30 / 20 20 20 20 5
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION...CORRECTED
NWS FORT WORTH TX
820 PM CST SUN FEB 15 2015
.AVIATION...
THE 02Z /8PM/ SURFACE ANALYSIS INDCITED THAT EH FRONT IS MOVING A
LITTLE FASTER TO THE SOUTHEAST THAN WE HAD EARLIER FORECAST. GUSTY
NORTHERLY WINDS HAVE MOVED INTO KRPH /GRAHAM/ AND KBKD /BRECKENRIDGE/
AS OF 02Z. EXPECT THE FRONT TO MOVE INTO THE METROPLEX AROUND 07Z
AS INDICATED BY THE 00Z RUNS OF THE RAP AND NAM AND THE 23Z RUN OF
THE HRRR.
58
.../PREVIOUS AVIATION DISCUSSION/...
/ISSUED AT 640 PM CST SUN FEB 15 2015/
CONCERNS...TIMING OF A COLD FRONT OVERNIGHT TONIGHT THAT WILL
BRING GUSTY NORTHERLY WINDS AND LOWERED CEILINGS. TEMPERATURES MAY
APPROACH FREEZING MONDAY MORNING AT KAFW...MID 30S AT THE REST OF
THE METROPLEX AIRPORTS.
AT 00Z MONDAY...A SURFACE LOW WAS CENTERED OVER SOUTHEASTERN NEW
MEXICO BETWEEN KCVS /CLOVIS/ AND KHOB /HOBBS/. A FRONT EXTENDED
FROM THE SURFACE LOW TO SOUTH OF KSPS /WICHITA FALLS/...KTKI
/MCKINNNEY/ AND KF44 /ATHENS/. AS THE SURFACE LOW MOVES SOUTHEAST
AND THEN EAST...THE COLD FRONT WILL SINK SOUTH ACROSS THROUGH THE
REGION OVERNIGHT TONIGHT INTO MONDAY MORNING.
SOUTH TO SOUTHEAST SURFACE WINDS OF 12 TO 15 KNOTS AT 00Z WILL
SHIFT TO THE NORTH AT 20 KNOTS IN THE METROPLEX AROUND 09Z AS THE
FRONT MOVES THROUGH THE AREA. GUSTS TO 30 KNOTS ARE EXPECTED FOR
MOST OF THE DAY MONDAY. LOWER END VFR CEILINGS /3500-4000 FEET/
WILL FALL TO MVFR BY 04Z...AND MAY FALL INTO THE IFR CATEGORY 11-13Z.
CEILINGS ARE EXPECTED TO IMPROVE TO VFR BY 22Z MONDAY. SOME LIGHT
RAIN IS POSSIBLE THROUGH MONDAY MORNING. TEMPERATURES WILL FALL
TO BETWEEN 34 TO 37 DEGREES BETWEEN 13 AND 17Z MONDAY...AT MOST OF
THE METROPLEX TAF SITES. AT KAFW...TEMPERATURES MAY FALL TO
FREEZING MONDAY MORNING.
WACO...SOUTH WINDS AND MOSTLY MVFR CEILINGS ARE EXPECTED OVERNIGHT.
THE COLD FRONT SHOULD MOVE THROUGH AROUND 11Z WITH A WIND SHIFT TO
THE NORTH AROUND 15 KNOTS WITH GUSTS OVER 25 KNOTS. SCATTERED SHOWERS
ARE POSSIBLE THROUGH MONDAY MORNING.
58
&&
.PREV DISCUSSION... /ISSUED 344 PM CST SUN FEB 15 2015/
EARLY AFTERNOON WATER VAPOR SATELLITE IMAGERY SHOWED A SHORTWAVE
TROUGH OVER THE UTAH/WYOMING/COLORADO BORDERS...MOVING SOUTHEAST.
WATER VAPOR IMAGERY ALSO SHOWED A COMPACT CUT OFF LOW WHICH WAS
NEARLY STATIONARY OVER BAJA CALIFORNIA. 12Z SUBJECTIVE UPPER AIR
ANALYSIS SHOWED A LARGE AND INTENSE UPPER TROUGH OVER THE
NORTHEASTERN CONUS WITH UPPER LEVEL RIDGING OVER THE WESTERN COAST
OF NORTH AMERICA. THE STRONG UPPER TROUGH OVER THE NORTHEASTERN
CONUS HAD USHERED IN SOME VERY COLD AIR INTO THE CONUS EXTENDING
FROM THE NORTHERN PLAINS...SOUTHEAST TO SOUTH CAROLINA AT THE 850
MB LEVEL. SURFACE ANALYSIS INDICATED THAT A SHALLOW WEDGE OF THIS
COLD AIR HAD MADE IT AS FAR SOUTHWEST AS OKLAHOMA INTO NORTHERN
MISSISSIPPI. 19Z SUBJECTIVE REGIONAL SURFACE ANALYSIS SHOWED A
DEEPENING CYCLONE CENTERED OVER SOUTHEASTERN NEW MEXICO. A STRONG
BAROCLINIC ZONE EXTENDING EAST FROM THIS LOW WAS ANALYZED ACROSS
THE SOUTHERN TEXAS PANHANDLE...THEN ALONG THE RED RIVER TO SHERMAN
BEFORE DIPPING SOUTHEAST ACROSS EAST TEXAS AND CENTRAL LOUISIANA.
THE TEMPERATURE GRADIENT ON EITHER SIDE OF THIS BAROCLINIC ZONE
WAS FAIRLY IMPRESSIVE WITH A 38 DEGREE TEMPERATURE OBSERVED AT
AMARILLO AND A 75 DEGREE TEMPERATURE OBSERVED AT LUBBOCK.
ACROSS NORTH TEXAS...TEMPERATURES WERE GENERALLY OBSERVED IN THE
UPPER 60S TO LOWER 70S...EXCEPT FOR LOCATIONS ALONG AND NORTH OF A
SHERMAN TO EMORY LINE...WHERE TEMPERATURES WERE IN THE LOWER TO
MID 50S. THIS LINE REPRESENTS THE BAROCLINIC ZONE DESCRIBED
ABOVE...WHICH WAS BEHAVING LIKE A WARM FRONT EARLY THIS AFTERNOON
AND WAS SLOWLY ADVANCING NORTH TOWARDS THE RED RIVER. TO THE
SOUTHWEST OF THIS BOUNDARY...REGIONAL RADARS SHOWED SCATTERED RAIN
SHOWERS OVER MOST OF NORTH AND CENTRAL TEXAS. WHILE THE RADAR
LOOKS VERY BUSY...NOT MANY SITES WERE ACTUALLY REPORTING
PRECIPITATION AS OF 300 PM CST. THE 12Z FWD RAOB WAS FAIRLY
DRY...SO THESE MID-LEVEL BASED RAIN SHOWERS ARE ESSENTIALLY
WORKING TO SATURATE THE ATMOSPHERE FROM THE TOP DOWN THIS
AFTERNOON. EXPECT THAT MORE AND MORE RAIN WILL REACH THE SURFACE
AS THIS PROCESS CONTINUES THROUGH SUNSET. HAVE THE HIGHEST POPS
WEST OF INTERSTATE 35 THROUGH SUNSET ASSUMING IT WILL BE DIFFICULT
TO GET MEASURABLE RAINFALL FARTHER EAST BEFORE 00Z...SIMPLY
BECAUSE IT HAS NOT BEEN RAINING EAST OF INTERSTATE 35 AS LONG AS
IT HAS BEEN TO THE WEST.
THIS EVENING...THE UT/WY/CO SHORTWAVE TROUGH IS EXPECTED TO
CONTINUE TO DIG SOUTHEAST BEFORE MOVING EAST OVER OKLAHOMA
TOMORROW MORNING. THE SHORTWAVE TROUGH IS EXPECTED TO REMAIN NORTH
OF THE CWA PRIMARILY BECAUSE OF THE INFLUENCE OF A STRONGER
SHORTWAVE TROUGH THAT IS EXPECTED TO DIG SOUTH OVER THE CONUS
ROCKIES THROUGHOUT THE DAY ON MONDAY. THIS SECOND TROUGH IS
EXPECTED TO KICK THE LEAD TROUGH OFF TO THE EAST-NORTHEAST...AND
SHOULD ALSO CAUSE THE BAJA UPPER LOW TO MOVE NORTHEAST WHILE
WEAKENING/BECOMING SHEARED APART.
WHAT ALL OF THIS UPPER LEVEL ACTIVITY SHOULD MEAN FOR US IS THAT
THE BEST LARGE SCALE FORCING FOR ASCENT SHOULD REMAIN OVER THE
NORTHERN PORTIONS OF THE CWA...RESULTING IN HIGHER RAINFALL
AMOUNTS HOLDING NORTH OF INTERSTATE 20 OVER THE NEXT 24 HOURS. THIS
UPPER LEVEL ACTIVITY WILL ALSO SEND THE SURFACE LOW EAST...AND THE
ACCOMPANYING BAROCLINIC ZONE SHOULD SURGE SOUTH AS A STRONG COLD
FRONT IN THE WAKE OF THE SURFACE LOW. AS MENTIONED ABOVE...THE
BAROCLINICITY ASSOCIATED WITH THIS FRONT IS ALREADY QUITE
HIGH...SO EXPECT STRONG FRONTOGENETIC FORCING ALONG AND BEHIND THE
COLD FRONT AS IT SURGES SOUTH ACROSS THE CWA THIS EVENING AND
OVERNIGHT. ASSUMING THE ATMOSPHERE DOES BECOME SATURATED FROM THE
MID-LEVELS DOWN TO THE SURFACE DUE TO ONGOING ELEVATED RAIN
SHOWERS...EXPECT THAT MOST LOCATIONS WILL RECEIVE MEASURABLE
RAINFALL AS THE FRONT MOVES ACROSS THE REGION. THE STRENGTH OF THE
BAROCLINICITY ALONG THE BOUNDARY RIGHT NOW...COMBINED WITH THE
WIDESPREAD RADAR RETURNS OVER MOST OF THE CWA AT THE TIME OF THIS
DISCUSSION INCREASES CONFIDENCE IN RAIN CHANCES ACROSS THE CWA
WITH THE FRONT. WENT AHEAD WITH 80 TO 100 POPS ALONG AND BEHIND
THE FRONT THIS EVENING AND OVERNIGHT AS A RESULT.
THE HIGHEST RAINFALL AMOUNTS ARE GENERALLY EXPECTED TO REMAIN
NORTH OF INTERSTATE 20 DUE TO THE BETTER UPPER LEVEL SUPPORT/LIFT
FROM THE LEAD SHORTWAVE TROUGH AS MENTIONED ABOVE. THESE LOCATIONS
ARE LIKELY TO SEE A QUARTER TO ONE HALF INCH OF RAIN...WITH
ISOLATED HIGHER AMOUNTS...BY MONDAY MORNING. SOME LIGHT
PRECIPITATION WILL LIKELY PERSIST BEHIND THE COLD
FRONT...PRIMARILY BECAUSE THE COLD AIR BEHIND THE FRONT STARTS OFF
SHALLOW IN NATURE...ALLOWING FRONTOGENETIC FORCING AND WEAK
ISENTROPIC LIFT TO PERSIST UNTIL DEEPER COLD AIR ARRIVES.
UNFORTUNATELY...SUB-FREEZING AIR WAS NOT VERY FAR AWAY EARLY THIS
AFTERNOON. THE SURFACE 32 DEGREE F ISOTHERM WAS LOCATED FROM
CANADIAN TEXAS TO WATONGA OKLAHOMA AT 3 PM CST. IT IS POSSIBLE
THAT LIGHT PRECIPITATION WILL BE ONGOING AS TEMPERATURES FALL
BELOW FREEZING BEHIND THE COLD FRONT TONIGHT ACROSS PARTS OF NORTH
TEXAS LATE TONIGHT INTO EARLY TOMORROW MORNING.
LATEST MODEL GUIDANCE INDICATES THAT LOCATIONS ALONG AND NORTHWEST
OF A LINE FROM BRECKENRIDGE TO DECATUR TO SHERMAN HAVE THE BEST
CHANCE AT SEEING SOME MEASURABLE RAINFALL WITH SUB-FREEZING
TEMPERATURES BEFORE SUNRISE MONDAY...SO WENT AHEAD AND MENTIONED A
CHANCE OF FREEZING RAIN FOR THESE AREAS AFTER MIDNIGHT TONIGHT.
AFTER SUNRISE MONDAY...DEEPER COLD AIR ARRIVES...AND WILL
EVENTUALLY LEAD TO THE ATMOSPHERE DRYING OUT...BRINGING AND END TO
PRECIPITATION FROM NORTHWEST TO SOUTHEAST. ANY ONGOING
PRECIPITATION MAY TRANSITION FROM LIGHT FREEZING RAIN TO LIGHT
SLEET OR FREEZING DRIZZLE BEFORE DISSIPATING MONDAY MORNING.
WHETHER FREEZING DRIZZLE OR LIGHT SLEET OCCURS DEPENDS PRIMARILY
ON HOW LONG SATURATION AND LIFT IS MAINTAINED ALOFT. THE NAM
INDICATES MID-LEVEL SATURATION AND WEAK LIFT PERSISTING THROUGH
18Z WHILE THE GFS IS MORE AGGRESSIVE WITH MID-LEVEL SUBSIDENCE
BEHIND THE LEAD SHORTWAVE AND DRIES THINGS OUT ALOFT AFTER 12Z.
EITHER WAY...NO SIGNIFICANT ACCUMULATION OF SLEET OR FREEZING RAIN
IS EXPECTED AS ONLY VERY LIGHT PRECIPITATION IS EXPECTED TO
PERSIST BEHIND THE COLD FRONT. A VERY THIN GLAZE OF ICE IS
POSSIBLE FOR AREAS ALONG AND NORTHWEST OF A LINE FROM CISCO TO
DENTON TO SHERMAN BEFORE PRECIPITATION ENDS MONDAY MORNING.
OVERALL...THINK THAT THE IMPACTS FROM ANY LIGHT FREEZING
RAIN/SLEET THAT FALLS WILL BE LIMITED. WARM TEMPERATURES OVER THE
PAST COUPLE OF DAYS HAVE LEFT GROUND TEMPERATURES WELL ABOVE
FREEZING. TEMPERATURES ARE ONLY EXPECTED TO FALL INTO THE 29 TO 32
DEGREE RANGE EARLY MONDAY MORNING. EVEN IF GROUND TEMPERATURES
WERE COOLER...EXPERIENCE FROM OTHER "NEAR FREEZING" RAIN EVENTS
THIS SEASON INDICATES THAT ICY ACCUMULATIONS TYPICALLY OCCUR WITH
TEMPERATURES BELOW 29 DEGREES. AS A RESULT...THINK THAT THERE WILL
BE NO ICE ACCUMULATIONS ON AREA ROADWAYS THAT ARE IN CONTACT WITH
THE GROUND. THE PRIMARY CONCERN IN TERMS OF IMPACTS WILL BE TO
BRIDGES AND OVERPASSES. NORTH WINDS ARE EXPECTED TO PICK UP TO 20
MPH GUSTING TO 30 MPH BEHIND THE FRONT. THIS WILL RESULT IN THE
RAPID COOLING OF BRIDGES AND OVERPASSES...ALLOWING FOR THE
POTENTIAL FOR A LIGHT GLAZE OF ICE TO DEVELOP IF PRECIPITATION
PERSISTS BEHIND THE FRONT EARLY TOMORROW MORNING. BECAUSE
CONFIDENCE IN PRECIPITATION WELL BEHIND THE FRONT IS SOMEWHAT
LOW...AND BECAUSE ANTICIPATED IMPACTS ARE EXPECTED TO BE
MINOR...WILL NOT ISSUE A WINTER WEATHER ADVISORY FOR LOCATIONS
NORTHWEST OF THE DFW AREA AT THIS TIME. CONFIDENCE IN MINOR TO NO
IMPACTS DUE TO ICING IS FAIRLY HIGH AT THIS TIME.
MONDAY AFTERNOON...LARGE SCALE SUBSIDENCE AND PERSISTENT
COLD...DRY AIR ADVECTION WILL CAUSE ALL PRECIPITATION TO END
ACROSS THE REGION FROM NORTHWEST TO SOUTHEAST BY THE MID-AFTERNOON
HOURS ON MONDAY. WE MAY EVEN SEE THE CLOUDS CLEAR OUT MONDAY
AFTERNOON FOR A FEW HOURS OF SUNSHINE BEFORE WE CLOUD BACK UP AS
THE SECOND SHORTWAVE TROUGH MOVES OVER THE REGION MONDAY NIGHT.
ALL AREAS ARE EXPECTED TO CLIMB ABOVE FREEZING ON MONDAY...SO ANY
GLAZING OF ICE SHOULD DISSIPATE FAIRLY QUICKLY...THROUGH MELTING
OR SUBLIMATION DUE TO THE BREEZY NORTH WINDS.
THE SECOND SHORTWAVE TROUGH IS EXPECTED TO MOVE OVER THE REGION
MONDAY NIGHT...SPREADING STRONG LIFT OVER THE REGION. THIS TROUGH
IS EXPECTED TO MOVE FARTHER SOUTH THAN THE LEAD TROUGH...AND
SHOULD RESULT IN STRONGER LARGE SCALE LIFT OVER THE CWA.
HOWEVER...THERE WILL NOT BE MUCH MOISTURE LEFT TO LIFT BY THE TIME
THIS STRONGER LIFT ARRIVES MONDAY NIGHT. MODELS CONSISTENTLY
INDICATE THAT THIS LIFT WILL CAUSE SKIES TO BECOME CLOUDY
AGAIN...WITH THE 700 TO 500 MB LAYER BECOMING SATURATED.
HOWEVER...THE AIR BELOW 700 MB IS EXPECTED TO BE QUITE DRY...SO IT
WILL PROBABLY BE DIFFICULT TO GET PRECIPITATION DOWN TO THE
SURFACE. THE ATMOSPHERE IN GENERAL IS COLDER...SO ANY
PRECIPITATION THAT MAKES IT TO THE GROUND WOULD LIKELY BE IN THE
FORM OF SNOW. HOWEVER...WITH VERY HIGH CONFIDENCE IN DRY AIR BELOW
700 MB...THINK THAT WE WILL STRUGGLE TO SEE MUCH MORE THAN
FLURRIES FROM THIS LIFT MONDAY NIGHT INTO TUESDAY MORNING. SIMPLY
KEPT THE WIDESPREAD 20 POPS FROM THE PREVIOUS FORECAST DUE TO THE
PRESENCE OF THIS STRONG MID-LEVEL LIFT IN COLD AIR. 20 POPS MAY BE
OVERDOING IT THOUGH...HOWEVER CANNOT RULE OUT THE CHANCE OF LIGHT
SNOW FALLING JUST ABOUT ANYWHERE ACROSS THE CWA MONDAY NIGHT/EARLY
TUESDAY MORNING. NO IMPACTS ARE EXPECTED EVEN IF LIGHT SNOW FALLS
OVER MOST OF THE AREA.
MEASURABLE SNOWFALL APPEARS TO BE MOST LIKELY WEST OF MINERAL
WELLS AFTER MIDNIGHT TUESDAY MORNING. THE GFS AND NAM BOTH HINT AT
ONE STRONGER BAND OF FRONTOGENETICALLY DRIVEN SNOWFALL DEVELOPING
FROM WEST CENTRAL TEXAS...EAST TO MINERAL WELLS OR STEPHENVILLE
DURING THIS TIME. EVEN IF THIS BAND IS REALIZED...IT WILL STILL
HAVE TO CONTEND WITH THE LOW-LEVEL DRY AIR IN PLACE...SO SNOWFALL
TOTALS SHOULD REMAIN BELOW ONE HALF INCH. THE MOST LIKELY OUTCOME
FOR MONDAY NIGHT INTO TUESDAY MORNING IS THAT WE REMAIN TOO DRY TO
SEE ANY SNOWFALL ACROSS THE REGION. HOWEVER...CANNOT IGNORE THE
SIGNALS FOR A SMALL SNOW BAND DEVELOPING IN THE 12Z GFS AND
NAM...SO WENT WITH A 30 POP WEST OF MINERAL WELLS AND STEPHENVILLE
FOR EARLY TUESDAY MORNING.
TUESDAY AFTERNOON THROUGH THURSDAY...STRONG SUBSIDENCE SHOULD
RESULT IN MOSTLY CLEAR SKIES ACROSS THE REGION BY SUNSET TUESDAY.
MOSTLY CLEAR SKIES WILL BE THE GENERAL RULE FOR WEDNESDAY AND
THURSDAY UNTIL THE APPROACH OF ANOTHER UPPER LEVEL STORM SYSTEM
BRINGS CLOUDS AND PRECIPITATION BACK INTO THE FORECAST FOR THE END
OF THE WEEK HEADED INTO THE WEEKEND.
FRIDAY THROUGH SUNDAY...FOR NOW HAVE SOME BROAD BRUSHED RAIN
CHANCES IN THE FORECAST TO ACCOUNT FOR RETURNING GULF MOISTURE AND
MODEL TO MODEL UNCERTAINTY REGARDING THE TIMING OF THE UPPER LEVEL
STORM SYSTEM. OUR BEST RAIN CHANCES LOOK TO BE SATURDAY NIGHT INTO
SUNDAY FOR NOW...BUT THIS WILL LIKELY CHANGE AS MODELS DO A BETTER
JOB OF RESOLVING THE TIMING OF THE UPPER LEVEL STORM SYSTEM. ALL
PRECIPITATION IS EXPECTED TO REMAIN IN THE LIQUID/RAIN FORM FOR
NEXT WEEKEND AT THIS TIME.
CAVANAUGH
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 35 41 31 49 34 / 100 30 20 10 5
WACO, TX 41 44 31 48 32 / 100 40 20 20 0
PARIS, TX 34 38 26 46 30 / 100 50 20 10 5
DENTON, TX 32 40 29 48 30 / 100 30 20 10 0
MCKINNEY, TX 34 39 28 47 30 / 100 40 20 10 5
DALLAS, TX 36 41 31 49 35 / 100 30 20 10 5
TERRELL, TX 39 41 29 47 31 / 100 40 20 10 5
CORSICANA, TX 43 43 30 47 33 / 100 50 20 10 5
TEMPLE, TX 45 45 31 48 31 / 90 50 20 20 0
MINERAL WELLS, TX 32 42 30 49 31 / 100 30 20 20 5
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
58/84
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
816 PM CST SUN FEB 15 2015
.AVIATION...
THE 02Z /8PM/ SURFACE ANALYSIS INDCITED THAT EH FRONT IS MOVING A
LITTLE FASTER TO THE SOUTHEAST THAN WE HAD EARLIER FORECAST. GUSTY
NORTHERLY WINDS HAVE MOVED INTO KRPH /GRAHAM/ AND KBKD /BRECKENRIDGE/
AS OF 02Z. EXPECT THE FRONT TO MOVE INTO THE METROPLEX AROUND 07Z
AS INDICATED BY THE 00Z RUNS OF THE RAP AND NAM AND THE 23Z RUN OF
THE HRRR.
58
&&
.PREV DISCUSSION... /ISSUED 344 PM CST SUN FEB 15 2015/
EARLY AFTERNOON WATER VAPOR SATELLITE IMAGERY SHOWED A SHORTWAVE
TROUGH OVER THE UTAH/WYOMING/COLORADO BORDERS...MOVING SOUTHEAST.
WATER VAPOR IMAGERY ALSO SHOWED A COMPACT CUT OFF LOW WHICH WAS
NEARLY STATIONARY OVER BAJA CALIFORNIA. 12Z SUBJECTIVE UPPER AIR
ANALYSIS SHOWED A LARGE AND INTENSE UPPER TROUGH OVER THE
NORTHEASTERN CONUS WITH UPPER LEVEL RIDGING OVER THE WESTERN COAST
OF NORTH AMERICA. THE STRONG UPPER TROUGH OVER THE NORTHEASTERN
CONUS HAD USHERED IN SOME VERY COLD AIR INTO THE CONUS EXTENDING
FROM THE NORTHERN PLAINS...SOUTHEAST TO SOUTH CAROLINA AT THE 850
MB LEVEL. SURFACE ANALYSIS INDICATED THAT A SHALLOW WEDGE OF THIS
COLD AIR HAD MADE IT AS FAR SOUTHWEST AS OKLAHOMA INTO NORTHERN
MISSISSIPPI. 19Z SUBJECTIVE REGIONAL SURFACE ANALYSIS SHOWED A
DEEPENING CYCLONE CENTERED OVER SOUTHEASTERN NEW MEXICO. A STRONG
BAROCLINIC ZONE EXTENDING EAST FROM THIS LOW WAS ANALYZED ACROSS
THE SOUTHERN TEXAS PANHANDLE...THEN ALONG THE RED RIVER TO SHERMAN
BEFORE DIPPING SOUTHEAST ACROSS EAST TEXAS AND CENTRAL LOUISIANA.
THE TEMPERATURE GRADIENT ON EITHER SIDE OF THIS BAROCLINIC ZONE
WAS FAIRLY IMPRESSIVE WITH A 38 DEGREE TEMPERATURE OBSERVED AT
AMARILLO AND A 75 DEGREE TEMPERATURE OBSERVED AT LUBBOCK.
ACROSS NORTH TEXAS...TEMPERATURES WERE GENERALLY OBSERVED IN THE
UPPER 60S TO LOWER 70S...EXCEPT FOR LOCATIONS ALONG AND NORTH OF A
SHERMAN TO EMORY LINE...WHERE TEMPERATURES WERE IN THE LOWER TO
MID 50S. THIS LINE REPRESENTS THE BAROCLINIC ZONE DESCRIBED
ABOVE...WHICH WAS BEHAVING LIKE A WARM FRONT EARLY THIS AFTERNOON
AND WAS SLOWLY ADVANCING NORTH TOWARDS THE RED RIVER. TO THE
SOUTHWEST OF THIS BOUNDARY...REGIONAL RADARS SHOWED SCATTERED RAIN
SHOWERS OVER MOST OF NORTH AND CENTRAL TEXAS. WHILE THE RADAR
LOOKS VERY BUSY...NOT MANY SITES WERE ACTUALLY REPORTING
PRECIPITATION AS OF 300 PM CST. THE 12Z FWD RAOB WAS FAIRLY
DRY...SO THESE MID-LEVEL BASED RAIN SHOWERS ARE ESSENTIALLY
WORKING TO SATURATE THE ATMOSPHERE FROM THE TOP DOWN THIS
AFTERNOON. EXPECT THAT MORE AND MORE RAIN WILL REACH THE SURFACE
AS THIS PROCESS CONTINUES THROUGH SUNSET. HAVE THE HIGHEST POPS
WEST OF INTERSTATE 35 THROUGH SUNSET ASSUMING IT WILL BE DIFFICULT
TO GET MEASURABLE RAINFALL FARTHER EAST BEFORE 00Z...SIMPLY
BECAUSE IT HAS NOT BEEN RAINING EAST OF INTERSTATE 35 AS LONG AS
IT HAS BEEN TO THE WEST.
THIS EVENING...THE UT/WY/CO SHORTWAVE TROUGH IS EXPECTED TO
CONTINUE TO DIG SOUTHEAST BEFORE MOVING EAST OVER OKLAHOMA
TOMORROW MORNING. THE SHORTWAVE TROUGH IS EXPECTED TO REMAIN NORTH
OF THE CWA PRIMARILY BECAUSE OF THE INFLUENCE OF A STRONGER
SHORTWAVE TROUGH THAT IS EXPECTED TO DIG SOUTH OVER THE CONUS
ROCKIES THROUGHOUT THE DAY ON MONDAY. THIS SECOND TROUGH IS
EXPECTED TO KICK THE LEAD TROUGH OFF TO THE EAST-NORTHEAST...AND
SHOULD ALSO CAUSE THE BAJA UPPER LOW TO MOVE NORTHEAST WHILE
WEAKENING/BECOMING SHEARED APART.
WHAT ALL OF THIS UPPER LEVEL ACTIVITY SHOULD MEAN FOR US IS THAT
THE BEST LARGE SCALE FORCING FOR ASCENT SHOULD REMAIN OVER THE
NORTHERN PORTIONS OF THE CWA...RESULTING IN HIGHER RAINFALL
AMOUNTS HOLDING NORTH OF INTERSTATE 20 OVER THE NEXT 24 HOURS. THIS
UPPER LEVEL ACTIVITY WILL ALSO SEND THE SURFACE LOW EAST...AND THE
ACCOMPANYING BAROCLINIC ZONE SHOULD SURGE SOUTH AS A STRONG COLD
FRONT IN THE WAKE OF THE SURFACE LOW. AS MENTIONED ABOVE...THE
BAROCLINICITY ASSOCIATED WITH THIS FRONT IS ALREADY QUITE
HIGH...SO EXPECT STRONG FRONTOGENETIC FORCING ALONG AND BEHIND THE
COLD FRONT AS IT SURGES SOUTH ACROSS THE CWA THIS EVENING AND
OVERNIGHT. ASSUMING THE ATMOSPHERE DOES BECOME SATURATED FROM THE
MID-LEVELS DOWN TO THE SURFACE DUE TO ONGOING ELEVATED RAIN
SHOWERS...EXPECT THAT MOST LOCATIONS WILL RECEIVE MEASURABLE
RAINFALL AS THE FRONT MOVES ACROSS THE REGION. THE STRENGTH OF THE
BAROCLINICITY ALONG THE BOUNDARY RIGHT NOW...COMBINED WITH THE
WIDESPREAD RADAR RETURNS OVER MOST OF THE CWA AT THE TIME OF THIS
DISCUSSION INCREASES CONFIDENCE IN RAIN CHANCES ACROSS THE CWA
WITH THE FRONT. WENT AHEAD WITH 80 TO 100 POPS ALONG AND BEHIND
THE FRONT THIS EVENING AND OVERNIGHT AS A RESULT.
THE HIGHEST RAINFALL AMOUNTS ARE GENERALLY EXPECTED TO REMAIN
NORTH OF INTERSTATE 20 DUE TO THE BETTER UPPER LEVEL SUPPORT/LIFT
FROM THE LEAD SHORTWAVE TROUGH AS MENTIONED ABOVE. THESE LOCATIONS
ARE LIKELY TO SEE A QUARTER TO ONE HALF INCH OF RAIN...WITH
ISOLATED HIGHER AMOUNTS...BY MONDAY MORNING. SOME LIGHT
PRECIPITATION WILL LIKELY PERSIST BEHIND THE COLD
FRONT...PRIMARILY BECAUSE THE COLD AIR BEHIND THE FRONT STARTS OFF
SHALLOW IN NATURE...ALLOWING FRONTOGENETIC FORCING AND WEAK
ISENTROPIC LIFT TO PERSIST UNTIL DEEPER COLD AIR ARRIVES.
UNFORTUNATELY...SUB-FREEZING AIR WAS NOT VERY FAR AWAY EARLY THIS
AFTERNOON. THE SURFACE 32 DEGREE F ISOTHERM WAS LOCATED FROM
CANADIAN TEXAS TO WATONGA OKLAHOMA AT 3 PM CST. IT IS POSSIBLE
THAT LIGHT PRECIPITATION WILL BE ONGOING AS TEMPERATURES FALL
BELOW FREEZING BEHIND THE COLD FRONT TONIGHT ACROSS PARTS OF NORTH
TEXAS LATE TONIGHT INTO EARLY TOMORROW MORNING.
LATEST MODEL GUIDANCE INDICATES THAT LOCATIONS ALONG AND NORTHWEST
OF A LINE FROM BRECKENRIDGE TO DECATUR TO SHERMAN HAVE THE BEST
CHANCE AT SEEING SOME MEASURABLE RAINFALL WITH SUB-FREEZING
TEMPERATURES BEFORE SUNRISE MONDAY...SO WENT AHEAD AND MENTIONED A
CHANCE OF FREEZING RAIN FOR THESE AREAS AFTER MIDNIGHT TONIGHT.
AFTER SUNRISE MONDAY...DEEPER COLD AIR ARRIVES...AND WILL
EVENTUALLY LEAD TO THE ATMOSPHERE DRYING OUT...BRINGING AND END TO
PRECIPITATION FROM NORTHWEST TO SOUTHEAST. ANY ONGOING
PRECIPITATION MAY TRANSITION FROM LIGHT FREEZING RAIN TO LIGHT
SLEET OR FREEZING DRIZZLE BEFORE DISSIPATING MONDAY MORNING.
WHETHER FREEZING DRIZZLE OR LIGHT SLEET OCCURS DEPENDS PRIMARILY
ON HOW LONG SATURATION AND LIFT IS MAINTAINED ALOFT. THE NAM
INDICATES MID-LEVEL SATURATION AND WEAK LIFT PERSISTING THROUGH
18Z WHILE THE GFS IS MORE AGGRESSIVE WITH MID-LEVEL SUBSIDENCE
BEHIND THE LEAD SHORTWAVE AND DRIES THINGS OUT ALOFT AFTER 12Z.
EITHER WAY...NO SIGNIFICANT ACCUMULATION OF SLEET OR FREEZING RAIN
IS EXPECTED AS ONLY VERY LIGHT PRECIPITATION IS EXPECTED TO
PERSIST BEHIND THE COLD FRONT. A VERY THIN GLAZE OF ICE IS
POSSIBLE FOR AREAS ALONG AND NORTHWEST OF A LINE FROM CISCO TO
DENTON TO SHERMAN BEFORE PRECIPITATION ENDS MONDAY MORNING.
OVERALL...THINK THAT THE IMPACTS FROM ANY LIGHT FREEZING
RAIN/SLEET THAT FALLS WILL BE LIMITED. WARM TEMPERATURES OVER THE
PAST COUPLE OF DAYS HAVE LEFT GROUND TEMPERATURES WELL ABOVE
FREEZING. TEMPERATURES ARE ONLY EXPECTED TO FALL INTO THE 29 TO 32
DEGREE RANGE EARLY MONDAY MORNING. EVEN IF GROUND TEMPERATURES
WERE COOLER...EXPERIENCE FROM OTHER "NEAR FREEZING" RAIN EVENTS
THIS SEASON INDICATES THAT ICY ACCUMULATIONS TYPICALLY OCCUR WITH
TEMPERATURES BELOW 29 DEGREES. AS A RESULT...THINK THAT THERE WILL
BE NO ICE ACCUMULATIONS ON AREA ROADWAYS THAT ARE IN CONTACT WITH
THE GROUND. THE PRIMARY CONCERN IN TERMS OF IMPACTS WILL BE TO
BRIDGES AND OVERPASSES. NORTH WINDS ARE EXPECTED TO PICK UP TO 20
MPH GUSTING TO 30 MPH BEHIND THE FRONT. THIS WILL RESULT IN THE
RAPID COOLING OF BRIDGES AND OVERPASSES...ALLOWING FOR THE
POTENTIAL FOR A LIGHT GLAZE OF ICE TO DEVELOP IF PRECIPITATION
PERSISTS BEHIND THE FRONT EARLY TOMORROW MORNING. BECAUSE
CONFIDENCE IN PRECIPITATION WELL BEHIND THE FRONT IS SOMEWHAT
LOW...AND BECAUSE ANTICIPATED IMPACTS ARE EXPECTED TO BE
MINOR...WILL NOT ISSUE A WINTER WEATHER ADVISORY FOR LOCATIONS
NORTHWEST OF THE DFW AREA AT THIS TIME. CONFIDENCE IN MINOR TO NO
IMPACTS DUE TO ICING IS FAIRLY HIGH AT THIS TIME.
MONDAY AFTERNOON...LARGE SCALE SUBSIDENCE AND PERSISTENT
COLD...DRY AIR ADVECTION WILL CAUSE ALL PRECIPITATION TO END
ACROSS THE REGION FROM NORTHWEST TO SOUTHEAST BY THE MID-AFTERNOON
HOURS ON MONDAY. WE MAY EVEN SEE THE CLOUDS CLEAR OUT MONDAY
AFTERNOON FOR A FEW HOURS OF SUNSHINE BEFORE WE CLOUD BACK UP AS
THE SECOND SHORTWAVE TROUGH MOVES OVER THE REGION MONDAY NIGHT.
ALL AREAS ARE EXPECTED TO CLIMB ABOVE FREEZING ON MONDAY...SO ANY
GLAZING OF ICE SHOULD DISSIPATE FAIRLY QUICKLY...THROUGH MELTING
OR SUBLIMATION DUE TO THE BREEZY NORTH WINDS.
THE SECOND SHORTWAVE TROUGH IS EXPECTED TO MOVE OVER THE REGION
MONDAY NIGHT...SPREADING STRONG LIFT OVER THE REGION. THIS TROUGH
IS EXPECTED TO MOVE FARTHER SOUTH THAN THE LEAD TROUGH...AND
SHOULD RESULT IN STRONGER LARGE SCALE LIFT OVER THE CWA.
HOWEVER...THERE WILL NOT BE MUCH MOISTURE LEFT TO LIFT BY THE TIME
THIS STRONGER LIFT ARRIVES MONDAY NIGHT. MODELS CONSISTENTLY
INDICATE THAT THIS LIFT WILL CAUSE SKIES TO BECOME CLOUDY
AGAIN...WITH THE 700 TO 500 MB LAYER BECOMING SATURATED.
HOWEVER...THE AIR BELOW 700 MB IS EXPECTED TO BE QUITE DRY...SO IT
WILL PROBABLY BE DIFFICULT TO GET PRECIPITATION DOWN TO THE
SURFACE. THE ATMOSPHERE IN GENERAL IS COLDER...SO ANY
PRECIPITATION THAT MAKES IT TO THE GROUND WOULD LIKELY BE IN THE
FORM OF SNOW. HOWEVER...WITH VERY HIGH CONFIDENCE IN DRY AIR BELOW
700 MB...THINK THAT WE WILL STRUGGLE TO SEE MUCH MORE THAN
FLURRIES FROM THIS LIFT MONDAY NIGHT INTO TUESDAY MORNING. SIMPLY
KEPT THE WIDESPREAD 20 POPS FROM THE PREVIOUS FORECAST DUE TO THE
PRESENCE OF THIS STRONG MID-LEVEL LIFT IN COLD AIR. 20 POPS MAY BE
OVERDOING IT THOUGH...HOWEVER CANNOT RULE OUT THE CHANCE OF LIGHT
SNOW FALLING JUST ABOUT ANYWHERE ACROSS THE CWA MONDAY NIGHT/EARLY
TUESDAY MORNING. NO IMPACTS ARE EXPECTED EVEN IF LIGHT SNOW FALLS
OVER MOST OF THE AREA.
MEASURABLE SNOWFALL APPEARS TO BE MOST LIKELY WEST OF MINERAL
WELLS AFTER MIDNIGHT TUESDAY MORNING. THE GFS AND NAM BOTH HINT AT
ONE STRONGER BAND OF FRONTOGENETICALLY DRIVEN SNOWFALL DEVELOPING
FROM WEST CENTRAL TEXAS...EAST TO MINERAL WELLS OR STEPHENVILLE
DURING THIS TIME. EVEN IF THIS BAND IS REALIZED...IT WILL STILL
HAVE TO CONTEND WITH THE LOW-LEVEL DRY AIR IN PLACE...SO SNOWFALL
TOTALS SHOULD REMAIN BELOW ONE HALF INCH. THE MOST LIKELY OUTCOME
FOR MONDAY NIGHT INTO TUESDAY MORNING IS THAT WE REMAIN TOO DRY TO
SEE ANY SNOWFALL ACROSS THE REGION. HOWEVER...CANNOT IGNORE THE
SIGNALS FOR A SMALL SNOW BAND DEVELOPING IN THE 12Z GFS AND
NAM...SO WENT WITH A 30 POP WEST OF MINERAL WELLS AND STEPHENVILLE
FOR EARLY TUESDAY MORNING.
TUESDAY AFTERNOON THROUGH THURSDAY...STRONG SUBSIDENCE SHOULD
RESULT IN MOSTLY CLEAR SKIES ACROSS THE REGION BY SUNSET TUESDAY.
MOSTLY CLEAR SKIES WILL BE THE GENERAL RULE FOR WEDNESDAY AND
THURSDAY UNTIL THE APPROACH OF ANOTHER UPPER LEVEL STORM SYSTEM
BRINGS CLOUDS AND PRECIPITATION BACK INTO THE FORECAST FOR THE END
OF THE WEEK HEADED INTO THE WEEKEND.
FRIDAY THROUGH SUNDAY...FOR NOW HAVE SOME BROAD BRUSHED RAIN
CHANCES IN THE FORECAST TO ACCOUNT FOR RETURNING GULF MOISTURE AND
MODEL TO MODEL UNCERTAINTY REGARDING THE TIMING OF THE UPPER LEVEL
STORM SYSTEM. OUR BEST RAIN CHANCES LOOK TO BE SATURDAY NIGHT INTO
SUNDAY FOR NOW...BUT THIS WILL LIKELY CHANGE AS MODELS DO A BETTER
JOB OF RESOLVING THE TIMING OF THE UPPER LEVEL STORM SYSTEM. ALL
PRECIPITATION IS EXPECTED TO REMAIN IN THE LIQUID/RAIN FORM FOR
NEXT WEEKEND AT THIS TIME.
CAVANAUGH
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 35 41 31 49 34 / 100 30 20 10 5
WACO, TX 41 44 31 48 32 / 100 40 20 20 0
PARIS, TX 34 38 26 46 30 / 100 50 20 10 5
DENTON, TX 32 40 29 48 30 / 100 30 20 10 0
MCKINNEY, TX 34 39 28 47 30 / 100 40 20 10 5
DALLAS, TX 36 41 31 49 35 / 100 30 20 10 5
TERRELL, TX 39 41 29 47 31 / 100 40 20 10 5
CORSICANA, TX 43 43 30 47 33 / 100 50 20 10 5
TEMPLE, TX 45 45 31 48 31 / 90 50 20 20 0
MINERAL WELLS, TX 32 42 30 49 31 / 100 30 20 20 5
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
58/84
AREA FORECAST DISCUSSION...UPDATED
NWS SAN ANGELO TX
722 PM CST Sun Feb 15 2015
.UPDATE...
Strong cold front has advanced south into our northern counties
and was just north of Sweetwater and Abilene at 715 PM. This
front is making a little faster progress than previously
expected, and the RUC model appears to have the best handle
on the southward progression of this front tonight. Temperatures
behind the front have already dropped into the upper 30s to lower
40s. Rain showers are occurring across the area north of I-20 and
east of an Aspermont to Abilene line. This is where we have the
highest PoPs tonight. Will have a possibility of light rain or
freezing rain across our northern counties by late tonight, as
surface temperatures drop to or just below the freezing mark.
Forecast has been updated for tonight mainly for winds based on
the RUC, and have adjusted temperatures, winds and dewpoints to
bring in line with current/recent trends in the northern part of
our area.
19
&&
.PREV DISCUSSION... /ISSUED 555 PM CST Sun Feb 15 2015/
AVIATION...
/00Z TAFS/
A strong cold front continues to move south into the area this
evening. The front is expected to make it to KABI by 02Z/8PM or
03Z/9PM this evening. Behind it, CIGS are expected to quickly
deteriorate into the MVFR category to around 1500 feet. In
addition, at the KABI terminal, -SHRA or -DZ is expected to
develop after 05Z/11PM tonight, continuing intermittently through
most of the overnight hours. Expect the precipitation to end by
early tomorrow morning, leaving MVFR CIGS behind through most of
the morning before they start to lift for the afternoon hours
tomorrow. Similar conditions expected farther south, minus the
precipitation. The front should be through KSJT and KBBD by
09Z/3AM or 10Z/4AM tonight, possibly a little earlier, and will
check the timing of the front with the next TAF forecast issuance
if the front speeds up. KSOA and KJCT can expect the front an hour
or two later. While there may be some isolated precipitation at
the southern 4 sites, do not think there will be enough to mention
in the TAFs at this time. CIGS should lift at the other sites by
18Z/12PM tomorrow as well. 20
PREV DISCUSSION... /ISSUED 251 PM CST Sun Feb 15 2015/
SHORT TERM...
(Tonight and Tomorrow)
An upper low over the central Baja Peninsula early this afternoon
will weaken as it moves to the east and is sheared into the
southwestern flow aloft of a broad upper trough positioned over
the central CONUS. A cold front associated with the large upper
trough was moving south through the northern Panhandle early this
afternoon and will enter the Big Country late this evening. By
midnight the front should be along the Interstate 20 corridor.
Temperatures for tonight will be slow to drop with temperatures
just reaching the freezing mark over the Big Country around
sunrise. Temperatures will warm quickly after sunrise over the Big
Country with only a few hours of freezing temperatures expected.
Consequently, any light rain and freezing rain mix over the Big
Country will be short-lived and will at most affect only elevated
surfaces for a few hours.
For the remainder of the forecast area south of the Big Country,
morning lows will range from the mid 30s over the central CWA and
the 40s along the Interstate 10 corridor, with any precipitation
falling being in the liquid state. The cold front will push
completely through the forecast area before noon. Rain chances
will end from north to south during the day tomorrow with
afternoon highs reaching the mid 40s over the Big Country and the
upper 40s to around 50 over the southern CWA.
15
LONG TERM...
(Monday night through Sunday)
The shortwave trough currently located over British Columbia will
dive south over the next 24-36 hours, bringing another chance
for light precipitation to the area Monday night into Tuesday
morning. Lift associated with this system does not appear all that
favorable for a significant precipitation event. However, with
additional mesoscale forcing, there should be enough ascent to
generate light precipitation across the area, mainly beginning
after midnight. Point soundings indicate cooling aloft, eroding
the warm nose by the onset of precipitation. The question is how
much dry air will need to be moistened in the lowest few
kilometers. The GFS soundings indicate that significant moistening
will need to take place, while the NAM keeps the boundary layer
nearly saturated. The latter seems to represent an observed bias
with the NAM.
Either way, after midnight, light snow (possibly mixed with some
light sleet) will be possible across much of the CWA, with light
rain confined to the northwest Hill Country. This trend is
expected to continue into Tuesday morning, with precipitation
coming to an end by midday. Accumulations are expected to be minor
(at best) with this system. A dusting of snow is possible, mainly
north of a Sterling City to Cross Plains line, with little to no
accumulations elsewhere. Temperatures are forecast to drop into
the upper 20s, but limited QPF will zap any potential for heavier
snow.
Skies will clear as we move into Tuesday afternoon/evening. Expect
afternoon temperatures to warm into the upper 40s with winds
becoming light from the west/southwest. These light winds, dry
air, and clear skies will allow temperatures to fall into the
upper 20s and lower 30s by Wednesday morning. These cold
temperatures will be a distant memory by the afternoon, as
temperatures rebound back into the lower 60s across most of West
Central TX. The warming trend will continue on Thursday, with
highs in the mid/upper 60s.
We continue to monitor a pattern change heading into the weekend.
The West Coast ridges persists, but the ridge axis shifts back
to the west as a potent trough digs south along the Great Divide.
The flow aloft becomes briefly quasi-zonal by Friday, backing to
the southwest over the weekend as the aforementioned trough digs
toward the Four Corners. This is setting the stage for another
dump of cold air across the Plains. Just how cold remains in
question, but there is good agreement in the medium range models
that a cold front will move across the area by Sunday.
Ahead of this front, the models are developing light QPF across
central TX in response to warm advection and an open gulf. Broad
isentropic ascent is expected across the region Friday and
Saturday. Low PoPs were maintained for Saturday, but may need to
added for some areas on Friday if the latest trends hold. The 12z
ECMWF is much more aggressive with the weekend cold front compared
to the GFS/DGEX, but all of these models develop some QPF across
the area at some point with this system. We`ll continue to monitor
this system as the models zero in on a favored solution.
Johnson
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 32 46 27 49 33 / 50 20 30 20 5
San Angelo 36 50 28 50 30 / 30 20 20 20 0
Junction 48 50 31 51 30 / 20 20 20 20 5
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
YOU CAN SEE AN ILLUSTRATED VERSION OF THIS FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML
AREA FORECAST DISCUSSION
NWS TUCSON AZ
914 PM MST SUN FEB 15 2015
.SYNOPSIS...EXPECT ISOLATED TO SCATTERED SHOWERS THROUGH MONDAY
EVENING. THE BEST CHANCE FOR HEAVIER RAINFALL WILL BE SOUTH OF
TUCSON. DRY CONDITIONS WITH WELL ABOVE NORMAL DAYTIME TEMPERATURES
WILL THEN OCCUR TUESDAY INTO NEXT WEEKEND.
&&
.DISCUSSION...EARLIER THIS EVENING SHOWERS ALONG WITH A FEW
THUNDERSTORMS DEVELOPED MOSTLY OVER SANTA CRUZ COUNTY WITH A COUPLE
OF RAIN GAUGES ALONG THE IMMEDIATE BORDER WITH MEXICO THAT INDICATED
AMOUNTS BETWEEN 0.70-0.90 INCHES. AS A RESULT...A SMALL STREAM FLOOD
ADVISORY WAS ISSUED FOR EXTREME SOUTHERN SANTA CRUZ COUNTY FROM
AROUND RUBY THROUGH NOGALES TO THE BORDER WITH COCHISE COUNTY. THE
ADVISORY HAS LONG SINCE EXPIRED AT 7 PM MST WITH RECENT RADAR MOSAIC
INDICATING THAT THE SHOWERS HAVE BEEN STEADILY DIMINISHING DURING
THE PAST HOUR AND A HALF AS THEY MOVE SLOWLY TO THE SOUTH WITH THE
INFLUENCE OF THE APPROACHING UPSTREAM SHORTWAVE FROM THE FOUR
CORNERS AREA. AS THIS FEATURE CONTINUES TO MOVE SOUTH IT WILL PUSH
THE BAJA LOW FARTHER SOUTH THROUGH THE DAY ON MONDAY.
IR SATELLITE IMAGERY SHOWS EXTENSIVE CLOUDINESS ASSOCIATED WITH THE
LOW PRESSURE SYSTEM THAT IS CURRENTLY SPINNING OVER THE CENTRAL GULF
OF CALIFORNIA...COVERING A LARGE PART OF NORTHERN MEXICO...SOUTHEAST
ARIZONA AND EASTWARD ACROSS MUCH OF NEW MEXICO AND WEST TEXAS.
LIGHTNING ACTIVITY ASSOCIATED WITH THE LOW HAS BEEN DECREASING FOR
THE PAST COUPLE OF HOURS...WITH MOST OF THE LIGHTNING STRIKES WELL
TO OUR SOUTH NEAR HERMOSILLO, MEXICO. LATEST HRRR AND U OF A WRF/NAM
ARE BOTH INDICATING THAT THE SHOWERS WILL CONTINUE TO MOVE FARTHER
SOUTH INTO MEXICO OVERNIGHT. WILL MAKE SOME MINOR TWEAKS TO THE POP
GRIDS TO REFLECT THIS NOTION...BUT WILL STILL MAINTAIN A SMALL
THREAT ALONG THE MEXICAN BORDER FROM AROUND THE NOGALES AREA TO THE
BORDER WITH NEW MEXICO.
AS OF 04Z (9 PM MST)...TEMPERATURES ACROSS THE REGION RANGED FROM
THE LOWER 50S TO THE LOWER 60S WITH THE TUCSON INTL AIRPORT
REPORTING A TEMP OF 62 DEGS AFTER AN AFTERNOON HIGH OF 71 DEGS...
WHICH WAS 3 DEGS ABOVE NORMAL FOR THIS DATE. INHERITED OVERNIGHT LOW
TEMPS SEEM TO BE ON TRACK...BUT WILL MAKE SOME ADJUSTMENTS TO THE
SHORT TERM HOURLY TEMP GRIDS TO REFLECT RECENT TRENDS.
FOR DETAILS REGARDING THE FORECAST BEYOND TONIGHT...PLEASE REFER TO
THE PREVIOUS DISCUSSION BELOW.
&&
.AVIATION...VALID THRU 17/06Z.
ISOLATED TO SCATTERED SHOWERS WILL OCCUR INTO MONDAY AFTERNOON.
THERE IS ALSO A SLIGHT CHANCE OF -TSRA SOUTH TO SOUTHEAST OF KTUS
MAINLY MONDAY AFTERNOON. OTHERWISE...CLOUD DECKS WILL GENERALLY
RANGE FROM 6K-12K FT AGL. SURFACE WIND EAST OF KTUS EARLY THIS
EVENING AND MONDAY AFTERNOON WILL BE WLY/NWLY AT 12-22 KTS WITH
GUSTS OF 25-30 KTS. THE STRONGEST WIND WILL OCCUR NE OF KTUS AND
ESPECIALLY IN THE VICINITY OF KSAD. ELSEWHERE...SURFACE WIND WILL
MAINLY BE LESS THAN 10 KTS THRU THE PERIOD. AVIATION DISCUSSION NOT
UPDATED FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...EXPECT ISOLATED TO SCATTERED SHOWERS THROUGH MONDAY
EVENING. THERE IS ALSO A SLIGHT CHANCE OF THUNDERSTORMS MAINLY
MONDAY AFTERNOON AND EVENING...SOUTH TO SOUTHEAST OF TUCSON. DRY
CONDITIONS WILL THEN PREVAIL TUESDAY INTO NEXT WEEKEND. GUSTY WEST
TO NORTHWEST WINDS WILL OCCUR MONDAY AFTERNOON ESPECIALLY EAST OF
TUCSON. THEREAFTER...EXPECT GENERALLY LIGHT TERRAIN DRIVEN WINDS
DURING MUCH OF THE REST OF THE WEEK.
&&
.PREV DISCUSSION...THE UPPER LOW WILL MOVE EWD INTO THE CENTRAL GULF
OF CALIFORNIA TONIGHT...THEN WEAKEN RAPIDLY OVER SONORA MEXICO MON.
THE BEST CHANCE FOR ANY RAINFALL OF SIGNIFICANCE WILL OCCUR THROUGH
MON MORNING...THEN THE CHANCE OF ANY RAINFALL OF CONSEQUENCE WILL
DECREASE CONSIDERABLY BY MON EVENING.
THUS...THE OFFICIAL FORECAST CONTINUES WITH ISOLATED TO SCATTERED
SHOWERS INTO MON MORNING. THE BEST CHANCE OF HEAVIER RAINFALL WILL
OCCUR SOUTH-TO-SOUTHEAST OF TUCSON. ISOLATED TO PERHAPS SCATTERED
SHOWERS ARE EXPECTED MON AFTERNOON ACROSS SANTA CRUZ/COCHISE
COUNTIES. THERE APPEARS TO BE ENOUGH PROGGED INSTABILITY TO JUSTIFY
THE CONTINUATION OF A SLIGHT CHANCE OF THUNDERSTORMS MON AFTERNOON
MAINLY SE OF TUCSON. DRY CONDITIONS ARE FORECAST TO OCCUR ELSEWHERE
MON AFTERNOON.
A FEW LINGERING SHOWERS MAY OCCUR MON EVENING MAINLY ACROSS COCHISE
COUNTY. HAVE NOTED THAT THE 15/12Z ECMWF REMAINED CONSISTENT WITH
DEPICTING LIGHT QPF/S TO OCCUR MAINLY ACROSS THE WHITE MOUNTAINS MON
NIGHT. HOWEVER...THE 15/12Z NAM/GFS/CMC DEPICTED PRECIP-FREE
CONDITIONS TO OCCUR ACROSS THE AREA. ALTHOUGH THERE WILL BE AN
IMPULSE EMBEDDED WITHIN NWLY FLOW ALOFT THAT WILL MOVE SEWD ACROSS
ERN SECTIONS...THE ECMWF SOLUTION WAS DISCOUNTED GIVEN THE VERY DRY
REGIME UPSTREAM FROM THE AREA.
THEREAFTER...A HIGHLY AMPLIFIED PATTERN TUE WITH A STRONG HIGH
PRESSURE RIDGE ADJACENT THE WEST COAST AND DEEP TROUGH OVER THE ERN
CONUS IS PROGGED TO TRANSITION TOWARD A BROAD TROUGH OVER THE
ROCKIES AND CENTRAL CONUS BY NEXT WEEKEND. AT THIS TIME APPEARS THAT
ANY MEASURABLE PRECIP NEXT WEEKEND WILL BE NORTH AND EAST OF THIS
FORECAST AREA. HOWEVER...FORECAST CONFIDENCE IS SOMEWHAT LOW
REGARDING THIS SCENARIO...ESPECIALLY GIVEN THE RUN-TO-RUN
DIFFERENCES BETWEEN GFS/ECMWF SOLUTIONS. AT ANY RATE...HAVE OPTED
FOR PRECIP-FREE CONDITIONS DURING THE LATTER PART OF THE FORECAST
PERIOD.
HIGH TEMPS INTO NEXT WEEKEND WILL MOSTLY AVERAGE NEARLY 5-10 DEGS F
ABOVE NORMAL. THE WARMEST DAYS FOR MOST LOCALES WILL BE THUR-FRI.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
CURRENT DISCUSSION...MOLLERE
PREVIOUS DISCUSSION...FRANCIS
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
940 PM MST SUN FEB 15 2015
.UPDATE...
ISSUED AT 456 PM MST SUN FEB 15 2015
TRAVEL IMPACTS ALONG INTERSTATE 70 NEAR VAIL PASS CONTINUE LATE
THIS AFTERNOON AND SPOTTERS REPORTING MODERATE TO HEAVY SNOW STILL
FALLING AND SLOW TRAVEL. HAVE ADJUST POP GRIDS SLIGHTLY IN THIS
AREA TO FIT CURRENT TRENDS. EXPECT A LULL IN ACTIVITY AFTER 1900
THIS EVENING...WITH SNOW PICKING BACK UP AFTER 3 AM BASED ON
LATEST HRRR GUIDANCE.
&&
.SHORT TERM...(TONIGHT THROUGH MONDAY NIGHT)
ISSUED AT 300 PM MST SUN FEB 15 2015
A COLD FRONT MOVING SOUTHWARD AHEAD OF AN UPPER LEVEL SHORT WAVE
TROUGH WAS POSITIONED ALONG A KBCE-KAIB-KMTJ-KLXV LINE AT 2 PM
MST. WINDS HAD SHIFTED TO THE NORTHWEST AND INCREASED TO 15 TO 20
MPH WITH GUSTS TO 30 MPH AT A NUMBER OF LOCATIONS IN THE WAKE OF
THE FRONT. ALSO BEHIND THE FRONT...LIGHT PRECIPITATION HAD STARTED
WHICH WAS EXPECTED. KEEO REPORTED MIXED PHASE PRECIPITATION WHICH
BEGAN AS LIGHT RAIN AND CHANGED OVER TO SNOW. MEANWHILE...WEB CAMS
INDICATED LIGHT SNOW IN THE PARK RANGE ABOVE KSBS AS DID CAMS FROM
VAIL PASS AND THE VAIL SKI AREAS. SNOW WILL CONTINUE IN THE
NORTHERN AND CENTRAL MOUNTAINS DURING THE REMAINDER OF THE
AFTERNOON AS THE SHORTWAVE TROUGH MOVES OVERHEAD. ADDITIONAL LIFT
PROVIDED BY JET LEVEL DIVERGENCE AND OROGRAPHIC LIFT.
THOUGH THE SHORTWAVE TROUGH AXIS MOVES EAST OF THE DIVIDE THIS
EVENING...LATEST MODELS INDICATED THAT LIGHT TO MODERATE SNOWFALL
WILL CONTINUE OVER THE NORTHERN AND CENTRAL DIVIDE MOUNTAINS
THROUGH THE NIGHT DUE TO OROGRAPHIC LIFT IN AN ENVIRONMENT
FEATURING STEEP LAPSE RATES OF 7.5 TO 8.0 DEG/KM. SNOW INCREASES
IN COVERAGE AND INTENSITY ON MONDAY AS ANOTHER SHORTWAVE TROUGH
MOVES ACROSS THE AREA FROM THE NORTHWEST. THE LEFT EXIT REGION OF
A 135 KT JET MOVES OVERHEAD EARLY IN THE DAY TO ENHANCE LIFT. THE
BULK OF THE MOISTURE REMAINS OVER THE NORTHERN AND CENTRAL
COLORADO MOUNTAINS...THOUGH SOME SNOW WILL MOVE INTO THE WESTERN
SAN JUANS DURING THE AFTERNOON.
SINCE MODELS WERE MORE PERSISTENT WITH THE SNOWFALL THROUGH THE
NEXT 24 HOURS ACCUMULATIONS ARE EXPECTED TO REACH ADVISORY LEVELS
ACROSS THE ELKHEAD...PARK AND GORE RANGES AS WELL AS PORTIONS OF
THE ELK RANGE. NAM INDICATED AS MUCH AS 12 INCHES IN THE HIGHER
MOUNTAINS WHILE GFS AND ECMWF WERE A BIT MORE UNDERSTATED. GIVEN
GUIDANCE OUTPUT WENT AHEAD WITH STORM TOTALS OF 6 TO 12 INCHES IN
THESE AREAS.
SNOW DECREASES AND BECOMES MORE SCATTERED IN COVERAGE MONDAY NIGHT
AS THE SECOND WAVE SHIFTS EAST OF THE AREA. CLOUDS AND
PRECIPITATION WILL MODERATE TEMPERATURES TONIGHT WITH MOST
LOCATIONS ABOVE NORMAL. CONVERSELY...HIGHS WILL BE COOLER DUE TO
THE INFLUX OF COOLER AIR AND CLOUD COVER. DECREASING CLOUDS
MONDAY NIGHT WILL LEAD TO BELOW NORMAL LOWS BY TUESDAY MORNING.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 300 PM MST SUN FEB 15 2015
A NORTH-NORTHWEST FLOW WILL PREVAIL OVER THE FORECAST AREA ON
TUE...THEN WILL WEAKEN SOMEWHAT ON WEDNESDAY. A WEAK DISTURBANCE
EMBEDDED IN THE FLOW WILL DROP INTO THE NORTHERN PLAINS ON
TUE...ON THE BACKSIDE OF THE LARGE LOW PRESSURE TROUGH ACROSS THE
NATION`S MID SECTION TO THE EAST COAST. THIS WILL BRUSH OUR
NORTHEAST CORNER...AND ALONG WITH NORTHWEST OROGRAPHICS WILL KEEP
A CHANCE OF SNOW ALONG THE NORTHERN DIVIDE MOUNTAINS INTO THE
AFTERNOON. BY EARLY EVENING ANY LINGERING SHOWERS WILL END AS THE
GRADIENT BEGINS TO RELAX...AND MOISTURE DIMINISHES. THEN ON WED
ANOTHER EMBEDDED WAVE WILL PASS TO OUR NORTHEAST. THIS ONE WILL
HAVE LESS EFFECT ON OUR AREA AS IT WILL BE FARTHER AWAY AS HIGH
PRESSURE BUILDS OVER THE WEST COAST. THEREFORE DO NOT EXPECT MUCH
MORE THAN INCREASED CLOUDS FOR A TIME OVER MAINLY OVER THE
NORTHEAST CORNER.
HIGH PRESSURE WILL PERSIST OVER THE WEST COAST THROUGH THE END OF
THE LONG TERM PERIOD AND BEYOND. ON THU AND FRI...A MORE RELAXED
NORTHWEST FLOW OVER OUR AREA AND WARMING TEMPERATURES ALOFT WILL
ALLOW SURFACE TEMPERATURES TO REBOUND. THEN BY LATE FRIDAY THE FLOW
WILL BECOME WESTERLY AS A DEVELOPING SHORTWAVE TROUGH APPROACHES
FROM THE NORTH. THIS TROUGH WILL BRING OUR NEXT CHANCE WINTRY
CONDITIONS TO THE AREA THIS WEEKEND. HOWEVER THERE CONTINUES TO
BE SIGNIFICANT DIFFERENCES IN THE MODELS. SO CONFIDENCE IS NOT
HIGH. STAY TUNED TO FUTURE FORECASTS AS THIS STORM SYSTEM EVOLVES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 940 PM MST SUN FEB 15 2015
THE MAIN PIECE OF THIS STORM SYSTEM HAS PASSED EAST OF THE DIVIDE
THIS EVENING WITH A SHORT WINDOW OF IMPROVED VFR CONDITIONS AT ALL
OF THE TERMINAL SITES. HOWEVER A SECONDARY PIECE OF ENERGY WILL
BRING ANOTHER ROUND OF MOUNTAIN SNOW SHOWERS MAINLY AFTER 12Z
MONDAY. THIS PIECE OF THE STORM IS WEAKER BUT WITH COLD AIR IN
PLACE SNOW WILL BE EASIER TO PRODUCE. THEREFORE PERIODS OF MVFR TO
LOCAL IFR CONDITIONS WILL BE FORECAST FOR KASE AND KEGE. KRIL AND
KTEX WILL BE THE FRINGE OF THE LOWER CLOUDS AND WIDESPREAD SHOWERS
BUT LOWER FLIGHT CRITERIA COULD TEMPORARILY IMPACT THESE STATIONS
AS WELL AFTER 14Z TODAY. IMPROVING CONDITIONS AFTER SUNSET ON
MONDAY CAN BE EXPECTED.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...WINTER WEATHER ADVISORY UNTIL 6 PM MST MONDAY FOR COZ004-010.
UT...NONE.
&&
$$
UPDATE...JDC
SHORT TERM...NL
LONG TERM...EH
AVIATION...TGJT
Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
332 AM CST Mon Feb 16 2015
.SHORT TERM...(Today)
ISSUED AT 332 AM CST MON FEB 16 2015
Winter storm continues relatively on track with previous forecast.
Will not make any timing or coverage changes to the Winter Storm
headlines with the morning update. Counties can be cleared from the
headlines early if needed as the snowfall diminishes from NW to SE
this afternoon.
The 5" snowfall report from Edgewood at 150 am in SW Effingham
county lends confidence that the southeast 6 counties in the Winter
Storm Warning will reach into the 6 to 8" range before the end of
this event. Isolated spots may even climb above 8". Radar trends of
the bands of moderate snows are correlating closely to the RAP and
NAM depiction of 700mb Fn frontogenetic convergence. Projecting
forward through the day, our southeast counties will remain under
waves of Fn convergence and steady snows into the afternoon. Along
I-72, snows will be lighter, but the southern portions of the
advisory counties look on track to climb up to 3" before the
snowfall diminishes on the northern periphery. Have continued with
categorical PoPs in the winter storm warning and advisory areas this
morning, with slight chances up to Lincoln to Paris. PoPs were
trended downward each hour this afternoon to correlate with the
eastward translation of mid level forcing and deep moisture.
Additional accumulations today could reach between 2 to 4" in the
Warning counties S of I-70, with 1 to 2 inches for the southern
portions of the advisory counties between I-70 and I-72. Little to
no snowfall is expected north of a line from Rushville to Lincoln to
Champaign.
&&
.LONG TERM...(Tonight through Sunday)
ISSUED AT 332 AM CST MON FEB 16 2015
Have a 20-30% chance of light snow in far southeast IL early this
evening with little additional accumulations then. Best chance of
accumulationing snows this evening will be southeast of IL over KY
where as much as 10-16 inches of snow is expected. WNW winds will be
less than 10 mph tonight so limiting the amount of blowing and
drifting snow in southeast IL. Lows tonight of 8-13F with coldest
readings over deeper fresh snow cover in southeast IL. A cold front
to move se across central/se IL Tue morning and generally move
through dry with limited moisture. Have chance of flurries ne
counties overnight into Tue while better chances of light snow
further ne closer to MI/Lake MI. Highs Tue in lower 20s se of IL
river and upper teens nw of the IL river.
00Z forecast models continue to dig a strong upper level trof
southward into the Midwest including IL Tue night and Wed with
another surge of arctic air into the region. Scattered flurries with
mostly cloudy skies to accompany this trof along with bitter cold
temperatures. Lows Tue night around 5F. Highs Wed only in lower
teens eastern/se IL and 5-10F from I-55 west. Brisk nw winds Wed
with gusts 20-30 mph to give wind chills of 10-15 below zero
northern counties. Even colder Wed night with lows in the single
digits below zero and wind chills of 15-25 below zero. Wind chill
advisory may be needed wed night into thu morning even for central
and southeast IL. Strong upper level trof starts to shift east of IL
Thu but still very cold Thu with arctic high pressure moving into MS
river valley. Highs Thu of 8-13F and coldest from I-74 ne.
As high pressure drifts east of IL late this week and upper level
heights and 850 mb temps elevate, temps to moderate to mildest
readings on Sat in low to mid 30s for highs. But still below normal
for late Feb. Continued to stay close to guidance chances of light
snow this weekend starting Friday night. Big differences with
extended models this weekend with ECMWF showing strong low pressure
moving ne into IL Sat night while GFS keeps precipitation south of
central IL this weekend. GEM model through Sat is looking drier like
the GFS model. The Climate Prediction Center (CPC) 8-14 day
temperature outlook for Feb 23-Mar 1 has IL in greater than 70%
chance of below normal temperatures.
&&
.AVIATION...(For the 06Z TAFS through 06Z Monday night)
ISSUED AT 1100 PM CST SUN FEB 15 2015
VFR conditions are expected across the I-74 TAF sites while MVFR
cigs in snow can be expected at times at SPI and DEC into Monday
morning. Cigs will range from 1200-1500 feet in some of the steadier
snows, to 2500 to 3500 feet where there is a break in the precip.
The snow should begin to shift southeast of SPI and DEC between
12 and 15z Monday morning. Surface winds will continue to be a
non-factor through the period with a east to northeast wind the
remainder of tonight at 8 to 13 kts with winds backing more into
a northerly direction by afternoon.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY until 6 PM CST this evening FOR
ILZ049>052-061>063.
WINTER STORM WARNING until 6 PM CST this evening FOR ILZ066>068-
071>073.
&&
$$
SHORT TERM...Shimon
LONG TERM...07
AVIATION...Smith
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
329 AM EST MON FEB 16 2015
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 224 AM EST MON FEB 16 2015
A VIGOROUS LOW PRESSURE SYSTEM OVER THE SOUTHERN PLAINS IS EXPECTED
TO PUSH ACROSS THE DEEP SOUTH TODAY...SPREADING SNOW ACROSS THE
TENNESSEE AND OHIO VALLEYS...INCLUDING SOUTHERN PARTS OF CENTRAL
INDIANA. ACCUMULATING SNOW IS EXPECTED ACROSS SOUTHERN INDIANA. THE
LOW IS EXPECTED TO REACH THE CAROLINAS TONIGHT...BRINGING AN END TO
SNOWFALL ACROSS THE AREA TONIGHT.
ANOTHER ARCTIC HIGH PRESSURE SYSTEM IS THEN EXPECTED TO BUILD
ACROSS INDIANA IN THE WAKE OF THE LOW. THIS WILL RESULT IN ANOTHER
SHOT OF VERY COLD AIR TO SWEEP INTO INDIANA...PROVIDING DRY
CONDITIONS AND BELOW NORMAL TEMPERATURES. THROUGH THE MIDDLE OF THE
WEEK.
NEXT WEEKEND COULD SEE CHANCES FOR SNOW BUT ALSO A WARMUP AS THE
EAST COAST TROUGH FINALLY ABATES.
&&
.NEAR TERM /TODAY/...
ISSUED AT 224 AM EST MON FEB 16 2015
SURFACE ANALYSIS EARLY THIS MORNING SHOWS ARCTIC HIGH PRESSURE IN
PLACE OVER LOWER MICHIGAN AND A DEVELOPING SURFACE LOW ACROSS
EASTERN TEXAS. A VERY DRY AND COLD EASTERLY SURFACE FLOW WAS IN
PLACE ACROSS CENTRAL INDIANA...AS DEW POINTS WERE BELOW ZERO. THIS
INTRUSION OF DRY LOWER LEVEL AIR WILL BE IMPORTANT IN THIS
FORECAST. SATELLITE SHOWS A WAVE OF CLOUDS OVER MO...IL AND
INDIANA SPREADING EASTWARD. RADAR SHOWS A BAND OF SNOW ACROSS OUR
WARNING AREA IN SOUTHERN CENTRAL INDIANA WHERE SPOTTERS HAVE
REPORTED ABOUT 1/4 INCH OF ACCUMULATION AS OF 100 AM. NOTED ON
RADAR WAS A VERY SHARP CUT OFF SNOW VS NO-SNOW...AND DRY AIR WAS
PLAYING A NOTE. FOR EXAMPLE...DEWPOINTS AT BMG WERE -1. NO SNOW
THERE. DEW POINTS AT VINCENNES...14. SNOWING THERE. A 16 DEGREE
DIFFERENCE. THE VERY COLD TEMPERATURES IN PLACE WILL MAKE FOR
HIGHER SNOW/LIQUID RATIOS...RESULTING IN HIGH SNOW TOTALS IN THE
AREAS THAT GET SNOW.
GFS AND NAM ARE IN PRETTY GOOD AGREEMENT DURING THIS
PERIOD...PUSHING THE SURFACE LOW ACROSS MISSISSIPPI AND
ALABAMA...WHICH IS A MORE FAVORABLE TRACK FOR HEAVIEST SNOWS ACROSS
KENTUCKY. ALOFT A QUICK MOVING SHORT WAVE IS EXPECTED TO PUSH ACROSS
THE OHIO VALLEY THIS AFTERNOON AND EXIT THIS EVENING...EFFECTIVELY
ENDING LIFT THEN. ISENTROPIC SURFACE SHOW LITTLE IN THE WAY OF LIFT
ACROSS CENTRAL INDIANA...WITH BEST ISENTROPIC LIFT MUCH FARTHER
SOUTH. STILL NOTED IN THE 2-3 G/KG SPECIFIC HUMIDITY THAT IS
AVAILABLE ACROSS SOUTHERN PARTS OF CENTRAL INDIANA. Q VECTOR ALSO
SHOW BEST LIFT AND FORCING WELL SOUTH OF CENTRAL INDIANA...ACROSS
TENNESSEE AND KENTUCKY. MEANWHILE TIME HEIGHT SECTIONS SHOW GOOD
LIFT AND SATURATION THROUGH THE MORNING HOURS...WITH BEST MOISTURE
ACROSS THE SOUTHERN PARTS OF THE FORECAST AREA.
FORECAST SOUNDINGS ALSO HINT TOWARD DEEP SATURATION WITH BEST DEEP
MOISTURE IN PLACE ACROSS THE SOUTHERN PARTS OF THE FORECAST AREA
ALONG WITH PRECIPITATABLE WATER AMOUNTS NEAR 0.4 INCHES. ALSO
FAVORABLE FOR SNOW IN THE SOUNDINGS IS THE SATURATION IN THE
DENDRITIC GROWTH ZONE OF -10 TO -20. HRRR SUGGESTS BEST MOISTURE
WILL BE CONTAINED TO THE SOUTHERN PARTS OF THE FORECAST AREA.
FINALLY...NAM ALSO SUGGEST A WEAK TROWAL PUSHING ACROSS SOUTHERN
PARTS OF CENTRAL INDIANA THIS AFTERNOON.
THUS...WILL KEEP THE SNOW AMOUNTS IN PLACE ACROSS THE FAR SOUTHERN
COUNTIES...WITH NEAR 6 INCHES EXPECTED. WITH THE CONTINUE DRY
EASTERLY FLOW...LITTLE TO NO SNOW WILL BE EXPECTED ACROSS THE FAR
NORTHERN PARTS OF THE FORECAST AREA...WITH ONLY 1-2 INCHES OR LESS
ALONG THE I-70 CORRIDOR.
GIVEN ALL OF THIS ONGOING FORECAST HAS A GOOD HANDLE ON
THIS...HOWEVER WILL NOT HESITATE TO UPGRADE THE
SULLIVAN...BLOOMINGTON...AND GREENSBURG AREA TO A WARNING SHOULD
SNOW PILE UP QUICKER THAN EXPECTED. WILL USE 100 POPS SOUTH TO
NEAR 0 NORTH...WITH HIGHS COOLER THAN MAVMOS GIVEN THE COLD
NORTHEASTERLY FLOW.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
ISSUED AT 224 AM EST MON FEB 16 2015
GFS AND NAM ARE IN PRETTY GOOD AGREEMENT WITH THIS PERIOD AND WILL
USE A BLEND MAIN FORECAST CHALLENGE WILL BE TEMPS.
UPPER SHORT WAVE LOOKS TO DEPART THIS EVENING...AND FORCING ENDS
ACROSS THE AREA AS TIME HEIGHTS BEGIN TO SHOW SUBSIDENCE. FAR
ALOFT A FAVORABLE WAVE OF PV MOVES ACROSS CENTRAL
INDIANA...HOWEVER...ALL THE AVAILABLE MOISTURE WILL BE LONG GONE
TO THE EAST BEFORE THIS FEATURE ARRIVES. FORECAST SOUNDINGS
DRY OUT THROUGH THE NIGHT AS COLD AIR ADVECTION IS EXPECTED TO
RESUME IN THE MID LEVELS. BY 12Z TUES...850MB TEMPS FALL TO -13
AND THAT/S NOT ALL. THE COLD AIR ADVECTION WILL CONTINUE INTO
WEDNESDAY...WHEN 850MB TEMPS FALL TO -25C AND RAW NAM NUMERICAL
DATA SPITS OUT A 494 THICKNESS. ALOFT...BROAD CYCLONIC FLOW IS
EXPECTED TO REMAIN IN PLACE ACROSS THE EASTERN PARTS OF CANADA AND
THE UNITED STATES. THIS WILL ALLOW WHAT SEEMS LIKE AN ENDLESS FLOW
OF COLD AIR INTO THE OHIO VALLEY. WE WILL GET NO HELP AT THE
SURFACE AS SURFACE RIDGING LOOKS TO REMAIN WEST OF INDIANA UNTIL
AT LEAST THURSDAY AND BROAD CYCLONIC FLOW LOOKS TO PERSIST.
FURTHERMORE THE FLOW OFF OF LAKE MICHIGAN MAY RESULT IN SOME LAKE
CLOUDS/FLURRIES FROM TIME TO TIME ACROSS THE NORTHEAST PARTS OF
THE FORECAST AREA. THUS WILL TREND HIGHS COLDER THAN
MAVMOS...ESPECIALLY IN THE AREAS THAT RECEIVE NEW SNOW TODAY. WILL
ALSO TREND LOWS COLDER GIVEN THE STRONG COLD AIR ADVECTION.
SO IN SUMMARY...IT/S GONNA BE COLD...IT/S GONNA BE GRAY...AND IT/S
GONNA LAST UNTIL AT LEAST THURSDAY.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
ISSUED AT 243 AM EST MON FEB 16 2015
EXPECT CONTINUED COLD INTO THE LONG TERM PERIOD WITH A BIT OF A WARM
UP LATE IN THE PERIOD AS UPPER LEVEL FLOW BECOMES A BIT MORE ZONAL.
LOW CHANCES FOR PRECIP...MAINLY SNOW...APPEAR MERITED OVER THE
COMING WEEKEND...BUT IN LIGHT OF THE FAIRLY SIGNFICANT MODEL
DIFFERENCES IN HANDLING THIS PERIOD...SEE LITTLE REASON TO ADJUST
BLENDED INITIALIZATION...WHICH HAS THIS HANDLED RELATIVELY WELL.
&&
.AVIATION /DISCUSSION FOR THE 16/09Z TAF UPDATE/...
ISSUED AT 329 AM EST MON FEB 16 2015
MINOR ADJUSTMENTS REQUIRED AS SNOW MAKES ITS WAY NORTHWARD. CONTINUE
TO EXPECT WORST CONDITIONS AT BMG WITH BETTER CONDITIONS FURTHER
NORTH. PREVIOUS DISCUSSION FOLLOWS.
ISSUED AT 1131 PM EST SUN FEB 15 2015
LIGHT SNOW HAS BEEN DEVELOPING TO THE SOUTH OF THE TAF SITES OVER
THE PAST COUPLE OF HOURS. SHOULD START TO SEE SOME VISIBILITY
RESTRICTIONS IN THE KHUF/KBMG OVER THE NEXT FEW HOURS AS LEADING
EDGE OF SNOW AREA DRIFTS NORTH. SHORT TERM MODELS SUGGEST STRONGER
LIFT WILL BE REACHING KHUF/KBMG AROUND 160900Z...SO EXPECTING MORE
WIDESPREAD IFR/LIFR VISIBILITIES IN THOSE AREA AFTER THAT TIME.
THE KIND TERMINAL SHOULD START TO SEE VISIBILITY RESTRICTIONS IN
SNOW DEVELOPING AROUND 161200Z...WITH WIDESPREAD IFR RESTRICTIONS
SHORTLY AFTER THAT BASED ON TIMING OF BEST LIFT. FINER SCALE MODELS
ARE SUGGESTING HEAVIER SNOW/LIFR RESTRICTIONS MAY REACH KIND AS WELL
FOR A PERIOD AFTER SUNRISE MONDAY. CONFIDENCE IS LOWER HERE...SO
WILL KEEP LIFR RESTRICTIONS OUT OF KIND FOR NOW. THESE CONDITIONS
EXPECTED TO CONTINUE BEYOND 161800Z.
APPEARS THAT THE PRECIPITATION SHIELD WILL REMAIN SOUTH OF KLAF
TERMINAL.
SURFACE WINDS GENERALLY 080-110 DEGREES AT 8-11 KTS THROUGH MIDDAY
MONDAY.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL 7 PM EST THIS EVENING FOR INZ067>072.
WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR
INZ060>065.
&&
$$
SYNOPSIS...PUMA
NEAR TERM...PUMA
SHORT TERM...PUMA
LONG TERM...NIELD
AVIATION...JAS/NIELD
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSINDIANAPOLIS
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
243 AM EST MON FEB 16 2015
.UPDATE...
THE LONG TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 224 AM EST MON FEB 16 2015
A VIGOROUS LOW PRESSURE SYSTEM OVER THE SOUTHERN PLAINS IS EXPECTED
TO PUSH ACROSS THE DEEP SOUTH TODAY...SPREADING SNOW ACROSS THE
TENNESSEE AND OHIO VALLEYS...INCLUDING SOUTHERN PARTS OF CENTRAL
INDIANA. ACCUMULATING SNOW IS EXPECTED ACROSS SOUTHERN INDIANA. THE
LOW IS EXPECTED TO REACH THE CAROLINAS TONIGHT...BRINGING AN END TO
SNOWFALL ACROSS THE AREA TONIGHT.
ANOTHER ARCTIC HIGH PRESSURE SYSTEM IS THEN EXPECTED TO BUILD
ACROSS INDIANA IN THE WAKE OF THE LOW. THIS WILL RESULT IN ANOTHER
SHOT OF VERY COLD AIR TO SWEEP INTO INDIANA...PROVIDING DRY
CONDITIONS AND BELOW NORMAL TEMPERATURES. THROUGH THE MIDDLE OF THE
WEEK.
NEXT WEEKEND COULD SEE CHANCES FOR SNOW BUT ALSO A WARMUP AS THE
EAST COAST TROUGH FINALLY ABATES.
&&
.NEAR TERM /TODAY/...
ISSUED AT 224 AM EST MON FEB 16 2015
SURFACE ANALYSIS EARLY THIS MORNING SHOWS ARCTIC HIGH PRESSURE IN
PLACE OVER LOWER MICHIGAN AND A DEVELOPING SURFACE LOW ACROSS
EASTERN TEXAS. A VERY DRY AND COLD EASTERLY SURFACE FLOW WAS IN
PLACE ACROSS CENTRAL INDIANA...AS DEW POINTS WERE BELOW ZERO. THIS
INTRUSION OF DRY LOWER LEVEL AIR WILL BE IMPORTANT IN THIS
FORECAST. SATELLITE SHOWS A WAVE OF CLOUDS OVER MO...IL AND
INDIANA SPREADING EASTWARD. RADAR SHOWS A BAND OF SNOW ACROSS OUR
WARNING AREA IN SOUTHERN CENTRAL INDIANA WHERE SPOTTERS HAVE
REPORTED ABOUT 1/4 INCH OF ACCUMULATION AS OF 100 AM. NOTED ON
RADAR WAS A VERY SHARP CUT OFF SNOW VS NO-SNOW...AND DRY AIR WAS
PLAYING A NOTE. FOR EXAMPLE...DEWPOINTS AT BMG WERE -1. NO SNOW
THERE. DEW POINTS AT VINCENNES...14. SNOWING THERE. A 16 DEGREE
DIFFERENCE. THE VERY COLD TEMPERATURES IN PLACE WILL MAKE FOR
HIGHER SNOW/LIQUID RATIOS...RESULTING IN HIGH SNOW TOTALS IN THE
AREAS THAT GET SNOW.
GFS AND NAM ARE IN PRETTY GOOD AGREEMENT DURING THIS
PERIOD...PUSHING THE SURFACE LOW ACROSS MISSISSIPPI AND
ALABAMA...WHICH IS A MORE FAVORABLE TRACK FOR HEAVIEST SNOWS ACROSS
KENTUCKY. ALOFT A QUICK MOVING SHORT WAVE IS EXPECTED TO PUSH ACROSS
THE OHIO VALLEY THIS AFTERNOON AND EXIT THIS EVENING...EFFECTIVELY
ENDING LIFT THEN. ISENTROPIC SURFACE SHOW LITTLE IN THE WAY OF LIFT
ACROSS CENTRAL INDIANA...WITH BEST ISENTROPIC LIFT MUCH FARTHER
SOUTH. STILL NOTED IN THE 2-3 G/KG SPECIFIC HUMIDITY THAT IS
AVAILABLE ACROSS SOUTHERN PARTS OF CENTRAL INDIANA. Q VECTOR ALSO
SHOW BEST LIFT AND FORCING WELL SOUTH OF CENTRAL INDIANA...ACROSS
TENNESSEE AND KENTUCKY. MEANWHILE TIME HEIGHT SECTIONS SHOW GOOD
LIFT AND SATURATION THROUGH THE MORNING HOURS...WITH BEST MOISTURE
ACROSS THE SOUTHERN PARTS OF THE FORECAST AREA.
FORECAST SOUNDINGS ALSO HINT TOWARD DEEP SATURATION WITH BEST DEEP
MOISTURE IN PLACE ACROSS THE SOUTHERN PARTS OF THE FORECAST AREA
ALONG WITH PRECIPITATABLE WATER AMOUNTS NEAR 0.4 INCHES. ALSO
FAVORABLE FOR SNOW IN THE SOUNDINGS IS THE SATURATION IN THE
DENDRITIC GROWTH ZONE OF -10 TO -20. HRRR SUGGESTS BEST MOISTURE
WILL BE CONTAINED TO THE SOUTHERN PARTS OF THE FORECAST AREA.
FINALLY...NAM ALSO SUGGEST A WEAK TROWAL PUSHING ACROSS SOUTHERN
PARTS OF CENTRAL INDIANA THIS AFTERNOON.
THUS...WILL KEEP THE SNOW AMOUNTS IN PLACE ACROSS THE FAR SOUTHERN
COUNTIES...WITH NEAR 6 INCHES EXPECTED. WITH THE CONTINUE DRY
EASTERLY FLOW...LITTLE TO NO SNOW WILL BE EXPECTED ACROSS THE FAR
NORTHERN PARTS OF THE FORECAST AREA...WITH ONLY 1-2 INCHES OR LESS
ALONG THE I-70 CORRIDOR.
GIVEN ALL OF THIS ONGOING FORECAST HAS A GOOD HANDLE ON
THIS...HOWEVER WILL NOT HESITATE TO UPGRADE THE
SULLIVAN...BLOOMINGTON...AND GREENSBURG AREA TO A WARNING SHOULD
SNOW PILE UP QUICKER THAN EXPECTED. WILL USE 100 POPS SOUTH TO
NEAR 0 NORTH...WITH HIGHS COOLER THAN MAVMOS GIVEN THE COLD
NORTHEASTERLY FLOW.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
ISSUED AT 224 AM EST MON FEB 16 2015
GFS AND NAM ARE IN PRETTY GOOD AGREEMENT WITH THIS PERIOD AND WILL
USE A BLEND MAIN FORECAST CHALLENGE WILL BE TEMPS.
UPPER SHORT WAVE LOOKS TO DEPART THIS EVENING...AND FORCING ENDS
ACROSS THE AREA AS TIME HEIGHTS BEGIN TO SHOW SUBSIDENCE. FAR
ALOFT A FAVORABLE WAVE OF PV MOVES ACROSS CENTRAL
INDIANA...HOWEVER...ALL THE AVAILABLE MOISTURE WILL BE LONG GONE
TO THE EAST BEFORE THIS FEATURE ARRIVES. FORECAST SOUNDINGS
DRY OUT THROUGH THE NIGHT AS COLD AIR ADVECTION IS EXPECTED TO
RESUME IN THE MID LEVELS. BY 12Z TUES...850MB TEMPS FALL TO -13
AND THAT/S NOT ALL. THE COLD AIR ADVECTION WILL CONTINUE INTO
WEDNESDAY...WHEN 850MB TEMPS FALL TO -25C AND RAW NAM NUMERICAL
DATA SPITS OUT A 494 THICKNESS. ALOFT...BROAD CYCLONIC FLOW IS
EXPECTED TO REMAIN IN PLACE ACROSS THE EASTERN PARTS OF CANADA AND
THE UNITED STATES. THIS WILL ALLOW WHAT SEEMS LIKE AN ENDLESS FLOW
OF COLD AIR INTO THE OHIO VALLEY. WE WILL GET NO HELP AT THE
SURFACE AS SURFACE RIDGING LOOKS TO REMAIN WEST OF INDIANA UNTIL
AT LEAST THURSDAY AND BROAD CYCLONIC FLOW LOOKS TO PERSIST.
FURTHERMORE THE FLOW OFF OF LAKE MICHIGAN MAY RESULT IN SOME LAKE
CLOUDS/FLURRIES FROM TIME TO TIME ACROSS THE NORTHEAST PARTS OF
THE FORECAST AREA. THUS WILL TREND HIGHS COLDER THAN
MAVMOS...ESPECIALLY IN THE AREAS THAT RECEIVE NEW SNOW TODAY. WILL
ALSO TREND LOWS COLDER GIVEN THE STRONG COLD AIR ADVECTION.
SO IN SUMMARY...IT/S GONNA BE COLD...IT/S GONNA BE GRAY...AND IT/S
GONNA LAST UNTIL AT LEAST THURSDAY.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
ISSUED AT 243 AM EST MON FEB 16 2015
EXPECT CONTINUED COLD INTO THE LONG TERM PERIOD WITH A BIT OF A WARM
UP LATE IN THE PERIOD AS UPPER LEVEL FLOW BECOMES A BIT MORE ZONAL.
LOW CHANCES FOR PRECIP...MAINLY SNOW...APPEAR MERITED OVER THE
COMING WEEKEND...BUT IN LIGHT OF THE FAIRLY SIGNFICANT MODEL
DIFFERENCES IN HANDLING THIS PERIOD...SEE LITTLE REASON TO ADJUST
BLENDED INITIALIZATION...WHICH HAS THIS HANDLED RELATIVELY WELL.
&&
.AVIATION /DISCUSSION FOR THE 160600Z TAFS/...
ISSUED AT 1131 PM EST SUN FEB 15 2015
LIGHT SNOW HAS BEEN DEVELOPING TO THE SOUTH OF THE TAF SITES OVER
THE PAST COUPLE OF HOURS. SHOULD START TO SEE SOME VISIBILITY
RESTRICTIONS IN THE KHUF/KBMG OVER THE NEXT FEW HOURS AS LEADING
EDGE OF SNOW AREA DRIFTS NORTH. SHORT TERM MODELS SUGGEST STRONGER
LIFT WILL BE REACHING KHUF/KBMG AROUND 160900Z...SO EXPECTING MORE
WIDESPREAD IFR/LIFR VISIBILITIES IN THOSE AREA AFTER THAT TIME.
THE KIND TERMINAL SHOULD START TO SEE VISIBILITY RESTRICTIONS IN
SNOW DEVELOPING AROUND 161200Z...WITH WIDESPREAD IFR RESTRICTIONS
SHORTLY AFTER THAT BASED ON TIMING OF BEST LIFT. FINER SCALE MODELS
ARE SUGGESTING HEAVIER SNOW/LIFR RESTRICTIONS MAY REACH KIND AS WELL
FOR A PERIOD AFTER SUNRISE MONDAY. CONFIDENCE IS LOWER HERE...SO
WILL KEEP LIFR RESTRICTIONS OUT OF KIND FOR NOW. THESE CONDITIONS
EXPECTED TO CONTINUE BEYOND 161800Z.
APPEARS THAT THE PRECIPITATION SHIELD WILL REMAIN SOUTH OF KLAF
TERMINAL.
SURFACE WINDS GENERALLY 080-110 DEGREES AT 8-11 KTS THROUGH MIDDAY
MONDAY.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL 7 PM EST THIS EVENING FOR INZ067>072.
WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR
INZ060>065.
&&
$$
SYNOPSIS...PUMA
NEAR TERM...PUMA
SHORT TERM...PUMA
LONG TERM...NIELD
AVIATION...JAS
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSINDIANAPOLIS
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
224 AM EST MON FEB 16 2015
.UPDATE...
THE SYNOPSIS...NEAR TERM AND SHORT TERM SECTIONS HAVE BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 224 AM EST MON FEB 16 2015
A VIGOROUS LOW PRESSURE SYSTEM OVER THE SOUTHERN PLAINS IS
EXPECTED TO PUSH ACROSS THE DEEP SOUTH TODAY...SPREAD SNOW ACROSS
THE TENNESSEE AND OHIO VALLEYS...INCLUDING SOUTHERN PARTS OF
CENTRAL INDIANA. ACCUMULATING SNOW IS EXPECTED ACROSS SOUTHERN
INDIANA. THE LOW IS EXPECTED TO REACH THE CAROLINAS
TONIGHT...BRINGING AN END TO SNOWFALL ACROSS THE AREA TONIGHT.
ANOTHER ARCTIC HIGH PRESSURE SYSTEM IS THEN EXPECTED TO BUILD
ACROSS INDIANA IN THE WAKE OF THE LOW. THIS WILL RESULT IN ANOTHER
SHOT OF VERY COLD AIR TO SWEEP INTO THE INDIANA...PROVIDING DRY
CONDITIONS AND BELOW NORMAL TEMPERATURES. THROUGH THE MIDDLE OF
THE WEEK.
NEXT WEEKEND COULD SEE CHANCES FOR SNOW BUT ALSO A WARMUP AS THE
EAST COAST TROUGH FINALLY ABATES.
&&
.NEAR TERM /TODAY/...
ISSUED AT 224 AM EST MON FEB 16 2015
SURFACE ANALYSIS EARLY THIS MORNING SHOWS ARCTIC HIGH PRESSURE IN
PLACE OVER LOWER MICHIGAN AND A DEVELOPING SURFACE LOW ACROSS
EASTERN TEXAS. A VERY DRY AND COLD EASTERLY SURFACE FLOW WAS IN
PLACE ACROSS CENTRAL INDIANA...AS DEW POINTS WERE BELOW ZERO. THIS
INTRUSION OF DRY LOWER LEVEL AIR WILL BE IMPORTANT IN THIS
FORECAST. SATELLITE SHOWS A WAVE OF CLOUDS OVER MO...IL AND
INDIANA SPREADING EASTWARD. RADAR SHOWS A BAND OF SNOW ACROSS OUR
WARNING AREA IN SOUTHERN CENTRAL INDIANA WHERE SPOTTERS HAVE
REPORTED ABOUT 1/4 INCH OF ACCUMULATION AS OF 100 AM. NOTED ON
RADAR WAS A VERY SHARP CUT OFF SNOW VS NO-SNOW...AND DRY AIR WAS
PLAYING A NOTE. FOR EXAMPLE...DEWPOINTS AT BMG WERE -1. NO SNOW
THERE. DEW POINTS AT VINCENNES...14. SNOWING THERE. A 16 DEGREE
DIFFERENCE. THE VERY COLD TEMPERATURES IN PLACE WILL MAKE FOR
HIGHER SNOW/LIQUID RATIOS...RESULTING IN HIGH SNOW TOTALS IN THE
AREAS THAT GET SNOW.
GFS AND NAM ARE IN PRETTY GOOD AGREEMENT DURING THIS
PERIOD...PUSHING THE SURFACE LOW ACROSS MISSISSIPPI AND
ALABAMA...WHICH IS A MORE FAVORABLE TRACK FOR HEAVIES SNOWS ACROSS
KENTUCKY. ALOFT A QUICK MOVING SHORT WAVE IS EXPECTED TO PUSH
ACROSS THE OHIO VALLEY THIS AFTERNOON AND EXIT THIS
EVENING...EFFECTIVELY ENDING LIFT THEN. ISENTROPIC SURFACE SHOW
LITTLE IN THE WAY OF LIFT ACROSS CENTRAL INDIANA...WITH BEST
ISENTROPIC LIFT MUCH FARTHER SOUTH. STILL NOTED IN THE 2-3 G/KG
SPECIFIC HUMIDITY THAT IS AVAILABLE ACROSS SOUTHERN PARTS OF
CENTRAL INDIANA. Q VECTOR ALSO SHOW BEST LIFT AND FORCING WELL
SOUTH OF CENTRAL INDIANA...ACROSS TENNESSEE AND KENTUCKY.
MEANWHILE TIME HEIGHT SECTIONS SHOW GOOD LIFT AND SATURATION
THROUGH THE MORNING HOURS...WITH BEST MOISTURE ACROSS THE SOUTHERN
PARTS OF THE FORECAST AREA.
FORECAST SOUNDINGS ALSO HINT TOWARD DEEP SATURATION WITH BEST DEEP
MOISTURE IN PLACE ACROSS THE SOUTHERN PARTS OF THE FORECAST AREA
ALONG WITH PRECIPITATABLE WATER AMOUNTS NEAR 0.4 INCHES. ALSO
FAVORABLE FOR SNOW IN THE SOUNDINGS IS THE SATURATION IN THE
DENDRITIC GROWTH ZONE OF -10 TO -20. HRRR SUGGESTS BEST MOISTURE
WILL BE CONTAINED TO THE SOUTHERN PARTS OF THE FORECAST AREA.
FINALLY...NAM ALSO SUGGEST A WEAK TROWAL PUSHING ACROSS SOUTHERN
PARTS OF CENTRAL INDIANA THIS AFTERNOON.
THUS...WILL KEEP THE SNOW AMOUNTS IN PLACE ACROSS THE FAR SOUTHERN
COUNTIES...WITH NEAR 6 INCHES EXPECTED. WITH THE CONTINUE DRY
EASTERLY FLOW...LITTLE TO NO SNOW WILL BE EXPECTED ACROSS THE FAR
NORTHERN PARTS OF THE FORECAST AREA...WITH ONLY 1-2 INCHES OR LESS
ALONG THE I-70 CORRIDOR.
GIVEN ALL OF THIS ONGOING FORECAST HAS A GOOD HANDLE ON
THIS...HOWEVER WILL NOT HESITATE TO UPGRADE THE
SULLIVAN...BLOOMINGTON...AND GREENSBURG AREA TO A WARNING SHOULD
SNOW PILE UP QUICKER THAN EXPECTED. WILL USE 100 POPS SOUTH TO
NEAR 0 NORTH...WITH HIGHS COOLER THAN MAVMOS GIVEN THE COLD
NORTHEASTERLY FLOW.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
ISSUED AT 224 AM EST MON FEB 16 2015
GFS AND NAM ARE IN PRETTY GOOD AGREEMENT WITH THIS PERIOD AND WILL
USE A BLEND MAIN FORECAST CHALLENGE WILL BE TEMPS.
UPPER SHORT WAVE LOOKS TO DEPART THIS EVENING...AND FORCING ENDS
ACROSS THE AREA AS TIME HEIGHTS BEGIN TO SHOW SUBSIDENCE. FAR
ALOFT A FAVORABLE WAVE OF PV MOVES ACROSS CENTRAL
INDIANA...HOWEVER...ALL THE AVAILABLE MOISTURE WILL BE LONG GONE
TO THE EAST BEFORE THIS FEATURE ARRIVES. FORECAST SOUNDINGS
DRY OUT THROUGH THE NIGHT AS COLD AIR ADVECTION IS EXPECTED TO
RESUME IN THE MID LEVELS. BY 12Z TUES...850MB TEMPS FALL TO -13
AND THAT/S NOT ALL. THE COLD AIR ADVECTION WILL CONTINUE INTO
WEDNESDAY...WHEN 850MB TEMPS FALL TO -25C AND RAW NAM NUMERICAL
DATA SPITS OUT A 494 THICKNESS. ALOFT...BROAD CYCLONIC FLOW IS
EXPECTED TO REMAIN IN PLACE ACROSS THE EASTERN PARTS OF CANADA AND
THE UNITED STATES. THIS WILL ALLOW WHAT SEEMS LIKE AN ENDLESS FLOW
OF COLD AIR INTO THE OHIO VALLEY. WE WILL GET NO HELP AT THE
SURFACE AS SURFACE RIDGING LOOKS TO REMAIN WEST OF INDIANA UNTIL
AT LEAST THURSDAY AND BROAD CYCLONIC FLOW LOOKS TO PERSIST.
FURTHERMORE THE FLOW OFF OF LAKE MICHIGAN MAY RESULT IN SOME LAKE
CLOUDS/FLURRIES FROM TIME TO TIME ACROSS THE NORTHEAST PARTS OF
THE FORECAST AREA. THUS WILL TREND HIGHS COLDER THAN
MAVMOS...ESPECIALLY IN THE AREAS THAT RECEIVE NEW SNOW TODAY. WILL
ALSO TREND LOWS COLDER GIVEN THE STRONG COLD AIR ADVECTION.
SO IN SUMMARY...IT/S GONNA BE COLD...IT/S GONNA BE GRAY...AND IT/S
GONNA LAST UNTIL AT LEAST THURSDAY.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
ISSUED AT 155 PM EST SUN FEB 15 2015
MAIN FOCUS FOR THE EXTENDED WILL BE ON TIMING OF POPS AS WELL AS
TEMPERATURES.
MODELS ARE HAVING TIMING DIFFERENCES WITH WEAK SURFACE SYSTEM THAT
IS EXPECTED TO IMPACT CENTRAL INDIANA NEXT WEEKEND WITH THE 12Z GEM
BEING THE FASTEST...00Z ECMWF THE MIDDLE GROUND AND 12Z GFS THE
FASTEST. THESE DIFFERENCES RESULT FROM FAST NORTHWEST FLOW ALOFT
OVER THE AREA IN BETWEEN THE PERSISTENT WESTERN RIDGE AND
NORTHEASTERN TROUGH. WITH THESE KIND OF DIFFERENCES...PREFER TO PLAY
IT SAFE AND NOT ROCK THE BOAT AND KEEP CHANCE POPS FROM FRIDAY NIGHT
THROUGH SUNDAY. 00Z ECMWF THERMAL PROFILE PROGS SUGGEST SOME RAIN
COULD MIX IN WITH THE SNOW...ESPECIALLY ACROSS OUR SOUTHERN
COUNTIES...HOWEVER THE COLDER 12Z GFS KEEPS IT ALL SNOW. WITH DECENT
SOUTHERLY FLOW ON THE BACK OF THE DEPARTING ARCTIC HIGH...COULD SEE
A MIX. HOWEVER...WILL KEEP IT ALL SNOW FOR NOW UNTIL OR IF THE
EXTENDED MODELS CONTINUE TO TREND WARMER.
LOW LEVEL THERMAL PROGS SUGGEST LATE WEEKEND WARMUP IN THE WAKE OF
THE ARCTIC HIGH. REGIONAL BLEND APPEARS TO BE HANDLING THIS WEEK
WITH TEMPERATURES GETTING CLOSER TO NORMAL BY SATURDAY.
&&
.AVIATION /DISCUSSION FOR THE 160600Z TAFS/...
ISSUED AT 1131 PM EST SUN FEB 15 2015
LIGHT SNOW HAS BEEN DEVELOPING TO THE SOUTH OF THE TAF SITES OVER
THE PAST COUPLE OF HOURS. SHOULD START TO SEE SOME VISIBILITY
RESTRICTIONS IN THE KHUF/KBMG OVER THE NEXT FEW HOURS AS LEADING
EDGE OF SNOW AREA DRIFTS NORTH. SHORT TERM MODELS SUGGEST STRONGER
LIFT WILL BE REACHING KHUF/KBMG AROUND 160900Z...SO EXPECTING MORE
WIDESPREAD IFR/LIFR VISIBILITIES IN THOSE AREA AFTER THAT TIME.
THE KIND TERMINAL SHOULD START TO SEE VISIBILITY RESTRICTIONS IN
SNOW DEVELOPING AROUND 161200Z...WITH WIDESPREAD IFR RESTRICTIONS
SHORTLY AFTER THAT BASED ON TIMING OF BEST LIFT. FINER SCALE MODELS
ARE SUGGESTING HEAVIER SNOW/LIFR RESTRICTIONS MAY REACH KIND AS WELL
FOR A PERIOD AFTER SUNRISE MONDAY. CONFIDENCE IS LOWER HERE...SO
WILL KEEP LIFR RESTRICTIONS OUT OF KIND FOR NOW. THESE CONDITIONS
EXPECTED TO CONTINUE BEYOND 161800Z.
APPEARS THAT THE PRECIPITATION SHIELD WILL REMAIN SOUTH OF KLAF
TERMINAL.
SURFACE WINDS GENERALLY 080-110 DEGREES AT 8-11 KTS THROUGH MIDDAY
MONDAY.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL 7 PM EST THIS EVENING FOR INZ067>072.
WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR
INZ060>065.
&&
$$
SYNOPSIS...PUMA
NEAR TERM...PUMA
SHORT TERM...PUMA
LONG TERM...MK
AVIATION...JAS
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
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AREA FORECAST DISCUSSION
NWS DODGE CITY KS
333 AM CST MON FEB 16 2015
...UPDATE TO LONG TERM...
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 207 AM CST MON FEB 16 2015
A BAND OF STEADIER SNOWFALL EARLIER THIS MORNING RELATED WELL
WITH A 700MB BAROCLINIC ZONE THAT WAS LOCATED AHEAD OF AN UPPER
LEVEL TROUGH WHICH WAS CROSSING EASTERN COLORADO AS OF 06Z. NAM,
HRRR, AND RAP WERE ALL IN DECENT AGREEMENT WITH THIS BAND OF
STEADIER SNOWFALL CROSSING ALL OF SOUTHWEST AND MOST OF SOUTH
CENTRAL KANSAS BY 12Z MONDAY. SOME LIGHTER SNOWFALL IS STILL
EXPECTED EARLY THIS MORNING SOUTH AND EAST OF A DODGE CITY,
HOWEVER EVEN THIS LIGHT PRECIPITATION IS EXPECTED TO BE ENDING BY
15Z. ADDITIONAL SNOWFALL AMOUNTS EARLY THIS MORNING IN THIS AREA
OF LINGERING SNOWFALL IS EXPECTED TO BE LESS THAN ONE HALF OF AN
INCH. LARGE SCALE SUBSIDENCE IS FORECAST BEHIND THIS UPPER LEVEL
TROUGH AS IT MOVES EAST OF THE AREA EARLY THIS MORNING, HOWEVER
BUFR SOUNDINGS AND EVEN THE HRRR HINT AT SOME LINGERING LOW LEVEL
MOISTURE/STATUS DURING EARLY MORNING HOURS. SOME HIGH LEVEL
MOISTURE/CLOUDS WILL THEN BE POSSIBLE DURING THE AFTERNOON.
CONFIDENCE IS NOT HIGH ON HOW MUCH AFTERNOON CLOUD COVER THERE
WILL BE LATER THIS AFTERNOON, HOWEVER GIVEN THE CURRENT CLOUD
COVER EXPECTED TODAY ALONG WITH THE SNOW THAT FELL DURING THE
OVERNIGHT HOURS WILL UNDERCUT THE COOLER MET GUIDANCE BY SEVERAL
DEGREES. THIS WILL BE CLOSE TO THE PREVIOUS FORECAST FOR HIGHS
TODAY WHICH WILL RANGE FROM THE MID 30S TO NEAR 40.
TONIGHT...CLOUDS WILL BE ON THE INCREASE AS ANOTHER UPPER LEVEL
DISTURBANCE BEGINS TO APPROACH CENTRAL HIGH PLAINS FROM THE
NORTHWEST. A SURFACE BOUNDARY WILL MOVE SOUTH/SOUTHWEST ACROSS
NORTH CENTRAL KANSAS OVERNIGHT WITH SOME INCREASING MOISTURE AND
LIFT DEVELOPING NORTH OF THIS BOUNDARY. THIS MAY GIVE RISE TO A
FEW FLURRIES TOWARDS DAYBREAK. AT THIS TIME GIVEN WHERE THIS
SURFACE BOUNDARY IS EXPECTED TO BE LOCATED TOWARDS 12Z TUESDAY
WILL KEEP A MENTION THE SLIGHT CHANCE FOR LIGHT SNOW GOING ACROSS
MAINLY NORTH CENTRAL KANSAS. WITH THE INCREASING CLOUDS TONIGHT
HAVE DECIDED TO STAY CLOSE TO THE LATEST GUIDANCE WITH
TEMPERATURES FALLING BACK TO AROUND 20 DEGREES.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 333 AM CST MON FEB 16 2015
TUESDAY:
INCREASES POPS NEAR HAYS TUESDAY EVENING AS AN 850-700-HPA WEAK PERTURBATION/BAROCLINIC
ZONE MOVES ACROSS AND COULD PROVIDE THE REGION WITH A SHOWERS/SNOW SHOWERS.
STEEPENING LOW LEVEL LAPSE RATES AND OUTPUT FROM THE ARW CORES AND THE
4 KM NAM GIVE SOME CREDENCE TO THIS. ACTIVITY SHOULD BE FAIRLY LIGHT
IN THE DRY NORTHWESTERLY FLOW ALOFT. TEMPERATURES WILL WARM TO AROUND
40-45F OUTSIDE THIS ACTIVITY ACROSS THE CENTRAL AND SOUTHERN ZONES WITH
COOLER 30S NEAR THE I70 CORRIDOR. OVERNIGHT LOWS WILL BE COLD AND IN
THE UPPER TEENS.
WEDNESDAY:
FAIRLY STRONG NNW FLOW ALOFT WILL CONTINUE ALONG WITH HIGH PRESSURE
ACROSS THE CENTRAL AND NORTHERN PLAINS. THERE WILL BE SOME WEAK LEE
TROUGHING BY WEDNESDAY EVENING AND TEMPERATURES SHOULD MODERATE A FEW
DEGREES - PARTICULARLY ACROSS THE SOUTHWEST ZONES TO MAINLY THE 40S.
NO PRECIPITATION IS EXPECTED.
AND THE REST:
ATTENTION THEN TURNS TO THE WEEKEND. SUPERBLEND STILL HAS CHANCE POPS,
WHICH LOOKS REASONABLE NOW AS THE NEXT WAVE MOVES ACROSS THE CENTRAL
PLAINS. BOTH GFS AND ECMWF SHOW THE CHANCE FOR ACCUMULATING SNOWFALL
WITH THIS NEXT SYSTEM. RIGHT NOW IT IS WAY TOO EARLY TO TELL WHERE AND
HOW MUCH SNOWFALL IS POSSIBLE. ONE THING THAT IS MORE CERTAIN IS MUCH
COOLER TEMPERATURES FOLLOWING A WARM UP. COORDINATED WITH GLD AND TWEAKED
TEMPERATURES SOMEWHAT TO AT LEAST TREND COOLER. TEMPS NOW ARE PROBABLY
WAY TOO WARM AND WILL NEED TO BE ADJUSTED IF THE MODELS CONTINUE AS
ROBUST WITH THIS UPCOMING COLD OUTBREAK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1105 PM CST SUN FEB 15 2015
IFR CEILINGS AND LIFR VISIBILITIES CAN BE EXPECTED WITH A BAND OF
STEADY SNOW WHICH WILL BE CROSSING SOUTHWEST KANSAS THROUGH 12Z
MONDAY. THIS IS BASED ON 04Z SURFACE OBSERVATIONS CURRENTLY IN
THE BAND OF STEADIER SNOWFALL ALONG WITH THE AGREEMENT BETWEEN THE
00Z NAM BUFR SOUNDINGS AND LATEST HRRR. THE NAM AND HRRR ALSO
INDICATED THAT THE BETTER CHANCES FOR THESE LOW IFR/LIFR
CONDITIONS WILL OCCUR AT HYS THROUGH 07Z, GCK BETWEEN 06 AND 08Z,
AND THEN DDC BETWEEN 08Z AND 11Z. OUTSIDE THIS AREA OF STEADY
SNOWFALL MVFR CONDITIONS CAN BE EXPECTED THROUGH LATE MORNING.
AFTER 18Z MONDAY THESE LOW CLOUD ARE FORECAST TO GIVE WAY TO VFR
CONDITIONS AS AN UPPER LEVEL TROUGH THAT WILL BE CROSSES WESTERN
KANSAS. WINDS ACROSS WESTERN KANSAS WILL BE NORTH NORTHWEST AT 10
KNOTS OR LESS.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 38 22 41 19 / 20 10 10 0
GCK 38 21 41 18 / 10 10 10 0
EHA 38 23 42 22 / 30 10 10 0
LBL 38 21 43 20 / 20 10 10 0
HYS 39 22 35 17 / 10 20 30 10
P28 37 23 41 19 / 40 10 20 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BURGERT
LONG TERM...SUGDEN
AVIATION...BURGERT
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
211 AM CST MON FEB 16 2015
...UPDATED SHORT TERM DISCUSSION...
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 207 AM CST MON FEB 16 2015
A BAND OF STEADIER SNOWFALL EARLIER THIS MORNING RELATED WELL
WITH A 700MB BAROCLINIC ZONE THAT WAS LOCATED AHEAD OF AN UPPER
LEVEL TROUGH WHICH WAS CROSSING EASTERN COLORADO AS OF 06Z. NAM,
HRRR, AND RAP WERE ALL IN DECENT AGREEMENT WITH THIS BAND OF
STEADIER SNOWFALL CROSSING ALL OF SOUTHWEST AND MOST OF SOUTH
CENTRAL KANSAS BY 12Z MONDAY. SOME LIGHTER SNOWFALL IS STILL
EXPECTED EARLY THIS MORNING SOUTH AND EAST OF A DODGE CITY,
HOWEVER EVEN THIS LIGHT PRECIPITATION IS EXPECTED TO BE ENDING BY
15Z. ADDITIONAL SNOWFALL AMOUNTS EARLY THIS MORNING IN THIS AREA
OF LINGERING SNOWFALL IS EXPECTED TO BE LESS THAN ONE HALF OF AN
INCH. LARGE SCALE SUBSIDENCE IS FORECAST BEHIND THIS UPPER LEVEL
TROUGH AS IT MOVES EAST OF THE AREA EARLY THIS MORNING, HOWEVER
BUFR SOUNDINGS AND EVEN THE HRRR HINT AT SOME LINGERING LOW LEVEL
MOISTURE/STATUS DURING EARLY MORNING HOURS. SOME HIGH LEVEL
MOISTURE/CLOUDS WILL THEN BE POSSIBLE DURING THE AFTERNOON.
CONFIDENCE IS NOT HIGH ON HOW MUCH AFTERNOON CLOUD COVER THERE
WILL BE LATER THIS AFTERNOON, HOWEVER GIVEN THE CURRENT CLOUD
COVER EXPECTED TODAY ALONG WITH THE SNOW THAT FELL DURING THE
OVERNIGHT HOURS WILL UNDERCUT THE COOLER MET GUIDANCE BY SEVERAL
DEGREES. THIS WILL BE CLOSE TO THE PREVIOUS FORECAST FOR HIGHS
TODAY WHICH WILL RANGE FROM THE MID 30S TO NEAR 40.
TONIGHT...CLOUDS WILL BE ON THE INCREASE AS ANOTHER UPPER LEVEL
DISTURBANCE BEGINS TO APPROACH CENTRAL HIGH PLAINS FROM THE
NORTHWEST. A SURFACE BOUNDARY WILL MOVE SOUTH/SOUTHWEST ACROSS
NORTH CENTRAL KANSAS OVERNIGHT WITH SOME INCREASING MOISTURE AND
LIFT DEVELOPING NORTH OF THIS BOUNDARY. THIS MAY GIVE RISE TO A
FEW FLURRIES TOWARDS DAYBREAK. AT THIS TIME GIVEN WHERE THIS
SURFACE BOUNDARY IS EXPECTED TO BE LOCATED TOWARDS 12Z TUESDAY
WILL KEEP A MENTION THE SLIGHT CHANCE FOR LIGHT SNOW GOING ACROSS
MAINLY NORTH CENTRAL KANSAS. WITH THE INCREASING CLOUDS TONIGHT
HAVE DECIDED TO STAY CLOSE TO THE LATEST GUIDANCE WITH
TEMPERATURES FALLING BACK TO AROUND 20 DEGREES.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 146 PM CST SUN FEB 15 2015
ANOTHER WEAK SHORTWAVE IS PROGGED TO THE AREA MONDAY NIGHT INTO
TUESDAY INCREASING LIFT ACROSS THE AREA. THIS FEATURE WILL ALSO
PUSH DOWN ANOTHER SHOT OF ARCTIC AIR INTO WESTERN KANSAS. MOSTLY
CLOUDY SKIES ARE ANTICIPATED MONDAY NIGHT WITH A SLIGHT CHANCE OF
LIGHT SNOW ACROSS CENTRAL KANSAS ON TUESDAY. LITTLE TO NO
ACCUMULATION IS EXPECTED WITH THIS SYSTEM. CLOUDS DECREASE IN
COVERAGE TUESDAY NIGHT WITH PARTLY CLOUDY SKIES EXPECTED THROUGH
FRIDAY. THIS IS DUE TO THE UPPER LEVEL RIDGE BUILDING ACROSS THE
WESTERN UNITED STATES. THE NEXT SET OF SHORTWAVES MOVE THROUGH THE
AREA THIS WEEKEND INCREASING CLOUD COVERAGE AS WELL AS INCREASING
THE CHANCE OF PRECIPITATION. HIGHS TUESDAY AND WEDNESDAY LOOK TO
RANGE FROM THE UPPER 30S ACROSS CENTRAL KANSAS TO UPPER 40S ACROSS
FAR SOUTHWESTERN KANSAS WITH LOWS RANGING FROM THE UPPER TEENS
ACROSS CENTRAL KANSAS TO UPPER 20S ACROSS FAR SOUTHWESTERN KANSAS.
HIGHS SLOWLY REACH INTO THE 50S BY FRIDAY AFTERNOON WITH LOWS IN
THE UPPER 20S AND LOWER 30S. COOLER TEMPERATURES ARE EXPECTED THIS
WEEKEND WITH HIGHS IN THE 40S SATURDAY AND UPPER 30S SUNDAY. LOWS
WILL GENERALLY BE IN THE 20S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1105 PM CST SUN FEB 15 2015
IFR CEILINGS AND LIFR VISIBILITIES CAN BE EXPECTED WITH A BAND OF
STEADY SNOW WHICH WILL BE CROSSING SOUTHWEST KANSAS THROUGH 12Z
MONDAY. THIS IS BASED ON 04Z SURFACE OBSERVATIONS CURRENTLY IN
THE BAND OF STEADIER SNOWFALL ALONG WITH THE AGREEMENT BETWEEN THE
00Z NAM BUFR SOUNDINGS AND LATEST HRRR. THE NAM AND HRRR ALSO
INDICATED THAT THE BETTER CHANCES FOR THESE LOW IFR/LIFR
CONDITIONS WILL OCCUR AT HYS THROUGH 07Z, GCK BETWEEN 06 AND 08Z,
AND THEN DDC BETWEEN 08Z AND 11Z. OUTSIDE THIS AREA OF STEADY
SNOWFALL MVFR CONDITIONS CAN BE EXPECTED THROUGH LATE MORNING.
AFTER 18Z MONDAY THESE LOW CLOUD ARE FORECAST TO GIVE WAY TO VFR
CONDITIONS AS AN UPPER LEVEL TROUGH THAT WILL BE CROSSES WESTERN
KANSAS. WINDS ACROSS WESTERN KANSAS WILL BE NORTH NORTHWEST AT 10
KNOTS OR LESS.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 36 21 43 20 / 20 10 10 0
GCK 38 19 42 19 / 10 10 10 0
EHA 38 22 42 22 / 30 10 10 0
LBL 37 21 44 21 / 20 10 10 0
HYS 38 21 38 16 / 10 20 20 0
P28 37 22 42 19 / 40 10 20 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BURGERT
LONG TERM...HOVORKA_42
AVIATION...BURGERT
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1108 PM CST SUN FEB 15 2015
...UPDATED SYNOPSIS AND AVIATION DISCUSSION...
.SYNOPSIS...
ISSUED AT 1105 PM CST SUN FEB 15 2015
AT 00Z MONDAY A 500MB -24C TROUGH WAS LOCATED OVER THE CENTRAL
ROCKIES. 90 TO 110 METER 12HOUR 500MB HEIGHT FALLS WE OBSERVED
JUST EAST OF THIS UPPER TROUGH FROM DENVER TO NORTH PLATTE AND
DODGE CITY. AHEAD OF THIS UPPER TROUGH A 700MB BAROCLINIC ZONE
EXTENDED FROM EXTREME NORTHEAST NEW MEXICO TO NORTHWEST MISSOURI.
THE 850MB COLD FRONT STRETCHED FROM THE PANHANDLE OF TEXAS INTO
SOUTHERN MISSOURI AT 00Z MONDAY. AN AREA OF BETTER 850MB MOISTURE
WAS LOCATED JUST BEHIND THE COLD FRONT AND ANOTHER AREA APPEARING
ACROSS NORTHWEST NEBRASKA BASED ON NORTH PLATTE SOUNDINGS. ACROSS
WESTERN KANSAS EARLIER THIS MORNING THE DODGE CITY SOUNDINGS
INDICATED THAT THE MOIST LAYER WAS LOCATED BETWEEN THE 800MB AND
700MB LEVEL WITH A DECENT DRY LAYER LOCATED NEAR THE SURFACE.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 136 PM CST SUN FEB 15 2015
A QUICK HITTING UPPER LEVEL SHORTWAVE TROUGH WILL BE MOVING INTO
WESTERN KANSAS TONIGHT, FROM THE INTERMOUNTAIN WEST, THEN EXIT BY
MORNING. THIS SYSTEM WILL BRING SOME LIGHT ACCUMULATING SNOW TO MOST
OF SOUTHWEST AND SOUTH CENTRAL KANSAS WITH AROUND AN INCH EXPECTED.
ALSO WILL REINFORCE THE COLD AIRMASS INTO KANSAS. NORTHEAST WINDS
WILL BECOME NORTHWEST TOWARDS MORNING AT AROUND 10 MPH WITH
OVERNIGHT LOWS IN THE UPPER TEENS TO LOWER 20S. LIGHT SNOW SHOULD
BEGIN FIRST IN THE I-70 CORRIDOR LATE THIS AFTERNOON AND EARLY
EVENING, THEN DROP SOUTHWARD INTO THE REST OF WESTERN KANSAS BY
AROUND MIDNIGHT TO 3 AM, THEN END BY AROUND 8 TO 10 AM AT MEDICINE
LODGE. MODELS ALL IN FAIRLY GOOD AGREEMENT OF AROUND AN INCH
ACCUMULATIONS WITH SOME 700 MB FRONTOGENESIS AND UPWARD MOTION
WITH THE SHORTWAVE. NEW HPC GUIDANCE ALSO IN LINE WITH CURRENT
FORECAST.
FOR MONDAY, SUBSIDENCE IN BACK OF THE UPPER LEVEL WAVE WILL HELP TO
BREAK OUT A LITTLE SUNSHINE UNDER MOSTLY TO PARTLY CLOUDY SKIES.
LIGHT NORTHWEST WINDS BECOME LIGHT NORTH AROUND 5 TO 10 MPH. HIGHS
WILL BE IN THE MID TO UPPER 30S, WITH THE COOLEST WHERE SOME
RESIDUAL SNOWPACK RESIDES.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 146 PM CST SUN FEB 15 2015
ANOTHER WEAK SHORTWAVE IS PROGGED TO THE AREA MONDAY NIGHT INTO
TUESDAY INCREASING LIFT ACROSS THE AREA. THIS FEATURE WILL ALSO
PUSH DOWN ANOTHER SHOT OF ARCTIC AIR INTO WESTERN KANSAS. MOSTLY
CLOUDY SKIES ARE ANTICIPATED MONDAY NIGHT WITH A SLIGHT CHANCE OF
LIGHT SNOW ACROSS CENTRAL KANSAS ON TUESDAY. LITTLE TO NO
ACCUMULATION IS EXPECTED WITH THIS SYSTEM. CLOUDS DECREASE IN
COVERAGE TUESDAY NIGHT WITH PARTLY CLOUDY SKIES EXPECTED THROUGH
FRIDAY. THIS IS DUE TO THE UPPER LEVEL RIDGE BUILDING ACROSS THE
WESTERN UNITED STATES. THE NEXT SET OF SHORTWAVES MOVE THROUGH THE
AREA THIS WEEKEND INCREASING CLOUD COVERAGE AS WELL AS INCREASING
THE CHANCE OF PRECIPITATION. HIGHS TUESDAY AND WEDNESDAY LOOK TO
RANGE FROM THE UPPER 30S ACROSS CENTRAL KANSAS TO UPPER 40S ACROSS
FAR SOUTHWESTERN KANSAS WITH LOWS RANGING FROM THE UPPER TEENS
ACROSS CENTRAL KANSAS TO UPPER 20S ACROSS FAR SOUTHWESTERN KANSAS.
HIGHS SLOWLY REACH INTO THE 50S BY FRIDAY AFTERNOON WITH LOWS IN
THE UPPER 20S AND LOWER 30S. COOLER TEMPERATURES ARE EXPECTED THIS
WEEKEND WITH HIGHS IN THE 40S SATURDAY AND UPPER 30S SUNDAY. LOWS
WILL GENERALLY BE IN THE 20S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1105 PM CST SUN FEB 15 2015
IFR CEILINGS AND LIFR VISIBILITIES CAN BE EXPECTED WITH A BAND OF
STEADY SNOW WHICH WILL BE CROSSING SOUTHWEST KANSAS THROUGH 12Z
MONDAY. THIS IS BASED ON 04Z SURFACE OBSERVATIONS CURRENTLY IN
THE BAND OF STEADIER SNOWFALL ALONG WITH THE AGREEMENT BETWEEN THE
00Z NAM BUFR SOUNDINGS AND LATEST HRRR. THE NAM AND HRRR ALSO
INDICATED THAT THE BETTER CHANCES FOR THESE LOW IFR/LIFR
CONDITIONS WILL OCCUR AT HYS THROUGH 07Z, GCK BETWEEN 06 AND 08Z,
AND THEN DDC BETWEEN 08Z AND 11Z. OUTSIDE THIS AREA OF STEADY
SNOWFALL MVFR CONDITIONS CAN BE EXPECTED THROUGH LATE MORNING.
AFTER 18Z MONDAY THESE LOW CLOUD ARE FORECAST TO GIVE WAY TO VFR
CONDITIONS AS AN UPPER LEVEL TROUGH THAT WILL BE CROSSES WESTERN
KANSAS. WINDS ACROSS WESTERN KANSAS WILL BE NORTH NORTHWEST AT 10
KNOTS OR LESS.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 18 36 23 43 / 90 10 10 10
GCK 19 38 21 42 / 80 10 10 10
EHA 22 38 24 42 / 80 10 10 10
LBL 20 37 24 44 / 80 10 10 10
HYS 15 38 22 38 / 70 10 20 20
P28 17 37 23 42 / 70 30 20 20
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BURGERT
SHORT TERM...KRUSE
LONG TERM...HOVORKA_42
AVIATION...BURGERT
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1000 PM MST SUN FEB 15 2015
.UPDATE...
ISSUED AT 1000 PM MST SUN FEB 15 2015
PRECIPITATION QUICKLY COMING TO AN END FROM NORTH TO SOUTH THIS
EVENING AS MUCH DRIER AIR MOVES IN. FORECAST AREA SHOULD BE CLEAR
OF PRECIP A FEW HOURS AFTER MIDNIGHT. PER MODEL BOUNDARY LAYER RH
AND VISIBILITY FORECASTS HAVE ADDED PATCHY FREEZING FOG TO THE
WESTERN 1/2 OF THE AREA.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 211 PM MST SUN FEB 15 2015
MAIN FOCUS IN THE SHORT TERM CONTINUES TO BE ON SNOW POTENTIAL THIS
AFTERNOON THROUGH MONDAY AS SHORTWAVE TROUGH CURRENTLY OVER WESTERN
COLORADO/NORTHERN NEW MEXICO SLOWLY EJECTS ACROSS THE PLAINS.
MOST 12Z GUIDANCE (NAM/GFS) AND LATEST SHORT RANGE GUIDANCE
(RAP/HRRR) SEEM TO HAVE BETTER HANDLE ON LOCATION/TIMING OF CURRENT
PRECIP OVER COLORADO/WESTERN NEBRASKA AND HAVE SLOWED DOWN ONSET
OVER OUR CWA. WHILE THERE IS WEAK FORCING PRESENT AND LIGHT RETURNS
ON RADAR OVER OUR NORTHERN CWA...THIS HAS STRUGGLED TO OVERCOME A
1500-2000 KFT SUB CLOUD DRY LAYER WITH AVERAGE TD DEPRESSIONS 15-
20F. AS SHORTWAVE FINAL BEGINS TO EJECT EASTWARD STRONGER FORCING
AND BETTER LOW LEVEL MOISTURE RETURN WILL ALLOW FOR INCREASE IN SNOW
COVERAGE FROM THE WEST TO THE EAST. I COULD STILL SEE SOME SNOW
BEFORE THIS...BUT HIGHER CONFIDENCE IS FOR AFTER 00Z. LOOKS LIKE WE
SHOULD HAVE A BAND FORM OVER EASTERN COLORADO AND MOVE TOWARDS THE
I70 CORRIDOR BEFORE SLIDING SOUTH AROUND MIDNIGHT. GUIDANCE IS STILL
SHOWING SOME WEAK FORCING IN THE WEST AND LIGHT PRECIP SIGNAL. NOT A
LOT OF CONFIDENCE IN THIS AS WE APPEAR TO BE ON SUBSIDENT SIDE OF H3
JET. MODELS ARE STILL SHOWING SOME WEAK MID LEVEL VORTICITY AND A
LIGHT PRECIP SIGNAL IN THE WEST...SO I KEPT SLIGHT CHANCE/CHANCE IN
PLACE FOR NOW. BASED ON CURRENT TIMING AND HIGHEST CONFIDENCE IS
APPEARS WE COULD SEE A QUICK INCH (MAYBE A LITTLE MORE) WITH THE
SNOW THIS EVENING...WITH HRRR/RAP POSSIBLY SUPPORTING RATES OF 0.5"
PER HOUR. THE PROGRESSIVE NATURE OF THE BAND WILL BE THE LIMITING
FACTOR ON AMOUNTS...WHERE IF IT LINGERS COULD RESULT IN ISOLATED 2-
3" TOTALS. OTHERWISE I WOULD ONLY ANTICIPATE A DUSTING OF ADDITIONAL
SNOW AFTER MIDNIGHT THROUGH MONDAY IF THERE IS ANY SNOW LINGERING AT
THAT POINT. NOT ANTICIPATING ADVISORY LEVEL SNOWS AT THIS
POINT...AND THREAT FOR THAT SEEMS TO BE VERY NARROW/ISOLATED IN OUR
SW.
WHILE THERE WILL BE A SLIGHT INCREASE IN WINDS DURING THE DAY MONDAY
(10-15 MPH GUSTING 20 MPH) THIS LIKELY WONT BE ENOUGH TO CAUSE
MAJOR DRIFTING OR VISIBILITY REDUCTIONS ON ITS OWN. HIGH TEMPS WILL
BE TRICKY WITH A SLIGHT MODERATION OF TEMPS ALOFT MONDAY...FIGHTING
LIMITED DIURNAL HEATING DUE TO CLOUD COVER. BEST CHANCE FOR BREAKS
IN SKY COVER WILL BE IN THE NORTHEAST...WHERE IF THEY DO SEE SOME
SUNSHINE COULD REACH THE LOWER 40S. IF STRATUS LINGER...MOST WONT
SEE HIGHS OUT OF THE 30S.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 200 PM MST SUN FEB 15 2015
IN THE EXTENDED PERIOD...BOTH THE LATEST GFS AND ECMWF RUNS CONTINUE
TO SHOW H5 RIDGE MEANDERING ALONG OR JUST OFF THE PACIFIC
COAST...WITH BROAD UPPER LOW CIRCULATION OVER MUCH OF THE UNITED
STATES/CANADA. AROUND THIS LOW SEVERAL SHORTWAVES WILL PINWHEEL
SOUTH AND EAST ACROSS THE PLAINS REGION...GIVING THE AREA A CHANCE
FOR LIGHT PRECIPITATION. THE REMNANTS OF THE CURRENT LATE WEEKEND
SYSTEM WILL FINALLY TAPER OFF OVER THE SW PORTION OF THE CWA MONDAY
NIGHT BEFORE SECOND SHORTWAVE DIVES OVER THE REGION ON TUESDAY. DRY
CONDITIONS WILL RETURN TUESDAY NIGHT INTO FRIDAY...BUT A POTENTIAL
PROLONGED SYSTEM COULD AFFECT THE REGION FRIDAY NIGHT ON INTO NEXT
WEEKEND. THIS SYSTEM WILL DIVE OUT OF THE PACIFIC NORTHWEST AS MID
LEVEL FLOW BACKS MORE TOWARDS THE NORTHWEST DURING THIS TIME.
TEMPERATURES IN THE EXTENDED...CAA WILL ARRIVE IN TANDEM WITH THE
SECOND SHORTWAVE DURING THE DAY TUESDAY AND THEN AGAIN OVER THE
UPCOMING WEEKEND WITH THE ARRIVAL OF THE DEEP SHORTWAVE TROUGH.
TUESDAY/S HIGHS WILL ONLY REACH INTO THE 30S BEFORE WARMING SLIGHTLY
IN TO THE 40S TO LOW TO MID 50S BY THURSDAY INTO FRIDAY AHEAD OF
NEXT SYSTEM. THIS WILL BE AIDED BY SURFACE HIGH PRESSURE OFF TO OUR
EAST...AND A LEE-SIDE TROUGH TO OUR WEST THAT WILL SET UP WAA. BY
NEXT WEEKEND... BELOW NORMAL TEMPS WILL SET UPON THE TRI STATE
REGION WITH HIGHS IN THE 30S. OVERNIGHT LOWS WILL RANGE IN THE TEENS
TO L20S.
WINDS IN THE EXTENDED...TUESDAY SEEMS TO BE THE MAIN DAY TO SEE
STRONG WINDS OVER THE AREA AS A JET COINCIDES WITH PASSAGE OF
SHORTWAVE. LATEST BUFKIT SOUNDINGS DO SUGGEST MIXING UP TO 650-700MB
WHERE TUESDAY AFTERNOON HRS COULD HAVE STEADY 30-40MPH WITH GUSTS 50-
55MPH...WHICH WILL COME CLOSE TO HIGH WIND CRITERIA...SO WILL HAVE
TO BE WATCHED. THE OTHER TIMEFRAME FOR POTENTIAL WINDY CONDITIONS
WILL BE OVER NEXT WEEKEND WHERE GUSTS 20-30MPH COULD ACCOMPANY BROAD
SHORTWAVE.
PRECIPITATION IN THE EXTENDED...MAIN P-TYPE WILL BE LIGHT
SNOW/SNOWSHOWERS. HOWEVER...DAYTIME TEMPS ON TUESDAY AND AGAIN WITH
THE SYSTEM OVER NEXT WEEKEND COULD ALLOW FOR SOME LIGHT
RAIN/RAINSHOWERS TO MIX INTO WX SITUATION. GOING FOR OVERALL LIGHT
ACCUM TOTALS IN THE INCH OR SO RANGE WITH LOW QPF.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1000 PM MST SUN FEB 15 2015
KGLD...VFR CONDITIONS EXPECTED THROUGH THE PERIOD. NORTHWEST WINDS
UNDER 10KTS AT TAF ISSUANCE EXPECTED TO CONTINUE THROUGH 19Z
BEFORE INCREASING TO 12KTS FROM 20Z-23Z. AFTER 23Z WINDS SLOWLY
BACK TO THE WEST-SOUTHWEST NEAR 10KTS. CLOUDINESS PRIMARILY MID
AND UPPER LEVELS. WILL HAVE TO WATCH FOR SOME MVFR CLOUDINESS FROM
TAF ISSUANCE THROUGH 15Z PER NAM AND LESSER EXTENT RUC MOISTURE
CROSS-SECTIONS. MODELS ALSO RATHER PERSISTENT IN PRODUCING SOME
FOG/MIST DURING THE SAME TIME PERIOD. WITH KITR RECENTLY DROPPING
TO IFR CIGS WILL BEGIN THE PERIOD WITH A TEMPO GROUP FOR IFR CIGS.
KMCK...VFR CONDITIONS EXPECTED THROUGH THE PERIOD. LIGHT/VARIABLE
WINDS AT TAF ISSUANCE EXPECTED TO BECOME NORTHWEST AROUND 6KTS BY
09Z THEN 13KTS FROM 20Z-22Z BEFORE DECREASING TO 10KTS BY 23Z.
WEST-NORTHWEST WINDS AROUND 7KTS EXPECTED AFTER 05Z. CLOUDINESS
CONFINED TO MID AND UPPER LEVELS THROUGH 19Z BEFORE DECREASING BUT
REMAINING VFR FOR THE REST OF THE TAF PERIOD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...99
SHORT TERM...DR
LONG TERM...JN
AVIATION...99
AREA FORECAST DISCUSSION
NWS CARIBOU ME
1229 AM EST MON FEB 16 2015
.SYNOPSIS...
AN INTENSE AREA OF LOW PRESSURE WILL LIFT NORTH OF NOVA SCOTIA
OVERNIGHT. HIGH PRESSURE ACROSS THE MIDWEST WILL BUILD TOWARD THE
REGION THROUGH TUESDAY MORNING. LOW PRESSURE WILL PASS SOUTH OF
THE AREA TUESDAY. ANOTHER LOW WILL DEVELOP IN THE GULF OF MAINE
WEDNESDAY.
&&
.NEAR TERM /THROUGH TODAY/...
1220 AM UPDATE: HEADLINES WILL REMAIN IN PLACE AS IS FOR THIS
UPDATE. WRAP AROUND SNOW OCCURRING ACROSS NORTHERN AND EASTERN
MAINE AND W/THE STRONG WIND GUSTS, WIDESPREAD BLOWING AND DRIFTING
OCCURRING. THE 03Z RUN OF THE RAP AND NAM12 APPEARED TO HAVE A
GOOD HANDLE ON THE PRECIP SHIELD. 04Z SURFACE ANALYSIS SHOWED
TIGHT PRES GRADIENT AS INTENSE LOW PRESSLOWLY LIFT NORTH ACROSS
THE MARITIMES. IR SATELLITE IMAGERY HAD SOME EHHANCEMENT ROTATING
BACK ACROSS NORTHERN AND EASTERN MAINE AND BOTH THE NAM AND RAP
SHOW THE PRECIP ASSOCIATED W/THE ENHANCEMENT GRADUALLY LIFTING
NORTH THROUGH THE MORNING AND WEAKENING.
THEREFORE, ADJUSTED THE POPS ACROSS THE NORTHERN AND EASTERN AREAS
TO 80% AND EXPECT ANOTHER INCH OR SO OF SNOW BEFORE IT WINDS DOWN.
WINDS WERE SLIGHTLY ADJUSTED BASED ON THE OBS. 50+ MPH GUST AT
KFVE ABOUT AND HOUR AGO.
WINDS WILL CONTINUE TONIGHT AS THE LOW MOVES INTO THE MARITIMES
WITH GUSTS OVER 40 MPH THROUGH THE NIGHT AND DURING MONDAY. WITH
THE ARCTIC AIR IN PLACE...THIS MEANS THAT ALL OF THE FORECAST AREA
WILL EVENTUALLY NEED WIND CHILL ADVISORIES AS SNOW ENDS. HIGHS ON
MONDAY WILL BE MOSTLY IN THE SINGLE DIGITS AND THE WIND CHILL
ADVISORIES MAY BE IN PLACE ALL DAY. THE WINDS WILL ALSO CAUSE
CONTINUED DRIFTING THROUGH TONIGHT AND MONDAY. REDUCED
VISIBILITIES DUE TO BLOWING SNOW SHOULD NOT BE A FACTOR ONCE THE
SNOW ENDS TONIGHT.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY/...
THE SHORT TERM WILL CONT TO BE BRISK MON EVE AS THE BACK SIDE PRES
GRAD CONTS TO RETREAT FROM THE REGION WITH DEEP LOW PRES MOVG NE
THRU THE NRN CAN MARITIMES. WE WILL LIKELY NEED WIND CHILL HDLNS
THRU MOST OF THE NGT. ANY LEFT OVR CLDNSS AND FLURRIES SHOULD
EXIT ERN PTNS OF THE FA BY LATE MON NGT...AND THEN WINDS SHOULD
SUBSIDE...SPCLY OVR THE NW BY DAYBREAK TUE...ALLOWING FOR A PD OF
RADIATIONAL COOLING AND A SHALLOW ARCTIC SFC BASE INVSN. WE
THEREFORE LOWER FCST LOWS OVR NW VLYS ABOUT 5 OR SO DEG F OVR MON
NGT.
TUE WILL BEGIN FAIR...THEN THE FIRST OF TWO S/WV IMPULSES BRINGS
INCREASING CLDNSS BY TUE AFTN AND A CHC OF LGT SN TO MSLY DOWNEAST AREAS
BY TUE EVE. AFT A BREAK LATE TUE NGT AND WED MORN...THE
SECOND...STRONGER S/WV WILL BRING A BETTER CHC OF SN TO THE REGION
BEGINNING OVR THE SW PTN OF THE FA WED AFTN. TEMPS WILL MODERATE
SOME FROM TUE AFTN THRU WED...BUT STILL SIG BLO AVG FOR THIS TM OF
SEASON.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
LOW PRES IN THE GULF OF MAINE WED EVENING WILL LIFT NORTH WED NIGHT
AND THU. IN THE WAKE OF THE LOW HIGH PRES WILL SLOWLY BUILD TOWARD
THE REGION FROM THE WEST AND WILL CREST ACROSS THE AREA AROUND 12Z
SAT. THE NEXT SYSTEM MOVES IN FROM THE WEST SAT NIGHT AND SUN.
ALOFT A DEEP UPPER TROUGH MOVES THROUGH NEW ENGLAND LATE IN THE
WEEK WITH A BROAD TROUGH ALOFT TO REMAIN ENTRENCHED ACROSS THE
EAST FOR THE FORESEEABLE FUTURE.
AS FAR AS THE SENSIBLE WEATHER GOES...SNOW WILL LIKELY BE MOVING
NORTH ACROSS THE AREA WED NIGHT AND MAY CONTINUE INTO THU MORNING
ACROSS THE CROWN OF MAINE. AT THIS TIME IT DOES NOT LOOK TO BE A
MAJOR SNOW PRODUCER...BUT A FEW INCHES OF SNOW ARE POSSIBLE.
DID GO HIGHER THAN THE MODEL CONSENSUS POPS. IN THE WAKE OF THE
LOW IT WILL REMAIN QUITE COLD THROUGH THE END OF THE WEEK WITH
TEMPERATURES AVERAGING ABOUT 15 DEGREES BELOW SEASONAL AVERAGES.
TEMPERATURES WILL REMAIN BELOW NORMAL THROUGH THE WEEKEND WITH
SOME MODEST MODERATION OF THE AIR MASS SUNDAY. THE HEMISPHERE
MODELS...CFSV2...CIPS ANALOGS...AND CPC 8-14 DAY ALL INDICATE A
COLDER THAN NORMAL PATTERN PERSISTING THROUGH THE END OF THE
MONTH. THIS WILL END UP AS EITHER THE COLDEST OR ONE OF THE
COLDEST FEBRUARIES ON RECORD FOR MANY AREAS IN NORTHERN AND
EASTERN MAINE.
&&
.AVIATION /05Z MONDAY THROUGH FRIDAY/...
NEAR TERM: VFR AT BGR WITH STRONG NW WINDS GUSTING OVER 40 MPH.
ELSEWHERE...IFR CONDITIONS AT BHB WILL END THIS EVENING AND VFR
CONDITIONS WILL COMMENCE. MVFR TEMPO IFR WILL OCCUR AT FVE. IFR
CONDITIONS AT CAR/PQI/HUL WILL END LATER TONIGHT AND GIVE WAY TO
VFR. STRONG NW WINDS GUSTING OVER 40 MPH WILL CONTINUE AT THESE
SITES.
SHORT TERM: GALE CONDITIONS WITH MDT FZG SPY WILL STILL BE IN
PROGRESS MON EVE...WITH WINDS SUBSIDING TO SCA AND FZG SPY TO LGT
INTENSITY BY TUES MORN...WITH A PD OF NO HDLNS XPCTD LATE TUE INTO WED
MORN. SEAS COULD INCREASE TO SCA IN SWELL BY WED EVE. WE WENT
ABOUT 1 TO 2 FT ABV WW3 WV GUIDANCE FOR FCST WV HTS THRU THIS PTN
OF THE FCST.
&&
.MARINE...
NEAR TERM: STORM CONDITIONS AND HEAVY FREEZING SPRAY ARE EXPECTED
THROUGH TONIGHT. HEAVY FREEZING SPRAY CONTINUES MONDAY
MORNING...BUT THE STORM WARNING WILL GIVE WAY TO A GALE WARNING.
SHORT TERM: VFR XPCTD MON NGT INTO TUE MORN...THEN MVFR/IFR CLGS AND
OCNLY VSBYS IN LGT SN XPCTD TUE AFTN THRU WED...MSLY FROM KHUL SWRD
TO KBHB WITH VFR OR MVFR FOR NRN TAF SITES.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR
MEZ002-005-006-011-016-017-029-030-032.
WIND CHILL ADVISORY UNTIL 10 AM EST THIS MORNING FOR MEZ001-
003-004-010-015-031.
MARINE...HEAVY FREEZING SPRAY WARNING UNTIL 11 AM EST THIS MORNING FOR
ANZ050>052.
STORM WARNING UNTIL 7 AM EST THIS MORNING FOR ANZ050>052.
&&
$$
NEAR TERM...HEWITT
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
109 AM CST Mon Feb 16 2015
.UPDATE:
Issued at 1253 AM CST Mon Feb 16 2015
Persistent mesoscale band of snow that has deposited 5 to 8 inches
of snow just north of Interstate 70 late this afternoon into this
evening is finally starting to weaken a bit as the main event gets
underway to the south and southwest. Forecast in really good shape
with convective elements feeding northeast from Oklahoma and
southeast Kansas into southern Missouri. Drawing a line from the
northern edge of this new development to our southwest suggests
that locations along and south of the I-44 (MO)/I-70 (IL) will see
moderate and at times heavy snow for most of the overnight hours
into early Monday morning. Could be a "minimum" of snowfall
between the first band and the heavier snowfall to the south,
generally along the Missouri River from Jefferson City to
Washington Missouri. Even in this minimum area believe storm
totals will be nearly 5 inches by the time all is said and done.
For locations to the north where the band was persistent, expect
a strip of 6 to 10 inches (locally more) from near Columbia
Missouri to Brighton Illinois. Along and south of I-44/I-70
Missouri/Illinois should see widespread amounts of 6 to 10 inches,
with locally higher amounts, especially if some of those
convective elements move across the eastern Ozarks.
Expect to have an update out by 2 am.
Issued at 1005 PM CST Sun Feb 15 2015
Band of snow settling across the I-70 corridor currently was a
couple tiers of counties further to the north earlier this evening
where 3 to 5" of snow has fallen already...roughly from a Paris to
Bowling Green MO line and into Hillsboro IL.
One inch per hour and...at times...greater than that...rates can
be found with this band which will now affect the COU/JEF and STL
metro areas for the next several hours.
In the meantime...moisture rich region over the southern Plains
and into southern MO is developing abundant pcpn currently and
this will begin to affect our southern counties into SE MO and far
S IL late tonight and continue thru Monday morning.
While pcpn types have been a bit more complicated than originally
anticipated due to high layer of warm air aloft...about 8kft...
which has given an initial p-type of sleet or snow pellets for
areas near and south of I-70...the models show a suppression of
this layer to the south with time...and should be south of our
region by 12z Monday morning yielding all snow for types. What
will result though...is lower SLRs for southeast MO and far
southern IL until late tonight. But these snow amounts should be
made up once the pcpn becomes all dendritic snow with decent pcpn
amounts expected to persist there beyond 12z.
The Warning was expanded north to where the band initially set up
to the north and enough forecast snow leftover to yield 6" or so
there, with the main thrust of snow accums still expected to come
for areas further south to justify continuing the warnings there.
TES
&&
.SHORT TERM: (Tonight through Monday Night)
Issued at 255 PM CST Sun Feb 15 2015
All data continues to show a winter storm impacting the area tonight
into Sunday, and the 12z model guidance generally is close to the
previous 00z/06z runs adding to the event confidence. That said
there is still significant uncertainty on aspects of the forecast,
namely where the frontogenetical band will set-up and the snow it
will produce before 06z, and the northern edge of snow thereafter.
The overall scenario has changed little since the previous forecast.
Radar currently shows that the initial snow band is trying to
develop from near KSTJ-KMBY-KSET-KSLO in response to strong mid
level frontogenetical forcing and weak warm advection. I have not
seen any snow reports thus far so we are still in the saturation
process due to dry antecedant low levels. Fronotogenetical forcing
and low level warm advection will ramp-up through the remainder of
this afternoon and especially this evening and the expectation is
that this evolving band will intensify producing moderate snowfall
between the 00-06z period. A blend of available short-term
guidance from the RAP, HRRR and deterministic guidance suggests
the band will become established just north of I-70 and become
more west-east oriented producing ~3 inches by 06z.
After 06z conditions begin to change due to the short-wave digging
southeastward into the central Plains. The response appears to be a
southward shift in the mid level frontogenesis and warm advection
supporting this northern band, and increasing large scale ascent
with a vort max head of trof and the backbuilding ULJ. Thus after
06z the primary forcing and ascent shifts southward along and south
of I-70. This would suggest that the northern snow band will fade
while a new and much larger swath of snow spreads/develops across
the southern half of MO/IL. This will place the I-70 corridor on the
northern part of the snow shield and could play havoc with amounts
along the I-70 corridor where the greatest uncertainty in the
forecast resides. Large scale ascent with the migrating short wave
trof and mid level frontogenesis will keep the heart of the snow band
focused south of I-70 across southern MO and southern IL on Sunday
morning with Columbia-St. Louis-Vandalia IL still on the northern
periphery of the deformation snow shield. By mid-late afternoon the
forcing will exit to the east of the area in association with the
migrating short wave trof, bringing and end to the snowfall.
Despite the very cold temperatures and dry nature of the snow, the
sounding profiles continue to show a shallow dendritic growth zone
with much larger profiles supporting columns and plates within the
lift zone. This suggests snow ratios closer to 13-15:1.
The new forecast is not far from the previous one but is a bit lower
in snow totals along I-70 with 5-7 inches due to the uncertainties
discussed, but still looking at 8+ southeast MO into southern IL.
This forecast will need to be further refined this evening in
anticipation of the northern frontogenetic snow band.
No changes needed to the previously issued winter storm watch and
advisories.
Glass
.LONG TERM: (Tuesday through Next Sunday)
Issued at 255 PM CST Sun Feb 15 2015
A cold front wil move southeastward through our forecast area on
Tuesday as a broad positively tilted upper level trough gradually
deepens over the region. There may be some post fronal light snow
Tuesday and Tuesday night, mainly across central and southeast MO
and southwest IL. A secondary cold front will drop southeastward
through our area late Tuesday night and Wednesday morning. Very
cold air is expected to invade our forecast area behind this second
front as a strong surface ridge bulds southeastward into MO from the
northern Plains. The models drop the -24 degree C 850 mb isotherm
southward to near STL on Wednesday. Temperatures on Wednesday and
Wednesday night should be close to 30 degrees below normal due to
this very cold air mass along with snow cover across most of the
forecast area from the recent winter storm. A warming trend should
begin Thursday night due to rising upper level heights along with
surface winds becoming southerly as the surface ridge shifts east of
our area. There may be some light snow Thursday night and Friday,
mainly across southeast MO and southwest IL, due to low-mid level
warm air advection. There will be a better chance of more
significant precipitation Friday night through Sunday as a cold
front sags southward into the area and a southern stream shortwave
approaches. Precipitation type will be in question along and ahead
of the cold front, but should be all snow by Saturday night or
Sunday as another cold air mass drops southward through our area
behind the front.
GKS
&&
.AVIATION: (For the 06z TAFs through 06z Monday Night)
Issued at 1137 PM CST Sun Feb 15 2015
Band of moderate to occasionally heavy snow just north of I-70
will continue to sink slowly south through the night.
Additionally, sleet and snow will fill in across southeast
Missouri as well. Lighter snow will continue across northern
Missouri and west central Illinois ending toward daybreak. IFR
flight conditions will likely prevail across most of the area
while precipitation continues. Expect improving conditions over
northeast Missouri and west central Illinois as snow tapers off
and finally ends later tonight. Snow will taper off and end from
west to east across central and eastern Missouri into southwest
Illinois from mid morning into early afternoon. Flight conditions
will improve during the morning, but still think that MVFR
ceilings will hang around for most of the day. May see ceilings
scatter out during the evening, but guidance does keep the lower
atmosphere pretty moist so confidence in clearing sky is low.
Specifics for KSTL:
The band of moderate to occasionally heavy snow has been flirting
with the 10nm range ring to the north of Lambert for much of the
evening. However, it should continue to progress slowly south, and
areas of snow will continue to move in from the west and southwest
through the remainder of the night as well. Expect that IFR
conditions will prevail with visibilities near or just above
airport minimums. Think there will be breaks in the heavier snow,
but am not confident in how long/how much improvement there will
be during these breaks. Heavier snow should be tapering off after
12Z and ending completely sometime between 17Z and 20Z. Still
think MVFR ceilings will continue to prevail after the snow ends. May
see ceilings scatter out during the evening, but guidance does
keep the lower atmosphere pretty moist so confidence in clearing
sky is low.
Carney
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER STORM WARNING until 6 PM CST this evening FOR Audrain MO-
Boone MO-Callaway MO-Cole MO-Crawford MO-Franklin MO-
Gasconade MO-Iron MO-Jefferson MO-Lincoln MO-Madison MO-
Moniteau MO-Monroe MO-Montgomery MO-Osage MO-Pike MO-Ralls
MO-Reynolds MO-St. Charles MO-St. Francois MO-St. Louis
City MO-St. Louis MO-Ste. Genevieve MO-Warren MO-Washington
MO.
WINTER WEATHER ADVISORY until 6 PM CST this evening FOR Marion
MO-Shelby MO.
IL...WINTER STORM WARNING until 6 PM CST this evening FOR Bond IL-
Calhoun IL-Clinton IL-Fayette IL-Greene IL-Jersey IL-
Macoupin IL-Madison IL-Marion IL-Monroe IL-Montgomery IL-
Randolph IL-St. Clair IL-Washington IL.
WINTER WEATHER ADVISORY until 6 PM CST this evening FOR Pike IL.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1157 PM CST Sun Feb 15 2015
.UPDATE:
Issued at 1005 PM CST Sun Feb 15 2015
Band of snow settling across the I-70 corridor currently was a
couple tiers of counties further to the north earlier this evening
where 3 to 5" of snow has fallen already...roughly from a Paris to
Bowling Green MO line and into Hillsboro IL.
One inch per hour and...at times...greater than that...rates can
be found with this band which will now affect the COU/JEF and STL
metro areas for the next several hours.
In the meantime...moisture rich region over the southern Plains
and into southern MO is developing abundant pcpn currently and
this will begin to affect our southern counties into SE MO and far
S IL late tonight and continue thru Monday morning.
While pcpn types have been a bit more complicated than originally
anticipated due to high layer of warm air aloft...about 8kft...
which has given an initial p-type of sleet or snow pellets for
areas near and south of I-70...the models show a suppression of
this layer to the south with time...and should be south of our
region by 12z Monday morning yielding all snow for types. What
will result though...is lower SLRs for southeast MO and far
southern IL until late tonight. But these snow amounts should be
made up once the pcpn becomes all dendritic snow with decent pcpn
amounts expected to persist there beyond 12z.
The Warning was expanded north to where the band initially set up
to the north and enough forecast snow leftover to yield 6" or so
there, with the main thrust of snow accums still expected to come
for areas further south to justify continuing the warnings there.
TES
&&
.SHORT TERM: (Tonight through Monday Night)
Issued at 255 PM CST Sun Feb 15 2015
All data continues to show a winter storm impacting the area tonight
into Sunday, and the 12z model guidance generally is close to the
previous 00z/06z runs adding to the event confidence. That said
there is still significant uncertainty on aspects of the forecast,
namely where the frontogenetical band will set-up and the snow it
will produce before 06z, and the northern edge of snow thereafter.
The overall scenario has changed little since the previous forecast.
Radar currently shows that the initial snow band is trying to
develop from near KSTJ-KMBY-KSET-KSLO in response to strong mid
level frontogenetical forcing and weak warm advection. I have not
seen any snow reports thus far so we are still in the saturation
process due to dry antecedant low levels. Fronotogenetical forcing
and low level warm advection will ramp-up through the remainder of
this afternoon and especially this evening and the expectation is
that this evolving band will intensify producing moderate snowfall
between the 00-06z period. A blend of available short-term
guidance from the RAP, HRRR and deterministic guidance suggests
the band will become established just north of I-70 and become
more west-east oriented producing ~3 inches by 06z.
After 06z conditions begin to change due to the short-wave digging
southeastward into the central Plains. The response appears to be a
southward shift in the mid level frontogenesis and warm advection
supporting this northern band, and increasing large scale ascent
with a vort max head of trof and the backbuilding ULJ. Thus after
06z the primary forcing and ascent shifts southward along and south
of I-70. This would suggest that the northern snow band will fade
while a new and much larger swath of snow spreads/develops across
the southern half of MO/IL. This will place the I-70 corridor on the
northern part of the snow shield and could play havoc with amounts
along the I-70 corridor where the greatest uncertainty in the
forecast resides. Large scale ascent with the migrating short wave
trof and mid level frontogenesis will keep the heart of the snow band
focused south of I-70 across southern MO and southern IL on Sunday
morning with Columbia-St. Louis-Vandalia IL still on the northern
periphery of the deformation snow shield. By mid-late afternoon the
forcing will exit to the east of the area in association with the
migrating short wave trof, bringing and end to the snowfall.
Despite the very cold temperatures and dry nature of the snow, the
sounding profiles continue to show a shallow dendritic growth zone
with much larger profiles supporting columns and plates within the
lift zone. This suggests snow ratios closer to 13-15:1.
The new forecast is not far from the previous one but is a bit lower
in snow totals along I-70 with 5-7 inches due to the uncertainties
discussed, but still looking at 8+ southeast MO into southern IL.
This forecast will need to be further refined this evening in
anticipation of the northern frontogenetic snow band.
No changes needed to the previously issued winter storm watch and
advisories.
Glass
.LONG TERM: (Tuesday through Next Sunday)
Issued at 255 PM CST Sun Feb 15 2015
A cold front wil move southeastward through our forecast area on
Tuesday as a broad positively tilted upper level trough gradually
deepens over the region. There may be some post fronal light snow
Tuesday and Tuesday night, mainly across central and southeast MO
and southwest IL. A secondary cold front will drop southeastward
through our area late Tuesday night and Wednesday morning. Very
cold air is expected to invade our forecast area behind this second
front as a strong surface ridge bulds southeastward into MO from the
northern Plains. The models drop the -24 degree C 850 mb isotherm
southward to near STL on Wednesday. Temperatures on Wednesday and
Wednesday night should be close to 30 degrees below normal due to
this very cold air mass along with snow cover across most of the
forecast area from the recent winter storm. A warming trend should
begin Thursday night due to rising upper level heights along with
surface winds becoming southerly as the surface ridge shifts east of
our area. There may be some light snow Thursday night and Friday,
mainly across southeast MO and southwest IL, due to low-mid level
warm air advection. There will be a better chance of more
significant precipitation Friday night through Sunday as a cold
front sags southward into the area and a southern stream shortwave
approaches. Precipitation type will be in question along and ahead
of the cold front, but should be all snow by Saturday night or
Sunday as another cold air mass drops southward through our area
behind the front.
GKS
&&
.AVIATION: (For the 06z TAFs through 06z Monday Night)
Issued at 1137 PM CST Sun Feb 15 2015
Band of moderate to occasionally heavy snow just north of I-70
will continue to sink slowly south through the night.
Additionally, sleet and snow will fill in across southeast
Missouri as well. Lighter snow will continue across northern
Missouri and west central Illinois ending toward daybreak. IFR
flight conditions will likely prevail across most of the area
while precipitation continues. Expect improving conditions over
northeast Missouri and west central Illinois as snow tapers off
and finally ends later tonight. Snow will taper off and end from
west to east across central and eastern Missouri into southwest
Illinois from mid morning into early afternoon. Flight conditions
will improve during the morning, but still think that MVFR
ceilings will hang around for most of the day. May see ceilings
scatter out during the evening, but guidance does keep the lower
atmosphere pretty moist so confidence in clearing sky is low.
Specifics for KSTL:
The band of moderate to occasionally heavy snow has been flirting
with the 10nm range ring to the north of Lambert for much of the
evening. However, it should continue to progress slowly south, and
areas of snow will continue to move in from the west and southwest
through the remainder of the night as well. Expect that IFR
conditions will prevail with visibilities near or just above
airport minimums. Think there will be breaks in the heavier snow,
but am not confident in how long/how much improvement there will
be during these breaks. Heavier snow should be tapering off after
12Z and ending completely sometime between 17Z and 20Z. Still
think MVFR ceilings will continue to prevail after the snow ends. May
see ceilings scatter out during the evening, but guidance does
keep the lower atmosphere pretty moist so confidence in clearing
sky is low.
Carney
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER STORM WARNING until 6 PM CST Monday FOR Audrain MO-Boone
MO-Callaway MO-Cole MO-Crawford MO-Franklin MO-Gasconade MO-
Iron MO-Jefferson MO-Lincoln MO-Madison MO-Moniteau MO-
Monroe MO-Montgomery MO-Osage MO-Pike MO-Ralls MO-Reynolds
MO-St. Charles MO-St. Francois MO-St. Louis City MO-St.
Louis MO-Ste. Genevieve MO-Warren MO-Washington MO.
WINTER WEATHER ADVISORY until 6 PM CST Monday FOR Marion MO-
Shelby MO.
IL...WINTER STORM WARNING until 6 PM CST Monday FOR Bond IL-Calhoun
IL-Clinton IL-Fayette IL-Greene IL-Jersey IL-Macoupin IL-
Madison IL-Marion IL-Monroe IL-Montgomery IL-Randolph IL-
St. Clair IL-Washington IL.
WINTER WEATHER ADVISORY until 6 PM CST Monday FOR Pike IL.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
1022 PM CST Sun Feb 15 2015
.UPDATE:
Issued at 1005 PM CST Sun Feb 15 2015
Band of snow settling across the I-70 corridor currently was a
couple tiers of counties further to the north earlier this evening
where 3 to 5" of snow has fallen already...roughly from a Paris to
Bowling Green MO line and into Hillsboro IL.
One inch per hour and...at times...greater than that...rates can
be found with this band which will now affect the COU/JEF and STL
metro areas for the next several hours.
In the meantime...moisture rich region over the southern Plains
and into southern MO is developing abundant pcpn currently and
this will begin to affect our southern counties into SE MO and far
S IL late tonight and continue thru Monday morning.
While pcpn types have been a bit more complicated than originally
anticipated due to high layer of warm air aloft...about 8kft...
which has given an initial p-type of sleet or snow pellets for
areas near and south of I-70...the models show a suppression of
this layer to the south with time...and should be south of our
region by 12z Monday morning yielding all snow for types. What
will result though...is lower SLRs for southeast MO and far
southern IL until late tonight. But these snow amounts should be
made up once the pcpn becomes all dendritic snow with decent pcpn
amounts expected to persist there beyond 12z.
The Warning was expanded north to where the band initially set up
to the north and enough forecast snow leftover to yield 6" or so
there, with the main thrust of snow accums still expected to come
for areas further south to justify continuing the warnings there.
TES
&&
.SHORT TERM: (Tonight through Monday Night)
Issued at 255 PM CST Sun Feb 15 2015
All data continues to show a winter storm impacting the area tonight
into Sunday, and the 12z model guidance generally is close to the
previous 00z/06z runs adding to the event confidence. That said
there is still significant uncertainty on aspects of the forecast,
namely where the frontogenetical band will set-up and the snow it
will produce before 06z, and the northern edge of snow thereafter.
The overall scenario has changed little since the previous forecast.
Radar currently shows that the initial snow band is trying to
develop from near KSTJ-KMBY-KSET-KSLO in response to strong mid
level frontogenetical forcing and weak warm advection. I have not
seen any snow reports thus far so we are still in the saturation
process due to dry antecedant low levels. Fronotogenetical forcing
and low level warm advection will ramp-up through the remainder of
this afternoon and especially this evening and the expectation is
that this evolving band will intensify producing moderate snowfall
between the 00-06z period. A blend of available short-term
guidance from the RAP, HRRR and deterministic guidance suggests
the band will become established just north of I-70 and become
more west-east oriented producing ~3 inches by 06z.
After 06z conditions begin to change due to the short-wave digging
southeastward into the central Plains. The response appears to be a
southward shift in the mid level frontogenesis and warm advection
supporting this northern band, and increasing large scale ascent
with a vort max head of trof and the backbuilding ULJ. Thus after
06z the primary forcing and ascent shifts southward along and south
of I-70. This would suggest that the northern snow band will fade
while a new and much larger swath of snow spreads/develops across
the southern half of MO/IL. This will place the I-70 corridor on the
northern part of the snow shield and could play havoc with amounts
along the I-70 corridor where the greatest uncertainty in the
forecast resides. Large scale ascent with the migrating short wave
trof and mid level frontogenesis will keep the heart of the snow band
focused south of I-70 across southern MO and southern IL on Sunday
morning with Columbia-St. Louis-Vandalia IL still on the northern
periphery of the deformation snow shield. By mid-late afternoon the
forcing will exit to the east of the area in association with the
migrating short wave trof, bringing and end to the snowfall.
Despite the very cold temperatures and dry nature of the snow, the
sounding profiles continue to show a shallow dendritic growth zone
with much larger profiles supporting columns and plates within the
lift zone. This suggests snow ratios closer to 13-15:1.
The new forecast is not far from the previous one but is a bit lower
in snow totals along I-70 with 5-7 inches due to the uncertainties
discussed, but still looking at 8+ southeast MO into southern IL.
This forecast will need to be further refined this evening in
anticipation of the northern frontogenetic snow band.
No changes needed to the previously issued winter storm watch and
advisories.
Glass
.LONG TERM: (Tuesday through Next Sunday)
Issued at 255 PM CST Sun Feb 15 2015
A cold front wil move southeastward through our forecast area on
Tuesday as a broad positively tilted upper level trough gradually
deepens over the region. There may be some post fronal light snow
Tuesday and Tuesday night, mainly across central and southeast MO
and southwest IL. A secondary cold front will drop southeastward
through our area late Tuesday night and Wednesday morning. Very
cold air is expected to invade our forecast area behind this second
front as a strong surface ridge bulds southeastward into MO from the
northern Plains. The models drop the -24 degree C 850 mb isotherm
southward to near STL on Wednesday. Temperatures on Wednesday and
Wednesday night should be close to 30 degrees below normal due to
this very cold air mass along with snow cover across most of the
forecast area from the recent winter storm. A warming trend should
begin Thursday night due to rising upper level heights along with
surface winds becoming southerly as the surface ridge shifts east of
our area. There may be some light snow Thursday night and Friday,
mainly across southeast MO and southwest IL, due to low-mid level
warm air advection. There will be a better chance of more
significant precipitation Friday night through Sunday as a cold
front sags southward into the area and a southern stream shortwave
approaches. Precipitation type will be in question along and ahead
of the cold front, but should be all snow by Saturday night or
Sunday as another cold air mass drops southward through our area
behind the front.
GKS
&&
.AVIATION: (For the 00z TAFs through 00z Monday Evening)
Issued at 546 PM CST Sun Feb 15 2015
Band of snow stretching from north of KCOU...north of KSTL...to
around KSLO will continue to increase in coverage this evening
while moving east-southeast. Some showery precipitation south of
the band is being reported as a snow pellets or even some sleet.
IFR conditions with vsbys at or below 1SM are being reported with
the band with mostly VFR vsbys to the north and south of the band.
Another area of snow will develop along and south of the I-70
corridor between 03Z and 09Z tonight which will bring moderate to
heavy snow to these areas as well. Expect IFR conditions to
prevail with visibilities at or below 1SM and ceilings at or below
700 FT. Snow will end from west to east Monday morning into the
early afternoon. As the snow tapers off, expect flight conditions
to improve to MVFR with ceilings most likely hanging between 1000-1900FT.
Specifics for KSTL:
Band of moderate to heavy snow is just north of the STL metro area,
but are seeing increasing radar returns over the past hour in the
vicinity of the terminal. Still think there will be some light
snow or snow grains for the first hour or two and then there the
snow should increase in intensity. Timing on this increasing
intensity is uncertain, but it looks like it should be before 03Z.
Once heavier snow begins, expect IFR vsbys to prevail with
ceilings lowering to IFR as well. Should see snow begin lightening
up overnight with light snow and mvfr conditions continuing into
the late morning or early afternoon. Even after the snow ends, it
looks like ceilings should stay between 1000-1900FT.
Carney
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER STORM WARNING until 6 PM CST Monday FOR Audrain MO-Boone
MO-Callaway MO-Cole MO-Crawford MO-Franklin MO-Gasconade MO-
Iron MO-Jefferson MO-Lincoln MO-Madison MO-Moniteau MO-
Monroe MO-Montgomery MO-Osage MO-Pike MO-Ralls MO-Reynolds
MO-St. Charles MO-St. Francois MO-St. Louis City MO-St.
Louis MO-Ste. Genevieve MO-Warren MO-Washington MO.
WINTER WEATHER ADVISORY until 6 PM CST Monday FOR Marion MO-
Shelby MO.
IL...WINTER STORM WARNING until 6 PM CST Monday FOR Bond IL-Calhoun
IL-Clinton IL-Fayette IL-Greene IL-Jersey IL-Macoupin IL-
Madison IL-Marion IL-Monroe IL-Montgomery IL-Randolph IL-
St. Clair IL-Washington IL.
WINTER WEATHER ADVISORY until 6 PM CST Monday FOR Pike IL.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
353 AM CST MON FEB 16 2015
.DISCUSSION...
COLD FRONT CONTINUES TO MOVE THROUGH NORTH TEXAS THIS MORNING AND
IS CURRENTLY ALONG A LINE FROM NEAR TYLER TO CORSICANA TO KILLEEN.
TEMPERATURES HAVE FALLEN INTO THE 30S BEHIND THE FRONT WITH GUSTY
NORTHWEST WINDS. THE FREEZING LINE IS LOCATED FROM GAINESVILLE TO
MINERAL WELLS TO COMANCHE AND WILL SLOWLY ADVANCE EASTWARD THROUGH
THE EARLY MORNING HOURS. IT SHOULD BE LOCATED ACROSS THE NORTHWEST
PARTS OF THE METROPLEX BY SUNRISE. A LARGE AREA OF PRECIPITATION
IS ONGOING ALONG THE FRONTAL BOUNDARY ITSELF AND THIS IS PRIMARILY
RAIN. THE ONLY EXCEPTION HAS BEEN SOME SLEET OR SMALL HAIL WITH
THE STRONGER CONVECTIVE ELEMENTS BEHIND THE FRONT.
THE LEAD SHORTWAVE IN THE TROUGH OVER THE ROCKIES IS IN THE
PROCESS OF EJECTING EASTWARD ACROSS THE PLAINS THIS MORNING. THIS
WILL ALLOW THE COLD FRONT TO CONTINUE RACING SOUTHWARD
TODAY...TAKING THE PRECIPITATION WITH IT. MOST OF THE
PRECIPITATION WILL BE OUT OF THE AREA BY THE AFTERNOON HOURS. OUR
MAIN CONCERN IN THE IMMEDIATE SHORT TERM IS THE POTENTIAL FOR SOME
FREEZING DRIZZLE ACROSS THE NORTHWEST COUNTIES. LATEST HIGH
RESOLUTION GUIDANCE INDICATES AN AREA OF ISENTROPIC ASCENT IN THE
700-500MB LAYER THROUGH EARLY MORNING. THIS IS ASSOCIATED WITH THE
SHORTWAVE TROUGH MOVING THROUGH THE SOUTHERN PLAINS AND THE LIFT
ITSELF WILL LIKELY ONLY PERSIST FOR A FEW HOURS. RUC SOUNDINGS
ACROSS THE WESTERN COUNTIES SHOW SATURATED CONDITIONS DURING THIS
TIME ALTHOUGH DRYING WILL BEGIN TO OCCUR QUICKLY AFTER 12Z. WITH
WEAK ASCENT THROUGH A SATURATED LAYER...AREAS OF DRIZZLE ARE
LIKELY TO OCCUR. TEMPERATURES ARE ALREADY A FEW DEGREES COOLER
THAN PREVIOUSLY ANTICIPATED AND ARE LIKELY TO REMAIN 28 TO 30
DEGREES THROUGH 14Z ACROSS THE NORTHWEST PART OF THE CWA. THIS
SHOULD BE SUFFICIENT FOR SOME LIGHT ICING TO OCCUR MAINLY ON
BRIDGES OVER THE NEXT SEVERAL HOURS. WE HAVE ALREADY RECEIVED ONE
REPORT OF MINOR ICING ON BRIDGES IN MONTAGUE COUNTY. WE WENT AHEAD
AND ISSUED A FREEZING RAIN ADVISORY THROUGH MID MORNING MAINLY FOR
THESE MINOR ICE ACCUMULATIONS ON BRIDGES. MAIN ROADS SHOULD
CONTINUE TO BE FINE AS GROUND TEMPERATURES HAVE BEEN VERY WARM AND
ARE LIKELY TO MELT ANY LIGHT PRECIPITATION.
WITH PRECIPITATION COMING TO AN END LATER TODAY...THERE WILL BE
SOME CLEARING TO THE WEST. IT WILL BE A COLD DAY WITH HIGHS IN THE
30S AND 40S AREAWIDE AND GUSTY NORTHWEST WINDS KEEPING WIND CHILLS
IN THE 20S THROUGHOUT THE DAY. THE MAIN TROUGH OVER THE ROCKIES
WILL ACTUALLY CROSS THE AREA LATE TONIGHT INTO TUESDAY MORNING.
SKIES ARE EXPECTED TO BECOME CLOUDY AGAIN TONIGHT AND FORCING FROM
THIS TROUGH WILL ACTUALLY BE STRONGER...HOWEVER SIGNIFICANT DRYING
WILL HAVE ALREADY OCCURRED BELOW 700MB. IT WILL BE TOUGH TO GET ANY
ADDITIONAL PRECIPITATION LATE TONIGHT INTO EARLY TUESDAY BUT GIVEN
THE STRONG ASCENT WE WILL KEEP SOME 20 POPS FOR LIGHT SNOW MAINLY
ACROSS THE WESTERN COUNTIES. FLURRIES WILL BE POSSIBLE FARTHER TO
THE EAST INTO EARLY TUESDAY MORNING. NO SNOW ACCUMULATIONS ARE
EXPECTED.
TEMPERATURES ARE EXPECTED TO WARM THROUGH THE END OF THE WEEK WITH
HIGHS AGAIN NEAR 70 BY FRIDAY. ANOTHER STRONG SHORTWAVE WILL MOVE
INTO THE WESTERN U.S. BY THIS TIME AND LOW LEVEL MOISTURE WILL
BEGIN TO BE PULLED NORTHWARD IN RESPONSE. ANOTHER STRONG COLD
FRONT IS EXPECTED TO MOVE THROUGH NEXT WEEKEND...MOST LIKELY ON
SATURDAY WITH SCATTERED SHOWERS POSSIBLE LATE FRIDAY INTO EARLY
SUNDAY.
DUNN
&&
.AVIATION...
/ISSUED 154 AM CST MON FEB 16 2015/
WATCHING THE TEMPERATURE TRENDS UNFOLD UPSTREAM AND HAVE DECIDED
THAT THE FREEZING LINE WILL PROBABLY MAKE IT TO AFW BY 13Z/7AM.
RIGHT NOW BELIEVE THAT DFW WILL FALL TO 33 DEGREES BUT OBVIOUSLY
ANOTHER DEGREE DROP IS POSSIBLE AND WITHIN THE RANGE OF ERROR.
THIS IS IMPORTANT BECAUSE A LOW LEVEL TROUGH AXIS WILL MOVE
THROUGH THE METROPLEX AROUND MID-MORNING AND ALL INDICATIONS ARE
THAT THIS SUBTLE LIFT WILL PRODUCE SOME DRIZZLE. HAVE INDICATED A
PERIOD OF FREEZING DRIZZLE AT AFW FROM 13-15Z. THE DRIZZLE AT DFW
SHOULD STAY LIQUID...BUT THE PERIOD OF TIME TO BE CONCERNED ABOUT
IS FROM 13-15Z/7-9AM. ONCE THE TROUGH AXIS MOVES THROUGH THE
DRIZZLE WILL END...AND THERE IS RATHER HIGH CONFIDENCE THAT ANY OF
THIS LIGHT PRECIP WILL SHIFT EAST OF THE METROPLEX TAF SITES BY
15-16Z. THE UNCERTAINTY IS THE EXACT TEMPERATURE THIS MORNING.
HAVE ADDED VCTS TO AFW/FTW TAFS FROM 9Z-11Z FOR CLUSTER OF STORMS
THAT IS MOVING INTO REGION FROM THE WEST. THESE CELLS SHOULD STAY
NORTH AND NORTHWEST OF TAF SITES AND GRADUALLY WEAKEN OVER THE NEXT
FEW HOURS...BUT THEY WILL GET A LITTLE TOO CLOSE FOR COMFORT. WILL
MONITOR AND SEE IF I NEED TO ADD VCTS TO DFW AS WELL.
OTHERWISE IFR CIGS SHOULD PREVAIL THROUGH EARLY MORNING...LIFTING
TO MVFR BY MID-LATE MORNING AS FRONTAL LAYER DEEPENS. CIGS SHOULD
LIFT FURTHER TO VFR BY MID-LATE AFTERNOON.
TR.92
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 40 30 48 34 55 / 40 10 10 5 0
WACO, TX 41 30 48 32 60 / 50 10 10 5 0
PARIS, TX 36 26 46 29 48 / 70 10 10 5 0
DENTON, TX 37 29 48 30 54 / 30 10 10 5 0
MCKINNEY, TX 38 28 48 30 52 / 50 10 10 5 0
DALLAS, TX 41 31 48 35 55 / 50 10 10 5 0
TERRELL, TX 37 29 47 31 54 / 60 10 10 5 0
CORSICANA, TX 40 29 47 33 58 / 70 10 10 5 0
TEMPLE, TX 41 31 48 32 61 / 50 10 10 5 0
MINERAL WELLS, TX 40 29 49 31 58 / 30 20 20 5 0
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
FREEZING RAIN ADVISORY UNTIL 10 AM CST THIS MORNING FOR TXZ091-
092-100>102-115-116-129.
&&
$$
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1142 PM CST Sun Feb 15 2015
.AVIATION...
/06Z TAFS/
MVFR CIGS have moved into KABI. Cold front should be through KSJT
before 06Z, so will start with northeast winds at KSJT, and MVFR
CIGS, although the 1500 foot ceilings may lag behind the front
somewhat. Should arrive at KBBD between now and 07Z/1AM, so have
not started with MVFR CIGS there. The front is moving faster than
earlier anticipated, so have sped up the timing of the arrival of
these low clouds at KSOA and KJCT as well. Expect the MVFR
conditions to prevail through 18Z at most sites, and have
continued the trend to VFR conditions after that time at all
sites. Gusty northeast winds behind the front should persist
through 18Z as well, then diminish slowly through 06Z tomorrow
night, while remaining northeast. 20
&&
.PREV DISCUSSION... /ISSUED 938 PM CST Sun Feb 15 2015/
UPDATE...
The strong cold front has advanced south and at 915 PM extended
from the northern border of Sterling County to the northern border
of Brown county. The latest RUC13 takes this front south to a
Brownwood to Grape Creek line by Midnight, and has the front
reaching the I-10 corridor by 5-6 AM Monday. Temperatures behind
the front have already dropped into the mid 30s in our northern
counties. The showers have moved east of our counties, while
freezing drizzle has developed farther north in southwestern
Oklahoma, where temperatures have dropped below freezing. We could
have some light rain or drizzle, changing to light freezing rain
or drizzle overnight across the Big Country and roughly the
northern third of our area, where temperatures drop to or below
freezing. However, confidence is low that this will be persistent
or widespread enough to cause travel problems. Having mentioned
this, cannot rule out possibility of a little ice on elevated
surfaces and a few slick spots may develop on a few bridges and
overpasses. The latest NAM and RUC moisten the boundary layer
tonight, but are short of saturation across the area of concern
in our northern counties.
With the above considerations, not planning to issue a Winter Weather
Advisory for our northern counties at this time. However, we will
monitor the situation closely and may need to add an advisory if
conditions or expectations change. For now, will update the
forecast to reflect a little faster timing with the front, and to
adjust temperatures and winds accordingly.
19
PREV DISCUSSION... /ISSUED 722 PM CST Sun Feb 15 2015/
UPDATE...
Strong cold front has advanced south into our northern counties
and was just north of Sweetwater and Abilene at 715 PM. This
front is making a little faster progress than previously
expected, and the RUC model appears to have the best handle
on the southward progression of this front tonight. Temperatures
behind the front have already dropped into the upper 30s to lower
40s. Rain showers are occurring across the area north of I-20 and
east of an Aspermont to Abilene line. This is where we have the
highest PoPs tonight. Will have a possibility of light rain or
freezing rain across our northern counties by late tonight, as
surface temperatures drop to or just below the freezing mark.
Forecast has been updated for tonight mainly for winds based on
the RUC, and have adjusted temperatures, winds and dewpoints to
bring in line with current/recent trends in the northern part of
our area.
19
PREV DISCUSSION... /ISSUED 555 PM CST Sun Feb 15 2015/
AVIATION...
/00Z TAFS/
A strong cold front continues to move south into the area this
evening. The front is expected to make it to KABI by 02Z/8PM or
03Z/9PM this evening. Behind it, CIGS are expected to quickly
deteriorate into the MVFR category to around 1500 feet. In
addition, at the KABI terminal, -SHRA or -DZ is expected to
develop after 05Z/11PM tonight, continuing intermittently through
most of the overnight hours. Expect the precipitation to end by
early tomorrow morning, leaving MVFR CIGS behind through most of
the morning before they start to lift for the afternoon hours
tomorrow. Similar conditions expected farther south, minus the
precipitation. The front should be through KSJT and KBBD by
09Z/3AM or 10Z/4AM tonight, possibly a little earlier, and will
check the timing of the front with the next TAF forecast issuance
if the front speeds up. KSOA and KJCT can expect the front an hour
or two later. While there may be some isolated precipitation at
the southern 4 sites, do not think there will be enough to mention
in the TAFs at this time. CIGS should lift at the other sites by
18Z/12PM tomorrow as well. 20
PREV DISCUSSION... /ISSUED 251 PM CST Sun Feb 15 2015/
SHORT TERM...
(Tonight and Tomorrow)
An upper low over the central Baja Peninsula early this afternoon
will weaken as it moves to the east and is sheared into the
southwestern flow aloft of a broad upper trough positioned over
the central CONUS. A cold front associated with the large upper
trough was moving south through the northern Panhandle early this
afternoon and will enter the Big Country late this evening. By
midnight the front should be along the Interstate 20 corridor.
Temperatures for tonight will be slow to drop with temperatures
just reaching the freezing mark over the Big Country around
sunrise. Temperatures will warm quickly after sunrise over the Big
Country with only a few hours of freezing temperatures expected.
Consequently, any light rain and freezing rain mix over the Big
Country will be short-lived and will at most affect only elevated
surfaces for a few hours.
For the remainder of the forecast area south of the Big Country,
morning lows will range from the mid 30s over the central CWA and
the 40s along the Interstate 10 corridor, with any precipitation
falling being in the liquid state. The cold front will push
completely through the forecast area before noon. Rain chances
will end from north to south during the day tomorrow with
afternoon highs reaching the mid 40s over the Big Country and the
upper 40s to around 50 over the southern CWA.
15
LONG TERM...
(Monday night through Sunday)
The shortwave trough currently located over British Columbia will
dive south over the next 24-36 hours, bringing another chance
for light precipitation to the area Monday night into Tuesday
morning. Lift associated with this system does not appear all that
favorable for a significant precipitation event. However, with
additional mesoscale forcing, there should be enough ascent to
generate light precipitation across the area, mainly beginning
after midnight. Point soundings indicate cooling aloft, eroding
the warm nose by the onset of precipitation. The question is how
much dry air will need to be moistened in the lowest few
kilometers. The GFS soundings indicate that significant moistening
will need to take place, while the NAM keeps the boundary layer
nearly saturated. The latter seems to represent an observed bias
with the NAM.
Either way, after midnight, light snow (possibly mixed with some
light sleet) will be possible across much of the CWA, with light
rain confined to the northwest Hill Country. This trend is
expected to continue into Tuesday morning, with precipitation
coming to an end by midday. Accumulations are expected to be minor
(at best) with this system. A dusting of snow is possible, mainly
north of a Sterling City to Cross Plains line, with little to no
accumulations elsewhere. Temperatures are forecast to drop into
the upper 20s, but limited QPF will zap any potential for heavier
snow.
Skies will clear as we move into Tuesday afternoon/evening. Expect
afternoon temperatures to warm into the upper 40s with winds
becoming light from the west/southwest. These light winds, dry
air, and clear skies will allow temperatures to fall into the
upper 20s and lower 30s by Wednesday morning. These cold
temperatures will be a distant memory by the afternoon, as
temperatures rebound back into the lower 60s across most of West
Central TX. The warming trend will continue on Thursday, with
highs in the mid/upper 60s.
We continue to monitor a pattern change heading into the weekend.
The West Coast ridges persists, but the ridge axis shifts back
to the west as a potent trough digs south along the Great Divide.
The flow aloft becomes briefly quasi-zonal by Friday, backing to
the southwest over the weekend as the aforementioned trough digs
toward the Four Corners. This is setting the stage for another
dump of cold air across the Plains. Just how cold remains in
question, but there is good agreement in the medium range models
that a cold front will move across the area by Sunday.
Ahead of this front, the models are developing light QPF across
central TX in response to warm advection and an open gulf. Broad
isentropic ascent is expected across the region Friday and
Saturday. Low PoPs were maintained for Saturday, but may need to
added for some areas on Friday if the latest trends hold. The 12z
ECMWF is much more aggressive with the weekend cold front compared
to the GFS/DGEX, but all of these models develop some QPF across
the area at some point with this system. We`ll continue to monitor
this system as the models zero in on a favored solution.
Johnson
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 75 32 42 27 49 / 40 50 20 30 20
San Angelo 75 36 48 28 50 / 20 20 20 20 20
Junction 71 48 48 31 51 / 20 20 20 20 20
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
1059 AM EST MON FEB 16 2015
.SYNOPSIS...
MOISTURE WILL INCREASE SLOWLY ACROSS THE REGION TODAY AHEAD OF
LOW PRESSURE TRACKING EASTWARD IN THE LOWER MISSISSIPPI RIVER
VALLEY. THE LOW WILL BE NEAR THE FORECAST AREA TONIGHT AND OFF
THE COAST TUESDAY. WINTER-TYPE PRECIPITATION WILL OCCUR ACROSS THE
NORTHERN PORTIONS OF SC BECAUSE OF THE COLDER AIR MASS IN PLACE
AHEAD OF THE SYSTEM. WELL BELOW NORMAL TEMPERATURES EXPECTED
THROUGH THE WEEK UNDER THE INFLUENCE OF AN ARCTIC AIR MASS.
&&
.NEAR TERM /THROUGH TONIGHT/...
BROAD UPPER LEVEL TROUGH IN THE MIDWEST WILL SHIFT EAST WITH
RESULTING FLOW INCREASING FROM THE SOUTHWEST ACROSS THE CAROLINAS.
SURFACE HIGH PRESSURE RIDGING INTO THE AREA BEGINNING TO SHIFT TO
THE NORTHEAST AS LOW PRESSURE TRACKING FROM THE LOWER MISSISSIPPI
VALLEY APPROACHES THE REGION. AIR MASS REMAINS QUITE COLD AND DRY
WITH TEMPERATURES IN THE 30S LATE THIS MORNING AND DEW POINTS IN
THE SINGLE DIGITS IN MOST LOCATIONS. MODELS ARE CONTINUING TO
TREND FURTHER NORTH WITH APPROACHING SURFACE LOW PRESSURE. LATEST
MODELS IN GOOD AGREEMENT WITH SURFACE LOW TRACK ACROSS THE
CSRA/CENTRAL MIDLANDS TONIGHT TO OFF THE NORTH CAROLINA COAST
TUESDAY MORNING. LOW LEVEL WARM ADVECTION/ISENTROPIC LIFT WILL
DEVELOP LATER THIS AFTERNOON ACROSS THE REGION AS THE LOW PRESSURE
AREA APPROACHES. IN-SITU WEDGE LIKELY TO SET UP ACROSS THE
NORTHERN MIDLANDS AND PIEDMONT WITH SHALLOW SURFACE BASED COLD
LAYER. TEMPERATURES WILL STRUGGLE TO RISE THROUGH THE 30S IN THOSE
AREAS. AIR MASS INITIALLY DRY...SO PRECIPITATION MAY BE DELAYED
UNTIL EARLY EVENING. HRRR APPEARS TO BE TRACKING WELL WITH CURRENT
RADAR TRENDS AND IS MUCH FASTER WITH THE PRECIP REACHING THE AREA
THAN THE 12Z NAM. THIS AGREES PRETTY WELL WITH TIMING IN CURRENT
FORECAST SO HAVE NOT MADE ANY ADJUSTMENTS. PRECIPITABLE WATER
INCREASES TO NEAR 1.3 INCHES BY 06Z TUESDAY AND ISENTROPIC LIFT IS
STRONG DURING THIS TIME SO BELIEVE PRECIPITATION MAY BE MODERATE
AT TIMES. MODEL SOUNDINGS INDICATE DEEP WARM NOSE ACROSS THE
REGION TONIGHT AS VERY STRONG LOW LEVEL WARM ADVECTION DEVELOPS.
SOUTHWEST 850MB JETMAX GREATER THAN 60KTS. SHALLOW FREEZING LAYER
LIKELY HOWEVER NORTH OF CAE. LARGE TEMPERATURE GRADIENT EXPECTED
WITH FREEZING TEMPS NORTH OF CAE TONIGHT TO POSSIBLY LOW 50S IN
THE CSRA AS WARM ADVECTION INCREASES AND DEEPENS. TEMPERATURES
EXPECTED TO RISE OVERNIGHT IN THE SOUTHERN AREAS.
WITH DEEP WARM NOSE AND SHALLOW FREEZING LAYER...PRECIPITATION
TYPE MOST LIKELY TO BE FREEZING RAIN IN THE NORTH
MIDLANDS...PIEDMONT AND PEE DEE OVERNIGHT. ICING ESTIMATE UP TO
0.20 INCHES IN THE LANCASTER REGION SEEMS APPROPRIATE GIVEN
EXPECTED QPF. FREEZING RAIN ADVISORY REMAINS IN EFFECT. WINTRY
PRECIPITATION ACROSS THE REST OF THE CWA APPEARS UNLIKELY GIVEN
CURRENT LOW TRACK ACROSS THE SOUTH-CENTRAL MIDLANDS/CSRA.
&&
.SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...
BOTH THE NAM AND GFS SHOW THE CENTER OF THE LOW ALONG THE VA/NC
COAST BY 12Z TUESDAY MORNING WITH MOISTURE DECREASING ACROSS THE
AREA AS THE LOW CONTINUES TO SHIFT FURTHER NORTHEAST THROUGH THE
DAY ON TUESDAY. SHORTWAVE ENERGY ASSOCIATED WITH THE TROUGH WILL
PROMOTE A SLIGHT CHANCE OF LIGHT PRECIP TUESDAY MORNING AS IT
CROSSES THE REGION. MODEL SOUNDINGS SUGGEST MOISTURE BECOMING
QUITE SHALLOW EARLY TUESDAY...KEPT LOW CHANCE POPS AND
PRECIPITATION MAINLY LIQUID RAIN ALTHOUGH LIGHT FREEZING
RAIN/DRIZZLE POSSIBLE IN THE NORTH MIDLANDS THROUGH ABOUT 15Z.
DRYING WILL OCCUR BY TUESDAY AFTERNOON. HIGHS ON TUESDAY ARE
FORECAST NEAR 40 NORTH TO THE LOW 50S SOUTH. DECREASING CLOUDS
TUESDAY NIGHT WILL PROMOTE LOWS IN THE UPPER 20S NORTH TO LOWER
30S SOUTH.
HIGHLY AMPLIFIED UPPER TROUGH OVER THE EASTERN CONUS WEDNESDAY
SUPPORTS BELOW NORMAL TEMPERATURES WITH SOME MID AND HIGH LEVEL
CLOUDS ASSOCIATED WITH SHORT WAVE TROUGHS.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
MODELS ARE IN GOOD AGREEMENT THROUGH FRIDAY NIGHT WITH INCREASING
DIFFERENCES SATURDAY THROUGH MONDAY. HIGHLY AMPLIFIED UPPER LEVEL
PATTERN THROUGH THE LONG TERM WILL KEEP AN UPPER LEVEL RIDGE OVER
THE WEST COAST WITH A TROUGH OVER THE EASTERN US. THIS WILL KEEP
AN ACTIVE PATTERN ACROSS THE FORECAST AREA WITH SYSTEMS EVERY
COUPLE OF DAYS. HIGH PRESSURE ALONG WITH COOLER AND DRIER AIR WILL
BUILD INTO THE REGION WEDNESDAY NIGHT WITH THE UPPER LEVEL TROUGH
AXIS JUST WEST OF THE REGION. THE HIGH WILL BE CENTERED JUST NORTH
OF THE REGION ON THURSDAY THEN EJECT NORTHEASTWARD ON FRIDAY AS
THE NEXT LOW PRESSURE SYSTEM MOVES INTO THE GREAT LAKES REGION
WITH A SECONDARY LOW EXPECTED TO DEVELOP IN CENTRAL TX. MODELS
DIFFER ON THE HANDLING OF THE TX LOW...HOWEVER AGREE ON A FRONTAL
BOUNDARY ACROSS THE FORECAST AREA FOR FRIDAY NIGHT THROUGH MONDAY.
HAVE TRENDED MUCH OF THE LONG TERM TOWARD THE GFS AS RUN TO RUN
CONSISTENCY HAS BEEN BETTER THEN THE ECMWF WHICH HAS MADE
SIGNIFICANT RUN TO RUN CHANGES REGARDING THE TX LOW. TEMPERATURES
THROUGH THE LONG TERM WILL BE SLIGHTLY TO WELL BELOW NORMAL.
&&
.AVIATION /15Z MONDAY THROUGH FRIDAY/...
VFR CONDITIONS THROUGH LATE AFTERNOON THEN MVFR/IFR CONDITIONS FOR
THE REMAINDER OF THE PERIOD.
LOW PRESSURE OVER EASTERN TX WILL MOVE THROUGH THE GULF STATES
TODAY AND INTO THE TAF SITES TONIGHT. CLOUDS WILL CONTINUE TO
LOWER AND THICKEN THROUGH MID AFTERNOON AS WAST TO SOUTHEASTERLY
WINDS PUSH MOISTURE INTO THE AREA. SCATTERED SHOWERS AND MVFR
CIGS WILL MOVE INTO THE AREA AROUND 21Z...HOWEVER EXPECT MORE
WIDESPREAD RAIN WITH MVFR CIGS AND VSBYS TO ENTER THE TAF SITES
AROUND 17/02Z. IFR CIGS WILL MOVE INTO THE TAF SITES LATE IN THE
PERIOD AS THE COLD FRONT CROSSES THE AREA WITH WINDS QUICKLY
VEERING TO WESTERLY AT THE END OF THE PERIOD. FREEZING RAIN IS
NOT EXPECTED AT THE TAF SITES.
EXTENDED AVIATION OUTLOOK...MVFR...POSSIBLE IFR...RESTRICTIONS
COULD LINGER INTO TUESDAY NIGHT. BREEZY CONDITIONS EXPECTED
WEDNESDAY.
&&
.FIRE WEATHER...
A RED FLAG FIRE ALERT ISSUED BY THE SC FORESTRY COMMISSION
REMAINS IN EFFECT.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...FREEZING RAIN ADVISORY FROM 3 PM THIS AFTERNOON TO 7 AM EST
TUESDAY FOR SCZ015-016-020>022.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
805 AM CST MON FEB 16 2015
.SHORT TERM...
329 AM CST
THROUGH THURSDAY...
TEMPERATURES AND WIND CHILLS WILL BE THE PRIMARY FORECAST
CONCERN...ESPECIALLY BY MID TO LATE WEEK AS A POTENTIALLY RECORD
BREAKING ARCTIC AIR MASS TAKES HOLD OF THE AREA FOR A COUPLE OF DAYS.
TEMPERATURES TODAY SHOULD WARM A FEW DEGREES WARMER THAN THOSE
OBSERVED ON SUNDAY. OVERALL...THIS SHOULD PUT HIGHS IN THE UPPER
TEENS TO THE LOW 20S ACROSS THE REGION. A SIGNIFICANT WINTER
STORM...WHICH IS CURRENTLY IMPACTING AREAS FROM CENTRAL ILLINOIS
SOUTHWARD...WILL CONTINUE TO SPREAD ACCUMULATING SNOW ACROSS THIS
REGION TODAY. FOR NORTHERN ILLINOIS AND NORTHWESTERN INDIANA...ALL
WE SHOULD HAVE TO DEAL WITH IS SOME HIGHER LEVEL CLOUDINESS DURING
THE DAY TODAY.
AS STATED IN THE PREVIOUS DISCUSSION...A SIGNIFICANT PIECE OF THE
POLAR VORTEX WILL BE DISLODGED AND FORCED SOUTHWARD OVER THE GREAT
LAKES REGION BY MID WEEK. THIS SHOULD ALLOW A TRUE ARCTIC AIR MASS
FEATURING -20 TO -24 DEGREE CELSIUS 925 MB TEMPERATURES TO SHIFT OUT
OF THE NORTHWEST TERRITORIES OF CANADA RIGHT ACROSS THE CENTRAL
PORTION OF THE COUNTRY. GUIDANCE CONTINUES IN GOOD AGREEMENT WITH THE
HEAT OF THIS AIR MASS MOVING OVER NORTHERN ILLINOIS/NORTHWESTERN
INDIANA ON THURSDAY. THIS TYPE OF AIR MASS IS CAPABLE OF PRODUCING
HIGH TEMPERATURES IN SINGLE DIGITS ABOVE ZERO AREA-WIDE...AND IF
THIS MATERIALIZES COULD RESULT IN RECORD COLD MAX TEMPERATURES FOR
THE DATE ON THURSDAY. SEE CLIMO SECTION BELOW FOR TEMPERATURE
RECORDS FOR CHICAGO AND ROCKFORD.
UNFORTUNATELY...WITH THESE BITTERLY COLD TEMPERATURES WE HAVE TO
TALK ABOUT WIND CHILLS AGAIN. WITH THE LIKELIHOOD OF A 10 TO 15 KT
SUSTAINED NORTHWESTERLY WIND FOR MUCH OF THE PERIOD INTO
THURSDAY...WIND CHILLS WILL LIKELY REACH ADVISORY LEVEL CRITERIA OF
-20 TO -30...ESPECIALLY WEDNESDAY NIGHT INTO THURSDAY. THIS WOULD BE
THE MOST LIKELY PERIOD OF WIND CHILLS FALLING BELOW -20.
HOWEVER...TUESDAY NIGHT AND THURSDAY NIGHT WILL NOT FAVOR MUCH
BETTER...AND COULD BE CLOSE IN MY NORTHERN AREAS FOR NEEDING A
HEADLINE. EITHER WAY YOU LOOK AT IT...IT WILL BE VERY COLD.
ALTHOUGH NO BIG SNOW EVENTS ARE EXPECTED OVER THE NEXT FEW
DAYS...THERE WILL LIKELY BE PERIODS OF FLURRIES AT TIMES TONIGHT
INTO WEDNESDAY AS SEVERAL MINOR MID LEVEL DISTURBANCES IMPACT THE
AREA. HOWEVER...IT APPEARS THE BEST CHANCE FOR SOME BETTER SNOW
SHOWER ACTIVITY..WITH SOME POSSIBLE MINOR ACCUMULATIONS COULD ENTER
THE PICTURE LATE TUESDAY NIGHT INTO WEDNESDAY MORNING. DURING THIS
PERIOD...A SIGNIFICANT PV ANOMALY IS EXPECTED TO SHIFT ACROSS THE
AREA. FORCED LARGE SCALE ASCENT FROM THIS FEATURE...COMBINED WITH
STEEPENING LOW LEVEL LAPSE RATES WITH ARRIVAL OF THE ARCTIC AIR MASS
COULD RESULT IN A FEW SNOW SQUALLS...POTENTIALLY RESULTING IN SOME
MINOR ACCUMULATING SNOWS OVER THE AREA INTO EARLY WEDNESDAY.
THE DEEP ARCTIC AIR MASS WILL ALSO GET LAKE EFFECT SNOWS GOING AGAIN
LATER TONIGHT THROUGH THURSDAY. HOWEVER...IT CONTINUES TO LOOK AS
THOUGH MUCH OF THE FOCUS FOR THIS ACTIVITY WILL REMAIN LARGELY ALONG
THE EASTERN AND SOUTHERN SHORES OF LAKE MICHIGAN. WE WILL CONTINUE
TO MENTION SOME CHANCES FOR THESE SHOWERS ACROSS MAINLY NORTHEASTERN
PORTER COUNTIES IN INDIANA DURING MUCH OF THIS PERIOD...BUT IT EVEN
APPEARS THAT MUCH OF THE ACCUMULATION POTENTIAL WILL REMAIN TO THE
EAST.
KJB
&&
.LONG TERM...
329 AM CST
THURSDAY NIGHT THROUGH SUNDAY...
IF THERE IS ANY GOOD NEWS WITH THIS COLD AIR OUTBREAK...IT WOULD
BE THAT IT LOOKS TO BE FAIRLY PROGRESSIVE. THEREFORE...WARMER
CONDITIONS SHOULD BEGIN TO SET UP ACROSS THE REGION BY FRIDAY AND
INTO NEXT WEEKEND. HOWEVER...THIS WILL BE NO MEANS BE A WARM
SPELL...TEMPERATURES WILL STILL REMAIN BELOW NORMAL THROUGH...AND
BEYOND THE CURRENT FORECAST PERIOD. SOMETIMES THE MODELS DO TRY TO
ERODE THE COLD AIR TOO FAST...SO IT IS POSSIBLE THAT THE WARM UP
COULD BE SLOWER THAN CURRENTLY FORECAST.
THE OTHER CONCERN DURING THE LATER PORTION OF THE PERIOD WILL BE
THE POTENTIAL FOR A MORE ACTIVE PERIOD OF WEATHER...PARTICULARLY
LATE FRIDAY AND INTO THE WEEKEND. MODEL GUIDANCE CONTINUES TO SHOW
CONSIDERABLE DISAGREEMENT FOLLOWING THE PASSAGE OF THE HEART OF
THE MIDWEEK ARCTIC AIR MASS. THEREFORE CONFIDENCE ON SNOWFALL
POTENTIAL ACROSS THE AREA DURING THIS PERIOD REMAINS LOW.
KJB
&&
.CLIMATE...
WHILE THE COLDEST AIR ALOFT ARRIVES WEDNESDAY...THE COLDEST SURFACE
TEMPERATURES MAY RESULT ON THURSDAY FEBRUARY 19TH...WHICH RIGHT NOW
APPEARS COULD JEOPARDIZE SOME RECORDS...ESPECIALLY THE LOW MAXS.
FEB 19TH
RECORD LOW RECORD LOW MAX
CHICAGO -7 (1936) 9 (1936)
ROCKFORD -16 (1979) 7 (1959)
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* SOUTHEAST WINDS TURN SOUTH THEN SOUTHWEST INTO THE
AFTERNOON...WITH VARIABILITY IN DIRECTION. SPEEDS UNDER 10 KT.
* MVFR CIGS POSSIBLE TONIGHT ALONG WITH SOME FLURRIES.
KREIN
//DISCUSSION...UPDATED 12Z...
HIGH PRESSURE IS CENTERED EAST OF THE AREA THIS MORNING WHICH HAS
ALLOWED SOUTHEAST WINDS TO BECOME LIGHT. THE HIGH WILL SHIFT EAST
AND A COLD FRONT WILL DROP SOUTHEAST ACROSS THE AREA TONIGHT.
WINDS WILL TURN SOUTH THEN SOUTHWEST INTO THE AFTERNOON AS THE
HIGH DEPARTS. EXPECT TO SEE SOME VARIABILITY IN WIND DIRECTION
THROUGH THE DAY BUT SPEEDS WILL BE UNDER 10 KT AND PROBABLY AROUND
5 KT FOR MUCH OF THE PERIOD. THE COLD FRONT AND ASSOCIATED UPPER
TROUGH CROSS THE AREA LATER TONIGHT. A PERIOD OF MVFR CIGS MAY
DEVELOP LATE THIS EVENING OR EARLY TONIGHT. IN ADDITION SOME SNOW
FLURRY ACTIVITY WILL PROBABLY DEVELOP BUT HAVE NOT INCLUDED ANY
-SN IN THE TAF GIVEN THAT THE POTENTIAL IS LOW AND NO ACCUMULATION
IS EXPECTED. WINDS WILL TURN NORTHWESTERLY AND MODESTLY INCREASE
IN SPEED TUESDAY MORNING.
MDB
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* HIGH CONFIDENCE IN WIND FORECAST.
* MEDIUM CONFIDENCE IN MVFR CIGS TONIGHT. LOW-MEDIUM CONFIDENCE IN
TIMING.
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...
TUESDAY NIGHT...CHANCE OF SNOW SHOWERS. MVFR CIGS POSSIBLE. WEST-
NORTHWEST WINDS.
WEDNESDAY...CHANCE OF FLURRIES. MVFR CIGS POSSIBLE. BREEZY NORTHWEST
WINDS.
THURSDAY...MAINLY VFR. NORTHWEST WINDS.
FRIDAY...CHANCE OF SNOW ESPECIALLY FRIDAY NIGHT. MVFR/IFR POSSIBLE
LATE. SOUTH WINDS.
SATURDAY...CHANCE OF SNOW ESPECIALLY IN THE MORNING. MVFR
POSSIBLE. SOUTHWEST WINDS BECOMING NORTHWEST.
SUNDAY...MVFR POSSIBLE. NORTH WINDS.
MDB
&&
.MARINE...
220 AM CST
HIGH PRESSURE OVER LAKE HURON AND LAKE ERIE WILL MOVE EASTWARD
TODAY WHILE A COLD FRONT/TROUGH ACROSS THE NORTHERN PLAINS THIS
MORNING TRACKS SOUTHEAST. THE FRONT WILL CROSS LAKE MICHIGAN
TONIGHT SHIFTING SOUTHERLY WINDS TO THE NORTHWEST. A WEAK LOW WILL
THEN DROP ACROSS THE LAKE TUESDAY NIGHT BRINGING A BETTER PUSH OF
COLD AIR WITH A STRONG HIGH BUILDING INTO THE PLAINS BEHIND IT.
NORTHWEST WINDS WILL INTENSIFY WEDNESDAY WITH LOW END GALES STILL
LOOKING LIKE A GOOD POSSIBILITY FOR MOST OF WEDNESDAY AND
WEDNESDAY NIGHT ACROSS CENTRAL AND SOUTHERN PORTIONS OF THE LAKE.
WINDS WILL VERY SLOWLY EASE THURSDAY WITH THE PRESSURE GRADIENT
BEING SLOW TO WEAKEN BETWEEN LOW PRESSURE TO THE EAST AND THE
APPROACHING HIGH FROM THE WEST. THE HIGH SHOULD PUSH OVERHEAD
EARLY FRIDAY BRINGING MUCH LIGHTER WINDS BUT THIS WILL BE SHORT
LIVED AS ANOTHER LOW LOOKS TO AFFECT THE REGION EARLY NEXT
WEEKEND. MODEL GUIDANCE IS AT ODDS NEXT WEEKEND SO DO NOT HAVE
MUCH CONFIDENCE IN ANY DETAILS THIS FAR OUT.
WEB CAMS AND SATELLITE IMAGERY SHOW THE ICE FIELD TO BE PRETTY
EXTENSIVE AROUND THE PERIMETER OF THE LAKE SO HAVE REMOVED WAVES
FROM THE NEARSHORE WATERS.
MDB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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[top]
Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
600 AM CST Mon Feb 16 2015
.SHORT TERM...(Today)
ISSUED AT 332 AM CST MON FEB 16 2015
Winter storm continues relatively on track with previous forecast.
Will not make any timing or coverage changes to the Winter Storm
headlines with the morning update. Counties can be cleared from the
headlines early if needed as the snowfall diminishes from NW to SE
this afternoon.
The 5" snowfall report from Edgewood at 150 am in SW Effingham
county lends confidence that the southeast 6 counties in the Winter
Storm Warning will reach into the 6 to 8" range before the end of
this event. Isolated spots may even climb above 8". Radar trends of
the bands of moderate snows are correlating closely to the RAP and
NAM depiction of 700mb Fn frontogenetic convergence. Projecting
forward through the day, our southeast counties will remain under
waves of Fn convergence and steady snows into the afternoon. Along
I-72, snows will be lighter, but the southern portions of the
advisory counties look on track to climb up to 3" before the
snowfall diminishes on the northern periphery. Have continued with
categorical PoPs in the winter storm warning and advisory areas this
morning, with slight chances up to Lincoln to Paris. PoPs were
trended downward each hour this afternoon to correlate with the
eastward translation of mid level forcing and deep moisture.
Additional accumulations today could reach between 2 to 4" in the
Warning counties S of I-70, with 1 to 2 inches for the southern
portions of the advisory counties between I-70 and I-72. Little to
no snowfall is expected north of a line from Rushville to Lincoln to
Champaign.
&&
.LONG TERM...(Tonight through Sunday)
ISSUED AT 332 AM CST MON FEB 16 2015
Have a 20-30% chance of light snow in far southeast IL early this
evening with little additional accumulations then. Best chance of
accumulating snows this evening will be southeast of IL over KY
where as much as 10-16 inches of snow is expected. WNW winds will be
less than 10 mph tonight so limiting the amount of blowing and
drifting snow in southeast IL. Lows tonight of 8-13F with coldest
readings over deeper fresh snow cover in southeast IL. A cold front
to move se across central/se IL Tue morning and generally move
through dry with limited moisture. Have chance of flurries ne
counties overnight into Tue while better chances of light snow
further ne closer to MI/Lake MI. Highs Tue in lower 20s se of IL
river and upper teens nw of the IL river.
00Z forecast models continue to dig a strong upper level trof
southward into the Midwest including IL Tue night and Wed with
another surge of arctic air into the region. Scattered flurries with
mostly cloudy skies to accompany this trof along with bitter cold
temperatures. Lows Tue night around 5F. Highs Wed only in lower
teens eastern/se IL and 5-10F from I-55 west. Brisk nw winds Wed
with gusts 20-30 mph to give wind chills of 10-15 below zero
northern counties. Even colder Wed night with lows in the single
digits below zero and wind chills of 15-25 below zero. Wind chill
advisory may be needed wed night into thu morning even for central
and southeast IL. Strong upper level trof starts to shift east of IL
Thu but still very cold Thu with arctic high pressure moving into MS
river valley. Highs Thu of 8-13F and coldest from I-74 ne.
As high pressure drifts east of IL late this week and upper level
heights and 850 mb temps elevate, temps to moderate to mildest
readings on Sat in low to mid 30s for highs. But still below normal
for late Feb. Continued to stay close to guidance chances of light
snow this weekend starting Friday night. Big differences with
extended models this weekend with ECMWF showing strong low pressure
moving ne into IL Sat night while GFS keeps precipitation south of
central IL this weekend. GEM model through Sat is looking drier like
the GFS model. The Climate Prediction Center (CPC) 8-14 day
temperature outlook for Feb 23-Mar 1 has IL in greater than 70%
chance of below normal temperatures.
&&
.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
ISSUED AT 600 AM CST MON FEB 16 2015
VFR conditions are expected across the I-74 TAF sites while MVFR
cigs in snow can be expected at times at SPI and DEC this morning.
Cigs could dip down to 2000 feet in some of the steadier snows at SPI,
with periods of 3500 feet where there are breaks in the precip. The
snow should begin to shift southeast of SPI and DEC between 14 and
16z this morning, but MVFR cigs could linger into afternoon. Surface
winds will continue to be relatively light through the period with a
east to northeast wind this morning at 6 to 9 kts. Winds will
back more into a northerly direction this afternoon, then become
SW later tonight ahead of a shortwave. Some MVFR cigs are
projected to affect the I-74 TAF sites after 06z, with a few
flurries possible.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY until 6 PM CST this evening FOR
ILZ049>052-061>063.
WINTER STORM WARNING until 6 PM CST this evening FOR ILZ066>068-
071>073.
&&
$$
SHORT TERM...Shimon
LONG TERM...07
AVIATION...Shimon
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
546 AM CST MON FEB 16 2015
.SHORT TERM...
329 AM CST
THROUGH THURSDAY...
TEMPERATURES AND WIND CHILLS WILL BE THE PRIMARY FORECAST
CONCERN...ESPECIALLY BY MID TO LATE WEEK AS A POTENTIALLY RECORD
BREAKING ARCTIC AIR MASS TAKES HOLD OF THE AREA FOR A COUPLE OF DAYS.
TEMPERATURES TODAY SHOULD WARM A FEW DEGREES WARMER THAN THOSE
OBSERVED ON SUNDAY. OVERALL...THIS SHOULD PUT HIGHS IN THE UPPER
TEENS TO THE LOW 20S ACROSS THE REGION. A SIGNIFICANT WINTER
STORM...WHICH IS CURRENTLY IMPACTING AREAS FROM CENTRAL ILLINOIS
SOUTHWARD...WILL CONTINUE TO SPREAD ACCUMULATING SNOW ACROSS THIS
REGION TODAY. FOR NORTHERN ILLINOIS AND NORTHWESTERN INDIANA...ALL
WE SHOULD HAVE TO DEAL WITH IS SOME HIGHER LEVEL CLOUDINESS DURING
THE DAY TODAY.
AS STATED IN THE PREVIOUS DISCUSSION...A SIGNIFICANT PIECE OF THE
POLAR VORTEX WILL BE DISLODGED AND FORCED SOUTHWARD OVER THE GREAT
LAKES REGION BY MID WEEK. THIS SHOULD ALLOW A TRUE ARCTIC AIR MASS
FEATURING -20 TO -24 DEGREE CELSIUS 925 MB TEMPERATURES TO SHIFT OUT
OF THE NORTHWEST TERRITORIES OF CANADA RIGHT ACROSS THE CENTRAL
PORTION OF THE COUNTRY. GUIDANCE CONTINUES IN GOOD AGREEMENT WITH THE
HEAT OF THIS AIR MASS MOVING OVER NORTHERN ILLINOIS/NORTHWESTERN
INDIANA ON THURSDAY. THIS TYPE OF AIR MASS IS CAPABLE OF PRODUCING
HIGH TEMPERATURES IN SINGLE DIGITS ABOVE ZERO AREA-WIDE...AND IF
THIS MATERIALIZES COULD RESULT IN RECORD COLD MAX TEMPERATURES FOR
THE DATE ON THURSDAY. SEE CLIMO SECTION BELOW FOR TEMPERATURE
RECORDS FOR CHICAGO AND ROCKFORD.
UNFORTUNATELY...WITH THESE BITTERLY COLD TEMPERATURES WE HAVE TO
TALK ABOUT WIND CHILLS AGAIN. WITH THE LIKELIHOOD OF A 10 TO 15 KT
SUSTAINED NORTHWESTERLY WIND FOR MUCH OF THE PERIOD INTO
THURSDAY...WIND CHILLS WILL LIKELY REACH ADVISORY LEVEL CRITERIA OF
-20 TO -30...ESPECIALLY WEDNESDAY NIGHT INTO THURSDAY. THIS WOULD BE
THE MOST LIKELY PERIOD OF WIND CHILLS FALLING BELOW -20.
HOWEVER...TUESDAY NIGHT AND THURSDAY NIGHT WILL NOT FAVOR MUCH
BETTER...AND COULD BE CLOSE IN MY NORTHERN AREAS FOR NEEDING A
HEADLINE. EITHER WAY YOU LOOK AT IT...IT WILL BE VERY COLD.
ALTHOUGH NO BIG SNOW EVENTS ARE EXPECTED OVER THE NEXT FEW
DAYS...THERE WILL LIKELY BE PERIODS OF FLURRIES AT TIMES TONIGHT
INTO WEDNESDAY AS SEVERAL MINOR MID LEVEL DISTURBANCES IMPACT THE
AREA. HOWEVER...IT APPEARS THE BEST CHANCE FOR SOME BETTER SNOW
SHOWER ACTIVITY..WITH SOME POSSIBLE MINOR ACCUMULATIONS COULD ENTER
THE PICTURE LATE TUESDAY NIGHT INTO WEDNESDAY MORNING. DURING THIS
PERIOD...A SIGNIFICANT PV ANOMALY IS EXPECTED TO SHIFT ACROSS THE
AREA. FORCED LARGE SCALE ASCENT FROM THIS FEATURE...COMBINED WITH
STEEPENING LOW LEVEL LAPSE RATES WITH ARRIVAL OF THE ARCTIC AIR MASS
COULD RESULT IN A FEW SNOW SQUALLS...POTENTIALLY RESULTING IN SOME
MINOR ACCUMULATING SNOWS OVER THE AREA INTO EARLY WEDNESDAY.
THE DEEP ARCTIC AIR MASS WILL ALSO GET LAKE EFFECT SNOWS GOING AGAIN
LATER TONIGHT THROUGH THURSDAY. HOWEVER...IT CONTINUES TO LOOK AS
THOUGH MUCH OF THE FOCUS FOR THIS ACTIVITY WILL REMAIN LARGELY ALONG
THE EASTERN AND SOUTHERN SHORES OF LAKE MICHIGAN. WE WILL CONTINUE
TO MENTION SOME CHANCES FOR THESE SHOWERS ACROSS MAINLY NORTHEASTERN
PORTER COUNTIES IN INDIANA DURING MUCH OF THIS PERIOD...BUT IT EVEN
APPEARS THAT MUCH OF THE ACCUMULATION POTENTIAL WILL REMAIN TO THE
EAST.
KJB
&&
.LONG TERM...
329 AM CST
THURSDAY NIGHT THROUGH SUNDAY...
IF THERE IS ANY GOOD NEWS WITH THIS COLD AIR OUTBREAK...IT WOULD
BE THAT IT LOOKS TO BE FAIRLY PROGRESSIVE. THEREFORE...WARMER
CONDITIONS SHOULD BEGIN TO SET UP ACROSS THE REGION BY FRIDAY AND
INTO NEXT WEEKEND. HOWEVER...THIS WILL BE NO MEANS BE A WARM
SPELL...TEMPERATURES WILL STILL REMAIN BELOW NORMAL THROUGH...AND
BEYOND THE CURRENT FORECAST PERIOD. SOMETIMES THE MODELS DO TRY TO
ERODE THE COLD AIR TOO FAST...SO IT IS POSSIBLE THAT THE WARM UP
COULD BE SLOWER THAN CURRENTLY FORECAST.
THE OTHER CONCERN DURING THE LATER PORTION OF THE PERIOD WILL BE
THE POTENTIAL FOR A MORE ACTIVE PERIOD OF WEATHER...PARTICULARLY
LATE FRIDAY AND INTO THE WEEKEND. MODEL GUIDANCE CONTINUES TO SHOW
CONSIDERABLE DISAGREEMENT FOLLOWING THE PASSAGE OF THE HEART OF
THE MIDWEEK ARCTIC AIR MASS. THEREFORE CONFIDENCE ON SNOWFALL
POTENTIAL ACROSS THE AREA DURING THIS PERIOD REMAINS LOW.
KJB
&&
.CLIMATE...
WHILE THE COLDEST AIR ALOFT ARRIVES WEDNESDAY...THE COLDEST SURFACE
TEMPERATURES MAY RESULT ON THURSDAY FEBRUARY 19TH...WHICH RIGHT NOW
APPEARS COULD JEOPARDIZE SOME RECORDS...ESPECIALLY THE LOW MAXS.
FEB 19TH
RECORD LOW RECORD LOW MAX
CHICAGO -7 (1936) 9 (1936)
ROCKFORD -16 (1979) 7 (1959)
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 12Z...
* SOUTHEAST WINDS TURN SOUTH THEN SOUTHWEST INTO THE
AFTERNOON...WITH VARIABILITY IN DIRECTION. SPEEDS UNDER 10 KT.
* MVFR CIGS POSSIBLE TONIGHT ALONG WITH SOME FLURRIES.
MDB
//DISCUSSION...UPDATED 12Z...
HIGH PRESSURE IS CENTERED EAST OF THE AREA THIS MORNING WHICH HAS
ALLOWED SOUTHEAST WINDS TO BECOME LIGHT. THE HIGH WILL SHIFT EAST
AND A COLD FRONT WILL DROP SOUTHEAST ACROSS THE AREA TONIGHT.
WINDS WILL TURN SOUTH THEN SOUTHWEST INTO THE AFTERNOON AS THE
HIGH DEPARTS. EXPECT TO SEE SOME VARIABILITY IN WIND DIRECTION
THROUGH THE DAY BUT SPEEDS WILL BE UNDER 10 KT AND PROBABLY AROUND
5 KT FOR MUCH OF THE PERIOD. THE COLD FRONT AND ASSOCIATED UPPER
TROUGH CROSS THE AREA LATER TONIGHT. A PERIOD OF MVFR CIGS MAY
DEVELOP LATE THIS EVENING OR EARLY TONIGHT. IN ADDITION SOME SNOW
FLURRY ACTIVITY WILL PROBABLY DEVELOP BUT HAVE NOT INCLUDED ANY
-SN IN THE TAF GIVEN THAT THE POTENTIAL IS LOW AND NO ACCUMULATION
IS EXPECTED. WINDS WILL TURN NORTHWESTERLY AND MODESTLY INCREASE
IN SPEED TUESDAY MORNING.
MDB
//ORD AND MDW CONFIDENCE...UPDATED 12Z...
* HIGH CONFIDENCE IN WIND FORECAST.
* MEDIUM CONFIDENCE IN MVFR CIGS TONIGHT. LOW-MEDIUM CONFIDENCE IN
TIMING.
MDB
//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...
TUESDAY NIGHT...CHANCE OF SNOW SHOWERS. MVFR CIGS POSSIBLE. WEST-
NORTHWEST WINDS.
WEDNESDAY...CHANCE OF FLURRIES. MVFR CIGS POSSIBLE. BREEZY NORTHWEST
WINDS.
THURSDAY...MAINLY VFR. NORTHWEST WINDS.
FRIDAY...CHANCE OF SNOW ESPECIALLY FRIDAY NIGHT. MVFR/IFR POSSIBLE
LATE. SOUTH WINDS.
SATURDAY...CHANCE OF SNOW ESPECIALLY IN THE MORNING. MVFR
POSSIBLE. SOUTHWEST WINDS BECOMING NORTHWEST.
SUNDAY...MVFR POSSIBLE. NORTH WINDS.
MDB
&&
.MARINE...
220 AM CST
HIGH PRESSURE OVER LAKE HURON AND LAKE ERIE WILL MOVE EASTWARD
TODAY WHILE A COLD FRONT/TROUGH ACROSS THE NORTHERN PLAINS THIS
MORNING TRACKS SOUTHEAST. THE FRONT WILL CROSS LAKE MICHIGAN
TONIGHT SHIFTING SOUTHERLY WINDS TO THE NORTHWEST. A WEAK LOW WILL
THEN DROP ACROSS THE LAKE TUESDAY NIGHT BRINGING A BETTER PUSH OF
COLD AIR WITH A STRONG HIGH BUILDING INTO THE PLAINS BEHIND IT.
NORTHWEST WINDS WILL INTENSIFY WEDNESDAY WITH LOW END GALES STILL
LOOKING LIKE A GOOD POSSIBILITY FOR MOST OF WEDNESDAY AND
WEDNESDAY NIGHT ACROSS CENTRAL AND SOUTHERN PORTIONS OF THE LAKE.
WINDS WILL VERY SLOWLY EASE THURSDAY WITH THE PRESSURE GRADIENT
BEING SLOW TO WEAKEN BETWEEN LOW PRESSURE TO THE EAST AND THE
APPROACHING HIGH FROM THE WEST. THE HIGH SHOULD PUSH OVERHEAD
EARLY FRIDAY BRINGING MUCH LIGHTER WINDS BUT THIS WILL BE SHORT
LIVED AS ANOTHER LOW LOOKS TO AFFECT THE REGION EARLY NEXT
WEEKEND. MODEL GUIDANCE IS AT ODDS NEXT WEEKEND SO DO NOT HAVE
MUCH CONFIDENCE IN ANY DETAILS THIS FAR OUT.
WEB CAMS AND SATELLITE IMAGERY SHOW THE ICE FIELD TO BE PRETTY
EXTENSIVE AROUND THE PERIMETER OF THE LAKE SO HAVE REMOVED WAVES
FROM THE NEARSHORE WATERS.
MDB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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
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Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
332 AM CST Mon Feb 16 2015
.SHORT TERM...(Today)
ISSUED AT 332 AM CST MON FEB 16 2015
Winter storm continues relatively on track with previous forecast.
Will not make any timing or coverage changes to the Winter Storm
headlines with the morning update. Counties can be cleared from the
headlines early if needed as the snowfall diminishes from NW to SE
this afternoon.
The 5" snowfall report from Edgewood at 150 am in SW Effingham
county lends confidence that the southeast 6 counties in the Winter
Storm Warning will reach into the 6 to 8" range before the end of
this event. Isolated spots may even climb above 8". Radar trends of
the bands of moderate snows are correlating closely to the RAP and
NAM depiction of 700mb Fn frontogenetic convergence. Projecting
forward through the day, our southeast counties will remain under
waves of Fn convergence and steady snows into the afternoon. Along
I-72, snows will be lighter, but the southern portions of the
advisory counties look on track to climb up to 3" before the
snowfall diminishes on the northern periphery. Have continued with
categorical PoPs in the winter storm warning and advisory areas this
morning, with slight chances up to Lincoln to Paris. PoPs were
trended downward each hour this afternoon to correlate with the
eastward translation of mid level forcing and deep moisture.
Additional accumulations today could reach between 2 to 4" in the
Warning counties S of I-70, with 1 to 2 inches for the southern
portions of the advisory counties between I-70 and I-72. Little to
no snowfall is expected north of a line from Rushville to Lincoln to
Champaign.
&&
.LONG TERM...(Tonight through Sunday)
ISSUED AT 332 AM CST MON FEB 16 2015
Have a 20-30% chance of light snow in far southeast IL early this
evening with little additional accumulations then. Best chance of
accumulationing snows this evening will be southeast of IL over KY
where as much as 10-16 inches of snow is expected. WNW winds will be
less than 10 mph tonight so limiting the amount of blowing and
drifting snow in southeast IL. Lows tonight of 8-13F with coldest
readings over deeper fresh snow cover in southeast IL. A cold front
to move se across central/se IL Tue morning and generally move
through dry with limited moisture. Have chance of flurries ne
counties overnight into Tue while better chances of light snow
further ne closer to MI/Lake MI. Highs Tue in lower 20s se of IL
river and upper teens nw of the IL river.
00Z forecast models continue to dig a strong upper level trof
southward into the Midwest including IL Tue night and Wed with
another surge of arctic air into the region. Scattered flurries with
mostly cloudy skies to accompany this trof along with bitter cold
temperatures. Lows Tue night around 5F. Highs Wed only in lower
teens eastern/se IL and 5-10F from I-55 west. Brisk nw winds Wed
with gusts 20-30 mph to give wind chills of 10-15 below zero
northern counties. Even colder Wed night with lows in the single
digits below zero and wind chills of 15-25 below zero. Wind chill
advisory may be needed wed night into thu morning even for central
and southeast IL. Strong upper level trof starts to shift east of IL
Thu but still very cold Thu with arctic high pressure moving into MS
river valley. Highs Thu of 8-13F and coldest from I-74 ne.
As high pressure drifts east of IL late this week and upper level
heights and 850 mb temps elevate, temps to moderate to mildest
readings on Sat in low to mid 30s for highs. But still below normal
for late Feb. Continued to stay close to guidance chances of light
snow this weekend starting Friday night. Big differences with
extended models this weekend with ECMWF showing strong low pressure
moving ne into IL Sat night while GFS keeps precipitation south of
central IL this weekend. GEM model through Sat is looking drier like
the GFS model. The Climate Prediction Center (CPC) 8-14 day
temperature outlook for Feb 23-Mar 1 has IL in greater than 70%
chance of below normal temperatures.
&&
.AVIATION...(For the 06Z TAFS through 06Z Monday night)
ISSUED AT 1100 PM CST SUN FEB 15 2015
VFR conditions are expected across the I-74 TAF sites while MVFR
cigs in snow can be expected at times at SPI and DEC into Monday
morning. Cigs will range from 1200-1500 feet in some of the steadier
snows, to 2500 to 3500 feet where there is a break in the precip.
The snow should begin to shift southeast of SPI and DEC between
12 and 15z Monday morning. Surface winds will continue to be a
non-factor through the period with a east to northeast wind the
remainder of tonight at 8 to 13 kts with winds backing more into
a northerly direction by afternoon.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY until 6 PM CST this evening FOR
ILZ049>052-061>063.
WINTER STORM WARNING until 6 PM CST this evening FOR ILZ066>068-
071>073.
&&
$$
SHORT TERM...Shimon
LONG TERM...07
AVIATION...Smith
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
937 AM EST MON FEB 16 2015
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 224 AM EST MON FEB 16 2015
A VIGOROUS LOW PRESSURE SYSTEM OVER THE SOUTHERN PLAINS IS EXPECTED
TO PUSH ACROSS THE DEEP SOUTH TODAY...SPREADING SNOW ACROSS THE
TENNESSEE AND OHIO VALLEYS...INCLUDING SOUTHERN PARTS OF CENTRAL
INDIANA. ACCUMULATING SNOW IS EXPECTED ACROSS SOUTHERN INDIANA. THE
LOW IS EXPECTED TO REACH THE CAROLINAS TONIGHT...BRINGING AN END TO
SNOWFALL ACROSS THE AREA TONIGHT.
ANOTHER ARCTIC HIGH PRESSURE SYSTEM IS THEN EXPECTED TO BUILD
ACROSS INDIANA IN THE WAKE OF THE LOW. THIS WILL RESULT IN ANOTHER
SHOT OF VERY COLD AIR TO SWEEP INTO INDIANA...PROVIDING DRY
CONDITIONS AND BELOW NORMAL TEMPERATURES. THROUGH THE MIDDLE OF THE
WEEK.
NEXT WEEKEND COULD SEE CHANCES FOR SNOW BUT ALSO A WARMUP AS THE
EAST COAST TROUGH FINALLY ABATES.
&&
.NEAR TERM /TODAY/...
ISSUED AT 224 AM EST MON FEB 16 2015
SURFACE ANALYSIS EARLY THIS MORNING SHOWS ARCTIC HIGH PRESSURE IN
PLACE OVER LOWER MICHIGAN AND A DEVELOPING SURFACE LOW ACROSS
EASTERN TEXAS. A VERY DRY AND COLD EASTERLY SURFACE FLOW WAS IN
PLACE ACROSS CENTRAL INDIANA...AS DEW POINTS WERE BELOW ZERO. THIS
INTRUSION OF DRY LOWER LEVEL AIR WILL BE IMPORTANT IN THIS
FORECAST. SATELLITE SHOWS A WAVE OF CLOUDS OVER MO...IL AND
INDIANA SPREADING EASTWARD. RADAR SHOWS A BAND OF SNOW ACROSS OUR
WARNING AREA IN SOUTHERN CENTRAL INDIANA WHERE SPOTTERS HAVE
REPORTED ABOUT 1/4 INCH OF ACCUMULATION AS OF 100 AM. NOTED ON
RADAR WAS A VERY SHARP CUT OFF SNOW VS NO-SNOW...AND DRY AIR WAS
PLAYING A NOTE. FOR EXAMPLE...DEWPOINTS AT BMG WERE -1. NO SNOW
THERE. DEW POINTS AT VINCENNES...14. SNOWING THERE. A 16 DEGREE
DIFFERENCE. THE VERY COLD TEMPERATURES IN PLACE WILL MAKE FOR
HIGHER SNOW/LIQUID RATIOS...RESULTING IN HIGH SNOW TOTALS IN THE
AREAS THAT GET SNOW.
GFS AND NAM ARE IN PRETTY GOOD AGREEMENT DURING THIS
PERIOD...PUSHING THE SURFACE LOW ACROSS MISSISSIPPI AND
ALABAMA...WHICH IS A MORE FAVORABLE TRACK FOR HEAVIEST SNOWS ACROSS
KENTUCKY. ALOFT A QUICK MOVING SHORT WAVE IS EXPECTED TO PUSH ACROSS
THE OHIO VALLEY THIS AFTERNOON AND EXIT THIS EVENING...EFFECTIVELY
ENDING LIFT THEN. ISENTROPIC SURFACE SHOW LITTLE IN THE WAY OF LIFT
ACROSS CENTRAL INDIANA...WITH BEST ISENTROPIC LIFT MUCH FARTHER
SOUTH. STILL NOTED IN THE 2-3 G/KG SPECIFIC HUMIDITY THAT IS
AVAILABLE ACROSS SOUTHERN PARTS OF CENTRAL INDIANA. Q VECTOR ALSO
SHOW BEST LIFT AND FORCING WELL SOUTH OF CENTRAL INDIANA...ACROSS
TENNESSEE AND KENTUCKY. MEANWHILE TIME HEIGHT SECTIONS SHOW GOOD
LIFT AND SATURATION THROUGH THE MORNING HOURS...WITH BEST MOISTURE
ACROSS THE SOUTHERN PARTS OF THE FORECAST AREA.
FORECAST SOUNDINGS ALSO HINT TOWARD DEEP SATURATION WITH BEST DEEP
MOISTURE IN PLACE ACROSS THE SOUTHERN PARTS OF THE FORECAST AREA
ALONG WITH PRECIPITATABLE WATER AMOUNTS NEAR 0.4 INCHES. ALSO
FAVORABLE FOR SNOW IN THE SOUNDINGS IS THE SATURATION IN THE
DENDRITIC GROWTH ZONE OF -10 TO -20. HRRR SUGGESTS BEST MOISTURE
WILL BE CONTAINED TO THE SOUTHERN PARTS OF THE FORECAST AREA.
FINALLY...NAM ALSO SUGGEST A WEAK TROWAL PUSHING ACROSS SOUTHERN
PARTS OF CENTRAL INDIANA THIS AFTERNOON.
THUS...WILL KEEP THE SNOW AMOUNTS IN PLACE ACROSS THE FAR SOUTHERN
COUNTIES...WITH NEAR 6 INCHES EXPECTED. WITH THE CONTINUE DRY
EASTERLY FLOW...LITTLE TO NO SNOW WILL BE EXPECTED ACROSS THE FAR
NORTHERN PARTS OF THE FORECAST AREA...WITH ONLY 1-2 INCHES OR LESS
ALONG THE I-70 CORRIDOR.
GIVEN ALL OF THIS ONGOING FORECAST HAS A GOOD HANDLE ON
THIS...HOWEVER WILL NOT HESITATE TO UPGRADE THE
SULLIVAN...BLOOMINGTON...AND GREENSBURG AREA TO A WARNING SHOULD
SNOW PILE UP QUICKER THAN EXPECTED. WILL USE 100 POPS SOUTH TO
NEAR 0 NORTH...WITH HIGHS COOLER THAN MAVMOS GIVEN THE COLD
NORTHEASTERLY FLOW.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
ISSUED AT 224 AM EST MON FEB 16 2015
GFS AND NAM ARE IN PRETTY GOOD AGREEMENT WITH THIS PERIOD AND WILL
USE A BLEND MAIN FORECAST CHALLENGE WILL BE TEMPS.
UPPER SHORT WAVE LOOKS TO DEPART THIS EVENING...AND FORCING ENDS
ACROSS THE AREA AS TIME HEIGHTS BEGIN TO SHOW SUBSIDENCE. FAR
ALOFT A FAVORABLE WAVE OF PV MOVES ACROSS CENTRAL
INDIANA...HOWEVER...ALL THE AVAILABLE MOISTURE WILL BE LONG GONE
TO THE EAST BEFORE THIS FEATURE ARRIVES. FORECAST SOUNDINGS
DRY OUT THROUGH THE NIGHT AS COLD AIR ADVECTION IS EXPECTED TO
RESUME IN THE MID LEVELS. BY 12Z TUES...850MB TEMPS FALL TO -13
AND THAT/S NOT ALL. THE COLD AIR ADVECTION WILL CONTINUE INTO
WEDNESDAY...WHEN 850MB TEMPS FALL TO -25C AND RAW NAM NUMERICAL
DATA SPITS OUT A 494 THICKNESS. ALOFT...BROAD CYCLONIC FLOW IS
EXPECTED TO REMAIN IN PLACE ACROSS THE EASTERN PARTS OF CANADA AND
THE UNITED STATES. THIS WILL ALLOW WHAT SEEMS LIKE AN ENDLESS FLOW
OF COLD AIR INTO THE OHIO VALLEY. WE WILL GET NO HELP AT THE
SURFACE AS SURFACE RIDGING LOOKS TO REMAIN WEST OF INDIANA UNTIL
AT LEAST THURSDAY AND BROAD CYCLONIC FLOW LOOKS TO PERSIST.
FURTHERMORE THE FLOW OFF OF LAKE MICHIGAN MAY RESULT IN SOME LAKE
CLOUDS/FLURRIES FROM TIME TO TIME ACROSS THE NORTHEAST PARTS OF
THE FORECAST AREA. THUS WILL TREND HIGHS COLDER THAN
MAVMOS...ESPECIALLY IN THE AREAS THAT RECEIVE NEW SNOW TODAY. WILL
ALSO TREND LOWS COLDER GIVEN THE STRONG COLD AIR ADVECTION.
SO IN SUMMARY...IT/S GONNA BE COLD...IT/S GONNA BE GRAY...AND IT/S
GONNA LAST UNTIL AT LEAST THURSDAY.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
ISSUED AT 243 AM EST MON FEB 16 2015
EXPECT CONTINUED COLD INTO THE LONG TERM PERIOD WITH A BIT OF A WARM
UP LATE IN THE PERIOD AS UPPER LEVEL FLOW BECOMES A BIT MORE ZONAL.
LOW CHANCES FOR PRECIP...MAINLY SNOW...APPEAR MERITED OVER THE
COMING WEEKEND...BUT IN LIGHT OF THE FAIRLY SIGNFICANT MODEL
DIFFERENCES IN HANDLING THIS PERIOD...SEE LITTLE REASON TO ADJUST
BLENDED INITIALIZATION...WHICH HAS THIS HANDLED RELATIVELY WELL.
&&
.AVIATION /DISCUSSION FOR THE 16/15Z IND TAF UPDATE/...
ISSUED AT 937 AM EST MON FEB 16 2015
RADAR AND OBSERVATIONAL TRENDS SUGGESTING FAIRLY STEADY LIGHT SNOW
TODAY WITH IFR CONDITIONS.
PREVIOUS DISCUSSION FOLLOWS...
SNOW HAS OVERSPREAD BMG...HUF AND IND...ALTHOUGH THE NORTHERN EXTENT
OF THE PRECIPITATION SHIELD ENDS WITHIN 10-15 MILES OF HUF/IND...AND
THIS SHOULD ROUGHLY BE THE RULE MUCH OF THE DAY.
EXPECT LIFR CONDITIONS TO DEVELOP AND PERSIST AT BMG...AND IFR
CONDITIONS TO DO THE SAME AT HUF/IND...ALTHOUGH CONDITIONS MAY BE
QUITE VARIABLE AT THESE TWO SITES GIVEN PROXIMITY TO THE EDGE OF THE
PRECIP SHIELD. LAF SHOULD REMAIN VFR AND OUT OF THE PRECIPITATION
THROUGH THE DURATION OF THE EVENT.
WINDS WILL REMAIN EASTERLY AT 10KT OR LESS THROUGH THE
DAY...EVENTUALLY SWINGING NORTHERLY AND WESTERLY AS THE LOW PASSES
TO THE SOUTH...WIND CHANGES WILL BE QUICK ENOUGH TONIGHT TO MERIT A
BLANKET VARIABLE DESIGNATION FOR SAKE OF SIMPLICITY.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL 7 PM EST THIS EVENING FOR INZ067>072.
WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR
INZ060>065.
&&
$$
SYNOPSIS...PUMA
NEAR TERM...PUMA
SHORT TERM...PUMA
LONG TERM...NIELD
AVIATION...NIELD/MK
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
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AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
553 AM EST MON FEB 16 2015
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 224 AM EST MON FEB 16 2015
A VIGOROUS LOW PRESSURE SYSTEM OVER THE SOUTHERN PLAINS IS EXPECTED
TO PUSH ACROSS THE DEEP SOUTH TODAY...SPREADING SNOW ACROSS THE
TENNESSEE AND OHIO VALLEYS...INCLUDING SOUTHERN PARTS OF CENTRAL
INDIANA. ACCUMULATING SNOW IS EXPECTED ACROSS SOUTHERN INDIANA. THE
LOW IS EXPECTED TO REACH THE CAROLINAS TONIGHT...BRINGING AN END TO
SNOWFALL ACROSS THE AREA TONIGHT.
ANOTHER ARCTIC HIGH PRESSURE SYSTEM IS THEN EXPECTED TO BUILD
ACROSS INDIANA IN THE WAKE OF THE LOW. THIS WILL RESULT IN ANOTHER
SHOT OF VERY COLD AIR TO SWEEP INTO INDIANA...PROVIDING DRY
CONDITIONS AND BELOW NORMAL TEMPERATURES. THROUGH THE MIDDLE OF THE
WEEK.
NEXT WEEKEND COULD SEE CHANCES FOR SNOW BUT ALSO A WARMUP AS THE
EAST COAST TROUGH FINALLY ABATES.
&&
.NEAR TERM /TODAY/...
ISSUED AT 224 AM EST MON FEB 16 2015
SURFACE ANALYSIS EARLY THIS MORNING SHOWS ARCTIC HIGH PRESSURE IN
PLACE OVER LOWER MICHIGAN AND A DEVELOPING SURFACE LOW ACROSS
EASTERN TEXAS. A VERY DRY AND COLD EASTERLY SURFACE FLOW WAS IN
PLACE ACROSS CENTRAL INDIANA...AS DEW POINTS WERE BELOW ZERO. THIS
INTRUSION OF DRY LOWER LEVEL AIR WILL BE IMPORTANT IN THIS
FORECAST. SATELLITE SHOWS A WAVE OF CLOUDS OVER MO...IL AND
INDIANA SPREADING EASTWARD. RADAR SHOWS A BAND OF SNOW ACROSS OUR
WARNING AREA IN SOUTHERN CENTRAL INDIANA WHERE SPOTTERS HAVE
REPORTED ABOUT 1/4 INCH OF ACCUMULATION AS OF 100 AM. NOTED ON
RADAR WAS A VERY SHARP CUT OFF SNOW VS NO-SNOW...AND DRY AIR WAS
PLAYING A NOTE. FOR EXAMPLE...DEWPOINTS AT BMG WERE -1. NO SNOW
THERE. DEW POINTS AT VINCENNES...14. SNOWING THERE. A 16 DEGREE
DIFFERENCE. THE VERY COLD TEMPERATURES IN PLACE WILL MAKE FOR
HIGHER SNOW/LIQUID RATIOS...RESULTING IN HIGH SNOW TOTALS IN THE
AREAS THAT GET SNOW.
GFS AND NAM ARE IN PRETTY GOOD AGREEMENT DURING THIS
PERIOD...PUSHING THE SURFACE LOW ACROSS MISSISSIPPI AND
ALABAMA...WHICH IS A MORE FAVORABLE TRACK FOR HEAVIEST SNOWS ACROSS
KENTUCKY. ALOFT A QUICK MOVING SHORT WAVE IS EXPECTED TO PUSH ACROSS
THE OHIO VALLEY THIS AFTERNOON AND EXIT THIS EVENING...EFFECTIVELY
ENDING LIFT THEN. ISENTROPIC SURFACE SHOW LITTLE IN THE WAY OF LIFT
ACROSS CENTRAL INDIANA...WITH BEST ISENTROPIC LIFT MUCH FARTHER
SOUTH. STILL NOTED IN THE 2-3 G/KG SPECIFIC HUMIDITY THAT IS
AVAILABLE ACROSS SOUTHERN PARTS OF CENTRAL INDIANA. Q VECTOR ALSO
SHOW BEST LIFT AND FORCING WELL SOUTH OF CENTRAL INDIANA...ACROSS
TENNESSEE AND KENTUCKY. MEANWHILE TIME HEIGHT SECTIONS SHOW GOOD
LIFT AND SATURATION THROUGH THE MORNING HOURS...WITH BEST MOISTURE
ACROSS THE SOUTHERN PARTS OF THE FORECAST AREA.
FORECAST SOUNDINGS ALSO HINT TOWARD DEEP SATURATION WITH BEST DEEP
MOISTURE IN PLACE ACROSS THE SOUTHERN PARTS OF THE FORECAST AREA
ALONG WITH PRECIPITATABLE WATER AMOUNTS NEAR 0.4 INCHES. ALSO
FAVORABLE FOR SNOW IN THE SOUNDINGS IS THE SATURATION IN THE
DENDRITIC GROWTH ZONE OF -10 TO -20. HRRR SUGGESTS BEST MOISTURE
WILL BE CONTAINED TO THE SOUTHERN PARTS OF THE FORECAST AREA.
FINALLY...NAM ALSO SUGGEST A WEAK TROWAL PUSHING ACROSS SOUTHERN
PARTS OF CENTRAL INDIANA THIS AFTERNOON.
THUS...WILL KEEP THE SNOW AMOUNTS IN PLACE ACROSS THE FAR SOUTHERN
COUNTIES...WITH NEAR 6 INCHES EXPECTED. WITH THE CONTINUE DRY
EASTERLY FLOW...LITTLE TO NO SNOW WILL BE EXPECTED ACROSS THE FAR
NORTHERN PARTS OF THE FORECAST AREA...WITH ONLY 1-2 INCHES OR LESS
ALONG THE I-70 CORRIDOR.
GIVEN ALL OF THIS ONGOING FORECAST HAS A GOOD HANDLE ON
THIS...HOWEVER WILL NOT HESITATE TO UPGRADE THE
SULLIVAN...BLOOMINGTON...AND GREENSBURG AREA TO A WARNING SHOULD
SNOW PILE UP QUICKER THAN EXPECTED. WILL USE 100 POPS SOUTH TO
NEAR 0 NORTH...WITH HIGHS COOLER THAN MAVMOS GIVEN THE COLD
NORTHEASTERLY FLOW.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
ISSUED AT 224 AM EST MON FEB 16 2015
GFS AND NAM ARE IN PRETTY GOOD AGREEMENT WITH THIS PERIOD AND WILL
USE A BLEND MAIN FORECAST CHALLENGE WILL BE TEMPS.
UPPER SHORT WAVE LOOKS TO DEPART THIS EVENING...AND FORCING ENDS
ACROSS THE AREA AS TIME HEIGHTS BEGIN TO SHOW SUBSIDENCE. FAR
ALOFT A FAVORABLE WAVE OF PV MOVES ACROSS CENTRAL
INDIANA...HOWEVER...ALL THE AVAILABLE MOISTURE WILL BE LONG GONE
TO THE EAST BEFORE THIS FEATURE ARRIVES. FORECAST SOUNDINGS
DRY OUT THROUGH THE NIGHT AS COLD AIR ADVECTION IS EXPECTED TO
RESUME IN THE MID LEVELS. BY 12Z TUES...850MB TEMPS FALL TO -13
AND THAT/S NOT ALL. THE COLD AIR ADVECTION WILL CONTINUE INTO
WEDNESDAY...WHEN 850MB TEMPS FALL TO -25C AND RAW NAM NUMERICAL
DATA SPITS OUT A 494 THICKNESS. ALOFT...BROAD CYCLONIC FLOW IS
EXPECTED TO REMAIN IN PLACE ACROSS THE EASTERN PARTS OF CANADA AND
THE UNITED STATES. THIS WILL ALLOW WHAT SEEMS LIKE AN ENDLESS FLOW
OF COLD AIR INTO THE OHIO VALLEY. WE WILL GET NO HELP AT THE
SURFACE AS SURFACE RIDGING LOOKS TO REMAIN WEST OF INDIANA UNTIL
AT LEAST THURSDAY AND BROAD CYCLONIC FLOW LOOKS TO PERSIST.
FURTHERMORE THE FLOW OFF OF LAKE MICHIGAN MAY RESULT IN SOME LAKE
CLOUDS/FLURRIES FROM TIME TO TIME ACROSS THE NORTHEAST PARTS OF
THE FORECAST AREA. THUS WILL TREND HIGHS COLDER THAN
MAVMOS...ESPECIALLY IN THE AREAS THAT RECEIVE NEW SNOW TODAY. WILL
ALSO TREND LOWS COLDER GIVEN THE STRONG COLD AIR ADVECTION.
SO IN SUMMARY...IT/S GONNA BE COLD...IT/S GONNA BE GRAY...AND IT/S
GONNA LAST UNTIL AT LEAST THURSDAY.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
ISSUED AT 243 AM EST MON FEB 16 2015
EXPECT CONTINUED COLD INTO THE LONG TERM PERIOD WITH A BIT OF A WARM
UP LATE IN THE PERIOD AS UPPER LEVEL FLOW BECOMES A BIT MORE ZONAL.
LOW CHANCES FOR PRECIP...MAINLY SNOW...APPEAR MERITED OVER THE
COMING WEEKEND...BUT IN LIGHT OF THE FAIRLY SIGNFICANT MODEL
DIFFERENCES IN HANDLING THIS PERIOD...SEE LITTLE REASON TO ADJUST
BLENDED INITIALIZATION...WHICH HAS THIS HANDLED RELATIVELY WELL.
&&
.AVIATION /DISCUSSION FOR THE 16/12Z TAFS/...
ISSUED AT 553 AM EST MON FEB 16 2015
SNOW HAS OVERSPREAD BMG...HUF AND IND...ALTHOUGH THE NORTHERN EXTENT
OF THE PRECIPITATION SHIELD ENDS WITHIN 10-15 MILES OF HUF/IND...AND
THIS SHOULD ROUGHLY BE THE RULE MUCH OF THE DAY.
EXPECT LIFR CONDITIONS TO DEVELOP AND PERSIST AT BMG...AND IFR
CONDITIONS TO DO THE SAME AT HUF/IND...ALTHOUGH CONDITIONS MAY BE
QUITE VARIABLE AT THESE TWO SITES GIVEN PROXIMITY TO THE EDGE OF THE
PRECIP SHIELD. LAF SHOULD REMAIN VFR AND OUT OF THE PRECIPITATION
THROUGH THE DURATION OF THE EVENT.
WINDS WILL REMAIN EASTERLY AT 10KT OR LESS THROUGH THE
DAY...EVENTUALLY SWINGING NORTHERLY AND WESTERLY AS THE LOW PASSES
TO THE SOUTH...WIND CHANGES WILL BE QUICK ENOUGH TONIGHT TO MERIT A
BLANKET VARIABLE DESIGNATION FOR SAKE OF SIMPLICITY.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL 7 PM EST THIS EVENING FOR INZ067>072.
WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR
INZ060>065.
&&
$$
SYNOPSIS...PUMA
NEAR TERM...PUMA
SHORT TERM...PUMA
LONG TERM...NIELD
AVIATION...NIELD
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AREA FORECAST DISCUSSION
NWS GOODLAND KS
407 AM MST MON FEB 16 2015
.SHORT TERM...(TODAY THROUGH WEDNESDAY NIGHT)
ISSUED AT 404 AM MST MON FEB 16 2015
FORECAST CONCERNS WILL BE HIGH TEMPERATURES THROUGH THE PERIOD...CHANCE
OF PRECIPITATION INTO TUESDAY...AND WINDS ON TUESDAY. SATELLITE SHOWING
AN AMPLIFIED PATTERN FROM THE PACIFIC INTO THE WESTERN ATLANTIC. THIS
PATTERN CONSISTS OF A LARGE AND COMPLEX TROUGH OVER MOST OF THE PACIFIC
TO A HIGHLY AMPLIFIED RIDGE ALONG THE WEST COAST OF NORTH AMERICA THEN
TO A BROAD TROUGH OVER THE EASTERN TWO THIRDS OF THE COUNTRY.
NUMEROUS SHORTWAVE TROUGHS WITHIN THIS FLOW. ONE SHORTWAVE THAT
BROUGHT SNOW TO THE AREA HAS MOVED SOUTH AND EAST. ANOTHER
SHORTWAVE TROUGH IS APPROACHING BEHIND THIS TROUGH. AT JET
LEVEL...MODELS STARTED OUT FINE. AT MID LEVELS...THE CANADIAN...
UKMET AND GFS WERE DOING A LITTLE BETTER THAN THE OTHER OUTPUT.
THE SREF WAS DOING THE BEST SO FAR ON THE SURFACE WIND AND
PRESSURE PATTERN. THE ECMWF...GFS...NAM AND CANADIAN WERE DOING
BEST ON THE LOW LEVEL THERMAL FIELD.
TODAY/TONIGHT...CURRENTLY THERE IS AN AREA OF FOG ENTERING THE
NORTHWEST PORTION OF THE FORECAST AREA. THE SMALL SCALE
GUIDANCE...ESPECIALLY THE HRRR...CATCHES ONTO THIS AND BRINGS AN
AREA OF FOG INTO MOST OF THE WESTERN HALF OF THE AREA THROUGH MID
MORNING. SOME INDICATIONS THAT IT COULD BE DENSE. SO EXPANDED THE
FOG AREA THAT THE EVENING SHIFT PUT INTO THE GRIDS. THIS WILL NEED
TO BE WATCHED CLOSELY.
MAIN JET ENERGY STAYS WELL WEST AND SOUTH OF THE AREA THROUGH THIS
PERIOD. NEW MODEL GUIDANCE HAS TAKEN THE NEXT SHORTWAVE...WHICH
HAS BEEN ADVERTISED FOR A FEW DAYS...FURTHER WEST WHICH HAS ALSO
BEEN THE TREND RECENTLY. BASED ON THE HEIGHT FALLS AND LATEST
RADAR...THIS LOOKS REASONABLE. PRECIPITATION TO THE WEST OF AREA
AT THIS TIME LOOKS TO BRUSH THE FAR WESTERN PORTION OF CHEYENNE
AND KIT CARSON COUNTIES. ONLY MADE MODIFICATIONS TO THE EVENING
SHIFTS DEPICTION OF THIS.
A SECONDARY SHORTWAVE APPROACHES FROM THE NORTH LATE THIS MORNING
AND EARLY THIS AFTERNOON. THETA-E LAPSE RATES AND THE TQ INDEX
WOULD INDICATE THAT THE AIR MASS HAS SOME INSTABILITY AND WILL BE
SUSCEPTIBLE TO THE LIFT THAT WILL BE PRESENT. THIS MATCHES WELL
WITH THE LIGHT QPF GENERATED BY THE MODEL OUTPUT. SO PUT IN SLIGHT
CHANCE TO LOW CHANCE POPS TO CAPTURE THIS. THIS AREA OF PRECIPITATION
ENDS DURING THE EVENING. FAVORABLE THETA-E LAPSE RATES AND WEAK
LIFT REMAIN THROUGH THE NIGHT WITH NOT AS MUCH MOISTURE. SO
INSERTED FLURRIES INTO THE FORECAST AFTER MIDNIGHT.
COMBINATION OF CLOUD COVER AND PRECIPITATION WILL KEEP HIGH TEMPERATURES
ON THE COLD SIDE...BUT WARMER THAN YESTERDAY. SO WENT TOWARD THE COOLER
AND BETTER RECENT PERFORMING GUIDANCE.
TUESDAY/TUESDAY NIGHT...VERY STRONG NORTH TO SOUTH JET MOVES TOWARD
THE AREA DURING THE DAY. MODELS ARE IN MUCH BETTER AGREEMENT AS TO
THIS JETS POSITION THAN THE PREVIOUS FEW DAYS. HOWEVER THE
CANADIAN STILL REMAINS THE FURTHEST WEST. LEFT FRONT QUADRANT OF
THE JET APPROACHES THE WESTERN PORTION OF THE AREA BY LATE
MORNING. THIS JET LEFT FRONT QUADRANT LOOKS TO AFFECT THE ENTIRE
AREA IN THE AFTERNOON.
THETA-E LAPSE RATES AND THE TQ INDEX INDICATE INSTABILITY REMAINS
ALOFT AND THE AIR MASS WILL BE SUSCEPTIBLE TO THE LIFT COMING.
WITH THE STRONG JET AFFECTING THE AREA...PUT IN SLIGHT CHANCE TO
LOW CHANCE POPS TO ACCOUNT FOR THIS.
IT STILL LOOKS LIKE A WINDY DAY. THE QUESTION IS HOW MUCH. LAPSE
RATES THROUGH 700 MB LOOK GOOD WITH LESS FAVORABLE LAPSE RATES
ABOVE THIS. DOWNWARD MOTION IS NOT THAT STRONG PLUS LOOK TO HAVE
CLOUD COVER AS WELL. WILD CARD IN THIS IS THE PRECIPITATION THAT
COULD MIX DOWN THE HIGHER WINDS. MOST MODEL OUTPUT HAS NEAR 40
KNOTS THAT WILL BE MIXED DOWN. HOWEVER...A COUPLE OF THE MODELS
ARE SHOWING WINDS NEAR 50 KNOTS. RIGHT NOW IT LOOKS LIKE WE COULD
GUST TO AROUND 50 MPH. AGAIN THE DAY SHIFT WILL HAVE TO TAKE A
CLOSE LOOK AT THIS.
IT LOOKS LIKE A COLD SURGE MOVES IN EARLY IN THE MORNING. THAT
COMBINED WITH A LOT OF CLOUD COVER THROUGH THE MIDDLE OF THE DAY
WILL MAKE FOR A COLDER DAY. SO TRENDED AGAIN TOWARD THE COOLER AND
RECENT BETTER PERFORMING GUIDANCE IN THIS SCENARIO.
UPPER JET/LEFT FRONT QUADRANT MOVES INTO THE EASTERN PORTION OF
THE AREA BY LATE EVENING AND NEAR THE EASTERN EDGE OR JUST OF THE
AREA BY LATE IN THE NIGHT. RIGHT NOW WILL NOT HAVE MENTION OF ANY
PRECIPITATION BUT WOULD NOT BE SURPRISED THAT SOME FLURRY ACTION
COULD CONTINUE INTO THE EARLY EVENING.
WINDS LOOK LIGHT FOR MOST OF THE NIGHT WITH NOT A LOT OF CLOUD
COVER TO START OUT. MODELS DO INCREASE THE CLOUD COVER IN THE LAST
HALF OF THE NIGHT PROBABLY BECAUSE OF THE JET. THINK WE WILL
PROBABLY DROP QUICKLY BEFORE CLOUD COVER STOPS THE FALL. WENT
COOLER BUT NOT AS COOL AS I COULD HAVE GONE.
WEDNESDAY/WEDNESDAY NIGHT...UPPER JET MOVES EAST OF THE AREA
DURING THE DAY. MODELS DEVELOP A LOT OF MID AND HIGH LEVEL CLOUD
COVER OVER THE AREA INTO THE AFTERNOON. THIS CLOUD COVER HANGS ON
THE LONGEST IN THE EASTERN PORTION OF THE AREA. THERE COULD END UP
BEING QUITE THE GRADIENT. AIR MASS DOES WARM UP. AT THIS TIME WILL
HAVE THE WESTERN PORTION WARMER THAN THE EASTERN PORTION.
.LONG TERM...(THURSDAY THROUGH SUNDAY)
ISSUED AT 315 AM MST MON FEB 16 2015
APOLOGIZE FOR LATENESS ON THIS LONG TERM AFD...MUCH COLLABORATION
AND GRID EDITING WAS NEEDED FROM THE CR INITIALIZATION PROCEDURE.
FORECAST GUIDANCE AND ENSEMBLES HAVE COME INTO MUCH BETTER AGREEMENT
FOR THIS EXTENDED FORECAST RUN. HOWEVER...MAJOR CONCERNS REMAIN...
ESPECIALLY FOR POTENTIAL PRECIPITATION OUTCOMES. OVERALL...COLD
TEMPERATURES ARE ASSURED BUT TIMING AND PLACEMENT OF PRECIPITATION
REMAINS A MAJOR QUESTION MARK.
BEGINNING WITH THURSDAY...WARMEST DAY OF THE PERIOD IS FORECAST.
THIS IS DUE TO BRIEF UPPER LEVEL RIDGING...EMPHASIS ON BRIEF. THIS
ALLOWS SOUTHWEST WINDS ALOFT AND A WARM AIR SURGE EAST FROM THE
COLORADO FRONT RANGE. FRIDAY`S TEMPERATURE FORECAST IS COMPLICATED
AS THERE COULD BE RESIDUAL WARMTH. HOWEVER...A LEE CYCLONE MAY
DEVELOP AND WITH COLD AIR SLIDING SOUTH...CYCLONE MAY AID AN EARLIER
COLD AIR ARRIVAL. MAJOR TEMPERATURE BUST POTENTIAL FRIDAY AS THERE
COULD BE PREFRONTAL MIXING INTO WARMER AIR ALOFT OR THE CYCLONE
PULLING COLD AIR IN FASTER. NOT SURE WHICH SOLUTION WINS SO HAVE
LEFT FRIDAYS TEMPERATURES LARGELY UNTOUCHED. NO PRECIPITATION IS
FORECAST THROUGH FRIDAY.
MAJOR CHANGES ARRIVE FRIDAY NIGHT...LASTING INTO AT LEAST NEXT WEEK.
ACCORDING TO OPERATIONAL RUNS AND ENSEMBLES...LARGE TROUGH OF LOW
PRESSURE DEVELOPS IN NORTHWEST FLOW REGIME...PERSISTING OVER THE
WESTERN UNITED STATES. ADDITIONALLY...LARGE RIDGE OF HIGH PRESSURE
BUILDS OVER THE PACIFIC...EXTENDING NORTH TO CANADA AND ALASKA. THIS
PATTERN IS HIGHLY FAVORABLE FOR ANOTHER ARCTIC OUTBREAK. MODELS ARE
LATCHING ON...INDICATING THE ARCTIC SURFACE HIGH SLIDING SOUTH BY
SATURDAY. LATEST WPC GUIDANCE FORECASTS THE SAME SCENARIO. LARGE
DIFFERENCES REMAIN WITH RESPECT TO SURFACE HIGH STRENGTH AND HOW
COLD WE DROP. GFS BRINGS A 1044 MB HIGH WITH MAX/MIN TEMPS IN THE
30S/TEENS SATURDAY AND 20S/NEAR 10 SUNDAY...WARMING MONDAY. THE
SCARIER SOLUTION IS WHAT ECMWF AND GEFS ENSEMBLE MEAN SUGGEST...A
STRONG ARCTIC HIGH SLIDING SOUTH AND STALLING OVER THE HIGH PLAINS
THROUGH MID-WEEK. ECMWF INDICATES A 1058 MB SURFACE HIGH WHILE THE
GEFS ENSEMBLE MEAN BROADCASTS A 1045+ HIGH. ECMWF AND GEFS ENSEMBLE
MEAN DO NOT ADVANCE THE SURFACE HIGH EAST TO THE GREAT LAKES LIKE
THE OPERATIONAL GFS DOES. AS FOR ECE TEMPERATURES...FORECAST CALLS
FOR MAX/MIN TEMPS SATURDAY IN THE 30S/SINGLE DIGITS AND SUNDAY IN
THE TEENS/NEAR 0. MONDAY WARMS TO THE LOW 20S ACCORDING TO EUROPEAN
GUIDANCE...MUCH COOLER THAN THE OPERATIONAL GFS. NEEDLESS TO SAY...
IT WILL BE QUITE COLD/BELOW NORMAL THIS COMING WEEKEND INTO NEXT
WEEK. THIS PATTERN HAS BEEN DEPICTED BY GUIDANCE FOR SEVERAL RUNS SO
CONFIDENCE IN COLDER TEMPERATURES IS HIGH. LATEST SUPERBLEND LOWERED
TEMPERATURES AND IN COLLABORATION WITH NEIGHBORING OFFICES...FURTHER
DOWNWARD ADJUSTMENTS WERE MADE.
NOW...PRECIPITATION CHANCES. GUIDANCE DISAGREEMENT REMAINS FAIRLY
HIGH WITH RESPECT TO SHORTWAVE TROUGHS/UPPER LEVEL DISTURBANCES FOR
ONE TO FEEL CONFIDENT IN PINPOINTING PRECIP CHANCES. MOST GUIDANCE
INDICATES A STRONG PRECIPITATION SIGNAL FRIDAY NIGHT THROUGH
SATURDAY NIGHT IN ASSOCIATION WITH A STRONG SHORTWAVE MOVING IN.
SUPERBLEND INCREASED POPS TO 40 PERCENT FOR THESE DAYS AND SEE NO
REASON TO DEVIATE. SUNDAY AND BEYOND...AM CONCERNED THAT THE ARCTIC
SURFACE HIGH SLIDING SOUTH COULD CONFINE PRECIPITATION ALONG THE
COLORADO FRONT RANGE WITH COLD BUT DRY CONDITIONS FOR THE HIGH
PLAINS. GLANCING AT SOUNDINGS...VERY COLD TEMPERATURES LEAD TO A
VERY LOW DENDRITIC GROWTH LAYER SO IT WOULD BE EASY FOR PRECIP
DEVELOPMENT IN THAT AIR MASS. FOR NOW...LOWERED POPS DUE TO LOW
CONFIDENCE IN THE EVOLUTION OF ANY PRECIPITATION PRODUCING SYSTEM
BEYOND SATURDAY NIGHT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1000 PM MST SUN FEB 15 2015
KGLD...VFR CONDITIONS EXPECTED THROUGH THE PERIOD. NORTHWEST WINDS
UNDER 10KTS AT TAF ISSUANCE EXPECTED TO CONTINUE THROUGH 19Z
BEFORE INCREASING TO 12KTS FROM 20Z-23Z. AFTER 23Z WINDS SLOWLY
BACK TO THE WEST-SOUTHWEST NEAR 10KTS. CLOUDINESS PRIMARILY MID
AND UPPER LEVELS. WILL HAVE TO WATCH FOR SOME MVFR CLOUDINESS FROM
TAF ISSUANCE THROUGH 15Z PER NAM AND LESSER EXTENT RUC MOISTURE
CROSS-SECTIONS. MODELS ALSO RATHER PERSISTENT IN PRODUCING SOME
FOG/MIST DURING THE SAME TIME PERIOD. WITH KITR RECENTLY DROPPING
TO IFR CIGS WILL BEGIN THE PERIOD WITH A TEMPO GROUP FOR IFR CIGS.
KMCK...VFR CONDITIONS EXPECTED THROUGH THE PERIOD. LIGHT/VARIABLE
WINDS AT TAF ISSUANCE EXPECTED TO BECOME NORTHWEST AROUND 6KTS BY
09Z THEN 13KTS FROM 20Z-22Z BEFORE DECREASING TO 10KTS BY 23Z.
WEST-NORTHWEST WINDS AROUND 7KTS EXPECTED AFTER 05Z. CLOUDINESS
CONFINED TO MID AND UPPER LEVELS THROUGH 19Z BEFORE DECREASING BUT
REMAINING VFR FOR THE REST OF THE TAF PERIOD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...BULLER
LONG TERM...RRH
AVIATION...99
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
500 AM CST MON FEB 16 2015
...UPDATE TO AVIATION...
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 207 AM CST MON FEB 16 2015
A BAND OF STEADIER SNOWFALL EARLIER THIS MORNING RELATED WELL
WITH A 700MB BAROCLINIC ZONE THAT WAS LOCATED AHEAD OF AN UPPER
LEVEL TROUGH WHICH WAS CROSSING EASTERN COLORADO AS OF 06Z. NAM,
HRRR, AND RAP WERE ALL IN DECENT AGREEMENT WITH THIS BAND OF
STEADIER SNOWFALL CROSSING ALL OF SOUTHWEST AND MOST OF SOUTH
CENTRAL KANSAS BY 12Z MONDAY. SOME LIGHTER SNOWFALL IS STILL
EXPECTED EARLY THIS MORNING SOUTH AND EAST OF A DODGE CITY,
HOWEVER EVEN THIS LIGHT PRECIPITATION IS EXPECTED TO BE ENDING BY
15Z. ADDITIONAL SNOWFALL AMOUNTS EARLY THIS MORNING IN THIS AREA
OF LINGERING SNOWFALL IS EXPECTED TO BE LESS THAN ONE HALF OF AN
INCH. LARGE SCALE SUBSIDENCE IS FORECAST BEHIND THIS UPPER LEVEL
TROUGH AS IT MOVES EAST OF THE AREA EARLY THIS MORNING, HOWEVER
BUFR SOUNDINGS AND EVEN THE HRRR HINT AT SOME LINGERING LOW LEVEL
MOISTURE/STATUS DURING EARLY MORNING HOURS. SOME HIGH LEVEL
MOISTURE/CLOUDS WILL THEN BE POSSIBLE DURING THE AFTERNOON.
CONFIDENCE IS NOT HIGH ON HOW MUCH AFTERNOON CLOUD COVER THERE
WILL BE LATER THIS AFTERNOON, HOWEVER GIVEN THE CURRENT CLOUD
COVER EXPECTED TODAY ALONG WITH THE SNOW THAT FELL DURING THE
OVERNIGHT HOURS WILL UNDERCUT THE COOLER MET GUIDANCE BY SEVERAL
DEGREES. THIS WILL BE CLOSE TO THE PREVIOUS FORECAST FOR HIGHS
TODAY WHICH WILL RANGE FROM THE MID 30S TO NEAR 40.
TONIGHT...CLOUDS WILL BE ON THE INCREASE AS ANOTHER UPPER LEVEL
DISTURBANCE BEGINS TO APPROACH CENTRAL HIGH PLAINS FROM THE
NORTHWEST. A SURFACE BOUNDARY WILL MOVE SOUTH/SOUTHWEST ACROSS
NORTH CENTRAL KANSAS OVERNIGHT WITH SOME INCREASING MOISTURE AND
LIFT DEVELOPING NORTH OF THIS BOUNDARY. THIS MAY GIVE RISE TO A
FEW FLURRIES TOWARDS DAYBREAK. AT THIS TIME GIVEN WHERE THIS
SURFACE BOUNDARY IS EXPECTED TO BE LOCATED TOWARDS 12Z TUESDAY
WILL KEEP A MENTION THE SLIGHT CHANCE FOR LIGHT SNOW GOING ACROSS
MAINLY NORTH CENTRAL KANSAS. WITH THE INCREASING CLOUDS TONIGHT
HAVE DECIDED TO STAY CLOSE TO THE LATEST GUIDANCE WITH
TEMPERATURES FALLING BACK TO AROUND 20 DEGREES.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 333 AM CST MON FEB 16 2015
TUESDAY:
INCREASES POPS NEAR HAYS TUESDAY EVENING AS AN 850-700-HPA WEAK PERTURBATION/BAROCLINIC
ZONE MOVES ACROSS AND COULD PROVIDE THE REGION WITH A SHOWERS/SNOW SHOWERS.
STEEPENING LOW LEVEL LAPSE RATES AND OUTPUT FROM THE ARW CORES AND THE
4 KM NAM GIVE SOME CREDENCE TO THIS. ACTIVITY SHOULD BE FAIRLY LIGHT
IN THE DRY NORTHWESTERLY FLOW ALOFT. TEMPERATURES WILL WARM TO AROUND
40-45F OUTSIDE THIS ACTIVITY ACROSS THE CENTRAL AND SOUTHERN ZONES WITH
COOLER 30S NEAR THE I70 CORRIDOR. OVERNIGHT LOWS WILL BE COLD AND IN
THE UPPER TEENS.
WEDNESDAY:
FAIRLY STRONG NNW FLOW ALOFT WILL CONTINUE ALONG WITH HIGH PRESSURE
ACROSS THE CENTRAL AND NORTHERN PLAINS. THERE WILL BE SOME WEAK LEE
TROUGHING BY WEDNESDAY EVENING AND TEMPERATURES SHOULD MODERATE A FEW
DEGREES - PARTICULARLY ACROSS THE SOUTHWEST ZONES TO MAINLY THE 40S.
NO PRECIPITATION IS EXPECTED.
AND THE REST:
ATTENTION THEN TURNS TO THE WEEKEND. SUPERBLEND STILL HAS CHANCE POPS,
WHICH LOOKS REASONABLE NOW AS THE NEXT WAVE MOVES ACROSS THE CENTRAL
PLAINS. BOTH GFS AND ECMWF SHOW THE CHANCE FOR ACCUMULATING SNOWFALL
WITH THIS NEXT SYSTEM. RIGHT NOW IT IS WAY TOO EARLY TO TELL WHERE AND
HOW MUCH SNOWFALL IS POSSIBLE. ONE THING THAT IS MORE CERTAIN IS MUCH
COOLER TEMPERATURES FOLLOWING A WARM UP. COORDINATED WITH GLD AND TWEAKED
TEMPERATURES SOMEWHAT TO AT LEAST TREND COOLER. TEMPS NOW ARE PROBABLY
WAY TOO WARM AND WILL NEED TO BE ADJUSTED IF THE MODELS CONTINUE AS
ROBUST WITH THIS UPCOMING COLD OUTBREAK.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 500 AM CST MON FEB 16 2015
THE SNOW BAND HAS ALREADY MOVED SOUTHEAST OF THE TERMINALS AND CONDITIONS
ARE VFR NOW. EXPECT VFR TO CONTINUE FOR THE REST OF THE TAF PD. WINDS
WILL BE NORTHWESTERLY TO NORTHERLY AT 5 TO 10 KT.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 38 22 41 19 / 50 10 10 0
GCK 38 21 41 18 / 10 10 10 0
EHA 38 23 42 22 / 10 10 10 0
LBL 38 21 43 20 / 20 10 10 0
HYS 39 22 35 17 / 10 20 30 10
P28 37 23 41 19 / 100 10 20 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BURGERT
LONG TERM...SUGDEN
AVIATION...SUGDEN
AREA FORECAST DISCUSSION
NWS GOODLAND KS
316 AM MST MON FEB 16 2015
.UPDATE...
ISSUED AT 1000 PM MST SUN FEB 15 2015
PRECIPITATION QUICKLY COMING TO AN END FROM NORTH TO SOUTH THIS
EVENING AS MUCH DRIER AIR MOVES IN. FORECAST AREA SHOULD BE CLEAR
OF PRECIP A FEW HOURS AFTER MIDNIGHT. PER MODEL BOUNDARY LAYER RH
AND VISIBILITY FORECASTS HAVE ADDED PATCHY FREEZING FOG TO THE
WESTERN 1/2 OF THE AREA.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 211 PM MST SUN FEB 15 2015
MAIN FOCUS IN THE SHORT TERM CONTINUES TO BE ON SNOW POTENTIAL THIS
AFTERNOON THROUGH MONDAY AS SHORTWAVE TROUGH CURRENTLY OVER WESTERN
COLORADO/NORTHERN NEW MEXICO SLOWLY EJECTS ACROSS THE PLAINS.
MOST 12Z GUIDANCE (NAM/GFS) AND LATEST SHORT RANGE GUIDANCE
(RAP/HRRR) SEEM TO HAVE BETTER HANDLE ON LOCATION/TIMING OF CURRENT
PRECIP OVER COLORADO/WESTERN NEBRASKA AND HAVE SLOWED DOWN ONSET
OVER OUR CWA. WHILE THERE IS WEAK FORCING PRESENT AND LIGHT RETURNS
ON RADAR OVER OUR NORTHERN CWA...THIS HAS STRUGGLED TO OVERCOME A
1500-2000 KFT SUB CLOUD DRY LAYER WITH AVERAGE TD DEPRESSIONS 15-
20F. AS SHORTWAVE FINAL BEGINS TO EJECT EASTWARD STRONGER FORCING
AND BETTER LOW LEVEL MOISTURE RETURN WILL ALLOW FOR INCREASE IN SNOW
COVERAGE FROM THE WEST TO THE EAST. I COULD STILL SEE SOME SNOW
BEFORE THIS...BUT HIGHER CONFIDENCE IS FOR AFTER 00Z. LOOKS LIKE WE
SHOULD HAVE A BAND FORM OVER EASTERN COLORADO AND MOVE TOWARDS THE
I70 CORRIDOR BEFORE SLIDING SOUTH AROUND MIDNIGHT. GUIDANCE IS STILL
SHOWING SOME WEAK FORCING IN THE WEST AND LIGHT PRECIP SIGNAL. NOT A
LOT OF CONFIDENCE IN THIS AS WE APPEAR TO BE ON SUBSIDENT SIDE OF H3
JET. MODELS ARE STILL SHOWING SOME WEAK MID LEVEL VORTICITY AND A
LIGHT PRECIP SIGNAL IN THE WEST...SO I KEPT SLIGHT CHANCE/CHANCE IN
PLACE FOR NOW. BASED ON CURRENT TIMING AND HIGHEST CONFIDENCE IS
APPEARS WE COULD SEE A QUICK INCH (MAYBE A LITTLE MORE) WITH THE
SNOW THIS EVENING...WITH HRRR/RAP POSSIBLY SUPPORTING RATES OF 0.5"
PER HOUR. THE PROGRESSIVE NATURE OF THE BAND WILL BE THE LIMITING
FACTOR ON AMOUNTS...WHERE IF IT LINGERS COULD RESULT IN ISOLATED 2-
3" TOTALS. OTHERWISE I WOULD ONLY ANTICIPATE A DUSTING OF ADDITIONAL
SNOW AFTER MIDNIGHT THROUGH MONDAY IF THERE IS ANY SNOW LINGERING AT
THAT POINT. NOT ANTICIPATING ADVISORY LEVEL SNOWS AT THIS
POINT...AND THREAT FOR THAT SEEMS TO BE VERY NARROW/ISOLATED IN OUR
SW.
WHILE THERE WILL BE A SLIGHT INCREASE IN WINDS DURING THE DAY MONDAY
(10-15 MPH GUSTING 20 MPH) THIS LIKELY WONT BE ENOUGH TO CAUSE
MAJOR DRIFTING OR VISIBILITY REDUCTIONS ON ITS OWN. HIGH TEMPS WILL
BE TRICKY WITH A SLIGHT MODERATION OF TEMPS ALOFT MONDAY...FIGHTING
LIMITED DIURNAL HEATING DUE TO CLOUD COVER. BEST CHANCE FOR BREAKS
IN SKY COVER WILL BE IN THE NORTHEAST...WHERE IF THEY DO SEE SOME
SUNSHINE COULD REACH THE LOWER 40S. IF STRATUS LINGER...MOST WONT
SEE HIGHS OUT OF THE 30S.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 315 AM MST MON FEB 16 2015
APOLOGIZE FOR LATENESS ON THIS LONG TERM AFD...MUCH COLLABORATION
AND GRID EDITING WAS NEEDED FROM THE CR INITIALIZATION PROCEDURE.
FORECAST GUIDANCE AND ENSEMBLES HAVE COME INTO MUCH BETTER AGREEMENT
FOR THIS EXTENDED FORECAST RUN. HOWEVER...MAJOR CONCERNS REMAIN...
ESPECIALLY FOR POTENTIAL PRECIPITATION OUTCOMES. OVERALL...COLD
TEMPERATURES ARE ASSURED BUT TIMING AND PLACEMENT OF PRECIPITATION
REMAINS A MAJOR QUESTION MARK.
BEGINNING WITH THURSDAY...WARMEST DAY OF THE PERIOD IS FORECAST.
THIS IS DUE TO BRIEF UPPER LEVEL RIDGING...EMPHASIS ON BRIEF. THIS
ALLOWS SOUTHWEST WINDS ALOFT AND A WARM AIR SURGE EAST FROM THE
COLORADO FRONT RANGE. FRIDAY`S TEMPERATURE FORECAST IS COMPLICATED
AS THERE COULD BE RESIDUAL WARMTH. HOWEVER...A LEE CYCLONE MAY
DEVELOP AND WITH COLD AIR SLIDING SOUTH...CYCLONE MAY AID AN EARLIER
COLD AIR ARRIVAL. MAJOR TEMPERATURE BUST POTENTIAL FRIDAY AS THERE
COULD BE PREFRONTAL MIXING INTO WARMER AIR ALOFT OR THE CYCLONE
PULLING COLD AIR IN FASTER. NOT SURE WHICH SOLUTION WINS SO HAVE
LEFT FRIDAYS TEMPERATURES LARGELY UNTOUCHED. NO PRECIPITATION IS
FORECAST THROUGH FRIDAY.
MAJOR CHANGES ARRIVE FRIDAY NIGHT...LASTING INTO AT LEAST NEXT WEEK.
ACCORDING TO OPERATIONAL RUNS AND ENSEMBLES...LARGE TROUGH OF LOW
PRESSURE DEVELOPS IN NORTHWEST FLOW REGIME...PERSISTING OVER THE
WESTERN UNITED STATES. ADDITIONALLY...LARGE RIDGE OF HIGH PRESSURE
BUILDS OVER THE PACIFIC...EXTENDING NORTH TO CANADA AND ALASKA. THIS
PATTERN IS HIGHLY FAVORABLE FOR ANOTHER ARCTIC OUTBREAK. MODELS ARE
LATCHING ON...INDICATING THE ARCTIC SURFACE HIGH SLIDING SOUTH BY
SATURDAY. LATEST WPC GUIDANCE FORECASTS THE SAME SCENARIO. LARGE
DIFFERENCES REMAIN WITH RESPECT TO SURFACE HIGH STRENGTH AND HOW
COLD WE DROP. GFS BRINGS A 1044 MB HIGH WITH MAX/MIN TEMPS IN THE
30S/TEENS SATURDAY AND 20S/NEAR 10 SUNDAY...WARMING MONDAY. THE
SCARIER SOLUTION IS WHAT ECMWF AND GEFS ENSEMBLE MEAN SUGGEST...A
STRONG ARCTIC HIGH SLIDING SOUTH AND STALLING OVER THE HIGH PLAINS
THROUGH MID-WEEK. ECMWF INDICATES A 1058 MB SURFACE HIGH WHILE THE
GEFS ENSEMBLE MEAN BROADCASTS A 1045+ HIGH. ECMWF AND GEFS ENSEMBLE
MEAN DO NOT ADVANCE THE SURFACE HIGH EAST TO THE GREAT LAKES LIKE
THE OPERATIONAL GFS DOES. AS FOR ECE TEMPERATURES...FORECAST CALLS
FOR MAX/MIN TEMPS SATURDAY IN THE 30S/SINGLE DIGITS AND SUNDAY IN
THE TEENS/NEAR 0. MONDAY WARMS TO THE LOW 20S ACCORDING TO EUROPEAN
GUIDANCE...MUCH COOLER THAN THE OPERATIONAL GFS. NEEDLESS TO SAY...
IT WILL BE QUITE COLD/BELOW NORMAL THIS COMING WEEKEND INTO NEXT
WEEK. THIS PATTERN HAS BEEN DEPICTED BY GUIDANCE FOR SEVERAL RUNS SO
CONFIDENCE IN COLDER TEMPERATURES IS HIGH. LATEST SUPERBLEND LOWERED
TEMPERATURES AND IN COLLABORATION WITH NEIGHBORING OFFICES...FURTHER
DOWNWARD ADJUSTMENTS WERE MADE.
NOW...PRECIPITATION CHANCES. GUIDANCE DISAGREEMENT REMAINS FAIRLY
HIGH WITH RESPECT TO SHORTWAVE TROUGHS/UPPER LEVEL DISTURBANCES FOR
ONE TO FEEL CONFIDENT IN PINPOINTING PRECIP CHANCES. MOST GUIDANCE
INDICATES A STRONG PRECIPITATION SIGNAL FRIDAY NIGHT THROUGH
SATURDAY NIGHT IN ASSOCIATION WITH A STRONG SHORTWAVE MOVING IN.
SUPERBLEND INCREASED POPS TO 40 PERCENT FOR THESE DAYS AND SEE NO
REASON TO DEVIATE. SUNDAY AND BEYOND...AM CONCERNED THAT THE ARCTIC
SURFACE HIGH SLIDING SOUTH COULD CONFINE PRECIPITATION ALONG THE
COLORADO FRONT RANGE WITH COLD BUT DRY CONDITIONS FOR THE HIGH
PLAINS. GLANCING AT SOUNDINGS...VERY COLD TEMPERATURES LEAD TO A
VERY LOW DENDRITIC GROWTH LAYER SO IT WOULD BE EASY FOR PRECIP
DEVELOPMENT IN THAT AIRMASS. FOR NOW...LOWERED POPS DUE TO LOW
CONFIDENCE IN THE EVOLUTION OF ANY PRECIPITATION PRODUCING SYSTEM
BEYOND SATURDAY NIGHT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1000 PM MST SUN FEB 15 2015
KGLD...VFR CONDITIONS EXPECTED THROUGH THE PERIOD. NORTHWEST WINDS
UNDER 10KTS AT TAF ISSUANCE EXPECTED TO CONTINUE THROUGH 19Z
BEFORE INCREASING TO 12KTS FROM 20Z-23Z. AFTER 23Z WINDS SLOWLY
BACK TO THE WEST-SOUTHWEST NEAR 10KTS. CLOUDINESS PRIMARILY MID
AND UPPER LEVELS. WILL HAVE TO WATCH FOR SOME MVFR CLOUDINESS FROM
TAF ISSUANCE THROUGH 15Z PER NAM AND LESSER EXTENT RUC MOISTURE
CROSS-SECTIONS. MODELS ALSO RATHER PERSISTENT IN PRODUCING SOME
FOG/MIST DURING THE SAME TIME PERIOD. WITH KITR RECENTLY DROPPING
TO IFR CIGS WILL BEGIN THE PERIOD WITH A TEMPO GROUP FOR IFR CIGS.
KMCK...VFR CONDITIONS EXPECTED THROUGH THE PERIOD. LIGHT/VARIABLE
WINDS AT TAF ISSUANCE EXPECTED TO BECOME NORTHWEST AROUND 6KTS BY
09Z THEN 13KTS FROM 20Z-22Z BEFORE DECREASING TO 10KTS BY 23Z.
WEST-NORTHWEST WINDS AROUND 7KTS EXPECTED AFTER 05Z. CLOUDINESS
CONFINED TO MID AND UPPER LEVELS THROUGH 19Z BEFORE DECREASING BUT
REMAINING VFR FOR THE REST OF THE TAF PERIOD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...99
SHORT TERM...DR
LONG TERM...RRH
AVIATION...99
AREA FORECAST DISCUSSION
NWS CARIBOU ME
1004 AM EST MON FEB 16 2015
.SYNOPSIS...
AN INTENSE AREA OF LOW PRESSURE WILL CONTINUE TO LIFT NORTH OF
MARITIMES TODAY. HIGH PRESSURE ACROSS THE MIDWEST WILL BUILD
TOWARD THE REGION LATER TONIGHT THROUGH TUESDAY. LOW PRESSURE WILL
PASS SOUTH OF THE AREA TUESDAY. ANOTHER LOW WILL DEVELOP IN THE
GULF OF MAINE WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
THE MAIN IMPACTS WILL BE WINDS LEADING TO BLOWING AND DRIFTING
SNOW AND THE DANGEROUS WIND CHILLS.
930 AM UPDATE: WE XTNDED THE WNTR WX ADV FOR BLOWING AND DRIFTING
SN TIL 18Z. MANY LCTNS WHO RECEIVED SN FROM THE MOST RECENT PAST
SN EVENT ARE CURRENTLY EXPERIENCING NW WIND GUSTS IN THE 40 TO 45
MPH RANGE...CREATING DANGEROUS WHITEOUTS ON ROADWAYS WITH OPEN
TERRAIN. OTHERWISE...WE XTNDED THE WIND CHILL ADV FOR THE CNTRL
HIGHLANDS AND NW TIL 18Z AS WELL...CANCELLING THE WIND CHILL ADV
FOR ZONES 15...16 AND 17 WHERE WIND CHILLS SHOULD MODERATE TO A
LITTLE WARMER THAN 20 BELOW. OTHERWISE...FCST HRLY CLD CVR AND
TEMPS WERE MODIFIED BASED ON RECENT SAT IMAGERY AND SFC OBS.
ORGNL DISC: 09Z SURFACE ANALYSIS SHOWED 960MB LOW MOVING ACROSS
THE MARITIMES. VERY STRONG GRADIENT IN PLACE ACROSS THE CWA
W/SUSTAINED WINDS 25 TO 35 MPH AND GUSTS AS HIGH AS 45 MPH. SOME
ELEVATED SITES SUCH AS KFVE(FRENCHVILLE) HAD GUSTS TO 50+ MPH
OVERNIGHT. THE STRONG WINDS WILL CONTINUE INTO THE AFTERNOON AND
THEN GRADUALLY LET UP THIS EVENING INTO THE OVERNIGHT HOURS AS THE
GRADIENT LOOSENS. SOUNDING PROFILES SHOWED GUST POTENTIAL TO 50
MPH AGAIN THIS MORNING INTO EARLY AFTERNOON ESPECIALLY ACROSS
NORTHERN AND EASTERN MAINE(WASHINGTON COUNTY). CENTRAL AND
DOWNEAST AREAS WILL SEE GUSTS HIT 40 MPH AT TIMES W/ANOTHER SURGE
AS SHOWN BY THE SOUNDINGS. THIS WILL LEAD TO BLOWING AND DRIFTING
SNOW W/TRAVEL BEING HAZARDOUS AT TIMES. HANCOCK AND WASHINGTON
COUNTIES WILL EXPERIENCE MUCH OF THIS AND SNOW REMOVAL COULD BE
HAMPERED FOR A TIME. RADAR LOOP SHOWED SOME LIGHT SNOW CONTINUING
WHICH WILL ADD TO THE MIX THIS MORNING. THE SNOW IS FORECAST TO
END BY MID MORNING AS FORCING WEAKENS W/THE LOW LIFTING N. THE
NAM12 AND RAP GUIDANCE WERE DOING A FINE JOB W/THIS SETUP.
VERY COLD TEMPERATURES AND THE CONTINUED WINDY CONDITIONS WILL
LEAD TO DANGEROUS WIND CHILLS TODAY AND AGAIN TONIGHT. WE COULD
ACTUALLY BE SEEING WIND CHILL HEADLINES FOR THE ENTIRE REGION BY
TONIGHT INTO TUESDAY MORNING. STAYED PRETTY CLOSE TO THE DAYCREW`S
ASSESSMENT IN THE TEMPERATURES W/SINGLE NUMBERS ALL THE WAY TO
THE COAST. BELOW ZERO TEMPERATURES OVERNIGHT FOR THE ENTIRE CWA
W/THE NORTHERN AREAS POSSIBLY SEEING 15 TO 20 BELOW ESPECIALLY IN
SHELTERED LOCATIONS.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
LOW PRESSURE WILL TRACK NORTHEAST FROM THE MID ATLANTIC REGION
EARLY TUESDAY AND THEN TO THE SOUTH OF NOVA SCOTIA TUESDAY NIGHT.
THIS SYSTEM COULD CLIP DOWN EAST MAINE...MAINLY THE COAST WITH A
LITTLE LIGHT SNOW ON TUESDAY BUT AT THIS TIME LITTLE IF ANY
ACCUMULATION IS EXPECTED. OTHERWISE TUESDAY IS SHAPING UP AS
ANOTHER UNSEASONABLY COLD BUT DRY DAY WITH HIGHS GENERALLY IN THE
TEENS MOST AREAS. EXPECT PARTLY TO MOSTLY CLOUDY SKIES TUESDAY
NIGHT. THE NEXT CHANCE FOR SNOW WILL COME LATER WEDNESDAY AS A
NORLUN TROF TYPE FEATURE DEVELOPS IN THE WAKE OF THE DEPARTING
LOW. AT THIS POINT IT APPEARS THE BEST CHANCE FOR SNOW WILL BE
ACROSS THE SOUTHWEST PORTION OF THE FA THROUGH THE DAY WEDNESDAY.
ANY SNOW ACCUMULATIONS THROUGH THE DAY WEDNESDAY SHOULD BE ON THE
LIGHT SIDE.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
WEDNESDAY NIGHTS AND THURSDAY`S WEATHER WILL BE FOCUSED ON THE
DEVELOPMENT AND PLACEMENT OF A NORLUN TROF TYPE FEATURE AND WEAK
AREA OF LOW PRESSURE THAT IS EXPECTED TO TAKE SHAPE ALONG THE
MAINE MID COAST. MODELS ARE IN VERY GOOD AGREEMENT REGARDING THE
PLACEMENT OF THESE FEATURES FOR WEDNESDAY NIGHT AND THURSDAY.
DECIDED TO RAISE POPS TO CATEGORICAL ACROSS THE ENTIRE AREA
WEDNESDAY NIGHT AND INTO THURSDAY AS JUST ABOUT ALL AREAS SHOULD
SEE SOME SNOW. AT THIS TIME IT LOOKS LIKE GENERALLY LIGHT SNOW
ACCUMULATIONS ARE EXPECTED. THIS SYSTEM WILL MOVE AWAY THURSDAY
NIGHT WITH CONTINUED UNSEASONABLY COLD AND MAINLY DRY CONDITIONS
THURSDAY NIGHT AND FRIDAY WITH NOTHING MORE THAN A FEW SNOW
SHOWERS ACROSS NORTHERN AREAS. LOOKING AHEAD...ANOTHER SYSTEM MAY
MAKE A RUN AT THE AREA LATER SATURDAY INTO SUNDAY WITH A CHANCE
FOR MORE SNOW.
&&
.AVIATION /15Z MONDAY THROUGH FRIDAY/...
NEAR TERM: IFR ACROSS THE NORTHERN TERMINALS THROUGH MIDDAY AND
THEN MVFR ESPECIALLY W/VSBYS AND BLOWING SNOW. CONDITIONS LOOK TO
IMPROVE TO VFR THIS EVENING INTO THE OVERNIGHT PERIOD. KBGR AND
KBHB SHOULD SEE VFR RIGHT INTO TONIGHT. TURBULENCE WILL BE A
CONCERN TODAY W/GUSTS HITTING 35-40KT ESPECIALLY THE NORTHERN
TERMINALS.
SHORT TERM: VFR CONDITIONS ARE EXPECTED TUESDAY AND TUESDAY
NIGHT. VFR EXPECTED MOST OF WEDNESDAY. SNOW WILL DEVELOP WEDNESDAY
NIGHT AND CONTINUE INTO THURSDAY WITH IFR CONDITIONS LIKELY.
CONDITIONS WILL IMPROVE TO VFR THURSDAY NIGHT AND FRIDAY.
&&
.MARINE...
NEAR TERM: AFTER COORDINATING W/GYX, DECIDED TO LOWER THE STORM
WARNING TO A GALE WARNING. GUST POTENTIAL OF 40-45 KT EXPECTED
EARLY TODAY. SUSTAINED WINDS OF 30-35 KT INTO EARLY TONIGHT. IT
DOES LOOK AS THOUGH THE CONDITIONS WILL TRANSITION TO SCA AFTER
MIDNIGHT. HEAVY FREEZING SPRAY EXPECTED RIGHT INTO THE AFTERNOON
AND THE WARNING WAS EXTENDED THROUGH 7 PM. CONDITIONS WILL IMPROVE
LATER IN THE EVENING AS THE WINDS DROP OFF. LOOKS LIKE MODERATE
FREEZING SPRAY BY LATE EVENING INTO THE OVERNIGHT HOURS.
SHORT TERM: WIND/SEAS SHOULD REMAIN BELOW SMALL CRAFT ADVISORY
LEVELS TUESDAY THROUGH WEDNESDAY. SCA CONDITIONS ARE THEN POSSIBLE
AGAIN BY THURSDAY. LIGHT FREEZING SPRAY IS EXPECTED TUESDAY
THROUGH WEDNESDAY.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
MEZ002-005-006-011-017-030-032.
WIND CHILL ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR MEZ001-
003-004-010-031.
MARINE...HEAVY FREEZING SPRAY WARNING UNTIL 7 PM EST THIS EVENING FOR
ANZ050>052.
GALE WARNING UNTIL 1 AM EST TUESDAY FOR ANZ050>052.
&&
$$
NEAR TERM...VJN
SHORT TERM...DUDA
LONG TERM...DUDA
AVIATION...VJN/DUDA
MARINE...VJN/DUDA
AREA FORECAST DISCUSSION
NWS CARIBOU ME
612 AM EST MON FEB 16 2015
.SYNOPSIS...
AN INTENSE AREA OF LOW PRESSURE WILL CONTINUE TO LIFT NORTH OF
MARITIMES TODAY. HIGH PRESSURE ACROSS THE MIDWEST WILL BUILD
TOWARD THE REGION LATER TONIGHT THROUGH TUESDAY. LOW PRESSURE WILL
PASS SOUTH OF THE AREA TUESDAY. ANOTHER LOW WILL DEVELOP IN THE
GULF OF MAINE WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
THE MAIN IMPACTS WILL BE WINDS LEADING TO BLOWING AND DRIFTING
SNOW AND THE DANGEROUS WIND CHILLS.
610 AM UPDATE: ADJUSTED THE POPS TO LOWER THE PERCENTAGES AND MOVE
THE PLACEMENT FURTHER E AS DEPICTED ON RADAR. SOME MINOR
ADJUSTMENTS WERE MADE TO THE WINDS/GUSTS INITIALLY TO LINE UP
W/THE LAST 3HRS. STILL GETTING GUSTS OF 50+ MPH ACROSS FAR
NORTHERN MAINE ESPECIALLY IN THE ST. JOHN VALLEY. KFVE HAD A PEAK
GUST TO 52 KTS AT 523 AM. WIND CHILL READINGS ARE DROPPING AND
SOME SOME SITES ARE WELL IN THE ADVISORY RANGE W/SOME SITES
HOVERING NEAR WARNING CRITERIA. ATTM, WILL KEEP THE HEADLINES
WHERE THEY ARE AND LET THE DAYCREW RE-ASSESS THE SITUATION.
09Z SURFACE ANALYSIS SHOWED 960MB LOW MOVING ACROSS THE
MARITIMES. VERY STRONG GRADIENT IN PLACE ACROSS THE CWA
W/SUSTAINED WINDS 25 TO 35 MPH AND GUSTS AS HIGH AS 45 MPH. SOME
ELEVATED SITES SUCH AS KFVE(FRENCHVILLE) HAD GUSTS TO 50+ MPH
OVERNIGHT. THE STRONG WINDS WILL CONTINUE INTO THE AFTERNOON AND
THEN GRADUALLY LET UP THIS EVENING INTO THE OVERNIGHT HOURS AS THE
GRADIENT LOOSENS. SOUNDING PROFILES SHOWED GUST POTENTIAL TO 50
MPH AGAIN THIS MORNING INTO EARLY AFTERNOON ESPECIALLY ACROSS
NORTHERN AND EASTERN MAINE(WASHINGTON COUNTY). CENTRAL AND
DOWNEAST AREAS WILL SEE GUSTS HIT 40 MPH AT TIMES W/ANOTHER SURGE
AS SHOWN BY THE SOUNDINGS. THIS WILL LEAD TO BLOWING AND DRIFTING
SNOW W/TRAVEL BEING HAZARDOUS AT TIMES. HANCOCK AND WASHINGTON
COUNTIES WILL EXPERIENCE MUCH OF THIS AND SNOW REMOVAL COULD BE
HAMPERED FOR A TIME. RADAR LOOP SHOWED SOME LIGHT SNOW CONTINUING
WHICH WILL ADD TO THE MIX THIS MORNING. THE SNOW IS FORECAST TO
END BY MID MORNING AS FORCING WEAKENS W/THE LOW LIFTING N. THE
NAM12 AND RAP GUIDANCE WERE DOING A FINE JOB W/THIS SETUP.
VERY COLD TEMPERATURES AND THE CONTINUED WINDY CONDITIONS WILL
LEAD TO DANGEROUS WIND CHILLS TODAY AND AGAIN TONIGHT. WE COULD
ACTUALLY BE SEEING WIND CHILL HEADLINES FOR THE ENTIRE REGION BY
TONIGHT INTO TUESDAY MORNING. STAYED PRETTY CLOSE TO THE DAYCREW`S
ASSESSMENT IN THE TEMPERATURES W/SINGLE NUMBERS ALL THE WAY TO
THE COAST. BELOW ZERO TEMPERATURES OVERNIGHT FOR THE ENTIRE CWA
W/THE NORTHERN AREAS POSSIBLY SEEING 15 TO 20 BELOW ESPECIALLY IN
SHELTERED LOCATIONS.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
LOW PRESSURE WILL TRACK NORTHEAST FROM THE MID ATLANTIC REGION
EARLY TUESDAY AND THEN TO THE SOUTH OF NOVA SCOTIA TUESDAY NIGHT.
THIS SYSTEM COULD CLIP DOWN EAST MAINE...MAINLY THE COAST WITH A
LITTLE LIGHT SNOW ON TUESDAY BUT AT THIS TIME LITTLE IF ANY
ACCUMULATION IS EXPECTED. OTHERWISE TUESDAY IS SHAPING UP AS
ANOTHER UNSEASONABLY COLD BUT DRY DAY WITH HIGHS GENERALLY IN THE
TEENS MOST AREAS. EXPECT PARTLY TO MOSTLY CLOUDY SKIES TUESDAY
NIGHT. THE NEXT CHANCE FOR SNOW WILL COME LATER WEDNESDAY AS A
NORLUN TROF TYPE FEATURE DEVELOPS IN THE WAKE OF THE DEPARTING
LOW. AT THIS POINT IT APPEARS THE BEST CHANCE FOR SNOW WILL BE
ACROSS THE SOUTHWEST PORTION OF THE FA THROUGH THE DAY WEDNESDAY.
ANY SNOW ACCUMULATIONS THROUGH THE DAY WEDNESDAY SHOULD BE ON THE
LIGHT SIDE.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
WEDNESDAY NIGHTS AND THURSDAYS WEATHER WILL BE FOCUSED ON THE
DEVELOPMENT AND PLACEMENT OF A NORLUN TROF TYPE FEATURE AND WEAK
AREA OF LOW PRESSURE THAT IS EXPECTED TO TAKE SHAPE ALONG THE
MAINE MID COAST. MODELS ARE IN VERY GOOD AGREEMENT REGARDING THE
PLACEMENT OF THESE FEATURES FOR WEDNESDAY NIGHT AND THURSDAY.
DECIDED TO RAISE POPS TO CATEGORICAL ACROSS THE ENTIRE AREA
WEDNESDAY NIGHT AND INTO THURSDAY AS JUST ABOUT ALL AREAS SHOULD
SEE SOME SNOW. AT THIS TIME IT LOOKS LIKE GENERALLY LIGHT SNOW
ACCUMULATIONS ARE EXPECTED. THIS SYSTEM WILL MOVE AWAY THURSDAY
NIGHT WITH CONTINUED UNSEASONABLY COLD AND MAINLY DRY CONDITIONS
THURSDAY NIGHT AND FRIDAY WITH NOTHING MORE THAN A FEW SNOW
SHOWERS ACROSS NORTHERN AREAS. LOOKING AHEAD...ANOTHER SYSTEM MAY
MAKE A RUN AT THE AREA LATER SATURDAY INTO SUNDAY WITH A CHANCE
FOR MORE SNOW.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
NEAR TERM: IFR ACROSS THE NORTHERN TERMINALS THROUGH MIDDAY AND
THEN MVFR ESPECIALLY W/VSBYS AND BLOWING SNOW. CONDITIONS LOOK TO
IMPROVE TO VFR THIS EVENING INTO THE OVERNIGHT PERIOD. KBGR AND
KBHB SHOULD SEE VFR RIGHT INTO TONIGHT. TURBULENCE WILL BE A
CONCERN TODAY W/GUSTS HITTING 35-40KT ESPECIALLY THE NORTHERN
TERMINALS.
SHORT TERM: VFR CONDITIONS ARE EXPECTED TUESDAY AND TUESDAY
NIGHT. VFR EXPECTED MOST OF WEDNESDAY. SNOW WILL DEVELOP WEDNESDAY
NIGHT AND CONTINUE INTO THURSDAY WITH IFR CONDITIONS LIKELY.
CONDITIONS WILL IMPROVE TO VFR THURSDAY NIGHT AND FRIDAY.
&&
.MARINE...
NEAR TERM: AFTER COORDINATING W/GYX, DECIDED TO LOWER THE STORM
WARNING TO A GALE WARNING. GUST POTENTIAL OF 40-45 KT EXPECTED
EARLY TODAY. SUSTAINED WINDS OF 30-35 KT INTO EARLY TONIGHT. IT
DOES LOOK AS THOUGH THE CONDITIONS WILL TRANSITION TO SCA AFTER
MIDNIGHT. HEAVY FREEZING SPRAY EXPECTED RIGHT INTO THE AFTERNOON
AND THE WARNING WAS EXTENDED THROUGH 7 PM. CONDITIONS WILL IMPROVE
LATER IN THE EVENING AS THE WINDS DROP OFF. LOOKS LIKE MODERATE
FREEZING SPRAY BY LATE EVENING INTO THE OVERNIGHT HOURS.
SHORT TERM: WIND/SEAS SHOULD REMAIN BELOW SMALL CRAFT ADVISORY
LEVELS TUESDAY THROUGH WEDNESDAY. SCA CONDITIONS ARE THEN POSSIBLE
AGAIN BY THURSDAY. LIGHT FREEZING SPRAY IS EXPECTED TUESDAY
THROUGH WEDNESDAY.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR
MEZ002-005-006-011-017-030-032.
WIND CHILL ADVISORY UNTIL 10 AM EST THIS MORNING FOR MEZ001-
003-004-010-015-016-029-031.
MARINE...HEAVY FREEZING SPRAY WARNING UNTIL 7 PM EST THIS EVENING FOR
ANZ050>052.
GALE WARNING UNTIL 1 AM EST TUESDAY FOR ANZ050>052.
&&
$$
NEAR TERM...HEWITT
SHORT TERM...DUDA
LONG TERM...DUDA
AVIATION...HEWITT/DUDA
MARINE...HEWITT/DUDA
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1042 AM EST MON FEB 16 2015
.SYNOPSIS...
LOW PRESSURE WILL TRACK SOUTH OF THE REGION TONIGHT AND EARLY
TUESDAY FOLLOWED BY ANOTHER BLAST OF ARCTIC AIR THAT WILL MOVE
INTO THE REGION FOR THE MID TO LATE WEEK PERIOD.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPPER LOW AND THE CORE OF COLDEST AIR WILL BE LIFTING OUT OF THE
AREA EARLY TODAY.
COLDEST TEMP SO FAR WAS -32 AT CHANDLER`S VALLEY.
SATELLITE LOOP SHOWS CLOUDS CONTINUING TO INCREASE OVER THE REGION
WITH SURFACE OBS SHOWING THE NEAREST SNOW HITTING THE GROUND FROM
SOUTHERN OHIO DOWN INTO CENTRAL WEST VA.
LATEST HRRR HAS LIGHT SNOW OVERSPREADING SWRN AREAS DURING THE
LATTER HALF OF THE AFTERNOON INTO THE EVENING. THE EVENING COMMUTE
COULD BECOME SLIPPERY OVER MY SWRN ZONES WITH SNOW EXPECTED TO
BEGIN IN THE 21-00Z/4-7PM TIMEFRAME.
I NUDGED SNOW AMOUNTS DOWN A BIT TO FIT LATEST GUIDANCE. LOOKING
AT THE BEST LAYER FRONTOGENETIC FORCING FROM THE NEW NAM SUGGESTS
THE AXIS OF HEAVIEST SNOW WILL BE SOUTH OF THE PA-MD BORDER...WITH
PERHAPS FAR SRN LANCASTER-YORK COUNTIES PICKING UP SLIGHTLY HIGHER
AMOUNTS AS THE BEST WARM ADVECTION/FRONTOGENESIS MOVES THROUGH
OVERNIGHT.
WILL CONTINUE THE WINTER WEATHER ADVISORY WITH NO PLANNED CHANGES
AT THIS POINT IN TIME...FOR THE SOUTHERN 2 LAYERS OF COUNTIES IN
OUR CWA. THE SOUTHERN TIER IS EXPECTED TO SEE BETWEEN 2 AND 5
INCHES OF SNOW BY THE MORNING COMMUTE TUESDAY...WHILE COUNTY-
LAYER WITHIN THE RT 22/322 CORRIDOR SHOULD SEE MORE ALONG THE
LINES OF 1-3 INCHES. LESSER AMOUNTS OF AROUND 1-2 INCHES ARE
ANTICIPATED TO FALL RIGHT ALONG INTERSTATE 80...WITH AN INCH OR
LESS ACROSS THE MTNS OF NRN PENN.
HIGH TEMPS TODAY WILL REBOUND TO NEAR 10 ACROSS THE NORTHERN
MOUNTAINS...AND REACH THE MID TO UPPER TEENS IN FAR S-CENT AND
SOUTHEASTERN PA.
&&
.SHORT TERM /TUESDAY/...
THE BROAD AREA OF WEAK TO MDT DEEP-LAYER UVVEL ASSOCIATED WITH THE
COUPLED UPPER JET WILL SCOOT QUICKLY EAST OF THE REGION TUESDAY
MORNING FOLLOWED BY WEST-SOUTHWESTERLY FLOW IN THE LOW TO MID
LEVELS...WITH PARTIAL CLEARING IN THE AFTERNOON.
TEMPS DURING THE DAY TUESDAY WILL WARM BY ANOTHER 10F /COMPARED
TO TODAY`S HIGHS/. IT`S PRETTY AMAZING THAT EVEN AFTER THE
UPCOMING 2 DAYS OF MODERATING TEMPS...HIGHS TUESDAY WILL STILL BE
15 DEG F BELOW NORMAL FOR THE DATE.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
VERY COLD AIR WILL CONTINUE TO IMPACT THE REGION THROUGH AT LEAST
THE UPCOMING WORK-WEEK AS A STRONG UPPER LEVEL RIDGE REMAINS OVER
THE WESTERN U.S. AND CONTINUES TO DIRECT POLAR AIR INTO THE
EASTERN U.S. VIA PERSISTENT TROUGH.
SHORT WAVE ENERGY IS FORECAST TO CROSS THE INTO THE PAC LATE IN
THE WEEK AND DIG INTO THE FOUR CORNERS REGION AS THE UPPER RIDGE
REBUILDS NWD INTO WRN CANADA. THIS WILL SHIFT THE UPPER TROF AXIS
NOW COVERING THE EASTERN U.S. - WESTWARD. THIS IN TURN WILL LEAD
TO A FLATTENING OF THE UPPER FLOW OVER THE NORTHEAST NEXT WEEKEND
AND A MODERATION AWAY FROM THE BITTER COLD IN THE CURRENT PATTERN.
PRIOR TO THIS LATE WEEK...LARGE SCALE FLOW MODIFICATION WE`LL HAVE
TO DEAL WITH ONE MORE ARCTIC BLAST...THE LEADING EDGE OF WHICH
WILL PUSH ACROSS THE STATE DURING THE DAY WEDNESDAY. SOMEWHAT
SIMILAR TO SATURDAY...WE SEE A WELL-DEFINED AREA OF STEEP 850-500
MB LAPSE RATES AROUND...OR IN EXCESS OF 7C/KM THAT WILL MOVE
ACROSS THE WESTERN MTNS DURING THE EARLY TO MID AFTERNOON...AND
THROUGH THE SUSQ VALLEY EARLY WED EVENING. ALTHOUGH LIKELY NOT AS
EXTENSIVE AND CONSISTENTLY INTENSE OF A LINE THAT WE SAW SATURDAY
/COMPLETE WITH FEW FLASHES OF LIGHTNING IN SOME LOCATIONS/...THE
SQUALLS ASSOCIATED WITH THIS RIBBON OF INSTABILITY WED WILL LIKELY
COME IN THE FORM ONE OR TWO LINES...AND DUMP A QUICK .5 TO 1.5
INCHES OF SNOW - GREATLY IMPACTING TRAVEL FOR A SHORT PERIOD.
BEHIND THIS SYSTEM YET ANOTHER SURGE OF EXTREMELY COLD AIR WILL
SURGE ACROSS THE STATE FOR THE SECOND HALF OF THE WEEK.
SIMILAR...EXTREMELY COLD TEMPS AT 850 MB ARE FORECAST TO MOVE OVER
THE STATE THURSDAY AND FRIDAY /AND COULD BE EVEN A FEW DEG C LOWER
THAN THOSE ASSOCIATED WITH THIS PAST SUNDAY-MONDAY ARCTIC
AIRMASS/. 03Z SREF SHOWS MEAN 850 TEMPS OF -25 TO -28C COVERING
ALL OF CENTRAL PENN WHICH IS ABOUT -3 SIGMA. HIGH TEMPS THURSDAY
MAY STAY A FEW-SVRL DEG F BELOW ZERO AGAIN ACROSS THE NRN
MTNS...AND HOLD IN THE SINGLE DIGITS TO LOWER TEENS ACROSS THE
REST OF CENTRAL AND SRN PENN...BEFORE MODERATING BY 5-7 DEG
FRIDAY. MORNING LOWS THURSDAY AND FRIDAY COULD RIVAL THOSE OF
SUNDAY AND MONDAY MORNING.
THE CENTER OF THIS NEXT ARCTIC HIGH MAY SLIDE JUST SOUTH OF THE
REGION THEN OFF THE MID ATLANTIC COAST - PER THE 00Z EC...WHILE
THE GEFS WOULD SUGGEST A LITTLE MORE IN THE WAY OF LLVL COLD AIR
DAMMING OVER THE CWA...PRECEDING INCREASING MOISTURE AND A WINTRY
MIX OR SNOW SPREADING IN FROM THE SW...THEN ANOTHER PUSH OF
ARCTIC AIR FOR LATE SUNDAY AND MONDAY.
TEMPERATURES NEXT SUNDAY...HOWEVER...HOLD THE POTENTIAL TO RISE
ABOVE THE FREEZING MARK OVER A GOOD PART OF CENTRAL PA AS THE
EARLIER MENTIONED MODERATION IN THE UPPER FLOW IS FORECAST TO
ARRIVE. THE NEXT SHORTWAVE TROF IS ALSO CURRENTLY TIMED FOR NEXT
WEEKEND...LEADING TO THE POSSIBILITY OF SNOW OR RAIN FOR A CHANGE
OVER SRN PA AND SNOW OVER THEN NORTH.
&&
.AVIATION /16Z MONDAY THROUGH FRIDAY/...
VFR WITH NO SIG WX CONDITIONS THROUGH THE AFTERNOON. INCR MID-HIGH
CLOUDS AOA 12KFT AGL. WINDS FROM 280-320 WILL CONTINUE TO
DIMINISH BCMG LGT AND VRB AS SFC HIGH PRESSURE DRIFTS OVER THE
AIRSPACE.
LOW PRESSURE MOVING NEWD FROM AL OFF THE MID ATLC COAST
BTWN 00-12Z TUE WILL SPREAD SNOW AND IFR CONDS ACROSS THE SRN 1/2
OF THE AIRSPACE LATER THIS AFTERNOON INTO THE OVERNIGHT. SNOW
WILL BE QUICK- HITTING AND END BY 15-18Z TUE FROM WEST TO EAST.
HIGHEST CONFIDENCE IN IFR IS OVER THE SRN AIRFIELDS. USED A BLEND
OF HIGH RES MDLS FOR TIMING WITH -SN ONSET 21-00Z SPREADING FROM
SW TO NE.
OUTLOOK...
WED-THU...MVFR/IFR -SHSN WRN 1/3. VFR/MVFR -SHSN CENTRAL/ERN 2/3
FRI...BCMG VFR. NO SIG WX.
&&
.CLIMATE...
RECORD LOW TEMPERATURES FOR 2/16 IN JEOPARDY AT MANY SITES.
CHANDLER VALLEY COOP REPORTED -32F AT 0645 AM. TO PUT THE EXTREME
COLD INTO PERSPECTIVE...THE PA STATE RECORD LOW IS -42F AT
SMETHPORT ON 1/5/1904.
RECORD LOW/YEAR
HARRISBURG.............0/1905
WILLIAMSPORT..........-5/1905 STATE COLLEGE.........-8/1904
YORK..................-7/1963 ALTOONA...............-2/2004
BRADFORD..............-23/1943 CLEARFIELD............-6/1930
JOHNSTOWN.............-10/1943 LANCASTER.............+2/1987
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 7 AM EST
TUESDAY FOR PAZ024>028-033>036-056-057-059-063>066.
&&
$$
SYNOPSIS...LA CORTE/LAMBERT
NEAR TERM...LA CORTE/LAMBERT
SHORT TERM...FITZGERALD/LAMBERT
LONG TERM...LAMBERT/GARTNER
AVIATION...LA CORTE/STEINBUGL
CLIMATE...
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1027 AM EST MON FEB 16 2015
.SYNOPSIS...
A MOIST LOW PRESSURE SYSTEM WILL TRACK THROUGH THE SOUTHEAST STATES
TODAY SPREADING WINTRY PRECIPITATION ACROSS THE FORECAST AREA INTO
EARLY TUESDAY. IN ITS WAKE...AN ARCTIC COLD FRONT WILL SWEEP THROUGH
FROM THE NORTH WEDNESDAY. COLD HIGH PRESSURE WILL THEN BUILD IN AND
PERSIST THROUGH FRIDAY...BEFORE A MOIST SURFACE BOUNDARY MOVES INTO
THE AREA OVER THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1020 AM EST...THE SFC LOW CENTER WAS ANAYLYZED OVER THE LOWER
MS RIVER VALLEY...WITH A LARGE PRECIPITATION SHIELD EXTENDING NWD
ACROSS THE MID SOUTH INTO THE OH VALLEY. A BROAD AREA OF HEAVY ICING
HAS DEVELOPED ACROSS WRN AND CENTRAL TN AND THIS WILL CONTINUE TO
MOVE EASTWARD TOWARD/INTO THE SRN APPALACHIANS THROUGH EARLY AFTN.
THE MAIN POINTS OF CONCERN FOR THE FORECAST INCLUDE...SLIGHTLY MORE
BREAKS IN CLOUDS ACROSS THE FORECAST AREA THIS MORNING ALLOWING
TEMPS TO RUN A FEW DEGREES ABOVE GUIDANCE...AND ALSO THE LATEST RAP
MODEL TRENDS OF QUICKLY WARMING SFC WET BULB TEMPERATURES ABOVE
FREEZING ACROSS THE SRN HALF BY THE TIME THE HEAVIER PRECIPITATION
ARRIVES LATE AFTN/EVENING. THE LATEST NAM AND GFS ARE MUCH COLDER
WITH SFC WET BULBS AND THE SREF MEAN IS A COMPROMISE...WITH THE MAIN
WARMING OVER THE NE GA FOOTHILLS/PIEDMONT AND WRN SC UPSTATE. THE
ONE CERTAINTY IS THAT QPF SHOULD BE SUFFICIENT FOR SIGNIFICANT
WINTRY PRECIP IN ANY AREAS WHERE THE PROFILES SUPPORT WINTER TYPES.
WILL THUS SHARPEN UP THE GRADIENT OF SNOW AND ICE ACCUMS ACROSS THE
FORECAST AREA...WITH MOSTLY COLD RAIN NOW EXPECTED FROM TOCCOA TO
ANDERSON TO LAURENS TO CHESTER...BUT WITH A VERY SHARP TRANSITION TO
SIGNIFICANT ICING FROM THE GA MTNS TO GREENVILLE/SPARTANBURG TO ROCK
HILL/CHARLOTTE/MONROE. NRN BLUE RIDGE AREA SNOW TOTALS HAVE BEEN
INCREASED SLIGHTLY AS WELL...BUT AGAIN SOME SLEET WILL MIX IN AT
TIMES TO SLIGHTLY CURB TOTALS BELOW WHAT QPF INDICATES. WILL
CONTINUE TO FOLLOW 4 KM WRF AND HRRR CONSENSUS ON ARRIVAL TIMES
ACROSS THE REGION.
DRY SLOTTING IS EXPECTED AT MID LEVELS FROM THE SW OVERNIGHT...AND
THE HEAVIER PRECIP SHOULD CUT OFF FAIRLY RAPIDLY. HOWEVER...COLD AIR
WILL QUICKLY RETURN FROM THE NW TO PRODUCE A TRANSITION BACK OVER TO
SNOW FOR ANY NW FLOW PRECIPITATIO THROUGH DAYBREAK. NO CHANGES IN THE
WARNING/ADVISORY PRODUCTS HAVE BEEN MADE...BUT THE GRADIENT AMONG
ALL SNOW/ICE ACCUMS HAS BEEN SHARPENED.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 300 AM MONDAY...THE 00Z MODELS ARE IN VERY GOOD AGREEMENT ON
THE BACK EDGE OF THE PRECIP SHIELD PRETTY MUCH COMPLETELY EXITED OFF
TO THE EAST BY 12Z TUESDAY...EXCEPT FOR SOME LINGER NW FLOW CHCS FOR
TUESDAY MORNING. OTHERWISE...TUESDAY LOOKS LIKE A COLD DAY...WITH
PERSISTENT 850 MB CAA ALL DAY. TEMPS DO REBOUND FROM SUN-MON
READINGS...BUT STILL 10-15 DEG BELOW NORMAL (20S TO UPR 30S MTNS AND
MAINLY LWR-MID 40S PIEDMONT).
TUESDAY NIGHT THRU WEDNESDAY NIGHT...ANOTHER PIECE OF THE POLAR
VORTEX WILL DIG INTO THE GREAT LAKES...AND BRING TWO SHOTS OF
REINFORCING ARCTIC AIR. THE FIRST WILL BE WEDNESDAY MORNING...WITH
STRONG CAA AND SOME LLVL MOISTURE FOR NW FLOW SNOW SHWR ACTIVITY.
THE SECOND (STRONGER) FRONT WILL CROSS THE AREA WEDNESDAY NIGHT. THE
MAIN CONCERN WITH THE FIRST FRONT WILL BE SNOW ALONG THE TN BORDER.
GUIDANCE HAS TRENDED A LITTLE WETTER...BUT LIKE THE LAST FEW FRONTS
OF THIS NATURE...THE TIME INTERVAL IS RATHER SHORT...AND GENERALLY
SUB-ADV ACCUMS ARE EXPECTED. I DID BUMP UP POP FOR WEDNESDAY IN THE
NC MTNS. THE OP MODELS AGREE ON STEEP LLVL LAPSE RATES ACRS THE
PIEDMONT WITH AT LEAST A SLGT CHC OF A FEW SHWRS BREAKING
CONTAINMENT FROM THE TN LINE WED AFTN. I INTRODUCED A SLGT CHC OF
SNOW SHWRS ACRS THE NC PIEDMONT. NO ACCUMS EXPECTED...BUT AN ISOLD
DUSTING LOOKS POSSIBLE. TEMPS WEDNESDAY WILL BE 2-3 CATEGORIES
COLDER THAN TUESDAY. WITH THE SECOND FRONT WEDNESDAY NIGHT...THE
BIGGER CONCERN WILL BE WIND CHILLS. THE 850 MB TEMPS PLUMMET TO -17
TO -24C ACRS MOST OF THE CWFA. WITH STILL DECENT WINDS OF 30-40 KTS
AT 850 MB AND CAA...SHUD SEE GUSTY WINDS LINGERING OVERNIGHT IN THE
MTNS AND A LIGHT WIND ACRS THE PIEDMONT. THIS COUPLED WITH LIKELY
RECORD LOW TEMPS THURSDAY MORNING WILL RESULT IN SOLID WIND CHILL
ADV CRITERIA ACRS NEARLY THE ENTIRE CWFA...AND WIND CHILL WARNING
ACRS ALL THE NC MTNS ABOVE 3500 FT. WILL HIGHLIGHT DANGEROUS WIND
CHILLS IN THE HWO. FOR THE DAILY RECORD LOWS FOR THURSDAY SEE
CLIMATE SECTION BELOW.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 255 AM MONDAY...ONLY A FEW CHANGES WERE MADE THE PREVIOUS FCST
AS GUIDANCE CONTINUES TO SHOW UNCERTAINTY WITH THE EVOLUTION OF THE
SRN STREAM SFC BNDRY AND DEGREE/PLACEMENT OF SFC CYCLOGENESIS. THERE
SHOULD BE A GOOD AMOUNT OF GOM MOISTURE FLUX AFT THU BUT AGAIN...AN
AGREEABLE AREA OF LIKELY PRECIP REMAINS TO BE WORKED OUT.
WITH A VERY COLD START TO THE DAY THU AND A CA HIGH CENTER WORKING
ACROSS TN...MAX TEMPS WILL RECOVER ONLY NOMINALLY EVEN WITH VERY
GOOD INSOL. RECORD LOW MAXES ARE STILL FCST/D BY A FEW DEGREES. THU
NIGHT AND FRI WILL REMAIN QUITE COLD AS THE SFC HIGH SHIFTS EAST
ACROSS SRN VA AND ENABLES GOOD RAD COOLING AND A SLOWLY VEERING FLOW.
THUS...MINS AND MAXES WILL AGAIN APPROACH AND POSSIBLY BREAK RECORD
LEVELS. SEE THE CLIMATE SECTION OF THIS AFD FOR THE ACTUAL RECORD
VALUES. VERY COLD WIND CHILLS WILL DEVELOP THU NIGHT ACROSS THE
FCST AREA...WITH THE NC MTNS LIKELY REACHING WARNING/ADV CRITERIA
THROUGH DAYBREAK.
THE PATTERN REMAINS ACTIVE FRI THROUGH THE WEEKEND. HOWEVER...MORE
UNCERTAINTY ARISES...WITH THE OP MODELS CONTINUING TO SHOW DISPARATE
HANDLINGS WRT THE SRN BNDRY AND INTERACTIONS WITH ULVL S/W ENERGY.
THE LATEST TREND HAS BEEN FOR A SLOWER ADVANCEMENT EAST WITH
MEASURABLE PRECIP FRI AS A STUBBORN CA HIGH PERSISTS OVER THE
CAROLINAS. THE ECMWF HAS MORE RIDGING ALOFT AND THIS KEEPS IT/S SFC
BNDRY MORE NORTH AND WEST THAN THE GFS THROUGH THE PERIOD. SO...POPS
WERE ADJ DOWN A LITTLE ACCOUNT FOR HIGHER UNCERTAINTY MAINLY ACROSS
THE SRN ZONES. PRECIP SHOULD BE MAINLY DIURNAL RAIN/SNOW...WITH SOME
LOW SNOW ACCUMS POSSIBLE OUTSIDE THE MTNS FRI NIGHT AND AGAIN
NON/MTN -SNSH POSSIBLE SAT NIGHT OVER THE NRN ZONES. MAX TEMPS
SHOULD WARM 8-10 DEGREES BOTH SAT AND SUN...YET STILL A COUPLE
DEGREES BELOW NORMAL SUN AFTERNOON.
&&
.AVIATION /16Z MONDAY THROUGH FRIDAY/...
AT KCLT...VFR CONDITIONS WILL CONTINUE THROUGH THIS AFTERNOON WITH
WINDS FROM THE ESE TO SE. BASED ON LATEST GUIDANCE AND FORECAST
SOUNDINGS...FZRA/SN/IP SHOULD DEVELOP AROUND 21Z...WITH FZRA
INCREASING THROUGH THE EVENING. PRECIP RATES SHOULD DROP OFF SHARPLY
BETWEEN 06Z TO 09Z. VSBY AND CIGS SHOULD DECREASE TO IFR THIS
EVENING AS THE PRECIP RATES INCREASE. TEMPERATURES DURING THE
PRECIPITATION SHOULD LINGER JUST BELOW FREEZING. IT APPEARS THAT BY
12Z THE TERMINAL WILL RECEIVE AROUND TWO TENTHS OF AN INCH OF SLEET
WITH BETWEEN TWO TO THREE TENTHS OF AN INCH OF FZRA. DEICING WILL
BECOME A BIG ISSUE EARLY TUESDAY. WINDS ARE FORECAST TO BECOME NORTH
BY 9Z.
ELSEWHERE...MODELS ARE IN GOOD AGREEMENT WITH THE PLACEMENT AND
TIMING OF THE MAJOR FEATURES OF THE NEAR TERM FORECAST. IT APPEARS
THAT PRECIP WILL BEGIN AT KAVL AROUND 17Z TO 18Z...THEN REACHING THE
WESTERN CAROLINA TERMINALS BETWEEN 21Z TO 22Z. KAVL WILL HAVE THE
COLDER THERMAL PROFILES...KEEPING A MIX OF SN/IP THROUGH THIS
AFTERNOON...THEN MIXING WITH FZRA THROUGH THE EVENING HOURS. VIS AND
CIGS WILL FALL TO MVFR BY 21Z...REACHING LIFR BY 4Z. EAST OF THE
MTNS...PRECIP WILL FAVOR FZRA...WITH PERIODS OF SN/IP AT KHKY...AND
RA AT KAND. ALL SITES WILL SEE IFR TO LIFR CONDITIONS BY THIS
EVENING. WINDS WILL VEER FROM ENE THIS MORNING TO SOUTHEAST BY THIS
AFTERNOON...KAVL FAVORING A SE DIRECTION. KAVL WINDS ARE FORECAST TO
BECOME NORTH BY 9Z.
OUTLOOK...CONDITIONS WILL IMPROVE TO VFR BY WEDNESDAY AND THEN
CONTINUE THURSDAY...BUT BECOMING VERY COLD.
CONFIDENCE TABLE...
13-19Z 19-01Z 01-07Z 07-12Z
KCLT HIGH 95% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL MED 74% HIGH 100% HIGH 100% HIGH 100%
KHKY MED 77% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY
EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS
ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.CLIMATE...
RECORD MINIMUM TEMPERATURES FOR THURSDAY...FEBRUARY 19TH...
GSP 9 1958
CLT 8 1958
AVL 7 1958
RECORD LOW MAXIMUM TEMPERATURES FOR THURSDAY...FEBRUARY 19TH...
GSP 30 1900
CLT 34 1958
AVL 25 1958
RECORD MINIMUM TEMPERATURES FOR FRIDAY...FEBRUARY 20TH...
GSP 13 1903
CLT 13 1896
AVL 10 1979
RECORD LOW MAXIMUM TEMPERATURES FOR FRIDAY...FEBRUARY 20TH...
GSP 34 1947
CLT 32 1947
AVL 26 1979
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...WINTER STORM WARNING UNTIL 7 AM EST TUESDAY FOR GAZ010-017.
WINTER WEATHER ADVISORY UNTIL 7 AM EST TUESDAY FOR GAZ018.
NC...WINTER STORM WARNING UNTIL 7 AM EST TUESDAY FOR NCZ033-048>053-
058-059-062>065-501-503-505-507-509.
WINTER STORM WARNING UNTIL 7 AM EST TUESDAY FOR NCZ035>037-056-
057-068>072-082-502-504-506-508-510.
SC...WINTER STORM WARNING UNTIL 7 AM EST TUESDAY FOR SCZ001>003.
WINTER STORM WARNING UNTIL 7 AM EST TUESDAY FOR SCZ005>009.
WINTER WEATHER ADVISORY UNTIL 7 AM EST TUESDAY FOR SCZ004-010-
012>014.
&&
$$
SYNOPSIS...SBK
NEAR TERM...HG
SHORT TERM...ARK
LONG TERM...SBK
AVIATION...HG/NED
CLIMATE...
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
932 AM CST MON FEB 16 2015
.AVIATION...
THE DFW AREA TAFS REMAIN UNCHANGED FROM THEIR 12Z ISSUANCE.
UPDATED THE WACO (KACT) TAF TO INCLUDE A TEMPO GROUP FOR FREEZING
RAIN FROM 16 TO 17Z. THE 1530Z TEMPERATURE AT WACO WAS 34 DEGREES
WITH ONGOING LIGHT RAIN OVER MUCH OF MCLENNAN COUNTY. TEMPERATURES
ARE EXPECTED TO FALL TO 30 TO 32 DEGREES BEFORE DRIER AIR MOVES IN
AND PRECIPITATION DISSIPATES LATER THIS MORNING.
CAVANAUGH
.../PREVIOUS AVIATION DISCUSSION/...
BAND OF LIGHT TO MODERATE RAIN HAS PUSHED EAST OF TAF SITES AND
EXPECT JUST SOME LIGHT DRIZZLE TO BE THE PRIMARY PRECIPITATE THIS
MORNING. WHILE TEMPERATURES AT AFW/FTW/DFW ARE NOW 33...ANY
DRIZZLE THAT DOES FALL WOULD HAVE THE POTENTIAL TO FREEZE ON
CONTACT TO AIRPLANE SURFACES. THAT IS BECAUSE DRIZZLE DROPLETS
WOULD LIKELY BE SUPER-COOLED...SO EVEN IF AIR TEMPERATURE STAYS
AT 33...LIGHT ICING MAY BE AN ISSUE THIS MORNING THAT REQUIRES
SOME DEICING OPERATIONS. SINCE TEMPERATURES ARE EXPECTED TO REMAIN
VERY NEAR FREEZING...AND DRIZZLE WILL BE VERY LIGHT...WE DO NOT
EXPECT THE IMPACTS WITH FREEZING DRIZZLE TO BE ON THE ORDER OF
WHAT OCCURRED AT DFW A WEEK AND A HALF AGO. THE THREAT FOR DRIZZLE
AND/OR FREEZING DRIZZLE IS EXPECTED TO END AT THE LATEST BY
16Z/10AM AT METROPLEX TAF SITES WITH BAND OF PRECIP SHIFTING
SOUTHEAST. WACO WILL LIKELY CONTEND WITH LIGHT RAIN IN THE AREA
THROUGH EARLY AFTERNOON BUT TEMPS WILL BE TOO WARM THERE FOR ANY
IMPACTS.
OTHERWISE MVFR CIGS WILL PREVAIL THIS MORNING AND INTO EARLY
AFTERNOON AT METROPLEX TAF SITES. AT WACO IFR IS EXPECTED FOR A
FEW MORE HOURS...BEFORE THEY LIFT TO MVFR AS THE FRONTAL LAYER
DEEPENS. CIGS SHOULD LIFT FURTHER TO VFR BY MID-LATE AFTERNOON.
EXPECT OVERCAST SKIES TONIGHT NEAR FL100...WITH VIRGA LIKELY FROM
SNOW FALLING ALOFT. THE LOW LEVELS LOOK TOO DRY FOR SNOW TO REACH
THE SURFACE AT TAF SITES...ALTHOUGH A STRAY SNOWFLAKE WOULD BE
POSSIBLE. WILL NOT MENTION THIS POSSIBILITY IN TAFS. VFR WILL
PREVAIL OVERNIGHT AND TOMORROW MORNING WITH LIGHT N/NW WINDS.
TR.92
&&
.PREV DISCUSSION... /ISSUED 353 AM CST MON FEB 16 2015/
COLD FRONT CONTINUES TO MOVE THROUGH NORTH TEXAS THIS MORNING AND
IS CURRENTLY ALONG A LINE FROM NEAR TYLER TO CORSICANA TO KILLEEN.
TEMPERATURES HAVE FALLEN INTO THE 30S BEHIND THE FRONT WITH GUSTY
NORTHWEST WINDS. THE FREEZING LINE IS LOCATED FROM GAINESVILLE TO
MINERAL WELLS TO COMANCHE AND WILL SLOWLY ADVANCE EASTWARD THROUGH
THE EARLY MORNING HOURS. IT SHOULD BE LOCATED ACROSS THE NORTHWEST
PARTS OF THE METROPLEX BY SUNRISE. A LARGE AREA OF PRECIPITATION
IS ONGOING ALONG THE FRONTAL BOUNDARY ITSELF AND THIS IS PRIMARILY
RAIN. THE ONLY EXCEPTION HAS BEEN SOME SLEET OR SMALL HAIL WITH
THE STRONGER CONVECTIVE ELEMENTS BEHIND THE FRONT.
THE LEAD SHORTWAVE IN THE TROUGH OVER THE ROCKIES IS IN THE
PROCESS OF EJECTING EASTWARD ACROSS THE PLAINS THIS MORNING. THIS
WILL ALLOW THE COLD FRONT TO CONTINUE RACING SOUTHWARD
TODAY...TAKING THE PRECIPITATION WITH IT. MOST OF THE
PRECIPITATION WILL BE OUT OF THE AREA BY THE AFTERNOON HOURS. OUR
MAIN CONCERN IN THE IMMEDIATE SHORT TERM IS THE POTENTIAL FOR SOME
FREEZING DRIZZLE ACROSS THE NORTHWEST COUNTIES. LATEST HIGH
RESOLUTION GUIDANCE INDICATES AN AREA OF ISENTROPIC ASCENT IN THE
700-500MB LAYER THROUGH EARLY MORNING. THIS IS ASSOCIATED WITH THE
SHORTWAVE TROUGH MOVING THROUGH THE SOUTHERN PLAINS AND THE LIFT
ITSELF WILL LIKELY ONLY PERSIST FOR A FEW HOURS. RUC SOUNDINGS
ACROSS THE WESTERN COUNTIES SHOW SATURATED CONDITIONS DURING THIS
TIME ALTHOUGH DRYING WILL BEGIN TO OCCUR QUICKLY AFTER 12Z. WITH
WEAK ASCENT THROUGH A SATURATED LAYER...AREAS OF DRIZZLE ARE
LIKELY TO OCCUR. TEMPERATURES ARE ALREADY A FEW DEGREES COOLER
THAN PREVIOUSLY ANTICIPATED AND ARE LIKELY TO REMAIN 28 TO 30
DEGREES THROUGH 14Z ACROSS THE NORTHWEST PART OF THE CWA. THIS
SHOULD BE SUFFICIENT FOR SOME LIGHT ICING TO OCCUR MAINLY ON
BRIDGES OVER THE NEXT SEVERAL HOURS. WE HAVE ALREADY RECEIVED ONE
REPORT OF MINOR ICING ON BRIDGES IN MONTAGUE COUNTY. WE WENT AHEAD
AND ISSUED A FREEZING RAIN ADVISORY THROUGH MID MORNING MAINLY FOR
THESE MINOR ICE ACCUMULATIONS ON BRIDGES. MAIN ROADS SHOULD
CONTINUE TO BE FINE AS GROUND TEMPERATURES HAVE BEEN VERY WARM AND
ARE LIKELY TO MELT ANY LIGHT PRECIPITATION.
WITH PRECIPITATION COMING TO AN END LATER TODAY...THERE WILL BE
SOME CLEARING TO THE WEST. IT WILL BE A COLD DAY WITH HIGHS IN THE
30S AND 40S AREAWIDE AND GUSTY NORTHWEST WINDS KEEPING WIND CHILLS
IN THE 20S THROUGHOUT THE DAY. THE MAIN TROUGH OVER THE ROCKIES
WILL ACTUALLY CROSS THE AREA LATE TONIGHT INTO TUESDAY MORNING.
SKIES ARE EXPECTED TO BECOME CLOUDY AGAIN TONIGHT AND FORCING FROM
THIS TROUGH WILL ACTUALLY BE STRONGER...HOWEVER SIGNIFICANT DRYING
WILL HAVE ALREADY OCCURRED BELOW 700MB. IT WILL BE TOUGH TO GET ANY
ADDITIONAL PRECIPITATION LATE TONIGHT INTO EARLY TUESDAY BUT GIVEN
THE STRONG ASCENT WE WILL KEEP SOME 20 POPS FOR LIGHT SNOW MAINLY
ACROSS THE WESTERN COUNTIES. FLURRIES WILL BE POSSIBLE FARTHER TO
THE EAST INTO EARLY TUESDAY MORNING. NO SNOW ACCUMULATIONS ARE
EXPECTED.
TEMPERATURES ARE EXPECTED TO WARM THROUGH THE END OF THE WEEK WITH
HIGHS AGAIN NEAR 70 BY FRIDAY. ANOTHER STRONG SHORTWAVE WILL MOVE
INTO THE WESTERN U.S. BY THIS TIME AND LOW LEVEL MOISTURE WILL
BEGIN TO BE PULLED NORTHWARD IN RESPONSE. ANOTHER STRONG COLD
FRONT IS EXPECTED TO MOVE THROUGH NEXT WEEKEND...MOST LIKELY ON
SATURDAY WITH SCATTERED SHOWERS POSSIBLE LATE FRIDAY INTO EARLY
SUNDAY.
DUNN
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 39 30 48 34 55 / 40 10 10 5 0
WACO, TX 41 30 48 32 60 / 50 10 10 5 0
PARIS, TX 36 26 46 29 48 / 70 10 10 5 0
DENTON, TX 37 29 48 30 54 / 30 10 10 5 0
MCKINNEY, TX 38 28 48 30 52 / 50 10 10 5 0
DALLAS, TX 41 31 48 35 55 / 50 10 10 5 0
TERRELL, TX 37 29 47 31 54 / 60 10 10 5 0
CORSICANA, TX 40 29 47 33 58 / 70 10 10 5 0
TEMPLE, TX 41 31 48 32 61 / 50 10 10 5 0
MINERAL WELLS, TX 40 29 49 31 58 / 30 20 20 5 0
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
538 AM CST MON FEB 16 2015
.AVIATION...
BAND OF LIGHT TO MODERATE RAIN HAS PUSHED EAST OF TAF SITES AND
EXPECT JUST SOME LIGHT DRIZZLE TO BE THE PRIMARY PRECIPITATE THIS
MORNING. WHILE TEMPERATURES AT AFW/FTW/DFW ARE NOW 33...ANY
DRIZZLE THAT DOES FALL WOULD HAVE THE POTENTIAL TO FREEZE ON
CONTACT TO AIRPLANE SURFACES. THAT IS BECAUSE DRIZZLE DROPLETS
WOULD LIKELY BE SUPER-COOLED...SO EVEN IF AIR TEMPERATURE STAYS
AT 33...LIGHT ICING MAY BE AN ISSUE THIS MORNING THAT REQUIRES
SOME DEICING OPERATIONS. SINCE TEMPERATURES ARE EXPECTED TO REMAIN
VERY NEAR FREEZING...AND DRIZZLE WILL BE VERY LIGHT...WE DO NOT
EXPECT THE IMPACTS WITH FREEZING DRIZZLE TO BE ON THE ORDER OF
WHAT OCCURRED AT DFW A WEEK AND A HALF AGO. THE THREAT FOR DRIZZLE
AND/OR FREEZING DRIZZLE IS EXPECTED TO END AT THE LATEST BY
16Z/10AM AT METROPLEX TAF SITES WITH BAND OF PRECIP SHIFTING
SOUTHEAST. WACO WILL LIKELY CONTEND WITH LIGHT RAIN IN THE AREA
THROUGH EARLY AFTERNOON BUT TEMPS WILL BE TOO WARM THERE FOR ANY
IMPACTS.
OTHERWISE MVFR CIGS WILL PREVAIL THIS MORNING AND INTO EARLY
AFTERNOON AT METROPLEX TAF SITES. AT WACO IFR IS EXPECTED FOR A
FEW MORE HOURS...BEFORE THEY LIFT TO MVFR AS THE FRONTAL LAYER
DEEPENS. CIGS SHOULD LIFT FURTHER TO VFR BY MID-LATE AFTERNOON.
EXPECT OVERCAST SKIES TONIGHT NEAR FL100...WITH VIRGA LIKELY FROM
SNOW FALLING ALOFT. THE LOW LEVELS LOOK TOO DRY FOR SNOW TO REACH
THE SURFACE AT TAF SITES...ALTHOUGH A STRAY SNOWFLAKE WOULD BE
POSSIBLE. WILL NOT MENTION THIS POSSIBILITY IN TAFS. VFR WILL
PREVAIL OVERNIGHT AND TOMORROW MORNING WITH LIGHT N/NW WINDS.
TR.92
&&
.PREV DISCUSSION... /ISSUED 353 AM CST MON FEB 16 2015/
COLD FRONT CONTINUES TO MOVE THROUGH NORTH TEXAS THIS MORNING AND
IS CURRENTLY ALONG A LINE FROM NEAR TYLER TO CORSICANA TO KILLEEN.
TEMPERATURES HAVE FALLEN INTO THE 30S BEHIND THE FRONT WITH GUSTY
NORTHWEST WINDS. THE FREEZING LINE IS LOCATED FROM GAINESVILLE TO
MINERAL WELLS TO COMANCHE AND WILL SLOWLY ADVANCE EASTWARD THROUGH
THE EARLY MORNING HOURS. IT SHOULD BE LOCATED ACROSS THE NORTHWEST
PARTS OF THE METROPLEX BY SUNRISE. A LARGE AREA OF PRECIPITATION
IS ONGOING ALONG THE FRONTAL BOUNDARY ITSELF AND THIS IS PRIMARILY
RAIN. THE ONLY EXCEPTION HAS BEEN SOME SLEET OR SMALL HAIL WITH
THE STRONGER CONVECTIVE ELEMENTS BEHIND THE FRONT.
THE LEAD SHORTWAVE IN THE TROUGH OVER THE ROCKIES IS IN THE
PROCESS OF EJECTING EASTWARD ACROSS THE PLAINS THIS MORNING. THIS
WILL ALLOW THE COLD FRONT TO CONTINUE RACING SOUTHWARD
TODAY...TAKING THE PRECIPITATION WITH IT. MOST OF THE
PRECIPITATION WILL BE OUT OF THE AREA BY THE AFTERNOON HOURS. OUR
MAIN CONCERN IN THE IMMEDIATE SHORT TERM IS THE POTENTIAL FOR SOME
FREEZING DRIZZLE ACROSS THE NORTHWEST COUNTIES. LATEST HIGH
RESOLUTION GUIDANCE INDICATES AN AREA OF ISENTROPIC ASCENT IN THE
700-500MB LAYER THROUGH EARLY MORNING. THIS IS ASSOCIATED WITH THE
SHORTWAVE TROUGH MOVING THROUGH THE SOUTHERN PLAINS AND THE LIFT
ITSELF WILL LIKELY ONLY PERSIST FOR A FEW HOURS. RUC SOUNDINGS
ACROSS THE WESTERN COUNTIES SHOW SATURATED CONDITIONS DURING THIS
TIME ALTHOUGH DRYING WILL BEGIN TO OCCUR QUICKLY AFTER 12Z. WITH
WEAK ASCENT THROUGH A SATURATED LAYER...AREAS OF DRIZZLE ARE
LIKELY TO OCCUR. TEMPERATURES ARE ALREADY A FEW DEGREES COOLER
THAN PREVIOUSLY ANTICIPATED AND ARE LIKELY TO REMAIN 28 TO 30
DEGREES THROUGH 14Z ACROSS THE NORTHWEST PART OF THE CWA. THIS
SHOULD BE SUFFICIENT FOR SOME LIGHT ICING TO OCCUR MAINLY ON
BRIDGES OVER THE NEXT SEVERAL HOURS. WE HAVE ALREADY RECEIVED ONE
REPORT OF MINOR ICING ON BRIDGES IN MONTAGUE COUNTY. WE WENT AHEAD
AND ISSUED A FREEZING RAIN ADVISORY THROUGH MID MORNING MAINLY FOR
THESE MINOR ICE ACCUMULATIONS ON BRIDGES. MAIN ROADS SHOULD
CONTINUE TO BE FINE AS GROUND TEMPERATURES HAVE BEEN VERY WARM AND
ARE LIKELY TO MELT ANY LIGHT PRECIPITATION.
WITH PRECIPITATION COMING TO AN END LATER TODAY...THERE WILL BE
SOME CLEARING TO THE WEST. IT WILL BE A COLD DAY WITH HIGHS IN THE
30S AND 40S AREAWIDE AND GUSTY NORTHWEST WINDS KEEPING WIND CHILLS
IN THE 20S THROUGHOUT THE DAY. THE MAIN TROUGH OVER THE ROCKIES
WILL ACTUALLY CROSS THE AREA LATE TONIGHT INTO TUESDAY MORNING.
SKIES ARE EXPECTED TO BECOME CLOUDY AGAIN TONIGHT AND FORCING FROM
THIS TROUGH WILL ACTUALLY BE STRONGER...HOWEVER SIGNIFICANT DRYING
WILL HAVE ALREADY OCCURRED BELOW 700MB. IT WILL BE TOUGH TO GET ANY
ADDITIONAL PRECIPITATION LATE TONIGHT INTO EARLY TUESDAY BUT GIVEN
THE STRONG ASCENT WE WILL KEEP SOME 20 POPS FOR LIGHT SNOW MAINLY
ACROSS THE WESTERN COUNTIES. FLURRIES WILL BE POSSIBLE FARTHER TO
THE EAST INTO EARLY TUESDAY MORNING. NO SNOW ACCUMULATIONS ARE
EXPECTED.
TEMPERATURES ARE EXPECTED TO WARM THROUGH THE END OF THE WEEK WITH
HIGHS AGAIN NEAR 70 BY FRIDAY. ANOTHER STRONG SHORTWAVE WILL MOVE
INTO THE WESTERN U.S. BY THIS TIME AND LOW LEVEL MOISTURE WILL
BEGIN TO BE PULLED NORTHWARD IN RESPONSE. ANOTHER STRONG COLD
FRONT IS EXPECTED TO MOVE THROUGH NEXT WEEKEND...MOST LIKELY ON
SATURDAY WITH SCATTERED SHOWERS POSSIBLE LATE FRIDAY INTO EARLY
SUNDAY.
DUNN
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 40 30 48 34 55 / 40 10 10 5 0
WACO, TX 41 30 48 32 60 / 50 10 10 5 0
PARIS, TX 36 26 46 29 48 / 70 10 10 5 0
DENTON, TX 37 29 48 30 54 / 30 10 10 5 0
MCKINNEY, TX 38 28 48 30 52 / 50 10 10 5 0
DALLAS, TX 41 31 48 35 55 / 50 10 10 5 0
TERRELL, TX 37 29 47 31 54 / 60 10 10 5 0
CORSICANA, TX 40 29 47 33 58 / 70 10 10 5 0
TEMPLE, TX 41 31 48 32 61 / 50 10 10 5 0
MINERAL WELLS, TX 40 29 49 31 58 / 30 20 20 5 0
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
FREEZING RAIN ADVISORY UNTIL 10 AM CST THIS MORNING FOR TXZ091-
092-100>102-115-116-129.
&&
$$
/
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
531 AM CST MON FEB 16 2015
.DISCUSSION...
SEE AVIATION FOR 12Z TAF ISSUANCE.
&&
.AVIATION...
COLD FRONT CURRENTLY PUSHING SOUTHWARDS QUICKER THAN EXPECTED.
FRONT IS APPROACHING CALDWELL AND NOT THAT FAR AWAY FROM COLLEGE
STATION AT THIS TIME. HAVE GONE AHEAD AND BUMPED UP FRONTAL
PASSAGE TIMING IN TAFS BY A COUPLE OF HOURS. THE HRRR HAS
PERFORMED POORLY THIS MORNING WHILE THE TEXAS TECH WRF INITIALIZED
WELL AND IS BRINGING A THIN LINE OF SHOWERS THROUGH THE AREA WITH
THE FRONT. FORECAST SOUNDINGS SHOWING THE POSSIBILITY OF THUNDER
BUT CURRENT OBS SHOWING MOST OF THE THUNDER REMAINING NORTH OF THE
FRONT. SO FOR NOW HAVE LEFT MENTION OF THUNDER OUT OF TAFS. MOST
SITES SHOULD REMAIN BORDERLINE IFR TO MVFR TODAY AFTER THE FRONTAL
PASSAGE. 23
&&
.PREV DISCUSSION... /ISSUED 343 AM CST MON FEB 16 2015/
DISCUSSION...
AT 3 AM...A STRONG COLD FRONT EXTENDED FROM NEAR SULPHUR SPRINGS
TO CORSICANA TO BROWNWOOD. THE FRONT WILL MAKE STEADY PROGRESS
SOUTH AND SHOULD REACH COLLEGE STATION BETWEEN 6-7 AM...HOUSTON
BETWEEN 10-11 AM AND CLEAR THE COAST BETWEEN NOON AND 1 PM. HIGH
TEMPERATURES WILL OCCUR THIS MORNING WITH A QUICK 15 TO 20 DEGREE
TEMPERATURE DROP BEHIND THE FRONT. PW VALUES WILL INCREASE TO
BETWEEN 1.3 AND 1.5 INCHES...BUT JET DYNAMICS NOT TOO IMPRESSIVE
SO OTHER THAN STRONG LOW LEVEL CONVERGENCE...NOT TOO MANY OTHER
PARAMETERS ARE IN PLACE TO GENERATE PRECIP. THAT SAID...THE
CONVERGENCE SHOULD BE ENOUGH TO GENERATE A LINE OF SHOWERS AND
ISOLATED THUNDERSTORMS WITH THE FRONT BUT THE QUICK MOVEMENT OF
THE FRONT WILL YIELD MEAGER RAINFALL AMOUNTS. WINDS WILL INCREASE
RAPIDLY BEHIND THE FRONT AS WELL...BUT SUSTAINED WIND SPEEDS WILL
REMAIN BELOW ADVISORY CRITERIA EXCEPT ALONG THE IMMEDIATE COAST. A
WIND ADVISORY WILL LIKELY BE ISSUED FOR THE COASTAL COUNTIES LATE
THIS AFTERNOON AS SUSTAINED WINDS WILL LIKELY REACH THE 25 MPH
THRESHOLD. FCST SOUNDINGS FOR TONIGHT SHOW A SATURATED LAYER TO
AROUND 850 MB WITH DRY AIR ABOVE THIS LAYER. THIS TYPE OF SOUNDING
GENERALLY INDICATES SOME POTENTIAL FOR VERY LIGHT RAIN OR DRIZZLE
SO WILL CARRY LOW END RAIN CHANCES THROUGH THE OVERNIGHT HOURS.
THE AIR MASS BEHIND THE FRONT IS VERY COLD AND WITH LOWER 20S
OVER OKLAHOMA FILTERING TO THE SOUTH. FEEL MIN TEMPS TONIGHT WILL
BE ON THE COLD SIDE. TRENDED A BIT COLDER THAN GUIDANCE AND A
LIGHT FREEZE WILL BE POSSIBLE NORTH OF A BRENHAM TO CONROE TO
CLEVELAND LINE. LINGERING CLOUD COVER WILL PREVAIL FOR MOST OF
TUESDAY WITH SOME THINNING OF THE CLOUD SHIELD DURING THE
AFTERNOON. HIGH PRESSURE WILL SETTLE OVER THE STATE TUES NIGHT AND
WEDNESDAY. THIS FEATURE WILL BRING CLEAR SKIES AND COLD
TEMPERATURES. A WARM UP BEGINS ON THURSDAY WITH MUCH WARMER TEMPS
EXPECTED FRI-SUN AS THE SURFACE HIGH SHIFTS EAST AND ONSHORE WINDS
RETURN. MOISTURE LEVELS ALSO INCREASE AS PW VALUES RISE TO 1.30
INCHES. FCST SOUNDINGS STILL SHOW A LARGE AMOUNT OF DRY AIR ABOVE
700 MB SO WILL STAY WITH VERY LOW END RAIN CHANCES FOR NEXT
WEEKEND. 43
MARINE...
SOUTHERLY WINDS HAVE REMAINED ABOVE SCEC CRITERIA IN THE OFFSHORE
ZONES THIS MORNING THANKS TO A RELATIVELY TIGHT PRESSURE GRADIENT. A
COLD FRONT IS PROGGED TO PUSH OFF THE COAST THIS AFTERNOON AROUND
1PM. STRONG NORTHWEST TO NORTH WINDS CAN BE EXPECTED IN ITS WAKE
WITH ADVISORY CRITERIA EASILY BEING MET. SOME GUSTS COULD APPROACH
GALE FORCE. WINDS WILL THEN FALL BELOW SCA CRITERIA TUESDAY MORNING
AROUND SUNRISE AS HIGH PRESSURE MOVES IN FROM THE NORTH. 23
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 61 32 50 34 59 / 60 20 10 10 0
HOUSTON (IAH) 68 38 50 36 60 / 60 20 20 10 0
GALVESTON (GLS) 68 43 52 43 56 / 70 20 20 10 0
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO MIDNIGHT CST
TONIGHT FOR THE FOLLOWING ZONES: GALVESTON BAY...MATAGORDA
BAY.
SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO 6 AM CST
TUESDAY 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.
SMALL CRAFT SHOULD EXERCISE CAUTION 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...43
AVIATION/MARINE...23
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
249 PM EST MON FEB 16 2015
.SYNOPSIS...
LOW PRESSURE WILL BE NEAR THE FORECAST AREA TONIGHT AND OFF THE
COAST TUESDAY. WINTER-TYPE PRECIPITATION WILL OCCUR ACROSS THE
NORTHERN PORTIONS OF SC BECAUSE OF THE COLDER AIR MASS IN PLACE
AHEAD OF THE SYSTEM. WELL BELOW NORMAL TEMPERATURES EXPECTED
THROUGH THE WEEK UNDER THE INFLUENCE OF AN ARCTIC AIR MASS.
&&
.NEAR TERM /THROUGH TONIGHT/...
BROAD UPPER LEVEL TROUGH IN THE MIDWEST WILL CONTINUE SHIFTING
EAST WITH SOUTHWESTERLY FLOW INCREASING ACROSS THE CAROLINAS. 19Z
SURFACE ANALYSIS SHOWS HIGH PRESSURE ALONG THE NC/VA COAST RIDGING
INTO THE FORECAST AREA. MEANWHILE...LOW PRESSURE OVER THE TN/MS
VALLEY REGION IS SHIFTING NORTHEAST TOWARD THE REGION ACCOMPANIED
BY A LARGE SWATH OF PRECIPITATION. REGIONAL RADAR COMPOSITE THIS
AFTERNOON SHOWS LIGHT PRECIPITATION BEGINNING TO MOVE INTO THE
WESTERN MIDLANDS AND CSRA WHICH IS SUPPORTED BY WARM ADVECTION AND
ISENTROPIC LIFT AHEAD OF THE LOW. WE HAVE RECEIVED A FEW REPORTS
OF LIGHT SLEET IN NEWBERRY COUNTY. DRY AIR MASS IS MOISTENING FROM
THE SOUTH THIS AFTERNOON WITH DEWPOINTS ON THE RISE. DEWPOINTS IN
THE PEE DEE AND NORTHERN MIDLANDS REMAIN VERY DRY...GENERALLY IN
THE SINGLE DIGITS.
LATEST MODEL GUIDANCE STILL SUPPORTS LOW TRACK ACROSS THE WESTERN
PART OF THE FORECAST AREA TONIGHT. HRRR APPEARS TO BE TRACKING
WELL WITH CURRENT RADAR TRENDS AND IS MUCH FASTER WITH THE PRECIP
REACHING THE AREA THAN THE 12Z NAM. THIS AGREES PRETTY WELL WITH
TIMING IN CURRENT FORECAST SO HAVE NOT MADE ANY TIMING
ADJUSTMENTS. HIGH RESOLUTION MODELS LIKE THE RAP AND HRRR ARE
WARMER THAN SOME OF THE OTHER GUIDANCE BUT BELIEVE THIS MAY BE
A LITTLE OVERDONE AS THESE MODELS HAVE BEEN TOO HIGH WITH THE
DEWPOINTS SO FAR TODAY. PRECIPITABLE WATER INCREASES TO NEAR 1.3
INCHES BY 06Z TUESDAY AND ISENTROPIC LIFT IS ALSO VERY STRONG
DURING THIS TIME SO HAVE HIGHEST POPS 03Z TO 09Z. MODEL SOUNDINGS
INDICATE DEEP WARM NOSE ACROSS THE REGION TONIGHT AS VERY STRONG
LOW LEVEL WARM ADVECTION DEVELOPS. SOUTHWEST 850MB JETMAX GREATER
THAN 60KTS. SHALLOW FREEZING LAYER LIKELY NORTH OF CAE. LARGE
TEMPERATURE GRADIENT EXPECTED WITH FREEZING TEMPS NORTH OF CAE
TONIGHT TO POSSIBLY LOW 50S IN THE CSRA AS WARM ADVECTION
INCREASES AND DEEPENS. TEMPERATURES EXPECTED TO RISE OVERNIGHT IN
THE SOUTHERN AREAS.
WITH DEEP WARM NOSE AND SHALLOW FREEZING LAYER...STILL EXPECT
FREEZING RAIN IN THE NORTH MIDLANDS...PIEDMONT AND PEE DEE
OVERNIGHT. ICING ESTIMATE IN MOST AREAS LESS THAN A TENTH OF AN
INCH WITH THE HIGHEST AMOUNTS EXPECTED IN NORTHERN LANCASTER
COUNTY OF UP TO TWO TENTHS OF AN INCH. FREEZING RAIN ADVISORY
REMAINS IN EFFECT.
&&
.SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...
BOTH THE NAM AND GFS SHOW THE CENTER OF THE LOW ALONG THE VA/NC
COAST BY 12Z TUESDAY MORNING WITH MOISTURE DECREASING ACROSS THE
AREA AS THE LOW CONTINUES TO SHIFT FURTHER NORTHEAST THROUGH THE
DAY ON TUESDAY. SHORTWAVE ENERGY ASSOCIATED WITH THE TROUGH WILL
PROMOTE A SLIGHT CHANCE OF LIGHT PRECIP TUESDAY MORNING AS IT
CROSSES THE REGION. MODEL SOUNDINGS SUGGEST MOISTURE BECOMING
QUITE SHALLOW EARLY TUESDAY...KEPT LOW CHANCE POPS AND
PRECIPITATION MAINLY LIQUID RAIN ALTHOUGH LIGHT FREEZING
RAIN/DRIZZLE POSSIBLE IN THE NORTH MIDLANDS THROUGH ABOUT 15Z.
MODELS CONTINUE TO HINT AT A SLIGHT CHANCE OF LIGHT SNOW TUESDAY
NIGHT AS THE UPPER TROUGH SHIFTS EAST...ALTHOUGH MOISTURE APPEARS
VERY LIMITED...SO HAVE KEPT POPS LOW FOR NOW. HIGHS ON TUESDAY ARE
FORECAST IN THE LOWER 40S NORTH TO LOWER 50S SOUTH. DECREASING
CLOUDS TUESDAY NIGHT WILL PROMOTE LOWS IN THE UPPER 20S NORTH TO
LOWER 30S SOUTH.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
GENERALLY DRY INTO THE WEEKEND. HIGH PRESSURE WILL BUILD IN FROM THE
WEST WITH A REINFORCING SHOT OF ARCTIC AIR MOVING INTO THE AREA
THURSDAY AND FRIDAY. ANOTHER LOW PRESSURE SYSTEM DEVELOPING IN
THE SOUTHERN PLAINS BY EARLY SATURDAY WILL MOVE INTO THE TN VALLEY
BY SUNDAY AS MORE HIGH PRESSURE BUILDS IN FROM THE NORTH. AS A
RESULT...A COLD AIR DAMMING SCENARIO MAY OVER THE WEEKEND INTO
MONDAY. STILL LOTS OF QUESTIONS REGARDING TIMING AND PLACEMENT OF
THIS NEXT SYSTEM AND THE POSSIBILITY OF ANY WINTRY PRECIPITATION
EARLY NEXT WEEK. BUT WITH SOME MANY MODEL UNCERTAINTIES AT THIS
TIME...FOR NOW WILL KEEP PRECIPITATION ALL LIQUID SATURDAY INTO
MONDAY WITH CHANCE POPS. TEMPERATURES GENERALLY BELOW NORMAL THROUGH
THE EXTENDED PERIOD...WITH WELL BELOW NORMAL TEMPERATURES THURSDAY
AND FRIDAY. IN FACT...CURRENT MEX/MEN GUIDANCE HAS TEMPERATURES
ABOUT 20 TO 25 DEGREES BELOW NORMAL FOR CAE AND AGS THURSDAY AND
FRIDAY.
&&
.AVIATION /19Z MONDAY THROUGH SATURDAY/...
VFR CONDITIONS THROUGH EARLY EVENING THEN MVFR/IFR CONDITIONS FOR
THE REMAINDER OF THE PERIOD.
LOW PRESSURE OVER THE LOWER MISSISSIPPI VALLEY WILL MOVE EAST
ACROSS THE GULF COAST STATES TODAY AND CROSS THE FORECAST AREA
OVERNIGHT. CLOUDS CONTINUE TO THICKEN AND LOWER THIS AFTERNOON AS
MOISTURE INCREASES AHEAD OF THE APPROACHING LOW. GENERALLY EAST
WINDS GRADUALLY SHIFTING SOUTHEAST INTO EARLY EVENING...THEN
TURNING SOUTHERLY AND INCREASING TO AROUND 15-20 MPH WITH SOME
STRONGER GUSTS AS LOW PRESSURE MOVES INTO THE STATE. DRY AIR IN
PLACE WILL HELP TO EVAPORATE PRECIPITATION AS IT MOVES IN LATE
AFTERNOON BUT LIGHT RAIN SHOULD REACH TERMINALS AFTER 22Z-23Z AND
BECOME MORE WIDESPREAD BY 02Z-03Z AT AGS/DNL/CAE/CUB AND 04Z-06Z
AT OGB. CIGS AND VSBYS WILL DROP TO MVFR AT THE ONSET AND THEN
CIGS FALL TO IFR FOR A PERIOD OF TIME AS THE LOW CROSSES THE AREA
AND WINDS SHIFT TO THE WEST AND NORTHWEST AFTER THE LOW PASSES BY.
FREEZING RAIN IS NOT EXPECTED AT THE TERMINALS. CONDITIONS SLOWLY
IMPROVE AFTER 12Z FROM WEST TO EAST BUT CIGS REMAIN RESTRICTED.
EXTENDED AVIATION OUTLOOK...MVFR...POSSIBLE IFR...RESTRICTIONS
COULD LINGER INTO TUESDAY NIGHT. BREEZY CONDITIONS EXPECTED
WEDNESDAY.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...FREEZING RAIN ADVISORY UNTIL 7 AM EST TUESDAY FOR SCZ015-016-
020>022.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
1239 PM EST MON FEB 16 2015
.SYNOPSIS...
MOISTURE WILL INCREASE SLOWLY ACROSS THE REGION TODAY AHEAD OF
LOW PRESSURE TRACKING EASTWARD IN THE LOWER MISSISSIPPI RIVER
VALLEY. THE LOW WILL BE NEAR THE FORECAST AREA TONIGHT AND OFF
THE COAST TUESDAY. WINTER-TYPE PRECIPITATION WILL OCCUR ACROSS THE
NORTHERN PORTIONS OF SC BECAUSE OF THE COLDER AIR MASS IN PLACE
AHEAD OF THE SYSTEM. WELL BELOW NORMAL TEMPERATURES EXPECTED
THROUGH THE WEEK UNDER THE INFLUENCE OF AN ARCTIC AIR MASS.
&&
.NEAR TERM /THROUGH TONIGHT/...
BROAD UPPER LEVEL TROUGH IN THE MIDWEST WILL SHIFT EAST WITH
RESULTING FLOW INCREASING FROM THE SOUTHWEST ACROSS THE CAROLINAS.
SURFACE HIGH PRESSURE RIDGING INTO THE AREA BEGINNING TO SHIFT TO
THE NORTHEAST AS LOW PRESSURE TRACKING FROM THE LOWER MISSISSIPPI
VALLEY APPROACHES THE REGION. AIR MASS REMAINS QUITE COLD AND DRY
WITH TEMPERATURES IN THE 30S LATE THIS MORNING AND DEW POINTS IN
THE SINGLE DIGITS IN MOST LOCATIONS. MODELS ARE CONTINUING TO
TREND FURTHER NORTH WITH APPROACHING SURFACE LOW PRESSURE. LATEST
MODELS IN GOOD AGREEMENT WITH SURFACE LOW TRACK ACROSS THE
CSRA/CENTRAL MIDLANDS TONIGHT TO OFF THE NORTH CAROLINA COAST
TUESDAY MORNING. LOW LEVEL WARM ADVECTION/ISENTROPIC LIFT WILL
DEVELOP LATER THIS AFTERNOON ACROSS THE REGION AS THE LOW PRESSURE
AREA APPROACHES. IN-SITU WEDGE LIKELY TO SET UP ACROSS THE
NORTHERN MIDLANDS AND PIEDMONT WITH SHALLOW SURFACE BASED COLD
LAYER. TEMPERATURES WILL STRUGGLE TO RISE THROUGH THE 30S IN THOSE
AREAS. AIR MASS INITIALLY DRY...SO PRECIPITATION MAY BE DELAYED
UNTIL EARLY EVENING. HRRR APPEARS TO BE TRACKING WELL WITH CURRENT
RADAR TRENDS AND IS MUCH FASTER WITH THE PRECIP REACHING THE AREA
THAN THE 12Z NAM. THIS AGREES PRETTY WELL WITH TIMING IN CURRENT
FORECAST SO HAVE NOT MADE ANY ADJUSTMENTS. PRECIPITABLE WATER
INCREASES TO NEAR 1.3 INCHES BY 06Z TUESDAY AND ISENTROPIC LIFT IS
STRONG DURING THIS TIME SO BELIEVE PRECIPITATION MAY BE MODERATE
AT TIMES. MODEL SOUNDINGS INDICATE DEEP WARM NOSE ACROSS THE
REGION TONIGHT AS VERY STRONG LOW LEVEL WARM ADVECTION DEVELOPS.
SOUTHWEST 850MB JETMAX GREATER THAN 60KTS. SHALLOW FREEZING LAYER
LIKELY HOWEVER NORTH OF CAE. LARGE TEMPERATURE GRADIENT EXPECTED
WITH FREEZING TEMPS NORTH OF CAE TONIGHT TO POSSIBLY LOW 50S IN
THE CSRA AS WARM ADVECTION INCREASES AND DEEPENS. TEMPERATURES
EXPECTED TO RISE OVERNIGHT IN THE SOUTHERN AREAS.
WITH DEEP WARM NOSE AND SHALLOW FREEZING LAYER...PRECIPITATION
TYPE MOST LIKELY TO BE FREEZING RAIN IN THE NORTH
MIDLANDS...PIEDMONT AND PEE DEE OVERNIGHT. ICING ESTIMATE UP TO
0.20 INCHES IN THE LANCASTER REGION SEEMS APPROPRIATE GIVEN
EXPECTED QPF. FREEZING RAIN ADVISORY REMAINS IN EFFECT. WINTRY
PRECIPITATION ACROSS THE REST OF THE CWA APPEARS UNLIKELY GIVEN
CURRENT LOW TRACK ACROSS THE SOUTH-CENTRAL MIDLANDS/CSRA.
&&
.SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...
BOTH THE NAM AND GFS SHOW THE CENTER OF THE LOW ALONG THE VA/NC
COAST BY 12Z TUESDAY MORNING WITH MOISTURE DECREASING ACROSS THE
AREA AS THE LOW CONTINUES TO SHIFT FURTHER NORTHEAST THROUGH THE
DAY ON TUESDAY. SHORTWAVE ENERGY ASSOCIATED WITH THE TROUGH WILL
PROMOTE A SLIGHT CHANCE OF LIGHT PRECIP TUESDAY MORNING AS IT
CROSSES THE REGION. MODEL SOUNDINGS SUGGEST MOISTURE BECOMING
QUITE SHALLOW EARLY TUESDAY...KEPT LOW CHANCE POPS AND
PRECIPITATION MAINLY LIQUID RAIN ALTHOUGH LIGHT FREEZING
RAIN/DRIZZLE POSSIBLE IN THE NORTH MIDLANDS THROUGH ABOUT 15Z.
DRYING WILL OCCUR BY TUESDAY AFTERNOON. HIGHS ON TUESDAY ARE
FORECAST NEAR 40 NORTH TO THE LOW 50S SOUTH. DECREASING CLOUDS
TUESDAY NIGHT WILL PROMOTE LOWS IN THE UPPER 20S NORTH TO LOWER
30S SOUTH.
HIGHLY AMPLIFIED UPPER TROUGH OVER THE EASTERN CONUS WEDNESDAY
SUPPORTS BELOW NORMAL TEMPERATURES WITH SOME MID AND HIGH LEVEL
CLOUDS ASSOCIATED WITH SHORT WAVE TROUGHS.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
MODELS ARE IN GOOD AGREEMENT THROUGH FRIDAY NIGHT WITH INCREASING
DIFFERENCES SATURDAY THROUGH MONDAY. HIGHLY AMPLIFIED UPPER LEVEL
PATTERN THROUGH THE LONG TERM WILL KEEP AN UPPER LEVEL RIDGE OVER
THE WEST COAST WITH A TROUGH OVER THE EASTERN US. THIS WILL KEEP
AN ACTIVE PATTERN ACROSS THE FORECAST AREA WITH SYSTEMS EVERY
COUPLE OF DAYS. HIGH PRESSURE ALONG WITH COOLER AND DRIER AIR WILL
BUILD INTO THE REGION WEDNESDAY NIGHT WITH THE UPPER LEVEL TROUGH
AXIS JUST WEST OF THE REGION. THE HIGH WILL BE CENTERED JUST NORTH
OF THE REGION ON THURSDAY THEN EJECT NORTHEASTWARD ON FRIDAY AS
THE NEXT LOW PRESSURE SYSTEM MOVES INTO THE GREAT LAKES REGION
WITH A SECONDARY LOW EXPECTED TO DEVELOP IN CENTRAL TX. MODELS
DIFFER ON THE HANDLING OF THE TX LOW...HOWEVER AGREE ON A FRONTAL
BOUNDARY ACROSS THE FORECAST AREA FOR FRIDAY NIGHT THROUGH MONDAY.
HAVE TRENDED MUCH OF THE LONG TERM TOWARD THE GFS AS RUN TO RUN
CONSISTENCY HAS BEEN BETTER THEN THE ECMWF WHICH HAS MADE
SIGNIFICANT RUN TO RUN CHANGES REGARDING THE TX LOW. TEMPERATURES
THROUGH THE LONG TERM WILL BE SLIGHTLY TO WELL BELOW NORMAL.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
VFR CONDITIONS THROUGH EARLY EVENING THEN MVFR/IFR CONDITIONS FOR
THE REMAINDER OF THE PERIOD.
LOW PRESSURE OVER THE LOWER MISSISSIPPI VALLEY WILL MOVE EAST
ACROSS THE GULF COAST STATES TODAY AND CROSS THE FORECAST AREA
OVERNIGHT. CLOUDS CONTINUE TO THICKEN AND LOWER THIS AFTERNOON AS
MOISTURE INCREASES AHEAD OF THE APPROACHING LOW. GENERALLY EAST
WINDS GRADUALLY SHIFTING SOUTHEAST INTO EARLY EVENING...THEN
TURNING SOUTHERLY AND INCREASING TO AROUND 15-20 MPH WITH SOME
STRONGER GUSTS AS LOW PRESSURE MOVES INTO THE STATE. DRY AIR IN
PLACE WILL HELP TO EVAPORATE PRECIPITATION AS IT MOVES IN LATE
AFTERNOON BUT LIGHT RAIN SHOULD REACH TERMINALS AFTER 22Z-23Z AND
BECOME MORE WIDESPREAD BY 02Z-03Z AT AGS/DNL/CAE/CUB AND 04Z-06Z
AT OGB. CIGS AND VSBYS WILL DROP TO MVFR AT THE ONSET AND THEN
CIGS FALL TO IFR FOR A PERIOD OF TIME AS THE LOW CROSSES THE AREA
AND WINDS SHIFT TO THE WEST AND NORTHWEST AFTER THE LOW PASSES BY.
FREEZING RAIN IS NOT EXPECTED AT THE TERMINALS. CONDITIONS SLOWLY
IMPROVE AFTER 12Z FROM WEST TO EAST BUT CIGS REMAIN RESTRICTED.
EXTENDED AVIATION OUTLOOK...MVFR...POSSIBLE IFR...RESTRICTIONS
COULD LINGER INTO TUESDAY NIGHT. BREEZY CONDITIONS EXPECTED
WEDNESDAY.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...FREEZING RAIN ADVISORY UNTIL 7 AM EST TUESDAY FOR SCZ015-016-
020>022.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
152 PM CST MON FEB 16 2015
.SHORT TERM...
329 AM CST
THROUGH THURSDAY...
TEMPERATURES AND WIND CHILLS WILL BE THE PRIMARY FORECAST
CONCERN...ESPECIALLY BY MID TO LATE WEEK AS A POTENTIALLY RECORD
BREAKING ARCTIC AIR MASS TAKES HOLD OF THE AREA FOR A COUPLE OF DAYS.
TEMPERATURES TODAY SHOULD WARM A FEW DEGREES WARMER THAN THOSE
OBSERVED ON SUNDAY. OVERALL...THIS SHOULD PUT HIGHS IN THE UPPER
TEENS TO THE LOW 20S ACROSS THE REGION. A SIGNIFICANT WINTER
STORM...WHICH IS CURRENTLY IMPACTING AREAS FROM CENTRAL ILLINOIS
SOUTHWARD...WILL CONTINUE TO SPREAD ACCUMULATING SNOW ACROSS THIS
REGION TODAY. FOR NORTHERN ILLINOIS AND NORTHWESTERN INDIANA...ALL
WE SHOULD HAVE TO DEAL WITH IS SOME HIGHER LEVEL CLOUDINESS DURING
THE DAY TODAY.
AS STATED IN THE PREVIOUS DISCUSSION...A SIGNIFICANT PIECE OF THE
POLAR VORTEX WILL BE DISLODGED AND FORCED SOUTHWARD OVER THE GREAT
LAKES REGION BY MID WEEK. THIS SHOULD ALLOW A TRUE ARCTIC AIR MASS
FEATURING -20 TO -24 DEGREE CELSIUS 925 MB TEMPERATURES TO SHIFT OUT
OF THE NORTHWEST TERRITORIES OF CANADA RIGHT ACROSS THE CENTRAL
PORTION OF THE COUNTRY. GUIDANCE CONTINUES IN GOOD AGREEMENT WITH THE
HEAT OF THIS AIR MASS MOVING OVER NORTHERN ILLINOIS/NORTHWESTERN
INDIANA ON THURSDAY. THIS TYPE OF AIR MASS IS CAPABLE OF PRODUCING
HIGH TEMPERATURES IN SINGLE DIGITS ABOVE ZERO AREA-WIDE...AND IF
THIS MATERIALIZES COULD RESULT IN RECORD COLD MAX TEMPERATURES FOR
THE DATE ON THURSDAY. SEE CLIMO SECTION BELOW FOR TEMPERATURE
RECORDS FOR CHICAGO AND ROCKFORD.
UNFORTUNATELY...WITH THESE BITTERLY COLD TEMPERATURES WE HAVE TO
TALK ABOUT WIND CHILLS AGAIN. WITH THE LIKELIHOOD OF A 10 TO 15 KT
SUSTAINED NORTHWESTERLY WIND FOR MUCH OF THE PERIOD INTO
THURSDAY...WIND CHILLS WILL LIKELY REACH ADVISORY LEVEL CRITERIA OF
-20 TO -30...ESPECIALLY WEDNESDAY NIGHT INTO THURSDAY. THIS WOULD BE
THE MOST LIKELY PERIOD OF WIND CHILLS FALLING BELOW -20.
HOWEVER...TUESDAY NIGHT AND THURSDAY NIGHT WILL NOT FAVOR MUCH
BETTER...AND COULD BE CLOSE IN MY NORTHERN AREAS FOR NEEDING A
HEADLINE. EITHER WAY YOU LOOK AT IT...IT WILL BE VERY COLD.
ALTHOUGH NO BIG SNOW EVENTS ARE EXPECTED OVER THE NEXT FEW
DAYS...THERE WILL LIKELY BE PERIODS OF FLURRIES AT TIMES TONIGHT
INTO WEDNESDAY AS SEVERAL MINOR MID LEVEL DISTURBANCES IMPACT THE
AREA. HOWEVER...IT APPEARS THE BEST CHANCE FOR SOME BETTER SNOW
SHOWER ACTIVITY..WITH SOME POSSIBLE MINOR ACCUMULATIONS COULD ENTER
THE PICTURE LATE TUESDAY NIGHT INTO WEDNESDAY MORNING. DURING THIS
PERIOD...A SIGNIFICANT PV ANOMALY IS EXPECTED TO SHIFT ACROSS THE
AREA. FORCED LARGE SCALE ASCENT FROM THIS FEATURE...COMBINED WITH
STEEPENING LOW LEVEL LAPSE RATES WITH ARRIVAL OF THE ARCTIC AIR MASS
COULD RESULT IN A FEW SNOW SQUALLS...POTENTIALLY RESULTING IN SOME
MINOR ACCUMULATING SNOWS OVER THE AREA INTO EARLY WEDNESDAY.
THE DEEP ARCTIC AIR MASS WILL ALSO GET LAKE EFFECT SNOWS GOING AGAIN
LATER TONIGHT THROUGH THURSDAY. HOWEVER...IT CONTINUES TO LOOK AS
THOUGH MUCH OF THE FOCUS FOR THIS ACTIVITY WILL REMAIN LARGELY ALONG
THE EASTERN AND SOUTHERN SHORES OF LAKE MICHIGAN. WE WILL CONTINUE
TO MENTION SOME CHANCES FOR THESE SHOWERS ACROSS MAINLY NORTHEASTERN
PORTER COUNTIES IN INDIANA DURING MUCH OF THIS PERIOD...BUT IT EVEN
APPEARS THAT MUCH OF THE ACCUMULATION POTENTIAL WILL REMAIN TO THE
EAST.
KJB
&&
.LONG TERM...
329 AM CST
THURSDAY NIGHT THROUGH SUNDAY...
IF THERE IS ANY GOOD NEWS WITH THIS COLD AIR OUTBREAK...IT WOULD
BE THAT IT LOOKS TO BE FAIRLY PROGRESSIVE. THEREFORE...WARMER
CONDITIONS SHOULD BEGIN TO SET UP ACROSS THE REGION BY FRIDAY AND
INTO NEXT WEEKEND. HOWEVER...THIS WILL BE NO MEANS BE A WARM
SPELL...TEMPERATURES WILL STILL REMAIN BELOW NORMAL THROUGH...AND
BEYOND THE CURRENT FORECAST PERIOD. SOMETIMES THE MODELS DO TRY TO
ERODE THE COLD AIR TOO FAST...SO IT IS POSSIBLE THAT THE WARM UP
COULD BE SLOWER THAN CURRENTLY FORECAST.
THE OTHER CONCERN DURING THE LATER PORTION OF THE PERIOD WILL BE
THE POTENTIAL FOR A MORE ACTIVE PERIOD OF WEATHER...PARTICULARLY
LATE FRIDAY AND INTO THE WEEKEND. MODEL GUIDANCE CONTINUES TO SHOW
CONSIDERABLE DISAGREEMENT FOLLOWING THE PASSAGE OF THE HEART OF
THE MIDWEEK ARCTIC AIR MASS. THEREFORE CONFIDENCE ON SNOWFALL
POTENTIAL ACROSS THE AREA DURING THIS PERIOD REMAINS LOW.
KJB
&&
.CLIMATE...
WHILE THE COLDEST AIR ALOFT ARRIVES WEDNESDAY...THE COLDEST SURFACE
TEMPERATURES MAY RESULT ON THURSDAY FEBRUARY 19TH...WHICH RIGHT NOW
APPEARS COULD JEOPARDIZE SOME RECORDS...ESPECIALLY THE LOW MAXS.
FEB 19TH
RECORD LOW RECORD LOW MAX
CHICAGO -7 (1936) 9 (1936)
ROCKFORD -16 (1979) 7 (1959)
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* LIGHT AND VARIABLE WINDS THROUGH LATE AFTERNOON...THEN BECOMING
SWLY-WLY OVERNIGHT WITH SPEEDS ARND 5-7KT.
* SWLY WINDS 10-15KT TOMORROW.
* MVFR CIGS LIKELY LATE TONIGHT WITH...SOME FLURRIES OR LIGHT
SNOW SHOWERS POSSIBLE.
KREIN
//DISCUSSION...UPDATED 18Z...
LOW PRESSURE OVER CANADA AND THE LOWER MISSISSIPPI VALLEY COMBINED
WITH HIGH PRESSURE OVER THE ERN GREAT LAKES AND WESTERN PLAINS HAS
SET UP A COL OVER THE REGION...WITH CALM TO LIGHT AND VARIABLE
WINDS. THE ONLY CLOUD COVER OF SIGNIFICANCE THIS AFTERNOON WILL BE
THE NORTHERN EDGE OF JET STREAM CIRRUS...WITH A STRONG UPPER LEVEL
JET OVER THE OHIO VALLEY. A WEAK SFC TROUGH/COLD FRONT DROPPING
SWD OUT OF THE UPPER MISSISSIPPI VALLEY TONIGHT WILL BRING
INCREASING LOW AND MID CLOUD. WITH A VERY DRY AIRMASS IN
PLACE...THE CHANCES FOR PRECIPITATION ACCOMPANYING THE FRONT ARE
LOW...BUT THERE COULD BE ENOUGH FORCING TO GENERATE SOME SCT
FLURRIES OR LIGHT SNOW SHOWERS...WITH MVFR CIGS. HOWEVER...ANY
SNOW THAT DOES DEVELOP SHOULD HAVE LITTLE OR NO ADDITIONAL IMPACT.
FOLLOWING THE FROPA TOMORROW...WINDS WILL SHIFT TO NORTHWESTERLY
AND THE RESULTANT INCREASING COLD ADVECTION THROUGH THE DAY SHOULD
LEAD TO WINDS INCREASING TO 10-15KT WITH OCNL HIGHER GUSTS OF
18-20KT.
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* MEDIUM-HIGH CONFIDENCE IN MVFR CIGS TONIGHT. MEDIUM CONFIDENCE IN
TIMING AND DURATION.
* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...
TUESDAY NIGHT...CHANCE OF SNOW SHOWERS. MVFR CIGS POSSIBLE. WEST-
NORTHWEST WINDS.
WEDNESDAY...CHANCE OF FLURRIES. MVFR CIGS POSSIBLE. BREEZY NORTHWEST
WINDS.
THURSDAY...MAINLY VFR. NORTHWEST WINDS.
FRIDAY...CHANCE OF SNOW ESPECIALLY FRIDAY NIGHT. MVFR/IFR POSSIBLE
LATE. SOUTH WINDS.
SATURDAY...CHANCE OF SNOW ESPECIALLY IN THE MORNING. MVFR
POSSIBLE. SOUTHWEST WINDS BECOMING NORTHWEST.
SUNDAY...MVFR POSSIBLE. NORTH WINDS.
MDB
&&
.MARINE...
220 AM CST
HIGH PRESSURE OVER LAKE HURON AND LAKE ERIE WILL MOVE EASTWARD
TODAY WHILE A COLD FRONT/TROUGH ACROSS THE NORTHERN PLAINS THIS
MORNING TRACKS SOUTHEAST. THE FRONT WILL CROSS LAKE MICHIGAN
TONIGHT SHIFTING SOUTHERLY WINDS TO THE NORTHWEST. A WEAK LOW WILL
THEN DROP ACROSS THE LAKE TUESDAY NIGHT BRINGING A BETTER PUSH OF
COLD AIR WITH A STRONG HIGH BUILDING INTO THE PLAINS BEHIND IT.
NORTHWEST WINDS WILL INTENSIFY WEDNESDAY WITH LOW END GALES STILL
LOOKING LIKE A GOOD POSSIBILITY FOR MOST OF WEDNESDAY AND
WEDNESDAY NIGHT ACROSS CENTRAL AND SOUTHERN PORTIONS OF THE LAKE.
WINDS WILL VERY SLOWLY EASE THURSDAY WITH THE PRESSURE GRADIENT
BEING SLOW TO WEAKEN BETWEEN LOW PRESSURE TO THE EAST AND THE
APPROACHING HIGH FROM THE WEST. THE HIGH SHOULD PUSH OVERHEAD
EARLY FRIDAY BRINGING MUCH LIGHTER WINDS BUT THIS WILL BE SHORT
LIVED AS ANOTHER LOW LOOKS TO AFFECT THE REGION EARLY NEXT
WEEKEND. MODEL GUIDANCE IS AT ODDS NEXT WEEKEND SO DO NOT HAVE
MUCH CONFIDENCE IN ANY DETAILS THIS FAR OUT.
WEB CAMS AND SATELLITE IMAGERY SHOW THE ICE FIELD TO BE PRETTY
EXTENSIVE AROUND THE PERIMETER OF THE LAKE SO HAVE REMOVED WAVES
FROM THE NEARSHORE WATERS.
MDB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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
1148 AM CST Mon Feb 16 2015
.UPDATE...
ISSUED AT 1041 AM CST MON FEB 16 2015
Made a quick update to the forecast to lower PoPs along the
northern edge of the snow area and to drop the Winter Weather
Advisory for Scott, Morgan, Sangamon, and Christian counties.
16z/10am radar mosaic shows light to moderate snow ongoing across
the southern KILX CWA, mainly along/south of a Paris to
Shelbyville line. Still some weak echoes further west just
south of Quincy, so some additional light snow/flurries will
remain possible as far north as Springfield through midday. After
that, the snow area will gradually shift further southeastward and
dissipate as the day progresses. Additional accumulations of
around 1 inch are likely along/south of I-70 through the afternoon
before the snow tapers off to flurries and ends. Elsewhere around
central Illinois, cold and dry conditions will prevail. High temps
will only rise into the lower 20s.
&&
.SHORT TERM...(Today)
ISSUED AT 332 AM CST MON FEB 16 2015
Winter storm continues relatively on track with previous forecast.
Will not make any timing or coverage changes to the Winter Storm
headlines with the morning update. Counties can be cleared from the
headlines early if needed as the snowfall diminishes from NW to SE
this afternoon.
The 5" snowfall report from Edgewood at 150 am in SW Effingham
county lends confidence that the southeast 6 counties in the Winter
Storm Warning will reach into the 6 to 8" range before the end of
this event. Isolated spots may even climb above 8". Radar trends of
the bands of moderate snows are correlating closely to the RAP and
NAM depiction of 700mb Fn frontogenetic convergence. Projecting
forward through the day, our southeast counties will remain under
waves of Fn convergence and steady snows into the afternoon. Along
I-72, snows will be lighter, but the southern portions of the
advisory counties look on track to climb up to 3" before the
snowfall diminishes on the northern periphery. Have continued with
categorical PoPs in the winter storm warning and advisory areas this
morning, with slight chances up to Lincoln to Paris. PoPs were
trended downward each hour this afternoon to correlate with the
eastward translation of mid level forcing and deep moisture.
Additional accumulations today could reach between 2 to 4" in the
Warning counties S of I-70, with 1 to 2 inches for the southern
portions of the advisory counties between I-70 and I-72. Little to
no snowfall is expected north of a line from Rushville to Lincoln to
Champaign.
&&
.LONG TERM...(Tonight through Sunday)
ISSUED AT 332 AM CST MON FEB 16 2015
Have a 20-30% chance of light snow in far southeast IL early this
evening with little additional accumulations then. Best chance of
accumulating snows this evening will be southeast of IL over KY
where as much as 10-16 inches of snow is expected. WNW winds will be
less than 10 mph tonight so limiting the amount of blowing and
drifting snow in southeast IL. Lows tonight of 8-13F with coldest
readings over deeper fresh snow cover in southeast IL. A cold front
to move se across central/se IL Tue morning and generally move
through dry with limited moisture. Have chance of flurries ne
counties overnight into Tue while better chances of light snow
further ne closer to MI/Lake MI. Highs Tue in lower 20s se of IL
river and upper teens nw of the IL river.
00Z forecast models continue to dig a strong upper level trof
southward into the Midwest including IL Tue night and Wed with
another surge of arctic air into the region. Scattered flurries with
mostly cloudy skies to accompany this trof along with bitter cold
temperatures. Lows Tue night around 5F. Highs Wed only in lower
teens eastern/se IL and 5-10F from I-55 west. Brisk nw winds Wed
with gusts 20-30 mph to give wind chills of 10-15 below zero
northern counties. Even colder Wed night with lows in the single
digits below zero and wind chills of 15-25 below zero. Wind chill
advisory may be needed wed night into thu morning even for central
and southeast IL. Strong upper level trof starts to shift east of IL
Thu but still very cold Thu with arctic high pressure moving into MS
river valley. Highs Thu of 8-13F and coldest from I-74 ne.
As high pressure drifts east of IL late this week and upper level
heights and 850 mb temps elevate, temps to moderate to mildest
readings on Sat in low to mid 30s for highs. But still below normal
for late Feb. Continued to stay close to guidance chances of light
snow this weekend starting Friday night. Big differences with
extended models this weekend with ECMWF showing strong low pressure
moving ne into IL Sat night while GFS keeps precipitation south of
central IL this weekend. GEM model through Sat is looking drier like
the GFS model. The Climate Prediction Center (CPC) 8-14 day
temperature outlook for Feb 23-Mar 1 has IL in greater than 70%
chance of below normal temperatures.
&&
.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
ISSUED AT 1148 AM CST MON FEB 16 2015
VFR conditions will prevail at the central Illinois terminals this
afternoon and evening before lower clouds poised well to the
northwest behind an approaching cold front spill into the area
later tonight into Tuesday. Upstream obs show widespread low VFR
ceilings of around 3500ft just ahead of the system across much of
Iowa, with MVFR ceilings behind the boundary across Minnesota into
northern Iowa. Based on satellite timing tools and 12z NAM FROPA,
have introduced MVFR conditions at KPIA by 11z, then further east
to KCMI by 14z. Scattered flurries will occur along/behind the
front within the CAA regime: however, opted to leave mention of
precip out of the forecast. Winds will initially be from the N/NE
at around 5kt this afternoon, but will back to the W/SW ahead of
the system this evening. Once cold front passes, winds will become
northwesterly at around 10kt by late Tuesday morning.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING until 6 PM CST this evening FOR ILZ066>068-
071>073.
WINTER WEATHER ADVISORY until 6 PM CST this evening FOR
ILZ061>063.
&&
$$
UPDATE...Barnes
SHORT TERM...Shimon
LONG TERM...07
AVIATION...Barnes
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1130 AM CST MON FEB 16 2015
.SHORT TERM...
329 AM CST
THROUGH THURSDAY...
TEMPERATURES AND WIND CHILLS WILL BE THE PRIMARY FORECAST
CONCERN...ESPECIALLY BY MID TO LATE WEEK AS A POTENTIALLY RECORD
BREAKING ARCTIC AIR MASS TAKES HOLD OF THE AREA FOR A COUPLE OF DAYS.
TEMPERATURES TODAY SHOULD WARM A FEW DEGREES WARMER THAN THOSE
OBSERVED ON SUNDAY. OVERALL...THIS SHOULD PUT HIGHS IN THE UPPER
TEENS TO THE LOW 20S ACROSS THE REGION. A SIGNIFICANT WINTER
STORM...WHICH IS CURRENTLY IMPACTING AREAS FROM CENTRAL ILLINOIS
SOUTHWARD...WILL CONTINUE TO SPREAD ACCUMULATING SNOW ACROSS THIS
REGION TODAY. FOR NORTHERN ILLINOIS AND NORTHWESTERN INDIANA...ALL
WE SHOULD HAVE TO DEAL WITH IS SOME HIGHER LEVEL CLOUDINESS DURING
THE DAY TODAY.
AS STATED IN THE PREVIOUS DISCUSSION...A SIGNIFICANT PIECE OF THE
POLAR VORTEX WILL BE DISLODGED AND FORCED SOUTHWARD OVER THE GREAT
LAKES REGION BY MID WEEK. THIS SHOULD ALLOW A TRUE ARCTIC AIR MASS
FEATURING -20 TO -24 DEGREE CELSIUS 925 MB TEMPERATURES TO SHIFT OUT
OF THE NORTHWEST TERRITORIES OF CANADA RIGHT ACROSS THE CENTRAL
PORTION OF THE COUNTRY. GUIDANCE CONTINUES IN GOOD AGREEMENT WITH THE
HEAT OF THIS AIR MASS MOVING OVER NORTHERN ILLINOIS/NORTHWESTERN
INDIANA ON THURSDAY. THIS TYPE OF AIR MASS IS CAPABLE OF PRODUCING
HIGH TEMPERATURES IN SINGLE DIGITS ABOVE ZERO AREA-WIDE...AND IF
THIS MATERIALIZES COULD RESULT IN RECORD COLD MAX TEMPERATURES FOR
THE DATE ON THURSDAY. SEE CLIMO SECTION BELOW FOR TEMPERATURE
RECORDS FOR CHICAGO AND ROCKFORD.
UNFORTUNATELY...WITH THESE BITTERLY COLD TEMPERATURES WE HAVE TO
TALK ABOUT WIND CHILLS AGAIN. WITH THE LIKELIHOOD OF A 10 TO 15 KT
SUSTAINED NORTHWESTERLY WIND FOR MUCH OF THE PERIOD INTO
THURSDAY...WIND CHILLS WILL LIKELY REACH ADVISORY LEVEL CRITERIA OF
-20 TO -30...ESPECIALLY WEDNESDAY NIGHT INTO THURSDAY. THIS WOULD BE
THE MOST LIKELY PERIOD OF WIND CHILLS FALLING BELOW -20.
HOWEVER...TUESDAY NIGHT AND THURSDAY NIGHT WILL NOT FAVOR MUCH
BETTER...AND COULD BE CLOSE IN MY NORTHERN AREAS FOR NEEDING A
HEADLINE. EITHER WAY YOU LOOK AT IT...IT WILL BE VERY COLD.
ALTHOUGH NO BIG SNOW EVENTS ARE EXPECTED OVER THE NEXT FEW
DAYS...THERE WILL LIKELY BE PERIODS OF FLURRIES AT TIMES TONIGHT
INTO WEDNESDAY AS SEVERAL MINOR MID LEVEL DISTURBANCES IMPACT THE
AREA. HOWEVER...IT APPEARS THE BEST CHANCE FOR SOME BETTER SNOW
SHOWER ACTIVITY..WITH SOME POSSIBLE MINOR ACCUMULATIONS COULD ENTER
THE PICTURE LATE TUESDAY NIGHT INTO WEDNESDAY MORNING. DURING THIS
PERIOD...A SIGNIFICANT PV ANOMALY IS EXPECTED TO SHIFT ACROSS THE
AREA. FORCED LARGE SCALE ASCENT FROM THIS FEATURE...COMBINED WITH
STEEPENING LOW LEVEL LAPSE RATES WITH ARRIVAL OF THE ARCTIC AIR MASS
COULD RESULT IN A FEW SNOW SQUALLS...POTENTIALLY RESULTING IN SOME
MINOR ACCUMULATING SNOWS OVER THE AREA INTO EARLY WEDNESDAY.
THE DEEP ARCTIC AIR MASS WILL ALSO GET LAKE EFFECT SNOWS GOING AGAIN
LATER TONIGHT THROUGH THURSDAY. HOWEVER...IT CONTINUES TO LOOK AS
THOUGH MUCH OF THE FOCUS FOR THIS ACTIVITY WILL REMAIN LARGELY ALONG
THE EASTERN AND SOUTHERN SHORES OF LAKE MICHIGAN. WE WILL CONTINUE
TO MENTION SOME CHANCES FOR THESE SHOWERS ACROSS MAINLY NORTHEASTERN
PORTER COUNTIES IN INDIANA DURING MUCH OF THIS PERIOD...BUT IT EVEN
APPEARS THAT MUCH OF THE ACCUMULATION POTENTIAL WILL REMAIN TO THE
EAST.
KJB
&&
.LONG TERM...
329 AM CST
THURSDAY NIGHT THROUGH SUNDAY...
IF THERE IS ANY GOOD NEWS WITH THIS COLD AIR OUTBREAK...IT WOULD
BE THAT IT LOOKS TO BE FAIRLY PROGRESSIVE. THEREFORE...WARMER
CONDITIONS SHOULD BEGIN TO SET UP ACROSS THE REGION BY FRIDAY AND
INTO NEXT WEEKEND. HOWEVER...THIS WILL BE NO MEANS BE A WARM
SPELL...TEMPERATURES WILL STILL REMAIN BELOW NORMAL THROUGH...AND
BEYOND THE CURRENT FORECAST PERIOD. SOMETIMES THE MODELS DO TRY TO
ERODE THE COLD AIR TOO FAST...SO IT IS POSSIBLE THAT THE WARM UP
COULD BE SLOWER THAN CURRENTLY FORECAST.
THE OTHER CONCERN DURING THE LATER PORTION OF THE PERIOD WILL BE
THE POTENTIAL FOR A MORE ACTIVE PERIOD OF WEATHER...PARTICULARLY
LATE FRIDAY AND INTO THE WEEKEND. MODEL GUIDANCE CONTINUES TO SHOW
CONSIDERABLE DISAGREEMENT FOLLOWING THE PASSAGE OF THE HEART OF
THE MIDWEEK ARCTIC AIR MASS. THEREFORE CONFIDENCE ON SNOWFALL
POTENTIAL ACROSS THE AREA DURING THIS PERIOD REMAINS LOW.
KJB
&&
.CLIMATE...
WHILE THE COLDEST AIR ALOFT ARRIVES WEDNESDAY...THE COLDEST SURFACE
TEMPERATURES MAY RESULT ON THURSDAY FEBRUARY 19TH...WHICH RIGHT NOW
APPEARS COULD JEOPARDIZE SOME RECORDS...ESPECIALLY THE LOW MAXS.
FEB 19TH
RECORD LOW RECORD LOW MAX
CHICAGO -7 (1936) 9 (1936)
ROCKFORD -16 (1979) 7 (1959)
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* LIGHT AND VARIABLE WINDS THROUGH LATE AFTERNOON...THEN BECOMING
SWLY-WLY OVERNIGHT WITH SPEEDS ARND 5-7KT.
* SWLY WINDS 10-15KT TOMORROW.
* MVFR CIGS LIKELY LATE TONIGHT WITH...SOME FLURRIES OR LIGHT
SNOW SHOWERS POSSIBLE.
KREIN
//DISCUSSION...UPDATED 18Z...
LOW PRESSURE OVER CANADA AND THE LOWER MISSISSIPPI VALLEY COMBINED
WITH HIGH PRESSURE OVER THE ERN GREAT LAKES AND WESTERN PLAINS HAS
SET UP A COL OVER THE REGION...WITH CALM TO LIGHT AND VARIABLE
WINDS. THE ONLY CLOUD COVER OF SIGNIFICANCE THIS AFTERNOON WILL BE
THE NORTHERN EDGE OF JET STREAM CIRRUS...WITH A STRONG UPPER LEVEL
JET OVER THE OHIO VALLEY. A WEAK SFC TROUGH/COLD FRONT DROPPING
SWD OUT OF THE UPPER MISSISSIPPI VALLEY TONIGHT WILL BRING
INCREASING LOW AND MID CLOUD. WITH A VERY DRY AIRMASS IN
PLACE...THE CHANCES FOR PRECIPITATION ACCOMPANYING THE FRONT ARE
LOW...BUT THERE COULD BE ENOUGH FORCING TO GENERATE SOME SCT
FLURRIES OR LIGHT SNOW SHOWERS...WITH MVFR CIGS. HOWEVER...ANY
SNOW THAT DOES DEVELOP SHOULD HAVE LITTLE OR NO ADDITIONAL IMPACT.
FOLLOWING THE FROPA TOMORROW...WINDS WILL SHIFT TO NORTHWESTERLY
AND THE RESULTANT INCREASING COLD ADVECTION THROUGH THE DAY SHOULD
LEAD TO WINDS INCREASING TO 10-15KT WITH OCNL HIGHER GUSTS OF
18-20KT.
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* MEDIUM-HIGH CONFIDENCE IN MVFR CIGS TONIGHT. MEDIUM CONFIDENCE IN
TIMING AND DURATION.
* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...
TUESDAY NIGHT...CHANCE OF SNOW SHOWERS. MVFR CIGS POSSIBLE. WEST-
NORTHWEST WINDS.
WEDNESDAY...CHANCE OF FLURRIES. MVFR CIGS POSSIBLE. BREEZY NORTHWEST
WINDS.
THURSDAY...MAINLY VFR. NORTHWEST WINDS.
FRIDAY...CHANCE OF SNOW ESPECIALLY FRIDAY NIGHT. MVFR/IFR POSSIBLE
LATE. SOUTH WINDS.
SATURDAY...CHANCE OF SNOW ESPECIALLY IN THE MORNING. MVFR
POSSIBLE. SOUTHWEST WINDS BECOMING NORTHWEST.
SUNDAY...MVFR POSSIBLE. NORTH WINDS.
MDB
&&
.MARINE...
220 AM CST
HIGH PRESSURE OVER LAKE HURON AND LAKE ERIE WILL MOVE EASTWARD
TODAY WHILE A COLD FRONT/TROUGH ACROSS THE NORTHERN PLAINS THIS
MORNING TRACKS SOUTHEAST. THE FRONT WILL CROSS LAKE MICHIGAN
TONIGHT SHIFTING SOUTHERLY WINDS TO THE NORTHWEST. A WEAK LOW WILL
THEN DROP ACROSS THE LAKE TUESDAY NIGHT BRINGING A BETTER PUSH OF
COLD AIR WITH A STRONG HIGH BUILDING INTO THE PLAINS BEHIND IT.
NORTHWEST WINDS WILL INTENSIFY WEDNESDAY WITH LOW END GALES STILL
LOOKING LIKE A GOOD POSSIBILITY FOR MOST OF WEDNESDAY AND
WEDNESDAY NIGHT ACROSS CENTRAL AND SOUTHERN PORTIONS OF THE LAKE.
WINDS WILL VERY SLOWLY EASE THURSDAY WITH THE PRESSURE GRADIENT
BEING SLOW TO WEAKEN BETWEEN LOW PRESSURE TO THE EAST AND THE
APPROACHING HIGH FROM THE WEST. THE HIGH SHOULD PUSH OVERHEAD
EARLY FRIDAY BRINGING MUCH LIGHTER WINDS BUT THIS WILL BE SHORT
LIVED AS ANOTHER LOW LOOKS TO AFFECT THE REGION EARLY NEXT
WEEKEND. MODEL GUIDANCE IS AT ODDS NEXT WEEKEND SO DO NOT HAVE
MUCH CONFIDENCE IN ANY DETAILS THIS FAR OUT.
WEB CAMS AND SATELLITE IMAGERY SHOW THE ICE FIELD TO BE PRETTY
EXTENSIVE AROUND THE PERIMETER OF THE LAKE SO HAVE REMOVED WAVES
FROM THE NEARSHORE WATERS.
MDB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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
NATIONAL WEATHER SERVICE LINCOLN IL
1042 AM CST Mon Feb 16 2015
.UPDATE...
ISSUED AT 1041 AM CST MON FEB 16 2015
Made a quick update to the forecast to lower PoPs along the
northern edge of the snow area and to drop the Winter Weather
Advisory for Scott, Morgan, Sangamon, and Christian counties.
16z/10am radar mosaic shows light to moderate snow ongoing across
the southern KILX CWA, mainly along/south of a Paris to
Shelbyville line. Still some weak echoes further west just
south of Quincy, so some additional light snow/flurries will
remain possible as far north as Springfield through midday. After
that, the snow area will gradually shift further southeastward and
dissipate as the day progresses. Additional accumulations of
around 1 inch are likely along/south of I-70 through the afternoon
before the snow tapers off to flurries and ends. Elsewhere around
central Illinois, cold and dry conditions will prevail. High temps
will only rise into the lower 20s.
&&
.SHORT TERM...(Today)
ISSUED AT 332 AM CST MON FEB 16 2015
Winter storm continues relatively on track with previous forecast.
Will not make any timing or coverage changes to the Winter Storm
headlines with the morning update. Counties can be cleared from the
headlines early if needed as the snowfall diminishes from NW to SE
this afternoon.
The 5" snowfall report from Edgewood at 150 am in SW Effingham
county lends confidence that the southeast 6 counties in the Winter
Storm Warning will reach into the 6 to 8" range before the end of
this event. Isolated spots may even climb above 8". Radar trends of
the bands of moderate snows are correlating closely to the RAP and
NAM depiction of 700mb Fn frontogenetic convergence. Projecting
forward through the day, our southeast counties will remain under
waves of Fn convergence and steady snows into the afternoon. Along
I-72, snows will be lighter, but the southern portions of the
advisory counties look on track to climb up to 3" before the
snowfall diminishes on the northern periphery. Have continued with
categorical PoPs in the winter storm warning and advisory areas this
morning, with slight chances up to Lincoln to Paris. PoPs were
trended downward each hour this afternoon to correlate with the
eastward translation of mid level forcing and deep moisture.
Additional accumulations today could reach between 2 to 4" in the
Warning counties S of I-70, with 1 to 2 inches for the southern
portions of the advisory counties between I-70 and I-72. Little to
no snowfall is expected north of a line from Rushville to Lincoln to
Champaign.
&&
.LONG TERM...(Tonight through Sunday)
ISSUED AT 332 AM CST MON FEB 16 2015
Have a 20-30% chance of light snow in far southeast IL early this
evening with little additional accumulations then. Best chance of
accumulating snows this evening will be southeast of IL over KY
where as much as 10-16 inches of snow is expected. WNW winds will be
less than 10 mph tonight so limiting the amount of blowing and
drifting snow in southeast IL. Lows tonight of 8-13F with coldest
readings over deeper fresh snow cover in southeast IL. A cold front
to move se across central/se IL Tue morning and generally move
through dry with limited moisture. Have chance of flurries ne
counties overnight into Tue while better chances of light snow
further ne closer to MI/Lake MI. Highs Tue in lower 20s se of IL
river and upper teens nw of the IL river.
00Z forecast models continue to dig a strong upper level trof
southward into the Midwest including IL Tue night and Wed with
another surge of arctic air into the region. Scattered flurries with
mostly cloudy skies to accompany this trof along with bitter cold
temperatures. Lows Tue night around 5F. Highs Wed only in lower
teens eastern/se IL and 5-10F from I-55 west. Brisk nw winds Wed
with gusts 20-30 mph to give wind chills of 10-15 below zero
northern counties. Even colder Wed night with lows in the single
digits below zero and wind chills of 15-25 below zero. Wind chill
advisory may be needed wed night into thu morning even for central
and southeast IL. Strong upper level trof starts to shift east of IL
Thu but still very cold Thu with arctic high pressure moving into MS
river valley. Highs Thu of 8-13F and coldest from I-74 ne.
As high pressure drifts east of IL late this week and upper level
heights and 850 mb temps elevate, temps to moderate to mildest
readings on Sat in low to mid 30s for highs. But still below normal
for late Feb. Continued to stay close to guidance chances of light
snow this weekend starting Friday night. Big differences with
extended models this weekend with ECMWF showing strong low pressure
moving ne into IL Sat night while GFS keeps precipitation south of
central IL this weekend. GEM model through Sat is looking drier like
the GFS model. The Climate Prediction Center (CPC) 8-14 day
temperature outlook for Feb 23-Mar 1 has IL in greater than 70%
chance of below normal temperatures.
&&
.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
ISSUED AT 600 AM CST MON FEB 16 2015
VFR conditions are expected across the I-74 TAF sites while MVFR
cigs in snow can be expected at times at SPI and DEC this morning.
Cigs could dip down to 2000 feet in some of the steadier snows at SPI,
with periods of 3500 feet where there are breaks in the precip. The
snow should begin to shift southeast of SPI and DEC between 14 and
16z this morning, but MVFR cigs could linger into afternoon. Surface
winds will continue to be relatively light through the period with a
east to northeast wind this morning at 6 to 9 kts. Winds will
back more into a northerly direction this afternoon, then become
SW later tonight ahead of a shortwave. Some MVFR cigs are
projected to affect the I-74 TAF sites after 06z, with a few
flurries possible.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING until 6 PM CST this evening FOR ILZ066>068-
071>073.
WINTER WEATHER ADVISORY until 6 PM CST this evening FOR
ILZ061>063.
&&
$$
UPDATE...Barnes
SHORT TERM...Shimon
LONG TERM...07
AVIATION...Shimon
AREA FORECAST DISCUSSION
NWS GOODLAND KS
208 PM MST MON FEB 16 2015
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 208 PM MST MON FEB 16 2015
LATEST WV IMAGERY AND RAP UPPER LEVEL ANALYSIS SHOWS BROAD TROUGH
ACROSS THE EASTERN US WITH SHORTWAVE ALONG BASE OF TROUGH OVER
COLORADO. AT THE SURFACE LOW PRESSURE REMAINS IN PLACE OVER NORTH
CENTRAL KANSAS...WITH HIGH PRESSURE ACROSS THE NORTHERN ROCKIES
EXTENDING SOUTH TOWARDS NORTHERN COLORADO.
STEEP LOW LEVEL LAPSE RATES AND WEAK INSTABILITY HAVE LED TO
RAIN/SNOW SHOWER DEVELOPMENT THIS AFTERNOON ACROSS THE CWA.
GRAUPEL HAS BEEN OBSERVED WITH SOME OF THIS ACTIVITY. THIS
ACTIVITY WILL MAINLY BE TIED TO DAYTIME HEATING...QUICKLY ENDING
AS LOW LEVELS STABILIZE NEAR SUNSET. THERE WILL BE SOME WEAK
FORCING AROUND THE REGION OVERNIGHT...HOWEVER OTHER THAN MAYBE A
FEW FLURRIES IT DOESNT APPEAR TO BE SUPPORTIVE OF MEASURABLE
PRECIP.
BETTER FORCING IS PROGGED TO MOVE THROUGH THE REGION BY 12Z
TUESDAY AS POSITIVE MID LEVEL VORTICITY ASSOCIATED WITH SHORTWAVE
TROUGH ROTATES INTO THE REGION. THIS WILL RESULT IN SHOWER
REDEVELOPMENT FROM THE NORTH TO THE SOUTH...INCREASING IN COVERAGE
AS LAPSE RATES STEEPEN WITH DAYTIME HEATING. I COULD SEE A
RAIN/SNOW/ICE PELLET MIX AGAIN LIKE TODAY...WITH MINIMAL TO NO
ACCUMULATIONS. UNIDIRECTIONAL GRADIENT AND WINDS ALOFT INCREASE
DURING THE DAY...AND IF WE WERE TO MIX TO 700MB WE COULD SEE
WARNING CRITERIA WINDS MIX TO THE SURFACE. MIXING HEIGHTS APPEAR
TO BE LIMITED DUE TO INCREASING CLOUD COVER...THOUGH THERMAL
PROFILES IN CLEAR SKIES COULD SUPPORT MUCH DEEPER MIXING. FOR NOW
I KEPT GUSTS 45-50MPH. THERE IS A CONCERN THAT SHOWERS COULD HELP
MIX STRONGER WINDS TO THE SURFACE. WINDS COULD ALSO COMBINE WITH
SHOWERS TO REDUCE VISIBILITIES.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 141 PM MST MON FEB 16 2015
WITH THE PASSAGE OF THE SHORTWAVE THRU THE CWA ON TUESDAY...THE TRI
STATE REGION WILL TREND INTO A DRY PERIOD FROM TUESDAY NIGHT RIGHT
INTO 12Z FRIDAY. DURING THIS TIMEFRAME...H5 RIDGE WILL FLATTEN SOME
OVER THE WESTERN PORTION OF THE COUNTRY...ALLOWING FOR WNW FLOW OVER
THE AREA. AT THE SURFACE...HIGH PRESSURE SLIDES SOUTH FROM CANADA
SHIFTING EAST THRU THE WEEK...AND A LEE-SIDE TROUGH SETS UP OVER THE
EASTERN SIDE OF THE ROCKIES. INCREASING WAA WILL RESULT AS SOUTHERLY
FLOW TAPS INTO WARMER AIR. FROM FRIDAY ON THRU NEXT MONDAY...
SHORTWAVE WILL PINWHEEL AROUND BROAD UPPER LOW TO THE EAST...SETTING
UP OVER THE ROCKIES. BLOCKING PATTERN OFF THE WEST COAST...AS WELL
AS OVER THE CENTRAL ATLANTIC OCEAN...KEEPS UPPER TROUGH OVER THE
ROCKIES. THIS SYSTEM WILL BE ABLE TO TAP INTO PACIFIC MOISTURE...
FEEDING IT INTO THE REGION FOR THE PERIOD. AT THE SURFACE HIGH
PRESSURE AGAIN BUILDING DOWN FROM CENTRAL CANADA WILL PROVIDE AN
EASTERLY/UPSLOPE FETCH INTO THE REGION. THE RESULT WILL BE CHANCE
POPS FOR -SW THRU THE ENTIRE FRIDAY THRU MONDAY TIMEFRAME WITH LIGHT
SCATTERED AMOUNTS. A WAA TREND FOR THE FIRST HALF OF THE EXTENDED
WILL GIVE WAY TO BELOW NORMAL NUMBERS WITH THE ARRIVAL OF THE COLD
CANADIAN RIDGE. OVERALL HIGHS WILL RANGE FROM THE 40S WEDNESDAY UP
TO NEAR 60F FOR THURS/FRI...THEN DROP DOWN INTO THE 20S TO L30S FOR
THE WEEKEND INTO NEXT MONDAY. OVERNIGHT LOWS WILL SEE BIG DROP AT
THE END OF THE WEEK WITH CANADIAN RIDGE OVER AREA. LOWS WILL RANGE
FROM THE TEENS AND MID 20S THRU FRIDAY NIGHT...THEN DOWN TO THE
TEENS AND SINGLE NUMBERS OVER THE UPCOMING WEEKEND.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 1058 AM MST MON FEB 16 2015
VFR CONDITIONS SHOULD PREVAIL THROUGH TAF PERIOD. TEMPORARY MVFR
POSSIBLY IFR COULD STILL OCCUR THIS AFTERNOON AND AGAIN TUESDAY AS
SHOW SHOWERS DEVELOP AND MOVE ACROSS THE REGION. LIGHT FOG AND
LOW STRATUS MAY ALSO DEVELOP...HOWEVER GUIDANCE MIGHT BE BIASED
FROM SNOW PACK AND IM NOT PARTICULARLY CONFIDENT IN THIS. I ADDED
MVFR CIG CROUP WAS ADDED AT KMCK AS GUIDANCE IS SHOWING 1500 KFT
AGL CLOUD DECK MOVING OVER THE TERMINAL TUESDAY MORNING. STRONGER
WINDS ARE EXPECTED LATE IN THE TAF PERIOD DEVELOPING FROM THE
WEST TO THE EAST. RESULT WILL BE GUSTS AROUND 35 KT AT KGLD...WITH
HIGHER WINDS OUTSIDE THE TAF PERIOD AT KMCK. AFTERNOON WINDS COULD
BE STRONGER THAT THIS AT BOTH TERMINALS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...JN
AVIATION...DR
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1122 AM CST MON FEB 16 2015
...UPDATE TO AVIATION...
.SYNOPSIS...
ISSUED AT 1027 AM CST MON FEB 16 2015
WV IMAGERY AND 12Z UPPER AIR ANALYSIS INDICATE AN UPPER LEVEL
SHORTWAVE TROUGH DROPPING SOUTHWARD ACROSS THE GREAT BASIN REGION.
MEANWHILE, A WESTERLY FLOW ALOFT PREVAILS ACROSS THE WESTERN HIGH
PLAINS. NEAR THE SURFACE, A BROAD AREA OF ARCTIC HIGH PRESSURE HAS
SETTLED ACROSS THE CENTRAL AND WESTERN HIGH PLAINS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 207 AM CST MON FEB 16 2015
A BAND OF STEADIER SNOWFALL EARLIER THIS MORNING RELATED WELL
WITH A 700MB BAROCLINIC ZONE THAT WAS LOCATED AHEAD OF AN UPPER
LEVEL TROUGH WHICH WAS CROSSING EASTERN COLORADO AS OF 06Z. NAM,
HRRR, AND RAP WERE ALL IN DECENT AGREEMENT WITH THIS BAND OF
STEADIER SNOWFALL CROSSING ALL OF SOUTHWEST AND MOST OF SOUTH
CENTRAL KANSAS BY 12Z MONDAY. SOME LIGHTER SNOWFALL IS STILL
EXPECTED EARLY THIS MORNING SOUTH AND EAST OF A DODGE CITY,
HOWEVER EVEN THIS LIGHT PRECIPITATION IS EXPECTED TO BE ENDING BY
15Z. ADDITIONAL SNOWFALL AMOUNTS EARLY THIS MORNING IN THIS AREA
OF LINGERING SNOWFALL IS EXPECTED TO BE LESS THAN ONE HALF OF AN
INCH. LARGE SCALE SUBSIDENCE IS FORECAST BEHIND THIS UPPER LEVEL
TROUGH AS IT MOVES EAST OF THE AREA EARLY THIS MORNING, HOWEVER
BUFR SOUNDINGS AND EVEN THE HRRR HINT AT SOME LINGERING LOW LEVEL
MOISTURE/STATUS DURING EARLY MORNING HOURS. SOME HIGH LEVEL
MOISTURE/CLOUDS WILL THEN BE POSSIBLE DURING THE AFTERNOON.
CONFIDENCE IS NOT HIGH ON HOW MUCH AFTERNOON CLOUD COVER THERE
WILL BE LATER THIS AFTERNOON, HOWEVER GIVEN THE CURRENT CLOUD
COVER EXPECTED TODAY ALONG WITH THE SNOW THAT FELL DURING THE
OVERNIGHT HOURS WILL UNDERCUT THE COOLER MET GUIDANCE BY SEVERAL
DEGREES. THIS WILL BE CLOSE TO THE PREVIOUS FORECAST FOR HIGHS
TODAY WHICH WILL RANGE FROM THE MID 30S TO NEAR 40.
TONIGHT...CLOUDS WILL BE ON THE INCREASE AS ANOTHER UPPER LEVEL
DISTURBANCE BEGINS TO APPROACH CENTRAL HIGH PLAINS FROM THE
NORTHWEST. A SURFACE BOUNDARY WILL MOVE SOUTH/SOUTHWEST ACROSS
NORTH CENTRAL KANSAS OVERNIGHT WITH SOME INCREASING MOISTURE AND
LIFT DEVELOPING NORTH OF THIS BOUNDARY. THIS MAY GIVE RISE TO A
FEW FLURRIES TOWARDS DAYBREAK. AT THIS TIME GIVEN WHERE THIS
SURFACE BOUNDARY IS EXPECTED TO BE LOCATED TOWARDS 12Z TUESDAY
WILL KEEP A MENTION THE SLIGHT CHANCE FOR LIGHT SNOW GOING ACROSS
MAINLY NORTH CENTRAL KANSAS. WITH THE INCREASING CLOUDS TONIGHT
HAVE DECIDED TO STAY CLOSE TO THE LATEST GUIDANCE WITH
TEMPERATURES FALLING BACK TO AROUND 20 DEGREES.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 333 AM CST MON FEB 16 2015
TUESDAY:
INCREASES POPS NEAR HAYS TUESDAY EVENING AS AN 850-700-HPA WEAK PERTURBATION/BAROCLINIC
ZONE MOVES ACROSS AND COULD PROVIDE THE REGION WITH A SHOWERS/SNOW SHOWERS.
STEEPENING LOW LEVEL LAPSE RATES AND OUTPUT FROM THE ARW CORES AND THE
4 KM NAM GIVE SOME CREDENCE TO THIS. ACTIVITY SHOULD BE FAIRLY LIGHT
IN THE DRY NORTHWESTERLY FLOW ALOFT. TEMPERATURES WILL WARM TO AROUND
40-45F OUTSIDE THIS ACTIVITY ACROSS THE CENTRAL AND SOUTHERN ZONES WITH
COOLER 30S NEAR THE I70 CORRIDOR. OVERNIGHT LOWS WILL BE COLD AND IN
THE UPPER TEENS.
WEDNESDAY:
FAIRLY STRONG NNW FLOW ALOFT WILL CONTINUE ALONG WITH HIGH PRESSURE
ACROSS THE CENTRAL AND NORTHERN PLAINS. THERE WILL BE SOME WEAK LEE
TROUGHING BY WEDNESDAY EVENING AND TEMPERATURES SHOULD MODERATE A FEW
DEGREES - PARTICULARLY ACROSS THE SOUTHWEST ZONES TO MAINLY THE 40S.
NO PRECIPITATION IS EXPECTED.
AND THE REST:
ATTENTION THEN TURNS TO THE WEEKEND. SUPERBLEND STILL HAS CHANCE POPS,
WHICH LOOKS REASONABLE NOW AS THE NEXT WAVE MOVES ACROSS THE CENTRAL
PLAINS. BOTH GFS AND ECMWF SHOW THE CHANCE FOR ACCUMULATING SNOWFALL
WITH THIS NEXT SYSTEM. RIGHT NOW IT IS WAY TOO EARLY TO TELL WHERE AND
HOW MUCH SNOWFALL IS POSSIBLE. ONE THING THAT IS MORE CERTAIN IS MUCH
COOLER TEMPERATURES FOLLOWING A WARM UP. COORDINATED WITH GLD AND TWEAKED
TEMPERATURES SOMEWHAT TO AT LEAST TREND COOLER. TEMPS NOW ARE PROBABLY
WAY TOO WARM AND WILL NEED TO BE ADJUSTED IF THE MODELS CONTINUE AS
ROBUST WITH THIS UPCOMING COLD OUTBREAK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1120 AM CST MON FEB 16 2015
PREDOMINATELY VFR CONDITIONS ARE EXPECTED TO PREVAIL AT
ALL TAF SITES THROUGH EARLY TUESDAY MORNING. LIGHT NORTHWESTERLY
WINDS WILL PERSIST THROUGH THE PERIOD AS A BROAD AREA OF HIGH
PRESSURE MOVES FURTHER EAST ACROSS THE CENTRAL PLAINS.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 40 22 41 19 / 10 10 10 0
GCK 42 20 41 18 / 10 10 10 0
EHA 39 23 42 22 / 10 10 10 0
LBL 40 20 43 20 / 10 10 10 0
HYS 42 22 35 17 / 10 20 20 10
P28 40 23 41 19 / 30 10 20 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...JJOHNSON
SHORT TERM...BURGERT
LONG TERM...SUGDEN
AVIATION...JJOHNSON
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1028 AM CST MON FEB 16 2015
...UPDATE TO SYNOPSIS...
.SYNOPSIS...
ISSUED AT 1027 AM CST MON FEB 16 2015
WV IMAGERY AND 12Z UPPER AIR ANALYSIS INDICATE AN UPPER LEVEL
SHORTWAVE TROUGH DROPPING SOUTHWARD ACROSS THE GREAT BASIN REGION.
MEANWHILE, A WESTERLY FLOW ALOFT PREVAILS ACROSS THE WESTERN HIGH
PLAINS. NEAR THE SURFACE, A BROAD AREA OF ARCTIC HIGH PRESSURE HAS
SETTLED ACROSS THE CENTRAL AND WESTERN HIGH PLAINS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 207 AM CST MON FEB 16 2015
A BAND OF STEADIER SNOWFALL EARLIER THIS MORNING RELATED WELL
WITH A 700MB BAROCLINIC ZONE THAT WAS LOCATED AHEAD OF AN UPPER
LEVEL TROUGH WHICH WAS CROSSING EASTERN COLORADO AS OF 06Z. NAM,
HRRR, AND RAP WERE ALL IN DECENT AGREEMENT WITH THIS BAND OF
STEADIER SNOWFALL CROSSING ALL OF SOUTHWEST AND MOST OF SOUTH
CENTRAL KANSAS BY 12Z MONDAY. SOME LIGHTER SNOWFALL IS STILL
EXPECTED EARLY THIS MORNING SOUTH AND EAST OF A DODGE CITY,
HOWEVER EVEN THIS LIGHT PRECIPITATION IS EXPECTED TO BE ENDING BY
15Z. ADDITIONAL SNOWFALL AMOUNTS EARLY THIS MORNING IN THIS AREA
OF LINGERING SNOWFALL IS EXPECTED TO BE LESS THAN ONE HALF OF AN
INCH. LARGE SCALE SUBSIDENCE IS FORECAST BEHIND THIS UPPER LEVEL
TROUGH AS IT MOVES EAST OF THE AREA EARLY THIS MORNING, HOWEVER
BUFR SOUNDINGS AND EVEN THE HRRR HINT AT SOME LINGERING LOW LEVEL
MOISTURE/STATUS DURING EARLY MORNING HOURS. SOME HIGH LEVEL
MOISTURE/CLOUDS WILL THEN BE POSSIBLE DURING THE AFTERNOON.
CONFIDENCE IS NOT HIGH ON HOW MUCH AFTERNOON CLOUD COVER THERE
WILL BE LATER THIS AFTERNOON, HOWEVER GIVEN THE CURRENT CLOUD
COVER EXPECTED TODAY ALONG WITH THE SNOW THAT FELL DURING THE
OVERNIGHT HOURS WILL UNDERCUT THE COOLER MET GUIDANCE BY SEVERAL
DEGREES. THIS WILL BE CLOSE TO THE PREVIOUS FORECAST FOR HIGHS
TODAY WHICH WILL RANGE FROM THE MID 30S TO NEAR 40.
TONIGHT...CLOUDS WILL BE ON THE INCREASE AS ANOTHER UPPER LEVEL
DISTURBANCE BEGINS TO APPROACH CENTRAL HIGH PLAINS FROM THE
NORTHWEST. A SURFACE BOUNDARY WILL MOVE SOUTH/SOUTHWEST ACROSS
NORTH CENTRAL KANSAS OVERNIGHT WITH SOME INCREASING MOISTURE AND
LIFT DEVELOPING NORTH OF THIS BOUNDARY. THIS MAY GIVE RISE TO A
FEW FLURRIES TOWARDS DAYBREAK. AT THIS TIME GIVEN WHERE THIS
SURFACE BOUNDARY IS EXPECTED TO BE LOCATED TOWARDS 12Z TUESDAY
WILL KEEP A MENTION THE SLIGHT CHANCE FOR LIGHT SNOW GOING ACROSS
MAINLY NORTH CENTRAL KANSAS. WITH THE INCREASING CLOUDS TONIGHT
HAVE DECIDED TO STAY CLOSE TO THE LATEST GUIDANCE WITH
TEMPERATURES FALLING BACK TO AROUND 20 DEGREES.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 333 AM CST MON FEB 16 2015
TUESDAY:
INCREASES POPS NEAR HAYS TUESDAY EVENING AS AN 850-700-HPA WEAK PERTURBATION/BAROCLINIC
ZONE MOVES ACROSS AND COULD PROVIDE THE REGION WITH A SHOWERS/SNOW SHOWERS.
STEEPENING LOW LEVEL LAPSE RATES AND OUTPUT FROM THE ARW CORES AND THE
4 KM NAM GIVE SOME CREDENCE TO THIS. ACTIVITY SHOULD BE FAIRLY LIGHT
IN THE DRY NORTHWESTERLY FLOW ALOFT. TEMPERATURES WILL WARM TO AROUND
40-45F OUTSIDE THIS ACTIVITY ACROSS THE CENTRAL AND SOUTHERN ZONES WITH
COOLER 30S NEAR THE I70 CORRIDOR. OVERNIGHT LOWS WILL BE COLD AND IN
THE UPPER TEENS.
WEDNESDAY:
FAIRLY STRONG NNW FLOW ALOFT WILL CONTINUE ALONG WITH HIGH PRESSURE
ACROSS THE CENTRAL AND NORTHERN PLAINS. THERE WILL BE SOME WEAK LEE
TROUGHING BY WEDNESDAY EVENING AND TEMPERATURES SHOULD MODERATE A FEW
DEGREES - PARTICULARLY ACROSS THE SOUTHWEST ZONES TO MAINLY THE 40S.
NO PRECIPITATION IS EXPECTED.
AND THE REST:
ATTENTION THEN TURNS TO THE WEEKEND. SUPERBLEND STILL HAS CHANCE POPS,
WHICH LOOKS REASONABLE NOW AS THE NEXT WAVE MOVES ACROSS THE CENTRAL
PLAINS. BOTH GFS AND ECMWF SHOW THE CHANCE FOR ACCUMULATING SNOWFALL
WITH THIS NEXT SYSTEM. RIGHT NOW IT IS WAY TOO EARLY TO TELL WHERE AND
HOW MUCH SNOWFALL IS POSSIBLE. ONE THING THAT IS MORE CERTAIN IS MUCH
COOLER TEMPERATURES FOLLOWING A WARM UP. COORDINATED WITH GLD AND TWEAKED
TEMPERATURES SOMEWHAT TO AT LEAST TREND COOLER. TEMPS NOW ARE PROBABLY
WAY TOO WARM AND WILL NEED TO BE ADJUSTED IF THE MODELS CONTINUE AS
ROBUST WITH THIS UPCOMING COLD OUTBREAK.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 500 AM CST MON FEB 16 2015
THE SNOW BAND HAS ALREADY MOVED SOUTHEAST OF THE TERMINALS AND CONDITIONS
ARE VFR NOW. EXPECT VFR TO CONTINUE FOR THE REST OF THE TAF PD. WINDS
WILL BE NORTHWESTERLY TO NORTHERLY AT 5 TO 10 KT.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 40 22 41 19 / 10 10 10 0
GCK 42 21 41 18 / 10 10 10 0
EHA 39 23 42 22 / 10 10 10 0
LBL 40 21 43 20 / 10 10 10 0
HYS 42 22 35 17 / 10 20 20 10
P28 40 23 41 19 / 30 10 20 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...JJOHNSON
SHORT TERM...BURGERT
LONG TERM...SUGDEN
AVIATION...SUGDEN
AREA FORECAST DISCUSSION
NWS CARIBOU ME
1230 PM EST MON FEB 16 2015
.SYNOPSIS...
AN INTENSE AREA OF LOW PRESSURE WILL CONTINUE TO LIFT NORTH OF
MARITIMES THIS AFTERNOON. HIGH PRESSURE ACROSS THE MIDWEST WILL
BUILD TOWARD THE REGION LATER TONIGHT THROUGH TUESDAY. LOW
PRESSURE WILL PASS SOUTH OF THE AREA TUESDAY. ANOTHER LOW WILL
DEVELOP IN THE GULF OF MAINE WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
THE MAIN IMPACTS WILL CONTINUE TO BE WINDS LEADING TO BLOWING AND
DRIFTING SNOW AND THE DANGEROUS WIND CHILLS THRU MID AFTN.
930 AM UPDATE: WE AGAIN XTNDED THE WNTR WX ADV FOR BLOWING AND
DRIFTING SN TIL 21Z. MANY LCTNS WHO RECEIVED SN FROM THE MOST
RECENT PAST SN EVENT ARE STILL CURRENTLY EXPERIENCING NW WIND
GUSTS IN THE 40 TO 45 MPH RANGE...CREATING DANGEROUS WHITEOUTS ON
ROADWAYS WITH OPEN TERRAIN. WE ALSO XTNDED THE WIND CHILL ADV FOR
THE CNTRL HIGHLANDS AND NW TIL 21Z AS WELL...CANCELLING THE WIND
CHILL ADV FOR ZONE 31 WHERE WIND CHILLS HAVE MODERATED WARMER THAN
20 BELOW.
OTHERWISE...FCST AFTN HI TEMPS AND HRLY TEMPS THRU THE REMAINDER
OF THE AFTN WERE MODIFIED BASED ON RECENT SFC OBS...WHICH
INDICATED TEMPS ALREADY NEAR MANY LCTNS...AND EVEN EXCEEDING AT A
FEW LCTNS. FCST HI TEMPS WERE RAISED ABOUT 2 TO 4 DEG F FROM THE
PREV UPDATE TO REFLECT THIS TREND.
ORGNL DISC: 09Z SURFACE ANALYSIS SHOWED 960MB LOW MOVING ACROSS
THE MARITIMES. VERY STRONG GRADIENT IN PLACE ACROSS THE CWA
W/SUSTAINED WINDS 25 TO 35 MPH AND GUSTS AS HIGH AS 45 MPH. SOME
ELEVATED SITES SUCH AS KFVE(FRENCHVILLE) HAD GUSTS TO 50+ MPH
OVERNIGHT. THE STRONG WINDS WILL CONTINUE INTO THE AFTERNOON AND
THEN GRADUALLY LET UP THIS EVENING INTO THE OVERNIGHT HOURS AS THE
GRADIENT LOOSENS. SOUNDING PROFILES SHOWED GUST POTENTIAL TO 50
MPH AGAIN THIS MORNING INTO EARLY AFTERNOON ESPECIALLY ACROSS
NORTHERN AND EASTERN MAINE(WASHINGTON COUNTY). CENTRAL AND
DOWNEAST AREAS WILL SEE GUSTS HIT 40 MPH AT TIMES W/ANOTHER SURGE
AS SHOWN BY THE SOUNDINGS. THIS WILL LEAD TO BLOWING AND DRIFTING
SNOW W/TRAVEL BEING HAZARDOUS AT TIMES. HANCOCK AND WASHINGTON
COUNTIES WILL EXPERIENCE MUCH OF THIS AND SNOW REMOVAL COULD BE
HAMPERED FOR A TIME. RADAR LOOP SHOWED SOME LIGHT SNOW CONTINUING
WHICH WILL ADD TO THE MIX THIS MORNING. THE SNOW IS FORECAST TO
END BY MID MORNING AS FORCING WEAKENS W/THE LOW LIFTING N. THE
NAM12 AND RAP GUIDANCE WERE DOING A FINE JOB W/THIS SETUP.
VERY COLD TEMPERATURES AND THE CONTINUED WINDY CONDITIONS WILL
LEAD TO DANGEROUS WIND CHILLS TODAY AND AGAIN TONIGHT. WE COULD
ACTUALLY BE SEEING WIND CHILL HEADLINES FOR THE ENTIRE REGION BY
TONIGHT INTO TUESDAY MORNING. STAYED PRETTY CLOSE TO THE DAYCREW`S
ASSESSMENT IN THE TEMPERATURES W/SINGLE NUMBERS ALL THE WAY TO
THE COAST. BELOW ZERO TEMPERATURES OVERNIGHT FOR THE ENTIRE CWA
W/THE NORTHERN AREAS POSSIBLY SEEING 15 TO 20 BELOW ESPECIALLY IN
SHELTERED LOCATIONS.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
LOW PRESSURE WILL TRACK NORTHEAST FROM THE MID ATLANTIC REGION
EARLY TUESDAY AND THEN TO THE SOUTH OF NOVA SCOTIA TUESDAY NIGHT.
THIS SYSTEM COULD CLIP DOWN EAST MAINE...MAINLY THE COAST WITH A
LITTLE LIGHT SNOW ON TUESDAY BUT AT THIS TIME LITTLE IF ANY
ACCUMULATION IS EXPECTED. OTHERWISE TUESDAY IS SHAPING UP AS
ANOTHER UNSEASONABLY COLD BUT DRY DAY WITH HIGHS GENERALLY IN THE
TEENS MOST AREAS. EXPECT PARTLY TO MOSTLY CLOUDY SKIES TUESDAY
NIGHT. THE NEXT CHANCE FOR SNOW WILL COME LATER WEDNESDAY AS A
NORLUN TROF TYPE FEATURE DEVELOPS IN THE WAKE OF THE DEPARTING
LOW. AT THIS POINT IT APPEARS THE BEST CHANCE FOR SNOW WILL BE
ACROSS THE SOUTHWEST PORTION OF THE FA THROUGH THE DAY WEDNESDAY.
ANY SNOW ACCUMULATIONS THROUGH THE DAY WEDNESDAY SHOULD BE ON THE
LIGHT SIDE.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
WEDNESDAY NIGHTS AND THURSDAY`S WEATHER WILL BE FOCUSED ON THE
DEVELOPMENT AND PLACEMENT OF A NORLUN TROF TYPE FEATURE AND WEAK
AREA OF LOW PRESSURE THAT IS EXPECTED TO TAKE SHAPE ALONG THE
MAINE MID COAST. MODELS ARE IN VERY GOOD AGREEMENT REGARDING THE
PLACEMENT OF THESE FEATURES FOR WEDNESDAY NIGHT AND THURSDAY.
DECIDED TO RAISE POPS TO CATEGORICAL ACROSS THE ENTIRE AREA
WEDNESDAY NIGHT AND INTO THURSDAY AS JUST ABOUT ALL AREAS SHOULD
SEE SOME SNOW. AT THIS TIME IT LOOKS LIKE GENERALLY LIGHT SNOW
ACCUMULATIONS ARE EXPECTED. THIS SYSTEM WILL MOVE AWAY THURSDAY
NIGHT WITH CONTINUED UNSEASONABLY COLD AND MAINLY DRY CONDITIONS
THURSDAY NIGHT AND FRIDAY WITH NOTHING MORE THAN A FEW SNOW
SHOWERS ACROSS NORTHERN AREAS. LOOKING AHEAD...ANOTHER SYSTEM MAY
MAKE A RUN AT THE AREA LATER SATURDAY INTO SUNDAY WITH A CHANCE
FOR MORE SNOW.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
NEAR TERM: IFR ACROSS THE NORTHERN TERMINALS THROUGH MIDDAY AND
THEN MVFR ESPECIALLY W/VSBYS AND BLOWING SNOW. CONDITIONS LOOK TO
IMPROVE TO VFR THIS EVENING INTO THE OVERNIGHT PERIOD. KBGR AND
KBHB SHOULD SEE VFR RIGHT INTO TONIGHT. TURBULENCE WILL BE A
CONCERN TODAY W/GUSTS HITTING 35-40KT ESPECIALLY THE NORTHERN
TERMINALS.
SHORT TERM: VFR CONDITIONS ARE EXPECTED TUESDAY AND TUESDAY
NIGHT. VFR EXPECTED MOST OF WEDNESDAY. SNOW WILL DEVELOP WEDNESDAY
NIGHT AND CONTINUE INTO THURSDAY WITH IFR CONDITIONS LIKELY.
CONDITIONS WILL IMPROVE TO VFR THURSDAY NIGHT AND FRIDAY.
&&
.MARINE...
NEAR TERM: AFTER COORDINATING W/GYX, DECIDED TO LOWER THE STORM
WARNING TO A GALE WARNING. GUST POTENTIAL OF 40-45 KT EXPECTED
EARLY TODAY. SUSTAINED WINDS OF 30-35 KT INTO EARLY TONIGHT. IT
DOES LOOK AS THOUGH THE CONDITIONS WILL TRANSITION TO SCA AFTER
MIDNIGHT. HEAVY FREEZING SPRAY EXPECTED RIGHT INTO THE AFTERNOON
AND THE WARNING WAS EXTENDED THROUGH 7 PM. CONDITIONS WILL IMPROVE
LATER IN THE EVENING AS THE WINDS DROP OFF. LOOKS LIKE MODERATE
FREEZING SPRAY BY LATE EVENING INTO THE OVERNIGHT HOURS.
SHORT TERM: WIND/SEAS SHOULD REMAIN BELOW SMALL CRAFT ADVISORY
LEVELS TUESDAY THROUGH WEDNESDAY. SCA CONDITIONS ARE THEN POSSIBLE
AGAIN BY THURSDAY. LIGHT FREEZING SPRAY IS EXPECTED TUESDAY
THROUGH WEDNESDAY.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...WINTER WEATHER ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
MEZ002-005-006-011-017-030-032.
WIND CHILL ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR MEZ001-
003-004-010.
MARINE...HEAVY FREEZING SPRAY WARNING UNTIL 7 PM EST THIS EVENING FOR
ANZ050>052.
GALE WARNING UNTIL 1 AM EST TUESDAY FOR ANZ050>052.
&&
$$
NEAR TERM...VJN
SHORT TERM...DUDA
LONG TERM...DUDA
AVIATION...VJN/DUDA
MARINE...VJN/DUDA
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
300 PM CST MON FEB 16 2015
.SHORT TERM...(TONIGHT THROUGH THURSDAY)
ISSUED AT 300 PM CST MON FEB 16 2015
THE PRIMARY FORECAST CONCERN IS POTENTIAL FOR A BAND OF ACCUMULATING
SNOW ACROSS PARTS OF EASTERN NEBRASKA TONIGHT.
UPPER AIR CHARTS FROM 12Z HAD THE FOLLOWING MAIN FEATURES. A STRONG
JETSTREAM WAS NOTED AT 300 MB FROM ALBERTA INTO UTAH...WITH A
COUPLE OF JET SEGMENTS OF OVER 130 KNOTS. A STRONGER JET SEGMENT
OF AROUND 170 KNOTS WAS OVER PENNSYLVANIA. A BROAD AREA OF 12 HOUR
HEIGHT FALLS OF 50 METERS OR MORE AT 500 MB EXTENDED FROM UTAH TO
IOWA AND FROM SOUTH DAKOTA TO TEXAS. A STRONG RIDGE WAS LOCATED
FROM OFF THE CALIFORNIA COAST UP INTO THE YUKON. WINDS WERE
GENERALLY FROM THE NORTHWEST IN THE LOWER AND MIDDLE TROPOSPHERE
FROM OUR AREA NORTHWEST INTO CANADA. PREVIOUSLY MENTIONED 500 MB
RIDGE TO OUR WEST WILL BUILD EAST AND THEN FLATTEN THROUGH
THURSDAY...WHILE A CLOSED LOW FORMS AND DROPS SOUTHEAST ACROSS
ONTARIO AND INTO THE EASTERN GREAT LAKES REGION.
A FAST MOVING SHORTWAVE IN COMBINATION WITH A COMPACT LOW PRESSURE
CENTER SHOULD BRING A BAND OF LIGHT SNOW TO THE REGION TONIGHT.
THE EXACT PLACEMENT OF THIS BAND IS SOMEWHAT UNCERTAIN...BUT THE
LATEST MODEL CONSENSUS (USING A BLEND OF 12Z NAM...18Z NAM...19Z
13 KM RAP ...18Z HRRR AND 15Z SREF MEAN) PLACES THE AXIS FROM
PARTS OF NORTH CENTRAL NEBRASKA INTO NORTHEAST KANSAS. BEST
POTENTIAL IS LIKELY JUST NORTH AND NORTHEAST OF THE TRACK OF THE
SURFACE LOW PRESSURE CENTER. SOUNDINGS...MID LEVEL FRONTOGENESIS
AND IMPRESSIVE 700 MB OMEGA VALUES IN THE DENDRITIC GROWTH ZONE
FROM THE NAM SUGGEST THE ATMOSPHERE MAY PRODUCE SOME AMOUNTS OVER
ONE INCH IN PARTS OF CENTRAL OR SOUTHEAST NEBRASKA DOWN INTO
NORTHEAST KANSAS. BUT WE HAVE MAX AMOUNTS AROUND ONE INCH FOR NOW
AND WILL MENTION THE LOCALIZED POTENTIAL FOR HIGHER AMOUNTS IN THE
HWO. THAT SYSTEM SHOULD PUSH QUICKLY SOUTH OUT OF OUR AREA BY
ABOUT SUNRISE...BUT SOME ISOLATED TO SCATTERED SNOW SHOWERS MAY
OCCUR INTO THE AFTERNOON HOURS. AFTER THAT...SNOW CHANCES SEEM LOW
FROM TUESDAY NIGHT THROUGH WEDNESDAY NIGHT...BUT A SLIGHT CHANCE
OF SNOW WILL RETURN BY THURSDAY.
COLD CANADIAN HIGH PRESSURE WILL BE BUILDING SOUTH FROM ALBERTA
AND SASKATCHEWAN THROUGH WEDNESDAY. WIND CHILLS MAY REACH NEAR
ADVISORY VALUES IN THE NORTH AND NORTHEAST PARTS OF THE FORECAST
AREA LATE TUESDAY NIGHT AND WEDNESDAY MORNING...BUT WILL NOT ISSUE
AN ADVISORY AT THIS POINT. THEN AS THE RIDGE MOVES OFF TO THE
SOUTHEAST AND SOUTHERLY RETURN FLOW DEVELOPS...TEMPERATURES WILL
MODERATE A BIT.
.LONG TERM...(THURSDAY NIGHT THROUGH MONDAY)
ISSUED AT 300 PM CST MON FEB 16 2015
500 MB RIDGE WILL DEVELOP AGAIN FROM THE EASTERN PACIFIC UP INTO
THE YUKON FROM THURSDAY NIGHT INTO SUNDAY. LATEST RUNS OF THE
GFS... ECMWF AND CANADIAN MODELS AGREE ON THE GENERAL LARGE SCALE
FEATURES INTO SUNDAY. DETAILS START TO DIVERGE EARLY NEXT
WEEK...AND CONFIDENCE FALLS TO BELOW NORMAL BY THAT TIME. HAD TO
INCLUDE SOME LOW POPS FOR LIGHT SNOW CHANCES MUCH OF THIS PERIOD.
FRIDAY LOOKS LIKE THE WARMEST DAY...WHEN WE SHOULD SEE HIGHS IN
THE 40S WEST AND 30S EAST. LOWS WILL BE MOSTLY IN THE TEENS...BUT
UPPER TEENS TO MID 20S FOR FRIDAY NIGHT.
&&
.AVIATION...(18Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 1150 AM CST MON FEB 16 2015
AREA WILL REMAIN UNDER THE INFLUENCE OF BROAD NORTHWEST FLOW WITH
TIMING OF SHORT WAVE ENERGY THE MAIN CHALLENGE. WIDESPREAD VFR
CIGS AOB FL050 EXPECTED TO PREVAIL THROUGH THE PERIOD. KLNK COULD
SEE SOME MVFR CIGS AND VSBY AFTER 09Z AS WEAK UPPER WAVE TRIGGERS
SOME LIGHT SNOW POTENTIAL.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
SHORT TERM...MILLER
LONG TERM...MILLER
AVIATION...FOBERT
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
524 PM EST MON FEB 16 2015
.SYNOPSIS...
LOW PRESSURE WILL TRACK SOUTH OF THE REGION TONIGHT AND EARLY
TUESDAY FOLLOWED BY ANOTHER BLAST OF ARCTIC AIR THAT WILL MOVE
INTO THE REGION FOR THE MID TO LATE WEEK PERIOD.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
SFC OBS AND WEB CAMS INDICATE LIGHT SNOW HAS OVERSPREAD PORTIONS
OF SOMERSET...BEDFORD AND FULTON COUNTIES AS OF 22Z. LIGHT SNOW
WILL MARCH NORTHWARD OVERNIGHT...AS SFC WAVE PASSES SOUTH OF PA.
LATEST 4KM NAM AND HRRR SUGGESTS THE SNOW WILL GET TO ARND I-80
BY 03Z...THEN REACH IT/S NORTHERNMOST EXTENT ACROSS THE N MTNS BY
MIDNIGHT.
BEST 850-700MB FRONTOGENETIC FORCING IN MDLS SUGGESTS THE AXIS OF
HEAVIEST SNOW WILL BE SOUTH OF THE PA-MD BORDER...WITH PERHAPS FAR
SRN LANCASTER-YORK COUNTIES PICKING UP SLIGHTLY HIGHER AMOUNTS AS
THE BEST WARM ADVECTION/FRONTOGENESIS MOVES THROUGH OVERNIGHT.
SREF/GEFS SUPPORT CONFINING QPF OF HALF INCH OR MORE SOUTH OF THE
BORDER...LEADING TO A HIGH CONFIDENCE OF A MAINLY LIGHT-MODERATE
SNOWFALL. BLENDED MDL QPF CONTINUES TO INDICATE ONLY ARND 0.20
INCHES ACROSS THE S TIER...WITH ALMOST NOTHING OVR THE N MTNS.
HOWEVER...AN EXAMINATION OF MDL TIME SECTIONS INDICATES NEARLY ALL
LIFT WITHIN THE CLOUD LAYER FALLS WITHIN THE DENDRITIC GROWTH
ZONE...IMPLYING A HIGH SNOW/WATER RATIO OF CLOSE TO 20 TO 1.
THEREFORE...SNOW TOTALS OF NR 4 INCHES STILL SEEM PROBABLE ALONG
THE MD BORDER.
WILL CONTINUE THE WINTER WEATHER ADVISORY WITH NO PLANNED CHANGES
AT THIS POINT IN TIME...FOR THE SOUTHERN 2 LAYERS OF COUNTIES IN
OUR CWA. THE SOUTHERN TIER IS EXPECTED TO SEE BETWEEN 2 AND 4 INCHES
OF SNOW BY THE MORNING COMMUTE TUESDAY...WHILE LESSER AMOUNTS OF
AROUND AN INCH ARE ANTICIPATED ALONG INTERSTATE 80 AND PERHAPS
A DUSTING OVR THE N MTNS.
PRECIP WILL BE TAPERING OFF IN THE HOURS JUST AFTER MIDNIGHT OVER
MY SWRN ZONES WITH MOST OF THE SNOW HAVING ENDED EVEN IN THE EAST
BY AROUND SUNRISE.
OVERNIGHT LOWS WILL AVERAGE IN THE SINGLE DIGITS...TO PERHAPS THE
LOWER TEENS OVER THE SE.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
THE BROAD AREA OF WEAK TO MDT ASCENT ASSOCIATED WITH THE COUPLED
UPPER JET WILL SCOOT QUICKLY EAST OF THE REGION TUESDAY MORNING
FOLLOWED BY WEST-SOUTHWESTERLY FLOW IN THE LOW TO MID
LEVELS...ALLOWING FOR SOME PARTIAL CLEARING IN THE AFTERNOON.
I FOLLOWED MOS POPS MOST CLOSELY LEADING TO A MAINLY DRY DAY FCST
FOR MOST AREAS. THINKING IS THAT ANY LINGERING LIGHT SNOW SHOWERS
WILL BE CONFINED TO WESTERN HIGHER ELEVATIONS.
TEMPS DURING THE DAY TUESDAY WILL WARM BY ANOTHER 10 DEG COMPARED
TO TODAY`S HIGHS. IT`S PRETTY AMAZING THAT EVEN AFTER THE
UPCOMING 2 DAYS OF MODERATING TEMPS...HIGHS TUESDAY WILL STILL BE
15-20 DEG BELOW NORMAL FOR THE DATE.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
VERY COLD AIR WILL CONTINUE TO IMPACT THE REGION THROUGH AT LEAST
THE UPCOMING WORK-WEEK AS A STRONG UPPER LEVEL RIDGE REMAINS OVER
THE WESTERN U.S. AND CONTINUES TO DIRECT POLAR AIR INTO THE
EASTERN U.S. VIA PERSISTENT TROUGH.
SHORT WAVE ENERGY IS FORECAST TO CROSS THE INTO THE PAC LATE IN
THE WEEK AND DIG INTO THE FOUR CORNERS REGION AS THE UPPER RIDGE
REBUILDS NWD INTO WRN CANADA. THIS WILL SHIFT THE UPPER TROF AXIS
NOW COVERING THE EASTERN U.S. - WESTWARD. THIS IN TURN WILL LEAD
TO A FLATTENING OF THE UPPER FLOW OVER THE NORTHEAST NEXT WEEKEND
AND A MODERATION AWAY FROM THE BITTER COLD IN THE CURRENT PATTERN.
PRIOR TO THIS LATE WEEK...LARGE SCALE FLOW MODIFICATION WE`LL HAVE
TO DEAL WITH ONE MORE ARCTIC BLAST...THE LEADING EDGE OF WHICH
WILL PUSH ACROSS THE STATE DURING THE DAY WEDNESDAY. SOMEWHAT
SIMILAR TO SATURDAY...WE SEE A WELL-DEFINED AREA OF STEEP 850-500
MB LAPSE RATES AROUND...OR IN EXCESS OF 7C/KM THAT WILL MOVE
ACROSS THE WESTERN MTNS DURING THE EARLY TO MID AFTERNOON...AND
THROUGH THE SUSQ VALLEY EARLY WED EVENING. ALTHOUGH LIKELY NOT AS
EXTENSIVE AND CONSISTENTLY INTENSE OF A LINE THAT WE SAW SATURDAY
/COMPLETE WITH FEW FLASHES OF LIGHTNING IN SOME LOCATIONS/...THE
SQUALLS ASSOCIATED WITH THIS RIBBON OF INSTABILITY WED WILL LIKELY
COME IN THE FORM ONE OR TWO LINES...AND DUMP A QUICK .5 TO 1.5
INCHES OF SNOW - GREATLY IMPACTING TRAVEL FOR A SHORT PERIOD.
BEHIND THIS SYSTEM YET ANOTHER SURGE OF EXTREMELY COLD AIR WILL
SURGE ACROSS THE STATE FOR THE SECOND HALF OF THE WEEK.
SIMILAR...EXTREMELY COLD TEMPS AT 850 MB ARE FORECAST TO MOVE OVER
THE STATE THURSDAY AND FRIDAY /AND COULD BE EVEN A FEW DEG C LOWER
THAN THOSE ASSOCIATED WITH THIS PAST SUNDAY-MONDAY ARCTIC
AIRMASS/. 03Z SREF SHOWS MEAN 850 TEMPS OF -25 TO -28C COVERING
ALL OF CENTRAL PENN WHICH IS ABOUT -3 SIGMA. HIGH TEMPS THURSDAY
MAY STAY A FEW-SVRL DEG F BELOW ZERO AGAIN ACROSS THE NRN
MTNS...AND HOLD IN THE SINGLE DIGITS TO LOWER TEENS ACROSS THE
REST OF CENTRAL AND SRN PENN...BEFORE MODERATING BY 5-7 DEG
FRIDAY. MORNING LOWS THURSDAY AND FRIDAY COULD RIVAL THOSE OF
SUNDAY AND MONDAY MORNING.
THE CENTER OF THIS NEXT ARCTIC HIGH MAY SLIDE JUST SOUTH OF THE
REGION THEN OFF THE MID ATLANTIC COAST - PER THE 00Z EC...WHILE
THE GEFS WOULD SUGGEST A LITTLE MORE IN THE WAY OF LLVL COLD AIR
DAMMING OVER THE CWA...PRECEDING INCREASING MOISTURE AND A WINTRY
MIX OR SNOW SPREADING IN FROM THE SW...THEN ANOTHER PUSH OF
ARCTIC AIR FOR LATE SUNDAY AND MONDAY.
TEMPERATURES NEXT SUNDAY...HOWEVER...HOLD THE POTENTIAL TO RISE
ABOVE THE FREEZING MARK OVER A GOOD PART OF CENTRAL PA AS THE
EARLIER MENTIONED MODERATION IN THE UPPER FLOW IS FORECAST TO
ARRIVE. THE NEXT SHORTWAVE TROF IS ALSO CURRENTLY TIMED FOR NEXT
WEEKEND...LEADING TO THE POSSIBILITY OF SNOW OR RAIN FOR A CHANGE
OVER SRN PA AND SNOW OVER THEN NORTH.
&&
.AVIATION /22Z MONDAY THROUGH SATURDAY/...
STILL VFR...BUT EXPECT CONDITIONS TO DO DOWN FAST ONCE SNOW
STARTS...GIVEN THE DRY AIRMASS.
MINOR ADJUSTMENTS MADE TO 21Z TAFS.
EARLIER DISCUSSION BELOW.
VFR WITH NO SIG WX CONDITIONS THROUGH LATE AFTERNOON.
LOW PRESSURE MOVING NEWD FROM AL OFF THE MID ATLC COAST OVERNIGHT
WILL SPREAD SNOW AND IFR CONDS ACROSS THE SRN 1/2 OF THE
AIRSPACE LATER THIS AFTERNOON AND OVERNIGHT. SNOW WILL BE QUICK-
HITTING AND END BY 12-15Z TUESDAY FROM WEST TO EAST. HIGHEST
CONFIDENCE IN IFR IS OVER THE SRN AIRFIELDS. USED A BLEND OF HIGH
RES MDLS FOR TIMING WITH SNOW ONSET 21-00Z SPREADING FROM SW TO
NE.
OUTLOOK...
WED-THU...MVFR/IFR -SHSN WRN 1/3. VFR/MVFR -SHSN CENTRAL/ERN 2/3
FRI...BCMG VFR. NO SIG WX.
SAT...MVFR WITH SNOW SHOWERS ASSOC WITH AN APPROACHING COLD FRONT.
&&
.CLIMATE...
MOST OF THE FORECAST AREA WAS ZERO OR COLDER LAST NIGHT WITH
CHANDLER`S VALLEY BEING THE COLDEST COMING IN AT -32.
HARRISBURG AND WILLIAMSPORT BOTH TIED THEIR RECORD LOWS FOR THE
DATE. HARRISBURG WAS 0 AND WILLIAMSPORT WAS -5.
RECORD LOWS/YEAR
HARRISBURG.............0/1905
WILLIAMSPORT..........-5/1905
STATE COLLEGE.........-8/1904
YORK..................-7/1963
ALTOONA...............-2/2004
BRADFORD..............-23/1943
CLEARFIELD............-6/1930
JOHNSTOWN.............-10/1943
LANCASTER.............+2/1987
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 7 AM EST TUESDAY FOR PAZ024>028-
033>036-056-057-059-063>066.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...FITZGERALD/LA CORTE
SHORT TERM...LA CORTE
LONG TERM...GARTNER
AVIATION...LA CORTE/MARTIN
CLIMATE...
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
433 PM EST MON FEB 16 2015
.SYNOPSIS...
LOW PRESSURE WILL TRACK SOUTH OF THE REGION TONIGHT AND EARLY
TUESDAY FOLLOWED BY ANOTHER BLAST OF ARCTIC AIR THAT WILL MOVE
INTO THE REGION FOR THE MID TO LATE WEEK PERIOD.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
SATELLITE LOOP SHOWS CLOUDS CONTINUING TO INCREASE OVER THE REGION
WITH SURFACE OBS SHOWING THE NEAREST SNOW HITTING THE GROUND
MOVING INTO NORTHERN WV-WESTERN VA.
LATEST HRRR HAS LIGHT SNOW OVERSPREADING SWRN AREAS BETWEEN ABOUT
20-23Z POTENTIALLY IMPACTING THE EVENING COMMUTE.
LOOKING AT THE BEST LAYER FRONTOGENETIC FORCING FROM THE NEW NAM
SUGGESTS THE AXIS OF HEAVIEST SNOW WILL BE SOUTH OF THE PA-MD
BORDER...WITH PERHAPS FAR SRN LANCASTER-YORK COUNTIES PICKING UP
SLIGHTLY HIGHER AMOUNTS AS THE BEST WARM ADVECTION/FRONTOGENESIS
MOVES THROUGH OVERNIGHT.
SREF/GEFS SUPPORT CONFINING QPF OF HALF INCH OR MORE SOUTH OF THE
BORDER LEADING TO A HIGH CONFIDENCE OF A MAINLY LIGHT-MODERATE
SNOWFALL.
WILL CONTINUE THE WINTER WEATHER ADVISORY WITH NO PLANNED CHANGES
AT THIS POINT IN TIME...FOR THE SOUTHERN 2 LAYERS OF COUNTIES IN
OUR CWA. THE SOUTHERN TIER IS EXPECTED TO SEE BETWEEN 2 AND 5
INCHES OF SNOW BY THE MORNING COMMUTE TUESDAY...WHILE COUNTY-
LAYER WITHIN THE RT 22/322 CORRIDOR SHOULD SEE MORE ALONG THE
LINES OF 1-4 INCHES. LESSER AMOUNTS OF AROUND 1-2 INCHES ARE
ANTICIPATED TO FALL RIGHT ALONG INTERSTATE 80...WITH AN INCH OR
LESS ACROSS THE MTNS OF NRN PENN.
PRECIP WILL BE TAPERING OFF IN THE HOURS JUST AFTER MIDNIGHT OVER
MY SWRN ZONES WITH MOST OF THE SNOW HAVING ENDED EVEN IN THE EAST
BY AROUND SUNRISE.
OVERNIGHT LOWS WILL AVERAGE IN THE SINGLE DIGITS...TO PERHAPS THE
LOWER TEENS OVER THE SE.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
THE BROAD AREA OF WEAK TO MDT ASCENT ASSOCIATED WITH THE COUPLED
UPPER JET WILL SCOOT QUICKLY EAST OF THE REGION TUESDAY MORNING
FOLLOWED BY WEST-SOUTHWESTERLY FLOW IN THE LOW TO MID
LEVELS...ALLOWING FOR SOME PARTIAL CLEARING IN THE AFTERNOON.
I FOLLOWED MOS POPS MOST CLOSELY LEADING TO A MAINLY DRY DAY FCST
FOR MOST AREAS. THINKING IS THAT ANY LINGERING LIGHT SNOW SHOWERS
WILL BE CONFINED TO WESTERN HIGHER ELEVATIONS.
TEMPS DURING THE DAY TUESDAY WILL WARM BY ANOTHER 10 DEG COMPARED
TO TODAY`S HIGHS. IT`S PRETTY AMAZING THAT EVEN AFTER THE
UPCOMING 2 DAYS OF MODERATING TEMPS...HIGHS TUESDAY WILL STILL BE
15-20 DEG BELOW NORMAL FOR THE DATE.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
VERY COLD AIR WILL CONTINUE TO IMPACT THE REGION THROUGH AT LEAST
THE UPCOMING WORK-WEEK AS A STRONG UPPER LEVEL RIDGE REMAINS OVER
THE WESTERN U.S. AND CONTINUES TO DIRECT POLAR AIR INTO THE
EASTERN U.S. VIA PERSISTENT TROUGH.
SHORT WAVE ENERGY IS FORECAST TO CROSS THE INTO THE PAC LATE IN
THE WEEK AND DIG INTO THE FOUR CORNERS REGION AS THE UPPER RIDGE
REBUILDS NWD INTO WRN CANADA. THIS WILL SHIFT THE UPPER TROF AXIS
NOW COVERING THE EASTERN U.S. - WESTWARD. THIS IN TURN WILL LEAD
TO A FLATTENING OF THE UPPER FLOW OVER THE NORTHEAST NEXT WEEKEND
AND A MODERATION AWAY FROM THE BITTER COLD IN THE CURRENT PATTERN.
PRIOR TO THIS LATE WEEK...LARGE SCALE FLOW MODIFICATION WE`LL HAVE
TO DEAL WITH ONE MORE ARCTIC BLAST...THE LEADING EDGE OF WHICH
WILL PUSH ACROSS THE STATE DURING THE DAY WEDNESDAY. SOMEWHAT
SIMILAR TO SATURDAY...WE SEE A WELL-DEFINED AREA OF STEEP 850-500
MB LAPSE RATES AROUND...OR IN EXCESS OF 7C/KM THAT WILL MOVE
ACROSS THE WESTERN MTNS DURING THE EARLY TO MID AFTERNOON...AND
THROUGH THE SUSQ VALLEY EARLY WED EVENING. ALTHOUGH LIKELY NOT AS
EXTENSIVE AND CONSISTENTLY INTENSE OF A LINE THAT WE SAW SATURDAY
/COMPLETE WITH FEW FLASHES OF LIGHTNING IN SOME LOCATIONS/...THE
SQUALLS ASSOCIATED WITH THIS RIBBON OF INSTABILITY WED WILL LIKELY
COME IN THE FORM ONE OR TWO LINES...AND DUMP A QUICK .5 TO 1.5
INCHES OF SNOW - GREATLY IMPACTING TRAVEL FOR A SHORT PERIOD.
BEHIND THIS SYSTEM YET ANOTHER SURGE OF EXTREMELY COLD AIR WILL
SURGE ACROSS THE STATE FOR THE SECOND HALF OF THE WEEK.
SIMILAR...EXTREMELY COLD TEMPS AT 850 MB ARE FORECAST TO MOVE OVER
THE STATE THURSDAY AND FRIDAY /AND COULD BE EVEN A FEW DEG C LOWER
THAN THOSE ASSOCIATED WITH THIS PAST SUNDAY-MONDAY ARCTIC
AIRMASS/. 03Z SREF SHOWS MEAN 850 TEMPS OF -25 TO -28C COVERING
ALL OF CENTRAL PENN WHICH IS ABOUT -3 SIGMA. HIGH TEMPS THURSDAY
MAY STAY A FEW-SVRL DEG F BELOW ZERO AGAIN ACROSS THE NRN
MTNS...AND HOLD IN THE SINGLE DIGITS TO LOWER TEENS ACROSS THE
REST OF CENTRAL AND SRN PENN...BEFORE MODERATING BY 5-7 DEG
FRIDAY. MORNING LOWS THURSDAY AND FRIDAY COULD RIVAL THOSE OF
SUNDAY AND MONDAY MORNING.
THE CENTER OF THIS NEXT ARCTIC HIGH MAY SLIDE JUST SOUTH OF THE
REGION THEN OFF THE MID ATLANTIC COAST - PER THE 00Z EC...WHILE
THE GEFS WOULD SUGGEST A LITTLE MORE IN THE WAY OF LLVL COLD AIR
DAMMING OVER THE CWA...PRECEDING INCREASING MOISTURE AND A WINTRY
MIX OR SNOW SPREADING IN FROM THE SW...THEN ANOTHER PUSH OF
ARCTIC AIR FOR LATE SUNDAY AND MONDAY.
TEMPERATURES NEXT SUNDAY...HOWEVER...HOLD THE POTENTIAL TO RISE
ABOVE THE FREEZING MARK OVER A GOOD PART OF CENTRAL PA AS THE
EARLIER MENTIONED MODERATION IN THE UPPER FLOW IS FORECAST TO
ARRIVE. THE NEXT SHORTWAVE TROF IS ALSO CURRENTLY TIMED FOR NEXT
WEEKEND...LEADING TO THE POSSIBILITY OF SNOW OR RAIN FOR A CHANGE
OVER SRN PA AND SNOW OVER THEN NORTH.
&&
.AVIATION /22Z MONDAY THROUGH SATURDAY/...
STILL VFR...BUT EXPECT CONDITIONS TO DO DOWN FAST ONCE SNOW
STARTS...GIVEN THE DRY AIRMASS.
MINOR ADJUSTMENTS MADE TO 21Z TAFS.
EARLIER DISCUSSION BELOW.
VFR WITH NO SIG WX CONDITIONS THROUGH LATE AFTERNOON.
LOW PRESSURE MOVING NEWD FROM AL OFF THE MID ATLC COAST OVERNIGHT
WILL SPREAD SNOW AND IFR CONDS ACROSS THE SRN 1/2 OF THE
AIRSPACE LATER THIS AFTERNOON AND OVERNIGHT. SNOW WILL BE QUICK-
HITTING AND END BY 12-15Z TUESDAY FROM WEST TO EAST. HIGHEST
CONFIDENCE IN IFR IS OVER THE SRN AIRFIELDS. USED A BLEND OF HIGH
RES MDLS FOR TIMING WITH SNOW ONSET 21-00Z SPREADING FROM SW TO
NE.
OUTLOOK...
WED-THU...MVFR/IFR -SHSN WRN 1/3. VFR/MVFR -SHSN CENTRAL/ERN 2/3
FRI...BCMG VFR. NO SIG WX.
SAT...MVFR WITH SNOW SHOWERS ASSOC WITH AN APPROACHING COLD FRONT.
&&
.CLIMATE...
MOST OF THE FORECAST AREA WAS ZERO OR COLDER LAST NIGHT WITH
CHANDLER`S VALLEY BEING THE COLDEST COMING IN AT -32.
HARRISBURG AND WILLIAMSPORT BOTH TIED THEIR RECORD LOWS FOR THE
DATE. HARRISBURG WAS 0 AND WILLIAMSPORT WAS -5.
RECORD LOWS/YEAR
HARRISBURG.............0/1905
WILLIAMSPORT..........-5/1905
STATE COLLEGE.........-8/1904
YORK..................-7/1963
ALTOONA...............-2/2004
BRADFORD..............-23/1943
CLEARFIELD............-6/1930
JOHNSTOWN.............-10/1943
LANCASTER.............+2/1987
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 7 AM EST TUESDAY FOR PAZ024>028-
033>036-056-057-059-063>066.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...LA CORTE
SHORT TERM...LA CORTE
LONG TERM...GARTNER
AVIATION...LA CORTE/MARTIN
CLIMATE...LA CORTE
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
352 PM EST MON FEB 16 2015
.SYNOPSIS...
LOW PRESSURE WILL TRACK SOUTH OF THE REGION TONIGHT AND EARLY
TUESDAY FOLLOWED BY ANOTHER BLAST OF ARCTIC AIR THAT WILL MOVE
INTO THE REGION FOR THE MID TO LATE WEEK PERIOD.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
SATELLITE LOOP SHOWS CLOUDS CONTINUING TO INCREASE OVER THE REGION
WITH SURFACE OBS SHOWING THE NEAREST SNOW HITTING THE GROUND
MOVING INTO NORTHERN WV-WESTERN VA.
LATEST HRRR HAS LIGHT SNOW OVERSPREADING SWRN AREAS BETWEEN ABOUT
20-23Z POTENTIALLY IMPACTING THE EVENING COMMUTE.
LOOKING AT THE BEST LAYER FRONTOGENETIC FORCING FROM THE NEW NAM
SUGGESTS THE AXIS OF HEAVIEST SNOW WILL BE SOUTH OF THE PA-MD
BORDER...WITH PERHAPS FAR SRN LANCASTER-YORK COUNTIES PICKING UP
SLIGHTLY HIGHER AMOUNTS AS THE BEST WARM ADVECTION/FRONTOGENESIS
MOVES THROUGH OVERNIGHT.
SREF/GEFS SUPPORT CONFINING QPF OF HALF INCH OR MORE SOUTH OF THE
BORDER LEADING TO A HIGH CONFIDENCE OF A MAINLY LIGHT-MODERATE
SNOWFALL.
WILL CONTINUE THE WINTER WEATHER ADVISORY WITH NO PLANNED CHANGES
AT THIS POINT IN TIME...FOR THE SOUTHERN 2 LAYERS OF COUNTIES IN
OUR CWA. THE SOUTHERN TIER IS EXPECTED TO SEE BETWEEN 2 AND 5
INCHES OF SNOW BY THE MORNING COMMUTE TUESDAY...WHILE COUNTY-
LAYER WITHIN THE RT 22/322 CORRIDOR SHOULD SEE MORE ALONG THE
LINES OF 1-4 INCHES. LESSER AMOUNTS OF AROUND 1-2 INCHES ARE
ANTICIPATED TO FALL RIGHT ALONG INTERSTATE 80...WITH AN INCH OR
LESS ACROSS THE MTNS OF NRN PENN.
PRECIP WILL BE TAPERING OFF IN THE HOURS JUST AFTER MIDNIGHT OVER
MY SWRN ZONES WITH MOST OF THE SNOW HAVING ENDED EVEN IN THE EAST
BY AROUND SUNRISE.
OVERNIGHT LOWS WILL AVERAGE IN THE SINGLE DIGITS...TO PERHAPS THE
LOWER TEENS OVER THE SE.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
THE BROAD AREA OF WEAK TO MDT ASCENT ASSOCIATED WITH THE COUPLED
UPPER JET WILL SCOOT QUICKLY EAST OF THE REGION TUESDAY MORNING
FOLLOWED BY WEST-SOUTHWESTERLY FLOW IN THE LOW TO MID
LEVELS...ALLOWING FOR SOME PARTIAL CLEARING IN THE AFTERNOON.
I FOLLOWED MOS POPS MOST CLOSELY LEADING TO A MAINLY DRY DAY FCST
FOR MOST AREAS. THINKING IS THAT ANY LINGERING LIGHT SNOW SHOWERS
WILL BE CONFINED TO WESTERN HIGHER ELEVATIONS.
TEMPS DURING THE DAY TUESDAY WILL WARM BY ANOTHER 10 DEG COMPARED
TO TODAY`S HIGHS. IT`S PRETTY AMAZING THAT EVEN AFTER THE
UPCOMING 2 DAYS OF MODERATING TEMPS...HIGHS TUESDAY WILL STILL BE
15-20 DEG BELOW NORMAL FOR THE DATE.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
VERY COLD AIR WILL CONTINUE TO IMPACT THE REGION THROUGH AT LEAST
THE UPCOMING WORK-WEEK AS A STRONG UPPER LEVEL RIDGE REMAINS OVER
THE WESTERN U.S. AND CONTINUES TO DIRECT POLAR AIR INTO THE
EASTERN U.S. VIA PERSISTENT TROUGH.
SHORT WAVE ENERGY IS FORECAST TO CROSS THE INTO THE PAC LATE IN
THE WEEK AND DIG INTO THE FOUR CORNERS REGION AS THE UPPER RIDGE
REBUILDS NWD INTO WRN CANADA. THIS WILL SHIFT THE UPPER TROF AXIS
NOW COVERING THE EASTERN U.S. - WESTWARD. THIS IN TURN WILL LEAD
TO A FLATTENING OF THE UPPER FLOW OVER THE NORTHEAST NEXT WEEKEND
AND A MODERATION AWAY FROM THE BITTER COLD IN THE CURRENT PATTERN.
PRIOR TO THIS LATE WEEK...LARGE SCALE FLOW MODIFICATION WE`LL HAVE
TO DEAL WITH ONE MORE ARCTIC BLAST...THE LEADING EDGE OF WHICH
WILL PUSH ACROSS THE STATE DURING THE DAY WEDNESDAY. SOMEWHAT
SIMILAR TO SATURDAY...WE SEE A WELL-DEFINED AREA OF STEEP 850-500
MB LAPSE RATES AROUND...OR IN EXCESS OF 7C/KM THAT WILL MOVE
ACROSS THE WESTERN MTNS DURING THE EARLY TO MID AFTERNOON...AND
THROUGH THE SUSQ VALLEY EARLY WED EVENING. ALTHOUGH LIKELY NOT AS
EXTENSIVE AND CONSISTENTLY INTENSE OF A LINE THAT WE SAW SATURDAY
/COMPLETE WITH FEW FLASHES OF LIGHTNING IN SOME LOCATIONS/...THE
SQUALLS ASSOCIATED WITH THIS RIBBON OF INSTABILITY WED WILL LIKELY
COME IN THE FORM ONE OR TWO LINES...AND DUMP A QUICK .5 TO 1.5
INCHES OF SNOW - GREATLY IMPACTING TRAVEL FOR A SHORT PERIOD.
BEHIND THIS SYSTEM YET ANOTHER SURGE OF EXTREMELY COLD AIR WILL
SURGE ACROSS THE STATE FOR THE SECOND HALF OF THE WEEK.
SIMILAR...EXTREMELY COLD TEMPS AT 850 MB ARE FORECAST TO MOVE OVER
THE STATE THURSDAY AND FRIDAY /AND COULD BE EVEN A FEW DEG C LOWER
THAN THOSE ASSOCIATED WITH THIS PAST SUNDAY-MONDAY ARCTIC
AIRMASS/. 03Z SREF SHOWS MEAN 850 TEMPS OF -25 TO -28C COVERING
ALL OF CENTRAL PENN WHICH IS ABOUT -3 SIGMA. HIGH TEMPS THURSDAY
MAY STAY A FEW-SVRL DEG F BELOW ZERO AGAIN ACROSS THE NRN
MTNS...AND HOLD IN THE SINGLE DIGITS TO LOWER TEENS ACROSS THE
REST OF CENTRAL AND SRN PENN...BEFORE MODERATING BY 5-7 DEG
FRIDAY. MORNING LOWS THURSDAY AND FRIDAY COULD RIVAL THOSE OF
SUNDAY AND MONDAY MORNING.
THE CENTER OF THIS NEXT ARCTIC HIGH MAY SLIDE JUST SOUTH OF THE
REGION THEN OFF THE MID ATLANTIC COAST - PER THE 00Z EC...WHILE
THE GEFS WOULD SUGGEST A LITTLE MORE IN THE WAY OF LLVL COLD AIR
DAMMING OVER THE CWA...PRECEDING INCREASING MOISTURE AND A WINTRY
MIX OR SNOW SPREADING IN FROM THE SW...THEN ANOTHER PUSH OF
ARCTIC AIR FOR LATE SUNDAY AND MONDAY.
TEMPERATURES NEXT SUNDAY...HOWEVER...HOLD THE POTENTIAL TO RISE
ABOVE THE FREEZING MARK OVER A GOOD PART OF CENTRAL PA AS THE
EARLIER MENTIONED MODERATION IN THE UPPER FLOW IS FORECAST TO
ARRIVE. THE NEXT SHORTWAVE TROF IS ALSO CURRENTLY TIMED FOR NEXT
WEEKEND...LEADING TO THE POSSIBILITY OF SNOW OR RAIN FOR A CHANGE
OVER SRN PA AND SNOW OVER THEN NORTH.
&&
.AVIATION /21Z MONDAY THROUGH SATURDAY/...
VFR WITH NO SIG WX CONDITIONS THROUGH LATE AFTERNOON.
LOW PRESSURE MOVING NEWD FROM AL OFF THE MID ATLC COAST OVERNIGHT
WILL SPREAD SNOW AND IFR CONDS ACROSS THE SRN 1/2 OF THE
AIRSPACE LATER THIS AFTERNOON AND OVERNIGHT. SNOW WILL BE QUICK-
HITTING AND END BY 12-15Z TUESDAY FROM WEST TO EAST. HIGHEST
CONFIDENCE IN IFR IS OVER THE SRN AIRFIELDS. USED A BLEND OF HIGH
RES MDLS FOR TIMING WITH SNOW ONSET 21-00Z SPREADING FROM SW TO
NE.
OUTLOOK...
WED-THU...MVFR/IFR -SHSN WRN 1/3. VFR/MVFR -SHSN CENTRAL/ERN 2/3
FRI...BCMG VFR. NO SIG WX.
SAT...MVFR WITH SNOW SHOWERS ASSOC WITH AN APPROACHING COLD FRONT.
&&
.CLIMATE...
MOST OF THE FORECAST AREA WAS ZERO OR COLDER LAST NIGHT WITH
CHANDLER`S VALLEY BEING THE COLDEST COMING IN AT -32.
HARRISBURG AND WILLIAMSPORT BOTH TIED THEIR RECORD LOWS FOR THE
DATE. HARRISBURG WAS 0 AND WILLIAMSPORT WAS -5.
RECORD LOWS/YEAR
HARRISBURG.............0/1905
WILLIAMSPORT..........-5/1905
STATE COLLEGE.........-8/1904
YORK..................-7/1963
ALTOONA...............-2/2004
BRADFORD..............-23/1943
CLEARFIELD............-6/1930
JOHNSTOWN.............-10/1943
LANCASTER.............+2/1987
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 7 AM EST
TUESDAY FOR PAZ024>028-033>036-056-057-059-063>066.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...LA CORTE
SHORT TERM...LA CORTE
LONG TERM...GARTNER/DEFLITCH
AVIATION...LA CORTE
CLIMATE...
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
206 PM EST MON FEB 16 2015
.SYNOPSIS...
LOW PRESSURE WILL TRACK SOUTH OF THE REGION TONIGHT AND EARLY
TUESDAY FOLLOWED BY ANOTHER BLAST OF ARCTIC AIR THAT WILL MOVE
INTO THE REGION FOR THE MID TO LATE WEEK PERIOD.
&&
.NEAR TERM /THROUGH TONIGHT/...
SATELLITE LOOP SHOWS CLOUDS CONTINUING TO INCREASE OVER THE REGION
WITH SURFACE OBS SHOWING THE NEAREST SNOW HITTING THE GROUND
MOVING INTO NORTHERN WV-WESTERN VA.
LATEST HRRR HAS LIGHT SNOW OVERSPREADING SWRN AREAS BETWEEN ABOUT
20-23Z POTENTIALLY IMPACTING THE EVENING COMMUTE.
LOOKING AT THE BEST LAYER FRONTOGENETIC FORCING FROM THE NEW NAM
SUGGESTS THE AXIS OF HEAVIEST SNOW WILL BE SOUTH OF THE PA-MD
BORDER...WITH PERHAPS FAR SRN LANCASTER-YORK COUNTIES PICKING UP
SLIGHTLY HIGHER AMOUNTS AS THE BEST WARM ADVECTION/FRONTOGENESIS
MOVES THROUGH OVERNIGHT.
SREF/GEFS SUPPORT CONFINING QPF OF HALF INCH OR MORE SOUTH OF THE
BORDER LEADING TO A HIGH CONFIDENCE OF A MAINLY LIGHT-MODERATE
SNOWFALL.
WILL CONTINUE THE WINTER WEATHER ADVISORY WITH NO PLANNED CHANGES
AT THIS POINT IN TIME...FOR THE SOUTHERN 2 LAYERS OF COUNTIES IN
OUR CWA. THE SOUTHERN TIER IS EXPECTED TO SEE BETWEEN 2 AND 5
INCHES OF SNOW BY THE MORNING COMMUTE TUESDAY...WHILE COUNTY-
LAYER WITHIN THE RT 22/322 CORRIDOR SHOULD SEE MORE ALONG THE
LINES OF 1-4 INCHES. LESSER AMOUNTS OF AROUND 1-2 INCHES ARE
ANTICIPATED TO FALL RIGHT ALONG INTERSTATE 80...WITH AN INCH OR
LESS ACROSS THE MTNS OF NRN PENN.
PRECIP WILL BE TAPERING OFF IN THE HOURS JUST AFTER MIDNIGHT OVER
MY SWRN ZONES WITH MOST OF THE SNOW HAVING ENDED EVEN IN THE EAST
BY AROUND SUNRISE.
OVERNIGHT LOWS WILL AVERAGE IN THE SINGLE DIGITS...TO PERHAPS THE
LOWER TEENS OVER THE SE.
&&
.SHORT TERM /TUESDAY/...
THE BROAD AREA OF WEAK TO MDT ASCENT ASSOCIATED WITH THE COUPLED
UPPER JET WILL SCOOT QUICKLY EAST OF THE REGION TUESDAY MORNING
FOLLOWED BY WEST-SOUTHWESTERLY FLOW IN THE LOW TO MID
LEVELS...ALLOWING FOR SOME PARTIAL CLEARING IN THE AFTERNOON.
I FOLLOWED MOS POPS MOST CLOSELY LEADING TO A MAINLY DRY DAY FCST
FOR MOST AREAS. THINKING IS THAT ANY LINGERING LIGHT SNOW SHOWERS
WILL BE CONFINED TO WESTERN HIGHER ELEVATIONS.
TEMPS DURING THE DAY TUESDAY WILL WARM BY ANOTHER 10 DEG COMPARED
TO TODAY`S HIGHS. IT`S PRETTY AMAZING THAT EVEN AFTER THE
UPCOMING 2 DAYS OF MODERATING TEMPS...HIGHS TUESDAY WILL STILL BE
15-20 DEG BELOW NORMAL FOR THE DATE.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
VERY COLD AIR WILL CONTINUE TO IMPACT THE REGION THROUGH AT LEAST
THE UPCOMING WORK-WEEK AS A STRONG UPPER LEVEL RIDGE REMAINS OVER
THE WESTERN U.S. AND CONTINUES TO DIRECT POLAR AIR INTO THE
EASTERN U.S. VIA PERSISTENT TROUGH.
SHORT WAVE ENERGY IS FORECAST TO CROSS THE INTO THE PAC LATE IN
THE WEEK AND DIG INTO THE FOUR CORNERS REGION AS THE UPPER RIDGE
REBUILDS NWD INTO WRN CANADA. THIS WILL SHIFT THE UPPER TROF AXIS
NOW COVERING THE EASTERN U.S. - WESTWARD. THIS IN TURN WILL LEAD
TO A FLATTENING OF THE UPPER FLOW OVER THE NORTHEAST NEXT WEEKEND
AND A MODERATION AWAY FROM THE BITTER COLD IN THE CURRENT PATTERN.
PRIOR TO THIS LATE WEEK...LARGE SCALE FLOW MODIFICATION WE`LL HAVE
TO DEAL WITH ONE MORE ARCTIC BLAST...THE LEADING EDGE OF WHICH
WILL PUSH ACROSS THE STATE DURING THE DAY WEDNESDAY. SOMEWHAT
SIMILAR TO SATURDAY...WE SEE A WELL-DEFINED AREA OF STEEP 850-500
MB LAPSE RATES AROUND...OR IN EXCESS OF 7C/KM THAT WILL MOVE
ACROSS THE WESTERN MTNS DURING THE EARLY TO MID AFTERNOON...AND
THROUGH THE SUSQ VALLEY EARLY WED EVENING. ALTHOUGH LIKELY NOT AS
EXTENSIVE AND CONSISTENTLY INTENSE OF A LINE THAT WE SAW SATURDAY
/COMPLETE WITH FEW FLASHES OF LIGHTNING IN SOME LOCATIONS/...THE
SQUALLS ASSOCIATED WITH THIS RIBBON OF INSTABILITY WED WILL LIKELY
COME IN THE FORM ONE OR TWO LINES...AND DUMP A QUICK .5 TO 1.5
INCHES OF SNOW - GREATLY IMPACTING TRAVEL FOR A SHORT PERIOD.
BEHIND THIS SYSTEM YET ANOTHER SURGE OF EXTREMELY COLD AIR WILL
SURGE ACROSS THE STATE FOR THE SECOND HALF OF THE WEEK.
SIMILAR...EXTREMELY COLD TEMPS AT 850 MB ARE FORECAST TO MOVE OVER
THE STATE THURSDAY AND FRIDAY /AND COULD BE EVEN A FEW DEG C LOWER
THAN THOSE ASSOCIATED WITH THIS PAST SUNDAY-MONDAY ARCTIC
AIRMASS/. 03Z SREF SHOWS MEAN 850 TEMPS OF -25 TO -28C COVERING
ALL OF CENTRAL PENN WHICH IS ABOUT -3 SIGMA. HIGH TEMPS THURSDAY
MAY STAY A FEW-SVRL DEG F BELOW ZERO AGAIN ACROSS THE NRN
MTNS...AND HOLD IN THE SINGLE DIGITS TO LOWER TEENS ACROSS THE
REST OF CENTRAL AND SRN PENN...BEFORE MODERATING BY 5-7 DEG
FRIDAY. MORNING LOWS THURSDAY AND FRIDAY COULD RIVAL THOSE OF
SUNDAY AND MONDAY MORNING.
THE CENTER OF THIS NEXT ARCTIC HIGH MAY SLIDE JUST SOUTH OF THE
REGION THEN OFF THE MID ATLANTIC COAST - PER THE 00Z EC...WHILE
THE GEFS WOULD SUGGEST A LITTLE MORE IN THE WAY OF LLVL COLD AIR
DAMMING OVER THE CWA...PRECEDING INCREASING MOISTURE AND A WINTRY
MIX OR SNOW SPREADING IN FROM THE SW...THEN ANOTHER PUSH OF
ARCTIC AIR FOR LATE SUNDAY AND MONDAY.
TEMPERATURES NEXT SUNDAY...HOWEVER...HOLD THE POTENTIAL TO RISE
ABOVE THE FREEZING MARK OVER A GOOD PART OF CENTRAL PA AS THE
EARLIER MENTIONED MODERATION IN THE UPPER FLOW IS FORECAST TO
ARRIVE. THE NEXT SHORTWAVE TROF IS ALSO CURRENTLY TIMED FOR NEXT
WEEKEND...LEADING TO THE POSSIBILITY OF SNOW OR RAIN FOR A CHANGE
OVER SRN PA AND SNOW OVER THEN NORTH.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
VFR WITH NO SIG WX CONDITIONS THROUGH LATE AFTERNOON.
LOW PRESSURE MOVING NEWD FROM AL OFF THE MID ATLC COAST OVERNIGHT
WILL SPREAD SNOW AND IFR CONDS ACROSS THE SRN 1/2 OF THE
AIRSPACE LATER THIS AFTERNOON AND OVERNIGHT. SNOW WILL BE QUICK-
HITTING AND END BY 12-15Z TUESDAY FROM WEST TO EAST. HIGHEST
CONFIDENCE IN IFR IS OVER THE SRN AIRFIELDS. USED A BLEND OF HIGH
RES MDLS FOR TIMING WITH SNOW ONSET 21-00Z SPREADING FROM SW TO
NE.
OUTLOOK...
WED-THU...MVFR/IFR -SHSN WRN 1/3. VFR/MVFR -SHSN CENTRAL/ERN 2/3
FRI...BCMG VFR. NO SIG WX.
SAT...MVFR WITH SNOW SHOWERS ASSOC WITH AN APPROACHING COLD FRONT.
&&
.CLIMATE...
MOST OF THE FORECAST AREA WAS ZERO OR COLDER LAST NIGHT WITH
CHANDLER`S VALLEY BEING THE COLDEST COMING IN AT -32.
HARRISBURG AND WILLIAMSPORT BOTH TIED THEIR RECORD LOWS FOR THE
DATE. HARRISBURG WAS 0 AND WILLIAMSPORT WAS -5.
RECORD LOWS/YEAR
HARRISBURG.............0/1905
WILLIAMSPORT..........-5/1905
STATE COLLEGE.........-8/1904
YORK..................-7/1963
ALTOONA...............-2/2004
BRADFORD..............-23/1943
CLEARFIELD............-6/1930
JOHNSTOWN.............-10/1943
LANCASTER.............+2/1987
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 7 AM EST
TUESDAY FOR PAZ024>028-033>036-056-057-059-063>066.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...LA CORTE
SHORT TERM...LA CORTE
LONG TERM...LAMBERT/GARTNER
AVIATION...LA CORTE
CLIMATE...LA CORTE
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
106 PM EST MON FEB 16 2015
.SYNOPSIS...
A MOIST LOW PRESSURE SYSTEM WITH WIDESPREAD WINTRY PRECIPITATION
WILL TRACK ACROSS THE CAROLINAS TONIGHT AND MOVE OFF THE MID
ATLANTIC COAST TUESDAY MORNING. IN ITS WAKE...AN ARCTIC COLD FRONT
WILL SWEEP THROUGH FROM THE NORTH WEDNESDAY. VERY COLD HIGH
PRESSURE WILL THEN BUILD IN AND PERSIST THROUGH FRIDAY...BEFORE A
MOIST SURFACE BOUNDARY MOVES INTO THE AREA OVER THE WEEKEND.
&&
.NEAR TERM /THROUGH TUESDAY/...
AS OF 1255 PM EST...THE UPPER LEVEL SHORTWAVE MOVING FROM THE SRN
PLAINS TO THE MID MS RIVER VALLEY TODAY WILL DAMPEN AS IT MOVES
EASTWARD ACROSS THE APPALACHIANS LATER TONIGHT. THE ASSOCIATED SFC
LOW CENTER MOVING ACROSS THE DEEP SOUTH SHOULD TRACK FROM THE
CENTRAL AL/GA BORDER AT 00Z THIS EVENING...TO NW OF AUGUSTA GA BY
06Z...TO OFF THE OUTER BANKS OF NC BY 12Z TUE. AHEAD OF THIS
LOW...PRECIPITATION IS RAPIDLY FILLING IN FROM THE WEST THIS
AFTN...AND THERMAL PROFILES ARE QUICKLY WET BULBING DOWN TO SUPPORT
MAINLY SNOW/SLEET SHORTLY AFTER ONSET. THE DEEPER FORCING WILL REACH
THE FORECAST AREA FROM THE W STEADILY THROUGH THE LATE AFTN
HOURS...MAXIMIZING 00Z TO 03Z AS THE BEST SRLY JET TRAVERSES THE
REGION. THE LATEST RAP RUN HAS REGAINED IT/S THERMAL SANITY
SOMEWHAT...WITH SUBFREEZING SFC TEMPS NOW LARGELY LOCKED IN ALONG
AND NW OF INTERSTATE 85 UNTIL MID TO LATE EVENING. THE MAIN
EXCEPTION WILL BE IN WRN/SRN UPSTATE SECTIONS AS WELL AS NE GA
OUTSIDE OF THE MTNS...WHERE THE SREF MEAN/GEFS ALSO SUPPORT EARLIER
WARMING OF SFC TEMPS. THIS WILL MAKE FOR A VERY SHARP ICE ACCUM
GRADIENT IN THE SRN TIER...BUT THE CURRENT HAZARD SUITE SEEMS TO
HAVE THIS FAIRLY WELL PLACED.
LOCATIONS NW OF INTERSTATE 40 LOOK TO BE MORE SOLIDLY SNOW
THROUGHOUT THE VAST MAJORITY OF THE EVENT...WITH SOME SLEET ONLY
MIXING IN AT TIMES EARLY AND LATE...AND ANY FZRA WINDOW FAIRLY
BRIEF. NRN BLUE RIDGE AREA SNOW ACCUMS HAVE BEEN BOOSTED SLIGHTLY.
EXPECT SOME DRY SLOTTING TO ARRIVE AT MID LEVELS CIRCA 06Z TO
09Z...WITH POPS TRENDING DOWN WEST TO EAST LATE TONIGHT. NW FLOW
MOISTURE WILL DIMISH ALONG THE SPINE OF THE SRN APPALACHIANS TUE
MORNING...WITH LOW LEVEL FLOW BACKING AHEAD OF THE FALLING HEIGHTS
TO THE W AS A DEEP CENTRAL CONUS TROUGH TRANSITIONS EWD. MELTING IS
LIKELY IN THE SRN MTNS AND ACROSS THE FOOTHILLS/PIEDMONT TUE
AFTN...TEMPS REBOUNDING ABOVE FREEZING IN WEAK WESTERLY DOWNSLOPE
FLOW.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/...
AS OF 300 AM MONDAY...THE 00Z MODELS ARE IN VERY GOOD AGREEMENT ON
THE BACK EDGE OF THE PRECIP SHIELD PRETTY MUCH COMPLETELY EXITED OFF
TO THE EAST BY 12Z TUESDAY...EXCEPT FOR SOME LINGER NW FLOW CHCS FOR
TUESDAY MORNING. OTHERWISE...TUESDAY LOOKS LIKE A COLD DAY...WITH
PERSISTENT 850 MB CAA ALL DAY. TEMPS DO REBOUND FROM SUN-MON
READINGS...BUT STILL 10-15 DEG BELOW NORMAL (20S TO UPR 30S MTNS AND
MAINLY LWR-MID 40S PIEDMONT).
TUESDAY NIGHT THRU WEDNESDAY NIGHT...ANOTHER PIECE OF THE POLAR
VORTEX WILL DIG INTO THE GREAT LAKES...AND BRING TWO SHOTS OF
REINFORCING ARCTIC AIR. THE FIRST WILL BE WEDNESDAY MORNING...WITH
STRONG CAA AND SOME LLVL MOISTURE FOR NW FLOW SNOW SHWR ACTIVITY.
THE SECOND (STRONGER) FRONT WILL CROSS THE AREA WEDNESDAY NIGHT. THE
MAIN CONCERN WITH THE FIRST FRONT WILL BE SNOW ALONG THE TN BORDER.
GUIDANCE HAS TRENDED A LITTLE WETTER...BUT LIKE THE LAST FEW FRONTS
OF THIS NATURE...THE TIME INTERVAL IS RATHER SHORT...AND GENERALLY
SUB-ADV ACCUMS ARE EXPECTED. I DID BUMP UP POP FOR WEDNESDAY IN THE
NC MTNS. THE OP MODELS AGREE ON STEEP LLVL LAPSE RATES ACRS THE
PIEDMONT WITH AT LEAST A SLGT CHC OF A FEW SHWRS BREAKING
CONTAINMENT FROM THE TN LINE WED AFTN. I INTRODUCED A SLGT CHC OF
SNOW SHWRS ACRS THE NC PIEDMONT. NO ACCUMS EXPECTED...BUT AN ISOLD
DUSTING LOOKS POSSIBLE. TEMPS WEDNESDAY WILL BE 2-3 CATEGORIES
COLDER THAN TUESDAY. WITH THE SECOND FRONT WEDNESDAY NIGHT...THE
BIGGER CONCERN WILL BE WIND CHILLS. THE 850 MB TEMPS PLUMMET TO -17
TO -24C ACRS MOST OF THE CWFA. WITH STILL DECENT WINDS OF 30-40 KTS
AT 850 MB AND CAA...SHUD SEE GUSTY WINDS LINGERING OVERNIGHT IN THE
MTNS AND A LIGHT WIND ACRS THE PIEDMONT. THIS COUPLED WITH LIKELY
RECORD LOW TEMPS THURSDAY MORNING WILL RESULT IN SOLID WIND CHILL
ADV CRITERIA ACRS NEARLY THE ENTIRE CWFA...AND WIND CHILL WARNING
ACRS ALL THE NC MTNS ABOVE 3500 FT. WILL HIGHLIGHT DANGEROUS WIND
CHILLS IN THE HWO. FOR THE DAILY RECORD LOWS FOR THURSDAY SEE
CLIMATE SECTION BELOW.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 255 AM MONDAY...ONLY A FEW CHANGES WERE MADE THE PREVIOUS FCST
AS GUIDANCE CONTINUES TO SHOW UNCERTAINTY WITH THE EVOLUTION OF THE
SRN STREAM SFC BNDRY AND DEGREE/PLACEMENT OF SFC CYCLOGENESIS. THERE
SHOULD BE A GOOD AMOUNT OF GOM MOISTURE FLUX AFT THU BUT AGAIN...AN
AGREEABLE AREA OF LIKELY PRECIP REMAINS TO BE WORKED OUT.
WITH A VERY COLD START TO THE DAY THU AND A CA HIGH CENTER WORKING
ACROSS TN...MAX TEMPS WILL RECOVER ONLY NOMINALLY EVEN WITH VERY
GOOD INSOL. RECORD LOW MAXES ARE STILL FCST/D BY A FEW DEGREES. THU
NIGHT AND FRI WILL REMAIN QUITE COLD AS THE SFC HIGH SHIFTS EAST
ACROSS SRN VA AND ENABLES GOOD RAD COOLING AND A SLOWLY VEERING FLOW.
THUS...MINS AND MAXES WILL AGAIN APPROACH AND POSSIBLY BREAK RECORD
LEVELS. SEE THE CLIMATE SECTION OF THIS AFD FOR THE ACTUAL RECORD
VALUES. VERY COLD WIND CHILLS WILL DEVELOP THU NIGHT ACROSS THE
FCST AREA...WITH THE NC MTNS LIKELY REACHING WARNING/ADV CRITERIA
THROUGH DAYBREAK.
THE PATTERN REMAINS ACTIVE FRI THROUGH THE WEEKEND. HOWEVER...MORE
UNCERTAINTY ARISES...WITH THE OP MODELS CONTINUING TO SHOW DISPARATE
HANDLINGS WRT THE SRN BNDRY AND INTERACTIONS WITH ULVL S/W ENERGY.
THE LATEST TREND HAS BEEN FOR A SLOWER ADVANCEMENT EAST WITH
MEASURABLE PRECIP FRI AS A STUBBORN CA HIGH PERSISTS OVER THE
CAROLINAS. THE ECMWF HAS MORE RIDGING ALOFT AND THIS KEEPS IT/S SFC
BNDRY MORE NORTH AND WEST THAN THE GFS THROUGH THE PERIOD. SO...POPS
WERE ADJ DOWN A LITTLE ACCOUNT FOR HIGHER UNCERTAINTY MAINLY ACROSS
THE SRN ZONES. PRECIP SHOULD BE MAINLY DIURNAL RAIN/SNOW...WITH SOME
LOW SNOW ACCUMS POSSIBLE OUTSIDE THE MTNS FRI NIGHT AND AGAIN
NON/MTN -SNSH POSSIBLE SAT NIGHT OVER THE NRN ZONES. MAX TEMPS
SHOULD WARM 8-10 DEGREES BOTH SAT AND SUN...YET STILL A COUPLE
DEGREES BELOW NORMAL SUN AFTERNOON.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
AT KCLT...RADAR SHOWS THE LIGHT VIRGA/PRECIP SHIELD JUST WEST OF
KGSP AT ISSUANCE TIME...WITH A LIGHT SN/PL ONSET LIKELY BY 21Z AT
KCLT. EXPECT MVFR CIGS TO QUICKLY SET UP...WITH A STEADY TRANSITION
TO FZRA FOR THE BULK OF THE PRECIP EVENT TONIGHT. ICE ACCUMULATIONS
OF ONE QUARTER TO ONE THIRD INCH TONIGHT WILL POSE MAJOR DEICING
ISSUES FOR THE AIRFIELD WITH MIN TEMPS BELOW FREEZING UNTIL MID
MORNING TUE. EXPECT IFR TO LIFR CIGS DURING THE HEAVIEST
PRECIP...WITH ONLY SLOW RECOVERY THROUGH TUE MORNING. ESE WINDS
EARLY WILL QUICKLY TOGGLE NE AS THE PRECIPITATION GETS
STARTED...WITH MORE LIGHT N TO NW FLOW ON TUE AS CIGS SLOWLY LIFT
AND SCATTER.
ELSEWHERE...THE LEADING EDGE OF THE PRECIP SHIELD WAS FROM KAVL TO
KGSP TO KAND AT ISSUANCE TIME...WITH MAINLY SNOW/SLEET AT ONSET.
KAND WILL TRANSITION TO RAIN THE QUICKEST THIS EVENING...WHILE
KGSP/KGMU GET MORE LOCKED IN WITH FZRA FOR MUCH OF THE LATE
DAY/EVENING HOURS. KAVL WILL SEE MORE SNOW/SLEET FOR A LONGER
PERIOD...BEFORE THE FZRA WINDOW OPENS THERE LATE EVENING. KHKY WILL
ALSO SEE A MUCH LONGER SNOW/SLEET WINDOW...WITH LARGER ACCUMS
POSSIBLE THAN AT THE OTHER SITES...AND SLIGHTLY LESS FZRA. ALL
TOLD...MOST OF THE SITES WILL HAVE SIGNIFICANT DEICING
ISSUES...ASIDE FROM POSSIBLY KAND WHERE RAIN IS MORE LIKELY. EXPECT
CIGS TO TRANSITION DOWN QUICKLY THROUGH MVFR LATE TODAY...WITH IFR
TO LIFR LIKELY DURING THE PERIOD OF HEAVIEST PRECIPITATION THIS
EVENING/OVERNIGHT. SLOW LIFTING AND SCATTERING IS EXPECTED THROUGH
TUE MORNING.
OUTLOOK...A WEAK WAVE WILL MOVE THROUGH THE REGION ON WED...BUT
CONDITIONS LOOK TO BE MAINLY VFR. VERY COLD WEATHER WILL RETURN
THROUGH LATE WEEK.
CONFIDENCE TABLE...
13-19Z 19-01Z 01-07Z 07-12Z
KCLT HIGH 95% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL MED 74% HIGH 100% HIGH 100% HIGH 100%
KHKY MED 77% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY
EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS
ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.CLIMATE...
RECORD MINIMUM TEMPERATURES FOR THURSDAY...FEBRUARY 19TH...
GSP 9 1958
CLT 8 1958
AVL 7 1958
RECORD LOW MAXIMUM TEMPERATURES FOR THURSDAY...FEBRUARY 19TH...
GSP 30 1900
CLT 34 1958
AVL 25 1958
RECORD MINIMUM TEMPERATURES FOR FRIDAY...FEBRUARY 20TH...
GSP 13 1903
CLT 13 1896
AVL 10 1979
RECORD LOW MAXIMUM TEMPERATURES FOR FRIDAY...FEBRUARY 20TH...
GSP 34 1947
CLT 32 1947
AVL 26 1979
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...WINTER STORM WARNING UNTIL 7 AM EST TUESDAY FOR GAZ010-017.
WINTER WEATHER ADVISORY UNTIL 7 AM EST TUESDAY FOR GAZ018.
NC...WINTER STORM WARNING UNTIL 7 AM EST TUESDAY FOR NCZ033-035>037-
048>053-056>059-062>065-068>072-082-501>510.
SC...WINTER STORM WARNING UNTIL 7 AM EST TUESDAY FOR SCZ001>003-
005>009.
WINTER WEATHER ADVISORY UNTIL 7 AM EST TUESDAY FOR SCZ004-010-
012>014.
&&
$$
SYNOPSIS...DEO
NEAR TERM...HG
SHORT TERM...ARK
LONG TERM...SBK
AVIATION...HG
CLIMATE...
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
343 PM CST MON FEB 16 2015
.DISCUSSION...
LIGHT RAIN CONTINUES ACROSS OUR SOUTHEAST COUNTIES THIS AFTERNOON
BUT SHOULD MOVE OUT OF THE REGION BY SUNSET. TEMPERATURES IN THIS
AREA HAVE STAYED ABOVE FREEZING AND EXPECT ALL RAIN TO REMAIN IN
LIQUID FORM THROUGH THE REMAINDER OF THE AFTERNOON HOURS. A
RELATIVELY DRY EVENING AND NIGHT IS EXPECTED BUT THERE STILL
REMAINS A LOW CHANCE FOR LIGHT SNOW OR SNOW FLURRIES OVER THE
REGION LATE TONIGHT AND TUESDAY MORNING.
BROAD UPPER LEVEL TROUGHING CONTINUES ACROSS THE REGION THIS
AFTERNOON. A DISTURBANCE...CURRENTLY MOVING ACROSS UTAH...WILL
CONTINUE SOUTHEAST INTO WEST TEXAS LATE TONIGHT AND THEN MOVE
ACROSS NORTH TEXAS DURING THE DAY ON TUESDAY. THIS DISTURBANCE IS
EXPECTED TO GENERATE ENOUGH MID LEVEL LIFT TO PRODUCE SNOW ACROSS
WEST TEXAS TONIGHT WITH POSSIBLY A BAND OF LIGHT SNOW OCCURRING
ACROSS THE WESTERN COUNTIES OF NORTH TEXAS. FORECAST SOUNDINGS
CONTINUE TO INDICATE THE LOWER LEVELS OF THE ATMOSPHERE WILL
REMAIN DRY MAKING IT DIFFICULT FOR MUCH OF THE SNOW TO REACH THE
GROUND. THE FURTHER EAST YOU GO...THE DEEPER THE DRY LAYER AT THE
SURFACE. WILL KEEP A SLIGHT CHANCE FOR SNOW ALONG AND WEST OF A
LINE FROM BRIDGEPORT TO WEATHERFORD TO KILLEEN OVERNIGHT TONIGHT
AND TUESDAY MORNING. DO NOT THINK ALL OF THIS AREA WILL SEE
SNOW...BUT AM NOT SURE EXACTLY WHERE THE BAND OF SNOW WILL OCCUR.
MOST OF THE HI-RES GUIDANCE SUGGESTS IT MAY OCCUR NEAR OR NORTH OF
I-20. A TRACE OF SNOW ACCUMULATION MAY OCCUR ON GRASS UNDERNEATH
THE SNOW BAND BUT NO IMPACTS ARE EXPECTED FROM ANY SNOW THAT DOES
FALL. EAST OF THIS AREA...WILL KEEP A MENTION FOR FLURRIES WITH A
LESS THAN 20 POP.
DURING THE AFTERNOON AND EARLY EVENING HOURS OF TUESDAY...BOTH THE
TEXAS TECH WRF AND NAM SUGGEST SOME LIGHT RAIN OR DRIZZLE MAY
OCCUR IN OUR NORTHWEST AND/OR NORTH COUNTIES AS THE DISTURBANCE
EXITS THE REGION...BUT THINK WITH THE NEAR-SURFACE DRY LAYER IT
WILL STILL BE DIFFICULT FOR ANY PRECIP TO REACH THE GROUND. IF
ANYTHING DOES REACH THE GROUND...SOUNDINGS INDICATE IT WOULD
REMAIN AS LIQUID RAIN OR DRIZZLE. FOR NOW...WILL KEEP A 10 POP BUT
NOT MENTION ANY RAIN OR DRIZZLE IN THE WORDED FORECAST.
FOR THE REMAINDER OF THE WORK WEEK...WE WILL REMAIN UNDER
NORTHWEST FLOW ALOFT WITH A LARGE UPPER LEVEL TROUGH SLOWLY MOVING
EAST OVER THE EASTERN HALF OF THE CONUS. A WEAK FRONT WILL MOVE
INTO AT LEAST THE EASTERN HALF OF THE CWA ON WEDNESDAY BUT IT WILL
HARDLY BE NOTICED EXCEPT FOR A WIND SHIFT TO THE NORTH.
TEMPERATURES WILL STEADILY WARM THROUGH FRIDAY. RAIN CHANCES
RETURN TO THE FORECAST ON THURSDAY NIGHT AND FRIDAY AS WARM AIR
ADVECTION ALLOWS FOR SOME LIGHT RAIN OVER MAINLY THE EASTERN HALF
OF THE CWA.
BEGINNING ON FRIDAY...A POSITIVELY-TILTED AND NEARLY ZONAL TROUGH
WILL BEGIN TO DEVELOP ALONG THE WEST COAST. AS THIS DEVELOPS...IT
WILL SEND A STRONGER COLD FRONT INTO THE REGION THIS WEEKEND. THE
GEM AND ECMWF ARE IN FAIRLY GOOD AGREEMENT THAT THE FRONT WILL
ARRIVE SATURDAY AND SATURDAY NIGHT WHILE THE GFS STALLS THE FRONT
JUST NORTH OF THE AREA. HOWEVER...IN PREVIOUS MODEL RUNS THE GFS
BROUGHT THE FRONT THROUGH THE AREA THIS WEEKEND. THIS FORECAST
WILL LEAN MORE TOWARDS THE CONSENSUS OF THE ECMWF AND GEM WITH THE
FRONT ARRIVING ON SATURDAY. THERE WILL BE A CHANCE FOR RAIN AND
ISOLATED THUNDERSTORMS WITH THE FRONT ON SATURDAY AND SATURDAY
NIGHT. DEPENDING ON WHAT THE UPPER LEVEL PATTERN EVENTUALLY
EVOLVES INTO...THERE COULD BE LINGERING PRECIP CHANCES THROUGH
THE REMAINDER OF THE WEEKEND AND INTO EARLY NEXT WEEK. THE ECMWF
SOUNDINGS SUGGEST THAT THE ATMOSPHERIC PROFILES WILL BE COLD ENOUGH
FOR POSSIBLY SOME SNOW. WILL MENTION A RAIN/SNOW MIX ACROSS THE
NORTHERN HALF OF THE REGION SUNDAY NIGHT AND MONDAY BUT THIS
POTENTIAL EVENT IS STILL 6-8 DAYS OUT AND THERE ARE LIKELY TO BE
CHANGES TO THE FORECAST BEFORE THEN.
82/JLD
&&
.AVIATION...
/ISSUED 1252 PM CST MON FEB 16 2015/
FOR THE 18Z TAFS...MVFR CIGS ARE EXPECTED TO REMAIN IN PLACE
THROUGH THIS EVENING. ON AND OFF LIGHT RAINFALL WILL CONTINUE
AROUND CENTRAL TEXAS THROUGH THE MID-AFTERNOON HOURS...WITH
TEMPERATURES HOVERING AROUND OR JUST ABOVE FREEZING FOR WACO.
A SUFFICIENT AMOUNT OF LOW-LEVEL DRY AIR SEEMS TO HAVE ADVECTED
ACROSS NORTH TEXAS TO PREVENT ANY PRECIPITATION FROM REDEVELOPING
OVER DFW AREA AIRPORTS. A WEAK UPPER LEVEL DISTURBANCE OVER FAR
WEST TEXAS WILL MOVE NORTHEAST THROUGH THIS AFTERNOON PROVIDING
PERSISTENT LIFT OVER CENTRAL TEXAS FOR ON AND OFF LIGHT RAIN. FOR
THE WACO TAF...THE CURRENT TEMPERATURE WAS 33 DEGREES...AND THE
TEMPERATURE IS UNLIKELY TO CHANGE SIGNIFICANTLY OVER THE NEXT FEW
HOURS. AS A RESULT...HAVE SIMPLY LEFT A MENTION OF LIGHT RAIN IN
THE FORECAST WITH MVFR CIGS THROUGH THIS AFTERNOON FOR KACT.
LEFT MVFR CIGS IN PLACE WITH NO MENTION OF PRECIPITATION ACROSS
ALL OF THE DFW AREA TAF SITES THROUGH THIS EVENING. LINGERED MVFR
CIGS IN PLACE LONGER THAN THE PREVIOUS FORECAST DUE TO THE LATEST
FORECAST SOUNDINGS FROM THE HRRR WHICH SEEMS TO BE HANDLING
CURRENT CONDITIONS FAIRLY ACCURATELY. DRY AIR ADVECTION AND MID-
LEVEL SUBSIDENCE ARE EXPECTED ACROSS THE ENTIRE REGION THIS
EVENING...WHICH SHOULD ALLOW LOW CLOUDS TO SCATTER OUT JUST
LEAVING VFR CLOUDS IN PLACE.
A SECOND UPPER LEVEL DISTURBANCE WILL SPREAD LIFT OVER THE REGION
EARLY TOMORROW MORNING. THE LIFT IS FAIRLY STRONG WITH THIS
DISTURBANCE...HOWEVER THE LOW-LEVEL ATMOSPHERE IS EXPECTED TO
REMAIN QUITE DRY. AS A RESULT...THINK THAT WE WILL HAVE SNOW
GENERATED FROM CLOUDS BASED AT NEAR THE 700 MB LEVEL...OR 9000 FT
AGL. BELOW THE 700 MB LEVEL...DRY AIR IS EXPECTED TO PREVENT MOST
OF THIS SNOW FROM REACHING THE GROUND. AS A RESULT...LEFT SNOW OUT
OF THE FORECAST FOR TOMORROW MORNING FOR ALL AREA TAF SITES. WILL
CONTINUE TO WATCH LOW-LEVEL MOISTURE PROFILES CLOSELY
OVERNIGHT...HOWEVER ALL MODEL GUIDANCE INDICATES THIS DRY AIR WILL
BE IN PLACE...SO DO NOT SEE MUCH MORE THAN FLURRIES MAKING IT
THROUGH 8-9000 FEET OF DRY AIR BELOW THE SNOW GENERATING CLOUDS.
CAVANAUGH
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 27 50 32 57 33 / 10 10 5 0 0
WACO, TX 27 49 31 61 34 / 10 10 5 0 0
PARIS, TX 22 46 27 50 26 / 10 10 10 0 0
DENTON, TX 26 51 30 56 31 / 10 10 10 0 0
MCKINNEY, TX 26 49 29 53 29 / 10 10 10 0 0
DALLAS, TX 29 50 34 57 34 / 10 10 5 0 0
TERRELL, TX 28 48 32 56 30 / 10 10 5 0 0
CORSICANA, TX 28 48 32 58 33 / 10 10 5 0 0
TEMPLE, TX 29 50 32 63 35 / 10 10 5 0 0
MINERAL WELLS, TX 29 51 31 59 32 / 20 20 5 0 0
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
69/82
AREA FORECAST DISCUSSION
NWS BROWNSVILLE TX
316 PM CST MON FEB 16 2015
.SHORT TERM /NOW THROUGH TUESDAY NIGHT/...A STRONG COLD FRONT
EXTENDING CURRENTLY FROM NEAR RIO GRANDE CITY TO NEAR BAFFIN BAY
WITH A PRE FRONTAL TROUGH AHEAD OF THE FRONT...ACROSS THE UPPER
PORTIONS OF THE RIO GRANDE VALLEY. WEST TO SOUTHWEST WINDS BETWEEN
2 TO 4K FEET MIXING DOWN TO THE SURFACE ALONG WITH FULL SUNSHINE HAS
ALLOWED TEMPERATURES TO SPIKE INTO THE LOW TO MID 80S ACROSS THE
VALLEY. BASED ON THE LATEST NAM/RAP AND HRRR DATA...THE STRONG FRONT
IS EXPECTED TO MOVE THROUGH MCALLEN AND HARLINGEN BETWEEN 4 AND 5
PM...BROWNSVILLE BETWEEN 5 AND 6 PM AND OFF THE LOWER TEXAS COAST
AROUND 7 PM. A DRASTIC CHANGE TO TEMPERATURES...BREEZY NORTH
WINDS...INCREASING LOW CLOUDINESS AND A POSSIBLE LIGHT SHOWER WILL
ACCOMPANY THE SHARP FROPA. TEMPERATURES WILL CONTINUE TO DROP
THROUGH THE EVENING WITH OVERNIGHT LOW TEMPERATURES IN THE 40S UNDER
MOSTLY CLOUDY SKIES. A MID TO UPPER LEVEL DISTURBANCE WILL MOVE
OVERHEAD TONIGHT. THIS FEATURE WILL SUPPORT ISOLATED TO SCATTERED
SHOWERS ACROSS THE REGION TONIGHT AND MAY LINGER ALONG THE COAST
INTO THE GULF WATERS TUESDAY MORNING.
SURFACE HIGH PRESSURE WILL BUILD ACROSS DEEP SOUTH TEXAS ON TUESDAY.
SKIES WILL GRADUALLY CLEAR BY TUESDAY AFTERNOON WITH TEMPERATURES
REMAINING WELL BELOW NORMAL. HIGH TEMPERATURES ON TUESDAY WILL BE IN
THE MID TO UPPER 50S WITH A FEW 60S POSSIBLE ACROSS THE WESTERN AREA
WITH MODERATE NORTH TO NORTHEAST WINDS. SURFACE HIGH PRESSURE
SETTLES ACROSS THE AREA TUESDAY NIGHT. CLEAR SKIES...DRY AIR AND
LIGHT WINDS WILL ALLOW FOR GOOD RADIATIONAL COOLING TUESDAY NIGHT.
OVERNIGHT LOW TEMPERATURES TUESDAY NIGHT EXPECTED TO FALL INTO THE
UPPER 30S ACROSS THE NORTHERN RANCHLANDS...LOWER 40S ACROSS THE RIO
GRANDE VALLEY AND THE MID 40S ALONG THE BEACHES.
.LONG TERM /WEDNESDAY THROUGH MONDAY/...500 MB RIDGING WILL
BUILD OVER DEEP SOUTH TX STARTING WEDNESDAY CONTINUING INTO FRIDAY
WHICH WILL ALLOW THE 1000-500 MB THICKNESSES TO INCREASE WITH A
PERSISTENT S-SE SURFACE FLOW BRINGING IN STEADY WAA AT THE LOW
LEVELS. THIS WILL ALLOW TEMPS TO STEADILY INCREASE THROUGH THE END
OF THIS WEEK. AS THE WEEKEND APPROACHES THE 500 MB RIDGE WILL BE
ERODED STEADILY AS A SERIES OF STRONG SHORT WAVES CARVE OUT A
BROAD 500 MB TROUGH OVER THE NORTHERN HALF OF THE LOWER 48 STATES.
AS THIS 500 MB TROFFING DEEPENS A COLD FRONT WILL BE PUSHED
TOWARDS DEEP SOUTH TX ON SUN.
THE ECMWF AND GFS ARE IN GOOD AGREEMENT IN THE OVERALL PLACEMENT
OF THE 500 MB FEATURES THROUGH FRI. THE MODELS THEN START TO
DIVERGE STEADILY FROM SAT THROUGH MON WITH THE ECMWF DIGGING A
DEEPER 500 MB TROUGH AXIS OVER THE LOWER 48 STATES VERSUS THE GFS.
THE GFS KEEPS THE 500 MB TROUGH AXIS MORE ELONGATED FROM THE WEST
COAST UP THROUGH THE GREAT LAKES WHICH KEEPS THE COLD FRONT FROM
PUSHING THROUGH THE RGV.
MOISTURE ADVECTION AHEAD OF THIS NEXT POTENTIAL FROPA IS NOT THE
GREATEST IN THE WORLD SO WILL HOLD THE POPS AROUND 20 % LATE IN
THE FORECAST PERIOD UNTIL THE MODELS RESOLVE THEMSELVES A BIT
BETTER.
WILL LEAN MORE TOWARDS THE ECMWF SOLUTION THROUGH DAY 7 FOR TEMPS.
OVERALL CONFIDENCE IN THE FORECAST IS PRETTY GOOD THROUGH FRI THEN
STARTS TO DROP FOR THE SAT THROUGH MON PERIOD DUE TO THE ECMWF AND
GFS DIVERGENCE LATE IN THE PERIOD.
&&
.MARINE...NOW THROUGH TUESDAY NIGHT...LIGHT SOUTH TO SOUTHWEST WINDS
WILL CONTINUE ALONG THE LOWER TEXAS COASTAL FOR THE NEXT FEW HOURS.
A STRONG COLD FRONT WILL MOVE FROM NORTH TO SOUTH ACROSS THE MARINE
AREA. WINDS WILL QUICKLY SHIFT TO THE NORTH TO NORTHWEST WITH GUSTY
WINDS. A SMALL CRAFT ADVISORY IS IN EFFECT FOR ALL OF THE LOWER
TEXAS COASTAL WINDS DUE TO VERY STRONG WINDS WITH ROUGH SEAS ON THE
GULF. MARINE CONDITIONS GRADUALLY IMPROVE TUESDAY EVENING INTO
WEDNESDAY AS HIGH PRESSURE SETTLES ACROSS THE AREA.
WEDNESDAY THROUGH SATURDAY...A MODERATE TO STRONG S-SE WINDS WILL
PREVAIL IN THE LONGER RANGE MARINE FORECAST PERIOD AS BROAD
SURFACE RIDGING REMAINS IN PLACE OVER THE GULF OF MEX. THE PGF
TIGHTENS UP ENOUGH FROM LATE THURS THROUGH SATURDAY TO POSSIBLY
RESULT IN SOME SCA FOR THE GULF WATERS.
&&
.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL 48 56 45 66 / 30 20 0 0
BROWNSVILLE 47 57 44 67 / 30 20 0 0
HARLINGEN 46 57 42 67 / 30 20 0 0
MCALLEN 47 60 42 68 / 20 10 0 0
RIO GRANDE CITY 47 60 41 69 / 20 10 0 0
SOUTH PADRE ISLAND 51 56 52 64 / 40 30 0 0
&&
.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT ADVISORY FOR WINDS UNTIL 3 AM CST TUESDAY FOR GMZ130-
132-135.
SMALL CRAFT ADVISORY UNTIL 6 PM CST TUESDAY FOR GMZ150-155-170-
175.
&&
$$
THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV
SHORT TERM...63
LONG TERM...60
GRAPHICAST/UPPER AIR...65
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
1252 PM CST MON FEB 16 2015
.AVIATION...
FOR THE 18Z TAFS...MVFR CIGS ARE EXPECTED TO REMAIN IN PLACE
THROUGH THIS EVENING. ON AND OFF LIGHT RAINFALL WILL CONTINUE
AROUND CENTRAL TEXAS THROUGH THE MID-AFTERNOON HOURS...WITH
TEMPERATURES HOVERING AROUND OR JUST ABOVE FREEZING FOR WACO.
A SUFFICIENT AMOUNT OF LOW-LEVEL DRY AIR SEEMS TO HAVE ADVECTED
ACROSS NORTH TEXAS TO PREVENT ANY PRECIPITATION FROM REDEVELOPING
OVER DFW AREA AIRPORTS. A WEAK UPPER LEVEL DISTURBANCE OVER FAR
WEST TEXAS WILL MOVE NORTHEAST THROUGH THIS AFTERNOON PROVIDING
PERSISTENT LIFT OVER CENTRAL TEXAS FOR ON AND OFF LIGHT RAIN. FOR
THE WACO TAF...THE CURRENT TEMPERATURE WAS 33 DEGREES...AND THE
TEMPERATURE IS UNLIKELY TO CHANGE SIGNIFICANTLY OVER THE NEXT FEW
HOURS. AS A RESULT...HAVE SIMPLY LEFT A MENTION OF LIGHT RAIN IN
THE FORECAST WITH MVFR CIGS THROUGH THIS AFTERNOON FOR KACT.
LEFT MVFR CIGS IN PLACE WITH NO MENTION OF PRECIPITATION ACROSS
ALL OF THE DFW AREA TAF SITES THROUGH THIS EVENING. LINGERED MVFR
CIGS IN PLACE LONGER THAN THE PREVIOUS FORECAST DUE TO THE LATEST
FORECAST SOUNDINGS FROM THE HRRR WHICH SEEMS TO BE HANDLING
CURRENT CONDITIONS FAIRLY ACCURATELY. DRY AIR ADVECTION AND MID-
LEVEL SUBSIDENCE ARE EXPECTED ACROSS THE ENTIRE REGION THIS
EVENING...WHICH SHOULD ALLOW LOW CLOUDS TO SCATTER OUT JUST
LEAVING VFR CLOUDS IN PLACE.
A SECOND UPPER LEVEL DISTURBANCE WILL SPREAD LIFT OVER THE REGION
EARLY TOMORROW MORNING. THE LIFT IS FAIRLY STRONG WITH THIS
DISTURBANCE...HOWEVER THE LOW-LEVEL ATMOSPHERE IS EXPECTED TO
REMAIN QUITE DRY. AS A RESULT...THINK THAT WE WILL HAVE SNOW
GENERATED FROM CLOUDS BASED AT NEAR THE 700 MB LEVEL...OR 9000 FT
AGL. BELOW THE 700 MB LEVEL...DRY AIR IS EXPECTED TO PREVENT MOST
OF THIS SNOW FROM REACHING THE GROUND. AS A RESULT...LEFT SNOW OUT
OF THE FORECAST FOR TOMORROW MORNING FOR ALL AREA TAF SITES. WILL
CONTINUE TO WATCH LOW-LEVEL MOISTURE PROFILES CLOSELY
OVERNIGHT...HOWEVER ALL MODEL GUIDANCE INDICATES THIS DRY AIR WILL
BE IN PLACE...SO DO NOT SEE MUCH MORE THAN FLURRIES MAKING IT
THROUGH 8-9000 FEET OF DRY AIR BELOW THE SNOW GENERATING CLOUDS.
CAVANAUGH
&&
.UPDATE...
THE COLD FRONT HAS PUSHED WELL SOUTH OF THE REGION BUT A MIXTURE
OF LIGHT RAIN AND LIGHT FREEZING RAIN/DRIZZLE...OCCASIONALLY WITH
A FEW SLEET PELLETS...CONTINUES SOUTH OF A LINE FROM CISCO TO
DALLAS TO PARIS. TEMPERATURES SOUTH OF INTERSTATE 20 AND WEST OF
INTERSTATE 35 ARE WHERE THE FREEZING RAIN/DRIZZLE IS OCCURRING. A
VERY THIN GLAZE OF ICE MAY FORM ON METAL SURFACES AND POSSIBLY
TREE LEAVES...BUT ACCUMULATIONS OF ICE ON ROADWAYS ARE NOT
EXPECTED AND THUS WE DO NOT EXPECT ANY IMPACTS TO TRAVEL. THE
RAIN/DRIZZLE WILL CONTINUE THROUGH THE AFTERNOON HOURS...ENDING
FROM WEST TO EAST BY THIS EVENING. NEW MODEL DATA THIS MORNING
SUGGESTS A NEW BAND OF PRECIPITATION WILL FORM SOUTH OF INTERSTATE
20 AROUND MIDDAY DUE TO FORCING ALONG THE 850 MB FRONT AS A
SHEARED SHORTWAVE...CURRENTLY OVER WEST TEXAS...MOVES ACROSS NORTH
TEXAS. THIS NEXT WAVE OF PRECIPITATION MAY ALREADY BE TAKING SHAPE
FROM HAMILTON WEST TOWARDS OZONA. THROUGH AT LEAST THE EARLY
AFTERNOON HOURS...FREEZING RAIN/DRIZZLE WILL STILL BE POSSIBLE
WITH THIS ADDITIONAL PRECIPITATION UNTIL TEMPERATURES WARM NEAR
AND ABOVE FREEZING. HAVE KEPT HIGH POPS ACROSS THE SOUTHERN HALF
OF THE CWA FOR THIS REASON EVEN THOUGH THE COVERAGE IS NOT
EXPECTED TO BE WIDESPREAD AND ANY ADDITIONAL ACCUMULATIONS LESS
THAN 0.02 INCHES OF LIQUID/MELTED PRECIPITATION.
OTHERWISE...EXPECT CLOUD COVER TO THIN AND THEN EVENTUALLY BREAK
UP ACROSS OUR WESTERN AND NORTHWESTERN COUNTIES THIS AFTERNOON
WHILE THE REST OF THE REGION REMAINS MOSTLY CLOUDY. HAVE LOWERED
TEMPERATURES THIS AFTERNOON A FEW DEGREES IN MOST PLACES BASED ON
CURRENT TEMPS AND EXPECTED CLOUD TRENDS FOR THE REMAINDER OF THE
DAY.
82/JLD
&&
.PREV DISCUSSION... /ISSUED 353 AM CST MON FEB 16 2015/
COLD FRONT CONTINUES TO MOVE THROUGH NORTH TEXAS THIS MORNING AND
IS CURRENTLY ALONG A LINE FROM NEAR TYLER TO CORSICANA TO KILLEEN.
TEMPERATURES HAVE FALLEN INTO THE 30S BEHIND THE FRONT WITH GUSTY
NORTHWEST WINDS. THE FREEZING LINE IS LOCATED FROM GAINESVILLE TO
MINERAL WELLS TO COMANCHE AND WILL SLOWLY ADVANCE EASTWARD THROUGH
THE EARLY MORNING HOURS. IT SHOULD BE LOCATED ACROSS THE NORTHWEST
PARTS OF THE METROPLEX BY SUNRISE. A LARGE AREA OF PRECIPITATION
IS ONGOING ALONG THE FRONTAL BOUNDARY ITSELF AND THIS IS PRIMARILY
RAIN. THE ONLY EXCEPTION HAS BEEN SOME SLEET OR SMALL HAIL WITH
THE STRONGER CONVECTIVE ELEMENTS BEHIND THE FRONT.
THE LEAD SHORTWAVE IN THE TROUGH OVER THE ROCKIES IS IN THE
PROCESS OF EJECTING EASTWARD ACROSS THE PLAINS THIS MORNING. THIS
WILL ALLOW THE COLD FRONT TO CONTINUE RACING SOUTHWARD
TODAY...TAKING THE PRECIPITATION WITH IT. MOST OF THE
PRECIPITATION WILL BE OUT OF THE AREA BY THE AFTERNOON HOURS. OUR
MAIN CONCERN IN THE IMMEDIATE SHORT TERM IS THE POTENTIAL FOR SOME
FREEZING DRIZZLE ACROSS THE NORTHWEST COUNTIES. LATEST HIGH
RESOLUTION GUIDANCE INDICATES AN AREA OF ISENTROPIC ASCENT IN THE
700-500MB LAYER THROUGH EARLY MORNING. THIS IS ASSOCIATED WITH THE
SHORTWAVE TROUGH MOVING THROUGH THE SOUTHERN PLAINS AND THE LIFT
ITSELF WILL LIKELY ONLY PERSIST FOR A FEW HOURS. RUC SOUNDINGS
ACROSS THE WESTERN COUNTIES SHOW SATURATED CONDITIONS DURING THIS
TIME ALTHOUGH DRYING WILL BEGIN TO OCCUR QUICKLY AFTER 12Z. WITH
WEAK ASCENT THROUGH A SATURATED LAYER...AREAS OF DRIZZLE ARE
LIKELY TO OCCUR. TEMPERATURES ARE ALREADY A FEW DEGREES COOLER
THAN PREVIOUSLY ANTICIPATED AND ARE LIKELY TO REMAIN 28 TO 30
DEGREES THROUGH 14Z ACROSS THE NORTHWEST PART OF THE CWA. THIS
SHOULD BE SUFFICIENT FOR SOME LIGHT ICING TO OCCUR MAINLY ON
BRIDGES OVER THE NEXT SEVERAL HOURS. WE HAVE ALREADY RECEIVED ONE
REPORT OF MINOR ICING ON BRIDGES IN MONTAGUE COUNTY. WE WENT AHEAD
AND ISSUED A FREEZING RAIN ADVISORY THROUGH MID MORNING MAINLY FOR
THESE MINOR ICE ACCUMULATIONS ON BRIDGES. MAIN ROADS SHOULD
CONTINUE TO BE FINE AS GROUND TEMPERATURES HAVE BEEN VERY WARM AND
ARE LIKELY TO MELT ANY LIGHT PRECIPITATION.
WITH PRECIPITATION COMING TO AN END LATER TODAY...THERE WILL BE
SOME CLEARING TO THE WEST. IT WILL BE A COLD DAY WITH HIGHS IN THE
30S AND 40S AREAWIDE AND GUSTY NORTHWEST WINDS KEEPING WIND CHILLS
IN THE 20S THROUGHOUT THE DAY. THE MAIN TROUGH OVER THE ROCKIES
WILL ACTUALLY CROSS THE AREA LATE TONIGHT INTO TUESDAY MORNING.
SKIES ARE EXPECTED TO BECOME CLOUDY AGAIN TONIGHT AND FORCING FROM
THIS TROUGH WILL ACTUALLY BE STRONGER...HOWEVER SIGNIFICANT DRYING
WILL HAVE ALREADY OCCURRED BELOW 700MB. IT WILL BE TOUGH TO GET ANY
ADDITIONAL PRECIPITATION LATE TONIGHT INTO EARLY TUESDAY BUT GIVEN
THE STRONG ASCENT WE WILL KEEP SOME 20 POPS FOR LIGHT SNOW MAINLY
ACROSS THE WESTERN COUNTIES. FLURRIES WILL BE POSSIBLE FARTHER TO
THE EAST INTO EARLY TUESDAY MORNING. NO SNOW ACCUMULATIONS ARE
EXPECTED.
TEMPERATURES ARE EXPECTED TO WARM THROUGH THE END OF THE WEEK WITH
HIGHS AGAIN NEAR 70 BY FRIDAY. ANOTHER STRONG SHORTWAVE WILL MOVE
INTO THE WESTERN U.S. BY THIS TIME AND LOW LEVEL MOISTURE WILL
BEGIN TO BE PULLED NORTHWARD IN RESPONSE. ANOTHER STRONG COLD
FRONT IS EXPECTED TO MOVE THROUGH NEXT WEEKEND...MOST LIKELY ON
SATURDAY WITH SCATTERED SHOWERS POSSIBLE LATE FRIDAY INTO EARLY
SUNDAY.
DUNN
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 30 48 34 55 34 / 10 10 5 0 0
WACO, TX 30 48 32 60 35 / 10 10 5 0 0
PARIS, TX 26 46 29 48 27 / 10 10 5 0 0
DENTON, TX 29 48 30 54 30 / 10 10 5 0 0
MCKINNEY, TX 28 48 30 52 30 / 10 10 5 0 0
DALLAS, TX 31 48 35 55 34 / 10 10 5 0 0
TERRELL, TX 29 47 31 54 31 / 10 10 5 0 0
CORSICANA, TX 29 47 33 58 33 / 10 10 5 0 0
TEMPLE, TX 31 48 32 61 35 / 10 10 5 0 0
MINERAL WELLS, TX 29 49 31 58 33 / 20 20 5 0 0
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
/
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1116 AM CST MON FEB 16 2015
.UPDATE...
THE COLD FRONT HAS PUSHED WELL SOUTH OF THE REGION BUT A MIXTURE
OF LIGHT RAIN AND LIGHT FREEZING RAIN/DRIZZLE...OCCASIONALLY WITH
A FEW SLEET PELLETS...CONTINUES SOUTH OF A LINE FROM CISCO TO
DALLAS TO PARIS. TEMPERATURES SOUTH OF INTERSTATE 20 AND WEST OF
INTERSTATE 35 ARE WHERE THE FREEZING RAIN/DRIZZLE IS OCCURRING. A
VERY THIN GLAZE OF ICE MAY FORM ON METAL SURFACES AND POSSIBLY
TREE LEAVES...BUT ACCUMULATIONS OF ICE ON ROADWAYS ARE NOT
EXPECTED AND THUS WE DO NOT EXPECT ANY IMPACTS TO TRAVEL. THE
RAIN/DRIZZLE WILL CONTINUE THROUGH THE AFTERNOON HOURS...ENDING
FROM WEST TO EAST BY THIS EVENING. NEW MODEL DATA THIS MORNING
SUGGESTS A NEW BAND OF PRECIPITATION WILL FORM SOUTH OF INTERSTATE
20 AROUND MIDDAY DUE TO FORCING ALONG THE 850 MB FRONT AS A
SHEARED SHORTWAVE...CURRENTLY OVER WEST TEXAS...MOVES ACROSS NORTH
TEXAS. THIS NEXT WAVE OF PRECIPITATION MAY ALREADY BE TAKING SHAPE
FROM HAMILTON WEST TOWARDS OZONA. THROUGH AT LEAST THE EARLY
AFTERNOON HOURS...FREEZING RAIN/DRIZZLE WILL STILL BE POSSIBLE
WITH THIS ADDITIONAL PRECIPITATION UNTIL TEMPERATURES WARM NEAR
AND ABOVE FREEZING. HAVE KEPT HIGH POPS ACROSS THE SOUTHERN HALF
OF THE CWA FOR THIS REASON EVEN THOUGH THE COVERAGE IS NOT
EXPECTED TO BE WIDESPREAD AND ANY ADDITIONAL ACCUMULATIONS LESS
THAN 0.02 INCHES OF LIQUID/MELTED PRECIPITATION.
OTHERWISE...EXPECT CLOUD COVER TO THIN AND THEN EVENTUALLY BREAK
UP ACROSS OUR WESTERN AND NORTHWESTERN COUNTIES THIS AFTERNOON
WHILE THE REST OF THE REGION REMAINS MOSTLY CLOUDY. HAVE LOWERED
TEMPERATURES THIS AFTERNOON A FEW DEGREES IN MOST PLACES BASED ON
CURRENT TEMPS AND EXPECTED CLOUD TRENDS FOR THE REMAINDER OF THE
DAY.
82/JLD
&&
.AVIATION...
/ISSUED 932 AM CST MON FEB 16 2015/
THE DFW AREA TAFS REMAIN UNCHANGED FROM THEIR 12Z ISSUANCE.
UPDATED THE WACO (KACT) TAF TO INCLUDE A TEMPO GROUP FOR FREEZING
RAIN FROM 16 TO 17Z. THE 1530Z TEMPERATURE AT WACO WAS 34 DEGREES
WITH ONGOING LIGHT RAIN OVER MUCH OF MCLENNAN COUNTY. TEMPERATURES
ARE EXPECTED TO FALL TO 30 TO 32 DEGREES BEFORE DRIER AIR MOVES IN
AND PRECIPITATION DISSIPATES LATER THIS MORNING.
CAVANAUGH
.../PREVIOUS AVIATION DISCUSSION/...
BAND OF LIGHT TO MODERATE RAIN HAS PUSHED EAST OF TAF SITES AND
EXPECT JUST SOME LIGHT DRIZZLE TO BE THE PRIMARY PRECIPITATE THIS
MORNING. WHILE TEMPERATURES AT AFW/FTW/DFW ARE NOW 33...ANY
DRIZZLE THAT DOES FALL WOULD HAVE THE POTENTIAL TO FREEZE ON
CONTACT TO AIRPLANE SURFACES. THAT IS BECAUSE DRIZZLE DROPLETS
WOULD LIKELY BE SUPER-COOLED...SO EVEN IF AIR TEMPERATURE STAYS
AT 33...LIGHT ICING MAY BE AN ISSUE THIS MORNING THAT REQUIRES
SOME DEICING OPERATIONS. SINCE TEMPERATURES ARE EXPECTED TO REMAIN
VERY NEAR FREEZING...AND DRIZZLE WILL BE VERY LIGHT...WE DO NOT
EXPECT THE IMPACTS WITH FREEZING DRIZZLE TO BE ON THE ORDER OF
WHAT OCCURRED AT DFW A WEEK AND A HALF AGO. THE THREAT FOR DRIZZLE
AND/OR FREEZING DRIZZLE IS EXPECTED TO END AT THE LATEST BY
16Z/10AM AT METROPLEX TAF SITES WITH BAND OF PRECIP SHIFTING
SOUTHEAST. WACO WILL LIKELY CONTEND WITH LIGHT RAIN IN THE AREA
THROUGH EARLY AFTERNOON BUT TEMPS WILL BE TOO WARM THERE FOR ANY
IMPACTS.
OTHERWISE MVFR CIGS WILL PREVAIL THIS MORNING AND INTO EARLY
AFTERNOON AT METROPLEX TAF SITES. AT WACO IFR IS EXPECTED FOR A
FEW MORE HOURS...BEFORE THEY LIFT TO MVFR AS THE FRONTAL LAYER
DEEPENS. CIGS SHOULD LIFT FURTHER TO VFR BY MID-LATE AFTERNOON.
EXPECT OVERCAST SKIES TONIGHT NEAR FL100...WITH VIRGA LIKELY FROM
SNOW FALLING ALOFT. THE LOW LEVELS LOOK TOO DRY FOR SNOW TO REACH
THE SURFACE AT TAF SITES...ALTHOUGH A STRAY SNOWFLAKE WOULD BE
POSSIBLE. WILL NOT MENTION THIS POSSIBILITY IN TAFS. VFR WILL
PREVAIL OVERNIGHT AND TOMORROW MORNING WITH LIGHT N/NW WINDS.
TR.92
&&
.PREV DISCUSSION... /ISSUED 353 AM CST MON FEB 16 2015/
COLD FRONT CONTINUES TO MOVE THROUGH NORTH TEXAS THIS MORNING AND
IS CURRENTLY ALONG A LINE FROM NEAR TYLER TO CORSICANA TO KILLEEN.
TEMPERATURES HAVE FALLEN INTO THE 30S BEHIND THE FRONT WITH GUSTY
NORTHWEST WINDS. THE FREEZING LINE IS LOCATED FROM GAINESVILLE TO
MINERAL WELLS TO COMANCHE AND WILL SLOWLY ADVANCE EASTWARD THROUGH
THE EARLY MORNING HOURS. IT SHOULD BE LOCATED ACROSS THE NORTHWEST
PARTS OF THE METROPLEX BY SUNRISE. A LARGE AREA OF PRECIPITATION
IS ONGOING ALONG THE FRONTAL BOUNDARY ITSELF AND THIS IS PRIMARILY
RAIN. THE ONLY EXCEPTION HAS BEEN SOME SLEET OR SMALL HAIL WITH
THE STRONGER CONVECTIVE ELEMENTS BEHIND THE FRONT.
THE LEAD SHORTWAVE IN THE TROUGH OVER THE ROCKIES IS IN THE
PROCESS OF EJECTING EASTWARD ACROSS THE PLAINS THIS MORNING. THIS
WILL ALLOW THE COLD FRONT TO CONTINUE RACING SOUTHWARD
TODAY...TAKING THE PRECIPITATION WITH IT. MOST OF THE
PRECIPITATION WILL BE OUT OF THE AREA BY THE AFTERNOON HOURS. OUR
MAIN CONCERN IN THE IMMEDIATE SHORT TERM IS THE POTENTIAL FOR SOME
FREEZING DRIZZLE ACROSS THE NORTHWEST COUNTIES. LATEST HIGH
RESOLUTION GUIDANCE INDICATES AN AREA OF ISENTROPIC ASCENT IN THE
700-500MB LAYER THROUGH EARLY MORNING. THIS IS ASSOCIATED WITH THE
SHORTWAVE TROUGH MOVING THROUGH THE SOUTHERN PLAINS AND THE LIFT
ITSELF WILL LIKELY ONLY PERSIST FOR A FEW HOURS. RUC SOUNDINGS
ACROSS THE WESTERN COUNTIES SHOW SATURATED CONDITIONS DURING THIS
TIME ALTHOUGH DRYING WILL BEGIN TO OCCUR QUICKLY AFTER 12Z. WITH
WEAK ASCENT THROUGH A SATURATED LAYER...AREAS OF DRIZZLE ARE
LIKELY TO OCCUR. TEMPERATURES ARE ALREADY A FEW DEGREES COOLER
THAN PREVIOUSLY ANTICIPATED AND ARE LIKELY TO REMAIN 28 TO 30
DEGREES THROUGH 14Z ACROSS THE NORTHWEST PART OF THE CWA. THIS
SHOULD BE SUFFICIENT FOR SOME LIGHT ICING TO OCCUR MAINLY ON
BRIDGES OVER THE NEXT SEVERAL HOURS. WE HAVE ALREADY RECEIVED ONE
REPORT OF MINOR ICING ON BRIDGES IN MONTAGUE COUNTY. WE WENT AHEAD
AND ISSUED A FREEZING RAIN ADVISORY THROUGH MID MORNING MAINLY FOR
THESE MINOR ICE ACCUMULATIONS ON BRIDGES. MAIN ROADS SHOULD
CONTINUE TO BE FINE AS GROUND TEMPERATURES HAVE BEEN VERY WARM AND
ARE LIKELY TO MELT ANY LIGHT PRECIPITATION.
WITH PRECIPITATION COMING TO AN END LATER TODAY...THERE WILL BE
SOME CLEARING TO THE WEST. IT WILL BE A COLD DAY WITH HIGHS IN THE
30S AND 40S AREAWIDE AND GUSTY NORTHWEST WINDS KEEPING WIND CHILLS
IN THE 20S THROUGHOUT THE DAY. THE MAIN TROUGH OVER THE ROCKIES
WILL ACTUALLY CROSS THE AREA LATE TONIGHT INTO TUESDAY MORNING.
SKIES ARE EXPECTED TO BECOME CLOUDY AGAIN TONIGHT AND FORCING FROM
THIS TROUGH WILL ACTUALLY BE STRONGER...HOWEVER SIGNIFICANT DRYING
WILL HAVE ALREADY OCCURRED BELOW 700MB. IT WILL BE TOUGH TO GET ANY
ADDITIONAL PRECIPITATION LATE TONIGHT INTO EARLY TUESDAY BUT GIVEN
THE STRONG ASCENT WE WILL KEEP SOME 20 POPS FOR LIGHT SNOW MAINLY
ACROSS THE WESTERN COUNTIES. FLURRIES WILL BE POSSIBLE FARTHER TO
THE EAST INTO EARLY TUESDAY MORNING. NO SNOW ACCUMULATIONS ARE
EXPECTED.
TEMPERATURES ARE EXPECTED TO WARM THROUGH THE END OF THE WEEK WITH
HIGHS AGAIN NEAR 70 BY FRIDAY. ANOTHER STRONG SHORTWAVE WILL MOVE
INTO THE WESTERN U.S. BY THIS TIME AND LOW LEVEL MOISTURE WILL
BEGIN TO BE PULLED NORTHWARD IN RESPONSE. ANOTHER STRONG COLD
FRONT IS EXPECTED TO MOVE THROUGH NEXT WEEKEND...MOST LIKELY ON
SATURDAY WITH SCATTERED SHOWERS POSSIBLE LATE FRIDAY INTO EARLY
SUNDAY.
DUNN
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 37 30 48 34 55 / 20 10 10 5 0
WACO, TX 35 30 48 32 60 / 80 10 10 5 0
PARIS, TX 37 26 46 29 48 / 20 10 10 5 0
DENTON, TX 36 29 48 30 54 / 10 10 10 5 0
MCKINNEY, TX 35 28 48 30 52 / 10 10 10 5 0
DALLAS, TX 38 31 48 35 55 / 20 10 10 5 0
TERRELL, TX 37 29 47 31 54 / 30 10 10 5 0
CORSICANA, TX 38 29 47 33 58 / 70 10 10 5 0
TEMPLE, TX 36 31 48 32 61 / 80 10 10 5 0
MINERAL WELLS, TX 36 29 49 31 58 / 10 20 20 5 0
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
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