Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 12/28/15
AREA FORECAST DISCUSSION
NWS TUCSON AZ
910 AM MST SAT DEC 26 2015
.SYNOPSIS...A COLD STORM SYSTEM WILL BRING SCATTERED SNOW SHOWERS
MAINLY NEAR THE NEW MEXICO BORDER INTO SUNDAY. EXPECT WIDESPREAD
FREEZING TEMPERATURES TONIGHT...WITH A HARD FREEZE WARNING FOR
PORTIONS OF PIMA COUNTY AND SOUTHERN PINAL COUNTY. SCATTERED VALLEY
RAIN AND MOUNTAIN SNOW SHOWERS WILL OCCUR MONDAY NIGHT INTO TUESDAY
AS ANOTHER SYSTEM MOVES ACROSS THE AREA. DRY CONDITIONS WITH A
WARMING TREND WILL THEN PREVAIL WEDNESDAY THROUGH FRIDAY.
&&
.DISCUSSION...IR/VISIBLE SATELLITE IMAGERY AND SURFACE OBSERVATIONS
DEPICTED PARTLY CLOUDY TO CLOUDY SKIES FROM THE TUCSON METRO AREA
EASTWARD TO THE NEW MEXICO BORDER AT THIS TIME. CLEAR SKIES WERE
ONGOING ACROSS WRN/CENTRAL PIMA COUNTY AND SOUTH CENTRAL PINAL
COUNTY WEST-TO-NORTHWEST OF TUCSON. 26/12Z KTWC SOUNDING TOTAL
PRECIP WATER VALUE WAS ONLY 0.18 INCH...INDICATIVE OF A VERY DRY
ENVIRONMENT. HOWEVER...A NEARLY SATURATED LAYER WAS OBSERVED AROUND
700 MB. 26/12Z UPPER AIR PLOTS DEPICTED A DEEP TROUGH THAT EXTENDED
FROM THE NRN ROCKIES SOUTHWESTWARD INTO THE SWRN CONUS...AND A
541 DM LOW WAS ANALYZED OVER EAST CENTRAL ARIZONA NEAR SHOW LOW/
KSOW. MODERATE TO STRONG WLY/SWLY FLOW PREVAILED ABOVE 600 MB.
THE UPPER LOW WILL MOVE SEWD TO NEAR THE FAR SE ARIZONA/SW NEW
MEXICO BORDER LATE THIS AFTERNOON. THE UPPER LOW WILL THEN MOVE EWD
INTO WEST TEXAS BY MIDDAY SUN. 26/12Z NAM/GFS AND 2-3 HRRR SOLUTIONS
WERE VERY SIMILAR WITH DEPICTING MEASURABLE PRECIP TO OCCUR MAINLY
NEAR THE NEW MEXICO BORDER THRU SUN MORNING. THE BULK OF THIS PRECIP
SHOULD OCCUR IN THE FORM OF SNOW SHOWERS. HOWEVER...SNOW ACCUMS
WILL BE FAIRLY LIGHT...WITH A FEW VALLEY LOCALES PERHAPS POISED TO
RECEIVE AROUND ONE INCH...AND 3-6 INCHES OF SNOW MAY ACCUMULATE ABOVE
6500 FEET IN THE MOUNTAINS.
GUSTY NORTHWEST WINDS WILL ACCOMPANY THIS LOW PRESSURE SYSTEM THIS
AFTERNOON AND EVENING...ESPECIALLY FROM TUCSON EWD TO THE NEW MEXICO
BORDER. THE UPPER GILA RIVER VALLEY...INCLUDING SAFFORD...APPEARS TO
THE FAVORED AREA FOR THE STRONGEST WIND SPEEDS. BELIEVE THAT
WIDESPREAD AND LONG-LIVED WIND ADVISORY CRITERIA WILL NOT BE
MET...GIVEN THE PROGRESSIVELY DECREASED WIND SPEEDS PER 3-4 RECENT
MODEL SOLUTIONS.
HIGH TEMPS THIS AFTERNOON ARE FORECAST TO AVERAGE NEARLY 10-20 DEGS
BELOW NORMAL. LOW TEMPS TONIGHT WILL ALSO BE WELL BELOW NORMAL. A
HARD FREEZE WARNING IS IN EFFECT FROM MIDNIGHT TONIGHT TO 8 AM MST
SUNDAY FOR THE TUCSON METRO AREA...MUCH OF THE TOHONO O`ODHAM
NATION...AND SOUTH CENTRAL/SE PINAL COUNTY. PLEASE REFER TO AWIPS
PRODUCT PHXNPWTWC /WMO HEADER WWUS75 KTWC/ FOR ADDITIONAL
INFORMATION.
DRY CONDITIONS WILL PREVAIL SUN NIGHT AND MON AS A SHORTWAVE RIDGE
FLATTENS AND MOVES EAST OF THE AREA. THE NEXT UPPER LOW IS THEN
PROGGED TO MOVE EWD ACROSS NRN ARIZONA INTO NRN NEW MEXICO LATE MON
NIGHT INTO TUE. THIS SYSTEM WILL BRING ISOLATED TO SCATTERED VALLEY
RAIN/MOUNTAIN SNOW SHOWERS TO THE AREA. THE INHERITED OFFICIAL
FORECAST DEPICTS SNOW LEVELS OF 5000-6500 LATE MON EVENING TO FALL TO
AROUND 4000-5000 FEET MIDDAY TUE. RAINFALL/SNOWFALL AMOUNTS SHOULD BE
FAIRLY LIGHT GIVEN THE RAPID MOVEMENT OF THIS SYSTEM. DRY CONDITIONS
WITH A MODEST WARMING TREND WILL THEN PREVAIL WED-FRI IN RESPONSE TO
A STRONG HIGH PRESSURE RIDGE ADJACENT THE WEST COAST.
&&
.AVIATION...VALID THRU 27/18Z.
SCATTERED -SHSN WILL OCCUR MAINLY NEAR THE NEW MEXICO BORDER INTO
SUNDAY MORNING. EXPECT OCCASIONAL MVFR CONDITIONS AND PERHAPS IFR
CONDITIONS DUE TO RESTRICTED CEILINGS AND VISIBILITIES. OTHERWISE...
CLEAR SKIES WILL PREVAIL WEST OF KTUS THRU THE PERIOD. KTUS VICINITY
EASTWARD...CLOUD BASES WILL MOSTLY RANGE FROM 8K-12K FT MSL. SURFACE
WIND THIS AFTERNOON AND EVENING WILL BE NWLY 12-25 KTS WITH GUSTS TO
AROUND 35 KTS. THE STRONGEST SPEEDS WILL BE NE OF KTUS NEAR KSAD.
THEREAFTER...SURFACE WIND WILL DIMINISH TO GENERALLY LESS THAN 10
KTS AND CONTINUE INTO SUNDAY MORNING. AVIATION DISCUSSION NOT
UPDATED FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...THERE IS A CHANCE OF SNOW SHOWERS MAINLY NEAR THE
NEW MEXICO BORDER INTO SUNDAY. SCATTERED VALLEY RAIN AND MOUNTAIN
SNOW SHOWERS WILL OCCUR MONDAY NIGHT INTO TUESDAY. OTHERWISE...
DRY CONDITIONS WILL PREVAIL DURING THE UPCOMING WORK WEEK.
EXPECT GUSTY NORTHWEST WINDS THIS AFTERNOON...AND ESPECIALLY IN THE
UPPER GILA VALLEY INCLUDING SAFFORD...WITH GUSTS OF 30-40 MPH
POSSIBLE. GENERALLY LIGHT TERRAIN DRIVEN WINDS WILL THEN PREVAIL
DURING MUCH OF THE UPCOMING WEEK. THE EXCEPTION IS NEXT FRIDAY WHEN
GUSTY EAST WINDS MAY DEVELOP.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...
HARD FREEZE WARNING FROM MIDNIGHT TONIGHT TO 8 AM MST SUNDAY
FOR AZZ502-504>506.
&&
$$
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FRANCIS
AREA FORECAST DISCUSSION
NWS TUCSON AZ
258 AM MST SAT DEC 26 2015
.SYNOPSIS...A COLD STORM SYSTEM WILL IMPACT PARTS OF SOUTHEAST
ARIZONA THROUGH THE WEEKEND...WITH MOST OF THE PRECIPITATION
OCCURRING EAST OF TUCSON AND IN THE MOUNTAINS. WIND WILL BE GUSTY
WINDS AT TIMES AND MUCH COLDER TEMPERATURES ARE EXPECTED THIS
WEEKEND. ANOTHER SYSTEM COULD BRING A CHANCE OF VALLEY RAIN AND
MOUNTAIN SNOW MONDAY NIGHT INTO TUESDAY.
&&
.DISCUSSION...AN UPPER LOW CONTINUED TO EVOLVE OVER THE STATE EARLY
THIS MORNING...WITH A NICE TAP OF MOISTURE BEING PULLED NORTHWARD
THROUGH SOUTHEAST ARIZONA INTO THE CENTRAL PLAINS. RECENT SATELLITE
AND RADAR IMAGERY WERE SHOWING A BAND OF LOW CLOUDS EXTENDING FROM
THE WHITE MOUNTAINS SOUTHWEST TO TUCSON AND NOGALES. SPRINKLES AND
SNOW FLURRIES HAVE BEEN REPORTED NEAR TUCSON AND IN THE SIERRA VISTA
AREA. LATEST HRRR SOLUTIONS SHIFT THIS BAND OF CLOUDS AND LIGHT
PRECIPITATION EASTWARD...EXITING THE AREA THIS AFTERNOON. WILL
LIKELY SEE SOME WRAP AROUND CLOUDINESS AND SHOWERS THIS AFTERNOON
AND EVENING EAST OF TUCSON AS THE UPPER LOW TRACKS SOUTHEAST OF THE
AREA. STORM TOTAL SNOW ACCUMULATIONS WILL RANGE FROM LIGHT AMOUNTS
WITH ISOLATED SPOTS UP TO 1 INCH IN THE VALLEYS OF COCHISE AND
GRAHAM COUNTIES TO 3 TO 6 INCHES ABOVE 6500 FEET IN THE EASTERN
MOUNTAINS. THE LOW PRESSURE SYSTEM WILL ALSO USHER IN A MUCH COLDER
AIR MASS TODAY WITH HIGHS ABOUT 10 TO 15 DEGREES BELOW NORMAL.
CLEARING SKIES TONIGHT IN COMBINATION WITH THE COLDER AIR MASS WILL
RESULT IN A WIDESPREAD HARD FREEZE IN THE LOWER DESERTS
TONIGHT/SUNDAY MORNING. A HARD FREEZE WARNING HAS BEEN POSTED FOR
PARTS OF PINAL AND PIMA COUNTIES FROM MIDNIGHT TONIGHT UNTIL 8 AM
MST SUNDAY. ALONG WITH THE PRECIPITATION AND COLDER TEMPERATURES...
STRONG AND GUSTY WINDS CAN BE ANTICIPATED TODAY ESPECIALLY IN THE
UPPER GILA RIVER VALLEY AROUND SAFFORD. A SECONDARY SYSTEM WILL
BRING ANOTHER CHANCE OF SHOWERS AND COOLER TEMPERATURES LATE MONDAY
INTO TUESDAY.
&&
.AVIATION...VALID THRU 27/12Z.
EXPECT ISOLATED TO SCATTERED -SHRASN EAST OF KTUS THRU THE FORECAST
PERIOD. MOUNTAIN TOPS WILL BE OBSCURED AT TIMES IN CLOUDS/PRECIP AND
MVFR CIGS/VSBYS ARE POSSIBLE IN VALLEYS NEAR NM STATE LINE AFT
26/18Z. DRY CONDITIONS WILL PREVAIL FROM KTUS VICINITY WEST AND
NORTHWEST TOWARD KPHX. OTHERWISE VALLEY CLOUD BASES WILL MAINLY
RANGE FROM 4K-8K FT AGL. SFC WIND WLY/NWLY AT 10-15 KTS TIL 26/18Z.
AFT 26/18Z...NWLY SFC WIND INCREASING TO 15-25 KTS IN FAVORED VALLEY
LOCATIONS...WITH GUSTS TO 30-35 KTS...STRONGER IN THE VCNTY OF KSAD.
AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...THERE WILL BE A CHANCE OF VALLEY RAIN AND MOUNTAIN
SNOW SHOWERS EAST OF TUCSON THROUGH TONIGHT. DRY CONDITIONS WILL
PREVAIL FROM TUCSON WESTWARD INTO WESTERN PIMA COUNTY AND SOUTHERN
PINAL COUNTY. A SLIGHT CHANCE OF VALLEY RAIN AND MOUNTAIN SNOW
SHOWERS CONTINUES MAINLY NEAR THE NEW MEXICO BORDER ON SUNDAY...THEN
DRY CONDITIONS ARE EXPECTED AREA-WIDE SUNDAY NIGHT INTO MONDAY. A
FAST MOVING SYSTEM WILL BRING ISOLATED TO SCATTERED VALLEY RAIN AND
MOUNTAIN SNOW SHOWERS FROM TUCSON EASTWARD MONDAY NIGHT AND TUESDAY.
DRY CONDITIONS WILL THEN PREVAIL NEXT WEDNESDAY THROUGH FRIDAY.
EXPECT GUSTY NORTHWEST WINDS TODAY...WITH THE STRONGEST WINDS DURING
THE AFTERNOON HOURS...AND ESPECIALLY IN THE UPPER GILA VALLEY
INCLUDING SAFFORD...WITH GUSTS OF 30-40 MPH POSSIBLE. GENERALLY
LIGHT TERRAIN DRIVEN WINDS WILL THEN PREVAIL DURING MUCH OF THE
UPCOMING WEEK. THE EXCEPTION IS NEXT FRIDAY WHEN GUSTY EAST WINDS
MAY DEVELOP.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...HARD FREEZE WARNING SUNDAY
MORNING FOR AZZ502-504>506.
&&
$$
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AREA FORECAST DISCUSSION
NWS NEW YORK NY
1040 PM EST SUN DEC 27 2015
.SYNOPSIS...
A COLD FRONT WILL MOVE ACROSS BEFORE MIDNIGHT. HIGH PRESSURE WILL
BRIEFLY BUILD IN LATE TONIGHT...AND THEN SLOWLY RETREAT TO THE
NORTHEAST INTO TUESDAY. MEANWHILE...A WARM FRONT WILL APPROACH
FROM THE SOUTH MONDAY NIGHT...WITH AN AREA OF LOW PRESSURE
RIDING ALONG IT AND PASSING JUST TO THE SOUTH ON TUESDAY.
WEAK HIGH PRESSURE WILL BUILD IN TUESDAY NIGHT AND WEDNESDAY.
A FRONTAL SYSTEM WILL APPROACH WEDNESDAY NIGHT INTO THURSDAY.
WEAK HIGH PRESSURE WILL RETURN TO END THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
MAIN CHANGE IS PER LATEST HRRR AND RADAR TRENDS BRING ALL SHOWERS
TO A CLOSE BY MIDNIGHT.
SHOULD GET FAIRLY RAPID DROP-OFF IN TEMPERATURES AS STRONG
CANADIAN HIGH PRESSURE BUILDS IN. TEMPERATURES WILL DROP TO NEAR
40 INVOF NYC...AND INTO THE 30S ELSEWHERE.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/...
A DEEP LAYERED RIDGE BUILDS OVER THE AREA MONDAY...WITH ASSOCIATED
SUBSIDENCE KEEPING THINGS DRY. HOWEVER...SHOULD HAVE SUFFICIENT MID
TO UPPER LEVEL MOISTURE FOR MID AND HIGH CLOUDS. HIGHS MONDAY
SHOULD BE CLOSE TO AVG.
THE DEEP LAYERED RIDGE AXIS SLIDES TO THE NE MONDAY NIGHT...ALLOWING
FOR OVER RUNNING FLOW TO SET UP OVER THE REGION...WHICH CONTINUES
THROUGH MOST OF TUESDAY WITH THE SURFACE LOW FORECAST TO PASS JUST
TO THE S OF LONG ISLAND. WITH A RETREATING DAMMING HIGH HELPING TO
KEEP LOW LEVEL COLD AIR IN PLACE...ESPECIALLY OVER THE
INTERIOR...SHOULD SEE A WINTRY MIX MONDAY NIGHT. IN ADDITION A
NORTHERN STREAM TROUGH PASSES TO THE N ON TUESDAY.
NYC PROPER AND LONG ISLAND SHOULD EXPERIENCE A PERIOD OF SLEET
BEFORE CHANGING TO ALL RAIN DURING THE NIGHT...WITH LITTLE OR NO
SLEET ACCUMULATION EXPECTED. MOST OF NE NJ/S WESTCHESTER/COASTAL CT
ZONES SHOULD EXPERIENCE A LONGER PERIOD OF SLEET AND MAYBE A BRIEF
BOUT OF FREEZING RAIN BEFORE CHANGING TO ALL RAIN BY AROUND SUNRISE.
FARTHER N OVER THE CWA...EXPECT MORE PROLONGED SLEET/LIGHT FREEZING
RAIN...POSSIBLY EVEN WITH SOME SNOW TO START ACROSS INTERIOR SE CT.
THE PRECIPITATION THERE SHOULD CHANGE TO ALL RAIN BY MIDDAY TUESDAY.
BASED ON THE ABOVE...HAVE ISSUED A WINTER WEATHER ADVISORY FOR
INTERIOR S CT...ALL OF THE LOWER HUDSON VALLEY EXCEPT S WEST CHESTER
AND W PASSAIC COUNTY FROM 1Z-16Z TUESDAY. ALSO BASED ON THE ABOVE
EXPECT LITTLE OR NO IMPACT OVER NYC PROPER AND LONG ISLAND -
THOUGH CANNOT COMPLETELY RULE OUT A BRIEF PERIOD OF FREEZING RAIN.
IT IS MORE UNCERTAIN OVER THAT MIDDLE AREA DESCRIBED ABOVE AS TO
WHETHER OR NOT THERE WILL BE ANY WIDESPREAD ACCRETION OF ICE OR
NOT...SO COULD SEE REFINEMENT TO THE ADVISORY AREA WITH LATTER
SHIFTS. THE MAIN CAUSE FOR CONCERN HERE IS ALL MODELS HISTORICALLY
ERODE THE DAMMING HIGH AND HENCE SCOUR OUT THE LOW LEVEL COLD AIR
TOO QUICKLY...BUT GIVEN IN A CLIMATOLOGICAL PATTERN ON A WHOLE...NOT
WILLING TO MAKE TYPICAL CLIMATOLOGICAL ADJUSTMENTS AT THIS TIME.
MAIN LIMITING FACTOR ON PRECIPITATION AMOUNT MONDAY NIGHT IS THAT
WITH CORE OF 700-500 HPA ENERGY FORECAST TO STAY OVER THE GREAT
LAKES/ST LAWRENCE RIVER VALLEY MONDAY NIGHT/TUESDAY...PRECIPITATION
INTENSITY SHOULD BE MAINLY LIGHT THEN. A 60+ KT LOW LEVEL JET
PASSES JUST S OF LONG ISLAND ON TUESDAY...SO THIS SHOULD ENHANCE
RAINFALL THEN...ESPECIALLY ACROSS S ZONES.
FOR TEMPERATURES MONDAY NIGHT AND TUESDAY USED A BLEND OF
MAV/MET/ECS GUIDANCE AND NAM 2-METER TEMPERATURES...WEIGHED MORE
TOWARDS COOLER NAM TO REFLECT IMPACT OF EVAPORATIONAL COOLING AND
GFS TYPICALLY TOO FAST TO ERODE LOW LEVEL COLD AIR. TEMPERATURES
SHOULD RUN AROUND 5-10 DEGREES ABOVE NORMAL MONDAY NIGHT AND TUESDAY.
DEEP LAYERED RIDGING BUILDS BACK IN TUESDAY NIGHT...WITH MAINLY DRY
CONDITIONS AND DECREASING CLOUDINESS EXPECTED. FOR NOW THOUGH...DUE
TO SOME UNCERTAINTY IN TIMING OF SYSTEMS...HAVE SLIGHT CHANCE TO
CHANCE POPS IN EARLY TUESDAY EVENING. LOWS TUESDAY NIGHT ARE BASED
ON A BLEND OF MAV/MET GUIDANCE AND NAM 2-METER TEMPERATURES AND
SHOULD BE AROUND 10-15 DEGREES ABOVE NORMAL.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
FAIR WEATHER RETURNS FOR MUCH OF WEDNESDAY AS WEAK HIGH PRESSURE
REMAINS OVER THE REGION. THE NEXT FRONTAL SYSTEM SHOULD BRING RAIN
LATE WEDNESDAY AFTERNOON THROUGH THURSDAY. TEMPERATURES ARE EXPECTED
TO BE WARM ENOUGH FOR THE PRECIPITATION TO REMAIN RAIN THROUGHOUT
THE EVENT. WEAK HIGH PRESSURE THEN BUILDS BACK INTO THE REGION
THURSDAY NIGHT THROUGH SUNDAY PROVIDING MOSTLY DRY CONDITIONS.
TEMPS WILL BE ABOVE AVERAGE WEDNESDAY THROUGH FRIDAY...WITH HIGHS
FROM THE MID 40S TO LOWER 50S. TEMPERATURES THEN FALL TO NEAR NORMAL
SATURDAY AND SUNDAY WITH HIGHS IN THE UPPER 30S AND LOWER 40S.
&&
.AVIATION /04Z MONDAY THROUGH FRIDAY/...
A COLD FRONT WILL MOVE ACROSS BEFORE MIDNIGHT. HIGH PRESSURE WILL
THEN BUILD IN OVERNIGHT THROUGH MONDAY AFTERNOON.
VFR CONDS...WITH A FEW LEFTOVER SHOWERS BEFORE MIDNIGHT.
WINDS NW-NNW 15-20 KT WITH GUSTS 20-30 KT SHOULD DECREASE
OVERNIGHT. GUSTS COULD DROP OFF LATE TONIGHT OUTSIDE OF THE
NYC METRO.
AS THE HIGH PASSES TO THE NORTH...WINDS WILL VEER AROUND TO THE NE
AT 10-12 KT WITH GUSTS 15-20 KT FROM AFTER DAYBREAK INTO EARLY MON
AFTERNOON. GUSTS SHOULD DROP OFF BY MID AFTERNOON.
.OUTLOOK FOR 00Z TUE THROUGH FRI...
.MON NIGHT-TUE MORNING...IFR CONDS DEVELOPING FROM SW TO NE.
E-SE WINDS G20-30KT POSSIBLE. AS FOR PRECIP TYPE...FOR NYC METRO
AND KISP...RAIN/SLEET...CHANGING TO ALL RAIN JUST BEFORE DAYBREAK.
FOR KBDR/KGON...RAIN/SLEET...CHANGING TO ALL RAIN AFTER DAYBREAK.
FOR KHPN/KSWF...SLEET/FREEZING RAIN TRANSITIONING TO RAIN BY
LATE MORNING.
.TUE AFTERNOON-EVENING...IFR OR LOWER IN RAIN. LLWS POSSIBLE.
.LATE TUE NIGHT-WED MORNING...BECOMING VFR.
.WED AFTERNOON-THU MORNING...MVFR OR LOWER DEVELOPING LATE WED IN
RAIN.
.THU AFTERNOON-FRI...VFR.
&&
.MARINE...
ISSUED SCA FOR ALL WATERS AS N-NW WINDS AFTER A COLD FRONTAL
PASSAGE GUSTS TO 25-30 KT. WINDS SHOULD DIMINISH BY DAYBREAK ON
THE SOUND/HARBOR/BAYS...BUT SCA WILL CONTINUE ON THE OCEAN THROUGH
THE DAY ON MON WITH SEAS ABOVE 5 FT.
GALE FORCE GUSTS ARE POSSIBLE OVER ALL WATERS FROM MONDAY NIGHT
INTO TUESDAY. ISSUED A GALE WATCH FOR ALL WATERS FROM MONDAY
NIGHT INTO TUESDAY MORNING.
SCA CONDITIONS ARE THEN EXPECTED FOR THE REMAINDER OF TUESDAY.
WINDS SHOULD DIMINISH TO 10 KT OR LESS OVER THE NON-OCEAN WATERS
BY TUESDAY EVENING AND SUBSIDE BELOW SCA LEVELS ON THE COASTAL
OCEAN WATERS BY THEN. HOWEVER...SEAS ON THE COASTAL OCEAN WATERS
SHOULD REMAIN AT OR ABOVE SCA LEVELS TUESDAY NIGHT.
SOME LEFT OVER 5 FT SEAS WILL LINGER INTO WEDNESDAY...HOWEVER SEAS
WILL GRADUALLY DIMINISH THROUGH THE DAY...WITH QUIET CONDITIONS
EXPECTED WEDNESDAY AFTERNOON THROUGH FRIDAY. ANOTHER CHANCE OF SMALL
CRAFT CONDITIONS WILL OCCUR OVER THE WEEKEND AS WIND GUSTS INCREASE
ON COLD AIR ADVECTION.
&&
.HYDROLOGY...
AROUND 1 INCH OF QPF IS EXPECTED MONDAY NIGHT-TUESDAY AND
POSSIBLY INTO TUESDAY EVENING. ONLY MINOR PONDING OF WATER IN
URBAN/POOR DRAINAGE AREAS IS EXPECTED AT THIS TIME AS A RESULT.
&&
.TIDES/COASTAL FLOODING...
AN APPROACHING LOW PRESSURE SYSTEM MAY RESULT IN MINOR COASTAL
FLOODING IMPACTS DURING THE TUESDAY MORNING/EARLY AFTERNOON HIGH
TIDE CYCLE. SURGE OF 2 TO 2 1/2 FT IS NEEDED TO EXCEED MINOR
FLOODING THRESHOLDS. CURRENT TIDAL GUIDANCE SUGGEST THAT WATER
LEVELS WILL REMAIN BELOW MINOR THRESHOLDS FOR MOST AREAS...WITH A
MARGINAL THREAT TO TYPICALLY VULNERABLE AREAS ALONG THE SOUTH SHORE
BAYS OF LONG ISLAND/NYC.
MINOR ATLANTIC OCEAN BEACH EROSION IS ALSO POSSIBLE FROM AN E TO W
SWEEP OF 5 TO 7 FT SURF AND THE HIGHER WATER LEVELS.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...WINTER WEATHER ADVISORY FROM 8 PM MONDAY TO 11 AM EST TUESDAY
FOR CTZ005>008.
NY...WINTER WEATHER ADVISORY FROM 8 PM MONDAY TO 11 AM EST TUESDAY
FOR NYZ067>070.
NJ...WINTER WEATHER ADVISORY FROM 8 PM MONDAY TO 11 AM EST TUESDAY
FOR NJZ002.
MARINE...GALE WATCH FROM MONDAY EVENING THROUGH TUESDAY MORNING FOR
ANZ330-335-338-340-345-350-353-355.
SMALL CRAFT ADVISORY UNTIL 6 AM EST MONDAY FOR ANZ330-335-338-
340-345.
SMALL CRAFT ADVISORY UNTIL 6 PM EST MONDAY FOR ANZ350-353-355.
&&
$$
SYNOPSIS...BC/MALOIT
NEAR TERM...BC/GOODMAN/MALOIT
SHORT TERM...MALOIT
LONG TERM...BC
AVIATION...GOODMAN
MARINE...BC/GOODMAN/MALOIT
HYDROLOGY...BC/MALOIT
TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS TAUNTON MA
1014 PM EST SUN DEC 27 2015
.SYNOPSIS...
A COLD FRONT MOVING THROUGH THE REGION WILL MARK THE ENTRANCE OF
COLDER AIR INTO THE REGION TONIGHT AND MONDAY. A WINTRY MIX FOR
LATE MONDAY NIGHT INTO TUESDAY WILL MAKE FOR A HAZARDOUS TUESDAY
MORNING COMMUTE. A BRIEF REPRIEVE OCCURS WEDNESDAY...PRIOR TO
ANOTHER STORM SYSTEM ARRIVING THURSDAY WHICH SHOULD BRING RAIN.
DRY AND SEASONABLE WEATHER FOLLOWS FOR NEW YEAR/S WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
1015 PM UPDATE...RAIN IS QUICKLY SHIFTING SOUTH AS THE COLD FRONT
PUSHES THROUGH. CLEARING IS A BIT SLOWER BEHIND THE FRONT WITH
OVERCAST SKIES STILL IN PLACE ACROSS THE REGION. MADE A FEW MINOR
UPDATES TO THE FORECAST TO ACCOUNT FOR THE LATEST TRENDS.
OTHERWISE NO MAJOR CHANGES TO THE FORECAST.
630 PM UPDATE ...
FOLLOWING HRRR TRENDS...COLD FRONT SWEEPING S BEHIND WHICH DRIER
AIR AND SUBSIDENCE SHOULD PREVAIL. SHOULD SEE A GRADUAL CLEARING
OVERNIGHT AS COLD AIR ADVECTION PROCEEDS DROPPING LOWS DOWN INTO
THE MID- TO UPPER-20S...LOW-30S TO THE S. SHOWERS / LOW CLOUDS /
FOG ALONG AND AHEAD OF THE COLD FRONT OTHERWISE. THIS ACTIVITY
SHOULD ONLY LAST THE NEXT COUPLE OF HOURS FOR FAR S NEW ENGLAND.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH 6 PM MONDAY/...
HIGH PRESSURE BUILDS ACROSS QUEBEC MON...RESULTING IN N/NE FLOW OF
COLD AIR INTO REGION. CROSS SECTIONS SHOW PLENTY OF DRY AIR DURING
MORNING WHICH GIVES WAY TO INCREASING HIGH AND EVENTUALLY MID
LEVEL MOISTURE LATER IN DAY. SO EXPECT PLENTY OF SUNSHINE TO
START BEFORE INCREASING CLOUDS IN AFTERNOON. MODEL 2M TEMPERATURES
DO NOT SUGGEST MUCH OF WARMUP WITH COLD ADVECTION AT LOWER
LEVELS...SO HIGHS SHOULD STAY IN 30S ACROSS MUCH OF SOUTHERN NEW
ENGLAND WITH PERHAPS SOME OF HIGHER TERRAIN STAYING IN UPPER 20S.
&&
.LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
*/ HIGHLIGHTS...
- POTENTIALLY DANGEROUS FIRST WINTER STORM OF THE SEASON
- ROUGHLY 1-3 INCHES OF SNOW...LOCALLY HIGHER ACROSS N-MASS -
ONE TO TWO TENTHS OF ICE POSSIBLE ESP ACROSS THE INTERIOR -
GREATEST CONCERN: ELEVATED ROADWAYS / TREES / POWER LINES -
TRAVEL IS NOT RECOMMENDED AROUND TUESDAY MORNING
*/ OVERVIEW...
REITERATING...FOCUS IS MAINLY UPON MONDAY NIGHT INTO TUESDAY.
EVALUATING DETERMINISTIC / PROBABILISTIC / ENSEMBLE / ANALOG
GUIDANCE...ALL SIGNS POINT TO YES FOR AN ADVISORY-LEVEL WINTER
WEATHER EVENT. INITIAL SNOWS ARE ANTICIPATED WITH CHANGE OVER TO
SLEET...THEN THEREAFTER IT IS APPEARING MORE LIKELY THAT ACROSS
THE INTERIOR WE WILL SEE A SIGNIFICANT ICING EVENT WITH A
PROLONGED PERIOD OF FREEZING RAIN.
OUR FIRST WINTER STORM OF THE SEASON IS NOT AN EASY ONE TO FORECAST.
NUMEROUS INTANGIBLES AND INGREDIENTS INVOLVED WHICH CAN EASILY SKEW
SNOW / SLEET / ICE ACCUMULATIONS...NAMELY GROUND TEMPERATURES / A
COASTAL FRONT SETUP BETWEEN N-WINDS OVER THE INTERIOR AND
E-ONSHORE FLOW / THERMAL PROFILES ALOFT / AND PRECIPITATION
INTENSITY.
PATIENCE AND AWARENESS IS OF THE UTMOST. THIS IS ONE MESSY FORECAST
AND HONESTLY IT IS NOT GOING TO BE PERFECT CONSIDERING THE MULTIPLE
PRECIPITATION TYPES BUT THE TAKEAWAY IS ITS SIGNIFICANCE. ONGOING
DURING THE OVERNIGHT INTO THE TUESDAY MORNING COMMUTE...ONLY A
TRACE OF SNOW / ICE ACCUMULATION LEADS TO HAVOC ALONG ROADWAYS
ESPECIALLY THOSE THAT ARE ELEVATED.
ITS NOT SO MUCH THE ACCUMULATIONS THAT ARE IMPORTANT IN THIS RESPECT
BUT RATHER THE IMPACT OF WHICH SHOULD ENCOURAGE THE PUBLIC TO STAY
OFF AREA ROADWAYS FOR THIS TIMEFRAME. ICE ACCUMULATIONS ARE FORECAST
TO BE A MAJOR THREAT IN ADDITION TO THE SNOW / SLEET. MORE DETAILED
DISCUSSION BELOW.
*/ DISCUSSION...
MONDAY NIGHT INTO TUESDAY NIGHT ...
OVER-RUNNING FRONT-END THUMP EVENT CENTERED AROUND MIDNIGHT TUESDAY
AND THROUGH THE DAY. BROADLY SPEAKING...LARGE-SCALE ASCENT OF THE
WARM-MOIST CONVEYOR BELT ACROSS SHALLOW COLD AIR MAINTAINED BY A
DOMINANT PRESENCE OF A 1040 HIGH IMMEDIATELY N/E. MAJORITY OF THE
FORCING APPEARS CONFINED WITHIN THE LOW-MID LEVELS AIDED BY
H925-85 CONVERGENCE / FRONTOGENESIS AND MID-LEVEL ENERGY SWEEPING
N FROM THE OHIO RIVER VALLEY BENEATH BROADER DIFFLUENCE UP AGAINST
A PREVAILING RIDGE. A BROAD PRECIPITATION SHIELD IS EXPECTED WITH
A SHARP NW-SE GRADIENT ALONG ITS LEADING EDGE.
GOING DEEPER...NAM IS SLIGHTLY FASTER WITH THE H8-7 WARM-NOSE AND
LESSER ON THE STRENGTH AND DEPTH OF COLDER AIR FROM THE 1040 HIGH
THOUGH THE STRENGTH AND PROXIMITY OF THE HIGH ARE SUCCINCT BETWEEN
ALL AVAILABLE GUIDANCE. NAM MEANWHILE KEEPS SURFACE SUB-FREEZING
AIR TRAPPED LONGEST DESPITE A SIMILAR MAGNITUDE OF H975-925
AGEOSTROPHIC FLOW OUT OF THE N/NE AS WELL AS TRACK AND DEVELOPMENT
OF THE NEAR- SHORE LOW. NOT SURPRISING CONSIDERING THE HIGH
RESOLUTION. OVERALL ALL OTHER FIELDS ARE IN DECENT AGREEMENT.
IMPORTANTLY...SOLUTIONS SUCCINCT ON THE PRESENCE OF ICE
CONCLUDING AROUND LATE-MORNING TO MIDDAY PERIOD AS DRIER AIR WORKS
IN FROM THE W.
EVALUATING PROBABILITIES...SREF CONFIDENT OF SNOW ACCUMULATION ON
AREA ROADWAYS AWAY FROM THE COAST. FOCUS FROM AROUND MIDNIGHT TO
MID- MORNING ALONG A STRING OF HIGHWAYS FROM THE MERRITT TO WILBUR
CROSS TO I-84 IN CT...FROM THERE I-90 TO THE I-95 BELTWAY ROUND
BOSTON. WPC PROBABILITIES WHILE BROAD INDICATE A SIGNIFICANT
ICING EVENT OVER N/W INTERIOR NEW ENGLAND...WITH SNOW
ACCUMULATIONS OF 2-4 INCHES OVER THE N-ZONES WITH POTENTIALLY
HIGHEST AMOUNTS OVER N WORCESTER / MIDDLESEX COUNTIES INTO
INTERIOR ESSEX. A LOW RISK AMOUNTS EXCEED WARNING CRITERIA.
MEANWHILE WITH CIPS ANALOGS...HIGH PROBABILITIES OF 2-4 INCHES
FROM S-BOSTON TO HARTFORD EXTENDING N WITH POTENTIALLY GREATER
THAN 4 OVER N/W MA. LOW RISK OF AMOUNTS GREATER THAN 6-INCHES. AT
LEAST HALF OF THE ANALOGS HAVE AT LEAST 6-HOURS OF FREEZING RAIN
OCCURRING OVER INTERIOR S NEW ENGLAND...WITH AT LEAST 1-HOUR
IMMEDIATELY AWAY FROM THE COASTAL PLAINS. GOOD PROBABILITIES OF
1-INCH LIQUID PRECIP AMOUNTS FOR S/SE-PORTIONS OF NEW ENGLAND ...
SUCCINCT WITH NEAR-SHORE LOW DEVELOPMENT AND CONVERGENT LOW-LEVEL
FLOW. ANALOGS PROG GUSTY WINDS OF 35 MPH FOR SE-COASTAL NEW
ENGLAND.
SO ALL IN ALL...NO SOLUTION CAN BE DISPUTED AS AN OUTLIER. PRECIP
BEGINNING AROUND MIDNIGHT OVERSPREADING SW TO NE. AGEOSTROPHIC
FLOW ONGOING WITH N-WINDS ACROSS THE INTERIOR WITH NE ALONG THE
SHORE. OVER TIME WITH COASTAL FRONT SETUP...WILL LIKELY SEE
FREEZING TEMPERATURES ERODE TOWARDS THE N/W AS WARMER AIR PUSHES
WITH ONSHORE FLOW ERODING THE COASTAL FRONT INTO THE INTERIOR.
LACK OF ICE ALOFT APPEARS LIKELY AROUND LATE-MORNING SO WILL
REMOVE ANY SNOW / SLEET MENTION DURING THIS TIMEFRAME.
GOING WITH A WINTER WEATHER ADVISORY...HOLDING SNOW ACCUMULATIONS
INCLUDING SLEET TIGHT AGAINST THE N-MASS BORDER AROUND 2-4 PERHAPS
SOME LOCALLY HIGHER AMOUNTS. A SLUSHY 1-2 ELSEWHERE EXCEPT FOR
S/SE- COAST AND COASTAL PLAINS OF NEW ENGLAND. AS FAR AS ICE A
POTENTIALLY MORE SIGNIFICANT IMPACT. COULD BE TALKING 0.1-0.2
INCHES IN SPOTS AS N-FLOW MAINTAINS FUNNELING COLDER AIR S. MAIN
CONCERN IS ON ELEVATED SURFACES...TREES / BRIDGES / WIRES.
THERE WILL LIKELY BE SOME SLIGHT CHANGES TO THE FORECAST AS WE GET
CLOSER IN TIME TO THE EVENT. BUT OVERALL THE TREND IS THERE ALONG
WITH ACCOMPANYING THREATS. BEST TO BE AWARE AND GET PREPARED.
WEDNESDAY THROUGH SUNDAY ...
HIGH PRESSURE BRIEFLY BUILDS OVER REGION WED. STAYED CLOSE TO
MODEL/ENSEMBLE CONSENSUS WHICH BRINGS NEXT SYSTEM ACROSS SOUTHERN
NEW ENGLAND THU. THIS LOOKS TO BE WARMER SOLUTION WITH BROAD S
FLOW IN PLACE...SO PTYPE NOT A CONCERN THIS TIME. SYSTEM IS
PROGRESSIVE AND WILL BE FOLLOWED BY MAINLY DRIER/SEASONABLE
WEATHER FRI THRU SUN.
&&
.AVIATION /03Z MONDAY THROUGH FRIDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH... GREATER THAN 60 PERCENT.
SHORT-TERM /THROUGH MONDAY/...
CONDITIONS IMPROVING VFR FROM NOW THROUGH 3Z. WINDS BACK OUT OF
THE N WITH GUSTS 20-25 KTS BEHIND A COLD FRONT SWEEPING S WITH
-RA / MVFR-LIFR CIGS AND VSBYS AHEAD. NO THREATS PER LLWS. N-WINDS
PERSIST THROUGH MONDAY WITH VFR.
KBOS TERMINAL...
WILL HOLD IFR CIGS FOR JUST THE NEXT HR. MAY END UP BEING LESS.
OTHERWISE BREEZY N-WINDS AND IMPROVING VFR.
KBDL TERMINAL...
VFR TRENDS PERSISTING. MAY SEE A TEMPO MVFR THE NEXT HOUR OR TWO.
OTHERWISE BREEZY N-WINDS AND A QUIET FORECAST UP THROUGH MONDAY
EVENING.
OUTLOOK /MONDAY NIGHT THROUGH FRIDAY/...
MONDAY NIGHT INTO TUESDAY...MODERATE CONFIDENCE.
MIX OF IFR-VLIFR. SNOW TRANSITIONING TO SLEET / FREEZING RAIN SW TO
NE DURING THE MORNING HOURS WITH A TRANSITION TO RAIN ALONG THE S/SE-
SHORES. SHOULD BE ALL RAIN BY AFTERNOON.
SNOW / ICE ACCUM OVER INTERIOR TERMINALS WILL BE SIGNIFICANT. AROUND
1-3 INCHES OF SNOW...AND A TENTH OR TWO OF ICE. N-WINDS ACROSS
THE INTERIOR...WITH BLUSTERY E-ONSHORE FLOW ALONG THE COAST WITH
GUSTS UP AROUND 35 KTS ESPECIALLY ALONG THE SE-COAST. BACKING NW
LATE.
WEDNESDAY THROUGH FRIDAY...MODERATE CONFIDENCE.
VFR WED. MVFR/IFR POSSIBLE IN RAIN THU. VFR FRI.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH... GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH MONDAY/...MODERATE CONFIDENCE.
N/NW WINDS INCREASE TONIGHT AS COLDER AIR ARRIVES BEHIND COLD
FRONT. EXPECT SOLID SCA WITH 25-30 KT GUSTS AND BUILDING SEAS.
LOW PROBABILITY OF REACHING MARGINAL GALES ON OUTER WATERS BUT
CONFIDENCE WAS NOT HIGH ENOUGH TO ISSUE GALE WARNINGS.
N WINDS SLOWLY DIMINISH MON AS HIGH PRESSURE BUILDS TO OUR N...
BUT IT WILL PROBABLY TAKE MOST OF DAY FOR WINDS TO SUBSIDE S AND E
OF NANTUCKET. THIS WILL MAINTAIN ROUGH SEAS ON OUTER WATERS
THROUGHOUT DAY WHILE SEAS ON NEARSHORE WATERS GRADUALLY SUBSIDE.
OUTLOOK /MONDAY THROUGH THURSDAY/...
MONDAY NIGHT INTO TUESDAY...MODERATE CONFIDENCE.
SNOW TRANSITIONING TO RAIN SW TO NE. LIKELY VISIBILITY IMPACTS. E-
WINDS INCREASING AS LOW PRESSURE DEVELOPS ALONG THE NEAR-SHORE.
GUSTS UP TO 40 KTS POSSIBLE DURING THE DAY...BACKING OUT OF THE
NW LATE. GALE WATCH ACCORDINGLY. CHOPPY SEAS WITH N-SWELL AND
E-WINDS. WAVES BUILD UP TO 10 FEET ON THE S-OUTER WATERS.
WEDNESDAY THROUGH FRIDAY...MODERATE CONFIDENCE.
HIGH PRESSURE BUILDS OVER REGION WED BEFORE NEXT SYSTEM BRINGS
INCREASING S WINDS AND BUILDING SEAS THU WHEN SCA CONDITIONS
POSSIBLE. DRIER/COLDER WEATHER FOLLOWS FRI WITH GRADUALLY
DIMINISHING WINDS AND SEAS.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...WINTER WEATHER ADVISORY FROM 8 PM MONDAY TO 1 PM EST TUESDAY
FOR CTZ002>004.
MA...WINTER WEATHER ADVISORY FROM 8 PM MONDAY TO 1 PM EST TUESDAY
FOR MAZ007-009-011>019.
WINTER WEATHER ADVISORY FROM 8 PM MONDAY TO 7 PM EST TUESDAY
FOR MAZ002>006-008-010-026.
RI...WINTER WEATHER ADVISORY FROM 8 PM MONDAY TO 1 PM EST TUESDAY
FOR RIZ001>004-006.
MARINE...GALE WATCH FROM LATE MONDAY NIGHT THROUGH TUESDAY EVENING FOR
ANZ231>237-250-251-254>256.
SMALL CRAFT ADVISORY UNTIL 7 PM EST MONDAY FOR ANZ231>234-250-
251-254>256.
SMALL CRAFT ADVISORY UNTIL 11 AM EST MONDAY FOR ANZ235-237.
&&
$$
SYNOPSIS...SIPPRELL/JWD
NEAR TERM...RLG/SIPPRELL/JWD
SHORT TERM...JWD
LONG TERM...SIPPRELL/JWD
AVIATION...SIPPRELL/JWD
MARINE...SIPPRELL/JWD
AREA FORECAST DISCUSSION
NWS NEW YORK NY
705 PM EST SUN DEC 27 2015
.SYNOPSIS...
A COLD FRONT WILL MOVE ACROSS BEFORE MIDNIGHT. HIGH PRESSURE WILL
BRIEFLY BUILD IN LATE TONIGHT...AND THEN SLOWLY RETREAT TO THE
NORTHEAST INTO TUESDAY. MEANWHILE...A WARM FRONT WILL APPROACH
FROM THE SOUTH MONDAY NIGHT...WITH AN AREA OF LOW PRESSURE
RIDING ALONG IT AND PASSING JUST TO THE SOUTH ON TUESDAY.
WEAK HIGH PRESSURE WILL BUILD IN TUESDAY NIGHT AND WEDNESDAY.
A FRONTAL SYSTEM WILL APPROACH WEDNESDAY NIGHT INTO THURSDAY.
WEAK HIGH PRESSURE WILL RETURN TO END THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
MADE MINOR CHANGES THIS UPDATE TO REFLECT THE LATEST TRENDS IN
OBSERVATIONS AND GUIDANCE. THE FORECAST APPEARS GENERALLY ON
TRACK.
MAIN CHANGE IS PER LATEST HRRR AND RADAR TRENDS BRING ALL
SHOWERS TO A CLOSE BY 5Z...WITH MOST OF THE AREA DONE BY 3Z. THIS
IS IN RESPONSE TO SLIGHTLY FASTER MOVEMENT OF 700-500 HPA
SHORTWAVE TROUGH THAN EXPECTED.
LOOKING UPSTREAM...APPEARS SHOULD GET FAIRLY RAPID DROP OF IN
TEMPERATURES AFTER MIDNIGHT...AS STRONG CANADIAN HIGH PRESSURE
BUILDS TOWARDS THE AREA. TEMPERATURES WILL DROP TO MOSTLY THE 30S
FOR LOWS.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/...
A DEEP LAYERED RIDGE BUILDS OVER THE AREA MONDAY...WITH ASSOCIATED
SUBSIDENCE KEEPING THINGS DRY. HOWEVER...SHOULD HAVE SUFFICIENT MID
TO UPPER LEVEL MOISTURE FOR MID AND HIGH CLOUDS. FOR HIGHS MONDAY
USED A BLEND OF MAV/ECS/MET GUIDANCE WITH NAM 2-METER TEMPERATURES
AND A MIX DOWN FROM 925-900 HPA PER BUFKIT SOUNDINGS. HIGHS SHOULD
BE AROUND NORMAL.
THE DEEP LAYERED RIDGE AXIS SLIDES TO THE NE MONDAY NIGHT...ALLOWING
FOR OVER RUNNING FLOW TO SET UP OVER THE REGION...WHICH CONTINUES
THROUGH MOST OF TUESDAY WITH THE SURFACE LOW FORECAST TO PASS JUST
TO THE S OF LONG ISLAND. WITH A RETREATING DAMMING HIGH HELPING TO
KEEP LOW LEVEL COLD AIR IN PLACE...ESPECIALLY OVER THE
INTERIOR...SHOULD SEE A WINTRY MIX MONDAY NIGHT. IN ADDITION A
NORTHERN STREAM TROUGH PASSES TO THE N ON TUESDAY.
NYC PROPER AND LONG ISLAND SHOULD EXPERIENCE A PERIOD OF SLEET
BEFORE CHANGING TO ALL RAIN DURING THE NIGHT...WITH LITTLE OR NO
SLEET ACCUMULATION EXPECTED. MOST OF NE NJ/S WESTCHESTER/COASTAL CT
ZONES SHOULD EXPERIENCE A LONGER PERIOD OF SLEET AND MAYBE A BRIEF
BOUT OF FREEZING RAIN BEFORE CHANGING TO ALL RAIN BY AROUND SUNRISE.
FARTHER N OVER THE CWA...EXPECT MORE PROLONGED SLEET/LIGHT FREEZING
RAIN...POSSIBLY EVEN WITH SOME SNOW TO START ACROSS INTERIOR SE CT.
THE PRECIPITATION THERE SHOULD CHANGE TO ALL RAIN BY MIDDAY TUESDAY.
BASED ON THE ABOVE...HAVE ISSUED A WINTER WEATHER ADVISORY FOR
INTERIOR S CT...ALL OF THE LOWER HUDSON VALLEY EXCEPT S WEST CHESTER
AND W PASSAIC COUNTY FROM 1Z-16Z TUESDAY. ALSO BASED ON THE ABOVE
EXPECT LITTLE OR NO IMPACT OVER NYC PROPER AND LONG ISLAND -
THOUGH CANNOT COMPLETELY RULE OUT A BRIEF PERIOD OF FREEZING RAIN.
IT IS MORE UNCERTAIN OVER THAT MIDDLE AREA DESCRIBED ABOVE AS TO
WHETHER OR NOT THERE WILL BE ANY WIDESPREAD ACCRETION OF ICE OR
NOT...SO COULD SEE REFINEMENT TO THE ADVISORY AREA WITH LATTER
SHIFTS. THE MAIN CAUSE FOR CONCERN HERE IS ALL MODELS HISTORICALLY
ERODE THE DAMMING HIGH AND HENCE SCOUR OUT THE LOW LEVEL COLD AIR
TOO QUICKLY...BUT GIVEN IN A CLIMATOLOGICAL PATTERN ON A WHOLE...NOT
WILLING TO MAKE TYPICAL CLIMATOLOGICAL ADJUSTMENTS AT THIS TIME.
MAIN LIMITING FACTOR ON PRECIPITATION AMOUNT MONDAY NIGHT IS THAT
WITH CORE OF 700-500 HPA ENERGY FORECAST TO STAY OVER THE GREAT
LAKES/ST LAWRENCE RIVER VALLEY MONDAY NIGHT/TUESDAY...PRECIPITATION
INTENSITY SHOULD BE MAINLY LIGHT THEN. A 60+ KT LOW LEVEL JET
PASSES JUST S OF LONG ISLAND ON TUESDAY...SO THIS SHOULD ENHANCE
RAINFALL THEN...ESPECIALLY ACROSS S ZONES.
FOR TEMPERATURES MONDAY NIGHT AND TUESDAY USED A BLEND OF
MAV/MET/ECS GUIDANCE AND NAM 2-METER TEMPERATURES...WEIGHED MORE
TOWARDS COOLER NAM TO REFLECT IMPACT OF EVAPORATIONAL COOLING AND
GFS TYPICALLY TOO FAST TO ERODE LOW LEVEL COLD AIR. TEMPERATURES
SHOULD RUN AROUND 5-10 DEGREES ABOVE NORMAL MONDAY NIGHT AND TUESDAY.
DEEP LAYERED RIDGING BUILDS BACK IN TUESDAY NIGHT...WITH MAINLY DRY
CONDITIONS AND DECREASING CLOUDINESS EXPECTED. FOR NOW THOUGH...DUE
TO SOME UNCERTAINTY IN TIMING OF SYSTEMS...HAVE SLIGHT CHANCE TO
CHANCE POPS IN EARLY TUESDAY EVENING. LOWS TUESDAY NIGHT ARE BASED
ON A BLEND OF MAV/MET GUIDANCE AND NAM 2-METER TEMPERATURES AND
SHOULD BE AROUND 10-15 DEGREES ABOVE NORMAL.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
FAIR WEATHER RETURNS FOR MUCH OF WEDNESDAY AS WEAK HIGH PRESSURE
REMAINS OVER THE REGION. THE NEXT FRONTAL SYSTEM SHOULD BRING RAIN
LATE WEDNESDAY AFTERNOON THROUGH THURSDAY. TEMPERATURES ARE EXPECTED
TO BE WARM ENOUGH FOR THE PRECIPITATION TO REMAIN RAIN THROUGHOUT
THE EVENT. WEAK HIGH PRESSURE THEN BUILDS BACK INTO THE REGION
THURSDAY NIGHT THROUGH SUNDAY PROVIDING MOSTLY DRY CONDITIONS.
TEMPS WILL BE ABOVE AVERAGE WEDNESDAY THROUGH FRIDAY...WITH HIGHS
FROM THE MID 40S TO LOWER 50S. TEMPERATURES THEN FALL TO NEAR NORMAL
SATURDAY AND SUNDAY WITH HIGHS IN THE UPPER 30S AND LOWER 40S.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
A COLD FRONT WILL MOVE ACROSS BEFORE MIDNIGHT. HIGH PRESSURE WILL
THEN BUILD IN OVERNIGHT THROUGH MONDAY AFTERNOON.
MAINLY MVFR CIGS AHEAD OF THE COLD FRONT WILL QUICKLY LIFT TO VFR
AFTER COLD FROPA...BUT SHOWERS JUST BEHIND THE FRONT COULD BRIEFLY
LOWER VSBY TO MVFR. MORE IMPORTANTLY...AFTER COLD FROPA WINDS
SHOULD SHIFT NW-NNW AND INCREASE TO 12-18 KT WITH GUSTS 20-25 KT.
GUSTS COULD DROP OFF LATE TONIGHT OUTSIDE OF THE NYC METRO.
AS THE HIGH PASSES TO THE NORTH...WINDS WILL VEER AROUND TO THE NE
AT 10-12 KT WITH GUSTS 15-20 KT FROM AFTER DAYBREAK INTO EARLY MON
AFTERNOON. GUSTS SHOULD DROP OFF BY MID AFTERNOON.
.OUTLOOK FOR 00Z TUE THROUGH FRI...
.MON NIGHT-TUE MORNING...IFR CONDS DEVELOPING FROM SW TO NE.
E-SE WINDS G20-30KT POSSIBLE. AS FOR PRECIP TYPE...FOR NYC METRO
AND KISP...RAIN/SLEET...CHANGING TO ALL RAIN JUST BEFORE DAYBREAK.
FOR KBDR/KGON...RAIN/SLEET...CHANGING TO ALL RAIN AFTER DAYBREAK.
FOR KHPN/KSWF...SLEET/FREEZING RAIN TRANSITIONING TO RAIN BY
LATE MORNING.
.TUE AFTERNOON-EVENING...IFR OR LOWER IN RAIN. LLWS POSSIBLE.
.LATE TUE NIGHT-WED MORNING...BECOMING VFR.
.WED AFTERNOON-THU MORNING...MVFR OR LOWER DEVELOPING LATE WED IN
RAIN.
.THU AFTERNOON-FRI...VFR.
&&
.MARINE...
MADE MINOR CHANGES THIS UPDATE TO REFLECT THE LATEST TRENDS IN
OBSERVATIONS AND GUIDANCE. THE FORECAST APPEARS ON TRACK.
VISIBILITIES CONTINUE TO IMPROVE BASED ON WEB CAMS...SO WILL
CANCEL MARINE DENSE FOG ADVISORY WITH THIS ISSUANCE.
OTHERWISE...A SMALL CRAFT ADVISORY REMAIN IN EFFECT FOR THE OCEAN
WATERS AS SEAS REMAIN ABOVE 5 FT. IN ADDITION...SOME GUSTS TO 25 KT
CAN NOT BE RULED OUT AHEAD OF AN APPROACHING COLD FRONT.
SMALL CRAFT CONDITIONS ARE EXPECTED ON THE COASTAL OCEAN
WATERS/E SOUND AND THE BAYS OF LONG ISLAND ON MONDAY. GALE GUSTS ARE
THEN POSSIBLE OVER ALL WATERS FROM MONDAY NIGHT INTO TUESDAY. AS A
RESULT HAVE EXPANDED THE SCA ON MONDAY TO INCLUDE THE E SOUND AND
BAYS OF LONG ISLAND...AND ISSUED A GALE WATCH FOR ALL WATERS FROM
MONDAY NIGHT INTO TUESDAY MORNING.
SCA CONDITIONS ARE THEN EXPECTED FOR THE REMAINDER OF TUESDAY. WINDS
SHOULD DIMINISH TO 10 KT OR LESS OVER THE NON-OCEAN WATERS BY
TUESDAY EVENING AND SUBSIDE BELOW SCA LEVELS ON THE COASTAL OCEAN
WATERS BY THEN. HOWEVER...SEAS ON THE COASTAL OCEAN WATERS SHOULD
REMAIN AT OR ABOVE SCA LEVELS TUESDAY NIGHT.
SOME LEFT OVER 5 FT SEAS WILL LINGER INTO WEDNESDAY...HOWEVER SEAS
WILL GRADUALLY DIMINISH THROUGH THE DAY...WITH QUIET CONDITIONS
EXPECTED WEDNESDAY AFTERNOON THROUGH FRIDAY. ANOTHER CHANCE OF SMALL
CRAFT CONDITIONS WILL OCCUR OVER THE WEEKEND AS WIND GUSTS INCREASE
ON COLD AIR ADVECTION.
&&
.HYDROLOGY...
QPF OF MAINLY LESS THAN A TENTH OF AN INCH EXPECTED THIS EVENING...THEN
DRY WEATHER THROUGH MONDAY.
AROUND 1 INCH OF QPF IS EXPECTED MONDAY NIGHT-TUESDAY AND POSSIBLY
INTO TUESDAY EVENING. ONLY MINOR PONDING OF WATER IN URBAN/POOR
DRAINAGE AREAS IS EXPECTED AT THIS TIME AS A RESULT.
&&
.TIDES/COASTAL FLOODING...
AN APPROACHING LOW PRESSURE SYSTEM MAY RESULT IN MINOR COASTAL
FLOODING IMPACTS DURING THE TUESDAY MORNING/EARLY AFTERNOON HIGH
TIDE CYCLE. SURGE OF 2 TO 2 1/2 FT IS NEEDED TO EXCEED MINOR
FLOODING THRESHOLDS. CURRENT TIDAL GUIDANCE SUGGEST THAT WATER
LEVELS WILL REMAIN BELOW MINOR THRESHOLDS FOR MOST AREAS...WITH A
MARGINAL THREAT TO TYPICALLY VULNERABLE AREAS ALONG THE SOUTH SHORE
BAYS OF LONG ISLAND/NYC.
MINOR ATLANTIC OCEAN BEACH EROSION IS ALSO POSSIBLE FROM AN E TO W
SWEEP OF 5 TO 7 FT SURF AND THE HIGHER WATER LEVELS.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...WINTER WEATHER ADVISORY FROM 8 PM MONDAY TO 11 AM EST TUESDAY
FOR CTZ005>008.
NY...WINTER WEATHER ADVISORY FROM 8 PM MONDAY TO 11 AM EST TUESDAY
FOR NYZ067>070.
NJ...WINTER WEATHER ADVISORY FROM 8 PM MONDAY TO 11 AM EST TUESDAY
FOR NJZ002.
MARINE...GALE WATCH FROM MONDAY EVENING THROUGH TUESDAY MORNING FOR
ANZ330-335-338-340-345-350-353-355.
SMALL CRAFT ADVISORY FROM 6 AM TO 6 PM EST MONDAY FOR ANZ330-
340-345.
SMALL CRAFT ADVISORY UNTIL 6 PM EST MONDAY FOR ANZ350-353-355.
&&
$$
SYNOPSIS...BC/MALOIT
NEAR TERM...BC/MALOIT
SHORT TERM...MALOIT
LONG TERM...BC
AVIATION...GOODMAN
MARINE...BC/MALOIT
HYDROLOGY...BC/MALOIT
TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS TAUNTON MA
633 PM EST SUN DEC 27 2015
.SYNOPSIS...
A COLD FRONT MOVING THROUGH THE REGION WILL MARK THE ENTRANCE OF
COLDER AIR INTO THE REGION TONIGHT AND MONDAY. A WINTRY MIX FOR
LATE MONDAY NIGHT INTO TUESDAY WILL MAKE FOR A HAZARDOUS TUESDAY
MORNING COMMUTE. A BRIEF REPRIEVE OCCURS WEDNESDAY...PRIOR TO
ANOTHER STORM SYSTEM ARRIVING THURSDAY WHICH SHOULD BRING RAIN.
DRY AND SEASONABLE WEATHER FOLLOWS FOR NEW YEAR/S WEEKEND.
&&
.NEAR TERM /THROUGH MONDAY/...
630 PM UPDATE ...
FOLLOWING HRRR TRENDS ... COLD FRONT SWEEPING S BEHIND WHICH DRIER
AIR AND SUBSIDENCE SHOULD PREVAIL. SHOULD SEE A GRADUAL CLEARING
OVERNIGHT AS COLD AIR ADVECTION PROCEEDS DROPPING LOWS DOWN INTO
THE MID- TO UPPER-20S ... LOW-30S TO THE S. SHOWERS / LOW CLOUDS /
FOG ALONG AND AHEAD OF THE COLD FRONT OTHERWISE. THIS ACTIVITY
SHOULD ONLY LAST THE NEXT COUPLE OF HOURS FOR FAR S NEW ENGLAND.
&&
.SHORT TERM /MONDAY NIGHT THROUGH 6 PM MONDAY/...
HIGH PRESSURE BUILDS ACROSS QUEBEC MON...RESULTING IN N/NE FLOW OF
COLD AIR INTO REGION. CROSS SECTIONS SHOW PLENTY OF DRY AIR DURING
MORNING WHICH GIVES WAY TO INCREASING HIGH AND EVENTUALLY MID
LEVEL MOISTURE LATER IN DAY. SO EXPECT PLENTY OF SUNSHINE TO
START BEFORE INCREASING CLOUDS IN AFTERNOON. MODEL 2M TEMPERATURES
DO NOT SUGGEST MUCH OF WARMUP WITH COLD ADVECTION AT LOWER
LEVELS...SO HIGHS SHOULD STAY IN 30S ACROSS MUCH OF SOUTHERN NEW
ENGLAND WITH PERHAPS SOME OF HIGHER TERRAIN STAYING IN UPPER 20S.
&&
.LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
*/ HIGHLIGHTS ...
- POTENTIALLY DANGEROUS FIRST WINTER STORM OF THE SEASON
- ROUGHLY 1-3 INCHES OF SNOW ... LOCALLY HIGHER ACROSS N-MASS
- ONE TO TWO TENTHS OF ICE POSSIBLE ESP ACROSS THE INTERIOR
- GREATEST CONCERN: ELEVATED ROADWAYS / TREES / POWERLINES
- TRAVEL IS NOT RECOMMENDED AROUND TUESDAY MORNING
*/ OVERVIEW ...
REITERATING ... FOCUS IS MAINLY UPON MONDAY NIGHT INTO TUESDAY.
EVALUATING DETERMINISTIC / PROBABALISTIC / ENSEMBLE / ANALOG
GUIDANCE ... ALL SIGNS POINT TO YES FOR AN ADVISORY-LEVEL WINTER
WEATHER EVENT. INITIAL SNOWS ARE ANTICIPATED WITH CHANGE OVER TO
SLEET ... THEN THEREAFTER IT IS APPEARING MORE LIKELY THAT ACROSS
THE INTERIOR WE WILL SEE A SIGNIFICANT ICING EVENT WITH A PROLONGED
PERIOD OF FREEZING RAIN.
OUR FIRST WINTER STORM OF THE SEASON IS NOT AN EASY ONE TO FORECAST.
NUMEROUS INTANGIBLES AND INGREDIENTS INVOLVED WHICH CAN EASILY SKEW
SNOW / SLEET / ICE ACCUMULATIONS ... NAMELY GROUND TEMPERATURES / A
COASTAL FRONT SETUP BETWEEN N-WINDS OVER THE INTERIOR AND E-ONSHORE
FLOW / THERMAL PROFILES ALOFT / AND PRECIPITATION INTENSITY.
PATIENCE AND AWARENESS IS OF THE UTMOST. THIS IS ONE MESSY FORECAST
AND HONESTLY IT IS NOT GOING TO BE PERFECT CONSIDERING THE MULTIPLE
PRECIPITATION TYPES BUT THE TAKEAWAY IS ITS SIGNIFICANCE. ONGOING
DURING THE OVERNIGHT INTO THE TUESDAY MORNING COMMUTE ... ONLY A
TRACE OF SNOW / ICE ACCUMULATION LEADS TO HAVOC ALONG ROADWAYS
ESPECIALLY THOSE THAT ARE ELEVATED.
ITS NOT SO MUCH THE ACCUMULATIONS THAT ARE IMPORTANT IN THIS RESPECT
BUT RATHER THE IMPACT OF WHICH SHOULD ENCOURAGE THE PUBLIC TO STAY
OFF AREA ROADWAYS FOR THIS TIMEFRAME. ICE ACCUMULATIONS ARE FORECAST
TO BE A MAJOR THREAT IN ADDITION TO THE SNOW / SLEET. MORE DETAILED
DISCUSSION BELOW.
*/ DISCUSSION ...
MONDAY NIGHT INTO TUESDAY NIGHT ...
OVER-RUNNING FRONT-END THUMP EVENT CENTERED AROUND MIDNIGHT TUESDAY
AND THROUGH THE DAY. BROADLY SPEAKING ... LARGE-SCALE ASCENT OF THE
WARM-MOIST CONVEYOR BELT ACROSS SHALLOW COLD AIR MAINTAINED BY A
DOMINANT PRESENCE OF A 1040 HIGH IMMEDIATELY N/E. MAJORITY OF THE
FORCING APPEARS CONFINED WITHIN THE LOW-MID LEVELS AIDED BY H925-85
CONVERGENCE / FRONTOGENESIS AND MID-LEVEL ENERGY SWEEPING N FROM THE
OHIO RIVER VALLEY BENEATH BROADER DIFFLUENCE UP AGAINST A PREVAILING
RIDGE. A BROAD PRECIPITATION SHIELD IS EXPECTED WITH A SHARP NW-SE
GRADIENT ALONG ITS LEADING EDGE.
GOING DEEPER ... NAM IS SLIGHTLY FASTER WITH THE H8-7 WARM-NOSE AND
LESSER ON THE STRENGTH AND DEPTH OF COLDER AIR FROM THE 1040 HIGH
THOUGH THE STRENGTH AND PROXIMITY OF THE HIGH ARE SUCCINCT BETWEEN
ALL AVAILABLE GUIDANCE. NAM MEANWHILE KEEPS SURFACE SUB-FREEZING AIR
TRAPPED LONGEST DESPITE A SIMILAR MAGNITUDE OF H975-925 AGEOSTROPHIC
FLOW OUT OF THE N/NE AS WELL AS TRACK AND DEVELOPMENT OF THE NEAR-
SHORE LOW. NOT SURPRISING CONSIDERING THE HIGH RESOLUTION. OVERALL
ALL OTHER FIELDS ARE IN DECENT AGREEMENT. IMPORTANTLY ... SOLUTIONS
SUCCINCT ON THE PRESENCE OF ICE CONCLUDING AROUND LATE-MORNING TO
MIDDAY PERIOD AS DRIER AIR WORKS IN FROM THE W.
EVALUATING PROBABILITIES ... SREF CONFIDENT OF SNOW ACCUMULATION ON
AREA ROADWAYS AWAY FROM THE COAST. FOCUS FROM AROUND MIDNIGHT TO MID-
MORNING ALONG A STRING OF HIGHWAYS FROM THE MERRITT TO WILBUR CROSS
TO I-84 IN CT ... FROM THERE I-90 TO THE I-95 BELTWAY ROUND BOSTON.
WPC PROBABILITES WHILE BROAD INDICATE A SIGNIFICANT ICING EVENT OVER
N/W INTERIOR NEW ENGLAND ... WITH SNOW ACCUMULATIONS OF 2-4 INCHES
OVER THE N-ZONES WITH POTENTIALLY HIGHEST AMOUNTS OVER N WORCESTER /
MIDDLESEX COUNTIES INTO INTERIOR ESSEX. A LOW RISK AMOUNTS EXCEED
WARNING CRITERIA.
MEANWHILE WITH CIPS ANALOGS ... HIGH PROBABILITIES OF 2-4 INCHES
FROM S-BOSTON TO HARTFORD EXTENDING N WITH POTENTIALLY GREATER THAN
4 OVER N/W MA. LOW RISK OF AMOUNTS GREATER THAN 6-INCHES. AT LEAST
HALF OF THE ANALOGS HAVE AT LEAST 6-HOURS OF FREEZING RAIN OCCURRING
OVER INTERIOR S NEW ENGLAND ... WITH AT LEAST 1-HOUR IMMEDIATELY
AWAY FROM THE COASTAL PLAINS. GOOD PROBABILITIES OF 1-INCH LIQUID
PRECIP AMOUNTS FOR S/SE-PORTIONS OF NEW ENGLAND ... SUCCINCT WITH
NEAR-SHORE LOW DEVELOPMENT AND CONVERGENT LOW-LEVEL FLOW. ANALOGS
PROG GUSTY WINDS OF 35 MPH FOR SE-COASTAL NEW ENGLAND.
SO ALL IN ALL ... NO SOLUTION CAN BE DISPUTED AS AN OUTLIER. PRECIP
BEGINNING AROUND MIDNIGHT OVERSPREADING SW TO NE. AGEOSTROPHIC FLOW
ONGOING WITH N-WINDS ACROSS THE INTERIOR WITH NE ALONG THE SHORE.
OVER TIME WITH COASTAL FRONT SETUP ... WILL LIKELY SEE FREEZING
TEMPERATURES ERODE TOWARDS THE N/W AS WARMER AIR PUSHES WITH ONSHORE
FLOW ERODING THE COASTAL FRONT INTO THE INTERIOR. LACK OF ICE ALOFT
APPEARS LIKELY AROUND LATE-MORNING SO WILL REMOVE ANY SNOW / SLEET
MENTION DURING THIS TIMEFRAME.
GOING WITH A WINTER WEATHER ADVISORY ... HOLDING SNOW ACCUMULATIONS
INCLUDING SLEET TIGHT AGAINST THE N-MASS BORDER AROUND 2-4 PERHAPS
SOME LOCALLY HIGHER AMOUNTS. A SLUSHY 1-2 ELSEWHERE EXCEPT FOR S/SE-
COAST AND COASTAL PLAINS OF NEW ENGLAND. AS FAR AS ICE A POTENTIALLY
MORE SIGNIFICANT IMPACT. COULD BE TALKING 0.1-0.2 INCHES IN SPOTS AS
N-FLOW MAINTAINS FUNNELING COLDER AIR S. MAIN CONCERN IS ON ELEVATED
SURFACES ... TREES / BRIDGES / WIRES.
THERE WILL LIKELY BE SOME SLIGHT CHANGES TO THE FORECAST AS WE GET
CLOSER IN TIME TO THE EVENT. BUT OVERALL THE TREND IS THERE ALONG
WITH ACCOMPANYING THREATS. BEST TO BE AWARE AND GET PREPARED.
WEDNESDAY THROUGH SUNDAY ...
HIGH PRESSURE BRIEFLY BUILDS OVER REGION WED. STAYED CLOSE TO
MODEL/ENSEMBLE CONSENSUS WHICH BRINGS NEXT SYSTEM ACROSS SOUTHERN
NEW ENGLAND THU. THIS LOOKS TO BE WARMER SOLUTION WITH BROAD S
FLOW IN PLACE...SO PTYPE NOT A CONCERN THIS TIME. SYSTEM IS
PROGRESSIVE AND WILL BE FOLLOWED BY MAINLY DRIER/SEASONABLE
WEATHER FRI THRU SUN.
&&
.AVIATION /23Z SUNDAY THROUGH FRIDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH... GREATER THAN 60 PERCENT.
SHORT-TERM /THROUGH MONDAY/ ...
CONDITIONS IMPROVING VFR FROM NOW THROUGH 3Z. WINDS BACK OUT OF
THE N WITH GUSTS 20-25 KTS BEHIND A COLD FRONT SWEEPING S WITH
-RA / MVFR-LIFR CIGS AND VSBYS AHEAD. NO THREATS PER LLWS. N-WINDS
PERSIST THROUGH MONDAY WITH VFR.
KBOS TERMINAL...
WILL HOLD IFR CIGS FOR JUST THE NEXT HR. MAY END UP BEING LESS.
OTHERWISE BREEZY N-WINDS AND IMPROVING VFR.
KBDL TERMINAL...
VFR TRENDS PERSISTING. MAY SEE A TEMPO MVFR THE NEXT HOUR OR TWO.
OTHERWISE BREEZY N-WINDS AND A QUIET FORECAST UP THROUGH MONDAY
EVENING.
OUTLOOK /MONDAY NIGHT THROUGH FRIDAY/...
MONDAY NIGHT INTO TUESDAY ... MODERATE CONFIDENCE.
MIX OF IFR-VLIFR. SNOW TRANSITIONING TO SLEET / FREEZING RAIN SW TO
NE DURING THE MORNING HOURS WITH A TRANSITION TO RAIN ALONG THE S/SE-
SHORES. SHOULD BE ALL RAIN BY AFTERNOON.
SNOW / ICE ACCUM OVER INTERIOR TERMINALS WILL BE SIGNIFICANT. AROUND
1-3 INCHES OF SNOW ... AND A TENTH OR TWO OF ICE. N-WINDS ACROSS
THE INTERIOR ... WITH BLUSTERY E-ONSHORE FLOW ALONG THE COAST WITH
GUSTS UP AROUND 35 KTS ESPECIALLY ALONG THE SE-COAST. BACKING NW
LATE.
WEDNESDAY THROUGH FRIDAY ... MODERATE CONFIDENCE.
VFR WED. MVFR/IFR POSSIBLE IN RAIN THU. VFR FRI.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH... GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH MONDAY/ ... MODERATE CONFIDENCE.
N/NW WINDS INCREASE TONIGHT AS COLDER AIR ARRIVES BEHIND COLD
FRONT. EXPECT SOLID SCA WITH 25-30 KT GUSTS AND BUILDING SEAS.
LOW PROBABILITY OF REACHING MARGINAL GALES ON OUTER WATERS BUT
CONFIDENCE WAS NOT HIGH ENOUGH TO ISSUE GALE WARNINGS.
N WINDS SLOWLY DIMINISH MON AS HIGH PRESSURE BUILDS TO OUR N...
BUT IT WILL PROBABLY TAKE MOST OF DAY FOR WINDS TO SUBSIDE S AND E
OF NANTUCKET. THIS WILL MAINTAIN ROUGH SEAS ON OUTER WATERS
THROUGHOUT DAY WHILE SEAS ON NEARSHORE WATERS GRADUALLY SUBSIDE.
OUTLOOK /MONDAY THROUGH THURSDAY/ ...
MONDAY NIGHT INTO TUESDAY ... MODERATE CONFIDENCE.
SNOW TRANSITIONING TO RAIN SW TO NE. LIKELY VISIBILITY IMPACTS. E-
WINDS INCREASING AS LOW PRESSURE DEVELOPS ALONG THE NEAR-SHORE.
GUSTS UP TO 40 KTS POSSIBLE DURING THE DAY ... BACKING OUT OF THE NW
LATE. GALE WATCH ACCORDINGLY. CHOPPY SEAS WITH N-SWELL AND E-WINDS.
WAVES BUILD UP TO 10 FEET ON THE S-OUTER WATERS.
WEDNESDAY THROUGH FRIDAY ... MODERATE CONFIDENCE.
HIGH PRESSURE BUILDS OVER REGION WED BEFORE NEXT SYSTEM BRINGS
INCREASING S WINDS AND BUILDING SEAS THU WHEN SCA CONDITIONS
POSSIBLE. DRIER/COLDER WEATHER FOLLOWS FRI WITH GRADUALLY
DIMINISHING WINDS AND SEAS.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...WINTER WEATHER ADVISORY FROM 8 PM MONDAY TO 1 PM EST TUESDAY
FOR CTZ002>004.
MA...WINTER WEATHER ADVISORY FROM 8 PM MONDAY TO 1 PM EST TUESDAY
FOR MAZ007-009-011>019.
WINTER WEATHER ADVISORY FROM 8 PM MONDAY TO 7 PM EST TUESDAY
FOR MAZ002>006-008-010-026.
RI...WINTER WEATHER ADVISORY FROM 8 PM MONDAY TO 1 PM EST TUESDAY
FOR RIZ001>004-006.
MARINE...GALE WATCH FROM LATE MONDAY NIGHT THROUGH TUESDAY EVENING FOR
ANZ231>237-250-251-254>256.
SMALL CRAFT ADVISORY UNTIL 7 PM EST MONDAY FOR ANZ231>234-
254>256.
SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR ANZ236.
SMALL CRAFT ADVISORY UNTIL 11 AM EST MONDAY FOR ANZ235-237.
SMALL CRAFT ADVISORY UNTIL 7 PM EST MONDAY FOR ANZ250.
SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 7 PM EST
MONDAY FOR ANZ251.
&&
$$
SYNOPSIS...SIPPRELL/JWD
NEAR TERM...SIPPRELL/JWD
SHORT TERM...JWD
LONG TERM...SIPPRELL/JWD
AVIATION...SIPPRELL/JWD
MARINE...SIPPRELL/JWD
CLIMATE...
AREA FORECAST DISCUSSION
NWS TAUNTON MA
333 PM EST SAT DEC 26 2015
.SYNOPSIS...
A STORM SYSTEM BRINGS PERIODS OF RAIN AND AREAS OF FOG TO THE
REGION LATE TONIGHT INTO SUNDAY. HIGH PRESSURE WILL BRING COLDER
AIR INTO THE REGION LATE SUNDAY NIGHT INTO MONDAY. A WINTRY MIX
FOR LATE MONDAY NIGHT ON INTO TUESDAY WHICH WILL POSE HAZARDS FOR
THE TUESDAY MORNING COMMUTE ESPECIALLY. PERHAPS A BRIEF REPRIEVE
PRIOR TO ANOTHER STORM SYSTEM THROUGH THE AREA ON THURSDAY.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
MAIN ISSUE IS TIMING OF PRECIPITATION ONSET. LATEST HRRR HAS RAIN
APPROACHING THE CT RIVER VALLEY AROUND 06Z. ALTHOUGH THERE COULD BE
SPRINKLES PRIOR TO THAT TIME...IT WILL TAKE A WHILE TO OVERCOME DRY
AIR BELOW THE CLOUD BASE AND SATURATE THE COLUMN. BELIEVE THE
MEASURABLE RAIN WILL REACH THE E COAST AROUND OR SHORTLY AFTER 08Z.
THICKENING CLOUDS SHOULD LIMIT RADIATIONAL COOLING. COULD SEE TEMPS
REACH DOWN AT MOST INTO THE MID 30S IN A FEW SPOTS ACROSS FRANKLIN
AND NW WORCESTER COUNTIES...AND DO NOT PERCEIVE A FREEZING RAIN RISK
TONIGHT. FEEL CONFIDENT IN CATEGORICAL POPS FOR LATE TONIGHT.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
SUNDAY...MOST OF FORECAST AREA SHOULD START OUT WITH RAIN FALLING
BUT PRECIPITATION SHOULD TAPER OFF TO SCATTERED SHOWERS OR PATCHY
DRIZZLE BY AFTERNOON. COLUMN STAYS QUITE MOIST ACROSS NORTHERN ZONES
BUT POSSIBILITY OF A FEW BREAKS OF SUNSHINE S OF THE MASS PIKE.
ANOMALOUSLY WARM AIR MASS BUT THINK CLOUDS WILL PROBABLY HOLD MAX
TEMPS IN THE LOW TO MID 50S ACROSS NORTHERN MA. ACROSS CT...RI AND
SE MA...MAY SEE TEMPS JUMP INTO THE LOWER 60S DURING THE
AFTERNOON...AND HI TEMP RECORDS IN PROVIDENCE AND HARTFORD HAVE
A CHANCE OF BEING REACHED OR EXCEEDED.
SUNDAY NIGHT...GOOD MODEL CONSISTENCY OF COLD FRONT PASSING THROUGH
SOUTHERN NEW ENGLAND IN THE EARLY EVENING...FOLLOWED BY CLEARING AND
STEADILY DROPPING TEMPERATURES AND DEWPOINTS OVERNIGHT. N WIND
SHOULD GIVE NOTICEABLE BRISK FEEL TO THE AIR.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
*/ HIGHLIGHTS ...
- WINTRY MIX BEGINNING AFTER MIDNIGHT TUESDAY AND THROUGH THE DAY
- ADVISORY LEVEL SNOWS N OF THE MASS-PIKE FAVORED
- INTERIOR MIX-OVER TO SLEET AND FREEZING RAIN
- MIX-OVER FROM SNOW TO RAIN ALONG THE SHORES
*/ OVERVIEW ...
MAJORITY OF DISCUSSION FOCUSED ON THE EARLY WEEK PERIOD EVALUATING
UPON MULTIPLE PIECES OF FORECAST GUIDANCE: ENSEMBLE PROBABILITIES
AND THREATS / CIPS ANALOGS / DETERMINISTIC TRENDS AND OUTPUT.
INTANGIBLES TO CONSIDER WHICH WILL LIKELY RESULT IN AN INDIRECT
MEASURE OF IMPACT OF THE STORM ITSELF: PROLONGED PERIOD OF 2-MONTHS
OF WELL-ABOVE AVERAGE TEMPERATURES / WATERS WARMER THAN NORMAL THAT
REQUIRE A LOT OF LATENT HEAT RELEASE TO FALL AT OR BELOW FREEZING /
2-5 CM SOIL TEMPERATURES AROUND THE UPPER 40S TO LOW 50S / A COASTAL
FRONT SETUP BETWEEN N INTERIOR AGEOSTROPHIC-ISALLOBARIC FLOW AGAINST
ONSHORE E-FLOW / ABSENCE OF ICE ALOFT TOWARDS THE END OF THE STORM
AS DRIER AIR WORKS IN ALOFT / PRECIPITATION INTENSITY / WET-BULB
TEMPERATURES.
LOOKING LIKE A SOLID ADVISORY-LEVEL EVENT. MAIN CONCERNS: ELEVATED
SURFACES /I.E. BRIDGES/ WHICH ARE FIRST TO FREEZE AS WELL AS IMPACTS
TAKING PLACE DURING THE TUESDAY MORNING COMMUTE AND LINGERING INTO
THE AFTERNOON AND EVENING.
OVERALL ... FORGET ABOUT ACCUMULATIONS AND WHAT IS GOING TO HAPPEN
IN YOUR BACKYARD SPECIFICALLY. FOCUS ON THE IMPACTS AND TRENDS ...
THE TIMING OF ASSOCIATED HAZARDS. IT TAKES ONLY A TRACE OF SNOW
AND/OR ICE TO MAKE ROADS SLICK. ADDITIONAL AMOUNTS ONLY MAGNIFY THE
MAGNITUDE OF THE IMPACT ... BUT THE THREAT TO LIFE AND PROPERTY IS
MOSTLY THE SAME WITH RESPECT TO THIS EVENT ... ESPECIALLY ALONG AREA
ROADWAYS.
WILL EXTEND ON FORECAST THINKING / SPECIFICS IN THE DISCUSSION BELOW.
*/ DISCUSSION ...
MONDAY ...
QUIET WITH COLD AIR IN PLACE PER 1040 CANADIAN HIGH PRESSURE TO THE
N. N-WINDS DRIVING COLDER AIR S. INCREASING CLOUDS THROUGH THE DAY
LOWERING AND THICKENING WITH TIME. DRY FORECAST. COOLER THAN AVERAGE
DAY ... FINALLY A TOUCH OF WINTER ... WITH HIGHS AROUND THE MID-30S.
MONDAY NIGHT INTO TUESDAY NIGHT ...
BROADSCALE OVER-RUNNING EVENT. FORCING / LIFT OF AVAILABLE MOISTURE
IS NOT OUT OF THE QUESTION AS THE THERMAL PROFILE TRANSITIONS FROM
COLD TO WARM ... AND SHALLOW SURFACE COLD AIR IS GRADUALLY SCOURED
OUT ... A LIKELY WINTRY MESS BEGINNING AFTER MIDNIGHT AND THROUGH
THE DAY TUESDAY.
NAM APPEARS THE OUTLIER. HOLDING COLDER AIR IN LONGER WITHIN THE LOW-
TO MID-LEVELS WHILE HOLDING DRIER AIR TO THE W KEEPING ICE PRESENT
THROUGH MUCH OF THE DAY TUESDAY ... WHEREAS THE GFS/EC TRANSITION
DURING THE MORNING PERIOD AND ICE BECOMES ABSENT AROUND MID-MORNING.
SIMILAR TRENDS OBSERVED WITH SURFACE 2M TEMPERATURES AND DEWPOINTS
WITH THE NAM HOLDING COLDER AND DRIER AIR IN LONGER OVER THE GFS/EC.
DOES NOT MAKE ABSOLUTE SENSE CONSIDERING THE CANADIAN HIGH SHIFTING
E AND THE LIKELY VEERING OF AGEOSTROPHIC FLOW OUT OF THE E AS WELL
OFF THE WARMER OCEAN WATERS.
THIS MAY ALL BE DUE TO THE VARIABILITY OF THE STRENGTH AND EVOLUTION
OF N-AND S-STREAM LOW CENTERS. NAM APPEARS MORE STOUT WHEREAS THE
GFS/EC DEAMPLIFIES THE H5 IMPULSE OUT OF THE SW-CONUS WHICH MAKES
MORE SENSE BASED ON THE BROADER-SCALE PATTERN AS OF LATE OF MORE
FAVORABLE RIDGING OVER THE E-CONUS. EVEN CONVERGENT LOW-LEVEL WIND
FIELDS DIFFER BETWEEN THE TWO CAMPS OF THE NAM AND GFS/EC.
WILL LEAN A GFS/EC BLEND WITH THIS FORECAST. TRANSITION THE LOW- TO
MID-LEVELS WARMER DURING THE MORNING WHILE USHERING DRIER AIR FROM
THE W. GRADUAL EROSION OF COLDER AIR AT THE SURFACE N/E AS A COASTAL
FRONT SETUP PUSHES N. THIS SUBSEQUENT AS THE AGEOSTROPHIC FLOW NEAR
THE SURFACE VEERS E OVER TIME ... ESPECIALLY WITH HEIGHT ... AS THE
CANADIAN HIGH SHIFTS TO THE E.
SO INITIAL SNOWS CHANGING TO SLEET DURING THE EARLY- TO MID-MORNING
SW TO NE ... THEN CHANGING OVER TO FREEZING RAIN ACROSS THE INTERIOR
FOR THOSE LOCALES BELOW FREEZING AS WARMER AIR INTRUDES ALOFT AND
ICE BECOMES ABSENT. MAY VERY WELL BE DURING THE INITIAL DEVELOPMENT
PHASE OF THE COASTAL FRONT THAT SHORE-LINE COMMUNITIES SIMPLY CHANGE
FROM SNOW TO RAIN. ALL LOCATIONS CHANGED OVER TO RAIN BY MID- TO
LATE-AFTERNOON.
EVALUATING PROBABILITIES ... ADVISORY-LEVEL SNOWS ARE FAVORED ALONG
AND N OF THE MASS-PIKE WITH A LOW-RISK OF WARNING LEVEL SNOWS OVER N
MASS. A DECENT SLEET POSSIBILITY WITH THE POTENTIAL FOR A PROLONGED
PERIOD OF FREEZING RAIN PERHAPS GREATER THAN 6-HOURS AS SUGGESTED
PER CIPS ANALOGS. WILL UPDATE OUR WINTER WEATHER WEBPAGE ACCORDINGLY.
NOT OVERLY CONFIDENT WITH THE SNOW- AND ICE-TOTAL OUTPUT ... FEEL
THERE IS GOING TO BE SOME FLUX OF LESSER TOTALS ALONG THE IMMEDIATE
E-COAST WITH BRISK ONSHORE FLOW. IN IS IN THESE AREAS THAT ALSO TOO
SNOW MAY SIMPLY CHANGE TO RAIN. AS WE GET HIGHER-RES GUIDANCE AND
CLOSER TO THE EVENT ... SHOULD HAVE A BETTER HANDLE OVERALL.
NO HAZARDS AT THIS TIME. CONTINUED MENTION IN THE HAZARDOUS WEATHER
OUTLOOK. PLEASE SEE THE OVERVIEW ABOVE FOR THE BROADER OVERVIEW OF
CONCERNS AND CHALLENGES TO THIS FORECAST.
WEDNESDAY THROUGH FRIDAY...
HIGH PRESSURE GIVES US A BREAK ON WEDNESDAY. THE NEXT SHORTWAVE
RACES THROUGH THE UPPER FLOW AND BRINGS PRECIPITATION OUR WAY
THURSDAY. LOW CONFIDENCE ON STORM TRACK...WITH TEMPERATURES
BORDERLINE FOR ICE INLAND...BUT MAINLY RAIN EXPECTED OVER OUR AREA.
DRY WEATHER RETURNS FOR FRIDAY.
&&
.AVIATION /21Z SATURDAY THROUGH THURSDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH SUNDAY NIGHT/...
TONIGHT...MODERATE TO HIGH CONFIDENCE. ANTICIPATING VFR CONDITIONS
TO PREVAIL MOST OF THE EVENING BUT STARTING TO DETERIORATE TOWARD
MIDNIGHT CT RIVER VALLEY AND THE EAST SLOPES OF THE BERKSHIRES. MVFR
CIGS AND VSBYS IN RAIN AND FOG WILL SPREAD EAST TO REACH THE MA EAST
COAST AROUND 08Z OR 09Z. AREAS OF IFR CIGS/VSBYS LIKELY DEVELOPING
TOWARD DAYBREAK FROM WEST TO EAST.
SUNDAY...MODERATE CONFIDENCE. WIDESPREAD IFR CIGS AND MVFR VSBYS
WITH AREAS OF IFR VSBYS IN RAIN AND FOG IN THE MORNING IMPROVING TO
MVFR OR LOW VFR CIGS IN THE AFTERNOON.
SUNDAY NIGHT...HIGH CONFIDENCE. AREAS OF MVFR CIGS LINGERING DURING
THE EVENING ACROSS CT...RI AND SE MA BUT BECOMING VFR OVERNIGHT.
KBOS TERMINAL...MODERATE TO HIGH CONFIDENCE IN TAF. VFR CONDITIONS SHOULD
PERSIST TO ABOUT 08Z AND THEN LOWERING TO MVFR CIGS/VSBYS AND LIKELY
IFR CIGS/VSBYS BY DABREAK IN RAIN AND FOG. IMPROVING TO MVFR OR LOW
VFR CIGS DURING THE AFTERNOON.
KBDL TERMINAL...MODERATE TO HIGH CONFIDENCE IN TAF. EXPECT VFR CONDITIONS
TO PREVAIL THROUGH ABOUT 05Z AND THEN DETERIORATING THEREAFTER AS
PER TAF.
OUTLOOK /MONDAY THROUGH THURSDAY/...
MONDAY ... HIGH CONFIDENCE.
VFR. BLUSTERY N-WINDS WITH GUSTS TO 25 KTS ALONG THE CAPE / ISLANDS
GRADUALLY VEERING NE.
MONDAY NIGHT INTO TUESDAY ... MODERATE CONFIDENCE.
MIX OF MVFR-VLIFR. SNOW TRANSITIONING TO SLEET / FREEZING RAIN SW TO
NE WITH A TRANSITION TO RAIN ALONG THE SHORES. SNOW / ICE ACCUM
LIKELY OVER INTERIOR TERMINALS. N-WINDS ACROSS THE INTERIOR WITH
BLUSTERY ONSHORE FLOW WITH GUSTS UP TO 30 KTS ALONG THE COAST.
BACKING NW LATE.
WEDNESDAY ... MODERATE CONFIDENCE.
VFR. LIGHT AND VARIABLE WINDS.
THURSDAY ... LOW CONFIDENCE.
ANOTHER STORM SETUP WITH A MIX OF MVFR-IFR CONDITIONS AND RAIN.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH SUNDAY NIGHT/...MODERATE CONFIDENCE
MODERATE TO HIGH CONFIDENCE.
REST OF THIS AFTERNOON AND TONIGHT...SEAS HAVE FINALLY DROPPED BELOW
5 FEET AT BUOY 44018 BUT REMAINING 5 TO 7 FEET ACROSS NANTUCKET
SHOALS AS WELL AS THE WATERS S OF LONG ISLAND. WILL START THE SCA
HEADLINE FOR THE OUTER SOUTH COAST WATERS LATE THIS AFTERNOON TO
ACCOUNT FOR CURRENT CONDITIONS.
SUNDAY...SW GRADIENT STRENGTHENS ON SUNDAY AND WILL KEEP THE SCA
HEADLINE UP FOR THE BLOCK ISLAND AND RI SOUNDS.
SUNDAY NIGHT...N TO NNE WIND INCREASES BEHIND DEPARTING LOW AND COLD
FRONT. SURFACE GRADIENT COUPLED WITH MODERATELY STRONG COLD
ADVECTION WILL LIKELY RESULT IN WIND GUSTS 25 TO 30 KT ACROSS MOST
OF THE WATERS DEVELOPING SOMETIME SUNDAY NIGHT. THIS IS FAR ENOUGH
AHEAD AND SO WILL HOLD OFF ON HEADLINES FOR NOW BUT PROBABLY NEEDED
BEFORE TOO LONG. THERE IS A SMALL RISK BUT WITH CONFIDENCE BELOW 50
PERCENT OF GALE GUSTS TOWARD DAYBREAK MONDAY.
ADJUSTED STORM SURGE UP FROM GUIDANCE FOR MONDAY AM TIME FRAME
BUT NOT ENOUGH TO CAUSE ANY COASTAL FLOOD CONCERNS.
OUTLOOK /MONDAY THROUGH THURSDAY/...MODERATE CONFIDENCE.
MONDAY ... HIGH CONFIDENCE.
BLUSTERY N-WINDS WITH GUSTS TO 25 KTS ALONG THE CAPE / ISLANDS
GRADUALLY VEERING NE. SEAS OF AROUND 6-8 FEET MAINTAIN ON THE OUTER
WATERS AND ALONG THE NEAR-SHORES TO THE E.
MONDAY NIGHT INTO TUESDAY ... MODERATE CONFIDENCE.
SNOW TRANSITIONING TO RAIN SW TO NE. LIKELY VISIBILITY IMPACTS. E-
WINDS INCREASING AS LOW PRESSURE DEVELOPS ALONG THE NEAR-SHORE.
GUSTS UP TO 30 KTS POSSIBLE DURING THE DAY ... BACKING OUT OF THE NW
LATE. CHOPPY SEAS WITH N-SWELL AND E-WINDS. WAVES BUILD UP TO 10
FEET ON THE S-OUTER WATERS.
WEDNESDAY ... MODERATE CONFIDENCE.
LIGHT AND VARIABLE WINDS BENEATH HIGH PRESSURE. SEAS ALLOWED TO
RELAX.
THURSDAY ... LOW CONFIDENCE.
ANOTHER STORM SETUP WITH RAIN. WINDS COULD BECOME BLUSTERY LENDING
TO WAVE HEIGHTS BACK UP TO 5-FEET.
&&
.CLIMATE...
RECORD HIGH TEMPERATURES FOR SUNDAY 12/27...
BOSTON 61/1949
PROVIDENCE59/1973
HARTFORD60/1949
WORCESTER 58/1895
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST SUNDAY FOR ANZ254>256.
SMALL CRAFT ADVISORY FROM NOON TO 6 PM EST SUNDAY FOR ANZ235-
237.
&&
$$
SYNOPSIS...SIPPRELL/THOMPSON
NEAR TERM...THOMPSON
SHORT TERM...THOMPSON
LONG TERM...SIPPRELL/THOMPSON
AVIATION...SIPPRELL/THOMPSON
MARINE...SIPPRELL/THOMPSON
CLIMATE...
AREA FORECAST DISCUSSION
NWS JACKSONVILLE FL
221 PM EST SAT DEC 26 2015
.NEAR TERM / THRU SUNDAY /...
MODEL GUIDANCE SUGGESTS LOW PROBABILITY OF SHOWERS LATE THIS
AFTERNOON AND EVENING SPREADING FROM S TO N. UNCERTAIN OF CAUSAL
MECHANISM FOR THE SHOWERS...WITH JUST GO WITH 20 POP INLAND AREAS
AND 30 POP COASTAL WATERS WHERE THERE ARE SOME WIDELY SCATTERED
SMALL SHOWERS.
ANOTHER CHALLENGING FORECAST OF LOW CLOUDS/FOG TONIGHT. HRRR NOT
AGGRESSIVE IN OUR FORECAST AREA...SREF SHOWING SOME POTENTIAL FOR
EASTERN SE GA COUNTIES WITH HIGHER PROBABILITIES OF LOW CLOUDINESS
ACROSS FORECAST AREA FROM I-10 NORTHWARD. MAY BE A LITTLE MORE IN
THE WAY OF WIND/MIXING JUST ABOVE THE SURFACE TO SUPPORT LOW
CLOUDS RATHER THAN DENSE FOG. FOR THIS FORECAST...WENT WITH
PATCHY FOG LATER TONIGHT...EXCEPT AREAS OF FOG ACROSS EASTERN HALF
OF OUR SE GA FORECAST AREA WHERE GREATER FOG POTENTIAL. ANOTHER
MILD NIGHT WITH LOW TEMPS IN THE MID TO UPPER 60S.
FOR SUNDAY...LOW CLOUDINESS AND PATCHY FOG IN THE MORNING SHOULD
GIVE WAY TO PARTLY CLOUDY SKIES WITH ANOTHER AFTERNOON OF NEAR
RECORD HIGH TEMPS...LOW-MID 80S INLAND...UPR 70S IMMEDIATE COAST.
.SHORT TERM...SUNDAY NIGHT THRU TUESDAY...SOUTHERN PLAINS LOW WILL
LIFT NE TO THE GREAT LAKES MONDAY NIGHT/TUESDAY WITH TRAILING COLD
FRONT STALLING JUST TO OUR NW. ISOLATED TO SCATTERED SHOWERS WILL BE
POSSIBLE OVER NE FL/SE GA AS MOISTURE INCREASES IN MID/UPPER LEVELS.
NEAR RECORD TEMPERATURES WILL PERSIST. HIGH HUMIDITY WILL ALSO
CONTINUE THE CHANCE FOR NIGHTLY FOG AND SEA FOG.
.LONG TERM...WEDNESDAY THROUGH SATURDAY...SURFACE FRONT WILL SHIFT
FURTHER NORTH OF THE AREA AS A LOW TO THE NW MOVES NE ALONG
BOUNDARY. AS SURFACE LOW AND UPPER TROUGH LIFT AWAY TO THE NE THE
FRONTAL BOUNDARY WILL SHIFT BACK TO THE SE REACHING SE GA LATE
THURSDAY. ADDITIONAL SHORT WAVE ENERGY WILL CARVE OUT A LONG WAVE
TROUGH OVER THE EAST THROUGH THE WEEKEND. THIS WILL ALLOW THE SLOW
MOVING COLD FRONT ACCOMPANIED BY SCATTERED TO NUMEROUS SHOWERS TO
MOVE ACROSS NE FL THURSDAY NIGHT BRINGING COOLER TEMPERATURES.
ABOVE NORMAL TEMPERATURES WEDNESDAY AND THURSDAY WILL COOL TO NEAR
AVERAGE LEVELS FOR THE NEW YEAR. POST FRONTAL RAIN WILL END FROM THE
NW BY FRIDAY NIGHT AS SHALLOW COLD FRONT SHIFTS SOUTH INTO S FL.
&&
.AVIATION...GENERALLY VFR CONDITIONS THROUGH EARLY EVENING. LATEST
MODEL GUIDANCE CONTINUES TO POINT TO DECENT POTENTIAL FOR LOW CIGS
TO DEVELOP BY LATE EVENING AND OVERNIGHT OVER TAF SITES...WITH
POTENTIAL FOR DENSE FOG KSSI BUT BETTER POTENTIAL FOR LOW CIGS
THAN DENSE FOG AT OTHER TAF SITES. NEVERTHELESS STILL ANTICIPATE
IFR CONDITIONS AT TAF SITES ESP 06-14Z. IMPROVING CONDITIONS
AFTER 14Z SUNDAY.
&&
.MARINE...INCREASING PRESSURE GRADIENT OVER WATERS BETWEEN HIGH
PRESSURE WELL NE OF WATERS AND DEVELOPING STORM SYSTEM OVER THE
SOUTHERN PLAINS WILL SUPPORT INCREASING WINDS AND SEAS. WILL GO
WITH EXERCISE CAUTION TONIGHT OFFSHORE COMPONENT FOR WINDS
INCREASING TO 15 KTS AND 4-6 FT SEAS. LITTLE CHANGE EXPECTED
THRU THE MIDDLE OF NEXT WEEK WITH CONTINUED S TO SE WINDS OVER
THE WATERS.
RIP CURRENTS: MODERATE RISK THIS WEEKEND.
.CLIMATE...
RECORD WARM MINIMUM TEMPS FOR DECEMBER 26TH...
JAX...66/1941...GNV...66/1964...AMG...65/1964...SSI...61/1987
RECORD MAX TEMPS FOR DECEMBER 26TH...
JAX...83/1987...GNV...82/2008...AMG...79/1987...SSI...79/1971
RECORD WARM MINIMUM TEMPS FOR DECEMBER 27TH...
JAX...68/1942...GNV...66/1911...AMG...62/2008...SSI...63/1982
RECORD MAX TEMPS FOR DECEMBER 27TH...
JAX...81/2008...GNV...84/1942...AMG...80/1987...SSI...78/1971
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG 66 82 64 82 / 20 10 10 40
SSI 65 77 61 75 / 30 10 40 30
JAX 67 83 67 81 / 20 10 20 30
SGJ 68 80 67 80 / 20 10 20 30
GNV 66 83 66 83 / 20 10 10 30
OCF 66 84 67 84 / 20 10 10 40
&&
.JAX WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GA...NONE.
AM...NONE.
&&
$$
WOLF/ZIBURA/GUILLET
AREA FORECAST DISCUSSION
National Weather Service Lincoln IL
912 PM CST SUN DEC 27 2015
.UPDATE...
ISSUED AT 855 PM CST SUN DEC 27 2015
00z ILX sounding showing a fairly substantial dry layer from
850 mb to 700 mb this evening and some of the dry air is working
on the rain shield that was making its ways northward over the
forecast area. Rainfall rates with this initial band were quite
light but expect those to start to pick later this evening and
as the low to mid level warm advection intensifies ahead of the
deep upper low currently over central Tx. The surface low will
track right across the region Monday afternoon and evening with
the most intense rainfall (freezing rain/sleet across the north)
Monday morning. RAP forecast soundings showing surface temps
supporting mostly a rain and sleet mix north before a transition
over to freezing rain in the 08z-10z time frame in Peoria, and
between 10z and 12z in Bloomington. As the precipitation works
its way north overnight, look for the easterly winds to increase
to between 25 to 35 mph with gusts of 45 to 50 mph possible Monday
morning as the pressure gradient really tightens up.
Have made some minor adjustments to the timing of the precip based
on evening trends along with some tweaks to the temps and winds.
Otherwise, no major changes to the going forecast, winter storm
warning and freezing rain advisory. We should have the updated
ZFP out by 920 pm.
&&
.SHORT TERM...(Tonight)
ISSUED AT 526 PM CST SUN DEC 27 2015
A somewhat narrow band of moderate to heavy rain continues along
the I-70 corridor this afternoon continuing to increase the
rainfall totals in that area...now already with many locations in
the 4+ inch range for rainfall between I-70 and I-74. This band
will shift northward overnight as the warm advection region aloft
pushes north with increasing southerly flow ahead of an intense
low over Texas lifts northward toward central IL. With Canadian
high pressure moving by to the north of the Great Lakes
overnight...northerly surface flow will bring temperatures to near
freezing overnight. A wedge of warm air at the 700 to 900 mb level
(2000-1000 feet) will push above the cold surface layer...and we
should see a mix of brief snow and sleet changing over to freezing
rain from around Fulton to McLean County northward. Progressively
heavier and more widespread precipitation will spread northward
through the early morning hours Monday as the low center
approaches. A winter storm warning is in effect for
Knox...Peoria...and Woodford counties northward 3 a.m. to 3 p.m.
Monday and a freezing rain advisory is in effect Midnight to noon
Monday from Fulton to Mclean County. In addition...strong NE winds
30-35 mph and gusts to around 50 mph will develop overnight as the
intense surface pressure gradients around the low approach. Any
ice accumulation on elevated objects such as
trees...powerlines...could be enhanced by the winds. Even without
ice accumulations...the winds would be strong enough to produce
minor tree damage and toss loose objects. A wind advisory is in
effect for these areas from Midnight to 6 p.m. Monday.
&&
.LONG TERM...(Monday through Sunday)
ISSUED AT 526 PM CST SUN DEC 27 2015
Widespread moderate to heavy precipitation rates and strong ENE
winds will continue much of the day Monday while surface
temperatures rise to gradually above freezing. I-74 as far east as
Bloomington should see the best chances for freezing rain
continuing until around noon...while to the south any freezing
rain should end by mid morning. Accumulations to around a quarter
inch I-74 northward in this area are likely...while more like a
tenth of an inch southward through Fulton...Tazewell...and Mclean
county are expected due to the shorter duration of freezing
temperatures. Farther south...only short durations of freezing
precipitation are expected although the additional 1.5 inches or
so of precipitation will exacerbate the flooding which is
prevalent south of I-72.
A northern stream weather system approaching the Pacific
Northwest will track into the Midwest by Wed morning and bring
small chances of light rain/snow showers to central IL on Wed.
Southeast IL looks drier now on Wed and wx system shifts ne of
central IL Wed night. Highs Wed to range from 30-35F nw of the IL
river to 40-45F from I-70 southeast.
Strong upper level trof dominates the northeast half of the country
during 2nd half of the week, while large Canadian high pressure
settling into the Rockies and high plains will bring an extended
period of below normal temperatures to IL for a change. The coldest
air will be over area on Thu/Fri with highs staying below freezing
for most of central/SE IL. Have partly cloudy skies Thu/Fri.
Highs will only modify slightly New Years weekend into the low to
mid 30s despite more sunshine.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
ISSUED AT 519 PM CST SUN DEC 27 2015
One more storm to go through over the next 24 hours with
additional rainfall and some freezing rain potential, especially
for PIA. The main impact with this storm not only will be with
the wintry precip across the north, but with strong easterly
winds tonight and especially on Monday as the storm moves towards
our area. Wind gusts of 40 to 45 kts possible on Monday out of
the east before winds slowly diminish after 21z as the storm
shifts off to our northwest by evening. The dry easterly flow
has eroded some of the lower clouds over the forecast area and
that should hold for several hours this evening at CMI, but
it appears as the rain moves from south to north this evening,
the low levels will gradually moisten and all areas should be
IFR to LIFR after 06z and continue thru the remainder of the
forecast period.
&&
.ILX Watches/Warnings/Advisories...
Flash Flood Watch through Monday afternoon for ILZ044>046-049-
050-052>057-061>063-066>068-071>073.
Wind Advisory from midnight tonight to 6 PM CST Monday for
ILZ027>031-036>038-040>057-061.
Winter Storm Warning from 3 AM to 3 PM CST Monday for ILZ027>031.
Flash Flood Watch through Monday evening for ILZ051.
Freezing Rain Advisory from midnight tonight to noon CST Monday
for ILZ036>038.
&&
$$
UPDATE...Smith
SHORT TERM...Geelhart
LONG TERM...Onton
AVIATION...Smith
AREA FORECAST DISCUSSION
National Weather Service Lincoln IL
540 PM CST SUN DEC 27 2015
.UPDATE...
ISSUED AT 1019 AM CST SUN DEC 27 2015
Northern edge of the rain shield continues to be shunted
southward, and was mainly south of a Danville to Taylorville line.
Some breaks have occurred even south of that area as well, but
rain continues to spread northeast out of southern Missouri.
Highest PoP`s through the afternoon will remain across areas along
and south of I-70, with mostly dry conditions north of I-72.
Temperatures will hold fairly steady over most of the CWA, but
will fall a bit more in the far southeast before holding steady
there as well. Updated zones/grids sent to refine the PoP and
temperature trends. The Flash Flood Watch remains in place,
although we have extended it for Sangamon County due to releases
occurring from Lake Springfield.
Early look at the morning run of the NAM model shows a substantial
warm wedge moving into the northern CWA associated with the 850 mb
warm front. Forecast sounding for Galesburg shows temperatures
near that level getting as high as 10C by late morning with the
surface temperatures staying just above freezing. The GFS is not
quite as prominent with that warm layer, but still reaches 5C,
enough to fully melt any precipitation going through that layer.
Numerical guidance from the NAM, GFS and LAMP show the lowest
temperatures occurring around 8-9 am before rising back up above
freezing. Will await early afternoon conference call with Weather
Prediction Center and their new guidance before making any
decisions on how to evolve the Winter Storm Watch.
&&
.SHORT TERM...(Today)
ISSUED AT 351 AM CST SUN DEC 27 2015
The band of steady rainfall is expected to gradually shift southward
today, putting more focus on our southern counties south of I-72.
Precipitation should become much lighter or end NW of the IL river
by afternoon. Embedded thunderstorms will shift south of our
forecast area this morning, as the warm front slides into southern
Illinois. RAP model forecast precipitable water values are expected
to gradually decrease from 1.4 inches down toward 0.9-1.0 inches
across our southern forecast area by this afternoon. Those numbers
are still well above normal for late December, so steady rains look
likely south of I-72 well into the afternoon. We are still looking
for a northward return of the band of rain toward evening, but only
slightly before 6 pm today. Overall forecast adjustments were mainly
to reduce PoPs in the northern half of the forecast area, while the
southern counties remained in categorical PoPs all day. Winds will
remain gusty from the northeast at 15 to 30 mph, as temperatures
remain relatively steady in the upper 30s to upper 40s through the
day.
.LONG TERM...(Tonight through Saturday)
ISSUED AT 351 AM CST SUN DEC 27 2015
00Z forecast models have trended back south with colder air and
increasing freezing rain threat into northern CWA later Sunday night
through Monday morning. Will be expanding the winter storm watch to
include Fulton, Peoria and Marshall counties from late Sunday
night until 3 pm Monday afternoon for ice accumulations up to a
quarter inch. Will continue Knox and Stark counties in the winter
storm watch as well where the highest amounts of ice around a
quarter inch are likely. Meanwhile the flood watch will continue
through Monday for areas along and south of I-72. Flooding already
widespread over parts of areas south of I-72 to north of I-70
especially in Shelby, Christian and Moultrie counties where as
much as 3-5 inches of rain has fallen in less than 24 hours since
Saturday morning. An additional 2-3 inches of rain with locally
higher amounts is expected over areas from I-72 south through
Monday.
Strong 544 dm 500 mb low in northern Mexico just south of AZ will
eject ne into eastern IA by midnight Monday night, and pass ne of MI
by Tue afternoon. Water Vapor loop shows a tropical plume of deep
moisture streaming into IL from the western Gulf and southern
Mexico. Precipitable water values were 1.3 inches at ILX 00Z
sounding early Sat evening and projected to peak at 1.4-1.6 inches
in southern CWA early this morning and then gradually lower
especially northern half of CWA this afternoon and evening.
Precipitable Water values rise back up to between 1-1.5 inches on
Monday. So showers and a few thunderstorms to be more prominent over
SE IL tonight, and shifting northward toward I-72 Monday morning
along with heavy rain threat as 2nd surge of moisture/lift moves
into IL. Meanwhile northern CWA should dry out for a time this
afternoon and early evening, before moisture lifts back northward
later this evening and overnight. Surface temps will get to near or
just below freezing along and north of a Rushville to Bloomington
line overnight into Monday morning where freezing rain appears more
likely with a tenth to quarter inch of ice along with some sleet.
Have highest amounts of ice nw of Peoria and expanded winter storm
watch as stated above. Surface temps should elevate into mid to
upper 30s by Monday afternoon with freezing rain turning back to
rain. Very windy conditions develop later Sunday night into Monday
with ENE winds 25-35 mph and peak wind gusts of 40-50 mph, so a
wind advisory will likely be needed then as event draws closer.
These strong winds with ice accumulations up to a quarter inch
especially north of Peoria Monday morning could cause additional
problems.
Precipitation will diminish from SW to ne during Monday night and
could change to some light snow showers nw half of CWA before ending
but little if any accumulations expected.
A northern stream weather system approaching the Pacific Northwest
will track into the Midwest by Wed morning and bring small chances
of light rain/snow showers to central IL on Wed. Southeast IL looks
drier now on Wed and wx system shifts ne of central IL Wed night.
Highs Wed to range from 30-35F nw of the IL river to 40-45F from I-
70 southeast.
Strong upper level trof dominates the northeast half of the country
during 2nd half of the week, while large Canadian high pressure
settling into the Rockies and high plains will bring an extended
period of below normal temperatures to IL for a change. The coldest
air will be over area on Thu/Fri with highs staying below freezing
all but far southeast IL. Have partly cloudy skies Thu/Fri (more
clouds in ne CWA). Highs will only modify slightly New Years weekend
into the low to mid 30s despite more sunshine. CPC`s 6-10 day
outlook for Jan 1-5th has great than normal chances of below normal
precipitation and temperatures.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
ISSUED AT 519 PM CST SUN DEC 27 2015
One more storm to go through over the next 24 hours with
additional rainfall and some freezing rain potential, especially
for PIA. The main impact with this storm not only will be with
the wintry precip across the north, but with strong easterly
winds tonight and especially on Monday as the storm moves towards
our area. Wind gusts of 40 to 45 kts possible on Monday out of
the east before winds slowly diminish after 21z as the storm
shifts off to our northwest by evening. The dry easterly flow
has eroded some of the lower clouds over the forecast area and
that should hold for several hours this evening at CMI, but
it appears as the rain moves from south to north this evening,
the low levels will gradually moisten and all areas should be
IFR to LIFR after 06z and continue thru the remainder of the
forecast period.
&&
.ILX Watches/Warnings/Advisories...
Flash Flood Watch through Monday afternoon for ILZ044>046-049-
050-052>057-061>063-066>068-071>073.
Wind Advisory from midnight tonight to 6 PM CST Monday for
ILZ027>031-036>038-040>057-061.
Winter Storm Warning from 3 AM to 3 PM CST Monday for ILZ027>031.
Flash Flood Watch through Monday evening for ILZ051.
Freezing Rain Advisory from midnight tonight to noon CST Monday
for ILZ036>038.
&&
$$
UPDATE...Geelhart
SHORT TERM...Shimon
LONG TERM...07
AVIATION...Smith
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
314 PM CST SAT DEC 26 2015
.UPDATE...
1108 AM CST
TSRA COVERAGE SEEMS TO BE ON A DOWNWARD TREND LATE THIS MORNING
AFTER A LITTLE MORE ACTIVITY SOUTH AND WEST THAN MIGHT HAVE BEEN
EXPECTED EARLIER TODAY. FOCUS FOR ADDITIONAL TSRA WILL SHIFT
WELL SOUTH OF THE CHICAGO METRO AREA MAINLY TO PORTIONS OF NW
INDIANA ALONG WITH THE ANTICIPATED AXIS OF HEAVIER RAINFALL. MAY
EVEN BE ABLE TO LOWER POPS IN NORTHERN PORTIONS OF THE AREA TOWARD
ROCKFORD AND THE WI LINE THIS AFTERNOON...OR CARRY JUST A MENTION
OF DRIZZLE. EVEN IN THE CHICAGO METRO AREA...DRIZZLE MIGHT BE THE
MAIN WEATHER TYPE THIS AFTERNOON AS THE LATEST AMDAR SOUNDINGS OUT
OF MDW ARE SHOWING JUST A RELATIVELY SHALLOW SATURATED LAYER TO
ABOUT 850 MB WITH DRY AIR ABOVE THAT. THIS ALSO CORRESPONDS TO
WHAT THE RAP IS SHOWING...WITH AN INCREASINGLY SHALLOW SATURATED
LAYER AS THE AFTERNOON PROGRESSES.
WINDS WILL RELAX THIS AFTERNOON AND TONIGHT BEFORE PICKING UP
CONSIDERABLY AGAIN TOMORROW MORNING.
LENNING
&&
.SHORT TERM...
411 AM CST
THROUGH TONIGHT...
FOCUS IS ON MODERATE TO LOCALLY HEAVY RAINFALL LATE THIS AFTERNOON
THROUGH TONIGHT.
DEEP UPPER LEVEL LOW PRESSURE CONTINUES TO STRENGTHEN OVER THE
DESTER SOUTHWEST...WITH STRONG AND UNSEASONABLY MOIST/WARM
ADVECTION OCCURRING OUT AHEAD OF THE LOW. SEVERAL COMPLEXES OF
THUNDERSTORMS ARE ONGOING IN THE WARM ADVECTIVE REGIME NORTH OF A
WARM FRONTAL BOUNDARY DRAPED FROM THE ARKLATEX REGION THEN
NORTHEAST INTO THE TENNESSEE VALLEY IN AN AREA OF ELEVATED MID
LEVEL LAPSE RATES. AN ADDITIONAL AREA OF PRECIPITATION IS
OCCURRING NORTH OF AN INVERTED SURFACE TROUGH.
THIS WARM/MOIST BOUNDARY CONTINUES TO ADVECT NORTHWARD THIS
MORNING WITH A PLUME OF NEAR RECORD PRECIPITABLE WATER VALUES.
WITH COOL NORTHEAST WINDS IN PLACE AHEAD ANCHORING THE LOW LEVEL
FRONTAL BOUNDARY TO OUR SOUTH WILL CREATE A RECIPE FOR LOW CLOUDS
TO OVERSPREAD THE AREA THIS MORNING...AS FORECAST SOUNDINGS
DEPICT RAPID SATURATION OF THE LOWER LEVELS WHICH HAS BEEN
OCCURRING DOWNSTATE. AS CLOUDS LOWER...EXPECT SOME FOG TO DEVELOP
AS WELL.
THE INVERTED TROUGH AXIS SHIFTS AND IS POINTED AT OUR AREA AROUND
MIDDAY. AS THIS OCCURS IN CONJUNCTION WITH ISENTROPIC
ASCENT...EXPECT AN INCREASE IN INITIALLY LIGHTER RAIN SHOWERS THIS
MORNING DUE TO LACK OF DEEPER SATURATION...THEN AS FORCING
INCREASES AHEAD OF A NORTHERN STREAM SHORTWAVE...STRENGTHENING
UPPER LEVEL JET MAXIMUM TO OUR NORTHWEST...AND A STRONG LOW TO MID
LEVEL FRONTOGENESIS OCCURRING DUE TO THE AIRMASS CLASH...EXPECT
SHOWERS TO BLOSSOM THIS AFTERNOON AND EVENING. PRECIPITATION MAY
DWINDLE TO LIGHTER RAIN/DRIZZLE FARTHER NORTH...BUT THERE ARE
ADDITIONAL WAVES THAT WILL RIDE ALONG THE LOW AND ELEVATED
BAROCLINIC ZONES TO KEEP A MENTION OF RAIN GOING AREA-WIDE TONIGHT.
THE FRONT LOOKS TO BE MOST ACTIVE ALONG OUR SOUTHERN COUNTIES
WHERE EXTREME FRONTOGENESIS COMBINED WITH THE RECORD PWATS WILL
LEAD TO PERIODS OF MODERATE TO HEAVY RAINFALL. THUNDER IS
CERTAINLY POSSIBLE EVEN AS FAR NORTH AS CHICAGO OR LAKE MICHIGAN
AS THE PLUME OF ELEVATED LAPSE RATES SPREADS OVERHEAD...BUT MORE
LIKELY FARTHER SOUTH CLOSER TO THE STRONGER COMBINED FORCING.
THERE LOOKS TO BE A VERY TIGHT GRADIENT IN THE HEAVY PRECIP AXIS.
HAVE ELECTED TO ISSUE A FLOOD WATCH SIMILAR TO OUR NEIGHBORS DUE
TO THIS POTENTIAL GIVEN THE CONVECTIVE ELEMENTS PRESENT. THERE IS
STILL WITH SOME UNCERTAINTY AS TO IF THIS WILL REMAIN SOUTH OF THE
AREA AS SUGGESTED BY SOME HI-RES GUIDANCE MEMBERS. HAVE CARRIED
THIS WATCH OUT THROUGH THE SECOND EVENT (LONG TERM)...THOUGH THERE
WILL BE A GAP ON SUNDAY. MORE ON THIS IN THE HYDROLOGY SECTION
FORTHCOMING.
KMD
&&
.LONG TERM...
SUNDAY NIGHT THROUGH SATURDAY...
314 PM...FORECAST FOCUS AND CHALLENGE REMAINS FREEZING RAIN AND
ICE ACCUMULATIONS MONDAY ALONG WITH VERY STRONG WINDS AND LAKE
SHORE FLOODING POTENTIAL.
STRONG LOW PRESSURE OVER THE ARKLATEX SUNDAY EVENING WILL MOVE NORTH
TO NORTHWEST IL OR NORTHEAST IA MONDAY NIGHT. GUIDANCE IS SLOWLY
CONVERGING ON THIS TRACK THOUGH SPEED OF THE LOW HAS SLOWED JUST A
BIT...WHICH WILL DELAY THE ONSET OF PRECIP UNTIL AFTER MIDNIGHT
SUNDAY NIGHT/EARLY MONDAY MORNING.
TEMPERATURES WILL START IN THE MID 30S SUNDAY EVENING AND SLOWLY
DROP INTO THE UPPER 20S NORTHWEST TO NEAR FREEZING FROM THE CHICAGO
LAKEFRONT INTO THE SOUTHERN CWA. AS PRECIP BEGINS TO FALL EARLY
MONDAY MORNING...EXPECT A SHORT PERIOD OF MAINLY SLEET...POSSIBLY
MIXED WITH SOME SNOW...BEFORE CHANGING TO MAINLY RAIN/FREEZING RAIN.
TEMPS WILL SLOWLY RISE ABOVE FREEZING FROM SOUTH TO NORTH MONDAY...
TRANSITIONING PRECIP OVER TO JUST RAIN AND HAVE SPED UP THIS CHANGE
OVER TO RAIN JUST A BIT IN THE GRIDS.
THE MAIN QUESTION IS HOW MUCH QPF WILL BE FALLING WHILE TEMPS ARE
STILL AT OR BELOW FREEZING AND CAN THE STRONG EASTERLY WINDS KEEP
ENOUGH COLDER/DRIER AIR ADVECTING IN UNDER THE FALLING PRECIP TO
KEEP IT COLD ENOUGH FOR SIGNIFICANT ICE ACCUMULATIONS. ITS GOING TO
BE A BATTLE BETWEEN THE WARMER AIR SPREADING NORTH ALONG WITH WARMER
RAIN FALLING VS THE COLDER AIR ADVECTING IN. IN ADDITION...TEMPS
ALONG THE LAKE MICHIGAN SHORE AND SOME DISTANCE INLAND...MAY REMAIN
AT OR ABOVE FREEZING. HAVE MAINTAINED ICE AMOUNTS MAINLY IN THE 0.1
TO 0.2 INCH RANGE. THERE IS SOME POTENTIAL FOR HIGHER AMOUNTS MAINLY
ACROSS FAR NORTHERN IL AND NORTHWEST IL. WITH THESE AMOUNTS...AND
GIVEN THE UNCERTAINTY OF HOW LONG PRECIP CAN REMAIN FREEZING
RAIN...HAVE OPTED TO ISSUE A WINTER STORM WATCH FOR PART OF THE
NORTHERN CWA. AN ADVISORY WILL LIKELY BE NEEDED SOUTH OF THE WATCH
AREA AS THE EVENT NEARS.
AS THE PRECIPITATION CHANGES OVER TO RAIN...THERE COULD BE ANOTHER
PERIOD OF MODERATE RAINFALL. TOTAL QPF FOR THIS EVENT FROM EARLY
MONDAY MORNING THROUGH EARLY TUESDAY MORNING IS LIKELY TO BE IN THE
1 TO 1.5 INCH RANGE...THUS THIS COULD CAUSE ADDITIONAL RISES ON
ALREADY HIGH/ELEVATED RIVER LEVELS.
AS THIS LOW APPROACHES SUNDAY NIGHT INTO MONDAY...THE GRADIENT WILL
RAPIDLY TIGHTEN WITH VERY STRONG EASTERLY WINDS DEVELOPING.
CURRENTLY HAVE WIND GUSTS 40-45 MPH MONDAY BUT ITS POSSIBLE WINDS
GUSTS MAY BE AS HIGH AS 50 TO 55 MPH...ESPECIALLY ACROSS NORTHERN IL
AND ALONG THE LAKE FRONT. NO HEADLINES FOR THESE WINDS YET EITHER...
BUT WIND ADVISORY CRITERIA IS CERTAINLY POSSIBLE. THIS LOW WILL
BEGIN TO WEAKEN MONDAY NIGHT AS IT LIFTS NORTH OF THE CWA...THUS
WINDS ARE EXPECTED TO QUICKLY DIMINISH MONDAY EVENING.
THESE STRONG EASTERLY WINDS WILL PILE UP THE WAVES ALONG THE IL LAKE
MICHIGAN SHORE AND ITS POSSIBLE WAVES MAY REACH 14 TO 18 FEET...
ESPECIALLY NORTH OF NORTHERLY ISLAND AND WILL BE ISSUING A LAKE
SHORE FLOOD WATCH FOR COOK AND LAKE COUNTIES IN IL FROM MONDAY
MORNING THROUGH MONDAY EVENING.
A WEAK SYSTEM WILL MOVE ACROSS THE UPPER MIDWEST/GREAT LAKES REGION
WEDNESDAY INTO WEDNESDAY NIGHT WITH A PERIOD OF LIGHT SNOW POSSIBLE
ACROSS PARTS OF THE AREA...MAYBE MIXED WITH A LITTLE LIGHT RAIN.
COLDER AIR THEN SPREADS ACROSS THE REGION THURSDAY AND FRIDAY. CMS
&&
.HYDROLOGY...
RAIN DEVELOPING ALONG A STATIONARY FRONT DURING THE DAY
TODAY...AND POSSIBLY HEAVY AT TIMES LATE THIS AFTERNOON TONIGHT...IS
LIKELY TO PERSIST THROUGH EARLY SUNDAY MORNING. THUNDERSTORMS
ALSO ARE POSSIBLE ACROSS SOUTHERN PORTIONS OF THE AREA MAINLY
SOUTH OF THE KANKAKEE RIVER...WHERE WIDESPREAD 1.5 TO 2 INCH
RAINFALL AMOUNTS ARE MOST LIKELY. LOCALIZED AMOUNTS IN EXCESS OF 3
INCHES REMAIN POSSIBLE...THOUGH AT THIS TIME THIS MAY OCCUR JUST
SOUTH OF THE LOCAL AREA. REGARDLESS...THESE RAINFALL AMOUNTS MAY
RESULT IN SIGNIFICANT RISES AND POSSIBLE FLOODING ALONG AREA
RIVERS AND STREAMS...INCLUDING THE IROQUOIS AND KANKAKEE RIVERS AS
WELL AS SUGAR CREEK. IN ADDITION...THE HEAVY RAIN WILL LIKELY
RESULT IN SOME PONDING OF WATER IN LOW LYING AND POOR DRAINAGE
AREAS. SEE THE CURRENT FFALOT FOR MORE DETAILS. THIS APPEARS TO BE
MORE OF A FLOODING SITUATION THAN A TRUE FLASH FLOOD
SITUATION...BUT GIVEN THE CONVECTIVE ELEMENT TO THE PRECIPITATION
AND THE EFFICIENCY OF THE PRECIPITATION EXPECTED TONIGHT AND
SATURATED GROUND...FLOODING COULD OCCUR QUICKLY FOR AREAS STUCK
UNDER HEAVY RAINFALL. THE FLOOD WATCH FOR OUR SOUTHERN COUNTIES WILL
ALSO ACCOUNT FOR ANOTHER 1-1.5 INCHES OF RAINFALL EXPECTED ON
MONDAY.
KMD
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* -RA/SHRA TRANSITIONING OVER TO DRIZZLE FOR THE REMAINDER OF THE
AFTERNOON THROUGH LATE TONIGHT...THOUGH A FEW LINGERING RAIN
SHOWERS WILL BE POSSIBLE THROUGH AROUND SUNSET. ANOTHER PERIOD
OF -RA LATE TONIGHT.
* IFR CIGS LIKELY THROUGH EARLY EVENING...THEN LIFR CIGS LIKELY
FOR THE LATE EVENING HOURS...BUT IMPROVING TO MVFR DURG THE LATE
NIGHT HOURS.
* EAST WINDS REMAIN ARND 5 TO 10 KT THROUGH LATE AFTERNOON
BACKING NNELY THIS EVENING. WINDS STRENGTHENING AND BECOMING
GUSTY TO ARND 25KT LATE TONIGHT AND TOMORROW.
KREIN
//DISCUSSION...UPDATED 18Z...
A MID LEVEL IMPULSE TRACKING ACROSS THE REGION HAS BROUGHT AN AREA
OF RAIN WITH MVFR CIGS/VIS AND OCNL IFR VIS IN HEAVIER SHOWERS.
SOME ISOLD EMBEDDED TS HAS BEEN OBSERVED WITHIN THE RAIN
AREA...BUT ANY TS HAVE REMAINED SOUTH AND EAST OF THE TERMINALS.
TS POTENTIAL SHOULD END BY 19-20Z AS THE IMPULSE MOVES OFF TO THE
NORTHEAST. MID LEVEL DRY AIR WILL OVERSPREAD THE REGION BEHIND THE
EXITING MID LEVEL IMPULSE...AND RAIN SHOULD TRANSITION OVER TO
DRIZZLE. WITH THE LOWER LEVELS REMAINING VERY MOIST...EXPECT THAT
CIGS/VIS SHOULD LOWER TO PREVAILING IFR BY SUNSET...WITH THE
POTENTIAL FOR LIFR CIGS OVERNIGHT. A MODEST PRESSURE GRADIENT
SHOULD KEEP NNELY WINDS OF 5-10KT THROUGH THE LATE NIGHT
HOURS...SO DO NOT EXPECT DENSE FOG TO FORM. DURG THE EARLY MORNING
HOURS...AS DEEPENING LOW PRESSURE LIFTS NORTHEAST OUT OF ERN
OKLAHOMA THROUGH MISSOURI TOMORROW...EXPECT A STRENGTHENING NNELY
PRESSURE GRADIENT...WITH WINDS GUSTING TO 25KT BY ARND 12Z
TOMORROW MORNING AND SUSTAINED WINDS AND GUSTS LIKELY INCREASING
THROUGH THE DAY TOMORROW AS THE LOW MOVES TO SERN IOWA LATE
TOMORROW AFTERNOON.
KREIN
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* MEDIUM CONFIDENCE IN PRECIP/VISBY TRENDS.
* HIGH CONFIDENCE IN IFR/LIFR CIGS...MEDIUM CONFIDENCE IN TIMING
OF IFR/LIFR CIGS.
* MEDIUM-HIGH CONFIDENCE IN WIND TRENDS.
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT...WINTRY MIX POSSIBLE LATE. MVFR CIGS PSBL.
MONDAY...WINTRY MIX TURNING TO RAIN. MVFR CIGS AND VSBYS.
TUESDAY...MVFR CIGS. CHANCE OF -SN/RA IN THE MORNING.
WEDNESDAY...MVFR CIGS. CHANCE OF -SN.
THURSDAY...MVFR CIGS.
FRIDAY...DRY. VFR.
KMD
&&
.MARINE...
213 PM CST
QUITE A FEW QUESTIONS FOR THE MARINE FORECAST OVER THE NEXT TWO OR
THREE DAYS. THE MAIN EVENT OF CONCERN WILL BE ON MONDAY WITH A PROLONGED
PERIOD OF NORTHEAST GALES...WITH POSSIBLE STORM FORCE GUSTS ACROSS THE
SOUTH HALF. AT THE PRESENT TIME A SMALL CRAFT ADVISORY IN EFFECT FOR
THE IL WATERS WILL BE EXTENDED THROUGH TOMORROW NIGHT...UP UNTIL THE
TIME OF THE GALES ON MONDAY. AN ADDITIONAL ADVISORY FOR THE INDIANA
WATERS WILL GO INTO EFFECT FOR THE SAME PERIOD STARTING THIS
EVENING. WINDS AND WAVES WILL BOTH BE A CONCERN. THERE ALSO IS A
CONCERN THAT LOW END GALES MAY DEVELOP FOR A TIME TOMORROW
AFTERNOON...BUT THIS WOULD BE MAINLY IN THE GUSTS AND NOWHERE
CLOSE TO THE STRENGTH OF WINDS ON MONDAY.
FOR MONDAY THERE WAS QUITE A BIT OF THOUGHT AND DISCUSSION ABOUT
GOING WITH A STORM WATCH ACROSS THE SOUTH HALF...BUT FOR NOW WILL
GO WITH A WATCH FOR HIGH END GALES AND JUST MENTION THE
POSSIBILITY OF OCCASIONAL STORM FORCE GUSTS ACROSS THE SOUTH HALF.
THIS MAY NEED TO BE UPGRADED AS THE EVENT APPROACHES.
AFTER THE EVENT TO START THE WEEK...WINDS DIMINISH AND TURN WEST
ON TUESDAY THEN GENERALLY MAINTAIN A WESTERLY COMPONENT FOR THE
REMAINDER OF THE WEEK.
LENNING
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLASH FLOOD WATCH...ILZ033-ILZ039 UNTIL 6 PM MONDAY.
LAKESHORE FLOOD WATCH...ILZ006-ILZ014...9 AM MONDAY TO 9 PM
MONDAY.
IN...FLASH FLOOD WATCH...INZ010-INZ011-INZ019 UNTIL 6 PM MONDAY.
LM...GALE WATCH...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-
LMZ779...3 AM MONDAY TO 3 AM TUESDAY.
SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 3 AM MONDAY.
SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 3 AM MONDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
218 PM CST SAT DEC 26 2015
.UPDATE...
1108 AM CST
TSRA COVERAGE SEEMS TO BE ON A DOWNWARD TREND LATE THIS MORNING
AFTER A LITTLE MORE ACTIVITY SOUTH AND WEST THAN MIGHT HAVE BEEN
EXPECTED EARLIER TODAY. FOCUS FOR ADDITIONAL TSRA WILL SHIFT
WELL SOUTH OF THE CHICAGO METRO AREA MAINLY TO PORTIONS OF NW
INDIANA ALONG WITH THE ANTICIPATED AXIS OF HEAVIER RAINFALL. MAY
EVEN BE ABLE TO LOWER POPS IN NORTHERN PORTIONS OF THE AREA TOWARD
ROCKFORD AND THE WI LINE THIS AFTERNOON...OR CARRY JUST A MENTION
OF DRIZZLE. EVEN IN THE CHICAGO METRO AREA...DRIZZLE MIGHT BE THE
MAIN WEATHER TYPE THIS AFTERNOON AS THE LATEST AMDAR SOUNDINGS OUT
OF MDW ARE SHOWING JUST A RELATIVELY SHALLOW SATURATED LAYER TO
ABOUT 850 MB WITH DRY AIR ABOVE THAT. THIS ALSO CORRESPONDS TO
WHAT THE RAP IS SHOWING...WITH AN INCREASINGLY SHALLOW SATURATED
LAYER AS THE AFTERNOON PROGRESSES.
WINDS WILL RELAX THIS AFTERNOON AND TONIGHT BEFORE PICKING UP
CONSIDERABLY AGAIN TOMORROW MORNING.
LENNING
&&
.SHORT TERM...
411 AM CST
THROUGH TONIGHT...
FOCUS IS ON MODERATE TO LOCALLY HEAVY RAINFALL LATE THIS AFTERNOON
THROUGH TONIGHT.
DEEP UPPER LEVEL LOW PRESSURE CONTINUES TO STRENGTHEN OVER THE
DESTER SOUTHWEST...WITH STRONG AND UNSEASONABLY MOIST/WARM
ADVECTION OCCURRING OUT AHEAD OF THE LOW. SEVERAL COMPLEXES OF
THUNDERSTORMS ARE ONGOING IN THE WARM ADVECTIVE REGIME NORTH OF A
WARM FRONTAL BOUNDARY DRAPED FROM THE ARKLATEX REGION THEN
NORTHEAST INTO THE TENNESSEE VALLEY IN AN AREA OF ELEVATED MID
LEVEL LAPSE RATES. AN ADDITIONAL AREA OF PRECIPITATION IS
OCCURRING NORTH OF AN INVERTED SURFACE TROUGH.
THIS WARM/MOIST BOUNDARY CONTINUES TO ADVECT NORTHWARD THIS
MORNING WITH A PLUME OF NEAR RECORD PRECIPITABLE WATER VALUES.
WITH COOL NORTHEAST WINDS IN PLACE AHEAD ANCHORING THE LOW LEVEL
FRONTAL BOUNDARY TO OUR SOUTH WILL CREATE A RECIPE FOR LOW CLOUDS
TO OVERSPREAD THE AREA THIS MORNING...AS FORECAST SOUNDINGS
DEPICT RAPID SATURATION OF THE LOWER LEVELS WHICH HAS BEEN
OCCURRING DOWNSTATE. AS CLOUDS LOWER...EXPECT SOME FOG TO DEVELOP
AS WELL.
THE INVERTED TROUGH AXIS SHIFTS AND IS POINTED AT OUR AREA AROUND
MIDDAY. AS THIS OCCURS IN CONJUNCTION WITH ISENTROPIC
ASCENT...EXPECT AN INCREASE IN INITIALLY LIGHTER RAIN SHOWERS THIS
MORNING DUE TO LACK OF DEEPER SATURATION...THEN AS FORCING
INCREASES AHEAD OF A NORTHERN STREAM SHORTWAVE...STRENGTHENING
UPPER LEVEL JET MAXIMUM TO OUR NORTHWEST...AND A STRONG LOW TO MID
LEVEL FRONTOGENESIS OCCURRING DUE TO THE AIRMASS CLASH...EXPECT
SHOWERS TO BLOSSOM THIS AFTERNOON AND EVENING. PRECIPITATION MAY
DWINDLE TO LIGHTER RAIN/DRIZZLE FARTHER NORTH...BUT THERE ARE
ADDITIONAL WAVES THAT WILL RIDE ALONG THE LOW AND ELEVATED
BAROCLINIC ZONES TO KEEP A MENTION OF RAIN GOING AREA-WIDE TONIGHT.
THE FRONT LOOKS TO BE MOST ACTIVE ALONG OUR SOUTHERN COUNTIES
WHERE EXTREME FRONTOGENESIS COMBINED WITH THE RECORD PWATS WILL
LEAD TO PERIODS OF MODERATE TO HEAVY RAINFALL. THUNDER IS
CERTAINLY POSSIBLE EVEN AS FAR NORTH AS CHICAGO OR LAKE MICHIGAN
AS THE PLUME OF ELEVATED LAPSE RATES SPREADS OVERHEAD...BUT MORE
LIKELY FARTHER SOUTH CLOSER TO THE STRONGER COMBINED FORCING.
THERE LOOKS TO BE A VERY TIGHT GRADIENT IN THE HEAVY PRECIP AXIS.
HAVE ELECTED TO ISSUE A FLOOD WATCH SIMILAR TO OUR NEIGHBORS DUE
TO THIS POTENTIAL GIVEN THE CONVECTIVE ELEMENTS PRESENT. THERE IS
STILL WITH SOME UNCERTAINTY AS TO IF THIS WILL REMAIN SOUTH OF THE
AREA AS SUGGESTED BY SOME HI-RES GUIDANCE MEMBERS. HAVE CARRIED
THIS WATCH OUT THROUGH THE SECOND EVENT (LONG TERM)...THOUGH THERE
WILL BE A GAP ON SUNDAY. MORE ON THIS IN THE HYDROLOGY SECTION
FORTHCOMING.
KMD
&&
.LONG TERM...
333 AM CST
SUNDAY THROUGH FRIDAY...
THE FOCUS ON THE LONGER RANGE FORECAST IS CERTAINLY WITH THE SUNDAY
NIGHT THROUGH MONDAY NIGHT PRECIPITATION EVENT...WHICH IS TRENDING
MORE TOWARD A RAIN/FREEZING RAIN EVENT. THIS STILL LOOKS TO BE LARGE
CONCERNS OF ICING FROM FREEZING RAIN FOR AT LEAST A PORTION OF THE
AREA...ESPECIALLY AREAS ALONG AND NORTH OF I-80. THERE ALSO IS
CONCERNS THAT THE AMOUNT OF RAIN /WHETHER INITIALLY FREEZING OR NOT/
COULD CAUSE LOCALIZED FLOODING ISSUES AS MONDAY PROGRESSES AND
CERTAINLY SOME QUICK RIVER RISES. IT IS A BIT CLEARER PICTURE THAT
THE POTENTIAL FOR SNOW IS LESS LIKELY THROUGH MONDAY NIGHT. HAVE
ADDED A LITTLE MORE DETAIL IN THE FORECAST...BUT OVERALL KEPT SOME
RANGE OF UNCERTAINTY DUE TO THE SPECIFIC SURFACE TEMPERATURE
FORECASTS AS WELL AS THE LARGER SCALE EXACT TRACK OF THE SYSTEM.
LAST EVENINGS RAOBS INDICATED A STRONG JET STREAM MAXIMUM OF AROUND
150 KT DIGGING SOUTH ACROSS THE WESTERN U.S. WHICH WILL CUT OFF A
CLOSED LOW ACROSS THE DESERT SOUTHWEST/MEXICO BORDER BY TONIGHT.
THIS WILL EVOLVE NORTHEAST IN RESPONSE TO ANOTHER JET MAXIMUM
DIGGING UPSTREAM. A CUTOFF FEATURE SUCH AS THIS LOW AND BEING
FAIRLY FAR SOUTH IN LATITUDE TENDS TO END UP BEING SLOWER THAN A
MEAN MODEL SOLUTION AND WE HAVE SEEN THAT OVER THE PAST COUPLE
MONTHS WITH SYSTEMS LOCATED EVEN FURTHER NORTH. SUCH A SLOWER
EVOLUTION WOULD RESULT IN A FURTHER WEST TRACK AS THE SYSTEM LIFTS
NORTHEAST WHICH IS ADVERTISED BY THE PREFERRED EC...NAM...AND
SREF MORE SO THAN THE GFS...ITS ENSEMBLE...AND THE GEM. THE
OVERALL TREND IN A MEAN OF ALL THESE GUIDANCE HAS ALSO SHIFTED
SLIGHTLY SLOWER AND FURTHER WEST WITH THIS SYSTEM...FURTHER
SUPPORTING LEANING THIS ROUTE. IN ADDITION...THE STRONG CANADIAN
HIGH PRESSURE OVER THE NORTHERN PLAINS THAT COULD OFFER SOME
BLOCKING AND SUPPORT A FURTHER EAST TRACK IN THE LOW IS TRENDING
SLIGHTLY FURTHER NORTH...AGAIN FAVORING LEANING WEST.
FOR SUNDAY...LOW-LEVEL COLD ADVECTION ON GUSTY NORTHERLY WINDS
WILL BE UNDERCUTTING THE ELEVATED BAROCLINIC ZONE AND EXPECT
TEMPERATURES TO REMAIN IN THE 30S BUT FEELING EVEN COLDER. THERE
PROBABLY WILL BE LAKE EFFECT CLOUDS AND MAYBE EVEN SOME DRIZZLE
FROM THAT DURING THE MORNING INTO CHICAGO AND OTHER LAKE ADJACENT
AREAS. AS FOR THE PREVAILING RAIN IN THE SOUTHERN AND EASTERN
FORECAST AREA SUNDAY MORNING...THAT SHOULD EASE SOUTHEASTWARD IN
THE AFTERNOON AS FRONTOGENESIS TEMPORARILY WEAKENS.
THE WARM AND MOIST ADVECTION ALOFT GRADUALLY STRENGTHENS SUNDAY
EVENING IN RESPONSE TO THE UPPER LOW APPROACHING AND REALLY RAMPS UP
EITHER LATE THAT NIGHT OR MONDAY MORNING OVER THE AREA. THE NAM
IS THE SLOWEST ADVANCING ITS PRECIPITATION AND IF CORRECT WOULD
INDICATE NOT MUCH IN THE AREA PRIOR TO DAYBREAK MONDAY...BUT HAVE
LEANED A LITTLE QUICKER THAN ITS SOLUTION GIVEN THE STRENGTH OF
THE MOISTURE ADVECTION.
EASTERLY SURFACE WINDS WILL STRENGTHEN OVERNIGHT GIVEN THE
PRESSURE GRADIENT RAPIDLY TIGHTENING. THIS ALONG WITH CLOUDS
SHOULD KEEP TEMPERATURES FAIRLY STEADY...THOUGH AS MENTIONED IN
PRIOR AFD THAT AT PRECIP ONSET...WHETHER LATE SUNDAY NIGHT OR
MONDAY MORNING...MAY RESULT IN A COUPLE DEGREE TEMPERATURE DROP.
THIS COULD MEAN A WINDOW OF SOME SLEET BUT OVERALL NOT EXPECTING
THAT TO BE THE DOMINANT TYPE OF PRECIPITATION FOR ANY EXTENDED
PERIOD. WITH BIG TIME UPPER SUPPORT FOR LIFT...PRECIPITATION
SHOULD BE AT ITS MAXIMUM COVERAGE AND INTENSITY DURING THE DAY
MONDAY AND AT LEAST EARLY MONDAY EVENING...IF NOT MUCH OF IT.
MIXING RATIOS OF 6-8 G/KG SHOULD SUPPORT MODEST IF NOT TEMPORARILY
HEAVY RATES...AND OBVIOUSLY THATS WHERE CONCERNS ARE REALLY
HEIGHTENED WITH ANY FREEZING RAIN.
GIVEN THE QUICK UPTICK IN INTENSITY OF RAINFALL AND EASTERLY
SURFACE WINDS...HAVE CONTINUED TO KEEP TEMPERATURES SLOW TO WARM
DURING THE DAY. TEMPERATURES STILL SHOULD BE INCHING UP TO OR EVEN
ABOVE FREEZING FROM SOUTH TO NORTH ACROSS THE AREA...BUT THAT
LOOKS LIKE IT WILL LAG THE ONSET OF MODERATE PRECIPITATION AND
THUS CONTINUE WITH FORECAST ICE ACCUMULATION IN THE CWA...NAMELY
THE NORTHERN HALF AWAY FROM THE IMMEDIATE LAKE. FOR AREAS ADJACENT
TO LAKE MICHIGAN...INCLUDING DOWNTOWN CHICAGO...STIFF ONSHORE FLOW
GUSTING TO 40 MPH PLUS /ESPECIALLY NEAR THE LAKE SHORE/ SHOULD
KEEP TEMPERATURES JUST ABOVE FREEZING. TEMPERATURES DO NOT LOOK TO
BE SIGNIFICANTLY BELOW FREEZING WHERE THEY ARE SUB 32...WHICH IS
ONE THING THAT COULD HELP EASE IMPACTS. IF HOWEVER ICE ACCRETION
DOES BEGIN ON LIMBS OR POWER LINES AND OVER SEVERAL HOURS...THE
STRONG WINDS COULD ALLOW FOR HIGHER IMPACTS.
AGAIN IN SUMMARY...THINGS GOING FOR THIS EVENT ARE A STIFF EAST WIND
AND A WIDESPREAD PRECIPITATION SHIELD TO KEEP THE SURFACE
TEMPERATURES FROM WARMING RAPIDLY...OR AT LEAST MORE RAPIDLY THAN
EVEN THE WARMEST GUIDANCE...AND THUS ALLOW FOR WHAT APPEARS TO BE
SEVERAL HOUR DURATION OF FREEZING RAIN. MOST CONCERNED FOR NORTH
CENTRAL ILLINOIS...INCLUDING ROCKFORD...WHERE COLLABORATED ICE
FORECASTS WITH WPC AND ADJACENT WFOS IS PRESENTLY AT OR ABOVE 0.20
OF AN INCH.
TUESDAY STILL LOOKS TO OFFER SOME SNOW POSSIBILITY ON THE
BACKSIDE OF THE SYSTEM...THOUGH WITH IT FILLING AM NOT EXPECTING A
WELL- DEFINED DEFORMATION/WRAPAROUND AS FAR EAST AS THE CWA.
TEMPERATURES LOOK TO EASE DOWN THROUGH THE WEEK INTO UNFAMILIAR
TERRITORY OF BELOW NORMAL BY THE START TO 2016. THERE CONTINUES
TO BE A CHANCE OF SNOW ON WEDNESDAY BUT HAVE GONE WITH A WELL-
VERIFYING MODEL BLEND AT THIS TIME TO FOCUS ON THE PREVIOUS
SYSTEMS.
MTF
&&
.HYDROLOGY...
RAIN DEVELOPING ALONG A STATIONARY FRONT DURING THE DAY
TODAY...AND POSSIBLY HEAVY AT TIMES LATE THIS AFTERNOON TONIGHT...IS
LIKELY TO PERSIST THROUGH EARLY SUNDAY MORNING. THUNDERSTORMS
ALSO ARE POSSIBLE ACROSS SOUTHERN PORTIONS OF THE AREA MAINLY
SOUTH OF THE KANKAKEE RIVER...WHERE WIDESPREAD 1.5 TO 2 INCH
RAINFALL AMOUNTS ARE MOST LIKELY. LOCALIZED AMOUNTS IN EXCESS OF 3
INCHES REMAIN POSSIBLE...THOUGH AT THIS TIME THIS MAY OCCUR JUST
SOUTH OF THE LOCAL AREA. REGARDLESS...THESE RAINFALL AMOUNTS MAY
RESULT IN SIGNIFICANT RISES AND POSSIBLE FLOODING ALONG AREA
RIVERS AND STREAMS...INCLUDING THE IROQUOIS AND KANKAKEE RIVERS AS
WELL AS SUGAR CREEK. IN ADDITION...THE HEAVY RAIN WILL LIKELY
RESULT IN SOME PONDING OF WATER IN LOW LYING AND POOR DRAINAGE
AREAS. SEE THE CURRENT FFALOT FOR MORE DETAILS. THIS APPEARS TO BE
MORE OF A FLOODING SITUATION THAN A TRUE FLASH FLOOD
SITUATION...BUT GIVEN THE CONVECTIVE ELEMENT TO THE PRECIPITATION
AND THE EFFICIENCY OF THE PRECIPITATION EXPECTED TONIGHT AND
SATURATED GROUND...FLOODING COULD OCCUR QUICKLY FOR AREAS STUCK
UNDER HEAVY RAINFALL. THE FLOOD WATCH FOR OUR SOUTHERN COUNTIES WILL
ALSO ACCOUNT FOR ANOTHER 1-1.5 INCHES OF RAINFALL EXPECTED ON
MONDAY.
KMD
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* -RA/SHRA TRANSITIONING OVER TO DRIZZLE FOR THE REMAINDER OF THE
AFTERNOON THROUGH LATE TONIGHT...THOUGH A FEW LINGERING RAIN
SHOWERS WILL BE POSSIBLE THROUGH AROUND SUNSET. ANOTHER PERIOD
OF -RA LATE TONIGHT.
* IFR CIGS LIKELY THROUGH EARLY EVENING...THEN LIFR CIGS LIKELY
FOR THE LATE EVENING HOURS...BUT IMPROVING TO MVFR DURG THE LATE
NIGHT HOURS.
* EAST WINDS REMAIN ARND 5 TO 10 KT THROUGH LATE AFTERNOON
BACKING NNELY THIS EVENING. WINDS STRENGTHENING AND BECOMING
GUSTY TO ARND 25KT LATE TONIGHT AND TOMORROW.
KREIN
//DISCUSSION...UPDATED 18Z...
A MID LEVEL IMPULSE TRACKING ACROSS THE REGION HAS BROUGHT AN AREA
OF RAIN WITH MVFR CIGS/VIS AND OCNL IFR VIS IN HEAVIER SHOWERS.
SOME ISOLD EMBEDDED TS HAS BEEN OBSERVED WITHIN THE RAIN
AREA...BUT ANY TS HAVE REMAINED SOUTH AND EAST OF THE TERMINALS.
TS POTENTIAL SHOULD END BY 19-20Z AS THE IMPULSE MOVES OFF TO THE
NORTHEAST. MID LEVEL DRY AIR WILL OVERSPREAD THE REGION BEHIND THE
EXITING MID LEVEL IMPULSE...AND RAIN SHOULD TRANSITION OVER TO
DRIZZLE. WITH THE LOWER LEVELS REMAINING VERY MOIST...EXPECT THAT
CIGS/VIS SHOULD LOWER TO PREVAILING IFR BY SUNSET...WITH THE
POTENTIAL FOR LIFR CIGS OVERNIGHT. A MODEST PRESSURE GRADIENT
SHOULD KEEP NNELY WINDS OF 5-10KT THROUGH THE LATE NIGHT
HOURS...SO DO NOT EXPECT DENSE FOG TO FORM. DURG THE EARLY MORNING
HOURS...AS DEEPENING LOW PRESSURE LIFTS NORTHEAST OUT OF ERN
OKLAHOMA THROUGH MISSOURI TOMORROW...EXPECT A STRENGTHENING NNELY
PRESSURE GRADIENT...WITH WINDS GUSTING TO 25KT BY ARND 12Z
TOMORROW MORNING AND SUSTAINED WINDS AND GUSTS LIKELY INCREASING
THROUGH THE DAY TOMORROW AS THE LOW MOVES TO SERN IOWA LATE
TOMORROW AFTERNOON.
KREIN
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* MEDIUM CONFIDENCE IN PRECIP/VISBY TRENDS.
* HIGH CONFIDENCE IN IFR/LIFR CIGS...MEDIUM CONFIDENCE IN TIMING
OF IFR/LIFR CIGS.
* MEDIUM-HIGH CONFIDENCE IN WIND TRENDS.
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT...WINTRY MIX POSSIBLE LATE. MVFR CIGS PSBL.
MONDAY...WINTRY MIX TURNING TO RAIN. MVFR CIGS AND VSBYS.
TUESDAY...MVFR CIGS. CHANCE OF -SN/RA IN THE MORNING.
WEDNESDAY...MVFR CIGS. CHANCE OF -SN.
THURSDAY...MVFR CIGS.
FRIDAY...DRY. VFR.
KMD
&&
.MARINE...
213 PM CST
QUITE A FEW QUESTIONS FOR THE MARINE FORECAST OVER THE NEXT TWO OR
THREE DAYS. THE MAIN EVENT OF CONCERN WILL BE ON MONDAY WITH A PROLONGED
PERIOD OF NORTHEAST GALES...WITH POSSIBLE STORM FORCE GUSTS ACROSS THE
SOUTH HALF. AT THE PRESENT TIME A SMALL CRAFT ADVISORY IN EFFECT FOR
THE IL WATERS WILL BE EXTENDED THROUGH TOMORROW NIGHT...UP UNTIL THE
TIME OF THE GALES ON MONDAY. AN ADDITIONAL ADVISORY FOR THE INDIANA
WATERS WILL GO INTO EFFECT FOR THE SAME PERIOD STARTING THIS
EVENING. WINDS AND WAVES WILL BOTH BE A CONCERN. THERE ALSO IS A
CONCERN THAT LOW END GALES MAY DEVELOP FOR A TIME TOMORROW
AFTERNOON...BUT THIS WOULD BE MAINLY IN THE GUSTS AND NOWHERE
CLOSE TO THE STRENGTH OF WINDS ON MONDAY.
FOR MONDAY THERE WAS QUITE A BIT OF THOUGHT AND DISCUSSION ABOUT
GOING WITH A STORM WATCH ACROSS THE SOUTH HALF...BUT FOR NOW WILL
GO WITH A WATCH FOR HIGH END GALES AND JUST MENTION THE
POSSIBILITY OF OCCASIONAL STORM FORCE GUSTS ACROSS THE SOUTH HALF.
THIS MAY NEED TO BE UPGRADED AS THE EVENT APPROACHES.
AFTER THE EVENT TO START THE WEEK...WINDS DIMINISH AND TURN WEST
ON TUESDAY THEN GENERALLY MAINTAIN A WESTERLY COMPONENT FOR THE
REMAINDER OF THE WEEK.
LENNING
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLASH FLOOD WATCH...ILZ033-ILZ039...6 PM SATURDAY TO 6 PM MONDAY.
LAKESHORE FLOOD WATCH...ILZ006-ILZ014...9 AM MONDAY TO 9 PM
MONDAY.
IN...FLASH FLOOD WATCH...INZ010-INZ011-INZ019...6 PM SATURDAY TO 6 PM
MONDAY.
LM...GALE WATCH...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-
LMZ779...3 AM MONDAY TO 3 AM TUESDAY.
SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 3 AM MONDAY.
SMALL CRAFT ADVISORY...LMZ743-LMZ744-LMZ745...6 PM SATURDAY TO 3
AM MONDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
148 PM CST SAT DEC 26 2015
.UPDATE...
1108 AM CST
TSRA COVERAGE SEEMS TO BE ON A DOWNWARD TREND LATE THIS MORNING
AFTER A LITTLE MORE ACTIVITY SOUTH AND WEST THAN MIGHT HAVE BEEN
EXPECTED EARLIER TODAY. FOCUS FOR ADDITIONAL TSRA WILL SHIFT
WELL SOUTH OF THE CHICAGO METRO AREA MAINLY TO PORTIONS OF NW
INDIANA ALONG WITH THE ANTICIPATED AXIS OF HEAVIER RAINFALL. MAY
EVEN BE ABLE TO LOWER POPS IN NORTHERN PORTIONS OF THE AREA TOWARD
ROCKFORD AND THE WI LINE THIS AFTERNOON...OR CARRY JUST A MENTION
OF DRIZZLE. EVEN IN THE CHICAGO METRO AREA...DRIZZLE MIGHT BE THE
MAIN WEATHER TYPE THIS AFTERNOON AS THE LATEST AMDAR SOUNDINGS OUT
OF MDW ARE SHOWING JUST A RELATIVELY SHALLOW SATURATED LAYER TO
ABOUT 850 MB WITH DRY AIR ABOVE THAT. THIS ALSO CORRESPONDS TO
WHAT THE RAP IS SHOWING...WITH AN INCREASINGLY SHALLOW SATURATED
LAYER AS THE AFTERNOON PROGRESSES.
WINDS WILL RELAX THIS AFTERNOON AND TONIGHT BEFORE PICKING UP
CONSIDERABLY AGAIN TOMORROW MORNING.
LENNING
&&
.SHORT TERM...
411 AM CST
THROUGH TONIGHT...
FOCUS IS ON MODERATE TO LOCALLY HEAVY RAINFALL LATE THIS AFTERNOON
THROUGH TONIGHT.
DEEP UPPER LEVEL LOW PRESSURE CONTINUES TO STRENGTHEN OVER THE
DESTER SOUTHWEST...WITH STRONG AND UNSEASONABLY MOIST/WARM
ADVECTION OCCURRING OUT AHEAD OF THE LOW. SEVERAL COMPLEXES OF
THUNDERSTORMS ARE ONGOING IN THE WARM ADVECTIVE REGIME NORTH OF A
WARM FRONTAL BOUNDARY DRAPED FROM THE ARKLATEX REGION THEN
NORTHEAST INTO THE TENNESSEE VALLEY IN AN AREA OF ELEVATED MID
LEVEL LAPSE RATES. AN ADDITIONAL AREA OF PRECIPITATION IS
OCCURRING NORTH OF AN INVERTED SURFACE TROUGH.
THIS WARM/MOIST BOUNDARY CONTINUES TO ADVECT NORTHWARD THIS
MORNING WITH A PLUME OF NEAR RECORD PRECIPITABLE WATER VALUES.
WITH COOL NORTHEAST WINDS IN PLACE AHEAD ANCHORING THE LOW LEVEL
FRONTAL BOUNDARY TO OUR SOUTH WILL CREATE A RECIPE FOR LOW CLOUDS
TO OVERSPREAD THE AREA THIS MORNING...AS FORECAST SOUNDINGS
DEPICT RAPID SATURATION OF THE LOWER LEVELS WHICH HAS BEEN
OCCURRING DOWNSTATE. AS CLOUDS LOWER...EXPECT SOME FOG TO DEVELOP
AS WELL.
THE INVERTED TROUGH AXIS SHIFTS AND IS POINTED AT OUR AREA AROUND
MIDDAY. AS THIS OCCURS IN CONJUNCTION WITH ISENTROPIC
ASCENT...EXPECT AN INCREASE IN INITIALLY LIGHTER RAIN SHOWERS THIS
MORNING DUE TO LACK OF DEEPER SATURATION...THEN AS FORCING
INCREASES AHEAD OF A NORTHERN STREAM SHORTWAVE...STRENGTHENING
UPPER LEVEL JET MAXIMUM TO OUR NORTHWEST...AND A STRONG LOW TO MID
LEVEL FRONTOGENESIS OCCURRING DUE TO THE AIRMASS CLASH...EXPECT
SHOWERS TO BLOSSOM THIS AFTERNOON AND EVENING. PRECIPITATION MAY
DWINDLE TO LIGHTER RAIN/DRIZZLE FARTHER NORTH...BUT THERE ARE
ADDITIONAL WAVES THAT WILL RIDE ALONG THE LOW AND ELEVATED
BAROCLINIC ZONES TO KEEP A MENTION OF RAIN GOING AREA-WIDE TONIGHT.
THE FRONT LOOKS TO BE MOST ACTIVE ALONG OUR SOUTHERN COUNTIES
WHERE EXTREME FRONTOGENESIS COMBINED WITH THE RECORD PWATS WILL
LEAD TO PERIODS OF MODERATE TO HEAVY RAINFALL. THUNDER IS
CERTAINLY POSSIBLE EVEN AS FAR NORTH AS CHICAGO OR LAKE MICHIGAN
AS THE PLUME OF ELEVATED LAPSE RATES SPREADS OVERHEAD...BUT MORE
LIKELY FARTHER SOUTH CLOSER TO THE STRONGER COMBINED FORCING.
THERE LOOKS TO BE A VERY TIGHT GRADIENT IN THE HEAVY PRECIP AXIS.
HAVE ELECTED TO ISSUE A FLOOD WATCH SIMILAR TO OUR NEIGHBORS DUE
TO THIS POTENTIAL GIVEN THE CONVECTIVE ELEMENTS PRESENT. THERE IS
STILL WITH SOME UNCERTAINTY AS TO IF THIS WILL REMAIN SOUTH OF THE
AREA AS SUGGESTED BY SOME HI-RES GUIDANCE MEMBERS. HAVE CARRIED
THIS WATCH OUT THROUGH THE SECOND EVENT (LONG TERM)...THOUGH THERE
WILL BE A GAP ON SUNDAY. MORE ON THIS IN THE HYDROLOGY SECTION
FORTHCOMING.
KMD
&&
.LONG TERM...
333 AM CST
SUNDAY THROUGH FRIDAY...
THE FOCUS ON THE LONGER RANGE FORECAST IS CERTAINLY WITH THE SUNDAY
NIGHT THROUGH MONDAY NIGHT PRECIPITATION EVENT...WHICH IS TRENDING
MORE TOWARD A RAIN/FREEZING RAIN EVENT. THIS STILL LOOKS TO BE LARGE
CONCERNS OF ICING FROM FREEZING RAIN FOR AT LEAST A PORTION OF THE
AREA...ESPECIALLY AREAS ALONG AND NORTH OF I-80. THERE ALSO IS
CONCERNS THAT THE AMOUNT OF RAIN /WHETHER INITIALLY FREEZING OR NOT/
COULD CAUSE LOCALIZED FLOODING ISSUES AS MONDAY PROGRESSES AND
CERTAINLY SOME QUICK RIVER RISES. IT IS A BIT CLEARER PICTURE THAT
THE POTENTIAL FOR SNOW IS LESS LIKELY THROUGH MONDAY NIGHT. HAVE
ADDED A LITTLE MORE DETAIL IN THE FORECAST...BUT OVERALL KEPT SOME
RANGE OF UNCERTAINTY DUE TO THE SPECIFIC SURFACE TEMPERATURE
FORECASTS AS WELL AS THE LARGER SCALE EXACT TRACK OF THE SYSTEM.
LAST EVENINGS RAOBS INDICATED A STRONG JET STREAM MAXIMUM OF AROUND
150 KT DIGGING SOUTH ACROSS THE WESTERN U.S. WHICH WILL CUT OFF A
CLOSED LOW ACROSS THE DESERT SOUTHWEST/MEXICO BORDER BY TONIGHT.
THIS WILL EVOLVE NORTHEAST IN RESPONSE TO ANOTHER JET MAXIMUM
DIGGING UPSTREAM. A CUTOFF FEATURE SUCH AS THIS LOW AND BEING
FAIRLY FAR SOUTH IN LATITUDE TENDS TO END UP BEING SLOWER THAN A
MEAN MODEL SOLUTION AND WE HAVE SEEN THAT OVER THE PAST COUPLE
MONTHS WITH SYSTEMS LOCATED EVEN FURTHER NORTH. SUCH A SLOWER
EVOLUTION WOULD RESULT IN A FURTHER WEST TRACK AS THE SYSTEM LIFTS
NORTHEAST WHICH IS ADVERTISED BY THE PREFERRED EC...NAM...AND
SREF MORE SO THAN THE GFS...ITS ENSEMBLE...AND THE GEM. THE
OVERALL TREND IN A MEAN OF ALL THESE GUIDANCE HAS ALSO SHIFTED
SLIGHTLY SLOWER AND FURTHER WEST WITH THIS SYSTEM...FURTHER
SUPPORTING LEANING THIS ROUTE. IN ADDITION...THE STRONG CANADIAN
HIGH PRESSURE OVER THE NORTHERN PLAINS THAT COULD OFFER SOME
BLOCKING AND SUPPORT A FURTHER EAST TRACK IN THE LOW IS TRENDING
SLIGHTLY FURTHER NORTH...AGAIN FAVORING LEANING WEST.
FOR SUNDAY...LOW-LEVEL COLD ADVECTION ON GUSTY NORTHERLY WINDS
WILL BE UNDERCUTTING THE ELEVATED BAROCLINIC ZONE AND EXPECT
TEMPERATURES TO REMAIN IN THE 30S BUT FEELING EVEN COLDER. THERE
PROBABLY WILL BE LAKE EFFECT CLOUDS AND MAYBE EVEN SOME DRIZZLE
FROM THAT DURING THE MORNING INTO CHICAGO AND OTHER LAKE ADJACENT
AREAS. AS FOR THE PREVAILING RAIN IN THE SOUTHERN AND EASTERN
FORECAST AREA SUNDAY MORNING...THAT SHOULD EASE SOUTHEASTWARD IN
THE AFTERNOON AS FRONTOGENESIS TEMPORARILY WEAKENS.
THE WARM AND MOIST ADVECTION ALOFT GRADUALLY STRENGTHENS SUNDAY
EVENING IN RESPONSE TO THE UPPER LOW APPROACHING AND REALLY RAMPS UP
EITHER LATE THAT NIGHT OR MONDAY MORNING OVER THE AREA. THE NAM
IS THE SLOWEST ADVANCING ITS PRECIPITATION AND IF CORRECT WOULD
INDICATE NOT MUCH IN THE AREA PRIOR TO DAYBREAK MONDAY...BUT HAVE
LEANED A LITTLE QUICKER THAN ITS SOLUTION GIVEN THE STRENGTH OF
THE MOISTURE ADVECTION.
EASTERLY SURFACE WINDS WILL STRENGTHEN OVERNIGHT GIVEN THE
PRESSURE GRADIENT RAPIDLY TIGHTENING. THIS ALONG WITH CLOUDS
SHOULD KEEP TEMPERATURES FAIRLY STEADY...THOUGH AS MENTIONED IN
PRIOR AFD THAT AT PRECIP ONSET...WHETHER LATE SUNDAY NIGHT OR
MONDAY MORNING...MAY RESULT IN A COUPLE DEGREE TEMPERATURE DROP.
THIS COULD MEAN A WINDOW OF SOME SLEET BUT OVERALL NOT EXPECTING
THAT TO BE THE DOMINANT TYPE OF PRECIPITATION FOR ANY EXTENDED
PERIOD. WITH BIG TIME UPPER SUPPORT FOR LIFT...PRECIPITATION
SHOULD BE AT ITS MAXIMUM COVERAGE AND INTENSITY DURING THE DAY
MONDAY AND AT LEAST EARLY MONDAY EVENING...IF NOT MUCH OF IT.
MIXING RATIOS OF 6-8 G/KG SHOULD SUPPORT MODEST IF NOT TEMPORARILY
HEAVY RATES...AND OBVIOUSLY THATS WHERE CONCERNS ARE REALLY
HEIGHTENED WITH ANY FREEZING RAIN.
GIVEN THE QUICK UPTICK IN INTENSITY OF RAINFALL AND EASTERLY
SURFACE WINDS...HAVE CONTINUED TO KEEP TEMPERATURES SLOW TO WARM
DURING THE DAY. TEMPERATURES STILL SHOULD BE INCHING UP TO OR EVEN
ABOVE FREEZING FROM SOUTH TO NORTH ACROSS THE AREA...BUT THAT
LOOKS LIKE IT WILL LAG THE ONSET OF MODERATE PRECIPITATION AND
THUS CONTINUE WITH FORECAST ICE ACCUMULATION IN THE CWA...NAMELY
THE NORTHERN HALF AWAY FROM THE IMMEDIATE LAKE. FOR AREAS ADJACENT
TO LAKE MICHIGAN...INCLUDING DOWNTOWN CHICAGO...STIFF ONSHORE FLOW
GUSTING TO 40 MPH PLUS /ESPECIALLY NEAR THE LAKE SHORE/ SHOULD
KEEP TEMPERATURES JUST ABOVE FREEZING. TEMPERATURES DO NOT LOOK TO
BE SIGNIFICANTLY BELOW FREEZING WHERE THEY ARE SUB 32...WHICH IS
ONE THING THAT COULD HELP EASE IMPACTS. IF HOWEVER ICE ACCRETION
DOES BEGIN ON LIMBS OR POWER LINES AND OVER SEVERAL HOURS...THE
STRONG WINDS COULD ALLOW FOR HIGHER IMPACTS.
AGAIN IN SUMMARY...THINGS GOING FOR THIS EVENT ARE A STIFF EAST WIND
AND A WIDESPREAD PRECIPITATION SHIELD TO KEEP THE SURFACE
TEMPERATURES FROM WARMING RAPIDLY...OR AT LEAST MORE RAPIDLY THAN
EVEN THE WARMEST GUIDANCE...AND THUS ALLOW FOR WHAT APPEARS TO BE
SEVERAL HOUR DURATION OF FREEZING RAIN. MOST CONCERNED FOR NORTH
CENTRAL ILLINOIS...INCLUDING ROCKFORD...WHERE COLLABORATED ICE
FORECASTS WITH WPC AND ADJACENT WFOS IS PRESENTLY AT OR ABOVE 0.20
OF AN INCH.
TUESDAY STILL LOOKS TO OFFER SOME SNOW POSSIBILITY ON THE
BACKSIDE OF THE SYSTEM...THOUGH WITH IT FILLING AM NOT EXPECTING A
WELL- DEFINED DEFORMATION/WRAPAROUND AS FAR EAST AS THE CWA.
TEMPERATURES LOOK TO EASE DOWN THROUGH THE WEEK INTO UNFAMILIAR
TERRITORY OF BELOW NORMAL BY THE START TO 2016. THERE CONTINUES
TO BE A CHANCE OF SNOW ON WEDNESDAY BUT HAVE GONE WITH A WELL-
VERIFYING MODEL BLEND AT THIS TIME TO FOCUS ON THE PREVIOUS
SYSTEMS.
MTF
&&
.HYDROLOGY...
RAIN DEVELOPING ALONG A STATIONARY FRONT DURING THE DAY
TODAY...AND POSSIBLY HEAVY AT TIMES LATE THIS AFTERNOON TONIGHT...IS
LIKELY TO PERSIST THROUGH EARLY SUNDAY MORNING. THUNDERSTORMS
ALSO ARE POSSIBLE ACROSS SOUTHERN PORTIONS OF THE AREA MAINLY
SOUTH OF THE KANKAKEE RIVER...WHERE WIDESPREAD 1.5 TO 2 INCH
RAINFALL AMOUNTS ARE MOST LIKELY. LOCALIZED AMOUNTS IN EXCESS OF 3
INCHES REMAIN POSSIBLE...THOUGH AT THIS TIME THIS MAY OCCUR JUST
SOUTH OF THE LOCAL AREA. REGARDLESS...THESE RAINFALL AMOUNTS MAY
RESULT IN SIGNIFICANT RISES AND POSSIBLE FLOODING ALONG AREA
RIVERS AND STREAMS...INCLUDING THE IROQUOIS AND KANKAKEE RIVERS AS
WELL AS SUGAR CREEK. IN ADDITION...THE HEAVY RAIN WILL LIKELY
RESULT IN SOME PONDING OF WATER IN LOW LYING AND POOR DRAINAGE
AREAS. SEE THE CURRENT FFALOT FOR MORE DETAILS. THIS APPEARS TO BE
MORE OF A FLOODING SITUATION THAN A TRUE FLASH FLOOD
SITUATION...BUT GIVEN THE CONVECTIVE ELEMENT TO THE PRECIPITATION
AND THE EFFICIENCY OF THE PRECIPITATION EXPECTED TONIGHT AND
SATURATED GROUND...FLOODING COULD OCCUR QUICKLY FOR AREAS STUCK
UNDER HEAVY RAINFALL. THE FLOOD WATCH FOR OUR SOUTHERN COUNTIES WILL
ALSO ACCOUNT FOR ANOTHER 1-1.5 INCHES OF RAINFALL EXPECTED ON
MONDAY.
KMD
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* -RA/SHRA TRANSITIONING OVER TO DRIZZLE FOR THE REMAINDER OF THE
AFTERNOON THROUGH LATE TONIGHT...THOUGH A FEW LINGERING RAIN
SHOWERS WILL BE POSSIBLE THROUGH AROUND SUNSET. ANOTHER PERIOD
OF -RA LATE TONIGHT.
* IFR CIGS LIKELY THROUGH EARLY EVENING...THEN LIFR CIGS LIKELY
FOR THE LATE EVENING HOURS...BUT IMPROVING TO MVFR DURG THE LATE
NIGHT HOURS.
* EAST WINDS REMAIN ARND 5 TO 10 KT THROUGH LATE AFTERNOON
BACKING NNELY THIS EVENING. WINDS STRENGTHENING AND BECOMING
GUSTY TO ARND 25KT LATE TONIGHT AND TOMORROW.
KREIN
//DISCUSSION...UPDATED 18Z...
A MID LEVEL IMPULSE TRACKING ACROSS THE REGION HAS BROUGHT AN AREA
OF RAIN WITH MVFR CIGS/VIS AND OCNL IFR VIS IN HEAVIER SHOWERS.
SOME ISOLD EMBEDDED TS HAS BEEN OBSERVED WITHIN THE RAIN
AREA...BUT ANY TS HAVE REMAINED SOUTH AND EAST OF THE TERMINALS.
TS POTENTIAL SHOULD END BY 19-20Z AS THE IMPULSE MOVES OFF TO THE
NORTHEAST. MID LEVEL DRY AIR WILL OVERSPREAD THE REGION BEHIND THE
EXITING MID LEVEL IMPULSE...AND RAIN SHOULD TRANSITION OVER TO
DRIZZLE. WITH THE LOWER LEVELS REMAINING VERY MOIST...EXPECT THAT
CIGS/VIS SHOULD LOWER TO PREVAILING IFR BY SUNSET...WITH THE
POTENTIAL FOR LIFR CIGS OVERNIGHT. A MODEST PRESSURE GRADIENT
SHOULD KEEP NNELY WINDS OF 5-10KT THROUGH THE LATE NIGHT
HOURS...SO DO NOT EXPECT DENSE FOG TO FORM. DURG THE EARLY MORNING
HOURS...AS DEEPENING LOW PRESSURE LIFTS NORTHEAST OUT OF ERN
OKLAHOMA THROUGH MISSOURI TOMORROW...EXPECT A STRENGTHENING NNELY
PRESSURE GRADIENT...WITH WINDS GUSTING TO 25KT BY ARND 12Z
TOMORROW MORNING AND SUSTAINED WINDS AND GUSTS LIKELY INCREASING
THROUGH THE DAY TOMORROW AS THE LOW MOVES TO SERN IOWA LATE
TOMORROW AFTERNOON.
KREIN
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* MEDIUM CONFIDENCE IN PRECIP/VISBY TRENDS.
* HIGH CONFIDENCE IN IFR/LIFR CIGS...MEDIUM CONFIDENCE IN TIMING
OF IFR/LIFR CIGS.
* MEDIUM-HIGH CONFIDENCE IN WIND TRENDS.
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT...WINTRY MIX POSSIBLE LATE. MVFR CIGS PSBL.
MONDAY...WINTRY MIX TURNING TO RAIN. MVFR CIGS AND VSBYS.
TUESDAY...MVFR CIGS. CHANCE OF -SN/RA IN THE MORNING.
WEDNESDAY...MVFR CIGS. CHANCE OF -SN.
THURSDAY...MVFR CIGS.
FRIDAY...DRY. VFR.
KMD
&&
.MARINE...
456 AM CST
.HIGH PRESSURE OVER THE NORTHERN LAKES WILL QUICKLY MOVE EAST
TODAY...WHILE LOW PRESSURE DEVELOPS OVER THE SOUTHERN PLAINS. THIS
LOW WILL MOVE QUICKLY NORTHEAST ACROSS THE MIDWEST THIS AFTERNOON
AND INTO NEW ENGLAND BY EARLY SUNDAY. EXPECT WINDS TO RAMP UP
BETWEEN THESE TWO FEATURES RESULTING IN SOME HIGHER WAVES ALONG
THE ILLINOIS SIDE TODAY. STRONG HIGH PRESSURE OVER THE UPPER
MIDWEST EXTENDING INTO SOUTHERN MANITOBA WILL BUILD EAST ACROSS
ONTARIO LATE IN THE WEEKEND...WHILE ANOTHER DEEP LOW DEVELOPS
ACROSS TEXAS. AHEAD OF THE STRONG HIGH...A SURGE OF NORTH WINDS TO
30 KT...POSSIBLY A FEW GALE GUSTS...WILL OCCUR LATE TONIGHT INTO
SUNDAY.
THIS SECOND LOW WILL THEN DEEPEN OVER THE LOWER MISSOURI VALLEY
MONDAY MORNING...THEN WILL LIFT NORTHEAST ACROSS WESTERN GREAT
LAKES BY EARLY TUESDAY BEFORE FILLING. THE GRADIENT BETWEEN THIS
LOW AND THE VERY STRONG HIGH WHICH ONLY SLOWLY MOVES EAST WILL
RESULT IN A PERIOD OF STRONG GALES MONDAY...POSSIBLY WITH A FEW
STORM FORCE WIND GUSTS ALONG WITH COASTAL FLOODING ISSUES ALONG
THE ILLINOIS NEARSHORE. ANOTHER WEAK LOW WILL MOVE OVER THE
NORTHERN HALF OF THE LAKE WEDNESDAY FOLLOWED BY COOL HIGH
PRESSURE.
KMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLASH FLOOD WATCH...ILZ033-ILZ039...6 PM SATURDAY TO 6 PM MONDAY.
IN...FLASH FLOOD WATCH...INZ010-INZ011-INZ019...6 PM SATURDAY TO 6 PM
MONDAY.
LM...SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 6 PM SATURDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
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WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1155 AM CST SAT DEC 26 2015
.UPDATE...
1108 AM CST
TSRA COVERAGE SEEMS TO BE ON A DOWNWARD TREND LATE THIS MORNING
AFTER A LITTLE MORE ACTIVITY SOUTH AND WEST THAN MIGHT HAVE BEEN
EXPECTED EARLIER TODAY. FOCUS FOR ADDITIONAL TSRA WILL SHIFT
WELL SOUTH OF THE CHICAGO METRO AREA MAINLY TO PORTIONS OF NW
INDIANA ALONG WITH THE ANTICIPATED AXIS OF HEAVIER RAINFALL. MAY
EVEN BE ABLE TO LOWER POPS IN NORTHERN PORTIONS OF THE AREA TOWARD
ROCKFORD AND THE WI LINE THIS AFTERNOON...OR CARRY JUST A MENTION
OF DRIZZLE. EVEN IN THE CHICAGO METRO AREA...DRIZZLE MIGHT BE THE
MAIN WEATHER TYPE THIS AFTERNOON AS THE LATEST AMDAR SOUNDINGS OUT
OF MDW ARE SHOWING JUST A RELATIVELY SHALLOW SATURATED LAYER TO
ABOUT 850 MB WITH DRY AIR ABOVE THAT. THIS ALSO CORRESPONDS TO
WHAT THE RAP IS SHOWING...WITH AN INCREASINGLY SHALLOW SATURATED
LAYER AS THE AFTERNOON PROGRESSES.
WINDS WILL RELAX THIS AFTERNOON AND TONIGHT BEFORE PICKING UP
CONSIDERABLY AGAIN TOMORROW MORNING.
LENNING
&&
.SHORT TERM...
411 AM CST
THROUGH TONIGHT...
FOCUS IS ON MODERATE TO LOCALLY HEAVY RAINFALL LATE THIS AFTERNOON
THROUGH TONIGHT.
DEEP UPPER LEVEL LOW PRESSURE CONTINUES TO STRENGTHEN OVER THE
DESTER SOUTHWEST...WITH STRONG AND UNSEASONABLY MOIST/WARM
ADVECTION OCCURRING OUT AHEAD OF THE LOW. SEVERAL COMPLEXES OF
THUNDERSTORMS ARE ONGOING IN THE WARM ADVECTIVE REGIME NORTH OF A
WARM FRONTAL BOUNDARY DRAPED FROM THE ARKLATEX REGION THEN
NORTHEAST INTO THE TENNESSEE VALLEY IN AN AREA OF ELEVATED MID
LEVEL LAPSE RATES. AN ADDITIONAL AREA OF PRECIPITATION IS
OCCURRING NORTH OF AN INVERTED SURFACE TROUGH.
THIS WARM/MOIST BOUNDARY CONTINUES TO ADVECT NORTHWARD THIS
MORNING WITH A PLUME OF NEAR RECORD PRECIPITABLE WATER VALUES.
WITH COOL NORTHEAST WINDS IN PLACE AHEAD ANCHORING THE LOW LEVEL
FRONTAL BOUNDARY TO OUR SOUTH WILL CREATE A RECIPE FOR LOW CLOUDS
TO OVERSPREAD THE AREA THIS MORNING...AS FORECAST SOUNDINGS
DEPICT RAPID SATURATION OF THE LOWER LEVELS WHICH HAS BEEN
OCCURRING DOWNSTATE. AS CLOUDS LOWER...EXPECT SOME FOG TO DEVELOP
AS WELL.
THE INVERTED TROUGH AXIS SHIFTS AND IS POINTED AT OUR AREA AROUND
MIDDAY. AS THIS OCCURS IN CONJUNCTION WITH ISENTROPIC
ASCENT...EXPECT AN INCREASE IN INITIALLY LIGHTER RAIN SHOWERS THIS
MORNING DUE TO LACK OF DEEPER SATURATION...THEN AS FORCING
INCREASES AHEAD OF A NORTHERN STREAM SHORTWAVE...STRENGTHENING
UPPER LEVEL JET MAXIMUM TO OUR NORTHWEST...AND A STRONG LOW TO MID
LEVEL FRONTOGENESIS OCCURRING DUE TO THE AIRMASS CLASH...EXPECT
SHOWERS TO BLOSSOM THIS AFTERNOON AND EVENING. PRECIPITATION MAY
DWINDLE TO LIGHTER RAIN/DRIZZLE FARTHER NORTH...BUT THERE ARE
ADDITIONAL WAVES THAT WILL RIDE ALONG THE LOW AND ELEVATED
BAROCLINIC ZONES TO KEEP A MENTION OF RAIN GOING AREA-WIDE TONIGHT.
THE FRONT LOOKS TO BE MOST ACTIVE ALONG OUR SOUTHERN COUNTIES
WHERE EXTREME FRONTOGENESIS COMBINED WITH THE RECORD PWATS WILL
LEAD TO PERIODS OF MODERATE TO HEAVY RAINFALL. THUNDER IS
CERTAINLY POSSIBLE EVEN AS FAR NORTH AS CHICAGO OR LAKE MICHIGAN
AS THE PLUME OF ELEVATED LAPSE RATES SPREADS OVERHEAD...BUT MORE
LIKELY FARTHER SOUTH CLOSER TO THE STRONGER COMBINED FORCING.
THERE LOOKS TO BE A VERY TIGHT GRADIENT IN THE HEAVY PRECIP AXIS.
HAVE ELECTED TO ISSUE A FLOOD WATCH SIMILAR TO OUR NEIGHBORS DUE
TO THIS POTENTIAL GIVEN THE CONVECTIVE ELEMENTS PRESENT. THERE IS
STILL WITH SOME UNCERTAINTY AS TO IF THIS WILL REMAIN SOUTH OF THE
AREA AS SUGGESTED BY SOME HI-RES GUIDANCE MEMBERS. HAVE CARRIED
THIS WATCH OUT THROUGH THE SECOND EVENT (LONG TERM)...THOUGH THERE
WILL BE A GAP ON SUNDAY. MORE ON THIS IN THE HYDROLOGY SECTION
FORTHCOMING.
KMD
&&
.LONG TERM...
333 AM CST
SUNDAY THROUGH FRIDAY...
THE FOCUS ON THE LONGER RANGE FORECAST IS CERTAINLY WITH THE SUNDAY
NIGHT THROUGH MONDAY NIGHT PRECIPITATION EVENT...WHICH IS TRENDING
MORE TOWARD A RAIN/FREEZING RAIN EVENT. THIS STILL LOOKS TO BE LARGE
CONCERNS OF ICING FROM FREEZING RAIN FOR AT LEAST A PORTION OF THE
AREA...ESPECIALLY AREAS ALONG AND NORTH OF I-80. THERE ALSO IS
CONCERNS THAT THE AMOUNT OF RAIN /WHETHER INITIALLY FREEZING OR NOT/
COULD CAUSE LOCALIZED FLOODING ISSUES AS MONDAY PROGRESSES AND
CERTAINLY SOME QUICK RIVER RISES. IT IS A BIT CLEARER PICTURE THAT
THE POTENTIAL FOR SNOW IS LESS LIKELY THROUGH MONDAY NIGHT. HAVE
ADDED A LITTLE MORE DETAIL IN THE FORECAST...BUT OVERALL KEPT SOME
RANGE OF UNCERTAINTY DUE TO THE SPECIFIC SURFACE TEMPERATURE
FORECASTS AS WELL AS THE LARGER SCALE EXACT TRACK OF THE SYSTEM.
LAST EVENINGS RAOBS INDICATED A STRONG JET STREAM MAXIMUM OF AROUND
150 KT DIGGING SOUTH ACROSS THE WESTERN U.S. WHICH WILL CUT OFF A
CLOSED LOW ACROSS THE DESERT SOUTHWEST/MEXICO BORDER BY TONIGHT.
THIS WILL EVOLVE NORTHEAST IN RESPONSE TO ANOTHER JET MAXIMUM
DIGGING UPSTREAM. A CUTOFF FEATURE SUCH AS THIS LOW AND BEING
FAIRLY FAR SOUTH IN LATITUDE TENDS TO END UP BEING SLOWER THAN A
MEAN MODEL SOLUTION AND WE HAVE SEEN THAT OVER THE PAST COUPLE
MONTHS WITH SYSTEMS LOCATED EVEN FURTHER NORTH. SUCH A SLOWER
EVOLUTION WOULD RESULT IN A FURTHER WEST TRACK AS THE SYSTEM LIFTS
NORTHEAST WHICH IS ADVERTISED BY THE PREFERRED EC...NAM...AND
SREF MORE SO THAN THE GFS...ITS ENSEMBLE...AND THE GEM. THE
OVERALL TREND IN A MEAN OF ALL THESE GUIDANCE HAS ALSO SHIFTED
SLIGHTLY SLOWER AND FURTHER WEST WITH THIS SYSTEM...FURTHER
SUPPORTING LEANING THIS ROUTE. IN ADDITION...THE STRONG CANADIAN
HIGH PRESSURE OVER THE NORTHERN PLAINS THAT COULD OFFER SOME
BLOCKING AND SUPPORT A FURTHER EAST TRACK IN THE LOW IS TRENDING
SLIGHTLY FURTHER NORTH...AGAIN FAVORING LEANING WEST.
FOR SUNDAY...LOW-LEVEL COLD ADVECTION ON GUSTY NORTHERLY WINDS
WILL BE UNDERCUTTING THE ELEVATED BAROCLINIC ZONE AND EXPECT
TEMPERATURES TO REMAIN IN THE 30S BUT FEELING EVEN COLDER. THERE
PROBABLY WILL BE LAKE EFFECT CLOUDS AND MAYBE EVEN SOME DRIZZLE
FROM THAT DURING THE MORNING INTO CHICAGO AND OTHER LAKE ADJACENT
AREAS. AS FOR THE PREVAILING RAIN IN THE SOUTHERN AND EASTERN
FORECAST AREA SUNDAY MORNING...THAT SHOULD EASE SOUTHEASTWARD IN
THE AFTERNOON AS FRONTOGENESIS TEMPORARILY WEAKENS.
THE WARM AND MOIST ADVECTION ALOFT GRADUALLY STRENGTHENS SUNDAY
EVENING IN RESPONSE TO THE UPPER LOW APPROACHING AND REALLY RAMPS UP
EITHER LATE THAT NIGHT OR MONDAY MORNING OVER THE AREA. THE NAM
IS THE SLOWEST ADVANCING ITS PRECIPITATION AND IF CORRECT WOULD
INDICATE NOT MUCH IN THE AREA PRIOR TO DAYBREAK MONDAY...BUT HAVE
LEANED A LITTLE QUICKER THAN ITS SOLUTION GIVEN THE STRENGTH OF
THE MOISTURE ADVECTION.
EASTERLY SURFACE WINDS WILL STRENGTHEN OVERNIGHT GIVEN THE
PRESSURE GRADIENT RAPIDLY TIGHTENING. THIS ALONG WITH CLOUDS
SHOULD KEEP TEMPERATURES FAIRLY STEADY...THOUGH AS MENTIONED IN
PRIOR AFD THAT AT PRECIP ONSET...WHETHER LATE SUNDAY NIGHT OR
MONDAY MORNING...MAY RESULT IN A COUPLE DEGREE TEMPERATURE DROP.
THIS COULD MEAN A WINDOW OF SOME SLEET BUT OVERALL NOT EXPECTING
THAT TO BE THE DOMINANT TYPE OF PRECIPITATION FOR ANY EXTENDED
PERIOD. WITH BIG TIME UPPER SUPPORT FOR LIFT...PRECIPITATION
SHOULD BE AT ITS MAXIMUM COVERAGE AND INTENSITY DURING THE DAY
MONDAY AND AT LEAST EARLY MONDAY EVENING...IF NOT MUCH OF IT.
MIXING RATIOS OF 6-8 G/KG SHOULD SUPPORT MODEST IF NOT TEMPORARILY
HEAVY RATES...AND OBVIOUSLY THATS WHERE CONCERNS ARE REALLY
HEIGHTENED WITH ANY FREEZING RAIN.
GIVEN THE QUICK UPTICK IN INTENSITY OF RAINFALL AND EASTERLY
SURFACE WINDS...HAVE CONTINUED TO KEEP TEMPERATURES SLOW TO WARM
DURING THE DAY. TEMPERATURES STILL SHOULD BE INCHING UP TO OR EVEN
ABOVE FREEZING FROM SOUTH TO NORTH ACROSS THE AREA...BUT THAT
LOOKS LIKE IT WILL LAG THE ONSET OF MODERATE PRECIPITATION AND
THUS CONTINUE WITH FORECAST ICE ACCUMULATION IN THE CWA...NAMELY
THE NORTHERN HALF AWAY FROM THE IMMEDIATE LAKE. FOR AREAS ADJACENT
TO LAKE MICHIGAN...INCLUDING DOWNTOWN CHICAGO...STIFF ONSHORE FLOW
GUSTING TO 40 MPH PLUS /ESPECIALLY NEAR THE LAKE SHORE/ SHOULD
KEEP TEMPERATURES JUST ABOVE FREEZING. TEMPERATURES DO NOT LOOK TO
BE SIGNIFICANTLY BELOW FREEZING WHERE THEY ARE SUB 32...WHICH IS
ONE THING THAT COULD HELP EASE IMPACTS. IF HOWEVER ICE ACCRETION
DOES BEGIN ON LIMBS OR POWER LINES AND OVER SEVERAL HOURS...THE
STRONG WINDS COULD ALLOW FOR HIGHER IMPACTS.
AGAIN IN SUMMARY...THINGS GOING FOR THIS EVENT ARE A STIFF EAST WIND
AND A WIDESPREAD PRECIPITATION SHIELD TO KEEP THE SURFACE
TEMPERATURES FROM WARMING RAPIDLY...OR AT LEAST MORE RAPIDLY THAN
EVEN THE WARMEST GUIDANCE...AND THUS ALLOW FOR WHAT APPEARS TO BE
SEVERAL HOUR DURATION OF FREEZING RAIN. MOST CONCERNED FOR NORTH
CENTRAL ILLINOIS...INCLUDING ROCKFORD...WHERE COLLABORATED ICE
FORECASTS WITH WPC AND ADJACENT WFOS IS PRESENTLY AT OR ABOVE 0.20
OF AN INCH.
TUESDAY STILL LOOKS TO OFFER SOME SNOW POSSIBILITY ON THE
BACKSIDE OF THE SYSTEM...THOUGH WITH IT FILLING AM NOT EXPECTING A
WELL- DEFINED DEFORMATION/WRAPAROUND AS FAR EAST AS THE CWA.
TEMPERATURES LOOK TO EASE DOWN THROUGH THE WEEK INTO UNFAMILIAR
TERRITORY OF BELOW NORMAL BY THE START TO 2016. THERE CONTINUES
TO BE A CHANCE OF SNOW ON WEDNESDAY BUT HAVE GONE WITH A WELL-
VERIFYING MODEL BLEND AT THIS TIME TO FOCUS ON THE PREVIOUS
SYSTEMS.
MTF
&&
.HYDROLOGY...
RAIN DEVELOPING ALONG A STATIONARY FRONT DURING THE DAY
TODAY...AND POSSIBLY HEAVY AT TIMES LATE THIS AFTERNOON TONIGHT...IS
LIKELY TO PERSIST THROUGH EARLY SUNDAY MORNING. THUNDERSTORMS
ALSO ARE POSSIBLE ACROSS SOUTHERN PORTIONS OF THE AREA MAINLY
SOUTH OF THE KANKAKEE RIVER...WHERE WIDESPREAD 1.5 TO 2 INCH
RAINFALL AMOUNTS ARE MOST LIKELY. LOCALIZED AMOUNTS IN EXCESS OF 3
INCHES REMAIN POSSIBLE...THOUGH AT THIS TIME THIS MAY OCCUR JUST
SOUTH OF THE LOCAL AREA. REGARDLESS...THESE RAINFALL AMOUNTS MAY
RESULT IN SIGNIFICANT RISES AND POSSIBLE FLOODING ALONG AREA
RIVERS AND STREAMS...INCLUDING THE IROQUOIS AND KANKAKEE RIVERS AS
WELL AS SUGAR CREEK. IN ADDITION...THE HEAVY RAIN WILL LIKELY
RESULT IN SOME PONDING OF WATER IN LOW LYING AND POOR DRAINAGE
AREAS. SEE THE CURRENT FFALOT FOR MORE DETAILS. THIS APPEARS TO BE
MORE OF A FLOODING SITUATION THAN A TRUE FLASH FLOOD
SITUATION...BUT GIVEN THE CONVECTIVE ELEMENT TO THE PRECIPITATION
AND THE EFFICIENCY OF THE PRECIPITATION EXPECTED TONIGHT AND
SATURATED GROUND...FLOODING COULD OCCUR QUICKLY FOR AREAS STUCK
UNDER HEAVY RAINFALL. THE FLOOD WATCH FOR OUR SOUTHERN COUNTIES WILL
ALSO ACCOUNT FOR ANOTHER 1-1.5 INCHES OF RAINFALL EXPECTED ON
MONDAY.
KMD
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* RA/SHRA THROUGH EARLY AFTERNOON AND THEN TRANSITIONING OVER TO
DRIZZLE FOR THE EARLY EVENING THROUGH LATE TONIGHT. ANOTHER
POSSIBLE PERIOD OF -RA LATE TONIGHT.
* MVFR CIGS DROPPING TO IFR EARLY THIS EVENING. LIFR CIGS LIKELY
FOR THE LATE EVENING HOURS...BUT IMPROVING TO MVFR DURG THE LATE
NIGHT HOURS.
* EAST WINDS REMAIN ABOVE 10 KT THROUGH LATE AFTERNOON BACKING
NNELY THIS EVENING. WINDS STRENGTHENING AND BECOMING GUSTY TO
ARND 25KT LATE TONIGHT AND TOMORROW.
KREIN
//DISCUSSION...UPDATED 18Z...
A MID LEVEL IMPULSE TRACKING ACROSS THE REGION HAS BROUGHT AN AREA
OF RAIN WITH MVFR CIGS/VIS AND OCNL IFR VIS IN HEAVIER SHOWERS.
SOME ISOLD EMBEDDED TS HAS BEEN OBSERVED WITHIN THE RAIN
AREA...BUT ANY TS HAVE REMAINED SOUTH AND EAST OF THE TERMINALS.
TS POTENTIAL SHOULD END BY 19-20Z AS THE IMPULSE MOVES OFF TO THE
NORTHEAST. MID LEVEL DRY AIR WILL OVERSPREAD THE REGION BEHIND THE
EXITING MID LEVEL IMPULSE...AND RAIN SHOULD TRANSITION OVER TO
DRIZZLE. WITH THE LOWER LEVELS REMAINING VERY MOIST...EXPECT THAT
CIGS/VIS SHOULD LOWER TO PREVAILING IFR BY SUNSET...WITH THE
POTENTIAL FOR LIFR CIGS OVERNIGHT. A MODEST PRESSURE GRADIENT
SHOULD KEEP NNELY WINDS OF 5-10KT THROUGH THE LATE NIGHT
HOURS...SO DO NOT EXPECT DENSE FOG TO FORM. DURG THE EARLY MORNING
HOURS...AS DEEPENING LOW PRESSURE LIFTS NORTHEAST OUT OF ERN
OKLAHOMA THROUGH MISSOURI TOMORROW...EXPECT A STRENGTHENING NNELY
PRESSURE GRADIENT...WITH WINDS GUSTING TO 25KT BY ARND 12Z
TOMORROW MORNING AND SUSTAINED WINDS AND GUSTS LIKELY INCREASING
THROUGH THE DAY TOMORROW AS THE LOW MOVES TO SERN IOWA LATE
TOMORROW AFTERNOON.
KREIN
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* MEDIUM CONFIDENCE IN PRECIP/VISBY TRENDS.
* HIGH CONFIDENCE IN CIGS DROPPING TO IFR/LIFR...MEDIUM CONFIDENCE
IN TIMING OF IFR/LIFR CIGS.
* MEDIUM-HIGH CONFIDENCE IN WIND TRENDS.
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT...WINTRY MIX POSSIBLE LATE. MVFR CIGS PSBL.
MONDAY...WINTRY MIX TURNING TO RAIN. MVFR CIGS AND VSBYS.
TUESDAY...MVFR CIGS. CHANCE OF -SN/RA IN THE MORNING.
WEDNESDAY...MVFR CIGS. CHANCE OF -SN.
THURSDAY...MVFR CIGS.
FRIDAY...DRY. VFR.
KMD
&&
.MARINE...
456 AM CST
.HIGH PRESSURE OVER THE NORTHERN LAKES WILL QUICKLY MOVE EAST
TODAY...WHILE LOW PRESSURE DEVELOPS OVER THE SOUTHERN PLAINS. THIS
LOW WILL MOVE QUICKLY NORTHEAST ACROSS THE MIDWEST THIS AFTERNOON
AND INTO NEW ENGLAND BY EARLY SUNDAY. EXPECT WINDS TO RAMP UP
BETWEEN THESE TWO FEATURES RESULTING IN SOME HIGHER WAVES ALONG
THE ILLINOIS SIDE TODAY. STRONG HIGH PRESSURE OVER THE UPPER
MIDWEST EXTENDING INTO SOUTHERN MANITOBA WILL BUILD EAST ACROSS
ONTARIO LATE IN THE WEEKEND...WHILE ANOTHER DEEP LOW DEVELOPS
ACROSS TEXAS. AHEAD OF THE STRONG HIGH...A SURGE OF NORTH WINDS TO
30 KT...POSSIBLY A FEW GALE GUSTS...WILL OCCUR LATE TONIGHT INTO
SUNDAY.
THIS SECOND LOW WILL THEN DEEPEN OVER THE LOWER MISSOURI VALLEY
MONDAY MORNING...THEN WILL LIFT NORTHEAST ACROSS WESTERN GREAT
LAKES BY EARLY TUESDAY BEFORE FILLING. THE GRADIENT BETWEEN THIS
LOW AND THE VERY STRONG HIGH WHICH ONLY SLOWLY MOVES EAST WILL
RESULT IN A PERIOD OF STRONG GALES MONDAY...POSSIBLY WITH A FEW
STORM FORCE WIND GUSTS ALONG WITH COASTAL FLOODING ISSUES ALONG
THE ILLINOIS NEARSHORE. ANOTHER WEAK LOW WILL MOVE OVER THE
NORTHERN HALF OF THE LAKE WEDNESDAY FOLLOWED BY COOL HIGH
PRESSURE.
KMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLASH FLOOD WATCH...ILZ033-ILZ039...6 PM SATURDAY TO 6 PM MONDAY.
IN...FLASH FLOOD WATCH...INZ010-INZ011-INZ019...6 PM SATURDAY TO 6 PM
MONDAY.
LM...SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 6 PM SATURDAY.
&&
$$
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1129 AM CST SAT DEC 26 2015
.UPDATE...
1108 AM CST
TSRA COVERAGE SEEMS TO BE ON A DOWNWARD TREND LATE THIS MORNING
AFTER A LITTLE MORE ACTIVITY SOUTH AND WEST THAN MIGHT HAVE BEEN
EXPECTED EARLIER TODAY. FOCUS FOR ADDITIONAL TSRA WILL SHIFT
WELL SOUTH OF THE CHICAGO METRO AREA MAINLY TO PORTIONS OF NW
INDIANA ALONG WITH THE ANTICIPATED AXIS OF HEAVIER RAINFALL. MAY
EVEN BE ABLE TO LOWER POPS IN NORTHERN PORTIONS OF THE AREA TOWARD
ROCKFORD AND THE WI LINE THIS AFTERNOON...OR CARRY JUST A MENTION
OF DRIZZLE. EVEN IN THE CHICAGO METRO AREA...DRIZZLE MIGHT BE THE
MAIN WEATHER TYPE THIS AFTERNOON AS THE LATEST AMDAR SOUNDINGS OUT
OF MDW ARE SHOWING JUST A RELATIVELY SHALLOW SATURATED LAYER TO
ABOUT 850 MB WITH DRY AIR ABOVE THAT. THIS ALSO CORRESPONDS TO
WHAT THE RAP IS SHOWING...WITH AN INCREASINGLY SHALLOW SATURATED
LAYER AS THE AFTERNOON PROGRESSES.
WINDS WILL RELAX THIS AFTERNOON AND TONIGHT BEFORE PICKING UP
CONSIDERABLY AGAIN TOMORROW MORNING.
LENNING
&&
.SHORT TERM...
411 AM CST
THROUGH TONIGHT...
FOCUS IS ON MODERATE TO LOCALLY HEAVY RAINFALL LATE THIS AFTERNOON
THROUGH TONIGHT.
DEEP UPPER LEVEL LOW PRESSURE CONTINUES TO STRENGTHEN OVER THE
DESTER SOUTHWEST...WITH STRONG AND UNSEASONABLY MOIST/WARM
ADVECTION OCCURRING OUT AHEAD OF THE LOW. SEVERAL COMPLEXES OF
THUNDERSTORMS ARE ONGOING IN THE WARM ADVECTIVE REGIME NORTH OF A
WARM FRONTAL BOUNDARY DRAPED FROM THE ARKLATEX REGION THEN
NORTHEAST INTO THE TENNESSEE VALLEY IN AN AREA OF ELEVATED MID
LEVEL LAPSE RATES. AN ADDITIONAL AREA OF PRECIPITATION IS
OCCURRING NORTH OF AN INVERTED SURFACE TROUGH.
THIS WARM/MOIST BOUNDARY CONTINUES TO ADVECT NORTHWARD THIS
MORNING WITH A PLUME OF NEAR RECORD PRECIPITABLE WATER VALUES.
WITH COOL NORTHEAST WINDS IN PLACE AHEAD ANCHORING THE LOW LEVEL
FRONTAL BOUNDARY TO OUR SOUTH WILL CREATE A RECIPE FOR LOW CLOUDS
TO OVERSPREAD THE AREA THIS MORNING...AS FORECAST SOUNDINGS
DEPICT RAPID SATURATION OF THE LOWER LEVELS WHICH HAS BEEN
OCCURRING DOWNSTATE. AS CLOUDS LOWER...EXPECT SOME FOG TO DEVELOP
AS WELL.
THE INVERTED TROUGH AXIS SHIFTS AND IS POINTED AT OUR AREA AROUND
MIDDAY. AS THIS OCCURS IN CONJUNCTION WITH ISENTROPIC
ASCENT...EXPECT AN INCREASE IN INITIALLY LIGHTER RAIN SHOWERS THIS
MORNING DUE TO LACK OF DEEPER SATURATION...THEN AS FORCING
INCREASES AHEAD OF A NORTHERN STREAM SHORTWAVE...STRENGTHENING
UPPER LEVEL JET MAXIMUM TO OUR NORTHWEST...AND A STRONG LOW TO MID
LEVEL FRONTOGENESIS OCCURRING DUE TO THE AIRMASS CLASH...EXPECT
SHOWERS TO BLOSSOM THIS AFTERNOON AND EVENING. PRECIPITATION MAY
DWINDLE TO LIGHTER RAIN/DRIZZLE FARTHER NORTH...BUT THERE ARE
ADDITIONAL WAVES THAT WILL RIDE ALONG THE LOW AND ELEVATED
BAROCLINIC ZONES TO KEEP A MENTION OF RAIN GOING AREA-WIDE TONIGHT.
THE FRONT LOOKS TO BE MOST ACTIVE ALONG OUR SOUTHERN COUNTIES
WHERE EXTREME FRONTOGENESIS COMBINED WITH THE RECORD PWATS WILL
LEAD TO PERIODS OF MODERATE TO HEAVY RAINFALL. THUNDER IS
CERTAINLY POSSIBLE EVEN AS FAR NORTH AS CHICAGO OR LAKE MICHIGAN
AS THE PLUME OF ELEVATED LAPSE RATES SPREADS OVERHEAD...BUT MORE
LIKELY FARTHER SOUTH CLOSER TO THE STRONGER COMBINED FORCING.
THERE LOOKS TO BE A VERY TIGHT GRADIENT IN THE HEAVY PRECIP AXIS.
HAVE ELECTED TO ISSUE A FLOOD WATCH SIMILAR TO OUR NEIGHBORS DUE
TO THIS POTENTIAL GIVEN THE CONVECTIVE ELEMENTS PRESENT. THERE IS
STILL WITH SOME UNCERTAINTY AS TO IF THIS WILL REMAIN SOUTH OF THE
AREA AS SUGGESTED BY SOME HI-RES GUIDANCE MEMBERS. HAVE CARRIED
THIS WATCH OUT THROUGH THE SECOND EVENT (LONG TERM)...THOUGH THERE
WILL BE A GAP ON SUNDAY. MORE ON THIS IN THE HYDROLOGY SECTION
FORTHCOMING.
KMD
&&
.LONG TERM...
333 AM CST
SUNDAY THROUGH FRIDAY...
THE FOCUS ON THE LONGER RANGE FORECAST IS CERTAINLY WITH THE SUNDAY
NIGHT THROUGH MONDAY NIGHT PRECIPITATION EVENT...WHICH IS TRENDING
MORE TOWARD A RAIN/FREEZING RAIN EVENT. THIS STILL LOOKS TO BE LARGE
CONCERNS OF ICING FROM FREEZING RAIN FOR AT LEAST A PORTION OF THE
AREA...ESPECIALLY AREAS ALONG AND NORTH OF I-80. THERE ALSO IS
CONCERNS THAT THE AMOUNT OF RAIN /WHETHER INITIALLY FREEZING OR NOT/
COULD CAUSE LOCALIZED FLOODING ISSUES AS MONDAY PROGRESSES AND
CERTAINLY SOME QUICK RIVER RISES. IT IS A BIT CLEARER PICTURE THAT
THE POTENTIAL FOR SNOW IS LESS LIKELY THROUGH MONDAY NIGHT. HAVE
ADDED A LITTLE MORE DETAIL IN THE FORECAST...BUT OVERALL KEPT SOME
RANGE OF UNCERTAINTY DUE TO THE SPECIFIC SURFACE TEMPERATURE
FORECASTS AS WELL AS THE LARGER SCALE EXACT TRACK OF THE SYSTEM.
LAST EVENINGS RAOBS INDICATED A STRONG JET STREAM MAXIMUM OF AROUND
150 KT DIGGING SOUTH ACROSS THE WESTERN U.S. WHICH WILL CUT OFF A
CLOSED LOW ACROSS THE DESERT SOUTHWEST/MEXICO BORDER BY TONIGHT.
THIS WILL EVOLVE NORTHEAST IN RESPONSE TO ANOTHER JET MAXIMUM
DIGGING UPSTREAM. A CUTOFF FEATURE SUCH AS THIS LOW AND BEING
FAIRLY FAR SOUTH IN LATITUDE TENDS TO END UP BEING SLOWER THAN A
MEAN MODEL SOLUTION AND WE HAVE SEEN THAT OVER THE PAST COUPLE
MONTHS WITH SYSTEMS LOCATED EVEN FURTHER NORTH. SUCH A SLOWER
EVOLUTION WOULD RESULT IN A FURTHER WEST TRACK AS THE SYSTEM LIFTS
NORTHEAST WHICH IS ADVERTISED BY THE PREFERRED EC...NAM...AND
SREF MORE SO THAN THE GFS...ITS ENSEMBLE...AND THE GEM. THE
OVERALL TREND IN A MEAN OF ALL THESE GUIDANCE HAS ALSO SHIFTED
SLIGHTLY SLOWER AND FURTHER WEST WITH THIS SYSTEM...FURTHER
SUPPORTING LEANING THIS ROUTE. IN ADDITION...THE STRONG CANADIAN
HIGH PRESSURE OVER THE NORTHERN PLAINS THAT COULD OFFER SOME
BLOCKING AND SUPPORT A FURTHER EAST TRACK IN THE LOW IS TRENDING
SLIGHTLY FURTHER NORTH...AGAIN FAVORING LEANING WEST.
FOR SUNDAY...LOW-LEVEL COLD ADVECTION ON GUSTY NORTHERLY WINDS
WILL BE UNDERCUTTING THE ELEVATED BAROCLINIC ZONE AND EXPECT
TEMPERATURES TO REMAIN IN THE 30S BUT FEELING EVEN COLDER. THERE
PROBABLY WILL BE LAKE EFFECT CLOUDS AND MAYBE EVEN SOME DRIZZLE
FROM THAT DURING THE MORNING INTO CHICAGO AND OTHER LAKE ADJACENT
AREAS. AS FOR THE PREVAILING RAIN IN THE SOUTHERN AND EASTERN
FORECAST AREA SUNDAY MORNING...THAT SHOULD EASE SOUTHEASTWARD IN
THE AFTERNOON AS FRONTOGENESIS TEMPORARILY WEAKENS.
THE WARM AND MOIST ADVECTION ALOFT GRADUALLY STRENGTHENS SUNDAY
EVENING IN RESPONSE TO THE UPPER LOW APPROACHING AND REALLY RAMPS UP
EITHER LATE THAT NIGHT OR MONDAY MORNING OVER THE AREA. THE NAM
IS THE SLOWEST ADVANCING ITS PRECIPITATION AND IF CORRECT WOULD
INDICATE NOT MUCH IN THE AREA PRIOR TO DAYBREAK MONDAY...BUT HAVE
LEANED A LITTLE QUICKER THAN ITS SOLUTION GIVEN THE STRENGTH OF
THE MOISTURE ADVECTION.
EASTERLY SURFACE WINDS WILL STRENGTHEN OVERNIGHT GIVEN THE
PRESSURE GRADIENT RAPIDLY TIGHTENING. THIS ALONG WITH CLOUDS
SHOULD KEEP TEMPERATURES FAIRLY STEADY...THOUGH AS MENTIONED IN
PRIOR AFD THAT AT PRECIP ONSET...WHETHER LATE SUNDAY NIGHT OR
MONDAY MORNING...MAY RESULT IN A COUPLE DEGREE TEMPERATURE DROP.
THIS COULD MEAN A WINDOW OF SOME SLEET BUT OVERALL NOT EXPECTING
THAT TO BE THE DOMINANT TYPE OF PRECIPITATION FOR ANY EXTENDED
PERIOD. WITH BIG TIME UPPER SUPPORT FOR LIFT...PRECIPITATION
SHOULD BE AT ITS MAXIMUM COVERAGE AND INTENSITY DURING THE DAY
MONDAY AND AT LEAST EARLY MONDAY EVENING...IF NOT MUCH OF IT.
MIXING RATIOS OF 6-8 G/KG SHOULD SUPPORT MODEST IF NOT TEMPORARILY
HEAVY RATES...AND OBVIOUSLY THATS WHERE CONCERNS ARE REALLY
HEIGHTENED WITH ANY FREEZING RAIN.
GIVEN THE QUICK UPTICK IN INTENSITY OF RAINFALL AND EASTERLY
SURFACE WINDS...HAVE CONTINUED TO KEEP TEMPERATURES SLOW TO WARM
DURING THE DAY. TEMPERATURES STILL SHOULD BE INCHING UP TO OR EVEN
ABOVE FREEZING FROM SOUTH TO NORTH ACROSS THE AREA...BUT THAT
LOOKS LIKE IT WILL LAG THE ONSET OF MODERATE PRECIPITATION AND
THUS CONTINUE WITH FORECAST ICE ACCUMULATION IN THE CWA...NAMELY
THE NORTHERN HALF AWAY FROM THE IMMEDIATE LAKE. FOR AREAS ADJACENT
TO LAKE MICHIGAN...INCLUDING DOWNTOWN CHICAGO...STIFF ONSHORE FLOW
GUSTING TO 40 MPH PLUS /ESPECIALLY NEAR THE LAKE SHORE/ SHOULD
KEEP TEMPERATURES JUST ABOVE FREEZING. TEMPERATURES DO NOT LOOK TO
BE SIGNIFICANTLY BELOW FREEZING WHERE THEY ARE SUB 32...WHICH IS
ONE THING THAT COULD HELP EASE IMPACTS. IF HOWEVER ICE ACCRETION
DOES BEGIN ON LIMBS OR POWER LINES AND OVER SEVERAL HOURS...THE
STRONG WINDS COULD ALLOW FOR HIGHER IMPACTS.
AGAIN IN SUMMARY...THINGS GOING FOR THIS EVENT ARE A STIFF EAST WIND
AND A WIDESPREAD PRECIPITATION SHIELD TO KEEP THE SURFACE
TEMPERATURES FROM WARMING RAPIDLY...OR AT LEAST MORE RAPIDLY THAN
EVEN THE WARMEST GUIDANCE...AND THUS ALLOW FOR WHAT APPEARS TO BE
SEVERAL HOUR DURATION OF FREEZING RAIN. MOST CONCERNED FOR NORTH
CENTRAL ILLINOIS...INCLUDING ROCKFORD...WHERE COLLABORATED ICE
FORECASTS WITH WPC AND ADJACENT WFOS IS PRESENTLY AT OR ABOVE 0.20
OF AN INCH.
TUESDAY STILL LOOKS TO OFFER SOME SNOW POSSIBILITY ON THE
BACKSIDE OF THE SYSTEM...THOUGH WITH IT FILLING AM NOT EXPECTING A
WELL- DEFINED DEFORMATION/WRAPAROUND AS FAR EAST AS THE CWA.
TEMPERATURES LOOK TO EASE DOWN THROUGH THE WEEK INTO UNFAMILIAR
TERRITORY OF BELOW NORMAL BY THE START TO 2016. THERE CONTINUES
TO BE A CHANCE OF SNOW ON WEDNESDAY BUT HAVE GONE WITH A WELL-
VERIFYING MODEL BLEND AT THIS TIME TO FOCUS ON THE PREVIOUS
SYSTEMS.
MTF
&&
.HYDROLOGY...
RAIN DEVELOPING ALONG A STATIONARY FRONT DURING THE DAY
TODAY...AND POSSIBLY HEAVY AT TIMES LATE THIS AFTERNOON TONIGHT...IS
LIKELY TO PERSIST THROUGH EARLY SUNDAY MORNING. THUNDERSTORMS
ALSO ARE POSSIBLE ACROSS SOUTHERN PORTIONS OF THE AREA MAINLY
SOUTH OF THE KANKAKEE RIVER...WHERE WIDESPREAD 1.5 TO 2 INCH
RAINFALL AMOUNTS ARE MOST LIKELY. LOCALIZED AMOUNTS IN EXCESS OF 3
INCHES REMAIN POSSIBLE...THOUGH AT THIS TIME THIS MAY OCCUR JUST
SOUTH OF THE LOCAL AREA. REGARDLESS...THESE RAINFALL AMOUNTS MAY
RESULT IN SIGNIFICANT RISES AND POSSIBLE FLOODING ALONG AREA
RIVERS AND STREAMS...INCLUDING THE IROQUOIS AND KANKAKEE RIVERS AS
WELL AS SUGAR CREEK. IN ADDITION...THE HEAVY RAIN WILL LIKELY
RESULT IN SOME PONDING OF WATER IN LOW LYING AND POOR DRAINAGE
AREAS. SEE THE CURRENT FFALOT FOR MORE DETAILS. THIS APPEARS TO BE
MORE OF A FLOODING SITUATION THAN A TRUE FLASH FLOOD
SITUATION...BUT GIVEN THE CONVECTIVE ELEMENT TO THE PRECIPITATION
AND THE EFFICIENCY OF THE PRECIPITATION EXPECTED TONIGHT AND
SATURATED GROUND...FLOODING COULD OCCUR QUICKLY FOR AREAS STUCK
UNDER HEAVY RAINFALL. THE FLOOD WATCH FOR OUR SOUTHERN COUNTIES WILL
ALSO ACCOUNT FOR ANOTHER 1-1.5 INCHES OF RAINFALL EXPECTED ON
MONDAY.
KMD
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* RA/SHRA DEVELOP LATER THIS MORNING...LIKELY TAPER TO DZ
LATE...WITH ANOTHER POSSIBLE PERIOD OF -RA OVERNIGHT.
* VERY SLIGHT CHANCE EMBEDDED TS WITH THE -SHRA TODAY.
* MVFR CIGS QUICKLY DROPPING TO IFR/LIFR LATE THIS MORNING WITH
FOG POSSIBLE.
* EAST WINDS GUSTING TO AROUND 20 KT THIS MORNING. EAST WINDS
REMAIN ABOVE 10 KT THROUGH MID AFTERNOON THEN SHIFT NNE AND
INCREASING AGAIN LATE TONIGHT.
KREIN
//DISCUSSION...UPDATED 12Z...
LOW CLOUDS CONTINUE TO SPREAD NORTH OF WARM FRONTAL BOUNDARY
DRAPED WELL SOUTH OF THE AREA. UPSTREAM OBS SUGGEST A BRIEF PERIOD
OF MVFR FOLLOWED BY A CONTINUED DETERIORATION TO IFR AND THEN LIFR
THROUGH THE MORNING AND EARLY AFTERNOON. MEAWNWHILE...EAST WINDS
ARE RAMPING UP AS HIGH PRESSURE DEPARTS EAST AND A LOW LEVEL
TROUGH AXIS SHIFTS NORTH AND EAST. THE CENTER OF LOW PRESSURE WILL
PASS SOUTH OF THE TERMINALS THIS EVENING AND EAST
OVERNIGHT...RESULTING IN A SHIFT TO NORTH WINDS WITH AN INCREASE
IN INTENSITY AS STRONG HIGH PRESSURE BUILDS SOUTH FROM CANADA.
REGARDING PRECIPITATION...SEVERAL WAVES ARE EXPECTED. THE FIRST
BEING LATER THIS MORNING/EARLY AFTERNOON AS WARM/MOIST ADVECTION
INCREASES. THE AREA OF SHOWERS AND THUNDERSTORMS LOOKS OVER
MISSOURI APPEARS TO BE THE FIRST WAVE...BUT LOW CONFIDENCE ON TS
OCCURRENCE AT THE TERMINALS. LAPSE RATES ALOFT ARE ELEVATED ENOUGH
TO SUPPORT IT SO CERTAINLY A POSSIBILITY BUT NOT IN THE TAF AT THE
MOMENT. CIGS THEN STAY DOWN MOST OF THE NIGHT AND LIKELY SOME
VSBY REDUCTIONS AS WELL. FEEL PRETTY CONFIDENT THAT THERE WILL BE
A PERIOD OF 1SM VSBY REDUCTIONS...WITH SOME GUIDANCE HINTING A BIT
LOWER...SO THIS WILL BEAR MONITORING. ADDITIONAL BOUTS OF MODERATE
TO HEAVY RAINFALL ARE EXPECTED THIS EVENING AS THE LOW LEVEL
THERMAL ZONE STRENGHTENS...WITH THE AXIS SHIFTING SOUTHEAST AS THE
NIGHT GOES ON. GUSTY NE WINDS PERSIST INTO SUNDAY MORNING WITH
SOME SLIGHT LIFTING TO CIGS.
KMD
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* MEDIUM CONFIDENCE IN PRECIP TRENDS TODAY.
* LOW CONFIDENCE IN TS OCCURRENCE AT THE TERMINALS.
* HIGH CONFIDENCE IN CIGS DROPPING TO IFR/LIFR...MEDIUM CONFIDENCE
IN TIMING OF IFR CIGS +/- A COUPLE HOURS.
* LOW CONFIDENCE IN HOW LOW VSBY WILL DROP IN FOG TODAY.
* MEDIUM-HIGH CONFIDENCE IN WIND TRENDS.
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT...WINTRY MIX POSSIBLE LATE. MVFR CIGS PSBL.
MONDAY...WINTRY MIX TURNING TO RAIN. MVFR CIGS AND VSBYS.
TUESDAY...MVFR CIGS. CHANCE OF -SN/RA IN THE MORNING.
WEDNESDAY...MVFR CIGS. CHANCE OF -SN.
THURSDAY...MVFR CIGS.
FRIDAY...DRY. VFR.
KMD
&&
.MARINE...
456 AM CST
.HIGH PRESSURE OVER THE NORTHERN LAKES WILL QUICKLY MOVE EAST
TODAY...WHILE LOW PRESSURE DEVELOPS OVER THE SOUTHERN PLAINS. THIS
LOW WILL MOVE QUICKLY NORTHEAST ACROSS THE MIDWEST THIS AFTERNOON
AND INTO NEW ENGLAND BY EARLY SUNDAY. EXPECT WINDS TO RAMP UP
BETWEEN THESE TWO FEATURES RESULTING IN SOME HIGHER WAVES ALONG
THE ILLINOIS SIDE TODAY. STRONG HIGH PRESSURE OVER THE UPPER
MIDWEST EXTENDING INTO SOUTHERN MANITOBA WILL BUILD EAST ACROSS
ONTARIO LATE IN THE WEEKEND...WHILE ANOTHER DEEP LOW DEVELOPS
ACROSS TEXAS. AHEAD OF THE STRONG HIGH...A SURGE OF NORTH WINDS TO
30 KT...POSSIBLY A FEW GALE GUSTS...WILL OCCUR LATE TONIGHT INTO
SUNDAY.
THIS SECOND LOW WILL THEN DEEPEN OVER THE LOWER MISSOURI VALLEY
MONDAY MORNING...THEN WILL LIFT NORTHEAST ACROSS WESTERN GREAT
LAKES BY EARLY TUESDAY BEFORE FILLING. THE GRADIENT BETWEEN THIS
LOW AND THE VERY STRONG HIGH WHICH ONLY SLOWLY MOVES EAST WILL
RESULT IN A PERIOD OF STRONG GALES MONDAY...POSSIBLY WITH A FEW
STORM FORCE WIND GUSTS ALONG WITH COASTAL FLOODING ISSUES ALONG
THE ILLINOIS NEARSHORE. ANOTHER WEAK LOW WILL MOVE OVER THE
NORTHERN HALF OF THE LAKE WEDNESDAY FOLLOWED BY COOL HIGH
PRESSURE.
KMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLASH FLOOD WATCH...ILZ033-ILZ039...6 PM SATURDAY TO 6 PM MONDAY.
IN...FLASH FLOOD WATCH...INZ010-INZ011-INZ019...6 PM SATURDAY TO 6 PM
MONDAY.
LM...SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 6 PM SATURDAY.
&&
$$
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AREA FORECAST DISCUSSION
National Weather Service Lincoln IL
1101 PM CST FRI DEC 25 2015
.UPDATE...
ISSUED AT 845 PM CST FRI DEC 25 2015
Surface high pressure located well north of our area will shift
slowly east overnight while high and mid level clouds increase
from the southwest ahead of our next weather system. Thunderstorms
that were occurring today along a stalled frontal boundary over
the southern Mississippi Valley have kept that boundary further
south than indicated by models yesterday at this time. Just what
affect, if any, that will have on the placement of the front
in southeast Illinois tomorrow remains to be seen, and that will
be the key to where the heavy rainfall sets up as a plume of deep
subtropical moisture, seen on our evening water vapor loop, streams
northeast into the region on Saturday into Saturday night. The 00z
ILX sounding showing quite a bit of dry air in place in the low
and mid levels of the atmosphere. The latest RAP model suggests
any rain on Saturday will hold off until dawn across southeast
Illinois, and over the remainder of our area by late morning.
Temperatures early this evening have dropped off quicker than
earlier thought so we had to make some adjustments to the overnight
lows. Based on the latest satellite trends, it appears with the
thicker cloud cover moving up from the southwest, we may have seen
our overnight lows reached in some areas already with a steady or
slowly rising trend late tonight. Should have the updated zones
out by 900 pm.
&&
.SHORT TERM...(Tonight)
ISSUED AT 333 PM CST FRI DEC 25 2015
Early afternoon surface map showing high pressure centered over
Wisconsin, providing a dry north/northeast flow into central
Illinois. Expansive area of stratus has extended southwest from the
high and did clip the far western CWA earlier this morning, but the
southern and eastern edges have eroded some. However, there has been
some diurnal type development a bit further to the south. Most of
the forecast area has had a fairly nice day, with temperatures
reaching the mid 40s to lower 50s with a good deal of sunshine. The
far northwest corner was still below 40 degrees early this afternoon
due to the more extensive clouds.
Main focus for tonight will be with the timing of precipitation.
There has been quite a bit of convection this afternoon from
Louisiana northeast into eastern Tennessee, which is slowing the
northward push of the frontal boundary. Most of the morning models
generally bring the front into the southern tip of Illinois by
morning, as the southwest upper flow begins to sharpen with an upper
low forms over Arizona. Have maintained the chance PoP`s across the
far southeast CWA, as forecast soundings near Lawrenceville show a
nice moistening of the lower layers between midnight and 3 am. Areas
further north do not see this happening until closer to morning, so
have kept the forecast dry from about Rushville-Mattoon northward.
Temperatures will be relatively steady through the night.
.LONG TERM...(Saturday through Friday)
ISSUED AT 333 PM CST FRI DEC 25 2015
Several weather concerns over the next few days for central IL:
First, A major rain event continues to set up for central/SE IL and
surrounding areas. Two periods of heaviest rainfall appear likely at
this point. First will start Saturday morning south of I-70, spread
northward through the early afternoon encompassing much of the I-72
corridor, and continue into Sunday morning. A lull Sunday afternoon-
evening...then re-intensification Sunday night through Monday
afternoon. A flash flood watch is in effect from Saturday at noon to
Monday evening for areas from Scott County through Springfield to
Champaign county and areas south/eastward.
Second, thunderstorms with some severe potential Saturday afternoon
through Saturday night...mainly southeast of a Springfield to
Champaign line.
Third, potential for freezing rain Sunday night/Monday
morning...mainly north of I-72.
Synopsis...A frontal boundary will start the day near or south of
the Ohio River Saturday morning...lifting northward rapidly through
the day as strong southwesterly flow sets up ahead of a deepening
upper low over the Southwestern states. A plume of near 1.5 inch
precipitable water (near record for this time of year) will be
interacting with the warm frontal zone creating a plume of heavy
rain through central IL. Rainfall amounts of 2 to 3 inches can be
expected Saturday afternoon through Sunday morning from around
Springfield to Champaign southward through Flora and Lawrenceville.
Enough instability is indicated by model solutions for thunderstorms
in this area as well, and there will be enough shear for a concern
of severe storms...however instability is somewhat on the weak side.
The next feature will be a vigorous low ejecting out of the
Southwestern states...providing widespread lift by Sunday night and
another round of heavy precipitation...this time another 2 inches
across central IL. All told...4 to 6 inches possible I-72
southward...with 2 to 4 inches to the north by Tuesday morning.
The low track has trended somewhat northwest of previous runs at
this point...which diminishes the freezing rain and snow threat
somewhat through central IL For Monday/Monday night. Latest trends
would suggest freezing rain will be limited more toward areas north
of I-72 than previous runs as cold air would be confined to areas
farther northwest.
Temps will edge above freezing everywhere toward midday Monday,
resulting in a change over to all rain. Once the low tracks into
the southern Great Lakes, enough cold air will be pulled down behind
it to support a change over to snow or a rain/snow mix north of I-70
Monday night. Will need to keep an eye on this, as any eastward
deviation of the low track will lead to more snow and possible
accumulations across the area.
A break in precipitation is expected Wednesday, then another system
could bring some light precipitation...mainly snow...back late
wednesday into Wednesday night.
Temperatures quite mild Saturday with highs ranging from 46 in
Galesburg to 64 in Lawrencevile...then following a cooling trend
through midweek. Eventually...Highs should be near or slightly below
normal with highs ranging from the upper 20s to upper 30s by
Thursday.
&&
.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
ISSUED AT 1100 PM CST FRI DEC 25 2015
Timing of MVFR/IFR clouds and rain into the forecast area is the
main forecast concern this period. Once the rain and low cigs
arrive, they will be here thru Saturday night/Sunday morning.
Currently, the MVFR cigs were located south of I-70 but were
tracking to the north at 15-20 kts. Based on the present
movement, it appears the MVFR cigs will arrive at SPI and DEC
around 09z, CMI by 10z, BMI and PIA by 11-12z. The rain will
follow during the morning hours which will effectively moisten
the lower layers resulting in IFR/LIFR cigs by late morning
or early afternoon. Surface winds will continue from an easterly
direction at 10 to 15 kts overnight and turn more into a
southeast direction on Saturday at 10 to 15 kts before winds
back more into a northeast direction at 8 to 15 kts in the
01z-04z time frame.
&&
.ILX Watches/Warnings/Advisories...
Flash Flood Watch from Saturday afternoon through Monday
afternoon for ILZ044>046-049>057-061>063-066>068-071>073.
&&
$$
UPDATE...Smith
SHORT TERM...Geelhart
LONG TERM...Onton
AVIATION...Smith
AREA FORECAST DISCUSSION
NWS JACKSON KY
931 PM EST SUN DEC 27 2015
.UPDATE...
ISSUED AT 931 PM EST SUN DEC 27 2015
FORECAST IS IN DECENT SHAPE THIS EVENING. SHOWER ACTIVITY HAS
BEEN PICKING UP ACROSS THE SOUTH ALONG THE SFC FRONTAL BOUNDARY AS
IT CONTINUES TO EDGE CLOSER...BUT MORE SLOWLY TOWARDS THE KY/TN
STATE LINE. SEEING EVIDENCE THAT SOUTHERLY LOW LEVEL FLOW MAY
ALREADY BE STRENGTHENING TO OUR WEST ACROSS WESTERN/CNTRL KY...
HINTING AT THE POSSIBILITY OF SOME REDEVELOPMENT OF SHOWER
ACTIVITY THROUGH THE PREDAWN HOURS OVER OUR WESTERN MOST COUNTIES.
THIS FACTOR WOULD ALSO EXPLAIN THE PERSISTENT YET LIGHT NATURE OF
ACTIVITY ACROSS OUR NORTH...ATTM A BIT MORE THAN EXPECTED EARLIER
THIS EVENING. MOST RECENT HRRR SUPPORTS CURRENT LINE OF THINKING
AS WELL. HAVE MADE SOME MINOR ADJUSTMENTS TO THE GRIDS AND
FORECAST PACKAGE FOR LATEST THOUGHTS AND HOURLY TRENDS.
UPDATE ISSUED AT 545 PM EST SUN DEC 27 2015
A FRONTAL BOUNDARY IS CURRENTLY DROPPING SOUTHWARD THROUGH OUR
FORECAST AREA AND IS EXPECTED TO MOVE SOUTH OF THE HAL ROGERS
PARKWAY/HWY 80 BY EARLY MORNING MONDAY...06-09Z. HOWEVER...WE ARE
LOSING MOST OF THE FORCING ALONG THIS BOUNDARY AS H925-H850 WINDS
WEAKEN FROM AROUND 45 KTS TO LESS THAN 15 KTS THROUGH THE EVENING
HOURS. THEREFORE EXPECT BAND OF RAINFALL TO OUR NORTH TO DIMINISH
WITH TIME AS LLJ WEAKENS. THERE IS ENOUGH CONVERGENCE ALONG THE
BOUNDARY ITSELF HOWEVER TO ALLOW SCATTERED SHOWERS TO DEVELOP
ALONG THE FRONT AS IT PUSHES SOUTHWARD. LLJ STRENGTHENS AGAIN
TOWARDS DAWN WHICH WILL BE RESPONSIBLE FOR REDEVELOPMENT OF
CONVECTION MOVING IN FROM THE WEST...SOUTHWEST. SHORT TERM MODELS
HAVE PICKED UP WELL ON THIS SCENARIO...AND CURRENT RADAR TRENDS
ESPECIALLY SUPPORTS THIS LINE OF THINKING FOR THE IMMEDIATE SHORT
TERM PERIOD. HAVE ADJUSTED GRIDS AND ZONES ACCORDINGLY.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 215 PM EST SUN DEC 27 2015
18Z SFC ANALYSIS SHOWS THE INITIAL LOW PRESSURE WAVE PASSING OUT
OF KENTUCKY. THIS IS DRAGGING THE FRONT OUR WAY FROM THE WEST AND
NORTH. SO FAR...THOUGH...THE CONVECTION ASSOCIATED WITH THIS
BOUNDARY FOR EAST KENTUCKY HAS MAINLY JUST BEEN SOME SCATTERED
LIGHT SHOWERS AFFECTING LOCATIONS NORTH OF INTERSTATE 64. FOR THE
MOST PART OUR AREA ENJOYED A VERY WARM AND BREEZY DAY WITH
TEMPERATURES PEAKING IN THE MID 70S. DEW POINTS WERE QUITE
SUMMER- LIKE IN THE UPPER 50S AND LOWER 60S FOR MOST PLACES. WINDS
GUSTED TO BETWEEN 20 AND 25 MPH FROM THE SOUTHWEST FOR LOCATIONS
THAT SAW ANY SUNSHINE FROM BETWEEN BROKEN DECKS OF MID AND HIGH
LAYER CLOUDS. THE RIVERS THROUGH EAST KENTUCKY CONTINUE TO RUN
HIGH BUT ARE ALL DROPPING.
THE MODELS ARE IN GOOD AGREEMENT ALOFT AS THEY ALL ROLL A VERY
STRONG...AND FAR SOUTH...CLOSED LOW FROM THE BIG BEND REGION OF
TEXAS NORTH NORTHEAST INTO THE UPPER MIDWEST AND EVENTUALLY TO THE
WESTERN GREAT LAKES BY TUESDAY MORNING. THE MODELS CLUSTER BETTER
WITH THIS LOW/S TRACK AND STRENGTH THAN THEY DID 24 HOURS AGO.
ACCORDINGLY...CONFIDENCE HAS INCREASED IN THEIR CONSENSUS
SOLUTION. FOR EAST KENTUCKY...WE WILL ENDURE A GLANCING BLOW FROM
THIS SYSTEM WITH ITS MAIN EFFECTS PASSING THROUGH LATER MONDAY
INTO EARLY TUESDAY MORNING AS ITS VORT STREAM CROSSES KENTUCKY.
OTHERWISE...BROAD AND DEEP SOUTHWEST FLOW WILL BE THE RULE INTO
MONDAY AFTERNOON SUSTAINING THE WARM AND MOIST CONDITIONS. GIVEN
THE BETTER MODEL AGREEMENT HAVE FAVORED A BLENDED SOLUTION WITH
EMPHASIS ON THE NAM12 FOR WEATHER DETAILS AND THE HRRR...WITH A
GRAIN OF SALT...IN THE NEAR TERM.
SENSIBLE WEATHER WILL FEATURE A WARM EVENING FOR MOST OF THE AREA
BUT A COOLING AND WETTER ONE IN THE NORTH AND WEST AS THAT
FRONT/S IMPACTS ARE FELT. IN TIME...TONIGHT...THIS BOUNDARY WILL
BRING COOLER CONDITIONS DEEPER INTO EAST KENTUCKY ALONG WITH
SCATTERED TO NUMEROUS SHOWERS. CANNOT RULE OUT A STRAY
THUNDERSTORM DURING THE NIGHT...BUT CHANCES ARE PRETTY SMALL. FOR
MONDAY...ADDITIONAL SHOWERS AND PERHAPS A THUNDERSTORM WILL BE
AROUND INTO THE AFTERNOON OUT AHEAD OF AN APPROACHING AND MUCH
STRONGER COLD FRONT. THIS FRONT WILL BRING THE BULK OF THE RAIN
EXPECTED ACROSS EAST KENTUCKY FOR THIS PERIOD...MAINLY IN THE
EVENING MONDAY AND THE OVERNIGHT HOURS INTO EARLY TUESDAY. AT
THAT POINT THE WHOLE WEATHER SYSTEM WILL BE PROGRESSIVE ENOUGH TO
LIKELY PRECLUDE ANY MORE THAN JUST SOME BRIEF NUISANCE FLOODING.
AS SUCH...WILL HOLD OFF ON ANY FLOOD WATCHES FOR THE TIME BEING.
SHOULD THE SHOWER ACTIVITY BECOME MORE ROBUST TONIGHT OR INTO THE
DAY MONDAY CONDITIONS WOULD THEN BE MORE RIPE FOR FLOODING AND A
WATCH MAY BE NEEDED. FOR NOW WILL CONTINUE THE CURRENT ESF
DETAILING THE RAINFALL CONCERNS THROUGH TUESDAY. WARM TEMPERATURES
WILL CONTINUE FOR MOST OF THE AREA ON MONDAY AHEAD OF THE MAIN
COLD FRONT WITH DAILY RECORDS THREATENED AGAIN.
AGAIN STARTED WITH THE SHORTBLEND FOR TEMPERATURES AND DEW POINTS
THROUGH MONDAY MORNING AND THE SUPERBLEND THEREAFTER THROUGH
MONDAY NIGHT. DID HAVE TO ADJUST THESE IN THE NEAR TERM TO
CAPTURE THE CURRENT WARMTH FOR MOST OF THE AREA. ALSO MADE SOME
MINOR CHANGES TO THE LOWS OVER OUR SOUTHERN COUNTIES TONIGHT WHERE
A SMALL RIDGE AND VALLEY DIFFERENCE IS EXPECTED TO SET UP IN THE
EVENING BEFORE THE THICKER AND LOWER CLOUDS MOVE IN...ALONG WITH
THE HIGHER PCPN CHANGES. AS FOR POPS...ENDED UP MOST SIMILAR TO
THE MET NUMBERS...BUT NOT TOO FAR FROM THE MAV/S THROUGH THE
PERIOD.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 306 PM EST SUN DEC 27 2015
THE MODELS WERE IN GOOD AGREEMENT IN THE LONG TERM THIS TIME AROUND.
THE CONSENSUS IS FOR A LARGE WELL DEVELOPED AREA OF LOW PRESSURE TO
MOVE QUICKLY ACROSS THE GREAT LAKES REGION AND INTO NE ENGLAND
TUESDAY AND TUESDAY NIGHT. THE LOW WILL DRAG A SURFACE COLD FRONT
EASTWARD ACROSS EASTERN KENTUCKY ON TUESDAY. SCATTERED RAIN SHOWERS
ARE EXPECTED TO MOVE ACROSS THE AREA AS WELL JUST BEHIND THE
DEPARTING FRONTAL BOUNDARY. AFTER A VERY BRIEF LULL...ANOTHER
WEATHER SYSTEM IS EXPECTED TO APPROACH FROM THE SOUTHWEST AND MOVE
UP THE SPINE OF THE APPALACHIAN MOUNTAINS TUESDAY NIGHT AND
WEDNESDAY. THIS SECOND WEATHER SYSTEM SHOULD BRING SCATTERED TO
NUMEROUS RAIN SHOWERS TO THE AREA THROUGH THE MIDDLE OF THE WEEK.
THE QUESTION WILL BE THE AMOUNT OF MOISTURE AVAILABLE TO THE SYSTEM
AS IT MOVES THROUGH. AT THIS TIME BASED ON THE MODEL AGREEMENT...IT
SEEMED REASONABLE TO HAVE FAIRLY HIGH POPS IN THE FORECAST FOR
TUESDAY NIGHT AND WEDNESDAY. TEMPERATURES WILL REMAIN WARM ENOUGH TO
KEEP EVERYTHING IN LIQUID FORM. ONCE THIS SECOND SYSTEM EXITS THE
AREA ON WEDNESDAY MORNING...THE REST OF THE WEEK SHOULD BE DRY AND
MUCH COOLER THAN WE HAVE BEEN USED TO IN RECENT WEEKS.
TEMPERATURES WILL BE WELL ABOVE NORMAL TUESDAY AND WEDNESDAY...AS AN
UNSEASONABLY WARM AND MOIST AIR MASS REMAINS IN PLACE ACROSS THE
REGION. WE CAN EXPECT MUCH COOLER TEMPERATURES ON THURSDAY AS COLD
AIR SPILLS INTO THE AREA BEHIND A DEPARTING AREA OF LOW PRESSURE. A
MAJOR COOL DOWN WILL THEN BE ON TAP FOR FRIDAY AND SATURDAY...AS A
CANADIAN AS MASS SETTLES OVER THE REGION. HIGHS TO END THE WEEK AND
INTO THE UPCOMING WEEKEND WILL LIKELY BE SEVERAL DEGREES COOLER THAN
NORMAL ACROSS EASTERN KENTUCKY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 740 PM EST SUN DEC 27 2015
A FRONTAL BOUNDARY IS CURRENTLY DROPPING SOUTHWARD THROUGH OUR
FORECAST AREA AND IS EXPECTED TO MOVE WELL SOUTH OF THE HAL
ROGERS PARKWAY/HWY 80 BY EARLY MORNING MONDAY...06-09Z. NUMEROUS
RAIN SHOWERS NORTH OF THE SFC FRONT ARE GRADUALLY DIMINISHING IN
COVERAGE AND INTENSITY AS SUPPORT FOR ACTIVITY WANES. OTHERWISE...
ISOLD TO SCATTERED SHOWERS CONTINUE TO DEVELOP ALONG THE BOUNDARY
AND WILL CONTINUE TO DO SO THROUGH THE OVERNIGHT...THOUGH THERE
WILL BE A DOWNWARD TREND IN OVERALL ACTIVITY. MAIN AVIATION
CONCERN WILL BE THE LOWER CIGS JUST BEHIND THE FRONTAL
BOUNDARY...GENERALLY IFR LEVELS WHILE VFR CIGS EXIST SOUTH OF THE
SFC BOUNDARY. PILOTS COULD EXPERIENCE SOME DIRECTIONAL SHEAR ALOFT
AND ALONG THE LOCATION OF THE SFC BOUNDARY AS WELL. NORTHERLY
WINDS A BIT STRONGER NORTH OF THE FRONT...WITH BRIEF GUSTS TO
AROUND 20 KTS JUST ALONG THE FRONT WILL PUSH THE LOWER CIGS
SOUTHWARD THROUGH THE OVERNIGHT. WINDS WILL THEN CONTINUE TO
VEER...EVENTUALLY BECOMING MORE SOUTHERLY THROUGH THE DAY TOMORROW
AS THE SFC BOUNDARY LIFTS BACK TO THE NORTH AND CIGS RISE BACK UP
INTO MVFR/VFR TERRITORY. WINDS WILL ALSO GUST TO BETWEEN 15 AND 20
KTS AT TIMES.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
UPDATE...RAY
SHORT TERM...GREIF
LONG TERM...AR
AVIATION...RAY
AREA FORECAST DISCUSSION
NWS JACKSON KY
358 PM EST SAT DEC 26 2015
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 300 PM EST SAT DEC 26 2015
19Z SFC ANALYSIS SHOWS DEEP LOW PRESSURE OFF TO THE SOUTHWEST OF
THE AREA WITH A WARM FRONT NOW LIFTING INTO AND THOUGH KENTUCKY.
SOME HEALTHY SHOWERS AND A FEW THUNDERSTORMS ARE BEING PUSHED
NORTH THROUGH THE AREA AHEAD OF THIS BOUNDARY. THE STRONGER
PORTIONS OF THIS CLUSTER IS FOUND JUST TO THE WEST OF THE JKL
CWA...BUT THE ENTIRE AREA IS PROGRESSIVE ENOUGH TO LIMIT ANY
RENEWED FLOODING CONCERNS FOR NORTHERN PARTS OF OUR AREA OF
RESPONSIBILITY. FOR THE SOUTHEAST PART OF EASTERN KENTUCKY THE
CLOUDS ARE SCATTERING OUT ALLOWING FOR MORE SUNSHINE WHILE THE
NORTHWEST REMAINS FAIRLY CLOUDY. THIS IS HAVING AN EFFECT ON
TEMPERATURES ACROSS WITH THE SOUTHEAST REACHING NEAR 70 DEGREES
WHILE THE NORTHWEST STILL HAS A FEW LOCATIONS IN THE UPPER 50S.
JKL HAS ALREADY SMASHED ITS RECORD HIGH FOR THE DAY...BUT LOZ MAY
NEED SOME GOOD CLOUD BREAKS TO EXCEED ITS RECORD. DEWPOINTS ALSO
VARY FROM SOUTHEAST TO NORTHWEST WITH LOWER 60S CLOSER TO
TENNESSEE AND VIRGINIA WHILE MID 50S ARE FOUND NORTH OF INTERSTATE
64. WINDS...MEANWHILE...ARE GENERALLY LIGHT FROM THE SOUTH TO
SOUTHEAST.
THE MODELS ARE IN GOOD AGREEMENT ALOFT THROUGH THE SHORT TERM.
THEY ALL DEPICT THE ANOMALOUSLY DEEP TROUGH CLOSING OFF ABOVE
NORTHERN MEXICO THIS EVENING HELPING TO PUMP THE SOUTHEAST RIDGE
DOWNSTREAM OVER KENTUCKY. ON SUNDAY...THE MODELS ROLL THIS UPPER
LOW INTO CENTRAL TEXAS WITH THE NAM SLIGHTLY STRONGER AND FURTHER
NORTH THAN THE GFS AND LATEST ECMWF. FOR KENTUCKY THIS YIELDS
HEIGHTS A SMIDGE HIGHER HEADING INTO SUNDAY NIGHT. THE GFS IS MORE
PROGRESSIVE WITH THE UPPER LOW INTO MONDAY MORNING WHILE THE ECMWF
AND NAM ARE IN BETTER AGREEMENT WITH A SLOWER MOVEMENT....REACHING
SOUTH CENTRAL OKLAHOMA BY 12Z VERSUS THE GFS POSITION OF THE LOW
CROSSING INTO ARKANSAS. HEIGHT DIFFERENCES REMAIN FOR EASTERN
KENTUCKY DOWNSTREAM WITH THE NAM/ECMWF ABOUT 30 DECAMETERS HIGHER
THAN THE GFS SOLUTION. THE BETTER AGREEMENT BETWEEN THE MORE
CONSISTENT ECMWF AND NAM LEND SUPPORT TO FAVORING THE NAM12 ON WX
DETAILS FOR THE SHORT TERM...IN CONJUNCTION WITH THE HRRR EARLY
ON.
SENSIBLE WEATHER WILL FEATURE THE MAJORITY OF ANY PCPN LIFTING
NORTH OF THE AREA BY EVENING WITH JUST A FEW STRAY SHOWERS
POSSIBLE INTO THE NIGHT...MAINLY CONFINED TO THE NORTHERN PARTS OF
THE AREA. GIVEN THE POSITION OF THE PCPN AND THICKER CLOUDS...
EXPECT A SMALL TO MODERATE RIDGE AND VALLEY SPLIT TO DEVELOP FOR
AT LEAST THE SOUTHERN 2/3RDS OF THE CWA. PATCHY VALLEY FOG WILL
ALSO BE POSSIBLE IN PLACES THAT HAVE THE THINNEST CLOUDS. FOR
SUNDAY...OUR WARMEST TEMPERATURES EVER RECORDED FOR DECEMBER
COULD BE THREATENED...DEPENDING ON THE QUALITY OF THE SUNSHINE
SEEN. HIGHS SHOULD EASILY BE IN THE MID 70S WITH UPPER 70S
POSSIBLE. DECEMBER/S RECORD HIGH FOR JKL IS 79 AND LOZ IS 78...
CERTAINLY WITHIN THE REALM OF POSSIBILITIES. ANY CONVECTION IN
THE WARM SECTOR SOUTH OF THE FRONT...LYING NORTH OF THE OHIO
RIVER...COULD END UP AS A THUNDERSTORM PARTICULARLY FOR LOCATIONS
NORTH OF THE MOUNTAIN PARKWAY. FOR SUNDAY AFTERNOON AND EVENING...
THE FRONT WILL START TO SHIFT SOUTH IN RESPONSE TO THE DEVELOPING
SFC LOW TO THE WEST. THIS WILL BRING A THREAT OF CONVECTION AND
HEAVY/TRAINING RAINS BACK INTO AT LEAST THE NORTHERN PARTS OF THE
AREA. THAT NIGHT THE CONVECTION WITH THE FRONT SHOULD WEAKEN AS
THE LOW APPROACHES WITH A STRIATION TO LOW TEMPERATURES DUE TO THE
WAGGLE OF THE BOUNDARY WITH SOME UPPER 40S POSSIBLE NORTH WHILE
THE SOUTH SETTLES INTO THE MID AND UPPER 50S.
FOR TEMPERATURES AND DEWPOINTS...AGAIN STARTED WITH THE SHORTBLEND
GUIDANCE THROUGH SUNDAY MORNING AND THEN THE SUPERBLEND INTO
MONDAY MORNING. MADE MORE SIGNIFICANT CHANGES TO THE LOWS TONIGHT
WITH A BETTER CHANCE FOR A RIDGE AND VALLEY DISTINCTION THROUGH
THE NIGHT FOR MUCH OF THE AREA. AS FOR POPS...ENDED UP CLOSER TO
THE WETTER MET NUMBERS FOR SUNDAY AND SUNDAY NIGHT.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 358 PM EST SAT DEC 26 2015
THE MODELS ARE IN GOOD AGREEMENT THROUGH THE PERIOD...WITH AN
AMPLIFIED PATTERN TO CONTINUE. A DEEP CUT OFF LOW WILL START OUT
ON MONDAY DOWN IN THE ARKLATEX REGION. THIS WILL SWING NORTHEAST
INTO THE GREAT LAKES BY MONDAY NIGHT...WITH ANOTHER SHORT WAVE
TROUGH DIGGING ACROSS THE DESERT SOUTHWEST AND THEN LIFTING
NORTHEAST ACROSS THE PLAINS AND EVENTUALLY THROUGH THE OHIO VALLEY
BY MID-WEEK. THE NORTHERN STREAM FINALLY MAKES A COMEBACK ACROSS
THE OHIO/TENNESSEE VALLEYS TOWARDS THE NEW YEAR...FINALLY BREAKING
THE WAY ABOVE NORMAL READINGS WE HAVE BEEN SEEING FOR THE PAST 1
TO 2 WEEKS.
A SURFACE COLD FRONT WILL BE SWINGING THROUGH EASTERN KENTUCKY
LATE IN THE DAY ON MONDAY AND INTO MONDAY NIGHT. INSTABILITY
CONTINUES TO LOOK WEAK...SO WILL KEEP JUST A SLIGHT CHANCE OF
THUNDER GOING. THE PROGRESSIVE NATURE OF THE COLD FRONT WILL KEEP
SHORT FUSE HYDRO PROBLEMS IN CHECK...BUT WILL LIKELY KEEP LARGER
CREEKS AND RIVERS UP. ONCE THE MAIN FRONT EXITS ON TUESDAY...A
SECONDARY SURGE OF MOISTURE AND FORCING WILL ARRIVE ON THE
EXISTING BAROCLINIC ZONE NEARBY OR JUST TO OUR SOUTHEAST. THE
ECMWF AND GFS DIFFER ON THE NORTHERN EXTENT OF THE FORCING AND
MOISTURE ON WEDNESDAY...BUT THE BLENDED POPS HAVE OVERALL BEEN
TRENDING HIGHER. HAVE FOLLOWED SUIT FOR NOW...BUT THERE IS LESS
CONFIDENCE IN THE QPF AMOUNTS AT THIS POINT. AS SUCH...WILL FOCUS
THE CONTINUATION OF THE ESF FOR EARLY NEXT WEEK...AND BECOME MORE
GENERALIZED WITH THE UNCERTAINTY FOR THE MIDDLE OF NEXT WEEK.
BY THURSDAY...THINGS LOOK TO FINALLY DRY OUT AS SURFACE RIDGING
NOSES IN FROM THE SOUTHWEST. MUCH COLDER AIR WILL ALSO BE MOVING
BACK IN BY THE END OF THE WORK WEEK AND INTO NEXT WEEKEND...BUT
NOT COUPLED WITH DEEPER MOISTURE...SO NO MORE MEASURABLE SNOW FOR
THE END OF THE YEAR CONTINUES TO LOOK VERY LIKELY. HIGHS WILL
DROP BACK INTO THE UPPER 30S AND LOWER 40S FOR MOST LOCATIONS BY
FRIDAY AND SATURDAY...WITH LOWS IN THE 20S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 150 PM EST SAT DEC 26 2015
A DEVELOPING WARM FRONT PUSHING INTO THE AREA IS LIFTING MOST OF
THE CONVECTION NORTH ALONG WITH IT. THIS IS BRUSHING THE LOZ AND
JKL TAF SITES AFTER DEPARTING SME. SYM WILL BE DEALING WITH THIS
AREA FOR THE LONGEST TIME INTO THE EARLY EVENING WHILE SJS MAY
MISS IT ALL TOGETHER AS THE MAIN PCPN STAYS TO THE WEST. WITH THIS
CONVECTION MVFR CIGS WILL BE POSSIBLE...ALONG WITH VIS AS LOW AS
IFR. HOWEVER...THIS ALL SHOULD LIFT FURTHER NORTH WITH TIME AND
SPARE THE AIRPORTS ACROSS EAST KENTUCKY MUCH IN THE WAY OF PCPN
THROUGH THE NIGHT AND INTO THE DAY SUNDAY. ACCORDINGLY...
CONDITIONS WILL BE MAINLY VFR THROUGH THE REST OF THE TAF
CYCLE...THOUGH SOME PATCHY FOG MAY BRING MVFR VIS TO THE SME AND
LOZ SITES IN THE EARLY MORNING HOURS. WINDS FOR THE AREA WILL BE
LIGHT AND VARIABLE THROUGH THE PERIOD...MAINLY FAVORING THE SOUTH
DIRECTION.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GREIF
LONG TERM...GEOGERIAN
AVIATION...GREIF
AREA FORECAST DISCUSSION
NWS JACKSON KY
300 PM EST SAT DEC 26 2015
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 300 PM EST SAT DEC 26 2015
19Z SFC ANALYSIS SHOWS DEEP LOW PRESSURE OFF TO THE SOUTHWEST OF
THE AREA WITH A WARM FRONT NOW LIFTING INTO AND THOUGH KENTUCKY.
SOME HEALTHY SHOWERS AND A FEW THUNDERSTORMS ARE BEING PUSHED
NORTH THROUGH THE AREA AHEAD OF THIS BOUNDARY. THE STRONGER
PORTIONS OF THIS CLUSTER IS FOUND JUST TO THE WEST OF THE JKL
CWA...BUT THE ENTIRE AREA IS PROGRESSIVE ENOUGH TO LIMIT ANY
RENEWED FLOODING CONCERNS FOR NORTHERN PARTS OF OUR AREA OF
RESPONSIBILITY. FOR THE SOUTHEAST PART OF EASTERN KENTUCKY THE
CLOUDS ARE SCATTERING OUT ALLOWING FOR MORE SUNSHINE WHILE THE
NORTHWEST REMAINS FAIRLY CLOUDY. THIS IS HAVING AN EFFECT ON
TEMPERATURES ACROSS WITH THE SOUTHEAST REACHING NEAR 70 DEGREES
WHILE THE NORTHWEST STILL HAS A FEW LOCATIONS IN THE UPPER 50S.
JKL HAS ALREADY SMASHED ITS RECORD HIGH FOR THE DAY...BUT LOZ MAY
NEED SOME GOOD CLOUD BREAKS TO EXCEED ITS RECORD. DEWPOINTS ALSO
VARY FROM SOUTHEAST TO NORTHWEST WITH LOWER 60S CLOSER TO
TENNESSEE AND VIRGINIA WHILE MID 50S ARE FOUND NORTH OF INTERSTATE
64. WINDS...MEANWHILE...ARE GENERALLY LIGHT FROM THE SOUTH TO
SOUTHEAST.
THE MODELS ARE IN GOOD AGREEMENT ALOFT THROUGH THE SHORT TERM.
THEY ALL DEPICT THE ANOMALOUSLY DEEP TROUGH CLOSING OFF ABOVE
NORTHERN MEXICO THIS EVENING HELPING TO PUMP THE SOUTHEAST RIDGE
DOWNSTREAM OVER KENTUCKY. ON SUNDAY...THE MODELS ROLL THIS UPPER
LOW INTO CENTRAL TEXAS WITH THE NAM SLIGHTLY STRONGER AND FURTHER
NORTH THAN THE GFS AND LATEST ECMWF. FOR KENTUCKY THIS YIELDS
HEIGHTS A SMIDGE HIGHER HEADING INTO SUNDAY NIGHT. THE GFS IS MORE
PROGRESSIVE WITH THE UPPER LOW INTO MONDAY MORNING WHILE THE ECMWF
AND NAM ARE IN BETTER AGREEMENT WITH A SLOWER MOVEMENT....REACHING
SOUTH CENTRAL OKLAHOMA BY 12Z VERSUS THE GFS POSITION OF THE LOW
CROSSING INTO ARKANSAS. HEIGHT DIFFERENCES REMAIN FOR EASTERN
KENTUCKY DOWNSTREAM WITH THE NAM/ECMWF ABOUT 30 DECAMETERS HIGHER
THAN THE GFS SOLUTION. THE BETTER AGREEMENT BETWEEN THE MORE
CONSISTENT ECMWF AND NAM LEND SUPPORT TO FAVORING THE NAM12 ON WX
DETAILS FOR THE SHORT TERM...IN CONJUNCTION WITH THE HRRR EARLY
ON.
SENSIBLE WEATHER WILL FEATURE THE MAJORITY OF ANY PCPN LIFTING
NORTH OF THE AREA BY EVENING WITH JUST A FEW STRAY SHOWERS
POSSIBLE INTO THE NIGHT...MAINLY CONFINED TO THE NORTHERN PARTS OF
THE AREA. GIVEN THE POSITION OF THE PCPN AND THICKER CLOUDS...
EXPECT A SMALL TO MODERATE RIDGE AND VALLEY SPLIT TO DEVELOP FOR
AT LEAST THE SOUTHERN 2/3RDS OF THE CWA. PATCHY VALLEY FOG WILL
ALSO BE POSSIBLE IN PLACES THAT HAVE THE THINNEST CLOUDS. FOR
SUNDAY...OUR WARMEST TEMPERATURES EVER RECORDED FOR DECEMBER
COULD BE THREATENED...DEPENDING ON THE QUALITY OF THE SUNSHINE
SEEN. HIGHS SHOULD EASILY BE IN THE MID 70S WITH UPPER 70S
POSSIBLE. DECEMBER/S RECORD HIGH FOR JKL IS 79 AND LOZ IS 78...
CERTAINLY WITHIN THE REALM OF POSSIBILITIES. ANY CONVECTION IN
THE WARM SECTOR SOUTH OF THE FRONT...LYING NORTH OF THE OHIO
RIVER...COULD END UP AS A THUNDERSTORM PARTICULARLY FOR LOCATIONS
NORTH OF THE MOUNTAIN PARKWAY. FOR SUNDAY AFTERNOON AND EVENING...
THE FRONT WILL START TO SHIFT SOUTH IN RESPONSE TO THE DEVELOPING
SFC LOW TO THE WEST. THIS WILL BRING A THREAT OF CONVECTION AND
HEAVY/TRAINING RAINS BACK INTO AT LEAST THE NORTHERN PARTS OF THE
AREA. THAT NIGHT THE CONVECTION WITH THE FRONT SHOULD WEAKEN AS
THE LOW APPROACHES WITH A STRIATION TO LOW TEMPERATURES DUE TO THE
WAGGLE OF THE BOUNDARY WITH SOME UPPER 40S POSSIBLE NORTH WHILE
THE SOUTH SETTLES INTO THE MID AND UPPER 50S.
FOR TEMPERATURES AND DEWPOINTS...AGAIN STARTED WITH THE SHORTBLEND
GUIDANCE THROUGH SUNDAY MORNING AND THEN THE SUPERBLEND INTO
MONDAY MORNING. MADE MORE SIGNIFICANT CHANGES TO THE LOWS TONIGHT
WITH A BETTER CHANCE FOR A RIDGE AND VALLEY DISTINCTION THROUGH
THE NIGHT FOR MUCH OF THE AREA. AS FOR POPS...ENDED UP CLOSER TO
THE WETTER MET NUMBERS FOR SUNDAY AND SUNDAY NIGHT.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 423 AM EST SAT DEC 26 2015
THE FEATURE OF CONCERN DURING THE EXTENDED PORTION OF THE FORECAST
WILL BE A STRONG WRAPPED UP UPPER LEVEL LOW...LOCATED OVER
NORTHERN MEXICO AND TX AS OF 18Z SUNDAY. WITH A HIGH PRESSURE
RIDGE OVER THE ATLANTIC JUST OFF THE SOUTHEAST CONUS...THIS WILL
ALLOW STRONG SW TO NE FLOW OF MOIST WARM AIR FROM THE GULF OF
MEXICO INTO THE OHIO RIVER VALLEY TO START OF THE
PERIOD...INCREASING AS THE LOW SLIDES EASTWARD TOWARD THE
SOUTHERN MISSISSIPPI RIVER VALLEY BY MONDAY MORNING. FROM
HERE...THE LOW IS EXPECTED TO INCREASE IN STRENGTH AS IT MAKES A
QUICK SHIFT NORTHEASTWARD UP THE MISSISSIPPI RIVER
VALLEY...REACHING FAR WESTERN KY BY 18Z MONDAY...AND THE UPPER
GREAT LAKES BY MONDAY NIGHT. FROM HERE IT WILL CONTINUE TRAVELING
NORTHEASTWARD WHILE LOSING CONSIDERABLE STRENGTH AND EVENTUALLY
FALLING APART. MEANWHILE...A NEW TROUGH WILL BEGIN DIGGING INTO
THE NORTHERN PLAINS TUESDAY NIGHT INTO WEDNESDAY...WITH DECREASING
HEIGHTS EXPECTED ACROSS THE OHIO RIVER VALLEY THROUGH THE REST OF
THE EXTENDED AS THE TROUGH SLOWLY SHIFTS EASTWARD WHILE BECOMING
SOMEWHAT DEAMPLIFIED.
AS FOR SENSIBLE WEATHER...A STRONG SURFACE LOW PRESSURE SYSTEM WILL
ACCOMPANY THE UPPER LEVEL LOW...CONTINUING THE PULL OF
WARM...MOIST...AND UNSTABLE AIR INTO THE OHIO RIVER VALLEY AT THE
SURFACE AS WELL...CORRELATING WELL WITH THE WARM FRONT WHICH WILL
EXTEND ACROSS MUCH OF KY SUNDAY NIGHT INTO MONDAY. THE ASSOCIATED
COLD FRONT WILL QUICKLY PASS THROUGH KENTUCKY AS THE SURFACE LOW AND
UPPER LEVEL LOW MAKE THE QUICK TRANSITION NORTH OF THE OHIO RIVER
VALLEY MONDAY INTO MONDAY NIGHT. THIS WILL CREATE A GOOD SCENARIO
FOR RAIN AND EVEN SOME THUNDER CHANCES MOVING INTO THE REGION LATE
SUNDAY NIGHT...MONDAY...AND INCREASING MONDAY AFTERNOON AND EVENING
ALONG AND JUST AHEAD OF THIS COLD FRONT. GIVEN THE STRENGTH AND
SPEED OF THIS SYSTEM...HIGH WIND GUSTS MAY BE OF A CONCERN AS THE
FRONT PASSES THROUGH. DRIER AIR WILL THEN FILTER IN BEHIND THE
FRONTAL PASSAGE MONDAY NIGHT INTO TUESDAY...WITH POPS SLOWLY
FALLING OFF THROUGH TUESDAY MORNING...AND TUESDAY AFTERNOON IN THE
HIGH TERRAIN.
SEVERAL SHORTWAVES ARE EXPECTED TO MOVE ACROSS THE EASTERN PORTION
OF THE CONUS AS GENERAL UPPER LEVEL TROUGHING TAKES HOLD ONCE MORE
FOR THE REST OF THE EXTENDED PERIOD. LONG RANGE MODELS ARE STILL
FAIRLY UN-AGREED UPON FOR WHEN AND TO WHAT EXTENT THESE SHORTWAVES
WILL AFFECT THE OHIO RIVER VALLEY AND EASTERN KY IN TERMS OF PRECIP.
AS SUCH...STUCK WITH THE MODEL BLEND AT THIS TIME...WHICH PULLS SOME
CHANCES OF RAIN BACK INTO THE REGION DURING THE DAY WEDNESDAY.
ANOTHER WEAKER SYSTEM MAY BRING SOME SLIGHT CHANCES BACK BY FRIDAY.
AS FOR TEMPERATURES...AFTER THE STRONG COLD FRONT MOVES THROUGH AT
THE BEGINNING OF THE PERIOD...AND WITH GENERAL TROUGHING TAKING HOLD
THEREAFTER...EXPECT A SLOW DECLINE IN TEMPERATURES THROUGHOUT THE
EXTENDED. THIS WILL BE AIDED BY GENERAL CLOUDINESS THROUGH A GOOD
PORTION OF THE FORECAST. WHILE SOME UPPER 60S ARE FORECAST ALONG THE
WARM FRONT DURING THE DAY MONDAY...BY THE WEEKEND...WE WILL LIKELY
DROP BELOW 40 DEGREES FOR HIGH TEMPERATURES. THIS WILL ALSO RESULT
IN OVERNIGHT BELOW FREEZING TEMPERATURES FOR THE NEW YEARS WEEKEND
AS WELL.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 150 PM EST SAT DEC 26 2015
A DEVELOPING WARM FRONT PUSHING INTO THE AREA IS LIFTING MOST OF
THE CONVECTION NORTH ALONG WITH IT. THIS IS BRUSHING THE LOZ AND
JKL TAF SITES AFTER DEPARTING SME. SYM WILL BE DEALING WITH THIS
AREA FOR THE LONGEST TIME INTO THE EARLY EVENING WHILE SJS MAY
MISS IT ALL TOGETHER AS THE MAIN PCPN STAYS TO THE WEST. WITH THIS
CONVECTION MVFR CIGS WILL BE POSSIBLE...ALONG WITH VIS AS LOW AS
IFR. HOWEVER...THIS ALL SHOULD LIFT FURTHER NORTH WITH TIME AND
SPARE THE AIRPORTS ACROSS EAST KENTUCKY MUCH IN THE WAY OF PCPN
THROUGH THE NIGHT AND INTO THE DAY SUNDAY. ACCORDINGLY...
CONDITIONS WILL BE MAINLY VFR THROUGH THE REST OF THE TAF
CYCLE...THOUGH SOME PATCHY FOG MAY BRING MVFR VIS TO THE SME AND
LOZ SITES IN THE EARLY MORNING HOURS. WINDS FOR THE AREA WILL BE
LIGHT AND VARIABLE THROUGH THE PERIOD...MAINLY FAVORING THE SOUTH
DIRECTION.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GREIF
LONG TERM...JMW
AVIATION...GREIF
AREA FORECAST DISCUSSION
NWS LAKE CHARLES LA
531 PM CST SUN DEC 27 2015
.DISCUSSION...
FOR THE 28/00Z TAF ISSUANCE.
&&
.AVIATION...
SURFACE LOW OVER NORTHEAST TEXAS WITH TRAILING COLD FRONT AROUND
THE HOUSTON AREA TO OFF INTO THE NORTHWEST GULF WILL CONTINUE TO
GRADUALLY LIFT OFF TO THE NORTHEAST DURING THE EVENING AND
OVERNIGHT. WITHIN A COUPLE OF HOURS OF TIMING...EXPECT THE COLD
FRONT AND ASSOCIATED SQUALL LINE TO MOVE NEAR KBPT BY
28/01Z...KLCH 28/02Z...KAEX 28/03Z AND KLFT/KARA 28/05Z. SHOWERS
AND STORMS ALONG SQUALL LINE WILL HAVE POTENTIAL WIND GUSTS OVER
40 KNOTS...HEAVY RAINFALL REDUCING VISIBILITIES TO IFR
LEVELS. MEANWHILE...SHOWERS AND STRONG SOUTH WINDS WITH MVFR
CEILINGS WILL PREVAIL AHEAD OF THIS FRONT.
BEHIND THE FRONT...WIND SHIFT TO A MORE WEST OR WEST-SOUTHWEST
DIRECTION IS EXPECTED. MVFR CEILINGS EXPECTED TO LINGER DURING THE
OVERNIGHT WITH VFR CONDITIONS GRADUALLY DEVELOPING ON MONDAY.
RUA
&&
.PREV DISCUSSION... /ISSUED 313 PM CST SUN DEC 27 2015/
DISCUSSION...
SHORT TERM...TONIGHT THROUGH MONDAY
THUNDERSTORMS ARE ORGANIZING ACROSS SE TEXAS LATE THIS AFTERNOON.
LATEST SHORT TERM GUIDANCE INCLUDING HRRR HAS CONVECTIVE LINE MOVING
THROUGH SW LOUISIANA THIS EVENING AND THROUGH ACADIANA AROUND
MIDNIGHT. WILL BE MONITORING FOR ROTATING DISCRETE CELLS AHEAD OF
LINE BUT BELIEVE MOST IMPACTS WILL BE FROM PASSING SQUALL LINE LATE
THIS AFTERNOON AND TONIGHT.
WILL EXTEND WIND ADVISORY UNTIL 12Z AS TIGHT GRADIENT IS
FORECASTED TO CONTINUE AS WINDS BECOME WNW.
THE PASSAGE OF THE LOW/FRONTAL BOUNDARY WILL FINALLY BRING AN END
TO THE UNSEASONABLY WARM LATE DECEMBER WEATHER. DRIER AND MUCH
COLDER CONDITIONS ARE EXPECTED BEGINNING MONDAY. MOST OF THE
FORECAST AREA IS EXPECTED TO REMAIN IN THE 50S FOR HIGHS. WITH A
COLDER AIR MASS IN PLACE AND HIGH PRESSURE OVER THE AREA TUESDAY
MORNING...WILL NEED THE MONITOR FOR THE POTENTIAL OF FREEZING
TEMPERATURES OVER THE TEXAS LAKES REGION AND CENTRAL LOUISIANA.
LONG TERM...TUESDAY THROUGH SUNDAY
MAIN FORECAST ISSUE IN THE LONG TERM WILL BE POPS.
MODELS INDICATE A SERIES OF PROGRESSIVE UPPER TROUGHS MOVING THROUGH
THE CENTRAL U.S. THROUGH THE WEEK. A STRONG SOUTHERN JET WILL BE
OVER THE SOUTHERN PLAINS AS WELL. WHILE PWATS ARE FORECASTED TO BE
BELOW AN INCH...THERE WILL BE A GOOD MOISTURE GRADIENT OVER THE
NORTHERN GULF. THIS COMBINED WITH SUFFICIENT PACIFIC MOISTURE WILL
BRING SCATTERED SHOWERS TUESDAY NIGHT AND WEDNESDAY. THE BEST CHANCE
FOR RAIN WILL BE OVER LOWER ACADIANA. WITH THE STRONG UPPER JET
OVER THE AREA LATE IN THE WEEK...WILL HAVE LOW POPS MAINLY OVER
COASTAL AREAS. TEMPERATURES THROUGH THE WEEK WILL TREND BELOW
NORMAL AS HIGH TEMPERATURES WILL BE MOSTLY IN THE 50S.
MARINE...ONLY CHANGES TO HAZARDS WILL BE TO EXTEND SCA FOR BAYS
UNTIL 12Z. SUSTAINED FORECAST WINDS WILL BE CLOSE ENOUGH FOR GALE
WARNING OFFSHORE BEGINNING AT 00Z.
STRONG ONSHORE FLOW WILL GRADUALLY SHIFT TO THE NW AS LOW PRESSURE
MOVES THROUGH THE AKLATX TONIGHT. HIGH PRESSURE WILL BUILD
BEGINNING MONDAY AFTERNOON ALLOWING FOR WINDS/WAVES TO DIMINISH.
STRONG OFFSHORE FLOW WILL EMERGE ON WEDNESDAY AS REINFORCING SURGE
OF COLD AIR MOVES OVER THE GULF. GRADIENT WILL LIKELY FURTHER
TIGHTEN AS A LOW PRESSURE SYSTEM TRIES TO ORGANIZE OVER THE BAY OF
CAMPECHE. WITH THE GOOD GRADIENT FORECASTED TO REMAIN OVER THE AREA
THROUGH THE WEEKEND...AN EXTENDED PERIOD OF SCA CONDITIONS APPEARS
LIKELY.
&&
.PRELIMINARY POINT TEMPS/POPS...
AEX 51 55 37 57 / 100 20 10 10
LCH 48 57 39 59 / 100 10 10 10
LFT 54 60 42 60 / 90 20 10 10
BPT 45 56 39 59 / 70 10 10 10
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...WIND ADVISORY UNTIL 6 AM CST MONDAY FOR LAZ027>033-041>045-
052>055-073-074.
COASTAL FLOOD ADVISORY UNTIL 6 AM CST MONDAY FOR LAZ041-052>054-
073-074.
TX...WIND ADVISORY UNTIL 6 AM CST MONDAY FOR TXZ180-201-215-216-
259>262.
COASTAL FLOOD ADVISORY UNTIL 6 AM CST MONDAY FOR TXZ215-216.
GM...SMALL CRAFT ADVISORY UNTIL 6 PM CST THIS EVENING FOR GMZ470-472-
475.
SMALL CRAFT ADVISORY FROM 6 AM TO NOON CST MONDAY FOR GMZ470-472-
475.
GALE WARNING UNTIL 6 AM CST MONDAY FOR GMZ470-472-475.
SMALL CRAFT ADVISORY UNTIL 6 AM CST MONDAY FOR GMZ430-432-435.
SMALL CRAFT ADVISORY UNTIL NOON CST MONDAY FOR GMZ450-452-455.
&&
$$
AVIATION...07
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
811 PM EST SUN DEC 27 2015
.SYNOPSIS...
A COLD FRONT DROPS THROUGH THE MID ATLANTIC TONIGHT INTO MONDAY
MORNING...BRINGING MUCH COOLER TEMPERATURES. THIS FRONT LIFTS BACK
NORTH AS A WARM FRONT MONDAY NIGHT INTO TUESDAY MORNING AS LOW
PRESSURE TRACKS INTO THE GREAT LAKES REGION. A WEAK COLD FRONT DROPS
INTO THE REGION TUESDAY NIGHT...WITH LOW PRESSURE TRACKING ALONG THE
BOUNDARY AND ACROSS THE AREA WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
THE CURRENT UPPER AIR ANALYSIS PER WV IMAGERY SHOWS A
POWERFUL LOW PRESSURE SYSTEM CENTERED OVER TX...WITH A STRONG
SUBTROPICAL RIDGE OVER THE WRN ATLANTIC. A MOIST FRONTAL BAND
EXTENDS NE FROM THE LOW THROUGH THE OHIO VALLEY AND INTO NEW
ENGLAND. AT THE SURFACE...A 1040MB HIGH IS CENTERED OVER THE NRN
PLAINS OF THE US AND SRN CANADA...AND IS BUILDING EWD ACROSS THE NRN
GREAT LAKES. THIS IS PUSHING A COLD FRONT SEWD WITH THE LEADING EDGE
REACHING THE OHIO VALLEY AND WRN SLOPES OF THE APPALACHIANS THIS
AFTERNOON.
THE MID-ATLANTIC REMAINS IN THE ANOMALOUSLY WARM AIRMASS THIS
AFTERNOON. TEMPERATURES AVERAGE IN THE LOW/MID 70S ALONG WITH A 10-
20 MPH SW WIND...WITH GUSTS TO 25 MPH. RECORD HIGHS HAVE ONCE AGAIN
BEEN BROKEN SEE THE CLIMO SECTION FOR MORE DETAILS. TEMPERATURES
REMAIN MILD THROUGH THE EVENING...THEN THE COLD FRONT WILL SWEEP
THROUGH THE REGION OVERNIGHT BRINGING A DRASTIC CHANGE IN
TEMPERATURE. READINGS FALL INTO THE MID 40S N BY EARLY MONDAY
MORNING...RANGING TO THE MID 50S S. THE 19Z/27 HRRR BRINGS THE COLD
FRONT INTO THE FAR NRN TIER OF THE AREA BY 03-04Z...A RIC-WAL LINE
BY 05-06Z...SRN VA/TIDEWATER BY 07-08Z...THEN ECG AREA BY 09-10Z.
THERE IS NOT MUCH FORCING FOR ASCENT WITH THE FRONT...SO POPS FOR
LIGHT RAIN ARE ONLY 20-30% LATER TONIGHT.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/...
HIGH PRESSURE BUILDS ACROSS NEW ENGLAND MONDAY. LOW-
LEVEL CAA (AOB 925MB) WILL CONTINUE THROUGH THE DAY WITH STEADY OR
SLOWLY FALLING TEMPERATURES. DAYTIME TEMPERATURES SHOULD BE IN THE
LOW/MID 40S N/NW AND LOW/MID 50S FAR SE...WHILE DAILY CLIMATE HIGHS
OCCUR SHORTLY AFTER MIDNIGHT TONIGHT. CLOUDY WITH A 20-25 MPH NE
WIND ALONG THE COAST (10-15 MPH INLAND)...AND A 20-30% CHC OF
OCCASIONAL LIGHT RAIN OVER THE PIEDMONT.
THE BOUNDARY THEN QUICKLY RETREATS N AS A WARM FRONT MONDAY NIGHT AS
THE AFOREMENTIONED STRONG LOW LIFTS THROUGH THE GREAT
LAKES...RESULTING IN RISING TEMPERATURES ALONG THE COAST OVERNIGHT
AND STEADY TEMPERATURES OVER THE PIEDMONT. CATEGORICAL POPS FOR RAIN
DEVELOP W-E ACROSS THE AREA MONDAY NIGHT...AND SHIFT TO THE COAST BY
TUESDAY MORNING AS THE WARM FRONT LIFTS THROUGH THE AREA. CURRENT
QPF AVERAGES ~0.50" N...TO ~0.25" S. THE STRONGER FORCING LIFTS WELL
NE OF THE AREA TUESDAY AFTERNOON...WITH RAIN TAPERING TO SHOWERS
ALONG THE COAST...AND PARTIAL CLEARING POSSIBLE W. HIGHS TUESDAY
WILL BE CHALLENGING OVER THE PIEDMONT...WHICH WILL LIKELY BE IN A
RESIDUAL WEDGE AIRMASS IN THE MORNING...BUT THEN COULD RISE SEVERAL
DEGREES BY AFTERNOON DEPENDING ON THE AMOUNT OF CLEARING. FARTHER E
WILL BE WITHIN THE WARM SECTOR WITH WELL ABOVE AVERAGE HIGHS ONCE
AGAIN RANGING FROM THE UPPER 60S TO MID 70S.
A WEAK COLD FRONT DROPS INTO THE AREA TUESDAY NIGHT. DRIER AIR
SHOULD BUILD IN FROM THE NW...BEFORE LIGHT ISENTROPIC LIFT DEVELOPS
LATE AS LOW PRESSURE APPROACHES FROM THE SW. POPS INCREASE TO 20-30%
LATE TUESDAY NIGHT...THEN INCREASE TO 50-60% WEDNESDAY AS THE LOW
TRACKS ACROSS THE AREA. THERE IS SOME MODEL DISAGREEMENT WITH THE
FRONTAL PLACEMENT AND TRACK OF THE LOW. LOWS MONDAY NIGHT RANGE
FROM AROUND 40 NW...TO THE MID 50S SE...FOLLOWED BY HIGHS
WEDNESDAY IN THE LOW 60S NW...TO NEAR 70 SE.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
LOW PRESSURE SLIDES EAST ACROSS FAR NRN NEW ENGLAND WED NIGHT...
PULLING A COLD FRONT THROUGH THE MID ATLANTIC REGION LATE WED
NIGHT INTO THU. WIDESPREAD RAINFALL WED NIGHT WILL GIVE WAY TO
DIMINISHING SHOWERS ON THU FROM NW TO SE AS THE DAY PROGRESSES.
THE COLD FRONT CLEARS THE COAST THU EVENING...ALLOWING A MUCH
COLDER CANADIAN AIRMASS TO USHER INTO THE AREA FRI THROUGH THE
REST OF THE UPCOMING WEEKEND. THIS AIRMASS WILL BE REINFORCED BY
A CLIPPER SYSTEM DIVING INTO THE GREAT LAKES/SRN ONTARIO LATE SAT
NIGHT/EARLY SUN...WHICH THEN PASSES ACROSS NEW ENGLAND THE REST
OF SUN.
TEMPERATURES CONTINUE TO RUN ABOVE SEASONAL NORMALS WED NIGHT/THU.
LOW TEMPERATURE DEPARTURES ARE AROUND +20 DEGREES WED NIGHT WITH
FORECAST LOWS IN THE 50S (UPPER 40S FAR NW COUNTIES). HIGH
TEMPERATURE DEPARTURES FOR THU ARE AROUND +10-15 DEGREES WITH
FORECAST HIGHS IN THE MID 50S NW TO MID 60S SE. TEMPS START TO
COOL OFF AS THE COOLER CANADIAN AIRMASS ARRIVES LATE THU NIGHT AND
CONTINUES TO SPILL INTO THE REGION THROUGH THE UPCOMING WEEKEND.
LOWS THU NIGHT IN THE 40S (MID-UPPER 30S POSSIBLE NW COUNTIES).
TEMPERATURES NEAR NORMAL FRI/FRI NIGHT WITH HIGHS IN THE
UPPER 40S NW TO MID 50S SE AND LOWS IN THE MID 20S TO LOWER 30S
INLAND (MID 30S IMMEDIATE COAST). TEMPS FINALLY DIP JUST BELOW
SEASONAL NORMALS SAT/SAT NIGHT. HIGHS IN THE MID-UPPER 40S
AREAWIDE. LOWS ONCE AGAIN IN THE MID 20S TO LOWER 30S INLAND (MID
30S IMMEDIATE COAST).
&&
.AVIATION /01Z MONDAY THROUGH FRIDAY/...
A COLD FRONT PASSES THROUGH THE AREA OVERNIGHT. THE FRONT RETURNS TO
THE N/NE MONDAY NIGHT. ANOTHER COLD FRONT AND ASSOCIATED LOW
PRESSURE SYSTEM AFFECTS THE REGION WEDNESDAY AND WEDNESDAY NIGHT.
AS OF 00Z...A MAINLY CLEAR SKY PREVAILED AT THE TAF SITES OTHER THAN
SOME HIGH CLOUDS. WINDS WERE FROM THE SW AT AROUND 10 KNOTS. A COLD
FRONT SITUATED ALONG THE MOUNTAINS TO OUR WEST WILL MOVE SOUTHEAST
AND THROUGH THE TAF SITES BETWEEN 05Z AND 10Z. WINDS SHIFT TO N/NE
BEHIND THE FRONT. MODELS ARE INDICATED A LOW STRATUS DECK FORMS
BEHIND THE FRONT AND WINDS GRADUALLY TO A MORE SOLID NE DIRECTION.
THIS STRATUS DECK SHOULD BE MVFR BUT MAY BE IFR FOR A FEW HOURS AT
ORF AND ECG.
OF MORE IMMEDIATE CONCERN IS THAT SOME MOS PRODUCTS HAVE LOW
CEILINGS AND EVEN FOG DEVELOP PRIOR TO THE FRONT. DISREGARDED THIS
FOR NOW EXCEPT AT ECG WHERE A BKN 15 HUNDRED DECK IS MENTIONED AT
07Z...THREE HOURS PRIOR TO FRONTAL PASSAGE. WILL NEED TO MONITOR FOR
THIS POSSIBILITY DURING THE COURSE OF THE EVENING AND EARLY MORNING.
RAIN DEVELOPS FROM THE WEST LATE IN THE DAY LATE MONDAY AFTERNOON
AND EVENING. HAVE CEILINGS LOWER TOWARD THE END OF THE TAF PERIOD
AND INCLUDED LIGHT RAIN AT RIC AFT 21Z.
OUTLOOK...RAIN BECOMES WIDESPREAD MONDAY NIGHT AND TAPERS OFF DURING
THE DAY TUESDAY. EXPECT IFR ACROSS THE AREA WITH THIS PCPN. VARIABLE
AVIATION CONDITIONS CAN BE EXPECTED FOLLOWING THIS RAIN. ANOTHER
WIDESPREAD RAIN EVENT IS FORECAST LATE WEDNESDAY INTO THURSDAY.
IMPROVING WEATHER IS EXPECTED BY FRIDAY AS A LARGE HIGH PRESSURE
BEGINS TO BUILD OVER THE MID ATLANTIC STATES.
&&
.MARINE...
A BRIEF SWLY SURGE THAT OCCURRED THIS AFTN IS SHOWING SIGNS OF
DIMINISHING AOB 15KT...THEREFORE SCA FLAGS WILL BE ALLOWED TO
EXPIRE AT 400 PM AS PLANNED.
MEANWHILE...AN APPROACHING COLD FRONT FROM THE NW IS SLOW TO MAKE
EWD PROGRESS...HOWEVER FLAT WLY FLOW ALOFT AND UPPER LEVEL
TROUGHING OVER ONTARIO/QUEBEC WILL BE ENOUGH TO PUSH THE FRONT
ACROSS THE WATERS FROM NORTH TO SOUTH AFTER MIDNIGHT TONIGHT INTO
MON MORNING. THE PRESSURE GRADIENT WILL QUICKLY TIGHTEN DUE TO
DECENT PRESSURE RISES BEHIND THE FRONT IN ADDITION TO A NICE SHOT
OF COLD AIR ADVECTION. WINDS WILL ALSO QUICKLY SHIFT FROM SW TO
N-NE AND INCREASE TO SOLID SCA SPEEDS OF 20-30KT AFTER MIDNIGHT
TONIGHT (AGAIN FROM NORTH TO SOUTH). NE-E WINDS WILL REMAIN STRONG
MON THROUGH EARLY TUE MORNING BEFORE DIMINISHING. LOW-END GALE
FORCE GUSTS COULD STILL BE POSSIBLE FOR NRN COASTAL WATERS BUT ARE
NOT EXPECTED TO POSSIBLY OCCUR UNTIL LATE MON AFTN/EVENING. 3-4FT
SEAS ARE EXPECTED TO QUICKLY BUILD TO 5FT IN NRN COASTAL WATERS
LATE TONIGHT...THEN BUILD TO 6-9FT ALL COASTAL WATERS BY MON AFTN
(EXCEPT SRN COASTAL WATERS THAT WILL BUILD TO 6-7FT FROM VA/NC
BORDER TO CURRITUCK LIGHT). SEAS THEN BUILD TO 8-10FT NRN COASTAL
WATERS LATE MON EVENING AND OVERNIGHT DUE TO A STRONG ONSHORE WIND
COMPONENT. HIGH SURF ADVISORIES MAY BE NEEDED ALONG THE ATLANTIC
SIDE OF THE MD/VA EASTERN SHORE DURING THIS TIMEFRAME. WAVES ON
CHES BAY WILL AVERAGE 1-3FT THIS EVENING THROUGH TONIGHT...THEN
BUILD TO 4-5FT EARLY MON MORNING AND PERSIST THROUGH MID-MORNING
TUE. THE MOUTH OF CHES BAY COULD SEE WAVES AS HIGH AS 6FT (MAYBE
EVEN 7FT) DUE TO NE-E WINDS PUSHING HIGHER SEAS INTO THE BAY.
PREVIOUSLY ISSUED SCA FLAGS HAVE BEEN EXTENDED THROUGH TUE MORNING
FOR CHES BAY...AND THROUGH TUE AFTN FOR THE SOUND AND ALL COASTAL
WATERS.
WEAK LOW PRESSURE LIFTS OVER THE WATERS TUE WITH WINDS BECOMING
MORE SLY AND DIMINISHING TO AOB 15KT DURING THE DAY...THEN
SHIFTING W-N LATE TUE NIGHT. SEAS AVERAGE 5-8FT ON EARLY TUE...
THEN SUBSIDE TO 3-5FT TUE NIGHT. WEAK LOW PRESSURE DEVELOPS ALONG
A STALLED FRONTAL BOUNDARY AND IS EXPECTED TO LIFT INTO THE REGION
FROM THE SW ON WED/WED NIGHT. A MUCH COLDER AIRMASS BEHIND THIS
SYSTEM WILL RESULT IN NLY WINDS THU THROUGH THE UPCOMING WEEKEND.
THE COLD AIR GETS REINFORCED DURING THIS TIME AND MAY RESULT IN
THE NEXT BEST CHANCE FOR SCA CONDITIONS ON SAT.
&&
.HYDROLOGY...
STONY CREEK HAS LEVELED OFF JUST UNDER MODERATE FLOODING. FLOOD
WARNINGS REMAIN IN EFFECT FOR MATTOAX...MATOACA...STONY CREEK AND
SEBRELL. MATTOAX HAS BEEN UPDATED TO TOUCH MODERATE FLOODING.
PLEASE SEE FLSAKQ FOR MORE INFO.
&&
.TIDES/COASTAL FLOODING...
INCREASING NE FLOW MON AND TUE WILL LEAD TO AN INCREASE IN TIDES
TO AROUND 1 FOOT ABV NORMAL MON NITE AND POSSIBLY UP TO 1.5 FT
ABOVE NORMAL TUE ACROSS NRN CSTL WTRS. THIS WILL LIKELY PUT SOME
STAGES WITHIN ONE HALF FOOT FROM MINOR FLOODING LEVELS AND
POSSIBLY LEAD TO COASTAL FLOOD STATEMENTS.
&&
.CLIMATE...
SEVERAL RECORDS SET OVER THE PAST 3 DAYS (SEE DATA BELOW). ADDITIONAL
RECORD TEMPERATURES WILL BE CHALLENGED TODAY.
*DENOTES NEW DAILY RECORD EITHER TIED OR BROKEN
**DENOTES NEW DEC RECORD EITHER TIED OR BROKEN FOR MONTH
RECORD HIGH TEMPS FOR DEC 24TH: RECORD HIGH MIN TEMPS FOR DEC 24TH:
RIC...71 IN 1988 (71*) RIC...49 IN 1979 (65**)
ORF...75 IN 1891 (82**) ORF...59 IN 1891 (68**)
SBY...70 IN 2014 (71*) SBY...50 IN 2014 (64**)
ECG...75 IN 1990 (77*) ECG...58 IN 1956 (67*)
RECORD HIGH TEMPS FOR DEC 25TH: RECORD HIGH MIN TEMPS FOR DEC 25TH:
RIC...74 IN 1955 (75*) RIC...58 IN 1964 (64*)
ORF...75 IN 1964 (79*) ORF...59 IN 1964 (66*)
SBY...73 IN 1932 (75*) SBY...60 IN 1964 (66**)
ECG...76 IN 1955 (78*) ECG...56 IN 1964 (68**)
RECORD HIGH TEMPS FOR DEC 26TH: RECORD HIGH MIN TEMPS FOR DEC 26TH:
RIC...74 IN 1982 RIC...58 IN 1964
ORF...75 IN 1891 ORF...64 IN 1964
SBY...70 IN 1964 SBY...60 IN 1964
ECG...74 IN 1982 (74*) ECG...64 IN 1964
RECORD HIGH TEMPS FOR DEC 27TH: RECORD HIGH MIN TEMPS FOR DEC 27TH:
RIC...73 IN 1971 (75*) RIC...60 IN 1949
ORF...72 IN 1971 (76*) ORF...61 IN 1949
SBY...68 IN 1971 (72*) SBY...60 IN 1949
ECG...71 IN 1971 (74*) ECG...60 IN 1949
ALL-TIME RECORD HIGH TEMPS FOR MONTH OF DEC:
RIC...81 IN 1998
ORF...81 IN 2013 (NEW RECORD ESTABLISHED DEC 24TH...82**)
SBY...77 IN 2013
ALL-TIME RECORD HIGH MIN TEMPS FOR MONTH OF DEC:
RIC...63 IN 1951 (NEW RECORD ESTABLISHED DEC 24TH...65**)
ORF...68 IN 2006 (RECORD TIED DEC 24TH...68**)
SBY...63 IN 2013 (NEW RECORD ESTABLISHED DEC 25TH...66**)
ECG...67 IN 1984 (NEW RECORD ESTABLISHED DEC 25TH...68**)
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 2 AM MONDAY TO 7 AM EST TUESDAY FOR
ANZ635>638.
SMALL CRAFT ADVISORY FROM 2 AM MONDAY TO 10 AM EST TUESDAY FOR
ANZ630>632-634.
SMALL CRAFT ADVISORY FROM 4 AM MONDAY TO 4 PM EST TUESDAY FOR
ANZ633.
SMALL CRAFT ADVISORY FROM 4 AM MONDAY TO 6 PM EST TUESDAY FOR
ANZ654-656-658.
SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO 6 PM EST TUESDAY
FOR ANZ650-652.
&&
$$
SYNOPSIS...AJZ/SAM
NEAR TERM...AJZ
SHORT TERM...AJZ/SAM
LONG TERM...BMD
AVIATION...LSA
MARINE...BMD/WRS
HYDROLOGY...
TIDES/COASTAL FLOODING...
CLIMATE...
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
804 PM EST SUN DEC 27 2015
.SYNOPSIS...
A COLD FRONT DROPS THROUGH THE MID ATLANTIC TONIGHT INTO MONDAY
MORNING...BRINGING MUCH COOLER TEMPERATURES. THIS FRONT LIFTS BACK
NORTH AS A WARM FRONT MONDAY NIGHT INTO TUESDAY MORNING AS LOW
PRESSURE TRACKS INTO THE GREAT LAKES REGION. A WEAK COLD FRONT DROPS
INTO THE REGION TUESDAY NIGHT...WITH LOW PRESSURE TRACKING ALONG THE
BOUNDARY AND ACROSS THE AREA WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
THE CURRENT UPPER AIR ANALYSIS PER WV IMAGERY SHOWS A
POWERFUL LOW PRESSURE SYSTEM CENTERED OVER TX...WITH A STRONG
SUBTROPICAL RIDGE OVER THE WRN ATLANTIC. A MOIST FRONTAL BAND
EXTENDS NE FROM THE LOW THROUGH THE OHIO VALLEY AND INTO NEW
ENGLAND. AT THE SURFACE...A 1040MB HIGH IS CENTERED OVER THE NRN
PLAINS OF THE US AND SRN CANADA...AND IS BUILDING EWD ACROSS THE NRN
GREAT LAKES. THIS IS PUSHING A COLD FRONT SEWD WITH THE LEADING EDGE
REACHING THE OHIO VALLEY AND WRN SLOPES OF THE APPALACHIANS THIS
AFTERNOON.
THE MID-ATLANTIC REMAINS IN THE ANOMALOUSLY WARM AIRMASS THIS
AFTERNOON. TEMPERATURES AVERAGE IN THE LOW/MID 70S ALONG WITH A 10-
20 MPH SW WIND...WITH GUSTS TO 25 MPH. RECORD HIGHS HAVE ONCE AGAIN
BEEN BROKEN SEE THE CLIMO SECTION FOR MORE DETAILS. TEMPERATURES
REMAIN MILD THROUGH THE EVENING...THEN THE COLD FRONT WILL SWEEP
THROUGH THE REGION OVERNIGHT BRINGING A DRASTIC CHANGE IN
TEMPERATURE. READINGS FALL INTO THE MID 40S N BY EARLY MONDAY
MORNING...RANGING TO THE MID 50S S. THE 19Z/27 HRRR BRINGS THE COLD
FRONT INTO THE FAR NRN TIER OF THE AREA BY 03-04Z...A RIC-WAL LINE
BY 05-06Z...SRN VA/TIDEWATER BY 07-08Z...THEN ECG AREA BY 09-10Z.
THERE IS NOT MUCH FORCING FOR ASCENT WITH THE FRONT...SO POPS FOR
LIGHT RAIN ARE ONLY 20-30% LATER TONIGHT.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/...
HIGH PRESSURE BUILDS ACROSS NEW ENGLAND MONDAY. LOW-
LEVEL CAA (AOB 925MB) WILL CONTINUE THROUGH THE DAY WITH STEADY OR
SLOWLY FALLING TEMPERATURES. DAYTIME TEMPERATURES SHOULD BE IN THE
LOW/MID 40S N/NW AND LOW/MID 50S FAR SE...WHILE DAILY CLIMATE HIGHS
OCCUR SHORTLY AFTER MIDNIGHT TONIGHT. CLOUDY WITH A 20-25 MPH NE
WIND ALONG THE COAST (10-15 MPH INLAND)...AND A 20-30% CHC OF
OCCASIONAL LIGHT RAIN OVER THE PIEDMONT.
THE BOUNDARY THEN QUICKLY RETREATS N AS A WARM FRONT MONDAY NIGHT AS
THE AFOREMENTIONED STRONG LOW LIFTS THROUGH THE GREAT
LAKES...RESULTING IN RISING TEMPERATURES ALONG THE COAST OVERNIGHT
AND STEADY TEMPERATURES OVER THE PIEDMONT. CATEGORICAL POPS FOR RAIN
DEVELOP W-E ACROSS THE AREA MONDAY NIGHT...AND SHIFT TO THE COAST BY
TUESDAY MORNING AS THE WARM FRONT LIFTS THROUGH THE AREA. CURRENT
QPF AVERAGES ~0.50" N...TO ~0.25" S. THE STRONGER FORCING LIFTS WELL
NE OF THE AREA TUESDAY AFTERNOON...WITH RAIN TAPERING TO SHOWERS
ALONG THE COAST...AND PARTIAL CLEARING POSSIBLE W. HIGHS TUESDAY
WILL BE CHALLENGING OVER THE PIEDMONT...WHICH WILL LIKELY BE IN A
RESIDUAL WEDGE AIRMASS IN THE MORNING...BUT THEN COULD RISE SEVERAL
DEGREES BY AFTERNOON DEPENDING ON THE AMOUNT OF CLEARING. FARTHER E
WILL BE WITHIN THE WARM SECTOR WITH WELL ABOVE AVERAGE HIGHS ONCE
AGAIN RANGING FROM THE UPPER 60S TO MID 70S.
A WEAK COLD FRONT DROPS INTO THE AREA TUESDAY NIGHT. DRIER AIR
SHOULD BUILD IN FROM THE NW...BEFORE LIGHT ISENTROPIC LIFT DEVELOPS
LATE AS LOW PRESSURE APPROACHES FROM THE SW. POPS INCREASE TO 20-30%
LATE TUESDAY NIGHT...THEN INCREASE TO 50-60% TUESDAY AS THE LOW
TRACKS ACROSS THE AREA. THERE IS SOME MODEL DISAGREEMENT WITH THE
FRONTAL PLACEMENT AND TRACK OF THE LOW. LOWS MONDAY NIGHT RANGE FROM
AROUND 40 NW...TO THE MID 50S SE...FOLLOWED BY HIGHS WEDNESDAY IN
THE LOW 60S NW...TO NEAR 70 SE.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
LOW PRESSURE SLIDES EAST ACROSS FAR NRN NEW ENGLAND WED NIGHT...
PULLING A COLD FRONT THROUGH THE MID ATLANTIC REGION LATE WED
NIGHT INTO THU. WIDESPREAD RAINFALL WED NIGHT WILL GIVE WAY TO
DIMINISHING SHOWERS ON THU FROM NW TO SE AS THE DAY PROGRESSES.
THE COLD FRONT CLEARS THE COAST THU EVENING...ALLOWING A MUCH
COLDER CANADIAN AIRMASS TO USHER INTO THE AREA FRI THROUGH THE
REST OF THE UPCOMING WEEKEND. THIS AIRMASS WILL BE REINFORCED BY
A CLIPPER SYSTEM DIVING INTO THE GREAT LAKES/SRN ONTARIO LATE SAT
NIGHT/EARLY SUN...WHICH THEN PASSES ACROSS NEW ENGLAND THE REST
OF SUN.
TEMPERATURES CONTINUE TO RUN ABOVE SEASONAL NORMALS WED NIGHT/THU.
LOW TEMPERATURE DEPARTURES ARE AROUND +20 DEGREES WED NIGHT WITH
FORECAST LOWS IN THE 50S (UPPER 40S FAR NW COUNTIES). HIGH
TEMPERATURE DEPARTURES FOR THU ARE AROUND +10-15 DEGREES WITH
FORECAST HIGHS IN THE MID 50S NW TO MID 60S SE. TEMPS START TO
COOL OFF AS THE COOLER CANADIAN AIRMASS ARRIVES LATE THU NIGHT AND
CONTINUES TO SPILL INTO THE REGION THROUGH THE UPCOMING WEEKEND.
LOWS THU NIGHT IN THE 40S (MID-UPPER 30S POSSIBLE NW COUNTIES).
TEMPERATURES NEAR NORMAL FRI/FRI NIGHT WITH HIGHS IN THE
UPPER 40S NW TO MID 50S SE AND LOWS IN THE MID 20S TO LOWER 30S
INLAND (MID 30S IMMEDIATE COAST). TEMPS FINALLY DIP JUST BELOW
SEASONAL NORMALS SAT/SAT NIGHT. HIGHS IN THE MID-UPPER 40S
AREAWIDE. LOWS ONCE AGAIN IN THE MID 20S TO LOWER 30S INLAND (MID
30S IMMEDIATE COAST).
&&
.AVIATION /01Z MONDAY THROUGH FRIDAY/...
A COLD FRONT PASSES THROUGH THE AREA OVERNIGHT. THE FRONT RETURNS TO
THE N/NE MONDAY NIGHT. ANOTHER COLD FRONT AND ASSOCIATED LOW
PRESSURE SYSTEM AFFECTS THE REGION WEDNESDAY AND WEDNESDAY NIGHT.
AS OF 00Z...A MAINLY CLEAR SKY PREVAILED AT THE TAF SITES OTHER THAN
SOME HIGH CLOUDS. WINDS WERE FROM THE SW AT AROUND 10 KNOTS. A COLD
FRONT SITUATED ALONG THE MOUNTAINS TO OUR WEST WILL MOVE SOUTHEAST
AND THROUGH THE TAF SITES BETWEEN 05Z AND 10Z. WINDS SHIFT TO N/NE
BEHIND THE FRONT. MODELS ARE INDICATED A LOW STRATUS DECK FORMS
BEHIND THE FRONT AND WINDS GRADUALLY TO A MORE SOLID NE DIRECTION.
THIS STRATUS DECK SHOULD BE MVFR BUT MAY BE IFR FOR A FEW HOURS AT
ORF AND ECG.
OF MORE IMMEDIATE CONCERN IS THAT SOME MOS PRODUCTS HAVE LOW
CEILINGS AND EVEN FOG DEVELOP PRIOR TO THE FRONT. DISREGARDED THIS
FOR NOW EXCEPT AT ECG WHERE A BKN 15 HUNDRED DECK IS MENTIONED AT
07Z...THREE HOURS PRIOR TO FRONTAL PASSAGE. WILL NEED TO MONITOR FOR
THIS POSSIBILITY DURING THE COURSE OF THE EVENING AND EARLY MORNING.
RAIN DEVELOPS FROM THE WEST LATE IN THE DAY LATE MONDAY AFTERNOON
AND EVENING. HAVE CEILINGS LOWER TOWARD THE END OF THE TAF PERIOD
AND INCLUDED LIGHT RAIN AT RIC AFT 21Z.
OUTLOOK...RAIN BECOMES WIDESPREAD MONDAY NIGHT AND TAPERS OFF DURING
THE DAY TUESDAY. EXPECT IFR ACROSS THE AREA WITH THIS PCPN. VARIABLE
AVIATION CONDITIONS CAN BE EXPECTED FOLLOWING THIS RAIN. ANOTHER
WIDESPREAD RAIN EVENT IS FORECAST LATE WEDNESDAY INTO THURSDAY.
IMPROVING WEATHER IS EXPECTED BY FRIDAY AS A LARGE HIGH PRESSURE
BEGINS TO BUILD OVER THE MID ATLANTIC STATES.
&&
.MARINE...
A BRIEF SWLY SURGE THAT OCCURRED THIS AFTN IS SHOWING SIGNS OF
DIMINISHING AOB 15KT...THEREFORE SCA FLAGS WILL BE ALLOWED TO
EXPIRE AT 400 PM AS PLANNED.
MEANWHILE...AN APPROACHING COLD FRONT FROM THE NW IS SLOW TO MAKE
EWD PROGRESS...HOWEVER FLAT WLY FLOW ALOFT AND UPPER LEVEL
TROUGHING OVER ONTARIO/QUEBEC WILL BE ENOUGH TO PUSH THE FRONT
ACROSS THE WATERS FROM NORTH TO SOUTH AFTER MIDNIGHT TONIGHT INTO
MON MORNING. THE PRESSURE GRADIENT WILL QUICKLY TIGHTEN DUE TO
DECENT PRESSURE RISES BEHIND THE FRONT IN ADDITION TO A NICE SHOT
OF COLD AIR ADVECTION. WINDS WILL ALSO QUICKLY SHIFT FROM SW TO
N-NE AND INCREASE TO SOLID SCA SPEEDS OF 20-30KT AFTER MIDNIGHT
TONIGHT (AGAIN FROM NORTH TO SOUTH). NE-E WINDS WILL REMAIN STRONG
MON THROUGH EARLY TUE MORNING BEFORE DIMINISHING. LOW-END GALE
FORCE GUSTS COULD STILL BE POSSIBLE FOR NRN COASTAL WATERS BUT ARE
NOT EXPECTED TO POSSIBLY OCCUR UNTIL LATE MON AFTN/EVENING. 3-4FT
SEAS ARE EXPECTED TO QUICKLY BUILD TO 5FT IN NRN COASTAL WATERS
LATE TONIGHT...THEN BUILD TO 6-9FT ALL COASTAL WATERS BY MON AFTN
(EXCEPT SRN COASTAL WATERS THAT WILL BUILD TO 6-7FT FROM VA/NC
BORDER TO CURRITUCK LIGHT). SEAS THEN BUILD TO 8-10FT NRN COASTAL
WATERS LATE MON EVENING AND OVERNIGHT DUE TO A STRONG ONSHORE WIND
COMPONENT. HIGH SURF ADVISORIES MAY BE NEEDED ALONG THE ATLANTIC
SIDE OF THE MD/VA EASTERN SHORE DURING THIS TIMEFRAME. WAVES ON
CHES BAY WILL AVERAGE 1-3FT THIS EVENING THROUGH TONIGHT...THEN
BUILD TO 4-5FT EARLY MON MORNING AND PERSIST THROUGH MID-MORNING
TUE. THE MOUTH OF CHES BAY COULD SEE WAVES AS HIGH AS 6FT (MAYBE
EVEN 7FT) DUE TO NE-E WINDS PUSHING HIGHER SEAS INTO THE BAY.
PREVIOUSLY ISSUED SCA FLAGS HAVE BEEN EXTENDED THROUGH TUE MORNING
FOR CHES BAY...AND THROUGH TUE AFTN FOR THE SOUND AND ALL COASTAL
WATERS.
WEAK LOW PRESSURE LIFTS OVER THE WATERS TUE WITH WINDS BECOMING
MORE SLY AND DIMINISHING TO AOB 15KT DURING THE DAY...THEN
SHIFTING W-N LATE TUE NIGHT. SEAS AVERAGE 5-8FT ON EARLY TUE...
THEN SUBSIDE TO 3-5FT TUE NIGHT. WEAK LOW PRESSURE DEVELOPS ALONG
A STALLED FRONTAL BOUNDARY AND IS EXPECTED TO LIFT INTO THE REGION
FROM THE SW ON WED/WED NIGHT. A MUCH COLDER AIRMASS BEHIND THIS
SYSTEM WILL RESULT IN NLY WINDS THU THROUGH THE UPCOMING WEEKEND.
THE COLD AIR GETS REINFORCED DURING THIS TIME AND MAY RESULT IN
THE NEXT BEST CHANCE FOR SCA CONDITIONS ON SAT.
&&
.HYDROLOGY...
STONY CREEK HAS LEVELED OFF JUST UNDER MODERATE FLOODING. FLOOD
WARNINGS REMAIN IN EFFECT FOR MATTOAX...MATOACA...STONY CREEK AND
SEBRELL. MATTOAX HAS BEEN UPDATED TO TOUCH MODERATE FLOODING.
PLEASE SEE FLSAKQ FOR MORE INFO.
&&
.TIDES/COASTAL FLOODING...
INCREASING NE FLOW MON AND TUE WILL LEAD TO AN INCREASE IN TIDES
TO AROUND 1 FOOT ABV NORMAL MON NITE AND POSSIBLY UP TO 1.5 FT
ABOVE NORMAL TUE ACROSS NRN CSTL WTRS. THIS WILL LIKELY PUT SOME
STAGES WITHIN ONE HALF FOOT FROM MINOR FLOODING LEVELS AND
POSSIBLY LEAD TO COASTAL FLOOD STATEMENTS.
&&
.CLIMATE...
SEVERAL RECORDS SET OVER THE PAST 3 DAYS (SEE DATA BELOW). ADDITIONAL
RECORD TEMPERATURES WILL BE CHALLENGED TODAY.
*DENOTES NEW DAILY RECORD EITHER TIED OR BROKEN
**DENOTES NEW DEC RECORD EITHER TIED OR BROKEN FOR MONTH
RECORD HIGH TEMPS FOR DEC 24TH: RECORD HIGH MIN TEMPS FOR DEC 24TH:
RIC...71 IN 1988 (71*) RIC...49 IN 1979 (65**)
ORF...75 IN 1891 (82**) ORF...59 IN 1891 (68**)
SBY...70 IN 2014 (71*) SBY...50 IN 2014 (64**)
ECG...75 IN 1990 (77*) ECG...58 IN 1956 (67*)
RECORD HIGH TEMPS FOR DEC 25TH: RECORD HIGH MIN TEMPS FOR DEC 25TH:
RIC...74 IN 1955 (75*) RIC...58 IN 1964 (64*)
ORF...75 IN 1964 (79*) ORF...59 IN 1964 (66*)
SBY...73 IN 1932 (75*) SBY...60 IN 1964 (66**)
ECG...76 IN 1955 (78*) ECG...56 IN 1964 (68**)
RECORD HIGH TEMPS FOR DEC 26TH: RECORD HIGH MIN TEMPS FOR DEC 26TH:
RIC...74 IN 1982 RIC...58 IN 1964
ORF...75 IN 1891 ORF...64 IN 1964
SBY...70 IN 1964 SBY...60 IN 1964
ECG...74 IN 1982 (74*) ECG...64 IN 1964
RECORD HIGH TEMPS FOR DEC 27TH: RECORD HIGH MIN TEMPS FOR DEC 27TH:
RIC...73 IN 1971 (75*) RIC...60 IN 1949
ORF...72 IN 1971 (76*) ORF...61 IN 1949
SBY...68 IN 1971 (72*) SBY...60 IN 1949
ECG...71 IN 1971 (74*) ECG...60 IN 1949
ALL-TIME RECORD HIGH TEMPS FOR MONTH OF DEC:
RIC...81 IN 1998
ORF...81 IN 2013 (NEW RECORD ESTABLISHED DEC 24TH...82**)
SBY...77 IN 2013
ALL-TIME RECORD HIGH MIN TEMPS FOR MONTH OF DEC:
RIC...63 IN 1951 (NEW RECORD ESTABLISHED DEC 24TH...65**)
ORF...68 IN 2006 (RECORD TIED DEC 24TH...68**)
SBY...63 IN 2013 (NEW RECORD ESTABLISHED DEC 25TH...66**)
ECG...67 IN 1984 (NEW RECORD ESTABLISHED DEC 25TH...68**)
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 2 AM MONDAY TO 7 AM EST TUESDAY FOR
ANZ635>638.
SMALL CRAFT ADVISORY FROM 2 AM MONDAY TO 10 AM EST TUESDAY FOR
ANZ630>632-634.
SMALL CRAFT ADVISORY FROM 4 AM MONDAY TO 4 PM EST TUESDAY FOR
ANZ633.
SMALL CRAFT ADVISORY FROM 4 AM MONDAY TO 6 PM EST TUESDAY FOR
ANZ654-656-658.
SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO 6 PM EST TUESDAY
FOR ANZ650-652.
&&
$$
SYNOPSIS...AJZ/SAM
NEAR TERM...AJZ
SHORT TERM...AJZ/SAM
LONG TERM...BMD
AVIATION...LSA
MARINE...BMD/WRS
HYDROLOGY...
TIDES/COASTAL FLOODING...
CLIMATE...
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
910 PM EST SUN DEC 27 2015
.UPDATE...
LATEST ITERATIONS OF THE RAP AND HRRR NOW REACHING INTO THE MONDAY
AFTERNOON PERIOD...AND IN CONJUCTION WITH RECENT OBSERVATIONS...
SIMPLY REINFORCE EARLIER EXPECTATIONS OF AN ONSET TIME FOR WINTRY
PRECIPITATION EXPANDING FROM SOUTH TO NORTH THROUGH THE AFTERNOON.
THIS TIMELINE DOES AFFORD A CLOSER LOOK AT THE ARRAY OF 00Z MODEL
GUIDANCE BEFORE MOVING FORWARD INTO THE WARNING/ADVISORY PHASE.
CURRENT HEADLINES PROPERLY DELINEATE CURRENT EXPECTATIONS AND THE
OVERALL MESSAGE...WHILE STILL CONVEYING SOME DEGREE OF UNCERTAINTY
/PARTICULARLY I-69 SOUTHWARD/ GIVEN THE OVERALL SENSITIVITY THIS
FORECAST CARRIES IN TERMS OF POSSIBLE MAGNITUDE AND DURATION OF
SLEET AND FREEZING RAIN BEFORE THE LOW LEVEL THERMAL PROFILE
ADVANCES ABOVE FREEZING. THEREFORE NO CHANGES ARE PLANNED TO CURRENT
HEADLINES THIS EVENING.
&&
.AVIATION...ISSUED 710 PM EST SUN DEC 27 2015
CONDITIONS TONIGHT AND MONDAY MORNING WILL BE DEFINED BY A DRIER
VEERING/NORTHEASTERLY FLOW...DOWNSTREAM OF AN ORGANIZING WINTER
STORM SYSTEM THAT WILL IMPACT THE REGION MONDAY AFTERNOON AND
EVENING. POCKETS OF PESKY MVFR STRATUS WILL REMAIN PROBLEMATIC
EARLY IN THE TAF PERIOD GIVEN THE FAVORABLE FLOW OFF LAKE HURON.
OTHERWISE ATTENTION IS ON THE WINTRY MIX EXPECTED TO EXPAND NORTH
ACROSS SE MICHIGAN FROM MID AFTERNOON INTO THE EVENING HOURS.
FAVORABLE ENVIRONMENT WILL EXIST TO SUPPORT PRIMARILY A
COMBINATION OF SLEET AND FREEZING RAIN DURING THE EARLY
STAGES...WITH AN ACCOMPANYING REDUCTION INTO MVFR/IFR DURING THIS
TIME. SOME UNCERTAINTY EXISTS IN BOTH THE DURATION AND END
TIME...BUT GENERALLY THE GREATEST WINDOW FOR THIS MIX OF
PRECIPITATION WILL FOCUS ACROSS THE NORTHERN TAF SITES /PTK TO
MBS/ WHERE A MORE SIGNIFICANT ACCUMULATION OF SLEET/ICE WILL BE
POSSIBLE. THIS MOISTURE WILL BE ACCOMPANIED BY A FIRM INCREASE IN
EASTERLY WIND. SUSTAINED WINDS IN EXCESS OF 15 KNOTS...WITH GUSTS
OF 25 TO 30 KNOTS.
AT DTW...NORTHEAST FLOW OFF LAKE HURON WILL SUPPORT THE MAINTENANCE
OF MVFR STRATUS THROUGH THE OVERNIGHT PERIOD. SOME REDUCTION IN
COVERAGE WILL BE PLAUSIBLE MONDAY MORNING IN ADVANCE OF DEEPER
MOISTURE ARRIVING FROM THE SOUTH. THIS MOISTURE WILL LEAD TO A
PERIOD OF FREEZING RAIN/SLEET LATE MONDAY...CENTERED 19Z-23Z. THERE
REMAINS SOME UNCERTAINTY AS TO THE OVERALL DURATION OF THIS WINTRY
MIX AND POTENTIAL FOR ICE ACCUMULATION...AS THIS MOISTURE WILL BE
ACCOMPANIED BY A SURGE OF WARMER AIR. STRENGTHENING EAST-NORTHEAST
FLOW /060-080/ AT THE SAME TIME...GUST POTENTIAL UP TO 30 KNOTS.
//DTW THRESHOLD PROBABILITIES...
* HIGH CONFIDENCE IN CEILING BELOW 5000 FT TONIGHT...MEDIUM MONDAY
MORNING.
* HIGH CONFIDENCE IN PRECIPITATION TYPE STARTING AS FZRA/IP AFTER
19Z MONDAY AFTERNOON...LOW IN TIMING TRANSITION TO RAIN.
* LOW CONFIDENCE IN REACHING CROSS WIND THRESHOLD FROM AN EASTERLY
WIND DIRECTION /070-080 DEG/ MONDAY AFTERNOON AND EVENING.
&&
.PREV DISCUSSION...ISSUED 403 PM EST SUN DEC 27 2015
DISCUSSION...
AS MORE 12/18Z GUIDANCE COMES IN...THINKING STILL ON TRACK FROM THE
EARLIER AFD UPDATE. THERE IS POTENTIAL FOR AROUND AN INCH OF SLEET
ACCUMULATION AND/OR 0.25 INCH OF FREEZING RAIN TO IMPACT SE MI
STARTING MONDAY AROUND 19Z...ENDING AROUND 06-09Z MONDAY NIGHT. THE
MAIN CHANGE WITH THIS FORECAST PACKAGE IS HIT HEAVIER ON SLEET
ACCUMULATION AND A LITTLE LESS ON FREEZING RAIN AS MODEL SOUNDINGS
CONTINUE TO TREND TOWARD A DEEPER COOLER BL. WINTER STORM WATCH
HEADLINES ARE OUT FOR COUNTIES NORTH OF I96. QUESTIONS REMAIN SOUTH
OF I96 AS TO WHETHER SFC TEMPS WILL STAY COLD LONG ENOUGH FOR ANY
SIGNIFICANT ACCUMULATIONS OF SLEET OR FREEZING RAIN SO WILL LEAVE
OUT OF THE WATCH AND CONTINUE TO MONITOR THERMAL TRENDS. REGARDLESS
OF WHETHER A HEADLINE IS OUT OR NOT...START TIME FOR PRECIP OVER THE
DETROIT METRO AREA LOOKS TO BE RIGHT AROUND THE EVENING COMMUTE.
BRIEF SYNOPSIS...DEEP UPPER LOW OVER TEXAS IN THE SOUTHERN STREAM OF
THE JET WILL RAPIDLY LIFT NORTHWARD ON MONDAY REACHING NORTHERN LAKE
MI BY TUESDAY MORNING. THE STRONG AND COMPACT 500MB VORT MAX WILL
LIFT NORTH THROUGH CHI BUT SEVERAL WAVES OF FORCING WILL TRACK ALONG
THE WARM FRONT UP THROUGH SOUTHERN MI LATE AFTERNOON AND EVENING
PRODUCING A MIX OF FROZEN PTYPES. A DIRECT FEED OF MOISTURE OFF THE
GOM WILL LEAD TO VERY MOIST MID LEVELS AS 850MB JET INCREASES TO
AROUND 70 KNOTS OVER THE OHIO VALLEY. THE DRY SLOT AND WARM AIR WILL
RAPIDLY LIFT NORTH OVERNIGHT WARMING THE BL RESULTING TO A
CHANGE OVER TO ALL RAIN.
PTYPE AND THERMAL PROFILES REMAIN A BIG FORECAST CHALLENGE WITH THIS
SYSTEM. FREEZING RAIN AND SLEET ARE VERY SENSITIVE TO THE THERMAL
PROFILE WITH EVEN A 1 DEGREE CHANGE AT THE SFC MAKING A LARGE
DIFFERENCE IN AMOUNT OF SLEET OR FZRA. DEWPOINTS IN THE UPPER 20S
WILL AIDE IN COOLER SFC TEMPS DURING THESE BANDS OF PRECIP AS WET
BULBING KNOCKS TEMPS BACK A COUPLE DEGREES LENDING SOME ADDITIONAL
SUPPORT TO THE FROZEN PTYPES. THE TIMING OF THE SFC FRONT AND WARM
AIR...SFC TEMPS >32F...WILL BE CRUCIAL FOR DETERMINING WHICH AREAS
GET HIT THE HARDEST. CURRENTLY IT LOOKS LIKE THE DETROIT METRO WILL
SEE A FEW HOURS OF FROZEN PTYPE BEFORE WARMER AIR LIFTS INTO THE
AREA...LIKELY BEGIN AROUND 19-21Z WHICH MAY AFFECT THE EVENING
COMMUTE SO AN ADVISORY MAY BE NEEDED FOR THOSE AREAS NOT COVERED BY
A WATCH CURRENTLY.
LASTLY...IN ADDITION TO THE PRECIP CONCERNS...EAST WINDS WILL BE
RATHER GUSTY IN THE LATE AFTERNOON/EARLY EVENING WITH GUSTS
EXCEEDING 30 MPH FOR A PERIOD. THE HIGHER WIND SPEEDS WILL POSE A
PROBLEM FOR THOSE AREAS SEEING FREEZING RAIN. ONCE THE WARM SECTOR
LIFTS INTO THE AREA AFTER MIDNIGHT...WINDS WILL RELAX THROUGH THE
REMAINDER OF THE OVERNIGHT.
THINGS QUIET DOWN A LITTLE INTO THE NEW YEAR. THE AREA WILL REMAIN
LOCKED IN A PERSISTENT LONGWAVE TROUGH DURING THIS TIME ALLOWING FOR
MULTIPLE SHORTWAVES TO RIDE THROUGH THE FLOW. THIS WILL BRING
SLIGHT CHANCES FOR SOME SNOW SHOWERS AND COOLER
WESTERLY/NORTHWESTERLY WINDS. WEDNESDAY TEMPS LOOKS TO BE THE
WARMEST THROUGH THE REMAINDER OF THE FORECAST PERIOD BEFORE TEMPS
SETTLE BACK DOWN TO AROUND NORMAL FOR THIS TIME OF YEAR.
MARINE...
FRESH NORTHERLY FLOW HAS BEEN IN PLACE TODAY OVER THE CENTRAL GREAT
LAKES AS ARCTIC HIGH PRESSURE BUILDS AGGRESSIVELY SOUTHWARD OUT OF
CANADA. SMALL CRAFT ADVISORIES REMAIN IN EFFECT FOR THE NEARSHORE
WATERS OF LAKE HURON. A STRONG WINTER STORM SYSTEM IS FORECASTED TO
LIFT NORTHWARD ALONG THE MISSISSIPPI RIVER VALLEY AND INTO THE
WESTERN GREAT LAKES MONDAY AND MONDAY NIGHT. WIDESPREAD EASTERLY
GALES REMAIN LIKELY OVER THE OPEN WATERS OF LAKE HURON AND THE
EXPOSED NEARSHORE ZONES. PEAK GUSTS OVER THE NORTHERN HALF OF LAKE
HURON ARE EXPECTED TO REACH 45 KNOT GALES MONDAY NIGHT. SIGNIFICANT
WAVE HEIGHTS WILL APPROACH 15 FEET IN THE REGION OF STRONGEST WINDS
WITH MAXIMUM WAVE HEIGHTS IN EXCESS OF 20 FEET.
HYDROLOGY...
A STRONG WINTER STORM SYSTEM WILL LIFT NORTHWARD THROUGH THE
MISSISSIPPI RIVER VALLEY AND WESTERN GREAT LAKES MONDAY AND MONDAY
NIGHT. THIS SYSTEM IS EXPECTED TO CARRY A HIGH AMOUNT OF GULF
MOISTURE WITH IT...BRINGING WIDESPREAD PRECIPITATION AMOUNTS OF .75
TO 1.0 INCH TO SOUTHEASTERN MICHIGAN. THERE REMAINS UNCERTAINTY TO
PRECIPIATION TYPE...BUT INDICATIONS ARE A SIGNIFICANT PORTION OF
PRECIPITATION MAY FALL IN THE FORM OF SLEET AND FREEZING RAIN.
ACCUMULATED ICE IS EXPECTED TO MELT QUICKLY WITH TEMPERATURES
EXPECTED TO RISE INTO THE UPPER 30S TO LOWER 40 BY TUESDAY MORNING.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...WINTER STORM WATCH FROM MONDAY AFTERNOON THROUGH LATE MONDAY NIGHT
FOR MIZ060>063-068>070.
WINTER STORM WATCH FROM MONDAY AFTERNOON THROUGH LATE MONDAY NIGHT
FOR MIZ047>049-053>055.
LAKE HURON...GALE WARNING FROM 7 AM MONDAY TO 10 AM EST TUESDAY FOR LHZ361>363-
421-441>443-462>464.
GALE WARNING FROM 10 AM MONDAY TO 4 AM EST TUESDAY FOR LHZ422.
SMALL CRAFT ADVISORY UNTIL 7 AM EST MONDAY FOR LHZ421-441>443.
LAKE ST CLAIR...GALE WARNING FROM 10 AM MONDAY TO 4 AM EST TUESDAY FOR LCZ460.
MICHIGAN WATERS OF LAKE ERIE...GALE WARNING FROM 10 AM MONDAY TO 4 AM EST TUESDAY FOR LEZ444.
&&
$$
UPDATE.......MR
AVIATION.....MR
DISCUSSION...DRK/SS
MARINE.......CB
HYDROLOGY....CB
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
339 PM EST SAT DEC 26 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 552 AM EST SAT DEC 26 2015
WATER VAPOR IMAGERY AND RAP ANALYSIS SHOW A SRN STREAM TROF OVER THE
ROCKIES WITH SW FLOW DOWNSTREAM INTO THE UPPER GREAT LAKES. TO THE N
IN THE NRN STREAM...A BROADER TROF COVERS MUCH OF CANADA. TIGHTENING
CONFLUENT FLOW BTWN THE 2 BRANCHES IS SETTING UP A STRENGTHENING
UPPER JET IN THE VCNTY OF THE UPPER GREAT LAKES INTO SE CANADA.
MEANWHILE...SHORTWAVE FROM THE SRN STREAM TROF IS EJECTING NE ACROSS
THE WRN PLAINS. COMBINATION OF STRENGTHENING RIGHT ENTRANCE UPPER
JET FORCING AND EJECTING ENERGY HAS LED TO PCPN DEVELOPMENT FROM
NEBRASKA NE INTO ECNTRL MN.
INHERITED FCST IS GENERALLY ON TRACK...BUT SOME REFINEMENTS HAVE
BEEN NEEDED. STRENGTHENING FGEN IN RESPONSE TO STRENGTHENING UPPER
JET AND SHARPENING ISOTACH GRADIENT WILL SUPPORT CONTINUED SPREAD OF
PCPN NE INTO THE UPPER GREAT LAKES TODAY. THE MOST ACTIVE FGEN
RESPONSE/STRENGTHENING IS A BIT HIGHER INTO THE MID LEVELS THAN
TYPICALLY SEEN SO THE HEAVIER BAND OF SNOW WILL BE DISPLACED QUITE A
BIT FARTHER N OF THE SFC/850MB FRONT THAN ONE WOULD NORMALLY SEE.
BIGGEST CONCERN THIS MORNING IS LOW-LEVEL EASTERLY FLOW HOLDING IN
DRIER AIR AT THE LOW LEVELS ACROSS CNTRL AND ERN UPPER MI. MOST OF
THE 00Z HIGH RES MODEL GUIDANCE HAS MAINTAINED ENOUGH DRY AIR TO
SHIFT MAIN AREA OF SNOW A BIT W AND N OF WHAT WAS PREVIOUSLY
EXPECTED. HOURLY RAP/HRRR MODEL RUNS THRU THE NIGHT HAVE CONTINUED
TO MAINTAIN OR EVEN STRENGTHEN THE LOW LEVEL DRY AIR AS HAS THE 06Z
NAM. AS A RESULT...THIS MORNINGS FCST HAS TRENDED POPS/HEAVIEST SNOW
A BIT W AND N...RESULTING IN IRON COUNTY WINTER WX ADVY BEING
DROPPED. MARQUETTE COUNTY COULD SEE QUITE A GRADIENT FROM SE TO NW
TODAY...WITH POTENTIAL FOR AREAS S AND E OF MARQUETTE TO SEE LITTLE
OR NOTHING WHILE SEVERAL INCHES OF SNOW FALL N AND W OF NEGAUNEE.
FARTHER W AND NW...LOOKS LIKE A SOLID ADVY SNOWFALL TODAY OF 3-6
INCHES. BIGGEST CONCERN IS THE KEWEENAW WHERE SOME LAKE ENHANCEMENT
COULD OCCUR UNDER ENE LOW-LEVEL WINDS...POTENTIALLY REQUIRING
UPGRADING OF HEADLINE. WILL NEED TO MONITOR SNOW TRENDS AFTER
SYNOPTIC SNOW ARRIVES TO SEE WHERE OR IF ENHANCEMENT TAKES SHAPE.
LATE THIS AFTN/EVENING...PCPN SHOULD EXPAND ACROSS THE CNTRL AND ERN
FCST AREA AS A PUSH OF STRONGER ISENTROPIC ASCENT/MOISTURE ADVECTION
SHIFTS ACROSS THE AREA. PCPN DURATION SHOULD BE BRIEF ENOUGH TO
PRECLUDE ANY NEED FOR HEADLINES ACROSS THE SCNTRL/E WITH ONLY 1-2
INCHES OF SNOW. CLOSE TO LAKE MI IN MENOMINEE COUNTY...PCPN MAY MIX
WITH RAIN FOR A TIME. BACK TO WRN AND NCNTRL UPPER MI...SYNOPTIC
SNOW WILL WIND DOWN...BUT LAKE/UPSLOPE ENHANCEMENT SHOULD SUPPORT AS
MUCH AS 3-4 INCHES OF ADDITIONAL SNOW IN THE FAVORED HIGH TERRAIN
AREAS AS WINDS BACK FROM NE TO N.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 339 PM EST SAT DEC 26 2015
NAM SHOWS A CLOSED 500 MB LOW OVER CENTRAL TX 00Z MON THAT HEADS
NORTHEAST TO CENTRAL MISSOURI BY 00Z TUE. THIS CLOSED LOW HEADS DUE
NORTH INTO NE WI 12Z TUE AND TO ERN ONTARIO BY 00Z WED. NAM BRINGS
IN SOME 850-500 MB Q-VECTOR CONVERGENCE AND DEEPER MOISTURE INTO THE
AREA MON NIGHT INTO TUE MORNING.
THIS STORM LOOKS TO BE SIGNIFICANT WITH HEAVY SNOW AND THIS WOULD BE
A 5TH PERIOD WATCH IF ONE WAS ISSUED. WILL HOLD OFF FOR NOW AS
TIMING COULD BE A BIT OF AN ISSUE COMING UP FROM THE SOUTHWEST...BUT
QPF WOULD BE 0.50-0.90 INCH WHICH WOULD TRANSLATE TO ABOUT 4.5 TO 9
INCHES OF SNOW FOR THE AREA. WINDS WILL BE FROM THE NORTH NORTHEAST
AND IS COLD ENOUGH FOR SOME LAKE ENHANCEMENT AS WELL. WILL MENTION
THIS IN THE HWO. OTHERWISE...LAKE EFFECT SNOW SHOWERS WILL CONTINUE
THIS PERIOD WITH A DIMINISHING TREND. DID NOT MAKE TOO MANY CHANGES
TO THE GOING TEMPERATURES.
IN THE EXTENDED...GFS AND ECMWF SHOW A 500 MB TROUGH OVER THE PLAINS
12Z WED WHICH MOVES INTO THE UPPER GREAT LAKES 12Z THU WITH
TROUGHING REMAINING INTO 12Z SAT WITH COLDER AIR AT 850 MB FLOWING
ACROSS LAKE SUPERIOR. WATER TEMPERATURES ARE AROUND 4C AND 850 MB
TEMPERATURES DROP TO -12C WHICH IS ENOUGH FOR LAKE EFFECT SNOW FOR
00Z FRI. TEMPERATURES LOOK TO BE NEAR NORMAL FOR THIS FORECAST
PERIOD WITH LAKE EFFECT SNOW SHOWERS THE GENERAL RULE NEAR LAKE
SUPERIOR.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1244 PM EST SAT DEC 26 2015
KIWD...BEST SYSTEM SNOW HAS PASSED...BUT WILL SEE WORSENING
CONDITIONS AS LAKE EFFECT PICKS UP TONIGHT INTO SUNDAY.
KCMX...SHOULD SEE CONTINUED LIGHT TO POSSIBLY MODERATE SNOW AS
SYSTEM SNOW IS ENHANCED BY UPSLOPE/LAKE ENHANCEMENT. SOME MODELS
HINTED AT LOWER VIS TO AROUND A HALF MILE...BUT THINK THAT WILL NOT
BE COMMON ENOUGH TO INCLUDE IN THE TAF. WILL SEE SOME IMPROVEMENT AS
SYSTEM SNOW MOVES OUT AND LAKE EFFECT INCREASES TONIGHT INTO SUNDAY.
KSAW...DRY AIR CONTINUES TO WIND OUT SOUTH OF A STRONG SNOW BAND.
EXPECT MOISTURE TO MOVE IN AND ALLOW SNOW AND REDUCED CIG/VIS LATE
THIS AFTERNOON AND EVENING. CONDITIONS WILL STAY POOR INTO SUNDAY AS
LAKE EFFECT STARTS UP.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 552 AM EST SAT DEC 26 2015
E TO NE WINDS WILL INCREASE TODAY UNDER TIGHTENING PRES GRADIENT
BTWN HIGH PRES RIDGE LIFTING N INTO NRN ONTARIO AND LOW PRES TROF
ORGANIZING FROM THE SRN PLAINS TO THE LOWER LAKES. EXPECT WINDS OF
20-30KT OVER WRN LAKE SUPERIOR AND 15-25KT ACROSS THE E. WINDS WILL
DIMINISH A LITTLE TONIGHT BEFORE INCREASING AGAIN ON SUN...THIS TIME
OVER ERN LAKE SUPERIOR WHERE WINDS WILL REACH 20-30KT. HEADING INTO
MON/MON NIGHT...LATEST INDICATIONS ARE FOR A WEAKENING LOW PRES
SYSTEM TO LIFT INTO THE GREAT LAKES WHILE STRONG HIGH PRES RESIDES N
AND NE OF LAKE SUPERIOR. THIS SHOULD RESULT IN A PERIOD OF EASTERLY
GALES DEVELOPING MON/MON EVENING. WINDS WILL THEN DIMINISH TUE AND
BECOME LIGHT...MAINLY UNDER 15KT ON WED.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 10 AM EST /9 AM CST/ SUNDAY FOR
MIZ001>005-009-084.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...07
AVIATION...TITUS
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1246 PM EST SAT DEC 26 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 552 AM EST SAT DEC 26 2015
WATER VAPOR IMAGERY AND RAP ANALYSIS SHOW A SRN STREAM TROF OVER THE
ROCKIES WITH SW FLOW DOWNSTREAM INTO THE UPPER GREAT LAKES. TO THE N
IN THE NRN STREAM...A BROADER TROF COVERS MUCH OF CANADA. TIGHTENING
CONFLUENT FLOW BTWN THE 2 BRANCHES IS SETTING UP A STRENGTHENING
UPPER JET IN THE VCNTY OF THE UPPER GREAT LAKES INTO SE CANADA.
MEANWHILE...SHORTWAVE FROM THE SRN STREAM TROF IS EJECTING NE ACROSS
THE WRN PLAINS. COMBINATION OF STRENGTHENING RIGHT ENTRANCE UPPER
JET FORCING AND EJECTING ENERGY HAS LED TO PCPN DEVELOPMENT FROM
NEBRASKA NE INTO ECNTRL MN.
INHERITED FCST IS GENERALLY ON TRACK...BUT SOME REFINEMENTS HAVE
BEEN NEEDED. STRENGTHENING FGEN IN RESPONSE TO STRENGTHENING UPPER
JET AND SHARPENING ISOTACH GRADIENT WILL SUPPORT CONTINUED SPREAD OF
PCPN NE INTO THE UPPER GREAT LAKES TODAY. THE MOST ACTIVE FGEN
RESPONSE/STRENGTHENING IS A BIT HIGHER INTO THE MID LEVELS THAN
TYPICALLY SEEN SO THE HEAVIER BAND OF SNOW WILL BE DISPLACED QUITE A
BIT FARTHER N OF THE SFC/850MB FRONT THAN ONE WOULD NORMALLY SEE.
BIGGEST CONCERN THIS MORNING IS LOW-LEVEL EASTERLY FLOW HOLDING IN
DRIER AIR AT THE LOW LEVELS ACROSS CNTRL AND ERN UPPER MI. MOST OF
THE 00Z HIGH RES MODEL GUIDANCE HAS MAINTAINED ENOUGH DRY AIR TO
SHIFT MAIN AREA OF SNOW A BIT W AND N OF WHAT WAS PREVIOUSLY
EXPECTED. HOURLY RAP/HRRR MODEL RUNS THRU THE NIGHT HAVE CONTINUED
TO MAINTAIN OR EVEN STRENGTHEN THE LOW LEVEL DRY AIR AS HAS THE 06Z
NAM. AS A RESULT...THIS MORNINGS FCST HAS TRENDED POPS/HEAVIEST SNOW
A BIT W AND N...RESULTING IN IRON COUNTY WINTER WX ADVY BEING
DROPPED. MARQUETTE COUNTY COULD SEE QUITE A GRADIENT FROM SE TO NW
TODAY...WITH POTENTIAL FOR AREAS S AND E OF MARQUETTE TO SEE LITTLE
OR NOTHING WHILE SEVERAL INCHES OF SNOW FALL N AND W OF NEGAUNEE.
FARTHER W AND NW...LOOKS LIKE A SOLID ADVY SNOWFALL TODAY OF 3-6
INCHES. BIGGEST CONCERN IS THE KEWEENAW WHERE SOME LAKE ENHANCEMENT
COULD OCCUR UNDER ENE LOW-LEVEL WINDS...POTENTIALLY REQUIRING
UPGRADING OF HEADLINE. WILL NEED TO MONITOR SNOW TRENDS AFTER
SYNOPTIC SNOW ARRIVES TO SEE WHERE OR IF ENHANCEMENT TAKES SHAPE.
LATE THIS AFTN/EVENING...PCPN SHOULD EXPAND ACROSS THE CNTRL AND ERN
FCST AREA AS A PUSH OF STRONGER ISENTROPIC ASCENT/MOISTURE ADVECTION
SHIFTS ACROSS THE AREA. PCPN DURATION SHOULD BE BRIEF ENOUGH TO
PRECLUDE ANY NEED FOR HEADLINES ACROSS THE SCNTRL/E WITH ONLY 1-2
INCHES OF SNOW. CLOSE TO LAKE MI IN MENOMINEE COUNTY...PCPN MAY MIX
WITH RAIN FOR A TIME. BACK TO WRN AND NCNTRL UPPER MI...SYNOPTIC
SNOW WILL WIND DOWN...BUT LAKE/UPSLOPE ENHANCEMENT SHOULD SUPPORT AS
MUCH AS 3-4 INCHES OF ADDITIONAL SNOW IN THE FAVORED HIGH TERRAIN
AREAS AS WINDS BACK FROM NE TO N.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 459 AM EST SAT DEC 26 2015
A SIGNIFICANT LARGE-SCALE PATTERN CHANGE WILL BE UNDERWAY AT THE
START OF THE FORECAST PERIOD AS DEEP TROUGHING DEVELOPS ACROSS THE
CENTRAL CONUS FOR THE UPCOMING WEEK.
SUNDAY...SHORTWAVE TROUGHING OVER THE UPPER MS VALLEY WILL BE
SHIFTING EASTWARD WHILE PHASING WITH A PIECE OF ENEGERY THAT EJECTED
FROM A CLOSED LOW OVER THE SW STATES. WITH SYNOPTIC MOISTURE FROM
TODAYS SYSTEM HAVING ALREADY DEPARTED...PRECIP WILL BE CONFINED TO
LES ALONG LAKE SUPERIOR. WITH INVERSIONS LOWERING TO UNDER 4KFT AND
DEEP DRY AIR ADVECTING ACROSS THE UPPER GREAT LAKES...DO NOT EXPECT
ANY INTENSE LES. RATHER...THE SHALLOW CLOUD MOSTLY LOCATED WITHIN
THE DGZ SUPPORTS PERIODS OF LIGHT TO INFREQUENTLY MODERATE FLUFFY
LES FOR MAINLY THE NW-WIND SNOW BELTS...ESPECIALLY EAST WHERE LOW-
LEVEL CONV IS ENHANCED BY A LINGERING LOW-LEVEL THERMALLY INDUCED
TROUGH OVER LAKE SUPERIOR.
SUNDAY NIGHT THROUGH TUESDAY...MODEL GUIDANCE HAS HAD SOME SERIOUS
STRUGGLES WITH HOW TO HANDLE THE CUTOFF LOW OVER THE SW STATES. 24
HOURS AGO...GUIDANCE WAS TRENDING TOWARD SENDING THE LOW WELL TO THE
SE. NOW...NEARLY THE WHOLE MODEL SUITE HAS SHIFTED WELL TO THE NW.
THE SFC LOW IS NOW PROGGED TO TRACK ACROSS THE UPPER GREAT LAKES
MONDAY NIGHT INTO TUESDAY MORNING.
AS THE SFC LOW APPROACHES...LES ALONG LAKE SUPERIOR WILL SHIFT TO
THE NE WIND BELTS BY DAYBREAK MONDAY...AND THE EAST WIND BELTS BY
MONDAY AFTERNOON. SIGNIFICANT LOW LEVEL DRYING ASSOCIATED WITH A
STRONG 1040 MB HIGH OVER ONTARIO WILL LIKELY LIMIT LES ACTIVITY TO
JUST SOME ISOLATED TO SCATTERED LIGHT SHOWERS.
THE BEST FORCING FROM COUPLED UPPER JET STREAKS AND MID-LEVEL Q-
VECTOR CONV ARE STILL FORECAST TO REMAIN SOUTHEAST OF THE CWA...BUT
A MODEST DEFORMATION BAND ON THE NW SIDE OF THE WILL HAVE THE
POTNETIAL TO BRING SEVERAL INCHES OF ACCUMULATING SNOW ACROSS THE
CWA MONDAY NIGHT INTO EARLY TUESDAY MORNING. THE AFFORMENTED DRY NE
FLOW OFF ONTARIO WILL LIKELY LIMIT SNOWFALL TOTALS...SO DO NOT SEE
ANYTHING MORE THAN AN ADVISORY-LEVEL SNOW AT THIS TIME.
EAST WINDS WILL QUICKLY INCREASE ON MONDAY WITH THE TIGHTENING
PRESSURE GRADIENT BETWEEN THE APPROACHING LOW AND ONTARIO HIGH.
EXPOSED LOCATIONS TO EAST WINDS ALONG THE GREAT LAKES AND HIGH
TERRAIN SHOULD EXPERIENCE FREQUENT GUSTS TO 35 MPH LATE IN THE
AFTERNOON AND WELL INTO MONDAY NIGHT.
WEDNESDAY THROUGH FRIDAY...A PAIR OF MID-LEVEL TROUGHS ARE SET TO
CROSS THE UPPER GREAT LAKES ON WEDNESDAY AND THURSDAY. WITH RATHER
BROAD FORCING AND LIMITED MOISTURE...NEITHER LOOK TO BRING MORE THAN
A COUPLE INCHES OF SNOW. LES FOR THE NW WIND SNOW BELTS THEN
DEVELOPS BEHIND THESE TROUGHS ON FRIDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1244 PM EST SAT DEC 26 2015
KIWD...BEST SYSTEM SNOW HAS PASSED...BUT WILL SEE WORSENING
CONDITIONS AS LAKE EFFECT PICKS UP TONIGHT INTO SUNDAY.
KCMX...SHOULD SEE CONTINUED LIGHT TO POSSIBLY MODERATE SNOW AS
SYSTEM SNOW IS ENHANCED BY UPSLOPE/LAKE ENHANCEMENT. SOME MODELS
HINTED AT LOWER VIS TO AROUND A HALF MILE...BUT THINK THAT WILL NOT
BE COMMON ENOUGH TO INCLUDE IN THE TAF. WILL SEE SOME IMPROVEMENT AS
SYSTEM SNOW MOVES OUT AND LAKE EFFECT INCREASES TONIGHT INTO SUNDAY.
KSAW...DRY AIR CONTINUES TO WIND OUT SOUTH OF A STRONG SNOW BAND.
EXPECT MOISTURE TO MOVE IN AND ALLOW SNOW AND REDUCED CIG/VIS LATE
THIS AFTERNOON AND EVENING. CONDITIONS WILL STAY POOR INTO SUNDAY AS
LAKE EFFECT STARTS UP.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 552 AM EST SAT DEC 26 2015
E TO NE WINDS WILL INCREASE TODAY UNDER TIGHTENING PRES GRADIENT
BTWN HIGH PRES RIDGE LIFTING N INTO NRN ONTARIO AND LOW PRES TROF
ORGANIZING FROM THE SRN PLAINS TO THE LOWER LAKES. EXPECT WINDS OF
20-30KT OVER WRN LAKE SUPERIOR AND 15-25KT ACROSS THE E. WINDS WILL
DIMINISH A LITTLE TONIGHT BEFORE INCREASING AGAIN ON SUN...THIS TIME
OVER ERN LAKE SUPERIOR WHERE WINDS WILL REACH 20-30KT. HEADING INTO
MON/MON NIGHT...LATEST INDICATIONS ARE FOR A WEAKENING LOW PRES
SYSTEM TO LIFT INTO THE GREAT LAKES WHILE STRONG HIGH PRES RESIDES N
AND NE OF LAKE SUPERIOR. THIS SHOULD RESULT IN A PERIOD OF EASTERLY
GALES DEVELOPING MON/MON EVENING. WINDS WILL THEN DIMINISH TUE AND
BECOME LIGHT...MAINLY UNDER 15KT ON WED.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 10 AM EST /9 AM CST/ SUNDAY FOR
MIZ001>005-009-084.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...KLUBER
AVIATION...TITUS
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
651 AM EST SAT DEC 26 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 552 AM EST SAT DEC 26 2015
WATER VAPOR IMAGERY AND RAP ANALYSIS SHOW A SRN STREAM TROF OVER THE
ROCKIES WITH SW FLOW DOWNSTREAM INTO THE UPPER GREAT LAKES. TO THE N
IN THE NRN STREAM...A BROADER TROF COVERS MUCH OF CANADA. TIGHTENING
CONFLUENT FLOW BTWN THE 2 BRANCHES IS SETTING UP A STRENGTHENING
UPPER JET IN THE VCNTY OF THE UPPER GREAT LAKES INTO SE CANADA.
MEANWHILE...SHORTWAVE FROM THE SRN STREAM TROF IS EJECTING NE ACROSS
THE WRN PLAINS. COMBINATION OF STRENGTHENING RIGHT ENTRANCE UPPER
JET FORCING AND EJECTING ENERGY HAS LED TO PCPN DEVELOPMENT FROM
NEBRASKA NE INTO ECNTRL MN.
INHERITED FCST IS GENERALLY ON TRACK...BUT SOME REFINEMENTS HAVE
BEEN NEEDED. STRENGTHENING FGEN IN RESPONSE TO STRENGTHENING UPPER
JET AND SHARPENING ISOTACH GRADIENT WILL SUPPORT CONTINUED SPREAD OF
PCPN NE INTO THE UPPER GREAT LAKES TODAY. THE MOST ACTIVE FGEN
RESPONSE/STRENGTHENING IS A BIT HIGHER INTO THE MID LEVELS THAN
TYPICALLY SEEN SO THE HEAVIER BAND OF SNOW WILL BE DISPLACED QUITE A
BIT FARTHER N OF THE SFC/850MB FRONT THAN ONE WOULD NORMALLY SEE.
BIGGEST CONCERN THIS MORNING IS LOW-LEVEL EASTERLY FLOW HOLDING IN
DRIER AIR AT THE LOW LEVELS ACROSS CNTRL AND ERN UPPER MI. MOST OF
THE 00Z HIGH RES MODEL GUIDANCE HAS MAINTAINED ENOUGH DRY AIR TO
SHIFT MAIN AREA OF SNOW A BIT W AND N OF WHAT WAS PREVIOUSLY
EXPECTED. HOURLY RAP/HRRR MODEL RUNS THRU THE NIGHT HAVE CONTINUED
TO MAINTAIN OR EVEN STRENGTHEN THE LOW LEVEL DRY AIR AS HAS THE 06Z
NAM. AS A RESULT...THIS MORNINGS FCST HAS TRENDED POPS/HEAVIEST SNOW
A BIT W AND N...RESULTING IN IRON COUNTY WINTER WX ADVY BEING
DROPPED. MARQUETTE COUNTY COULD SEE QUITE A GRADIENT FROM SE TO NW
TODAY...WITH POTENTIAL FOR AREAS S AND E OF MARQUETTE TO SEE LITTLE
OR NOTHING WHILE SEVERAL INCHES OF SNOW FALL N AND W OF NEGAUNEE.
FARTHER W AND NW...LOOKS LIKE A SOLID ADVY SNOWFALL TODAY OF 3-6
INCHES. BIGGEST CONCERN IS THE KEWEENAW WHERE SOME LAKE ENHANCEMENT
COULD OCCUR UNDER ENE LOW-LEVEL WINDS...POTENTIALLY REQUIRING
UPGRADING OF HEADLINE. WILL NEED TO MONITOR SNOW TRENDS AFTER
SYNOPTIC SNOW ARRIVES TO SEE WHERE OR IF ENHANCEMENT TAKES SHAPE.
LATE THIS AFTN/EVENING...PCPN SHOULD EXPAND ACROSS THE CNTRL AND ERN
FCST AREA AS A PUSH OF STRONGER ISENTROPIC ASCENT/MOISTURE ADVECTION
SHIFTS ACROSS THE AREA. PCPN DURATION SHOULD BE BRIEF ENOUGH TO
PRECLUDE ANY NEED FOR HEADLINES ACROSS THE SCNTRL/E WITH ONLY 1-2
INCHES OF SNOW. CLOSE TO LAKE MI IN MENOMINEE COUNTY...PCPN MAY MIX
WITH RAIN FOR A TIME. BACK TO WRN AND NCNTRL UPPER MI...SYNOPTIC
SNOW WILL WIND DOWN...BUT LAKE/UPSLOPE ENHANCEMENT SHOULD SUPPORT AS
MUCH AS 3-4 INCHES OF ADDITIONAL SNOW IN THE FAVORED HIGH TERRAIN
AREAS AS WINDS BACK FROM NE TO N.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 459 AM EST SAT DEC 26 2015
A SIGNIFICANT LARGE-SCALE PATTERN CHANGE WILL BE UNDERWAY AT THE
START OF THE FORECAST PERIOD AS DEEP TROUGHING DEVELOPS ACROSS THE
CENTRAL CONUS FOR THE UPCOMING WEEK.
SUNDAY...SHORTWAVE TROUGHING OVER THE UPPER MS VALLEY WILL BE
SHIFTING EASTWARD WHILE PHASING WITH A PIECE OF ENEGERY THAT EJECTED
FROM A CLOSED LOW OVER THE SW STATES. WITH SYNOPTIC MOISTURE FROM
TODAYS SYSTEM HAVING ALREADY DEPARTED...PRECIP WILL BE CONFINED TO
LES ALONG LAKE SUPERIOR. WITH INVERSIONS LOWERING TO UNDER 4KFT AND
DEEP DRY AIR ADVECTING ACROSS THE UPPER GREAT LAKES...DO NOT EXPECT
ANY INTENSE LES. RATHER...THE SHALLOW CLOUD MOSTLY LOCATED WITHIN
THE DGZ SUPPORTS PERIODS OF LIGHT TO INFREQUENTLY MODERATE FLUFFY
LES FOR MAINLY THE NW-WIND SNOW BELTS...ESPECIALLY EAST WHERE LOW-
LEVEL CONV IS ENHANCED BY A LINGERING LOW-LEVEL THERMALLY INDUCED
TROUGH OVER LAKE SUPERIOR.
SUNDAY NIGHT THROUGH TUESDAY...MODEL GUIDANCE HAS HAD SOME SERIOUS
STRUGGLES WITH HOW TO HANDLE THE CUTOFF LOW OVER THE SW STATES. 24
HOURS AGO...GUIDANCE WAS TRENDING TOWARD SENDING THE LOW WELL TO THE
SE. NOW...NEARLY THE WHOLE MODEL SUITE HAS SHIFTED WELL TO THE NW.
THE SFC LOW IS NOW PROGGED TO TRACK ACROSS THE UPPER GREAT LAKES
MONDAY NIGHT INTO TUESDAY MORNING.
AS THE SFC LOW APPROACHES...LES ALONG LAKE SUPERIOR WILL SHIFT TO
THE NE WIND BELTS BY DAYBREAK MONDAY...AND THE EAST WIND BELTS BY
MONDAY AFTERNOON. SIGNIFICANT LOW LEVEL DRYING ASSOCIATED WITH A
STRONG 1040 MB HIGH OVER ONTARIO WILL LIKELY LIMIT LES ACTIVITY TO
JUST SOME ISOLATED TO SCATTERED LIGHT SHOWERS.
THE BEST FORCING FROM COUPLED UPPER JET STREAKS AND MID-LEVEL Q-
VECTOR CONV ARE STILL FORECAST TO REMAIN SOUTHEAST OF THE CWA...BUT
A MODEST DEFORMATION BAND ON THE NW SIDE OF THE WILL HAVE THE
POTNETIAL TO BRING SEVERAL INCHES OF ACCUMULATING SNOW ACROSS THE
CWA MONDAY NIGHT INTO EARLY TUESDAY MORNING. THE AFFORMENTED DRY NE
FLOW OFF ONTARIO WILL LIKELY LIMIT SNOWFALL TOTALS...SO DO NOT SEE
ANYTHING MORE THAN AN ADVISORY-LEVEL SNOW AT THIS TIME.
EAST WINDS WILL QUICKLY INCREASE ON MONDAY WITH THE TIGHTENING
PRESSURE GRADIENT BETWEEN THE APPROACHING LOW AND ONTARIO HIGH.
EXPOSED LOCATIONS TO EAST WINDS ALONG THE GREAT LAKES AND HIGH
TERRAIN SHOULD EXPERIENCE FREQUENT GUSTS TO 35 MPH LATE IN THE
AFTERNOON AND WELL INTO MONDAY NIGHT.
WEDNESDAY THROUGH FRIDAY...A PAIR OF MID-LEVEL TROUGHS ARE SET TO
CROSS THE UPPER GREAT LAKES ON WEDNESDAY AND THURSDAY. WITH RATHER
BROAD FORCING AND LIMITED MOISTURE...NEITHER LOOK TO BRING MORE THAN
A COUPLE INCHES OF SNOW. LES FOR THE NW WIND SNOW BELTS THEN
DEVELOPS BEHIND THESE TROUGHS ON FRIDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 651 AM EST SAT DEC 26 2015
AREA OF SNOW SPREADING INTO THE UPPER GREAT LAKES WILL AFFECT
KIWD/KCMX MORE SO THAN KSAW TODAY. AT KIWD/KCMX...EXPECT CONDITIONS
TO DETERIORATE TO IFR THIS MORNING. NOT OUT OF THE QUESTION FOR LIFR
CONDITIONS TO DEVELOP AS WELL...ESPECIALLY AT KCMX WHERE EASTERLY
WIND MAY LAKE ENHANCE THE SNOW. AT KSAW...MVFR CONDITIONS SHOULD
PREVAIL TODAY WITH SOME -SN AT TIMES. TONIGHT...IFR CONDITIONS
SHOULD PERSIST AT KIWD/KCMX WITH KSAW ALSO FALLING TO IFR AS BACKING
WINDS LEAD TO UPSLOPING AND LAKE ENHANCEMENT.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 552 AM EST SAT DEC 26 2015
E TO NE WINDS WILL INCREASE TODAY UNDER TIGHTENING PRES GRADIENT
BTWN HIGH PRES RIDGE LIFTING N INTO NRN ONTARIO AND LOW PRES TROF
ORGANIZING FROM THE SRN PLAINS TO THE LOWER LAKES. EXPECT WINDS OF
20-30KT OVER WRN LAKE SUPERIOR AND 15-25KT ACROSS THE E. WINDS WILL
DIMINISH A LITTLE TONIGHT BEFORE INCREASING AGAIN ON SUN...THIS TIME
OVER ERN LAKE SUPERIOR WHERE WINDS WILL REACH 20-30KT. HEADING INTO
MON/MON NIGHT...LATEST INDICATIONS ARE FOR A WEAKENING LOW PRES
SYSTEM TO LIFT INTO THE GREAT LAKES WHILE STRONG HIGH PRES RESIDES N
AND NE OF LAKE SUPERIOR. THIS SHOULD RESULT IN A PERIOD OF EASTERLY
GALES DEVELOPING MON/MON EVENING. WINDS WILL THEN DIMINISH TUE AND
BECOME LIGHT...MAINLY UNDER 15KT ON WED.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 10 AM EST SUNDAY FOR MIZ004-005.
WINTER WEATHER ADVISORY UNTIL 10 AM EST /9 AM CST/ SUNDAY FOR
MIZ001>003-009-084.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...KLUBER
AVIATION...ROLFSON
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
552 AM EST SAT DEC 26 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 552 AM EST SAT DEC 26 2015
WATER VAPOR IMAGERY AND RAP ANALYSIS SHOW A SRN STREAM TROF OVER THE
ROCKIES WITH SW FLOW DOWNSTREAM INTO THE UPPER GREAT LAKES. TO THE N
IN THE NRN STREAM...A BROADER TROF COVERS MUCH OF CANADA. TIGHTENING
CONFLUENT FLOW BTWN THE 2 BRANCHES IS SETTING UP A STRENGTHENING
UPPER JET IN THE VCNTY OF THE UPPER GREAT LAKES INTO SE CANADA.
MEANWHILE...SHORTWAVE FROM THE SRN STREAM TROF IS EJECTING NE ACROSS
THE WRN PLAINS. COMBINATION OF STRENGTHENING RIGHT ENTRANCE UPPER
JET FORCING AND EJECTING ENERGY HAS LED TO PCPN DEVELOPMENT FROM
NEBRASKA NE INTO ECNTRL MN.
INHERITED FCST IS GENERALLY ON TRACK...BUT SOME REFINEMENTS HAVE
BEEN NEEDED. STRENGTHENING FGEN IN RESPONSE TO STRENGTHENING UPPER
JET AND SHARPENING ISOTACH GRADIENT WILL SUPPORT CONTINUED SPREAD OF
PCPN NE INTO THE UPPER GREAT LAKES TODAY. THE MOST ACTIVE FGEN
RESPONSE/STRENGTHENING IS A BIT HIGHER INTO THE MID LEVELS THAN
TYPICALLY SEEN SO THE HEAVIER BAND OF SNOW WILL BE DISPLACED QUITE A
BIT FARTHER N OF THE SFC/850MB FRONT THAN ONE WOULD NORMALLY SEE.
BIGGEST CONCERN THIS MORNING IS LOW-LEVEL EASTERLY FLOW HOLDING IN
DRIER AIR AT THE LOW LEVELS ACROSS CNTRL AND ERN UPPER MI. MOST OF
THE 00Z HIGH RES MODEL GUIDANCE HAS MAINTAINED ENOUGH DRY AIR TO
SHIFT MAIN AREA OF SNOW A BIT W AND N OF WHAT WAS PREVIOUSLY
EXPECTED. HOURLY RAP/HRRR MODEL RUNS THRU THE NIGHT HAVE CONTINUED
TO MAINTAIN OR EVEN STRENGTHEN THE LOW LEVEL DRY AIR AS HAS THE 06Z
NAM. AS A RESULT...THIS MORNINGS FCST HAS TRENDED POPS/HEAVIEST SNOW
A BIT W AND N...RESULTING IN IRON COUNTY WINTER WX ADVY BEING
DROPPED. MARQUETTE COUNTY COULD SEE QUITE A GRADIENT FROM SE TO NW
TODAY...WITH POTENTIAL FOR AREAS S AND E OF MARQUETTE TO SEE LITTLE
OR NOTHING WHILE SEVERAL INCHES OF SNOW FALL N AND W OF NEGAUNEE.
FARTHER W AND NW...LOOKS LIKE A SOLID ADVY SNOWFALL TODAY OF 3-6
INCHES. BIGGEST CONCERN IS THE KEWEENAW WHERE SOME LAKE ENHANCEMENT
COULD OCCUR UNDER ENE LOW-LEVEL WINDS...POTENTIALLY REQUIRING
UPGRADING OF HEADLINE. WILL NEED TO MONITOR SNOW TRENDS AFTER
SYNOPTIC SNOW ARRIVES TO SEE WHERE OR IF ENHANCEMENT TAKES SHAPE.
LATE THIS AFTN/EVENING...PCPN SHOULD EXPAND ACROSS THE CNTRL AND ERN
FCST AREA AS A PUSH OF STRONGER ISENTROPIC ASCENT/MOISTURE ADVECTION
SHIFTS ACROSS THE AREA. PCPN DURATION SHOULD BE BRIEF ENOUGH TO
PRECLUDE ANY NEED FOR HEADLINES ACROSS THE SCNTRL/E WITH ONLY 1-2
INCHES OF SNOW. CLOSE TO LAKE MI IN MENOMINEE COUNTY...PCPN MAY MIX
WITH RAIN FOR A TIME. BACK TO WRN AND NCNTRL UPPER MI...SYNOPTIC
SNOW WILL WIND DOWN...BUT LAKE/UPSLOPE ENHANCEMENT SHOULD SUPPORT AS
MUCH AS 3-4 INCHES OF ADDITIONAL SNOW IN THE FAVORED HIGH TERRAIN
AREAS AS WINDS BACK FROM NE TO N.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 459 AM EST SAT DEC 26 2015
A SIGNIFICANT LARGE-SCALE PATTERN CHANGE WILL BE UNDERWAY AT THE
START OF THE FORECAST PERIOD AS DEEP TROUGHING DEVELOPS ACROSS THE
CENTRAL CONUS FOR THE UPCOMING WEEK.
SUNDAY...SHORTWAVE TROUGHING OVER THE UPPER MS VALLEY WILL BE
SHIFTING EASTWARD WHILE PHASING WITH A PIECE OF ENEGERY THAT EJECTED
FROM A CLOSED LOW OVER THE SW STATES. WITH SYNOPTIC MOISTURE FROM
TODAYS SYSTEM HAVING ALREADY DEPARTED...PRECIP WILL BE CONFINED TO
LES ALONG LAKE SUPERIOR. WITH INVERSIONS LOWERING TO UNDER 4KFT AND
DEEP DRY AIR ADVECTING ACROSS THE UPPER GREAT LAKES...DO NOT EXPECT
ANY INTENSE LES. RATHER...THE SHALLOW CLOUD MOSTLY LOCATED WITHIN
THE DGZ SUPPORTS PERIODS OF LIGHT TO INFREQUENTLY MODERATE FLUFFY
LES FOR MAINLY THE NW-WIND SNOW BELTS...ESPECIALLY EAST WHERE LOW-
LEVEL CONV IS ENHANCED BY A LINGERING LOW-LEVEL THERMALLY INDUCED
TROUGH OVER LAKE SUPERIOR.
SUNDAY NIGHT THROUGH TUESDAY...MODEL GUIDANCE HAS HAD SOME SERIOUS
STRUGGLES WITH HOW TO HANDLE THE CUTOFF LOW OVER THE SW STATES. 24
HOURS AGO...GUIDANCE WAS TRENDING TOWARD SENDING THE LOW WELL TO THE
SE. NOW...NEARLY THE WHOLE MODEL SUITE HAS SHIFTED WELL TO THE NW.
THE SFC LOW IS NOW PROGGED TO TRACK ACROSS THE UPPER GREAT LAKES
MONDAY NIGHT INTO TUESDAY MORNING.
AS THE SFC LOW APPROACHES...LES ALONG LAKE SUPERIOR WILL SHIFT TO
THE NE WIND BELTS BY DAYBREAK MONDAY...AND THE EAST WIND BELTS BY
MONDAY AFTERNOON. SIGNIFICANT LOW LEVEL DRYING ASSOCIATED WITH A
STRONG 1040 MB HIGH OVER ONTARIO WILL LIKELY LIMIT LES ACTIVITY TO
JUST SOME ISOLATED TO SCATTERED LIGHT SHOWERS.
THE BEST FORCING FROM COUPLED UPPER JET STREAKS AND MID-LEVEL Q-
VECTOR CONV ARE STILL FORECAST TO REMAIN SOUTHEAST OF THE CWA...BUT
A MODEST DEFORMATION BAND ON THE NW SIDE OF THE WILL HAVE THE
POTNETIAL TO BRING SEVERAL INCHES OF ACCUMULATING SNOW ACROSS THE
CWA MONDAY NIGHT INTO EARLY TUESDAY MORNING. THE AFFORMENTED DRY NE
FLOW OFF ONTARIO WILL LIKELY LIMIT SNOWFALL TOTALS...SO DO NOT SEE
ANYTHING MORE THAN AN ADVISORY-LEVEL SNOW AT THIS TIME.
EAST WINDS WILL QUICKLY INCREASE ON MONDAY WITH THE TIGHTENING
PRESSURE GRADIENT BETWEEN THE APPROACHING LOW AND ONTARIO HIGH.
EXPOSED LOCATIONS TO EAST WINDS ALONG THE GREAT LAKES AND HIGH
TERRAIN SHOULD EXPERIENCE FREQUENT GUSTS TO 35 MPH LATE IN THE
AFTERNOON AND WELL INTO MONDAY NIGHT.
WEDNESDAY THROUGH FRIDAY...A PAIR OF MID-LEVEL TROUGHS ARE SET TO
CROSS THE UPPER GREAT LAKES ON WEDNESDAY AND THURSDAY. WITH RATHER
BROAD FORCING AND LIMITED MOISTURE...NEITHER LOOK TO BRING MORE THAN
A COUPLE INCHES OF SNOW. LES FOR THE NW WIND SNOW BELTS THEN
DEVELOPS BEHIND THESE TROUGHS ON FRIDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1210 AM EST SAT DEC 26 2015
MVFR CLOUDS AT ALL TAF SITES OVERNIGHT ARE EXPECTED TO LOWER TO
IFR/LIFR TODAY AS A BAND OF SNOW MOVES INTO THE AREA AND LAKE
ENHANCEMENT COMMENCES. NOT PRECISELY SURE WHERE HEAVIEST SNOW/LOWER
VIS WILL BE...BUT SHOULD SEE LOW CIGS/VIS AT ALL SITES...WITH THE
POTENTIAL FOR HEAVY SNOW.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 552 AM EST SAT DEC 26 2015
E TO NE WINDS WILL INCREASE TODAY UNDER TIGHTENING PRES GRADIENT
BTWN HIGH PRES RIDGE LIFTING N INTO NRN ONTARIO AND LOW PRES TROF
ORGANIZING FROM THE SRN PLAINS TO THE LOWER LAKES. EXPECT WINDS OF
20-30KT OVER WRN LAKE SUPERIOR AND 15-25KT ACROSS THE E. WINDS WILL
DIMINISH A LITTLE TONIGHT BEFORE INCREASING AGAIN ON SUN...THIS TIME
OVER ERN LAKE SUPERIOR WHERE WINDS WILL REACH 20-30KT. HEADING INTO
MON/MON NIGHT...LATEST INDICATIONS ARE FOR A WEAKENING LOW PRES
SYSTEM TO LIFT INTO THE GREAT LAKES WHILE STRONG HIGH PRES RESIDES N
AND NE OF LAKE SUPERIOR. THIS SHOULD RESULT IN A PERIOD OF EASTERLY
GALES DEVELOPING MON/MON EVENING. WINDS WILL THEN DIMINISH TUE AND
BECOME LIGHT...MAINLY UNDER 15KT ON WED.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 10 AM EST SUNDAY FOR MIZ004-005.
WINTER WEATHER ADVISORY UNTIL 10 AM EST /9 AM CST/ SUNDAY FOR
MIZ001>003-009-084.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...KLUBER
AVIATION...VOSS
MARINE...ROLFSON
AREA FORECAST DISCUSSION
National Weather Service Kansas City/Pleasant Hill MO
800 PM CST SUN DEC 27 2015
.UPDATE...
Issued at 800 PM CST SUN DEC 27 2015
Taking a look at 00Z sounding data shows a very pronounced warm nose
over southern Missouri, but lower in the atmosphere than models had
predicted it to be (peaks out at 850 hPa instead of 800 hPa). Wind
flow lower in the atmosphere favors this warm air to spread more
north-northeast instead of the north-northwest trajectories further
up aloft. This could delay the onset of warm air aloft over western
MO and northeast KS, so that the transition from snow and sleet over
to freezing rain may not occur across the I-35 corridor until 12Z or
later, after several hours of mostly snow and a little sleet could
accumulate to several inches. RAP has been hinting at this colder
possibility and new NAM trickling in seems to be trending much colder
aloft as well. Will likely need to increase snow/sleet amounts quite
a bit for the I-35 corridor and points northwest, where 3" to 8" of
snow isn`t out of the realm of possibility. Further complicating
things is the fact that precipitation may obtain a convective element
toward sunrise, right as the precipitation changeover is occurring.
If this leads to thundersnow, as could happen just northwest of KC,
this could lead to snow rates of 2" per hour or greater, but if it`s
falling as sleet (or even graupel/hail) that will cut back on snow
amounts quite a bit. Will continue to watch model data trickle in but
a new forecast to increase snow amounts near and northwest of I-35
will likely be coming out shortly.
&&
.SHORT TERM...(This Evening through Tuesday Afternoon)
Issued at 331 PM CST SUN DEC 27 2015
A complex winter storm is still on track to impact the area this
evening through Monday night as low pressure lifts out the southern
High Plains and into the forecast area. Model agreement is much
higher on the overall track of the system; however, there are still
significant differences in the temperature profile from the surface
through the depth of the column, which impacts precipitation type
and result in still a range of forecast possibilities, especially
over the KC metro area.
Rain showers will continue to lift northward tonight in response to
the ejecting system, reaching the KC area between 9 PM and midnight,
and the northern CWA border by 3 AM. Surface temperatures currently
range from around 30 degrees in northwest MO to the mid 30s across
central MO, and will likely change little due to the battle between
strong cold air advection and progressively warming temperatures
aloft. As a result, some freezing rain will become possible as
showers move over subfreezing temperatures, and could initially mix
with sleet as the column saturates. Precipitation will eventually
meet and cross the freezing line aloft, resulting in more sleet and
perhaps some snow on the northern border of the precip shield as it
lifts northward early Monday morning. The warm nose centered around
800 hPa will continue to surge northward; however, resulting in
mixed precipitation and at least a short period of freezing rain
across much of the northwestern half to third of the CWA. The NAM is
by far the most aggressive solution for freezing rain accumulation
and appears to be an outlier with its nearly +8 to +9 warm nose, but
if it verifies, could mean quite a bit more ice than is currently
forecast mainly from Kansas City northwestward. In contrast, the GFS
and EC do not feature as strong of a warm nose and keep the surface
freezing line closer to the freezing line aloft -- making for a more
linear solution of rain in the warm sector and sleet/snow in the
cold sector, and lower ice amounts than the forecast currently
indicates especially for KC. Conceptually, it appears that the
highest threat for ice accumulation will be in areas that are
already several degrees below freezing this afternoon, which is
mainly the far northwest side of the KC metro up to the St. Joseph
area, before colder temperatures aloft reduce the probability of
liquid precipitation.
All models show some surface warming as the low lifts up, bringing
temperatures to or slightly above 32 degrees by late Monday morning,
which would end the freezing rain threat before the changeover to
snow occurs Monday afternoon. Even the NAM has a period of all rain
for all but extreme northwest and northern MO after sunrise Monday,
melting some or all of the ice accumulation and possibly reducing
some of the travel impacts for the late morning and early afternoon.
Regardless, liquid precipitation will gradually transition to snow
from west to east as the surface low moves east of the forecast
area, and should bring quite a bit of snow to far northwest MO where
the changeover will happen earliest and be coincident with the most
precipitation equivalent. Almost 10 inches of storm total snow is
possible in our northwest corner where the deformation zone will be
best defined, tapering off very quickly to less than 4 inches in St.
Joseph and to an inch or less from KC to Kirksville where the
transition will occur after the precipitation rates have begun to
taper off.
Winds will also be extremely strong on the northeast side of the
surface low tonight into tomorrow morning, likely reaching advisory
criteria throughout the entire forecast area after 03z tonight, and
further complicating ice accumulation should it occur late tonight
through Monday morning. Based on this forecast, have opted to trim
off the southeast side of the winter storm warning where surface
temperatures may stay too warm, and continue it elsewhere. The
southeast gradient of the warning may not reach true warning
criteria, but potential for significant sleet accumulation and the
combination of strong winds and freezing rain during the early
morning hours, especially on a work/holiday travel day, warranted a
continuation of the warning in those areas. A wind advisory will be
issued elsewhere.
A full transition to snow is expected before the system fully exits
the area, giving almost the entire CWA a light dusting as it
departs. All snow should be out of the region by Tuesday morning.
.LONG TERM...(Tuesday Evening through Sunday)
Issued at 331 PM CST SUN DEC 27 2015
On the heels of the winter storm in the early week, an embedded
shortwave ejecting off of a broad, weakening trough over the western
CONUS may produce additional wintry activity by Wednesday. The
uncertainties with this feature are the availability of moisture in
the wake of the exiting storm system along with the speed at which
it crosses through the region ahead of a building ridge to the west.
Should any precipitation develop, the thermal profile will be well
supportive of all snow. The question that will need to be addressed
is how much, all dependent on moisture availability. Areas that look
to be impacted as of now include northeast Kansas and northwest
Missouri, coincident with areas to be impacted on Monday with the
winter storm system.
Beyond this activity, the active weather pattern should subside
through the remainder of the week as a building ridge will maintain
dry conditions heading into the weekend. The cold air mass will
remain firmly in place with afternoon highs likely remaining below
freezing for the remainder of the week, with overnight lows dipping
into the teens for most of the CWA, and single digits for northwest
Missouri. Temperatures should recover a bit late into the weekend as
the building ridge moves eastward.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday Evening)
Issued at 550 PM CST SUN DEC 27 2015
High Impact Winter Storm on track for tonight through Monday
evening...Freezing precipitation...mostly ice pellets and snow grains
will move into the area tonight after around 04Z...from the south as
a very strong winter storm tracks out of Texas. Freezing precip
will continue through the night and may include some liquid rain and
low visibility at times in the early morning especially at KMKC and
KIXD...but cold air in low levels is through around 6.5K feet...so
liquid may freeze by the time it reaches the ground...so most likely
type will be sleet. As colder air works in during the late morning
and into the afternoon...the sleet may change over to snow before
ending around 00Z Tuesday.
&&
.EAX Watches/Warnings/Advisories...
KS...Wind Advisory until noon CST Monday for KSZ060.
Winter Storm Warning until 9 PM CST Monday for KSZ025-057-
102>105.
MO...Wind Advisory until noon CST Monday for MOZ024-025-031>033-
038>040-043>046-053-054.
Winter Storm Warning until 9 PM CST Monday for MOZ001>008-
011>017-020>023-028>030-037.
&&
$$
UPDATE...Hawblitzel
SHORT TERM...Laflin
LONG TERM...Welsh
AVIATION...Adolphson
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1147 PM CST FRI DEC 25 2015
.UPDATE:
Issued at 825 PM CST Fri Dec 25 2015
Very little change made to the forecast other than to tweak sky
cover. After examining the 00z NAM and most recent HRRR and RAP
versus current satellite and radar trends, we still anticipate the
currently pcpn echo-free radar to rapidly fill in for most of our
forecast area late tonight and Saturday morning, of which trends
were handled well by the previous forecast.
Temps will likely bottom out and hit their min values this evening
with a slow rise overnight as clouds thicken and dewpoints rise.
TES
&&
.SHORT TERM: (Through Late Tonight)
Issued at 335 PM CST Fri Dec 25 2015
Currently experiencing the calm before the storm across the CWA
with high pressure to our north bringing tranquil conditions and
above average temperatures. Main activity at this time is the
frontal boundary draped from the TN Valley into lower MS Valley.
All indications are that fall heights and surface pressure tonight
across the high Plains along with the eastward retreat of the
surface high to our north will allow for a sizable response in
the atmosphere. Low level flow above the boundary layer is
forecast to veer and strengthen, with a veering 30-40+ kt south-
southwesterly LLJ transporting anomalously deep moisture northward
into the area while the surface boundary gradually retreats
northward as well. Precipitation should develop in response
although it appears to be delayed until overnight. The best threat
appears to be after 08-09z when elevated showers and thunderstorms
are expected primarily south of I-70 across southern MO into SW
IL.
Glass
.LONG TERM: (Saturday through Next Friday)
Issued at 335 PM CST Fri Dec 25 2015
...Very Serious-High Impact and Potentially Historic Heavy Rain/Flood
Event Likely Saturday Afternoon into Monday...
High Points...
Confidence is growing and high at this point in time that a very
serious high-impact and potentially historic heavy rain/flood
event will occur in the Saturday night into Monday. This event
will feature life-threatening flash flooding on creeks/streams and
poor drainage areas, and major to historic flooding on area
rivers. The Meramec River is a huge concern.
Widespread area average storm total rainfall is now forecast in the
5-8 inch range across the southeast half of the CWA. The Bullseye
for heaviest rainfall would be late Saturday afternoon and Saturday
night with embedded convection/high rainfall rates and training,
however this will also be a prolonged event lasting well into
Monday. A flash flood watch is already in place and we have now
expanded it northward some to account for greater northward spread
of significant precipitation during the event.
Discussion...
The rapid evolution and expansion of a wide wsw-ene oriented band
of rain and thunderstorms is expected on Saturday along and north
of the lifting frontal zone. This will be in response to strong
deep layer ascent associated with a 40+ s/swly LLJ, disturbances
with the SW flow aloft and divergence aloft within the entrance
region of an anticyclonically curved ULJ. All the models have a
strong signal just differ some on the boundary location. Prefer
a blend of the GFS/ECMWF with this aspect and QPF placement with
the front near the I-44 corridor in MO and I-70 in IL at 00z
Sunday, feeling the NAM is too far north lifting the boundary
into cooler air.
The worst of this prolonged event appears to have a bullseye on
late Saturday afternoon into Saturday night. PWs are forecast to
exceed 1.5 inches which is 5 standard deviations above normal!
Strong deep layer ascent is focused in a broad region along and
north of the surface front resulting from frontogenesis, low level
MCON/lift, upper level disturbances and the ULJ entrance region.
This focused elongated forcing and flow aloft parallel to the
frontal zone favors training with elevated instability supporting
embedded convection. Along and south of the frontal zone there
could also be a few severe storms Saturday afternoon and evening.
The front then sags southeastward late Saturday night and this
will shift some of the focus of the axis of heaviest rainfall on
Sunday to the southeast third of the CWA. Finally late Sunday into
Monday will be the last aspect of the event as a strong closed upper
low and the associated vertically stacked system lifts north/northeast
through the MS Valley. This will lead a renewed northward spread
in rain, although rates appear lower with this round. While there
are differences in the system track, the most favored is a
western track which would largely keep any wintry precipitation at
bay to the west, with some chance of snow Monday night across
northeast and central MO in the cyclonic flow/CAA in the wake of
the departing system.
Glass
&&
.AVIATION: (For the 06z TAFs through 06z Saturday Night)
Issued at 1137 PM CST Fri Dec 25 2015
MVFR clouds will spread northward over the next 0-6 hours ahead of
an approaching low pressure system. This system will bring a
prolonged period of moderate/heavy rain along with reduced cigs
and vsbys, especially after 18z. Embedded thunderstorms are also
possible, especially between 18-22z when instability values are
highest. Rain will persist through the remainder of the valid TAF
period.
Kanofsky
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...Flash Flood Watch from Saturday afternoon through Monday
afternoon 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.
IL...Flash Flood Watch from Saturday afternoon through Monday
afternoon FOR Bond IL-Calhoun IL-Clinton IL-Fayette IL-
Greene IL-Jersey IL-Macoupin IL-Madison IL-Marion IL-Monroe
IL-Montgomery IL-Pike IL-Randolph IL-St. Clair IL-
Washington IL.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
850 PM CST SUN DEC 27 2015
.UPDATE...
ISSUED AT 850 PM CST SUN DEC 27 2015
NO CHANGES THIS EVENING TO THE PREVIOUS THINKING...WILL LET THE
HEADLINES STAY AS IS.
SOME OBSERVATIONS FROM THE 00Z UPPER AIR DATA. THE KOAX SOUNDING
ONLY HAD A PW OF 0.08 INCHES...WHICH WAS DOWN FROM 0.20 AT 12Z.
MOISTURE WAS MUCH BETTER TO THE SOUTH THOUGH...WITH PW AT KTOP AT
0.53 INCHES. WILL LIKELY TWEAK DOWN THE QPF JUST A BIT 06Z TO 12Z
TONIGHT IN OUR SRN COUNTIES WITH THE EVENING UPDATE.
12 HOUR HEIGHT FALLS AT 500 MB WERE HIGHEST...ABOUT 150 METERS...
JUST NORTHEAST OF KDRT IN TX. KICKER SHORTWAVE CONTINUED TO CRASH
INTO THE WRN UNITED STATES...WITH HEIGHT FALLS OF UP TO 110 METERS.
LATEST WATER VAPOR LOOP SHOWED SOME NWD MOVEMENT OF THE MID LEVEL
CLOSED CIRCULATION OVER TX. THE GENERAL CONSENSUS OF THE LATEST
AVAILABLE MODEL DATA...ECMWF/GFS/NAM/SREF/HRRR BRINGS THE CENTER
OF THE CIRCULATION TO SWRN MO BY 18Z MONDAY...THEN TO WRN IL BY
00Z TUE.
00Z NAM SHOWED A LOT LESS SNOW THAN OTHER MODELS...AND WAS NOT
PREFERRED. 00Z EXPERIMENTAL HRRR SHOWED QPF OF 0.25 TO 0.55 INCHES
ACROSS MUCH OF SERN NE AND WRN IA 12Z TO 18Z MON (0.35 TO 0.45 IN
THE OMAHA METRO). THE QPF FROM THAT SAME MODEL 18Z MON TO 00Z TUE
VARIED FROM 0.10 IN OUR FAR WRN COUNTIES TO AROUND 0.80 JUST EAST
OF POTTAWATTAMIE COUNTY IA (WITH AROUND 0.20 FOR OMAHA METRO).
&&
.SHORT TERM...(TONIGHT THROUGH WEDNESDAY)
ISSUED AT 250 PM CST SUN DEC 27 2015
TRACK AND INTENSITY OF SOUTHERN PLAINS STORM SYSTEM AND RESULTANT
SNOWFALL WILL BE THE MAIN FORECAST CHALLENGE AS THE SYSTEM LIFTS
ACROSS THE LOWER MISSOURI VALLEY ON MONDAY.
THE WINTER STORM WATCH THAT COVERED THE AREA HAS BEEN UPGRADED TO
A WINTER STORM WARNING FOR ALL BUT A FEW COUNTIES IN EXTREME
NORTHEAST NEBRASKA WHERE A WINTER WEATHER ADVISORY WILL BE IN
EFFECT ON MONDAY. THE MAJORITY OF MODELS THIS MORNING CONTINUE TO
SHOW A MAJOR WINTER STORM MOVING ACROSS THE FORECAST AREA STARTING
LATE TONIGHT AND EXTENDING INTO MONDAY NIGHT. GOOD UPPER SUPPORT
AND ABUNDANT MOISTURE WILL RESULT IN HEAVY SNOW AND GUSTY NORTH
WINDS FOR THE AREA AND WILL CREATE HAZARDOUS TRAVEL CONDITIONS
FOR THOSE FOLKS HEADING HOME AFTER THE CHRISTMAS HOLIDAY WEEKEND.
PRIMARY AXIS OF HEAVY SNOW LOOKS TO BE ORIENTED RIGHT ACROSS
EASTERN NEBRASKA INTO NORTHWEST IOWA ON MONDAY WITH PERIODS OF
SLEET AT TIMES FROM PARTS OF SOUTHWEST IOWA INTO EXTREME SOUTHEAST
NEBRASKA. THE STORM SYSTEM SHOULD MOVE ACROSS THE REGION RATHER
QUICKLY...RACING FROM SOUTHEAST OKLAHOMA ON MONDAY MORNING TO
SOUTHERN WISCONSIN BY LATE MONDAY NIGHT. DRIER MID LEVEL AIR MAY
HINDER THE APPROACHING MOISTURE FOR A TIME LATER TONIGHT BUT THE
ATMOSPHERE IS EXPECTED TO SATURATE QUICKLY AS THE STORM GETS
CLOSER TO THE AREA. MAJORITY OF SNOW ACCUMULATION WILL BE OVER BY
MONDAY EVENING ALTHOUGH LINGERING PERIODS OF LIGHT SNOW WILL
CONTINUE THROUGH MONDAY NIGHT. ANOTHER UPPER TROUGH COMING ACROSS
THE REGION TUESDAY NIGHT MAY ALSO TRIGGER SOME LIGHT SNOW IN FAR
SOUTHEAST NEBRASKA AND SOUTHWEST IOWA.
.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 250 PM CST SUN DEC 27 2015
LESS ACTIVE WEATHER BUT REMAINING COLD THROUGH THE PERIOD AS MEAN
TROUGH STAYS OVER THE EASTERN THIRD OF THE NATION AND AREA
CONTINUES UNDER THE INFLUENCE OF NORTHWEST FLOW. TODAYS MODELS
ALSO SHOW LESS RIDGE DEVELOPMENT IN THE WEST COMPARED TO
YESTERDAY.
&&
.AVIATION...(00Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 525 PM CST SUN DEC 27 2015
CLOUDS WILL THICKEN/LOWER OVERNIGHT. CONDITIONS WILL DETERIORATE
RAPIDLY AFTER 11Z BASED ON CURRENT THINKING...WITH LIFR CONDITIONS
LIKELY DEVELOPING IN THE MORNING AT KOMA AND KLNK WITH SNOW. WINDS
WILL ALSO BE ON THE INCREASE. CONDITIONS SHOULD DETERIORATE AT
KOFK AS WELL...BUT A BIT LATER AND WITH CONDITIONS MAYBE NOT QUITE
AS LOW FOR CIGS.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...WINTER STORM WARNING FROM 6 AM MONDAY TO 6 AM CST TUESDAY FOR
NEZ012-015-017-018-031>034-042>045-050>053-065>067-078.
WINTER STORM WARNING FROM 3 AM MONDAY TO MIDNIGHT CST MONDAY
NIGHT FOR NEZ068-088>093.
WINTER WEATHER ADVISORY FROM 6 AM MONDAY TO 6 AM CST TUESDAY FOR
NEZ011-016-030.
IA...WINTER STORM WARNING FROM 6 AM MONDAY TO 6 AM CST TUESDAY FOR
IAZ043-055-056-069-079.
WINTER STORM WARNING FROM 3 AM MONDAY TO MIDNIGHT CST MONDAY
NIGHT FOR IAZ080-090-091.
&&
$$
UPDATE...MILLER
SHORT TERM...FOBERT
LONG TERM...FOBERT
AVIATION...MILLER
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
331 AM CST SAT DEC 26 2015
.SYNOPSIS...
ISSUED AT 330 AM CST SAT DEC 26 2015
LEAD PV ANOMALY FROM EVOLVING POSITIVELY TITLED LONG WAVE TROUGH
OVER THE WRN STATES MOVING QUICKLY NEWD THIS MORNING INTO WRN SD.
EARLIER LIGHTNING STRIKES ACROSS C NEB HAVE DISSIPATED ALTHOUGH
STILL SOME CONVECTIVE ELEMENTS SEEN IN RADAR ECHOES ACROSS ERN
NEB. IN RESPONSE PV DESTRUCTION INCREASING FROM KS INTO NEB AND
IA WHICH WILL EVENTUALLY CHANGE THE TILT OF THE TROUGH IN THE
NEXT 24-48 HRS. ULTIMATELY THE ONGOING WINTER STORM ACROSS THE
WRN PORTION OF THE STATE FIGHTING DRY AIR WHICH HAS HELPED THE
CONVECTIVE ELEMENT OF THE STORM...BUT DECREASED THE OVERALL
COVERAGE OF THE HEAVIEST SNOW TO SMALLER FRONTOGENETIC BANDS.
SNOW HAS MOSTLY ENDED ACROSS SWRN NEB WHILE WINDS PICKING UP
ALONG THE FRONT RANGE AND PLAINS OF CO AND NWD INTO WRN NEB AND
SERN WY INDICATIVE OF A BARRIER JET ON NWRN SIDE OF LOW PRESSURE
SYSTEM.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 330 AM CST SAT DEC 26 2015
HAVE ADJUSTED THE TIMING OF THE WINTER WEATHER ADVISORY TO END
EARLIER ALONG THE INTERSTATE 80 CORRIDOR AS RADAR ECHO TRENDS AND
SHORT RANGE MODELS SUGGEST NO NEW SNOW DEVELOPMENT EXPECTED AS
THE SYSTEM MOVES NEWD THIS MORNING. ALTHOUGH FRONTOGENESIS
REMAINS STRONG IN THE MID LEVELS FROM MN SWWD INTO C NEB...DRY
AIR AND LARGE SCALE SUBSIDENCE WILL OVERTAKE THE SRN END AND SHUT
OFF THE ACCUMULATING SNOW THIS AFTERNOON ACROSS ALL BUT NRN AREAS
OF THE STATE. MEANWHILE NRN STREAM SHORT WAVE DROPS QUICKLY SEWD
ACROSS THE NRN PLAINS WHICH WILL INCREASE THE SUBSIDENCE FURTHER
NWD LATER THIS AFTERNOON ENDING THE PRECIP FOR THE REMAINDER OF
THE AREA. AS THIS OCCURS...STRONG COLD FRONT WILL PUSH QUICKLY
SEWD ACROSS THE AREA THIS MORNING AND EARLY AFTERNOON. THIS FRONT
DOES ORIGINATE FROM POLAR REGIONS AND WILL DROP TEMPS THROUGHOUT
THE DAY. HIGHS IN MOST PLACES WILL BE REACHED BEFORE NOON AND
WITH THE INCREASING WIND WILL MAKE IT FEEL MUCH COLDER AND WIND
CHILLS BELOW ZERO CAN BE EXPECTED MOST AREAS BY LATE AFTERNOON.
SOME AREAS OF BLOWING SNOW AS WELL ACROSS THE N THIS AFTERNOON AS
WINDS PICK UP. SKIES SHOULD CLEAR MOST OF THE WAY BY EARLY SUNDAY
MORNING LEADING TO VERY COLD ACTUAL TEMPS ESPECIALLY WHERE A
DEEPER SNOW PACK EXISTS.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 330 AM CST SAT DEC 26 2015
THE LONG TERM SUMMED UP...A COLD END TO 2015 CAN BE EXPECTED. A
SERIES OF LONG WAVE TROUGHS ACROSS THE HEART OF THE NATION TO
COMBINE WITH SNOWPACK ACROSS MUCH OF THE AREA RESULTING IN TEMPS
TO REMAIN WELL BELOW NORMAL. HIGHS GENERALLY IN THE TEENS AND 20S
WITH LOWS IN THE SINGLE DIGITS TO LOWER TEENS...LOCALLY A FEW
NIGHTS COULD SEE TEMPS DIP BELOW ZERO.
AN UPPER LEVEL LOW WILL TRACK ACROSS THE SOUTHERN ROCKIES SUNDAY
THEN LIFT NORTHEAST ACROSS THE PLAINS EARLY IN THE WEEK. THE GFS
CONTINUES TO BE THE FURTHEST EAST WITH THE TRACK...WHILE THE NAM
IS THE FURTHEST TO THE WEST. THE FORECAST CONTINUES TO FOLLOW A
BLEND...WHICH IS CLOSE TO THE TRACK FROM THE ECMWF. THIS RESULTS
IN SOME WRAP AROUND MOISTURE MAKING IT INTO THE CWA MONDAY INTO
MONDAY NIGHT...AND COULD LINGER INTO EARLY TUESDAY. THE TRACK
FAVORS THE HIGHEST PRECIP TO THE SOUTHEAST OF THE CWA...AND WOULD
NOT BE SURPRISE IF ONLY THE FAR EASTERN ZONES MANAGED TO MEASURE.
A CLIPPER QUICKLY FOLLOWS FOR TUESDAY INTO TUESDAY NIGHT. MOISTURE
IS LIMITED AND TOP DOWN SATURATION WILL LIMIT PRECIP REACHING THE
GROUND...THUS WILL KEEP POPS LOW.
ANOTHER CLIPPER FOR WEDNESDAY NIGHT INTO THURSDAY. MODELS ARE IN
AGREEMENT WITH LESS MOISTURE TO WORK WITH AND FORECAST WILL REMAIN
DRY AT THIS TIME.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1129 PM CST FRI DEC 25 2015
IFR/LOCAL LIFR IN SNOW AND LOW CIGS IS EXPECTED TONIGHT THROUGH
15Z SATURDAY...MAINLY NORTH OF INTERSTATE 80 TO THE SD BORDER.
MVFR/VFR CIGS ARE EXPECTED SATURDAY FROM 18Z ONWARD. THE MVFR IS
MOST LIKELY ALONG AND NORTH OF HIGHWAY 20.
MVFR/VFR CIGS ARE EXPECTED SATURDAY EVENING THROUGH 06Z.
CONFIDENCE IS GOOD AND THE RAP AND NAM MODELS WERE THE BASIS FOR
THE FORECAST.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL 6 PM CST /5 PM MST/ THIS EVENING FOR
NEZ004>007-094.
WINTER WEATHER ADVISORY UNTIL NOON CST /11 AM MST/ TODAY FOR
NEZ056-057-059.
WINTER WEATHER ADVISORY UNTIL 6 PM CST /5 PM MST/ THIS EVENING
FOR NEZ008>010-022>029-035>038.
&&
$$
SYNOPSIS...STOPPKOTTE
SHORT TERM...STOPPKOTTE
LONG TERM...MASEK
AVIATION...CDC
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
1130 PM CST FRI DEC 25 2015
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 258 PM CST FRI DEC 25 2015
STORM SYSTEM TO AFFECT THE AREA IS ON TRACK FOR TONIGHT INTO
SATURDAY. LATE THIS AFTERNOON...WATER VAPOR IMAGERY INDICATES THE PV
ANOMALY LOCATED OVER GRAND JUNCTION IN WESTERN COLORADO. MODELS
AGREE THAT THE ANOMALY WILL MOVE EAST-NORTHEAST INTO WESTERN
NEBRASKA THIS EVENING. A STRONG JET STREAK WILL MOVE NORTHEAST
ACROSS KANSAS INTO EASTERN NEBRASKA AHEAD OF THE SYSTEM TONIGHT. A
CROSS SECTION FROM NORTHWEST TO SOUTHEAST ACROSS THE REGION SHOWS A
CLASSIC AGEOSTROPHIC RESPONSE AS THE JET STREAK MOVES ACROSS...WITH
DEEP LIFT ACROSS MOST OF THE AREA. CONCERNS WITH SATURATION IN THE
MID LEVELS OF THE ATMOSPHERE ACROSS SOUTHWEST INTO PORTIONS OF
CENTRAL NEBRASKA...BUT THAT WILL NOT BE AN ISSUE ACROSS THE
PANHANDLE INTO NORTH CENTRAL NEBRASKA.
SNOW SHOULD INCREASE RAPIDLY ACROSS THE PANHANDLE INTO NORTH CENTRAL
NEBRASKA TONIGHT...AND CURRENT HEADLINES FOR WINTER WEATHER ADVISORY
AND WINTER STORM WARNING LOOK GOOD. DID EXPAND THE WARNING INTO BOYD
COUNTY...BUT OTHERWISE NO CHANGES.
AS MENTIONED MID LEVEL DRY AIR WILL ADVECT INTO SOUTHWEST AND
CENTRAL NEBRASKA...SO NOT EXPECTING AS MUCH SNOW IN THESE AREAS.
COULD HAVE SOME LIGHT FREEZING DRIZZLE HOWEVER.
SATURDAY MORNING A STRONG ARCTIC COLD FRONT WILL MOVE SOUTH THROUGH
THE AREA. H850MB WINDS INCREASE THROUGH THE DAY TO AROUND 45 KTS BY
AFTERNOON. BLOWING SNOW WILL LIKELY BE AN ISSUE ACROSS NORTH CENTRAL
NEBRASKA AND INTO THE PANHANDLE...AS NORTH WIND GUSTS OVER 30 MPH
ARE LIKELY. OTHERWISE FALLING TEMPERATURES THROUGH THE TEENS
EXPECTED.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 258 PM CST FRI DEC 25 2015
VERY COLD TEMPERATURES ARE LIKELY BY SUNDAY MORNING WITH LOWS IN THE
SINGLE DIGITS ABOVE ZERO CENTRAL AND SOUTHWEST NEBRASKA AND THE
SINGLE DIGITS BELOW ZERO IN THE NORTHERN SANDHILLS AND THE NEBRASKA
PANHANDLE. COMPARABLE TEMPERATURES ARE EXPECTED AGAIN SUNDAY NIGHT
AND EARLY MONDAY.
THERE IS STILL CONSIDERABLE UNCERTAINTY REGARDING THE IMPACT OF THE
MONDAY-TUESDAY SYSTEM ON CENTRAL AND WESTERN NEBRASKA. THE NAM12 IS
ABOUT 4 DEGREES LONGITUDE FARTHER WEST THAN THE GFS40 WITH THE TRACK
OF THE CYCLONE. THIS DIFFERENCE IS SIGNIFICANT WITH THE MORE
WESTERLY TRACK GIVING ISENTROPIC UPGLIDE OVER THE COLD DOME REACHING
THE NEBRASKA SANDHILLS WHILE THE MORE EASTERLY TRACK LEAVING CENTRAL
AND WESTERN NEBRASKA OUT OF THE PRECIPITATION COMPLETELY. ACCOUNTING
FOR THE UNCERTAINTY...WE WILL KEEP THE PROBABILITY LOW. AGAIN...
SIGNIFICANT DIFFERENCES IN THE EXTENDED SOLUTIONS CONTINUE EVEN
THROUGH TUESDAY NIGHT. THE ECMWF TAKES THE CYCLONE ALMOST DUE NORTH
INTO NORTHERN IOWA BEFORE TURNING IT EAST. AS A RESULT...SOME CHANCE
OF SNOWFALL WILL CONTINUE UNTIL TUESDAY EVENING IN NORTHERN
NEBRASKA.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1129 PM CST FRI DEC 25 2015
IFR/LOCAL LIFR IN SNOW AND LOW CIGS IS EXPECTED TONIGHT THROUGH
15Z SATURDAY...MAINLY NORTH OF INTERSTATE 80 TO THE SD BORDER.
MVFR/VFR CIGS ARE EXPECTED SATURDAY FROM 18Z ONWARD. THE MVFR IS
MOST LIKELY ALONG AND NORTH OF HIGHWAY 20.
MVFR/VFR CIGS ARE EXPECTED SATURDAY EVENING THROUGH 06Z.
CONFIDENCE IS GOOD AND THE RAP AND NAM MODELS WERE THE BASIS FOR
THE FORECAST.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL 6 PM CST /5 PM MST/ SATURDAY FOR
NEZ004>007-094.
WINTER WEATHER ADVISORY UNTIL 6 PM CST /5 PM MST/ SATURDAY FOR
NEZ008>010-022>029-035>038-056-057-059.
&&
$$
SHORT TERM...TAYLOR
LONG TERM...SPRINGER
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1010 PM SUN DEC 27 2015
.SYNOPSIS... A STRONG SUB-TROPICAL RIDGE OF HIGH PRESSURE WILL
PERSIST OFF THE SOUTHEAST COAST FOR THE NEXT FEW DAYS. A COLD FRONT
WILL DROP SOUTH THROUGH VIRGINIA TONIGHT AND INTO NORTH CAROLINA ON
MONDAY. A STRONG STORM SYSTEM WILL DEVELOP IN THE LOWER MISSISSIPPI
VALLEY ON MONDAY AND MOVE INTO THE EASTERN GREAT LAKES ON TUESDAY.
&&
.NEAR TERM /THROUGH MONDAY NIGHT/...
AS OF 1000 PM SUNDAY...
NO ADDITIONAL MAJOR CHANGES TO THE FORECAST TONIGHT. THE COLD FRONT
THAT WILL MOVE IN LATER TONIGHT IS CURRENTLY PUSHING THROUGH THE MID-
ATLANTIC STATES...WITH NORTHERLY WINDS APPROACHING CENTRAL VA. HIGH
CLOUDS ARE PLENTIFUL ACROSS THE CAROLINAS...WHICH MAY MAKE IT HARD
FOR FOG TO DEVELOP HERE IN CENTRAL NC...ESPECIALLY IN THE WESTERN
PIEDMONT. HOWEVER... THE HRRR STILL SHOWS A BRIEF PERIOD OF FOG OR
VERY LOW STRATUS IMMEDIATELY AHEAD OF THE FRONT AS WINDS
DIMINISH...MORE TOWARD 09-12Z. -22
PREVIOUS FORECAST... THE ANOMALOUS WARM SECTOR IN PLACE THIS PAST
WEEK WILL PERSIST OVER THE MAJORITY OF CENTRAL NC NIGHT...EXCEPT FOR
THE NORTHERN PIEDMONT AND NE COASTAL PLAIN LATER TONIGHT WHEN A BACK-
DOOR COLD FRONT PROGRESSES SOUTHWARD FROM VA INTO NC ~08-12Z. IN THE
NORTH...LOWS WILL PRIMARILY BE A FUNCTION OF COLD ADVECTION IN THE
WAKE OF THE COLD FRONTAL PASSAGE LATE TONIGHT (08-12Z MON)...PERHAPS
AIDED BY EVAPORATIVE COOLING ATTENDANT LIGHT RAIN AS SOUTH/SE LOW-
LEVEL FLOW (925-850 MB )ADVECTS A WARM/MOIST AIRMASS NORTHWARD ATOP
THE SHALLOW COLDER AIRMASS ADVECTING SOUTHWARD. IN THE SOUTH...LOW
TEMPS WILL BE DRIVEN BY RADIATIONAL COOLING (MAGNITUDE OF WHICH WILL
DEPEND ON CLOUD COVER). -VINCENT
AS THE FRONT DROPS SOUTH ON MONDAY...AREAS OF RAIN WILL LIKELY
EXPAND IN THE DEVELOPING OVER RUNNING PATTERN WHICH WILL LOCK IN
CLOUDS AND CONTRIBUTE ADDITIONAL COOLING. TEMPERATURES ACROSS THE
NORTHERN PIEDMONT AND NORTHERN COASTAL PLAIN WILL FALL INTO THE
UPPER 40S BY LATE IN THE DAY WITH THE COLD FRONT PUSHING THROUGH ALL
OF CENTRAL NC BY NIGHTFALL. THE COOLER AIR MASS WILL BE SLOWER TO
ARRIVE ACROSS THE SOUTHERN PIEDMONT AND SANDHILLS BY THE CLOUDS AND
PRECIPITATION WILL LIMIT THE DIURNAL TEMPERATURE RECOVERY.
NWP GUIDANCE GUIDANCE HAS BEEN CONSISTENT IN QUICKLY SCOURING THE
LOW LEVEL COLD AIR MASS ON MONDAY NIGHT WITH THE WARM FRONT PUSHING
NORTH INTO THE DC AREA BY DAYBREAK TUESDAY. PAST EXPERIENCE SUGGESTS
THAT THIS IS LIKELY TOO FAST AND HAVE SLOWED THE PASSAGE OF THE WARM
FRONT BY 2-4 HOURS WHICH STILL MAY NOT BE SUFFICIENT IF THE HYBRID
CAD EVENT LOCKS IN. STILL IT WILL BE A CLOUDY AND DAMP NIGHT WITH
PERIODS OF RAIN AND TEMPERATURES STEADY AND THEN BEGINNING TO RISE
TOWARD DAYBREAK. -BLAES
&&
.SHORT TERM /TUESDAY AND TUESDAY NIGHT/...
AS OF 230 PM SUNDAY...
MODELS HAVE CONSISTENTLY FORECAST THE CAD TO SCOUR RAPIDLY LATE
MONDAY NIGHT AHEAD OF AN APPROACHING WEAK COLD FRONT. ANY LINGERING
LIGHT RAIN MONDAY NIGHT WILL TAPER TO SCATTERED SHOWERS EARLY
TUESDAY AS LOW LEVEL FLOW VEERS AROUND TO SOUTH AND SOUTHWEST...
ENDING THE ISENTROPIC LIFT AND INITIATING STRONG WARM AIR ADVECTION.
WOULD EXPECT DENSER CLOUD COVERAGE AND POSSIBLY SOME LINGERING LIGHT
RAIN TO DELAY THE ONSET OF THE WARMUP A BIT IN THE WESTERN
PIEDMONT...WHICH SHOULD STILL REACH THE MID 60S...WITH LOW TO
MID 70S ELSEWHERE...AND POSSIBLY SOME UPPER 70S SOUTHEAST.
THE FRONTAL ZONE WILL BE SOUTH AND EAST OF THE AREA BY LATE TUESDAY.
THE RELATIVE LULL IN PRECIP CHANCES WILL BE SHORT-LIVED...HOWEVER...
AS A SURFACE LOW DEVELOPING IN THE NORTHCENTRAL GULF LIFTS NORTH
INTO THE TENNESSEE VALLEY AND PULLS THE FRONTAL ZONE BACK TO THE
WEST...WHICH WILL MAINTAIN THE MILD AIRMASS OVER THE REGION WITH
MINS MOSTLY IN THE MID AND UPPER 50S.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 230 PM SUNDAY...
A POTENT SHORT WAVE MOVING ACROSS THE GREAT LAKES REGION WILL PUSH
THE SUBTROPICAL RIDGE OVER THE EASTERN CONUS FURTHER OFFSHORE.
THE ENSUING DEEP SOUTHWEST FLOW WILL BE NEAR-PARALLEL TO THE SURFACE
FRONTAL ZONE OVER THE AREA...SO IT WILL LINGER ACROSS THE AREA WITH
PERIODS OF FAIRLY WIDESPREAD SHOWER COVERAGE FROM WEDNESDAY THROUGH
THURSDAY. WILL HAVE LIKELY POPS ACROSS THE ENTIRE AREA WED AND WED
NIGHT...SHIFTING TO THE EAST ON THURSDAY WHEN THE FRONT IS FINALLY
PUSHED OFFSHORE BY A STRONGER UPPER TROF ROTATING ACROSS THE
MIDWEST. HIGHS BOTH WED AND THU WILL BE IN THE 60S AFTER MORNING
LOWS IN THE 50S.
HIGH PRESSURE WILL BE BUILDING IN AS THE FRONT MOVES OFFSHORE
THURSDAY NIGHT AND A COOLER AIRMASS WILL SETTLE INTO THE AREA. THE
TRANSITION TO EAST COAST TROFFING WILL BE A RELATIVELY SLOW
PROCESS...WITH ENSUING SHORT WAVES PROGRESSIVELY DEEPENING THE TROF
AS THEY DIG INTO THE UPPER MIDWEST/OHIO VALLEY ON FRIDAY AND
SATURDAY. INITIAL SEASONABLY MILD HIGH TEMPERATURES IN THE 50S
FRIDAY WILL FALL INTO THE MID TO UPPER 40S FOR THE WEEKEND AS THE
PROGRESSIVE SHORT WAVES DEEPEN THE UPPER TROF AND PROVIDE US WITH
REINFORCING WAVES OF COOLER DRY AIR. RADIATIONAL CONDITIONS WILL BE
MORE FAVORABLE IN THE DRY AIRMASS AND WEAKER FLOW AS THE SURFACE
HIGH BUILDS IN...RESULTING IN MINS FALLING INTO THE 30S SATURDAY
MORNING...WITH MOST AREAS AT OR BELOW FREEZING SUNDAY MORNING.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
AS OF 655 PM SUNDAY...
AVIATION CONDITIONS WILL BE DETERIORATING RAPIDLY LATE TONIGHT AS A
COLD FRONT CURRENTLY MOVING THROUGH THE CENTRAL APPALACHIANS WILL
BEND SOUTH THIS EVENING AND SURGE THROUGH VA AND NC EARLY MONDAY
MORNING. AHEAD OF THE FRONT...A LIGHT SOUTHWEST WIND SHOULD BRIEFLY
GO CALM...WHICH MAY ALLOW SOME FOG TO DEVELOP AFTER 06Z...MAINLY
SOUTH OF KRDU TO KRWI. THE COLD FRONT...PROGGED TO BE NEAR KRIC
AROUND 06Z...WILL CAUSE CEILINGS TO LOWER FROM MVFR TO AT LEAST IFR
BY 09-12Z. A PERIOD OF LIFR CEILINGS IS POSSIBLE AS WELL..THOUGH A
STRENGTHENING 10-12KT NORTHEAST WIND (GUSTING TO AROUND 20KT) SHOULD
CAUSE CEILINGS AND VSBYS TO RISE A LITTLE...WITH IFR CEILINGS FROM
KINT TO KRWI AND MVFR A LITTLE MORE LIKELY AT KFAY. PERIODS OF
MOSTLY LIGHT RAIN AND DRIZZLE MAY ALSO DROP VSBYS AT TIMES.
LOOKING FURTHER AHEAD... ANOTHER STORM SYSTEM WILL BRING A RETURN OF
ADVERSE AVIATION CONDITIONS WITH MVFR/IFR CONDITIONS MONDAY AND
EARLY TUESDAY. SOME SLIGHT IMPROVEMENT MAY OCCUR TUESDAY NIGHT
BEFORE ANOTHER STORM SYSTEM BRINGS ADDITIONAL ADVERSE AVIATION
CONDITIONS ON WEDNESDAY AND INTO THURSDAY. IMPROVEMENT IS EXPECT
BY FRIDAY.
&&
.CLIMATE...
HERE ARE THE AREA RECORD MAXIMUMS AND HIGH MINIMUMS FOR DECEMBER
27TH. RECORDS HAVE BEEN KEPT IN THE GREENSBORO AREA SINCE
1903... IN THE RALEIGH AREA SINCE 1887... AND IN THE FAYETTEVILLE
AREA SINCE 1910.
DEC 27: RECORD MAXIMUM HIGH MINIMUM
GREENSBORO 71 (1971) 52 (1940)
RALEIGH 73 (1904) 58 (1949)
FAYETTEVILLE 74 (1987) 61 (1973)
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BLAES
NEAR TERM...22/VINCENT/BLAES
SHORT TERM...MLM
LONG TERM...MLM
AVIATION...22
CLIMATE...RAH
AREA FORECAST DISCUSSION
NWS NORMAN OK
752 PM CST SUN DEC 27 2015
.UPDATE...
NO CHANGES TO CURRENT HEADLINES/FORECAST AT THIS TIME. CONCERNS
THIS EVENING INCLUDE PROSPECTS FOR INCREASING POWER OUTAGES AND
DANGEROUS TRAVEL CONDITIONS ACROSS THE REGION THROUGH MONDAY
MORNING.
THE ONGOING WINTER STORM APPEARS TO BE EVOLVING MUCH AS EXPECTED.
WATER VAPOR/RADAR SHOWS AN EXTENSIVE PRECIP SHIELD NOW EXITING
OKLAHOMA TO THE EAST. FREEZING DRIZZLE WITH INTERMITTENT LIGHT
SNOW IS FALLING IN THE RELATIVELY LIGHT RADAR ECHOES SEEN OVER
MUCH OF WESTERN/CENTRAL OKLAHOMA. FOCUS NOW SHIFTS TO THE NEXT
BOUT OF DEEP FORCING/ASCENT EVIDENT IN VAPOR/RADAR IMAGERY
EMERGING FROM WESTERN NORTH TEXAS.
THIS RENEWED ROUND OF PRECIPITATION IS WELL HANDLED BY SEVERAL OF
THE HIGH RESOLUTION MODELS. THE HRRR AND TTU WRF SOLUTIONS DEPICT
MODERATE TO HEAVY PRECIP OVERSPREADING WESTERN OKLAHOMA IN THE
NEXT 1 TO 3 HOURS...THEN CENTRAL OKLAHOMA BY 05-07Z. PRECIP TYPES
RANGE FROM ALL SNOW IN NORTHWEST OKLAHOMA...TO A WINTRY MIX
ELSEWHERE...WITH INDICATIONS THAT SLEET MAY BE MORE DOMINANT IN
SOUTHWEST AND CENTRAL OKLAHOMA WHERE 1 TO 2 INCH SLEET
ACCUMULATIONS MAY OCCUR. PROFILES SUPPORT A TRANSITION TO
LIGHT/WIND BLOWN SNOW BY MID MORNING MONDAY. WIND SPEEDS APPEAR
TO REMAIN IN THE 20 TO 30 MPH RANGE THROUGH AT LEAST 18Z
MONDAY...WHICH WILL EXACERBATE ONGOING ISSUES WITH DAMAGED
UTILITIES/POWER OUTAGES. WINTRY PRECIPITATION SHOULD BEGIN TO
WANE DURING THE MIDDAY/EARLY AFTERNOON HOURS MONDAY...WITH SOME
WRAP AROUND SNOW LINGERING OVER NORTH/CENTRAL OKLAHOMA BEFORE
ENDING.
&&
.PREV DISCUSSION... /ISSUED 622 PM CST SUN DEC 27 2015/
DISCUSSION...
AVIATION...
IFR CONDITIONS ARE EXPECTED THROUGH THE FIRST HALF OF MONDAY.
BLIZZARD CONDITIONS WILL OCCUR IN WESTERN OKLAHOMA WITH FREEZING
RAIN...SLEET...THEN SNOW OVER MUCH OF THE WESTERN HALF OF THE
STATE. VERY STRONG NORTH WINDS WILL GUST OVER 40 MPH THROUGH
MONDAY MORNING BEFORE SUBSIDING IN THE AFTERNOON.
PREV DISCUSSION... /ISSUED 345 PM CST SUN DEC 27 2015/
DISCUSSION...
PRECIPITATION CONTINUES TO SLOWLY MOVE NORTHWARD OVER PORTIONS OF
WEST TEXAS AND THE SOUTHERN TX PANHANDLE THIS AFTERNOON...AS THE
MID TO UPPER LOW SWINGS ENE. THE LOW WILL BEGIN TO LIFT TO THE
NORTH LATE TONIGHT OVER NORTH TEXAS. TWO LOCATIONS OF
PRECIPITATION WILL ACCOMPANY IT. THE FIRST WILL BE MOSTLY SNOW
MOVING INTO WESTERN NORTH TEXAS...SOUTHWESTERN OK...AND WESTERN OK
THIS EVENING...AND EVENTUALLY INTO NORTHERN AND NORTHWESTERN OK
EARLY TOMORROW MORNING. THE OTHER WILL BE LOCATED OVER CENTRAL OK
WHERE SLEET...SNOW...AND SOME FREEZING RAIN WILL OCCUR. THE ICE
STORM WARNING HAS BEEN CANCELLED AND REPLACED WITH A WINTER STORM
AND BLIZZARD WARNINGS. THE DEPTH OF THE COLD AIR IS TOO DEEP FOR
FZRA. THE HEAVIEST SNOW WILL IMPACT W/SW OK LATE TONIGHT RESULTING
IN NEAR 0 VISBY. IT`S A BIT UNCLEAR HOW FAR NORTH THE HEAVIEST
SNOW WILL MAKE IT, BUT DECIDED TO KEEP BLIZZARD WARNING IN EFFECT
FOR NW OK FOR NOW. THIS MAY BE DOWNGRADED AT A LATER TIME.
SOME ICE ACCUMULATION IS STILL EXPECTED THROUGH EARLY
TOMORROW MORNING, ESPECIALLY ACROSS CENTRAL/SOUTH CENTRAL OK WHERE
WARMER NOSE AT 700 MB WILL NUDGE IN AROUND THE LOW. HOWEVER, IT
SHOULD BE BRIEF AND TOTALS SHOULD REMAIN BELOW WARNING CRITERIA.
REGARDLESS, WIND SPEEDS WILL ONLY SLOWLY DECREASE THROUGH EARLY
TOMORROW AND POWER OUTAGES ARE STILL A CONCERN. SLEET ACCUMULATION
LATE TONIGHT THROUGH TOMORROW WILL LIKELY BE HIGHEST ACROSS
CENTRAL OK WHERE SUFFICIENT MOISTURE AND LIFT THROUGH THE
DENDRITIC ZONE WILL RESIDE...BEFORE A TRANSITION TO SNOW OCCURS
JUST BEFORE SUNRISE. THE LOW WILL QUICKLY EXIT OUR REGION TO THE
NE BY 18Z TOMORROW, BUT TRAIL SOME PATCHY SNOW/BLOWING SNOW
ACROSS CENTRAL AND NORTHERN OK PERHAPS THROUGH LUNCHTIME.
AT LEAST A 24 HOUR BREAK IN THE PRECIPITATION IS EXPECTED TUE
BEFORE A SHORTWAVE TROUGH MOVES OUT OF THE SOUTHERN ROCKIES TUES
NIGHT. THE TREND WITH THIS WAVE HAS BEEN TO DIG A BIT SOUTH AND
SLIGHTLY DEEPER. BASED ON THIS, AND MOISTURE PROFILES ACROSS
NORTHERN OK, DECIDED TO BUMP POPS INTO THE HIGH CHC CAT TUE NIGHT.
HOWEVER, IT WILL BE PROGRESSIVE SO SNOW AMOUNTS SHOULD REMAIN
AROUND 1 IN. AFTER WED AM, PRECIP CHANCES WILL END FOR THE WEEK
BUT BELOW AVG TEMPS WILL PERSIST.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 28 32 18 36 / 90 80 0 0
HOBART OK 24 31 15 33 / 90 20 0 0
WICHITA FALLS TX 28 36 19 41 / 100 20 0 10
GAGE OK 21 27 7 28 / 80 30 0 20
PONCA CITY OK 27 31 14 32 / 100 80 10 0
DURANT OK 36 39 27 46 / 90 50 0 0
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...WINTER STORM WARNING UNTIL 6 PM CST MONDAY FOR OKZ006>008-
011>013-015>019-022>025-027>029-034>038.
BLIZZARD WARNING UNTIL 6 PM CST MONDAY FOR OKZ004-005-009-010-
014-021-033.
WINTER WEATHER ADVISORY UNTIL 6 PM CST MONDAY FOR OKZ020-026-030-
039-040-044-045.
FLASH FLOOD WATCH UNTIL 6 AM CST MONDAY FOR OKZ026-028>032-
039>043-045>048-050>052.
TX...WINTER STORM WARNING UNTIL 6 PM CST MONDAY FOR TXZ084-085-087.
BLIZZARD WARNING UNTIL 6 PM CST MONDAY FOR TXZ083.
WINTER WEATHER ADVISORY UNTIL 6 PM CST MONDAY FOR TXZ086-088>090.
&&
$$
20
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
449 PM EST SAT DEC 26 2015
.SYNOPSIS...
A WARM FRONT WILL MOVE SLOWLY NORTHWARD THROUGH THE REGION
OVERNIGHT. SUNDAY LOOKS ANOTHER RECORD SETTING WARM DAY BEFORE
COLDER AIR MAKES A RETURN SUNDAY NIGHT INTO MONDAY.
A STORM DURING THE FIRST PART OF THE WORK WEEK COULD START OUT AS
A LIGHT WINTRY MIX OVER NORTHERN AREAS BEFORE CHANGING TO BACK TO
JUST RAIN BEFORE ENDING. TEMPERATURES WILL COOL OFF TO NEAR NORMAL
THROUGH THE REST OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
THE RADAR CONTINUES TO SHOW A DISORGANIZED AREA OF MAINLY LIGHT
RAIN FROM THE CENTRAL MOUNTAINS NORTH AND EAST. THE HRRR SHOWS
THIS DISORGANIZED ACTIVITY MORE OR LESS CONTINUING THROUGHOUT THE
DAY...STILL FAVORING THESE NORTHERN AREAS...BEFORE A STEADIER AND
MORE WIDESPREAD SHIELD OF RAIN SPREADS INTO THE REGION AFTER DARK.
THE WARM FRONT TO OUR SOUTH WILL PROGRESS NORTHWARD OVERNIGHT.
ON FIRST GLANCE THE SURFACE PRESSURE TROUGH LOOKS LIKE IT SHOULD
PASS TO OUR NORTH BY MIDNIGHT OR SO...BUT A CLOSER LOOKS SHOWS A
FAIRLY SUBSTANTIAL COLD AIR DAMMING SIGNATURE THAT WILL SLOW THE
WARMUP. THE NAM/GFS BOTH SHOW A VIGOROUS NORTHEASTERLY COMPONENT
TO THE LOW LEVEL AGEOSTROPHIC FLOW AND THE SURFACE BASED LIFTED
INDICES SHOW THE CLASSIC STABLE WEDGE HOLDING THROUGH 12Z BEFORE
MIXING OUT JUST AHEAD OF THE FRONT AS IT RE-ENTERS THE REGION AS
A COLD FRONT FROM THE WEST.
I DID KEEP THE MENTION OF A SMALL CHANCE OF A RUMBLE OF THUNDER
OVER NWRN AREAS LATER TONIGHT AS THAT`S WHERE THE STABILITY ERODES
MOST SIGNIFICANTLY. LI`S ARE FORECAST TO APPROACH ZERO AND MID
LEVEL LAPSE RATES EXCEED 6C/KM.
THE SLOW PROGRESS OF THE WARM AIR ARGUES FOR NEAR STEADY/SLOWLY
RISING TEMPS FOR THE LATTER HALF OF THE NIGHT. OVERALL STILL MUCH
MILDER THAN NORMAL FOR LATE DECEMBER.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH 6 PM SUNDAY/...
THE COLD FRONT WILL BE ENTERING MY WESTERN ZONES EARLY IN THE
DAY...BUT PROBABLY WILL NOT BE FAST ENOUGH TO PREVENT HIGH TEMPS
FROM SOARING INTO THE 60S OR EVEN LOWER 70S OVER MUCH OF THE
SOUTHERN 2/3 OR SO OF THE REGION. SHORT RANGE GUIDANCE AGREES THAT
THE FRONT WILL CLEAR MY SERN ZONES BY NIGHTFALL BEFORE BECOMING
STATIONARY YET AGAIN JUST SOUTH OF THE STATE.
THE BEST CHANCE FOR RAIN WILL BE OVER THE NORTHERN 1/2 OF THE CWA
AS THE FRONT SAGS SOUTH...WITH SHOWERS BEING MORE SPOTTY OVER
SOUTHERN LOCATIONS.
RECORD HIGHS FOR THE 27TH...
52F AT IPT AND 59F AT MDT.
&&
.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
VERY MOIST STREAM OF AIR WILL BE AIMED AT PA...VIA SOUTHWESTERLY
FLOW...THROUGH MUCH OF THE LONG TERM PERIOD. UPPER RIDGE ALONG
THE EAST COAST WILL BE PUSHED EAST BY NRN STREAM SHORTWAVE
ENERGY...AND THE SLOW EASTWARD PROGRESSION OF LARGER SCALE TROF
NOW OVER THE SWRN U.S...AIDED ALSO BY SHORTWAVE WITHIN.
MON-DAY WILL BE QUITE CHILLY - BUT VERY NEARLY NORMAL - AS TEMPS
GO LITTLE UPWARD THROUGH THE DAY. NORTH WINDS WILL BRING IN SOME
DECENTLY COLD AIR FROM A LARGE HIGH PRESSURE AREA MOVING ACROSS
CANADA AND INTO NEW ENGLAND. THE COLD AIR IS THE MOST INTERESTING
CHALLENGE IN THIS FORECAST...AND MAYBE FOR THE NEXT WEEK-PLUS. HOW
DEEP THE COLD AIR CAN GET AND HOW PERSISTENT IT WILL BE AGAINST
THE WARM AIR ADVECTION FROM A VERY STRONG LOW PRESSURE AREA MOVING
UP FROM THE LOWER MS VALLEY. SE WINDS OF 40KTS AT 8H MONDAY WILL
INCREASE TO 60KTS AS THEY VEER TO COME FROM DUE SOUTH. THE
MOISTURE TRANSPORT RESULTS IN PWATS OF 3 STANDARD DEVIATIONS ABOVE
NORMAL...WHICH IS NOT MUCH COMPARED TO SUNDAY/S LOFTY VALUES.
HOWEVER...THE MOISTURE ROLLING OVERHEAD WILL LIKELY BE LIQUID
FALLING INTO THE SUB- FREEZING AIR IN THE LOWEST 2-4KFT.
THE TROUBLE WOULD BE RE-FROZEN/FREEZING PRECIP LATE IN THE DAY ON
MONDAY AND MONDAY NIGHT. THE COLDEST/DEEPEST COLD AIR WILL BE IN
THE NERN MTNS AND MAY GET TRAPPED IN CENTRAL PA. HOWEVER...THE
TEMP GUIDANCE AT THIS POINT IS SOLID WITH CONTINUITY AND KEEPS THE
SRN HALF OF THE AREA ABOVE FREEZING THROUGH THE PERIOD. THE RECORD
WARMTH OF RECENT TIMES AND WARM/WET GROUND WILL BE NEGATIVES TO
FREEZING RAIN. SREF MEMBER P-TYPES PAINT A HIGH LIKELIHOOD OF
SLEET VS. FZRA. IN THE PAST...FORECASTS OF IP HAVE BEEN OVERDONE
BY THE SREFS AND A GREAT UNCERTAINTY REMAINS AS TO WHAT THE P-TYPE
WILL BE AND HOW LONG IT COULD STAY SOMETHING OTHER THAN PLAIN
RAIN. WILL KEEP IT CLOSE TO THE GOING FCST...BUT MENTION LESS
FZRA. BY TUESDAY MORNING....THE TEMP PROFILES ARE ENTIRELY RAIN
SAVE FOR PERHAPS TIOGA CO. THE PRECIP DOES PASS THROUGH IN
12-15HRS. THE STORM DEVELOPS A SECONDARY LOW OVER MD/DE AND SHOULD
CUT THINGS OFF TUESDAY MORNING. HELD SOME CHC POPS THRU THE AFTN
TO ACCOUNT FOR TIMING UNCERTAINTY.
ANOTHER UPPER SHORT WAVE IS IN STORE FOR EARLY THU AND BRINGS
RAIN...THEN COLDER AIR FOR THE LATER PART OF THE WEEK. TEMPS
FINALLY GET COLD ENOUGH AND FLOW OUT OF THE W/NW TO GENERATE LOTS
OF LAKE EFFECT SNOW. LAKES TEMPS HAVE GOT TO BE MUCH ABOVE
NORMAL...WHICH SHOULD HELP GENERATE PLENTY OF INSTABILITY AND
MOISTURE FLUX. 8H TEMPS DROP INTO THE NEGATIVE DOUBLE-DIGITS FRI-
MON UNDER A VERY DEEP UPPER TROUGH.
&&
.AVIATION /22Z SATURDAY THROUGH THURSDAY/...
AS EXPECTED...NOT A LOT OF RAIN OR FOG SO FAR. ONLY A FEW
SPRINKLES. WHILE CIGS ARE LOW...FOG AND HZ NOT WIDESPREAD.
A FAST MOVING BAND OF RAIN TO THE SW WILL QUICKLY LIFT NE
ACROSS THE REGION THIS EVENING.
MINOR ADJUSTMENTS MADE TO 21Z TAFS.
EARLIER DISCUSSION BELOW.
CONDITIONS WILL DETERIORATE FROM SW TO NE AS A SLOWLY ADVANCING
WARM FRONT APPROACHES FROM THE SOUTH. EASTERN TERMINALS WILL
REMAIN VFR INTO THE LATE AFTERNOON BEFORE CONDITIONS DROP THERE
AS WELL.
EXPECT WIDESPREAD IFR/MVFR OVERNIGHT ALONG WITH AREAS OF RAIN.
THERE COULD BE A THUNDERSTORM OVER NWRN AREAS AHEAD OF A COLD
FRONT THAT WILL ENTER THE AREA SUNDAY MORNING.
OUTLOOK...
SUN...IFR/MVFR WITH PERIODS OF RAIN. IMPROVING CONDITIONS...ESPECIALLY
OVER SOUTHERN TERMINALS.
MON...VFR EARLY WITH AREAS MVFR AND RAIN DEVELOPING FROM WEST TO
EAST IN THE AFTERNOON.
MON NIGHT...DETERIORATING CONDITIONS. RAIN DEVELOPING /POSSIBLY A
WINTRY MIX NORTH/.
TUE...RAIN SHOWERS TAPERING OFF. GENERALLY MVFR WITH SLOWLY
IMPROVING CONDITIONS.
WED-THU...MVFR LIKELY NW. VFR SE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...LA CORTE
SHORT TERM...LA CORTE
LONG TERM...DANGELO/GARTNER
AVIATION...LA CORTE/MARTIN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
353 PM EST SAT DEC 26 2015
.SYNOPSIS...
A WARM FRONT WILL MOVE SLOWLY NORTHWARD THROUGH THE REGION
OVERNIGHT. SUNDAY LOOKS ANOTHER RECORD SETTING WARM DAY BEFORE
COLDER AIR MAKES A RETURN SUNDAY NIGHT INTO MONDAY.
A STORM DURING THE FIRST PART OF THE WORK WEEK COULD START OUT AS
A LIGHT WINTRY MIX OVER NORTHERN AREAS BEFORE CHANGING TO BACK TO
JUST RAIN BEFORE ENDING. TEMPERATURES WILL COOL OFF TO NEAR NORMAL
THROUGH THE REST OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
THE RADAR CONTINUES TO SHOW A DISORGANIZED AREA OF MAINLY LIGHT
RAIN FROM THE CENTRAL MOUNTAINS NORTH AND EAST. THE HRRR SHOWS
THIS DISORGANIZED ACTIVITY MORE OR LESS CONTINUING THROUGHOUT THE
DAY...STILL FAVORING THESE NORTHERN AREAS...BEFORE A STEADIER AND
MORE WIDESPREAD SHIELD OF RAIN SPREADS INTO THE REGION AFTER DARK.
THE WARM FRONT TO OUR SOUTH WILL PROGRESS NORTHWARD OVERNIGHT. ON
FIRST GLANCE THE SURFACE PRESSURE TROUGH LOOKS LIKE IT SHOULD
PASS TO OUR NORTH BY MIDNIGHT OR SO...BUT A CLOSER LOOKS SHOWS A
FAIRLY SUBSTANTIAL COLD AIR DAMMING SIGNATURE THAT WILL SLOW THE
WARMUP. THE NAM/GFS BOTH SHOW A VIGOROUS NORTHEASTERLY COMPONENT
TO THE LOW LEVEL AGEOSTROPHIC FLOW AND THE SURFACE BASED LIFTED
INDICES SHOW THE CLASSIC STABLE WEDGE HOLDING THROUGH 12Z BEFORE
MIXING OUT JUST AHEAD OF THE FRONT AS IT RE-ENTERS THE REGION AS A
COLD FRONT FROM THE WEST.
I DID KEEP THE MENTION OF A SMALL CHANCE OF A RUMBLE OF THUNDER
OVER NWRN AREAS LATER TONIGHT AS THAT`S WHERE THE STABILITY ERODES
MOST SIGNIFICANTLY. LI`S ARE FORECAST TO APPROACH ZERO AND MID
LEVEL LAPSE RATES EXCEED 6C/KM.
THE SLOW PROGRESS OF THE WARM AIR ARGUES FOR NEAR STEADY/SLOWLY
RISING TEMPS FOR THE LATTER HALF OF THE NIGHT. OVERALL STILL MUCH
MILDER THAN NORMAL FOR LATE DECEMBER.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH 6 PM SUNDAY/...
THE COLD FRONT WILL BE ENTERING MY WESTERN ZONES EARLY IN THE
DAY...BUT PROBABLY WILL NOT BE FAST ENOUGH TO PREVENT HIGH TEMPS
FROM SOARING INTO THE 60S OR EVEN LOWER 70S OVER MUCH OF THE
SOUTHERN 2/3 OR SO OF THE REGION. SHORT RANGE GUIDANCE AGREES THAT
THE FRONT WILL CLEAR MY SERN ZONES BY NIGHTFALL BEFORE BECOMING
STATIONARY YET AGAIN JUST SOUTH OF THE STATE.
THE BEST CHANCE FOR RAIN WILL BE OVER THE NORTHERN 1/2 OF THE CWA
AS THE FRONT SAGS SOUTH...WITH SHOWERS BEING MORE SPOTTY OVER
SOUTHERN LOCATIONS.
RECORD HIGHS FOR THE 27TH...
52F AT IPT AND 59F AT MDT.
&&
.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
VERY MOIST STREAM OF AIR WILL BE AIMED AT PA...VIA SOUTHWESTERLY
FLOW...THROUGH MUCH OF THE LONG TERM PERIOD. UPPER RIDGE ALONG
THE EAST COAST WILL BE PUSHED EAST BY NRN STREAM SHORTWAVE
ENERGY...AND THE SLOW EASTWARD PROGRESSION OF LARGER SCALE TROF
NOW OVER THE SWRN U.S...AIDED ALSO BY SHORTWAVE WITHIN.
MON-DAY WILL BE QUITE CHILLY - BUT VERY NEARLY NORMAL - AS TEMPS
GO LITTLE UPWARD THROUGH THE DAY. NORTH WINDS WILL BRING IN SOME
DECENTLY COLD AIR FROM A LARGE HIGH PRESSURE AREA MOVING ACROSS
CANADA AND INTO NEW ENGLAND. THE COLD AIR IS THE MOST INTERESTING
CHALLENGE IN THIS FORECAST...AND MAYBE FOR THE NEXT WEEK-PLUS. HOW
DEEP THE COLD AIR CAN GET AND HOW PERSISTENT IT WILL BE AGAINST
THE WARM AIR ADVECTION FROM A VERY STRONG LOW PRESSURE AREA MOVING
UP FROM THE LOWER MS VALLEY. SE WINDS OF 40KTS AT 8H MONDAY WILL
INCREASE TO 60KTS AS THEY VEER TO COME FROM DUE SOUTH. THE
MOISTURE TRANSPORT RESULTS IN PWATS OF 3 STANDARD DEVIATIONS ABOVE
NORMAL...WHICH IS NOT MUCH COMPARED TO SUNDAY/S LOFTY VALUES.
HOWEVER...THE MOISTURE ROLLING OVERHEAD WILL LIKELY BE LIQUID
FALLING INTO THE SUB- FREEZING AIR IN THE LOWEST 2-4KFT.
THE TROUBLE WOULD BE RE-FROZEN/FREEZING PRECIP LATE IN THE DAY ON
MONDAY AND MONDAY NIGHT. THE COLDEST/DEEPEST COLD AIR WILL BE IN
THE NERN MTNS AND MAY GET TRAPPED IN CENTRAL PA. HOWEVER...THE
TEMP GUIDANCE AT THIS POINT IS SOLID WITH CONTINUITY AND KEEPS THE
SRN HALF OF THE AREA ABOVE FREEZING THROUGH THE PERIOD. THE RECORD
WARMTH OF RECENT TIMES AND WARM/WET GROUND WILL BE NEGATIVES TO
FREEZING RAIN. SREF MEMBER P-TYPES PAINT A HIGH LIKELIHOOD OF
SLEET VS. FZRA. IN THE PAST...FORECASTS OF IP HAVE BEEN OVERDONE
BY THE SREFS AND A GREAT UNCERTAINTY REMAINS AS TO WHAT THE P-TYPE
WILL BE AND HOW LONG IT COULD STAY SOMETHING OTHER THAN PLAIN
RAIN. WILL KEEP IT CLOSE TO THE GOING FCST...BUT MENTION LESS
FZRA. BY TUESDAY MORNING....THE TEMP PROFILES ARE ENTIRELY RAIN
SAVE FOR PERHAPS TIOGA CO. THE PRECIP DOES PASS THROUGH IN
12-15HRS. THE STORM DEVELOPS A SECONDARY LOW OVER MD/DE AND SHOULD
CUT THINGS OFF TUESDAY MORNING. HELD SOME CHC POPS THRU THE AFTN
TO ACCOUNT FOR TIMING UNCERTAINTY.
ANOTHER UPPER SHORT WAVE IS IN STORE FOR EARLY THU AND BRINGS
RAIN...THEN COLDER AIR FOR THE LATER PART OF THE WEEK. TEMPS
FINALLY GET COLD ENOUGH AND FLOW OUT OF THE W/NW TO GENERATE LOTS
OF LAKE EFFECT SNOW. LAKES TEMPS HAVE GOT TO BE MUCH ABOVE
NORMAL...WHICH SHOULD HELP GENERATE PLENTY OF INSTABILITY AND
MOISTURE FLUX. 8H TEMPS DROP INTO THE NEGATIVE DOUBLE-DIGITS FRI-
MON UNDER A VERY DEEP UPPER TROUGH.
&&
.AVIATION /21Z SATURDAY THROUGH THURSDAY/...
CONDITIONS WILL DETERIORATE FROM SW TO NE AS A SLOWLY ADVANCING
WARM FRONT APPROACHES FROM THE SOUTH. EASTERN TERMINALS WILL
REMAIN VFR INTO THE LATE AFTERNOON BEFORE CONDITIONS DROP THERE
AS WELL.
EXPECT WIDESPREAD IFR/MVFR OVERNIGHT ALONG WITH AREAS OF RAIN.
THERE COULD BE A THUNDERSTORM OVER NWRN AREAS AHEAD OF A COLD
FRONT THAT WILL ENTER THE AREA SUNDAY MORNING.
OUTLOOK...
SUN...IFR/MVFR WITH PERIODS OF RAIN. IMPROVING CONDITIONS...ESPECIALLY
OVER SOUTHERN TERMINALS.
MON...VFR EARLY WITH AREAS MVFR AND RAIN DEVELOPING FROM WEST TO
EAST IN THE AFTERNOON.
MON NIGHT...DETERIORATING CONDITIONS. RAIN DEVELOPING /POSSIBLY A
WINTRY MIX NORTH/.
TUE...RAIN SHOWERS TAPERING OFF. GENERALLY MVFR WITH SLOWLY
IMPROVING CONDITIONS.
WED-THU...MVFR LIKELY NW. VFR SE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...LA CORTE
SHORT TERM...LA CORTE
LONG TERM...DANGELO/GARTNER
AVIATION...LA CORTE
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
239 PM EST SAT DEC 26 2015
.SYNOPSIS...
A WARM FRONT WILL MOVE SLOWLY NORTHWARD THROUGH THE REGION
OVERNIGHT. SUNDAY LOOKS ANOTHER RECORD SETTING WARM DAY BEFORE
COLDER AIR MAKES A RETURN SUNDAY NIGHT INTO MONDAY.
A STORM DURING THE FIRST PART OF THE WORK WEEK COULD START OUT AS
A LIGHT WINTRY MIX OVER NORTHERN AREAS BEFORE CHANGING TO BACK TO
JUST RAIN BEFORE ENDING. TEMPERATURES WILL COOL OFF TO NEAR NORMAL
THROUGH THE REST OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
THE RADAR CONTINUES TO SHOW A DISORGANIZED AREA OF MAINLY LIGHT
RAIN FROM THE CENTRAL MOUNTAINS NORTH AND EAST. THE HRRR SHOWS
THIS DISORGANIZED ACTIVITY MORE OR LESS CONTINUING THROUGHOUT THE
DAY...STILL FAVORING THESE NORTHERN AREAS...BEFORE A STEADIER AND
MORE WIDESPREAD SHIELD OF RAIN SPREADS INTO THE REGION AFTER DARK.
THE WARM FRONT TO OUR SOUTH WILL PROGRESS NORTHWARD OVERNIGHT. ON
FIRST GLANCE THE SURFACE PRESSURE TROUGH LOOKS LIKE IT SHOULD
PASS TO OUR NORTH BY MIDNIGHT OR SO...BUT A CLOSER LOOKS SHOWS A
FAIRLY SUBSTANTIAL COLD AIR DAMMING SIGNATURE THAT WILL SLOW THE
WARMUP. THE NAM/GFS BOTH SHOW A VIGOROUS NORTHEASTERLY COMPONENT
TO THE LOW LEVEL AGEOSTROPHIC FLOW AND THE SURFACE BASED LIFTED
INDICES SHOW THE CLASSIC STABLE WEDGE HOLDING THROUGH 12Z BEFORE
MIXING OUT JUST AHEAD OF THE FRONT AS IT RE-ENTERS THE REGION AS A
COLD FRONT FROM THE WEST.
I DID KEEP THE MENTION OF A SMALL CHANCE OF A RUMBLE OF THUNDER
OVER NWRN AREAS LATER TONIGHT AS THAT`S WHERE THE STABILITY ERODES
MOST SIGNIFICANTLY. LI`S ARE FORECAST TO APPROACH ZERO AND MID
LEVEL LAPSE RATES EXCEED 6C/KM.
THE SLOW PROGRESS OF THE WARM AIR ARGUES FOR NEAR STEADY/SLOWLY
RISING TEMPS FOR THE LATTER HALF OF THE NIGHT. OVERALL STILL MUCH
MILDER THAN NORMAL FOR LATE DECEMBER.
&&
.SHORT TERM /SUNDAY/...
THE COLD FRONT WILL BE ENTERING MY WESTERN ZONES EARLY IN THE
DAY...BUT PROBABLY WILL NOT BE FAST ENOUGH TO PREVENT HIGH TEMPS
FROM SOARING INTO THE 60S OR EVEN LOWER 70S OVER MUCH OF THE
SOUTHERN 2/3 OR SO OF THE REGION. SHORT RANGE GUIDANCE AGREES THAT
THE FRONT WILL CLEAR MY SERN ZONES BY NIGHTFALL BEFORE BECOMING
STATIONARY YET AGAIN JUST SOUTH OF THE STATE.
THE BEST CHANCE FOR RAIN WILL BE OVER THE NORTHERN 1/2 OF THE CWA
AS THE FRONT SAGS SOUTH...WITH SHOWERS BEING MORE SPOTTY OVER
SOUTHERN LOCATIONS.
RECORD HIGHS FOR THE 27TH...
52F AT IPT AND 59F AT MDT.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
MON-DAY WILL BE QUITE CHILLY - BUT VERY NEARLY NORMAL - AS TEMPS
GO LITTLE UPWARD THROUGH THE DAY. NORTH WINDS WILL BRING IN SOME
DECENTLY COLD AIR FROM A LARGE HIGH PRESSURE AREA MOVING ACROSS
CANADA AND INTO NEW ENGLAND. THE COLD AIR IS THE MOST INTERESTING
CHALLENGE IN THIS FORECAST...AND MAYBE FOR THE NEXT WEEK-PLUS. HOW
DEEP THE COLD AIR CAN GET AND HOW PERSISTENT IT WILL BE AGAINST
THE WARM AIR ADVECTION FROM A VERY STRONG LOW PRESSURE AREA MOVING
UP FROM THE LOWER MS VALLEY. SE WINDS OF 40KTS AT 8H MONDAY WILL
INCREASE TO 60KTS AS THEY VEER TO COME FROM DUE SOUTH. THE
MOISTURE TRANSPORT RESULTS IN PWATS OF 3 STANDARD DEVIATIONS ABOVE
NORMAL...WHICH IS NOT MUCH COMPARED TO SUNDAY/S LOFTY VALUES.
HOWEVER...THE MOISTURE ROLLING OVERHEAD WILL LIKELY BE LIQUID
FALLING INTO THE SUB- FREEZING AIR IN THE LOWEST 2-4KFT.
THE TROUBLE WOULD BE RE-FROZEN/FREEZING PRECIP LATE IN THE DAY ON
MONDAY AND MONDAY NIGHT. THE COLDEST/DEEPEST COLD AIR WILL BE IN
THE NERN MTNS AND MAY GET TRAPPED IN CENTRAL PA. HOWEVER...THE
TEMP GUIDANCE AT THIS POINT IS SOLID WITH CONTINUITY AND KEEPS THE
SRN HALF OF THE AREA ABOVE FREEZING THROUGH THE PERIOD. THE RECORD
WARMTH OF RECENT TIMES AND WARM/WET GROUND WILL BE NEGATIVES TO
FREEZING RAIN. SREF MEMBER P-TYPES PAINT A HIGH LIKELIHOOD OF
SLEET VS. FZRA. IN THE PAST...FORECASTS OF IP HAVE BEEN OVERDONE
BY THE SREFS AND A GREAT UNCERTAINTY REMAINS AS TO WHAT THE P-TYPE
WILL BE AND HOW LONG IT COULD STAY SOMETHING OTHER THAN PLAIN
RAIN. WILL KEEP IT CLOSE TO THE GOING FCST...BUT MENTION LESS
FZRA. BY TUESDAY MORNING....THE TEMP PROFILES ARE ENTIRELY RAIN
SAVE FOR PERHAPS TIOGA CO. THE PRECIP DOES PASS THROUGH IN
12-15HRS. THE STORM DEVELOPS A SECONDARY LOW OVER MD/DE AND SHOULD
CUT THINGS OFF TUESDAY MORNING. HELD SOME CHC POPS THRU THE AFTN
TO ACCOUNT FOR TIMING UNCERTAINTY.
ANOTHER UPPER SHORT WAVE IS IN STORE FOR EARLY THU AND BRINGS
RAIN...THEN COLDER AIR FOR THE LATER PART OF THE WEEK. TEMPS
FINALLY GET COLD ENOUGH AND FLOW OUT OF THE W/NW TO GENERATE LOTS
OF LAKE EFFECT SNOW. LAKES TEMPS HAVE GOT TO BE MUCH ABOVE
NORMAL...WHICH SHOULD HELP GENERATE PLENTY OF INSTABILITY AND
MOISTURE FLUX. 8H TEMPS DROP INTO THE NEGATIVE DOUBLE-DIGITS FRI-
MON UNDER A VERY DEEP UPPER TROUGH.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
CONDITIONS WILL DETERIORATE FROM SW TO NE AS A SLOWLY ADVANCING
WARM FRONT APPROACHES FROM THE SOUTH. EASTERN TERMINALS WILL
REMAIN VFR INTO THE LATE AFTERNOON BEFORE CONDITIONS DROP THERE
AS WELL.
EXPECT WIDESPREAD IFR/MVFR OVERNIGHT ALONG WITH AREAS OF RAIN.
THERE COULD BE A THUNDERSTORM OVER NWRN AREAS AHEAD OF A COLD
FRONT THAT WILL ENTER THE AREA SUNDAY MORNING.
OUTLOOK...
SUN...IFR/MVFR WITH PERIODS OF RAIN. IMPROVING CONDITIONS...ESPECIALLY
OVER SOUTHERN TERMINALS.
MON...VFR EARLY WITH AREAS MVFR AND RAIN DEVELOPING FROM WEST TO
EAST IN THE AFTERNOON.
MON NIGHT...DETERIORATING CONDITIONS. RAIN DEVELOPING /POSSIBLY A
WINTRY MIX NORTH/.
TUE...RAIN SHOWERS TAPERING OFF. GENERALLY MVFR WITH SLOWLY
IMPROVING CONDITIONS.
WED-THU...MVFR LIKELY NW. VFR SE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...LA CORTE
SHORT TERM...LA CORTE
LONG TERM...DANGELO/MARTIN
AVIATION...LA CORTE
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
959 AM EST SAT DEC 26 2015
.SYNOPSIS...
A WARM FRONT WILL MOVE SLOWLY NORTHWARD THROUGH THE REGION TODAY
AND OVERNIGHT. SUNDAY LOOKS ANOTHER RECORD SETTING WARM DAY BEFORE
COLDER AIR MAKES A RETURN SUNDAY NIGHT INTO MONDAY.
A STORM DURING THE FIRST PART OF THE WORK WEEK COULD START OUT AS
A LIGHT WINTRY MIX OVER THE NORTHERN MOUNTAINS BEFORE CHANGING TO
BACK TO JUST RAIN BEFORE ENDING. TEMPERATURES WILL COOL OFF TO
NEAR NORMAL THROUGH THE REST OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE RADAR SHOWS A DISORGANIZED AREA OF MAINLY LIGHT RAIN FROM THE
CENTRAL MOUNTAINS NORTH AND EAST. THE HRRR SHOWS THIS DISORGANIZED
ACTIVITY MORE OR LESS CONTINUING THROUGHOUT THE DAY BEFORE A
STEADIER AND MORE WIDESPREAD SHIELD OF RAIN SPREADS INTO THE
REGION AFTER DARK.
LOOK FOR AN UNSETTLED DAY WITH HIGHS GENERALLY IN THE 40S TO
LOWER 50S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/...
FRONT STAYS PRETTY MUCH STUCK TO THE SOUTH OF THE STATE UNTIL
LATER AT NIGHT WHEN IT COULD SLIDE THRU THE WRN MTNS AND THE SE.
HAVE PAINTED NEAR STEADY/RISING TEMPS FOR THE LATTER HALF OF THE
NIGHT THERE. THE AIRMASS WILL ONCE AGAIN HAVE THE POTENTIAL TO
PRODUCE RECORD MAXES - ESP CONSIDERING THE LOW-HANGING FRUIT OF
52F AT IPT AND 59F AT MDT FOR CURRENT RECORD MAXES ON THE 27TH.
HAVE PAINTED MAXES WELL ABOVE THE CURRENT RECORDS. BUST POTENTIAL
LIES IN HOW MUCH CLOUD COVER AND WHEN ANY RAIN SHOWERS DROP DOWN
FROM THE NW. SPEAKING OF POPS/WX...THE FRONT DOES NOT GO
FAR...STOPPING ABOUT LAKE ERIE AND A WAVE RIDES NE ALONG IT ON
SUNDAY/NIGHT. THIS WAVE SHOVES THE COLDER AIRMASS IN FROM THE WEST
SUNDAY NIGHT. BUT MINS WILL REMAIN 10-15F ABOVE NORMALS.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
MON-DAY WILL BE QUITE CHILLY - BUT VERY NEARLY NORMAL - AS TEMPS
GO LITTLE UPWARD THROUGH THE DAY. NORTH WINDS WILL BRING IN SOME
DECENTLY COLD AIR FROM A LARGE HIGH PRESSURE AREA MOVING ACROSS
CANADA AND INTO NEW ENGLAND. THE COLD AIR IS THE MOST INTERESTING
CHALLENGE IN THIS FORECAST...AND MAYBE FOR THE NEXT WEEK-PLUS. HOW
DEEP THE COLD AIR CAN GET AND HOW PERSISTENT IT WILL BE AGAINST
THE WARM AIR ADVECTION FROM A VERY STRONG LOW PRESSURE AREA MOVING
UP FROM THE LOWER MS VALLEY. SE WINDS OF 40KTS AT 8H MONDAY WILL
INCREASE TO 60KTS AS THEY VEER TO COME FROM DUE SOUTH. THE
MOISTURE TRANSPORT RESULTS IN PWATS OF 3 STANDARD DEVIATIONS ABOVE
NORMAL...WHICH IS NOT MUCH COMPARED TO SUNDAY/S LOFTY VALUES.
HOWEVER...THE MOISTURE ROLLING OVERHEAD WILL LIKELY BE LIQUID
FALLING INTO THE SUB- FREEZING AIR IN THE LOWEST 2-4KFT.
THE TROUBLE WOULD BE RE-FROZEN/FREEZING PRECIP LATE IN THE DAY ON
MONDAY AND MONDAY NIGHT. THE COLDEST/DEEPEST COLD AIR WILL BE IN
THE NERN MTNS AND MAY GET TRAPPED IN CENTRAL PA. HOWEVER...THE
TEMP GUIDANCE AT THIS POINT IS SOLID WITH CONTINUITY AND KEEPS THE
SRN HALF OF THE AREA ABOVE FREEZING THROUGH THE PERIOD. THE RECORD
WARMTH OF RECENT TIMES AND WARM/WET GROUND WILL BE NEGATIVES TO
FREEZING RAIN. SREF MEMBER P-TYPES PAINT A HIGH LIKELIHOOD OF
SLEET VS. FZRA. IN THE PAST...FORECASTS OF IP HAVE BEEN OVERDONE
BY THE SREFS AND A GREAT UNCERTAINTY REMAINS AS TO WHAT THE P-TYPE
WILL BE AND HOW LONG IT COULD STAY SOMETHING OTHER THAN PLAIN
RAIN. WILL KEEP IT CLOSE TO THE GOING FCST...BUT MENTION LESS
FZRA. BY TUESDAY MORNING....THE TEMP PROFILES ARE ENTIRELY RAIN
SAVE FOR PERHAPS TIOGA CO. THE PRECIP DOES PASS THROUGH IN
12-15HRS. THE STORM DEVELOPS A SECONDARY LOW OVER MD/DE AND SHOULD
CUT THINGS OFF TUESDAY MORNING. HELD SOME CHC POPS THRU THE AFTN
TO ACCOUNT FOR TIMING UNCERTAINTY.
ANOTHER UPPER SHORT WAVE IS IN STORE FOR EARLY THU AND BRINGS
RAIN...THEN COLDER AIR FOR THE LATER PART OF THE WEEK. TEMPS
FINALLY GET COLD ENOUGH AND FLOW OUT OF THE W/NW TO GENERATE LOTS
OF LAKE EFFECT SNOW. LAKES TEMPS HAVE GOT TO BE MUCH ABOVE
NORMAL...WHICH SHOULD HELP GENERATE PLENTY OF INSTABILITY AND
MOISTURE FLUX. 8H TEMPS DROP INTO THE NEGATIVE DOUBLE-DIGITS FRI-
MON UNDER A VERY DEEP UPPER TROUGH.
&&
.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
CONDITIONS WILL DETERIORATE FROM SW TO NE AS A SLOWLY ADVANCING
WARM FRONT APPROACHES FROM THE SOUTH. NORTHERN AND EASTERN
TERMINALS WILL REMAIN VFR INTO THE AFTERNOON BEFORE CONDITIONS
DROP THERE AS WELL.
OUTLOOK...
SUN...IFR/MVFR WITH PERIODS OF RAIN. IMPROVING CONDITIONS SE ON
SUN. LLWS.
MON...VFR WITH AREAS MVFR.
MON NIGHT...DETERIORATING CONDITIONS. RAIN DEVELOPING /POSSIBLY A
WINTRY MIX NORTH/. LLWS.
TUE...RAIN SHOWERS LIKELY. GENERALLY MVFR WITH SLOWLY IMPROVING
CONDITIONS.
WED...MVFR LIKELY NW. VFR SE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DANGELO/LA CORTE
NEAR TERM...DANGELO/LA CORTE
SHORT TERM...DANGELO
LONG TERM...DANGELO/MARTIN
AVIATION...ROSS/LA CORTE
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
602 PM CST SUN DEC 27 2015
.UPDATE...
FOR EVENING DISCUSSION.
&&
.DISCUSSION...
WILL BE UPDATING FORECAST TO MAKE SOME MINOR ADJUSTMENTS TO
OVERNIGHT LOW TEMPS. READINGS ARE ALREADY IN THE LOWER 50S
NORTHWEST, AND HRRR SHOWS TEMPS DROPPING TO AT LEAST 60 DEGS AS
FAR SOUTH AS BNA BY 08Z, BEFORE COLD FRONT STALLS AND THEN MOVES
BACK NORTH AS A WARM FRONT LATE TONIGHT.
OTHERWISE, LITTLE CHANGE TO PREVIOUS FORECAST.
&&
.AVIATION...
00Z TAF DISCUSSION.
BNA/CKV/CSV...SURFACE MAP AT 23Z SHOWS A WARM FRONT SITUATED JUST
EAST OF CKV, WITH IFR CIGS ON THE COOL SIDE OF THE BOUNDARY. LOOK
FOR THE FRONT TO LIFT NORTHWARD AGAIN OVERNIGHT, MAKING WAY FOR
TOMORROW`S LONG-AWAITED COLD FROPA. WE MAY SEE SOME LIGHT
PRECIPITATION OVERNIGHT CLOSE TO THE WARM FRONT, BUT THE BULK OF
THE ACTIVE WEATHER WILL HOLD OFF UNTIL AFTER 12Z WITH THE MAIN
FRONT. ALSO, LOOK FOR LLWS IN ADVANCE OF THE COLD FRONT, WITH
ABOVE-SURFACE WINDS INCREASING AS THE UPPER LOW DRAWS CLOSER.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH FROM MONDAY MORNING THROUGH MONDAY EVENING FOR
BEDFORD-CANNON-CHEATHAM-CLAY-COFFEE-CUMBERLAND-DAVIDSON-DE KALB-
DICKSON-FENTRESS-GILES-GRUNDY-HICKMAN-HOUSTON-HUMPHREYS-JACKSON-
LAWRENCE-LEWIS-MACON-MARSHALL-MAURY-MONTGOMERY-OVERTON-PERRY-
PICKETT-PUTNAM-ROBERTSON-RUTHERFORD-SMITH-STEWART-SUMNER-
TROUSDALE-VAN BUREN-WARREN-WAYNE-WHITE-WILLIAMSON-WILSON.
&&
$$
SHORT TERM/AVIATION........08
LONG TERM..................19
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1134 PM CST FRI DEC 25 2015
.UPDATE...
FOR 06Z AVIATION DISCUSSION.
&&
.DISCUSSION...
WARM FRONT CONTINUES TO MOVE SLOWLY NORTHWARD ACROSS MIDDLE
TENNESSEE, WITH NASHVILLE STILL NORTH OF THE BOUNDARY. THE ONLY
PRECIPITATION SHOWING UP ON RADAR IS LOCATED ALONG THE PLATEAU,
ALTHOUGH THE HRRR SHOWS SOME RE-DEVELOPMENT AFTER MIDNIGHT WITH
THE PASSAGE OF THE WARM FRONT. WAS HOPING THE WARMER AIR MIGHT
LOWER RH VALUES AND REDUCE OUR CHANCE OF DENSE FOG, BUT DEW POINTS
ARE COMING RIGHT UP WITH THE TEMPS, SO DEW POINT SPREADS EVEN IN
THE WARM SECTOR ARE RUNNING ZERO OR CLOSE TO ZERO. HAVE ALREADY
INCLUDED PATCHY DENSE FOG IN THE GRIDS, AND WE WILL MONITOR IN
CASE AN ADVISORY IS NEEDED. HAVE MADE ADJUSTMENTS TO LOW TEMPS TO
COME MORE IN LINE WITH CURRENT OBS, AS TEMPS OVERNIGHT WILL LIKELY
INCREASE SLIGHTLY AS THE WARM FRONT LIFTS FARTHER NORTHWARD.
&&
.AVIATION...
06Z TAF DISCUSSION.
THE WARM FRONT IS SLOWLY WORKING NORTH ACROSS THE AREA. VIS
SHOULD IMPROVE SLOWLY OVERNIGHT FOR BNA AND INTO THE DAWN HOURS
FOR CKV AS THE FRONT SLIDES NORTH. WITH THE FRONT.. SOME
SCATTERED SHOWERS AND THUNDERSTORMS WILL BE AROUND. CIGS SHOULD
IMPROVE TO MVFR FOR THE AFTERNOON AND EVENING HOURS AT ALL THREE
TERMINALS. WINDS WILL CONTINUE TO VEER FOR CKV AND BNA TO THE
SOUTH AND INCREASE TO THE 5-10 KT RANGE. CSV IS ALREADY SOUTH OF
THE BOUNDARY AND IS EXPERIENCING SOUTH WINDS AND VFR CIG AND VIS.
CSV VIS MAY DROP WITH A COUPLE PASSING SHOWERS AND THUNDERSTORMS
DURING THE MORNING HOURS.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
FLOOD WATCH UNTIL 6 AM CST SATURDAY FOR BEDFORD-CANNON-CLAY-
COFFEE-CUMBERLAND-DAVIDSON-DE KALB-FENTRESS-GILES-GRUNDY-HICKMAN-
JACKSON-LAWRENCE-LEWIS-MACON-MARSHALL-MAURY-OVERTON-PERRY-
PICKETT-PUTNAM-RUTHERFORD-SMITH-TROUSDALE-VAN BUREN-WARREN-WAYNE-
WHITE-WILLIAMSON-WILSON.
&&
$$
SHORT TERM/AVIATION........10/REAGAN
LONG TERM..................08
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1149 PM EST FRI DEC 25 2015
.SYNOPSIS...
A FRONTAL BOUNDARY WILL STALL OVER THE MID ATLANTIC REGION TONIGHT
AND LIFT NORTHWARD ON SATURDAY. SUNDAY AND MONDAY...A SERIES OF
STRONG LOW PRESSURE SYSTEMS WILL TRACK FROM THE SOUTHERN PLAINS TO
THE GREAT LAKES.
&&
.NEAR TERM /THROUGH SATURDAY/...
AS OF 1135 PM EST FRIDAY...
EXPECT A NARROW SLIVER OF SHOWERS FROM NE TN INTO THE FOOTHILLS OF
VA EARLY OVERNIGHT...WITH SOME INCREASE TOWARD MORNING OVER THE NC
MTNS AS BETTER UPPER DIVERGENCE ARRIVES. STILL LOOKS MOSTLY A
LIGHT TO AT TIMES MODERATE RAIN...WITH NEWER MODELS COMING IN
INDICATING BEST SLUG OF RAINFALL SATURDAY TO PUSH ACROSS ERN KY
INTO CENTRAL WV...SKIRTING THE SE WV MTNS. FOR THE REST OF THE
NIGHT CUT POPS BACK MORE AND LOWERED QPF.
PREVIOUS MID EVENING DISCUSSION...
CANCELLED THE FLASH FLOOD WATCH...AS HEAVIER RAIN THREAT HAS ENDED
AND DO NOT SEE ANY GOOD SIGNALS UPSTREAM FOR A NEAR TERM FLASH
FLOOD THREAT THROUGH TONIGHT. WILL HAVE TO WATCH OVER THE NC
MOUNTAINS IF SURGE OF MOISTURE WITH NEXT AREA OF UPPER DIVERGENCE
OVER GA/AL CAN GET ENHANCED OVERNIGHT. THINK THE RAIN WILL BE
MODERATE AT BEST...BUT IF TRENDS FOR DEEPER CONVECTION OCCUR
ANOTHER FLASH FLOOD WATCH WOULD BE NEEDED.
SAME GOES FOR SE WV INTO THE MOUNTAINS OF FAR SW VA FOR
SATURDAY...AS MODEL TRENDS GIVE THIS AREA ANOTHER ONE HALF TO ONE
INCH POTENTIALLY SATURDAY.
CUT BACK POPS OVERNIGHT FAVORING THE FAR SW VA/NW NC MTNS INTO SRN
VA AS HIGHER CORRIDOR OF RAINFALL CHANCES. FOG IS STILL LIKELY AS
SOME LOW LVL CLOUD COVER SCATTERS OUT ESPECIALLY OVER THE
GREENBRIER VALLEY INTO THE NEW RIVER VALLEY. ATTM...STILL NOT
SEEING ANY DECENT LOW VSBY COVERAGE FOR DENSE FOG ADVISORY OR
EVENT A STATEMENT.
PREVIOUS DISCUSSION FROM EARLY EVENING...
GOING TO CUT POPS BACK SOME OVER THE NW AS NARROW BAND OF SHOWERS
IS MAINLY LINED UP ALONG A ZONE OF LOW LVL CONVERGENCE FROM TRI-
BCB...EAST TO LYH. THE LATEST GFS PLUS HIGH-RES MODELS SHOWING
MORE OF A SWD SHIFT THROUGH THIS EVENING. WILL HAVE TO WATCH THE
DEEPER CONVECTION OVER MID TN EARLY THIS EVENING...AND SEE HOW IT
SHIFTS EAST OR NORTHEAST ALONG THE FRONTAL BOUNDARY.
STILL THINK FOG WILL BECOME AN ISSUE OVER THE WEST THROUGH
TONIGHT. WILL HAVE TO MONITOR HOW WIDESPREAD AND DENSE FOG
GETS...TO DECIDE BETWEEN A DENSE FOG ADVISORY VS SPECIAL WX
STATEMENT.
PREVIOUS AFTERNOON DISCUSSION...
A FRONTAL BOUNDARY WITH SEVERAL WAVES OF LOW PRESSURE STALLS THIS
EVENING INTO TONIGHT ACROSS THE REGION AND THEN PUSHES NORTHWARD ON
SATURDAY. AN AREA OF LOW PRESSURE IN WEST VIRGINIA THIS AFTERNOON
WILL LIFT NORTHEAST AND REACH THE JERSEY SHORE TONIGHT. A SECOND
AREA OF LOW PRESSURE WILL ROTATE NORTHWARD ALONG THE BOUNDARY
TONIGHT WITH ADDITIONAL SHOWERS. THE DAY 1 EXCESSIVE RAINFALL PLACED
THE WESTERN HALF OF THE FORECAST AREA UNDER A SLIGHT RISK. CURRENT
WSR-88D SHOWED A BAND OF SHOWERS AND THUNDERSTORMS FROM WEST
VIRGINIA SOUTHWARD TO EASTERN AND MIDDLE TENNESSEE. ELECTED TO
EXTEND OUR FLASH FLOOD WATCH UNTIL MIDNIGHT...GIVEN THAT WITH RECENT
RAINFALL AND LOW FFG...IT WILL NOT TAKE MUCH TO PRODUCE FLASH
FLOODING IN THE REGION. DAY ONE CONVECTIVE OUTLOOK STILL SHOWS A
MRGL THREAT FOR SEVERE...WITH THE POTENTIAL FOR LOCALLY STRONG WIND
GUSTS INTO THIS EVENING. MCS OVER EASTERN KENTUCKY/TENNESSEE IS
PROGGED TO SPREAD EAST OF THE BLUE RIDGE LATER TODAY...WHERE IT WILL
INTERACT WITH A SEASONABLY WARM AND MOIST AIR MASS. SEVERE THREAT
WILL BE HINDER BY POOR WEAK INSTABILITY...AND POOR LAPSE RATES OVER
OUR AREA. THE HIRESW-ARW...RNK WRF AND HRRR TAKE THE AREA OF
CONVECTION TO OUR WEST AND MOVED IT EASTWARD ACROSS OUR FORECAST
AREA THIS AFTERNOON INTO TONIGHT. THE GFS...NAM AND ECMWF DROP THE
CONVECTION WITH THE FRONTAL BOUNDARY SOUTH THROUGH 00Z TO 03Z THIS
EVENING. IN ANY CASE...PLAYED THE HIGHEST POPS ACROSS THE
NORTHWEST...WITH THE LOWEST ALONG THE EASTERN SLOPES OF THE
SOUTHERN BLUE RIDGE MOUNTAINS. IT WILL BE ANOTHER MILD
NIGHT...WITH LOW TEMPERATURES FROM THE LOWER 50S IN THE NORTHERN
MOUNTAINS TO THE LOWER 60S IN THE PIEDMONT.
OUR UNSEASONABLY WARM AND UNSETTLED PATTERN WILL CONTINUE SATURDAY.
THE UPPER PATTERN WILL FEATURE AN EASTERN RIDGE AS A CLOSED LOW
DEVELOPS OVER TEXAS AND THEN EJECTS INTO THE OHIO VALLEY. THIS WILL
PUSH THE FRONTAL BOUNDARY...WHICH HAS BEEN WAVERING AROUND THE
REGION FOR THE LAST SEVERAL DAYS...BACK TO THE NORTH AND KEEP THE
BEST CHANCES FOR PRECIPITATION...MAINLY NORTH OF ROUTE 460. HIGH
TEMPERATURES SATURDAY WILL RANGE FROM THE LOWER 60S IN THE NORTHERN
MOUNTAINS TO LOWER AND MID 70S IN THE PIEDMONT.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/...
AS OF 130 PM EST FRIDAY...
RELATIVE BREAK IN THE WET WEATHER EXPECTED OVER THE BLACKSBURG
FORECAST AREA FROM SATURDAY NIGHT THROUGH AT LEAST EARLY SUNDAY
NIGHT WITH ONLY SPOTTY WARM SECTOR SHOWERS POSSIBLE AS VERY STRONG
TROPICAL RIDGE OF HIGH PRESSURE OFF THE SE COAST OF THE NATION
DEFLECTS NORTHERN STREAM ENERGY AND MORE ROBUST PRECIPITATION FIELDS
CLOSER TO BAROCLINIC ZONE TO THE NORTH OF THE AREA. ANY RESIDUAL
COOL WEDGE ACROSS NORTHEASTERN PORTION OF THE FORECAST AREA SHOULD
RETREAT NORTH AND OUT OF THE AREA BY OR SHORTLY AFTER DAYBREAK ON
SUNDAY AS SE COASTAL RIDGE STRENGTHENS.
HOWEVER...SITUATION WILL BEGIN TO CHANGE LATER SUNDAY NIGHT INTO
MONDAY AS YET ANOTHER...AND THIS TIME STRONGER NORTHERN STREAM WAVE
MOVES EAST THROUGH THE GREAT LAKES AND NEW ENGLAND...SUPPORTING
SOUTHEASTWARD PUSH OF COOLER HIGH PRESSURE INTO SOUTHEASTERN
CANADA...WHICH THEN RIDGES SOUTHWEST INTO THE MID ATLANTIC REGION
MONDAY AFTERNOON INTO MONDAY NIGHT. MEANWHILE...YET ANOTHER
FORMIDABLE LOW LATITUDE CLOSED LOW WILL DRIFT NORTHEAST ON THE
WESTERN PERIPHERY OF THE UPPER RIDGE ALONG THE SE COAST...GRADUALLY
LIFTING AND FILLING AS IT MOVES UP THROUGH THE MS/TN/OH VALLEYS.
APPROACH OF THE WESTERN SYSTEM...AND MOVEMENT OF COOL SURFACE HIGH
PRESSURE TO AN OFFSHORE POSITION TO OUR NORTHEAST WILL RESULT IN
SLOWLY VEERING LOWER TROPOSPHERIC WINDS BACK INTO AN UPSLOPE
COMPONENT ON MONDAY...WHICH SHOULD BEGIN THE NEXT ROUND OF
WIDESPREAD PRECIPITATION FOR THE REGION. PRECIPITATION WILL
INITIALLY BE CONFINED TO LIGHT RAIN AND DRIZZLE ACROSS THE EASTERN
FLANKS OF THE APPALACHIANS LATE SUNDAY NIGHT INTO EARLY MONDAY AS
UPSLOPE COMPONENT INCREASES...BUT THEN EXPAND TO A WIDESPREAD
COVERAGE ACROSS THE ENTIRE FORECAST AREA MONDAY AFTERNOON INTO
MONDAY NIGHT AS UPWARD VERTICAL MOTION FIELDS INTENSIFY AS A RESULT
OF INCREASING WARM MOIST ADVECTION AND APPROACH OF RIGHT ENTRANCE
REGION OF UPPER JET MAXIMA.
WITH GROUND CONDITIONS ALREADY SATURATED...AND WATER LEVELS IN AREA
STREAMS/CREEKS AND RIVERS ALREADY RUNNING HIGH FROM RECENT RAINS...
THREAT FOR ADDITIONAL FLOODING/FLASH FLOODING WILL AGAIN EXIST FROM
MONDAY AFTERNOON INTO MONDAY NIGHT UNTIL CHANGE OF AIRMASS OCCURS
WITH COLD FRONTAL PASSAGE LATE MONDAY NIGHT OR AROUND DAYBREAK ON
TUESDAY.
UNTIL THEN...TEMPERATURES THROUGH THE ENTIRE SHORT TERM PERIOD WILL
CONTINUE TO REMAIN CLOSE TO OR EXCEED RECORD LEVELS...BOTH FOR VERY
HIGH NIGHTTIME LOWS...WHICH WILL REMAIN NEARLY 30F ABOVE SEASONAL
NORMALS AND AROUND 15F HIGHER THAN WHAT WOULD NORMALLY BE EXPECTED
FOR A DAYTIME HIGH TEMPERATURE...WITH DAYTIME HIGH TEMPERATURES AT
LEAST 20F ABOVE SEASONAL NORMALS...AGAIN BREAKING RECORDS. REFER TO
CLIMATOLOGICAL SECTION FOR SPECIFICS.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 140 PM EST FRIDAY...
TUESDAY WILL FEATURE SOME LEFT OVER RAIN SHOWERS BEFORE THE FRONT
CAN MAKE ITS PUSH THROUGH THE REGION. WEDNESDAY LOOKS TO BE A DRIER
DAY EARLY BEFORE THE NEXT SYSTEM MOVES UP AND BRINGS ADDITIONAL RAIN
SHOWERS LATE WEDNESDAY NIGHT AND INTO THE DAY ON THURSDAY. TEMPS
TUESDAY THROUGH THURSDAY WILL REMAIN ABOVE NORMAL. TUESDAY LOOKS TO
BE THE WARMEST DAY OF THE PERIOD WITH HIGHS IN THE UPPER 50S TO
LOWER 60S...AND THEN ABOUT 5 DEGREES COOLER ON WEDNESDAY AND
THURSDAY.
A BIG PATTERN SHIFT SETS UP FOR LATE IN THE WEEK AS A
STRONG RIDGE SETS UP OUT WEST AND A TROUGH BEGINS TO DIG IN ACROSS
THE EASTERN HALF OF THE COUNTRY BRINGING MUCH COLDER AIR TO THE
REGION. SEVERAL WAVES OF ENERGY WILL RIPPLE ACROSS THROUGH NEXT
WEEKEND. MOISTURE LOOKS LIMITED BUT COULD BE ENOUGH TO SQUEAK OUT
SOME NORTHWEST FLOW PRECIP ACROSS THE WESTERN UPSLOPE
AREAS...OTHERWISE THE REST OF THE REGION LOOKS TO BE COOLER AND DRY
FOR NEXT WEEKEND.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
AS OF 1143 PM EST FRIDAY...
EXPECT TO SEE A VARIABLE AVIATION FORECAST OVERNIGHT WITH SOME
LOCATIONS DROPPING TO IFR OR WORSE VSBYS AND/OR CIGS. RAIN SHOWERS
WILL BE LIMITED BUT THERE IS STILL PLENTY OF MOISTURE IN ALL
LEVELS AT TIMES. SOME BREAKS IN THE LOWER CLOUD COVER HAS ALLOWED
FOR DENSE FOG TO FORM AT LWB...WITH THINK BCB AND POTENTIALL ROA
TO LYH/DAN COULD DROP TO 1/2 TO 1SM EARLY IN THE MORNING.
BEST BET FOR RAIN SHOWER WILL BE IN THE LWB/BLF CORRIDOR SATURDAY
WITH SCATTERED THREAT FURTHER EAST. AS HIGH PRESSURE MOVES OVER
THE NORTHEAST IT WEDGES SOUTHWEST INTO THE MOUNTAINS...AND NOW THE
NAM/GFS INDICATE THAT MOST TAF SITES WILL NOT BREAK OUT OF LOW END
MVFR SATURDAY...SO WENT A LITTLE MORE PESSIMISTIC IN THE
TERMINALS.
CONFIDENCE IS HIGH THAT MOST...IF NOT ALL TAF SITES STAY MVFR OR
WORSE THIS PERIOD...THOUGH COULD SEE BLF GO VFR THROUGH THE
MORNING.
.EXTENDED AVIATION DISCUSSION...
THE CHANCE OF SHOWERS AND SUB-VFR CONDITIONS WILL CONTINUE INTO
SAT NIGHT ANS SUNDAY THOUGH SHOWERS WILL BE LIMITED. WE ARE LESS
LIKELY TO PERSIST IN THE IFR OR WORSE VALUES AS ATMOSPHERE WILL BE
A LITTLE BETTER MIXED AND FREQUENCY OF SHOWERS MUCH LESS WITH NO
KEY FEATURES TO HELP LIFT THE MOIST ATMOSPHERE.
BEYOND THIS WEEKEND...MODELS CONTINUE TO VARY BUT SHOWING BETTER
THREAT OF SHOWERS AGAIN BY LATE MONDAY INTO TUESDAY WITH VFR TO
IFR AT TIMES.
&&
.HYDROLOGY...
AS OF 1006 PM EST FRIDAY...
FLASH FLOOD WATCH CANCELLED...BUT STILL FLOOD WARNINGS ALONG THE
DAN RIVER AND AT RANDOLPH ON THE ROANOKE RIVER. THE CLINCH AND
NORTH FORK OF THE HOLSTON IN FAR SW VA ARE ALSO RISING BUT WITH
LACK OF APPRECIABLE RAIN THROUGH EARLY OVERNIGHT...THINK THESE
RIVERS STAY BELOW FLOOD STAGE.
&&
.CLIMATE...
AS OF 230 PM EST FRIDAY...
WITH THE CONTINUING VERY WARM AIRMASS IN PLACE FOR THE NEXT
SEVERAL DAYS... MANY DAILY MAX TEMPERATURE RECORDS AS WELL AS HIGH
MIN TEMPERATURE RECORDS ARE LIKELY TO BE SET. FOR REFERENCE...HERE
ARE RECORDS FOR OUR CLIMATE STATIONS FOR THE NEXT SEVERAL DAYS.
SATURDAY 12/26/2015
SITE MAXT YEAR MINT YEAR LOMAX YEAR HIMIN YEAR
KBLF 62 1987 -3 1983 16 1977 55 1982
KDAN 75 1982 2 1983 18 1983 57 1964
KLYH 72 1922 1 1983 22 1914 58 1964
KROA 70 1964 3 1980 23 1985 56 1982
KRNK 64 1982 -8 1985 9 1983 50 1982
SUNDAY 12/27/2015
SITE MAXT YEAR MINT YEAR LOMAX YEAR HIMIN YEAR
KBLF 69 2008 9 1977 20 2010 52 1982
KDAN 77 1982 6 1983 27 1985 54 1964
KLYH 71 1971 0 1914 21 1925 50 1940
KROA 69 1984 -3 1914 25 1935 52 1940
KRNK 67 2008 -6 1985 20 1985 52 1964
MONDAY 12/28/2015
SITE MAXT YEAR MINT YEAR LOMAX YEAR HIMIN YEAR
KBLF 67 1984 4 1977 20 1995 53 1984
KDAN 72 1971 13 1966 28 1950 54 2008
KLYH 76 1984 6 1977 26 1950 51 1959
KROA 75 1984 4 1925 25 1925 51 1984
KRNK 66 1984 6 1977 28 1995 42 1959
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS/KK
NEAR TERM...KK/WP
SHORT TERM...WERT
LONG TERM...CF
AVIATION...AMS/KK/WP
HYDROLOGY...AMS/KK/WP
CLIMATE...AMS/RCS
AREA FORECAST DISCUSSION
NWS SEATTLE WA
902 AM PST SAT DEC 26 2015
.SYNOPSIS...AN UPPER LEVEL RIDGE CROSSING WESTERN WASHINGTON SHOULD
PRODUCE MOSTLY CLOUDY AND MAINLY DRY WEATHER TODAY. A WEAKENING
FRONTAL SYSTEM WILL SPREAD RAIN INLAND LATER TONIGHT AND SUNDAY
MORNING. TEMPERATURES WILL BE COLD ENOUGH FOR A RAIN SNOW MIX IN
PLACES. A WEAK UPPER LEVEL TROUGH WILL FOLLOW WITH SCATTERED SHOWERS
SUNDAY AFTERNOON. SHOWERS WILL DIMINISH ON MONDAY. ANOTHER WEAK
SYSTEM MAY BRING A LITTLE RAIN TO THE AREA TUESDAY AFTERNOON THROUGH
WEDNESDAY. A STRONG UPPER LEVEL RIDGE SHOULD BRING DRY WEATHER LATE
THIS WEEK.
&&
.SHORT TERM...A PROGRESSIVE UPPER RIDGE EXTENDS FROM NORTHERN
BRITISH COLUMBIA INTO THE OFFSHORE WATERS OF CENTRAL CALIFORNIA THIS
MORNING. THERE IS ENOUGH FLOW THROUGH THE RIDGE FOR MOISTURE TO
STREAM THROUGH...AND ABUNDANT CLOUD COVER IS SEEN OVER THE AREA THIS
MORNING. LITTLE IN THE WAY OF FOG IS BEING SEEN.
KLGX RADAR SHOWS AN AREA OF LIGHT RAIN EXTENDING FROM CENTRAL
VANCOUVER ISLAND SOUTHWARD THROUGH THE FAR OUTER COASTAL ZONES THIS
MORNING AND A NARROW BAND OF VERY LIGHT RAIN EXTENDS FROM ABOUT KUIL
SOUTHWESTWARD. THE INCOMING 12Z NAM...12Z GFS20...AND HRRR SHOW THIS
VERY LIGHT PRECIPITATION REMAINING FROM AROUND THE NORTH COASTAL
ZONE OFFSHORE THROUGH EARLY THIS EVENING.
WILL UPDATE THE FORECAST FOR TODAY TO REMOVE FOG FROM ALL AREAS
EXCEPT THE CHEHALIS GAP FROM ABOUT SHELTON AND BRINNON TO HOQUIAM
AND TO REMOVE PRECIPITATION FROM THE INTERIOR ZONES THIS AFTERNOON.
RIDGING OVER THE PACNW AND COLD AIR ALOFT FROM ABOUT 40N NORTHWARD
AT 145W PROMISES TO TAKE THE INCOMING TROUGH AND SPLIT IT TAKING THE
BRUNT OF IT DOWN INTO OREGON AND CALIFORNIA. THE NEGATIVE TILT OF
THE INCOMING SPLITTING SYSTEM WILL RESULT IN LOW LEVEL PRES
GRADIENTS REMAINING RATHER NELY. THIS MEANS THAT COOL AIR FLOWING
OUT FROM THE FRASER RIVER VALLEY IN WESTERN WHATCOM COUNTY MAY ALLOW
PRECIPITATION TO START BRIEFLY AS SNOW OR A RAIN SNOW MIX AROUND THE
BELLINGHAM AREA...AND COLD AIR DAMMING AROUND THE HOOD CANAL WHERE
1000-850 MB THICKNESSES AROUND 1299M ARE EXPECTED SUNDAY MORNING
WITH ABOUT 0.3 INCHES OF PRECIPITATION...MAY RESULT IN SOME SNOW OR
A RAIN SNOW MIX AROUND SHELTON AND BRINNON SUNDAY MORNING.
PRECIPITATION WILL SPREAD INTO WESTERN WASHINGTON SUNDAY MORNING AS
A COLD RAIN WITH LOW LEVEL THICKNESSES AROUND 1304M. THE FRONT WILL
MOVE INTO THE CASCADES SUNDAY EVENING TURNING PRECIPITATION TO
SCATTERED SHOWERS...THEN SHOWERS WILL BECOME ISOLATED ON MONDAY WITH
A WEAK TROUGH PUSHING INLAND.
MONDAY NIGHT WILL BE MAINLY DRY AS A WEAK AND DIRTY UPPER RIDGE
MOVES ACROSS THE AREA.
OTHER THAN CHANGES TO THE FIRST PERIOD MENTIONED ABOVE...CURRENT
FORECASTS LOOK GOOD. ALBRECHT
.LONG TERM...FROM THE PREVIOUS LONG TERM DISCUSSION...THE GFS AND
ECMWF HAVE A SMALL WEAK UPPER LEVEL LOW MOVING SE ALONG THE B.C.
COAST ON TUESDAY WITH A LITTLE LIGHT PRECIP OUT AHEAD OF IT. THE
ECMWF IS A LITTLE FASTER WITH THE LOW...BUT AT LEAST THE MODELS HAVE
THE SAME GENERAL IDEA.
A MODERATELY HIGH AMPLITUDE UPPER LEVEL RIDGE FORMS OFFSHORE BEHIND
THE LOW...THEN MOVES OVER THE COAST BY WEDNESDAY AFTERNOON TO START
A DRY PERIOD. OVERALL THE MODELS HAVE THE RIDGE DOMINATING THROUGH
NEXT WEEKEND...BUT THERE APPEAR TO BE A COUPLE OF CLOSE CALLS WITH
VERY WEAK SYSTEMS. WITH LESS CLOUD COVER UNDER THE RIDGE IT LOOKS
LIKE A GOOD FOG PRODUCER. THERE WILL BE OFFSHORE FLOW BUT PROBABLY
NOT ENOUGH WIND TO COMPLETELY SCOUR OUT THE MORNING FOG IN SOME
AREAS. KAM
&&
.AVIATION...WESTERLY FLOW ALOFT TODAY WILL TURN SOUTHWESTERLY
TONIGHT AS A FRONT APPROACHES THE REGION. SOUTHEAST SURFACE WINDS
WILL INCREASE THIS AFTERNOON AND TONIGHT. AIR MASS IS MOIST AND
STABLE.
CLOUDS FROM THE APPROACHING SYSTEM HAVE BROUGHT CEILINGS INTO
WESTERN WASHINGTON...MAINLY AROUND 5K FT...WITH MORE CLOUD LAYERS
ABOVE THAT. THERE IS PATCHY IFR STRATUS AS WELL. THE STRATUS WILL
EVAPORATE BUT SOME LOWERING OF CEILINGS OVERALL WILL OCCUR TODAY...
AND MVFR CEILINGS WILL DEVELOP TONIGHT AS RAIN SLOWLY SPREADS
INLAND.
KSEA...DISCUSSION ABOVE APPLIES WITH VFR EXPECTED MOST OF TODAY AND
MVFR TONIGHT. RAIN LIKELY TO BEGIN AROUND 15Z SUNDAY AND CONTINUE
THROUGH THE DAY. SE WIND 4-8 KT THIS MORNING WILL INCREASE TO 8-12
KT THIS EVENING. CHB
&&
.MARINE...AN APPROACHING FRONT WILL INCREASE SOUTHEASTERLY WINDS TO
SMALL CRAFT ADVISORY STRENGTH OVER MOST WATERS TODAY. AS THE FRONT
NEARS THE COAST THERE WILL BE SOME HOURS OF GALE FORCE WINDS OVER
THE COAST. SOME RECENT MODELS ALSO HAVE GALE FORCE WINDS FOR A FEW
HOURS SUNDAY MORNING FOR THE EAST ENTRANCE AND NORTHERN INLAND
WATERS. A GALE WARNING IS IN EFFECT FOR THE COAST AND A GALE WATCH
HAS BEEN ISSUED FOR THE EAST ENTRANCE AND NORTHERN INLAND WATERS.
FLOW APPEARS RELATIVELY LIGHT ON MONDAY AND TUESDAY. CURRENT MODELS
BRING ANOTHER FRONT TUESDAY NIGHT AND WEDNESDAY. SMALL CRAFT
ADVISORIES OR GALE WARNINGS MAY BE NEEDED FOR THIS SYSTEM. CHB
&&
.HYDROLOGY...RIVER FLOODING IS NOT EXPECTED THE NEXT 7 DAYS.
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY UNTIL 4 PM PST THIS AFTERNOON FOR COASTAL
WATERS FROM CAPE FLATTERY TO JAMES ISLAND 10 TO 60 NM-
COASTAL WATERS FROM CAPE FLATTERY TO JAMES ISLAND OUT 10 NM-
COASTAL WATERS FROM JAMES ISLAND TO POINT GRENVILLE 10 TO
60 NM-COASTAL WATERS FROM JAMES ISLAND TO POINT GRENVILLE
OUT 10 NM-COASTAL WATERS FROM POINT GRENVILLE TO CAPE
SHOALWATER 10 TO 60 NM-COASTAL WATERS FROM POINT GRENVILLE
TO CAPE SHOALWATER OUT 10 NM.
GALE WARNING FROM 4 PM THIS AFTERNOON TO 4 PM PST SUNDAY FOR
COASTAL WATERS FROM CAPE FLATTERY TO JAMES ISLAND 10 TO 60
NM-COASTAL WATERS FROM CAPE FLATTERY TO JAMES ISLAND OUT 10
NM-COASTAL WATERS FROM JAMES ISLAND TO POINT GRENVILLE 10
TO 60 NM-COASTAL WATERS FROM JAMES ISLAND TO POINT
GRENVILLE OUT 10 NM-COASTAL WATERS FROM POINT GRENVILLE TO
CAPE SHOALWATER 10 TO 60 NM-COASTAL WATERS FROM POINT
GRENVILLE TO CAPE SHOALWATER OUT 10 NM.
SMALL CRAFT ADVISORY FOR ROUGH BAR FROM 3 PM THIS AFTERNOON TO 7
PM PST THIS EVENING FOR GRAYS HARBOR BAR.
GALE WATCH FROM LATE TONIGHT THROUGH SUNDAY AFTERNOON FOR EAST
ENTRANCE U.S. WATERS STRAIT OF JUAN DE FUCA-NORTHERN INLAND
WATERS INCLUDING THE SAN JUAN ISLANDS.
SMALL CRAFT ADVISORY UNTIL 4 AM PST SUNDAY FOR EAST ENTRANCE
U.S. WATERS STRAIT OF JUAN DE FUCA-NORTHERN INLAND WATERS
INCLUDING THE SAN JUAN ISLANDS.
SMALL CRAFT ADVISORY UNTIL 4 PM PST SUNDAY FOR ADMIRALTY INLET-
WEST ENTRANCE U.S. WATERS STRAIT OF JUAN DE FUCA.
&&
$$
WWW.WEATHER.GOV/SEATTLE
YOU CAN SEE AN ILLUSTRATED VERSION OF THIS DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
620 PM CST SUN DEC 27 2015
UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND MONDAY
ISSUED AT 240 PM CST SUN DEC 27 2015
THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW ARCTIC HIGH
PRESSURE CENTERED OVER THE NORTHERN GREAT PLAINS AND SOUTH-CENTRAL
CANADA EARLY THIS AFTERNOON. NORTHWEST WINDS AROUND THE HIGH
CONTINUE TO BRING CLOUDS OFF LAKE SUPERIOR...WHILE STEEP LOW LEVEL
LAPSE RATES ARE HELPING TO FILL IN ANY HOLES THAT DEVELOP IN THE
CLOUD COVER. SKIES CLEAR OVER FAR WESTERN WISCONSIN AND MINNESOTA
CLOSER TO THE SURFACE HIGH. LOOKING TO THE FAR SOUTHWEST...UPPER
LEVEL LOW PRESSURE IS MOVING EAST OVER THE RIO GRANDE. AS THIS LOW
TRACKS INTO THE GREAT LAKES LATE MONDAY AND EARLY TUESDAY...IMPACTS
FROM WINTRY WEATHER ARE THE MAIN FORECAST CONCERNS.
TONIGHT...MAINLY QUIET. ARCTIC HIGH PRESSURE WILL SLIDE NORTH OF
LAKE SUPERIOR WITH WINDS VEERING FROM NORTH TO NORTHEAST THROUGH THE
NIGHT. STILL THINK WILL SEE A PERIOD OF CLEARING OVER NORTHEAST AND
CENTRAL WI AS LOW CLOUDS LOOK DIURNALLY ENHANCED AWAY FROM THE SNOW
BELTS. LOW INVERSION HEIGHTS THEN SUPPORT NORTHEAST WINDS BRINGING
IN LOW CLOUDS OFF LAKES MICHIGAN AND SUPERIOR OVERNIGHT. A FEW
FLURRIES COULD MOVE ACROSS ALONG THE LAKESHORE. LOWS FALLING INTO
THE SINGLE DIGITS NORTH TO MID 20S LAKESIDE.
MONDAY...UPPER LEVEL LOW PRESSURE WILL BE GRADUALLY MOVING NORTHWARD
FROM EASTERN TEXAS INTO THE MID-MISSISSIPPI VALLEY. TO THE
NORTH...EAST WINDS WILL CONTINUE TO FUNNEL IN ARCTIC AIR ACROSS THE
WESTERN GREAT LAKES REGION. IF FLURRIES DEVELOP...THEY SHOULD
CONTINUE THROUGH THE EARLY AFTERNOON HOURS. OTHERWISE...SKIES
SHOULD BE MAINLY MOSTLY CLOUDY THROUGH MIDDAY. FORCING AHEAD OF THE
UPPER LOW WILL INCREASE QUICKLY DURING THE AFTERNOON. COUPLED JET
STRUCTURE COMBINED WITH STRONG MID-LEVEL FGEN WILL BRING A SWATH OF
PRECIP INTO CENTRAL AND EAST-CENTRAL WISCONSIN AFTER ABOUT 20-21Z.
PROGGED SOUNDINGS INDICATE THAT SOME SLEET MAY WORK IN WITH THE SNOW
RIGHT AS PRECIP ARRIVES. DID REMOVE THE RAIN MENTION ALONG THE
LAKESHORE SINCE LOW LEVEL TEMPS ARE VERY COLD. DUE TO THE SNOW AND
SLEET MIX COMBINED WITH GUSTY EAST WINDS IN EXCESS OF 30-35
MPH...THE EVENING COMMUTE COULD BECOME QUITE HAZARDOUS. WILL
UPGRADE THE WATCH TO A WINTER STORM WARNING AND START THE HEADLINE
AT 21Z. COULD SEE UP TO AN INCH OF SNOW IN SPOTS BY 6 PM.
.LONG TERM...MONDAY NIGHT THROUGH SUNDAY
ISSUED AT 240 PM CST SUN DEC 27 2015
WINTER STORM IMPACTS IN NORTH-CENTRAL AND NORTHEAST WISCONSIN
WILL CONTINUE THROUGH MONDAY EVENING INTO TUESDAY MORNING...
TAPERING OFF OVERNIGHT. COMPUTER MODELS ARE IN RELATIVELY GOOD
AGREEMENT ON TRACK AND TIMING OF THE LOW PRESSURE SYSTEM CENTER
MOVEMENT INTO WISCONSIN...WHICH CONTINUES TO PLACE THE FOX VALLEY
IN A SLEET-TO-SNOW TRANSITION AREA. ON MONDAY EVENING...IN
ADDITION TO THE ONGOING WINTRY PRECIPITATION...EAST WINDS WILL
GUST IN THE 30-40 MPH RANGE NEAR LAKE MICHIGAN AND THE BAY TO
START OFF THE EVENING...WITH GUSTS TO 30 MPH ELSEWHERE ACROSS THE
REGION. WINDS WILL THEN TAPER OFF AS THE LOW PRESSURE SYSTEM
WEAKENS OVERNIGHT INTO TUESDAY MORNING. FLURRIES WILL LINGER A
LITTLE WHILE ACROSS THE AREA TUESDAY MORNING AS THE REMNANTS OF
THE SYSTEM DEPART TO THE EAST.
ANOTHER WEAKER SYSTEM WILL BRING A CHANCE OF LIGHT SNOW ON
WEDNESDAY INTO WEDNESDAY EVENING. TEMPERATURES BY THE END OF THE
WORK WEEK SHOULD FALL TO NORMAL OR EVEN A FEW DEGREES BELOW
NORMAL.
&&
.AVIATION...FOR 00Z TAF ISSUANCE
ISSUED AT 619 PM CST SUN DEC 27 2015
SURFACE HIGH PRESSURE RIDGE WILL SKIRT THE NORTHERN PORTION OF THE
FORECAST AREA OVERNIGHT. NORTHERLY BOUNDARY LAYER FLOW OFF LAKE
SUPERIOR WILL BRING SCT-BKN MVFR CLDS ACROSS THE FAR NORTH FROM
TIME TO TIME ALONG WITH FLURRIES. WINDS WILL THEN TURN NORTHEASTERLY
BY MIDNIGHT BRINGING SOME SCT-BKN CLOUDS OFF LAKE MICHIGAN INTO
EASTERN WISCONSIN WHERE OCCASIONAL MVFR CIGS AND FLURRIES ARE ALSO
POSSIBLE AFTER ABOUT 06Z.
THEN...A LARGE AND STRONG LOW PRESSURE SYSTEM WILL APPROACH THE
FORECAST AREA FROM THE CENTRAL MISSISSIPPI VALLEY DURING THE DAY
ON MONDAY. AS THIS SYSTEM APPROACHES...EAST TO NORTHEAST WINDS
WILL INCREASE DURING THE MORNING. BY EARLY TO MID-AFTERNOON MONDAY
WIND GUSTS OF 30 TO 35 MPH ARE LIKELY ESPECIALLY OVER THE FOX
VALLEY AND LAKE SHORE AREAS. THE GUSTY EAST TO NORTHEAST WINDS
WILL CONTINUE INTO THE EVENING HOURS. A LARGE PRECIPITATION
SHIELD WILL ALSO PUSH NORTHWARD DURING THE AFTERNOON REACHING THE
SOUTHERN FOX VALLEY BY AROUND 22 UTC BRINGING IFR CONDITIONS. A
MIXTURE OF SNOW AND SLEET IS LIKELY...WITH SOME ACCUMULATING SLEET
BY THE END OF THE TAF PERIOD FROM GRB TO ISW SOUTHWARD.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING FROM 3 PM MONDAY TO 6 AM CST TUESDAY FOR
WIZ030-031-035>040-045-048>050.
WINTER STORM WARNING FROM 6 PM MONDAY TO 9 AM CST TUESDAY FOR
WIZ005-010>013-018>022-073-074.
&&
$$
SHORT TERM.....MPC
LONG TERM......ML
AVIATION.......ESB
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
345 PM CST SAT DEC 26 2015
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 345 PM CST SAT DEC 26 2015
AT 3 PM...A NORTHERN STREAM SHORT WAVE WAS MOVING THROUGH NORTHERN
MINNESOTA. AHEAD OF THIS WAVE...THERE IS WEAK 290K ISENTROPIC LIFT
AND OMEGA UP TO 850 MB. WITH NO ICE CRYSTAL SEEDING FROM ALOFT...
THIS WILL KEEP AREAS OF DRIZZLE OR FREEZING DRIZZLE CONTINUING
THROUGH 27.03Z. THE FREEZING DRIZZLE WILL BE MAINLY NORTH OF A
INTERSTATE 90. WITH ROAD TEMPERATURE RANGING FROM 33 TO 35F AND
APPLIED ROAD TREATMENTS...NOT ANTICIPATING TOO MANY ISSUES FOR
THOSE TRAVELING...THUS...NOT PLANNING ON ISSUING ANOTHER WINTER
WEATHER ADVISORY.
FOR TONIGHT AND SUNDAY...A CANADIAN HIGH WILL BUILD INTO THE
REGION. THIS WILL KEEP THE AREA DRY. WITH INCREASED SUBSIDENCE AND
DRY AIR ADVECTING INTO THE REGION...EXPECT SOME CLEARING TO OCCUR
ACROSS THE AREA LATE SUNDAY MORNING AND AFTERNOON. WITH SOME
SUNSHINE...TEMPERATURES WILL RANGE FROM THE MID 20S TO MID 30S.
THIS IS A COUPLE OF DEGREES ABOVE NORMAL.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 345 PM CST SAT DEC 26 2015
FROM MONDAY INTO MONDAY NIGHT...THE 26.12Z AND 26.18Z MODELS ARE
IN GOOD AGREEMENT THAT A CLOSED LOW WILL LIFT NORTH NORTHEAST FROM
MISSOURI INTO NORTHERN WISCONSIN AND UPPER MICHIGAN. WHILE IT IS
MOVING THROUGH THE UPPER MISSISSIPPI RIVER VALLEY...IT WILL BE
GRADUALLY FILLING. THIS WILL LIMIT THE WINDS AHEAD OF THE SYSTEM
TO 15 TO 25 MPH...AND FROM 10 TO 15 MPH ON TUESDAY. AS WITH THE
PREVIOUS COUPLE OF DAYS...THE MODELS CONTINUE TO STRUGGLE ON HOW
MUCH WARM AIR WILL ADVECT NORTHWARD AHEAD OF THE UPPER LEVEL LOW
ON MONDAY. THE NAM CONTINUES TO BRING THE WARMEST AIR ALOFT INTO
THE REGION. IF THIS SOLUTION VERIFIED...NORTHEAST IOWA AND
WESTERN WISCONSIN WOULD SEE A MIX OF RAIN...FREEZING RAIN...AND
SLEET FROM MONDAY MORNING THROUGH MID AFTERNOON...AND THEN IT
WOULD TRANSITION TO SNOW LATE MONDAY AFTERNOON AND CONTINUE INTO
MONDAY NIGHT. THE GFS CONTINUES TO BE THE COLDEST AND THE
PRECIPITATION WOULD BE SNOW FROM MONDAY INTO MONDAY NIGHT. SNOW
TOTALS WOULD RANGE FROM 4 TO 10 INCHES. MEANWHILE THE ECMWF WAS A
GOOD COMPROMISE BETWEEN THESE 2 SOLUTIONS AND IT WAS USED TO HELP
DELINEATE WHERE THERE WOULD BE THE BEST CHANCE OF A WINTRY MIX
WOULD OCCUR. IN THIS SCENARIO...IT WOULD OCCUR ACROSS THE EASTERN
PORTIONS OF NORTHEAST IOWA AND IN SOUTHWEST WISCONSIN. FREEZING
RAIN COULD ACCUMULATE UP TO A TENTH OF AN INCH OF ICE ACROSS
FAYETTE AND CLAYTON COUNTIES IN NORTHEAST IOWA AND GRANT COUNTY IN
SOUTHWEST WISCONSIN. SNOW TOTALS WOULD RANGE FROM 4 TO 8 INCHES.
AT THIS TIME THE HIGHEST TOTALS LOOK TO BE NORTH OF INTERSTATE 90.
WITH THE COLD AIR OVER THE CENTRAL AND NORTHERN PLAINS...THINKING
THAT IF THERE WAS ANY SHIFT TO OCCUR TO THIS LOW TRACK...IT WOULD
BE MORE LIKELY TO BE A BIT FURTHER NORTHWEST. JUST A SHIFT OF 100
MILES IN THIS DIRECTION WOULD RESULT IN MORE RAIN/FREEZING RAIN IN
SOUTHWEST WISCONSIN AND NORTHEAST IOWA...AND MORE OF A MIX FOR THE
REMAINDER OF THE AREA.
ON WEDENESDAY...ANOTHER COLD FRONT WILL MOVE THROUGH THE REGION.
WITH THIS SYSTEM HAVING MORE CONTINENTAL POLAR AIR MASS THAN THE
MARITIME POLAR AIR MASS THAT WE HAVE BECOME ACCUSTOMED TO THIS
WINTER...ONE OF THE COLDEST AIR MASSES OF THE 2015-16 WINTER WILL
MOVE INTO THE REGION. HIGHS ON NEW YEARS EVE AND DAY MAY NOT EVEN
REACH 20 DEGREES. EVEN THOUGH THE AIR MASS WILL WARM INTO THE
WEEKEND...TEMPERATURES WILL REMAIN NEAR TO SLIGHTLY BELOW NORMAL.
THIS CHANGE IN THE UPPER AIR FLOW IS DUE TO A STRONG COHERENT
MADDEN JULIAN OSCILLATION DISRUPTING THE STRONG EL NINO. THIS WILL
LIKELY LAST INTO THE FIRST WEEK OF THE NEW YEAR...AND THEN THE
STRONG EL NINO WILL ONCE AGAIN TAKE OVER AGAIN WITH TEMPERATURES
RETURN TO WARMER THAN NORMAL FOR MUCH OF JANUARY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1129 AM CST SAT DEC 26 2015
THE MAIN BAND OF PRECIPITATION IS JUST ABOUT TO THE MISSISSIPPI
RIVER AND EXPECT IT TO BE PAST KLSE BY 19Z. AFTER THAT...THE
26.15Z RAP AND THE 26.16Z RUNS OF THE HRRR AND CR-HRRR SUGGEST ANY
PRECIPITATION THROUGH THE AFTERNOON WILL BE LIGHT WITH THE
POSSIBILITY OF SOME LIGHT SNOW TO ROTATE THROUGH KRST WITH ALL THE
PRECIPITATION ENDING BY 00Z. PRIMARILY EXPECTING MVFR CEILINGS
THIS AFTERNOON INTO THE OVERNIGHT HOURS...BUT CANNOT RULE OUT SOME
IFR AT KRST IF THE LIGHT SNOW DOES GET IN THERE. SUBSIDENCE AND
DRYING BEHIND THE SHORT WAVE TROUGH WILL START TO MOVE IN LATE
TONIGHT INTO SUNDAY MORNING AND WILL BE ENOUGH TO BREAK UP THE
CLOUDS...BUT THE QUESTION BECOMES WHEN. THE 26.12Z NAM SUGGESTS
THIS COULD HAPPEN BEFORE 12Z...BUT THIS LOOKS RATHER AGGRESSIVE
AND WENT WITH THE TIMING SHOWN BY THE 26.09Z SREF MEAN BUFKIT
SOUNDINGS FOR THE MIDDLE OF SUNDAY MORNING.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...WINTER STORM WATCH FROM MONDAY MORNING THROUGH LATE MONDAY NIGHT
FOR WIZ054-055-061.
WINTER STORM WATCH FROM MONDAY AFTERNOON THROUGH LATE MONDAY
NIGHT FOR WIZ017-029-032>034-041>044-053.
MN...WINTER STORM WATCH FROM MONDAY AFTERNOON THROUGH LATE MONDAY
NIGHT FOR MNZ079-086>088-094>096.
IA...WINTER STORM WATCH FROM MONDAY MORNING THROUGH LATE MONDAY NIGHT
FOR IAZ008>011-018-019-029-030.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...04
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE
.SHORT TERM...TONIGHT AND SUNDAY
ISSUED AT 231 PM CST SAT DEC 26 2015
THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A WARM
FRONT POSITIONED OVER THE MID-MISSISSIPPI VALLEY AND AN ARCTIC COLD
FRONT DRAPED ACROSS THE UPPER PENINSULA INTO CENTRAL MINNESOTA.
NORTHERN WISCONSIN LIES BETWEEN THESE TWO FEATURES IN A REGION OF
CONFLUENT MID-LEVEL FLOW. ALTHOUGH A MORE PERSISTENT BAND OF SNOW
EXISTS ALONG THE COLD FRONT NORTHWEST OF THE REGION...AREAS OF LIGHT
WINTRY PRECIP ARE PASSING OVER NORTH-CENTRAL AND NORTHEAST WISCONSIN
EARLY THIS AFTERNOON. SO FAR...NO REPORTS OF SLIPPERY ROADS WHERE
TEMPERATURES ARE BELOW FREEZING...GENERALLY NORTH OF A LINE FROM
MARSHFIELD TO IRON MOUNTAIN. THERE WERE SOME ISOLATED REPORTS OF
LIGHT ICING OVER SOUTHWEST WISCONSIN FROM EARLIER TODAY...SO NO
PLANS TO CHANGE HEADLINES AT THIS POINT. PRECIPITATION IS SHOWERY
IN NATURE...WHICH IS HAMPERING SNOWFALL ACCUMULATIONS ACROSS THE FAR
NORTH. SOME SLEET IS ALSO MIXING IN WITH THE LIGHT RAIN OVER
CENTRAL WISCONSIN. AS THE WINTRY PRECIP CONTINUES INTO
TONIGHT...PRECIP TRENDS AND IMPACTS REMAIN THE MAIN FORECAST
CONCERNS.
TONIGHT...A WEAK 850MB LOW WILL TRAVERSE THE REGION THROUGH EARLY
THIS EVENING. MID-LEVEL FGEN AHEAD OF THE LOW AND ALONG THE
TRAILING COLD FRONT...COMBINED WITH UPPER DIVERGENCE IN THE REAR
RIGHT QUAD OF A JET STREAK...WILL CONTINUE TO GENERATE LIGHT PRECIP
THROUGH THE LATE EVENING OR EARLY OVERNIGHT HOURS. PROGGED
SOUNDINGS CONTINUE TO INDICATE THAT TEMPERATURES ALOFT STRUGGLE TO
SATURATE ABOVE THE -10C ISOTHERM THIS EVENING. SO A WINTRY MIX OF
FREEZING DRIZZLE AND LIGHT SNOW REMAINS POSSIBLE NORTH OF A
MARSHFIELD TO IRON MOUNTAIN LINE. IMPACTS ARE TOUGH TO GAUGE...BUT
DID CUT DOWN SNOW ACCUMS TO 1-2 INCHES FOR THE FAR NORTH TONIGHT
GIVEN THE SHOWERY NATURE OF THE PRECIP. SOME LIGHT ICING COULD STILL
OCCUR THOUGH...ESPECIALLY WHEN TEMPERATURES FALL TONIGHT. PLENTY OF
OBS UPSTREAM OVER IOWA AND SOUTHERN MINNESOTA ALSO INDICATE POSSIBLE
DRIZZLE...WHICH WILL BE MOVING THROUGH DURING THE EVENING. THE
ENDING TIME OF THE ADVISORY LOOKS ABOUT RIGHT...DEPENDING UPON IF
ANY ICING CONDITIONS MATERIALIZES. ONCE THE PRECIP PULLS
OUT...COLDER AIR WILL FILTER IN FROM THE NORTHWEST. LIGHT LAKE
EFFECT SNOW SHOWERS WILL IMPACT VILAS COUNTY WITHOUT MUCH
ACCUMULATIONS. BUT LOW INVERSION HEIGHTS SHOULD BRING IN CLOUDS OFF
LAKE SUPERIOR TO REINFORCE THE CLOUDY CONDITIONS. LOWS IN THE MID
20S NORTH TO LOW 30S SOUTH.
SUNDAY...DRIER ARCTIC AIR WILL GRADUALLY SHIFT SOUTHEAST ACROSS THE
STATE...ORIGINATING FROM A 1040MB HIGH OVER THE NORTHERN PLAINS.
LIGHT SNOW SHOWERS AND FLURRIES WILL LIKELY IMPACT VILAS COUNTY
THROUGH THE DAY WITHOUT MUCH ACCUMULATIONS. OTHERWISE...EXPECTING A
RATHER CLOUDY START TO THE DAY...BUT BREAKS IN THE CLOUDS SHOULD
ONLY INCREASE THROUGH THE AFTERNOON. TEMPS WILL REMAIN RELATIVELY
STEADY ACROSS THE NORTH...AND ONLY WARM INTO THE MID 30S SOUTH.
.LONG TERM...SUNDAY NIGHT THROUGH NEXT SATURDAY
ISSUED AT 231 PM CST SAT DEC 26 2015
A LOW PRESSURE SYSTEM WILL HOOK NORTH-NORTHEAST FROM SOUTHERN
TEXAS ON SUNDAY AND BE CENTERED OVER WISCONSIN BY EARLY TUESDAY.
THE POSITION OF THE "TEXAS SLINGER" TRACK WILL SIGNIFICANTLY
INFLUENCE PRECIPITATION TYPE...AND MODELS VARY ENOUGH ON THE TRACK
AND TIMING OF THIS SYSTEM TO REDUCE CONFIDENCE IN ISSUING A WINTER
STORM WATCH. HIGH PRESSURE RIDGING IN PLACE OVER THE NORTHERN
MIDWEST AHEAD OF THE APPROACHING LOW SHOULD HELP SQUEEZE THE
PRESSUE GRADIENT ACROSS OUR AREA AS THE LOW APPROACHES AND
HEIGHTENS EXPECTATIONS FOR GUSTY WINDS IN THE WISCONSIN MONDAY
NIGHT.
A SECOND SYSTEM IS EXPECTED TO AFFECT THE AREA LATE TUESDAY NIGHT
THROUGH WEDNESDAY EVENING...BRINGING A CHANCE OF LIGHT SNOW TO
THE REGION. TEMPERATURES WILL START OUT ABOVE NORMAL...BUT RETURN
CLOSER AND PERHAPS A FEW DEGREES BELOW NORMAL BY THE END OF NEXT
WEEK.
&&
.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1137 AM CST SAT DEC 26 2015
A WEAK STORM SYSTEM WILL MOVE ACROSS THE AREA THROUGH
THE EVENING. TEMPERATURES REMAIN BELOW FREEZING FROM MARSHFIELD AND
STEVENS POINT TO IRON MOUNTAIN LATE THIS MORNING. AS PRECIPITATION
SPREADS ACROSS THE AREA THIS AFTERNOON...SNOW AND FREEZING DRIZZLE
WILL IMPACT AREAS NORTH OF THIS LINE. LIGHT ICING IS POSSIBLE HERE.
TO THE SOUTH...MAINLY RAIN/DRIZZLE IS EXPECTED. PRECIPITATION WILL
PULL OUT LATE THIS EVENING. BUT NORTH FLOW OFF LAKE SUPERIOR AND
LOW INVERSION HEIGHTS WILL SUPPORT IFR/MVFR BROKEN CIGS THROUGH
MIDDAY SUNDAY.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 9 PM CST THIS EVENING FOR WIZ010-
011-018-019-030.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR WIZ005.
&&
$$
SHORT TERM.....MPC
LONG TERM......ML
AVIATION.......MPC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
220 PM CST SAT DEC 26 2015
.UPDATE...
ISSUED AT 220 PM CST SAT DEC 26 2015
THE REMAINING AREAS OF THE LIGHT SNOW AND FREEZING RAIN HAVE MOVED
EAST OF THE AREA. THERE COULD STILL BE A LITTLE BIT OF LIGHT
FREEZING DRIZZLE AT TIMES THROUGH THE AFTERNOON AS THERE IS STILL
SOME WEAK FRONTOGENESIS IN THE 850-700 MB LAYER...BUT THIS NOT
EXPECTED TO BE ENOUGH TO CAUSE ANY PROBLEMS.
UPDATE ISSUED AT 1237 PM CST SAT DEC 26 2015
THE MAIN BAND OF LIGHT SNOW AND FREEZING RAIN HAS BECOME CONFINED
FROM NORTHERN LA CROSSE AND MONROE COUNTIES NORTHWARD INTO TAYLOR
COUNTY. THERE HAS BEEN JUST ENOUGH FREEZING RAIN TO CREATE A LIGHT
COATING OF ICE ON UNTREATED SURFACES SO WILL CONTINUE THE ADVISORY
UNTIL AT LEAST THE MIDDLE OF THE AFTERNOON UNTIL THIS
PRECIPITATION MOVES OFF TO THE EAST. FARTHER TO THE WEST...NOT
MUCH GOING ON AT THIS POINT. THE 26.12Z NAM DOES SHOW A BIT OF
FRONTOGENESIS CONTINUING IN THE 850-700 MB LAYER WHICH IS HELPING
TO PRODUCE THE LIGHT SNOW ACROSS CENTRAL MINNESOTA. THE 26.16Z
HRRR SUGGESTS THERE IS A POSSIBILITY OF SOME OF THIS LIGHT SNOW
GETTING INTO SOUTHEAST MINNESOTA...SO HAVE LEFT SOME HIGHER
PRECIPITATION CHANCES IN THAT AREA...BUT NOT EXPECTING IT TO BE
ENOUGH TO CAUSE ANY PROBLEMS AND HAVE DROPPED THE ADVISORY FOR
SOUTHEAST MINNESOTA AND NORTHEAST IOWA.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 240 AM CST SAT DEC 26 2015
UPPER LEVEL SHORTWAVE TROUGH WAS LIFTING NORTHEAST INTO THE CENTRAL
PLAINS...PER LATEST WATER VAPOR IMAGERY...HELPING POWER AN AREA
OF SNOW AND RAIN ACROSS SOUTHWEST MN/WESTERN IA INTO THE PLAINS.
STRONG ISENTROPIC UPGLIDE WAS ALSO HAVING A HAND IN PRECIPITATION
PRODUCTION...WHICH WILL SLIDE ACROSS AND NORTHEAST OF THE AREA BY
00Z THIS EVENING. SOME FRONTOGENETIC BANDING...MORE NORTH...AS
WILL BE THE UPPER LEVEL JET DYNAMICS. SO LOCALLY...MUCH OF THE
PRECIPITATION WILL BE TIED TO THE LOW LEVEL WARMING. WHAT TYPE
WILL FALL WILL BE BASED ON WHETHER ICE IS AVAILABLE IN THE CLOUD
AND WHAT THE TEMP PROFILE LOOKS LIKE. MOSTLY...ITS A QUESTION OF
ICE.
TIME/HEIGHT X-SECTIONS AND BUFKIT SOUNDINGS SUGGEST ICE IS GOING TO
BE HARD TO COME BY FOR A BULK OF THE LOCAL FORECAST AREA...MAKING
DRIZZLE/RAIN...OR FREEZING DEPENDING ON SFC TEMPS...THE
PRECIPITATION TYPE. THE FARTHER WEST/NORTH YOU GO THE MORE LIKELY
THE CLOUD WILL BE DEEP ENOUGH FOR ICE...WITH SNOW THEN MOST
LIKELY. LIGHT ICING COULD OCCUR ON UNTREATED ROAD AND SIDEWALKS.
SNOW ACCUMULATIONS LOOK MINIMAL...WITH MOST IN NORTH-CENTRAL WI.
OVERALL...THE GREATER THREAT WILL BE THE POTENTIAL FOR ICING. WILL
CONTINUE THE WINTER WEATHER ADV AS IS FOR NOW.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 240 AM CST SAT DEC 26 2015
WELL...THE CONSISTENCY OF THE ECMWF MAY BE WINNING OUT FOR A STORM
SYSTEM SLATED TO IMPACT PARTS OF THE REGION MONDAY-MONDAY NIGHT. THE
PREVIOUS QUICK/MORE EAST GFS AND GEM HAVE NOW TRENDED TOWARD THE
FARTHER WEST SOLUTION OF THE EC...LENDING GREATER CONFIDENCE TO A
SWATH OF PRECIPITATION FOR MON/MON NIGHT.
CLOSED UPPER LOW WILL LIFT OUT OF TX SUNDAY NIGHT...DRIVING UP INTO
THE EASTERN GREAT LAKES MONDAY NIGHT. WHILE COMING CLOSER
TOGETHER...STILL SOME VARIANCES WITH THE SYSTEM/S SFC LOW
PLACEMENT...WITH THE EC OVER CENTRAL IA BY 06Z TUE AND THE GFS OVER
NORTHERN ILL AT THAT TIME. WEST-EAST ORIENTATED SLOPING
FRONTOGENETIC LIFT WITH STRONG LOW LEVEL THERMODYNAMICS LEADING THE
UPPER LEVEL LOW INTO THE REGION...AND THE LEFT EXIT REGION OF A 100+
KT UPPER LEVEL JET ENHANCING THE LIFT. UNLIKE THE RECENT
PRECIPITATION EVENTS WHERE ICE IN THE CLOUD HAS BEEN
QUESTIONABLE...SATURATION IS MUCH DEEPER AND THERE IS A FETCH OF
GULF MOISTURE TO PLAY WITH. WHAT IS A CONCERN IS THE AMOUNT OF LOW
LEVEL WARMING. THE NAM BRINGS A NOSE OF 800-850 MB WARM AIR
UPWARDS OF 7 C ACROSS PARTS OF THE AREA. THE GFS IS NOT AS A
ROBUST...ALTHOUGH ITS 00Z SOLUTION IS NOW TRENDING A BIT WARMER IN
THAT LAYER THAN ITS PREVIOUS RUNS. WITH COLD AIR IN PLACE AT THE
SFC BY THIS TIME...FREEZING RAIN/SLEET ENTER THE PICTURE...WITH
THE POTENTIAL FOR IMPACTFUL AMOUNTS. SEVERAL INCHES OF SNOW
ACCUMULATION ALSO LIKELY. AGAIN THOUGH - MUCH OF WHAT FALLS AND
WHERE IS GOING TO HINGE ON JUST HOW WARM THIS WARM LAYER
IS...COUPLED WITH THE POSITIONING OF THE SFC LOW. DIFFICULT
QUESTIONS TO ANSWER AT THIS TIME...BUT ITS A STORM SYSTEM THAT
WILL HAVE IMPACTS TO TRAVEL. IN ADDITION...IF ITS ENDS UP BEING
MORE FREEZING RAIN...WINDS LOOK STRONG AND GUSTY MONDAY. ICE
ACCUMULATIONS ON TREES AND POWERLINES WOULD OCCUR...AND WITH THOSE
WINDS...DAMAGE TO LIMBS/POWER LINES WOULD BE HIGHLY LIKELY. A
SCENARIO THAT BEARS A VERY CLOSE WATCH. WILL TAKE A MIDDLE OF THE
ROAD/CONSENSUS APPROACH TO PRECIPITATION CHANCES AND PRECIPITATION
TYPES FOR NOW. THINK A WINTER STORM WATCH WILL EVENTUALLY BE
NEEDED FOR A PORTION OF THE AREA IF CURRENT MODEL SOLUTIONS
PERSIST.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1129 AM CST SAT DEC 26 2015
THE MAIN BAND OF PRECIPITATION IS JUST ABOUT TO THE MISSISSIPPI
RIVER AND EXPECT IT TO BE PAST KLSE BY 19Z. AFTER THAT...THE
26.15Z RAP AND THE 26.16Z RUNS OF THE HRRR AND CR-HRRR SUGGEST ANY
PRECIPITATION THROUGH THE AFTERNOON WILL BE LIGHT WITH THE
POSSIBILITY OF SOME LIGHT SNOW TO ROTATE THROUGH KRST WITH ALL THE
PRECIPITATION ENDING BY 00Z. PRIMARILY EXPECTING MVFR CEILINGS
THIS AFTERNOON INTO THE OVERNIGHT HOURS...BUT CANNOT RULE OUT SOME
IFR AT KRST IF THE LIGHT SNOW DOES GET IN THERE. SUBSIDENCE AND
DRYING BEHIND THE SHORT WAVE TROUGH WILL START TO MOVE IN LATE
TONIGHT INTO SUNDAY MORNING AND WILL BE ENOUGH TO BREAK UP THE
CLOUDS...BUT THE QUESTION BECOMES WHEN. THE 26.12Z NAM SUGGESTS
THIS COULD HAPPEN BEFORE 12Z...BUT THIS LOOKS RATHER AGGRESSIVE
AND WENT WITH THE TIMING SHOWN BY THE 26.09Z SREF MEAN BUFKIT
SOUNDINGS FOR THE MIDDLE OF SUNDAY MORNING.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...04
SHORT TERM...RIECK
LONG TERM....RIECK
AVIATION...04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1237 PM CST SAT DEC 26 2015
.UPDATE...
ISSUED AT 1237 PM CST SAT DEC 26 2015
THE MAIN BAND OF LIGHT SNOW AND FREEZING RAIN HAS BECOME CONFINED
FROM NORTHERN LA CROSSE AND MONROE COUNTIES NORTHWARD INTO TAYLOR
COUNTY. THERE HAS BEEN JUST ENOUGH FREEZING RAIN TO CREATE A LIGHT
COATING OF ICE ON UNTREATED SURFACES SO WILL CONTINUE THE ADVISORY
UNTIL AT LEAST THE MIDDLE OF THE AFTERNOON UNTIL THIS
PRECIPITATION MOVES OFF TO THE EAST. FARTHER TO THE WEST...NOT
MUCH GOING ON AT THIS POINT. THE 26.12Z NAM DOES SHOW A BIT OF
FRONTOGENESIS CONTINUING IN THE 850-700 MB LAYER WHICH IS HELPING
TO PRODUCE THE LIGHT SNOW ACROSS CENTRAL MINNESOTA. THE 26.16Z
HRRR SUGGESTS THERE IS A POSSIBILITY OF SOME OF THIS LIGHT SNOW
GETTING INTO SOUTHEAST MINNESOTA...SO HAVE LEFT SOME HIGHER
PRECIPITATION CHANCES IN THAT AREA...BUT NOT EXPECTING IT TO BE
ENOUGH TO CAUSE ANY PROBLEMS AND HAVE DROPPED THE ADVISORY FOR
SOUTHEAST MINNESOTA AND NORTHEAST IOWA.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 240 AM CST SAT DEC 26 2015
UPPER LEVEL SHORTWAVE TROUGH WAS LIFTING NORTHEAST INTO THE CENTRAL
PLAINS...PER LATEST WATER VAPOR IMAGERY...HELPING POWER AN AREA
OF SNOW AND RAIN ACROSS SOUTHWEST MN/WESTERN IA INTO THE PLAINS.
STRONG ISENTROPIC UPGLIDE WAS ALSO HAVING A HAND IN PRECIPITATION
PRODUCTION...WHICH WILL SLIDE ACROSS AND NORTHEAST OF THE AREA BY
00Z THIS EVENING. SOME FRONTOGENETIC BANDING...MORE NORTH...AS
WILL BE THE UPPER LEVEL JET DYNAMICS. SO LOCALLY...MUCH OF THE
PRECIPITATION WILL BE TIED TO THE LOW LEVEL WARMING. WHAT TYPE
WILL FALL WILL BE BASED ON WHETHER ICE IS AVAILABLE IN THE CLOUD
AND WHAT THE TEMP PROFILE LOOKS LIKE. MOSTLY...ITS A QUESTION OF
ICE.
TIME/HEIGHT X-SECTIONS AND BUFKIT SOUNDINGS SUGGEST ICE IS GOING TO
BE HARD TO COME BY FOR A BULK OF THE LOCAL FORECAST AREA...MAKING
DRIZZLE/RAIN...OR FREEZING DEPENDING ON SFC TEMPS...THE
PRECIPITATION TYPE. THE FARTHER WEST/NORTH YOU GO THE MORE LIKELY
THE CLOUD WILL BE DEEP ENOUGH FOR ICE...WITH SNOW THEN MOST
LIKELY. LIGHT ICING COULD OCCUR ON UNTREATED ROAD AND SIDEWALKS.
SNOW ACCUMULATIONS LOOK MINIMAL...WITH MOST IN NORTH-CENTRAL WI.
OVERALL...THE GREATER THREAT WILL BE THE POTENTIAL FOR ICING. WILL
CONTINUE THE WINTER WEATHER ADV AS IS FOR NOW.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 240 AM CST SAT DEC 26 2015
WELL...THE CONSISTENCY OF THE ECMWF MAY BE WINNING OUT FOR A STORM
SYSTEM SLATED TO IMPACT PARTS OF THE REGION MONDAY-MONDAY NIGHT. THE
PREVIOUS QUICK/MORE EAST GFS AND GEM HAVE NOW TRENDED TOWARD THE
FARTHER WEST SOLUTION OF THE EC...LENDING GREATER CONFIDENCE TO A
SWATH OF PRECIPITATION FOR MON/MON NIGHT.
CLOSED UPPER LOW WILL LIFT OUT OF TX SUNDAY NIGHT...DRIVING UP INTO
THE EASTERN GREAT LAKES MONDAY NIGHT. WHILE COMING CLOSER
TOGETHER...STILL SOME VARIANCES WITH THE SYSTEM/S SFC LOW
PLACEMENT...WITH THE EC OVER CENTRAL IA BY 06Z TUE AND THE GFS OVER
NORTHERN ILL AT THAT TIME. WEST-EAST ORIENTATED SLOPING
FRONTOGENETIC LIFT WITH STRONG LOW LEVEL THERMODYNAMICS LEADING THE
UPPER LEVEL LOW INTO THE REGION...AND THE LEFT EXIT REGION OF A 100+
KT UPPER LEVEL JET ENHANCING THE LIFT. UNLIKE THE RECENT
PRECIPITATION EVENTS WHERE ICE IN THE CLOUD HAS BEEN
QUESTIONABLE...SATURATION IS MUCH DEEPER AND THERE IS A FETCH OF
GULF MOISTURE TO PLAY WITH. WHAT IS A CONCERN IS THE AMOUNT OF LOW
LEVEL WARMING. THE NAM BRINGS A NOSE OF 800-850 MB WARM AIR
UPWARDS OF 7 C ACROSS PARTS OF THE AREA. THE GFS IS NOT AS A
ROBUST...ALTHOUGH ITS 00Z SOLUTION IS NOW TRENDING A BIT WARMER IN
THAT LAYER THAN ITS PREVIOUS RUNS. WITH COLD AIR IN PLACE AT THE
SFC BY THIS TIME...FREEZING RAIN/SLEET ENTER THE PICTURE...WITH
THE POTENTIAL FOR IMPACTFUL AMOUNTS. SEVERAL INCHES OF SNOW
ACCUMULATION ALSO LIKELY. AGAIN THOUGH - MUCH OF WHAT FALLS AND
WHERE IS GOING TO HINGE ON JUST HOW WARM THIS WARM LAYER
IS...COUPLED WITH THE POSITIONING OF THE SFC LOW. DIFFICULT
QUESTIONS TO ANSWER AT THIS TIME...BUT ITS A STORM SYSTEM THAT
WILL HAVE IMPACTS TO TRAVEL. IN ADDITION...IF ITS ENDS UP BEING
MORE FREEZING RAIN...WINDS LOOK STRONG AND GUSTY MONDAY. ICE
ACCUMULATIONS ON TREES AND POWERLINES WOULD OCCUR...AND WITH THOSE
WINDS...DAMAGE TO LIMBS/POWER LINES WOULD BE HIGHLY LIKELY. A
SCENARIO THAT BEARS A VERY CLOSE WATCH. WILL TAKE A MIDDLE OF THE
ROAD/CONSENSUS APPROACH TO PRECIPITATION CHANCES AND PRECIPITATION
TYPES FOR NOW. THINK A WINTER STORM WATCH WILL EVENTUALLY BE
NEEDED FOR A PORTION OF THE AREA IF CURRENT MODEL SOLUTIONS
PERSIST.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1129 AM CST SAT DEC 26 2015
THE MAIN BAND OF PRECIPITATION IS JUST ABOUT TO THE MISSISSIPPI
RIVER AND EXPECT IT TO BE PAST KLSE BY 19Z. AFTER THAT...THE
26.15Z RAP AND THE 26.16Z RUNS OF THE HRRR AND CR-HRRR SUGGEST ANY
PRECIPITATION THROUGH THE AFTERNOON WILL BE LIGHT WITH THE
POSSIBILITY OF SOME LIGHT SNOW TO ROTATE THROUGH KRST WITH ALL THE
PRECIPITATION ENDING BY 00Z. PRIMARILY EXPECTING MVFR CEILINGS
THIS AFTERNOON INTO THE OVERNIGHT HOURS...BUT CANNOT RULE OUT SOME
IFR AT KRST IF THE LIGHT SNOW DOES GET IN THERE. SUBSIDENCE AND
DRYING BEHIND THE SHORT WAVE TROUGH WILL START TO MOVE IN LATE
TONIGHT INTO SUNDAY MORNING AND WILL BE ENOUGH TO BREAK UP THE
CLOUDS...BUT THE QUESTION BECOMES WHEN. THE 26.12Z NAM SUGGESTS
THIS COULD HAPPEN BEFORE 12Z...BUT THIS LOOKS RATHER AGGRESSIVE
AND WENT WITH THE TIMING SHOWN BY THE 26.09Z SREF MEAN BUFKIT
SOUNDINGS FOR THE MIDDLE OF SUNDAY MORNING.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR WIZ017-
029-033-034-041.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...04
SHORT TERM...RIECK
LONG TERM....RIECK
AVIATION...04
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
450 AM EST MON DEC 28 2015
.DISCUSSION...
...WARM WEATHER TO CONTINUE MOST OF THE WORK WEEK...
...LINGERING SWELL TO KEEP RIP CURRENT THREAT ELEVATED...
TODAY-TONIGHT...LITTLE CHANGE TO THE WARM/HUMID WX PATTERN THAT
HAS DOMINATED THE REGION FOR THE PAST SEVERAL DAYS. RAP ANALYSIS
SHOWS THE DEEP LYR RIDGE EXTENDING JUST S OF BERMUDA TO THE
YUCATAN CHANNEL MAINTAINING ITS GRIP...THOUGH A DVLPG STORM SYSTEM
OVER THE ARKLATEX HAS MANAGED TO ERODE THE WRN FLANK OF THE RIDGE
AND PUSH A COLD FRONT INTO THE WRN GOMEX. WHILE THE SYSTEM HAS
GOOD UPR LVL SUPPORT FROM AN 80-100KT JET STREAK IN THE H30-H20
LYR...THE STREAK HAS ALREADY ROUNDED THE BASE OF THE TROF AND
OBTAINED A LIFTING ORIENTATION THAT NOT ALLOW IT TO UNDERCUT THE
ATLC RIDGE AXIS.
WHILE THE WRN FLANK OF THE RIDGE WILL INITIALLY ERODE AS THE STORM
SYSTEM LIFTS ACRS THE MID SOUTH...ULTIMATELY IT WILL HAVE LITTLE
DIFFICULTY IN BLOCKING OUT ITS ASSOCD COLD FRONT SYSTEM FROM CENTRAL
FL. STEADY S/SE FLOW THRU THE H100-H50 LYR WILL GRADUALLY SHIFT TO
THE S/SW AS THE FRONT PUSHES INTO THE ERN GOMEX...MAINTAINING THE
STRONG WARM AIR ADVECTION PATTERN THAT HAS GRIPPED THE FL PENINSULA
FOR THE PAST WEEK. RECORD AFTN MAX TEMPS PSBL AT DAB/MCO/VRB...MLB
LOOKS SAFE. RECORD OVERNIGHT WARM MIN TEMPS HAVE A REASONABLE SHOT
OF FALLING AT ALL FOUR SITES.
RELATIVELY DRY/STABLE POCKET OF AIR OVER THE FL PENINSULA WILL BE
ERODED BY DEEPER MOISTURE THAT THE SRLY FLOW WILL PULL IN FROM THE
FL STRAITS/NW CARIB/SE GOMEX. IN ADDITION...RAP ANALYSIS INDICATED A
LCL POCKET OF ENHANCED H85-H30 VORTICITY CENTERED JUST N OF LAKE
OKEECHOBEE THAT THE GLOBAL MODELS ARE NOT RESOLVING. THERMODYANMIC
INSTABLITIY IS A MIXED BAG AT BEST...H85-H70 LAPSE RATES ARE A
RESPECTABLE 6.5-7.0C/KM ARND THE LAKE THANKS TO A COOL POCKET OF H70
TEMPS BTWN 5C-7C...BUT DECREASE TO 5.0-5.5C/KM N OF I-4. H50 TEMPS
BTWN -5C/-6C ARE UNIMPRESSIVE...ASSOCD H70-H50 LAPSE RATES BTWN
3.5-4.5C/KM ARE EQUALLY UNIMPRESSIVE.
RADAR TREND SHOWS LITTLE IN THE WAY OF SHRA ACTIVITY OVER THE LCL
ATLC...AND WITH STEERING WINDS VEERING TO THE S...COASTAL SHRA
ACTIVITY IS EXPECTED TO BE MINIMAL THRU DAYBREAK TUE. HOWEVER...MAX
TEMPS IN THE L/M80S COUPLED WITH THE MID LVL VORTICITY AND (ALBEIT
WEAK) MOISTURE ADVECTION SUGGESTS SLIGHTLY HIGHER PRECIP COVERAGE
THE AFTN/EVNG. STRONG THERMAL CAP ARND THE H85 LYR WILL PRECLUDE
DEEP CONVECTION...BUT CHC POPS S OF I-4 ARE REASONABLE...SLGT CHC N
OF I-4. PRECIP WILL CHOKE OFF BY MIDNIGHT WITH THE LOSS OF DIURNAL
HEATING. AFTN MAX TEMPS IN THE L/M80S (10-15F ABV AVG) AND OVERNIGHT
MINS IN THE M/U60S INTERIOR AND U60S/L70S ALONG THE COAST (15-20F
ABV AVG).
TUE-THU...CUT-OFF CYCLONE OVER THE ARKLATEX WILL EJECT RAPIDLY
NORTH TO THE GREAT LAKES TUE AS NEXT LONGWAVE TROUGH EVOLVES AND
ELONGATES FROM THE GREAT LAKES TO THE FOUR CORNERS. MEANWHILE...
THE PERSISTENT SW ATLANTIC ANTICYCLONE REMAINS IN PLACE FOR A FEW
MORE DAYS BEFORE A PATTERN CHANGE FINALLY TAKES PLACE. LOW-LEVEL
RIDGE DROPS SOUTH TO CENTRAL PENINSULA TUE/WED...THEN WEAKENS AND
SHIFTS OFFSHORE AS FRONTAL TROUGH DROPS THROUGH PANHANDLE AND INTO
NORTHERN PENINSULA THU. EARLY MORNING FOG/STRATUS LIKELY TUE AND
WED...ESPECIALLY NORTH/INTERIOR. MOISTURE/FORCING LACKING FOR
MENTIONABLE POPS TUE. APPROACHING PRE-FRONTAL MOISTURE BAND AND
INCREASING CONVERGENCE SUGGEST ISOLATED/SCATTERED SHOWERS MID
WEEK. MAX/MIN TEMPS REMAIN 15/20 DEGREES ABOVE NORMAL
TUE/WED...THEN ABOUT A CATEGORY LOWER THU DUE TO INCREASED CLOUD
COVER.
FRI-SUN...UNSETTLED PERIOD INTO AT LEAST THE FIRST HALF OF THE
WEEKEND AS MODERATE ZONAL TO WEAKLY CYCLONIC MID-UPPER FLOW
DEVELOPS WITH SOME PERIODS OF ENHANCED LIFT WITHIN PERTURBED UPPER
JET. SHALLOW FRONTAL BOUNDARY DROPS THROUGH CWA FRI WITH ONSET OF
COOLER NORTHERLY FLOW. DEEP MOISTURE BAND LIKELY TO SLOW/STALL
ACROSS PORTION OF CENTRAL/SOUTHERN PENINSULA OVER THE WEEKEND WITH
AT LEAST 30-40 PERCENT PRECIP CHANCES LINGERING. NOTICEABLE POST-
FRONTAL TEMP FALL...BUT ONLY TOWARD SEASONAL NORMALS FRI/SAT...
THEN POSSIBLY BELOW NORMAL SUNDAY...FOR THE FIRST TIME IN A LONG
WHILE.
&&
.AVIATION...THRU 29/12Z
SFC WINDS: THRU 28/15Z...E/SE 3-8KTS. BTWN 28/15Z-28/23Z...S/SE
8-13KTS WITH OCNL SFC G22KTS COASTAL SITES. BTWN 28/23Z-29/02Z...
BCMG S/SE 3-7KTS.
VSBYS/WX/CIGS: THRU 28/15Z...N OF KISM-KTIX LCL MVFR CIGS BTWN
FL010-020 LCL IFR VSBYS IN BR...S OF KISM-KTIX AREAS CIGS BTWN
FL040-060...SLGT CHC OF BRIEF MVFR SHRAS E OF KMLB-KOBE. BTWN
28/15Z-28/24Z...S OF KISM-KTIX CHC MVFR SHRAS...N OF KISM-KTIX SLGT
CHC OF MVFR SHARS. BTWN 29/00Z-29/06Z...SLGT CHC MVFR SHRAS ALL
SITES. AFT 29/06Z...N OF KISM-KTIX-KOMN AREAS PTHCY VSBYS IN BR.
&&
.MARINE...
TODAY-TONIGHT...LITTLE CHANGE TO THE WX PATTERN THAT HAS PREVAILED
OVER THE LCL ATLC FOR THE PAST SVRL DAYS. DEEP LYR RIDGE AXIS
BLANKETING THE W ATLC/ERN GOMEX REGION WILL MAINTAIN A GENTLE TO
MODERATE SERLY BREEZE OVER THE NEARSHORE LEG...MODERATE TO LOW END
FRESH BREEZE OVER THE OFFSHORE LEG. LATEST BUOY OBS INDICATE SEAS
RUNNING 3-4FT NEARSHORE AND 4-5FT OFFSHORE...LARGELY DUE TO A
DIMINISHING LONG PD 2-4FT SWELL...SFC WINDS AOB 15KTS. NO STATEMENTS
NECESSARY WITH THE MRNG FCST PACKAGE.
TUE-THU...SURFACE RIDGE DROPS SLOWLY SOUTH RESULTING IN LIGHT
SE/S FLOW TUE BECOMING S/SW WED/THU...WITH COMBINED SEAS 3-4
FEET.
FRI...FRONTAL TROUGH PROGRESSES SOUTH THROUGH THE WATERS DURING
THE DAY CAUSING LIGHT WINDS TO VEER NORTHERLY FOLLOWING PASSAGE.
SEAS RANGING FROM 2 FEET NEAR SHORE TO 4 FEET OFFSHORE...BUILDING
IN THE GULF STREAM.
&&
.CLIMATE...
DAILY HI MAX AND HI MIN TEMP RECORDS
28-DEC
DAB 83...1988 66...1942
MCO 85...1916 66...2013
MLB 87...1981 71...1990
VRB 84...1981 71...1990
29-DEC
DAB 83...1946 67...2007
MCO 84...2014 67...1990
MLB 84...2014 70...1962
VRB 85...2014 73...1990
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 81 69 83 68 / 20 20 10 10
MCO 84 67 86 68 / 20 20 10 10
MLB 82 71 84 71 / 30 20 10 10
VRB 83 72 85 70 / 30 20 10 10
LEE 84 68 85 69 / 20 20 10 10
SFB 84 67 85 68 / 20 20 10 10
ORL 84 67 84 70 / 20 20 10 10
FPR 82 72 84 71 / 30 20 10 10
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
SHORT TERM/AVIATION...BRAGAW
LONG TERM....SPRATT
AREA FORECAST DISCUSSION
National Weather Service Lincoln IL
344 AM CST MON DEC 28 2015
.SHORT TERM...(Today)
ISSUED AT 343 AM CST MON DEC 28 2015
Rain has overspread the entire forecast area early this morning.
Galesburg temperature has dropped to 32, so some freezing rain
occurring there. Sleet may be mixing with rain north of a line from
Canton to Bloomington, but no confirmation is apparent in the web-
cameras that are available. Bloomington`s observation has carried
`unknown precipitation` for several hours already this morning with
air temps down to 33, so some sleet possibly occurring there.
The 00z NAM came in with warmer surface temps than previous model
runs, but the RAP and GFS keep a colder airmass across our northern
counties through the morning, supporting the winter weather scenario
in our headline products. Even the NAM still supports some freezing
rain with a mix of sleet this morning north of Peoria. We may see
slightly less ice than a quarter inch across the winter storm
warning area, but the impacts from any amount of ice could be large
due to the strong winds blowing the trees and power lines around
with any amount of ice. We will be keeping the headlines going
without any changes this morning. Winter storm warning for freezing
rain and sleet from Peoria and north until 3 pm looks fine, with a
freezing rain advisory from Fulton to McLean counties until noon
looking ok too.
The track of the surface low from south to north up the Mississippi
River Valley supports some thunder potential in our eastern and
southern counties through the day, with locally heavy rain still
possible. It also supports a surge of warm air into our entire
forecast area this afternoon, helping to shut down any additional
wintry precipitation. Impacts from any ice accumulation could last
after surface temperatures climb above freezing, due to strong winds
affecting icy trees and power lines.
A dry slot is forecast to progress from south to north through
Illinois this afternoon, so we diminished precip chances
accordingly. Areas north of I-74 should see precip linger until
evening.
&&
.LONG TERM...(Tonight through Sunday)
ISSUED AT 343 AM CST MON DEC 28 2015
Strong surface low pressure of 997 mb over southeast OK to lift ne
into west central IL early this evening and lift across nw IL during
this evening. Low pressure will then weaken to 1002 mb as it lifts
into west central lower MI by 12Z/6 am Tue. Rain will diminish
quickly from sw to ne during this evening, with highest pops north
of I-74 early this evening, and just 20-30% chances of light
precipitation lingering overnight from I-74 northeast. Enough cold
air present to give a chance of light snow too over the IL river
valley tonight but little or no accumulations expected nw of the IL
river. Winds will drop off below wind advisory criteria by 6 pm and
become sw 15-25 mph by overnight. Went a few degrees cooler for lows
tonight ranging from near 30F far western CWA to the mid to upper
30s from I-57 east, with mildest readings near the Wabash river.
Breezy sw winds and clouds continue to linger over central IL on Tue
in wake of strong storm system pulling ne across Lake Huron, but
should be dry. Temperatures not expected to climb but a few degrees
on Tue with highs in the low to mid 30s west of I-57 and upper
30s/lower 40s east of I-57. Dry conditions continue on Tue night as
sw winds diminish. An approaching short wave from the Pacific states
to keep clouds around, with light snow chances just west of IL
overnight Tue night. Lows Tue night range from mid 20s over IL river
valley to lower 30s from I-70 southeast.
A large short wave lifts ne across IL and into lower MI during Wed
but has limited moisture over IL so will continue small chances (20-
30%) of light precipitation, mainly light snow central IL and chance
of light rain/snow in eastern/se IL. A fair amount of clouds again
on Wed with highs ranging from lower 30s over IL river valley to
around 40F in southeast IL.
Extended forecast models continue to show a large upper level trof
dominating the northeast half of the country during the 2nd half of
the week. Also large Canadian high pressure over the Rockies and
ridging into the southern plains to keep a cooler nw flow over IL
from Thu into New Years weekend. Temperatures averaging a bit below
normal for a change especially Thu/Fri when highs as cold as mid to
upper 20s in central IL and lows in the teens. Brunt of light snow
chances stays ne of central IL over the Great Lakes region late this
work week but could see more clouds linger still on Thu especially
in ne CWA, before mostly sunny skies eventually arrives Fri into the
weekend.
&&
.AVIATION...(For the 06Z TAFS through 06Z Monday night)
ISSUED AT 1107 PM CST SUN DEC 27 2015
The rain continues to make slow progress northeast across
the area with the dry low levels eroding much of the precip
over in far eastern IL. As expected, we have had some breaks
in the MVFR and IFR cigs this evening but expect all areas
to experience MVFR to LIFR cigs later tonight into Monday.
The main concern will be the transition from rain to sleet
to freezing rain at PIA and BMI late tonight thru the
morning before changing back to rain in the afternoon. The
other major impact from this storm will be with the strong
and gusty easterly winds late tonight and especially Monday
morning as the storm approaches. We expect easterly winds
of 25 to 35 kts overnight with gusts to 45 kts by morning.
We could see a period of east winds of 30 to 35 kts during
the morning as the most intense precip moves over the area.
Winds should become southeast to south by Monday afternoon
as the storm system shifts to our north with speeds gradually
to decreasing to between 15 and 20 kts by 00z.
&&
.ILX Watches/Warnings/Advisories...
Flash Flood Watch through this afternoon for ILZ044>046-049-050-
052>057-061>063-066>068-071>073.
Wind Advisory until 6 PM CST this evening for ILZ027>031-036>038-
040>057-061.
Winter Storm Warning until 3 PM CST this afternoon for
ILZ027>031.
Flash Flood Watch through this evening for ILZ051.
Freezing Rain Advisory until noon CST today for ILZ036>038.
&&
$$
SHORT TERM...Shimon
LONG TERM...07
AVIATION...Smith
AREA FORECAST DISCUSSION
National Weather Service Lincoln IL
1117 PM CST SUN DEC 27 2015
.UPDATE...
ISSUED AT 855 PM CST SUN DEC 27 2015
00z ILX sounding showing a fairly substantial dry layer from
850 mb to 700 mb this evening and some of the dry air is working
on the rain shield that was making its ways northward over the
forecast area. Rainfall rates with this initial band were quite
light but expect those to start to pick later this evening and
as the low to mid level warm advection intensifies ahead of the
deep upper low currently over central Tx. The surface low will
track right across the region Monday afternoon and evening with
the most intense rainfall (freezing rain/sleet across the north)
Monday morning. RAP forecast soundings showing surface temps
supporting mostly a rain and sleet mix north before a transition
over to freezing rain in the 08z-10z time frame in Peoria, and
between 10z and 12z in Bloomington. As the precipitation works
its way north overnight, look for the easterly winds to increase
to between 25 to 35 mph with gusts of 45 to 50 mph possible Monday
morning as the pressure gradient really tightens up.
Have made some minor adjustments to the timing of the precip based
on evening trends along with some tweaks to the temps and winds.
Otherwise, no major changes to the going forecast, winter storm
warning and freezing rain advisory. We should have the updated
ZFP out by 920 pm.
&&
.SHORT TERM...(Tonight)
ISSUED AT 526 PM CST SUN DEC 27 2015
A somewhat narrow band of moderate to heavy rain continues along
the I-70 corridor this afternoon continuing to increase the
rainfall totals in that area...now already with many locations in
the 4+ inch range for rainfall between I-70 and I-74. This band
will shift northward overnight as the warm advection region aloft
pushes north with increasing southerly flow ahead of an intense
low over Texas lifts northward toward central IL. With Canadian
high pressure moving by to the north of the Great Lakes
overnight...northerly surface flow will bring temperatures to near
freezing overnight. A wedge of warm air at the 700 to 900 mb level
(2000-1000 feet) will push above the cold surface layer...and we
should see a mix of brief snow and sleet changing over to freezing
rain from around Fulton to McLean County northward. Progressively
heavier and more widespread precipitation will spread northward
through the early morning hours Monday as the low center
approaches. A winter storm warning is in effect for
Knox...Peoria...and Woodford counties northward 3 a.m. to 3 p.m.
Monday and a freezing rain advisory is in effect Midnight to noon
Monday from Fulton to Mclean County. In addition...strong NE winds
30-35 mph and gusts to around 50 mph will develop overnight as the
intense surface pressure gradients around the low approach. Any
ice accumulation on elevated objects such as
trees...powerlines...could be enhanced by the winds. Even without
ice accumulations...the winds would be strong enough to produce
minor tree damage and toss loose objects. A wind advisory is in
effect for these areas from Midnight to 6 p.m. Monday.
.LONG TERM...(Monday through Sunday)
ISSUED AT 526 PM CST SUN DEC 27 2015
Widespread moderate to heavy precipitation rates and strong ENE
winds will continue much of the day Monday while surface
temperatures rise to gradually above freezing. I-74 as far east as
Bloomington should see the best chances for freezing rain
continuing until around noon...while to the south any freezing
rain should end by mid morning. Accumulations to around a quarter
inch I-74 northward in this area are likely...while more like a
tenth of an inch southward through Fulton...Tazewell...and Mclean
county are expected due to the shorter duration of freezing
temperatures. Farther south...only short durations of freezing
precipitation are expected although the additional 1.5 inches or
so of precipitation will exacerbate the flooding which is
prevalent south of I-72.
A northern stream weather system approaching the Pacific
Northwest will track into the Midwest by Wed morning and bring
small chances of light rain/snow showers to central IL on Wed.
Southeast IL looks drier now on Wed and wx system shifts ne of
central IL Wed night. Highs Wed to range from 30-35F nw of the IL
river to 40-45F from I-70 southeast.
Strong upper level trof dominates the northeast half of the country
during 2nd half of the week, while large Canadian high pressure
settling into the Rockies and high plains will bring an extended
period of below normal temperatures to IL for a change. The coldest
air will be over area on Thu/Fri with highs staying below freezing
for most of central/SE IL. Have partly cloudy skies Thu/Fri.
Highs will only modify slightly New Years weekend into the low to
mid 30s despite more sunshine.
&&
.AVIATION...(For the 06Z TAFS through 06Z Monday night)
ISSUED AT 1107 PM CST SUN DEC 27 2015
The rain continues to make slow progress northeast across
the area with the dry low levels eroding much of the precip
over in far eastern IL. As expected, we have had some breaks
in the MVFR and IFR cigs this evening but expect all areas
to experience MVFR to LIFR cigs later tonight into Monday.
The main concern will be the transition from rain to sleet
to freezing rain at PIA and BMI late tonight thru the
morning before changing back to rain in the afternoon. The
other major impact from this storm will be with the strong
and gusty easterly winds late tonight and especially Monday
morning as the storm approaches. We expect easterly winds
of 25 to 35 kts overnight with gusts to 45 kts by morning.
We could see a period of east winds of 30 to 35 kts during
the morning as the most intense precip moves over the area.
Winds should become southeast to south by Monday afternoon
as the storm system shifts to our north with speeds gradually
to decreasing to between 15 and 20 kts by 00z.
&&
.ILX Watches/Warnings/Advisories...
Flash Flood Watch through Monday afternoon for ILZ044>046-049-
050-052>057-061>063-066>068-071>073.
Wind Advisory until 6 PM CST Monday for ILZ027>031-036>038-
040>057-061.
Winter Storm Warning from 3 AM to 3 PM CST Monday for ILZ027>031.
Flash Flood Watch through Monday evening for ILZ051.
Freezing Rain Advisory until noon CST Monday for ILZ036>038.
&&
$$
UPDATE...Smith
SHORT TERM...Geelhart
LONG TERM...Onton
AVIATION...Smith
AREA FORECAST DISCUSSION
NWS JACKSON KY
1228 AM EST MON DEC 28 2015
.UPDATE...
ISSUED AT 1228 AM EST MON DEC 28 2015
MADE SOME LATE EVENING UPDATES TO THE FORECAST PACKAGE. SHOWERS
ARE DISSIPATING ALONG THE SFC FRONTAL BOUNDARY TO OUR SOUTH AS IT
HAS STALLED OUT AND LOW LEVEL CONVERGENCE CONTINUES TO WEAKEN.
THIS FEATURE WILL BECOME INCREASINGLY DISORGANIZED AND MAY WASH OUT
AS IT LIFTS NORTHWARD THROUGH THE DAY MONDAY. CONSEQUENTLY...FOCUS
OF PRECIPITATION THROUGH THE REMAINDER OF THE OVERNIGHT IS
INCREASINGLY BECOMING H850 BOUNDARY POSITIONED ACROSS OUR NORTH AS
IT ALSO LIFTS TO THE NORTH. THEREAFTER WE WILL HAVE TO WAIT FOR
BETTER FORCING FROM THE MAIN STORM SYSTEM LOCATED OVER THE SOUTHERN
PLAINS AS IT SHIFTS TO THE NORTH AND EAST INTO THE MIDWEST AND
EVENTUALLY PULLS A TROUGH THROUGH THE OHIO VALLEY. GRIDS AND ZONE
PACKAGE HAVE BEEN UPDATED TO REFLECT LATEST THOUGHTS.
UPDATE ISSUED AT 931 PM EST SUN DEC 27 2015
FORECAST IS IN DECENT SHAPE THIS EVENING. SHOWER ACTIVITY HAS
BEEN PICKING UP ACROSS THE SOUTH ALONG THE SFC FRONTAL BOUNDARY AS
IT CONTINUES TO EDGE CLOSER...BUT MORE SLOWLY TOWARDS THE KY/TN
STATE LINE. SEEING EVIDENCE THAT SOUTHERLY LOW LEVEL FLOW MAY
ALREADY BE STRENGTHENING TO OUR WEST ACROSS WESTERN/CNTRL KY...
HINTING AT THE POSSIBILITY OF SOME REDEVELOPMENT OF SHOWER
ACTIVITY THROUGH THE PREDAWN HOURS OVER OUR WESTERN MOST COUNTIES.
THIS FACTOR WOULD ALSO EXPLAIN THE PERSISTENT YET LIGHT NATURE OF
ACTIVITY ACROSS OUR NORTH...ATTM A BIT MORE THAN EXPECTED EARLIER
THIS EVENING. MOST RECENT HRRR SUPPORTS CURRENT LINE OF THINKING
AS WELL. HAVE MADE SOME MINOR ADJUSTMENTS TO THE GRIDS AND
FORECAST PACKAGE FOR LATEST THOUGHTS AND HOURLY TRENDS.
UPDATE ISSUED AT 545 PM EST SUN DEC 27 2015
A FRONTAL BOUNDARY IS CURRENTLY DROPPING SOUTHWARD THROUGH OUR
FORECAST AREA AND IS EXPECTED TO MOVE SOUTH OF THE HAL ROGERS
PARKWAY/HWY 80 BY EARLY MORNING MONDAY...06-09Z. HOWEVER...WE ARE
LOSING MOST OF THE FORCING ALONG THIS BOUNDARY AS H925-H850 WINDS
WEAKEN FROM AROUND 45 KTS TO LESS THAN 15 KTS THROUGH THE EVENING
HOURS. THEREFORE EXPECT BAND OF RAINFALL TO OUR NORTH TO DIMINISH
WITH TIME AS LLJ WEAKENS. THERE IS ENOUGH CONVERGENCE ALONG THE
BOUNDARY ITSELF HOWEVER TO ALLOW SCATTERED SHOWERS TO DEVELOP
ALONG THE FRONT AS IT PUSHES SOUTHWARD. LLJ STRENGTHENS AGAIN
TOWARDS DAWN WHICH WILL BE RESPONSIBLE FOR REDEVELOPMENT OF
CONVECTION MOVING IN FROM THE WEST...SOUTHWEST. SHORT TERM MODELS
HAVE PICKED UP WELL ON THIS SCENARIO...AND CURRENT RADAR TRENDS
ESPECIALLY SUPPORTS THIS LINE OF THINKING FOR THE IMMEDIATE SHORT
TERM PERIOD. HAVE ADJUSTED GRIDS AND ZONES ACCORDINGLY.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 215 PM EST SUN DEC 27 2015
18Z SFC ANALYSIS SHOWS THE INITIAL LOW PRESSURE WAVE PASSING OUT
OF KENTUCKY. THIS IS DRAGGING THE FRONT OUR WAY FROM THE WEST AND
NORTH. SO FAR...THOUGH...THE CONVECTION ASSOCIATED WITH THIS
BOUNDARY FOR EAST KENTUCKY HAS MAINLY JUST BEEN SOME SCATTERED
LIGHT SHOWERS AFFECTING LOCATIONS NORTH OF INTERSTATE 64. FOR THE
MOST PART OUR AREA ENJOYED A VERY WARM AND BREEZY DAY WITH
TEMPERATURES PEAKING IN THE MID 70S. DEW POINTS WERE QUITE
SUMMER- LIKE IN THE UPPER 50S AND LOWER 60S FOR MOST PLACES. WINDS
GUSTED TO BETWEEN 20 AND 25 MPH FROM THE SOUTHWEST FOR LOCATIONS
THAT SAW ANY SUNSHINE FROM BETWEEN BROKEN DECKS OF MID AND HIGH
LAYER CLOUDS. THE RIVERS THROUGH EAST KENTUCKY CONTINUE TO RUN
HIGH BUT ARE ALL DROPPING.
THE MODELS ARE IN GOOD AGREEMENT ALOFT AS THEY ALL ROLL A VERY
STRONG...AND FAR SOUTH...CLOSED LOW FROM THE BIG BEND REGION OF
TEXAS NORTH NORTHEAST INTO THE UPPER MIDWEST AND EVENTUALLY TO THE
WESTERN GREAT LAKES BY TUESDAY MORNING. THE MODELS CLUSTER BETTER
WITH THIS LOW/S TRACK AND STRENGTH THAN THEY DID 24 HOURS AGO.
ACCORDINGLY...CONFIDENCE HAS INCREASED IN THEIR CONSENSUS
SOLUTION. FOR EAST KENTUCKY...WE WILL ENDURE A GLANCING BLOW FROM
THIS SYSTEM WITH ITS MAIN EFFECTS PASSING THROUGH LATER MONDAY
INTO EARLY TUESDAY MORNING AS ITS VORT STREAM CROSSES KENTUCKY.
OTHERWISE...BROAD AND DEEP SOUTHWEST FLOW WILL BE THE RULE INTO
MONDAY AFTERNOON SUSTAINING THE WARM AND MOIST CONDITIONS. GIVEN
THE BETTER MODEL AGREEMENT HAVE FAVORED A BLENDED SOLUTION WITH
EMPHASIS ON THE NAM12 FOR WEATHER DETAILS AND THE HRRR...WITH A
GRAIN OF SALT...IN THE NEAR TERM.
SENSIBLE WEATHER WILL FEATURE A WARM EVENING FOR MOST OF THE AREA
BUT A COOLING AND WETTER ONE IN THE NORTH AND WEST AS THAT
FRONT/S IMPACTS ARE FELT. IN TIME...TONIGHT...THIS BOUNDARY WILL
BRING COOLER CONDITIONS DEEPER INTO EAST KENTUCKY ALONG WITH
SCATTERED TO NUMEROUS SHOWERS. CANNOT RULE OUT A STRAY
THUNDERSTORM DURING THE NIGHT...BUT CHANCES ARE PRETTY SMALL. FOR
MONDAY...ADDITIONAL SHOWERS AND PERHAPS A THUNDERSTORM WILL BE
AROUND INTO THE AFTERNOON OUT AHEAD OF AN APPROACHING AND MUCH
STRONGER COLD FRONT. THIS FRONT WILL BRING THE BULK OF THE RAIN
EXPECTED ACROSS EAST KENTUCKY FOR THIS PERIOD...MAINLY IN THE
EVENING MONDAY AND THE OVERNIGHT HOURS INTO EARLY TUESDAY. AT
THAT POINT THE WHOLE WEATHER SYSTEM WILL BE PROGRESSIVE ENOUGH TO
LIKELY PRECLUDE ANY MORE THAN JUST SOME BRIEF NUISANCE FLOODING.
AS SUCH...WILL HOLD OFF ON ANY FLOOD WATCHES FOR THE TIME BEING.
SHOULD THE SHOWER ACTIVITY BECOME MORE ROBUST TONIGHT OR INTO THE
DAY MONDAY CONDITIONS WOULD THEN BE MORE RIPE FOR FLOODING AND A
WATCH MAY BE NEEDED. FOR NOW WILL CONTINUE THE CURRENT ESF
DETAILING THE RAINFALL CONCERNS THROUGH TUESDAY. WARM TEMPERATURES
WILL CONTINUE FOR MOST OF THE AREA ON MONDAY AHEAD OF THE MAIN
COLD FRONT WITH DAILY RECORDS THREATENED AGAIN.
AGAIN STARTED WITH THE SHORTBLEND FOR TEMPERATURES AND DEW POINTS
THROUGH MONDAY MORNING AND THE SUPERBLEND THEREAFTER THROUGH
MONDAY NIGHT. DID HAVE TO ADJUST THESE IN THE NEAR TERM TO
CAPTURE THE CURRENT WARMTH FOR MOST OF THE AREA. ALSO MADE SOME
MINOR CHANGES TO THE LOWS OVER OUR SOUTHERN COUNTIES TONIGHT WHERE
A SMALL RIDGE AND VALLEY DIFFERENCE IS EXPECTED TO SET UP IN THE
EVENING BEFORE THE THICKER AND LOWER CLOUDS MOVE IN...ALONG WITH
THE HIGHER PCPN CHANGES. AS FOR POPS...ENDED UP MOST SIMILAR TO
THE MET NUMBERS...BUT NOT TOO FAR FROM THE MAV/S THROUGH THE
PERIOD.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 306 PM EST SUN DEC 27 2015
THE MODELS WERE IN GOOD AGREEMENT IN THE LONG TERM THIS TIME AROUND.
THE CONSENSUS IS FOR A LARGE WELL DEVELOPED AREA OF LOW PRESSURE TO
MOVE QUICKLY ACROSS THE GREAT LAKES REGION AND INTO NE ENGLAND
TUESDAY AND TUESDAY NIGHT. THE LOW WILL DRAG A SURFACE COLD FRONT
EASTWARD ACROSS EASTERN KENTUCKY ON TUESDAY. SCATTERED RAIN SHOWERS
ARE EXPECTED TO MOVE ACROSS THE AREA AS WELL JUST BEHIND THE
DEPARTING FRONTAL BOUNDARY. AFTER A VERY BRIEF LULL...ANOTHER
WEATHER SYSTEM IS EXPECTED TO APPROACH FROM THE SOUTHWEST AND MOVE
UP THE SPINE OF THE APPALACHIAN MOUNTAINS TUESDAY NIGHT AND
WEDNESDAY. THIS SECOND WEATHER SYSTEM SHOULD BRING SCATTERED TO
NUMEROUS RAIN SHOWERS TO THE AREA THROUGH THE MIDDLE OF THE WEEK.
THE QUESTION WILL BE THE AMOUNT OF MOISTURE AVAILABLE TO THE SYSTEM
AS IT MOVES THROUGH. AT THIS TIME BASED ON THE MODEL AGREEMENT...IT
SEEMED REASONABLE TO HAVE FAIRLY HIGH POPS IN THE FORECAST FOR
TUESDAY NIGHT AND WEDNESDAY. TEMPERATURES WILL REMAIN WARM ENOUGH TO
KEEP EVERYTHING IN LIQUID FORM. ONCE THIS SECOND SYSTEM EXITS THE
AREA ON WEDNESDAY MORNING...THE REST OF THE WEEK SHOULD BE DRY AND
MUCH COOLER THAN WE HAVE BEEN USED TO IN RECENT WEEKS.
TEMPERATURES WILL BE WELL ABOVE NORMAL TUESDAY AND WEDNESDAY...AS AN
UNSEASONABLY WARM AND MOIST AIR MASS REMAINS IN PLACE ACROSS THE
REGION. WE CAN EXPECT MUCH COOLER TEMPERATURES ON THURSDAY AS COLD
AIR SPILLS INTO THE AREA BEHIND A DEPARTING AREA OF LOW PRESSURE. A
MAJOR COOL DOWN WILL THEN BE ON TAP FOR FRIDAY AND SATURDAY...AS A
CANADIAN AS MASS SETTLES OVER THE REGION. HIGHS TO END THE WEEK AND
INTO THE UPCOMING WEEKEND WILL LIKELY BE SEVERAL DEGREES COOLER THAN
NORMAL ACROSS EASTERN KENTUCKY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1225 AM EST MON DEC 28 2015
CURRENTLY...THE COLD FRONT REMAINS IN PLACE ACROSS EASTERN
KENTUCKY TONIGHT WITH LOW LEVEL CLOUD COVER AND FEW SHOWERS
MOVING THROUGH THE AREA. LATER TONIGHT...A WARM FRONT WILL DEVELOP
AND LIFT THROUGH THE AREA. THIS WILL CREATE SOME SOUTHEAST
DOWNSLOPE WINDS ACROSS THE AREA AND CAUSE LOW LEVEL CIGS TO LIFT
BY LATE MORNING AND EVEN SOME VFR CIGS DEVELOPING BY MIDDAY. THE
COLD FRONT WILL THEN PUSH THROUGH THE AREA BY LATE DAY MONDAY
DROPPING CIGS AND VIS AGAIN. WINDS WILL BE MAINLY OUT OF THE SOUTH
BEFORE RAMPING UP LATER ON MONDAY AND EVEN SHIFTING TO THE
SOUTHWEST AS THE FRONT MOVES THROUGH.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...RAY
SHORT TERM...GREIF
LONG TERM...AR
AVIATION...SHALLENBERGER
AREA FORECAST DISCUSSION
NWS JACKSON KY
1225 AM EST MON DEC 28 2015
.UPDATE...
ISSUED AT 931 PM EST SUN DEC 27 2015
FORECAST IS IN DECENT SHAPE THIS EVENING. SHOWER ACTIVITY HAS
BEEN PICKING UP ACROSS THE SOUTH ALONG THE SFC FRONTAL BOUNDARY AS
IT CONTINUES TO EDGE CLOSER...BUT MORE SLOWLY TOWARDS THE KY/TN
STATE LINE. SEEING EVIDENCE THAT SOUTHERLY LOW LEVEL FLOW MAY
ALREADY BE STRENGTHENING TO OUR WEST ACROSS WESTERN/CNTRL KY...
HINTING AT THE POSSIBILITY OF SOME REDEVELOPMENT OF SHOWER
ACTIVITY THROUGH THE PREDAWN HOURS OVER OUR WESTERN MOST COUNTIES.
THIS FACTOR WOULD ALSO EXPLAIN THE PERSISTENT YET LIGHT NATURE OF
ACTIVITY ACROSS OUR NORTH...ATTM A BIT MORE THAN EXPECTED EARLIER
THIS EVENING. MOST RECENT HRRR SUPPORTS CURRENT LINE OF THINKING
AS WELL. HAVE MADE SOME MINOR ADJUSTMENTS TO THE GRIDS AND
FORECAST PACKAGE FOR LATEST THOUGHTS AND HOURLY TRENDS.
UPDATE ISSUED AT 545 PM EST SUN DEC 27 2015
A FRONTAL BOUNDARY IS CURRENTLY DROPPING SOUTHWARD THROUGH OUR
FORECAST AREA AND IS EXPECTED TO MOVE SOUTH OF THE HAL ROGERS
PARKWAY/HWY 80 BY EARLY MORNING MONDAY...06-09Z. HOWEVER...WE ARE
LOSING MOST OF THE FORCING ALONG THIS BOUNDARY AS H925-H850 WINDS
WEAKEN FROM AROUND 45 KTS TO LESS THAN 15 KTS THROUGH THE EVENING
HOURS. THEREFORE EXPECT BAND OF RAINFALL TO OUR NORTH TO DIMINISH
WITH TIME AS LLJ WEAKENS. THERE IS ENOUGH CONVERGENCE ALONG THE
BOUNDARY ITSELF HOWEVER TO ALLOW SCATTERED SHOWERS TO DEVELOP
ALONG THE FRONT AS IT PUSHES SOUTHWARD. LLJ STRENGTHENS AGAIN
TOWARDS DAWN WHICH WILL BE RESPONSIBLE FOR REDEVELOPMENT OF
CONVECTION MOVING IN FROM THE WEST...SOUTHWEST. SHORT TERM MODELS
HAVE PICKED UP WELL ON THIS SCENARIO...AND CURRENT RADAR TRENDS
ESPECIALLY SUPPORTS THIS LINE OF THINKING FOR THE IMMEDIATE SHORT
TERM PERIOD. HAVE ADJUSTED GRIDS AND ZONES ACCORDINGLY.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 215 PM EST SUN DEC 27 2015
18Z SFC ANALYSIS SHOWS THE INITIAL LOW PRESSURE WAVE PASSING OUT
OF KENTUCKY. THIS IS DRAGGING THE FRONT OUR WAY FROM THE WEST AND
NORTH. SO FAR...THOUGH...THE CONVECTION ASSOCIATED WITH THIS
BOUNDARY FOR EAST KENTUCKY HAS MAINLY JUST BEEN SOME SCATTERED
LIGHT SHOWERS AFFECTING LOCATIONS NORTH OF INTERSTATE 64. FOR THE
MOST PART OUR AREA ENJOYED A VERY WARM AND BREEZY DAY WITH
TEMPERATURES PEAKING IN THE MID 70S. DEW POINTS WERE QUITE
SUMMER- LIKE IN THE UPPER 50S AND LOWER 60S FOR MOST PLACES. WINDS
GUSTED TO BETWEEN 20 AND 25 MPH FROM THE SOUTHWEST FOR LOCATIONS
THAT SAW ANY SUNSHINE FROM BETWEEN BROKEN DECKS OF MID AND HIGH
LAYER CLOUDS. THE RIVERS THROUGH EAST KENTUCKY CONTINUE TO RUN
HIGH BUT ARE ALL DROPPING.
THE MODELS ARE IN GOOD AGREEMENT ALOFT AS THEY ALL ROLL A VERY
STRONG...AND FAR SOUTH...CLOSED LOW FROM THE BIG BEND REGION OF
TEXAS NORTH NORTHEAST INTO THE UPPER MIDWEST AND EVENTUALLY TO THE
WESTERN GREAT LAKES BY TUESDAY MORNING. THE MODELS CLUSTER BETTER
WITH THIS LOW/S TRACK AND STRENGTH THAN THEY DID 24 HOURS AGO.
ACCORDINGLY...CONFIDENCE HAS INCREASED IN THEIR CONSENSUS
SOLUTION. FOR EAST KENTUCKY...WE WILL ENDURE A GLANCING BLOW FROM
THIS SYSTEM WITH ITS MAIN EFFECTS PASSING THROUGH LATER MONDAY
INTO EARLY TUESDAY MORNING AS ITS VORT STREAM CROSSES KENTUCKY.
OTHERWISE...BROAD AND DEEP SOUTHWEST FLOW WILL BE THE RULE INTO
MONDAY AFTERNOON SUSTAINING THE WARM AND MOIST CONDITIONS. GIVEN
THE BETTER MODEL AGREEMENT HAVE FAVORED A BLENDED SOLUTION WITH
EMPHASIS ON THE NAM12 FOR WEATHER DETAILS AND THE HRRR...WITH A
GRAIN OF SALT...IN THE NEAR TERM.
SENSIBLE WEATHER WILL FEATURE A WARM EVENING FOR MOST OF THE AREA
BUT A COOLING AND WETTER ONE IN THE NORTH AND WEST AS THAT
FRONT/S IMPACTS ARE FELT. IN TIME...TONIGHT...THIS BOUNDARY WILL
BRING COOLER CONDITIONS DEEPER INTO EAST KENTUCKY ALONG WITH
SCATTERED TO NUMEROUS SHOWERS. CANNOT RULE OUT A STRAY
THUNDERSTORM DURING THE NIGHT...BUT CHANCES ARE PRETTY SMALL. FOR
MONDAY...ADDITIONAL SHOWERS AND PERHAPS A THUNDERSTORM WILL BE
AROUND INTO THE AFTERNOON OUT AHEAD OF AN APPROACHING AND MUCH
STRONGER COLD FRONT. THIS FRONT WILL BRING THE BULK OF THE RAIN
EXPECTED ACROSS EAST KENTUCKY FOR THIS PERIOD...MAINLY IN THE
EVENING MONDAY AND THE OVERNIGHT HOURS INTO EARLY TUESDAY. AT
THAT POINT THE WHOLE WEATHER SYSTEM WILL BE PROGRESSIVE ENOUGH TO
LIKELY PRECLUDE ANY MORE THAN JUST SOME BRIEF NUISANCE FLOODING.
AS SUCH...WILL HOLD OFF ON ANY FLOOD WATCHES FOR THE TIME BEING.
SHOULD THE SHOWER ACTIVITY BECOME MORE ROBUST TONIGHT OR INTO THE
DAY MONDAY CONDITIONS WOULD THEN BE MORE RIPE FOR FLOODING AND A
WATCH MAY BE NEEDED. FOR NOW WILL CONTINUE THE CURRENT ESF
DETAILING THE RAINFALL CONCERNS THROUGH TUESDAY. WARM TEMPERATURES
WILL CONTINUE FOR MOST OF THE AREA ON MONDAY AHEAD OF THE MAIN
COLD FRONT WITH DAILY RECORDS THREATENED AGAIN.
AGAIN STARTED WITH THE SHORTBLEND FOR TEMPERATURES AND DEW POINTS
THROUGH MONDAY MORNING AND THE SUPERBLEND THEREAFTER THROUGH
MONDAY NIGHT. DID HAVE TO ADJUST THESE IN THE NEAR TERM TO
CAPTURE THE CURRENT WARMTH FOR MOST OF THE AREA. ALSO MADE SOME
MINOR CHANGES TO THE LOWS OVER OUR SOUTHERN COUNTIES TONIGHT WHERE
A SMALL RIDGE AND VALLEY DIFFERENCE IS EXPECTED TO SET UP IN THE
EVENING BEFORE THE THICKER AND LOWER CLOUDS MOVE IN...ALONG WITH
THE HIGHER PCPN CHANGES. AS FOR POPS...ENDED UP MOST SIMILAR TO
THE MET NUMBERS...BUT NOT TOO FAR FROM THE MAV/S THROUGH THE
PERIOD.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 306 PM EST SUN DEC 27 2015
THE MODELS WERE IN GOOD AGREEMENT IN THE LONG TERM THIS TIME AROUND.
THE CONSENSUS IS FOR A LARGE WELL DEVELOPED AREA OF LOW PRESSURE TO
MOVE QUICKLY ACROSS THE GREAT LAKES REGION AND INTO NE ENGLAND
TUESDAY AND TUESDAY NIGHT. THE LOW WILL DRAG A SURFACE COLD FRONT
EASTWARD ACROSS EASTERN KENTUCKY ON TUESDAY. SCATTERED RAIN SHOWERS
ARE EXPECTED TO MOVE ACROSS THE AREA AS WELL JUST BEHIND THE
DEPARTING FRONTAL BOUNDARY. AFTER A VERY BRIEF LULL...ANOTHER
WEATHER SYSTEM IS EXPECTED TO APPROACH FROM THE SOUTHWEST AND MOVE
UP THE SPINE OF THE APPALACHIAN MOUNTAINS TUESDAY NIGHT AND
WEDNESDAY. THIS SECOND WEATHER SYSTEM SHOULD BRING SCATTERED TO
NUMEROUS RAIN SHOWERS TO THE AREA THROUGH THE MIDDLE OF THE WEEK.
THE QUESTION WILL BE THE AMOUNT OF MOISTURE AVAILABLE TO THE SYSTEM
AS IT MOVES THROUGH. AT THIS TIME BASED ON THE MODEL AGREEMENT...IT
SEEMED REASONABLE TO HAVE FAIRLY HIGH POPS IN THE FORECAST FOR
TUESDAY NIGHT AND WEDNESDAY. TEMPERATURES WILL REMAIN WARM ENOUGH TO
KEEP EVERYTHING IN LIQUID FORM. ONCE THIS SECOND SYSTEM EXITS THE
AREA ON WEDNESDAY MORNING...THE REST OF THE WEEK SHOULD BE DRY AND
MUCH COOLER THAN WE HAVE BEEN USED TO IN RECENT WEEKS.
TEMPERATURES WILL BE WELL ABOVE NORMAL TUESDAY AND WEDNESDAY...AS AN
UNSEASONABLY WARM AND MOIST AIR MASS REMAINS IN PLACE ACROSS THE
REGION. WE CAN EXPECT MUCH COOLER TEMPERATURES ON THURSDAY AS COLD
AIR SPILLS INTO THE AREA BEHIND A DEPARTING AREA OF LOW PRESSURE. A
MAJOR COOL DOWN WILL THEN BE ON TAP FOR FRIDAY AND SATURDAY...AS A
CANADIAN AS MASS SETTLES OVER THE REGION. HIGHS TO END THE WEEK AND
INTO THE UPCOMING WEEKEND WILL LIKELY BE SEVERAL DEGREES COOLER THAN
NORMAL ACROSS EASTERN KENTUCKY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1225 AM EST MON DEC 28 2015
CURRENTLY...THE COLD FRONT REMAINS IN PLACE ACROSS EASTERN
KENTUCKY TONIGHT WITH LOW LEVEL CLOUD COVER AND FEW SHOWERS
MOVING THROUGH THE AREA. LATER TONIGHT...A WARM FRONT WILL DEVELOP
AND LIFT THROUGH THE AREA. THIS WILL CREATE SOME SOUTHEAST
DOWNSLOPE WINDS ACROSS THE AREA AND CAUSE LOW LEVEL CIGS TO LIFT
BY LATE MORNING AND EVEN SOME VFR CIGS DEVELOPING BY MIDDAY. THE
COLD FRONT WILL THEN PUSH THROUGH THE AREA BY LATE DAY MONDAY
DROPPING CIGS AND VIS AGAIN. WINDS WILL BE MAINLY OUT OF THE SOUTH
BEFORE RAMPING UP LATER ON MONDAY AND EVEN SHIFTING TO THE
SOUTHWEST AS THE FRONT MOVES THROUGH.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...RAY
SHORT TERM...GREIF
LONG TERM...AR
AVIATION...SHALLENBERGER
AREA FORECAST DISCUSSION
NWS LAKE CHARLES LA
1147 PM CST SUN DEC 27 2015
.UPDATE...BEAUREGARD, CALCASIEU, AND JEFF DAVIS HAVE BEEN SHAVED
OUT OF THE WATCH AS THE FRONT HAS NOW PASSED THESE ZONES.
&&
.PREV DISCUSSION... /ISSUED 1141 PM CST SUN DEC 27 2015/
DISCUSSION...
FOR THE 28/06Z TAF ISSUANCE.
AVIATION...
THE COLD FRONT/WIND SHIFT LINE HAS PASSED THROUGH KBPT/KLCH AND IS
NOT ACCELERATING OFF TO THE EAST-NORTHEAST...AND IS EXPECTED TO
PASS THROUGH KAEX/LFT/KARA BETWEEN START OF TAF PERIOD AND 28/08Z.
A SEMI-SQUALL LINE FEATURE WILL ACCOMPANY THE FRONT...WITH WINDS
SHIFTING TO THE SOUTHWEST AND GUSTING TO NEAR 40 KNOTS...WITH
HEAVY RAINFALL LOWERING VISIBILITIES TO IFR LEVELS. FOR PLACES A COUPLE
OF HOURS AHEAD OF THE FRONT...STRONG SOUTH WINDS...OCCASIONAL
SHOWERS AND MVFR CEILINGS WILL PREVAIL. BEHIND THE FRONT...GUSTY
SOUTHWEST TO WEST WINDS WILL PREVAIL WITH OCCASIONAL SHOWERS FOR
ABOUT 3 HOURS AFTER FRONTAL PASSAGE...WITH MVFR CEILINGS.
ON MONDAY...WRAP AROUND CLOUDS SHOULD KEEP MVFR CEILINGS IN PLACE
UNTIL LATE AFTERNOON OR EVENING HOURS.
RUA
PREV DISCUSSION... /ISSUED 1010 PM CST SUN DEC 27 2015/
UPDATE...THE COLD FRONT AND THIN LINE OF RAIN AND THUNDERSTORMS
IS ROUGHLY FROM NEWTON, TX TO CAMERON, LA AND IS CONTINUING TO
SLOWLY MOVE EAST, HOWEVER AS THE UPPER LOW OVER TX DRAWS CLOSER
THE LINE IS EXPECTED TO SPEED UP. A SLIGHT RISK OF SEVERE WX
STILL EXISTS ALONG AND AHEAD OF THE FRONT, AND A NEW WATCH HAS
BEEN ISSUED. THE THREAT FOR THE WESTERN MOST LA PARISHES SHOULD
COME TO AN END OVER THE NEXT HOUR OR TWO WITH THE THREAT ENDING
ACROSS CENTRAL/SOUTH CENTRAL LA FROM MIDNIGHT INTO THE EARLY
MORNING HOURS.
THE GALE HAS BEEN EXPANDED OVER THE COASTAL WATERS. THE LATEST
GUIDANCE INDICATES FREQUENT GALE FORCE GUST EVEN ACROSS THE
NEARSHORE WATERS THROUGH 12Z AS A MUCH COLDER AIR MASS MOVES OVER
THE WARM WATER.
PREV DISCUSSION... /ISSUED 313 PM CST SUN DEC 27 2015/
DISCUSSION...
SHORT TERM...TONIGHT THROUGH MONDAY
THUNDERSTORMS ARE ORGANIZING ACROSS SE TEXAS LATE THIS AFTERNOON.
LATEST SHORT TERM GUIDANCE INCLUDING HRRR HAS CONVECTIVE LINE MOVING
THROUGH SW LOUISIANA THIS EVENING AND THROUGH ACADIANA AROUND
MIDNIGHT. WILL BE MONITORING FOR ROTATING DISCRETE CELLS AHEAD OF
LINE BUT BELIEVE MOST IMPACTS WILL BE FROM PASSING SQUALL LINE LATE
THIS AFTERNOON AND TONIGHT.
WILL EXTEND WIND ADVISORY UNTIL 12Z AS TIGHT GRADIENT IS
FORECASTED TO CONTINUE AS WINDS BECOME WNW.
THE PASSAGE OF THE LOW/FRONTAL BOUNDARY WILL FINALLY BRING AN END
TO THE UNSEASONABLY WARM LATE DECEMBER WEATHER. DRIER AND MUCH
COLDER CONDITIONS ARE EXPECTED BEGINNING MONDAY. MOST OF THE
FORECAST AREA IS EXPECTED TO REMAIN IN THE 50S FOR HIGHS. WITH A
COLDER AIR MASS IN PLACE AND HIGH PRESSURE OVER THE AREA TUESDAY
MORNING...WILL NEED THE MONITOR FOR THE POTENTIAL OF FREEZING
TEMPERATURES OVER THE TEXAS LAKES REGION AND CENTRAL LOUISIANA.
LONG TERM...TUESDAY THROUGH SUNDAY
MAIN FORECAST ISSUE IN THE LONG TERM WILL BE POPS.
MODELS INDICATE A SERIES OF PROGRESSIVE UPPER TROUGHS MOVING THROUGH
THE CENTRAL U.S. THROUGH THE WEEK. A STRONG SOUTHERN JET WILL BE
OVER THE SOUTHERN PLAINS AS WELL. WHILE PWATS ARE FORECASTED TO BE
BELOW AN INCH...THERE WILL BE A GOOD MOISTURE GRADIENT OVER THE
NORTHERN GULF. THIS COMBINED WITH SUFFICIENT PACIFIC MOISTURE WILL
BRING SCATTERED SHOWERS TUESDAY NIGHT AND WEDNESDAY. THE BEST CHANCE
FOR RAIN WILL BE OVER LOWER ACADIANA. WITH THE STRONG UPPER JET
OVER THE AREA LATE IN THE WEEK...WILL HAVE LOW POPS MAINLY OVER
COASTAL AREAS. TEMPERATURES THROUGH THE WEEK WILL TREND BELOW
NORMAL AS HIGH TEMPERATURES WILL BE MOSTLY IN THE 50S.
MARINE...ONLY CHANGES TO HAZARDS WILL BE TO EXTEND SCA FOR BAYS
UNTIL 12Z. SUSTAINED FORECAST WINDS WILL BE CLOSE ENOUGH FOR GALE
WARNING OFFSHORE BEGINNING AT 00Z.
STRONG ONSHORE FLOW WILL GRADUALLY SHIFT TO THE NW AS LOW PRESSURE
MOVES THROUGH THE AKLATX TONIGHT. HIGH PRESSURE WILL BUILD
BEGINNING MONDAY AFTERNOON ALLOWING FOR WINDS/WAVES TO DIMINISH.
STRONG OFFSHORE FLOW WILL EMERGE ON WEDNESDAY AS REINFORCING SURGE
OF COLD AIR MOVES OVER THE GULF. GRADIENT WILL LIKELY FURTHER
TIGHTEN AS A LOW PRESSURE SYSTEM TRIES TO ORGANIZE OVER THE BAY OF
CAMPECHE. WITH THE GOOD GRADIENT FORECASTED TO REMAIN OVER THE AREA
THROUGH THE WEEKEND...AN EXTENDED PERIOD OF SCA CONDITIONS APPEARS
LIKELY.
&&
.PRELIMINARY POINT TEMPS/POPS...
AEX 51 55 37 57 / 100 20 10 10
LCH 48 57 39 59 / 90 10 10 10
LFT 54 60 42 60 / 90 20 10 10
BPT 45 56 39 59 / 90 10 10 10
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...WIND ADVISORY UNTIL 6 AM CST MONDAY FOR LAZ027>033-041>045-
052>055-073-074.
COASTAL FLOOD ADVISORY UNTIL 6 AM CST MONDAY FOR LAZ041-052>054-
073-074.
TX...WIND ADVISORY UNTIL 6 AM CST MONDAY FOR TXZ180-201-215-216-
259>262.
COASTAL FLOOD ADVISORY UNTIL 6 AM CST MONDAY FOR TXZ215-216.
GM...SMALL CRAFT ADVISORY FROM 6 AM TO NOON CST MONDAY FOR GMZ450-452-
455-470-472-475.
GALE WARNING UNTIL 6 AM CST MONDAY FOR GMZ450-452-455-470-472-
475.
SMALL CRAFT ADVISORY UNTIL 6 AM CST MONDAY FOR GMZ430-432-435.
&&
$$
PUBLIC...05
AREA FORECAST DISCUSSION
NWS LAKE CHARLES LA
1141 PM CST SUN DEC 27 2015
.DISCUSSION...
FOR THE 28/06Z TAF ISSUANCE.
&&
.AVIATION...
THE COLD FRONT/WIND SHIFT LINE HAS PASSED THROUGH KBPT/KLCH AND IS
NOT ACCELERATING OFF TO THE EAST-NORTHEAST...AND IS EXPECTED TO
PASS THROUGH KAEX/LFT/KARA BETWEEN START OF TAF PERIOD AND 28/08Z.
A SEMI-SQUALL LINE FEATURE WILL ACCOMPANY THE FRONT...WITH WINDS
SHIFTING TO THE SOUTHWEST AND GUSTING TO NEAR 40 KNOTS...WITH
HEAVY RAINFALL LOWERING VISIBILITIES TO IFR LEVELS. FOR PLACES A COUPLE
OF HOURS AHEAD OF THE FRONT...STRONG SOUTH WINDS...OCCASIONAL
SHOWERS AND MVFR CEILINGS WILL PREVAIL. BEHIND THE FRONT...GUSTY
SOUTHWEST TO WEST WINDS WILL PREVAIL WITH OCCASIONAL SHOWERS FOR
ABOUT 3 HOURS AFTER FRONTAL PASSAGE...WITH MVFR CEILINGS.
ON MONDAY...WRAP AROUND CLOUDS SHOULD KEEP MVFR CEILINGS IN PLACE
UNTIL LATE AFTERNOON OR EVENING HOURS.
RUA
&&
.PREV DISCUSSION... /ISSUED 1010 PM CST SUN DEC 27 2015/
UPDATE...THE COLD FRONT AND THIN LINE OF RAIN AND THUNDERSTORMS
IS ROUGHLY FROM NEWTON, TX TO CAMERON, LA AND IS CONTINUING TO
SLOWLY MOVE EAST, HOWEVER AS THE UPPER LOW OVER TX DRAWS CLOSER
THE LINE IS EXPECTED TO SPEED UP. A SLIGHT RISK OF SEVERE WX
STILL EXISTS ALONG AND AHEAD OF THE FRONT, AND A NEW WATCH HAS
BEEN ISSUED. THE THREAT FOR THE WESTERN MOST LA PARISHES SHOULD
COME TO AN END OVER THE NEXT HOUR OR TWO WITH THE THREAT ENDING
ACROSS CENTRAL/SOUTH CENTRAL LA FROM MIDNIGHT INTO THE EARLY
MORNING HOURS.
THE GALE HAS BEEN EXPANDED OVER THE COASTAL WATERS. THE LATEST
GUIDANCE INDICATES FREQUENT GALE FORCE GUST EVEN ACROSS THE
NEARSHORE WATERS THROUGH 12Z AS A MUCH COLDER AIR MASS MOVES OVER
THE WARM WATER.
PREV DISCUSSION... /ISSUED 313 PM CST SUN DEC 27 2015/
DISCUSSION...
SHORT TERM...TONIGHT THROUGH MONDAY
THUNDERSTORMS ARE ORGANIZING ACROSS SE TEXAS LATE THIS AFTERNOON.
LATEST SHORT TERM GUIDANCE INCLUDING HRRR HAS CONVECTIVE LINE MOVING
THROUGH SW LOUISIANA THIS EVENING AND THROUGH ACADIANA AROUND
MIDNIGHT. WILL BE MONITORING FOR ROTATING DISCRETE CELLS AHEAD OF
LINE BUT BELIEVE MOST IMPACTS WILL BE FROM PASSING SQUALL LINE LATE
THIS AFTERNOON AND TONIGHT.
WILL EXTEND WIND ADVISORY UNTIL 12Z AS TIGHT GRADIENT IS
FORECASTED TO CONTINUE AS WINDS BECOME WNW.
THE PASSAGE OF THE LOW/FRONTAL BOUNDARY WILL FINALLY BRING AN END
TO THE UNSEASONABLY WARM LATE DECEMBER WEATHER. DRIER AND MUCH
COLDER CONDITIONS ARE EXPECTED BEGINNING MONDAY. MOST OF THE
FORECAST AREA IS EXPECTED TO REMAIN IN THE 50S FOR HIGHS. WITH A
COLDER AIR MASS IN PLACE AND HIGH PRESSURE OVER THE AREA TUESDAY
MORNING...WILL NEED THE MONITOR FOR THE POTENTIAL OF FREEZING
TEMPERATURES OVER THE TEXAS LAKES REGION AND CENTRAL LOUISIANA.
LONG TERM...TUESDAY THROUGH SUNDAY
MAIN FORECAST ISSUE IN THE LONG TERM WILL BE POPS.
MODELS INDICATE A SERIES OF PROGRESSIVE UPPER TROUGHS MOVING THROUGH
THE CENTRAL U.S. THROUGH THE WEEK. A STRONG SOUTHERN JET WILL BE
OVER THE SOUTHERN PLAINS AS WELL. WHILE PWATS ARE FORECASTED TO BE
BELOW AN INCH...THERE WILL BE A GOOD MOISTURE GRADIENT OVER THE
NORTHERN GULF. THIS COMBINED WITH SUFFICIENT PACIFIC MOISTURE WILL
BRING SCATTERED SHOWERS TUESDAY NIGHT AND WEDNESDAY. THE BEST CHANCE
FOR RAIN WILL BE OVER LOWER ACADIANA. WITH THE STRONG UPPER JET
OVER THE AREA LATE IN THE WEEK...WILL HAVE LOW POPS MAINLY OVER
COASTAL AREAS. TEMPERATURES THROUGH THE WEEK WILL TREND BELOW
NORMAL AS HIGH TEMPERATURES WILL BE MOSTLY IN THE 50S.
MARINE...ONLY CHANGES TO HAZARDS WILL BE TO EXTEND SCA FOR BAYS
UNTIL 12Z. SUSTAINED FORECAST WINDS WILL BE CLOSE ENOUGH FOR GALE
WARNING OFFSHORE BEGINNING AT 00Z.
STRONG ONSHORE FLOW WILL GRADUALLY SHIFT TO THE NW AS LOW PRESSURE
MOVES THROUGH THE AKLATX TONIGHT. HIGH PRESSURE WILL BUILD
BEGINNING MONDAY AFTERNOON ALLOWING FOR WINDS/WAVES TO DIMINISH.
STRONG OFFSHORE FLOW WILL EMERGE ON WEDNESDAY AS REINFORCING SURGE
OF COLD AIR MOVES OVER THE GULF. GRADIENT WILL LIKELY FURTHER
TIGHTEN AS A LOW PRESSURE SYSTEM TRIES TO ORGANIZE OVER THE BAY OF
CAMPECHE. WITH THE GOOD GRADIENT FORECASTED TO REMAIN OVER THE AREA
THROUGH THE WEEKEND...AN EXTENDED PERIOD OF SCA CONDITIONS APPEARS
LIKELY.
&&
.PRELIMINARY POINT TEMPS/POPS...
AEX 51 55 37 57 / 100 20 10 10
LCH 48 57 39 59 / 90 10 10 10
LFT 54 60 42 60 / 90 20 10 10
BPT 45 56 39 59 / 90 10 10 10
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...WIND ADVISORY UNTIL 6 AM CST MONDAY FOR LAZ027>033-041>045-
052>055-073-074.
COASTAL FLOOD ADVISORY UNTIL 6 AM CST MONDAY FOR LAZ041-052>054-
073-074.
TX...WIND ADVISORY UNTIL 6 AM CST MONDAY FOR TXZ180-201-215-216-
259>262.
COASTAL FLOOD ADVISORY UNTIL 6 AM CST MONDAY FOR TXZ215-216.
GM...SMALL CRAFT ADVISORY FROM 6 AM TO NOON CST MONDAY FOR GMZ450-452-
455-470-472-475.
GALE WARNING UNTIL 6 AM CST MONDAY FOR GMZ450-452-455-470-472-
475.
SMALL CRAFT ADVISORY UNTIL 6 AM CST MONDAY FOR GMZ430-432-435.
&&
$$
AVIATION...07
AREA FORECAST DISCUSSION
NWS LAKE CHARLES LA
1010 PM CST SUN DEC 27 2015
.UPDATE...THE COLD FRONT AND THIN LINE OF RAIN AND THUNDERSTORMS
IS ROUGHLY FROM NEWTON, TX TO CAMERON, LA AND IS CONTINUING TO
SLOWLY MOVE EAST, HOWEVER AS THE UPPER LOW OVER TX DRAWS CLOSER
THE LINE IS EXPECTED TO SPEED UP. A SLIGHT RISK OF SEVERE WX
STILL EXISTS ALONG AND AHEAD OF THE FRONT, AND A NEW WATCH HAS
BEEN ISSUED. THE THREAT FOR THE WESTERN MOST LA PARISHES SHOULD
COME TO AN END OVER THE NEXT HOUR OR TWO WITH THE THREAT ENDING
ACROSS CENTRAL/SOUTH CENTRAL LA FROM MIDNIGHT INTO THE EARLY
MORNING HOURS.
THE GALE HAS BEEN EXPANDED OVER THE COASTAL WATERS. THE LATEST
GUIDANCE INDICATES FREQUENT GALE FORCE GUST EVEN ACROSS THE
NEARSHORE WATERS THROUGH 12Z AS A MUCH COLDER AIR MASS MOVES OVER
THE WARM WATER.
&&
.PREV DISCUSSION... /ISSUED 531 PM CST SUN DEC 27 2015/
DISCUSSION...
FOR THE 28/00Z TAF ISSUANCE.
AVIATION...
SURFACE LOW OVER NORTHEAST TEXAS WITH TRAILING COLD FRONT AROUND
THE HOUSTON AREA TO OFF INTO THE NORTHWEST GULF WILL CONTINUE TO
GRADUALLY LIFT OFF TO THE NORTHEAST DURING THE EVENING AND
OVERNIGHT. WITHIN A COUPLE OF HOURS OF TIMING...EXPECT THE COLD
FRONT AND ASSOCIATED SQUALL LINE TO MOVE NEAR KBPT BY
28/01Z...KLCH 28/02Z...KAEX 28/03Z AND KLFT/KARA 28/05Z. SHOWERS
AND STORMS ALONG SQUALL LINE WILL HAVE POTENTIAL WIND GUSTS OVER
40 KNOTS...HEAVY RAINFALL REDUCING VISIBILITIES TO IFR
LEVELS. MEANWHILE...SHOWERS AND STRONG SOUTH WINDS WITH MVFR
CEILINGS WILL PREVAIL AHEAD OF THIS FRONT.
BEHIND THE FRONT...WIND SHIFT TO A MORE WEST OR WEST-SOUTHWEST
DIRECTION IS EXPECTED. MVFR CEILINGS EXPECTED TO LINGER DURING THE
OVERNIGHT WITH VFR CONDITIONS GRADUALLY DEVELOPING ON MONDAY.
RUA
PREV DISCUSSION... /ISSUED 313 PM CST SUN DEC 27 2015/
DISCUSSION...
SHORT TERM...TONIGHT THROUGH MONDAY
THUNDERSTORMS ARE ORGANIZING ACROSS SE TEXAS LATE THIS AFTERNOON.
LATEST SHORT TERM GUIDANCE INCLUDING HRRR HAS CONVECTIVE LINE MOVING
THROUGH SW LOUISIANA THIS EVENING AND THROUGH ACADIANA AROUND
MIDNIGHT. WILL BE MONITORING FOR ROTATING DISCRETE CELLS AHEAD OF
LINE BUT BELIEVE MOST IMPACTS WILL BE FROM PASSING SQUALL LINE LATE
THIS AFTERNOON AND TONIGHT.
WILL EXTEND WIND ADVISORY UNTIL 12Z AS TIGHT GRADIENT IS
FORECASTED TO CONTINUE AS WINDS BECOME WNW.
THE PASSAGE OF THE LOW/FRONTAL BOUNDARY WILL FINALLY BRING AN END
TO THE UNSEASONABLY WARM LATE DECEMBER WEATHER. DRIER AND MUCH
COLDER CONDITIONS ARE EXPECTED BEGINNING MONDAY. MOST OF THE
FORECAST AREA IS EXPECTED TO REMAIN IN THE 50S FOR HIGHS. WITH A
COLDER AIR MASS IN PLACE AND HIGH PRESSURE OVER THE AREA TUESDAY
MORNING...WILL NEED THE MONITOR FOR THE POTENTIAL OF FREEZING
TEMPERATURES OVER THE TEXAS LAKES REGION AND CENTRAL LOUISIANA.
LONG TERM...TUESDAY THROUGH SUNDAY
MAIN FORECAST ISSUE IN THE LONG TERM WILL BE POPS.
MODELS INDICATE A SERIES OF PROGRESSIVE UPPER TROUGHS MOVING THROUGH
THE CENTRAL U.S. THROUGH THE WEEK. A STRONG SOUTHERN JET WILL BE
OVER THE SOUTHERN PLAINS AS WELL. WHILE PWATS ARE FORECASTED TO BE
BELOW AN INCH...THERE WILL BE A GOOD MOISTURE GRADIENT OVER THE
NORTHERN GULF. THIS COMBINED WITH SUFFICIENT PACIFIC MOISTURE WILL
BRING SCATTERED SHOWERS TUESDAY NIGHT AND WEDNESDAY. THE BEST CHANCE
FOR RAIN WILL BE OVER LOWER ACADIANA. WITH THE STRONG UPPER JET
OVER THE AREA LATE IN THE WEEK...WILL HAVE LOW POPS MAINLY OVER
COASTAL AREAS. TEMPERATURES THROUGH THE WEEK WILL TREND BELOW
NORMAL AS HIGH TEMPERATURES WILL BE MOSTLY IN THE 50S.
MARINE...ONLY CHANGES TO HAZARDS WILL BE TO EXTEND SCA FOR BAYS
UNTIL 12Z. SUSTAINED FORECAST WINDS WILL BE CLOSE ENOUGH FOR GALE
WARNING OFFSHORE BEGINNING AT 00Z.
STRONG ONSHORE FLOW WILL GRADUALLY SHIFT TO THE NW AS LOW PRESSURE
MOVES THROUGH THE AKLATX TONIGHT. HIGH PRESSURE WILL BUILD
BEGINNING MONDAY AFTERNOON ALLOWING FOR WINDS/WAVES TO DIMINISH.
STRONG OFFSHORE FLOW WILL EMERGE ON WEDNESDAY AS REINFORCING SURGE
OF COLD AIR MOVES OVER THE GULF. GRADIENT WILL LIKELY FURTHER
TIGHTEN AS A LOW PRESSURE SYSTEM TRIES TO ORGANIZE OVER THE BAY OF
CAMPECHE. WITH THE GOOD GRADIENT FORECASTED TO REMAIN OVER THE AREA
THROUGH THE WEEKEND...AN EXTENDED PERIOD OF SCA CONDITIONS APPEARS
LIKELY.
&&
.PRELIMINARY POINT TEMPS/POPS...
AEX 51 55 37 57 / 100 20 10 10
LCH 48 57 39 59 / 90 10 10 10
LFT 54 60 42 60 / 90 20 10 10
BPT 45 56 39 59 / 90 10 10 10
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...WIND ADVISORY UNTIL 6 AM CST MONDAY FOR LAZ027>033-041>045-
052>055-073-074.
COASTAL FLOOD ADVISORY UNTIL 6 AM CST MONDAY FOR LAZ041-052>054-
073-074.
TX...WIND ADVISORY UNTIL 6 AM CST MONDAY FOR TXZ180-201-215-216-
259>262.
COASTAL FLOOD ADVISORY UNTIL 6 AM CST MONDAY FOR TXZ215-216.
GM...SMALL CRAFT ADVISORY FROM 6 AM TO NOON CST MONDAY FOR GMZ450-452-
455-470-472-475.
GALE WARNING UNTIL 6 AM CST MONDAY FOR GMZ450-452-455-470-472-
475.
SMALL CRAFT ADVISORY UNTIL 6 AM CST MONDAY FOR GMZ430-432-435.
&&
$$
PUBLIC...05
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1156 PM EST SUN DEC 27 2015
.AVIATION...
CONDITIONS THROUGH THE MORNING PERIOD WILL BE DEFINED BY A DRY AND
VEERING/NORTHEASTERLY FLOW...DOWNSTREAM OF AN ORGANIZING WINTER
STORM SYSTEM THAT WILL IMPACT THE REGION MONDAY AFTERNOON AND
EVENING. POCKETS OF PESKY MVFR STRATUS WILL REMAIN PROBLEMATIC EARLY
IN THE TAF PERIOD GIVEN THE FAVORABLE FLOW OFF LAKE HURON. OTHERWISE
ATTENTION IS ON THE WINTRY MIX EXPECTED TO EXPAND NORTH ACROSS SE
MICHIGAN FROM MID AFTERNOON INTO THE EVENING HOURS. FAVORABLE
ENVIRONMENT WILL EXIST TO SUPPORT PRIMARILY A COMBINATION OF SLEET
AND FREEZING RAIN DURING THE EARLY STAGES...WITH AN ACCOMPANYING
REDUCTION INTO MVFR/IFR DURING THIS TIME. SOME UNCERTAINTY EXISTS
IN BOTH THE DURATION AND END TIME...BUT GENERALLY THE GREATEST
WINDOW FOR THIS MIX OF PRECIPITATION WILL FOCUS ACROSS THE NORTHERN
TAF SITES /PTK TO MBS/ WHERE A MORE SIGNIFICANT ACCUMULATION OF
SLEET/ICE WILL BE POSSIBLE. THIS MOISTURE WILL BE ACCOMPANIED BY A
FIRM INCREASE IN EASTERLY WIND. SUSTAINED WINDS IN EXCESS OF 15
KNOTS...WITH GUSTS OF 25 TO 30 KNOTS.
AT DTW...NORTHEAST FLOW OFF LAKE HURON WILL SUPPORT MVFR STRATUS
THROUGH THE MORNING HOURS...ALTHOUGH SOME REDUCTION IN COVERAGE WILL
BE PLAUSIBLE AFTER SUNRISE. ARRIVAL OF DEEPER MOISTURE WILL LEAD TO
A PERIOD OF FREEZING RAIN/SLEET LATE MONDAY...CENTERED 19Z-23Z.
THERE REMAINS SOME UNCERTAINTY AS TO THE OVERALL DURATION OF THIS
WINTRY MIX AND POTENTIAL FOR ICE ACCUMULATION...AS THIS MOISTURE
WILL BE ACCOMPANIED BY A SURGE OF WARMER AIR. STRENGTHENING EASTERLY
FLOW /060-080/ AT THE SAME TIME...GUST POTENTIAL UP TO 30 KNOTS.
//DTW THRESHOLD PROBABILITIES...
* HIGH CONFIDENCE IN CEILING BELOW 5000 FT TONIGHT...MEDIUM MONDAY
MORNING.
* HIGH CONFIDENCE IN PRECIPITATION TYPE STARTING AS FZRA/IP AFTER
18Z MONDAY AFTERNOON...LOW IN TIMING TRANSITION TO RAIN.
* LOW CONFIDENCE IN REACHING CROSS WIND THRESHOLD FROM AN EASTERLY
WIND DIRECTION /070-080 DEG/ MONDAY AFTERNOON AND EVENING.
&&
.PREV DISCUSSION...ISSUED 910 PM EST SUN DEC 27 2015
UPDATE...
LATEST ITERATIONS OF THE RAP AND HRRR NOW REACHING INTO THE MONDAY
AFTERNOON PERIOD...AND IN CONJUCTION WITH RECENT OBSERVATIONS...
SIMPLY REINFORCE EARLIER EXPECTATIONS OF AN ONSET TIME FOR WINTRY
PRECIPITATION EXPANDING FROM SOUTH TO NORTH THROUGH THE AFTERNOON.
THIS TIMELINE DOES AFFORD A CLOSER LOOK AT THE ARRAY OF 00Z MODEL
GUIDANCE BEFORE MOVING FORWARD INTO THE WARNING/ADVISORY PHASE.
CURRENT HEADLINES PROPERLY DELINEATE CURRENT EXPECTATIONS AND THE
OVERALL MESSAGE...WHILE STILL CONVEYING SOME DEGREE OF UNCERTAINTY
/PARTICULARLY I-69 SOUTHWARD/ GIVEN THE OVERALL SENSITIVITY THIS
FORECAST CARRIES IN TERMS OF POSSIBLE MAGNITUDE AND DURATION OF
SLEET AND FREEZING RAIN BEFORE THE LOW LEVEL THERMAL PROFILE
ADVANCES ABOVE FREEZING. THEREFORE NO CHANGES ARE PLANNED TO CURRENT
HEADLINES THIS EVENING.
PREV DISCUSSION...ISSUED 403 PM EST SUN DEC 27 2015
DISCUSSION...
AS MORE 12/18Z GUIDANCE COMES IN...THINKING STILL ON TRACK FROM THE
EARLIER AFD UPDATE. THERE IS POTENTIAL FOR AROUND AN INCH OF SLEET
ACCUMULATION AND/OR 0.25 INCH OF FREEZING RAIN TO IMPACT SE MI
STARTING MONDAY AROUND 19Z...ENDING AROUND 06-09Z MONDAY NIGHT. THE
MAIN CHANGE WITH THIS FORECAST PACKAGE IS HIT HEAVIER ON SLEET
ACCUMULATION AND A LITTLE LESS ON FREEZING RAIN AS MODEL SOUNDINGS
CONTINUE TO TREND TOWARD A DEEPER COOLER BL. WINTER STORM WATCH
HEADLINES ARE OUT FOR COUNTIES NORTH OF I96. QUESTIONS REMAIN SOUTH
OF I96 AS TO WHETHER SFC TEMPS WILL STAY COLD LONG ENOUGH FOR ANY
SIGNIFICANT ACCUMULATIONS OF SLEET OR FREEZING RAIN SO WILL LEAVE
OUT OF THE WATCH AND CONTINUE TO MONITOR THERMAL TRENDS. REGARDLESS
OF WHETHER A HEADLINE IS OUT OR NOT...START TIME FOR PRECIP OVER THE
DETROIT METRO AREA LOOKS TO BE RIGHT AROUND THE EVENING COMMUTE.
BRIEF SYNOPSIS...DEEP UPPER LOW OVER TEXAS IN THE SOUTHERN STREAM OF
THE JET WILL RAPIDLY LIFT NORTHWARD ON MONDAY REACHING NORTHERN LAKE
MI BY TUESDAY MORNING. THE STRONG AND COMPACT 500MB VORT MAX WILL
LIFT NORTH THROUGH CHI BUT SEVERAL WAVES OF FORCING WILL TRACK ALONG
THE WARM FRONT UP THROUGH SOUTHERN MI LATE AFTERNOON AND EVENING
PRODUCING A MIX OF FROZEN PTYPES. A DIRECT FEED OF MOISTURE OFF THE
GOM WILL LEAD TO VERY MOIST MID LEVELS AS 850MB JET INCREASES TO
AROUND 70 KNOTS OVER THE OHIO VALLEY. THE DRY SLOT AND WARM AIR WILL
RAPIDLY LIFT NORTH OVERNIGHT WARMING THE BL RESULTING TO A
CHANGE OVER TO ALL RAIN.
PTYPE AND THERMAL PROFILES REMAIN A BIG FORECAST CHALLENGE WITH THIS
SYSTEM. FREEZING RAIN AND SLEET ARE VERY SENSITIVE TO THE THERMAL
PROFILE WITH EVEN A 1 DEGREE CHANGE AT THE SFC MAKING A LARGE
DIFFERENCE IN AMOUNT OF SLEET OR FZRA. DEWPOINTS IN THE UPPER 20S
WILL AIDE IN COOLER SFC TEMPS DURING THESE BANDS OF PRECIP AS WET
BULBING KNOCKS TEMPS BACK A COUPLE DEGREES LENDING SOME ADDITIONAL
SUPPORT TO THE FROZEN PTYPES. THE TIMING OF THE SFC FRONT AND WARM
AIR...SFC TEMPS >32F...WILL BE CRUCIAL FOR DETERMINING WHICH AREAS
GET HIT THE HARDEST. CURRENTLY IT LOOKS LIKE THE DETROIT METRO WILL
SEE A FEW HOURS OF FROZEN PTYPE BEFORE WARMER AIR LIFTS INTO THE
AREA...LIKELY BEGIN AROUND 19-21Z WHICH MAY AFFECT THE EVENING
COMMUTE SO AN ADVISORY MAY BE NEEDED FOR THOSE AREAS NOT COVERED BY
A WATCH CURRENTLY.
LASTLY...IN ADDITION TO THE PRECIP CONCERNS...EAST WINDS WILL BE
RATHER GUSTY IN THE LATE AFTERNOON/EARLY EVENING WITH GUSTS
EXCEEDING 30 MPH FOR A PERIOD. THE HIGHER WIND SPEEDS WILL POSE A
PROBLEM FOR THOSE AREAS SEEING FREEZING RAIN. ONCE THE WARM SECTOR
LIFTS INTO THE AREA AFTER MIDNIGHT...WINDS WILL RELAX THROUGH THE
REMAINDER OF THE OVERNIGHT.
THINGS QUIET DOWN A LITTLE INTO THE NEW YEAR. THE AREA WILL REMAIN
LOCKED IN A PERSISTENT LONGWAVE TROUGH DURING THIS TIME ALLOWING FOR
MULTIPLE SHORTWAVES TO RIDE THROUGH THE FLOW. THIS WILL BRING
SLIGHT CHANCES FOR SOME SNOW SHOWERS AND COOLER
WESTERLY/NORTHWESTERLY WINDS. WEDNESDAY TEMPS LOOKS TO BE THE
WARMEST THROUGH THE REMAINDER OF THE FORECAST PERIOD BEFORE TEMPS
SETTLE BACK DOWN TO AROUND NORMAL FOR THIS TIME OF YEAR.
MARINE...
FRESH NORTHERLY FLOW HAS BEEN IN PLACE TODAY OVER THE CENTRAL GREAT
LAKES AS ARCTIC HIGH PRESSURE BUILDS AGGRESSIVELY SOUTHWARD OUT OF
CANADA. SMALL CRAFT ADVISORIES REMAIN IN EFFECT FOR THE NEARSHORE
WATERS OF LAKE HURON. A STRONG WINTER STORM SYSTEM IS FORECASTED TO
LIFT NORTHWARD ALONG THE MISSISSIPPI RIVER VALLEY AND INTO THE
WESTERN GREAT LAKES MONDAY AND MONDAY NIGHT. WIDESPREAD EASTERLY
GALES REMAIN LIKELY OVER THE OPEN WATERS OF LAKE HURON AND THE
EXPOSED NEARSHORE ZONES. PEAK GUSTS OVER THE NORTHERN HALF OF LAKE
HURON ARE EXPECTED TO REACH 45 KNOT GALES MONDAY NIGHT. SIGNIFICANT
WAVE HEIGHTS WILL APPROACH 15 FEET IN THE REGION OF STRONGEST WINDS
WITH MAXIMUM WAVE HEIGHTS IN EXCESS OF 20 FEET.
HYDROLOGY...
A STRONG WINTER STORM SYSTEM WILL LIFT NORTHWARD THROUGH THE
MISSISSIPPI RIVER VALLEY AND WESTERN GREAT LAKES MONDAY AND MONDAY
NIGHT. THIS SYSTEM IS EXPECTED TO CARRY A HIGH AMOUNT OF GULF
MOISTURE WITH IT...BRINGING WIDESPREAD PRECIPITATION AMOUNTS OF .75
TO 1.0 INCH TO SOUTHEASTERN MICHIGAN. THERE REMAINS UNCERTAINTY TO
PRECIPIATION TYPE...BUT INDICATIONS ARE A SIGNIFICANT PORTION OF
PRECIPITATION MAY FALL IN THE FORM OF SLEET AND FREEZING RAIN.
ACCUMULATED ICE IS EXPECTED TO MELT QUICKLY WITH TEMPERATURES
EXPECTED TO RISE INTO THE UPPER 30S TO LOWER 40 BY TUESDAY MORNING.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...WINTER STORM WATCH FROM MONDAY AFTERNOON THROUGH LATE MONDAY NIGHT
FOR MIZ060>063-068>070.
WINTER STORM WATCH FROM MONDAY AFTERNOON THROUGH LATE MONDAY NIGHT
FOR MIZ047>049-053>055.
LAKE HURON...GALE WARNING FROM 7 AM MONDAY TO 10 AM EST TUESDAY FOR LHZ361>363-
421-441>443-462>464.
GALE WARNING FROM 10 AM MONDAY TO 4 AM EST TUESDAY FOR LHZ422.
SMALL CRAFT ADVISORY UNTIL 7 AM EST MONDAY FOR LHZ421-441>443.
LAKE ST CLAIR...GALE WARNING FROM 10 AM MONDAY TO 4 AM EST TUESDAY FOR LCZ460.
MICHIGAN WATERS OF LAKE ERIE...GALE WARNING FROM 10 AM MONDAY TO 4 AM EST TUESDAY FOR LEZ444.
&&
$$
AVIATION.....MR
UPDATE.......MR
DISCUSSION...DRK/SS
MARINE.......CB
HYDROLOGY....CB
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
235 AM CST MON DEC 28 2015
.SHORT TERM: (Through Late This Afternoon)
Issued at 235 AM CST Mon Dec 28 2015
Last slug of moderate to heavy rainfall will continue to move
through the CWA through this afternoon as the stacked low pressure
system spirals overhead. Forecast really has not changed much with
an additional 1 to 3 inches of rain expected which will likely
lead to additional flash flooding. Closely monitoring gauges and
rainfall rates this morning.
So far the winter weather has been confined to the very far
northern sections of the CWA...with some mixed precipitation, but
impacts are very minimal if any. Will keep the Winter Weather
Advisory since surface temperatures remain near freezing.
Wind continues to increase from the northeast and the current Wind
Advisory still looks like a good call with gusts to 45 MPH this
morning and early this afternoon.
CVKING
.LONG TERM: (Tonight through Sunday)
Issued at 235 AM CST Mon Dec 28 2015
Storm system quickly exits to the northeast tonight and we are
left with plenty of cloud cover. Next shortwave digs into the
Midwest Tuesday night and Wednesday with a chance of light snow
or flurries across the northern half of the CWA.
Pattern looks more like winter for the rest of the forecast with
cold temperatures. High pressure should keep conditions dry.
CVKING
&&
.AVIATION: (For the 06z TAFs through 06z Monday Night)
Issued at 1141 PM CST Sun Dec 27 2015
Strong low pressure system has moved to NE LA and is forecast to
move north northeast into central MO by about 20z. HRRR has been
pretty good in terms of positioning and precipitation trends so
have pretty much followed it for the forecast. MVFR/IFR conditions
to prevail with rain...and with a decent chance of thunderstorms
Monday morning for SUS and CPS. Thunder not out of th question for
UIN but have held off for now. Have put a couple of hours of
freezing rain at Quincy to match with forecast temperatues at 32
degrees. Strong northeast to east winds gusting to around 35 mph
will diminish and swing to the south Monday afternoon as the low
pressure center moves north of the area.
Specifics for KSTL: MVFR/IFR conditions with rain to continue.
Have included VCTS for Monday morning as HRRR shows a band of
showers/thuderstorms moving across eastern MO as the low moves
from central to northeast mo. Wind gusts to 35 mph will diminish
after 18z as the wind swings around to the south/southwest.
JPK
&&
.PRELIMINARY POINT TEMPS/POPS:
Saint Louis 50 32 38 29 / 100 20 5 10
Quincy 39 28 31 24 / 100 50 10 20
Columbia 39 28 32 24 / 100 30 5 20
Jefferson City 39 29 34 25 / 100 20 5 20
Salem 53 34 40 31 / 100 20 5 10
Farmington 53 33 39 29 / 100 10 5 10
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...Flash Flood Watch through this afternoon 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.
Wind Advisory until 1 PM CST this afternoon FOR Audrain MO-Boone
MO-Callaway MO-Knox MO-Lewis MO-Lincoln MO-Marion MO-Monroe
MO-Montgomery MO-Pike MO-Ralls MO-Shelby MO-St. Charles MO-
St. Louis City MO-St. Louis MO-Warren MO.
Winter Weather Advisory until noon CST today FOR Knox MO-Lewis
MO.
IL...Flash Flood Watch through this afternoon FOR Bond IL-Calhoun IL-
Clinton IL-Fayette IL-Greene IL-Jersey IL-Macoupin IL-
Madison IL-Marion IL-Monroe IL-Montgomery IL-Pike IL-
Randolph IL-St. Clair IL-Washington IL.
Wind Advisory until 1 PM CST this afternoon FOR Adams IL-Bond IL-
Brown IL-Calhoun IL-Clinton IL-Fayette IL-Greene IL-Jersey
IL-Macoupin IL-Madison IL-Montgomery IL-Pike IL-St. Clair
IL.
Winter Weather Advisory until noon CST today FOR Adams IL.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1154 PM CST SUN DEC 27 2015
.UPDATE:
Issued at 930 PM CST Sun Dec 27 2015
Flash Flood Watch ongoing and looks to be in good shape, with an
existing areal flood warning in effect for much of the area
already. But watch remains despite the areal flood warning
because heavier convective elements are expected to work north
overnight associated with the cold air aloft in the main storm
center, and with their heavier rainfall rate bursts, may be able
to re- initiate flash flooding in some areas. At the very least,
the steady light to moderate rain will maintain existing flooding
and slow any receding of flood waters.
Wind advisory also looks to be in good shape, with winds
increasing everywhere with the tightest gradient winds near and
north of Interstate 70/64 where gusts should reach 45mph at times.
The best chances for these winds still looks to be late tonight
and Monday morning, receding from south to north Monday morning as
the main LOW center pulls north.
Finally, Winter Wx Advisory was expanded into Adams County IL with
expected orientation of mixed pcpn from parts of northeast MO to
extend into Adams, especially the northern half of the county
north of US-24. Surface temps will edge to around freezing later
tonight and much of Monday morning, and while given recent mild
temps, it will be tough to get much accum, some more moderate
bursts of wintry pcpn may be able to get minor accums in spots.
Cold air expected to dig in and be slow to pull out Monday morning
and have extended in time all parts of this advisory until noon on
Monday.
TES
&&
.SHORT TERM: (Tonight and Monday)
Issued at 330 PM CST Sun Dec 27 2015
The last phase of the ongoing storm will impact the area over the
next 24-30 hours. The models are in good overall agreement lifting
the strong upper low currently near the Big Bend area of TX to the
northeast and through the MS Valley with the system becoming
vertically stacked in the process. The lifting upper low, coupled
ULJs, and a strong southerly and eventually cyclonically curved LLJ
will contribute to strong large scale ascent spreading back
northward across the entire area tonight, and then shifting to
the east of the CWA by late Monday afternoon.
Three items to address in this final phase. First the ongoing
historic and deadly heavy rain and flood event. We can`t convey
strongly enough - Don`t drive into water on flooded roads. Already
11 known fatalities in MO/IL. Thus far we have seen a band of
5-7+ inches of rain from southwest MO through the St. Louis area
into south central IL. The main rain band has shifted to the south
today across southern IL and southern MO, and the overall
intensity and rain rates has diminished as expected. This band and
additional rain will spread back northward tonight as the storm
system lifts northeast with rainfall rates increasing. Highest
rainfall rates and amounts should be across the southern half of
MO and IL where embedded thunder will enhance the rates as well,
primarily from 06-18z. The rain intensity and coverage should
wind down on Monday afternoon as the system lifts to the north and
the initial occluded/cold front passes to the east. Current
expectations are an Additional 2-4 inches of rain before it ends
by 00Z Tuesday.
Second item is the threat of wintry precipitation tonight into
early Monday morning. We have been watching this closely the last
few days, and now a larger number of models are suggesting that
surface temps will drop into the 31-32F range overnight across a
very small part of far northeast MO (Knox and Lewis Co). Soundings
also suggest some sleet potential. This seems reasonable and have
decided to issue a winter weather advisory for this area for light
accumulations.
The third item is wind. We already have gusty northeast winds and
they will increase this evening as the pressure gradient tightens
in response to the lifting surface low and the high pressure
system to our north. I have issued a wind advisory for the region
along and north of I-70 beginning this evening and continuing into
early Monday afternoon.
Glass
.LONG TERM: (Monday Night through Next Sunday)
Issued at 330 PM CST Sun Dec 27 2015
The system will continue to depart on Monday night with the
secondary cold front moving through the area and surface winds
shifting to the west. There remains a chance of light precipitation
in the cyclonic flow in the wake of the low on Monday evening, and
some of this could be light snow in central and northeast MO.
Little if any measurable precipitation is expected.
Another short wave trof moves through the area late Tuesday night
into Wednesday. There is limited moisture with this system and any
precipitation should be primarily snow, however the threat is
quite low in our area at this time.
A big pattern change will occur by the end of the upcoming week
and into next weekend with split flow featuring a rex block in the
western U.S. and a deep upper trof in eastern NOAM. This pattern
favors seasonably cold temps.
Glass
&&
.AVIATION: (For the 06z TAFs through 06z Monday Night)
Issued at 1141 PM CST Sun Dec 27 2015
Strong low pressure system has moved to NE LA and is forecast to
move north northeast into central MO by about 20z. HRRR has been
pretty good in terms of positioning and precipitation trends so
have pretty much followed it for the forecast. MVFR/IFR conditions
to prevail with rain...and with a decent chance of thunderstorms
Monday morning for SUS and CPS. Thunder not out of th question for
UIN but have held off for now. Have put a couple of hours of
freezing rain at Quincy to match with forecast temperatues at 32
degrees. Strong northeast to east winds gusting to around 35 mph
will diminish and swing to the south Monday afternoon as the low
pressure center moves north of the area.
Specifics for KSTL: MVFR/IFR conditions with rain to continue.
Have included VCTS for Monday morning as HRRR shows a band of
showers/thuderstorms moving across eastern MO as the low moves
from central to northeast mo. Wind gusts to 35 mph will diminish
after 18z as the wind swings around to the south/southwest.
JPK
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...Flash Flood Watch through Monday afternoon 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.
Wind Advisory until 1 PM CST Monday FOR Audrain MO-Boone MO-
Callaway MO-Knox MO-Lewis MO-Lincoln MO-Marion MO-Monroe MO-
Montgomery MO-Pike MO-Ralls MO-Shelby MO-St. Charles MO-St.
Louis City MO-St. Louis MO-Warren MO.
Winter Weather Advisory until noon CST Monday FOR Knox MO-Lewis
MO.
IL...Flash Flood Watch through Monday afternoon FOR Bond IL-Calhoun
IL-Clinton IL-Fayette IL-Greene IL-Jersey IL-Macoupin IL-
Madison IL-Marion IL-Monroe IL-Montgomery IL-Pike IL-
Randolph IL-St. Clair IL-Washington IL.
Wind Advisory until 1 PM CST Monday FOR Adams IL-Bond IL-Brown
IL-Calhoun IL-Clinton IL-Fayette IL-Greene IL-Jersey IL-
Macoupin IL-Madison IL-Montgomery IL-Pike IL-St. Clair IL.
Winter Weather Advisory until noon CST Monday FOR Adams IL.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
National Weather Service Kansas City/Pleasant Hill MO
1118 PM CST SUN DEC 27 2015
.UPDATE...
Issued at 800 PM CST SUN DEC 27 2015
Taking a look at 00Z sounding data shows a very pronounced warm nose
over southern Missouri, but lower in the atmosphere than models had
predicted it to be (peaks out at 850 hPa instead of 800 hPa). Wind
flow lower in the atmosphere favors this warm air to spread more
north-northeast instead of the north-northwest trajectories further
up aloft. This could delay the onset of warm air aloft over western
MO and northeast KS, so that the transition from snow and sleet over
to freezing rain may not occur across the I-35 corridor until 12Z or
later, after several hours of mostly snow and a little sleet could
accumulate to several inches. RAP has been hinting at this colder
possibility and new NAM trickling in seems to be trending much colder
aloft as well. Will likely need to increase snow/sleet amounts quite
a bit for the I-35 corridor and points northwest, where 3" to 8" of
snow isn`t out of the realm of possibility. Further complicating
things is the fact that precipitation may obtain a convective element
toward sunrise, right as the precipitation changeover is occurring.
If this leads to thundersnow, as could happen just northwest of KC,
this could lead to snow rates of 2" per hour or greater, but if it`s
falling as sleet (or even graupel/hail) that will cut back on snow
amounts quite a bit. Will continue to watch model data trickle in but
a new forecast to increase snow amounts near and northwest of I-35
will likely be coming out shortly.
&&
.SHORT TERM...(This Evening through Tuesday Afternoon)
Issued at 331 PM CST SUN DEC 27 2015
A complex winter storm is still on track to impact the area this
evening through Monday night as low pressure lifts out the southern
High Plains and into the forecast area. Model agreement is much
higher on the overall track of the system; however, there are still
significant differences in the temperature profile from the surface
through the depth of the column, which impacts precipitation type
and result in still a range of forecast possibilities, especially
over the KC metro area.
Rain showers will continue to lift northward tonight in response to
the ejecting system, reaching the KC area between 9 PM and midnight,
and the northern CWA border by 3 AM. Surface temperatures currently
range from around 30 degrees in northwest MO to the mid 30s across
central MO, and will likely change little due to the battle between
strong cold air advection and progressively warming temperatures
aloft. As a result, some freezing rain will become possible as
showers move over subfreezing temperatures, and could initially mix
with sleet as the column saturates. Precipitation will eventually
meet and cross the freezing line aloft, resulting in more sleet and
perhaps some snow on the northern border of the precip shield as it
lifts northward early Monday morning. The warm nose centered around
800 hPa will continue to surge northward; however, resulting in
mixed precipitation and at least a short period of freezing rain
across much of the northwestern half to third of the CWA. The NAM is
by far the most aggressive solution for freezing rain accumulation
and appears to be an outlier with its nearly +8 to +9 warm nose, but
if it verifies, could mean quite a bit more ice than is currently
forecast mainly from Kansas City northwestward. In contrast, the GFS
and EC do not feature as strong of a warm nose and keep the surface
freezing line closer to the freezing line aloft -- making for a more
linear solution of rain in the warm sector and sleet/snow in the
cold sector, and lower ice amounts than the forecast currently
indicates especially for KC. Conceptually, it appears that the
highest threat for ice accumulation will be in areas that are
already several degrees below freezing this afternoon, which is
mainly the far northwest side of the KC metro up to the St. Joseph
area, before colder temperatures aloft reduce the probability of
liquid precipitation.
All models show some surface warming as the low lifts up, bringing
temperatures to or slightly above 32 degrees by late Monday morning,
which would end the freezing rain threat before the changeover to
snow occurs Monday afternoon. Even the NAM has a period of all rain
for all but extreme northwest and northern MO after sunrise Monday,
melting some or all of the ice accumulation and possibly reducing
some of the travel impacts for the late morning and early afternoon.
Regardless, liquid precipitation will gradually transition to snow
from west to east as the surface low moves east of the forecast
area, and should bring quite a bit of snow to far northwest MO where
the changeover will happen earliest and be coincident with the most
precipitation equivalent. Almost 10 inches of storm total snow is
possible in our northwest corner where the deformation zone will be
best defined, tapering off very quickly to less than 4 inches in St.
Joseph and to an inch or less from KC to Kirksville where the
transition will occur after the precipitation rates have begun to
taper off.
Winds will also be extremely strong on the northeast side of the
surface low tonight into tomorrow morning, likely reaching advisory
criteria throughout the entire forecast area after 03z tonight, and
further complicating ice accumulation should it occur late tonight
through Monday morning. Based on this forecast, have opted to trim
off the southeast side of the winter storm warning where surface
temperatures may stay too warm, and continue it elsewhere. The
southeast gradient of the warning may not reach true warning
criteria, but potential for significant sleet accumulation and the
combination of strong winds and freezing rain during the early
morning hours, especially on a work/holiday travel day, warranted a
continuation of the warning in those areas. A wind advisory will be
issued elsewhere.
A full transition to snow is expected before the system fully exits
the area, giving almost the entire CWA a light dusting as it
departs. All snow should be out of the region by Tuesday morning.
.LONG TERM...(Tuesday Evening through Sunday)
Issued at 331 PM CST SUN DEC 27 2015
On the heels of the winter storm in the early week, an embedded
shortwave ejecting off of a broad, weakening trough over the western
CONUS may produce additional wintry activity by Wednesday. The
uncertainties with this feature are the availability of moisture in
the wake of the exiting storm system along with the speed at which
it crosses through the region ahead of a building ridge to the west.
Should any precipitation develop, the thermal profile will be well
supportive of all snow. The question that will need to be addressed
is how much, all dependent on moisture availability. Areas that look
to be impacted as of now include northeast Kansas and northwest
Missouri, coincident with areas to be impacted on Monday with the
winter storm system.
Beyond this activity, the active weather pattern should subside
through the remainder of the week as a building ridge will maintain
dry conditions heading into the weekend. The cold air mass will
remain firmly in place with afternoon highs likely remaining below
freezing for the remainder of the week, with overnight lows dipping
into the teens for most of the CWA, and single digits for northwest
Missouri. Temperatures should recover a bit late into the weekend as
the building ridge moves eastward.
&&
.AVIATION...(For the 06Z TAFS through 06Z Monday Night)
Issued at 1120 PM CST SUN DEC 27 2015
Current radar...observations...and models showing that precipitation
has overspread all areas except KSTJ...currently falling as -FZRA.
With the warm air aloft as measured by balloons still moving up from
KSGF and further south...expect the transition to ice pellets and
snow to occur overnight. As the storm system tracks northeast from
Oklahoma/Arkansas and cold air in lower levels continues to keep
surface at or below freezing...the precipitation will continue as
sleet and then snow further north and west.
&&
.EAX Watches/Warnings/Advisories...
KS...Wind Advisory until noon CST Monday for KSZ060.
Winter Weather Advisory until 9 PM CST Monday for KSZ060.
Winter Storm Warning until 9 PM CST Monday for KSZ025-057-
102>105.
MO...Wind Advisory until noon CST Monday for MOZ024-025-031>033-
038>040-043>046-053-054.
Winter Weather Advisory until 9 PM CST Monday for MOZ024-025-031-
038-043.
Winter Storm Warning until 9 PM CST Monday for MOZ001>008-
011>017-020>023-028>030-037.
&&
$$
UPDATE...Hawblitzel
SHORT TERM...Laflin
LONG TERM...Welsh
AVIATION...Adolphson
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
339 AM CST MON DEC 28 2015
.SYNOPSIS...
ISSUED AT 335 AM CST MON DEC 28 2015
HIGHLY ANOMALOUS UPPER LOW LOCATED S OF KFWD PROGRESSING NEWD AS
EXPECTED WITH CONVECTION REDEVELOPING IN THE WCB AHEAD OF THE
LOW. ALSO AS EXPECTED...MOISTURE ADVECTION IN THE WCB IS
IMPRESSIVE AND IN SOME CASES UNPRECEDENTED IN THE SERN STATES AND
PORTIONS OF THE LOWER MS VALLEY. CCB ALSO BECOMING BETTER DEFINED
THIS MORNING AS EVIDENCED BY MOISTURE TRANSPORT VECTORS ON THE
290K SFC. DOWNSTREAM RIDGE HAS DEVELOPED FROM THE NRN PLAINS INTO
THE MIDWEST SHORTENING THE TROUGH TO RIDGE WAVELENGTH AND WITH
THE IMPRESSIVE DYNAMICS ONGOING ACROSS TX AND THE PREVIOUSLY
MENTIONED WCB CHARACTERISTICS...NO SURPRISE THAT SFC PRESSURES
ARE NOW FALLING AT GREATER THAN 6MB/3HR ACROSS NWRN AR. ON THE
WRN/NRN SIDE OF THE LOW...PW VALUES AT OR BELOW DAILY LOWS ARE
NOTED HERE AT LBF AND ALSO OAX DEPICTING THE STRONG GRADIENT OF
MOISTURE THE SYSTEM WILL HAVE TO WORK WITH. MID AND UPPER LEVEL
CLOUD SHIELD HOLDING TEMPS UP MOST AREAS OF THE LBF CWA EARLY
THIS MORNING...BUT IN PARTS OF THE PANHANDLE WHERE SKIES ARE CLR
TEMPS HAVE FALLEN QUICKLY. ON RADAR ECHOES INCREASING ACROSS SRN
NEB BUT...DESPITE ECHOES IN WRN KS MOST OF THE NIGHT...NO PRECIP
REACHING THE GROUND AND THIS MAKES SENSE BASED ON THE VERY DRY
ATMOSPHERE.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 335 AM CST MON DEC 28 2015
DIFFICULT FCST TODAY WITH RESPECT TO THE AMOUNT OF MOISTURE THAT
WORKS AROUND THE NRN AND WRN SIDE OF THE AFOREMENTIONED UPPER LOW
AS IT MOVES NEWD INTO THE MIDWEST. A DEEP DRY LAYER WILL HAVE TO
BE OVERCOME BEFORE SNOW CAN MAKE IT DOWN TO THE SFC WHICH WILL
EVENTUALLY HAPPEN IN NORTH CENTRAL NEB AFTER NOON BUT THE FORCING
IN THAT AREA IS BROAD AND RELATED TO ISENTROPIC LIFT AS WARM AIR
GETS WRAPPED AROUND THE MATURE SYSTEM. MODELS SIMILAR IN TRACKING
THE MID LEVEL WARM SECLUSION QUICKLY INTO IL BY 00Z TUE AND
ISENTROPIC LIFT IN NC NEB TRANSITIONS QUICKLY TO DOWNGLIDE
THEREAFTER. THIS MEANS THERE WILL BE A NARROW WINDOW OF
OPPORTUNITY WITH WHICH THE SYSTEM WILL BE ABLE TO DEVELOP
SNOWFALL THIS FAR WEST. WHILE THERE IS SOME INDICATION OF MID
LEVEL FRONTOGENESIS WHICH WOULD SERVE TO ENHANCE LIFT...BEST NEG
EPV /WHICH WOULD ENHANCE LIFT FURTHER/ APPEARS TO BE LOCATED
FURTHER EAST. HAVE ULTIMATELY TRIMMED BACK QPF/SNOW AMOUNTS IN
THE LOCATIONS OF NC NEB WHERE CONFIDENCE IS HIGHEST FOR
ACCUMULATING SNOW. 1-2 INCHES IN PORTIONS OF HOLT/BOYD/KEYA
PAHA/ROCK COUNTIES FOR THE MOST PART...AND COULD APPROACH 3
INCHES IN PORTIONS OF HOLT/BOYD COUNTIES. THIS WITH SNOW TO
LIQUID RATIOS IN THE 13 OR 14 TO 1 RANGE WITH A LARGE SATURATED
ISOTHERMAL LAYER IN THE -8 TO -9 C RANGE FOR KONL.
CLOUD COVER MAY THIN SOME ON THE SWRN FRINGE OF THE SYSTEM
OVERNIGHT AND WOULD EXPECT TEMPS TO DROP QUICKLY THERE...THOUGH
AS IS TYPICAL CLOUD COVER WILL DICTATE LOWS. WINDS THROUGHOUT THE
DURATION OF THIS STORM SHOULD BE LESS THAN 15MPH IN MOST CASES.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 335 AM CST MON DEC 28 2015
HOLDING ONTO SOME COLD AIR FOR THE LAST FEW DAYS OF 2015. HOWEVER
A WARM UP TO START 2016 IS IN STORE. A PIECE OF THE MAIN LOW
PRESSURE SYSTEM ACROSS THE GREAT LAKES WILL DRIFT ACROSS THE NRN
PLAINS EARLY TUESDAY. LINGERING LIGHT SNOW ACROSS N CENTRAL COULD
YIELD SOME MEASURABLE SNOW TUES MORNING...MORE LIKELY FLURRIES.
NEXT SYSTEM TO DIG ACROSS THE 4 CORNERS REGION TUESDAY THEN PUSH
EAST ACROSS THE SRN ROCKIES THEN LIFT NORTHEAST. SYSTEM REMAINS
WELL SE OF THE FORECAST AREA AND MODELS IN GOOD AGREEMENT. THE
YEAR ENDS ON THE DRY AND COLD SIDE...HIGHS IN THE 10S AND 20S.
EASILY 10 TO 15 DEGREES BELOW NORMAL. THIS ALL CHANGES WITH THE
ARRIVAL OF A WESTERN RIDGE BY FRIDAY. MODELS WARM 850 MB TEMPS
RANGING FROM 0 TO PLUS 5C FOR THE WEEKEND. THE RESULTING HIGHS OF
30S AND 40S WHICH IS SUPPORTED BY MOS GUIDANCE INCREASES FORECAST
CONFIDENCE. LINGERING AREAS WITH A SNOW PACK COULD HOLD HIGHS IN
THE 20S...HOWEVER WITH MOSTLY SUNNY SKIES WILL SIDE WITH THE
WARMER GUIDANCE FOR NOW.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1125 PM CST SUN DEC 27 2015
THE UPPER LOW ACROSS TEXAS MOVES NORTHEAST OVERNIGHT THROUGH
MONDAY EVENING. THE RAP INDICATES MVFR CIGS AND LIGHT SNOW ALONG
AND EAST OF HIGHWAY 281 MONDAY. VFR IS EXPECTED TO DEVELOP IN
THIS AREA LATE MONDAY EVENING...AOA 06Z. ELSEWHERE...VFR WITH MID
LEVEL CLOUDINESS NEAR 15 KFT OVERNIGHT THROUGH MONDAY EVENING.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...STOPPKOTTE
SHORT TERM...STOPPKOTTE
LONG TERM...MASEK
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1126 PM CST SUN DEC 27 2015
.UPDATE...
ISSUED AT 850 PM CST SUN DEC 27 2015
NO CHANGES THIS EVENING TO THE PREVIOUS THINKING...WILL LET THE
HEADLINES STAY AS IS.
SOME OBSERVATIONS FROM THE 00Z UPPER AIR DATA. THE KOAX SOUNDING
ONLY HAD A PW OF 0.08 INCHES...WHICH WAS DOWN FROM 0.20 AT 12Z.
MOISTURE WAS MUCH BETTER TO THE SOUTH THOUGH...WITH PW AT KTOP AT
0.53 INCHES. WILL LIKELY TWEAK DOWN THE QPF JUST A BIT 06Z TO 12Z
TONIGHT IN OUR SRN COUNTIES WITH THE EVENING UPDATE.
12 HOUR HEIGHT FALLS AT 500 MB WERE HIGHEST...ABOUT 150 METERS...
JUST NORTHEAST OF KDRT IN TX. KICKER SHORTWAVE CONTINUED TO CRASH
INTO THE WRN UNITED STATES...WITH HEIGHT FALLS OF UP TO 110 METERS.
LATEST WATER VAPOR LOOP SHOWED SOME NWD MOVEMENT OF THE MID LEVEL
CLOSED CIRCULATION OVER TX. THE GENERAL CONSENSUS OF THE LATEST
AVAILABLE MODEL DATA...ECMWF/GFS/NAM/SREF/HRRR BRINGS THE CENTER
OF THE CIRCULATION TO SWRN MO BY 18Z MONDAY...THEN TO WRN IL BY
00Z TUE.
00Z NAM SHOWED A LOT LESS SNOW THAN OTHER MODELS...AND WAS NOT
PREFERRED. 00Z EXPERIMENTAL HRRR SHOWED QPF OF 0.25 TO 0.55 INCHES
ACROSS MUCH OF SERN NE AND WRN IA 12Z TO 18Z MON (0.35 TO 0.45 IN
THE OMAHA METRO). THE QPF FROM THAT SAME MODEL 18Z MON TO 00Z TUE
VARIED FROM 0.10 IN OUR FAR WRN COUNTIES TO AROUND 0.80 JUST EAST
OF POTTAWATTAMIE COUNTY IA (WITH AROUND 0.20 FOR OMAHA METRO).
&&
.SHORT TERM...(TONIGHT THROUGH WEDNESDAY)
ISSUED AT 250 PM CST SUN DEC 27 2015
TRACK AND INTENSITY OF SOUTHERN PLAINS STORM SYSTEM AND RESULTANT
SNOWFALL WILL BE THE MAIN FORECAST CHALLENGE AS THE SYSTEM LIFTS
ACROSS THE LOWER MISSOURI VALLEY ON MONDAY.
THE WINTER STORM WATCH THAT COVERED THE AREA HAS BEEN UPGRADED TO
A WINTER STORM WARNING FOR ALL BUT A FEW COUNTIES IN EXTREME
NORTHEAST NEBRASKA WHERE A WINTER WEATHER ADVISORY WILL BE IN
EFFECT ON MONDAY. THE MAJORITY OF MODELS THIS MORNING CONTINUE TO
SHOW A MAJOR WINTER STORM MOVING ACROSS THE FORECAST AREA STARTING
LATE TONIGHT AND EXTENDING INTO MONDAY NIGHT. GOOD UPPER SUPPORT
AND ABUNDANT MOISTURE WILL RESULT IN HEAVY SNOW AND GUSTY NORTH
WINDS FOR THE AREA AND WILL CREATE HAZARDOUS TRAVEL CONDITIONS
FOR THOSE FOLKS HEADING HOME AFTER THE CHRISTMAS HOLIDAY WEEKEND.
PRIMARY AXIS OF HEAVY SNOW LOOKS TO BE ORIENTED RIGHT ACROSS
EASTERN NEBRASKA INTO NORTHWEST IOWA ON MONDAY WITH PERIODS OF
SLEET AT TIMES FROM PARTS OF SOUTHWEST IOWA INTO EXTREME SOUTHEAST
NEBRASKA. THE STORM SYSTEM SHOULD MOVE ACROSS THE REGION RATHER
QUICKLY...RACING FROM SOUTHEAST OKLAHOMA ON MONDAY MORNING TO
SOUTHERN WISCONSIN BY LATE MONDAY NIGHT. DRIER MID LEVEL AIR MAY
HINDER THE APPROACHING MOISTURE FOR A TIME LATER TONIGHT BUT THE
ATMOSPHERE IS EXPECTED TO SATURATE QUICKLY AS THE STORM GETS
CLOSER TO THE AREA. MAJORITY OF SNOW ACCUMULATION WILL BE OVER BY
MONDAY EVENING ALTHOUGH LINGERING PERIODS OF LIGHT SNOW WILL
CONTINUE THROUGH MONDAY NIGHT. ANOTHER UPPER TROUGH COMING ACROSS
THE REGION TUESDAY NIGHT MAY ALSO TRIGGER SOME LIGHT SNOW IN FAR
SOUTHEAST NEBRASKA AND SOUTHWEST IOWA.
.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 250 PM CST SUN DEC 27 2015
LESS ACTIVE WEATHER BUT REMAINING COLD THROUGH THE PERIOD AS MEAN
TROUGH STAYS OVER THE EASTERN THIRD OF THE NATION AND AREA
CONTINUES UNDER THE INFLUENCE OF NORTHWEST FLOW. TODAYS MODELS
ALSO SHOW LESS RIDGE DEVELOPMENT IN THE WEST COMPARED TO
YESTERDAY.
&&
.AVIATION...(06Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 1125 PM CST SUN DEC 27 2015
CLOUDS WILL THICKEN/LOWER OVERNIGHT. CONDITIONS WILL DETERIORATE
RAPIDLY AFTER 11Z OR 12Z BASED ON CURRENT THINKING...WITH LIFR
CONDITIONS LIKELY DEVELOPING IN THE MORNING AT KOMA AND KLNK WITH
SNOW. WINDS WILL ALSO BE ON THE INCREASE. CONDITIONS SHOULD
DETERIORATE AT KOFK AS WELL...BUT A BIT LATER AND WITH CONDITIONS
MAYBE NOT QUITE AS LOW FOR CIGS. LOOK FOR A GRADUAL IMPROVEMENT
DURING THE EVENING AS SNOW MOVES OUT.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...WINTER STORM WARNING FROM 6 AM MONDAY TO 6 AM CST TUESDAY FOR
NEZ012-015-017-018-031>034-042>045-050>053-065>067-078.
WINTER STORM WARNING FROM 3 AM MONDAY TO MIDNIGHT CST MONDAY
NIGHT FOR NEZ068-088>093.
WINTER WEATHER ADVISORY FROM 6 AM MONDAY TO 6 AM CST TUESDAY FOR
NEZ011-016-030.
IA...WINTER STORM WARNING FROM 6 AM MONDAY TO 6 AM CST TUESDAY FOR
IAZ043-055-056-069-079.
WINTER STORM WARNING FROM 3 AM MONDAY TO MIDNIGHT CST MONDAY
NIGHT FOR IAZ080-090-091.
&&
$$
UPDATE...MILLER
SHORT TERM...FOBERT
LONG TERM...FOBERT
AVIATION...MILLER
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
1125 PM CST SUN DEC 27 2015
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 252 PM CST SUN DEC 27 2015
STRONG UPPER LEVEL LOW CENTERED NEAR EL PASO TX THIS AFTERNOON.
MODELS ARE NOW IN GOOD AGREEMENT ON THE TRACK OF THE UPPER LOW
THROUGH MISSOURI INTO WISCONSIN BY MONDAY NIGHT. THERE IS ALWAYS THE
POTENTIAL FOR A WOBBLE DUE TO CONVECTION THAT WILL BE
OCCURRING...BUT FAIRLY CONFIDENT IN THE PROJECTED TRACK. THIS TRACK
WOULD MEAN MOST OF OUR FORECAST AREA OF WESTERN AND NORTH CENTRAL
NEBRASKA WILL MISS THE SNOW. THE EXCEPTION WILL BE FAR EASTERN
PORTIONS OF NORTH CENTRAL NEBRASKA...WHERE A WEAKENING DEFORMATION
BAND OF SNOW SHOULD PUSH IN FROM THE EAST/SOUTHEAST DURING THE
AFTERNOON. AGAIN...WILL MONITOR THE SYSTEM CLOSELY AND IF IT WOULD
WOBBLE A BIT WEST OF THE FORECASTED TRACK...SNOW COULD SPREAD
FARTHER WEST INTO OUR AREA.
AS FAR AS SNOW AMOUNTS...GENERALLY EXPECTING AROUND 4 INCHES TOTAL
ACCUMULATION ACROSS FAR EASTERN WHEELER...HOLT AND BOYD COUNTIES.
ONE POSITIVE FOR SNOW ACCUMULATION IS THE FAIRLY HIGH SNOW TO LIQUID
RATIOS EXPECTED DUE TO COLD TEMPERATURES BOTH AT THE SURFACE AND
ALOFT. SNOWFALL TOTALS WILL QUICKLY DIMINISH WEST OF THE
AFOREMENTIONED AREAS...AS CROSS SECTIONS INDICATE A DEEP DRY LAYER
IN THE MID LEVELS OF THE ATMOSPHERE BY THE TIME YOU GET TO VALENTINE
SOUTH THROUGH NORTH PLATTE. WILL MAINTAIN THE SLIGHT CHANCE FOR
THESE AREAS JUST IN CASE A FARTHER WEST TRACK. WILL NOT ISSUE AN
ADVISORY FOR THE SNOW AT THIS TIME IN BOYD..HOLT AND WHEELER
COUNTIES..AS ACCUMULATIONS LOOK TO BE MARGINAL...AND WINDS NOT
REALLY THAT STRONG SO MINIMAL BLOWING SNOW IF ANY.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 252 PM CST SUN DEC 27 2015
MEDIUM RANGE OUTPUT FROM THE MORNING MODEL RUNS SHOW THAT THEY HAVE
COME TOGETHER WITH THE TRACK OF THE CENTER OF THE MID-LEVEL CYCLONE.
THE GEMNH...NAM12 FROM THE 12Z CYCLE AND 00Z ECMWF SHOW THE
PRECIPITATION SHIELD OF 0.1 INCH EXTENDING INTO BOYD...HOLT...
GREELEY AND WHEELER COUNTIES. THE FORECAST SOUNDING FROM THE NAM12
INDICATE THE SNOW ALREADY IN PROGRESS MONDAY EVENING WHILE THE GFS40
SOUNDINGS INDICATE IT STARTING ABOUT 00Z. BOTH SETS OF FORECAST
SOUNDINGS SHOW LOW DEWPOINT DEPRESSIONS INTO THE DENDRITIC GROWTH
ZONE AND BEYOND WITH THE SATURATED ISOTHERMAL LAYER IN THE 0C TO -5C
TEMPERATURE LAYER. THIS WOULD FAVOR FAIRLY EFFICIENT PRODUCTION OF
LARGER SNOWFLAKES GIVING A SNOW TO LIQUID RATIO OF A LITTLE ABOVE
13:1...POSSIBLY AS HIGH AS 17:1 BUT MORE LIKELY 15:1 MORE OR LESS.
BY 12-18Z...DRIER AIR IN THE GROWTH ZONE WILL PROBABLY BRING AN END
TO ANY PRECIPITATION BY LATE MORNING TO EARLY AFTERNOON.
AFTER THIS SYSTEM...LITTLE OR NO PRECIPITATION IS EXPECTED INTO NEXT
WEEKEND AND TEMPERATURES WILL STAY BELOW 30 UNTIL FRIDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1125 PM CST SUN DEC 27 2015
THE UPPER LOW ACROSS TEXAS MOVES NORTHEAST OVERNIGHT THROUGH
MONDAY EVENING. THE RAP INDICATES MVFR CIGS AND LIGHT SNOW ALONG
AND EAST OF HIGHWAY 281 MONDAY. VFR IS EXPECTED TO DEVELOP IN
THIS AREA LATE MONDAY EVENING...AOA 06Z. ELSEWHERE...VFR WITH MID
LEVEL CLOUDINESS NEAR 15 KFT OVERNIGHT THROUGH MONDAY EVENING.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...TAYLOR
LONG TERM...SPRINGER
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS RALEIGH NC
300 AM MON DEC 28 2015
.SYNOPSIS... A STRONG SUB-TROPICAL RIDGE OF HIGH PRESSURE WILL
PERSIST OFF THE SOUTHEAST COAST FOR THE NEXT FEW DAYS. A COLD FRONT
WILL DROP SOUTH THROUGH VIRGINIA TONIGHT AND INTO NORTH CAROLINA ON
MONDAY. A STRONG STORM SYSTEM WILL DEVELOP IN THE LOWER MISSISSIPPI
VALLEY ON MONDAY AND MOVE INTO THE EASTERN GREAT LAKES ON TUESDAY.
&&
.NEAR TERM /THROUGH MONDAY NIGHT/...
AS OF 1000 PM SUNDAY...
NO ADDITIONAL MAJOR CHANGES TO THE FORECAST TONIGHT. THE COLD FRONT
THAT WILL MOVE IN LATER TONIGHT IS CURRENTLY PUSHING THROUGH THE MID-
ATLANTIC STATES...WITH NORTHERLY WINDS APPROACHING CENTRAL VA. HIGH
CLOUDS ARE PLENTIFUL ACROSS THE CAROLINAS...WHICH MAY MAKE IT HARD
FOR FOG TO DEVELOP HERE IN CENTRAL NC...ESPECIALLY IN THE WESTERN
PIEDMONT. HOWEVER... THE HRRR STILL SHOWS A BRIEF PERIOD OF FOG OR
VERY LOW STRATUS IMMEDIATELY AHEAD OF THE FRONT AS WINDS
DIMINISH...MORE TOWARD 09-12Z. -22
PREVIOUS FORECAST... THE ANOMALOUS WARM SECTOR IN PLACE THIS PAST
WEEK WILL PERSIST OVER THE MAJORITY OF CENTRAL NC NIGHT...EXCEPT FOR
THE NORTHERN PIEDMONT AND NE COASTAL PLAIN LATER TONIGHT WHEN A BACK-
DOOR COLD FRONT PROGRESSES SOUTHWARD FROM VA INTO NC ~08-12Z. IN THE
NORTH...LOWS WILL PRIMARILY BE A FUNCTION OF COLD ADVECTION IN THE
WAKE OF THE COLD FRONTAL PASSAGE LATE TONIGHT (08-12Z MON)...PERHAPS
AIDED BY EVAPORATIVE COOLING ATTENDANT LIGHT RAIN AS SOUTH/SE LOW-
LEVEL FLOW (925-850 MB )ADVECTS A WARM/MOIST AIRMASS NORTHWARD ATOP
THE SHALLOW COLDER AIRMASS ADVECTING SOUTHWARD. IN THE SOUTH...LOW
TEMPS WILL BE DRIVEN BY RADIATIONAL COOLING (MAGNITUDE OF WHICH WILL
DEPEND ON CLOUD COVER). -VINCENT
AS THE FRONT DROPS SOUTH ON MONDAY...AREAS OF RAIN WILL LIKELY
EXPAND IN THE DEVELOPING OVER RUNNING PATTERN WHICH WILL LOCK IN
CLOUDS AND CONTRIBUTE ADDITIONAL COOLING. TEMPERATURES ACROSS THE
NORTHERN PIEDMONT AND NORTHERN COASTAL PLAIN WILL FALL INTO THE
UPPER 40S BY LATE IN THE DAY WITH THE COLD FRONT PUSHING THROUGH ALL
OF CENTRAL NC BY NIGHTFALL. THE COOLER AIR MASS WILL BE SLOWER TO
ARRIVE ACROSS THE SOUTHERN PIEDMONT AND SANDHILLS BY THE CLOUDS AND
PRECIPITATION WILL LIMIT THE DIURNAL TEMPERATURE RECOVERY.
NWP GUIDANCE GUIDANCE HAS BEEN CONSISTENT IN QUICKLY SCOURING THE
LOW LEVEL COLD AIR MASS ON MONDAY NIGHT WITH THE WARM FRONT PUSHING
NORTH INTO THE DC AREA BY DAYBREAK TUESDAY. PAST EXPERIENCE SUGGESTS
THAT THIS IS LIKELY TOO FAST AND HAVE SLOWED THE PASSAGE OF THE WARM
FRONT BY 2-4 HOURS WHICH STILL MAY NOT BE SUFFICIENT IF THE HYBRID
CAD EVENT LOCKS IN. STILL IT WILL BE A CLOUDY AND DAMP NIGHT WITH
PERIODS OF RAIN AND TEMPERATURES STEADY AND THEN BEGINNING TO RISE
TOWARD DAYBREAK. -BLAES
&&
.SHORT TERM /TUESDAY AND TUESDAY NIGHT/...
AS OF 230 PM SUNDAY...
MODELS HAVE CONSISTENTLY FORECAST THE CAD TO SCOUR RAPIDLY LATE
MONDAY NIGHT AHEAD OF AN APPROACHING WEAK COLD FRONT. ANY LINGERING
LIGHT RAIN MONDAY NIGHT WILL TAPER TO SCATTERED SHOWERS EARLY
TUESDAY AS LOW LEVEL FLOW VEERS AROUND TO SOUTH AND SOUTHWEST...
ENDING THE ISENTROPIC LIFT AND INITIATING STRONG WARM AIR ADVECTION.
WOULD EXPECT DENSER CLOUD COVERAGE AND POSSIBLY SOME LINGERING LIGHT
RAIN TO DELAY THE ONSET OF THE WARMUP A BIT IN THE WESTERN
PIEDMONT...WHICH SHOULD STILL REACH THE MID 60S...WITH LOW TO
MID 70S ELSEWHERE...AND POSSIBLY SOME UPPER 70S SOUTHEAST.
THE FRONTAL ZONE WILL BE SOUTH AND EAST OF THE AREA BY LATE TUESDAY.
THE RELATIVE LULL IN PRECIP CHANCES WILL BE SHORT-LIVED...HOWEVER...
AS A SURFACE LOW DEVELOPING IN THE NORTHCENTRAL GULF LIFTS NORTH
INTO THE TENNESSEE VALLEY AND PULLS THE FRONTAL ZONE BACK TO THE
WEST...WHICH WILL MAINTAIN THE MILD AIRMASS OVER THE REGION WITH
MINS MOSTLY IN THE MID AND UPPER 50S.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 255 AM MONDAY...
UNSETTLED WEATHER IS EXPECTED FOR WEDNESDAY INTO THURSDAY... AS A
LOW LEVEL FRONTAL ZONE MOVES INTO THE REGION AND WAVERS ACROSS THE
AREA BEFORE FINALLY MOVING TO THE EAST OF CENTRAL NC BY LATE WEEK
INTO THE WEEKEND.
WEDNESDAY THROUGH THURSDAY: ADDITIONAL SW ENERGY IS EXPECTED TO LIFT
FROM THE PLAINS INTO THE GREAT LAKES ON WEDNESDAY... HELPING TO
SUPPRESS THE SUB-TROPICAL RIDGE FURTHER EAST AND SOUTH. THIS SHOULD
HELP THE LOW LEVEL FRONTAL ZONE TO SLOWLY PUSH INTO CENTRAL NC FROM
THE WEST AND NORTH. MULTIPLE AREAS OF WEAK LOW PRESSURE ARE EXPECTED
TO TRACK ALONG THE SURFACE FRONT AS IT SHIFTS INTO OUR AREA LATE
WEDNESDAY INTO WEDNESDAY NIGHT. THIS SHOULD RESULT IN RAIN/SHOWERING
OVERSPREADING THE AREA ON WEDNESDAY... WITH PERHAPS SOME EMBEDDED
THUNDERSTORMS. IF ENOUGH SURFACE INSTABILITY DEVELOPS ON WEDNESDAY
WE WILL CERTAINLY HAVE GOOD/SUFFICIENT DEEP LAYER SHEAR FOR A STRONG
TO EVEN SEVERE STORM... BUT OVERALL SURFACE INSTABILITY LOOKS TO BE
THE LIMITING FACTOR. THE BIGGER STORY WILL LIKELY BE THE RAINFALL
AMOUNTS... WHICH MAY BE UPWARDS OF AN INCH AGAIN IN THE NORTHWESTERN
PIEDMONT. HOWEVER... WE SHOULD REMAIN RATHER MILD FOR WEDNESDAY...
WITH HIGHS GENERALLY RANGING FROM THE MID 60S NW TO THE LOWER TO MID
70S SE.
CHANCES FOR SHOWERS WILL LINGER WEDNESDAY NIGHT INTO THURSDAY AS THE
FRONT SLOWLY CROSSES THE AREA. EXPECT LOW TEMPS THURSDAY MORNING
WILL RANGE FROM THE MID 50S NW TO THE MID 60S SE. HIGHS THURSDAY ARE
EXPECTED TO RANGE FROM THE UPPER 50S NW TO THE UPPER 60S SE.
THURSDAY NIGHT THROUGH SUNDAY: DRIER AND COLDER AIR IS EXPECTED TO
SPREAD INTO THE AREA LATE WEEK INTO THE WEEKEND... AS CYCLONIC FLOW
ALOFT RETURNS TO THE EASTERN U.S. THIS SHOULD RESULT IN TEMPS NEAR
TO SLIGHTLY BELOW NORMAL... ALONG WITH A RETURN TO DRY WEATHER.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
AS OF 100 AM MONDAY...
AVIATION CONDITIONS WILL DETERIORATE ACROSS CENTRAL NC THROUGH 12Z
AS A SFC COLD FRONT DROPS SOUTHWARD ACROSS THE REGION. CEILINGS WILL
EVENTUALLY LOWER INTO THE IFR CATEGORY WITH POCKETS OF LIFR HIGHLY
PROBABLE. AREAS OF LIGHT RAIN WILL DEVELOP BETWEEN 09Z-13Z AND
PERSIST THROUGH MUCH OF THE AFTERNOON. LIGHT SOUTHERLY WINDS AHEAD
OF THE FRONT WILL VEER TO A NELY DIRECTION WITH THE FROPA...AND
INCREASE TO AROUND 13KTS WITH GUSTS AROUND 20KTS.
THE PATCHES OF LIGHT RAIN WILL SLOWLY DIMINISH LATE TONIGHT INTO
EARLY TUESDAY THOUGH MVFR/IFR CEILINGS WILL PERSISTS THROUGH TUESDAY
MORNING. THE COLD FRONT IS EXPECTED TO LIFT NWD AS A WARM FRONT
TUESDAY. IN THE WARM SECTOR BEHIND THE FRONT...AVIATION CONDITIONS
MAY TEMPORARILY BECOME VFR TUESDAY AFTERNOON THROUGH TUESDAY
EVENING. ANOTHER ROUND OF ADVERSE AVIATION CONDITIONS EXPECTED
WEDNESDAY INTO THURSDAY AS ANOTHER FRONTAL SYSTEM AFFECTS OUR
REGION. IMPROVING AVIATION CONDITIONS ANTICIPATED BY FRIDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BLAES
NEAR TERM...22/VINCENT/BLAES
SHORT TERM...MLM
LONG TERM...BSD
AVIATION...WSS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
100 AM MON DEC 28 2015
.SYNOPSIS... A STRONG SUB-TROPICAL RIDGE OF HIGH PRESSURE WILL
PERSIST OFF THE SOUTHEAST COAST FOR THE NEXT FEW DAYS. A COLD FRONT
WILL DROP SOUTH THROUGH VIRGINIA TONIGHT AND INTO NORTH CAROLINA ON
MONDAY. A STRONG STORM SYSTEM WILL DEVELOP IN THE LOWER MISSISSIPPI
VALLEY ON MONDAY AND MOVE INTO THE EASTERN GREAT LAKES ON TUESDAY.
&&
.NEAR TERM /THROUGH MONDAY NIGHT/...
AS OF 1000 PM SUNDAY...
NO ADDITIONAL MAJOR CHANGES TO THE FORECAST TONIGHT. THE COLD FRONT
THAT WILL MOVE IN LATER TONIGHT IS CURRENTLY PUSHING THROUGH THE MID-
ATLANTIC STATES...WITH NORTHERLY WINDS APPROACHING CENTRAL VA. HIGH
CLOUDS ARE PLENTIFUL ACROSS THE CAROLINAS...WHICH MAY MAKE IT HARD
FOR FOG TO DEVELOP HERE IN CENTRAL NC...ESPECIALLY IN THE WESTERN
PIEDMONT. HOWEVER... THE HRRR STILL SHOWS A BRIEF PERIOD OF FOG OR
VERY LOW STRATUS IMMEDIATELY AHEAD OF THE FRONT AS WINDS
DIMINISH...MORE TOWARD 09-12Z. -22
PREVIOUS FORECAST... THE ANOMALOUS WARM SECTOR IN PLACE THIS PAST
WEEK WILL PERSIST OVER THE MAJORITY OF CENTRAL NC NIGHT...EXCEPT FOR
THE NORTHERN PIEDMONT AND NE COASTAL PLAIN LATER TONIGHT WHEN A BACK-
DOOR COLD FRONT PROGRESSES SOUTHWARD FROM VA INTO NC ~08-12Z. IN THE
NORTH...LOWS WILL PRIMARILY BE A FUNCTION OF COLD ADVECTION IN THE
WAKE OF THE COLD FRONTAL PASSAGE LATE TONIGHT (08-12Z MON)...PERHAPS
AIDED BY EVAPORATIVE COOLING ATTENDANT LIGHT RAIN AS SOUTH/SE LOW-
LEVEL FLOW (925-850 MB )ADVECTS A WARM/MOIST AIRMASS NORTHWARD ATOP
THE SHALLOW COLDER AIRMASS ADVECTING SOUTHWARD. IN THE SOUTH...LOW
TEMPS WILL BE DRIVEN BY RADIATIONAL COOLING (MAGNITUDE OF WHICH WILL
DEPEND ON CLOUD COVER). -VINCENT
AS THE FRONT DROPS SOUTH ON MONDAY...AREAS OF RAIN WILL LIKELY
EXPAND IN THE DEVELOPING OVER RUNNING PATTERN WHICH WILL LOCK IN
CLOUDS AND CONTRIBUTE ADDITIONAL COOLING. TEMPERATURES ACROSS THE
NORTHERN PIEDMONT AND NORTHERN COASTAL PLAIN WILL FALL INTO THE
UPPER 40S BY LATE IN THE DAY WITH THE COLD FRONT PUSHING THROUGH ALL
OF CENTRAL NC BY NIGHTFALL. THE COOLER AIR MASS WILL BE SLOWER TO
ARRIVE ACROSS THE SOUTHERN PIEDMONT AND SANDHILLS BY THE CLOUDS AND
PRECIPITATION WILL LIMIT THE DIURNAL TEMPERATURE RECOVERY.
NWP GUIDANCE GUIDANCE HAS BEEN CONSISTENT IN QUICKLY SCOURING THE
LOW LEVEL COLD AIR MASS ON MONDAY NIGHT WITH THE WARM FRONT PUSHING
NORTH INTO THE DC AREA BY DAYBREAK TUESDAY. PAST EXPERIENCE SUGGESTS
THAT THIS IS LIKELY TOO FAST AND HAVE SLOWED THE PASSAGE OF THE WARM
FRONT BY 2-4 HOURS WHICH STILL MAY NOT BE SUFFICIENT IF THE HYBRID
CAD EVENT LOCKS IN. STILL IT WILL BE A CLOUDY AND DAMP NIGHT WITH
PERIODS OF RAIN AND TEMPERATURES STEADY AND THEN BEGINNING TO RISE
TOWARD DAYBREAK. -BLAES
&&
.SHORT TERM /TUESDAY AND TUESDAY NIGHT/...
AS OF 230 PM SUNDAY...
MODELS HAVE CONSISTENTLY FORECAST THE CAD TO SCOUR RAPIDLY LATE
MONDAY NIGHT AHEAD OF AN APPROACHING WEAK COLD FRONT. ANY LINGERING
LIGHT RAIN MONDAY NIGHT WILL TAPER TO SCATTERED SHOWERS EARLY
TUESDAY AS LOW LEVEL FLOW VEERS AROUND TO SOUTH AND SOUTHWEST...
ENDING THE ISENTROPIC LIFT AND INITIATING STRONG WARM AIR ADVECTION.
WOULD EXPECT DENSER CLOUD COVERAGE AND POSSIBLY SOME LINGERING LIGHT
RAIN TO DELAY THE ONSET OF THE WARMUP A BIT IN THE WESTERN
PIEDMONT...WHICH SHOULD STILL REACH THE MID 60S...WITH LOW TO
MID 70S ELSEWHERE...AND POSSIBLY SOME UPPER 70S SOUTHEAST.
THE FRONTAL ZONE WILL BE SOUTH AND EAST OF THE AREA BY LATE TUESDAY.
THE RELATIVE LULL IN PRECIP CHANCES WILL BE SHORT-LIVED...HOWEVER...
AS A SURFACE LOW DEVELOPING IN THE NORTHCENTRAL GULF LIFTS NORTH
INTO THE TENNESSEE VALLEY AND PULLS THE FRONTAL ZONE BACK TO THE
WEST...WHICH WILL MAINTAIN THE MILD AIRMASS OVER THE REGION WITH
MINS MOSTLY IN THE MID AND UPPER 50S.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 230 PM SUNDAY...
A POTENT SHORT WAVE MOVING ACROSS THE GREAT LAKES REGION WILL PUSH
THE SUBTROPICAL RIDGE OVER THE EASTERN CONUS FURTHER OFFSHORE.
THE ENSUING DEEP SOUTHWEST FLOW WILL BE NEAR-PARALLEL TO THE SURFACE
FRONTAL ZONE OVER THE AREA...SO IT WILL LINGER ACROSS THE AREA WITH
PERIODS OF FAIRLY WIDESPREAD SHOWER COVERAGE FROM WEDNESDAY THROUGH
THURSDAY. WILL HAVE LIKELY POPS ACROSS THE ENTIRE AREA WED AND WED
NIGHT...SHIFTING TO THE EAST ON THURSDAY WHEN THE FRONT IS FINALLY
PUSHED OFFSHORE BY A STRONGER UPPER TROF ROTATING ACROSS THE
MIDWEST. HIGHS BOTH WED AND THU WILL BE IN THE 60S AFTER MORNING
LOWS IN THE 50S.
HIGH PRESSURE WILL BE BUILDING IN AS THE FRONT MOVES OFFSHORE
THURSDAY NIGHT AND A COOLER AIRMASS WILL SETTLE INTO THE AREA. THE
TRANSITION TO EAST COAST TROFFING WILL BE A RELATIVELY SLOW
PROCESS...WITH ENSUING SHORT WAVES PROGRESSIVELY DEEPENING THE TROF
AS THEY DIG INTO THE UPPER MIDWEST/OHIO VALLEY ON FRIDAY AND
SATURDAY. INITIAL SEASONABLY MILD HIGH TEMPERATURES IN THE 50S
FRIDAY WILL FALL INTO THE MID TO UPPER 40S FOR THE WEEKEND AS THE
PROGRESSIVE SHORT WAVES DEEPEN THE UPPER TROF AND PROVIDE US WITH
REINFORCING WAVES OF COOLER DRY AIR. RADIATIONAL CONDITIONS WILL BE
MORE FAVORABLE IN THE DRY AIRMASS AND WEAKER FLOW AS THE SURFACE
HIGH BUILDS IN...RESULTING IN MINS FALLING INTO THE 30S SATURDAY
MORNING...WITH MOST AREAS AT OR BELOW FREEZING SUNDAY MORNING.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
AS OF 100 AM MONDAY...
AVIATION CONDITIONS WILL DETERIORATE ACROSS CENTRAL NC THROUGH 12Z
AS A SFC COLD FRONT DROPS SOUTHWARD ACROSS THE REGION. CEILINGS WILL
EVENTUALLY LOWER INTO THE IFR CATEGORY WITH POCKETS OF LIFR HIGHLY
PROBABLE. AREAS OF LIGHT RAIN WILL DEVELOP BETWEEN 09Z-13Z AND
PERSIST THROUGH MUCH OF THE AFTERNOON. LIGHT SOUTHERLY WINDS AHEAD
OF THE FRONT WILL VEER TO A NELY DIRECTION WITH THE FROPA...AND
INCREASE TO AROUND 13KTS WITH GUSTS AROUND 20KTS.
THE PATCHES OF LIGHT RAIN WILL SLOWLY DIMINISH LATE TONIGHT INTO
EARLY TUESDAY THOUGH MVFR/IFR CEILINGS WILL PERSISTS THROUGH TUESDAY
MORNING. THE COLD FRONT IS EXPECTED TO LIFT NWD AS A WARM FRONT
TUESDAY. IN THE WARM SECTOR BEHIND THE FRONT...AVIATION CONDITIONS
MAY TEMPORARILY BECOME VFR TUESDAY AFTERNOON THROUGH TUESDAY
EVENING. ANOTHER ROUND OF ADVERSE AVIATION CONDITIONS EXPECTED
WEDNESDAY INTO THURSDAY AS ANOTHER FRONTAL SYSTEM AFFECTS OUR
REGION. IMPROVING AVIATION CONDITIONS ANTICIPATED BY FRIDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BLAES
NEAR TERM...22/VINCENT/BLAES
SHORT TERM...MLM
LONG TERM...MLM
AVIATION...WSS
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
458 AM EST MON DEC 28 2015
.SYNOPSIS...
A WARM FRONT WILL BE LIFTING NORTH LATE TODAY AS LOW PRESSURE TRACKS
NORTH-NORTHEAST FROM ARKANSAS TO CENTRAL ILLINOIS. THIS LOW WILL
TRACK ACROSS SOUTHERN MICHIGAN AND INTO ONTARIO CANADA
TONIGHT...TAKING BOTH THE WARM AND COLD FRONTS ACROSS NORTHERN OHIO
AND NW PA. HIGH PRESSURE WILL BRIEFLY RESIDE ACROSS THE OHIO VALLEY
TUESDAY NIGHT. A FEW WEAK DISTURBANCES WILL BE MOVING ACROSS THE
GREAT LAKES FOR THE SECOND HALF OF THE WEEK WITH AN EXPANSIVE AREA
OF HIGH PRESSURE ACROSS THE MIDWEST AND THE LOWER OHIO VALLEY.
&&
.NEAR TERM /THROUGH TONIGHT/...
COMPLEX SYSTEM HEADED OUR WAY. THE DAY STARTS WITH HIGH PRESSURE SITTING
TO OUR NNW AND A COOL NNE FLOW ACROSS NRN OH/NW PA TO START.
PRECIPITATION CONCERNS HIGHEST AT OUR NW AND NE CORNERS...TOLEDO
AND NW PA.
FIRST ACROSS TOLEDO/NW OH FOR THE FIRST PART OF TODAY...HAVE PUT
UP A WINTER WEATHER ADVISORY FOR TODAY INTO EARLY EVENING. SURFACE
TEMPERATURES WILL BE HOVERING BETWEEN 30 AND 33 DEGREES
TODAY...NOT RISING UNTIL TONIGHT WHEN THE WARM FRONT LIFTS NORTH
AND STRONG SOUTHERLY WINDS BRING WARMER AIR NORTHWARD. EXPECT A
DROP IN TEMPS AS PRECIP STARTS...THEN HOLDING STEADY. BORDERLINE
CONDITIONS BETWEEN SLEET AND FREEZING RAIN. FURTHER TO OUR NORTH
COLD AIR IS DEEPER WITH SLEET MORE LIKELY. TOLEDO IS BORDERLINE.
OHDOT PAVEMENT TEMPS ARE READING AROUND 35 DEGREES...SO IMPACTS
SHOULD BE LESS. BIG QUESTION WILL BE WHEN DO TEMPS REALLY PUSH
ABOVE FREEZING. COULD THE STRONG EASTERLY FLOW OFF OF A LAKE IN
THE 40S BE ENOUGH TO WARM SURFACE TEMPS EARLY OR WILL WE HAVE TO
WAIT FOR THE SOUTHERLY FLOW? ONCE TEMPS GO UP THEY WILL CONTINUE
TO WARM INTO THE LOWER 40S FOR TONIGHT.
ACROSS NW PA...HAVE STARTED THE FREEZING RAIN ADVISORY
SOONER...STARTING IT AT NOON. LATEST HRRR WHICH HAS A GOOD HANDLE
ON CURRENT PICTURE HAS PRECIP MOVING IN FASTER THAN PREVIOUS
FORECAST. ANY PRECIP BEFORE NOON WOULD BE LIGHT. SIMILAR CONCERNS
WITH TEMPERATURES AND WHEN EXACTLY THEY WILL WARM ABOVE FREEZING.
HAVE MADE THAT TRANSITION EARLIER IN THE EVENING...ONLY HANGING ON
TO THE WINTRY PRECIPITATION ACROSS THE FAR EAST. IT IS POSSIBLE
THAT THE FZ RAIN ADV MAY BE ABLE TO END EARLY.
OTHERS MAY SEE SOME SPOTTY/PATCHES OF FREEZING RAIN FIRST THING
THIS MORNING WITH LITTLE OR NO IMPACT. TEMPS MAY BE HARD PRESSED
TO GET MUCH BELOW 32.
RAINFALL AMOUNTS ARE EXPECTED TO RANGE FROM A HALF INCH TO ONE
INCH. LOCALLY HEAVIER AMOUNTS ARE POSSIBLE ESPECIALLY IF WE GET
THUNDER UP INTO THE AREA. HAVE NOT INCLUDED THE THUNDER YET IN
THE FORECAST. HAVE HIGHLIGHTED THE RAINFALL AND POSSIBLE MINOR
FLOODING IN THE HAZARDOUS WEATHER OUTLOOK. AREA CREEKS AND STREAMS
WILL CONTINUE TO RUN HIGH...WITH SOME OF OUR RIVER FORECAST POINTS
REACHING INTO MINOR FLOOD. IF RAINFALL FORECAST NEEDS TO BE
INCREASED THEN A FLOOD WATCH WILL BE NEEDED. RAIN WILL LESSEN
DURING THE OVERNIGHT HOURS...BUT LINGER WITH MOIST CYCLONIC FLOW.
WILL HAVE A OUTRIGHT STIFF EASTERLY WIND PICK UP FOR THIS
AFTERNOON...COMING AROUND TO THE SE AND SOUTH BY TONIGHT. FOR NOW
HAVE A WIND ADVISORY FOR ERIE COUNTY PA WITH THE ENHANCED
DOWNSLOPE. OTHERS...FOR NOW...WILL HAVE GUSTS OF 35 TO 45 MPH.
TEMPS WILL RISE TONIGHT INTO THE LOWER AND MID 40S. WE MAY EVEN
SEE A 50 OR TWO.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
THE PERSISTENT SOUTHEAST RIDGE WILL BEGIN TO BREAK DOWN THROUGH
THE COURSE OF THE WEEK. NOT A LOT OF COLD AIR BEHIND MONDAY`S
SYSTEM....BUT LOW LEVEL MOISTURE WILL LINGER AND THEREFORE THE
CLOUDS TOO. ANY REMAINING LIGHT RAIN WILL TAPER OFF DURING THE DAY
TUESDAY. A WEAK DISTURBANCE WEDNESDAY WILL GIVE US ANOTHER CHANCE
FOR LIGHT RAIN...WITH SNOW SHOWERS POSSIBLE LATE WEDNESDAY NIGHT
AS THE COLDER AIR FILTERS INTO THE REGION. MID 40S TUESDAY AND
LOWER 40S FOR HIGHS WEDNESDAY. WIDESPREAD TEMPS BELOW FREEZING
WEDNESDAY NIGHT.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
NOT MANY CHANGES AGAIN TODAY AS A MORE WINTRY PATTERN GETS
ESTABLISHED. IT LOOKS LIKE WE WILL SEE SEVERAL DAYS WITH LAKE
EFFECT SNOW POTENTIAL. THE 00Z ECMWF IS A LITTLE QUICKER BRINGING
IN THE COLDER AIR ALOFT ON THURSDAY. THE LAKE EFFECT WILL GET GOING
LATE IN THE DAY AND WILL STICK WITH LIKELY POPS THURSDAY NIGHT.
GIVEN A 260 TO 270 DEGREE FLOW THE SNOW WILL NOT SPREAD VERY FAR
INLAND ACROSS NE OHIO. SOME ACTIVITY IS EXPECTED ON FRIDAY AS WELL.
SATURDAY WILL SEE SOME WEAK WARM AIR ADVECTION WHICH MAY CAUSE THE
PRECIP ACTIVITY TO DIMINISH SOME. A REINFORCING SHOT OF COLD AIR
WILL ARRIVE SATURDAY NIGHT INTO SUNDAY BEHIND ANOTHER TROUGH. WILL
SEE PRECIP CHANCES RAMP UP AGAIN AT THAT TIME. AREAS AWAY FROM THE
SNOWBELT WILL SEE LITTLE MORE THAN A FEW FLURRIES DURING THE PERIOD.
THERE SHOULD BE A FAIR AMOUNT OF CLOUDINESS. TEMPS WILL BE NEAR
NORMAL WITH HIGHS MAINLY IN THE LOW TO MID 30S.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
METEOROLOGICAL MESS SHAPING UP OVER THE NEXT 24 TO 36 HOURS.
PRECIPITATION WILL LIFT BACK NORTH WITH THE WARM FRONT DURING THE
DAY TOMORROW. SOME LOW LEVEL COLD AIR ADVECTION WILL TAKE PLACE
OVERNIGHT INTO TOMORROW AND THIS WILL SLIDE UNDER WARM AIR
ADVECTION ALOFT AHEAD OF THE WARM FRONT. THE MESS COMES IN BECAUSE
IT ALL DEPENDS ON TIMING OF THE PRECIPITATION COMPARED TO THE
TIMING OF THE RETREAT OF THE COLDER AIR AT THE SURFACE. EXPECTING
PRECIPITATION TO BEGIN IN THE FORM OF POSSIBLE SNOW AT TOLEDO AND
THEN A MIX OF FREEZING RAIN/SLEET DURING THE AFTERNOON HOURS.
ELSEWHERE...A MIX OF RAIN/SNOW TO ALL RAIN WILL OCCUR DUE TO LATER
TIMING OF THE PRECIPITATION. HELD ERIE AT ALL RAIN AS DOWN SLOPING
FROM THE HIGHER TERRAIN TO THE EAST WILL WARM SURFACE TEMPERATURES
ABOVE FREEZING. IFR/LIFR DEVELOPING THROUGH THE FORECAST PERIOD AS
WELL IN VISIBILITIES AND CEILINGS.
OUTLOOK...WIDESPREAD NON VFR INTO TUESDAY. NON VFR CONDITIONS
LIKELY AGAIN WEDNESDAY EVENING INTO THURSDAY.
&&
.MARINE...
WILL GO AHEAD AND UPGRADE THE GALE WATCH TO A WARNING FOR
THE WEST HALF OF THE LAKE. DO NOT THINK WE WILL GET SUSTAINED GALES
SO THIS WILL BE A MARGINAL EVENT AND WILL HAVE TO RELY ON THE
FREQUENT GUST CRITERIA. IT APPEARS WATER LEVELS IN THE WEST BASIN
WILL STAY ABOUT A FOOT BELOW LAKESHORE FLOOD WARNING LEVELS.
FORTUNATELY THE NE TO E FETCH WON`T BE PROLONGED WITH SE FLOW
DEVELOPING THIS EVENING. HAVE GONE AHEAD AND EXTENDED THE SMALL
CRAFT IN THE EAST THROUGH TOMORROW. EXPECT THE FLOW TO EVENTUALLY
BECOME SW ON TUESDAY BEHIND THE COLD FRONT. SW TO W FLOW WILL THEN
CONTINUE THROUGH THE END OF THE WEEK. WILL LIKELY NEED SMALL CRAFT
HEADLINES MUCH OF THE WEEK.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...WINTER WEATHER ADVISORY FROM 9 AM THIS MORNING TO 7 PM EST
THIS EVENING FOR OHZ003-006.
PA...WIND ADVISORY FROM 10 PM THIS EVENING TO 7 AM EST TUESDAY FOR
PAZ001-002.
FREEZING RAIN ADVISORY FROM NOON TODAY TO MIDNIGHT EST TONIGHT
FOR PAZ002-003.
MARINE...GALE WARNING FROM 1 PM THIS AFTERNOON TO 10 PM EST THIS
EVENING FOR LEZ142>146-162>166.
SMALL CRAFT ADVISORY UNTIL 10 PM EST TUESDAY FOR LEZ147>149.
&&
$$
SYNOPSIS...OUDEMAN
NEAR TERM...OUDEMAN
SHORT TERM...OUDEMAN
LONG TERM...KUBINA
AVIATION...LOMBARDY
MARINE...KUBINA
AREA FORECAST DISCUSSION
NWS NORMAN OK
1049 PM CST SUN DEC 27 2015
.DISCUSSION...
&&
.AVIATION...
IFR CONDITIONS ARE EXPECTED THROUGH THE FIRST HALF OF MONDAY.
BLIZZARD CONDITIONS WILL OCCUR IN WESTERN OKLAHOMA WITH FREEZING
RAIN...SLEET...THEN SNOW OVER MUCH OF THE WESTERN HALF OF THE
STATE. VERY STRONG NORTH WINDS WILL GUST OVER 40 MPH THROUGH
MONDAY MORNING BEFORE SUBSIDING IN THE AFTERNOON. SNOW WILL END BY
MIDDAY VFR CONDTIONS WILL RETURN THROUGH THE AFTERNOON AND WINDS
WILL BECOME LIGHT AFTER SUNSET.
&&
.PREV DISCUSSION... /ISSUED 752 PM CST SUN DEC 27 2015/
UPDATE...
NO CHANGES TO CURRENT HEADLINES/FORECAST AT THIS TIME. CONCERNS
THIS EVENING INCLUDE PROSPECTS FOR INCREASING POWER OUTAGES AND
DANGEROUS TRAVEL CONDITIONS ACROSS THE REGION THROUGH MONDAY
MORNING.
THE ONGOING WINTER STORM APPEARS TO BE EVOLVING MUCH AS EXPECTED.
WATER VAPOR/RADAR SHOWS AN EXTENSIVE PRECIP SHIELD NOW EXITING
OKLAHOMA TO THE EAST. FREEZING DRIZZLE WITH INTERMITTENT LIGHT
SNOW IS FALLING IN THE RELATIVELY LIGHT RADAR ECHOES SEEN OVER
MUCH OF WESTERN/CENTRAL OKLAHOMA. FOCUS NOW SHIFTS TO THE NEXT
BOUT OF DEEP FORCING/ASCENT EVIDENT IN VAPOR/RADAR IMAGERY
EMERGING FROM WESTERN NORTH TEXAS.
THIS RENEWED ROUND OF PRECIPITATION IS WELL HANDLED BY SEVERAL OF
THE HIGH RESOLUTION MODELS. THE HRRR AND TTU WRF SOLUTIONS DEPICT
MODERATE TO HEAVY PRECIP OVERSPREADING WESTERN OKLAHOMA IN THE
NEXT 1 TO 3 HOURS...THEN CENTRAL OKLAHOMA BY 05-07Z. PRECIP TYPES
RANGE FROM ALL SNOW IN NORTHWEST OKLAHOMA...TO A WINTRY MIX
ELSEWHERE...WITH INDICATIONS THAT SLEET MAY BE MORE DOMINANT IN
SOUTHWEST AND CENTRAL OKLAHOMA WHERE 1 TO 2 INCH SLEET
ACCUMULATIONS MAY OCCUR. PROFILES SUPPORT A TRANSITION TO
LIGHT/WIND BLOWN SNOW BY MID MORNING MONDAY. WIND SPEEDS APPEAR
TO REMAIN IN THE 20 TO 30 MPH RANGE THROUGH AT LEAST 18Z
MONDAY...WHICH WILL EXACERBATE ONGOING ISSUES WITH DAMAGED
UTILITIES/POWER OUTAGES. WINTRY PRECIPITATION SHOULD BEGIN TO
WANE DURING THE MIDDAY/EARLY AFTERNOON HOURS MONDAY...WITH SOME
WRAP AROUND SNOW LINGERING OVER NORTH/CENTRAL OKLAHOMA BEFORE
ENDING.
PREV DISCUSSION... /ISSUED 622 PM CST SUN DEC 27 2015/
DISCUSSION...
AVIATION...
IFR CONDITIONS ARE EXPECTED THROUGH THE FIRST HALF OF MONDAY.
BLIZZARD CONDITIONS WILL OCCUR IN WESTERN OKLAHOMA WITH FREEZING
RAIN...SLEET...THEN SNOW OVER MUCH OF THE WESTERN HALF OF THE
STATE. VERY STRONG NORTH WINDS WILL GUST OVER 40 MPH THROUGH
MONDAY MORNING BEFORE SUBSIDING IN THE AFTERNOON.
PREV DISCUSSION... /ISSUED 345 PM CST SUN DEC 27 2015/
DISCUSSION...
PRECIPITATION CONTINUES TO SLOWLY MOVE NORTHWARD OVER PORTIONS OF
WEST TEXAS AND THE SOUTHERN TX PANHANDLE THIS AFTERNOON...AS THE
MID TO UPPER LOW SWINGS ENE. THE LOW WILL BEGIN TO LIFT TO THE
NORTH LATE TONIGHT OVER NORTH TEXAS. TWO LOCATIONS OF
PRECIPITATION WILL ACCOMPANY IT. THE FIRST WILL BE MOSTLY SNOW
MOVING INTO WESTERN NORTH TEXAS...SOUTHWESTERN OK...AND WESTERN OK
THIS EVENING...AND EVENTUALLY INTO NORTHERN AND NORTHWESTERN OK
EARLY TOMORROW MORNING. THE OTHER WILL BE LOCATED OVER CENTRAL OK
WHERE SLEET...SNOW...AND SOME FREEZING RAIN WILL OCCUR. THE ICE
STORM WARNING HAS BEEN CANCELLED AND REPLACED WITH A WINTER STORM
AND BLIZZARD WARNINGS. THE DEPTH OF THE COLD AIR IS TOO DEEP FOR
FZRA. THE HEAVIEST SNOW WILL IMPACT W/SW OK LATE TONIGHT RESULTING
IN NEAR 0 VISBY. IT`S A BIT UNCLEAR HOW FAR NORTH THE HEAVIEST
SNOW WILL MAKE IT, BUT DECIDED TO KEEP BLIZZARD WARNING IN EFFECT
FOR NW OK FOR NOW. THIS MAY BE DOWNGRADED AT A LATER TIME.
SOME ICE ACCUMULATION IS STILL EXPECTED THROUGH EARLY
TOMORROW MORNING, ESPECIALLY ACROSS CENTRAL/SOUTH CENTRAL OK WHERE
WARMER NOSE AT 700 MB WILL NUDGE IN AROUND THE LOW. HOWEVER, IT
SHOULD BE BRIEF AND TOTALS SHOULD REMAIN BELOW WARNING CRITERIA.
REGARDLESS, WIND SPEEDS WILL ONLY SLOWLY DECREASE THROUGH EARLY
TOMORROW AND POWER OUTAGES ARE STILL A CONCERN. SLEET ACCUMULATION
LATE TONIGHT THROUGH TOMORROW WILL LIKELY BE HIGHEST ACROSS
CENTRAL OK WHERE SUFFICIENT MOISTURE AND LIFT THROUGH THE
DENDRITIC ZONE WILL RESIDE...BEFORE A TRANSITION TO SNOW OCCURS
JUST BEFORE SUNRISE. THE LOW WILL QUICKLY EXIT OUR REGION TO THE
NE BY 18Z TOMORROW, BUT TRAIL SOME PATCHY SNOW/BLOWING SNOW
ACROSS CENTRAL AND NORTHERN OK PERHAPS THROUGH LUNCHTIME.
AT LEAST A 24 HOUR BREAK IN THE PRECIPITATION IS EXPECTED TUE
BEFORE A SHORTWAVE TROUGH MOVES OUT OF THE SOUTHERN ROCKIES TUES
NIGHT. THE TREND WITH THIS WAVE HAS BEEN TO DIG A BIT SOUTH AND
SLIGHTLY DEEPER. BASED ON THIS, AND MOISTURE PROFILES ACROSS
NORTHERN OK, DECIDED TO BUMP POPS INTO THE HIGH CHC CAT TUE NIGHT.
HOWEVER, IT WILL BE PROGRESSIVE SO SNOW AMOUNTS SHOULD REMAIN
AROUND 1 IN. AFTER WED AM, PRECIP CHANCES WILL END FOR THE WEEK
BUT BELOW AVG TEMPS WILL PERSIST.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 28 32 18 36 / 90 80 0 0
HOBART OK 24 31 15 33 / 90 20 0 0
WICHITA FALLS TX 28 36 19 41 / 100 20 0 10
GAGE OK 21 27 7 28 / 80 30 0 20
PONCA CITY OK 27 31 14 32 / 100 80 10 0
DURANT OK 36 39 27 46 / 90 50 0 0
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...WINTER STORM WARNING UNTIL 6 PM CST MONDAY FOR OKZ006>008-
011>013-015>019-022>025-027>029-034>038.
BLIZZARD WARNING UNTIL 6 PM CST MONDAY FOR OKZ004-005-009-010-
014-021-033.
WINTER WEATHER ADVISORY UNTIL 6 PM CST MONDAY FOR OKZ020-026-030-
039-040-044-045.
FLASH FLOOD WATCH UNTIL 6 AM CST MONDAY FOR OKZ026-028>032-
039>043-045>048-050>052.
TX...WINTER STORM WARNING UNTIL 6 PM CST MONDAY FOR TXZ084-085-087.
BLIZZARD WARNING UNTIL 6 PM CST MONDAY FOR TXZ083.
WINTER WEATHER ADVISORY UNTIL 6 PM CST MONDAY FOR TXZ086-088>090.
&&
$$
99/09/09
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
340 AM CST MON DEC 28 2015
.SHORT TERM...(TODAY THROUGH TUESDAY AFTERNOON)
ISSUED AT 339 AM CST MON DEC 28 2015
MODELS SEEMS TO HAVE CONVERGED TOWARDS AN AGREEABLE SOLN THIS
MORNING...PIVOTING THE UPPER LOW THROUGH EASTERN MISSOURI AND INTO
NORTHERN MICHIGAN BY TUESDAY MORNING. THIS MARKS A SLIGHTLY MORE
EASTWARD TRAJECTORY THAN PREVIOUSLY ADVERTISED...LIKELY DUE TO SOME
IMPACT FROM CONVECTION ASSOCIATED WITH THE WAVE. THE OVERALL
CONSENSUS PLACES THE TRACK OF THIS WAVE SLIGHTLY FURTHER WEST THAN
THE GFS/NAM...AND MORE ALONG THE LINE OF THE ECMWF/GEM.
PRECIPITATION ALREADY ONGOING OVER THE LOWER MO RIVER VALLEY WILL
CONTINUE TO PRESS NORTHWARD TOWARDS THE CWA BY MID-MORNING.
STRONG DIVERGENCE ALOFT COMBINED WITH BROAD BUT INTENSE LOW LEVEL
WARM ADVECTION SHOULD SEND A BROAD AREA OF LIGHT TO MODERATE SNOWS
NORTHWARD THROUGH THE DAY. HRRR SUGGESTS INITIAL BANDS REACH SIOUX
CITY AND STORM LAKE BY 8AM...THE I-90 CORRIDOR BY NOON...AND THE
NORTHERN CWA AFTER MID-AFTERNOON.
MODELS ALSO GRASPING SLIGHTLY BETTER AT WEAKER PV ANOMALY OVER
NORTHERN KANSAS AND SOUTH CENTRAL NEBRASKA. THIS WAVE WILL PIVOT
NORTHEAST WITH THE STRONGER EASTERN LOW BY MONDAY NIGHT...AND
CONTINUES TO SHOW SIGNS OF INTENSIFICATION GIVEN NICE JET STREAK
ALOFT. I DO HAVE SOME CONCERNS ABOUT THE IMPACT OF A DRY INTRUSION
OF AIR WITH THE 700:600 MB LAYER ADVERTISED BY THE NAM ARRIVING FROM
THE SOUTHWEST THIS AFTERNOON. THIS HAS POTENTIAL TO REALLY LIMIT
SNOWFALL RATES DURING THE SECOND HALF OF THE AFTERNOON.
MOVING AHEAD...THIS SECONDARY PV ANOMALY MAY LINGER JUST NORTH OF
THE TRI-STATE AREA WELL INTO TUESDAY AND GIVEN UPR DYNAMICS...SHOULD
SUPPORT A LONGER DURATION SNOWFALL OVER THE NORTHERN AND
NORTHEASTERN CWA INTO TUESDAY AFTERNOON.
WHILE QPF AMOUNTS HAVE TRENDED DOWNWARD...SLR VALUES HAVE
TRENDED UPWARDS SLIGHTLY. INITIAL ONSET OF PRECIPITATION MAY SEE 12-
13:1 RATIOS WITH VALUES INCREASING TOWARDS THE 14-15:1 RATIO THROUGH
THE NIGHT. THESE VALUES PUSH THE HIGHEST SNOWFALL TOTALS OVER THE
FAR EASTERN CWA...WITH THE HIGHEST CONCENTRATION OF 6 INCH OR HIGHER
REPORTS OVER MINNESOTA/IOWA COUNTIES. ELSEWHERE...A LONGER DURATION
2 TO 6 INCH SNOWFALL SEEMS LIKELY.
AS FAR AS HEADLINES ARE CONCERNED...WILL PUSH WARNING SLIGHTLY
FURTHER NORTH INTO THE MARSHALL AREA GIVEN POTENTIAL OF 6 - 8 INCHES
OVER 24 HOURS AND IMPACTS FROM WINDS. WILL ALSO ISSUE AN ADVISORY
FOR THE REMAINING AREAS ALONG AND WEST OF I-29. WHILE SNOWFALL
TOTALS ARE SLIGHTLY LOWER...THROUGH COLLABORATION...WILL LEAVE
WARNING IN PLACE FOR NERN NEBRASKA AND FAR SOUTHEASTERN SD COUNTIES.
.LONG TERM...(TUESDAY EVENING THROUGH SUNDAY)
ISSUED AT 339 AM CST MON DEC 28 2015
SNOW WILL BE LIGHT AND BECOMING SPOTTY BY TUESDAY EVENING AND BE
CONCENTRATED IN THE NORTHERN PART OF OUR FORECAST AREA. IN FACT...IT
MAY QUICKLY WEAKEN TO SCATTERED FLURRIES. WILL STILL CARRY THE
LOW...MOSTLY SLIGHT CHANCE POPS...WE HAVE BEEN GOING WITH IN THE
FLAT UPPER FLOW BEHIND THE MAIN SYSTEM. ANY LINGERING FLAKES SHOULD
END WEDNESDAY. AMOUNTS IF ANY WILL BE A HALF INCH OR LESS. LOW
LEVEL.SURFACE FLOW AND WINDS WILL BE NORTHWESTERLY AND SHOULD BE
FAIRLY LIGHT. EXPECT PLENTY OF CLOUDS TO REMAIN THROUGH WEDNESDAY.
TEMPERATURES FOR THE TIME WILL SHOW A SMALL DIURNAL RANGE WITH ABOVE
NORMAL LOWS AND BELOW NORMAL HIGHS.
A DRYING PROCESS IS EXPECTED TO ACCOMPANY A GRADUALLY DEVELOPING
NORTHWESTERLY FLOW ALOFT AND AT THE SURFACE STARTING WEDNESDAY NIGHT
AND THURSDAY. THIS DRY TREND SHOULD CONTINUE THROUGH THE WEEKEND.
TEMPERATURES WILL WARM SOME ON HIGHS WITH THE WARMING TREND OF
COURSE MODIFIED BY SNOW COVER. LOWS SHOULD STAY THE SAME
OR COOL A BIT. WILL GO WITH THE EXTENDED GUIDANCE TEMPERATURES FOR
NOW BUT THINK THEY COULD BE UNDER DOING THE DIURNAL RANGES...
MAINLY ON FORECAST LOWS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1133 PM CST SUN DEC 27 2015
QUIET VFR WEATHER DURING THE OVERNIGHT. NEXT STRONG UPPER LEVEL
SYSTEM BEINGS TO AFFECT THE AREA AFTER DAWN WITH AN INCREASE IN
MID AND HIGH LEVEL CLOUDS. MODELS ARE DIFFERING ON STORM`S TRACK
WITH THE LATEST GFS RUN TAKING IT FURTHER EAST. AT THIS POINT...I
THINK GREAT IMPACTS WILL BE TO THE EAST OF OUR TAF LOCATIONS.
STILL WILL SEE PERIODIC HEAVY SNOW AFTER 18Z-20Z WINDOW...AS WELL
IFR CIGS AND VSBYS. TRIED TO TIME ONSET OF HEAVIEST SNOW...BUT IT
REALLY IS DEPENDENT ON THE DYNAMICS AND TRACK OF UPPER LEVEL LOW.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...WINTER WEATHER ADVISORY FROM NOON TODAY TO NOON CST TUESDAY FOR
SDZ060>069.
WINTER STORM WARNING FROM 9 AM THIS MORNING TO 9 AM CST TUESDAY
FOR SDZ070-071.
WINTER WEATHER ADVISORY FROM NOON TODAY TO 6 PM CST TUESDAY FOR
SDZ040-055-056.
WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 6 PM CST
TUESDAY FOR SDZ038-039-052>054-057>059.
MN...WINTER WEATHER ADVISORY FROM NOON TODAY TO 6 PM CST TUESDAY FOR
MNZ071.
WINTER STORM WARNING FROM NOON TODAY TO 6 PM CST TUESDAY FOR
MNZ072-080-081-089-090-097-098.
IA...WINTER STORM WARNING FROM 9 AM THIS MORNING TO 9 AM CST TUESDAY
FOR IAZ001>003-012>014-020>022-031-032.
NE...WINTER STORM WARNING FROM 9 AM THIS MORNING TO 9 AM CST TUESDAY
FOR NEZ013-014.
&&
$$
SHORT TERM...DUX
LONG TERM...
AVIATION...HEITKAMP
AREA FORECAST DISCUSSION
NWS MORRISTOWN TN
357 AM EST MON DEC 28 2015
.SHORT TERM (TODAY AND TONIGHT)...
ANOTHER MILD NIGHT ACROSS THE AREA WITH TEMPERATURES AT 3 AM STILL
IN THE 50S AND THE 60S. THE WARM FRONT APPEARS TO BE LOCATED JUST TO
THE NORTH OR NEAR THE NORTHERN PORTIONS OF THE FORECAST AREA.
DEWPOINTS IN KENTUCKY ARE CURRENTLY IN THE 40S WITH DEWPOINTS ACROSS
THE FORECAST AREA WELL INTO THE 50S AND 60S. WITH THIS
MOISTURE...THERE HAVE BEEN SOME REPORTS OF PATCHY DENSE FOG ACROSS
THE FORECAST AREA. NOT SEEING ANY WIDESPREAD ISSUES THIS MORNING SO
WILL MOST LIKELY CONTINUE WITH THE GOING SPS BUT WILL CONTINUE TO
MONITOR THINGS TO SEE IF AN ADVISORY WILL BE NEEDED.
CURRENT WATER VAPOR IMAGERY AND RAP UPPER AIR ANALYSIS INDICATE A
CLOSED LOW MOVING ACROSS EASTERN TEXAS WITH A RIDGE STILL IN PLACE
ACROSS THE WESTERN ATLANTIC. AT THE SURFACE...A LOW PRESSURE IS
LOCATED ACROSS THE ARKLAMISS WITH COLD FRONT STRETCHING SOUTHWARD
FROM THE LOW APPROACHING THE MISSISSIPPI RIVER. HIGH PRESSURE IS IN
PLACE ACROSS MUCH OF THE EASTERN U.S. FOR TODAY...THE SURFACE HIGH
WILL STRENGTHEN ACROSS THE NORTHEASTERN U.S. AS THE CLOSED UPPER LOW
PUSHES TO THE NORTHEAST INTO THE GREAT LAKES AROUND THE PERIPHERY OF
THE UPPER LEVEL RIDGE. THIS WILL CREATE SOUTHEASTERLY WINDS ACROSS
THE AREA TODAY. EXPECT THESE DOWNSLOPING WINDS WILL LEAD TO
TEMPERATURES IN THE 70S ACROSS THE VALLEY. THE ONLY EXCEPTION WILL
BE SOUTHWEST VIRGINIA AND NORTHEAST TENNESSEE WHERE MODELS INDICATE
SOME COLDER AIR MOVING IN LATE IN THE DAY WITH THE EASTERLY FLOW
AROUND THE HIGH. THIS SITUATION WILL LEAD TO A PINCHED OFF WARM
SECTOR AS THE COLD FRONT APPROACHES FROM THE WEST. THIS SETUP IS NOT
OVERLY FAVORABLE FOR STRONG OR SEVERE STORMS WITH THE WARM SECTOR
PINCHING OFF AND THE LOW RACING OFF TO THE NORTHEAST. WILL CONTINUE
WITH A SMALL MENTION OF STRONG TO POTENTIALLY SEVERE STORMS IN THE
HWO BUT THE THREAT IS MARGINAL AT BEST AND LIMITED TO THE FAR
SOUTHWESTERN COUNTIES.
THE MODELS INDICATE GOOD MOISTURE CONVERGENCE ALONG THE FRONT WITH
PW VALUES INCREASE TO AS HIGH AS 1.75 INCHES. THIS WOULD BE NEAR TO
ABOVE THE MAXIMUM PW VALUES OBSERVED FOR LATE DECEMEBER. DUE TO
THIS...EXPECT HEAVY RAINFALL WILL BE POSSIBLE ONCE AGAIN ACROSS THE
AREA. WITH THIS IN MIND...HAVE CONTINUED WITH THE FLOOD WATCH AND
HAVE EXTENDED IT SLIGHTLY TO THE NORTHEAST. MANY AREAS HAVE SEEN
EXCESSIVE RAINFALL OVER THE LAST WEEK AND AN ADDITIONAL 1-2 INCHES
OF RAIN SHOULD FALL MOSTLY AS RUNOFF. THE GOOD NEWS IS THAT THE
SYSTEM IS RATHER PROGRESSIVE AND EXPECT RAINFALL WILL COME TO AN END
LATE TONIGHT.
THE LOW LEVEL WINDS WITH THIS SYSTEM WILL ALSO POSE A PROBLEM. THE
PRESSURE GRADIENT WILL TIGHTEN AS THE COLD FRONTS MOVES WESTWARD
ACROSS TENNESSEE WITH A SURFACE HIGH ACROSS THE NORTHEASTERN U.S.
MODELS INDICATE THAT 850 MB WINDS WILL INCREASE TO 50-60 KTS. THESE
WINDS WILL BE PERPENDICULAR TO THE MOUNTAINS AND COULD LEAD TO A
MOUNTAIN WAVE SITUATION ACROSS THE FOOTHILLS. REGARDLESS...WIND
GUSTS AS HIGH AS 55 MPH WILL BE POSSIBLE ACROSS THE HIGH TERRAIN AND
THE FOOTHILLS. EXPECT THE VALLEY WILL EXPERIENCE WINDS OF 15-25 MPH
WITH GUSTS AS HIGH AS 40 MPH. THEREFORE...WENT WITH A WIND ADVISORY
THIS AFTERNOON INTO TONIGHT ACROSS THE ENTIRE AREA. IF MODELS TREND
UP SLIGHTLY...MAY HAVE TO UPGRADE THE ADVISORY TO A WARNING ACROSS
THE HIGHER TERRAIN.
.LONG TERM (TUESDAY THROUGH SUNDAY)...
SHOULD CONTINUE TO SEE A FEW LINGERING SHOWERS ACROSS THE AREA
TUESDAY MORNING AS MONDAY`S SYSTEM EXITS THE REGION. BUT
OVERALL...TUESDAY SHOULD BE MOSTLY DRY AND WILL SEE A BRIEF BREAK
IN PRECIP FOR MUCH OF TUESDAY AND TUESDAY EVENING. THE NEXT SYSTEM
OF CONCERN WILL BE A SHORT WAVE MOVING IN FROM THE SOUTH LATE
TUESDAY NIGHT INTO MAINLY WEDNESDAY. THIS WILL SPREAD SHOWERS
ACROSS THE AREA WITH A SLIGHT CHANCE OF THUNDERSTORMS OVER SOUTHERN
AREAS. MODELS ARE IN POOR AGREEMENT WITH THE TRACK OF THIS WAVE.
THE GFS CONTINUES TO BRING THE MAIN BAND OF SHOWERS ACROSS THE
CAROLINAS WHILE THE NAM IS TRENDING THE TRACK FURTHER WEST INTO
EAST TN...SO CONFIDENCE IS LOW. HOWEVER...DUE TO ABUNDANT RECENT
RAINFALL AND ADDITIONAL RAIN EXPECTED WITH THE MONDAY SYSTEM...ANY
ADDITIONAL PRECIP COULD CAUSE LOCALIZED FLOODING. THEREFORE...WILL
EXTENDED THE FLASH FLOOD WATCH THROUGH THURSDAY 12Z FOR SOUTHERN
AND EASTERN LOCATIONS. A FEW SHOWERS MAY LINGER OVER NORTHEAST AREA
INTO THURSDAY...AS THE WAVE PULLS OUT OF THE REGION. THEN...A
COOLER...DRIER AIR MASS WILL MOVE IN FOR THE REST OF THE EXTENDED.
&&
.PRELIMINARY POINT TEMPS/POPS...
CHATTANOOGA AIRPORT, TN 71 53 62 50 / 100 90 30 70
KNOXVILLE MCGHEE TYSON AIRPORT, TN 74 58 61 49 / 80 100 20 60
OAK RIDGE, TN 74 56 60 48 / 80 100 20 50
TRI CITIES AIRPORT, TN 68 49 59 46 / 60 90 40 60
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...FLASH FLOOD WATCH FROM 1 PM EST THIS AFTERNOON THROUGH THURSDAY
MORNING FOR CHEROKEE-CLAY.
WIND ADVISORY FROM 1 PM THIS AFTERNOON TO 7 AM EST TUESDAY FOR
CHEROKEE-CLAY.
TN...FLASH FLOOD WATCH FROM 1 PM EST /NOON CST/ THIS AFTERNOON
THROUGH THURSDAY MORNING FOR BLEDSOE-BLOUNT SMOKY MOUNTAINS-
BRADLEY-COCKE SMOKY MOUNTAINS-EAST POLK-HAMILTON-MARION-
MCMINN-MEIGS-NW BLOUNT-NORTH SEVIER-NORTHWEST COCKE-
NORTHWEST MONROE-RHEA-SEQUATCHIE-SEVIER SMOKY MOUNTAINS-
SOUTHEAST MONROE-WEST POLK.
WIND ADVISORY FROM 1 PM EST /NOON CST/ THIS AFTERNOON TO 7 AM
EST /6 AM CST/ TUESDAY FOR ANDERSON-BLEDSOE-BLOUNT SMOKY
MOUNTAINS-BRADLEY-CAMPBELL-CLAIBORNE-COCKE SMOKY MOUNTAINS-
EAST POLK-GRAINGER-HAMBLEN-HAMILTON-HANCOCK-HAWKINS-
JEFFERSON-JOHNSON-KNOX-LOUDON-MARION-MCMINN-MEIGS-MORGAN-NW
BLOUNT-NORTH SEVIER-NORTHWEST CARTER-NORTHWEST COCKE-
NORTHWEST GREENE-NORTHWEST MONROE-RHEA-ROANE-SCOTT TN-
SEQUATCHIE-SEVIER SMOKY MOUNTAINS-SOUTHEAST CARTER-
SOUTHEAST GREENE-SOUTHEAST MONROE-SULLIVAN-UNICOI-UNION-
WASHINGTON TN-WEST POLK.
FLASH FLOOD WATCH FROM 1 PM EST THIS AFTERNOON THROUGH LATE
TONIGHT FOR ANDERSON-CAMPBELL-LOUDON-MORGAN-ROANE-SCOTT TN.
VA...WIND ADVISORY FROM 1 PM THIS AFTERNOON TO 7 AM EST TUESDAY FOR
LEE-RUSSELL-SCOTT-WASHINGTON-WISE.
&&
$$
MA/MJB
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
347 AM CST MON DEC 28 2015
.TODAY AND TONIGHT...FORECAST CONFIDENCE MEDIUM.
MODELS ARE A LITTLE MORE IN LINE WITH THE SURFACE TRACK WITH THE GFS
STILL A LITTLE MORE SOUTH AND EAST. THE NAM IS SIMILAR TO THE ECMWF
BUT THE ECMWF IS A LITTLE FARTHER WEST LIKE THE HIGH RESOLUTION MESO
MODELS ESPECIALLY THE HRRR.
PRECIPITATION SHOULD REACH THE GROUND ALONG THE ILLINOIS BORDER AREA
AROUND 9AM CST AND REACH THE FOND DU LAC AND SHEBOYGAN AREAS JUST
AFTER 1 PM.
THIS WILL BE A VERY WET SYSTEM WITH PRECIPITABLE WATER VALUES UP
0.90 INCH BEING DRIVEN BY A 50 KNOT LOW LEVEL JET AHEAD OF A
COMPACT...OCCLUDING LOW PRESSURE SYSTEM. THERE WILL BE VERY STRONG
SYNOPTIC FORCING WITH THIS SYSTEM... WITH LAYER Q-VECTOR CONVERGENCE
OF 20 TO 50 UNITS AND VERY STRONG OMEGA DURING THE AFTERNOON
AND EARLY EVENING TIME PERIOD. WE ARE EXPECTING 0.50 TO 0.75 INCH OF
QPF/LIQUID PRECIP WITHIN 6 HOURS MONDAY AFTERNOON. THE BIG QUESTION
CONTINUES TO BE PRECIP TYPE.
ALTHOUGH THE GFS IS STILL COOLER WITH THE THERMAL PROFILES...MOST
MODELS ARE KEYING ON SLEET BEING THE BIGGEST FACTOR WITH THIS STORM
OVER THE FORECAST AREA...WITH FREEZING RAIN ALSO A CONCERN...EXCEPT
FAR EAST NEAR LAKE MICHIGAN WITH THE WARMER LAKE WATERS. FARTHER
WEST AND NORTH MORE OF A SNOW MIX IS EXPECTED. DUE TO EVAPORATIVE
COOLING MANY AREAS COULD SEE SOME SNOW INITIALLY.
AS THE LOW APPROACHES THE PRECIPITATION WILL TURN MORE RAIN IN THE
FAR SOUTHEAST...THEN A VARIETY OF DRIZZLE TYPES NEAR THE LOW. SOME
TRANSITION BACK TO LIGHT SNOW AS THE MID LEVEL LOW MOVES OVER.
STRONG EAST WINDS WILL FURTHER EXACERBATE TRAVEL CONDITIONS WITH
PERIODS OF WHITEOUT CONDITIONS IN THE MORE SNOW AREAS WEST OF
MADISON AND POTENTIAL IMPACTS FROM UP TO 0.10 TO 0.20 INCH OF
FREEZING RAIN. THUS A WINTER STORM WARNING CONTINUES FOR ALL OF
SOUTHERN AND EAST CENTRAL WISCONSIN.
GUSTY EAST WINDS WILL STEADILY INCREASE THIS MORNING AND BECOME VERY
STRONG BY MONDAY AFTERNOON. WIND GUSTS OF 40 TO 45 MPH
LIKELY...WITH SOME 50 MPH GUSTS POSSIBLE ESPECIALLY HIGH AREAS AND
NEAR LAKE MICHIGAN.
.TUESDAY - CONFIDENCE...MEDIUM
LINGERING MID LEVEL CYCLONIC FLOW AS FIRST WAVE LIFTS NORTHEAST FROM
SRN WI AND SECONDARY WAVE SHIFTS SLOWLY NE FROM SRN MN VCNTY. BY
AFTERNOON MID LEVEL FLOW EXPECTED TO BR BROADLY ANTICYCLONIC.
SFC/850 CONVERGENCE PERSISTS IN THE MORNING AS LOW WEAKENS FURTHER
AND SHIFTS NE AWAY FROM LWR MI VCNTY. CONVERGENCE WEAKENS DURG THE
AFTN AND SHIFTS NORTH AWAY FROM SRN WI. MODELS ARE ALL SHOWING
SOME LIGHT QPF PERSISTING DURG THE MRNG HRS. OF PARTICULAR CONCERN
IS THE MID LEVEL DRYING WHICH RESULTS IN THE LOSS OF SATURATION
WITHIN THE DENDRIDIC GROWTH ZONE. SO EXPECT SOME FREEZING DRIZZLE
IN THIS SCENARIO. HIGHEST POPS WILL BE IN THE MORNING WITH A SHIFT
TOWARDS CONFINING POPS TO THE THE NORTHERN REACHES OF THE CWA FOR
THE AFTN HRS. LLVL RH PROGS KEEP THINGS MOIST SO STAYING
PESSIMISTIC WRT CLOUD COVER.
.WEDNESDAY - CONFIDENCE...MEDIUM
ELONGATED VORT AXIS THEN PROGGD TO SHIFT NE FROM BASE OF WRN
TROUGH. NOT MUCH IN THE WAY OF A SFC REFLECTION TO THIS THOUGH A
SFC/850 TROUGH LIKELY TO AID IN SOME VERTICAL MOTION. QPF AMOUNTS
ARE LIGHT AND IN THIS CASE WE ARE SEEING ENOUGH SATURATION IN THAT
DENDRIDIC GROWTH ZONE TO GO WITH ALL SNOW ON THE PRECIP TYPE. SO
OVERALL LOOKS LIKE SOME AREAS SEE A 1/2 INCH OF SNOW.. THE GFS HAS
A SMIDGE HIGHER QPF THAT WOULD PERHAPS PUSH AN INCH BUT WILL GO
WITH MORE OF A CONSENSUS APPROACH WRT QPF AT THIS TIME.
.THURSDAY THROUGH SUNDAY - CONFIDENCE...MEDIUM
OVERALL QUIET NW FLOW REGIME. GFS SUGGESTS SOME SHSN POTENTIAL
FOR THU BUT ECMWF IS DRY AND SUPERBLEND POPS LEAN THIS WAY. MAY
NEED A SMALL POP OR SOME FLURRIES EVENTUALLY BUT FOR NOW WILL KEEP
THINGS DRY. 925 TEMPS SUPPORT HIGHS MOSTLY IN THE 20S TO LOW 30S.
&&
.AVIATION/12Z TAFS/...
.AVIATION/12Z TAFS/...THE EAST WINDS HAVE PUSHED AN MVFR CLOUD DECK
ACROSS MUCH OF SOUTHERN WISCONSIN DUE TO MOISTURE OFF LAKE MICHIGAN.
A STRONG LOW WILL MOVE ACROSS THE MID MISSISSIPPI VALLEY AND INTO
NORTHERN ILLINOIS THIS EVENING. PRECIPITATION WILL SPREAD NORTH.
INITIALLY DRY AIR WILL CAUSE VIRGA...BUT THE STRONG VERTICAL MOTION
WILL CAUSE PRECIPITATION TO REACH THE GROUND MID MORNING FAR SOUTH
AND TOWARDS NOON NEAR FOND DU LAC AND SHEBOYGAN. A WARM SURGE
AROUND 7 TO 9 THSD FT WILL CAUSE A MIX OF PRECIPITATION TO DEVELOP
WITH SLEET THE PREDOMINATE TYPE MOST AREAS. SOME FREEZING RAIN WILL
LATER THIS AFTERNOON INLAND AREAS. SNOW MAY FALL WITH THE ONSET AND
ALSO A MIX OF SNOW AND SLEET ESPECIALLY NORTH AND WEST OF
MADISON.
CIGS/VSBYS BECOMING IFR/LIFR THIS AFTERNOON AND EVENING.
NORTHEAST WINDS WILL VEER EAST...INCREASING TO 30 KNOTS MID-LATE
MORNING AND 40 KNOTS IN THE AFTERNOON...WITH 45 KNOT GUSTS IN THE
FAR EAST.
&&
.MARINE...WILL UPGRADE TO A STORM WARNING. HIGHEST STORM FORCE
GUSTS EXPECTED LATE AFTERNOON AND EARLY EVENING.
LATEST HIGH RESOLUTION HRRR EXPERIMENTAL SUPPORTS A HIGH-END GALE
WARNING...WITH STORM FORCE GUSTS LIKELY LATE AFTERNOON AND EARLY
EVENING. WILL OBVIOUSLY NEED A SMALL CRAFT ADVISORY FOR A TIME
OVERNIGHT MONDAY NIGHT AND TUESDAY AFTER THE GALE WARNING EXPIRES
AND THE LOW MOVES INTO SOUTHERN LAKE MICHIGAN DIMINISHING THE
WINDS.
&&
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...WINTER STORM WARNING FROM 9 AM THIS MORNING TO 6 AM CST TUESDAY
FOR WIZ062>072.
LAKESHORE FLOOD ADVISORY FROM 9 AM THIS MORNING TO MIDNIGHT CST
TONIGHT FOR WIZ052-060-066-071-072.
WINTER STORM WARNING FROM NOON TODAY TO 6 AM CST TUESDAY FOR
WIZ046-047-051-052-056>060.
LM...SMALL CRAFT ADVISORY UNTIL 6 AM CST EARLY THIS MORNING FOR
LMZ643>646.
STORM WARNING UNTIL 10 PM CST THIS EVENING FOR LMZ643>646.
&&
$$
TODAY/TONIGHT AND AVIATION/MARINE...HENTZ
TUESDAY THROUGH SUNDAY...COLLAR
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
315 AM CST MON DEC 28 2015
.TODAY AND TONIGHT...FORECAST CONFIDENCE MEDIUM.
MODELS ARE A LITTLE MORE IN LINE WITH THE SURFACE TRACK WITH THE GFS
STILL A LITTLE MORE SOUTH AND EAST. THE NAM IS SIMILAR TO THE ECMWF
BUT THE ECMWF IS A LITTLE FARTHER WEST LIKE THE HIGH RESOLUTION MESO
MODELS ESPECIALLY THE HRRR.
PRECIPITATION SHOULD REACH THE GROUND ALONG THE ILLINOIS BORDER AREA
AROUND 9AM CST AND REACH THE FOND DU LAC AND SHEBOYGAN AREAS JUST
AFTER 1 PM.
THIS WILL BE A VERY WET SYSTEM WITH PRECIPITABLE WATER VALUES UP
0.90 INCH BEING DRIVEN BY A 50 KNOT LOW LEVEL JET AHEAD OF A
COMPACT...OCCLUDING LOW PRESSURE SYSTEM. THERE WILL BE VERY STRONG
SYNOPTIC FORCING WITH THIS SYSTEM... WITH LAYER Q-VECTOR CONVERGENCE
OF 20 TO 50 UNITS AND VERY STRONG OMEGA DURING THE AFTERNOON
AND EARLY EVENING TIME PERIOD. WE ARE EXPECTING 0.50 TO 0.75 INCH OF
QPF/LIQUID PRECIP WITHIN 6 HOURS MONDAY AFTERNOON. THE BIG QUESTION
CONTINUES TO BE PRECIP TYPE.
ALTHOUGH THE GFS IS STILL COOLER WITH THE THERMAL PROFILES...MOST
MODELS ARE KEYING ON SLEET BEING THE BIGGEST FACTOR WITH THIS STORM
OVER THE FORECAST AREA...WITH FREEZING RAIN ALSO A CONCERN...EXCEPT
FAR EAST NEAR LAKE MICHIGAN WITH THE WARMER LAKE WATERS. FARTHER
WEST AND NORTH MORE OF A SNOW MIX IS EXPECTED. DUE TO EVAPORATIVE
COOLING MANY AREAS COULD SEE SOME SNOW INITIALLY.
AS THE LOW APPROACHES THE PRECIPITATION WILL TURN MORE RAIN IN THE
FAR SOUTHEAST...THEN A VARIETY OF DRIZZLE TYPES NEAR THE LOW. SOME
TRANSITION BACK TO LIGHT SNOW AS THE MID LEVEL LOW MOVES OVER.
STRONG EAST WINDS WILL FURTHER EXACERBATE TRAVEL CONDITIONS WITH
PERIODS OF WHITEOUT CONDITIONS IN THE MORE SNOW AREAS WEST OF
MADISON AND POTENTIAL IMPACTS FROM UP TO 0.10 TO 0.20 INCH OF
FREEZING RAIN. THUS A WINTER STORM WARNING CONTINUES FOR ALL OF
SOUTHERN AND EAST CENTRAL WISCONSIN.
GUSTY EAST WINDS WILL STEADILY INCREASE THIS MORNING AND BECOME VERY
STRONG BY MONDAY AFTERNOON. WIND GUSTS OF 40 TO 45 MPH
LIKELY...WITH SOME 50 MPH GUSTS POSSIBLE ESPECIALLY HIGH AREAS AND
NEAR LAKE MICHIGAN.
.TUESDAY - CONFIDENCE...MEDIUM
LINGERING MID LEVEL CYCLONIC FLOW AS FIRST WAVE LIFTS NORTHEAST FROM
SRN WI AND SECONDARY WAVE SHIFTS SLOWLY NE FROM SRN MN VCNTY. BY
AFTERNOON MID LEVEL FLOW EXPECTED TO BR BROADLY ANTICYCLONIC.
SFC/850 CONVERGENCE PERSISTS IN THE MORNING AS LOW WEAKENS FURTHER
AND SHIFTS NE AWAY FROM LWR MI VCNTY. CONVERGENCE WEAKENS DURG THE
AFTN AND SHIFTS NORTH AWAY FROM SRN WI. MODELS ARE ALL SHOWING
SOME LIGHT QPF PERSISTING DURG THE MRNG HRS. OF PARTICULAR CONCERN
IS THE MID LEVEL DRYING WHICH RESULTS IN THE LOSS OF SATURATION
WITHIN THE DENDRIDIC GROWTH ZONE. SO EXPECT SOME FREEZING DRIZZLE
IN THIS SCENARIO. HIGHEST POPS WILL BE IN THE MORNING WITH A SHIFT
TOWARDS CONFINING POPS TO THE THE NORTHERN REACHES OF THE CWA FOR
THE AFTN HRS. LLVL RH PROGS KEEP THINGS MOIST SO STAYING
PESSIMISTIC WRT CLOUD COVER.
.WEDNESDAY - CONFIDENCE...MEDIUM
ELONGATED VORT AXIS THEN PROGGD TO SHIFT NE FROM BASE OF WRN
TROUGH. NOT MUCH IN THE WAY OF A SFC REFLECTION TO THIS THOUGH A
SFC/850 TROUGH LIKELY TO AID IN SOME VERTICAL MOTION. QPF AMOUNTS
ARE LIGHT AND IN THIS CASE WE ARE SEEING ENOUGH SATURATION IN THAT
DENDRIDIC GROWTH ZONE TO GO WITH ALL SNOW ON THE PRECIP TYPE. SO
OVERALL LOOKS LIKE SOME AREAS SEE A 1/2 INCH OF SNOW.. THE GFS HAS
A SMIDGE HIGHER QPF THAT WOULD PERHAPS PUSH AN INCH BUT WILL GO
WITH MORE OF A CONSENSUS APPROACH WRT QPF AT THIS TIME.
.THURSDAY THROUGH SUNDAY - CONFIDENCE...MEDIUM
OVERALL QUIET NW FLOW REGIME. GFS SUGGESTS SOME SHSN POTENTIAL
FOR THU BUT ECMWF IS DRY AND SUPERBLEND POPS LEAN THIS WAY. MAY
NEED A SMALL POP OR SOME FLURRIES EVENTUALLY BUT FOR NOW WILL KEEP
THINGS DRY. 925 TEMPS SUPPORT HIGHS MOSTLY IN THE 20S TO LOW 30S.
&&
.AVIATION/12Z TAFS/...THE EAST WINDS HAVE PUSHED AN MVFR CLOUD DECK
ACROSS MUCH OF SOUTHERN WISCONSIN DUE TO MOISTURE OFF LAKE MICHIGAN.
A STRONG LOW WILL MOVE ACROSS THE MID MISSISSIPPI VALLEY AND INTO
NORTHERN ILLINOIS THIS EVENING. PRECIPITATION WILL SPREAD NORTH.
INITIALLY DRY AIR WILL CAUSE VIRGA...BUT THE STRONG VERTICAL MOTION
WILL CAUSE PRECIPITATION TO REACH THE GROUND MID MORNING FAR SOUTH
AND TOWARDS NOON NEAR FOND DU LAC AND SHEBOYGAN. A WARM SURGE
AROUND 7 TO 9 THSD FT WILL CAUSE A MIX OF PRECIPITATION TO DEVELOP
WITH SLEET THE PREDOMINATE TYPE MOST AREAS. SOME FREEZING RAIN WILL
LATER THIS AFTERNOON INLAND AREAS. SNOW MAY FALL WITH THE ONSET AND
ALSO A MIX OF SNOW AND SLEET ESPECIALLY NORTH AND WEST OF
MADISON.
CIGS/VSBYS BECOMING IFR/LIFR THIS AFTERNOON AND EVENING.
NORTHEAST WINDS WILL VEER EAST...INCREASING TO 30 KNOTS MID-LATE
MORNING AND 40 KNOTS IN THE AFTERNOON...WITH 45 KNOT GUSTS IN THE
FAR EAST.
&&
.MARINE...WILL UPGRADE SOUTH AREAS TO A STORM WARNING. HIGHEST STORM
FORCE GUSTS EXPECTED LATE AFTERNOON AND EARLY EVENING.
LATEST HIGH RESOLUTION HRRR EXPERIMENTAL SUPPORTS A HIGH-END GALE
WARNING...WITH STORM FORCE GUSTS LIKELY MAINLY MILWAUKEE SOUTH LATE
AFTERNOON AND EARLY EVENING. WILL OBVIOUSLY NEED A SMALL CRAFT
ADVISORY FOR A TIME OVERNIGHT MONDAY NIGHT AND TUESDAY AFTER THE
GALE WARNING EXPIRES AND THE LOW MOVES INTO SOUTHERN LAKE MICHIGAN
DIMINISHING THE WINDS.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...WINTER STORM WARNING FROM 9 AM THIS MORNING TO 6 AM CST TUESDAY
FOR WIZ062>072.
LAKESHORE FLOOD ADVISORY FROM 9 AM THIS MORNING TO MIDNIGHT CST
TONIGHT FOR WIZ052-060-066-071-072.
WINTER STORM WARNING FROM NOON TODAY TO 6 AM CST TUESDAY FOR
WIZ046-047-051-052-056>060.
LM...SMALL CRAFT ADVISORY UNTIL 6 AM CST EARLY THIS MORNING FOR
LMZ643>646.
STORM WARNING FROM 6 AM THIS MORNING TO 10 PM CST THIS EVENING
FOR LMZ645-646.
GALE WARNING FROM 6 AM THIS MORNING TO MIDNIGHT CST TONIGHT FOR
LMZ643-644.
&&
$$
TODAY/TONIGHT AND AVIATION/MARINE...HENTZ
TUESDAY THROUGH SUNDAY...COLLAR
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1155 PM CST SUN DEC 27 2015
UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND MONDAY
ISSUED AT 240 PM CST SUN DEC 27 2015
THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW ARCTIC HIGH
PRESSURE CENTERED OVER THE NORTHERN GREAT PLAINS AND SOUTH-CENTRAL
CANADA EARLY THIS AFTERNOON. NORTHWEST WINDS AROUND THE HIGH
CONTINUE TO BRING CLOUDS OFF LAKE SUPERIOR...WHILE STEEP LOW LEVEL
LAPSE RATES ARE HELPING TO FILL IN ANY HOLES THAT DEVELOP IN THE
CLOUD COVER. SKIES CLEAR OVER FAR WESTERN WISCONSIN AND MINNESOTA
CLOSER TO THE SURFACE HIGH. LOOKING TO THE FAR SOUTHWEST...UPPER
LEVEL LOW PRESSURE IS MOVING EAST OVER THE RIO GRANDE. AS THIS LOW
TRACKS INTO THE GREAT LAKES LATE MONDAY AND EARLY TUESDAY...IMPACTS
FROM WINTRY WEATHER ARE THE MAIN FORECAST CONCERNS.
TONIGHT...MAINLY QUIET. ARCTIC HIGH PRESSURE WILL SLIDE NORTH OF
LAKE SUPERIOR WITH WINDS VEERING FROM NORTH TO NORTHEAST THROUGH THE
NIGHT. STILL THINK WILL SEE A PERIOD OF CLEARING OVER NORTHEAST AND
CENTRAL WI AS LOW CLOUDS LOOK DIURNALLY ENHANCED AWAY FROM THE SNOW
BELTS. LOW INVERSION HEIGHTS THEN SUPPORT NORTHEAST WINDS BRINGING
IN LOW CLOUDS OFF LAKES MICHIGAN AND SUPERIOR OVERNIGHT. A FEW
FLURRIES COULD MOVE ACROSS ALONG THE LAKESHORE. LOWS FALLING INTO
THE SINGLE DIGITS NORTH TO MID 20S LAKESIDE.
MONDAY...UPPER LEVEL LOW PRESSURE WILL BE GRADUALLY MOVING NORTHWARD
FROM EASTERN TEXAS INTO THE MID-MISSISSIPPI VALLEY. TO THE
NORTH...EAST WINDS WILL CONTINUE TO FUNNEL IN ARCTIC AIR ACROSS THE
WESTERN GREAT LAKES REGION. IF FLURRIES DEVELOP...THEY SHOULD
CONTINUE THROUGH THE EARLY AFTERNOON HOURS. OTHERWISE...SKIES
SHOULD BE MAINLY MOSTLY CLOUDY THROUGH MIDDAY. FORCING AHEAD OF THE
UPPER LOW WILL INCREASE QUICKLY DURING THE AFTERNOON. COUPLED JET
STRUCTURE COMBINED WITH STRONG MID-LEVEL FGEN WILL BRING A SWATH OF
PRECIP INTO CENTRAL AND EAST-CENTRAL WISCONSIN AFTER ABOUT 20-21Z.
PROGGED SOUNDINGS INDICATE THAT SOME SLEET MAY WORK IN WITH THE SNOW
RIGHT AS PRECIP ARRIVES. DID REMOVE THE RAIN MENTION ALONG THE
LAKESHORE SINCE LOW LEVEL TEMPS ARE VERY COLD. DUE TO THE SNOW AND
SLEET MIX COMBINED WITH GUSTY EAST WINDS IN EXCESS OF 30-35
MPH...THE EVENING COMMUTE COULD BECOME QUITE HAZARDOUS. WILL
UPGRADE THE WATCH TO A WINTER STORM WARNING AND START THE HEADLINE
AT 21Z. COULD SEE UP TO AN INCH OF SNOW IN SPOTS BY 6 PM.
.LONG TERM...MONDAY NIGHT THROUGH SUNDAY
ISSUED AT 240 PM CST SUN DEC 27 2015
WINTER STORM IMPACTS IN NORTH-CENTRAL AND NORTHEAST WISCONSIN
WILL CONTINUE THROUGH MONDAY EVENING INTO TUESDAY MORNING...
TAPERING OFF OVERNIGHT. COMPUTER MODELS ARE IN RELATIVELY GOOD
AGREEMENT ON TRACK AND TIMING OF THE LOW PRESSURE SYSTEM CENTER
MOVEMENT INTO WISCONSIN...WHICH CONTINUES TO PLACE THE FOX VALLEY
IN A SLEET-TO-SNOW TRANSITION AREA. ON MONDAY EVENING...IN
ADDITION TO THE ONGOING WINTRY PRECIPITATION...EAST WINDS WILL
GUST IN THE 30-40 MPH RANGE NEAR LAKE MICHIGAN AND THE BAY TO
START OFF THE EVENING...WITH GUSTS TO 30 MPH ELSEWHERE ACROSS THE
REGION. WINDS WILL THEN TAPER OFF AS THE LOW PRESSURE SYSTEM
WEAKENS OVERNIGHT INTO TUESDAY MORNING. FLURRIES WILL LINGER A
LITTLE WHILE ACROSS THE AREA TUESDAY MORNING AS THE REMNANTS OF
THE SYSTEM DEPART TO THE EAST.
ANOTHER WEAKER SYSTEM WILL BRING A CHANCE OF LIGHT SNOW ON
WEDNESDAY INTO WEDNESDAY EVENING. TEMPERATURES BY THE END OF THE
WORK WEEK SHOULD FALL TO NORMAL OR EVEN A FEW DEGREES BELOW
NORMAL.
&&
.AVIATION...FOR 06Z TAF ISSUANCE
ISSUED AT 1153 PM CST SUN DEC 27 2015
NORTHEASTERLY WINDS OVERNIGHT WILL BRING SCT-BKN CLOUDS OFF LAKE
MICHIGAN INTO EASTERN WISCONSIN WHERE OCCASIONAL MVFR CIGS AND
FLURRIES ARE POSSIBLE. FURTHER TO THE WEST MAINLY VFR CONDITIONS
WITH A FEW AREAS OF MVFR CIGS OVERNIGHT.
THEN...A LARGE AND STRONG LOW PRESSURE SYSTEM WILL APPROACH THE
FORECAST AREA FROM THE CENTRAL MISSISSIPPI VALLEY DURING THE DAY
ON MONDAY. AS THIS SYSTEM APPROACHES...EAST TO NORTHEAST WINDS
WILL INCREASE DURING THE MORNING. BY EARLY TO MID-AFTERNOON MONDAY
WIND GUSTS OF 30 TO 35 MPH ARE LIKELY ESPECIALLY OVER THE FOX
VALLEY AND LAKE SHORE AREAS. THE GUSTY EAST TO NORTHEAST WINDS
WILL CONTINUE INTO THE EVENING HOURS. A LARGE PRECIPITATION
SHIELD WILL ALSO PUSH NORTHWARD DURING THE AFTERNOON REACHING THE
SOUTHERN FOX VALLEY BY AROUND 21 OR 22 UTC BRINGING IFR CONDITIONS.
A MIXTURE OF SNOW AND SLEET IS LIKELY...WITH ACCUMULATING
SNOW/SLEET BY THE END OF THE TAF PERIOD FROM GRB TO ISW SOUTHWARD.
MAINLY SNOW WILL QUICKLY SPREAD NORTH ACROSS THE ENTIRE FORECAST
AREA BY 03 UTC WITH WIDESPREAD IFR CONDITIONS. THE SNOW WILL BE
MIXED WITH SLEET OVER THE FOX VALLEY AND LAKESHORE.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING FROM 3 PM MONDAY TO 6 AM CST TUESDAY FOR
WIZ030-031-035>040-045-048>050.
WINTER STORM WARNING FROM 6 PM MONDAY TO 9 AM CST TUESDAY FOR
WIZ005-010>013-018>022-073-074.
&&
$$
SHORT TERM.....MPC
LONG TERM......ML
AVIATION.......ESB
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1017 PM MST SUN DEC 27 2015
.UPDATE...
ISSUED AT 551 PM MST SUN DEC 27 2015
TEMPERATURES ARE REALLY TANKING THIS AFTERNOON WITH SUNSET.
OBSERVED TEMPERATURES AT 00Z WERE WELL BELOW FORECAST TEMPERATURES
FOR THE SAME TIME...SOME AS MUCH AS 5-8 DEGREES. WENT AHEAD AND
ADJUSTED OVERNIGHT LOWS BASED ON THIS TREND. SEEING SOME LOCATIONS
OUT WEST WITH WINDCHILL TEMPERATURES CURRENTLY AT 20 TO 25 BELOW
ZERO. RAWLINS WAS -22 AND THE UPR SITE AT ROCK RIVER ALREADY AT
-33 WINDCHILL. DECIDED TO GO AHEAD WITH WINDCHILL WARNINGS OUT
WEST AND WINDCHILL ADVISORIES OVER THE PANHANDLE...VERY SIMILAR TO
LAST NIGHT. UPDATES HAVE BEEN SENT.
&&
.SHORT TERM...(TONIGHT-TUESDAY NIGHT)
ISSUED AT 225 PM MST SUN DEC 27 2015
TONIGHT...ARCTIC AIRMASS AND SNOW COVER MAKING FOR A DIFFICULT
TEMPERATURE FORECAST THIS AFTERNOON. 1 PM TEMPERATURES ONLY 2 AND 5
DEGREES RESPECTIVELY AT LARAMIE AND RAWLINS...AND STILL ONLY 7
DEGREES AT DOUGLAS AND CHADRON...WHILE TEENS PREVAIL ELSEWHERE.
ANOTHER TOUGH MINIMUM TEMPERATURE FORECAST TONIGHT JUST LIKE LAST
NIGHT. WITH COLD DAYTIME HIGH TEMPERATURES...MOSTLY CLEAR SKIES AND
LIGHT WINDS...AND SNOWPACK...ANOTHER COLD NIGHT ON TAP. WITH SOME
MINOR AIRMASS MODIFICATION...STILL EXPECT TO SEE LOWS TONIGHT SOME 5
TO 10 DEGREES WARMER THAN THIS MORNING...AND HAVE GONE CLOSER TO THE
COLDER GUIDANCE MINIMUMS.
MONDAY...SLOW WARMING TREND CONTINUES AS THE AIRMASS MODERATES
SLOWLY. INCREASING MID AND HIGH CLOUDS WILL LIMIT WARMING. WEAK LOW
LEVEL WIND FIELD WILL KEEP DOWNSLOPE FROM DEVELOPING AND PROVIDING
MORE WARMING. WILL STICK CLOSE TO GUIDANCE MAXIMUMS.
MONDAY NIGHT...SLIGHTLY WARMER THAN TONIGHT AS THE AIRMASS CONTINUES
TO SLOWLY MODERATE. PLUS...WE SHOULD HAVE SCATTERED TO BROKEN MID
AND HIGH CLOUDS.
TUESDAY...COLDER DAY AGAIN DUE TO INCREASING CLOUD COVER AND COLDER
TEMPERATURES ALOFT.
TUESDAY NIGHT...BROAD CYCLONIC FLOW ALOFT PREVAILS AND WITH ENOUGH
LOW AND MID LEVEL MOISTURE...EXPECT TO SEE OROGRAPHIC SNOWS OVER AND
NEAR THE SNOWY AND SIERRA MADRE RANGES. DRY ELSEWHERE. CLOUD COVER
WILL MAKE FOR A LITTLE BIT WARMER OVERNIGHT.
.LONG TERM...(WEDNESDAY-SUNDAY)
ISSUED AT 225 PM MST SUN DEC 27 2015
AN INVERTED SURFACE TROUGH COMBINED WITH LARGE SCALE TROUGHING IN
PLACE OVER THE WESTERN/CENTRAL CONUS MAY RESULT IN AREAS OF LIGHT
SNOW OVER THE HIGHER TERRAIN ON WEDNESDAY. AFTER THAT...THE MODELS
ARE IN GOOD AGREEMENT WITH A 1035+ MB SURFACE HIGH DOMINATING THE
CENTRAL ROCKIES LATE IN THE WEEK. A COLD/DRY AIR MASS WILL RESULT
IN MINIMAL CHANCES FOR PRECIPITATION THROUGH THE EXTENDED. EXPECT
CONTINUED COLD TEMPERATURES FOR THURSDAY/FRIDAY AS THE CORE OF H7
TEMPS AOB -15 DEG C MOVES OVER THE CWA. EVENTUAL SNOW DEPTHS WILL
PLAY A KEY ROLE IN SURFACE TEMPERATURES...BUT WE WILL CERTAINLY BE
LOOKING AT BITTERLY COLD WIND CHILLS FOR MUCH OF THE AREA. RIDGING
ALOFT AND WARMING THERMAL PROFILES MAY GET US ABOVE FREEZING AGAIN
BY SAT/SUN.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1014 PM MST SUN DEC 27 2015
VFR CONDITIONS EXPECTED ACROSS SOUTHEAST WYOMING AND NEBRASKA
PANHANDLE. HRRR HINTING AT SOME POSSIBLE FOG DEVELOPMENT HERE AT
KCYS AND THE SOUTHERN PANHANDLE. BUT WIND DIRECTION NOT FAVORABLE
AT KCYS AND AM NOT SEEING ANY DEVELOPMENT OVER THE PANHANDLE. SO I
DISREGARDED THE ITS SOLUTION. VERY COLD NEXT 24 HOURS AND BEYOND.
&&
.FIRE WEATHER...
ISSUED AT 225 PM MST SUN DEC 27 2015
NO CONCERNS BASED ON PROJECTED WINDS AND HUMIDITIES.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...WIND CHILL WARNING UNTIL 9 AM MST MONDAY FOR WYZ104-105-109>111-
115.
NE...WIND CHILL ADVISORY UNTIL 9 AM MST MONDAY FOR NEZ002-003-019>021-
054-055-095-096.
&&
$$
UPDATE...GCC
SHORT TERM...RUBIN
LONG TERM...CLH
AVIATION...GCC
FIRE WEATHER...RUBIN
AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
353 AM PST MON DEC 28 2015
.SYNOPSIS...
A COLD LOW PRESSURE SYSTEM FROM THE NORTHWEST WILL BRING A PERIOD OF
OF SHOWERS...MAINLY DURING THE AFTERNOON AND EVENING...AND LOCALLY GUSTY
WEST WINDS IN THE MOUNTAINS AND DESERTS. FOR TUESDAY THROUGH THURSDAY...
DRY WITH A GRADUAL WARMING TREND TO A LITTLE BELOW AVERAGE ALONG WITH
PERIODS OF MOSTLY WEAK OFFSHORE FLOW. SLIGHTLY COOLER FOR FRIDAY AND
SATURDAY...THEN A LITTLE WARMER FOR SUNDAY. A STRONGER AND VERY WET
PACIFIC STORM SYSTEM IS POSSIBLE LATE SUNDAY NIGHT AND MONDAY.
&&
.PREVIOUS DISCUSSION (ISSUED 120 PM PST)...FOR EXTREME SOUTHWESTERN
CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND
SOUTHWESTERN SAN BERNARDINO COUNTIES...
DRY THROUGH THIS MORNING. A COLD LOW PRESSURE SYSTEM FROM THE
NORTHWEST WILL BRING A PERIOD OF SHOWERS...MAINLY IN THE AFTERNOON
AND EVENING...WITH GUSTY WEST WINDS IN THE MOUNTAINS AND DESERTS.
BASED ON 850 TO 500 MB MOST UNSTABLE CAPE VALUES AND THE AXIS OF
THE COLDEST MID LEVEL AIR...A SLIGHT CHANCE OF THUNDERSTORMS HAS
BEEN ADDED FOR LATE THIS AFTERNOON AND EARLY THIS EVENING. THE
GREATEST AND MOST WIDESPREAD PRECIPITATION AMOUNTS ARE EXPECTED
ACROSS SAN DIEGO COUNTY WITH LESS TO THE NORTH. GENERAL RAINFALL
AMOUNTS ARE EXPECTED TO RANGE FROM ONE TENTH INCH OR LESS NORTH TO
ONE QUARTER TO LOCALLY ONE THIRD INCH SOUTH. SHOWERS WILL END LATE
TONIGHT OVER FAR SOUTHERN PORTIONS OF SAN DIEGO COUNTY. A SNOW
LEVEL NEAR 4000 FEET WILL LOWER TO 3000 TO 3500 FEET TONIGHT. IT
IS POSSIBLE THERE COULD BE SOME GRAUPEL OR SMALL HAIL WITH SOME OF
THE SHOWERS DURING THE EARLY EVENING.
CONTINUED COLD NIGHTS THROUGH MID WEEK WITH SLOWLY WARMING DAYTIME
TEMPERATURES TO SLIGHTLY BELOW AVERAGE FOR TUESDAY THROUGH
THURSDAY. THERE WILL ALSO BE WEAK OFFSHORE FLOW DURING THIS
PERIOD.
SLIGHTLY COOLER FOR FRIDAY AND SATURDAY WITH A WEAK LOW PRESSURE
SYSTEM TO THE NORTH...THEN A LITTLE WARMER ON SUNDAY WITH HIGH
PRESSURE ALOFT IN ADVANCE OF THE FIRST OF A SERIES OF PACIFIC
STORMS.
THE GLOBAL MODELS CONTINUE TO ADVERTISE A SHIFT IN THE PATTERN
EARLY NEXT WEEK AS A STRONG LOW LATITUDE JET STREAM ACROSS THE
WESTERN AND CENTRAL PACIFIC UNDERCUTS BLOCKING HIGH PRESSURE AT
HIGHER LATITUDES NEAR THE WEST COAST. THIS WOULD BRING A SERIES OF
STORMS INTO CALIFORNIA. WHILE THERE ARE STILL SOME RUN TO RUN AND
MODEL TO MODEL DIFFERENCES...THE FIRST STORM WOULD ARRIVE INTO
SOUTHERN CALIFORNIA LATE SUNDAY NIGHT OR MONDAY WITH SOME SHOWERS
FOR TUESDAY...THEN ANOTHER STORM FOR WEDNESDAY. CURRENT GUIDANCE
CONTINUES TO BE A LITTLE STRONGER WITH THE MONDAY STORM THAN THE
WEDNESDAY STORM. THAT MONDAY STORM COULD BRING WIDESPREAD
STRONG GUSTY WINDS...HEAVY RAINFALL AT LOWER ELEVATIONS...AND
HEAVY SNOWFALL IN THE MOUNTAINS.
&&
.AVIATION...
281000Z...HIGH CLOUDS AOA 20000 FEET MSL WILL DRIFT BY THIS MORNING.
LOWER CLOUDS WILL GRADUALLY DEVELOP AND THICKEN DURING THE DAY WEST
OF THE MOUNTAINS WITH BASES AROUND 3000 FEET MSL. SHOWERS WILL
FOLLOW LATE THIS AFTERNOON AND EVENING...WHICH COULD BRIEFLY DROP
BASES TO AROUND 2000 FEET MSL BETWEEN 21-06Z. THERE IS ALSO A SLIGHT
CHANCE OF THUNDERSTORMS BETWEEN 22-04Z. THIS WILL ALSO OBSCURE SOME
AREAS IN THE MOUNTAINS. SCATTER OUT FROM NORTHWEST TO SOUTHEAST WILL
OCCUR TONIGHT.
&&
.MARINE...
200 AM...BRISK NORTHWEST WINDS WILL DEVELOP THIS AFTERNOON AND
NORTHWEST SWELL WILL INCREASE TONIGHT. THE COMBINATION OF WINDS AND
SEAS WILL CREATE HAZARDOUS BOATING CONDITIONS THIS AFTERNOON THROUGH
TONIGHT. THE SMALL CRAFT ADVISORY CONTAINS THE DETAILS...LAXMWWSGX.
IN ADDITION...THERE IS A SLIGHT CHANCE OF THUNDERSTORMS THIS
AFTERNOON AND EVENING. NO HAZARDOUS MARINE WEATHER IS EXPECTED
TUESDAY THROUGH FRIDAY.
&&
.SKYWARN...
SKYWARN ACTIVATION IS NOT REQUESTED. HOWEVER WEATHER SPOTTERS ARE
ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...
CA...FROST ADVISORY UNTIL 8 AM PST THIS MORNING FOR COACHELLA VALLEY-
SAN BERNARDINO AND RIVERSIDE COUNTY VALLEYS-THE INLAND
EMPIRE-SAN DIEGO COUNTY DESERTS-SAN DIEGO COUNTY VALLEYS-
SAN GORGONIO PASS NEAR BANNING.
PZ...SMALL CRAFT ADVISORY FROM 1 PM THIS AFTERNOON TO 4 AM PST
TUESDAY FOR WATERS FROM SAN MATEO POINT TO THE MEXICAN
BORDER EXTENDING 30 TO 60 NM OUT INCLUDING SAN CLEMENTE
ISLAND.
SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 4 AM PST TUESDAY
FOR COASTAL WATERS FROM SAN MATEO POINT TO THE MEXICAN
BORDER AND OUT TO 30 NM.
&&
$$
PUBLIC...17
AVIATION/MARINE...MM
[top]
Area Forecast Discussion
National Weather Service Sacramento CA
330 AM PST MON DEC 28 2015
.Synopsis...
A cold weather system with low snow levels but limited moisture
will impact interior Northern California today. Another weak
system Tuesday night into Wednesday, otherwise mainly dry weather
for the week ahead.
&&
.Discussion...
Stronger short-wave associated with the digging upper trough
moving across NorCal early this morning presently resulting in a
band of showers extending from the northern Sierra southwestward
to south of the Bay Area. Amounts have been very light along this
band - only a few hundredths of an inch. Temperatures through the
valley mostly range from the mid 30s to lower 40s.
The main shower band is expected to move pretty quickly to the
south of the area this morning as the upper trough digs toward
SoCal limiting potential impacts. Only some lingering snow
showers are forecast along the northern Sierra Crest for the
afternoon. The area of showers presently over Cape Mendocino is
forecast by the HRRR to continue moving southward and weaken
offshore the Bay Area by midday.
Mainly dry weather with coolish temperatures is expected the
remainder of the year. However, another weak system is forecast
to drop down in northwesterly flow Tuesday night and Wednesday
bringing a few showers to the region, but it too will be
relatively moisture starved, so only light QPF expected.
&&
.Extended Discussion (Friday through Monday)...
Dry weather for Friday and the weekend. Models depicting weak low
across West Coast but little impact expected on the region.
Temperatures will be be within a degree or two of normal. Next
chance for precipitation might arrive Monday with a pattern shift
but model differences are fairly large. CEO
&&
.Aviation...
Brief period of MVFR conditions this morning as weak weather
system moves through with rain and snow showers. Snow levels below
1000 feet north to 2000 feet across the northern Sierra Nevada.
Otherwise VFR conditions will rule with winds 10 kts or below for
TAF sites.
&&
.STO Watches/Warnings/Advisories...None.
&&
$$
AREA FORECAST DISCUSSION
NWS SAN JOAQUIN VALLEY - HANFORD CA
315 AM PST MON DEC 28 2015
.SYNOPSIS...
A WEATHER DISTURBANCE WILL BRING AN INCREASE OF CLOUDS AND
PRECIPITATION TO CENTRAL CALIFORNIA TODAY. THE BEST CHANCES FOR
PRECIPITATION WILL BE IN THE NORTHERN SIERRA NEVADA WITH SCATTERED
SHOWERS AND BREEZY CONDITIONS ELSEWHERE. DRY CONDITIONS WILL
RETURN TO THE REGION ON TUESDAY.
&&
.DISCUSSION...
PRECIPITATION CONTINUES TO ROLL INTO THE CENTRAL CALIFORNIA
INTERIOR THIS MORNING FROM A DEEP TROF MOVING THROUGH LATER TODAY.
WHILE DYNAMICS ARE ADEQUATE FOR IMPRESSIVE PRECIPITATION...THE
LACK OF MOISTURE WILL KEEP RAIN/SNOW AMOUNTS IN THE LIGHT TO
MODERATE CATEGORY. THIS LACK OF MOISTURE IS REFLECTED IN THE VERY
LOW PRECIP-WATER VALUES AS SEEN IN THE OAKLAND UPPER AIR
OBSERVATION. MODELS DO HAVE A GOOD HANDLE ON THE PRECIP RATES AS
THE HRRR IS SHOWING PRECIP ACCUM OF ONE TENTHS TO TWO TENTHS OVER
THE VALLEY WITH LOCALS VALUES OF A QUARTER OF AN INCH OVER THE
SIERRA NEVADA. IN ADDITION...THIS IS A FAST MOVING SYSTEM WITH
MOST OF THE PRECIP ENDING BEFORE 4 AM PST ON TUESDAY.
THIS FAST MOVING SYSTEM WILL INTRODUCE ANOTHER SHOT OF COLD AIR
INTO THE REGION. THE TROF AXIS WILL MOVE INTO ARIZONA BY TUESDAY
MORNING. AT THAT TIME...THE LONG FETCH OF A NORTHERLY WIND WILL
EXIST OVER THE REGION. THIS FETCH WILL ALLOW FOR VERY COLD AIR TO
FILTER INTO THE DISTRICT FOR A CONTINUATION OF FREEZING OVERNIGHT
TEMPERATURES. BY WEDNESDAY...WHILE NOT A TRUE NORTHERLY WIND FLOW
...THE FLOW REMAINS IN A NORTHWESTERLY DIRECTION FOR MODIFIED COLD
AIR. THEREFORE...WILL SEE NEAR FREEZING CONDITIONS FOR MOST OF
THIS WEEK. ON WEDNESDAY...MODELS SHOW A VERY WEAK SHORT-WAVE TROF
MOVING THROUGH THE GREAT BASIN AS A INSIDE-SLIDER. WHILE SHOWING
NO PRECIP...THIS SYSTEM MAY ALLOW FOR SOME MIXING OF THE
ATMOSPHERE FOR LESS FOG POTENTIAL.
THURSDAY WILL SEE THE START OF A BLOCKING PATTERN MOVE ONTO THE
WEST COAST. MODELS SHOW THIS BLOCKING TO REMAIN IN PLACE THROUGH
AT LEAST SUNDAY. THE END OF THE FORECAST PERIOD IS SHOWING AN
INTERESTING CHANGE IN THE WEATHER AS A TROF ATTEMPTS TO DIG AND
UNDER CUT THE BLOCKING PATTERN OVER THE WEST COAST. WHILE
CERTAINTY IS LOW FOR THIS DAY 8 EVENT...A FAIR NUMBER OF MODELS
ATTEMPT TO FORM THE TROF AND PUSH IT TOWARD THE WEST COAST. WILL
OPT FOR THE MONDAY SOLUTION AND INTRODUCE A PROBABILITY OF PRECIP
FOR SUNDAY NIGHT INTO MONDAY.
&&
.AVIATION...
A SYSTEM TO IMPACT MOUNTAINS EARLY MONDAY WITH OBSCURATIONS AND
PRECIPITATION DEVELOPING...ESPECIALLY WESTERN SIDE OF SIERRA
RANGE. IN THE MEANWHILE...FOG WILL ALLOW FOR AREAS OF IFR
CONDITIONS WITH PATCHES OF LIFR THROUGH 18Z TODAY.
&&
.AIR QUALITY ISSUES...
ON MONDAY DECEMBER 28 2015...FIREPLACE/WOOD STOVE BURNING STATUS
IS: NO BURNING UNLESS REGISTERED IN FRESNO...KERN AND MADERA
COUNTIES. FURTHER INFORMATION IS AVAILABLE AT VALLEYAIR.ORG
&&
.CERTAINTY...
THE LEVEL OF CERTAINTY FOR DAYS 1 AND 2 IS HIGH.
THE LEVEL OF CERTAINTY FOR DAYS 3 THROUGH 7 IS MEDIUM.
CERTAINTY LEVELS INCLUDE LOW...MEDIUM...AND HIGH. PLEASE VISIT
WWW.WEATHER.GOV/HNX/CERTAINTY.PHP /ALL LOWER CASE/ FOR ADDITIONAL
INFORMATION AND/OR TO PROVIDE FEEDBACK.
&&
.CLIMATE...
RECORDS
SITE DATE HI_MAX:YEAR LO_MAX:YEAR HI_MIN:YEAR LO_MIN:YEAR
KFAT 12-28 66:1945 35:1908 54:1977 24:1962
KFAT 12-29 69:1949 36:1908 54:1977 24:1990
KFAT 12-30 67:2013 36:1902 54:2001 24:1969
KBFL 12-28 73:1977 40:1908 58:1977 24:1930
KBFL 12-29 73:1956 40:1929 57:1977 22:1929
KBFL 12-30 74:1904 44:2014 53:1981 15:1905
&&
.HNX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
PUBLIC...MOLINA
AVN/FW...DCH
SYNOPSIS...MOLINA
WEATHER.GOV/HANFORD
AREA FORECAST DISCUSSION
NWS RENO NV
300 AM PST MON DEC 28 2015
.SYNOPSIS...
A COLD LOW PRESSURE SYSTEM WILL BRING SNOW SHOWERS TODAY. A
SECOND SYSTEM MAY PRODUCE LIGHT SNOW ON WEDNESDAY FOR AREAS NORTH
OF SUSANVILLE AND LOVELOCK. VALLEY INVERSIONS WILL DEVELOP LATE
THIS WEEK AS HIGH PRESSURE BUILDS OVERHEAD. SYSTEMS MAY BEGIN TO
UNDERCUT THE UPPER RIDGE EARLY NEXT WEEK FOR RENEWED CHANCES OF
PRECIPITATION.
&&
.SHORT TERM...
BEEFED UP WINDS FOR ALPINE/MONO RIDGES THIS MORNING AND AFTERNOON
WINDS FOR LAKE TAHOE AND PYRAMID LAKE, OTHERWISE MINIMAL CHANGES
TO THE SHORT TERM FORECAST.
LOW PRESSURE (EVIDENT IN WATER VAPOR SATELLITE) CENTERED OVER EXTREME
NORTHWEST CALIFORNIA WILL MOVE TO NEAR TAHOE BY LATE THIS MORNING.
LOOKING AT THE CURRENT INFRARED SATELLITE, THE INITIAL RAIN (BELOW
ABOUT 2000 FT) AND SNOW BAND OVER NORTHERN CALIFORNIA IS SLOWLY
ADVANCING INTO THE NORTHERN SIERRA AND GETTING ENHANCED BY DEFORMATION
JUST AHEAD OF THE UPPER LOW.
THIS MORNING, THE UPPER LOW CORE IS PROGGED TO DROP SOUTH TO NEAR
OR JUST WEST OF THE TAHOE CREST. THIS IS EXPECTED TO PUT WESTERN
NEVADA IN A FAVORABLE SPOT FOR DEFORMATION AND A PERIOD OF LIGHT
SNOW. IN FACT, THE LATEST RADAR SHOWS INDICATIONS OF LOWERING
CLOUD DECKS AND SOME VERY LIGHT SNOW BETWEEN RENO AND FALLON. WITH
THE SYSTEM BEING OF A SLIDER VARIETY, THE SIERRA IS NOT EXPECTED
TO GET MORE THAN A FEW INCHES OF SNOWFALL GIVEN THAT OROGRAPHIC
ENHANCEMENT WILL WANE THIS MORNING AS THE LOW DROPS OVERHEAD AND
LOW TO MID-LEVELS WINDS TURN NORTHERLY.
AS FAR AS TIMING FOR WIDESPREAD LIGHT SNOW BETWEEN RENO AND
LOVELOCK/FALLON, THE 09Z HRRR AND 06Z NAM INDICATE BETWEEN 4 AND 7 AM.
FROM A PATTERN RECOGNITION STANDPOINT, THIS MAKES SENSE AS WRAP-
AROUND/DEFORMATION SNOW WITH THIS TYPE OF SYSTEM OFTEN BREAKS OUT
AS THE LOW DROPS TO NEAR AND JUST SOUTH OF THE LATITUDE OF THE
AFFECTED AREA. WITH ROAD TEMPERATURES PLENTY COLD THIS MORNING,
WIDESPREAD LIGHT SNOW AND SNOW SHOWERS THIS MORNING COULD MAKE FOR
A SLICK COMMUTE FOR UNTREATED ROADS IN THE RENO-CARSON CITY AREA
THIS MORNING SO THE WINTER WEATHER ADVISORY WILL BE ALLOWED TO
CONTINUE.
AS FAR AS MINERAL AND SOUTHERN LYON COUNTIES, THE ADVISORY IS IN
MORE QUESTION AS SNOW DOES NOT LOOK TO START IN A WIDESPREAD
FASHION UNTIL AS LATE AS 8-10 AM. THE LATER IT STARTS THE LESS
LIKELY THAT THERE WILL BE SIGNIFICANT ROAD IMPACTS FOR LOWER
ELEVATION ROADS. STILL, HIGHER ROADS/PASSES SUCH AS SWEETWATER AND
ANCHORITE SUMMITS AND LUCKY BOY PASS COULD SEE SLICK CONDITIONS
BY LATE MORNING.
THIS AFTERNOON, THE FOCUS FOR SNOW SHOWERS SHIFTS INTO MONO AND
MINERAL COUNTIES AS THE DEFORMATION ZONE REACHES THAT AREA.
PRECIPITATION AMOUNTS SHOULD REMAIN LIGHT WITH UP TO A COUPLE
INCHES OF SNOWFALL POSSIBLE, BRINGING THE THREAT FOR ROAD CONTROLS
IN THE HIGHER ELEVATIONS.
TONIGHT THROUGH TUESDAY, THE SIERRA AND WESTERN NEVADA WILL BE
UNDER NORTHWEST FLOW ALOFT. THIS FLOW DOES NOT OFFER LONG PERIODS
OF CLEAR SKIES SO LOW TEMPERATURES WILL BE MODIFIED SOMEWHAT
(MAINLY TEENS TO AROUND 20 IN THE LOWER VALLEYS), ALTHOUGH CLOUDS
WILL HELP TO KEEP AFTERNOON TEMPERATURES CHILLY. LATE TUESDAY
NIGHT AND WEDNESDAY COULD BRING A WEAK SYSTEM INTO FAR NORTHERN
CALIFORNIA AND NEVADA FOR A CHANCE OF LIGHT SNOW SHOWERS,
GENERALLY NORTH OF SUSANVILLE AND GERLACH. SNYDER
.LONG TERM...THURSDAY THROUGH SUNDAY...
MINOR CHANGES WERE MADE TO THE EXTENDED FORECAST TODAY TO LOWER
TEMPS A LITTLE MORE FOR MOST OF THE PERIOD...BUT OVERALL THE MODEL
SOLUTIONS REMAIN MUCH AS THEY WERE 12-24 HOURS AGO.
A BROAD RESIDUAL TROUGH OVER THE INTERMOUNTAIN WEST, ORIENTED
EAST TO WEST, IS IN PLACE AT THE START OF THE PERIOD. LOW LEVEL
NORTH TO NORTHEAST FLOW WILL KEEP TEMPS BELOW AVERAGE THROUGH AT
LEAST FRIDAY.
MODEL SOLUTIONS ARE A BIT AT ODDS WITH HOW TO EVOLVE THIS TROUGH AS
THE ECMWF STILL WANTS TO DEVELOP A CLOSED LOW ALONG THE OREGON
BORDER WHILE THE OPERATIONAL GFS DEVELOPS THIS CLOSED LOW OVER
EASTERN AND CENTRAL NEVADA AND DRIFTS IT TO THE WEST NORTHWEST
THROUGH SATURDAY. MOST OF THE GEFS ENSEMBLE MEMBERS HAVE SOLUTIONS
CLOSER TO THE OPERATIONAL GFS. NONE OF THE MODELS PRODUCE MUCH IN
THE WAY OF PRECIPITATION WITH THIS LOW. IT JUST LOCKS THE LOW TO MID
LEVEL EAST TO NORTHEAST FLOW INTO MOST OF THE AREA WITH BELOW NORMAL
TEMPERATURES. SO WE HAVE LEFT THE FORECAST DRY BUT LOWERED HIGH AND
LOW TEMPERATURES A FEW DEGREES FOR LATE THIS WEEK INTO THE WEEKEND.
LATE IN THE FORECAST PERIOD THE MODELS ARE TRYING TO LIFT THE LOW
OUT AND DEVELOP MORE OF A SOUTHWEST FLOW ALOFT. THIS IS IN RESPONSE
TO A BROAD TROUGH MOVING TOWARD THE CA COAST. THIS TROUGH IS SHOWN
CUTTING UNDER THE BROAD SCALE FLOW OVER THE REGION AND DRIVING A WET
SYSTEM INTO CENTRAL AND SOUTHERN CA BY EARLY NEXT WEEK. THE TRACK OF
THIS SYSTEM IS STILL VERY UNCERTAIN...BUT COULD BRING APPRECIABLE
SNOW TO THE CENTRAL AND SOUTHERN SIERRA. THE FORECAST FOR THIS
SYSTEM IS VERY LOW CONFIDENCE AT THIS TIME. 20
&&
.AVIATION...
AN ELONGATED AREA OF LOW PRESSURE IS MOVING INTO NORTHERN AND
CENTRAL CA AT THIS TIME. THIS LOW PRESSURE IS NOT VERY STRONG BUT IS
PRODUCING LIGHT PRECIPITATION FROM NORTHERN CA SOUTH INTO THE
CENTRAL VALLEY AND INTO THE NORTHERN SIERRA. LIGHT SNOW IS LIKELY
THROUGH THE MORNING HOURS THROUGH THE SIERRA. THIS COULD RESULT IN
PERIODS OF IFR CIGS/VSBYS THROUGH ABOUT 28/22UTC AND ACCUMULATIONS
UP TO 2 INCHES AT KTVL AND KTRK TODAY. MOUNTAIN OBSCURATIONS ARE
ALSO LIKELY.
EAST OF THE SIERRA AND ACROSS NORTHEAST CA AMOUNTS WILL BE LESS.
LIGHT SNOW IS POSSIBLE NORTH OF PORTOLA AND GERLACH EARLY THIS
MORNING MOVING SOUTH TO AROUND THE I-80 CORRIDOR IN WESTERN NEVADA
BY AROUND DAYBREAK. CURRENT INDICATIONS ARE SNOW WOULD DEVELOP SOUTH
OF HIGHWAY 50 AFTER ABOUT 6-8 AM THIS MORNING. OVERALL UP TO AN INCH
OF SNOW IS POSSIBLE AT KRNO AND KCXP. PERIODS OF MVFR ARE LIKELY
EAST OF THE SIERRA TODAY WITH BRIEF PERIODS OF IFR IN SNOW SHOWERS.
SURFACE WINDS SHOULD REMAIN FAIRLY LIGHT TODAY AND GUSTS OVER THE
SIERRA WILL BE AROUND 30-35 KTS.
DRIER WEATHER DEVELOPS FOR TUESDAY THEN ANOTHER FAST MOVING SYSTEM
BRINGS LIGHT SNOW TO AREAS NORTH OF A LINE FROM SUSANVILLE TO
LOVELOCK FROM LATE TUESDAY NIGHT INTO WEDNESDAY. 20
&&
.REV WATCHES/WARNINGS/ADVISORIES...
NV...WINTER WEATHER ADVISORY UNTIL NOON PST TODAY NVZ003-004.
WINTER WEATHER ADVISORY UNTIL NOON PST TODAY NVZ001.
CA...NONE.
&&
$$
FOR MORE INFORMATION FROM THE NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/RENO (ALL LOWER CASE)
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
806 AM CST MON DEC 28 2015
.SHORT TERM...
401 AM CST
THROUGH TUESDAY...
A MAJOR WIND AND ICE EVENT FOR A GOOD PORTION OF THE AREA...ALONG
WITH SOME OTHER ACCOMPANYING IMPACTS...IS BEGINNING TO UNFOLD INTO
THE REGION EARLY THIS MORNING. NO CHANGES PLANNED TO THE SPATIAL
EXTENT OF THE CURRENT MYRIAD OF HEADLINES...AS THEY COVER THIS
DYNAMIC SYSTEM WELL...WITH JUST SOME MINOR SHIFTS TO TIMING TO
COVER PRIME THREAT TIMES. WE ARE AT THE STAGE NOW OF INCORPORATING
OBSERVATIONAL TRENDS INTO THE GOING FORECAST WITH HOPEFULLY
ADJUSTMENTS MORE SO THAN MAJOR SHIFTS...AND THUS FAR THAT IS THE
CASE. HOWEVER BEING IN A TRANSITIONAL PRECIPITATION EVENT WHERE
SPECIFIC SURFACE AND ALOFT TEMPERATURES PLAY CRITICAL ROLES MAKES
THIS PARTICULARLY CHALLENGING.
THE MOST NOTEWORTHY CHANGES/OBSERVATIONS IN SUMMARY ARE THE OVERALL
FORECAST PRECIPITATION AMOUNTS HAVE BEEN INCREASED AREAWIDE LATE
MORNING THROUGH THE AFTERNOON AS IT IS MORE APPARENT CONVECTIVE
ELEMENTS AND SLANTWISE INSTABILITY WILL IMPINGE INTO THE AREA. THE
OVERLAP AREA OF THESE HEAVIER INTENSITY/AMOUNTS AND THE STILL COLD
ENOUGH FOR FREEZING RAIN APPEARS TO BE ALONG/NORTH OF INTERSTATE
80 AND ALONG AND WEST OF ILLINOIS 47...SO HAVE BUMPED UP FORECAST
ICE ACCUMULATIONS IN THESE AREAS AND PLACED HEAVY WORDING IN THE
FORECAST. HAVE ALSO ADDED ISOLATED/SCATTERED THUNDER...ALTHOUGH
THAT SHOULD BE MAINLY AFTER THE PEAK ICING TIME.
ALSO CONTINUED AN ADJUSTMENT OF A BIT SLOWER TEMPERATURE RECOVERY
IN THE IMMEDIATE LOW-LEVELS RESULTING IN LONGER SLEET DURATION
ALONG AND NORTH OF I-88...WITH THAT POTENTIALLY THE DOMINANT
PRECIPITATION TYPE MOST OF THE MORNING IN THAT REGION. HAVE UPPED
SLEET ACCUMULATION TO AROUND AN INCH THOUGH HIGHER TOTALS
CERTAINLY POSSIBLE DEPENDING ON RATE. WHILE IMPACTS DURING THE
MORNING MAY BE LESS IF THIS MAINLY SLEET/INTERMITTENT SNOW
MATERIALIZES...THE ICING POTENTIAL IN THE AFTERNOON WITH STRONG
WINDS STILL LOOKS ON TRACK.
A VERY POTENT SYSTEM IN ALMOST EVERY DEFINITION IS CENTERED OVER
THE ARKLATEX EARLY THIS MORNING...WHICH WILL HAVE A TRACK RECORD
WHEN IT IS FINISHED LATE TONIGHT WITH AFFECTING ALMOST EVERY
CENTRAL CONUS STATE WITH SOME FORM OF IMPACTING WEATHER. A 70
DEGREE TEMPERATURE DIFFERENCE FROM NORTHWEST IOWA TO NORTHERN
MISSISSIPPI EARLY THIS MORNING HIGHLIGHTS THE BAROCLINICITY THAT
THE WARM AND MOIST ADVECTION IS OVERRIDING INTO OUR AREA.
PRECIPITATION WITH THE LEADING EDGE OF THIS IN THE SOUTHERN CWA
HAS BEEN A LIGHT MIXED BAG THUS FAR. NEAR DAYBREAK INTENSITY LOOKS
TO UPTICK IN RESPONSE TO INCREASING DIFFLUENCE AND LOWER TO MID-
LEVEL F-GEN. THIS WILL CAUSE A PRONOUNCED WET-BULBING COOLING
EFFECT AS INHERENT DRY AIR BECOMES SATURATED WITHIN THE LOW-LEVEL
NORTHEAST FLOW. EARLY MORNING AMDAR DATA NEAR CHICAGO INDICATE A
WARM NOSE AROUND 2C ALOFT AND A LOW-LEVEL COLD NOSE AROUND -5C...
BOTH OF WHICH THE RAP SEEMS TO BE INITIALIZING WELL WITH OVER ITS
PAST FEW RUNS...LENDING SOME CONFIDENCE OF FINE TUNING THE
FORECAST TOWARD IT THIS MORNING. THE VERTICAL PROFILES AND
EXPECTED UPTICK IN PRECIP INTENSITY SHOULD CAUSE THE MAIN TYPE AT
FIRST TO BE ICE PELLETS OR EVEN SOME LIGHT SNOW /WHICH HAS BEEN
REPORTED/. BEING WITHIN THE LOW-LEVEL CONVEYOR BELT OF THIS MATURE
SYSTEM THIS MORNING...WITH 45 KT NORTHEAST 925MB FLOW PER
PROFILERS...THIS SEEMS TO SUPPORT THE TREND FOR P-TYPE TO WANT TO
REMAIN AS SLEET WITH OCCASIONAL SNOW IN FAR NORTHERN PARTS OF THE
CWA INTO LATE MORNING WITH MINOR ACCUMULATIONS. MORE IMPORTANTLY
FOR IMPACTS IT ALSO KEEPS THE FREEZING RAIN CORRIDOR IN PLACE TO
THE SOUTH OF THIS...THROUGH THE MORNING AND EVEN POTENTIALLY EARLY
AFTERNOON. TO HELP VISUALIZE...THIS IS ROUGHLY 30 MILES OR SO
NORTH OR SOUTH OF INTERSTATE 80.
THE AREAS IN THE SHADOW OF THE LAKE...INCLUDING CENTRAL AREAS OF
THE CHICAGO METRO...STILL LOOK LIKE THEY COULD STRUGGLE TO SEE
TEMPERATURES DROP MUCH DUE TO THE STRONG ADVECTION FROM THE
LAKE...SO ICING IS A LITTLE LESS OF A THREAT FOR THESE IMMEDIATE
NEARSHORE LOCATIONS...INCLUDING DOWNTOWN. HOWEVER WIND SPEEDS WILL
BE THE MAXIMUM...GUSTING TO IMPRESSIVE MAGNITUDES TO 50 TO 60 MPH
THIS AFTERNOON AND EARLY EVENING.
THE INGREDIENTS FOR THE WINDS TODAY AND INTO EARLY EVENING CONTINUE
TO JUST BE TRULY STRIKING. PRESSURE FALLS OF AROUND 15MB ARE
FORECAST BETWEEN 10AM AND 3PM OVER MUCH OF THE CWA THIS AFTERNOON.
HAVE CONTINUED WITH FORECAST HIGH END WIND GUSTS AND CORRELATED
DUAL IMPACT WITH ANY ICED LINES AND LIMBS. WIDESPREAD POWER
OUTAGES STILL LOOK POTENTIALLY REALIZED WHERE THE HEAVIER ICE
ACCUMULATIONS OCCUR.
AS THE STACKED SYSTEM CENTER AND ASSOCIATED DEEP TROPOSPHERIC FOLD
MOVES TOWARD THE AREA MID-AFTERNOON...THE WARM MOIST CONVEYOR
BELT NOSE PUSHES INTO THE AREA WITH SOME HEAVY PRECIPITATION AGAIN
LIKELY. ELEVATED INSTABILITY VALUES SUPPORT THUNDER INCLUSION. THE
LOW WILL PASS OVER WITH WINDS THEN EASING. FORCING LOOKS ENOUGH
STILL TO WARRANT SCATTERED RAIN SHOWERS ACROSS THE AREA AND
POSSIBLY EVEN SOME DRIZZLE. THE CHANCE FOR SOME OF THIS TO BE SNOW
SHOWERS INCREASES OVERNIGHT...ALTHOUGH THE INTENSITY SHOULD BE
LIGHT ENOUGH WITH MARGINAL SURFACE TEMPERATURES TO NOT REALLY HAVE
ANY ACCUMULATION. SOME OF THESE SHOWERS MAY LINGER INTO TUESDAY
MORNING...WITH WRAPAROUND COLD ADVECTION KEEPING TEMPERATURES
FROM RISING ANY AND HIGHS IN THE 30S.
MTF
&&
.LONG TERM...
204 AM CST
WEDNESDAY THROUGH SUNDAY...
THE MAIN FEATURE OF THE EXTENDED FORECAST PERIOD IS THE
ESTABLISHMENT OF AN EASTERN NORTH AMERICAN MEAN TROUGH...WITH
UPPER RIDGING BUILDING ACROSS THE NORTHWESTERN U.S. AND WESTERN
CANADA. THIS SETS THE STAGE FOR A PERIOD OF BELOW-AVERAGE COLD
THURSDAY THROUGH SUNDAY...THE FIRST MULTIPLE DAY STRETCH OF
BELOW AVERAGE TEMPERATURES FOR OUR AREA SINCE THE WEEK BEFORE
THANKSGIVING.
BY WEDNESDAY MORNING...THE OCCLUDED SURFACE LOW PRESSURE
ASSOCIATED WITH OUR NEAR TERM WINTER STORM WILL BE FILLING OVER
THE NORTHERN GREAT LAKES...WITH ITS TRAILING COLD FRONT EAST OF
THE FORECAST AREA. ANOTHER MID-LEVEL SHORT WAVE IS PROGGED TO
LIFT OUT OF THE LARGE WESTERN CONUS UPPER TROUGH DURING THE
MORNING...AND EVENTUALLY TAKING THE OLD SURFACE LOW OFF TO THE
NORTHEAST OF THE REGION. 00Z GFS/ECMWF AND GEM RUNS ARE ALL VERY
SIMILAR IN GENERATING AN AXIS OF LIGHT QPF BETWEEN 0.01-0.07"
ACROSS PARTS OF NORTH CENTRAL AND NORTHEAST ILLINOIS DURING THE
MORNING...MAINLY NORTHWEST OF THE I-55 CORRIDOR. USING A MODEL
BLEND QPF AND COBB OUTPUT SNOW/LIQUID RATIOS FROM ROUGHLY 11-13:1
ACROSS THE MAIN QPF AXIS DURING THE PERIOD...SUPPORTING A FEW
TENTHS OF AN INCH OF SNOW ACCUMULATION PERHAPS UP TO A HALF
INCH NORTHWEST OF THE CHICAGO AREA IN THE 12-18Z PERIOD. ONLY A
FEW FLURRIES PERHAPS LINGERING AT MIDDAY/EARLY AFTERNOON.
THE LONG WAVE UPPER TROUGH EVOLVES EASTWARD ACROSS CENTRAL NORTH
AMERICA WEDNESDAY NIGHT AND THURSDAY...EVENTUALLY BECOMING
ELONGATED IN A POSITIVE-TILT SOUTHWEST-NORTHEAST ORIENTATION BY
FRIDAY WITH THE TROUGH AXIS MOVING SOUTHEAST OF THE FORECAST
AREA. AT THE SURFACE...SURFACE LOW PRESSURE ASSOCIATED WITH
WEDNESDAYS DISTURBANCE PULLS AWAY TO THE EAST...WITH A BROAD
REGION OF COLDER WEST-NORTHEAST LOW LEVEL FLOW EAST OF STRONG
SURFACE HIGH PRESSURE DEVELOPING ACROSS THE NORTHERN AND
CENTRAL HIGH PLAINS. WHILE A FEW MINOR AMPLITUDE DISTURBANCES
APPEAR TO MOVE THROUGH THE FLOW ALOFT...LOW LEVELS ARE DOMINATED
BY COLDER...DRIER MODIFIED ARCTIC AIR AND LITTLE IN THE WAY OF
ORGANIZED PRECIP CHANCES ARE NOTED THROUGH THE WEEKEND. COLD
AIR...APPROACHING -10 TO -12 C AT 850 MB BY EARLY FRIDAY...
WILL LIKELY SUPPORT LAKE EFFECT SNOW SHOWERS DOWNWIND OF THE
LAKE ACROSS LOWER MICHIGAN. AS INDICATED ABOVE...THE PERIOD
FROM THURSDAY THROUGH SATURDAY LOOKS TO BE OUR FIRST MULTI-DAY
STRETCH OF BELOW AVERAGE TEMPS IN OVER A MONTH. MODEL LOW LEVEL
THERMAL PROGS AND GFS/ECMWF MOS NUMBERS DEPICT HIGHS IN THE 20S
THUR-FRI WITH LOWS IN THE TEENS AND EVEN A FEW SINGLE DIGITS
IN OUR TYPICALLY COLDEST SPOTS. AVERAGE TEMPS AROUND THE FIRST
OF THE YEAR ARE 30/14 AT ROCKFORD AND 31/17 FOR CHICAGO.
RATZER
&&
.HYDROLOGY...
A POWERFUL STORM SYSTEM WILL DRAW COPIOUS AMOUNTS OF MOISTURE
NORTHWARD ON MONDAY. SOME OF THE PRECIPITATION WILL FALL AS SLEET
AND FREEZING RAIN. TOTAL FORECAST LIQUID EQUIVALENT AMOUNTS ARE IN
THE 1 TO 1.5 INCH RANGE ACROSS NORTHERN AND CENTRAL ILLINOIS AND
NORTHWEST INDIANA. WITH SUCH ANOMALOUSLY HIGH MOISTURE
LEVELS...LOCALLY HIGHER TOTALS ARE PROBABLE. 24-HOUR RAIN AMOUNTS
FROM SATURDAY INTO SUNDAY MORNING WERE UP TO 2-3 INCHES SOUTH OF
THE KANKAKEE RIVER. THIS RAIN HAS ALREADY RESULTED IN RISES ON
RIVERS AND STREAMS IN THIS AREA. THE ADDITIONAL RAIN ON MONDAY
WILL EXACERBATE AND PROLONG ONGOING RISES. FOR AREAS FARTHER
NORTH...RIVER AND STREAM LEVELS ARE ALREADY RUNNING ABOVE
NORMAL...AND THE HEAVY FORECAST PRECIPITATION WILL RESULT IN
RENEWED RISES.
RC
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* MVFR CIGS CONTINUE THROUGH MID-LATE MORNING LOWERING TO IFR BY
LATE MORNING AND INTO LIFR THIS AFTERNOON.
* IFR VSBYS IN PRECIPITATION LATER THIS MORNING.
* NNE-NE WINDS WITH GUSTS 25-28 KT...VEERING E THIS MORNING WITH
GUSTS 30-35 KT...35-40 KT IN THE AFTERNOON.
* WINTRY MIX OF PCPN. FZRA HAS BEGUN SLIGHTLY EARLIER WITH VSBYS
INTERMITTENTLY DROPPING IN HEAVIER POCKETS. PCPN SHOULD
TRANSITION TO ALL LIQUID BY EARLY TO MID AFTERNOON.
* ISOLATED TSRA LATER THIS AFTERNOON.
KMD/MM
//DISCUSSION...UPDATED 12Z...
CONCERNS INITIALLY AROUND PRECIPITATION TYPE THIS MORNING. A MIXED
BAG IS BEING REPORTED AROUND THE AREA...WITH LIQUID PRECIPITATION
THE MAIN PRECIPITATION TYPE ALONG THE FAR SOUTHERN AREAS SOUTH OF
I-80 WHERE SURFACE TEMPERATURES ARE HOVERING RIGHT AROUND
FREEZING. ALONG THE I-80 TO I-90 CORRIDOR CLOSER TO CHICAGO P-TYPE
IS MAINLY SLEET...THEN A NOW SLEET MIX FARTHER NORTH AND WEST
TOWARD ROCKFORD AND WISCONSIN. EXPECT THAT AS THE WARM LAYER ALOFT
SPREADS NORTH THAT SLEET WILL TRANSITION TO FZRA/RA. MARGINAL
SURFACE TEMPERATURES SHOULD PRECLUDE A SIGNIFICANT ICE THREAT
CLOSER TO CHICAGO BUT ACCUMS REMAIN POSSIBLE...ESPECIALLY AS RATES
INCREASE AND SOME ADDITIONAL LOW LEVEL COOLING OCCURS. SLEET
ACCUMULATIONS HAVE OCCURRED AND WILL CONTINUE AT LEAST FOR A FEW
MORE HOURS. -SN/PL HANG ON LONGEST NORTHWEST...THEN A TRANSITION
TO RA THIS AFTERNOON. EVEN A TS CHANCE IN THE MID TO LATE
AFTERNOON.
OTHER CONCERN IS THE STRONG WINDS THAT WILL RAMP UP THIS MORNING
AND EVEN MORE SO THIS AFTERNOON. EXPECT GUSTS IN THE 30 KT RANGE
THEN TRANSITIONING TO POSSIBLY 40 KT THIS AFTERNOON...ESPECIALLY
CLOSER TO THE LAKE. CIGS WILL CONTINUE TO LOWER TO LOWER END
MVFR...THEN IFR AND EVEN LIFR LATER TODAY. VSBYS SHOULD LARGELY
HOLD MVFR FOR SOME TIME EXCEPT WEST IN THE HEAVIER PRECIPITATION
THAT IS SNOW AND AS PRECIP RATES INTENSIFY MID TO LATE MORNING.
WINDS SLACKEN TONIGHT AND TURN SOUTHWEST WITH PRECIP RATES
DECREASING...THOUGH THERE SHOULD BE A TRANSITIONING TO RA/SN MIX
OVERNIGHT.
KMD
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* MEDIUM TO HIGH CONFIDENCE IN GENERAL CIG TRENDS THOUGH MEDIUM ON
TRANSITION TIMES.
* HIGH IN OCCURRENCE OF IFR VSBYS AT TIMES BUT LOW ON THE LENGTH
OF TIME FOR LESS THAN 1SM VSBY.
* HIGH CONFIDENCE IN WIND TRENDS.
* HIGH CONFIDENCE IN MIXED/FREEZING PRECIP. MEDIUM HIGH CONFIDENCE
IN TIMING OF PCPN TYPE CHANGES.
* MEDIUM CONFIDENCE IN ISOLATED TS THIS AFTERNOON...BUT LOW
CONFIDENCE IN OCCURRENCE AT THE TERMINALS.
KMD/MM
//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...
TUESDAY NIGHT...VFR. SW WINDS.
WEDNESDAY...MVFR CIGS. CHANCE -SN OR -RASN EARLY WITH IFR
POSSIBLE. VFR/WX NIL LATE. SW WINDS.
THURSDAY...MVFR CIGS PSBL IN THE MORNING. W WINDS.
FRIDAY/SATURDAY...VFR/WX NIL. W WINDS.
SUNDAY...LAKE EFFECT SNOW SHOWERS PSBL MAINLY ALONG AND EAST OF
THE TERMINALS WITH MVFR CIGS. OTHERWISE VFR WITH NW WINDS.
KMD
&&
.MARINE...
416 AM CST
A STRONG PRESSURE GRADIENT BETWEEN ARCTIC HIGH PRESSURE IN
SOUTHERN ONTARIO AND DEEP LOW PRESSURE OVER THE ARKLATEX REGION
WILL STRENGTHEN TODAY AS THE LOW SHIFTS NORTHWARD THROUGH THE DAY
AND THE HIGH SHIFTS EASTWARD. GALE FORCE WINDS WILL INCREASE OVER
THE ENTIRE LAKE TODAY...WITH STORM FORCE WINDS EXPECTED FOR A
TIME THIS AFTERNOON AND EARLY EVENING ACROSS THE SOUTHERN HALF OF
THE LAKE.WITH A STRONG EAST FETCH...THESE WINDS LOOK TO AFFECT THE
ILLINOIS NEARSHORE AS WELL. THESE STRONG WINDS WILL RESULT IN
WAVES POSSIBLY REACHING NEAR 20 FT OVER THE SOUTH HALF OF THE
LAKE AND ILLINOIS NEARSHORE. THERE MAY BE A BRIEF PERIOD OF STORM
FORCE GUSTS THIS EVENING ACROSS THE NORTH...BUT HAVE HELD TO THE
GALE WARNING FOR THE NORTH HALF AS THE WINDOW APPEARS TO BE
SHORTER THAN FOR THE SOUTH HALF. THE LOW WILL PUSH NORTHEAST OVER
THE LAKE OVERNIGHT THEN NORTHEAST OF THE LAKE ON TUESDAY...AND
THIS WILL ALLOW WINDS AND WAVES TO SUBSIDE SIGNIFICANTLY AFTER
THIS POINT. MODERATE WESTERLY FLOW WILL CONTINUE OVER THE LAKE
FOR MUCH OF THE LATTER HALF OF THE WEEK.
KMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WINTER STORM WARNING...ILZ013-ILZ014-ILZ021-ILZ022 UNTIL 3 PM
MONDAY.
LAKESHORE FLOOD WARNING...ILZ006-ILZ014 UNTIL MIDNIGHT TUESDAY.
HIGH WIND WARNING...ILZ006-ILZ014...1 PM MONDAY TO 7 PM MONDAY.
WINTER STORM WARNING...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ019-ILZ020 UNTIL 6 PM MONDAY.
WIND ADVISORY...ILZ013-ILZ021-ILZ022-ILZ023-ILZ032-ILZ033-ILZ039
UNTIL 6 PM MONDAY.
FLASH FLOOD WATCH...ILZ033-ILZ039 UNTIL 6 PM MONDAY.
FREEZING RAIN ADVISORY...ILZ033-ILZ039 UNTIL NOON MONDAY.
FREEZING RAIN ADVISORY...ILZ023-ILZ032 UNTIL 3 PM MONDAY.
IN...FREEZING RAIN ADVISORY...INZ001-INZ002 UNTIL 3 PM MONDAY.
WIND ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL 6 PM
MONDAY.
FLASH FLOOD WATCH...INZ010-INZ011-INZ019 UNTIL 6 PM MONDAY.
FREEZING RAIN ADVISORY...INZ010-INZ011-INZ019 UNTIL NOON MONDAY.
LM...STORM WARNING...ILLINOIS NEARSHORE WATERS UNTIL 9 PM MONDAY.
GALE WARNING...INDIANA NEARSHORE WATERS UNTIL 9 PM MONDAY.
STORM WARNING...LMZ777-LMZ779 UNTIL MIDNIGHT TUESDAY.
&&
$$
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AREA FORECAST DISCUSSION
National Weather Service Lincoln IL
603 AM CST MON DEC 28 2015
.SHORT TERM...(Today)
ISSUED AT 343 AM CST MON DEC 28 2015
Rain has overspread the entire forecast area early this morning.
Galesburg temperature has dropped to 32, so some freezing rain
occurring there. Sleet may be mixing with rain north of a line from
Canton to Bloomington, but no confirmation is apparent in the web-
cameras that are available. Bloomington`s observation has carried
`unknown precipitation` for several hours already this morning with
air temps down to 33, so some sleet possibly occurring there.
The 00z NAM came in with warmer surface temps than previous model
runs, but the RAP and GFS keep a colder airmass across our northern
counties through the morning, supporting the winter weather scenario
in our headline products. Even the NAM still supports some freezing
rain with a mix of sleet this morning north of Peoria. We may see
slightly less ice than a quarter inch across the winter storm
warning area, but the impacts from any amount of ice could be large
due to the strong winds blowing the trees and power lines around
with any amount of ice. We will be keeping the headlines going
without any changes this morning. Winter storm warning for freezing
rain and sleet from Peoria and north until 3 pm looks fine, with a
freezing rain advisory from Fulton to McLean counties until noon
looking ok too.
The track of the surface low from south to north up the Mississippi
River Valley supports some thunder potential in our eastern and
southern counties through the day, with locally heavy rain still
possible. It also supports a surge of warm air into our entire
forecast area this afternoon, helping to shut down any additional
wintry precipitation. Impacts from any ice accumulation could last
after surface temperatures climb above freezing, due to strong winds
affecting icy trees and power lines.
A dry slot is forecast to progress from south to north through
Illinois this afternoon, so we diminished precip chances
accordingly. Areas north of I-74 should see precip linger until
evening.
.LONG TERM...(Tonight through Sunday)
ISSUED AT 343 AM CST MON DEC 28 2015
Strong surface low pressure of 997 mb over southeast OK to lift ne
into west central IL early this evening and lift across nw IL during
this evening. Low pressure will then weaken to 1002 mb as it lifts
into west central lower MI by 12Z/6 am Tue. Rain will diminish
quickly from sw to ne during this evening, with highest pops north
of I-74 early this evening, and just 20-30% chances of light
precipitation lingering overnight from I-74 northeast. Enough cold
air present to give a chance of light snow too over the IL river
valley tonight but little or no accumulations expected nw of the IL
river. Winds will drop off below wind advisory criteria by 6 pm and
become sw 15-25 mph by overnight. Went a few degrees cooler for lows
tonight ranging from near 30F far western CWA to the mid to upper
30s from I-57 east, with mildest readings near the Wabash river.
Breezy sw winds and clouds continue to linger over central IL on Tue
in wake of strong storm system pulling ne across Lake Huron, but
should be dry. Temperatures not expected to climb but a few degrees
on Tue with highs in the low to mid 30s west of I-57 and upper
30s/lower 40s east of I-57. Dry conditions continue on Tue night as
sw winds diminish. An approaching short wave from the Pacific states
to keep clouds around, with light snow chances just west of IL
overnight Tue night. Lows Tue night range from mid 20s over IL river
valley to lower 30s from I-70 southeast.
A large short wave lifts ne across IL and into lower MI during Wed
but has limited moisture over IL so will continue small chances (20-
30%) of light precipitation, mainly light snow central IL and chance
of light rain/snow in eastern/se IL. A fair amount of clouds again
on Wed with highs ranging from lower 30s over IL river valley to
around 40F in southeast IL.
Extended forecast models continue to show a large upper level trof
dominating the northeast half of the country during the 2nd half of
the week. Also large Canadian high pressure over the Rockies and
ridging into the southern plains to keep a cooler nw flow over IL
from Thu into New Years weekend. Temperatures averaging a bit below
normal for a change especially Thu/Fri when highs as cold as mid to
upper 20s in central IL and lows in the teens. Brunt of light snow
chances stays ne of central IL over the Great Lakes region late this
work week but could see more clouds linger still on Thu especially
in ne CWA, before mostly sunny skies eventually arrives Fri into the
weekend.
&&
.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
ISSUED AT 600 AM CST MON DEC 28 2015
Steady rains will continue today at all terminal sites. Freezing
rain will be mainly focused north of a line from Peoria to
Bloomington this morning, before temperatures rise well above
freezing this afternoon. Light glazing will be mainly above the
ground at the terminal sites of PIA and BMI, but spotty slippery
conditions could develop on bridges and overpasses this morning.
MVFR clouds are expected to dip to IFR by 14-15z, and remain IFR
for a majority of the day. BMI has already dropped to IFR cloud
levels and should remain there until later evening.
Rain chances will diminish from south to north starting after 3
pm/21z, as a dry slot wraps into Illinois.
The other major impact from this storm will be with the strong
and gusty easterly winds this morning as the storm approaches. We
expect easterly winds of 25 to 35 kts with gusts to 45 kts this
morning, as the most intense precip moves over the area. Winds
should become southeast to south later this afternoon as the
storm system shifts to our north with speeds gradually to
decreasing to between 15 and 25 kts by 03z. Wind direction will
eventually become westerly after 03z.
&&
.ILX Watches/Warnings/Advisories...
Flash Flood Watch through this afternoon for ILZ044>046-049-050-
052>057-061>063-066>068-071>073.
Wind Advisory until 6 PM CST this evening for ILZ027>031-036>038-
040>057-061.
Winter Storm Warning until 3 PM CST this afternoon for
ILZ027>031.
Flash Flood Watch through this evening for ILZ051.
Freezing Rain Advisory until noon CST today for ILZ036>038.
&&
$$
SHORT TERM...Shimon
LONG TERM...07
AVIATION...Shimon
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
602 AM CST MON DEC 28 2015
.SHORT TERM...
401 AM CST
THROUGH TUESDAY...
A MAJOR WIND AND ICE EVENT FOR A GOOD PORTION OF THE AREA...ALONG
WITH SOME OTHER ACCOMPANYING IMPACTS...IS BEGINNING TO UNFOLD INTO
THE REGION EARLY THIS MORNING. NO CHANGES PLANNED TO THE SPATIAL
EXTENT OF THE CURRENT MYRIAD OF HEADLINES...AS THEY COVER THIS
DYNAMIC SYSTEM WELL...WITH JUST SOME MINOR SHIFTS TO TIMING TO
COVER PRIME THREAT TIMES. WE ARE AT THE STAGE NOW OF INCORPORATING
OBSERVATIONAL TRENDS INTO THE GOING FORECAST WITH HOPEFULLY
ADJUSTMENTS MORE SO THAN MAJOR SHIFTS...AND THUS FAR THAT IS THE
CASE. HOWEVER BEING IN A TRANSITIONAL PRECIPITATION EVENT WHERE
SPECIFIC SURFACE AND ALOFT TEMPERATURES PLAY CRITICAL ROLES MAKES
THIS PARTICULARLY CHALLENGING.
THE MOST NOTEWORTHY CHANGES/OBSERVATIONS IN SUMMARY ARE THE OVERALL
FORECAST PRECIPITATION AMOUNTS HAVE BEEN INCREASED AREAWIDE LATE
MORNING THROUGH THE AFTERNOON AS IT IS MORE APPARENT CONVECTIVE
ELEMENTS AND SLANTWISE INSTABILITY WILL IMPINGE INTO THE AREA. THE
OVERLAP AREA OF THESE HEAVIER INTENSITY/AMOUNTS AND THE STILL COLD
ENOUGH FOR FREEZING RAIN APPEARS TO BE ALONG/NORTH OF INTERSTATE
80 AND ALONG AND WEST OF ILLINOIS 47...SO HAVE BUMPED UP FORECAST
ICE ACCUMULATIONS IN THESE AREAS AND PLACED HEAVY WORDING IN THE
FORECAST. HAVE ALSO ADDED ISOLATED/SCATTERED THUNDER...ALTHOUGH
THAT SHOULD BE MAINLY AFTER THE PEAK ICING TIME.
ALSO CONTINUED AN ADJUSTMENT OF A BIT SLOWER TEMPERATURE RECOVERY
IN THE IMMEDIATE LOW-LEVELS RESULTING IN LONGER SLEET DURATION
ALONG AND NORTH OF I-88...WITH THAT POTENTIALLY THE DOMINANT
PRECIPITATION TYPE MOST OF THE MORNING IN THAT REGION. HAVE UPPED
SLEET ACCUMULATION TO AROUND AN INCH THOUGH HIGHER TOTALS
CERTAINLY POSSIBLE DEPENDING ON RATE. WHILE IMPACTS DURING THE
MORNING MAY BE LESS IF THIS MAINLY SLEET/INTERMITTENT SNOW
MATERIALIZES...THE ICING POTENTIAL IN THE AFTERNOON WITH STRONG
WINDS STILL LOOKS ON TRACK.
A VERY POTENT SYSTEM IN ALMOST EVERY DEFINITION IS CENTERED OVER
THE ARKLATEX EARLY THIS MORNING...WHICH WILL HAVE A TRACK RECORD
WHEN IT IS FINISHED LATE TONIGHT WITH AFFECTING ALMOST EVERY
CENTRAL CONUS STATE WITH SOME FORM OF IMPACTING WEATHER. A 70
DEGREE TEMPERATURE DIFFERENCE FROM NORTHWEST IOWA TO NORTHERN
MISSISSIPPI EARLY THIS MORNING HIGHLIGHTS THE BAROCLINICITY THAT
THE WARM AND MOIST ADVECTION IS OVERRIDING INTO OUR AREA.
PRECIPITATION WITH THE LEADING EDGE OF THIS IN THE SOUTHERN CWA
HAS BEEN A LIGHT MIXED BAG THUS FAR. NEAR DAYBREAK INTENSITY LOOKS
TO UPTICK IN RESPONSE TO INCREASING DIFFLUENCE AND LOWER TO MID-
LEVEL F-GEN. THIS WILL CAUSE A PRONOUNCED WET-BULBING COOLING
EFFECT AS INHERENT DRY AIR BECOMES SATURATED WITHIN THE LOW-LEVEL
NORTHEAST FLOW. EARLY MORNING AMDAR DATA NEAR CHICAGO INDICATE A
WARM NOSE AROUND 2C ALOFT AND A LOW-LEVEL COLD NOSE AROUND -5C...
BOTH OF WHICH THE RAP SEEMS TO BE INITIALIZING WELL WITH OVER ITS
PAST FEW RUNS...LENDING SOME CONFIDENCE OF FINE TUNING THE
FORECAST TOWARD IT THIS MORNING. THE VERTICAL PROFILES AND
EXPECTED UPTICK IN PRECIP INTENSITY SHOULD CAUSE THE MAIN TYPE AT
FIRST TO BE ICE PELLETS OR EVEN SOME LIGHT SNOW /WHICH HAS BEEN
REPORTED/. BEING WITHIN THE LOW-LEVEL CONVEYOR BELT OF THIS MATURE
SYSTEM THIS MORNING...WITH 45 KT NORTHEAST 925MB FLOW PER
PROFILERS...THIS SEEMS TO SUPPORT THE TREND FOR P-TYPE TO WANT TO
REMAIN AS SLEET WITH OCCASIONAL SNOW IN FAR NORTHERN PARTS OF THE
CWA INTO LATE MORNING WITH MINOR ACCUMULATIONS. MORE IMPORTANTLY
FOR IMPACTS IT ALSO KEEPS THE FREEZING RAIN CORRIDOR IN PLACE TO
THE SOUTH OF THIS...THROUGH THE MORNING AND EVEN POTENTIALLY EARLY
AFTERNOON. TO HELP VISUALIZE...THIS IS ROUGHLY 30 MILES OR SO
NORTH OR SOUTH OF INTERSTATE 80.
THE AREAS IN THE SHADOW OF THE LAKE...INCLUDING CENTRAL AREAS OF
THE CHICAGO METRO...STILL LOOK LIKE THEY COULD STRUGGLE TO SEE
TEMPERATURES DROP MUCH DUE TO THE STRONG ADVECTION FROM THE
LAKE...SO ICING IS A LITTLE LESS OF A THREAT FOR THESE IMMEDIATE
NEARSHORE LOCATIONS...INCLUDING DOWNTOWN. HOWEVER WIND SPEEDS WILL
BE THE MAXIMUM...GUSTING TO IMPRESSIVE MAGNITUDES TO 50 TO 60 MPH
THIS AFTERNOON AND EARLY EVENING.
THE INGREDIENTS FOR THE WINDS TODAY AND INTO EARLY EVENING CONTINUE
TO JUST BE TRULY STRIKING. PRESSURE FALLS OF AROUND 15MB ARE
FORECAST BETWEEN 10AM AND 3PM OVER MUCH OF THE CWA THIS AFTERNOON.
HAVE CONTINUED WITH FORECAST HIGH END WIND GUSTS AND CORRELATED
DUAL IMPACT WITH ANY ICED LINES AND LIMBS. WIDESPREAD POWER
OUTAGES STILL LOOK POTENTIALLY REALIZED WHERE THE HEAVIER ICE
ACCUMULATIONS OCCUR.
AS THE STACKED SYSTEM CENTER AND ASSOCIATED DEEP TROPOSPHERIC FOLD
MOVES TOWARD THE AREA MID-AFTERNOON...THE WARM MOIST CONVEYOR
BELT NOSE PUSHES INTO THE AREA WITH SOME HEAVY PRECIPITATION AGAIN
LIKELY. ELEVATED INSTABILITY VALUES SUPPORT THUNDER INCLUSION. THE
LOW WILL PASS OVER WITH WINDS THEN EASING. FORCING LOOKS ENOUGH
STILL TO WARRANT SCATTERED RAIN SHOWERS ACROSS THE AREA AND
POSSIBLY EVEN SOME DRIZZLE. THE CHANCE FOR SOME OF THIS TO BE SNOW
SHOWERS INCREASES OVERNIGHT...ALTHOUGH THE INTENSITY SHOULD BE
LIGHT ENOUGH WITH MARGINAL SURFACE TEMPERATURES TO NOT REALLY HAVE
ANY ACCUMULATION. SOME OF THESE SHOWERS MAY LINGER INTO TUESDAY
MORNING...WITH WRAPAROUND COLD ADVECTION KEEPING TEMPERATURES
FROM RISING ANY AND HIGHS IN THE 30S.
MTF
&&
.LONG TERM...
204 AM CST
WEDNESDAY THROUGH SUNDAY...
THE MAIN FEATURE OF THE EXTENDED FORECAST PERIOD IS THE
ESTABLISHMENT OF AN EASTERN NORTH AMERICAN MEAN TROUGH...WITH
UPPER RIDGING BUILDING ACROSS THE NORTHWESTERN U.S. AND WESTERN
CANADA. THIS SETS THE STAGE FOR A PERIOD OF BELOW-AVERAGE COLD
THURSDAY THROUGH SUNDAY...THE FIRST MULTIPLE DAY STRETCH OF
BELOW AVERAGE TEMPERATURES FOR OUR AREA SINCE THE WEEK BEFORE
THANKSGIVING.
BY WEDNESDAY MORNING...THE OCCLUDED SURFACE LOW PRESSURE
ASSOCIATED WITH OUR NEAR TERM WINTER STORM WILL BE FILLING OVER
THE NORTHERN GREAT LAKES...WITH ITS TRAILING COLD FRONT EAST OF
THE FORECAST AREA. ANOTHER MID-LEVEL SHORT WAVE IS PROGGED TO
LIFT OUT OF THE LARGE WESTERN CONUS UPPER TROUGH DURING THE
MORNING...AND EVENTUALLY TAKING THE OLD SURFACE LOW OFF TO THE
NORTHEAST OF THE REGION. 00Z GFS/ECMWF AND GEM RUNS ARE ALL VERY
SIMILAR IN GENERATING AN AXIS OF LIGHT QPF BETWEEN 0.01-0.07"
ACROSS PARTS OF NORTH CENTRAL AND NORTHEAST ILLINOIS DURING THE
MORNING...MAINLY NORTHWEST OF THE I-55 CORRIDOR. USING A MODEL
BLEND QPF AND COBB OUTPUT SNOW/LIQUID RATIOS FROM ROUGHLY 11-13:1
ACROSS THE MAIN QPF AXIS DURING THE PERIOD...SUPPORTING A FEW
TENTHS OF AN INCH OF SNOW ACCUMULATION PERHAPS UP TO A HALF
INCH NORTHWEST OF THE CHICAGO AREA IN THE 12-18Z PERIOD. ONLY A
FEW FLURRIES PERHAPS LINGERING AT MIDDAY/EARLY AFTERNOON.
THE LONG WAVE UPPER TROUGH EVOLVES EASTWARD ACROSS CENTRAL NORTH
AMERICA WEDNESDAY NIGHT AND THURSDAY...EVENTUALLY BECOMING
ELONGATED IN A POSITIVE-TILT SOUTHWEST-NORTHEAST ORIENTATION BY
FRIDAY WITH THE TROUGH AXIS MOVING SOUTHEAST OF THE FORECAST
AREA. AT THE SURFACE...SURFACE LOW PRESSURE ASSOCIATED WITH
WEDNESDAYS DISTURBANCE PULLS AWAY TO THE EAST...WITH A BROAD
REGION OF COLDER WEST-NORTHEAST LOW LEVEL FLOW EAST OF STRONG
SURFACE HIGH PRESSURE DEVELOPING ACROSS THE NORTHERN AND
CENTRAL HIGH PLAINS. WHILE A FEW MINOR AMPLITUDE DISTURBANCES
APPEAR TO MOVE THROUGH THE FLOW ALOFT...LOW LEVELS ARE DOMINATED
BY COLDER...DRIER MODIFIED ARCTIC AIR AND LITTLE IN THE WAY OF
ORGANIZED PRECIP CHANCES ARE NOTED THROUGH THE WEEKEND. COLD
AIR...APPROACHING -10 TO -12 C AT 850 MB BY EARLY FRIDAY...
WILL LIKELY SUPPORT LAKE EFFECT SNOW SHOWERS DOWNWIND OF THE
LAKE ACROSS LOWER MICHIGAN. AS INDICATED ABOVE...THE PERIOD
FROM THURSDAY THROUGH SATURDAY LOOKS TO BE OUR FIRST MULTI-DAY
STRETCH OF BELOW AVERAGE TEMPS IN OVER A MONTH. MODEL LOW LEVEL
THERMAL PROGS AND GFS/ECMWF MOS NUMBERS DEPICT HIGHS IN THE 20S
THUR-FRI WITH LOWS IN THE TEENS AND EVEN A FEW SINGLE DIGITS
IN OUR TYPICALLY COLDEST SPOTS. AVERAGE TEMPS AROUND THE FIRST
OF THE YEAR ARE 30/14 AT ROCKFORD AND 31/17 FOR CHICAGO.
RATZER
&&
.HYDROLOGY...
A POWERFUL STORM SYSTEM WILL DRAW COPIOUS AMOUNTS OF MOISTURE
NORTHWARD ON MONDAY. SOME OF THE PRECIPITATION WILL FALL AS SLEET
AND FREEZING RAIN. TOTAL FORECAST LIQUID EQUIVALENT AMOUNTS ARE IN
THE 1 TO 1.5 INCH RANGE ACROSS NORTHERN AND CENTRAL ILLINOIS AND
NORTHWEST INDIANA. WITH SUCH ANOMALOUSLY HIGH MOISTURE
LEVELS...LOCALLY HIGHER TOTALS ARE PROBABLE. 24-HOUR RAIN AMOUNTS
FROM SATURDAY INTO SUNDAY MORNING WERE UP TO 2-3 INCHES SOUTH OF
THE KANKAKEE RIVER. THIS RAIN HAS ALREADY RESULTED IN RISES ON
RIVERS AND STREAMS IN THIS AREA. THE ADDITIONAL RAIN ON MONDAY
WILL EXACERBATE AND PROLONG ONGOING RISES. FOR AREAS FARTHER
NORTH...RIVER AND STREAM LEVELS ARE ALREADY RUNNING ABOVE
NORMAL...AND THE HEAVY FORECAST PRECIPITATION WILL RESULT IN
RENEWED RISES.
RC
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 12Z...
* MVFR CIGS CONTINUE THROUGH MID-LATE MORNING LOWERING TO IFR BY
LATE MORNING AND INTO LIFR THIS AFTERNOON.
* IFR VSBYS IN PRECIPITATION LATER THIS MORNING.
* NNE-NE WINDS WITH GUSTS 25-28 KT...VEERING E THIS MORNING WITH
GUSTS 30-35 KT...35-40 KT IN THE AFTERNOON.
* WINTRY MIX OF PCPN...STARTING OUT AS A PERIOD OF PL AND THEN
BECMG FZRAPL/RAPL. PCPN WILL INTENSIFY BY LATE MORNING THROUGH
EARLY EVENING. PCPN SHOULD TRANSITION TO ALL LIQUID BY EARLY TO
MID AFTERNOON.
* ISOLATED TSRA LATER THIS AFTERNOON.
KMD
//DISCUSSION...UPDATED 12Z...
CONCERNS INITIALLY AROUND PRECIPITATION TYPE THIS MORNING. A MIXED
BAG IS BEING REPORTED AROUND THE AREA...WITH LIQUID PRECIPITATION
THE MAIN PRECIPITATION TYPE ALONG THE FAR SOUTHERN AREAS SOUTH OF
I-80 WHERE SURFACE TEMPERATURES ARE HOVERING RIGHT AROUND
FREEZING. ALONG THE I-80 TO I-90 CORRIDOR CLOSER TO CHICAGO P-TYPE
IS MAINLY SLEET...THEN A NOW SLEET MIX FARTHER NORTH AND WEST
TOWARD ROCKFORD AND WISCONSIN. EXPECT THAT AS THE WARM LAYER ALOFT
SPREADS NORTH THAT SLEET WILL TRANSITION TO FZRA/RA. MARGINAL
SURFACE TEMPERATURES SHOULD PRECLUDE A SIGNIFICANT ICE THREAT
CLOSER TO CHICAGO BUT ACCUMS REMAIN POSSIBLE...ESPECIALLY AS RATES
INCREASE AND SOME ADDITIONAL LOW LEVEL COOLING OCCURS. SLEET
ACCUMULATIONS HAVE OCCURRED AND WILL CONTINUE AT LEAST FOR A FEW
MORE HOURS. -SN/PL HANG ON LONGEST NORTHWEST...THEN A TRANSITION
TO RA THIS AFTERNOON. EVEN A TS CHANCE IN THE MID TO LATE
AFTERNOON.
OTHER CONCERN IS THE STRONG WINDS THAT WILL RAMP UP THIS MORNING
AND EVEN MORE SO THIS AFTERNOON. EXPECT GUSTS IN THE 30 KT RANGE
THEN TRANSITIONING TO POSSIBLY 40 KT THIS AFTERNOON...ESPECIALLY
CLOSER TO THE LAKE. CIGS WILL CONTINUE TO LOWER TO LOWER END
MVFR...THEN IFR AND EVEN LIFR LATER TODAY. VSBYS SHOULD LARGELY
HOLD MVFR FOR SOME TIME EXCEPT WEST IN THE HEAVIER PRECIPITATION
THAT IS SNOW AND AS PRECIP RATES INTENSIFY MID TO LATE MORNING.
WINDS SLACKEN TONIGHT AND TURN SOUTHWEST WITH PRECIP RATES
DECREASING...THOUGH THERE SHOULD BE A TRANSITIONING TO RA/SN MIX
OVERNIGHT.
KMD
//ORD AND MDW CONFIDENCE...UPDATED 12Z...
* MEDIUM TO HIGH CONFIDENCE IN GENERAL CIG TRENDS THOUGH MEDIUM ON
TRANSITION TIMES.
* HIGH IN OCCURRENCE OF IFR VSBYS AT TIMES BUT LOW ON THE LENGTH
OF TIME FOR LESS THAN 1SM VSBY.
* HIGH CONFIDENCE IN WIND TRENDS.
* HIGH CONFIDENCE IN A PERIOD OF MIXED PRECIP MONDAY...MEDIUM
CONFIDENCE IN TIMING OF PCPN TYPE CHANGES. MEDIUM HIGH THAT
INITIAL MIXED P-TYPE WOULD BE SLEET AND THAT THE PERIOD OF FZRA
WILL BE SOMEWHAT LIMITED...ESPECIALLY AT MDW.
* MEDIUM CONFIDENCE IN ISOLATED TS THIS AFTERNOON...BUT LOW
CONFIDENCE IN OCCURRENCE AT THE TERMINALS.
KMD
//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...
TUESDAY NIGHT...VFR. SW WINDS.
WEDNESDAY...MVFR CIGS. CHANCE -SN OR -RASN EARLY WITH IFR
POSSIBLE. VFR/WX NIL LATE. SW WINDS.
THURSDAY...MVFR CIGS PSBL IN THE MORNING. W WINDS.
FRIDAY/SATURDAY...VFR/WX NIL. W WINDS.
SUNDAY...LAKE EFFECT SNOW SHOWERS PSBL MAINLY ALONG AND EAST OF
THE TERMINALS WITH MVFR CIGS. OTHERWISE VFR WITH NW WINDS.
KMD
&&
.MARINE...
416 AM CST
A STRONG PRESSURE GRADIENT BETWEEN ARCTIC HIGH PRESSURE IN
SOUTHERN ONTARIO AND DEEP LOW PRESSURE OVER THE ARKLATEX REGION
WILL STRENGTHEN TODAY AS THE LOW SHIFTS NORTHWARD THROUGH THE DAY
AND THE HIGH SHIFTS EASTWARD. GALE FORCE WINDS WILL INCREASE OVER
THE ENTIRE LAKE TODAY...WITH STORM FORCE WINDS EXPECTED FOR A
TIME THIS AFTERNOON AND EARLY EVENING ACROSS THE SOUTHERN HALF OF
THE LAKE.WITH A STRONG EAST FETCH...THESE WINDS LOOK TO AFFECT THE
ILLINOIS NEARSHORE AS WELL. THESE STRONG WINDS WILL RESULT IN
WAVES POSSIBLY REACHING NEAR 20 FT OVER THE SOUTH HALF OF THE
LAKE AND ILLINOIS NEARSHORE. THERE MAY BE A BRIEF PERIOD OF STORM
FORCE GUSTS THIS EVENING ACROSS THE NORTH...BUT HAVE HELD TO THE
GALE WARNING FOR THE NORTH HALF AS THE WINDOW APPEARS TO BE
SHORTER THAN FOR THE SOUTH HALF. THE LOW WILL PUSH NORTHEAST OVER
THE LAKE OVERNIGHT THEN NORTHEAST OF THE LAKE ON TUESDAY...AND
THIS WILL ALLOW WINDS AND WAVES TO SUBSIDE SIGNIFICANTLY AFTER
THIS POINT. MODERATE WESTERLY FLOW WILL CONTINUE OVER THE LAKE
FOR MUCH OF THE LATTER HALF OF THEWEEK.
KMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WINTER STORM WARNING...ILZ013-ILZ014-ILZ021-ILZ022 UNTIL 3 PM
MONDAY.
LAKESHORE FLOOD WARNING...ILZ006-ILZ014...9 AM MONDAY TO
MIDNIGHT TUESDAY.
HIGH WIND WARNING...ILZ006-ILZ014...1 PM MONDAY TO 7 PM MONDAY.
WINTER STORM WARNING...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ019-ILZ020 UNTIL 6 PM MONDAY.
WIND ADVISORY...ILZ013-ILZ021-ILZ022-ILZ023-ILZ032-ILZ033-
ILZ039...9 AM MONDAY TO 6 PM MONDAY.
FLASH FLOOD WATCH...ILZ033-ILZ039 UNTIL 6 PM MONDAY.
FREEZING RAIN ADVISORY...ILZ033-ILZ039 UNTIL NOON MONDAY.
FREEZING RAIN ADVISORY...ILZ023-ILZ032 UNTIL 3 PM MONDAY.
IN...FREEZING RAIN ADVISORY...INZ001-INZ002 UNTIL 3 PM MONDAY.
WIND ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019...9 AM MONDAY
TO 6 PM MONDAY.
FLASH FLOOD WATCH...INZ010-INZ011-INZ019 UNTIL 6 PM MONDAY.
FREEZING RAIN ADVISORY...INZ010-INZ011-INZ019 UNTIL NOON MONDAY.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 6 AM MONDAY.
STORM WARNING...ILLINOIS NEARSHORE WATERS UNTIL 9 PM MONDAY.
GALE WARNING...INDIANA NEARSHORE WATERS UNTIL 9 PM MONDAY.
STORM WARNING...LMZ777-LMZ779 UNTIL MIDNIGHT TUESDAY.
&&
$$
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
417 AM CST MON DEC 28 2015
.SHORT TERM...
401 AM CST
THROUGH TUESDAY...
A MAJOR WIND AND ICE EVENT FOR A GOOD PORTION OF THE AREA...ALONG
WITH SOME OTHER ACCOMPANYING IMPACTS...IS BEGINNING TO UNFOLD INTO
THE REGION EARLY THIS MORNING. NO CHANGES PLANNED TO THE SPATIAL
EXTENT OF THE CURRENT MYRIAD OF HEADLINES...AS THEY COVER THIS
DYNAMIC SYSTEM WELL...WITH JUST SOME MINOR SHIFTS TO TIMING TO
COVER PRIME THREAT TIMES. WE ARE AT THE STAGE NOW OF INCORPORATING
OBSERVATIONAL TRENDS INTO THE GOING FORECAST WITH HOPEFULLY
ADJUSTMENTS MORE SO THAN MAJOR SHIFTS...AND THUS FAR THAT IS THE
CASE. HOWEVER BEING IN A TRANSITIONAL PRECIPITATION EVENT WHERE
SPECIFIC SURFACE AND ALOFT TEMPERATURES PLAY CRITICAL ROLES MAKES
THIS PARTICULARLY CHALLENGING.
THE MOST NOTEWORTHY CHANGES/OBSERVATIONS IN SUMMARY ARE THE OVERALL
FORECAST PRECIPITATION AMOUNTS HAVE BEEN INCREASED AREAWIDE LATE
MORNING THROUGH THE AFTERNOON AS IT IS MORE APPARENT CONVECTIVE
ELEMENTS AND SLANTWISE INSTABILITY WILL IMPINGE INTO THE AREA. THE
OVERLAP AREA OF THESE HEAVIER INTENSITY/AMOUNTS AND THE STILL COLD
ENOUGH FOR FREEZING RAIN APPEARS TO BE ALONG/NORTH OF INTERSTATE
80 AND ALONG AND WEST OF ILLINOIS 47...SO HAVE BUMPED UP FORECAST
ICE ACCUMULATIONS IN THESE AREAS AND PLACED HEAVY WORDING IN THE
FORECAST. HAVE ALSO ADDED ISOLATED/SCATTERED THUNDER...ALTHOUGH
THAT SHOULD BE MAINLY AFTER THE PEAK ICING TIME.
ALSO CONTINUED AN ADJUSTMENT OF A BIT SLOWER TEMPERATURE RECOVERY
IN THE IMMEDIATE LOW-LEVELS RESULTING IN LONGER SLEET DURATION
ALONG AND NORTH OF I-88...WITH THAT POTENTIALLY THE DOMINANT
PRECIPITATION TYPE MOST OF THE MORNING IN THAT REGION. HAVE UPPED
SLEET ACCUMULATION TO AROUND AN INCH THOUGH HIGHER TOTALS
CERTAINLY POSSIBLE DEPENDING ON RATE. WHILE IMPACTS DURING THE
MORNING MAY BE LESS IF THIS MAINLY SLEET/INTERMITTENT SNOW
MATERIALIZES...THE ICING POTENTIAL IN THE AFTERNOON WITH STRONG
WINDS STILL LOOKS ON TRACK.
A VERY POTENT SYSTEM IN ALMOST EVERY DEFINITION IS CENTERED OVER
THE ARKLATEX EARLY THIS MORNING...WHICH WILL HAVE A TRACK RECORD
WHEN IT IS FINISHED LATE TONIGHT WITH AFFECTING ALMOST EVERY
CENTRAL CONUS STATE WITH SOME FORM OF IMPACTING WEATHER. A 70
DEGREE TEMPERATURE DIFFERENCE FROM NORTHWEST IOWA TO NORTHERN
MISSISSIPPI EARLY THIS MORNING HIGHLIGHTS THE BAROCLINICITY THAT
THE WARM AND MOIST ADVECTION IS OVERRIDING INTO OUR AREA.
PRECIPITATION WITH THE LEADING EDGE OF THIS IN THE SOUTHERN CWA
HAS BEEN A LIGHT MIXED BAG THUS FAR. NEAR DAYBREAK INTENSITY LOOKS
TO UPTICK IN RESPONSE TO INCREASING DIFFLUENCE AND LOWER TO MID-
LEVEL F-GEN. THIS WILL CAUSE A PRONOUNCED WET-BULBING COOLING
EFFECT AS INHERENT DRY AIR BECOMES SATURATED WITHIN THE LOW-LEVEL
NORTHEAST FLOW. EARLY MORNING AMDAR DATA NEAR CHICAGO INDICATE A
WARM NOSE AROUND 2C ALOFT AND A LOW-LEVEL COLD NOSE AROUND -5C...
BOTH OF WHICH THE RAP SEEMS TO BE INITIALIZING WELL WITH OVER ITS
PAST FEW RUNS...LENDING SOME CONFIDENCE OF FINE TUNING THE
FORECAST TOWARD IT THIS MORNING. THE VERTICAL PROFILES AND
EXPECTED UPTICK IN PRECIP INTENSITY SHOULD CAUSE THE MAIN TYPE AT
FIRST TO BE ICE PELLETS OR EVEN SOME LIGHT SNOW /WHICH HAS BEEN
REPORTED/. BEING WITHIN THE LOW-LEVEL CONVEYOR BELT OF THIS MATURE
SYSTEM THIS MORNING...WITH 45 KT NORTHEAST 925MB FLOW PER
PROFILERS...THIS SEEMS TO SUPPORT THE TREND FOR P-TYPE TO WANT TO
REMAIN AS SLEET WITH OCCASIONAL SNOW IN FAR NORTHERN PARTS OF THE
CWA INTO LATE MORNING WITH MINOR ACCUMULATIONS. MORE IMPORTANTLY
FOR IMPACTS IT ALSO KEEPS THE FREEZING RAIN CORRIDOR IN PLACE TO
THE SOUTH OF THIS...THROUGH THE MORNING AND EVEN POTENTIALLY EARLY
AFTERNOON. TO HELP VISUALIZE...THIS IS ROUGHLY 30 MILES OR SO
NORTH OR SOUTH OF INTERSTATE 80.
THE AREAS IN THE SHADOW OF THE LAKE...INCLUDING CENTRAL AREAS OF
THE CHICAGO METRO...STILL LOOK LIKE THEY COULD STRUGGLE TO SEE
TEMPERATURES DROP MUCH DUE TO THE STRONG ADVECTION FROM THE
LAKE...SO ICING IS A LITTLE LESS OF A THREAT FOR THESE IMMEDIATE
NEARSHORE LOCATIONS...INCLUDING DOWNTOWN. HOWEVER WIND SPEEDS WILL
BE THE MAXIMUM...GUSTING TO IMPRESSIVE MAGNITUDES TO 50 TO 60 MPH
THIS AFTERNOON AND EARLY EVENING.
THE INGREDIENTS FOR THE WINDS TODAY AND INTO EARLY EVENING CONTINUE
TO JUST BE TRULY STRIKING. PRESSURE FALLS OF AROUND 15MB ARE
FORECAST BETWEEN 10AM AND 3PM OVER MUCH OF THE CWA THIS AFTERNOON.
HAVE CONTINUED WITH FORECAST HIGH END WIND GUSTS AND CORRELATED
DUAL IMPACT WITH ANY ICED LINES AND LIMBS. WIDESPREAD POWER
OUTAGES STILL LOOK POTENTIALLY REALIZED WHERE THE HEAVIER ICE
ACCUMULATIONS OCCUR.
AS THE STACKED SYSTEM CENTER AND ASSOCIATED DEEP TROPOSPHERIC FOLD
MOVES TOWARD THE AREA MID-AFTERNOON...THE WARM MOIST CONVEYOR
BELT NOSE PUSHES INTO THE AREA WITH SOME HEAVY PRECIPITATION AGAIN
LIKELY. ELEVATED INSTABILITY VALUES SUPPORT THUNDER INCLUSION. THE
LOW WILL PASS OVER WITH WINDS THEN EASING. FORCING LOOKS ENOUGH
STILL TO WARRANT SCATTERED RAIN SHOWERS ACROSS THE AREA AND
POSSIBLY EVEN SOME DRIZZLE. THE CHANCE FOR SOME OF THIS TO BE SNOW
SHOWERS INCREASES OVERNIGHT...ALTHOUGH THE INTENSITY SHOULD BE
LIGHT ENOUGH WITH MARGINAL SURFACE TEMPERATURES TO NOT REALLY HAVE
ANY ACCUMULATION. SOME OF THESE SHOWERS MAY LINGER INTO TUESDAY
MORNING...WITH WRAPAROUND COLD ADVECTION KEEPING TEMPERATURES
FROM RISING ANY AND HIGHS IN THE 30S.
MTF
&&
.LONG TERM...
204 AM CST
WEDNESDAY THROUGH SUNDAY...
THE MAIN FEATURE OF THE EXTENDED FORECAST PERIOD IS THE
ESTABLISHMENT OF AN EASTERN NORTH AMERICAN MEAN TROUGH...WITH
UPPER RIDGING BUILDING ACROSS THE NORTHWESTERN U.S. AND WESTERN
CANADA. THIS SETS THE STAGE FOR A PERIOD OF BELOW-AVERAGE COLD
THURSDAY THROUGH SUNDAY...THE FIRST MULTIPLE DAY STRETCH OF
BELOW AVERAGE TEMPERATURES FOR OUR AREA SINCE THE WEEK BEFORE
THANKSGIVING.
BY WEDNESDAY MORNING...THE OCCLUDED SURFACE LOW PRESSURE
ASSOCIATED WITH OUR NEAR TERM WINTER STORM WILL BE FILLING OVER
THE NORTHERN GREAT LAKES...WITH ITS TRAILING COLD FRONT EAST OF
THE FORECAST AREA. ANOTHER MID-LEVEL SHORT WAVE IS PROGGED TO
LIFT OUT OF THE LARGE WESTERN CONUS UPPER TROUGH DURING THE
MORNING...AND EVENTUALLY TAKING THE OLD SURFACE LOW OFF TO THE
NORTHEAST OF THE REGION. 00Z GFS/ECMWF AND GEM RUNS ARE ALL VERY
SIMILAR IN GENERATING AN AXIS OF LIGHT QPF BETWEEN 0.01-0.07"
ACROSS PARTS OF NORTH CENTRAL AND NORTHEAST ILLINOIS DURING THE
MORNING...MAINLY NORTHWEST OF THE I-55 CORRIDOR. USING A MODEL
BLEND QPF AND COBB OUTPUT SNOW/LIQUID RATIOS FROM ROUGHLY 11-13:1
ACROSS THE MAIN QPF AXIS DURING THE PERIOD...SUPPORTING A FEW
TENTHS OF AN INCH OF SNOW ACCUMULATION PERHAPS UP TO A HALF
INCH NORTHWEST OF THE CHICAGO AREA IN THE 12-18Z PERIOD. ONLY A
FEW FLURRIES PERHAPS LINGERING AT MIDDAY/EARLY AFTERNOON.
THE LONG WAVE UPPER TROUGH EVOLVES EASTWARD ACROSS CENTRAL NORTH
AMERICA WEDNESDAY NIGHT AND THURSDAY...EVENTUALLY BECOMING
ELONGATED IN A POSITIVE-TILT SOUTHWEST-NORTHEAST ORIENTATION BY
FRIDAY WITH THE TROUGH AXIS MOVING SOUTHEAST OF THE FORECAST
AREA. AT THE SURFACE...SURFACE LOW PRESSURE ASSOCIATED WITH
WEDNESDAYS DISTURBANCE PULLS AWAY TO THE EAST...WITH A BROAD
REGION OF COLDER WEST-NORTHEAST LOW LEVEL FLOW EAST OF STRONG
SURFACE HIGH PRESSURE DEVELOPING ACROSS THE NORTHERN AND
CENTRAL HIGH PLAINS. WHILE A FEW MINOR AMPLITUDE DISTURBANCES
APPEAR TO MOVE THROUGH THE FLOW ALOFT...LOW LEVELS ARE DOMINATED
BY COLDER...DRIER MODIFIED ARCTIC AIR AND LITTLE IN THE WAY OF
ORGANIZED PRECIP CHANCES ARE NOTED THROUGH THE WEEKEND. COLD
AIR...APPROACHING -10 TO -12 C AT 850 MB BY EARLY FRIDAY...
WILL LIKELY SUPPORT LAKE EFFECT SNOW SHOWERS DOWNWIND OF THE
LAKE ACROSS LOWER MICHIGAN. AS INDICATED ABOVE...THE PERIOD
FROM THURSDAY THROUGH SATURDAY LOOKS TO BE OUR FIRST MULTI-DAY
STRETCH OF BELOW AVERAGE TEMPS IN OVER A MONTH. MODEL LOW LEVEL
THERMAL PROGS AND GFS/ECMWF MOS NUMBERS DEPICT HIGHS IN THE 20S
THUR-FRI WITH LOWS IN THE TEENS AND EVEN A FEW SINGLE DIGITS
IN OUR TYPICALLY COLDEST SPOTS. AVERAGE TEMPS AROUND THE FIRST
OF THE YEAR ARE 30/14 AT ROCKFORD AND 31/17 FOR CHICAGO.
RATZER
&&
.HYDROLOGY...
A POWERFUL STORM SYSTEM WILL DRAW COPIOUS AMOUNTS OF MOISTURE
NORTHWARD ON MONDAY. SOME OF THE PRECIPITATION WILL FALL AS SLEET
AND FREEZING RAIN. TOTAL FORECAST LIQUID EQUIVALENT AMOUNTS ARE IN
THE 1 TO 1.5 INCH RANGE ACROSS NORTHERN AND CENTRAL ILLINOIS AND
NORTHWEST INDIANA. WITH SUCH ANOMALOUSLY HIGH MOISTURE
LEVELS...LOCALLY HIGHER TOTALS ARE PROBABLE. 24-HOUR RAIN AMOUNTS
FROM SATURDAY INTO SUNDAY MORNING WERE UP TO 2-3 INCHES SOUTH OF
THE KANKAKEE RIVER. THIS RAIN HAS ALREADY RESULTED IN RISES ON
RIVERS AND STREAMS IN THIS AREA. THE ADDITIONAL RAIN ON MONDAY
WILL EXACERBATE AND PROLONG ONGOING RISES. FOR AREAS FARTHER
NORTH...RIVER AND STREAM LEVELS ARE ALREADY RUNNING ABOVE
NORMAL...AND THE HEAVY FORECAST PRECIPITATION WILL RESULT IN
RENEWED RISES.
RC
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 09Z...
* MVFR CIGS CONTINUE THROUGH MID-LATE MORNING LOWERING TO IFR BY
LATE MORNING AND INTO LIFR THIS AFTERNOON.
* IFR VSBYS IN PRECIPITATION
* NNE-NE WINDS WITH GUSTS 25-28 KT...VEERING E THIS MORNING WITH
GUSTS 30-35 KT...35-40 KT IN THE AFTERNOON.
* WINTRY MIX OF PCPN...STARTING OUT AS A PERIOD OF PL AND THEN
BECMG FZRAPL. PCPN WILL INTENSIFY BY LATE MORNING THROUGH EARLY
EVENING. PCPN SHOULD TRANSITION TO ALL LIQUID BY EARLY TO MID
AFTERNOON.
* ISOLATED TSRA LATER THIS AFTERNOON.
KMD
//DISCUSSION...UPDATED 06Z...
HAVE SLOWED THE TRANSITION TO FREEZING RAIN IN THE TAFS A LITTLE
BIT. IN SPITE OF THE WARM LAYER ALOFT ADVECTING NORTH (5.5 C PER
THE KILX SOUNDING THIS EVENING)...COLDER AND DRIER LOW LEVEL
ADVECTION FROM THE NORTH IS MAINTAINING WET BULB TEMPERAURES IN
THE LOWEST 100-200 MB BELOW OR CLOSE TO BELOW ZERO. AS
PRECIPITATION ALOFT CONTINUES TO SATURATE THE DRY LAYER BELOW
ABOUT 10000 FT...EXPECT THE MAX TEMPERATURES ALOFT TO COME DOWN TO
CLOSE TO OR SLIGHTLY ABOVE ZERO NORTH OF I-80. HERE WE WOULD
EXPECT PRECIPITATION TO START AS SLEET OR EVEN WITH SOME SNOW
MIXED IN. MEANWHILE SOUTH PRECIPITATION SHOULD LARGELY BE A FZRA
START. CONFIDENCE STILL IS HIGH ON A WINTRY MIX BUT MEDIUM-LOW ON
TRANSITION TIMES GIVEN UNCERTAINTIES IN SURFACE AND LOW LEVEL
TEMPERATURES.
AFTER INITIAL LIGHTER PRECIPITATION...THE FORCING SHOULD INCREASE
SUCH THAT MODERATE PRECIPITATION RATES WOULD BE EXPECTED AS EARLY
AS MID MORNING. EVENTUALLY LATER THIS MORNING THE WARM NOSE ALOFT
SHOULD TRANSITION PRECIPITATION CLOSER TO ALL LIQUID...AND
DEPENDING ON SURFACE TEMPERATURES WILL DETERMINE HOW LONG IT WILL
BE FREEZING RAIN. THIS WILL BE SHORTEST CLOSER TO CHICAGO...LONGER
WESTERN AND NORTHERN AREAS.
THIS AFTERNOON AS WE TRANSITION TO RAIN...SOME INTENSE RATES MAY
OCCUR AS THE DRY SLOT MOVES IN FROM THE SOUTHWEST AND THE DEEP
UPPER LOW APPROACHES. THERE MAY EVEN BE SOME THUNDER IN THE 21Z-
2Z TIME FRAME AS WELL...BUT CONFIDENCE TO LOW FOR A TAF MENTION
JUST YET. OTHERWISE IT IS GOING TO BE VERY WINDY OUT OF THE
ENE...WITH GUSTS MID AFTERNOON APPROACHING 40KT CLOSE TO THE
LAKE...SOLID MID TO UPPER 30 KT GUSTS ELSEWHERE. LIGHTER
RAIN...POSSIBLY MIXED WITH SNOW LATE...IS EXPECTED OVERNIGHT WITH
A SHIFT IN WINDS TO SOUTH THAN SOUTHWEST AFTER MIDNIGHT.
KMD
//ORD AND MDW CONFIDENCE...UPDATED 09Z...
* MEDIUM TO HIGH CONFIDENCE IN GENERAL CIG TRENDS THOUGH MEDIUM ON
TRANSITION TIMES.
* HIGH IN OCCURRENCE OF IFR VSBYS AT TIMES BUT LOW ON THE LENGTH
OF TIME FOR LESS THAN 1SM VSBY.
* HIGH CONFIDENCE IN WIND TRENDS.
* HIGH CONFIDENCE IN A PERIOD OF MIXED PRECIP MONDAY...MEDIUM
CONFIDENCE IN TIMING OF PCPN TYPE CHANGES. MEDIUM HIGH THAT
INITIAL MIXED P-TYPE WOULD BE SLEET AND THAT THE PERIOD OF FZRA
WILL BE SOMEWHAT LIMITED...ESPECIALLY AT MDW.
* MEDIUM CONFIDENCE IN ISOLATED TS THIS AFTERNOON...BUT LOW
CONFIDENCE IN OCCURRENCE AT THE TERMINALS.
KMD
//OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z...
TUESDAY...MVFR CIGS...ESPECIALLY EARLY. SW WINDS. LIGHT RAIN/SNOW
MIX POSSIBLE EARLY.
WEDNESDAY...MVFR CIGS. CHANCE -SN OR -RASN EARLY WITH IFR
POSSIBLE. VFR/WX NIL LATE. SW WINDS.
THURSDAY...VFR/WX NIL. W WINDS.
FRIDAY...VFR/WX NIL. W WINDS.
SATURDAY...VFR/WX NIL. W WINDS.
KREIN
&&
.MARINE...
416 AM CST
A STRONG PRESSURE GRADIENT BETWEEN ARCTIC HIGH PRESSURE IN
SOUTHERN ONTARIO AND DEEP LOW PRESSURE OVER THE ARKLATEX REGION
WILL STRENGTHEN TODAY AS THE LOW SHIFTS NORTHWARD THROUGH THE DAY
AND THE HIGH SHIFTS EASTWARD. GALE FORCE WINDS WILL INCREASE OVER
THE ENTIRE LAKE TODAY...WITH STORM FORCE WINDS EXPECTED FOR A
TIME THIS AFTERNOON AND EARLY EVENING ACROSS THE SOUTHERN HALF OF
THE LAKE.WITH A STRONG EAST FETCH...THESE WINDS LOOK TO AFFECT THE
ILLINOIS NEARSHORE AS WELL. THESE STRONG WINDS WILL RESULT IN
WAVES POSSIBLY REACHING NEAR 20 FT OVER THE SOUTH HALF OF THE
LAKE AND ILLINOIS NEARSHORE. THERE MAY BE A BRIEF PERIOD OF STORM
FORCE GUSTS THIS EVENING ACROSS THE NORTH...BUT HAVE HELD TO THE
GALE WARNING FOR THE NORTH HALF AS THE WINDOW APPEARS TO BE
SHORTER THAN FOR THE SOUTH HALF. THE LOW WILL PUSH NORTHEAST OVER
THE LAKE OVERNIGHT THEN NORTHEAST OF THE LAKE ON TUESDAY...AND
THIS WILL ALLOW WINDS AND WAVES TO SUBSIDE SIGNIFICANTLY AFTER
THIS POINT. MODERATE WESTERLY FLOW WILL CONTINUE OVER THE LAKE
FOR MUCH OF THE LATTER HALF OF THEWEEK.
KMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WINTER STORM WARNING...ILZ013-ILZ014-ILZ021-ILZ022 UNTIL 3 PM
MONDAY.
LAKESHORE FLOOD WARNING...ILZ006-ILZ014...9 AM MONDAY TO
MIDNIGHT TUESDAY.
HIGH WIND WARNING...ILZ006-ILZ014...1 PM MONDAY TO 7 PM MONDAY.
WINTER STORM WARNING...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ019-ILZ020 UNTIL 6 PM MONDAY.
WIND ADVISORY...ILZ013-ILZ021-ILZ022-ILZ023-ILZ032-ILZ033-
ILZ039...9 AM MONDAY TO 6 PM MONDAY.
FLASH FLOOD WATCH...ILZ033-ILZ039 UNTIL 6 PM MONDAY.
FREEZING RAIN ADVISORY...ILZ033-ILZ039 UNTIL NOON MONDAY.
FREEZING RAIN ADVISORY...ILZ023-ILZ032 UNTIL 3 PM MONDAY.
IN...FREEZING RAIN ADVISORY...INZ001-INZ002 UNTIL 3 PM MONDAY.
WIND ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019...9 AM MONDAY
TO 6 PM MONDAY.
FLASH FLOOD WATCH...INZ010-INZ011-INZ019 UNTIL 6 PM MONDAY.
FREEZING RAIN ADVISORY...INZ010-INZ011-INZ019 UNTIL NOON MONDAY.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 6 AM MONDAY.
STORM WARNING...ILLINOIS NEARSHORE WATERS UNTIL 9 PM MONDAY.
GALE WARNING...INDIANA NEARSHORE WATERS UNTIL 9 PM MONDAY.
STORM WARNING...LMZ777-LMZ779 UNTIL MIDNIGHT TUESDAY.
&&
$$
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
409 AM CST MON DEC 28 2015
.SHORT TERM...
401 AM CST
THROUGH TUESDAY...
A MAJOR WIND AND ICE EVENT FOR A GOOD PORTION OF THE AREA...ALONG
WITH SOME OTHER ACCOMPANYING IMPACTS...IS BEGINNING TO UNFOLD INTO
THE REGION EARLY THIS MORNING. NO CHANGES PLANNED TO THE SPATIAL
EXTENT OF THE CURRENT MYRIAD OF HEADLINES...AS THEY COVER THIS
DYNAMIC SYSTEM WELL...WITH JUST SOME MINOR SHIFTS TO TIMING TO
COVER PRIME THREAT TIMES. WE ARE AT THE STAGE NOW OF INCORPORATING
OBSERVATIONAL TRENDS INTO THE GOING FORECAST WITH HOPEFULLY
ADJUSTMENTS MORE SO THAN MAJOR SHIFTS...AND THUS FAR THAT IS THE
CASE. HOWEVER BEING IN A TRANSITIONAL PRECIPITATION EVENT WHERE
SPECIFIC SURFACE AND ALOFT TEMPERATURES PLAY CRITICAL ROLES MAKES
THIS PARTICULARLY CHALLENGING.
THE MOST NOTEWORTHY CHANGES/OBSERVATIONS IN SUMMARY ARE THE OVERALL
FORECAST PRECIPITATION AMOUNTS HAVE BEEN INCREASED AREAWIDE LATE
MORNING THROUGH THE AFTERNOON AS IT IS MORE APPARENT CONVECTIVE
ELEMENTS AND SLANTWISE INSTABILITY WILL IMPINGE INTO THE AREA. THE
OVERLAP AREA OF THESE HEAVIER INTENSITY/AMOUNTS AND THE STILL COLD
ENOUGH FOR FREEZING RAIN APPEARS TO BE ALONG/NORTH OF INTERSTATE
80 AND ALONG AND WEST OF ILLINOIS 47...SO HAVE BUMPED UP FORECAST
ICE ACCUMULATIONS IN THESE AREAS AND PLACED HEAVY WORDING IN THE
FORECAST. HAVE ALSO ADDED ISOLATED/SCATTERED THUNDER...ALTHOUGH
THAT SHOULD BE MAINLY AFTER THE PEAK ICING TIME.
ALSO CONTINUED AN ADJUSTMENT OF A BIT SLOWER TEMPERATURE RECOVERY
IN THE IMMEDIATE LOW-LEVELS RESULTING IN LONGER SLEET DURATION
ALONG AND NORTH OF I-88...WITH THAT POTENTIALLY THE DOMINANT
PRECIPITATION TYPE MOST OF THE MORNING IN THAT REGION. HAVE UPPED
SLEET ACCUMULATION TO AROUND AN INCH THOUGH HIGHER TOTALS
CERTAINLY POSSIBLE DEPENDING ON RATE. WHILE IMPACTS DURING THE
MORNING MAY BE LESS IF THIS MAINLY SLEET/INTERMITTENT SNOW
MATERIALIZES...THE ICING POTENTIAL IN THE AFTERNOON WITH STRONG
WINDS STILL LOOKS ON TRACK.
A VERY POTENT SYSTEM IN ALMOST EVERY DEFINITION IS CENTERED OVER
THE ARKLATEX EARLY THIS MORNING...WHICH WILL HAVE A TRACK RECORD
WHEN IT IS FINISHED LATE TONIGHT WITH AFFECTING ALMOST EVERY
CENTRAL CONUS STATE WITH SOME FORM OF IMPACTING WEATHER. A 70
DEGREE TEMPERATURE DIFFERENCE FROM NORTHWEST IOWA TO NORTHERN
MISSISSIPPI EARLY THIS MORNING HIGHLIGHTS THE BAROCLINICITY THAT
THE WARM AND MOIST ADVECTION IS OVERRIDING INTO OUR AREA.
PRECIPITATION WITH THE LEADING EDGE OF THIS IN THE SOUTHERN CWA
HAS BEEN A LIGHT MIXED BAG THUS FAR. NEAR DAYBREAK INTENSITY LOOKS
TO UPTICK IN RESPONSE TO INCREASING DIFFLUENCE AND LOWER TO MID-
LEVEL F-GEN. THIS WILL CAUSE A PRONOUNCED WET-BULBING COOLING
EFFECT AS INHERENT DRY AIR BECOMES SATURATED WITHIN THE LOW-LEVEL
NORTHEAST FLOW. EARLY MORNING AMDAR DATA NEAR CHICAGO INDICATE A
WARM NOSE AROUND 2C ALOFT AND A LOW-LEVEL COLD NOSE AROUND -5C...
BOTH OF WHICH THE RAP SEEMS TO BE INITIALIZING WELL WITH OVER ITS
PAST FEW RUNS...LENDING SOME CONFIDENCE OF FINE TUNING THE
FORECAST TOWARD IT THIS MORNING. THE VERTICAL PROFILES AND
EXPECTED UPTICK IN PRECIP INTENSITY SHOULD CAUSE THE MAIN TYPE AT
FIRST TO BE ICE PELLETS OR EVEN SOME LIGHT SNOW /WHICH HAS BEEN
REPORTED/. BEING WITHIN THE LOW-LEVEL CONVEYOR BELT OF THIS MATURE
SYSTEM THIS MORNING...WITH 45 KT NORTHEAST 925MB FLOW PER
PROFILERS...THIS SEEMS TO SUPPORT THE TREND FOR P-TYPE TO WANT TO
REMAIN AS SLEET WITH OCCASIONAL SNOW IN FAR NORTHERN PARTS OF THE
CWA INTO LATE MORNING WITH MINOR ACCUMULATIONS. MORE IMPORTANTLY
FOR IMPACTS IT ALSO KEEPS THE FREEZING RAIN CORRIDOR IN PLACE TO
THE SOUTH OF THIS...THROUGH THE MORNING AND EVEN POTENTIALLY EARLY
AFTERNOON. TO HELP VISUALIZE...THIS IS ROUGHLY 30 MILES OR SO
NORTH OR SOUTH OF INTERSTATE 80.
THE AREAS IN THE SHADOW OF THE LAKE...INCLUDING CENTRAL AREAS OF
THE CHICAGO METRO...STILL LOOK LIKE THEY COULD STRUGGLE TO SEE
TEMPERATURES DROP MUCH DUE TO THE STRONG ADVECTION FROM THE
LAKE...SO ICING IS A LITTLE LESS OF A THREAT FOR THESE IMMEDIATE
NEARSHORE LOCATIONS...INCLUDING DOWNTOWN. HOWEVER WIND SPEEDS WILL
BE THE MAXIMUM...GUSTING TO IMPRESSIVE MAGNITUDES TO 50 TO 60 MPH
THIS AFTERNOON AND EARLY EVENING.
THE INGREDIENTS FOR THE WINDS TODAY AND INTO EARLY EVENING CONTINUE
TO JUST BE TRULY STRIKING. PRESSURE FALLS OF AROUND 15MB ARE
FORECAST BETWEEN 10AM AND 3PM OVER MUCH OF THE CWA THIS AFTERNOON.
HAVE CONTINUED WITH FORECAST HIGH END WIND GUSTS AND CORRELATED
DUAL IMPACT WITH ANY ICED LINES AND LIMBS. WIDESPREAD POWER
OUTAGES STILL LOOK POTENTIALLY REALIZED WHERE THE HEAVIER ICE
ACCUMULATIONS OCCUR.
AS THE STACKED SYSTEM CENTER AND ASSOCIATED DEEP TROPOSPHERIC FOLD
MOVES TOWARD THE AREA MID-AFTERNOON...THE WARM MOIST CONVEYOR
BELT NOSE PUSHES INTO THE AREA WITH SOME HEAVY PRECIPITATION AGAIN
LIKELY. ELEVATED INSTABILITY VALUES SUPPORT THUNDER INCLUSION. THE
LOW WILL PASS OVER WITH WINDS THEN EASING. FORCING LOOKS ENOUGH
STILL TO WARRANT SCATTERED RAIN SHOWERS ACROSS THE AREA AND
POSSIBLY EVEN SOME DRIZZLE. THE CHANCE FOR SOME OF THIS TO BE SNOW
SHOWERS INCREASES OVERNIGHT...ALTHOUGH THE INTENSITY SHOULD BE
LIGHT ENOUGH WITH MARGINAL SURFACE TEMPERATURES TO NOT REALLY HAVE
ANY ACCUMULATION. SOME OF THESE SHOWERS MAY LINGER INTO TUESDAY
MORNING...WITH WRAPAROUND COLD ADVECTION KEEPING TEMPERATURES
FROM RISING ANY AND HIGHS IN THE 30S.
MTF
&&
.LONG TERM...
204 AM CST
WEDNESDAY THROUGH SUNDAY...
THE MAIN FEATURE OF THE EXTENDED FORECAST PERIOD IS THE
ESTABLISHMENT OF AN EASTERN NORTH AMERICAN MEAN TROUGH...WITH
UPPER RIDGING BUILDING ACROSS THE NORTHWESTERN U.S. AND WESTERN
CANADA. THIS SETS THE STAGE FOR A PERIOD OF BELOW-AVERAGE COLD
THURSDAY THROUGH SUNDAY...THE FIRST MULTIPLE DAY STRETCH OF
BELOW AVERAGE TEMPERATURES FOR OUR AREA SINCE THE WEEK BEFORE
THANKSGIVING.
BY WEDNESDAY MORNING...THE OCCLUDED SURFACE LOW PRESSURE
ASSOCIATED WITH OUR NEAR TERM WINTER STORM WILL BE FILLING OVER
THE NORTHERN GREAT LAKES...WITH ITS TRAILING COLD FRONT EAST OF
THE FORECAST AREA. ANOTHER MID-LEVEL SHORT WAVE IS PROGGED TO
LIFT OUT OF THE LARGE WESTERN CONUS UPPER TROUGH DURING THE
MORNING...AND EVENTUALLY TAKING THE OLD SURFACE LOW OFF TO THE
NORTHEAST OF THE REGION. 00Z GFS/ECMWF AND GEM RUNS ARE ALL VERY
SIMILAR IN GENERATING AN AXIS OF LIGHT QPF BETWEEN 0.01-0.07"
ACROSS PARTS OF NORTH CENTRAL AND NORTHEAST ILLINOIS DURING THE
MORNING...MAINLY NORTHWEST OF THE I-55 CORRIDOR. USING A MODEL
BLEND QPF AND COBB OUTPUT SNOW/LIQUID RATIOS FROM ROUGHLY 11-13:1
ACROSS THE MAIN QPF AXIS DURING THE PERIOD...SUPPORTING A FEW
TENTHS OF AN INCH OF SNOW ACCUMULATION PERHAPS UP TO A HALF
INCH NORTHWEST OF THE CHICAGO AREA IN THE 12-18Z PERIOD. ONLY A
FEW FLURRIES PERHAPS LINGERING AT MIDDAY/EARLY AFTERNOON.
THE LONG WAVE UPPER TROUGH EVOLVES EASTWARD ACROSS CENTRAL NORTH
AMERICA WEDNESDAY NIGHT AND THURSDAY...EVENTUALLY BECOMING
ELONGATED IN A POSITIVE-TILT SOUTHWEST-NORTHEAST ORIENTATION BY
FRIDAY WITH THE TROUGH AXIS MOVING SOUTHEAST OF THE FORECAST
AREA. AT THE SURFACE...SURFACE LOW PRESSURE ASSOCIATED WITH
WEDNESDAYS DISTURBANCE PULLS AWAY TO THE EAST...WITH A BROAD
REGION OF COLDER WEST-NORTHEAST LOW LEVEL FLOW EAST OF STRONG
SURFACE HIGH PRESSURE DEVELOPING ACROSS THE NORTHERN AND
CENTRAL HIGH PLAINS. WHILE A FEW MINOR AMPLITUDE DISTURBANCES
APPEAR TO MOVE THROUGH THE FLOW ALOFT...LOW LEVELS ARE DOMINATED
BY COLDER...DRIER MODIFIED ARCTIC AIR AND LITTLE IN THE WAY OF
ORGANIZED PRECIP CHANCES ARE NOTED THROUGH THE WEEKEND. COLD
AIR...APPROACHING -10 TO -12 C AT 850 MB BY EARLY FRIDAY...
WILL LIKELY SUPPORT LAKE EFFECT SNOW SHOWERS DOWNWIND OF THE
LAKE ACROSS LOWER MICHIGAN. AS INDICATED ABOVE...THE PERIOD
FROM THURSDAY THROUGH SATURDAY LOOKS TO BE OUR FIRST MULTI-DAY
STRETCH OF BELOW AVERAGE TEMPS IN OVER A MONTH. MODEL LOW LEVEL
THERMAL PROGS AND GFS/ECMWF MOS NUMBERS DEPICT HIGHS IN THE 20S
THUR-FRI WITH LOWS IN THE TEENS AND EVEN A FEW SINGLE DIGITS
IN OUR TYPICALLY COLDEST SPOTS. AVERAGE TEMPS AROUND THE FIRST
OF THE YEAR ARE 30/14 AT ROCKFORD AND 31/17 FOR CHICAGO.
RATZER
&&
.HYDROLOGY...
A POWERFUL STORM SYSTEM WILL DRAW COPIOUS AMOUNTS OF MOISTURE
NORTHWARD ON MONDAY. SOME OF THE PRECIPITATION WILL FALL AS SLEET
AND FREEZING RAIN. TOTAL FORECAST LIQUID EQUIVALENT AMOUNTS ARE IN
THE 1 TO 1.5 INCH RANGE ACROSS NORTHERN AND CENTRAL ILLINOIS AND
NORTHWEST INDIANA. WITH SUCH ANOMALOUSLY HIGH MOISTURE
LEVELS...LOCALLY HIGHER TOTALS ARE PROBABLE. 24-HOUR RAIN AMOUNTS
FROM SATURDAY INTO SUNDAY MORNING WERE UP TO 2-3 INCHES SOUTH OF
THE KANKAKEE RIVER. THIS RAIN HAS ALREADY RESULTED IN RISES ON
RIVERS AND STREAMS IN THIS AREA. THE ADDITIONAL RAIN ON MONDAY
WILL EXACERBATE AND PROLONG ONGOING RISES. FOR AREAS FARTHER
NORTH...RIVER AND STREAM LEVELS ARE ALREADY RUNNING ABOVE
NORMAL...AND THE HEAVY FORECAST PRECIPITATION WILL RESULT IN
RENEWED RISES.
RC
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 09Z...
* MVFR CIGS CONTINUE THROUGH MID-LATE MORNING LOWERING TO IFR BY
LATE MORNING AND INTO LIFR THIS AFTERNOON.
* IFR VSBYS IN PRECIPITATION
* NNE-NE WINDS WITH GUSTS 25-28 KT...VEERING E THIS MORNING WITH
GUSTS 30-35 KT...35-40 KT IN THE AFTERNOON.
* WINTRY MIX OF PCPN...STARTING OUT AS A PERIOD OF PL AND THEN
BECMG FZRAPL. PCPN WILL INTENSIFY BY LATE MORNING THROUGH EARLY
EVENING. PCPN SHOULD TRANSITION TO ALL LIQUID BY EARLY TO MID
AFTERNOON.
* ISOLATED TSRA LATER THIS AFTERNOON.
KMD
//DISCUSSION...UPDATED 06Z...
HAVE SLOWED THE TRANSITION TO FREEZING RAIN IN THE TAFS A LITTLE
BIT. IN SPITE OF THE WARM LAYER ALOFT ADVECTING NORTH (5.5 C PER
THE KILX SOUNDING THIS EVENING)...COLDER AND DRIER LOW LEVEL
ADVECTION FROM THE NORTH IS MAINTAINING WET BULB TEMPERAURES IN
THE LOWEST 100-200 MB BELOW OR CLOSE TO BELOW ZERO. AS
PRECIPITATION ALOFT CONTINUES TO SATURATE THE DRY LAYER BELOW
ABOUT 10000 FT...EXPECT THE MAX TEMPERATURES ALOFT TO COME DOWN TO
CLOSE TO OR SLIGHTLY ABOVE ZERO NORTH OF I-80. HERE WE WOULD
EXPECT PRECIPITATION TO START AS SLEET OR EVEN WITH SOME SNOW
MIXED IN. MEANWHILE SOUTH PRECIPITATION SHOULD LARGELY BE A FZRA
START. CONFIDENCE STILL IS HIGH ON A WINTRY MIX BUT MEDIUM-LOW ON
TRANSITION TIMES GIVEN UNCERTAINTIES IN SURFACE AND LOW LEVEL
TEMPERATURES.
AFTER INITIAL LIGHTER PRECIPITATION...THE FORCING SHOULD INCREASE
SUCH THAT MODERATE PRECIPITATION RATES WOULD BE EXPECTED AS EARLY
AS MID MORNING. EVENTUALLY LATER THIS MORNING THE WARM NOSE ALOFT
SHOULD TRANSITION PRECIPITATION CLOSER TO ALL LIQUID...AND
DEPENDING ON SURFACE TEMPERATURES WILL DETERMINE HOW LONG IT WILL
BE FREEZING RAIN. THIS WILL BE SHORTEST CLOSER TO CHICAGO...LONGER
WESTERN AND NORTHERN AREAS.
THIS AFTERNOON AS WE TRANSITION TO RAIN...SOME INTENSE RATES MAY
OCCUR AS THE DRY SLOT MOVES IN FROM THE SOUTHWEST AND THE DEEP
UPPER LOW APPROACHES. THERE MAY EVEN BE SOME THUNDER IN THE 21Z-
2Z TIME FRAME AS WELL...BUT CONFIDENCE TO LOW FOR A TAF MENTION
JUST YET. OTHERWISE IT IS GOING TO BE VERY WINDY OUT OF THE
ENE...WITH GUSTS MID AFTERNOON APPROACHING 40KT CLOSE TO THE
LAKE...SOLID MID TO UPPER 30 KT GUSTS ELSEWHERE. LIGHTER
RAIN...POSSIBLY MIXED WITH SNOW LATE...IS EXPECTED OVERNIGHT WITH
A SHIFT IN WINDS TO SOUTH THAN SOUTHWEST AFTER MIDNIGHT.
KMD
//ORD AND MDW CONFIDENCE...UPDATED 09Z...
* MEDIUM TO HIGH CONFIDENCE IN GENERAL CIG TRENDS THOUGH MEDIUM ON
TRANSITION TIMES.
* HIGH IN OCCURRENCE OF IFR VSBYS AT TIMES BUT LOW ON THE LENGTH
OF TIME FOR LESS THAN 1SM VSBY.
* HIGH CONFIDENCE IN WIND TRENDS.
* HIGH CONFIDENCE IN A PERIOD OF MIXED PRECIP MONDAY...MEDIUM
CONFIDENCE IN TIMING OF PCPN TYPE CHANGES. MEDIUM HIGH THAT
INITIAL MIXED P-TYPE WOULD BE SLEET AND THAT THE PERIOD OF FZRA
WILL BE SOMEWHAT LIMITED...ESPECIALLY AT MDW.
* MEDIUM CONFIDENCE IN ISOLATED TS THIS AFTERNOON...BUT LOW
CONFIDENCE IN OCCURRENCE AT THE TERMINALS.
KMD
//OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z...
TUESDAY...MVFR CIGS...ESPECIALLY EARLY. SW WINDS. LIGHT RAIN/SNOW
MIX POSSIBLE EARLY.
WEDNESDAY...MVFR CIGS. CHANCE -SN OR -RASN EARLY WITH IFR
POSSIBLE. VFR/WX NIL LATE. SW WINDS.
THURSDAY...VFR/WX NIL. W WINDS.
FRIDAY...VFR/WX NIL. W WINDS.
SATURDAY...VFR/WX NIL. W WINDS.
KREIN
&&
.MARINE...
104 PM CST
A POWERFUL LOW PRESSURE AREA WILL LIFT NORTHWARD THROUGH MISSOURI
AND NEAR OR ALONG THE MISSISSIPPI RIVER VALLEY ON MONDAY. STRONG
1040+ MB HIGH PRESSURE SPREADING IN FROM THE NORTHERN PLAINS
ALREADY RESULTING IN NORTHERLY WINDS UP TO 30 KT ON THE LAKE TODAY
WILL SLIDE EAST TO JUST NORTH OF THE GREAT LAKES ON MONDAY. THE
EXTREMELY TIGHT PRESSURE GRADIENT BETWEEN THE APPROACHING LOW
PRESSURE AND STRONG HIGH PRESSURE WILL RESULT IN EXTREMELY STRONG
EASTERLY WINDS...STARTING ON THE SOUTHERN PART OF THE LAKE AND
THEN SPREADING NORTHWARD MONDAY EVENING AND NIGHT. WILL BE
UPGRADING THE CURRENT STORM WATCH TO A WARNING FOR THE SOUTH HALF
OPEN WATERS AND ILLINOIS NEARSHORE...WHERE THE EASTERLY FETCH WILL
ALSO YIELD PEAK WAVE HEIGHTS OF 15-20 FT OR SO. WILL ALSO UPGRADE
GALE WATCH FOR NORTH HALF AND INDIANA NEARSHORE TO A WARNING.
WINDS/GUSTS MAY FLIRT WITH STORM FORCE ON THE NORTH HALF MONDAY
EVENING INTO THE EARLY PART OF THE OVERNIGHT AND LATER SHIFTS MAY
NEED TO CONSIDER UPGRADING TO A BRIEF STORM WARNING FOR THIS.
WINDS WILL SHIFT TO SOUTHERLY AND DIMINISH MONDAY NIGHT ON THE
SOUTHERN PART OF THE LAKE AS LOW PRESSURE TRACKS NEAR OR JUST WEST
OF THE LAKE...WHILE STRONG EASTERLY WINDS CONTINUE FOR NORTHERN
LAKE MICHIGAN. AFTER THE WEAKENING LOW SHIFTS NORTH OF THE LAKE ON
TUESDAY...MODERATE WESTERLY FLOW WILL SET UP OVER THE LAKE FOR THE
SECOND HALF OF THE WEEK INTO THE WEEKEND.
RC
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WINTER STORM WARNING...ILZ013-ILZ014-ILZ021-ILZ022 UNTIL 1 PM
MONDAY.
LAKESHORE FLOOD WARNING...ILZ006-ILZ014...9 AM MONDAY TO
MIDNIGHT TUESDAY.
HIGH WIND WARNING...ILZ006-ILZ014...1 PM MONDAY TO 7 PM MONDAY.
WINTER STORM WARNING...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ019-ILZ020 UNTIL 6 PM MONDAY.
WIND ADVISORY...ILZ013-ILZ021-ILZ022-ILZ023-ILZ032-ILZ033-
ILZ039...9 AM MONDAY TO 6 PM MONDAY.
FLASH FLOOD WATCH...ILZ033-ILZ039 UNTIL 6 PM MONDAY.
FREEZING RAIN ADVISORY...ILZ023-ILZ032-ILZ033-ILZ039 UNTIL NOON
MONDAY.
IN...FREEZING RAIN ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019
UNTIL NOON MONDAY.
WIND ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019...9 AM MONDAY
TO 6 PM MONDAY.
FLASH FLOOD WATCH...INZ010-INZ011-INZ019 UNTIL 6 PM MONDAY.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 6 AM MONDAY.
STORM WARNING...ILLINOIS NEARSHORE WATERS UNTIL 9 PM MONDAY.
GALE WARNING...INDIANA NEARSHORE WATERS UNTIL 9 PM MONDAY.
STORM WARNING...LMZ777-LMZ779 UNTIL MIDNIGHT TUESDAY.
&&
$$
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AREA FORECAST DISCUSSION
NWS CLEVELAND OH
1011 AM EST MON DEC 28 2015
.SYNOPSIS...
A WARM FRONT WILL BE LIFTING NORTH LATE TODAY AS LOW PRESSURE TRACKS
NORTH-NORTHEAST FROM ARKANSAS TO CENTRAL ILLINOIS. THIS LOW WILL
TRACK ACROSS SOUTHERN MICHIGAN AND INTO ONTARIO CANADA
TONIGHT...TAKING BOTH THE WARM AND COLD FRONTS ACROSS NORTHERN OHIO
AND NW PA. HIGH PRESSURE WILL BRIEFLY RESIDE ACROSS THE OHIO VALLEY
TUESDAY NIGHT. A FEW WEAK DISTURBANCES WILL BE MOVING ACROSS THE
GREAT LAKES FOR THE SECOND HALF OF THE WEEK WITH AN EXPANSIVE AREA
OF HIGH PRESSURE ACROSS THE MIDWEST AND THE LOWER OHIO VALLEY.
&&
.NEAR TERM /THROUGH TONIGHT/...
ONLY CHANGE WITH THIS FORECAST WAS TO EXPAND THE MENTION OF
FREEZING RAIN ACROSS THE CENTRAL HIGHLANDS INTO EARLY AFTERNOON.
AT THIS POINT IN TIME IT APPEARS THAT REGION WILL HAVE A CHANCE OF
FREEZING RAIN FOR THE NEXT COUPLE HOURS THAN TAPER OFF UNTIL THE
WARM FRONT GETS CLOSER. SINCE THE GROUND IS FAIRLY WARM HERE WILL
NOT EXPAND THE ADVISORY TO THIS REGION.
OTHERWISE ALL OTHER HEADLINES WILL REMAIN IN THEIR CURRENT
CONFIGURATIONS.
PREVIOUS DISCUSSION...
COMPLEX SYSTEM HEADED OUR WAY. THE DAY STARTS WITH HIGH PRESSURE SITTING
TO OUR NNW AND A COOL NNE FLOW ACROSS NRN OH/NW PA TO START.
PRECIPITATION CONCERNS HIGHEST AT OUR NW AND NE CORNERS...TOLEDO
AND NW PA.
FIRST ACROSS TOLEDO/NW OH FOR THE FIRST PART OF TODAY...HAVE PUT
UP A WINTER WEATHER ADVISORY FOR TODAY INTO EARLY EVENING. SURFACE
TEMPERATURES WILL BE HOVERING BETWEEN 30 AND 33 DEGREES
TODAY...NOT RISING UNTIL TONIGHT WHEN THE WARM FRONT LIFTS NORTH
AND STRONG SOUTHERLY WINDS BRING WARMER AIR NORTHWARD. EXPECT A
DROP IN TEMPS AS PRECIP STARTS...THEN HOLDING STEADY. BORDERLINE
CONDITIONS BETWEEN SLEET AND FREEZING RAIN. FURTHER TO OUR NORTH
COLD AIR IS DEEPER WITH SLEET MORE LIKELY. TOLEDO IS BORDERLINE.
OHDOT PAVEMENT TEMPS ARE READING AROUND 35 DEGREES...SO IMPACTS
SHOULD BE LESS. BIG QUESTION WILL BE WHEN DO TEMPS REALLY PUSH
ABOVE FREEZING. COULD THE STRONG EASTERLY FLOW OFF OF A LAKE IN
THE 40S BE ENOUGH TO WARM SURFACE TEMPS EARLY OR WILL WE HAVE TO
WAIT FOR THE SOUTHERLY FLOW? ONCE TEMPS GO UP THEY WILL CONTINUE
TO WARM INTO THE LOWER 40S FOR TONIGHT.
ACROSS NW PA...HAVE STARTED THE FREEZING RAIN ADVISORY
SOONER...STARTING IT AT NOON. LATEST HRRR WHICH HAS A GOOD HANDLE
ON CURRENT PICTURE HAS PRECIP MOVING IN FASTER THAN PREVIOUS
FORECAST. ANY PRECIP BEFORE NOON WOULD BE LIGHT. SIMILAR CONCERNS
WITH TEMPERATURES AND WHEN EXACTLY THEY WILL WARM ABOVE FREEZING.
HAVE MADE THAT TRANSITION EARLIER IN THE EVENING...ONLY HANGING ON
TO THE WINTRY PRECIPITATION ACROSS THE FAR EAST. IT IS POSSIBLE
THAT THE FZ RAIN ADV MAY BE ABLE TO END EARLY.
OTHERS MAY SEE SOME SPOTTY/PATCHES OF FREEZING RAIN FIRST THING
THIS MORNING WITH LITTLE OR NO IMPACT. TEMPS MAY BE HARD PRESSED
TO GET MUCH BELOW 32.
RAINFALL AMOUNTS ARE EXPECTED TO BE AROUND A HALF INCH. LOCALLY
HEAVIER AMOUNTS ARE POSSIBLE ESPECIALLY IF WE GET THUNDER UP INTO
THE AREA. HAVE NOT INCLUDED THE THUNDER YET IN THE FORECAST. HAVE
HIGHLIGHTED THE RAINFALL AND POSSIBLE MINOR FLOODING IN THE
HAZARDOUS WEATHER OUTLOOK. AREA CREEKS AND STREAMS WILL CONTINUE
TO RUN HIGH...WITH SOME OF OUR RIVER FORECAST POINTS REACHING INTO
MINOR FLOOD. IF RAINFALL FORECAST NEEDS TO BE INCREASED THEN A
FLOOD WATCH WILL BE NEEDED. RAIN WILL LESSEN DURING THE OVERNIGHT
HOURS...BUT LINGER WITH MOIST CYCLONIC FLOW.
WILL HAVE AN OUTRIGHT STIFF EASTERLY WIND PICK UP FOR THIS
AFTERNOON...COMING AROUND TO THE SE AND SOUTH BY TONIGHT. FOR NOW
HAVE A WIND ADVISORY FOR ERIE COUNTY PA WITH THE ENHANCED
DOWNSLOPE. OTHERS...FOR NOW...WILL HAVE GUSTS OF 35 TO 45 MPH.
TEMPS WILL RISE TONIGHT INTO THE LOWER AND MID 40S. WE MAY EVEN
SEE A 50 OR TWO.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
THE PERSISTENT SOUTHEAST RIDGE WILL BEGIN TO BREAK DOWN THROUGH
THE COURSE OF THE WEEK. NOT A LOT OF COLD AIR BEHIND MONDAY`S
SYSTEM....BUT LOW LEVEL MOISTURE WILL LINGER AND THEREFORE THE
CLOUDS TOO. ANY REMAINING LIGHT RAIN WILL TAPER OFF DURING THE DAY
TUESDAY. A WEAK DISTURBANCE WEDNESDAY WILL GIVE US ANOTHER CHANCE
FOR LIGHT RAIN...WITH SNOW SHOWERS POSSIBLE LATE WEDNESDAY NIGHT
AS THE COLDER AIR FILTERS INTO THE REGION. MID 40S TUESDAY AND
LOWER 40S FOR HIGHS WEDNESDAY. WIDESPREAD TEMPS BELOW FREEZING
WEDNESDAY NIGHT.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
NOT MANY CHANGES AGAIN TODAY AS A MORE WINTRY PATTERN GETS
ESTABLISHED. IT LOOKS LIKE WE WILL SEE SEVERAL DAYS WITH LAKE
EFFECT SNOW POTENTIAL. THE 00Z ECMWF IS A LITTLE QUICKER BRINGING
IN THE COLDER AIR ALOFT ON THURSDAY. THE LAKE EFFECT WILL GET GOING
LATE IN THE DAY AND WILL STICK WITH LIKELY POPS THURSDAY NIGHT.
GIVEN A 260 TO 270 DEGREE FLOW THE SNOW WILL NOT SPREAD VERY FAR
INLAND ACROSS NE OHIO. SOME ACTIVITY IS EXPECTED ON FRIDAY AS WELL.
SATURDAY WILL SEE SOME WEAK WARM AIR ADVECTION WHICH MAY CAUSE THE
PRECIP ACTIVITY TO DIMINISH SOME. A REINFORCING SHOT OF COLD AIR
WILL ARRIVE SATURDAY NIGHT INTO SUNDAY BEHIND ANOTHER TROUGH. WILL
SEE PRECIP CHANCES RAMP UP AGAIN AT THAT TIME. AREAS AWAY FROM THE
SNOWBELT WILL SEE LITTLE MORE THAN A FEW FLURRIES DURING THE PERIOD.
THERE SHOULD BE A FAIR AMOUNT OF CLOUDINESS. TEMPS WILL BE NEAR
NORMAL WITH HIGHS MAINLY IN THE LOW TO MID 30S.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
THE WEATHER IS PRETTY QUIET RIGHT NOW BUT THAT WILL BE CHANGING.
CIGS IN THE EAST HAVE BEEN LIFTING AND THERE COULD BE A PERIOD OF
VFR CIGS THIS MORNING. FURTHER W AND SW PRECIP CONTINUES TO
QUICKLY APPROACH. WITH TEMPS IN THE LOW TO MID 30S JUST ABOUT
EVERYWHERE THERE REMAINS THE POSSIBILITY OF SOME FREEZING
PRECIPITATION. GROUND TEMPS REMAIN WARM BUT METAL SURFACE COULD
SEE SOME SLIGHT GLAZING. BEST CHANCES FOR THIS ARE AT KTOL THIS
MORNING AND KERI EARLY THIS AFTERNOON. EXPECT TEMPS TO WARM
LATER THIS AFTERNOON AS THE WIND PICKS UP A SOUTHERLY COMPONENT.
CIGS MUCH THE MORNING WILL BE MVFR BUT IFR CONDITIONS WILL
DEVELOP ALL AREAS THIS AFTERNOON. EASTERLY WINDS WILL INCREASE
TODAY WITH GUSTS IN EXCESS OF 30 KNOTS POSSIBLE LATER. A DOWNSLOPE
SCENARIO WILL SET UP AT KERI OVERNIGHT WITH WINDS POSSIBLY GUSTING
TO 40 KNOTS. THE SURFACE COLD FRONT WILL SWING ACROSS THE AREA BY
THE END OF THE TAF PERIOD. EXPECT IMPROVING CONDITIONS BEHIND THIS
FRONT.
OUTLOOK...WIDESPREAD NON VFR INTO TUESDAY. NON VFR CONDITIONS
LIKELY AGAIN WEDNESDAY EVENING INTO THURSDAY.
&&
.MARINE...
WILL GO AHEAD AND UPGRADE THE GALE WATCH TO A WARNING FOR
THE WEST HALF OF THE LAKE. DO NOT THINK WE WILL GET SUSTAINED GALES
SO THIS WILL BE A MARGINAL EVENT AND WILL HAVE TO RELY ON THE
FREQUENT GUST CRITERIA. IT APPEARS WATER LEVELS IN THE WEST BASIN
WILL STAY ABOUT A FOOT BELOW LAKESHORE FLOOD WARNING LEVELS.
FORTUNATELY THE NE TO E FETCH WON`T BE PROLONGED WITH SE FLOW
DEVELOPING THIS EVENING. HAVE GONE AHEAD AND EXTENDED THE SMALL
CRAFT IN THE EAST THROUGH TOMORROW. EXPECT THE FLOW TO EVENTUALLY
BECOME SW ON TUESDAY BEHIND THE COLD FRONT. SW TO W FLOW WILL THEN
CONTINUE THROUGH THE END OF THE WEEK. WILL LIKELY NEED SMALL CRAFT
HEADLINES MUCH OF THE WEEK.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR OHZ003-
006.
PA...WIND ADVISORY FROM 10 PM THIS EVENING TO 7 AM EST TUESDAY FOR
PAZ001-002.
FREEZING RAIN ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR PAZ002-
003.
MARINE...GALE WARNING UNTIL 10 PM EST THIS EVENING FOR LEZ142>146-
162>166.
SMALL CRAFT ADVISORY UNTIL 10 PM EST TUESDAY FOR LEZ147>149.
&&
$$
SYNOPSIS...OUDEMAN
NEAR TERM...MULLEN/OUDEMAN
SHORT TERM...OUDEMAN
LONG TERM...KUBINA
AVIATION...KUBINA
MARINE...KUBINA
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
700 AM EST MON DEC 28 2015
.SYNOPSIS...
A WARM FRONT WILL BE LIFTING NORTH LATE TODAY AS LOW PRESSURE TRACKS
NORTH-NORTHEAST FROM ARKANSAS TO CENTRAL ILLINOIS. THIS LOW WILL
TRACK ACROSS SOUTHERN MICHIGAN AND INTO ONTARIO CANADA
TONIGHT...TAKING BOTH THE WARM AND COLD FRONTS ACROSS NORTHERN OHIO
AND NW PA. HIGH PRESSURE WILL BRIEFLY RESIDE ACROSS THE OHIO VALLEY
TUESDAY NIGHT. A FEW WEAK DISTURBANCES WILL BE MOVING ACROSS THE
GREAT LAKES FOR THE SECOND HALF OF THE WEEK WITH AN EXPANSIVE AREA
OF HIGH PRESSURE ACROSS THE MIDWEST AND THE LOWER OHIO VALLEY.
&&
.NEAR TERM /THROUGH TONIGHT/...
NO CHANGES WITH THE EARLY MORNING UPDATE. PRECIP MOVING INTO THE
I-75 CORRIDOR AS OF 7 AM. A FEW LOCATIONS OUTSIDE OF THE WESTERN
ADVISORY AREA MAY DIP DOWN TO 31 OR 32...BUT NOT EXPECTING AN
IMPACT...SHORT DURATION AND ABOVE FREEZING ROAD TEMPS. PREVIOUS
DISCUSSION FOLLOWS...
COMPLEX SYSTEM HEADED OUR WAY. THE DAY STARTS WITH HIGH PRESSURE SITTING
TO OUR NNW AND A COOL NNE FLOW ACROSS NRN OH/NW PA TO START.
PRECIPITATION CONCERNS HIGHEST AT OUR NW AND NE CORNERS...TOLEDO
AND NW PA.
FIRST ACROSS TOLEDO/NW OH FOR THE FIRST PART OF TODAY...HAVE PUT
UP A WINTER WEATHER ADVISORY FOR TODAY INTO EARLY EVENING. SURFACE
TEMPERATURES WILL BE HOVERING BETWEEN 30 AND 33 DEGREES
TODAY...NOT RISING UNTIL TONIGHT WHEN THE WARM FRONT LIFTS NORTH
AND STRONG SOUTHERLY WINDS BRING WARMER AIR NORTHWARD. EXPECT A
DROP IN TEMPS AS PRECIP STARTS...THEN HOLDING STEADY. BORDERLINE
CONDITIONS BETWEEN SLEET AND FREEZING RAIN. FURTHER TO OUR NORTH
COLD AIR IS DEEPER WITH SLEET MORE LIKELY. TOLEDO IS BORDERLINE.
OHDOT PAVEMENT TEMPS ARE READING AROUND 35 DEGREES...SO IMPACTS
SHOULD BE LESS. BIG QUESTION WILL BE WHEN DO TEMPS REALLY PUSH
ABOVE FREEZING. COULD THE STRONG EASTERLY FLOW OFF OF A LAKE IN
THE 40S BE ENOUGH TO WARM SURFACE TEMPS EARLY OR WILL WE HAVE TO
WAIT FOR THE SOUTHERLY FLOW? ONCE TEMPS GO UP THEY WILL CONTINUE
TO WARM INTO THE LOWER 40S FOR TONIGHT.
ACROSS NW PA...HAVE STARTED THE FREEZING RAIN ADVISORY
SOONER...STARTING IT AT NOON. LATEST HRRR WHICH HAS A GOOD HANDLE
ON CURRENT PICTURE HAS PRECIP MOVING IN FASTER THAN PREVIOUS
FORECAST. ANY PRECIP BEFORE NOON WOULD BE LIGHT. SIMILAR CONCERNS
WITH TEMPERATURES AND WHEN EXACTLY THEY WILL WARM ABOVE FREEZING.
HAVE MADE THAT TRANSITION EARLIER IN THE EVENING...ONLY HANGING ON
TO THE WINTRY PRECIPITATION ACROSS THE FAR EAST. IT IS POSSIBLE
THAT THE FZ RAIN ADV MAY BE ABLE TO END EARLY.
OTHERS MAY SEE SOME SPOTTY/PATCHES OF FREEZING RAIN FIRST THING
THIS MORNING WITH LITTLE OR NO IMPACT. TEMPS MAY BE HARD PRESSED
TO GET MUCH BELOW 32.
RAINFALL AMOUNTS ARE EXPECTED TO RANGE FROM A HALF INCH TO ONE
INCH. LOCALLY HEAVIER AMOUNTS ARE POSSIBLE ESPECIALLY IF WE GET
THUNDER UP INTO THE AREA. HAVE NOT INCLUDED THE THUNDER YET IN
THE FORECAST. HAVE HIGHLIGHTED THE RAINFALL AND POSSIBLE MINOR
FLOODING IN THE HAZARDOUS WEATHER OUTLOOK. AREA CREEKS AND STREAMS
WILL CONTINUE TO RUN HIGH...WITH SOME OF OUR RIVER FORECAST POINTS
REACHING INTO MINOR FLOOD. IF RAINFALL FORECAST NEEDS TO BE
INCREASED THEN A FLOOD WATCH WILL BE NEEDED. RAIN WILL LESSEN
DURING THE OVERNIGHT HOURS...BUT LINGER WITH MOIST CYCLONIC FLOW.
WILL HAVE A OUTRIGHT STIFF EASTERLY WIND PICK UP FOR THIS
AFTERNOON...COMING AROUND TO THE SE AND SOUTH BY TONIGHT. FOR NOW
HAVE A WIND ADVISORY FOR ERIE COUNTY PA WITH THE ENHANCED
DOWNSLOPE. OTHERS...FOR NOW...WILL HAVE GUSTS OF 35 TO 45 MPH.
TEMPS WILL RISE TONIGHT INTO THE LOWER AND MID 40S. WE MAY EVEN
SEE A 50 OR TWO.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
THE PERSISTENT SOUTHEAST RIDGE WILL BEGIN TO BREAK DOWN THROUGH
THE COURSE OF THE WEEK. NOT A LOT OF COLD AIR BEHIND MONDAY`S
SYSTEM....BUT LOW LEVEL MOISTURE WILL LINGER AND THEREFORE THE
CLOUDS TOO. ANY REMAINING LIGHT RAIN WILL TAPER OFF DURING THE DAY
TUESDAY. A WEAK DISTURBANCE WEDNESDAY WILL GIVE US ANOTHER CHANCE
FOR LIGHT RAIN...WITH SNOW SHOWERS POSSIBLE LATE WEDNESDAY NIGHT
AS THE COLDER AIR FILTERS INTO THE REGION. MID 40S TUESDAY AND
LOWER 40S FOR HIGHS WEDNESDAY. WIDESPREAD TEMPS BELOW FREEZING
WEDNESDAY NIGHT.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
NOT MANY CHANGES AGAIN TODAY AS A MORE WINTRY PATTERN GETS
ESTABLISHED. IT LOOKS LIKE WE WILL SEE SEVERAL DAYS WITH LAKE
EFFECT SNOW POTENTIAL. THE 00Z ECMWF IS A LITTLE QUICKER BRINGING
IN THE COLDER AIR ALOFT ON THURSDAY. THE LAKE EFFECT WILL GET GOING
LATE IN THE DAY AND WILL STICK WITH LIKELY POPS THURSDAY NIGHT.
GIVEN A 260 TO 270 DEGREE FLOW THE SNOW WILL NOT SPREAD VERY FAR
INLAND ACROSS NE OHIO. SOME ACTIVITY IS EXPECTED ON FRIDAY AS WELL.
SATURDAY WILL SEE SOME WEAK WARM AIR ADVECTION WHICH MAY CAUSE THE
PRECIP ACTIVITY TO DIMINISH SOME. A REINFORCING SHOT OF COLD AIR
WILL ARRIVE SATURDAY NIGHT INTO SUNDAY BEHIND ANOTHER TROUGH. WILL
SEE PRECIP CHANCES RAMP UP AGAIN AT THAT TIME. AREAS AWAY FROM THE
SNOWBELT WILL SEE LITTLE MORE THAN A FEW FLURRIES DURING THE PERIOD.
THERE SHOULD BE A FAIR AMOUNT OF CLOUDINESS. TEMPS WILL BE NEAR
NORMAL WITH HIGHS MAINLY IN THE LOW TO MID 30S.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
THE WEATHER IS PRETTY QUIET RIGHT NOW BUT THAT WILL BE CHANGING.
CIGS IN THE EAST HAVE BEEN LIFTING AND THERE COULD BE A PERIOD OF
VFR CIGS THIS MORNING. FURTHER W AND SW PRECIP CONTINUES TO
QUICKLY APPROACH. WITH TEMPS IN THE LOW TO MID 30S JUST ABOUT
EVERYWHERE THERE REMAINS THE POSSIBILITY OF SOME FREEZING
PRECIPITATION. GROUND TEMPS REMAIN WARM BUT METAL SURFACE COULD
SEE SOME SLIGHT GLAZING. BEST CHANCES FOR THIS ARE AT KTOL THIS
MORNING AND KERI EARLY THIS AFTERNOON. EXPECT TEMPS TO WARM
LATER THIS AFTERNOON AS THE WIND PICKS UP A SOUTHERLY COMPONENT.
CIGS MUCH THE MORNING WILL BE MVFR BUT IFR CONDITIONS WILL
DEVELOP ALL AREAS THIS AFTERNOON. EASTERLY WINDS WILL INCREASE
TODAY WITH GUSTS IN EXCESS OF 30 KNOTS POSSIBLE LATER. A DOWNSLOPE
SCENARIO WILL SET UP AT KERI OVERNIGHT WITH WINDS POSSIBLY GUSTING
TO 40 KNOTS. THE SURFACE COLD FRONT WILL SWING ACROSS THE AREA BY
THE END OF THE TAF PERIOD. EXPECT IMPROVING CONDITIONS BEHIND THIS
FRONT.
OUTLOOK...WIDESPREAD NON VFR INTO TUESDAY. NON VFR CONDITIONS
LIKELY AGAIN WEDNESDAY EVENING INTO THURSDAY.
&&
.MARINE...
WILL GO AHEAD AND UPGRADE THE GALE WATCH TO A WARNING FOR
THE WEST HALF OF THE LAKE. DO NOT THINK WE WILL GET SUSTAINED GALES
SO THIS WILL BE A MARGINAL EVENT AND WILL HAVE TO RELY ON THE
FREQUENT GUST CRITERIA. IT APPEARS WATER LEVELS IN THE WEST BASIN
WILL STAY ABOUT A FOOT BELOW LAKESHORE FLOOD WARNING LEVELS.
FORTUNATELY THE NE TO E FETCH WON`T BE PROLONGED WITH SE FLOW
DEVELOPING THIS EVENING. HAVE GONE AHEAD AND EXTENDED THE SMALL
CRAFT IN THE EAST THROUGH TOMORROW. EXPECT THE FLOW TO EVENTUALLY
BECOME SW ON TUESDAY BEHIND THE COLD FRONT. SW TO W FLOW WILL THEN
CONTINUE THROUGH THE END OF THE WEEK. WILL LIKELY NEED SMALL CRAFT
HEADLINES MUCH OF THE WEEK.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR OHZ003-
006.
PA...WIND ADVISORY FROM 10 PM THIS EVENING TO 7 AM EST TUESDAY FOR
PAZ001-002.
FREEZING RAIN ADVISORY FROM NOON TODAY TO MIDNIGHT EST TONIGHT
FOR PAZ002-003.
MARINE...GALE WARNING FROM 1 PM THIS AFTERNOON TO 10 PM EST THIS
EVENING FOR LEZ142>146-162>166.
SMALL CRAFT ADVISORY UNTIL 10 PM EST TUESDAY FOR LEZ147>149.
&&
$$
SYNOPSIS...OUDEMAN
NEAR TERM...OUDEMAN
SHORT TERM...OUDEMAN
LONG TERM...KUBINA
AVIATION...KUBINA
MARINE...KUBINA
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
626 AM EST MON DEC 28 2015
.SYNOPSIS...
A WARM FRONT WILL BE LIFTING NORTH LATE TODAY AS LOW PRESSURE TRACKS
NORTH-NORTHEAST FROM ARKANSAS TO CENTRAL ILLINOIS. THIS LOW WILL
TRACK ACROSS SOUTHERN MICHIGAN AND INTO ONTARIO CANADA
TONIGHT...TAKING BOTH THE WARM AND COLD FRONTS ACROSS NORTHERN OHIO
AND NW PA. HIGH PRESSURE WILL BRIEFLY RESIDE ACROSS THE OHIO VALLEY
TUESDAY NIGHT. A FEW WEAK DISTURBANCES WILL BE MOVING ACROSS THE
GREAT LAKES FOR THE SECOND HALF OF THE WEEK WITH AN EXPANSIVE AREA
OF HIGH PRESSURE ACROSS THE MIDWEST AND THE LOWER OHIO VALLEY.
&&
.NEAR TERM /THROUGH TONIGHT/...
COMPLEX SYSTEM HEADED OUR WAY. THE DAY STARTS WITH HIGH PRESSURE SITTING
TO OUR NNW AND A COOL NNE FLOW ACROSS NRN OH/NW PA TO START.
PRECIPITATION CONCERNS HIGHEST AT OUR NW AND NE CORNERS...TOLEDO
AND NW PA.
FIRST ACROSS TOLEDO/NW OH FOR THE FIRST PART OF TODAY...HAVE PUT
UP A WINTER WEATHER ADVISORY FOR TODAY INTO EARLY EVENING. SURFACE
TEMPERATURES WILL BE HOVERING BETWEEN 30 AND 33 DEGREES
TODAY...NOT RISING UNTIL TONIGHT WHEN THE WARM FRONT LIFTS NORTH
AND STRONG SOUTHERLY WINDS BRING WARMER AIR NORTHWARD. EXPECT A
DROP IN TEMPS AS PRECIP STARTS...THEN HOLDING STEADY. BORDERLINE
CONDITIONS BETWEEN SLEET AND FREEZING RAIN. FURTHER TO OUR NORTH
COLD AIR IS DEEPER WITH SLEET MORE LIKELY. TOLEDO IS BORDERLINE.
OHDOT PAVEMENT TEMPS ARE READING AROUND 35 DEGREES...SO IMPACTS
SHOULD BE LESS. BIG QUESTION WILL BE WHEN DO TEMPS REALLY PUSH
ABOVE FREEZING. COULD THE STRONG EASTERLY FLOW OFF OF A LAKE IN
THE 40S BE ENOUGH TO WARM SURFACE TEMPS EARLY OR WILL WE HAVE TO
WAIT FOR THE SOUTHERLY FLOW? ONCE TEMPS GO UP THEY WILL CONTINUE
TO WARM INTO THE LOWER 40S FOR TONIGHT.
ACROSS NW PA...HAVE STARTED THE FREEZING RAIN ADVISORY
SOONER...STARTING IT AT NOON. LATEST HRRR WHICH HAS A GOOD HANDLE
ON CURRENT PICTURE HAS PRECIP MOVING IN FASTER THAN PREVIOUS
FORECAST. ANY PRECIP BEFORE NOON WOULD BE LIGHT. SIMILAR CONCERNS
WITH TEMPERATURES AND WHEN EXACTLY THEY WILL WARM ABOVE FREEZING.
HAVE MADE THAT TRANSITION EARLIER IN THE EVENING...ONLY HANGING ON
TO THE WINTRY PRECIPITATION ACROSS THE FAR EAST. IT IS POSSIBLE
THAT THE FZ RAIN ADV MAY BE ABLE TO END EARLY.
OTHERS MAY SEE SOME SPOTTY/PATCHES OF FREEZING RAIN FIRST THING
THIS MORNING WITH LITTLE OR NO IMPACT. TEMPS MAY BE HARD PRESSED
TO GET MUCH BELOW 32.
RAINFALL AMOUNTS ARE EXPECTED TO RANGE FROM A HALF INCH TO ONE
INCH. LOCALLY HEAVIER AMOUNTS ARE POSSIBLE ESPECIALLY IF WE GET
THUNDER UP INTO THE AREA. HAVE NOT INCLUDED THE THUNDER YET IN
THE FORECAST. HAVE HIGHLIGHTED THE RAINFALL AND POSSIBLE MINOR
FLOODING IN THE HAZARDOUS WEATHER OUTLOOK. AREA CREEKS AND STREAMS
WILL CONTINUE TO RUN HIGH...WITH SOME OF OUR RIVER FORECAST POINTS
REACHING INTO MINOR FLOOD. IF RAINFALL FORECAST NEEDS TO BE
INCREASED THEN A FLOOD WATCH WILL BE NEEDED. RAIN WILL LESSEN
DURING THE OVERNIGHT HOURS...BUT LINGER WITH MOIST CYCLONIC FLOW.
WILL HAVE A OUTRIGHT STIFF EASTERLY WIND PICK UP FOR THIS
AFTERNOON...COMING AROUND TO THE SE AND SOUTH BY TONIGHT. FOR NOW
HAVE A WIND ADVISORY FOR ERIE COUNTY PA WITH THE ENHANCED
DOWNSLOPE. OTHERS...FOR NOW...WILL HAVE GUSTS OF 35 TO 45 MPH.
TEMPS WILL RISE TONIGHT INTO THE LOWER AND MID 40S. WE MAY EVEN
SEE A 50 OR TWO.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
THE PERSISTENT SOUTHEAST RIDGE WILL BEGIN TO BREAK DOWN THROUGH
THE COURSE OF THE WEEK. NOT A LOT OF COLD AIR BEHIND MONDAY`S
SYSTEM....BUT LOW LEVEL MOISTURE WILL LINGER AND THEREFORE THE
CLOUDS TOO. ANY REMAINING LIGHT RAIN WILL TAPER OFF DURING THE DAY
TUESDAY. A WEAK DISTURBANCE WEDNESDAY WILL GIVE US ANOTHER CHANCE
FOR LIGHT RAIN...WITH SNOW SHOWERS POSSIBLE LATE WEDNESDAY NIGHT
AS THE COLDER AIR FILTERS INTO THE REGION. MID 40S TUESDAY AND
LOWER 40S FOR HIGHS WEDNESDAY. WIDESPREAD TEMPS BELOW FREEZING
WEDNESDAY NIGHT.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
NOT MANY CHANGES AGAIN TODAY AS A MORE WINTRY PATTERN GETS
ESTABLISHED. IT LOOKS LIKE WE WILL SEE SEVERAL DAYS WITH LAKE
EFFECT SNOW POTENTIAL. THE 00Z ECMWF IS A LITTLE QUICKER BRINGING
IN THE COLDER AIR ALOFT ON THURSDAY. THE LAKE EFFECT WILL GET GOING
LATE IN THE DAY AND WILL STICK WITH LIKELY POPS THURSDAY NIGHT.
GIVEN A 260 TO 270 DEGREE FLOW THE SNOW WILL NOT SPREAD VERY FAR
INLAND ACROSS NE OHIO. SOME ACTIVITY IS EXPECTED ON FRIDAY AS WELL.
SATURDAY WILL SEE SOME WEAK WARM AIR ADVECTION WHICH MAY CAUSE THE
PRECIP ACTIVITY TO DIMINISH SOME. A REINFORCING SHOT OF COLD AIR
WILL ARRIVE SATURDAY NIGHT INTO SUNDAY BEHIND ANOTHER TROUGH. WILL
SEE PRECIP CHANCES RAMP UP AGAIN AT THAT TIME. AREAS AWAY FROM THE
SNOWBELT WILL SEE LITTLE MORE THAN A FEW FLURRIES DURING THE PERIOD.
THERE SHOULD BE A FAIR AMOUNT OF CLOUDINESS. TEMPS WILL BE NEAR
NORMAL WITH HIGHS MAINLY IN THE LOW TO MID 30S.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
THE WEATHER IS PRETTY QUIET RIGHT NOW BUT THAT WILL BE CHANGING.
CIGS IN THE EAST HAVE BEEN LIFTING AND THERE COULD BE A PERIOD OF
VFR CIGS THIS MORNING. FURTHER W AND SW PRECIP CONTINUES TO
QUICKLY APPROACH. WITH TEMPS IN THE LOW TO MID 30S JUST ABOUT
EVERYWHERE THERE REMAINS THE POSSIBILITY OF SOME FREEZING
PRECIPITATION. GROUND TEMPS REMAIN WARM BUT METAL SURFACE COULD
SEE SOME SLIGHT GLAZING. BEST CHANCES FOR THIS ARE AT KTOL THIS
MORNING AND KERI EARLY THIS AFTERNOON. EXPECT TEMPS TO WARM
LATER THIS AFTERNOON AS THE WIND PICKS UP A SOUTHERLY COMPONENT.
CIGS MUCH THE MORNING WILL BE MVFR BUT IFR CONDTIONS WILL DEVELOP
ALL AREAS THIS AFTERNOON. EASTERLY WINDS WILL INCREASE TODAY WITH
GUSTS IN EXCESS OF 30 KNOTS POSSIBLE LATER. A DOWNSLOPE SCENARIO
WILL SET UP AT KERI OVERNIGHT WITH WINDS POSSIBLY GUSTING TO 40
KNOTS. THE SURFACE COLD FRONT WILL SWING ACROSS THE AREA BY THE
END OF THE TAF PERIOD. EXPECT IMPROVING CONDITIONS BEHIND THIS
FRONT.
OUTLOOK...WIDESPREAD NON VFR INTO TUESDAY. NON VFR CONDITIONS
LIKELY AGAIN WEDNESDAY EVENING INTO THURSDAY.
&&
.MARINE...
WILL GO AHEAD AND UPGRADE THE GALE WATCH TO A WARNING FOR
THE WEST HALF OF THE LAKE. DO NOT THINK WE WILL GET SUSTAINED GALES
SO THIS WILL BE A MARGINAL EVENT AND WILL HAVE TO RELY ON THE
FREQUENT GUST CRITERIA. IT APPEARS WATER LEVELS IN THE WEST BASIN
WILL STAY ABOUT A FOOT BELOW LAKESHORE FLOOD WARNING LEVELS.
FORTUNATELY THE NE TO E FETCH WON`T BE PROLONGED WITH SE FLOW
DEVELOPING THIS EVENING. HAVE GONE AHEAD AND EXTENDED THE SMALL
CRAFT IN THE EAST THROUGH TOMORROW. EXPECT THE FLOW TO EVENTUALLY
BECOME SW ON TUESDAY BEHIND THE COLD FRONT. SW TO W FLOW WILL THEN
CONTINUE THROUGH THE END OF THE WEEK. WILL LIKELY NEED SMALL CRAFT
HEADLINES MUCH OF THE WEEK.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR OHZ003-
006.
PA...WIND ADVISORY FROM 10 PM THIS EVENING TO 7 AM EST TUESDAY FOR
PAZ001-002.
FREEZING RAIN ADVISORY FROM NOON TODAY TO MIDNIGHT EST TONIGHT
FOR PAZ002-003.
MARINE...GALE WARNING FROM 1 PM THIS AFTERNOON TO 10 PM EST THIS
EVENING FOR LEZ142>146-162>166.
SMALL CRAFT ADVISORY UNTIL 10 PM EST TUESDAY FOR LEZ147>149.
&&
$$
SYNOPSIS...OUDEMAN
NEAR TERM...OUDEMAN
SHORT TERM...OUDEMAN
LONG TERM...KUBINA
AVIATION...KUBINA
MARINE...KUBINA
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
615 AM EST MON DEC 28 2015
.SYNOPSIS...
A STORM SYSTEM WILL SPREAD PRECIPITATION NORTHEASTWARD ACROSS THE
STATE THIS AFTERNOON AND TONIGHT. TEMPERATURES WILL BE BELOW
FREEZING FOR THE BEGINNING OF THE PRECIPITATION AND MANY AREAS
WILL SEE A WINTRY MIX BEFORE CHANGING OVER TO RAIN TONIGHT.
TUESDAY AND WEDNESDAY WILL BE MILD BUT THE WEATHER REMAINS
UNSETTLED FOR THE REST OF THE WEEK. THE TEMPERATURES WILL TURN
COLDER AND BE DOWN TO SEASONAL NORMALS IN THE SECOND HALF OF THE
WEEK AND INTO THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
615 AM UPDATE...
MADE SOME MINOR TIMING/POP TWEAKS AS THE START OF THE PRECIP
SHOULD BE INTO THE HRRR AND RAP DOMAINS. BOTH OF THESE MESO MODELS
PLAY UP THE SCENARIO ALLUDED TO EARLIER WHERE ONE BAND OF PRECIP
LIFTS STEADILY THRU THE AREA LATE THIS MORNING AND AFTN. A LULL
MAY FOLLOW FOR A FEW HOURS TO THE SOUTH OF THE BAND AS WE MOISTEN
UP FROM TOP-DOWN. WILL KEEP THE START TIME OF THE ADVY THE SAME
SINCE THE INITIAL PRECIP WILL BE VERY LIGHT AND BRIEF.
PREV...
OVERALL...MAIN STORY IS THE PRECIP TYPE AND THINKING HAS NOT
CHANGED FOR THIS FORECAST CYCLE. SLEET...THEN FZRA THEN RAIN.
TIMING IS REALLY CONSISTENT...TOO. THE FAR SRN TIER WILL HAVE THE
LEAST THREAT FOR WINTRY PRECIP AS TEMPS WILL BE MAINLY ABOVE
FREEZING. BUT...THE THREAT FOR A LIGHT COAT OF SLEET AND FREEZING
RAIN HAS PROMPTED A WINT WX ADVY FOR ALMOST ALL OF THE AREA. THE
TROUBLES MAY BE VERY LIMITED AT THE FRINGES OF THE ADVY - IN THE
WRN MTNS BECAUSE THE WINTRY STUFF MAY BE VERY BRIEF OR VERY
ELEVATION-DEPENDENT. THE WARM/WET GROUND AND OBJECTS MAY ALSO NOT
BE CONDUCIVE TO FREEZING RAIN. THIS WOULD BE A GOOD THING. BUT THE
AIR TEMPS DO LOOK TO BE SUB-FREEZING IN MOST PLACES AT THE START.
10Z...RAIN OFF TO THE SOUTH BUT CLOUDS REMAIN AND THE HIGH STUFF
SHOULD BE THICKENING THROUGH THE DAY. THE WINDS ARE ALREADY
STARTING TO GO NORTHEASTERLY AND THE NORTHERN MOUNTAINS ARE INTO
THE 20S. THE LOW CLOUDS OVER THE NRN HALF OF THE AREA MAY BREAK UP
BEFORE THE FIRST WAVE OF PRECIP MOVES IN FROM THE SW. BUT THE
MORE-CLOUDY AREAS WILL NOT COOL TOO MUCH MORE THIS MORNING.
HOWEVER...THE TEMPS MAY NOT RISE AT ALL BEFORE ANY PRECIP MOVES
IN AND STARTS TO WET-BULB/COOL THINGS. MOST AREAS WILL REMAIN
PRECIP-FREE THROUGH 1 OR 2 PM. WHAT MAY ARRIVE BEFORE 3 OR 4 PM
WILL BE VERY LIGHT. MOST GUIDANCE BRINGS THIN BAND OF PRECIP UP
INTO THE SW COS BY NOON AND THEN SPREADS IT ACROSS THE
AREA...MAINLY NW OF IPT/UNV/AOO...THRU THE AFTN AND EARLY EVENING.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/...
COLD AIR DAMMING SCENARIO IN PLACE THIS EVENING WILL YIELD THE
TYPICAL RESULTS. PRECIP WORKS DOWN FROM ABOVE AS THE AIR ALOFT
GETS VERY WARM. THUS...LOTS OF MIX - MAINLY SLEET AT THE ONSET. A
FEW FLAKES CANNOT BE RULED OUT. THEN...THE P-TYPE GOES TO FZRA AND
EVENTUALLY RAIN AS THE BRUTE FORCE ADVECTION OF WARM AIR SCOURS
OUT THE COLD AIR TRAPPED UNDER THE BIG INVERSION. ALL THIS
GENERALLY HAPPENS FROM SW-NE. TIMING UNCHANGED FROM MANY PREV
PACKAGES. MAIN SFC LOW GOES WELL TO THE WEST BUT A SECONDARY LOW
FORMS OVER MD AND MOVES NE WITHOUT MAKING TOO MUCH CHANGE TO THE
PATTERN. IT MAY ENHANCE THE PRECIP AND KEEP THE COLD AIR IN A
LITTLE LONGER THAN WITHOUT THIS DEVELOPMENT. BUT THAT HAS ALREADY
BEEN ACCOUNTED FOR IN THE FCST. PRECIP DIES UP QUICKLY W-E TUESDAY
MORNING. BUT SOME WRAP-AROUND SCT SHRA ARE POSSIBLE /LOW CHC-SCT
POPS/ IN THE SECOND HALF OF THE DAY AND EARLY TUES NIGHT.
TEMPS WARMING OVERNIGHT WILL REACH NEAR 40 IN THE S AND W...BUT BE
CLOSE TO FREEZING IN THE NE. TEMPS CONTINUE TO WARM AS THE
OCCLUDED FRONT MOVES PAST. 8H TEMPS WILL BE FALLING BY MORNING IN
THE NW...BUT BE ABOVE 10C IN THE S/E. THUS MAXES ON TUES WILL
LIKELY BE IN THE MORNING IN THE NW. BUT TEMPS NEAR 40 ARE EXPECTED
THERE BEFORE A SLIGHT SLIDE. MAXES CLOSER TO 50 ARE EXPECTED IN
THE S WHERE ANY ICE WILL HAVE LONG SINCE MELTED AWAY. COOLEST
MAXES WILL BE IN THE NE WHERE FROZEN PRECIP LASTS INTO THE EARLY
PART OF THE DAY. IT WON/T BE ALL THAT WINDY ON TUESDAY.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
TEMPERATURES WILL TURN COLD ENOUGH TUESDAY NIGHT THAT ANY
REMAINING SHOWERS ACROSS THE NORTH MAY TURN TO A FROZEN VARIETY.
THE AIR CALMS DOWN AS HIGH PRESSURE MOVES IN FOR WED MORNING. BUT
THE NEXT WAVE ROLLS ACROSS TO OUR S WED EVENING AS THE STORM
TRACK WILL BE TO OUR SE. SOME REALLY LIGHT RAIN IS POSSIBLE WED
AFTN/NIGHT ON THE POLEWARD SIDE OF THE WEAK WAVE AS IT BECOMES
ENHANCED BY THE POSITIVE INTERACTION OF THE STRONG POLAR JET TO
OUR NW.
COLDER AIR IS THEN IN STROE FOR THE LATTER PART OF THE WEEK.
TEMPS FINALLY GET COLD ENOUGH AND FLOW OUT OF THE W/NW TO GENERATE
LAKE EFFECT SNOW. LAKES TEMPS ARE MOST LIKELY MUCH ABOVE
NORMAL...WHICH SHOULD HELP GENERATE PLENTY OF INSTABILITY AND
MOISTURE FLUX. 8H TEMPS DROP INTO THE NEGATIVE DOUBLE-DIGITS FRI-
MON UNDER A VERY DEEP UPPER TROUGH.
A NRN STREAM COLD FRONT WILL BRING ANOTHER CHANCE OF PCPN AND
REINFORCING SHOT OF COLD AIR NEXT SUNDAY.
&&
.AVIATION /11Z MONDAY THROUGH FRIDAY/...
FOR THE 28/06Z TAFS ISSUED AT 220 AM EST MON DEC 28 2015
SUB-VFR CIGS ARE FOUND MAINLY OVER THE FAR NORTHERN AND WESTERN
AIRSPACE AT 06Z...WITH VFR CONDITIONS AT MOST CENTRAL AND EASTERN
AIRFIELDS. GUIDANCE MAY BE TOO OPTIMISTIC IN IMPROVING SUB-VFR
CIGS THIS MORNING AT BFD/JST. JST IS ONLY IFR SITE WITH CIGS
006V011. AS SFC WINDS SHIFT FROM 360 TO 20-50 DEGREES...IFR CIGS
AT JST SHOULD TREND UP TO MVFR. BFD MAY DIP BELOW 1KFT FOR A TIME
BUT KEPT OVC010 THROUGH 15Z.
MAIN AVN CONCERN WILL BE WINTRY MIX OF PL AND FZRA OVERSPREADING
THE AIRSPACE FROM LATE THIS AFTERNOON THROUGH TONIGHT. CONFIDENCE
IS A LITTLE LOW WITH THE ONSET TIMING BUT HAS BEEN STEADILY
INCREASING FOR WINTRY PTYPES OVER THE PAST 24 HOURS. ALSO STILL
ANTICIPATING LLWS AND WILL ADDRESS THIS WITH THE 12Z TAFS. FZRA
SHOULD TRANSITION TO RAIN BY 15Z TUESDAY.
OUTLOOK...
WED...MVFR/RAIN LKLY 18Z-06Z THU. HIGHEST CONFIDENCE SOUTH.
THU-FRI-...MVFR CIGS NORTH/WEST WITH OCNL IFR IN SHSN. 25-35KT
WIND GUSTS FROM 280-310 ON FRIDAY.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO 10 AM EST
TUESDAY FOR PAZ006-037-041-042.
WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO 4 AM EST
TUESDAY FOR PAZ004-010-017-024>028-033>036-056-057-059-063.
WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO 7 AM EST
TUESDAY FOR PAZ005-011-012-018-019-045-046-049>053-058.
&&
$$
SYNOPSIS...DANGELO
NEAR TERM...DANGELO
SHORT TERM...DANGELO
LONG TERM...DANGELO/GARTNER
AVIATION...STEINBUGL
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
540 AM CST MON DEC 28 2015
.SHORT TERM...(TODAY THROUGH TUESDAY AFTERNOON)
ISSUED AT 339 AM CST MON DEC 28 2015
MODELS SEEMS TO HAVE CONVERGED TOWARDS AN AGREEABLE SOLN THIS
MORNING...PIVOTING THE UPPER LOW THROUGH EASTERN MISSOURI AND INTO
NORTHERN MICHIGAN BY TUESDAY MORNING. THIS MARKS A SLIGHTLY MORE
EASTWARD TRAJECTORY THAN PREVIOUSLY ADVERTISED...LIKELY DUE TO SOME
IMPACT FROM CONVECTION ASSOCIATED WITH THE WAVE. THE OVERALL
CONSENSUS PLACES THE TRACK OF THIS WAVE SLIGHTLY FURTHER WEST THAN
THE GFS/NAM...AND MORE ALONG THE LINE OF THE ECMWF/GEM.
PRECIPITATION ALREADY ONGOING OVER THE LOWER MO RIVER VALLEY WILL
CONTINUE TO PRESS NORTHWARD TOWARDS THE CWA BY MID-MORNING.
STRONG DIVERGENCE ALOFT COMBINED WITH BROAD BUT INTENSE LOW LEVEL
WARM ADVECTION SHOULD SEND A BROAD AREA OF LIGHT TO MODERATE SNOWS
NORTHWARD THROUGH THE DAY. HRRR SUGGESTS INITIAL BANDS REACH SIOUX
CITY AND STORM LAKE BY 8AM...THE I-90 CORRIDOR BY NOON...AND THE
NORTHERN CWA AFTER MID-AFTERNOON.
MODELS ALSO GRASPING SLIGHTLY BETTER AT WEAKER PV ANOMALY OVER
NORTHERN KANSAS AND SOUTH CENTRAL NEBRASKA. THIS WAVE WILL PIVOT
NORTHEAST WITH THE STRONGER EASTERN LOW BY MONDAY NIGHT...AND
CONTINUES TO SHOW SIGNS OF INTENSIFICATION GIVEN NICE JET STREAK
ALOFT. I DO HAVE SOME CONCERNS ABOUT THE IMPACT OF A DRY INTRUSION
OF AIR WITH THE 700:600 MB LAYER ADVERTISED BY THE NAM ARRIVING FROM
THE SOUTHWEST THIS AFTERNOON. THIS HAS POTENTIAL TO REALLY LIMIT
SNOWFALL RATES DURING THE SECOND HALF OF THE AFTERNOON.
MOVING AHEAD...THIS SECONDARY PV ANOMALY MAY LINGER JUST NORTH OF
THE TRI-STATE AREA WELL INTO TUESDAY AND GIVEN UPR DYNAMICS...SHOULD
SUPPORT A LONGER DURATION SNOWFALL OVER THE NORTHERN AND
NORTHEASTERN CWA INTO TUESDAY AFTERNOON.
WHILE QPF AMOUNTS HAVE TRENDED DOWNWARD...SLR VALUES HAVE
TRENDED UPWARDS SLIGHTLY. INITIAL ONSET OF PRECIPITATION MAY SEE 12-
13:1 RATIOS WITH VALUES INCREASING TOWARDS THE 14-15:1 RATIO THROUGH
THE NIGHT. THESE VALUES PUSH THE HIGHEST SNOWFALL TOTALS OVER THE
FAR EASTERN CWA...WITH THE HIGHEST CONCENTRATION OF 6 INCH OR HIGHER
REPORTS OVER MINNESOTA/IOWA COUNTIES. ELSEWHERE...A LONGER DURATION
2 TO 6 INCH SNOWFALL SEEMS LIKELY.
AS FAR AS HEADLINES ARE CONCERNED...WILL PUSH WARNING SLIGHTLY
FURTHER NORTH INTO THE MARSHALL AREA GIVEN POTENTIAL OF 6 - 8 INCHES
OVER 24 HOURS AND IMPACTS FROM WINDS. WILL ALSO ISSUE AN ADVISORY
FOR THE REMAINING AREAS ALONG AND WEST OF I-29. WHILE SNOWFALL
TOTALS ARE SLIGHTLY LOWER...THROUGH COLLABORATION...WILL LEAVE
WARNING IN PLACE FOR NERN NEBRASKA AND FAR SOUTHEASTERN SD COUNTIES.
.LONG TERM...(TUESDAY EVENING THROUGH SUNDAY)
ISSUED AT 339 AM CST MON DEC 28 2015
SNOW WILL BE LIGHT AND BECOMING SPOTTY BY TUESDAY EVENING AND BE
CONCENTRATED IN THE NORTHERN PART OF OUR FORECAST AREA. IN FACT...IT
MAY QUICKLY WEAKEN TO SCATTERED FLURRIES. WILL STILL CARRY THE
LOW...MOSTLY SLIGHT CHANCE POPS...WE HAVE BEEN GOING WITH IN THE
FLAT UPPER FLOW BEHIND THE MAIN SYSTEM. ANY LINGERING FLAKES SHOULD
END WEDNESDAY. AMOUNTS IF ANY WILL BE A HALF INCH OR LESS. LOW
LEVEL.SURFACE FLOW AND WINDS WILL BE NORTHWESTERLY AND SHOULD BE
FAIRLY LIGHT. EXPECT PLENTY OF CLOUDS TO REMAIN THROUGH WEDNESDAY.
TEMPERATURES FOR THE TIME WILL SHOW A SMALL DIURNAL RANGE WITH ABOVE
NORMAL LOWS AND BELOW NORMAL HIGHS.
A DRYING PROCESS IS EXPECTED TO ACCOMPANY A GRADUALLY DEVELOPING
NORTHWESTERLY FLOW ALOFT AND AT THE SURFACE STARTING WEDNESDAY NIGHT
AND THURSDAY. THIS DRY TREND SHOULD CONTINUE THROUGH THE WEEKEND.
TEMPERATURES WILL WARM SOME ON HIGHS WITH THE WARMING TREND OF
COURSE MODIFIED BY SNOW COVER. LOWS SHOULD STAY THE SAME
OR COOL A BIT. WILL GO WITH THE EXTENDED GUIDANCE TEMPERATURES FOR
NOW BUT THINK THEY COULD BE UNDER DOING THE DIURNAL RANGES...
MAINLY ON FORECAST LOWS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 540 AM CST MON DEC 28 2015
VFR WILL LOWER FROM THE SOUTHEAST TO CEILINGS 1-2K FEET AND
VISIBILITIES 3-5SM IN SNOW 14Z-02Z. FURTHER LOWERING TO CEILINGS
BELOW 1K FEET AND VISIBILITIES BELOW 3SM IN SNOW WILL TAKE PLACE
WITHIN 2-3 HOURS OF SNOW BEGINNING. IMPROVEMENT BACK TO
VISIBILITIES 3-5SM IN LIGHT SNOW WILL TAKE PLACE SOUTH ON
INTERSTATE 90 29/06Z-12Z.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...WINTER WEATHER ADVISORY FROM NOON TODAY TO NOON CST TUESDAY FOR
SDZ060>069.
WINTER STORM WARNING FROM 9 AM THIS MORNING TO 9 AM CST TUESDAY
FOR SDZ070-071.
WINTER WEATHER ADVISORY FROM NOON TODAY TO 6 PM CST TUESDAY FOR
SDZ040-055-056.
WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 6 PM CST
TUESDAY FOR SDZ038-039-052>054-057>059.
MN...WINTER WEATHER ADVISORY FROM NOON TODAY TO 6 PM CST TUESDAY FOR
MNZ071.
WINTER STORM WARNING FROM NOON TODAY TO 6 PM CST TUESDAY FOR
MNZ072-080-081-089-090-097-098.
IA...WINTER STORM WARNING FROM 9 AM THIS MORNING TO 9 AM CST TUESDAY
FOR IAZ001>003-012>014-020>022-031-032.
NE...WINTER STORM WARNING FROM 9 AM THIS MORNING TO 9 AM CST TUESDAY
FOR NEZ013-014.
&&
$$
SHORT TERM...DUX
LONG TERM...
AVIATION...
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
919 AM CST MON DEC 28 2015
.UPDATE...
.MARINE...
VERY STRONG PRESSURE GRADIENT ASSOCIATED WITH LOW PRESSURE OVER
ARKANSAS WILL RESULT IN EXTREMELY WINDY CONDITIONS OVER THE
NEARSHORE WATERS TODAY INTO TONIGHT. WIND SPEEDS WILL CONTINUE TO
INCREASE INTO THE EARLY AFTERNOON WITH STORM FORCE GUSTS OF 48 TO 50
KNOTS EXPECTED. THIS STRONG ONSHORE FLOW WILL CAUSE HIGH WAVES OF 9
TO 13 FEET THIS AFTN AND EVE. MARINE TRAVEL IS STRONGLY NOT
RECOMMENDED. A STORM WARNING REMAINS IN EFFECT THROUGH THIS
EVENINIG.
THE WINDS WILL RAPIDLY DECREASE LATER TONIGHT AS THE LOW PRESSURE
SYSTEM MOVES ACROSS SOUTHERN WISCONSIN AND LAKE MICHIGAN.
WILL CONTINUE LAKESHORE FLOOD ADVISORY AS ONSHORE WINDS WILL LIKELY
GUST AS HIGH AS 50 MPH THIS AFTERNOON AND EARLY EVENING.WAVE HEIGHTS
CRASHING ONSHORE MAY REACH 11-13 FEET DURING THIS TIME. SOME BEACH
EROSION MAY OCCUR ALONG WITH DAMAGE TO STRUCTURES. EMPHASIZE
REMAINING AWAY FROM THE LAKE MICHIGAN SHORE BY THEWATERS FOR SAFETY.
&&
.PREV DISCUSSION... /ISSUED 913 AM CST MON DEC 28 2015/
UPDATE...
SNOW ALREADY DEVELOPED ACROSS SOUTHERN WI THIS MORNING. THAT DRY
LAYER IN THE LOW LEVELS ERODED QUICKLY. RAP AND OTHER MODEL
SOUNDINGS SUPPORT SNOW/SLEET THROUGH THE MORNING HOURS. THIS MEANS
WE WILL NEED TO INCREASE SNOWFALL AMOUNTS THROUGH 20Z. WE COULD SEE
AN INCH BUT I AM STILL WORKING ON THE DETAILS.
THE WARM LAYER WITH +5C ALOFT WILL LIFT INTO SOUTHEAST WI AFTER
20Z/2 PM THIS AFTERNOON WHICH WILL PRODUCE MORE FREEZING RAIN AND
LESS SLEET... POSSIBLY RAIN DEPENDING ON THE SURFACE TEMPERATURE AT
THAT TIME. THAT WARM LAYER WILL ONLY BE -3C TO -4C IN MADISON SO
EXPECT MORE SLEET THERE. TOWARD THE DELLS... THE WARM LAYER ONLY
REACHES +1 OR LESS... SO WE CAN EXPECT ALMOST ALL SNOW THERE WITH A
MIX OF SLEET. THE AFTERNOON HOURS WILL BE THE TIME OF HEAVIEST
PRECIP.
THE DEEP COLD LAYER WITH MIN TEMP OF -5C TO -6 C IN THE LOWEST 4000
FEET SEEMS CONSISTENT ACROSS ALL OF SOUTHERN WI. THIS COLD LAYER
WILL HELP TO RE-FREEZE THE LIQUID PRODUCED FROM THE WARM LAYER INTO
SLEET OR FREEZING RAIN. IT MIGHT NOT BE SUFFICIENTLY COLD TO FREEZE
IT INTO ALL SLEET IN SOUTHEAST WI GIVEN THE DEPTH OF THE WARM
LAYER... SO FREEZING RAIN IS A BIG CONCERN.
WIND IS THE OTHER BIG STORY TODAY. THE WIND WILL HELP TO REDUCE
VISIBILITY IN SNOW AND SLEET. VISIBILITY COULD BE REDUCED TO A
QUARTER MILE OR LESS AT TIMES THIS AFTERNOON. WIND WILL ALSO
INCREASE RISK OF DOWNED TREES AND POWER LINES WITH FREEZING RAIN
ACCUMULATION.
I AM WORKING TO INCREASE SNOWFALL/SLEET AMOUNTS THIS MORNING AND
WILL CONTINUE TO UPDATE WEATHER TYPES. BOTTOM LINE IS THAT TRAVEL
WILL BE DIFFICULT... LAWN ORNAMENTS WILL BLOW AROUND... AND EXPECT
A VERY TREACHEROUS AFTERNOON COMMUTE.
PREV DISCUSSION... /ISSUED 347 AM CST MON DEC 28 2015/
TODAY AND TONIGHT...FORECAST CONFIDENCE MEDIUM.
MODELS ARE A LITTLE MORE IN LINE WITH THE SURFACE TRACK WITH THE GFS
STILL A LITTLE MORE SOUTH AND EAST. THE NAM IS SIMILAR TO THE ECMWF
BUT THE ECMWF IS A LITTLE FARTHER WEST LIKE THE HIGH RESOLUTION MESO
MODELS ESPECIALLY THE HRRR.
PRECIPITATION SHOULD REACH THE GROUND ALONG THE ILLINOIS BORDER AREA
AROUND 9AM CST AND REACH THE FOND DU LAC AND SHEBOYGAN AREAS JUST
AFTER 1 PM.
THIS WILL BE A VERY WET SYSTEM WITH PRECIPITABLE WATER VALUES UP
0.90 INCH BEING DRIVEN BY A 50 KNOT LOW LEVEL JET AHEAD OF A
COMPACT...OCCLUDING LOW PRESSURE SYSTEM. THERE WILL BE VERY STRONG
SYNOPTIC FORCING WITH THIS SYSTEM... WITH LAYER Q-VECTOR CONVERGENCE
OF 20 TO 50 UNITS AND VERY STRONG OMEGA DURING THE AFTERNOON
AND EARLY EVENING TIME PERIOD. WE ARE EXPECTING 0.50 TO 0.75 INCH OF
QPF/LIQUID PRECIP WITHIN 6 HOURS MONDAY AFTERNOON. THE BIG QUESTION
CONTINUES TO BE PRECIP TYPE.
ALTHOUGH THE GFS IS STILL COOLER WITH THE THERMAL PROFILES...MOST
MODELS ARE KEYING ON SLEET BEING THE BIGGEST FACTOR WITH THIS STORM
OVER THE FORECAST AREA...WITH FREEZING RAIN ALSO A CONCERN...EXCEPT
FAR EAST NEAR LAKE MICHIGAN WITH THE WARMER LAKE WATERS. FARTHER
WEST AND NORTH MORE OF A SNOW MIX IS EXPECTED. DUE TO EVAPORATIVE
COOLING MANY AREAS COULD SEE SOME SNOW INITIALLY.
AS THE LOW APPROACHES THE PRECIPITATION WILL TURN MORE RAIN IN THE
FAR SOUTHEAST...THEN A VARIETY OF DRIZZLE TYPES NEAR THE LOW. SOME
TRANSITION BACK TO LIGHT SNOW AS THE MID LEVEL LOW MOVES OVER.
STRONG EAST WINDS WILL FURTHER EXACERBATE TRAVEL CONDITIONS WITH
PERIODS OF WHITEOUT CONDITIONS IN THE MORE SNOW AREAS WEST OF
MADISON AND POTENTIAL IMPACTS FROM UP TO 0.10 TO 0.20 INCH OF
FREEZING RAIN. THUS A WINTER STORM WARNING CONTINUES FOR ALL OF
SOUTHERN AND EAST CENTRAL WISCONSIN.
GUSTY EAST WINDS WILL STEADILY INCREASE THIS MORNING AND BECOME VERY
STRONG BY MONDAY AFTERNOON. WIND GUSTS OF 40 TO 45 MPH
LIKELY...WITH SOME 50 MPH GUSTS POSSIBLE ESPECIALLY HIGH AREAS AND
NEAR LAKE MICHIGAN.
TUESDAY - CONFIDENCE...MEDIUM
LINGERING MID LEVEL CYCLONIC FLOW AS FIRST WAVE LIFTS NORTHEAST FROM
SRN WI AND SECONDARY WAVE SHIFTS SLOWLY NE FROM SRN MN VCNTY. BY
AFTERNOON MID LEVEL FLOW EXPECTED TO BR BROADLY ANTICYCLONIC.
SFC/850 CONVERGENCE PERSISTS IN THE MORNING AS LOW WEAKENS FURTHER
AND SHIFTS NE AWAY FROM LWR MI VCNTY. CONVERGENCE WEAKENS DURG THE
AFTN AND SHIFTS NORTH AWAY FROM SRN WI. MODELS ARE ALL SHOWING
SOME LIGHT QPF PERSISTING DURG THE MRNG HRS. OF PARTICULAR CONCERN
IS THE MID LEVEL DRYING WHICH RESULTS IN THE LOSS OF SATURATION
WITHIN THE DENDRIDIC GROWTH ZONE. SO EXPECT SOME FREEZING DRIZZLE
IN THIS SCENARIO. HIGHEST POPS WILL BE IN THE MORNING WITH A SHIFT
TOWARDS CONFINING POPS TO THE THE NORTHERN REACHES OF THE CWA FOR
THE AFTN HRS. LLVL RH PROGS KEEP THINGS MOIST SO STAYING
PESSIMISTIC WRT CLOUD COVER.
WEDNESDAY - CONFIDENCE...MEDIUM
ELONGATED VORT AXIS THEN PROGGD TO SHIFT NE FROM BASE OF WRN
TROUGH. NOT MUCH IN THE WAY OF A SFC REFLECTION TO THIS THOUGH A
SFC/850 TROUGH LIKELY TO AID IN SOME VERTICAL MOTION. QPF AMOUNTS
ARE LIGHT AND IN THIS CASE WE ARE SEEING ENOUGH SATURATION IN THAT
DENDRIDIC GROWTH ZONE TO GO WITH ALL SNOW ON THE PRECIP TYPE. SO
OVERALL LOOKS LIKE SOME AREAS SEE A 1/2 INCH OF SNOW.. THE GFS HAS
A SMIDGE HIGHER QPF THAT WOULD PERHAPS PUSH AN INCH BUT WILL GO
WITH MORE OF A CONSENSUS APPROACH WRT QPF AT THIS TIME.
THURSDAY THROUGH SUNDAY - CONFIDENCE...MEDIUM
OVERALL QUIET NW FLOW REGIME. GFS SUGGESTS SOME SHSN POTENTIAL
FOR THU BUT ECMWF IS DRY AND SUPERBLEND POPS LEAN THIS WAY. MAY
NEED A SMALL POP OR SOME FLURRIES EVENTUALLY BUT FOR NOW WILL KEEP
THINGS DRY. 925 TEMPS SUPPORT HIGHS MOSTLY IN THE 20S TO LOW 30S.
AVIATION/12Z TAFS/...
AVIATION/12Z TAFS/...THE EAST WINDS HAVE PUSHED AN MVFR CLOUD DECK
ACROSS MUCH OF SOUTHERN WISCONSIN DUE TO MOISTURE OFF LAKE MICHIGAN.
A STRONG LOW WILL MOVE ACROSS THE MID MISSISSIPPI VALLEY AND INTO
NORTHERN ILLINOIS THIS EVENING. PRECIPITATION WILL SPREAD NORTH.
INITIALLY DRY AIR WILL CAUSE VIRGA...BUT THE STRONG VERTICAL MOTION
WILL CAUSE PRECIPITATION TO REACH THE GROUND MID MORNING FAR SOUTH
AND TOWARDS NOON NEAR FOND DU LAC AND SHEBOYGAN. A WARM SURGE
AROUND 7 TO 9 THSD FT WILL CAUSE A MIX OF PRECIPITATION TO DEVELOP
WITH SLEET THE PREDOMINATE TYPE MOST AREAS. SOME FREEZING RAIN WILL
LATER THIS AFTERNOON INLAND AREAS. SNOW MAY FALL WITH THE ONSET AND
ALSO A MIX OF SNOW AND SLEET ESPECIALLY NORTH AND WEST OF
MADISON.
CIGS/VSBYS BECOMING IFR/LIFR THIS AFTERNOON AND EVENING.
NORTHEAST WINDS WILL VEER EAST...INCREASING TO 30 KNOTS MID-LATE
MORNING AND 40 KNOTS IN THE AFTERNOON...WITH 45 KNOT GUSTS IN THE
FAR EAST.
MARINE...WILL UPGRADE TO A STORM WARNING. HIGHEST STORM FORCE
GUSTS EXPECTED LATE AFTERNOON AND EARLY EVENING.
LATEST HIGH RESOLUTION HRRR EXPERIMENTAL SUPPORTS A HIGH-END GALE
WARNING...WITH STORM FORCE GUSTS LIKELY LATE AFTERNOON AND EARLY
EVENING. WILL OBVIOUSLY NEED A SMALL CRAFT ADVISORY FOR A TIME
OVERNIGHT MONDAY NIGHT AND TUESDAY AFTER THE GALE WARNING EXPIRES
AND THE LOW MOVES INTO SOUTHERN LAKE MICHIGAN DIMINISHING THE
WINDS.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...WINTER STORM WARNING UNTIL 6 AM CST TUESDAY FOR WIZ062>072.
LAKESHORE FLOOD ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR WIZ052-
060-066-071-072.
WINTER STORM WARNING UNTIL 6 AM CST TUESDAY FOR WIZ046-047-051-
052-056>060.
LM...STORM WARNING UNTIL 10 PM CST THIS EVENING FOR LMZ643>646.
&&
$$
UPDATE...MBK
TODAY/TONIGHT AND AVIATION/MARINE...HENTZ
TUESDAY THROUGH SUNDAY...COLLAR
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
913 AM CST MON DEC 28 2015
.UPDATE...
SNOW ALREADY DEVELOPED ACROSS SOUTHERN WI THIS MORNING. THAT DRY
LAYER IN THE LOW LEVELS ERODED QUICKLY. RAP AND OTHER MODEL
SOUNDINGS SUPPORT SNOW/SLEET THROUGH THE MORNING HOURS. THIS MEANS
WE WILL NEED TO INCREASE SNOWFALL AMOUNTS THROUGH 20Z. WE COULD SEE
AN INCH BUT I AM STILL WORKING ON THE DETAILS.
THE WARM LAYER WITH +5C ALOFT WILL LIFT INTO SOUTHEAST WI AFTER
20Z/2 PM THIS AFTERNOON WHICH WILL PRODUCE MORE FREEZING RAIN AND
LESS SLEET... POSSIBLY RAIN DEPENDING ON THE SURFACE TEMPERATURE AT
THAT TIME. THAT WARM LAYER WILL ONLY BE -3C TO -4C IN MADISON SO
EXPECT MORE SLEET THERE. TOWARD THE DELLS... THE WARM LAYER ONLY
REACHES +1 OR LESS... SO WE CAN EXPECT ALMOST ALL SNOW THERE WITH A
MIX OF SLEET. THE AFTERNOON HOURS WILL BE THE TIME OF HEAVIEST
PRECIP.
THE DEEP COLD LAYER WITH MIN TEMP OF -5C TO -6 C IN THE LOWEST 4000
FEET SEEMS CONSISTENT ACROSS ALL OF SOUTHERN WI. THIS COLD LAYER
WILL HELP TO RE-FREEZE THE LIQUID PRODUCED FROM THE WARM LAYER INTO
SLEET OR FREEZING RAIN. IT MIGHT NOT BE SUFFICIENTLY COLD TO FREEZE
IT INTO ALL SLEET IN SOUTHEAST WI GIVEN THE DEPTH OF THE WARM
LAYER... SO FREEZING RAIN IS A BIG CONCERN.
WIND IS THE OTHER BIG STORY TODAY. THE WIND WILL HELP TO REDUCE
VISIBILITY IN SNOW AND SLEET. VISIBILITY COULD BE REDUCED TO A
QUARTER MILE OR LESS AT TIMES THIS AFTERNOON. WIND WILL ALSO
INCREASE RISK OF DOWNED TREES AND POWER LINES WITH FREEZING RAIN
ACCUMULATION.
I AM WORKING TO INCREASE SNOWFALL/SLEET AMOUNTS THIS MORNING AND
WILL CONTINUE TO UPDATE WEATHER TYPES. BOTTOM LINE IS THAT TRAVEL
WILL BE DIFFICULT... LAWN ORNAMENTS WILL BLOW AROUND... AND EXPECT
A VERY TREACHEROUS AFTERNOON COMMUTE.
&&
.PREV DISCUSSION... /ISSUED 347 AM CST MON DEC 28 2015/
TODAY AND TONIGHT...FORECAST CONFIDENCE MEDIUM.
MODELS ARE A LITTLE MORE IN LINE WITH THE SURFACE TRACK WITH THE GFS
STILL A LITTLE MORE SOUTH AND EAST. THE NAM IS SIMILAR TO THE ECMWF
BUT THE ECMWF IS A LITTLE FARTHER WEST LIKE THE HIGH RESOLUTION MESO
MODELS ESPECIALLY THE HRRR.
PRECIPITATION SHOULD REACH THE GROUND ALONG THE ILLINOIS BORDER AREA
AROUND 9AM CST AND REACH THE FOND DU LAC AND SHEBOYGAN AREAS JUST
AFTER 1 PM.
THIS WILL BE A VERY WET SYSTEM WITH PRECIPITABLE WATER VALUES UP
0.90 INCH BEING DRIVEN BY A 50 KNOT LOW LEVEL JET AHEAD OF A
COMPACT...OCCLUDING LOW PRESSURE SYSTEM. THERE WILL BE VERY STRONG
SYNOPTIC FORCING WITH THIS SYSTEM... WITH LAYER Q-VECTOR CONVERGENCE
OF 20 TO 50 UNITS AND VERY STRONG OMEGA DURING THE AFTERNOON
AND EARLY EVENING TIME PERIOD. WE ARE EXPECTING 0.50 TO 0.75 INCH OF
QPF/LIQUID PRECIP WITHIN 6 HOURS MONDAY AFTERNOON. THE BIG QUESTION
CONTINUES TO BE PRECIP TYPE.
ALTHOUGH THE GFS IS STILL COOLER WITH THE THERMAL PROFILES...MOST
MODELS ARE KEYING ON SLEET BEING THE BIGGEST FACTOR WITH THIS STORM
OVER THE FORECAST AREA...WITH FREEZING RAIN ALSO A CONCERN...EXCEPT
FAR EAST NEAR LAKE MICHIGAN WITH THE WARMER LAKE WATERS. FARTHER
WEST AND NORTH MORE OF A SNOW MIX IS EXPECTED. DUE TO EVAPORATIVE
COOLING MANY AREAS COULD SEE SOME SNOW INITIALLY.
AS THE LOW APPROACHES THE PRECIPITATION WILL TURN MORE RAIN IN THE
FAR SOUTHEAST...THEN A VARIETY OF DRIZZLE TYPES NEAR THE LOW. SOME
TRANSITION BACK TO LIGHT SNOW AS THE MID LEVEL LOW MOVES OVER.
STRONG EAST WINDS WILL FURTHER EXACERBATE TRAVEL CONDITIONS WITH
PERIODS OF WHITEOUT CONDITIONS IN THE MORE SNOW AREAS WEST OF
MADISON AND POTENTIAL IMPACTS FROM UP TO 0.10 TO 0.20 INCH OF
FREEZING RAIN. THUS A WINTER STORM WARNING CONTINUES FOR ALL OF
SOUTHERN AND EAST CENTRAL WISCONSIN.
GUSTY EAST WINDS WILL STEADILY INCREASE THIS MORNING AND BECOME VERY
STRONG BY MONDAY AFTERNOON. WIND GUSTS OF 40 TO 45 MPH
LIKELY...WITH SOME 50 MPH GUSTS POSSIBLE ESPECIALLY HIGH AREAS AND
NEAR LAKE MICHIGAN.
TUESDAY - CONFIDENCE...MEDIUM
LINGERING MID LEVEL CYCLONIC FLOW AS FIRST WAVE LIFTS NORTHEAST FROM
SRN WI AND SECONDARY WAVE SHIFTS SLOWLY NE FROM SRN MN VCNTY. BY
AFTERNOON MID LEVEL FLOW EXPECTED TO BR BROADLY ANTICYCLONIC.
SFC/850 CONVERGENCE PERSISTS IN THE MORNING AS LOW WEAKENS FURTHER
AND SHIFTS NE AWAY FROM LWR MI VCNTY. CONVERGENCE WEAKENS DURG THE
AFTN AND SHIFTS NORTH AWAY FROM SRN WI. MODELS ARE ALL SHOWING
SOME LIGHT QPF PERSISTING DURG THE MRNG HRS. OF PARTICULAR CONCERN
IS THE MID LEVEL DRYING WHICH RESULTS IN THE LOSS OF SATURATION
WITHIN THE DENDRIDIC GROWTH ZONE. SO EXPECT SOME FREEZING DRIZZLE
IN THIS SCENARIO. HIGHEST POPS WILL BE IN THE MORNING WITH A SHIFT
TOWARDS CONFINING POPS TO THE THE NORTHERN REACHES OF THE CWA FOR
THE AFTN HRS. LLVL RH PROGS KEEP THINGS MOIST SO STAYING
PESSIMISTIC WRT CLOUD COVER.
WEDNESDAY - CONFIDENCE...MEDIUM
ELONGATED VORT AXIS THEN PROGGD TO SHIFT NE FROM BASE OF WRN
TROUGH. NOT MUCH IN THE WAY OF A SFC REFLECTION TO THIS THOUGH A
SFC/850 TROUGH LIKELY TO AID IN SOME VERTICAL MOTION. QPF AMOUNTS
ARE LIGHT AND IN THIS CASE WE ARE SEEING ENOUGH SATURATION IN THAT
DENDRIDIC GROWTH ZONE TO GO WITH ALL SNOW ON THE PRECIP TYPE. SO
OVERALL LOOKS LIKE SOME AREAS SEE A 1/2 INCH OF SNOW.. THE GFS HAS
A SMIDGE HIGHER QPF THAT WOULD PERHAPS PUSH AN INCH BUT WILL GO
WITH MORE OF A CONSENSUS APPROACH WRT QPF AT THIS TIME.
THURSDAY THROUGH SUNDAY - CONFIDENCE...MEDIUM
OVERALL QUIET NW FLOW REGIME. GFS SUGGESTS SOME SHSN POTENTIAL
FOR THU BUT ECMWF IS DRY AND SUPERBLEND POPS LEAN THIS WAY. MAY
NEED A SMALL POP OR SOME FLURRIES EVENTUALLY BUT FOR NOW WILL KEEP
THINGS DRY. 925 TEMPS SUPPORT HIGHS MOSTLY IN THE 20S TO LOW 30S.
AVIATION/12Z TAFS/...
AVIATION/12Z TAFS/...THE EAST WINDS HAVE PUSHED AN MVFR CLOUD DECK
ACROSS MUCH OF SOUTHERN WISCONSIN DUE TO MOISTURE OFF LAKE MICHIGAN.
A STRONG LOW WILL MOVE ACROSS THE MID MISSISSIPPI VALLEY AND INTO
NORTHERN ILLINOIS THIS EVENING. PRECIPITATION WILL SPREAD NORTH.
INITIALLY DRY AIR WILL CAUSE VIRGA...BUT THE STRONG VERTICAL MOTION
WILL CAUSE PRECIPITATION TO REACH THE GROUND MID MORNING FAR SOUTH
AND TOWARDS NOON NEAR FOND DU LAC AND SHEBOYGAN. A WARM SURGE
AROUND 7 TO 9 THSD FT WILL CAUSE A MIX OF PRECIPITATION TO DEVELOP
WITH SLEET THE PREDOMINATE TYPE MOST AREAS. SOME FREEZING RAIN WILL
LATER THIS AFTERNOON INLAND AREAS. SNOW MAY FALL WITH THE ONSET AND
ALSO A MIX OF SNOW AND SLEET ESPECIALLY NORTH AND WEST OF
MADISON.
CIGS/VSBYS BECOMING IFR/LIFR THIS AFTERNOON AND EVENING.
NORTHEAST WINDS WILL VEER EAST...INCREASING TO 30 KNOTS MID-LATE
MORNING AND 40 KNOTS IN THE AFTERNOON...WITH 45 KNOT GUSTS IN THE
FAR EAST.
MARINE...WILL UPGRADE TO A STORM WARNING. HIGHEST STORM FORCE
GUSTS EXPECTED LATE AFTERNOON AND EARLY EVENING.
LATEST HIGH RESOLUTION HRRR EXPERIMENTAL SUPPORTS A HIGH-END GALE
WARNING...WITH STORM FORCE GUSTS LIKELY LATE AFTERNOON AND EARLY
EVENING. WILL OBVIOUSLY NEED A SMALL CRAFT ADVISORY FOR A TIME
OVERNIGHT MONDAY NIGHT AND TUESDAY AFTER THE GALE WARNING EXPIRES
AND THE LOW MOVES INTO SOUTHERN LAKE MICHIGAN DIMINISHING THE
WINDS.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...WINTER STORM WARNING UNTIL 6 AM CST TUESDAY FOR WIZ062>072.
LAKESHORE FLOOD ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR WIZ052-
060-066-071-072.
WINTER STORM WARNING UNTIL 6 AM CST TUESDAY FOR WIZ046-047-051-
052-056>060.
LM...STORM WARNING UNTIL 10 PM CST THIS EVENING FOR LMZ643>646.
&&
$$
UPDATE...MRC
TODAY/TONIGHT AND AVIATION/MARINE...HENTZ
TUESDAY THROUGH SUNDAY...COLLAR
AREA FORECAST DISCUSSION...UPDATED
NWS GREEN BAY WI
726 AM CST MON DEC 28 2015
NEW INFORMATION ADDED TO UPDATE SECTION
.UPDATE...
ISSUED AT 714 AM CST MON DEC 28 2015
THE LATEST SHORT-RANGE MODELS STARTING TO LOOK VERY OMINOUS FOR
E-C WI. IT/S LOOKING MORE AND MORE LIKE THE WARM AIR ALOFT WL
HAVE A HARD TIME MAKING INTO INTO E-C WI. THAT RAISES THE
POSSIBILITY THAT MOST OF THE PCPN WL BE SNOW. WITH IMPRESSIVE
RADAR RETURNS LINED UP FM NRN IL DOWN TO THE GULF...THAT COULD
REALLY DESTROY THE SNOWFALL FCST. COBB OUTPUT OFF THE LATEST RAP
AND HRRR HAVE 14.1 AND 5.9 INCHES OF SNOW IN GRB BY THE END OF THE
MODEL RUNS /HRRR COVERS LESS TIME AS MODEL RUN IS SHORTER/...WITH
THE EVENT STILL ONGOING. INTERESTINGLY...THEY BOTH ACTUALLY
INDICATE A BETTER SLEET POTENTIAL BACK IN CENTRAL WI. MY INITIAL
GUESS WOULD BE DRY AIR FEEDING IN FM RECEDING ANTICYCLONE IS
LEADING TO MORE COOLING IN THE E...KEEPING SOUNDINGS ALL SNOW
THERE.
DON/T WANT TO OVERREACT TO A COUPLE MODELS...BUT STARTING TO GET
VERY NERVOUS THAT GOING SNOW FCST FOR E-C WI WILL NOT HOLD. THE
MAGNITUDE OF THE COLD AIR IS ALSO REINFORCED BY THE FACT SNOW IS
STILL FALLING AT THE LEADING EDGE OF THE PCPN WAY DOWN IN NRN IL.
WL UPDATED PRODUCT SUITE TO PUSH SNOW TOTALS HIGHER. WL ALSO
MENTION NEAR BLIZZARD CONDITIONS IN E-C WI. TRAVEL LATE THIS
AFTN/EVENING IS LOOKING LIKE IT COULD BECOME A REAL NIGHTMARE.
&&
.SYNOPSIS...
ISSUED AT 602 AM CST MON DEC 28 2015
MAJOR WINTER STORM TO IMPACT THE AREA THIS AFTERNOON THROUGH
TUESDAY...A LITTLE MORE SNOW POSSIBLE MID-WEEK...THEN QUIETER FOR
THE REST OF THE PERIOD.
THE UPPER FLOW ACRS NOAM WL REMAIN SPLIT WITH 2 MORE ENERGETIC
SRN STREAM SYSTEMS TO CROSS THE REGION THE NEXT SEVERAL DAYS. THE
SPLIT WILL RE-STRUCTURE ITSELF LATE IN THE WEEK INTO THE UPCOMING
WEEKEND...WITH MORE OF THE WESTERLIES JOINING THE NRN STREAM...
AND THE SRN STREAM BECOMING WEAKER AND DISPLACED FARTHER SOUTH.
THAT WL USHER IN A MORE TRANQUIL WEATHER REGIME...WITH
TEMPERATURES DROPPING BACK CLOSER TO SEASONAL NORMALS THAN WE/VE
HAD IN A WHILE.
&&
.SHORT TERM...TODAY...TONIGHT...AND TUESDAY
ISSUED AT 602 AM CST MON DEC 28 2015
FCST FOCUS IS IN LINING UP THE DETAILS OF THE FCST FOR THE
INCOMING STORM SYSTEM. INTENSE UPR SYSTEM THAT TRACKED AMAZINGLY
FAR S ACRS TEXAS /AT LEAST FOR SOMETHING THAT/S GOING TO AFFECT
WI/ WL TURN NNE AND ABSOLUTELY RACE TO NRN IL BY LATE EVENING. STG
DEEP SLY FLOW ACRS THE ENTIRE GULF IS FEEDING ABUNDANT MOISTURE
NWD. PCPN SHIELD FM NRN IL DOWN TO THE GULF COAST WL CONT TO
SURGE NWD...THEN PIVOT ARND UPR SYSTEM AS IT ARRIVES IN THE AREA.
THE CHANGE IN THE GUIDANCE DURING THE PAST 24 HRS HAS BEEN TOWARD
A CONSENSUS TRACK OF THE UPR LOW ACRS SERN WI. SFC LOW WL BE
VERTICALLY STACKED UNDERNEATH BY THAT POINT. THAT/S PRETTY MUCH A
CLASSIC TRACK FOR HEAVY SNOW ACRS E-C WI. THERMAL FIELDS HAVE
FALLEN IN LINE. EACH SUCCESSIVE RUN OF THE WARM-OUTLIER NAM HAS
TRENDED COLDER. BUFR SOUNDINGS FM THE 06Z NAM WERE DOWN TO JUST A
SINGLE HR OF SLEET AT GRB /8 PM/. SO WITH MORE THE PCPN TO FALL AS
SNOW...UPPED TOTALS IN E-C WI FM PREV FCST. STILL A LITTLE
CONCERNED ABOUT PCPN TYPE IN THE SRN EDGE OF THE FCST AREA AND THE
LAKE MICHIGAN SHORELINE LOCATIONS. UPPED SNOWFALLS IN THESE AREAS
AS WELL...BUT FURTHER UPWARD ADJUSTMENT MAY BE NECESSARY IF THE
THE PROFILES CONT TO TREND COLDER. THE OTHER CHG WAS TO BACK DOWN
ON TOTALS A BIT IN VILAS COUNTY AS IT APPEARS THAT AREA WL BE ON
THE NW FRINGE OF THE HEAVY SNOWS.
STG ELY WINDS COMBINED WITH HEAVY SNOW WL MAKE A REAL MESS OF
TRAVEL LATE THIS AFTN INTO THIS EVENING. IT MIGHT HAVE BEEN IDEAL
TO HAVE HAD A START TIME OF THE WARNING AN HOUR OR TWO EARLIER
OVER THE FAR S...BUT NOT SURE THAT SMALL A CHANGE WOULD REALLY
HAVE MEANING AT THIS POINT. HAVE HIGHLIGHTED MY BEST GUESS AT
TIMING WITH SHARP POP GRADIENT IN THE GRIDS...AND IN AN SPS.
CONSIDERED THE POSSIBILITY OF GETTING BLIZZARD CONDITIONS IN E-C
WI FOR A TIME DURING THE LATE AFTN/EVENING. BUT HAVE SEEN SEVERAL
SITNS WITH TEMP PROFILES HAVING A DEEP NEAR FREEZING LAYER WHERE
SNOWFLAKES TEND TO STICK TOGETHER...SO VSBYS DON/T GO DOWN AS MUCH
AS NORMALLY ASSOCIATED WITH INCH AN HOUR SNOWS. GIVEN THE STRENGTH
OF THE DYNAMICS...A FEW RUMBLES OF THUNDER ALSO NOT OUT OF THE
QUESTION.
SNOWS WILL TAPER OFF FM S-N OVERNIGHT. SCT SHSN AND AREAS OF FZDZ
/DUE TO LOSS OF MID-LVL MOISTURE/ WL CONT INTO TUESDAY. IT/S
POSSIBLE A MESO-SCALE SNOW BAND COULD SET UP SOMEWHERE AND
PRODUCE ANOTHER 2-4 INCHES OF SNOW. DON/T KNOW FOR SURE IF/WHERE
THAT WOULD HAPPEN...BUT MOST CONCERNED ABOUT N-C WI DURING THE
AFTN AS DEFORMATION ZONE ON THE NW FLANK OF REMNANTS OF MID-LVL
CIRCULATION WL BE LINGERING IN THAT REGION.
.LONG TERM...TUESDAY NIGHT THROUGH SUNDAY
ISSUED AT 351 AM CST MON DEC 28 2015
ANOTHER UPPER LEVEL SYSTEM WILL CROSS THE AREA LATE TUESDAY NIGHT
INTO WEDNESDAY EVENING. MOISTURE WILL BE MUCH MORE LIMITED...BUT
THE SYSTEM COULD BRING SOME LIGHT SNOWS TO THE AREA.
COLDER AIR WILL SETTLE INTO THE AREA BEHIND THAT SYSTEM. HIGH
TEMPS WL BE NEAR OR MAYBE A LITTLE BELOW NORMAL. MIN TEMPS WILL
DEPEND ON CLOUD COVER. WITH A FRESH DEEP SNOWCOVER...ANY NIGHTS
WITH CLEAR SKIES AND LGTS WINDS COULD GET QUITE COLD.
&&
.AVIATION...FOR 12Z TAF ISSUANCE
ISSUED AT 602 AM CST MON DEC 28 2015
LAKE CLOUDS WL RESULT IN PRIMARILY MVFR CONDITIONS IN ADVANCE OF
THE APPROACHING SYSTEM TODAY. THEN LIFR CONDITIONS EXPECTED TO
DEVELOP NWD THIS AFTN AND EVENING AS THE MAIN SNOW BAND SHIFTS
THROUGH.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING FROM 3 PM THIS AFTERNOON TO 6 AM CST
TUESDAY FOR WIZ030-031-035>040-045-048>050.
WINTER STORM WARNING FROM 6 PM THIS EVENING TO 9 AM CST TUESDAY
FOR WIZ005-010>013-018>022-073-074.
&&
$$
UPDATE.........SKOWRONSKI
SYNOPSIS.......SKOWRONSKI
SHORT TERM.....SKOWRONSKI
LONG TERM......ECKBERG
AVIATION.......SKOWRONSKI
AREA FORECAST DISCUSSION...UPDATED
NWS RENO NV
1203 PM PST MON DEC 28 2015
.UPDATE...
UPDATED TO EXPIRE WINTER WEATHER ADVISORY ACROSS WESTERN NEVADA.
LIGHT SNOW CONTINUES TO FALL ACROSS MUCH OF WESTERN NEVADA, BUT
WITH ROAD TEMPS NEAR AND ABOVE FREEZING THEY ARE MAINLY WET RIGHT
NOW. THE SNOW WILL GRADUALLY DIMINISH DURING THE AFTERNOON ANY
ADDITIONAL IMPACT WILL BE SMALL. THERE REMAINS A THREAT OF WET
SURFACES REFREEZING THIS EVENING AS TEMPERATURES DROP WITH LOSS OF
HEATING, MOSTLY ON LESSER TRAVELED SIDE STREETS. WALLMANN
&&
.SYNOPSIS...
A COLD LOW PRESSURE SYSTEM WILL BRING SNOW SHOWERS TODAY. A
SECOND SYSTEM MAY PRODUCE LIGHT SNOW ON WEDNESDAY FOR AREAS NORTH
OF SUSANVILLE AND LOVELOCK. VALLEY INVERSIONS WILL DEVELOP LATE
THIS WEEK AS HIGH PRESSURE BUILDS OVERHEAD. SYSTEMS MAY BEGIN TO
UNDERCUT THE UPPER RIDGE EARLY NEXT WEEK FOR RENEWED CHANCES OF
PRECIPITATION.
&&
.PREVIOUS DISCUSSION... /ISSUED 300 AM PST MON DEC 28 2015/
SHORT TERM...
BEEFED UP WINDS FOR ALPINE/MONO RIDGES THIS MORNING AND AFTERNOON
WINDS FOR LAKE TAHOE AND PYRAMID LAKE, OTHERWISE MINIMAL CHANGES
TO THE SHORT TERM FORECAST.
LOW PRESSURE (EVIDENT IN WATER VAPOR SATELLITE) CENTERED OVER EXTREME
NORTHWEST CALIFORNIA WILL MOVE TO NEAR TAHOE BY LATE THIS MORNING.
LOOKING AT THE CURRENT INFRARED SATELLITE, THE INITIAL RAIN (BELOW
ABOUT 2000 FT) AND SNOW BAND OVER NORTHERN CALIFORNIA IS SLOWLY
ADVANCING INTO THE NORTHERN SIERRA AND GETTING ENHANCED BY DEFORMATION
JUST AHEAD OF THE UPPER LOW.
THIS MORNING, THE UPPER LOW CORE IS PROGGED TO DROP SOUTH TO NEAR
OR JUST WEST OF THE TAHOE CREST. THIS IS EXPECTED TO PUT WESTERN
NEVADA IN A FAVORABLE SPOT FOR DEFORMATION AND A PERIOD OF LIGHT
SNOW. IN FACT, THE LATEST RADAR SHOWS INDICATIONS OF LOWERING
CLOUD DECKS AND SOME VERY LIGHT SNOW BETWEEN RENO AND FALLON. WITH
THE SYSTEM BEING OF A SLIDER VARIETY, THE SIERRA IS NOT EXPECTED
TO GET MORE THAN A FEW INCHES OF SNOWFALL GIVEN THAT OROGRAPHIC
ENHANCEMENT WILL WANE THIS MORNING AS THE LOW DROPS OVERHEAD AND
LOW TO MID-LEVELS WINDS TURN NORTHERLY.
AS FAR AS TIMING FOR WIDESPREAD LIGHT SNOW BETWEEN RENO AND
LOVELOCK/FALLON, THE 09Z HRRR AND 06Z NAM INDICATE BETWEEN 4 AND 7 AM.
FROM A PATTERN RECOGNITION STANDPOINT, THIS MAKES SENSE AS WRAP-
AROUND/DEFORMATION SNOW WITH THIS TYPE OF SYSTEM OFTEN BREAKS OUT
AS THE LOW DROPS TO NEAR AND JUST SOUTH OF THE LATITUDE OF THE
AFFECTED AREA. WITH ROAD TEMPERATURES PLENTY COLD THIS MORNING,
WIDESPREAD LIGHT SNOW AND SNOW SHOWERS THIS MORNING COULD MAKE FOR
A SLICK COMMUTE FOR UNTREATED ROADS IN THE RENO-CARSON CITY AREA
THIS MORNING SO THE WINTER WEATHER ADVISORY WILL BE ALLOWED TO
CONTINUE.
AS FAR AS MINERAL AND SOUTHERN LYON COUNTIES, THE ADVISORY IS IN
MORE QUESTION AS SNOW DOES NOT LOOK TO START IN A WIDESPREAD
FASHION UNTIL AS LATE AS 8-10 AM. THE LATER IT STARTS THE LESS
LIKELY THAT THERE WILL BE SIGNIFICANT ROAD IMPACTS FOR LOWER
ELEVATION ROADS. STILL, HIGHER ROADS/PASSES SUCH AS SWEETWATER AND
ANCHORITE SUMMITS AND LUCKY BOY PASS COULD SEE SLICK CONDITIONS
BY LATE MORNING.
THIS AFTERNOON, THE FOCUS FOR SNOW SHOWERS SHIFTS INTO MONO AND
MINERAL COUNTIES AS THE DEFORMATION ZONE REACHES THAT AREA.
PRECIPITATION AMOUNTS SHOULD REMAIN LIGHT WITH UP TO A COUPLE
INCHES OF SNOWFALL POSSIBLE, BRINGING THE THREAT FOR ROAD CONTROLS
IN THE HIGHER ELEVATIONS.
TONIGHT THROUGH TUESDAY, THE SIERRA AND WESTERN NEVADA WILL BE
UNDER NORTHWEST FLOW ALOFT. THIS FLOW DOES NOT OFFER LONG PERIODS
OF CLEAR SKIES SO LOW TEMPERATURES WILL BE MODIFIED SOMEWHAT
(MAINLY TEENS TO AROUND 20 IN THE LOWER VALLEYS), ALTHOUGH CLOUDS
WILL HELP TO KEEP AFTERNOON TEMPERATURES CHILLY. LATE TUESDAY
NIGHT AND WEDNESDAY COULD BRING A WEAK SYSTEM INTO FAR NORTHERN
CALIFORNIA AND NEVADA FOR A CHANCE OF LIGHT SNOW SHOWERS,
GENERALLY NORTH OF SUSANVILLE AND GERLACH. SNYDER
LONG TERM...THURSDAY THROUGH SUNDAY...
MINOR CHANGES WERE MADE TO THE EXTENDED FORECAST TODAY TO LOWER
TEMPS A LITTLE MORE FOR MOST OF THE PERIOD...BUT OVERALL THE MODEL
SOLUTIONS REMAIN MUCH AS THEY WERE 12-24 HOURS AGO.
A BROAD RESIDUAL TROUGH OVER THE INTERMOUNTAIN WEST, ORIENTED
EAST TO WEST, IS IN PLACE AT THE START OF THE PERIOD. LOW LEVEL
NORTH TO NORTHEAST FLOW WILL KEEP TEMPS BELOW AVERAGE THROUGH AT
LEAST FRIDAY.
MODEL SOLUTIONS ARE A BIT AT ODDS WITH HOW TO EVOLVE THIS TROUGH AS
THE ECMWF STILL WANTS TO DEVELOP A CLOSED LOW ALONG THE OREGON
BORDER WHILE THE OPERATIONAL GFS DEVELOPS THIS CLOSED LOW OVER
EASTERN AND CENTRAL NEVADA AND DRIFTS IT TO THE WEST NORTHWEST
THROUGH SATURDAY. MOST OF THE GEFS ENSEMBLE MEMBERS HAVE SOLUTIONS
CLOSER TO THE OPERATIONAL GFS. NONE OF THE MODELS PRODUCE MUCH IN
THE WAY OF PRECIPITATION WITH THIS LOW. IT JUST LOCKS THE LOW TO MID
LEVEL EAST TO NORTHEAST FLOW INTO MOST OF THE AREA WITH BELOW NORMAL
TEMPERATURES. SO WE HAVE LEFT THE FORECAST DRY BUT LOWERED HIGH AND
LOW TEMPERATURES A FEW DEGREES FOR LATE THIS WEEK INTO THE WEEKEND.
LATE IN THE FORECAST PERIOD THE MODELS ARE TRYING TO LIFT THE LOW
OUT AND DEVELOP MORE OF A SOUTHWEST FLOW ALOFT. THIS IS IN RESPONSE
TO A BROAD TROUGH MOVING TOWARD THE CA COAST. THIS TROUGH IS SHOWN
CUTTING UNDER THE BROAD SCALE FLOW OVER THE REGION AND DRIVING A WET
SYSTEM INTO CENTRAL AND SOUTHERN CA BY EARLY NEXT WEEK. THE TRACK OF
THIS SYSTEM IS STILL VERY UNCERTAIN...BUT COULD BRING APPRECIABLE
SNOW TO THE CENTRAL AND SOUTHERN SIERRA. THE FORECAST FOR THIS
SYSTEM IS VERY LOW CONFIDENCE AT THIS TIME. 20
AVIATION...
AN ELONGATED AREA OF LOW PRESSURE IS MOVING INTO NORTHERN AND
CENTRAL CA AT THIS TIME. THIS LOW PRESSURE IS NOT VERY STRONG BUT IS
PRODUCING LIGHT PRECIPITATION FROM NORTHERN CA SOUTH INTO THE
CENTRAL VALLEY AND INTO THE NORTHERN SIERRA. LIGHT SNOW IS LIKELY
THROUGH THE MORNING HOURS THROUGH THE SIERRA. THIS COULD RESULT IN
PERIODS OF IFR CIGS/VSBYS THROUGH ABOUT 28/22UTC AND ACCUMULATIONS
UP TO 2 INCHES AT KTVL AND KTRK TODAY. MOUNTAIN OBSCURATIONS ARE
ALSO LIKELY.
EAST OF THE SIERRA AND ACROSS NORTHEAST CA AMOUNTS WILL BE LESS.
LIGHT SNOW IS POSSIBLE NORTH OF PORTOLA AND GERLACH EARLY THIS
MORNING MOVING SOUTH TO AROUND THE I-80 CORRIDOR IN WESTERN NEVADA
BY AROUND DAYBREAK. CURRENT INDICATIONS ARE SNOW WOULD DEVELOP SOUTH
OF HIGHWAY 50 AFTER ABOUT 6-8 AM THIS MORNING. OVERALL UP TO AN INCH
OF SNOW IS POSSIBLE AT KRNO AND KCXP. PERIODS OF MVFR ARE LIKELY
EAST OF THE SIERRA TODAY WITH BRIEF PERIODS OF IFR IN SNOW SHOWERS.
SURFACE WINDS SHOULD REMAIN FAIRLY LIGHT TODAY AND GUSTS OVER THE
SIERRA WILL BE AROUND 30-35 KTS.
DRIER WEATHER DEVELOPS FOR TUESDAY THEN ANOTHER FAST MOVING SYSTEM
BRINGS LIGHT SNOW TO AREAS NORTH OF A LINE FROM SUSANVILLE TO
LOVELOCK FROM LATE TUESDAY NIGHT INTO WEDNESDAY. 20
REV WATCHES/WARNINGS/ADVISORIES...
NV...WINTER WEATHER ADVISORY UNTIL NOON PST TODAY NVZ003-004.
WINTER WEATHER ADVISORY UNTIL NOON PST TODAY NVZ001.
CA...NONE.
$$
FOR MORE INFORMATION FROM THE NATIONAL WEATHER SERVICE VISIT...
&&
.REV WATCHES/WARNINGS/ADVISORIES...
NV...NONE.
CA...NONE.
&&
$$
FOR MORE INFORMATION FROM THE NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/RENO (ALL LOWER CASE)
SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NWS LOS ANGELES/OXNARD CA
855 AM PST MON DEC 28 2015
.SYNOPSIS...
A WEAK COLD FRONT WILL CROSS THE REGION TODAY WITH A CHANCE OF A
SHOWER OR TWO. THEN IT WILL BE CLEAR AND LOCALLY BREEZY FOR THE REST
OF THE WEEK.
&&
.SHORT TERM (TODAY-WED)...ANOTHER PATHETIC LITTLE COLD FRONT COMING
THROUGH THE AREA TODAY. IT JUST BARELY MANAGED TO SQUEEZE OUT A FEW
DROPS ALONG THE CENTRAL COAST BUT ONLY A COUPLE SPOTS WERE ABLE TO
MEASURE .01. WITH NORTHWEST FLOW DEVELOPING QUICKLY ACROSS THE AREA
TODAY I CAN`T IMAGINE SOUTHERN AREAS WILL HAVE ANY BETTER LUCK WITH
THE AMOUNTS, THOUGH CAN`T RULE OUT A SPRINKLE OR TWO. SO WHILE IT`S
PROBABLY CLOSER TO A 1 IN 20 CHANCE OF MEASURABLE RAIN AT ANY
GIVEN SPOT I`M GOING TO LEAVE IN THE LOW POPS WE HAVE GOING JUST SO
PEOPLE AREN`T CAUGHT OFF GUARD AND HEAD FOR THE HILLS IF A
HYDROMETEOR FALLS FROM THE SKY.
SKIES ARE ALREADY CLEARING NORTH OF PT CONCEPTION AND EXPECT MOST
AREAS WILL BE PARTLY CLOUDY BY LATER THIS MORNING OR EARLY
AFTERNOON. MOUNTAINS AND ESPECIALLY THE GRAPEVINE AREA WILL HOLD ON
TO THE CLOUDS A BIT LONGER. A CHILLY DAY AGAIN TODAY WITH SOME NORTH
WINDS PICKING UP (SEE BELOW). MAIN THING WITH THE AFTERNOON UPDATE
WILL BE TO ISSUE ANOTHER ROUND OF FROST/FREEZE PRODUCTS AS TEMPS
AGAIN DROP INTO THE 20S AND 30S ACROSS OUR COASTAL VALLEYS. THOUGH
WIND WILL MODERATE THE TEMPS IN SOME AREAS.
***FROM PREVIOUS DISCUSSION***
ANOTHER ROUND OF NORTH WINDS WILL BE USHERED IN BEHIND THE FRONT.
THESE WINDS WILL PILE UP SOME CLOUDS AND PRODUCE A CHANCE OF SNOW
SHOWERS AGAINST THE NORTH SLOPES. THE SNOW WILL NOT AMOUNT TO
MUCH AND SHOULD NOT POSE MUCH OF A THREAT TO TRAVELERS. LOW END WIND
ADVISORIES ARE IN EFFECT FROM 600 PM THIS EVENING TO NOON ON TUESDAY
FOR THE MOUNTAINS...THE WESTERN FOOTHILLS OF THE ANTELOPE VLY AND
THE SBA SOUTH COAST BELOW PASSES AND CANYONS. IT WILL STILL BE COLD
TONIGHT BUT JUST A LITTLE WARMER THAN THIS MORNING DUE TO THE EXTRA
WINDS.
COOL DRY NW FLOW SET UP OVER THE AREA FOR TUESDAY AND WEDNESDAY AND
THERE WILL NOT BE MUCH IN THE WAY OF WEATHER. SKIES WILL BE CLEAR.
MAX AND MIN TEMPS WILL REMAIN BLO NORMAL. THE ADVISORY LEVEL WINDS
WILL END BY NOON TUESDAY AND WEDNESDAY WILL ONLY HAVE WEAK SUB
ADVISORY CANYON WINDS IN THE MORNING.
.LONG TERM (THU-SUN)... THE UPPER PATTERN FOR XTND PERIOD IS
INTERESTING. ON THURSDAY A LONG WAVE TROF COVERS THE CONUS. LATER
THURSDAY ALL MDLS AGREE THAT SOME ENERGY WILL ENTER THE TROF FROM
CANADA WHICH WILL PUSH THE TROF MORE TO THE WEST. BY FRIDAY AN UPPER
WILL PINCH OFF FROM THE TROF (SOMEWHERE OVER SRN OR / NRN NV / OR
WRN UTAH THERE IS MUCH MDL DISAGREEMENT) FORMING A REX BLOCK INSIDE
A HUMONGOUS RIDGE THAT SPANS THE WEST COAST AND BRITISH COLUMBIA.
AFTER THAT THE MDLS ALL GO THEIR SEPARATE WAYS. A CLOSE LOOK AT SRN
CA HOWEVER SHOW THAT NO MATTER WHAT THE MDL SOLN IS THE WEATHER
SHOULD BE SIMILAR (THIS CANNOT BE SAID FOR ANYWHERE ELSE IN THE WEST
COAST)
THE UPPER PATTERN REALLY IS NOT WEATHER MAKER FOR THE XTND PERIOD.
THE BIG DEAL IS THE STRONG COLD SFC HIGH THAT WILL TAKE UP RESIDENCE
OVER THE GREAT BASIN. THERE WILL BE CONTINUOUS OFFSHORE FLOW THROUGH
THE PERIOD PEAKING EACH MORNING WITH THE DIURNAL CYCLE. THERE WILL
BE NORTHEAST CANYON WINDS FLIRTING WITH ADVISORY LEVELS EACH MORNING.
IT WILL BE DRY. DUE TO ALL OF THE COLD AIR POURING IN FROM THE
INTERIOR MAX TEMPS WILL NOT RISE MUCH DESPITE THE ADIABATIC WARMING
FROM THE NE FLOW. MAX TEMPS AT THE COAST MAY REACH NORMALS SATURDAY
BUT NO WHERE ELSE. SUNDAY WILL BE A LITTLE COOLER AS SOME CLOUDS
MOVE IN AHEAD OF APPROACHING SYSTEM.
ALL EYES ARE REALLY FOCUSED ON NEXT WEEK WHEN BOTH THE EC AND GFS
SHOW A SERIES OF STORMS LINING UP AND HEAD FOR SRN CA. BUT...BUT
WAIT THE DAY 8 FORECASTS HAVE BEEN EVEN LESS RELIABLE THAN USUAL
THIS WINTER SO ITS BEST TO STEP BACK AND WATCH TO SEE HOW THE MDLS
EVOLVE WITH THE FORECAST OF THESE SYSTEMS.
&&
.AVIATION...
28/1200Z
AT 12Z AT KLAX...THERE WAS NO MARINE LAYER OR INVERSION AT KLAX.
A FRONTAL SYSTEM WILL BRING A PERIOD OF MVFR CIGS TO SLO AND SBA
COUNTIES THIS MORNING THROUGH THIS AFTERNOON...THEN SKIES WILL
BECOME PARTLY CLOUDY. S OF PT CONCEPTION...CIGS ARE EXPECTED THIS
AFTERNOON AND EVENING...BUT THEY SHOULD GENERALLY BE 4000 FEET OR
GREATER. HOWEVER...LOCAL MVFR CIGS AND A SHOWER OR TWO ARE NOT
OUT OF THE QUESTION. GUSTY NW TO N WINDS WILL DEVELOP IN THE MTNS
AND ACROSS SRN SBA COUNTY LATE THIS AFTERNOON OR THIS EVENING
THEN PERSIST THROUGH TUE MORNING. THERE WILL BE LOCAL LLWS
AND MDT UDDF IN THESE AREAS.
KLAX...GOOD CONFIDENCE IN TAF. A 10 PERCENT CHC OF RAIN AND A 30
PERCENT CHC OF MVFR CIGS 17Z-22Z. THERE IS A 20 PERCENT CHC OF
NLY CROSS WINDS EXCEEDING 15 KNOTS BETWEEN 03Z AND 11Z.
KBUR...GOOD CONFIDENCE IN TAF. A 10 PERCENT CHC OF RAIN AND A 30
PERCENT CHC OF MVFR CIGS 17Z-22Z.
&&
.MARINE...
28/300 AM.
NORTHWEST WINDS WILL INCREASE THIS MORNING. SMALL CRAFT
ADVISORY CONDITIONS ARE LIKELY ACROSS THE ENTIRE COASTAL WATERS
BY MID TO LATE MORNING...EXCEPT POSSIBLY NOT UNTIL AFTERNOON
NEAR THE L.A. AND VTU COUNTY COAST. DECENT CONFIDENCE IN GALE
FOR WINDS ACROSS THE SOUTHERN TWO THIRDS OF THE OUTER WATERS.
THERE IS A 20 PERCENT CHANCE THAT WINDS WILL REMAIN AT SCA
LEVELS AND NOT RISE TO GALE FORCE IN THESE AREAS. HAZARDOUS SEAS
WILL CONT ACROSS THE OUTER WATERS THROUGH LATE TUE NIGHT.
&&
.LOX WATCHES/WARNINGS/ADVISORIES...
GALE WARNING (SEE LAXMWWLOX).
SMALL CRAFT ADVISORY (SEE LAXMWWLOX).
WIND ADVISORY (SEE LAXNPWLOX).
&&
$$
PUBLIC...MW/RORKE
AVIATION/MARINE...DB
SYNOPSIS...SETO
WWW.WEATHER.GOV/LOSANGELES
Area Forecast Discussion
National Weather Service Sacramento CA
844 AM PST MON DEC 28 2015
.Synopsis...
A cold weather system with low snow levels but limited moisture
will impact interior Northern California today. Another weak
system Tuesday night into Wednesday, otherwise mainly dry weather
for the week ahead.
&&
.Discussion...
Our current system is exiting the area and skies are clearing
rapidly behind it. As of now, it looks as though winds will be
light enough for some patchy fog in the Southern Sacramento Valley
tonight. We will be adding this to our forecast this afternoon.
.Previous Discussion...
Stronger short-wave associated with the digging upper trough
moving across NorCal early this morning presently resulting in a
band of showers extending from the northern Sierra southwestward
to south of the Bay Area. Amounts have been very light along this
band - only a few hundredths of an inch. Temperatures through the
valley mostly range from the mid 30s to lower 40s.
The main shower band is expected to move pretty quickly to the
south of the area this morning as the upper trough digs toward
SoCal limiting potential impacts. Only some lingering snow
showers are forecast along the northern Sierra Crest for the
afternoon. The area of showers presently over Cape Mendocino is
forecast by the HRRR to continue moving southward and weaken
offshore the Bay Area by midday.
Mainly dry weather with coolish temperatures is expected the
remainder of the year. However, another weak system is forecast
to drop down in northwesterly flow Tuesday night and Wednesday
bringing a few showers to the region, but it too will be
relatively moisture starved, so only light QPF expected.
&&
.EXTENDED DISCUSSION (Friday THROUGH Monday)
Dry weather for Friday and the weekend. Models depicting weak low
across West Coast but little impact expected on the region.
Temperatures will be be within a degree or two of normal. Next
chance for precipitation might arrive Monday with a pattern shift but
model differences are fairly large.
CEO
&&
.AVIATION...
Brief period of MVFR conditions to continue this morning as weak
weather system moves through with rain and snow showers. Snow
levels below 1000 feet north to 2000 feet across the northern
Sierra Nevada. Otherwise VFR conditions expected through the
evening with winds 10 kts or below for TAF sites. Light fog could
reduce visibilities to MVFR in Valley locations south of
Sacramento region tomorrow morning around 1200z.
NOO
&&
.STO Watches/Warnings/Advisories...
None.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
158 PM CST MON DEC 28 2015
.UPDATE...
1218 PM CST
QUICK ADDITIONAL UPDATE. MADE A FEW CALLS OUT TO EAST CENTRAL
ILLINOIS AND INDIANA COUNTIES SOUTH OF THE KANKAKEE RIVER AND
THERE WERE STILL SLICK SPOTS ON ROADS SHORTLY BEFORE 12PM CST.
THEREFORE...EXTENDED THE FREEZING RAIN ADVISORY FOR THESE COUNTIES
THROUGH 21Z. ALSO MADE TWEAKS TO HOURLY WEATHER GRIDS BASED OFF
OBSERVATIONAL TRENDS AND MESOANALYSIS TREND OF MAX WET BULB T
ALOFT...WHICH IS MODULATING P-TYPE. NORTH OF I-88/90 WAS MAINLY
SNOW AND SLEET BETWEEN 11AM AND 12PM AND NOW FINALLY STARTING TO
GET REPORTS OF MIXING WITH FREEZING RAIN. HAVE SLOWED TRANSITION
TO PLAIN RAIN AND ITS POSSIBLE THAT PREDOMINANT FREEZING RAIN
COULD HOLD ON UNTIL 1Z-2Z IN FAR NORTHERN IL...ESPECIALLY CLOSER
TO STATE LINE. WITH THIS BEING SAID...MAY NEED TO EXTEND WINTER
STORM WARNING END TIME FOR PART OF WARNING CURRENT SET TO EXPIRE
AT 6PM CST. MAY ALSO NEED TO EXTEND PART OF WARNING THAT ENDS AT
3PM. WILL MONITOR TRENDS OVER NEXT 1-2 HOURS BEFORE MAKING A
DECISION ON THIS.
FROM 955 AM CST
MONITORING OBSERVATIONAL TRENDS THIS MORNING AND FORECAST IS
LARGELY ON TRACK. HOWEVER...BASED ON REPORTS VIA EMERGENCY
MANAGERS AND SOCIAL MEDIA...AND EXPECTED NEAR TERM TEMPERATURE
TRENDS...WILL BE UPGRADING THE FREEZING RAIN ADVISORY TO A WINTER
STORM WARNING IN KANKAKEE AND LAKE AND PORTER COUNTIES THROUGH 3PM
CST. LATEST SPC/RAP MESOANALYSIS INDICATES ANTICIPATED WARMING OF
MAX WET BULB T ALOFT GRADUALLY LIFTING NORTHWARD...BUT THIS WILL
BE COUNTERACTED BE STRONG EASTERLY FLOW PULLING ON FEED OF LOWER
DEWPOINT AIR OVER NORTHERN INDIANA AND ASSOCIATED SURFACE
WETBULBING EFFECTS. WIDESPREAD 30-32 READINGS COULD REMAIN IN
PLACE THROUGH AT LEAST 18Z...AND EVEN AS LATE AS 20Z IF RECENT
RAP/HRRR RUNS ARE ON THE RIGHT TRACK. AS MENTIONED EARLIER...HAVE
RECEIVED MULTIPLE REPORTS OF VERY SLIPPERY ROADWAYS IN NW
INDIANA...AND ALSO SEVERAL REPORTS/PHOTOS ON SOCIAL MEDIA OF ICE
ACCUMULATION IN KANKAKEE COUNTY. WILL LEAVE FREEZING RAIN
ADVISORIES SOUTH OF THIS AREA IN PLACE WITH NO CHANGES...BUT WILL
BE MONITORING TEMP TRENDS CLOSELY.
FARTHER NORTH...MAINLY SLEET AND FREEZING RAIN HAS BEEN
OBSERVED...THOUGH RIGHT ALONG THE WISCONSIN STATE LINE SNOW HAS
BEEN PREDOMINANT PRECIPITATION TYPE. WOULD EXPECT TRANSITION TO
SLEET AND THEN FREEZING RAIN/SLEET TO COMMENCE...THOUGH WILL
CONTINUE TO MONITOR TRENDS. TOTAL SNOW/SLEET ACCUMS IN THE FAR
NORTH STILL APPEAR ON TRACK TO TOP OUT IN THE 1-2...LOCALLY 3 INCH
RANGE.
SURFACE LOW CURRENTLY OVER AR/MO BORDER LIFTING NORTH/NORTHEAST
WILL ONLY INCREASE MAGNITUDE OF PRESSURE FALLS AND ALREADY STRONG
EASTERLY WINDS GUSTING UP TO 45 MPH ALONG THE ILLINOIS SHORE. NO
CHANGES TO ONGOING WIND AND LAKESHORE FLOODING HEADLINES.
FINALLY...THERE HAVE BEEN SPORADIC CG LIGHTNING STRIKES ACROSS
CENTRAL IL AND INDIANA THIS MORNING IN STRONG WAA REGIME. AS DRY
SLOT OF IMPRESSIVE MID LATITUDE CYCLONE APPROACHES THIS
AFTERNOON...STEEPENING MID LEVEL LAPSE RATES WILL LIKELY YIELD AN
UPTICK IN OVERALL THUNDER COVERAGE. HIGH-RES GUIDANCE DEPICTS THIS
WELL AND THIS WILL BE SOMETHING TO WATCH FOR IN TERMS OF CAUSING
RAPID CHANGES IN P-TYPES...ESPECIALLY WITH NORTHWARD AND WESTWARD
EXTENT WHERE LOW LEVEL COLD WILL LINGER THE LONGEST.
OVERALL...STILL HAVE LOWER CONFIDENCE ON HOW LONG IT WILL TAKE FOR
NORTHWEST 1/3 OF CWA TO TRANSITION OVER TO PLAIN RAIN...LATEST MAY
BE 7-8PM.
CASTRO/RODRIGUEZ
&&
.SHORT TERM...
401 AM CST
THROUGH TUESDAY...
A MAJOR WIND AND ICE EVENT FOR A GOOD PORTION OF THE AREA...ALONG
WITH SOME OTHER ACCOMPANYING IMPACTS...IS BEGINNING TO UNFOLD INTO
THE REGION EARLY THIS MORNING. NO CHANGES PLANNED TO THE SPATIAL
EXTENT OF THE CURRENT MYRIAD OF HEADLINES...AS THEY COVER THIS
DYNAMIC SYSTEM WELL...WITH JUST SOME MINOR SHIFTS TO TIMING TO
COVER PRIME THREAT TIMES. WE ARE AT THE STAGE NOW OF INCORPORATING
OBSERVATIONAL TRENDS INTO THE GOING FORECAST WITH HOPEFULLY
ADJUSTMENTS MORE SO THAN MAJOR SHIFTS...AND THUS FAR THAT IS THE
CASE. HOWEVER BEING IN A TRANSITIONAL PRECIPITATION EVENT WHERE
SPECIFIC SURFACE AND ALOFT TEMPERATURES PLAY CRITICAL ROLES MAKES
THIS PARTICULARLY CHALLENGING.
THE MOST NOTEWORTHY CHANGES/OBSERVATIONS IN SUMMARY ARE THE OVERALL
FORECAST PRECIPITATION AMOUNTS HAVE BEEN INCREASED AREAWIDE LATE
MORNING THROUGH THE AFTERNOON AS IT IS MORE APPARENT CONVECTIVE
ELEMENTS AND SLANTWISE INSTABILITY WILL IMPINGE INTO THE AREA. THE
OVERLAP AREA OF THESE HEAVIER INTENSITY/AMOUNTS AND THE STILL COLD
ENOUGH FOR FREEZING RAIN APPEARS TO BE ALONG/NORTH OF INTERSTATE
80 AND ALONG AND WEST OF ILLINOIS 47...SO HAVE BUMPED UP FORECAST
ICE ACCUMULATIONS IN THESE AREAS AND PLACED HEAVY WORDING IN THE
FORECAST. HAVE ALSO ADDED ISOLATED/SCATTERED THUNDER...ALTHOUGH
THAT SHOULD BE MAINLY AFTER THE PEAK ICING TIME.
ALSO CONTINUED AN ADJUSTMENT OF A BIT SLOWER TEMPERATURE RECOVERY
IN THE IMMEDIATE LOW-LEVELS RESULTING IN LONGER SLEET DURATION
ALONG AND NORTH OF I-88...WITH THAT POTENTIALLY THE DOMINANT
PRECIPITATION TYPE MOST OF THE MORNING IN THAT REGION. HAVE UPPED
SLEET ACCUMULATION TO AROUND AN INCH THOUGH HIGHER TOTALS
CERTAINLY POSSIBLE DEPENDING ON RATE. WHILE IMPACTS DURING THE
MORNING MAY BE LESS IF THIS MAINLY SLEET/INTERMITTENT SNOW
MATERIALIZES...THE ICING POTENTIAL IN THE AFTERNOON WITH STRONG
WINDS STILL LOOKS ON TRACK.
A VERY POTENT SYSTEM IN ALMOST EVERY DEFINITION IS CENTERED OVER
THE ARKLATEX EARLY THIS MORNING...WHICH WILL HAVE A TRACK RECORD
WHEN IT IS FINISHED LATE TONIGHT WITH AFFECTING ALMOST EVERY
CENTRAL CONUS STATE WITH SOME FORM OF IMPACTING WEATHER. A 70
DEGREE TEMPERATURE DIFFERENCE FROM NORTHWEST IOWA TO NORTHERN
MISSISSIPPI EARLY THIS MORNING HIGHLIGHTS THE BAROCLINICITY THAT
THE WARM AND MOIST ADVECTION IS OVERRIDING INTO OUR AREA.
PRECIPITATION WITH THE LEADING EDGE OF THIS IN THE SOUTHERN CWA
HAS BEEN A LIGHT MIXED BAG THUS FAR. NEAR DAYBREAK INTENSITY LOOKS
TO UPTICK IN RESPONSE TO INCREASING DIFFLUENCE AND LOWER TO MID-
LEVEL F-GEN. THIS WILL CAUSE A PRONOUNCED WET-BULBING COOLING
EFFECT AS INHERENT DRY AIR BECOMES SATURATED WITHIN THE LOW-LEVEL
NORTHEAST FLOW. EARLY MORNING AMDAR DATA NEAR CHICAGO INDICATE A
WARM NOSE AROUND 2C ALOFT AND A LOW-LEVEL COLD NOSE AROUND -5C...
BOTH OF WHICH THE RAP SEEMS TO BE INITIALIZING WELL WITH OVER ITS
PAST FEW RUNS...LENDING SOME CONFIDENCE OF FINE TUNING THE
FORECAST TOWARD IT THIS MORNING. THE VERTICAL PROFILES AND
EXPECTED UPTICK IN PRECIP INTENSITY SHOULD CAUSE THE MAIN TYPE AT
FIRST TO BE ICE PELLETS OR EVEN SOME LIGHT SNOW /WHICH HAS BEEN
REPORTED/. BEING WITHIN THE LOW-LEVEL CONVEYOR BELT OF THIS MATURE
SYSTEM THIS MORNING...WITH 45 KT NORTHEAST 925MB FLOW PER
PROFILERS...THIS SEEMS TO SUPPORT THE TREND FOR P-TYPE TO WANT TO
REMAIN AS SLEET WITH OCCASIONAL SNOW IN FAR NORTHERN PARTS OF THE
CWA INTO LATE MORNING WITH MINOR ACCUMULATIONS. MORE IMPORTANTLY
FOR IMPACTS IT ALSO KEEPS THE FREEZING RAIN CORRIDOR IN PLACE TO
THE SOUTH OF THIS...THROUGH THE MORNING AND EVEN POTENTIALLY EARLY
AFTERNOON. TO HELP VISUALIZE...THIS IS ROUGHLY 30 MILES OR SO
NORTH OR SOUTH OF INTERSTATE 80.
THE AREAS IN THE SHADOW OF THE LAKE...INCLUDING CENTRAL AREAS OF
THE CHICAGO METRO...STILL LOOK LIKE THEY COULD STRUGGLE TO SEE
TEMPERATURES DROP MUCH DUE TO THE STRONG ADVECTION FROM THE
LAKE...SO ICING IS A LITTLE LESS OF A THREAT FOR THESE IMMEDIATE
NEARSHORE LOCATIONS...INCLUDING DOWNTOWN. HOWEVER WIND SPEEDS WILL
BE THE MAXIMUM...GUSTING TO IMPRESSIVE MAGNITUDES TO 50 TO 60 MPH
THIS AFTERNOON AND EARLY EVENING.
THE INGREDIENTS FOR THE WINDS TODAY AND INTO EARLY EVENING CONTINUE
TO JUST BE TRULY STRIKING. PRESSURE FALLS OF AROUND 15MB ARE
FORECAST BETWEEN 10AM AND 3PM OVER MUCH OF THE CWA THIS AFTERNOON.
HAVE CONTINUED WITH FORECAST HIGH END WIND GUSTS AND CORRELATED
DUAL IMPACT WITH ANY ICED LINES AND LIMBS. WIDESPREAD POWER
OUTAGES STILL LOOK POTENTIALLY REALIZED WHERE THE HEAVIER ICE
ACCUMULATIONS OCCUR.
AS THE STACKED SYSTEM CENTER AND ASSOCIATED DEEP TROPOSPHERIC FOLD
MOVES TOWARD THE AREA MID-AFTERNOON...THE WARM MOIST CONVEYOR
BELT NOSE PUSHES INTO THE AREA WITH SOME HEAVY PRECIPITATION AGAIN
LIKELY. ELEVATED INSTABILITY VALUES SUPPORT THUNDER INCLUSION. THE
LOW WILL PASS OVER WITH WINDS THEN EASING. FORCING LOOKS ENOUGH
STILL TO WARRANT SCATTERED RAIN SHOWERS ACROSS THE AREA AND
POSSIBLY EVEN SOME DRIZZLE. THE CHANCE FOR SOME OF THIS TO BE SNOW
SHOWERS INCREASES OVERNIGHT...ALTHOUGH THE INTENSITY SHOULD BE
LIGHT ENOUGH WITH MARGINAL SURFACE TEMPERATURES TO NOT REALLY HAVE
ANY ACCUMULATION. SOME OF THESE SHOWERS MAY LINGER INTO TUESDAY
MORNING...WITH WRAPAROUND COLD ADVECTION KEEPING TEMPERATURES
FROM RISING ANY AND HIGHS IN THE 30S.
MTF
&&
.LONG TERM...
204 AM CST
WEDNESDAY THROUGH SUNDAY...
THE MAIN FEATURE OF THE EXTENDED FORECAST PERIOD IS THE
ESTABLISHMENT OF AN EASTERN NORTH AMERICAN MEAN TROUGH...WITH
UPPER RIDGING BUILDING ACROSS THE NORTHWESTERN U.S. AND WESTERN
CANADA. THIS SETS THE STAGE FOR A PERIOD OF BELOW-AVERAGE COLD
THURSDAY THROUGH SUNDAY...THE FIRST MULTIPLE DAY STRETCH OF
BELOW AVERAGE TEMPERATURES FOR OUR AREA SINCE THE WEEK BEFORE
THANKSGIVING.
BY WEDNESDAY MORNING...THE OCCLUDED SURFACE LOW PRESSURE
ASSOCIATED WITH OUR NEAR TERM WINTER STORM WILL BE FILLING OVER
THE NORTHERN GREAT LAKES...WITH ITS TRAILING COLD FRONT EAST OF
THE FORECAST AREA. ANOTHER MID-LEVEL SHORT WAVE IS PROGGED TO
LIFT OUT OF THE LARGE WESTERN CONUS UPPER TROUGH DURING THE
MORNING...AND EVENTUALLY TAKING THE OLD SURFACE LOW OFF TO THE
NORTHEAST OF THE REGION. 00Z GFS/ECMWF AND GEM RUNS ARE ALL VERY
SIMILAR IN GENERATING AN AXIS OF LIGHT QPF BETWEEN 0.01-0.07"
ACROSS PARTS OF NORTH CENTRAL AND NORTHEAST ILLINOIS DURING THE
MORNING...MAINLY NORTHWEST OF THE I-55 CORRIDOR. USING A MODEL
BLEND QPF AND COBB OUTPUT SNOW/LIQUID RATIOS FROM ROUGHLY 11-13:1
ACROSS THE MAIN QPF AXIS DURING THE PERIOD...SUPPORTING A FEW
TENTHS OF AN INCH OF SNOW ACCUMULATION PERHAPS UP TO A HALF
INCH NORTHWEST OF THE CHICAGO AREA IN THE 12-18Z PERIOD. ONLY A
FEW FLURRIES PERHAPS LINGERING AT MIDDAY/EARLY AFTERNOON.
THE LONG WAVE UPPER TROUGH EVOLVES EASTWARD ACROSS CENTRAL NORTH
AMERICA WEDNESDAY NIGHT AND THURSDAY...EVENTUALLY BECOMING
ELONGATED IN A POSITIVE-TILT SOUTHWEST-NORTHEAST ORIENTATION BY
FRIDAY WITH THE TROUGH AXIS MOVING SOUTHEAST OF THE FORECAST
AREA. AT THE SURFACE...SURFACE LOW PRESSURE ASSOCIATED WITH
WEDNESDAYS DISTURBANCE PULLS AWAY TO THE EAST...WITH A BROAD
REGION OF COLDER WEST-NORTHEAST LOW LEVEL FLOW EAST OF STRONG
SURFACE HIGH PRESSURE DEVELOPING ACROSS THE NORTHERN AND
CENTRAL HIGH PLAINS. WHILE A FEW MINOR AMPLITUDE DISTURBANCES
APPEAR TO MOVE THROUGH THE FLOW ALOFT...LOW LEVELS ARE DOMINATED
BY COLDER...DRIER MODIFIED ARCTIC AIR AND LITTLE IN THE WAY OF
ORGANIZED PRECIP CHANCES ARE NOTED THROUGH THE WEEKEND. COLD
AIR...APPROACHING -10 TO -12 C AT 850 MB BY EARLY FRIDAY...
WILL LIKELY SUPPORT LAKE EFFECT SNOW SHOWERS DOWNWIND OF THE
LAKE ACROSS LOWER MICHIGAN. AS INDICATED ABOVE...THE PERIOD
FROM THURSDAY THROUGH SATURDAY LOOKS TO BE OUR FIRST MULTI-DAY
STRETCH OF BELOW AVERAGE TEMPS IN OVER A MONTH. MODEL LOW LEVEL
THERMAL PROGS AND GFS/ECMWF MOS NUMBERS DEPICT HIGHS IN THE 20S
THUR-FRI WITH LOWS IN THE TEENS AND EVEN A FEW SINGLE DIGITS
IN OUR TYPICALLY COLDEST SPOTS. AVERAGE TEMPS AROUND THE FIRST
OF THE YEAR ARE 30/14 AT ROCKFORD AND 31/17 FOR CHICAGO.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED Z...
* EAST-NORTHEAST WINDS GUSTING 35-40KT THIS AFTERNOON AND
EVENING.
* FZRA TRANSITIONING TO ICE PELLETS AND THEN RAIN.
* CIGS TURNING IFR THIS AFTERNOON.
* ISOLATED THUNDER CHANCE THIS AFTERNOON.
MM
//DISCUSSION...UPDATED 18Z...
AS LOW PRESSURE CONTINUES TO TRACK NORTHEAST TOWARD THE TAF
SITES...COLD AND DRY NORTHEAST SURFACE CONTINUE TO MAINTAIN
FREEZING TEMPERATURES. THIS TREND WILL KEEP FZRA IN THE FORECAST
FOR AN ADDITIONAL HOUR...TIL 21Z. AT THAT TIME WARMER TEMPERATURES
FROM THE SOUTH WILL MAKE IT TO CHICAGO AND TRANSITION P-TYPE TO
ALL RAIN. RADAR TRENDS CONTINUE TO SUPPORT THE MODERATE INTENSITY
FOR THE NEXT 1-2 HOURS...WITH LOWER CONFIDENCE AFTER THAT POINT.
UPSTREAM OBSERVATIONS AND MODEL GUIDANCE CONTINUE TO SUPPORT
LOWERING CEILINGS AS THE LOW APPROACHES. THIS WILL LEAD TO IFR
CONDITIONS WITHIN RAIN THROUGH THIS EVENING. THE TIGHT PRESSURE
GRADIENT AND PRESSURE FALLS WILL RELAX SOME AFTER 00Z AND MORE SO
AFTER 03Z...BUT UNTIL THE CENTER OF THE LOW PASSES...EXPECT GUSTS
NEAR THE 40KT MARK.
INTO TUESDAY...SOME WRAP-AROUND MOISTURE MAY KEEP ISOLATED RASN
MIX POSSIBLE IN THE MORNING HOURS...WITH FURTHER DRYING OCCURRING
TOWARDS THE AFTERNOON HOURS. A DECENT MID-LEVEL INVERSION TUESDAY
WILL KEEP LOW LEVEL MOISTURE INTACT AND KEEP MVFR CIGS IN PLACE.
PRESSURE RISES WILL THEN ALLOW WESTERLY WINDS TO GUST INTO THE
20KT RANGE TUESDAY.
MM
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE IN WIND TRENDS.
* HIGH CONFIDENCE IN FZRA TRANSITION TO PL AND RA...MEDIUM
CONFIDENCE IN TRANSITION TIMING.
* MEDIUM HIGH IN IFR CIGS...MEDIUM IN TIMING.
* MEDIUM IN TS THREAT...LOW IN OCCURRENCE AT ANY AIRPORT.
MM
//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...
TUESDAY NIGHT...VFR. SW WINDS.
WEDNESDAY...MVFR CIGS. CHANCE -SN OR -RASN EARLY WITH IFR
POSSIBLE. VFR/WX NIL LATE. SW WINDS.
THURSDAY...MVFR CIGS PSBL IN THE MORNING. W WINDS.
FRIDAY/SATURDAY...VFR/WX NIL. W WINDS.
SUNDAY...LAKE EFFECT SNOW SHOWERS PSBL MAINLY ALONG AND EAST OF
THE TERMINALS WITH MVFR CIGS. OTHERWISE VFR WITH NW WINDS.
KMD
&&
.MARINE...
416 AM CST
A STRONG PRESSURE GRADIENT BETWEEN ARCTIC HIGH PRESSURE IN
SOUTHERN ONTARIO AND DEEP LOW PRESSURE OVER THE ARKLATEX REGION
WILL STRENGTHEN TODAY AS THE LOW SHIFTS NORTHWARD THROUGH THE DAY
AND THE HIGH SHIFTS EASTWARD. GALE FORCE WINDS WILL INCREASE OVER
THE ENTIRE LAKE TODAY...WITH STORM FORCE WINDS EXPECTED FOR A
TIME THIS AFTERNOON AND EARLY EVENING ACROSS THE SOUTHERN HALF OF
THE LAKE.WITH A STRONG EAST FETCH...THESE WINDS LOOK TO AFFECT THE
ILLINOIS NEARSHORE AS WELL. THESE STRONG WINDS WILL RESULT IN
WAVES POSSIBLY REACHING NEAR 20 FT OVER THE SOUTH HALF OF THE
LAKE AND ILLINOIS NEARSHORE. THERE MAY BE A BRIEF PERIOD OF STORM
FORCE GUSTS THIS EVENING ACROSS THE NORTH...BUT HAVE HELD TO THE
GALE WARNING FOR THE NORTH HALF AS THE WINDOW APPEARS TO BE
SHORTER THAN FOR THE SOUTH HALF. THE LOW WILL PUSH NORTHEAST OVER
THE LAKE OVERNIGHT THEN NORTHEAST OF THE LAKE ON TUESDAY...AND
THIS WILL ALLOW WINDS AND WAVES TO SUBSIDE SIGNIFICANTLY AFTER
THIS POINT. MODERATE WESTERLY FLOW WILL CONTINUE OVER THE LAKE
FOR MUCH OF THE LATTER HALF OF THE WEEK.
KMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...LAKESHORE FLOOD WARNING...ILZ006-ILZ014 UNTIL MIDNIGHT TUESDAY.
HIGH WIND WARNING...ILZ006-ILZ014 UNTIL 7 PM MONDAY.
WINTER STORM WARNING...ILZ013-ILZ014-ILZ021-ILZ022-ILZ023 UNTIL
3 PM MONDAY.
WINTER STORM WARNING...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ019-ILZ020 UNTIL 6 PM MONDAY.
WIND ADVISORY...ILZ013-ILZ021-ILZ022-ILZ023-ILZ032-ILZ033-ILZ039
UNTIL 6 PM MONDAY.
FREEZING RAIN ADVISORY...ILZ032-ILZ033-ILZ039 UNTIL 3 PM MONDAY.
FLASH FLOOD WATCH...ILZ033-ILZ039 UNTIL 6 PM MONDAY.
IN...WIND ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL 6 PM
MONDAY.
WINTER STORM WARNING...INZ001-INZ002 UNTIL 3 PM MONDAY.
FLASH FLOOD WATCH...INZ010-INZ011-INZ019 UNTIL 6 PM MONDAY.
FREEZING RAIN ADVISORY...INZ010-INZ011-INZ019 UNTIL 3 PM MONDAY.
LM...STORM WARNING...ILLINOIS NEARSHORE WATERS UNTIL 9 PM MONDAY.
GALE WARNING...INDIANA NEARSHORE WATERS UNTIL 9 PM MONDAY.
STORM WARNING...LMZ777-LMZ779 UNTIL MIDNIGHT TUESDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1219 PM CST MON DEC 28 2015
.UPDATE...
1218 PM CST
QUICK ADDITIONAL UPDATE. MADE A FEW CALLS OUT TO EAST CENTRAL
ILLINOIS AND INDIANA COUNTIES SOUTH OF THE KANKAKEE RIVER AND
THERE WERE STILL SLICK SPOTS ON ROADS SHORTLY BEFORE 12PM CST.
THEREFORE...EXTENDED THE FREEZING RAIN ADVISORY FOR THESE COUNTIES
THROUGH 21Z. ALSO MADE TWEAKS TO HOURLY WEATHER GRIDS BASED OFF
OBSERVATIONAL TRENDS AND MESOANALYSIS TREND OF MAX WET BULB T
ALOFT...WHICH IS MODULATING P-TYPE. NORTH OF I-88/90 WAS MAINLY
SNOW AND SLEET BETWEEN 11AM AND 12PM AND NOW FINALLY STARTING TO
GET REPORTS OF MIXING WITH FREEZING RAIN. HAVE SLOWED TRANSITION
TO PLAIN RAIN AND ITS POSSIBLE THAT PREDOMINANT FREEZING RAIN
COULD HOLD ON UNTIL 1Z-2Z IN FAR NORTHERN IL...ESPECIALLY CLOSER
TO STATE LINE. WITH THIS BEING SAID...MAY NEED TO EXTEND WINTER
STORM WARNING END TIME FOR PART OF WARNING CURRENT SET TO EXPIRE
AT 6PM CST. MAY ALSO NEED TO EXTEND PART OF WARNING THAT ENDS AT
3PM. WILL MONITOR TRENDS OVER NEXT 1-2 HOURS BEFORE MAKING A
DECISION ON THIS.
FROM 955 AM CST
MONITORING OBSERVATIONAL TRENDS THIS MORNING AND FORECAST IS
LARGELY ON TRACK. HOWEVER...BASED ON REPORTS VIA EMERGENCY
MANAGERS AND SOCIAL MEDIA...AND EXPECTED NEAR TERM TEMPERATURE
TRENDS...WILL BE UPGRADING THE FREEZING RAIN ADVISORY TO A WINTER
STORM WARNING IN KANKAKEE AND LAKE AND PORTER COUNTIES THROUGH 3PM
CST. LATEST SPC/RAP MESOANALYSIS INDICATES ANTICIPATED WARMING OF
MAX WET BULB T ALOFT GRADUALLY LIFTING NORTHWARD...BUT THIS WILL
BE COUNTERACTED BE STRONG EASTERLY FLOW PULLING ON FEED OF LOWER
DEWPOINT AIR OVER NORTHERN INDIANA AND ASSOCIATED SURFACE
WETBULBING EFFECTS. WIDESPREAD 30-32 READINGS COULD REMAIN IN
PLACE THROUGH AT LEAST 18Z...AND EVEN AS LATE AS 20Z IF RECENT
RAP/HRRR RUNS ARE ON THE RIGHT TRACK. AS MENTIONED EARLIER...HAVE
RECEIVED MULTIPLE REPORTS OF VERY SLIPPERY ROADWAYS IN NW
INDIANA...AND ALSO SEVERAL REPORTS/PHOTOS ON SOCIAL MEDIA OF ICE
ACCUMULATION IN KANKAKEE COUNTY. WILL LEAVE FREEZING RAIN
ADVISORIES SOUTH OF THIS AREA IN PLACE WITH NO CHANGES...BUT WILL
BE MONITORING TEMP TRENDS CLOSELY.
FARTHER NORTH...MAINLY SLEET AND FREEZING RAIN HAS BEEN
OBSERVED...THOUGH RIGHT ALONG THE WISCONSIN STATE LINE SNOW HAS
BEEN PREDOMINANT PRECIPITATION TYPE. WOULD EXPECT TRANSITION TO
SLEET AND THEN FREEZING RAIN/SLEET TO COMMENCE...THOUGH WILL
CONTINUE TO MONITOR TRENDS. TOTAL SNOW/SLEET ACCUMS IN THE FAR
NORTH STILL APPEAR ON TRACK TO TOP OUT IN THE 1-2...LOCALLY 3 INCH
RANGE.
SURFACE LOW CURRENTLY OVER AR/MO BORDER LIFTING NORTH/NORTHEAST
WILL ONLY INCREASE MAGNITUDE OF PRESSURE FALLS AND ALREADY STRONG
EASTERLY WINDS GUSTING UP TO 45 MPH ALONG THE ILLINOIS SHORE. NO
CHANGES TO ONGOING WIND AND LAKESHORE FLOODING HEADLINES.
FINALLY...THERE HAVE BEEN SPORADIC CG LIGHTNING STRIKES ACROSS
CENTRAL IL AND INDIANA THIS MORNING IN STRONG WAA REGIME. AS DRY
SLOT OF IMPRESSIVE MID LATITUDE CYCLONE APPROACHES THIS
AFTERNOON...STEEPENING MID LEVEL LAPSE RATES WILL LIKELY YIELD AN
UPTICK IN OVERALL THUNDER COVERAGE. HIGH-RES GUIDANCE DEPICTS THIS
WELL AND THIS WILL BE SOMETHING TO WATCH FOR IN TERMS OF CAUSING
RAPID CHANGES IN P-TYPES...ESPECIALLY WITH NORTHWARD AND WESTWARD
EXTENT WHERE LOW LEVEL COLD WILL LINGER THE LONGEST.
OVERALL...STILL HAVE LOWER CONFIDENCE ON HOW LONG IT WILL TAKE FOR
NORTHWEST 1/3 OF CWA TO TRANSITION OVER TO PLAIN RAIN...LATEST MAY
BE 7-8PM.
CASTRO/RODRIGUEZ
&&
.SHORT TERM...
401 AM CST
THROUGH TUESDAY...
A MAJOR WIND AND ICE EVENT FOR A GOOD PORTION OF THE AREA...ALONG
WITH SOME OTHER ACCOMPANYING IMPACTS...IS BEGINNING TO UNFOLD INTO
THE REGION EARLY THIS MORNING. NO CHANGES PLANNED TO THE SPATIAL
EXTENT OF THE CURRENT MYRIAD OF HEADLINES...AS THEY COVER THIS
DYNAMIC SYSTEM WELL...WITH JUST SOME MINOR SHIFTS TO TIMING TO
COVER PRIME THREAT TIMES. WE ARE AT THE STAGE NOW OF INCORPORATING
OBSERVATIONAL TRENDS INTO THE GOING FORECAST WITH HOPEFULLY
ADJUSTMENTS MORE SO THAN MAJOR SHIFTS...AND THUS FAR THAT IS THE
CASE. HOWEVER BEING IN A TRANSITIONAL PRECIPITATION EVENT WHERE
SPECIFIC SURFACE AND ALOFT TEMPERATURES PLAY CRITICAL ROLES MAKES
THIS PARTICULARLY CHALLENGING.
THE MOST NOTEWORTHY CHANGES/OBSERVATIONS IN SUMMARY ARE THE OVERALL
FORECAST PRECIPITATION AMOUNTS HAVE BEEN INCREASED AREAWIDE LATE
MORNING THROUGH THE AFTERNOON AS IT IS MORE APPARENT CONVECTIVE
ELEMENTS AND SLANTWISE INSTABILITY WILL IMPINGE INTO THE AREA. THE
OVERLAP AREA OF THESE HEAVIER INTENSITY/AMOUNTS AND THE STILL COLD
ENOUGH FOR FREEZING RAIN APPEARS TO BE ALONG/NORTH OF INTERSTATE
80 AND ALONG AND WEST OF ILLINOIS 47...SO HAVE BUMPED UP FORECAST
ICE ACCUMULATIONS IN THESE AREAS AND PLACED HEAVY WORDING IN THE
FORECAST. HAVE ALSO ADDED ISOLATED/SCATTERED THUNDER...ALTHOUGH
THAT SHOULD BE MAINLY AFTER THE PEAK ICING TIME.
ALSO CONTINUED AN ADJUSTMENT OF A BIT SLOWER TEMPERATURE RECOVERY
IN THE IMMEDIATE LOW-LEVELS RESULTING IN LONGER SLEET DURATION
ALONG AND NORTH OF I-88...WITH THAT POTENTIALLY THE DOMINANT
PRECIPITATION TYPE MOST OF THE MORNING IN THAT REGION. HAVE UPPED
SLEET ACCUMULATION TO AROUND AN INCH THOUGH HIGHER TOTALS
CERTAINLY POSSIBLE DEPENDING ON RATE. WHILE IMPACTS DURING THE
MORNING MAY BE LESS IF THIS MAINLY SLEET/INTERMITTENT SNOW
MATERIALIZES...THE ICING POTENTIAL IN THE AFTERNOON WITH STRONG
WINDS STILL LOOKS ON TRACK.
A VERY POTENT SYSTEM IN ALMOST EVERY DEFINITION IS CENTERED OVER
THE ARKLATEX EARLY THIS MORNING...WHICH WILL HAVE A TRACK RECORD
WHEN IT IS FINISHED LATE TONIGHT WITH AFFECTING ALMOST EVERY
CENTRAL CONUS STATE WITH SOME FORM OF IMPACTING WEATHER. A 70
DEGREE TEMPERATURE DIFFERENCE FROM NORTHWEST IOWA TO NORTHERN
MISSISSIPPI EARLY THIS MORNING HIGHLIGHTS THE BAROCLINICITY THAT
THE WARM AND MOIST ADVECTION IS OVERRIDING INTO OUR AREA.
PRECIPITATION WITH THE LEADING EDGE OF THIS IN THE SOUTHERN CWA
HAS BEEN A LIGHT MIXED BAG THUS FAR. NEAR DAYBREAK INTENSITY LOOKS
TO UPTICK IN RESPONSE TO INCREASING DIFFLUENCE AND LOWER TO MID-
LEVEL F-GEN. THIS WILL CAUSE A PRONOUNCED WET-BULBING COOLING
EFFECT AS INHERENT DRY AIR BECOMES SATURATED WITHIN THE LOW-LEVEL
NORTHEAST FLOW. EARLY MORNING AMDAR DATA NEAR CHICAGO INDICATE A
WARM NOSE AROUND 2C ALOFT AND A LOW-LEVEL COLD NOSE AROUND -5C...
BOTH OF WHICH THE RAP SEEMS TO BE INITIALIZING WELL WITH OVER ITS
PAST FEW RUNS...LENDING SOME CONFIDENCE OF FINE TUNING THE
FORECAST TOWARD IT THIS MORNING. THE VERTICAL PROFILES AND
EXPECTED UPTICK IN PRECIP INTENSITY SHOULD CAUSE THE MAIN TYPE AT
FIRST TO BE ICE PELLETS OR EVEN SOME LIGHT SNOW /WHICH HAS BEEN
REPORTED/. BEING WITHIN THE LOW-LEVEL CONVEYOR BELT OF THIS MATURE
SYSTEM THIS MORNING...WITH 45 KT NORTHEAST 925MB FLOW PER
PROFILERS...THIS SEEMS TO SUPPORT THE TREND FOR P-TYPE TO WANT TO
REMAIN AS SLEET WITH OCCASIONAL SNOW IN FAR NORTHERN PARTS OF THE
CWA INTO LATE MORNING WITH MINOR ACCUMULATIONS. MORE IMPORTANTLY
FOR IMPACTS IT ALSO KEEPS THE FREEZING RAIN CORRIDOR IN PLACE TO
THE SOUTH OF THIS...THROUGH THE MORNING AND EVEN POTENTIALLY EARLY
AFTERNOON. TO HELP VISUALIZE...THIS IS ROUGHLY 30 MILES OR SO
NORTH OR SOUTH OF INTERSTATE 80.
THE AREAS IN THE SHADOW OF THE LAKE...INCLUDING CENTRAL AREAS OF
THE CHICAGO METRO...STILL LOOK LIKE THEY COULD STRUGGLE TO SEE
TEMPERATURES DROP MUCH DUE TO THE STRONG ADVECTION FROM THE
LAKE...SO ICING IS A LITTLE LESS OF A THREAT FOR THESE IMMEDIATE
NEARSHORE LOCATIONS...INCLUDING DOWNTOWN. HOWEVER WIND SPEEDS WILL
BE THE MAXIMUM...GUSTING TO IMPRESSIVE MAGNITUDES TO 50 TO 60 MPH
THIS AFTERNOON AND EARLY EVENING.
THE INGREDIENTS FOR THE WINDS TODAY AND INTO EARLY EVENING CONTINUE
TO JUST BE TRULY STRIKING. PRESSURE FALLS OF AROUND 15MB ARE
FORECAST BETWEEN 10AM AND 3PM OVER MUCH OF THE CWA THIS AFTERNOON.
HAVE CONTINUED WITH FORECAST HIGH END WIND GUSTS AND CORRELATED
DUAL IMPACT WITH ANY ICED LINES AND LIMBS. WIDESPREAD POWER
OUTAGES STILL LOOK POTENTIALLY REALIZED WHERE THE HEAVIER ICE
ACCUMULATIONS OCCUR.
AS THE STACKED SYSTEM CENTER AND ASSOCIATED DEEP TROPOSPHERIC FOLD
MOVES TOWARD THE AREA MID-AFTERNOON...THE WARM MOIST CONVEYOR
BELT NOSE PUSHES INTO THE AREA WITH SOME HEAVY PRECIPITATION AGAIN
LIKELY. ELEVATED INSTABILITY VALUES SUPPORT THUNDER INCLUSION. THE
LOW WILL PASS OVER WITH WINDS THEN EASING. FORCING LOOKS ENOUGH
STILL TO WARRANT SCATTERED RAIN SHOWERS ACROSS THE AREA AND
POSSIBLY EVEN SOME DRIZZLE. THE CHANCE FOR SOME OF THIS TO BE SNOW
SHOWERS INCREASES OVERNIGHT...ALTHOUGH THE INTENSITY SHOULD BE
LIGHT ENOUGH WITH MARGINAL SURFACE TEMPERATURES TO NOT REALLY HAVE
ANY ACCUMULATION. SOME OF THESE SHOWERS MAY LINGER INTO TUESDAY
MORNING...WITH WRAPAROUND COLD ADVECTION KEEPING TEMPERATURES
FROM RISING ANY AND HIGHS IN THE 30S.
MTF
&&
.LONG TERM...
204 AM CST
WEDNESDAY THROUGH SUNDAY...
THE MAIN FEATURE OF THE EXTENDED FORECAST PERIOD IS THE
ESTABLISHMENT OF AN EASTERN NORTH AMERICAN MEAN TROUGH...WITH
UPPER RIDGING BUILDING ACROSS THE NORTHWESTERN U.S. AND WESTERN
CANADA. THIS SETS THE STAGE FOR A PERIOD OF BELOW-AVERAGE COLD
THURSDAY THROUGH SUNDAY...THE FIRST MULTIPLE DAY STRETCH OF
BELOW AVERAGE TEMPERATURES FOR OUR AREA SINCE THE WEEK BEFORE
THANKSGIVING.
BY WEDNESDAY MORNING...THE OCCLUDED SURFACE LOW PRESSURE
ASSOCIATED WITH OUR NEAR TERM WINTER STORM WILL BE FILLING OVER
THE NORTHERN GREAT LAKES...WITH ITS TRAILING COLD FRONT EAST OF
THE FORECAST AREA. ANOTHER MID-LEVEL SHORT WAVE IS PROGGED TO
LIFT OUT OF THE LARGE WESTERN CONUS UPPER TROUGH DURING THE
MORNING...AND EVENTUALLY TAKING THE OLD SURFACE LOW OFF TO THE
NORTHEAST OF THE REGION. 00Z GFS/ECMWF AND GEM RUNS ARE ALL VERY
SIMILAR IN GENERATING AN AXIS OF LIGHT QPF BETWEEN 0.01-0.07"
ACROSS PARTS OF NORTH CENTRAL AND NORTHEAST ILLINOIS DURING THE
MORNING...MAINLY NORTHWEST OF THE I-55 CORRIDOR. USING A MODEL
BLEND QPF AND COBB OUTPUT SNOW/LIQUID RATIOS FROM ROUGHLY 11-13:1
ACROSS THE MAIN QPF AXIS DURING THE PERIOD...SUPPORTING A FEW
TENTHS OF AN INCH OF SNOW ACCUMULATION PERHAPS UP TO A HALF
INCH NORTHWEST OF THE CHICAGO AREA IN THE 12-18Z PERIOD. ONLY A
FEW FLURRIES PERHAPS LINGERING AT MIDDAY/EARLY AFTERNOON.
THE LONG WAVE UPPER TROUGH EVOLVES EASTWARD ACROSS CENTRAL NORTH
AMERICA WEDNESDAY NIGHT AND THURSDAY...EVENTUALLY BECOMING
ELONGATED IN A POSITIVE-TILT SOUTHWEST-NORTHEAST ORIENTATION BY
FRIDAY WITH THE TROUGH AXIS MOVING SOUTHEAST OF THE FORECAST
AREA. AT THE SURFACE...SURFACE LOW PRESSURE ASSOCIATED WITH
WEDNESDAYS DISTURBANCE PULLS AWAY TO THE EAST...WITH A BROAD
REGION OF COLDER WEST-NORTHEAST LOW LEVEL FLOW EAST OF STRONG
SURFACE HIGH PRESSURE DEVELOPING ACROSS THE NORTHERN AND
CENTRAL HIGH PLAINS. WHILE A FEW MINOR AMPLITUDE DISTURBANCES
APPEAR TO MOVE THROUGH THE FLOW ALOFT...LOW LEVELS ARE DOMINATED
BY COLDER...DRIER MODIFIED ARCTIC AIR AND LITTLE IN THE WAY OF
ORGANIZED PRECIP CHANCES ARE NOTED THROUGH THE WEEKEND. COLD
AIR...APPROACHING -10 TO -12 C AT 850 MB BY EARLY FRIDAY...
WILL LIKELY SUPPORT LAKE EFFECT SNOW SHOWERS DOWNWIND OF THE
LAKE ACROSS LOWER MICHIGAN. AS INDICATED ABOVE...THE PERIOD
FROM THURSDAY THROUGH SATURDAY LOOKS TO BE OUR FIRST MULTI-DAY
STRETCH OF BELOW AVERAGE TEMPS IN OVER A MONTH. MODEL LOW LEVEL
THERMAL PROGS AND GFS/ECMWF MOS NUMBERS DEPICT HIGHS IN THE 20S
THUR-FRI WITH LOWS IN THE TEENS AND EVEN A FEW SINGLE DIGITS
IN OUR TYPICALLY COLDEST SPOTS. AVERAGE TEMPS AROUND THE FIRST
OF THE YEAR ARE 30/14 AT ROCKFORD AND 31/17 FOR CHICAGO.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* EAST-NORTHEAST WINDS GUSTING 35-42 KT THIS AFTERNOON AND
EVENING.
* FZRA ONGOING UNTIL TURNING ALL RAIN AT 21Z.
* MVFR CIGS TURNING IFR THIS AFTERNOON WITH IFR VSBYS ONGOING.
* ISOLATED THUNDER CHANCE THIS AFTERNOON.
MM
//DISCUSSION...UPDATED 18Z...
AS LOW PRESSURE CONTINUES TO TRACK NORTHEAST TOWARD THE TAF
SITES...COLD AND DRY NORTHEAST SURFACE CONTINUE TO MAINTAIN
FREEZING TEMPERATURES. THIS TREND WILL KEEP FZRA IN THE FORECAST
FOR AN ADDITIONAL HOUR...TIL 21Z. AT THAT TIME WARMER TEMPERATURES
FROM THE SOUTH WILL MAKE IT TO CHICAGO AND TRANSITION P-TYPE TO
ALL RAIN. RADAR TRENDS CONTINUE TO SUPPORT THE MODERATE INTENSITY
FOR THE NEXT 1-2 HOURS...WITH LOWER CONFIDENCE AFTER THAT POINT.
UPSTREAM OBSERVATIONS AND MODEL GUIDANCE CONTINUE TO SUPPORT
LOWERING CEILINGS AS THE LOW APPROACHES. THIS WILL LEAD TO IFR
CONDITIONS WITHIN RAIN THROUGH THIS EVENING. THE TIGHT PRESSURE
GRADIENT AND PRESSURE FALLS WILL RELAX SOME AFTER 00Z AND MORE SO
AFTER 03Z...BUT UNTIL THE CENTER OF THE LOW PASSES...EXPECT GUSTS
NEAR THE 40KT MARK.
INTO TUESDAY...SOME WRAP-AROUND MOISTURE MAY KEEP ISOLATED RASN
MIX POSSIBLE IN THE MORNING HOURS...WITH FURTHER DRYING OCCURRING
TOWARDS THE AFTERNOON HOURS. A DECENT MID-LEVEL INVERSION TUESDAY
WILL KEEP LOW LEVEL MOISTURE INTACT AND KEEP MVFR CIGS IN PLACE.
PRESSURE RISES WILL THEN ALLOW WESTERLY WINDS TO GUST INTO THE
20KT RANGE TUESDAY.
MM
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH CONFIDENCE IN WIND TRENDS.
* HIGH CONFIDENCE IN FZRA ONGOING WITH MEDIUM CONFIDENCE IN
TRANSITION TIMING.
* MEDIUM HIGH IN MVFR/IFR CIG/VIS VALUES...MEDIUM IN TIMING.
* MEDIUM IN TS THREAT...LOW IN OCCURRENCE AT ANY AIRPORT.
MM
//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...
TUESDAY NIGHT...VFR. SW WINDS.
WEDNESDAY...MVFR CIGS. CHANCE -SN OR -RASN EARLY WITH IFR
POSSIBLE. VFR/WX NIL LATE. SW WINDS.
THURSDAY...MVFR CIGS PSBL IN THE MORNING. W WINDS.
FRIDAY/SATURDAY...VFR/WX NIL. W WINDS.
SUNDAY...LAKE EFFECT SNOW SHOWERS PSBL MAINLY ALONG AND EAST OF
THE TERMINALS WITH MVFR CIGS. OTHERWISE VFR WITH NW WINDS.
KMD
&&
.MARINE...
416 AM CST
A STRONG PRESSURE GRADIENT BETWEEN ARCTIC HIGH PRESSURE IN
SOUTHERN ONTARIO AND DEEP LOW PRESSURE OVER THE ARKLATEX REGION
WILL STRENGTHEN TODAY AS THE LOW SHIFTS NORTHWARD THROUGH THE DAY
AND THE HIGH SHIFTS EASTWARD. GALE FORCE WINDS WILL INCREASE OVER
THE ENTIRE LAKE TODAY...WITH STORM FORCE WINDS EXPECTED FOR A
TIME THIS AFTERNOON AND EARLY EVENING ACROSS THE SOUTHERN HALF OF
THE LAKE.WITH A STRONG EAST FETCH...THESE WINDS LOOK TO AFFECT THE
ILLINOIS NEARSHORE AS WELL. THESE STRONG WINDS WILL RESULT IN
WAVES POSSIBLY REACHING NEAR 20 FT OVER THE SOUTH HALF OF THE
LAKE AND ILLINOIS NEARSHORE. THERE MAY BE A BRIEF PERIOD OF STORM
FORCE GUSTS THIS EVENING ACROSS THE NORTH...BUT HAVE HELD TO THE
GALE WARNING FOR THE NORTH HALF AS THE WINDOW APPEARS TO BE
SHORTER THAN FOR THE SOUTH HALF. THE LOW WILL PUSH NORTHEAST OVER
THE LAKE OVERNIGHT THEN NORTHEAST OF THE LAKE ON TUESDAY...AND
THIS WILL ALLOW WINDS AND WAVES TO SUBSIDE SIGNIFICANTLY AFTER
THIS POINT. MODERATE WESTERLY FLOW WILL CONTINUE OVER THE LAKE
FOR MUCH OF THE LATTER HALF OF THE WEEK.
KMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...LAKESHORE FLOOD WARNING...ILZ006-ILZ014 UNTIL MIDNIGHT TUESDAY.
WINTER STORM WARNING...ILZ013-ILZ014-ILZ021-ILZ022-ILZ023 UNTIL
3 PM MONDAY.
HIGH WIND WARNING...ILZ006-ILZ014 UNTIL 7 PM MONDAY.
WINTER STORM WARNING...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ019-ILZ020 UNTIL 6 PM MONDAY.
WIND ADVISORY...ILZ013-ILZ021-ILZ022-ILZ023-ILZ032-ILZ033-ILZ039
UNTIL 6 PM MONDAY.
FREEZING RAIN ADVISORY...ILZ032-ILZ033-ILZ039 UNTIL 3 PM MONDAY.
FLASH FLOOD WATCH...ILZ033-ILZ039 UNTIL 6 PM MONDAY.
IN...WIND ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL 6 PM
MONDAY.
WINTER STORM WARNING...INZ001-INZ002 UNTIL 3 PM MONDAY.
FLASH FLOOD WATCH...INZ010-INZ011-INZ019 UNTIL 6 PM MONDAY.
FREEZING RAIN ADVISORY...INZ010-INZ011-INZ019 UNTIL 3 PM MONDAY.
LM...STORM WARNING...ILLINOIS NEARSHORE WATERS UNTIL 9 PM MONDAY.
GALE WARNING...INDIANA NEARSHORE WATERS UNTIL 9 PM MONDAY.
STORM WARNING...LMZ777-LMZ779 UNTIL MIDNIGHT TUESDAY.
&&
$$
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AREA FORECAST DISCUSSION
National Weather Service Lincoln IL
1203 PM CST MON DEC 28 2015
.UPDATE...
ISSUED AT 1037 AM CST MON DEC 28 2015
Intensifying low pressure system currently along the
Arkansas/Missouri border, feeding plenty of moisture into the
region and perpetuating a lot of rainfall. Flooding of area rivers
ongoing and forecast, as well as intense winds out of the ENE,
gusting to near 50 mph at times. Freezing temps across the
northern tier of the state resulting in some ice accumulations,
although accumulation totals for ice over ILX counties remains
relatively light. Glazing and a tenth or so has been reported in
Knox, Woodford, and McLean counties. Going forecast is doing well
with some chance for fzra across the north, mixed in with mostly
rain through noon, and dwindling chances for fzra as the day
progresses. At this point, updates are not anticipated, but will
have to watch the temps in the extreme north for lingering near
the freezing mark, and adjust the precip types accordingly.
&&
.SHORT TERM...(Today)
ISSUED AT 343 AM CST MON DEC 28 2015
Rain has overspread the entire forecast area early this morning.
Galesburg temperature has dropped to 32, so some freezing rain
occurring there. Sleet may be mixing with rain north of a line from
Canton to Bloomington, but no confirmation is apparent in the web-
cameras that are available. Bloomington`s observation has carried
`unknown precipitation` for several hours already this morning with
air temps down to 33, so some sleet possibly occurring there.
The 00z NAM came in with warmer surface temps than previous model
runs, but the RAP and GFS keep a colder airmass across our northern
counties through the morning, supporting the winter weather scenario
in our headline products. Even the NAM still supports some freezing
rain with a mix of sleet this morning north of Peoria. We may see
slightly less ice than a quarter inch across the winter storm
warning area, but the impacts from any amount of ice could be large
due to the strong winds blowing the trees and power lines around
with any amount of ice. We will be keeping the headlines going
without any changes this morning. Winter storm warning for freezing
rain and sleet from Peoria and north until 3 pm looks fine, with a
freezing rain advisory from Fulton to McLean counties until noon
looking ok too.
The track of the surface low from south to north up the Mississippi
River Valley supports some thunder potential in our eastern and
southern counties through the day, with locally heavy rain still
possible. It also supports a surge of warm air into our entire
forecast area this afternoon, helping to shut down any additional
wintry precipitation. Impacts from any ice accumulation could last
after surface temperatures climb above freezing, due to strong winds
affecting icy trees and power lines.
A dry slot is forecast to progress from south to north through
Illinois this afternoon, so we diminished precip chances
accordingly. Areas north of I-74 should see precip linger until
evening.
.LONG TERM...(Tonight through Sunday)
ISSUED AT 343 AM CST MON DEC 28 2015
Strong surface low pressure of 997 mb over southeast OK to lift ne
into west central IL early this evening and lift across nw IL during
this evening. Low pressure will then weaken to 1002 mb as it lifts
into west central lower MI by 12Z/6 am Tue. Rain will diminish
quickly from sw to ne during this evening, with highest pops north
of I-74 early this evening, and just 20-30% chances of light
precipitation lingering overnight from I-74 northeast. Enough cold
air present to give a chance of light snow too over the IL river
valley tonight but little or no accumulations expected nw of the IL
river. Winds will drop off below wind advisory criteria by 6 pm and
become sw 15-25 mph by overnight. Went a few degrees cooler for lows
tonight ranging from near 30F far western CWA to the mid to upper
30s from I-57 east, with mildest readings near the Wabash river.
Breezy sw winds and clouds continue to linger over central IL on Tue
in wake of strong storm system pulling ne across Lake Huron, but
should be dry. Temperatures not expected to climb but a few degrees
on Tue with highs in the low to mid 30s west of I-57 and upper
30s/lower 40s east of I-57. Dry conditions continue on Tue night as
sw winds diminish. An approaching short wave from the Pacific states
to keep clouds around, with light snow chances just west of IL
overnight Tue night. Lows Tue night range from mid 20s over IL river
valley to lower 30s from I-70 southeast.
A large short wave lifts ne across IL and into lower MI during Wed
but has limited moisture over IL so will continue small chances (20-
30%) of light precipitation, mainly light snow central IL and chance
of light rain/snow in eastern/se IL. A fair amount of clouds again
on Wed with highs ranging from lower 30s over IL river valley to
around 40F in southeast IL.
Extended forecast models continue to show a large upper level trof
dominating the northeast half of the country during the 2nd half of
the week. Also large Canadian high pressure over the Rockies and
ridging into the southern plains to keep a cooler nw flow over IL
from Thu into New Years weekend. Temperatures averaging a bit below
normal for a change especially Thu/Fri when highs as cold as mid to
upper 20s in central IL and lows in the teens. Brunt of light snow
chances stays ne of central IL over the Great Lakes region late this
work week but could see more clouds linger still on Thu especially
in ne CWA, before mostly sunny skies eventually arrives Fri into the
weekend.
&&
.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
ISSUED AT 1150 AM CST MON DEC 28 2015
Ongoing precip and fzra in PIA and BMI. Temps hovering near
freezing through the early afternoon resulting in a mix of fzra
and ra, accumulating on some elevated sfcs, with the ground level
mostly wet. NE winds gusting in excess of 40kts for all terminals
through the afternoon. Cigs btwn 700 and 1200 ft, vis 1 to 5 and
variable. For the most part, IFR. LIFR/IFR conditions through
much of the evening hours and some minor improvement to low MVFR
after 04z-06z. Winds varying in direction through the overnight
coming around to more westerly after 06z and remaining gusty
through tomorrow morning.
&&
.ILX Watches/Warnings/Advisories...
Flash Flood Watch until 6 PM CST this evening for ILZ044>046-049-
050-052>057-061>063-066>068-071>073.
Wind Advisory until 6 PM CST this evening for ILZ027>031-036>038-
040>057-061.
Winter Storm Warning until 3 PM CST this afternoon for
ILZ027>031-038.
Flash Flood Watch through this evening for ILZ051.
Freezing Rain Advisory until 3 PM CST this afternoon for ILZ037.
&&
$$
UPDATE...HJS
SHORT TERM...Shimon
LONG TERM...07
AVIATION...HJS
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1152 AM CST MON DEC 28 2015
.UPDATE...
955 AM CST
MONITORING OBSERVATIONAL TRENDS THIS MORNING AND FORECAST IS
LARGELY ON TRACK. HOWEVER...BASED ON REPORTS VIA EMERGENCY
MANAGERS AND SOCIAL MEDIA...AND EXPECTED NEAR TERM TEMPERATURE
TRENDS...WILL BE UPGRADING THE FREEZING RAIN ADVISORY TO A WINTER
STORM WARNING IN KANKAKEE AND LAKE AND PORTER COUNTIES THROUGH 3PM
CST. LATEST SPC/RAP MESOANALYSIS INDICATES ANTICIPATED WARMING OF
MAX WET BULB T ALOFT GRADUALLY LIFTING NORTHWARD...BUT THIS WILL
BE COUNTERACTED BE STRONG EASTERLY FLOW PULLING ON FEED OF LOWER
DEWPOINT AIR OVER NORTHERN INDIANA AND ASSOCIATED SURFACE
WETBULBING EFFECTS. WIDESPREAD 30-32 READINGS COULD REMAIN IN
PLACE THROUGH AT LEAST 18Z...AND EVEN AS LATE AS 20Z IF RECENT
RAP/HRRR RUNS ARE ON THE RIGHT TRACK. AS MENTIONED EARLIER...HAVE
RECEIVED MULTIPLE REPORTS OF VERY SLIPPERY ROADWAYS IN NW
INDIANA...AND ALSO SEVERAL REPORTS/PHOTOS ON SOCIAL MEDIA OF ICE
ACCUMULATION IN KANKAKEE COUNTY. WILL LEAVE FREEZING RAIN
ADVISORIES SOUTH OF THIS AREA IN PLACE WITH NO CHANGES...BUT WILL
BE MONITORING TEMP TRENDS CLOSELY.
FARTHER NORTH...MAINLY SLEET AND FREEZING RAIN HAS BEEN
OBSERVED...THOUGH RIGHT ALONG THE WISCONSIN STATE LINE SNOW HAS
BEEN PREDOMINANT PRECIPITATION TYPE. WOULD EXPECT TRANSITION TO
SLEET AND THEN FREEZING RAIN/SLEET TO COMMENCE...THOUGH WILL
CONTINUE TO MONITOR TRENDS. TOTAL SNOW/SLEET ACCUMS IN THE FAR
NORTH STILL APPEAR ON TRACK TO TOP OUT IN THE 1-2...LOCALLY 3 INCH
RANGE.
SURFACE LOW CURRENTLY OVER AR/MO BORDER LIFTING NORTH/NORTHEAST
WILL ONLY INCREASE MAGNITUDE OF PRESSURE FALLS AND ALREADY STRONG
EASTERLY WINDS GUSTING UP TO 45 MPH ALONG THE ILLINOIS SHORE. NO
CHANGES TO ONGOING WIND AND LAKESHORE FLOODING HEADLINES.
FINALLY...THERE HAVE BEEN SPORADIC CG LIGHTNING STRIKES ACROSS
CENTRAL IL AND INDIANA THIS MORNING IN STRONG WAA REGIME. AS DRY
SLOT OF IMPRESSIVE MID LATITUDE CYCLONE APPROACHES THIS
AFTERNOON...STEEPENING MID LEVEL LAPSE RATES WILL LIKELY YIELD AN
UPTICK IN OVERALL THUNDER COVERAGE. HIGH-RES GUIDANCE DEPICTS THIS
WELL AND THIS WILL BE SOMETHING TO WATCH FOR IN TERMS OF CAUSING
RAPID CHANGES IN P-TYPES...ESPECIALLY WITH NORTHWARD AND WESTWARD
EXTENT WHERE LOW LEVEL COLD WILL LINGER THE LONGEST.
OVERALL...STILL HAVE LOWER CONFIDENCE ON HOW LONG IT WILL TAKE FOR
NORTHWEST 1/3 OF CWA TO TRANSITION OVER TO PLAIN RAIN...LATEST MAY
BE 7-8PM.
CASTRO/RODRIGUEZ
&&
.SHORT TERM...
401 AM CST
THROUGH TUESDAY...
A MAJOR WIND AND ICE EVENT FOR A GOOD PORTION OF THE AREA...ALONG
WITH SOME OTHER ACCOMPANYING IMPACTS...IS BEGINNING TO UNFOLD INTO
THE REGION EARLY THIS MORNING. NO CHANGES PLANNED TO THE SPATIAL
EXTENT OF THE CURRENT MYRIAD OF HEADLINES...AS THEY COVER THIS
DYNAMIC SYSTEM WELL...WITH JUST SOME MINOR SHIFTS TO TIMING TO
COVER PRIME THREAT TIMES. WE ARE AT THE STAGE NOW OF INCORPORATING
OBSERVATIONAL TRENDS INTO THE GOING FORECAST WITH HOPEFULLY
ADJUSTMENTS MORE SO THAN MAJOR SHIFTS...AND THUS FAR THAT IS THE
CASE. HOWEVER BEING IN A TRANSITIONAL PRECIPITATION EVENT WHERE
SPECIFIC SURFACE AND ALOFT TEMPERATURES PLAY CRITICAL ROLES MAKES
THIS PARTICULARLY CHALLENGING.
THE MOST NOTEWORTHY CHANGES/OBSERVATIONS IN SUMMARY ARE THE OVERALL
FORECAST PRECIPITATION AMOUNTS HAVE BEEN INCREASED AREAWIDE LATE
MORNING THROUGH THE AFTERNOON AS IT IS MORE APPARENT CONVECTIVE
ELEMENTS AND SLANTWISE INSTABILITY WILL IMPINGE INTO THE AREA. THE
OVERLAP AREA OF THESE HEAVIER INTENSITY/AMOUNTS AND THE STILL COLD
ENOUGH FOR FREEZING RAIN APPEARS TO BE ALONG/NORTH OF INTERSTATE
80 AND ALONG AND WEST OF ILLINOIS 47...SO HAVE BUMPED UP FORECAST
ICE ACCUMULATIONS IN THESE AREAS AND PLACED HEAVY WORDING IN THE
FORECAST. HAVE ALSO ADDED ISOLATED/SCATTERED THUNDER...ALTHOUGH
THAT SHOULD BE MAINLY AFTER THE PEAK ICING TIME.
ALSO CONTINUED AN ADJUSTMENT OF A BIT SLOWER TEMPERATURE RECOVERY
IN THE IMMEDIATE LOW-LEVELS RESULTING IN LONGER SLEET DURATION
ALONG AND NORTH OF I-88...WITH THAT POTENTIALLY THE DOMINANT
PRECIPITATION TYPE MOST OF THE MORNING IN THAT REGION. HAVE UPPED
SLEET ACCUMULATION TO AROUND AN INCH THOUGH HIGHER TOTALS
CERTAINLY POSSIBLE DEPENDING ON RATE. WHILE IMPACTS DURING THE
MORNING MAY BE LESS IF THIS MAINLY SLEET/INTERMITTENT SNOW
MATERIALIZES...THE ICING POTENTIAL IN THE AFTERNOON WITH STRONG
WINDS STILL LOOKS ON TRACK.
A VERY POTENT SYSTEM IN ALMOST EVERY DEFINITION IS CENTERED OVER
THE ARKLATEX EARLY THIS MORNING...WHICH WILL HAVE A TRACK RECORD
WHEN IT IS FINISHED LATE TONIGHT WITH AFFECTING ALMOST EVERY
CENTRAL CONUS STATE WITH SOME FORM OF IMPACTING WEATHER. A 70
DEGREE TEMPERATURE DIFFERENCE FROM NORTHWEST IOWA TO NORTHERN
MISSISSIPPI EARLY THIS MORNING HIGHLIGHTS THE BAROCLINICITY THAT
THE WARM AND MOIST ADVECTION IS OVERRIDING INTO OUR AREA.
PRECIPITATION WITH THE LEADING EDGE OF THIS IN THE SOUTHERN CWA
HAS BEEN A LIGHT MIXED BAG THUS FAR. NEAR DAYBREAK INTENSITY LOOKS
TO UPTICK IN RESPONSE TO INCREASING DIFFLUENCE AND LOWER TO MID-
LEVEL F-GEN. THIS WILL CAUSE A PRONOUNCED WET-BULBING COOLING
EFFECT AS INHERENT DRY AIR BECOMES SATURATED WITHIN THE LOW-LEVEL
NORTHEAST FLOW. EARLY MORNING AMDAR DATA NEAR CHICAGO INDICATE A
WARM NOSE AROUND 2C ALOFT AND A LOW-LEVEL COLD NOSE AROUND -5C...
BOTH OF WHICH THE RAP SEEMS TO BE INITIALIZING WELL WITH OVER ITS
PAST FEW RUNS...LENDING SOME CONFIDENCE OF FINE TUNING THE
FORECAST TOWARD IT THIS MORNING. THE VERTICAL PROFILES AND
EXPECTED UPTICK IN PRECIP INTENSITY SHOULD CAUSE THE MAIN TYPE AT
FIRST TO BE ICE PELLETS OR EVEN SOME LIGHT SNOW /WHICH HAS BEEN
REPORTED/. BEING WITHIN THE LOW-LEVEL CONVEYOR BELT OF THIS MATURE
SYSTEM THIS MORNING...WITH 45 KT NORTHEAST 925MB FLOW PER
PROFILERS...THIS SEEMS TO SUPPORT THE TREND FOR P-TYPE TO WANT TO
REMAIN AS SLEET WITH OCCASIONAL SNOW IN FAR NORTHERN PARTS OF THE
CWA INTO LATE MORNING WITH MINOR ACCUMULATIONS. MORE IMPORTANTLY
FOR IMPACTS IT ALSO KEEPS THE FREEZING RAIN CORRIDOR IN PLACE TO
THE SOUTH OF THIS...THROUGH THE MORNING AND EVEN POTENTIALLY EARLY
AFTERNOON. TO HELP VISUALIZE...THIS IS ROUGHLY 30 MILES OR SO
NORTH OR SOUTH OF INTERSTATE 80.
THE AREAS IN THE SHADOW OF THE LAKE...INCLUDING CENTRAL AREAS OF
THE CHICAGO METRO...STILL LOOK LIKE THEY COULD STRUGGLE TO SEE
TEMPERATURES DROP MUCH DUE TO THE STRONG ADVECTION FROM THE
LAKE...SO ICING IS A LITTLE LESS OF A THREAT FOR THESE IMMEDIATE
NEARSHORE LOCATIONS...INCLUDING DOWNTOWN. HOWEVER WIND SPEEDS WILL
BE THE MAXIMUM...GUSTING TO IMPRESSIVE MAGNITUDES TO 50 TO 60 MPH
THIS AFTERNOON AND EARLY EVENING.
THE INGREDIENTS FOR THE WINDS TODAY AND INTO EARLY EVENING CONTINUE
TO JUST BE TRULY STRIKING. PRESSURE FALLS OF AROUND 15MB ARE
FORECAST BETWEEN 10AM AND 3PM OVER MUCH OF THE CWA THIS AFTERNOON.
HAVE CONTINUED WITH FORECAST HIGH END WIND GUSTS AND CORRELATED
DUAL IMPACT WITH ANY ICED LINES AND LIMBS. WIDESPREAD POWER
OUTAGES STILL LOOK POTENTIALLY REALIZED WHERE THE HEAVIER ICE
ACCUMULATIONS OCCUR.
AS THE STACKED SYSTEM CENTER AND ASSOCIATED DEEP TROPOSPHERIC FOLD
MOVES TOWARD THE AREA MID-AFTERNOON...THE WARM MOIST CONVEYOR
BELT NOSE PUSHES INTO THE AREA WITH SOME HEAVY PRECIPITATION AGAIN
LIKELY. ELEVATED INSTABILITY VALUES SUPPORT THUNDER INCLUSION. THE
LOW WILL PASS OVER WITH WINDS THEN EASING. FORCING LOOKS ENOUGH
STILL TO WARRANT SCATTERED RAIN SHOWERS ACROSS THE AREA AND
POSSIBLY EVEN SOME DRIZZLE. THE CHANCE FOR SOME OF THIS TO BE SNOW
SHOWERS INCREASES OVERNIGHT...ALTHOUGH THE INTENSITY SHOULD BE
LIGHT ENOUGH WITH MARGINAL SURFACE TEMPERATURES TO NOT REALLY HAVE
ANY ACCUMULATION. SOME OF THESE SHOWERS MAY LINGER INTO TUESDAY
MORNING...WITH WRAPAROUND COLD ADVECTION KEEPING TEMPERATURES
FROM RISING ANY AND HIGHS IN THE 30S.
MTF
&&
.LONG TERM...
204 AM CST
WEDNESDAY THROUGH SUNDAY...
THE MAIN FEATURE OF THE EXTENDED FORECAST PERIOD IS THE
ESTABLISHMENT OF AN EASTERN NORTH AMERICAN MEAN TROUGH...WITH
UPPER RIDGING BUILDING ACROSS THE NORTHWESTERN U.S. AND WESTERN
CANADA. THIS SETS THE STAGE FOR A PERIOD OF BELOW-AVERAGE COLD
THURSDAY THROUGH SUNDAY...THE FIRST MULTIPLE DAY STRETCH OF
BELOW AVERAGE TEMPERATURES FOR OUR AREA SINCE THE WEEK BEFORE
THANKSGIVING.
BY WEDNESDAY MORNING...THE OCCLUDED SURFACE LOW PRESSURE
ASSOCIATED WITH OUR NEAR TERM WINTER STORM WILL BE FILLING OVER
THE NORTHERN GREAT LAKES...WITH ITS TRAILING COLD FRONT EAST OF
THE FORECAST AREA. ANOTHER MID-LEVEL SHORT WAVE IS PROGGED TO
LIFT OUT OF THE LARGE WESTERN CONUS UPPER TROUGH DURING THE
MORNING...AND EVENTUALLY TAKING THE OLD SURFACE LOW OFF TO THE
NORTHEAST OF THE REGION. 00Z GFS/ECMWF AND GEM RUNS ARE ALL VERY
SIMILAR IN GENERATING AN AXIS OF LIGHT QPF BETWEEN 0.01-0.07"
ACROSS PARTS OF NORTH CENTRAL AND NORTHEAST ILLINOIS DURING THE
MORNING...MAINLY NORTHWEST OF THE I-55 CORRIDOR. USING A MODEL
BLEND QPF AND COBB OUTPUT SNOW/LIQUID RATIOS FROM ROUGHLY 11-13:1
ACROSS THE MAIN QPF AXIS DURING THE PERIOD...SUPPORTING A FEW
TENTHS OF AN INCH OF SNOW ACCUMULATION PERHAPS UP TO A HALF
INCH NORTHWEST OF THE CHICAGO AREA IN THE 12-18Z PERIOD. ONLY A
FEW FLURRIES PERHAPS LINGERING AT MIDDAY/EARLY AFTERNOON.
THE LONG WAVE UPPER TROUGH EVOLVES EASTWARD ACROSS CENTRAL NORTH
AMERICA WEDNESDAY NIGHT AND THURSDAY...EVENTUALLY BECOMING
ELONGATED IN A POSITIVE-TILT SOUTHWEST-NORTHEAST ORIENTATION BY
FRIDAY WITH THE TROUGH AXIS MOVING SOUTHEAST OF THE FORECAST
AREA. AT THE SURFACE...SURFACE LOW PRESSURE ASSOCIATED WITH
WEDNESDAYS DISTURBANCE PULLS AWAY TO THE EAST...WITH A BROAD
REGION OF COLDER WEST-NORTHEAST LOW LEVEL FLOW EAST OF STRONG
SURFACE HIGH PRESSURE DEVELOPING ACROSS THE NORTHERN AND
CENTRAL HIGH PLAINS. WHILE A FEW MINOR AMPLITUDE DISTURBANCES
APPEAR TO MOVE THROUGH THE FLOW ALOFT...LOW LEVELS ARE DOMINATED
BY COLDER...DRIER MODIFIED ARCTIC AIR AND LITTLE IN THE WAY OF
ORGANIZED PRECIP CHANCES ARE NOTED THROUGH THE WEEKEND. COLD
AIR...APPROACHING -10 TO -12 C AT 850 MB BY EARLY FRIDAY...
WILL LIKELY SUPPORT LAKE EFFECT SNOW SHOWERS DOWNWIND OF THE
LAKE ACROSS LOWER MICHIGAN. AS INDICATED ABOVE...THE PERIOD
FROM THURSDAY THROUGH SATURDAY LOOKS TO BE OUR FIRST MULTI-DAY
STRETCH OF BELOW AVERAGE TEMPS IN OVER A MONTH. MODEL LOW LEVEL
THERMAL PROGS AND GFS/ECMWF MOS NUMBERS DEPICT HIGHS IN THE 20S
THUR-FRI WITH LOWS IN THE TEENS AND EVEN A FEW SINGLE DIGITS
IN OUR TYPICALLY COLDEST SPOTS. AVERAGE TEMPS AROUND THE FIRST
OF THE YEAR ARE 30/14 AT ROCKFORD AND 31/17 FOR CHICAGO.
RATZER
&&
.HYDROLOGY...
A POWERFUL STORM SYSTEM WILL DRAW COPIOUS AMOUNTS OF MOISTURE
NORTHWARD ON MONDAY. SOME OF THE PRECIPITATION WILL FALL AS SLEET
AND FREEZING RAIN. TOTAL FORECAST LIQUID EQUIVALENT AMOUNTS ARE IN
THE 1 TO 1.5 INCH RANGE ACROSS NORTHERN AND CENTRAL ILLINOIS AND
NORTHWEST INDIANA. WITH SUCH ANOMALOUSLY HIGH MOISTURE
LEVELS...LOCALLY HIGHER TOTALS ARE PROBABLE. 24-HOUR RAIN AMOUNTS
FROM SATURDAY INTO SUNDAY MORNING WERE UP TO 2-3 INCHES SOUTH OF
THE KANKAKEE RIVER. THIS RAIN HAS ALREADY RESULTED IN RISES ON
RIVERS AND STREAMS IN THIS AREA. THE ADDITIONAL RAIN ON MONDAY
WILL EXACERBATE AND PROLONG ONGOING RISES. FOR AREAS FARTHER
NORTH...RIVER AND STREAM LEVELS ARE ALREADY RUNNING ABOVE
NORMAL...AND THE HEAVY FORECAST PRECIPITATION WILL RESULT IN
RENEWED RISES.
RC
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* EAST-NORTHEAST WINDS GUSTING 35-42 KT THIS AFTERNOON AND
EVENING.
* FZRA ONGOING UNTIL TURNING ALL RAIN AT 21Z.
* MVFR CIGS TURNING IFR THIS AFTERNOON WITH IFR VSBYS ONGOING.
* ISOLATED THUNDER CHANCE THIS AFTERNOON.
MM
//DISCUSSION...UPDATED 18Z...
AS LOW PRESSURE CONTINUES TO TRACK NORTHEAST TOWARD THE TAF
SITES...COLD AND DRY NORTHEAST SURFACE CONTINUE TO MAINTAIN
FREEZING TEMPERATURES. THIS TREND WILL KEEP FZRA IN THE FORECAST
FOR AN ADDITIONAL HOUR...TIL 21Z. AT THAT TIME WARMER TEMPERATURES
FROM THE SOUTH WILL MAKE IT TO CHICAGO AND TRANSITION P-TYPE TO
ALL RAIN. RADAR TRENDS CONTINUE TO SUPPORT THE MODERATE INTENSITY
FOR THE NEXT 1-2 HOURS...WITH LOWER CONFIDENCE AFTER THAT POINT.
UPSTREAM OBSERVATIONS AND MODEL GUIDANCE CONTINUE TO SUPPORT
LOWERING CEILINGS AS THE LOW APPROACHES. THIS WILL LEAD TO IFR
CONDITIONS WITHIN RAIN THROUGH THIS EVENING. THE TIGHT PRESSURE
GRADIENT AND PRESSURE FALLS WILL RELAX SOME AFTER 00Z AND MORE SO
AFTER 03Z...BUT UNTIL THE CENTER OF THE LOW PASSES...EXPECT GUSTS
NEAR THE 40KT MARK.
INTO TUESDAY...SOME WRAP-AROUND MOISTURE MAY KEEP ISOLATED RASN
MIX POSSIBLE IN THE MORNING HOURS...WITH FURTHER DRYING OCCURRING
TOWARDS THE AFTERNOON HOURS. A DECENT MID-LEVEL INVERSION TUESDAY
WILL KEEP LOW LEVEL MOISTURE INTACT AND KEEP MVFR CIGS IN PLACE.
PRESSURE RISES WILL THEN ALLOW WESTERLY WINDS TO GUST INTO THE
20KT RANGE TUESDAY.
MM
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH CONFIDENCE IN WIND TRENDS.
* HIGH CONFIDENCE IN FZRA ONGOING WITH MEDIUM CONFIDENCE IN
TRANSITION TIMING.
* MEDIUM HIGH IN MVFR/IFR CIG/VIS VALUES...MEDIUM IN TIMING.
* MEDIUM IN TS THREAT...LOW IN OCCURRENCE AT ANY AIRPORT.
MM
//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...
TUESDAY NIGHT...VFR. SW WINDS.
WEDNESDAY...MVFR CIGS. CHANCE -SN OR -RASN EARLY WITH IFR
POSSIBLE. VFR/WX NIL LATE. SW WINDS.
THURSDAY...MVFR CIGS PSBL IN THE MORNING. W WINDS.
FRIDAY/SATURDAY...VFR/WX NIL. W WINDS.
SUNDAY...LAKE EFFECT SNOW SHOWERS PSBL MAINLY ALONG AND EAST OF
THE TERMINALS WITH MVFR CIGS. OTHERWISE VFR WITH NW WINDS.
KMD
&&
.MARINE...
416 AM CST
A STRONG PRESSURE GRADIENT BETWEEN ARCTIC HIGH PRESSURE IN
SOUTHERN ONTARIO AND DEEP LOW PRESSURE OVER THE ARKLATEX REGION
WILL STRENGTHEN TODAY AS THE LOW SHIFTS NORTHWARD THROUGH THE DAY
AND THE HIGH SHIFTS EASTWARD. GALE FORCE WINDS WILL INCREASE OVER
THE ENTIRE LAKE TODAY...WITH STORM FORCE WINDS EXPECTED FOR A
TIME THIS AFTERNOON AND EARLY EVENING ACROSS THE SOUTHERN HALF OF
THE LAKE.WITH A STRONG EAST FETCH...THESE WINDS LOOK TO AFFECT THE
ILLINOIS NEARSHORE AS WELL. THESE STRONG WINDS WILL RESULT IN
WAVES POSSIBLY REACHING NEAR 20 FT OVER THE SOUTH HALF OF THE
LAKE AND ILLINOIS NEARSHORE. THERE MAY BE A BRIEF PERIOD OF STORM
FORCE GUSTS THIS EVENING ACROSS THE NORTH...BUT HAVE HELD TO THE
GALE WARNING FOR THE NORTH HALF AS THE WINDOW APPEARS TO BE
SHORTER THAN FOR THE SOUTH HALF. THE LOW WILL PUSH NORTHEAST OVER
THE LAKE OVERNIGHT THEN NORTHEAST OF THE LAKE ON TUESDAY...AND
THIS WILL ALLOW WINDS AND WAVES TO SUBSIDE SIGNIFICANTLY AFTER
THIS POINT. MODERATE WESTERLY FLOW WILL CONTINUE OVER THE LAKE
FOR MUCH OF THE LATTER HALF OF THE WEEK.
KMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...LAKESHORE FLOOD WARNING...ILZ006-ILZ014 UNTIL MIDNIGHT TUESDAY.
WINTER STORM WARNING...ILZ013-ILZ014-ILZ021-ILZ022-ILZ023 UNTIL
3 PM MONDAY.
HIGH WIND WARNING...ILZ006-ILZ014 UNTIL 7 PM MONDAY.
WINTER STORM WARNING...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ019-ILZ020 UNTIL 6 PM MONDAY.
WIND ADVISORY...ILZ013-ILZ021-ILZ022-ILZ023-ILZ032-ILZ033-ILZ039
UNTIL 6 PM MONDAY.
FREEZING RAIN ADVISORY...ILZ033-ILZ039 UNTIL NOON MONDAY.
FLASH FLOOD WATCH...ILZ033-ILZ039 UNTIL 6 PM MONDAY.
FREEZING RAIN ADVISORY...ILZ032 UNTIL 3 PM MONDAY.
IN...WIND ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL 6 PM
MONDAY.
WINTER STORM WARNING...INZ001-INZ002 UNTIL 3 PM MONDAY.
FLASH FLOOD WATCH...INZ010-INZ011-INZ019 UNTIL 6 PM MONDAY.
FREEZING RAIN ADVISORY...INZ010-INZ011-INZ019 UNTIL NOON MONDAY.
LM...STORM WARNING...ILLINOIS NEARSHORE WATERS UNTIL 9 PM MONDAY.
GALE WARNING...INDIANA NEARSHORE WATERS UNTIL 9 PM MONDAY.
STORM WARNING...LMZ777-LMZ779 UNTIL MIDNIGHT TUESDAY.
&&
$$
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AREA FORECAST DISCUSSION
National Weather Service Lincoln IL
1044 AM CST MON DEC 28 2015
.UPDATE...
ISSUED AT 1037 AM CST MON DEC 28 2015
Intensifying low pressure system currently along the
Arkansas/Missouri border, feeding plenty of moisture into the
region and perpetuating a lot of rainfall. Flooding of area rivers
ongoing and forecast, as well as intense winds out of the ENE,
gusting to near 50 mph at times. Freezing temps across the
northern tier of the state resulting in some ice accumulations,
although accumulation totals for ice over ILX counties remains
relatively light. Glazing and a tenth or so has been reported in
Knox, Woodford, and McLean counties. Going forecast is doing well
with some chance for fzra across the north, mixed in with mostly
rain through noon, and dwindling chances for fzra as the day
progresses. At this point, updates are not anticipated, but will
have to watch the temps in the extreme north for lingering near
the freezing mark, and adjust the precip types accordingly.
&&
.SHORT TERM...(Today)
ISSUED AT 343 AM CST MON DEC 28 2015
Rain has overspread the entire forecast area early this morning.
Galesburg temperature has dropped to 32, so some freezing rain
occurring there. Sleet may be mixing with rain north of a line from
Canton to Bloomington, but no confirmation is apparent in the web-
cameras that are available. Bloomington`s observation has carried
`unknown precipitation` for several hours already this morning with
air temps down to 33, so some sleet possibly occurring there.
The 00z NAM came in with warmer surface temps than previous model
runs, but the RAP and GFS keep a colder airmass across our northern
counties through the morning, supporting the winter weather scenario
in our headline products. Even the NAM still supports some freezing
rain with a mix of sleet this morning north of Peoria. We may see
slightly less ice than a quarter inch across the winter storm
warning area, but the impacts from any amount of ice could be large
due to the strong winds blowing the trees and power lines around
with any amount of ice. We will be keeping the headlines going
without any changes this morning. Winter storm warning for freezing
rain and sleet from Peoria and north until 3 pm looks fine, with a
freezing rain advisory from Fulton to McLean counties until noon
looking ok too.
The track of the surface low from south to north up the Mississippi
River Valley supports some thunder potential in our eastern and
southern counties through the day, with locally heavy rain still
possible. It also supports a surge of warm air into our entire
forecast area this afternoon, helping to shut down any additional
wintry precipitation. Impacts from any ice accumulation could last
after surface temperatures climb above freezing, due to strong winds
affecting icy trees and power lines.
A dry slot is forecast to progress from south to north through
Illinois this afternoon, so we diminished precip chances
accordingly. Areas north of I-74 should see precip linger until
evening.
.LONG TERM...(Tonight through Sunday)
ISSUED AT 343 AM CST MON DEC 28 2015
Strong surface low pressure of 997 mb over southeast OK to lift ne
into west central IL early this evening and lift across nw IL during
this evening. Low pressure will then weaken to 1002 mb as it lifts
into west central lower MI by 12Z/6 am Tue. Rain will diminish
quickly from sw to ne during this evening, with highest pops north
of I-74 early this evening, and just 20-30% chances of light
precipitation lingering overnight from I-74 northeast. Enough cold
air present to give a chance of light snow too over the IL river
valley tonight but little or no accumulations expected nw of the IL
river. Winds will drop off below wind advisory criteria by 6 pm and
become sw 15-25 mph by overnight. Went a few degrees cooler for lows
tonight ranging from near 30F far western CWA to the mid to upper
30s from I-57 east, with mildest readings near the Wabash river.
Breezy sw winds and clouds continue to linger over central IL on Tue
in wake of strong storm system pulling ne across Lake Huron, but
should be dry. Temperatures not expected to climb but a few degrees
on Tue with highs in the low to mid 30s west of I-57 and upper
30s/lower 40s east of I-57. Dry conditions continue on Tue night as
sw winds diminish. An approaching short wave from the Pacific states
to keep clouds around, with light snow chances just west of IL
overnight Tue night. Lows Tue night range from mid 20s over IL river
valley to lower 30s from I-70 southeast.
A large short wave lifts ne across IL and into lower MI during Wed
but has limited moisture over IL so will continue small chances (20-
30%) of light precipitation, mainly light snow central IL and chance
of light rain/snow in eastern/se IL. A fair amount of clouds again
on Wed with highs ranging from lower 30s over IL river valley to
around 40F in southeast IL.
Extended forecast models continue to show a large upper level trof
dominating the northeast half of the country during the 2nd half of
the week. Also large Canadian high pressure over the Rockies and
ridging into the southern plains to keep a cooler nw flow over IL
from Thu into New Years weekend. Temperatures averaging a bit below
normal for a change especially Thu/Fri when highs as cold as mid to
upper 20s in central IL and lows in the teens. Brunt of light snow
chances stays ne of central IL over the Great Lakes region late this
work week but could see more clouds linger still on Thu especially
in ne CWA, before mostly sunny skies eventually arrives Fri into the
weekend.
&&
.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
ISSUED AT 600 AM CST MON DEC 28 2015
Steady rains will continue today at all terminal sites. Freezing
rain will be mainly focused north of a line from Peoria to
Bloomington this morning, before temperatures rise well above
freezing this afternoon. Light glazing will be mainly above the
ground at the terminal sites of PIA and BMI, but spotty slippery
conditions could develop on bridges and overpasses this morning.
MVFR clouds are expected to dip to IFR by 14-15z, and remain IFR
for a majority of the day. BMI has already dropped to IFR cloud
levels and should remain there until later evening.
Rain chances will diminish from south to north starting after 3
pm/21z, as a dry slot wraps into Illinois.
The other major impact from this storm will be with the strong
and gusty easterly winds this morning as the storm approaches. We
expect easterly winds of 25 to 35 kts with gusts to 45 kts this
morning, as the most intense precip moves over the area. Winds
should become southeast to south later this afternoon as the
storm system shifts to our north with speeds gradually to
decreasing to between 15 and 25 kts by 03z. Wind direction will
eventually become westerly after 03z.
&&
.ILX Watches/Warnings/Advisories...
Flash Flood Watch until 6 PM CST this evening for ILZ044>046-049-
050-052>057-061>063-066>068-071>073.
Wind Advisory until 6 PM CST this evening for ILZ027>031-036>038-
040>057-061.
Winter Storm Warning until 3 PM CST this afternoon for
ILZ027>031.
Flash Flood Watch through this evening for ILZ051.
Freezing Rain Advisory until noon CST today for ILZ036>038.
&&
$$
UPDATE...HJS
SHORT TERM...Shimon
LONG TERM...07
AVIATION...Shimon
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1013 AM CST MON DEC 28 2015
.UPDATE...
955 AM CST
MONITORING OBSERVATIONAL TRENDS THIS MORNING AND FORECAST IS
LARGELY ON TRACK. HOWEVER...BASED ON REPORTS VIA EMERGENCY
MANAGERS AND SOCIAL MEDIA...AND EXPECTED NEAR TERM TEMPERATURE
TRENDS...WILL BE UPGRADING THE FREEZING RAIN ADVISORY TO A WINTER
STORM WARNING IN KANKAKEE AND LAKE AND PORTER COUNTIES THROUGH 3PM
CST. LATEST SPC/RAP MESOANALYSIS INDICATES ANTICIPATED WARMING OF
MAX WET BULB T ALOFT GRADUALLY LIFTING NORTHWARD...BUT THIS WILL
BE COUNTERACTED BE STRONG EASTERLY FLOW PULLING ON FEED OF LOWER
DEWPOINT AIR OVER NORTHERN INDIANA AND ASSOCIATED SURFACE
WETBULBING EFFECTS. WIDESPREAD 30-32 READINGS COULD REMAIN IN
PLACE THROUGH AT LEAST 18Z...AND EVEN AS LATE AS 20Z IF RECENT
RAP/HRRR RUNS ARE ON THE RIGHT TRACK. AS MENTIONED EARLIER...HAVE
RECEIVED MULTIPLE REPORTS OF VERY SLIPPERY ROADWAYS IN NW
INDIANA...AND ALSO SEVERAL REPORTS/PHOTOS ON SOCIAL MEDIA OF ICE
ACCUMULATION IN KANKAKEE COUNTY. WILL LEAVE FREEZING RAIN
ADVISORIES SOUTH OF THIS AREA IN PLACE WITH NO CHANGES...BUT WILL
BE MONITORING TEMP TRENDS CLOSELY.
FARTHER NORTH...MAINLY SLEET AND FREEZING RAIN HAS BEEN
OBSERVED...THOUGH RIGHT ALONG THE WISCONSIN STATE LINE SNOW HAS
BEEN PREDOMINANT PRECIPITATION TYPE. WOULD EXPECT TRANSITION TO
SLEET AND THEN FREEZING RAIN/SLEET TO COMMENCE...THOUGH WILL
CONTINUE TO MONITOR TRENDS. TOTAL SNOW/SLEET ACCUMS IN THE FAR
NORTH STILL APPEAR ON TRACK TO TOP OUT IN THE 1-2...LOCALLY 3 INCH
RANGE.
SURFACE LOW CURRENTLY OVER AR/MO BORDER LIFTING NORTH/NORTHEAST
WILL ONLY INCREASE MAGNITUDE OF PRESSURE FALLS AND ALREADY STRONG
EASTERLY WINDS GUSTING UP TO 45 MPH ALONG THE ILLINOIS SHORE. NO
CHANGES TO ONGOING WIND AND LAKESHORE FLOODING HEADLINES.
FINALLY...THERE HAVE BEEN SPORADIC CG LIGHTNING STRIKES ACROSS
CENTRAL IL AND INDIANA THIS MORNING IN STRONG WAA REGIME. AS DRY
SLOT OF IMPRESSIVE MID LATITUDE CYCLONE APPROACHES THIS
AFTERNOON...STEEPENING MID LEVEL LAPSE RATES WILL LIKELY YIELD AN
UPTICK IN OVERALL THUNDER COVERAGE. HIGH-RES GUIDANCE DEPICTS THIS
WELL AND THIS WILL BE SOMETHING TO WATCH FOR IN TERMS OF CAUSING
RAPID CHANGES IN P-TYPES...ESPECIALLY WITH NORTHWARD AND WESTWARD
EXTENT WHERE LOW LEVEL COLD WILL LINGER THE LONGEST.
OVERALL...STILL HAVE LOWER CONFIDENCE ON HOW LONG IT WILL TAKE FOR
NORTHWEST 1/3 OF CWA TO TRANSITION OVER TO PLAIN RAIN...LATEST MAY
BE 7-8PM.
CASTRO/RODRIGUEZ
&&
.SHORT TERM...
401 AM CST
THROUGH TUESDAY...
A MAJOR WIND AND ICE EVENT FOR A GOOD PORTION OF THE AREA...ALONG
WITH SOME OTHER ACCOMPANYING IMPACTS...IS BEGINNING TO UNFOLD INTO
THE REGION EARLY THIS MORNING. NO CHANGES PLANNED TO THE SPATIAL
EXTENT OF THE CURRENT MYRIAD OF HEADLINES...AS THEY COVER THIS
DYNAMIC SYSTEM WELL...WITH JUST SOME MINOR SHIFTS TO TIMING TO
COVER PRIME THREAT TIMES. WE ARE AT THE STAGE NOW OF INCORPORATING
OBSERVATIONAL TRENDS INTO THE GOING FORECAST WITH HOPEFULLY
ADJUSTMENTS MORE SO THAN MAJOR SHIFTS...AND THUS FAR THAT IS THE
CASE. HOWEVER BEING IN A TRANSITIONAL PRECIPITATION EVENT WHERE
SPECIFIC SURFACE AND ALOFT TEMPERATURES PLAY CRITICAL ROLES MAKES
THIS PARTICULARLY CHALLENGING.
THE MOST NOTEWORTHY CHANGES/OBSERVATIONS IN SUMMARY ARE THE OVERALL
FORECAST PRECIPITATION AMOUNTS HAVE BEEN INCREASED AREAWIDE LATE
MORNING THROUGH THE AFTERNOON AS IT IS MORE APPARENT CONVECTIVE
ELEMENTS AND SLANTWISE INSTABILITY WILL IMPINGE INTO THE AREA. THE
OVERLAP AREA OF THESE HEAVIER INTENSITY/AMOUNTS AND THE STILL COLD
ENOUGH FOR FREEZING RAIN APPEARS TO BE ALONG/NORTH OF INTERSTATE
80 AND ALONG AND WEST OF ILLINOIS 47...SO HAVE BUMPED UP FORECAST
ICE ACCUMULATIONS IN THESE AREAS AND PLACED HEAVY WORDING IN THE
FORECAST. HAVE ALSO ADDED ISOLATED/SCATTERED THUNDER...ALTHOUGH
THAT SHOULD BE MAINLY AFTER THE PEAK ICING TIME.
ALSO CONTINUED AN ADJUSTMENT OF A BIT SLOWER TEMPERATURE RECOVERY
IN THE IMMEDIATE LOW-LEVELS RESULTING IN LONGER SLEET DURATION
ALONG AND NORTH OF I-88...WITH THAT POTENTIALLY THE DOMINANT
PRECIPITATION TYPE MOST OF THE MORNING IN THAT REGION. HAVE UPPED
SLEET ACCUMULATION TO AROUND AN INCH THOUGH HIGHER TOTALS
CERTAINLY POSSIBLE DEPENDING ON RATE. WHILE IMPACTS DURING THE
MORNING MAY BE LESS IF THIS MAINLY SLEET/INTERMITTENT SNOW
MATERIALIZES...THE ICING POTENTIAL IN THE AFTERNOON WITH STRONG
WINDS STILL LOOKS ON TRACK.
A VERY POTENT SYSTEM IN ALMOST EVERY DEFINITION IS CENTERED OVER
THE ARKLATEX EARLY THIS MORNING...WHICH WILL HAVE A TRACK RECORD
WHEN IT IS FINISHED LATE TONIGHT WITH AFFECTING ALMOST EVERY
CENTRAL CONUS STATE WITH SOME FORM OF IMPACTING WEATHER. A 70
DEGREE TEMPERATURE DIFFERENCE FROM NORTHWEST IOWA TO NORTHERN
MISSISSIPPI EARLY THIS MORNING HIGHLIGHTS THE BAROCLINICITY THAT
THE WARM AND MOIST ADVECTION IS OVERRIDING INTO OUR AREA.
PRECIPITATION WITH THE LEADING EDGE OF THIS IN THE SOUTHERN CWA
HAS BEEN A LIGHT MIXED BAG THUS FAR. NEAR DAYBREAK INTENSITY LOOKS
TO UPTICK IN RESPONSE TO INCREASING DIFFLUENCE AND LOWER TO MID-
LEVEL F-GEN. THIS WILL CAUSE A PRONOUNCED WET-BULBING COOLING
EFFECT AS INHERENT DRY AIR BECOMES SATURATED WITHIN THE LOW-LEVEL
NORTHEAST FLOW. EARLY MORNING AMDAR DATA NEAR CHICAGO INDICATE A
WARM NOSE AROUND 2C ALOFT AND A LOW-LEVEL COLD NOSE AROUND -5C...
BOTH OF WHICH THE RAP SEEMS TO BE INITIALIZING WELL WITH OVER ITS
PAST FEW RUNS...LENDING SOME CONFIDENCE OF FINE TUNING THE
FORECAST TOWARD IT THIS MORNING. THE VERTICAL PROFILES AND
EXPECTED UPTICK IN PRECIP INTENSITY SHOULD CAUSE THE MAIN TYPE AT
FIRST TO BE ICE PELLETS OR EVEN SOME LIGHT SNOW /WHICH HAS BEEN
REPORTED/. BEING WITHIN THE LOW-LEVEL CONVEYOR BELT OF THIS MATURE
SYSTEM THIS MORNING...WITH 45 KT NORTHEAST 925MB FLOW PER
PROFILERS...THIS SEEMS TO SUPPORT THE TREND FOR P-TYPE TO WANT TO
REMAIN AS SLEET WITH OCCASIONAL SNOW IN FAR NORTHERN PARTS OF THE
CWA INTO LATE MORNING WITH MINOR ACCUMULATIONS. MORE IMPORTANTLY
FOR IMPACTS IT ALSO KEEPS THE FREEZING RAIN CORRIDOR IN PLACE TO
THE SOUTH OF THIS...THROUGH THE MORNING AND EVEN POTENTIALLY EARLY
AFTERNOON. TO HELP VISUALIZE...THIS IS ROUGHLY 30 MILES OR SO
NORTH OR SOUTH OF INTERSTATE 80.
THE AREAS IN THE SHADOW OF THE LAKE...INCLUDING CENTRAL AREAS OF
THE CHICAGO METRO...STILL LOOK LIKE THEY COULD STRUGGLE TO SEE
TEMPERATURES DROP MUCH DUE TO THE STRONG ADVECTION FROM THE
LAKE...SO ICING IS A LITTLE LESS OF A THREAT FOR THESE IMMEDIATE
NEARSHORE LOCATIONS...INCLUDING DOWNTOWN. HOWEVER WIND SPEEDS WILL
BE THE MAXIMUM...GUSTING TO IMPRESSIVE MAGNITUDES TO 50 TO 60 MPH
THIS AFTERNOON AND EARLY EVENING.
THE INGREDIENTS FOR THE WINDS TODAY AND INTO EARLY EVENING CONTINUE
TO JUST BE TRULY STRIKING. PRESSURE FALLS OF AROUND 15MB ARE
FORECAST BETWEEN 10AM AND 3PM OVER MUCH OF THE CWA THIS AFTERNOON.
HAVE CONTINUED WITH FORECAST HIGH END WIND GUSTS AND CORRELATED
DUAL IMPACT WITH ANY ICED LINES AND LIMBS. WIDESPREAD POWER
OUTAGES STILL LOOK POTENTIALLY REALIZED WHERE THE HEAVIER ICE
ACCUMULATIONS OCCUR.
AS THE STACKED SYSTEM CENTER AND ASSOCIATED DEEP TROPOSPHERIC FOLD
MOVES TOWARD THE AREA MID-AFTERNOON...THE WARM MOIST CONVEYOR
BELT NOSE PUSHES INTO THE AREA WITH SOME HEAVY PRECIPITATION AGAIN
LIKELY. ELEVATED INSTABILITY VALUES SUPPORT THUNDER INCLUSION. THE
LOW WILL PASS OVER WITH WINDS THEN EASING. FORCING LOOKS ENOUGH
STILL TO WARRANT SCATTERED RAIN SHOWERS ACROSS THE AREA AND
POSSIBLY EVEN SOME DRIZZLE. THE CHANCE FOR SOME OF THIS TO BE SNOW
SHOWERS INCREASES OVERNIGHT...ALTHOUGH THE INTENSITY SHOULD BE
LIGHT ENOUGH WITH MARGINAL SURFACE TEMPERATURES TO NOT REALLY HAVE
ANY ACCUMULATION. SOME OF THESE SHOWERS MAY LINGER INTO TUESDAY
MORNING...WITH WRAPAROUND COLD ADVECTION KEEPING TEMPERATURES
FROM RISING ANY AND HIGHS IN THE 30S.
MTF
&&
.LONG TERM...
204 AM CST
WEDNESDAY THROUGH SUNDAY...
THE MAIN FEATURE OF THE EXTENDED FORECAST PERIOD IS THE
ESTABLISHMENT OF AN EASTERN NORTH AMERICAN MEAN TROUGH...WITH
UPPER RIDGING BUILDING ACROSS THE NORTHWESTERN U.S. AND WESTERN
CANADA. THIS SETS THE STAGE FOR A PERIOD OF BELOW-AVERAGE COLD
THURSDAY THROUGH SUNDAY...THE FIRST MULTIPLE DAY STRETCH OF
BELOW AVERAGE TEMPERATURES FOR OUR AREA SINCE THE WEEK BEFORE
THANKSGIVING.
BY WEDNESDAY MORNING...THE OCCLUDED SURFACE LOW PRESSURE
ASSOCIATED WITH OUR NEAR TERM WINTER STORM WILL BE FILLING OVER
THE NORTHERN GREAT LAKES...WITH ITS TRAILING COLD FRONT EAST OF
THE FORECAST AREA. ANOTHER MID-LEVEL SHORT WAVE IS PROGGED TO
LIFT OUT OF THE LARGE WESTERN CONUS UPPER TROUGH DURING THE
MORNING...AND EVENTUALLY TAKING THE OLD SURFACE LOW OFF TO THE
NORTHEAST OF THE REGION. 00Z GFS/ECMWF AND GEM RUNS ARE ALL VERY
SIMILAR IN GENERATING AN AXIS OF LIGHT QPF BETWEEN 0.01-0.07"
ACROSS PARTS OF NORTH CENTRAL AND NORTHEAST ILLINOIS DURING THE
MORNING...MAINLY NORTHWEST OF THE I-55 CORRIDOR. USING A MODEL
BLEND QPF AND COBB OUTPUT SNOW/LIQUID RATIOS FROM ROUGHLY 11-13:1
ACROSS THE MAIN QPF AXIS DURING THE PERIOD...SUPPORTING A FEW
TENTHS OF AN INCH OF SNOW ACCUMULATION PERHAPS UP TO A HALF
INCH NORTHWEST OF THE CHICAGO AREA IN THE 12-18Z PERIOD. ONLY A
FEW FLURRIES PERHAPS LINGERING AT MIDDAY/EARLY AFTERNOON.
THE LONG WAVE UPPER TROUGH EVOLVES EASTWARD ACROSS CENTRAL NORTH
AMERICA WEDNESDAY NIGHT AND THURSDAY...EVENTUALLY BECOMING
ELONGATED IN A POSITIVE-TILT SOUTHWEST-NORTHEAST ORIENTATION BY
FRIDAY WITH THE TROUGH AXIS MOVING SOUTHEAST OF THE FORECAST
AREA. AT THE SURFACE...SURFACE LOW PRESSURE ASSOCIATED WITH
WEDNESDAYS DISTURBANCE PULLS AWAY TO THE EAST...WITH A BROAD
REGION OF COLDER WEST-NORTHEAST LOW LEVEL FLOW EAST OF STRONG
SURFACE HIGH PRESSURE DEVELOPING ACROSS THE NORTHERN AND
CENTRAL HIGH PLAINS. WHILE A FEW MINOR AMPLITUDE DISTURBANCES
APPEAR TO MOVE THROUGH THE FLOW ALOFT...LOW LEVELS ARE DOMINATED
BY COLDER...DRIER MODIFIED ARCTIC AIR AND LITTLE IN THE WAY OF
ORGANIZED PRECIP CHANCES ARE NOTED THROUGH THE WEEKEND. COLD
AIR...APPROACHING -10 TO -12 C AT 850 MB BY EARLY FRIDAY...
WILL LIKELY SUPPORT LAKE EFFECT SNOW SHOWERS DOWNWIND OF THE
LAKE ACROSS LOWER MICHIGAN. AS INDICATED ABOVE...THE PERIOD
FROM THURSDAY THROUGH SATURDAY LOOKS TO BE OUR FIRST MULTI-DAY
STRETCH OF BELOW AVERAGE TEMPS IN OVER A MONTH. MODEL LOW LEVEL
THERMAL PROGS AND GFS/ECMWF MOS NUMBERS DEPICT HIGHS IN THE 20S
THUR-FRI WITH LOWS IN THE TEENS AND EVEN A FEW SINGLE DIGITS
IN OUR TYPICALLY COLDEST SPOTS. AVERAGE TEMPS AROUND THE FIRST
OF THE YEAR ARE 30/14 AT ROCKFORD AND 31/17 FOR CHICAGO.
RATZER
&&
.HYDROLOGY...
A POWERFUL STORM SYSTEM WILL DRAW COPIOUS AMOUNTS OF MOISTURE
NORTHWARD ON MONDAY. SOME OF THE PRECIPITATION WILL FALL AS SLEET
AND FREEZING RAIN. TOTAL FORECAST LIQUID EQUIVALENT AMOUNTS ARE IN
THE 1 TO 1.5 INCH RANGE ACROSS NORTHERN AND CENTRAL ILLINOIS AND
NORTHWEST INDIANA. WITH SUCH ANOMALOUSLY HIGH MOISTURE
LEVELS...LOCALLY HIGHER TOTALS ARE PROBABLE. 24-HOUR RAIN AMOUNTS
FROM SATURDAY INTO SUNDAY MORNING WERE UP TO 2-3 INCHES SOUTH OF
THE KANKAKEE RIVER. THIS RAIN HAS ALREADY RESULTED IN RISES ON
RIVERS AND STREAMS IN THIS AREA. THE ADDITIONAL RAIN ON MONDAY
WILL EXACERBATE AND PROLONG ONGOING RISES. FOR AREAS FARTHER
NORTH...RIVER AND STREAM LEVELS ARE ALREADY RUNNING ABOVE
NORMAL...AND THE HEAVY FORECAST PRECIPITATION WILL RESULT IN
RENEWED RISES.
RC
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* MVFR CIGS CONTINUE TO LOWER TOWARDS IFR BY LATE MORNING AND
POSSIBLY INTO LIFR THIS AFTERNOON.
* IFR VSBYS IN PRECIPITATION LATE MORNING.
* ENE WINDS WITH GUSTS 30-35 KT...35-40 KT IN THE AFTERNOON.
* WINTRY MIX OF PCPN. LIGHT FZRA WILL BECOME MODERATE IN POCKETS
THRU EARLY AFTERNOON. PCPN SHOULD TRANSITION TO ALL LIQUID BY
EARLY TO MID AFTERNOON.
* ISOLATED TSRA LATER THIS AFTERNOON.
MM
//DISCUSSION...UPDATED 12Z...
CONCERNS INITIALLY AROUND PRECIPITATION TYPE THIS MORNING. A MIXED
BAG IS BEING REPORTED AROUND THE AREA...WITH LIQUID PRECIPITATION
THE MAIN PRECIPITATION TYPE ALONG THE FAR SOUTHERN AREAS SOUTH OF
I-80 WHERE SURFACE TEMPERATURES ARE HOVERING RIGHT AROUND
FREEZING. ALONG THE I-80 TO I-90 CORRIDOR CLOSER TO CHICAGO P-TYPE
IS MAINLY SLEET...THEN A NOW SLEET MIX FARTHER NORTH AND WEST
TOWARD ROCKFORD AND WISCONSIN. EXPECT THAT AS THE WARM LAYER ALOFT
SPREADS NORTH THAT SLEET WILL TRANSITION TO FZRA/RA. MARGINAL
SURFACE TEMPERATURES SHOULD PRECLUDE A SIGNIFICANT ICE THREAT
CLOSER TO CHICAGO BUT ACCUMS REMAIN POSSIBLE...ESPECIALLY AS RATES
INCREASE AND SOME ADDITIONAL LOW LEVEL COOLING OCCURS. SLEET
ACCUMULATIONS HAVE OCCURRED AND WILL CONTINUE AT LEAST FOR A FEW
MORE HOURS. -SN/PL HANG ON LONGEST NORTHWEST...THEN A TRANSITION
TO RA THIS AFTERNOON. EVEN A TS CHANCE IN THE MID TO LATE
AFTERNOON.
OTHER CONCERN IS THE STRONG WINDS THAT WILL RAMP UP THIS MORNING
AND EVEN MORE SO THIS AFTERNOON. EXPECT GUSTS IN THE 30 KT RANGE
THEN TRANSITIONING TO POSSIBLY 40 KT THIS AFTERNOON...ESPECIALLY
CLOSER TO THE LAKE. CIGS WILL CONTINUE TO LOWER TO LOWER END
MVFR...THEN IFR AND EVEN LIFR LATER TODAY. VSBYS SHOULD LARGELY
HOLD MVFR FOR SOME TIME EXCEPT WEST IN THE HEAVIER PRECIPITATION
THAT IS SNOW AND AS PRECIP RATES INTENSIFY MID TO LATE MORNING.
WINDS SLACKEN TONIGHT AND TURN SOUTHWEST WITH PRECIP RATES
DECREASING...THOUGH THERE SHOULD BE A TRANSITIONING TO RA/SN MIX
OVERNIGHT.
KMD
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* MEDIUM TO HIGH CONFIDENCE IN CIG TRENDS...MEDIUM ON TRANSITION
TIMES.
* HIGH IN OCCURRENCE OF IFR VSBYS...BUT LOW ON THE LENGTH OF TIME
FOR LESS THAN 1SM VSBY.
* HIGH CONFIDENCE IN WIND TRENDS.
* HIGH CONFIDENCE IN MIXED/FREEZING PRECIP. MEDIUM HIGH IN
TIMING OF PCPN TYPE CHANGES.
* MEDIUM CONFIDENCE IN ISOLATED TS THIS AFTERNOON...BUT LOW
CONFIDENCE IN OCCURRENCE AT THE TERMINALS.
MM
//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...
TUESDAY NIGHT...VFR. SW WINDS.
WEDNESDAY...MVFR CIGS. CHANCE -SN OR -RASN EARLY WITH IFR
POSSIBLE. VFR/WX NIL LATE. SW WINDS.
THURSDAY...MVFR CIGS PSBL IN THE MORNING. W WINDS.
FRIDAY/SATURDAY...VFR/WX NIL. W WINDS.
SUNDAY...LAKE EFFECT SNOW SHOWERS PSBL MAINLY ALONG AND EAST OF
THE TERMINALS WITH MVFR CIGS. OTHERWISE VFR WITH NW WINDS.
KMD
&&
.MARINE...
416 AM CST
A STRONG PRESSURE GRADIENT BETWEEN ARCTIC HIGH PRESSURE IN
SOUTHERN ONTARIO AND DEEP LOW PRESSURE OVER THE ARKLATEX REGION
WILL STRENGTHEN TODAY AS THE LOW SHIFTS NORTHWARD THROUGH THE DAY
AND THE HIGH SHIFTS EASTWARD. GALE FORCE WINDS WILL INCREASE OVER
THE ENTIRE LAKE TODAY...WITH STORM FORCE WINDS EXPECTED FOR A
TIME THIS AFTERNOON AND EARLY EVENING ACROSS THE SOUTHERN HALF OF
THE LAKE.WITH A STRONG EAST FETCH...THESE WINDS LOOK TO AFFECT THE
ILLINOIS NEARSHORE AS WELL. THESE STRONG WINDS WILL RESULT IN
WAVES POSSIBLY REACHING NEAR 20 FT OVER THE SOUTH HALF OF THE
LAKE AND ILLINOIS NEARSHORE. THERE MAY BE A BRIEF PERIOD OF STORM
FORCE GUSTS THIS EVENING ACROSS THE NORTH...BUT HAVE HELD TO THE
GALE WARNING FOR THE NORTH HALF AS THE WINDOW APPEARS TO BE
SHORTER THAN FOR THE SOUTH HALF. THE LOW WILL PUSH NORTHEAST OVER
THE LAKE OVERNIGHT THEN NORTHEAST OF THE LAKE ON TUESDAY...AND
THIS WILL ALLOW WINDS AND WAVES TO SUBSIDE SIGNIFICANTLY AFTER
THIS POINT. MODERATE WESTERLY FLOW WILL CONTINUE OVER THE LAKE
FOR MUCH OF THE LATTER HALF OF THE WEEK.
KMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...LAKESHORE FLOOD WARNING...ILZ006-ILZ014 UNTIL MIDNIGHT TUESDAY.
WINTER STORM WARNING...ILZ013-ILZ014-ILZ021-ILZ022-ILZ023 UNTIL
3 PM MONDAY.
HIGH WIND WARNING...ILZ006-ILZ014 UNTIL 7 PM MONDAY.
WINTER STORM WARNING...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ019-ILZ020 UNTIL 6 PM MONDAY.
WIND ADVISORY...ILZ013-ILZ021-ILZ022-ILZ023-ILZ032-ILZ033-ILZ039
UNTIL 6 PM MONDAY.
FREEZING RAIN ADVISORY...ILZ033-ILZ039 UNTIL NOON MONDAY.
FLASH FLOOD WATCH...ILZ033-ILZ039 UNTIL 6 PM MONDAY.
FREEZING RAIN ADVISORY...ILZ032 UNTIL 3 PM MONDAY.
IN...WIND ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL 6 PM
MONDAY.
WINTER STORM WARNING...INZ001-INZ002 UNTIL 3 PM MONDAY.
FLASH FLOOD WATCH...INZ010-INZ011-INZ019 UNTIL 6 PM MONDAY.
FREEZING RAIN ADVISORY...INZ010-INZ011-INZ019 UNTIL NOON MONDAY.
LM...STORM WARNING...ILLINOIS NEARSHORE WATERS UNTIL 9 PM MONDAY.
GALE WARNING...INDIANA NEARSHORE WATERS UNTIL 9 PM MONDAY.
STORM WARNING...LMZ777-LMZ779 UNTIL MIDNIGHT TUESDAY.
&&
$$
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1005 AM CST MON DEC 28 2015
.UPDATE...
955 AM CST
MONITORING OBSERVATIONAL TRENDS THIS MORNING AND FORECAST IS
LARGELY ON TRACK. HOWEVER...BASED ON REPORTS VIA EMERGENCY
MANAGERS AND SOCIAL MEDIA...AND EXPECTED NEAR TERM TEMPERATURE
TRENDS...WILL BE UPGRADING THE FREEZING RAIN ADVISORY TO A WINTER
STORM WARNING IN KANKAKEE AND LAKE AND PORTER COUNTIES THROUGH 3PM
CST. LATEST SPC/RAP MESOANALYSIS INDICATES ANTICIPATED WARMING OF
MAX WET BULB T ALOFT GRADUALLY LIFTING NORTHWARD...BUT THIS WILL
BE COUNTERACTED BE STRONG EASTERLY FLOW PULLING ON FEED OF LOWER
DEWPOINT AIR OVER NORTHERN INDIANA AND ASSOCIATED SURFACE
WETBULBING EFFECTS. WIDESPREAD 30-32 READINGS COULD REMAIN IN
PLACE THROUGH AT LEAST 18Z...AND EVEN AS LATE AS 20Z IF RECENT
RAP/HRRR RUNS ARE ON THE RIGHT TRACK. AS MENTIONED EARLIER...HAVE
RECEIVED MULTIPLE REPORTS OF VERY SLIPPERY ROADWAYS IN NW
INDIANA...AND ALSO SEVERAL REPORTS/PHOTOS ON SOCIAL MEDIA OF ICE
ACCUMULATION IN KANKAKEE COUNTY. WILL LEAVE FREEZING RAIN
ADVISORIES SOUTH OF THIS AREA IN PLACE WITH NO CHANGES...BUT WILL
BE MONITORING TEMP TRENDS CLOSELY.
FARTHER NORTH...MAINLY SLEET AND FREEZING RAIN HAS BEEN
OBSERVED...THOUGH RIGHT ALONG THE WISCONSIN STATE LINE SNOW HAS
BEEN PREDOMINANT PRECIPITATION TYPE. WOULD EXPECT TRANSITION TO
SLEET AND THEN FREEZING RAIN/SLEET TO COMMENCE...THOUGH WILL
CONTINUE TO MONITOR TRENDS. TOTAL SNOW/SLEET ACCUMS IN THE FAR
NORTH STILL APPEAR ON TRACK TO TOP OUT IN THE 1-2...LOCALLY 3 INCH
RANGE.
SURFACE LOW CURRENTLY OVER AR/MO BORDER LIFTING NORTH/NORTHEAST
WILL ONLY INCREASE MAGNITUDE OF PRESSURE FALLS AND ALREADY STRONG
EASTERLY WINDS GUSTING UP TO 45 MPH ALONG THE ILLINOIS SHORE. NO
CHANGES TO ONGOING WIND AND LAKESHORE FLOODING HEADLINES.
FINALLY...THERE HAVE BEEN SPORADIC CG LIGHTNING STRIKES ACROSS
CENTRAL IL AND INDIANA THIS MORNING IN STRONG WAA REGIME. AS DRY
SLOT OF IMPRESSIVE MID LATITUDE CYCLONE APPROACHES THIS
AFTERNOON...STEEPENING MID LEVEL LAPSE RATES WILL LIKELY YIELD AN
UPTICK IN OVERALL THUNDER COVERAGE. HIGH-RES GUIDANCE DEPICTS THIS
WELL AND THIS WILL BE SOMETHING TO WATCH FOR IN TERMS OF CAUSING
RAPID CHANGES IN P-TYPES...ESPECIALLY WITH NORTHWARD AND WESTWARD
EXTENT WHERE LOW LEVEL COLD WILL LINGER THE LONGEST.
OVERALL...STILL HAVE LOWER CONFIDENCE ON HOW LONG IT WILL TAKE FOR
NORTHWEST 1/3 OF CWA TO TRANSITION OVER TO PLAIN RAIN...LATEST MAY
BE 7-8PM.
CASTRO/RODRIGUEZ
&&
.SHORT TERM...
401 AM CST
THROUGH TUESDAY...
A MAJOR WIND AND ICE EVENT FOR A GOOD PORTION OF THE AREA...ALONG
WITH SOME OTHER ACCOMPANYING IMPACTS...IS BEGINNING TO UNFOLD INTO
THE REGION EARLY THIS MORNING. NO CHANGES PLANNED TO THE SPATIAL
EXTENT OF THE CURRENT MYRIAD OF HEADLINES...AS THEY COVER THIS
DYNAMIC SYSTEM WELL...WITH JUST SOME MINOR SHIFTS TO TIMING TO
COVER PRIME THREAT TIMES. WE ARE AT THE STAGE NOW OF INCORPORATING
OBSERVATIONAL TRENDS INTO THE GOING FORECAST WITH HOPEFULLY
ADJUSTMENTS MORE SO THAN MAJOR SHIFTS...AND THUS FAR THAT IS THE
CASE. HOWEVER BEING IN A TRANSITIONAL PRECIPITATION EVENT WHERE
SPECIFIC SURFACE AND ALOFT TEMPERATURES PLAY CRITICAL ROLES MAKES
THIS PARTICULARLY CHALLENGING.
THE MOST NOTEWORTHY CHANGES/OBSERVATIONS IN SUMMARY ARE THE OVERALL
FORECAST PRECIPITATION AMOUNTS HAVE BEEN INCREASED AREAWIDE LATE
MORNING THROUGH THE AFTERNOON AS IT IS MORE APPARENT CONVECTIVE
ELEMENTS AND SLANTWISE INSTABILITY WILL IMPINGE INTO THE AREA. THE
OVERLAP AREA OF THESE HEAVIER INTENSITY/AMOUNTS AND THE STILL COLD
ENOUGH FOR FREEZING RAIN APPEARS TO BE ALONG/NORTH OF INTERSTATE
80 AND ALONG AND WEST OF ILLINOIS 47...SO HAVE BUMPED UP FORECAST
ICE ACCUMULATIONS IN THESE AREAS AND PLACED HEAVY WORDING IN THE
FORECAST. HAVE ALSO ADDED ISOLATED/SCATTERED THUNDER...ALTHOUGH
THAT SHOULD BE MAINLY AFTER THE PEAK ICING TIME.
ALSO CONTINUED AN ADJUSTMENT OF A BIT SLOWER TEMPERATURE RECOVERY
IN THE IMMEDIATE LOW-LEVELS RESULTING IN LONGER SLEET DURATION
ALONG AND NORTH OF I-88...WITH THAT POTENTIALLY THE DOMINANT
PRECIPITATION TYPE MOST OF THE MORNING IN THAT REGION. HAVE UPPED
SLEET ACCUMULATION TO AROUND AN INCH THOUGH HIGHER TOTALS
CERTAINLY POSSIBLE DEPENDING ON RATE. WHILE IMPACTS DURING THE
MORNING MAY BE LESS IF THIS MAINLY SLEET/INTERMITTENT SNOW
MATERIALIZES...THE ICING POTENTIAL IN THE AFTERNOON WITH STRONG
WINDS STILL LOOKS ON TRACK.
A VERY POTENT SYSTEM IN ALMOST EVERY DEFINITION IS CENTERED OVER
THE ARKLATEX EARLY THIS MORNING...WHICH WILL HAVE A TRACK RECORD
WHEN IT IS FINISHED LATE TONIGHT WITH AFFECTING ALMOST EVERY
CENTRAL CONUS STATE WITH SOME FORM OF IMPACTING WEATHER. A 70
DEGREE TEMPERATURE DIFFERENCE FROM NORTHWEST IOWA TO NORTHERN
MISSISSIPPI EARLY THIS MORNING HIGHLIGHTS THE BAROCLINICITY THAT
THE WARM AND MOIST ADVECTION IS OVERRIDING INTO OUR AREA.
PRECIPITATION WITH THE LEADING EDGE OF THIS IN THE SOUTHERN CWA
HAS BEEN A LIGHT MIXED BAG THUS FAR. NEAR DAYBREAK INTENSITY LOOKS
TO UPTICK IN RESPONSE TO INCREASING DIFFLUENCE AND LOWER TO MID-
LEVEL F-GEN. THIS WILL CAUSE A PRONOUNCED WET-BULBING COOLING
EFFECT AS INHERENT DRY AIR BECOMES SATURATED WITHIN THE LOW-LEVEL
NORTHEAST FLOW. EARLY MORNING AMDAR DATA NEAR CHICAGO INDICATE A
WARM NOSE AROUND 2C ALOFT AND A LOW-LEVEL COLD NOSE AROUND -5C...
BOTH OF WHICH THE RAP SEEMS TO BE INITIALIZING WELL WITH OVER ITS
PAST FEW RUNS...LENDING SOME CONFIDENCE OF FINE TUNING THE
FORECAST TOWARD IT THIS MORNING. THE VERTICAL PROFILES AND
EXPECTED UPTICK IN PRECIP INTENSITY SHOULD CAUSE THE MAIN TYPE AT
FIRST TO BE ICE PELLETS OR EVEN SOME LIGHT SNOW /WHICH HAS BEEN
REPORTED/. BEING WITHIN THE LOW-LEVEL CONVEYOR BELT OF THIS MATURE
SYSTEM THIS MORNING...WITH 45 KT NORTHEAST 925MB FLOW PER
PROFILERS...THIS SEEMS TO SUPPORT THE TREND FOR P-TYPE TO WANT TO
REMAIN AS SLEET WITH OCCASIONAL SNOW IN FAR NORTHERN PARTS OF THE
CWA INTO LATE MORNING WITH MINOR ACCUMULATIONS. MORE IMPORTANTLY
FOR IMPACTS IT ALSO KEEPS THE FREEZING RAIN CORRIDOR IN PLACE TO
THE SOUTH OF THIS...THROUGH THE MORNING AND EVEN POTENTIALLY EARLY
AFTERNOON. TO HELP VISUALIZE...THIS IS ROUGHLY 30 MILES OR SO
NORTH OR SOUTH OF INTERSTATE 80.
THE AREAS IN THE SHADOW OF THE LAKE...INCLUDING CENTRAL AREAS OF
THE CHICAGO METRO...STILL LOOK LIKE THEY COULD STRUGGLE TO SEE
TEMPERATURES DROP MUCH DUE TO THE STRONG ADVECTION FROM THE
LAKE...SO ICING IS A LITTLE LESS OF A THREAT FOR THESE IMMEDIATE
NEARSHORE LOCATIONS...INCLUDING DOWNTOWN. HOWEVER WIND SPEEDS WILL
BE THE MAXIMUM...GUSTING TO IMPRESSIVE MAGNITUDES TO 50 TO 60 MPH
THIS AFTERNOON AND EARLY EVENING.
THE INGREDIENTS FOR THE WINDS TODAY AND INTO EARLY EVENING CONTINUE
TO JUST BE TRULY STRIKING. PRESSURE FALLS OF AROUND 15MB ARE
FORECAST BETWEEN 10AM AND 3PM OVER MUCH OF THE CWA THIS AFTERNOON.
HAVE CONTINUED WITH FORECAST HIGH END WIND GUSTS AND CORRELATED
DUAL IMPACT WITH ANY ICED LINES AND LIMBS. WIDESPREAD POWER
OUTAGES STILL LOOK POTENTIALLY REALIZED WHERE THE HEAVIER ICE
ACCUMULATIONS OCCUR.
AS THE STACKED SYSTEM CENTER AND ASSOCIATED DEEP TROPOSPHERIC FOLD
MOVES TOWARD THE AREA MID-AFTERNOON...THE WARM MOIST CONVEYOR
BELT NOSE PUSHES INTO THE AREA WITH SOME HEAVY PRECIPITATION AGAIN
LIKELY. ELEVATED INSTABILITY VALUES SUPPORT THUNDER INCLUSION. THE
LOW WILL PASS OVER WITH WINDS THEN EASING. FORCING LOOKS ENOUGH
STILL TO WARRANT SCATTERED RAIN SHOWERS ACROSS THE AREA AND
POSSIBLY EVEN SOME DRIZZLE. THE CHANCE FOR SOME OF THIS TO BE SNOW
SHOWERS INCREASES OVERNIGHT...ALTHOUGH THE INTENSITY SHOULD BE
LIGHT ENOUGH WITH MARGINAL SURFACE TEMPERATURES TO NOT REALLY HAVE
ANY ACCUMULATION. SOME OF THESE SHOWERS MAY LINGER INTO TUESDAY
MORNING...WITH WRAPAROUND COLD ADVECTION KEEPING TEMPERATURES
FROM RISING ANY AND HIGHS IN THE 30S.
MTF
&&
.LONG TERM...
204 AM CST
WEDNESDAY THROUGH SUNDAY...
THE MAIN FEATURE OF THE EXTENDED FORECAST PERIOD IS THE
ESTABLISHMENT OF AN EASTERN NORTH AMERICAN MEAN TROUGH...WITH
UPPER RIDGING BUILDING ACROSS THE NORTHWESTERN U.S. AND WESTERN
CANADA. THIS SETS THE STAGE FOR A PERIOD OF BELOW-AVERAGE COLD
THURSDAY THROUGH SUNDAY...THE FIRST MULTIPLE DAY STRETCH OF
BELOW AVERAGE TEMPERATURES FOR OUR AREA SINCE THE WEEK BEFORE
THANKSGIVING.
BY WEDNESDAY MORNING...THE OCCLUDED SURFACE LOW PRESSURE
ASSOCIATED WITH OUR NEAR TERM WINTER STORM WILL BE FILLING OVER
THE NORTHERN GREAT LAKES...WITH ITS TRAILING COLD FRONT EAST OF
THE FORECAST AREA. ANOTHER MID-LEVEL SHORT WAVE IS PROGGED TO
LIFT OUT OF THE LARGE WESTERN CONUS UPPER TROUGH DURING THE
MORNING...AND EVENTUALLY TAKING THE OLD SURFACE LOW OFF TO THE
NORTHEAST OF THE REGION. 00Z GFS/ECMWF AND GEM RUNS ARE ALL VERY
SIMILAR IN GENERATING AN AXIS OF LIGHT QPF BETWEEN 0.01-0.07"
ACROSS PARTS OF NORTH CENTRAL AND NORTHEAST ILLINOIS DURING THE
MORNING...MAINLY NORTHWEST OF THE I-55 CORRIDOR. USING A MODEL
BLEND QPF AND COBB OUTPUT SNOW/LIQUID RATIOS FROM ROUGHLY 11-13:1
ACROSS THE MAIN QPF AXIS DURING THE PERIOD...SUPPORTING A FEW
TENTHS OF AN INCH OF SNOW ACCUMULATION PERHAPS UP TO A HALF
INCH NORTHWEST OF THE CHICAGO AREA IN THE 12-18Z PERIOD. ONLY A
FEW FLURRIES PERHAPS LINGERING AT MIDDAY/EARLY AFTERNOON.
THE LONG WAVE UPPER TROUGH EVOLVES EASTWARD ACROSS CENTRAL NORTH
AMERICA WEDNESDAY NIGHT AND THURSDAY...EVENTUALLY BECOMING
ELONGATED IN A POSITIVE-TILT SOUTHWEST-NORTHEAST ORIENTATION BY
FRIDAY WITH THE TROUGH AXIS MOVING SOUTHEAST OF THE FORECAST
AREA. AT THE SURFACE...SURFACE LOW PRESSURE ASSOCIATED WITH
WEDNESDAYS DISTURBANCE PULLS AWAY TO THE EAST...WITH A BROAD
REGION OF COLDER WEST-NORTHEAST LOW LEVEL FLOW EAST OF STRONG
SURFACE HIGH PRESSURE DEVELOPING ACROSS THE NORTHERN AND
CENTRAL HIGH PLAINS. WHILE A FEW MINOR AMPLITUDE DISTURBANCES
APPEAR TO MOVE THROUGH THE FLOW ALOFT...LOW LEVELS ARE DOMINATED
BY COLDER...DRIER MODIFIED ARCTIC AIR AND LITTLE IN THE WAY OF
ORGANIZED PRECIP CHANCES ARE NOTED THROUGH THE WEEKEND. COLD
AIR...APPROACHING -10 TO -12 C AT 850 MB BY EARLY FRIDAY...
WILL LIKELY SUPPORT LAKE EFFECT SNOW SHOWERS DOWNWIND OF THE
LAKE ACROSS LOWER MICHIGAN. AS INDICATED ABOVE...THE PERIOD
FROM THURSDAY THROUGH SATURDAY LOOKS TO BE OUR FIRST MULTI-DAY
STRETCH OF BELOW AVERAGE TEMPS IN OVER A MONTH. MODEL LOW LEVEL
THERMAL PROGS AND GFS/ECMWF MOS NUMBERS DEPICT HIGHS IN THE 20S
THUR-FRI WITH LOWS IN THE TEENS AND EVEN A FEW SINGLE DIGITS
IN OUR TYPICALLY COLDEST SPOTS. AVERAGE TEMPS AROUND THE FIRST
OF THE YEAR ARE 30/14 AT ROCKFORD AND 31/17 FOR CHICAGO.
RATZER
&&
.HYDROLOGY...
A POWERFUL STORM SYSTEM WILL DRAW COPIOUS AMOUNTS OF MOISTURE
NORTHWARD ON MONDAY. SOME OF THE PRECIPITATION WILL FALL AS SLEET
AND FREEZING RAIN. TOTAL FORECAST LIQUID EQUIVALENT AMOUNTS ARE IN
THE 1 TO 1.5 INCH RANGE ACROSS NORTHERN AND CENTRAL ILLINOIS AND
NORTHWEST INDIANA. WITH SUCH ANOMALOUSLY HIGH MOISTURE
LEVELS...LOCALLY HIGHER TOTALS ARE PROBABLE. 24-HOUR RAIN AMOUNTS
FROM SATURDAY INTO SUNDAY MORNING WERE UP TO 2-3 INCHES SOUTH OF
THE KANKAKEE RIVER. THIS RAIN HAS ALREADY RESULTED IN RISES ON
RIVERS AND STREAMS IN THIS AREA. THE ADDITIONAL RAIN ON MONDAY
WILL EXACERBATE AND PROLONG ONGOING RISES. FOR AREAS FARTHER
NORTH...RIVER AND STREAM LEVELS ARE ALREADY RUNNING ABOVE
NORMAL...AND THE HEAVY FORECAST PRECIPITATION WILL RESULT IN
RENEWED RISES.
RC
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* MVFR CIGS CONTINUE THROUGH MID-LATE MORNING LOWERING TO IFR BY
LATE MORNING AND INTO LIFR THIS AFTERNOON.
* IFR VSBYS IN PRECIPITATION LATER THIS MORNING.
* NNE-NE WINDS WITH GUSTS 25-28 KT...VEERING E THIS MORNING WITH
GUSTS 30-35 KT...35-40 KT IN THE AFTERNOON.
* WINTRY MIX OF PCPN. FZRA HAS BEGUN SLIGHTLY EARLIER WITH VSBYS
INTERMITTENTLY DROPPING IN HEAVIER POCKETS. PCPN SHOULD
TRANSITION TO ALL LIQUID BY EARLY TO MID AFTERNOON.
* ISOLATED TSRA LATER THIS AFTERNOON.
KMD/MM
//DISCUSSION...UPDATED 12Z...
CONCERNS INITIALLY AROUND PRECIPITATION TYPE THIS MORNING. A MIXED
BAG IS BEING REPORTED AROUND THE AREA...WITH LIQUID PRECIPITATION
THE MAIN PRECIPITATION TYPE ALONG THE FAR SOUTHERN AREAS SOUTH OF
I-80 WHERE SURFACE TEMPERATURES ARE HOVERING RIGHT AROUND
FREEZING. ALONG THE I-80 TO I-90 CORRIDOR CLOSER TO CHICAGO P-TYPE
IS MAINLY SLEET...THEN A NOW SLEET MIX FARTHER NORTH AND WEST
TOWARD ROCKFORD AND WISCONSIN. EXPECT THAT AS THE WARM LAYER ALOFT
SPREADS NORTH THAT SLEET WILL TRANSITION TO FZRA/RA. MARGINAL
SURFACE TEMPERATURES SHOULD PRECLUDE A SIGNIFICANT ICE THREAT
CLOSER TO CHICAGO BUT ACCUMS REMAIN POSSIBLE...ESPECIALLY AS RATES
INCREASE AND SOME ADDITIONAL LOW LEVEL COOLING OCCURS. SLEET
ACCUMULATIONS HAVE OCCURRED AND WILL CONTINUE AT LEAST FOR A FEW
MORE HOURS. -SN/PL HANG ON LONGEST NORTHWEST...THEN A TRANSITION
TO RA THIS AFTERNOON. EVEN A TS CHANCE IN THE MID TO LATE
AFTERNOON.
OTHER CONCERN IS THE STRONG WINDS THAT WILL RAMP UP THIS MORNING
AND EVEN MORE SO THIS AFTERNOON. EXPECT GUSTS IN THE 30 KT RANGE
THEN TRANSITIONING TO POSSIBLY 40 KT THIS AFTERNOON...ESPECIALLY
CLOSER TO THE LAKE. CIGS WILL CONTINUE TO LOWER TO LOWER END
MVFR...THEN IFR AND EVEN LIFR LATER TODAY. VSBYS SHOULD LARGELY
HOLD MVFR FOR SOME TIME EXCEPT WEST IN THE HEAVIER PRECIPITATION
THAT IS SNOW AND AS PRECIP RATES INTENSIFY MID TO LATE MORNING.
WINDS SLACKEN TONIGHT AND TURN SOUTHWEST WITH PRECIP RATES
DECREASING...THOUGH THERE SHOULD BE A TRANSITIONING TO RA/SN MIX
OVERNIGHT.
KMD
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* MEDIUM TO HIGH CONFIDENCE IN GENERAL CIG TRENDS THOUGH MEDIUM ON
TRANSITION TIMES.
* HIGH IN OCCURRENCE OF IFR VSBYS AT TIMES BUT LOW ON THE LENGTH
OF TIME FOR LESS THAN 1SM VSBY.
* HIGH CONFIDENCE IN WIND TRENDS.
* HIGH CONFIDENCE IN MIXED/FREEZING PRECIP. MEDIUM HIGH CONFIDENCE
IN TIMING OF PCPN TYPE CHANGES.
* MEDIUM CONFIDENCE IN ISOLATED TS THIS AFTERNOON...BUT LOW
CONFIDENCE IN OCCURRENCE AT THE TERMINALS.
KMD/MM
//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...
TUESDAY NIGHT...VFR. SW WINDS.
WEDNESDAY...MVFR CIGS. CHANCE -SN OR -RASN EARLY WITH IFR
POSSIBLE. VFR/WX NIL LATE. SW WINDS.
THURSDAY...MVFR CIGS PSBL IN THE MORNING. W WINDS.
FRIDAY/SATURDAY...VFR/WX NIL. W WINDS.
SUNDAY...LAKE EFFECT SNOW SHOWERS PSBL MAINLY ALONG AND EAST OF
THE TERMINALS WITH MVFR CIGS. OTHERWISE VFR WITH NW WINDS.
KMD
&&
.MARINE...
416 AM CST
A STRONG PRESSURE GRADIENT BETWEEN ARCTIC HIGH PRESSURE IN
SOUTHERN ONTARIO AND DEEP LOW PRESSURE OVER THE ARKLATEX REGION
WILL STRENGTHEN TODAY AS THE LOW SHIFTS NORTHWARD THROUGH THE DAY
AND THE HIGH SHIFTS EASTWARD. GALE FORCE WINDS WILL INCREASE OVER
THE ENTIRE LAKE TODAY...WITH STORM FORCE WINDS EXPECTED FOR A
TIME THIS AFTERNOON AND EARLY EVENING ACROSS THE SOUTHERN HALF OF
THE LAKE.WITH A STRONG EAST FETCH...THESE WINDS LOOK TO AFFECT THE
ILLINOIS NEARSHORE AS WELL. THESE STRONG WINDS WILL RESULT IN
WAVES POSSIBLY REACHING NEAR 20 FT OVER THE SOUTH HALF OF THE
LAKE AND ILLINOIS NEARSHORE. THERE MAY BE A BRIEF PERIOD OF STORM
FORCE GUSTS THIS EVENING ACROSS THE NORTH...BUT HAVE HELD TO THE
GALE WARNING FOR THE NORTH HALF AS THE WINDOW APPEARS TO BE
SHORTER THAN FOR THE SOUTH HALF. THE LOW WILL PUSH NORTHEAST OVER
THE LAKE OVERNIGHT THEN NORTHEAST OF THE LAKE ON TUESDAY...AND
THIS WILL ALLOW WINDS AND WAVES TO SUBSIDE SIGNIFICANTLY AFTER
THIS POINT. MODERATE WESTERLY FLOW WILL CONTINUE OVER THE LAKE
FOR MUCH OF THE LATTER HALF OF THE WEEK.
KMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...LAKESHORE FLOOD WARNING...ILZ006-ILZ014 UNTIL MIDNIGHT TUESDAY.
WINTER STORM WARNING...ILZ013-ILZ014-ILZ021-ILZ022 UNTIL 3 PM
MONDAY.
HIGH WIND WARNING...ILZ006-ILZ014...1 PM MONDAY TO 7 PM MONDAY.
WINTER STORM WARNING...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ019-ILZ020 UNTIL 6 PM MONDAY.
WIND ADVISORY...ILZ013-ILZ021-ILZ022-ILZ023-ILZ032-ILZ033-ILZ039
UNTIL 6 PM MONDAY.
FLASH FLOOD WATCH...ILZ033-ILZ039 UNTIL 6 PM MONDAY.
FREEZING RAIN ADVISORY...ILZ033-ILZ039 UNTIL NOON MONDAY.
FREEZING RAIN ADVISORY...ILZ023-ILZ032 UNTIL 3 PM MONDAY.
IN...FREEZING RAIN ADVISORY...INZ001-INZ002 UNTIL 3 PM MONDAY.
WIND ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL 6 PM
MONDAY.
FLASH FLOOD WATCH...INZ010-INZ011-INZ019 UNTIL 6 PM MONDAY.
FREEZING RAIN ADVISORY...INZ010-INZ011-INZ019 UNTIL NOON MONDAY.
LM...STORM WARNING...ILLINOIS NEARSHORE WATERS UNTIL 9 PM MONDAY.
GALE WARNING...INDIANA NEARSHORE WATERS UNTIL 9 PM MONDAY.
STORM WARNING...LMZ777-LMZ779 UNTIL MIDNIGHT TUESDAY.
&&
$$
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AREA FORECAST DISCUSSION
NWS JACKSON KY
320 PM EST MON DEC 28 2015
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 245 PM EST MON DEC 28 2015
19Z SFC ANALYSIS SHOWS A VERY DEEP AREA OF LOW PRESSURE MOVING
INTO CENTRAL MISSOURI. THIS SYSTEM HAS A WARM FONT STRETCHED OUT
FROM ITS CENTER EAST THROUGH SOUTHERN KENTUCKY AND AN OCCLUDED/
COLD FRONT PUSHING EAST INTO SOUTHWEST KENTUCKY. THERE IS ALSO
QUITE A PRESSURE GRADIENT FROM THE LOW TO THE WEST AND HIGH
PRESSURE TO THE NORTHEAST. THIS IS GENERATING A PRETTY STRONG WIND
FIELD WITH GUSTS IN CENTRAL TENNESSEE AND SOUTH CENTRAL KENTUCKY
IN THE 30 TO 35 KT RANGE...AT TIMES. CLOSER TO HOME WINDS HAVE
BEEN A BIT TAMER...GENERALLY IN THE 15 TO 20 KT RANGE...THOUGH
PUSHING 30 KTS ABOVE 2000 FEET NEAR THE VIRGINIA BORDER. EXPECT
THE WINDS TO PICK UP THROUGH EASTERN KENTUCKY LATE THIS AFTERNOON
AND INTO THE EVENING AND AN SPS IS OUT ADDRESSING THAT CONCERN.
ALONG THE HIGHEST PEAKS NEAR THE VIRGINIA BORDER A MOUNTAIN WAVE
EVENT IS POSSIBLE WITH GUST TO 40 MPH ANTICIPATED...A WIND
ADVISORY CONTINUES FOR THESE COUNTIES. HOWEVER...GIVEN THE HIGHER
GUSTS SOUTH OF THE WARM FRONT AND JUST AHEAD OF THE COLD FRONT FOR
SOUTH CENTRAL KENTUCKY WILL FOLLOW SUIT WITH LMK AND ADD A
SOUTHERN TIER OF COUNTIES TO OUR CURRENT WIND ADVISORY WITH THIS
ISSUANCE.
THE WARM FRONT IS ONLY SLOWLY LIFTING THROUGH EASTERN KENTUCKY...
MAINTAINING COOL TEMPS TO ITS NORTH WHILE THE SOUTH SEES UPPER 60S
AND LOW 70S. DEWPOINTS SOUTH OF THE WARM FRONT ARE IN THE LOWER
60S WHILE TO THE NORTH THEY ARE CLOSE TO DRY BULB TEMPS. WIND TO
THE NORTH ARE FROM THE EAST AT 10 TO 15 MPH WITH OCCASIONAL GUSTS
TO 20 MPH. TO THE SOUTH OF THE WARM FRONT WINDS ARE SOUTHEAST TO
SOUTH AT SIMILAR SPEEDS. ON RADAR...A FEW LIGHT SHOWERS CONTINUE
TO DRIFT NORTH OVER EAST KENTUCKY AHEAD OF THE MAIN COLD FRONT/S
BAND OF HEAVIER SHOWERS. NO LIGHTNING HAS BEEN DETECTED WITH ANY
OF THE SHOWERS ALONG THE FRONT AS INSTABILITY REMAINS LOW. THIS
BAND IS WELL TIMED TO GET INTO EAST KENTUCKY LATE THIS AFTERNOON
AND INTO THE EARLY EVENING HOURS. DECENT RAINFALL RATES WITH THIS
BAND INITIALLY SUPPORTS THE FFA THAT IS OUT FOR OUR COUNTIES ALONG
AND WEST OF INTERSTATE 75.
THE MODELS ARE IN GOOD AGREEMENT ALOFT AT THIS LATE DATE WITH
THE MAIN FEATURE DRIVING OUR WEATHER FOR THE NEXT 24 TO 36
HOURS...THE DEEP CLOSED UPPER LOW LIFTING FROM THE SOUTHERN PLAINS
NORTH NORTHEAST INTO THE MID MISSISSIPPI VALLEY LATER TODAY AND TO
THE NORTHERN GREAT LAKES BY TUESDAY MORNING. THE BEST ENERGY WITH
THIS WILL PASS THROUGH KENTUCKY BY 06Z. IN ITS WAKE...HEIGHTS WILL
CLIMB AS THE SOUTHEAST RIDGE REASSERTS ITSELF. HOWEVER...ANOTHER
WEAKER AND SHALLOWER TROUGH WILL MOVE INTO THE SOUTHERN PLAINS
TUESDAY NIGHT AND STARTS TO IMPACT KENTUCKY BY DAWN WEDNESDAY.
GIVEN THE SOLID MODEL AGREEMENT HAVE FAVORED THE HIGHER RESOLUTION
NAM12 FOR WX DETAILS WITH A NOD TO THE HRRR IN THE NEAR TERM.
SENSIBLE WEATHER WILL FEATURE AN ACTIVE LATE AFTERNOON AND EVENING
OF WX WITH GUSTY WINDS AND POTENTIALLY EXCESSIVE RAINS AS THAT
COLD FRONT MOVES INTO THE AREA. A FLOOD WATCH...WIND ADVISORY...
AND SPS ARE IN EFFECT THROUGH THE EVENING FOR THIS DYNAMIC SYSTEM.
LOOK FOR TEMPERATURES TO TOP OUT IN THE EARLY EVENING AHEAD OF
THE HEAVIER SHOWERS FOR MOST PLACES THEN FALL BACK INTO THE 40S...
WEST...AND 50S...EAST...LATER TONIGHT AS THE SHOWERS TAPER OFF
FROM WEST TO EAST. TUESDAY WILL BE A QUIETER DAY WEATHER-WISE AS
THE SHOWERS EXIT TO EAST AND TEMPERATURES SETTLE TO NEAR 50
DEGREES IN THE EAST AND STAY IN THE MID AND UPPER 40S WEST...AS
CAA BEHIND THE FRONT BATTLES SOLAR INSOLATION. THIS WILL RESULT
IN A COOLER DAY THAN WE HAVE SEEN RECENTLY...BUT STILL MILDER
THAN NORMAL FOR THIS TIME OF YEAR.
A WEAK AREA OF LOW PRESSURE WILL LIFT ALONG THE COLD FRONT
STALLED TO THE SOUTH OF KENTUCKY TUESDAY NIGHT BRINGING A RENEWED
CHANCE FOR SHOWERS TO AT LEAST THE SOUTHEAST PART OF THE AREA
TOWARDS DAWN WEDNESDAY. THIS SHOULD BE THE LAST WAVE OF
SIGNIFICANT RAINFALL FOR THE CWA FOR A WHILE AND WILL CONTINUE TO
HIGHLIGHT IT IN THE ONGOING ESF. THIS WILL ALSO SERVE TO KEEP THE
TEMPERATURES MILD INTO WEDNESDAY MORNING WITH READINGS GENERALLY
IN THE LOW AND MID 40S EARLY THAT MORNING.
USED THE SHORTBLEND AS A STARTING POINT FOR TEMPERATURES AND DEW
POINTS THROUGH TUESDAY MORNING AND THE SUPERBLEND THEREAFTER
INTO TUESDAY NIGHT. DID HAVE TO ADJUST THESE RATHER SUBSTANTIALLY
IN THE NEAR TERM TO CAPTURE THE FRONTAL INDUCED TEMPERATURE
DIFFERENCES ACROSS THE CWA AND EXPECTED EVOLUTION INTO THE FIRST
PART OF THE EVENING. DID NOT MAKE MUCH ADJUSTMENT AFTER THAT AS
THE WINDS AND CLOUDS SHOULD KEEP READINGS RATHER UNIFORM
ELEVATION-WISE ACROSS EAST KENTUCKY TONIGHT AND TUESDAY NIGHT. AS
FOR POPS...ENDED UP ON THE HIGH SIDE OF A MOS BLEND THROUGH THE
PERIOD...BUT DEFINITELY FAVORING THE WETTER MET NUMBERS ON TUESDAY
NIGHT WITH THAT SOUTHEAST FRONTAL WAVE.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 320 PM EST MON DEC 28 2015
THE EXTENDED PERIOD WILL START OUT WET AND WARMER THAN NORMAL WITH
A WEATHER SYSTEM MOVING BY TO OUR SOUTHEAST AND EAST WEDNESDAY AND
WEDNESDAY NIGHT. THE WARM TEMPERATURES WILL BE THE RESULT OF
PERSISTENT SOUTHERLY TO SOUTHEASTERLY FLOW AHEAD OF AN
APPROACHING AREA OF LOW PRESSURE. NUMEROUS RAIN SHOWERS WILL
OVERSPREAD THE AREA AS THE SYSTEM MOVES BY TO OUR SOUTHEAST AND
MOISTURE WRAPS AROUND THE BACK SIDE OF IT. THE RAIN WILL GRADUALLY
TAPER OFF FROM WEST TO EAST WEDNESDAY NIGHT...AND SHOULD BE OUT OF
THE AREA BY AROUND 11Z ON THURSDAY. AFTER THE RAIN ENDS...A LARGE
AREA OF CANADIAN HIGH PRESSURE WILL SETTLE OVER THE REGION FOR THE
REST OF THE WEEK. THIS SYSTEM WILL BRING MUCH COOLER AIR TO THE
AREA...ALONG WITH NEAR NORMAL AND...AT TIMES...BELOW NORMAL
TEMPERATURES. HIGHS ON WEDNESDAY SHOULD BE ABLE TO REACH TO THE
MID TO UPPER 50S ACROSS EASTERN KENTUCKY IN THE SOUTHERLY FLOW.
WEDNESDAY NIGHT AND THURSDAY SHOULD SEE TEMPERATURES AROUND
NORMAL FOR THE TIME OF YEAR. FROM THURSDAY ONWARD...HOWEVER...ONCE
THE COLD AIR HAS SETTLED OVER US...WE WILL EXPERIENCE A PERIOD OF
BELOW NORMAL TEMPERATURES RIGHT ON THROUGH THE UPCOMING WEEKEND.
DAY TIME HIGHS FROM FRIDAY ONWARD WILL AVERAGE IN THE UPPER 30S
AND LOWER 40S FOR MOST LOCATIONS. OVERNIGHT LOWS DURING THIS TIME
WILL FALL INTO THE 20S. IN A NUTSHELL...THE EXTENDED PERIOD WILL
START OUT WET AND WARM WITH A GRADUAL TRANSITION TO DRY AND
SLIGHTLY COOLER THAN NORMAL WEATHER TO END THE WEEK AND INTO THE
WEEKEND.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 120 PM EST MON DEC 28 2015
SOME IFR AND BELOW CIGS REMAIN NORTH OF A WARM FRONT THAT ONLY
RECENTLY CLEARED SME AND LOZ ON ITS TRACK NORTH. AS THE FRONT
PASSES...CONDITIONS WILL IMPROVE FOR ALL SITES BEFORE THE
DETERIORATE AGAIN WITH THE APPROACH OF THE COLD FRONT IN THE EARLY
EVENING. WITH THIS...HAVE INCLUDED A BRIEF WINDOW FOR MVFR OR
LOWER VIS AND VCTS. THE CIGS WILL FURTHER LOWER DURING THE
OVERNIGHT HOURS AND LIKELY REMAIN IN THE IFR RANGE UNTIL AFTER
DAYBREAK ON TUESDAY. WINDS WILL BE MAINLY OUT OF THE EAST AND
SOUTHEAST AHEAD OF THE WARM FRONT BEFORE SWITCHING TO THE SOUTH
AND EVENTUALLY SOUTHWEST. WIND GUSTS TO THE 20 TO 25 KT RANGE WILL
BE POSSIBLE LATE THIS AFTERNOON INTO THE EVENING BEFORE SETTLING
SOME FOR THE REST OF THE NIGHT AND INTO TUESDAY.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 1 AM EST TUESDAY FOR KYZ087-088-118-120.
FLASH FLOOD WATCH UNTIL 10 PM EST THIS EVENING FOR KYZ068-079-
080-083>085.
&&
$$
SHORT TERM...GREIF
LONG TERM...AR
AVIATION...GREIF
AREA FORECAST DISCUSSION
NWS JACKSON KY
245 PM EST MON DEC 28 2015
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 245 PM EST MON DEC 28 2015
19Z SFC ANALYSIS SHOWS A VERY DEEP AREA OF LOW PRESSURE MOVING
INTO CENTRAL MISSOURI. THIS SYSTEM HAS A WARM FONT STRETCHED OUT
FROM ITS CENTER EAST THROUGH SOUTHERN KENTUCKY AND AN OCCLUDED/
COLD FRONT PUSHING EAST INTO SOUTHWEST KENTUCKY. THERE IS ALSO
QUITE A PRESSURE GRADIENT FROM THE LOW TO THE WEST AND HIGH
PRESSURE TO THE NORTHEAST. THIS IS GENERATING A PRETTY STRONG WIND
FIELD WITH GUSTS IN CENTRAL TENNESSEE AND SOUTH CENTRAL KENTUCKY
IN THE 30 TO 35 KT RANGE...AT TIMES. CLOSER TO HOME WINDS HAVE
BEEN A BIT TAMER...GENERALLY IN THE 15 TO 20 KT RANGE...THOUGH
PUSHING 30 KTS ABOVE 2000 FEET NEAR THE VIRGINIA BORDER. EXPECT
THE WINDS TO PICK UP THROUGH EASTERN KENTUCKY LATE THIS AFTERNOON
AND INTO THE EVENING AND AN SPS IS OUT ADDRESSING THAT CONCERN.
ALONG THE HIGHEST PEAKS NEAR THE VIRGINIA BORDER A MOUNTAIN WAVE
EVENT IS POSSIBLE WITH GUST TO 40 MPH ANTICIPATED...A WIND
ADVISORY CONTINUES FOR THESE COUNTIES. HOWEVER...GIVEN THE HIGHER
GUSTS SOUTH OF THE WARM FRONT AND JUST AHEAD OF THE COLD FRONT FOR
SOUTH CENTRAL KENTUCKY WILL FOLLOW SUIT WITH LMK AND ADD A
SOUTHERN TIER OF COUNTIES TO OUR CURRENT WIND ADVISORY WITH THIS
ISSUANCE.
THE WARM FRONT IS ONLY SLOWLY LIFTING THROUGH EASTERN KENTUCKY...
MAINTAINING COOL TEMPS TO ITS NORTH WHILE THE SOUTH SEES UPPER 60S
AND LOW 70S. DEWPOINTS SOUTH OF THE WARM FRONT ARE IN THE LOWER
60S WHILE TO THE NORTH THEY ARE CLOSE TO DRY BULB TEMPS. WIND TO
THE NORTH ARE FROM THE EAST AT 10 TO 15 MPH WITH OCCASIONAL GUSTS
TO 20 MPH. TO THE SOUTH OF THE WARM FRONT WINDS ARE SOUTHEAST TO
SOUTH AT SIMILAR SPEEDS. ON RADAR...A FEW LIGHT SHOWERS CONTINUE
TO DRIFT NORTH OVER EAST KENTUCKY AHEAD OF THE MAIN COLD FRONT/S
BAND OF HEAVIER SHOWERS. NO LIGHTNING HAS BEEN DETECTED WITH ANY
OF THE SHOWERS ALONG THE FRONT AS INSTABILITY REMAINS LOW. THIS
BAND IS WELL TIMED TO GET INTO EAST KENTUCKY LATE THIS AFTERNOON
AND INTO THE EARLY EVENING HOURS. DECENT RAINFALL RATES WITH THIS
BAND INITIALLY SUPPORTS THE FFA THAT IS OUT FOR OUR COUNTIES ALONG
AND WEST OF INTERSTATE 75.
THE MODELS ARE IN GOOD AGREEMENT ALOFT AT THIS LATE DATE WITH
THE MAIN FEATURE DRIVING OUR WEATHER FOR THE NEXT 24 TO 36
HOURS...THE DEEP CLOSED UPPER LOW LIFTING FROM THE SOUTHERN PLAINS
NORTH NORTHEAST INTO THE MID MISSISSIPPI VALLEY LATER TODAY AND TO
THE NORTHERN GREAT LAKES BY TUESDAY MORNING. THE BEST ENERGY WITH
THIS WILL PASS THROUGH KENTUCKY BY 06Z. IN ITS WAKE...HEIGHTS WILL
CLIMB AS THE SOUTHEAST RIDGE REASSERTS ITSELF. HOWEVER...ANOTHER
WEAKER AND SHALLOWER TROUGH WILL MOVE INTO THE SOUTHERN PLAINS
TUESDAY NIGHT AND STARTS TO IMPACT KENTUCKY BY DAWN WEDNESDAY.
GIVEN THE SOLID MODEL AGREEMENT HAVE FAVORED THE HIGHER RESOLUTION
NAM12 FOR WX DETAILS WITH A NOD TO THE HRRR IN THE NEAR TERM.
SENSIBLE WEATHER WILL FEATURE AN ACTIVE LATE AFTERNOON AND EVENING
OF WX WITH GUSTY WINDS AND POTENTIALLY EXCESSIVE RAINS AS THAT
COLD FRONT MOVES INTO THE AREA. A FLOOD WATCH...WIND ADVISORY...
AND SPS ARE IN EFFECT THROUGH THE EVENING FOR THIS DYNAMIC SYSTEM.
LOOK FOR TEMPERATURES TO TOP OUT IN THE EARLY EVENING AHEAD OF
THE HEAVIER SHOWERS FOR MOST PLACES THEN FALL BACK INTO THE 40S...
WEST...AND 50S...EAST...LATER TONIGHT AS THE SHOWERS TAPER OFF
FROM WEST TO EAST. TUESDAY WILL BE A QUIETER DAY WEATHER-WISE AS
THE SHOWERS EXIT TO EAST AND TEMPERATURES SETTLE TO NEAR 50
DEGREES IN THE EAST AND STAY IN THE MID AND UPPER 40S WEST...AS
CAA BEHIND THE FRONT BATTLES SOLAR INSOLATION. THIS WILL RESULT
IN A COOLER DAY THAN WE HAVE SEEN RECENTLY...BUT STILL MILDER
THAN NORMAL FOR THIS TIME OF YEAR.
A WEAK AREA OF LOW PRESSURE WILL LIFT ALONG THE COLD FRONT
STALLED TO THE SOUTH OF KENTUCKY TUESDAY NIGHT BRINGING A RENEWED
CHANCE FOR SHOWERS TO AT LEAST THE SOUTHEAST PART OF THE AREA
TOWARDS DAWN WEDNESDAY. THIS SHOULD BE THE LAST WAVE OF
SIGNIFICANT RAINFALL FOR THE CWA FOR A WHILE AND WILL CONTINUE TO
HIGHLIGHT IT IN THE ONGOING ESF. THIS WILL ALSO SERVE TO KEEP THE
TEMPERATURES MILD INTO WEDNESDAY MORNING WITH READINGS GENERALLY
IN THE LOW AND MID 40S EARLY THAT MORNING.
USED THE SHORTBLEND AS A STARTING POINT FOR TEMPERATURES AND DEW
POINTS THROUGH TUESDAY MORNING AND THE SUPERBLEND THEREAFTER
INTO TUESDAY NIGHT. DID HAVE TO ADJUST THESE RATHER SUBSTANTIALLY
IN THE NEAR TERM TO CAPTURE THE FRONTAL INDUCED TEMPERATURE
DIFFERENCES ACROSS THE CWA AND EXPECTED EVOLUTION INTO THE FIRST
PART OF THE EVENING. DID NOT MAKE MUCH ADJUSTMENT AFTER THAT AS
THE WINDS AND CLOUDS SHOULD KEEP READINGS RATHER UNIFORM
ELEVATION-WISE ACROSS EAST KENTUCKY TONIGHT AND TUESDAY NIGHT. AS
FOR POPS...ENDED UP ON THE HIGH SIDE OF A MOS BLEND THROUGH THE
PERIOD...BUT DEFINITELY FAVORING THE WETTER MET NUMBERS ON TUESDAY
NIGHT WITH THAT SOUTHEAST FRONTAL WAVE.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 502 AM EST MON DEC 28 2015
IN THE AFTERMATH OF THE STRONG SYSTEM THAT PULLED THROUGH DURING THE
SHORT TERM PERIOD...THE COLD FRONT WHICH PASSED THROUGH EASTERN KY
WILL BECOME STALLED OUT JUST EAST AND SOUTH OF THE REGION...WHILE
THE UPPER LEVEL LOW QUICKLY DISSOLVES TUESDAY NIGHT. IN ADDITION...
ANOTHER WEAK WAVE WILL PASS THROUGH EASTERN KY DURING THE DAY
WEDNESDAY...INTERACTING WITH THIS STATIONARY BOUNDARY. EXPECT THIS
TO PULL MOISTURE BACK INTO THE REGION FROM THE SOUTHEAST...AND ALLOW
YET ANOTHER ROUND OF SHOWERS TO AFFECT A GOOD PORTION OF EASTERN
KY...ESPECIALLY THE FAR SOUTHEAST. MODELS ARE ALL IN FAIRLY GOOD
AGREEMENT WITH THE PLACEMENT OF PRECIP INTO THE REGION STARTING
WEDNESDAY...PULLING OUT AS THE FRONTAL BOUNDARY SHIFTS EASTWARD ONCE
MORE WEDNESDAY NIGHT. ALL MODELS ARE ALSO FAVORING A MORE NORTHWARD
TRACK OF THIS SYSTEM...WHICH WAS REFLECTED IN THE LATEST POP
FORECAST...PUTTING AT LEAST CHANCE POPS ACROSS THE ENTIRE CWA AND
BETTER COVERAGE OF LIKELY TO WIDESPREAD POPS COMPARED TO PREVIOUS
FORECASTS.
AS HAS BEEN THE CASE OVER THE LAST WEEK...WILL NEED TO CLOSELY
MONITOR THIS SYSTEM AS IT COULD LEAD TO MORE FLOODING CONCERNS. AS
OF NOW...LOOKING AT AROUND A TENTH OF AN INCH TO A QUARTER OF AN
INCH ACROSS THE FAR WESTERN AND NORTHERN CWA...AND UP TO A HALF AN
INCH OR SLIGHTLY MORE IN THE FAR SOUTHEAST BETWEEN TUESDAY NIGHT AND
WEDNESDAY EVENING. IN ADDITION TO RECEIVING THE HEAVIEST RAINS...THE
STEEP TERRAIN IN THE FAR SOUTHEAST MAY ALSO LEND ITSELF TO BETTER
POTENTIAL FOR FLOODING.
THE FRONTAL BOUNDARY WILL REMAIN EAST OF THE REGION AS IT CONTINUES
TO LOSE STRENGTH FOR THE REMAINDER OF THE EXTENDED. A GENERAL
TROUGHING PATTERN OVER THE NORTH CENTRAL CONUS WILL LEAVE THE OHIO
RIVER VALLEY IN A STRONG SW TO NE FLOW ALOFT THURSDAY...WHILE
SURFACE HIGH PRESSURE WILL KEEP LLVL WINDS MORE W TO NW. THIS
TROUGHING PATTERN WILL SLOWLY RELAX THROUGH THE END OF THE WORK
WEEK...WITH MORE ZONAL FLOW TAKING HOLD ACROSS THE OHIO RIVER
VALLEY. AS SUCH...NO WAVES ARE FORECAST TO MOVE ACROSS THE
REGION...SO HAVE NO POPS IN AFTER 12Z THURSDAY.
ANOTHER UPPER LEVEL LOW OVER SOUTHEAST CANADA WILL BEGIN DIGGING
ACROSS THE EASTERN CONUS FRIDAY AND INTO THE WEEKEND. THIS WILL PULL
MUCH COOLER NORTHERN STREAM AIR SOUTHWARD INTO THE OHIO VALLEY
REGION...AND CONTINUE THE COOLING TREND ACROSS THE REGION. WITH
HIGHS ON WEDNESDAY EXPECTED TO BE IN THE 50S...ONLY UPPER 30S TO LOW
40S ARE EXPECTED BY SATURDAY AND SUNDAY AFTERNOONS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 120 PM EST MON DEC 28 2015
SOME IFR AND BELOW CIGS REMAIN NORTH OF A WARM FRONT THAT ONLY
RECENTLY CLEARED SME AND LOZ ON ITS TRACK NORTH. AS THE FRONT
PASSES...CONDITIONS WILL IMPROVE FOR ALL SITES BEFORE THE
DETERIORATE AGAIN WITH THE APPROACH OF THE COLD FRONT IN THE EARLY
EVENING. WITH THIS...HAVE INCLUDED A BRIEF WINDOW FOR MVFR OR
LOWER VIS AND VCTS. THE CIGS WILL FURTHER LOWER DURING THE
OVERNIGHT HOURS AND LIKELY REMAIN IN THE IFR RANGE UNTIL AFTER
DAYBREAK ON TUESDAY. WINDS WILL BE MAINLY OUT OF THE EAST AND
SOUTHEAST AHEAD OF THE WARM FRONT BEFORE SWITCHING TO THE SOUTH
AND EVENTUALLY SOUTHWEST. WIND GUSTS TO THE 20 TO 25 KT RANGE WILL
BE POSSIBLE LATE THIS AFTERNOON INTO THE EVENING BEFORE SETTLING
SOME FOR THE REST OF THE NIGHT AND INTO TUESDAY.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 1 AM EST TUESDAY FOR KYZ087-088-118-120.
FLASH FLOOD WATCH UNTIL 10 PM EST THIS EVENING FOR KYZ068-079-
080-083>085.
&&
$$
SHORT TERM...GREIF
LONG TERM...JMW
AVIATION...GREIF
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
305 PM EST MON DEC 28 2015
.SYNOPSIS...
A STORM SYSTEM TRACKING NORTHEAST THROUGH THE MIDWEST AND GREAT
LAKES WILL BRING A WINTRY MIX TO OUR AREA TONIGHT AND TUESDAY.
ANOTHER SYSTEM TRACKING NORTHEAST FROM THE GULF OF MEXICO WILL
BRING A CHANCE OF RAIN SHOWERS ON WEDNESDAY AND MILDER
TEMPERATURES BEFORE A RETURN TO COLDER TEMPERATURES BY THE END OF
THE WEEK.
&&
.NEAR TERM /THROUGH TUESDAY/...
RADAR SHOWS A WARM ADVECTION BAND OF A MIXED PRECIPITATION MOVING
EAST TOWARD NE PA AND FAR SW NY STATE AT THIS TIME. HEAVILY USED
THE HRRR FOR ONSET OF PRECIPITATION INTO THIS EVENING. ALSO
HEAVILY USED THE SPC SREF NCEP ALGORITHM FOR PTYPE WHICH LOOKS TO
BE DOING VERY WELL AND MATCHING THE MODEL SOUNDINGS DEPICTION OF
THE P-TYPE. BASICALLY EXPECT MAINLY SLEET AND A QUICK CHANGE-OVER
TO FZRA IN NE PA THIS EVENING WITH MORE SLEET FOR A LONGER PERIOD
OF TIME THIS EVENING INTO THE OVERNIGHT INTO C NY. MORE SNOW WILL
FALL AT FIRST IN NC NY. ALL THE PRECIP WILL TURN TO FREEZING RAIN
BY OVERNIGHT AND THEN TURN TO RAIN AND DRIZZLE TUESDAY FROM
SOUTHWEST TO NORTHEAST. LOOKS LIKE MAIN SLUG OF PRECIP COMES
THROUGH AROUND 06Z OR SO...WITH LIGHTER PRECIP TUESDAY. PRECIP
SHUD END AS DRIZZLE.
LOOKS LIKE SNOW WILL BE LESS IN NC NY THAN PREVIOUS FORECASTS
BASED ON SREF GUIDC AND WPC GUIDC AS WARM LAYER ARND 800 TO 700 MB
MAKES IT FAR TO THE N. NEW EURO AND CMC ALSO SHOW LESS
ACCUMULATED SNOW TOO WITH MAINLY 1-3 INCHES IN ONEIDA CO AND FAR
NRN ONONDAGA AND OTSEGO COUNTIES. MOST AREAS WILL SEE ARND .1 TO
.25 INCHES OF ICE WITH BETWEEN .25 AND .45 INCHES OF ICE PSBL
HIGHER TERRAIN CATSKILLS AND SW NY.
WITH GUSTY WINDS KICKING IN LATER TONIGHT AND TUESDAY AM THERE CUD
BE SOME MINOR POWER ISSUES WITH THE ICE ACCRETION.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
PRECIP WINDS DOWN COMPLETELY TUE NGT WITH A WESTERLY FLOW OF
COLDER AIR AND SOME DRIZZLE AND PATCHY FREEZING DRIZZLE AS CLOUD
DEPTHS ARE TOO SHALLOW FOR ICE CRYSTAL GROWTH.
THEN FOR WEDNESDAY...NEXT SYSTEM APPROACHES WITH ANOTHER SHOT OF
WARM AIR ADVECTION AND MAINLY RAIN...WHICH COULD BE MIXED WITH
SNOW NRN ONEIDA COUNTY. SOME MODELS SUGGEST ALL SNOW IN NRN
ONEIDA CO INTO WED NGT. FOR NOW HAVE RAIN OR SNOW UP THERE.
THEN FOR THURSDAY A COLDER WESTERLY FLOW OF AIR SETS UP WITH LAKE
EFFECT RAIN AND SNOW SHOWERS INTO CENTRAL AND NORTH CENTRAL NY. IT
SHUD STAY DRY IN NE PA.
&&
.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
2 PM MONDAY UPDATE...
FOR THE LONG TERM, IN THE BIG PICTURE FORECAST MODELS IN GOOD
OVERALL AGREEMENT SHOWING UPPER LEVEL TROUGHING OVER THE EAST WITH
RIDGING OVER THE WEST...A PATTERN WE REALLY HAVEN`T SEEN SO FAR
THIS SEASON. THIS WILL RESULT IN TEMPS AROUND AVERAGE WITH THE
MAIN WEATHER CONCERN BEING POTENTIAL FOR LAKE EFFECT SNOW. NO
MAJOR SYNOPTIC STORMS LOOK TO BE A THREAT THROUGH THE PERIOD. USED
SUPERBLEND TO INITIALIZE FORECAST WITH ONLY SOME MINOR ADJUSTMENTS
TO RAISE POPS FOR LAKE EFFECT.
IN TERMS OF DAY TO DAY WEATHER, TO START THE PERIOD WESTERLY FLOW
WITH COLD ADVECTION WILL RESULT IN LAKE EFFECT FOR THURSDAY NIGHT
INTO FRIDAY IN CENTRAL NY. WHILE IT`S EARLY TO GET SPECIFIC ON
DETAILS, BEST CHANCE FOR ANY SIGNIFICANT SNOW AT THIS POINT LOOKS
TO BE OVER NORTHERN ONEIDA COUNTY. HEADING INTO THE WEEKEND, LAKE
EFFECT SHOULD CONTINUE TO BE AN ISSUE WITH FLOW EVENTUALLY
BECOMING MORE NW WITH THE PASSAGE OF A COLD FRONT SHIFTING THE
BEST CHANCE FOR LAKE EFFECT FARTHER SOUTH TOWARD ONONDAGA AND
MADISON COUNTIES. GFS/EC/GEM ALL INDICATE HIGH PRESSURE EVENTUALLYMOVING
IN BY NEXT MONDAY BRINGING AN END TO MOST OF THE LAKE EFFECT WITH
FAIR WEATHER.
&&
.AVIATION /19Z MONDAY THROUGH SATURDAY/...
OTHER THAN SOME BRIEF RESIDUAL MVFR CEILINGS AT KITH/KELM,
UNRESTRICTED CONDITIONS EXPECTED THIS AFTERNOON.
A WINTRY MIX WILL DEVELOP THIS EVENING (01-04Z), THEN CONTINUE
OVERNIGHT. AT KSYR/KRME, PRECIPITATION SHOULD START AS SNOW, THEN
TRANSITION TO SLEET/FREEZING RAIN. AT KELM/KITH/KBGM/KAVP, ANY
INITIAL SNOW SHOULD BE VERY BRIEF, IF AT ALL, WITH SLEET/FREEZING
RAIN THE DOMINANT MODES OVERNIGHT INTO EARLY TUESDAY. IFR-LOWER
END MVFR CATEGORIES ARE FORESEEN.
STEADIER PRECIPITATION SHOULD END AS PATCHY LIGHT RAIN/DRIZZLE
MOST PLACES TUESDAY MORNING (12-15Z), AS SURFACE TEMPERATURES INCH
ABOVE FREEZING. CEILING BASES MAY DETERIORATE SOME AFTER DAYBREAK,
WITH IFR/BELOW ALT MIN CATEGORIES ANTICIPATED AREA-WIDE.
WINDS WILL ALSO BE A CONCERN STARTING THIS EVENING, AS THEY
INCREASE OUT OF THE SOUTHEAST, AND BECOME QUITE GUSTY OVERNIGHT.
GUSTS OF 25-35 KT ARE EXPECTED. WINDS WILL DIMINISH TUESDAY
MORNING.
.OUTLOOK...
TUE NGT INTO WED...RESTRICTIONS LIKELY IN LINGERING LOW
CLOUDINESS.
WED AFTN AND NIGHT...RESTRICTIONS LIKELY IN RAIN. RAIN MAY AT
LEAST START AS SNOW AT KRME.
THU-SAT...PERIODIC RESTRICTIONS IN SNOW SHOWERS FOR OUR CENTRAL
NY SITES, WITH MAINLY VFR AT KAVP.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...WINTER WEATHER ADVISORY FROM 8 PM THIS EVENING TO 1 PM EST
TUESDAY FOR PAZ039-040-048-072.
WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 10 AM EST
TUESDAY FOR PAZ038-043-044-047.
NY...WINTER WEATHER ADVISORY FROM 8 PM THIS EVENING TO 1 PM EST
TUESDAY FOR NYZ015>018-023-025-044-045-055>057-062.
WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 10 AM EST
TUESDAY FOR NYZ022-024.
WINTER WEATHER ADVISORY FROM 10 PM THIS EVENING TO 4 PM EST
TUESDAY FOR NYZ009-036-037-046.
&&
$$
SYNOPSIS...DJN
NEAR TERM...DJN
SHORT TERM...DJN
LONG TERM...PCF
AVIATION...MLJ
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
245 PM CST MON DEC 28 2015
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 245 PM CST MON DEC 28 2015
MAIN CHALLENGE IS IF WE WILL GET ANY PRECIP IN OUR SOUTH AND HOW
MUCH.
THE MAIN UPPER LOW IS CURRENTLY LIFTING THROUGH THE MID
MISSISSIPPI VALLEY AND IS CAUSING HAVOC TO OUR SOUTH AND EAST. A
SECONDARY UPPER CIRCULATION HAS DEVELOPED OVER NEBRASKA...AND THAT
WILL WEAKEN AND LIFT INTO EASTERN SD AND SOUTHERN MN OVERNIGHT.
THE MODELS HAVE BEEN IN MUCH BETTER AGREEMENT...BUT HAVE BEEN
TRENDING TOWARDS A DRIER SOLUTION FOR SOUTHEASTERN ND AND WEST
CENTRAL MN. THE MODELS ALL HAVE THE MAIN UPPER LOW WELL TO OUR
EAST...AND THE SECONDARY SYSTEM ONLY VERY SLOWLY MOVING INTO THE
NORTHERN PLAINS. THE SHORT RANGE AND GLOBAL MODELS ARE IN GOOD
AGREEMENT ON KEEPING PRECIP TO THE SOUTH OF OUR CWA BORDER.
LOWERED POPS AND SNOW AMOUNTS...MAINLY KEEPING A SMALL CHANCE IN
THE FAR SOUTH TO BLEND WITH NEIGHBORS AND IN THE INCREASINGLY
REMOTE CASE ONE OF THE OUTLIER MEMBERS OF THE SREF VERIFIES.
CLOUDS WILL BE INCREASING THOUGH AND SHOULD HELP KEEP TEMPS ABOVE
ZERO OVERNIGHT.
TOMORROW...THE SECONDARY UPPER SYSTEM CONTINUES TO SLOWLY MOVE
INTO SOUTHERN MN...AND THE MODELS ARE IN FAIRLY GOOD AGREEMENT ON
SOME VERY LIGHT PRECIP MOVING INTO OUR SOUTHERN COUNTIES DURING
THE AFTERNOON AND EVENING HOURS. THINK THERE SHOULD BE SOME
ACCUMULATIONS AROUND AN INCH OR SO...BUT OVER A 12 HOUR PERIOD.
OVERALL THE IMPACTS WILL REMAIN MOSTLY OUT OF OUR AREA AND WE
SHOULD BE CLOUDY WITH HIGHS IN THE TEENS FOR TUESDAY.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 245 PM CST MON DEC 28 2015
WEDNESDAY THROUGH THURSDAY...LARGE DIFFUSE UPPER TROUGH CONTINUES
OVER THE CENTRAL CONUS...WITH SIGNIFICANT EMBEDDED SHORTWAVES
STAYING MOSTLY TO OUR SOUTH. A FEW LINGERING FLURRIES IN THE SOUTH
FOR WEDNESDAY...BUT OTHERWISE THE PERIOD WILL REMAIN DRY. TEMPS
WILL BE JUST SLIGHTLY BELOW SEASONAL AVERAGES FOR HIGHS BUT CLOUDS
WILL KEEP THE LOWS MOSTLY ABOVE ZERO.
THURSDAY NIGHT THROUGH MONDAY...FOR THE LONG TERM...MODELS ARE
INDICATING THE REGION WILL BE UNDER NW FLOW ALOFT. BY
FRIDAY...TEMPS SHOULD BE ABOVE AVERAGE AS A SURFACE LOW WILL
EXIST OVER HUDSON BAY...AND HIGH PRESSURE OVER THE
CENTRAL/NORTHERN ROCKIES RESULTING IN WESTERLY LOW LEVEL FLOW. THE
GFS TRIES TO BRING A SHORT-LIVED PUSH OF COOL AIR TO THE REGION
SATURDAY NIGHT...BUT THE ECMWF KEEPS THIS WAVE AND THE COOL AIR
FURTHER EAST. HIGHS ARE EXPECTED TO BE IN THE 20S FOR FRIDAY
THROUGH MONDAY...WITH SOME 30S NOT OUT OF THE QUESTION. ALL IN
ALL...A QUIET PERIOD IS EXPECTED WITH WARMER CONDITIONS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1239 PM CST MON DEC 28 2015
MAIN CONCERN OVER THE NEXT 24 HOURS IS THE POTENTIAL FOR LOW CIGS.
KBJI CURRENTLY HAS MVFR CIGS AND BELIEVE THIS WILL CONTINUE AS
DEPICTED BY NAM MODEL AND, TO SOME EXTENT, THE GFS. THE HRRR HAS
BEEN VERY OPTIMISTIC WHEN IT COMES TO CIGS...BUT BASED ON LATEST
OBSERVATIONS...HAVE DISCOUNTED RECENT RUNS. BELIEVE LOW CIGS OVER
CENTRAL MN WILL EXPAND WESTWARD OVER THE NEXT 6 HRS...AND
POTENTIALLY BEYOND. HAVE MVFR CIGS MOVING INTO JUST KTVF IN A TEMPO
GROUP LATE THIS AFTERNOON...BUT THE POTENTIAL EXISTS FOR LOW CIGS
ALSO IN KFAR AND KGFK AS EARLY AS 00Z AS INDICATED BY NAM/GFS 925 MB
RH/NAM BUFR PROFILES. MAV AND MET GUIDANCE BOTH DO NOT HAVE LOW
CIGS. WILL HOLD OFF FOR NOW DUE TO HIGH UNCERTAINTY, HOWEVER. WILL
LOOK TO AMEND IF AFTERNOON TRENDS INDICATE THE NEED.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
SHORT TERM...JR
LONG TERM...JR/KNUTSVIG
AVIATION...KNUTSVIG
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1239 PM CST MON DEC 28 2015
.UPDATE...
ISSUED AT 1239 PM CST MON DEC 28 2015
MADE SOME TWEAKS TO THE CLOUDS...BUT NO OTHER MAJOR CHANGES TO THE
FIRST 6 HOURS OF THE FORECAST. LOWERED THE SNOW AMOUNTS A BIT FOR
TUESDAY AND WEDNESDAY AS THE BULK OF THE SYSTEM WILL BE TO OUR
SOUTH. WILL MAKE FURTHER REFINEMENTS THIS AFTERNOON.
UPDATE ISSUED AT 937 AM CST MON DEC 28 2015
TWEAKED CLOUD COVER A BIT...BUT AS TEMPS HAVE BEEN FASTER TO RISE
THAN THE PAST FEW MORNING WILL LEAVE HIGHS AS THEY ARE. EXPECT TO
SEE MOST READINGS BACK ABOVE ZERO BY THIS AFTERNOON.
THE 12Z NAM HAS COME IN...AND IS MORE IN AGREEMENT WITH THE GFS AS
FAR AS NOT MUCH SNOW IN OUR SOUTH FOR TONIGHT AND TOMORROW. WILL
WAIT TO SEE THE 12Z RUNS OF THE GFS AND ECMWF BEFORE MAKING
WHOLESALE CHANGES...BUT STARTED TO TREND DOWN A BIT ON QPF/SNOW
FOR TONIGHT. IF TRENDS CONTINUE IN A MORE EASTWARD DIRECTION...MAY
BE CUTTING SNOW AMOUNTS FURTHER IN FUTURE UPDATES.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY NIGHT)
ISSUED AT 400 AM CST MON DEC 28 2015
CONCERN WILL BE SNOW AMOUNTS ACROSS THE SOUTHERN FA. 00Z MODELS
HAVE COME INTO MUCH BETTER AGREEMENT THAN THE PAST FEW RUNS. THE
STRONG UPPER LOW ACROSS THE SOUTHERN CONUS WILL PROPAGATE N/NE
INTO THE GREAT LAKES REGION...WHILE A SECONDARY WEAKER UPPER LOW
(CURRENTLY NEAR WESTERN NEBRASKA) WILL SLOWLY PROPAGATE ACROSS
SOUTH DAKOTA INTO THE GREAT LAKES REGION. THIS SORT OF BRINGS TWO
DIFFERENT ROUNDS OF FORCING TO SE ND AND WC MN. THE TREND HAS BEEN
SOUTH WITH THE HEAVY (ADVISORY AND WARNING CRITERIA) SNOW WITH THE
FIRST ROUND...AND WEAKER WITH THE SECOND ROUND (ON
TUESDAY/TUESDAY NIGHT...ASSOCIATED WITH THE WEAKER UPPER LOW).
TRENDED THE FORECAST IN THIS DIRECTION...WITH POSSIBLY MORE CUTS
TO POPS AND SNOW AMOUNTS WITH FUTURE UPDATES.
.LONG TERM...(WEDNESDAY THROUGH SUNDAY)
ISSUED AT 400 AM CST MON DEC 28 2015
WEDNESDAY...HIGH PRESSURE WILL BEGIN BUILDING INTO THE
REGION...WITH ANY -SN OR FLURRIES WINDING DOWN. CLOUDS WILL LIKELY
REMAIN...WITH WHEN/IF THERE WILL BE ANY CLEARING THE MAIN
CHALLENGE.
THURSDAY-SUNDAY...SPLIT FLOW CONTINUES ACROSS NORTH AMERICA. LONG
WAVE RIDGE OVER WESTERN NORTH AMERICA BUILDS WHILE LONG WAVE
TROUGH AMPLIFIES OVER EASTERN NORTH AMERICA THROUGH THE PERIOD.
THE ECMWF BECOMES A FARTHER SOUTHERN SOLUTION THAN THE GFS AND THE
GFS BECOMES THE FASTER SOLUTION BY THE END OF THE PERIOD. LITTLE OR
NO PRECIPITATION IS EXPECTED THROUGH THE EXTENDED. WILL BLEND THE
ECMWF AND THE GFS.
HIGH TEMPERATURES WERE INCREASED ONE TO THREE DEGREES ON THU...AND
INCREASED ONE OR TWO DEGREES FOR FRI AND SAT. LITTLE CHANGE ON
SUN.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1239 PM CST MON DEC 28 2015
MAIN CONCERN OVER THE NEXT 24 HOURS IS THE POTENTIAL FOR LOW CIGS.
KBJI CURRENTLY HAS MVFR CIGS AND BELIEVE THIS WILL CONTINUE AS
DEPICTED BY NAM MODEL AND, TO SOME EXTENT, THE GFS. THE HRRR HAS
BEEN VERY OPTIMISTIC WHEN IT COMES TO CIGS...BUT BASED ON LATEST
OBSERVATIONS...HAVE DISCOUNTED RECENT RUNS. BELIEVE LOW CIGS OVER
CENTRAL MN WILL EXPAND WESTWARD OVER THE NEXT 6 HRS...AND
POTENTIALLY BEYOND. HAVE MVFR CIGS MOVING INTO JUST KTVF IN A TEMPO
GROUP LATE THIS AFTERNOON...BUT THE POTENTIAL EXISTS FOR LOW CIGS
ALSO IN KFAR AND KGFK AS EARLY AS 00Z AS INDICATED BY NAM/GFS 925 MB
RH/NAM BUFR PROFILES. MAV AND MET GUIDANCE BOTH DO NOT HAVE LOW
CIGS. WILL HOLD OFF FOR NOW DUE TO HIGH UNCERTAINTY, HOWEVER. WILL
LOOK TO AMEND IF AFTERNOON TRENDS INDICATE THE NEED.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...JR
SHORT TERM...TG
LONG TERM...TG/HOPPES
AVIATION...KNUTSVIG
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
1247 PM EST MON DEC 28 2015
.SYNOPSIS...
A WARM FRONT WILL BE LIFTING NORTH LATE TODAY AS LOW PRESSURE TRACKS
NORTH-NORTHEAST FROM ARKANSAS TO CENTRAL ILLINOIS. THIS LOW WILL
TRACK ACROSS SOUTHERN MICHIGAN AND INTO ONTARIO CANADA
TONIGHT...TAKING BOTH THE WARM AND COLD FRONTS ACROSS NORTHERN OHIO
AND NW PA. HIGH PRESSURE WILL BRIEFLY RESIDE ACROSS THE OHIO VALLEY
TUESDAY NIGHT. A FEW WEAK DISTURBANCES WILL BE MOVING ACROSS THE
GREAT LAKES FOR THE SECOND HALF OF THE WEEK WITH AN EXPANSIVE AREA
OF HIGH PRESSURE ACROSS THE MIDWEST AND THE LOWER OHIO VALLEY.
&&
.NEAR TERM /THROUGH TONIGHT/...
ONLY CHANGE WITH THIS FORECAST WAS TO EXPAND THE MENTION OF
FREEZING RAIN ACROSS THE CENTRAL HIGHLANDS INTO EARLY AFTERNOON.
AT THIS POINT IN TIME IT APPEARS THAT REGION WILL HAVE A CHANCE OF
FREEZING RAIN FOR THE NEXT COUPLE HOURS THAN TAPER OFF UNTIL THE
WARM FRONT GETS CLOSER. SINCE THE GROUND IS FAIRLY WARM HERE WILL
NOT EXPAND THE ADVISORY TO THIS REGION.
OTHERWISE ALL OTHER HEADLINES WILL REMAIN IN THEIR CURRENT
CONFIGURATIONS.
PREVIOUS DISCUSSION...
COMPLEX SYSTEM HEADED OUR WAY. THE DAY STARTS WITH HIGH PRESSURE SITTING
TO OUR NNW AND A COOL NNE FLOW ACROSS NRN OH/NW PA TO START.
PRECIPITATION CONCERNS HIGHEST AT OUR NW AND NE CORNERS...TOLEDO
AND NW PA.
FIRST ACROSS TOLEDO/NW OH FOR THE FIRST PART OF TODAY...HAVE PUT
UP A WINTER WEATHER ADVISORY FOR TODAY INTO EARLY EVENING. SURFACE
TEMPERATURES WILL BE HOVERING BETWEEN 30 AND 33 DEGREES
TODAY...NOT RISING UNTIL TONIGHT WHEN THE WARM FRONT LIFTS NORTH
AND STRONG SOUTHERLY WINDS BRING WARMER AIR NORTHWARD. EXPECT A
DROP IN TEMPS AS PRECIP STARTS...THEN HOLDING STEADY. BORDERLINE
CONDITIONS BETWEEN SLEET AND FREEZING RAIN. FURTHER TO OUR NORTH
COLD AIR IS DEEPER WITH SLEET MORE LIKELY. TOLEDO IS BORDERLINE.
OHDOT PAVEMENT TEMPS ARE READING AROUND 35 DEGREES...SO IMPACTS
SHOULD BE LESS. BIG QUESTION WILL BE WHEN DO TEMPS REALLY PUSH
ABOVE FREEZING. COULD THE STRONG EASTERLY FLOW OFF OF A LAKE IN
THE 40S BE ENOUGH TO WARM SURFACE TEMPS EARLY OR WILL WE HAVE TO
WAIT FOR THE SOUTHERLY FLOW? ONCE TEMPS GO UP THEY WILL CONTINUE
TO WARM INTO THE LOWER 40S FOR TONIGHT.
ACROSS NW PA...HAVE STARTED THE FREEZING RAIN ADVISORY
SOONER...STARTING IT AT NOON. LATEST HRRR WHICH HAS A GOOD HANDLE
ON CURRENT PICTURE HAS PRECIP MOVING IN FASTER THAN PREVIOUS
FORECAST. ANY PRECIP BEFORE NOON WOULD BE LIGHT. SIMILAR CONCERNS
WITH TEMPERATURES AND WHEN EXACTLY THEY WILL WARM ABOVE FREEZING.
HAVE MADE THAT TRANSITION EARLIER IN THE EVENING...ONLY HANGING ON
TO THE WINTRY PRECIPITATION ACROSS THE FAR EAST. IT IS POSSIBLE
THAT THE FZ RAIN ADV MAY BE ABLE TO END EARLY.
OTHERS MAY SEE SOME SPOTTY/PATCHES OF FREEZING RAIN FIRST THING
THIS MORNING WITH LITTLE OR NO IMPACT. TEMPS MAY BE HARD PRESSED
TO GET MUCH BELOW 32.
RAINFALL AMOUNTS ARE EXPECTED TO BE AROUND A HALF INCH. LOCALLY
HEAVIER AMOUNTS ARE POSSIBLE ESPECIALLY IF WE GET THUNDER UP INTO
THE AREA. HAVE NOT INCLUDED THE THUNDER YET IN THE FORECAST. HAVE
HIGHLIGHTED THE RAINFALL AND POSSIBLE MINOR FLOODING IN THE
HAZARDOUS WEATHER OUTLOOK. AREA CREEKS AND STREAMS WILL CONTINUE
TO RUN HIGH...WITH SOME OF OUR RIVER FORECAST POINTS REACHING INTO
MINOR FLOOD. IF RAINFALL FORECAST NEEDS TO BE INCREASED THEN A
FLOOD WATCH WILL BE NEEDED. RAIN WILL LESSEN DURING THE OVERNIGHT
HOURS...BUT LINGER WITH MOIST CYCLONIC FLOW.
WILL HAVE AN OUTRIGHT STIFF EASTERLY WIND PICK UP FOR THIS
AFTERNOON...COMING AROUND TO THE SE AND SOUTH BY TONIGHT. FOR NOW
HAVE A WIND ADVISORY FOR ERIE COUNTY PA WITH THE ENHANCED
DOWNSLOPE. OTHERS...FOR NOW...WILL HAVE GUSTS OF 35 TO 45 MPH.
TEMPS WILL RISE TONIGHT INTO THE LOWER AND MID 40S. WE MAY EVEN
SEE A 50 OR TWO.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
THE PERSISTENT SOUTHEAST RIDGE WILL BEGIN TO BREAK DOWN THROUGH
THE COURSE OF THE WEEK. NOT A LOT OF COLD AIR BEHIND MONDAY`S
SYSTEM....BUT LOW LEVEL MOISTURE WILL LINGER AND THEREFORE THE
CLOUDS TOO. ANY REMAINING LIGHT RAIN WILL TAPER OFF DURING THE DAY
TUESDAY. A WEAK DISTURBANCE WEDNESDAY WILL GIVE US ANOTHER CHANCE
FOR LIGHT RAIN...WITH SNOW SHOWERS POSSIBLE LATE WEDNESDAY NIGHT
AS THE COLDER AIR FILTERS INTO THE REGION. MID 40S TUESDAY AND
LOWER 40S FOR HIGHS WEDNESDAY. WIDESPREAD TEMPS BELOW FREEZING
WEDNESDAY NIGHT.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
NOT MANY CHANGES AGAIN TODAY AS A MORE WINTRY PATTERN GETS
ESTABLISHED. IT LOOKS LIKE WE WILL SEE SEVERAL DAYS WITH LAKE
EFFECT SNOW POTENTIAL. THE 00Z ECMWF IS A LITTLE QUICKER BRINGING
IN THE COLDER AIR ALOFT ON THURSDAY. THE LAKE EFFECT WILL GET GOING
LATE IN THE DAY AND WILL STICK WITH LIKELY POPS THURSDAY NIGHT.
GIVEN A 260 TO 270 DEGREE FLOW THE SNOW WILL NOT SPREAD VERY FAR
INLAND ACROSS NE OHIO. SOME ACTIVITY IS EXPECTED ON FRIDAY AS WELL.
SATURDAY WILL SEE SOME WEAK WARM AIR ADVECTION WHICH MAY CAUSE THE
PRECIP ACTIVITY TO DIMINISH SOME. A REINFORCING SHOT OF COLD AIR
WILL ARRIVE SATURDAY NIGHT INTO SUNDAY BEHIND ANOTHER TROUGH. WILL
SEE PRECIP CHANCES RAMP UP AGAIN AT THAT TIME. AREAS AWAY FROM THE
SNOWBELT WILL SEE LITTLE MORE THAN A FEW FLURRIES DURING THE PERIOD.
THERE SHOULD BE A FAIR AMOUNT OF CLOUDINESS. TEMPS WILL BE NEAR
NORMAL WITH HIGHS MAINLY IN THE LOW TO MID 30S.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
SURGES OF RAIN WILL CONTINUE TO MOVE NORTH WITH THE WARM FRONT AND
A GUSTY EAST WIND. OCCASIONAL FREEZING RAIN AND A LITTLE SLEET
WILL PERSIST UNTIL THE WARM FRONT MOVES NORTH OF THE AREA THIS
EVENING. CEILINGS WILL CONTINUE TO LOWER AND MOST SITES WILL
BECOME IFR. WINDS WILL BECOME SOUTHEAST WITH THE PASSAGE OF THE
WARM FRONT. THE COLD FRONT WILL SWING THROUGH LATER TONIGHT. WINDS
WILL VEER TO SOUTHWEST AND CEILINGS SHOULD IMPROVE TO MVFR AS
DRIER AIR BEGINS TO FILTER IN. MVFR CEILINGS AND GUSTY SOUTHWEST
WINDS WILL CONTINUE ON TUESDAY.
OUTLOOK...NON VFR CONDITIONS LIKELY AGAIN WEDNESDAY EVENING INTO
THURSDAY. NON VFR LINGERING IN THE SNOWBELT OF EXTREME NE OH/NW
PA FRIDAY INTO SATURDAY.
&&
.MARINE...
WILL GO AHEAD AND UPGRADE THE GALE WATCH TO A WARNING FOR
THE WEST HALF OF THE LAKE. DO NOT THINK WE WILL GET SUSTAINED GALES
SO THIS WILL BE A MARGINAL EVENT AND WILL HAVE TO RELY ON THE
FREQUENT GUST CRITERIA. IT APPEARS WATER LEVELS IN THE WEST BASIN
WILL STAY ABOUT A FOOT BELOW LAKESHORE FLOOD WARNING LEVELS.
FORTUNATELY THE NE TO E FETCH WON`T BE PROLONGED WITH SE FLOW
DEVELOPING THIS EVENING. HAVE GONE AHEAD AND EXTENDED THE SMALL
CRAFT IN THE EAST THROUGH TOMORROW. EXPECT THE FLOW TO EVENTUALLY
BECOME SW ON TUESDAY BEHIND THE COLD FRONT. SW TO W FLOW WILL THEN
CONTINUE THROUGH THE END OF THE WEEK. WILL LIKELY NEED SMALL CRAFT
HEADLINES MUCH OF THE WEEK.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR OHZ003-
006.
PA...WIND ADVISORY FROM 10 PM THIS EVENING TO 7 AM EST TUESDAY FOR
PAZ001-002.
FREEZING RAIN ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR PAZ002-
003.
MARINE...GALE WARNING UNTIL 10 PM EST THIS EVENING FOR LEZ142>146-
162>166.
SMALL CRAFT ADVISORY UNTIL 10 PM EST TUESDAY FOR LEZ147>149.
&&
$$
SYNOPSIS...OUDEMAN
NEAR TERM...MULLEN/OUDEMAN
SHORT TERM...OUDEMAN
LONG TERM...KUBINA
AVIATION...KOSARIK
MARINE...KUBINA
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1137 AM CST MON DEC 28 2015
.SHORT TERM...(TODAY THROUGH TUESDAY AFTERNOON)
ISSUED AT 339 AM CST MON DEC 28 2015
MODELS SEEMS TO HAVE CONVERGED TOWARDS AN AGREEABLE SOLN THIS
MORNING...PIVOTING THE UPPER LOW THROUGH EASTERN MISSOURI AND INTO
NORTHERN MICHIGAN BY TUESDAY MORNING. THIS MARKS A SLIGHTLY MORE
EASTWARD TRAJECTORY THAN PREVIOUSLY ADVERTISED...LIKELY DUE TO SOME
IMPACT FROM CONVECTION ASSOCIATED WITH THE WAVE. THE OVERALL
CONSENSUS PLACES THE TRACK OF THIS WAVE SLIGHTLY FURTHER WEST THAN
THE GFS/NAM...AND MORE ALONG THE LINE OF THE ECMWF/GEM.
PRECIPITATION ALREADY ONGOING OVER THE LOWER MO RIVER VALLEY WILL
CONTINUE TO PRESS NORTHWARD TOWARDS THE CWA BY MID-MORNING.
STRONG DIVERGENCE ALOFT COMBINED WITH BROAD BUT INTENSE LOW LEVEL
WARM ADVECTION SHOULD SEND A BROAD AREA OF LIGHT TO MODERATE SNOWS
NORTHWARD THROUGH THE DAY. HRRR SUGGESTS INITIAL BANDS REACH SIOUX
CITY AND STORM LAKE BY 8AM...THE I-90 CORRIDOR BY NOON...AND THE
NORTHERN CWA AFTER MID-AFTERNOON.
MODELS ALSO GRASPING SLIGHTLY BETTER AT WEAKER PV ANOMALY OVER
NORTHERN KANSAS AND SOUTH CENTRAL NEBRASKA. THIS WAVE WILL PIVOT
NORTHEAST WITH THE STRONGER EASTERN LOW BY MONDAY NIGHT...AND
CONTINUES TO SHOW SIGNS OF INTENSIFICATION GIVEN NICE JET STREAK
ALOFT. I DO HAVE SOME CONCERNS ABOUT THE IMPACT OF A DRY INTRUSION
OF AIR WITH THE 700:600 MB LAYER ADVERTISED BY THE NAM ARRIVING FROM
THE SOUTHWEST THIS AFTERNOON. THIS HAS POTENTIAL TO REALLY LIMIT
SNOWFALL RATES DURING THE SECOND HALF OF THE AFTERNOON.
MOVING AHEAD...THIS SECONDARY PV ANOMALY MAY LINGER JUST NORTH OF
THE TRI-STATE AREA WELL INTO TUESDAY AND GIVEN UPR DYNAMICS...SHOULD
SUPPORT A LONGER DURATION SNOWFALL OVER THE NORTHERN AND
NORTHEASTERN CWA INTO TUESDAY AFTERNOON.
WHILE QPF AMOUNTS HAVE TRENDED DOWNWARD...SLR VALUES HAVE
TRENDED UPWARDS SLIGHTLY. INITIAL ONSET OF PRECIPITATION MAY SEE 12-
13:1 RATIOS WITH VALUES INCREASING TOWARDS THE 14-15:1 RATIO THROUGH
THE NIGHT. THESE VALUES PUSH THE HIGHEST SNOWFALL TOTALS OVER THE
FAR EASTERN CWA...WITH THE HIGHEST CONCENTRATION OF 6 INCH OR HIGHER
REPORTS OVER MINNESOTA/IOWA COUNTIES. ELSEWHERE...A LONGER DURATION
2 TO 6 INCH SNOWFALL SEEMS LIKELY.
AS FAR AS HEADLINES ARE CONCERNED...WILL PUSH WARNING SLIGHTLY
FURTHER NORTH INTO THE MARSHALL AREA GIVEN POTENTIAL OF 6 - 8 INCHES
OVER 24 HOURS AND IMPACTS FROM WINDS. WILL ALSO ISSUE AN ADVISORY
FOR THE REMAINING AREAS ALONG AND WEST OF I-29. WHILE SNOWFALL
TOTALS ARE SLIGHTLY LOWER...THROUGH COLLABORATION...WILL LEAVE
WARNING IN PLACE FOR NERN NEBRASKA AND FAR SOUTHEASTERN SD COUNTIES.
.LONG TERM...(TUESDAY EVENING THROUGH SUNDAY)
ISSUED AT 339 AM CST MON DEC 28 2015
SNOW WILL BE LIGHT AND BECOMING SPOTTY BY TUESDAY EVENING AND BE
CONCENTRATED IN THE NORTHERN PART OF OUR FORECAST AREA. IN FACT...IT
MAY QUICKLY WEAKEN TO SCATTERED FLURRIES. WILL STILL CARRY THE
LOW...MOSTLY SLIGHT CHANCE POPS...WE HAVE BEEN GOING WITH IN THE
FLAT UPPER FLOW BEHIND THE MAIN SYSTEM. ANY LINGERING FLAKES SHOULD
END WEDNESDAY. AMOUNTS IF ANY WILL BE A HALF INCH OR LESS. LOW
LEVEL.SURFACE FLOW AND WINDS WILL BE NORTHWESTERLY AND SHOULD BE
FAIRLY LIGHT. EXPECT PLENTY OF CLOUDS TO REMAIN THROUGH WEDNESDAY.
TEMPERATURES FOR THE TIME WILL SHOW A SMALL DIURNAL RANGE WITH ABOVE
NORMAL LOWS AND BELOW NORMAL HIGHS.
A DRYING PROCESS IS EXPECTED TO ACCOMPANY A GRADUALLY DEVELOPING
NORTHWESTERLY FLOW ALOFT AND AT THE SURFACE STARTING WEDNESDAY NIGHT
AND THURSDAY. THIS DRY TREND SHOULD CONTINUE THROUGH THE WEEKEND.
TEMPERATURES WILL WARM SOME ON HIGHS WITH THE WARMING TREND OF
COURSE MODIFIED BY SNOW COVER. LOWS SHOULD STAY THE SAME
OR COOL A BIT. WILL GO WITH THE EXTENDED GUIDANCE TEMPERATURES FOR
NOW BUT THINK THEY COULD BE UNDER DOING THE DIURNAL RANGES...
MAINLY ON FORECAST LOWS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1133 AM CST MON DEC 28 2015
IFR CONDITIONS OR LOWER ARE EXPECTED ALONG AND EAST OF I-29 AS A
STRONG UPPER LEVEL LOW PRESSURE SYSTEM MOVES INTO THE UPPER
MIDWEST. NORTHEAST WINDS WILL BREEZY AT THE ONSET OF THE
PERIOD...BUT WILL GRADUALLY SHIFT TO THE NORTHWEST AND DECREASE IN
INTENSITY. THE HEAVIEST SNOW WILL FALL EAST OF HIGHWAY 60 ACROSS
NORTHWEST IOWA INTO SOUTHWEST MINNESOTA.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...WINTER WEATHER ADVISORY UNTIL NOON CST TUESDAY FOR SDZ060>069.
WINTER STORM WARNING UNTIL 9 AM CST TUESDAY FOR SDZ070-071.
WINTER WEATHER ADVISORY UNTIL 6 PM CST TUESDAY FOR SDZ040-055-
056.
WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 6 PM CST
TUESDAY FOR SDZ038-039-052>054-057>059.
MN...WINTER WEATHER ADVISORY UNTIL 6 PM CST TUESDAY FOR MNZ071.
WINTER STORM WARNING UNTIL 6 PM CST TUESDAY FOR MNZ072-080-081-
089-090-097-098.
IA...WINTER STORM WARNING UNTIL 9 AM CST TUESDAY FOR IAZ001>003-
012>014-020>022-031-032.
NE...WINTER STORM WARNING UNTIL 9 AM CST TUESDAY FOR NEZ013-014.
&&
$$
SHORT TERM...DUX
LONG TERM...
AVIATION...
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1133 AM CST MON DEC 28 2015
.AVIATION...
AREA OF MVFR CEILINGS WILL LIKELY SKIRT THE HOUSTON METRO AIRPORTS
THROUGH THE AFTERNOON AND IMPACT THE SITES TO THE NORTH THROUGH
THIS EVENING. THE HRRR AND NAM12 BOTH GIVE THE OUTSIDE POSSIBILITY
OF MVFR CEILINGS AS FAR TO THE SOUTH AS KSGR AND KLBX DURING THE
AFTERNOON. HOWEVER...THINK THAT THE TRENDS ARE BETTER FOR VFR
TOWARD THE COAST AND POINTS SOUTH OF HOUSTON. WINDS WILL DIMINISH
DURING THE LATE AFTERNOON TO EARLY EVENING PERIOD AS HIGH PRESSURE
BUILDS INTO THE AREA. AS THE HIGH MOVES OFF TO THE EAST...THE HINT
OF EASTERLY OR SOUTHEASTERLY WINDS WILL RETURN BY LATE MORNING
TUESDAY.
40
&&
.PREV DISCUSSION... /ISSUED 945 AM CST MON DEC 28 2015/
UPDATE...
OTHER THAN A FEW TWEAKS TO ACCOUNT FOR OBSERVATIONS THIS
MORNING...THE FORECAST WAS LEFT UNCHANGED FOR TODAY. STILL
LOOKING FOR A COOL AFTERNOON WITH BRISK WNW WINDS GRADUALLY
LESSENING LATER TODAY AS THE STACKED LOW SYSTEM CONTINUES TO LIFT
AWAY FROM SERN TX.
48
PREV DISCUSSION... /ISSUED 354 AM CST MON DEC 28 2015/
DISCUSSION...
AT 1 AM...AN AREA OF LOW PRESSURE WAS LOCATED OVER NORTHERN
LOUISIANA WITH A COLD FRONT EXTENDING FROM THE LOW ACROSS THE
WESTERN GULF. STRONG WEST WINDS ON THE BACKSIDE OF THE LOW WILL
GRADUALLY DIMINISH THIS MORNING. PRECIP FOR THE MOST PART HAS COME
TO AN END BUT WITH A DRY SLOT SURGING INTO SE TX. SATELLITE
IMAGERY SHOWS CLOUDS WRAPPING AROUND THE THE LARGE UPPER LOW OVER
NE TX AND AM EXPECTING CLOUDS TO FILL BACK IN DURING THE MORNING
WITH MOSTLY CLOUDY SKIES PREVAILING TODAY...ESPECIALLY NORTH OF
I-10. WILL LET THE WIND ADVISORY EXPIRE AT 12Z. PROBABLY STILL GET
SOME GUSTS NEAR 30 KNOTS BUT PREVAILING WINDS SHOULD BE WELL BELOW
ADVISORY CRITERIA. CLOUDS AND CONTINUED COLD AIR ADVECTION WILL
KEEP MAX TEMPS BELOW CLIMO TODAY AND TEMPS MAY STRUGGLE TO REACH
50 DEGREES. CLOUDS WILL CLEAR OUT EARLY THIS EVENING ONLY TO BE
REPLACED BY A CIRRUS CANOPY. 850 TEMPS BEGIN TO WARM AND MAX TEMPS
ON TUESDAY WILL BE WARMER THAN TODAY AND WILL PROBABLY TOP OUT IN
THE UPPER 50S. CLOUD COVER WILL ALSO BE ON THE INCREASE IN
RESPONSE TO A S/WV MOVING EAST INTO THE SOUTHERN PLAINS AND BRISK
WARM AIR ADVECTION AT 850 MB. ECMWF/GFS DIFFER WITH REGARD TO
AVAILABLE MSTR ON TUE NIGHT/EARLY WEDS WITH THE ECMWF MORE MOIST
AND MORE GENEROUS WITH QPF. THE CANADIAN SUPPORTS THE WETTER ECMWF
AND THE TEXAS TECH WRF ALSO SHOWING SOME LIGHT RAIN TUES NIGHT
BUT RAPID DRYING BY WED MORNING. WILL MAINTAIN 20/30 POPS FOR TUE
NIGHT INTO EARLY WEDS. WEDNESDAY LOOKS LIKE THE NICE DAY OF THE
WEEK WITH MAX TEMPS IN THE LOWER 60S AND A LITTLE MORE SUNSHINE. A
SURGE OF HIGH PRESSURE WILL BUILD INTO SE TEXAS WED NIGHT AND
THURSDAY BRING COOLER CONDITIONS. THE ECMWF AND GFS DIFFER
SIGNIFICANTLY ON FRIDAY AS THE GFS SHOWS A FAVORABLE PATTERN FOR
ISENTROPIC UPGLIDE...CLOUDS AND PERIODS OF LIGHT RAIN. THE ECMWF
PATTERN IS LESS FAVORABLE FOR UPGLIDE AND CONSIDERABLY DRIER. THE
CANADIAN FAVORS THE WETTER GFS SO HAVE LEANED TOWARD THE WETTER
GFS SOLUTION. LOW CONFIDENCE IN EITHER SOLUTION ATTM. 43
MARINE...
STRONG COLD ADVECTION EARLY THIS MORNING WILL WARRANT A SLIGHT
EXTENSION FOR THE GALE WARNING IN THE FAR OFFSHORE WATERS WHERE
WINDS HAVE BEEN GUSTING AOA 40 KNOTS WITH IMPRESSIVE 14 FT SEAS AT
42019. WINDS SHOULD RELAX LATE THIS MORNING THROUGH THE EVENING
HOURS AS HIGH PRESSURE OVER RIO GRANDE MOVES EAST AND NORTHEAST
WHICH WILL TURN WINDS FROM WEST TO THE NORTHEAST AT 5-10KTS BY
TONIGHT FOR THE BAYS AND NEARSHORE WATERS. NEXT ISSUE IS THE ABRUPT
RETURN OF A WARM FRONT LATE TUESDAY. LLJ SURGES BACK NORTH TUESDAY
AND WILL RAPIDLY BRING BACK THE CLOUDS AND UPGLIDE TO THE UPPER
TEXAS COASTAL WATERS AS WELL AS VEER WINDS TO THE EAST. EXPECT TO
SEE RAIN AND SHOWERS AND COULD SEE A FEW THUNDERSTORMS LATE
TUESDAY/EARLY WEDNESDAY MORNING BEFORE THE NEXT COLD FRONT ARRIVES.
CAA AND NORTHERLY FLOW WILL DOMINATE THE WIND FIELDS OVER THE UPPER
TEXAS COASTAL WATERS WEDNESDAY THROUGH SUNDAY AS A 1035MB HIGH
PRESSURE SYSTEM PARKS OVER WEST TEXAS AND SLOWLY WEAKENS OVER THE
WEEKEND. SCEC/SCA MAY RETURN WEDNESDAY AND THURSDAY AND MORE LIKELY
FRIDAY AND SATURDAY FOR THE MODERATE OFFSHORE FLOW.
45
CLIMATE...
THERE WERE MANY MEMORABLE BIG RAIN EVENTS THIS YEAR ACROSS SE TX
WITH MANY LOCATIONS RECORDING THEIR WETTEST YEAR ON RECORD...
INCLUDING THE CITIES OF BAYTOWN AND BRENHAM. THE RAINFALL FROM
YESTERDAY INCREASED THE 2015 ANNUAL TOTALS ABOVE 70 INCHES FOR THE
CITY OF HOUSTON. HERE ARE THE UPDATED 2015 TOTALS:
CITY OF CITY OF HOUSTON COLLEGE
HOUSTON GALVESTON HOBBY STATION
72.86 1900 78.39 1900 83.02 1979 61.04 1968
72.38 1919 70.59 1941 82.14 1981 59.91 1973
71.19 2001 67.21 1946 81.68 2001 58.22 2015
70.16 1973 66.88 1877 80.59 1973 57.62 1991
70.01 2015 65.88 1888 77.12 2015 57.44 1994
61.52 2015 # 13
43
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 48 36 57 44 58 / 10 10 10 20 10
HOUSTON (IAH) 51 38 58 47 61 / 10 10 10 30 20
GALVESTON (GLS) 52 46 60 54 62 / 10 10 10 40 20
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT ADVISORY UNTIL NOON CST TODAY FOR THE FOLLOWING
ZONES: GALVESTON BAY...MATAGORDA BAY...WATERS FROM FREEPORT
TO THE MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS FROM HIGH
ISLAND TO FREEPORT OUT 20 NM.
SMALL CRAFT ADVISORY UNTIL 6 PM CST THIS EVENING FOR THE
FOLLOWING ZONES: WATERS FROM FREEPORT TO THE MATAGORDA SHIP
CHANNEL 20 NM TO 60 NM...WATERS FROM HIGH ISLAND TO
FREEPORT 20 TO 60 NM.
&&
$$
DISCUSSION...14
AVIATION/MARINE...40
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE
.SHORT TERM...TONIGHT AND TUESDAY
ISSUED AT 224 PM CST MON DEC 28 2015
THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A STRONG
LOW PRESSURE SYSTEM MOVING NORTH-NORTHEAST OVER MISSOURI. STRONG
MOISTURE TRANSPORT AHEAD OF THE SYSTEM IS FUNNELING GULF OF MEXICO
MOISTURE INTO THE WESTERN GREAT LAKES REGION. MODERATE TO HEAVY
SNOW IS CREEPING NORTHWARD INTO CENTRAL WISCONSIN AND THE SOUTHERN
FOX VALLEY. MIXED PRECIP MOVED INTO SOUTHERN WISCONSIN EARLIER THIS
MORNING...BUT HAVE NOT SEEN A MIXED PRECIP OB NORTH OF I-94 YET.
NORTHEAST WINDS HAVE BEEN GRADUALLY INCREASING AS THE PRESSURE
GRADIENT TIGHTENS...WITH SOME GUSTS APPROACHING 40 KTS ALONG THE
LAKE SHORE. AS THE LOW MOVES CLOSER TO THE REGION AND PRECIPITATION
CONTINUES TO ADVANCE NORTHWARD...IMPACTS FROM HEAVY SNOW AND STRONG
WINDS ARE THE MAIN FORECAST CONCERNS.
TONIGHT...LOW PRESSURE WILL MOVE NORTHEAST FROM WEST-CENTRAL
ILLINOIS TO CENTRAL LAKE MICHIGAN. THIS TRACK IS SLIGHTLY TO THE
SOUTHEAST OF THE TRACK GIVEN BY THE MAJORITY OF GUIDANCE YESTERDAY.
AS A RESULT...THERMAL PROFILES CONTINUE TO SHOW A COOLER LOOK LIKE
THE PREVIOUS SHIFT MENTIONED. OBSERVATIONS ALSO BEAR OUT THIS TREND.
ADDITIONALLY...STRONG MOISTURE TRANSPORT AND PWATS APPROACHING 1
INCH WILL SHIFT NORTHEAST AHEAD OF THE LOW OVER SOUTHERN TO
NORTHEAST WISCONSIN. CONSEQUENTLY...THE SHORTER TERM GUIDANCE
INCLUDING THE SREF/CONSSHORT/RAP HAVE INCREASED QPF AMOUNTS OVER
NORTHEAST WISCONSIN SUBSTANTIALLY...AND HAVE FOLLOWED SUIT IN THE
FORECAST. THE END RESULT WAS A INCREASE OF SNOW AMOUNTS OVER
CENTRAL TO NORTHEAST WISCONSIN INTO THE 8-12 INCH RANGE. FAR NORTH-
CENTRAL WI CONTINUES TO LOOK TO SEE THE LOWEST AMOUNTS IN THE
REGION...MORE LIKE IN THE 3-5 INCH RANGE. THE STORM WILL LIKELY
PEAK DURING THE LATE AFTERNOON AND EVENING HOURS...WHERE AN 1+ INCH
SNOW FALL RATES AND WINDS TO 45 MPH WILL CREATE NEAR BLIZZARD
CONDITIONS AT TIMES. A BLIZZARD WARNING MAY BE NEEDED IF
VISIBILITIES REMAIN SUSTAINED BELOW A QUARTER MILE DESPITE THE
EXPECTED WET SNOW FLAKES...THAT TEND TO STICK TOGETHER RATHER THAN
BREAK UP IN STRONG WINDS. SOME SLEET MAY MIX WITH THE SNOW OVER
CENTRAL AND NORTHEAST WI LATE THIS AFTERNOON OR EARLY THIS
EVENING...BUT DO NOT THINK IT WILL HURT SNOWFALL ACCUMS MUCH. THE
SNOW WILL TRAIL OFF FROM SW TO NORTHEAST OVERNIGHT. PATCHY FREEZING
DRIZZLE MAY WORK IN WITH THE SNOWFLAKES LATE AS ICE CRYSTALS ARE
LOST ALOFT.
TUESDAY...THE LOW PRESSURE SYSTEM WILL SHIFT EAST OVER LAKE HURON.
DESPITE THE LOW MOVING AWAY...A TRAILING SHORTWAVE COMBINED WITH LOW
LEVEL CYCLONIC FLOW SHOULD KEEP LIGHT SNOW IN THE FORECAST FOR MUCH
OF THE DAY. FREEZING DRIZZLE WILL WORK IN THE WITH SNOW AT TIMES
WHEN POCKETS OF DRY AIR MOVE IN ALOFT. AN ADDITIONAL HALF TO ONE
INCH OF ACCUMULATIONS WILL BE POSSIBLE. HIGHS IN THE MID 20S NORTH
TO LOW 30S SOUTH.
.LONG TERM...TUESDAY NIGHT THROUGH MONDAY
ISSUED AT 224 PM CST MON DEC 28 2015
SPLIT FLOW TO CONT FROM THE ERN PACIFIC ACROSS THE CONUS...
HOWEVER THE NRN STREAM TO BECOME MORE DOMINANT THIS WEEK...THUS
PREVENTING ANY SRN STREAM SYSTEMS FROM IMPACTING THE GREAT LAKES.
A BUILDING UPR RDG INTO WRN CANADA WL RESULT IN A NW FLOW ALOFT
ACROSS WI WITH SNOW CHCS LIMITED TO WEAK CLIPPER-TYPE SYSTEMS OR
LAKE EFFECT SNOW SHWRS FROM LAKE SUPERIOR. TEMPS WL AVERAGE AT OR
SLIGHTLY ABOVE NORMAL...MAINLY DUE TO ABOVE NORMAL MIN TEMPS.
A LINGERING SFC BOUNDARY OVER SRN WI...COUPLED WITH THE PASSAGE OF
A MID-LEVEL SHORTWAVE...MAY BE ENUF TO KEEP AT LEAST A SMALL POP
IN THE FCST THRU MOST OF TUE NGT. FCST SOUNDINGS INDICATE DRIER
AIR ALOFT...THUS A POTENTIAL FOR FREEZING DRIZZLE RATHER THAN JUST
LIGHT SNOW. THE TRACK OF THE SHORTWAVE WOULD FAVOR NRN WI WITH A
HIGHER POP WITH MORE SNOW IN THE EVENING BEFORE MIXING WITH THE
FREEZING DRIZZLE. SNOW ACCUMULATIONS SHOULD REMAIN UNDER AN INCH
WITH LITTLE IN THE WAY OF ANY ICING. MAY NEED TO DROP MIN TEMPS A
COUPLE OF DEGS WHICH WOULD BRING READINGS INTO THE MID-TEENS
NORTH...AROUND 20 TO THE LWR 20S SOUTH.
MODELS CONT TO SEND ANOTHER SRN STREAM SYSTEM INTO THE GREAT LAKES
ON WED. THIS SYSTEM (COMPRISED OF A WEAK SFC LOW/NEGATIVELY-TILTED
SHORTWAVE TROF) IS MUCH WEAKER/MUCH LESS MOISTURE AVAILABLE THAN
ITS PREDECESSOR. THEREFORE...WHILE MOST OF NE WI WL SEE LIGHT SNOW
ON WED...ACCUMULATIONS WL BE MINOR WITH MOST LOCATIONS ONLY
RECEIVING ONE-HALF INCH OR LESS. MAX TEMPS TO RANGE FROM THE MID
TO UPR 20S NORTH...UPR 20S TO AROUND 30 DEGS SOUTH.
AS AN UPR RDG BEGINS TO BUILD INTO WRN CANADA...A DOWNSTREAM
POSITIVE-TILTED UPR TROF WL DEVELOP FROM CNTRL CANADA SW TO THE
CNTRL ROCKIES WED NGT. MODELS STILL SHOW PLENTY OF LOW-LEVEL
MOISTURE OVER WI AND WITH WEAK PIECES OF ENERGY TRAVERSING THE
AREA...CANNOT COMPLETELY RULE OUT A FEW SNOW SHWRS OR SCT FLURRIES
SOMEWHERE OVER NE WI. UNDER MAINLY CLOUDY SKIES...LOOK FOR MIN
TEMPS TO RANGE FROM 10-15 NORTH...15-20 SOUTH. THIS POSITIVELY-
TILTED UPR TROF IS FCST TO SHIFT EAST AND APPROACH THE WRN GREAT
LAKES LATE ON THU. WI TO ESSENTIALLY RESIDE IN AN AREA DEVOID OF
ANY LIFT OR FORCING AS MID-LEVEL SHORTWAVES AND JET STREAKS PASS
EITHER TO OUR NORTH (ONTARIO) OR SOUTH (OHIO RIVER VALLEY).
THEREFORE...ANTICIPATE MAINLY DRY CONDITIONS FOR THU WITH MAX
TEMPS IN THE UPR TEENS TO LWR 20S CNTRL WI...MIDDLE 20S ERN WI.
AS THIS UPR TROF DEPARTS NE WI THU NGT...A NW FLOW ALOFT IS LEFT
IN ITS WAKE WHICH WL THEN PERSIST OVER THE REGION INTO EARLY NEXT
WEEK. SEVERAL IMPULSES ARE EXPECTED TO MOVE SE THRU THIS FLOW OVER
WI (ONE ON FRI...ONE ON SAT AND A THIRD ON SUNDAY)...HOWEVER WITH
LITTLE MOISTURE AVAILABLE...IT WL BE DIFFICULT TO GENERATE MUCH
PCPN. THE THIRD PIECE OF ENERGY APPEARS TO BE THE STRONGEST OF THE
THREE AND MAY BE ABLE TO SQUEEZE OUT A FEW SNOW SHWRS OR FLURRIES
OVER THE FCST AREA. A BIGGER FCST HEADACHE MAY BE LAKE EFFECT
POTENTIAL FOR N-CNTRL WI FRI THRU SUNDAY. TRAJS DO NOT LOOK
FAVORABLE UNTIL SAT NGT AT THE EARLIEST AND EVEN WHEN WINDS DO
BECOME FAVORABLE...DELTA-T VALUES ARE FCST TO ONLY BE IN THE LWR
TEENS. THUS...LAKE EFFECT SNOW SHWRS DO NOT LOOK LIKE A MAJOR
ISSUE AT THIS TIME. BY MON...THE WEAKENING CANADIAN UPR RDG TO
RESIDE OVER THE CNTRL CONUS WITH A SPRAWLING SFC HI BUILDING INTO
WI. THESE FEATURES SHOULD KEEP OUR WEATHER QUIET WITH TEMPS GOING
SLIGHTLY ABOVE NORMAL FOR SUNDAY AND MON.
&&
.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1113 AM CST MON DEC 28 2015
A LARGE AND STRONG LOW PRESSURE SYSTEM WILL MOVE ACROSS THE FORECAST
AREA FROM THE CENTRAL MISSISSIPPI VALLEY THIS AFTERNOON THROUGH
MIDDAY TUESDAY. A LARGE PRECIPITATION SHIELD WILL SURGE NORTHWARD
AHEAD OF THE LOW...REACHING THE SOUTHERN FOX VALLEY BY 19Z AND
NORTHERN WI BETWEEN 00Z-02Z. A MIXTURE OF SNOW AND SLEET IS LIKELY
FROM SUE TO ISW SOUTHWARD. STRONG GUSTY NE WINDS UP TO 40 KTS WILL
CREATE BLOWING AND DRIFTING OF THE NEW SNOW. AS THE SNOW WINDS DOWN
LATE TONIGHT...FREEZING DRIZZLE WILL MIX IN WITH THE SNOW THROUGH
THE END OF THE TAF PERIOD. WINDS WILL ALSO DIMINISH TOMORROW
MORNING.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL 6 AM CST TUESDAY FOR WIZ045-048>050.
WINTER STORM WARNING UNTIL 6 AM CST TUESDAY FOR WIZ030-031-
035>040.
WINTER STORM WARNING FROM 6 PM THIS EVENING TO 9 AM CST TUESDAY
FOR WIZ005-010>013-018>022-073-074.
&&
$$
SHORT TERM.....MPC
LONG TERM......AK
AVIATION.......MPC
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1235 PM CST MON DEC 28 2015
.UPDATE...
WE INCREASED QPF AND SNOW AMOUNTS ACROSS SOUTHERN WI FOR THIS
AFTERNOON AND EVENING TO ACCOUNT FOR THE LATEST MODELS AND WEATHER
TRENDS. AREAS NORTHWEST OF MADISON COULD SEE UP TO 10 INCHES OF SNOW
TOTAL AND NEAR BLIZZARD CONDITIONS THIS AFTERNOON DURING THE
HEAVIEST SNOW.
12Z ECMWF CAME IN WITH THE COLDER TEMPERATURES ALOFT THAT THE GFS
HAD BEEN ADVERTISING. NAM AND RAP CONTINUE TO SHOW THE WARM LAYER
ABOVE FREEZING. WILL TAKE A COMPROMISE. THE LATEST RAP BUFKIT
TEMPERATURE PROFILES STILL SUPPORT FREEZING RAIN MAINLY SOUTH AND
EAST OF A MINERAL POINT TO WATERTOWN TO PORT WASHINGTON LINE. NORTH
AND WEST OF THAT LINE WILL SEE MOSTLY SLEET THIS AFTERNOON. THE
PRECIP TYPE IS EXPECTED TO REMAIN MOSTLY SNOW TOWARD THE DELLS...
THUS THE HIGHER SNOWFALL AMOUNTS.
PREVIOUS DISCUSSION BELOW. JUST KEEP IN MIND THAT THE RAP AND NAM
ARE WARMER THAN THE ECMWF AND GFS... SO MAYBE SUBTRACT A COUPLE OF
DEGREES FOR THE WARM LAYER TO GO WITH A COMPROMISE.
THE WARM LAYER WITH +5C ALOFT WILL LIFT INTO SOUTHEAST WI AFTER
20Z/2 PM THIS AFTERNOON WHICH WILL PRODUCE MORE FREEZING RAIN AND
LESS SLEET... POSSIBLY RAIN DEPENDING ON THE SURFACE TEMPERATURE AT
THAT TIME. THAT WARM LAYER WILL ONLY BE -3C TO -4C IN MADISON SO
EXPECT MORE SLEET THERE. TOWARD THE DELLS... THE WARM LAYER ONLY
REACHES +1 OR LESS... SO WE CAN EXPECT ALMOST ALL SNOW THERE WITH A
MIX OF SLEET. THE AFTERNOON HOURS WILL BE THE TIME OF HEAVIEST
PRECIP.
THE DEEP COLD LAYER WITH MIN TEMP OF -5C TO -6 C IN THE LOWEST 4000
FEET SEEMS CONSISTENT ACROSS ALL OF SOUTHERN WI AND NO MATTER WHICH
MODEL. THIS COLD LAYER WILL HELP TO RE-FREEZE THE LIQUID PRODUCED
FROM THE WARM LAYER INTO SLEET OR FREEZING RAIN. IT MIGHT NOT BE
SUFFICIENTLY COLD TO FREEZE IT INTO ALL SLEET IN SOUTHEAST WI GIVEN
THE DEPTH OF THE WARM LAYER... SO FREEZING RAIN IS A BIG CONCERN.
WIND IS THE OTHER BIG STORY TODAY. THE WIND WILL HELP TO REDUCE
VISIBILITY IN SNOW AND SLEET. VISIBILITY COULD BE REDUCED TO A
QUARTER MILE OR LESS AT TIMES THIS AFTERNOON. WIND WILL ALSO
INCREASE RISK OF DOWNED TREES AND POWER LINES WITH FREEZING RAIN
ACCUMULATION.
BOTTOM LINE IS THAT TRAVEL WILL BE DIFFICULT... LAWN ORNAMENTS WILL
BLOW AROUND... AND EXPECT A VERY TREACHEROUS AFTERNOON COMMUTE.
.AVIATION/18Z TAFS/...
SNOW SPREAD INTO ALL OF SOUTHERN WI THIS MORNING. LATEST MODEL
SOUNDINGS/TEMPERATURE PROFILE SUPPORT ALL SNOW UNTIL A WARM LAYER
WRAPS NORTHWARD INTO SOUTH CENTRAL AND SOUTHEAST WI AFTER 20Z/2 PM
THIS AFTERNOON. THAT WARM LAYER WILL PRODUCE A PERIOD OF FREEZING
RAIN OR SLEET... DEPENDING ON HOW FAR NORTH IT GETS. RIGHT NOW IT IS
LOOKING LIKE MSN TO PORT WASHINGTON AND TO THE WEST AND NORTH IS THE
LINE WHERE WE WILL SEE MAINLY SLEET RATHER THAN FREEZING RAIN. EAST
AND SOUTH OF THERE HAS THE BETTER CHANCE OF FREEZING RAIN RATHER
THAN SLEET. THE SURFACE TEMPS WILL BE HOVERING RIGHT AROUND FREEZING
IN FAR SOUTHEAST WI SO NOT SURE IF MKE AND ENW WILL HAVE FZRA OR RA
LATE THIS AFTERNOON.
MVFR/ FUEL ALT CIGS WILL LOWER TO IFR THIS AFTERNOON. CIGS COULD
DROP LOWER THAN 600 FEET LATE THIS AFTERNOON AND THROUGH THE
EVENING. THE HEAVIEST PRECIP WILL FALL THIS AFTERNOON BETWEEN 20Z
AND 02Z. EXPECT VERY LOW VISIBILITY DUE TO THE WIND AND FALLING
PRECIP.
&&
.PREV DISCUSSION... /ISSUED 919 AM CST MON DEC 28 2015/
UPDATE...
MARINE...
VERY STRONG PRESSURE GRADIENT ASSOCIATED WITH LOW PRESSURE OVER
ARKANSAS WILL RESULT IN EXTREMELY WINDY CONDITIONS OVER THE
NEARSHORE WATERS TODAY INTO TONIGHT. WIND SPEEDS WILL CONTINUE TO
INCREASE INTO THE EARLY AFTERNOON WITH STORM FORCE GUSTS OF 48 TO 50
KNOTS EXPECTED. THIS STRONG ONSHORE FLOW WILL CAUSE HIGH WAVES OF 9
TO 13 FEET THIS AFTN AND EVE. MARINE TRAVEL IS STRONGLY NOT
RECOMMENDED. A STORM WARNING REMAINS IN EFFECT THROUGH THIS
EVENINIG.
THE WINDS WILL RAPIDLY DECREASE LATER TONIGHT AS THE LOW PRESSURE
SYSTEM MOVES ACROSS SOUTHERN WISCONSIN AND LAKE MICHIGAN.
WILL CONTINUE LAKESHORE FLOOD ADVISORY AS ONSHORE WINDS WILL LIKELY
GUST AS HIGH AS 50 MPH THIS AFTERNOON AND EARLY EVENING.WAVE HEIGHTS
CRASHING ONSHORE MAY REACH 11-13 FEET DURING THIS TIME. SOME BEACH
EROSION MAY OCCUR ALONG WITH DAMAGE TO STRUCTURES. EMPHASIZE
REMAINING AWAY FROM THE LAKE MICHIGAN SHORE BY THEWATERS FOR SAFETY.
PREV DISCUSSION... /ISSUED 913 AM CST MON DEC 28 2015/
UPDATE...
SNOW ALREADY DEVELOPED ACROSS SOUTHERN WI THIS MORNING. THAT DRY
LAYER IN THE LOW LEVELS ERODED QUICKLY. RAP AND OTHER MODEL
SOUNDINGS SUPPORT SNOW/SLEET THROUGH THE MORNING HOURS. THIS MEANS
WE WILL NEED TO INCREASE SNOWFALL AMOUNTS THROUGH 20Z. WE COULD SEE
AN INCH BUT I AM STILL WORKING ON THE DETAILS.
THE WARM LAYER WITH +5C ALOFT WILL LIFT INTO SOUTHEAST WI AFTER
20Z/2 PM THIS AFTERNOON WHICH WILL PRODUCE MORE FREEZING RAIN AND
LESS SLEET... POSSIBLY RAIN DEPENDING ON THE SURFACE TEMPERATURE AT
THAT TIME. THAT WARM LAYER WILL ONLY BE -3C TO -4C IN MADISON SO
EXPECT MORE SLEET THERE. TOWARD THE DELLS... THE WARM LAYER ONLY
REACHES +1 OR LESS... SO WE CAN EXPECT ALMOST ALL SNOW THERE WITH A
MIX OF SLEET. THE AFTERNOON HOURS WILL BE THE TIME OF HEAVIEST
PRECIP.
THE DEEP COLD LAYER WITH MIN TEMP OF -5C TO -6 C IN THE LOWEST 4000
FEET SEEMS CONSISTENT ACROSS ALL OF SOUTHERN WI. THIS COLD LAYER
WILL HELP TO RE-FREEZE THE LIQUID PRODUCED FROM THE WARM LAYER INTO
SLEET OR FREEZING RAIN. IT MIGHT NOT BE SUFFICIENTLY COLD TO FREEZE
IT INTO ALL SLEET IN SOUTHEAST WI GIVEN THE DEPTH OF THE WARM
LAYER... SO FREEZING RAIN IS A BIG CONCERN.
WIND IS THE OTHER BIG STORY TODAY. THE WIND WILL HELP TO REDUCE
VISIBILITY IN SNOW AND SLEET. VISIBILITY COULD BE REDUCED TO A
QUARTER MILE OR LESS AT TIMES THIS AFTERNOON. WIND WILL ALSO
INCREASE RISK OF DOWNED TREES AND POWER LINES WITH FREEZING RAIN
ACCUMULATION.
I AM WORKING TO INCREASE SNOWFALL/SLEET AMOUNTS THIS MORNING AND
WILL CONTINUE TO UPDATE WEATHER TYPES. BOTTOM LINE IS THAT TRAVEL
WILL BE DIFFICULT... LAWN ORNAMENTS WILL BLOW AROUND... AND EXPECT
A VERY TREACHEROUS AFTERNOON COMMUTE.
PREV DISCUSSION... /ISSUED 347 AM CST MON DEC 28 2015/
TODAY AND TONIGHT...FORECAST CONFIDENCE MEDIUM.
MODELS ARE A LITTLE MORE IN LINE WITH THE SURFACE TRACK WITH THE GFS
STILL A LITTLE MORE SOUTH AND EAST. THE NAM IS SIMILAR TO THE ECMWF
BUT THE ECMWF IS A LITTLE FARTHER WEST LIKE THE HIGH RESOLUTION MESO
MODELS ESPECIALLY THE HRRR.
PRECIPITATION SHOULD REACH THE GROUND ALONG THE ILLINOIS BORDER AREA
AROUND 9AM CST AND REACH THE FOND DU LAC AND SHEBOYGAN AREAS JUST
AFTER 1 PM.
THIS WILL BE A VERY WET SYSTEM WITH PRECIPITABLE WATER VALUES UP
0.90 INCH BEING DRIVEN BY A 50 KNOT LOW LEVEL JET AHEAD OF A
COMPACT...OCCLUDING LOW PRESSURE SYSTEM. THERE WILL BE VERY STRONG
SYNOPTIC FORCING WITH THIS SYSTEM... WITH LAYER Q-VECTOR CONVERGENCE
OF 20 TO 50 UNITS AND VERY STRONG OMEGA DURING THE AFTERNOON
AND EARLY EVENING TIME PERIOD. WE ARE EXPECTING 0.50 TO 0.75 INCH OF
QPF/LIQUID PRECIP WITHIN 6 HOURS MONDAY AFTERNOON. THE BIG QUESTION
CONTINUES TO BE PRECIP TYPE.
ALTHOUGH THE GFS IS STILL COOLER WITH THE THERMAL PROFILES...MOST
MODELS ARE KEYING ON SLEET BEING THE BIGGEST FACTOR WITH THIS STORM
OVER THE FORECAST AREA...WITH FREEZING RAIN ALSO A CONCERN...EXCEPT
FAR EAST NEAR LAKE MICHIGAN WITH THE WARMER LAKE WATERS. FARTHER
WEST AND NORTH MORE OF A SNOW MIX IS EXPECTED. DUE TO EVAPORATIVE
COOLING MANY AREAS COULD SEE SOME SNOW INITIALLY.
AS THE LOW APPROACHES THE PRECIPITATION WILL TURN MORE RAIN IN THE
FAR SOUTHEAST...THEN A VARIETY OF DRIZZLE TYPES NEAR THE LOW. SOME
TRANSITION BACK TO LIGHT SNOW AS THE MID LEVEL LOW MOVES OVER.
STRONG EAST WINDS WILL FURTHER EXACERBATE TRAVEL CONDITIONS WITH
PERIODS OF WHITEOUT CONDITIONS IN THE MORE SNOW AREAS WEST OF
MADISON AND POTENTIAL IMPACTS FROM UP TO 0.10 TO 0.20 INCH OF
FREEZING RAIN. THUS A WINTER STORM WARNING CONTINUES FOR ALL OF
SOUTHERN AND EAST CENTRAL WISCONSIN.
GUSTY EAST WINDS WILL STEADILY INCREASE THIS MORNING AND BECOME VERY
STRONG BY MONDAY AFTERNOON. WIND GUSTS OF 40 TO 45 MPH
LIKELY...WITH SOME 50 MPH GUSTS POSSIBLE ESPECIALLY HIGH AREAS AND
NEAR LAKE MICHIGAN.
TUESDAY - CONFIDENCE...MEDIUM
LINGERING MID LEVEL CYCLONIC FLOW AS FIRST WAVE LIFTS NORTHEAST FROM
SRN WI AND SECONDARY WAVE SHIFTS SLOWLY NE FROM SRN MN VCNTY. BY
AFTERNOON MID LEVEL FLOW EXPECTED TO BR BROADLY ANTICYCLONIC.
SFC/850 CONVERGENCE PERSISTS IN THE MORNING AS LOW WEAKENS FURTHER
AND SHIFTS NE AWAY FROM LWR MI VCNTY. CONVERGENCE WEAKENS DURG THE
AFTN AND SHIFTS NORTH AWAY FROM SRN WI. MODELS ARE ALL SHOWING
SOME LIGHT QPF PERSISTING DURG THE MRNG HRS. OF PARTICULAR CONCERN
IS THE MID LEVEL DRYING WHICH RESULTS IN THE LOSS OF SATURATION
WITHIN THE DENDRIDIC GROWTH ZONE. SO EXPECT SOME FREEZING DRIZZLE
IN THIS SCENARIO. HIGHEST POPS WILL BE IN THE MORNING WITH A SHIFT
TOWARDS CONFINING POPS TO THE THE NORTHERN REACHES OF THE CWA FOR
THE AFTN HRS. LLVL RH PROGS KEEP THINGS MOIST SO STAYING
PESSIMISTIC WRT CLOUD COVER.
WEDNESDAY - CONFIDENCE...MEDIUM
ELONGATED VORT AXIS THEN PROGGD TO SHIFT NE FROM BASE OF WRN
TROUGH. NOT MUCH IN THE WAY OF A SFC REFLECTION TO THIS THOUGH A
SFC/850 TROUGH LIKELY TO AID IN SOME VERTICAL MOTION. QPF AMOUNTS
ARE LIGHT AND IN THIS CASE WE ARE SEEING ENOUGH SATURATION IN THAT
DENDRIDIC GROWTH ZONE TO GO WITH ALL SNOW ON THE PRECIP TYPE. SO
OVERALL LOOKS LIKE SOME AREAS SEE A 1/2 INCH OF SNOW.. THE GFS HAS
A SMIDGE HIGHER QPF THAT WOULD PERHAPS PUSH AN INCH BUT WILL GO
WITH MORE OF A CONSENSUS APPROACH WRT QPF AT THIS TIME.
THURSDAY THROUGH SUNDAY - CONFIDENCE...MEDIUM
OVERALL QUIET NW FLOW REGIME. GFS SUGGESTS SOME SHSN POTENTIAL
FOR THU BUT ECMWF IS DRY AND SUPERBLEND POPS LEAN THIS WAY. MAY
NEED A SMALL POP OR SOME FLURRIES EVENTUALLY BUT FOR NOW WILL KEEP
THINGS DRY. 925 TEMPS SUPPORT HIGHS MOSTLY IN THE 20S TO LOW 30S.
AVIATION/12Z TAFS/...
AVIATION/12Z TAFS/...THE EAST WINDS HAVE PUSHED AN MVFR CLOUD DECK
ACROSS MUCH OF SOUTHERN WISCONSIN DUE TO MOISTURE OFF LAKE MICHIGAN.
A STRONG LOW WILL MOVE ACROSS THE MID MISSISSIPPI VALLEY AND INTO
NORTHERN ILLINOIS THIS EVENING. PRECIPITATION WILL SPREAD NORTH.
INITIALLY DRY AIR WILL CAUSE VIRGA...BUT THE STRONG VERTICAL MOTION
WILL CAUSE PRECIPITATION TO REACH THE GROUND MID MORNING FAR SOUTH
AND TOWARDS NOON NEAR FOND DU LAC AND SHEBOYGAN. A WARM SURGE
AROUND 7 TO 9 THSD FT WILL CAUSE A MIX OF PRECIPITATION TO DEVELOP
WITH SLEET THE PREDOMINATE TYPE MOST AREAS. SOME FREEZING RAIN WILL
LATER THIS AFTERNOON INLAND AREAS. SNOW MAY FALL WITH THE ONSET AND
ALSO A MIX OF SNOW AND SLEET ESPECIALLY NORTH AND WEST OF
MADISON.
CIGS/VSBYS BECOMING IFR/LIFR THIS AFTERNOON AND EVENING.
NORTHEAST WINDS WILL VEER EAST...INCREASING TO 30 KNOTS MID-LATE
MORNING AND 40 KNOTS IN THE AFTERNOON...WITH 45 KNOT GUSTS IN THE
FAR EAST.
MARINE...WILL UPGRADE TO A STORM WARNING. HIGHEST STORM FORCE
GUSTS EXPECTED LATE AFTERNOON AND EARLY EVENING.
LATEST HIGH RESOLUTION HRRR EXPERIMENTAL SUPPORTS A HIGH-END GALE
WARNING...WITH STORM FORCE GUSTS LIKELY LATE AFTERNOON AND EARLY
EVENING. WILL OBVIOUSLY NEED A SMALL CRAFT ADVISORY FOR A TIME
OVERNIGHT MONDAY NIGHT AND TUESDAY AFTER THE GALE WARNING EXPIRES
AND THE LOW MOVES INTO SOUTHERN LAKE MICHIGAN DIMINISHING THE
WINDS.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...WINTER STORM WARNING UNTIL 6 AM CST TUESDAY FOR WIZ046-047-051-
052-056>060-062>072.
LAKESHORE FLOOD ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR WIZ052-
060-066-071-072.
LM...STORM WARNING UNTIL 10 PM CST THIS EVENING FOR LMZ643>646.
&&
$$
UPDATE...MRC
TODAY/TONIGHT AND AVIATION/MARINE...HENTZ
TUESDAY THROUGH SUNDAY...COLLAR
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1116 AM CST MON DEC 28 2015
NEW INFORMATION ADDED TO UPDATE SECTION
.UPDATE...
ISSUED AT 1113 AM CST MON DEC 28 2015
BASED ON THE NORTHERN MOVEMENT OF THE PRECIPITATION SHIELD...HAVE
DECIDED TO BUMP UP START TIME OF THE WINTER STORM WARNING FROM
WAUTOMA TO MANITOWOC TO 18Z. SNOW HAS ALREADY STARTED AT FOND DU
LAC BASED ON WEB CAMS. THE DRY AIR MAY DELAY THE HEAVIER SNOW
SLIGHTLY...BUT EXPECT HEAVIER SNOW TO BEGIN TO IMPACT THE SOUTHERN FOX
VALLEY DURING THE 19-20Z TIME PERIOD.
&&
UPDATE
ISSUED AT 714 AM CST MON DEC 28 2015
THE LATEST SHORT-RANGE MODELS STARTING TO LOOK VERY OMINOUS FOR
E-C WI. IT/S LOOKING MORE AND MORE LIKE THE WARM AIR ALOFT WL
HAVE A HARD TIME MAKING INTO INTO E-C WI. THAT RAISES THE
POSSIBILITY THAT MOST OF THE PCPN WL BE SNOW. WITH IMPRESSIVE
RADAR RETURNS LINED UP FM NRN IL DOWN TO THE GULF...THAT COULD
REALLY DESTROY THE SNOWFALL FCST. COBB OUTPUT OFF THE LATEST RAP
AND HRRR HAVE 14.1 AND 5.9 INCHES OF SNOW IN GRB BY THE END OF THE
MODEL RUNS /HRRR COVERS LESS TIME AS MODEL RUN IS SHORTER/...WITH
THE EVENT STILL ONGOING. INTERESTINGLY...THEY BOTH ACTUALLY
INDICATE A BETTER SLEET POTENTIAL BACK IN CENTRAL WI. MY INITIAL
GUESS WOULD BE DRY AIR FEEDING IN FM RECEDING ANTICYCLONE IS
LEADING TO MORE COOLING IN THE E...KEEPING SOUNDINGS ALL SNOW
THERE.
DON/T WANT TO OVERREACT TO A COUPLE MODELS...BUT STARTING TO GET
VERY NERVOUS THAT GOING SNOW FCST FOR E-C WI WILL NOT HOLD. THE
MAGNITUDE OF THE COLD AIR IS ALSO REINFORCED BY THE FACT SNOW IS
STILL FALLING AT THE LEADING EDGE OF THE PCPN WAY DOWN IN NRN IL.
WL UPDATED PRODUCT SUITE TO PUSH SNOW TOTALS HIGHER. WL ALSO
MENTION NEAR BLIZZARD CONDITIONS IN E-C WI. TRAVEL LATE THIS
AFTN/EVENING IS LOOKING LIKE IT COULD BECOME A REAL NIGHTMARE.
&&
.SYNOPSIS...
ISSUED AT 602 AM CST MON DEC 28 2015
MAJOR WINTER STORM TO IMPACT THE AREA THIS AFTERNOON THROUGH
TUESDAY...A LITTLE MORE SNOW POSSIBLE MID-WEEK...THEN QUIETER FOR
THE REST OF THE PERIOD.
THE UPPER FLOW ACRS NOAM WL REMAIN SPLIT WITH 2 MORE ENERGETIC
SRN STREAM SYSTEMS TO CROSS THE REGION THE NEXT SEVERAL DAYS. THE
SPLIT WILL RE-STRUCTURE ITSELF LATE IN THE WEEK INTO THE UPCOMING
WEEKEND...WITH MORE OF THE WESTERLIES JOINING THE NRN STREAM...
AND THE SRN STREAM BECOMING WEAKER AND DISPLACED FARTHER SOUTH.
THAT WL USHER IN A MORE TRANQUIL WEATHER REGIME...WITH
TEMPERATURES DROPPING BACK CLOSER TO SEASONAL NORMALS THAN WE/VE
HAD IN A WHILE.
&&
.SHORT TERM...TODAY...TONIGHT...AND TUESDAY
ISSUED AT 602 AM CST MON DEC 28 2015
FCST FOCUS IS IN LINING UP THE DETAILS OF THE FCST FOR THE
INCOMING STORM SYSTEM. INTENSE UPR SYSTEM THAT TRACKED AMAZINGLY
FAR S ACRS TEXAS /AT LEAST FOR SOMETHING THAT/S GOING TO AFFECT
WI/ WL TURN NNE AND ABSOLUTELY RACE TO NRN IL BY LATE EVENING. STG
DEEP SLY FLOW ACRS THE ENTIRE GULF IS FEEDING ABUNDANT MOISTURE
NWD. PCPN SHIELD FM NRN IL DOWN TO THE GULF COAST WL CONT TO
SURGE NWD...THEN PIVOT ARND UPR SYSTEM AS IT ARRIVES IN THE AREA.
THE CHANGE IN THE GUIDANCE DURING THE PAST 24 HRS HAS BEEN TOWARD
A CONSENSUS TRACK OF THE UPR LOW ACRS SERN WI. SFC LOW WL BE
VERTICALLY STACKED UNDERNEATH BY THAT POINT. THAT/S PRETTY MUCH A
CLASSIC TRACK FOR HEAVY SNOW ACRS E-C WI. THERMAL FIELDS HAVE
FALLEN IN LINE. EACH SUCCESSIVE RUN OF THE WARM-OUTLIER NAM HAS
TRENDED COLDER. BUFR SOUNDINGS FM THE 06Z NAM WERE DOWN TO JUST A
SINGLE HR OF SLEET AT GRB /8 PM/. SO WITH MORE THE PCPN TO FALL AS
SNOW...UPPED TOTALS IN E-C WI FM PREV FCST. STILL A LITTLE
CONCERNED ABOUT PCPN TYPE IN THE SRN EDGE OF THE FCST AREA AND THE
LAKE MICHIGAN SHORELINE LOCATIONS. UPPED SNOWFALLS IN THESE AREAS
AS WELL...BUT FURTHER UPWARD ADJUSTMENT MAY BE NECESSARY IF THE
THE PROFILES CONT TO TREND COLDER. THE OTHER CHG WAS TO BACK DOWN
ON TOTALS A BIT IN VILAS COUNTY AS IT APPEARS THAT AREA WL BE ON
THE NW FRINGE OF THE HEAVY SNOWS.
STG ELY WINDS COMBINED WITH HEAVY SNOW WL MAKE A REAL MESS OF
TRAVEL LATE THIS AFTN INTO THIS EVENING. IT MIGHT HAVE BEEN IDEAL
TO HAVE HAD A START TIME OF THE WARNING AN HOUR OR TWO EARLIER
OVER THE FAR S...BUT NOT SURE THAT SMALL A CHANGE WOULD REALLY
HAVE MEANING AT THIS POINT. HAVE HIGHLIGHTED MY BEST GUESS AT
TIMING WITH SHARP POP GRADIENT IN THE GRIDS...AND IN AN SPS.
CONSIDERED THE POSSIBILITY OF GETTING BLIZZARD CONDITIONS IN E-C
WI FOR A TIME DURING THE LATE AFTN/EVENING. BUT HAVE SEEN SEVERAL
SITNS WITH TEMP PROFILES HAVING A DEEP NEAR FREEZING LAYER WHERE
SNOWFLAKES TEND TO STICK TOGETHER...SO VSBYS DON/T GO DOWN AS MUCH
AS NORMALLY ASSOCIATED WITH INCH AN HOUR SNOWS. GIVEN THE STRENGTH
OF THE DYNAMICS...A FEW RUMBLES OF THUNDER ALSO NOT OUT OF THE
QUESTION.
SNOWS WILL TAPER OFF FM S-N OVERNIGHT. SCT SHSN AND AREAS OF FZDZ
/DUE TO LOSS OF MID-LVL MOISTURE/ WL CONT INTO TUESDAY. IT/S
POSSIBLE A MESO-SCALE SNOW BAND COULD SET UP SOMEWHERE AND
PRODUCE ANOTHER 2-4 INCHES OF SNOW. DON/T KNOW FOR SURE IF/WHERE
THAT WOULD HAPPEN...BUT MOST CONCERNED ABOUT N-C WI DURING THE
AFTN AS DEFORMATION ZONE ON THE NW FLANK OF REMNANTS OF MID-LVL
CIRCULATION WL BE LINGERING IN THAT REGION.
.LONG TERM...TUESDAY NIGHT THROUGH SUNDAY
ISSUED AT 351 AM CST MON DEC 28 2015
ANOTHER UPPER LEVEL SYSTEM WILL CROSS THE AREA LATE TUESDAY NIGHT
INTO WEDNESDAY EVENING. MOISTURE WILL BE MUCH MORE LIMITED...BUT
THE SYSTEM COULD BRING SOME LIGHT SNOWS TO THE AREA.
COLDER AIR WILL SETTLE INTO THE AREA BEHIND THAT SYSTEM. HIGH
TEMPS WL BE NEAR OR MAYBE A LITTLE BELOW NORMAL. MIN TEMPS WILL
DEPEND ON CLOUD COVER. WITH A FRESH DEEP SNOWCOVER...ANY NIGHTS
WITH CLEAR SKIES AND LGTS WINDS COULD GET QUITE COLD.
&&
.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1113 AM CST MON DEC 28 2015
A LARGE AND STRONG LOW PRESSURE SYSTEM WILL MOVE ACROSS THE FORECAST
AREA FROM THE CENTRAL MISSISSIPPI VALLEY THIS AFTERNOON THROUGH
MIDDAY TUESDAY. A LARGE PRECIPITATION SHIELD WILL SURGE NORTHWARD
AHEAD OF THE LOW...REACHING THE SOUTHERN FOX VALLEY BY 19Z AND
NORTHERN WI BETWEEN 00Z-02Z. A MIXTURE OF SNOW AND SLEET IS LIKELY
FROM SUE TO ISW SOUTHWARD. STRONG GUSTY NE WINDS UP TO 40 KTS WILL
CREATE BLOWING AND DRIFTING OF THE NEW SNOW. AS THE SNOW WINDS DOWN
LATE TONIGHT...FREEZING DRIZZLE WILL MIX IN WITH THE SNOW THROUGH
THE END OF THE TAF PERIOD. WINDS WILL ALSO DIMINISH TOMORROW
MORNING.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL 6 AM CST TUESDAY FOR WIZ045-048>050.
WINTER STORM WARNING FROM 3 PM THIS AFTERNOON TO 6 AM CST
TUESDAY FOR WIZ030-031-035>040.
WINTER STORM WARNING FROM 6 PM THIS EVENING TO 9 AM CST TUESDAY
FOR WIZ005-010>013-018>022-073-074.
&&
$$
UPDATE.........MPC
SYNOPSIS.......SKOWRONSKI
SHORT TERM.....SKOWRONSKI
LONG TERM......ECKBERG
AVIATION.......MPC
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1113 AM CST MON DEC 28 2015
UPDATED AVIATION PORTION FOR 18Z TAF ISSUANCE
.UPDATE...
ISSUED AT 714 AM CST MON DEC 28 2015
THE LATEST SHORT-RANGE MODELS STARTING TO LOOK VERY OMINOUS FOR
E-C WI. IT/S LOOKING MORE AND MORE LIKE THE WARM AIR ALOFT WL
HAVE A HARD TIME MAKING INTO INTO E-C WI. THAT RAISES THE
POSSIBILITY THAT MOST OF THE PCPN WL BE SNOW. WITH IMPRESSIVE
RADAR RETURNS LINED UP FM NRN IL DOWN TO THE GULF...THAT COULD
REALLY DESTROY THE SNOWFALL FCST. COBB OUTPUT OFF THE LATEST RAP
AND HRRR HAVE 14.1 AND 5.9 INCHES OF SNOW IN GRB BY THE END OF THE
MODEL RUNS /HRRR COVERS LESS TIME AS MODEL RUN IS SHORTER/...WITH
THE EVENT STILL ONGOING. INTERESTINGLY...THEY BOTH ACTUALLY
INDICATE A BETTER SLEET POTENTIAL BACK IN CENTRAL WI. MY INITIAL
GUESS WOULD BE DRY AIR FEEDING IN FM RECEDING ANTICYCLONE IS
LEADING TO MORE COOLING IN THE E...KEEPING SOUNDINGS ALL SNOW
THERE.
DON/T WANT TO OVERREACT TO A COUPLE MODELS...BUT STARTING TO GET
VERY NERVOUS THAT GOING SNOW FCST FOR E-C WI WILL NOT HOLD. THE
MAGNITUDE OF THE COLD AIR IS ALSO REINFORCED BY THE FACT SNOW IS
STILL FALLING AT THE LEADING EDGE OF THE PCPN WAY DOWN IN NRN IL.
WL UPDATED PRODUCT SUITE TO PUSH SNOW TOTALS HIGHER. WL ALSO
MENTION NEAR BLIZZARD CONDITIONS IN E-C WI. TRAVEL LATE THIS
AFTN/EVENING IS LOOKING LIKE IT COULD BECOME A REAL NIGHTMARE.
&&
.SYNOPSIS...
ISSUED AT 602 AM CST MON DEC 28 2015
MAJOR WINTER STORM TO IMPACT THE AREA THIS AFTERNOON THROUGH
TUESDAY...A LITTLE MORE SNOW POSSIBLE MID-WEEK...THEN QUIETER FOR
THE REST OF THE PERIOD.
THE UPPER FLOW ACRS NOAM WL REMAIN SPLIT WITH 2 MORE ENERGETIC
SRN STREAM SYSTEMS TO CROSS THE REGION THE NEXT SEVERAL DAYS. THE
SPLIT WILL RE-STRUCTURE ITSELF LATE IN THE WEEK INTO THE UPCOMING
WEEKEND...WITH MORE OF THE WESTERLIES JOINING THE NRN STREAM...
AND THE SRN STREAM BECOMING WEAKER AND DISPLACED FARTHER SOUTH.
THAT WL USHER IN A MORE TRANQUIL WEATHER REGIME...WITH
TEMPERATURES DROPPING BACK CLOSER TO SEASONAL NORMALS THAN WE/VE
HAD IN A WHILE.
&&
.SHORT TERM...TODAY...TONIGHT...AND TUESDAY
ISSUED AT 602 AM CST MON DEC 28 2015
FCST FOCUS IS IN LINING UP THE DETAILS OF THE FCST FOR THE
INCOMING STORM SYSTEM. INTENSE UPR SYSTEM THAT TRACKED AMAZINGLY
FAR S ACRS TEXAS /AT LEAST FOR SOMETHING THAT/S GOING TO AFFECT
WI/ WL TURN NNE AND ABSOLUTELY RACE TO NRN IL BY LATE EVENING. STG
DEEP SLY FLOW ACRS THE ENTIRE GULF IS FEEDING ABUNDANT MOISTURE
NWD. PCPN SHIELD FM NRN IL DOWN TO THE GULF COAST WL CONT TO
SURGE NWD...THEN PIVOT ARND UPR SYSTEM AS IT ARRIVES IN THE AREA.
THE CHANGE IN THE GUIDANCE DURING THE PAST 24 HRS HAS BEEN TOWARD
A CONSENSUS TRACK OF THE UPR LOW ACRS SERN WI. SFC LOW WL BE
VERTICALLY STACKED UNDERNEATH BY THAT POINT. THAT/S PRETTY MUCH A
CLASSIC TRACK FOR HEAVY SNOW ACRS E-C WI. THERMAL FIELDS HAVE
FALLEN IN LINE. EACH SUCCESSIVE RUN OF THE WARM-OUTLIER NAM HAS
TRENDED COLDER. BUFR SOUNDINGS FM THE 06Z NAM WERE DOWN TO JUST A
SINGLE HR OF SLEET AT GRB /8 PM/. SO WITH MORE THE PCPN TO FALL AS
SNOW...UPPED TOTALS IN E-C WI FM PREV FCST. STILL A LITTLE
CONCERNED ABOUT PCPN TYPE IN THE SRN EDGE OF THE FCST AREA AND THE
LAKE MICHIGAN SHORELINE LOCATIONS. UPPED SNOWFALLS IN THESE AREAS
AS WELL...BUT FURTHER UPWARD ADJUSTMENT MAY BE NECESSARY IF THE
THE PROFILES CONT TO TREND COLDER. THE OTHER CHG WAS TO BACK DOWN
ON TOTALS A BIT IN VILAS COUNTY AS IT APPEARS THAT AREA WL BE ON
THE NW FRINGE OF THE HEAVY SNOWS.
STG ELY WINDS COMBINED WITH HEAVY SNOW WL MAKE A REAL MESS OF
TRAVEL LATE THIS AFTN INTO THIS EVENING. IT MIGHT HAVE BEEN IDEAL
TO HAVE HAD A START TIME OF THE WARNING AN HOUR OR TWO EARLIER
OVER THE FAR S...BUT NOT SURE THAT SMALL A CHANGE WOULD REALLY
HAVE MEANING AT THIS POINT. HAVE HIGHLIGHTED MY BEST GUESS AT
TIMING WITH SHARP POP GRADIENT IN THE GRIDS...AND IN AN SPS.
CONSIDERED THE POSSIBILITY OF GETTING BLIZZARD CONDITIONS IN E-C
WI FOR A TIME DURING THE LATE AFTN/EVENING. BUT HAVE SEEN SEVERAL
SITNS WITH TEMP PROFILES HAVING A DEEP NEAR FREEZING LAYER WHERE
SNOWFLAKES TEND TO STICK TOGETHER...SO VSBYS DON/T GO DOWN AS MUCH
AS NORMALLY ASSOCIATED WITH INCH AN HOUR SNOWS. GIVEN THE STRENGTH
OF THE DYNAMICS...A FEW RUMBLES OF THUNDER ALSO NOT OUT OF THE
QUESTION.
SNOWS WILL TAPER OFF FM S-N OVERNIGHT. SCT SHSN AND AREAS OF FZDZ
/DUE TO LOSS OF MID-LVL MOISTURE/ WL CONT INTO TUESDAY. IT/S
POSSIBLE A MESO-SCALE SNOW BAND COULD SET UP SOMEWHERE AND
PRODUCE ANOTHER 2-4 INCHES OF SNOW. DON/T KNOW FOR SURE IF/WHERE
THAT WOULD HAPPEN...BUT MOST CONCERNED ABOUT N-C WI DURING THE
AFTN AS DEFORMATION ZONE ON THE NW FLANK OF REMNANTS OF MID-LVL
CIRCULATION WL BE LINGERING IN THAT REGION.
.LONG TERM...TUESDAY NIGHT THROUGH SUNDAY
ISSUED AT 351 AM CST MON DEC 28 2015
ANOTHER UPPER LEVEL SYSTEM WILL CROSS THE AREA LATE TUESDAY NIGHT
INTO WEDNESDAY EVENING. MOISTURE WILL BE MUCH MORE LIMITED...BUT
THE SYSTEM COULD BRING SOME LIGHT SNOWS TO THE AREA.
COLDER AIR WILL SETTLE INTO THE AREA BEHIND THAT SYSTEM. HIGH
TEMPS WL BE NEAR OR MAYBE A LITTLE BELOW NORMAL. MIN TEMPS WILL
DEPEND ON CLOUD COVER. WITH A FRESH DEEP SNOWCOVER...ANY NIGHTS
WITH CLEAR SKIES AND LGTS WINDS COULD GET QUITE COLD.
&&
.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1113 AM CST MON DEC 28 2015
A LARGE AND STRONG LOW PRESSURE SYSTEM WILL MOVE ACROSS THE FORECAST
AREA FROM THE CENTRAL MISSISSIPPI VALLEY THIS AFTERNOON THROUGH
MIDDAY TUESDAY. A LARGE PRECIPITATION SHIELD WILL SURGE NORTHWARD
AHEAD OF THE LOW...REACHING THE SOUTHERN FOX VALLEY BY 19Z AND
NORTHERN WI BETWEEN 00Z-02Z. A MIXTURE OF SNOW AND SLEET IS LIKELY
FROM SUE TO ISW SOUTHWARD. STRONG GUSTY NE WINDS UP TO 40 KTS WILL
CREATE BLOWING AND DRIFTING OF THE NEW SNOW. AS THE SNOW WINDS DOWN
LATE TONIGHT...FREEZING DRIZZLE WILL MIX IN WITH THE SNOW THROUGH
THE END OF THE TAF PERIOD. WINDS WILL ALSO DIMINISH TOMORROW
MORNING.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL 6 AM CST TUESDAY FOR WIZ045-048>050.
WINTER STORM WARNING FROM 3 PM THIS AFTERNOON TO 6 AM CST
TUESDAY FOR WIZ030-031-035>040.
WINTER STORM WARNING FROM 6 PM THIS EVENING TO 9 AM CST TUESDAY
FOR WIZ005-010>013-018>022-073-074.
&&
$$
UPDATE.........SKOWRONSKI
SYNOPSIS.......SKOWRONSKI
SHORT TERM.....SKOWRONSKI
LONG TERM......ECKBERG
AVIATION.......MPC
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
404 PM MST MON DEC 28 2015
.SHORT TERM...(TONIGHT THROUGH WEDNESDAY NIGHT)
ISSUED AT 339 PM MST MON DEC 28 2015
BROAD UPPER-LEVEL TROUGHING WILL REMAIN IN PLACE ACROSS THE CENTRAL
ROCKIES OVER THE NEXT SEVERAL DAYS. SURFACE HIGH PRESSURE WILL HELP
KEEP THINGS ON THE DRY SIDE THROUGH THURSDAY. HOWEVER...A FEW SHOTS
OF MID-LEVEL ENERGY COMBINED WITH INSTABILITY ALOFT MAY YIELD A FEW
MOUNTAIN SNOW SHOWERS OR FLURRIES OVER THE PLAINS. OTHERWISE...COLD
TEMPERATURES CONTINUE. ANOTHER VERY TRICKY TEMPERATURE FORECAST FOR
TONIGHT WITH CLOUDS INCREASING FROM THE SOUTHWEST. HOWEVER...TO SAY
MODELS ARE DOING POORLY IS AN UNDERSTATEMENT. THE LATEST MET WAS 10
DEGREES TOO WARM AT 21Z AT LARAMIE. A SIMILAR STORY CAN BE SAID FOR
THE HIGH PLAINS WITH LINGERING SNOWPACK...SO OPTED TO GIVE A NOD TO
THE COLDER END OF THE MOS SPECTRUM. NOT THINKING THE INCOMING CLOUD
COVER WILL IMPACT LOWS MUCH...TEMPERATURES SEEMED TO RISE JUST FINE
UPSTREAM THIS AFTERNOON. WIND CHILLS WILL BE A CONCERN WITH LOWS AS
LOW AS -15 F FOR SOME AREAS. HOWEVER...GENERALLY EXPECT WINDS TO BE
LESS THAN 5 MPH SO OPTED NOT TO ISSUE ANY HEADLINES RIGHT NOW. WILL
LET THE EVENING SHIFT MONITOR THE SITUATION FURTHER. NAM/GFS BUFKIT
SOUNDINGS SHOW LOW T/TD SPREADS OVER MUCH OF THE PLAINS...SO WE MAY
SEE ANOTHER ROUND OF SHALLOW FOG LATE TONIGHT. THIS GENERAL PATTERN
WILL REMAIN IN PLACE THROUGH MID WEEK. THE COLDEST TEMPERATURES ARE
EXPECTED TO BE WED NIGHT/THU AM WITH GFS 700 MILLIBAR TEMPS AS COLD
AS -17 DEG C OVER THE CWA.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 345 PM MST MON DEC 28 2015
THE MAIN STORY THROUGH THE LONG TERM FORECAST PERIOD REMAINS THE
COLD TEMPERATURES. A BROAD AREA OF SURFACE HIGH PRESSURE WILL
REMAIN IN PLACE OVER THE REGION THROUGH FRIDAY BEFORE SLIDING EAST
INTO THE PLAINS THIS WEEKEND.
FOR THURSDAY AND FRIDAY...HIGH TEMPERATURES WILL BE IN SINGLE
DIGITS TO TEENS ACROSS SOUTH CENTRAL WYOMING...WHILE 20S WILL BE
FOUND ACROSS FAR SOUTHEAST WYOMING AND WESTERN NEBRASKA PANHANDLE.
LOW TEMPERATURES WILL MAINLY BE IN THE SINGLE DIGITS BELOW ZERO TO
TEENS BELOW OVER SOUTH CENTRAL WYOMING...WITH SINGLE DIGITS ABOVE
ZERO INTO FAR SOUTHEAST WYOMING AND NEBRASKA PANHANDLE. TEMPERATURES
SHOULD BEGIN TO WARM BY THE WEEKEND...GENERALLY WARMING 5 TO 10
DEGREES ON SATURDAY AND ANOTHER 5 DEGREES BY SUNDAY.
AT THIS POINT NOT ANTICIPATING MEASURABLE PRECIPITATION THROUGH
THE WEEKEND...WITH THE POSSIBLE EXCEPTION BEING THE MOUNTAINS.
A FEW WEAK UPPER LEVEL DISTURBANCES WILL MOVE OVER THE AREA LATE
THIS WEEK BUT ANY SNOW ACCUMULATIONS SHOULD BE CONFINED TO THE
MOUNTAINS WITH ONLY AN INCH OR TWO OF ACCUMULATION. ELSEWHERE
LOOKING AT SNOW FLURRIES IF ANYTHING AT ALL.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 400 PM MST MON DEC 28 2015
TRICKY AND UNCERTAIN FORECAST FOR OUR SOUTHEAST WYOMING AND
NEBRASKA PANHANDLE AIRPORTS TONIGHT. DID GET IFR/LIFR GROUND FOG
THIS MORNING AND SEE NO REASON WHY IT WOULD NOT HAPPEN AGAIN
TONIGHT. HRRR IS SHOWING THIS EARLY THIS EVENING. ITS ALSO SHOWING
IFR/LIFR FOR KCYS...BUT GIVEN THE WESTERLY DOWNSLOPE WIND
DIRECTION FORECAST...DO FEEL THIS MAY BE OVERDONE. DO THINK OUR
WESTERN NEBRASKA AIRPORTS WILL SEE FOG TONIGHT AND HAVE LOWERING
CONDITIONS IN THE 00Z TAFS. FOG COULD PERSIST THROUGH MUCH OF THE
MORNING GIVEN THE LIGHT WINDS. WILL CONTINUE TO MONITOR.
&&
.FIRE WEATHER...
ISSUED AT 143 AM MST MON DEC 28 2015
NO FIRE WEATHER CONCERNS IN THE NEAR FUTURE AS SNOW COVER REMAINS
OVER THE MAJORITY OF THE FORECAST AREA WITH BELOW NORMAL
TEMPERATURES. DAYTIME RELATIVE HUMIDITIES WILL REMAIN BETWEEN 40
TO 60 PERCENT.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...CLH
LONG TERM...SML
AVIATION...GCC
FIRE WEATHER...TJT