Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 01/31/13
AREA FORECAST DISCUSSION
NWS TUCSON AZ
950 PM MST MON JAN 28 2013
.SYNOPSIS...AN UPPER LEVEL SYSTEM OVER WESTERN ARIZONA MONDAY
EVENING WILL PUSH EAST ACROSS THE AREA TONIGHT INTO TUESDAY MORNING.
EXPECT SCATTERED SHOWERS WITH SNOW LEVELS LOWERING DOWN TO AROUND
3500 FEET. MINOR SNOW ACCUMULATIONS ARE POSSIBLE SOUTH AND EAST OF
TUCSON. COLD TUESDAY AND WEDNESDAY MORNING. EXPECT DRY CONDITIONS TO
RETURN THE SECOND HALF OF THE WEEK ALONG WITH WARMER TEMPERATURES.
&&
.DISCUSSION...WATER VAPOR IMAGERY SHOWED UPPER LEVEL TROF AXIS
EXTENDING FROM THE FOUR CORNERS SW TO JUST WEST OF ROCKY POINT. HAVE
HAD SCATTERED LIGHT SHOWERS GOING MOST OF THIS EVENING EAST OF
TUCSON WITH ANOTHER BATCH OF SHOWERS WEST SOUTHWEST OF TUCSON. 00Z
NAM AND RAP MODELS MOVE UPPER LEVEL TROF EAST OVERNIGHT WITH SHOWERS
INCREASING IN AREAL COVERAGE AS TROF ENCOUNTERED A LITTLE MORE
PRECIPITABLE WATER. THE SHOWERS THAT WERE OUT BY YUMA AND ROCKY
POINT EARLIER THIS EVENING HAS FALLEN APART AS THEY HAVE MOVED INTO
SOME DRIER AIR THAT RESIDES OVER CENTRAL PIMA COUNTY WHERE PW VALUES
WERE AROUND 0.35" BASED ON GPS. PW VALUES FROM TUCSON EAST ARE NEAR
A HALF AN INCH. SNOW LEVEL WILL LOWER TO AROUND 3500 FEET OVERNIGHT
WITH UP TO AN INCH ACROSS SANTA CRUZ AND COCHISE COUNTIES.
CONTEMPLATED WINTER WEATHER ADVISORY FOR THOSE COUNTIES BUT HELD OFF
ON ISSUING ONE. IF RADAR LIGHTS UP IN THE NEXT COUPLE OF HOURS THEN
WE MAY HAVE TO HOIST A QUICK ONE. OTHERWISE SENDING OUT ANOTHER
UPDATE TO THE FORECAST.
SYSTEM OUT OF HERE ON TUESDAY WITH STRONG NW FLOW ON BACK SIDE. MAY
SEE PRETTY STRONG WINDS IN NW-SE ORIENTED VALLEYS TUESDAY AFTERNOON.
SPEEDS MAY END UP NEAR ADVISORY CRITERIA.
&&
.AVIATION...BKN-OVC CLOUDS 5-8K FT AGL AND MTNS OBSCD...WITH SCT
-SHRA/SHSN THRU TONIGHT...THEN SKIES GRADUALLY CLEARING TUESDAY
MORNING. WINDS GENERALLY WLY-SWLY 12-22 KTS WITH HIGHER GUSTS EAST
OF TUCSON THROUGH 06Z TUESDAY...THEN MAINLY LESS THAN 10 KTS THROUGH
TUESDAY MORNING FROM KTUS WESTWARD AND 10-20 KTS ACROSS EASTERN
AREAS. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...NO FIRE WEATHER CONCERNS. SCATTERED SHOWERS AND
BREEZY CONDITIONS INTO THIS EVENING. DRY WEATHER TUESDAY BUT WINDY
ESPECIALLY IN THE UPPER GILA RIVER VALLEY. TEMPERATURES WILL BEGIN
TO MODERATE WEDNESDAY WITH DRY CONDITIONS CONTINUING.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY TIL 11 PM TONIGHT FOR AZZ510
&&
$$
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
355 PM MST WED JAN 30 2013
.SHORT TERM...STRONG NORTHWEST FLOW ALOFT OVER AREA WITH
OROGRAPHICS CONTINUING ACROSS MOUNTAINS. WEB CAMS INDICATE SNOW
CONTINUING ACROSS MOUNTAINS...THOUGH HAS SHOWN SOME SIGNS OF
DECREASING DURING THE PAST FEW HOURS. STABILITY HAS BEEN
LIMITED...WHICH HAS HINDERED THE HEAVIER SNOW RATES. STILL..WINDS
BEEN QUITE GUSTY ACROSS THE RIDGES...WITH A RECENT GUST TO 71 MPH
ATOP BERTHOUD PASS WHILE OTHER GUSTS WERE MAINLY IN THE 50S. THE
WINDS WERE CREATING AREAS OF BLOWING SNOW ACROSS THE MOUNTAIN
PASSES. GUSTY WINDS ALSO OCCURRING IN AND NEAR FOOTHILLS WITH
GUSTS MAINLY IN THE 40S. ACROSS PLAINS WEAK MESOCYCLONE SLIDING
SOUTH ACROSS MORGAN COUNTY KEEPING GUSTY WINDS FROM SPREADING EAST
ACROSS URBAN CORRIDOR. FLOW ALOFT REMAINS STRONG TONIGHT AND
INCREASES SLIGHTLY AS SHOWN BY RAP CROSS SECTIONS. AIRMASS TO
REMAIN QUITE MOIST ACROSS THE MOUNTAINS ALONG WITH CONTINUED
OROGRAPHICS AND SNOWFALL. STABILITY SHOULD IMPROVE OVERNIGHT...
HELPING WITH SNOWFALL RATES. ADDITIONAL 3 TO 6 INCHES STILL
POSSIBLE ON FAVORED WEST FACING SLOPES WITH LESSER AMOUNTS
ELSEWHERE. MODEL CROSS SECTIONS SHOW WEAK MOUNTAIN WAVE DEVELOPING
OVERNIGHT WHICH WILL HELP TO INCREASE WINDS. GUSTS AROUND 70 MPH
POSSIBLE ALONG THE HIGHER RIDGES...WITH GUSTS UP TO 60 MPH ALONG
THE FOOTHILLS. THE GUSTY WINDS WILL CONTINUE TO CREATE CONSIDERABLE
BLOWING SNOW OVER THE MOUNTAIN PASSES WITH POSSIBLE WHITE OUT
CONDITIONS ABOVE TIMBERLINE. ACROSS PLAINS...WINDS TO BE A BIT
GUSTY NEAR THE FOOTHILLS AND WYOMING BORDER WITH LESS WIND
ELSEWHERE. MODELS CONTINUE TO SHOW AN AREA OF LIGHT SNOW
DEVELOPING ALONG THE WYOMING BORDER TONIGHT IN VICINITY OF UPPER
JET. OTHERWISE...DRY CONDITIONS TO PREVAIL. ON THURSDAY...STRONG
NORTHWEST FLOW ALOFT TO CONTINUE THOUGH MODEL CROSS SECTIONS
INDICATE MOISTURE ACROSS MOUNTAINS DECREASING BY THE AFTERNOON AS
STABILITY INCREASES. STILL DECENT ORORGRAPHICS IN PLACE FOR MUCH
OF THE DAY ALONG WITH GUSTY WINDS. SHOULD SEE SNOW GRADUALLY
DECREASE DURING THE DAY THOUGH THERE WILL STILL BE QUITE A BIT OF
BLOWING SNOW. WILL MAINTAIN THE WARNING THROUGH THE DAY THOUGH
ADDITIONAL SNOWFALL SHOULD BE LIGHT. WINDS TO BE A BIT GUSTY IN
AND NEAR THE FOOTHILLS AS A WEAK SURFACE TROUGH IS EXPECTED TO
DEVELOP. FURTHER EAST...MODELS CONTINUE TO SHOW A WEAK COLD FRONT
MOVING INTO THE NORTHEAST CORNER. WITH UPPER JET IN VICINITY...
THERE COULD BE A SLIGHT CHANCE OF LIGHT SNOW IN THE FAR NEAR THE
WYOMING BORDER. OTHERWISE DRY CONDITIONS WILL PREVAIL.
.LONG TERM...A RATHER BENIGN WEEK OF WEATHER IS EXPECTED AFTER THE
SNOW SHOWERS CLEAR OUT OF THE MOUNTAINS THURSDAY NIGHT. ON
THURSDAY EVENING...A FEW SNOW SHOWERS MAY BE LINGERING...BUT THEY
WILL BE ON THE DECREASE AS SUBSIDENCE OVER THE STATE INCREASES.
DRY...NORTHWESTERLY FLOW ALOFT IS FORECAST TO CONTINUE THROUGH
THE PERIOD AS AN UPPER RIDGE REMAINS ANCHORED OFF THE WEST COAST
AND A DEEP TROUGH CONTINUES OVER THE EASTERN UNITED STATES. THE
ECMWF AND GFS ARE IN GOOD AGREEMENT THROUGH THE WEEKEND...BUT AT
THE END THE TWO MODELS HAVE DIFFERENT IDEAS ABOUT A TROUGH THAT
DEVELOPS OFF THE CALIFORNIA COAST. IF A TROUGH DEVELOPS...IT IS
NOT EXPECTED TO MOVE INTO THE CENTRAL ROCKIES UNTIL THE MIDDLE OF
NEXT WEEK. TEMPERATURES SHOULD GRADUALLY MODERATE THROUGH THE
UPCOMING FORECAST PERIOD AS THE NORTHWEST FLOW ALOFT CONTINUES.
&&
.AVIATION... WINDS HAVE BECOME LIGHT NORTHEAST AT DEN DUE TO WEAK
MESOCYCLONE OVER MORGAN COUNTY. GUSTY WEST TO NORTHWEST WINDS
CONTINUE AT APA AND BJC. WINDS TO BECOME NORTHWEST AT DEN BY 00Z
AS MESOCYCLONE SHIFTS EAST INTO WASHINGTON COUNTY. AFTER
03Z...WINDS SHOULD SHIFT TO THE SOUTHWEST AT DEN AND APA AS
DRAINAGE FLOW DEVELOPS WITH SPEEDS AROUND 12 KTS. WINDS TO REMAIN
WEST TO NORTHWEST AT BJC THROUGH THE EVENING AND OVERNIGHT...WITH
SOME GUSTS TO 40 KTS POSSIBLE AFTER 06Z. ON THURSDAY...WINDS
TO BECOME NORTHWEST AND WEAKEN ACROSS THE AREA AFTER 16Z. SOME
GUSTS TO 25 KTS WILL BE POSSIBLE AT BJC. VFR TO PREVAIL.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL 5 PM MST THURSDAY FOR COZ031-033-034.
&&
$$
SHORT TERM...D-L
LONG TERM....DANKERS
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS PUEBLO CO
302 PM MST TUE JAN 29 2013
.SHORT TERM...
(TONIGHT AND WEDNESDAY)
SNOW HAS BEEN WINDING DOWN ACROSS THE SOUTHEAST MOUNTAINS/I-25
CORRIDOR AS FOCUS FOR HEAVIER SNOW SHIFTS EASTWARD ACROSS THE PLAINS
AHEAD OF THE MAIN UPPER TROF AXIS. SNOWFALL REPORTS THAT HAVE COME
IN SO FAR HAVE INDICATED 2 TO 5 INCHES ACROSS THE LOWER EASTERN
SLOPES OF THE SE MTS AND ADJACENT I-25 CORRIDOR. GOBBLERS KNOB WEB
CAM IN SOUTHERN PROWERS COUNTY STARTING TO PICK UP SOME HEAVIER SNOW
AS OF 2 PM...WITH GROUND NEARLY SNOW COVERED.
FOCUS FOR HEAVIER SNOW WILL CONTINUE TO SHIFT SOUTH AND EASTWARD
THROUGH THE LATE AFTERNOON AND EARLY EVENING. STILL THINKING
GENERALLY 1-3 INCHES OF SNOWFALL FOR THE SOUTHEAST PLAINS GENERALLY
TO THE SOUTH AND EAST OF KLHX. THE HEAVIEST WILL FALL ALONG THE
NORTHERN SLOPES OF THE RATON MESA AND ACROSS BACA COUNTY. WHILE 18Z
NAM CONTINUES TO DEPICT A BAND OF HEAVIER SNOW AMOUNTS OF 1 TO 3
INCHES ACROSS BACA/LAS ANIMAS...THE RAP HAS BACKED OFF ON THIS AND
NOW PLACES THE BAND WELL TO THE SOUTH OF THE AREA. HRRR ALSO
APPEARS TO HAVE BACKED OFF ON SNOW AMOUNTS ACROSS BACA COUNTY...SO
WILL HOLD OFF ON ISSUING ANY HIGHLIGHTS AT THIS POINT AND STICK WITH
THE GENERALLY 1-3 INCH AMOUNTS. WITH INSTABILITY STILL IN PLACE WITHIN THE
TROF AXIS...THERE STILL COULD BE SOME LINGERING SNOW SHOWERS BEHIND
THE TROF AXIS THROUGH THE EVENING...THUS WILL KEEP SCATTERED POPS IN
AND NEAR THE MOUNTAINS UNTIL 06Z.
MEANWHILE...ALTHOUGH HEAVIER SNOW WILL BE TAPERING
OFF...NORTHWESTERLY OROGRAPHICS AND INCREASING WINDS ALOFT ON THE
BACK SIDE OF THE UPPER TROF WILL KEEP WIDESPREAD LIGHT TO MODERATE
SNOW GOING ALONG THE SAWATCH AND MOSQUITO RANGES THROUGH THE
NIGHT...WITH THE WIND CAUSING SOME AREAS OF BLOWING SNOW. WITH
TEMPERATURES FALLING INTO THE NEGATIVE READINGS OVERNIGHT...MAY ALSO
SEE SOME WIND CHILL ADVISORY READINGS IN THE -25 TO -34 DEGREE
RANGE. PREVIOUS SHIFT ISSUED A LONG DURATION WINTER WEATHER
ADVISORY FOR THIS AREA...AND THIS STILL LOOKS GOOD...THOUGH HIGHEST
IMPACT MAY BE DUE TO MORE BLOWING SNOW INITIALLY. WILL ADD MENTION
OF THE WIND CHILL VALUES TO THE UPDATED WSW. MAY ALSO SEE WIND
CHILL ADVISORY VALUES ACROSS THE HIGHER ELEVATIONS OF THE EASTERN
SAN JUAN AND LA GARITA MOUNTAINS...THOUGH GIVEN THE SPOTTY NATURE
WILL HOLD OFF ON ISSUING A WIND CHILL ADVISORY AT THIS POINT.
TRAILING SHORTWAVE ENERGY DROPPING IN ON WEDNESDAY SHOULD ENHANCE
SNOWFALL AGAIN ACROSS THE CENTRAL MOUNTAINS WEDNESDAY AFTERNOON.
SHOULD SEE 24 HOUR ACCUMULATIONS OF 2 TO 8 INCHES THROUGH WEDNESDAY
AFTERNOON FOR THIS AREA. ELSEWHERE WX WILL BE PRIMARILY DRY. GUSTY
NORTHWEST 20-40 MPH WINDS WILL MIX DOWN INTO THE LOWER ELEVATIONS
AND ADJACENT I-25 CORRIDOR WEDNESDAY AFTERNOON WHERE GUSTS TO AROUND
20-30 MPH WILL BE POSSIBLE. SNOW COVER WOULD BODE FOR KEEPING TEMPERATURES
ON THE COOL SIDE OF GUIDANCE TOMORROW...THOUGH WITH THE WINDS AND
SOME MIXING...THEY SHOULD MANAGE TO WARM ABOVE FREEZING ACROSS MOST
OF THE PLAINS. LEANED MAX TEMPS TOWARDS THE COOLER SIDE OF GUIDANCE
FOR NOW. MOUNTAIN AREAS WILL SEE HIGHS GENERALLY IN THE TEENS
AND 20S...WITH SOME LOWER 30S ACROSS THE VALLEY AREAS. -KT
.LONG TERM...
(WEDNESDAY NIGHT THROUGH TUESDAY)
WEDNESDAY NIGHT AND THURSDAY...BRISK NW FLOW ALOFT CONTINUES ACROSS
THE REGION THROUGH THURSDAY...WITH MODELS AGREEING ON KEEPING A NEARLY
CONSTANT THREAT OF LIGHT TO MODERATE PCPN OVER THE CENT MTS THROUGH
THE EVE. THOUGH NEW SNOW AMOUNTS WILL ACCUMULATE TO 12 TO 16
INCHES BY THURSDAY AFTN...ANOTHER REAL CONCERN WILL BE THE STRONG
WINDS ALOFT THAT WILL BE EXPERIENCED ACROSS THE HIGHER TERRAIN. A
100 KT CORE OF THE UPPER JET NOSES INTO THE NW QUAD OF COLORADO
THROUGH WEDNESDAY NIGHT...BEFORE MOVING EAST AND WINDS WEAKEN BY
MIDDAY THURSDAY. THEREFORE...ONGOING WINTER WX ADV FOR THE HIGHER
ELEVATIONS OF LAKE AND CHAFFEE COUNTIES LOOKS GOOD. MAX TEMPS ON
THURSDAY ARE EXPECTED TO REBOUND INTO THE 50S FOR THE PLAINS...30S
AND 40S FOR THE HIGH VALLEYS.
FRIDAY AND SATURDAY...TEMPORARY RIDGING ACROSS THE DESERT SW AND
COLORADO TO START THE WEEKEND...WITH DRY AND MILD CONDITIONS
EXPECTED. MODELS DO INDICATE A MINOR UPPER DISTURBANCE ROLLING
ACROSS THE ROCKY MT REGION...BUT CONTINUE TO KEEP THIS FEATURE JUST
NORTH OF THE CWA AND FEEL THAT THE ONLY EFFECT WILL BE AN INCREASE
IN HIGH LEVEL CLOUDINESS. WINDS REMAIN SOMEWHAT LIGHT...SO NO
APPRECIABLE CHANGE IN THE TEMPS IS EXPECTED.
SUNDAY THROUGH TUESDAY...AN UPPER LOW PRES SYSTEM JUST OFF THE S CA
COAST WILL START PUSHING A PLUME OF WARMER PACIFIC MOISTURE UP
ACROSS AZ AND THE 4 CORNERS STARTING ON SUNDAY. AT THE SAME TIME...AN
UPPER DISTURBANCE DROPPING DOWN ACROSS MT AND WY WILL ACT UPON THIS
MOISTURE TAP AND SQUEEZE OUT SOME ISOLATED SHOWERS ALONG THE CONTDVD
LATE SUNDAY. AS THIS FEATURE MOVES EAST AND OUT OF THE
AREA MONDAY...PCPN CHANCE DIMINISH. HOWEVER...LATE MONDAY THE LOW
OFF THE WEST COAST STARTS TO FILL AND MOVE ONSHORE...BRINGING A
SHOT FOR PCPN ONCE AGAIN TO THE CONTDVD STARTING TUESDAY MORNING.
MOORE
&&
.AVIATION...
VFR CIGS ACROSS THE TAF SITES WILL GRADUALLY DIMINISH THROUGH THE
EVENING. THERE COULD BE A LIGHT SNOW SHOWER IN THE VICINITY OF KCOS
THIS EVENING...THOUGH CHANCE LOOKS TOO REMOTE TO WARRANT INCLUSION
IN THE TAF AT THIS POINT. WINDS WILL DECREASE TO UNDER 6 KTS AT KPUB
AND KALS OVERNIGHT...THOUGH KCOS MAY CONTINUE TO SEE SOME ENHANCED
NORTH WINDS IN THE 5-10 KT RANGE THROUGH THE NIGHT.
MEANWHILE...IFR TO LIFR CIGS AND VIS IN -SHSN WILL CONTINUE ALONG
THE CONTDVD...PARTICULARLY ACROSS THE CENTRAL MTS...RESULTING IN
WIDESPREAD MTN OBSCURATIONS. MVFR TO BRIEFLY IFR CIGS WILL CONTINUE
ACROSS THE SOUTHEAST PLAINS THROUGH EARLY EVENING BEFORE THE SNOW
BAND PUSHES SOUTHEAST OF THE AREA OVERNIGHT.
ON WEDNESDAY...VFR CIGS/VIS EXPECTED FOR THE TAF SITES...WITH SOME
BREEZY WEST TO NW WINDS 10-15 KTS POSSIBLE AT KCOS AND KPUB DURING
THE AFTERNOON. -KT
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 5 PM MST THURSDAY FOR COZ058-060.
&&
$$
31/27
AREA FORECAST DISCUSSION...UPDATED
NWS PUEBLO CO
1119 AM MST TUE JAN 29 2013
.UPDATE...
QUICK UPDATE TO INCREASE POPS FARTHER EAST AND TO DECREASE POPS TO
THE NORTH AND WEST. DISTINCT BACK EDGE TO THE SNOW BAND IS DROPPING
SOUTHWARD INTO NRN PUEBLO COUNTY...AND SNOW IS LIGHTENING UP ALONG
THE LEE OF THE WET MOUNTAINS. ALREADY HAD REPORTS OF 1 TO 3
INCHES FOR EL PASO AND PUEBLO COUNTIES...WITH AROUND 5 INCHES
REPORTED AT BEULAH...AND 4 INCHES AROUND 5 MILES WEST OF
WALSENBURG. THE LOWER EASTERN SLOPES OF THE SE MTS...WETS AND
SANGRES...COULD PICK UP ANOTHER INCH OR TWO...WITH GREATEST
AMOUNTS ACROSS THE SOUTHERN SANGRES AREAS DURING THE EARLY
AFTERNOON. MAIN CONCERN IS SHIFTING TO THE SOUTHEAST PLAINS. SOME
OF THE HIGH RES SHORT RANGE MODELS DEPICT A BAND OF 2 TO 4 INCHES
ACROSS BACA COUNTY LATER THIS AFTERNOON...THOUGH RAP IS KEEPING
THIS AXIS TO THE SOUTH OF THE AREA. COULD HIT LOW END ADVISORY
THRESHOLDS OUT THAT WAY...BUT BREVITY OF THE STORM MAY LIMIT
SNOWFALL ACCUMS TO JUST BELOW CRITERIA AS THE SYSTEM PULLS EAST OF
THE AREA AFTER 00Z. LAPSE RATES ARE QUITE IMPRESSIVE...WHICH IS
WHY SNOWFALL HAS BEEN HEAVY AT TIMES. INSTABILITY IS ALWAYS A WILD
CARD IN SCENARIOS LIKE THIS ONE AND CAN RESULT IN LOCALLY HEAVY
SNOWFALL AMOUNTS. WILL CONTINUE TO MONITOR AND MAKE ADJUSTMENTS TO
THE FORECAST AS NEEDED. -KT
&&
.PREV DISCUSSION... /ISSUED 1030 AM MST TUE JAN 29 2013/
AVIATION...
FOR KCOS...SNOW HAS ENDED. CONDITIONS WILL IMPROVE TO VFR.
KPUB...SNOW EXPECTED TO CONTINUE THROUGH ABOUT 19Z AND THEN
DIMINISH. IFR/LIFR UNTIL AROUND 19Z...AND THEN GRADUALLY IMPROVING
TO VFR.
KALS...SNOW SHOWERS WILL BE POSSIBLE THROUGH THE DAY WITH POSSIBLE
MVFR CONDITIONS.
SNOW SHOWERS WILL CONTINUE IN THE MOUNTAINS WITH ISOLATED TO SCATTERED
MVFR/IFR/LIFR CONDITIONS.
THE HEAVIEST SNOW IS YET TO COME FOR THE FAR SOUTHEAST COLORADO
PLAINS...SOUTH AND EAST OF PUEBLO. SNOWFALL EXPECTED TO INCREASE
IN THAT AREA THROUGH THE AFTERNOON WITH SNOW...BLOWING SNOW AND AT
LEAST A FEW INCHES OF ACCUMULATION POSSIBLE. EXPECTING MVFR/IFR/LIFR
CONDITIONS TO DEVELOP ACROSS THE FAR SOUTHEAST PLAINS THIS
AFTERNOON AS SNOWFALL MOVES INTO THE AREA. LW
PREV DISCUSSION... /ISSUED 341 AM MST TUE JAN 29 2013/
SHORT TERM...
(TODAY AND TONIGHT)
.SOME SNOW FOR THE PLAINS...
.SNOW CONTINUING ACROSS THE C MTNS...
CURRENTLY...
FULL LATITUDE TROUGH EXTENDS FROM NORTHERN WY S-SWD INTO S ARIZ.
THIS TROUGH WAS MOVING STEADILY EAST. LOCALLY ON THE PLAINS...ECHOES
WERE INCREASING ACROSS EL PASO COUNTY WITH HIGH LEVEL ECHOES
DEVELOPING OVER THE FAR E PLAINS. SKIES WERE GENERALLY CLOUDY OVER
THE ENTIRE REGION WITH LOW CLOUDS ALONG THE GREATER I-25 CORRIDOR
REGION.
TODAY...
IT PROMISES TO BE AN INTERESTING DAY...HOW INTERESTING WILL BE THE
MAIN QUESTION.
I AM CONFIDENT WE WILL SEE SNOW ACROSS THE PLAINS TODAY. MODELS IN
FAIRLY GOOD AGREEMENT WITH SNOW DEVELOPING THIS MORNING OVER THE
PALMER DIVIDE (AND THIS IS VERIFYING) AND MOVING S/DEVELOPING OVER
THE EASTERN PLAINS AFTER SUNRISE. SHORTER RANGE MODELS ARE NOW
DEVELOPING A SHARP TROUGH AXIS/WEAK CLOSED LOW AT 700 MB OVER THE
FAR SE PLAINS REGION OF CO. THIS WILL SET UP STRONGER LLVL
CONVERGENCE OVER THE E PLAINS AND THIS SHOULD ALLOW A DECENT BAND OF
SNOW TO DEVELOP...WITH THE HEAVIEST PRECIP LIKELY EXTENDING FROM EADS
SSW TOWARDS LAS ANIMAS COUNTY. ADDITIONALLY...WITH THE SHARP LLVL
TROUGH...WINDS AT 700 GO NORTHEASTERLY AND THIS SHOULD FAVOR THE
RATON MESA/S MTNS LATER TODAY. THE COS/PUB AREAS WILL SEE ITS BEST
CHANCE OF SNOW FROM NOW THROUGH LATE MORNING. AS FOR
ACCUMULATIONS...WE COULD SEE 1-2" IN AREAS IN THE PUB/COS AREA. IN
MATTER OF FACT...SOME OF THE HIGH RES MODELS ARE SHOWING MORE SNOW
FOR THE PUB AREA THAN THE SPRINGS. FOR THE FAR E PLAINS...I PUT IN
1-2"...I AM CONCERNED THERE MAY BE LOCALLY MORE IF THE SNOW COMES
DOWN HEAVY ENOUGH. RATON MAY SEE 1-3".
THESE VALUES ARE SOMEWHAT UNCERTAIN...ESPECIALLY FOR THE FAR E
PLAINS. IF THE BAND SETS UP AND STAYS IN PLACE...WE COULD SEE
LOCALLY HIGHER AMOUNTS OVER THE FAR E PLAINS...ESPECIALLY IN AREAS
FROM KIOWA COUNTY S-SE INTO LAS ANIMAS COUNTY.
SNOW OVER THE CONTDVD WILL DECREASE THIS MORNING...ESPECIALLY ACROSS
THE SW MTNS. THE SNOW WILL PICK UP AGAIN ACROSS THE C MTNS THIS
AFTERNOON.
TONIGHT...
PLAINS WILL BE DRY. THERE MAY BE A FEW LINGERING SHOWERS EARLY THIS
EVENING OVER THE FAR E PLAINS...BUT THEY SHOULD MOVE OUT INTO KS
PRETTY QUICKLY. IN ADDITION...WE MAY SEE SOME LINGERING SNOW SHOWERS
OVER THE PALMER DIVIDE DURING THE EVENING HOURS.
FOR THE C MTNS...SNOW WILL CONTINUE TO INCREASE. WE WILL BE ISSUING
ADDITIONAL HILITES FOR THIS REGION AFTER 5 AM THIS MORNING. WE ARE
LEANING TOWARDS A LONG DURATION HILITE STARTING LATER TODAY AND
LASTING POSSIBLY INTO LATE WEEK (THU?). FAVORABLE NW FLOW WILL KEEP
THE SNOW MACHINE GOING FOR AT LEAST A COUPLE OF DAYS ACROSS THE C
MTN REGION. /34
LONG TERM...
(WEDNESDAY THROUGH TUESDAY)
MODELS IN GOOD AGREEMENT HEADING INTO THE WEEKEND WITH DIFFERENCES
BY EARLY NEXT WEEK. TRENDED THE FORECAST WITH THE ECMWF WHICH
SEEMS TO HAVE A BIT BETTER SUPPORT OF THE ENSEMBLE MEMBERS.
THE UPPER LEVEL TROUGH SITTING OVER EASTERN COLORADO WEDNESDAY
MORNING WILL QUICKLY SHIFT EAST INTO THE MISSOURI VALLEY BY
WEDNESDAY AFTERNOON. BOTH THE ECMWF AND NAM HAVE SNOW COMING TO AN
END OVER THE PALMER DIVIDE AND SOUTHERN SANGRE DE CRISTO RANGE
BEFORE SUNRISE WEDNESDAY...WHILE THE GFS WANTS TO HANG ONTO
LINGERING SNOW OVER THESE AREAS THROUGH MUCH OF WEDNESDAY MORNING.
GIVEN THAT THE MODELS SEEM TO FAVOR DRY CONDITIONS...HAVE THE
EASTERN MOUNTAINS AND PALMER DRY BY WEDNESDAY MORNING. ONCE THE
UPPER TROUGH SHIFTS EAST WEDNESDAY AFTERNOON...THE REGION WILL BE
UNDER BROAD NORTHWESTERLY FLOW. EXPECT A PROLONGED PERIOD OF LIGHT
TO MODERATE SNOWFALL ACROSS THE CENTRAL MOUNTAINS THROUGH
THURSDAY. WEST FACING SLOPES WILL LIKELY SEE A GOOD 4 TO 8 INCHES
WEDNESDAY THROUGH THURSDAY WITH LOCALLY HIGHER AMOUNTS POSSIBLE.
WINTER WEATHER HIGHLIGHTS WILL LIKELY BE ISSUED FOR THE HIGHER
ELEVATIONS OF THE CENTRAL MOUNTAINS LATER THIS MORNING.
TEMPERATURES WILL BE COOL ON WEDNESDAY WITH 40S FOR THE LOWER
ELEVATIONS BEFORE REBOUNDING INTO THE MID 50S ON THURSDAY.
NORTHWEST FLOW TURNS MORE WESTERLY THURSDAY NIGHT AHEAD OF A WEAK
SHORTWAVE TROUGH DROPPING SOUTH OUT OF THE NORTHERN ROCKIES. THIS
SHOULD EFFECTIVELY SHUT DOWN SNOWFALL OVER THE CENTRAL MOUNTAINS
BY THURSDAY EVENING. MODELS HANDLE THE WEAK SHORTWAVE DIFFERENTLY.
THE GFS DROPS THE WAVE SOUTH ACROSS COLORADO ON FRIDAY WITH A
PERIOD OF LIGHT SNOWFALL ACROSS THE HIGHER ELEVATIONS FRIDAY
EVENING. THE ECMWF PROVIDES A GLANCING BLOW ACROSS NORTHERN
COLORADO AND KEEPS THE REGION DRY. GIVEN THE CONSISTENCY FROM RUN
TO RUN OF THE ECMWF...HAVE TRENDED WITH IT...WITH DRY CONDITIONS
ON FRIDAY AND FRIDAY NIGHT.
FOR THE LATER HALF OF THE FORECAST PERIOD...HAVE TRENDED WITH THE
ECMWF WHICH HAS BETTER SUPPORT FROM THE ENSEMBLES. HIGH PRESSURE
WILL SHIFT EAST ACROSS COLORADO SATURDAY INTO SUNDAY BEFORE A WEAK
TROUGH OUT OF THE PACIFIC NORTHWEST TRACKS ACROSS THE REGION
SUNDAY NIGHT INTO MONDAY MORNING. TEMPERATURES SHOULD WARM NICELY
FOR THE WEEKEND WITH AT LEAST UPPER 50S TO LOWER 60S ACROSS THE
PLAINS. THERE IS VERY LITTLE MOISTURE TO WORK WITH AND THE
FORECAST LOOKS TO BE DRY AT THIS POINT. HIGH PRESSURE WILL THEN
REBUILD ACROSS THE ROCKIES BY TUESDAY WITH CONTINUED DRY AND MILD
WEATHER. IT SHOULD BE NOTED THAT THE GFS BRINGS A TROUGH INTO THE
REGION LATE SATURDAY THROUGH SUNDAY NIGHT WITH INCREASED CHANCES
FOR SNOWFALL OVER THE MOUNTAIN AREAS...SPREADING EAST INTO THE
PLAINS AS THE SYSTEM PASSES BY. THERE SEEMS TO BE LITTLE SUPPORT
FOR THIS SOLUTION...AND A QUICK LOOK AT THE NEW 06Z RUN HAS REALLY
BACKED OFF ON PRECIPITATION COMPARED TO THE 00Z SOLUTION AND LOOKS
MORE LIKE THE ECMWF. 88
AVIATION...
FOR KCOS...PERIODS OF SNOW WILL OCCUR UNTIL ABOUT LATE MORNING THEN
VFR. LIGHT ACCUMS...ABOUT AN INCH OR SO...ARE POSSIBLE. IFR
CONDITIONS WILL OCCUR IN STEADY PRECIP. WINDS SHOULD NOT BE TOO MUCH
OF AN ISSUE...NNE AT 10-15 KTS DURING THE SNOW. VFR AFTER NOONTIME.
KPUB...COULD SEE SOME SNOW THIS MORNING AND EARLY AFTERNOON. OVC
MVFR/IFR LIKELY. SHOULD CLEAR UP BY EARLY AFTERNOON WITH VFR
CONDITIONS.
KALS...SNOW SHOWERS WILL BE POSSIBLE THROUGH THE DAY WITH POSSIBLE
MVFR CONDITIONS.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 5 PM THIS AFTERNOON TO 5 PM MST
THURSDAY FOR COZ058-060.
&&
$$
31/27
AREA FORECAST DISCUSSION
NWS MIAMI FL
855 PM EST WED JAN 30 2013
.UPDATE...
COLD FRONT MOVING THROUGH THE PANHANDLE THIS EVENING WILL APPROACH
SOUTH FLORIDA AFTER MIDNIGHT TONIGHT. LOCAL WRF AND HRRR SHOW A
THIN LINE OF SHOWERS APPROACHING THE NORTHWEST PORTIONS OF THE CWA
AROUND 09Z TONIGHT...AND THEN THE LINE SLOWLY MOVING THROUGH THE
REST OF THE REGION THROUGH THE MORNING HOURS. THE CURRENT POP
GRIDS HANDLE THIS WELL...SO NO UPDATES ARE NEEDED. TEMPERATURES
TONIGHT WILL BE WARM...WITH LOWS NEAR 60 TO THE LOWER 70S.
ALTHOUGH WINDS WILL LIKELY FALL BELOW SCA CRITERION OVER THE
LOCAL GULF WATERS THIS EVENING...KEPT THE SCA GOING AS WINDS WILL
INCREASE LATE TONIGHT BEHIND THE FRONT. FOR THE ATLANTIC
WATERS...WILL CANCEL THE SCA SINCE THE WINDS HAVE FALLEN TO AROUND
10-15 KNOTS AND WINDS ARE NOT EXPECTED TO INCREASE TO SCA
CONDITIONS AGAIN UNTIL AFTER 18Z ON THURSDAY.
&&
.PREV DISCUSSION... /ISSUED 628 PM EST WED JAN 30 2013/
AVIATION...VFR WILL PREVAIL, BUT A FEW SHOWERS/BRIEF MVFR WILL BE
POSSIBLE ALONG COLD FRONT EXPECTED TO MOVE ACROSS KAPF AT AROUND
SUNRISE, THEN THE EAST COAST TERMINALS BY MID MORNING THU. CURRENT
WIND OBS ARE SSE BUT ACARS DATA SHOWS SSW JUST ABOVE THE SFC.
VEERED WINDS THROUGH THE NIGHT TO SSW AS FRONT APPROACHES, THEN
TURNED WINDS NW BEHIND THE COLD FRONT THU. GUIDANCE SUGGEST
CLOUDS LIKELY WILL HANG TOUGH BEHIND THE FRONT FOR THE EAST COAST
TERMINALS THROUGHOUT THE DAY THU. BEST PROSPECTS FOR SHOWERS/BRIEF
MVFR CIGS LOOK TO BE 10-15Z THU, EXCEPT 06-12Z AT KAPF. THX CWSU
MIAMI FOR COORDINATION. /GREGORIA
PREV DISCUSSION... /ISSUED 237 PM EST WED JAN 30 2013/
SYNOPSIS...
A COLD FRONT WILL MOVE THROUGH SOUTH FLORIDA THURSDAY
MORNING...ENDING THE ABOVE NORMAL TEMPERATURES AND BRINGING A
SLIGHT CHANCE OF SHOWERS AS IT PASSES. HIGH PRESSURE BUILDS IN
FRIDAY THROUGH THE WEEKEND...WITH SLIGHTLY BELOW NORMAL
TEMPERATURES RISING TO NEAR SEASONAL AVERAGES BY EARLY NEXT WEEK.
SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...
BREEZY CONDITIONS IN PLACE THROUGH FLORIDA AS PRESSURE GRADIENT
BETWEEN THE SUBTROPICAL RIDGE OVER WESTERN ATLANTIC AND SURFACE
COLD FRONT MOVING EASTWARD THROUGH THE DEEP SOUTH INCREASES. SOUTH
WINDS HAVE GUSTED TO NEAR 30 KTS...JUST BELOW WIND ADVISORY
CRITERION. GUSTS MAY DIURNALLY DIMINISH SLIGHTLY...BUT REMAIN HIGH
ENOUGH TO PRECLUDE ANY FOG FORMATION TONIGHT. TEMPERATURES AHEAD
OF THE FRONT CONTINUE TO BE ABOVE NORMAL...WITH READINGS NEAR 80F
ACROSS MOST OF SOUTH FLORIDA.
MODELS HAVE TRENDED A BIT SLOWER FOR FROPA FOR SOUTH FLORIDA. THE
SFC FRONT LOCATED NEAR KPNS NOW WILL TREK ACROSS THE PANHANDLE
THIS EVENING...THEN APPROACH I-4 CORRIDOR OVERNIGHT. IT IS NOT
EXPECTED TO INTRUDE ON NORTHWEST SECTIONS OF OUR CWA UNTIL AROUND
SUNRISE. THUS...WARM AND FAIRLY BREEZY NIGHT IS IN STORE. MINIMA
WILL RANGE FROM AROUND 60F NORTHWEST INTERIOR TO AROUND 70F
ATLANTIC METROS. THE COLD FRONT WILL MOVE ACROSS SOUTH FLORIDA
DURING THE MORNING...ACCOMPANIED BY A FEW SHOWERS. DYNAMICAL
FORCING WILL BE NEGLIGIBLE AND ATMOSPHERE WILL REMAIN FAIRLY
STABLE...BUT LOW-LEVEL CONVERGENCE AND DECENT MOISTURE CONTENT
SHOULD BE SUFFICIENT FOR SCATTERED ACTIVITY ALONG AND IN VICINITY
OF SURFACE BOUNDARY. CAA WILL LAG SEVERAL HOURS BEHIND THE
FRONT...SO HIGH TEMPERATURES WILL STILL REACH M/U70S MOST
LOCATIONS.
SKIES CLEAR AND TEMPERATURES PLUMMET THURSDAY NIGHT...AND DESPITE
LACK OF IDEAL RADIATIONAL COOLING CONDITIONS...ADVECTION SHOULD
SUPPORT MINIMA REACHING BELOW 50F FOR MUCH OF THE INTERIOR...AND
SOME 30S ARE POSSIBLE ACROSS COLLIER...GLADES...AND HENDRY COUNTY.
IT APPEARS DRY LOW LEVELS AND NON-ZERO WIND SPEEDS WILL PREVENT
ANY FROST...BUT THIS WILL BE MONITORED. AFOREMENTIONED WINDS
HOWEVER WILL CREATE WIND CHILL VALUES SOME 5-10 DEGREES LOWER THAN
AMBIENT READINGS...LOW ENOUGH TO POSSIBLY REACH ADVISORY
THRESHOLDS ACROSS MAINLY GLADES AND HENDRY COUNTIES.
TEMPERATURES FRIDAY AND FRIDAY NIGHT WILL BE SLIGHTLY BELOW
NORMAL...WITH L70S FOR MAXIMA AND 40S INLAND/50S COASTAL FOR
MINIMA. HIGH PRESSURE BUILDING SOUTH WILL KEEP SKIES CLEAR...AND
NORTH WINDS WILL GRADUALLY BECOME NORTHEAST AND BECOME QUITE LIGHT
OVERNIGHT FRIDAY. TEMPERATURES ATTM APPEAR JUST ABOVE VALUES THAT
WOULD CAUSE FROST CONCERN AND LACK OF WIND SHOULD PRECLUDE ANY
WIND CHILL CONCERNS.
LONG TERM /SATURDAY THROUGH WEDNESDAY/...
THE EXTENDED PERIOD FROM THIS WEEKEND INTO THE MIDDLE OF NEXT WEEK
LOOKS UNEVENTFUL AND DRY AS SEVERAL MID LEVEL TROUGHS MOVE ACROSS
THE NORTHERN STATES MAINTAINING A WEST TO NORTHWEST FLOW OF DRY
AIR OVER THE FLORIDA PENINSULA AND KEEPING THE MID LEVEL RIDGE
SUPPRESSED TO OUR SOUTHEAST. AS THE TROUGHS MOVE TO OUR NORTH,
THIS WILL ALSO REINFORCE THE SURFACE RIDGING ACROSS THE SOUTHEAST
STATES WHICH IN TURN WILL KEEP THE TEMPERATURES CLOSE TO OR
SLIGHTLY BELOW CLIMATOLOGICAL AVERAGES FOR THE BEGINNING OF FEBRUARY.
AVIATION...
GUSTY SOUTHEASTERLY WINDS WILL CONTINUE THROUGH THE TAF PERIOD AT
ALL SITES. FROPA IS STILL EXPECTED ACROSS THE EAST COAST TERMINALS
BETWEEN 10Z-13Z ACCOMPANIED BY SCATTERED SHOWERS. BRIEF PERIODS OF
MVFR CIGS WILL LIKELY ACCOMPANY ANY SHOWER ACTIVITY BUT SHOULD NOT
BE LONG ENOUGH TO PREVAIL IN THE TAF. WINDS WILL TURN AROUND TO
THE NORTHWEST BEHIND THE FRONT AND REMAIN AT AROUND 10 KNOTS.
MARINE...
WINDS NEAR 20 KTS WITH SOUTHERLY GUSTS TO NEAR 30 KTS WARRANTED
ISSUANCE OF SMALL CRAFT ADVISORY EARLY TODAY...AND THIS WILL
REMAIN IN EFFECT FOR ALL MARINE ZONES OVERNIGHT. STRONG WINDS
BEING INDUCED BY TIGHT PRESSURE GRADIENT IN ADVANCE OF QUICK-
MOVING COLD FRONT. THIS FRONT WILL PASS THROUGH EARLY
FRIDAY...WITH NORTH WINDS LIKELY EXCEEDING ADVISORY THRESHOLD
BEHIND IT. STRONG WINDS AND BUILDING SEAS WILL IMPACT THE WATERS
THURSDAY NIGHT THROUGH AT LEAST FRIDAY...BEFORE SUBSIDING AS HIGH
PRESSURE BUILDS OVERHEAD.
FIRE WEATHER...
NO FIRE WEATHER CONCERNS TODAY. A COLD FRONT WILL RACE THROUGH
SOUTH FLORIDA THURSDAY MORNING...WITH MUCH DRIER AIR MOVING IN IN
ITS WAKE. RELATIVE HUMIDITY VALUES MAY DROP TO NEAR 35 PERCENT
THURSDAY AFTERNOON ACROSS GLADES AND HENDRY COUNTIES AND NORTH
WINDS WILL BE 10 TO 15 MPH OR HIGHER. FORECAST CONDITIONS DONT
SUPPORT ISSUANCE OF FIRE WEATHER WATCH...BUT A FIRE DANGER
STATEMENT HAS BEEN ISSUED THURSDAY. RELATIVE HUMIDITY WILL BE
VERY LOW FRIDAY...BUT WINDS WILL SUBSIDE A BIT. STILL...FIRE
WEATHER HEADLINES ARE LIKELY ON FRIDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 67 75 52 71 / 20 30 - 0
FORT LAUDERDALE 71 79 56 72 / 20 30 - 0
MIAMI 71 80 57 72 / 20 20 - 0
NAPLES 66 71 46 71 / 30 20 - 0
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...SMALL CRAFT ADVISORY UNTIL 7 AM EST THURSDAY FOR BISCAYNE BAY-
COASTAL WATERS FROM DEERFIELD BEACH TO OCEAN REEF, FL OUT
20 NM-COASTAL WATERS FROM JUPITER INLET TO DEERFIELD BEACH,
FL OUT 20 NM-WATERS FROM DEERFIELD BEACH TO OCEAN REEF, FL
EXTENDING FROM 20 NM TO THE TERRITORIAL WATERS OF THE
BAHAMAS-WATERS FROM JUPITER INLET TO DEERFIELD BEACH, FL
EXTENDING FROM 20 NM TO 60 NM.
GM...SMALL CRAFT ADVISORY UNTIL 7 AM EST THURSDAY FOR COASTAL WATERS
FROM CHOKOLOSKEE TO BONITA BEACH, FL OUT 20 NM-COASTAL
WATERS FROM EAST CAPE SABLE TO CHOKOLOSKEE, FL OUT 20 NM-
GULF WATERS FROM CHOKOLOSKEE TO BONITA BEACH, FL EXTENDING
FROM 20 TO 60 NM.
&&
$$
DISCUSSION/MARINE/FIRE...84/AK
AVIATION/RADAR...57/DG
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
627 AM EST TUE JAN 29 2013
...WIDESPREAD DENSE FOG THIS MORNING...
.SYNOPSIS...
ATLANTIC HIGH PRESSURE WILL PREVAIL TONIGHT INTO WEDNESDAY. A
STRONG COLD FRONT WILL APPROACH FROM THE WEST WEDNESDAY...BRINGING
WINDY CONDITIONS AND THE THREAT OF THUNDERSTORMS. AFTER THE COLD
FRONT PUSHES OFFSHORE WEDNESDAY NIGHT...HIGH PRESSURE WILL SUPPORT
COOLER AND DRIER CONDITIONS INTO NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
DENSE FOG ADVISORY ALL ZONES UNTIL 10 AM. HIGH RESOLUTION DATA
SUGGESTS FOG MAY LINGER WELL INTO THE MORNING OVER MUCH OF
INTERIOR SOUTHEAST SOUTH CAROLINA WHICH MAY HAVE AN IMPACT ON HIGH
TEMPERATURES. LATEST RAP SUGGESTS TEMPERATURES WILL NOT PEAK MUCH
OUT OF THE MID 60S. NOT READY TO MAKE ANY CHANGES AT THIS
POINT...BUT IT IS A CONCERNING TREND. ALSO...NEW GUIDANCE SUGGESTS
SEA FOG OFFSHORE MAY MOVE INLAND LATE THIS AFTERNOON AND SPREAD
INLAND THIS EVENING. THIS IS NOT SPECIFICALLY ADDRESSED IN THE
FORECAST...BUT AGAIN...THIS TREND WILL HAVE TO BE MONITORED.
TODAY...THE WESTERN PERIPHERY OF ATLANTIC HIGH PRESSURE WILL
EXTEND ACROSS THE SOUTHEAST U.S. TODAY AS A POTENT STORM SYSTEM
MATURES ACROSS THE CENTRAL PLAINS. BROAD WARM AIR ADVECTION
AHEAD OF THIS SYSTEM WILL PUSH H8 TEMPERATURES TO +12-13C WHICH
COUPLED WITH SOME INSOLATION WILL ALLOW HIGHS TO SOAR IN THE MID-
UPPER 70S AWAY FROM THE COAST. AN ONSHORE FLOW OVER THE COLDER
SHELF WATERS WILL TEMPER THERMAL RISES A BIT ROUGHLY EAST OF
HIGHWAY 17 IN SOUTH CAROLINA AND I-95 IN SOUTHEAST GEORGIA WITH
THE BEACHES LIKELY NOT WARMING OUT OF THE UPPER 50S/LOWER 60S.
LOOKS LIKE THE HIGHS AT BOTH THE SAVANNAH AND CHARLESTON AIRPORTS
WILL REMAIN BELOW RECORD TERRITORY--84 SET IN 1957 AT SAVANNAH AND
79 SET IN 2002 AND 1947 AT CHARLESTON.
THE DAY WILL START OUT CLOUDY DUE TO WIDESPREAD FOG AND STRATUS
WHICH WILL DISSIPATE BY MID-MORNING YIELDING AT LEAST PARTLY
CLOUDY SKIES. CLOUDS WILL THEN BEGIN TO INCREASE LATER THIS
AFTERNOON AS ISENTROPIC ASSENT/WARM AIR ADVECTION STRENGTHENS IN
RESPONSE TO AN INTENSIFYING LOW-LEVEL JET. THE CORE OF THE
STRONGEST LIFT LOOKS TO REMAIN DISPLACED WELL TO THE WEST...SO IT
APPEARS THE NAM/S DEPICTION OF ISOLATED TO SCATTERED SHOWERS
FORMING INLAND IS LIKELY TOO AGGRESSIVE PER THE LATEST RAP/H3R
RUNS. WILL KEEP THE FORECAST RAIN FREE FOR NOW WITH GRIDDED POPS
GENERALLY LESS THAN 10 PERCENT.
THERE IS A POSSIBILITY THAT SOME SEA FOG WILL FORM OVER THE COOL
NEARSHORE WATERS THIS AFTERNOON AS DEWPOINTS RISE INTO THE LOWER-
MID 60S. AS SOUTHERLY WINDS INCREASE...THERE IS A POSSIBILITY THAT
SOME OF THIS COULD PUSH INLAND AND AFFECT SOME BEACH COMMUNITIES.
THIS IS CERTAINLY SOMETHING THAT WILL HAVE TO BE WATCHED VERY
CAREFULLY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
TONIGHT...IT WILL BE A RELATIVELY WARM NIGHT FOR LATE JANUARY
WITH THE REGION PLACED SOLIDLY WITHIN THE WARM SECTOR OF THE
APPROACHING FRONTAL SYSTEM. A STRENGTHENING LOW-LEVEL JET WILL
KEEP THE ATMOSPHERE WELL MIXED WITH THE BOUNDARY LAYER REMAINING
DECOUPLED. LOWS WILL ONLY BOTTOM OUT IN THE LOWER 60S FOR MOST
LOCALES. IT APPEARS THE BEST RAIN CHANCES WILL REMAIN WELL TO THE
WEST CLOSER TO THE FRONT ITSELF...BUT WOULD NOT BE SURPRISED TO SEE
SOME VERY LIGHT SHOWER ACTIVITY DEVELOP OVER THE FAR NORTHERN
ZONES EARLY WEDNESDAY IN THE STRONG WARM AIR ADVECTION REGIME.
WILL KEEP THE FORECAST DRY FOR NOW...ALTHOUGH THE INTRODUCTION OF
AT LEAST ISOLATED SHOWERS MAY BE NEEDED IN LATER FORECAST CYCLES.
WEDNESDAY...THE AXIS OF A ROBUST UPPER TROUGH WILL SWEEP FROM THE
GREAT PLAINS INTO THE OHIO/TENNESSEE VALLEY THROUGH THE
DAY...PROVIDING THE ENERGY TO PUSH A STRONG COLD FRONT INTO THE
FORECAST AREA BY THE LATE AFTERNOON/EARLY EVENING HOURS.
IMPRESSIVE DYNAMICS WILL BE ENHANCING A LINE OF CONVECTION MOVING
EASTWARD WITH THE COLD FRONT...WHILE LATEST NUMERICAL MODEL SOLUTIONS
DELAY THE INTRUSION OF THESE SHOWERS/THUNDERSTORMS UNTIL AT LEAST
21Z TO 00Z. WARM ADVECTION COULD STILL INITIATE SOME ISOLATED TO
SCATTERED SHOWER ACTIVITY AHEAD OF THE FRONT...AND HAVE THUS
INTRODUCED 20 TO 30 PERCENT RAIN CHANCES AS EARLY AS MID MORNING.
RAIN COVERAGE AND INTENSITY WILL THEN GRADUALLY INCREASE FROM
WEST TO EAST AS THE FRONT APPROACHES THE REGION...PEAKING IN THE
EVENING/NIGHTTIME PERIOD. THE MAIN QUESTION THEN BECOMES THE
POTENTIAL FOR SEVERE WEATHER LATE WEDNESDAY.
STORM PREDICTION CENTER HAS MAINTAINED A SLIGHT RISK FOR SEVERE
WEATHER ACROSS THE FORECAST AREA ON WEDNESDAY. DYNAMICS ASSOCIATED
WITH THE APPROACHING FRONTAL SYSTEM ARE CONCERNING...AS A 50 TO
60 KT LOW LEVEL JET MOVES DIRECTLY OVER THE AREA BY THE EVENING
HOURS. THE AXIS OF THE UPPER JET WILL BE DELAYED TO THE
WEST...HOWEVER THE FORECAST AREA WILL STILL BECOME LOCATED UNDER
110 TO 120 KT FLOW ALOFT ALONG THE EASTERN PERIPHERY OF THE JET.
SHEAR PROFILES WILL THUS BE QUITE STRONG...AND WHEN COMBINED WITH
A TIGHTENED PRESSURE GRADIENT AHEAD OF THE COLD FRONT...PREVAILING
WINDS ACROSS THE FORECAST AREA WILL BE GUSTY EVEN BEFORE STRONGEST
PRECIPITATION ARRIVES. AS TEMPERATURES WARM WELL ABOVE NORMAL INTO
THE UPPER 70S TO NEAR 80 DEGREES...MIXING DURING THE PEAK HEATING
HOURS COULD TAP INTO THE IMPRESSIVE BOUNDARY LAYER WINDS AND
SUPPORT WIND ADVISORY CONDITIONS. HOWEVER...AS THE CONVECTIVE
PRECIPITATION ASSOCIATED WITH THE COLD FRONT APPROACHES...INSTABILITY
AND LAPSE RATES STILL APPEAR MARGINAL AT BEST. THIS LENDS SOME
UNCERTAINTY TO THE POTENTIAL FOR STORMS TO BECOME SEVERE AND
PRODUCE DAMAGING WINDS GUSTS. DUE TO THE STRONG DYNAMICS FOR
FORCING...WILL MAINTAIN MENTION OF A SLIGHT CHANCE FOR
THUNDER...YET REMAIN SOMEWHAT CONSERVATIVE DUE TO THE INHERENT
ISSUES OF HIGH SHEAR/LOW INSTABILITY ENVIRONMENTS. WILL MAINTAIN
MENTION OF SEVERE POTENTIAL IN THE HAZARDOUS WEATHER OUTLOOK TO
ADDRESS THE POSSIBILITY OF AT LEAST ISOLATED SEVERE THUNDERSTORM
DEVELOPMENT.
WEDNESDAY NIGHT AND THURSDAY...THE UPPER TROUGH WILL LIFT AND
FLATTEN BY WEDNESDAY NIGHT...WITH THE COLD FRONT RAPIDLY MOVING
OFFSHORE BY DAYBREAK THURSDAY. PRECIPITATION POTENTIAL PEAKING
BEFORE MIDNIGHT WILL QUICKLY DECREASE FROM WEST TO EAST DURING THE
PRE DAWN HOURS...WITH RAIN CHANCES BELOW 15 PERCENT BY SUNRISE.
DRY HIGH PRESSURE WILL BUILD BEHIND THE DEPARTING SYSTEM...AND
STRONG COLD ADVECTION WILL SUPPORT HIGH TEMPERATURES THURSDAY
AFTERNOON 15 TO 20 DEGREES COOLER THAN THE PREVIOUS DAY. HIGHS
WILL BE SUPPRESSED AROUND 60 DEGREES DESPITE SCATTERING SKY COVER
AND BETTER INSOLATION. CONTINUING COLD ADVECTION AND TIGHTENED
PRESSURE GRADIENTS WILL SUPPORT ANOTHER BREEZY
AFTERNOON...ESPECIALLY AS BETTER MIXING UNDER CLEARING SKIES TAPS
INTO BOUNDARY LAYER FLOW. LOW TEMPERATURES THURSDAY NIGHT WILL
ALSO REFLECT THE SIGNIFICANT CHANCE IN AIR MASS...WITH
TEMPERATURES FALLING INTO THE LOW 30S INLAND TO THE MID/UPPER 30S
CLOSER TO THE COAST.
FRIDAY...HIGH PRESSURE WILL BE REINFORCED FROM THE NORTH...AND
WITH NEARLY ZONAL FLOW ALOFT...EXPECT ANOTHER DRY AND COOL DAY.
TEMPERATURES WILL RANGE RIGHT AROUND SEASONAL NORMALS FOR EARLY
FEBRUARY...PEAKING AROUND 60 DEGREES UNDER MOSTLY SUNNY SKIES.
&&
.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
AN UPPER LEVEL SHORTWAVE WILL AMPLIFY AS IT SLIPS SOUTHEAST INTO
THE REGION ON SATURDAY...ALLOWING A WEAK WAVE OF LOW PRESSURE AND
COLD FRONT TO MOVE ACROSS THE MID ATLANTIC AND SOUTHEAST STATES.
DEEP MOISTURE AND DYNAMICS WILL BE MUCH MORE LIMITED WITH THIS
SYSTEM...AND HAVE THUS MAINTAINED A DRY FORECAST. HIGH PRESSURE
WILL QUICKLY REBUILD BEHIND THE DEPARTING SHORTWAVE AND
FRONT...STEADILY MOVING INTO THE ATLANTIC EARLY NEXT WEEK. A
STRONGER COLD FRONT COULD APPROACH THE FORECAST AREA BY
TUESDAY...HOWEVER WILL KEEP POPS BELOW 15 PERCENT DUE TO TIMING
AND IMPACT UNCERTAINTIES THIS FAR IN ADVANCE. HIGH TEMPERATURES
WILL GENERALLY REACH THE LOW 60S EACH AFTERNOON...WITH LOWS
MODERATING INTO THE UPPER 30S TO LOWER 40S.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
BIGGEST CONCERN IS TRYING TO TIME WHEN THE FOG WILL LIFT ABOVE
VARIOUS AIRPORT MINIMUMS. LOOKS LIKE LIFR VSBYS WILL LINGER
THROUGH ABOUT 14Z WITH SOME IMPROVEMENT BETWEEN 14-16Z. ITS
UNCLEAR WHETHER IFR OR MVFR CIGS WILL ESTABLISH THEMSELVES AS THE
FOG LAYER LIFTS...BUT WILL HIGHLIGHT SOME CIGS TO COVER. EXPECT
VFR TO RETURN BY 16-17Z AT BOTH TERMINALS. BIG QUESTION LATE THIS
AFTERNOON AND OVERNIGHT IS WHETHER SEA FOG WILL MOVE INLAND AND
IMPACT THE TERMINALS BY EARLY EVENING. GUIDANCE IS ALL OVER THE
PLACE ON THIS POTENTIAL SO LIMITED CONDITIONS TO MVFR FOR NOW.
COULD SEE MARGINAL LOW-LEVEL WIND SHEAR EARLY WEDNESDAY...BUT WILL
NOT INTRODUCE JUST YET AS IT LOOK MARGINAL.
EXTENDED AVIATION OUTLOOK...WINDY CONDITIONS EXPECTED ON
WEDNESDAY...WITH LOW-LEVEL WIND SHEAR POSSIBLE WEDNESDAY MORNING
BEFORE MIXING INCREASES LATE MORNING. TEMPO MVFR OR LOWER CIGS/
VSBYS ARE POSSIBLE WEDNESDAY EVENING/NIGHT WITH SHOWERS AND/OR
THUNDERSTORMS ALONG A COLD FRONT. EXPECT PREVAILING VFR CONDITIONS
TO RETURN BY THURSDAY INTO THE LATE WEEK PERIOD.
&&
.MARINE...
TODAY...MARINE DENSE FOG ADVISORY FOR THE CHARLESTON HARBOR UNTIL
10 AM AND ALL NEARSHORE LEGS UNTIL 1 PM. WEBCAMS SUGGEST VERY
DENSE FOG HAS DEVELOPED OFFSHORE. THE FOG WILL LIKELY LINGER WELL
INTO THE DAY AS THE FOG WILL REMAIN TRAPPED WITHIN THE STRONG
MARINE LAYER.
LIGHT WINDS WILL BECOME SOUTHERLY AND INCREASE TO 5-10 KT TODAY
AHEAD OF AN APPROACHING COLD FRONT. INCREASING DEWPOINTS OVER THE
CHILLY SHELF WATERS COULD SUPPORT AT LEAST PATCHY SEA FOG OVER THE
NEARSHORE WATERS TODAY. IT REMAINS TO BE SEEN HOW WIDESPREAD ANY
SEA FOG COULD BECOME...BUT A MARINE DENSE FOG ADVISORIES MAY BE
NEEDED AT SOME POINT. SEAS WILL RANGE FROM 2-4 FT...HIGHEST
OFFSHORE WATERS.
TONIGHT...WINDS WILL BEGIN TO INCREASE AS LOW-LEVEL JETTING
INTENSIFIES AHEAD OF THE APPROACHING COLD FRONT. WINDS LOOK TO MAX
OUT AT 15-20 KT ALL WATERS AND LOCAL SWAN OUTPUT SUGGESTS SEAS
WILL REMAIN BELOW 6 FT...SO WILL NOT HOIST A SMALL CRAFT ADVISORY
FOR ANY MARINE LEGS FOR THE TONIGHT PERIOD. ANY SEA FOG COULD
LINGER IN THE NEARSHORE WATERS FOR MUCH OF THE NIGHT.
WEDNESDAY THROUGH SATURDAY...MARINE CONDITIONS WILL RAPIDLY
DETERIORATE ON WEDNESDAY...AS THE PRESSURE GRADIENT TIGHTENS
SIGNIFICANTLY AHEAD OF A COLD FRONT AND AN IMPRESSIVE 50 TO 60 KT
LOW LEVEL JET MOVES OVER THE AREA. DUE TO DECENT CONFIDENCE IN
SECOND AND THIRD PERIOD WIND POTENTIAL...HAVE ISSUED SMALL CRAFT
ADVISORIES FOR ALL NEARSHORE WATERS AND THE CHARLESTON HARBOR
BEGINNING 15Z WEDNESDAY. HAVE ALSO RAISED A GALE WATCH FOR THE
OFFSHORE GEORGIA WATERS AT 15Z...WHEN FREQUENT GUSTS ABOVE 34 KT
ARE MOST LIKELY TO INITIATE. GALE CONDITIONS COULD ALSO OCCUR
ACROSS THE NEARSHORE WATERS...ESPECIALLY THE MARINE ZONES ADJACENT
TO CHARLESTON COUNTY...HOWEVER TIMING SUGGESTS THESE CONDITIONS
ARE MORE LIKELY TO BE DELAYED TOWARD WEDNESDAY EVENING OR NIGHT.
WILL THUS HOLD OFF ON A GALE WARNING FOR THE NEARSHORE ZONES AT
THIS TIME. SEAS WILL BUILD AHEAD OF THE FRONT...PEAKING BETWEEN
5-10 FT BEYOND 10 NM FROM THE COAST. ALTHOUGH THE FRONT WILL
RAPIDLY SHIFT OUT OF THE AREA BY THURSDAY MORNING...OFFSHORE WINDS
WILL STILL BE QUITE STRONG IN A LOW LEVEL COLD ADVECTION
PATTERN...AND SMALL CRAFT ADVISORY CONDITIONS COULD LINGER THROUGH
AT LEAST THURSDAY AFTERNOON. WINDS AND SEAS WILL THEN STEADILY
DIMINISH THURSDAY NIGHT...REMAINING BELOW ADVISORY CRITERIA FOR THE
REMAINDER OF THE FORECAST PERIOD WITH HIGH PRESSURE GENERALLY IN
CONTROL.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...DENSE FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR GAZ087-088-
099>101-114>119-137>141.
SC...DENSE FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR SCZ040-
042>045-047>052.
MARINE...DENSE FOG ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR AMZ350-
352-354.
SMALL CRAFT ADVISORY FROM 10 AM WEDNESDAY TO 7 PM EST THURSDAY
FOR AMZ330-350-352-354.
GALE WATCH FROM WEDNESDAY MORNING THROUGH THURSDAY MORNING FOR
AMZ374.
DENSE FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR AMZ330.
&&
$$
ST/79
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
622 AM EST TUE JAN 29 2013
.SYNOPSIS...
ATLANTIC HIGH PRESSURE WILL PREVAIL TONIGHT INTO WEDNESDAY. A
STRONG COLD FRONT WILL APPROACH FROM THE WEST WEDNESDAY...BRINGING
WINDY CONDITIONS AND THE THREAT OF THUNDERSTORMS. AFTER THE COLD
FRONT PUSHES OFFSHORE WEDNESDAY NIGHT...HIGH PRESSURE WILL SUPPORT
COOLER AND DRIER CONDITIONS INTO NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
DENSE FOG ADVISORY ALL ZONES UNTIL 10 AM. HIGH RESOLUTION DATA
SUGGESTS FOG MAY LINGER WELL INTO THE MORNING OVER MUCH OF
INTERIOR SOUTHEAST SOUTH CAROLINA WHICH MAY HAVE AN IMPACT ON HIGH
TEMPERATURES. LATEST RAP SUGGESTS TEMPERATURES WILL NOT PEAK MUCH
OUT OF THE MID 60S. NOT READY TO MAKE ANY CHANGES AT THIS
POINT...BUT IT IS A CONCERNING TREND. ALSO...NEW GUIDANCE SUGGESTS
SEA FOG OFFSHORE MAY MOVE INLAND LATE THIS AFTERNOON AND SPREAD
INLAND THIS EVENING. THIS IS NOT SPECIFICALLY ADDRESSED IN THE
FORECAST...BUT AGAIN...THIS TREND WILL HAVE TO BE MONITORED.
TODAY...THE WESTERN PERIPHERY OF ATLANTIC HIGH PRESSURE WILL
EXTEND ACROSS THE SOUTHEAST U.S. TODAY AS A POTENT STORM SYSTEM
MATURES ACROSS THE CENTRAL PLAINS. BROAD WARM AIR ADVECTION
AHEAD OF THIS SYSTEM WILL PUSH H8 TEMPERATURES TO +12-13C WHICH
COUPLED WITH SOME INSOLATION WILL ALLOW HIGHS TO SOAR IN THE MID-
UPPER 70S AWAY FROM THE COAST. AN ONSHORE FLOW OVER THE COLDER
SHELF WATERS WILL TEMPER THERMAL RISES A BIT ROUGHLY EAST OF
HIGHWAY 17 IN SOUTH CAROLINA AND I-95 IN SOUTHEAST GEORGIA WITH
THE BEACHES LIKELY NOT WARMING OUT OF THE UPPER 50S/LOWER 60S.
LOOKS LIKE THE HIGHS AT BOTH THE SAVANNAH AND CHARLESTON AIRPORTS
WILL REMAIN BELOW RECORD TERRITORY--84 SET IN 1957 AT SAVANNAH AND
79 SET IN 2002 AND 1947 AT CHARLESTON.
THE DAY WILL START OUT CLOUDY DUE TO WIDESPREAD FOG AND STRATUS
WHICH WILL DISSIPATE BY MID-MORNING YIELDING AT LEAST PARTLY
CLOUDY SKIES. CLOUDS WILL THEN BEGIN TO INCREASE LATER THIS
AFTERNOON AS ISENTROPIC ASSENT/WARM AIR ADVECTION STRENGTHENS IN
RESPONSE TO AN INTENSIFYING LOW-LEVEL JET. THE CORE OF THE
STRONGEST LIFT LOOKS TO REMAIN DISPLACED WELL TO THE WEST...SO IT
APPEARS THE NAM/S DEPICTION OF ISOLATED TO SCATTERED SHOWERS
FORMING INLAND IS LIKELY TOO AGGRESSIVE PER THE LATEST RAP/H3R
RUNS. WILL KEEP THE FORECAST RAIN FREE FOR NOW WITH GRIDDED POPS
GENERALLY LESS THAN 10 PERCENT.
THERE IS A POSSIBILITY THAT SOME SEA FOG WILL FORM OVER THE COOL
NEARSHORE WATERS THIS AFTERNOON AS DEWPOINTS RISE INTO THE LOWER-
MID 60S. AS SOUTHERLY WINDS INCREASE...THERE IS A POSSIBILITY THAT
SOME OF THIS COULD PUSH INLAND AND AFFECT SOME BEACH COMMUNITIES.
THIS IS CERTAINLY SOMETHING THAT WILL HAVE TO BE WATCHED VERY
CAREFULLY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
TONIGHT...IT WILL BE A RELATIVELY WARM NIGHT FOR LATE JANUARY
WITH THE REGION PLACED SOLIDLY WITHIN THE WARM SECTOR OF THE
APPROACHING FRONTAL SYSTEM. A STRENGTHENING LOW-LEVEL JET WILL
KEEP THE ATMOSPHERE WELL MIXED WITH THE BOUNDARY LAYER REMAINING
DECOUPLED. LOWS WILL ONLY BOTTOM OUT IN THE LOWER 60S FOR MOST
LOCALES. IT APPEARS THE BEST RAIN CHANCES WILL REMAIN WELL TO THE
WEST CLOSER TO THE FRONT ITSELF...BUT WOULD NOT BE SURPRISED TO SEE
SOME VERY LIGHT SHOWER ACTIVITY DEVELOP OVER THE FAR NORTHERN
ZONES EARLY WEDNESDAY IN THE STRONG WARM AIR ADVECTION REGIME.
WILL KEEP THE FORECAST DRY FOR NOW...ALTHOUGH THE INTRODUCTION OF
AT LEAST ISOLATED SHOWERS MAY BE NEEDED IN LATER FORECAST CYCLES.
WEDNESDAY...THE AXIS OF A ROBUST UPPER TROUGH WILL SWEEP FROM THE
GREAT PLAINS INTO THE OHIO/TENNESSEE VALLEY THROUGH THE
DAY...PROVIDING THE ENERGY TO PUSH A STRONG COLD FRONT INTO THE
FORECAST AREA BY THE LATE AFTERNOON/EARLY EVENING HOURS.
IMPRESSIVE DYNAMICS WILL BE ENHANCING A LINE OF CONVECTION MOVING
EASTWARD WITH THE COLD FRONT...WHILE LATEST NUMERICAL MODEL SOLUTIONS
DELAY THE INTRUSION OF THESE SHOWERS/THUNDERSTORMS UNTIL AT LEAST
21Z TO 00Z. WARM ADVECTION COULD STILL INITIATE SOME ISOLATED TO
SCATTERED SHOWER ACTIVITY AHEAD OF THE FRONT...AND HAVE THUS
INTRODUCED 20 TO 30 PERCENT RAIN CHANCES AS EARLY AS MID MORNING.
RAIN COVERAGE AND INTENSITY WILL THEN GRADUALLY INCREASE FROM
WEST TO EAST AS THE FRONT APPROACHES THE REGION...PEAKING IN THE
EVENING/NIGHTTIME PERIOD. THE MAIN QUESTION THEN BECOMES THE
POTENTIAL FOR SEVERE WEATHER LATE WEDNESDAY.
STORM PREDICTION CENTER HAS MAINTAINED A SLIGHT RISK FOR SEVERE
WEATHER ACROSS THE FORECAST AREA ON WEDNESDAY. DYNAMICS ASSOCIATED
WITH THE APPROACHING FRONTAL SYSTEM ARE CONCERNING...AS A 50 TO
60 KT LOW LEVEL JET MOVES DIRECTLY OVER THE AREA BY THE EVENING
HOURS. THE AXIS OF THE UPPER JET WILL BE DELAYED TO THE
WEST...HOWEVER THE FORECAST AREA WILL STILL BECOME LOCATED UNDER
110 TO 120 KT FLOW ALOFT ALONG THE EASTERN PERIPHERY OF THE JET.
SHEAR PROFILES WILL THUS BE QUITE STRONG...AND WHEN COMBINED WITH
A TIGHTENED PRESSURE GRADIENT AHEAD OF THE COLD FRONT...PREVAILING
WINDS ACROSS THE FORECAST AREA WILL BE GUSTY EVEN BEFORE STRONGEST
PRECIPITATION ARRIVES. AS TEMPERATURES WARM WELL ABOVE NORMAL INTO
THE UPPER 70S TO NEAR 80 DEGREES...MIXING DURING THE PEAK HEATING
HOURS COULD TAP INTO THE IMPRESSIVE BOUNDARY LAYER WINDS AND
SUPPORT WIND ADVISORY CONDITIONS. HOWEVER...AS THE CONVECTIVE
PRECIPITATION ASSOCIATED WITH THE COLD FRONT APPROACHES...INSTABILITY
AND LAPSE RATES STILL APPEAR MARGINAL AT BEST. THIS LENDS SOME
UNCERTAINTY TO THE POTENTIAL FOR STORMS TO BECOME SEVERE AND
PRODUCE DAMAGING WINDS GUSTS. DUE TO THE STRONG DYNAMICS FOR
FORCING...WILL MAINTAIN MENTION OF A SLIGHT CHANCE FOR
THUNDER...YET REMAIN SOMEWHAT CONSERVATIVE DUE TO THE INHERENT
ISSUES OF HIGH SHEAR/LOW INSTABILITY ENVIRONMENTS. WILL MAINTAIN
MENTION OF SEVERE POTENTIAL IN THE HAZARDOUS WEATHER OUTLOOK TO
ADDRESS THE POSSIBILITY OF AT LEAST ISOLATED SEVERE THUNDERSTORM
DEVELOPMENT.
WEDNESDAY NIGHT AND THURSDAY...THE UPPER TROUGH WILL LIFT AND
FLATTEN BY WEDNESDAY NIGHT...WITH THE COLD FRONT RAPIDLY MOVING
OFFSHORE BY DAYBREAK THURSDAY. PRECIPITATION POTENTIAL PEAKING
BEFORE MIDNIGHT WILL QUICKLY DECREASE FROM WEST TO EAST DURING THE
PRE DAWN HOURS...WITH RAIN CHANCES BELOW 15 PERCENT BY SUNRISE.
DRY HIGH PRESSURE WILL BUILD BEHIND THE DEPARTING SYSTEM...AND
STRONG COLD ADVECTION WILL SUPPORT HIGH TEMPERATURES THURSDAY
AFTERNOON 15 TO 20 DEGREES COOLER THAN THE PREVIOUS DAY. HIGHS
WILL BE SUPPRESSED AROUND 60 DEGREES DESPITE SCATTERING SKY COVER
AND BETTER INSOLATION. CONTINUING COLD ADVECTION AND TIGHTENED
PRESSURE GRADIENTS WILL SUPPORT ANOTHER BREEZY
AFTERNOON...ESPECIALLY AS BETTER MIXING UNDER CLEARING SKIES TAPS
INTO BOUNDARY LAYER FLOW. LOW TEMPERATURES THURSDAY NIGHT WILL
ALSO REFLECT THE SIGNIFICANT CHANCE IN AIR MASS...WITH
TEMPERATURES FALLING INTO THE LOW 30S INLAND TO THE MID/UPPER 30S
CLOSER TO THE COAST.
FRIDAY...HIGH PRESSURE WILL BE REINFORCED FROM THE NORTH...AND
WITH NEARLY ZONAL FLOW ALOFT...EXPECT ANOTHER DRY AND COOL DAY.
TEMPERATURES WILL RANGE RIGHT AROUND SEASONAL NORMALS FOR EARLY
FEBRUARY...PEAKING AROUND 60 DEGREES UNDER MOSTLY SUNNY SKIES.
&&
.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
AN UPPER LEVEL SHORTWAVE WILL AMPLIFY AS IT SLIPS SOUTHEAST INTO
THE REGION ON SATURDAY...ALLOWING A WEAK WAVE OF LOW PRESSURE AND
COLD FRONT TO MOVE ACROSS THE MID ATLANTIC AND SOUTHEAST STATES.
DEEP MOISTURE AND DYNAMICS WILL BE MUCH MORE LIMITED WITH THIS
SYSTEM...AND HAVE THUS MAINTAINED A DRY FORECAST. HIGH PRESSURE
WILL QUICKLY REBUILD BEHIND THE DEPARTING SHORTWAVE AND
FRONT...STEADILY MOVING INTO THE ATLANTIC EARLY NEXT WEEK. A
STRONGER COLD FRONT COULD APPROACH THE FORECAST AREA BY
TUESDAY...HOWEVER WILL KEEP POPS BELOW 15 PERCENT DUE TO TIMING
AND IMPACT UNCERTAINTIES THIS FAR IN ADVANCE. HIGH TEMPERATURES
WILL GENERALLY REACH THE LOW 60S EACH AFTERNOON...WITH LOWS
MODERATING INTO THE UPPER 30S TO LOWER 40S.
&&
.AVIATION /11Z TUESDAY THROUGH SATURDAY/...
FOG IS ALREADY BEGINNING TO FORM AT BOTH TERMINALS EARLY THIS
MORNING. THE FOG IS PRETTY SHALLOW SO FAR WHICH WILL LIKELY RESULT
IN VSBYS BOUNCING FOR A FEW MORE HOURS BEFORE SETTLING DOWN AFTER
09Z ONCE THE FOG LAYERS THICKEN. ANTICIPATE LIFR CONDITIONS TO
IMPACT THE TERMINALS WITH BOTH CIGS AND VSBYS REACHING AIRPORT
MINIMUMS. THERE IS SOME HINT THAT A MID-LEVEL CLOUD DECK AROUND
5000 FT COULD DEVELOP JUST AS THE FOG POTENTIAL PEAKS. IT IS
UNCLEAR WHETHER THIS LAYER WILL FORM...BUT IF IT DOES CONDITIONS
COULD STAY ABOVE AIRFIELD AND POSSIBLY ALTERNATE MINIMUMS. FOR
NOW...WILL SHOW PREVAILING LIFR CONDITIONS AT BOTH TERMINALS BY
09Z AND MAINTAIN THIS UNTIL 14-15Z AFTER WHICH CONDITIONS WILL
IMPROVE TO VFR AS THE FOG LAYER DISSIPATES.
EXTENDED AVIATION OUTLOOK...WINDY CONDITIONS EXPECTED ON
WEDNESDAY...WITH LOW-LEVEL WIND SHEAR POSSIBLE WEDNESDAY MORNING
BEFORE MIXING INCREASES LATE MORNING. TEMPO MVFR OR LOWER CIGS/
VSBYS ARE POSSIBLE WEDNESDAY EVENING/NIGHT WITH SHOWERS AND/OR
THUNDERSTORMS ALONG A COLD FRONT. EXPECT PREVAILING VFR CONDITIONS
TO RETURN BY THURSDAY INTO THE LATE WEEK PERIOD.
&&
.MARINE...
TODAY...MARINE DENSE FOG ADVISORY FOR THE CHARLESTON HARBOR UNTIL
10 AM AND ALL NEARSHORE LEGS UNTIL 1 PM. WEBCAMS SUGGEST VERY
DENSE FOG HAS DEVELOPED OFFSHORE. THE FOG WILL LIKELY LINGER WELL
INTO THE DAY AS THE FOG WILL REMAIN TRAPPED WITHIN THE STRONG
MARINE LAYER.
LIGHT WINDS WILL BECOME SOUTHERLY AND INCREASE TO 5-10 KT TODAY
AHEAD OF AN APPROACHING COLD FRONT. INCREASING DEWPOINTS OVER THE
CHILLY SHELF WATERS COULD SUPPORT AT LEAST PATCHY SEA FOG OVER THE
NEARSHORE WATERS TODAY. IT REMAINS TO BE SEEN HOW WIDESPREAD ANY
SEA FOG COULD BECOME...BUT A MARINE DENSE FOG ADVISORIES MAY BE
NEEDED AT SOME POINT. SEAS WILL RANGE FROM 2-4 FT...HIGHEST
OFFSHORE WATERS.
TONIGHT...WINDS WILL BEGIN TO INCREASE AS LOW-LEVEL JETTING
INTENSIFIES AHEAD OF THE APPROACHING COLD FRONT. WINDS LOOK TO MAX
OUT AT 15-20 KT ALL WATERS AND LOCAL SWAN OUTPUT SUGGESTS SEAS
WILL REMAIN BELOW 6 FT...SO WILL NOT HOIST A SMALL CRAFT ADVISORY
FOR ANY MARINE LEGS FOR THE TONIGHT PERIOD. ANY SEA FOG COULD
LINGER IN THE NEARSHORE WATERS FOR MUCH OF THE NIGHT.
WEDNESDAY THROUGH SATURDAY...MARINE CONDITIONS WILL RAPIDLY
DETERIORATE ON WEDNESDAY...AS THE PRESSURE GRADIENT TIGHTENS
SIGNIFICANTLY AHEAD OF A COLD FRONT AND AN IMPRESSIVE 50 TO 60 KT
LOW LEVEL JET MOVES OVER THE AREA. DUE TO DECENT CONFIDENCE IN
SECOND AND THIRD PERIOD WIND POTENTIAL...HAVE ISSUED SMALL CRAFT
ADVISORIES FOR ALL NEARSHORE WATERS AND THE CHARLESTON HARBOR
BEGINNING 15Z WEDNESDAY. HAVE ALSO RAISED A GALE WATCH FOR THE
OFFSHORE GEORGIA WATERS AT 15Z...WHEN FREQUENT GUSTS ABOVE 34 KT
ARE MOST LIKELY TO INITIATE. GALE CONDITIONS COULD ALSO OCCUR
ACROSS THE NEARSHORE WATERS...ESPECIALLY THE MARINE ZONES ADJACENT
TO CHARLESTON COUNTY...HOWEVER TIMING SUGGESTS THESE CONDITIONS
ARE MORE LIKELY TO BE DELAYED TOWARD WEDNESDAY EVENING OR NIGHT.
WILL THUS HOLD OFF ON A GALE WARNING FOR THE NEARSHORE ZONES AT
THIS TIME. SEAS WILL BUILD AHEAD OF THE FRONT...PEAKING BETWEEN
5-10 FT BEYOND 10 NM FROM THE COAST. ALTHOUGH THE FRONT WILL
RAPIDLY SHIFT OUT OF THE AREA BY THURSDAY MORNING...OFFSHORE WINDS
WILL STILL BE QUITE STRONG IN A LOW LEVEL COLD ADVECTION
PATTERN...AND SMALL CRAFT ADVISORY CONDITIONS COULD LINGER THROUGH
AT LEAST THURSDAY AFTERNOON. WINDS AND SEAS WILL THEN STEADILY
DIMINISH THURSDAY NIGHT...REMAINING BELOW ADVISORY CRITERIA FOR THE
REMAINDER OF THE FORECAST PERIOD WITH HIGH PRESSURE GENERALLY IN
CONTROL.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...DENSE FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR GAZ087-088-
099>101-114>119-137>141.
SC...DENSE FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR SCZ040-
042>045-047>052.
MARINE...DENSE FOG ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR AMZ350-
352-354.
SMALL CRAFT ADVISORY FROM 10 AM WEDNESDAY TO 7 PM EST THURSDAY
FOR AMZ330-350-352-354.
GALE WATCH FROM WEDNESDAY MORNING THROUGH THURSDAY MORNING FOR
AMZ374.
DENSE FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR AMZ330.
&&
$$
ST
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
410 PM CST TUE JAN 29 2013
.MESOSCALE DISCUSSION...
240 PM CST
THE THREAT FOR HEAVY RAIN DEVELOPING AND POSSIBLY A COUPLE SEVERE
STORMS CONTINUES.
THE LATEST HAND ANALYSIS PLACES THE COLD FRONT JUST PAST THE
MISSISSIPPI RIVER IN NORTHWEST IL WITH A SUBTLE PRE-FRONTAL
TROUGH FROM JUST EAST OF ROCKFORD SOUTH TOWARD PEORIA. THIS PRE-
FRONTAL TROUGH DOES HAVE AN INSTABILITY PLUME AIDED BY LOW TO MID
60S TEMPERATURES...AND LOW-LEVEL CAPE IS ANALYZED NEAR 100 J/KG
WITH AROUND 300-500 J/KG OF SURFACE-BASED CAPE. THIS INSTABILITY
THOUGH IS NOT LINING UP WITH ANY GREAT STORM ACTIVITY.
SATELLITE AND RADAR TRENDS SHOW THAT A LARGE SWATH OF RAIN HAS
EXPANDED FROM MO NORTHEAST THROUGH WESTERN IL AND SOUTHERN
WI...STABILIZING MUCH OF THAT AREA. AT THE FRONT EDGE OF
THIS...NEAR THE PRE-FRONTAL TROUGH...MORE CONVECTIVE-LIKE SHOWERS
ARE PRESENT. THAT CONVECTION ON THE ILX RADAR HAS STRUGGLED TO
BECOME WELL-DEFINED AND HAS MORE OF A QUASI-LINEAR MUSHY LOOK
RIGHT NOW. LIGHTNING HAS BEEN SOMEWHAT SPORADIC AND REALLY HAS
ONLY BEEN SEEN IN THE CLUSTER THAT IS NEARING CHICAGO...POSSIBLY
ASSOCIATED WITH A WARM AIR ADVECTION FLANK AHEAD OF THE SYSTEM.
OVERALL THE TREND HAS BEEN SLIGHTLY DOWN WITH NO LOCAL STORMS
APPROACHING SEVERE LIMITS...AND A FEW 30-37 KT GUSTS OBSERVED. AT
THIS TIME...IT REMAINS QUITE MARGINAL FOR SEVERE WEATHER AND MAY
CONTINUE TO THROUGH MUCH OF THE AFTERNOON AS NO IMMEDIATE STRONG
IMPULSES UPSTREAM ARE EVIDENT.
TOWARD SUNSET AND INTO THIS EVENING...AREAS ALONG AND EAST OF I-55
WILL REMAIN FAVORED FOR STORM ACTIVITY ON THE NOSE OF AN
INCREASING LOW LEVEL JET AND JUST MORE IMPROVED OVERALL FORCING.
EXPLICIT CONVECTIVE MODELS AGREE THIS AREA WILL BE UNDER SOME
STRONGER ACTIVITY THIS EVENING...BUT WHETHER THAT IS TO THE
LIMITS TO FLIRT WITH SEVERE IS LOW CONFIDENCE. THE FORECAST DCAPE
DOES INCREASE TO AROUND 400-500 J/KG ON THE NAM AND THE LOW-LEVEL
SHEAR/HELICITY REMAINS HIGH IN THE STRONG ATMOSPHERIC WINDS. THIS
MAY END UP BEING OUR BEST...ALBEIT NARROW WINDOW FOR SEVERE
WEATHER.
HEAVY RAIN REMAINS THE PRIMARY POTENTIAL HAZARD. WHILE IT IS A
QUASI- LINEAR MUSHY LOOK RIGHT NOW...RAINFALL RATES ARE LIKELY
VERY EFFICIENT IN ANY ACTIVITY AND WILL CONTINUE AS SUCH LATE THIS
AFTERNOON INTO TONIGHT. A PERSISTENT FOCUS IS SEEN IN THE RAP AND
NAM FORECASTS AS DEEP LAYER MOISTURE CONVERGENCE FURTHER INCREASES
TONIGHT AS THE UPPER TROUGH INCHES EASTWARD. WIDESPREAD RAINFALL
AMOUNTS OF ONE TO TWO AND A HALF INCHES LOOK LIKELY...WITH
POTENTIALLY THE HIGHER END AMOUNTS BEING WIDESPREAD. WITH MUCH OF
THIS GOING TOWARD RUNOFF...AT LEAST LOCALIZED PONDING TO POSSIBLE
FLOODING WILL BE LIKELY.
MTF
&&
.DISCUSSION...
318 PM CST
SHORT TERM...REST OF TODAY THROUGH WEDNESDAY NIGHT...
FOR HEADLINES...KEPT FLOOD WATCH AS IS AND NO WINTER HEADLINES ARE
EXPECTED AT THIS TIME.
A DEEP TROUGH LIES ACROSS THE WESTERN US WITH ITS AXIS OVER THE
GREAT PLAINS...WHILE A SURFACE LOW IS OVER ONTARIO. THE SURFACE
LOWS COLD FRONT EXTENDS FROM THE LOW THROUGH CENTRAL WI TO ALONG THE
MISSISSIPPI RIVER...AND IT IS SLOWLY MAKING ITS WAY INTO WESTERN
IL. THE TEMPERATURE GRADIENT ACROSS THE FRONT IS RATHER IMPRESSIVE
WITH 60 DEGREES IN PERU IL AND 38 DEGREES IN OTTUMWA IA...WITH JUST
176 MILES BETWEEN THE TWO CITIES. SHOWERS AND THUNDERSTORMS HAVE
SPREAD INTO NORTHERN IL AHEAD OF THE COLD FRONT AND WILL CONTINUE TO
SPREAD ACROSS THE CWA THIS AFTERNOON/EARLY EVENING. INDIVIDUAL CELLS
HAVE BEEN CLOCKED AT 50-60 KT MOVING FROM THE SOUTHWEST TO THE
NORTHEAST. SEVERE STORMS ARE STILL POSSIBLE THIS AFTERNOON...FOR
MORE INFORMATION ON THE SEVERE WEATHER OUTLOOK AND RELATED
PARAMETERS PLEASE SEE THE MESOSCALE DISCUSSION ABOVE.
PWAT VALUES WILL BE IN EXCESS OF 1-1.5 INCHES THIS AFTERNOON/EVENING
WITH DEWPOINTS CURRENTLY IN THE UPPER 50S TO LOW 60S FALLING
OVERNIGHT. FLOW THROUGHOUT THE ATMOSPHERIC COLUMN IS ROUGHLY
PARALLEL TO THE FRONT WHICH WILL INHIBIT THE FRONT FROM RAPIDLY
PROGRESSING THROUGH THE CWA. TRAINING WILL ALSO BECOME AN ISSUE
ALONG THE FRONT ALLOWING FOR IMPRESSIVE RAIN TOTALS. THE UPPER
LEVEL JET STRETCHES FROM TEXAS THROUGH MINNESOTA BEFORE CURVING
TOWARD QUEBEC. THE RIGHT JET ENTRANCE REGION LIES OVER SOUTHWEST
WI/NORTHWEST IL ALMOST COLLOCATED WITH THE FRONT WHICH WILL CONTINUE
TO SUPPORT THUNDERSTORM AND SHOWER FORMATION. BASED ON WHAT HAS
PASSED OVER THE OFFICE THIS AFTERNOON...SOME OF THESE SHOWERS/STORMS
WILL PRODUCE BRIEF INTENSE DOWNPOURS. THE JET AND FRONT CONTINUE
ACROSS THE CWA TONIGHT WITH THE SOUTHERN JET STREAKS LEFT EXIT
REGION POSSIBLY COUPLING WITH THE FRONT. AS SUCH EXPECTING PERIODS
OF HEAVY RAIN TO CONTINUE OVERNIGHT. WHEN ALL IS SAID AND
DONE...THINKING 1.5-2.5 INCHES OF RAIN ARE POSSIBLE ACROSS THE
AREA. LOCALLY HIGHER AMOUNTS ARE CERTAINLY POSSIBLE.
QUICKLY CHECKING THE OFFICES SOIL TEMPS...2 AND 4 INCHES BELOW THE
SURFACE ARE ABOVE FREEZING AT 35 DEGREES WHILE 8 INCHES IS STILL
FROZEN AT 27 DEGREES. AS SUCH EXPECTING PONDING OF WATER IN THE
TYPICAL LOW LYING SPOTS...SINCE THE SOIL WILL NOT BE ABLE TO TAKE IN
AS MUCH WATER AS USUAL. THEREFORE MADE NO ADJUSTMENTS TO THE FLOOD
WATCH.
TEMPS WILL BEGIN TO FALL OVERNIGHT WITH LOWS IN THE LOW 30S NEAR RFD
TO ARND 50 NEAR RENSSELAER.
WEDNESDAY...
TEMPS WILL CONTINUE TO FALL WEDNESDAY MORNING WITH PRECIP
TRANSITIONING TO SNOW AS A SWATH OF MOISTURE ASSOCIATED WITH THE 700
MB LOW SURGES NORTH. SOUNDINGS INDICATE A BRIEF PERIOD OF SLEET IS
POSSIBLE DURING THE TRANSITION BUT NOT EXPECTING ANY SIGNIFICANT
SLEET ACCUMULATION. EXPECTING AREAS AROUND RFD TO CHANGE OVER TO
SNOW BEFORE 8AM...CHICAGO AROUND 3PM...AND NW INDIANA 4-6PM.
FOR SNOW TOTALS...EXPECTING THE HIGHEST TOTALS IN FAR NW IL IN
WINNEBAGO AND OGLE COUNTIES. THE NAM IS MUCH MORE EXCITED THAN THE
GFS ABOUT THE SNOW POTENTIAL BUT BOTH MODELS SHOW THE SAME SET UP
THAT IS FAVORABLE FOR MESOSCALE SNOW BANDS. 850-700 MB
FRONTOGENESIS MOVES OVER NW IL/E IA EARLY WEDNESDAY MORNING WITH EPV
VALUES BELOW 0 JUST ABOVE IT...INDICATING LOCALIZED INTENSE FORCING
AND SYMMETRIC INSTABILITY. HOWEVER EXPECTING TEMPS TO BE ABOVE
FREEZING AT THIS POINT. THE FRONTOGENESIS AND INSTABILITY SHIFT
EASTWARD THROUGH THE MORNING AND THEN WEAKEN AFTER NOON. THE LEFT
JET EXIT REGION OF THE UPPER LEVEL JET WILL ALSO BE OVER NORTHERN IL
THROUGH WEDNESDAY AFTERNOON SO SYNOPTIC-SCALE LIFT SHOULD NOT BE AN
ISSUE.
WHILE MESOSCALE BANDS OF RAIN OR SNOW ARE VERY LIKELY
TOMORROW...THESE FEATURES ARE HARD TO PINPOINT EVEN THIS FAR OUT.
THEREFORE WENT WITH 3-5 INCHES OF SNOW OVER WINNEBAGO AND OGLE
COUNTIES TOMORROW...BUT THIS NUMBER COULD EASILY BE HIGHER IF A BAND
OF SNOW SETS UP. THE BIG QUESTIONS ARE WILL THE BEST FORCING ALIGN
WITH SNOW OR RAIN...HOW LONG WILL THE FORCING LAST...AND WHERE WILL
THE MESOSCALE BAND SET UP.
AS MENTIONED BEFORE...THE FRONTOGENESIS WEAKENS AND STABILITY
INCREASES IN THE AFTERNOON AS THE SNOW SPREADS ACROSS THE REST OF
THE CWA. SO INTENSE MESOSCALE BANDS ARE NOT AS LIKELY...BUT FORCING
FROM THE UPPER LEVEL JET STILL LOOKS FAVORABLE FOR A LITTLE SNOW. AS
SUCH EXPECTING 1 TO 3 INCHES OF SNOW ACROSS BOONE AND MCHENRY
COUNTIES...AND THEN AN INCH OR LESS EVERYWHERE ELSE. SNOW ENDS FROM
WEST TO EAST...WITH NO SNOW EXPECTED AFTER MIDNIGHT ON WEDNESDAY.
TEMPS CONTINUE TO TUMBLE TO THE TEENS OR SINGLE DIGITS WEDNESDAY
NIGHT. WINDS 20-25 MPH WITH GUSTS UP TO 30 MPH SLOWLY WEAKEN
OVERNIGHT...BUT EXPECTING WINDCHILLS TO BE BTWN 1 AND -10.
JEE
EXTENDED PERIOD...THURSDAY THROUGH TUESDAY...
MAIN FORECAST CONCERN IN EXTENDED PERIOD DEALS WITH REINFORCEMENT OF
ARCTIC COLD THURSDAY NIGHT/FRIDAY...AND THE POTENTIAL FOR LIGHT SNOW
FRIDAY NIGHT/SATURDAY WITH A COUPLE CLIPPER-TYPE SYSTEMS ON THE BACK
SIDE OF THE RETREATING LOW LEVEL COLD AIR.
MEDIUM RANGE GUIDANCE APPEARS TO BE IN GOOD AGREEMENT AT THE START
OF THE PERIOD THURSDAY MORNING...WITH DEEP SURFACE LOW LIFTING
NORTHEAST ACROSS EASTERN QUEBEC AND DEEP UPPER LEVEL TROUGH ACROSS
MUCH OF EASTERN NORTH AMERICA. ALL OF THE GLOBAL MODELS DEPICT
ANOTHER STRONG SHORT WAVE DIGGING SOUTHEAST ACROSS THE UPPER
MISSISSIPPI VALLEY AND WESTERN GREAT LAKES REGION THROUGH THE DAY...
ACCOMPANIED BY A STRONG PUSH OF COLD ARCTIC AIR WITH 850 MB TEMPS OF
-22 TO -24 C MOVING INTO THE CWA BY THURSDAY EVENING. MODEL
SOUNDINGS AND TIME/HEIGHT SERIES INDICATE DRY MID/UPPER LEVELS AHEAD
OF THIS DIGGING SHORT WAVE...WITH MODEL GENERATED QPF LIMITED TO THE
MID/LOWER MISSOURI RIVER VALLEY INTO THE LOWER OHIO VALLEY THURSDAY
AFTERNOON AND EVENING...THE COMBINATION OF DIGGING VORT...COLD
ADVECTION WITH VERY COLD ARCTIC AIR...AND RELATIVELY MOIST LOW
LEVELS ALL POINT TO THE POTENTIAL FOR AT LEAST SOME FLURRIES ACROSS
THE FORECAST AREA THURSDAY AFTERNOON/EVENING. TEMPS...WHICH SHOULD
ONLY TOP OUT IN THE MID TEENS NORTH AND LOWER 20S SOUTH AFTER
WEDNESDAYS COLD FRONT...SHOULD EASILY FALL TO AROUND/BELOW ZERO
ACROSS NORTH CENTRAL IL BY SUNRISE FRIDAY AND TO PERHAPS THE LOW
POSITIVE SINGLE DIGITS ACROSS THE SOUTH WITH STRONG LOW LEVEL COLD
ADVECTION THURSDAY NIGHT. HAVE TRENDED COLDER TOWARD THE 00Z GEFS
MOS...AND A FEW DEGREES BELOW THAT AROUND ROCKFORD. THIS MAY NOT BE
COLD ENOUGH ESPECIALLY IF SIGNIFICANT SNOW PACK IS IN PLACE AFTER
WEDNESDAY. WINDS SHOULD REMAIN BLUSTERY ESPECIALLY IN THE EVENING
WITH THE ENHANCED GRADIENT TO THE EAST OF THE CANADIAN HIGH BUILDING
SOUTHEAST THROUGH THE PLAINS...SUPPORTING WIND CHILLS -10 TO -20 F
OVERNIGHT.
THE MID-LEVEL SHORT WAVE TROUGH AXIS IS PROGGED TO MOVE OFF TO THE
SOUTHEAST OF THE FORECAST AREA EARLY FRIDAY MORNING...WITH FAIRLY
STRONG HEIGHT RISES DEVELOPING IN ITS WAKE. COLD SURFACE HIGH
PRESSURE CENTER WILL CONTINUE TO PUSH SOUTHEAST THROUGH THE LOWER
OHIO VALLEY INTO TENNESSEE BY EVENING. CORE OF THE COLDEST AIR WILL
SHIFT OFF TO THE EAST/SOUTHEAST BY AFTERNOON...THOUGH COLD MORNING
START AND SHALLOW MIXED LAYER BENEATH SUBSIDENCE INVERSION WILL
ALLOW ONLY MARGINAL MODERATION OF TEMPS AT THE SURFACE. HAVE ALSO
TRENDED COLDER WITH MAXES FRIDAY TOWARD COLDER GFS/GEFS MOS NUMBERS.
NORTHERN EXTENT OF SURFACE RIDGE AXIS MOVES ACROSS THE CWA FRIDAY
EVENING...WITH WARM ADVECTION ALREADY DEVELOPING ON THE WESTERN
PERIPHERY OF THE RETREATING LOW LEVEL COLD AIR DOME. WITH NORTHWEST
FLOW ALOFT ON THE BACK SIDE OF THE DEPARTING LONG-WAVE UPPER TROUGH
THIS SETS THE STAGE FOR A COUPLE OF MODEST SHORT WAVES TO BRING A
COUPLE POTENTIAL PERIODS OF LIGHT SNOW TO THE REGION FRIDAY NIGHT
AND SATURDAY. ECMWF/GFS 12Z RUNS REMAIN IN FAIRLY GOOD AGREEMENT IN
DEVELOPING LIGHT QPF ACROSS THE AREA WITH A WEAK SURFACE LOW MOVING
ACROSS NORTHERN ILLINOIS SATURDAY. UPPER JET CORE THEN SHIFTS SLOWLY
EAST/NORTHEAST ACROSS THE NORTHERN/CENTRAL GREAT LAKES SATURDAY
NIGHT...AS HIGH PRESSURE RIDGE MOVES ACROSS THE REGION THROUGH
SUNDAY. WITH COLD CORE OF UPPER TROUGH OFF TO THE EAST...TEMPS
MODERATE BACK TO MORE SEASONABLE LEVELS SATURDAY (MID-UPPER 20S) AND
PERHAPS A BIT ABOVE (30S) SUNDAY AS WINDS SHIFT SOUTH IN THE
AFTERNOON WEST OF THE RIDGE AXIS. MODERATION LOOKS TO CONTINUE
MONDAY AS ECMWF/GFS REMAIN IN GOOD AGREEMENT IN TAKING AN AREA OF
SURFACE LOW PRESSURE NORTH OF THE CWA ACROSS MN/WI. DRY HIGH
PRESSURE BLOCKS MOISTURE RETURN FROM THE SOUTH FOR THE MOST PART...
WITH NEXT CHANCE OF ORGANIZED PRECIP OCCURRING WITH THE COLD FRONT
ASSOCIATED WITH THIS LOW MONDAY/MONDAY NIGHT...AND MAINLY ACROSS THE
SOUTHEASTERN CWA. GEM MEANWHILE DURING THIS PERIOD BECOMES A COLD
OUTLIER...WITH CONSISTENT ECMWF/GFS SOLUTIONS FAVORED AT THIS
DISTANCE. THIS WOULD INDICATE COOLER/SEASONAL TEMPS RETURN TUESDAY.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 22Z...
* SCATTERED SHOWERS AND THUNDERSTORMS WILL PERSIST UNTIL AROUND
00Z...THEN A MORE SOLID LINE WILL PASS THROUGH THE TERMINALS
WITH A SHORT PERIOD OF PREVAILING RAIN AND THUNDER. AFTER ARND
02Z...WIDESPREAD RAIN WILL PERSIST THROUGH THE EVENING.
* SOUTH WINDS GUSTING TO ARND 20 KT...SHIFTINGTO SWLY WITH GUSTS
TO 25KT WITH THE MORE SOLID LINE OF SHRA/TSRA. WINDS VEERING WYL
AND NWLY THROUGH THE EVENING. AND OVERNIGHT.
* MVFR CONDITIONS PREVAILING THE REMAINDER OF THIS AFTERNOON AND
INTO THE EVENING...WITH OCNL IFR LIKELY. THEN PREVAILING IFR
CIGS THROUGH THE NIGHT.
KREIN
//DISCUSSION...UPDATED 18Z...
A SERIES OF UPPER LEVEL WAVES HAS BEEN MOVING ACROSS THE AREA WITH
PERIODS OF SHRA AND TSRA. THE NEXT OF THESE WAVES IS MOVING OUT OF
THE SOUTHERN PLAINS AT MID DAY AND IS EXPECTED TO BRING A LARGE
AREA OF RA/SHRA WITH EMBEDDED TSRA TO NORTHERN IL AND NORTHWEST IN
LATE THIS AFTERNOON AND THROUGH THE EVENING. HAVE HIGHLIGHTED THE
MOST LIKELY TIME FRAME IN THE TAFS BUT THE TIMING MAY NEED TO BE
ADJUSTED AS DETAILS BECOME MORE CLEAR.
CONDITIONS LOWERING TO IFR OVERNIGHT AS A SURFACE COLD FRONT MOVES
ACROSS THE AREA AND SHIFTS THE WINDS TO WEST TO NORTHWEST. COLDER
AIR BEHIND THE FRONT WILL TURN THE REMAINING PRECIPITATION TO SN
ON WEDNESDAY.
PAW
//ORD AND MDW CONFIDENCE...UPDATED 22Z...
* HIGH CONFIDENCE IN SHOWER AND THUNDERSTORM TREND. MEDIUM
CONFIDENCE IN TIMING OF MORE WIDESPREAD ACTIVITY LATER THIS
EVENING...AND IN CIG/VIS DETAILS.
* HIGH CONFIDENCE IN WIND TREND.
* MEDIUM CONFIDENCE IN IFR TIMING.
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT...VFR.
THURSDAY...VFR.
FRIDAY...CHANCE OF ACCUMULATING SNOW AND MVFR/IFR CONDITIONS AT NIGHT.
SATURDAY...CHANCE OF ACCUMULATING SNOW AND MVFR/IFR CONDITIONS
DURING THE DAY.
SUNDAY...VFR.
MONDAY...VFR.
TRS
&&
.MARINE...
1248 PM CST
SEVERAL WAVES OF LOW PRESSURE WILL RIDE UP A SLOW MOVING COLD
FRONT TONIGHT THROUGH WEDNESDAY AFTERNOON...AS THE FRONT TRAVERSES
LAKE MICHIGAN. STRONG SOUTH TO SOUTHWEST WINDS AHEAD OF THE
FRONT HAVE PROMPTED A SMALL CRAFT ADVISORY FOR THE IL AND IN
NEARSHORE. WINDS WILL SUBSIDE AS THE FRONT APPROACHES THE ILLINOIS
WATERS LATE THIS AFTERNOON...AND THE INDIANA WATERS THIS EVENING.
AREAS OF DENSE FOG ARE POSSIBLE INTO THIS EVENING...MAINLY OVER
THE SOUTH HALF OF THE LAKE...AS UNSEASONABLY MILD AND HUMID AIR
MOVES OVER THE CHILLY WATER.
BEHIND THE COLD FRONT...NORTHWEST WINDS WILL RAMP UP AS THE FINAL
WAVE OF LOW PRESSURE MOVES INTO EASTERN CANADA AND
INTENSIFIES...WHILE STRONG HIGH PRESSURE BUILDS INTO THE NORTHERN
PLAINS. GALE FORCE WINDS WILL DEVELOP BY MID MORNING WEDNESDAY AND
SLOWLY DIMINISH BELOW GALE FORCE THURSDAY MORNING. THE GALE WATCH
WILL BE UPGRADED TO A GALE WARNING WITH THE 300 PM GLFLM ISSUANCE.
STRONG WEST TO NORTHWEST WINDS WILL CONTINUE THROUGH FRIDAY BEFORE
DIMINISHING THIS WEEKEND AS THE HIGH PRESSURE SETTLES OVER THE
SOUTHEAST. FREEZING SPRAY IS LIKELY WEDNESDAY NIGHT AND THURSDAY
DUE TO THE COMBINATION OF STRONG WINDS...LARGE WAVES...AND ARCTIC
AIR OVER THE LAKE.
ALLSOPP
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLOOD WATCH...ILZ003-ILZ004-ILZ008-ILZ010-ILZ011-ILZ019 UNTIL 4
AM WEDNESDAY.
FLOOD WATCH...ILZ005-ILZ006-ILZ012-ILZ013-ILZ014-ILZ020-ILZ021-
ILZ022-ILZ023-ILZ032-ILZ033-ILZ039 UNTIL 4 AM WEDNESDAY.
IN...FLOOD WATCH...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL 4 AM
WEDNESDAY.
LM...DENSE FOG ADVISORY...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-
LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878
UNTIL 10 PM TUESDAY.
GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...9 AM WEDNESDAY TO 6 AM
THURSDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 4 AM WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
320 PM CST TUE JAN 29 2013
.MESOSCALE DISCUSSION...
240 PM CST
THE THREAT FOR HEAVY RAIN DEVELOPING AND POSSIBLY A COUPLE SEVERE
STORMS CONTINUES.
THE LATEST HAND ANALYSIS PLACES THE COLD FRONT JUST PAST THE
MISSISSIPPI RIVER IN NORTHWEST IL WITH A SUBTLE PRE-FRONTAL
TROUGH FROM JUST EAST OF ROCKFORD SOUTH TOWARD PEORIA. THIS PRE-
FRONTAL TROUGH DOES HAVE AN INSTABILITY PLUME AIDED BY LOW TO MID
60S TEMPERATURES...AND LOW-LEVEL CAPE IS ANALYZED NEAR 100 J/KG
WITH AROUND 300-500 J/KG OF SURFACE-BASED CAPE. THIS INSTABILITY
THOUGH IS NOT LINING UP WITH ANY GREAT STORM ACTIVITY.
SATELLITE AND RADAR TRENDS SHOW THAT A LARGE SWATH OF RAIN HAS
EXPANDED FROM MO NORTHEAST THROUGH WESTERN IL AND SOUTHERN
WI...STABILIZING MUCH OF THAT AREA. AT THE FRONT EDGE OF
THIS...NEAR THE PRE-FRONTAL TROUGH...MORE CONVECTIVE-LIKE SHOWERS
ARE PRESENT. THAT CONVECTION ON THE ILX RADAR HAS STRUGGLED TO
BECOME WELL-DEFINED AND HAS MORE OF A QUASI-LINEAR MUSHY LOOK
RIGHT NOW. LIGHTNING HAS BEEN SOMEWHAT SPORADIC AND REALLY HAS
ONLY BEEN SEEN IN THE CLUSTER THAT IS NEARING CHICAGO...POSSIBLY
ASSOCIATED WITH A WARM AIR ADVECTION FLANK AHEAD OF THE SYSTEM.
OVERALL THE TREND HAS BEEN SLIGHTLY DOWN WITH NO LOCAL STORMS
APPROACHING SEVERE LIMITS...AND A FEW 30-37 KT GUSTS OBSERVED. AT
THIS TIME...IT REMAINS QUITE MARGINAL FOR SEVERE WEATHER AND MAY
CONTINUE TO THROUGH MUCH OF THE AFTERNOON AS NO IMMEDIATE STRONG
IMPULSES UPSTREAM ARE EVIDENT.
TOWARD SUNSET AND INTO THIS EVENING...AREAS ALONG AND EAST OF I-55
WILL REMAIN FAVORED FOR STORM ACTIVITY ON THE NOSE OF AN
INCREASING LOW LEVEL JET AND JUST MORE IMPROVED OVERALL FORCING.
EXPLICIT CONVECTIVE MODELS AGREE THIS AREA WILL BE UNDER SOME
STRONGER ACTIVITY THIS EVENING...BUT WHETHER THAT IS TO THE
LIMITS TO FLIRT WITH SEVERE IS LOW CONFIDENCE. THE FORECAST DCAPE
DOES INCREASE TO AROUND 400-500 J/KG ON THE NAM AND THE LOW-LEVEL
SHEAR/HELICITY REMAINS HIGH IN THE STRONG ATMOSPHERIC WINDS. THIS
MAY END UP BEING OUR BEST...ALBEIT NARROW WINDOW FOR SEVERE
WEATHER.
HEAVY RAIN REMAINS THE PRIMARY POTENTIAL HAZARD. WHILE IT IS A
QUASI- LINEAR MUSHY LOOK RIGHT NOW...RAINFALL RATES ARE LIKELY
VERY EFFICIENT IN ANY ACTIVITY AND WILL CONTINUE AS SUCH LATE THIS
AFTERNOON INTO TONIGHT. A PERSISTENT FOCUS IS SEEN IN THE RAP AND
NAM FORECASTS AS DEEP LAYER MOISTURE CONVERGENCE FURTHER INCREASES
TONIGHT AS THE UPPER TROUGH INCHES EASTWARD. WIDESPREAD RAINFALL
AMOUNTS OF ONE TO TWO AND A HALF INCHES LOOK LIKELY...WITH
POTENTIALLY THE HIGHER END AMOUNTS BEING WIDESPREAD. WITH MUCH OF
THIS GOING TOWARD RUNOFF...AT LEAST LOCALIZED PONDING TO POSSIBLE
FLOODING WILL BE LIKELY.
MTF
&&
.DISCUSSION...
318 PM CST
SHORT TERM...REST OF TODAY THROUGH WEDNESDAY NIGHT...
FOR HEADLINES...KEPT FLOOD WATCH AS IS AND NO WINTER HEADLINES ARE
EXPECTED AT THIS TIME.
A DEEP TROUGH LIES ACROSS THE WESTERN US WITH ITS AXIS OVER THE
GREAT PLAINS...WHILE A SURFACE LOW IS OVER ONTARIO. THE SURFACE
LOWS COLD FRONT EXTENDS FROM THE LOW THROUGH CENTRAL WI TO ALONG THE
MISSISSIPPI RIVER...AND IT IS SLOWLY MAKING ITS WAY INTO WESTERN
IL. THE TEMPERATURE GRADIENT ACROSS THE FRONT IS RATHER IMPRESSIVE
WITH 60 DEGREES IN PERU IL AND 38 DEGREES IN OTTUMWA IA...WITH JUST
176 MILES BETWEEN THE TWO CITIES. SHOWERS AND THUNDERSTORMS HAVE
SPREAD INTO NORTHERN IL AHEAD OF THE COLD FRONT AND WILL CONTINUE TO
SPREAD ACROSS THE CWA THIS AFTERNOON/EARLY EVENING. INDIVIDUAL CELLS
HAVE BEEN CLOCKED AT 50-60 KT MOVING FROM THE SOUTHWEST TO THE
NORTHEAST. SEVERE STORMS ARE STILL POSSIBLE THIS AFTERNOON...FOR
MORE INFORMATION ON THE SEVERE WEATHER OUTLOOK AND RELATED
PARAMETERS PLEASE SEE THE MESOSCALE DISCUSSION ABOVE.
PWAT VALUES WILL BE IN EXCESS OF 1-1.5 INCHES THIS AFTERNOON/EVENING
WITH DEWPOINTS CURRENTLY IN THE UPPER 50S TO LOW 60S FALLING
OVERNIGHT. FLOW THROUGHOUT THE ATMOSPHERIC COLUMN IS ROUGHLY
PARALLEL TO THE FRONT WHICH WILL INHIBIT THE FRONT FROM RAPIDLY
PROGRESSING THROUGH THE CWA. TRAINING WILL ALSO BECOME AN ISSUE
ALONG THE FRONT ALLOWING FOR IMPRESSIVE RAIN TOTALS. THE UPPER
LEVEL JET STRETCHES FROM TEXAS THROUGH MINNESOTA BEFORE CURVING
TOWARD QUEBEC. THE RIGHT JET ENTRANCE REGION LIES OVER SOUTHWEST
WI/NORTHWEST IL ALMOST COLLOCATED WITH THE FRONT WHICH WILL CONTINUE
TO SUPPORT THUNDERSTORM AND SHOWER FORMATION. BASED ON WHAT HAS
PASSED OVER THE OFFICE THIS AFTERNOON...SOME OF THESE SHOWERS/STORMS
WILL PRODUCE BRIEF INTENSE DOWNPOURS. THE JET AND FRONT CONTINUE
ACROSS THE CWA TONIGHT WITH THE SOUTHERN JET STREAKS LEFT EXIT
REGION POSSIBLY COUPLING WITH THE FRONT. AS SUCH EXPECTING PERIODS
OF HEAVY RAIN TO CONTINUE OVERNIGHT. WHEN ALL IS SAID AND
DONE...THINKING 1.5-2.5 INCHES OF RAIN ARE POSSIBLE ACROSS THE
AREA. LOCALLY HIGHER AMOUNTS ARE CERTAINLY POSSIBLE.
QUICKLY CHECKING THE OFFICES SOIL TEMPS...2 AND 4 INCHES BELOW THE
SURFACE ARE ABOVE FREEZING AT 35 DEGREES WHILE 8 INCHES IS STILL
FROZEN AT 27 DEGREES. AS SUCH EXPECTING PONDING OF WATER IN THE
TYPICAL LOW LYING SPOTS...SINCE THE SOIL WILL NOT BE ABLE TO TAKE IN
AS MUCH WATER AS USUAL. THEREFORE MADE NO ADJUSTMENTS TO THE FLOOD
WATCH.
TEMPS WILL BEGIN TO FALL OVERNIGHT WITH LOWS IN THE LOW 30S NEAR RFD
TO ARND 50 NEAR RENSSELAER.
WEDNESDAY...
TEMPS WILL CONTINUE TO FALL WEDNESDAY MORNING WITH PRECIP
TRANSITIONING TO SNOW AS A SWATH OF MOISTURE ASSOCIATED WITH THE 700
MB LOW SURGES NORTH. SOUNDINGS INDICATE A BRIEF PERIOD OF SLEET IS
POSSIBLE DURING THE TRANSITION BUT NOT EXPECTING ANY SIGNIFICANT
SLEET ACCUMULATION. EXPECTING AREAS AROUND RFD TO CHANGE OVER TO
SNOW BEFORE 8AM...CHICAGO AROUND 3PM...AND NW INDIANA 4-6PM.
FOR SNOW TOTALS...EXPECTING THE HIGHEST TOTALS IN FAR NW IL IN
WINNEBAGO AND OGLE COUNTIES. THE NAM IS MUCH MORE EXCITED THAN THE
GFS ABOUT THE SNOW POTENTIAL BUT BOTH MODELS SHOW THE SAME SET UP
THAT IS FAVORABLE FOR MESOSCALE SNOW BANDS. 850-700 MB
FRONTOGENESIS MOVES OVER NW IL/E IA EARLY WEDNESDAY MORNING WITH EPV
VALUES BELOW 0 JUST ABOVE IT...INDICATING LOCALIZED INTENSE FORCING
AND SYMMETRIC INSTABILITY. HOWEVER EXPECTING TEMPS TO BE ABOVE
FREEZING AT THIS POINT. THE FRONTOGENESIS AND INSTABILITY SHIFT
EASTWARD THROUGH THE MORNING AND THEN WEAKEN AFTER NOON. THE LEFT
JET EXIT REGION OF THE UPPER LEVEL JET WILL ALSO BE OVER NORTHERN IL
THROUGH WEDNESDAY AFTERNOON SO SYNOPTIC-SCALE LIFT SHOULD NOT BE AN
ISSUE.
WHILE MESOSCALE BANDS OF RAIN OR SNOW ARE VERY LIKELY
TOMORROW...THESE FEATURES ARE HARD TO PINPOINT EVEN THIS FAR OUT.
THEREFORE WENT WITH 3-5 INCHES OF SNOW OVER WINNEBAGO AND OGLE
COUNTIES TOMORROW...BUT THIS NUMBER COULD EASILY BE HIGHER IF A BAND
OF SNOW SETS UP. THE BIG QUESTIONS ARE WILL THE BEST FORCING ALIGN
WITH SNOW OR RAIN...HOW LONG WILL THE FORCING LAST...AND WHERE WILL
THE MESOSCALE BAND SET UP.
AS MENTIONED BEFORE...THE FRONTOGENESIS WEAKENS AND STABILITY
INCREASES IN THE AFTERNOON AS THE SNOW SPREADS ACROSS THE REST OF
THE CWA. SO INTENSE MESOSCALE BANDS ARE NOT AS LIKELY...BUT FORCING
FROM THE UPPER LEVEL JET STILL LOOKS FAVORABLE FOR A LITTLE SNOW. AS
SUCH EXPECTING 1 TO 3 INCHES OF SNOW ACROSS BOONE AND MCHENRY
COUNTIES...AND THEN AN INCH OR LESS EVERYWHERE ELSE. SNOW ENDS FROM
WEST TO EAST...WITH NO SNOW EXPECTED AFTER MIDNIGHT ON WEDNESDAY.
TEMPS CONTINUE TO TUMBLE TO THE TEENS OR SINGLE DIGITS WEDNESDAY
NIGHT. WINDS 20-25 MPH WITH GUSTS UP TO 30 MPH SLOWLY WEAKEN
OVERNIGHT...BUT EXPECTING WINDCHILLS TO BE BTWN 1 AND -10.
JEE
EXTENDED PERIOD...THURSDAY THROUGH TUESDAY...
MAIN FORECAST CONCERN IN EXTENDED PERIOD DEALS WITH REINFORCEMENT OF
ARCTIC COLD THURSDAY NIGHT/FRIDAY...AND THE POTENTIAL FOR LIGHT SNOW
FRIDAY NIGHT/SATURDAY WITH A COUPLE CLIPPER-TYPE SYSTEMS ON THE BACK
SIDE OF THE RETREATING LOW LEVEL COLD AIR.
MEDIUM RANGE GUIDANCE APPEARS TO BE IN GOOD AGREEMENT AT THE START
OF THE PERIOD THURSDAY MORNING...WITH DEEP SURFACE LOW LIFTING
NORTHEAST ACROSS EASTERN QUEBEC AND DEEP UPPER LEVEL TROUGH ACROSS
MUCH OF EASTERN NORTH AMERICA. ALL OF THE GLOBAL MODELS DEPICT
ANOTHER STRONG SHORT WAVE DIGGING SOUTHEAST ACROSS THE UPPER
MISSISSIPPI VALLEY AND WESTERN GREAT LAKES REGION THROUGH THE DAY...
ACCOMPANIED BY A STRONG PUSH OF COLD ARCTIC AIR WITH 850 MB TEMPS OF
-22 TO -24 C MOVING INTO THE CWA BY THURSDAY EVENING. MODEL
SOUNDINGS AND TIME/HEIGHT SERIES INDICATE DRY MID/UPPER LEVELS AHEAD
OF THIS DIGGING SHORT WAVE...WITH MODEL GENERATED QPF LIMITED TO THE
MID/LOWER MISSOURI RIVER VALLEY INTO THE LOWER OHIO VALLEY THURSDAY
AFTERNOON AND EVENING...THE COMBINATION OF DIGGING VORT...COLD
ADVECTION WITH VERY COLD ARCTIC AIR...AND RELATIVELY MOIST LOW
LEVELS ALL POINT TO THE POTENTIAL FOR AT LEAST SOME FLURRIES ACROSS
THE FORECAST AREA THURSDAY AFTERNOON/EVENING. TEMPS...WHICH SHOULD
ONLY TOP OUT IN THE MID TEENS NORTH AND LOWER 20S SOUTH AFTER
WEDNESDAYS COLD FRONT...SHOULD EASILY FALL TO AROUND/BELOW ZERO
ACROSS NORTH CENTRAL IL BY SUNRISE FRIDAY AND TO PERHAPS THE LOW
POSITIVE SINGLE DIGITS ACROSS THE SOUTH WITH STRONG LOW LEVEL COLD
ADVECTION THURSDAY NIGHT. HAVE TRENDED COLDER TOWARD THE 00Z GEFS
MOS...AND A FEW DEGREES BELOW THAT AROUND ROCKFORD. THIS MAY NOT BE
COLD ENOUGH ESPECIALLY IF SIGNIFICANT SNOW PACK IS IN PLACE AFTER
WEDNESDAY. WINDS SHOULD REMAIN BLUSTERY ESPECIALLY IN THE EVENING
WITH THE ENHANCED GRADIENT TO THE EAST OF THE CANADIAN HIGH BUILDING
SOUTHEAST THROUGH THE PLAINS...SUPPORTING WIND CHILLS -10 TO -20 F
OVERNIGHT.
THE MID-LEVEL SHORT WAVE TROUGH AXIS IS PROGGED TO MOVE OFF TO THE
SOUTHEAST OF THE FORECAST AREA EARLY FRIDAY MORNING...WITH FAIRLY
STRONG HEIGHT RISES DEVELOPING IN ITS WAKE. COLD SURFACE HIGH
PRESSURE CENTER WILL CONTINUE TO PUSH SOUTHEAST THROUGH THE LOWER
OHIO VALLEY INTO TENNESSEE BY EVENING. CORE OF THE COLDEST AIR WILL
SHIFT OFF TO THE EAST/SOUTHEAST BY AFTERNOON...THOUGH COLD MORNING
START AND SHALLOW MIXED LAYER BENEATH SUBSIDENCE INVERSION WILL
ALLOW ONLY MARGINAL MODERATION OF TEMPS AT THE SURFACE. HAVE ALSO
TRENDED COLDER WITH MAXES FRIDAY TOWARD COLDER GFS/GEFS MOS NUMBERS.
NORTHERN EXTENT OF SURFACE RIDGE AXIS MOVES ACROSS THE CWA FRIDAY
EVENING...WITH WARM ADVECTION ALREADY DEVELOPING ON THE WESTERN
PERIPHERY OF THE RETREATING LOW LEVEL COLD AIR DOME. WITH NORTHWEST
FLOW ALOFT ON THE BACK SIDE OF THE DEPARTING LONG-WAVE UPPER TROUGH
THIS SETS THE STAGE FOR A COUPLE OF MODEST SHORT WAVES TO BRING A
COUPLE POTENTIAL PERIODS OF LIGHT SNOW TO THE REGION FRIDAY NIGHT
AND SATURDAY. ECMWF/GFS 12Z RUNS REMAIN IN FAIRLY GOOD AGREEMENT IN
DEVELOPING LIGHT QPF ACROSS THE AREA WITH A WEAK SURFACE LOW MOVING
ACROSS NORTHERN ILLINOIS SATURDAY. UPPER JET CORE THEN SHIFTS SLOWLY
EAST/NORTHEAST ACROSS THE NORTHERN/CENTRAL GREAT LAKES SATURDAY
NIGHT...AS HIGH PRESSURE RIDGE MOVES ACROSS THE REGION THROUGH
SUNDAY. WITH COLD CORE OF UPPER TROUGH OFF TO THE EAST...TEMPS
MODERATE BACK TO MORE SEASONABLE LEVELS SATURDAY (MID-UPPER 20S) AND
PERHAPS A BIT ABOVE (30S) SUNDAY AS WINDS SHIFT SOUTH IN THE
AFTERNOON WEST OF THE RIDGE AXIS. MODERATION LOOKS TO CONTINUE
MONDAY AS ECMWF/GFS REMAIN IN GOOD AGREEMENT IN TAKING AN AREA OF
SURFACE LOW PRESSURE NORTH OF THE CWA ACROSS MN/WI. DRY HIGH
PRESSURE BLOCKS MOISTURE RETURN FROM THE SOUTH FOR THE MOST PART...
WITH NEXT CHANCE OF ORGANIZED PRECIP OCCURRING WITH THE COLD FRONT
ASSOCIATED WITH THIS LOW MONDAY/MONDAY NIGHT...AND MAINLY ACROSS THE
SOUTHEASTERN CWA. GEM MEANWHILE DURING THIS PERIOD BECOMES A COLD
OUTLIER...WITH CONSISTENT ECMWF/GFS SOLUTIONS FAVORED AT THIS
DISTANCE. THIS WOULD INDICATE COOLER/SEASONAL TEMPS RETURN TUESDAY.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* AN AREA OF SHOWERS AND THUNDERSTORMS APPROACHING ORD AND MDW
FROM THE SOUTHWEST AT 20Z. MORE WIDESPREAD RAIN AND EMBEDDED
THUNDERSTORMS MOVING IN LATER THIS AFTERNOON AND THROUGH THE
EVENING.
* SOUTH TO SOUTHWEST WINDS..GUSTING TO 20-25 KT THROUGH THE
AFTERNOON. WINDS SHIFT TO WEST AND NORTHWEST LATE TONIGHT AS A
COLD FRONT MOVES ACROSS THE AREA.
* MVFR CONDITIONS PREVAILING THIS AFTERNOON AND EVENING. IFR
CONDITIONS TONIGHT.
PAW
//DISCUSSION...UPDATED 18Z...
A SERIES OF UPPER LEVEL WAVES HAS BEEN MOVING ACROSS THE AREA WITH
PERIODS OF SHRA AND TSRA. THE NEXT OF THESE WAVES IS MOVING OUT OF
THE SOUTHERN PLAINS AT MID DAY AND IS EXPECTED TO BRING A LARGE
AREA OF RA/SHRA WITH EMBEDDED TSRA TO NORTHERN IL AND NORTHWEST IN
LATE THIS AFTERNOON AND THROUGH THE EVENING. HAVE HIGHLIGHTED THE
MOST LIKELY TIME FRAME IN THE TAFS BUT THE TIMING MAY NEED TO BE
ADJUSTED AS DETAILS BECOME MORE CLEAR.
CONDITIONS LOWERING TO IFR OVERNIGHT AS A SURFACE COLD FRONT MOVES
ACROSS THE AREA AND SHIFTS THE WINDS TO WEST TO NORTHWEST. COLDER
AIR BEHIND THE FRONT WILL TURN THE REMAINING PRECIPITATION TO SN
ON WEDNESDAY.
PAW
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE IN SHOWER AND THUNDERSTORM TREND. MEDIUM
CONFIDENCE IN TIMING OF MORE WIDESPREAD ACTIVITY LATER THIS
AFTERNOON AND EVENING...AND IN CEILING/VIS DETAILS.
* HIGH CONFIDENCE IN WIND TREND.
* MEDIUM CONFIDENCE IN IFR TIMING.
PAW
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT...VFR.
THURSDAY...VFR.
FRIDAY...CHANCE OF ACCUMULATING SNOW AND MVFR/IFR CONDITIONS AT NIGHT.
SATURDAY...CHANCE OF ACCUMULATING SNOW AND MVFR/IFR CONDITIONS
DURING THE DAY.
SUNDAY...VFR.
MONDAY...VFR.
TRS
&&
.MARINE...
1248 PM CST
SEVERAL WAVES OF LOW PRESSURE WILL RIDE UP A SLOW MOVING COLD
FRONT TONIGHT THROUGH WEDNESDAY AFTERNOON...AS THE FRONT TRAVERSES
LAKE MICHIGAN. STRONG SOUTH TO SOUTHWEST WINDS AHEAD OF THE
FRONT HAVE PROMPTED A SMALL CRAFT ADVISORY FOR THE IL AND IN
NEARSHORE. WINDS WILL SUBSIDE AS THE FRONT APPROACHES THE ILLINOIS
WATERS LATE THIS AFTERNOON...AND THE INDIANA WATERS THIS EVENING.
AREAS OF DENSE FOG ARE POSSIBLE INTO THIS EVENING...MAINLY OVER
THE SOUTH HALF OF THE LAKE...AS UNSEASONABLY MILD AND HUMID AIR
MOVES OVER THE CHILLY WATER.
BEHIND THE COLD FRONT...NORTHWEST WINDS WILL RAMP UP AS THE FINAL
WAVE OF LOW PRESSURE MOVES INTO EASTERN CANADA AND
INTENSIFIES...WHILE STRONG HIGH PRESSURE BUILDS INTO THE NORTHERN
PLAINS. GALE FORCE WINDS WILL DEVELOP BY MID MORNING WEDNESDAY AND
SLOWLY DIMINISH BELOW GALE FORCE THURSDAY MORNING. THE GALE WATCH
WILL BE UPGRADED TO A GALE WARNING WITH THE 300 PM GLFLM ISSUANCE.
STRONG WEST TO NORTHWEST WINDS WILL CONTINUE THROUGH FRIDAY BEFORE
DIMINISHING THIS WEEKEND AS THE HIGH PRESSURE SETTLES OVER THE
SOUTHEAST. FREEZING SPRAY IS LIKELY WEDNESDAY NIGHT AND THURSDAY
DUE TO THE COMBINATION OF STRONG WINDS...LARGE WAVES...AND ARCTIC
AIR OVER THE LAKE.
ALLSOPP
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLOOD WATCH...ILZ003-ILZ004-ILZ008-ILZ010-ILZ011-ILZ019 UNTIL 4
AM WEDNESDAY.
FLOOD WATCH...ILZ005-ILZ006-ILZ012-ILZ013-ILZ014-ILZ020-ILZ021-
ILZ022-ILZ023-ILZ032-ILZ033-ILZ039 UNTIL 4 AM WEDNESDAY.
IN...FLOOD WATCH...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL 4 AM
WEDNESDAY.
LM...DENSE FOG ADVISORY...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-
LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878
UNTIL 10 PM TUESDAY.
GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...9 AM WEDNESDAY TO 6 AM
THURSDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 4 AM WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS CHICAGO/ROMEOVILLE IL
245 PM CST TUE JAN 29 2013
.MESOSCALE DISCUSSION...
240 PM CST
THE THREAT FOR HEAVY RAIN DEVELOPING AND POSSIBLY A COUPLE SEVERE
STORMS CONTINUES.
THE LATEST HAND ANALYSIS PLACES THE COLD FRONT JUST PAST THE
MISSISSIPPI RIVER IN NORTHWEST IL WITH A SUBTLE PRE-FRONTAL
TROUGH FROM JUST EAST OF ROCKFORD SOUTH TOWARD PEORIA. THIS PRE-
FRONTAL TROUGH DOES HAVE AN INSTABILITY PLUME AIDED BY LOW TO MID
60S TEMPERATURES...AND LOW-LEVEL CAPE IS ANALYZED NEAR 100 J/KG
WITH AROUND 300-500 J/KG OF SURFACE-BASED CAPE. THIS INSTABILITY
THOUGH IS NOT LINING UP WITH ANY GREAT STORM ACTIVITY.
SATELLITE AND RADAR TRENDS SHOW THAT A LARGE SWATH OF RAIN HAS
EXPANDED FROM MO NORTHEAST THROUGH WESTERN IL AND SOUTHERN
WI...STABILIZING MUCH OF THAT AREA. AT THE FRONT EDGE OF
THIS...NEAR THE PRE-FRONTAL TROUGH...MORE CONVECTIVE-LIKE SHOWERS
ARE PRESENT. THAT CONVECTION ON THE ILX RADAR HAS STRUGGLED TO
BECOME WELL-DEFINED AND HAS MORE OF A QUASI-LINEAR MUSHY LOOK
RIGHT NOW. LIGHTNING HAS BEEN SOMEWHAT SPORADIC AND REALLY HAS
ONLY BEEN SEEN IN THE CLUSTER THAT IS NEARING CHICAGO...POSSIBLY
ASSOCIATED WITH A WARM AIR ADVECTION FLANK AHEAD OF THE SYSTEM.
OVERALL THE TREND HAS BEEN SLIGHTLY DOWN WITH NO LOCAL STORMS
APPROACHING SEVERE LIMITS...AND A FEW 30-37 KT GUSTS OBSERVED. AT
THIS TIME...IT REMAINS QUITE MARGINAL FOR SEVERE WEATHER AND MAY
CONTINUE TO THROUGH MUCH OF THE AFTERNOON AS NO IMMEDIATE STRONG
IMPULSES UPSTREAM ARE EVIDENT.
TOWARD SUNSET AND INTO THIS EVENING...AREAS ALONG AND EAST OF I-55
WILL REMAIN FAVORED FOR STORM ACTIVITY ON THE NOSE OF AN
INCREASING LOW LEVEL JET AND JUST MORE IMPROVED OVERALL FORCING.
EXPLICIT CONVECTIVE MODELS AGREE THIS AREA WILL BE UNDER SOME
STRONGER ACTIVITY THIS EVENING...BUT WHETHER THAT IS TO THE
LIMITS TO FLIRT WITH SEVERE IS LOW CONFIDENCE. THE FORECAST DCAPE
DOES INCREASE TO AROUND 400-500 J/KG ON THE NAM AND THE LOW-LEVEL
SHEAR/HELICITY REMAINS HIGH IN THE STRONG ATMOSPHERIC WINDS. THIS
MAY END UP BEING OUR BEST...ALBEIT NARROW WINDOW FOR SEVERE
WEATHER.
HEAVY RAIN REMAINS THE PRIMARY POTENTIAL HAZARD. WHILE IT IS A
QUASI- LINEAR MUSHY LOOK RIGHT NOW...RAINFALL RATES ARE LIKELY
VERY EFFICIENT IN ANY ACTIVITY AND WILL CONTINUE AS SUCH LATE THIS
AFTERNOON INTO TONIGHT. A PERSISTENT FOCUS IS SEEN IN THE RAP AND
NAM FORECASTS AS DEEP LAYER MOISTURE CONVERGENCE FURTHER INCREASES
TONIGHT AS THE UPPER TROUGH INCHES EASTWARD. WIDESPREAD RAINFALL
AMOUNTS OF ONE TO TWO AND A HALF INCHES LOOK LIKELY...WITH
POTENTIALLY THE HIGHER END AMOUNTS BEING WIDESPREAD. WITH MUCH OF
THIS GOING TOWARD RUNOFF...AT LEAST LOCALIZED PONDING TO POSSIBLE
FLOODING WILL BE LIKELY.
MTF
&&
.DISCUSSION...
352 AM CST
...RECORD SHATTERING WARMTH LIKELY TODAY WITH HEAVY AND POTENTIALLY
FLOODING RAINS EXPECTED LATER TODAY AND TONIGHT...
THE MOTHER OF ALL WARM FRONTS IS CHARGING NORTH THROUGH THE AREA AT
THIS TIME...WITH TEMPERATURES SOARING RECORD OR NEAR RECORD LEVELS
IN THE MIDDLE OF THE NIGHT BEHIND THIS WARM FRONT. EQUALLY AS
IMPRESSIVE IS THE MOISTURE CONTENT OF THE AIR MASS SPREADING NORTH
INTO THE AREA WITH DEW POINTS CLIMBING INTO THE MID TO UPPER
50S...WHICH IN MANY CASES EXCEED DAILY RECORD HIGH TEMPERATURES.
HIGH TEMP FORECAST FOR TODAY IS TRICKY AS MOST AREAS WILL BE NEAR
60F AT SUNRISE...THOUGH THERE WILL LIKELY BE SCTD SHOWERS AND
THUNDERSTORMS TODAY ALSO EXPECT MANY DRY HOURS WHICH COULD EASILY
ALLOW FOR AT LEAST A 4F+ RISE IN TEMPS WHICH PUTS HIGHS RIVALING ALL
TIME RECORDS FOR THE MONTH OF JANUARY...WITH ANY BREAKS FOR SUNSHINE
ONLY INCREASING THE CHANCE FOR AN ALL TIME RECORD. THE AIR MASS
MOVING IN PRODUCED MID TO UPPER 70S OVER MO AND SW IL MONDAY
AFTERNOON...SO NOT TERRIBLY FAR FETCHED TO FORECAST MID 60S UP HERE
EVEN WITH WIDELY SCTD CONVECTION AROUND.
PRECIPITATION-WISE WIDELY SCATTERED SHOWERS AND THUNDERSTORMS ARE
POSSIBLE AT JUST ABOUT ANY POINT IN TIME TODAY AS SUBTLE AND
INDISTINGUISHABLE DISTURBANCES IN THE SW FLOW COULD KICK OFF
CONVECTION. HOWEVER...WOULD EXPECT MAJORITY OF THE DAY TO BE DRY IN
MOST AREAS UNTIL THE MORE SIGNIFICANT SHORTWAVE APPROACHES WESTERN
CWA LATE THIS AFTERNOON WITH MORE WIDESPREAD AND VIGOROUS
DEVELOPMENT OF SHOWERS AND THUNDERSTORMS UPSTREAM MOVING INTO THE
CWA LATER THIS AFTERNOON. CERTAINLY WITH DEW POINTS NEAR 60F IN
JANUARY AND SEASONABLY EXTREME SHEAR AM RELUCTANT TO DISCOUNT THE
SEVERE WEATHER THREAT...THOUGH THE VERY MOIST ENVIRONMENT SHOULD
FEATURE RATHER MODEST/WEAK LAPSE RATES...SO UNLESS WE GET SOME
SUNSHINE AND BONUS HEATING WOULD GENERALLY THINK THAT INSTABILITY
WILL BE TOO MEAGER FOR THERE TO BE A SIGNIFICANT SEVERE THREAT.
HOWEVER...MUCH LIKE JAN 2008...SHEAR IS EXTREME SO IF WE DO REALIZE
ANY APPRECIABLE INSTABILITY TODAY THEN ALL BETS WOULD BE OFF AND
THERE WOULD BE A DMG WIND AND POSSIBLY EVEN A TORNADO THREAT.
THE SEVERE THREAT LOOKS VERY CONDITIONAL...HOWEVER THE HEAVY RAIN
THREAT LOOKS QUITE HIGH. PRETTY MUCH ANY VARIABLE YOU COULD LOOK AT
TO DIAGNOSE A COLD SEASON HEAVY RAIN THREAT IS NEAR OR EXCEEDING
RECORD LEVELS. PWATS ARE FORECAST TO REACH RECORD LEVELS OVER 1.3
INCHES BY THIS EVENING...WHICH IS OVER 300% OF NORMAL AND COULD EVEN
APPROACH 400% OF NORMAL. LOW/MID LEVEL FLOW WILL BACK AHEAD OF THE
APPROACHING TROUGH AS IT BECOMING MORE NEUTRALLY TILTED...WHICH
SHOULD RESULT IN LONGER RESIDENCE TIME OF THE LARGE BAND OF RAIN AND
CONVECTION IN THE WARM CONVEYOR BELT AS FLOW ALOFT BECOMES MORE
ALIGNED WITH THE LOW LEVEL FRONTAL BOUNDARY. HPC`S STANDARDIZED
ANOMALIES PAGE SHOWS 850MB MOISTURE TRANSPORT VALUES EXCEEDING 6
STANDARD DEVIATIONS ABOVE AVERAGE...OR IN OTHER WORDS NEARLY UNHEARD
OF PROPORTIONS. FEEL THAT WIDESPREAD 1-2" RAINFALL TOTALS ARE LIKELY
WITH 3"+ TOTALS NOT FAR FETCHED...AND WITH DEEP FROZEN GROUND THE
FLOOD POTENTIAL LOOKS HIGH DESPITE BELOW AVG STREAM FLOW HEADING
INTO THE EVENT. HAVE EXPAND THE FFA TO INCLUDE ENTIRE CWA AND
DELAYED START TIME UNTIL TONIGHT FOR CHGO AND NW INDIANA.
MODELS CONTINUE TO TREND SLOWER WITH THE MOVEMENT OF THE WHOLE UPPER
TROUGH WHICH REQUIRED SOME ADJUSTMENTS TO THE GRIDS TO LINGER PRECIP
LATER INTO TONIGHT AND DELAY THE ARRIVAL OF THE COLD AIR AND
SUBSEQUENT CHANGE OVER OF ANY LINGERING PRECIP. THE SLOW MOVING
STRONG COLD FRONT WILL DEMARK THE PATH THAT THE CONGA LINE OF SFC
LOWS WILL TAKE WITH 00Z GUIDANCE A BIT MORE ROBUST WITH THE WAVE
PROGGED TO MOVE UP THE FRONT INTO THE GREAT LAKES TOMORROW. WHILE
STILL A GREAT DEAL OF VARIABILITY...GUIDANCE IS MORE BULLISH WITH
DEVELOPING A DEFORMATION BAND/TROWAL WITH ACCUMULATING SNOW
POTENTIAL TO THE NORTHWEST OF THE LOW TRACK. AT THIS POINT IT WOULD
SEEM THE BEST THREAT OF ACCUMULATING SNOW WOULD BE OVER FAR NW IL
NORTHEAST INTO WI AND MICHIGAN...BUT OUR FAR NW CWA COULD BE CLOSE
ENOUGH FOR A GLANCING BLOW OF ACCUMULATING SNOW. GIVEN LOW
CONFIDENCE HAVE KEPT SNOWFALL AMOUNTS MODEST FOR NOW BUT NUDGE POPS
UP TO LIKELY. MID LEVEL DRY INTRUSION WOULD SEEM TO FAVOR KEEPING
MEASURABLE PRECIP CHANCES LOWER OVER THE MAJORITY OF THE CWA BY THE
TIME TEMPS COOL ENOUGH FOR A CHANGE OVER TO SNOW. THIS IS A VERY
DYNAMIC TROUGH AND FORECAST CONFIDENCE TOMORROW IS LOW SO STAY
TUNED...
PROGRESSIVELY COLDER AIR FILTERS INTO THE REGION WITH FALLING TEMPS
WEDNESDAY AND WEDNESDAY NIGHT. LACK OF SNOW COVER AND LINGERING
CLOUDS/WINDS SHOULD KEEP TEMPS A BIT MORE MODERATE THAN WHAT AN AIR
MASS OF THIS MAGNITUDE WOULD NORMALLY PRODUCE. IT WILL STILL BE A
MAJOR SHOCK TO THE SYSTEM GOING FROM TEMPS NOT FAR FROM 70 TO NEAR 0
OVER NW COUNTIES IN A 48 HOUR PERIOD. CLIPPER STILL LOOKS TO BE IN
THE NEIGHBORHOOD FRIDAY NIGHT INTO SATURDAY AND COULD LAY DOWN A
SWATH OF ACCUMULATING SNOW SOMEWHERE IN THE MIDWEST...BUT FAR TOO
FAR OUT TO PIN POINT A TRACK YET. MODERATING TEMPS ARE EXPECTED
LATER INTO THE WEEKEND INTO NEXT WEEK THOUGH NOTHING LIKE WHAT WE`LL
EXPERIENCE TODAY.
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* AN AREA OF SHOWERS AND THUNDERSTORMS APPROACHING ORD AND MDW
FROM THE SOUTHWEST AT 20Z. MORE WIDESPREAD RAIN AND EMBEDDED
THUNDERSTORMS MOVING IN LATER THIS AFTERNOON AND THROUGH THE
EVENING.
* SOUTH TO SOUTHWEST WINDS..GUSTING TO 20-25 KT THROUGH THE
AFTERNOON. WINDS SHIFT TO WEST AND NORTHWEST LATE TONIGHT AS A
COLD FRONT MOVES ACROSS THE AREA.
* MVFR CONDITIONS PREVAILING THIS AFTERNOON AND EVENING. IFR
CONDITIONS TONIGHT.
PAW
//DISCUSSION...UPDATED 18Z...
A SERIES OF UPPER LEVEL WAVES HAS BEEN MOVING ACROSS THE AREA WITH
PERIODS OF SHRA AND TSRA. THE NEXT OF THESE WAVES IS MOVING OUT OF
THE SOUTHERN PLAINS AT MID DAY AND IS EXPECTED TO BRING A LARGE
AREA OF RA/SHRA WITH EMBEDDED TSRA TO NORTHERN IL AND NORTHWEST IN
LATE THIS AFTERNOON AND THROUGH THE EVENING. HAVE HIGHLIGHTED THE
MOST LIKELY TIME FRAME IN THE TAFS BUT THE TIMING MAY NEED TO BE
ADJUSTED AS DETAILS BECOME MORE CLEAR.
CONDITIONS LOWERING TO IFR OVERNIGHT AS A SURFACE COLD FRONT MOVES
ACROSS THE AREA AND SHIFTS THE WINDS TO WEST TO NORTHWEST. COLDER
AIR BEHIND THE FRONT WILL TURN THE REMAINING PRECIPITATION TO SN
ON WEDNESDAY.
PAW
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE IN SHOWER AND THUNDERSTORM TREND. MEDIUM
CONFIDENCE IN TIMING OF MORE WIDESPREAD ACTIVITY LATER THIS
AFTERNOON AND EVENING...AND IN CEILING/VIS DETAILS.
* HIGH CONFIDENCE IN WIND TREND.
* MEDIUM CONFIDENCE IN IFR TIMING.
PAW
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT...VFR.
THURSDAY...VFR.
FRIDAY...CHANCE OF ACCUMULATING SNOW AND MVFR/IFR CONDITIONS AT NIGHT.
SATURDAY...CHANCE OF ACCUMULATING SNOW AND MVFR/IFR CONDITIONS
DURING THE DAY.
SUNDAY...VFR.
MONDAY...VFR.
TRS
&&
.MARINE...
1248 PM CST
SEVERAL WAVES OF LOW PRESSURE WILL RIDE UP A SLOW MOVING COLD
FRONT TONIGHT THROUGH WEDNESDAY AFTERNOON...AS THE FRONT TRAVERSES
LAKE MICHHIGAN. STRONG SOUTH TO SOUTHWEST WINDS AHEAD OF THE
FRONT HAVE PROMPTED A SMALL CRAFT ADVISORY FOR THE IL AND IN
NEARSHORE. WINDS WILL SUBSIDE AS THE FRONT APPROACHES THE ILLINOIS
WATERS LATE THIS AFTERNOON...AND THE INDIANA WATERS THIS EVENING.
AREAS OF DENSE FOG ARE POSSIBLE INTO THIS EVENING...MAINLY OVER
THE SOUTH HALF OF THE LAKE...AS UNSEASONABLY MILD AND HUMID AIR
MOVES OVER THE CHILLY WATER.
BEHIND THE COLD FRONT...NORTHWEST WINDS WILL RAMP UP AS THE FINAL
WAVE OF LOW PRESSURE MOVES INTO EASTERN CANADA AND
INTENSIFIES...WHILE STRONG HIGH PRESSURE BUILDS INTO THE NORTHERN
PLAINS. GALE FORCE WINDS WILL DEVELOP BY MID MORNING WEDNESDAY AND
SLOWLY DIMINISH BELOW GALE FORCE THURSDAY MORNING. THE GALE WATCH
WILL BE UPGRADED TO A GALE WARNING WITH THE 300 PM GLFLM ISSUANCE.
STRONG WEST TO NORTHWEST WINDS WILL CONTINUE THROUGH FRIDAY BEFORE
DIMINISHING THIS WEEKEND AS THE HIGH PRESSURE SETTLES OVER THE
SOUTHEAST. FREEZING SPRAY IS LIKELY WEDNESDAY NIGHT AND THURSDAY
DUE TO THE COMBINATION OF STRONG WINDS...LARGE WAVES...AND ARCTIC
AIR OVER THE LAKE.
ALLSOPP
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLOOD WATCH...ILZ003-ILZ004-ILZ008-ILZ010-ILZ011-ILZ019 UNTIL 4
AM WEDNESDAY.
FLOOD WATCH...ILZ005-ILZ006-ILZ012-ILZ013-ILZ014-ILZ020-ILZ021-
ILZ022-ILZ023-ILZ032-ILZ033-ILZ039...6 PM TUESDAY TO 4 AM
WEDNESDAY.
IN...FLOOD WATCH...INZ001-INZ002-INZ010-INZ011-INZ019...6 PM TUESDAY
TO 4 AM WEDNESDAY.
LM...DENSE FOG ADVISORY...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-
LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878
UNTIL 3 AM WEDNESDAY.
GALE WATCH...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...9 AM WEDNESDAY TO 3 AM
THURSDAY.
DENSE FOG ADVISORY...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565
UNTIL 9 PM TUESDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 4 AM WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
149 PM CST TUE JAN 29 2013
.MESOSCALE DISCUSSION...
1110 AM CST
CONTINUE TO MONITOR ENVIRONMENTAL AND RADAR TRENDS WITH AN INCREASE
IN STORM COVERAGE EXPECTED ACROSS THE WESTERN FORECAST AREA FROM 1-3
PM WORKING EASTWARD THROUGH THE LATE AFTERNOON AND NIGHT. CONCERNS
REMAIN FOR ESPECIALLY HEAVY RAIN BUT ALSO FOR POSSIBLE SEVERE STORMS.
SATELLITE CHANNELS AND UPPER AIR PROFILES THIS MORNING SHOW A SHORT
WAVE-LADEN ATMOSPHERIC RIVER ANCHORED FROM THE SOUTHERN PLAIN ACROSS
THE AREA AHEAD OF THE DEEP UPPER TROUGH. A COUPLE IMPULSES
RESPONSIBLE FOR EARLIER MORNING CONVECTION HAVE PASSED INTO MI.
RIGHT NOW THE FORECAST AREA IS IN A BIT OF A LULL THAT LOOKS TO LAST
THROUGH THE NOON HOUR. A COUPLE MORE WAVES...EACH SUCCESSIVE ONE A
LITTLE BETTER DEFINED ON WATER VAPOR...ARE SEEN FROM WESTERN MO
THROUGH CENTRAL OK. AT THE SURFACE...THE COLD FRONT IS NOT FAR
AWAY...INTO SOUTHWEST WI EXTENDING SOUTHWEST INTO WESTERN MO. THE
FRONT HAS AND WILL CONTINUE TO SLOW SOMEWHAT AS A STRONGER SUB
998MB SURFACE LOW DEVELOPS ACROSS OK INTO THE AFTERNOON.
THE ONSET OF OUR CONVECTION IS WHAT LIKELY IS MOVING NORTHEAST OUT
OF MO AHEAD OF ONE OF THE SHORT WAVES. VISIBLE SATELLITE INDICATES
ENHANCED AND ORGANIZED CLOUD TOPS WITH THIS ACTIVITY AND A LOOSE MCS
MAY BE TRYING TO EVOLVE. THIS CONVECTION AS WELL AS MORE DEVELOPING
UNDER IMPROVING UPPER LEVEL FORCING AND LOWER-MID LEVEL CONVERGENCE
SHOULD ENCOMPASS MUCH OF THE WESTERN FORECAST AREA MID TO LATE
AFTERNOON. THINNING ON THE VISIBLE SATELLITE ACROSS THE SOUTHWEST
FORECAST AREA LIKELY WILL ALLOW TEMPS TO REACH THE FORECAST
MID-UPPER 60S. THE RAP FORECAST SOUNDINGS WITH MID 60S INDICATE
SURFACE BASED CAPE OF 500-700 J/KG...INCLUDING ALL IMPORTANT
LOW-LEVEL CAPE IN THESE SITUATIONS NEAR 100 J/KG. MORE THAN ENOUGH
ANALYZED AND FORECAST DEEP LAYER AND LOW-LEVEL SHEAR OF 30-40 KT
WILL SUPPORT ORGANIZED STORMS CAPABLE OF WIND AND ISOLATED
TORNADOES...ESPECIALLY IF THE CAPE VALUES ARE ABLE TO REACH THE
VALUES ABOVE OR HIGHER. THE SPC STORM SCALE ENSEMBLE OF OPPORTUNITY
/SSEO/ DOES INCLUDE A FEW MEMBERS INDICATING HIGHER UPDRAFT HELICITY
IN THIS AREA DURING THE MID TO LATE AFTERNOON...A GENERAL PROXY FOR
ROTATING STORMS.
THIS CONVECTION WILL GRADUALLY EVOLVE EAST LATE THIS AFTERNOON AND
EVENING ALONG WITH REDEVELOPING/ALMOST BACK BUILDING DUE TO STRONG
SUSTAINING MOISTURE TRANSPORT...CONVERGENCE...AND PARALLEL ORIENTED
BULK SHEAR VECTORS TO THE MEAN STORM FLOW. THIS WOULD PUT MUCH OF
THE EASTERN FORECAST AREA UNDER THE BEST CHANCES FOR HEAVY RAIN AND
STRONGER STORMS AFTER 6 PM. HOWEVER...AROUND HALF OF THE EXPLICIT
CONVECTIVE MODELS LOOKED AT DO DEVELOP SCATTERED CONVECTION 3-5 PM
SOUTH OF INTERSTATE 80 NEAR KANKAKEE...GIBSON CITY...AND PONTIAC
AREAS. LOW-LEVEL FLOW IS BACKED MORE HERE SO THIS WOULD BE AN AREA
TO WATCH...BUT CONFIDENCE ON DEVELOPMENT IS LOW AT THIS TIME. DURING
THE EVENING HOWEVER THE SEVERE WEATHER THREAT WILL REMAIN IN THE
EASTERN HALF...ESPECIALLY SOUTH OF INTERSTATE 80 AS LOW-LEVEL SHEAR
AND HELICITY ARE EXTREMELY HIGH. IF TEMPERATURES CAN SUSTAIN
THEMSELVES AND NOT DROP MUCH THIS EVENING IN THOSE AREAS...THE
SURFACE BASED CONVECTIVE THREAT FOR WIND AND ISOLATED TORNADOES
WILL REMAIN. UPSTREAM CONVECTION ACROSS THE MODERATE RISK AREA
COULD STEAL SOME OF THE POTENCY IN OUR CONVECTION BY MID TO LATE
EVE...BUT CERTAINLY NOT THE HEAVY RAIN THREAT.
AND THAT HEAVY RAIN THREAT LOOKS HIGH FOR TONIGHT. PRECIPITABLE
WATERS ARE RUNNING RIGHT AT RECORD HIGHS FOR THE MONTH OF JANUARY
/1.33/ AND ARE FORECAST TO SUSTAIN THEMSELVES TONIGHT WITH AMPLE
REPLENISHMENT. CLASSIC HIGH PWAT AND MOISTURE TRANSPORT AND
CONVERGENCE SIGNATURES POINT TOWARD WIDESPREAD 1-2.50 INCHES OF
RAIN IN TRAINING CONVECTIVE ACTIVITY. THE SSEO INDICATES A SIX
HOUR MEAN OF 1-1.50 INCHES JUST DURING THIS EVENING WHICH IS
IMPRESSIVE FOR A SPREAD OF HIGH RES ENSEMBLES. WILL CONTINUE THE
FLOOD WATCH AS IS.
MTF
&&
.DISCUSSION...
352 AM CST
...RECORD SHATTERING WARMTH LIKELY TODAY WITH HEAVY AND POTENTIALLY
FLOODING RAINS EXPECTED LATER TODAY AND TONIGHT...
THE MOTHER OF ALL WARM FRONTS IS CHARGING NORTH THROUGH THE AREA AT
THIS TIME...WITH TEMPERATURES SOARING RECORD OR NEAR RECORD LEVELS
IN THE MIDDLE OF THE NIGHT BEHIND THIS WARM FRONT. EQUALLY AS
IMPRESSIVE IS THE MOISTURE CONTENT OF THE AIR MASS SPREADING NORTH
INTO THE AREA WITH DEW POINTS CLIMBING INTO THE MID TO UPPER
50S...WHICH IN MANY CASES EXCEED DAILY RECORD HIGH TEMPERATURES.
HIGH TEMP FORECAST FOR TODAY IS TRICKY AS MOST AREAS WILL BE NEAR
60F AT SUNRISE...THOUGH THERE WILL LIKELY BE SCTD SHOWERS AND
THUNDERSTORMS TODAY ALSO EXPECT MANY DRY HOURS WHICH COULD EASILY
ALLOW FOR AT LEAST A 4F+ RISE IN TEMPS WHICH PUTS HIGHS RIVALING ALL
TIME RECORDS FOR THE MONTH OF JANUARY...WITH ANY BREAKS FOR SUNSHINE
ONLY INCREASING THE CHANCE FOR AN ALL TIME RECORD. THE AIR MASS
MOVING IN PRODUCED MID TO UPPER 70S OVER MO AND SW IL MONDAY
AFTERNOON...SO NOT TERRIBLY FAR FETCHED TO FORECAST MID 60S UP HERE
EVEN WITH WIDELY SCTD CONVECTION AROUND.
PRECIPITATION-WISE WIDELY SCATTERED SHOWERS AND THUNDERSTORMS ARE
POSSIBLE AT JUST ABOUT ANY POINT IN TIME TODAY AS SUBTLE AND
INDISTINGUISHABLE DISTURBANCES IN THE SW FLOW COULD KICK OFF
CONVECTION. HOWEVER...WOULD EXPECT MAJORITY OF THE DAY TO BE DRY IN
MOST AREAS UNTIL THE MORE SIGNIFICANT SHORTWAVE APPROACHES WESTERN
CWA LATE THIS AFTERNOON WITH MORE WIDESPREAD AND VIGOROUS
DEVELOPMENT OF SHOWERS AND THUNDERSTORMS UPSTREAM MOVING INTO THE
CWA LATER THIS AFTERNOON. CERTAINLY WITH DEW POINTS NEAR 60F IN
JANUARY AND SEASONABLY EXTREME SHEAR AM RELUCTANT TO DISCOUNT THE
SEVERE WEATHER THREAT...THOUGH THE VERY MOIST ENVIRONMENT SHOULD
FEATURE RATHER MODEST/WEAK LAPSE RATES...SO UNLESS WE GET SOME
SUNSHINE AND BONUS HEATING WOULD GENERALLY THINK THAT INSTABILITY
WILL BE TOO MEAGER FOR THERE TO BE A SIGNIFICANT SEVERE THREAT.
HOWEVER...MUCH LIKE JAN 2008...SHEAR IS EXTREME SO IF WE DO REALIZE
ANY APPRECIABLE INSTABILITY TODAY THEN ALL BETS WOULD BE OFF AND
THERE WOULD BE A DMG WIND AND POSSIBLY EVEN A TORNADO THREAT.
THE SEVERE THREAT LOOKS VERY CONDITIONAL...HOWEVER THE HEAVY RAIN
THREAT LOOKS QUITE HIGH. PRETTY MUCH ANY VARIABLE YOU COULD LOOK AT
TO DIAGNOSE A COLD SEASON HEAVY RAIN THREAT IS NEAR OR EXCEEDING
RECORD LEVELS. PWATS ARE FORECAST TO REACH RECORD LEVELS OVER 1.3
INCHES BY THIS EVENING...WHICH IS OVER 300% OF NORMAL AND COULD EVEN
APPROACH 400% OF NORMAL. LOW/MID LEVEL FLOW WILL BACK AHEAD OF THE
APPROACHING TROUGH AS IT BECOMING MORE NEUTRALLY TILTED...WHICH
SHOULD RESULT IN LONGER RESIDENCE TIME OF THE LARGE BAND OF RAIN AND
CONVECTION IN THE WARM CONVEYOR BELT AS FLOW ALOFT BECOMES MORE
ALIGNED WITH THE LOW LEVEL FRONTAL BOUNDARY. HPC`S STANDARDIZED
ANOMALIES PAGE SHOWS 850MB MOISTURE TRANSPORT VALUES EXCEEDING 6
STANDARD DEVIATIONS ABOVE AVERAGE...OR IN OTHER WORDS NEARLY UNHEARD
OF PROPORTIONS. FEEL THAT WIDESPREAD 1-2" RAINFALL TOTALS ARE LIKELY
WITH 3"+ TOTALS NOT FAR FETCHED...AND WITH DEEP FROZEN GROUND THE
FLOOD POTENTIAL LOOKS HIGH DESPITE BELOW AVG STREAM FLOW HEADING
INTO THE EVENT. HAVE EXPAND THE FFA TO INCLUDE ENTIRE CWA AND
DELAYED START TIME UNTIL TONIGHT FOR CHGO AND NW INDIANA.
MODELS CONTINUE TO TREND SLOWER WITH THE MOVEMENT OF THE WHOLE UPPER
TROUGH WHICH REQUIRED SOME ADJUSTMENTS TO THE GRIDS TO LINGER PRECIP
LATER INTO TONIGHT AND DELAY THE ARRIVAL OF THE COLD AIR AND
SUBSEQUENT CHANGE OVER OF ANY LINGERING PRECIP. THE SLOW MOVING
STRONG COLD FRONT WILL DEMARK THE PATH THAT THE CONGA LINE OF SFC
LOWS WILL TAKE WITH 00Z GUIDANCE A BIT MORE ROBUST WITH THE WAVE
PROGGED TO MOVE UP THE FRONT INTO THE GREAT LAKES TOMORROW. WHILE
STILL A GREAT DEAL OF VARIABILITY...GUIDANCE IS MORE BULLISH WITH
DEVELOPING A DEFORMATION BAND/TROWAL WITH ACCUMULATING SNOW
POTENTIAL TO THE NORTHWEST OF THE LOW TRACK. AT THIS POINT IT WOULD
SEEM THE BEST THREAT OF ACCUMULATING SNOW WOULD BE OVER FAR NW IL
NORTHEAST INTO WI AND MICHIGAN...BUT OUR FAR NW CWA COULD BE CLOSE
ENOUGH FOR A GLANCING BLOW OF ACCUMULATING SNOW. GIVEN LOW
CONFIDENCE HAVE KEPT SNOWFALL AMOUNTS MODEST FOR NOW BUT NUDGE POPS
UP TO LIKELY. MID LEVEL DRY INTRUSION WOULD SEEM TO FAVOR KEEPING
MEASURABLE PRECIP CHANCES LOWER OVER THE MAJORITY OF THE CWA BY THE
TIME TEMPS COOL ENOUGH FOR A CHANGE OVER TO SNOW. THIS IS A VERY
DYNAMIC TROUGH AND FORECAST CONFIDENCE TOMORROW IS LOW SO STAY
TUNED...
PROGRESSIVELY COLDER AIR FILTERS INTO THE REGION WITH FALLING TEMPS
WEDNESDAY AND WEDNESDAY NIGHT. LACK OF SNOW COVER AND LINGERING
CLOUDS/WINDS SHOULD KEEP TEMPS A BIT MORE MODERATE THAN WHAT AN AIR
MASS OF THIS MAGNITUDE WOULD NORMALLY PRODUCE. IT WILL STILL BE A
MAJOR SHOCK TO THE SYSTEM GOING FROM TEMPS NOT FAR FROM 70 TO NEAR 0
OVER NW COUNTIES IN A 48 HOUR PERIOD. CLIPPER STILL LOOKS TO BE IN
THE NEIGHBORHOOD FRIDAY NIGHT INTO SATURDAY AND COULD LAY DOWN A
SWATH OF ACCUMULATING SNOW SOMEWHERE IN THE MIDWEST...BUT FAR TOO
FAR OUT TO PIN POINT A TRACK YET. MODERATING TEMPS ARE EXPECTED
LATER INTO THE WEEKEND INTO NEXT WEEK THOUGH NOTHING LIKE WHAT WE`LL
EXPERIENCE TODAY.
IZZI
&&
.CLIMATE...
330 AM CST
THE FOLLOWING RECORDS COULD BE IN JEOPARDY WITH THE UPCOMING WARM
SPELL TUESDAY...
JANUARY 29 ALL TIME JANUARY
HIGH WARM LOW RECORD HIGH
ROCKFORD 55 (1914) 35 (1989) 63 (1/8/2008, 1/31/1989)
CHICAGO 59 (1914) 38 (1924) 67 (1/25/1950)
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* AN AREA OF SHOWERS AND THUNDERSTORMS APPROACHING ORD AND MDW
FROM THE SOUTHWEST AT 20Z. MORE WIDESPREAD RAIN AND EMBEDDED
THUNDERSTORMS MOVING IN LATER THIS AFTERNOON AND THROUGH THE
EVENING.
* SOUTH TO SOUTHWEST WINDS..GUSTING TO 20-25 KT THROUGH THE
AFTERNOON. WINDS SHIFT TO WEST AND NORTHWEST LATE TONIGHT AS A
COLD FRONT MOVES ACROSS THE AREA.
* MVFR CONDITIONS PREVAILING THIS AFTERNOON AND EVENING. IFR
CONDITIONS TONIGHT.
PAW
//DISCUSSION...UPDATED 18Z...
A SERIES OF UPPER LEVEL WAVES HAS BEEN MOVING ACROSS THE AREA WITH
PERIODS OF SHRA AND TSRA. THE NEXT OF THESE WAVES IS MOVING OUT OF
THE SOUTHERN PLAINS AT MID DAY AND IS EXPECTED TO BRING A LARGE
AREA OF RA/SHRA WITH EMBEDDED TSRA TO NORTHERN IL AND NORTHWEST IN
LATE THIS AFTERNOON AND THROUGH THE EVENING. HAVE HIGHLIGHTED THE
MOST LIKELY TIME FRAME IN THE TAFS BUT THE TIMING MAY NEED TO BE
ADJUSTED AS DETAILS BECOME MORE CLEAR.
CONDITIONS LOWERING TO IFR OVERNIGHT AS A SURFACE COLD FRONT MOVES
ACROSS THE AREA AND SHIFTS THE WINDS TO WEST TO NORTHWEST. COLDER
AIR BEHIND THE FRONT WILL TURN THE REMAINING PRECIPITATION TO SN
ON WEDNESDAY.
PAW
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE IN SHOWER AND THUNDERSTORM TREND. MEDIUM
CONFIDENCE IN TIMING OF MORE WIDESPREAD ACTIVITY LATER THIS
AFTERNOON AND EVENING...AND IN CEILING/VIS DETAILS.
* HIGH CONFIDENCE IN WIND TREND.
* MEDIUM CONFIDENCE IN IFR TIMING.
PAW
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT...VFR.
THURSDAY...VFR.
FRIDAY...CHANCE OF ACCUMULATING SNOW AND MVFR/IFR CONDITIONS AT NIGHT.
SATURDAY...CHANCE OF ACCUMULATING SNOW AND MVFR/IFR CONDITIONS
DURING THE DAY.
SUNDAY...VFR.
MONDAY...VFR.
TRS
&&
.MARINE...
1248 PM CST
SEVERAL WAVES OF LOW PRESSURE WILL RIDE UP A SLOW MOVING COLD
FRONT TONIGHT THROUGH WEDNESDAY AFTERNOON...AS THE FRONT TRAVERSES
LAKE MICHHIGAN. STRONG SOUTH TO SOUTHWEST WINDS AHEAD OF THE
FRONT HAVE PROMPTED A SMALL CRAFT ADVISORY FOR THE IL AND IN
NEARSHORE. WINDS WILL SUBSIDE AS THE FRONT APPROACHES THE ILLINOIS
WATERS LATE THIS AFTERNOON...AND THE INDIANA WATERS THIS EVENING.
AREAS OF DENSE FOG ARE POSSIBLE INTO THIS EVENING...MAINLY OVER
THE SOUTH HALF OF THE LAKE...AS UNSEASONABLY MILD AND HUMID AIR
MOVES OVER THE CHILLY WATER.
BEHIND THE COLD FRONT...NORTHWEST WINDS WILL RAMP UP AS THE FINAL
WAVE OF LOW PRESSURE MOVES INTO EASTERN CANADA AND
INTENSIFIES...WHILE STRONG HIGH PRESSURE BUILDS INTO THE NORTHERN
PLAINS. GALE FORCE WINDS WILL DEVELOP BY MID MORNING WEDNESDAY AND
SLOWLY DIMINISH BELOW GALE FORCE THURSDAY MORNING. THE GALE WATCH
WILL BE UPGRADED TO A GALE WARNING WITH THE 300 PM GLFLM ISSUANCE.
STRONG WEST TO NORTHWEST WINDS WILL CONTINUE THROUGH FRIDAY BEFORE
DIMINISHING THIS WEEKEND AS THE HIGH PRESSURE SETTLES OVER THE
SOUTHEAST. FREEZING SPRAY IS LIKELY WEDNESDAY NIGHT AND THURSDAY
DUE TO THE COMBINATION OF STRONG WINDS...LARGE WAVES...AND ARCTIC
AIR OVER THE LAKE.
ALLSOPP
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLOOD WATCH...ILZ003-ILZ004-ILZ008-ILZ010-ILZ011-ILZ019 UNTIL 4
AM WEDNESDAY.
FLOOD WATCH...ILZ005-ILZ006-ILZ012-ILZ013-ILZ014-ILZ020-ILZ021-
ILZ022-ILZ023-ILZ032-ILZ033-ILZ039...6 PM TUESDAY TO 4 AM
WEDNESDAY.
IN...FLOOD WATCH...INZ001-INZ002-INZ010-INZ011-INZ019...6 PM TUESDAY
TO 4 AM WEDNESDAY.
LM...DENSE FOG ADVISORY...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-
LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878
UNTIL 3 AM WEDNESDAY.
GALE WATCH...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...9 AM WEDNESDAY TO 3 AM
THURSDAY.
DENSE FOG ADVISORY...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565
UNTIL 9 PM TUESDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 4 AM WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
105 PM CST TUE JAN 29 2013
.MESOSCALE DISCUSSION...
1110 AM CST
CONTINUE TO MONITOR ENVIRONMENTAL AND RADAR TRENDS WITH AN INCREASE
IN STORM COVERAGE EXPECTED ACROSS THE WESTERN FORECAST AREA FROM 1-3
PM WORKING EASTWARD THROUGH THE LATE AFTERNOON AND NIGHT. CONCERNS
REMAIN FOR ESPECIALLY HEAVY RAIN BUT ALSO FOR POSSIBLE SEVERE STORMS.
SATELLITE CHANNELS AND UPPER AIR PROFILES THIS MORNING SHOW A SHORT
WAVE-LADEN ATMOSPHERIC RIVER ANCHORED FROM THE SOUTHERN PLAIN ACROSS
THE AREA AHEAD OF THE DEEP UPPER TROUGH. A COUPLE IMPULSES
RESPONSIBLE FOR EARLIER MORNING CONVECTION HAVE PASSED INTO MI.
RIGHT NOW THE FORECAST AREA IS IN A BIT OF A LULL THAT LOOKS TO LAST
THROUGH THE NOON HOUR. A COUPLE MORE WAVES...EACH SUCCESSIVE ONE A
LITTLE BETTER DEFINED ON WATER VAPOR...ARE SEEN FROM WESTERN MO
THROUGH CENTRAL OK. AT THE SURFACE...THE COLD FRONT IS NOT FAR
AWAY...INTO SOUTHWEST WI EXTENDING SOUTHWEST INTO WESTERN MO. THE
FRONT HAS AND WILL CONTINUE TO SLOW SOMEWHAT AS A STRONGER SUB
998MB SURFACE LOW DEVELOPS ACROSS OK INTO THE AFTERNOON.
THE ONSET OF OUR CONVECTION IS WHAT LIKELY IS MOVING NORTHEAST OUT
OF MO AHEAD OF ONE OF THE SHORT WAVES. VISIBLE SATELLITE INDICATES
ENHANCED AND ORGANIZED CLOUD TOPS WITH THIS ACTIVITY AND A LOOSE MCS
MAY BE TRYING TO EVOLVE. THIS CONVECTION AS WELL AS MORE DEVELOPING
UNDER IMPROVING UPPER LEVEL FORCING AND LOWER-MID LEVEL CONVERGENCE
SHOULD ENCOMPASS MUCH OF THE WESTERN FORECAST AREA MID TO LATE
AFTERNOON. THINNING ON THE VISIBLE SATELLITE ACROSS THE SOUTHWEST
FORECAST AREA LIKELY WILL ALLOW TEMPS TO REACH THE FORECAST
MID-UPPER 60S. THE RAP FORECAST SOUNDINGS WITH MID 60S INDICATE
SURFACE BASED CAPE OF 500-700 J/KG...INCLUDING ALL IMPORTANT
LOW-LEVEL CAPE IN THESE SITUATIONS NEAR 100 J/KG. MORE THAN ENOUGH
ANALYZED AND FORECAST DEEP LAYER AND LOW-LEVEL SHEAR OF 30-40 KT
WILL SUPPORT ORGANIZED STORMS CAPABLE OF WIND AND ISOLATED
TORNADOES...ESPECIALLY IF THE CAPE VALUES ARE ABLE TO REACH THE
VALUES ABOVE OR HIGHER. THE SPC STORM SCALE ENSEMBLE OF OPPORTUNITY
/SSEO/ DOES INCLUDE A FEW MEMBERS INDICATING HIGHER UPDRAFT HELICITY
IN THIS AREA DURING THE MID TO LATE AFTERNOON...A GENERAL PROXY FOR
ROTATING STORMS.
THIS CONVECTION WILL GRADUALLY EVOLVE EAST LATE THIS AFTERNOON AND
EVENING ALONG WITH REDEVELOPING/ALMOST BACK BUILDING DUE TO STRONG
SUSTAINING MOISTURE TRANSPORT...CONVERGENCE...AND PARALLEL ORIENTED
BULK SHEAR VECTORS TO THE MEAN STORM FLOW. THIS WOULD PUT MUCH OF
THE EASTERN FORECAST AREA UNDER THE BEST CHANCES FOR HEAVY RAIN AND
STRONGER STORMS AFTER 6 PM. HOWEVER...AROUND HALF OF THE EXPLICIT
CONVECTIVE MODELS LOOKED AT DO DEVELOP SCATTERED CONVECTION 3-5 PM
SOUTH OF INTERSTATE 80 NEAR KANKAKEE...GIBSON CITY...AND PONTIAC
AREAS. LOW-LEVEL FLOW IS BACKED MORE HERE SO THIS WOULD BE AN AREA
TO WATCH...BUT CONFIDENCE ON DEVELOPMENT IS LOW AT THIS TIME. DURING
THE EVENING HOWEVER THE SEVERE WEATHER THREAT WILL REMAIN IN THE
EASTERN HALF...ESPECIALLY SOUTH OF INTERSTATE 80 AS LOW-LEVEL SHEAR
AND HELICITY ARE EXTREMELY HIGH. IF TEMPERATURES CAN SUSTAIN
THEMSELVES AND NOT DROP MUCH THIS EVENING IN THOSE AREAS...THE
SURFACE BASED CONVECTIVE THREAT FOR WIND AND ISOLATED TORNADOES
WILL REMAIN. UPSTREAM CONVECTION ACROSS THE MODERATE RISK AREA
COULD STEAL SOME OF THE POTENCY IN OUR CONVECTION BY MID TO LATE
EVE...BUT CERTAINLY NOT THE HEAVY RAIN THREAT.
AND THAT HEAVY RAIN THREAT LOOKS HIGH FOR TONIGHT. PRECIPITABLE
WATERS ARE RUNNING RIGHT AT RECORD HIGHS FOR THE MONTH OF JANUARY
/1.33/ AND ARE FORECAST TO SUSTAIN THEMSELVES TONIGHT WITH AMPLE
REPLENISHMENT. CLASSIC HIGH PWAT AND MOISTURE TRANSPORT AND
CONVERGENCE SIGNATURES POINT TOWARD WIDESPREAD 1-2.50 INCHES OF
RAIN IN TRAINING CONVECTIVE ACTIVITY. THE SSEO INDICATES A SIX
HOUR MEAN OF 1-1.50 INCHES JUST DURING THIS EVENING WHICH IS
IMPRESSIVE FOR A SPREAD OF HIGH RES ENSEMBLES. WILL CONTINUE THE
FLOOD WATCH AS IS.
MTF
&&
.DISCUSSION...
352 AM CST
...RECORD SHATTERING WARMTH LIKELY TODAY WITH HEAVY AND POTENTIALLY
FLOODING RAINS EXPECTED LATER TODAY AND TONIGHT...
THE MOTHER OF ALL WARM FRONTS IS CHARGING NORTH THROUGH THE AREA AT
THIS TIME...WITH TEMPERATURES SOARING RECORD OR NEAR RECORD LEVELS
IN THE MIDDLE OF THE NIGHT BEHIND THIS WARM FRONT. EQUALLY AS
IMPRESSIVE IS THE MOISTURE CONTENT OF THE AIR MASS SPREADING NORTH
INTO THE AREA WITH DEW POINTS CLIMBING INTO THE MID TO UPPER
50S...WHICH IN MANY CASES EXCEED DAILY RECORD HIGH TEMPERATURES.
HIGH TEMP FORECAST FOR TODAY IS TRICKY AS MOST AREAS WILL BE NEAR
60F AT SUNRISE...THOUGH THERE WILL LIKELY BE SCTD SHOWERS AND
THUNDERSTORMS TODAY ALSO EXPECT MANY DRY HOURS WHICH COULD EASILY
ALLOW FOR AT LEAST A 4F+ RISE IN TEMPS WHICH PUTS HIGHS RIVALING ALL
TIME RECORDS FOR THE MONTH OF JANUARY...WITH ANY BREAKS FOR SUNSHINE
ONLY INCREASING THE CHANCE FOR AN ALL TIME RECORD. THE AIR MASS
MOVING IN PRODUCED MID TO UPPER 70S OVER MO AND SW IL MONDAY
AFTERNOON...SO NOT TERRIBLY FAR FETCHED TO FORECAST MID 60S UP HERE
EVEN WITH WIDELY SCTD CONVECTION AROUND.
PRECIPITATION-WISE WIDELY SCATTERED SHOWERS AND THUNDERSTORMS ARE
POSSIBLE AT JUST ABOUT ANY POINT IN TIME TODAY AS SUBTLE AND
INDISTINGUISHABLE DISTURBANCES IN THE SW FLOW COULD KICK OFF
CONVECTION. HOWEVER...WOULD EXPECT MAJORITY OF THE DAY TO BE DRY IN
MOST AREAS UNTIL THE MORE SIGNIFICANT SHORTWAVE APPROACHES WESTERN
CWA LATE THIS AFTERNOON WITH MORE WIDESPREAD AND VIGOROUS
DEVELOPMENT OF SHOWERS AND THUNDERSTORMS UPSTREAM MOVING INTO THE
CWA LATER THIS AFTERNOON. CERTAINLY WITH DEW POINTS NEAR 60F IN
JANUARY AND SEASONABLY EXTREME SHEAR AM RELUCTANT TO DISCOUNT THE
SEVERE WEATHER THREAT...THOUGH THE VERY MOIST ENVIRONMENT SHOULD
FEATURE RATHER MODEST/WEAK LAPSE RATES...SO UNLESS WE GET SOME
SUNSHINE AND BONUS HEATING WOULD GENERALLY THINK THAT INSTABILITY
WILL BE TOO MEAGER FOR THERE TO BE A SIGNIFICANT SEVERE THREAT.
HOWEVER...MUCH LIKE JAN 2008...SHEAR IS EXTREME SO IF WE DO REALIZE
ANY APPRECIABLE INSTABILITY TODAY THEN ALL BETS WOULD BE OFF AND
THERE WOULD BE A DMG WIND AND POSSIBLY EVEN A TORNADO THREAT.
THE SEVERE THREAT LOOKS VERY CONDITIONAL...HOWEVER THE HEAVY RAIN
THREAT LOOKS QUITE HIGH. PRETTY MUCH ANY VARIABLE YOU COULD LOOK AT
TO DIAGNOSE A COLD SEASON HEAVY RAIN THREAT IS NEAR OR EXCEEDING
RECORD LEVELS. PWATS ARE FORECAST TO REACH RECORD LEVELS OVER 1.3
INCHES BY THIS EVENING...WHICH IS OVER 300% OF NORMAL AND COULD EVEN
APPROACH 400% OF NORMAL. LOW/MID LEVEL FLOW WILL BACK AHEAD OF THE
APPROACHING TROUGH AS IT BECOMING MORE NEUTRALLY TILTED...WHICH
SHOULD RESULT IN LONGER RESIDENCE TIME OF THE LARGE BAND OF RAIN AND
CONVECTION IN THE WARM CONVEYOR BELT AS FLOW ALOFT BECOMES MORE
ALIGNED WITH THE LOW LEVEL FRONTAL BOUNDARY. HPC`S STANDARDIZED
ANOMALIES PAGE SHOWS 850MB MOISTURE TRANSPORT VALUES EXCEEDING 6
STANDARD DEVIATIONS ABOVE AVERAGE...OR IN OTHER WORDS NEARLY UNHEARD
OF PROPORTIONS. FEEL THAT WIDESPREAD 1-2" RAINFALL TOTALS ARE LIKELY
WITH 3"+ TOTALS NOT FAR FETCHED...AND WITH DEEP FROZEN GROUND THE
FLOOD POTENTIAL LOOKS HIGH DESPITE BELOW AVG STREAM FLOW HEADING
INTO THE EVENT. HAVE EXPAND THE FFA TO INCLUDE ENTIRE CWA AND
DELAYED START TIME UNTIL TONIGHT FOR CHGO AND NW INDIANA.
MODELS CONTINUE TO TREND SLOWER WITH THE MOVEMENT OF THE WHOLE UPPER
TROUGH WHICH REQUIRED SOME ADJUSTMENTS TO THE GRIDS TO LINGER PRECIP
LATER INTO TONIGHT AND DELAY THE ARRIVAL OF THE COLD AIR AND
SUBSEQUENT CHANGE OVER OF ANY LINGERING PRECIP. THE SLOW MOVING
STRONG COLD FRONT WILL DEMARK THE PATH THAT THE CONGA LINE OF SFC
LOWS WILL TAKE WITH 00Z GUIDANCE A BIT MORE ROBUST WITH THE WAVE
PROGGED TO MOVE UP THE FRONT INTO THE GREAT LAKES TOMORROW. WHILE
STILL A GREAT DEAL OF VARIABILITY...GUIDANCE IS MORE BULLISH WITH
DEVELOPING A DEFORMATION BAND/TROWAL WITH ACCUMULATING SNOW
POTENTIAL TO THE NORTHWEST OF THE LOW TRACK. AT THIS POINT IT WOULD
SEEM THE BEST THREAT OF ACCUMULATING SNOW WOULD BE OVER FAR NW IL
NORTHEAST INTO WI AND MICHIGAN...BUT OUR FAR NW CWA COULD BE CLOSE
ENOUGH FOR A GLANCING BLOW OF ACCUMULATING SNOW. GIVEN LOW
CONFIDENCE HAVE KEPT SNOWFALL AMOUNTS MODEST FOR NOW BUT NUDGE POPS
UP TO LIKELY. MID LEVEL DRY INTRUSION WOULD SEEM TO FAVOR KEEPING
MEASURABLE PRECIP CHANCES LOWER OVER THE MAJORITY OF THE CWA BY THE
TIME TEMPS COOL ENOUGH FOR A CHANGE OVER TO SNOW. THIS IS A VERY
DYNAMIC TROUGH AND FORECAST CONFIDENCE TOMORROW IS LOW SO STAY
TUNED...
PROGRESSIVELY COLDER AIR FILTERS INTO THE REGION WITH FALLING TEMPS
WEDNESDAY AND WEDNESDAY NIGHT. LACK OF SNOW COVER AND LINGERING
CLOUDS/WINDS SHOULD KEEP TEMPS A BIT MORE MODERATE THAN WHAT AN AIR
MASS OF THIS MAGNITUDE WOULD NORMALLY PRODUCE. IT WILL STILL BE A
MAJOR SHOCK TO THE SYSTEM GOING FROM TEMPS NOT FAR FROM 70 TO NEAR 0
OVER NW COUNTIES IN A 48 HOUR PERIOD. CLIPPER STILL LOOKS TO BE IN
THE NEIGHBORHOOD FRIDAY NIGHT INTO SATURDAY AND COULD LAY DOWN A
SWATH OF ACCUMULATING SNOW SOMEWHERE IN THE MIDWEST...BUT FAR TOO
FAR OUT TO PIN POINT A TRACK YET. MODERATING TEMPS ARE EXPECTED
LATER INTO THE WEEKEND INTO NEXT WEEK THOUGH NOTHING LIKE WHAT WE`LL
EXPERIENCE TODAY.
IZZI
&&
.CLIMATE...
330 AM CST
THE FOLLOWING RECORDS COULD BE IN JEOPARDY WITH THE UPCOMING WARM
SPELL TUESDAY...
JANUARY 29 ALL TIME JANUARY
HIGH WARM LOW RECORD HIGH
ROCKFORD 55 (1914) 35 (1989) 63 (1/8/2008, 1/31/1989)
CHICAGO 59 (1914) 38 (1924) 67 (1/25/1950)
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* A CHANCE OF SHOWERS AND THUNDERSTORMS IN THE AREA THROUGH MID
AFTERNOON. MORE WIDESPREAD RAIN AND SCATTERED THUNDERSTORMS
LATER THIS AFTERNOON THROUGH THE EVENING.
* SOUTH TO SOUTHWEST WINDS..GUSTING TO 20-25 KT THROUGH THE
AFTERNOON. WINDS SHIFT TO WEST AND NORTHWEST LATE TONIGHT AS A
COLD FRONT MOVES ACROSS THE AREA.
* MVFR TO IFR CEILINGS PREVAILING TODAY. IFR CONDITIONS TONIGHT.
PAW
//DISCUSSION...UPDATED 18Z...
A SERIES OF UPPER LEVEL WAVES HAS BEEN MOVING ACROSS THE AREA WITH
PERIODS OF SHRA AND TSRA. THE NEXT OF THESE WAVES IS MOVING OUT OF
THE SOUTHERN PLAINS AT MID DAY AND IS EXPECTED TO BRING A LARGE
AREA OF RA/SHRA WITH EMBEDDED TSRA TO NORTHERN IL AND NORTHWEST IN
LATE THIS AFTERNOON AND THROUGH THE EVENING. HAVE HIGHLIGHTED THE
MOST LIKELY TIME FRAME IN THE TAFS BUT THE TIMING MAY NEED TO BE
ADJUSTED AS DETAILS BECOME MORE CLEAR.
CONDITIONS LOWERING TO IFR OVERNIGHT AS A SURFACE COLD FRONT MOVES
ACROSS THE AREA AND SHIFTS THE WINDS TO WEST TO NORTHWEST. COLDER
AIR BEHIND THE FRONT WILL TURN THE REMAINING PRECIPITATION TO SN
ON WEDNESDAY.
PAW
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH CONFIDENCE IN SHOWER AND THUNDERSTORM TREND. MEDIUM
CONFIDENCE IN TIMING OF MORE WIDESPREAD ACTIVITY LATER THIS
AFTERNOON AND EVENING...AND IN CEILING/VIS DETAILS.
* HIGH CONFIDENCE IN WIND TREND.
* MEDIUM CONFIDENCE IN CEILING TREND.
PAW
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT...VFR.
THURSDAY...VFR.
FRIDAY...CHANCE OF ACCUMULATING SNOW AND MVFR/IFR CONDITIONS AT NIGHT.
SATURDAY...CHANCE OF ACCUMULATING SNOW AND MVFR/IFR CONDITIONS
DURING THE DAY.
SUNDAY...VFR.
MONDAY...VFR.
TRS
&&
.MARINE...
1248 PM CST
SEVERAL WAVES OF LOW PRESSURE WILL RIDE UP A SLOW MOVING COLD
FRONT TONIGHT THROUGH WEDNESDAY AFTERNOON...AS THE FRONT TRAVERSES
LAKE MICHHIGAN. STRONG SOUTH TO SOUTHWEST WINDS AHEAD OF THE
FRONT HAVE PROMPTED A SMALL CRAFT ADVISORY FOR THE IL AND IN
NEARSHORE. WINDS WILL SUBSIDE AS THE FRONT APPROACHES THE ILLINOIS
WATERS LATE THIS AFTERNOON...AND THE INDIANA WATERS THIS EVENING.
AREAS OF DENSE FOG ARE POSSIBLE INTO THIS EVENING...MAINLY OVER
THE SOUTH HALF OF THE LAKE...AS UNSEASONABLY MILD AND HUMID AIR
MOVES OVER THE CHILLY WATER.
BEHIND THE COLD FRONT...NORTHWEST WINDS WILL RAMP UP AS THE FINAL
WAVE OF LOW PRESSURE MOVES INTO EASTERN CANADA AND
INTENSIFIES...WHILE STRONG HIGH PRESSURE BUILDS INTO THE NORTHERN
PLAINS. GALE FORCE WINDS WILL DEVELOP BY MID MORNING WEDNESDAY AND
SLOWLY DIMINISH BELOW GALE FORCE THURSDAY MORNING. THE GALE WATCH
WILL BE UPGRADED TO A GALE WARNING WITH THE 300 PM GLFLM ISSUANCE.
STRONG WEST TO NORTHWEST WINDS WILL CONTINUE THROUGH FRIDAY BEFORE
DIMINISHING THIS WEEKEND AS THE HIGH PRESSURE SETTLES OVER THE
SOUTHEAST. FREEZING SPRAY IS LIKELY WEDNESDAY NIGHT AND THURSDAY
DUE TO THE COMBINATION OF STRONG WINDS...LARGE WAVES...AND ARCTIC
AIR OVER THE LAKE.
ALLSOPP
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLOOD WATCH...ILZ003-ILZ004-ILZ008-ILZ010-ILZ011-ILZ019 UNTIL 4
AM WEDNESDAY.
FLOOD WATCH...ILZ005-ILZ006-ILZ012-ILZ013-ILZ014-ILZ020-ILZ021-
ILZ022-ILZ023-ILZ032-ILZ033-ILZ039...6 PM TUESDAY TO 4 AM
WEDNESDAY.
IN...FLOOD WATCH...INZ001-INZ002-INZ010-INZ011-INZ019...6 PM TUESDAY
TO 4 AM WEDNESDAY.
LM...DENSE FOG ADVISORY...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-
LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878
UNTIL 3 AM WEDNESDAY.
GALE WATCH...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...9 AM WEDNESDAY TO 3 AM
THURSDAY.
DENSE FOG ADVISORY...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565
UNTIL 9 PM TUESDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 4 AM WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1144 AM CST TUE JAN 29 2013
.MESOSCALE DISCUSSION...
1110 AM CST
CONTINUE TO MONITOR ENVIRONMENTAL AND RADAR TRENDS WITH AN INCREASE
IN STORM COVERAGE EXPECTED ACROSS THE WESTERN FORECAST AREA FROM 1-3
PM WORKING EASTWARD THROUGH THE LATE AFTERNOON AND NIGHT. CONCERNS
REMAIN FOR ESPECIALLY HEAVY RAIN BUT ALSO FOR POSSIBLE SEVERE STORMS.
SATELLITE CHANNELS AND UPPER AIR PROFILES THIS MORNING SHOW A SHORT
WAVE-LADEN ATMOSPHERIC RIVER ANCHORED FROM THE SOUTHERN PLAIN ACROSS
THE AREA AHEAD OF THE DEEP UPPER TROUGH. A COUPLE IMPULSES
RESPONSIBLE FOR EARLIER MORNING CONVECTION HAVE PASSED INTO MI.
RIGHT NOW THE FORECAST AREA IS IN A BIT OF A LULL THAT LOOKS TO LAST
THROUGH THE NOON HOUR. A COUPLE MORE WAVES...EACH SUCCESSIVE ONE A
LITTLE BETTER DEFINED ON WATER VAPOR...ARE SEEN FROM WESTERN MO
THROUGH CENTRAL OK. AT THE SURFACE...THE COLD FRONT IS NOT FAR
AWAY...INTO SOUTHWEST WI EXTENDING SOUTHWEST INTO WESTERN MO. THE
FRONT HAS AND WILL CONTINUE TO SLOW SOMEWHAT AS A STRONGER SUB
998MB SURFACE LOW DEVELOPS ACROSS OK INTO THE AFTERNOON.
THE ONSET OF OUR CONVECTION IS WHAT LIKELY IS MOVING NORTHEAST OUT
OF MO AHEAD OF ONE OF THE SHORT WAVES. VISIBLE SATELLITE INDICATES
ENHANCED AND ORGANIZED CLOUD TOPS WITH THIS ACTIVITY AND A LOOSE MCS
MAY BE TRYING TO EVOLVE. THIS CONVECTION AS WELL AS MORE DEVELOPING
UNDER IMPROVING UPPER LEVEL FORCING AND LOWER-MID LEVEL CONVERGENCE
SHOULD ENCOMPASS MUCH OF THE WESTERN FORECAST AREA MID TO LATE
AFTERNOON. THINNING ON THE VISIBLE SATELLITE ACROSS THE SOUTHWEST
FORECAST AREA LIKELY WILL ALLOW TEMPS TO REACH THE FORECAST
MID-UPPER 60S. THE RAP FORECAST SOUNDINGS WITH MID 60S INDICATE
SURFACE BASED CAPE OF 500-700 J/KG...INCLUDING ALL IMPORTANT
LOW-LEVEL CAPE IN THESE SITUATIONS NEAR 100 J/KG. MORE THAN ENOUGH
ANALYZED AND FORECAST DEEP LAYER AND LOW-LEVEL SHEAR OF 30-40 KT
WILL SUPPORT ORGANIZED STORMS CAPABLE OF WIND AND ISOLATED
TORNADOES...ESPECIALLY IF THE CAPE VALUES ARE ABLE TO REACH THE
VALUES ABOVE OR HIGHER. THE SPC STORM SCALE ENSEMBLE OF OPPORTUNITY
/SSEO/ DOES INCLUDE A FEW MEMBERS INDICATING HIGHER UPDRAFT HELICITY
IN THIS AREA DURING THE MID TO LATE AFTERNOON...A GENERAL PROXY FOR
ROTATING STORMS.
THIS CONVECTION WILL GRADUALLY EVOLVE EAST LATE THIS AFTERNOON AND
EVENING ALONG WITH REDEVELOPING/ALMOST BACK BUILDING DUE TO STRONG
SUSTAINING MOISTURE TRANSPORT...CONVERGENCE...AND PARALLEL ORIENTED
BULK SHEAR VECTORS TO THE MEAN STORM FLOW. THIS WOULD PUT MUCH OF
THE EASTERN FORECAST AREA UNDER THE BEST CHANCES FOR HEAVY RAIN AND
STRONGER STORMS AFTER 6 PM. HOWEVER...AROUND HALF OF THE EXPLICIT
CONVECTIVE MODELS LOOKED AT DO DEVELOP SCATTERED CONVECTION 3-5 PM
SOUTH OF INTERSTATE 80 NEAR KANKAKEE...GIBSON CITY...AND PONTIAC
AREAS. LOW-LEVEL FLOW IS BACKED MORE HERE SO THIS WOULD BE AN AREA
TO WATCH...BUT CONFIDENCE ON DEVELOPMENT IS LOW AT THIS TIME. DURING
THE EVENING HOWEVER THE SEVERE WEATHER THREAT WILL REMAIN IN THE
EASTERN HALF...ESPECIALLY SOUTH OF INTERSTATE 80 AS LOW-LEVEL SHEAR
AND HELICITY ARE EXTREMELY HIGH. IF TEMPERATURES CAN SUSTAIN
THEMSELVES AND NOT DROP MUCH THIS EVENING IN THOSE AREAS...THE
SURFACE BASED CONVECTIVE THREAT FOR WIND AND ISOLATED TORNADOES
WILL REMAIN. UPSTREAM CONVECTION ACROSS THE MODERATE RISK AREA
COULD STEAL SOME OF THE POTENCY IN OUR CONVECTION BY MID TO LATE
EVE...BUT CERTAINLY NOT THE HEAVY RAIN THREAT.
AND THAT HEAVY RAIN THREAT LOOKS HIGH FOR TONIGHT. PRECIPITABLE
WATERS ARE RUNNING RIGHT AT RECORD HIGHS FOR THE MONTH OF JANUARY
/1.33/ AND ARE FORECAST TO SUSTAIN THEMSELVES TONIGHT WITH AMPLE
REPLENISHMENT. CLASSIC HIGH PWAT AND MOISTURE TRANSPORT AND
CONVERGENCE SIGNATURES POINT TOWARD WIDESPREAD 1-2.50 INCHES OF
RAIN IN TRAINING CONVECTIVE ACTIVITY. THE SSEO INDICATES A SIX
HOUR MEAN OF 1-1.50 INCHES JUST DURING THIS EVENING WHICH IS
IMPRESSIVE FOR A SPREAD OF HIGH RES ENSEMBLES. WILL CONTINUE THE
FLOOD WATCH AS IS.
MTF
&&
.DISCUSSION...
352 AM CST
...RECORD SHATTERING WARMTH LIKELY TODAY WITH HEAVY AND POTENTIALLY
FLOODING RAINS EXPECTED LATER TODAY AND TONIGHT...
THE MOTHER OF ALL WARM FRONTS IS CHARGING NORTH THROUGH THE AREA AT
THIS TIME...WITH TEMPERATURES SOARING RECORD OR NEAR RECORD LEVELS
IN THE MIDDLE OF THE NIGHT BEHIND THIS WARM FRONT. EQUALLY AS
IMPRESSIVE IS THE MOISTURE CONTENT OF THE AIR MASS SPREADING NORTH
INTO THE AREA WITH DEW POINTS CLIMBING INTO THE MID TO UPPER
50S...WHICH IN MANY CASES EXCEED DAILY RECORD HIGH TEMPERATURES.
HIGH TEMP FORECAST FOR TODAY IS TRICKY AS MOST AREAS WILL BE NEAR
60F AT SUNRISE...THOUGH THERE WILL LIKELY BE SCTD SHOWERS AND
THUNDERSTORMS TODAY ALSO EXPECT MANY DRY HOURS WHICH COULD EASILY
ALLOW FOR AT LEAST A 4F+ RISE IN TEMPS WHICH PUTS HIGHS RIVALING ALL
TIME RECORDS FOR THE MONTH OF JANUARY...WITH ANY BREAKS FOR SUNSHINE
ONLY INCREASING THE CHANCE FOR AN ALL TIME RECORD. THE AIR MASS
MOVING IN PRODUCED MID TO UPPER 70S OVER MO AND SW IL MONDAY
AFTERNOON...SO NOT TERRIBLY FAR FETCHED TO FORECAST MID 60S UP HERE
EVEN WITH WIDELY SCTD CONVECTION AROUND.
PRECIPITATION-WISE WIDELY SCATTERED SHOWERS AND THUNDERSTORMS ARE
POSSIBLE AT JUST ABOUT ANY POINT IN TIME TODAY AS SUBTLE AND
INDISTINGUISHABLE DISTURBANCES IN THE SW FLOW COULD KICK OFF
CONVECTION. HOWEVER...WOULD EXPECT MAJORITY OF THE DAY TO BE DRY IN
MOST AREAS UNTIL THE MORE SIGNIFICANT SHORTWAVE APPROACHES WESTERN
CWA LATE THIS AFTERNOON WITH MORE WIDESPREAD AND VIGOROUS
DEVELOPMENT OF SHOWERS AND THUNDERSTORMS UPSTREAM MOVING INTO THE
CWA LATER THIS AFTERNOON. CERTAINLY WITH DEW POINTS NEAR 60F IN
JANUARY AND SEASONABLY EXTREME SHEAR AM RELUCTANT TO DISCOUNT THE
SEVERE WEATHER THREAT...THOUGH THE VERY MOIST ENVIRONMENT SHOULD
FEATURE RATHER MODEST/WEAK LAPSE RATES...SO UNLESS WE GET SOME
SUNSHINE AND BONUS HEATING WOULD GENERALLY THINK THAT INSTABILITY
WILL BE TOO MEAGER FOR THERE TO BE A SIGNIFICANT SEVERE THREAT.
HOWEVER...MUCH LIKE JAN 2008...SHEAR IS EXTREME SO IF WE DO REALIZE
ANY APPRECIABLE INSTABILITY TODAY THEN ALL BETS WOULD BE OFF AND
THERE WOULD BE A DMG WIND AND POSSIBLY EVEN A TORNADO THREAT.
THE SEVERE THREAT LOOKS VERY CONDITIONAL...HOWEVER THE HEAVY RAIN
THREAT LOOKS QUITE HIGH. PRETTY MUCH ANY VARIABLE YOU COULD LOOK AT
TO DIAGNOSE A COLD SEASON HEAVY RAIN THREAT IS NEAR OR EXCEEDING
RECORD LEVELS. PWATS ARE FORECAST TO REACH RECORD LEVELS OVER 1.3
INCHES BY THIS EVENING...WHICH IS OVER 300% OF NORMAL AND COULD EVEN
APPROACH 400% OF NORMAL. LOW/MID LEVEL FLOW WILL BACK AHEAD OF THE
APPROACHING TROUGH AS IT BECOMING MORE NEUTRALLY TILTED...WHICH
SHOULD RESULT IN LONGER RESIDENCE TIME OF THE LARGE BAND OF RAIN AND
CONVECTION IN THE WARM CONVEYOR BELT AS FLOW ALOFT BECOMES MORE
ALIGNED WITH THE LOW LEVEL FRONTAL BOUNDARY. HPC`S STANDARDIZED
ANOMALIES PAGE SHOWS 850MB MOISTURE TRANSPORT VALUES EXCEEDING 6
STANDARD DEVIATIONS ABOVE AVERAGE...OR IN OTHER WORDS NEARLY UNHEARD
OF PROPORTIONS. FEEL THAT WIDESPREAD 1-2" RAINFALL TOTALS ARE LIKELY
WITH 3"+ TOTALS NOT FAR FETCHED...AND WITH DEEP FROZEN GROUND THE
FLOOD POTENTIAL LOOKS HIGH DESPITE BELOW AVG STREAM FLOW HEADING
INTO THE EVENT. HAVE EXPAND THE FFA TO INCLUDE ENTIRE CWA AND
DELAYED START TIME UNTIL TONIGHT FOR CHGO AND NW INDIANA.
MODELS CONTINUE TO TREND SLOWER WITH THE MOVEMENT OF THE WHOLE UPPER
TROUGH WHICH REQUIRED SOME ADJUSTMENTS TO THE GRIDS TO LINGER PRECIP
LATER INTO TONIGHT AND DELAY THE ARRIVAL OF THE COLD AIR AND
SUBSEQUENT CHANGE OVER OF ANY LINGERING PRECIP. THE SLOW MOVING
STRONG COLD FRONT WILL DEMARK THE PATH THAT THE CONGA LINE OF SFC
LOWS WILL TAKE WITH 00Z GUIDANCE A BIT MORE ROBUST WITH THE WAVE
PROGGED TO MOVE UP THE FRONT INTO THE GREAT LAKES TOMORROW. WHILE
STILL A GREAT DEAL OF VARIABILITY...GUIDANCE IS MORE BULLISH WITH
DEVELOPING A DEFORMATION BAND/TROWAL WITH ACCUMULATING SNOW
POTENTIAL TO THE NORTHWEST OF THE LOW TRACK. AT THIS POINT IT WOULD
SEEM THE BEST THREAT OF ACCUMULATING SNOW WOULD BE OVER FAR NW IL
NORTHEAST INTO WI AND MICHIGAN...BUT OUR FAR NW CWA COULD BE CLOSE
ENOUGH FOR A GLANCING BLOW OF ACCUMULATING SNOW. GIVEN LOW
CONFIDENCE HAVE KEPT SNOWFALL AMOUNTS MODEST FOR NOW BUT NUDGE POPS
UP TO LIKELY. MID LEVEL DRY INTRUSION WOULD SEEM TO FAVOR KEEPING
MEASURABLE PRECIP CHANCES LOWER OVER THE MAJORITY OF THE CWA BY THE
TIME TEMPS COOL ENOUGH FOR A CHANGE OVER TO SNOW. THIS IS A VERY
DYNAMIC TROUGH AND FORECAST CONFIDENCE TOMORROW IS LOW SO STAY
TUNED...
PROGRESSIVELY COLDER AIR FILTERS INTO THE REGION WITH FALLING TEMPS
WEDNESDAY AND WEDNESDAY NIGHT. LACK OF SNOW COVER AND LINGERING
CLOUDS/WINDS SHOULD KEEP TEMPS A BIT MORE MODERATE THAN WHAT AN AIR
MASS OF THIS MAGNITUDE WOULD NORMALLY PRODUCE. IT WILL STILL BE A
MAJOR SHOCK TO THE SYSTEM GOING FROM TEMPS NOT FAR FROM 70 TO NEAR 0
OVER NW COUNTIES IN A 48 HOUR PERIOD. CLIPPER STILL LOOKS TO BE IN
THE NEIGHBORHOOD FRIDAY NIGHT INTO SATURDAY AND COULD LAY DOWN A
SWATH OF ACCUMULATING SNOW SOMEWHERE IN THE MIDWEST...BUT FAR TOO
FAR OUT TO PIN POINT A TRACK YET. MODERATING TEMPS ARE EXPECTED
LATER INTO THE WEEKEND INTO NEXT WEEK THOUGH NOTHING LIKE WHAT WE`LL
EXPERIENCE TODAY.
IZZI
&&
.CLIMATE...
330 AM CST
THE FOLLOWING RECORDS COULD BE IN JEOPARDY WITH THE UPCOMING WARM
SPELL TUESDAY...
JANUARY 29 ALL TIME JANUARY
HIGH WARM LOW RECORD HIGH
ROCKFORD 55 (1914) 35 (1989) 63 (1/8/2008, 1/31/1989)
CHICAGO 59 (1914) 38 (1924) 67 (1/25/1950)
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* A CHANCE OF SHOWERS AND THUNDERSTORMS IN THE AREA THROUGH MID
AFTERNOON. MORE WIDESPREAD RAIN AND SCATTERED THUNDERSTORMS
LATER THIS AFTERNOON THROUGH THE EVENING.
* SOUTH TO SOUTHWEST WINDS..GUSTING TO 20-25 KT THROUGH THE
AFTERNOON. WINDS SHIFT TO WEST AND NORTHWEST LATE TONIGHT AS A
COLD FRONT MOVES ACROSS THE AREA.
* MVFR TO IFR CEILINGS PREVAILING TODAY. IFR CONDITIONS TONIGHT.
PAW
//DISCUSSION...UPDATED 18Z...
A SERIES OF UPPER LEVEL WAVES HAS BEEN MOVING ACROSS THE AREA WITH
PERIODS OF SHRA AND TSRA. THE NEXT OF THESE WAVES IS MOVING OUT OF
THE SOUTHERN PLAINS AT MID DAY AND IS EXPECTED TO BRING A LARGE
AREA OF RA/SHRA WITH EMBEDDED TSRA TO NORTHERN IL AND NORTHWEST IN
LATE THIS AFTERNOON AND THROUGH THE EVENING. HAVE HIGHLIGHTED THE
MOST LIKELY TIME FRAME IN THE TAFS BUT THE TIMING MAY NEED TO BE
ADJUSTED AS DETAILS BECOME MORE CLEAR.
CONDITIONS LOWERING TO IFR OVERNIGHT AS A SURFACE COLD FRONT MOVES
ACROSS THE AREA AND SHIFTS THE WINDS TO WEST TO NORTHWEST. COLDER
AIR BEHIND THE FRONT WILL TURN THE REMAINING PRECIPITATION TO SN
ON WEDNESDAY.
PAW
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH CONFIDENCE IN SHOWER AND THUNDERSTORM TREND. MEDIUM
CONFIDENCE IN TIMING OF MORE WIDESPREAD ACTIVITY LATER THIS
AFTERNOON AND EVENING...AND IN CEILING/VIS DETAILS.
* HIGH CONFIDENCE IN WIND TREND.
* MEDIUM CONFIDENCE IN CEILING TREND.
PAW
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT...VFR.
THURSDAY...VFR.
FRIDAY...CHANCE OF ACCUMULATING SNOW AND MVFR/IFR CONDITIONS AT NIGHT.
SATURDAY...CHANCE OF ACCUMULATING SNOW AND MVFR/IFR CONDITIONS
DURING THE DAY.
SUNDAY...VFR.
MONDAY...VFR.
TRS
&&
.MARINE...
300 AM CST
LOW PRESSURE INCHES OVER IOWA...WILL CONTINUE TO TRACK NORTHEAST
TO SOUTHERN ONTARIO BY THIS EVENING...DRAGGING A WARM FRONT NORTH
ACROSS LAKE MICHIGAN...BRINGING A SURGE OF UNSEASONABLY WARM AND
HUMID AIR TO THE GREAT LAKES. AN ASSOCIATED COLD FRONT TRAILS BACK
TO ANOTHER LOW DEVELOPING OVER THE SOUTH HIGH PLAINS. THIS SECOND
LOW IS EXPECTED TO TRACK NORTHEAST ACROSS THE FAR SOUTHERN TIP OF
THE LAKE LATE TONIGHT WHILE DRAGGING A STRONG COLD FRONT IN IT`S
WAKE. FOLLOWING THE PASSAGE OF THIS SYSTEM...COLD HIGH PRESSURE
WILL BUILD OUT OF CANADA AND SPREAD ACROSS THE UPPER MISSISSIPPI
VALLEY AND WESTERN GREAT LAKES WEDNESDAY AND WEDNESDAY NIGHT. THE
COMBINATION OF THE EXITING LOW...THE BUILDING HIGH AND THE INFLUX
OF MUCH COOLER AIR WILL BRING NORTHWEST GALES TO THE ENTIRE LAKE
BY WEDNESDAY MORNING. GALES SHOULD PERSIST OVER THE LAKE THROUGH
LATE WEDNESDAY NIGHT. THE HIGH PRESSURE WILL THEN SPREAD INTO THE
CENTRAL PLAINS AND MISSOURI VALLEY ON THURSDAY.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLOOD WATCH...ILZ003-ILZ004-ILZ008-ILZ010-ILZ011-ILZ019 UNTIL 4
AM WEDNESDAY.
FLOOD WATCH...ILZ005-ILZ006-ILZ012-ILZ013-ILZ014-ILZ020-ILZ021-
ILZ022-ILZ023-ILZ032-ILZ033-ILZ039...6 PM TUESDAY TO 4 AM
WEDNESDAY.
IN...FLOOD WATCH...INZ001-INZ002-INZ010-INZ011-INZ019...6 PM TUESDAY
TO 4 AM WEDNESDAY.
LM...DENSE FOG ADVISORY...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-
LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878
UNTIL 3 AM WEDNESDAY.
GALE WATCH...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...9 AM WEDNESDAY TO 3 AM
THURSDAY.
DENSE FOG ADVISORY...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565
UNTIL 9 PM TUESDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 4 AM WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS CHICAGO/ROMEOVILLE IL
1112 AM CST TUE JAN 29 2013
.MESOSCALE DISCUSSION...
1110 AM CST
CONTINUE TO MONITOR ENVIRONMENTAL AND RADAR TRENDS WITH AN INCREASE
IN STORM COVERAGE EXPECTED ACROSS THE WESTERN FORECAST AREA FROM 1-3
PM WORKING EASTWARD THROUGH THE LATE AFTERNOON AND NIGHT. CONCERNS
REMAIN FOR ESPECIALLY HEAVY RAIN BUT ALSO FOR POSSIBLE SEVERE STORMS.
SATELLITE CHANNELS AND UPPER AIR PROFILES THIS MORNING SHOW A SHORT
WAVE-LADEN ATMOSPHERIC RIVER ANCHORED FROM THE SOUTHERN PLAIN ACROSS
THE AREA AHEAD OF THE DEEP UPPER TROUGH. A COUPLE IMPULSES
RESPONSIBLE FOR EARLIER MORNING CONVECTION HAVE PASSED INTO MI.
RIGHT NOW THE FORECAST AREA IS IN A BIT OF A LULL THAT LOOKS TO LAST
THROUGH THE NOON HOUR. A COUPLE MORE WAVES...EACH SUCCESSIVE ONE A
LITTLE BETTER DEFINED ON WATER VAPOR...ARE SEEN FROM WESTERN MO
THROUGH CENTRAL OK. AT THE SURFACE...THE COLD FRONT IS NOT FAR
AWAY...INTO SOUTHWEST WI EXTENDING SOUTHWEST INTO WESTERN MO. THE
FRONT HAS AND WILL CONTINUE TO SLOW SOMEWHAT AS A STRONGER SUB
998MB SURFACE LOW DEVELOPS ACROSS OK INTO THE AFTERNOON.
THE ONSET OF OUR CONVECTION IS WHAT LIKELY IS MOVING NORTHEAST OUT
OF MO AHEAD OF ONE OF THE SHORT WAVES. VISIBLE SATELLITE INDICATES
ENHANCED AND ORGANIZED CLOUD TOPS WITH THIS ACTIVITY AND A LOOSE MCS
MAY BE TRYING TO EVOLVE. THIS CONVECTION AS WELL AS MORE DEVELOPING
UNDER IMPROVING UPPER LEVEL FORCING AND LOWER-MID LEVEL CONVERGENCE
SHOULD ENCOMPASS MUCH OF THE WESTERN FORECAST AREA MID TO LATE
AFTERNOON. THINNING ON THE VISIBLE SATELLITE ACROSS THE SOUTHWEST
FORECAST AREA LIKELY WILL ALLOW TEMPS TO REACH THE FORECAST
MID-UPPER 60S. THE RAP FORECAST SOUNDINGS WITH MID 60S INDICATE
SURFACE BASED CAPE OF 500-700 J/KG...INCLUDING ALL IMPORTANT
LOW-LEVEL CAPE IN THESE SITUATIONS NEAR 100 J/KG. MORE THAN ENOUGH
ANALYZED AND FORECAST DEEP LAYER AND LOW-LEVEL SHEAR OF 30-40 KT
WILL SUPPORT ORGANIZED STORMS CAPABLE OF WIND AND ISOLATED
TORNADOES...ESPECIALLY IF THE CAPE VALUES ARE ABLE TO REACH THE
VALUES ABOVE OR HIGHER. THE SPC STORM SCALE ENSEMBLE OF OPPORTUNITY
/SSEO/ DOES INCLUDE A FEW MEMBERS INDICATING HIGHER UPDRAFT HELICITY
IN THIS AREA DURING THE MID TO LATE AFTERNOON...A GENERAL PROXY FOR
ROTATING STORMS.
THIS CONVECTION WILL GRADUALLY EVOLVE EAST LATE THIS AFTERNOON AND
EVENING ALONG WITH REDEVELOPING/ALMOST BACK BUILDING DUE TO STRONG
SUSTAINING MOISTURE TRANSPORT...CONVERGENCE...AND PARALLEL ORIENTED
BULK SHEAR VECTORS TO THE MEAN STORM FLOW. THIS WOULD PUT MUCH OF
THE EASTERN FORECAST AREA UNDER THE BEST CHANCES FOR HEAVY RAIN AND
STRONGER STORMS AFTER 6 PM. HOWEVER...AROUND HALF OF THE EXPLICIT
CONVECTIVE MODELS LOOKED AT DO DEVELOP SCATTERED CONVECTION 3-5 PM
SOUTH OF INTERSTATE 80 NEAR KANKAKEE...GIBSON CITY...AND PONTIAC
AREAS. LOW-LEVEL FLOW IS BACKED MORE HERE SO THIS WOULD BE AN AREA
TO WATCH...BUT CONFIDENCE ON DEVELOPMENT IS LOW AT THIS TIME. DURING
THE EVENING HOWEVER THE SEVERE WEATHER THREAT WILL REMAIN IN THE
EASTERN HALF...ESPECIALLY SOUTH OF INTERSTATE 80 AS LOW-LEVEL SHEAR
AND HELICITY ARE EXTREMELY HIGH. IF TEMPERATURES CAN SUSTAIN
THEMSELVES AND NOT DROP MUCH THIS EVENING IN THOSE AREAS...THE
SURFACE BASED CONVECTIVE THREAT FOR WIND AND ISOLATED TORNADOES
WILL REMAIN. UPSTREAM CONVECTION ACROSS THE MODERATE RISK AREA
COULD STEAL SOME OF THE POTENCY IN OUR CONVECTION BY MID TO LATE
EVE...BUT CERTAINLY NOT THE HEAVY RAIN THREAT.
AND THAT HEAVY RAIN THREAT LOOKS HIGH FOR TONIGHT. PRECIPITABLE
WATERS ARE RUNNING RIGHT AT RECORD HIGHS FOR THE MONTH OF JANUARY
/1.33/ AND ARE FORECAST TO SUSTAIN THEMSELVES TONIGHT WITH AMPLE
REPLENISHMENT. CLASSIC HIGH PWAT AND MOISTURE TRANSPORT AND
CONVERGENCE SIGNATURES POINT TOWARD WIDESPREAD 1-2.50 INCHES OF
RAIN IN TRAINING CONVECTIVE ACTIVITY. THE SSEO INDICATES A SIX
HOUR MEAN OF 1-1.50 INCHES JUST DURING THIS EVENING WHICH IS
IMPRESSIVE FOR A SPREAD OF HIGH RES ENSEMBLES. WILL CONTINUE THE
FLOOD WATCH AS IS.
MTF
&&
.DISCUSSION...
352 AM CST
...RECORD SHATTERING WARMTH LIKELY TODAY WITH HEAVY AND POTENTIALLY
FLOODING RAINS EXPECTED LATER TODAY AND TONIGHT...
THE MOTHER OF ALL WARM FRONTS IS CHARGING NORTH THROUGH THE AREA AT
THIS TIME...WITH TEMPERATURES SOARING RECORD OR NEAR RECORD LEVELS
IN THE MIDDLE OF THE NIGHT BEHIND THIS WARM FRONT. EQUALLY AS
IMPRESSIVE IS THE MOISTURE CONTENT OF THE AIR MASS SPREADING NORTH
INTO THE AREA WITH DEW POINTS CLIMBING INTO THE MID TO UPPER
50S...WHICH IN MANY CASES EXCEED DAILY RECORD HIGH TEMPERATURES.
HIGH TEMP FORECAST FOR TODAY IS TRICKY AS MOST AREAS WILL BE NEAR
60F AT SUNRISE...THOUGH THERE WILL LIKELY BE SCTD SHOWERS AND
THUNDERSTORMS TODAY ALSO EXPECT MANY DRY HOURS WHICH COULD EASILY
ALLOW FOR AT LEAST A 4F+ RISE IN TEMPS WHICH PUTS HIGHS RIVALING ALL
TIME RECORDS FOR THE MONTH OF JANUARY...WITH ANY BREAKS FOR SUNSHINE
ONLY INCREASING THE CHANCE FOR AN ALL TIME RECORD. THE AIR MASS
MOVING IN PRODUCED MID TO UPPER 70S OVER MO AND SW IL MONDAY
AFTERNOON...SO NOT TERRIBLY FAR FETCHED TO FORECAST MID 60S UP HERE
EVEN WITH WIDELY SCTD CONVECTION AROUND.
PRECIPITATION-WISE WIDELY SCATTERED SHOWERS AND THUNDERSTORMS ARE
POSSIBLE AT JUST ABOUT ANY POINT IN TIME TODAY AS SUBTLE AND
INDISTINGUISHABLE DISTURBANCES IN THE SW FLOW COULD KICK OFF
CONVECTION. HOWEVER...WOULD EXPECT MAJORITY OF THE DAY TO BE DRY IN
MOST AREAS UNTIL THE MORE SIGNIFICANT SHORTWAVE APPROACHES WESTERN
CWA LATE THIS AFTERNOON WITH MORE WIDESPREAD AND VIGOROUS
DEVELOPMENT OF SHOWERS AND THUNDERSTORMS UPSTREAM MOVING INTO THE
CWA LATER THIS AFTERNOON. CERTAINLY WITH DEW POINTS NEAR 60F IN
JANUARY AND SEASONABLY EXTREME SHEAR AM RELUCTANT TO DISCOUNT THE
SEVERE WEATHER THREAT...THOUGH THE VERY MOIST ENVIRONMENT SHOULD
FEATURE RATHER MODEST/WEAK LAPSE RATES...SO UNLESS WE GET SOME
SUNSHINE AND BONUS HEATING WOULD GENERALLY THINK THAT INSTABILITY
WILL BE TOO MEAGER FOR THERE TO BE A SIGNIFICANT SEVERE THREAT.
HOWEVER...MUCH LIKE JAN 2008...SHEAR IS EXTREME SO IF WE DO REALIZE
ANY APPRECIABLE INSTABILITY TODAY THEN ALL BETS WOULD BE OFF AND
THERE WOULD BE A DMG WIND AND POSSIBLY EVEN A TORNADO THREAT.
THE SEVERE THREAT LOOKS VERY CONDITIONAL...HOWEVER THE HEAVY RAIN
THREAT LOOKS QUITE HIGH. PRETTY MUCH ANY VARIABLE YOU COULD LOOK AT
TO DIAGNOSE A COLD SEASON HEAVY RAIN THREAT IS NEAR OR EXCEEDING
RECORD LEVELS. PWATS ARE FORECAST TO REACH RECORD LEVELS OVER 1.3
INCHES BY THIS EVENING...WHICH IS OVER 300% OF NORMAL AND COULD EVEN
APPROACH 400% OF NORMAL. LOW/MID LEVEL FLOW WILL BACK AHEAD OF THE
APPROACHING TROUGH AS IT BECOMING MORE NEUTRALLY TILTED...WHICH
SHOULD RESULT IN LONGER RESIDENCE TIME OF THE LARGE BAND OF RAIN AND
CONVECTION IN THE WARM CONVEYOR BELT AS FLOW ALOFT BECOMES MORE
ALIGNED WITH THE LOW LEVEL FRONTAL BOUNDARY. HPC`S STANDARDIZED
ANOMALIES PAGE SHOWS 850MB MOISTURE TRANSPORT VALUES EXCEEDING 6
STANDARD DEVIATIONS ABOVE AVERAGE...OR IN OTHER WORDS NEARLY UNHEARD
OF PROPORTIONS. FEEL THAT WIDESPREAD 1-2" RAINFALL TOTALS ARE LIKELY
WITH 3"+ TOTALS NOT FAR FETCHED...AND WITH DEEP FROZEN GROUND THE
FLOOD POTENTIAL LOOKS HIGH DESPITE BELOW AVG STREAM FLOW HEADING
INTO THE EVENT. HAVE EXPAND THE FFA TO INCLUDE ENTIRE CWA AND
DELAYED START TIME UNTIL TONIGHT FOR CHGO AND NW INDIANA.
MODELS CONTINUE TO TREND SLOWER WITH THE MOVEMENT OF THE WHOLE UPPER
TROUGH WHICH REQUIRED SOME ADJUSTMENTS TO THE GRIDS TO LINGER PRECIP
LATER INTO TONIGHT AND DELAY THE ARRIVAL OF THE COLD AIR AND
SUBSEQUENT CHANGE OVER OF ANY LINGERING PRECIP. THE SLOW MOVING
STRONG COLD FRONT WILL DEMARK THE PATH THAT THE CONGA LINE OF SFC
LOWS WILL TAKE WITH 00Z GUIDANCE A BIT MORE ROBUST WITH THE WAVE
PROGGED TO MOVE UP THE FRONT INTO THE GREAT LAKES TOMORROW. WHILE
STILL A GREAT DEAL OF VARIABILITY...GUIDANCE IS MORE BULLISH WITH
DEVELOPING A DEFORMATION BAND/TROWAL WITH ACCUMULATING SNOW
POTENTIAL TO THE NORTHWEST OF THE LOW TRACK. AT THIS POINT IT WOULD
SEEM THE BEST THREAT OF ACCUMULATING SNOW WOULD BE OVER FAR NW IL
NORTHEAST INTO WI AND MICHIGAN...BUT OUR FAR NW CWA COULD BE CLOSE
ENOUGH FOR A GLANCING BLOW OF ACCUMULATING SNOW. GIVEN LOW
CONFIDENCE HAVE KEPT SNOWFALL AMOUNTS MODEST FOR NOW BUT NUDGE POPS
UP TO LIKELY. MID LEVEL DRY INTRUSION WOULD SEEM TO FAVOR KEEPING
MEASURABLE PRECIP CHANCES LOWER OVER THE MAJORITY OF THE CWA BY THE
TIME TEMPS COOL ENOUGH FOR A CHANGE OVER TO SNOW. THIS IS A VERY
DYNAMIC TROUGH AND FORECAST CONFIDENCE TOMORROW IS LOW SO STAY
TUNED...
PROGRESSIVELY COLDER AIR FILTERS INTO THE REGION WITH FALLING TEMPS
WEDNESDAY AND WEDNESDAY NIGHT. LACK OF SNOW COVER AND LINGERING
CLOUDS/WINDS SHOULD KEEP TEMPS A BIT MORE MODERATE THAN WHAT AN AIR
MASS OF THIS MAGNITUDE WOULD NORMALLY PRODUCE. IT WILL STILL BE A
MAJOR SHOCK TO THE SYSTEM GOING FROM TEMPS NOT FAR FROM 70 TO NEAR 0
OVER NW COUNTIES IN A 48 HOUR PERIOD. CLIPPER STILL LOOKS TO BE IN
THE NEIGHBORHOOD FRIDAY NIGHT INTO SATURDAY AND COULD LAY DOWN A
SWATH OF ACCUMULATING SNOW SOMEWHERE IN THE MIDWEST...BUT FAR TOO
FAR OUT TO PIN POINT A TRACK YET. MODERATING TEMPS ARE EXPECTED
LATER INTO THE WEEKEND INTO NEXT WEEK THOUGH NOTHING LIKE WHAT WE`LL
EXPERIENCE TODAY.
IZZI
&&
.CLIMATE...
330 AM CST
THE FOLLOWING RECORDS COULD BE IN JEOPARDY WITH THE UPCOMING WARM
SPELL TUESDAY...
JANUARY 29 ALL TIME JANUARY
HIGH WARM LOW RECORD HIGH
ROCKFORD 55 (1914) 35 (1989) 63 (1/8/2008, 1/31/1989)
CHICAGO 59 (1914) 38 (1924) 67 (1/25/1950)
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* A CHANCE OF SHOWERS AND THUNDERSTORMS IN THE AREA THROUGH MID
AFTERNOON. MORE WIDESPREAD RAIN AND SCATTERED THUNDERSTORMS
LATER THIS AFTERNOON THROUGH THE EVENING.
* SOUTH TO SOUTHWEST WINDS..GUSTING TO 20-25 KT THROUGH THE
AFTERNOON. WINDS SHIFT TO WEST AND NORTHWEST LATE TONIGHT AS A
COLD FRONT MOVES ACROSS THE AREA.
* MVFR CEILINGS PREVAILING TODAY. IFR CONDITIONS TONIGHT.
PAW
//DISCUSSION...UPDATED 12Z...
ANOTHER SHORT WAVE IS QUICKLY LIFTING NE FROM E CENTRAL IA AND
WILL BE PASSING OVER NW AND N CENTRAL IL AND THEN ON TO S CENTRAL
WI BY 15Z. THIS FEATURE WAS CONTINUING TO DEVELOP AND MAINTAIN
SHOWERS AND THUNDERSTORMS...THAT ARE EXPECTED TO MOVE NE AND OUT
OF NW AND N CENTRAL IL DURING THE EARLY MORNING. ADDITIONAL
SHOWERS AND THUNDERSTORMS ARE EXPECTED AS STRONG SSW-SW FLOW IN
THE LOWER AND MID LEVELS CONTINUES TO RESULT IN ISENTROPIC
UPGLIDE. HOWEVER...THEY ARE EXPECTED TO BE MAINLY ACROSS SE AND E
CENTRAL IA...NW IL AND N CENTRAL IL...AND SW AND S CENTRAL WI AS
THIS IS WHERE THE AXIS OF GREATEST INSTABILITY IS LOCATED.
FORECAST REFLECTIVITY FROM THE 08Z RUN OF THE HRRR HAD A GOOD
DEPICTION OF WHERE MAIN ACTIVITY WAS OCCURRING OVER THE LAST FEW
HOURS. LOOP OF REFLECTIVITY KEEPS THE TERMINALS MAINLY DRY
THROUGH MUCH OF THE DAY WITH A SW-NE BAND OF RAIN AND
THUNDERSTORMS AROUND 75 MILES W THROUGH N OF THE CHICAGO AREA AND
ANOTHER BAND FORM 70 MILES SE TO 150 MILES SW OF ORD AND MDW.
THE WARM FRONT PUSHED N TO THE WI BORDER AT 12Z. THIS RESULTED IN
A WIND SHIFT TO OUT OF THE S-SSW AND A RAPID CLEARING OUT OF THE
FOG THAT BLANKED THE AREA LAST EVENING AND INTO THE LATE
OVERNIGHT HOURS. THE WIDESPREAD LIFR CEILINGS HAVE ALSO IMPROVED
BUT NOT AS QUICKLY AS ARE CURRENTLY MAINLY MVFR. CEILINGS WILL
RISE A BIT MORE TO HIGHER END MVFR BY LATE MORNING. THERE MAY BE
SOME PERIODS OF VFR AS HOLES IN THE STRATOCU MOVE ACROSS THE
AREA.
A MID LEVEL TROUGH CONTINUES TO PROGRESS EASTWARD TODAY WITH ITS
AXIS REACHING A N CENTRAL MN TO TX PANHANDLE LINE BY 00Z...AND A
NE MN TO CENTRAL OK LINE BY 06Z. ANOTHER SHORT WAVE WAS CURRENTLY
LIFTING NE FROM OK AND IS PROGGED TO REACH IA AND MO BY 00Z.
INCREASING LIFT AHEAD OF THE TROUGH AXIS ALONG WITH LOW LEVEL
CONVERGENCE ALONG AND S OF A SLOWLY ADVANCING COLD FRONT AS THE
ASSOCIATED SURFACE LOW RIDES NE ALONG THE BOUNDARY PROGGED TO BE
FROM NORTHERN LAKE MI SW TO LOW PRESSURE IN NE MO BY EVENING WILL
CONTINUE TO SPREAD AN INCREASING AREA OF RAIN AND THUNDERSTORMS
INTO THE LOCAL AREA DURING THE LATER AFTERNOON. THE AREA OF
PRECIPITATION WILL BE SHIFTING NE AND E ACROSS THE LOCAL AREA
DURING THE EARLY TO MID EVENING AS THE SURFACE LOW CONTINUES NE
ALONG THE BOUNDARY TO SOUTHERN LAKE MI PULLING A COLD FRONT
ACROSS NW AND FAR NE IL BY 06Z.
S TO SW WINDS SHOULD CONTINUE TO GUST AT 20-25KT THROUGH THE DAY
THEN DIMINISH THIS EVENING AS THE PRESSURE GRADIENT DECREASES AS
THE FRONT APPROACHES. THE COLD FRONT IS EXPECTED TO PASS ACROSS
THE LOCAL AREA AROUND 07Z WITH A WIND SHIFT TO OUT OF THE W AND
NW. IFR TO LIFR CONDITIONS ARE ANTICIPATED TO RETURN FOR LATER
EVENING AND OVERNIGHT.
TRS
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* HIGH CONFIDENCE IN SHOWER AND THUNDERSTORM TREND. MEDIUM
CONFIDENCE IN TIMING OF MORE WIDESPREAD ACTIVITY LATER THIS
AFTERNOON AND EVENING...AND IN CEILING/VIS DETAILS.
* HIGH CONFIDENCE IN WIND TREND.
* MEDIUM CONFIDENCE IN CEILING TREND.
PAW
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT...VFR.
THURSDAY...VFR.
FRIDAY...CHANCE OF ACCUMULATING SNOW AND MVFR/IFR CONDITIONS AT NIGHT.
SATURDAY...CHANCE OF ACCUMULATING SNOW AND MVFR/IFR CONDITIONS
DURING THE DAY.
SUNDAY...VFR.
MONDAY...VFR.
TRS
&&
.MARINE...
300 AM CST
LOW PRESSURE INCHES OVER IOWA...WILL CONTINUE TO TRACK NORTHEAST
TO SOUTHERN ONTARIO BY THIS EVENING...DRAGGING A WARM FRONT NORTH
ACROSS LAKE MICHIGAN...BRINGING A SURGE OF UNSEASONABLY WARM AND
HUMID AIR TO THE GREAT LAKES. AN ASSOCIATED COLD FRONT TRAILS BACK
TO ANOTHER LOW DEVELOPING OVER THE SOUTH HIGH PLAINS. THIS SECOND
LOW IS EXPECTED TO TRACK NORTHEAST ACROSS THE FAR SOUTHERN TIP OF
THE LAKE LATE TONIGHT WHILE DRAGGING A STRONG COLD FRONT IN IT`S
WAKE. FOLLOWING THE PASSAGE OF THIS SYSTEM...COLD HIGH PRESSURE
WILL BUILD OUT OF CANADA AND SPREAD ACROSS THE UPPER MISSISSIPPI
VALLEY AND WESTERN GREAT LAKES WEDNESDAY AND WEDNESDAY NIGHT. THE
COMBINATION OF THE EXITING LOW...THE BUILDING HIGH AND THE INFLUX
OF MUCH COOLER AIR WILL BRING NORTHWEST GALES TO THE ENTIRE LAKE
BY WEDNESDAY MORNING. GALES SHOULD PERSIST OVER THE LAKE THROUGH
LATE WEDNESDAY NIGHT. THE HIGH PRESSURE WILL THEN SPREAD INTO THE
CENTRAL PLAINS AND MISSOURI VALLEY ON THURSDAY.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLOOD WATCH...ILZ003-ILZ004-ILZ008-ILZ010-ILZ011-ILZ019 UNTIL 4
AM WEDNESDAY.
FLOOD WATCH...ILZ005-ILZ006-ILZ012-ILZ013-ILZ014-ILZ020-ILZ021-
ILZ022-ILZ023-ILZ032-ILZ033-ILZ039...6 PM TUESDAY TO 4 AM
WEDNESDAY.
IN...FLOOD WATCH...INZ001-INZ002-INZ010-INZ011-INZ019...6 PM TUESDAY
TO 4 AM WEDNESDAY.
LM...DENSE FOG ADVISORY...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-
LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878
UNTIL 3 AM WEDNESDAY.
GALE WATCH...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...9 AM WEDNESDAY TO 3 AM
THURSDAY.
DENSE FOG ADVISORY...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565
UNTIL 9 PM TUESDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 4 AM WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1005 AM CST TUE JAN 29 2013
.MESOSCALE DISCUSSION...
538 AM CST
A COUPLE OF LATE THOUGHTS ON THE SEVERE WEATHER POTENTIAL LATER THIS
AFTERNOON.
SUBTLE SHORTWAVE IN THE SOUTHWEST FLOW IS BECOMING A BIT MORE
APPARENT THIS MORNING OVER EASTERN IOWA/NORTHERN MO WITH AN INCREASE
IN SCTD CONVECTION ASSOCIATED WITH THIS FEATURE. AS THIS WAVE MOVES
THROUGH THIS MORNING WOULD ANTICIPATE AN INCREASE IN THE COVERAGE OF
SHOWERS AND STORMS WITH EXTRAPOLATION HAVING THIS WAVE OUT OF OUR
EASTERN CWA BY 15-16Z. IN THE WAKE OF THIS WEAK WAVE COULD SEE A BIT
OF A LULL IN CONVECTION AND MAYBE A THINNING OF CLOUD COVER AND SOME
FILTERED SUNSHINE OR AT LEAST WEAK HEATING.
AS ALLUDED TO IN THE EARLIER AFD...LAPSE RATES ARE WEAK AND NOT
EXPECTED TO IMPROVE MUCH TODAY. WHILE MODELS ARE FORECAST LITTLE TO
NO SURFACE BASED CAPE TODAY...THEY ARE ALSO LIKELY UNDER-DOING
SURFACE TEMPS BY HOLDING READINGS IN THE UPPER 50S ALL AFTERNOON.
ASSUMING FORECAST HIGHS IN THE MID 60S ARE ACHIEVED THEN A FEW
HUNDRED JOULES OF SBCAPE COULD BE REALIZED THIS AFTERNOON AHEAD OF
THE MORE VIGOROUS SHORT WHICH IS EXPECTED TO IGNITE CONVECTION JUST
TO OUR WEST THIS AFTERNOON. ASSUMING WEAK SURFACE BASED INSTABILITY
DOES INDEED MATERIALIZE...THEN LOW AND DEEP LAYER SHEAR WOULD BE
EXCEPTIONALLY SUPPORTIVE OF SEVERE THUNDERSTORMS WITH A WIND DAMAGE
AND POTENTIALLY A LOW END TORNADO THREAT.
THE SEVERE RISK TODAY IS CERTAINLY A VERY CONDITIONAL ONE BASED
LARGELY ON WHETHER SOME WEAK DESTABILIZATION CAN OCCUR AND ALSO THAT
FORCING CAN HELP COMPENSATE FOR THE WEAK INSTABILITY TO ALLOW FOR
UPRIGHT DRAFTS THAT ARE NOT SHEARED APART. WHILE THE SEVERE RISK THIS
AFTERNOON AND EVENING DOES NOT APPEAR HUGE AT THIS TIME...THE
DIFFERENCE BETWEEN NOTHING AND TORNADOES IS ONLY A FEW HUNDRED
JOULES OF CAPE AND THE RIGHT STORM MODE...BOTH OF WHICH ARE VERY
DIFFICULT TO PREDICT BEYOND THE VERY NEAR TERM.
WANTED TO ADD THIS SHORT ADDITION TO THE AFD BECAUSE I FEARED I MAY
HAVE UNINTENTIONALLY DOWNPLAYED THE SEVERE THREAT A BIT TOO MUCH IN
THE INITIAL MORNING AFD.
IZZI
&&
.DISCUSSION...
352 AM CST
...RECORD SHATTERING WARMTH LIKELY TODAY WITH HEAVY AND POTENTIALLY
FLOODING RAINS EXPECTED LATER TODAY AND TONIGHT...
THE MOTHER OF ALL WARM FRONTS IS CHARGING NORTH THROUGH THE AREA AT
THIS TIME...WITH TEMPERATURES SOARING RECORD OR NEAR RECORD LEVELS
IN THE MIDDLE OF THE NIGHT BEHIND THIS WARM FRONT. EQUALLY AS
IMPRESSIVE IS THE MOISTURE CONTENT OF THE AIR MASS SPREADING NORTH
INTO THE AREA WITH DEW POINTS CLIMBING INTO THE MID TO UPPER
50S...WHICH IN MANY CASES EXCEED DAILY RECORD HIGH TEMPERATURES.
HIGH TEMP FORECAST FOR TODAY IS TRICKY AS MOST AREAS WILL BE NEAR
60F AT SUNRISE...THOUGH THERE WILL LIKELY BE SCTD SHOWERS AND
THUNDERSTORMS TODAY ALSO EXPECT MANY DRY HOURS WHICH COULD EASILY
ALLOW FOR AT LEAST A 4F+ RISE IN TEMPS WHICH PUTS HIGHS RIVALING ALL
TIME RECORDS FOR THE MONTH OF JANUARY...WITH ANY BREAKS FOR SUNSHINE
ONLY INCREASING THE CHANCE FOR AN ALL TIME RECORD. THE AIR MASS
MOVING IN PRODUCED MID TO UPPER 70S OVER MO AND SW IL MONDAY
AFTERNOON...SO NOT TERRIBLY FAR FETCHED TO FORECAST MID 60S UP HERE
EVEN WITH WIDELY SCTD CONVECTION AROUND.
PRECIPITATION-WISE WIDELY SCATTERED SHOWERS AND THUNDERSTORMS ARE
POSSIBLE AT JUST ABOUT ANY POINT IN TIME TODAY AS SUBTLE AND
INDISTINGUISHABLE DISTURBANCES IN THE SW FLOW COULD KICK OFF
CONVECTION. HOWEVER...WOULD EXPECT MAJORITY OF THE DAY TO BE DRY IN
MOST AREAS UNTIL THE MORE SIGNIFICANT SHORTWAVE APPROACHES WESTERN
CWA LATE THIS AFTERNOON WITH MORE WIDESPREAD AND VIGOROUS
DEVELOPMENT OF SHOWERS AND THUNDERSTORMS UPSTREAM MOVING INTO THE
CWA LATER THIS AFTERNOON. CERTAINLY WITH DEW POINTS NEAR 60F IN
JANUARY AND SEASONABLY EXTREME SHEAR AM RELUCTANT TO DISCOUNT THE
SEVERE WEATHER THREAT...THOUGH THE VERY MOIST ENVIRONMENT SHOULD
FEATURE RATHER MODEST/WEAK LAPSE RATES...SO UNLESS WE GET SOME
SUNSHINE AND BONUS HEATING WOULD GENERALLY THINK THAT INSTABILITY
WILL BE TOO MEAGER FOR THERE TO BE A SIGNIFICANT SEVERE THREAT.
HOWEVER...MUCH LIKE JAN 2008...SHEAR IS EXTREME SO IF WE DO REALIZE
ANY APPRECIABLE INSTABILITY TODAY THEN ALL BETS WOULD BE OFF AND
THERE WOULD BE A DMG WIND AND POSSIBLY EVEN A TORNADO THREAT.
THE SEVERE THREAT LOOKS VERY CONDITIONAL...HOWEVER THE HEAVY RAIN
THREAT LOOKS QUITE HIGH. PRETTY MUCH ANY VARIABLE YOU COULD LOOK AT
TO DIAGNOSE A COLD SEASON HEAVY RAIN THREAT IS NEAR OR EXCEEDING
RECORD LEVELS. PWATS ARE FORECAST TO REACH RECORD LEVELS OVER 1.3
INCHES BY THIS EVENING...WHICH IS OVER 300% OF NORMAL AND COULD EVEN
APPROACH 400% OF NORMAL. LOW/MID LEVEL FLOW WILL BACK AHEAD OF THE
APPROACHING TROUGH AS IT BECOMING MORE NEUTRALLY TILTED...WHICH
SHOULD RESULT IN LONGER RESIDENCE TIME OF THE LARGE BAND OF RAIN AND
CONVECTION IN THE WARM CONVEYOR BELT AS FLOW ALOFT BECOMES MORE
ALIGNED WITH THE LOW LEVEL FRONTAL BOUNDARY. HPC`S STANDARDIZED
ANOMALIES PAGE SHOWS 850MB MOISTURE TRANSPORT VALUES EXCEEDING 6
STANDARD DEVIATIONS ABOVE AVERAGE...OR IN OTHER WORDS NEARLY UNHEARD
OF PROPORTIONS. FEEL THAT WIDESPREAD 1-2" RAINFALL TOTALS ARE LIKELY
WITH 3"+ TOTALS NOT FAR FETCHED...AND WITH DEEP FROZEN GROUND THE
FLOOD POTENTIAL LOOKS HIGH DESPITE BELOW AVG STREAM FLOW HEADING
INTO THE EVENT. HAVE EXPAND THE FFA TO INCLUDE ENTIRE CWA AND
DELAYED START TIME UNTIL TONIGHT FOR CHGO AND NW INDIANA.
MODELS CONTINUE TO TREND SLOWER WITH THE MOVEMENT OF THE WHOLE UPPER
TROUGH WHICH REQUIRED SOME ADJUSTMENTS TO THE GRIDS TO LINGER PRECIP
LATER INTO TONIGHT AND DELAY THE ARRIVAL OF THE COLD AIR AND
SUBSEQUENT CHANGE OVER OF ANY LINGERING PRECIP. THE SLOW MOVING
STRONG COLD FRONT WILL DEMARK THE PATH THAT THE CONGA LINE OF SFC
LOWS WILL TAKE WITH 00Z GUIDANCE A BIT MORE ROBUST WITH THE WAVE
PROGGED TO MOVE UP THE FRONT INTO THE GREAT LAKES TOMORROW. WHILE
STILL A GREAT DEAL OF VARIABILITY...GUIDANCE IS MORE BULLISH WITH
DEVELOPING A DEFORMATION BAND/TROWAL WITH ACCUMULATING SNOW
POTENTIAL TO THE NORTHWEST OF THE LOW TRACK. AT THIS POINT IT WOULD
SEEM THE BEST THREAT OF ACCUMULATING SNOW WOULD BE OVER FAR NW IL
NORTHEAST INTO WI AND MICHIGAN...BUT OUR FAR NW CWA COULD BE CLOSE
ENOUGH FOR A GLANCING BLOW OF ACCUMULATING SNOW. GIVEN LOW
CONFIDENCE HAVE KEPT SNOWFALL AMOUNTS MODEST FOR NOW BUT NUDGE POPS
UP TO LIKELY. MID LEVEL DRY INTRUSION WOULD SEEM TO FAVOR KEEPING
MEASURABLE PRECIP CHANCES LOWER OVER THE MAJORITY OF THE CWA BY THE
TIME TEMPS COOL ENOUGH FOR A CHANGE OVER TO SNOW. THIS IS A VERY
DYNAMIC TROUGH AND FORECAST CONFIDENCE TOMORROW IS LOW SO STAY
TUNED...
PROGRESSIVELY COLDER AIR FILTERS INTO THE REGION WITH FALLING TEMPS
WEDNESDAY AND WEDNESDAY NIGHT. LACK OF SNOW COVER AND LINGERING
CLOUDS/WINDS SHOULD KEEP TEMPS A BIT MORE MODERATE THAN WHAT AN AIR
MASS OF THIS MAGNITUDE WOULD NORMALLY PRODUCE. IT WILL STILL BE A
MAJOR SHOCK TO THE SYSTEM GOING FROM TEMPS NOT FAR FROM 70 TO NEAR 0
OVER NW COUNTIES IN A 48 HOUR PERIOD. CLIPPER STILL LOOKS TO BE IN
THE NEIGHBORHOOD FRIDAY NIGHT INTO SATURDAY AND COULD LAY DOWN A
SWATH OF ACCUMULATING SNOW SOMEWHERE IN THE MIDWEST...BUT FAR TOO
FAR OUT TO PIN POINT A TRACK YET. MODERATING TEMPS ARE EXPECTED
LATER INTO THE WEEKEND INTO NEXT WEEK THOUGH NOTHING LIKE WHAT WE`LL
EXPERIENCE TODAY.
IZZI
&&
.CLIMATE...
330 AM CST
THE FOLLOWING RECORDS COULD BE IN JEOPARDY WITH THE UPCOMING WARM
SPELL TUESDAY...
JANUARY 29 ALL TIME JANUARY
HIGH WARM LOW RECORD HIGH
ROCKFORD 55 (1914) 35 (1989) 63 (1/8/2008, 1/31/1989)
CHICAGO 59 (1914) 38 (1924) 67 (1/25/1950)
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* A CHANCE OF SHOWERS AND THUNDERSTORMS IN THE AREA THROUGH MID
AFTERNOON. MORE WIDESPREAD RAIN AND SCATTERED THUNDERSTORMS
LATER THIS AFTERNOON THROUGH THE EVENING.
* SOUTH TO SOUTHWEST WINDS..GUSTING TO 20-25 KT THROUGH THE
AFTERNOON. WINDS SHIFT TO WEST AND NORTHWEST LATE TONIGHT AS A
COLD FRONT MOVES ACROSS THE AREA.
* MVFR CEILINGS PREVAILING TODAY. IFR CONDITIONS TONIGHT.
PAW
//DISCUSSION...UPDATED 12Z...
ANOTHER SHORT WAVE IS QUICKLY LIFTING NE FROM E CENTRAL IA AND
WILL BE PASSING OVER NW AND N CENTRAL IL AND THEN ON TO S CENTRAL
WI BY 15Z. THIS FEATURE WAS CONTINUING TO DEVELOP AND MAINTAIN
SHOWERS AND THUNDERSTORMS...THAT ARE EXPECTED TO MOVE NE AND OUT
OF NW AND N CENTRAL IL DURING THE EARLY MORNING. ADDITIONAL
SHOWERS AND THUNDERSTORMS ARE EXPECTED AS STRONG SSW-SW FLOW IN
THE LOWER AND MID LEVELS CONTINUES TO RESULT IN ISENTROPIC
UPGLIDE. HOWEVER...THEY ARE EXPECTED TO BE MAINLY ACROSS SE AND E
CENTRAL IA...NW IL AND N CENTRAL IL...AND SW AND S CENTRAL WI AS
THIS IS WHERE THE AXIS OF GREATEST INSTABILITY IS LOCATED.
FORECAST REFLECTIVITY FROM THE 08Z RUN OF THE HRRR HAD A GOOD
DEPICTION OF WHERE MAIN ACTIVITY WAS OCCURRING OVER THE LAST FEW
HOURS. LOOP OF REFLECTIVITY KEEPS THE TERMINALS MAINLY DRY
THROUGH MUCH OF THE DAY WITH A SW-NE BAND OF RAIN AND
THUNDERSTORMS AROUND 75 MILES W THROUGH N OF THE CHICAGO AREA AND
ANOTHER BAND FORM 70 MILES SE TO 150 MILES SW OF ORD AND MDW.
THE WARM FRONT PUSHED N TO THE WI BORDER AT 12Z. THIS RESULTED IN
A WIND SHIFT TO OUT OF THE S-SSW AND A RAPID CLEARING OUT OF THE
FOG THAT BLANKED THE AREA LAST EVENING AND INTO THE LATE
OVERNIGHT HOURS. THE WIDESPREAD LIFR CEILINGS HAVE ALSO IMPROVED
BUT NOT AS QUICKLY AS ARE CURRENTLY MAINLY MVFR. CEILINGS WILL
RISE A BIT MORE TO HIGHER END MVFR BY LATE MORNING. THERE MAY BE
SOME PERIODS OF VFR AS HOLES IN THE STRATOCU MOVE ACROSS THE
AREA.
A MID LEVEL TROUGH CONTINUES TO PROGRESS EASTWARD TODAY WITH ITS
AXIS REACHING A N CENTRAL MN TO TX PANHANDLE LINE BY 00Z...AND A
NE MN TO CENTRAL OK LINE BY 06Z. ANOTHER SHORT WAVE WAS CURRENTLY
LIFTING NE FROM OK AND IS PROGGED TO REACH IA AND MO BY 00Z.
INCREASING LIFT AHEAD OF THE TROUGH AXIS ALONG WITH LOW LEVEL
CONVERGENCE ALONG AND S OF A SLOWLY ADVANCING COLD FRONT AS THE
ASSOCIATED SURFACE LOW RIDES NE ALONG THE BOUNDARY PROGGED TO BE
FROM NORTHERN LAKE MI SW TO LOW PRESSURE IN NE MO BY EVENING WILL
CONTINUE TO SPREAD AN INCREASING AREA OF RAIN AND THUNDERSTORMS
INTO THE LOCAL AREA DURING THE LATER AFTERNOON. THE AREA OF
PRECIPITATION WILL BE SHIFTING NE AND E ACROSS THE LOCAL AREA
DURING THE EARLY TO MID EVENING AS THE SURFACE LOW CONTINUES NE
ALONG THE BOUNDARY TO SOUTHERN LAKE MI PULLING A COLD FRONT
ACROSS NW AND FAR NE IL BY 06Z.
S TO SW WINDS SHOULD CONTINUE TO GUST AT 20-25KT THROUGH THE DAY
THEN DIMINISH THIS EVENING AS THE PRESSURE GRADIENT DECREASES AS
THE FRONT APPROACHES. THE COLD FRONT IS EXPECTED TO PASS ACROSS
THE LOCAL AREA AROUND 07Z WITH A WIND SHIFT TO OUT OF THE W AND
NW. IFR TO LIFR CONDITIONS ARE ANTICIPATED TO RETURN FOR LATER
EVENING AND OVERNIGHT.
TRS
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* HIGH CONFIDENCE IN SHOWER AND THUNDERSTORM TREND. MEDIUM
CONFIDENCE IN TIMING OF MORE WIDESPREAD ACTIVITY LATER THIS
AFTERNOON AND EVENING...AND IN CEILING/VIS DETAILS.
* HIGH CONFIDENCE IN WIND TREND.
* MEDIUM CONFIDENCE IN CEILING TREND.
PAW
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT...VFR.
THURSDAY...VFR.
FRIDAY...CHANCE OF ACCUMULATING SNOW AND MVFR/IFR CONDITIONS AT NIGHT.
SATURDAY...CHANCE OF ACCUMULATING SNOW AND MVFR/IFR CONDITIONS
DURING THE DAY.
SUNDAY...VFR.
MONDAY...VFR.
TRS
&&
.MARINE...
300 AM CST
LOW PRESSURE INCHES OVER IOWA...WILL CONTINUE TO TRACK NORTHEAST
TO SOUTHERN ONTARIO BY THIS EVENING...DRAGGING A WARM FRONT NORTH
ACROSS LAKE MICHIGAN...BRINGING A SURGE OF UNSEASONABLY WARM AND
HUMID AIR TO THE GREAT LAKES. AN ASSOCIATED COLD FRONT TRAILS BACK
TO ANOTHER LOW DEVELOPING OVER THE SOUTH HIGH PLAINS. THIS SECOND
LOW IS EXPECTED TO TRACK NORTHEAST ACROSS THE FAR SOUTHERN TIP OF
THE LAKE LATE TONIGHT WHILE DRAGGING A STRONG COLD FRONT IN IT`S
WAKE. FOLLOWING THE PASSAGE OF THIS SYSTEM...COLD HIGH PRESSURE
WILL BUILD OUT OF CANADA AND SPREAD ACROSS THE UPPER MISSISSIPPI
VALLEY AND WESTERN GREAT LAKES WEDNESDAY AND WEDNESDAY NIGHT. THE
COMBINATION OF THE EXITING LOW...THE BUILDING HIGH AND THE INFLUX
OF MUCH COOLER AIR WILL BRING NORTHWEST GALES TO THE ENTIRE LAKE
BY WEDNESDAY MORNING. GALES SHOULD PERSIST OVER THE LAKE THROUGH
LATE WEDNESDAY NIGHT. THE HIGH PRESSURE WILL THEN SPREAD INTO THE
CENTRAL PLAINS AND MISSOURI VALLEY ON THURSDAY.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLOOD WATCH...ILZ003-ILZ004-ILZ008-ILZ010-ILZ011-ILZ019 UNTIL 4
AM WEDNESDAY.
FLOOD WATCH...ILZ005-ILZ006-ILZ012-ILZ013-ILZ014-ILZ020-ILZ021-
ILZ022-ILZ023-ILZ032-ILZ033-ILZ039...6 PM TUESDAY TO 4 AM
WEDNESDAY.
IN...FLOOD WATCH...INZ001-INZ002-INZ010-INZ011-INZ019...6 PM TUESDAY
TO 4 AM WEDNESDAY.
LM...DENSE FOG ADVISORY...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-
LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878
UNTIL 3 AM WEDNESDAY.
GALE WATCH...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...9 AM WEDNESDAY TO 3 AM
THURSDAY.
DENSE FOG ADVISORY...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565
UNTIL 9 PM TUESDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 4 AM WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
811 AM CST TUE JAN 29 2013
.MESOSCALE DISCUSSION...
538 AM CST
A COUPLE OF LATE THOUGHTS ON THE SEVERE WEATHER POTENTIAL LATER THIS
AFTERNOON.
SUBTLE SHORTWAVE IN THE SOUTHWEST FLOW IS BECOMING A BIT MORE
APPARENT THIS MORNING OVER EASTERN IOWA/NORTHERN MO WITH AN INCREASE
IN SCTD CONVECTION ASSOCIATED WITH THIS FEATURE. AS THIS WAVE MOVES
THROUGH THIS MORNING WOULD ANTICIPATE AN INCREASE IN THE COVERAGE OF
SHOWERS AND STORMS WITH EXTRAPOLATION HAVING THIS WAVE OUT OF OUR
EASTERN CWA BY 15-16Z. IN THE WAKE OF THIS WEAK WAVE COULD SEE A BIT
OF A LULL IN CONVECTION AND MAYBE A THINNING OF CLOUD COVER AND SOME
FILTERED SUNSHINE OR AT LEAST WEAK HEATING.
AS ALLUDED TO IN THE EARLIER AFD...LAPSE RATES ARE WEAK AND NOT
EXPECTED TO IMPROVE MUCH TODAY. WHILE MODELS ARE FORECAST LITTLE TO
NO SURFACE BASED CAPE TODAY...THEY ARE ALSO LIKELY UNDER-DOING
SURFACE TEMPS BY HOLDING READINGS IN THE UPPER 50S ALL AFTERNOON.
ASSUMING FORECAST HIGHS IN THE MID 60S ARE ACHIEVED THEN A FEW
HUNDRED JOULES OF SBCAPE COULD BE REALIZED THIS AFTERNOON AHEAD OF
THE MORE VIGOROUS SHORT WHICH IS EXPECTED TO IGNITE CONVECTION JUST
TO OUR WEST THIS AFTERNOON. ASSUMING WEAK SURFACE BASED INSTABILITY
DOES INDEED MATERIALIZE...THEN LOW AND DEEP LAYER SHEAR WOULD BE
EXCEPTIONALLY SUPPORTIVE OF SEVERE THUNDERSTORMS WITH A WIND DAMAGE
AND POTENTIALLY A LOW END TORNADO THREAT.
THE SEVERE RISK TODAY IS CERTAINLY A VERY CONDITIONAL ONE BASED
LARGELY ON WHETHER SOME WEAK DESTABILIZATION CAN OCCUR AND ALSO THAT
FORCING CAN HELP COMPENSATE FOR THE WEAK INSTABILITY TO ALLOW FOR
UPRIGHT DRAFTS THAT ARE NOT SHEARED APART. WHILE THE SEVERE RISK THIS
AFTERNOON AND EVENING DOES NOT APPEAR HUGE AT THIS TIME...THE
DIFFERENCE BETWEEN NOTHING AND TORNADOES IS ONLY A FEW HUNDRED
JOULES OF CAPE AND THE RIGHT STORM MODE...BOTH OF WHICH ARE VERY
DIFFICULT TO PREDICT BEYOND THE VERY NEAR TERM.
WANTED TO ADD THIS SHORT ADDITION TO THE AFD BECAUSE I FEARED I MAY
HAVE UNINTENTIONALLY DOWNPLAYED THE SEVERE THREAT A BIT TOO MUCH IN
THE INITIAL MORNING AFD.
IZZI
&&
.DISCUSSION...
352 AM CST
...RECORD SHATTERING WARMTH LIKELY TODAY WITH HEAVY AND POTENTIALLY
FLOODING RAINS EXPECTED LATER TODAY AND TONIGHT...
THE MOTHER OF ALL WARM FRONTS IS CHARGING NORTH THROUGH THE AREA AT
THIS TIME...WITH TEMPERATURES SOARING RECORD OR NEAR RECORD LEVELS
IN THE MIDDLE OF THE NIGHT BEHIND THIS WARM FRONT. EQUALLY AS
IMPRESSIVE IS THE MOISTURE CONTENT OF THE AIR MASS SPREADING NORTH
INTO THE AREA WITH DEW POINTS CLIMBING INTO THE MID TO UPPER
50S...WHICH IN MANY CASES EXCEED DAILY RECORD HIGH TEMPERATURES.
HIGH TEMP FORECAST FOR TODAY IS TRICKY AS MOST AREAS WILL BE NEAR
60F AT SUNRISE...THOUGH THERE WILL LIKELY BE SCTD SHOWERS AND
THUNDERSTORMS TODAY ALSO EXPECT MANY DRY HOURS WHICH COULD EASILY
ALLOW FOR AT LEAST A 4F+ RISE IN TEMPS WHICH PUTS HIGHS RIVALING ALL
TIME RECORDS FOR THE MONTH OF JANUARY...WITH ANY BREAKS FOR SUNSHINE
ONLY INCREASING THE CHANCE FOR AN ALL TIME RECORD. THE AIR MASS
MOVING IN PRODUCED MID TO UPPER 70S OVER MO AND SW IL MONDAY
AFTERNOON...SO NOT TERRIBLY FAR FETCHED TO FORECAST MID 60S UP HERE
EVEN WITH WIDELY SCTD CONVECTION AROUND.
PRECIPITATION-WISE WIDELY SCATTERED SHOWERS AND THUNDERSTORMS ARE
POSSIBLE AT JUST ABOUT ANY POINT IN TIME TODAY AS SUBTLE AND
INDISTINGUISHABLE DISTURBANCES IN THE SW FLOW COULD KICK OFF
CONVECTION. HOWEVER...WOULD EXPECT MAJORITY OF THE DAY TO BE DRY IN
MOST AREAS UNTIL THE MORE SIGNIFICANT SHORTWAVE APPROACHES WESTERN
CWA LATE THIS AFTERNOON WITH MORE WIDESPREAD AND VIGOROUS
DEVELOPMENT OF SHOWERS AND THUNDERSTORMS UPSTREAM MOVING INTO THE
CWA LATER THIS AFTERNOON. CERTAINLY WITH DEW POINTS NEAR 60F IN
JANUARY AND SEASONABLY EXTREME SHEAR AM RELUCTANT TO DISCOUNT THE
SEVERE WEATHER THREAT...THOUGH THE VERY MOIST ENVIRONMENT SHOULD
FEATURE RATHER MODEST/WEAK LAPSE RATES...SO UNLESS WE GET SOME
SUNSHINE AND BONUS HEATING WOULD GENERALLY THINK THAT INSTABILITY
WILL BE TOO MEAGER FOR THERE TO BE A SIGNIFICANT SEVERE THREAT.
HOWEVER...MUCH LIKE JAN 2008...SHEAR IS EXTREME SO IF WE DO REALIZE
ANY APPRECIABLE INSTABILITY TODAY THEN ALL BETS WOULD BE OFF AND
THERE WOULD BE A DMG WIND AND POSSIBLY EVEN A TORNADO THREAT.
THE SEVERE THREAT LOOKS VERY CONDITIONAL...HOWEVER THE HEAVY RAIN
THREAT LOOKS QUITE HIGH. PRETTY MUCH ANY VARIABLE YOU COULD LOOK AT
TO DIAGNOSE A COLD SEASON HEAVY RAIN THREAT IS NEAR OR EXCEEDING
RECORD LEVELS. PWATS ARE FORECAST TO REACH RECORD LEVELS OVER 1.3
INCHES BY THIS EVENING...WHICH IS OVER 300% OF NORMAL AND COULD EVEN
APPROACH 400% OF NORMAL. LOW/MID LEVEL FLOW WILL BACK AHEAD OF THE
APPROACHING TROUGH AS IT BECOMING MORE NEUTRALLY TILTED...WHICH
SHOULD RESULT IN LONGER RESIDENCE TIME OF THE LARGE BAND OF RAIN AND
CONVECTION IN THE WARM CONVEYOR BELT AS FLOW ALOFT BECOMES MORE
ALIGNED WITH THE LOW LEVEL FRONTAL BOUNDARY. HPC`S STANDARDIZED
ANOMALIES PAGE SHOWS 850MB MOISTURE TRANSPORT VALUES EXCEEDING 6
STANDARD DEVIATIONS ABOVE AVERAGE...OR IN OTHER WORDS NEARLY UNHEARD
OF PROPORTIONS. FEEL THAT WIDESPREAD 1-2" RAINFALL TOTALS ARE LIKELY
WITH 3"+ TOTALS NOT FAR FETCHED...AND WITH DEEP FROZEN GROUND THE
FLOOD POTENTIAL LOOKS HIGH DESPITE BELOW AVG STREAM FLOW HEADING
INTO THE EVENT. HAVE EXPAND THE FFA TO INCLUDE ENTIRE CWA AND
DELAYED START TIME UNTIL TONIGHT FOR CHGO AND NW INDIANA.
MODELS CONTINUE TO TREND SLOWER WITH THE MOVEMENT OF THE WHOLE UPPER
TROUGH WHICH REQUIRED SOME ADJUSTMENTS TO THE GRIDS TO LINGER PRECIP
LATER INTO TONIGHT AND DELAY THE ARRIVAL OF THE COLD AIR AND
SUBSEQUENT CHANGE OVER OF ANY LINGERING PRECIP. THE SLOW MOVING
STRONG COLD FRONT WILL DEMARK THE PATH THAT THE CONGA LINE OF SFC
LOWS WILL TAKE WITH 00Z GUIDANCE A BIT MORE ROBUST WITH THE WAVE
PROGGED TO MOVE UP THE FRONT INTO THE GREAT LAKES TOMORROW. WHILE
STILL A GREAT DEAL OF VARIABILITY...GUIDANCE IS MORE BULLISH WITH
DEVELOPING A DEFORMATION BAND/TROWAL WITH ACCUMULATING SNOW
POTENTIAL TO THE NORTHWEST OF THE LOW TRACK. AT THIS POINT IT WOULD
SEEM THE BEST THREAT OF ACCUMULATING SNOW WOULD BE OVER FAR NW IL
NORTHEAST INTO WI AND MICHIGAN...BUT OUR FAR NW CWA COULD BE CLOSE
ENOUGH FOR A GLANCING BLOW OF ACCUMULATING SNOW. GIVEN LOW
CONFIDENCE HAVE KEPT SNOWFALL AMOUNTS MODEST FOR NOW BUT NUDGE POPS
UP TO LIKELY. MID LEVEL DRY INTRUSION WOULD SEEM TO FAVOR KEEPING
MEASURABLE PRECIP CHANCES LOWER OVER THE MAJORITY OF THE CWA BY THE
TIME TEMPS COOL ENOUGH FOR A CHANGE OVER TO SNOW. THIS IS A VERY
DYNAMIC TROUGH AND FORECAST CONFIDENCE TOMORROW IS LOW SO STAY
TUNED...
PROGRESSIVELY COLDER AIR FILTERS INTO THE REGION WITH FALLING TEMPS
WEDNESDAY AND WEDNESDAY NIGHT. LACK OF SNOW COVER AND LINGERING
CLOUDS/WINDS SHOULD KEEP TEMPS A BIT MORE MODERATE THAN WHAT AN AIR
MASS OF THIS MAGNITUDE WOULD NORMALLY PRODUCE. IT WILL STILL BE A
MAJOR SHOCK TO THE SYSTEM GOING FROM TEMPS NOT FAR FROM 70 TO NEAR 0
OVER NW COUNTIES IN A 48 HOUR PERIOD. CLIPPER STILL LOOKS TO BE IN
THE NEIGHBORHOOD FRIDAY NIGHT INTO SATURDAY AND COULD LAY DOWN A
SWATH OF ACCUMULATING SNOW SOMEWHERE IN THE MIDWEST...BUT FAR TOO
FAR OUT TO PIN POINT A TRACK YET. MODERATING TEMPS ARE EXPECTED
LATER INTO THE WEEKEND INTO NEXT WEEK THOUGH NOTHING LIKE WHAT WE`LL
EXPERIENCE TODAY.
IZZI
&&
.CLIMATE...
330 AM CST
THE FOLLOWING RECORDS COULD BE IN JEOPARDY WITH THE UPCOMING WARM
SPELL TUESDAY...
JANUARY 29 ALL TIME JANUARY
HIGH WARM LOW RECORD HIGH
ROCKFORD 55 (1914) 35 (1989) 63 (1/8/2008, 1/31/1989)
CHICAGO 59 (1914) 38 (1924) 67 (1/25/1950)
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* A CHANCE OF SHOWERS AND THUNDERSTORMS IN THE AREA THROUGH MID
AFTERNOON. MORE WIDESPREAD RAIN AND SCATTERED THUNDERSTORMS
LATER THIS AFTERNOON THROUGH THE EVENING.
* SOUTH TO SOUTHWEST WINDS GUSTING TO 20-25 KT DURING THE DAY.
WINDS SHIFT TO WEST AND NORTHWEST LATE TONIGHT AS A COLD FRONT
MOVES ACROSS THE AREA.
* MVFR CEILINGS PREVAILING TODAY. IFR CONDITIONS TONIGHT.
PAW
//DISCUSSION...UPDATED 12Z...
ANOTHER SHORT WAVE IS QUICKLY LIFTING NE FROM E CENTRAL IA AND
WILL BE PASSING OVER NW AND N CENTRAL IL AND THEN ON TO S CENTRAL
WI BY 15Z. THIS FEATURE WAS CONTINUING TO DEVELOP AND MAINTAIN
SHOWERS AND THUNDERSTORMS...THAT ARE EXPECTED TO MOVE NE AND OUT
OF NW AND N CENTRAL IL DURING THE EARLY MORNING. ADDITIONAL
SHOWERS AND THUNDERSTORMS ARE EXPECTED AS STRONG SSW-SW FLOW IN
THE LOWER AND MID LEVELS CONTINUES TO RESULT IN ISENTROPIC
UPGLIDE. HOWEVER...THEY ARE EXPECTED TO BE MAINLY ACROSS SE AND E
CENTRAL IA...NW IL AND N CENTRAL IL...AND SW AND S CENTRAL WI AS
THIS IS WHERE THE AXIS OF GREATEST INSTABILITY IS LOCATED.
FORECAST REFLECTIVITY FROM THE 08Z RUN OF THE HRRR HAD A GOOD
DEPICTION OF WHERE MAIN ACTIVITY WAS OCCURRING OVER THE LAST FEW
HOURS. LOOP OF REFLECTIVITY KEEPS THE TERMINALS MAINLY DRY
THROUGH MUCH OF THE DAY WITH A SW-NE BAND OF RAIN AND
THUNDERSTORMS AROUND 75 MILES W THROUGH N OF THE CHICAGO AREA AND
ANOTHER BAND FORM 70 MILES SE TO 150 MILES SW OF ORD AND MDW.
THE WARM FRONT PUSHED N TO THE WI BORDER AT 12Z. THIS RESULTED IN
A WIND SHIFT TO OUT OF THE S-SSW AND A RAPID CLEARING OUT OF THE
FOG THAT BLANKED THE AREA LAST EVENING AND INTO THE LATE
OVERNIGHT HOURS. THE WIDESPREAD LIFR CEILINGS HAVE ALSO IMPROVED
BUT NOT AS QUICKLY AS ARE CURRENTLY MAINLY MVFR. CEILINGS WILL
RISE A BIT MORE TO HIGHER END MVFR BY LATE MORNING. THERE MAY BE
SOME PERIODS OF VFR AS HOLES IN THE STRATOCU MOVE ACROSS THE
AREA.
A MID LEVEL TROUGH CONTINUES TO PROGRESS EASTWARD TODAY WITH ITS
AXIS REACHING A N CENTRAL MN TO TX PANHANDLE LINE BY 00Z...AND A
NE MN TO CENTRAL OK LINE BY 06Z. ANOTHER SHORT WAVE WAS CURRENTLY
LIFTING NE FROM OK AND IS PROGGED TO REACH IA AND MO BY 00Z.
INCREASING LIFT AHEAD OF THE TROUGH AXIS ALONG WITH LOW LEVEL
CONVERGENCE ALONG AND S OF A SLOWLY ADVANCING COLD FRONT AS THE
ASSOCIATED SURFACE LOW RIDES NE ALONG THE BOUNDARY PROGGED TO BE
FROM NORTHERN LAKE MI SW TO LOW PRESSURE IN NE MO BY EVENING WILL
CONTINUE TO SPREAD AN INCREASING AREA OF RAIN AND THUNDERSTORMS
INTO THE LOCAL AREA DURING THE LATER AFTERNOON. THE AREA OF
PRECIPITATION WILL BE SHIFTING NE AND E ACROSS THE LOCAL AREA
DURING THE EARLY TO MID EVENING AS THE SURFACE LOW CONTINUES NE
ALONG THE BOUNDARY TO SOUTHERN LAKE MI PULLING A COLD FRONT
ACROSS NW AND FAR NE IL BY 06Z.
S TO SW WINDS SHOULD CONTINUE TO GUST AT 20-25KT THROUGH THE DAY
THEN DIMINISH THIS EVENING AS THE PRESSURE GRADIENT DECREASES AS
THE FRONT APPROACHES. THE COLD FRONT IS EXPECTED TO PASS ACROSS
THE LOCAL AREA AROUND 07Z WITH A WIND SHIFT TO OUT OF THE W AND
NW. IFR TO LIFR CONDITIONS ARE ANTICIPATED TO RETURN FOR LATER
EVENING AND OVERNIGHT.
TRS
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* MEDIUM CONFIDENCE THAT SHOWERS AND THUNDERSTORMS WILL NOT BE IN
CLOSE PROXIMITY TO ORD AND MDW UNTIL LATER AFTERNOON.
* HIGH CONFIDENCE IN A PERIOD OF MORE WIDESPREAD SHOWERS AND
THUNDERSTORMS LATER AFTERNOON INTO EVENING. MEDIUM CONFIDENCE IN
TIMING AND CEILING/VIS DETAILS.
* HIGH CONFIDENCE IN WIND TREND.
* MEDIUM CONFIDENCE IN CEILING TREND.
PAW
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT...VFR.
THURSDAY...VFR.
FRIDAY...CHANCE OF ACCUMULATING SNOW AND MVFR/IFR CONDITIONS AT NIGHT.
SATURDAY...CHANCE OF ACCUMULATING SNOW AND MVFR/IFR CONDITIONS
DURING THE DAY.
SUNDAY...VFR.
MONDAY...VFR.
TRS
&&
.MARINE...
300 AM CST
LOW PRESSURE INCHES OVER IOWA...WILL CONTINUE TO TRACK NORTHEAST
TO SOUTHERN ONTARIO BY THIS EVENING...DRAGGING A WARM FRONT NORTH
ACROSS LAKE MICHIGAN...BRINGING A SURGE OF UNSEASONABLY WARM AND
HUMID AIR TO THE GREAT LAKES. AN ASSOCIATED COLD FRONT TRAILS BACK
TO ANOTHER LOW DEVELOPING OVER THE SOUTH HIGH PLAINS. THIS SECOND
LOW IS EXPECTED TO TRACK NORTHEAST ACROSS THE FAR SOUTHERN TIP OF
THE LAKE LATE TONIGHT WHILE DRAGGING A STRONG COLD FRONT IN IT`S
WAKE. FOLLOWING THE PASSAGE OF THIS SYSTEM...COLD HIGH PRESSURE
WILL BUILD OUT OF CANADA AND SPREAD ACROSS THE UPPER MISSISSIPPI
VALLEY AND WESTERN GREAT LAKES WEDNESDAY AND WEDNESDAY NIGHT. THE
COMBINATION OF THE EXITING LOW...THE BUILDING HIGH AND THE INFLUX
OF MUCH COOLER AIR WILL BRING NORTHWEST GALES TO THE ENTIRE LAKE
BY WEDNESDAY MORNING. GALES SHOULD PERSIST OVER THE LAKE THROUGH
LATE WEDNESDAY NIGHT. THE HIGH PRESSURE WILL THEN SPREAD INTO THE
CENTRAL PLAINS AND MISSOURI VALLEY ON THURSDAY.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLOOD WATCH...ILZ003-ILZ004-ILZ008-ILZ010-ILZ011-ILZ019...NOON
TUESDAY TO 4 AM WEDNESDAY.
FLOOD WATCH...ILZ005-ILZ006-ILZ012-ILZ013-ILZ014-ILZ020-ILZ021-
ILZ022-ILZ023-ILZ032-ILZ033-ILZ039...6 PM TUESDAY TO 4 AM
WEDNESDAY.
IN...FLOOD WATCH...INZ001-INZ002-INZ010-INZ011-INZ019...6 PM TUESDAY
TO 4 AM WEDNESDAY.
LM...DENSE FOG ADVISORY...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-
LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878
UNTIL 3 AM WEDNESDAY.
GALE WATCH...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...9 AM WEDNESDAY TO 3 AM
THURSDAY.
DENSE FOG ADVISORY...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565
UNTIL 9 PM TUESDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 4 AM WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
712 AM CST TUE JAN 29 2013
.MESOSCALE DISCUSSION...
538 AM CST
A COUPLE OF LATE THOUGHTS ON THE SEVERE WEATHER POTENTIAL LATER THIS
AFTERNOON.
SUBTLE SHORTWAVE IN THE SOUTHWEST FLOW IS BECOMING A BIT MORE
APPARENT THIS MORNING OVER EASTERN IOWA/NORTHERN MO WITH AN INCREASE
IN SCTD CONVECTION ASSOCIATED WITH THIS FEATURE. AS THIS WAVE MOVES
THROUGH THIS MORNING WOULD ANTICIPATE AN INCREASE IN THE COVERAGE OF
SHOWERS AND STORMS WITH EXTRAPOLATION HAVING THIS WAVE OUT OF OUR
EASTERN CWA BY 15-16Z. IN THE WAKE OF THIS WEAK WAVE COULD SEE A BIT
OF A LULL IN CONVECTION AND MAYBE A THINNING OF CLOUD COVER AND SOME
FILTERED SUNSHINE OR AT LEAST WEAK HEATING.
AS ALLUDED TO IN THE EARLIER AFD...LAPSE RATES ARE WEAK AND NOT
EXPECTED TO IMPROVE MUCH TODAY. WHILE MODELS ARE FORECAST LITTLE TO
NO SURFACE BASED CAPE TODAY...THEY ARE ALSO LIKELY UNDER-DOING
SURFACE TEMPS BY HOLDING READINGS IN THE UPPER 50S ALL AFTERNOON.
ASSUMING FORECAST HIGHS IN THE MID 60S ARE ACHIEVED THEN A FEW
HUNDRED JOULES OF SBCAPE COULD BE REALIZED THIS AFTERNOON AHEAD OF
THE MORE VIGOROUS SHORT WHICH IS EXPECTED TO IGNITE CONVECTION JUST
TO OUR WEST THIS AFTERNOON. ASSUMING WEAK SURFACE BASED INSTABILITY
DOES INDEED MATERIALIZE...THEN LOW AND DEEP LAYER SHEAR WOULD BE
EXCEPTIONALLY SUPPORTIVE OF SEVERE THUNDERSTORMS WITH A WIND DAMAGE
AND POTENTIALLY A LOW END TORNADO THREAT.
THE SEVERE RISK TODAY IS CERTAINLY A VERY CONDITIONAL ONE BASED
LARGELY ON WHETHER SOME WEAK DESTABILIZATION CAN OCCUR AND ALSO THAT
FORCING CAN HELP COMPENSATE FOR THE WEAK INSTABILITY TO ALLOW FOR
UPRIGHT DRAFTS THAT ARE NOT SHEARED APART. WHILE THE SEVERE RISK THIS
AFTERNOON AND EVENING DOES NOT APPEAR HUGE AT THIS TIME...THE
DIFFERENCE BETWEEN NOTHING AND TORNADOES IS ONLY A FEW HUNDRED
JOULES OF CAPE AND THE RIGHT STORM MODE...BOTH OF WHICH ARE VERY
DIFFICULT TO PREDICT BEYOND THE VERY NEAR TERM.
WANTED TO ADD THIS SHORT ADDITION TO THE AFD BECAUSE I FEARED I MAY
HAVE UNINTENTIONALLY DOWNPLAYED THE SEVERE THREAT A BIT TOO MUCH IN
THE INITIAL MORNING AFD.
IZZI
&&
.DISCUSSION...
352 AM CST
...RECORD SHATTERING WARMTH LIKELY TODAY WITH HEAVY AND POTENTIALLY
FLOODING RAINS EXPECTED LATER TODAY AND TONIGHT...
THE MOTHER OF ALL WARM FRONTS IS CHARGING NORTH THROUGH THE AREA AT
THIS TIME...WITH TEMPERATURES SOARING RECORD OR NEAR RECORD LEVELS
IN THE MIDDLE OF THE NIGHT BEHIND THIS WARM FRONT. EQUALLY AS
IMPRESSIVE IS THE MOISTURE CONTENT OF THE AIR MASS SPREADING NORTH
INTO THE AREA WITH DEW POINTS CLIMBING INTO THE MID TO UPPER
50S...WHICH IN MANY CASES EXCEED DAILY RECORD HIGH TEMPERATURES.
HIGH TEMP FORECAST FOR TODAY IS TRICKY AS MOST AREAS WILL BE NEAR
60F AT SUNRISE...THOUGH THERE WILL LIKELY BE SCTD SHOWERS AND
THUNDERSTORMS TODAY ALSO EXPECT MANY DRY HOURS WHICH COULD EASILY
ALLOW FOR AT LEAST A 4F+ RISE IN TEMPS WHICH PUTS HIGHS RIVALING ALL
TIME RECORDS FOR THE MONTH OF JANUARY...WITH ANY BREAKS FOR SUNSHINE
ONLY INCREASING THE CHANCE FOR AN ALL TIME RECORD. THE AIR MASS
MOVING IN PRODUCED MID TO UPPER 70S OVER MO AND SW IL MONDAY
AFTERNOON...SO NOT TERRIBLY FAR FETCHED TO FORECAST MID 60S UP HERE
EVEN WITH WIDELY SCTD CONVECTION AROUND.
PRECIPITATION-WISE WIDELY SCATTERED SHOWERS AND THUNDERSTORMS ARE
POSSIBLE AT JUST ABOUT ANY POINT IN TIME TODAY AS SUBTLE AND
INDISTINGUISHABLE DISTURBANCES IN THE SW FLOW COULD KICK OFF
CONVECTION. HOWEVER...WOULD EXPECT MAJORITY OF THE DAY TO BE DRY IN
MOST AREAS UNTIL THE MORE SIGNIFICANT SHORTWAVE APPROACHES WESTERN
CWA LATE THIS AFTERNOON WITH MORE WIDESPREAD AND VIGOROUS
DEVELOPMENT OF SHOWERS AND THUNDERSTORMS UPSTREAM MOVING INTO THE
CWA LATER THIS AFTERNOON. CERTAINLY WITH DEW POINTS NEAR 60F IN
JANUARY AND SEASONABLY EXTREME SHEAR AM RELUCTANT TO DISCOUNT THE
SEVERE WEATHER THREAT...THOUGH THE VERY MOIST ENVIRONMENT SHOULD
FEATURE RATHER MODEST/WEAK LAPSE RATES...SO UNLESS WE GET SOME
SUNSHINE AND BONUS HEATING WOULD GENERALLY THINK THAT INSTABILITY
WILL BE TOO MEAGER FOR THERE TO BE A SIGNIFICANT SEVERE THREAT.
HOWEVER...MUCH LIKE JAN 2008...SHEAR IS EXTREME SO IF WE DO REALIZE
ANY APPRECIABLE INSTABILITY TODAY THEN ALL BETS WOULD BE OFF AND
THERE WOULD BE A DMG WIND AND POSSIBLY EVEN A TORNADO THREAT.
THE SEVERE THREAT LOOKS VERY CONDITIONAL...HOWEVER THE HEAVY RAIN
THREAT LOOKS QUITE HIGH. PRETTY MUCH ANY VARIABLE YOU COULD LOOK AT
TO DIAGNOSE A COLD SEASON HEAVY RAIN THREAT IS NEAR OR EXCEEDING
RECORD LEVELS. PWATS ARE FORECAST TO REACH RECORD LEVELS OVER 1.3
INCHES BY THIS EVENING...WHICH IS OVER 300% OF NORMAL AND COULD EVEN
APPROACH 400% OF NORMAL. LOW/MID LEVEL FLOW WILL BACK AHEAD OF THE
APPROACHING TROUGH AS IT BECOMING MORE NEUTRALLY TILTED...WHICH
SHOULD RESULT IN LONGER RESIDENCE TIME OF THE LARGE BAND OF RAIN AND
CONVECTION IN THE WARM CONVEYOR BELT AS FLOW ALOFT BECOMES MORE
ALIGNED WITH THE LOW LEVEL FRONTAL BOUNDARY. HPC`S STANDARDIZED
ANOMALIES PAGE SHOWS 850MB MOISTURE TRANSPORT VALUES EXCEEDING 6
STANDARD DEVIATIONS ABOVE AVERAGE...OR IN OTHER WORDS NEARLY UNHEARD
OF PROPORTIONS. FEEL THAT WIDESPREAD 1-2" RAINFALL TOTALS ARE LIKELY
WITH 3"+ TOTALS NOT FAR FETCHED...AND WITH DEEP FROZEN GROUND THE
FLOOD POTENTIAL LOOKS HIGH DESPITE BELOW AVG STREAM FLOW HEADING
INTO THE EVENT. HAVE EXPAND THE FFA TO INCLUDE ENTIRE CWA AND
DELAYED START TIME UNTIL TONIGHT FOR CHGO AND NW INDIANA.
MODELS CONTINUE TO TREND SLOWER WITH THE MOVEMENT OF THE WHOLE UPPER
TROUGH WHICH REQUIRED SOME ADJUSTMENTS TO THE GRIDS TO LINGER PRECIP
LATER INTO TONIGHT AND DELAY THE ARRIVAL OF THE COLD AIR AND
SUBSEQUENT CHANGE OVER OF ANY LINGERING PRECIP. THE SLOW MOVING
STRONG COLD FRONT WILL DEMARK THE PATH THAT THE CONGA LINE OF SFC
LOWS WILL TAKE WITH 00Z GUIDANCE A BIT MORE ROBUST WITH THE WAVE
PROGGED TO MOVE UP THE FRONT INTO THE GREAT LAKES TOMORROW. WHILE
STILL A GREAT DEAL OF VARIABILITY...GUIDANCE IS MORE BULLISH WITH
DEVELOPING A DEFORMATION BAND/TROWAL WITH ACCUMULATING SNOW
POTENTIAL TO THE NORTHWEST OF THE LOW TRACK. AT THIS POINT IT WOULD
SEEM THE BEST THREAT OF ACCUMULATING SNOW WOULD BE OVER FAR NW IL
NORTHEAST INTO WI AND MICHIGAN...BUT OUR FAR NW CWA COULD BE CLOSE
ENOUGH FOR A GLANCING BLOW OF ACCUMULATING SNOW. GIVEN LOW
CONFIDENCE HAVE KEPT SNOWFALL AMOUNTS MODEST FOR NOW BUT NUDGE POPS
UP TO LIKELY. MID LEVEL DRY INTRUSION WOULD SEEM TO FAVOR KEEPING
MEASURABLE PRECIP CHANCES LOWER OVER THE MAJORITY OF THE CWA BY THE
TIME TEMPS COOL ENOUGH FOR A CHANGE OVER TO SNOW. THIS IS A VERY
DYNAMIC TROUGH AND FORECAST CONFIDENCE TOMORROW IS LOW SO STAY
TUNED...
PROGRESSIVELY COLDER AIR FILTERS INTO THE REGION WITH FALLING TEMPS
WEDNESDAY AND WEDNESDAY NIGHT. LACK OF SNOW COVER AND LINGERING
CLOUDS/WINDS SHOULD KEEP TEMPS A BIT MORE MODERATE THAN WHAT AN AIR
MASS OF THIS MAGNITUDE WOULD NORMALLY PRODUCE. IT WILL STILL BE A
MAJOR SHOCK TO THE SYSTEM GOING FROM TEMPS NOT FAR FROM 70 TO NEAR 0
OVER NW COUNTIES IN A 48 HOUR PERIOD. CLIPPER STILL LOOKS TO BE IN
THE NEIGHBORHOOD FRIDAY NIGHT INTO SATURDAY AND COULD LAY DOWN A
SWATH OF ACCUMULATING SNOW SOMEWHERE IN THE MIDWEST...BUT FAR TOO
FAR OUT TO PIN POINT A TRACK YET. MODERATING TEMPS ARE EXPECTED
LATER INTO THE WEEKEND INTO NEXT WEEK THOUGH NOTHING LIKE WHAT WE`LL
EXPERIENCE TODAY.
IZZI
&&
.CLIMATE...
330 AM CST
THE FOLLOWING RECORDS COULD BE IN JEOPARDY WITH THE UPCOMING WARM
SPELL TUESDAY...
JANUARY 29 ALL TIME JANUARY
HIGH WARM LOW RECORD HIGH
ROCKFORD 55 (1914) 35 (1989) 63 (1/8/2008, 1/31/1989)
CHICAGO 59 (1914) 38 (1924) 67 (1/25/1950)
IZZI
&&
.AVIATION...
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 12Z...
* MVFR CEILINGS TODAY.
* A CHANCE OF SHOWERS AND THUNDERSTORMS THOUGH MID AFTERNOON.
* WIDESPREAD RAIN AND SCATTERED THUNDERSTORMS LATER AFTERNOON
THROUGH EVENING.
* SOUTH TO SOUTHWEST WINDS GUST UP TO 25KT DURING THE DAY.
* WINDS SHIFT TO WEST AND NORTHWEST LATE TONIGHT AS A COLD FRONT
MOVES EAST ACROSS THE AREA.
* RETURN OF LIFR CONDITIONS TONIGHT...MAINLY DUE TO LOW CEILINGS.
TRS
//DISCUSSION...UPDATED 12Z
ANOTHER SHORT WAVE IS QUICKLY LIFTING NE FROM E CENTRAL IA AND
WILL BE PASSING OVER NW AND N CENTRAL IL AND THEN ON TO S CENTRAL
WI BY 15Z. THIS FEATURE WAS CONTINUING TO DEVELOP AND MAINTAIN
SHOWERS AND THUNDERSTORMS...THAT ARE EXPECTED TO MOVE NE AND OUT
OF NW AND N CENTRAL IL DURING THE EARLY MORNING. ADDITIONAL
SHOWERS AND THUNDERSTORMS ARE EXPECTED AS STRONG SSW-SW FLOW IN
THE LOWER AND MID LEVELS CONTINUES TO RESULT IN ISENTROPIC
UPGLIDE. HOWEVER...THEY ARE EXPECTED TO BE MAINLY ACROSS SE AND E
CENTRAL IA...NW IL AND N CENTRAL IL...AND SW AND S CENTRAL WI AS
THIS IS WHERE THE AXIS OF GREATEST INSTABILITY IS LOCATED.
FORECAST REFLECTIVITY FROM THE 08Z RUN OF THE HRRR HAD A GOOD
DEPICTION OF WHERE MAIN ACTIVITY WAS OCCURRING OVER THE LAST FEW
HOURS. LOOP OF REFLECTIVITY KEEPS THE TERMINALS MAINLY DRY
THROUGH MUCH OF THE DAY WITH A SW-NE BAND OF RAIN AND
THUNDERSTORMS AROUND 75 MILES W THROUGH N OF THE CHICAGO AREA AND
ANOTHER BAND FORM 70 MILES SE TO 150 MILES SW OF ORD AND MDW.
THE WARM FRONT PUSHED N TO THE WI BORDER AT 12Z. THIS RESULTED IN
A WIND SHIFT TO OUT OF THE S-SSW AND A RAPID CLEARING OUT OF THE
FOG THAT BLANKED THE AREA LAST EVENING AND INTO THE LATE
OVERNIGHT HOURS. THE WIDESPREAD LIFR CEILINGS HAVE ALSO IMPROVED
BUT NOT AS QUICKLY AS ARE CURRENTLY MAINLY MVFR. CEILINGS WILL
RISE A BIT MORE TO HIGHER END MVFR BY LATE MORNING. THERE MAY BE
SOME PERIODS OF VFR AS HOLES IN THE STRATOCU MOVE ACROSS THE
AREA.
A MID LEVEL TROUGH CONTINUES TO PROGRESS EASTWARD TODAY WITH ITS
AXIS REACHING A N CENTRAL MN TO TX PANHANDLE LINE BY 00Z...AND A
NE MN TO CENTRAL OK LINE BY 06Z. ANOTHER SHORT WAVE WAS CURRENTLY
LIFTING NE FROM OK AND IS PROGGED TO REACH IA AND MO BY 00Z.
INCREASING LIFT AHEAD OF THE TROUGH AXIS ALONG WITH LOW LEVEL
CONVERGENCE ALONG AND S OF A SLOWLY ADVANCING COLD FRONT AS THE
ASSOCIATED SURFACE LOW RIDES NE ALONG THE BOUNDARY PROGGED TO BE
FROM NORTHERN LAKE MI SW TO LOW PRESSURE IN NE MO BY EVENING WILL
CONTINUE TO SPREAD AN INCREASING AREA OF RAIN AND THUNDERSTORMS
INTO THE LOCAL AREA DURING THE LATER AFTERNOON. THE AREA OF
PRECIPITATION WILL BE SHIFTING NE AND E ACROSS THE LOCAL AREA
DURING THE EARLY TO MID EVENING AS THE SURFACE LOW CONTINUES NE
ALONG THE BOUNDARY TO SOUTHERN LAKE MI PULLING A COLD FRONT
ACROSS NW AND FAR NE IL BY 06Z.
S TO SW WINDS SHOULD CONTINUE TO GUST AT 20-25KT THROUGH THE DAY
THEN DIMINISH THIS EVENING AS THE PRESSURE GRADIENT DECREASES AS
THE FRONT APPROACHES. THE COLD FRONT IS EXPECTED TO PASS ACROSS
THE LOCAL AREA AROUND 07Z WITH A WIND SHIFT TO OUT OF THE W AND
NW. IFR TO LIFR CONDITIONS ARE ANTICIPATED TO RETURN FOR LATER
EVENING AND OVERNIGHT.
TRS
//ORD AND MDW CONFIDENCE...UPDATED 12Z...
* MEDIUM CONFIDENCE IN CIG/VSBY TRENDS.
* MEDIUM CONFIDENCE SCATTERED SHOWERS AND THUNDERSTORMS WILL NOT
BE IN CLOSE PROXIMITY OF THE CHI TERMINALS UNTIL LATER AFTERNOON.
* HIGH CONFIDENCE IN A PERIOD OF RA/+RA WITH EMBEDDED TS LATE
AFTERNOON INTO LATER EVENING.
* MEDIUM CONFIDENCE IN TIMING OF ARRIVAL OF WIDESPREAD RAIN AND
EMBEDDED THUNDERSTORMS.
TRS
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT...VFR.
THURSDAY...VFR.
FRIDAY...CHANCE OF ACCUMULATING SNOW AND MVFR/IFR CONDITIONS AT NIGHT.
SATURDAY...CHANCE OF ACCUMULATING SNOW AND MVFR/IFR CONDITIONS
DURING THE DAY.
SUNDAY...VFR.
MONDAY...VFR.
TRS
&&
.MARINE...
300 AM CST
LOW PRESSURE INCHES OVER IOWA...WILL CONTINUE TO TRACK NORTHEAST
TO SOUTHERN ONTARIO BY THIS EVENING...DRAGGING A WARM FRONT NORTH
ACROSS LAKE MICHIGAN...BRINGING A SURGE OF UNSEASONABLY WARM AND
HUMID AIR TO THE GREAT LAKES. AN ASSOCIATED COLD FRONT TRAILS BACK
TO ANOTHER LOW DEVELOPING OVER THE SOUTH HIGH PLAINS. THIS SECOND
LOW IS EXPECTED TO TRACK NORTHEAST ACROSS THE FAR SOUTHERN TIP OF
THE LAKE LATE TONIGHT WHILE DRAGGING A STRONG COLD FRONT IN IT`S
WAKE. FOLLOWING THE PASSAGE OF THIS SYSTEM...COLD HIGH PRESSURE
WILL BUILD OUT OF CANADA AND SPREAD ACROSS THE UPPER MISSISSIPPI
VALLEY AND WESTERN GREAT LAKES WEDNESDAY AND WEDNESDAY NIGHT. THE
COMBINATION OF THE EXITING LOW...THE BUILDING HIGH AND THE INFLUX
OF MUCH COOLER AIR WILL BRING NORTHWEST GALES TO THE ENTIRE LAKE
BY WEDNESDAY MORNING. GALES SHOULD PERSIST OVER THE LAKE THROUGH
LATE WEDNESDAY NIGHT. THE HIGH PRESSURE WILL THEN SPREAD INTO THE
CENTRAL PLAINS AND MISSOURI VALLEY ON THURSDAY.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLOOD WATCH...ILZ003-ILZ004-ILZ008-ILZ010-ILZ011-ILZ019...NOON
TUESDAY TO 4 AM WEDNESDAY.
FLOOD WATCH...ILZ005-ILZ006-ILZ012-ILZ013-ILZ014-ILZ020-ILZ021-
ILZ022-ILZ023-ILZ032-ILZ033-ILZ039...6 PM TUESDAY TO 4 AM
WEDNESDAY.
IN...FLOOD WATCH...INZ001-INZ002-INZ010-INZ011-INZ019...6 PM TUESDAY
TO 4 AM WEDNESDAY.
LM...DENSE FOG ADVISORY...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-
LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878
UNTIL 3 AM WEDNESDAY.
GALE WATCH...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...9 AM WEDNESDAY TO 3 AM
THURSDAY.
DENSE FOG ADVISORY...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565
UNTIL 9 PM TUESDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 4 AM WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
341 PM EST TUE JAN 29 2013
.UPDATE...
THE SYNOPSIS...NEAR TERM AND SHORT TERM SECTIONS HAVE BEEN
UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 337 PM EST TUE JAN 29 2013
NUMEROUS WEATHER HAZARDS WILL ACCOMPANY AN EXTREMELY POTENT SYSTEM
IMPACTING THE REGION THROUGH TOMORROW. VERY UNSEASONABLY WARM AND
MOIST CONDITIONS WILL BE IN PLACE THROUGH TONIGHT. AHEAD OF A
STRONG COLD FRONT SWEEPING THROUGH THE REGION...THE POTENTIAL WILL
EXIST FOR THUNDERSTORMS...HEAVY RAINFALL...FLOODING AND DAMAGING
WINDS. POTENTIAL FOR STRONG WINDS WILL CONTINUE BEHIND THE FRONTAL
BOUNDARY ON WEDNESDAY...AND FLOODING MAY LAST FOR SEVERAL DAYS OR
MORE.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 337 PM EST TUE JAN 29 2013
FOCUS OF THE NEAR TERM REMAINS ON SEVERE WEATHER CHANCES AS WELL AS
POSSIBLE HEAVY RAINFALL/FLOODING POSSIBILITIES TONIGHT. THE PERIOD
BEGINS WITH GOOD SHORT TERM MODEL AGREEMENT AS TO THE LOCATION OF
KEY FEATURES THAT MAY BRING POSSIBLE SEVERE TO PORTIONS OF THE
FORECAST AREA TONIGHT. AT 00Z/WED...THE LOW PRESSURE CENTER IS
PROGGED TO BE OVER CENTRAL MISSOURI...WITH ONGOING CONVECTION
POSSIBLY ALREADY IN THE FORM OF A SQUALL LINE ALONG A STRONG COLD
FRONT STRETCHED FROM NORTHWEST ILLINOIS...DOWN THROUGH CENTRAL
MISSOURI...INTO EASTERN OKLAHOMA/WESTERN ARKANSAS.
THERE DOES APPEAR TO BE SOME DIFFERENCES IN SPEED/TIMING OF THE
FRONT INTO THE FORECAST AREA...WITH THE HRRR AND RAP INTO THE AREA A
BIT QUICKER THE THE NAM AND GFS. PERSONAL EXPERIENCE HAS SHOWN THAT
THESE COLD FRONT/SQUALL LINE FEATURES TEND TO COME IN A BIT QUICKER
THAN SOMETIMES EXPECTED. THEREFORE...DECIDED TO TREND TOWARD THE
HRRR/RUC SOLNS.
AS WAS MENTIONED IN PREVIOUS DISCUSSIONS...DYNAMICS WILL NOT BE AN
ISSUE WITH THIS SYSTEM AS THE FRONT APPROACHES. A LOW LEVEL JET AOA
80 KTS AT 850 MB IS EXPECTED TO DEVELOP OUT AHEAD OF THE FRONT THIS
EVENING AND WILL TRANSLATE INTO OUR AREA TONIGHT. WITH 50 KT WINDS
LOCATED APPROXIMATELY 1000-1500 FEET ABOVE THE SURFACE
TONIGHT...DAMAGING WINDS MAY BECOME A REAL THREAT WITH ANY STORMS
THAT ARE ABLE TO REMAIN ORGANIZED AS THEY PUSH INTO THE FORECAST
AREA. ONE LIMITING FACTOR FOR CONVECTION REMAINING ORGANIZED INTO
THE OVERNIGHT HOURS IS INSTABILITY. SFC-BASED CAPE LOOKS TO BE IN
THE UNDER 200 J/KG RANGE...WHILE MUCAPE GIVES SLIGHTLY HIGHER
VALUES OF 200-400 J/KG AS THE FRONT MOVES INTO THE AREA. WITH THE
STRONG DYNAMICS AVAILABLE...WILL CONTINUE DAMAGING WINDS REFERENCE
IN THE GRIDS. ALSO KEEP IN MIND THAT WITH AMPLE LOW LEVEL
SHEAR...0-1 HELICITIES AOA 400-500 M2/S2...AN ISOLATED TORNADO
CANNOT BE RULED OUT.
THE BEST TIMING FOR SEVERE LOOKS TO START AT APPROXIMATELY 04-05Z
ACROSS WESTERN PORTIONS OF THE FORECAST AREA...TO ABOUT 10-11Z OVER
THE EAST. JUST ONE OTHER NOTE TO MENTION...THE HRRR ILLUSTRATES A
LINE OF CONVECTION DEVELOPING OUT AHEAD OF THE MAIN SQUALL LINE. TO
A LESSER EXTENT...THE RAP ALSO DEPICTS A SIMILAR SCENARIO. WHILE
THIS FORECAST HAS TAKEN THIS INTO CONSIDERATION...IT COULD STILL
ALLOW FOR AN EARLIER ONSET THAN FORECAST.
HEAVY RAINFALL IS ALSO IN PLAY TONIGHT AS MOISTURE HAS CONTINUED TO
STREAM NORTH INTO THE AREA. A PACIFIC TROPICAL PLUME OF MOISTURE HAS
BEEN EVIDENT ALL DAY ON WATER VAPOR IMAGERY STREAMING NORTHWEST INTO
LOWER MISSOURI/MID MISSISSIPPI/OHIO RIVER VALLEY STATES. COUPLE THAT
WITH 60 DEGREE DEWPOINTS CURRENTLY ON THE SOUTHWESTERN DOORSTEP OF
THE FORECAST AREA. PWATS TONIGHT AHEAD OF THE FRONT LOOK TO REACH
UPWARDS OF 1.40-1.50 INCHES...YIELDING A PERCENT OF NORMAL OF AROUND
300 PERCENT. WOULD NOT BE SURPRISED TO SEE A WIDESPREAD 1 TO 1.5
INCH RAINFALL...WITH SOME LOCALLY HIGHER AMOUNTS POSSIBLE.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY/...
ISSUED AT 337 PM EST TUE JAN 29 2013
SHORT TERM PERIOD SEES A DIFFERENT SET OF CHALLENGES. ONE OF THE
INITIAL CHALLENGES WILL BE STRONG WINDS AFTER THE COLD FRONT SWEEPS
THROUGH THE AREA AND A DRY SLOT APPROACHES THE FORECAST AREA DURING
THE AFTERNOON HOURS. SUSTAINED WINDS AROUND 20-25 KTS...WITH THE
POSSIBILITY TO TAP 40 KT WINDS FROM APPROX 850 MB AS BOUNDARY LAYER
MIXES OUT. A WIND ADVISORY MAY BE NEED FOR A TIME IN THE LATE
MORNING TO EARLY EVENING HOURS ON WEDNESDAY.
ADDITIONALLY...SOME LIGHT SNOW SHOWERS MAY WRAP AROUND AND AFFECT
MAINLY NORTHERN PORTIONS OF THE FORECAST AREA WEDNESDAY NIGHT AS THE
UPPER TROUGH FINALLY PASSES THROUGH. NOT CURRENTLY EXPECTING MUCH IN
THE WAY OF ACCUMULATION.
ANOTHER UPPER TROUGH AND COLD FRONT PUSHES INTO THE THROUGH THE AREA
LATE THURSDAY INTO THURSDAY NIGHT...BRINGING AN ADDITIONAL CHANCE
FOR SNOW AND FALLING TEMPS.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
ISSUED AT 144 PM EST TUE JAN 29 2013
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
THE EXTENDED PERIOD WILL NOT BE NEARLY AS ACTIVE AS THE FIRST FEW
DAYS OF THE FORECAST. FIRST OFF A SHORT WAVE TROUGH MOVING THROUGH
THE GREAT LAKES REGION MAY BRING A FEW SNOW SHOWERS TO CENTRAL
INDIANA AT THE BEGINNING OF THIS PERIOD. TEMPS/THICKNESS ALL LOOK
COLD ENOUGH FOR PLAIN SNOW DURING THIS TIME. ATTM ACCUMULATIONS
APPEAR TO BE AN INCH OR LESS. AFTER A COLD SHOT OF AIR THU AND
FRIDAY...TEMPERATURES WILL GRADUALLY MODERATE TO CLIMO OVER THE
WEEKEND AND INTO NEXT WEEK. SECOND HALF OF THE WEEKEND LOOKS DRY
AND INTO EARLY NEXT WEEK. ENSEMBLES SHOW SOME PRECIP BY NEXT
MONDAY/MONDAY NIGHT. TEMPERATURES LOOK WARM ENOUGH FOR A
SNOW/RAIN MIX ACROSS A GOOD PORTION OF THE AREA. HAVE SMALL
MINIMAL PRECIP CHANCES IN DURING THIS TIME.
&&
.AVIATION /DISCUSSION FOR THE 29/21Z TAF UPDATE/...
ISSUED AT 316 PM EST TUE JAN 29 2013
UPDATE...
NO CHANGES.
PREVIOUS DISCUSSION...
AVIATION FORECAST BASICALLY LOOKS RIGHT ON TRACK WITH ONLY A FEW
MINOR TWEAKS MADE. MVFR CEILINGS THROUGH EARLY EVENING...THEN IFR
CEILINGS AS RA...SCATTERED THUNDERSTORMS AND WIND GUSTS TO 35 KNOTS
DEVELOP LATER TONIGHT. OPTED TO REMOVE MUCH OF THE VCSH AND EVEN
VCTS MENTION THIS AFTERNOON AND PUSH BACK TIMING FOR VCSH TO THIS
EVENING WITH VCTS TO ARRIVE WITH MAIN PUSH AFTER MIDNIGHT, ALONG
WITH MODERATE TO HEAVY RAINFALL. MODELS INDICATE NUMEROUS SHOWERS
AND SCATTERED THUNDERSTORMS WITH COLD FRONT OVERNIGHT. IFR
CEILINGS RAIN AND THUNDERSTORMS SHOULD SPREAD INTO KLAF AND KHUF
THIS EVENING AND ELSEWHERE AFTER MIDNIGHT.
SOUTHERLY WINDS WILL CONTINUE TO INCREASE TO 20 TO 30 KNOTS THIS
AFTERNOON AND EVEN HIGHER WITH COLD FRONT OVERNIGHT. A LOW LEVEL JET
WILL PRODUCE LOW LEVEL WIND SHEAR ONCE AGAIN OVERNIGHT WITH 60 KT
AROUND 2K FT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
FLOOD WATCH FROM 7 PM EST THIS EVENING THROUGH WEDNESDAY MORNING
FOR INZ021-028>031-035>049-051>057-060>065-067>072.
&&
$$
SYNOPSIS...MRD
NEAR TERM...MRD
SHORT TERM...MRD
LONG TERM....SMF
AVIATION...SMF/TDUD
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
438 AM CST TUE JAN 29 2013
.SYNOPSIS...
VERY...VERY ACTIVE WEATHER TODAY. THIS MORNING A SURFACE LOW IS
LOCATED OVER NORTHERN IOWA NEAR KMCW AS OF 10Z...WITH A WARM FRONT
DRAPED FROM IT SOUTHEAST ACROSS THE NORTHERN COUNTIES OF THE
FORECAST AREA...GRADUALLY MOVING NORTH. DENSE FOG IS AFFECTING AREAS
IN THE IMMEDIATE VICINITY OF THE FRONT...THUS THE DENSE FOG ADVISORY
THAT CONTINUES UNTIL 6 AM. DEWPOINTS ON THE SOUTH SIDE OF THIS FRONT
ARE IN THE MID 40S TO MID 50S...WITH TEMPERATURES IN THE UPPER 40S
TO NEAR 60. A STRONG COLD FRONT IS DRAPED SOUTH FROM THE SURFACE
LOW BACK INTO NORTHWEST MISSOURI AND INTO KANSAS...WITH STRONG WEST
WINDS BEHIND IT. IN THE WARM SECTOR WE HAVE SCATTERED SHOWER AND
THUNDERSTORM ACTIVITY...WHICH HAS SO FAR PRODUCED MAINLY SMALL HAIL
REPORTS. ..LE..
&&
.SHORT TERM...TODAY...
TODAY IS GOING TO BE A VERY BUSY DAY AS WELL...WITH THE COLD FRONT
SLOWLY BEGINNING TO PLOW INTO THE FORECAST AREA WITH THIS VERY WARM
MOIST AIRMASS IN PLACE. THIS MORNING THE WARM FRONT SHOULD PUSH
NORTH OF THE FORECAST AREA FAIRLY EARLY...ALLOWING THE FOG TO
DISSIPATE. THE CURRENT SHOWER AND THUNDERSTORM ACTIVITY IS JUST THE
SECOND WAVE OF ACTIVITY THAT CAN BE EXPECTED TO AFFECT THE AREA WITH
THIS EVENT. SCATTERED ACTIVITY WILL LIKELY CONTINUE TO MOVE ACROSS
THE FORECAST AREA THIS MORNING. HOWEVER THIS AFTERNOON THE FRONT
SHOULD REALLY LIGHT UP. THIS ALREADY WARM AIRMASS IS LIKELY TO
DEVELOP MUCAPE VALUES OF 500-1000J/KG WITH HIGH TEMPERATURES IN THE
60S IN THE WARM SECTOR. THEN...A NICE SHORTWAVE AND EXIT REGION OF
AN UPPER LEVEL JET COME ACROSS THIS NICE WARM AIRMASS...WE ARE GOING
TO GET WIDESPREAD SHOWER AND THUNDERSTORM DEVELOPMENT. REFER TO THE
SPC DAY 1 OUTLOOK FOR DETAILS...BUT IN THIS AREA WE ARE LOOKING AT
STORMS WITH STRONG WINDS AND SMALL HAIL AS THE MAIN THREAT.
THUNDERSTORMS WITH THIS ACTIVITY WILL BE TAPPING INTO VERY HIGH
PRECIPITABLE WATER VALUE AIR FOR THIS TIME OF YEAR...AND HEAVY
RAINFALL IS EXPECTED THIS AFTERNOON AND EVENING. SEE THE HYDRO
SECTION BELOW FOR MORE INFORMATION. HAVE ALREADY MENTIONED HIGH
TEMPERATURES...WHAT I HAVE FORECASTED FOR TODAY IS GOING TO BREAK
RECORDS. UPSTREAM IN MISSOURI YESTERDAY HIGH TEMPS ROSE INTO THE 70S
NEARLY EVERYWHERE...SO DO NOT THINK THAT HIGHS IN THE MID-UPPER 60S
IS UNREASONABLE GIVEN THE AIRMASS THAT WE WILL HAVE. ..LE..
.LONG TERM...TONIGHT THROUGH NEXT SATURDAY...
A VERY INTERESTING FCST TONIGHT THROUGH WEDNESDAY NIGHT WITH
TEMPERATURES FALLING THROUGHOUT THE ENTIRE TIME FRAME.
THE COLD FRONT WILL BE EAST OF THE MISSISSIPPI BY THIS EVENING.
NUMEROUS SHOWERS/THUNDERSTORMS WILL BE SEEN AHEAD OF THE FRONT WITH
HEAVY RAIN INTO THE FIRST PART OF THE EVENING. BY MID EVENING
TEMPERATURES MAY HAVE FALLEN ENOUGH TO ALLOW A MIX TO DEVELOP OVER
THE NORTHWEST THIRD OF THE CWFA. AS TEMPERATURES CONTINUE TO FALL
THE RAIN WILL CHANGE OVER TO SNOW OVER ROUGHLY THE NORTHWEST 60
PERCENT OF THE CWFA BY SUNRISE WEDNESDAY. A MIX OR JUST RAIN WILL BE
OCCURRING OVER THE FAR EAST/SOUTHEAST.
ON WEDNESDAY...THE DEFORMATION ZONE ASSOCIATED WITH THE SFC LOW WILL
MOVE ACROSS ROUGHLY THE NORTHWEST 40 PERCENT OF THE CWFA. THE TIME
PERIOD JUST PRIOR TO DAWN AND THROUGH MID DAY WILL BE WHEN MOST OF
THE SNOW ACCUMULATION OCCURS.
STRONG CAA BEHIND THE DEPARTING LOW ON WEDNESDAY WILL RESULT IN A
HIGH TEMPERATURE FOR THE DAYLIGHT HOURS OCCURRING JUST AFTER
SUNRISE. TEMPERATURES WILL FALL FOR THE REMAINDER OF THE DAY. WINDS
WILL BE QUITE STRONG WHICH WILL REDUCE VISIBILITIES IN RURAL AREAS.
BY LATE WEDNESDAY AFTERNOON THE SNOW WILL SLOWLY TAPER TO FLURRIES
THAT WILL END DURING THE EVENING HOURS. LATE WEDNESDAY NIGHT WILL BE
DRY AS THE CANADIAN/ARCTIC HIGH BEGINS BUILDING INTO THE MIDWEST.
AS FOR SNOW AMOUNTS...AREAS GENERALLY WEST OF A DUBUQUE TO
WILLIAMSBURG LINE SHOULD SEE 3-4 INCHES WITH POSSIBLY A FEW 5 INCH
AMOUNTS. SOUTHEAST OF THAT LINE AND UP TO A FREEPORT IL TO MEMPHIS
MO LINE 2-3 INCHES ARE EXPECTED. SOUTHEAST OF A FREEPORT TO MEMPHIS
LINE 1-2 INCHES ARE EXPECTED.
DRY BUT COLD CONDITIONS WILL BE SEEN THURSDAY/THURS NIGHT AS THE
CANADIAN/ARCTIC HIGH BUILDS INTO THE MIDWEST.
FRIDAY ON...
MODEL CONSENSUS HAS DRY CONDITIONS ON FRIDAY AHEAD OF AN APPROACHING
CLIPPER SYSTEM. THIS SYSTEM WILL MOVE THROUGH THE AREA FRIDAY NIGHT
AND SATURDAY. THE CURRENT MODEL CONSENSUS SCHC POPS LOOKS REASONABLE
AS WHERE THE CLIPPER TRACKS IS DEPENDENT UPON HOW DEEP THE LONGWAVE
TROF OVER THE EASTERN CONUS BECOMES.
SUNDAY THROUGH MONDAY THE MODEL CONSENSUS CURRENTLY HAS DRY
CONDITIONS WITH MODERATING TEMPERATURES. HOWEVER...THERE ARE SEVERAL
DISTURBANCES MOVING THROUGH IN THE FLOW ALOFT WITH YET ANOTHER
CLIPPER TYPE SYSTEM. MOISTURE AVAILABILITY IS QUESTIONABLE SO THE
CURRENT DRY FCST LOOKS REASONABLE FOR NOW. ..08..
&&
.AVIATION... /ISSUED 1142 PM CST MON JAN 28 2013/
WARM FRONT LIFTING NORTH THROUGH IOWA/ILLINOIS WILL RESULT IN
VLIFR CONDITIONS IMPROVING TO VFR. PRIOR TO AND FOR AN HOUR OR TWO
BEHIND THE FRONTAL PASSAGE LLWS IS LIKELY. RAP MODEL TRENDS
SUGGEST NEW CONVECTION WILL DVLP THROUGH 12Z/29 WITH SOME TSRA
POSSIBLE. COLD FRONT TO MOVE THROUGH EASTERN IOWA/ILLINOIS FROM
15Z/29 TO 00Z/30 BRINGING ANOTHER THREAT OF TSRA. VFR CONDITIONS
WILL DETERIORATE TO MVFR FOLLOWING THE PASSAGE OF THE COLD FRONT.
AFT 06Z/30 CONDITIONS WILL DETERIORATE TO IFR/LIFR WITH SN. ..08..
&&
.HYDROLOGY...
AIRMASS THAT IS NOW IN PLACE OVER THE FORECAST AREA THIS MORNING HAS
COPIOUS MOISTURE...WITH DEWPOINTS IN THE MID 50S. LAST NIGHTS UPPER
AIR SOUNDINGS SHOWED THAT THE ENTIRE ATMOSPERE IS FAIRLY WELL LOADED
WITH MOISTURE...WITH PRECIPITABLE WATER VALUES THAT ARE 200-300
PERCENT OF NORMAL FOR THIS TIME OF YEAR. QPF FROM THE THUNDERSTORMS
ALONG AND AHEAD OF THE COLD FRONT IS LIKELY TO RANGE FROM 1 TO 2
INCHES OVER ABOUT THE SOUTHEASTERN THIRD TO HALF OF THE FORECAST
AREA. CURRENT TIMING INDICATES THAT THIS WILL FALL IN THE AFTERNOON
AND EVENING AS THE COLD FRONT PUSHES THROUGH THE AREA.
GIVEN THIS SCENARIO...THE ROCK RIVER BASIN IS AT GREATEST RISK FOR
POSSIBLE FLOODING...THOUGH THERE IS MUCH UNCERTAINTY OF HOW THE VERY
LOW RIVER LEVELS DUE TO THE RECENT DROUGHT AND THE FROZEN GROUND
WILL REACT ONCE THIS RAIN FALLS ON IT. AN ALMOST GREATER THREAT
WILL BE FLOODING OF URBAN AREAS AND SMALL STREAMS DUE TO HEAVY
RAINFALL RATES IN THE STRONGEST THUNDERSTORMS THIS AFTERNOON AND
EVENING. ..LE..
&&
.CLIMATE...
RECORD HIGHS FOR JANUARY 29...
MOLINE.........57 IN 1914
CEDAR RAPIDS...53 IN 1919
DUBUQUE........54 IN 1914
BURLINGTON.....59 IN 1917
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...DENSE FOG ADVISORY UNTIL 6 AM CST EARLY THIS MORNING FOR BENTON-
BUCHANAN-DELAWARE-DUBUQUE-JACKSON-JONES-LINN.
WINTER STORM WATCH FROM LATE TONIGHT THROUGH WEDNESDAY AFTERNOON
FOR CEDAR-DUBUQUE-JACKSON-JEFFERSON-JOHNSON-JONES-
WASHINGTON.
WINTER STORM WATCH FROM THIS EVENING THROUGH WEDNESDAY AFTERNOON
FOR BENTON-BUCHANAN-DELAWARE-IOWA-KEOKUK-LINN.
FLOOD WATCH FROM NOON CST TODAY THROUGH THIS EVENING FOR DES
MOINES-LEE.
IL...DENSE FOG ADVISORY UNTIL 6 AM CST EARLY THIS MORNING FOR CARROLL-
JO DAVIESS-STEPHENSON.
WINTER STORM WATCH FROM LATE TONIGHT THROUGH WEDNESDAY AFTERNOON
FOR JO DAVIESS.
FLOOD WATCH FROM NOON CST TODAY THROUGH THIS EVENING FOR BUREAU-
HANCOCK-HENDERSON-HENRY IL-MCDONOUGH-MERCER-PUTNAM-ROCK
ISLAND-WARREN-WHITESIDE.
MO...FLOOD WATCH FROM NOON CST TODAY THROUGH THIS EVENING FOR CLARK.
&&
$$
LE/08
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1142 PM CST MON JAN 28 2013
.AVIATION...
WARM FRONT LIFTING NORTH THROUGH IOWA/ILLINOIS WILL RESULT IN
VLIFR CONDITIONS IMPROVING TO VFR. PRIOR TO AND FOR AN HOUR OR TWO
BEHIND THE FRONTAL PASSAGE LLWS IS LIKELY. RAP MODEL TRENDS
SUGGEST NEW CONVECTION WILL DVLP THROUGH 12Z/29 WITH SOME TSRA
POSSIBLE. COLD FRONT TO MOVE THROUGH EASTERN IOWA/ILLINOIS FROM
15Z/29 TO 00Z/30 BRINGING ANOTHER THREAT OF TSRA. VFR CONDITIONS
WILL DETERIORATE TO MVFR FOLLOWING THE PASSAGE OF THE COLD FRONT.
AFT 06Z/30 CONDITIONS WILL DETERIORATE TO IFR/LIFR WITH SN. ..08..
&&
.PREV DISCUSSION... /ISSUED 924 PM CST MON JAN 28 2013/
UPDATE...
UPDATED THE NPW JUST BEFORE 9 PM TO DROP THE CLARK AND SCOTLAND
COUNTIES. REPORTS FROM THAT AREA SUGGESTED VISIBILITIES WERE
IMPROVING ALTHOUGH SOME PATCHY FOG WAS STILL OCCURRING. THE REST
OF THE ADVISORY FOR THE SOUTHERN COUNTIES WAS EXTENDED TO 3 AM.
HOWEVER...RECENT OBS FROM KBRL SHOW VSBYS THERE UP TO 3SM. IF THIS
TREND CONTINUES PART OF THE ADVISORY WILL LIKELY BE DROPPED BEFORE
MIDNIGHT.
THUNDERSTORMS CONTINUE TO ERUPT OVER THE CENTRAL AND NORTHERN
CWFA. RADAR DATA SUGGESTS THAT SOME OF THE STORMS CONTAIN SMALL
HAIL BUT HAVE YET TO RECEIVE ANY REPORTS.
DLF
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...DENSE FOG ADVISORY UNTIL 3 AM CST TUESDAY FOR BENTON-BUCHANAN-
CEDAR-CLINTON-DELAWARE-DUBUQUE-IOWA-JACKSON-JOHNSON-JONES-
KEOKUK-LINN-LOUISA-MUSCATINE-SCOTT-WASHINGTON.
IL...DENSE FOG ADVISORY UNTIL 3 AM CST TUESDAY FOR BUREAU-CARROLL-
HENRY IL-JO DAVIESS-MERCER-PUTNAM-ROCK ISLAND-STEPHENSON-
WHITESIDE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
656 PM EST WED JAN 30 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 441 PM EST WED JAN 30 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH FROM
HUDSON BAY AND NW ONTARIO THROUGH MN/IA INTO ERN OK. THE POTENT
SHORTWAVE TROUGH OVER SW WI AND ASSOCIATED DEFORMATION ZONE
CONTINUED TO SUPPORT A HEAVY SNOW BAND FROM ERN WI INTO THE E HALF
OF UPPER MI. LIGHTER SNOW WAS OBSERVED OVER THE WEST HALF OF UPPER
MI. SNOW TOTALS OF AROUND 6 INCHES WERE OBSERVED BY 21Z FROM THE NWS
MQT OFFICE TO MNM...GLADSTONE AND MANISTIQUE. A TIGHT GRADIENT BTWN
THE 987 MB LOW OVER SRN LOWER MI AND ARCTIC HIGH PRES BUILDING INTO
THE PLAINS HAS RESULTED IN GALES ACROSS LAKE SUPERIOR AND GUSTY N
WINDS TO 30 MPH OVER MOST OF THE CWA.
TONIGHT AND THURSDAY...THE HEAVY SNOW BAND WHICH CORRELATED WELL WITH
NAM/RUC 700-600 MB FGEN IS EXPECTED TO SHIF QUICKLY TO THE NORTHEAST
THIS EVENING LEAVING MAINLY LIGHT SNOW THAT WILL DIMINISH BTWN
00Z-03Z. HOWEVER...COLDER AIR MOVING IN ON THE STRONG N WINDS
COMBINED WITH 850 MB TEMPS TO AROUND -15C WILL CONTINUE TO SUPPORT
LCLY HIGHER SNOWFALL RATES N CNTRL...ESPECIALLY VCTY MARQUETTE THIS
EVENING WITH CYCLONIC LOW LEVEL 340-350 WIND DIRECTION NEAR THE
SHORE. FAVORABLE UPSLOPE NRLY FLOW INTO THE FAR WEST SHOULD ALSO
BRING INCREASING LES INTO IWD. RADAR TRENDS AND MODELS SUGGEST
ADDITIONAL SYNOPTIC SNOW POTENTIAL IN THE 1 TO 3 INCH RANGE BTWN 21Z-
03Z. HOWEVER AREAS WITH LAKE CONTRIBUTION COULD SEE ANOTHER 3 TO 6
INCHES THROUGH 12Z/THU.
AS THE STRONGER SYNOPTIC FORCING WITH THE SHRTWV MOVES OUT THIS
EVENING...HEADLINES ARE SET TO EXPIRE BY AROUND 03Z OVER THE S CWA.
A TRANSISTION TO LAKE EFFECT SNOW WILL CONTINUE OVERNIGHT WITH
FAVORABLE CONDITION PERSISTING INTO THURSDAY. ANOTHER TRAILING
SHRTWV SLIDING SE INTO THE UPPER LAKES WILL MAINTAIN 850-700 MB
MOISTURE AND INVERSION HEIGHTS AOA 10K FT. WITH THE WINDS BACKING
SLIGHTLY TO 340-330 THE HEAVIER LES WILL CONTINUE TO FOCUS INTO THE
FAR WEST AND TO AREAS EAST OF MARQUETTE. 850 MB TEMPS FALLING TO
AROUND -20C MAY SHRINK THE DGZ LAYER INTO THE 1K-3K RANGE BUT STILL
SHOULD BE SUFFICIENT FOR LSR VALUES CLOSE TO 25/1. ADDITIONAL
SNOWFALL AMOUNTS OF 3 TO 7 INCHES ARE POSSIBLE.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 441 PM EST WED JAN 30 2013
MODELS ARE IN GOOD GENERAL AGREEMENT THROUGH THE EXTENDED WITH DEEP
UPPER TROUGH STARTING THE PERIOD FRI AND GRADUALLY BREAKING DOWN AND
SHIFTING WEST THROUGH NEXT WED...AS AN UPPER RIDGE MOVES INTO THE
WRN CONUS.
GOOD NW WIND LES WILL BE ONGOING INTO THU NIGHT GIVEN NW LOW LEVEL
FLOW...AMPLE MOISTURE AND 825MB INVERSION TOP TEMPS AROUND -25C.
LATE THU NIGHT AND FRI...A SFC HIGH WILL MOVE S OF THE CWA WHILE A
SHORTWAVE TROUGH DIVES IN FROM THE NW FORMING A MESO-LOW OVER ERN
LAKE SUPERIOR LATE FRI. THIS TURNS THE NW WINDS WLY BY FRI
AFTERNOON...FOCUSING LES OVER THE KEWEENAW AND FAR NE UPPER MI.
PRIOR WIND SHIFT...THE BEST LES WILL BE FOCUSED OVER ONTONAGON AND
GOGEBIC COUNTIES AND OVER ERN UPPER MI FROM MUNISING TO GRAND
MARAIS. LES SHOULD INITIALLY WEAKEN SOME LATE THU NIGHT AS RIDGING
MOVES INTO THE AREA...BUT WILL GET A BOOST FROM THE SHORTWAVE LATER
ON FRIDAY. THERE IS ALREADY A LES ADVISORY FOR ONTONAGON/GOGEBIC
COUNTIES THROUGH THU NIGHT...AND THAT STILL LOOKS FINE. BUT WILL
LIKELY ALSO NEED HEADLINES FOR THE ERN U.P. THU NIGHT INTO FRI. THE
KEWEENAW MAY ALSO NEED HEADLINES FRI INTO FRI NIGHT. WILL NOT ISSUE
ANY NEW HEADLINES AT THIS POINT GIVEN HEADLINES ALREADY IN EFFECT
OVER THE ERN U.P. AND SOME UNCERTAINTY AS TO THE RESIDENCE TIME AND
INTENSITY OF ANY STRONGER BANDS THAT MOVE ACROSS THE KEWEENAW.
THU NIGHT THROUGH FRI NIGHT LOOKS TO BE THE COLDEST PERIOD OF THE
NEXT WEEK. LOWS THU NIGHT AND FRI NIGHT LOOKS TO FALL TO THE TEENS
BELOW ZERO WITH WIND CHILLS TO -35F OVER PARTS OF THE INTERIOR.
HIGHS ON FRI LOOK TO BE AROUND ZERO OVER THE INTERIOR W...AND IN THE
LOW TEENS ABOVE ZERO E. WIND CHILL VALUES ARE CURRENTLY FORECAST TO
BE IN TEENS BELOW ZERO AT THE WARMEST FRI AFTERNOON OVER THE
INTERIOR W...AND IN THE SINGLE DIGITS BELOW ZERO E. WILL LIKELY NEED
SOME WIND CHILL ADVISORY HEADLINES UP WHERE THERE ARE NO OTHER
WINTER WX HEADLINES.
MODELS IN RELATIVELY GOOD AGREEMENT WITH A CLIPPER SHORTWAVE MOVING
THROUGH LATE SAT INTO EARLY SAT NIGHT...BUT ONLY MINOR SYNOPTIC SNOW
ACCUMULATIONS AND INCREASED NW WIND LES ARE EXPECTED TO RESULT FROM
THE SYSTEM.
SFC RIDGING MOVES OVER ON SUN AHEAD OF THE NEXT...STRONGER...CLIPPER
SYSTEM THAT MODEL DEPICT MOVING THROUGH. ALTHOUGH MODELS SEEM TO
AGREE FAIRLY WELL ON THE OVERALL TRACK AND INTENSITY OF THE
SYSTEM...THE 00Z/30 ECMWF IS 6-12 HOURS FASTER THAN THE 12Z/30 GFS.
SEVERAL INCHES OF SNOW MAY RESULT AREA WIDE FROM THIS SYSTEM.
MODELS THEN INDICATE...WITH GREATER UNCERTAINTY...ANOTHER CLIPPER
SYSTEM MOVING THROUGH SOMETIME MIDWEEK.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 655 PM EST WED JAN 30 2013
AT KIWD...LAKE EFFECT -SHSN WILL INCREASE TONIGHT AS COLDER AIR
FLOWS INTO THE AREA AND LOW-LEVEL WINDS BECOME MORE CYCLONIC. AS A
RESULT...MVFR CONDITIONS THIS EVENING SHOULD FALL TO IFR OVERNIGHT
THRU MUCH OF THE DAY THU. AT KCMX...LIFR CONDITIONS HAVE ALREADY
DEVELOPED AND WILL LIKELY CONTINUE THRU THE FCST PERIOD AS LAKE
EFFECT -SHSN CONTINUE UNDER INCREASINGLY COLDER AIR MASS. WITH THE
COLDER AIR...SNOWFLAKE SIZE WILL BE SMALL AND VERY EFFECTIVE AT
KEEPING VIS LOW. AT KSAW...SYNOPTIC SNOW SHIELD WILL BE EXITING
LEAVING LAKE EFFECT -SHSN LATE EVENING THRU THU. AS A RESULT...
EXPECT INITIAL LIFR CONDITIONS TO IMPROVE TO IFR THIS EVENING AND TO
MOSTLY MVFR OVERNIGHT THRU THU. AS IS TYPICAL FOR LAKE EFFECT
SNOW...EXPECT VIS AT ALL SITES TO BE HIGHLY VARIABLE AT TIMES AS
SNOW BANDS MOVE ACROSS THE AREA.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 441 PM EST WED JAN 30 2013
N TO NW GALES OF 35 TO 40 KNOTS WILL CONTINUE THROUGH MUCH OF
TONIGHT...WITH A FEW GALE FORCE GUSTS TO 35 KNOTS LINGERING E
THROUGH THURSDAY. LOW PRESSURE OVER LOWER MICHIGAN WILL LIFT
NORTHEAST INTO ONTARIO AND QUEBEC TONIGHT. WITH PLENTY OF
COLD AIR SINKING IN BEHIND THE LOW AND STRONG WINDS...HEAVY FREEZING
SPRAY WILL PREVAIL THROUGH THURSDAY NIGHT...AND MAY LINGER OVER THE
FAR EAST THROUGH FRIDAY NIGHT. A TROUGH WILL LINGER OVER LAKE
SUPERIOR THROUGH THURSDAY...AS STRONG HIGH PRESSURE SINKS ACROSS THE
PLAINS STATES. EXPECT THE HIGH PRESSURE SYSTEM TO WEAKEN SLIGHTLY
OVER THE MISSISSIPPI VALLEY FRIDAY...WHILE PUSHING A RIDGE ACROSS
WESTERN LAKE SUPERIOR. WEAK LOW PRESSURE WILL LINGER ACROSS EASTERN
LAKE SUPERIOR THROUGH SATURDAY. ANOTHER LOW PRESSURE TROUGH WILL
SINK SOUTHWARD FROM MANITOBA INTO THE UPPER GREAT LAKES SATURDAY
EVENING...BEFORE MOVING INTO THE LOWER GREAT LAKES DURING THE DAY
SUNDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 9 PM CST THIS EVENING FOR MIZ010-
011.
WINTER STORM WARNING UNTIL 10 PM EST /9 PM CST/ THIS EVENING FOR
MIZ012>014.
WINTER STORM WARNING UNTIL 7 AM EST THURSDAY FOR MIZ006-007-085.
LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST /6 AM CST/ FRIDAY FOR
MIZ002-009.
WINTER STORM WARNING UNTIL 1 AM EST THURSDAY FOR MIZ005.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST FRIDAY FOR
LSZ265>267.
GALE WARNING UNTIL 4 AM EST THURSDAY FOR LSZ264>267.
HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST /6 AM CST/ FRIDAY
FOR LSZ162-263-264.
GALE WARNING UNTIL 10 PM EST THIS EVENING FOR LSZ263.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...TITUS
AVIATION...ROLFSON
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
443 PM EST WED JAN 30 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 441 PM EST WED JAN 30 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH FROM
HUDSON BAY AND NW ONTARIO THROUGH MN/IA INTO ERN OK. THE POTENT
SHORTWAVE TROUGH OVER SW WI AND ASSOCIATED DEFORMATION ZONE
CONTINUED TO SUPPORT A HEAVY SNOW BAND FROM ERN WI INTO THE E HALF
OF UPPER MI. LIGHTER SNOW WAS OBSERVED OVER THE WEST HALF OF UPPER
MI. SNOW TOTALS OF AROUND 6 INCHES WERE OBSERVED BY 21Z FROM THE NWS
MQT OFFICE TO MNM...GLADSTONE AND MANISTIQUE. A TIGHT GRADIENT BTWN
THE 987 MB LOW OVER SRN LOWER MI AND ARCTIC HIGH PRES BUILDING INTO
THE PLAINS HAS RESULTED IN GALES ACROSS LAKE SUPERIOR AND GUSTY N
WINDS TO 30 MPH OVER MOST OF THE CWA.
TONIGHT AND THURSDAY...THE HEAVY SNOW BAND WHICH CORRELATED WELL WITH
NAM/RUC 700-600 MB FGEN IS EXPECTED TO SHIF QUICKLY TO THE NORTHEAST
THIS EVENING LEAVING MAINLY LIGHT SNOW THAT WILL DIMINISH BTWN
00Z-03Z. HOWEVER...COLDER AIR MOVING IN ON THE STRONG N WINDS
COMBINED WITH 850 MB TEMPS TO AROUND -15C WILL CONTINUE TO SUPPORT
LCLY HIGHER SNOWFALL RATES N CNTRL...ESPECIALLY VCTY MARQUETTE THIS
EVENING WITH CYCLONIC LOW LEVEL 340-350 WIND DIRECTION NEAR THE
SHORE. FAVORABLE UPSLOPE NRLY FLOW INTO THE FAR WEST SHOULD ALSO
BRING INCREASING LES INTO IWD. RADAR TRENDS AND MODELS SUGGEST
ADDITIONAL SYNOPTIC SNOW POTENTIAL IN THE 1 TO 3 INCH RANGE BTWN 21Z-
03Z. HOWEVER AREAS WITH LAKE CONTRIBUTION COULD SEE ANOTHER 3 TO 6
INCHES THROUGH 12Z/THU.
AS THE STRONGER SYNOPTIC FORCING WITH THE SHRTWV MOVES OUT THIS
EVENING...HEADLINES ARE SET TO EXPIRE BY AROUND 03Z OVER THE S CWA.
A TRANSISTION TO LAKE EFFECT SNOW WILL CONTINUE OVERNIGHT WITH
FAVORABLE CONDITION PERSISTING INTO THURSDAY. ANOTHER TRAILING
SHRTWV SLIDING SE INTO THE UPPER LAKES WILL MAINTAIN 850-700 MB
MOISTURE AND INVERSION HEIGHTS AOA 10K FT. WITH THE WINDS BACKING
SLIGHTLY TO 340-330 THE HEAVIER LES WILL CONTINUE TO FOCUS INTO THE
FAR WEST AND TO AREAS EAST OF MARQUETTE. 850 MB TEMPS FALLING TO
AROUND -20C MAY SHRINK THE DGZ LAYER INTO THE 1K-3K RANGE BUT STILL
SHOULD BE SUFFICIENT FOR LSR VALUES CLOSE TO 25/1. ADDITIONAL
SNOWFALL AMOUNTS OF 3 TO 7 INCHES ARE POSSIBLE.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 441 PM EST WED JAN 30 2013
MODELS ARE IN GOOD GENERAL AGREEMENT THROUGH THE EXTENDED WITH DEEP
UPPER TROUGH STARTING THE PERIOD FRI AND GRADUALLY BREAKING DOWN AND
SHIFTING WEST THROUGH NEXT WED...AS AN UPPER RIDGE MOVES INTO THE
WRN CONUS.
GOOD NW WIND LES WILL BE ONGOING INTO THU NIGHT GIVEN NW LOW LEVEL
FLOW...AMPLE MOISTURE AND 825MB INVERSION TOP TEMPS AROUND -25C.
LATE THU NIGHT AND FRI...A SFC HIGH WILL MOVE S OF THE CWA WHILE A
SHORTWAVE TROUGH DIVES IN FROM THE NW FORMING A MESO-LOW OVER ERN
LAKE SUPERIOR LATE FRI. THIS TURNS THE NW WINDS WLY BY FRI
AFTERNOON...FOCUSING LES OVER THE KEWEENAW AND FAR NE UPPER MI.
PRIOR WIND SHIFT...THE BEST LES WILL BE FOCUSED OVER ONTONAGON AND
GOGEBIC COUNTIES AND OVER ERN UPPER MI FROM MUNISING TO GRAND
MARAIS. LES SHOULD INITIALLY WEAKEN SOME LATE THU NIGHT AS RIDGING
MOVES INTO THE AREA...BUT WILL GET A BOOST FROM THE SHORTWAVE LATER
ON FRIDAY. THERE IS ALREADY A LES ADVISORY FOR ONTONAGON/GOGEBIC
COUNTIES THROUGH THU NIGHT...AND THAT STILL LOOKS FINE. BUT WILL
LIKELY ALSO NEED HEADLINES FOR THE ERN U.P. THU NIGHT INTO FRI. THE
KEWEENAW MAY ALSO NEED HEADLINES FRI INTO FRI NIGHT. WILL NOT ISSUE
ANY NEW HEADLINES AT THIS POINT GIVEN HEADLINES ALREADY IN EFFECT
OVER THE ERN U.P. AND SOME UNCERTAINTY AS TO THE RESIDENCE TIME AND
INTENSITY OF ANY STRONGER BANDS THAT MOVE ACROSS THE KEWEENAW.
THU NIGHT THROUGH FRI NIGHT LOOKS TO BE THE COLDEST PERIOD OF THE
NEXT WEEK. LOWS THU NIGHT AND FRI NIGHT LOOKS TO FALL TO THE TEENS
BELOW ZERO WITH WIND CHILLS TO -35F OVER PARTS OF THE INTERIOR.
HIGHS ON FRI LOOK TO BE AROUND ZERO OVER THE INTERIOR W...AND IN THE
LOW TEENS ABOVE ZERO E. WIND CHILL VALUES ARE CURRENTLY FORECAST TO
BE IN TEENS BELOW ZERO AT THE WARMEST FRI AFTERNOON OVER THE
INTERIOR W...AND IN THE SINGLE DIGITS BELOW ZERO E. WILL LIKELY NEED
SOME WIND CHILL ADVISORY HEADLINES UP WHERE THERE ARE NO OTHER
WINTER WX HEADLINES.
MODELS IN RELATIVELY GOOD AGREEMENT WITH A CLIPPER SHORTWAVE MOVING
THROUGH LATE SAT INTO EARLY SAT NIGHT...BUT ONLY MINOR SYNOPTIC SNOW
ACCUMULATIONS AND INCREASED NW WIND LES ARE EXPECTED TO RESULT FROM
THE SYSTEM.
SFC RIDGING MOVES OVER ON SUN AHEAD OF THE NEXT...STRONGER...CLIPPER
SYSTEM THAT MODEL DEPICT MOVING THROUGH. ALTHOUGH MODELS SEEM TO
AGREE FAIRLY WELL ON THE OVERALL TRACK AND INTENSITY OF THE
SYSTEM...THE 00Z/30 ECMWF IS 6-12 HOURS FASTER THAN THE 12Z/30 GFS.
SEVERAL INCHES OF SNOW MAY RESULT AREA WIDE FROM THIS SYSTEM.
MODELS THEN INDICATE...WITH GREATER UNCERTAINTY...ANOTHER CLIPPER
SYSTEM MOVING THROUGH SOMETIME MIDWEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1251 PM EST WED JAN 30 2013
A LARGE AREA OF SYNOPTIC SCALE SNOW WILL MOVE THROUGH THE REGION
THIS AFTERNOON AND EVENING. NRLY FLOW WILL LEAD TO POTENTIAL FOR
GREATER SNOWFALL RATES AND LOWER VSBY WITH LAKE ENHANCED SNOW AT IWD
AND SAW. SO...MAINLY IFR CONDITIONS ARE EXPECTED WITH LIFR VSBY AT
TIMES. SNOW WILL TRANSITION TO LAKE EFFECT SNOW TONIGHT AND CONTINUE
INTO THURSDAY KEEPING MVFR CONDITIONS WITH OCNL IFR. WITH WINDS
BACKING MORE TO THE NW CONDITIONS SHOULD GRADUALLY IMPROVE AT SAW
LATE TONIGHT.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 441 PM EST WED JAN 30 2013
N TO NW GALES OF 35 TO 40 KNOTS WILL CONTINUE THROUGH MUCH OF
TONIGHT...WITH A FEW GALE FORCE GUSTS TO 35 KNOTS LINGERING E
THROUGH THURSDAY. LOW PRESSURE OVER LOWER MICHIGAN WILL LIFT
NORTHEAST INTO ONTARIO AND QUEBEC TONIGHT. WITH PLENTY OF
COLD AIR SINKING IN BEHIND THE LOW AND STRONG WINDS...HEAVY FREEZING
SPRAY WILL PREVAIL THROUGH THURSDAY NIGHT...AND MAY LINGER OVER THE
FAR EAST THROUGH FRIDAY NIGHT. A TROUGH WILL LINGER OVER LAKE
SUPERIOR THROUGH THURSDAY...AS STRONG HIGH PRESSURE SINKS ACROSS THE
PLAINS STATES. EXPECT THE HIGH PRESSURE SYSTEM TO WEAKEN SLIGHTLY
OVER THE MISSISSIPPI VALLEY FRIDAY...WHILE PUSHING A RIDGE ACROSS
WESTERN LAKE SUPERIOR. WEAK LOW PRESSURE WILL LINGER ACROSS EASTERN
LAKE SUPERIOR THROUGH SATURDAY. ANOTHER LOW PRESSURE TROUGH WILL
SINK SOUTHWARD FROM MANITOBA INTO THE UPPER GREAT LAKES SATURDAY
EVENING...BEFORE MOVING INTO THE LOWER GREAT LAKES DURING THE DAY
SUNDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 9 PM CST THIS EVENING FOR MIZ010-
011.
WINTER STORM WARNING UNTIL 10 PM EST /9 PM CST/ THIS EVENING FOR
MIZ012>014.
WINTER STORM WARNING UNTIL 7 AM EST THURSDAY FOR MIZ006-007-085.
LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST /6 AM CST/ FRIDAY FOR
MIZ002-009.
WINTER STORM WARNING UNTIL 1 AM EST THURSDAY FOR MIZ005.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST FRIDAY FOR
LSZ265>267.
GALE WARNING UNTIL 4 AM EST THURSDAY FOR LSZ264>267.
HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST /6 AM CST/ FRIDAY
FOR LSZ162-263-264.
GALE WARNING UNTIL 10 PM EST THIS EVENING FOR LSZ263.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...TITUS
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
551 PM EST TUE JAN 29 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 504 PM EST TUE JAN 29 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH FROM
NE MANITOBA THROUGH THE PLAINS INTO NEW MEXICO. WEAK SHRTWVS
EMBEDDED IN THE SW FLOW FROM THE SRN PLAINS INTO THE GREAT LAKES
SUPPORTED AREAS OF SHRA/TSRA NEAR A SFC FRONT EXTENDING FROM NE WI
THROUGH CNTRL MO AND INTO CNTRL OK. THE MAIN SHRTWV WAS REMAINED
NEAR THE BASE OF THE TROUGH...MOVING TOWARD THE TX/OK PANHANDLE.
PCPN HAD DIMINISHED OVER UPPER MICHIGAN WITH MAINLY SOME SCT LIGHT
SHOWERS MOVING THROUGH FAR SRN UPPER MI. WEST WINDS AND SLIGHTLY
DRIER AIR BEHIND A TROUGH SLIDING TO NEAR P53-ISQ HAS BROUGHT
IMPROVED VISIBILITIES THROUGH THE CNTRL AND WEST CWA.
ALTHOUGH THE 12Z ECMWF WAS A BIT SLOWER THAN THE 12Z GFS...THE MODELS
WERE IN RELATIVELY GOOD AGREEMENT WITH REGARD TO OVERALL PCPN/SNOW
POTENTIAL ACROSS THE CWA. ALTHOUGH THE 12Z NAM HAD SHIFTED THE
HEAVIER QPF AXIS WELL TO THE EAST...THE 18Z RUN HAS COME BACK INTO
BETTER AGREEMENT WITH THE GLOBAL MODELS. MODELS DIFFICULTY IN
HANDLING THE CONVECTION AND HEAVY RAIN NEAR THE FRONT MAY ACCOUNT
FOR A PORTION OF THE INCONSISTENCY AND VARIABILITY AND STILL LEADS
GREATER THAN USUAL UNCERTAINTY. ALTHOUGH THERE IS MODERATE
CONFIDENCE WITH THE MULTI-MODEL BLEND OF THE GFS/ECMWF/NAM/REG-GEM
USED FOR QPF...TIMING OF THE HEAVIER PCPN ONSET MAY BE A BIT DELAYED
GIVEN ECMWF/NAM TRENDS.
THE STRONGEST DYNAMICS ARE EXPECTED TO DEVELOP BTWN 12Z-18Z/WED AS
THE NM SHRTWV LIFTS TOWARD THE GREAT LAKES. A COUPLED UPPER LEVEL
JET STRUCTURE AND RESULTING STRONG 800-600 MB FGEN WILL SUPPORT A
PERIOD OF MODERATE TO HEAVY PCPN IN THE REGION...WITH THE BEST
CHANCE FOR HEAVY SNOW OVER THE SE HALF OF UPPER MI. EXPECT A SHARP
NW EDGE OF THE PCPN BAND DUE TO STRONG DESCENDING FGEN CIRCULATION
BRANCH WHICH REDUCES CONFIDENCE IN PCPN AMOUNTS THROUGH CNTRL UPPER
MI. QPF VALUES IN THE 0.30 TO 0.60 INCH RANGE WITH SNOW/WATER RATIO
VALUES NEAR 16/1 SUPPORTS GENERALLY 4 TO 8 INCH SYNOPTIC
SNOW...GREATEST OVER THE FAR S AND EAST. LAKE ENHANCED SNOW WILL
GENERALLY BE LIGHT EARLY WED WITH LOW INVERSION HEIGHTS NEAR 4K FT
AND 850 MB TEMPS ONLY NEAR -10C BUT BY WED AFTERNOON SNOWFALL RATES
OVER N CNTRL AND FAR WEST NEAR IWD SHOULD INCREASE AS 850 MB TEMPS
FALL TO NEAR -16C. ALTHOUGH UPSLOPE FLOW SHOULD ENHANCE SNOWFALL
RATES...CYCLONIC 350 FLOW MAY ALSO LEAD TO GREATER AMOUNTS NEAR THE
SHORE WED AFTERNOON.
FCST CONFIDENCE WAS HIGH ENOUGH TO UPGRADE WATCHES TO WARNINGS OVER
THE EAST HALF BUT WITH AMOUNTS ONLY IN THE 2 TO 5 INCH RANGE OVER
MARQUETTE AND DICKINSON COUNTIES THROUGH WED AND PROXIMITY TO THE
EDGE OF THE SYNOPTIC PCPN...AN ADVY WAS ISSUED.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 446 PM EST TUE JAN 29 2013
INITIAL PART OF THE LONG TERM FORECAST IS HIGHLY DEPENDENT ON THE
TRACK OF THE SHORTWAVE RIDING UP THE UPPER TROUGH OVER THE CENTRAL
CONUS AND THE ASSOCIATED LOW DEVELOPING IN NORTHERN LOWER MI AND
THEN SHIFTING NORTHEAST INTO QUEBEC ON WEDNESDAY NIGHT. THE SHORT
TERM DISCUSSION COVERS MUCH OF THE DETAILS WITH THIS SYSTEM AND THE
MAIN FEATURE TO CAPTURE IN THE LONG TERM WITH THIS SYSTEM IS THE
DIMINISHING TREND IN THE POPS/QPF OVER THE EASTERN CWA.
BEHIND THIS FEATURE...EXPECT COLD AIR TO SURGE SOUTHEAST OVER THE
UPPER GREAT LAKES REGION AND REMAIN INTO THE WEEKEND. THIS COLD
AIR...H850 TEMPS IN THE LOW -20S CELSIUS...MOVING ACROSS THE
RELATIVELY WARM LAKE SUPERIOR WATERS WILL LEAD TO PERSISTENT LAKE
EFFECT. AMOUNTS AND LOCATIONS WILL LARGELY DEPEND ON WIND DIRECTION
AND DEEPER MOISTURE DURING THIS PERIOD.
FOR WEDNESDAY NIGHT...LAKE EFFECT WILL BE INCREASING IN INTENSITY
OVER THE WEST THROUGH THE NIGHT DUE TO INCREASING COLD AIR AND
DEEPER MOISTURE ARRIVING FROM THE NORTHWEST. THIS WILL PUSH
INVERSION HEIGHTS TOWARDS 10KFT OVER THE WITH WESTERN AREAS AND
WITH DELTA-T VALUES AROUND 23...LAKE INDUCED CAPE VALUES RISE
TOWARDS 500-700 J/KG. EXPECT THE HIGHEST AMOUNTS...2-6 INCHES...IN
THE NORTH-NORTHWEST WIND FAVORED LOCATIONS. OVER THE
EAST...FORECAST IS A LITTLE MORE UNCERTAIN DUE TO THE SYSTEM...BUT
THEY TOO SHOULD TRANSITION TO LAKE EFFECT. WITH MOISTURE HELP FROM
THE SYSTEM...SNOW AMOUNTS WILL BE HIGHER THERE ESPECIALLY IN THE
LOCATIONS FAVORED BY NORTH-NORTHWEST WINDS. THE HIGHEST AMOUNTS WILL
LIKELY OCCUR THROUGH THE NIGHT OVER THE WESTERN PORTIONS OF ALGER
COUNTY...WHERE COASTAL EFFECTS FROM NORTHERN MARQUETTE COUNTY WILL
LIKELY INCREASE CONVERGENCE THERE AND THUS SNOWFALL AMOUNTS. HAVE
TRENDED POPS TOWARDS THIS IDEA FOR THE WEDNESDAY NIGHT PERIOD.
WITH THE COLD AIR CONTINING TO FLOW OVER THE AREA ON
THURSDAY...MULTI-BAND LAKE EFFECT WILL BE AIDED BY THE INCREASED MID
LEVEL MOISTURE MOVING OVER THE AREA BEHIND A SHORTWAVE DROPPING
THROUGH THE UPPER/MID MISSISSIPPI VALLEY ON THURSDAY. THIS WILL LEAD
TO INVERSION HEIGHTS IN THE 7-10KFT RANGE OVER THE AREA...WITH THE
HIGHEST VALUES OVER THE EAST. THE MAIN DETERMINING FACTOR FOR SNOW
AMOUNTS IN THE NORTHWEST WIND FAVORED LOCATIONS ON THURSDAY WILL BE
WHEN THE DGZ FALLS BELOW OR TO THE BOTTOM OF THE CLOUD LAYER. THIS
WILL OCCUR FIRST OVER THE WEST AND THEN OVER THE EAST LATE IN THE
DAY. THIS WILL LEAD TO A TRANSITION TO LOWER SNOW RATIOS WITH THE
TRANSITION TO MORE COLUMNS THAT IS USUALLY SEEN IN COLD/ARCTIC AIR
MASSES. WITH THE WINDS BACKING TO MORE OF A NORTHWEST WIND
DIRECTION THROUGH DAY...WOULD EXPECT THERE TO BE A COUPLE ENHANCED
LOCATIONS DUE TO INCREASED CONVERGENCE. AT THIS TIME...WOULD EXPECT
IT TO BE OVER GOGEBIC/ONTONAGON AND ALGER COUNTIES.
HIGH PRESSURE SLIDING SOUTHEAST FROM THE DAKOTAS ON THURSDAY NIGHT
WILL LEAD TO BACKING WINDS TO THE WEST OVER THE WESTERN LAKE AND
WEST-NORTHWEST OVER THE EAST. THIS WILL CONTINUE INTO FRIDAY AS THE
HIGH MOVES INTO THE MID MISSISSIPPI VALLEY AND LEADS TO WEST TO
WEST-SOUTHWEST WINDS. THESE WINDS WILL BE AIDED BY A WEAK LOW
DEVELOPING OVER EASTERN LAKE SUPERIOR. COLD AIR IS STILL IN THE
LOWER -20S CELSIUS DURING THE PERIOD...SO THE LAKE EFFECT WILL BE
ONGOING. BUT...WITH THE HIGH REDUCING THE MOISTURE ABOVE H850 AND
INCREASING THE SUBSIDENCE INVERSION EXPECT THERE TO BE A GRADUAL
DECREASE IN INTENSITY DURING THAT TIME FRAME.
DEFINITELY THINK THAT THE NORTH-NORTHWEST WIND LOCATIONS WILL NEED
LAKE EFFECT SNOW ADVISORIES DURING THIS WEDNESDAY NIGHT INTO
THURSDAY NIGHT PERIOD. WARNINGS ARE A LITTLE MORE UNCERTAIN DUE TO
THE LIMITED PERIODS OF THE BEST OMEGA WITHIN THE DGZ. OUT OF ALL OF
THE LOCATIONS...WOULD THINK THAT ALGER COUNTY WOULD HAVE THE BEST
OPPORTUNITY OF SEEING WARNING SNOWFALL AMOUNTS. OPTED TO GO AHEAD
AND ISSUE THE LAKE EFFECT SNOW ADVISORY FOR GOGEBIC/ONTONAGON
COUNTIES AND THE REST OF THE FAVORED AREAS WILL NEEDED TO BE ADDED
IN THE NEXT 12-24HRS.
HEADING INTO THE WEEKEND...THE COLDER AIR WILL BEGIN TO LOSE IT/S
GRIP ON THE AREA AS THE UPPER TROUGH SHIFTS TO THE EAST AND AREA
COMES UNDER NORTHWEST FLOW ALOFT. THESE PERIODS COME DOWN TO
TIMING/LOCATING SHORTWAVES MOVING THROUGH THE FLOW AND HAVE TRIED
TO FOLLOW A GENERAL CONSENSUS FOR TIMING THESE WAVES. FIRST ONE
LOOKS TO MOVE THROUGH THE AREA ON SATURDAY NIGHT AND AGAIN ON
SUNDAY NIGHT INTO MONDAY. BETWEEN THOSE TWO PERIODS...THERE SHOULD
BE ENOUGH COLD AIR TO SUPPORT LAKE EFFECT SNOW IN AREAS FAVORED BY
NORTHWEST WINDS.
WITH THE COLD AIR SPILLING INTO THE AREA...A COOLING TREND IS
EXPECTED FOR THE SECOND HALF OF THE WORK WEEK. FRIDAY CONTINUES TO
LOOK LIKE THE COLDEST DAY OVER THE NEXT 7 DAYS...WITH HIGHS OVER THE
WEST STRUGGLING TO RISE ABOVE 0 DEGREES. THIS COLD AIR WILL CAUSE
WIND CHILL VALUES TO APPROACH -25 ON ON THURSDAY NIGHT INTO
FRIDAY MORNING AND AGAIN FRIDAY NIGHT INTO SATURDAY MORNING OVER THE
INTERIOR WEST HALF OF UPPER MICHIGAN. TEMPERATURES WILL THEN WARM
BACK TO MORE NORMAL VALUES BY THE FIRST PART OF NEXT WEEK.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 551 PM EST TUE JAN 29 2013
IFR/LOW MVFR CIGS WILL PERSIST AT IWD AND CMX OVERNIGHT. LIFR CIGS
WILL REMAIN AT SAW OVERNIGHT AS NRLY UPSLOPE WINDS CONTINUE. LIGHT
SNOW WILL SPREAD INTO MAINLY CNTRL AND EAST UPPER MI WED MORNING
WITH IFR VSBY EXPECTED AT SAW. SOME LAKE ENHANCED SNOW AT IWD SHOULD
ALSO LEAD TO IFR CONDITIONS WHILE CMX IS EXPECTED TO ONLY SEE MVFR
CIGS/VSBY.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 504 PM EST TUE JAN 29 2013
A DEEPENING LOW PRESSURE SYSTEM MOVING THROUGH LAKE HURON WEDNESDAY
AND TO THE NORTHEAST BY WEDNESDAY NIGHT WILL LIKELY BRING A PERIOD
OF N TO NW GALES TO CENTRAL AND EASTERN LAKE SUPERIOR LATE TONIGHT
INTO WEDNESDAY NIGHT. WINDS/WAVES COMBINED WITH ARCTIC AIR SETTLING
OVER THE AREA WILL RESULT IN FREEZING SPRAY...POSSIBLY HEAVY AT
TIMES LATE WEDNESDAY INTO FRIDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY FROM 3 AM TO 9 PM CST WEDNESDAY FOR
MIZ011.
WINTER STORM WARNING FROM 1 AM EST /MIDNIGHT CST/ TO 10 PM EST
/9 PM CST/ WEDNESDAY FOR MIZ012>014.
WINTER STORM WARNING FROM 4 AM WEDNESDAY TO 7 AM EST THURSDAY
FOR MIZ006-007-085.
LAKE EFFECT SNOW ADVISORY FROM 7 AM EST /6 AM CST/ WEDNESDAY TO
7 AM EST /6 AM CST/ FRIDAY FOR MIZ002-009.
WINTER WEATHER ADVISORY FROM 7 AM WEDNESDAY TO 1 AM EST THURSDAY
FOR MIZ005.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING FROM 7 PM WEDNESDAY TO 7 AM EST
FRIDAY FOR LSZ265>267.
GALE WARNING FROM 10 AM WEDNESDAY TO 4 AM EST THURSDAY FOR
LSZ267.
GALE WARNING FROM 5 AM WEDNESDAY TO 4 AM EST THURSDAY FOR
LSZ264>266.
HEAVY FREEZING SPRAY WARNING FROM 1 PM EST /NOON CST/ WEDNESDAY
TO 7 AM EST /6 AM CST/ FRIDAY FOR LSZ162-263-264.
GALE WARNING FROM 5 AM TO 10 PM EST WEDNESDAY FOR LSZ263.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...SRF
AVIATION...07
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
505 PM EST TUE JAN 29 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 504 PM EST TUE JAN 29 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH FROM
NE MANITOBA THROUGH THE PLAINS INTO NEW MEXICO. WEAK SHRTWVS
EMBEDDED IN THE SW FLOW FROM THE SRN PLAINS INTO THE GREAT LAKES
SUPPORTED AREAS OF SHRA/TSRA NEAR A SFC FRONT EXTENDING FROM NE WI
THROUGH CNTRL MO AND INTO CNTRL OK. THE MAIN SHRTWV WAS REMAINED
NEAR THE BASE OF THE TROUGH...MOVING TOWARD THE TX/OK PANHANDLE.
PCPN HAD DIMINISHED OVER UPPER MICHIGAN WITH MAINLY SOME SCT LIGHT
SHOWERS MOVING THROUGH FAR SRN UPPER MI. WEST WINDS AND SLIGHTLY
DRIER AIR BEHIND A TROUGH SLIDING TO NEAR P53-ISQ HAS BROUGHT
IMPROVED VISIBILITIES THROUGH THE CNTRL AND WEST CWA.
ALTHOUGH THE 12Z ECMWF WAS A BIT SLOWER THAN THE 12Z GFS...THE MODELS
WERE IN RELATIVELY GOOD AGREEMENT WITH REGARD TO OVERALL PCPN/SNOW
POTENTIAL ACROSS THE CWA. ALTHOUGH THE 12Z NAM HAD SHIFTED THE
HEAVIER QPF AXIS WELL TO THE EAST...THE 18Z RUN HAS COME BACK INTO
BETTER AGREEMENT WITH THE GLOBAL MODELS. MODELS DIFFICULTY IN
HANDLING THE CONVECTION AND HEAVY RAIN NEAR THE FRONT MAY ACCOUNT
FOR A PORTION OF THE INCONSISTENCY AND VARIABILITY AND STILL LEADS
GREATER THAN USUAL UNCERTAINTY. ALTHOUGH THERE IS MODERATE
CONFIDENCE WITH THE MULTI-MODEL BLEND OF THE GFS/ECMWF/NAM/REG-GEM
USED FOR QPF...TIMING OF THE HEAVIER PCPN ONSET MAY BE A BIT DELAYED
GIVEN ECMWF/NAM TRENDS.
THE STRONGEST DYNAMICS ARE EXPECTED TO DEVELOP BTWN 12Z-18Z/WED AS
THE NM SHRTWV LIFTS TOWARD THE GREAT LAKES. A COUPLED UPPER LEVEL
JET STRUCTURE AND RESULTING STRONG 800-600 MB FGEN WILL SUPPORT A
PERIOD OF MODERATE TO HEAVY PCPN IN THE REGION...WITH THE BEST
CHANCE FOR HEAVY SNOW OVER THE SE HALF OF UPPER MI. EXPECT A SHARP
NW EDGE OF THE PCPN BAND DUE TO STRONG DESCENDING FGEN CIRCULATION
BRANCH WHICH REDUCES CONFIDENCE IN PCPN AMOUNTS THROUGH CNTRL UPPER
MI. QPF VALUES IN THE 0.30 TO 0.60 INCH RANGE WITH SNOW/WATER RATIO
VALUES NEAR 16/1 SUPPORTS GENERALLY 4 TO 8 INCH SYNOPTIC
SNOW...GREATEST OVER THE FAR S AND EAST. LAKE ENHANCED SNOW WILL
GENERALLY BE LIGHT EARLY WED WITH LOW INVERSION HEIGHTS NEAR 4K FT
AND 850 MB TEMPS ONLY NEAR -10C BUT BY WED AFTERNOON SNOWFALL RATES
OVER N CNTRL AND FAR WEST NEAR IWD SHOULD INCREASE AS 850 MB TEMPS
FALL TO NEAR -16C. ALTHOUGH UPSLOPE FLOW SHOULD ENHANCE SNOWFALL
RATES...CYCLONIC 350 FLOW MAY ALSO LEAD TO GREATER AMOUNTS NEAR THE
SHORE WED AFTERNOON.
FCST CONFIDENCE WAS HIGH ENOUGH TO UPGRADE WATCHES TO WARNINGS OVER
THE EAST HALF BUT WITH AMOUNTS ONLY IN THE 2 TO 5 INCH RANGE OVER
MARQUETTE AND DICKINSON COUNTIES THROUGH WED AND PROXIMITY TO THE
EDGE OF THE SYNOPTIC PCPN...AN ADVY WAS ISSUED.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 446 PM EST TUE JAN 29 2013
INITIAL PART OF THE LONG TERM FORECAST IS HIGHLY DEPENDENT ON THE
TRACK OF THE SHORTWAVE RIDING UP THE UPPER TROUGH OVER THE CENTRAL
CONUS AND THE ASSOCIATED LOW DEVELOPING IN NORTHERN LOWER MI AND
THEN SHIFTING NORTHEAST INTO QUEBEC ON WEDNESDAY NIGHT. THE SHORT
TERM DISCUSSION COVERS MUCH OF THE DETAILS WITH THIS SYSTEM AND THE
MAIN FEATURE TO CAPTURE IN THE LONG TERM WITH THIS SYSTEM IS THE
DIMINISHING TREND IN THE POPS/QPF OVER THE EASTERN CWA.
BEHIND THIS FEATURE...EXPECT COLD AIR TO SURGE SOUTHEAST OVER THE
UPPER GREAT LAKES REGION AND REMAIN INTO THE WEEKEND. THIS COLD
AIR...H850 TEMPS IN THE LOW -20S CELSIUS...MOVING ACROSS THE
RELATIVELY WARM LAKE SUPERIOR WATERS WILL LEAD TO PERSISTENT LAKE
EFFECT. AMOUNTS AND LOCATIONS WILL LARGELY DEPEND ON WIND DIRECTION
AND DEEPER MOISTURE DURING THIS PERIOD.
FOR WEDNESDAY NIGHT...LAKE EFFECT WILL BE INCREASING IN INTENSITY
OVER THE WEST THROUGH THE NIGHT DUE TO INCREASING COLD AIR AND
DEEPER MOISTURE ARRIVING FROM THE NORTHWEST. THIS WILL PUSH
INVERSION HEIGHTS TOWARDS 10KFT OVER THE WITH WESTERN AREAS AND
WITH DELTA-T VALUES AROUND 23...LAKE INDUCED CAPE VALUES RISE
TOWARDS 500-700 J/KG. EXPECT THE HIGHEST AMOUNTS...2-6 INCHES...IN
THE NORTH-NORTHWEST WIND FAVORED LOCATIONS. OVER THE
EAST...FORECAST IS A LITTLE MORE UNCERTAIN DUE TO THE SYSTEM...BUT
THEY TOO SHOULD TRANSITION TO LAKE EFFECT. WITH MOISTURE HELP FROM
THE SYSTEM...SNOW AMOUNTS WILL BE HIGHER THERE ESPECIALLY IN THE
LOCATIONS FAVORED BY NORTH-NORTHWEST WINDS. THE HIGHEST AMOUNTS WILL
LIKELY OCCUR THROUGH THE NIGHT OVER THE WESTERN PORTIONS OF ALGER
COUNTY...WHERE COASTAL EFFECTS FROM NORTHERN MARQUETTE COUNTY WILL
LIKELY INCREASE CONVERGENCE THERE AND THUS SNOWFALL AMOUNTS. HAVE
TRENDED POPS TOWARDS THIS IDEA FOR THE WEDNESDAY NIGHT PERIOD.
WITH THE COLD AIR CONTINING TO FLOW OVER THE AREA ON
THURSDAY...MULTI-BAND LAKE EFFECT WILL BE AIDED BY THE INCREASED MID
LEVEL MOISTURE MOVING OVER THE AREA BEHIND A SHORTWAVE DROPPING
THROUGH THE UPPER/MID MISSISSIPPI VALLEY ON THURSDAY. THIS WILL LEAD
TO INVERSION HEIGHTS IN THE 7-10KFT RANGE OVER THE AREA...WITH THE
HIGHEST VALUES OVER THE EAST. THE MAIN DETERMINING FACTOR FOR SNOW
AMOUNTS IN THE NORTHWEST WIND FAVORED LOCATIONS ON THURSDAY WILL BE
WHEN THE DGZ FALLS BELOW OR TO THE BOTTOM OF THE CLOUD LAYER. THIS
WILL OCCUR FIRST OVER THE WEST AND THEN OVER THE EAST LATE IN THE
DAY. THIS WILL LEAD TO A TRANSITION TO LOWER SNOW RATIOS WITH THE
TRANSITION TO MORE COLUMNS THAT IS USUALLY SEEN IN COLD/ARCTIC AIR
MASSES. WITH THE WINDS BACKING TO MORE OF A NORTHWEST WIND
DIRECTION THROUGH DAY...WOULD EXPECT THERE TO BE A COUPLE ENHANCED
LOCATIONS DUE TO INCREASED CONVERGENCE. AT THIS TIME...WOULD EXPECT
IT TO BE OVER GOGEBIC/ONTONAGON AND ALGER COUNTIES.
HIGH PRESSURE SLIDING SOUTHEAST FROM THE DAKOTAS ON THURSDAY NIGHT
WILL LEAD TO BACKING WINDS TO THE WEST OVER THE WESTERN LAKE AND
WEST-NORTHWEST OVER THE EAST. THIS WILL CONTINUE INTO FRIDAY AS THE
HIGH MOVES INTO THE MID MISSISSIPPI VALLEY AND LEADS TO WEST TO
WEST-SOUTHWEST WINDS. THESE WINDS WILL BE AIDED BY A WEAK LOW
DEVELOPING OVER EASTERN LAKE SUPERIOR. COLD AIR IS STILL IN THE
LOWER -20S CELSIUS DURING THE PERIOD...SO THE LAKE EFFECT WILL BE
ONGOING. BUT...WITH THE HIGH REDUCING THE MOISTURE ABOVE H850 AND
INCREASING THE SUBSIDENCE INVERSION EXPECT THERE TO BE A GRADUAL
DECREASE IN INTENSITY DURING THAT TIME FRAME.
DEFINITELY THINK THAT THE NORTH-NORTHWEST WIND LOCATIONS WILL NEED
LAKE EFFECT SNOW ADVISORIES DURING THIS WEDNESDAY NIGHT INTO
THURSDAY NIGHT PERIOD. WARNINGS ARE A LITTLE MORE UNCERTAIN DUE TO
THE LIMITED PERIODS OF THE BEST OMEGA WITHIN THE DGZ. OUT OF ALL OF
THE LOCATIONS...WOULD THINK THAT ALGER COUNTY WOULD HAVE THE BEST
OPPORTUNITY OF SEEING WARNING SNOWFALL AMOUNTS. OPTED TO GO AHEAD
AND ISSUE THE LAKE EFFECT SNOW ADVISORY FOR GOGEBIC/ONTONAGON
COUNTIES AND THE REST OF THE FAVORED AREAS WILL NEEDED TO BE ADDED
IN THE NEXT 12-24HRS.
HEADING INTO THE WEEKEND...THE COLDER AIR WILL BEGIN TO LOSE IT/S
GRIP ON THE AREA AS THE UPPER TROUGH SHIFTS TO THE EAST AND AREA
COMES UNDER NORTHWEST FLOW ALOFT. THESE PERIODS COME DOWN TO
TIMING/LOCATING SHORTWAVES MOVING THROUGH THE FLOW AND HAVE TRIED
TO FOLLOW A GENERAL CONSENSUS FOR TIMING THESE WAVES. FIRST ONE
LOOKS TO MOVE THROUGH THE AREA ON SATURDAY NIGHT AND AGAIN ON
SUNDAY NIGHT INTO MONDAY. BETWEEN THOSE TWO PERIODS...THERE SHOULD
BE ENOUGH COLD AIR TO SUPPORT LAKE EFFECT SNOW IN AREAS FAVORED BY
NORTHWEST WINDS.
WITH THE COLD AIR SPILLING INTO THE AREA...A COOLING TREND IS
EXPECTED FOR THE SECOND HALF OF THE WORK WEEK. FRIDAY CONTINUES TO
LOOK LIKE THE COLDEST DAY OVER THE NEXT 7 DAYS...WITH HIGHS OVER THE
WEST STRUGGLING TO RISE ABOVE 0 DEGREES. THIS COLD AIR WILL CAUSE
WIND CHILL VALUES TO APPROACH -25 ON ON THURSDAY NIGHT INTO
FRIDAY MORNING AND AGAIN FRIDAY NIGHT INTO SATURDAY MORNING OVER THE
INTERIOR WEST HALF OF UPPER MICHIGAN. TEMPERATURES WILL THEN WARM
BACK TO MORE NORMAL VALUES BY THE FIRST PART OF NEXT WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 139 PM EST TUE JAN 29 2013
MAINLY IFR CIGS ARE EXPECTED TO PERSIST AT CMX/IWD THIS AFTERNOON.
AS WINDS VEER WEST BEHIND A TROUGH THIS AFTERNOON VSBY IS EXPECTED
TO IMPROVE AT SAW EVEN THOUGH IFR CIGS WILL PERSIST. LIGHT SNOW WILL
SPREAD INTO MAINLY CNTRL AND EAST UPPER MI WED MORNING WITH IFR VSBY
EXPECTED AT SAW. SOME LAKE ENHANCED SNOW AT IWD SHOULD ALSO LEAD TO
IFR CONDITIONS WHILE CMX IS EXPECTED TO ONLY SEE MVFR CIGS/VSBY.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 504 PM EST TUE JAN 29 2013
A DEEPENING LOW PRESSURE SYSTEM MOVING THROUGH LAKE HURON WEDNESDAY
AND TO THE NORTHEAST BY WEDNESDAY NIGHT WILL LIKELY BRING A PERIOD
OF N TO NW GALES TO CENTRAL AND EASTERN LAKE SUPERIOR LATE TONIGHT
INTO WEDNESDAY NIGHT. WINDS/WAVES COMBINED WITH ARCTIC AIR SETTLING
OVER THE AREA WILL RESULT IN FREEZING SPRAY...POSSIBLY HEAVY AT
TIMES LATE WEDNESDAY INTO FRIDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY FROM 3 AM TO 9 PM CST WEDNESDAY FOR
MIZ011.
WINTER STORM WARNING FROM 1 AM EST /MIDNIGHT CST/ TO 10 PM EST
/9 PM CST/ WEDNESDAY FOR MIZ012>014.
WINTER STORM WARNING FROM 4 AM WEDNESDAY TO 7 AM EST THURSDAY
FOR MIZ006-007-085.
LAKE EFFECT SNOW ADVISORY FROM 7 AM EST /6 AM CST/ WEDNESDAY TO
7 AM EST /6 AM CST/ FRIDAY FOR MIZ002-009.
WINTER WEATHER ADVISORY FROM 7 AM WEDNESDAY TO 1 AM EST THURSDAY
FOR MIZ005.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING FROM 7 PM WEDNESDAY TO 7 AM EST
FRIDAY FOR LSZ265>267.
GALE WARNING FROM 10 AM WEDNESDAY TO 4 AM EST THURSDAY FOR
LSZ267.
GALE WARNING FROM 5 AM WEDNESDAY TO 4 AM EST THURSDAY FOR
LSZ264>266.
HEAVY FREEZING SPRAY WARNING FROM 1 PM EST /NOON CST/ WEDNESDAY
TO 7 AM EST /6 AM CST/ FRIDAY FOR LSZ162-263-264.
GALE WARNING FROM 5 AM TO 10 PM EST WEDNESDAY FOR LSZ263.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...SRF
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
349 PM EST TUE JAN 29 2013
.SYNOPSIS...
ISSUED AT 348 PM EST TUE JAN 29 2013
AREAS OF FOG WILL GIVE WAY TO HEAVY RAIN TONIGHT AS LOW PRESSURE
MOVES THROUGH. SOME FLOODING IS POSSIBLE. THE RAIN WILL MOVE EAST
ON WEDNESDAY WITH COLDER AIR MOVING IN ALONG WITH SOME RAIN
CHANGING TO SNOW. TEMPERATURES WILL CONTINUE TO FALL THROUGH
FRIDAY ALONG WITH LAKE EFFECT SNOW SHOWERS.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 348 PM EST TUE JAN 29 2013
AREAS OF PATCHY DENSE FOG WILL CONTINUE THIS EVENING ACROSS THE
NORTHERN ZONES UNTIL THE WARM FRONT LIFTS THROUGH. COVERAGE IS
VARIABLE ENOUGH TO NOT GO WITH A DENSE FOG ADVISORY BUT WILL HAVE
TO MONITOR OBS NEXT FEW HOURS.
FLOOD WATCH CONTINUES TONIGHT FOR ALL ZONES. MOST IF NOT ALL OF
THE SNOW IS GONE ACROSS THE CENTRAL AND SOUTHERN ZONES BUT SOME
SNOWMELT CONTRIBUTION REMAINS UP NORTH WHERE QPF IS EXPECTED TO BE
1 TO 2 INCHES. 12Z MODEL GUIDANCE SHIFTED NORTH WITH THE AXIS OF
HEAVIEST QPF ALTHOUGH THE HRRR HAS BEEN SHOWING THE MOST
CONVECTIVE...AND HEAVIER...RAINS FURTHER SOUTH AND EAST. SEE HYDRO
SECTION OF FORECAST FOR SPECIFICS ON RIVER FLOOD WARNINGS.
EXPECT THE HEAVIEST RAINS TO MOVE INTO WESTERN ZONES THIS EVENING
THEN MARCH STEADILY ACROSS THE FORECAST AREA OVERNIGHT...DEPARTING
THE EASTERN ZONES WEDNESDAY MORNING. THE DEFORMATION RAIN/SNOW
ZONE SHOULD BE REACHING THE NORTHWEST FORECAST AREA WEDNESDAY
MORNING. WILL HAVE TO WATCH THIS AREA FOR ACCUMULATING SNOW BY LATE
WEDNESDAY MORNING INTO THE AFTERNOON. COLD AIR ARRIVES IN THE
AFTERNOON WITH LAKE EFFECT KICKING IN WEDNESDAY NIGHT. EXPECT LAKE
EFFECT TO PENETRATE INLAND THURSDAY AND THURSDAY NIGHT WITH FLOW
GOING NORTHWEST TO WEST.
.LONG TERM...(FRIDAY THROUGH TUESDAY)
ISSUED AT 348 PM EST TUE JAN 29 2013
THE ECMWF AND GFS ARE IN PRETTY GOOD AGREEMENT THROUGH THE WEEKEND.
BOTH MODELS SHOW THE DEEP UPPER TROUGH MOVING EAST AWAY FROM THE
AREA AND TAKING THE CORE OF THE COLD AIR WITH IT. THE DGZ IS ALREADY
GOING TO BE VERY LOW FRIDAY AND WITH THE COLD AIR MOVING AWAY WE/LL
SEE THE EASTERN EDGE OF THE LAKE EFFECT SNOW SHOWERS RETREATING
TOWARD THE LAKE SHORE AND THEN DIMINISHING FRIDAY NIGHT AND
SATURDAY.
THE NEXT CHC FOR SNOW AFTER THAT WILL BE MONDAY WHEN A CLIPPER
MOVES TOWARD NRN LWR. THE GFS TAKES A MORE SRN TRACK AND WOULD
GIVE US MORE SNOW. HOWEVER...WE HAVE NOT HAD MANY CLIPPERS THAT
HAVE CROSSED THE CWA THIS YEAR AND SO WE/LL LEAN MORE TOWARD THE
FARTHER NORTH ECMWF. TEMPS WILL WARM FROM HIGHS IN THE MID TEENS
FRIDAY TO MID 30S BY MONDAY BEFORE COOLING OFF TUESDAY AFTER THE
CLIPPER DRAGS A COLD FRONT THROUGH.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1252 PM EST TUE JAN 29 2013
WIDESPREAD IFR/LIFR CONDITIONS EXPECTED THROUGH THE PERIOD. WE/LL
SEE CONSIDERABLE RAIN TONIGHT AHEAD OF THE ARCTIC FRONT. TSRA ALSO
EXPECTED FROM AROUND SUNSET THROUGH MUCH OF THE OVERNIGHT HOURS.
IT/S POSSIBLE THAT SNOW WILL MIX IN WITH THE RAIN AT KMKG MID TO
LATE MORNING WEDNESDAY.
&&
.MARINE...
ISSUED AT 348 PM EST TUE JAN 29 2013
WILL HOIST A SMALL CRAFT ADVISORY FOR TONIGHT THROUGH THURSDAY
MORNING. THIS MAY HAVE TO BE UPGRADED TO A GALE WARNING FOR
WEDNESDAY LATER ON...BUT FOR NOW IT APPEARED MARGINAL ENOUGH TO
JUST GO WITH A SCA THROUGH THE PERIOD.
&&
.HYDROLOGY...
ISSUED AT 348 PM EST TUE JAN 29 2013
SCOTTVILLE ON THE PERE MARQUETTE IS FORECAST TO FLOOD...BUT OTHER
RIVER POINTS ARE CURRENTLY EXPECTED TO STAY BELOW FLOOD STAGE.
WILL HAVE TO WATCH THE PROGRESSION OF RAIN AND SNOW MELT THIS
EVENING AND SOME OTHER SITES MAY BE ADDED TO FLOOD WARNINGS AT
SOME POINT TONIGHT.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...FLOOD WATCH FROM 7 PM EST THIS EVENING THROUGH WEDNESDAY
AFTERNOON FOR MIZ037>040-043>046-050>052-056>059-064>067-
071>074.
LM...SMALL CRAFT ADVISORY FROM 1 AM WEDNESDAY TO 7 AM EST THURSDAY
FOR LMZ844>849.
&&
$$
SYNOPSIS...OSTUNO
SHORT TERM...OSTUNO
LONG TERM...93
AVIATION...93
HYDROLOGY...OSTUNO
MARINE...OSTUNO
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1139 PM CST MON JAN 28 2013
.UPDATE...
UPDATED FOR 06Z AVIATION DISCUSSION.
&&
.PREV DISCUSSION.../ISSUED AT 413 PM CST MON JAN 28 2013/
FIRST THE HEADLINES. STARTING WITH THE HRRR/RUC THEN THE REST OF
THE 12Z RUNS...MODELS BEGAN TO SHIFT HEAVY SNOW BAND FOR TONIGHT
FARTHER NORTHWEST...KEEPING THE BULK OF THE SNOW NW OF THE MPX
CWA. MAY STILL GET A COUPLE INCHES OF SNOW IN THE FAR NW CORNERS
OF TODD...DOUGLAS...AND STEVENS COUNTIES...SO WITH THAT ALONG WITH
MATCHING UP WITH WHAT NEIGHBORS WERE DOING...ISSUED A WINTER
WEATHER ADVISORY FOR THOSE THREE COUNTIES. AT THE OTHER END OF THE
CWA HAVE A FREEZING RAIN ADVISORY FOR NE 3 COUNTIES IN WI. NOT
THRILLED WITH DOING THIS ADVISORY...BUT TO MATCH UP WITH
NEIGHBORING OFFICES...INCLUDED THESE COUNTIES IN A FREEZING RAIN
ADVY. EVERYWHERE ELSE...DENSE FOG IS LOOKING LIKE ALL BUT A
CERTAINTY FOR TONIGHT...SO A NEW DENSE FOG ADVISORY HAS BEEN
HOISTED.
UPPER WAVE RESPONSIBLE FOR ALL OF THIS HEADLINE FUN IS A DEEP
THROUGH THAT CAN BE SEEN ACROSS THE ERN ROCKIES THIS
AFTERNOON...AND WILL SLIDE ACROSS THE CENTER OF THE CONUS THROUGH
WEDNESDAY. AT THIS SFC...A 996 MB LOW AT 3 PM WAS CENTERED OVER
ERN CO. FAIRLY GOOD CONSENSUS AMONGST GUIDANCE ON THIS LOW MOVING
TO NEAR THE SE TIP OF MN BY TUESDAY MORNING...THEN OFF TO ERN LAKE
SUPERIOR BY THE TUE AFTERNOON. SEEING AN IMPRESSIVE WARM FRONT
MOVING NORTH ACROSS THE PLAINS WITH THIS LOW...WITH TEMPS IN THE
LOWER 70S AND DEWPS IN THE LOWER 50S UP TO ALMOST THE IA BORDER.
FOR THE WEATHER TONIGHT...LEANED MOST TOWARD THE 12Z NAM FOR
TIMING PRECIP IN AND ACROSS THE AREA AS THIS IS A GOOD
CONTINUATION OF WHAT THE RAP HAS BEEN SHOWING. RIGHT NOW...SEEING
IMPRESSIVE FGEN BAND SETTING UP ACROSS NE SODAK INTO NW MN...AND
LOOKING AT RAP H7-H6 FGEN FORECAST...SHOULD SEE AN INTENSE BAND OF
SNOW SET UP FROM NEAR ABERDEEN UP TO DETROIT LAKES. WITHIN THE
CENTER OF THE BAND SHOULD SEE A GOOD 4 TO 6 INCHES OF SNOW. FOR
THE MPX AREA...FAR NW CORNERS OF OUR FAR NW COUNTIES SHOULD GET IN
ON THE SRN FRINGE OF THIS BAND...WITH A COUPLE OF INCHES OF SNOW
BEING POSSIBLE. FOR SNOW POTENTIAL IN THE WEST...WILL HAVE TO WHAT
HAPPENS WITH A SECONDARY SHORT WAVE THAT SNEAKS UP WEST OF THE SFC
LOW LATE TONIGHT INTO TUESDAY MORNING. THE GEM WAS THE MOST
BULLISH WITH THIS WAVE...BRING A QUICK 2-3 INCHES OF SNOW TO WRN
MN. DID NOT PUT MUCH STOCK IN IT...BUT NOTICING THAT TOWARD THE
END OF RECENT RAP RUNS IT HAS BEEN SHOWING THIS SECONDARY BAND
SNEAKING IN AS WELL...SO WILL NEED TO WATCH THIS OVERNIGHT TO SEE
IF THE WINTER WEATHER ADVISORY NEEDS TO BE PULLED SOUTH.
OUTSIDE OF THE NW CWA...SOUNDINGS SHOW WHATEVER HAPPENING TONIGHT
TO BE DRIZZLE OR LIGHT RAIN...WITH ATMO ABOVE ABOUT H8 BEING DRY...
AND LITTLE OR NO SATURATION BEING SEEN IN THE DENDRITIC GROWTH
ZONE. SHOULD SEE DZ/RA RAPIDLY SPREAD NORTH AFTER 00Z AS STRONG
LOW LEVEL THETA-E ADVECTION WORKS IN. AT THE NOSE OF THE LLJ...THE
RAP IS EVEN INDICATING SOME THUNDER BEING POSSIBLE IN THE EAU AREA
AROUND MIDNIGHT AS BEST LIS DROP TO AROUND -1. 18Z HRRR
REFLECTIVITY FORECAST LOOKS CONVECTIVE IN THIS AREA AS WELL. OF
COURSE WITH ALL OF THIS PRECIP THE KEY WILL BE SFC TEMPS. THE
ENTIRE CWA CURRENTLY SITS BETWEEN 32 AND 36 AND WITH CONTINUED
SOUTHEAST FLOW THROUGH THE NIGHT...DO NOT EXPECT THESE TO CHANGE
MUCH...IN FACT...TEMPERATURES MAY CONTINUE TO RISE RIGHT THROUGH
THE NIGHT ACROSS THE SE CWA. BECAUSE OF THESE MILD
TEMPERATURES...WAS NOT TOO INCLINED TO ISSUE A FREEZING RAIN ADVY
WITH IT BEING QUESTIONABLE IF TEMPS FALL BELOW FREEZING. IN
ADDITION...WITH P-TYPE MAINLY BEING DZ...NOT EXPECTING MANY IMPACTS
WITH DZ AND TEMPS IN THE 30S WITH ALREADY WET SFCS IN PLACE DUE TO
MELTING TODAY. MAKE IT DRY WITH TEMPS IN THE 20S...AND IT WOULD BE
A DIFFERENT STORY...BUT THAT IS NOT WHAT WE ARE DEALING WITH.
WHERE THE HIGHEST POTENTIAL FOR MEANINGFUL FZRA EXISTS WOULD BE IN
THE FAR NE CWA...WHERE THERE WILL BE THE POTENTIAL FOR RAIN THIS
EVENING ON THE NOSE OF THE LLJ.
AS FOR THE FOG...THERE IS NOTHING BUT A SEA OF DENSE FOG FROM SRN
MN DOWN ACROSS IA AND ERN NEB. THIS WILL ADVECT RIGHT BACK NORTH
THIS EVENING...WITH WIDESPREAD FOG EXPECTED AGAIN...AS SEEN WITH
THE GRIDDED LAMP...HRRR...AND WRF-NMM. FOG SHOULD IMPROVE LATE
TONIGHT FROM WEST TO EAST AS AN INVERTED TROUGH/COLD FRONT WORKS
ACROSS MN. FOR SIMPLICITY SAKE...RAN THE FOG ADVY THROUGH 10 AM
TUESDAY MORNING EVERYWHERE...BUT CONDITIONS SHOULD IMPROVE
EARLIER THAN THAT IN WRN MN.
PRECIPITATION SHOULD MOSTLY COME TO AN END BY TUESDAY AFTERNOON
ACROSS THE AREA AS DRY ARCTIC HIGH BEGINS BUILDING IN. STILL SOME
DISAGREEMENT WITH PRECIP POTENTIAL TUESDAY NIGHT AS ANOTHER SFC
LOW RIPPLES NORTH ALONG THE FRONT FROM THE TULSA AREA UP TO MID
MICHIGAN. HUNG SOME CHANCE POPS BACK ACROSS ERN AREA TO ACCOUNT
FOR THE OFF CHANCE THAT SOME SNOW DEVELOPS WEST OF THE LOW. NOT ALL
THAT EXCITED ABOUT SNOW POTENTIAL ON THE BACK SIDE OF THIS SYSTEM
TUESDAY NIGHT INTO WEDNESDAY DUE TO THE FACT THAT UPPER FLOW WILL
BE NEARLY PARALLEL TO THE FRONTAL BOUNDARY. THIS WILL LIKELY KEEP
A COLD CONVEYOR BELT FROM DEVELOPING TO THE NORTH AND NORTHWEST OF
THE LOW AS IT WORKS UP ALONG THE FRONT...WITH MOST ACTIVITY STAYING
NEAR THE FRONT...AND NOT WORKING BACK TOWARD THE EAU AREA.
OF COURSE THE BIG STORY FOR WEDNESDAY THROUGH FRIDAY WILL BE THE
ARRIVAL OF ANOTHER SIGNIFICANT CHUNK OF ARCTIC AIR. TEMPERATURES
WILL BE NEARLY STEADY OR FALLING MUCH OF WEDNESDAY AFTERNOON...AND
BY WEDNESDAY NIGHT...THE COMBO OF TEMPS FALLING TO BELOW ZERO ON
15 TO 25 MPH NW WINDS WILL BRING BACK THE NEED FOR WIND CHILL
ADVISORIES FROM WEDNESDAY NIGHT RIGHT INTO FRIDAY MORNING.
AFTER FRIDAY...TEMPERATURES WILL MODERATE BACK CLOSER TO AND EVEN A
LITTLE ABOVE NORMAL BY THE END OF THE WEEKEND. STILL SEEING THE
POTENTIAL FOR A CLIPPER FRI NIGHT/SATURDAY ON THE ECMWF/GEM...WITH
A COUPLE OF INCHES OF SNOW BEING POSSIBLE ALONG AND NORTH OF I-94.
&&
.AVIATION.../06Z TAF ISSUANCE/
IFR OR LIFR CONDITIONS STILL EXPECTED THROUGH THIS MORNING. THE
MAIN FORECAST UNCERTAINTIES CONTINUE TO BE PRECIPITATION TYPE.
MOST STATIONS ARE AT OR SLIGHTLY ABOVE FREEZING WHICH SHOULD
CONTINUE FOR MUCH OF THE NIGHT IN THE LIGHT SOUTHEAST FLOW. NOT
OVERLY CONCERNED WITH FZDZ OR FZRA DUE TO THE MOIST AIRMASS WHICH
LIMITS ICE ACCRETION AT THESE MARGINAL TEMPERATURES. WITH TIME...A
BAND OF SNOW IS EXPECTED TO DEVELOP ACROSS WEST CENTRAL MN AND THE
BULK OF IT SHOULD REMAIN JUST WEST OF AXN. AS LOW PRESSURE TRACKS
NORTHEAST INTO WISCONSIN TUESDAY MORNING...DRIER AIR WILL BEGIN TO
WORK IN WITH IMPROVING CONDITIONS. THIS COULD ALSO BRING A BETTER
CHANCE FOR -SN OR FZDZ FURTHER EAST.
KMSP...LIFR CONDITIONS EXPECTED THROUG THIS MORNING WITH A GRADUAL
IMPROVEMENT TO MVFR TUESDAY AFTERNOON. PRECIP SHOULD REMAIN IN
LIQUID FORM...BUT WILL NEED TO WATCH TEMPERATURES CLOSELY FOR
POTENTIAL FOR FZDZ LATE TONIGHT. BETTER CHANCE OF SUCH PRECIP WILL
ARRIVE MID MORNING TUESDAY AS COLDER AND DRIER AIR BEGINS TO WORK
IN FROM THE NORTH/NORTHWEST.
/OUTLOOK FOR KMSP/
WED...MVFR WITH POSSIBLE --SN. WIND NW 15-20G30KT.
THU...VFR WITH POSSIBLE MVFR CIGS. WIND NW 10-15G20KT.
FRI...VFR WITH POSSIBLE MVFR CIGS. LGT/VRB WIND.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...DENSE FOG ADVISORY UNTIL 9 AM CST TUESDAY FOR ANOKA-BENTON-BLUE
EARTH-BROWN-CARVER-CHIPPEWA-CHISAGO-DAKOTA-FARIBAULT-
FREEBORN-GOODHUE-HENNEPIN-ISANTI-KANABEC-KANDIYOHI-LAC QUI
PARLE-LE SUEUR-MARTIN-MCLEOD-MEEKER-MILLE LACS-MORRISON-
NICOLLET-POPE-RAMSEY-REDWOOD-RENVILLE-RICE-SCOTT-SHERBURNE-
SIBLEY-STEARNS-STEELE-SWIFT-WASECA-WASHINGTON-WATONWAN-
WRIGHT-YELLOW MEDICINE.
WINTER WEATHER ADVISORY UNTIL 6 AM CST TUESDAY FOR DOUGLAS-
STEVENS-TODD.
WI...DENSE FOG ADVISORY UNTIL 9 AM CST TUESDAY FOR DUNN-EAU CLAIRE-
PEPIN-PIERCE-POLK-ST. CROIX.
FREEZING RAIN ADVISORY UNTIL 9 AM CST TUESDAY FOR BARRON-
CHIPPEWA-RUSK.
&&
$$
MPG/CLF
AREA FORECAST DISCUSSION
NWS HASTINGS NE
358 PM CST TUE JAN 29 2013
.SHORT TERM...TONIGHT AND WEDNESDAY.
HIGHLY AMPLIFIED MEAN TROUGH IS HEADING EAST WITH THE AXIS CROSSING
INTO THE HIGH PLAINS. STRONG JET AHEAD OF THIS AXIS WITH STIFF
MID-LEVEL FRONTOGENETIC FORCING PREDICTED TO RAMP UP THIS EVENING.
THIS IS SUPPORTED BY THE NAM...HRRR...ECMWF...AND GFS...ALL PLACING
DECENT QPF AMOUNTS IN THE EAST/SOUTHEAST PART OF THE CWA AT THE VERY
LEAST.
THIS AGREEMENT AMONG MODELS HAS LED ME TO INCREASE CHANCES OF
PRECIPITATION EVEN MORE. SOUNDINGS INDICATE THAT THIS WILL BE A SNOW
EVENT AND HAVE GONE WITH ONLY SNOW AS THE PRECIPITATION TYPE...AS
OPPOSED TO MENTIONING RAIN AT ONSET. THE HRRR INDICATE4D QUITE A RAMP
UP IN QPF PRODUCTION BY EARLY AFTERNOON...WHICH PROMPTED ME TO GO
WITH AN ADVISORY FOR MOST OF OUR EASTERN CWA. I FELT INCLINED TO DO
THIS AS NORTH/NORTHWEST WIND WILL RAMP UP CONSIDERABLY TONIGHT AS
THE SURFACE PRESSURE GRADIENT INCREASES. I INCREASED WIND SPEEDS A
BIT MORE FROM THE PREVIOUS FORECAST FOR TONIGHT INTO WEDNESDAY. SNOW
SHOULD WIND DOWN FAIRLY QUICKLY AS THE TROUGH AXIS HEADS TO THE EAST
BY THE OVERNIGHT. LEFT THE SLIGHT CHANCE OF FLURRIES IN OUR
NORTHEAST FOR WEDNESDAY MORNING...BUT I DID NOTICE THE NAM PULLING
BACK A LITTLE ON STRATUS...WHICH USUALLY INDICATES A LACK OF FLURRY
POTENTIAL...BUT CLOSE ENOUGH FOR ME TO LEAVE IN FOR NOW. WIND SHOULD
REMAIN BELOW WIND ADVISORY CRITERIA FOR WEDNESDAY...ALTHOUGH OUR FAR
NORTH MAY FLIRT WITH IT...JUDGING BY PREDICTED MOMENTUM TRANSFER.
KEPT SKY COVER GENERALLY CLOUDY...ALTHOUGH THERE COULD BE SOME
BREAKS...ESPECIALLY IN THE SOUTH BY AFTERNOON. KEPT TEMPERATURES THE
SAME FOR TONIGHT AND WEDNESDAY FROM PREVIOUS FORECAST AS THEY LOOKED
LIKE THEY WERE RIGHT ON TARGET.
.LONG TERM...WEDNESDAY NIGHT THROUGH TUESDAY. MAIN FORECAST CONCERN
IN THE EXTENDED WILL BE THE TEMPERATURES.
STARTING WED EVENING...THE BIG PICTURE SHOWS THE CENTRAL U.S. IN
NORTHWEST FLOW AS THE UPPER TROUGH IS SLATED TO BE MOVING INTO THE
MIDWEST WITH RIDGING MOVING ONTO THE PACIFIC NORTHWEST COAST. AS THE
WORK WEEK ROLLS ALONG IT APPEARS WE WILL PRETTY MUCH STAY IN THIS
TYPE OF FLOW WITH OVERALL RIDGING TO THE WEST AND TROUGHING EAST.
WILL MOST LIKELY HAVE A FEW CLIPPER LIKE WAVES SLIDE THROUGH OUR
REGION UNDER THIS TYPE OF PATTERN AND THE QUESTION IS WILL THEY
BRING ANY ADDITIONAL PRECIPITATION CHANCES. BASIC ANSWER IS NO
ALTHOUGH WE DO HAVE A CHANCE OF FLURRIES MENTIONED FOR WED NIGHT AND
THURSDAY IN THE CURRENT FORECAST AND WILL GO AHEAD AND KEEP THEM IN
GIVEN SUFFICIENT MOISTURE AND COLDER TEMPERATURES NOTED IN MODEL
FORECAST SOUNDINGS. OTHERWISE WILL LEAVE THE REST OF THE FORECAST
DRY ALTHOUGH SOME LIGHT PRECIPITATION NOT TOTALLY OUT OF THE
QUESTION FOR FRIDAY.
AS FAR AS TEMPERATURES GO...IT WILL REMAIN QUITE CHILLY WED NIGHT
INTO FRIDAY MORNING AS ADDITIONAL COLD AIR SLIDES DOWN FROM THE
NORTH...ALTHOUGH THE BITTER COLD AIR SHOULD REMAIN JUST NORTHEAST OF
THE CWA. STOUT NORTHWEST WINDS ARE ALSO EXPECTED AGAIN FOR THURSDAY
AFTERNOON AS WE SIT BETWEEN 1038 MB HIGH PRESSURE OVER MONTANA/NDAK
AND LOW PRESSURE ACROSS MISSOURI AND KANSAS. FRIDAY MORNING MIGHT
BE THE COLDEST DAY OF THE WEEK DEPENDING ON WHETHER HIGH PRESSURE
DROPS RIGHT OVER THE TOP OF US OR SLIDES A LITTLE TO THE EAST IN
WHICH CASE WE MIGHT HAVE A MORE CLOUD COVER AND LIGHT SOUTHERLY
FLOW.
GOING INTO THE WEEKEND HEIGHTS BEGIN TO RISE AS WESTERN RIDGE STARTS
TO MOVE EAST AND AT THIS POINT APPEARS BOTH SAT AND SUNDAY SHOULD BE
CLOSE TO 50 DEGREES. ANOTHER WEAK FRONT IS EXPECTED TO PUSH ACROSS
SUNDAY NIGHT OR MONDAY WITH HIGH TEMPERATURES FALLING A TAD BUT
STILL ABOVE SEASONAL LEVELS.
&&
.PREV DISCUSSION... /ISSUED 1243 PM CST TUE JAN 29 2013/
AVIATION...18Z KGRI TAF. CEILINGS WILL BE TRICKY FOR THE FIRST
SEVERAL HOURS OF THE FORECAST AS CEILINGS ARE HIGHLY VARIABLE EAST
OF A BAND OF SNOW THAT HAS DEVELOPED WEST OF THE TERMINAL. SOME
SNOW IS EXPECTED TO MOVE IN THIS EVENING WITH AN INCREASE IN WIND
SPEED BEHIND A COLD FRONT. MVFR CEILINGS ARE FORECAST FOR MUCH OF
THE FORECAST. VISIBILITY IS FORECAST FOR MVFR WHEN SNOW
BEGINS...BUT THIS COULD BE TEMPORARILY LOWER IF A BAND OF HEAVIER
SNOW SETS UP...BUT THIS IS MORE LIKELY TO OCCUR TO THE SOUTHEAST.
CEILINGS SHOULD RISE TOWARD MID-MORNING WEDNESDAY...BUT WIND WILL
REMAIN RATHER BRISK FROM THE NORTHWEST.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...WINTER WEATHER ADVISORY UNTIL 1 AM CST WEDNESDAY FOR NEZ049-063-
064-076-077-086-087.
KS...WINTER WEATHER ADVISORY UNTIL 1 AM CST WEDNESDAY FOR KSZ007.
&&
$$
SHORT TERM/AVIATION...HEINLEIN
LONG TERM...EWALD
AREA FORECAST DISCUSSION
NWS BUFFALO NY
723 PM EST WED JAN 30 2013
.SYNOPSIS...
RAIN...HEAVY AT TIMES WILL FALL ACROSS THE REGION TONIGHT AHEAD OF A
COLD FRONT THAT WILL SWEEP ACROSS THE REGION WHICH WILL SEND
TEMPERATURES BACK TO SEASONAL NORMALS. AS THE COLD AIR DEEPENS ON
THURSDAY...LAKE EFFECT SNOWS WILL SET UP IN THE TRADITIONAL
SNOWBELTS EAST AND SOUTHEAST OF THE LAKES...THEN WILL CONTINUE
THROUGH THE END OF THE WEEK.
&&
.NEAR TERM /THROUGH THURSDAY/...
LOW PRESSURE ACROSS LAKE HURON WILL LIFT NORTHEAST ACROSS SOUTHERN
ONTARIO TONIGHT. THIS WILL BRING A COLD FRONT ACROSS THE REGION
TONIGHT...FORECAST TO ENTER FAR WESTERN NEW YORK AROUND
MIDNIGHT...THEN SWEEP RAPIDLY TO THE EAST THROUGH THE EARLY
MORNING HOURS. THIS WILL CAUSE AN ABRUPT DROP IN TEMPERATURES. IN
ADDITION....THIS SYSTEM WILL SET UP A DEEP SOUTHERLY FLOW OUT
AHEAD OF IT...WHICH WILL TRANSPORT MOISTURE FROM PENNSYLVANIA AND
INTO CENTRAL NEW YORK TONIGHT.
A BLEND OF RADAR AND HRRR MODEL GUIDANCE THROUGH 700 PM SHOW A
SLIGHTLY LATER START TIME IN RAIN...WITH A SHARP CUT OFF ON THE
WEST SIDE OF THE HEAVIER RAINS. AT THIS TIME...IT APPEARS MORE
LIKELY THAT THE HEAVIEST RAINS WILL BE EAST OF THE GENESEE RIVER.
THERE WILL BE NO CHANGE TO HEADLINES AT THIS TIME...BUT THERE
APPEARS TO BE A DIMINISHING THREAT FOR FLOODING IN WESTERN
PORTIONS OF THE FLOOD WATCH...WHILE TRENDS SUPPORT A CONTINUED
RISK...ESPECIALLY EAST OF LAKE ONTARIO IN THE BLACK RIVER BASIN
AND ITS TRIBUTARIES.
1. RAINFALL...AS THE UPPER LEVEL SHORTWAVE CONTINUES TO DEEPEN AN
UPPER LEVEL TROUGH OVER THE CENTRAL GREAT LAKES THE COLD FRONT
PASSAGE IS NOW SLIGHTLY SLOWER...ALLOWING FOR THE AXIS OF HEAVIEST
RAINFALL TO NOW FALL ACROSS EASTERN PORTIONS OF THE CWA. WITH A VERY
MOIST AIRMASS FOR THIS TIME OF YEAR AND THE DEEP MOISTURE ALREADY
SEEN STREAMING NORTHWARD TOWARDS THE GREAT LAKES AND NEW ENGLAND
REGION HEAVY RAINFALL IS LIKELY OVERNIGHT. LIFT FROM THE COLD
FRONT...DIFFLUENCE IN THE UPPER LEVELS AND A NEARBY RIGHT ENTRANCE
REGION OF A 150 KNOT 250 HPA JET WILL LEAD TO DEEP SYNOPTIC LIFT.
THE 12Z SUITE OF THE ECMWF...GFS...NAM...AS WELL AS THE 09Z SREF
MEAN DISPLAYING CLOSE TO AN INCH AND A HALF TO AS MUCH AS 2 INCHES
OF RAINFALL BY 12Z TOMORROW FROM PORTIONS OF THE UPPER GENESEE
VALLEY AND ACROSS THE FINGER LAKES REGION AND TOWARDS EASTERN LAKE
ONTARIO REGION. LESS RAINFALL...LIKELY AROUND AN INCH OR LESS WILL
FALL ACROSS THE NIAGARA FRONTIER AND FAR WESTERN SOUTHERN TIER. THE
FLOODING POTENTIAL WILL BE OF SMALL CREEKS AND STREAMS AS WELL AS
PONDING WATER FROM HEAVY RAINFALL OVER A SATURATED/FROZEN GROUND. THE
SREF EXPERIMENTAL MODEL ENSEMBLE RIVER FORECASTS ARE MORE BULLISH
WITH RIVER FLOOD POTENTIAL THAN THE GEFS AND THE NAEFS. ANY LARGER
RIVER OR CREEKS THAT MAY REACH ACTION OR FLOOD STAGE MAY BE ACROSS
THE UPPER GENESEE AND EASTERN LAKE ONTARIO REGION...AS SUGGESTED BY
THE GEFS AND THE NAEFS...AS WELL AS WHERE THE AXIS OF HEAVY RAIN IS
LIKELY. SINCE THE FLOODING CONCERNS WILL CONTINUE EVEN AFTER THE
RAIN STOPS AND TEMPERATURES FALL BELOW FREEZING...HAVE ELECTED TO
EXTEND THE FLOOD WATCH UNTIL 18Z THURSDAY FOR ALLEGANY COUNTY
THROUGH THE FINGER LAKES AND EASTERN LAKE ONTARIO REGION.
2. STRONG WINDS...THE AFOREMENTIONED STORM SYSTEM WILL DEEPEN FROM
AROUND 985MB 00Z TONIGHT TO 970MB 12Z TOMORROW MORNING JUST NORTH OF
VERMONT...AND THEN BELOW 960 MB BY 00Z FRIDAY ACROSS EASTERN QUEBEC.
THIS RAPID DEEPENING...COMBINED WITH 6 TO 8 MB ISALLOBARIC PRESSURE
RISES WITHIN COLD AIR ADVECTION FOLLOWING THE COLD FRONT SHOULD BE
ABLE TO MIX A 50 KNOT JET AT 925 HPA DOWN TO THE SURFACE. GIVEN THE
STRONG AND VERY DYNAMIC NATURE OF THIS SYSTEM...ITS ASSOCIATED WIND
FIELDS WILL ALSO BE QUITE STRONG. WE WILL UPGRADE THE ADVISORY TO A
WARNING FOR A GOOD PORTION OF THE CWA. WIND GUSTS UP TO 60 MPH ARE
LIKELY IN FAVORED AREAS ALONG THE LAKE ERIE SHORELINE INLAND ACROSS
SOUTHERN LAKE ONTARIO AND THROUGH THE EASTERN LAKE ONTARIO REGION.
FOR OUR INLAND COUNTIES OF WYOMING...ALLEGANY...LIVINGSTON AND
ONTARIO WE WILL LEAVE A HIGH END WIND ADVISORY AS THE DEEPENING LOW
MAY BE TOO FAR NORTH TO ALLOW FOR WARNING CRITERIA WINDS HERE.
3. LAKE EFFECT SNOW...FOLLOWING THE PASSAGE OF THE COLD FRONT -14C
TO -16C 850 HPA AIR TEMPERATURES WILL BE CROSSING THE LAKES. AT
FIRST WINDS MAY BE TO STRONG FOR GOOD FORMATION OF LAKE EFFECT SNOW
BANDS WITH THE WINDS SHEARING AWAY THE LAKE BAND FORMATION. ALSO
WITH THE STRONG WINDS RESIDENT TIME OVER THE LAKE BODIES WILL BE
LIMITED. AS WINDS DIMINISH THROUGH THE AFTERNOON AND COLD AIR
DEEPENS...AND LAKE INDUCED EQUILIBRIUM LEVELS RISE TOWARDS 7 TO 9K
FEET A BAND OF SNOW SHOULD BE FORMING OFF BOTH LAKE ERIE AND LAKE
ONTARIO. THE NAM...AND TO A DEGREE THE GFS HAS DEEP SYNOPTIC
MOISTURE REMAINING IN THE SNOW GROWTH ZONE...WHICH WILL BE FALLING
WITH THE COLD AIR ADVECTION.
OFF LAKE ONTARIO...WIND FIELD CONVERGENCE OVER LAKE ONTARIO IS
LEADING TO IMPRESSIVE OMEGA FIELDS BY THURSDAY AFTERNOON WHERE A
BAND OF LAKE EFFECT SNOW MAY BEGIN TO PRODUCE SNOWFALL RATES UP TO 2
INCHES PER HOUR. FOLLOWING THE SURFACE LOW AND UPPER LEVEL TROUGH
WINDS WILL BEGIN TO VEER THROUGH THE DAY DROPPING THE LAKE EFFECT
SNOW BAND SOUTH OF JEFFERSON COUNTY. FOR THIS REASON WILL LEAVE
JEFFERSON COUNTY AS A HIGH END LAKE EFFECT SNOW ADVISORY...AND HAVE
WARNINGS FOR LEWIS AND OSWEGO COUNTIES WHERE THE BAND WILL LIKELY
FALL LONGER.
OFF LAKE ERIE...A WESTERLY FLOW OVER THE STILL OPEN WATERS OF LAKE
ERIE WILL BRING MULTI BANDED STRUCTURE SNOW BANDS ACROSS THE SOUTHERN
TIER. CONFIDENCE IS GREATER ACROSS CHAUTAUQUA AND CATTARAUGUS COUNTIES
THAN SOUTHERN ERIE AND WYOMING COUNTIES FOR WARNING CRITERIA SNOW.
WILL UPGRADE THE WATCH TO A LAKE EFFECT WARNING ACROSS THE SOUTHERN
TIER...WHILE LEAVING ADVISORIES FOR SOUTHERN TIER AND WYOMING
COUNTIES.
4. REGARDING TEMPERATURES...RECORDED HIGHS WERE SHATTERED ACROSS
MUCH OF THE REGION TODAY WITH MORNING AND EARLY AFTERNOON HIGHS
REACHING NEAR 10 DEGREES ABOVE RECORD VALUES FOR THE DATE.
THE NEW RECORDS FOR TODAY...
BUFFALO.....66 (PREVIOUS WAS 56 IN 1916)
ROCHESTER...64 (PREVIOUS WAS 55 IN 1974)
WATERTOWN...63 (PREVIOUS WAS 52 IN 1995)
THESE READINGS ARE STILL SEVERAL DEGREES SHY OF THE ALLTIME
MONTHLY RECORD HIGH TEMPERATURE WHICH ARE AS FOLLOWS:
BUFFALO...72 IN 1950.
ROCHESTER...74 IN 1950...CORRECTED
WATERTOWN...66 IN 1995.
THE COLD FRONT WILL SWEEP ACROSS THE REGION TONIGHT SENDING
TEMPERATURES BACK TO SEASONAL NORMS...WITH MANY AREAS DOWN INTO THE
UPPER 20S AND LOW 30S BY TOMORROW MORNING. WITH THE RAIN OVERNIGHT
THE PROSPECTS FOR BLACK ICE WILL BE PRESENT AS WE QUICKLY COOL
FURTHER INTO THE MID AND UPPER 20S BY MID MORNING.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
HEAVY LAKE EFFECT SNOWS SHOULD BE ONGOING ON A WESTERLY FLOW
REGIME AT THE START OF THE PERIOD. BUFR PROFILES FROM THURSDAY
NIGHT THROUGH AT LEAST THE DAYTIME HOURS OF FRIDAY CONTINUE TO
LOOK RATHER IMPRESSIVE...AS A DEEP LAYERED CYCLONIC FLOW REGIME IS
WELL ESTABLISHED. MOISTURE PROFILES LOOK QUITE ADEQUATE WITH
SATURATION WELL UP THROUGH 10K FEET AND DEEPER AT TIMES AS A
COUPLE OF REINFORCING WEAK SHORTWAVES WORK THROUGH THE MEAN WEST
NORTHWEST FLOW. THE BIGGEST FACTOR THAT COULD LIMIT TOTALS WILL BE
THE VEERING WINDS IN RESPONSE TO A SHORTWAVE CROSSING THE LOWER
LAKES. THIS WILL TEND TO PUSH THE LAKE BANDS...ESPECIALLY ACROSS
LAKE ONTARIO SOUTHWARD. THIS COULD BRING THE PRIME LAKE EFFECT
FOCUS ALONG THE SOUTH SHORE OF LAKE ONTARIO...WHICH COULD BRING AT
LEAST ADVISORY OR GREATER TOTALS TO THIS AREA INCLUDING THE
ROCHESTER METRO AREA. FEEL A BIT MORE CONFIDENT WITH THE AREA FROM
WAYNE OVER TO NORTHERN CAYUGA AT THIS POINT...THEREFORE WILL ISSUE
A LAKE EFFECT SNOW WATCH FOR THAT AREA...BUT IT IS HIGHLY POSSIBLE
THAT LAKE EFFECT HEADLINES MAY NEED TO BE ISSUED FARTHER TO THE
WEST.
ANOTHER SHORTWAVE APPROACHING THE REGION FRIDAY NIGHT AND SATURDAY
MAY REORIENT THE LAKES SNOWS FOR A TIME NORTHWARD AS THE FLOW
BACKS TO WEST SOUTHWEST...POTENTIALLY BRINGING SOME ACCUMULATING
SNOWS INTO PORTIONS OF THE BUFFALO METRO AND WATERTOWN AREAS. THE
PASSAGE OF THE SHORTWAVE SHOULD RE-ESTABLISH THE LAKE SNOWS BACK
SOUTHWARD LATER SATURDAY AND SATURDAY NIGHT.
MUCH COLDER AIR MASS ACROSS THE AREA FRIDAY AND SATURDAY WITH
DAYTIME HIGHS IN THE TEENS AND 20S...WITH WIND CHILLS PERIODICALLY
BELOW ZERO.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
THE VERY COLD AIR REMAINS IN PLACE SUNDAY...BEFORE A GRADUAL
MODIFICATION OF THE AIR MASS OCCURS INTO EARLY NEXT WEEK AS THE
UPPER TROUGH SHIFTS TO THE EAST. TWO CLIPPER TYPE WAVES LOOK TO
IMPACT THE LOWER LAKES REGION DURING THIS TIME FRAME. ONE WAVE MOVES
THROUGH ON SUNDAY WHICH MAY SERVE TO ENHANCE THE ONGOING LAKE EFFECT
SNOWS IN A WESTERLY FLOW REGIME. THE SECOND WAVE LOOKS TO MOVE
THROUGH LATE MONDAY OR EARLY TUESDAY AND APPEARS TO BE RATHER ROBUST
AND GIVEN THE PROJECTED TRACK OF THE ASSOCIATED SURFACE LOW COULD
BRING THE POTENTIAL FOR A GENERAL WIDESPREAD SEVERAL INCHES OF SNOW.
BEHIND THIS WAKE A COLDER FLOW DEVELOPS WHICH MAY REDEVELOP SOME
LAKE SNOWS BUT LACK OF SIGNIFICANT MOISTURE COULD LIMIT SNOWFALL
POTENTIAL.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
LLWS WILL QUICKLY SUBSIDE AS A STRONG LLJ EXITS TO THE EAST.
MEANWHILE...A BROAD AREA OF SHOWERS WILL MOVE INTO THE
REGION...BOTH STREAMING FROM THE SOUTH AND AHEAD OF A COLD FRONT.
THIS WILL BRING A PERIOD OF RAIN TO ALL TAF SITES...BUT WITH THE
SOUTHERLY DOWNSLOPE COMPONENT TO THE FLOW CIGS WILL BE INITIALLY
SLOW TO DROP.
AS THE COLD FRONT CROSS THE AREA BETWEEN 04Z AND 09Z...CIGS WILL
DROP AND IFR CONDITIONS WILL BECOME MORE WIDESPREAD...ESPECIALLY
DOWNWIND OF THE LAKES. RAIN WILL MIX WITH...THEN CHANGE TO SNOW
BEFORE DAYBREAK THURSDAY.
STRONG COLD AIR ADVECTION BEHIND THE DEPARTING FRONT WILL INCREASE
MIXING AND RAPIDLY STRENGTHEN WESTERLY WINDS OVERNIGHT. LATE TONIGHT
INTO THURSDAY MORNING...EXPECT WINDS TO GUST TO 40-50 KNOTS IN MOST
LOCATIONS...BEFORE TAPERING OFF LATE THURSDAY AFTERNOON. LAKE
SNOWS WILL DEVELOP EAST OF THE LAKES. THESE WILL LIKELY STAY OUT
OF BUF/IAG/ROC...BUT SHOULD IMPACT ART/JHW FOR A PERIOD.
CONDITIONS WILL VARY SIGNIFICANTLY IN AND OUT OF LAKE EFFECT BANDS.
OUTLOOK...
THURSDAY NIGHT THROUGH SATURDAY...MVFR WITH LOCALIZED IFR IN LAKE
EFFECT SNOW EAST OF THE LAKES.
SUNDAY...MAINLY VFR WITH MVFR IN LOCALIZED LAKE EFFECT SNOW SHOWERS.
MONDAY...VFR.
&&
.MARINE...
A COMPLEX AREA OF LOW PRESSURE FROM SOUTHERN CANADA AND THROUGH THE
CENTRAL GREAT LAKES REGION THIS AFTERNOON WILL LIFT NORTHEASTWARD
AND DEEPEN TONIGHT AND TOMORROW. A COLD FRONT SWINGING ACROSS THE
LAKES...COUPLED WITH STRONG COLD AIR ADVECTION AND RAPID DEEPENING
OF THE SURFACE LOW WILL INCREASE WINDS QUICKLY TO GALE FORCE
FOLLOWING THE PASSAGE OF THE FRONT TONIGHT...WITH GALES THEN
CONTINUING THROUGH MUCH OF THURSDAY. FOR THIS REASON...GALE WARNINGS
WILL CONTINUE AS OUTLINED ON THE LAKES. WINDS AND WAVES WILL STILL
REMAIN STRONG THURSDAY EVENING THROUGH SATURDAY...BEFORE DIMINISHING
TO BELOW SMALL CRAFT CONDITIONS BY SATURDAY NIGHT.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...HIGH WIND WARNING UNTIL 4 PM EST THURSDAY FOR NYZ001>005-010-
011-019-020-085.
LAKE EFFECT SNOW ADVISORY FROM 10 AM THURSDAY TO 6 PM EST
FRIDAY FOR NYZ012-085.
HIGH WIND WARNING FROM 10 PM THIS EVENING TO 4 PM EST THURSDAY
FOR NYZ006>008.
LAKE EFFECT SNOW ADVISORY FROM 10 AM THURSDAY TO 1 AM EST
FRIDAY FOR NYZ007.
FLOOD WATCH THROUGH THURSDAY AFTERNOON FOR NYZ004>008-013-014-
021.
LAKE EFFECT SNOW WARNING FROM 10 AM THURSDAY TO 6 PM EST
FRIDAY FOR NYZ006-008-019-020.
LAKE EFFECT SNOW WATCH FROM THURSDAY EVENING THROUGH FRIDAY
AFTERNOON FOR NYZ004-005.
WIND ADVISORY UNTIL 4 PM EST THURSDAY FOR NYZ012>014-021.
FLOOD WATCH THROUGH THURSDAY MORNING FOR NYZ019-020.
MARINE...GALE WARNING FROM 10 PM THIS EVENING TO 4 PM EST THURSDAY FOR
LEZ040-041.
GALE WARNING FROM 10 PM THIS EVENING TO 10 AM EST THURSDAY
FOR LEZ020.
SMALL CRAFT ADVISORY UNTIL 4 PM EST THURSDAY FOR
LOZ030.
GALE WARNING FROM 1 AM TO 4 PM EST THURSDAY FOR LOZ042>045-
062>065.
&&
$$
SYNOPSIS...THOMAS
NEAR TERM...APFFEL/THOMAS
SHORT TERM...TMA
LONG TERM...TMA
AVIATION...APFFEL
MARINE...THOMAS
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
615 PM EST WED JAN 30 2013
.SYNOPSIS...
WINDY AND MILD CONDITIONS WILL CONTINUE AHEAD OF A STRONG COLD
FRONT. FAST MOVING SHOWERS AND ISOLATED THUNDERSTORMS TONIGHT
COULD PRODUCE LOCALIZED DAMAGING WIND GUSTS. DRY AND COOL
CONDITIONS WILL FOLLOW THE FRONT THURSDAY THROUGH EARLY NEXT WEEK
AS HIGH PRESSURE MOVES INTO THE REGION.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 300 PM WEDNESDAY...THE STRONG COLD FRONT EXTENDS FROM EASTERN
TENNESSEE TO THE FLORIDA PANHANDLE AND IS CATCHING UP QUITE RAPIDLY
WITH THE PREFRONTAL SQUALL LINE. ALTHOUGH THERE ARE STILL SOME
TIMING DIFFERENCES AMONG THE VARIOUS 12Z MODELS...THE CONSENSUS IS
FOR THE FRONT TO ARRIVE IN THE SC PEE DEE REGION JUST BEFORE
MIDNIGHT...MOVING THROUGH THE GRAND STRAND AND ELIZABETHTOWN/
WHITEVILLE AREAS AROUND MIDNIGHT...THEN THROUGH WILMINGTON AND THE
CAPE FEAR COAST AROUND 1 AM. THIS WILL BE A VERY QUICK EVENT FOR ANY
ONE LOCATION AND THE SQUALL LINE SHOULD TRAVERSE OUR ENTIRE FORECAST
AREA IN 3 HOURS OR LESS.
STRONG SOUTH WINDS OUT AHEAD OF THE FRONT/SQUALL LINE HAVE GUSTED TO
39 MPH IN FLORENCE AND 36 MPH IN WILMINGTON. GUSTS OVER 40 MPH
SHOULD DEVELOP BEFORE SUNSET AS STRONGER WINDS IN THE 1000-2000 FT
LAYER GET ENTRAINED IN TURBULENT MIXING THROUGHOUT THE DAYTIME
BOUNDARY LAYER. AS THE SURFACE COOLS DOWN TO 68-70 DEGREES THIS
EVENING AND THE BOUNDARY LAYER FLATTENS TO ONLY A FEW HUNDRED FEET
THICK...WINDS AS LOW AS 1000 FT AGL WILL INCREASE TO 40-50 KNOTS.
SOME OF THIS MOMENTUM MAY STILL TUMBLE DOWN TO THE SURFACE WITH
GUSTS UP 45 MPH EXPECTED.
A SQUALL LINE CONSISTING OF LINEAR FORCED CONVECTION WITHIN A REGION
OF HIGHLY CONVERGENT LOW-LEVEL FLOW JUST AHEAD OF THE FRONT WILL BE
CAPABLE OF PRODUCING DAMAGING WIND GUSTS VIA HEAVY RAINFALL
TRANSPORTING STRONG WINDS DOWN FROM ALOFT. CONVECTIVE CELLS...
ASSUMING A 15000 FT CELL DEPTH AND MOVEMENT AT 70% OF THE MEAN
FLOW...COULD MOVE AS QUICKLY AS 65 KNOTS. THE POTENTIAL FOR
WIDESPREAD DAMAGING WINDS DOES EXIST. ASSUMING SURFACE TEMPS OF
68-70 DEGREES AND SURFACE DEWPOINTS IN THE LOWER 60S...SURFACE-BASED
CAPE SHOULD REMAIN NEAR ZERO TONIGHT. HOWEVER THE SURFACE-BASED
INVERSION WILL ALSO BE WEAK AND MAY NOT PROVIDE AN EFFECTIVE BARRIER
TO STRONG WINDS PUNCHING DOWN FROM ALOFT.
THE BEST POTENTIAL FOR SEVERE WEATHER SHOULD BE NEAR AND WEST OF
I-95...BUT EVEN AT THE COAST THE THREAT IS STILL LARGE ENOUGH FOR
CONCERN. SEVERE THUNDERSTORM WATCHES WILL PROBABLY BE NEEDED FOR THE
AREA TONIGHT. THANKFULLY...THE SHALLOW DEPTH OF THE CONVECTION PLUS
WEAK UPDRAFT STRENGTH SHOULD PRECLUDE ANY HAIL THREAT.
AFTER THE FRONT SLIDES OFFSHORE...MUCH DRIER COOLER AIR WILL BUILD
IN WITH CLEARING SKIES. LOWS SHOULD RANGE FROM 45-50.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 300 PM WEDNESDAY...STRONG WESTERLY WINDS WILL ADVECT MUCH
COLDER AND DRIER AIR INTO REGION BEHIND EXITING COLD FRONT LOCATED
WELL OFF THE COAST BY THURS MORNING. A VERY BROAD MID TO UPPER
TROUGH WILL SHIFT EAST THROUGH THE PERIOD FINALLY LIFTING OFF TO
THE NORTHEAST BY FRI NIGHT. AS THIS TROUGH MOVES EAST IT WILL
DRIVE A SECONDARY BOUNDARY THROUGH THE AREA BY FRI MORNING. THIS
WILL PROVIDE A REINFORCING SHOT OF COLD AND DRY AIR INTO THE AREA
AS DEEP NW FLOW SETS UP ON FRIDAY.
OVERALL A POTENT STORM SYSTEM WILL LIFT OFF TO THE NORTHEAST AS
HIGH PRESSURE RIDGES UP FROM THE GULF COAST ON THURSDAY....BUT
STRONG HIGH PRESSURE WILL BUILD DOWN FROM CANADA REACHING INTO THE
CENTRAL CONUS BY THURS NIGHT AND SHIFTING EAST OVER THE LOCAL AREA
BY LATE FRI INTO EARLY SAT. THIS WILL MAINTAIN A TIGHTENED
GRADIENT FLOW THROUGH THURS AND THEN WINDS MAY BACK SLIGHTLY
BEFORE NEXT DRY FRONTAL BOUNDARY MOVES THROUGH EARLY FRI WITH A
SPIKE UP OF WINDS BEFORE FINALLY DIMINISHING AND VEERING MORE
NORTH BY FRI NIGHT. THESE STRONG WEST TO NORTHWEST WINDS WILL
MAINTAIN CAA THROUGH MUCH OF THE PERIOD. THERE WILL ONLY BE A
BRIEF PERIOD OF MORE NEUTRAL ADVECTION AHEAD OF DRY COLD FRONT FRI
MORNING. THEREFORE 850 TEMPS DROP FROM 13C JUST AHEAD OF INITIAL
COLD FRONT EARLY THURS MORNING DOWN LESS THAN 0C BY THURS AFTN AND
THEN WILL DROP AN ADDITIONAL SEVERAL DEGREES DOWN TO -8C BY FRI
EVENING. TEMPS REACHING THE MID 50S...ALREADY 20 DEGREES COOLER
THAN ON THURS...WILL HAVE TROUBLE REACHING INTO THE 50S ON FRI AS
COLD ARCTIC HIGH PRESSURE BUILDS DOWN INTO THE AREA. OVERNIGHT
LOWS WILL DROP DOWN TOWARD FREEZING THURS NIGHT IN CAA BUT FRI
NIGHT TEMPS WILL PLUMMET ONCE WINDS DROP OFF IN THE EVENING. A
MUCH MORE IDEAL RADIATIONAL COOLING NIGHT WILL OCCUR ON FRIDAY
NIGHT AS HIGH SHIFTS OVERHEAD...MAKING FOR ONE OF THE COLDEST
NIGHTS OF THE SEASON THUS FAR...WITH WIDESPREAD READINGS IN THE
20S.
DRY AIR WILL RUN SIMILAR TO TEMPS WITH A MAJOR DROP OFF BEHIND
FIRST FRONT AND THEN A PLATEAU AND MINOR INCREASE JUST AHEAD OF
DRY POLAR COLD FRONT FRI MORNING AND THEN ANOTHER NOSE DIVE
THROUGH FRI AFTN. THE PCP WATER DROP OFF FROM 1.6 INCHES VERY
EARLY THURS MORNING DOWN TO A QUARTER OF AN INCH BY LATE THURS
MORNING AND THEN DOWN CLOSE TO A TENTH OF AN INCH BY FRI AFTN.
WITH SUCH A DRY AIR MASS IN PLACE...EXPECT SUNSHINE THROUGH MOST
OF THE PERIOD. MAY SEE SOME CLOUDS WITH LINGERING MOISTURE THROUGH
THURS MORNING AFTER RAINFALL FROM FRONT...AND A SLIGHT SPIKE AHEAD
OF FRONT FRI MORNING.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 300 PM WEDNESDAY...A RATHER REPETITIVE PATTERN FOR THE
EXTENDED AS AREAS OF HIGH PRESSURE PUSH OFFSHORE AHEAD OF A SERIES
OF WEAK COLD FRONTS.
FIRST OF THESE OCCURS SATURDAY AS DIFFUSE HIGH PRESSURE MOVES ACROSS
THE AREA AND OFFSHORE...LEAVING A BRIEF PERIOD OF MOIST RETURN FLOW
INTO THE CAROLINAS. THIS IS JUST IN ADVANCE OF A COLD FRONT WHICH
WILL CROSS THE AREA VERY EARLY SUNDAY MORNING. LIMITED FORCING
COMBINED WITH ONLY MARGINAL PWATS SUGGESTS FROPA WILL BE DRY...AND
ONLY ACT TO REINFORCE THE COOL AIR. HOWEVER...ANY WEAK CAA REMAINS
WELL DISPLACED BEHIND THE FRONT...SO SUNDAY WILL END UP BEING WARMER
THAN SATURDAY...ALTHOUGH BOTH DAYS WILL BE AROUND TO SLIGHTLY BELOW
CLIMO.
ANOTHER LARGE BUT WEAK AREA OF HIGH PRESSURE BUILDS DOWN FROM THE NW
LATE SUNDAY AND PERSISTS INTO TUESDAY WHILE SLOWLY DRIFTING ACROSS
THE REGION. THIS CONTINUES THE COOL AND DRY WEATHER WITH NEAR TO
SLIGHTLY-BELOW SEASONABLE TEMPS. THIS HIGH PRESSURE THEN DRIFTS
OFFSHORE TUESDAY AHEAD OF ANOTHER COLD FRONT PROGGED TO CROSS THE
AREA LATE IN THE DAY. GUIDANCE SHOWING CONSIDERABLE AMPLITUDE
DIFFERENCES IN THE TROUGH DRIVING THIS FRONT WHICH WILL HAVE
SIGNIFICANT IMPACT ON PRECIP POTENTIAL. FOR NOW WILL KEEP INHERITED
SCHC/SILENT POP FOR D6 SINCE BENEFICIAL CHANGES CANNOT BE MADE AT
THIS TIME. TUESDAY WILL LIKELY BE THE WARMEST DAY OF THE PERIOD
THOUGH AHEAD OF THE COLD FRONT...WITH TEMPS RETURNING TO BELOW CLIMO
FOR WEDNESDAY AS ANOTHER AREA OF HIGH PRESSURE RIDGES DOWN FROM THE
NW.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
AS OF 00Z...STRONG COLD FRONT TO IMPACT THE TERMINALS TONIGHT WITH
GUSTY WINDS AND A POTENTIAL SQUALL LINE WITH SHOWERS/ISOLATED
THUNDERSTORMS.
COLD FRONT CURRENTLY ACROSS WESTERN PORTIONS OF SC/NC WILL PUSH EAST
TONIGHT AND BE ACCOMPANIED BY A LINE OF SHOWERS WITH ISOLATED
THUNDERSTORMS. HRRR APPEARS TO BE INITIALIZING BETTER THAN ANY OF
THE OTHER HIGH-RES GUIDANCE...SO HAVE RELIED HEAVILY ON THIS MODEL
FOR TIMING CONVECTION AT THE TERMINALS...AND EXPECT THE SQUALL LINE
TO IMPACT FLO/LBT AROUND 03Z...RACING EAST TO ILM AROUND 06Z.
ATTM...NO IFR HAS BEEN INTRODUCED INTO THE CURRENT SET OF TAFS DUE
TO UNCERTAINTY IN EXACT TIMING AND LIKELY SHORT-DURATION OF ANY
PRECIP INDUCED IFR. PREFER TO HANDLE ANY IFR WITH AMD/TEMPO GROUPS
AS THE CONVECTION UNFOLDS. HAVE SHOWN A 2-HR TEMPO GROUP AT ALL
TERMINALS FOR THE HEAVIEST CONVECTION WITH MVFR AND INCREASED WIND
GUSTS...BUT STRONGER GUSTS ARE POSSIBLE THAN WHAT IS CURRENTLY
DEPICTED.
OTHER CONCERN IS THE STRONG PRE-FRONTAL AND POST-FRONTAL WINDS. S/SW
WINDS WILL CONTINUE TO INCREASE TONIGHT AS A STRENGTHENING LOW LEVEL
JET MOVES OVERHEAD. FOR THIS REASON HAVE SHOWN INCREASING LLWS IN
ALL TAFS WITH 30 KT GUSTS LIKELY THROUGH THE NIGHT...EVEN OUTSIDE OF
CONVECTION. A SUDDEN WIND SHIFT WILL OCCUR WITH THE FROPA
TONIGHT...AND AWW`S MAY BE REQUIRED FOR ILM/MYR LATER TONIGHT AS THE
FRONT CROSSES...AND WINDS SHIFT SUDDENLY TO THE WEST.
RAPID DRYING OCCURS BEHIND THE FRONT AND SKC WILL BECOME THE SKY
CONDITION ON THURSDAY. ALTHOUGH IT WILL BE CLEAR...STRONG WESTERLY
WINDS WILL PERSIST THROUGH THE DAY...GUSTING TO 25 KTS THROUGH THE
END OF THE VALID PERIOD.
EXTENDED OUTLOOK...VFR THROUGH THE EXTENDED.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 300 PM WEDNESDAY...SOUTH WINDS WILL INCREASE THROUGH THE
EVENING AHEAD OF A STRONG COLD FRONT NOW LOCATED FROM EASTERN
TENNESSEE SOUTH TO THE FLORIDA PANHANDLE. ALTHOUGH WINDS ARE
CURRENTLY ONLY 20-30 KNOTS ACROSS THE COASTAL WATERS...A 3-4 HOUR
PERIOD OF MUCH STRONGER WINDS IS EXPECTED TO DEVELOP JUST AHEAD OF
THE FRONT THIS EVENING. 35-40 KNOT WINDS MAY GUST MUCH HIGHER AS A
NARROW LINE OF SHOWERS AND EMBEDDED THUNDERSTORMS PUSH OFFSHORE JUST
AFTER MIDNIGHT. A SEVERE THUNDERSTORM WATCH PROBABLY WILL BE NEEDED
TO ADDRESS THIS POTENTIAL. BEHIND THE FRONT...WINDS WILL TURN
WESTERLY IN THE 25-35 KNOT RANGE THROUGH DAYBREAK. SEAS CURRENTLY
4-7 FT WILL BUILD THIS EVENING TO 8-12 FEET AWAY FROM SHORE WITH THE
STRONG SOUTH WINDS.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 300 PM WEDNESDAY...ALTHOUGH SEAS WILL BE ON THE DECREASE
THROUGH MUCH OF THE PERIOD IN STRONG OFF SHORE FLOW...TIGHTENED
GRADIENT FLOW AND COLD SURGE BEHIND FRONT THURS AND AGAIN ON FRI WILL
MAINTAIN SEAS ABOVE SCA THROUGH A GOOD PORTION OF THE SHORT TERM
PERIOD IN THE OUTER WATERS. WESTERLY WINDS UP AROUND 25 KTS WILL
DROP THROUGH THURS ALLOWING OFF SHORE SEAS TO SUBSIDE FROM 8 TO
10 FT FRI MORNING DOWN TO 5 FT BY THURS NIGHT.
WINDS WILL BACK SLIGHTLY TO THE SW THURS NIGHT INTO EARLY FRI
AHEAD OF APPROACHING DRY COLD FRONT BEFORE SPIKING UP IN SURGE
BEHIND FRONT. THIS WILL PRODUCE SEAS AROUND 6 FT ONCE AGAIN FOR A
FEW HOURS ON FRI. THE NEAR SHORE WATERS WILL DECREASE THROUGH
THURS IN OFF SHORE FLOW DOWN TO 2 TO 4 FT AND MAY SPIKE UP A BIT
FRI MORNING BUT OVERALL WILL DROP OFF SOME MORE LATE FRI AS HIGH
PRESSURE SHIFTS OVERHEAD ALLOWING FOR LOCAL SEAS TO DROP TO 2 TO 3 FT
IN ALL WATERS.
LONG TERM /SATURDAY THROUGH MONDAY/...
AS OF 300 PM WEDNESDAY...OTHER THAN A WEAK COLD FRONT
SUNDAY...DIFFUSE HIGH PRESSURE WILL DOMINATE THE WEATHER ACROSS THE
WATERS THROUGH THE EXTENDED. ONE AREA OF HIGH PRESSURE WILL MOVE
ACROSS THE WATERS SATURDAY CREATING LIGHT AND VARIABLE
WINDS...VEERING TO THE SW AND INCREASING TO AROUND 10 KTS LATE IN
THE DAY. THIS AHEAD OF A COLD FRONT WHICH WILL CROSS DURING
SUNDAY...TURNING WINDS TO THE W/NW AT 10-15 KTS ON SUNDAY BEFORE
SLOWLY EASING TO LIGHT AND VARIABLE AGAIN MONDAY AS HIGH PRESSURE
BUILDS BACK OVER THE WATERS. SEAS WILL BE PRIMARILY WIND-DRIVEN
THROUGH THE PERIOD...1-2 FT SATURDAY AND MONDAY...INCREASING FOR A
SHORT TIME SUNDAY UP TO 2-4 FT WITH A NW WIND WAVE DOMINANT.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...WIND ADVISORY UNTIL 6 AM EST THURSDAY FOR SCZ017-023-024-032-
033-039-053>056.
NC...WIND ADVISORY UNTIL 6 AM EST THURSDAY FOR NCZ087-096-099-
105>110.
MARINE...GALE WARNING FROM 4 PM THIS AFTERNOON TO 6 AM EST THURSDAY
FOR AMZ250-252-254-256.
&&
$$
NEAR TERM...TRA
SHORT TERM...RGZ
LONG TERM...JDW
AVIATION...JDW
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
1043 PM MST MON JAN 28 2013
.UPDATE...SLOW MOVING BAROCLINIC ZONE AND ASSOCIATED DISTURBED MID
LEVEL JET AXIS CONTINUES TO SHIFT EAST...WITH SNOW SLOWLY TRENDING
EAST OUT OF THE FA. ANOTHER SUBTLE IMPULSE IS EJECTING NE ACROSS
NEB AND WILL SUPPORT CONTINUED SNOW ACROSS FAR SCNTRAL
SD...ALTHOUGH SNOW WILL WANE IN INTENSITY AS THE BEST LIFT AND
BETTER MOISTURE CONTINUES TO SHIFT EAST. HENCE...DROPPED THE WEST
END OF THE ADV...RETAINING THE EASTERN PORTION WHERE ANOTHER 1 TO
2 INCHES OF SNOW IS POSSIBLE INTO EARLY MORNING.
OTHERWISE...ADJUSTED SKY GRIDS GIVEN SOME EXPECTED CLEARING PER
WAKE SUBSIDENCE.
&&
.AVIATION...06Z TAFS
UPPER LEVEL IMPULSE AND ASSOCIATED SNOW WILL CONTINUE TO SHIFT EAST
ACROSS THE REGION. MVFR/IFR CONDITIONS OVER MUCH OF SOUTH CENTRAL
AND CENTRAL SOUTH DAKOTA WILL TREND UP TO HIGH END MVFR AND VFR
THROUGH THE PERIOD AS THIS DISTURBANCE EXITS THE REGION AND SNOW
ENDS EARLY TUES MORNING. VFR CONDITIONS EXPECT MOST PLACES INTO
TUES AFTERNOON. A FAST MOVING CLIPPER SYSTEM WILL PUSH INTO THE
NORTHERN PLAINS TUESDAY AFTERNOON...AFFECTING THE FA NW-SE THROUGH
THE AFTERNOON AND EVENING PERIOD. SNOW WILL BE POSSIBLE OVER MUCH
OF THE REGION...ESP OVER NE WY AND THE NORTHERN BLACK HILLS WITH
MVFR AND POSSIBLE IFR FLIGHT RESTRICTIONS THERE. HAVE ADDED A TREND
TOWARD MVFR AT GCC...WITH RAP EXPECTED TO REMAIN VFR. THE SYSTEM
WILL BRING WINDY CONDITIONS TO THE REGION...ESP IN THE LEE OF THE
BLACK HILLS. HAVE ADDED GUSTY SUSTAINED WINDS AT KRAP TUE EVENING.
.PREV DISCUSSION... /ISSUED 303 PM MST MON JAN 28 2013/
DISCUSSION...WATER VAPOR SHOWS SHARP TROF MOVING INTO THE
ROCKIES...WITH JET ENERGY EJECTING NEWD FROM THE CNTRL ROCKIES
THROUGH THE NRN PLAINS. AT THE SURFACE...LOW CENTER IS DEEPENING
OVER ERN CO WITH LIGHT NLY FLOW ACROSS OUR CWFA. SNOW CONTINUES TO
FALL MAINLY FROM THE BLKHLS EWD.
TONIGHT...BEST LIFT TRANSLATES INTO SCNTRL SD AS NEXT JET STREAK
NOSES THROUGH THE CNTRL PLAINS AND SFC LOW PUSHES EWD ALONG THE
NEB/KS BORDER. STRONG 850-700MB FRONTOGENESIS AND MID LEVEL
INSTABILITY EXPECTED ACROSS SCNTRL SD. 3-5 INCHES OF SNOW
POSSIBLE...ALTHOUGH HIGHER AMOUNTS QUITE POSSIBLE WITHIN HEAVIER
BANDS THAT SET UP. HAVE COVERED WITH A WINTER WX ADVISORY. LIFT/SNOW
SHOULD PUSH EAST OF THE AREA BY DAYBREAK.
TUESDAY...UPPER TROF AXIS SHIFTS INTO THE CNTRL DAKOTAS AS STRONG
SHORTWAVE BEGINS DROPPING DOWN BACK SIDE OF TROF. ARCTIC COLD
FRONT DIVES SOUTHWARD...REACHING NERN WY/WRN SD LATE IN THE DAY.
GUSTY NW WINDS...POSSIBLY REACHING LOWER END ADVISORY ACROSS NWRN
SD...WILL PUSH ACROSS THE AREA TUESDAY AFTN/EVE. WIND CHILLS BY
LATE TUESDAY NIGHT SHOULD DROP UNDER 20 BELOW ZERO ACROSS NWRN SD.
POST FRONTAL LIGHT SNOW/FLURRIES EXPECTED...WITH UPSLOPE
ENHANCEMENT ACROSS THE NRN BLKHLS.
WEDNESDAY...ARCTIC HIGH BUILDS INTO THE DAKOTAS ON
WEDNESDAY...WITH 850-700MB BAROCLINIC ZONE ACROSS NORTHEAST
WYOMING/SOUTHWEST SOUTH DAKOTA. SOME LINGERING LIGHT SNOW/FLURRIES
POSSIBLE...WITH CONTINUING UPSLOPE ENHANCEMENT IN THE NRN BLKHLS.
EXTENDED...ARCTIC AIR WILL HANG AROUND THE AREA ON THURSDAY...
COLDEST NORTH AND EAST OF THE BLACK HILLS...BEFORE BEGINNING TO PUSH
OUT LATE THURSDAY AND THURSDAY NIGHT. LINGERING SNOW IS EXPECTED
ACROSS NORTHEASTERN WY AND FAR WESTERN SOUTH DAKOTA
THURSDAY...ESPECIALLY ACROSS UPSLOPE ENHANCED AREAS OF THE NORTHERN
BLACK HILLS THURSDAY MORNING. SNOW WILL GRADUALLY TAPER OFF THURSDAY
NIGHT...AND EVEN AS LATE AS FRIDAY OVER THE NORTHERN HILLS. THE
ARCTIC BOUNDARY WILL PUSH EAST OF THE AREA FRIDAY BRINGING MUCH
WARMER TEMPERATURES TO THE AREA HEADING INTO THE WEEKEND ALONG WITH
DRY WEATHER.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...WINTER WEATHER ADVISORY UNTIL 6 AM CST TUESDAY FOR MELLETTE-TODD-
TRIPP.
WY...NONE.
&&
$$
SHORT TERM...JOHNSON
EXTENDED...13
AVIATION...JC
UPDATE...JC
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1059 AM CST TUE JAN 29 2013
.DISCUSSION...
/SEE BELOW FOR AVIATION DISCUSSION/
&&
.AVIATION...
PACIFIC FRONT EXTENDED EAST OF AN OZONA...SAN ANGELO...ABILENE...
THROCKMORTON LINE AT 11 AM...MOVING EAST. WEST WINDS WILL INCREASE
RAPIDLY EARLY THIS AFTERNOON...WITH GUSTS OF 40 KTS AT KSJT AND KABI.
WINDS SHOULD DECREASE AFTER 0Z...OR 6 PM. AN ISOLATED THUNDERSTORM
POSSIBLE AT KBBD...KSOA...AND KJCT THIS AFTERNOON. BEST POTENTIAL
WILL BE A KBBD WHERE I WILL INCLUDE A VCTS. VISIBILITIES MAY FALL
SLIGHTLY IN BLOWING DUST LATE THIS AFTERNOON OR EARLY
EVENING...BUT EXPECT THEM TO REMAIN ABOVE 5 SM.
&&
.PREV DISCUSSION... /ISSUED 1000 AM CST TUE JAN 29 2013/
UPDATE...
UPATED TO ADD MORNING THUNDERSTORM FARTHER WEST. INCREASED
TEMPERATURES AND DEW POINTS.
DISCUSSION...
DRYLINE AND SURFACE TROUGH WERE FARTHER WEST THIS MORNING WITH MID
LEVEL CLOUDS PREVENTING MIXING. THUNDERSTORMS WERE DEVELOPING
BETWEEN OZONA AND MERTZON ALONG THE TROUGH. POTENTIAL EXISTS FOR A
STRONG..POSSIBLY EVEN A SEVERE STORM AS THE SURFACE TROUGH MOVES
EAST THROUGH EARLY AFTERNOON...MAINLY ALONG AND EAST AF A SAN ANGELO TO
ABILENE TO THROCKMORTON LINE WITH RUC SFC BASE CAPES OF 1500 TO
1900 J/KG.
04
PREV DISCUSSION... /ISSUED 516 AM CST TUE JAN 29 2013/
AVIATION...
/12Z UPDATE/
VFR CONDITIONS WILL CONTINUE OVER THE NORTHERN TERMINALS THROUGH
THE TAF PERIOD. MVFR CEILINGS OVER THE SOUTHERN TERMINALS WILL
LIFT TO VFR BY NOON...REMAINING VFR FOR THE REMAINDER OF THE TAF
PERIOD. A COLD FRONT WILL MOVE QUICKLY EAST THROUGH THE AREA THIS
MORNING BRINGING HIGH WINDS TO THE TERMINALS. SURFACE WINDS WILL
CONTINUE TO INCREASE IN SPEED THROUGH THE DAY. KABI CAN EXPECT
WESTERLY GUSTS TO OVER 30KT FOR MOST OF THE DAY WITH GUSTS AS HIGH
AS 45KT BY NOON. WINDS AT KSJT WILL GUST TO AROUND 35KT BY NOON.
FOR THE SOUTHERN TERMINALS EXPECT WIND GUSTS FROM 25KT TO 35KT BY
NOON. WINDS WILL DECREASE TO LESS THAN 20KT BY THIS EVENING AT ALL
TERMINALS. BLDU WILL REDUCE VISIBILITIES AT THE NORTHERN
TERMINALS BY NOON TO AROUND 6SM.
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 69 34 56 31 68 / 20 5 0 0 0
SAN ANGELO 70 36 56 27 68 / 20 0 0 0 0
JUNCTION 72 35 59 26 68 / 20 5 0 0 0
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING FROM 2 PM THIS AFTERNOON TO 7 PM CST THIS
EVENING FOR THE FOLLOWING ZONES: BROWN...CALLAHAN...COKE...
COLEMAN...CONCHO...CROCKETT...FISHER...HASKELL...IRION...JONES...
KIMBLE...MENARD...NOLAN...RUNNELS...SCHLEICHER...SHACKELFORD...
STERLING...SUTTON...TAYLOR...THROCKMORTON...TOM GREEN.
WIND ADVISORY UNTIL 7 PM CST THIS EVENING FOR THE FOLLOWING
ZONES: BROWN...CALLAHAN...COKE...COLEMAN...CONCHO...CROCKETT...
FISHER...HASKELL...IRION...JONES...MCCULLOCH...NOLAN...RUNNELS...
SHACKELFORD...STERLING...TAYLOR...THROCKMORTON...TOM GREEN.
&&
$$
99/99/04
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1000 AM CST TUE JAN 29 2013
.UPDATE...
UPATED TO ADD MORNING THUNDERSTORM FARTHER WEST. INCREASED
TEMPERATURES AND DEW POINTS.
&&
.DISCUSSION...
DRYLINE AND SURFACE TROUGH WERE FARTHER WEST THIS MORNING WITH MID
LEVEL CLOUDS PREVENTING MIXING. THUNDERSTORMS WERE DEVELOPING
BETWEEN OZONA AND MERTZON ALONG THE TROUGH. POTENTIAL EXISTS FOR A
STRONG..POSSIBLY EVEN A SEVERE STORM AS THE SURFACE TROUGH MOVES
EAST THROUGH EARLY AFTERNOON...MAINLY ALONG AND EAST AF A SAN ANGELO TO
ABILENE TO THROCKMORTON LINE WITH RUC SFC BASE CAPES OF 1500 TO
1900 J/KG.
04
&&
.PREV DISCUSSION... /ISSUED 516 AM CST TUE JAN 29 2013/
AVIATION...
/12Z UPDATE/
VFR CONDITIONS WILL CONTINUE OVER THE NORTHERN TERMINALS THROUGH
THE TAF PERIOD. MVFR CEILINGS OVER THE SOUTHERN TERMINALS WILL
LIFT TO VFR BY NOON...REMAINING VFR FOR THE REMAINDER OF THE TAF
PERIOD. A COLD FRONT WILL MOVE QUICKLY EAST THROUGH THE AREA THIS
MORNING BRINGING HIGH WINDS TO THE TERMINALS. SURFACE WINDS WILL
CONTINUE TO INCREASE IN SPEED THROUGH THE DAY. KABI CAN EXPECT
WESTERLY GUSTS TO OVER 30KT FOR MOST OF THE DAY WITH GUSTS AS HIGH
AS 45KT BY NOON. WINDS AT KSJT WILL GUST TO AROUND 35KT BY NOON.
FOR THE SOUTHERN TERMINALS EXPECT WIND GUSTS FROM 25KT TO 35KT BY
NOON. WINDS WILL DECREASE TO LESS THAN 20KT BY THIS EVENING AT ALL
TERMINALS. BLDU WILL REDUCE VISIBILITIES AT THE NORTHERN
TERMINALS BY NOON TO AROUND 6SM.
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 69 34 56 31 68 / 20 5 0 0 0
SAN ANGELO 70 36 56 27 68 / 20 0 0 0 0
JUNCTION 72 35 59 26 68 / 20 5 0 0 0
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING FROM 2 PM THIS AFTERNOON TO 7 PM CST THIS
EVENING FOR THE FOLLOWING ZONES: BROWN...CALLAHAN...COKE...
COLEMAN...CONCHO...CROCKETT...FISHER...HASKELL...IRION...JONES...
KIMBLE...MENARD...NOLAN...RUNNELS...SCHLEICHER...SHACKELFORD...
STERLING...SUTTON...TAYLOR...THROCKMORTON...TOM GREEN.
WIND ADVISORY UNTIL 7 PM CST THIS EVENING FOR THE FOLLOWING
ZONES: BROWN...CALLAHAN...COKE...COLEMAN...CONCHO...CROCKETT...
FISHER...HASKELL...IRION...JONES...MCCULLOCH...NOLAN...RUNNELS...
SHACKELFORD...STERLING...TAYLOR...THROCKMORTON...TOM GREEN.
&&
$$
99/99
AREA FORECAST DISCUSSION
NWS SPOKANE WA
1023 AM PST Tue Jan 29 2013
.SYNOPSIS...
The weather pattern will remain active and wintry through Thursday
as a number of storm systems will result in periodic heavy snow
accumulations. There will be a break in the weather today...however
another extended snow event looks likely for the region with the
focus of the heavier snow again for the higher terrain of the
Central Idaho Panhandle...the Blue mountains and the Camas
Prairie. High pressure will build into the region at the end of
the work week and linger into the weekend with fog and low
stratus expected across much of the basin and in the valleys.
&&
.DISCUSSION...
rest of today...Looks like round two of the recent winter events
has generally wound down this morning. Radar no longer detecting
any precipitation over the Inland NW...while local webcams and
mesonet not detecting any either. Satellite was showing that much
of the mid and high level cloudiness has departed south and east
of the forecast area...with little upstream at this time. With a
dried out dendritic layer...there is little chance of additional
significant snow through the remainder of the day. Given current
trends and observations we have ended the winter weather
highlights for the Camas Prairie and Blue Mountains. Although both
locations could see some showers later today...additional
accumulations will be light. For the remainder of the forecast
area...the main changes revolved around lowering the sky cover
through the afternoon. The latest visible satellite imagery was
showing large holes in the high overcast...with the main cloud
cover now being attributed to low stratus across portions of NE
Washington and N Idaho. Clouds will increase once again late this
afternoon...as the next winter disturbance rounds the top of the
ridge and drops into the north Cascades via British Columbia. fx
&&
.AVIATION...
18Z TAFS: main trouble spots this morning are along the KGEG-KCOE
corridor due to areas of stratus and IFR cigs. Feel confident that
these should be mainly gone before 20-21z...with VFR conditions
after that. All remaining sites should be VFR through the daytime
hours. For tonight...the next winter system will come into play.
The latest HRRR has delayed the onset of the pcpn until aft 04z
for all sites xcp MWH and EAT. Feel confident that the pcpn will
be -sn for all sites xcp LWS and that IFR conditions will ensue
shortly after the onset of pcpn. Looks like the eastern sites
should see abt 6hrs of pcpn...aft which the main concern will be
widespread stratus and fog. MOS guidance is suggesting IFR
conditions for all the eastern sites and we have generally
followed suit. fx
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 33 26 36 30 36 27 / 10 70 40 30 40 30
Coeur d`Alene 33 26 35 31 36 28 / 10 70 50 50 70 40
Pullman 36 27 39 33 39 30 / 10 70 70 70 60 50
Lewiston 43 32 44 37 46 32 / 10 70 70 70 60 40
Colville 34 25 35 30 41 26 / 10 60 20 20 30 30
Sandpoint 34 26 34 28 36 28 / 10 70 60 60 70 60
Kellogg 32 25 35 30 39 29 / 20 80 80 80 80 70
Moses Lake 39 28 41 29 41 27 / 0 10 10 10 10 10
Wenatchee 36 28 38 29 39 27 / 0 20 10 10 10 10
Omak 34 24 31 24 36 25 / 10 40 10 10 10 10
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1130 PM MST WED JAN 30 2013
.UPDATE...
ISSUED AT 1130 PM MST WED JAN 30 2013
BASED ON RADAR AND SATELLITE OBSERVATIONS...THE PERSISTENT SNOW
BANDS THAT BROUGHT SNOW TO THE I-70 CORRIDOR HAVE SHIFTED EASTWARD
WITH CONDITIONS IMPROVING FROM RIFLE TO SILT BASED ON OBSERVATIONS
AND WEBCAMS. THIS IS CONSISTENT WITH THE LATEST RAP DATA SHOWING
LITTLE IF ANY ADDITIONAL ACCUMULATIONS HERE. THEREFORE CANCELLED
THE WINTER WEATHER ADVISORY FOR COZ007. WEBCAMS AND RADAR STILL
SHOW SNOW BANDS STREAMING ACROSS THE FLATTOPS...THE I-70 CORRIDOR
FROM GLENWOOD SPRINGS TO VAIL PASS...AND STEAMBOAT. REMAINING
HIGHLITES LOOK ON TRACK.
UPDATE ISSUED AT 536 PM MST WED JAN 30 2013
PERSISTENT SNOW OVER THE I-70 CORRIDOR WEST OF EAGLE AND EAST OF
PALISADE HAD ALREADY BROUGHT 1 TO 2 INCHES OF SNOW TO THESE AREAS
EARLY THIS EVENING. LATEST NAM12 AND RAP13 DATA INDICATED THIS
PERSISTENT BAND OF SNOW COULD LAST THROUGH THE EVENING BRINGING
FROM 2 TO 5 INCHES OF BY EARLY MORNING. THEREFORE...A WINTER
WEATHER ADVISORY HAS BEEN ISSUED ZONES 7 AND 8. AREAS IN ZONE 8
ARE NOT INCLUDED IN THIS ADVISORY.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 302 PM MST WED JAN 30 2013
SNOW AND WIND IMPACTING THE NERN PART OF THE FORECAST AREA TODAY.
CLASSIC OROGRAPHIC SNOW IN NORTHWEST FLOW AS PACIFIC MOISTURE
AND STRONG JET TARGETS THE PARK/GORE RANGES AND THE FLAT TOP
MOUNTAINS. MT WERNER SENSORS SHOW WIND OF 25 MPH BUT GUSTS TO
AROUND 40 MPH. GIVEN LOW SNOW TO LIQUID RATIO VALUES...WEB CAMS SHOWING
POOR VISIBILITY OVER THE MOUNTAIN PASSES. SNOTEL SITES SHOWING 6
HOUR QPF GENERALLY RANGING FROM /0.20/ TO /0.50/ INCHES...BUT THIS
MAY EQUATE TO 5 TO 13 INCHES OF SNOW IF LIQUID TO WATER RATIO IS
AROUND 25:1 OR HIGHER. THE HEAVIEST SNOW APPEARS CONFINED ABOVE
8500 FEET...OBSERVATIONS FROM THE PUBLIC AND SPOTTER REPORTS
SUGGEST ONLY LIGHT SNOW IN THE MOUNTAIN VALLEYS (FROM MARBLE AND
ASPEN).
MODEL DATA KEEPS MOISTURE STREAM AND OROGRAPHIC SNOW ONGOING
THROUGH THE NIGHT...BUT GRADUALLY TAPERS OFF ON THURSDAY. GRADIENT FLOW
DOES WEAKEN ON THURSDAY WITH MOISTURE STREAM SOMEWHAT WEAKER...THEREFORE
EXPECT SNOWFALL RATES TO DIMINISH ON THURSDAY. NO CHANGES TO THE
CURRENT WINTER STORM WARNINGS AS ACCUMULATING SNOWFALL COMBINED
WITH WIND WILL PERSIST INTO THURSDAY. IN ADDITION...AN EMBEDDED
DISTURBANCE IN NORTHWEST FLOW RACES ACROSS THE NRN DIVIDE MOUNTAINS
LATE THURSDAY AFTERNOON. ONCE THIS SHORT WAVE CROSSES THE
DIVIDE...EXPECT SNOW AND WIND TO TAPER OFF CONSIDERABLY.
FOR THE REMAINDER OF THE FORECAST AREA...MUCH OF EASTERN UTAH AND
EXTREME WRN COLORADO WILL BE DRY. EXTENSIVE CLOUD COVER THAT
COVERS MUCH OF THE REGION TODAY WILL GRADUALLY ERODE AWAY. MORE
SUN EXPECTED ON THURSDAY ACROSS THE SWRN HALF OF THE FORECAST
AREA. WITH LESS CLOUD COVER... EXPECT OVERNIGHT TEMPS ON FRIDAY
MORNING TO BE THE COLDEST OF THE WEEK FOR THE NRN AND CENTRAL
VALLEYS.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 302 PM MST WED JAN 30 2013
A WAVE IN NW FLOW WILL CLIP NW CO FRI AS IT MOVES INTO THE PLAINS.
THE GFS/ECMWF/CANADIAN MODELS IN GENERAL AGREEMENT HERE AND HAVE
BOOSTED POPS FOR THE ELKHEAD AND PARK RANGES BASED ON THIS. A PERIOD
OF Q-FORCING ALOFT WITH WARM ADVECTIVE UPLIFT AT MTN TOP LEVEL AND
WITH W-NW OROGRAPHICS SHOULD RESULT IN SOME AREAS OF SNOW FROM ABOUT
MIDDAY FRI INTO FRI EVENING.
THIS WEEKEND LOOKS DRY AS THE WEST COAST RIDGE SLIDES OVER THE
FORECAST AREA. A SMALL CLOSED LOW CURRENTLY DEVELOPING OFF THE CA
COAST IS FORECAST TO SHEAR INLAND AND WEAKEN WHILE A LARGER PACIFIC
TROUGH SPLITS AS IT APPROACHES THE COAST. THIS MORNING/S MODELS WERE
IN GENERAL AGREEMENT WITH TAKING THE SOUTHERN PORTION OF THE SPLIT
AND FORMING A CUT-OFF LOW WELL OFF THE CA COAST...WHILE THE NORTHERN
SPLIT BRUSHES OUR FORECAST ABOUT SUNDAY. NEITHER THE GFS NOR ECMWF
SHOW MUCH CHANCE OF SIGNIFICANT PRECIPITATION THOUGH FROM THE
NORTHERN WAVE THOUGH.
GFS HAS BEEN INCONSISTENT HANDLING THE SOUTHERN SPLIT CUT-OFF
LOW...ALTERNATING BETWEEN BRINGING TO ABOUT THE 4 CORNERS BY TUE AND
KEEPING IT OFFSHORE INLINE WITH THE MORE CONSISTENT ECMWF. FOLLOWING
MORE THE PREFERRED ECMWF WOULD RESULT IN GENERAL RIDGING OVER ERN
UT/WRN CO EARLY NEXT WEEK AND A MINIMAL CHANCE OF PRECIP. BUT BOTH
THE GFS AND ECMWF SHOW A DECENT TROUGH APPROACHING THE PACIFIC NW
COASTLINE ON WEDNESDAY...FOR POTENTIALLY UNSETTLED WEATHER LATE NEXT
WEEK.
TEMPERATURES ARE EXPECTED TO GRADUALLY MODERATE THIS PERIOD ALTHOUGH
TEMPS WILL STILL BE A BIT OF A CHALLENGE IN MANY VALLEYS. SNOW
COVER WILL KEEP TEMPS IN THE EASTERN UINTA BASIN LAGGING THE MOST
BEHIND...HOWEVER...WHERE AN INVERSION SHOULD BE SLOW TO ERODE. INVERSIONS
WILL NOT BE A STRONG FOR THE GRAND VALLEY WHERE SNOW COVER IS
DIMINISHING IN AREAL EXTENT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1015 PM MST WED JAN 30 2013
A PERSISTENT MOIST NORTHWEST FLOW WILL CONTINUE TO DELIVER SNOW TO
THE NORTHERN AND CENTRAL MOUNTAINS AND ADJACENT VALLEYS DURING THE
REMAINDER OF THE NIGHT. AS A RESULT...EXPECT KSBS AND KASE TO HAVE
PERSISTENT MVFR CIGS AND VSBY WITH OCCASIONAL IFR CONDITIONS DURING
MUCH OF THE REMAINDER OF THE NIGHT WITH SURROUNDING MOUNTAINS
OBSCURED IN SNOW. KRIL...KGWS...AND KGUC WILL HAVE OCCASIONAL
MVFR CIGS AND VSBY IN SNOW SHOWERS THROUGH 12Z THURSDAY.
MODELS CONTINUE TO GENERATE MOUNTAIN SNOW OVER THE NORTHERN AND
CENTRAL MOUNTAINS THURSDAY THROUGH MIDNIGHT...THOUGH LIGHTER IN
INTENSITY AND LESS EXTENSIVE. ADJACENT TERMINALS ARE UNLIKELY TO
DROP BELOW VFR CONDITIONS THURSDAY.
AREAS WEST OF A KPSO TO KCAG LINE WILL HAVE VFR CONDITIONS THROUGH
THE NEXT 24 HOURS.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...WINTER WEATHER ADVISORY UNTIL 2 AM MST THURSDAY FOR COZ008.
WINTER STORM WARNING UNTIL 6 PM MST THURSDAY FOR COZ004-005-010-
013.
UT...NONE.
&&
$$
UPDATE...MDA
SHORT TERM...PF
LONG TERM...JAD
AVIATION...NL
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1000 PM MST WED JAN 30 2013
.UPDATE...NO CHANGES NEED TO THE CURRENT FORECAST. WINDS CONTINUE
TO BLOW OVER THE MOUNTAINS AND FOOTHILLS WITH GUSTS IN THE 40 TO
60 MPH RANGE...WITH BERTHOUD PASS JUST GUSTING TO 65 MPH. SNOTEL
OBSERVATIONS STILL SHOWING THE OROGRAPHIC SNOW PRODUCTION...WITH
AREAS RECEIVING BETWEEN HALF AN INCH TO UP TO AN INCH AN HOUR WITH
THE HIGHEST AMOUNTS NEAR RABBIT EARS PASS. WINTER STORM WARNING
STILL IN EFFECT UNTIL THURSDAY EVENING. SOME OF THE LATEST MODELS
ARE SHOWING LESS MOISTURE UPSTREAM...SO THE ENDING TIME OF THE
WARNING MAY HAVE TO BE ADJUSTED. HOWEVER...THE WIND WILL CONTINUE
TO BE QUITE STRONG TO CONTRIBUTE TO THE HAZARDOUS WEATHER.
&&
.AVIATION...SOUTHWEST WILL PREVAIL TONIGHT AT DEN AND APA AS
DRAINAGE FLOW DEVELOPS WITH SPEEDS AROUND 12 KTS. WINDS TO REMAIN
WEST TO NORTHWEST AT BJC THROUGH THE EVENING AND OVERNIGHT...WITH
SOME GUSTS TO 40 KTS POSSIBLE AFTER 06Z. ON THURSDAY...WINDS
TO BECOME NORTHWEST AND WEAKEN ACROSS THE AREA AFTER 16Z. SOME
GUSTS TO 25 KTS WILL BE POSSIBLE AT BJC. VFR TO PREVAIL.
&&
.PREV DISCUSSION... /ISSUED 355 PM MST WED JAN 30 2013/
SHORT TERM...STRONG NORTHWEST FLOW ALOFT OVER AREA WITH
OROGRAPHICS CONTINUING ACROSS MOUNTAINS. WEB CAMS INDICATE SNOW
CONTINUING ACROSS MOUNTAINS...THOUGH HAS SHOWN SOME SIGNS OF
DECREASING DURING THE PAST FEW HOURS. STABILITY HAS BEEN
LIMITED...WHICH HAS HINDERED THE HEAVIER SNOW RATES. STILL..WINDS
BEEN QUITE GUSTY ACROSS THE RIDGES...WITH A RECENT GUST TO 71 MPH
ATOP BERTHOUD PASS WHILE OTHER GUSTS WERE MAINLY IN THE 50S. THE
WINDS WERE CREATING AREAS OF BLOWING SNOW ACROSS THE MOUNTAIN
PASSES. GUSTY WINDS ALSO OCCURRING IN AND NEAR FOOTHILLS WITH
GUSTS MAINLY IN THE 40S. ACROSS PLAINS WEAK MESOCYCLONE SLIDING
SOUTH ACROSS MORGAN COUNTY KEEPING GUSTY WINDS FROM SPREADING EAST
ACROSS URBAN CORRIDOR. FLOW ALOFT REMAINS STRONG TONIGHT AND
INCREASES SLIGHTLY AS SHOWN BY RAP CROSS SECTIONS. AIRMASS TO
REMAIN QUITE MOIST ACROSS THE MOUNTAINS ALONG WITH CONTINUED
OROGRAPHICS AND SNOWFALL. STABILITY SHOULD IMPROVE OVERNIGHT...
HELPING WITH SNOWFALL RATES. ADDITIONAL 3 TO 6 INCHES STILL
POSSIBLE ON FAVORED WEST FACING SLOPES WITH LESSER AMOUNTS
ELSEWHERE. MODEL CROSS SECTIONS SHOW WEAK MOUNTAIN WAVE DEVELOPING
OVERNIGHT WHICH WILL HELP TO INCREASE WINDS. GUSTS AROUND 70 MPH
POSSIBLE ALONG THE HIGHER RIDGES...WITH GUSTS UP TO 60 MPH ALONG
THE FOOTHILLS. THE GUSTY WINDS WILL CONTINUE TO CREATE CONSIDERABLE
BLOWING SNOW OVER THE MOUNTAIN PASSES WITH POSSIBLE WHITE OUT
CONDITIONS ABOVE TIMBERLINE. ACROSS PLAINS...WINDS TO BE A BIT
GUSTY NEAR THE FOOTHILLS AND WYOMING BORDER WITH LESS WIND
ELSEWHERE. MODELS CONTINUE TO SHOW AN AREA OF LIGHT SNOW
DEVELOPING ALONG THE WYOMING BORDER TONIGHT IN VICINITY OF UPPER
JET. OTHERWISE...DRY CONDITIONS TO PREVAIL. ON THURSDAY...STRONG
NORTHWEST FLOW ALOFT TO CONTINUE THOUGH MODEL CROSS SECTIONS
INDICATE MOISTURE ACROSS MOUNTAINS DECREASING BY THE AFTERNOON AS
STABILITY INCREASES. STILL DECENT OROGRAPHICS IN PLACE FOR MUCH
OF THE DAY ALONG WITH GUSTY WINDS. SHOULD SEE SNOW GRADUALLY
DECREASE DURING THE DAY THOUGH THERE WILL STILL BE QUITE A BIT OF
BLOWING SNOW. WILL MAINTAIN THE WARNING THROUGH THE DAY THOUGH
ADDITIONAL SNOWFALL SHOULD BE LIGHT. WINDS TO BE A BIT GUSTY IN
AND NEAR THE FOOTHILLS AS A WEAK SURFACE TROUGH IS EXPECTED TO
DEVELOP. FURTHER EAST...MODELS CONTINUE TO SHOW A WEAK COLD FRONT
MOVING INTO THE NORTHEAST CORNER. WITH UPPER JET IN VICINITY...
THERE COULD BE A SLIGHT CHANCE OF LIGHT SNOW IN THE FAR NEAR THE
WYOMING BORDER. OTHERWISE DRY CONDITIONS WILL PREVAIL.
LONG TERM...A RATHER BENIGN WEEK OF WEATHER IS EXPECTED AFTER THE
SNOW SHOWERS CLEAR OUT OF THE MOUNTAINS THURSDAY NIGHT. ON
THURSDAY EVENING...A FEW SNOW SHOWERS MAY BE LINGERING...BUT THEY
WILL BE ON THE DECREASE AS SUBSIDENCE OVER THE STATE INCREASES.
DRY...NORTHWESTERLY FLOW ALOFT IS FORECAST TO CONTINUE THROUGH
THE PERIOD AS AN UPPER RIDGE REMAINS ANCHORED OFF THE WEST COAST
AND A DEEP TROUGH CONTINUES OVER THE EASTERN UNITED STATES. THE
ECMWF AND GFS ARE IN GOOD AGREEMENT THROUGH THE WEEKEND...BUT AT
THE END THE TWO MODELS HAVE DIFFERENT IDEAS ABOUT A TROUGH THAT
DEVELOPS OFF THE CALIFORNIA COAST. IF A TROUGH DEVELOPS...IT IS
NOT EXPECTED TO MOVE INTO THE CENTRAL ROCKIES UNTIL THE MIDDLE OF
NEXT WEEK. TEMPERATURES SHOULD GRADUALLY MODERATE THROUGH THE
UPCOMING FORECAST PERIOD AS THE NORTHWEST FLOW ALOFT CONTINUES.
AVIATION... WINDS HAVE BECOME LIGHT NORTHEAST AT DEN DUE TO WEAK
MESOCYCLONE OVER MORGAN COUNTY. GUSTY WEST TO NORTHWEST WINDS
CONTINUE AT APA AND BJC. WINDS TO BECOME NORTHWEST AT DEN BY 00Z
AS MESOCYCLONE SHIFTS EAST INTO WASHINGTON COUNTY. AFTER
03Z...WINDS SHOULD SHIFT TO THE SOUTHWEST AT DEN AND APA AS
DRAINAGE FLOW DEVELOPS WITH SPEEDS AROUND 12 KTS. WINDS TO REMAIN
WEST TO NORTHWEST AT BJC THROUGH THE EVENING AND OVERNIGHT...WITH
SOME GUSTS TO 40 KTS POSSIBLE AFTER 06Z. ON THURSDAY...WINDS
TO BECOME NORTHWEST AND WEAKEN ACROSS THE AREA AFTER 16Z. SOME
GUSTS TO 25 KTS WILL BE POSSIBLE AT BJC. VFR TO PREVAIL.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL 5 PM MST THURSDAY FOR COZ031-033-034.
&&
$$
SHORT TERM...D-L
LONG TERM....DANKERS
UPDATE/AVIATION...KRIEDERMAN
AREA FORECAST DISCUSSION
NWS MIAMI FL
136 AM EST THU JAN 31 2013
.AVIATION...
THE LATEST MODEL GUIDANCE SHOWS A NARROW LINE OF SHOWERS ALONG
THE FRONTAL BOUNDARY APPROACHING THROUGH THE FIRST FEW HOURS OF
THE TAF CYCLE...THROUGH APF BY/AROUND DAYBREAK...THEN THROUGH THE
EAST COAST TERMINALS THROUGH THE EARLY/MID MORNING HOURS. WINDS
WILL SHIFT FROM THE SOUTH TO NORTHWEST WITH THE FROPA. ALTHOUGH A
FEW PERIODS WITH MVFR CIGS CAN`T BE RULED OUT IN AND AROUND ANY
SHOWERS ALONG THE FRONT...MOSTLY VFR CONDITIONS ARE EXPECTED. IN
THE WAKE OF THE FRONTAL BOUNDARY...A STABLE LOW-LEVEL STATUS DECK
WILL LIKELY LINGER THROUGH A GOOD PORTION OF THE DAY BEFORE
GRADUALLY CLEARING.
&&
.PREV DISCUSSION... /ISSUED 855 PM EST WED JAN 30 2013/
UPDATE...
COLD FRONT MOVING THROUGH THE PANHANDLE THIS EVENING WILL APPROACH
SOUTH FLORIDA AFTER MIDNIGHT TONIGHT. LOCAL WRF AND HRRR SHOW A
THIN LINE OF SHOWERS APPROACHING THE NORTHWEST PORTIONS OF THE CWA
AROUND 09Z TONIGHT...AND THEN THE LINE SLOWLY MOVING THROUGH THE
REST OF THE REGION THROUGH THE MORNING HOURS. THE CURRENT POP
GRIDS HANDLE THIS WELL...SO NO UPDATES ARE NEEDED. TEMPERATURES
TONIGHT WILL BE WARM...WITH LOWS NEAR 60 TO THE LOWER 70S.
ALTHOUGH WINDS WILL LIKELY FALL BELOW SCA CRITERION OVER THE
LOCAL GULF WATERS THIS EVENING...KEPT THE SCA GOING AS WINDS WILL
INCREASE LATE TONIGHT BEHIND THE FRONT. FOR THE ATLANTIC
WATERS...WILL CANCEL THE SCA SINCE THE WINDS HAVE FALLEN TO AROUND
10-15 KNOTS AND WINDS ARE NOT EXPECTED TO INCREASE TO SCA
CONDITIONS AGAIN UNTIL AFTER 18Z ON THURSDAY.
PREV DISCUSSION... /ISSUED 628 PM EST WED JAN 30 2013/
AVIATION...VFR WILL PREVAIL, BUT A FEW SHOWERS/BRIEF MVFR WILL BE
POSSIBLE ALONG COLD FRONT EXPECTED TO MOVE ACROSS KAPF AT AROUND
SUNRISE, THEN THE EAST COAST TERMINALS BY MID MORNING THU. CURRENT
WIND OBS ARE SSE BUT ACARS DATA SHOWS SSW JUST ABOVE THE SFC.
VEERED WINDS THROUGH THE NIGHT TO SSW AS FRONT APPROACHES, THEN
TURNED WINDS NW BEHIND THE COLD FRONT THU. GUIDANCE SUGGEST
CLOUDS LIKELY WILL HANG TOUGH BEHIND THE FRONT FOR THE EAST COAST
TERMINALS THROUGHOUT THE DAY THU. BEST PROSPECTS FOR SHOWERS/BRIEF
MVFR CIGS LOOK TO BE 10-15Z THU, EXCEPT 06-12Z AT KAPF. THX CWSU
MIAMI FOR COORDINATION. /GREGORIA
PREV DISCUSSION... /ISSUED 237 PM EST WED JAN 30 2013/
SYNOPSIS...
A COLD FRONT WILL MOVE THROUGH SOUTH FLORIDA THURSDAY
MORNING...ENDING THE ABOVE NORMAL TEMPERATURES AND BRINGING A
SLIGHT CHANCE OF SHOWERS AS IT PASSES. HIGH PRESSURE BUILDS IN
FRIDAY THROUGH THE WEEKEND...WITH SLIGHTLY BELOW NORMAL
TEMPERATURES RISING TO NEAR SEASONAL AVERAGES BY EARLY NEXT WEEK.
SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...
BREEZY CONDITIONS IN PLACE THROUGH FLORIDA AS PRESSURE GRADIENT
BETWEEN THE SUBTROPICAL RIDGE OVER WESTERN ATLANTIC AND SURFACE
COLD FRONT MOVING EASTWARD THROUGH THE DEEP SOUTH INCREASES. SOUTH
WINDS HAVE GUSTED TO NEAR 30 KTS...JUST BELOW WIND ADVISORY
CRITERION. GUSTS MAY DIURNALLY DIMINISH SLIGHTLY...BUT REMAIN HIGH
ENOUGH TO PRECLUDE ANY FOG FORMATION TONIGHT. TEMPERATURES AHEAD
OF THE FRONT CONTINUE TO BE ABOVE NORMAL...WITH READINGS NEAR 80F
ACROSS MOST OF SOUTH FLORIDA.
MODELS HAVE TRENDED A BIT SLOWER FOR FROPA FOR SOUTH FLORIDA. THE
SFC FRONT LOCATED NEAR KPNS NOW WILL TREK ACROSS THE PANHANDLE
THIS EVENING...THEN APPROACH I-4 CORRIDOR OVERNIGHT. IT IS NOT
EXPECTED TO INTRUDE ON NORTHWEST SECTIONS OF OUR CWA UNTIL AROUND
SUNRISE. THUS...WARM AND FAIRLY BREEZY NIGHT IS IN STORE. MINIMA
WILL RANGE FROM AROUND 60F NORTHWEST INTERIOR TO AROUND 70F
ATLANTIC METROS. THE COLD FRONT WILL MOVE ACROSS SOUTH FLORIDA
DURING THE MORNING...ACCOMPANIED BY A FEW SHOWERS. DYNAMICAL
FORCING WILL BE NEGLIGIBLE AND ATMOSPHERE WILL REMAIN FAIRLY
STABLE...BUT LOW-LEVEL CONVERGENCE AND DECENT MOISTURE CONTENT
SHOULD BE SUFFICIENT FOR SCATTERED ACTIVITY ALONG AND IN VICINITY
OF SURFACE BOUNDARY. CAA WILL LAG SEVERAL HOURS BEHIND THE
FRONT...SO HIGH TEMPERATURES WILL STILL REACH M/U70S MOST
LOCATIONS.
SKIES CLEAR AND TEMPERATURES PLUMMET THURSDAY NIGHT...AND DESPITE
LACK OF IDEAL RADIATIONAL COOLING CONDITIONS...ADVECTION SHOULD
SUPPORT MINIMA REACHING BELOW 50F FOR MUCH OF THE INTERIOR...AND
SOME 30S ARE POSSIBLE ACROSS COLLIER...GLADES...AND HENDRY COUNTY.
IT APPEARS DRY LOW LEVELS AND NON-ZERO WIND SPEEDS WILL PREVENT
ANY FROST...BUT THIS WILL BE MONITORED. AFOREMENTIONED WINDS
HOWEVER WILL CREATE WIND CHILL VALUES SOME 5-10 DEGREES LOWER THAN
AMBIENT READINGS...LOW ENOUGH TO POSSIBLY REACH ADVISORY
THRESHOLDS ACROSS MAINLY GLADES AND HENDRY COUNTIES.
TEMPERATURES FRIDAY AND FRIDAY NIGHT WILL BE SLIGHTLY BELOW
NORMAL...WITH L70S FOR MAXIMA AND 40S INLAND/50S COASTAL FOR
MINIMA. HIGH PRESSURE BUILDING SOUTH WILL KEEP SKIES CLEAR...AND
NORTH WINDS WILL GRADUALLY BECOME NORTHEAST AND BECOME QUITE LIGHT
OVERNIGHT FRIDAY. TEMPERATURES ATTM APPEAR JUST ABOVE VALUES THAT
WOULD CAUSE FROST CONCERN AND LACK OF WIND SHOULD PRECLUDE ANY
WIND CHILL CONCERNS.
LONG TERM /SATURDAY THROUGH WEDNESDAY/...
THE EXTENDED PERIOD FROM THIS WEEKEND INTO THE MIDDLE OF NEXT WEEK
LOOKS UNEVENTFUL AND DRY AS SEVERAL MID LEVEL TROUGHS MOVE ACROSS
THE NORTHERN STATES MAINTAINING A WEST TO NORTHWEST FLOW OF DRY
AIR OVER THE FLORIDA PENINSULA AND KEEPING THE MID LEVEL RIDGE
SUPPRESSED TO OUR SOUTHEAST. AS THE TROUGHS MOVE TO OUR NORTH,
THIS WILL ALSO REINFORCE THE SURFACE RIDGING ACROSS THE SOUTHEAST
STATES WHICH IN TURN WILL KEEP THE TEMPERATURES CLOSE TO OR
SLIGHTLY BELOW CLIMATOLOGICAL AVERAGES FOR THE BEGINNING OF FEBRUARY.
AVIATION...
GUSTY SOUTHEASTERLY WINDS WILL CONTINUE THROUGH THE TAF PERIOD AT
ALL SITES. FROPA IS STILL EXPECTED ACROSS THE EAST COAST TERMINALS
BETWEEN 10Z-13Z ACCOMPANIED BY SCATTERED SHOWERS. BRIEF PERIODS OF
MVFR CIGS WILL LIKELY ACCOMPANY ANY SHOWER ACTIVITY BUT SHOULD NOT
BE LONG ENOUGH TO PREVAIL IN THE TAF. WINDS WILL TURN AROUND TO
THE NORTHWEST BEHIND THE FRONT AND REMAIN AT AROUND 10 KNOTS.
MARINE...
WINDS NEAR 20 KTS WITH SOUTHERLY GUSTS TO NEAR 30 KTS WARRANTED
ISSUANCE OF SMALL CRAFT ADVISORY EARLY TODAY...AND THIS WILL
REMAIN IN EFFECT FOR ALL MARINE ZONES OVERNIGHT. STRONG WINDS
BEING INDUCED BY TIGHT PRESSURE GRADIENT IN ADVANCE OF QUICK-
MOVING COLD FRONT. THIS FRONT WILL PASS THROUGH EARLY
FRIDAY...WITH NORTH WINDS LIKELY EXCEEDING ADVISORY THRESHOLD
BEHIND IT. STRONG WINDS AND BUILDING SEAS WILL IMPACT THE WATERS
THURSDAY NIGHT THROUGH AT LEAST FRIDAY...BEFORE SUBSIDING AS HIGH
PRESSURE BUILDS OVERHEAD.
FIRE WEATHER...
NO FIRE WEATHER CONCERNS TODAY. A COLD FRONT WILL RACE THROUGH
SOUTH FLORIDA THURSDAY MORNING...WITH MUCH DRIER AIR MOVING IN IN
ITS WAKE. RELATIVE HUMIDITY VALUES MAY DROP TO NEAR 35 PERCENT
THURSDAY AFTERNOON ACROSS GLADES AND HENDRY COUNTIES AND NORTH
WINDS WILL BE 10 TO 15 MPH OR HIGHER. FORECAST CONDITIONS DONT
SUPPORT ISSUANCE OF FIRE WEATHER WATCH...BUT A FIRE DANGER
STATEMENT HAS BEEN ISSUED THURSDAY. RELATIVE HUMIDITY WILL BE
VERY LOW FRIDAY...BUT WINDS WILL SUBSIDE A BIT. STILL...FIRE
WEATHER HEADLINES ARE LIKELY ON FRIDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 75 52 71 54 / 30 - 0 0
FORT LAUDERDALE 79 56 72 60 / 30 - 0 0
MIAMI 80 57 72 59 / 20 - 0 0
NAPLES 71 46 71 49 / 20 - 0 0
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR COASTAL
WATERS FROM CHOKOLOSKEE TO BONITA BEACH, FL OUT 20 NM-
COASTAL WATERS FROM EAST CAPE SABLE TO CHOKOLOSKEE, FL OUT
20 NM-GULF WATERS FROM CHOKOLOSKEE TO BONITA BEACH, FL
EXTENDING FROM 20 TO 60 NM.
&&
$$
DISCUSSION/MARINE/FIRE...30/KOB
AVIATION/RADAR...85/AG
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1156 PM EST WED JAN 30 2013
.UPDATE...
ISSUED AT 1012 PM EST WED JAN 30 2013
ALL HEADLINES THAT END THIS EVENING HAVE BEEN ALLOWED TO EXPIRE AS
SCHEDULED. ATTENTION NOW TURNS TO LAKE ENHANCED/LAKE EFFECT SNOW AS
COLDER AIR CONTINUES TO FLOW INTO THE AREA BEHIND DEPARTING STORM
SYSTEM. KMQT RADAR HAS SHOWN A NICE EXPANSION OF HVY SNOW BANDS OFF
LAKE SUPERIOR THIS EVENING UNDER LINGERING DEEP MOISTURE/CAA...AND
VAD WIND PROFILE SHOWS NEARLY UNIDIRECTIONAL NORTHERLY WINDS TO
11KFT MSL. THERE ARE CONFLICTING SIGNALS ON HOW MUCH THE WIND MAY
BACK OVERNIGHT AS LOCAL HIGH RES-WRF MAINTAINS A MORE NRLY WIND INTO
NCNTRL UPPER MI WHILE NAM BACKS WIND MORE NW. GIVEN TRENDS IN HRLY
RUC RAPID REFRESH RUNS TO SLOW THE BACKING...OPTED TO EXTEND WARNING
FOR MARQUETTE COUNTY UNTIL 11Z. WITH RATHER PERSISTENT HVY SNOW
OCCURRING AT THE OFFICE THIS EVENING AND RADAR IMAGERY SHOWING
EXPANSION OF HVY SNOW BANDS...WOULD NOT BE SURPRISED TO SEE SOME
LOCALIZED ACCUMULATIONS OVER 1 FOOT DURING THE NIGHT IN THE HIGHER
TERRAIN BETWEEN BIG BAY...NEGAUNEE...GWINN AND SKANDIA. THIS HVY
SNOW WILL ALSO TARGET WRN ALGER COUNTY WEST OF SHINGLETON. WHILE
WARNING FOR ALGER/LUCE/NRN SCHOOLCRAFT ONLY GOES TO 12Z...WILL LET
MID SHIFT TAKE A LOOK AT REPLACEMENT WITH A LONGER DURATION LAKE
EFFECT SNOW ADVY OR WARNING FOR THAT AREA.
TO THE W...NO CHANGES WERE MADE TO THE GOGEBIC/ONTONAGON ADVY. OVER
THE KEWEENAW...COLD AIR WILL PUSH THE DGZ DOWN TO NEAR THE SFC...
RESULTING IN SMALL SNOWFLAKES THAT ARE VERY EFFECTIVE AT REDUCING
VIS. WHILE ACCUMULATIONS WILL PROBABLY ONLY BE IN THE 2-4 INCH
RANGE/12HRS AT MOST LOCATIONS...VERY LOW VIS DURING -SHSN ALONG WITH
OCNL BLSN SUGGEST AN ADVY HEADLINE IS WARRANTED FOR KEWEENAW/NRN
HOUGHTON AS DRIVING WILL BE DIFFICULT AT TIMES.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 441 PM EST WED JAN 30 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH FROM
HUDSON BAY AND NW ONTARIO THROUGH MN/IA INTO ERN OK. THE POTENT
SHORTWAVE TROUGH OVER SW WI AND ASSOCIATED DEFORMATION ZONE
CONTINUED TO SUPPORT A HEAVY SNOW BAND FROM ERN WI INTO THE E HALF
OF UPPER MI. LIGHTER SNOW WAS OBSERVED OVER THE WEST HALF OF UPPER
MI. SNOW TOTALS OF AROUND 6 INCHES WERE OBSERVED BY 21Z FROM THE NWS
MQT OFFICE TO MNM...GLADSTONE AND MANISTIQUE. A TIGHT GRADIENT BTWN
THE 987 MB LOW OVER SRN LOWER MI AND ARCTIC HIGH PRES BUILDING INTO
THE PLAINS HAS RESULTED IN GALES ACROSS LAKE SUPERIOR AND GUSTY N
WINDS TO 30 MPH OVER MOST OF THE CWA.
TONIGHT AND THURSDAY...THE HEAVY SNOW BAND WHICH CORRELATED WELL WITH
NAM/RUC 700-600 MB FGEN IS EXPECTED TO SHIF QUICKLY TO THE NORTHEAST
THIS EVENING LEAVING MAINLY LIGHT SNOW THAT WILL DIMINISH BTWN
00Z-03Z. HOWEVER...COLDER AIR MOVING IN ON THE STRONG N WINDS
COMBINED WITH 850 MB TEMPS TO AROUND -15C WILL CONTINUE TO SUPPORT
LCLY HIGHER SNOWFALL RATES N CNTRL...ESPECIALLY VCTY MARQUETTE THIS
EVENING WITH CYCLONIC LOW LEVEL 340-350 WIND DIRECTION NEAR THE
SHORE. FAVORABLE UPSLOPE NRLY FLOW INTO THE FAR WEST SHOULD ALSO
BRING INCREASING LES INTO IWD. RADAR TRENDS AND MODELS SUGGEST
ADDITIONAL SYNOPTIC SNOW POTENTIAL IN THE 1 TO 3 INCH RANGE BTWN 21Z-
03Z. HOWEVER AREAS WITH LAKE CONTRIBUTION COULD SEE ANOTHER 3 TO 6
INCHES THROUGH 12Z/THU.
AS THE STRONGER SYNOPTIC FORCING WITH THE SHRTWV MOVES OUT THIS
EVENING...HEADLINES ARE SET TO EXPIRE BY AROUND 03Z OVER THE S CWA.
A TRANSISTION TO LAKE EFFECT SNOW WILL CONTINUE OVERNIGHT WITH
FAVORABLE CONDITION PERSISTING INTO THURSDAY. ANOTHER TRAILING
SHRTWV SLIDING SE INTO THE UPPER LAKES WILL MAINTAIN 850-700 MB
MOISTURE AND INVERSION HEIGHTS AOA 10K FT. WITH THE WINDS BACKING
SLIGHTLY TO 340-330 THE HEAVIER LES WILL CONTINUE TO FOCUS INTO THE
FAR WEST AND TO AREAS EAST OF MARQUETTE. 850 MB TEMPS FALLING TO
AROUND -20C MAY SHRINK THE DGZ LAYER INTO THE 1K-3K RANGE BUT STILL
SHOULD BE SUFFICIENT FOR LSR VALUES CLOSE TO 25/1. ADDITIONAL
SNOWFALL AMOUNTS OF 3 TO 7 INCHES ARE POSSIBLE.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 441 PM EST WED JAN 30 2013
MODELS ARE IN GOOD GENERAL AGREEMENT THROUGH THE EXTENDED WITH DEEP
UPPER TROUGH STARTING THE PERIOD FRI AND GRADUALLY BREAKING DOWN AND
SHIFTING WEST THROUGH NEXT WED...AS AN UPPER RIDGE MOVES INTO THE
WRN CONUS.
GOOD NW WIND LES WILL BE ONGOING INTO THU NIGHT GIVEN NW LOW LEVEL
FLOW...AMPLE MOISTURE AND 825MB INVERSION TOP TEMPS AROUND -25C.
LATE THU NIGHT AND FRI...A SFC HIGH WILL MOVE S OF THE CWA WHILE A
SHORTWAVE TROUGH DIVES IN FROM THE NW FORMING A MESO-LOW OVER ERN
LAKE SUPERIOR LATE FRI. THIS TURNS THE NW WINDS WLY BY FRI
AFTERNOON...FOCUSING LES OVER THE KEWEENAW AND FAR NE UPPER MI.
PRIOR WIND SHIFT...THE BEST LES WILL BE FOCUSED OVER ONTONAGON AND
GOGEBIC COUNTIES AND OVER ERN UPPER MI FROM MUNISING TO GRAND
MARAIS. LES SHOULD INITIALLY WEAKEN SOME LATE THU NIGHT AS RIDGING
MOVES INTO THE AREA...BUT WILL GET A BOOST FROM THE SHORTWAVE LATER
ON FRIDAY. THERE IS ALREADY A LES ADVISORY FOR ONTONAGON/GOGEBIC
COUNTIES THROUGH THU NIGHT...AND THAT STILL LOOKS FINE. BUT WILL
LIKELY ALSO NEED HEADLINES FOR THE ERN U.P. THU NIGHT INTO FRI. THE
KEWEENAW MAY ALSO NEED HEADLINES FRI INTO FRI NIGHT. WILL NOT ISSUE
ANY NEW HEADLINES AT THIS POINT GIVEN HEADLINES ALREADY IN EFFECT
OVER THE ERN U.P. AND SOME UNCERTAINTY AS TO THE RESIDENCE TIME AND
INTENSITY OF ANY STRONGER BANDS THAT MOVE ACROSS THE KEWEENAW.
THU NIGHT THROUGH FRI NIGHT LOOKS TO BE THE COLDEST PERIOD OF THE
NEXT WEEK. LOWS THU NIGHT AND FRI NIGHT LOOKS TO FALL TO THE TEENS
BELOW ZERO WITH WIND CHILLS TO -35F OVER PARTS OF THE INTERIOR.
HIGHS ON FRI LOOK TO BE AROUND ZERO OVER THE INTERIOR W...AND IN THE
LOW TEENS ABOVE ZERO E. WIND CHILL VALUES ARE CURRENTLY FORECAST TO
BE IN TEENS BELOW ZERO AT THE WARMEST FRI AFTERNOON OVER THE
INTERIOR W...AND IN THE SINGLE DIGITS BELOW ZERO E. WILL LIKELY NEED
SOME WIND CHILL ADVISORY HEADLINES UP WHERE THERE ARE NO OTHER
WINTER WX HEADLINES.
MODELS IN RELATIVELY GOOD AGREEMENT WITH A CLIPPER SHORTWAVE MOVING
THROUGH LATE SAT INTO EARLY SAT NIGHT...BUT ONLY MINOR SYNOPTIC SNOW
ACCUMULATIONS AND INCREASED NW WIND LES ARE EXPECTED TO RESULT FROM
THE SYSTEM.
SFC RIDGING MOVES OVER ON SUN AHEAD OF THE NEXT...STRONGER...CLIPPER
SYSTEM THAT MODEL DEPICT MOVING THROUGH. ALTHOUGH MODELS SEEM TO
AGREE FAIRLY WELL ON THE OVERALL TRACK AND INTENSITY OF THE
SYSTEM...THE 00Z/30 ECMWF IS 6-12 HOURS FASTER THAN THE 12Z/30 GFS.
SEVERAL INCHES OF SNOW MAY RESULT AREA WIDE FROM THIS SYSTEM.
MODELS THEN INDICATE...WITH GREATER UNCERTAINTY...ANOTHER CLIPPER
SYSTEM MOVING THROUGH SOMETIME MIDWEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1155 PM EST WED JAN 30 2013
AT KIWD...LAKE EFFECT -SHSN WILL INCREASE OVERNIGHT AS COLDER AIR
FLOWS INTO THE AREA AND LOW-LEVEL WINDS BECOME MORE CONVERGENT INTO
WRN UPPER MI. AS A RESULT...IFR CONDITIONS SHOULD GENERALLY PREVAIL
AT KIWD THRU TODAY. SOME IMPROVEMENT IS POSSIBLE THIS EVENING AS WINDS
BEGIN TO BACK...POSSIBLY SHIFTING -SHSN N OF KIWD. AT KCMX...IFR
CONDITIONS SHOULD PREVAIL OVERNIGHT AS LAKE EFFECT -SHSN CONTINUE
UNDER INCREASINGLY COLDER AIR MASS. WITH THE COLDER AIR...SNOWFLAKE
SIZE WILL BECOME SMALLER AND VERY EFFECTIVE AT KEEPING VIS LOW.
COMBINATION OF SNOW AND SOME BLSN WILL LIKELY RESULT IN LIFR
CONDITIONS FOR MUCH OF THE DAY INTO THE EVENING AT KCMX. AT KSAW...
LAKE EFFECT SHSN UNDER NORTHERLY WINDS SHOULD LEAD TO IFR/LIFR
CONDITIONS FOR THE NEXT SEVERAL HRS. AS WINDS BACK AND PUSH HEAVIER
LAKE EFFECT SHSN TO THE E...EXPECT IMPROVEMENT TO MVFR EARLY IN THE
MORNING. MVFR SHOULD THEN PREVAIL FOR THE REMAINDER OF THE FCST
PERIOD. AS IS TYPICAL FOR LAKE EFFECT SNOW...EXPECT VIS AT ALL SITES
TO BE HIGHLY VARIABLE AT TIMES AS SNOW BANDS MOVE ACROSS THE AREA.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 441 PM EST WED JAN 30 2013
N TO NW GALES OF 35 TO 40 KNOTS WILL CONTINUE THROUGH MUCH OF
TONIGHT...WITH A FEW GALE FORCE GUSTS TO 35 KNOTS LINGERING E
THROUGH THURSDAY. LOW PRESSURE OVER LOWER MICHIGAN WILL LIFT
NORTHEAST INTO ONTARIO AND QUEBEC TONIGHT. WITH PLENTY OF
COLD AIR SINKING IN BEHIND THE LOW AND STRONG WINDS...HEAVY FREEZING
SPRAY WILL PREVAIL THROUGH THURSDAY NIGHT...AND MAY LINGER OVER THE
FAR EAST THROUGH FRIDAY NIGHT. A TROUGH WILL LINGER OVER LAKE
SUPERIOR THROUGH THURSDAY...AS STRONG HIGH PRESSURE SINKS ACROSS THE
PLAINS STATES. EXPECT THE HIGH PRESSURE SYSTEM TO WEAKEN SLIGHTLY
OVER THE MISSISSIPPI VALLEY FRIDAY...WHILE PUSHING A RIDGE ACROSS
WESTERN LAKE SUPERIOR. WEAK LOW PRESSURE WILL LINGER ACROSS EASTERN
LAKE SUPERIOR THROUGH SATURDAY. ANOTHER LOW PRESSURE TROUGH WILL
SINK SOUTHWARD FROM MANITOBA INTO THE UPPER GREAT LAKES SATURDAY
EVENING...BEFORE MOVING INTO THE LOWER GREAT LAKES DURING THE DAY
SUNDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST /6 AM CST/ FRIDAY FOR
MIZ001>003-009.
WINTER STORM WARNING UNTIL 6 AM EST THURSDAY FOR MIZ005.
WINTER STORM WARNING UNTIL 7 AM EST THURSDAY FOR MIZ006-007-085.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST SATURDAY FOR
LSZ265>267.
GALE WARNING UNTIL 4 AM EST THURSDAY FOR LSZ264>267.
HEAVY FREEZING SPRAY WARNING UNTIL 1 AM EST /MIDNIGHT CST/
SATURDAY FOR LSZ162-263-264.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...ROLFSON
SHORT TERM...JLB
LONG TERM...TITUS
AVIATION...ROLFSON
MARINE...JLB
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1152 PM EST WED JAN 30 2013
.AVIATION...
//DISCUSSION...
GUSTY WESTERLY WINDS WILL PERSIST THROUGH THE MORNING AS ARCTIC AIR
CONTINUES TO POUR INTO THE FORECAST AREA. STEEPENING LOW LEVEL LAPSE
RATES COURTESY OF THE COLD AIR ADVECTION WILL BRING SOME STRONG WIND
GUSTS DOWN TO THE SURFACE...LIKELY TOPPING 30 KNOTS AT TIMES THIS
MORNING. THE WINDS WILL DIMINISH SLIGHTLY THIS AFTERNOON AS THE
GRADIENT RELAXES. WIDESPREAD MVFR CIGS WILL SLOWLY LIFT DURING THE
COURSE OF THE TAF PERIOD AS THE COLD AIR ADVECTION LIFTS INVERSION
HEIGHTS. WHILE SNOW SHOWERS WILL REMAIN RATHER LIGHT
OVERNIGHT...SOME INCREASE IN INTENSITY IS EXPECTED AFTER
12Z...PRIMARILY FROM PTK SOUTH. WITH STILL SOME UNCERTAINTY AS TO
HOW THE LAKE BANDS WILL SET UP...WILL CONTINUE WITH MVFR TYPE
CIGS/VSBY IN THE SNOW SHOWERS THROUGH THE MORNING AT THIS TIME.
FOR DTW...EXPECT WESTERLY WIND GUSTS AROUND OR ABOVE 30 KNOTS
THROUGH THE MORNING AND INTO THE AFTERNOON. THERE IS A POTENTIAL FOR
ENHANCED SNOW SHOWERS OFF LAKE MICHIGAN TO IMPACT THE AIRPORT AFTER
12Z. GIVEN THE LOW CONFIDENCE AT THIS STAGE IN THE FORECAST...WILL
HOLD OFF ON INTRODUCING IFR TYPE CONDITIONS AT THIS TIME.
//DTW THRESHOLD THREATS...
* HIGH CONFIDENCE IN CEILING BELOW 5000 FT THROUGH THE TAF PERIOD.
* HIGH CONFIDENCE WESTERLY WIND GUSTS WILL EXCEED 28 KNOTS BETWEEN
06Z AND 19Z THURS.
&&
.PREV DISCUSSION...ISSUED 1007 PM EST WED JAN 30 2013
UPDATE...
THE WIDESPREAD RAIN WHICH HAS BEEN ROLLING ACROSS THE FORECAST
AREA THIS EVENING WILL QUICKLY LIFT OFF TO THE NORTHEAST OVER THE
NEXT COUPLE OF HOURS. RECENT OBSERVATIONS INDICATE THE BULK OF
THESE HEAVIER SHOWERS WILL BE OFF TO THE EAST PRIOR TO THE ARRIVAL
OF THE ARCTIC AIR AND CHANGE OVER TO SNOW. NONETHELESS...THE
ADVANCE OF DEEPER MOISTURE WITHIN THE MID LEVEL TROUGH AXIS WILL
ROTATE THROUGH THE FORECAST AREA OVERNIGHT PROVIDING SOME LIGHT
SNOW SHOWERS TO THE AREA. THE RESPONSE OFF LAKE MI FROM THE
AGGRESSIVE PUSH OF COLD AIR TONIGHT WILL ALSO BE QUITE GOOD. LAKE
ENHANCED SNOW SHOWERS SHOULD SUPPORT SOME HIGHER POPS ACROSS THE
SOUTHERN HALF OF THE FORECAST AREA OVERNIGHT. THE HIGHER INTENSITY
SNOW SHOWERS SHOULD HOLD OFF UNTIL AFTER DAYBREAK...SO SNOW ACCUMS
TONIGHT SHOULD BE MINOR. THE ARCTIC FRONT IS NOW ON THE DOORSTEP
OF THE FORECAST AREA AND WILL TRACK EAST OF THE AREA SHORTLY AFTER
MIDNIGHT. OVER THE NEXT TWO HOURS...TEMPS WILL RAPIDLY DROP BELOW
FREEZING. WHILE THE WINDS WILL HELP DRY THE ROAD SURFACES A
BIT...EXPECT THERE WILL SOME SLICK ROADS OVERNIGHT.
THE SURFACE LOW NOW OVER LAKE HURON WILL CONTINUE TO DEEPEN AS IT
PULLS NORTHEAST OF THE REGION OVERNIGHT. MEANWHILE...STRONG COLD
AIR ADVECTION WILL STEEPEN THE LOW LEVEL LAPSE RATES. THE MOST
RECENT RAP AND 18Z NAM CONTINUE TO SHOW A SOLID 40-45 KTS IN THE
MIXED LAYER OVERNIGHT /ESPECIALLY ACROSS THE EASTERN PORTIONS OF
THE FORECAST AREA/. THUS THE CURRENT WIND ADVISORY HEADLINE FOR
MUCH OF THE FORECAST AREA WILL REMAIN IN EFFECT.
PREV DISCUSSION...ISSUED 345 PM EST WED JAN 30 2013
SHORT TERM... TONIGHT
THERE ARE SEVERAL CONCERNS ASSOCIATED WITH THE FORECAST TONIGHT FOR
CONDITIONS THAT WILL HAVE AT LEAST MODERATE IMPACT AROUND SE
MICHIGAN. THE ADVISORY FOR HIGH WIND WILL BE MOST SIGNIFICANT
FOLLOWED CLOSELY BY THE COMBINATION OF FALLING TEMPERATURES AND RAIN
CHANGING TO SNOW ADDING A LAYER OF COMPLEXITY. ALL OF THIS WILL BE
DRIVEN BY A WAVE OF LOW PRESSURE THAT WILL MOVE FROM SOUTHWEST LOWER
MICHIGAN DURING THE AFTERNOON, THROUGH CENTRAL LAKE HURON AND INTO
EASTERN ONTARIO TONIGHT, ALL THE WHILE DEEPENING AS IT GOES.
THE DEEPENING TREND OF THE LOW AS IT PASSES TO OUR EAST WILL BE
FOSTERED BY THE DYNAMICS OF THE NEGATIVE TILT SHORT WAVE THAT IS
ALREADY TAKING SHAPE IN SATELLITE IMAGERY DURING THE AFTERNOON.
INCREASING SURFACE WIND TRAILING THE LOW IS ALSO OBSERVED TO PRODUCE
WIND GUSTS AROUND 30 KNOTS OVER THE MIDWEST AT PRESS TIME. WITH THE
SYSTEM ALREADY OFF TO A GOOD START, CONFIDENCE IS INCREASED IN THE
DEPICTIONS SHOWN IN THE ARRAY OF 12Z MODEL OUTPUT THAT BUILD A
STRONG WESTERLY WIND FIELD OVER SE MICHIGAN BY MIDNIGHT. SOME
GUSTINESS IS EXPECTED IN THE WARMER AIR AHEAD OF THE FRONT,
ASSOCIATED WITH THE LOW LEVEL JET, AND WITH THE ISALLOBARIC
COMPONENT OF FORCING IMMEDIATELY BEHIND THE FRONT, BUT THESE
ELEMENTS ARE NOT EXPECTED TO EXCEED ADVISORY CRITERIA. THAT IS
INSTEAD LIKELY TO OCCUR TOWARD MIDNIGHT THROUGH WEDNESDAY MORNING AS
DYNAMICALLY DRIVEN MID LEVEL SUBSIDENCE AND STRONG COLD ADVECTION
HELP DIRECT A 45-50 KNOT WIND FIELD TOWARD THE SURFACE FROM THE 850
TO 700 MB LAYER. MODEL CROSS SECTIONS INDICATE NEARLY 10 DEGREES(K)
OF THETA SURFACES INTERSECTING THE GROUND DURING THE INTERVAL OF
ISENTROPIC DECENT. MODEL SOUNDINGS THEN SHOW THE MIXED LAYER
DEEPENING TO NEAR THE 800 MB LEVEL FOR THE LATE OVERNIGHT HOURS WITH
45 KNOTS OF WIND AVAILABLE FOR CONTRIBUTION TO SURFACE WIND GUSTS.
AREAL COVERAGE WILL BE GREATEST ALONG AND SOUTH OF INTERSTATE 69
WITH THE THUMB VULNERABLE DUE TO WIND GUSTS MOVING OFF OF SAGINAW
BAY. PLAN TO LEAVE THE TRI CITIES OUT OF THE HEADLINE FOR NOW.
THE STRONG WINDS WILL PULL DRAMATICALLY COLDER AIR INTO SE MICHIGAN
DURING THE NIGHT WITH READINGS DROPPING INTO THE UPPER TEENS IN THE
TRI CITIES BY SUNRISE TO THE MID 20S METRO DETROIT. THE BULK OF
PRECIPITATION WILL COME IN THE FORM OF RAIN SHOWERS THROUGH MID
EVENING WITH THE CHANGE TO SNOW AT THE VERY TAIL END FOR JUST A
DUSTING OF ACCUMULATION IN THE DETROIT AREA AND UP TO AN INCH IN THE
NORTHERN THUMB.
LONG TERM...
LAKE MICHIGAN LAKE EFFECT MACHINE WILL BE CRANKING UP
THURSDAY...ENHANCED BY A GOOD UPPER LEVEL WAVE/MID LEVEL COLD POOL
SWINGING THROUGH THE MIDWEST/WESTERN OHIO VALLEY TOMORROW AFTERNOON.
STRONG WESTERLY WINDS (35-45 MPH) IN WAKE OF THE QUICKLY DEEPENING
LOW PRESSURE WILL USHER IN SUFFICIENTLY COLD AIRMASS...UPPER
NEGATIVE TEENS AT 850 MB OVER LOWER MICHIGAN...BUT LOWER NEGATIVE
20S SWINGING THROUGH THE WESTERN OHIO VALLEY. 700 MB COLD POOL OF
-28 TO -30 C OVER SOUTHERN LOWER MICHIGAN THURSDAY EVENING WITH
MODEST 925-850 MB LIFT/CONVERGENCE EXTENDING INTO SOUTHEAST
MICHIGAN...AND PLANNING ON CARRYING NUMEROUS POPS..ALTHOUGH FOCUS OF
ACTIVITY WILL LIKELY SHIFT FROM NORTH TO SOUTH THROUGH THE NIGHT AS
MODEST 850 THETA-E RIDGE SETTLES SOUTH. WITH A HIGH FLUFF FACTOR TO
SNOW...20+:1 RATIOS...A QUICK INCH OR TWO IS LIKELY IN SPOTS AS
925-850 MB PROFILES REMAIN IN THE DENDRITIC ZONE GROWTH REGION.
HEART OF THE COLD AIR/THERMAL TROUGH AXIS WILL BE IN PLACE FOR
FRIDAY...WITH 850 MB TEMPS HOVERING AROUND -20 C ON FRIDAY...AND
HAVE NO COMPLAINTS WITH INHERITED MAXES IN THE UPPER TEENS TO AROUND
20...IN LINE WITH LATEST GUIDANCE. A SURFACE RIDGE WILL ATTEMPT TO
MOVE IN FRIDAY NIGHT. IF THIS IS SUFFICIENT IN CLEARING OUT THE LOW
CLOUDS...LOOKING AT MINS AT OR BELOW ZERO FOR MUCH OF THE AREA WITH
EXPECTED FRESH SNOW COVER. CONFIDENCE IS NOT HIGH...AND WILL HAVE TO
PLAY IT CONSERVATIVE (LOW/MID SINGLE NUMBERS) AS THERE IS ALSO
LURKING WARM ADVECTION CLOUDS STREAMING INTO THE WESTERN GREAT
LAKES.
POLAR VORTEX LOOKS TO BE ANCHORED OVER/NEAR FAR NORTHERN HUDSON
BAY/SOUTHAMPTON ISLAND OVER THE NEXT SEVERAL DAYS...AND THIS WILL
MAINTAIN THE UPPER LEVEL NORTHWEST FLOW WITH A COUPLE
SHORTWAVES/CLIPPER SYSTEMS TO IMPACT OR TRACK NEAR SOUTHERN LOWER
MICHIGAN. WITH MOISTURE AT A PREMIUM...USUALLY NEED TO BE ON THE
NORTHEAST FLANK OF THE LOW (WARM ADVECTION/ISENTROPIC
ASCENT/MOISTURE CONVERGENCE) TO GET ANY SUBSTANTIAL
SNOWFALL. BEST GUESS AT TIMING OF SYSTEMS WOULD BE SATURDAY NIGHT
AND THEN AGAIN ON MONDAY. 12Z TRENDS OF EURO/GFS SUGGEST SATURDAY
NIGHTS SYSTEM WILL TRACK JUST A BIT TOO FAR SOUTH...WITH MONDAYS
SYSTEM/TRACK MORE FAVORABLE. THE EARLY NEXT WEEK LOW WILL ALSO HAVE
A BIT MORE OF A PACIFIC ORIGIN...AND THUS A BIT MORE MOISTURE. STILL
TOO EARLY TO GET A GOOD HANDLE OF THE GULF OF ALASKA ENERGY AND
EVENTUAL BREAKDOWN/SPILLING OVER INTO THE CONUS HOWEVER.
MARINE...
A POWERFUL COLD FRONT WILL SWEEP THROUGH LAKE HURON AND LOWER
MICHIGAN TONIGHT. INCREASING NORTHWEST WINDS AND A SURGE OF COLDER
AIR WILL BRING GALES TO ALL MARINE AREAS. CONSIDERABLE INSTABILITY
ACROSS THE LONG FETCH IN NORTHWEST FLOW OF THE OPEN WATERS WILL
MAINTAIN A LONGER PERIOD OF GALES FOR CENTRAL PORTIONS OF THE LAKE
THROUGH THURSDAY. THE COMBINATION OF THE STRONG WINDS, ARCTIC AIR,
AND COLDER WATER TEMPERATURE WILL LEAD TO HEAVY FREEZING SPRAY
ACROSS NORTHERN SECTIONS OF LAKE HURON DURING THIS TIME. HIGH
PRESSURE WILL SETTLE OVER THE OHIO VALLEY AND BRING IMPROVED
CONDITIONS BY FRIDAY.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...WIND ADVISORY...MIZ049-MIZ054-MIZ055-MIZ061-MIZ062-MIZ063-MIZ068-
MIZ069-MIZ070-MIZ075-MIZ076-MIZ082-MIZ083...UNTIL NOON
THURSDAY.
LAKE HURON...
GALE WARNING...LHZ361...UNTIL NOON THURSDAY.
HEAVY FREEZING SPRAY WARNING...LHZ361-LHZ362...UNTIL 7 PM THURSDAY.
GALE WARNING...LHZ362-LHZ363-LHZ462-LHZ463-LHZ464...UNTIL 7 PM
THURSDAY.
GALE WARNING...NEARSHORE WATERS FROM PORT AUSTIN TO PORT HURON
INCLUDING SAGINAW BAY...UNTIL 4 PM THURSDAY.
LAKE ST CLAIR...
GALE WARNING...UNTIL 4 PM THURSDAY.
MI WATERS OF LAKE ERIE...
GALE WARNING...UNTIL 4 PM THURSDAY.
&&
$$
AVIATION.....SC
UPDATE.......SC
SHORT TERM...BT
LONG TERM....SF
MARINE.......BT
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1013 PM EST WED JAN 30 2013
.UPDATE...
ISSUED AT 1012 PM EST WED JAN 30 2013
ALL HEADLINES THAT END THIS EVENING HAVE BEEN ALLOWED TO EXPIRE AS
SCHEDULED. ATTENTION NOW TURNS TO LAKE ENHANCED/LAKE EFFECT SNOW AS
COLDER AIR CONTINUES TO FLOW INTO THE AREA BEHIND DEPARTING STORM
SYSTEM. KMQT RADAR HAS SHOWN A NICE EXPANSION OF HVY SNOW BANDS OFF
LAKE SUPERIOR THIS EVENING UNDER LINGERING DEEP MOISTURE/CAA...AND
VAD WIND PROFILE SHOWS NEARLY UNIDIRECTIONAL NORTHERLY WINDS TO
11KFT MSL. THERE ARE CONFLICTING SIGNALS ON HOW MUCH THE WIND MAY
BACK OVERNIGHT AS LOCAL HIGH RES-WRF MAINTAINS A MORE NRLY WIND INTO
NCNTRL UPPER MI WHILE NAM BACKS WIND MORE NW. GIVEN TRENDS IN HRLY
RUC RAPID REFRESH RUNS TO SLOW THE BACKING...OPTED TO EXTEND WARNING
FOR MARQUETTE COUNTY UNTIL 11Z. WITH RATHER PERSISTENT HVY SNOW
OCCURRING AT THE OFFICE THIS EVENING AND RADAR IMAGERY SHOWING
EXPANSION OF HVY SNOW BANDS...WOULD NOT BE SURPRISED TO SEE SOME
LOCALIZED ACCUMULATIONS OVER 1 FOOT DURING THE NIGHT IN THE HIGHER
TERRAIN BETWEEN BIG BAY...NEGAUNEE...GWINN AND SKANDIA. THIS HVY
SNOW WILL ALSO TARGET WRN ALGER COUNTY WEST OF SHINGLETON. WHILE
WARNING FOR ALGER/LUCE/NRN SCHOOLCRAFT ONLY GOES TO 12Z...WILL LET
MID SHIFT TAKE A LOOK AT REPLACEMENT WITH A LONGER DURATION LAKE
EFFECT SNOW ADVY OR WARNING FOR THAT AREA.
TO THE W...NO CHANGES WERE MADE TO THE GOGEBIC/ONTONAGON ADVY. OVER
THE KEWEENAW...COLD AIR WILL PUSH THE DGZ DOWN TO NEAR THE SFC...
RESULTING IN SMALL SNOWFLAKES THAT ARE VERY EFFECTIVE AT REDUCING
VIS. WHILE ACCUMULATIONS WILL PROBABLY ONLY BE IN THE 2-4 INCH
RANGE/12HRS AT MOST LOCATIONS...VERY LOW VIS DURING -SHSN ALONG WITH
OCNL BLSN SUGGEST AN ADVY HEADLINE IS WARRANTED FOR KEWEENAW/NRN
HOUGHTON AS DRIVING WILL BE DIFFICULT AT TIMES.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 441 PM EST WED JAN 30 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH FROM
HUDSON BAY AND NW ONTARIO THROUGH MN/IA INTO ERN OK. THE POTENT
SHORTWAVE TROUGH OVER SW WI AND ASSOCIATED DEFORMATION ZONE
CONTINUED TO SUPPORT A HEAVY SNOW BAND FROM ERN WI INTO THE E HALF
OF UPPER MI. LIGHTER SNOW WAS OBSERVED OVER THE WEST HALF OF UPPER
MI. SNOW TOTALS OF AROUND 6 INCHES WERE OBSERVED BY 21Z FROM THE NWS
MQT OFFICE TO MNM...GLADSTONE AND MANISTIQUE. A TIGHT GRADIENT BTWN
THE 987 MB LOW OVER SRN LOWER MI AND ARCTIC HIGH PRES BUILDING INTO
THE PLAINS HAS RESULTED IN GALES ACROSS LAKE SUPERIOR AND GUSTY N
WINDS TO 30 MPH OVER MOST OF THE CWA.
TONIGHT AND THURSDAY...THE HEAVY SNOW BAND WHICH CORRELATED WELL WITH
NAM/RUC 700-600 MB FGEN IS EXPECTED TO SHIF QUICKLY TO THE NORTHEAST
THIS EVENING LEAVING MAINLY LIGHT SNOW THAT WILL DIMINISH BTWN
00Z-03Z. HOWEVER...COLDER AIR MOVING IN ON THE STRONG N WINDS
COMBINED WITH 850 MB TEMPS TO AROUND -15C WILL CONTINUE TO SUPPORT
LCLY HIGHER SNOWFALL RATES N CNTRL...ESPECIALLY VCTY MARQUETTE THIS
EVENING WITH CYCLONIC LOW LEVEL 340-350 WIND DIRECTION NEAR THE
SHORE. FAVORABLE UPSLOPE NRLY FLOW INTO THE FAR WEST SHOULD ALSO
BRING INCREASING LES INTO IWD. RADAR TRENDS AND MODELS SUGGEST
ADDITIONAL SYNOPTIC SNOW POTENTIAL IN THE 1 TO 3 INCH RANGE BTWN 21Z-
03Z. HOWEVER AREAS WITH LAKE CONTRIBUTION COULD SEE ANOTHER 3 TO 6
INCHES THROUGH 12Z/THU.
AS THE STRONGER SYNOPTIC FORCING WITH THE SHRTWV MOVES OUT THIS
EVENING...HEADLINES ARE SET TO EXPIRE BY AROUND 03Z OVER THE S CWA.
A TRANSISTION TO LAKE EFFECT SNOW WILL CONTINUE OVERNIGHT WITH
FAVORABLE CONDITION PERSISTING INTO THURSDAY. ANOTHER TRAILING
SHRTWV SLIDING SE INTO THE UPPER LAKES WILL MAINTAIN 850-700 MB
MOISTURE AND INVERSION HEIGHTS AOA 10K FT. WITH THE WINDS BACKING
SLIGHTLY TO 340-330 THE HEAVIER LES WILL CONTINUE TO FOCUS INTO THE
FAR WEST AND TO AREAS EAST OF MARQUETTE. 850 MB TEMPS FALLING TO
AROUND -20C MAY SHRINK THE DGZ LAYER INTO THE 1K-3K RANGE BUT STILL
SHOULD BE SUFFICIENT FOR LSR VALUES CLOSE TO 25/1. ADDITIONAL
SNOWFALL AMOUNTS OF 3 TO 7 INCHES ARE POSSIBLE.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 441 PM EST WED JAN 30 2013
MODELS ARE IN GOOD GENERAL AGREEMENT THROUGH THE EXTENDED WITH DEEP
UPPER TROUGH STARTING THE PERIOD FRI AND GRADUALLY BREAKING DOWN AND
SHIFTING WEST THROUGH NEXT WED...AS AN UPPER RIDGE MOVES INTO THE
WRN CONUS.
GOOD NW WIND LES WILL BE ONGOING INTO THU NIGHT GIVEN NW LOW LEVEL
FLOW...AMPLE MOISTURE AND 825MB INVERSION TOP TEMPS AROUND -25C.
LATE THU NIGHT AND FRI...A SFC HIGH WILL MOVE S OF THE CWA WHILE A
SHORTWAVE TROUGH DIVES IN FROM THE NW FORMING A MESO-LOW OVER ERN
LAKE SUPERIOR LATE FRI. THIS TURNS THE NW WINDS WLY BY FRI
AFTERNOON...FOCUSING LES OVER THE KEWEENAW AND FAR NE UPPER MI.
PRIOR WIND SHIFT...THE BEST LES WILL BE FOCUSED OVER ONTONAGON AND
GOGEBIC COUNTIES AND OVER ERN UPPER MI FROM MUNISING TO GRAND
MARAIS. LES SHOULD INITIALLY WEAKEN SOME LATE THU NIGHT AS RIDGING
MOVES INTO THE AREA...BUT WILL GET A BOOST FROM THE SHORTWAVE LATER
ON FRIDAY. THERE IS ALREADY A LES ADVISORY FOR ONTONAGON/GOGEBIC
COUNTIES THROUGH THU NIGHT...AND THAT STILL LOOKS FINE. BUT WILL
LIKELY ALSO NEED HEADLINES FOR THE ERN U.P. THU NIGHT INTO FRI. THE
KEWEENAW MAY ALSO NEED HEADLINES FRI INTO FRI NIGHT. WILL NOT ISSUE
ANY NEW HEADLINES AT THIS POINT GIVEN HEADLINES ALREADY IN EFFECT
OVER THE ERN U.P. AND SOME UNCERTAINTY AS TO THE RESIDENCE TIME AND
INTENSITY OF ANY STRONGER BANDS THAT MOVE ACROSS THE KEWEENAW.
THU NIGHT THROUGH FRI NIGHT LOOKS TO BE THE COLDEST PERIOD OF THE
NEXT WEEK. LOWS THU NIGHT AND FRI NIGHT LOOKS TO FALL TO THE TEENS
BELOW ZERO WITH WIND CHILLS TO -35F OVER PARTS OF THE INTERIOR.
HIGHS ON FRI LOOK TO BE AROUND ZERO OVER THE INTERIOR W...AND IN THE
LOW TEENS ABOVE ZERO E. WIND CHILL VALUES ARE CURRENTLY FORECAST TO
BE IN TEENS BELOW ZERO AT THE WARMEST FRI AFTERNOON OVER THE
INTERIOR W...AND IN THE SINGLE DIGITS BELOW ZERO E. WILL LIKELY NEED
SOME WIND CHILL ADVISORY HEADLINES UP WHERE THERE ARE NO OTHER
WINTER WX HEADLINES.
MODELS IN RELATIVELY GOOD AGREEMENT WITH A CLIPPER SHORTWAVE MOVING
THROUGH LATE SAT INTO EARLY SAT NIGHT...BUT ONLY MINOR SYNOPTIC SNOW
ACCUMULATIONS AND INCREASED NW WIND LES ARE EXPECTED TO RESULT FROM
THE SYSTEM.
SFC RIDGING MOVES OVER ON SUN AHEAD OF THE NEXT...STRONGER...CLIPPER
SYSTEM THAT MODEL DEPICT MOVING THROUGH. ALTHOUGH MODELS SEEM TO
AGREE FAIRLY WELL ON THE OVERALL TRACK AND INTENSITY OF THE
SYSTEM...THE 00Z/30 ECMWF IS 6-12 HOURS FASTER THAN THE 12Z/30 GFS.
SEVERAL INCHES OF SNOW MAY RESULT AREA WIDE FROM THIS SYSTEM.
MODELS THEN INDICATE...WITH GREATER UNCERTAINTY...ANOTHER CLIPPER
SYSTEM MOVING THROUGH SOMETIME MIDWEEK.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 655 PM EST WED JAN 30 2013
AT KIWD...LAKE EFFECT -SHSN WILL INCREASE TONIGHT AS COLDER AIR
FLOWS INTO THE AREA AND LOW-LEVEL WINDS BECOME MORE CYCLONIC. AS A
RESULT...MVFR CONDITIONS THIS EVENING SHOULD FALL TO IFR OVERNIGHT
THRU MUCH OF THE DAY THU. AT KCMX...LIFR CONDITIONS HAVE ALREADY
DEVELOPED AND WILL LIKELY CONTINUE THRU THE FCST PERIOD AS LAKE
EFFECT -SHSN CONTINUE UNDER INCREASINGLY COLDER AIR MASS. WITH THE
COLDER AIR...SNOWFLAKE SIZE WILL BE SMALL AND VERY EFFECTIVE AT
KEEPING VIS LOW. AT KSAW...SYNOPTIC SNOW SHIELD WILL BE EXITING
LEAVING LAKE EFFECT -SHSN LATE EVENING THRU THU. AS A RESULT...
EXPECT INITIAL LIFR CONDITIONS TO IMPROVE TO IFR THIS EVENING AND TO
MOSTLY MVFR OVERNIGHT THRU THU. AS IS TYPICAL FOR LAKE EFFECT
SNOW...EXPECT VIS AT ALL SITES TO BE HIGHLY VARIABLE AT TIMES AS
SNOW BANDS MOVE ACROSS THE AREA.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 441 PM EST WED JAN 30 2013
N TO NW GALES OF 35 TO 40 KNOTS WILL CONTINUE THROUGH MUCH OF
TONIGHT...WITH A FEW GALE FORCE GUSTS TO 35 KNOTS LINGERING E
THROUGH THURSDAY. LOW PRESSURE OVER LOWER MICHIGAN WILL LIFT
NORTHEAST INTO ONTARIO AND QUEBEC TONIGHT. WITH PLENTY OF
COLD AIR SINKING IN BEHIND THE LOW AND STRONG WINDS...HEAVY FREEZING
SPRAY WILL PREVAIL THROUGH THURSDAY NIGHT...AND MAY LINGER OVER THE
FAR EAST THROUGH FRIDAY NIGHT. A TROUGH WILL LINGER OVER LAKE
SUPERIOR THROUGH THURSDAY...AS STRONG HIGH PRESSURE SINKS ACROSS THE
PLAINS STATES. EXPECT THE HIGH PRESSURE SYSTEM TO WEAKEN SLIGHTLY
OVER THE MISSISSIPPI VALLEY FRIDAY...WHILE PUSHING A RIDGE ACROSS
WESTERN LAKE SUPERIOR. WEAK LOW PRESSURE WILL LINGER ACROSS EASTERN
LAKE SUPERIOR THROUGH SATURDAY. ANOTHER LOW PRESSURE TROUGH WILL
SINK SOUTHWARD FROM MANITOBA INTO THE UPPER GREAT LAKES SATURDAY
EVENING...BEFORE MOVING INTO THE LOWER GREAT LAKES DURING THE DAY
SUNDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST /6 AM CST/ FRIDAY FOR
MIZ001>003-009.
WINTER STORM WARNING UNTIL 6 AM EST THURSDAY FOR MIZ005.
WINTER STORM WARNING UNTIL 7 AM EST THURSDAY FOR MIZ006-007-085.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST SATURDAY FOR
LSZ265>267.
GALE WARNING UNTIL 4 AM EST THURSDAY FOR LSZ264>267.
HEAVY FREEZING SPRAY WARNING UNTIL 1 AM EST /MIDNIGHT CST/
SATURDAY FOR LSZ162-263-264.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...ROLFSON
SHORT TERM...JLB
LONG TERM...TITUS
AVIATION...ROLFSON
MARINE...JLB
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1007 PM EST WED JAN 30 2013
.UPDATE...
THE WIDESPREAD RAIN WHICH HAS BEEN ROLLING ACROSS THE FORECAST
AREA THIS EVENING WILL QUICKLY LIFT OFF TO THE NORTHEAST OVER THE
NEXT COUPLE OF HOURS. RECENT OBSERVATIONS INDICATE THE BULK OF
THESE HEAVIER SHOWERS WILL BE OFF TO THE EAST PRIOR TO THE ARRIVAL
OF THE ARCTIC AIR AND CHANGE OVER TO SNOW. NONETHELESS...THE
ADVANCE OF DEEPER MOISTURE WITHIN THE MID LEVEL TROUGH AXIS WILL
ROTATE THROUGH THE FORECAST AREA OVERNIGHT PROVIDING SOME LIGHT
SNOW SHOWERS TO THE AREA. THE RESPONSE OFF LAKE MI FROM THE
AGGRESSIVE PUSH OF COLD AIR TONIGHT WILL ALSO BE QUITE GOOD. LAKE
ENHANCED SNOW SHOWERS SHOULD SUPPORT SOME HIGHER POPS ACROSS THE
SOUTHERN HALF OF THE FORECAST AREA OVERNIGHT. THE HIGHER INTENSITY
SNOW SHOWERS SHOULD HOLD OFF UNTIL AFTER DAYBREAK...SO SNOW ACCUMS
TONIGHT SHOULD BE MINOR. THE ARCTIC FRONT IS NOW ON THE DOORSTEP
OF THE FORECAST AREA AND WILL TRACK EAST OF THE AREA SHORTLY AFTER
MIDNIGHT. OVER THE NEXT TWO HOURS...TEMPS WILL RAPIDLY DROP BELOW
FREEZING. WHILE THE WINDS WILL HELP DRY THE ROAD SURFACES A
BIT...EXPECT THERE WILL SOME SLICK ROADS OVERNIGHT.
THE SURFACE LOW NOW OVER LAKE HURON WILL CONTINUE TO DEEPEN AS IT
PULLS NORTHEAST OF THE REGION OVERNIGHT. MEANWHILE...STRONG COLD
AIR ADVECTION WILL STEEPEN THE LOW LEVEL LAPSE RATES. THE MOST
RECENT RAP AND 18Z NAM CONTINUE TO SHOW A SOLID 40-45 KTS IN THE
MIXED LAYER OVERNIGHT /ESPECIALLY ACROSS THE EASTERN PORTIONS OF
THE FORECAST AREA/. THUS THE CURRENT WIND ADVISORY HEADLINE FOR
MUCH OF THE FORECAST AREA WILL REMAIN IN EFFECT.
&&
.AVIATION...ISSUED 628 PM EST WED JAN 30 2013
//DISCUSSION...
DEEPENING LOW PRESSURE NOW TRACKING INTO LAKE HURON WILL SEND TWO
FRONTS ACROSS SE MI THIS EVENING. THE FIRST FRONT WILL BE TRAVERSING
THE TERMINALS AT THE START OF THE TAF PERIOD AND WILL LEAD TO A
SLIGHT VEERING OF THE WINDS TO THE SOUTHWEST WITH AN INCREASE IN
WIND SPEEDS. THE SECONDARY FRONT...WHICH IS THE TRUE ARCTIC FRONT
WILL THEN PUSH THROUGH SE MI AROUND 03Z. THIS FRONT WILL BE MARKED
BY A DRAMATIC INCREASE IN WESTERLY WIND SPEEDS...PERSISTING
THROUGH THE NIGHT AND INTO THURS MORNING...WITH GUSTS EXPECTED TO
TOP 30 KNOTS. WHILE CEILINGS HAVE IMPROVED MARKEDLY THE LAST
COUPLE OF HOURS. THE LOWER CEILINGS ACROSS WRN LOWER MI WILL
ADVANCE BACK INTO SE MI THIS EVENING WITH THE APPROACH OF THE
ARCTIC FRONT. CEILINGS WILL THEN STEADILY IMPROVE DURING THE NIGHT
AS THE COLD AIR DEEPENS AND LIFTS INVERSION HEIGHTS. PRECIP PRIOR
TO THE ARCTIC FRONT WILL BE ALL RAIN. MINOR SNOW ACCUMS ARE
POSSIBLE AS THE RAIN RAPIDLY CHANGES OVER TO SNOW LATE THIS
EVENING.
FOR DTW...UPSTREAM OBS SUPPORT WIND GUSTS REACHING 25-30 KNOTS
BETWEEN 00Z AND 03Z. THE ARCTIC FRONTAL PASSAGE AROUND 03Z WILL VEER
THE WINDS TO THE WEST WHILE GUSTS ARE EXPECTED TO REACH 35 KNOTS OR
HIGHER. THE STRONG WESTERLY WINDS WILL PERSIST THROUGH THURS
MORNING.
//DTW THRESHOLD THREATS...
* HIGH CONFIDENCE IN CEILING BELOW 5000 FT TONIGHT AND THURSDAY.
* HIGH CONFIDENCE WESTERLY WIND GUSTS WILL EXCEED 30 KNOTS BETWEEN
03Z AND 19Z THURS.
* HIGH CONFIDENCE PRECIP TYPE AS RAIN THROUGH 03Z...THEN QUICKLY
CHANGING OVER TO SNOW BY 04Z.
&&
.PREV DISCUSSION...ISSUED 345 PM EST WED JAN 30 2013
SHORT TERM... TONIGHT
THERE ARE SEVERAL CONCERNS ASSOCIATED WITH THE FORECAST TONIGHT FOR
CONDITIONS THAT WILL HAVE AT LEAST MODERATE IMPACT AROUND SE
MICHIGAN. THE ADVISORY FOR HIGH WIND WILL BE MOST SIGNIFICANT
FOLLOWED CLOSELY BY THE COMBINATION OF FALLING TEMPERATURES AND RAIN
CHANGING TO SNOW ADDING A LAYER OF COMPLEXITY. ALL OF THIS WILL BE
DRIVEN BY A WAVE OF LOW PRESSURE THAT WILL MOVE FROM SOUTHWEST LOWER
MICHIGAN DURING THE AFTERNOON, THROUGH CENTRAL LAKE HURON AND INTO
EASTERN ONTARIO TONIGHT, ALL THE WHILE DEEPENING AS IT GOES.
THE DEEPENING TREND OF THE LOW AS IT PASSES TO OUR EAST WILL BE
FOSTERED BY THE DYNAMICS OF THE NEGATIVE TILT SHORT WAVE THAT IS
ALREADY TAKING SHAPE IN SATELLITE IMAGERY DURING THE AFTERNOON.
INCREASING SURFACE WIND TRAILING THE LOW IS ALSO OBSERVED TO PRODUCE
WIND GUSTS AROUND 30 KNOTS OVER THE MIDWEST AT PRESS TIME. WITH THE
SYSTEM ALREADY OFF TO A GOOD START, CONFIDENCE IS INCREASED IN THE
DEPICTIONS SHOWN IN THE ARRAY OF 12Z MODEL OUTPUT THAT BUILD A
STRONG WESTERLY WIND FIELD OVER SE MICHIGAN BY MIDNIGHT. SOME
GUSTINESS IS EXPECTED IN THE WARMER AIR AHEAD OF THE FRONT,
ASSOCIATED WITH THE LOW LEVEL JET, AND WITH THE ISALLOBARIC
COMPONENT OF FORCING IMMEDIATELY BEHIND THE FRONT, BUT THESE
ELEMENTS ARE NOT EXPECTED TO EXCEED ADVISORY CRITERIA. THAT IS
INSTEAD LIKELY TO OCCUR TOWARD MIDNIGHT THROUGH WEDNESDAY MORNING AS
DYNAMICALLY DRIVEN MID LEVEL SUBSIDENCE AND STRONG COLD ADVECTION
HELP DIRECT A 45-50 KNOT WIND FIELD TOWARD THE SURFACE FROM THE 850
TO 700 MB LAYER. MODEL CROSS SECTIONS INDICATE NEARLY 10 DEGREES(K)
OF THETA SURFACES INTERSECTING THE GROUND DURING THE INTERVAL OF
ISENTROPIC DECENT. MODEL SOUNDINGS THEN SHOW THE MIXED LAYER
DEEPENING TO NEAR THE 800 MB LEVEL FOR THE LATE OVERNIGHT HOURS WITH
45 KNOTS OF WIND AVAILABLE FOR CONTRIBUTION TO SURFACE WIND GUSTS.
AREAL COVERAGE WILL BE GREATEST ALONG AND SOUTH OF INTERSTATE 69
WITH THE THUMB VULNERABLE DUE TO WIND GUSTS MOVING OFF OF SAGINAW
BAY. PLAN TO LEAVE THE TRI CITIES OUT OF THE HEADLINE FOR NOW.
THE STRONG WINDS WILL PULL DRAMATICALLY COLDER AIR INTO SE MICHIGAN
DURING THE NIGHT WITH READINGS DROPPING INTO THE UPPER TEENS IN THE
TRI CITIES BY SUNRISE TO THE MID 20S METRO DETROIT. THE BULK OF
PRECIPITATION WILL COME IN THE FORM OF RAIN SHOWERS THROUGH MID
EVENING WITH THE CHANGE TO SNOW AT THE VERY TAIL END FOR JUST A
DUSTING OF ACCUMULATION IN THE DETROIT AREA AND UP TO AN INCH IN THE
NORTHERN THUMB.
LONG TERM...
LAKE MICHIGAN LAKE EFFECT MACHINE WILL BE CRANKING UP
THURSDAY...ENHANCED BY A GOOD UPPER LEVEL WAVE/MID LEVEL COLD POOL
SWINGING THROUGH THE MIDWEST/WESTERN OHIO VALLEY TOMORROW AFTERNOON.
STRONG WESTERLY WINDS (35-45 MPH) IN WAKE OF THE QUICKLY DEEPENING
LOW PRESSURE WILL USHER IN SUFFICIENTLY COLD AIRMASS...UPPER
NEGATIVE TEENS AT 850 MB OVER LOWER MICHIGAN...BUT LOWER NEGATIVE
20S SWINGING THROUGH THE WESTERN OHIO VALLEY. 700 MB COLD POOL OF
-28 TO -30 C OVER SOUTHERN LOWER MICHIGAN THURSDAY EVENING WITH
MODEST 925-850 MB LIFT/CONVERGENCE EXTENDING INTO SOUTHEAST
MICHIGAN...AND PLANNING ON CARRYING NUMEROUS POPS..ALTHOUGH FOCUS OF
ACTIVITY WILL LIKELY SHIFT FROM NORTH TO SOUTH THROUGH THE NIGHT AS
MODEST 850 THETA-E RIDGE SETTLES SOUTH. WITH A HIGH FLUFF FACTOR TO
SNOW...20+:1 RATIOS...A QUICK INCH OR TWO IS LIKELY IN SPOTS AS
925-850 MB PROFILES REMAIN IN THE DENDRITIC ZONE GROWTH REGION.
HEART OF THE COLD AIR/THERMAL TROUGH AXIS WILL BE IN PLACE FOR
FRIDAY...WITH 850 MB TEMPS HOVERING AROUND -20 C ON FRIDAY...AND
HAVE NO COMPLAINTS WITH INHERITED MAXES IN THE UPPER TEENS TO AROUND
20...IN LINE WITH LATEST GUIDANCE. A SURFACE RIDGE WILL ATTEMPT TO
MOVE IN FRIDAY NIGHT. IF THIS IS SUFFICIENT IN CLEARING OUT THE LOW
CLOUDS...LOOKING AT MINS AT OR BELOW ZERO FOR MUCH OF THE AREA WITH
EXPECTED FRESH SNOW COVER. CONFIDENCE IS NOT HIGH...AND WILL HAVE TO
PLAY IT CONSERVATIVE (LOW/MID SINGLE NUMBERS) AS THERE IS ALSO
LURKING WARM ADVECTION CLOUDS STREAMING INTO THE WESTERN GREAT
LAKES.
POLAR VORTEX LOOKS TO BE ANCHORED OVER/NEAR FAR NORTHERN HUDSON
BAY/SOUTHAMPTON ISLAND OVER THE NEXT SEVERAL DAYS...AND THIS WILL
MAINTAIN THE UPPER LEVEL NORTHWEST FLOW WITH A COUPLE
SHORTWAVES/CLIPPER SYSTEMS TO IMPACT OR TRACK NEAR SOUTHERN LOWER
MICHIGAN. WITH MOISTURE AT A PREMIUM...USUALLY NEED TO BE ON THE
NORTHEAST FLANK OF THE LOW (WARM ADVECTION/ISENTROPIC
ASCENT/MOISTURE CONVERGENCE) TO GET ANY SUBSTANTIAL
SNOWFALL. BEST GUESS AT TIMING OF SYSTEMS WOULD BE SATURDAY NIGHT
AND THEN AGAIN ON MONDAY. 12Z TRENDS OF EURO/GFS SUGGEST SATURDAY
NIGHTS SYSTEM WILL TRACK JUST A BIT TOO FAR SOUTH...WITH MONDAYS
SYSTEM/TRACK MORE FAVORABLE. THE EARLY NEXT WEEK LOW WILL ALSO HAVE
A BIT MORE OF A PACIFIC ORIGIN...AND THUS A BIT MORE MOISTURE. STILL
TOO EARLY TO GET A GOOD HANDLE OF THE GULF OF ALASKA ENERGY AND
EVENTUAL BREAKDOWN/SPILLING OVER INTO THE CONUS HOWEVER.
MARINE...
A POWERFUL COLD FRONT WILL SWEEP THROUGH LAKE HURON AND LOWER
MICHIGAN TONIGHT. INCREASING NORTHWEST WINDS AND A SURGE OF COLDER
AIR WILL BRING GALES TO ALL MARINE AREAS. CONSIDERABLE INSTABILITY
ACROSS THE LONG FETCH IN NORTHWEST FLOW OF THE OPEN WATERS WILL
MAINTAIN A LONGER PERIOD OF GALES FOR CENTRAL PORTIONS OF THE LAKE
THROUGH THURSDAY. THE COMBINATION OF THE STRONG WINDS, ARCTIC AIR,
AND COLDER WATER TEMPERATURE WILL LEAD TO HEAVY FREEZING SPRAY
ACROSS NORTHERN SECTIONS OF LAKE HURON DURING THIS TIME. HIGH
PRESSURE WILL SETTLE OVER THE OHIO VALLEY AND BRING IMPROVED
CONDITIONS BY FRIDAY.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...WIND ADVISORY...MIZ049-MIZ054-MIZ055-MIZ061-MIZ062-MIZ063-MIZ068-
MIZ069-MIZ070-MIZ075-MIZ076-MIZ082-MIZ083...UNTIL NOON
THURSDAY.
LAKE HURON...
GALE WARNING...LHZ361...UNTIL NOON THURSDAY.
HEAVY FREEZING SPRAY WARNING...LHZ361-LHZ362...UNTIL 7 PM THURSDAY.
GALE WARNING...LHZ362-LHZ363-LHZ462-LHZ463-LHZ464...UNTIL 7 PM
THURSDAY.
GALE WARNING...NEARSHORE WATERS FROM PORT AUSTIN TO PORT HURON
INCLUDING SAGINAW BAY...UNTIL 4 PM THURSDAY.
LAKE ST CLAIR...
GALE WARNING...UNTIL 4 PM THURSDAY.
MI WATERS OF LAKE ERIE...
GALE WARNING...UNTIL 4 PM THURSDAY.
&&
$$
UPDATE.......SC
AVIATION.....SC
SHORT TERM...BT
LONG TERM....SF
MARINE.......BT
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1126 PM CST WED JAN 30 2013
.AVIATION...06Z KGRI TAF...AN APPROACHING UPPER LEVEL DISTURBANCE
WILL SPREAD MVFR CIGS ACROSS THE TERMINAL BY THE EARLY MORNING
HOURS THURSDAY...WITH A FEW SNOW FLAKES NOT OUT OF THE QUESTION.
ALREADY SEEING MVFR CIGS TO THE NORTHWEST AT KVTN WITH SOME
-SN...AND EXPECT THIS CLOUD COVER TO REACH KGRI AROUND
31/12Z...AND PERSIST THROUGH AROUND 31/18Z. WINDS WILL THE PRIMARY
FOCUS THROUGH THE DAY THURSDAY AS AN AREA OF SURFACE HIGH PRESSURE
OVER THE DAKOTAS SLIDES SOUTHWARD...RESULTING IN A TIGHTENING
PRESSURE GRADIENT. EXPECT WINDS TO GUST AS HIGH AS 30KTS DURING
THE AFTERNOON HOURS...BEFORE RAPIDLY DIMINISHING AROUND
01/00Z...AS THE CENTER OF THIS HIGH PRESSURE SYSTEM REACHES
EASTERN NEBRASKA.
&&
.PREV DISCUSSION... /ISSUED 956 PM CST WED JAN 30 2013/
UPDATE...EVENING UPPER AIR ANALYSIS PER RAP ANALYSIS DATA
SUGGESTS A LARGE MID AND UPPER LEVEL LONGWAVE TROUGH PERSISTS OVER
THE CENTRAL CONUS. MID AND UPPER LEVEL JET ENERGY EXTENDS
SOUTH/SOUTHEAST ACROSS THE WESTERN CONUS...THEN EAST ACROSS THE
SOUTHERN PLAINS...AND EVENTUALLY NORTHEAST ACROSS THE EASTERN ONE-
THIRD OF THE CONUS. ALTHOUGH MID AND UPPER TROPOSPHERIC FLOW HAS
BEEN FAIRLY WEAK OVER OUR AREA THROUGH THIS EVENING...THE MID
LEVEL WIND FIELD IS INTENSIFYING WITH THE APPROACH OF A ~80KT MID
LEVEL JET STREAK FROM THE NORTHWEST. WATER VAPOR IMAGERY INDICATES
FAIRLY MEAGER MID LEVEL MOISTURE OVER OUR AREA...ALTHOUGH SOME
MODEST INCREASE IN MID LEVEL MOISTURE IS NOTED ADVECTING INTO THE
AREA FROM THE NORTHWEST VIA THE MID LEVEL JET AXIS. A MID LEVEL
SHORT WAVE IS ALSO NOTED OVER PORTIONS OF SOUTHERN MANITOBA AND
SOUTHERN ONTARIO...MOVING SOUTH/SOUTHEAST WITHIN THE MEAN FLOW. AT
THE SURFACE LOW BAROMETRIC PRESSURE IS NOTED OVER PORTIONS OF
CENTRAL NEBRASKA...WITH RAPIDLY INCREASING BAROMETRIC PRESSURE
NOTED UPSTREAM ACROSS THE DAKOTAS AND PORTIONS OF MONTANA. THE LOW
LEVEL WIND FIELD OVER OUR AREA REMAINS FAIRLY LIGHT BUT STILL FROM
THE NORTHWEST FOR THE MOST PART.
GUIDANCE FROM THE NAM...OPERATIONAL GFS...EC...AND SREF-MEAN ALL
SUGGEST THE MID LEVEL SHORT WAVE...CURRENTLY ADVANCING
SOUTH/SOUTHEAST FROM SOUTHERN CANADA...WILL CONTINUE MOVING
SOUTHEAST ACROSS PORTIONS OF THE NORTHERN PLAINS AND UPPER
MISSISSIPPI VALLEY THROUGH THE NEXT 18-24 HOURS. IT APPEARS AS
THOUGH THE PRIMARY AXIS OF OMEGA AHEAD OF THE MID LEVEL TROUGH
AXIS WILL REMAIN NORTHEAST OF OUR AREA...ALTHOUGH THE SOUTHWESTERN
PERIPHERY OF THE MID LEVEL TROUGH AXIS COULD EXTEND JUST FAR
ENOUGH SOUTHWEST TO CLIP NORTHEASTERN PORTIONS OF OUR CWA AND
GENERATE SOME VERY LIGHT PRECIPITATION TONIGHT. FORECAST PROXIMITY
SOUNDINGS FROM ACROSS OUR CWA...PER THE NAM AND OPERATIONAL
GFS...SUGGEST LOW TO MID TROPOSPHERIC MOISTURE WILL LIKELY REMAIN
TOO MEAGER FOR SIGNIFICANT PRECIPITATION PRODUCTION...BUT STILL
CANNOT RULE OUT A FEW SNOW FLURRIES ACROSS OUR NORTHEAST.
OVERALL THE GOING FORECAST IS IN GREAT SHAPE...BUT DID GO AHEAD
AND TRIM THE MENTION OF FLURRIES ACROSS OUR CWA...AND THIS MENTION
IS NOW RELEGATED TO OUR FAR NORTHEASTERN CWA. FORECAST OVERNIGHT
LOWS ALSO LOOK GOOD FOR THE TIME BEING...GENERALLY IN THE TEENS
WITH THURSDAY MORNING APPARENT TEMPERATURE VALUES APPROACHING -10
ACROSS OUR NORTHEAST AROUND SUNRISE. ALL OTHER CHANGES WERE TO
HOURLY TEMPERATURE...WIND...SKY...AND DEWPOINT GRIDS TO BETTER
REFLECT CURRENT CONDITIONS.
PREV DISCUSSION... /ISSUED 423 PM CST WED JAN 30 2013/
SHORT TERM...TONIGHT AND THURSDAY. WE WILL BE WITHIN NORTHWEST
FLOW...BETWEEN THE MEAN TROUGH IN THE EAST AND RIDGE ON THE WEST
COAST. ANOTHER SHORTWAVE TROUGH SWINGS TROUGH LATE TONIGHT/EARLY
THURSDAY MORNING TO GIVE US A SHOT AT SOME FLURRIES...ESPECIALLY
NORTH. SREF INDICATING SOME SPOTTY LOW CHANCES OF ACCUMULATING
PRECIPITATION...BUT LEANING TOWARDS FLURRIES WITH THE DRY LOWER
LEVELS. SOME VORTICITY HOLDS ON LONGER IN THE SOUTH...SO KEPT SOME
SLIGHT CHANCES OF FLURRIES THERE THROUGH THE ENTIRE MORNING.
STRONG COLD AIR ADVECTION IS ADVERTISED AS SURFACE HIGH PRESSURE
BUILDS IN TOMORROW. WITH ANTICIPATED CONSIDERABLE SKY COVER FOR MOST
OF THE DAY AND 18Z 850 MB TEMPS NEAR -20C NEAR ORD TO -10C IN THE
SOUTHERN CWA...TEMPERATURES WILL NOT GO VERY FAR...SO HAVE LOWERED
TEMPERATURES CONSIDERABLY FOR THURSDAY...ESPECIALLY NORTH. THE WIND
WILL BECOME BRISK AGAIN FOR THURSDAY WITH THE STRONG COLD AIR
ADVECTION....WITH PLACES NEAR 0RD APPROACHING -15F IN THE EARLY
MORNING THURSDAY. SNOW PACK MAY HAVE SOME AFFECT ON
TEMPERATURES...BUT MOST OF THE CHILL WILL BE FROM THE COLD AIR
ADVECTION ANTICIPATED.
LONG TERM...THURSDAY EVENING THROUGH NEXT WEDNESDAY. THE SHORT
STORY THROUGH THIS 6-DAY PERIOD IS THAT THE FORECAST REMAINS
PRECIPITATION FREE...ALTHOUGH WILL HAVE TO WATCH FOR THE POTENTIAL
FOR SOME PESKY FLURRIES OR VERY LIGHT SNOW DEVELOPMENT FRIDAY/FRIDAY
NIGHT MAINLY NORTHEAST. OTHERWISE...TEMPERATURES WILL BE A
CONSIDERABLE CHALLENGE ESPECIALLY FRIDAY-SATURDAY AS WARMER AIR
MOVING IN FROM THE WEST STARTS A FIERCE BATTLE WITH THE
RESPECTABLE 1-5 INCH SNOW PACK NOW BLANKETING THE SOUTHEAST 1/2 OF
OUR CWA. OVERALL THOUGH...LEGITIMATELY ABOVE NORMAL TEMPERATURES
IN THE 40S/50S LOOK TO DOMINATE THE EARLY-MIDDLE PART OF NEXT
WEEK.
STARTING OFF THURSDAY NIGHT...MODELS SUCH AS THE 12Z NAM/GFS/ECMWF
ARE IN GOOD AGREEMENT THAT THE VERY BEGINNING STAGES OF MODEST
WARM AIR ADVECTION WILL START GETTING UNDERWAY IN THE LOW
LEVELS...AS THE COLD MID/UPPER TROUGH EDGES FARTHER EAST AWAY FROM
THE CENTRAL PLAINS. AT THE SURFACE...THE CWA WILL BE NEAR OR JUST
WEST OF A FAIRLY STRONG SURFACE RIDGE AXIS CENTERED OVER THE MO
VALLEY THROUGH THE FIRST PART OF THE NIGHT...WHILE SOUTHERLY
BREEZES OF AROUND 10 MPH WILL KICK INTO GEAR LATER IN THE NIGHT IN
THE RETURN FLOW AROUND THE DEPARTING HIGH. AS A RESULT...DEPENDING
ON CLOUD COVER TEMPS COULD REALLY DIP IN THE EVENING BEFORE
EXHIBITING A SLIGHT LATE-NIGHT RISE. CLOUD TRENDS WILL BE A BIT
TRICKY...AS MODELS SHOW THE POTENTIAL FOR A TRANSIENT BAND OF MID
LEVEL SATURATION WORKING ACROSS THE CWA FROM WEST-EAST THROUGH THE
NIGHT. ALTHOUGH ITS NOT OUT OF THE QUESTION A FEW FLURRIES COULD
TRY FORMING FROM THIS...CHANCES LOOK LOW ENOUGH TO LEAVE OUT AT THIS
TIME. AS FOR ACTUAL LOW TEMPS...LOWERED EAST-NORTHEAST ZONES A BIT
FROM PREVIOUS FORECAST. NOW HAVE LOWS DOWN IN THE SINGLE DIGITS
ABOVE ZERO MOST AREAS...EXCEPT FOR A 10-15 RANGE FAR SOUTHWEST
WHERE THE SOUTH WINDS KICK IN A BIT SOONER.
FRIDAY/FRIDAY NIGHT...AS ALREADY MENTIONED WILL NEED TO MONITOR
FOR SOME LOW-IMPACT FLURRY/VERY LIGHT SNOW ACTIVITY ESPECIALLY IN
NORTHEAST COUNTIES AS A LOW AMPLITUDE SHORTWAVE TROUGHS DROPS
OVERHEAD IN WEST-NORTHWEST FLOW ALOFT...BUT WITH THIS STILL BEING 4-5
PERIODS OUT AM CONTENT LEAVING IT OUT FOR NOW...AND LET LATER
SHIFTS TAKE A CLOSER LOOK. NO MATTER WHAT...THE MUCH BETTER FOCUS
FOR POTENTIALLY MEASURABLE SNOW WILL FOCUS WELL EAST INTO IA. HIGH
TEMPS FRIDAY ARE REALLY GOING TO BE A CHALLENGE...ESPECIALLY ALONG
THE INTERFACE BETWEEN THE NEARLY SNOW-FREE GROUND AND THE DEEPER
SNOWPACK. BREEZY SOUTHWEST WINDS SHOULD HAVE NO PROBLEM BOOSTING
ROUGHLY THE WESTERN HALF OF THE CWA WELL INTO THE 40S...WHILE EASTERN
AREAS COULD STAY WELL DOWN IN THE LOW-MID 30S. CONFIDENCE IN THE
MAGNITUDE OF THIS GRADIENT IS FAIRLY LOW AT THIS TIME. LOWS FRIDAY
NIGHT ARE FORECAST QUITE A BIT WARMER THAN THURS NIGHT THANKS TO
DEVELOPING WESTERLY FLOW BEHIND A PASSING TROUGH AXIS...AND HAVE
ALL AREAS HOLDING UP IN THE LOW-MID 20S.
SATURDAY/SATURDAY NIGHT...CONTINUED WEST-NORTHWEST DOWNSLOPE LOW
LEVEL FLOW SHOULD AID THE CONTINUED WARM-UP...AND MADE LITTLE
CHANGE TO HIGHS WITH MOST OF THE CWA REACHING THE MID-UPPER
40S...EXCEPT FOR LOW 40S IN THE FAR SOUTHEAST ESPECIALLY AROUND
HEBRON WHERE THE DEEPER SNOW EXISTS.
SUNDAY/SUNDAY NIGHT...CONFIDENCE REMAINS FAIRLY HIGH IN DRY
CONDITIONS...DESPITE THE PASSAGE OF ANOTHER QUICK MOVING SHORTWAVE
TROUGH IN THE PERSISTENT WEST/NORTHWEST FLOW ALOFT. THE ONLY REAL
IMPACT FROM THIS WAVE AT THE SURFACE WILL BE THE PASSAGE OF
ANOTHER MODEST SURFACE TROUGH MAINLY SUNDAY NIGHT. FOR
HIGHS...ANTICIPATE THAT THE SNOWPACK-EFFECTS SHOULD BE TEMPERED A
BIT VERSUS FRIDAY/SATURDAY...SO HAVE A BIT MORE UNIFORM
TEMPERATURE FIELD...WITH UPPER 40S/LOW 50S MOST AREAS EXCEPT MID
40S IN THE SOUTHEAST.
MONDAY/MONDAY NIGHT...CONTINUED NORTHWESTERLY FLOW ALOFT AS A
BROAD RIDGE STARTS BUILDING EASTWARD OVER THE WESTERN CONUS A BIT.
THE PREFERRED ECWMF SOLUTION KEEPS ANY PRECIP-PRODUCING SHORTWAVE
ENERGY WELL EAST OF THE LOCAL AREA ALONG AN AXIS FROM THE DAKOTAS
THROUGH IA. WITH LITTLE CHANGE IN THE LOW LEVEL TEMP FIELDS...HAVE
HIGHS SIMILAR TO SUNDAY WITH MOST AREAS UPPER 40S TO LOW 50S.
TUESDAY/TUESDAY NIGHT...CONTINUED DRY AS A BRIEF PERIOD OF
MID/UPPER RIDGING TRANSLATES OVERHEAD...AND AGAIN VERY SIMILAR
HIGH TEMPERATURES AS PREVIOUS FEW DAYS WITH UPPER 40S MOST NEB
ZONES AND LOW-MID 50S KS.
WEDNESDAY...STILL NO LEGITIMATE SIGN OF PRECIP...AS MODELS
ADVERTISE FAIRLY UNEVENTFUL QUASI-ZONAL FLOW AT THIS TIME. ONCE
AGAIN...HIGHS RANGING UPPER 40S NORTHEAST TO MID-50S SOUTHWEST.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS HASTINGS NE
956 PM CST WED JAN 30 2013
.UPDATE...EVENING UPPER AIR ANALYSIS PER RAP ANALYSIS DATA
SUGGESTS A LARGE MID AND UPPER LEVEL LONGWAVE TROUGH PERSISTS OVER
THE CENTRAL CONUS. MID AND UPPER LEVEL JET ENERGY EXTENDS
SOUTH/SOUTHEAST ACROSS THE WESTERN CONUS...THEN EAST ACROSS THE
SOUTHERN PLAINS...AND EVENTUALLY NORTHEAST ACROSS THE EASTERN ONE-
THIRD OF THE CONUS. ALTHOUGH MID AND UPPER TROPOSPHERIC FLOW HAS
BEEN FAIRLY WEAK OVER OUR AREA THROUGH THIS EVENING...THE MID
LEVEL WIND FIELD IS INTENSIFYING WITH THE APPROACH OF A ~80KT MID
LEVEL JET STREAK FROM THE NORTHWEST. WATER VAPOR IMAGERY INDICATES
FAIRLY MEAGER MID LEVEL MOISTURE OVER OUR AREA...ALTHOUGH SOME
MODEST INCREASE IN MID LEVEL MOISTURE IS NOTED ADVECTING INTO THE
AREA FROM THE NORTHWEST VIA THE MID LEVEL JET AXIS. A MID LEVEL
SHORT WAVE IS ALSO NOTED OVER PORTIONS OF SOUTHERN MANITOBA AND
SOUTHERN ONTARIO...MOVING SOUTH/SOUTHEAST WITHIN THE MEAN FLOW. AT
THE SURFACE LOW BAROMETRIC PRESSURE IS NOTED OVER PORTIONS OF
CENTRAL NEBRASKA...WITH RAPIDLY INCREASING BAROMETRIC PRESSURE
NOTED UPSTREAM ACROSS THE DAKOTAS AND PORTIONS OF MONTANA. THE LOW
LEVEL WIND FIELD OVER OUR AREA REMAINS FAIRLY LIGHT BUT STILL FROM
THE NORTHWEST FOR THE MOST PART.
GUIDANCE FROM THE NAM...OPERATIONAL GFS...EC...AND SREF-MEAN ALL
SUGGEST THE MID LEVEL SHORT WAVE...CURRENTLY ADVANCING
SOUTH/SOUTHEAST FROM SOUTHERN CANADA...WILL CONTINUE MOVING
SOUTHEAST ACROSS PORTIONS OF THE NORTHERN PLAINS AND UPPER
MISSISSIPPI VALLEY THROUGH THE NEXT 18-24 HOURS. IT APPEARS AS
THOUGH THE PRIMARY AXIS OF OMEGA AHEAD OF THE MID LEVEL TROUGH
AXIS WILL REMAIN NORTHEAST OF OUR AREA...ALTHOUGH THE SOUTHWESTERN
PERIPHERY OF THE MID LEVEL TROUGH AXIS COULD EXTEND JUST FAR
ENOUGH SOUTHWEST TO CLIP NORTHEASTERN PORTIONS OF OUR CWA AND
GENERATE SOME VERY LIGHT PRECIPITATION TONIGHT. FORECAST PROXIMITY
SOUNDINGS FROM ACROSS OUR CWA...PER THE NAM AND OPERATIONAL
GFS...SUGGEST LOW TO MID TROPOSPHERIC MOISTURE WILL LIKELY REMAIN
TOO MEAGER FOR SIGNIFICANT PRECIPITATION PRODUCTION...BUT STILL
CANNOT RULE OUT A FEW SNOW FLURRIES ACROSS OUR NORTHEAST.
OVERALL THE GOING FORECAST IS IN GREAT SHAPE...BUT DID GO AHEAD
AND TRIM THE MENTION OF FLURRIES ACROSS OUR CWA...AND THIS MENTION
IS NOW RELEGATED TO OUR FAR NORTHEASTERN CWA. FORECAST OVERNIGHT
LOWS ALSO LOOK GOOD FOR THE TIME BEING...GENERALLY IN THE TEENS
WITH THURSDAY MORNING APPARENT TEMPERATURE VALUES APPROACHING -10
ACROSS OUR NORTHEAST AROUND SUNRISE. ALL OTHER CHANGES WERE TO
HOURLY TEMPERATURE...WIND...SKY...AND DEWPOINT GRIDS TO BETTER
REFLECT CURRENT CONDITIONS.
&&
.PREV DISCUSSION... /ISSUED 522 PM CST WED JAN 30 2013/
AVIATION...00Z KGRI TAF. VFR CONDITIONS ARE FORECAST THROUGH THE NEXT
24 HOURS. SCATTERED TO BROKEN CLOUDS NEAR 3500FT AGL ARE EXPECTED
AS A MID LEVEL SHORT WAVE CLIPS THE AREA TO THE NORTHEAST. ONE SET
OF GUIDANCE DOES SUGGEST A PERIOD OF MVFR CEILINGS COULD BE
REALIZED AT THE TERMINAL TONIGHT...BUT CONFIDENCE IN MVFR
CONDITIONS ACTUALLY BEING REALIZED AT KGRI IS TOO LOW TO PRESENT
IN THE TAF AT THIS TIME. THE SURFACE WIND WILL REMAIN FROM THE
NORTHWEST AND INTENSIFY DURING THE TAF PERIOD...SUSTAINED NEAR
19KTS AND GUSTING NEAR 28KTS DURING THE DAY THURSDAY. VISIBILITY
RESTRICTION WILL NOT BE OBSERVED AT THE TERMINAL THROUGH THE NEXT
24 HOURS.
PREV DISCUSSION... /ISSUED 423 PM CST WED JAN 30 2013/
SHORT TERM...TONIGHT AND THURSDAY. WE WILL BE WITHIN NORTHWEST
FLOW...BETWEEN THE MEAN TROUGH IN THE EAST AND RIDGE ON THE WEST
COAST. ANOTHER SHORTWAVE TROUGH SWINGS TROUGH LATE TONIGHT/EARLY
THURSDAY MORNING TO GIVE US A SHOT AT SOME FLURRIES...ESPECIALLY
NORTH. SREF INDICATING SOME SPOTTY LOW CHANCES OF ACCUMULATING
PRECIPITATION...BUT LEANING TOWARDS FLURRIES WITH THE DRY LOWER
LEVELS. SOME VORTICITY HOLDS ON LONGER IN THE SOUTH...SO KEPT SOME
SLIGHT CHANCES OF FLURRIES THERE THROUGH THE ENTIRE MORNING.
STRONG COLD AIR ADVECTION IS ADVERTISED AS SURFACE HIGH PRESSURE
BUILDS IN TOMORROW. WITH ANTICIPATED CONSIDERABLE SKY COVER FOR MOST
OF THE DAY AND 18Z 850 MB TEMPS NEAR -20C NEAR ORD TO -10C IN THE
SOUTHERN CWA...TEMPERATURES WILL NOT GO VERY FAR...SO HAVE LOWERED
TEMPERATURES CONSIDERABLY FOR THURSDAY...ESPECIALLY NORTH. THE WIND
WILL BECOME BRISK AGAIN FOR THURSDAY WITH THE STRONG COLD AIR
ADVECTION....WITH PLACES NEAR 0RD APPROACHING -15F IN THE EARLY
MORNING THURSDAY. SNOW PACK MAY HAVE SOME AFFECT ON
TEMPERATURES...BUT MOST OF THE CHILL WILL BE FROM THE COLD AIR
ADVECTION ANTICIPATED.
LONG TERM...THURSDAY EVENING THROUGH NEXT WEDNESDAY. THE SHORT
STORY THROUGH THIS 6-DAY PERIOD IS THAT THE FORECAST REMAINS
PRECIPITATION FREE...ALTHOUGH WILL HAVE TO WATCH FOR THE POTENTIAL
FOR SOME PESKY FLURRIES OR VERY LIGHT SNOW DEVELOPMENT FRIDAY/FRIDAY
NIGHT MAINLY NORTHEAST. OTHERWISE...TEMPERATURES WILL BE A
CONSIDERABLE CHALLENGE ESPECIALLY FRIDAY-SATURDAY AS WARMER AIR
MOVING IN FROM THE WEST STARTS A FIERCE BATTLE WITH THE
RESPECTABLE 1-5 INCH SNOW PACK NOW BLANKETING THE SOUTHEAST 1/2 OF
OUR CWA. OVERALL THOUGH...LEGITIMATELY ABOVE NORMAL TEMPERATURES
IN THE 40S/50S LOOK TO DOMINATE THE EARLY-MIDDLE PART OF NEXT
WEEK.
STARTING OFF THURSDAY NIGHT...MODELS SUCH AS THE 12Z NAM/GFS/ECMWF
ARE IN GOOD AGREEMENT THAT THE VERY BEGINNING STAGES OF MODEST
WARM AIR ADVECTION WILL START GETTING UNDERWAY IN THE LOW
LEVELS...AS THE COLD MID/UPPER TROUGH EDGES FARTHER EAST AWAY FROM
THE CENTRAL PLAINS. AT THE SURFACE...THE CWA WILL BE NEAR OR JUST
WEST OF A FAIRLY STRONG SURFACE RIDGE AXIS CENTERED OVER THE MO
VALLEY THROUGH THE FIRST PART OF THE NIGHT...WHILE SOUTHERLY
BREEZES OF AROUND 10 MPH WILL KICK INTO GEAR LATER IN THE NIGHT IN
THE RETURN FLOW AROUND THE DEPARTING HIGH. AS A RESULT...DEPENDING
ON CLOUD COVER TEMPS COULD REALLY DIP IN THE EVENING BEFORE
EXHIBITING A SLIGHT LATE-NIGHT RISE. CLOUD TRENDS WILL BE A BIT
TRICKY...AS MODELS SHOW THE POTENTIAL FOR A TRANSIENT BAND OF MID
LEVEL SATURATION WORKING ACROSS THE CWA FROM WEST-EAST THROUGH THE
NIGHT. ALTHOUGH ITS NOT OUT OF THE QUESTION A FEW FLURRIES COULD
TRY FORMING FROM THIS...CHANCES LOOK LOW ENOUGH TO LEAVE OUT AT THIS
TIME. AS FOR ACTUAL LOW TEMPS...LOWERED EAST-NORTHEAST ZONES A BIT
FROM PREVIOUS FORECAST. NOW HAVE LOWS DOWN IN THE SINGLE DIGITS
ABOVE ZERO MOST AREAS...EXCEPT FOR A 10-15 RANGE FAR SOUTHWEST
WHERE THE SOUTH WINDS KICK IN A BIT SOONER.
FRIDAY/FRIDAY NIGHT...AS ALREADY MENTIONED WILL NEED TO MONITOR
FOR SOME LOW-IMPACT FLURRY/VERY LIGHT SNOW ACTIVITY ESPECIALLY IN
NORTHEAST COUNTIES AS A LOW AMPLITUDE SHORTWAVE TROUGHS DROPS
OVERHEAD IN WEST-NORTHWEST FLOW ALOFT...BUT WITH THIS STILL BEING 4-5
PERIODS OUT AM CONTENT LEAVING IT OUT FOR NOW...AND LET LATER
SHIFTS TAKE A CLOSER LOOK. NO MATTER WHAT...THE MUCH BETTER FOCUS
FOR POTENTIALLY MEASURABLE SNOW WILL FOCUS WELL EAST INTO IA. HIGH
TEMPS FRIDAY ARE REALLY GOING TO BE A CHALLENGE...ESPECIALLY ALONG
THE INTERFACE BETWEEN THE NEARLY SNOW-FREE GROUND AND THE DEEPER
SNOWPACK. BREEZY SOUTHWEST WINDS SHOULD HAVE NO PROBLEM BOOSTING
ROUGHLY THE WESTERN HALF OF THE CWA WELL INTO THE 40S...WHILE EASTERN
AREAS COULD STAY WELL DOWN IN THE LOW-MID 30S. CONFIDENCE IN THE
MAGNITUDE OF THIS GRADIENT IS FAIRLY LOW AT THIS TIME. LOWS FRIDAY
NIGHT ARE FORECAST QUITE A BIT WARMER THAN THURS NIGHT THANKS TO
DEVELOPING WESTERLY FLOW BEHIND A PASSING TROUGH AXIS...AND HAVE
ALL AREAS HOLDING UP IN THE LOW-MID 20S.
SATURDAY/SATURDAY NIGHT...CONTINUED WEST-NORTHWEST DOWNSLOPE LOW
LEVEL FLOW SHOULD AID THE CONTINUED WARM-UP...AND MADE LITTLE
CHANGE TO HIGHS WITH MOST OF THE CWA REACHING THE MID-UPPER
40S...EXCEPT FOR LOW 40S IN THE FAR SOUTHEAST ESPECIALLY AROUND
HEBRON WHERE THE DEEPER SNOW EXISTS.
SUNDAY/SUNDAY NIGHT...CONFIDENCE REMAINS FAIRLY HIGH IN DRY
CONDITIONS...DESPITE THE PASSAGE OF ANOTHER QUICK MOVING SHORTWAVE
TROUGH IN THE PERSISTENT WEST/NORTHWEST FLOW ALOFT. THE ONLY REAL
IMPACT FROM THIS WAVE AT THE SURFACE WILL BE THE PASSAGE OF
ANOTHER MODEST SURFACE TROUGH MAINLY SUNDAY NIGHT. FOR
HIGHS...ANTICIPATE THAT THE SNOWPACK-EFFECTS SHOULD BE TEMPERED A
BIT VERSUS FRIDAY/SATURDAY...SO HAVE A BIT MORE UNIFORM
TEMPERATURE FIELD...WITH UPPER 40S/LOW 50S MOST AREAS EXCEPT MID
40S IN THE SOUTHEAST.
MONDAY/MONDAY NIGHT...CONTINUED NORTHWESTERLY FLOW ALOFT AS A
BROAD RIDGE STARTS BUILDING EASTWARD OVER THE WESTERN CONUS A BIT.
THE PREFERRED ECWMF SOLUTION KEEPS ANY PRECIP-PRODUCING SHORTWAVE
ENERGY WELL EAST OF THE LOCAL AREA ALONG AN AXIS FROM THE DAKOTAS
THROUGH IA. WITH LITTLE CHANGE IN THE LOW LEVEL TEMP FIELDS...HAVE
HIGHS SIMILAR TO SUNDAY WITH MOST AREAS UPPER 40S TO LOW 50S.
TUESDAY/TUESDAY NIGHT...CONTINUED DRY AS A BRIEF PERIOD OF
MID/UPPER RIDGING TRANSLATES OVERHEAD...AND AGAIN VERY SIMILAR
HIGH TEMPERATURES AS PREVIOUS FEW DAYS WITH UPPER 40S MOST NEB
ZONES AND LOW-MID 50S KS.
WEDNESDAY...STILL NO LEGITIMATE SIGN OF PRECIP...AS MODELS
ADVERTISE FAIRLY UNEVENTFUL QUASI-ZONAL FLOW AT THIS TIME. ONCE
AGAIN...HIGHS RANGING UPPER 40S NORTHEAST TO MID-50S SOUTHWEST.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
0956 PM UPDATE/AVIATION...BRYANT
SHORT TERM...HEINLEIN
LONG TERM...PFANNKUCH
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
332 AM EST THU JAN 31 2013
.SYNOPSIS...
COLDER AIR WORKING INTO THE AREA BEHIND A STRONG COLD FRONT WILL
PRODUCE STRONG GUSTY WINDS TODAY...IN ADDITION TO LAKE EFFECT
SNOWS DOWNWIND OF LAKES ERIE AND ONTARIO. BELOW NORMAL
TEMPERATURES AND SCATTERED SHOW SHOWERS WILL CONTINUE INTO THE
WEEKEND...DUE TO A COMBINATION OF LAKE EFFECT SNOW SHOWERS AND
WEAK UPPER LEVEL DISTURBANCES.
&&
.NEAR TERM /THROUGH TONIGHT/...
BACKEDGE OF AREA OF STEADY RAIN AREA MOVING INTO WRN ZONES AS OF
315 AM...CLOSE TO THE PSN OF THE SFC CDFNT...AND WILL CONTINUE IT`S EWD
PROGRESS THROUGH THE EARLY MRNG HRS. SOME OF THE RAIN MAY MIX
BRIEFLY WITH SNOW BEFORE TAPERING OFF THIS MRNG. FLOOD WATCH
REMAINS ON EFFECT...WE HAVE ISSUED SOME FLS`S THUS FAR AND WILL
CONTINUE TO MONITOR CAREFULLY.
MAIN ISSUE TDA WILL BE THE STRONG WINDS DVLPNG THIS MRNG AND
CONTINUING INTO THE AFTN HRS. BASED ON OUR SUSTAINED AND PEAK WIND
GRIDS...WE ADDED STEUBEN...YATES AND SENECA COUNTIES INTO THE
WARNING.
SCATTERED SNOW SHOWERS ARE XPCTD TDA...MAILY DUE TO LAKE
INFLUENCES. WE COULD SEE -SHSN OFF LAKE ERIE ACRS PORTIONS OF THE
TWIN TIERS THIS AFTN/EVNG. POTNL FOR 2-4 INCHES ACRS PORTIONS OF
WRN STEUBEN TNGT. AFTN SHIFT CAN RE-ASSESS AND DETERMINE IF A LOW
END ADVISORY IS NEEDED HERE.
AS FOR THE NRN ONEIDA LES EVENT...THIS EVENT APPEARS TO BE SIMILAR
TO LAST WEEKS. THE ARW PERFORMED WELL IN THAT CASE...AND THIS
MRNG`S RUC ALSO SHOWS GOOD AGREEMENT EARLY ON IN THE PD. IT
APPEARS THAT THE BAND WILL NOT MAKE A MOVE INTO NRN ONEIDA UNTIL
LATE THIS AFTN...PERSISTING OVER THAT AREA TIL ARND 06Z BEFORE
DROPPING SWD AS FLOW BCMS MORE WNWLY. AS THIS OCCURS...MESO MDLS
SHOW THE BAND OVER LAKE ONTARIO DROPPING TO A PSN NEAR/ALONG THE
SRN SHORE OF LAKE ONTARIO LATE TNGT/TWDS DAYBREAK. THIS IS WHAT
OCCURRED WITH THE LAST BAND...AND RESULTED IN RAPID WEAKENING OF
TEH BAND OVER THE BGM CWA DUE (AT LEAST IN PART) TO THE LOSS OF
OVER-LAKE TRAJECTORY. THIS IS ALSO HINTED AT IN THE MESO MDLS FRI
MRNG. FOR NOW WE HAVE THE BAND DROPPING SWD INTO ONON/MAD IN THE
09-12Z TIME FRAME...WITH POTNL FOR LOW END ADVISORY ACCUMS MAINLY
OVER NW ONON. GIVEN THE NUMEROUS HEADLINES ALREADY IN EFFECT AND
THE FACT WE HAVE SOME TIME TO TAKE A CLOSER LOOK AT THIS...WE WILL
JUST MENTION THE POTNL IN THE HWO AND LET THE DAYSHIFT ISSUE
HEADLINES FOR THIS EVENT IF NEEDED.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
A COUPLE OF CLIPPER-TYPE SYSTEMS WILL AFFECT THIS WEEKEND...WITH
SCATTERED SNOW SHOWERS. A MORE WDSPRD AREA OF LGT SNOW COULD DVLP
IN THE WARM ADVECTION PTRN AHEAD OF THE CLIPPER APRCHNG SAT NGT.
IN GNRL...CHC POPS FOR -SHSN AND BLO NORMAL TEMPS.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
GRIDS WERE ADJUSTED SOME TO ACCOUNT FOR LATEST HPC GUIDANCE AND
GFS/ECMWF MODELS. NO BIG CHANGE TO GOING FORECAST OVERALL...BUT I
DID UPGRADE POPS INTO LIKELY CATEGORY FOR CENTRAL NY AND AT LEAST
HIGHER CHANCE FOR NORTHEAST PA SUNDAY WITH FAIR AGREEMENT ON BEING
INVOLVED IN MERGER BETWEEN DEVELOPING COASTAL LOW AND INCOMING
NORTHERN STREAM SYSTEM/CLIPPER. COULD EASILY RESULT IN LIGHT
COATING OF SNOW. ANOTHER WEAK CLIPPER CONTINUES TO LOOK POSSIBLE
MONDAY NIGHT/TUESDAY.
PREVIOUS DISCUSSION...
FOLLOWED HPC GUIDANCE. MODELS ARE SIMILAR WITH NO LARGE STORMS.
REMAIN UNDER A NORTHEAST US UPPER LEVEL TROF. SEASONABLE WEATHER
WITH WEAK LOW PRESSURE SYSTEMS FOLLOWED BY LAKE EFFECT. ALL PRECIP
WILL BE SNOW WITH HIGHS AROUND 30 AND LOWS IN THE TEENS. THE WEAK
SYSTEMS GO THROUGH SUNDAY AND MONDAY NIGHT...WITH LAKE EFFECT ON
THE OTHER DAYS. COULD BE A 12 HOUR DRY BREAK BETWEEN SYSTEMS WITH
WEAK HIGH PRESSURE MON AFTN.
&&
.AVIATION /08Z THURSDAY THROUGH MONDAY/...
06Z UPDATE...
STRONG WET SYSTEM IS PROGRESSING THROUGH THE REGION. SSE WIND
AHEAD OF THE FRONT...WITH STRONG SSW FLOW NOT FAR OFF THE SURFACE.
FOR KRME AND KAVP...LIKELY MEETING LLWS THRESHOLD AND THUS
INCLUDED INITIALLY IN TAFS. HOWEVER...SURFACE WIND WILL ABRUPTLY
SHIFT TO SW WITH BRIEF HEAVY SHOWERS AS FRONT PASSES...WITH TIMING
AS INDICATED IN TAFS. THOUGH IFR NOT OUT OF QUESTION WITH
FRONT...MAINLY MVFR IS ANTICIPATED AND HAS OCCURRED UPSTREAM.
BEHIND FRONT...WINDS WILL HAVE A MUCH EASIER TIME MIXING
DOWN...MITIGATING ANY FURTHER LLWS BUT ALSO ALLOWING GUSTS
FREQUENTLY IN THE 30-40 KT RANGE. KSYR-KRME COULD EVEN GET A BIT
HIGHER THAN THAT THIS AFTERNOON. SCT-BKN CLOUD DECK DURING THE
DAYTIME HOURS...EVENTUALLY WITH SCT -SHSN AND MVFR CIG FOR SOME
TERMINALS. LAKE ONTARIO SNOW BAND WILL AT FIRST DEVELOP NORTH OF
THE AREA THIS AFTERNOON...BUT SHOULD EDGE SOUTH ENOUGH TO INVOLVE
KRME IN OCCASIONAL IFR VIS 00Z-06Z FRIDAY...AND NOT LONG AFTER
THAT FOR KSYR.
.OUTLOOK...
LATE THU NGT THRU SAT NGT...MVFR-IFR FROM LAKE -SHSN IN CENTRAL NY.
SUN...A COLD FRONT WITH POSSIBLE MVFR AND IFR SNOW
SUN NGT-MON...MORE MVFR/IFR LAKE -SHSN MAINLY CENTRAL NY.
&&
.HYDROLOGY...
CONSENSUS OF MODEL AND MAN MADE GUID PROGS PUTS 1 TO UP TO 2.5
INCHES WITH THE HEAVIEST RAIN AXIS FURTHER WEST ACROSS THE FINGER
LAKES AND CHEMUNG BASINS OF NY. WILL HAVE TWO BATCHES WITH THE
INITIAL BATCH ALREADY IN WRN PA AND WRN NY NOW. THIS FIRST BATCH
MOVES QUICKLY THROUGH THIS AFTN. RAINFALL THIS AFTN UP TO HALF AN
INCH. QUICK RESPONSE ON STREAMS BUT NO FLOODING INITIALLY. THE
COLD FRONT WILL COME THROUGH LATE EVE AND EARLY MORNING WITH MORE
HEAVY RAIN. ANOTHER QUICK INCH IN LESS THAN 6 HOURS WHICH WILL BE
MOSTLY RUNOFF. STREAMS AND RIVERS WILL RESPOND QUICKLY. FLASH
FLOODING POSSIBLE...FOLLOWED BY MINOR RIVER FLOODING.
FLOOD WATCH CONTINUES FOR ENTIRE CWA STARTING AT 4 PM INTO
THURSDAY MORNING. RIVER FLOOD WARNINGS JUST ISSUED FOR
WEST BRANCH DELAWARE RIVER AT WALTON
TIOUGHNIOGA RIVER AT CORTLAND
CHENANGO RIVER AT SHERBURNE
SUSQUEHANNA RIVER AT VESTAL
SUSQUEHANNA RIVER AT WAVERLY/SAYRE
SUSQUEHANNA RIVER AT TOWANDA
SUSQUEHANNA RIVER AT MESHOPPEN
SUSQUEHANNA RIVER NEAR WILKES-BARRE
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...FLOOD WATCH UNTIL 7 AM EST THIS MORNING FOR PAZ038>040-043-044-
047-048-072.
WIND ADVISORY UNTIL 7 PM EST THIS EVENING FOR PAZ038>040-043-
044-047-048-072.
NY...FLOOD WATCH UNTIL 7 AM EST THIS MORNING FOR NYZ009-015>018-
022>025-036-037-044>046-055>057-062.
WIND ADVISORY UNTIL 7 PM EST THIS EVENING FOR NYZ023>025-044-
045-055-056-062.
HIGH WIND WARNING UNTIL 7 PM EST THIS EVENING FOR NYZ009-
015>018-022-036-037-046-057.
LAKE EFFECT SNOW WARNING FROM 1 PM THIS AFTERNOON TO 7 AM EST
FRIDAY FOR NYZ009.
&&
$$
LONG TERM...MDP/TAC
AVIATION...MDP
HYDROLOGY...
AREA FORECAST DISCUSSION
NWS BUFFALO NY
1157 PM EST WED JAN 30 2013
.SYNOPSIS...
RAIN...HEAVY AT TIMES WILL FALL ACROSS THE REGION TONIGHT AHEAD OF A
COLD FRONT THAT WILL SWEEP ACROSS THE REGION WHICH WILL SEND
TEMPERATURES BACK TO SEASONAL NORMALS. AS THE COLD AIR DEEPENS ON
THURSDAY...LAKE EFFECT SNOWS WILL SET UP IN THE TRADITIONAL
SNOWBELTS EAST AND SOUTHEAST OF THE LAKES...THEN WILL CONTINUE
THROUGH THE END OF THE WEEK.
&&
.NEAR TERM /THROUGH THURSDAY/...
LOW PRESSURE ACROSS LAKE HURON WILL LIFT NORTHEAST ACROSS SOUTHERN
ONTARIO OVERNIGHT. THIS WILL BRING A COLD FRONT ACROSS THE REGION
TONIGHT...FORECAST TO ENTER FAR WESTERN NEW YORK AROUND
MIDNIGHT...THEN SWEEP RAPIDLY TO THE EAST THROUGH THE EARLY
MORNING HOURS. THIS WILL CAUSE AN ABRUPT DROP IN TEMPERATURES...AND
KEY THE ONSET IN GUSTY WINDS. EXPECT WIND GUSTS WILL PUSH 50 MPH
IMMEDIATELY BEHIND THE FRONT...BEFORE THE STEADIER WINDS AHEAD OF
A SECONDARY SHOT OF COLDER AIR.
IN ADDITION....THIS SYSTEM WILL SET UP A DEEP SOUTHERLY FLOW OUT
AHEAD OF IT...WHICH WILL TRANSPORT MOISTURE FROM PENNSYLVANIA AND
INTO CENTRAL NEW YORK TONIGHT. A BLEND OF RADAR AND HRRR MODEL
GUIDANCE THROUGH 1100 PM SUGGEST THE HEAVIEST RAINS WILL SLIDE A
BIT FURTHER EAST...MAINLY IMPACTING LOCATIONS EAST OF LAKE
ONTARIO. BECAUSE OF THIS...HAVE MODIFIED THE FLOOD WATCH. REFER TO
THE HYDROLOGY SECTION FOR MORE ON THIS.
THE SYSTEM WILL CAUSE MULTIPLE ISSUES FOR THE CWA...ORGANIZED BY
IMPACT BELOW.
1. STRONG WINDS...THE AFOREMENTIONED STORM SYSTEM WILL DEEPEN FROM
AROUND 985MB 00Z TONIGHT TO 970MB 12Z TOMORROW MORNING JUST NORTH OF
VERMONT...AND THEN BELOW 960 MB BY 00Z FRIDAY ACROSS EASTERN QUEBEC.
THIS RAPID DEEPENING...COMBINED WITH 6 TO 8 MB ISALLOBARIC PRESSURE
RISES WITHIN COLD AIR ADVECTION FOLLOWING THE COLD FRONT SHOULD BE
ABLE TO MIX A 50 KNOT JET AT 925 HPA DOWN TO THE SURFACE. GIVEN THE
STRONG AND VERY DYNAMIC NATURE OF THIS SYSTEM...ITS ASSOCIATED WIND
FIELDS WILL ALSO BE QUITE STRONG. WE WILL UPGRADE THE ADVISORY TO A
WARNING FOR A GOOD PORTION OF THE CWA. WIND GUSTS UP TO 60 MPH ARE
LIKELY IN FAVORED AREAS ALONG THE LAKE ERIE SHORELINE INLAND ACROSS
SOUTHERN LAKE ONTARIO AND THROUGH THE EASTERN LAKE ONTARIO REGION.
FOR OUR INLAND COUNTIES OF WYOMING...ALLEGANY...LIVINGSTON AND
ONTARIO WE WILL LEAVE A HIGH END WIND ADVISORY AS THE DEEPENING LOW
MAY BE TOO FAR NORTH TO ALLOW FOR WARNING CRITERIA WINDS HERE.
2. LAKE EFFECT SNOW...FOLLOWING THE PASSAGE OF THE COLD FRONT -14C
TO -16C 850 HPA AIR TEMPERATURES WILL BE CROSSING THE LAKES. AT
FIRST WINDS MAY BE TO STRONG FOR GOOD FORMATION OF LAKE EFFECT SNOW
BANDS WITH THE WINDS SHEARING AWAY THE LAKE BAND FORMATION. ALSO
WITH THE STRONG WINDS RESIDENT TIME OVER THE LAKE BODIES WILL BE
LIMITED. AS WINDS DIMINISH THROUGH THE AFTERNOON AND COLD AIR
DEEPENS...AND LAKE INDUCED EQUILIBRIUM LEVELS RISE TOWARDS 7 TO 9K
FEET A BAND OF SNOW SHOULD BE FORMING OFF BOTH LAKE ERIE AND LAKE
ONTARIO. THE NAM...AND TO A DEGREE THE GFS HAS DEEP SYNOPTIC
MOISTURE REMAINING IN THE SNOW GROWTH ZONE...WHICH WILL BE FALLING
WITH THE COLD AIR ADVECTION.
OFF LAKE ONTARIO...WIND FIELD CONVERGENCE OVER LAKE ONTARIO IS
LEADING TO IMPRESSIVE OMEGA FIELDS BY THURSDAY AFTERNOON WHERE A
BAND OF LAKE EFFECT SNOW MAY BEGIN TO PRODUCE SNOWFALL RATES UP TO 2
INCHES PER HOUR. FOLLOWING THE SURFACE LOW AND UPPER LEVEL TROUGH
WINDS WILL BEGIN TO VEER THROUGH THE DAY DROPPING THE LAKE EFFECT
SNOW BAND SOUTH OF JEFFERSON COUNTY. FOR THIS REASON WILL LEAVE
JEFFERSON COUNTY AS A HIGH END LAKE EFFECT SNOW ADVISORY...AND HAVE
WARNINGS FOR LEWIS AND OSWEGO COUNTIES WHERE THE BAND WILL LIKELY
FALL LONGER.
OFF LAKE ERIE...A WESTERLY FLOW OVER THE STILL OPEN WATERS OF LAKE
ERIE WILL BRING MULTI BANDED STRUCTURE SNOW BANDS ACROSS THE SOUTHERN
TIER. CONFIDENCE IS GREATER ACROSS CHAUTAUQUA AND CATTARAUGUS COUNTIES
THAN SOUTHERN ERIE AND WYOMING COUNTIES FOR WARNING CRITERIA SNOW.
WILL UPGRADE THE WATCH TO A LAKE EFFECT WARNING ACROSS THE SOUTHERN
TIER...WHILE LEAVING ADVISORIES FOR SOUTHERN TIER AND WYOMING
COUNTIES.
3. REGARDING TEMPERATURES...RECORDED HIGHS WERE SHATTERED ACROSS
MUCH OF THE REGION TODAY WITH MORNING AND EARLY AFTERNOON HIGHS
REACHING NEAR 10 DEGREES ABOVE RECORD VALUES FOR THE DATE.
THE NEW RECORDS FOR TODAY...
BUFFALO.....66 (PREVIOUS WAS 56 IN 1916)
ROCHESTER...64 (PREVIOUS WAS 55 IN 1974)
WATERTOWN...63 (PREVIOUS WAS 52 IN 1995)
THESE READINGS ARE STILL SEVERAL DEGREES SHY OF THE ALLTIME
MONTHLY RECORD HIGH TEMPERATURE WHICH ARE AS FOLLOWS:
BUFFALO.....72 IN 1950.
ROCHESTER...74 IN 1950...CORRECTED
WATERTOWN...66 IN 1995.
THE COLD FRONT WILL SWEEP ACROSS THE REGION TONIGHT SENDING
TEMPERATURES BACK TO SEASONAL NORMS...WITH MANY AREAS DOWN INTO THE
UPPER 20S AND LOW 30S BY TOMORROW MORNING. WITH THE RAIN OVERNIGHT
THE PROSPECTS FOR BLACK ICE WILL BE PRESENT AS WE QUICKLY COOL
FURTHER INTO THE MID AND UPPER 20S BY MID MORNING.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
HEAVY LAKE EFFECT SNOWS SHOULD BE ONGOING ON A WESTERLY FLOW
REGIME AT THE START OF THE PERIOD. BUFR PROFILES FROM THURSDAY
NIGHT THROUGH AT LEAST THE DAYTIME HOURS OF FRIDAY CONTINUE TO
LOOK RATHER IMPRESSIVE...AS A DEEP LAYERED CYCLONIC FLOW REGIME IS
WELL ESTABLISHED. MOISTURE PROFILES LOOK QUITE ADEQUATE WITH
SATURATION WELL UP THROUGH 10K FEET AND DEEPER AT TIMES AS A
COUPLE OF REINFORCING WEAK SHORTWAVES WORK THROUGH THE MEAN WEST
NORTHWEST FLOW. THE BIGGEST FACTOR THAT COULD LIMIT TOTALS WILL BE
THE VEERING WINDS IN RESPONSE TO A SHORTWAVE CROSSING THE LOWER
LAKES. THIS WILL TEND TO PUSH THE LAKE BANDS...ESPECIALLY ACROSS
LAKE ONTARIO SOUTHWARD. THIS COULD BRING THE PRIME LAKE EFFECT
FOCUS ALONG THE SOUTH SHORE OF LAKE ONTARIO...WHICH COULD BRING AT
LEAST ADVISORY OR GREATER TOTALS TO THIS AREA INCLUDING THE
ROCHESTER METRO AREA. FEEL A BIT MORE CONFIDENT WITH THE AREA FROM
WAYNE OVER TO NORTHERN CAYUGA AT THIS POINT...THEREFORE WILL ISSUE
A LAKE EFFECT SNOW WATCH FOR THAT AREA...BUT IT IS HIGHLY POSSIBLE
THAT LAKE EFFECT HEADLINES MAY NEED TO BE ISSUED FARTHER TO THE
WEST.
ANOTHER SHORTWAVE APPROACHING THE REGION FRIDAY NIGHT AND SATURDAY
MAY REORIENT THE LAKES SNOWS FOR A TIME NORTHWARD AS THE FLOW
BACKS TO WEST SOUTHWEST...POTENTIALLY BRINGING SOME ACCUMULATING
SNOWS INTO PORTIONS OF THE BUFFALO METRO AND WATERTOWN AREAS. THE
PASSAGE OF THE SHORTWAVE SHOULD RE-ESTABLISH THE LAKE SNOWS BACK
SOUTHWARD LATER SATURDAY AND SATURDAY NIGHT.
MUCH COLDER AIR MASS ACROSS THE AREA FRIDAY AND SATURDAY WITH
DAYTIME HIGHS IN THE TEENS AND 20S...WITH WIND CHILLS PERIODICALLY
BELOW ZERO.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
THE VERY COLD AIR REMAINS IN PLACE SUNDAY...BEFORE A GRADUAL
MODIFICATION OF THE AIR MASS OCCURS INTO EARLY NEXT WEEK AS THE
UPPER TROUGH SHIFTS TO THE EAST. TWO CLIPPER TYPE WAVES LOOK TO
IMPACT THE LOWER LAKES REGION DURING THIS TIME FRAME. ONE WAVE MOVES
THROUGH ON SUNDAY WHICH MAY SERVE TO ENHANCE THE ONGOING LAKE EFFECT
SNOWS IN A WESTERLY FLOW REGIME. THE SECOND WAVE LOOKS TO MOVE
THROUGH LATE MONDAY OR EARLY TUESDAY AND APPEARS TO BE RATHER ROBUST
AND GIVEN THE PROJECTED TRACK OF THE ASSOCIATED SURFACE LOW COULD
BRING THE POTENTIAL FOR A GENERAL WIDESPREAD SEVERAL INCHES OF SNOW.
BEHIND THIS WAKE A COLDER FLOW DEVELOPS WHICH MAY REDEVELOP SOME
LAKE SNOWS BUT LACK OF SIGNIFICANT MOISTURE COULD LIMIT SNOWFALL
POTENTIAL.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
A COLD FRONT ACROSS BUF/IAG/JHW AT 06Z WILL RACE TO THE
EAST...REACHING ART AROUND 09Z. THIS FRONT WILL TRIGGER AN ABRUPT
INCREASE IN WINDS...WHICH WILL LAST THROUGH MUCH OF THE
DAY...BEFORE TAPERING OFF LATE THURSDAY AFTERNOON.
MEANWHILE...RAIN SHOWER AHEAD OF THE FRONT WILL CONTINUE TO SLIDE
EAST DURING THE EARLY MORNING HOURS. TEMPERATURES WILL COOL BEHIND
THE FRONT...WHICH WILL SET UP LAKE SNOWS EAST OF THE LAKES. THESE
SHOULD LARGELY MISS BUF/IAG/ROC FOR MOST OF TODAY AND THIS
EVENING. LAKE SNOWS WILL PROBABLY IMPACT JHW/ART FOR A
PERIOD...WITH IFR OR LOWER CONDITIONS POSSIBLE.
OUTLOOK...
THURSDAY NIGHT THROUGH SATURDAY...MVFR WITH LOCALIZED IFR IN LAKE
EFFECT SNOW EAST OF THE LAKES.
SUNDAY...MAINLY VFR WITH MVFR IN LOCALIZED LAKE EFFECT SNOW SHOWERS.
MONDAY...VFR.
&&
.MARINE...
A COMPLEX AREA OF LOW PRESSURE FROM SOUTHERN CANADA AND THROUGH THE
CENTRAL GREAT LAKES REGION THIS AFTERNOON WILL LIFT NORTHEASTWARD
AND DEEPEN TONIGHT AND TOMORROW. A COLD FRONT SWINGING ACROSS THE
LAKES...COUPLED WITH STRONG COLD AIR ADVECTION AND RAPID DEEPENING
OF THE SURFACE LOW WILL INCREASE WINDS QUICKLY TO GALE FORCE
FOLLOWING THE PASSAGE OF THE FRONT TONIGHT...WITH GALES THEN
CONTINUING THROUGH MUCH OF THURSDAY. FOR THIS REASON...GALE WARNINGS
WILL CONTINUE AS OUTLINED ON THE LAKES. WINDS AND WAVES WILL STILL
REMAIN STRONG THURSDAY EVENING THROUGH SATURDAY...BEFORE DIMINISHING
TO BELOW SMALL CRAFT CONDITIONS BY SATURDAY NIGHT.
&&
.HYDROLOGY...
FOLLOWING A BLEND OF RADAR AND NEAR TERM GUIDANCE...IT APPEARS THE
STEADIEST RAINS WILL FALL EAST OF LAKE ONTARIO...WITH LESSER
AMOUNTS WEST OF THE GENESEE RIVER. EAST OF LAKE ONTARIO...EXPECT
AROUND AN INCH OF RAIN TO FALL...WITH LESS THAN THAT WEST OF THE
GENESEE. LATEST RFC FORECASTS HAVE LOWERED CRESTS AT
WELLSVILLE...WITH THE MAJORITY OF MMEFS GUIDANCE KEEPING THE
BUFFALO CREEKS...GENESEE RIVER...AND ALLEGHENY RIVER BELOW FLOOD
STAGE. THERE STILL MAY BE A FEW LINGERING ICE JAMS IN TYPICALLY
FLOOD PRONE AREAS IN PARTS OF CHAUTAUQUA COUNTY.
THERE STILL A THREAT FOR FLOODING IN EASTERN PORTIONS...WHERE AN
INCH OF RAINFALL STILL APPEARS LIKELY. LOCALLY HIGHER AMOUNTS FROM
CONVECTION AND/OR UPSLOPING MAY ALSO OCCUR. THIS COMBINED WITH
SNOW MELT FROM LOCATIONS EAST OF LAKE ONTARIO WILL RESULT IN
SIGNIFICANT RISES IN THE RIVERS AND CREEKS. AN INCH OF RAIN IS
STILL MARGINAL TO CAUSE FLOODING...BUT WITH SNOW MELT QUITE
DIFFICULT TO FORECAST...AND SOME ICE JAMS POSSIBLE...THERE IS A
CONTINUED RISK OF FLOODING. THE SREF AND TO A LESSER EXTENT GFS/GGEM
BASED MMEFS ENSEMBLES POINT TO THIS POTENTIAL.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...HIGH WIND WARNING UNTIL 4 PM EST THURSDAY FOR NYZ001>008-010-
011-019-020-085.
LAKE EFFECT SNOW ADVISORY FROM 10 AM THURSDAY TO 6 PM EST
FRIDAY FOR NYZ012-085.
LAKE EFFECT SNOW ADVISORY FROM 10 AM THURSDAY TO 1 AM EST
FRIDAY FOR NYZ007.
FLOOD WATCH THROUGH THURSDAY AFTERNOON FOR NYZ004>008-014.
LAKE EFFECT SNOW WARNING FROM 10 AM THURSDAY TO 6 PM EST
FRIDAY FOR NYZ006-008-019-020.
LAKE EFFECT SNOW WATCH FROM THURSDAY EVENING THROUGH FRIDAY
AFTERNOON FOR NYZ004-005.
WIND ADVISORY UNTIL 4 PM EST THURSDAY FOR NYZ012>014-021.
MARINE...GALE WARNING UNTIL 4 PM EST THURSDAY FOR LEZ040-041.
GALE WARNING UNTIL 10 AM EST THURSDAY FOR LEZ020.
SMALL CRAFT ADVISORY UNTIL 4 PM EST THURSDAY FOR
LOZ030.
GALE WARNING UNTIL 4 PM EST THURSDAY FOR LOZ042>045-
062>065.
&&
$$
SYNOPSIS...THOMAS
NEAR TERM...APFFEL/THOMAS
SHORT TERM...TMA
LONG TERM...TMA
AVIATION...APFFEL
MARINE...APFFEL/THOMAS
HYDROLOGY...APFFEL
AREA FORECAST DISCUSSION
NWS BUFFALO NY
1112 PM EST WED JAN 30 2013
.SYNOPSIS...
RAIN...HEAVY AT TIMES WILL FALL ACROSS THE REGION TONIGHT AHEAD OF A
COLD FRONT THAT WILL SWEEP ACROSS THE REGION WHICH WILL SEND
TEMPERATURES BACK TO SEASONAL NORMALS. AS THE COLD AIR DEEPENS ON
THURSDAY...LAKE EFFECT SNOWS WILL SET UP IN THE TRADITIONAL
SNOWBELTS EAST AND SOUTHEAST OF THE LAKES...THEN WILL CONTINUE
THROUGH THE END OF THE WEEK.
&&
.NEAR TERM /THROUGH THURSDAY/...
LOW PRESSURE ACROSS LAKE HURON WILL LIFT NORTHEAST ACROSS SOUTHERN
ONTARIO OVERNIGHT. THIS WILL BRING A COLD FRONT ACROSS THE REGION
TONIGHT...FORECAST TO ENTER FAR WESTERN NEW YORK AROUND
MIDNIGHT...THEN SWEEP RAPIDLY TO THE EAST THROUGH THE EARLY
MORNING HOURS. THIS WILL CAUSE AN ABRUPT DROP IN TEMPERATURES...AND
KEY THE ONSET IN GUSTY WINDS. EXPECT WIND GUSTS WILL PUSH 50 MPH
IMMEDIATELY BEHIND THE FRONT...BEFORE THE STEADIER WINDS AHEAD OF
A SECONDARY SHOT OF COLDER AIR.
IN ADDITION....THIS SYSTEM WILL SET UP A DEEP SOUTHERLY FLOW OUT
AHEAD OF IT...WHICH WILL TRANSPORT MOISTURE FROM PENNSYLVANIA AND
INTO CENTRAL NEW YORK TONIGHT. A BLEND OF RADAR AND HRRR MODEL
GUIDANCE THROUGH 1100 PM SUGGEST THE HEAVIEST RAINS WILL SLIDE A
BIT FURTHER EAST...MAINLY IMPACTING LOCATIONS EAST OF LAKE
ONTARIO. BECAUSE OF THIS...HAVE MODIFIED THE FLOOD WATCH. REFER TO
THE HYDROLOGY SECTION FOR MORE ON THIS.
THE SYSTEM WILL CAUSE MULTIPLE ISSUES FOR THE CWA...ORGANIZED BY
IMPACT BELOW.
1. STRONG WINDS...THE AFOREMENTIONED STORM SYSTEM WILL DEEPEN FROM
AROUND 985MB 00Z TONIGHT TO 970MB 12Z TOMORROW MORNING JUST NORTH OF
VERMONT...AND THEN BELOW 960 MB BY 00Z FRIDAY ACROSS EASTERN QUEBEC.
THIS RAPID DEEPENING...COMBINED WITH 6 TO 8 MB ISALLOBARIC PRESSURE
RISES WITHIN COLD AIR ADVECTION FOLLOWING THE COLD FRONT SHOULD BE
ABLE TO MIX A 50 KNOT JET AT 925 HPA DOWN TO THE SURFACE. GIVEN THE
STRONG AND VERY DYNAMIC NATURE OF THIS SYSTEM...ITS ASSOCIATED WIND
FIELDS WILL ALSO BE QUITE STRONG. WE WILL UPGRADE THE ADVISORY TO A
WARNING FOR A GOOD PORTION OF THE CWA. WIND GUSTS UP TO 60 MPH ARE
LIKELY IN FAVORED AREAS ALONG THE LAKE ERIE SHORELINE INLAND ACROSS
SOUTHERN LAKE ONTARIO AND THROUGH THE EASTERN LAKE ONTARIO REGION.
FOR OUR INLAND COUNTIES OF WYOMING...ALLEGANY...LIVINGSTON AND
ONTARIO WE WILL LEAVE A HIGH END WIND ADVISORY AS THE DEEPENING LOW
MAY BE TOO FAR NORTH TO ALLOW FOR WARNING CRITERIA WINDS HERE.
2. LAKE EFFECT SNOW...FOLLOWING THE PASSAGE OF THE COLD FRONT -14C
TO -16C 850 HPA AIR TEMPERATURES WILL BE CROSSING THE LAKES. AT
FIRST WINDS MAY BE TO STRONG FOR GOOD FORMATION OF LAKE EFFECT SNOW
BANDS WITH THE WINDS SHEARING AWAY THE LAKE BAND FORMATION. ALSO
WITH THE STRONG WINDS RESIDENT TIME OVER THE LAKE BODIES WILL BE
LIMITED. AS WINDS DIMINISH THROUGH THE AFTERNOON AND COLD AIR
DEEPENS...AND LAKE INDUCED EQUILIBRIUM LEVELS RISE TOWARDS 7 TO 9K
FEET A BAND OF SNOW SHOULD BE FORMING OFF BOTH LAKE ERIE AND LAKE
ONTARIO. THE NAM...AND TO A DEGREE THE GFS HAS DEEP SYNOPTIC
MOISTURE REMAINING IN THE SNOW GROWTH ZONE...WHICH WILL BE FALLING
WITH THE COLD AIR ADVECTION.
OFF LAKE ONTARIO...WIND FIELD CONVERGENCE OVER LAKE ONTARIO IS
LEADING TO IMPRESSIVE OMEGA FIELDS BY THURSDAY AFTERNOON WHERE A
BAND OF LAKE EFFECT SNOW MAY BEGIN TO PRODUCE SNOWFALL RATES UP TO 2
INCHES PER HOUR. FOLLOWING THE SURFACE LOW AND UPPER LEVEL TROUGH
WINDS WILL BEGIN TO VEER THROUGH THE DAY DROPPING THE LAKE EFFECT
SNOW BAND SOUTH OF JEFFERSON COUNTY. FOR THIS REASON WILL LEAVE
JEFFERSON COUNTY AS A HIGH END LAKE EFFECT SNOW ADVISORY...AND HAVE
WARNINGS FOR LEWIS AND OSWEGO COUNTIES WHERE THE BAND WILL LIKELY
FALL LONGER.
OFF LAKE ERIE...A WESTERLY FLOW OVER THE STILL OPEN WATERS OF LAKE
ERIE WILL BRING MULTI BANDED STRUCTURE SNOW BANDS ACROSS THE SOUTHERN
TIER. CONFIDENCE IS GREATER ACROSS CHAUTAUQUA AND CATTARAUGUS COUNTIES
THAN SOUTHERN ERIE AND WYOMING COUNTIES FOR WARNING CRITERIA SNOW.
WILL UPGRADE THE WATCH TO A LAKE EFFECT WARNING ACROSS THE SOUTHERN
TIER...WHILE LEAVING ADVISORIES FOR SOUTHERN TIER AND WYOMING
COUNTIES.
3. REGARDING TEMPERATURES...RECORDED HIGHS WERE SHATTERED ACROSS
MUCH OF THE REGION TODAY WITH MORNING AND EARLY AFTERNOON HIGHS
REACHING NEAR 10 DEGREES ABOVE RECORD VALUES FOR THE DATE.
THE NEW RECORDS FOR TODAY...
BUFFALO.....66 (PREVIOUS WAS 56 IN 1916)
ROCHESTER...64 (PREVIOUS WAS 55 IN 1974)
WATERTOWN...63 (PREVIOUS WAS 52 IN 1995)
THESE READINGS ARE STILL SEVERAL DEGREES SHY OF THE ALLTIME
MONTHLY RECORD HIGH TEMPERATURE WHICH ARE AS FOLLOWS:
BUFFALO.....72 IN 1950.
ROCHESTER...74 IN 1950...CORRECTED
WATERTOWN...66 IN 1995.
THE COLD FRONT WILL SWEEP ACROSS THE REGION TONIGHT SENDING
TEMPERATURES BACK TO SEASONAL NORMS...WITH MANY AREAS DOWN INTO THE
UPPER 20S AND LOW 30S BY TOMORROW MORNING. WITH THE RAIN OVERNIGHT
THE PROSPECTS FOR BLACK ICE WILL BE PRESENT AS WE QUICKLY COOL
FURTHER INTO THE MID AND UPPER 20S BY MID MORNING.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
HEAVY LAKE EFFECT SNOWS SHOULD BE ONGOING ON A WESTERLY FLOW
REGIME AT THE START OF THE PERIOD. BUFR PROFILES FROM THURSDAY
NIGHT THROUGH AT LEAST THE DAYTIME HOURS OF FRIDAY CONTINUE TO
LOOK RATHER IMPRESSIVE...AS A DEEP LAYERED CYCLONIC FLOW REGIME IS
WELL ESTABLISHED. MOISTURE PROFILES LOOK QUITE ADEQUATE WITH
SATURATION WELL UP THROUGH 10K FEET AND DEEPER AT TIMES AS A
COUPLE OF REINFORCING WEAK SHORTWAVES WORK THROUGH THE MEAN WEST
NORTHWEST FLOW. THE BIGGEST FACTOR THAT COULD LIMIT TOTALS WILL BE
THE VEERING WINDS IN RESPONSE TO A SHORTWAVE CROSSING THE LOWER
LAKES. THIS WILL TEND TO PUSH THE LAKE BANDS...ESPECIALLY ACROSS
LAKE ONTARIO SOUTHWARD. THIS COULD BRING THE PRIME LAKE EFFECT
FOCUS ALONG THE SOUTH SHORE OF LAKE ONTARIO...WHICH COULD BRING AT
LEAST ADVISORY OR GREATER TOTALS TO THIS AREA INCLUDING THE
ROCHESTER METRO AREA. FEEL A BIT MORE CONFIDENT WITH THE AREA FROM
WAYNE OVER TO NORTHERN CAYUGA AT THIS POINT...THEREFORE WILL ISSUE
A LAKE EFFECT SNOW WATCH FOR THAT AREA...BUT IT IS HIGHLY POSSIBLE
THAT LAKE EFFECT HEADLINES MAY NEED TO BE ISSUED FARTHER TO THE
WEST.
ANOTHER SHORTWAVE APPROACHING THE REGION FRIDAY NIGHT AND SATURDAY
MAY REORIENT THE LAKES SNOWS FOR A TIME NORTHWARD AS THE FLOW
BACKS TO WEST SOUTHWEST...POTENTIALLY BRINGING SOME ACCUMULATING
SNOWS INTO PORTIONS OF THE BUFFALO METRO AND WATERTOWN AREAS. THE
PASSAGE OF THE SHORTWAVE SHOULD RE-ESTABLISH THE LAKE SNOWS BACK
SOUTHWARD LATER SATURDAY AND SATURDAY NIGHT.
MUCH COLDER AIR MASS ACROSS THE AREA FRIDAY AND SATURDAY WITH
DAYTIME HIGHS IN THE TEENS AND 20S...WITH WIND CHILLS PERIODICALLY
BELOW ZERO.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
THE VERY COLD AIR REMAINS IN PLACE SUNDAY...BEFORE A GRADUAL
MODIFICATION OF THE AIR MASS OCCURS INTO EARLY NEXT WEEK AS THE
UPPER TROUGH SHIFTS TO THE EAST. TWO CLIPPER TYPE WAVES LOOK TO
IMPACT THE LOWER LAKES REGION DURING THIS TIME FRAME. ONE WAVE MOVES
THROUGH ON SUNDAY WHICH MAY SERVE TO ENHANCE THE ONGOING LAKE EFFECT
SNOWS IN A WESTERLY FLOW REGIME. THE SECOND WAVE LOOKS TO MOVE
THROUGH LATE MONDAY OR EARLY TUESDAY AND APPEARS TO BE RATHER ROBUST
AND GIVEN THE PROJECTED TRACK OF THE ASSOCIATED SURFACE LOW COULD
BRING THE POTENTIAL FOR A GENERAL WIDESPREAD SEVERAL INCHES OF SNOW.
BEHIND THIS WAKE A COLDER FLOW DEVELOPS WHICH MAY REDEVELOP SOME
LAKE SNOWS BUT LACK OF SIGNIFICANT MOISTURE COULD LIMIT SNOWFALL
POTENTIAL.
&&
.AVIATION /04Z THURSDAY THROUGH MONDAY/...
A BROAD AREA OF SHOWERS WILL MOVE INTO THE REGION...BOTH
STREAMING FROM THE SOUTH AND AHEAD OF A COLD FRONT. THIS WILL
BRING A PERIOD OF RAIN TO ALL TAF SITES...BUT WITH THE SOUTHERLY
DOWNSLOPE COMPONENT TO THE FLOW CIGS WILL BE INITIALLY SLOW TO
DROP.
AS THE COLD FRONT CROSS THE AREA BETWEEN 04Z AND 09Z...CIGS WILL
DROP AND IFR CONDITIONS WILL BECOME MORE WIDESPREAD...ESPECIALLY
DOWNWIND OF THE LAKES. RAIN WILL MIX WITH...THEN CHANGE TO SNOW
BEFORE DAYBREAK THURSDAY.
STRONG COLD AIR ADVECTION BEHIND THE DEPARTING FRONT WILL INCREASE
MIXING AND RAPIDLY STRENGTHEN WESTERLY WINDS OVERNIGHT. LATE TONIGHT
INTO THURSDAY MORNING...EXPECT WINDS TO GUST TO 40-50 KNOTS IN MOST
LOCATIONS...BEFORE TAPERING OFF LATE THURSDAY AFTERNOON. LAKE
SNOWS WILL DEVELOP EAST OF THE LAKES. THESE WILL LIKELY STAY OUT
OF BUF/IAG/ROC...BUT SHOULD IMPACT ART/JHW FOR A PERIOD.
CONDITIONS WILL VARY SIGNIFICANTLY IN AND OUT OF LAKE EFFECT BANDS.
OUTLOOK...
THURSDAY NIGHT THROUGH SATURDAY...MVFR WITH LOCALIZED IFR IN LAKE
EFFECT SNOW EAST OF THE LAKES.
SUNDAY...MAINLY VFR WITH MVFR IN LOCALIZED LAKE EFFECT SNOW SHOWERS.
MONDAY...VFR.
&&
.MARINE...
A COMPLEX AREA OF LOW PRESSURE FROM SOUTHERN CANADA AND THROUGH THE
CENTRAL GREAT LAKES REGION THIS AFTERNOON WILL LIFT NORTHEASTWARD
AND DEEPEN TONIGHT AND TOMORROW. A COLD FRONT SWINGING ACROSS THE
LAKES...COUPLED WITH STRONG COLD AIR ADVECTION AND RAPID DEEPENING
OF THE SURFACE LOW WILL INCREASE WINDS QUICKLY TO GALE FORCE
FOLLOWING THE PASSAGE OF THE FRONT TONIGHT...WITH GALES THEN
CONTINUING THROUGH MUCH OF THURSDAY. FOR THIS REASON...GALE WARNINGS
WILL CONTINUE AS OUTLINED ON THE LAKES. WINDS AND WAVES WILL STILL
REMAIN STRONG THURSDAY EVENING THROUGH SATURDAY...BEFORE DIMINISHING
TO BELOW SMALL CRAFT CONDITIONS BY SATURDAY NIGHT.
&&
.HYDROLOGY...
FOLLOWING A BLEND OF RADAR AND NEAR TERM GUIDANCE...IT APPEARS THE
STEADIEST RAINS WILL FALL EAST OF LAKE ONTARIO...WITH LESSER
AMOUNTS WEST OF THE GENESEE RIVER. EAST OF LAKE ONTARIO...EXPECT
AROUND AN INCH OF RAIN TO FALL...WITH LESS THAN THAT WEST OF THE
GENESEE. LATEST RFC FORECASTS HAVE LOWERED CRESTS AT
WELLSVILLE...WITH THE MAJORITY OF MMEFS GUIDANCE KEEPING THE
BUFFALO CREEKS...GENESEE RIVER...AND ALLEGHENY RIVER BELOW FLOOD
STAGE. THERE STILL MAY BE A FEW LINGERING ICE JAMS IN TYPICALLY
FLOOD PRONE AREAS IN PARTS OF CHAUTAUQUA COUNTY.
THERE STILL A THREAT FOR FLOODING IN EASTERN PORTIONS...WHERE AN
INCH OF RAINFALL STILL APPEARS LIKELY. LOCALLY HIGHER AMOUNTS FROM
CONVECTION AND/OR UPSLOPING MAY ALSO OCCUR. THIS COMBINED WITH
SNOW MELT FROM LOCATIONS EAST OF LAKE ONTARIO WILL RESULT IN
SIGNIFICANT RISES IN THE RIVERS AND CREEKS. AN INCH OF RAIN IS
STILL MARGINAL TO CAUSE FLOODING...BUT WITH SNOW MELT QUITE
DIFFICULT TO FORECAST...AND SOME ICE JAMS POSSIBLE...THERE IS A
CONTINUED RISK OF FLOODING. THE SREF AND TO A LESSER EXTENT GFS/GGEM
BASED MMEFS ENSEMBLES POINT TO THIS POTENTIAL.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...HIGH WIND WARNING UNTIL 4 PM EST THURSDAY FOR NYZ001>008-010-
011-019-020-085.
LAKE EFFECT SNOW ADVISORY FROM 10 AM THURSDAY TO 6 PM EST
FRIDAY FOR NYZ012-085.
LAKE EFFECT SNOW ADVISORY FROM 10 AM THURSDAY TO 1 AM EST
FRIDAY FOR NYZ007.
FLOOD WATCH THROUGH THURSDAY AFTERNOON FOR NYZ004>008-014.
LAKE EFFECT SNOW WARNING FROM 10 AM THURSDAY TO 6 PM EST
FRIDAY FOR NYZ006-008-019-020.
LAKE EFFECT SNOW WATCH FROM THURSDAY EVENING THROUGH FRIDAY
AFTERNOON FOR NYZ004-005.
WIND ADVISORY UNTIL 4 PM EST THURSDAY FOR NYZ012>014-021.
MARINE...GALE WARNING UNTIL 4 PM EST THURSDAY FOR LEZ040-041.
GALE WARNING UNTIL 10 AM EST THURSDAY FOR LEZ020.
SMALL CRAFT ADVISORY UNTIL 4 PM EST THURSDAY FOR
LOZ030.
GALE WARNING UNTIL 4 PM EST THURSDAY FOR LOZ042>045-
062>065.
&&
$$
SYNOPSIS...THOMAS
NEAR TERM...APFFEL/THOMAS
SHORT TERM...TMA
LONG TERM...TMA
AVIATION...APFFEL
MARINE...APFFEL/THOMAS
HYDROLOGY...APFFEL
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
204 AM MST THU JAN 31 2013
.UPDATE...
ISSUED AT 201 AM MST THU JAN 31 2013
AS OF 2 AM...RADAR AND WEBCAMS CONTINUE TO SHOW SNOW BANDS
PERSISTING OVER GLENWOOD SPRINGS AND THROUGH GLENWOOD CANYON.
LATEST HRRR AND RAP SHOW SNOW CONTINUING THROUGH 15Z WITH SNOW
RAPIDLY DROPPING OFF AFTERWARDS. THIS CORRESPONDS WELL WITH TIME
HEIGHTS OVER GLENWOOD CANYON SHOWING DEEP SATURATED LAYER IN THE
DENDRITIC GROWTH ZONE WITH DECENT UPWARD MOTION PERSISTING THROUGH
15Z BEFORE THE PROFILE DRIES OUT. THEREFORE...EXTENDED THE WINTER
WEATHER ADVISORY FOR COZ008 THROUGH 15Z THIS MORNING.
UPDATE ISSUED AT 1130 PM MST WED JAN 30 2013
BASED ON RADAR AND SATELLITE OBSERVATIONS...THE PERSISTENT SNOW
BANDS THAT BROUGHT SNOW TO THE I-70 CORRIDOR HAVE SHIFTED EASTWARD
WITH CONDITIONS IMPROVING FROM RIFLE TO SILT BASED ON OBSERVATIONS
AND WEBCAMS. THIS IS CONSISTENT WITH THE LATEST RAP DATA SHOWING
LITTLE IF ANY ADDITIONAL ACCUMULATIONS HERE. THEREFORE CANCELLED
THE WINTER WEATHER ADVISORY FOR COZ007. WEBCAMS AND RADAR STILL
SHOW SNOW BANDS STREAMING ACROSS THE FLATTOPS...THE I-70 CORRIDOR
FROM GLENWOOD SPRINGS TO VAIL PASS...AND STEAMBOAT. REMAINING
HIGHLITES LOOK ON TRACK.
UPDATE ISSUED AT 536 PM MST WED JAN 30 2013
PERSISTENT SNOW OVER THE I-70 CORRIDOR WEST OF EAGLE AND EAST OF
PALISADE HAD ALREADY BROUGHT 1 TO 2 INCHES OF SNOW TO THESE AREAS
EARLY THIS EVENING. LATEST NAM12 AND RAP13 DATA INDICATED THIS
PERSISTENT BAND OF SNOW COULD LAST THROUGH THE EVENING BRINGING
FROM 2 TO 5 INCHES OF BY EARLY MORNING. THEREFORE...A WINTER
WEATHER ADVISORY HAS BEEN ISSUED ZONES 7 AND 8. AREAS IN ZONE 8
ARE NOT INCLUDED IN THIS ADVISORY.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 302 PM MST WED JAN 30 2013
SNOW AND WIND IMPACTING THE NERN PART OF THE FORECAST AREA TODAY.
CLASSIC OROGRAPHIC SNOW IN NORTHWEST FLOW AS PACIFIC MOISTURE
AND STRONG JET TARGETS THE PARK/GORE RANGES AND THE FLAT TOP
MOUNTAINS. MT WERNER SENSORS SHOW WIND OF 25 MPH BUT GUSTS TO
AROUND 40 MPH. GIVEN LOW SNOW TO LIQUID RATIO VALUES...WEB CAMS SHOWING
POOR VISIBILITY OVER THE MOUNTAIN PASSES. SNOTEL SITES SHOWING 6
HOUR QPF GENERALLY RANGING FROM /0.20/ TO /0.50/ INCHES...BUT THIS
MAY EQUATE TO 5 TO 13 INCHES OF SNOW IF LIQUID TO WATER RATIO IS
AROUND 25:1 OR HIGHER. THE HEAVIEST SNOW APPEARS CONFINED ABOVE
8500 FEET...OBSERVATIONS FROM THE PUBLIC AND SPOTTER REPORTS
SUGGEST ONLY LIGHT SNOW IN THE MOUNTAIN VALLEYS (FROM MARBLE AND
ASPEN).
MODEL DATA KEEPS MOISTURE STREAM AND OROGRAPHIC SNOW ONGOING
THROUGH THE NIGHT...BUT GRADUALLY TAPERS OFF ON THURSDAY. GRADIENT FLOW
DOES WEAKEN ON THURSDAY WITH MOISTURE STREAM SOMEWHAT WEAKER...THEREFORE
EXPECT SNOWFALL RATES TO DIMINISH ON THURSDAY. NO CHANGES TO THE
CURRENT WINTER STORM WARNINGS AS ACCUMULATING SNOWFALL COMBINED
WITH WIND WILL PERSIST INTO THURSDAY. IN ADDITION...AN EMBEDDED
DISTURBANCE IN NORTHWEST FLOW RACES ACROSS THE NRN DIVIDE MOUNTAINS
LATE THURSDAY AFTERNOON. ONCE THIS SHORT WAVE CROSSES THE
DIVIDE...EXPECT SNOW AND WIND TO TAPER OFF CONSIDERABLY.
FOR THE REMAINDER OF THE FORECAST AREA...MUCH OF EASTERN UTAH AND
EXTREME WRN COLORADO WILL BE DRY. EXTENSIVE CLOUD COVER THAT
COVERS MUCH OF THE REGION TODAY WILL GRADUALLY ERODE AWAY. MORE
SUN EXPECTED ON THURSDAY ACROSS THE SWRN HALF OF THE FORECAST
AREA. WITH LESS CLOUD COVER... EXPECT OVERNIGHT TEMPS ON FRIDAY
MORNING TO BE THE COLDEST OF THE WEEK FOR THE NRN AND CENTRAL
VALLEYS.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 302 PM MST WED JAN 30 2013
A WAVE IN NW FLOW WILL CLIP NW CO FRI AS IT MOVES INTO THE PLAINS.
THE GFS/ECMWF/CANADIAN MODELS IN GENERAL AGREEMENT HERE AND HAVE
BOOSTED POPS FOR THE ELKHEAD AND PARK RANGES BASED ON THIS. A PERIOD
OF Q-FORCING ALOFT WITH WARM ADVECTIVE UPLIFT AT MTN TOP LEVEL AND
WITH W-NW OROGRAPHICS SHOULD RESULT IN SOME AREAS OF SNOW FROM ABOUT
MIDDAY FRI INTO FRI EVENING.
THIS WEEKEND LOOKS DRY AS THE WEST COAST RIDGE SLIDES OVER THE
FORECAST AREA. A SMALL CLOSED LOW CURRENTLY DEVELOPING OFF THE CA
COAST IS FORECAST TO SHEAR INLAND AND WEAKEN WHILE A LARGER PACIFIC
TROUGH SPLITS AS IT APPROACHES THE COAST. THIS MORNING/S MODELS WERE
IN GENERAL AGREEMENT WITH TAKING THE SOUTHERN PORTION OF THE SPLIT
AND FORMING A CUT-OFF LOW WELL OFF THE CA COAST...WHILE THE NORTHERN
SPLIT BRUSHES OUR FORECAST ABOUT SUNDAY. NEITHER THE GFS NOR ECMWF
SHOW MUCH CHANCE OF SIGNIFICANT PRECIPITATION THOUGH FROM THE
NORTHERN WAVE THOUGH.
GFS HAS BEEN INCONSISTENT HANDLING THE SOUTHERN SPLIT CUT-OFF
LOW...ALTERNATING BETWEEN BRINGING TO ABOUT THE 4 CORNERS BY TUE AND
KEEPING IT OFFSHORE INLINE WITH THE MORE CONSISTENT ECMWF. FOLLOWING
MORE THE PREFERRED ECMWF WOULD RESULT IN GENERAL RIDGING OVER ERN
UT/WRN CO EARLY NEXT WEEK AND A MINIMAL CHANCE OF PRECIP. BUT BOTH
THE GFS AND ECMWF SHOW A DECENT TROUGH APPROACHING THE PACIFIC NW
COASTLINE ON WEDNESDAY...FOR POTENTIALLY UNSETTLED WEATHER LATE NEXT
WEEK.
TEMPERATURES ARE EXPECTED TO GRADUALLY MODERATE THIS PERIOD ALTHOUGH
TEMPS WILL STILL BE A BIT OF A CHALLENGE IN MANY VALLEYS. SNOW
COVER WILL KEEP TEMPS IN THE EASTERN UINTA BASIN LAGGING THE MOST
BEHIND...HOWEVER...WHERE AN INVERSION SHOULD BE SLOW TO ERODE. INVERSIONS
WILL NOT BE A STRONG FOR THE GRAND VALLEY WHERE SNOW COVER IS
DIMINISHING IN AREAL EXTENT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1015 PM MST WED JAN 30 2013
A PERSISTENT MOIST NORTHWEST FLOW WILL CONTINUE TO DELIVER SNOW TO
THE NORTHERN AND CENTRAL MOUNTAINS AND ADJACENT VALLEYS DURING THE
REMAINDER OF THE NIGHT. AS A RESULT...EXPECT KSBS AND KASE TO HAVE
PERSISTENT MVFR CIGS AND VSBY WITH OCCASIONAL IFR CONDITIONS DURING
MUCH OF THE REMAINDER OF THE NIGHT WITH SURROUNDING MOUNTAINS
OBSCURED IN SNOW. KRIL...KGWS...AND KGUC WILL HAVE OCCASIONAL
MVFR CIGS AND VSBY IN SNOW SHOWERS THROUGH 12Z THURSDAY.
MODELS CONTINUE TO GENERATE MOUNTAIN SNOW OVER THE NORTHERN AND
CENTRAL MOUNTAINS THURSDAY THROUGH MIDNIGHT...THOUGH LIGHTER IN
INTENSITY AND LESS EXTENSIVE. ADJACENT TERMINALS ARE UNLIKELY TO
DROP BELOW VFR CONDITIONS THURSDAY.
AREAS WEST OF A KPSO TO KCAG LINE WILL HAVE VFR CONDITIONS THROUGH
THE NEXT 24 HOURS.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...WINTER WEATHER ADVISORY UNTIL 8 AM MST THIS MORNING FOR COZ008.
WINTER STORM WARNING UNTIL 6 PM MST THIS EVENING FOR COZ004-005-
010-013.
UT...NONE.
&&
$$
UPDATE...MDA
SHORT TERM...PF
LONG TERM...JAD
AVIATION...NL
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
1006 AM EST Thu Jan 31 2013
...Possible short duration light freeze tonight...
...Another freeze possible Friday night...
.NEAR TERM [Through Tonight]...
Updated at 945 am EST-
The 12 UTC regional surface analysis showed the cold front that
moved through our forecast area last night was over South FL,
while a 1024 mb high pressure ridge (centered over LA) was
building east along the Gulf Coast. Vapor imagery and upper air
data showed a broad trough over much of the eastern CONUS, with
plenty of dry air throughout the atmospheric column. Based on our
12 UTC KTAE sounding and the latest NWP guidance, we expect high
temperatures today will be in the mid to upper 50s.
With the ridge building in quickly, surface winds will likely
become calm shortly after sunset. This will allow for rapid
cooling, and a light freeze is possible at our normally coldest
sites (inland, relatively "open" areas away from cities). Even for
those areas that don`t quite reach freezing, frost will be
possible. The one limiting factor (which could prevent a deeper
freeze) will be the potential for surface winds to increase
slightly shortly before dawn, ahead of a dry cold front just to
the north.
&&
.SHORT TERM [Friday Through Saturday]...
High Temps both Friday and Saturday will be slightly below
climatology and generally range from the upper 50s NW to the mid
60s SE. On Friday night, however, we could see one of the coldest
nights of the entire Winter Season thus far, as the Sfc Ridge
behind the Dry Cold Front will be positioned right overhead of the
CWA. This will allow for nearly ideal conditions for Radiational
Cooling with clear skies and near calm winds. Low Temps could
bottom out in the middle 20s over much of the interior, which will
result in at least a long duration light freeze, and the
possibility of the first Hard Freeze of the season. Therefore, all
outdoor interests and those with sensitive vegetation should keep
abreast of the latest information from the National Weather
Service in Tallahassee.
&&
.Long Term [Sunday night through Thursday]...
Undated at 945 am EST-
Mostly zonal flow will dominate on the southern periphery of
broad eastern U.S. troughing through the period. A weak impulse
will pass overhead late on Monday, however, dry air will limit the
impacts to passing high clouds with no chance for rain. A slightly
stronger mid/upper wave will approach towards the end of the
period. At this time, little to no rain is expected with this
disturbance either. Overall, the period will be dominated by dry
conditions and near or slightly above average temperatures.
&&
.AVIATION [through 18 UTC Friday]...
Undated at 945 am EST-
Unlimited visibility and ceilings will prevail through the period.
Winds will be NW 5 to 10 KT this afternoon, light overnight, then
NW 5 to 10 KT again Friday. The only possible visibility
restriction could be caused by any large fire occurring near a
terminal, but currently we don`t see any "hot spots" on
satellite/radar imagery that would concern us.
&&
.MARINE...
Updated at 945 am EST-
Winds & seas were still solidly at advisory levels, but the latest
NWP guidance (including high resolution RAP and local 4km WRF) is
unanimous in having the winds fall below advisory criteria by
early afternoon. Thereafter, light to moderate offshore winds and
seas will dominate through Friday, with a period of cautionary
northeasterly winds expected on Friday night. Then, light winds
and low seas are anticipated for the upcoming weekend and
beginning of next week.
&&
.FIRE WEATHER...
Very dry conditions will overspread the region today and continue
into the weekend. Red flag conditions look like a near certainty
across much of North Florida today and possibly again on Friday.
Though RH values will be below 25 percent in Alabama and Georgia
today and on Friday, it appears as though the other required
criteria (winds and/or fuel moisture) will not be met. More moist
conditions will return by Sunday, putting an end to any red flag
concerns.
&&
.HYDROLOGY...
Despite a fairly widespread rainfall across the region on Wednesday
(with most areas receiving between 0.50" and 2" of rain, with the
highest amounts well to the N and W), only minor rises have been
observed on area rivers thus far. The only exception appears to be
the Choctawhatchee River, where the river may rise to near action
stage at Caryville during the next few days.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 58 32 63 25 63 / 0 0 0 0 0
Panama City 57 42 61 36 61 / 0 0 0 0 0
Dothan 56 36 57 28 60 / 0 0 0 0 0
Albany 56 32 57 26 60 / 0 0 0 0 0
Valdosta 57 32 61 25 62 / 0 0 0 0 0
Cross City 60 30 66 26 65 / 0 0 0 0 0
Apalachicola 57 40 62 35 59 / 0 0 0 0 0
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...FREEZE WATCH from late tonight through Friday morning for
Calhoun-Central Walton-Coastal Dixie-Coastal Taylor-
Gadsden-Holmes-Inland Bay-Inland Dixie-Inland Franklin-
Inland Gulf-Inland Jefferson-Inland Taylor-Inland Wakulla-
Inland Walton-Jackson-Lafayette-Leon-Liberty-Madison-
Washington.
RED FLAG WARNING until 7 PM EST /6 PM CST/ this evening for
Calhoun-Central Walton-Coastal Bay-Coastal Dixie-Coastal
Jefferson-Coastal Taylor-Coastal Wakulla-Gadsden-Holmes-
Inland Bay-Inland Dixie-Inland Jefferson-Inland Taylor-
Inland Wakulla-Inland Walton-Jackson-Lafayette-Leon-
Liberty-Madison-South Walton-Washington.
FIRE WEATHER WATCH from Friday afternoon through Friday
evening for Calhoun-Central Walton-Coastal Bay-Coastal
Dixie-Coastal Franklin-Coastal Gulf-Coastal Jefferson-
Coastal Taylor-Coastal Wakulla-Gadsden-Holmes-Inland Bay-
Inland Dixie-Inland Franklin-Inland Gulf-Inland Jefferson-
Inland Taylor-Inland Wakulla-Inland Walton-Jackson-
Lafayette-Leon-Liberty-Madison-South Walton-Washington.
GA...FREEZE WATCH from late tonight through Friday morning for
Baker-Ben Hill-Berrien-Brooks-Calhoun-Clay-Colquitt-Cook-
Decatur-Dougherty-Early-Grady-Irwin-Lanier-Lee-Lowndes-
Miller-Mitchell-Quitman-Randolph-Seminole-Terrell-Thomas-
Tift-Turner-Worth.
AL...FREEZE WATCH from late tonight through Friday morning for
Coffee-Dale-Geneva-Henry-Houston.
GM...SMALL CRAFT ADVISORY until 1 PM EST this afternoon for
Apalachee Bay or Coastal Waters From Keaton Beach to
Ochlockonee River Fl out to 20 Nm-Coastal Waters From
Ochlockonee River to Apalachicola Fl out to 20 Nm-Coastal
waters from Suwannee River to Keaton Beach out 20 NM-
Coastal waters from Apalachicola to Destin FL out 20 NM-
Waters from Suwannee River to Apalachicola FL from 20 to
60 NM-Waters from Apalachicola to Destin FL from 20 to 60
NM.
&&
$$
NEAR TERM...Fournier
SHORT TERM...Gould
LONG TERM...Harrigan
AVIATION...Fournier
MARINE...Fournier/Gould
FIRE WEATHER...Fournier/Gould
HYDROLOGY...Gould
AREA FORECAST DISCUSSION
NWS GOODLAND KS
448 AM MST THU JAN 31 2013
.SHORT TERM...(TODAY THROUGH SATURDAY NIGHT)
ISSUED AT 412 AM MST THU JAN 31 2013
FORECAST PROBLEMS WILL PROBLEMATIC TEMPERATURE FORECAST INTO TONIGHT
AND HOW MUCH TO WARM UP THE HIGH TEMPERATURES INTO SATURDAY.
SATELLITE SHOWING A BROAD UPPER TROUGH OVER THE TROUGH OVER THE
WESTERN AND CENTRAL PACIFIC WITH A RIDGE ALONG THE WEST COAST OF
NORTH AMERICA. A COUPLE OF SYSTEMS COMING INTO THE RIDGE ARE BEATING
IT DOWN. A STRONG AND COLD SYSTEM IS DIGGING INTO THE NORTH CENTRAL
PORTION OF THE COUNTRY. VERY COLD AIR MASS HAS MOVED FURTHER SOUTH
FROM YESTERDAY AND IS NOT TOO FAR NORTH AND EAST OF OUR AREA.
MODELS INITIALIZED WELL AT JET LEVEL WITH THE CANADIAN...GFS...AND
NAM DOING THE BEST. MODELS INITIALIZED WELL AT MID LEVELS WITH THE
GFS...CANADIAN...AND NAM DOING SLIGHTLY BETTER. LARGER SCALE MODELS
DO NOT HAVE THE BACKDOOR COLD FRONT FAR ENOUGH SOUTH AND WEST BY
06Z...OH SURPRISE. THE RUC HAS CONTINUED TO GET BETTER AS THE
NIGHT HAS PROGRESSED. OUTSIDE OF THE RUC ON THE LOW LEVEL THERMAL
FIELD...THE ECMWF AND GFS WERE DOING A LITTLE BETTER THAN THE UKMET
AND NAM.
TODAY/TONIGHT...VERY THICK CLOUD COVER HAS SPREAD OVER THE AREA
THROUGH THE NIGHT. WHAT THIS HAS DONE HAS PREVENTED ANY FALL OF THE
TEMPERATURES AND IN FACT HAS CAUSED THE TEMPERATURES TO RISE SOME.
NWP OUTPUT MUST BE UNDERDOING THIS CLOUD COVER AND IS TOO COOL WITH
TEMPERATURES. THIS CLOUD COVER IS BEING CAUSED BY STRONG MID TO
UPPER LEVEL JET. SOUNDINGS AND PLAN VIEW RELATIVE HUMIDITY PLOTS SHOW
THIS CLOUD COVER LASTING MOST OF THE DAY...ESPECIALLY IN THE
NORTHEAST PORTION.
BACKDOOR COLD FRONT WITH VERY COLD AIR BEHIND IT HAS BEEN MOVING
STEADILY TOWARD THE AREA THROUGH THE NIGHT AND IS NOT THAT FAR
AWAY. RUC IS CATCHING ONTO THIS AT THIS TIME. INITIALLY WAS GOING TO
CUT HIGH TEMPERATURES FROM GOING FORECAST BUT CLOUD COVER HAS
COMPLICATED THAT. SO WILL BE STARTING MUCH WARMER THAN WHAT MOST OF
THE MODELS SAY. FRONT SAGS ACROSS THE AREA THROUGH THE DAY WITH
SOME LOCATIONS IN THE NORTHEAST HALF TO TWO THIRDS REACHING THEIR
MAX BY 18Z. SO COMBINING REALITY AND THE RUC ADJUSTED MAX
TEMPERATURES UP BUT HAVE EXTREMELY LOW CONFIDENCE ABOUT THIS. DID
NOT GOES AS WARM AS IT BECAUSE OF THE CLOUD COVER. HRRR WOULD
INDICATE HIGH TEMPERATURES ABOUT 10 DEGREES WARMER IN THE SOUTHWEST
PORTION OF THE AREA THAT WHAT I HAVE.
LEFT FRONT QUADRANT OF INCOMING JET WILL CONTINUE TO AFFECT THE
NORTHEAST HALF TO TWO THIRDS OF THE AREA INTO EARLY AFTERNOON.
SEVERAL STATIONS HAVE REPORTED BRIEF PERIODS OF FLURRIES. ALL MODEL
OUTPUT AGREES IN PLACING LIGHT QPF IN THE ABOVE MENTIONED AREA. SREF
PROBABILITIES AGREE WITH THAT. IT MAKES SENSE WITH THE JET...
MESOSCALE FORCING AND LAPSE RATES IN PLACE. HOWEVER...DRIER AIR
IN THE LOWEST LAYERS. SO INTRODUCED SCATTERED FLURRIES THROUGH
MIDDAY WHEN THE FORCING AND MOISTURE LEAVE.
PROBLEMATIC MIN FORECAST AS WELL. WINDS SHIFT AROUND TO A SOUTH
DIRECTION PRETTY QUICKLY. NAM IS THE MOST AGGRESSIVE BUT IS
SUPPORTED BY OTHER MODEL OUTPUT IN BRINGING STRATUS AND FOG DURING
THE LATE EVENING AND OVERNIGHT HOURS. THIS IS AS THE COLD FRONT
RETREATS BACK AS A WARM FRONT AND ALL THE MODELS ARE VERY SIMILAR
IN DOING IT. MINS WILL PROBABLY BE REACHED IN THE EVENING
ESPECIALLY IN THE WEST AND POSSIBLY IN THE SOUTH AND A NON-DIURNAL
CURVE WILL HAVE TO BE INTRODUCED. BELIEVE MODELS ARE TOO COOL AND
WENT ABOVE THE GUIDANCE.
06Z NAM WAS MUCH MORE ROBUST IN BRINGING IN THE STRATUS AND FOG. NAM
HAS BEEN SHOWING THIS FOR A FEW DAYS PLUS THOSE SOUTH WINDS WILL BE
BLOWING ACROSS A SNOW FIELD. SO EXPANDED THE PATCHY FOG THAT WAS IN
THERE.
FRIDAY/FRIDAY NIGHT...STRATUS AND FOG GET PUSHED EAST PRETTY FAST BY
THE STRENGTHENING DOWNSLOPE WINDS. THERE MAY BE SOME HIGHER LEVEL
CLOUD COVER AROUND. INCOMING SHORTWAVE TROUGH IN NORTHWEST FLOW
ALOFT WILL PUSH A WEAK FRONT OR SURFACE TROUGH THROUGH LATER IN THE
DAY BUT IT LOOKS LIKE WINDS WILL BE FROM A DOWNSLOPE DIRECTION. SO
ENDED UP RAISING THE MAXES A LITTLE.
LEFT FRONT QUADRANT OF JET WILL AFFECT THE NORTHERN PORTION OF THE
AREA DURING THE NIGHT AS WELL AS THE ABOVE MENTIONED SHORTWAVE
TROUGH...WHICH HAPPENS TO BE THE ONE TOPPING THE RIDGE RIGHT NOW
NEAR WESTERN CANADA. ALL MODELS AGREE THAT THIS SYSTEM WILL HAVE
A VERY STRONG PV ANOMALY AS WELL. MODELS DO NOT SHOW A LOT OF
MOISTURE IN THE COLUMN BUT STRENGTH OF SYSTEM SHOULD COMPENSATE FOR
THAT. SO EXPANDED THE SPRINKLES AND FLURRIES OVER A LARGER AREA AND
THROUGH THE EVENING HOURS.
SATURDAY/SATURDAY NIGHT...RIDGING AND DRYING ALOFT PUSH INTO THE
AREA FOR SATURDAY. SO WILL HAVE PLENTY OF SUN ALONG WITH STRONG
DOWNSLOPE WINDS. SO RAISED MAXES MORE AND I MAY NOT BE WARM ENOUGH
AS I BELIEVE MODELS ARE TOO COOL.
.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 246 AM MST THU JAN 31 2013
MODEL AGREEMENT IS FAIRLY GOOD IN THE EXTENDED FORECAST. ALL
SOLUTIONS ARE POINTING TO A TAME WEATHER PATTERN WITHOUT ANY BIG
WEATHER CHANGES OR PRECIPITATION CHANCES. A SYSTEM WILL MOVE ACROSS
THE NORTHERN PLAINS AND GREAT LAKES ON MONDAY...BRINGING ONLY A WIND
SHIFT AND TEMPERATURES A DEGREE OR TWO COOLER. AFTER THAT...A RIDGE
OF HIGH PRESSURE BUILDS BACK IN FROM THE WEST.
TEMPERATURES SHOULD BE WELL ABOVE NORMAL FOR THIS TIME OF YEAR
THROUGHOUT THE EXTENDED FORECAST. HIGHS SHOULD BE IN THE 50S FOR
SUNDAY THROUGH TUESDAY...WITH HIGHS CLIMBING INTO THE 60S BY THE
MIDDLE OF NEXT WEEK. GUIDANCE HAS PULLED BACK SOMEWHAT FOR HIGH
TEMPERATURES ON SUNDAY BUT STILL THINK TEMPERATURES NEARING 60 FOR
EASTERN COLORADO IS NOT OUT OF THE QUESTION.
THE ONLY OTHER CONCERN FOR THE EXTENDED FORECAST WAS LOW
TEMPERATURES. THE INITIALIZATION PROCEDURE INPUT LOW TEMPERATURES
THAT WERE LIKELY TOO WARM. CONSIDERING THE ONGOING DROUGHT
CONDITIONS AND MEX AND ECE GUIDANCE SUGGESTING TEMPERATURES MUCH
LOWER THAN THE INITIALIZATION...HAVE LOWERED LOW TEMPERATURES A
DEGREE OR TWO. GUIDANCE IS ALTERED BY CLIMATOLOGICAL DATA SO THIS
COULD BE THE REASON MEX AND ECE GUIDANCE IS BEING HELD DOWN
SOMEWHAT. HOWEVER...THE HIGHER LOW TEMPS SEEMED A LITTLE
UNREASONABLE WITH CLEAR SKIES AND LIGHT WINDS THROUGHOUT THE
EXTENDED PERIOD.
THANKS TO ALL FOR THE COLLABORATION.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 444 AM MST THU JAN 31 2013
AT THE BEGINNING OF THE PERIOD...EVEN THOUGH VFR CONDITIONS WILL
EXIST...THE LOW AND MID LEVEL CLOUD DECK WILL BE QUITE THICK. SOME
FLURRIES WITH LITTLE TO NO VISIBILITY RESTRICTIONS WILL
OCCUR...MAINLY AT KGLD. BY LATE MORNING SOME CLEARING WILL OCCUR
NEAR KGLD. THE WIND WILL BECOME BRIEFY GUSTY BEFORE DECREASING AND
SHIFTING TO AN EASTERLY DIRECTION AS A BACKDOOR COLD FRONT PUSHES
ACROSS THE AREA. DURING THE NIGHT THE LOW LEVELS WILL BECOME MORE
MOIST AS SOUTH TO SOUTHEAST WINDS ADVECT THE MOISTURE IN. MVFR TO
NEAR IFR CONDITIONS WILL OCCUR WHEN THIS BEGINS. THESE CONDITIONS
WILL LAST LONGER AT KMCK THAN AT KGLD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...BULLER
LONG TERM...RRH
AVIATION...BULLER
AREA FORECAST DISCUSSION...UPDATED
NWS DODGE CITY KS
533 AM CST THU JAN 31 2013
...UPDATED FOR AVIATION...
.SYNOPSIS...
ISSUED AT 349 AM CST THU JAN 31 2013
THE 00Z UPPER AIR ANALYSES SHOWED ONE MAJOR SHORTWAVE TROUGH
MOVING EASTWARD ACROSS ILLINOIS AND MISSOURI WHILE ANOTHER
SHORTWAVE TROUGH WAS JUST UPSTREAM OVER NORTH DAKOTA PROGRESSING
SOUTHEASTWARD. A LEAD ARCTIC FRONT WITH THE 1ST SHORTWAVE TROUGH
HAD STALLED ACROSS WESTERN KANSAS AND SOUTHWESTERLY DOWNSLOPE
WINDS WERE ACTUALLY PUSHING THE FRONT BACK TO THE NORTHEAST AS A
WARM FRONT. IN FACT, TEMPERATURES AS OF 3 AM WERE IN THE LOWER 30S
AT PLACES LIKE MCCOOK AND OGALLALA, NE AND GOODLAND, WHICH IS
VERY BALMY FOR THIS TIME OF MORNING IN JANUARY. MID LEVEL CLOUD
WAS PROGRESSING SOUTHWARD INTO NORTHWESTERN KANSAS. THE NEXT
ARCTIC FRONT WAS SLOWLY EDGING SOUTHWARD INTO SOUTHERN SOUTH
DAKOTA AND TEMPERATURES WERE WELL BELOW ZERO BEHIND THIS FRONT.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 349 AM CST THU JAN 31 2013
AS THE 2ND SHORTWAVE TROUGH MOVES SOUTHEAST TODAY, THE ASSOCIATED
REINFORCING ARCTIC FRONT WILL PROGRESS SOUTHWARD INTO CENTRAL AND
NORTHERN KANSAS LATE THIS MORNING, AND THEN SOUTHWESTWARD IN BACK
DOOR FASHION INTO DODGE CITY AND PRATT BY THIS EVENING. THERE ARE
SEVERAL COMPLICATING FACTORS FOR HIGH TEMPERATURES TODAY, INCLUDING
PERSISTENCE OF SNOW COVER FROM GARDEN CITY TO DODGE CITY TO HAYS,
DOWNSLOPE WARMING AHEAD OF THE FRONT, FRONTAL TIMING, AND THE
AMOUNT OF MID LEVEL CLOUD COVER. TEMPERATURES WILL BE TRICKIEST
AROUND HAYS AND STAFFORD WHERE IT IS NOT CLEAR IF THE ARCTIC AIR
WILL ARRIVE BEFORE DAYTIME HEATING OCCURS. UPON COORDINATION, IT
WAS DECIDED TO GO WITH MID 30S AT HAYS FOR AN EARLY HIGH AROUND
18-19Z, WITH FALLING TEMPERATURES THEREAFTER. WARMER 40S TO NEAR
50 DEGREES SEEMS REASONABLE FURTHER SOUTHWEST, WITH THE WARMEST
READINGS IN PLACES WITH NO SNOW COVER INCLUDING SYRACUSE, LIBERAL
AND MEDICINE LODGE. ALTHOUGH DODGE CITY, GARDEN CITY, JETMORE AND
NESS CITY WILL BE IN THE WARM SECTOR ALL DAY, SNOW COVER WILL BE
SLOW TO MELT, RESULTING IN HIGHS ONLY IN THE LOWER 40S BEFORE THE
FRONT ARRIVES. HOWEVER, IF SNOW COVER IS MORE RAPID THAN EXPECTED,
THEN HIGHS COULD REACH INTO THE MID 40S.
BY TONIGHT, SURFACE LEE TROUGHING WILL DEVELOP AHEAD OF THE NEXT
SHORTWAVE TROUGH APPROACHING THE NORTHERN ROCKIES AS THE MID
LEVEL FLOW GAINS A SLIGHT DOWNSLOPE COMPONENT ACROSS THE CENTRAL
ROCKIES. THIS WILL RESULT IN A RETURN TO SOUTH WINDS BY MIDNIGHT
SO THAT TEMPERATURES MAY ACTUALLY REACH LOWS AROUND MIDNIGHT AND
THEN HOLD STEADY OR SLOWLY RISE THEREAFTER.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 252 AM CST THU JAN 31 2013
LONG RANGE MODELS SHOW A TRANQUIL WEATHER PATTERN WITH DRY NORTHWEST
UPPER LEVEL FLOW, A FEW MINOR UPPER LEVEL SHORTWAVE TROUGHS, AND
WEAK CANADIAN COLD FRONTS. THE FIRST WAVE MOVES ACROSS THE CENTRAL
PLAINS ON FRIDAY NIGHT WITH WINDS SHIFTING FROM SOUTH TO NORTH
OVERNIGHT AND A WEAK COLD FRONT. THE NEXT UPPER LEVEL WAVE COMES
ACROSS THE PLAINS FROM THE PACIFIC NORTHWEST ON SUNDAY NIGHT BUT
THIS SYSTEM IS FAIRLY DRY. A STRONGER UPPER LEVEL SHORTWAVE TROUGH
MOVES ACROSS THE NORTHERN PLAINS ON TUESDAY MORNING WITH THE MAIN
UPPER JET STAYING WELL NORTH OF THE CENTRAL PLAINS. THE COLD AIR
ASSOCIATED WITH THIS WAVE STAYS INTO THE UPPER MIDWEST. AFTER THE
WAVE MOVES EAST INTO TUESDAY AND WEDNESDAY A WARMER AIRMASS MOVES
INTO THE WESTERN HIGH PLAINS.
OVERNIGHT LOWS ARE EXPECTED TO WARM FROM THE MID 20S FRIDAY NIGHT
AND SATURDAY NIGHT TO THE 30S INTO WEDNESDAY NIGHT. DAYTIME HIGHS
WARM FROM AROUND 50 ON FRIDAY TO THE MID AND UPPER 50S INTO
WEDNESDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 523 AM CST THU JAN 31 2013
A BACKDOOR ARCTIC COLD FRONT IS FORECAST TO MOVE SOUTHWESTWARD AND
INTO WESTERN KANSAS THIS AFTERNOON WITH SOME LOW STRATUS
DEVELOPING. AHEAD OF THE FRONT EXPECT MID LEVEL CLOUDINESS.
SOUTHWEST TO NORTHWEST WINDS BECOME NORTHEAST TO EASTERLY WITH THE
ARCTIC BOUNDARY WITH IFR CONDITIONS DEVELOPING. THE ARCTIC FRONT
MAY COME A BIT FASTER THAN HRRR AND THE RAP MODELS FORECAST. FOR
NOW WILL HAVE THE ARCTIC FRONT MOVING THROUGH KHYS BY AROUND 19Z,
KDDC BY 23Z, AND KGCK BY 02Z. STRATUS MAY THEN ERODE IN THE KHYS
AREA AFTER 03Z.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 40 17 49 24 / 0 0 0 0
GCK 43 18 51 24 / 0 0 0 0
EHA 51 22 55 25 / 0 0 0 0
LBL 50 21 53 24 / 0 0 0 0
HYS 34 12 44 22 / 0 0 0 0
P28 47 15 46 26 / 0 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...FINCH
SHORT TERM...FINCH
LONG TERM...KRUSE
AVIATION...KRUSE
AREA FORECAST DISCUSSION
NWS GOODLAND KS
412 AM MST THU JAN 31 2013
.SHORT TERM...(TODAY THROUGH SATURDAY NIGHT)
ISSUED AT 412 AM MST THU JAN 31 2013
FORECAST PROBLEMS WILL PROBLEMATIC TEMPERATURE FORECAST INTO TONIGHT
AND HOW MUCH TO WARM UP THE HIGH TEMPERATURES INTO SATURDAY.
SATELLITE SHOWING A BROAD UPPER TROUGH OVER THE TROUGH OVER THE
WESTERN AND CENTRAL PACIFIC WITH A RIDGE ALONG THE WEST COAST OF
NORTH AMERICA. A COUPLE OF SYSTEMS COMING INTO THE RIDGE ARE BEATING
IT DOWN. A STRONG AND COLD SYSTEM IS DIGGING INTO THE NORTH CENTRAL
PORTION OF THE COUNTRY. VERY COLD AIR MASS HAS MOVED FURTHER SOUTH
FROM YESTERDAY AND IS NOT TOO FAR NORTH AND EAST OF OUR AREA.
MODELS INITIALIZED WELL AT JET LEVEL WITH THE CANADIAN...GFS...AND
NAM DOING THE BEST. MODELS INITIALIZED WELL AT MID LEVELS WITH THE
GFS...CANADIAN...AND NAM DOING SLIGHTLY BETTER. LARGER SCALE MODELS
DO NOT HAVE THE BACKDOOR COLD FRONT FAR ENOUGH SOUTH AND WEST BY
06Z...OH SURPRISE. THE RUC HAS CONTINUED TO GET BETTER AS THE
NIGHT HAS PROGRESSED. OUTSIDE OF THE RUC ON THE LOW LEVEL THERMAL
FIELD...THE ECMWF AND GFS WERE DOING A LITTLE BETTER THAN THE UKMET
AND NAM.
TODAY/TONIGHT...VERY THICK CLOUD COVER HAS SPREAD OVER THE AREA
THROUGH THE NIGHT. WHAT THIS HAS DONE HAS PREVENTED ANY FALL OF THE
TEMPERATURES AND IN FACT HAS CAUSED THE TEMPERATURES TO RISE SOME.
NWP OUTPUT MUST BE UNDERDOING THIS CLOUD COVER AND IS TOO COOL WITH
TEMPERATURES. THIS CLOUD COVER IS BEING CAUSED BY STRONG MID TO
UPPER LEVEL JET. SOUNDINGS AND PLAN VIEW RELATIVE HUMIDITY PLOTS SHOW
THIS CLOUD COVER LASTING MOST OF THE DAY...ESPECIALLY IN THE
NORTHEAST PORTION.
BACKDOOR COLD FRONT WITH VERY COLD AIR BEHIND IT HAS BEEN MOVING
STEADILY TOWARD THE AREA THROUGH THE NIGHT AND IS NOT THAT FAR
AWAY. RUC IS CATCHING ONTO THIS AT THIS TIME. INITIALLY WAS GOING TO
CUT HIGH TEMPERATURES FROM GOING FORECAST BUT CLOUD COVER HAS
COMPLICATED THAT. SO WILL BE STARTING MUCH WARMER THAN WHAT MOST OF
THE MODELS SAY. FRONT SAGS ACROSS THE AREA THROUGH THE DAY WITH
SOME LOCATIONS IN THE NORTHEAST HALF TO TWO THIRDS REACHING THEIR
MAX BY 18Z. SO COMBINING REALITY AND THE RUC ADJUSTED MAX
TEMPERATURES UP BUT HAVE EXTREMELY LOW CONFIDENCE ABOUT THIS. DID
NOT GOES AS WARM AS IT BECAUSE OF THE CLOUD COVER. HRRR WOULD
INDICATE HIGH TEMPERATURES ABOUT 10 DEGREES WARMER IN THE SOUTHWEST
PORTION OF THE AREA THAT WHAT I HAVE.
LEFT FRONT QUADRANT OF INCOMING JET WILL CONTINUE TO AFFECT THE
NORTHEAST HALF TO TWO THIRDS OF THE AREA INTO EARLY AFTERNOON.
SEVERAL STATIONS HAVE REPORTED BRIEF PERIODS OF FLURRIES. ALL MODEL
OUTPUT AGREES IN PLACING LIGHT QPF IN THE ABOVE MENTIONED AREA. SREF
PROBABILITIES AGREE WITH THAT. IT MAKES SENSE WITH THE JET...
MESOSCALE FORCING AND LAPSE RATES IN PLACE. HOWEVER...DRIER AIR
IN THE LOWEST LAYERS. SO INTRODUCED SCATTERED FLURRIES THROUGH
MIDDAY WHEN THE FORCING AND MOISTURE LEAVE.
PROBLEMATIC MIN FORECAST AS WELL. WINDS SHIFT AROUND TO A SOUTH
DIRECTION PRETTY QUICKLY. NAM IS THE MOST AGGRESSIVE BUT IS
SUPPORTED BY OTHER MODEL OUTPUT IN BRINGING STRATUS AND FOG DURING
THE LATE EVENING AND OVERNIGHT HOURS. THIS IS AS THE COLD FRONT
RETREATS BACK AS A WARM FRONT AND ALL THE MODELS ARE VERY SIMILAR
IN DOING IT. MINS WILL PROBABLY BE REACHED IN THE EVENING
ESPECIALLY IN THE WEST AND POSSIBLY IN THE SOUTH AND A NON-DIURNAL
CURVE WILL HAVE TO BE INTRODUCED. BELIEVE MODELS ARE TOO COOL AND
WENT ABOVE THE GUIDANCE.
06Z NAM WAS MUCH MORE ROBUST IN BRINGING IN THE STRATUS AND FOG. NAM
HAS BEEN SHOWING THIS FOR A FEW DAYS PLUS THOSE SOUTH WINDS WILL BE
BLOWING ACROSS A SNOW FIELD. SO EXPANDED THE PATCHY FOG THAT WAS IN
THERE.
FRIDAY/FRIDAY NIGHT...STRATUS AND FOG GET PUSHED EAST PRETTY FAST BY
THE STRENGTHENING DOWNSLOPE WINDS. THERE MAY BE SOME HIGHER LEVEL
CLOUD COVER AROUND. INCOMING SHORTWAVE TROUGH IN NORTHWEST FLOW
ALOFT WILL PUSH A WEAK FRONT OR SURFACE TROUGH THROUGH LATER IN THE
DAY BUT IT LOOKS LIKE WINDS WILL BE FROM A DOWNSLOPE DIRECTION. SO
ENDED UP RAISING THE MAXES A LITTLE.
LEFT FRONT QUADRANT OF JET WILL AFFECT THE NORTHERN PORTION OF THE
AREA DURING THE NIGHT AS WELL AS THE ABOVE MENTIONED SHORTWAVE
TROUGH...WHICH HAPPENS TO BE THE ONE TOPPING THE RIDGE RIGHT NOW
NEAR WESTERN CANADA. ALL MODELS AGREE THAT THIS SYSTEM WILL HAVE
A VERY STRONG PV ANOMALY AS WELL. MODELS DO NOT SHOW A LOT OF
MOISTURE IN THE COLUMN BUT STRENGTH OF SYSTEM SHOULD COMPENSATE FOR
THAT. SO EXPANDED THE SPRINKLES AND FLURRIES OVER A LARGER AREA AND
THROUGH THE EVENING HOURS.
SATURDAY/SATURDAY NIGHT...RIDGING AND DRYING ALOFT PUSH INTO THE
AREA FOR SATURDAY. SO WILL HAVE PLENTY OF SUN ALONG WITH STRONG
DOWNSLOPE WINDS. SO RAISED MAXES MORE AND I MAY NOT BE WARM ENOUGH
AS I BELIEVE MODELS ARE TOO COOL.
.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 246 AM MST THU JAN 31 2013
MODEL AGREEMENT IS FAIRLY GOOD IN THE EXTENDED FORECAST. ALL
SOLUTIONS ARE POINTING TO A TAME WEATHER PATTERN WITHOUT ANY BIG
WEATHER CHANGES OR PRECIPITATION CHANCES. A SYSTEM WILL MOVE ACROSS
THE NORTHERN PLAINS AND GREAT LAKES ON MONDAY...BRINGING ONLY A WIND
SHIFT AND TEMPERATURES A DEGREE OR TWO COOLER. AFTER THAT...A RIDGE
OF HIGH PRESSURE BUILDS BACK IN FROM THE WEST.
TEMPERATURES SHOULD BE WELL ABOVE NORMAL FOR THIS TIME OF YEAR
THROUGHOUT THE EXTENDED FORECAST. HIGHS SHOULD BE IN THE 50S FOR
SUNDAY THROUGH TUESDAY...WITH HIGHS CLIMBING INTO THE 60S BY THE
MIDDLE OF NEXT WEEK. GUIDANCE HAS PULLED BACK SOMEWHAT FOR HIGH
TEMPERATURES ON SUNDAY BUT STILL THINK TEMPERATURES NEARING 60 FOR
EASTERN COLORADO IS NOT OUT OF THE QUESTION.
THE ONLY OTHER CONCERN FOR THE EXTENDED FORECAST WAS LOW
TEMPERATURES. THE INITIALIZATION PROCEDURE INPUT LOW TEMPERATURES
THAT WERE LIKELY TOO WARM. CONSIDERING THE ONGOING DROUGHT
CONDITIONS AND MEX AND ECE GUIDANCE SUGGESTING TEMPERATURES MUCH
LOWER THAN THE INITIALIZATION...HAVE LOWERED LOW TEMPERATURES A
DEGREE OR TWO. GUIDANCE IS ALTERED BY CLIMATOLOGICAL DATA SO THIS
COULD BE THE REASON MEX AND ECE GUIDANCE IS BEING HELD DOWN
SOMEWHAT. HOWEVER...THE HIGHER LOW TEMPS SEEMED A LITTLE
UNREASONABLE WITH CLEAR SKIES AND LIGHT WINDS THROUGHOUT THE
EXTENDED PERIOD.
THANKS TO ALL FOR THE COLLABORATION.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1048 PM MST WED JAN 30 2013
VFR CONDITIONS WILL PREVAIL THROUGH THE FORECAST PERIOD. LIGHT
WESTERLY WINDS WILL TURN NORTHWEST AND BECOME GUSTY AFTER
16Z...BECOMING LIGHT AGAIN FOLLOWING SUNSET AFTER 00Z.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...BULLER
LONG TERM...RRH
AVIATION...JSL
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1023 AM EST THU JAN 31 2013
.SYNOPSIS...
COLDER AIR WORKING INTO THE AREA BEHIND A STRONG COLD FRONT WILL
PRODUCE STRONG GUSTY WINDS TODAY...IN ADDITION TO LAKE EFFECT
SNOWS DOWNWIND OF LAKES ERIE AND ONTARIO. BELOW NORMAL
TEMPERATURES AND SCATTERED SHOW SHOWERS WILL CONTINUE INTO THE
WEEKEND...DUE TO A COMBINATION OF LAKE EFFECT SNOW SHOWERS AND
WEAK UPPER LEVEL DISTURBANCES.
&&
.NEAR TERM /THROUGH TONIGHT/...
10 AM UPDATE... OUR CURRENT FCST IS IN EXCELLENT SHAPE ATTM...SO
ONLY COSMETIC CHGS WERE MADE.
AS STG CAA CONTS TO FILTER ACRS THE FA LATE THIS MRNG...LES BANDS
ARE TRYING TO ORGANIZE OFF BOTH LKS ERIE AND ONT. AS JUDGED FROM
THE 12Z RAOBS AT BUF/DTX...THE MIXED LYR EXTENDS UP TO ABT 750
MB...WITH A FAIR MOISTURE SUPPLY UNDERNEATH THE BASE OF THE
INVERSION. GIVEN CONTD CYCLONIC FLOW...FURTHER COOLING WITH
TIME...AND IF ANYTHING...A DEEPENING OF THE SYNOPTIC MOISTURE THIS
AFTN AND EVE...THERE`S NO REASON NOT TO EXPECT THE DVLPMT OF
FAIRLY STG LAKE-EFFECT PLUMES OFF BOTH LKS.
IN-HOUSE CAPE/SHEAR NOMOGRAM SHOWS ENUF OVER-LAND INSTAB THROUGH
THIS EVE (00-03Z)...SO THAT THE BANDS MAY TAKE ON SOMEWHAT OF A CELLULAR
APPEARANCE...AT TIMES. HOWEVER...ORGANIZATION IS NOT LIKELY TO BE
SERIOUSLY COMPROMISED. ALSO...THE CSTAR-DERIVED INLAND EXTENT
APPLICATION DEPICTS A FAIRLY DEEP INLAND PENETRATION THROUGHOUT
THE EVE HRS...AT LEAST...WITH A GOOD UPSTREAM CONNECTION TO
HURON/NRN LK MI/SUPERIOR...AND ALSO STG 0-1 KM SPEED SHEAR. THIS
ALSO SEEMS WELL SUPPORTED BY SIM REFLECTIVITY PRESENTATIONS FROM
THE NAM12...LOCAL ARW...AND HRRR MODELS.
BOTTOM LN...THINGS APPEAR WELL ON TRACK FOR THE LES WRNG IN NRN
ONEIDA...WITH A PD OF VERY HVY SNOW ANTICIPATED...FROM ROUGHLY
22-06Z. GIVEN DEEP MOISTURE...AND EXCELLENT CRYSTAL GROWTH
PARAMETERS...2-3"/HR RATES ARE NOT OUT OF THE QUESTION. ELSEWHERE
(ONONDAGA/MADISON/SRN ONEIDA)...DESPITE SOME ANTICIPATED
WEAKENING LTR TNT...AS THE BAND DROPS SWD...THERE MAY BE ENUF
RESIDUAL INTENSITY FOR ADVSY-LVL ACCUMS. WE`LL RE-VISIT THIS SITN
EARLY THIS AFTN.
ACRS THE TWIN TIERS...SOME CONVECTIVE SHSN ARE LIKELY TO FORM BY
MID TO LATE AFTN...AIDED A BIT BY ADVECTION OF MOISTURE FROM LKS
ERIE AND SRN MI IN STG WRLY FLOW. OVERALL...THOUGH...THE NATURE OF
THEM WILL REMAIN SCTD.
AS FOR THE WINDS...THEY`RE LIKELY TO BE AT THEIR PEAK THROUGH ABT
18Z...WITH A SLOW DIMINISHING TREND THEREAFTER...AS JUDGED FROM
ISALLOBARIC AND MOMENTUM TRANSFER PROGS.
A STEADY OR SLOWLY FALLING TEMP TREND IS WELL HANDLED IN THE
GRIDS...SO ONLY VERY MINOR TWEAKS WERE NEEDED.
PREV DISC... 620 AM...WILL DROP THE FLOOD WATCH FOR ERN ZONES AS
STEADY RAIN IS MOVG OUT. OTRW JUST MINOR NEAR TERM TWEEKS WITH NO
SIG CHGS TO FCST. PREV BLO...
450 AM...DROPPED FLOOD WATCH FOR THE CNTRL SRN TIER AND PORTIONS
OF THE FINGER LAKES AS BACK EDGE OF STEADIER RAIN HAS EXITED THIS
RGN. MAY STILL SEE SOME MINOR FLOODING DUE TO RUNOFF BUT FLS`S
HANDLING THAT. CONVECTIVE FNTL LINE PRODUCED WIND GUSTS IN THE
40-50 MPH RECENTLY AT SYR/BGM. SYNOPTIC SCALE WINDS WILL BE
INCRSNG RAPIDLY LATER THIS MRNG ALL AREAS. PREV BLO...
BACK EDGE OF AREA OF STEADY RAIN AREA MOVING INTO WRN ZONES AS OF
315 AM...CLOSE TO THE PSN OF THE SFC CDFNT...AND WILL CONTINUE IT`S EWD
PROGRESS THROUGH THE EARLY MRNG HRS. SOME OF THE RAIN MAY MIX
BRIEFLY WITH SNOW BEFORE TAPERING OFF THIS MRNG. FLOOD WATCH
REMAINS ON EFFECT...WE HAVE ISSUED SOME FLS`S THUS FAR AND WILL
CONTINUE TO MONITOR CAREFULLY.
MAIN ISSUE TDA WILL BE THE STRONG WINDS DVLPNG THIS MRNG AND
CONTINUING INTO THE AFTN HRS. BASED ON OUR SUSTAINED AND PEAK WIND
GRIDS...WE ADDED STEUBEN...YATES AND SENECA COUNTIES INTO THE
WARNING.
SCATTERED SNOW SHOWERS ARE XPCTD TDA...MAINLY DUE TO LAKE
INFLUENCES. WE COULD SEE -SHSN OFF LAKE ERIE ACRS PORTIONS OF THE
TWIN TIERS THIS AFTN/EVNG. POTNL FOR 2-4 INCHES ACRS PORTIONS OF
WRN STEUBEN TNGT. AFTN SHIFT CAN RE-ASSESS AND DETERMINE IF A LOW
END ADVISORY IS NEEDED HERE.
AS FOR THE NRN ONEIDA LES EVENT...THIS EVENT APPEARS TO BE SIMILAR
TO LAST WEEKS. THE ARW PERFORMED WELL IN THAT CASE...AND THIS
MRNG`S RUC ALSO SHOWS GOOD AGREEMENT EARLY ON IN THE PD. IT
APPEARS THAT THE BAND WILL NOT MAKE A MOVE INTO NRN ONEIDA UNTIL
LATE THIS AFTN...PERSISTING OVER THAT AREA TIL ARND 06Z BEFORE
DROPPING SWD AS FLOW BCMS MORE WNWLY. AS THIS OCCURS...MESO MDLS
SHOW THE BAND OVER LAKE ONTARIO DROPPING TO A PSN NEAR/ALONG THE
SRN SHORE OF LAKE ONTARIO LATE TNGT/TWDS DAYBREAK. THIS IS WHAT
OCCURRED WITH THE LAST BAND...AND RESULTED IN RAPID WEAKENING OF
THE BAND OVER THE BGM CWA DUE (AT LEAST IN PART) TO THE LOSS OF
OVER-LAKE TRAJECTORY. THIS IS ALSO HINTED AT IN THE MESO MDLS FRI
MRNG. FOR NOW WE HAVE THE BAND DROPPING SWD INTO ONON/MAD IN THE
09-12Z TIME FRAME...WITH POTNL FOR LOW END ADVISORY ACCUMS MAINLY
OVER NW ONON. GIVEN THE NUMEROUS HEADLINES ALREADY IN EFFECT AND
THE FACT WE HAVE SOME TIME TO TAKE A CLOSER LOOK AT THIS...WE WILL
JUST MENTION THE POTNL IN THE HWO AND LET THE DAY SHIFT ISSUE
HEADLINES FOR THIS EVENT IF NEEDED.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
A COUPLE OF CLIPPER-TYPE SYSTEMS WILL AFFECT THIS WEEKEND...WITH
SCATTERED SNOW SHOWERS. A MORE WDSPRD AREA OF LGT SNOW COULD DVLP
IN THE WARM ADVECTION PTRN AHEAD OF THE CLIPPER APRCHNG SAT NGT.
IN GNRL...CHC POPS FOR -SHSN AND BLO NORMAL TEMPS.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
GRIDS WERE ADJUSTED SOME TO ACCOUNT FOR LATEST HPC GUIDANCE AND
GFS/ECMWF MODELS. NO BIG CHANGE TO GOING FORECAST OVERALL...BUT I
DID UPGRADE POPS INTO LIKELY CATEGORY FOR CENTRAL NY AND AT LEAST
HIGHER CHANCE FOR NORTHEAST PA SUNDAY WITH FAIR AGREEMENT ON BEING
INVOLVED IN MERGER BETWEEN DEVELOPING COASTAL LOW AND INCOMING
NORTHERN STREAM SYSTEM/CLIPPER. COULD EASILY RESULT IN LIGHT
COATING OF SNOW. ANOTHER WEAK CLIPPER CONTINUES TO LOOK POSSIBLE
MONDAY NIGHT/TUESDAY.
PREVIOUS DISCUSSION...
FOLLOWED HPC GUIDANCE. MODELS ARE SIMILAR WITH NO LARGE STORMS.
REMAIN UNDER A NORTHEAST US UPPER LEVEL TROF. SEASONABLE WEATHER
WITH WEAK LOW PRESSURE SYSTEMS FOLLOWED BY LAKE EFFECT. ALL PRECIP
WILL BE SNOW WITH HIGHS AROUND 30 AND LOWS IN THE TEENS. THE WEAK
SYSTEMS GO THROUGH SUNDAY AND MONDAY NIGHT...WITH LAKE EFFECT ON
THE OTHER DAYS. COULD BE A 12 HOUR DRY BREAK BETWEEN SYSTEMS WITH
WEAK HIGH PRESSURE MON AFTN.
&&
.AVIATION /15Z THURSDAY THROUGH MONDAY/...
12Z UPDATE...
STRONG COLD FRONT IS JUST FINISHING ITS BLAST THROUGH THE
AREA...TAKING THE STEADIER RAIN SHOWERS WITH IT. WINDS WILL HAVE A
MUCH EASIER TIME MIXING DOWN IN THE COLD AIR BEHIND THE
FRONT...ALLOWING WESTERLY GUSTS FREQUENTLY IN THE 30-40 KT RANGE.
GUSTS AT KSYR AND PERHAPS KRME WILL EVEN TOP OUT AROUND 35-45 KTS
AT TIMES TODAY. EXPECTING SCT-BKN CLOUD DECK WITH SCT -SHSN AND
MVFR CIG FOR SOME TERMINALS. THOUGH GENERALLY VFR TO MVFR IN TAFS
TODAY WITH THE SNOW FLURRIES...SOME TERMINALS WILL HAVE TO WATCH
FOR BRIEF SURPRISE IFR VIS FROM A HEAVIER LAKE EFFECT SNOW SHOWER.
THE MAIN LAKE ONTARIO SNOW BAND WILL AT FIRST DEVELOP NORTH OF THE
AREA THIS AFTERNOON...BUT SHOULD EDGE SOUTH ENOUGH TO INVOLVE KRME
IN OCCASIONAL IFR VIS AFTER 03Z...AND BY 09Z ONWARD FOR KSYR.
.OUTLOOK...
FRI THRU SAT NGT...MVFR-IFR FROM LAKE -SHSN IN CENTRAL NY.
SUN...A COLD FRONT WITH POSSIBLE MVFR AND IFR SNOW
SUN NGT-MON...MORE MVFR/IFR LAKE -SHSN MAINLY CENTRAL NY.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...WIND ADVISORY UNTIL 7 PM EST THIS EVENING FOR PAZ038>040-043-
044-047-048-072.
NY...WIND ADVISORY UNTIL 7 PM EST THIS EVENING FOR NYZ023>025-044-
045-055-056-062.
HIGH WIND WARNING UNTIL 7 PM EST THIS EVENING FOR NYZ009-
015>018-022-036-037-046-057.
LAKE EFFECT SNOW WARNING FROM 1 PM THIS AFTERNOON TO 7 AM EST
FRIDAY FOR NYZ009.
&&
$$
SYNOPSIS...
NEAR TERM...MLJ
SHORT TERM...
LONG TERM...MDP/TAC
AVIATION...MDP
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
651 AM EST THU JAN 31 2013
.SYNOPSIS...
COLDER AIR WORKING INTO THE AREA BEHIND A STRONG COLD FRONT WILL
PRODUCE STRONG GUSTY WINDS TODAY...IN ADDITION TO LAKE EFFECT
SNOWS DOWNWIND OF LAKES ERIE AND ONTARIO. BELOW NORMAL
TEMPERATURES AND SCATTERED SHOW SHOWERS WILL CONTINUE INTO THE
WEEKEND...DUE TO A COMBINATION OF LAKE EFFECT SNOW SHOWERS AND
WEAK UPPER LEVEL DISTURBANCES.
&&
.NEAR TERM /THROUGH TONIGHT/...
620 AM...WILL DROP THE FLOOD WATCH FOR ERN ZONES AS STEADY RAIN IS
MOVG OUT. OTRW JUST MINOR NEAR TERM TWEEKS WITH NO SIG CHGS TO
FCST. PREV BLO...
450 AM...DROPPED FLOOD WATCH FOR THER CNTRL SRN TIER AND PORTIONS
OF THE FINGER LAKES AS BACKEDGE OF STEADIER RAIN HAS EXITED THIS
RGN. MAY STILL SEE SOME MINOR FLOODING DUE TO RUNOFF BUT FLS`S
HANDLING THAT. CONVECTIVE FNTL LINE PRODUCED WIND GUSTS IN THE
40-50 MPH RECENTLY AT SYR/BGM. SYNOPTIC SCALE WINDS WILL BE
INCRSNG RAPIDLY LATER THIS MRNG ALL AREAS. PREV BLO...
BACKEDGE OF AREA OF STEADY RAIN AREA MOVING INTO WRN ZONES AS OF
315 AM...CLOSE TO THE PSN OF THE SFC CDFNT...AND WILL CONTINUE IT`S EWD
PROGRESS THROUGH THE EARLY MRNG HRS. SOME OF THE RAIN MAY MIX
BRIEFLY WITH SNOW BEFORE TAPERING OFF THIS MRNG. FLOOD WATCH
REMAINS ON EFFECT...WE HAVE ISSUED SOME FLS`S THUS FAR AND WILL
CONTINUE TO MONITOR CAREFULLY.
MAIN ISSUE TDA WILL BE THE STRONG WINDS DVLPNG THIS MRNG AND
CONTINUING INTO THE AFTN HRS. BASED ON OUR SUSTAINED AND PEAK WIND
GRIDS...WE ADDED STEUBEN...YATES AND SENECA COUNTIES INTO THE
WARNING.
SCATTERED SNOW SHOWERS ARE XPCTD TDA...MAILY DUE TO LAKE
INFLUENCES. WE COULD SEE -SHSN OFF LAKE ERIE ACRS PORTIONS OF THE
TWIN TIERS THIS AFTN/EVNG. POTNL FOR 2-4 INCHES ACRS PORTIONS OF
WRN STEUBEN TNGT. AFTN SHIFT CAN RE-ASSESS AND DETERMINE IF A LOW
END ADVISORY IS NEEDED HERE.
AS FOR THE NRN ONEIDA LES EVENT...THIS EVENT APPEARS TO BE SIMILAR
TO LAST WEEKS. THE ARW PERFORMED WELL IN THAT CASE...AND THIS
MRNG`S RUC ALSO SHOWS GOOD AGREEMENT EARLY ON IN THE PD. IT
APPEARS THAT THE BAND WILL NOT MAKE A MOVE INTO NRN ONEIDA UNTIL
LATE THIS AFTN...PERSISTING OVER THAT AREA TIL ARND 06Z BEFORE
DROPPING SWD AS FLOW BCMS MORE WNWLY. AS THIS OCCURS...MESO MDLS
SHOW THE BAND OVER LAKE ONTARIO DROPPING TO A PSN NEAR/ALONG THE
SRN SHORE OF LAKE ONTARIO LATE TNGT/TWDS DAYBREAK. THIS IS WHAT
OCCURRED WITH THE LAST BAND...AND RESULTED IN RAPID WEAKENING OF
TEH BAND OVER THE BGM CWA DUE (AT LEAST IN PART) TO THE LOSS OF
OVER-LAKE TRAJECTORY. THIS IS ALSO HINTED AT IN THE MESO MDLS FRI
MRNG. FOR NOW WE HAVE THE BAND DROPPING SWD INTO ONON/MAD IN THE
09-12Z TIME FRAME...WITH POTNL FOR LOW END ADVISORY ACCUMS MAINLY
OVER NW ONON. GIVEN THE NUMEROUS HEADLINES ALREADY IN EFFECT AND
THE FACT WE HAVE SOME TIME TO TAKE A CLOSER LOOK AT THIS...WE WILL
JUST MENTION THE POTNL IN THE HWO AND LET THE DAYSHIFT ISSUE
HEADLINES FOR THIS EVENT IF NEEDED.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
A COUPLE OF CLIPPER-TYPE SYSTEMS WILL AFFECT THIS WEEKEND...WITH
SCATTERED SNOW SHOWERS. A MORE WDSPRD AREA OF LGT SNOW COULD DVLP
IN THE WARM ADVECTION PTRN AHEAD OF THE CLIPPER APRCHNG SAT NGT.
IN GNRL...CHC POPS FOR -SHSN AND BLO NORMAL TEMPS.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
GRIDS WERE ADJUSTED SOME TO ACCOUNT FOR LATEST HPC GUIDANCE AND
GFS/ECMWF MODELS. NO BIG CHANGE TO GOING FORECAST OVERALL...BUT I
DID UPGRADE POPS INTO LIKELY CATEGORY FOR CENTRAL NY AND AT LEAST
HIGHER CHANCE FOR NORTHEAST PA SUNDAY WITH FAIR AGREEMENT ON BEING
INVOLVED IN MERGER BETWEEN DEVELOPING COASTAL LOW AND INCOMING
NORTHERN STREAM SYSTEM/CLIPPER. COULD EASILY RESULT IN LIGHT
COATING OF SNOW. ANOTHER WEAK CLIPPER CONTINUES TO LOOK POSSIBLE
MONDAY NIGHT/TUESDAY.
PREVIOUS DISCUSSION...
FOLLOWED HPC GUIDANCE. MODELS ARE SIMILAR WITH NO LARGE STORMS.
REMAIN UNDER A NORTHEAST US UPPER LEVEL TROF. SEASONABLE WEATHER
WITH WEAK LOW PRESSURE SYSTEMS FOLLOWED BY LAKE EFFECT. ALL PRECIP
WILL BE SNOW WITH HIGHS AROUND 30 AND LOWS IN THE TEENS. THE WEAK
SYSTEMS GO THROUGH SUNDAY AND MONDAY NIGHT...WITH LAKE EFFECT ON
THE OTHER DAYS. COULD BE A 12 HOUR DRY BREAK BETWEEN SYSTEMS WITH
WEAK HIGH PRESSURE MON AFTN.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
12Z UPDATE...
STRONG COLD FRONT IS JUST FINISHING ITS BLAST THROUGH THE
AREA...TAKING THE STEADIER RAIN SHOWERS WITH IT. WINDS WILL HAVE A
MUCH EASIER TIME MIXING DOWN IN THE COLD AIR BEHIND THE
FRONT...ALLOWING WESTERLY GUSTS FREQUENTLY IN THE 30-40 KT RANGE.
GUSTS AT KSYR AND PERHAPS KRME WILL EVEN TOP OUT AROUND 35-45 KTS
AT TIMES TODAY. EXPECTING SCT-BKN CLOUD DECK WITH SCT -SHSN AND
MVFR CIG FOR SOME TERMINALS. THOUGH GENERALLY VFR TO MVFR IN TAFS
TODAY WITH THE SNOW FLURRIES...SOME TERMINALS WILL HAVE TO WATCH
FOR BRIEF SURPRISE IFR VIS FROM A HEAVIER LAKE EFFECT SNOW SHOWER.
THE MAIN LAKE ONTARIO SNOW BAND WILL AT FIRST DEVELOP NORTH OF THE
AREA THIS AFTERNOON...BUT SHOULD EDGE SOUTH ENOUGH TO INVOLVE KRME
IN OCCASIONAL IFR VIS AFTER 03Z...AND BY 09Z ONWARD FOR KSYR.
.OUTLOOK...
FRI THRU SAT NGT...MVFR-IFR FROM LAKE -SHSN IN CENTRAL NY.
SUN...A COLD FRONT WITH POSSIBLE MVFR AND IFR SNOW
SUN NGT-MON...MORE MVFR/IFR LAKE -SHSN MAINLY CENTRAL NY.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...WIND ADVISORY UNTIL 7 PM EST THIS EVENING FOR PAZ038>040-043-
044-047-048-072.
NY...WIND ADVISORY UNTIL 7 PM EST THIS EVENING FOR NYZ023>025-044-
045-055-056-062.
HIGH WIND WARNING UNTIL 7 PM EST THIS EVENING FOR NYZ009-
015>018-022-036-037-046-057.
LAKE EFFECT SNOW WARNING FROM 1 PM THIS AFTERNOON TO 7 AM EST
FRIDAY FOR NYZ009.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...
LONG TERM...MDP/TAC
AVIATION...MDP
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
620 AM EST THU JAN 31 2013
.SYNOPSIS...
COLDER AIR WORKING INTO THE AREA BEHIND A STRONG COLD FRONT WILL
PRODUCE STRONG GUSTY WINDS TODAY...IN ADDITION TO LAKE EFFECT
SNOWS DOWNWIND OF LAKES ERIE AND ONTARIO. BELOW NORMAL
TEMPERATURES AND SCATTERED SHOW SHOWERS WILL CONTINUE INTO THE
WEEKEND...DUE TO A COMBINATION OF LAKE EFFECT SNOW SHOWERS AND
WEAK UPPER LEVEL DISTURBANCES.
&&
.NEAR TERM /THROUGH TONIGHT/...
620 AM...WILL DROP THE FLOOD WATCH FOR ERN ZONES AS STEADY RAIN IS
MOVG OUT. OTRW JUST MINOR NEAR TERM TWEEKS WITH NO SIG CHGS TO
FCST. PREV BLO...
450 AM...DROPPED FLOOD WATCH FOR THER CNTRL SRN TIER AND PORTIONS
OF THE FINGER LAKES AS BACKEDGE OF STEADIER RAIN HAS EXITED THIS
RGN. MAY STILL SEE SOME MINOR FLOODING DUE TO RUNOFF BUT FLS`S
HANDLING THAT. CONVECTIVE FNTL LINE PRODUCED WIND GUSTS IN THE
40-50 MPH RECENTLY AT SYR/BGM. SYNOPTIC SCALE WINDS WILL BE
INCRSNG RAPIDLY LATER THIS MRNG ALL AREAS. PREV BLO...
BACKEDGE OF AREA OF STEADY RAIN AREA MOVING INTO WRN ZONES AS OF
315 AM...CLOSE TO THE PSN OF THE SFC CDFNT...AND WILL CONTINUE IT`S EWD
PROGRESS THROUGH THE EARLY MRNG HRS. SOME OF THE RAIN MAY MIX
BRIEFLY WITH SNOW BEFORE TAPERING OFF THIS MRNG. FLOOD WATCH
REMAINS ON EFFECT...WE HAVE ISSUED SOME FLS`S THUS FAR AND WILL
CONTINUE TO MONITOR CAREFULLY.
MAIN ISSUE TDA WILL BE THE STRONG WINDS DVLPNG THIS MRNG AND
CONTINUING INTO THE AFTN HRS. BASED ON OUR SUSTAINED AND PEAK WIND
GRIDS...WE ADDED STEUBEN...YATES AND SENECA COUNTIES INTO THE
WARNING.
SCATTERED SNOW SHOWERS ARE XPCTD TDA...MAILY DUE TO LAKE
INFLUENCES. WE COULD SEE -SHSN OFF LAKE ERIE ACRS PORTIONS OF THE
TWIN TIERS THIS AFTN/EVNG. POTNL FOR 2-4 INCHES ACRS PORTIONS OF
WRN STEUBEN TNGT. AFTN SHIFT CAN RE-ASSESS AND DETERMINE IF A LOW
END ADVISORY IS NEEDED HERE.
AS FOR THE NRN ONEIDA LES EVENT...THIS EVENT APPEARS TO BE SIMILAR
TO LAST WEEKS. THE ARW PERFORMED WELL IN THAT CASE...AND THIS
MRNG`S RUC ALSO SHOWS GOOD AGREEMENT EARLY ON IN THE PD. IT
APPEARS THAT THE BAND WILL NOT MAKE A MOVE INTO NRN ONEIDA UNTIL
LATE THIS AFTN...PERSISTING OVER THAT AREA TIL ARND 06Z BEFORE
DROPPING SWD AS FLOW BCMS MORE WNWLY. AS THIS OCCURS...MESO MDLS
SHOW THE BAND OVER LAKE ONTARIO DROPPING TO A PSN NEAR/ALONG THE
SRN SHORE OF LAKE ONTARIO LATE TNGT/TWDS DAYBREAK. THIS IS WHAT
OCCURRED WITH THE LAST BAND...AND RESULTED IN RAPID WEAKENING OF
TEH BAND OVER THE BGM CWA DUE (AT LEAST IN PART) TO THE LOSS OF
OVER-LAKE TRAJECTORY. THIS IS ALSO HINTED AT IN THE MESO MDLS FRI
MRNG. FOR NOW WE HAVE THE BAND DROPPING SWD INTO ONON/MAD IN THE
09-12Z TIME FRAME...WITH POTNL FOR LOW END ADVISORY ACCUMS MAINLY
OVER NW ONON. GIVEN THE NUMEROUS HEADLINES ALREADY IN EFFECT AND
THE FACT WE HAVE SOME TIME TO TAKE A CLOSER LOOK AT THIS...WE WILL
JUST MENTION THE POTNL IN THE HWO AND LET THE DAYSHIFT ISSUE
HEADLINES FOR THIS EVENT IF NEEDED.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
A COUPLE OF CLIPPER-TYPE SYSTEMS WILL AFFECT THIS WEEKEND...WITH
SCATTERED SNOW SHOWERS. A MORE WDSPRD AREA OF LGT SNOW COULD DVLP
IN THE WARM ADVECTION PTRN AHEAD OF THE CLIPPER APRCHNG SAT NGT.
IN GNRL...CHC POPS FOR -SHSN AND BLO NORMAL TEMPS.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
GRIDS WERE ADJUSTED SOME TO ACCOUNT FOR LATEST HPC GUIDANCE AND
GFS/ECMWF MODELS. NO BIG CHANGE TO GOING FORECAST OVERALL...BUT I
DID UPGRADE POPS INTO LIKELY CATEGORY FOR CENTRAL NY AND AT LEAST
HIGHER CHANCE FOR NORTHEAST PA SUNDAY WITH FAIR AGREEMENT ON BEING
INVOLVED IN MERGER BETWEEN DEVELOPING COASTAL LOW AND INCOMING
NORTHERN STREAM SYSTEM/CLIPPER. COULD EASILY RESULT IN LIGHT
COATING OF SNOW. ANOTHER WEAK CLIPPER CONTINUES TO LOOK POSSIBLE
MONDAY NIGHT/TUESDAY.
PREVIOUS DISCUSSION...
FOLLOWED HPC GUIDANCE. MODELS ARE SIMILAR WITH NO LARGE STORMS.
REMAIN UNDER A NORTHEAST US UPPER LEVEL TROF. SEASONABLE WEATHER
WITH WEAK LOW PRESSURE SYSTEMS FOLLOWED BY LAKE EFFECT. ALL PRECIP
WILL BE SNOW WITH HIGHS AROUND 30 AND LOWS IN THE TEENS. THE WEAK
SYSTEMS GO THROUGH SUNDAY AND MONDAY NIGHT...WITH LAKE EFFECT ON
THE OTHER DAYS. COULD BE A 12 HOUR DRY BREAK BETWEEN SYSTEMS WITH
WEAK HIGH PRESSURE MON AFTN.
&&
.AVIATION /11Z THURSDAY THROUGH MONDAY/...
06Z UPDATE...
STRONG WET SYSTEM IS PROGRESSING THROUGH THE REGION. SSE WIND
AHEAD OF THE FRONT...WITH STRONG SSW FLOW NOT FAR OFF THE SURFACE.
FOR KRME AND KAVP...LIKELY MEETING LLWS THRESHOLD AND THUS
INCLUDED INITIALLY IN TAFS. HOWEVER...SURFACE WIND WILL ABRUPTLY
SHIFT TO SW WITH BRIEF HEAVY SHOWERS AS FRONT PASSES...WITH TIMING
AS INDICATED IN TAFS. THOUGH IFR NOT OUT OF QUESTION WITH
FRONT...MAINLY MVFR IS ANTICIPATED AND HAS OCCURRED UPSTREAM.
BEHIND FRONT...WINDS WILL HAVE A MUCH EASIER TIME MIXING
DOWN...MITIGATING ANY FURTHER LLWS BUT ALSO ALLOWING GUSTS
FREQUENTLY IN THE 30-40 KT RANGE. KSYR-KRME COULD EVEN GET A BIT
HIGHER THAN THAT THIS AFTERNOON. SCT-BKN CLOUD DECK DURING THE
DAYTIME HOURS...EVENTUALLY WITH SCT -SHSN AND MVFR CIG FOR SOME
TERMINALS. LAKE ONTARIO SNOW BAND WILL AT FIRST DEVELOP NORTH OF
THE AREA THIS AFTERNOON...BUT SHOULD EDGE SOUTH ENOUGH TO INVOLVE
KRME IN OCCASIONAL IFR VIS 00Z-06Z FRIDAY...AND NOT LONG AFTER
THAT FOR KSYR.
.OUTLOOK...
LATE THU NGT THRU SAT NGT...MVFR-IFR FROM LAKE -SHSN IN CENTRAL NY.
SUN...A COLD FRONT WITH POSSIBLE MVFR AND IFR SNOW
SUN NGT-MON...MORE MVFR/IFR LAKE -SHSN MAINLY CENTRAL NY.
&&
.HYDROLOGY...
CONSENSUS OF MODEL AND MAN MADE GUID PROGS PUTS 1 TO UP TO 2.5
INCHES WITH THE HEAVIEST RAIN AXIS FURTHER WEST ACROSS THE FINGER
LAKES AND CHEMUNG BASINS OF NY. WILL HAVE TWO BATCHES WITH THE
INITIAL BATCH ALREADY IN WRN PA AND WRN NY NOW. THIS FIRST BATCH
MOVES QUICKLY THROUGH THIS AFTN. RAINFALL THIS AFTN UP TO HALF AN
INCH. QUICK RESPONSE ON STREAMS BUT NO FLOODING INITIALLY. THE
COLD FRONT WILL COME THROUGH LATE EVE AND EARLY MORNING WITH MORE
HEAVY RAIN. ANOTHER QUICK INCH IN LESS THAN 6 HOURS WHICH WILL BE
MOSTLY RUNOFF. STREAMS AND RIVERS WILL RESPOND QUICKLY. FLASH
FLOODING POSSIBLE...FOLLOWED BY MINOR RIVER FLOODING.
FLOOD WATCH CONTINUES FOR ENTIRE CWA STARTING AT 4 PM INTO
THURSDAY MORNING. RIVER FLOOD WARNINGS JUST ISSUED FOR
WEST BRANCH DELAWARE RIVER AT WALTON
TIOUGHNIOGA RIVER AT CORTLAND
CHENANGO RIVER AT SHERBURNE
SUSQUEHANNA RIVER AT VESTAL
SUSQUEHANNA RIVER AT WAVERLY/SAYRE
SUSQUEHANNA RIVER AT TOWANDA
SUSQUEHANNA RIVER AT MESHOPPEN
SUSQUEHANNA RIVER NEAR WILKES-BARRE
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...WIND ADVISORY UNTIL 7 PM EST THIS EVENING FOR PAZ038>040-043-
044-047-048-072.
NY...WIND ADVISORY UNTIL 7 PM EST THIS EVENING FOR NYZ023>025-044-
045-055-056-062.
HIGH WIND WARNING UNTIL 7 PM EST THIS EVENING FOR NYZ009-
015>018-022-036-037-046-057.
LAKE EFFECT SNOW WARNING FROM 1 PM THIS AFTERNOON TO 7 AM EST
FRIDAY FOR NYZ009.
&&
$$
LONG TERM...MDP/TAC
AVIATION...MDP
HYDROLOGY...
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
454 AM EST THU JAN 31 2013
.SYNOPSIS...
COLDER AIR WORKING INTO THE AREA BEHIND A STRONG COLD FRONT WILL
PRODUCE STRONG GUSTY WINDS TODAY...IN ADDITION TO LAKE EFFECT
SNOWS DOWNWIND OF LAKES ERIE AND ONTARIO. BELOW NORMAL
TEMPERATURES AND SCATTERED SHOW SHOWERS WILL CONTINUE INTO THE
WEEKEND...DUE TO A COMBINATION OF LAKE EFFECT SNOW SHOWERS AND
WEAK UPPER LEVEL DISTURBANCES.
&&
.NEAR TERM /THROUGH TONIGHT/...
450 AM...DROPPED FLOOD WATCH FOR THER CNTRL SRN TIER AND PORTIONS
OF THE FINGER LAKES AS BACKEDGE OF STEADIER RAIN HAS EXITED THIS
RGN. MAY STILL SEE SOME MINOR FLOODING DUE TO RUNOFF BUT FLS`S
HANDLING THAT. CONVECTIVE FNTL LINE PRODUCED WIND GUSTS IN THE
40-50 MPH RECENTLY AT SYR/BGM. SYNOPTIC SCALE WINDS WILL BE
INCRSNG RAPIDLY LATER THIS MRNG ALL AREAS. PREV BLO...
BACKEDGE OF AREA OF STEADY RAIN AREA MOVING INTO WRN ZONES AS OF
315 AM...CLOSE TO THE PSN OF THE SFC CDFNT...AND WILL CONTINUE IT`S EWD
PROGRESS THROUGH THE EARLY MRNG HRS. SOME OF THE RAIN MAY MIX
BRIEFLY WITH SNOW BEFORE TAPERING OFF THIS MRNG. FLOOD WATCH
REMAINS ON EFFECT...WE HAVE ISSUED SOME FLS`S THUS FAR AND WILL
CONTINUE TO MONITOR CAREFULLY.
MAIN ISSUE TDA WILL BE THE STRONG WINDS DVLPNG THIS MRNG AND
CONTINUING INTO THE AFTN HRS. BASED ON OUR SUSTAINED AND PEAK WIND
GRIDS...WE ADDED STEUBEN...YATES AND SENECA COUNTIES INTO THE
WARNING.
SCATTERED SNOW SHOWERS ARE XPCTD TDA...MAILY DUE TO LAKE
INFLUENCES. WE COULD SEE -SHSN OFF LAKE ERIE ACRS PORTIONS OF THE
TWIN TIERS THIS AFTN/EVNG. POTNL FOR 2-4 INCHES ACRS PORTIONS OF
WRN STEUBEN TNGT. AFTN SHIFT CAN RE-ASSESS AND DETERMINE IF A LOW
END ADVISORY IS NEEDED HERE.
AS FOR THE NRN ONEIDA LES EVENT...THIS EVENT APPEARS TO BE SIMILAR
TO LAST WEEKS. THE ARW PERFORMED WELL IN THAT CASE...AND THIS
MRNG`S RUC ALSO SHOWS GOOD AGREEMENT EARLY ON IN THE PD. IT
APPEARS THAT THE BAND WILL NOT MAKE A MOVE INTO NRN ONEIDA UNTIL
LATE THIS AFTN...PERSISTING OVER THAT AREA TIL ARND 06Z BEFORE
DROPPING SWD AS FLOW BCMS MORE WNWLY. AS THIS OCCURS...MESO MDLS
SHOW THE BAND OVER LAKE ONTARIO DROPPING TO A PSN NEAR/ALONG THE
SRN SHORE OF LAKE ONTARIO LATE TNGT/TWDS DAYBREAK. THIS IS WHAT
OCCURRED WITH THE LAST BAND...AND RESULTED IN RAPID WEAKENING OF
TEH BAND OVER THE BGM CWA DUE (AT LEAST IN PART) TO THE LOSS OF
OVER-LAKE TRAJECTORY. THIS IS ALSO HINTED AT IN THE MESO MDLS FRI
MRNG. FOR NOW WE HAVE THE BAND DROPPING SWD INTO ONON/MAD IN THE
09-12Z TIME FRAME...WITH POTNL FOR LOW END ADVISORY ACCUMS MAINLY
OVER NW ONON. GIVEN THE NUMEROUS HEADLINES ALREADY IN EFFECT AND
THE FACT WE HAVE SOME TIME TO TAKE A CLOSER LOOK AT THIS...WE WILL
JUST MENTION THE POTNL IN THE HWO AND LET THE DAYSHIFT ISSUE
HEADLINES FOR THIS EVENT IF NEEDED.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
A COUPLE OF CLIPPER-TYPE SYSTEMS WILL AFFECT THIS WEEKEND...WITH
SCATTERED SNOW SHOWERS. A MORE WDSPRD AREA OF LGT SNOW COULD DVLP
IN THE WARM ADVECTION PTRN AHEAD OF THE CLIPPER APRCHNG SAT NGT.
IN GNRL...CHC POPS FOR -SHSN AND BLO NORMAL TEMPS.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
GRIDS WERE ADJUSTED SOME TO ACCOUNT FOR LATEST HPC GUIDANCE AND
GFS/ECMWF MODELS. NO BIG CHANGE TO GOING FORECAST OVERALL...BUT I
DID UPGRADE POPS INTO LIKELY CATEGORY FOR CENTRAL NY AND AT LEAST
HIGHER CHANCE FOR NORTHEAST PA SUNDAY WITH FAIR AGREEMENT ON BEING
INVOLVED IN MERGER BETWEEN DEVELOPING COASTAL LOW AND INCOMING
NORTHERN STREAM SYSTEM/CLIPPER. COULD EASILY RESULT IN LIGHT
COATING OF SNOW. ANOTHER WEAK CLIPPER CONTINUES TO LOOK POSSIBLE
MONDAY NIGHT/TUESDAY.
PREVIOUS DISCUSSION...
FOLLOWED HPC GUIDANCE. MODELS ARE SIMILAR WITH NO LARGE STORMS.
REMAIN UNDER A NORTHEAST US UPPER LEVEL TROF. SEASONABLE WEATHER
WITH WEAK LOW PRESSURE SYSTEMS FOLLOWED BY LAKE EFFECT. ALL PRECIP
WILL BE SNOW WITH HIGHS AROUND 30 AND LOWS IN THE TEENS. THE WEAK
SYSTEMS GO THROUGH SUNDAY AND MONDAY NIGHT...WITH LAKE EFFECT ON
THE OTHER DAYS. COULD BE A 12 HOUR DRY BREAK BETWEEN SYSTEMS WITH
WEAK HIGH PRESSURE MON AFTN.
&&
.AVIATION /10Z THURSDAY THROUGH MONDAY/...
06Z UPDATE...
STRONG WET SYSTEM IS PROGRESSING THROUGH THE REGION. SSE WIND
AHEAD OF THE FRONT...WITH STRONG SSW FLOW NOT FAR OFF THE SURFACE.
FOR KRME AND KAVP...LIKELY MEETING LLWS THRESHOLD AND THUS
INCLUDED INITIALLY IN TAFS. HOWEVER...SURFACE WIND WILL ABRUPTLY
SHIFT TO SW WITH BRIEF HEAVY SHOWERS AS FRONT PASSES...WITH TIMING
AS INDICATED IN TAFS. THOUGH IFR NOT OUT OF QUESTION WITH
FRONT...MAINLY MVFR IS ANTICIPATED AND HAS OCCURRED UPSTREAM.
BEHIND FRONT...WINDS WILL HAVE A MUCH EASIER TIME MIXING
DOWN...MITIGATING ANY FURTHER LLWS BUT ALSO ALLOWING GUSTS
FREQUENTLY IN THE 30-40 KT RANGE. KSYR-KRME COULD EVEN GET A BIT
HIGHER THAN THAT THIS AFTERNOON. SCT-BKN CLOUD DECK DURING THE
DAYTIME HOURS...EVENTUALLY WITH SCT -SHSN AND MVFR CIG FOR SOME
TERMINALS. LAKE ONTARIO SNOW BAND WILL AT FIRST DEVELOP NORTH OF
THE AREA THIS AFTERNOON...BUT SHOULD EDGE SOUTH ENOUGH TO INVOLVE
KRME IN OCCASIONAL IFR VIS 00Z-06Z FRIDAY...AND NOT LONG AFTER
THAT FOR KSYR.
.OUTLOOK...
LATE THU NGT THRU SAT NGT...MVFR-IFR FROM LAKE -SHSN IN CENTRAL NY.
SUN...A COLD FRONT WITH POSSIBLE MVFR AND IFR SNOW
SUN NGT-MON...MORE MVFR/IFR LAKE -SHSN MAINLY CENTRAL NY.
&&
.HYDROLOGY...
CONSENSUS OF MODEL AND MAN MADE GUID PROGS PUTS 1 TO UP TO 2.5
INCHES WITH THE HEAVIEST RAIN AXIS FURTHER WEST ACROSS THE FINGER
LAKES AND CHEMUNG BASINS OF NY. WILL HAVE TWO BATCHES WITH THE
INITIAL BATCH ALREADY IN WRN PA AND WRN NY NOW. THIS FIRST BATCH
MOVES QUICKLY THROUGH THIS AFTN. RAINFALL THIS AFTN UP TO HALF AN
INCH. QUICK RESPONSE ON STREAMS BUT NO FLOODING INITIALLY. THE
COLD FRONT WILL COME THROUGH LATE EVE AND EARLY MORNING WITH MORE
HEAVY RAIN. ANOTHER QUICK INCH IN LESS THAN 6 HOURS WHICH WILL BE
MOSTLY RUNOFF. STREAMS AND RIVERS WILL RESPOND QUICKLY. FLASH
FLOODING POSSIBLE...FOLLOWED BY MINOR RIVER FLOODING.
FLOOD WATCH CONTINUES FOR ENTIRE CWA STARTING AT 4 PM INTO
THURSDAY MORNING. RIVER FLOOD WARNINGS JUST ISSUED FOR
WEST BRANCH DELAWARE RIVER AT WALTON
TIOUGHNIOGA RIVER AT CORTLAND
CHENANGO RIVER AT SHERBURNE
SUSQUEHANNA RIVER AT VESTAL
SUSQUEHANNA RIVER AT WAVERLY/SAYRE
SUSQUEHANNA RIVER AT TOWANDA
SUSQUEHANNA RIVER AT MESHOPPEN
SUSQUEHANNA RIVER NEAR WILKES-BARRE
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...FLOOD WATCH UNTIL 7 AM EST THIS MORNING FOR PAZ039-040-043-044-
047-048-072.
WIND ADVISORY UNTIL 7 PM EST THIS EVENING FOR PAZ038>040-043-
044-047-048-072.
NY...FLOOD WATCH UNTIL 7 AM EST THIS MORNING FOR NYZ009-018-036-037-
044>046-056-057-062.
WIND ADVISORY UNTIL 7 PM EST THIS EVENING FOR NYZ023>025-044-
045-055-056-062.
HIGH WIND WARNING UNTIL 7 PM EST THIS EVENING FOR NYZ009-
015>018-022-036-037-046-057.
LAKE EFFECT SNOW WARNING FROM 1 PM THIS AFTERNOON TO 7 AM EST
FRIDAY FOR NYZ009.
&&
$$
LONG TERM...MDP/TAC
AVIATION...MDP
HYDROLOGY...
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
937 AM EST THU JAN 31 2013
.SYNOPSIS...
COOL HIGH PRESSURE WILL BUILD IN FROM THE WEST TODAY...WITH BELOW
NORMAL TEMPERATURES EXPECTED. IT WILL BE BREEZY TODAY... ALTHOUGH
WINDS WILL NOT BE AS STRONG AS LAST NIGHT. A SERIES OF DRY COLD
FRONTS WILL MOVE ACROSS THE AREA. THE FIRST FRONT WILL CROSS THE
AREA FRIDAY FOLLOWED BY ANOTHER ON SUNDAY AND YET ANOTHER ON TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 930 AM THURSDAY...THE SEASONS HAVE CHANGED YET AGAIN WITH
YESTERDAY`S SPRING-LIKE WEATHER REPLACED BY A RETURN TO WINTER
TODAY. COLD ADVECTION ON WESTERLY WINDS BEHIND LAST NIGHT`S STRONG
COLD FRONT WILL ALMOST PERFECTLY BALANCE NEARLY FULL SUNSHINE TODAY
AND TEMPERATURES WILL STRUGGLE JUST TO RISE A FEW DEGREES BY
AFTERNOON...REACHING 53-56 DEGREES AREAWIDE. THE 12Z GSO SOUNDING
WAS BEST SIMULATED BY THE 12Z NAM AND RUC MODELS...AND THESE ARE THE
TWO MODELS I BLENDED FOR MY UPDATED FORECAST TODAY. DOWNWARD
REVISIONS HAVE BEEN MADE TO DEWPOINT FORECASTS FOR THE AFTERNOON
HOURS WITH LOWER 20S DEWPOINTS EXPECTED TO MIX DOWN FROM A RESERVOIR
OF VERY DRY AIR ALOFT. PRECIPITABLE WATER VALUES TODAY SHOULD RANGE
FROM 0.20 TO 0.25 INCHES.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 3 AM THURSDAY...SHORTWAVE ROUNDING BASE OF MID LEVEL TROUGH
EARLY FRI HELPS DRIVE A REINFORCING SHOT OF COLD AIR INTO THE
REGION. DRY COLD FRONT PUSHES OFFSHORE BY MIDDAY WITH A PERIOD OF
BRIEF BUT STRONG COLD ADVECTION ENDING LATE FRI NIGHT. TEMP DROP
WILL BE SIGNIFICANT WITH GUIDANCE SHOWING 850 TEMPS DECREASING BY
AS MUCH AS 10C IN SOME PLACES IN UNDER 12 HOURS. DEEP WEST TO
NORTHWEST FLOW FRI INTO FRI NIGHT HELPS KEEP SKIES CLEAR. PATTERN
BECOMES LESS AMPLIFIED AND MORE PROGRESSIVE LATE FRI
NIGHT...SHUTTING OFF COLD ADVECTION. MORE PROGRESSIVE EVOLUTION OF
MID LEVEL PATTERN HELPS MOVE CENTER OF SURFACE RIDGE AXIS OVER THE
REGION FOR SAT MORNING...ALLOWING FOR SOME RADIATIONAL COOLING. DO
NOT ANTICIPATE EFFECT TO BE VERY STRONG BUT TYPICAL COLD SPOTS
WILL FLIRT WITH TEENS FOR LOWS. HIGHS FRI WILL STRUGGLE TO REACH
CLIMO WHILE LOWS WILL DROP INTO THE LOW TO MID 20S IN MOST AREAS
SAT MORNING.
SURFACE RIDGE AXIS SHIFTS OFFSHORE SAT WITH WEAK RETURN FLOW SETTING
UP FOR THE END OF THE PERIOD. ALOFT ANOTHER SHORTWAVE HELPS AMPLIFY
THE MID LEVEL PATTERN...RESULTING IN A SHORT PERIOD OF DEEP
WEST-SOUTHWEST FLOW AHEAD OF ANOTHER COLD FRONT MOVING INTO THE
REGION AS THE PERIOD ENDS. ANTICIPATE AN INCREASE IN MID AND
UPPER LEVEL CLOUD ASSOCIATED WITH THIS WAVE BUT DURATION OF RETURN
FLOW IS NOT ENOUGH TO BRING SIGNIFICANT MOISTURE BACK INTO THE
REGION BEFORE THE FRONT PASSES. ALTHOUGH SOME GUIDANCE IS POINTING
TO SOME LIGHT ISOLATED PRECIP EARLY SUN MORNING DO NOT THINK THIS
WILL BE THE CASE. WILL MAINTAIN A POP FORECAST AROUND 10 SAT
NIGHT. TEMPERATURES REMAIN BELOW CLIMO SAT BUT END UP MUCH CLOSER
TO CLIMO SAT NIGHT.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 3 AM THURSDAY...A RATHER REPETITIVE PATTERN FOR THE EXTENDED AS
AREAS OF HIGH PRESSURE PUSH OFFSHORE AHEAD OF A SERIES OF WEAK
COLD FRONTS.
FIRST COLD FRONT WILL CROSS THE AREA VERY EARLY SUNDAY MORNING.
LIMITED FORCING COMBINED WITH ONLY MARGINAL PWATS SUGGESTS FROPA
WILL BE DRY...AND ONLY ACT TO REINFORCE THE COOL AIR.
HOWEVER...ANY WEAK CAA REMAINS WELL DISPLACED BEHIND THE
FRONT...SO SUNDAY WILL END UP BEING WARMER THAN
SATURDAY...ALTHOUGH BOTH DAYS WILL BE AROUND TO SLIGHTLY BELOW
CLIMO.
ANOTHER LARGE BUT WEAK AREA OF HIGH PRESSURE BUILDS DOWN FROM THE NW
LATE SUNDAY AND PERSISTS INTO TUESDAY WHILE SLOWLY DRIFTING ACROSS
THE REGION. THIS CONTINUES THE COOL AND DRY WEATHER WITH NEAR TO
SLIGHTLY-BELOW SEASONABLE TEMPS. THIS HIGH PRESSURE THEN DRIFTS
OFFSHORE TUESDAY AHEAD OF ANOTHER COLD FRONT PROGGED TO CROSS THE
AREA LATE IN THE DAY. GUIDANCE SHOWING CONSIDERABLE AMPLITUDE
DIFFERENCES IN THE TROUGH DRIVING THIS FRONT WHICH WILL HAVE
SIGNIFICANT IMPACT ON PRECIP POTENTIAL. FOR NOW WILL KEEP INHERITED
SCHC/SILENT POP FOR D6 SINCE BENEFICIAL CHANGES CANNOT BE MADE AT
THIS TIME. TUESDAY WILL LIKELY BE THE WARMEST DAY OF THE PERIOD
THOUGH AHEAD OF THE COLD FRONT...WITH TEMPS RETURNING TO BELOW CLIMO
FOR WEDNESDAY AS ANOTHER AREA OF HIGH PRESSURE RIDGES DOWN FROM THE
NW.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
AS OF 12Z...SCATTERED TO BROKEN MVFR LEVEL CLOUDS TRAVERSING
MAINLY THE KILM TERMINAL WILL SHIFT QUICKLY OFFSHORE 13-14Z.
SCATTERED TO BROKEN VFR LEVEL LOW CLOUDS WILL LIKELY PERSIST AT
LEAST THROUGH THE EARLY MORNING HOURS FROM KLBT/KILM NORTH.
SIGNIFICANT DRYING OF THE AIRMASS SHOULD LEAD TO GENERALLY CLEAR
SKIES AT ALL TERMINALS BY LATE MORNING. A TIGHT PRESSURE GRADIENT
WILL PRODUCE WSW-W WINDS 15-25 KNOTS WITH ISOLATED GUSTS 30-35
KNOTS EARLY THIS MORNING. WIND SPEEDS WILL GRADUALLY EASE THROUGH
THE DAY. WILL NOT INCLUDE WIND SHEAR IN TAFS THIS MORNING AS KLTX
WIND PROFILE DATA AND SURFACE REPORTS SUGGESTS WIND SPEEDS ARE
GRADUALLY INCREASING SFC-2K. VFR THIS EVENING AND OVERNIGHT WITH
WSW WINDS 6-12 KNOTS.
EXTENDED OUTLOOK...VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 930 AM THURSDAY...EARLIER BLOWOUT TIDE CONDITIONS HAVE ABATED.
WATER LEVELS AS MEASURED AT THE OFFICIAL NOS (NATIONAL OCEAN
SERVICE) TIDE GAUGES REACHED -1.92 FT MLLW AT WRIGHTSVILLE BEACH...
AND -1.50 FT MLLW AT MYRTLE BEACH. FOR THE NEXT LOW TIDE JUST AFTER
4 PM...WESTERLY WINDS SHOULD BE DIMINISHING WITH LESS IMPACT ON
COASTAL WATER LEVELS. OTHERWISE...WEST WINDS AROUND 30 KNOTS WITH
FREQUENT GALE-FORCE GUSTS ARE STILL OCCURRING ACROSS THE AREA THIS
MORNING. I WISH THE GALE WARNING WERE STILL UP AS GUSTS AT THE
FRYING PAN SHOALS BUOY CONTINUE TO ECLIPSE 40 KNOTS...AND WITH 12
FOOT SEAS I AM FAIRLY CERTAIN SUSTAINED GALE-FORCE WINDS ARE
OCCURRING BEYOND 15 MILES FROM SHORE. THESE VERY STRONG WINDS SHOULD
BEGIN TO ABATE OVER THE NEXT 2 HOURS AS HIGH PRESSURE OVER SOUTHERN
LOUISIANA NOSES TOWARD THE CAROLINAS AND OUR PRESSURE GRADIENT
BEGINS TO WEAKEN.
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 3 AM THURSDAY...SMALL CRAFT ADVISORY CONTINUES INTO FRI BEFORE
PASSAGE OF COLD FRONT AND DEVELOPMENT OF OFFSHORE FLOW PUSHES 6
FT SEAS BEYOND 20 NM. STRONG BUT BRIEF COLD ADVECTION DURING THE
SECOND HALF OF FRI INTO FRI NIGHT MAY REQUIRE A PERIOD OF SCEC
HEADLINES. HIGH PRESSURE BUILDS IN FROM THE WEST LATE FRI NIGHT
THEN SHIFTS OVER THE WATERS DURING SAT. WEAKENING GRADIENT ALLOWS
WIND SPEEDS TO DROP FROM A SOLID 20 KT FRI TO UNDER 10 KT BY SAT
MORNING. RETURN FLOW STARTS TO DEVELOPING SAT AFTERNOON AS HIGH
PRESSURE SLIDES EAST OF THE WATERS. GRADIENT BECOMES PINCHED AHEAD
OF NEXT COLD FRONT...WITH SOUTHWEST WINDS INCREASING TO 15 KT AS
THE PERIOD ENDS. SEAS SUBSIDE DURING FRI...DROPPING FROM 4 TO 7 FT
AT THE START OF THE PERIOD TO 3 TO 4 FT FRI EVENING. SEAS FALL
FURTHER...CLOSE TO 2 FT...EARLY SAT BEFORE STARTING TO BUILD BACK
CLOSER TO 3 TO 4 FT LATE IN THE PERIOD AS SOUTHWEST WINDS
INCREASE.
LONG TERM /SUNDAY THROUGH MONDAY/...
AS OF 3 AM THURSDAY...A COLD FRONT WILL CROSS THE WATERS SUNDAY...
TURNING WINDS TO THE W/NW AT 10-15 KTS ON SUNDAY BEFORE SLOWLY
EASING TO LIGHT AND VARIABLE AGAIN MONDAY AS HIGH PRESSURE BUILDS
BACK OVER THE WATERS. SEAS WILL BE PRIMARILY WIND-DRIVEN THROUGH
THE PERIOD...INCREASING FOR A SHORT TIME SUNDAY UP TO 2-4 FT...
THEN DECREASING TO 1 TO 2 FT MONDAY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 1 PM EST FRIDAY FOR
AMZ250-252-254-256.
&&
$$
NEAR TERM...TRA
SHORT TERM...III
LONG TERM...JDW
AVIATION...MRR
AREA FORECAST DISCUSSION
NWS RALEIGH NC
650 AM EST THU JAN 31 2013
.SYNOPSIS...
A STRONG COLD FRONT WILL CROSS THE STATE EARLY THIS MORNING....
FOLLOWED BY COLDER AND DRIER AIR TODAY. A WEAK AND MOSTLY DRY COLD
FRONT SYSTEM WILL CROSS THE AREA EARLY FRIDAY WITH HIGH PRESSURE
BUILDING BACK IN FOR THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 600 AM THURSDAY...
SQUALL LINE HAS PUSHES EAST OF THE CWA AND TO TORNADO WATCH WAS
ALLOWED TO EXPIRE AT 2AM. WINDS IMMEDIATELY BEHIND THE LINE
CONTINUE TO GUST TO 30-35KT...BUT DIE OFF WITH WESTWARD EXTENT AWAY
FROM THE LINE. THE IS AN AREA OF STRONGER GUSTS OVER NORTHERN GA
AND WESTERN SC...BUT HRRR WIND GUST FIELDS SUGGEST THESE WINDS WILL
SHIFT EAST ACROSS SC. THUS...WE WILL ALLOW THE WIND ADVISORY TO
EXPIRE AT 4AM.
THE COLD FRONT...CURRENTLY EMERGING EAST OF THE MOUNTAINS..WILL PUSH
EAST ACROSS THE CWA THIS MORNING AND IN TO THE COASTAL PLAIN BY
12Z. EXPECT WINDS WILL GUST PERIODICALLY TO AROUND 20KT WITH THE
FRONT...THEN BECOME MORE CONSISTENT IN THE 20-25KT RANGE OUT OF THE
WEST BEHIND THE FRONT TODAY. A FEW SHOWERS ARE POSSIBLE ALONG THE
FRONT...MAINLY NORTH...AND DRYING ALOFT SHOULD LIMIT COVERAGE IN THE
SOUTH. DESPITE CLEARING BEHIND THE FRONT...MODEST COLD ADVECTION
WILL DOMINATE THE FIRST HALF OF THE DAY... KEEPING TEMPS FROM RISING
MORE THAN 4-6 DEGREES ON MOST PLACES...RANGING FROM THE MID 40S
NORTHWEST TO LOWER 50S SOUTHEAST.
ANOTHER SHORTWAVE TROUGH DIGGING SOUTHEAST OUT OF CANADA WILL SWING
ACROSS THE MID ATLANTIC STATES LATE TONIGHT. STRENGTHENING DPVA AND
A BRIEF SHOT OF 60-80M HEIGHT FALLS FOCUSED ALONG THE NC/VA BORDER
AND NORTHWARD...COMBINED WITH A BAND OF MID LEVEL MOISTURE CROSSING
THE MOUNTAINS MAY BE SUFFICIENT TO CAUSE FLURRIES...MAINLY IN THE
09-12Z TIME FRAME. THE GFS HAS THE MOST ABUNDANT MOISTURE IN
GENERAL...WITH MOISTURE REACHING TO -10C IN A BAND THAT SPANS THE
ENTIRE CWA. HOWEVER...MOISTURE WITHIN THE ICE NUCLEATION ZONE IS
ONLY PRESENT NORTH OF I-40 AND MOST PRONOUNCED NEAR THE NC/VA
BORDER. THE LIMITED DURATION OF LIFT AND MOISTURE..AS WELL AS A
RELATIVELY DRY BOUNDARY LAYER AND POTENTIAL FOR SUBLIMATION...WILL
KEEP THIS TO A NO IMPACT EVENT. LOWS IN THE UPPER 20S TO LOWER 30S.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 250 AM WEDNESDAY...
FOR FRIDAY/FRIDAY NIGHT: THE RISK OF A QUICK FLURRY OR SPRINKLE IS
LIKELY TO STRETCH PAST SUNRISE FRIDAY AS THE MID LEVEL SHORTWAVE
TROUGH SHIFTS EASTWARD OFF THE MIDATLANTIC COAST AND THE REINFORCING
CLIPPER COLD FRONT MOVES EAST OF CENTRAL NC. THE LOWEST 10 KFT LAYER
DRIES OUT RAPIDLY BY MID MORNING WITH WINDS IN THIS LAYER VEERING TO
NORTHWESTERLY AND STRONG DEEP SUBSIDENCE COMMENCING AS THE 160 KT
UPPER JET CORE SHIFTS FURTHER EAST OFF THE VA/NC COAST. EXPECT
GENERALLY CLEAR SKIES FROM LATE MORNING THROUGH THE DAY WITH A DRY
AND HIGHLY STABLE COLUMN. THE LOW LEVEL THERMAL STRUCTURE MIXING UP
TO ABOUT 800 MB SUPPORTS CHILLY HIGHS FROM 36 NORTH TO 46 NEAR THE
SC BORDER. TEMPS SHOULD DROP OFF QUICKLY AFTER SUNSET FRIDAY EVENING
THEN LEVEL OFF AS WE BEGIN TO SEE INCREASING HIGH AND MID CLOUDS
OVERNIGHT... AS MID LEVEL DPVA AND HEIGHT FALLS ARRIVE AHEAD OF THE
NEXT CLIPPER. BUT THESE CLOUDS SHOULD BE FAIRLY THIN AND GIVEN THE
VERY COLD YUKON ORIGINS OF THIS INCOMING AIR MASS AND THE WINDS
GOING NEARLY CALM AS THE SURFACE RIDGE AXIS SETTLES OVERHEAD...
STILL ANTICIPATE ABNORMALLY COLD LOWS OF 18-24.
FOR SATURDAY/SATURDAY NIGHT: THE NEXT CLIPPER FRONT WILL STRETCH
FROM THE GREAT LAKES ACROSS MO SATURDAY MORNING... WITH AN
ASSOCIATED WEAK WARM FRONT EXTENDING FROM IL TO SC. THE WARM FRONT
WILL SWEEP NORTHEASTWARD THROUGH THE NC SATURDAY AFTERNOON AS THE
SURFACE RIDGE PUSHES OFF THE COAST. CLOUD COVER WILL CONTINUE TO
THICKEN AND LOWER WITH INCREASING MID LEVEL HEIGHT FALLS IN ADVANCE
OF THE MID LEVEL SHORTWAVE TROUGH APPROACHING NC. DESPITE THE
CLOUDS... THE ENSUING SOUTHWEST LOW LEVEL FLOW SHOULD ALLOW
THICKNESSES AND TEMPS TO REBOUND TO JUST SLIGHTLY BELOW NORMAL...
HIGHS OF 45-50. MODELS DEPICT A 35-40 KT LOW LEVEL SOUTHWESTERLY JET
MOVING THROUGH THE REGION LATE SATURDAY AFTERNOON INTO THE
EVENING... COINCIDENT WITH FORECAST SOUNDINGS SHOWING DEEPENING
MOISTURE FROM 850 MB UP BEYOND 500 MB... AND AHEAD OF A MID LEVEL
VORTICITY MAX AND SHORTWAVE TROUGH THAT WILL BE TAKING ON A NEGATIVE
TILT AS IT PASSES THROUGH NC. THE SUBCLOUD LAYER SHOULD REMAIN
FAIRLY DRY HOWEVER... SO MUCH OF WHAT FALLS IS LIKELY TO
EVAPORATE/SUBLIMATE. GIVEN THAT THE WEB BULB PROFILE ON FORECAST
SOUNDINGS SHOULD BE CLOSE TO FREEZING AT THE SURFACE DURING THIS
TIME IN THE NORTHERN FORECAST AREA AND LIKELY JUST ABOVE FREEZING IN
THE SOUTH... A COMBINATION OF LIGHT SPRINKLES OR FLURRIES STILL
APPEARS REASONABLE. INTERESTING TO NOTE ARE THE GFS`S LAPSE RATES
ALOFT WHICH REACH 7.0 C/KM 800-500 MB SATURDAY NIGHT... SUGGESTING
THAT IF DYNAMIC FORCING FOR ASCENT IS STRONG ENOUGH TO AUGMENT
INSTABILITY ALOFT... WE MAY SEE A LIGHTNING STRIKE OR TWO IF THE
GFS`S STRONGER VORTICITY MAX IS CORRECT. AT ANY RATE... WILL LEAVE
IN A LOW CHANCE POP AREAWIDE FOR LATE AFTERNOON WELL INTO THE
NIGHT... BUT AGAIN EXPECT LITTLE MORE THAN TRACE TO A COUPLE OF
HUNDREDTHS OF AN INCH OF LIQUID EQUIVALENT AS THE SURFACE AIR
REMAINS DRY. SKIES SHOULD CLEAR OUT LATE SATURDAY NIGHT WITH NVA IN
THE WAKE OF THE EXITING TROUGH. LOWS 30-35. -GIH
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 315 AM WEDNESDAY...
FOR SUNDAY: ONE LAST SHOT OF POLAR STREAM ENERGY DIVES DOWN THE SW
SIDE OF THE MEAN TROUGH... FROM THE GREAT LAKES THROUGH WV AND
ACROSS DELMARVA WITH A SURFACE CLIPPER COLD FRONT NOT FAR BEHIND. IT
APPEARS THAT THE MID LEVELS WILL HAVE DRIED OUT AND STABILIZED BY
THIS TIME... AND MOISTURE IS UNIMPRESSIVE IN THE SURFACE-BASED MIXED
LAYER AS WELL... SO WILL SHOWS SOME CLOUDS SWEEPING THROUGH THE AREA
BUT WITH NO PRECIP CHANCES. THICKNESSES REMAIN SEASONABLE SO EXPECT
HIGHS OF 49-55.
FOR SUNDAY NIGHT THROUGH WEDNESDAY: THE COLD LONGWAVE TROUGH OVER
EASTERN NOAM FINALLY RETREATS NORTHWARD AND WEAKENS WITH RISING
HEIGHTS AND A FLATTENING FLOW OVER OUR REGION LASTING THROUGH MID
WEEK... AS MODIFYING SURFACE HIGH PRESSURE BUILDS IN. THE HIGH IS
INITIALLY CHILLY AND TEMPS MONDAY SHOULD RUN SEVERAL DEGREES BELOW
NORMAL... PARTICULARLY WITH MILKY SUNSHINE TO LIMIT INSOLATION AS
ONE LAST MINOR WAVE AND MID LEVEL SPEED MAX MOVE IN FROM THE WEST.
TEMPS SHOULD THEN RECOVER TO ABOVE NORMAL TUESDAY INTO WEDNESDAY AS
THE SURFACE HIGH QUICKLY MODIFIES AS IT EASES TO OUR SOUTH. THE
GFS/ECMWF BOTH SHOWS THIS HIGH PUSHING SOUTHWARD AND WEAKENING AS A
BACKDOOR FRONT APPROACHES FROM THE NORTH... ALTHOUGH THE ECMWF
SWINGS A POTENT NORTHERN STREAM WAVE THROUGH THE MIDATLANTIC
REGION... AND AS A RESULT HAS A MUCH STRONGER AND FASTER BACKDOOR
FRONT AND A NOTABLE COOLDOWN BY WEDNESDAY. WILL STAY WITH THE LESS
AMPLIFIED ROUTE OF THE GFS AT THIS TIME... AND KEEP TEMPS MILD ON
WEDNESDAY WITH FAIR SKIES. -GIH
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
AS OF 650 AM THURSDAY...
COLD CURRENTLY PUSHING EAST THROUGH THE AREA WILL FORCE THE
REMAINING SHOWERS AND 3-4K FT CEILINGS BETWEEN KRWI AND KFAY TO MOVE
EAST OF THE AREA. THE STRONGEST WESTERLY WINDS ARE CURRENTLY OVER
THE SOUTHERN PORTIONS OF THE AREA...WHERE 25-30KT GUSTS ARE STILL
BEING REPORTED. THESE WINDS WILL WEAKEN THIS MORNING ONCE THE FRONT
MOVES THROUGH THE AREA. HOWEVER...THE APPROACH OF ANOTHER
DISTURBANCE FROM THE NORTHWEST AND STRENGTHENING LOW LEVEL WINDS
WILL LEAD TO 15-20KT SUSTAINED WESTERLY WINDS WITH GUSTS APPROACHING
30KT POSSIBLE LATER THIS AFTERNOON. WHILE VFR CEILINGS AND VSBYS
WILL PREVAIL...A CROSSWIND MAY CAUSE SOME ADVERSE AVIATION
CONDITIONS FOR SMALLER AIRCRAFT.
LOSS OF HEATING SHOULD ALLOW WINDS TO WEAKEN AFTER 00Z..THOUGH
SPORADIC GUSTS TO AROUND 20KT MAY CONTINUE INTO THE OVERNIGHT
HOURS. MID CLOUDS WILL INCREASE LATE TONIGHT AS THE AFOREMENTIONED
DISTURBANCE NEARS THE AREA.
OUTLOOK...VFR CONDITIONS ARE GENERALLY EXPECTED TO PREVAIL THROUGH
EARLY NEXT WEEK. A DISTURBANCE FORECAST TO CROSS THE AREA
SATURDAY/SATURDAY NIGHT WILL BRING ADDED CLOUD COVER AND THE
POTENTIAL FOR A SHORT PERIOD OF RAIN OR SNOW.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE
&&
$$
SYNOPSIS...SMITH
NEAR TERM...SMITH
SHORT TERM...HARTFIELD
LONG TERM...HARTFIELD
AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
325 AM EST THU JAN 31 2013
.SYNOPSIS...
A STRONG COLD FRONT WILL CROSS THE STATE EARLY THIS MORNING....
FOLLOWED BY COLDER AND DRIER AIR TODAY. A WEAK AND MOSTLY DRY COLD
FRONT SYSTEM WILL CROSS THE AREA EARLY FRIDAY WITH HIGH PRESSURE
BUILDING BACK IN FOR THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 255 AM THURSDAY...
A WIND ADVISORY REMAINS IN EFFECT ACROSS ALL OF CENTRAL NC THROUGH 4
AM LST.
SQUALL LINE HAS PUSHES EAST OF THE CWA AND TO TORNADO WATCH WAS
ALLOWED TO EXPIRE AT 2AM. WINDS IMMEDIATELY BEHIND THE LINE
CONTINUE TO GUST TO 30-35KT...BUT DIE OFF WITH WESTWARD EXTENT AWAY
FROM THE LINE. THE IS AN AREA OF STRONGER GUSTS OVER NORTHERN GA
AND WESTERN SC...BUT HRRR WIND GUST FIELDS SUGGEST THESE WINDS WILL
SHIFT EAST ACROSS SC. THUS...WE WILL ALLOW THE WIND ADVISORY TO
EXPIRE AT 4AM.
THE COLD FRONT...CURRENTLY EMERGING EAST OF THE MOUNTAINS..WILL PUSH
EAST ACROSS THE CWA THIS MORNING AND IN TO THE COASTAL PLAIN BY
12Z. EXPECT WINDS WILL GUST PERIODICALLY TO AROUND 20KT WITH THE
FRONT...THEN BECOME MORE CONSISTENT IN THE 20-25KT RANGE OUT OF THE
WEST BEHIND THE FRONT TODAY. A FEW SHOWERS ARE POSSIBLE ALONG THE
FRONT...MAINLY NORTH...AND DRYING ALOFT SHOULD LIMIT COVERAGE IN THE
SOUTH. DESPITE CLEARING BEHIND THE FRONT...MODEST COLD ADVECTION
WILL DOMINATE THE FIRST HALF OF THE DAY... KEEPING TEMPS FROM RISING
MORE THAN 4-6 DEGREES ON MOST PLACES...RANGING FROM THE MID 40S
NORTHWEST TO LOWER 50S SOUTHEAST.
ANOTHER SHORTWAVE TROUGH DIGGING SOUTHEAST OUT OF CANADA WILL SWING
ACROSS THE MID ATLANTIC STATES LATE TONIGHT. STRENGTHENING DPVA AND
A BRIEF SHOT OF 60-80M HEIGHT FALLS FOCUSED ALONG THE NC/VA BORDER
AND NORTHWARD...COMBINED WITH A BAND OF MID LEVEL MOISTURE CROSSING
THE MOUNTAINS MAY BE SUFFICIENT TO CAUSE FLURRIES...MAINLY IN THE
09-12Z TIME FRAME. THE GFS HAS THE MOST ABUNDANT MOISTURE IN
GENERAL...WITH MOISTURE REACHING TO -10C IN A BAND THAT SPANS THE
ENTIRE CWA. HOWEVER...MOISTURE WITHIN THE ICE NUCLEATION ZONE IS
ONLY PRESENT NORTH OF I-40 AND MOST PRONOUNCED NEAR THE NC/VA
BORDER. THE LIMITED DURATION OF LIFT AND MOISTURE..AS WELL AS A
RELATIVELY DRY BOUNDARY LAYER AND POTENTIAL FOR SUBLIMATION...WILL
KEEP THIS TO A NO IMPACT EVENT. LOWS IN THE UPPER 20S TO LOWER 30S.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 250 AM WEDNESDAY...
FOR FRIDAY/FRIDAY NIGHT: THE RISK OF A QUICK FLURRY OR SPRINKLE IS
LIKELY TO STRETCH PAST SUNRISE FRIDAY AS THE MID LEVEL SHORTWAVE
TROUGH SHIFTS EASTWARD OFF THE MIDATLANTIC COAST AND THE REINFORCING
CLIPPER COLD FRONT MOVES EAST OF CENTRAL NC. THE LOWEST 10 KFT LAYER
DRIES OUT RAPIDLY BY MID MORNING WITH WINDS IN THIS LAYER VEERING TO
NORTHWESTERLY AND STRONG DEEP SUBSIDENCE COMMENCING AS THE 160 KT
UPPER JET CORE SHIFTS FURTHER EAST OFF THE VA/NC COAST. EXPECT
GENERALLY CLEAR SKIES FROM LATE MORNING THROUGH THE DAY WITH A DRY
AND HIGHLY STABLE COLUMN. THE LOW LEVEL THERMAL STRUCTURE MIXING UP
TO ABOUT 800 MB SUPPORTS CHILLY HIGHS FROM 36 NORTH TO 46 NEAR THE
SC BORDER. TEMPS SHOULD DROP OFF QUICKLY AFTER SUNSET FRIDAY EVENING
THEN LEVEL OFF AS WE BEGIN TO SEE INCREASING HIGH AND MID CLOUDS
OVERNIGHT... AS MID LEVEL DPVA AND HEIGHT FALLS ARRIVE AHEAD OF THE
NEXT CLIPPER. BUT THESE CLOUDS SHOULD BE FAIRLY THIN AND GIVEN THE
VERY COLD YUKON ORIGINS OF THIS INCOMING AIR MASS AND THE WINDS
GOING NEARLY CALM AS THE SURFACE RIDGE AXIS SETTLES OVERHEAD...
STILL ANTICIPATE ABNORMALLY COLD LOWS OF 18-24.
FOR SATURDAY/SATURDAY NIGHT: THE NEXT CLIPPER FRONT WILL STRETCH
FROM THE GREAT LAKES ACROSS MO SATURDAY MORNING... WITH AN
ASSOCIATED WEAK WARM FRONT EXTENDING FROM IL TO SC. THE WARM FRONT
WILL SWEEP NORTHEASTWARD THROUGH THE NC SATURDAY AFTERNOON AS THE
SURFACE RIDGE PUSHES OFF THE COAST. CLOUD COVER WILL CONTINUE TO
THICKEN AND LOWER WITH INCREASING MID LEVEL HEIGHT FALLS IN ADVANCE
OF THE MID LEVEL SHORTWAVE TROUGH APPROACHING NC. DESPITE THE
CLOUDS... THE ENSUING SOUTHWEST LOW LEVEL FLOW SHOULD ALLOW
THICKNESSES AND TEMPS TO REBOUND TO JUST SLIGHTLY BELOW NORMAL...
HIGHS OF 45-50. MODELS DEPICT A 35-40 KT LOW LEVEL SOUTHWESTERLY JET
MOVING THROUGH THE REGION LATE SATURDAY AFTERNOON INTO THE
EVENING... COINCIDENT WITH FORECAST SOUNDINGS SHOWING DEEPENING
MOISTURE FROM 850 MB UP BEYOND 500 MB... AND AHEAD OF A MID LEVEL
VORTICITY MAX AND SHORTWAVE TROUGH THAT WILL BE TAKING ON A NEGATIVE
TILT AS IT PASSES THROUGH NC. THE SUBCLOUD LAYER SHOULD REMAIN
FAIRLY DRY HOWEVER... SO MUCH OF WHAT FALLS IS LIKELY TO
EVAPORATE/SUBLIMATE. GIVEN THAT THE WEB BULB PROFILE ON FORECAST
SOUNDINGS SHOULD BE CLOSE TO FREEZING AT THE SURFACE DURING THIS
TIME IN THE NORTHERN FORECAST AREA AND LIKELY JUST ABOVE FREEZING IN
THE SOUTH... A COMBINATION OF LIGHT SPRINKLES OR FLURRIES STILL
APPEARS REASONABLE. INTERESTING TO NOTE ARE THE GFS`S LAPSE RATES
ALOFT WHICH REACH 7.0 C/KM 800-500 MB SATURDAY NIGHT... SUGGESTING
THAT IF DYNAMIC FORCING FOR ASCENT IS STRONG ENOUGH TO AUGMENT
INSTABILITY ALOFT... WE MAY SEE A LIGHTNING STRIKE OR TWO IF THE
GFS`S STRONGER VORTICITY MAX IS CORRECT. AT ANY RATE... WILL LEAVE
IN A LOW CHANCE POP AREAWIDE FOR LATE AFTERNOON WELL INTO THE
NIGHT... BUT AGAIN EXPECT LITTLE MORE THAN TRACE TO A COUPLE OF
HUNDREDTHS OF AN INCH OF LIQUID EQUIVALENT AS THE SURFACE AIR
REMAINS DRY. SKIES SHOULD CLEAR OUT LATE SATURDAY NIGHT WITH NVA IN
THE WAKE OF THE EXITING TROUGH. LOWS 30-35. -GIH
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 315 AM WEDNESDAY...
FOR SUNDAY: ONE LAST SHOT OF POLAR STREAM ENERGY DIVES DOWN THE SW
SIDE OF THE MEAN TROUGH... FROM THE GREAT LAKES THROUGH WV AND
ACROSS DELMARVA WITH A SURFACE CLIPPER COLD FRONT NOT FAR BEHIND. IT
APPEARS THAT THE MID LEVELS WILL HAVE DRIED OUT AND STABILIZED BY
THIS TIME... AND MOISTURE IS UNIMPRESSIVE IN THE SURFACE-BASED MIXED
LAYER AS WELL... SO WILL SHOWS SOME CLOUDS SWEEPING THROUGH THE AREA
BUT WITH NO PRECIP CHANCES. THICKNESSES REMAIN SEASONABLE SO EXPECT
HIGHS OF 49-55.
FOR SUNDAY NIGHT THROUGH WEDNESDAY: THE COLD LONGWAVE TROUGH OVER
EASTERN NOAM FINALLY RETREATS NORTHWARD AND WEAKENS WITH RISING
HEIGHTS AND A FLATTENING FLOW OVER OUR REGION LASTING THROUGH MID
WEEK... AS MODIFYING SURFACE HIGH PRESSURE BUILDS IN. THE HIGH IS
INITIALLY CHILLY AND TEMPS MONDAY SHOULD RUN SEVERAL DEGREES BELOW
NORMAL... PARTICULARLY WITH MILKY SUNSHINE TO LIMIT INSOLATION AS
ONE LAST MINOR WAVE AND MID LEVEL SPEED MAX MOVE IN FROM THE WEST.
TEMPS SHOULD THEN RECOVER TO ABOVE NORMAL TUESDAY INTO WEDNESDAY AS
THE SURFACE HIGH QUICKLY MODIFIES AS IT EASES TO OUR SOUTH. THE
GFS/ECMWF BOTH SHOWS THIS HIGH PUSHING SOUTHWARD AND WEAKENING AS A
BACKDOOR FRONT APPROACHES FROM THE NORTH... ALTHOUGH THE ECMWF
SWINGS A POTENT NORTHERN STREAM WAVE THROUGH THE MIDATLANTIC
REGION... AND AS A RESULT HAS A MUCH STRONGER AND FASTER BACKDOOR
FRONT AND A NOTABLE COOLDOWN BY WEDNESDAY. WILL STAY WITH THE LESS
AMPLIFIED ROUTE OF THE GFS AT THIS TIME... AND KEEP TEMPS MILD ON
WEDNESDAY WITH FAIR SKIES. -GIH
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
AS OF 1250 AM THURSDAY...
SQUALL LINE CURRENTLY EXTENDS FROM KAVC TO KJNX TO BETWEEN KFAY AND
KCTZ...MOVING EAST AT AROUND 30 MPH. STRONGEST SOUTHERLY WINDS
CONTINUE ALONG AND AHEAD OF THE LINE WHERE 35-40KT GUSTS ARE
REPORTED. HEAVY RAIN AND A SHORT PERIOD OF IFR/LIFR VSBYS AND
CEILINGS WILL OCCUR AT KRWI BETWEEN 06Z AND 07Z. BEHIND THE
LINE...SOUTHWESTERLY WINDS WILL CONTINUE TO GUST TO 25-30KT
IMMEDIATELY BEHIND THE LINE...WITH THE STRONGEST GUSTS LIKELY TO
ACCOMPANY SCATTERED SHOWERS THROUGH 09Z.
THE MAIN COLD FRONT IS CURRENTLY CROSSING THE MOUNTAINS AND WILL
CROSS THE AREAS BY 12Z. WINDS WILL TURN TO MORE WESTERLY WITH THE
FRONT AS CEILINGS AND VSBYS RETURN TO VFR. WHILE THERE MAY BE A
WEAKENING TREND IN WINDS...EXPECT THERE WILL STILL BE SOME SPORADIC
WIND GUSTS THROUGH THE MORNING HOURS...WITH WIDESPREAD WIND GUSTS
TO 20-25KT OUT OF THE WEST DURING THE DAY.
OUTLOOK...VFR CONDITIONS ARE THEN EXPECTED TO PREVAIL THROUGH EARLY
NEXT WEEK. ALTHOUGH...A COUPLE OF COLD FRONTS WILL MOVE ACROSS THE
AREA...ONE FRIDAY MORNING AND ONE SATURDAY NIGHT AND COULD PRODUCE A
PERIOD OF INCREASED CLOUDINESS...WITH EVEN A SMALL POSSIBILITY OF
SOME SPRINKLES OR FLURRIES.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY THROUGH 4 AM EST THIS MORNING FOR
NCZ007>011-021>028-038>043-073>078-083>086-088-089.
&&
$$
SYNOPSIS...CBL/SMITH
NEAR TERM...SMITH
SHORT TERM...HARTFIELD
LONG TERM...HARTFIELD
AVIATION...KRR/SMITH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
308 AM EST THU JAN 31 2013
.SYNOPSIS...
A STRONG COLD FRONT WILL CROSS THE STATE EARLY THIS
MORNING....FOLLOWED BY COLDER AND DRIER AIR TODAY. A WEAK AND MOSTLY
DRY COLD FRONT SYSTEM WILL CROSS THE AREA EARLY FRIDAY WITH HIGH
PRESSURE BUILDING BACK IN FOR THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 255 AM THURSDAY...
...A WIND ADVISORY ALSO REMAINS IN EFFECT ACROSS ALL OF CENTRAL NC
THROUGH 4 AM LST...
SQUALL LINE HAS PUSHES EAST OF THE CWA AND TO TORNADO WATCH WAS
ALLOWED TO EXPIRE AT 2AM. WINDS IMMEDIATELY BEHIND THE LINE
CONTINUE TO GUST TO 30-35KT...BUT DIE OFF WITH WESTWARD EXTENT AWAY
FROM THE LINE. THE IS AN AREA OF STRONGER GUSTS OVER NORTHERN GA
AND WESTERN SC...BUT HRRR WIND GUST FIELDS SUGGEST THESE WINDS WILL
SHIFT EAST ACROSS SC. THUS...WE WILL ALLOW THE WIND ADVISORY TO
EXPIRE AT 4AM.
THE COLD FRONT...CURRENTLY EMERGING EAST OF THE MOUNTAINS..WILL PUSH
EAST ACROSS THE CWA THIS MORNING AND IN TO THE COASTAL PLAIN BY
12Z. EXPECT WINDS WILL GUST PERIODICALLY TO AROUND 20KT WITH THE
FRONT...THEN BECOME MORE CONSISTENT IN THE 20-25KT RANGE OUT OF THE
WEST BEHIND THE FRONT TODAY. A FEW SHOWERS ARE POSSIBLE ALONG THE
FRONT...MAINLY NORTH...AND DRYING ALOFT SHOULD LIMIT COVERAGE IN THE
SOUTH. DESPITE CLEARING BEHIND THE FRONT...MODEST COLD ADVECTION
WILL DOMINATE THE FIRST HALF OF THE DAY... KEEPING TEMPS FROM RISING
MORE THAN 4-6 DEGREES ON MOST PLACES...RANGING FROM THE MID 40S
NORTHWEST TO LOWER 50S SOUTHEAST.
ANOTHER SHORTWAVE TROUGH DIGGING SOUTHEAST OUT OF CANADA WILL SWING
ACROSS THE MID ATLANTIC STATES LATE TONIGHT. STRENGTHENING DPVA AND
A BRIEF SHOT OF 60-80M HEIGHT FALLS FOCUSED ALONG THE NC/VA BORDER
AND NORTHWARD...COMBINED WITH A BAND OF MID LEVEL MOISTURE CROSSING
THE MOUNTAINS MAY BE SUFFICIENT TO CAUSE FLURRIES...MAINLY IN THE
09-12Z TIME FRAME. THE GFS HAS THE MOST ABUNDANT MOISTURE IN
GENERAL...WITH MOISTURE REACHING TO -10C IN A BAND THAT SPANS THE
ENTIRE CWA. HOWEVER...MOISTURE WITHIN THE ICE NUCLEATION ZONE IS
ONLY PRESENT NORTH OF I-40 AND MOST PRONOUNCED NEAR THE NC/VA
BORDER. THE LIMITED DURATION OF LIFT AND MOISTURE..AS WELL AS A
RELATIVELY DRY BOUNDARY LAYER AND POTENTIAL FOR SUBLIMATION...WILL
KEEP THIS TO A NO IMPACT EVENT. LOWS IN THE UPPER 20S TO LOWER 30S.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 250 AM WEDNESDAY...
FOR FRIDAY/FRIDAY NIGHT: THE RISK OF A QUICK FLURRY OR SPRINKLE IS
LIKELY TO STRETCH PAST SUNRISE FRIDAY AS THE MID LEVEL SHORTWAVE
TROUGH SHIFTS EASTWARD OFF THE MIDATLANTIC COAST AND THE REINFORCING
CLIPPER COLD FRONT MOVES EAST OF CENTRAL NC. THE LOWEST 10 KFT LAYER
DRIES OUT RAPIDLY BY MID MORNING WITH WINDS IN THIS LAYER VEERING TO
NORTHWESTERLY AND STRONG DEEP SUBSIDENCE COMMENCING AS THE 160 KT
UPPER JET CORE SHIFTS FURTHER EAST OFF THE VA/NC COAST. EXPECT
GENERALLY CLEAR SKIES FROM LATE MORNING THROUGH THE DAY WITH A DRY
AND HIGHLY STABLE COLUMN. THE LOW LEVEL THERMAL STRUCTURE MIXING UP
TO ABOUT 800 MB SUPPORTS CHILLY HIGHS FROM 36 NORTH TO 46 NEAR THE
SC BORDER. TEMPS SHOULD DROP OFF QUICKLY AFTER SUNSET FRIDAY EVENING
THEN LEVEL OFF AS WE BEGIN TO SEE INCREASING HIGH AND MID CLOUDS
OVERNIGHT... AS MID LEVEL DPVA AND HEIGHT FALLS ARRIVE AHEAD OF THE
NEXT CLIPPER. BUT THESE CLOUDS SHOULD BE FAIRLY THIN AND GIVEN THE
VERY COLD YUKON ORIGINS OF THIS INCOMING AIR MASS AND THE WINDS
GOING NEARLY CALM AS THE SURFACE RIDGE AXIS SETTLES OVERHEAD...
STILL ANTICIPATE ABNORMALLY COLD LOWS OF 18-24.
FOR SATURDAY/SATURDAY NIGHT: THE NEXT CLIPPER FRONT WILL STRETCH
FROM THE GREAT LAKES ACROSS MO SATURDAY MORNING... WITH AN
ASSOCIATED WEAK WARM FRONT EXTENDING FROM IL TO SC. THE WARM FRONT
WILL SWEEP NORTHEASTWARD THROUGH THE NC SATURDAY AFTERNOON AS THE
SURFACE RIDGE PUSHES OFF THE COAST. CLOUD COVER WILL CONTINUE TO
THICKEN AND LOWER WITH INCREASING MID LEVEL HEIGHT FALLS IN ADVANCE
OF THE MID LEVEL SHORTWAVE TROUGH APPROACHING NC. DESPITE THE
CLOUDS... THE ENSUING SOUTHWEST LOW LEVEL FLOW SHOULD ALLOW
THICKNESSES AND TEMPS TO REBOUND TO JUST SLIGHTLY BELOW NORMAL...
HIGHS OF 45-50. MODELS DEPICT A 35-40 KT LOW LEVEL SOUTHWESTERLY JET
MOVING THROUGH THE REGION LATE SATURDAY AFTERNOON INTO THE
EVENING... COINCIDENT WITH FORECAST SOUNDINGS SHOWING DEEPENING
MOISTURE FROM 850 MB UP BEYOND 500 MB... AND AHEAD OF A MID LEVEL
VORTICITY MAX AND SHORTWAVE TROUGH THAT WILL BE TAKING ON A NEGATIVE
TILT AS IT PASSES THROUGH NC. THE SUBCLOUD LAYER SHOULD REMAIN
FAIRLY DRY HOWEVER... SO MUCH OF WHAT FALLS IS LIKELY TO
EVAPORATE/SUBLIMATE. GIVEN THAT THE WEB BULB PROFILE ON FORECAST
SOUNDINGS SHOULD BE CLOSE TO FREEZING AT THE SURFACE DURING THIS
TIME IN THE NORTHERN FORECAST AREA AND LIKELY JUST ABOVE FREEZING IN
THE SOUTH... A COMBINATION OF LIGHT SPRINKLES OR FLURRIES STILL
APPEARS REASONABLE. INTERESTING TO NOTE ARE THE GFS`S LAPSE RATES
ALOFT WHICH REACH 7.0 C/KM 800-500 MB SATURDAY NIGHT... SUGGESTING
THAT IF DYNAMIC FORCING FOR ASCENT IS STRONG ENOUGH TO AUGMENT
INSTABILITY ALOFT... WE MAY SEE A LIGHTNING STRIKE OR TWO IF THE
GFS`S STRONGER VORTICITY MAX IS CORRECT. AT ANY RATE... WILL LEAVE
IN A LOW CHANCE POP AREAWIDE FOR LATE AFTERNOON WELL INTO THE
NIGHT... BUT AGAIN EXPECT LITTLE MORE THAN TRACE TO A COUPLE OF
HUNDREDTHS OF AN INCH OF LIQUID EQUIVALENT AS THE SURFACE AIR
REMAINS DRY. SKIES SHOULD CLEAR OUT LATE SATURDAY NIGHT WITH NVA IN
THE WAKE OF THE EXITING TROUGH. LOWS 30-35. -GIH
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 150 PM WEDNESDAY...
THE WARMER START AND INCREASING SUN EXPECTED ON SUNDAY WILL ALLOW
HIGHS TO REBOUND FURTHER...INTO THE SEASONABLE LOWER 50S OVER MOST
OF THE AREA.
THE EAST COAST TROF AXIS SHIFTS OFFSHORE AND UPPER FLOW WILL NOT BE
AS AMPLIFIED EARLY NEXT WEEK. ANOTHER REINFORCING BACKDOOR COLD
FRONT WILL BE SLOWLY EDGING SOUTH AND POTENTIALLY STALLING ACROSS
THE MID ATLANTIC ON TUESDAY INTO WEDNESDAY...BUT MOISTURE WILL BE
LACKING AND FORCING WILL BE UNFOCUSED IN THE WEAKER UPPER FLOW. AT
THIS POINT THE WEATHER MONDAY THROUGH WEDNESDAY LOOKS DRY AND
SEASONABLY MILD WITH HIGHS MOSTLY IN THE LOW TO MID 50S EACH DAY.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
AS OF 1250 AM THURSDAY...
SQUALL LINE CURRENTLY EXTENDS FROM KAVC TO KJNX TO BETWEEN KFAY AND
KCTZ...MOVING EAST AT AROUND 30 MPH. STRONGEST SOUTHERLY WINDS
CONTINUE ALONG AND AHEAD OF THE LINE WHERE 35-40KT GUSTS ARE
REPORTED. HEAVY RAIN AND A SHORT PERIOD OF IFR/LIFR VSBYS AND
CEILINGS WILL OCCUR AT KRWI BETWEEN 06Z AND 07Z. BEHIND THE
LINE...SOUTHWESTERLY WINDS WILL CONTINUE TO GUST TO 25-30KT
IMMEDIATELY BEHIND THE LINE...WITH THE STRONGEST GUSTS LIKELY TO
ACCOMPANY SCATTERED SHOWERS THROUGH 09Z.
THE MAIN COLD FRONT IS CURRENTLY CROSSING THE MOUNTAINS AND WILL
CROSS THE AREAS BY 12Z. WINDS WILL TURN TO MORE WESTERLY WITH THE
FRONT AS CEILINGS AND VSBYS RETURN TO VFR. WHILE THERE MAY BE A
WEAKENING TREND IN WINDS...EXPECT THERE WILL STILL BE SOME SPORADIC
WIND GUSTS THROUGH THE MORNING HOURS...WITH WIDESPREAD WIND GUSTS
TO 20-25KT OUT OF THE WEST DURING THE DAY.
OUTLOOK...VFR CONDITIONS ARE THEN EXPECTED TO PREVAIL THROUGH EARLY
NEXT WEEK. ALTHOUGH...A COUPLE OF COLD FRONTS WILL MOVE ACROSS THE
AREA...ONE FRIDAY MORNING AND ONE SATURDAY NIGHT AND COULD PRODUCE A
PERIOD OF INCREASED CLOUDINESS...WITH EVEN A SMALL POSSIBILITY OF
SOME SPRINKLES OR FLURRIES.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY THROUGH 4 AM EST THIS MORNING FOR
NCZ007>011-021>028-038>043-073>078-083>086-088-089.
&&
$$
SYNOPSIS...CBL/SMITH
NEAR TERM...SMITH
SHORT TERM...HARTFIELD
LONG TERM...MLM
AVIATION...KRR/SMITH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
305 AM EST THU JAN 31 2013
.SYNOPSIS...
A STRONG COLD FRONT WILL CROSS THE STATE EARLY THIS
MORNING....FOLLOWED BY COLDER AND DRIER AIR TODAY. A WEAK AND MOSTLY
DRY COLD FRONT SYSTEM WILL CROSS THE AREA EARLY FRIDAY WITH HIGH
PRESSURE BUILDING BACK IN FOR THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 255 AM THURSDAY...
...A WIND ADVISORY ALSO REMAINS IN EFFECT ACROSS ALL OF CENTRAL NC
THROUGH 4 AM LST...
SQUALL LINE HAS PUSHES EAST OF THE CWA AND TO TORNADO WATCH WAS
ALLOWED TO EXPIRE AT 2AM. WINDS IMMEDIATELY BEHIND THE LINE
CONTINUE TO GUST TO 30-35KT...BUT DIE OFF WITH WESTWARD EXTENT AWAY
FROM THE LINE. THE IS AN AREA OF STRONGER GUSTS OVER NORTHERN GA
AND WESTERN SC...BUT HRRR WIND GUST FIELDS SUGGEST THESE WINDS WILL
SHIFT EAST ACROSS SC. THUS...WE WILL ALLOW THE WIND ADVISORY TO
EXPIRE AT 4AM.
THE COLD FRONT...CURRENTLY EMERGING EAST OF THE MOUNTAINS..WILL PUSH
EAST ACROSS THE CWA THIS MORNING AND IN TO THE COASTAL PLAIN BY
12Z. EXPECT WINDS WILL GUST PERIODICALLY TO AROUND 20KT WITH THE
FRONT...THEN BECOME MORE CONSISTENT IN THE 20-25KT RANGE OUT OF THE
WEST BEHIND THE FRONT TODAY. A FEW SHOWERS ARE POSSIBLE ALONG THE
FRONT...MAINLY NORTH...AND DRYING ALOFT SHOULD LIMIT COVERAGE IN THE
SOUTH. DESPITE CLEARING BEHIND THE FRONT...MODEST COLD ADVECTION
WILL DOMINATE THE FIRST HALF OF THE DAY... KEEPING TEMPS FROM RISING
MORE THAN 4-6 DEGREES ON MOST PLACES...RANGING FROM THE MID 40S
NORTHWEST TO LOWER 50S SOUTHEAST.
ANOTHER SHORTWAVE TROUGH DIGGING SOUTHEAST OUT OF CANADA WILL SWING
ACROSS THE MID ATLANTIC STATES LATE TONIGHT. STRENGTHENING DPVA AND
A BRIEF SHOT OF 60-80M HEIGHT FALLS FOCUSED ALONG THE NC/VA BORDER
AND NORTHWARD...COMBINED WITH A BAND OF MID LEVEL MOISTURE CROSSING
THE MOUNTAINS MAY BE SUFFICIENT TO CAUSE FLURRIES...MAINLY IN THE
09-12Z TIME FRAME. THE GFS HAS THE MOST ABUNDANT MOISTURE IN
GENERAL...WITH MOISTURE REACHING TO -10C IN A BAND THAT SPANS THE
ENTIRE CWA. HOWEVER...MOISTURE WITHIN THE ICE NUCLEATION ZONE IS
ONLY PRESENT NORTH OF I-40 AND MOST PRONOUNCED NEAR THE NC/VA
BORDER. THE LIMITED DURATION OF LIFT AND MOISTURE..AS WELL AS A
RELATIVELY DRY BOUNDARY LAYER AND POTENTIAL FOR SUBLIMATION...WILL
KEEP THIS TO A NO IMPACT EVENT. LOWS IN THE UPPER 20S TO LOWER 30S.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 150 PM WEDNESDAY...
COLD FRONT WILL BE WELL OFFSHORE BY DAYBREAK WITH HIGH PRESSURE
INITIALLY BUILDING ACROSS THE GULF STATES AND INTO THE REGION BEHIND
THE FRONT. MILD ORIGIN OF THE HIGH AND ENSUING WESTERLY FLOW WILL
ALLOW HIGHS ON THURSDAY TO REACH NEAR NORMAL...IN THE UPPER 40S TO
LOWER 50S AND WINDS WILL BE DIMINISHING AS THE PRESSURE GRADIENT
LOOSENS...LOOKING AT UP TO 15 MPH SUSTAINED WESTERLY WINDS WITH
GUSTS TO PERHAPS 25 MPH. A REINFORCING SHORT WAVE WILL BE DIGGING
INTO THE DOMINANT EAST COAST TROF LATE THURSDAY NIGHT...POSSIBLY
SQUEEZING OUT SOME ISOLATED FLURRIES ALONG THE NORTHWEST TIER AS IT
CROSSES THE MOUNTAINS. MINS THURSDAY NIGHT WILL BE AROUND 30...AND
THE MAIN SENSIBLE IMPACT FROM THIS SHORT WAVE WILL BE TO SHARPEN THE
NORTHWEST FLOW INTO THE TROF AND INITIATE STRONGER COLD AIR
ADVECTION ON FRIDAY...WHEN HIGHS WILL STRUGGLE TO GET OUT OF THE
30S IN THE NORTHWEST...AND MAX OUT IN THE MID 40S IN THE
SOUTHEAST. HIGH PRESSURE SETTLING OVERHEAD WILL LOCK THE COLD AIR IN
OVERNIGHT...AND UNDER CLEAR SKIES...MINS FRIDAY NIGHT WILL BOTTOM
OUT IN THE LOWER 20S.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 150 PM WEDNESDAY...
MOSTLY CLEAR SKIES WITH HIGH PRESSURE OVERHEAD SATURDAY WILL ALLOW
HIGH TEMPERATURES TO CLIMB BACK TOWARDS SEASONABLE READINGS...IN THE
45 TO 50 DEGREE RANGE. THIS HIGH WILL SHIFT QUICKLY OFFSHORE AND A
FAST MOVING MID LEVEL CLIPPER SYSTEM WILL DIG INTO THE OHIO
VALLEY ON SATURDAY NIGHT...POSSIBLY PRODUCING SOME LIGHT RAIN OR
SNOW SHOWERS AS IT TRAVERSES THE AREA...WITH LITTLE TO NO
ACCUMULATION. THE ASSOCIATED CLOUDINESS WILL PREVENT TEMPERATURES
FROM CRASHING HARD SATURDAY NIGHT...HOWEVER...WITH SUNDAY MORNING
LOWS AROUND 30. THE WARMER START AND INCREASING SUN EXPECTED ON
SUNDAY WILL ALLOW HIGHS TO REBOUND FURTHER...INTO THE SEASONABLE
LOWER 50S OVER MOST OF THE AREA.
THE EAST COAST TROF AXIS SHIFTS OFFSHORE AND UPPER FLOW WILL NOT BE
AS AMPLIFIED EARLY NEXT WEEK. ANOTHER REINFORCING BACKDOOR COLD
FRONT WILL BE SLOWLY EDGING SOUTH AND POTENTIALLY STALLING ACROSS
THE MID ATLANTIC ON TUESDAY INTO WEDNESDAY...BUT MOISTURE WILL BE
LACKING AND FORCING WILL BE UNFOCUSED IN THE WEAKER UPPER FLOW. AT
THIS POINT THE WEATHER MONDAY THROUGH WEDNESDAY LOOKS DRY AND
SEASONABLY MILD WITH HIGHS MOSTLY IN THE LOW TO MID 50S EACH DAY.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
AS OF 1250 AM THURSDAY...
SQUALL LINE CURRENTLY EXTENDS FROM KAVC TO KJNX TO BETWEEN KFAY AND
KCTZ...MOVING EAST AT AROUND 30 MPH. STRONGEST SOUTHERLY WINDS
CONTINUE ALONG AND AHEAD OF THE LINE WHERE 35-40KT GUSTS ARE
REPORTED. HEAVY RAIN AND A SHORT PERIOD OF IFR/LIFR VSBYS AND
CEILINGS WILL OCCUR AT KRWI BETWEEN 06Z AND 07Z. BEHIND THE
LINE...SOUTHWESTERLY WINDS WILL CONTINUE TO GUST TO 25-30KT
IMMEDIATELY BEHIND THE LINE...WITH THE STRONGEST GUSTS LIKELY TO
ACCOMPANY SCATTERED SHOWERS THROUGH 09Z.
THE MAIN COLD FRONT IS CURRENTLY CROSSING THE MOUNTAINS AND WILL
CROSS THE AREAS BY 12Z. WINDS WILL TURN TO MORE WESTERLY WITH THE
FRONT AS CEILINGS AND VSBYS RETURN TO VFR. WHILE THERE MAY BE A
WEAKENING TREND IN WINDS...EXPECT THERE WILL STILL BE SOME SPORADIC
WIND GUSTS THROUGH THE MORNING HOURS...WITH WIDESPREAD WIND GUSTS
TO 20-25KT OUT OF THE WEST DURING THE DAY.
OUTLOOK...VFR CONDITIONS ARE THEN EXPECTED TO PREVAIL THROUGH EARLY
NEXT WEEK. ALTHOUGH...A COUPLE OF COLD FRONTS WILL MOVE ACROSS THE
AREA...ONE FRIDAY MORNING AND ONE SATURDAY NIGHT AND COULD PRODUCE A
PERIOD OF INCREASED CLOUDINESS...WITH EVEN A SMALL POSSIBILITY OF
SOME SPRINKLES OR FLURRIES.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY THROUGH 4 AM EST THIS MORNING FOR
NCZ007>011-021>028-038>043-073>078-083>086-088-089.
&&
$$
SYNOPSIS...CBL/SMITH
NEAR TERM...SMITH
SHORT TERM...MLM
LONG TERM...MLM
AVIATION...KRR/SMITH
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
115 AM EST THU JAN 31 2013
.SYNOPSIS...
WINDY AND MILD CONDITIONS WILL CONTINUE AHEAD OF A STRONG COLD
FRONT. FAST MOVING SHOWERS AND ISOLATED THUNDERSTORMS TONIGHT
COULD PRODUCE LOCALIZED DAMAGING WIND GUSTS. DRY AND COOL
CONDITIONS WILL FOLLOW THE FRONT THURSDAY THROUGH EARLY NEXT WEEK
AS HIGH PRESSURE MOVES INTO THE REGION.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 1045 PM WEDNESDAY...TORNADO WATCH REMAINS IN EFFECT FOR THE
ENTIRE ILM CWA THRU 2 AM. MAIN ADJUSTMENT THIS UPDATE HAS BEEN
APPLIED TO THE TIMING OF THE MAIN LINE OF CONVECTION CROSSING THE
AREA. LATEST KLTX 88D TRENDS...RADAR MOSAIC OF THE SE U.S
TRENDS...AND HRRR MODEL OUTPUT...INDICATE VERY LITTLE CONVECTION TO
DEVELOP AHEAD OF THE APPROACHING LINE. THIS DUE TO A STABLE
SFC BASED MARINE LAYER HAVING PROGRESSED WELL INLAND UNDER THE
STRONG SSE-SSW LOW LEVEL WINDS. AT THIS POINT...DO NOT ANTICIPATE
ANY ROGUE CONVECTIVE CELLS WELL AHEAD OF THIS LINE. HOWEVER...THE
STRONG DYNAMICS ASSOCIATED WITH THE NEARLY SOLID LINE OF THE
CONVECTION ITSELF CONTINUES TO WARRANT THE FORECAST OF STRONG TO
SEVERE CONVECTION...WITH DAMAGING WIND GUSTS THE MAIN CONCERN.
IN ADDITION...AN ISOLATED TORNADO REMAINS POSSIBLE DUE TO
SUPPORTIVE DIRECTIONAL AND SPEED SHEAR ESPECIALLY AT THE LOWER
LEVELS. THIS ILLUSTRATED NICELY BY 00Z UPPER AIR SOUNDING
HODOGRAPHS. CONTINUED TWEAKING NEEDED FOR THE OVERNIGHT TEMP/DEWPT
TRENDS...MAINLY DEALING WITH THE POST FRONTAL AIRMASS ADVECTING
ACROSS THE FA LATE TONIGHT.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH FRIDAY NIGHT/...
AS OF 300 PM WEDNESDAY...STRONG WESTERLY WINDS WILL ADVECT MUCH
COLDER AND DRIER AIR INTO REGION BEHIND EXITING COLD FRONT LOCATED
WELL OFF THE COAST BY THURS MORNING. A VERY BROAD MID TO UPPER
TROUGH WILL SHIFT EAST THROUGH THE PERIOD FINALLY LIFTING OFF TO
THE NORTHEAST BY FRI NIGHT. AS THIS TROUGH MOVES EAST IT WILL
DRIVE A SECONDARY BOUNDARY THROUGH THE AREA BY FRI MORNING. THIS
WILL PROVIDE A REINFORCING SHOT OF COLD AND DRY AIR INTO THE AREA
AS DEEP NW FLOW SETS UP ON FRIDAY.
OVERALL A POTENT STORM SYSTEM WILL LIFT OFF TO THE NORTHEAST AS
HIGH PRESSURE RIDGES UP FROM THE GULF COAST ON THURSDAY...BUT
STRONG HIGH PRESSURE WILL BUILD DOWN FROM CANADA REACHING INTO THE
CENTRAL CONUS BY THURS NIGHT AND SHIFTING EAST OVER THE LOCAL AREA
BY LATE FRI INTO EARLY SAT. THIS WILL MAINTAIN A TIGHTENED
GRADIENT FLOW THROUGH THURS AND THEN WINDS MAY BACK SLIGHTLY
BEFORE NEXT DRY FRONTAL BOUNDARY MOVES THROUGH EARLY FRI WITH A
SPIKE UP OF WINDS BEFORE FINALLY DIMINISHING AND VEERING MORE
NORTH BY FRI NIGHT. THESE STRONG WEST TO NORTHWEST WINDS WILL
MAINTAIN CAA THROUGH MUCH OF THE PERIOD. THERE WILL ONLY BE A
BRIEF PERIOD OF MORE NEUTRAL ADVECTION AHEAD OF DRY COLD FRONT FRI
MORNING. THEREFORE 850 TEMPS DROP FROM 13C JUST AHEAD OF INITIAL
COLD FRONT EARLY THURS MORNING DOWN LESS THAN 0C BY THURS AFTN AND
THEN WILL DROP AN ADDITIONAL SEVERAL DEGREES DOWN TO -8C BY FRI
EVENING. TEMPS REACHING THE MID 50S...ALREADY 20 DEGREES COOLER
THAN ON THURS...WILL HAVE TROUBLE REACHING INTO THE 50S ON FRI AS
COLD ARCTIC HIGH PRESSURE BUILDS DOWN INTO THE AREA. OVERNIGHT
LOWS WILL DROP DOWN TOWARD FREEZING THURS NIGHT IN CAA BUT FRI
NIGHT TEMPS WILL PLUMMET ONCE WINDS DROP OFF IN THE EVENING. A
MUCH MORE IDEAL RADIATIONAL COOLING NIGHT WILL OCCUR ON FRIDAY
NIGHT AS HIGH SHIFTS OVERHEAD...MAKING FOR ONE OF THE COLDEST
NIGHTS OF THE SEASON THUS FAR...WITH WIDESPREAD READINGS IN THE
20S.
DRY AIR WILL RUN SIMILAR TO TEMPS WITH A MAJOR DROP OFF BEHIND
FIRST FRONT AND THEN A PLATEAU AND MINOR INCREASE JUST AHEAD OF
DRY POLAR COLD FRONT FRI MORNING AND THEN ANOTHER NOSE DIVE
THROUGH FRI AFTN. THE PCP WATER DROP OFF FROM 1.6 INCHES VERY
EARLY THURS MORNING DOWN TO A QUARTER OF AN INCH BY LATE THURS
MORNING AND THEN DOWN CLOSE TO A TENTH OF AN INCH BY FRI AFTN.
WITH SUCH A DRY AIR MASS IN PLACE...EXPECT SUNSHINE THROUGH MOST
OF THE PERIOD. MAY SEE SOME CLOUDS WITH LINGERING MOISTURE THROUGH
THURS MORNING AFTER RAINFALL FROM FRONT...AND A SLIGHT SPIKE AHEAD
OF FRONT FRI MORNING.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 300 PM WEDNESDAY...A RATHER REPETITIVE PATTERN FOR THE
EXTENDED AS AREAS OF HIGH PRESSURE PUSH OFFSHORE AHEAD OF A SERIES
OF WEAK COLD FRONTS.
FIRST OF THESE OCCURS SATURDAY AS DIFFUSE HIGH PRESSURE MOVES ACROSS
THE AREA AND OFFSHORE...LEAVING A BRIEF PERIOD OF MOIST RETURN FLOW
INTO THE CAROLINAS. THIS IS JUST IN ADVANCE OF A COLD FRONT WHICH
WILL CROSS THE AREA VERY EARLY SUNDAY MORNING. LIMITED FORCING
COMBINED WITH ONLY MARGINAL PWATS SUGGESTS FROPA WILL BE DRY...AND
ONLY ACT TO REINFORCE THE COOL AIR. HOWEVER...ANY WEAK CAA REMAINS
WELL DISPLACED BEHIND THE FRONT...SO SUNDAY WILL END UP BEING WARMER
THAN SATURDAY...ALTHOUGH BOTH DAYS WILL BE AROUND TO SLIGHTLY BELOW
CLIMO.
ANOTHER LARGE BUT WEAK AREA OF HIGH PRESSURE BUILDS DOWN FROM THE NW
LATE SUNDAY AND PERSISTS INTO TUESDAY WHILE SLOWLY DRIFTING ACROSS
THE REGION. THIS CONTINUES THE COOL AND DRY WEATHER WITH NEAR TO
SLIGHTLY-BELOW SEASONABLE TEMPS. THIS HIGH PRESSURE THEN DRIFTS
OFFSHORE TUESDAY AHEAD OF ANOTHER COLD FRONT PROGGED TO CROSS THE
AREA LATE IN THE DAY. GUIDANCE SHOWING CONSIDERABLE AMPLITUDE
DIFFERENCES IN THE TROUGH DRIVING THIS FRONT WHICH WILL HAVE
SIGNIFICANT IMPACT ON PRECIP POTENTIAL. FOR NOW WILL KEEP INHERITED
SCHC/SILENT POP FOR D6 SINCE BENEFICIAL CHANGES CANNOT BE MADE AT
THIS TIME. TUESDAY WILL LIKELY BE THE WARMEST DAY OF THE PERIOD
THOUGH AHEAD OF THE COLD FRONT...WITH TEMPS RETURNING TO BELOW CLIMO
FOR WEDNESDAY AS ANOTHER AREA OF HIGH PRESSURE RIDGES DOWN FROM THE
NW.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
AS OF 06Z...VFR WITH AREAS OF SHORT-LIVED MVFR/IFR AS SQUALL LINE
WITH SHOWERS/ISOLATED THUNDERSTORMS CONTINUES TO PUSH ACROSS THE
AREA OVER THE NEXT FEW HOURS. VFR EXPECTED THROUGH THE REMAINDER OF
THE VALID TAF PERIOD AFTER 10Z.
MAIN LINE OF SHOWERS IS NOW EAST OF KFLO/KLBT/KMYR...CURRENTLY
AFFECTING KCRE...AND PROGRESSING EASTWARD. EXPECT THIS ACTIVITY TO
REACH KILM WITHIN THE NEXT HOUR...BETWEEN 0645Z AND 0700Z. THIS
SQUALL LINE HAS A HISTORY OF PRODUCING STRONG WINDS WITH SUSTAINED
SPEEDS OF 20+ KTS AND GUSTS UP TO 40+ KTS...ALONG WITH SHORT-LIVED
MVFR/IFR CONDITIONS DUE TO HEAVY RAIN. WITH CURRENT TREND AND
GUIDANCE... EXPECT MAIN SQUALL LINE TO PUSH OFFSHORE BY 0715Z. AFTER
THE PASSAGE OF THE COLD FRONT...THE AREA WILL SEE A SUDDEN WIND
SHIFT...POST-FRONTAL RAIN POTENTIALLY CREATING MVFR/IFR CONDITIONS
OVER THE NEXT FEW HOURS. HAVE INCLUDED LLWS IN CURRENT FCST...AND
HAVE ISSUED AN AWW FOR KILM VALID UNTIL 0730Z FOR THE WINDSHIFT OF
60 DEGREES AND ASSOCIATED GUSTS UP TO 40+ KTS.
CLEARING SKIES WILL LEAD TO VFR CONDITIONS ACROSS THE ENTIRE AREA
BETWEEN 8-10Z. FOR THE REST OF THE PERIOD...EXPECT STRONG WESTERLY
WINDS CONTINUING THROUGH THE AFTERNOON HOURS WITH GUSTS UP TO 25
KTS. GUSTS WILL SUBSIDE INTO THE EVENING HOURS.
EXTENDED OUTLOOK...VFR THROUGH THE EXTENDED.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1045 PM WEDNESDAY...SFC PG WINDS CONTINUE TO OVERSPREAD THE
COASTAL WATERS...WITH WINDS OF 15 TO 30 KT SPEEDS ACROSS THE NEAR
SHORE WATERS DUE TO SSTS IN THE LOW 50S. ACROSS THE OUTER WATERS
OF THE ILM CWA WHERE SSTS INCREASE TO AROUND 60 DEGREES...LOOK
FOR HIGHER WIND SPEEDS OF 25 TO 40 KT. WITH THE INCREASING OF SSE-
SSW WINDS THIS EVENING. ..BUILDING SHORT PERIOD SEAS HAVE FINALLY
RESPONDED. IE. SEAS AT THE OCEAN CREST PIER HAVE NOW CLIMBED TO 7
FT...THE ONSLOW BAY AND FRYING PAN SHOALS BUOYS HAVE CLIMBED TO
12-13 FT RESPECTIVELY...WITH SSTS MEASURED AT BOTH THESE BUOYS OF
60 AND 68 DEGREES RESPECTIVELY. OVERALL...LOOK FOR THIS RANGE OF
WINDS AND SEA CONDITIONS TO PERSIST ACROSS THE FA WATERS UNTIL THE
PASSAGE OF THE COLD FRONT BETWEEN 1 AM AND 5 AM. OVERALL...BUILDING
SIGNIFICANT SEAS HAVE LEVELED OFF FOR THE REMAINDER OF THE
OVERNIGHT...WITH ADJUSTMENTS UPWARDS NEEDED FOR THURSDAY FOR THE
ILM WATERS FROM CAPE FEAR SOUTH TO MURRELLS INLET DUE TO THE
STRONG WSW-W WIND DIRECTIONS KEEPING THE SEAS AGITATED.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 300 PM WEDNESDAY...ALTHOUGH SEAS WILL BE ON THE DECREASE
THROUGH MUCH OF THE PERIOD IN STRONG OFF SHORE FLOW...TIGHTENED
GRADIENT FLOW AND COLD SURGE BEHIND FRONT THURS AND AGAIN ON FRI WILL
MAINTAIN SEAS ABOVE SCA THROUGH A GOOD PORTION OF THE SHORT TERM
PERIOD IN THE OUTER WATERS. WESTERLY WINDS UP AROUND 25 KTS WILL
DROP THROUGH THURS ALLOWING OFF SHORE SEAS TO SUBSIDE FROM 8 TO
10 FT FRI MORNING DOWN TO 5 FT BY THURS NIGHT.
WINDS WILL BACK SLIGHTLY TO THE SW THURS NIGHT INTO EARLY FRI
AHEAD OF APPROACHING DRY COLD FRONT BEFORE SPIKING UP IN SURGE
BEHIND FRONT. THIS WILL PRODUCE SEAS AROUND 6 FT ONCE AGAIN FOR A
FEW HOURS ON FRI. THE NEAR SHORE WATERS WILL DECREASE THROUGH
THURS IN OFF SHORE FLOW DOWN TO 2 TO 4 FT AND MAY SPIKE UP A BIT
FRI MORNING BUT OVERALL WILL DROP OFF SOME MORE LATE FRI AS HIGH
PRESSURE SHIFTS OVERHEAD ALLOWING FOR LOCAL SEAS TO DROP TO 2 TO 3 FT
IN ALL WATERS.
LONG TERM /SATURDAY THROUGH MONDAY/...
AS OF 300 PM WEDNESDAY...OTHER THAN A WEAK COLD FRONT
SUNDAY...DIFFUSE HIGH PRESSURE WILL DOMINATE THE WEATHER ACROSS THE
WATERS THROUGH THE EXTENDED. ONE AREA OF HIGH PRESSURE WILL MOVE
ACROSS THE WATERS SATURDAY CREATING LIGHT AND VARIABLE
WINDS...VEERING TO THE SW AND INCREASING TO AROUND 10 KTS LATE IN
THE DAY. THIS AHEAD OF A COLD FRONT WHICH WILL CROSS DURING
SUNDAY...TURNING WINDS TO THE W/NW AT 10-15 KTS ON SUNDAY BEFORE
SLOWLY EASING TO LIGHT AND VARIABLE AGAIN MONDAY AS HIGH PRESSURE
BUILDS BACK OVER THE WATERS. SEAS WILL BE PRIMARILY WIND-DRIVEN
THROUGH THE PERIOD...1-2 FT SATURDAY AND MONDAY...INCREASING FOR A
SHORT TIME SUNDAY UP TO 2-4 FT WITH A NW WIND WAVE DOMINANT.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...WIND ADVISORY UNTIL 6 AM EST EARLY THIS MORNING FOR SCZ017-023-
024-032-033-039-053>056.
NC...WIND ADVISORY UNTIL 6 AM EST EARLY THIS MORNING FOR NCZ087-096-
099-105>110.
MARINE...GALE WARNING UNTIL 6 AM EST EARLY THIS MORNING FOR AMZ250-252-
254-256.
&&
$$
SYNOPSIS...RGZ
NEAR TERM...DCH
SHORT TERM...RGZ
LONG TERM...JDW
AVIATION...SGL
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1119 PM EST WED JAN 30 2013
.SYNOPSIS...
WINDY AND MILD CONDITIONS WILL CONTINUE AHEAD OF A STRONG COLD
FRONT. FAST MOVING SHOWERS AND ISOLATED THUNDERSTORMS TONIGHT
COULD PRODUCE LOCALIZED DAMAGING WIND GUSTS. DRY AND COOL
CONDITIONS WILL FOLLOW THE FRONT THURSDAY THROUGH EARLY NEXT WEEK
AS HIGH PRESSURE MOVES INTO THE REGION.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
AS OF 1045 PM WEDNESDAY...TORNADO WATCH REMAINS IN EFFECT FOR THE
ENTIRE ILM CWA THRU 2 AM. MAIN ADJUSTMENT THIS UPDATE HAS BEEN
APPLIED TO THE TIMING OF THE MAIN LINE OF CONVECTION CROSSING THE
AREA. LATEST KLTX 88D TRENDS...RADAR MOSAIC OF THE SE U.S
TRENDS...AND HRRR MODEL OUTPUT...INDICATE VERY LITTLE CONVECTION TO
DEVELOP AHEAD OF THE APPROACHING LINE. THIS DUE TO A STABLE
SFC BASED MARINE LAYER HAVING PROGRESSED WELL INLAND UNDER THE
STRONG SSE-SSW LOW LEVEL WINDS. AT THIS POINT...DO NOT ANTICIPATE
ANY ROGUE CONVECTIVE CELLS WELL AHEAD OF THIS LINE. HOWEVER...THE
STRONG DYNAMICS ASSOCIATED WITH THE NEARLY SOLID LINE OF THE
CONVECTION ITSELF CONTINUES TO WARRANT THE FORECAST OF STRONG TO
SEVERE CONVECTION...WITH DAMAGING WIND GUSTS THE MAIN CONCERN.
IN ADDITION...AN ISOLATED TORNADO REMAINS POSSIBLE DUE TO
SUPPORTIVE DIRECTIONAL AND SPEED SHEAR ESPECIALLY AT THE LOWER
LEVELS. THIS ILLUSTRATED NICELY BY 00Z UPPER AIR SOUNDING
HODOGRAPHS. CONTINUED TWEAKING NEEDED FOR THE OVERNIGHT TEMP/DEWPT
TRENDS...MAINLY DEALING WITH THE POST FRONTAL AIRMASS ADVECTING
ACROSS THE FA LATE TONIGHT.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
AS OF 300 PM WEDNESDAY...STRONG WESTERLY WINDS WILL ADVECT MUCH
COLDER AND DRIER AIR INTO REGION BEHIND EXITING COLD FRONT LOCATED
WELL OFF THE COAST BY THURS MORNING. A VERY BROAD MID TO UPPER
TROUGH WILL SHIFT EAST THROUGH THE PERIOD FINALLY LIFTING OFF TO
THE NORTHEAST BY FRI NIGHT. AS THIS TROUGH MOVES EAST IT WILL
DRIVE A SECONDARY BOUNDARY THROUGH THE AREA BY FRI MORNING. THIS
WILL PROVIDE A REINFORCING SHOT OF COLD AND DRY AIR INTO THE AREA
AS DEEP NW FLOW SETS UP ON FRIDAY.
OVERALL A POTENT STORM SYSTEM WILL LIFT OFF TO THE NORTHEAST AS
HIGH PRESSURE RIDGES UP FROM THE GULF COAST ON THURSDAY...BUT
STRONG HIGH PRESSURE WILL BUILD DOWN FROM CANADA REACHING INTO THE
CENTRAL CONUS BY THURS NIGHT AND SHIFTING EAST OVER THE LOCAL AREA
BY LATE FRI INTO EARLY SAT. THIS WILL MAINTAIN A TIGHTENED
GRADIENT FLOW THROUGH THURS AND THEN WINDS MAY BACK SLIGHTLY
BEFORE NEXT DRY FRONTAL BOUNDARY MOVES THROUGH EARLY FRI WITH A
SPIKE UP OF WINDS BEFORE FINALLY DIMINISHING AND VEERING MORE
NORTH BY FRI NIGHT. THESE STRONG WEST TO NORTHWEST WINDS WILL
MAINTAIN CAA THROUGH MUCH OF THE PERIOD. THERE WILL ONLY BE A
BRIEF PERIOD OF MORE NEUTRAL ADVECTION AHEAD OF DRY COLD FRONT FRI
MORNING. THEREFORE 850 TEMPS DROP FROM 13C JUST AHEAD OF INITIAL
COLD FRONT EARLY THURS MORNING DOWN LESS THAN 0C BY THURS AFTN AND
THEN WILL DROP AN ADDITIONAL SEVERAL DEGREES DOWN TO -8C BY FRI
EVENING. TEMPS REACHING THE MID 50S...ALREADY 20 DEGREES COOLER
THAN ON THURS...WILL HAVE TROUBLE REACHING INTO THE 50S ON FRI AS
COLD ARCTIC HIGH PRESSURE BUILDS DOWN INTO THE AREA. OVERNIGHT
LOWS WILL DROP DOWN TOWARD FREEZING THURS NIGHT IN CAA BUT FRI
NIGHT TEMPS WILL PLUMMET ONCE WINDS DROP OFF IN THE EVENING. A
MUCH MORE IDEAL RADIATIONAL COOLING NIGHT WILL OCCUR ON FRIDAY
NIGHT AS HIGH SHIFTS OVERHEAD...MAKING FOR ONE OF THE COLDEST
NIGHTS OF THE SEASON THUS FAR...WITH WIDESPREAD READINGS IN THE
20S.
DRY AIR WILL RUN SIMILAR TO TEMPS WITH A MAJOR DROP OFF BEHIND
FIRST FRONT AND THEN A PLATEAU AND MINOR INCREASE JUST AHEAD OF
DRY POLAR COLD FRONT FRI MORNING AND THEN ANOTHER NOSE DIVE
THROUGH FRI AFTN. THE PCP WATER DROP OFF FROM 1.6 INCHES VERY
EARLY THURS MORNING DOWN TO A QUARTER OF AN INCH BY LATE THURS
MORNING AND THEN DOWN CLOSE TO A TENTH OF AN INCH BY FRI AFTN.
WITH SUCH A DRY AIR MASS IN PLACE...EXPECT SUNSHINE THROUGH MOST
OF THE PERIOD. MAY SEE SOME CLOUDS WITH LINGERING MOISTURE THROUGH
THURS MORNING AFTER RAINFALL FROM FRONT...AND A SLIGHT SPIKE AHEAD
OF FRONT FRI MORNING.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 300 PM WEDNESDAY...A RATHER REPETITIVE PATTERN FOR THE
EXTENDED AS AREAS OF HIGH PRESSURE PUSH OFFSHORE AHEAD OF A SERIES
OF WEAK COLD FRONTS.
FIRST OF THESE OCCURS SATURDAY AS DIFFUSE HIGH PRESSURE MOVES ACROSS
THE AREA AND OFFSHORE...LEAVING A BRIEF PERIOD OF MOIST RETURN FLOW
INTO THE CAROLINAS. THIS IS JUST IN ADVANCE OF A COLD FRONT WHICH
WILL CROSS THE AREA VERY EARLY SUNDAY MORNING. LIMITED FORCING
COMBINED WITH ONLY MARGINAL PWATS SUGGESTS FROPA WILL BE DRY...AND
ONLY ACT TO REINFORCE THE COOL AIR. HOWEVER...ANY WEAK CAA REMAINS
WELL DISPLACED BEHIND THE FRONT...SO SUNDAY WILL END UP BEING WARMER
THAN SATURDAY...ALTHOUGH BOTH DAYS WILL BE AROUND TO SLIGHTLY BELOW
CLIMO.
ANOTHER LARGE BUT WEAK AREA OF HIGH PRESSURE BUILDS DOWN FROM THE NW
LATE SUNDAY AND PERSISTS INTO TUESDAY WHILE SLOWLY DRIFTING ACROSS
THE REGION. THIS CONTINUES THE COOL AND DRY WEATHER WITH NEAR TO
SLIGHTLY-BELOW SEASONABLE TEMPS. THIS HIGH PRESSURE THEN DRIFTS
OFFSHORE TUESDAY AHEAD OF ANOTHER COLD FRONT PROGGED TO CROSS THE
AREA LATE IN THE DAY. GUIDANCE SHOWING CONSIDERABLE AMPLITUDE
DIFFERENCES IN THE TROUGH DRIVING THIS FRONT WHICH WILL HAVE
SIGNIFICANT IMPACT ON PRECIP POTENTIAL. FOR NOW WILL KEEP INHERITED
SCHC/SILENT POP FOR D6 SINCE BENEFICIAL CHANGES CANNOT BE MADE AT
THIS TIME. TUESDAY WILL LIKELY BE THE WARMEST DAY OF THE PERIOD
THOUGH AHEAD OF THE COLD FRONT...WITH TEMPS RETURNING TO BELOW CLIMO
FOR WEDNESDAY AS ANOTHER AREA OF HIGH PRESSURE RIDGES DOWN FROM THE
NW.
&&
.AVIATION /04Z THURSDAY THROUGH MONDAY/...
AS OF 00Z...STRONG COLD FRONT TO IMPACT THE TERMINALS TONIGHT WITH
GUSTY WINDS AND A POTENTIAL SQUALL LINE WITH SHOWERS/ISOLATED
THUNDERSTORMS.
COLD FRONT CURRENTLY ACROSS WESTERN PORTIONS OF SC/NC WILL PUSH EAST
TONIGHT AND BE ACCOMPANIED BY A LINE OF SHOWERS WITH ISOLATED
THUNDERSTORMS. HRRR APPEARS TO BE INITIALIZING BETTER THAN ANY OF
THE OTHER HIGH-RES GUIDANCE...SO HAVE RELIED HEAVILY ON THIS MODEL
FOR TIMING CONVECTION AT THE TERMINALS...AND EXPECT THE SQUALL LINE
TO IMPACT FLO/LBT AROUND 03Z...RACING EAST TO ILM AROUND 06Z.
ATTM...NO IFR HAS BEEN INTRODUCED INTO THE CURRENT SET OF TAFS DUE
TO UNCERTAINTY IN EXACT TIMING AND LIKELY SHORT-DURATION OF ANY
PRECIP INDUCED IFR. PREFER TO HANDLE ANY IFR WITH AMD/TEMPO GROUPS
AS THE CONVECTION UNFOLDS. HAVE SHOWN A 2-HR TEMPO GROUP AT ALL
TERMINALS FOR THE HEAVIEST CONVECTION WITH MVFR AND INCREASED WIND
GUSTS...BUT STRONGER GUSTS ARE POSSIBLE THAN WHAT IS CURRENTLY
DEPICTED.
OTHER CONCERN IS THE STRONG PRE-FRONTAL AND POST-FRONTAL WINDS. S/SW
WINDS WILL CONTINUE TO INCREASE TONIGHT AS A STRENGTHENING LOW LEVEL
JET MOVES OVERHEAD. FOR THIS REASON HAVE SHOWN INCREASING LLWS IN
ALL TAFS WITH 30 KT GUSTS LIKELY THROUGH THE NIGHT...EVEN OUTSIDE OF
CONVECTION. A SUDDEN WIND SHIFT WILL OCCUR WITH THE FROPA
TONIGHT...AND AWWS MAY BE REQUIRED FOR ILM/MYR LATER TONIGHT AS THE
FRONT CROSSES...AND WINDS SHIFT SUDDENLY TO THE WEST.
RAPID DRYING OCCURS BEHIND THE FRONT AND SKC WILL BECOME THE SKY
CONDITION ON THURSDAY. ALTHOUGH IT WILL BE CLEAR...STRONG WESTERLY
WINDS WILL PERSIST THROUGH THE DAY...GUSTING TO 25 KTS THROUGH THE
END OF THE VALID PERIOD.
EXTENDED OUTLOOK...VFR THROUGH THE EXTENDED.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1045 PM WEDNESDAY...SFC PG WINDS CONTINUE TO OVERSPREAD THE
COASTAL WATERS...WITH WINDS OF 15 TO 30 KT SPEEDS ACROSS THE NEAR
SHORE WATERS DUE TO SSTS IN THE LOW 50S. ACROSS THE OUTER WATERS
OF THE ILM CWA WHERE SSTS INCREASE TO AROUND 60 DEGREES...LOOK
FOR HIGHER WIND SPEEDS OF 25 TO 40 KT. WITH THE INCREASING OF SSE-
SSW WINDS THIS EVENING. ..BUILDING SHORT PERIOD SEAS HAVE FINALLY
RESPONDED. IE. SEAS AT THE OCEAN CREST PIER HAVE NOW CLIMBED TO 7
FT...THE ONSLOW BAY AND FRYING PAN SHOALS BUOYS HAVE CLIMBED TO
12-13 FT RESPECTIVELY...WITH SSTS MEASURED AT BOTH THESE BUOYS OF
60 AND 68 DEGREES RESPECTIVELY. OVERALL...LOOK FOR THIS RANGE OF
WINDS AND SEA CONDITIONS TO PERSIST ACROSS THE FA WATERS UNTIL THE
PASSAGE OF THE COLD FRONT BETWEEN 1 AM AND 5 AM. OVERALL...BUILDING
SIGNIFICANT SEAS HAVE LEVELED OFF FOR THE REMAINDER OF THE
OVERNIGHT...WITH ADJUSTMENTS UPWARDS NEEDED FOR THURSDAY FOR THE
ILM WATERS FROM CAPE FEAR SOUTH TO MURRELLS INLET DUE TO THE
STRONG WSW-W WIND DIRECTIONS KEEPING THE SEAS AGITATED.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 300 PM WEDNESDAY...ALTHOUGH SEAS WILL BE ON THE DECREASE
THROUGH MUCH OF THE PERIOD IN STRONG OFF SHORE FLOW...TIGHTENED
GRADIENT FLOW AND COLD SURGE BEHIND FRONT THURS AND AGAIN ON FRI WILL
MAINTAIN SEAS ABOVE SCA THROUGH A GOOD PORTION OF THE SHORT TERM
PERIOD IN THE OUTER WATERS. WESTERLY WINDS UP AROUND 25 KTS WILL
DROP THROUGH THURS ALLOWING OFF SHORE SEAS TO SUBSIDE FROM 8 TO
10 FT FRI MORNING DOWN TO 5 FT BY THURS NIGHT.
WINDS WILL BACK SLIGHTLY TO THE SW THURS NIGHT INTO EARLY FRI
AHEAD OF APPROACHING DRY COLD FRONT BEFORE SPIKING UP IN SURGE
BEHIND FRONT. THIS WILL PRODUCE SEAS AROUND 6 FT ONCE AGAIN FOR A
FEW HOURS ON FRI. THE NEAR SHORE WATERS WILL DECREASE THROUGH
THURS IN OFF SHORE FLOW DOWN TO 2 TO 4 FT AND MAY SPIKE UP A BIT
FRI MORNING BUT OVERALL WILL DROP OFF SOME MORE LATE FRI AS HIGH
PRESSURE SHIFTS OVERHEAD ALLOWING FOR LOCAL SEAS TO DROP TO 2 TO 3 FT
IN ALL WATERS.
LONG TERM /SATURDAY THROUGH MONDAY/...
AS OF 300 PM WEDNESDAY...OTHER THAN A WEAK COLD FRONT
SUNDAY...DIFFUSE HIGH PRESSURE WILL DOMINATE THE WEATHER ACROSS THE
WATERS THROUGH THE EXTENDED. ONE AREA OF HIGH PRESSURE WILL MOVE
ACROSS THE WATERS SATURDAY CREATING LIGHT AND VARIABLE
WINDS...VEERING TO THE SW AND INCREASING TO AROUND 10 KTS LATE IN
THE DAY. THIS AHEAD OF A COLD FRONT WHICH WILL CROSS DURING
SUNDAY...TURNING WINDS TO THE W/NW AT 10-15 KTS ON SUNDAY BEFORE
SLOWLY EASING TO LIGHT AND VARIABLE AGAIN MONDAY AS HIGH PRESSURE
BUILDS BACK OVER THE WATERS. SEAS WILL BE PRIMARILY WIND-DRIVEN
THROUGH THE PERIOD...1-2 FT SATURDAY AND MONDAY...INCREASING FOR A
SHORT TIME SUNDAY UP TO 2-4 FT WITH A NW WIND WAVE DOMINANT.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...WIND ADVISORY UNTIL 6 AM EST THURSDAY FOR SCZ017-023-024-032-
033-039-053>056.
NC...WIND ADVISORY UNTIL 6 AM EST THURSDAY FOR NCZ087-096-099-
105>110.
MARINE...GALE WARNING UNTIL 6 AM EST THURSDAY FOR AMZ250-252-254-256.
&&
$$
SYNOPSIS...RGZ
NEAR TERM...DCH
SHORT TERM...RGZ
LONG TERM...JDW
AVIATION...JDW/SGL
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
937 PM EST WED JAN 30 2013
.SYNOPSIS...
WINDY AND MILD CONDITIONS WILL CONTINUE AHEAD OF A STRONG COLD
FRONT. FAST MOVING SHOWERS AND ISOLATED THUNDERSTORMS TONIGHT
COULD PRODUCE LOCALIZED DAMAGING WIND GUSTS. DRY AND COOL
CONDITIONS WILL FOLLOW THE FRONT THURSDAY THROUGH EARLY NEXT WEEK
AS HIGH PRESSURE MOVES INTO THE REGION.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
AS OF 845 PM WEDNESDAY...MAIN ADJUSTMENT ASSOCIATED WITH THE
TORNADO WATCH IN EFFECT FOR THE ENTIRE ILM CWA THRU 2 AM. IN
ADDITION...ADJUSTMENTS TO THE TIMING...OF THE APPROACH AND
DEPARTURE OF THE MAIN LINE OF CONVECTION HAS ALSO BEEN APPLIED.
LATEST 88D MOSAIC INDICATES VERY LITTLE CONVECTION DEVELOPING
AHEAD OF THE APPROACHING LINE...MAINLY DUE TO A STABLE MARINE SFC
BASED LAYER HAVING PROGRESSED WELL INLAND UNDER THE STRONG SSE-
SSW LOW LEVEL WINDS. AT THIS POINT...DO NOT ANTICIPATE THOSE ROGUE
CONVECTIVE CELLS WELL AHEAD OF THIS LINE. HOWEVER...THE STRONG
DYNAMICS ASSOCIATED WITH THE NEARLY SOLID LINE OF CONVECTION
ITSELF CONTINUES TO WARRANT THE FORECAST OF STRONG TO SEVERE
CONVECTION WITH DAMAGING WIND GUSTS...AND POSSIBLY A TORNADO DUE
TO SUPPORTIVE DIRECTIONAL AND SPEED SHEAR. THIS ILLUSTRATED WELL BY
00Z UPPER AIR SOUNDING HODOGRAPHS. OVERNIGHT TEMP/DEWPT ONLY NEEDED
TWEAKING WITH CURRENT VALUES APPLIED TO THE OVERNIGHT TEMP/DEWPT
TRENDS.
PREVIOUS DISCUSSION.................................................
AS OF 300 PM WEDNESDAY...THE STRONG COLD FRONT EXTENDS FROM EASTERN
TENNESSEE TO THE FLORIDA PANHANDLE AND IS CATCHING UP QUITE RAPIDLY
WITH THE PREFRONTAL SQUALL LINE. ALTHOUGH THERE ARE STILL SOME
TIMING DIFFERENCES AMONG THE VARIOUS 12Z MODELS...THE CONSENSUS IS
FOR THE FRONT TO ARRIVE IN THE SC PEE DEE REGION JUST BEFORE
MIDNIGHT...MOVING THROUGH THE GRAND STRAND AND ELIZABETHTOWN/
WHITEVILLE AREAS AROUND MIDNIGHT...THEN THROUGH WILMINGTON AND THE
CAPE FEAR COAST AROUND 1 AM. THIS WILL BE A VERY QUICK EVENT FOR ANY
ONE LOCATION AND THE SQUALL LINE SHOULD TRAVERSE OUR ENTIRE FORECAST
AREA IN 3 HOURS OR LESS.
STRONG SOUTH WINDS OUT AHEAD OF THE FRONT/SQUALL LINE HAVE GUSTED TO
39 MPH IN FLORENCE AND 36 MPH IN WILMINGTON. GUSTS OVER 40 MPH
SHOULD DEVELOP BEFORE SUNSET AS STRONGER WINDS IN THE 1000-2000 FT
LAYER GET ENTRAINED IN TURBULENT MIXING THROUGHOUT THE DAYTIME
BOUNDARY LAYER. AS THE SURFACE COOLS DOWN TO 68-70 DEGREES THIS
EVENING AND THE BOUNDARY LAYER FLATTENS TO ONLY A FEW HUNDRED FEET
THICK...WINDS AS LOW AS 1000 FT AGL WILL INCREASE TO 40-50 KNOTS.
SOME OF THIS MOMENTUM MAY STILL TUMBLE DOWN TO THE SURFACE WITH
GUSTS UP 45 MPH EXPECTED.
A SQUALL LINE CONSISTING OF LINEAR FORCED CONVECTION WITHIN A REGION
OF HIGHLY CONVERGENT LOW-LEVEL FLOW JUST AHEAD OF THE FRONT WILL BE
CAPABLE OF PRODUCING DAMAGING WIND GUSTS VIA HEAVY RAINFALL
TRANSPORTING STRONG WINDS DOWN FROM ALOFT. CONVECTIVE CELLS...
ASSUMING A 15000 FT CELL DEPTH AND MOVEMENT AT 70% OF THE MEAN
FLOW...COULD MOVE AS QUICKLY AS 65 KNOTS. THE POTENTIAL FOR
WIDESPREAD DAMAGING WINDS DOES EXIST. ASSUMING SURFACE TEMPS OF
68-70 DEGREES AND SURFACE DEWPOINTS IN THE LOWER 60S...SURFACE-BASED
CAPE SHOULD REMAIN NEAR ZERO TONIGHT. HOWEVER THE SURFACE-BASED
INVERSION WILL ALSO BE WEAK AND MAY NOT PROVIDE AN EFFECTIVE BARRIER
TO STRONG WINDS PUNCHING DOWN FROM ALOFT.
THE BEST POTENTIAL FOR SEVERE WEATHER SHOULD BE NEAR AND WEST OF
I-95...BUT EVEN AT THE COAST THE THREAT IS STILL LARGE ENOUGH FOR
CONCERN. SEVERE THUNDERSTORM WATCHES WILL PROBABLY BE NEEDED FOR THE
AREA TONIGHT. THANKFULLY...THE SHALLOW DEPTH OF THE CONVECTION PLUS
WEAK UPDRAFT STRENGTH SHOULD PRECLUDE ANY HAIL THREAT.
AFTER THE FRONT SLIDES OFFSHORE...MUCH DRIER COOLER AIR WILL BUILD
IN WITH CLEARING SKIES. LOWS SHOULD RANGE FROM 45-50.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
AS OF 300 PM WEDNESDAY...STRONG WESTERLY WINDS WILL ADVECT MUCH
COLDER AND DRIER AIR INTO REGION BEHIND EXITING COLD FRONT LOCATED
WELL OFF THE COAST BY THURS MORNING. A VERY BROAD MID TO UPPER
TROUGH WILL SHIFT EAST THROUGH THE PERIOD FINALLY LIFTING OFF TO
THE NORTHEAST BY FRI NIGHT. AS THIS TROUGH MOVES EAST IT WILL
DRIVE A SECONDARY BOUNDARY THROUGH THE AREA BY FRI MORNING. THIS
WILL PROVIDE A REINFORCING SHOT OF COLD AND DRY AIR INTO THE AREA
AS DEEP NW FLOW SETS UP ON FRIDAY.
OVERALL A POTENT STORM SYSTEM WILL LIFT OFF TO THE NORTHEAST AS
HIGH PRESSURE RIDGES UP FROM THE GULF COAST ON THURSDAY...BUT
STRONG HIGH PRESSURE WILL BUILD DOWN FROM CANADA REACHING INTO THE
CENTRAL CONUS BY THURS NIGHT AND SHIFTING EAST OVER THE LOCAL AREA
BY LATE FRI INTO EARLY SAT. THIS WILL MAINTAIN A TIGHTENED
GRADIENT FLOW THROUGH THURS AND THEN WINDS MAY BACK SLIGHTLY
BEFORE NEXT DRY FRONTAL BOUNDARY MOVES THROUGH EARLY FRI WITH A
SPIKE UP OF WINDS BEFORE FINALLY DIMINISHING AND VEERING MORE
NORTH BY FRI NIGHT. THESE STRONG WEST TO NORTHWEST WINDS WILL
MAINTAIN CAA THROUGH MUCH OF THE PERIOD. THERE WILL ONLY BE A
BRIEF PERIOD OF MORE NEUTRAL ADVECTION AHEAD OF DRY COLD FRONT FRI
MORNING. THEREFORE 850 TEMPS DROP FROM 13C JUST AHEAD OF INITIAL
COLD FRONT EARLY THURS MORNING DOWN LESS THAN 0C BY THURS AFTN AND
THEN WILL DROP AN ADDITIONAL SEVERAL DEGREES DOWN TO -8C BY FRI
EVENING. TEMPS REACHING THE MID 50S...ALREADY 20 DEGREES COOLER
THAN ON THURS...WILL HAVE TROUBLE REACHING INTO THE 50S ON FRI AS
COLD ARCTIC HIGH PRESSURE BUILDS DOWN INTO THE AREA. OVERNIGHT
LOWS WILL DROP DOWN TOWARD FREEZING THURS NIGHT IN CAA BUT FRI
NIGHT TEMPS WILL PLUMMET ONCE WINDS DROP OFF IN THE EVENING. A
MUCH MORE IDEAL RADIATIONAL COOLING NIGHT WILL OCCUR ON FRIDAY
NIGHT AS HIGH SHIFTS OVERHEAD...MAKING FOR ONE OF THE COLDEST
NIGHTS OF THE SEASON THUS FAR...WITH WIDESPREAD READINGS IN THE
20S.
DRY AIR WILL RUN SIMILAR TO TEMPS WITH A MAJOR DROP OFF BEHIND
FIRST FRONT AND THEN A PLATEAU AND MINOR INCREASE JUST AHEAD OF
DRY POLAR COLD FRONT FRI MORNING AND THEN ANOTHER NOSE DIVE
THROUGH FRI AFTN. THE PCP WATER DROP OFF FROM 1.6 INCHES VERY
EARLY THURS MORNING DOWN TO A QUARTER OF AN INCH BY LATE THURS
MORNING AND THEN DOWN CLOSE TO A TENTH OF AN INCH BY FRI AFTN.
WITH SUCH A DRY AIR MASS IN PLACE...EXPECT SUNSHINE THROUGH MOST
OF THE PERIOD. MAY SEE SOME CLOUDS WITH LINGERING MOISTURE THROUGH
THURS MORNING AFTER RAINFALL FROM FRONT...AND A SLIGHT SPIKE AHEAD
OF FRONT FRI MORNING.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 300 PM WEDNESDAY...A RATHER REPETITIVE PATTERN FOR THE
EXTENDED AS AREAS OF HIGH PRESSURE PUSH OFFSHORE AHEAD OF A SERIES
OF WEAK COLD FRONTS.
FIRST OF THESE OCCURS SATURDAY AS DIFFUSE HIGH PRESSURE MOVES ACROSS
THE AREA AND OFFSHORE...LEAVING A BRIEF PERIOD OF MOIST RETURN FLOW
INTO THE CAROLINAS. THIS IS JUST IN ADVANCE OF A COLD FRONT WHICH
WILL CROSS THE AREA VERY EARLY SUNDAY MORNING. LIMITED FORCING
COMBINED WITH ONLY MARGINAL PWATS SUGGESTS FROPA WILL BE DRY...AND
ONLY ACT TO REINFORCE THE COOL AIR. HOWEVER...ANY WEAK CAA REMAINS
WELL DISPLACED BEHIND THE FRONT...SO SUNDAY WILL END UP BEING WARMER
THAN SATURDAY...ALTHOUGH BOTH DAYS WILL BE AROUND TO SLIGHTLY BELOW
CLIMO.
ANOTHER LARGE BUT WEAK AREA OF HIGH PRESSURE BUILDS DOWN FROM THE NW
LATE SUNDAY AND PERSISTS INTO TUESDAY WHILE SLOWLY DRIFTING ACROSS
THE REGION. THIS CONTINUES THE COOL AND DRY WEATHER WITH NEAR TO
SLIGHTLY-BELOW SEASONABLE TEMPS. THIS HIGH PRESSURE THEN DRIFTS
OFFSHORE TUESDAY AHEAD OF ANOTHER COLD FRONT PROGGED TO CROSS THE
AREA LATE IN THE DAY. GUIDANCE SHOWING CONSIDERABLE AMPLITUDE
DIFFERENCES IN THE TROUGH DRIVING THIS FRONT WHICH WILL HAVE
SIGNIFICANT IMPACT ON PRECIP POTENTIAL. FOR NOW WILL KEEP INHERITED
SCHC/SILENT POP FOR D6 SINCE BENEFICIAL CHANGES CANNOT BE MADE AT
THIS TIME. TUESDAY WILL LIKELY BE THE WARMEST DAY OF THE PERIOD
THOUGH AHEAD OF THE COLD FRONT...WITH TEMPS RETURNING TO BELOW CLIMO
FOR WEDNESDAY AS ANOTHER AREA OF HIGH PRESSURE RIDGES DOWN FROM THE
NW.
&&
.AVIATION /01Z THURSDAY THROUGH MONDAY/...
AS OF 00Z...STRONG COLD FRONT TO IMPACT THE TERMINALS TONIGHT WITH
GUSTY WINDS AND A POTENTIAL SQUALL LINE WITH SHOWERS/ISOLATED
THUNDERSTORMS.
COLD FRONT CURRENTLY ACROSS WESTERN PORTIONS OF SC/NC WILL PUSH EAST
TONIGHT AND BE ACCOMPANIED BY A LINE OF SHOWERS WITH ISOLATED
THUNDERSTORMS. HRRR APPEARS TO BE INITIALIZING BETTER THAN ANY OF
THE OTHER HIGH-RES GUIDANCE...SO HAVE RELIED HEAVILY ON THIS MODEL
FOR TIMING CONVECTION AT THE TERMINALS...AND EXPECT THE SQUALL LINE
TO IMPACT FLO/LBT AROUND 03Z...RACING EAST TO ILM AROUND 06Z.
ATTM...NO IFR HAS BEEN INTRODUCED INTO THE CURRENT SET OF TAFS DUE
TO UNCERTAINTY IN EXACT TIMING AND LIKELY SHORT-DURATION OF ANY
PRECIP INDUCED IFR. PREFER TO HANDLE ANY IFR WITH AMD/TEMPO GROUPS
AS THE CONVECTION UNFOLDS. HAVE SHOWN A 2-HR TEMPO GROUP AT ALL
TERMINALS FOR THE HEAVIEST CONVECTION WITH MVFR AND INCREASED WIND
GUSTS...BUT STRONGER GUSTS ARE POSSIBLE THAN WHAT IS CURRENTLY
DEPICTED.
OTHER CONCERN IS THE STRONG PRE-FRONTAL AND POST-FRONTAL WINDS. S/SW
WINDS WILL CONTINUE TO INCREASE TONIGHT AS A STRENGTHENING LOW LEVEL
JET MOVES OVERHEAD. FOR THIS REASON HAVE SHOWN INCREASING LLWS IN
ALL TAFS WITH 30 KT GUSTS LIKELY THROUGH THE NIGHT...EVEN OUTSIDE OF
CONVECTION. A SUDDEN WIND SHIFT WILL OCCUR WITH THE FROPA
TONIGHT...AND AWWS MAY BE REQUIRED FOR ILM/MYR LATER TONIGHT AS THE
FRONT CROSSES...AND WINDS SHIFT SUDDENLY TO THE WEST.
RAPID DRYING OCCURS BEHIND THE FRONT AND SKC WILL BECOME THE SKY
CONDITION ON THURSDAY. ALTHOUGH IT WILL BE CLEAR...STRONG WESTERLY
WINDS WILL PERSIST THROUGH THE DAY...GUSTING TO 25 KTS THROUGH THE
END OF THE VALID PERIOD.
EXTENDED OUTLOOK...VFR THROUGH THE EXTENDED.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 845 PM WEDNESDAY...SFC PG WINDS HAVE FINALLY REACHED THE
COASTAL WATERS...WITH 15 TO 30 KT SUSTAINED SPEEDS WITH ASSOCIATED
GUSTS FROM 25 TO 40 KT. THE HIER SPEEDS WILL OCCUR ACROSS THE
OUTER WATERS OF THE ILM COASTAL WATERS...AND WHERE SSTS ARE 60
DEGREES AND HIGHER. WITH INCREASING SSE-SSW WINDS THIS AFTERNOON
AND ESPECIALLY THIS EVENING...SEAS HAVE FINALLY RESPONDED. IE.
SEAS AT THE OCEAN CREST PIER HAVE CLIMBED TO 6 FT AS OF THIS
WRITING. OVERALL...LOOK FOR THESE WIND AND RESULTING SEA
CONDITIONS TO PERSIST UNTIL THE CFP...SLATED BETWEEN 1 AM TO 4 AM
WHEN THE CF TRACKS WEST TO EAST ACROSS THE ILM WATERS. OVERALL
SEAS HAVE BEEN ADJUSTED UPWARDS OVERNIGHT INTO MUCH OF THE DAY ON
THURSDAY. THE LATTER WAS ADJUSTED MAINLY FOR THE ILM WATERS FROM
CAPE FEAR SOUTH TO MURRELLS INLET DUE TO THE STRONG WSW-W WIND
DIRECTIONS KEEPING THE SEAS AGITATED.
PREVIOUS DISCUSSION...............................................
AS OF 300 PM WEDNESDAY...SOUTH WINDS WILL INCREASE THROUGH THE
EVENING AHEAD OF A STRONG COLD FRONT NOW LOCATED FROM EASTERN
TENNESSEE SOUTH TO THE FLORIDA PANHANDLE. ALTHOUGH WINDS ARE
CURRENTLY ONLY 20-30 KNOTS ACROSS THE COASTAL WATERS...A 3-4 HOUR
PERIOD OF MUCH STRONGER WINDS IS EXPECTED TO DEVELOP JUST AHEAD OF
THE FRONT THIS EVENING. 35-40 KNOT WINDS MAY GUST MUCH HIGHER AS A
NARROW LINE OF SHOWERS AND EMBEDDED THUNDERSTORMS PUSH OFFSHORE
JUST AFTER MIDNIGHT. A SEVERE THUNDERSTORM WATCH PROBABLY WILL BE
NEEDED TO ADDRESS THIS POTENTIAL. BEHIND THE FRONT...WINDS WILL
TURN WESTERLY IN THE 25-35 KNOT RANGE THROUGH DAYBREAK. SEAS
CURRENTLY 4-7 FT WILL BUILD THIS EVENING TO 8-12 FEET AWAY FROM
SHORE WITH THE STRONG SOUTH WINDS.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 300 PM WEDNESDAY...ALTHOUGH SEAS WILL BE ON THE DECREASE
THROUGH MUCH OF THE PERIOD IN STRONG OFF SHORE FLOW...TIGHTENED
GRADIENT FLOW AND COLD SURGE BEHIND FRONT THURS AND AGAIN ON FRI WILL
MAINTAIN SEAS ABOVE SCA THROUGH A GOOD PORTION OF THE SHORT TERM
PERIOD IN THE OUTER WATERS. WESTERLY WINDS UP AROUND 25 KTS WILL
DROP THROUGH THURS ALLOWING OFF SHORE SEAS TO SUBSIDE FROM 8 TO
10 FT FRI MORNING DOWN TO 5 FT BY THURS NIGHT.
WINDS WILL BACK SLIGHTLY TO THE SW THURS NIGHT INTO EARLY FRI
AHEAD OF APPROACHING DRY COLD FRONT BEFORE SPIKING UP IN SURGE
BEHIND FRONT. THIS WILL PRODUCE SEAS AROUND 6 FT ONCE AGAIN FOR A
FEW HOURS ON FRI. THE NEAR SHORE WATERS WILL DECREASE THROUGH
THURS IN OFF SHORE FLOW DOWN TO 2 TO 4 FT AND MAY SPIKE UP A BIT
FRI MORNING BUT OVERALL WILL DROP OFF SOME MORE LATE FRI AS HIGH
PRESSURE SHIFTS OVERHEAD ALLOWING FOR LOCAL SEAS TO DROP TO 2 TO 3 FT
IN ALL WATERS.
LONG TERM /SATURDAY THROUGH MONDAY/...
AS OF 300 PM WEDNESDAY...OTHER THAN A WEAK COLD FRONT
SUNDAY...DIFFUSE HIGH PRESSURE WILL DOMINATE THE WEATHER ACROSS THE
WATERS THROUGH THE EXTENDED. ONE AREA OF HIGH PRESSURE WILL MOVE
ACROSS THE WATERS SATURDAY CREATING LIGHT AND VARIABLE
WINDS...VEERING TO THE SW AND INCREASING TO AROUND 10 KTS LATE IN
THE DAY. THIS AHEAD OF A COLD FRONT WHICH WILL CROSS DURING
SUNDAY...TURNING WINDS TO THE W/NW AT 10-15 KTS ON SUNDAY BEFORE
SLOWLY EASING TO LIGHT AND VARIABLE AGAIN MONDAY AS HIGH PRESSURE
BUILDS BACK OVER THE WATERS. SEAS WILL BE PRIMARILY WIND-DRIVEN
THROUGH THE PERIOD...1-2 FT SATURDAY AND MONDAY...INCREASING FOR A
SHORT TIME SUNDAY UP TO 2-4 FT WITH A NW WIND WAVE DOMINANT.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...WIND ADVISORY UNTIL 6 AM EST THURSDAY FOR SCZ017-023-024-032-
033-039-053>056.
NC...WIND ADVISORY UNTIL 6 AM EST THURSDAY FOR NCZ087-096-099-
105>110.
MARINE...GALE WARNING UNTIL 6 AM EST THURSDAY FOR AMZ250-252-254-256.
&&
$$
SYNOPSIS...RGZ
NEAR TERM...DCH/TRA
SHORT TERM...RGZ
LONG TERM...JDW
AVIATION...JDW
AREA FORECAST DISCUSSION
NWS ALBANY NY
415 PM EST THU JAN 31 2013
.SYNOPSIS...
S A CANADIAN AIR MASS MOVES INTO THE REGION...
TEMPERATURES WILL BE MUCH COLDER TONIGHT WITH A DIMINISHING WIND.
LAKE EFFECT SNOW SHOWERS WILL CONTINUE TO AFFECT THE WESTERN
ADIRONDACKS AND MOHAWK VALLEY OVERNIGHT. LAKE EFFECT SNOW WILL SHIFT
SOUTH AND WEST OF THE REGION TOMORROW...WITH COLD TEMPERATURES AND
BREEZY CONDITIONS. SEASONABLY CHILLY TEMPERATURES WILL CONTINUE TO
BE IN PLACE OVER THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
AS OF 415 PM EST...WINDS ARE STARTING TO DIMINISH AS THE PRESSURE
GRADIENT BEGINS TO RELAX. THE PRESSURE COUPLET ASSOCIATED WITH THE
SFC FRONTAL BOUNDARY IS WELL NORTHEAST OF THE REGION ACROSS
ATLANTIC CANADA. STILL...A FEW GUSTS OF 25-40 MPH ARE OCCURRING
LATE THIS AFTN...SO WE WILL LET THE CURRENT HIGH WIND WARNING
EXPIRE AT 6 PM. BY THAT POINT...WINDS WILL STILL BE BREEZY FOR THE
OVERNIGHT HOURS...BUT NOT ENOUGH TO CAUSE DAMAGE.
A BAND OF LAKE EFFECT SNOW IS CURRENTLY ONGOING ACROSS THE WESTERN
ADIRONDACKS. THE LOCAL HIRES WRF MODEL...AS WELL AS THE NAM12 AND
3KM HRRR MODEL...SHOWS THIS BAND TO SHIFT SOUTHWARD DURING THE
OVERNIGHT HOURS. WITH THIS BAND HAVING AN EXCELLENT MULTI-LAKE
CONNECTION ALL THE WAY BACK TO THE WESTERN GREAT LAKES AND STRONG
LOW LEVEL SPEED SHEAR...LOCAL CSTAR RESEARCH WOULD SUGGEST THAT
THIS BAND REACHES WELL INTO OUR AREA. AS A RESULT...HAVE ALSO
INCLUDED A LAKE EFFECT SNOW ADVISORY FOR HAMILTON COUNTY...IN
ADDITION TO THE WSW ALREADY IN EFFECT FOR NRN HERKIMER. SNOW
TOTALS LOOK TO REACH 4-8 INCHES IN NRN HERKIMER AND 3-6 INCHES
ACROSS WESTERN HAMILTON COUNTY.
AS THE BAND SHIFTS SOUTH FOR LATE TONIGHT...IT SHOULD MOVE
QUICKLY. WHILE A QUICK FEW INCHES OF ACCUMULATION IS POSSIBLE
ACROSS THE MOHAWK VALLEY...IT SHOULD MOVE QUICK ENOUGH SOUTHWARD TO
PREVENT ANY MODERATE ACCUMULATION OF SNOW. AS A RESULT...WE WILL
NOT ISSUE ANY LAKE EFFECT ADVISORIES FOR THE MOHAWK VALLEY
AREA...BUT WILL CONTINUE TO MENTION IN OUR HWO STATEMENT.
ELSEWHERE...SOME UPSLOPE SNOW SHOWERS ARE POSSIBLE FOR THE HIGH
TERRAIN OF WESTERN NEW ENGLAND WITH SOME MINOR SNOW ACCUMULATION
POSSIBLE. THE REMAINDER OF THE REGION LOOKS TO BE DRY...ALTHOUGH
AS THE LAKE BAND SHIFTS SOUTHWARD...THE INLAND EXTENT MAY ALLOW
FOR SOME FLAKES TO REACH THE CAPITAL REGION FOR 08Z-12Z. NOT
EXPECTING MUCH ACCUMULATION...BUT IT/S POSSIBLE FOR A COATING OF
SNOW IN THE ALBANY/SCHENECTADY/TROY AREA BY LATE IN THE NIGHT
TOWARDS DAYBREAK.
MIN TEMPS WILL BE MUCH COOLER THAN LAST NIGHT. MINS WILL RANGE
FROM THE SINGLE DIGITS IN THE ADKS TO THE LOW TO MID 20S IN THE
MID HUDSON VALLEY.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
MAINLY DRY AND SEASONABLY COOL WEATHER IS EXPECTED THROUGH THE
SHORT TERM PERIOD.
THE LAKE BAND WILL SHIFT SOUTH AND WEST OF THE CWA BY FRIDAY
MORNING...MAINLY ENDING THE THREAT FOR LAKE EFFECT IN OUR AREA.
THE EXCEPTION MAY BE A FEW HOURS OF SNOW FOR WESTERN SCHOHARIE
COUNTY WITH SOME LIGHT SNOW ACCUMULATION EARLY FRIDAY MORNING
BEFORE THE BAND SHIFTS AWAY FROM THE AREA. MAX TEMPS WILL BE
NOTICEABLY COOLER...WITH TEENS AND 20S ACROSS THE AREA. IN
ADDITION...DAYTIME MIXING WILL ALLOW FOR SOME GUSTY WINDS...SO IT
WILL FEEL EVEN COLDER...WITH SOME GUSTS OF 15-30 MPH POSSIBLE.
WE WILL CONTINUE TO MENTION LOW CHC OR SLIGHT CHC POPS FOR FAR
WESTERN AREAS FOR FRIDAY AFTERNOON...IN CASE UPSLOPE FLOW DOES
ALLOW FOR SOME LIGHT SNOW SHOWERS...BUT ANY ADDITIONAL SNOW
ACCUMULATION LOOKS LIGHT. THE HUDSON VALLEY AREA SHOULD REMAIN
MAINLY DRY.
CHILLY...BUT SEASONABLE TEMPS...ARE EXPECTED FRIDAY NIGHT WITH
TEMPS RANGING FROM A FEW DEGREES BELOW ZERO ACROSS THE ADIRONDACKS
TO THE MID TEENS IN THE HUDSON VALLEY/NW CT.
A WEAK SHORTWAVE WILL PASS TO THE NORTH OF THE REGION ON SATURDAY
INTO SATURDAY NIGHT. THIS MAY ALLOW FOR SOME LIGHT SNOW SHOWERS
ACROSS THE ADIRONDACKS...OTHERWISE IT LOOKS CONTINUED DRY AND
COOL. MAX TEMPS ON SATURDAY WILL MAINLY BE IN THE TEENS AND 20S.
MIN TEMPS SAT NIGHT WILL RANGE FROM THE SINGLE DIGITS UP NORTH TO
NEAR 20 SOUTH.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
MEAN UPPER TROUGH OVER EASTERN NORTH AMERICA THROUGH THE PERIOD...
WITH LITTLE NORTHERN STREAM IMPULSES TRACKING RAPIDLY THROUGH THE
CYCLONIC FLOW. THE TIMING OF THESE SYSTEMS IN SUCH QUICK UPPER FLOW
IS IN QUESTION BUT TIMED THE BETTER CHANCES FOR SNOW IN THE SUNDAY
TIME FRAME AND AGAIN IN THE MONDAY NIGHT TO TUESDAY TIME FRAME.
THESE SYSTEMS COULD TRACK FAR ENOUGH EAST AND SOUTH OF OUR REGION
THAT THERE COLD BE LITTLE TO NO SNOW IN MUCH OF THE FORECAST AREA...
SO INDICATING BEST CHANCES IN THE MID HUDSON VALLEY...NW CT AND THE
BERKSHIRES. ANY PRECIPITATION WOULD BE RELATIVELY LIGHT IN BOTH
EVENTS...AND SHOULD NOT REQUIRE SNOW HEADLINES SINCE THE STORMS
SHOULD BE STARVED FOR MOISTURE UNTIL THEY RAPIDLY HEAD OFFSHORE AND
WELL EAST OF OUR REGION.
OUTSIDE OF THESE POTENTIAL 2 SMALL EVENTS...SOME PERSISTENT LAKE
EFFECT SNOW BANDS COULD EXTEND INTO THE SOUTHERN ADIRONDACKS...
WESTERN MOHAWK VALLEY...SCHOHARIE VALLEY AND EASTERN CATSKILLS.
SO...PERIODS OF CLOUDS THROUGH THE PERIOD WITH TEMPERATURES AROUND
NORMAL SUNDAY...A LITTLE BELOW NORMAL MONDAY THROUGH WEDNESDAY AND
BACK TO AROUND NORMAL THURSDAY.
&&
.AVIATION /21Z THURSDAY THROUGH TUESDAY/...
THE MAIN PROBLEM THIS AFTERNOON WILL BE THE CONTINUATION STRONG
WINDS OUT OF THE WEST TO NORTHWEST...WHICH WILL OCCASIONALLY GUST
NEAR 40 KT (OR BETTER) ESPECIALLY THIS AFTERNOON AT KALB. A HIGH
WIND WARNING REMAINS IN EFFECT.
THE WIND WILL ABATE SOMEWHAT TONIGHT BUT STILL CONTINUE TO
OCCASIONALLY GUST 20 TO 25 KT OUT OF THE WEST TO NORTHWEST...LESS
GUSTY AFTER ABOUT 02Z. CONDITIONS SHOULD REMAIN MAINLY VFR BUT CIGS
COULD OCCASIONALLY DROP INTO THE HIGH MVFR RANGE AT KPSF DURING THE
NIGHT.
WEST TO NORTHWEST WINDS SHOULD BECOME GUSTY AGAIN TOMORROW AFTER
ABOUT 16Z. IF THE CEILING AT KPSF DROPS TO MVFR TONIGHT...IT SHOULD
BE BACK TO VFR AFTER 12Z.
OUTLOOK...
FRI-MON...MAINLY VFR. CHC SUB-VFR -SHSN.
&&
.HYDROLOGY...
SNOWMELT FROM THE RECENT WARMER TEMPERATURES AND RAINFALL FROM
EARLY THIS MORNING COMBINED FOR SOME RUNOFF ACROSS THE REGION THIS
MORNING. HOWEVER...THIS WAS NOT ENOUGH TO CAUSE FLOODING ACROSS
OUR AREA. WITH TEMPERATURES COOLING BELOW FREEZING ACROSS THE
ENTIRE AREA THIS EVENING...ANY SNOWMELT SHOULD END...AND RIVERS
WILL START TO RECEDE.
BECAUSE OF THE WARM TEMPERATURES AND RAINFALL...SOME ICE BROKE UP
IN AREA RIVERS AND STREAMS. THIS CAUSED SOME MINOR FLOODING ON THE
EAST CANADA CREEK IN DOLGEVILLE AND ALONG THE HOOSIC RIVER NEAR
BUSKIRK. THE THREAT FOR ICE JAMS SHOULD DECREASE THIS EVENING
WITH THE COOLER TEMPERATURES...AND ALTHOUGH ANY ICE THAT BROKE UP
MAY BEGIN TO REFREEZE IN PLACE...LOWERING FLOWS SHOULD PREVENT ANY
FLOODING FROM OCCURRING.
THE NEXT SEVERAL DAYS WILL BE FAIRLY DRY...AND ANY LIGHT
PRECIPITATION WILL BE IN THE FORM OF SNOW. THIS SHOULD ALLOW
RIVERS AND STREAMS TO SLOWLY RECEDE INTO EARLY NEXT WEEK.
FOR SPECIFIC RIVER AND LAKE FORECASTS...PLEASE VISIT THE ADVANCED
HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...HIGH WIND WARNING UNTIL 6 PM EST THIS EVENING FOR CTZ001-013.
NY...HIGH WIND WARNING UNTIL 6 PM EST THIS EVENING FOR NYZ032-033-
038>043-047>054-058>061-063>066-082>084.
LAKE EFFECT SNOW ADVISORY UNTIL 6 AM EST FRIDAY FOR NYZ032-033.
MA...HIGH WIND WARNING UNTIL 6 PM EST THIS EVENING FOR MAZ001-025.
VT...HIGH WIND WARNING UNTIL 6 PM EST THIS EVENING FOR VTZ013>015.
&&
$$
SYNOPSIS...FRUGIS
NEAR TERM...FRUGIS
SHORT TERM...FRUGIS
LONG TERM...NAS
AVIATION...NAS
HYDROLOGY...FRUGIS
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
256 PM CST THU JAN 31 2013
.DISCUSSION...
1016 AM CST
FOR MORNING UPDATE...
HAVE MADE A FEW ADJUSTMENTS TO NEAR TERM FORECAST THIS MORNING... TO
BUMP POPS A BIT FOR OCCASIONAL SNOW SHOWERS. HAVE SEEN SOME ISOLATED
VISIBILITY REDUCTIONS LESS THAN A MILE AT TIMES THIS MORNING WITH A
FEW PLACES PICKING UP A DUSTING TO A TENTH OF AN INCH OR SO. HAVE
ALSO TOUCHED UP SKY COVER GRIDS...ACCOUNT SIGNIFICANT OPEN PATCHES
THIS MORNING ACROSS WEST/SOUTH PARTS OF CWA AND CONVECTIVE NATURE OF
EXPECTED CLOUD COVER THROUGH THE DAY.
MORNING ANALYSIS INDICATES DEEPENING SURFACE LOW CONTINUES TO TRACK
AWAY WELL TO OUR NORTHEAST ACROSS SOUTHERN QUEBEC...WITH COLD FRONT
TRAILING THROUGH NORTHERN INDIANA/CENTRAL ILLINOIS. COLD ARCTIC AIR
CONTINUES TO SPREAD SOUTHEAST ACROSS THE UPPER MIDWEST BEHIND THIS
FRONT...WITH SINGLE DIGIT AND SUB-ZERO TEMPS WIDESPREAD TO OUR
WEST/NORTHWEST. LOOKING ALOFT...RATHER STRONG MID-LEVEL SHORT WAVE
WAS NOTED OVER THE EASTERN DAKOTAS/MINNESOTA...AND THIS WAVE IS
PROGGED TO CONTINUE TO MOVE SOUTHEAST ACROSS OUR AREA THROUGH THIS
EVENING.
SCATTERED SNOW SHOWERS...SOME FAIRLY INTENSE WITH VISIBILITY
REDUCTIONS AND BRIEF MINOR ACCUMULATIONS...HAVE BEEN PREVALENT
ACROSS NORTHEAST IL THIS MORNING. THESE APPEAR TO BE HIGHLY DRIVEN
BY STEEP LOW LEVEL LAPSE RATES AS EVIDENCED BY 12Z ILX RAOB AND
RECENT AIRCRAFT AMDAR SOUNDINGS FROM ORD...WHICH DEPICT ADIABATIC
LOW LEVEL PROFILES FROM THE SURFACE UP TO ABOUT 850-800 MB. THIS
ALSO COINCIDES NICELY WITH THE -12 TO -18C FAVORED TEMPERATURE LAYER
FOR GOOD DENDRITIC GROWTH OF ICE CRYSTALS...OF WHICH HAVE BEEN
OBSERVED AT TIMES THIS MORNING. FORECAST SOUNDINGS FROM MORNING RUNS
OF THE WRF-NAM AND RAP MAINTAIN THESE STEEP LOW LEVEL LAPSE RATES
THROUGH THE DAY...COINCIDENT WITH BETTER MID/UPPER LEVEL FORCING
ASSOCIATED WITH THE APPROACH AND PASSAGE OF AFOREMENTIONED UPPER
MIDWEST SHORT WAVE. DEPSITE DRY ADVECTION OF ARCTIC AIR AND EVEN
THOUGH VIS SATELLITE IMAGERY IS NOT TOO IMPRESSIVE WITH CLOUD
COVER...SUSPECT THAT THIN STRATOCU WILL CONTINUE TO DEVELOP AND
PERHAPS INCREASE IN COVERAGE IN UNSTABLE LOW LEVEL THERMODYNAMIC
ENVIRONMENT...AND SHOULD BE ABLE TO SUSTAIN SNOW SHOWERS AND
FLURRIES WITH SUFFICIENT INTENSITY AT TIMES TO PRODUCE SOME MINOR
ACCUMS IN LOCALIZED AREAS. THEREFORE HAVE BUMPED POPS TO HIGHER
CHANCE CATEGORY...AND WORDED OCCASIONAL SNOW SHOWERS/FLURRIES WITH A
FEW TENTHS OF AN INCH POSSIBLE FOR MUCH OF NORTHERN 2/3 OR SO OF THE
CWA THROUGH THE DAY...AND THIS EVENING. MID-LEVEL TROUGH AXIS MOVES
ACROSS THE REGION LATE EVENING/MIDNIGHT TIME FRAME...AFTER WHICH
FORECAST SOUNDINGS DEPICT STRENGTHENING/LOWERING SUBSIDENCE
INVERSION WHICH SHOULD LIMIT FURTHER MEASURABLE PRECIP THREAT.
OTHERWISE...GOING FORECAST LOOKS GOOD THROUGH THIS AFTERNOON WITH
TEMPS NOT GOING ANYWHERE...AND COLD...BLUSTERY CONDITIONS.
RATZER
//PREV DISCUSSION...
340 AM CST
PRIMARY FORECAST CHALLENGE THIS MORNING IS CLOUD COVER AND ITS
IMPACT ON TEMPS THE NEXT SEVERAL DAYS AS WELL AS FLURRY/LIGHT SNOW
CHANCES.
PHASE ONE OF ARCTIC AIR HAS MOVED INTO THE AREA WITH PHASE 2 STILL
UPSTREAM AND POISED TO ARRIVE THIS AFTERNOON INTO TONIGHT. AS
ALLUDED TO LAST NIGHT GUIDANCE HAS BEEN FAR TOO COLD WITH TEMPS
OVERNIGHT INTO THE EARLY MORNING HOURS THIS MORNING...RUNNING IN
SOME CASES MORE THAN 5F TOO COLD AT 9Z THANKS TO THE CLOUD COVER AND
WIND. NO APPRECIABLE CLEARING IS ANTICIPATED PRIOR TO SUNRISE SO A
VERY SLOW (1-2F EVERY HOUR OR TWO) FALL SHOULD CONTINUE THROUGH
SUNRISE. WITH THE RE-ENFORCING SHOT OF COLD AIR ARRIVING THIS
AFTERNOON AND A GOOD DEAL OF CLOUD COVER/GUSTY NORTHWEST WINDS DONT
ANTICIPATE TEMPS TO REBOUND MUCH FROM EARLY MORNING READINGS WITH
TEMPS FAIRLY STEADY MOST OF THE DAY.
ALONG WITH THE ARRIVAL OF THE COLD AIR...WATER VAPOR IMAGERY SHOWS A
COUPLE OF VORTS UPSTREAM OVER THE NORTHERN PLAINS THAT WILL PIVOT
SOUTHEAST INTO THE AREA THIS AFTERNOON/EVENING. ICE CRYSTALS ARE
LIKELY ALREADY PRESENT IN THE STRATUS DECK GIVEN THE ARCTIC TEMPS SO
IT WILL REMAIN REMARKABLY EASY FOR LIGHT SNOW OR FLURRIES TO FALL
OUT OF THIS STRATUS DECK TODAY INTO TONIGHT...THOUGH ACCUMULATIONS
SHOULD BE MINIMAL FLAKES WILL LIKELY BE FLYING AT TIMES TODAY INTO
THIS EVENING.
CERTAINLY THE AIR MASS ADVECTING INTO THE AREA WILL BE VERY COLD
WITH EVENING SOUNDINGS UPSTREAM SAMPLING 850MB TEMPS NEAR
-20C...HOWEVER ITS NOT CLEAR HOW MUCH IF ANY CLEARING WILL TAKE
PLACE TONIGHT. IN THE ABSENCE OF CLEARING...THE WINDS AND CLOUDS
WOULD LIKELY KEEP TEMPS SEVERAL DEGREES WARMER THAN MOS LOWS AND
SUSPECT THAT CLOUDS WILL LINGER THROUGH THE NIGHT OVER EASTERN CWA
WITH SOME CLEAR LATE WEST. HAVE GENERALLY ADJUSTED LOW TEMPS UPWARD
SOME FROM PREVIOUS FORECAST AND GONE A BIT ABOVE THE WARMER MOS
GUIDANCE NUMBERS AS MODELS SUGGEST THAT LOW LEVEL CYCLONIC FLOW WILL
PERSIST MOST OF THE NIGHT RAISING SERIOUS DOUBTS ABOUT HOW MUCH
CLEARING WILL TAKE PLACE. IN ADDITION...THE AIR MASS THIS GO AROUND
WILL BE A COUPLE/FEW DEGREES MILDER AT 850MB THAN THE PREVIOUS ONE
AND WITH LITTLE/NO SNOW COVER MOST AREAS WOULD EXPECT LOWS TO BOTTOM
OUT NO COLDER THAN LAST GO AROUND AND IN ALL LIKELIHOOD A COUPLE
DEGREES WARMER (WELL LESS COLD). BASED ON THE FORECAST LOWS AND
EXPECTED WINDS LOOKS LIKE NC IL STANDS A REASONABLY GOOD CHANCE OF
REACHING THE -20F WIND CHILL ADVISORY CRITERIA AND SO HAVE GONE
AHEAD AND ISSUED THAT ALREADY THERE. FOR CHICAGO AREA AND POINTS
SOUTH AND EAST IT WILL UNDOUBTEDLY BE VERY COLD TONIGHT BUT APPEARS
UNLIKELY THAT THE -20F CRITERIA WILL BE MET FOR ANY LENGTH OF TIME
SO KEPT ADVISORY NORTH/WEST OF THESE AREAS.
COULD SEE SOME SUNSHINE THE FIRST HALF OF THE DAY ON FRIDAY BUT WILL
REMAIN QUITE COLD WITH CLOUDS ROLLING BACK IN IN THE AFTERNOON AS
FAST MOVING CLIPPER DIVES SE TOWARD THE AREA. VERY LITTLE CHANGE IN
MODEL GUIDANCE IN HANDLING THIS WAVE WITH SWATH OF ACCUMULATING VERY
FLUFFIFIED/HIGH RATION SNOW LIKELY ACROSS NORTHERN/CENTRAL ILLINOIS
FRIDAY NIGHT INTO SATURDAY MORNING. DESPITE LIMITED MOISTURE...HIGH
SNOW:LIQUID RATIOS COULD SUPPORT SOLID 2-3 INCH BAND OF SNOW...WITH
BEST PROJECTIONS AT THIS POINT PLACING THE HEAVIEST SNOW ALONG OR
SOUTH OF I-80. GIVEN HOW LOW AMPLITUDE THIS WAVE IS WOULD NOT BE A
STRETCH TO ENVISION LATER RUNS REFINING THE TRACK A BIT...BUT EVEN
WITH THAT IN MIND FELT FAIRLY COMFORTABLE CONTINUING THE TREND OF
BUMPING POPS UP A BIT HIGHER AGAIN THIS MORNING.
SEEMINGLY NEVER ENDING PARADE OF CLIPPERS ARE PROGGED TO CONTINUE TO
PIVOT AROUND THE BASE OF THE TROUGH HEADING INTO NEXT WEEK. THE 00Z
ECMWF HAS COME IN A BIT DEEPER AND FARTHER WEST WITH THE POLAR
VORTEX OVER THE REGION WHICH WOULD PLACE OUR CWA CLOSER TO THE COLD
SIDE OF THE PATH OF THESE CLIPPERS AND ALSO CLOSER TO POTENTIAL
LIGHT ACCUMULATING SNOWS. THE GEM...GFS...AND PREVIOUS ECMWF WERE
QUICKER TO WEAKEN THE POLAR VORTEX ALLOWING THE CLIPPERS TO PASS TO
OUR NORTH KEEPING US DRY WITH ALTERNATING BOUTS OF ABOVE AVERAGE
TEMPS AND SLIGHT COOL DOWNS WITH A TREND TOWARD SLIGHTLY WEAKER COOL
DOWNS WITH EACH WAVE. CONFIDENCE IS NOT TERRIBLY HIGH IN ANY ONE
SOLUTION AT THIS POINT BUT A TOWARD MODERATING TEMPS DEFINITELY
LOOKS REASONABLE HEADING INTO NEXT WEEK WITH LESS CERTAINTY
REGARDING PRECIP CHANCES.
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* W WIND GUSTING 25-30 KT THROUGH THIS EVENING THEN GUSTS 15-20 KT
OVERNIGHT.
* PERIODS OF -SHSN THROUGH THE EARLY EVENING...HEAVIER BANDS COULD
DROP VSBY DOWN TO LESS THAN A MILE.
* HIGH END MVFR TO LOW END VFR CIGS EXPECTED THROUGH TONIGHT.
JEE
//DISCUSSION...UPDATED 18Z...
AN UPPER LEVEL SHORT WAVE TROUGH MOVED THROUGH THE DAKOTAS AND
PROVIDED FORCING FOR THE BANDS OF SNOW THE AREA SAW EARLIER THIS
MORNING. THE SHORTWAVE IS MOVING INTO IA WITH SHSN FORMING OVER
SOUTHERN WI. AS SUCH KEPT OCNL FLURRIES IN FOR THE TERMINALS
THROUGH 20Z AND EXPECTING MORE SUBSTANTIAL -SHSN AFTER 20Z. THEY
COULD DEVELOP A LITTLE LATER THAN INDICATED...WITH ARND A HALF
INCH OF SNOW PSBL. THE HEAVIER BANDS IN WI ARE ASSOCIATED WITH VSBY
OF LESS THAN 1 MILE...BUT WILL ADDRESS THOSE HEAVIER BANDS AS THEY
SET UP. OVERALL THINKING VSBYS WILL BE 4SM OR BETTER. EXPECTING
CIGS TO DROP A LITTLE WITH THE SNOW AS WELL TO ARND 020. A FEW
UPSTREAM OBS INDICATE 015 CIGS ARE PSBL SO WILL KEEP AN EYE ON HOW
THE LOWER CIGS PROGRESS.
WINDS WILL REMAIN W GUSTING TO 25 KT THROUGH THE MID AFTN WITH
GUSTS INCREASING TO 25-30KT THROUGH THE EVENING. WEST WINDS
GUSTING 15-20 KT ARE THEN EXPECTED OVERNIGHT UNDER THE TIGHTENED
PRESSURE GRADIENT. HIGH PRESSURE SINKS SOUTH TO THE EAST OF THE
TERMINALS ALLOWING SKIES TO SCATTER OUT TOMORROW.
JEE
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE IN PRECIP FCST...MEDIUM CONFIDENCE IN TIMING AND
VSBY ASSOCIATED WITH -SN/-SHSN.
* HIGH CONFIDENCE IN ALL OTHER FCST ELEMENTS.
JEE
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
12Z...
FRIDAY NIGHT...ACCUMULATING SNOW BECOMING LIKELY. MVFR BECOMING
IFR.
SATURDAY...MVFR WITH A CHANCE OF IFR SNOW SHOWERS...MAINLY IN THE
MORNING.
SUNDAY...MVFR.
MONDAY...VFR.
TUESDAY...VFR.
WEDNESDAY...VFR.
TRS
&&
.MARINE...
255 PM CST
GUSTY WEST-NORTHWEST WINDS...ARCTIC AIR AND FREEZING SPRAY ARE THE
MAIN CONCERNS IN THE NEAR TERM...WITH MARGINAL GALE FORCE WINDS
EXPECTED ON THE SOUTH END OF THE LAKE OVERNIGHT. WINDS WILL
GRADUALLY DIMINISH FRIDAY...THOUGH AIR TEMPS IN THE SINGLE DIGITS TO
LOW TEENS WILL LIKELY CONTINUE TO RESULT IN FREEZING SPRAY EARLY IN
THE DAY. HAVE EXTENDED INDIANA NEARSHORE SMALL CRAFT ADVISORY
THROUGH EARLY SATURDAY MORNING...WHERE WAVES WILL BE A LITTLE
SLOWER TO SUBSIDE IN PERSISTENT WEST-NORTHWEST FLOW.
COLD CANADIAN HIGH PRESSURE WILL CONTINUE TO PUSH SOUTHEAST FROM THE
LOWER MISSOURI VALLEY INTO THE SOUTHEASTERN U.S. FRIDAY EVENING...
WITH WEAKER HIGH PRESSURE RIDGING MOVING ACROSS THE WESTERN LAKES
AND ALLOWING THE GRADIENT TO RELAX AND WIND SPEEDS TO DIMINISH MORE
SIGNIFICANTLY. A WEAK LOW WILL MOVE THROUGH THE MIDWEST SATURDAY...
JUST SOUTH OF THE LAKES...WHICH MAKES FOR A LITTLE LOWER CONFIDENCE
IN WIND DIRECTION AS THE GRADIENT REMAINS WEAK/BAGGY NEAR THE
TROUGH. SPEEDS SHOULD BE BELOW 20 KTS HOWEVER. ANOTHER LOW WILL DROP
SOUTHEAST ACROSS THE WESTERN/NORTHERN LAKES LATE SATURDAY NIGHT
HOWEVER AND WILL BRING A RENEWED PUSH OF COLDER AIR...WHICH COMBINED
WITH HIGH PRESSURE ONCE AGAIN MOVING SOUTH ACROSS THE PLAINS WILL
PRODUCE A PERIOD OF GUSTY NORTHWEST WINDS OF 30-35 KTS LATE SATURDAY
NIGHT THROUGH EARLY SUNDAY...HAVE MENTIONED GALES ON THE SOUTH HALF
SUNDAY MORNING. FREEZING SPRAY LIKELY DURING THIS TIME AS WELL...
THOUGH AIR TEMPS WILL BE A BIT WARMER THAN TONIGHT/FRIDAY MORNING.
HIGH PRESSURE THEN SPREADS ACROSS THE REGION AGAIN BY SUNDAY NIGHT
ALLOWING WINDS TO COME DOWN FAIRLY QUICKLY.
LONGER RANGE MODEL GUIDANCE DEVELOPS ANOTHER FAIRLY WEAK LOW WHICH
MOVES ACROSS THE LAKES TUESDAY...THOUGH NO DEEP STORMS THROUGH
MID-WEEK.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WIND CHILL ADVISORY...ILZ003-ILZ004-ILZ005-ILZ008-ILZ010-ILZ011-
ILZ012-ILZ019-ILZ020...MIDNIGHT FRIDAY TO 10 AM FRIDAY.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-
LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 6 AM
FRIDAY.
SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO GARY IN UNTIL 10 AM
FRIDAY.
SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 4 AM SATURDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
159 PM CST THU JAN 31 2013
.DISCUSSION...
1016 AM CST
FOR MORNING UPDATE...
HAVE MADE A FEW ADJUSTMENTS TO NEAR TERM FORECAST THIS MORNING... TO
BUMP POPS A BIT FOR OCCASIONAL SNOW SHOWERS. HAVE SEEN SOME ISOLATED
VISIBILITY REDUCTIONS LESS THAN A MILE AT TIMES THIS MORNING WITH A
FEW PLACES PICKING UP A DUSTING TO A TENTH OF AN INCH OR SO. HAVE
ALSO TOUCHED UP SKY COVER GRIDS...ACCOUNT SIGNIFICANT OPEN PATCHES
THIS MORNING ACROSS WEST/SOUTH PARTS OF CWA AND CONVECTIVE NATURE OF
EXPECTED CLOUD COVER THROUGH THE DAY.
MORNING ANALYSIS INDICATES DEEPENING SURFACE LOW CONTINUES TO TRACK
AWAY WELL TO OUR NORTHEAST ACROSS SOUTHERN QUEBEC...WITH COLD FRONT
TRAILING THROUGH NORTHERN INDIANA/CENTRAL ILLINOIS. COLD ARCTIC AIR
CONTINUES TO SPREAD SOUTHEAST ACROSS THE UPPER MIDWEST BEHIND THIS
FRONT...WITH SINGLE DIGIT AND SUB-ZERO TEMPS WIDESPREAD TO OUR
WEST/NORTHWEST. LOOKING ALOFT...RATHER STRONG MID-LEVEL SHORT WAVE
WAS NOTED OVER THE EASTERN DAKOTAS/MINNESOTA...AND THIS WAVE IS
PROGGED TO CONTINUE TO MOVE SOUTHEAST ACROSS OUR AREA THROUGH THIS
EVENING.
SCATTERED SNOW SHOWERS...SOME FAIRLY INTENSE WITH VISIBILITY
REDUCTIONS AND BRIEF MINOR ACCUMULATIONS...HAVE BEEN PREVALENT
ACROSS NORTHEAST IL THIS MORNING. THESE APPEAR TO BE HIGHLY DRIVEN
BY STEEP LOW LEVEL LAPSE RATES AS EVIDENCED BY 12Z ILX RAOB AND
RECENT AIRCRAFT AMDAR SOUNDINGS FROM ORD...WHICH DEPICT ADIABATIC
LOW LEVEL PROFILES FROM THE SURFACE UP TO ABOUT 850-800 MB. THIS
ALSO COINCIDES NICELY WITH THE -12 TO -18C FAVORED TEMPERATURE LAYER
FOR GOOD DENDRITIC GROWTH OF ICE CRYSTALS...OF WHICH HAVE BEEN
OBSERVED AT TIMES THIS MORNING. FORECAST SOUNDINGS FROM MORNING RUNS
OF THE WRF-NAM AND RAP MAINTAIN THESE STEEP LOW LEVEL LAPSE RATES
THROUGH THE DAY...COINCIDENT WITH BETTER MID/UPPER LEVEL FORCING
ASSOCIATED WITH THE APPROACH AND PASSAGE OF AFOREMENTIONED UPPER
MIDWEST SHORT WAVE. DEPSITE DRY ADVECTION OF ARCTIC AIR AND EVEN
THOUGH VIS SATELLITE IMAGERY IS NOT TOO IMPRESSIVE WITH CLOUD
COVER...SUSPECT THAT THIN STRATOCU WILL CONTINUE TO DEVELOP AND
PERHAPS INCREASE IN COVERAGE IN UNSTABLE LOW LEVEL THERMODYNAMIC
ENVIRONMENT...AND SHOULD BE ABLE TO SUSTAIN SNOW SHOWERS AND
FLURRIES WITH SUFFICIENT INTENSITY AT TIMES TO PRODUCE SOME MINOR
ACCUMS IN LOCALIZED AREAS. THEREFORE HAVE BUMPED POPS TO HIGHER
CHANCE CATEGORY...AND WORDED OCCASIONAL SNOW SHOWERS/FLURRIES WITH A
FEW TENTHS OF AN INCH POSSIBLE FOR MUCH OF NORTHERN 2/3 OR SO OF THE
CWA THROUGH THE DAY...AND THIS EVENING. MID-LEVEL TROUGH AXIS MOVES
ACROSS THE REGION LATE EVENING/MIDNIGHT TIME FRAME...AFTER WHICH
FORECAST SOUNDINGS DEPICT STRENGTHENING/LOWERING SUBSIDENCE
INVERSION WHICH SHOULD LIMIT FURTHER MEASURABLE PRECIP THREAT.
OTHERWISE...GOING FORECAST LOOKS GOOD THROUGH THIS AFTERNOON WITH
TEMPS NOT GOING ANYWHERE...AND COLD...BLUSTERY CONDITIONS.
RATZER
//PREV DISCUSSION...
340 AM CST
PRIMARY FORECAST CHALLENGE THIS MORNING IS CLOUD COVER AND ITS
IMPACT ON TEMPS THE NEXT SEVERAL DAYS AS WELL AS FLURRY/LIGHT SNOW
CHANCES.
PHASE ONE OF ARCTIC AIR HAS MOVED INTO THE AREA WITH PHASE 2 STILL
UPSTREAM AND POISED TO ARRIVE THIS AFTERNOON INTO TONIGHT. AS
ALLUDED TO LAST NIGHT GUIDANCE HAS BEEN FAR TOO COLD WITH TEMPS
OVERNIGHT INTO THE EARLY MORNING HOURS THIS MORNING...RUNNING IN
SOME CASES MORE THAN 5F TOO COLD AT 9Z THANKS TO THE CLOUD COVER AND
WIND. NO APPRECIABLE CLEARING IS ANTICIPATED PRIOR TO SUNRISE SO A
VERY SLOW (1-2F EVERY HOUR OR TWO) FALL SHOULD CONTINUE THROUGH
SUNRISE. WITH THE RE-ENFORCING SHOT OF COLD AIR ARRIVING THIS
AFTERNOON AND A GOOD DEAL OF CLOUD COVER/GUSTY NORTHWEST WINDS DONT
ANTICIPATE TEMPS TO REBOUND MUCH FROM EARLY MORNING READINGS WITH
TEMPS FAIRLY STEADY MOST OF THE DAY.
ALONG WITH THE ARRIVAL OF THE COLD AIR...WATER VAPOR IMAGERY SHOWS A
COUPLE OF VORTS UPSTREAM OVER THE NORTHERN PLAINS THAT WILL PIVOT
SOUTHEAST INTO THE AREA THIS AFTERNOON/EVENING. ICE CRYSTALS ARE
LIKELY ALREADY PRESENT IN THE STRATUS DECK GIVEN THE ARCTIC TEMPS SO
IT WILL REMAIN REMARKABLY EASY FOR LIGHT SNOW OR FLURRIES TO FALL
OUT OF THIS STRATUS DECK TODAY INTO TONIGHT...THOUGH ACCUMULATIONS
SHOULD BE MINIMAL FLAKES WILL LIKELY BE FLYING AT TIMES TODAY INTO
THIS EVENING.
CERTAINLY THE AIR MASS ADVECTING INTO THE AREA WILL BE VERY COLD
WITH EVENING SOUNDINGS UPSTREAM SAMPLING 850MB TEMPS NEAR
-20C...HOWEVER ITS NOT CLEAR HOW MUCH IF ANY CLEARING WILL TAKE
PLACE TONIGHT. IN THE ABSENCE OF CLEARING...THE WINDS AND CLOUDS
WOULD LIKELY KEEP TEMPS SEVERAL DEGREES WARMER THAN MOS LOWS AND
SUSPECT THAT CLOUDS WILL LINGER THROUGH THE NIGHT OVER EASTERN CWA
WITH SOME CLEAR LATE WEST. HAVE GENERALLY ADJUSTED LOW TEMPS UPWARD
SOME FROM PREVIOUS FORECAST AND GONE A BIT ABOVE THE WARMER MOS
GUIDANCE NUMBERS AS MODELS SUGGEST THAT LOW LEVEL CYCLONIC FLOW WILL
PERSIST MOST OF THE NIGHT RAISING SERIOUS DOUBTS ABOUT HOW MUCH
CLEARING WILL TAKE PLACE. IN ADDITION...THE AIR MASS THIS GO AROUND
WILL BE A COUPLE/FEW DEGREES MILDER AT 850MB THAN THE PREVIOUS ONE
AND WITH LITTLE/NO SNOW COVER MOST AREAS WOULD EXPECT LOWS TO BOTTOM
OUT NO COLDER THAN LAST GO AROUND AND IN ALL LIKELIHOOD A COUPLE
DEGREES WARMER (WELL LESS COLD). BASED ON THE FORECAST LOWS AND
EXPECTED WINDS LOOKS LIKE NC IL STANDS A REASONABLY GOOD CHANCE OF
REACHING THE -20F WIND CHILL ADVISORY CRITERIA AND SO HAVE GONE
AHEAD AND ISSUED THAT ALREADY THERE. FOR CHICAGO AREA AND POINTS
SOUTH AND EAST IT WILL UNDOUBTEDLY BE VERY COLD TONIGHT BUT APPEARS
UNLIKELY THAT THE -20F CRITERIA WILL BE MET FOR ANY LENGTH OF TIME
SO KEPT ADVISORY NORTH/WEST OF THESE AREAS.
COULD SEE SOME SUNSHINE THE FIRST HALF OF THE DAY ON FRIDAY BUT WILL
REMAIN QUITE COLD WITH CLOUDS ROLLING BACK IN IN THE AFTERNOON AS
FAST MOVING CLIPPER DIVES SE TOWARD THE AREA. VERY LITTLE CHANGE IN
MODEL GUIDANCE IN HANDLING THIS WAVE WITH SWATH OF ACCUMULATING VERY
FLUFFIFIED/HIGH RATION SNOW LIKELY ACROSS NORTHERN/CENTRAL ILLINOIS
FRIDAY NIGHT INTO SATURDAY MORNING. DESPITE LIMITED MOISTURE...HIGH
SNOW:LIQUID RATIOS COULD SUPPORT SOLID 2-3 INCH BAND OF SNOW...WITH
BEST PROJECTIONS AT THIS POINT PLACING THE HEAVIEST SNOW ALONG OR
SOUTH OF I-80. GIVEN HOW LOW AMPLITUDE THIS WAVE IS WOULD NOT BE A
STRETCH TO ENVISION LATER RUNS REFINING THE TRACK A BIT...BUT EVEN
WITH THAT IN MIND FELT FAIRLY COMFORTABLE CONTINUING THE TREND OF
BUMPING POPS UP A BIT HIGHER AGAIN THIS MORNING.
SEEMINGLY NEVER ENDING PARADE OF CLIPPERS ARE PROGGED TO CONTINUE TO
PIVOT AROUND THE BASE OF THE TROUGH HEADING INTO NEXT WEEK. THE 00Z
ECMWF HAS COME IN A BIT DEEPER AND FARTHER WEST WITH THE POLAR
VORTEX OVER THE REGION WHICH WOULD PLACE OUR CWA CLOSER TO THE COLD
SIDE OF THE PATH OF THESE CLIPPERS AND ALSO CLOSER TO POTENTIAL
LIGHT ACCUMULATING SNOWS. THE GEM...GFS...AND PREVIOUS ECMWF WERE
QUICKER TO WEAKEN THE POLAR VORTEX ALLOWING THE CLIPPERS TO PASS TO
OUR NORTH KEEPING US DRY WITH ALTERNATING BOUTS OF ABOVE AVERAGE
TEMPS AND SLIGHT COOL DOWNS WITH A TREND TOWARD SLIGHTLY WEAKER COOL
DOWNS WITH EACH WAVE. CONFIDENCE IS NOT TERRIBLY HIGH IN ANY ONE
SOLUTION AT THIS POINT BUT A TOWARD MODERATING TEMPS DEFINITELY
LOOKS REASONABLE HEADING INTO NEXT WEEK WITH LESS CERTAINTY
REGARDING PRECIP CHANCES.
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* W WIND GUSTING 25-30 KT THROUGH THIS EVENING THEN GUSTS 15-20 KT
OVERNIGHT.
* PERIODS OF -SHSN THROUGH THE EARLY EVENING...HEAVIER BANDS COULD
DROP VSBY DOWN TO LESS THAN A MILE.
* HIGH END MVFR TO LOW END VFR CIGS EXPECTED THROUGH TONIGHT.
JEE
//DISCUSSION...UPDATED 18Z...
AN UPPER LEVEL SHORT WAVE TROUGH MOVED THROUGH THE DAKOTAS AND
PROVIDED FORCING FOR THE BANDS OF SNOW THE AREA SAW EARLIER THIS
MORNING. THE SHORTWAVE IS MOVING INTO IA WITH SHSN FORMING OVER
SOUTHERN WI. AS SUCH KEPT OCNL FLURRIES IN FOR THE TERMINALS
THROUGH 20Z AND EXPECTING MORE SUBSTANTIAL -SHSN AFTER 20Z. THEY
COULD DEVELOP A LITTLE LATER THAN INDICATED...WITH ARND A HALF
INCH OF SNOW PSBL. THE HEAVIER BANDS IN WI ARE ASSOCIATED WITH VSBY
OF LESS THAN 1 MILE...BUT WILL ADDRESS THOSE HEAVIER BANDS AS THEY
SET UP. OVERALL THINKING VSBYS WILL BE 4SM OR BETTER. EXPECTING
CIGS TO DROP A LITTLE WITH THE SNOW AS WELL TO ARND 020. A FEW
UPSTREAM OBS INDICATE 015 CIGS ARE PSBL SO WILL KEEP AN EYE ON HOW
THE LOWER CIGS PROGRESS.
WINDS WILL REMAIN W GUSTING TO 25 KT THROUGH THE MID AFTN WITH
GUSTS INCREASING TO 25-30KT THROUGH THE EVENING. WEST WINDS
GUSTING 15-20 KT ARE THEN EXPECTED OVERNIGHT UNDER THE TIGHTENED
PRESSURE GRADIENT. HIGH PRESSURE SINKS SOUTH TO THE EAST OF THE
TERMINALS ALLOWING SKIES TO SCATTER OUT TOMORROW.
JEE
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE IN PRECIP FCST...MEDIUM CONFIDENCE IN TIMING AND
VSBY ASSOCIATED WITH -SN/-SHSN.
* HIGH CONFIDENCE IN ALL OTHER FCST ELEMENTS.
JEE
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
12Z...
FRIDAY NIGHT...ACCUMULATING SNOW BECOMING LIKELY. MVFR BECOMING
IFR.
SATURDAY...MVFR WITH A CHANCE OF IFR SNOW SHOWERS...MAINLY IN THE
MORNING.
SUNDAY...MVFR.
MONDAY...VFR.
TUESDAY...VFR.
WEDNESDAY...VFR.
TRS
&&
.MARINE...
446 AM CST
DEEP LOW PRESSURE HAS MOVED FROM GEORGIAN BAY INTO SW QUEBEC
DURING LATE WED EVENING AND EARLY THIS MORNING AND WILL CONTINUE
TO MOVE FURTHER OFF TO THE NE. W TO WNW WINDS HAVE SLACKENED A BIT
AS A RESULT OR THE DECREASING PRESSURE GRADIENT OVER LAKE MI
THOUGH A FEW COASTAL OBSERVATION SITES ALONG THE IN AND FAR SW
LOWER MI SHORED CONTINUED TO MEASURE SOME 35-40KT GALE FORCE
GUSTS. WINDS WILL CONTINUE TO GRADUALLY DIMINISH DURING THE
PREDAWN AND EARLY MORNING HOURS BUT WILL REMAIN BRISK AS STRONG
HIGH PRESSURE CONTINUES TO BUILD SE FROM SOUTHERN SASKATCHEWAN
ACROSS THE NORTHERN AND CENTRAL PLAINS TODAY. WINDS WILL INCREASE
AND REACH GALES ON THE SOUTH PORTION OF THE LAKE BY MID AFTERNOON
AS A SURFACE TROUGH DROPS SE DOWN THE LAKE SPREADING AND ANOTHER
SURGE OF COLD AIR OVER THE REGION. GALE FORCE WINDS AND VERY COLD
AIR WILL RESULT IN FREEZING SPRAY ACROSS THE LAKE. GALES WILL
CONTINUE INTO LATE TONIGHT. BY FRIDAY MORNING A LARGE AREA OF
HIGH PRESSURE WILL BE CENTERED OVER IA AND MO. THE PRESSURE
GRADIENT DECREASES AS THE CENTER OF THE HIGH MOVES NEARER TO THE
AREA AND WINDS ON THE LAKE WILL DIMINISH TO BELOW GALE FORCE BY
FRI MORNING. NW WINDS GRADUALLY BACK TO SW DURING FRI AS THE
CENTER OF THE HIGH MOVES TO KY AND TN BY LATE IN THE AFTERNOON.
TRS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WIND CHILL ADVISORY...ILZ003-ILZ004-ILZ005-ILZ008-ILZ010-
ILZ011...MIDNIGHT FRIDAY TO 10 AM FRIDAY.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-
LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 6 AM
FRIDAY.
SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO GARY IN UNTIL 10 AM
FRIDAY.
SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 4 AM SATURDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1125 AM CST THU JAN 31 2013
.DISCUSSION...
1016 AM CST
FOR MORNING UPDATE...
HAVE MADE A FEW ADJUSTMENTS TO NEAR TERM FORECAST THIS MORNING... TO
BUMP POPS A BIT FOR OCCASIONAL SNOW SHOWERS. HAVE SEEN SOME ISOLATED
VISIBILITY REDUCTIONS LESS THAN A MILE AT TIMES THIS MORNING WITH A
FEW PLACES PICKING UP A DUSTING TO A TENTH OF AN INCH OR SO. HAVE
ALSO TOUCHED UP SKY COVER GRIDS...ACCOUNT SIGNIFICANT OPEN PATCHES
THIS MORNING ACROSS WEST/SOUTH PARTS OF CWA AND CONVECTIVE NATURE OF
EXPECTED CLOUD COVER THROUGH THE DAY.
MORNING ANALYSIS INDICATES DEEPENING SURFACE LOW CONTINUES TO TRACK
AWAY WELL TO OUR NORTHEAST ACROSS SOUTHERN QUEBEC...WITH COLD FRONT
TRAILING THROUGH NORTHERN INDIANA/CENTRAL ILLINOIS. COLD ARCTIC AIR
CONTINUES TO SPREAD SOUTHEAST ACROSS THE UPPER MIDWEST BEHIND THIS
FRONT...WITH SINGLE DIGIT AND SUB-ZERO TEMPS WIDESPREAD TO OUR
WEST/NORTHWEST. LOOKING ALOFT...RATHER STRONG MID-LEVEL SHORT WAVE
WAS NOTED OVER THE EASTERN DAKOTAS/MINNESOTA...AND THIS WAVE IS
PROGGED TO CONTINUE TO MOVE SOUTHEAST ACROSS OUR AREA THROUGH THIS
EVENING.
SCATTERED SNOW SHOWERS...SOME FAIRLY INTENSE WITH VISIBILITY
REDUCTIONS AND BRIEF MINOR ACCUMULATIONS...HAVE BEEN PREVALENT
ACROSS NORTHEAST IL THIS MORNING. THESE APPEAR TO BE HIGHLY DRIVEN
BY STEEP LOW LEVEL LAPSE RATES AS EVIDENCED BY 12Z ILX RAOB AND
RECENT AIRCRAFT AMDAR SOUNDINGS FROM ORD...WHICH DEPICT ADIABATIC
LOW LEVEL PROFILES FROM THE SURFACE UP TO ABOUT 850-800 MB. THIS
ALSO COINCIDES NICELY WITH THE -12 TO -18C FAVORED TEMPERATURE LAYER
FOR GOOD DENDRITIC GROWTH OF ICE CRYSTALS...OF WHICH HAVE BEEN
OBSERVED AT TIMES THIS MORNING. FORECAST SOUNDINGS FROM MORNING RUNS
OF THE WRF-NAM AND RAP MAINTAIN THESE STEEP LOW LEVEL LAPSE RATES
THROUGH THE DAY...COINCIDENT WITH BETTER MID/UPPER LEVEL FORCING
ASSOCIATED WITH THE APPROACH AND PASSAGE OF AFOREMENTIONED UPPER
MIDWEST SHORT WAVE. DEPSITE DRY ADVECTION OF ARCTIC AIR AND EVEN
THOUGH VIS SATELLITE IMAGERY IS NOT TOO IMPRESSIVE WITH CLOUD
COVER...SUSPECT THAT THIN STRATOCU WILL CONTINUE TO DEVELOP AND
PERHAPS INCREASE IN COVERAGE IN UNSTABLE LOW LEVEL THERMODYNAMIC
ENVIRONMENT...AND SHOULD BE ABLE TO SUSTAIN SNOW SHOWERS AND
FLURRIES WITH SUFFICIENT INTENSITY AT TIMES TO PRODUCE SOME MINOR
ACCUMS IN LOCALIZED AREAS. THEREFORE HAVE BUMPED POPS TO HIGHER
CHANCE CATEGORY...AND WORDED OCCASIONAL SNOW SHOWERS/FLURRIES WITH A
FEW TENTHS OF AN INCH POSSIBLE FOR MUCH OF NORTHERN 2/3 OR SO OF THE
CWA THROUGH THE DAY...AND THIS EVENING. MID-LEVEL TROUGH AXIS MOVES
ACROSS THE REGION LATE EVENING/MIDNIGHT TIME FRAME...AFTER WHICH
FORECAST SOUNDINGS DEPICT STRENGTHENING/LOWERING SUBSIDENCE
INVERSION WHICH SHOULD LIMIT FURTHER MEASURABLE PRECIP THREAT.
OTHERWISE...GOING FORECAST LOOKS GOOD THROUGH THIS AFTERNOON WITH
TEMPS NOT GOING ANYWHERE...AND COLD...BLUSTERY CONDITIONS.
RATZER
//PREV DISCUSSION...
340 AM CST
PRIMARY FORECAST CHALLENGE THIS MORNING IS CLOUD COVER AND ITS
IMPACT ON TEMPS THE NEXT SEVERAL DAYS AS WELL AS FLURRY/LIGHT SNOW
CHANCES.
PHASE ONE OF ARCTIC AIR HAS MOVED INTO THE AREA WITH PHASE 2 STILL
UPSTREAM AND POISED TO ARRIVE THIS AFTERNOON INTO TONIGHT. AS
ALLUDED TO LAST NIGHT GUIDANCE HAS BEEN FAR TOO COLD WITH TEMPS
OVERNIGHT INTO THE EARLY MORNING HOURS THIS MORNING...RUNNING IN
SOME CASES MORE THAN 5F TOO COLD AT 9Z THANKS TO THE CLOUD COVER AND
WIND. NO APPRECIABLE CLEARING IS ANTICIPATED PRIOR TO SUNRISE SO A
VERY SLOW (1-2F EVERY HOUR OR TWO) FALL SHOULD CONTINUE THROUGH
SUNRISE. WITH THE RE-ENFORCING SHOT OF COLD AIR ARRIVING THIS
AFTERNOON AND A GOOD DEAL OF CLOUD COVER/GUSTY NORTHWEST WINDS DONT
ANTICIPATE TEMPS TO REBOUND MUCH FROM EARLY MORNING READINGS WITH
TEMPS FAIRLY STEADY MOST OF THE DAY.
ALONG WITH THE ARRIVAL OF THE COLD AIR...WATER VAPOR IMAGERY SHOWS A
COUPLE OF VORTS UPSTREAM OVER THE NORTHERN PLAINS THAT WILL PIVOT
SOUTHEAST INTO THE AREA THIS AFTERNOON/EVENING. ICE CRYSTALS ARE
LIKELY ALREADY PRESENT IN THE STRATUS DECK GIVEN THE ARCTIC TEMPS SO
IT WILL REMAIN REMARKABLY EASY FOR LIGHT SNOW OR FLURRIES TO FALL
OUT OF THIS STRATUS DECK TODAY INTO TONIGHT...THOUGH ACCUMULATIONS
SHOULD BE MINIMAL FLAKES WILL LIKELY BE FLYING AT TIMES TODAY INTO
THIS EVENING.
CERTAINLY THE AIR MASS ADVECTING INTO THE AREA WILL BE VERY COLD
WITH EVENING SOUNDINGS UPSTREAM SAMPLING 850MB TEMPS NEAR
-20C...HOWEVER ITS NOT CLEAR HOW MUCH IF ANY CLEARING WILL TAKE
PLACE TONIGHT. IN THE ABSENCE OF CLEARING...THE WINDS AND CLOUDS
WOULD LIKELY KEEP TEMPS SEVERAL DEGREES WARMER THAN MOS LOWS AND
SUSPECT THAT CLOUDS WILL LINGER THROUGH THE NIGHT OVER EASTERN CWA
WITH SOME CLEAR LATE WEST. HAVE GENERALLY ADJUSTED LOW TEMPS UPWARD
SOME FROM PREVIOUS FORECAST AND GONE A BIT ABOVE THE WARMER MOS
GUIDANCE NUMBERS AS MODELS SUGGEST THAT LOW LEVEL CYCLONIC FLOW WILL
PERSIST MOST OF THE NIGHT RAISING SERIOUS DOUBTS ABOUT HOW MUCH
CLEARING WILL TAKE PLACE. IN ADDITION...THE AIR MASS THIS GO AROUND
WILL BE A COUPLE/FEW DEGREES MILDER AT 850MB THAN THE PREVIOUS ONE
AND WITH LITTLE/NO SNOW COVER MOST AREAS WOULD EXPECT LOWS TO BOTTOM
OUT NO COLDER THAN LAST GO AROUND AND IN ALL LIKELIHOOD A COUPLE
DEGREES WARMER (WELL LESS COLD). BASED ON THE FORECAST LOWS AND
EXPECTED WINDS LOOKS LIKE NC IL STANDS A REASONABLY GOOD CHANCE OF
REACHING THE -20F WIND CHILL ADVISORY CRITERIA AND SO HAVE GONE
AHEAD AND ISSUED THAT ALREADY THERE. FOR CHICAGO AREA AND POINTS
SOUTH AND EAST IT WILL UNDOUBTEDLY BE VERY COLD TONIGHT BUT APPEARS
UNLIKELY THAT THE -20F CRITERIA WILL BE MET FOR ANY LENGTH OF TIME
SO KEPT ADVISORY NORTH/WEST OF THESE AREAS.
COULD SEE SOME SUNSHINE THE FIRST HALF OF THE DAY ON FRIDAY BUT WILL
REMAIN QUITE COLD WITH CLOUDS ROLLING BACK IN IN THE AFTERNOON AS
FAST MOVING CLIPPER DIVES SE TOWARD THE AREA. VERY LITTLE CHANGE IN
MODEL GUIDANCE IN HANDLING THIS WAVE WITH SWATH OF ACCUMULATING VERY
FLUFFIFIED/HIGH RATION SNOW LIKELY ACROSS NORTHERN/CENTRAL ILLINOIS
FRIDAY NIGHT INTO SATURDAY MORNING. DESPITE LIMITED MOISTURE...HIGH
SNOW:LIQUID RATIOS COULD SUPPORT SOLID 2-3 INCH BAND OF SNOW...WITH
BEST PROJECTIONS AT THIS POINT PLACING THE HEAVIEST SNOW ALONG OR
SOUTH OF I-80. GIVEN HOW LOW AMPLITUDE THIS WAVE IS WOULD NOT BE A
STRETCH TO ENVISION LATER RUNS REFINING THE TRACK A BIT...BUT EVEN
WITH THAT IN MIND FELT FAIRLY COMFORTABLE CONTINUING THE TREND OF
BUMPING POPS UP A BIT HIGHER AGAIN THIS MORNING.
SEEMINGLY NEVER ENDING PARADE OF CLIPPERS ARE PROGGED TO CONTINUE TO
PIVOT AROUND THE BASE OF THE TROUGH HEADING INTO NEXT WEEK. THE 00Z
ECMWF HAS COME IN A BIT DEEPER AND FARTHER WEST WITH THE POLAR
VORTEX OVER THE REGION WHICH WOULD PLACE OUR CWA CLOSER TO THE COLD
SIDE OF THE PATH OF THESE CLIPPERS AND ALSO CLOSER TO POTENTIAL
LIGHT ACCUMULATING SNOWS. THE GEM...GFS...AND PREVIOUS ECMWF WERE
QUICKER TO WEAKEN THE POLAR VORTEX ALLOWING THE CLIPPERS TO PASS TO
OUR NORTH KEEPING US DRY WITH ALTERNATING BOUTS OF ABOVE AVERAGE
TEMPS AND SLIGHT COOL DOWNS WITH A TREND TOWARD SLIGHTLY WEAKER COOL
DOWNS WITH EACH WAVE. CONFIDENCE IS NOT TERRIBLY HIGH IN ANY ONE
SOLUTION AT THIS POINT BUT A TOWARD MODERATING TEMPS DEFINITELY
LOOKS REASONABLE HEADING INTO NEXT WEEK WITH LESS CERTAINTY
REGARDING PRECIP CHANCES.
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* W WIND GUSTING 20-25KT THROUGH EARLY AFTERNOON...THEN GUSTING
25-30KT LATE AFTN AND THROUGH THE EVENING.
* SCATTERED -SN/FLURRIES PASSING OVER THE TERMINALS THROUGH 20Z
THEN A PERIOD OF -SHSN LATE THIS AFTN/EARLY EVENING.
* HIGH END MVFR TO LOW END VFR CIGS EXPECTED THROUGH TONIGHT.
JEE
//DISCUSSION...UPDATED 18Z...
AN UPPER LEVEL SHORT WAVE TROUGH MOVED THROUGH THE DAKOTAS AND
PROVIDED FORCING FOR THE BANDS OF SNOW THE AREA SAW EARLIER THIS
MORNING. THE SHORTWAVE IS MOVING INTO IA WITH SHSN FORMING OVER
SOUTHERN WI. AS SUCH KEPT OCNL FLURRIES IN FOR THE TERMINALS
THROUGH 20Z AND EXPECTING MORE SUBSTANTIAL -SHSN AFTER 20Z. THEY
COULD DEVELOP A LITTLE LATER THAN INDICATED...WITH ARND A HALF
INCH OF SNOW PSBL. THE HEAVIER BANDS IN WI ARE ASSOCIATED WITH VSBY
OF LESS THAN 1 MILE...BUT WILL ADDRESS THOSE HEAVIER BANDS AS THEY
SET UP. OVERALL THINKING VSBYS WILL BE 4SM OR BETTER. EXPECTING
CIGS TO DROP A LITTLE WITH THE SNOW AS WELL TO ARND 020. A FEW
UPSTREAM OBS INDICATE 015 CIGS ARE PSBL SO WILL KEEP AN EYE ON HOW
THE LOWER CIGS PROGRESS.
WINDS WILL REMAIN W GUSTING TO 25 KT THROUGH THE MID AFTN WITH
GUSTS INCREASING TO 25-30KT THROUGH THE EVENING. WEST WINDS
GUSTING 15-20 KT ARE THEN EXPECTED OVERNIGHT UNDER THE TIGHTENED
PRESSURE GRADIENT. HIGH PRESSURE SINKS SOUTH TO THE EAST OF THE
TERMINALS ALLOWING SKIES TO SCATTER OUT TOMORROW.
JEE
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH CONFIDENCE IN PRECIP FCST...MEDIUM CONFIDENCE IN TIMING AND
VSBY ASSOCIATED WITH -SN/-SHSN.
* HIGH CONFIDENCE IN ALL OTHER FCST ELEMENTS.
JEE
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
12Z...
FRIDAY NIGHT...ACCUMULATING SNOW BECOMING LIKELY. MVFR BECOMING
IFR.
SATURDAY...MVFR WITH A CHANCE OF IFR SNOW SHOWERS...MAINLY IN THE
MORNING.
SUNDAY...MVFR.
MONDAY...VFR.
TUESDAY...VFR.
WEDNESDAY...VFR.
TRS
&&
.MARINE...
446 AM CST
DEEP LOW PRESSURE HAS MOVED FROM GEORGIAN BAY INTO SW QUEBEC
DURING LATE WED EVENING AND EARLY THIS MORNING AND WILL CONTINUE
TO MOVE FURTHER OFF TO THE NE. W TO WNW WINDS HAVE SLACKENED A BIT
AS A RESULT OR THE DECREASING PRESSURE GRADIENT OVER LAKE MI
THOUGH A FEW COASTAL OBSERVATION SITES ALONG THE IN AND FAR SW
LOWER MI SHORED CONTINUED TO MEASURE SOME 35-40KT GALE FORCE
GUSTS. WINDS WILL CONTINUE TO GRADUALLY DIMINISH DURING THE
PREDAWN AND EARLY MORNING HOURS BUT WILL REMAIN BRISK AS STRONG
HIGH PRESSURE CONTINUES TO BUILD SE FROM SOUTHERN SASKATCHEWAN
ACROSS THE NORTHERN AND CENTRAL PLAINS TODAY. WINDS WILL INCREASE
AND REACH GALES ON THE SOUTH PORTION OF THE LAKE BY MID AFTERNOON
AS A SURFACE TROUGH DROPS SE DOWN THE LAKE SPREADING AND ANOTHER
SURGE OF COLD AIR OVER THE REGION. GALE FORCE WINDS AND VERY COLD
AIR WILL RESULT IN FREEZING SPRAY ACROSS THE LAKE. GALES WILL
CONTINUE INTO LATE TONIGHT. BY FRIDAY MORNING A LARGE AREA OF
HIGH PRESSURE WILL BE CENTERED OVER IA AND MO. THE PRESSURE
GRADIENT DECREASES AS THE CENTER OF THE HIGH MOVES NEARER TO THE
AREA AND WINDS ON THE LAKE WILL DIMINISH TO BELOW GALE FORCE BY
FRI MORNING. NW WINDS GRADUALLY BACK TO SW DURING FRI AS THE
CENTER OF THE HIGH MOVES TO KY AND TN BY LATE IN THE AFTERNOON.
TRS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WIND CHILL ADVISORY...ILZ003-ILZ004-ILZ005-ILZ008-ILZ010-
ILZ011...MIDNIGHT FRIDAY TO 10 AM FRIDAY.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-
LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...3 PM
THURSDAY TO 6 AM FRIDAY.
SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO GARY IN UNTIL 10 AM
FRIDAY.
SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 4 PM FRIDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1017 AM CST THU JAN 31 2013
.DISCUSSION...
1016 AM CST
FOR MORNING UPDATE...
HAVE MADE A FEW ADJUSTMENTS TO NEAR TERM FORECAST THIS MORNING... TO
BUMP POPS A BIT FOR OCCASIONAL SNOW SHOWERS. HAVE SEEN SOME ISOLATED
VISIBILITY REDUCTIONS LESS THAN A MILE AT TIMES THIS MORNING WITH A
FEW PLACES PICKING UP A DUSTING TO A TENTH OF AN INCH OR SO. HAVE
ALSO TOUCHED UP SKY COVER GRIDS...ACCOUNT SIGNIFICANT OPEN PATCHES
THIS MORNING ACROSS WEST/SOUTH PARTS OF CWA AND CONVECTIVE NATURE OF
EXPECTED CLOUD COVER THROUGH THE DAY.
MORNING ANALYSIS INDICATES DEEPENING SURFACE LOW CONTINUES TO TRACK
AWAY WELL TO OUR NORTHEAST ACROSS SOUTHERN QUEBEC...WITH COLD FRONT
TRAILING THROUGH NORTHERN INDIANA/CENTRAL ILLINOIS. COLD ARCTIC AIR
CONTINUES TO SPREAD SOUTHEAST ACROSS THE UPPER MIDWEST BEHIND THIS
FRONT...WITH SINGLE DIGIT AND SUB-ZERO TEMPS WIDESPREAD TO OUR
WEST/NORTHWEST. LOOKING ALOFT...RATHER STRONG MID-LEVEL SHORT WAVE
WAS NOTED OVER THE EASTERN DAKOTAS/MINNESOTA...AND THIS WAVE IS
PROGGED TO CONTINUE TO MOVE SOUTHEAST ACROSS OUR AREA THROUGH THIS
EVENING.
SCATTERED SNOW SHOWERS...SOME FAIRLY INTENSE WITH VISIBILITY
REDUCTIONS AND BRIEF MINOR ACCUMULATIONS...HAVE BEEN PREVALENT
ACROSS NORTHEAST IL THIS MORNING. THESE APPEAR TO BE HIGHLY DRIVEN
BY STEEP LOW LEVEL LAPSE RATES AS EVIDENCED BY 12Z ILX RAOB AND
RECENT AIRCRAFT AMDAR SOUNDINGS FROM ORD...WHICH DEPICT ADIABATIC
LOW LEVEL PROFILES FROM THE SURFACE UP TO ABOUT 850-800 MB. THIS
ALSO COINCIDES NICELY WITH THE -12 TO -18C FAVORED TEMPERATURE LAYER
FOR GOOD DENDRITIC GROWTH OF ICE CRYSTALS...OF WHICH HAVE BEEN
OBSERVED AT TIMES THIS MORNING. FORECAST SOUNDINGS FROM MORNING RUNS
OF THE WRF-NAM AND RAP MAINTAIN THESE STEEP LOW LEVEL LAPSE RATES
THROUGH THE DAY...COINCIDENT WITH BETTER MID/UPPER LEVEL FORCING
ASSOCIATED WITH THE APPROACH AND PASSAGE OF AFOREMENTIONED UPPER
MIDWEST SHORT WAVE. DEPSITE DRY ADVECTION OF ARCTIC AIR AND EVEN
THOUGH VIS SATELLITE IMAGERY IS NOT TOO IMPRESSIVE WITH CLOUD
COVER...SUSPECT THAT THIN STRATOCU WILL CONTINUE TO DEVELOP AND
PERHAPS INCREASE IN COVERAGE IN UNSTABLE LOW LEVEL THERMODYNAMIC
ENVIRONMENT...AND SHOULD BE ABLE TO SUSTAIN SNOW SHOWERS AND
FLURRIES WITH SUFFICIENT INTENSITY AT TIMES TO PRODUCE SOME MINOR
ACCUMS IN LOCALIZED AREAS. THEREFORE HAVE BUMPED POPS TO HIGHER
CHANCE CATEGORY...AND WORDED OCCASIONAL SNOW SHOWERS/FLURRIES WITH A
FEW TENTHS OF AN INCH POSSIBLE FOR MUCH OF NORTHERN 2/3 OR SO OF THE
CWA THROUGH THE DAY...AND THIS EVENING. MID-LEVEL TROUGH AXIS MOVES
ACROSS THE REGION LATE EVENING/MIDNIGHT TIME FRAME...AFTER WHICH
FORECAST SOUNDINGS DEPICT STRENGTHENING/LOWERING SUBSIDENCE
INVERSION WHICH SHOULD LIMIT FURTHER MEASURABLE PRECIP THREAT.
OTHERWISE...GOING FORECAST LOOKS GOOD THROUGH THIS AFTERNOON WITH
TEMPS NOT GOING ANYWHERE...AND COLD...BLUSTERY CONDITIONS.
RATZER
&&
.PREV DISCUSSION...
340 AM CST
PRIMARY FORECAST CHALLENGE THIS MORNING IS CLOUD COVER AND ITS
IMPACT ON TEMPS THE NEXT SEVERAL DAYS AS WELL AS FLURRY/LIGHT SNOW
CHANCES.
PHASE ONE OF ARCTIC AIR HAS MOVED INTO THE AREA WITH PHASE 2 STILL
UPSTREAM AND POISED TO ARRIVE THIS AFTERNOON INTO TONIGHT. AS
ALLUDED TO LAST NIGHT GUIDANCE HAS BEEN FAR TOO COLD WITH TEMPS
OVERNIGHT INTO THE EARLY MORNING HOURS THIS MORNING...RUNNING IN
SOME CASES MORE THAN 5F TOO COLD AT 9Z THANKS TO THE CLOUD COVER AND
WIND. NO APPRECIABLE CLEARING IS ANTICIPATED PRIOR TO SUNRISE SO A
VERY SLOW (1-2F EVERY HOUR OR TWO) FALL SHOULD CONTINUE THROUGH
SUNRISE. WITH THE RE-ENFORCING SHOT OF COLD AIR ARRIVING THIS
AFTERNOON AND A GOOD DEAL OF CLOUD COVER/GUSTY NORTHWEST WINDS DONT
ANTICIPATE TEMPS TO REBOUND MUCH FROM EARLY MORNING READINGS WITH
TEMPS FAIRLY STEADY MOST OF THE DAY.
ALONG WITH THE ARRIVAL OF THE COLD AIR...WATER VAPOR IMAGERY SHOWS A
COUPLE OF VORTS UPSTREAM OVER THE NORTHERN PLAINS THAT WILL PIVOT
SOUTHEAST INTO THE AREA THIS AFTERNOON/EVENING. ICE CRYSTALS ARE
LIKELY ALREADY PRESENT IN THE STRATUS DECK GIVEN THE ARCTIC TEMPS SO
IT WILL REMAIN REMARKABLY EASY FOR LIGHT SNOW OR FLURRIES TO FALL
OUT OF THIS STRATUS DECK TODAY INTO TONIGHT...THOUGH ACCUMULATIONS
SHOULD BE MINIMAL FLAKES WILL LIKELY BE FLYING AT TIMES TODAY INTO
THIS EVENING.
CERTAINLY THE AIR MASS ADVECTING INTO THE AREA WILL BE VERY COLD
WITH EVENING SOUNDINGS UPSTREAM SAMPLING 850MB TEMPS NEAR
-20C...HOWEVER ITS NOT CLEAR HOW MUCH IF ANY CLEARING WILL TAKE
PLACE TONIGHT. IN THE ABSENCE OF CLEARING...THE WINDS AND CLOUDS
WOULD LIKELY KEEP TEMPS SEVERAL DEGREES WARMER THAN MOS LOWS AND
SUSPECT THAT CLOUDS WILL LINGER THROUGH THE NIGHT OVER EASTERN CWA
WITH SOME CLEAR LATE WEST. HAVE GENERALLY ADJUSTED LOW TEMPS UPWARD
SOME FROM PREVIOUS FORECAST AND GONE A BIT ABOVE THE WARMER MOS
GUIDANCE NUMBERS AS MODELS SUGGEST THAT LOW LEVEL CYCLONIC FLOW WILL
PERSIST MOST OF THE NIGHT RAISING SERIOUS DOUBTS ABOUT HOW MUCH
CLEARING WILL TAKE PLACE. IN ADDITION...THE AIR MASS THIS GO AROUND
WILL BE A COUPLE/FEW DEGREES MILDER AT 850MB THAN THE PREVIOUS ONE
AND WITH LITTLE/NO SNOW COVER MOST AREAS WOULD EXPECT LOWS TO BOTTOM
OUT NO COLDER THAN LAST GO AROUND AND IN ALL LIKELIHOOD A COUPLE
DEGREES WARMER (WELL LESS COLD). BASED ON THE FORECAST LOWS AND
EXPECTED WINDS LOOKS LIKE NC IL STANDS A REASONABLY GOOD CHANCE OF
REACHING THE -20F WIND CHILL ADVISORY CRITERIA AND SO HAVE GONE
AHEAD AND ISSUED THAT ALREADY THERE. FOR CHICAGO AREA AND POINTS
SOUTH AND EAST IT WILL UNDOUBTEDLY BE VERY COLD TONIGHT BUT APPEARS
UNLIKELY THAT THE -20F CRITERIA WILL BE MET FOR ANY LENGTH OF TIME
SO KEPT ADVISORY NORTH/WEST OF THESE AREAS.
COULD SEE SOME SUNSHINE THE FIRST HALF OF THE DAY ON FRIDAY BUT WILL
REMAIN QUITE COLD WITH CLOUDS ROLLING BACK IN IN THE AFTERNOON AS
FAST MOVING CLIPPER DIVES SE TOWARD THE AREA. VERY LITTLE CHANGE IN
MODEL GUIDANCE IN HANDLING THIS WAVE WITH SWATH OF ACCUMULATING VERY
FLUFFIFIED/HIGH RATION SNOW LIKELY ACROSS NORTHERN/CENTRAL ILLINOIS
FRIDAY NIGHT INTO SATURDAY MORNING. DESPITE LIMITED MOISTURE...HIGH
SNOW:LIQUID RATIOS COULD SUPPORT SOLID 2-3 INCH BAND OF SNOW...WITH
BEST PROJECTIONS AT THIS POINT PLACING THE HEAVIEST SNOW ALONG OR
SOUTH OF I-80. GIVEN HOW LOW AMPLITUDE THIS WAVE IS WOULD NOT BE A
STRETCH TO ENVISION LATER RUNS REFINING THE TRACK A BIT...BUT EVEN
WITH THAT IN MIND FELT FAIRLY COMFORTABLE CONTINUING THE TREND OF
BUMPING POPS UP A BIT HIGHER AGAIN THIS MORNING.
SEEMINGLY NEVER ENDING PARADE OF CLIPPERS ARE PROGGED TO CONTINUE TO
PIVOT AROUND THE BASE OF THE TROUGH HEADING INTO NEXT WEEK. THE 00Z
ECMWF HAS COME IN A BIT DEEPER AND FARTHER WEST WITH THE POLAR
VORTEX OVER THE REGION WHICH WOULD PLACE OUR CWA CLOSER TO THE COLD
SIDE OF THE PATH OF THESE CLIPPERS AND ALSO CLOSER TO POTENTIAL
LIGHT ACCUMULATING SNOWS. THE GEM...GFS...AND PREVIOUS ECMWF WERE
QUICKER TO WEAKEN THE POLAR VORTEX ALLOWING THE CLIPPERS TO PASS TO
OUR NORTH KEEPING US DRY WITH ALTERNATING BOUTS OF ABOVE AVERAGE
TEMPS AND SLIGHT COOL DOWNS WITH A TREND TOWARD SLIGHTLY WEAKER COOL
DOWNS WITH EACH WAVE. CONFIDENCE IS NOT TERRIBLY HIGH IN ANY ONE
SOLUTION AT THIS POINT BUT A TOWARD MODERATING TEMPS DEFINITELY
LOOKS REASONABLE HEADING INTO NEXT WEEK WITH LESS CERTAINTY
REGARDING PRECIP CHANCES.
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* W WIND GUSTING 20-25KT THROUGH EARLY AFTERNOON...THEN GUSTING
25-30KT LATE AFTN AND THROUGH THE EVENING.
* SCATTERED -SN/FLURRIES PASSING OVER THE TERMINALS THROUGH 20Z
THEN A PERIOD OF -SHSN LATE THIS AFTN/EARLY EVENING.
* HIGH END MVFR TO LOW END VFR CIGS EXPECTED.
JEE
//DISCUSSION...UPDATED 12Z...
ANOTHER MID LEVEL SHORT WAVE TROUGH WAS MOVING OVER NORTHERN WI...
CENTRAL MN AND SE ND EARLY THIS MORNING CONTINUING TO GENERATE
LIGHT SNOW ACROSS THE AREA. BANDS OF SOMEWHAT HEAVER SNOW
OCCASIONALLY PASS OVER ORD AND/OR MDW AND BRIEFLY DROP VISIBILITY
DOWN TO 3-5SM. THIS SNOW WILL PERSIST UNTIL THE TROUGH AXIS PASSES
BY...WHICH IS EXPECTED IN THE 13Z TO 15Z WINDOW. SOME FLURRIES MAY
LINGER THE REST OF THE MORNING BUT WILL NOT BE A RESTRICTION TO
VISIBILITY.
ANOTHER SHORT WAVE TROUGH...CURRENTLY OVER NORTHERN ND AND
MN...WILL CONTINUE TO DROP ESE THIS MORNING AND MOVE TO OVER SE
WI...NORTHERN IL AND SOUTHERN IA BY 00Z. SNOWFALL OF ANY
SIGNIFICANCE FROM THIS DISTURBANCE IS EXPECTED TO REMAIN MAINLY TO
THE NW AND N OF THE CHI AREA WITH JUST MORE FLURRIES...AND
POSSIBLY SOME VERY LIGHT SNOW SHOWERS...FOR THE LOCAL AREA DURING
THE LATE AFTERNOON AND EARLY EVENING.
WINDS SETTLED DOWN DURING THE OVERNIGHT THE TIGHTER PRESSURE
GRADIENT SHIFTED E. THE GRADIENT TIGHTENS AGAIN THIS MORNING WITH
W-WNW WINDS GUSTING BACK UP INTO 25-30KT RANGE BY LATE MORNING AS
THE HIGH PRESSURE RIDGE THAT EXTENDS S ACROSS SW SASKATCHEWAN SE
TO THE CENTRAL PLAINS GRADUALLY MOVES SE. WITH THE HIGH
CONTINUING TO THE SE THIS EVENING AND OVERNIGHT WINDS WILL DROP
OFF AGAIN AS THE GRADIENT ONCE AGAIN RELAXES.
MODEL RH FIELDS OF THE LOWER LAYERS SUGGEST THE CURRENT MVFR
CEILINGS WILL RISE TO VFR THIS MORNING THEN DROP BACK TO MVFR THIS
AFTERNOON.
TRS
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* HIGH CONFIDENCE IN PRECIP FCST...MEDIUM CONFIDENCE IN VSBY
ASSOCIATED WITH -SN.
* HIGH CONFIDENCE IN ALL OTHER FCST ELEMENTS.
JEE
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
12Z...
FRIDAY NIGHT...ACCUMULATING SNOW BECOMING LIKELY. MVFR BECOMING
IFR.
SATURDAY...MVFR WITH A CHANCE OF IFR SNOW SHOWERS...MAINLY IN THE
MORNING.
SUNDAY...MVFR.
MONDAY...VFR.
TUESDAY...VFR.
WEDNESDAY...VFR.
TRS
&&
.MARINE...
446 AM CST
DEEP LOW PRESSURE HAS MOVED FROM GEORGIAN BAY INTO SW QUEBEC
DURING LATE WED EVENING AND EARLY THIS MORNING AND WILL CONTINUE
TO MOVE FURTHER OFF TO THE NE. W TO WNW WINDS HAVE SLACKENED A BIT
AS A RESULT OR THE DECREASING PRESSURE GRADIENT OVER LAKE MI
THOUGH A FEW COASTAL OBSERVATION SITES ALONG THE IN AND FAR SW
LOWER MI SHORED CONTINUED TO MEASURE SOME 35-40KT GALE FORCE
GUSTS. WINDS WILL CONTINUE TO GRADUALLY DIMINISH DURING THE
PREDAWN AND EARLY MORNING HOURS BUT WILL REMAIN BRISK AS STRONG
HIGH PRESSURE CONTINUES TO BUILD SE FROM SOUTHERN SASKATCHEWAN
ACROSS THE NORTHERN AND CENTRAL PLAINS TODAY. WINDS WILL INCREASE
AND REACH GALES ON THE SOUTH PORTION OF THE LAKE BY MID AFTERNOON
AS A SURFACE TROUGH DROPS SE DOWN THE LAKE SPREADING AND ANOTHER
SURGE OF COLD AIR OVER THE REGION. GALE FORCE WINDS AND VERY COLD
AIR WILL RESULT IN FREEZING SPRAY ACROSS THE LAKE. GALES WILL
CONTINUE INTO LATE TONIGHT. BY FRIDAY MORNING A LARGE AREA OF
HIGH PRESSURE WILL BE CENTERED OVER IA AND MO. THE PRESSURE
GRADIENT DECREASES AS THE CENTER OF THE HIGH MOVES NEARER TO THE
AREA AND WINDS ON THE LAKE WILL DIMINISH TO BELOW GALE FORCE BY
FRI MORNING. NW WINDS GRADUALLY BACK TO SW DURING FRI AS THE
CENTER OF THE HIGH MOVES TO KY AND TN BY LATE IN THE AFTERNOON.
TRS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WIND CHILL ADVISORY...ILZ003-ILZ004-ILZ005-ILZ008-ILZ010-
ILZ011...MIDNIGHT FRIDAY TO 10 AM FRIDAY.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-
LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...3 PM
THURSDAY TO 6 AM FRIDAY.
SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO GARY IN UNTIL 10 AM
FRIDAY.
SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 4 PM FRIDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1119 AM MST THU JAN 31 2013
.UPDATE...
ISSUED AT 1115 AM MST THU JAN 31 2013
UPDATED TEMPERATURES FOR TODAY. COLD AIR IS MAKING ITS IMPACT
ESPECIALLY IN THE EASTERN FA WITH MCK TEMPERATURES STEADILY
FALLING ABOUT A DEGREE PER HOUR. EXPECT THAT TREND TO WORK ITS WAY
SLOWLY WEST ACROSS THE FA. ALSO LOWERED TONIGHT AND FRIDAY
TEMPERATURES.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY NIGHT)
ISSUED AT 412 AM MST THU JAN 31 2013
FORECAST PROBLEMS WILL PROBLEMATIC TEMPERATURE FORECAST INTO TONIGHT
AND HOW MUCH TO WARM UP THE HIGH TEMPERATURES INTO SATURDAY.
SATELLITE SHOWING A BROAD UPPER TROUGH OVER THE TROUGH OVER THE
WESTERN AND CENTRAL PACIFIC WITH A RIDGE ALONG THE WEST COAST OF
NORTH AMERICA. A COUPLE OF SYSTEMS COMING INTO THE RIDGE ARE BEATING
IT DOWN. A STRONG AND COLD SYSTEM IS DIGGING INTO THE NORTH CENTRAL
PORTION OF THE COUNTRY. VERY COLD AIR MASS HAS MOVED FURTHER SOUTH
FROM YESTERDAY AND IS NOT TOO FAR NORTH AND EAST OF OUR AREA.
MODELS INITIALIZED WELL AT JET LEVEL WITH THE CANADIAN...GFS...AND
NAM DOING THE BEST. MODELS INITIALIZED WELL AT MID LEVELS WITH THE
GFS...CANADIAN...AND NAM DOING SLIGHTLY BETTER. LARGER SCALE MODELS
DO NOT HAVE THE BACKDOOR COLD FRONT FAR ENOUGH SOUTH AND WEST BY
06Z...OH SURPRISE. THE RUC HAS CONTINUED TO GET BETTER AS THE
NIGHT HAS PROGRESSED. OUTSIDE OF THE RUC ON THE LOW LEVEL THERMAL
FIELD...THE ECMWF AND GFS WERE DOING A LITTLE BETTER THAN THE UKMET
AND NAM.
TODAY/TONIGHT...VERY THICK CLOUD COVER HAS SPREAD OVER THE AREA
THROUGH THE NIGHT. WHAT THIS HAS DONE HAS PREVENTED ANY FALL OF THE
TEMPERATURES AND IN FACT HAS CAUSED THE TEMPERATURES TO RISE SOME.
NWP OUTPUT MUST BE UNDERDOING THIS CLOUD COVER AND IS TOO COOL WITH
TEMPERATURES. THIS CLOUD COVER IS BEING CAUSED BY STRONG MID TO
UPPER LEVEL JET. SOUNDINGS AND PLAN VIEW RELATIVE HUMIDITY PLOTS SHOW
THIS CLOUD COVER LASTING MOST OF THE DAY...ESPECIALLY IN THE
NORTHEAST PORTION.
BACKDOOR COLD FRONT WITH VERY COLD AIR BEHIND IT HAS BEEN MOVING
STEADILY TOWARD THE AREA THROUGH THE NIGHT AND IS NOT THAT FAR
AWAY. RUC IS CATCHING ONTO THIS AT THIS TIME. INITIALLY WAS GOING TO
CUT HIGH TEMPERATURES FROM GOING FORECAST BUT CLOUD COVER HAS
COMPLICATED THAT. SO WILL BE STARTING MUCH WARMER THAN WHAT MOST OF
THE MODELS SAY. FRONT SAGS ACROSS THE AREA THROUGH THE DAY WITH
SOME LOCATIONS IN THE NORTHEAST HALF TO TWO THIRDS REACHING THEIR
MAX BY 18Z. SO COMBINING REALITY AND THE RUC ADJUSTED MAX
TEMPERATURES UP BUT HAVE EXTREMELY LOW CONFIDENCE ABOUT THIS. DID
NOT GOES AS WARM AS IT BECAUSE OF THE CLOUD COVER. HRRR WOULD
INDICATE HIGH TEMPERATURES ABOUT 10 DEGREES WARMER IN THE SOUTHWEST
PORTION OF THE AREA THAT WHAT I HAVE.
LEFT FRONT QUADRANT OF INCOMING JET WILL CONTINUE TO AFFECT THE
NORTHEAST HALF TO TWO THIRDS OF THE AREA INTO EARLY AFTERNOON.
SEVERAL STATIONS HAVE REPORTED BRIEF PERIODS OF FLURRIES. ALL MODEL
OUTPUT AGREES IN PLACING LIGHT QPF IN THE ABOVE MENTIONED AREA. SREF
PROBABILITIES AGREE WITH THAT. IT MAKES SENSE WITH THE JET...
MESOSCALE FORCING AND LAPSE RATES IN PLACE. HOWEVER...DRIER AIR
IN THE LOWEST LAYERS. SO INTRODUCED SCATTERED FLURRIES THROUGH
MIDDAY WHEN THE FORCING AND MOISTURE LEAVE.
PROBLEMATIC MIN FORECAST AS WELL. WINDS SHIFT AROUND TO A SOUTH
DIRECTION PRETTY QUICKLY. NAM IS THE MOST AGGRESSIVE BUT IS
SUPPORTED BY OTHER MODEL OUTPUT IN BRINGING STRATUS AND FOG DURING
THE LATE EVENING AND OVERNIGHT HOURS. THIS IS AS THE COLD FRONT
RETREATS BACK AS A WARM FRONT AND ALL THE MODELS ARE VERY SIMILAR
IN DOING IT. MINS WILL PROBABLY BE REACHED IN THE EVENING
ESPECIALLY IN THE WEST AND POSSIBLY IN THE SOUTH AND A NON-DIURNAL
CURVE WILL HAVE TO BE INTRODUCED. BELIEVE MODELS ARE TOO COOL AND
WENT ABOVE THE GUIDANCE.
06Z NAM WAS MUCH MORE ROBUST IN BRINGING IN THE STRATUS AND FOG. NAM
HAS BEEN SHOWING THIS FOR A FEW DAYS PLUS THOSE SOUTH WINDS WILL BE
BLOWING ACROSS A SNOW FIELD. SO EXPANDED THE PATCHY FOG THAT WAS IN
THERE.
FRIDAY/FRIDAY NIGHT...STRATUS AND FOG GET PUSHED EAST PRETTY FAST BY
THE STRENGTHENING DOWNSLOPE WINDS. THERE MAY BE SOME HIGHER LEVEL
CLOUD COVER AROUND. INCOMING SHORTWAVE TROUGH IN NORTHWEST FLOW
ALOFT WILL PUSH A WEAK FRONT OR SURFACE TROUGH THROUGH LATER IN THE
DAY BUT IT LOOKS LIKE WINDS WILL BE FROM A DOWNSLOPE DIRECTION. SO
ENDED UP RAISING THE MAXES A LITTLE.
LEFT FRONT QUADRANT OF JET WILL AFFECT THE NORTHERN PORTION OF THE
AREA DURING THE NIGHT AS WELL AS THE ABOVE MENTIONED SHORTWAVE
TROUGH...WHICH HAPPENS TO BE THE ONE TOPPING THE RIDGE RIGHT NOW
NEAR WESTERN CANADA. ALL MODELS AGREE THAT THIS SYSTEM WILL HAVE
A VERY STRONG PV ANOMALY AS WELL. MODELS DO NOT SHOW A LOT OF
MOISTURE IN THE COLUMN BUT STRENGTH OF SYSTEM SHOULD COMPENSATE FOR
THAT. SO EXPANDED THE SPRINKLES AND FLURRIES OVER A LARGER AREA AND
THROUGH THE EVENING HOURS.
SATURDAY/SATURDAY NIGHT...RIDGING AND DRYING ALOFT PUSH INTO THE
AREA FOR SATURDAY. SO WILL HAVE PLENTY OF SUN ALONG WITH STRONG
DOWNSLOPE WINDS. SO RAISED MAXES MORE AND I MAY NOT BE WARM ENOUGH
AS I BELIEVE MODELS ARE TOO COOL.
.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 246 AM MST THU JAN 31 2013
MODEL AGREEMENT IS FAIRLY GOOD IN THE EXTENDED FORECAST. ALL
SOLUTIONS ARE POINTING TO A TAME WEATHER PATTERN WITHOUT ANY BIG
WEATHER CHANGES OR PRECIPITATION CHANCES. A SYSTEM WILL MOVE ACROSS
THE NORTHERN PLAINS AND GREAT LAKES ON MONDAY...BRINGING ONLY A WIND
SHIFT AND TEMPERATURES A DEGREE OR TWO COOLER. AFTER THAT...A RIDGE
OF HIGH PRESSURE BUILDS BACK IN FROM THE WEST.
TEMPERATURES SHOULD BE WELL ABOVE NORMAL FOR THIS TIME OF YEAR
THROUGHOUT THE EXTENDED FORECAST. HIGHS SHOULD BE IN THE 50S FOR
SUNDAY THROUGH TUESDAY...WITH HIGHS CLIMBING INTO THE 60S BY THE
MIDDLE OF NEXT WEEK. GUIDANCE HAS PULLED BACK SOMEWHAT FOR HIGH
TEMPERATURES ON SUNDAY BUT STILL THINK TEMPERATURES NEARING 60 FOR
EASTERN COLORADO IS NOT OUT OF THE QUESTION.
THE ONLY OTHER CONCERN FOR THE EXTENDED FORECAST WAS LOW
TEMPERATURES. THE INITIALIZATION PROCEDURE INPUT LOW TEMPERATURES
THAT WERE LIKELY TOO WARM. CONSIDERING THE ONGOING DROUGHT
CONDITIONS AND MEX AND ECE GUIDANCE SUGGESTING TEMPERATURES MUCH
LOWER THAN THE INITIALIZATION...HAVE LOWERED LOW TEMPERATURES A
DEGREE OR TWO. GUIDANCE IS ALTERED BY CLIMATOLOGICAL DATA SO THIS
COULD BE THE REASON MEX AND ECE GUIDANCE IS BEING HELD DOWN
SOMEWHAT. HOWEVER...THE HIGHER LOW TEMPS SEEMED A LITTLE
UNREASONABLE WITH CLEAR SKIES AND LIGHT WINDS THROUGHOUT THE
EXTENDED PERIOD.
THANKS TO ALL FOR THE COLLABORATION.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1040 AM MST THU JAN 31 2013
VFR TO MVFR CONDITIONS WILL PERSIST THROUGH THE TAF PERIOD AT BOTH
GLD AND MCK. FOR THE REST OF THE DAY...SOME BREEZY WINDS AND
CLEARING SKIES AT GLD...WHILE CURRENT CLOUDS WILL STICK AROUND AT
MCK. THIS EVENING A BACKDOOR COLD FRONT WILL PUSH FROM NORTHEAST TO
SOUTHWEST...ARRIVING AT MCK AROUND 22Z. THIS WILL SHIFT
WINDS...THOUGH WIND SPEEDS AT BOTH TERMINALS WILL BE LIGHT /LESS
THAN 10KTS/ THROUGHOUT THE OVERNIGHT PERIOD. SOME PATCHY FOG AND LOW
STRATUS CLOUDS ARE EXPECTED...WITH CONDITIONS MAINLY REMAINING MVFR.
BEST CHANCE FOR FOG WILL BE AT GLD...THOUGH IF FOG REACHES MCK IT
MAY STICK AROUND INTO THE MID-MORNING HOURS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...032
SHORT TERM...BULLER
LONG TERM...RRH
AVIATION...JJM
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1040 AM MST THU JAN 31 2013
.SHORT TERM...(TODAY THROUGH SATURDAY NIGHT)
ISSUED AT 412 AM MST THU JAN 31 2013
FORECAST PROBLEMS WILL PROBLEMATIC TEMPERATURE FORECAST INTO TONIGHT
AND HOW MUCH TO WARM UP THE HIGH TEMPERATURES INTO SATURDAY.
SATELLITE SHOWING A BROAD UPPER TROUGH OVER THE TROUGH OVER THE
WESTERN AND CENTRAL PACIFIC WITH A RIDGE ALONG THE WEST COAST OF
NORTH AMERICA. A COUPLE OF SYSTEMS COMING INTO THE RIDGE ARE BEATING
IT DOWN. A STRONG AND COLD SYSTEM IS DIGGING INTO THE NORTH CENTRAL
PORTION OF THE COUNTRY. VERY COLD AIR MASS HAS MOVED FURTHER SOUTH
FROM YESTERDAY AND IS NOT TOO FAR NORTH AND EAST OF OUR AREA.
MODELS INITIALIZED WELL AT JET LEVEL WITH THE CANADIAN...GFS...AND
NAM DOING THE BEST. MODELS INITIALIZED WELL AT MID LEVELS WITH THE
GFS...CANADIAN...AND NAM DOING SLIGHTLY BETTER. LARGER SCALE MODELS
DO NOT HAVE THE BACKDOOR COLD FRONT FAR ENOUGH SOUTH AND WEST BY
06Z...OH SURPRISE. THE RUC HAS CONTINUED TO GET BETTER AS THE
NIGHT HAS PROGRESSED. OUTSIDE OF THE RUC ON THE LOW LEVEL THERMAL
FIELD...THE ECMWF AND GFS WERE DOING A LITTLE BETTER THAN THE UKMET
AND NAM.
TODAY/TONIGHT...VERY THICK CLOUD COVER HAS SPREAD OVER THE AREA
THROUGH THE NIGHT. WHAT THIS HAS DONE HAS PREVENTED ANY FALL OF THE
TEMPERATURES AND IN FACT HAS CAUSED THE TEMPERATURES TO RISE SOME.
NWP OUTPUT MUST BE UNDERDOING THIS CLOUD COVER AND IS TOO COOL WITH
TEMPERATURES. THIS CLOUD COVER IS BEING CAUSED BY STRONG MID TO
UPPER LEVEL JET. SOUNDINGS AND PLAN VIEW RELATIVE HUMIDITY PLOTS SHOW
THIS CLOUD COVER LASTING MOST OF THE DAY...ESPECIALLY IN THE
NORTHEAST PORTION.
BACKDOOR COLD FRONT WITH VERY COLD AIR BEHIND IT HAS BEEN MOVING
STEADILY TOWARD THE AREA THROUGH THE NIGHT AND IS NOT THAT FAR
AWAY. RUC IS CATCHING ONTO THIS AT THIS TIME. INITIALLY WAS GOING TO
CUT HIGH TEMPERATURES FROM GOING FORECAST BUT CLOUD COVER HAS
COMPLICATED THAT. SO WILL BE STARTING MUCH WARMER THAN WHAT MOST OF
THE MODELS SAY. FRONT SAGS ACROSS THE AREA THROUGH THE DAY WITH
SOME LOCATIONS IN THE NORTHEAST HALF TO TWO THIRDS REACHING THEIR
MAX BY 18Z. SO COMBINING REALITY AND THE RUC ADJUSTED MAX
TEMPERATURES UP BUT HAVE EXTREMELY LOW CONFIDENCE ABOUT THIS. DID
NOT GOES AS WARM AS IT BECAUSE OF THE CLOUD COVER. HRRR WOULD
INDICATE HIGH TEMPERATURES ABOUT 10 DEGREES WARMER IN THE SOUTHWEST
PORTION OF THE AREA THAT WHAT I HAVE.
LEFT FRONT QUADRANT OF INCOMING JET WILL CONTINUE TO AFFECT THE
NORTHEAST HALF TO TWO THIRDS OF THE AREA INTO EARLY AFTERNOON.
SEVERAL STATIONS HAVE REPORTED BRIEF PERIODS OF FLURRIES. ALL MODEL
OUTPUT AGREES IN PLACING LIGHT QPF IN THE ABOVE MENTIONED AREA. SREF
PROBABILITIES AGREE WITH THAT. IT MAKES SENSE WITH THE JET...
MESOSCALE FORCING AND LAPSE RATES IN PLACE. HOWEVER...DRIER AIR
IN THE LOWEST LAYERS. SO INTRODUCED SCATTERED FLURRIES THROUGH
MIDDAY WHEN THE FORCING AND MOISTURE LEAVE.
PROBLEMATIC MIN FORECAST AS WELL. WINDS SHIFT AROUND TO A SOUTH
DIRECTION PRETTY QUICKLY. NAM IS THE MOST AGGRESSIVE BUT IS
SUPPORTED BY OTHER MODEL OUTPUT IN BRINGING STRATUS AND FOG DURING
THE LATE EVENING AND OVERNIGHT HOURS. THIS IS AS THE COLD FRONT
RETREATS BACK AS A WARM FRONT AND ALL THE MODELS ARE VERY SIMILAR
IN DOING IT. MINS WILL PROBABLY BE REACHED IN THE EVENING
ESPECIALLY IN THE WEST AND POSSIBLY IN THE SOUTH AND A NON-DIURNAL
CURVE WILL HAVE TO BE INTRODUCED. BELIEVE MODELS ARE TOO COOL AND
WENT ABOVE THE GUIDANCE.
06Z NAM WAS MUCH MORE ROBUST IN BRINGING IN THE STRATUS AND FOG. NAM
HAS BEEN SHOWING THIS FOR A FEW DAYS PLUS THOSE SOUTH WINDS WILL BE
BLOWING ACROSS A SNOW FIELD. SO EXPANDED THE PATCHY FOG THAT WAS IN
THERE.
FRIDAY/FRIDAY NIGHT...STRATUS AND FOG GET PUSHED EAST PRETTY FAST BY
THE STRENGTHENING DOWNSLOPE WINDS. THERE MAY BE SOME HIGHER LEVEL
CLOUD COVER AROUND. INCOMING SHORTWAVE TROUGH IN NORTHWEST FLOW
ALOFT WILL PUSH A WEAK FRONT OR SURFACE TROUGH THROUGH LATER IN THE
DAY BUT IT LOOKS LIKE WINDS WILL BE FROM A DOWNSLOPE DIRECTION. SO
ENDED UP RAISING THE MAXES A LITTLE.
LEFT FRONT QUADRANT OF JET WILL AFFECT THE NORTHERN PORTION OF THE
AREA DURING THE NIGHT AS WELL AS THE ABOVE MENTIONED SHORTWAVE
TROUGH...WHICH HAPPENS TO BE THE ONE TOPPING THE RIDGE RIGHT NOW
NEAR WESTERN CANADA. ALL MODELS AGREE THAT THIS SYSTEM WILL HAVE
A VERY STRONG PV ANOMALY AS WELL. MODELS DO NOT SHOW A LOT OF
MOISTURE IN THE COLUMN BUT STRENGTH OF SYSTEM SHOULD COMPENSATE FOR
THAT. SO EXPANDED THE SPRINKLES AND FLURRIES OVER A LARGER AREA AND
THROUGH THE EVENING HOURS.
SATURDAY/SATURDAY NIGHT...RIDGING AND DRYING ALOFT PUSH INTO THE
AREA FOR SATURDAY. SO WILL HAVE PLENTY OF SUN ALONG WITH STRONG
DOWNSLOPE WINDS. SO RAISED MAXES MORE AND I MAY NOT BE WARM ENOUGH
AS I BELIEVE MODELS ARE TOO COOL.
.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 246 AM MST THU JAN 31 2013
MODEL AGREEMENT IS FAIRLY GOOD IN THE EXTENDED FORECAST. ALL
SOLUTIONS ARE POINTING TO A TAME WEATHER PATTERN WITHOUT ANY BIG
WEATHER CHANGES OR PRECIPITATION CHANCES. A SYSTEM WILL MOVE ACROSS
THE NORTHERN PLAINS AND GREAT LAKES ON MONDAY...BRINGING ONLY A WIND
SHIFT AND TEMPERATURES A DEGREE OR TWO COOLER. AFTER THAT...A RIDGE
OF HIGH PRESSURE BUILDS BACK IN FROM THE WEST.
TEMPERATURES SHOULD BE WELL ABOVE NORMAL FOR THIS TIME OF YEAR
THROUGHOUT THE EXTENDED FORECAST. HIGHS SHOULD BE IN THE 50S FOR
SUNDAY THROUGH TUESDAY...WITH HIGHS CLIMBING INTO THE 60S BY THE
MIDDLE OF NEXT WEEK. GUIDANCE HAS PULLED BACK SOMEWHAT FOR HIGH
TEMPERATURES ON SUNDAY BUT STILL THINK TEMPERATURES NEARING 60 FOR
EASTERN COLORADO IS NOT OUT OF THE QUESTION.
THE ONLY OTHER CONCERN FOR THE EXTENDED FORECAST WAS LOW
TEMPERATURES. THE INITIALIZATION PROCEDURE INPUT LOW TEMPERATURES
THAT WERE LIKELY TOO WARM. CONSIDERING THE ONGOING DROUGHT
CONDITIONS AND MEX AND ECE GUIDANCE SUGGESTING TEMPERATURES MUCH
LOWER THAN THE INITIALIZATION...HAVE LOWERED LOW TEMPERATURES A
DEGREE OR TWO. GUIDANCE IS ALTERED BY CLIMATOLOGICAL DATA SO THIS
COULD BE THE REASON MEX AND ECE GUIDANCE IS BEING HELD DOWN
SOMEWHAT. HOWEVER...THE HIGHER LOW TEMPS SEEMED A LITTLE
UNREASONABLE WITH CLEAR SKIES AND LIGHT WINDS THROUGHOUT THE
EXTENDED PERIOD.
THANKS TO ALL FOR THE COLLABORATION.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1040 AM MST THU JAN 31 2013
VFR TO MVFR CONDITIONS WILL PERSIST THROUGH THE TAF PERIOD AT BOTH
GLD AND MCK. FOR THE REST OF THE DAY...SOME BREEZY WINDS AND
CLEARING SKIES AT GLD...WHILE CURRENT CLOUDS WILL STICK AROUND AT
MCK. THIS EVENING A BACKDOOR COLD FRONT WILL PUSH FROM NORTHEAST TO
SOUTHWEST...ARRIVING AT MCK AROUND 22Z. THIS WILL SHIFT
WINDS...THOUGH WIND SPEEDS AT BOTH TERMINALS WILL BE LIGHT /LESS
THAN 10KTS/ THROUGHOUT THE OVERNIGHT PERIOD. SOME PATCHY FOG AND LOW
STRATUS CLOUDS ARE EXPECTED...WITH CONDITIONS MAINLY REMAINING MVFR.
BEST CHANCE FOR FOG WILL BE AT GLD...THOUGH IF FOG REACHES MCK IT
MAY STICK AROUND INTO THE MID-MORNING HOURS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...BULLER
LONG TERM...RRH
AVIATION...JJM
AREA FORECAST DISCUSSION
NWS PADUCAH KY
339 PM CST THU JAN 31 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 315 PM CST THU JAN 31 2013
A STRONG ARCTIC FRONT IS COMBINING WITH AN UPPER LEVEL IMPULSE
SHOOTING QUICKLY EASTWARD TOWARDS THE REGION TO PRODUCE BANDS OF
LOCALLY HEAVY SNOWS ACROSS MISSOURI THIS AFTERNOON. MESO
MODELS...ESP THE RUC...AS WELL THE 12Z GFS TO A LESSER EXTENT ARE
CATCHING ONTO THIS. THE RUC BRINGS THE BANDING PRECIP...WHICH MAY
BEGIN BRIEFLY AS LIGHT RAIN...INTO SOUTHEAST MISSOURI AND SOUTHERN
ILLINOIS DURING THE MID TO LATE AFTERNOON HOURS IN THE POST
FRONTAL ENVIRONMENT.
THIS SNOW COULD QUICKLY BECOME HEAVY AT TIMES IN E TO W ORIENTED
BANDS ACROSS THE REGION. THIS AREA OF PRECIPITATION WILL RAPIDLY
MOVE EAST INTO ACROSS THE REMAINDER OF THE REGION EARLY TONIGHT.
THE SNOW WILL LIKELY TAPER OFF JUST AS QUICKLY AS IT BEGAN OVER
SOUTHEAST MISSOURI EARLY TONIGHT...THEN END OVER THE REST OF THE
REGION BY AROUND MIDNIGHT AS THE IMPULSE TRAVELS OFF TO THE EAST
ON THE NORTH SIDE OF THE COLD FRONT.
THE MAIN IMPACT WILL COME WITH BURSTS OF LOCALLY HEAVY SNOW IN
EAST TO WEST BANDING PRECIPITATION. WHERE...AND HOW NARROW OR
THICK THESE BANDS OF SNOW BECOME WILL DETERMINE HOW MUCH SNOW A
GIVEN LOCATION RECEIVES. AT THIS TIME...IT SEEMS LIKE MUCH OF THE
ADVISORY AREA WILL SEE UP TO A QUICK INCH OR SO OF SNOW.
HOWEVER...THERE WILL LIKELY BE LOCALLY HEAVIER BANDS THAT PRODUCE
A QUICK 2 TO 3 INCHES OF SNOW. MOTORISTS SHOULD BE PREPARED FOR
RAPIDLY FLUCTUATING VISIBILITIES TO UNDER A QUARTER MILE AT TIMES.
OTHER IMPACTS INCLUDE THE FACT THAT MUCH OF THE SNOW WILL OCCUR
DURING INCREASED TRAFFIC BETWEEN 4 PM AND 7 PM...ESPECIALLY IN
SOUTHEAST MISSOURI...SOUTHERN ILLINOIS AND THE WESTERN TIP OF
KENTUCKY AND SOUTHWEST INDIANA.
TRUE ARCTIC BLAST...THOUGH FAIRLY BRIEF...WILL FOLLOW QUICKLY IN
THE WAKE OF THIS SYSTEM. SHOULD SEE TEMPS STAY BELOW FREEZING ALL
DAY FRIDAY...WELL BELOW FREEZING IF WE GET A FRESH LAYER OF
SNOWFALL. SAME WITH FRI NIGHT. IF ANY SNOW IS ON THE
GROUND...TEMPS WILL LIKELY CHALLENGE SINGLE DIGITS IN THOSE
LOCATIONS.
WEAK DISTURBANCE AND WARM FRONT WILL LIKE PASS NEAR THE REGION
SAT. RIGHT NOW LOOKS LIKE A NON EVENT...UNLESS THE VERY LIGHT
PRECIP BEGINS EARLY ENOUGH SAT AM. IF SO...THEN A LITTLE LIGHT
SNOW...SLEET OF FREEZING RAIN WOULD BE POSSIBLE BEFORE SFC TEMPS
WARM ABOVE FREEZING.
.LONG TERM...(SUNDAY THROUGH THURSDAY)
ISSUED AT 315 PM CST THU JAN 31 2013
A FAIRLY ACTIVE PATTERN SETTING UP FOR NEXT WEEK...WITH SEVERAL
WEATHER SYSTEMS TO KEEP AN EYE ON. HOWEVER...THEY ARE WEAK
SYSTEMS...EXCEPT FOR THE ONE SLATED FOR WED NIGHT/THURSDAY...WHICH
HAS THE BEST POTENTIAL RIGHT NOW OF BRINGING MORE WIDESPREAD
PRECIPITATION.
ON SUNDAY...WE SHOULD SEE SFC HIGH PRESSURE SLOWLY OOZE INTO THE
REGION...WITH NORTHWEST FLOW ALOFT. MODELS DIVERGE AFTER THIS...AS
THE 00Z ECMWF SHOVES THE SFC HIGH EAST SUNDAY NIGHT AS ANOTHER
FRONTAL SYSTEM BARRELS DOWN FROM THE NORTHWEST. A WEAK WAVE ALOFT
ACCOMPANIES THIS FEATURE BUT MOST OF THE ENERGY STAYS TO OUR
SOUTHWEST. THE 06Z ECMWF SHOWED A GLANCING SHOT FOR PRECIP ACROSS
SE MO/SW KY ON MONDAY...BUT THE 12Z RUN IS MUCH MORE AGGRESSIVE AND
PAINTS QPF OVER THE ENTIRE AREA. THE GFS IS MUCH SLOWER WITH THE
PROGRESSION OF THIS SYSTEM WITH ITS 06Z RUN...AND SHOWS THE SFC HIGH
RETREATING MONDAY MORNING WITH THE FRONTAL SYSTEM APPROACHING LATER
IN THE DAY...BUT WEAKENING SO MUCH THAT IT REALLY HAS LITTLE IMPACT
ON OUR AREA. THE 12Z GFS RUN IS MORE IN LINE WITH THE TIMING OF THE
00Z ECMWF NOW...BUT STILL SPLITS OUR AREA WHEN IT COMES TO
RAIN CHANCES...WITH THE MAIN PRECIP SKIRTING BY TO OUR
NORTH AND SOUTH. WILL START OUT WITH A SLIGHT CHANCE ACROSS SOUTHERN
MO AND SW KY.
ANOTHER LOW PRESSURE SYSTEM COMES DOWN OUT OF THE NORTHERN PLAINS
AND INTO THE MIDWEST LATE MONDAY NIGHT AND INTO TUESDAY.
AGAIN...MODELS DO NOT AGREE ON THIS SYSTEM EITHER...WITH THE ECMWF
MUCH DEEPER WITH THE UPPER TROUGH AND HENCE...IT INDICATES THAT SOME
PRECIP CHANCES MAY FLIRT WITH THE WABASH VALLEY OF SE IL AND THE EVV
TRI STATE REGION ON TUESDAY. SO EITHER WAY...IT DOES NOT LOOK LIKE
TOO BIG A DEAL SINCE MOST OF THE MOISTURE STAYS FURTHER NORTH AND
EAST OF THE AREA. MODEL SOUNDINGS INDICATE THAT THE LOWEST FEW
THOUSAND FT WILL BE WARM ENOUGH THAT EVEN IF IT DID PRECIPITATE...IT
SHOULD BE LIQUID. BUT THERE IS QUITE A DIFFERENCE IN LOW LEVEL TEMPS
BTWN THE GFS AND ECWMF DUE TO THE DEGREE OF THE AMPLITUDE OF THE
TROUGH COMING THROUGH.
TUESDAY NIGHT AND WEDNESDAY...HIGH PRESSURE WILL BUILD IN BEHIND THE
FRONT...BUT WILL QUICKLY MOVE EAST WED NIGHT. OUR NEXT SYSTEM COULD
IMPACT US AS EARLY AS LATE WED...OR HOLD OFF UNTIL THURSDAY.
HOWEVER...THE SIGNAL IS FAIRLY STRONG THAT WE WILL SEE SOME
PRECIPITATION ON THURSDAY...WITH SUPPORT OF THE GFS ENSEMBLES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1122 AM CST THU JAN 31 2013
BKN VFR DECK AT KEVV/KOWB ALONG WITH SOME MID CLOUDS AROUND. SCT
TO MID CLOUDS POSSIBLE ELSEWHERE AS WELL. ARCTIC COLD FRONT OFF
TO THE NORTHWEST WILL MOVE INTO THE AREA LATER THIS AFTERNOON.
GUSTY WSW WINDS AHEAD OF IT. HAVE A -SN CHANCE FROM 21Z- 01Z WITH
THE FRONTAL PASSAGE. CLEARING AFTER THAT...WITH GUSTY NW WINDS
POST FRONTAL...WHICH WILL SLACKEN BY 12Z.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR
ILZ081>094.
MO...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR MOZ076-
086-087-100-107>112-114.
IN...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR INZ081-
082-085>088.
KY...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR
KYZ001>022.
&&
$$
SHORT TERM...MEFFERT
LONG TERM....CW
AVIATION...CW
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
240 PM EST THU JAN 31 2013
.SYNOPSIS...
COLDER AIR WORKING INTO THE AREA BEHIND A STRONG COLD FRONT WILL
PRODUCE STRONG GUSTY WINDS TODAY...IN ADDITION TO LAKE EFFECT
SNOWS DOWNWIND OF LAKES ERIE AND ONTARIO. BELOW NORMAL
TEMPERATURES AND SCATTERED SHOW SHOWERS WILL CONTINUE INTO THE
WEEKEND...DUE TO A COMBINATION OF LAKE EFFECT SNOW SHOWERS AND
WEAK UPPER LEVEL DISTURBANCES.
&&
.NEAR TERM /THROUGH TONIGHT/...
12 NOON UPDATE... WE`VE PUSHED BACK THE START TIME OF THE LES WRNG
BY A FEW HRS IN NRN ONEIDA (NOW 21Z). BASED ON THE LATEST KBUF VWP
(STILL A 260 FLOW OVER A DEEP LYR)...AND OVERALL RADAR
PRESENTATION...WE THINK THE ONSET OF THE +SN IN NRN ONEIDA WILL BE
SOMEWHAT DELAYED FROM OUR EARLIER FCST. THE AMTS STILL LOOK
REPRESENTATIVE...AS PARAMETERS SEEM FAVORABLE FOR FAIRLY INTENSE
RATES...ONCE THE SNOW DOES FINALLY MOVE IN.
10 AM UPDATE... OUR CURRENT FCST IS IN EXCELLENT SHAPE ATTM...SO
ONLY COSMETIC CHGS WERE MADE.
AS STG CAA CONTS TO FILTER ACRS THE FA LATE THIS MRNG...LES BANDS
ARE TRYING TO ORGANIZE OFF BOTH LKS ERIE AND ONT. AS JUDGED FROM
THE 12Z RAOBS AT BUF/DTX...THE MIXED LYR EXTENDS UP TO ABT 750
MB...WITH A FAIR MOISTURE SUPPLY UNDERNEATH THE BASE OF THE
INVERSION. GIVEN CONTD CYCLONIC FLOW...FURTHER COOLING WITH
TIME...AND IF ANYTHING...A DEEPENING OF THE SYNOPTIC MOISTURE THIS
AFTN AND EVE...THERE`S NO REASON NOT TO EXPECT THE DVLPMT OF
FAIRLY STG LAKE-EFFECT PLUMES OFF BOTH LKS.
IN-HOUSE CAPE/SHEAR NOMOGRAM SHOWS ENUF OVER-LAND INSTAB THROUGH
THIS EVE (00-03Z)...SO THAT THE BANDS MAY TAKE ON SOMEWHAT OF A CELLULAR
APPEARANCE...AT TIMES. HOWEVER...ORGANIZATION IS NOT LIKELY TO BE
SERIOUSLY COMPROMISED. ALSO...THE CSTAR-DERIVED INLAND EXTENT
APPLICATION DEPICTS A FAIRLY DEEP INLAND PENETRATION THROUGHOUT
THE EVE HRS...AT LEAST...WITH A GOOD UPSTREAM CONNECTION TO
HURON/NRN LK MI/SUPERIOR...AND ALSO STG 0-1 KM SPEED SHEAR. THIS
ALSO SEEMS WELL SUPPORTED BY SIM REFLECTIVITY PRESENTATIONS FROM
THE NAM12...LOCAL ARW...AND HRRR MODELS.
BOTTOM LN...THINGS APPEAR WELL ON TRACK FOR THE LES WRNG IN NRN
ONEIDA...WITH A PD OF VERY HVY SNOW ANTICIPATED...FROM ROUGHLY
22-06Z. GIVEN DEEP MOISTURE...AND EXCELLENT CRYSTAL GROWTH
PARAMETERS...2-3"/HR RATES ARE NOT OUT OF THE QUESTION. ELSEWHERE
(ONONDAGA/MADISON/SRN ONEIDA)...DESPITE SOME ANTICIPATED
WEAKENING LTR TNT...AS THE BAND DROPS SWD...THERE MAY BE ENUF
RESIDUAL INTENSITY FOR ADVSY-LVL ACCUMS. WE`LL RE-VISIT THIS SITN
EARLY THIS AFTN.
ACRS THE TWIN TIERS...SOME CONVECTIVE SHSN ARE LIKELY TO FORM BY
MID TO LATE AFTN...AIDED A BIT BY ADVECTION OF MOISTURE FROM LKS
ERIE AND SRN MI IN STG WRLY FLOW. OVERALL...THOUGH...THE NATURE OF
THEM WILL REMAIN SCTD.
AS FOR THE WINDS...THEY`RE LIKELY TO BE AT THEIR PEAK THROUGH ABT
18Z...WITH A SLOW DIMINISHING TREND THEREAFTER...AS JUDGED FROM
ISALLOBARIC AND MOMENTUM TRANSFER PROGS.
A STEADY OR SLOWLY FALLING TEMP TREND IS WELL HANDLED IN THE
GRIDS...SO ONLY VERY MINOR TWEAKS WERE NEEDED.
PREV DISC... 620 AM...WILL DROP THE FLOOD WATCH FOR ERN ZONES AS
STEADY RAIN IS MOVG OUT. OTRW JUST MINOR NEAR TERM TWEEKS WITH NO
SIG CHGS TO FCST. PREV BLO...
450 AM...DROPPED FLOOD WATCH FOR THE CNTRL SRN TIER AND PORTIONS
OF THE FINGER LAKES AS BACK EDGE OF STEADIER RAIN HAS EXITED THIS
RGN. MAY STILL SEE SOME MINOR FLOODING DUE TO RUNOFF BUT FLS`S
HANDLING THAT. CONVECTIVE FNTL LINE PRODUCED WIND GUSTS IN THE
40-50 MPH RECENTLY AT SYR/BGM. SYNOPTIC SCALE WINDS WILL BE
INCRSNG RAPIDLY LATER THIS MRNG ALL AREAS. PREV BLO...
BACK EDGE OF AREA OF STEADY RAIN AREA MOVING INTO WRN ZONES AS OF
315 AM...CLOSE TO THE PSN OF THE SFC CDFNT...AND WILL CONTINUE IT`S EWD
PROGRESS THROUGH THE EARLY MRNG HRS. SOME OF THE RAIN MAY MIX
BRIEFLY WITH SNOW BEFORE TAPERING OFF THIS MRNG. FLOOD WATCH
REMAINS ON EFFECT...WE HAVE ISSUED SOME FLS`S THUS FAR AND WILL
CONTINUE TO MONITOR CAREFULLY.
MAIN ISSUE TDA WILL BE THE STRONG WINDS DVLPNG THIS MRNG AND
CONTINUING INTO THE AFTN HRS. BASED ON OUR SUSTAINED AND PEAK WIND
GRIDS...WE ADDED STEUBEN...YATES AND SENECA COUNTIES INTO THE
WARNING.
SCATTERED SNOW SHOWERS ARE XPCTD TDA...MAINLY DUE TO LAKE
INFLUENCES. WE COULD SEE -SHSN OFF LAKE ERIE ACRS PORTIONS OF THE
TWIN TIERS THIS AFTN/EVNG. POTNL FOR 2-4 INCHES ACRS PORTIONS OF
WRN STEUBEN TNGT. AFTN SHIFT CAN RE-ASSESS AND DETERMINE IF A LOW
END ADVISORY IS NEEDED HERE.
AS FOR THE NRN ONEIDA LES EVENT...THIS EVENT APPEARS TO BE SIMILAR
TO LAST WEEKS. THE ARW PERFORMED WELL IN THAT CASE...AND THIS
MRNG`S RUC ALSO SHOWS GOOD AGREEMENT EARLY ON IN THE PD. IT
APPEARS THAT THE BAND WILL NOT MAKE A MOVE INTO NRN ONEIDA UNTIL
LATE THIS AFTN...PERSISTING OVER THAT AREA TIL ARND 06Z BEFORE
DROPPING SWD AS FLOW BCMS MORE WNWLY. AS THIS OCCURS...MESO MDLS
SHOW THE BAND OVER LAKE ONTARIO DROPPING TO A PSN NEAR/ALONG THE
SRN SHORE OF LAKE ONTARIO LATE TNGT/TWDS DAYBREAK. THIS IS WHAT
OCCURRED WITH THE LAST BAND...AND RESULTED IN RAPID WEAKENING OF
THE BAND OVER THE BGM CWA DUE (AT LEAST IN PART) TO THE LOSS OF
OVER-LAKE TRAJECTORY. THIS IS ALSO HINTED AT IN THE MESO MDLS FRI
MRNG. FOR NOW WE HAVE THE BAND DROPPING SWD INTO ONON/MAD IN THE
09-12Z TIME FRAME...WITH POTNL FOR LOW END ADVISORY ACCUMS MAINLY
OVER NW ONON. GIVEN THE NUMEROUS HEADLINES ALREADY IN EFFECT AND
THE FACT WE HAVE SOME TIME TO TAKE A CLOSER LOOK AT THIS...WE WILL
JUST MENTION THE POTNL IN THE HWO AND LET THE DAY SHIFT ISSUE
HEADLINES FOR THIS EVENT IF NEEDED.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
A COUPLE OF CLIPPER-TYPE SYSTEMS WILL AFFECT THIS WEEKEND...WITH
SCATTERED SNOW SHOWERS. A MORE WDSPRD AREA OF LGT SNOW COULD DVLP
IN THE WARM ADVECTION PTRN AHEAD OF THE CLIPPER APRCHNG SAT NGT.
IN GNRL...CHC POPS FOR -SHSN AND BLO NORMAL TEMPS.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
230 PM UPDATE...
LK EFFECT SNOW WL START OFF THE LONG TERM AS SYSTEM EXITS OFF OF THE
EAST COAST. NW FLOW WL BRING CLD AIR ACRS THE LKS ALONG WITH NEAR
SEASONAL TEMPS. CLIPPER TYPE LOW WL MV THRU THE UPR MIDWEST AND
MID-ATLANTIC SPREADING LIGHT SNOW INTO THE REGION ON TUESDAY. 12Z
MED RANGE GUIDANCE SHOWS SLIGHT DISCREPANCIES IN HOW FAR NORTH
CLIPPER TRACKS ON MON NGT INTO TUESDAY. WITH GFS BEING FURTHER NORTH
AND EC SUPPRESSED FURTHER TO THE SOUTH, HV SIDED WITH HPC GUIDANCE
WITH LOW-MID RANGE CHC POPS FOR THIS TIME PD. SYSTEM WL SKIRT TO THE
SOUTH AS HIPRES WL BUILD IN FM THE NORTH. HV ASSIGNED LOCHC POPS TO
THE ENTIRE AREA FOR TUE NGT THEN THINKING IT WL TRANSITION TO A LGT
LES EVENT ACRS FINGER LKS REGION WITH JUST FLURRIES ELSEWHERE. SFC
HIPRES WL BUILD IN WED NGT AND THURSDAY. L/WV TROF FCST TO DROP INTO
THE PLAINS TWD THE END OF THE PD WITH LIGHT SNOW SPREADING INTO CWA
BY 12Z FRIDAY.
&&
.AVIATION /20Z THURSDAY THROUGH TUESDAY/...
18Z UPDATE...
SNOW HAS MOVED INTO ALL TERMINALS BEHIND COLD FRONT. WITH
SCATTERED SNOW SHOWERS, CONDS WILL RANGE FROM VFR TO MVFR THOUGH
AN OCCASIONAL IFR CANNOT BE RULED OUT. AS LAKE EFFECT BAND GETS
ORGANIZED IFR VSBYS WILL MOVE INTO KRME AFTER 03Z AND KSYR AFTER
09Z. AT KELM AND KITH EXPECT MVFR CONDS TONIGHT WITH FLOW OFF OF
LAKE ERIE THOUGH KBGM AND KAVP SHOULD REMAIN LOW VFR.
WINDS OUT OF THE SOUTHWEST THIS AFTERNOON AROUND 25KTS WILL GUST
TO 30-40KTS. WINDS WILL REMAIN GUSTY NEXT 24 HOURS THOUGH GUSTS
WILL LESSEN TO AROUND 25KTS AND GRADUALLY SWITCH AROUND TO A MORE
WEST-NORTHWEST DIRECTION.
.OUTLOOK...
SAT/SAT NGT...MVFR-IFR FROM LAKE -SHSN IN CENTRAL NY.
SUN...A COLD FRONT WITH POSSIBLE MVFR AND IFR SNOW
SUN NGT-MON...MORE MVFR/IFR LAKE -SHSN MAINLY CENTRAL NY.
TUE...MVFR/IFR IN LIGHT SNOW AT ALL TERMINALS.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...WIND ADVISORY UNTIL 7 PM EST THIS EVENING FOR PAZ038>040-043-
044-047-048-072.
NY...WIND ADVISORY UNTIL 7 PM EST THIS EVENING FOR NYZ023>025-044-
045-055-056-062.
HIGH WIND WARNING UNTIL 7 PM EST THIS EVENING FOR NYZ009-
015>018-022-036-037-046-057.
LAKE EFFECT SNOW WARNING UNTIL 7 AM EST FRIDAY FOR NYZ009.
LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST FRIDAY FOR NYZ022.
LAKE EFFECT SNOW ADVISORY FROM 4 AM TO 7 PM EST FRIDAY FOR
NYZ018-036-037.
&&
$$
SYNOPSIS...
NEAR TERM...MLJ
SHORT TERM...
LONG TERM...PVN
AVIATION...PVN
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
123 PM EST THU JAN 31 2013
.SYNOPSIS...
COLDER AIR WORKING INTO THE AREA BEHIND A STRONG COLD FRONT WILL
PRODUCE STRONG GUSTY WINDS TODAY...IN ADDITION TO LAKE EFFECT
SNOWS DOWNWIND OF LAKES ERIE AND ONTARIO. BELOW NORMAL
TEMPERATURES AND SCATTERED SHOW SHOWERS WILL CONTINUE INTO THE
WEEKEND...DUE TO A COMBINATION OF LAKE EFFECT SNOW SHOWERS AND
WEAK UPPER LEVEL DISTURBANCES.
&&
.NEAR TERM /THROUGH TONIGHT/...
12 NOON UPDATE... WE`VE PUSHED BACK THE START TIME OF THE LES WRNG
BY A FEW HRS IN NRN ONEIDA (NOW 21Z). BASED ON THE LATEST KBUF VWP
(STILL A 260 FLOW OVER A DEEP LYR)...AND OVERALL RADAR
PRESENTATION...WE THINK THE ONSET OF THE +SN IN NRN ONEIDA WILL BE
SOMEWHAT DELAYED FROM OUR EARLIER FCST. THE AMTS STILL LOOK
REPRESENTATIVE...AS PARAMETERS SEEM FAVORABLE FOR FAIRLY INTENSE
RATES...ONCE THE SNOW DOES FINALLY MOVE IN.
10 AM UPDATE... OUR CURRENT FCST IS IN EXCELLENT SHAPE ATTM...SO
ONLY COSMETIC CHGS WERE MADE.
AS STG CAA CONTS TO FILTER ACRS THE FA LATE THIS MRNG...LES BANDS
ARE TRYING TO ORGANIZE OFF BOTH LKS ERIE AND ONT. AS JUDGED FROM
THE 12Z RAOBS AT BUF/DTX...THE MIXED LYR EXTENDS UP TO ABT 750
MB...WITH A FAIR MOISTURE SUPPLY UNDERNEATH THE BASE OF THE
INVERSION. GIVEN CONTD CYCLONIC FLOW...FURTHER COOLING WITH
TIME...AND IF ANYTHING...A DEEPENING OF THE SYNOPTIC MOISTURE THIS
AFTN AND EVE...THERE`S NO REASON NOT TO EXPECT THE DVLPMT OF
FAIRLY STG LAKE-EFFECT PLUMES OFF BOTH LKS.
IN-HOUSE CAPE/SHEAR NOMOGRAM SHOWS ENUF OVER-LAND INSTAB THROUGH
THIS EVE (00-03Z)...SO THAT THE BANDS MAY TAKE ON SOMEWHAT OF A CELLULAR
APPEARANCE...AT TIMES. HOWEVER...ORGANIZATION IS NOT LIKELY TO BE
SERIOUSLY COMPROMISED. ALSO...THE CSTAR-DERIVED INLAND EXTENT
APPLICATION DEPICTS A FAIRLY DEEP INLAND PENETRATION THROUGHOUT
THE EVE HRS...AT LEAST...WITH A GOOD UPSTREAM CONNECTION TO
HURON/NRN LK MI/SUPERIOR...AND ALSO STG 0-1 KM SPEED SHEAR. THIS
ALSO SEEMS WELL SUPPORTED BY SIM REFLECTIVITY PRESENTATIONS FROM
THE NAM12...LOCAL ARW...AND HRRR MODELS.
BOTTOM LN...THINGS APPEAR WELL ON TRACK FOR THE LES WRNG IN NRN
ONEIDA...WITH A PD OF VERY HVY SNOW ANTICIPATED...FROM ROUGHLY
22-06Z. GIVEN DEEP MOISTURE...AND EXCELLENT CRYSTAL GROWTH
PARAMETERS...2-3"/HR RATES ARE NOT OUT OF THE QUESTION. ELSEWHERE
(ONONDAGA/MADISON/SRN ONEIDA)...DESPITE SOME ANTICIPATED
WEAKENING LTR TNT...AS THE BAND DROPS SWD...THERE MAY BE ENUF
RESIDUAL INTENSITY FOR ADVSY-LVL ACCUMS. WE`LL RE-VISIT THIS SITN
EARLY THIS AFTN.
ACRS THE TWIN TIERS...SOME CONVECTIVE SHSN ARE LIKELY TO FORM BY
MID TO LATE AFTN...AIDED A BIT BY ADVECTION OF MOISTURE FROM LKS
ERIE AND SRN MI IN STG WRLY FLOW. OVERALL...THOUGH...THE NATURE OF
THEM WILL REMAIN SCTD.
AS FOR THE WINDS...THEY`RE LIKELY TO BE AT THEIR PEAK THROUGH ABT
18Z...WITH A SLOW DIMINISHING TREND THEREAFTER...AS JUDGED FROM
ISALLOBARIC AND MOMENTUM TRANSFER PROGS.
A STEADY OR SLOWLY FALLING TEMP TREND IS WELL HANDLED IN THE
GRIDS...SO ONLY VERY MINOR TWEAKS WERE NEEDED.
PREV DISC... 620 AM...WILL DROP THE FLOOD WATCH FOR ERN ZONES AS
STEADY RAIN IS MOVG OUT. OTRW JUST MINOR NEAR TERM TWEEKS WITH NO
SIG CHGS TO FCST. PREV BLO...
450 AM...DROPPED FLOOD WATCH FOR THE CNTRL SRN TIER AND PORTIONS
OF THE FINGER LAKES AS BACK EDGE OF STEADIER RAIN HAS EXITED THIS
RGN. MAY STILL SEE SOME MINOR FLOODING DUE TO RUNOFF BUT FLS`S
HANDLING THAT. CONVECTIVE FNTL LINE PRODUCED WIND GUSTS IN THE
40-50 MPH RECENTLY AT SYR/BGM. SYNOPTIC SCALE WINDS WILL BE
INCRSNG RAPIDLY LATER THIS MRNG ALL AREAS. PREV BLO...
BACK EDGE OF AREA OF STEADY RAIN AREA MOVING INTO WRN ZONES AS OF
315 AM...CLOSE TO THE PSN OF THE SFC CDFNT...AND WILL CONTINUE IT`S EWD
PROGRESS THROUGH THE EARLY MRNG HRS. SOME OF THE RAIN MAY MIX
BRIEFLY WITH SNOW BEFORE TAPERING OFF THIS MRNG. FLOOD WATCH
REMAINS ON EFFECT...WE HAVE ISSUED SOME FLS`S THUS FAR AND WILL
CONTINUE TO MONITOR CAREFULLY.
MAIN ISSUE TDA WILL BE THE STRONG WINDS DVLPNG THIS MRNG AND
CONTINUING INTO THE AFTN HRS. BASED ON OUR SUSTAINED AND PEAK WIND
GRIDS...WE ADDED STEUBEN...YATES AND SENECA COUNTIES INTO THE
WARNING.
SCATTERED SNOW SHOWERS ARE XPCTD TDA...MAINLY DUE TO LAKE
INFLUENCES. WE COULD SEE -SHSN OFF LAKE ERIE ACRS PORTIONS OF THE
TWIN TIERS THIS AFTN/EVNG. POTNL FOR 2-4 INCHES ACRS PORTIONS OF
WRN STEUBEN TNGT. AFTN SHIFT CAN RE-ASSESS AND DETERMINE IF A LOW
END ADVISORY IS NEEDED HERE.
AS FOR THE NRN ONEIDA LES EVENT...THIS EVENT APPEARS TO BE SIMILAR
TO LAST WEEKS. THE ARW PERFORMED WELL IN THAT CASE...AND THIS
MRNG`S RUC ALSO SHOWS GOOD AGREEMENT EARLY ON IN THE PD. IT
APPEARS THAT THE BAND WILL NOT MAKE A MOVE INTO NRN ONEIDA UNTIL
LATE THIS AFTN...PERSISTING OVER THAT AREA TIL ARND 06Z BEFORE
DROPPING SWD AS FLOW BCMS MORE WNWLY. AS THIS OCCURS...MESO MDLS
SHOW THE BAND OVER LAKE ONTARIO DROPPING TO A PSN NEAR/ALONG THE
SRN SHORE OF LAKE ONTARIO LATE TNGT/TWDS DAYBREAK. THIS IS WHAT
OCCURRED WITH THE LAST BAND...AND RESULTED IN RAPID WEAKENING OF
THE BAND OVER THE BGM CWA DUE (AT LEAST IN PART) TO THE LOSS OF
OVER-LAKE TRAJECTORY. THIS IS ALSO HINTED AT IN THE MESO MDLS FRI
MRNG. FOR NOW WE HAVE THE BAND DROPPING SWD INTO ONON/MAD IN THE
09-12Z TIME FRAME...WITH POTNL FOR LOW END ADVISORY ACCUMS MAINLY
OVER NW ONON. GIVEN THE NUMEROUS HEADLINES ALREADY IN EFFECT AND
THE FACT WE HAVE SOME TIME TO TAKE A CLOSER LOOK AT THIS...WE WILL
JUST MENTION THE POTNL IN THE HWO AND LET THE DAY SHIFT ISSUE
HEADLINES FOR THIS EVENT IF NEEDED.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
A COUPLE OF CLIPPER-TYPE SYSTEMS WILL AFFECT THIS WEEKEND...WITH
SCATTERED SNOW SHOWERS. A MORE WDSPRD AREA OF LGT SNOW COULD DVLP
IN THE WARM ADVECTION PTRN AHEAD OF THE CLIPPER APRCHNG SAT NGT.
IN GNRL...CHC POPS FOR -SHSN AND BLO NORMAL TEMPS.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
GRIDS WERE ADJUSTED SOME TO ACCOUNT FOR LATEST HPC GUIDANCE AND
GFS/ECMWF MODELS. NO BIG CHANGE TO GOING FORECAST OVERALL...BUT I
DID UPGRADE POPS INTO LIKELY CATEGORY FOR CENTRAL NY AND AT LEAST
HIGHER CHANCE FOR NORTHEAST PA SUNDAY WITH FAIR AGREEMENT ON BEING
INVOLVED IN MERGER BETWEEN DEVELOPING COASTAL LOW AND INCOMING
NORTHERN STREAM SYSTEM/CLIPPER. COULD EASILY RESULT IN LIGHT
COATING OF SNOW. ANOTHER WEAK CLIPPER CONTINUES TO LOOK POSSIBLE
MONDAY NIGHT/TUESDAY.
PREVIOUS DISCUSSION...
FOLLOWED HPC GUIDANCE. MODELS ARE SIMILAR WITH NO LARGE STORMS.
REMAIN UNDER A NORTHEAST US UPPER LEVEL TROF. SEASONABLE WEATHER
WITH WEAK LOW PRESSURE SYSTEMS FOLLOWED BY LAKE EFFECT. ALL PRECIP
WILL BE SNOW WITH HIGHS AROUND 30 AND LOWS IN THE TEENS. THE WEAK
SYSTEMS GO THROUGH SUNDAY AND MONDAY NIGHT...WITH LAKE EFFECT ON
THE OTHER DAYS. COULD BE A 12 HOUR DRY BREAK BETWEEN SYSTEMS WITH
WEAK HIGH PRESSURE MON AFTN.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
18Z UPDATE...
SNOW HAS MOVED INTO ALL TERMINALS BEHIND COLD FRONT. WITH
SCATTERED SNOW SHOWERS, CONDS WILL RANGE FROM VFR TO MVFR THOUGH
AN OCCASIONAL IFR CANNOT BE RULED OUT. AS LAKE EFFECT BAND GETS
ORGANIZED IFR VSBYS WILL MOVE INTO KRME AFTER 03Z AND KSYR AFTER
09Z. AT KELM AND KITH EXPECT MVFR CONDS TONIGHT WITH FLOW OFF OF
LAKE ERIE THOUGH KBGM AND KAVP SHOULD REMAIN LOW VFR.
WINDS OUT OF THE SOUTHWEST THIS AFTERNOON AROUND 25KTS WILL GUST
TO 30-40KTS. WINDS WILL REMAIN GUSTY NEXT 24 HOURS THOUGH GUSTS
WILL LESSEN TO AROUND 25KTS AND GRADUALLY SWITCH AROUND TO A MORE
WEST-NORTHWEST DIRECTION.
.OUTLOOK...
SAT/SAT NGT...MVFR-IFR FROM LAKE -SHSN IN CENTRAL NY.
SUN...A COLD FRONT WITH POSSIBLE MVFR AND IFR SNOW
SUN NGT-MON...MORE MVFR/IFR LAKE -SHSN MAINLY CENTRAL NY.
TUE...MVFR/IFR IN LIGHT SNOW AT ALL TERMINALS.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...WIND ADVISORY UNTIL 7 PM EST THIS EVENING FOR PAZ038>040-043-
044-047-048-072.
NY...WIND ADVISORY UNTIL 7 PM EST THIS EVENING FOR NYZ023>025-044-
045-055-056-062.
HIGH WIND WARNING UNTIL 7 PM EST THIS EVENING FOR NYZ009-
015>018-022-036-037-046-057.
LAKE EFFECT SNOW WARNING UNTIL 7 AM EST FRIDAY FOR NYZ009.
&&
$$
SYNOPSIS...
NEAR TERM...MLJ
SHORT TERM...
LONG TERM...MDP/TAC
AVIATION...PVN
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1150 AM EST THU JAN 31 2013
.SYNOPSIS...
COLDER AIR WORKING INTO THE AREA BEHIND A STRONG COLD FRONT WILL
PRODUCE STRONG GUSTY WINDS TODAY...IN ADDITION TO LAKE EFFECT
SNOWS DOWNWIND OF LAKES ERIE AND ONTARIO. BELOW NORMAL
TEMPERATURES AND SCATTERED SHOW SHOWERS WILL CONTINUE INTO THE
WEEKEND...DUE TO A COMBINATION OF LAKE EFFECT SNOW SHOWERS AND
WEAK UPPER LEVEL DISTURBANCES.
&&
.NEAR TERM /THROUGH TONIGHT/...
12 NOON UPDATE... WE`VE PUSHED BACK THE START TIME OF THE LES WRNG
BY A FEW HRS IN NRN ONEIDA (NOW 21Z). BASED ON THE LATEST KBUF VWP
(STILL A 260 FLOW OVER A DEEP LYR)...AND OVERALL RADAR
PRESENTATION...WE THINK THE ONSET OF THE +SN IN NRN ONEIDA WILL BE
SOMEWHAT DELAYED FROM OUR EARLIER FCST. THE AMTS STILL LOOK
REPRESENTATIVE...AS PARAMETERS SEEM FAVORABLE FOR FAIRLY INTENSE
RATES...ONCE THE SNOW DOES FINALLY MOVE IN.
10 AM UPDATE... OUR CURRENT FCST IS IN EXCELLENT SHAPE ATTM...SO
ONLY COSMETIC CHGS WERE MADE.
AS STG CAA CONTS TO FILTER ACRS THE FA LATE THIS MRNG...LES BANDS
ARE TRYING TO ORGANIZE OFF BOTH LKS ERIE AND ONT. AS JUDGED FROM
THE 12Z RAOBS AT BUF/DTX...THE MIXED LYR EXTENDS UP TO ABT 750
MB...WITH A FAIR MOISTURE SUPPLY UNDERNEATH THE BASE OF THE
INVERSION. GIVEN CONTD CYCLONIC FLOW...FURTHER COOLING WITH
TIME...AND IF ANYTHING...A DEEPENING OF THE SYNOPTIC MOISTURE THIS
AFTN AND EVE...THERE`S NO REASON NOT TO EXPECT THE DVLPMT OF
FAIRLY STG LAKE-EFFECT PLUMES OFF BOTH LKS.
IN-HOUSE CAPE/SHEAR NOMOGRAM SHOWS ENUF OVER-LAND INSTAB THROUGH
THIS EVE (00-03Z)...SO THAT THE BANDS MAY TAKE ON SOMEWHAT OF A CELLULAR
APPEARANCE...AT TIMES. HOWEVER...ORGANIZATION IS NOT LIKELY TO BE
SERIOUSLY COMPROMISED. ALSO...THE CSTAR-DERIVED INLAND EXTENT
APPLICATION DEPICTS A FAIRLY DEEP INLAND PENETRATION THROUGHOUT
THE EVE HRS...AT LEAST...WITH A GOOD UPSTREAM CONNECTION TO
HURON/NRN LK MI/SUPERIOR...AND ALSO STG 0-1 KM SPEED SHEAR. THIS
ALSO SEEMS WELL SUPPORTED BY SIM REFLECTIVITY PRESENTATIONS FROM
THE NAM12...LOCAL ARW...AND HRRR MODELS.
BOTTOM LN...THINGS APPEAR WELL ON TRACK FOR THE LES WRNG IN NRN
ONEIDA...WITH A PD OF VERY HVY SNOW ANTICIPATED...FROM ROUGHLY
22-06Z. GIVEN DEEP MOISTURE...AND EXCELLENT CRYSTAL GROWTH
PARAMETERS...2-3"/HR RATES ARE NOT OUT OF THE QUESTION. ELSEWHERE
(ONONDAGA/MADISON/SRN ONEIDA)...DESPITE SOME ANTICIPATED
WEAKENING LTR TNT...AS THE BAND DROPS SWD...THERE MAY BE ENUF
RESIDUAL INTENSITY FOR ADVSY-LVL ACCUMS. WE`LL RE-VISIT THIS SITN
EARLY THIS AFTN.
ACRS THE TWIN TIERS...SOME CONVECTIVE SHSN ARE LIKELY TO FORM BY
MID TO LATE AFTN...AIDED A BIT BY ADVECTION OF MOISTURE FROM LKS
ERIE AND SRN MI IN STG WRLY FLOW. OVERALL...THOUGH...THE NATURE OF
THEM WILL REMAIN SCTD.
AS FOR THE WINDS...THEY`RE LIKELY TO BE AT THEIR PEAK THROUGH ABT
18Z...WITH A SLOW DIMINISHING TREND THEREAFTER...AS JUDGED FROM
ISALLOBARIC AND MOMENTUM TRANSFER PROGS.
A STEADY OR SLOWLY FALLING TEMP TREND IS WELL HANDLED IN THE
GRIDS...SO ONLY VERY MINOR TWEAKS WERE NEEDED.
PREV DISC... 620 AM...WILL DROP THE FLOOD WATCH FOR ERN ZONES AS
STEADY RAIN IS MOVG OUT. OTRW JUST MINOR NEAR TERM TWEEKS WITH NO
SIG CHGS TO FCST. PREV BLO...
450 AM...DROPPED FLOOD WATCH FOR THE CNTRL SRN TIER AND PORTIONS
OF THE FINGER LAKES AS BACK EDGE OF STEADIER RAIN HAS EXITED THIS
RGN. MAY STILL SEE SOME MINOR FLOODING DUE TO RUNOFF BUT FLS`S
HANDLING THAT. CONVECTIVE FNTL LINE PRODUCED WIND GUSTS IN THE
40-50 MPH RECENTLY AT SYR/BGM. SYNOPTIC SCALE WINDS WILL BE
INCRSNG RAPIDLY LATER THIS MRNG ALL AREAS. PREV BLO...
BACK EDGE OF AREA OF STEADY RAIN AREA MOVING INTO WRN ZONES AS OF
315 AM...CLOSE TO THE PSN OF THE SFC CDFNT...AND WILL CONTINUE IT`S EWD
PROGRESS THROUGH THE EARLY MRNG HRS. SOME OF THE RAIN MAY MIX
BRIEFLY WITH SNOW BEFORE TAPERING OFF THIS MRNG. FLOOD WATCH
REMAINS ON EFFECT...WE HAVE ISSUED SOME FLS`S THUS FAR AND WILL
CONTINUE TO MONITOR CAREFULLY.
MAIN ISSUE TDA WILL BE THE STRONG WINDS DVLPNG THIS MRNG AND
CONTINUING INTO THE AFTN HRS. BASED ON OUR SUSTAINED AND PEAK WIND
GRIDS...WE ADDED STEUBEN...YATES AND SENECA COUNTIES INTO THE
WARNING.
SCATTERED SNOW SHOWERS ARE XPCTD TDA...MAINLY DUE TO LAKE
INFLUENCES. WE COULD SEE -SHSN OFF LAKE ERIE ACRS PORTIONS OF THE
TWIN TIERS THIS AFTN/EVNG. POTNL FOR 2-4 INCHES ACRS PORTIONS OF
WRN STEUBEN TNGT. AFTN SHIFT CAN RE-ASSESS AND DETERMINE IF A LOW
END ADVISORY IS NEEDED HERE.
AS FOR THE NRN ONEIDA LES EVENT...THIS EVENT APPEARS TO BE SIMILAR
TO LAST WEEKS. THE ARW PERFORMED WELL IN THAT CASE...AND THIS
MRNG`S RUC ALSO SHOWS GOOD AGREEMENT EARLY ON IN THE PD. IT
APPEARS THAT THE BAND WILL NOT MAKE A MOVE INTO NRN ONEIDA UNTIL
LATE THIS AFTN...PERSISTING OVER THAT AREA TIL ARND 06Z BEFORE
DROPPING SWD AS FLOW BCMS MORE WNWLY. AS THIS OCCURS...MESO MDLS
SHOW THE BAND OVER LAKE ONTARIO DROPPING TO A PSN NEAR/ALONG THE
SRN SHORE OF LAKE ONTARIO LATE TNGT/TWDS DAYBREAK. THIS IS WHAT
OCCURRED WITH THE LAST BAND...AND RESULTED IN RAPID WEAKENING OF
THE BAND OVER THE BGM CWA DUE (AT LEAST IN PART) TO THE LOSS OF
OVER-LAKE TRAJECTORY. THIS IS ALSO HINTED AT IN THE MESO MDLS FRI
MRNG. FOR NOW WE HAVE THE BAND DROPPING SWD INTO ONON/MAD IN THE
09-12Z TIME FRAME...WITH POTNL FOR LOW END ADVISORY ACCUMS MAINLY
OVER NW ONON. GIVEN THE NUMEROUS HEADLINES ALREADY IN EFFECT AND
THE FACT WE HAVE SOME TIME TO TAKE A CLOSER LOOK AT THIS...WE WILL
JUST MENTION THE POTNL IN THE HWO AND LET THE DAY SHIFT ISSUE
HEADLINES FOR THIS EVENT IF NEEDED.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
A COUPLE OF CLIPPER-TYPE SYSTEMS WILL AFFECT THIS WEEKEND...WITH
SCATTERED SNOW SHOWERS. A MORE WDSPRD AREA OF LGT SNOW COULD DVLP
IN THE WARM ADVECTION PTRN AHEAD OF THE CLIPPER APRCHNG SAT NGT.
IN GNRL...CHC POPS FOR -SHSN AND BLO NORMAL TEMPS.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
GRIDS WERE ADJUSTED SOME TO ACCOUNT FOR LATEST HPC GUIDANCE AND
GFS/ECMWF MODELS. NO BIG CHANGE TO GOING FORECAST OVERALL...BUT I
DID UPGRADE POPS INTO LIKELY CATEGORY FOR CENTRAL NY AND AT LEAST
HIGHER CHANCE FOR NORTHEAST PA SUNDAY WITH FAIR AGREEMENT ON BEING
INVOLVED IN MERGER BETWEEN DEVELOPING COASTAL LOW AND INCOMING
NORTHERN STREAM SYSTEM/CLIPPER. COULD EASILY RESULT IN LIGHT
COATING OF SNOW. ANOTHER WEAK CLIPPER CONTINUES TO LOOK POSSIBLE
MONDAY NIGHT/TUESDAY.
PREVIOUS DISCUSSION...
FOLLOWED HPC GUIDANCE. MODELS ARE SIMILAR WITH NO LARGE STORMS.
REMAIN UNDER A NORTHEAST US UPPER LEVEL TROF. SEASONABLE WEATHER
WITH WEAK LOW PRESSURE SYSTEMS FOLLOWED BY LAKE EFFECT. ALL PRECIP
WILL BE SNOW WITH HIGHS AROUND 30 AND LOWS IN THE TEENS. THE WEAK
SYSTEMS GO THROUGH SUNDAY AND MONDAY NIGHT...WITH LAKE EFFECT ON
THE OTHER DAYS. COULD BE A 12 HOUR DRY BREAK BETWEEN SYSTEMS WITH
WEAK HIGH PRESSURE MON AFTN.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
12Z UPDATE...
STRONG COLD FRONT IS JUST FINISHING ITS BLAST THROUGH THE
AREA...TAKING THE STEADIER RAIN SHOWERS WITH IT. WINDS WILL HAVE A
MUCH EASIER TIME MIXING DOWN IN THE COLD AIR BEHIND THE
FRONT...ALLOWING WESTERLY GUSTS FREQUENTLY IN THE 30-40 KT RANGE.
GUSTS AT KSYR AND PERHAPS KRME WILL EVEN TOP OUT AROUND 35-45 KTS
AT TIMES TODAY. EXPECTING SCT-BKN CLOUD DECK WITH SCT -SHSN AND
MVFR CIG FOR SOME TERMINALS. THOUGH GENERALLY VFR TO MVFR IN TAFS
TODAY WITH THE SNOW FLURRIES...SOME TERMINALS WILL HAVE TO WATCH
FOR BRIEF SURPRISE IFR VIS FROM A HEAVIER LAKE EFFECT SNOW SHOWER.
THE MAIN LAKE ONTARIO SNOW BAND WILL AT FIRST DEVELOP NORTH OF THE
AREA THIS AFTERNOON...BUT SHOULD EDGE SOUTH ENOUGH TO INVOLVE KRME
IN OCCASIONAL IFR VIS AFTER 03Z...AND BY 09Z ONWARD FOR KSYR.
.OUTLOOK...
FRI THRU SAT NGT...MVFR-IFR FROM LAKE -SHSN IN CENTRAL NY.
SUN...A COLD FRONT WITH POSSIBLE MVFR AND IFR SNOW
SUN NGT-MON...MORE MVFR/IFR LAKE -SHSN MAINLY CENTRAL NY.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...WIND ADVISORY UNTIL 7 PM EST THIS EVENING FOR PAZ038>040-043-
044-047-048-072.
NY...WIND ADVISORY UNTIL 7 PM EST THIS EVENING FOR NYZ023>025-044-
045-055-056-062.
HIGH WIND WARNING UNTIL 7 PM EST THIS EVENING FOR NYZ009-
015>018-022-036-037-046-057.
LAKE EFFECT SNOW WARNING FROM 4 PM THIS AFTERNOON TO 7 AM EST
FRIDAY FOR NYZ009.
&&
$$
SYNOPSIS...
NEAR TERM...MLJ
SHORT TERM...
LONG TERM...MDP/TAC
AVIATION...MDP
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1208 PM EST THU JAN 31 2013
.SYNOPSIS...
COOL HIGH PRESSURE WILL BUILD IN FROM THE WEST TODAY...WITH BELOW
NORMAL TEMPERATURES EXPECTED. IT WILL BE BREEZY TODAY... ALTHOUGH
WINDS WILL NOT BE AS STRONG AS LAST NIGHT. A SERIES OF DRY COLD
FRONTS WILL MOVE ACROSS THE AREA. THE FIRST FRONT WILL CROSS THE
AREA FRIDAY FOLLOWED BY ANOTHER ON SUNDAY AND YET ANOTHER ON TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1230 AM THURSDAY...NO SIGNIFICANT CHANGES HAVE BEEN MADE TO
THE FORECAST. TEMPERATURES ARE SLOW TO RISE AS EXPECTED BUT ARE
FOLLOWING THE HOURLY CURVE DERIVED FROM A NAM/RUC BLEND WITHIN +/-1
DEGREE. NO CHANGES ARE NEEDED. PREVIOUS DISCUSSION FROM 930 AM
FOLLOWS...
THE SEASONS HAVE CHANGED YET AGAIN WITH YESTERDAY`S SPRING-LIKE
WEATHER REPLACED BY A RETURN TO WINTER TODAY. COLD ADVECTION ON
WESTERLY WINDS BEHIND LAST NIGHT`S STRONG COLD FRONT WILL ALMOST
PERFECTLY BALANCE NEARLY FULL SUNSHINE TODAY AND TEMPERATURES WILL
STRUGGLE JUST TO RISE A FEW DEGREES BY AFTERNOON...REACHING 53-56
DEGREES AREAWIDE. THE 12Z GSO SOUNDING WAS BEST SIMULATED BY THE 12Z
NAM AND RUC MODELS...AND THESE ARE THE TWO MODELS I BLENDED FOR MY
UPDATED FORECAST TODAY. DOWNWARD REVISIONS HAVE BEEN MADE TO
DEWPOINT FORECASTS FOR THE AFTERNOON HOURS WITH LOWER 20S DEWPOINTS
EXPECTED TO MIX DOWN FROM A RESERVOIR OF VERY DRY AIR ALOFT.
PRECIPITABLE WATER VALUES TODAY SHOULD RANGE FROM 0.20 TO 0.25
INCHES.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 3 AM THURSDAY...SHORTWAVE ROUNDING BASE OF MID LEVEL TROUGH
EARLY FRI HELPS DRIVE A REINFORCING SHOT OF COLD AIR INTO THE
REGION. DRY COLD FRONT PUSHES OFFSHORE BY MIDDAY WITH A PERIOD OF
BRIEF BUT STRONG COLD ADVECTION ENDING LATE FRI NIGHT. TEMP DROP
WILL BE SIGNIFICANT WITH GUIDANCE SHOWING 850 TEMPS DECREASING BY
AS MUCH AS 10C IN SOME PLACES IN UNDER 12 HOURS. DEEP WEST TO
NORTHWEST FLOW FRI INTO FRI NIGHT HELPS KEEP SKIES CLEAR. PATTERN
BECOMES LESS AMPLIFIED AND MORE PROGRESSIVE LATE FRI
NIGHT...SHUTTING OFF COLD ADVECTION. MORE PROGRESSIVE EVOLUTION OF
MID LEVEL PATTERN HELPS MOVE CENTER OF SURFACE RIDGE AXIS OVER THE
REGION FOR SAT MORNING...ALLOWING FOR SOME RADIATIONAL COOLING. DO
NOT ANTICIPATE EFFECT TO BE VERY STRONG BUT TYPICAL COLD SPOTS
WILL FLIRT WITH TEENS FOR LOWS. HIGHS FRI WILL STRUGGLE TO REACH
CLIMO WHILE LOWS WILL DROP INTO THE LOW TO MID 20S IN MOST AREAS
SAT MORNING.
SURFACE RIDGE AXIS SHIFTS OFFSHORE SAT WITH WEAK RETURN FLOW SETTING
UP FOR THE END OF THE PERIOD. ALOFT ANOTHER SHORTWAVE HELPS AMPLIFY
THE MID LEVEL PATTERN...RESULTING IN A SHORT PERIOD OF DEEP
WEST-SOUTHWEST FLOW AHEAD OF ANOTHER COLD FRONT MOVING INTO THE
REGION AS THE PERIOD ENDS. ANTICIPATE AN INCREASE IN MID AND
UPPER LEVEL CLOUD ASSOCIATED WITH THIS WAVE BUT DURATION OF RETURN
FLOW IS NOT ENOUGH TO BRING SIGNIFICANT MOISTURE BACK INTO THE
REGION BEFORE THE FRONT PASSES. ALTHOUGH SOME GUIDANCE IS POINTING
TO SOME LIGHT ISOLATED PRECIP EARLY SUN MORNING DO NOT THINK THIS
WILL BE THE CASE. WILL MAINTAIN A POP FORECAST AROUND 10 SAT
NIGHT. TEMPERATURES REMAIN BELOW CLIMO SAT BUT END UP MUCH CLOSER
TO CLIMO SAT NIGHT.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 3 AM THURSDAY...A RATHER REPETITIVE PATTERN FOR THE EXTENDED AS
AREAS OF HIGH PRESSURE PUSH OFFSHORE AHEAD OF A SERIES OF WEAK
COLD FRONTS.
FIRST COLD FRONT WILL CROSS THE AREA VERY EARLY SUNDAY MORNING.
LIMITED FORCING COMBINED WITH ONLY MARGINAL PWATS SUGGESTS FROPA
WILL BE DRY...AND ONLY ACT TO REINFORCE THE COOL AIR.
HOWEVER...ANY WEAK CAA REMAINS WELL DISPLACED BEHIND THE
FRONT...SO SUNDAY WILL END UP BEING WARMER THAN
SATURDAY...ALTHOUGH BOTH DAYS WILL BE AROUND TO SLIGHTLY BELOW
CLIMO.
ANOTHER LARGE BUT WEAK AREA OF HIGH PRESSURE BUILDS DOWN FROM THE NW
LATE SUNDAY AND PERSISTS INTO TUESDAY WHILE SLOWLY DRIFTING ACROSS
THE REGION. THIS CONTINUES THE COOL AND DRY WEATHER WITH NEAR TO
SLIGHTLY-BELOW SEASONABLE TEMPS. THIS HIGH PRESSURE THEN DRIFTS
OFFSHORE TUESDAY AHEAD OF ANOTHER COLD FRONT PROGGED TO CROSS THE
AREA LATE IN THE DAY. GUIDANCE SHOWING CONSIDERABLE AMPLITUDE
DIFFERENCES IN THE TROUGH DRIVING THIS FRONT WHICH WILL HAVE
SIGNIFICANT IMPACT ON PRECIP POTENTIAL. FOR NOW WILL KEEP INHERITED
SCHC/SILENT POP FOR D6 SINCE BENEFICIAL CHANGES CANNOT BE MADE AT
THIS TIME. TUESDAY WILL LIKELY BE THE WARMEST DAY OF THE PERIOD
THOUGH AHEAD OF THE COLD FRONT...WITH TEMPS RETURNING TO BELOW CLIMO
FOR WEDNESDAY AS ANOTHER AREA OF HIGH PRESSURE RIDGES DOWN FROM THE
NW.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
AS OF 18Z...VFR WITH CLEAR SKIES THIS AFTERNOON. A TIGHT PRESSURE
GRADIENT WILL PRODUCE WSW-W WINDS 15-25 KNOTS WITH SPEEDS GRADUALLY
DIMINISHING. VFR THIS EVENING AND OVERNIGHT WITH WSW WINDS 6-12
KNOTS. ANOTHER COLD FRONT WILL TRAVERSE THE TERMINALS AFTER SUNRISE.
MAINLY SCATTERED VFR LEVEL LOW CLOUDS EXPECTED AS WINDS SHIFT TO THE
WNW GUSTING TO AROUND 25 KNOTS.
EXTENDED OUTLOOK...VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1230 PM THURSDAY...NO SIGNIFICANT CHANGES HAVE BEEN MADE TO
THE FORECAST. WINDS OUT AT FRYING PAN SHOALS BUOY ARE GUSTING TO 33
KNOTS ON THE LATEST OBSERVATION...AND GUSTS AT THE VARIOUS PIERS AND
BEACH OBSERVATIONS FINALLY ARE BELOW 30 KNOTS. SEAS CONTINUE TO
DIMINISH AS WELL. THE SMALL CRAFT ADVISORY WILL REMAIN POSTED FOR
THE ONGOING WINDS...AND FOR THE ANTICIPATION OF A RENEWED SURGE OF
NORTHWEST WINDS FRIDAY MORNING BEHIND A SECOND COLD FRONT. PREVIOUS
DISCUSSION FROM 930 AM FOLLOWS...
EARLIER BLOWOUT TIDE CONDITIONS HAVE ABATED. WATER LEVELS AS
MEASURED AT THE OFFICIAL NOS (NATIONAL OCEAN SERVICE) TIDE GAUGES
REACHED -1.92 FT MLLW AT WRIGHTSVILLE BEACH... AND -1.50 FT MLLW AT
MYRTLE BEACH. FOR THE NEXT LOW TIDE JUST AFTER 4 PM...WESTERLY WINDS
SHOULD BE DIMINISHING WITH LESS IMPACT ON COASTAL WATER LEVELS.
OTHERWISE...WEST WINDS AROUND 30 KNOTS WITH FREQUENT GALE-FORCE
GUSTS ARE STILL OCCURRING ACROSS THE AREA THIS MORNING. I WISH THE
GALE WARNING WERE STILL UP AS GUSTS AT THE FRYING PAN SHOALS BUOY
CONTINUE TO ECLIPSE 40 KNOTS...AND WITH 12 FOOT SEAS I AM FAIRLY
CERTAIN SUSTAINED GALE-FORCE WINDS ARE OCCURRING BEYOND 15 MILES
FROM SHORE. THESE VERY STRONG WINDS SHOULD BEGIN TO ABATE OVER THE
NEXT 2 HOURS AS HIGH PRESSURE OVER SOUTHERN LOUISIANA NOSES TOWARD
THE CAROLINAS AND OUR PRESSURE GRADIENT BEGINS TO WEAKEN.
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 3 AM THURSDAY...SMALL CRAFT ADVISORY CONTINUES INTO FRI BEFORE
PASSAGE OF COLD FRONT AND DEVELOPMENT OF OFFSHORE FLOW PUSHES 6
FT SEAS BEYOND 20 NM. STRONG BUT BRIEF COLD ADVECTION DURING THE
SECOND HALF OF FRI INTO FRI NIGHT MAY REQUIRE A PERIOD OF SCEC
HEADLINES. HIGH PRESSURE BUILDS IN FROM THE WEST LATE FRI NIGHT
THEN SHIFTS OVER THE WATERS DURING SAT. WEAKENING GRADIENT ALLOWS
WIND SPEEDS TO DROP FROM A SOLID 20 KT FRI TO UNDER 10 KT BY SAT
MORNING. RETURN FLOW STARTS TO DEVELOPING SAT AFTERNOON AS HIGH
PRESSURE SLIDES EAST OF THE WATERS. GRADIENT BECOMES PINCHED AHEAD
OF NEXT COLD FRONT...WITH SOUTHWEST WINDS INCREASING TO 15 KT AS
THE PERIOD ENDS. SEAS SUBSIDE DURING FRI...DROPPING FROM 4 TO 7 FT
AT THE START OF THE PERIOD TO 3 TO 4 FT FRI EVENING. SEAS FALL
FURTHER...CLOSE TO 2 FT...EARLY SAT BEFORE STARTING TO BUILD BACK
CLOSER TO 3 TO 4 FT LATE IN THE PERIOD AS SOUTHWEST WINDS
INCREASE.
LONG TERM /SUNDAY THROUGH MONDAY/...
AS OF 3 AM THURSDAY...A COLD FRONT WILL CROSS THE WATERS SUNDAY...
TURNING WINDS TO THE W/NW AT 10-15 KTS ON SUNDAY BEFORE SLOWLY
EASING TO LIGHT AND VARIABLE AGAIN MONDAY AS HIGH PRESSURE BUILDS
BACK OVER THE WATERS. SEAS WILL BE PRIMARILY WIND-DRIVEN THROUGH
THE PERIOD...INCREASING FOR A SHORT TIME SUNDAY UP TO 2-4 FT...
THEN DECREASING TO 1 TO 2 FT MONDAY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 1 PM EST FRIDAY FOR
AMZ250-252-254-256.
&&
$$
NEAR TERM...TRA
SHORT TERM...III
LONG TERM...JDW
AVIATION...MRR
AREA FORECAST DISCUSSION
NWS PORTLAND OR
843 AM PST THU JAN 31 2013
.SYNOPSIS...ONE LAST SYSTEM MOVING OVER THE TOP OF AN OFFSHORE HIGH
PRESSURE WILL BRING SOME LIGHT RAIN TO THE NORTHERN TIER TODAY.
STRENGTHENING HIGH PRESSURE WILL BRING DRY WEATHER FOR AT LEAST
FRIDAY AND SATURDAY...THOUGH THERE WILL BE PLENTY OF LOW CLOUDS AND
FOG ACROSS THE INTERIOR VALLEYS. EAST WINDS WILL INCREASE ACROSS
THE WESTERN COLUMBIA RIVER GORGE LATE FRIDAY LIKELY CAUSING THE
PORTLAND METRO AREA TO CLEAR THOUGH. SYSTEMS LATE THIS WEEKEND AND EARLY
NEXT WEEK APPEAR WEAK...WITH BETTER CHANCES OF PRECIPITATION AROUND
THE MIDDLE OF NEXT WEEK.
&&
.SHORT TERM...DOPPLER RADAR MOSAIC SHOWS A BAND OF LIGHT RAIN MOVING
INTO SOUTHWEST WASHINGTON AND EXTREME NORTHWESTERN OREGON. THIS RAIN
IS ASSOCIATED WITH AN AREA OF ISENTROPIC LIFT ACCOMPANYING A WEAK
FRONT PUSHING SOUTHEASTWARD. AS THIS FRONT DETACHES FROM ITS PARENT
UPPER LEVEL TROUGH OVER BRITISH COLUMBIA...EXPECT IT TO STALL AND
WEAKEN IN THE VICINITY OF THE COLUMBIA RIVER THIS AFTERNOON AND
TONIGHT...AS IT BECOMES ORIENTED MORE LATITUDINALLY.
THE CURRENT PRECIPITATION BAND IS A LITTLE MORE EXTENSIVE AND
ARRIVING EARLIER THAN MOST MODELS WOULD SEEM TO SUGGEST...EVEN THE
SHORT TERM MODELS. THE LATEST HRRR SUGGESTS A SHOWER OR TWO WILL BE
POSSIBLE ACROSS THE PORTLAND METRO AREA LATER THIS AFTERNOON AND
GIVEN THE SOUTHWARD EXTENT OF PRECIPITATION ON RADAR...THIS IDEA
SEEMS PLAUSIBLE. AS A RESULT OF THE ABOVE...POPS WERE INCREASED FOR
TODAY...AND GRIDS WERE SPLIT INTO THREE HOURS TO ATTEMPT TO REFLECT
THE LATEST TIMING AND TRENDS IN RAIN CHANCES.
THE OTHER PROBLEM CHILD THIS MORNING ARE AREAS OF FOG ACROSS THE
PORTLAND METRO AREA. GIVEN PORTIONS OF THE METRO AREA...SUCH AS
DOWNTOWN...REMAIN FOG FREE...WILL CONTINUE TO HANDLE THE FOG PROBLEM
WITH NOWCASTS. GIVEN THE LOW SUN ANGLE AND LIGHT LOW LEVEL FLOW...I
DID EXPAND THE FOG MENTION IN THE GRIDS UNTIL 1 PM AS IT WILL LIKELY
BE SLOW TO LIFT AND MIX OUT.
SKY COVER GRIDS WERE TWEAKED AS WELL FURTHER SOUTH AS AREA CAMS AND THE
FIRST VISIBLE SATELLITE IMAGES OF THE DAY INDICATE MOSTLY SUNNY TO
PARTLY CLOUDY SKIES EXIST ACROSS THE CENTRAL OREGON COAST AND THE
CENTRAL OREGON CASCADES. /NEUMAN
.LONG TERM...SATURDAY NIGHT THROUGH TUESDAY...THE UPPER LEVEL RIDGE
IN PLACE TO START THE WEEKEND BEGINS TO BREAK DOWN SLOWLY TOWARD LATE
SATURDAY AS A WEAK BOUNDARY APPROACHES THE AREA. THIS BOUNDARY WILL
AT THE LEAST BRING INCREASING CLOUDS TO THE AREA BY SUNDAY...BUT IT
WILL BE SHEARING AND SPLITTING...SO EXPECT RAIN CHANCES TO BE ON THE
LOW END. A QUICK MOVING BUT STRONGER FRONTAL SYSTEM WILL THEN
APPROACH THE COAST LATE SUNDAY INTO MONDAY. THIS SYSTEM SEEMS TO
FURTHER BREAK DOWN THE RIDGE...BUT MODELS DISAGREE ON HOW MUCH
MOISTURE IT PUSHES INLAND...BEFORE THE RIDGE REBOUNDS ON MONDAY
AFTERNOON. ANOTHER FRONTAL SYSTEM IS SHOWN TO SWING THROUGH THE AREA
LATER IN THE DAY TUESDAY OR TUESDAY EVENING. A COLD UPPER TROUGH
WILL THEN MOVE THROUGH FOR THE LATTER HALF OF THE WEEK. KMD/BROWN &&
.AVIATION...FLIGHT CONDITIONS REMAIN VARIABLE THIS MORNING...
RANGING ANYWHERE FROM LIFR TO VFR CATEGORY. MOIST LOW LEVELS IN A
LIGHT ONSHORE FLOW ARE LIKELY TO KEEP A VARIETY OF CONDITIONS
ACROSS THE AREA. OVERALL TREND IN THE AFTERNOON IS LIKELY TO BE
FOR SLOW IMPROVEMENT TO PREDOMINANTLY MVFR IN THE NORTH AND AND
VFR CATEGORY IN THE SOUTH. EXPECT A RETURN TO IFR CONDITIONS
ACROSS MUCH OF THE INTERIOR TONIGHT WITH A MIX OF MVFR AND IFR
CONDITIONS ALONG THE COAST.
KPDX AND APPROACHES...IFR AND LIFR CONDITIONS WILL CONTINUE THIS
MORNING. CONDITIONS WILL LIKELY IMPROVE TO MVFR AFTER 20Z TODAY.
IFR CONDITIONS ARE LIKELY TO RE-DEVELOP AFTER 08Z TONIGHT AS THE
AIRMASS STABILIZES.
&&
.MARINE...FAIRLY QUIET NEXT COUPLE OF DAYS AS A HIGH PRES SYSTEM IS
LIKELY TO KEEP WINDS BELOW SMALL CRAFT CRITERIA THROUGH THE WEEKEND.
A LONG PERIOD SWELL OUT OF THE W IS EXPECTED TO BEGIN SHOWING UP
FRI...AND ULTIMATELY RAISE SEAS ABOVE 10 FT ON SAT AND SUN. ALTHOUGH
THE OFFSHORE WAVE HEIGHTS ARE EXPECTED TO PEAK IN THE 10 TO 12 FT
RANGE SAT AND SUN...THE LONG PERIODS MAY PUSH BREAKERS AS HIGH AS
THE 18 TO 20 FT RANGE.
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL 10 AM
PST THIS MORNING.
SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR FROM 5 PM THIS
AFTERNOON TO 9 PM PST THIS EVENING.
&&
$$
MORE WEATHER INFORMATION ONLINE AT...HTTP://WEATHER.GOV/PORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON
FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS
COMMONLY REFERRED TO AS THE FORECAST AREA.