Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 11/25/13
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
959 AM MST SAT NOV 23 2013
.SYNOPSIS...
PACIFIC LOW PRESSURE WILL CONTINUE TO PRODUCE SCATTERED TO NUMEROUS
SHOWERS TODAY FROM PHOENIX EASTWARD...WITH LESSER COVERAGE OVER THE
WESTERN DESERTS. THERE WILL BE A LINGERING CHANCE FOR RAIN
SUNDAY...MAINLY OVER SOUTH-CENTRAL ARIZONA BUT ACCUMULATIONS...IF
ANY...WILL BE MUCH LOWER. HIGH TEMPERATURES WILL REMAIN WELL BELOW
NORMAL THIS WEEKEND. DRY WEATHER AND WARMER TEMPERATURES WILL RETURN
MONDAY THROUGH THE LATTER PART OF NEXT WEEK.
&&
.DISCUSSION...
THE UPPER LOW CENTER HAS STARTED TO MAKE SOME MOVEMENT TO THE
NORTHEAST OVER THE PAST SIX HOURS. THE MAIN BAND OF RAIN HAS ALSO
SHIFTED MORE TO THE EAST AND CURRENTLY RESIDES FROM ACROSS THE FAR
EAST METRO PHOENIX AREA EASTWARD THROUGH GILA COUNTY. RAINFALL RATES
ARE GENERALLY ON THE LIGHT SIDE...OR LESS THAN A TENTH OF AN INCH
PER HOUR. CLOSER TO THE LOW CENTER AND MID LEVEL COOL CORE...HEAVIER
AND MORE SHOWERY TYPE RAIN HAS AFFECTED NORTHWEST MARICOPA COUNTY
SINCE 7 AM. LATEST HRRR MODEL REFLECTIVITY SHOWS THE EASTERN RAIN
BAND EVENTUALLY PUSHING EASTWARD AND WEAKENING THIS AFTERNOON. MORE
SCATTERED SHOWERY TYPE RAIN WILL BE POSSIBLE THROUGHOUT THE DAY
MAINLY FOCUSED ACROSS SOUTHWEST ARIZONA. HAVE TRIMMED BACK ON POPS
FOR THIS AFTERNOON ACROSS THE REST OF THE METRO PHOENIX AREA WHERE
RAIN HAS STOPPED. HOWEVER...UNTIL THE LOW MOVES OUT OF THE AREA
SUNDAY NIGHT...SLIGHT CHANCE TO CHANCE POPS ARE IN THE FORECAST FOR
MUCH OF THE AREA. WILL SEE VERY LITTLE DAYTIME IMPROVEMENT IN
TEMPERATURES...MAYBE INCREASING 5-7 DEGREES IN MOST AREAS FROM
OVERNIGHT LOWS.
&&
.PREVIOUS DISCUSSION...
IMPRESSIVE PACIFIC CLOSED UPPER LOW CONTINUED TO SPIN MORE OR LESS
IN PLACE ALONG THE FAR SERN CA/FAR NRN BAJA COAST AT 3 AM THIS
MORNING...KEEPING A PRONOUNCED DIFLUENT SIGNATURE IN PLACE OVER
ARIZONA. BANDS OF RAIN SHOWERS CONTINUED TO MOVE NORTH ACROSS SOUTH
CENTRAL ARIZONA...HOWEVER THE INTENSITIES WERE LESS THAN WHAT WAS
OBSERVED EARLIER...DURING THE DAY ON FRIDAY. MOST HOURLY RAINFALL
TOTALS HAVE BEEN BELOW ONE TENTH OF AN INCH SINCE MIDNIGHT...AND
LATEST 3 HOURS ACCUMULATIONS FROM THE MARICOPA COUNTY FLOOD CONTROL
GAGES SHOWED VALUES BELOW ONE TENTH OF AN INCH ACROSS WESTERN
MARICOPA COUNTY...AND BETWEEN ONE QUARTER AND ONE HALF INCH OVER THE
GREATER PHOENIX AREA. LITTLE RAINFALL WAS OCCURRING OVER SERN CA AND
THE WESTERN DESERTS...AND IR/VAPOR IMAGERY DEPICTED DRY SLOTTING
OCCURRING OVER OUR WESTERN CWA. PROGS ALL INDICATE THAT THE UPPER
LOW WILL START TO MOVE INLAND TODAY...SHIFTING THE DEEPER MOISTURE
EASTWARD ALONG WITH THE BEST DYNAMICS AND UPPER DIFLUENCE. GIVEN
THAT THE RAINFALL INTENSITIES HAVE BEEN DIMINISHED FOR SOME TIME AND
THAT THERE WILL CONTINUE TO BE DECREASING SHOWERS FROM THE WEST
DURING THE DAY TODAY...WE OPTED TO CANCEL THE FLOOD WATCH EARLY. IT
IS POSSIBLE THAT SMALLER HYDRO ISSUES MAY CROP UP DURING THE
DAY...PROBABLY ACROSS THE EASTERN PORTIONS OF THE GREATER PHOENIX
AREA OR SOUTHERN GILA COUNTY...BUT THEY MOST LIKELY WOULD BE ABLE TO
BE HANDLED WITH FLOOD ADVISORIES. CURRENT POP TRENDS FOR TODAY AND
TONIGHT LOOK GOOD AND FEW CHANGES WERE MADE. EXPECT SLIGHT CHANCES
FOR SHOWERS ACROSS THE WESTERN CWA BY THIS EVENING WITH LINGERING
CHANCES FROM PHOENIX EASTWARD. AS THE LOW EDGES EASTWARD...SOME COLD
AIR ALOFT WILL SHIFT INTO THE WESTERN/CENTRAL DESERTS LEADING TO
SOME INSTABILITY AND A SLIGHT CHANCE FOR EMBEDDED THUNDERSTORMS.
THUS FORECASTS FROM PHOENIX WESTWARD MENTION SLIGHT CHANCES FOR
THUNDER THIS AFTERNOON. EXPECT HIGH TEMPS TODAY TO REMAIN AT LEAST
10 DEGREES BELOW NORMALS...GIVEN THE COOL DAMP AIRMASS IN PLACE AND
THE PERSISTENT CLOUDS AND SHOWERS.
UPPER LOW WILL CONTINUE TO BODILY MOVE EASTWARD ACROSS THE STATE
SUNDAY...LEADING TO A DRYING TREND FROM THE WEST...WITH PRECIP
CHANCES LOWERING TO SLIGHT CHANCES BY AFTERNOON FROM THE GREATER
PHOENIX AREA WESTWARD. MAY SEE AN ISOLATED AFTERNOON THUNDERSTORM
SUNDAY ACROSS THE CENTRAL DESERTS AS THE COLD POOL ALOFT SHIFTS
OVERHEAD. OF COURSE...WITH THE THE MAIN LOW MOVING DIRECTLY
OVERHEAD...TEMPS SUNDAY WILL STAY VERY COOL WITH MOST DESERT LOCALES
STRUGGLING TO REACH INTO THE LOW TO MID 60S.
HIGH PRESSURE WILL BUILD INTO THE AREA FROM THE WEST MONDAY INTO THE
MIDDLE OF NEXT WEEK FOR DRY CONDITIONS AND A WARMING TREND. EXPECT
HIGHS TO CLIMB GRADUALLY...REACHING SEASONAL NORMALS BY TUESDAY
UNDER MOSTLY SUNNY OR SUNNY SKIES.
VARIOUS EXTENDED RANGE MODELS...SUCH AS GFS...ECMWF AND
CANADIAN...AS WELL AS THEIR ENSEMBLES...ALL SUGGEST THAT ANOTHER
PACIFIC LOW PRESSURE SYSTEM MAY IMPACT THE DESERT SOUTHWEST LATER
NEXT WEEK. HOWEVER...ENSEMBLE MEMBER SPREADS ARE EXTREME AND THERE
IS LITTLE RUN TO RUN CONSISTENCY WITH THESE MODELS AND LITTLE MODEL
TO MODEL CONSISTENCY. LATEST GFS MOVES A SIGNIFICANT LOW INTO
ARIZONA BY NEXT FRIDAY...WHILE THE ECMWF CLOSES OFF THE LOW AND
SHIFTS IT WELL OFF THE CA COAST AT THAT TIME. GIVEN MODEL
UNCERTAINTIES...LEFT SOME MODEST POPS ACROSS THE CWA THURSDAY INTO
FRIDAY...MAINLY OVER THE WESTERN DESERTS. POPS ARE NEAR OR A BIT
ABOVE CLIMO. SHOULD THE LATEST EUROPEAN GUIDANCE BE SPOT ON...WE
WILL NOT SEE ANY PRECIP THRU AT LEAST FRIDAY...BUT IT HAS SHOWN
SIGNIFICANT DEVIATIONS RUN TO RUN SO ITS CURRENT SOLUTION CANNOT BE
TRUSTED.
&&
.AVIATION...
SOUTH-CENTRAL AZ...INCLUDING KPHX...KIWA...AND KSDL...
RAIN SHOWER ACTIVITY HAS GRADUALLY DIMINISHED IN AREAL COVERAGE
OVERNIGHT WHILE ALSO TRANSITIONING EAST OF THE PHX METRO. LIGHT
SHOWERS WILL CONTINUE TO STREAM FROM SOUTH TO NORTH GNLY THROUGH
23/1800Z WARRANTING -SHRA MENTION. EARLY MORNING CIGS HAVE THE
POTENTIAL TO BOUNCE BETWEEN VFR AND MVFR LEVELS. CONFIDENCE IS
MODERATE OF CIGS BREAKING OUT IN TO THE 5-6KFT RANGE BY MIDDAY.
SHOWERS WILL BECOME MORE VICINITY IN NATURE BY EVENING AS THEY
TRANSITION FURTHER TO THE EAST. EXPECT PERIODIC TERRAIN OBSCURATIONS
FROM CLOUDS POSSIBLE INTO THE OVERNIGHT HOURS. WINDS WILL GENERALLY
HOLD EAST HEADINGS WITH 8 TO 12 KNOTS OF SPEED POSSIBLE.
SOUTHEAST CALIFORNIA INCLUDING KIPL AND KBLH...
WIDELY SCATTERED LIGHT SHOWER ACTIVITY WILL PERSIST ACROSS SE
CALIFORNIA THROUGH THIS EVENING...PARTICULARLY AT KBLH WHERE MVFR
CIGS/VSBY IMPACTS ARE EXPECTED THROUGH MID MORNING. UPPER LOW
PRESSURE RESPONSIBLE FOR GENERATING THE PRECIP ACTIVITY WILL BEGIN
TO MOVE FURTHER INLAND OVER SOUTHEAST CALIFORNIA...INTRODUCING
COOLER TEMPERATURES ALOFT AND THE POTENTIAL FOR ISOLATED THUNDER
DEVELOPMENT DURING THE AFTERNOON HOURS. CONFIDENCE IS LOW TO
MODERATE FOR ORGANIZED ACTIVITY NEAR THE TERMINALS...SO LEFT ANY
VCTS OR CB MENTION OUT OF THE 12Z TAF PACKAGE.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
MONDAY THROUGH FRIDAY...
LOW PRESSURE WILL CONTINUE TO EXIT TO THE EAST MONDAY...LEAVING WELL
BELOW NORMAL TEMPERATURES AND A DRYING TREND IN TERMS OF
PRECIPITATION. COLDER AIR WILL LIE AGAINST THE CONTINENTAL DIVIDE
THROUGH MIDWEEK...KEEPING SURFACE GRADIENTS TIGHTENED AND MORE
PRONOUNCED EASTERLY WINDS DEVELOPING ACROSS EASTERN AND CENTRAL
ARIZONA. HIGH PRESSURE WILL BUILD ACROSS THE REGION...RESULTING IN A
WARMING TREND THROUGH MIDWEEK AND A RETURN TO NEAR NORMAL
TEMPERATURES BY TUESDAY. LATER INTO NEXT WEEK ANOTHER STORM SYSTEM
IS FORECAST TO DEVELOP OFF THE PACIFIC BRINGING WITH IT COOLER
TEMPERATURES FOR THE LATE WEEK AND POTENTIALLY ANOTHER ROUND OF
RAIN/SNOW SHOWER ACTIVITY TO THE REGION BY NEXT WEEKEND.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...KUHLMAN
PREVIOUS DISCUSSION...CB
AVIATION...NOLTE
FIRE WEATHER...NOLTE
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
917 AM MST SAT NOV 23 2013
.SYNOPSIS...
PACIFIC LOW PRESSURE WILL CONTINUE TO PRODUCE SCATTERED TO NUMEROUS
SHOWERS TODAY FROM PHOENIX EASTWARD...WITH LESSER COVERAGE OVER THE
WESTERN DESERTS. THERE WILL BE A LINGERING CHANCE FOR RAIN
SUNDAY...MAINLY OVER SOUTH-CENTRAL ARIZONA BUT ACCUMULATIONS...IF
ANY...WILL BE MUCH LOWER. HIGH TEMPERATURES WILL REMAIN WELL BELOW
NORMAL THIS WEEKEND. DRY WEATHER AND WARMER TEMPERATURES WILL RETURN
MONDAY THROUGH THE LATTER PART OF NEXT WEEK.
&&
.DISCUSSION...
THE UPPER LOW CENTER HAS STARTED TO MAKE SOME MOVEMENT TO THE
NORTHEAST OVER THE PAST SIX HOURS. THE MAIN BAND OF RAIN HAS ALSO
SHIFTED MORE TO THE EAST AND CURRENTLY RESIDES FROM ACROSS THE FAR
EAST METRO PHOENIX AREA EASTWARD THROUGH GILA COUNTY. RAINFALL RATES
ARE GENERALLY ON THE LIGHT SIDE...OR LESS THAN A TENTH OF AN INCH
PER HOUR. CLOSER TO THE LOW CENTER AND MID LEVEL COOL CORE...HEAVIER
AND MORE SHOWERY TYPE RAIN HAS AFFECTED NORTHEAST MARICOPA COUNTY
SINCE 7 AM. LATEST HRRR MODEL REFLECTIVITY SHOWS THE EASTERN RAIN
BAND EVENTUALLY PUSHING EASTWARD AND WEAKENING THIS AFTERNOON. MORE
SCATTERED SHOWERY TYPE RAIN WILL BE POSSIBLE THROUGHOUT THE DAY
MAINLY FOCUSED ACROSS SOUTHWEST ARIZONA. HAVE TRIMMED BACK ON POPS
FOR THIS AFTERNOON ACROSS THE REST OF THE METRO PHOENIX AREA WHERE
RAIN HAS STOPPED. HOWEVER...UNTIL THE LOW MOVES OUT OF THE AREA
SUNDAY NIGHT...SLIGHT CHANCE TO CHANCE POPS ARE IN THE FORECAST FOR
MUCH OF THE AREA. WILL SEE VERY LITTLE DAYTIME IMPROVEMENT IN
TEMPERATURES...MAYBE INCREASING 5-7 DEGREES IN MOST AREAS FROM
OVERNIGHT LOWS.
&&
.PREVIOUS DISCUSSION...
IMPRESSIVE PACIFIC CLOSED UPPER LOW CONTINUED TO SPIN MORE OR LESS
IN PLACE ALONG THE FAR SERN CA/FAR NRN BAJA COAST AT 3 AM THIS
MORNING...KEEPING A PRONOUNCED DIFLUENT SIGNATURE IN PLACE OVER
ARIZONA. BANDS OF RAIN SHOWERS CONTINUED TO MOVE NORTH ACROSS SOUTH
CENTRAL ARIZONA...HOWEVER THE INTENSITIES WERE LESS THAN WHAT WAS
OBSERVED EARLIER...DURING THE DAY ON FRIDAY. MOST HOURLY RAINFALL
TOTALS HAVE BEEN BELOW ONE TENTH OF AN INCH SINCE MIDNIGHT...AND
LATEST 3 HOURS ACCUMULATIONS FROM THE MARICOPA COUNTY FLOOD CONTROL
GAGES SHOWED VALUES BELOW ONE TENTH OF AN INCH ACROSS WESTERN
MARICOPA COUNTY...AND BETWEEN ONE QUARTER AND ONE HALF INCH OVER THE
GREATER PHOENIX AREA. LITTLE RAINFALL WAS OCCURRING OVER SERN CA AND
THE WESTERN DESERTS...AND IR/VAPOR IMAGERY DEPICTED DRY SLOTTING
OCCURRING OVER OUR WESTERN CWA. PROGS ALL INDICATE THAT THE UPPER
LOW WILL START TO MOVE INLAND TODAY...SHIFTING THE DEEPER MOISTURE
EASTWARD ALONG WITH THE BEST DYNAMICS AND UPPER DIFLUENCE. GIVEN
THAT THE RAINFALL INTENSITIES HAVE BEEN DIMINISHED FOR SOME TIME AND
THAT THERE WILL CONTINUE TO BE DECREASING SHOWERS FROM THE WEST
DURING THE DAY TODAY...WE OPTED TO CANCEL THE FLOOD WATCH EARLY. IT
IS POSSIBLE THAT SMALLER HYDRO ISSUES MAY CROP UP DURING THE
DAY...PROBABLY ACROSS THE EASTERN PORTIONS OF THE GREATER PHOENIX
AREA OR SOUTHERN GILA COUNTY...BUT THEY MOST LIKELY WOULD BE ABLE TO
BE HANDLED WITH FLOOD ADVISORIES. CURRENT POP TRENDS FOR TODAY AND
TONIGHT LOOK GOOD AND FEW CHANGES WERE MADE. EXPECT SLIGHT CHANCES
FOR SHOWERS ACROSS THE WESTERN CWA BY THIS EVENING WITH LINGERING
CHANCES FROM PHOENIX EASTWARD. AS THE LOW EDGES EASTWARD...SOME COLD
AIR ALOFT WILL SHIFT INTO THE WESTERN/CENTRAL DESERTS LEADING TO
SOME INSTABILITY AND A SLIGHT CHANCE FOR EMBEDDED THUNDERSTORMS.
THUS FORECASTS FROM PHOENIX WESTWARD MENTION SLIGHT CHANCES FOR
THUNDER THIS AFTERNOON. EXPECT HIGH TEMPS TODAY TO REMAIN AT LEAST
10 DEGREES BELOW NORMALS...GIVEN THE COOL DAMP AIRMASS IN PLACE AND
THE PERSISTENT CLOUDS AND SHOWERS.
UPPER LOW WILL CONTINUE TO BODILY MOVE EASTWARD ACROSS THE STATE
SUNDAY...LEADING TO A DRYING TREND FROM THE WEST...WITH PRECIP
CHANCES LOWERING TO SLIGHT CHANCES BY AFTERNOON FROM THE GREATER
PHOENIX AREA WESTWARD. MAY SEE AN ISOLATED AFTERNOON THUNDERSTORM
SUNDAY ACROSS THE CENTRAL DESERTS AS THE COLD POOL ALOFT SHIFTS
OVERHEAD. OF COURSE...WITH THE THE MAIN LOW MOVING DIRECTLY
OVERHEAD...TEMPS SUNDAY WILL STAY VERY COOL WITH MOST DESERT LOCALES
STRUGGLING TO REACH INTO THE LOW TO MID 60S.
HIGH PRESSURE WILL BUILD INTO THE AREA FROM THE WEST MONDAY INTO THE
MIDDLE OF NEXT WEEK FOR DRY CONDITIONS AND A WARMING TREND. EXPECT
HIGHS TO CLIMB GRADUALLY...REACHING SEASONAL NORMALS BY TUESDAY
UNDER MOSTLY SUNNY OR SUNNY SKIES.
VARIOUS EXTENDED RANGE MODELS...SUCH AS GFS...ECMWF AND
CANADIAN...AS WELL AS THEIR ENSEMBLES...ALL SUGGEST THAT ANOTHER
PACIFIC LOW PRESSURE SYSTEM MAY IMPACT THE DESERT SOUTHWEST LATER
NEXT WEEK. HOWEVER...ENSEMBLE MEMBER SPREADS ARE EXTREME AND THERE
IS LITTLE RUN TO RUN CONSISTENCY WITH THESE MODELS AND LITTLE MODEL
TO MODEL CONSISTENCY. LATEST GFS MOVES A SIGNIFICANT LOW INTO
ARIZONA BY NEXT FRIDAY...WHILE THE ECMWF CLOSES OFF THE LOW AND
SHIFTS IT WELL OFF THE CA COAST AT THAT TIME. GIVEN MODEL
UNCERTAINTIES...LEFT SOME MODEST POPS ACROSS THE CWA THURSDAY INTO
FRIDAY...MAINLY OVER THE WESTERN DESERTS. POPS ARE NEAR OR A BIT
ABOVE CLIMO. SHOULD THE LATEST EUROPEAN GUIDANCE BE SPOT ON...WE
WILL NOT SEE ANY PRECIP THRU AT LEAST FRIDAY...BUT IT HAS SHOWN
SIGNIFICANT DEVIATIONS RUN TO RUN SO ITS CURRENT SOLUTION CANNOT BE
TRUSTED.
&&
.AVIATION...
SOUTH-CENTRAL AZ...INCLUDING KPHX...KIWA...AND KSDL...
RAIN SHOWER ACTIVITY HAS GRADUALLY DIMINISHED IN AREAL COVERAGE
OVERNIGHT WHILE ALSO TRANSITIONING EAST OF THE PHX METRO. LIGHT
SHOWERS WILL CONTINUE TO STREAM FROM SOUTH TO NORTH GNLY THROUGH
23/1800Z WARRANTING -SHRA MENTION. EARLY MORNING CIGS HAVE THE
POTENTIAL TO BOUNCE BETWEEN VFR AND MVFR LEVELS. CONFIDENCE IS
MODERATE OF CIGS BREAKING OUT IN TO THE 5-6KFT RANGE BY MIDDAY.
SHOWERS WILL BECOME MORE VICINITY IN NATURE BY EVENING AS THEY
TRANSITION FURTHER TO THE EAST. EXPECT PERIODIC TERRAIN OBSCURATIONS
FROM CLOUDS POSSIBLE INTO THE OVERNIGHT HOURS. WINDS WILL GENERALLY
HOLD EAST HEADINGS WITH 8 TO 12 KNOTS OF SPEED POSSIBLE.
SOUTHEAST CALIFORNIA INCLUDING KIPL AND KBLH...
WIDELY SCATTERED LIGHT SHOWER ACTIVITY WILL PERSIST ACROSS SE
CALIFORNIA THROUGH THIS EVENING...PARTICULARLY AT KBLH WHERE MVFR
CIGS/VSBY IMPACTS ARE EXPECTED THROUGH MID MORNING. UPPER LOW
PRESSURE RESPONSIBLE FOR GENERATING THE PRECIP ACTIVITY WILL BEGIN
TO MOVE FURTHER INLAND OVER SOUTHEAST CALIFORNIA...INTRODUCING
COOLER TEMPERATURES ALOFT AND THE POTENTIAL FOR ISOLATED THUNDER
DEVELOPMENT DURING THE AFTERNOON HOURS. CONFIDENCE IS LOW TO
MODERATE FOR ORGANIZED ACTIVITY NEAR THE TERMINALS...SO LEFT ANY
VCTS OR CB MENTION OUT OF THE 12Z TAF PACKAGE.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
MONDAY THROUGH FRIDAY...
LOW PRESSURE WILL CONTINUE TO EXIT TO THE EAST MONDAY...LEAVING WELL
BELOW NORMAL TEMPERATURES AND A DRYING TREND IN TERMS OF
PRECIPITATION. COLDER AIR WILL LIE AGAINST THE CONTINENTAL DIVIDE
THROUGH MIDWEEK...KEEPING SURFACE GRADIENTS TIGHTENED AND MORE
PRONOUNCED EASTERLY WINDS DEVELOPING ACROSS EASTERN AND CENTRAL
ARIZONA. HIGH PRESSURE WILL BUILD ACROSS THE REGION...RESULTING IN A
WARMING TREND THROUGH MIDWEEK AND A RETURN TO NEAR NORMAL
TEMPERATURES BY TUESDAY. LATER INTO NEXT WEEK ANOTHER STORM SYSTEM
IS FORECAST TO DEVELOP OFF THE PACIFIC BRINGING WITH IT COOLER
TEMPERATURES FOR THE LATE WEEK AND POTENTIALLY ANOTHER ROUND OF
RAIN/SNOW SHOWER ACTIVITY TO THE REGION BY NEXT WEEKEND.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...KUHLMAN
PREVIOUS DISCUSSION...CB
AVIATION...NOLTE
FIRE WEATHER...NOLTE
AREA FORECAST DISCUSSION
NWS PUEBLO CO
620 PM MST SUN NOV 24 2013
.UPDATE...
ISSUED AT 611 PM MST SUN NOV 24 2013
UPDATED SNOW GRIDS TO INCREASE AMOUNTS. BAND HAS BEEN PRODUCING A
QUICK 1 TO 4 INCHES ACROSS EL PASO AND PUEBLO COUNTIES. WITH
TRAJECTORY OF SNOW ENHANCEMENT HEADED TOWARDS THE WET
MOUNTAINS...ADDED THE LOWER ELEVATIONS OF THE WETS AND THE LOWER
ELEVATIONS OF THE SANGRES TO THE WINTER WEATHER ADVISORY. HAVE AN
SPS OUT FOR EL PASO AND PUEBLO COUNTIES FOR NOW. ITS POSSIBLE THAT
THESE AREAS MAY NEED TO BE UPGRADED TO AN ADVISORY...BUT THE VAST SPATIAL
VARIABILITY BETWEEN THE HEAVY SNOW AND WHERE THERE IS NO SNOW
ACROSS THESE ZONES MAKES THIS A LESS FAVORABLE OPTION FOR
NOW...BUT WILL CONTINUE TO MONITOR AND REASSESS AS NEEDED. -KT
UPDATE ISSUED AT 459 PM MST SUN NOV 24 2013
QUICK UPDATE TO BUMP UP POPS ACROSS EL PASO AND NORTHWEST PUEBLO
COUNTIES WHERE DEFORMATION BAND HAS SET UP. GETTING REPORTS OF MODERATE
SNOW WITHIN THIS BAND AND SUSPECT A QUICK INCH OR TWO WILL BE
POSSIBLE WITHIN THE NEXT HOUR OR TWO. BASED ON SHORT RANGE HIGH RES
MODELS...FOCUS FOR HEAVIER SNOWFALL WILL SHIFT INTO THE NORTHEAST
FACING SLOPES OF THE SOUTHEAST MOUNTAINS AND FREMONT COUNTY AS THE
EVENING PROGRESSES. HOWEVER MODELS ARE NOT RESOLVING THE CURRENT
SNOW BAND VERY WELL...SO EXPECT A HIGHLY EVOLVING FORECAST TONIGHT
AS THESE DETAILS GET RESOLVED. FOR NOW...HAVE BUMPED UP POPS INTO
THE LIKELY CATEGORY FOR EL PASO...FREMONT...AND WESTERN PUEBLO
COUNTIES THROUGH 06Z. IF BAND STALLS OVER ANY PARTICULAR
AREA...SOME LOCAL ACCUMULATIONS OF UP TO 4 INCHES WILL BE POSSIBLE
OVER THE LOWER ELEVATIONS. -KT
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 241 PM MST SUN NOV 24 2013
...SNOW WINDING DOWN ON MONDAY...
UPPER LOW IS NOW NOW MOVING EASTWARD ALONG THE CO NM BORDER. COLDER CLOUD
TOPS HAVE SHIFTED TO THE NE PORTION OF CO...WHERE SEVERAL BANDS OF
SNOW ARE ROTATING NORTHWESTWARD ALONG THE NRN I-25 CORRIDOR. THE LOW HAS
DEFINITELY TAKEN A MORE NRN TRACK AS THE NAM AND ESPECIALLY THE
ECMWF HAD FORECAST IT TO DO. HOWEVER...NOT A LOT OF MOISTURE LEFT
WITH THE SYSTEM...AND ACCUMS TONIGHT INTO MON MORNING PROBABLY WILL
NOT BE ALL THAT IMPRESSIVE. MAIN FOCUS FOR HEAVIER ACCUMS WILL BE
DUE TO N-NE WINDS INCREASING TONIGHT AS THE LOW CONTINUES TO MOVE
AWAY. LATEST RUC SHOWING H7 WINDS INCREASING TO 30-40 KTS AFTER
ABOUT 04Z TONIGHT. THIS WILL LEAD TO SOME DECENT OROGRAPHIC ACCUMS
OVER THE HIGHER ELEVATIONS OF THE ERN MT RANGES OVERNIGHT...AND
FAVORED SPOTS LIKE CUCHARA COULD SEE SOME RESPECTABLE SNOWFALL.
LATEST HI RES MODELS REALLY SHOWING THIS POTENTIAL OVER THE WETS AND
NRN SANGRES...SO WILL ADD THE WETS TO THE CURRENT SUITE OF
ADVISORIES WE HAVE OUT THROUGH 12Z MONDAY. ELSEWHERE...BEST BET OF
SNOW OVER THE PLAINS WILL BE ALONG AND WEST OF I-25...AND ESPECIALLY
SOUTH OF HIGHWAY 50. COULD SEE SOME LIGHT ACCUMS OVER THE HIGHER
TRRN BUT NOT EXPECTING ANYTHING SIGNIFICANT. INHERITED LOW POPS FOR
THE PLAINS STILL LOOK ON TARGET SO HAVE NOT MADE ANY EXTENSIVE
CHANGES THERE.
SHOULD SEE SNOW TAPER OFF FROM N TO S ESPECIALLY AFTER MID-MORNING
ON MONDAY. JUST A FEW LINGERING SHOWERS OVER THE SRN MTS AND FAR
SERN PLAINS BY MON AFTERNOON. BREEZY CONDITIONS WILL PERSIST IN THE
WAKE OF THE LOW...ESPECIALLY OVER BACA COUNTY WHICH COULD SEE SOME
GUSTS IN THE 30-40 KT RANGE FOR THE LATE MORNING TO EARLY AFTERNOON
PERIOD. TEMPS ALOFT WILL ACTUALLY BE FALLING SIGNIFICANTLY THROUGH
MONDAY MORNING...DOWN TO AROUND MINUS 7 OR 8 C AT H7...BUT WITH GOOD
MIXING IN THE LOW TO MID LEVELS...SHOULD SEE TEMPS TOP OUT HIGHER
THAN THE TEMPS THIS AFTERNOON. HAVE CUT BACK TEMPS A BIT BELOW
GUIDANCE HOWEVER...SINCE EVEN WITH GOOD ADIABATIC MIXING THE TEMPS
ALOFT WILL PROBABLY ONLY SUPPORT 40 DEGREES OR SO AT BEST BY THE
AFTERNOON. SO...IT WILL BE A RAW DAY DESPITE THE LOWERED POPS.
ROSE
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 241 PM MST SUN NOV 24 2013
MONDAY NIGHT...UPPER LOW OVER WEST TEXAS FORECAST BY MODELS TO SLIDE
SOUTHEAST...BUT SOME MOISTURE IN NORTHERLY FLOW ALOFT WILL PERSIST
THROUGH PART OF THE NIGHT. INHERITED ISOLATED POPS AT MOST OVER THE
EASTERN MOUNTAINS THROUGH MIDNIGHT...AND THAT LOOKS GOOD. SNOW
ACCUMULATIONS WILL BE WELL UNDER AN INCH. LOW TEMPERATURES WILL BE
IN THE LOWER SINGLE DIGITS ACROSS THE SAN LUIS VALLEY...WITH SNOW
COVER AND RADIATIONAL COOLING. ELSEWHERE...TEMPERATURES SHOULD DIP
INTO THE TEENS ACROSS THE PLAINS AND OTHER HIGH VALLEYS...WITH
SINGLE DIGITS ACROSS THE HIGHEST ELEVATIONS.
FOR THE REMAINDER OF THE WEEK AND INTO NEXT WEEKEND...THE WEATHER
LOOKS TO BE FAIRLY TRANQUIL...AS AN UPPER LEVEL RIDGE GETS
ESTABLISHED OVER THE GREAT BASIN AND ROCKIES. A WEAK FRONT MAY
BRIEFLY AFFECT THE EASTERN PLAIN THANKSGIVING DAY...BUT WITH NO
PRECIPITATION. A COUPLE MORE SHORTWAVES IN THE NORTHERN
STREAM...WILL BRING SOME CLOUDS...WITH THE SECOND ONE...DURING THE
WEEKEND...BRINGING A CHANCE FOR SOME HIGHER ELEVATION SNOW SHOWERS.
-TLM-
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY AFTERNOON)
ISSUED AT 241 PM MST SUN NOV 24 2013
SNOW SHOWERS LINGERING OVER NRN EL PASO COUNTY SHOULD CONTINUE TO
MOVE OFF TO THE NW LATE THIS AFTERNOON. NO SIGNIFICANT ACCUMULATIONS
ARE EXPECTED WITH THIS ACTIVITY. KCOS COULD SEE ANOTHER ROUND OF
INTERMITTENT LIGHT SN LATER THIS EVE...BUT IT SHOULD NOT LAST LONG
AND SHOULD NOT LINGER MUCH BEYOND 12Z MON. KPUB WILL SEE CHANCES OF
SNOW LINGER A BIT LONGER INTO MON MORNING...BUT NOT EXPECTING MUCH
IN THE WAY OF ACCUMULATIONS THERE EITHER. IT CURRENTLY LOOKS LIKE
MOST OF THE HEAVIER SNOWFALL OVERNIGHT WILL STAY SOUTH OF HIGHWAY 50.
KALS WILL SEE A GOOD CHANCE OF LIGHT SNOW THROUGH THIS EVE AND
OVERNIGHT...WITH LIGHT ACCUMS OF A COUPLE INCHES POSSIBLE BY EARLY
MONDAY. SHOULD SEE CONDITIONS IMPROVE FROM NW TO SE THROUGH
MONDAY...WITH JUST SOME LINGERING SHOWERS OVER THE HYR TRRN. MAIN
STORY TOMORROW WILL BE THE INCREASED N-NE WINDS...WHICH WILL REMAIN
GUSTY OVER THE PLAINS THROUGH THE EARLY AFTERNOON BEFORE QUIETING
DOWN LATER IN THE DAY. ROSE
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 5 AM MST MONDAY FOR COZ060-066-
072>075-079-080.
WINTER STORM WARNING UNTIL 5 AM MST MONDAY FOR COZ068.
&&
$$
UPDATE...KT
SHORT TERM...ROSE
LONG TERM...TM
AVIATION...ROSE
AREA FORECAST DISCUSSION
NWS PUEBLO CO
510 PM MST SUN NOV 24 2013
.UPDATE...
ISSUED AT 459 PM MST SUN NOV 24 2013
QUICK UPDATE TO BUMP UP POPS ACROSS EL PASO AND NORTHWEST PUEBLO
COUNTIES WHERE DEFORMATION BAND HAS SET UP. GETTING REPORTS OF MODERATE
SNOW WITHIN THIS BAND AND SUSPECT A QUICK INCH OR TWO WILL BE
POSSIBLE WITHIN THE NEXT HOUR OR TWO. BASED ON SHORT RANGE HIGH RES
MODELS...FOCUS FOR HEAVIER SNOWFALL WILL SHIFT INTO THE NORTHEAST
FACING SLOPES OF THE SOUTHEAST MOUNTAINS AND FREMONT COUNTY AS THE
EVENING PROGRESSES. HOWEVER MODELS ARE NOT RESOLVING THE CURRENT
SNOW BAND VERY WELL...SO EXPECT A HIGHLY EVOLVING FORECAST TONIGHT
AS THESE DETAILS GET RESOLVED. FOR NOW...HAVE BUMPED UP POPS INTO
THE LIKELY CATEGORY FOR EL PASO...FREMONT...AND WESTERN PUEBLO
COUNTIES THROUGH 06Z. IF BAND STALLS OVER ANY PARTICULAR
AREA...SOME LOCAL ACCUMULATIONS OF UP TO 4 INCHES WILL BE POSSIBLE
OVER THE LOWER ELEVATIONS. -KT
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 241 PM MST SUN NOV 24 2013
...SNOW WINDING DOWN ON MONDAY...
UPPER LOW IS NOW NOW MOVING EASTWARD ALONG THE CO NM BORDER. COLDER CLOUD
TOPS HAVE SHIFTED TO THE NE PORTION OF CO...WHERE SEVERAL BANDS OF
SNOW ARE ROTATING NORTHWESTWARD ALONG THE NRN I-25 CORRIDOR. THE LOW HAS
DEFINITELY TAKEN A MORE NRN TRACK AS THE NAM AND ESPECIALLY THE
ECMWF HAD FORECAST IT TO DO. HOWEVER...NOT A LOT OF MOISTURE LEFT
WITH THE SYSTEM...AND ACCUMS TONIGHT INTO MON MORNING PROBABLY WILL
NOT BE ALL THAT IMPRESSIVE. MAIN FOCUS FOR HEAVIER ACCUMS WILL BE
DUE TO N-NE WINDS INCREASING TONIGHT AS THE LOW CONTINUES TO MOVE
AWAY. LATEST RUC SHOWING H7 WINDS INCREASING TO 30-40 KTS AFTER
ABOUT 04Z TONIGHT. THIS WILL LEAD TO SOME DECENT OROGRAPHIC ACCUMS
OVER THE HIGHER ELEVATIONS OF THE ERN MT RANGES OVERNIGHT...AND
FAVORED SPOTS LIKE CUCHARA COULD SEE SOME RESPECTABLE SNOWFALL.
LATEST HI RES MODELS REALLY SHOWING THIS POTENTIAL OVER THE WETS AND
NRN SANGRES...SO WILL ADD THE WETS TO THE CURRENT SUITE OF
ADVISORIES WE HAVE OUT THROUGH 12Z MONDAY. ELSEWHERE...BEST BET OF
SNOW OVER THE PLAINS WILL BE ALONG AND WEST OF I-25...AND ESPECIALLY
SOUTH OF HIGHWAY 50. COULD SEE SOME LIGHT ACCUMS OVER THE HIGHER
TRRN BUT NOT EXPECTING ANYTHING SIGNIFICANT. INHERITED LOW POPS FOR
THE PLAINS STILL LOOK ON TARGET SO HAVE NOT MADE ANY EXTENSIVE
CHANGES THERE.
SHOULD SEE SNOW TAPER OFF FROM N TO S ESPECIALLY AFTER MID-MORNING
ON MONDAY. JUST A FEW LINGERING SHOWERS OVER THE SRN MTS AND FAR
SERN PLAINS BY MON AFTERNOON. BREEZY CONDITIONS WILL PERSIST IN THE
WAKE OF THE LOW...ESPECIALLY OVER BACA COUNTY WHICH COULD SEE SOME
GUSTS IN THE 30-40 KT RANGE FOR THE LATE MORNING TO EARLY AFTERNOON
PERIOD. TEMPS ALOFT WILL ACTUALLY BE FALLING SIGNIFICANTLY THROUGH
MONDAY MORNING...DOWN TO AROUND MINUS 7 OR 8 C AT H7...BUT WITH GOOD
MIXING IN THE LOW TO MID LEVELS...SHOULD SEE TEMPS TOP OUT HIGHER
THAN THE TEMPS THIS AFTERNOON. HAVE CUT BACK TEMPS A BIT BELOW
GUIDANCE HOWEVER...SINCE EVEN WITH GOOD ADIABATIC MIXING THE TEMPS
ALOFT WILL PROBABLY ONLY SUPPORT 40 DEGREES OR SO AT BEST BY THE
AFTERNOON. SO...IT WILL BE A RAW DAY DESPITE THE LOWERED POPS.
ROSE
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 241 PM MST SUN NOV 24 2013
MONDAY NIGHT...UPPER LOW OVER WEST TEXAS FORECAST BY MODELS TO SLIDE
SOUTHEAST...BUT SOME MOISTURE IN NORTHERLY FLOW ALOFT WILL PERSIST
THROUGH PART OF THE NIGHT. INHERITED ISOLATED POPS AT MOST OVER THE
EASTERN MOUNTAINS THROUGH MIDNIGHT...AND THAT LOOKS GOOD. SNOW
ACCUMULATIONS WILL BE WELL UNDER AN INCH. LOW TEMPERATURES WILL BE
IN THE LOWER SINGLE DIGITS ACROSS THE SAN LUIS VALLEY...WITH SNOW
COVER AND RADIATIONAL COOLING. ELSEWHERE...TEMPERATURES SHOULD DIP
INTO THE TEENS ACROSS THE PLAINS AND OTHER HIGH VALLEYS...WITH
SINGLE DIGITS ACROSS THE HIGHEST ELEVATIONS.
FOR THE REMAINDER OF THE WEEK AND INTO NEXT WEEKEND...THE WEATHER
LOOKS TO BE FAIRLY TRANQUIL...AS AN UPPER LEVEL RIDGE GETS
ESTABLISHED OVER THE GREAT BASIN AND ROCKIES. A WEAK FRONT MAY
BRIEFLY AFFECT THE EASTERN PLAIN THANKSGIVING DAY...BUT WITH NO
PRECIPITATION. A COUPLE MORE SHORTWAVES IN THE NORTHERN
STREAM...WILL BRING SOME CLOUDS...WITH THE SECOND ONE...DURING THE
WEEKEND...BRINGING A CHANCE FOR SOME HIGHER ELEVATION SNOW SHOWERS.
-TLM-
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY AFTERNOON)
ISSUED AT 241 PM MST SUN NOV 24 2013
SNOW SHOWERS LINGERING OVER NRN EL PASO COUNTY SHOULD CONTINUE TO
MOVE OFF TO THE NW LATE THIS AFTERNOON. NO SIGNIFICANT ACCUMULATIONS
ARE EXPECTED WITH THIS ACTIVITY. KCOS COULD SEE ANOTHER ROUND OF
INTERMITTENT LIGHT SN LATER THIS EVE...BUT IT SHOULD NOT LAST LONG
AND SHOULD NOT LINGER MUCH BEYOND 12Z MON. KPUB WILL SEE CHANCES OF
SNOW LINGER A BIT LONGER INTO MON MORNING...BUT NOT EXPECTING MUCH
IN THE WAY OF ACCUMULATIONS THERE EITHER. IT CURRENTLY LOOKS LIKE
MOST OF THE HEAVIER SNOWFALL OVERNIGHT WILL STAY SOUTH OF HIGHWAY 50.
KALS WILL SEE A GOOD CHANCE OF LIGHT SNOW THROUGH THIS EVE AND
OVERNIGHT...WITH LIGHT ACCUMS OF A COUPLE INCHES POSSIBLE BY EARLY
MONDAY. SHOULD SEE CONDITIONS IMPROVE FROM NW TO SE THROUGH
MONDAY...WITH JUST SOME LINGERING SHOWERS OVER THE HYR TRRN. MAIN
STORY TOMORROW WILL BE THE INCREASED N-NE WINDS...WHICH WILL REMAIN
GUSTY OVER THE PLAINS THROUGH THE EARLY AFTERNOON BEFORE QUIETING
DOWN LATER IN THE DAY. ROSE
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 5 AM MST MONDAY FOR COZ060-066-
073>075-080.
WINTER STORM WARNING UNTIL 5 AM MST MONDAY FOR COZ068.
&&
$$
UPDATE...KT
SHORT TERM...ROSE
LONG TERM...TM
AVIATION...ROSE
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
311 PM MST SAT NOV 23 2013
.SHORT TERM...(TONIGHT THROUGH SUNDAY NIGHT)
ISSUED AT 311 PM MST SAT NOV 23 2013
COMPLEX PATTERN TODAY AS COLDER AIR MOVED INTO SOUTHEAST
UTAH...LOWERING THE SNOW LEVELS TO THE VALLEY FLOORS. BUT
SOUTHWEST COLORADO HAS STAYED IN THE WARM SECTOR WITH THE SNOW
LEVEL AROUND 8000 FEET. TELLURIDE AWOS OBSERVED LIGHT RAIN EARLIER
TODAY. SOUTHWEST COLORADO HAS BEEN A CHALLENGE WITH RESPECT TO
PRECIPITATION TYPE DURING THE PAST DAY OR TWO. CONFIDENCE IS
INCREASING THAT SNOW LEVELS WILL LOWER TO THE VALLEY FLOORS
(EXCEPT SOUTH OF CORTEZ) AS THE MOIST CONVEYOR BELT OVER ERN
ARIZONA SHIFTS INTO NWRN NEW MEXICO INTO EXTREME SWRN COLORADO.
MID LEVEL TEMPS IN THE CONVEYOR BELT IS COLDER AND DIABATIC COOLING
PROCESSES WILL RESULT IN RAIN CHANGING OVER TO SNOW. WITH SOUTHEAST
LOW LEVEL FLOW...THE RAP AND DOWNSCALED 5KM NAM SHOW THE QPF
BULLSEYE ALONG THE MONTEZUMA/LA PLATA COUNTY LINE AND MONTICELLO
UTAH WITH AREAS EXCEEDING 1 INCH OF PCPN DURING THE NEXT 12 HOURS.
THIS EQUATES TO A SNOW ACCUMULATION OF 6-12 INCHES OF "SIERRA
CEMENT" (HEAVY WET SNOW) FOR THE THIS AREA OVERNIGHT.
FOR EAST CENTRAL UTAH AND THE UNCOMPAHGRE/GRAND VALLEY...SOUTHEAST
FLOW WILL A WARMING EFFECT THAT ERODES THE COLDER SURFACE AIR.
THIS ELIMINATES THE CHANCE OF A REPEAT PERFORMANCE OF HEAVY SNOW
FROM CANYONLANDS NATIONAL PARK TO DEBEQUE CANYON. THE OVERRUNNING
PATTERN WILL NO LONGER EXIST AND THE AREAL EXTENT OF PRECIPITATION
WILL HAVE LESSENED. FARTHER NORTH...MOSTLY DRY ALTHOUGH SOME
DISSIPATING BANDS OF LIGHT SNOW MAY GENERATE FLURRIES OVER NE
UTAH/NW COLORADO.
SUNDAY AND SUNDAY NIGHT...THE CLOSED UPPER LOW WILL BE WEAKENING
AS IT MOVES INTO NWRN NEW MEXICO. ACTIVE WEATHER WILL STILL EXIST
BENEATH THE UPPER LOW SO ACCUMULATING SNOW CONTINUES ACROSS SW
COLORADO. BUT THE MOISTURE FIELD OVER ERN UTAH AND NORTHWEST
COLORADO WILL BE ERODING. AS THE LOW CONTINUES TO TRACK ACROSS NEW
MEXICO...LOW LEVEL FLOW BECOMES NORTHWEST THAT FAVORS THE NWRN SAN
JUANS AND THE SRN UNCOMPAHGRE PLATEAU (DALLAS DIVIDE/RIDGWAY AND
OURAY). BUT SNOW RATES WILL BE DIMINISHING AS THE UPPER LOW WILL
BE MOVING DOWNSTREAM. BY THE TIME THE UPPER LOW DOES DEPART THE
REGION LATE SUNDAY NIGHT...STORM TOTAL QPF AND SNOWFALL WILL BE
QUITE IMPRESSIVE FOR THE SRN PORTION OF THE FORECAST AREA.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 311 PM MST SAT NOV 23 2013
THE UPPER LOW WILL HAVE TRANSLATED THE ROCKIES TO NEAR THE TEXAS
PANHANDLE BY SUNRISE ON MONDAY...THEN BE FORCED SOUTHWARD BY A
STRONG DIP IN THE NORTHERN STREAM ACROSS THE UPPER MISSISSIPPI
VALLEY. LINGERING WRAP AROUND MOISTURE WILL BE EXITING THE FAR
SOUTHERN CWA LATE BY MORNING AS THE UPPER LOW BEGINS TO BE FORCED
SOUTHWARD. THE RETREATING MOISTURE WILL BE REPLACED BY ANOTHER BATCH
OF HIGH LEVEL MOISTURE BEING TRANSPORTED IN ON THE NORTHERLY STREAM.
NAM/GFS DIFFERING A BIT WITH THE GFS SATURATING THE UPPER END OF THE
DENDRITIC LAYER NEAR 500MB. THE NAM A BIT MORE AGGRESSIVE WITH
SATURATION DOWN TO THE TOP OF THE NORTHERN DIVIDE MOUNTAINS THROUGH
A LARGER PORTION OF THE DENDRITIC LAYER. ASCENT IS WEAK WITH
OROGRAPHICS THE MAIN DRIVER IN THE NORTH FLOW SO WOULD EXPECT ANY
ACCUMULATIONS TO BE ON THE LIGHT SIDE. FOR NOW WILL KEEP JUST
SOME SMALL POPS IN PLACE THROUGH THE AFTERNOON UNTIL MODEL
AGREEMENT ALIGNS BETTER. TEMPERATURES ARE SURE TO BE AFFECTED BY
THE SNOW COVER ESPECIALLY OVER SOUTHEAST UTAH INTO SOUTHWEST
COLORADO SO UNDERCUT GUIDANCE NUMBERS IN MANY AREAS.
THERE SHOULD BE SLOW WARM-UP GOING INTO THE MID TO LATE WEEK PERIOD
THOUGH THE STRONG NORTHERN STREAM FLOW JUST OFF TO OUR NORTHEAST
WILL CONTINUE TO RE-ENFORCE THE COLD AIR ALOFT. VALLEY INVERSIONS
WITH THE SNOW PACK WILL CONTINUE TO PUT A DAMPER ON WARMING SO AGAIN
TEMPERATURES FROM BLENDED MODELS WERE LOWERED. A WEAK WAVE PASSAGE
ON THURSDAY MAY BRING A BIT A PASSING HIGH CLOUDINESS BUT IS NOT
LIKELY TO ADD MUCH TO MIXING. OUT WEST THE EASTERN PACIFIC TROF WILL
BE SPLITTING WITH ONE BATCH CATCHING THE WESTERLIES ACROSS THE
NORTHERN CONUS BORDER. THE OTHER MAIN BATCH WILL CLOSE OFF ANOTHER
LOW ALONG THE CALIFORNIA COASTLINE. SOME OF THIS SOUTHERN ENERGY
SHEARS OUT OF THE LOW AND PROGRESSES ACROSS THE CENTRAL ROCKIES
PULLING MOISTURE WITH IT. FOR NOW IT SEEMS THIS WILL BE MAINLY IN
THE FORM OF HIGH CLOUDINESS THROUGH THE LATE WEEK PERIOD. SO FOR NOW
A MAINLY DRY FORECAST LOOKS ON TRACK FOR HOLIDAY TRAVEL WITH
TEMPERATURES GRADUALLY WARMING.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 311 PM MST SAT NOV 23 2013
ANOTHER BATCH OF ENERGY AND MOISTURE IS LIFTING ACROSS SOUTHWEST
COLORADO AND FAR EASTERN UTAH THIS AFTERNOON...BUT IS MIXING IN
WITH A BIT OF DRIER AIR ALOFT. THIS IS LEAVING A MORE SHOWERY FEEL
TO PRECIPITATION WITH VFR CONDITIONS OVER MANY OF THE FORECAST
TERMINALS LATE THIS AFTERNOON. THE STRONGER MOISTURE IS JUST TO
THE WEST OF THE 4 CORNERS AND IS AIDING IN SNOW AND LOW CLOUDINESS
OVER THE KCNY TERMINAL. MOIST UPSLOPE FLOW IS ALSO KEEPING MVFR
CIGS PUSHED UP AGAINST THE SOUTHERN SAN JUANS AND THE KDRO
TERMINAL. THE WESTERN MOISTURE PLUME WILL BE SPREADING EASTWARD
OVERNIGHT AND EXPECT DETERIORATING FLIGHT CONDITIONS OVER MANY OF
THE TAF SITES OVERNIGHT WITH THE BIGGEST IMPACTS OVER KDRO...KTEX
CLOSER TO THE CORE OF THE PASSING STORM SYSTEM TO THE SOUTH.
MOUNTAIN OBSCURATION WILL BE PROMINENT OVER MANY AREAS THROUGH
SUNDAY NIGHT BEFORE SOME DRYING BEGINS TO PUSH IN FROM THE NORTH.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...WINTER STORM WARNING UNTIL 3 AM MST MONDAY FOR COZ018-019.
WINTER WEATHER ADVISORY UNTIL NOON MST SUNDAY FOR COZ021.
WINTER STORM WARNING UNTIL NOON MST SUNDAY FOR COZ022-023.
UT...WINTER STORM WARNING UNTIL 3 AM MST MONDAY FOR UTZ028.
WINTER WEATHER ADVISORY UNTIL NOON MST SUNDAY FOR UTZ029.
&&
$$
SHORT TERM...PF
LONG TERM...15
AVIATION...15
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
943 AM MST SAT NOV 23 2013
.UPDATE...
ISSUED AT 852 AM MST SAT NOV 23 2013
COMPLEX SCENARIO THIS MORNING AND PRECIPITATION TYPE IS DETERMINED
BY THE POSITIONING OF SHALLOW COLD FRONT. HEAVY WET SNOW HAS
TAPERED OFF OVER EAST CENTRAL UTAH INTO WEST CENTRAL COLORADO. BUT
THE COLDER AIR NEVER REACHED THE SRN VALLEYS WITH RAIN AT DURANGO
AND MIXED RAIN/SNOW AT PAGOSA SPRINGS. ELECTED TO CANCEL THE
WEATHER WEATHER ADVISORY OR WINTER STORM WARNING FOR THE SRN
VALLEYS. HEAVY SNOW IS STILL POSSIBLE FOR THE SWRN COLORADO
VALLEYS...BUT NOT DURING THE NEXT SEVERAL HOURS.
PROMINENT CLOSED UPPER LOW OVER SRN CALIFORNIA WILL CONTINUE TO
SEND MOISTURE ACROSS THE REGION THROUGH SUNDAY. MOIST CONVEYOR
BELT IS NOTED OVER ARIZONA INTO SRN UTAH AND THIS ACTIVITY WILL
SLOWLY SHIFT EAST. PRECIPITATION TYPE REMAINS A CHALLENGE AND WILL
NEED TO MAKE AN ASSESSMENT...BUT ANY SNOW THAT FALLS WILL BE
CLOSER ALIGNED AS "SIERRA CEMENT" RATHER THAN THE TYPICAL POWDERY
FLUFF THAT WESTERN COLORADO TYPICALLY RECEIVES. FOR THE I70
CORRIDOR WHERE HEAVY WET SNOW FELL...CURRENT GUIDANCE SUGGEST THAT
THE COLDER SURFACE TEMPS WILL MODERATE AND THAT SNOW WILL CHANGE
OVER TO RAIN. NOT FULLY CONFIDENT WITH THIS SOLUTION BUT SEEMS
REASONABLE IF DEW POINTS CLIMB INTO THE MID 30S. LOTS OF FORECAST
QUESTIONS TODAY AS THIS WINTER STORM CONTINUES TO EVOLVE.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 438 AM MST SAT NOV 23 2013
UPPER LEVEL LOW CONTINUES TO PUMP MOISTURE INTO OUR REGION...OVERRUNNING
COLD AIR AT THE SURFACE AND PRODUCING HEAVY WET SNOW. EXPECTING
TEMPS TO STAY SOMEWHAT HINDERED TODAY...AS CLOUD COVER WITH
INTERMITTENT BANDS OF SNOW CONTINUES AND NOW A COLD SNOW-COVERED
SURFACE IS PRESENT IN MANY AREAS. MANY NORMALLY ARID AREAS
RECEIVED NOTABLE AMOUNTS OF SNOW OVERNIGHT INCLUDING OVER 5 INCHES
JUST SOUTH OF MOAB AND OVER 3 INCHES AT GRAND JUNCTION AS OF
MIDNIGHT WITH LIGHT TO MODERATE SNOW CONTINUING SINCE. THAT BEING
SAID...SNOW LEVELS IN THE SOUTHERN CWA HAVE NOT REACHED VALLEY
FLOORS...KEEPING BOTH CORTEZ AND DURANGO IN RAIN INSTEAD OF
CHANGING OVER TO SNOW. NOT EXPECTING THIS TO CHANGE
TODAY...ESPECIALLY WITH WARM AIR CONTINUING TO PUMP UP INTO THE
REGION AT MID LEVELS.
CURRENT RADAR SHOWS BAND OF MODERATE SNOW FROM MOAB NORTHEAST TO
EAGLE. TRICKY ADVISORY/WARNING EVENTS THIS WEEKEND...AS SNOW IS
COMING IN WAVES. KEPT ADVISORIES OUT FOR THE GRAND VALLEY AND I-70
CORRIDOR TO EDWARDS UNTIL 11AM AS THE SNOW CONTINUES TO COME DOWN
IN LIGHT TO MODERATE RATES. CAN ALREADY SEE MORE LIGHT ECHOES
ON RADAR MOVING INTO THE NORTHERN SAN JUANS MTNS. FAVORING A
BLEND OF THE RAP AND NAM12 IN THE SHORT TERM AS THE RAP IS
IDENTIFYING SMALLER SCALE FEATURES BUT THE NAM IS BETTER ON
TIMING. THAT BEING SAID...THE BEST CHANCE OF SNOWFALL BY LATE
MORNING TODAY WILL BE DOWN IN THE FOUR CORNERS AREA. THIS
PRECIPITATION WILL GRADUALLY MOVE NORTHEAST THROUGHOUT THE
AFTERNOON AND IS EXPECTED TO REACH THE GRAND VALLEY AND I-70
CORRIDOR AGAIN BY THIS EVENING. DECIDED TO NOT PUT OUT ANY NEW
ADVISORIES AT THIS POINT SINCE SNOWFALL AMTS LOOK TO BE LESS THAN
THIS ONGOING FRI NIGHT/SAT MORNING EVENT...BUT DEFINITELY
SOMETHING THAT WE WILL BE KEEPING AN EYE ON. THE UPPER LEVEL JET
MOVES EAST TONIGHT...WHICH WILL BE ONE LESS FACTOR TO HELP
SMPLIFY THE SNOWFALL RATES TODAY. DYNAMICAL LIFTING AHEAD OF THE
LOW PRESSURE REMAINS DECENT FOR CONTINUATION OF SNOW PRODUCTION
THROUGH A WELL-SATURATED ENVIRONMENT.
THE FUN CONTINUES THROUGH SUNDAY AS THE UPPER LEVEL LOW FINALLY
ACCELERATES EAST OVER THE FOUR CORNERS BY SUNDAY EVENING. AS THE
LOW PROCEEDS EAST... WRAPAROUND MOISTURE AIDED BY DISTURBANCES
WITHIN THE SYSTEM WILL CONTINUE UNTIL THE ENTIRETY IS OUT OF THE
REGION FOR THE EARLY WORKWEEK.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 438 AM MST SAT NOV 23 2013
SHOULD NOTICE A DIMINISH IN PRECIPITATION BY SUNDAY NIGHT IN ALL
AREAS BUT THE CENTRAL TO EASTERN SAN JUAN MTNS UP INTO THE
GUNNISON VALLEY WHICH WILL LIKELY CONTINUE THROUGH MONDAY MORNING.
MONDAY THROUGH FRIDAY...ON MONDAY THE LOW CENTER WILL HAVE MOVED
TO NE NM AND INTO THE TX/OK PANHANDLES. NORTH TO NORTHEAST FLOW
ALOFT WILL SPREAD ACROSS THE AREA AND PCPN WILL BE CONFINED TO THE
CO SW MTS AND THE CONTINENTAL DIVIDE IN THE NORTHERN AND CENTRAL
CO MTS. CLEARING SKIES AND DRYING CONDITIONS WILL SPREAD EAST FROM
EASTERN UT. A SHARP RIDGE WILL BUILD OVER THE GREAT BASIN MON NIGHT
AND MOVE EAST...WITH THE UPPER RIDGELINE PASSING OVER EASTERN UT
AND WESTERN CO ON WED. THURSDAY AND FRIDAY THE PATTERN TRANSITIONS
FROM THE DOMINANT RIDGE OVER THE WEST TO THE NEXT BIG PACIFIC
TROUGH...WHICH THE MIDRANGE MODELS MOVE ONSHORE OVER NORTHERN
CALIFORNIA ON FRIDAY. SW WINDS ALOFT WILL INCREASE OVER THE
FORECAST AREA FRIDAY WITH INCREASING CLOUDS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 943 AM MST SAT NOV 23 2013
ANOTHER BATCH OF MOISTURE IS MOVING NORTHWARD ACROSS THE SOUTHERN
UTAH AND COLORADO LINE. MIXED PRECIPITATION IS POSSIBLE IN THIS
BAND WHICH LOOK TO AFFECT THE KCNY AND KGJT TERMINALS THROUGH THE
EARLY PORTION OF THE FORECAST. STRATUS AND LOW CLOUDS ARE
CURRENTLY AFFECTING THE KASE AND KMTJ TERMINALS. EXPECT SOME
IMPROVEMENT FROM THESE SITES THROUGH EARLY AFTERNOON...THOUGH
PASSING SHOWERS NEAR KMTJ MAY TEMPORARILY KEEP LOWERED FLIGHT
CRITERIA IN PLACE. UNSETTLED CONDITIONS WILL REMAIN OVER THE
REGION THROUGH THE NEXT 24 HOURS. MOUNTAIN OBSCURATIONS AND
LOWERED FLIGHT CRITERIA REMAIN IN THE PICTURE THROUGH AT LEAST
MONDAY AFTERNOON.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...WINTER STORM WARNING UNTIL 5 PM MST SUNDAY FOR COZ018-019.
UT...WINTER STORM WARNING UNTIL 5 PM MST SUNDAY FOR UTZ028.
WINTER WEATHER ADVISORY UNTIL 11 AM MST SUNDAY FOR UTZ029.
&&
$$
UPDATE...PF
SHORT TERM...JAM
LONG TERM...JAM/CC
AVIATION...15
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
852 AM MST SAT NOV 23 2013
.UPDATE...
ISSUED AT 852 AM MST SAT NOV 23 2013
COMPLEX SCENARIO THIS MORNING AND PRECIPITATION TYPE IS DETERMINED
BY THE POSITIONING OF SHALLOW COLD FRONT. HEAVY WET SNOW HAS
TAPERED OFF OVER EAST CENTRAL UTAH INTO WEST CENTRAL COLORADO. BUT
THE COLDER AIR NEVER REACHED THE SRN VALLEYS WITH RAIN AT DURANGO
AND MIXED RAIN/SNOW AT PAGOSA SPRINGS. ELECTED TO CANCEL THE
WEATHER WEATHER ADVISORY OR WINTER STORM WARNING FOR THE SRN
VALLEYS. HEAVY SNOW IS STILL POSSIBLE FOR THE SWRN COLORADO
VALLEYS...BUT NOT DURING THE NEXT SEVERAL HOURS.
PROMINENT CLOSED UPPER LOW OVER SRN CALIFORNIA WILL CONTINUE TO
SEND MOISTURE ACROSS THE REGION THROUGH SUNDAY. MOIST CONVEYOR
BELT IS NOTED OVER ARIZONA INTO SRN UTAH AND THIS ACTIVITY WILL
SLOWLY SHIFT EAST. PRECIPITATION TYPE REMAINS A CHALLENGE AND WILL
NEED TO MAKE AN ASSESSMENT...BUT ANY SNOW THAT FALLS WILL BE
CLOSER ALIGNED AS "SIERRA CEMENT" RATHER THAN THE TYPICAL POWDERY
FLUFF THAT WESTERN COLORADO TYPICALLY RECEIVES. FOR THE I70
CORRIDOR WHERE HEAVY WET SNOW FELL...CURRENT GUIDANCE SUGGEST THAT
THE COLDER SURFACE TEMPS WILL MODERATE AND THAT SNOW WILL CHANGE
OVER TO RAIN. NOT FULLY CONFIDENT WITH THIS SOLUTION BUT SEEMS
REASONABLE IF DEW POINTS CLIMB INTO THE MID 30S. LOTS OF FORECAST
QUESTIONS TODAY AS THIS WINTER STORM CONTINUES TO EVOLVE.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 438 AM MST SAT NOV 23 2013
UPPER LEVEL LOW CONTINUES TO PUMP MOISTURE INTO OUR REGION...OVERRUNNING
COLD AIR AT THE SURFACE AND PRODUCING HEAVY WET SNOW. EXPECTING
TEMPS TO STAY SOMEWHAT HINDERED TODAY...AS CLOUD COVER WITH
INTERMITTENT BANDS OF SNOW CONTINUES AND NOW A COLD SNOW-COVERED
SURFACE IS PRESENT IN MANY AREAS. MANY NORMALLY ARID AREAS
RECEIVED NOTABLE AMOUNTS OF SNOW OVERNIGHT INCLUDING OVER 5 INCHES
JUST SOUTH OF MOAB AND OVER 3 INCHES AT GRAND JUNCTION AS OF
MIDNIGHT WITH LIGHT TO MODERATE SNOW CONTINUING SINCE. THAT BEING
SAID...SNOW LEVELS IN THE SOUTHERN CWA HAVE NOT REACHED VALLEY
FLOORS...KEEPING BOTH CORTEZ AND DURANGO IN RAIN INSTEAD OF
CHANGING OVER TO SNOW. NOT EXPECTING THIS TO CHANGE
TODAY...ESPECIALLY WITH WARM AIR CONTINUING TO PUMP UP INTO THE
REGION AT MID LEVELS.
CURRENT RADAR SHOWS BAND OF MODERATE SNOW FROM MOAB NORTHEAST TO
EAGLE. TRICKY ADVISORY/WARNING EVENTS THIS WEEKEND...AS SNOW IS
COMING IN WAVES. KEPT ADVISORIES OUT FOR THE GRAND VALLEY AND I-70
CORRIDOR TO EDWARDS UNTIL 11AM AS THE SNOW CONTINUES TO COME DOWN
IN LIGHT TO MODERATE RATES. CAN ALREADY SEE MORE LIGHT ECHOES
ON RADAR MOVING INTO THE NORTHERN SAN JUANS MTNS. FAVORING A
BLEND OF THE RAP AND NAM12 IN THE SHORT TERM AS THE RAP IS
IDENTIFYING SMALLER SCALE FEATURES BUT THE NAM IS BETTER ON
TIMING. THAT BEING SAID...THE BEST CHANCE OF SNOWFALL BY LATE
MORNING TODAY WILL BE DOWN IN THE FOUR CORNERS AREA. THIS
PRECIPITATION WILL GRADUALLY MOVE NORTHEAST THROUGHOUT THE
AFTERNOON AND IS EXPECTED TO REACH THE GRAND VALLEY AND I-70
CORRIDOR AGAIN BY THIS EVENING. DECIDED TO NOT PUT OUT ANY NEW
ADVISORIES AT THIS POINT SINCE SNOWFALL AMTS LOOK TO BE LESS THAN
THIS ONGOING FRI NIGHT/SAT MORNING EVENT...BUT DEFINITELY
SOMETHING THAT WE WILL BE KEEPING AN EYE ON. THE UPPER LEVEL JET
MOVES EAST TONIGHT...WHICH WILL BE ONE LESS FACTOR TO HELP
SMPLIFY THE SNOWFALL RATES TODAY. DYNAMICAL LIFTING AHEAD OF THE
LOW PRESSURE REMAINS DECENT FOR CONTINUATION OF SNOW PRODUCTION
THROUGH A WELL-SATURATED ENVIRONMENT.
THE FUN CONTINUES THROUGH SUNDAY AS THE UPPER LEVEL LOW FINALLY
ACCELERATES EAST OVER THE FOUR CORNERS BY SUNDAY EVENING. AS THE
LOW PROCEEDS EAST... WRAPAROUND MOISTURE AIDED BY DISTURBANCES
WITHIN THE SYSTEM WILL CONTINUE UNTIL THE ENTIRETY IS OUT OF THE
REGION FOR THE EARLY WORKWEEK.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 438 AM MST SAT NOV 23 2013
SHOULD NOTICE A DIMINISH IN PRECIPITATION BY SUNDAY NIGHT IN ALL
AREAS BUT THE CENTRAL TO EASTERN SAN JUAN MTNS UP INTO THE
GUNNISON VALLEY WHICH WILL LIKELY CONTINUE THROUGH MONDAY MORNING.
MONDAY THROUGH FRIDAY...ON MONDAY THE LOW CENTER WILL HAVE MOVED
TO NE NM AND INTO THE TX/OK PANHANDLES. NORTH TO NORTHEAST FLOW
ALOFT WILL SPREAD ACROSS THE AREA AND PCPN WILL BE CONFINED TO THE
CO SW MTS AND THE CONTINENTAL DIVIDE IN THE NORTHERN AND CENTRAL
CO MTS. CLEARING SKIES AND DRYING CONDITIONS WILL SPREAD EAST FROM
EASTERN UT. A SHARP RIDGE WILL BUILD OVER THE GREAT BASIN MON NIGHT
AND MOVE EAST...WITH THE UPPER RIDGELINE PASSING OVER EASTERN UT
AND WESTERN CO ON WED. THURSDAY AND FRIDAY THE PATTERN TRANSITIONS
FROM THE DOMINANT RIDGE OVER THE WEST TO THE NEXT BIG PACIFIC
TROUGH...WHICH THE MIDRANGE MODELS MOVE ONSHORE OVER NORTHERN
CALIFORNIA ON FRIDAY. SW WINDS ALOFT WILL INCREASE OVER THE
FORECAST AREA FRIDAY WITH INCREASING CLOUDS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 438 AM MST SAT NOV 23 2013
A SIGNIFICANT WINTER STORM WILL CONTINUE TO PRODUCE WIDESPREAD
MVFR CIGS AND VSBYS ACROSS WESTERN CO AND EASTERN UT THROUGH
SUNDAY. PERIODS OF IFR...AND BRIEF LIFR...ARE EXPECTED AT KEGE...
KRIL...KTEX...KGJT...KDRO...KCEZ...AND KPSO. THE MOUNTAINS AND
HIGH MOUNTAIN PASSES WILL BE FREQUENTLY OBSCURED.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...WINTER STORM WARNING UNTIL 5 PM MST SUNDAY FOR COZ018-019.
UT...WINTER STORM WARNING UNTIL 5 PM MST SUNDAY FOR UTZ028.
WINTER WEATHER ADVISORY UNTIL 11 AM MST SUNDAY FOR UTZ029.
&&
$$
UPDATE...PF
SHORT TERM...JAM
LONG TERM...JAM/CC
AVIATION...CC
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
440 AM MST SAT NOV 23 2013
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 438 AM MST SAT NOV 23 2013
UPPER LEVEL LOW CONTINUES TO PUMP MOISTURE INTO OUR REGION...OVERRUNNING
COLD AIR AT THE SURFACE AND PRODUCING HEAVY WET SNOW. EXPECTING
TEMPS TO STAY SOMEWHAT HINDERED TODAY...AS CLOUD COVER WITH
INTERMITTENT BANDS OF SNOW CONTINUES AND NOW A COLD SNOW-COVERED
SURFACE IS PRESENT IN MANY AREAS. MANY NORMALLY ARID AREAS
RECEIVED NOTABLE AMOUNTS OF SNOW OVERNIGHT INCLUDING OVER 5 INCHES
JUST SOUTH OF MOAB AND OVER 3 INCHES AT GRAND JUNCTION AS OF
MIDNIGHT WITH LIGHT TO MODERATE SNOW CONTINUING SINCE. THAT BEING
SAID...SNOW LEVELS IN THE SOUTHERN CWA HAVE NOT REACHED VALLEY
FLOORS...KEEPING BOTH CORTEZ AND DURANGO IN RAIN INSTEAD OF
CHANGING OVER TO SNOW. NOT EXPECTING THIS TO CHANGE
TODAY...ESPECIALLY WITH WARM AIR CONTINUING TO PUMP UP INTO THE
REGION AT MID LEVELS.
CURRENT RADAR SHOWS BAND OF MODERATE SNOW FROM MOAB NORTHEAST TO
EAGLE. TRICKY ADVISORY/WARNING EVENTS THIS WEEKEND...AS SNOW IS
COMING IN WAVES. KEPT ADVISORIES OUT FOR THE GRAND VALLEY AND I-70
CORRIDOR TO EDWARDS UNTIL 11AM AS THE SNOW CONTINUES TO COME DOWN
IN LIGHT TO MODERATE RATES. CAN ALREADY SEE MORE LIGHT ECHOES
ON RADAR MOVING INTO THE NORTHERN SAN JUANS MTNS. FAVORING A
BLEND OF THE RAP AND NAM12 IN THE SHORT TERM AS THE RAP IS
IDENTIFYING SMALLER SCALE FEATURES BUT THE NAM IS BETTER ON
TIMING. THAT BEING SAID...THE BEST CHANCE OF SNOWFALL BY LATE
MORNING TODAY WILL BE DOWN IN THE FOUR CORNERS AREA. THIS
PRECIPITATION WILL GRADUALLY MOVE NORTHEAST THROUGHOUT THE
AFTERNOON AND IS EXPECTED TO REACH THE GRAND VALLEY AND I-70
CORRIDOR AGAIN BY THIS EVENING. DECIDED TO NOT PUT OUT ANY NEW
ADVISORIES AT THIS POINT SINCE SNOWFALL AMTS LOOK TO BE LESS THAN
THIS ONGOING FRI NIGHT/SAT MORNING EVENT...BUT DEFINITELY
SOMETHING THAT WE WILL BE KEEPING AN EYE ON. THE UPPER LEVEL JET
MOVES EAST TONIGHT...WHICH WILL BE ONE LESS FACTOR TO HELP
SMPLIFY THE SNOWFALL RATES TODAY. DYNAMICAL LIFTING AHEAD OF THE
LOW PRESSURE REMAINS DECENT FOR CONTINUATION OF SNOW PRODUCTION
THROUGH A WELL-SATURATED ENVIRONMENT.
THE FUN CONTINUES THROUGH SUNDAY AS THE UPPER LEVEL LOW FINALLY
ACCELERATES EAST OVER THE FOUR CORNERS BY SUNDAY EVENING. AS THE
LOW PROCEEDS EAST... WRAPAROUND MOISTURE AIDED BY DISTURBANCES
WITHIN THE SYSTEM WILL CONTINUE UNTIL THE ENTIRETY IS OUT OF THE
REGION FOR THE EARLY WORKWEEK.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 438 AM MST SAT NOV 23 2013
SHOULD NOTICE A DIMINISH IN PRECIPITATION BY SUNDAY NIGHT IN ALL
AREAS BUT THE CENTRAL TO EASTERN SAN JUAN MTNS UP INTO THE
GUNNISON VALLEY WHICH WILL LIKELY CONTINUE THROUGH MONDAY MORNING.
MONDAY THROUGH FRIDAY...ON MONDAY THE LOW CENTER WILL HAVE MOVED
TO NE NM AND INTO THE TX/OK PANHANDLES. NORTH TO NORTHEAST FLOW
ALOFT WILL SPREAD ACROSS THE AREA AND PCPN WILL BE CONFINED TO THE
CO SW MTS AND THE CONTINENTAL DIVIDE IN THE NORTHERN AND CENTRAL
CO MTS. CLEARING SKIES AND DRYING CONDITIONS WILL SPREAD EAST FROM
EASTERN UT. A SHARP RIDGE WILL BUILD OVER THE GREAT BASIN MON NIGHT
AND MOVE EAST...WITH THE UPPER RIDGELINE PASSING OVER EASTERN UT
AND WESTERN CO ON WED. THURSDAY AND FRIDAY THE PATTERN TRANSITIONS
FROM THE DOMINANT RIDGE OVER THE WEST TO THE NEXT BIG PACIFIC
TROUGH...WHICH THE MIDRANGE MODELS MOVE ONSHORE OVER NORTHERN
CALIFORNIA ON FRIDAY. SW WINDS ALOFT WILL INCREASE OVER THE
FORECAST AREA FRIDAY WITH INCREASING CLOUDS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 438 AM MST SAT NOV 23 2013
A SIGNIFICANT WINTER STORM WILL CONTINUE TO PRODUCE WIDESPREAD
MVFR CIGS AND VSBYS ACROSS WESTERN CO AND EASTERN UT THROUGH
SUNDAY. PERIODS OF IFR...AND BRIEF LIFR...ARE EXPECTED AT KEGE...
KRIL...KTEX...KGJT...KDRO...KCEZ...AND KPSO. THE MOUNTAINS AND
HIGH MOUNTAIN PASSES WILL BE FREQUENTLY OBSCURED.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...WINTER STORM WARNING UNTIL 5 PM MST SUNDAY FOR COZ018-019.
WINTER WEATHER ADVISORY UNTIL 11 AM MST THIS MORNING FOR COZ007-
008.
WINTER WEATHER ADVISORY UNTIL 11 AM MST SUNDAY FOR COZ022.
WINTER WEATHER ADVISORY UNTIL 8 AM MST THIS MORNING FOR COZ006.
WINTER STORM WARNING UNTIL 11 AM MST SUNDAY FOR COZ023.
UT...WINTER STORM WARNING UNTIL 5 PM MST SUNDAY FOR UTZ028.
WINTER WEATHER ADVISORY UNTIL 11 AM MST SUNDAY FOR UTZ022-029.
WINTER WEATHER ADVISORY UNTIL 8 AM MST THIS MORNING FOR UTZ027.
&&
$$
SHORT TERM...JAM
LONG TERM...JAM/CC
AVIATION...CC
AREA FORECAST DISCUSSION
NWS ALBANY NY
1242 PM EST SAT NOV 23 2013
.SYNOPSIS...
AN ARCTIC COLD FRONT WILL PLUNGE SOUTH THROUGH THE REGION THIS
AFTERNOON...AND TRIGGER LAKE EFFECT SNOW DOWNWIND OF THE EASTERN
GREAT LAKES...WITH SNOW SHOWERS AND SQUALLS IN MANY OTHER PARTS
OF THE REGION. HIGH PRESSURE WILL BUILD EAST FROM THE GREAT
PLAINS TONIGHT AND SLIDE OFFSHORE BY MONDAY...BRINGING WINDY AND
WINTER LIKE VERY COLD CONDITIONS. LATE MONDAY A WARM FRONT WILL
PUSH THROUGH THE REGION. ANOTHER WEAK COLD FRONT WILL FOLLOW ON
TUESDAY...AS A STORM EJECTS NORTHWARD ALONG THE ATLANTIC SEABOARD.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
CURRENT OBSERVATIONS AND TRENDS ARE CONSISTENT WITH CURRENT
FORECAST. SO...PREVIOUS DISCUSSION STILL DESCRIBES THE FACTORS IN
THE FORECAST THROUGH THIS AFTERNOON.
PREV AFD BELOW...
THE ENTIRE AREA IS STILL PRECIP- FREE LATE THIS MORNING...AS
SHORT- WAVE RIDGING STILL IN CONTROL. HOWEVER...LAKE ENHANCED SNOW
STARTING TO DEVELOP ACROSS THE EASTERN LAKE ONTARIO COUNTIES AND
THE TUG HILL AHEAD OF AN ARCTIC BOUNDARY...WHICH IS ALLOWING
WESTERLY FLOW TO ALIGN WITH FURTHER COOLING ALOFT. HIGH RES MODELS
SUCH AS THE HRRR AND LOCAL WRF INDICATE BANDS OF LAKE ENHANCED
SNOW SHOWERS AND SQUALLS WILL DEVELOP EARLY THIS AFTERNOON ACROSS
THE WESTERN ADIRONDACKS...AND PUSH SOUTH AND EAST ALONG THE ARCTIC
FRONT LATER THIS AFTERNOON INTO THE EARLY EVENING. BEST
ACCUMULATIONS STILL LOOK TO BE ACROSS HERKIMER COUNTY...WHERE MORE
LAKE MOISTURE AND UPSLOPE COMPONENT WILL ENHANCE
SNOWFALL...ALTHOUGH A QUICK INCH OR TWO OF ACCUMULATION WILL BE
POSSIBLE ESPECIALLY FROM THE MOHAWK VALLEY NORTHWARD INTO THE
ADIRONDACKS. SCATTERED SNOW SHOWERS AND EVEN A FEW SQUALLS MAY
MAKE IT INTO THE CAPITAL REGION AND EASTERN CATSKILLS AROUND 4-6
PM. RAISED POPS IN THESE AREAS TO ACCOUNT FOR THIS POSSIBLE
ACTIVITY ALONG THE ARCTIC BOUNDARY.
AS THE ARCTIC FRONT MOVES THROUGH THE FLOW BEHIND IT WILL QUICKLY
TURN TO A 310 TO 320 ORIENTATION SO THE LAKE ENHANCED SNOW SHOWERS
AND SQUALLS WILL NOT LAST THAT LONG OVER NORTHERN HERKIMER COUNTY
AND HAVE LIMITED THE ACCUMULATIONS TO 3 TO 6 INCHES THROUGH THIS
EVENING. SNOW SQUALLS WILL LIKELY AFFECT AT LEAST PARTS OF THE
MOHAWK AND SCHOHARIE VALLEYS...AND THE EASTERN CATSKILLS AFTER THE
FLOW BECOMES 310 TO 320 DEGREES...BUT THIS IS NOT LIKELY TO OCCUR
UNTIL THIS EVENING.
TEMPS WILL NOT RISE VERY MUCH FROM THE MORNING LOWS DUE TO THE COLD
ADVECTION THAT WILL BE OCCURRING. HIGHS TODAY WILL BE BETWEEN THE
UPPER 20S AND 40 FOR MOST OF THE FORECAST AREA...WITH LOW OR MID 40S
OVER THE MID HUDSON VALLEY AND NORTHWEST CT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/...
ITS WINTER...FOR REAL AS TEMPS WILL RUN 10-20F BLO NORMALS NEXT
FEW DAYS. GUID SUITE GFS/NAM/GEM IN FAIRLY GOOD AGREEMENT DURING
MOST OF THIS PERIOD. 500HPA TROF AXIS SWINGS THROUGH REGION THIS
EVNG...ARCTIC CDFNT SURGES SOUTH THROUGH REST OF RGN...AND FRIGID
AIR FOR NOV POURS IN. CDFNT WILL TRIGGER SNOW SQUALLS AND -SHSN WITH
ITS PASSAGE THIS EVENING...THEN EVENT EVOLVES INTO LK EFFECT/NW-N
FLOW TRRN EVENT. LK EFFECT FOCUS QUICKLY SHIFTS W OF FCA BASED ON
NAM/LOCAL WRF DURING LATE EVNG HOURS. REST OF NIGHT UPSLOPE -SHSN
OVER GREENS...ADIRONDACKS AND CATSKILLS. BY SUNDAY CAP SETS UP OVER
LK ONT AT 4KFT BASED ON BUFKIT. THIS SHOULD DIMINISH ANY LK
EFFECT...AND FLOW IS SUCH IT WILL BE WEST OF FCA...AND NOT PENETRATE
VERY FAR INLAND WITHOUT HELP FROM TRRN OR OTHER LAKES.
WIND GRADIENT BECOMES VERY STRONG AT 12-14 MB ACRS NYS TNGT AND
SUN. BY SUNDAY MORNING FLOW IS PARALLEL UP TO 500 HPA. STRONG WINDS
WILL BUFFET THE REGION WITH NAM/GFS BDNRY LAYER WINDS 25-35
KTS...AND MET/MAV GUID WINDS 15-25MPH. WIND ADVISORIES MAY NEED TO
BE CONSIDERED FOR TNGT AND SUN. AWAY FM E GRTLKS SKIES WILL BCM PS
SUNDAY...BUT ANY SUN WILL HARDLY BE NOTICEABLE.
WINDS COMBINED WITH TEMPS IN SINGLE DIGITS TO TEENS...ONLY RISING
TO TEENS TO MID 20S SUNDAY WILL RESULT IN WIND CHILLS JUST ABV
ADVISORY VALUES. IT WILL BE QUITE A MAJOR CHANGE FM PAST FEW
WEEKS.
SUN NT THE MAIN 500HPA TROF AXIS SHIFTS EAST OF FCA AND LARGE SFC
HIGH SLIDES FM OH VLY TO DELMARVA WITH RIDGE N INTO QB. WINDS
WILL GRADUALLY DIMINISH AS RIDGE CRESTS OVR RGN BY DAYBREAK. WITH
CLEAR SKIES...SNOW COVER IN MANY PLACES N & W OF ALB...LONG NIGHT
AND WINDS BCMG LT AND VRBL...TEMPS WILL PLUNGE TO SINGLE DIGITS
TO TEENS WITH LOWS BELOW ZERO IN SOME PARTS OF ADIRONDACKS.
MONDAY SFC HIGH SLIDES OFFSHORE AND WMFNT PUSHES THRU RGN. MOST
OF THE GUID BRINGS INCRG CLOUDS...BUT LITTLE QPF. GIVEN THE
MAGNITUDE OF THE CD AIR THAT`S HERE...AND RESIDUAL LK
EFFECT...WILL CONSIDER KEEPING CHC -SHSN. MON NT A WK CDFNT AND
500HPA TROF PASS ACROSS RGN. THE GFS/GEM TRIGGERS ANOTHER ROUND OF
SCT -SHSN...AGAIN MAINLY N & W WHERE SOME LK ENHANCEMENT WILL
ASSIST....THE NAM MAINLY DRY.
BY TUES ALL GUID HAS A CDFNT DROPPING SE INTO THE GRTLKS AS 500HPA
CUTOFF DIGS INTO GRTLKS. MDLS BY TUES HAVE SOME SPREAD...BUT WERE
CONVERGING ON A SOLUTION....EVEN THOUGH THEY HAVE MADE A
SIGNIFICANT SHIFT FM MOST OF FRI GUID. GEM/ECMWF/HPC WEAKLY PHASE
THE N AND S STREAM 500HPA TROFS OVER THE EAST ON TUES...WITH EAST
COASTAL STORM DEEPENING AND MOVING NE THROUGH GA/CAROLINA PIEDMONT
BEFORE MOVING JUST OFFSHORE AND NORTHWARD TO LONG ISLAND NY.
OPERATIONAL GFS TAKES THIS SYSTEM OUT TO SEA LARGELY S OF FCA..AND
IS NOW AN OUTLIER...EVEN TO ITS OWN ENSEMBLE...WHICH IS COALESCING
AROUND A FEW CAMPS...QPF OF EITHER 0.1...1.0 AND 1.5 INCHES LIQ.
MOST MEMBERS START WITH AND INCH OR TWO OF SNOW CHANGE MOSTLY TO
RAIN. 4 OR 5 ARE STILL MOSTLY SNOW...BUT ONLY ONE OF THE 1.0 QPF
MEMBERS IS ALL SNOW. MOST HAVE A QPF OF 1-1.5 INCHES LIQ.
LATE TUES MIX PCPN WILL OVERSPREAD RGN FM S TO N...CHANGING
QUICKLY TO RAIN.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
COASTAL STORM IS OFF NJ COAST WED MORNING....500HPA TROF SWINGS
OFFSHORE...AS DOES STORM...WITH PCPN ENDING FM W TO E DURING THE
MORNING. ANOTHER ARCTIC HIGH BUILDS TWRD RGN FM ONT/QB WED NT INTO
THANKSGIVING. WINDS WILL BE BRISK AGAIN DURING THIS PERIOD AND
TEMPS WELL BLO NORMAL. WITH N-NW FLOW LK RESPONSE WILL BE LIMITED
AND WELL WEST OF AREA. SOME SCT UPSLOPE -SHSN WILL BE AROUND.
THE WEEK WILL END WITH LARGE SFC HIGH PRESSURE OVER EASTERN PARTS
OF NATION...BUT SIGNIFICANT 500HPA TROF OVER NE AND E GRTLKS. THIS
TROF WILL LIKELY ENHANCE LK EFFECT RESPONSE...MAINLY W OF
FCA...BUT SOME -SHSN OVER W REACHES OF FCA. MOST OF REGN WILL BE
COLD AND DRY. TEMPS WILL BE WELL BLO NORMAL AND MORE TYPICAL OF
JANUARY. WILL POPULATE WITH HPC MIDNIGHT GRIDS.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
AN ARCTIC COLD FRONT WILL APPROACH FROM THE THE NORTHWEST THIS
AFTERNOON...CROSSING THE TERMINALS BETWEEN AROUND 21Z AND 00Z.
SCATTERED SNOW SHOWERS AND EVEN A FEW SNOW SQUALLS ARE POSSIBLE
ASSOCIATED WITH THE PASSAGE OF THE FRONT. WILL MENTION A TEMPO
GROUP AT KALB/KPSF/KGFL TO ACCOUNT FOR THE SNOW SHOWERS...BUT WILL
ONLY EXPLICITLY MENTION MVFR CONDITIONS FOR NOW SINCE ANY IFR/LIFR
EXPECTED TO BE BRIEF. LESS OF A CHANCE OF MEASURABLE SNOW AT
KPOU...SO ONLY MENTIONED VCSH THERE. A FEW ADDITIONAL SNOW SHOWERS
ARE POSSIBLE BEHIND THE FRONT TONIGHT...BEFORE SHIFTING WELL SOUTH
AND WEST OF THE AREA BY SUNDAY MORNING. MAINLY VFR CONDITIONS ARE
EXPECTED EXPECT IN SNOW SHOWERS.
GUSTY NORTHWEST WINDS WILL BE ANOTHER CONCERN THROUGH THE
PERIOD...WITH SUSTAINED SPEEDS AROUND 12-19 KT WITH GUSTS OF 25 TO
NEAR 35 KT POSSIBLE...ESPECIALLY ON SUNDAY.
OUTLOOK...
SUNDAY: MODERATE OPERATIONAL IMPACT. WINDY.
SUNDAY NIGHT: LOW OPERATIONAL IMPACT.BREEZY NO SIG WX.
MONDAY: NO OPERATIONAL IMPACT. NO SIG WX.
MONDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHSN.
TUESDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF RA...SN.
TUESDAY NIGHT: HIGH OPERATIONAL IMPACT. RA/SN LIKELY.
WEDNESDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF RA...SN.
&&
.HYDROLOGY...
NO HYDRO PROBLEMS ARE EXPECTED THROUGH THE NEXT 5 DAYS.
A SERIES OF COLD FRONTS WILL BRING LIGHT PRECIPITATION TO THE AREA
OVER THE WEEKEND. HEAVIEST LIQUID EQUIVALENT PRECIPITATION WILL BE
OVER THE WESTERN ADIRONDACKS AND WESTERN MOHAWK VALLEY WHERE 0.10
TO 0.33 INCHES MAY FALL...MAINLY AS SNOW. LITTLE RIVER RESPONSE IS
EXPECTED. MAINLY DRY AND WEATHER IS EXPECTED FOR MONDAY AND
TUESDAY.
THE FRIGID AIR MASS ON SUNDAY WILL ALLOW ICE TO BEGIN TO FORM ON
SHALLOWER LAKES AND RIVERS SUNDAY INTO EARLY NEXT WEEK.
TUESDAY INTO WEDNESDAY A COASTAL STORM COULD BRING 1 TO 2 INCHES
OF RAIN TO MUCH OF THE REGION...RESULTING IN SIGNIFICANT WITHIN
BANK RISES.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...LAKE EFFECT SNOW ADVISORY UNTIL 10 PM EST THIS EVENING FOR
NYZ032.
LAKE EFFECT SNOW ADVISORY FROM 6 PM THIS EVENING TO 6 AM EST
SUNDAY FOR NYZ038.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...SNYDER
NEAR TERM...GJM/NAS/JPV
SHORT TERM...SNYDER
LONG TERM...SNYDER
AVIATION...JPV
HYDROLOGY...SNYDER/NAS
AREA FORECAST DISCUSSION
NWS ALBANY NY
1237 PM EST SAT NOV 23 2013
.SYNOPSIS...
AN ARCTIC COLD FRONT WILL PLUNGE SOUTH THROUGH THE REGION THIS
AFTERNOON...AND TRIGGER LAKE EFFECT SNOW DOWNWIND OF THE EASTERN
GREAT LAKES...WITH SNOW SHOWERS AND SQUALLS IN MANY OTHER PARTS
OF THE REGION. HIGH PRESSURE WILL BUILD EAST FROM THE GREAT
PLAINS TONIGHT AND SLIDE OFFSHORE BY MONDAY...BRINGING WINDY AND
WINTER LIKE VERY COLD CONDITIONS. LATE MONDAY A WARM FRONT WILL
PUSH THROUGH THE REGION. ANOTHER WEAK COLD FRONT WILL FOLLOW ON
TUESDAY...AS A STORM EJECTS NORTHWARD ALONG THE ATLANTIC SEABOARD.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 1023 AM...THE ENTIRE AREA IS STILL PRECIP-FREE LATE THIS
MORNING...AS SHORT-WAVE RIDGING STILL IN CONTROL. HOWEVER...LAKE
ENHANCED SNOW STARTING TO DEVELOP ACROSS THE EASTERN LAKE ONTARIO
COUNTIES AND THE TUG HILL AHEAD OF AN ARCTIC BOUNDARY...WHICH IS
ALLOWING WESTERLY FLOW TO ALIGN WITH FURTHER COOLING ALOFT. HIGH
RES MODELS SUCH AS THE HRRR AND LOCAL WRF INDICATE BANDS OF LAKE
ENHANCED SNOW SHOWERS AND SQUALLS WILL DEVELOP EARLY THIS
AFTERNOON ACROSS THE WESTERN ADIRONDACKS...AND PUSH SOUTH AND EAST
ALONG THE ARCTIC FRONT LATER THIS AFTERNOON INTO THE EARLY
EVENING. BEST ACCUMULATIONS STILL LOOK TO BE ACROSS HERKIMER
COUNTY...WHERE MORE LAKE MOISTURE AND UPSLOPE COMPONENT WILL
ENHANCE SNOWFALL...ALTHOUGH A QUICK INCH OR TWO OF ACCUMULATION
WILL BE POSSIBLE ESPECIALLY FROM THE MOHAWK VALLEY NORTHWARD INTO
THE ADIRONDACKS. SCATTERED SNOW SHOWERS AND EVEN A FEW SQUALLS MAY
MAKE IT INTO THE CAPITAL REGION AND EASTERN CATSKILLS AROUND 4-6
PM. RAISED POPS IN THESE AREAS TO ACCOUNT FOR THIS POSSIBLE
ACTIVITY ALONG THE ARCTIC BOUNDARY.
AS THE ARCTIC FRONT MOVES THROUGH THE FLOW BEHIND IT WILL QUICKLY
TURN TO A 310 TO 320 ORIENTATION SO THE LAKE ENHANCED SNOW SHOWERS
AND SQUALLS WILL NOT LAST THAT LONG OVER NORTHERN HERKIMER COUNTY
AND HAVE LIMITED THE ACCUMULATIONS TO 3 TO 6 INCHES THROUGH THIS
EVENING. SNOW SQUALLS WILL LIKELY AFFECT AT LEAST PARTS OF THE
MOHAWK AND SCHOHARIE VALLEYS...AND THE EASTERN CATSKILLS AFTER THE
FLOW BECOMES 310 TO 320 DEGREES...BUT THIS IS NOT LIKELY TO OCCUR
UNTIL THIS EVENING.
TEMPS WILL NOT RISE VERY MUCH FROM THE MORNING LOWS DUE TO THE COLD
ADVECTION THAT WILL BE OCCURRING. HIGHS TODAY WILL BE BETWEEN THE
UPPER 20S AND 40 FOR MOST OF THE FORECAST AREA...WITH LOW OR MID 40S
OVER THE MID HUDSON VALLEY AND NORTHWEST CT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/...
ITS WINTER...FOR REAL AS TEMPS WILL RUN 10-20F BLO NORMALS NEXT
FEW DAYS. GUID SUITE GFS/NAM/GEM IN FAIRLY GOOD AGREEMENT DURING
MOST OF THIS PERIOD. 500HPA TROF AXIS SWINGS THROUGH REGION THIS
EVNG...ARCTIC CDFNT SURGES SOUTH THROUGH REST OF RGN...AND FRIGID
AIR FOR NOV POURS IN. CDFNT WILL TRIGGER SNOW SQUALLS AND -SHSN WITH
ITS PASSAGE THIS EVENING...THEN EVENT EVOLVES INTO LK EFFECT/NW-N
FLOW TRRN EVENT. LK EFFECT FOCUS QUICKLY SHIFTS W OF FCA BASED ON
NAM/LOCAL WRF DURING LATE EVNG HOURS. REST OF NIGHT UPSLOPE -SHSN
OVER GREENS...ADIRONDACKS AND CATSKILLS. BY SUNDAY CAP SETS UP OVER
LK ONT AT 4KFT BASED ON BUFKIT. THIS SHOULD DIMINISH ANY LK
EFFECT...AND FLOW IS SUCH IT WILL BE WEST OF FCA...AND NOT PENETRATE
VERY FAR INLAND WITHOUT HELP FROM TRRN OR OTHER LAKES.
WIND GRADIENT BECOMES VERY STRONG AT 12-14 MB ACRS NYS TNGT AND
SUN. BY SUNDAY MORNING FLOW IS PARALLEL UP TO 500 HPA. STRONG WINDS
WILL BUFFET THE REGION WITH NAM/GFS BDNRY LAYER WINDS 25-35
KTS...AND MET/MAV GUID WINDS 15-25MPH. WIND ADVISORIES MAY NEED TO
BE CONSIDERED FOR TNGT AND SUN. AWAY FM E GRTLKS SKIES WILL BCM PS
SUNDAY...BUT ANY SUN WILL HARDLY BE NOTICEABLE.
WINDS COMBINED WITH TEMPS IN SINGLE DIGITS TO TEENS...ONLY RISING
TO TEENS TO MID 20S SUNDAY WILL RESULT IN WIND CHILLS JUST ABV
ADVISORY VALUES. IT WILL BE QUITE A MAJOR CHANGE FM PAST FEW
WEEKS.
SUN NT THE MAIN 500HPA TROF AXIS SHIFTS EAST OF FCA AND LARGE SFC
HIGH SLIDES FM OH VLY TO DELMARVA WITH RIDGE N INTO QB. WINDS
WILL GRADUALLY DIMINISH AS RIDGE CRESTS OVR RGN BY DAYBREAK. WITH
CLEAR SKIES...SNOW COVER IN MANY PLACES N & W OF ALB...LONG NIGHT
AND WINDS BCMG LT AND VRBL...TEMPS WILL PLUNGE TO SINGLE DIGITS
TO TEENS WITH LOWS BELOW ZERO IN SOME PARTS OF ADIRONDACKS.
MONDAY SFC HIGH SLIDES OFFSHORE AND WMFNT PUSHES THRU RGN. MOST
OF THE GUID BRINGS INCRG CLOUDS...BUT LITTLE QPF. GIVEN THE
MAGNITUDE OF THE CD AIR THAT`S HERE...AND RESIDUAL LK
EFFECT...WILL CONSIDER KEEPING CHC -SHSN. MON NT A WK CDFNT AND
500HPA TROF PASS ACROSS RGN. THE GFS/GEM TRIGGERS ANOTHER ROUND OF
SCT -SHSN...AGAIN MAINLY N & W WHERE SOME LK ENHANCEMENT WILL
ASSIST....THE NAM MAINLY DRY.
BY TUES ALL GUID HAS A CDFNT DROPPING SE INTO THE GRTLKS AS 500HPA
CUTOFF DIGS INTO GRTLKS. MDLS BY TUES HAVE SOME SPREAD...BUT WERE
CONVERGING ON A SOLUTION....EVEN THOUGH THEY HAVE MADE A
SIGNIFICANT SHIFT FM MOST OF FRI GUID. GEM/ECMWF/HPC WEAKLY PHASE
THE N AND S STREAM 500HPA TROFS OVER THE EAST ON TUES...WITH EAST
COASTAL STORM DEEPENING AND MOVING NE THROUGH GA/CAROLINA PIEDMONT
BEFORE MOVING JUST OFFSHORE AND NORTHWARD TO LONG ISLAND NY.
OPERATIONAL GFS TAKES THIS SYSTEM OUT TO SEA LARGELY S OF FCA..AND
IS NOW AN OUTLIER...EVEN TO ITS OWN ENSEMBLE...WHICH IS COALESCING
AROUND A FEW CAMPS...QPF OF EITHER 0.1...1.0 AND 1.5 INCHES LIQ.
MOST MEMBERS START WITH AND INCH OR TWO OF SNOW CHANGE MOSTLY TO
RAIN. 4 OR 5 ARE STILL MOSTLY SNOW...BUT ONLY ONE OF THE 1.0 QPF
MEMBERS IS ALL SNOW. MOST HAVE A QPF OF 1-1.5 INCHES LIQ.
LATE TUES MIX PCPN WILL OVERSPREAD RGN FM S TO N...CHANGING
QUICKLY TO RAIN.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
COASTAL STORM IS OFF NJ COAST WED MORNING....500HPA TROF SWINGS
OFFSHORE...AS DOES STORM...WITH PCPN ENDING FM W TO E DURING THE
MORNING. ANOTHER ARCTIC HIGH BUILDS TWRD RGN FM ONT/QB WED NT INTO
THANKSGIVING. WINDS WILL BE BRISK AGAIN DURING THIS PERIOD AND
TEMPS WELL BLO NORMAL. WITH N-NW FLOW LK RESPONSE WILL BE LIMITED
AND WELL WEST OF AREA. SOME SCT UPSLOPE -SHSN WILL BE AROUND.
THE WEEK WILL END WITH LARGE SFC HIGH PRESSURE OVER EASTERN PARTS
OF NATION...BUT SIGNIFICANT 500HPA TROF OVER NE AND E GRTLKS. THIS
TROF WILL LIKELY ENHANCE LK EFFECT RESPONSE...MAINLY W OF
FCA...BUT SOME -SHSN OVER W REACHES OF FCA. MOST OF REGN WILL BE
COLD AND DRY. TEMPS WILL BE WELL BLO NORMAL AND MORE TYPICAL OF
JANUARY. WILL POPULATE WITH HPC MIDNIGHT GRIDS.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
AN ARCTIC COLD FRONT WILL APPROACH FROM THE THE NORTHWEST THIS
AFTERNOON...CROSSING THE TERMINALS BETWEEN AROUND 21Z AND 00Z.
SCATTERED SNOW SHOWERS AND EVEN A FEW SNOW SQUALLS ARE POSSIBLE
ASSOCIATED WITH THE PASSAGE OF THE FRONT. WILL MENTION A TEMPO
GROUP AT KALB/KPSF/KGFL TO ACCOUNT FOR THE SNOW SHOWERS...BUT WILL
ONLY EXPLICITLY MENTION MVFR CONDITIONS FOR NOW SINCE ANY IFR/LIFR
EXPECTED TO BE BRIEF. LESS OF A CHANCE OF MEASURABLE SNOW AT
KPOU...SO ONLY MENTIONED VCSH THERE. A FEW ADDITIONAL SNOW SHOWERS
ARE POSSIBLE BEHIND THE FRONT TONIGHT...BEFORE SHIFTING WELL SOUTH
AND WEST OF THE AREA BY SUNDAY MORNING. MAINLY VFR CONDITIONS ARE
EXPECTED EXPECT IN SNOW SHOWERS.
GUSTY NORTHWEST WINDS WILL BE ANOTHER CONCERN THROUGH THE
PERIOD...WITH SUSTAINED SPEEDS AROUND 12-19 KT WITH GUSTS OF 25 TO
NEAR 35 KT POSSIBLE...ESPECIALLY ON SUNDAY.
OUTLOOK...
SUNDAY: MODERATE OPERATIONAL IMPACT. WINDY.
SUNDAY NIGHT: LOW OPERATIONAL IMPACT.BREEZY NO SIG WX.
MONDAY: NO OPERATIONAL IMPACT. NO SIG WX.
MONDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHSN.
TUESDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF RA...SN.
TUESDAY NIGHT: HIGH OPERATIONAL IMPACT. RA/SN LIKELY.
WEDNESDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF RA...SN.
&&
.HYDROLOGY...
NO HYDRO PROBLEMS ARE EXPECTED THROUGH THE NEXT 5 DAYS.
A SERIES OF COLD FRONTS WILL BRING LIGHT PRECIPITATION TO THE AREA
OVER THE WEEKEND. HEAVIEST LIQUID EQUIVALENT PRECIPITATION WILL BE
OVER THE WESTERN ADIRONDACKS AND WESTERN MOHAWK VALLEY WHERE 0.10
TO 0.33 INCHES MAY FALL...MAINLY AS SNOW. LITTLE RIVER RESPONSE IS
EXPECTED. MAINLY DRY AND WEATHER IS EXPECTED FOR MONDAY AND
TUESDAY.
THE FRIGID AIR MASS ON SUNDAY WILL ALLOW ICE TO BEGIN TO FORM ON
SHALLOWER LAKES AND RIVERS SUNDAY INTO EARLY NEXT WEEK.
TUESDAY INTO WEDNESDAY A COASTAL STORM COULD BRING 1 TO 2 INCHES
OF RAIN TO MUCH OF THE REGION...RESULTING IN SIGNIFICANT WITHIN
BANK RISES.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...LAKE EFFECT SNOW ADVISORY UNTIL 10 PM EST THIS EVENING FOR
NYZ032.
LAKE EFFECT SNOW ADVISORY FROM 6 PM THIS EVENING TO 6 AM EST
SUNDAY FOR NYZ038.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...SNYDER
NEAR TERM...GJM/JPV
SHORT TERM...SNYDER
LONG TERM...SNYDER
AVIATION...JPV
HYDROLOGY...SNYDER/NAS
AREA FORECAST DISCUSSION
NWS ALBANY NY
1023 AM EST SAT NOV 23 2013
.SYNOPSIS...
AN ARCTIC COLD FRONT WILL PLUNGE SOUTH THROUGH THE REGION THIS
AFTERNOON...AND TRIGGER LAKE EFFECT SNOW DOWNWIND OF THE EASTERN
GREAT LAKES...WITH SNOW SHOWERS AND SQUALLS IN MANY OTHER PARTS
OF THE REGION. HIGH PRESSURE WILL BUILD EAST FROM THE GREAT
PLAINS TONIGHT AND SLIDE OFFSHORE BY MONDAY...BRINGING WINDY AND
WINTER LIKE VERY COLD CONDITIONS. LATE MONDAY A WARM FRONT WILL
PUSH THROUGH THE REGION. ANOTHER WEAK COLD FRONT WILL FOLLOW ON
TUESDAY...AS A STORM EJECTS NORTHWARD ALONG THE ATLANTIC SEABOARD.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 1023 AM...THE ENTIRE AREA IS STILL PRECIP-FREE LATE THIS
MORNING...AS SHORT-WAVE RIDGING STILL IN CONTROL. HOWEVER...LAKE
ENHANCED SNOW STARTING TO DEVELOP ACROSS THE EASTERN LAKE ONTARIO
COUNTIES AND THE TUG HILL AHEAD OF AN ARCTIC BOUNDARY...WHICH IS
ALLOWING WESTERLY FLOW TO ALIGN WITH FURTHER COOLING ALOFT. HIGH
RES MODELS SUCH AS THE HRRR AND LOCAL WRF INDICATE BANDS OF LAKE
ENHANCED SNOW SHOWERS AND SQUALLS WILL DEVELOP EARLY THIS
AFTERNOON ACROSS THE WESTERN ADIRONDACKS...AND PUSH SOUTH AND EAST
ALONG THE ARCTIC FRONT LATER THIS AFTERNOON INTO THE EARLY
EVENING. BEST ACCUMULATIONS STILL LOOK TO BE ACROSS HERKIMER
COUNTY...WHERE MORE LAKE MOISTURE AND UPSLOPE COMPONENT WILL
ENHANCE SNOWFALL...ALTHOUGH A QUICK INCH OR TWO OF ACCUMULATION
WILL BE POSSIBLE ESPECIALLY FROM THE MOHAWK VALLEY NORTHWARD INTO
THE ADIRONDACKS. SCATTERED SNOW SHOWERS AND EVEN A FEW SQUALLS MAY
MAKE IT INTO THE CAPITAL REGION AND EASTERN CATSKILLS AROUND 4-6
PM. RAISED POPS IN THESE AREAS TO ACCOUNT FOR THIS POSSIBLE
ACTIVITY ALONG THE ARCTIC BOUNDARY.
AS THE ARCTIC FRONT MOVES THROUGH THE FLOW BEHIND IT WILL QUICKLY
TURN TO A 310 TO 320 ORIENTATION SO THE LAKE ENHANCED SNOW SHOWERS
AND SQUALLS WILL NOT LAST THAT LONG OVER NORTHERN HERKIMER COUNTY
AND HAVE LIMITED THE ACCUMULATIONS TO 3 TO 6 INCHES THROUGH THIS
EVENING. SNOW SQUALLS WILL LIKELY AFFECT AT LEAST PARTS OF THE
MOHAWK AND SCHOHARIE VALLEYS...AND THE EASTERN CATSKILLS AFTER THE
FLOW BECOMES 310 TO 320 DEGREES...BUT THIS IS NOT LIKELY TO OCCUR
UNTIL THIS EVENING.
TEMPS WILL NOT RISE VERY MUCH FROM THE MORNING LOWS DUE TO THE COLD
ADVECTION THAT WILL BE OCCURRING. HIGHS TODAY WILL BE BETWEEN THE
UPPER 20S AND 40 FOR MOST OF THE FORECAST AREA...WITH LOW OR MID 40S
OVER THE MID HUDSON VALLEY AND NORTHWEST CT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/...
ITS WINTER...FOR REAL AS TEMPS WILL RUN 10-20F BLO NORMALS NEXT
FEW DAYS. GUID SUITE GFS/NAM/GEM IN FAIRLY GOOD AGREEMENT DURING
MOST OF THIS PERIOD. 500HPA TROF AXIS SWINGS THROUGH REGION THIS
EVNG...ARCTIC CDFNT SURGES SOUTH THROUGH REST OF RGN...AND FRIGID
AIR FOR NOV POURS IN. CDFNT WILL TRIGGER SNOW SQUALLS AND -SHSN WITH
ITS PASSAGE THIS EVENING...THEN EVENT EVOLVES INTO LK EFFECT/NW-N
FLOW TRRN EVENT. LK EFFECT FOCUS QUICKLY SHIFTS W OF FCA BASED ON
NAM/LOCAL WRF DURING LATE EVNG HOURS. REST OF NIGHT UPSLOPE -SHSN
OVER GREENS...ADIRONDACKS AND CATSKILLS. BY SUNDAY CAP SETS UP OVER
LK ONT AT 4KFT BASED ON BUFKIT. THIS SHOULD DIMINISH ANY LK
EFFECT...AND FLOW IS SUCH IT WILL BE WEST OF FCA...AND NOT PENETRATE
VERY FAR INLAND WITHOUT HELP FROM TRRN OR OTHER LAKES.
WIND GRADIENT BECOMES VERY STRONG AT 12-14 MB ACRS NYS TNGT AND
SUN. BY SUNDAY MORNING FLOW IS PARALLEL UP TO 500 HPA. STRONG WINDS
WILL BUFFET THE REGION WITH NAM/GFS BDNRY LAYER WINDS 25-35
KTS...AND MET/MAV GUID WINDS 15-25MPH. WIND ADVISORIES MAY NEED TO
BE CONSIDERED FOR TNGT AND SUN. AWAY FM E GRTLKS SKIES WILL BCM PS
SUNDAY...BUT ANY SUN WILL HARDLY BE NOTICEABLE.
WINDS COMBINED WITH TEMPS IN SINGLE DIGITS TO TEENS...ONLY RISING
TO TEENS TO MID 20S SUNDAY WILL RESULT IN WIND CHILLS JUST ABV
ADVISORY VALUES. IT WILL BE QUITE A MAJOR CHANGE FM PAST FEW
WEEKS.
SUN NT THE MAIN 500HPA TROF AXIS SHIFTS EAST OF FCA AND LARGE SFC
HIGH SLIDES FM OH VLY TO DELMARVA WITH RIDGE N INTO QB. WINDS
WILL GRADUALLY DIMINISH AS RIDGE CRESTS OVR RGN BY DAYBREAK. WITH
CLEAR SKIES...SNOW COVER IN MANY PLACES N & W OF ALB...LONG NIGHT
AND WINDS BCMG LT AND VRBL...TEMPS WILL PLUNGE TO SINGLE DIGITS
TO TEENS WITH LOWS BELOW ZERO IN SOME PARTS OF ADIRONDACKS.
MONDAY SFC HIGH SLIDES OFFSHORE AND WMFNT PUSHES THRU RGN. MOST
OF THE GUID BRINGS INCRG CLOUDS...BUT LITTLE QPF. GIVEN THE
MAGNITUDE OF THE CD AIR THAT`S HERE...AND RESIDUAL LK
EFFECT...WILL CONSIDER KEEPING CHC -SHSN. MON NT A WK CDFNT AND
500HPA TROF PASS ACROSS RGN. THE GFS/GEM TRIGGERS ANOTHER ROUND OF
SCT -SHSN...AGAIN MAINLY N & W WHERE SOME LK ENHANCEMENT WILL
ASSIST....THE NAM MAINLY DRY.
BY TUES ALL GUID HAS A CDFNT DROPPING SE INTO THE GRTLKS AS 500HPA
CUTOFF DIGS INTO GRTLKS. MDLS BY TUES HAVE SOME SPREAD...BUT WERE
CONVERGING ON A SOLUTION....EVEN THOUGH THEY HAVE MADE A
SIGNIFICANT SHIFT FM MOST OF FRI GUID. GEM/ECMWF/HPC WEAKLY PHASE
THE N AND S STREAM 500HPA TROFS OVER THE EAST ON TUES...WITH EAST
COASTAL STORM DEEPENING AND MOVING NE THROUGH GA/CAROLINA PIEDMONT
BEFORE MOVING JUST OFFSHORE AND NORTHWARD TO LONG ISLAND NY.
OPERATIONAL GFS TAKES THIS SYSTEM OUT TO SEA LARGELY S OF FCA..AND
IS NOW AN OUTLIER...EVEN TO ITS OWN ENSEMBLE...WHICH IS COALESCING
AROUND A FEW CAMPS...QPF OF EITHER 0.1...1.0 AND 1.5 INCHES LIQ.
MOST MEMBERS START WITH AND INCH OR TWO OF SNOW CHANGE MOSTLY TO
RAIN. 4 OR 5 ARE STILL MOSTLY SNOW...BUT ONLY ONE OF THE 1.0 QPF
MEMBERS IS ALL SNOW. MOST HAVE A QPF OF 1-1.5 INCHES LIQ.
LATE TUES MIX PCPN WILL OVERSPREAD RGN FM S TO N...CHANGING
QUICKLY TO RAIN.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
COASTAL STORM IS OFF NJ COAST WED MORNING....500HPA TROF SWINGS
OFFSHORE...AS DOES STORM...WITH PCPN ENDING FM W TO E DURING THE
MORNING. ANOTHER ARCTIC HIGH BUILDS TWRD RGN FM ONT/QB WED NT INTO
THANKSGIVING. WINDS WILL BE BRISK AGAIN DURING THIS PERIOD AND
TEMPS WELL BLO NORMAL. WITH N-NW FLOW LK RESPONSE WILL BE LIMITED
AND WELL WEST OF AREA. SOME SCT UPSLOPE -SHSN WILL BE AROUND.
THE WEEK WILL END WITH LARGE SFC HIGH PRESSURE OVER EASTERN PARTS
OF NATION...BUT SIGNIFICANT 500HPA TROF OVER NE AND E GRTLKS. THIS
TROF WILL LIKELY ENHANCE LK EFFECT RESPONSE...MAINLY W OF
FCA...BUT SOME -SHSN OVER W REACHES OF FCA. MOST OF REGN WILL BE
COLD AND DRY. TEMPS WILL BE WELL BLO NORMAL AND MORE TYPICAL OF
JANUARY. WILL POPULATE WITH HPC MIDNIGHT GRIDS.
&&
.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
MAINLY VFR CONDITIONS EXPECTED AT THE KGFL/KALB/KPSF TAF SITES TODAY
WITH NO PCPN FCST. OCCASIONAL MVFR CONDITIONS WILL STILL OCCUR AT
KGFL/KALB/KPSF UNTIL AROUND 15Z. WESTERLY SURFACE WINDS WILL BLOW AT
12 TO 15 KTS WITH GUSTS OF 20 TO 25 KTS.
LATE IN THE DAY AN ARCTIC COLD FRONT WILL MOVE THROUGH AND MAY BE
ACCOMPANIED BY SCATTERED SNOW SHOWERS AND POSSIBLY HEAVIER SNOW
SQUALLS AT THE TAF SITES...ESP AFTER 22Z/SAT. THIS COULD BRING
VSBY/CIG REDUCTIONS INTO THE IFR/LIFR RANGE...ESP AT KGFL/KALB AND
KPSF WELL INTO THE EVENING. FOR NOW HAVE ONLY INDICATED VCSH IN THE
TAF FORECASTS FOR KGFL/KALB/KPSF. SURFACE WINDS WILL PICK UP EVEN
MORE AFTER THE FRONTAL PASSAGE WITH GUSTS UP TO AROUND 30 KTS
POSSIBLE...ESPECIALLY AT KALB/KPSF.
OUTLOOK...
SUNDAY: MODERATE OPERATIONAL IMPACT. WINDY.
SUNDAY NIGHT: LOW OPERATIONAL IMPACT.BREEZY NO SIG WX.
MONDAY: NO OPERATIONAL IMPACT. NO SIG WX.
MONDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHSN.
TUESDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF RA...SN.
TUESDAY NIGHT: HIGH OPERATIONAL IMPACT. RA/SN LIKELY.
WEDNESDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF RA...SN.
&&
.HYDROLOGY...
NO HYDRO PROBLEMS ARE EXPECTED THROUGH THE NEXT 5 DAYS.
A SERIES OF COLD FRONTS WILL BRING LIGHT PRECIPITATION TO THE AREA
OVER THE WEEKEND. HEAVIEST LIQUID EQUIVALENT PRECIPITATION WILL BE
OVER THE WESTERN ADIRONDACKS AND WESTERN MOHAWK VALLEY WHERE 0.10
TO 0.33 INCHES MAY FALL...MAINLY AS SNOW. LITTLE RIVER RESPONSE IS
EXPECTED. MAINLY DRY AND WEATHER IS EXPECTED FOR MONDAY AND
TUESDAY.
THE FRIGID AIR MASS ON SUNDAY WILL ALLOW ICE TO BEGIN TO FORM ON
SHALLOWER LAKES AND RIVERS SUNDAY INTO EARLY NEXT WEEK.
TUESDAY INTO WEDNESDAY A COASTAL STORM COULD BRING 1 TO 2 INCHES
OF RAIN TO MUCH OF THE REGION...RESULTING IN SIGNIFICANT WITHIN
BANK RISES.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...LAKE EFFECT SNOW ADVISORY UNTIL 10 PM EST THIS EVENING FOR
NYZ032.
LAKE EFFECT SNOW ADVISORY FROM 6 PM THIS EVENING TO 6 AM EST
SUNDAY FOR NYZ038.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...SNYDER
NEAR TERM...GJM/JPV
SHORT TERM...SNYDER
LONG TERM...SNYDER
AVIATION...GJM
HYDROLOGY...SNYDER/NAS
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
935 PM EST SUN NOV 24 2013
.SYNOPSIS...
A STRONG CANADIAN HIGH PRESSURE SYSTEM CONTINUES TO MOVE THROUGH THE
REGION AND OFFSHORE TOMORROW. A GULF OF MEXICO LOW PRESSURE SYSTEM
WILL DEVELOP AND TRACK NORTHEAST AND INTENSIFY PASSING OVER OR JUST
EAST OF THE FORECAST AREA ON WEDNESDAY. ANOTHER CANADIAN HIGH
PRESSURE SYSTEM WILL START BUILDING EAST ON THANKSGIVING DAY AND
REACH THE EASTERN SEABOARD ON THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
RED FLAG WARNING EXPIRED AT 600 PM AS WINDS DIMINISHED AFTER
SUNSET.
WINDS DIMINISHED SHARPLY AFTER SUNSET, AND WIND GRIDS WERE
UPDATED WITH HRRR DATA WHICH BEST REFLECTED THE RAPID CHANGE. USED
LAV FORE TEMPERATURE DEW POINT GRIDS FOR NEXT 4 HOURS. OVERNIGHT
MINIMUMS LOOK ON TRACK (AND VERY COLD) AND WERE LEFT UNCHANGED.
OVERNIGHT LOWS WILL DROP INTO THE TEENS IN MANY LOCALES. SOME
RECORDS FOR NOVEMBER 25TH COULD BE CHALLENGED.
WE`LL CALL FOR MAINLY CLEAR SKIES. WE COULD SEE SOME MID- AND
HIGH- LEVEL CLOUDS ENTER THE PICTURE TOWARD DAWN, BUT THEY SHOULD
BE THIN.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH 6 PM MONDAY/...
SURFACE HIGH PRESSURE WILL SHIFT OFF THE COAST TOMORROW AFTERNOON.
WINDS WILL RESPOND AND GO SOUTHWEST. SPEEDS WILL TOP OUT IN THE 10
TO 15 MPH RANGE.
DOESN`T LOOK LIKE WE`LL SEE MUCH CU TOMORROW, SO WE`LL JUST BRING
SOME MID-LEVEL CLOUDINESS INTO THE PICTURE.
HIGH WILL TOP OUT IN THE UPPER 20S NORTH AND WEST TO THE UPPER 30S
ELSEWHERE.
&&
.LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
WE START OFF THE LONGTERM PERIOD FAIRLY TRANQUIL BUT QUICKLY RAMP UP
TO SOMETHING RATHER SPECTACULAR LATE TUESDAY NIGHT...POTENTIAL
NOR`EASTER BEARING DOWN ON THE REGION. BETTER AGREEMENT TODAY IN
REGARDS THE SYSTEM MOVING UP THE EASTERN SEABOARD ON TUESDAY NIGHT INTO
WEDNESDAY. A MAJORITY OF THE 00Z GUIDANCE YESTERDAY MOVED THE TRACK
FURTHER TO THE WEST AND THE CURRENT 12Z MAINTAINS THAT TRACKING.
THIS WOULD ULTIMATELY BRING THE THE SYSTEM INLAND AND MOVE IT
THROUGH PARTS OF SOUTHERN NEW JERSEY, POSSIBLY AS FAR NORTH AS ALONG
THE I-95 CORRIDOR. THE ENSEMBLE GUIDANCE FOR THE MOST PART SUPPORTS
A SYSTEM HUGGING THE COAST OR SLIGHTLY INLAND, BUT THEY ALSO SHOW
VERY ANOMALOUS PWAT AIR ADVECTING IN TOO.
IT CAN NOT BE STATED ENOUGH THAT THE PTYPE FROM THIS SYSTEM IS
HIGHLY DEPENDENT ON EXACT TRACK OF THE SYSTEM. FOR THE TIME BEING,
AND AS STATED ABOVE, WE ARE LOOKING AT A SYSTEM THAT IS MOVING OVER
PORTIONS OF OUR INTERIOR CWA. THIS SETS UP A VERY SHARP TEMPERATURE
AND QPF GRADIENT. AN INITIAL SHOT OF PRECIPITATION SHOULD START
TUESDAY AFTERNOON AS THE TWO SHORTWAVES BEGIN TO PHASE TO DRAW UP
THE GOMEX MOISTURE. AT THIS POINT OUR NORTHWEST ZONES SHOULD BE
COLD ENOUGH TO SEE A LIGHT SNOWFALL WITH VERY LIGHT ACCUMULATIONS
POSSIBLE THOUGH DRY AIR IN PLACE MAY NOT PERMIT MUCH OF IT REACH
THE GROUND. TEMPERATURES SHOULD BEGIN TO RISE UNDER A
STRENGTHENING LLJ FROM THE SOUTH-SOUTHEAST AND AREAS OUTSIDE OF
THE HIGHER TERRAIN SHOULD SEE A TRANSITION OVER TO PLAIN RAIN BY
THE LATE AFTERNOON HOURS. THIS IS WHERE THINGS BECOME A BIT MORE
TRICKY.
THE WARMER, MOISTER AIR, WILL SWEEP THROUGH THE REGION BY TUESDAY
NIGHT CHANGING EVERYTHING OVER TO A LIQUID. SURFACE TEMPERATURES
MAY LAG WARMING ABOVE FREEZING FOR A COUPLE OF HOURS ACROSS THE
NORTHERN ZONES THUS LEADING TO FREEZING RAIN ACCUMULATIONS POSSIBLE
THROUGH EARLY WEDNESDAY MORNING. ELSEWHERE, MODERATE TO HEAVY RAIN
CAN BE EXPECTED ACROSS A BETTER PORTION OF THE REGION. WPC HAS PLACE
A MAJORITY OF THE REGION IN A SLIGHT RISK FOR EXCESSIVE RAINFALL ON
WEDNESDAY...AMOUNTS UP TO 3 INCHES ARE POSSIBLE IN SPOTS WITH DECENT
FRONTOGENETIC BANDING TAKING PLACE.
THE ELONGATED TROUGH SUPPORTING THE LOW SLOWLY MOVES FURTHER
NORTHEAST AS DOES THE SURFACE SYSTEM AND WE START TO CLEAR THINGS
OUT FROM SOUTHWEST TO NORTHEAST. ANY REMAINING MOISTURE ACROSS THE
REGION WILL FALL AS A LIGHT SNOW AS ANOTHER SHOT OF COLD CANADIAN
AIR FILTERS BACK INTO THE REGION. HIGH PRESSURE MOVES IN ALOFT BY
THURSDAY AND FRIDAY. WE MAINLY LEFT
&&
.AVIATION /02Z MONDAY THROUGH FRIDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
TONIGHT...NO SIGNIFICANT CHANGES ON 00Z TAF ISSUANCE. VFR WITH
DIMINISHING WINDS. THE NORTHWEST GUSTY WINDS WILL SUBSIDE TO 10 KT
OR LESS AND BECOME MORE WESTERLY.
MONDAY...VFR. WEST MORNING WINDS 5 TO 10 KT BECOMING SOUTHWEST IN
THE AFTERNOON.
OUTLOOK...
TUESDAY - WEDNESDAY...DETERIORATING CONDITIONS EXPECTED AS A
COASTAL LOW PRESSURE SYSTEM PASSING BY THE REGION...FROM SOUTH TO
NORTH. MVFR TO IFR CONDITIONS ARE EXPECTED TO PREVAIL FROM LATER
TUESDAY INTO MUCH OF WEDNESDAY. THERE IS ALSO A LOW LEVEL WIND
SHEAR POTENTIAL CENTERED AROUND TUESDAY NIGHT. CONFIDENCE IS
INCREASING ABOUT A DISRUPTIVE TRAVELING IMPACT.
WEDNESDAY NIGHT...PRIMARILY MVFR WITH GUSTY NORTHWEST WINDS.
THURSDAY...VFR WITH GUSTY NORTH WINDS.
&&
.MARINE...
TONIGHT...CONTINUE TO TRIM BACK ON THE GALE WARNING AND IT NOW IS
ONLY IN EFFECT FOR MARINE ZONE 450 UNTIL 400 AM MONDAY. SMALL
CRAFT ADVISORY CONTINUES ON DELAWARE BAY UNTIL 300 AM MONDAY, AND
SMALL CRAFT ADVISORY ON THE OCEAN FOR ALL OTHER ZONES BESIDES 450
IS IN EFFECT UNTIL 400 AM MONDAY.
EXPECT WINDS TO CONTINUE TO DIMINISH STEADILY OVERNIGHT AND SEAS
TO RESPOND.
TOMORROW...THE NORTHWEST WINDS WILL BACK TO THE WEST/SOUTHWEST. BOTH
WIND SPEEDS AND SEAS SHOULD DROP BELOW ANY HEADLINE (E.G. SCA)
CRITERIA.
OUTLOOK...
MONDAY NIGHT - TUESDAY...SUB-ADVISORY WIND CONDITIONS EXPECTED.
SEAS MIGHT REACH 5 FEET ON THE OCEAN ON TUESDAY.
TUESDAY NIGHT - THURSDAY...A COASTAL LOW PRESSURE SHOULD IMPACT OUR
WATERS STARTING TUESDAY EVENING. SEAS AND WINDS WILL INCREASE TO
SMALL CRAFT CRITERIA AS THE SYSTEM PASSES BY TO THE NORTHEAST ON
WEDNESDAY INTO THURSDAY. THERE IS A CHANCE FOR GALE FORCE CONDITIONS
ON BOTH SIDES OF THE LOW.
&&
.FIRE WEATHER...
RED FLAG WARNING EXPIRED AT 600 PM AS WINDS CONTINUE TO DIMINISH
AFTER SUNSET.
&&
.CLIMATE...
RECORD LOW MAXIMUM TEMPERATURES WERE SET TODAY AT MANY LOCATIONS
IN OUR FORECAST AREA. WE HAVE POSTED THE RER`S FOR THE FOUR
HISTORICALLY LONG TERM CLIMATE SITES.... KPHL KILG KACY AND KABE.
A COMPARISON TO NORMALS WAS MADE.
ADDITIONALLY WE HAVE CHECKED AND SO...TODAYS COLD LOW MAX`S WERE
NOT THE EARLIEST ON RECORD. COLDER HIGH TEMPERATURES OCCURRED ON
NOVEMBER 16 1933 AT ALL THE ABOVE CLIMATE SITES.
MONDAYS RECORD LOWS ARE VULNERABLE AT KPHL KABE KTTN KRDG
RECORD LOWS...
ATLANTIC CITY...16 DEGREES IN 1989.
PHILADELPHIA....21 DEGREES IN 1965.
WILMINGTON......18 DEGREES IN 1970.
ALLENTOWN.......16 DEGREES IN 1989.
TRENTON.........20 DEGREES IN 2005.
GEORGETOWN......16 DEGREES IN 1970.
READING.........17 DEGREES IN 1956.
MOUNT POCONO.....6 DEGREES IN 1989.
THE LAST TIME PHILADELPHIA HAD A NOVEMBER LOW IN THE TEENS WAS 19
DEGREES IN 1989 AND THE LAST TIME PHILADELPHIA HAD A MAX TEMPERATURE
AT OR BELOW FREEZING WAS IN 1996. PHILLY WAS 31 DEGREES AT MIDNIGHT.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 AM EST MONDAY FOR ANZ451>455.
GALE WARNING UNTIL 4 AM EST MONDAY FOR ANZ450.
SMALL CRAFT ADVISORY UNTIL 3 AM EST MONDAY FOR ANZ430-431.
&&
$$
SYNOPSIS...GIGI/HEAVENER
NEAR TERM...SZATKOWSKI/KRUZDLO
SHORT TERM...KRUZDLO
LONG TERM...GIGI/HEAVENER
AVIATION...SZATKOWSKI/HEAVENER/KRUZDLO
MARINE...SZATKOWSKI/HEAVENER/KRUZDLO
FIRE WEATHER...SZATKOWSKI
CLIMATE...GIGI/STAFF
AREA FORECAST DISCUSSION
NWS MIAMI FL
1004 AM EST SAT NOV 23 2013
.UPDATE...
LATEST SURFACE ANALYSIS SHOWS WEAK FRONTAL SYSTEM APPROACHING
NORTHERN FLORIDA AT THIS TIME. THIS SYSTEM WILL NEVER REALLY MAKE
IT PASSED SOUTH FLORIDA BUT RATHER BY PASS THE REGION TO THE NORTH
TONIGHT WITH WINDS PICKING UP BEHIND IT FROM THE NORTH TOMORROW AS
DESCRIBED BELOW. AHEAD OF IT TODAY, SATELLITE IMAGERY AND SURFACE
ANALYSIS SHOW SUBTLE CONVERGENCE LINE CUTTING ACROSS THE NEAR
SHORE MIAMI DADE WATERS AND ACROSS MIAMI DADE AND COLLIER COUNTIES
BETWEEN TAMIAMI TRAIL AND ALLIGATOR ALLEY. NORTH OF THESE ROAD
LAND MARKS AREA DEW POINTS MOSTLY IN THE 60S AND SOUTH OF THEM IN
THE LOW 70S. BLENDED GPSMET/AMSU SATELLITE BASED PRODUCT ALSO
SHOWS PRECIPITABLE WATER VALUES WELL ABOVE NORMAL PARTICULARLY
ACROSS SOUTHERN SECTIONS OF CWA DESPITE THE FACT THIS MORNING
SOUNDING IS NOT AS SATURATED AS LAST THREE WERE. WHAT THIS MORNING
SNDG SHOWED SOMEWHAT BETTER THAN LAST COUPLE OF DAYS WAS STEEPER
LOW LEVEL LAPSE RATES. GIVEN THERE IS A CHANCE OF INLAND AREAS
WARMING INTO THE LOWER TO MID 80S INTO THIS AFTERNOON DESPITE
INCREASING CLOUDINESS PARAMETERS SUPPORT A SLIGHT CHANCE OF A
THUNDERSTORM.
ENSEMBLE OF LOCAL HIGH RES MODELS HINT AT THIS ACROSS AREAS SOUTH
OF ALLIGATOR ALLEY AS WE HEAD IN THE AFTERNOON AND EARLY EVENING.
HOWEVER, THE HRRR DOES NOT REFLECT THIS. GIVEN THIS, INCREASED
RAIN CHANCES A BIT TO AROUND 30% AND MENTIONED A SLIGHT CHANCE OF
A THUNDERSTORM THIS AFTERNOON PARTICULARLY ACROSS AREAS SOUTH OF
ALLIGATOR ALLEY AWAY FROM THE EAST COAST.
NO MAJOR CONCERNS WITH ANY ACTIVITY THAT MANAGES TO DEVELOP TODAY
OTHER THAN THE SLIGHT RISK OF A LIGHTNING STRIKE ACROSS THE
AFOREMENTIONED AREAS.
&&
.PREV DISCUSSION... /ISSUED 614 AM EST SAT NOV 23 2013/
AVIATION...
OUTSIDE OF A FEW SHOWERS SPREADING ASHORE ALONG THE EAST COAST
THAT HAVE THE POTENTIAL OF BRIEFLY ALTERING CIGS/VSBYS TO MVFR
LEVELS...VFR CONDITIONS WILL PREVAIL WITH LIGHT EASTERLY WINDS.
PREV DISCUSSION... /ISSUED 302 AM EST SAT NOV 23 2013/
.DRIER WEATHER FOR FIRST HALF OF THIS WEEKEND...BEFORE INCREASED
MOISTURE ALONG WITH WINDY CONDITIONS FOR SECOND HALF OF THE
WEEKEND...
SHORT TERM...
AN OLD FRONTAL BOUNDARY WILL SLOWLY DISSIPATE THROUGH TONIGHT OVER
THE FLORIDA KEYS...AS HIGH PRESSURE OVER THE MID ATLANTIC STATES MOVES
EAST INTO THE ATLANTIC WATERS. THIS WILL KEEP AN EASTERLY WIND
FLOW OVER SOUTH FLORIDA TODAY INTO TONIGHT ALONG WITH MOSTLY DRY
WEATHER. THE ONLY CHANCE OF SEEING A SHOWER OR TWO IS OVER THE
EAST COAST METRO AREAS AND THE ATLANTIC WATERS. SO WILL KEEP A
SLIGHT CHANCE OF POPS IN FOR THE EAST COAST METRO AREAS THROUGH
TONIGHT WHILE REST OF SOUTH FLORIDA REMAINS DRY.
THE HIGH WILL CONTINUE TO MOVE FURTHER EAST INTO THE ATLANTIC WATERS
ON SUNDAY...AS A STRONG COLD FRONT MOVES SOUTHWARD FROM THE SOUTHEASTERN
UNITED STATES AND THROUGH SOUTH FLORIDA. THIS WILL ALLOW FOR THE
WIND FLOW TO BACK FROM A EASTERLY DIRECTION TODAY TO A NORTHERLY
FLOW ON SUNDAY...AS THE WINDS INCREASE FROM 10 TO 15 MPH TODAY TO
WINDY CONDITIONS LATE SUNDAY. THIS FRONT WILL ALSO ALLOW SCATTERED
SHOWERS OVER THE EAST COAST METRO AREAS ON SUNDAY...WITH ISOLATED
SHOWERS ELSEWHERE OVER SOUTH FLORIDA.
THE THREAT OF RIP CURRENTS WILL ALSO CONTINUE ALONG THE EAST COAST
BEACHES OF SOUTH FLORIDA THIS WEEKEND INTO EARLY NEXT WEEK.
LONG TERM...
THE STRONG COLD FRONT WILL CONTINUE TO MOVE INTO THE FLORIDA KEYS
EARLY NEXT WEEK...AS A STRONG HIGH PRESSURE MOVES EAST FROM THE
CENTRAL UNITED STATES INTO THE MID ATLANTIC STATES. THIS WILL KEEP
THE PRESSURE GRADIENT OVER SOUTH FLORIDA TIGHT ALLOWING FOR BREEZY
TO WINDY NORTHERLY WINDS ALONG WITH ISOLATED TO SCATTERED SHOWERS.
THE STRONG HIGH PRESSURE WILL THEN MOVE EAST INTO THE ATLANTIC
WATERS MIDDLE OF NEXT WEEK...AS LOW PRESSURE DEVELOPS IN THE
NORTHERN GULF OF MEXICO AND MOVES NORTHEAST INTO THE SOUTHEASTERN
UNITED STATES. THIS SHOULD ALLOW FOR ANOTHER STRONG COLD FRONT TO
MOVE THROUGH THE AREA THROUGH THE MIDDLE OF NEXT WEEK BRINGING IN
DEEP TROPICAL MOISTURE TO THE AREA. ALTHOUGH MUCH OF THE FORCING
WILL REMAIN NORTH OF OUR AREA...THERE IS A CHANCE OF A SQUALL LINE
DEVELOPING AHEAD OF THE FRONT AS IT APPROACHES AND MOVES THROUGH
FROM WEST TO EAST. THIS FEATURE WILL NEED TO BE MONITORED OVER THE
WEEKEND AND INTO NEXT WEEK AS THIS SYSTEM EVOLVES WEST OF OUR AREA
AND CONFIDENCE IN MORE OF THE DETAILS INCREASE.
AVIATION...
OUTSIDE OF A FEW SHOWERS SPREADING ASHORE ALONG THE EAST COAST
THAT HAVE THE POTENTIAL OF BRIEFLY ALTERING CIGS/VSBYS TO MVFR
LEVELS...VFR CONDITIONS WILL PREVAIL WITH LIGHT EASTERLY WINDS.
MARINE...
THE WINDS WILL BE NORTHEAST TO EAST AT 10 TO 15 KNOTS TODAY INTO
TONIGHT...EXCEPT FOR MIAMI-DADE ATLANTIC WATERS WHERE THEY WILL
BE 15 TO 20 KNOTS THIS MORNING BEFORE DECREASING TO 10 TO 15 KNOTS
THIS AFTERNOON. THE WINDS WILL THEN BACK TO A NORTHERLY DIRECTION
AND RAPIDLY INCREASING TO NEAR GALE FORCE CONDITIONS BY SUNDAY
NIGHT. THIS WILL ALLOW FOR THE ATLANTIC SEAS TO BE 3 TO 5 FEET
TODAY INTO TONIGHT...BEFORE RAPIDLY INCREASING TO 11 TO 13 FEET BY
SUNDAY NIGHT. FOR THE GULF SIDE...THE SEAS WILL REMAIN 2 FEET OR
LESS TODAY INTO TONIGHT BEFORE RAPIDLY INCREASING TO 4 TO 6 FEET
NEAR-SHORE TO 6 TO 8 FEET OFFSHORE SUNDAY NIGHT. SO WILL HAVE A
SCA UP FOR THE ATLANTIC WATERS TODAY WITH A SCEC UP FOR REST OF
SOUTH FLORIDA WATERS.
WE WILL ALSO CONTINUE TO MONITOR THE WINDS AND SEAS FOR SUNDAY
AFTERNOON INTO SUNDAY NIGHT TO SEE IF A SCA OR EVEN A GALE WARNING
WILL BE NEEDED IN LATER FORECAST FOR ALL OF THE LOCAL WATERS.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 83 70 79 69 / 20 20 40 40
FORT LAUDERDALE 83 72 80 73 / 30 30 40 40
MIAMI 84 71 81 72 / 30 30 40 40
NAPLES 84 66 82 64 / 20 20 20 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...52/PS
AVIATION/RADAR...23/SK
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
407 PM CST SAT NOV 23 2013
.DISCUSSION...
145 PM CST
MAIN FORECAST CONCERNS CONTINUE TO BE COLD TEMPERATURES AND SOME
LIGHT LAKE EFFECT SNOW OVER MAINLY PORTER COUNTY TONIGHT INTO
SUNDAY...THEN THE POTENTIAL FOR SOME LIGHT SNOW AREA-WIDE ON MONDAY
WITH A DIGGING UPPER DISTURBANCE. COLDER THAN NORMAL WEATHER LOOKS
TO CONTINUE THROUGH THE PERIOD...THOUGH NO SUBSTANTIAL ORGANIZED
PRECIP PRODUCERS ARE NOTED IN MODEL GUIDANCE THROUGH NEXT WEEKEND.
STRONG 1048 MB HIGH PRESSURE WAS BUILDING SOUTHEAST ACROSS THE
NORTHERN PLAINS AND UPPER MIDWEST THIS AFTERNOON IN ASSOCIATION WITH
A SOLID PUSH OF COLD/DRY ARCTIC AIR. AIR TEMPS IN THE TEENS TO MID
20S AND SURFACE DEW POINTS IN THE LOWER SINGLE DIGITS CHARACTERIZE
THIS AIR MASS...POINTING TO A COLD NIGHT TONIGHT ACROSS THE FORECAST
AREA AS CLEARING SKIES AND DECREASING WINDS MAKE FOR FAVORABLE
COOLING CONDITIONS. OVERNIGHT LOWS ARE EXPECTED TO RANGE FROM THE
SINGLE DIGITS TO MID TEENS...WITH THE COOLEST READINGS ACROSS NORTH
CENTRAL IL WEST OF CHICAGO WHERE WINDS WILL DIMINISH MORE
SUBSTANTIALLY AND AWAY FROM URBAN WARMTH AND LAKE-INDUCED CLOUDS
DOWNWIND OF LAKE MICHIGAN INTO INDIANA. SOME LIGHT LAKE EFFECT SNOW
SHOWERS WERE IMPINGING UPON PARTS OF NORTHWEST AND NORTH CENTRAL
INDIANA INCLUDING PORTER COUNTY THIS AFTERNOON...AND THIS IS
EXPECTED TO CONTINUE TONIGHT WITH NEARLY UNIDIRECTIONAL WINDS FROM
ABOUT 330 DEGREES THROUGH THE DEEP LAKE-INDUCED MIXED LAYER. WINDS
WILL BACK MORE WESTERLY DURING THE DAY SUNDAY...PUSHING ANY
LINGERING LAKE EFFECT FLURRIES OR LIGHT SNOW SHOWERS EAST OF THE
CWA. WHILE COLD AIR ALOFT (-18 C AT 850 HPA) WILL CONTINUE TO
PRODUCE LARGE LAKE-INDUCED DELTA T/S IN EXCESS OF 20 DEG AND DEEP
EQUILIBRIUM LEVELS ABOVE 10 KFT...LACK OF MOISTURE AND MULTI-BAND
ORGANIZATION WILL KEEP SNOW SHOWERS ON THE LIGHT SIDE IN PORTER
COUNTY. SOME MINOR ACCUMULATIONS LESS THAN AN INCH IS POSSIBLE IN
EXTREME NORTHEAST PORTER COUNTY TONIGHT BEFORE BANDS MOVE EAST OF
AREA SUNDAY. COLD START TO TEMPS SUNDAY AND SURFACE RIDGE MOVING
ACROSS THE AREA EXPECTED TO LIMIT TEMPS TO MID-20S MOST AREAS AGAIN
DESPITE AMPLE SUNSHINE.
THE NEXT IN A SERIES OF NORTHWEST FLOW UPPER TROUGHS IS PROGGED TO
DIG ACROSS THE UPPER MIDWEST SUNDAY/MONDAY. GUIDANCE INDICATES THE
MAIN DEEP LAYER FORCING WILL PASS LARGELY NORTH OF THE CWA MONDAY...
THOUGH 30-40 KT SOUTHWEST 850 HPA FLOW IS EXPECTED TO PRODUCE
SUFFICIENT WARM/MOIST ADVECTION AND ISENTROPIC ASCENT TO GENERATE
LIGHT SNOW ACROSS THE FORECAST AREA DURING THE DAY. SNOWFALL AMOUNTS
TO PERHAPS AN INCH OR SO APPEAR POSSIBLE AT THIS TIME...WITH THE
GREATEST AMOUNTS GENERALLY NORTH OF I-80 BASED ON QPF PLACEMENT
CLOSER TO THE BETTER DEEP LAYER FORCING TO OUR NORTH. A SECOND VORT
DIGS INTO THE TROUGH LATE MONDAY NIGHT/TUESDAY WHICH SLOWS EASTWARD
PROGRESSION OF THE UPPER TROUGH ACROSS THE REGION AND MAY PRODUCE
SOME ADDITIONAL LIGHT SNOW OR FLURRIES MONDAY NIGHT-TUESDAY. THE
UPPER TROUGH AXIS EVENTUALLY SLIDES OFF TO THE EAST TUESDAY
NIGHT/WEDNESDAY...WITH WEAK RIDGING ALOFT DEVELOPING AND PRODUCING
DRY CONDITIONS. THE EXCEPTION MAY BE ACROSS LAKE/PORTER COUNTIES IN
NORTHWEST INDIANA WHERE NORTH FLOW AHEAD OF THE APPROACHING SFC
RIDGE WILL LIKELY PRODUCE LAKE EFFECT SNOW SHOWERS TUESDAY
NIGHT/WEDNESDAY.
THE UPPER TROUGH AXIS MOVES EAST OF THE AREA FRIDAY. GUIDANCE
DEPICTS ANOTHER MID-LEVEL SHORT WAVE APPROACHING THE REGION
SATURDAY...THOUGH THE SURFACE LOW AGAIN PASSES NORTH OF THE AREA.
SOME POTENTIAL FOR A LITTLE LIGHT RAIN/SNOW OR LIGHT SNOW SATURDAY
AND SATURDAY NIGHT MAINLY ACROSS NORTHERN PARTS OF THE CWA...THOUGH
THE 12Z ECMWF APPEARS TO BE TRENDING FARTHER NORTH FOR NOW.
TEMPERATURES NEXT WEEK LOOK TO REMAIN SUBSTANTIALLY BELOW NORMAL FOR
LATE NOVEMBER...WITH LOW/MID 30S FOR HIGHS MOST DAYS AND LOWS IN THE
LOW/MID 20S. THIS IS ABOUT 10 DEGREES BELOW OUR NORMAL HIGHS FOR
THIS TIME OF YEAR.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 22Z...
* NONE
RC/IZZI
//DISCUSSION...UPDATED 18Z...
COLD FRONT PUSHING THROUGH CENTRAL IL AND STRONG HIGH PRESSURE
OVER THE NORTHERN PLAINS BUILDING SOUTHEAST TO MO BY SUNDAY
MORNING. TIGHT PRESSURE GRADIENT OVER THE WESTERN GREAT LAKES THIS
AFTERNOON WITH WINDS GENERALLY 320-350 DEGREES AND GUSTING TO 25
KT. AS THE HIGH MOVES SOUTHEAST THE PRESSURE GRADIENT WILL
GRADUALLY RELAX ALLOWING WINDS TO DIMINISH TONIGHT. AN AREA OF
MORE SOLID STRATOCU JUST BEHIND THE COLD FRONT HAS MOVED SOUTH OF
THE CHICAGO-ROCKFORD AREAS WITH ONLY SCT STRATOCU REMAINING OVER
NORTHERN IL. HOWEVER AREAS OF STRATOCU FILLING IN UPSTREAM OVER
WI. DON`T ANTICIPATE MUCH EXPANSION OF THIS CLOUD COVER AS A VERY
DRY LOW LEVEL AIRMASS IS SPREADING SOUTH. EXPECT MAINLY SCT CLOUDS
3500-4000 FT THIS AFTERNOON BUT AREAS OF BKN CLOUD
POSSIBLE...REMAINING VFR. MORE SOLID CLOUD COVER OVER NORTHERN IN
DUE TO LAKE EFFECT...WITH GYY EXPECTED TO BE MAINLY BKN AROUND
3000-4000. CLOUDS OVER NORTHERN IL SHOULD DISSIPATE AROUND OR
SHORTLY AFTER SUNSET...WHILE LAKE EFFECT CLOUDS SLOWLY SHIFT
FURTHER EAST OVER NORTH CENTRAL IN DUE TO LOW LEVEL WINDS
GRADUALLY BECOMING MORE NW.
AS THE HIGH SHIFTS EAST INTO THE OHIO VALLEY SUNDAY...WINDS WILL
TURN WEST THEN SOUTHWEST DURING THE DAY SUNDAY.
ALLSOPP
//ORD AND MDW CONFIDENCE...UPDATED 22Z...
* HIGH CONFIDENCE IN ALL ELEMENTS.
RC/IZZI
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT...VFR.
MONDAY...CHC OF SNOW AND IFR WITH LIGHT ACCUMULATION POSSIBLE.
TUESDAY...MVFR AND FLURRIES POSSIBLE IN THE MORNING.
WEDNESDAY-FRIDAY...CHC FOR LAKE EFFECT MVFR CLOUDS BUT MAINLY
VFR.
MTF
&&
.MARINE...
151 PM CST
LOW PRESSURE OVER SOUTHEAST CANADA CONTINUES TO SHIFT EAST WHILE A
STRONG CANADIAN HIGH SINKS INTO THE CENTRAL PLAINS THIS EVENING.
THE HIGH SLOWLY WEAKENS AS IT PASSES OVER THE SOUTHERN MISSISSIPPI
RIVER VALLEY TOMORROW AFTERNOON AND THEN REACHES THE CAROLINAS BY
MONDAY MORNING. NORTHWEST GALES WILL CONTINUE THROUGH THIS EVENING
BEFORE THE THE GRADIENT WEAKENS AND WINDS DIMINISH. ***SOMETHING
ABOUT THE SMALL CRAFT***
AS THE HIGH SHIFTS EAST...A LOW PRESSURE SYSTEM DROPS INTO MANITOBA
SUNDAY EVENING. THE PRESSURE GRADIENT TIGHTENS OVER THE LAKE AND
SOUTHWEST GALES ARE EXPECTED LATE SUNDAY EVENING THROUGH MONDAY
AFTERNOON. ***AS SUCH HAVE ISSUED A GALE WATCH ACROSS THE OPEN
WATERS.*** THE LOW PASSES NORTH OF THE GREAT LAKES MONDAY WITH WINDS
TURNING WEST BEHIND ITS COLD FRONT MONDAY EVENING. WINDS CONTINUE
TO VEER TO THE NORTH TUESDAY NIGHT AS HIGH PRESSURE SHIFTS
SOUTHWEST. THE HIGH/S CENTER PASSES NORTH OF THE GREAT LAKES
WEDNESDAY AFTERNOON. GUIDANCE DIFFERS ON THE PATTERN AFTER
WEDNESDAY WITH THE ECMWF INDICATING THE HIGH WILL DISSIPATE WHILE A
LOW MOVES OVER THE LAKE THURSDAY EVENING. THE GFS ON THE OTHER HAND
HAS THE HIGH SHIFTING EAST AND THE NEXT LOW STAYING WELL NORTH OF
THE LAKES AND OVER HUDSON BAY. THEREFORE FOR NOW WILL HAVE WEAK
SOUTH WINDS ON THURSDAY BECOMING NORTHWEST.
JEE
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ744-LMZ745-LMZ777-
LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 PM
SATURDAY.
GALE WATCH...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...9 PM SUNDAY TO 9 PM
MONDAY.
SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO GARY IN UNTIL 3 PM
SUNDAY.
&&
$$
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FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion
National Weather Service Lincoln IL
242 PM CST Sat Nov 23 2013
.DISCUSSION...
ISSUED 230 PM CST Sat Nov 23 2013
1050 mb Arctic high pressure centered over northeast South Dakota
early this afternoon has brought a real taste of winter weather to
the area. Clouds quickly increased along the leading edge of the
Arctic air mass late this morning to our north and that band of
clouds and flurries has quickly spread south early this afternoon.
Temperatures were not going anywhere with readings ranging from
the mid 20s north to the lower 30s far southeast. Wind chills were
the real story today with most areas in the 10 to 20 degree range
early this afternoon.
SHORT TERM...Tonight through Tuesday
Temperatures the main forecast concern this period along with
light snow chances Monday as another cold blast settles southeast
into the region.
The center of the cold air mass will edge over our area by Sunday
morning bringing very cold temperatures to the entire forecast
area with early morning lows from around 5 far northwest to the low
teens far southeast. Wind chill indices will range from 0 to 5 below.
The large high pressure system will drift off to our east by late
Sunday bringing another cold day to our area but with much lighter
winds. Return flow sets up across the west Sunday night as the high
shifts well off to our east with deeper moisture from the cutoff low
over the southern Plains and a northern stream wave and cold front
approach from the northwest.
Prefer the more consistent look to the GFS and past few runs of the
ECMWF which brings some decent isentropic lift into our area Monday
morning as pressure deficits lower suggesting we may see a period of
light snow by mid to late morning which should track east over the
remainder of the forecast area by afternoon. At this time, snowfall
looks to be quite light, less than an inch, especially across the
north. The NAM seems to be too agressive with the moisture transport
north into the colder air compared to the GFS and ECMWF with the
latest ECMWF splitting the two significant areas of lift, with one
area of forcing tracking to our north later on Monday, while the
second area of lift and moisture associated with the southwest
cutoff tracks just south of I-70.
The southwest system is expected to eject rather quickly northeast
into eastern TN by late Tuesday keeping the more significant rain
and snow just south of our area. Meanwhile, further north, another
Arctic surge is forecast to drop 850 temps down to between -12 and
-15 by late Tuesday night accompanied by rather gusty north winds
again thanks to the deepening storm system off to our southeast.
Another night with temperatures in the teens to middle 20s with
wind chills down into the single digits north to the low-mid teens
southeast.
LONG TERM...Wednesday through Saturday
Split flow pattern to prevail through the week featuring several
fast moving shortwaves in the northern stream, which will influence
our weather, while another cutoff low moves into southern California
by Friday. That feature will then move in a similar way to the current
upper low over the southwest U.S. this weekend, affecting the southern
Plains beyond this forecast period.
We will start out rather cold midweek as the next Arctic air mass
settles across the Midwest, but the upper pattern will deamplify
somewhat by the end of the week bringing in slightly warmer air to
our area by Friday and Saturday when afternoon temperatures rise
into the upper 30s to lower 40s, which is still well below normal
for this time of year. Precip-wise...little if any rain or snow
is expected this period with our only chances coming along with
the disturbances in the northern stream late in the week. However,
forcing and deeper moisture will be lacking with these systems so
will continue to go with a dry forecast through Saturday.
Smith
&&
.AVIATION...
ISSUED 1131 AM CST Sat Nov 23 2013
Large area of diurnal cloud cover has developed and spread across
central Illinois late this morning. Based on satellite timing tools
and to a lesser extent the latest HRRR data, think MVFR ceilings
will persist at the terminals until after 20/21z. Once clouds
dissipate/track further southeastward, clear skies are expected
tonight into Sunday. Strong northwesterly winds gusting to between
20 and 25kt will gradually subside to around 10kt toward sunset.
As high pressure builds into the Illinois River Valley late
tonight into Sunday morning, winds will become light/variable at
KPIA, but will remain northwesterly at around 5kt at the remaining
TAF sites.
Barnes
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1146 AM CST SAT NOV 23 2013
.DISCUSSION...
1056 AM CST
FOR MORNING UPDATE...
A COUPLE OF MINOR CHANGES TO GOING FORECAST THIS MORNING. MADE SOME
TWEAKS TO MAX/HOURLY TEMPS THROUGH THE AFTERNOON HOURS AND
MAINTAINED SOME SCATTERED FLURRIES ACROSS THE SOUTHERN CWA INTO
EARLY AFTERNOON.
ARCTIC COLD FRONT PUSHED SOUTH ACROSS THE FORECAST AREA EARLY THIS
MORNING. TEMPS HAVE REACHED HIGHS IN THE LOW-MID 20S ACROSS THE
NORTHERN HALF OR SO OF THE FORECAST AREA...WITH STRONG COLD
ADVECTION EXPECTED OFFSET ANY SUN-INDUCED WARMING. FARTHER SOUTH
TEMPS HAVE RISEN INTO THE UPPER 20S...BUT WILL LIKELY FALL A COUPLE
DEGREES THIS AFTERNOON OF DEGREES AS COLDER AIR SURGES SOUTH. AREA
OF STRATOCU ACROSS THE CENTRAL/SOUTHERN PARTS OF THE CWA HAVE BEEN
PRODUCING FLURRIES...AND WILL CONTINUE TO DO SO ACROSS THE SOUTHERN
COUNTIES INTO EARLY AFTERNOON AHEAD OF STRONG MID-LEVEL VORT
PROPAGATING SOUTHEASTWARD ACROSS THE AREA. OTHERWISE...VERY DRY LOW
LEVEL ARCTIC AIR WITH DEW POINT TEMPS IN THE SINGLE DIGITS IS
SPREADING ACROSS THE REGION AND SHOULD PRECLUDE MUCH IN THE WAY OF
ADDITIONAL DEEPER STRATOCU OR FLURRIES ONCE THE VORT DEPARTS.
OTHERWISE...PARTLY CLOUDY...WINDY AND COLD ARE THE WEATHER WORDS FOR
THE REMAINDER OF THE DAY.
THUS HAVE MADE SOME ADJUSTMENTS TO HOURLY TEMPS AND MAX TEMP GRIDS
AS OUTLINED ABOVE...AND HAVE MAINTAINED SCATTERED FLURRIES INTO THE
EARLY AFTERNOON HOURS ACROSS THE SOUTH.
RATZER
//PREV DISCUSSION...
308 AM CST
THE VERY COLD AIR IS RIGHT ON OUR DOOR STEP EARLY THIS MORNING. THE
MAIN FORECAST CONCERNS CONTINUE TO FOCUS ON THE UNSEASONABLE COLD
CONDITIONS EXPECTED ACROSS THE AREA TODAY AND ON SUNDAY.
THE ARCTIC FRONT IS CURRENTLY ENTERING FAR NORTHERN ILLINOIS AS OF
THIS WRITING...AND THIS FRONT WILL CONTINUE TO SHIFT SOUTHWARD
ACROSS THE AREA THROUGH THE EARLY MORNING HOURS TODAY. ONCE THE
FRONT PASSES...EXPECT THE WINDS TO QUICKLY INCREASE OUT OF THE
NORTHWEST. A STRONG AREA OF SURFACE HIGH PRESSURE...CURRENTLY AROUND
1050 MB ACROSS NORTHWESTERN NORTH DAKOTA...WILL BUILD SOUTHWARD DOWN
THE MISSOURI RIVER VALLEY THROUGH THE DAY TODAY. AS THIS
OCCURS...THIS WILL DEVELOP A RATHER STOUT SURFACE PRESSURE GRADIENT
ACROSS THE REGION. THIS GRADIENT WILL LIKELY SUPPORT WIND SPEEDS OF
20 TO 25 MPH WITH GUSTS UP TO 35 MPH FOR MUCH OF THE DAY. THE
COMBINATION OF THESE WINDS WITH TEMPERATURES IN THE LOW TO MID
20S...WILL RESULT IN WIND CHILLS OF 5 TO 10 ABOVE NORTH TO 10 TO 15
ABOVE SOUTH.
IN ADDITION TO THE STRONG COLD WINDS...A SHEARED MID LEVEL
DISTURBANCE...CURRENTLY NOTED IN THE WATER VAPOR IMAGERY DROPPING
SOUTHEASTWARD ACROSS SOUTHERN MN...COULD PRODUCE ENOUGH LIFT TO
RESULT IN SOME LIGHT SNOW FLURRIES THIS MORNING AS THE COLDER AIR
ARRIVES. THERE HAVE BEEN NUMEROUS REPORTS OF THIS ALREADY UPSTREAM
ACROSS WI...AND I SEE NO REASON WHY THIS WILL NOT CONTINUE SOUTHWARD
THIS MORNING. ALTHOUGH THIS WILL NOT BE MUCH OF AN IMPACT...I DID
ADD SOME ISOLATED FLURRIES IN THROUGH MID MORNING. WITH PLENTY OF
STRATOCU CU EXPECTED IN THE WAKE OF THE FRONT...I ALSO INCREASED SKY
COVER TO GO PARTLY SUNNY TO MOSTLY CLOUDY THIS MORNING...TRENDING
MORE PARTLY CLOUDY THIS AFTERNOON.
TONIGHT STILL APPEARS TO BE A VERY COLD NIGHT...ESPECIALLY ACROSS
WESTERN SECTIONS OF THE AREA. THE SURFACE HIGH IS EXPECTED TO BECOME
CENTERED ACROSS NORTHERN MISSOURI BY 12 UTC SUNDAY...WHICH WILL
LIKELY ALLOW FOR ENOUGH OF A GRADIENT TO KEEP SOME NORTHWEST WINDS
GOING ACROSS NORTHEASTERN ILLINOIS AND NORTHWESTERN INDIANA. THIS
SHOULD ALLOW FOR SLIGHTLY WARMER CONDITIONS HERE...BUT OUT WEST
ACROSS NORTH CENTRAL ILLINOIS...THE WINDS SHOULD DIMINISH SOME
OVERNIGHT...AND THIS SHOULD ALLOW TEMPS TO DROP INTO THE SINGLE
DIGITS. FARTHER EAST TOWARDS THE CHICAGO AREA...TEMPERATURES ARE
STILL EXPECTED TO DROP IN THE LOWER TO MIDDLE TEENS.
THESE VERY COLD CONDITIONS WILL SUPPORT SOME LAKE EFFECT SNOW SHOWERS
LATER TODAY AND TONIGHT. HOWEVER...WITH A NORTHWESTERLY BOUNDARY
LAYER FLOW OVER THE LAKE...MUCH OF THIS ACTIVITY WILL REMAIN TO THE
EAST OF MY AREA...WITH ONLY NORTHEASTERN PORTER COUNTY POSSIBLY
GETTING SOME LIGHTER SNOW.
THIS COLD START TO SUNDAY WILL LIKELY ONLY ALLOW TEMPS TO REBOUND
INTO THE MIDDLE TO PERHAPS UPPER 20S SUNDAY AFTERNOON. THE SURFACE
FLOW SHOULD TURN SOUTHWESTERLY SUNDAY AFTERNOON AS THE SURFACE HIGH
CONTINUES TO SHIFT SOUTHEASTWARD TOWARDS THE TENNESSEE VALLEY. WIND
SPEEDS WILL LIKELY INCREASE SUNDAY NIGHT INTO MONDAY...SO THIS
SHOULD NOT ALLOW TEMPS TO DROP OFF MUCH SUNDAY NIGHT.
A CLIPPER SYSTEM IS EXPECTED TO TRACK ACROSS SOUTHERN ONTARIO INTO
MONDAY. AS IT DOES SO...IT SHOULD SET UP SOME STIFF SOUTHWESTERLY
FLOW AS THE SURFACE GRADIENT STRENGTHENS BETWEEN THE CLIPPER AND
THE SURFACE HIGH SETTING UP ACROSS THE SOUTHEASTERN CONUS. THIS
INCREASE IN SOUTHWESTERLY FLOW APPEARS THAT IT WILL ALSO SET UP
SOME GOOD ISENTROPIC ASCENT ACROSS NORTHERN ILLINOIS ON MONDAY.
THIS COMBINED WITH A GLANCING BLOW OF SOME OF THE BETTER 500-300
MB Q-VECTOR CONVERGENCE...COMPLEMENTS OF THE UPPER DISTURBANCE
DIGGING ACROSS THE GREAT LAKES...MAY BE ENOUGH TO PRODUCE SOME
LIGHT SNOW ACROSS THE AREA ON MONDAY. OVERALL...THIS WILL NOT BE A
BIG SNOW MAKER FOR US AS IT APPEARS THAT MOISTURE WILL BE
SOMEWHAT LIMITED. ANOTHER STORM SYSTEM EXPECTED TO BE TAKING SHAPE
ACROSS THE GULF COAST REGION MAY ROB A LOT OF THE BETTER MOISTURE.
HOWEVER...THERE COULD CERTAINLY BE ENOUGH FORCING AND MOISTURE TO
RESULT IN SOME LIGHT ACCUMULATIONS ACROSS THE AREA ON MONDAY...SO
THIS WILL HAVE TO BE MONITORED. I HAVE INCREASED POPS INTO THE
HIGH END CHANCE CATEGORY...MAINLY FOR NORTHERN ILLINOIS...CLOSER
TO THE BETTER UPPER FORCING.
ANOTHER DECENT REINFORCING SHOT OF COLD AIR WILL DROP ACROSS THE
REGION BY TUESDAY AS THE CLIPPER SYSTEM DROPS ANOTHER COLD FRONT
ACROSS THE AREA. THERE IS A SLIGHT CHANCE THAT SOME FLURRIES COULD
ACCOMPANY THIS COLDER AIR INTO TUESDAY...ESPECIALLY CONSIDERING THAT
ANOTHER MID LEVEL DISTURBANCE IS EXPECTED TO QUICKLY TRANSITION
SOUTHEASTWARD ACROSS THE AREA. THIS COULD AGAIN RESULT IN ENOUGH
FORCING TO SQUEEZE OUT SOME LIGHT SNOW FLURRIES.
WITH THIS NEXT COLD PUSH...ANOTHER SURFACE HIGH WILL LIKELY SHIFT
SOUTHEAST SOMEWHERE ACROSS THE GREAT LAKES INTO MIDWEEK. THE
NORTHERLY FLOW THIS SETS UP COULD PRODUCE SOME MORE LAKE EFFECT SNOW
INTO NORTHWESTERN INDIANA BY WEDNESDAY.
TOWARDS THE END OF NEXT WEEK...THE PARADE OF CLIPPER SYSTEMS WILL
CONTINUE...WITH YET ANOTHER ONE EXPECTED TO TRANSITIONS TO OUR NORTH
BY LATE WEEK. TEMPERATURES THROUGH THE PERIOD LOOK TO CONTINUE ON
THE COLD SIDE OF NORMAL...WITH ONLY A SLOW MODERATION EXPECTED LATER
IN THE WEEK.
KJB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* NNW WINDS GUSTING TO 25 KT THIS AFTERNOON DIMINISHING OVERNIGHT.
ALLSOPP
//DISCUSSION...UPDATED 18Z...
COLD FRONT PUSHING THROUGH CENTRAL IL AND STRONG HIGH PRESSURE
OVER THE NORTHERN PLAINS BUILDING SOUTHEAST TO MO BY SUNDAY
MORNING. TIGHT PRESSURE GRADIENT OVER THE WESTERN GREAT LAKES THIS
AFTERNOON WITH WINDS GENERALLY 320-350 DEGREES AND GUSTING TO 25
KT. AS THE HIGH MOVES SOUTHEAST THE PRESSURE GRADIENT WILL
GRADUALLY RELAX ALLOWING WINDS TO DIMINISH TONIGHT. AN AREA OF
MORE SOLID STRATOCU JUST BEHIND THE COLD FRONT HAS MOVED SOUTH OF
THE CHICAGO-ROCKFORD AREAS WITH ONLY SCT STRATOCU REMAINING OVER
NORTHERN IL. HOWEVER AREAS OF STRATOCU FILLING IN UPSTREAM OVER
WI. DON`T ANTICIPATE MUCH EXPANSION OF THIS CLOUD COVER AS A VERY
DRY LOW LEVEL AIRMASS IS SPREADING SOUTH. EXPECT MAINLY SCT CLOUDS
3500-4000 FT THIS AFTERNOON BUT AREAS OF BKN CLOUD
POSSIBLE...REMAINING VFR. MORE SOLID CLOUD COVER OVER NORTHERN IN
DUE TO LAKE EFFECT...WITH GYY EXPECTED TO BE MAINLY BKN AROUND
3000-4000. CLOUDS OVER NORTHERN IL SHOULD DISSIPATE AROUND OR
SHORTLY AFTER SUNSET...WHILE LAKE EFFECT CLOUDS SLOWLY SHIFT
FURTHER EAST OVER NORTH CENTRAL IN DUE TO LOW LEVEL WINDS
GRADUALLY BECOMING MORE NW.
AS THE HIGH SHIFTS EAST INTO THE OHIO VALLEY SUNDAY...WINDS WILL
TURN WEST THEN SOUTHWEST DURING THE DAY SUNDAY.
ALLSOPP
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH CONFIDENCE IN WIND FORECAST.
* MEDIUM-HIGH CONFIDENCE IN CLOUD FORECAST. MOSTLY SCT CLOUDS BUT
COULD BE AREAS OF CIGS 3500-4000 FT THIS AFTERNOON.
ALLSOPP
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT...VFR.
MONDAY...CHC OF SNOW AND IFR WITH LIGHT ACCUMULATION POSSIBLE.
TUESDAY...MVFR AND FLURRIES POSSIBLE IN THE MORNING.
WEDNESDAY-FRIDAY...CHC FOR LAKE EFFECT MVFR CLOUDS BUT MAINLY
VFR.
MTF
&&
.MARINE...
145 AM CST
THE ACTIVE LATE AUTUMN PATTERN CONTINUES OVER THE GREAT LAKES WITH
AN ONGOING GALE TODAY FOLLOWING A COLD FRONTAL PASSAGE THAT OCCURRED
LAST NIGHT. ROBUST ARCTIC HIGH PRESSURE ACROSS THE NORTHERN PLAINS
THIS MORNING WILL BUILD SOUTHEAST AND KEEP A FAIRLY TIGHT PRESSURE
GRADIENT OVER THE LAKE. THIS WILL BE ENHANCED ONE AGAIN SUNDAY NIGHT
AS A LOW PRESSURE...OF 40 MB DIFFERENCE FROM THE HIGH
CENTER...SLIDES ACROSS THE CANADIAN PRAIRIE PROVINCES INTO ONTARIO.
WHILE IT WILL BE WARMER AIR RETURNING AHEAD OF THE LOW ON SUNDAY
NIGHT INTO EARLY MONDAY...THAT AIR WILL STILL BE FAR COOLER THAN THE
LAKE SURFACE TEMPERATURES SETTING THE STAGE FOR DEEP MIXING WITHIN
THAT PRESSURE GRADIENT. SOME GUSTS NEARING STORM FORCE ARE POSSIBLE
ACROSS THE NORTH. AN ASSOCIATED COLD FRONT WILL THEN MOVE ACROSS THE
LAKE MONDAY NIGHT AND THAT TOO MAY CONTINUE SOME GALES. USING THE
CIPS ANALOGS THERE ARE A COUPLE PAST EVENTS WITH SIMILAR LOW AND
HIGH PRESSURE PLACEMENT AS TO MONDAY MORNING...THOUGH NOT AS SHARP
OF A PRESSURE DIFFERENCE. THEY DO SHOW AT LEAST GALES ALONG THE
MICHIGAN SHORE SO GALES SHOULD BE PRETTY MUCH A DEFINITE OVER THE
OPEN WATER BY DAYBREAK MONDAY. HIGH PRESSURE THEN LOOKS TO MOVE OVER
THE LAKE BY WEDNESDAY INTO THE HOLIDAY.
MTF
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ744-LMZ745-LMZ777-
LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 PM
SATURDAY.
SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO GARY IN UNTIL 3 PM
SUNDAY.
&&
$$
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Area Forecast Discussion
National Weather Service Lincoln IL
1131 AM CST Sat Nov 23 2013
.DISCUSSION...
ISSUED 1038 AM CST Sat Nov 23 2013
Much colder airmass is flowing into central Illinois this morning
behind a departing frontal boundary. Thanks to steep low-level
lapse rates, an area of diurnal CU has rapidly developed and
expanded across north-central Illinois over the past hour. Clouds
are dropping southward and will overspread much of the KILX CWA
except the far southwest around Jacksonville through midday. Given
favorable lapse rates seen on local LAPS soundings and rapid cloud
development, would not be surprised to see a few snow flurries as
well. Have updated the forecast to better reflect current sky
trends and to add flurries. Otherwise, windy and cold weather will
be the rule. Wind gusts will reach the 25 to 30 mph range,
creating wind-chill values in the teens. Actual air temperatures
will remain nearly steady or slowly fall through the 20s during
the afternoon.
Barnes
&&
.AVIATION...
ISSUED 1131 AM CST Sat Nov 23 2013
Large area of diurnal cloud cover has developed and spread across
central Illinois late this morning. Based on satellite timing tools
and to a lesser extent the latest HRRR data, think MVFR ceilings
will persist at the terminals until after 20/21z. Once clouds
dissipate/track further southeastward, clear skies are expected
tonight into Sunday. Strong northwesterly winds gusting to between
20 and 25kt will gradually subside to around 10kt toward sunset.
As high pressure builds into the Illinois River Valley late
tonight into Sunday morning, winds will become light/variable at
KPIA, but will remain northwesterly at around 5kt at the remaining
TAF sites.
Barnes
&&
.PREV DISCUSSION...
ISSUED 320 AM CST Sat Nov 23 2013
An arctic cold front to pass through IL dry this morning. Below
normal temperatures expected across central IL through at least
Thanksgiving with upper level trofing into the eastern states.
Generally dry conditions expected expect for a chance of light
snow on Monday over mainly northern areas due to a northern stream
system moving into the Great Lakes region with yet another polar
cold front moving through Monday night.
SHORT TERM...Today through Monday night
An arctic cold front extending from weak 1020 mb low pressure over
northern Lake Huron through nw IL (approaching Rockford and the
Quad Cities), southern IA and central NE. 1050 mb arctic high
pressure was over nw ND and over se Saskatchewan and sw Manitoba.
Cirrus clouds are spreading east across central and southern IL
from the central plains ahead of this cold front. Temperatures
range from the lower 20s nw of the IL river to the lower 30s from
I-70 southeast.
Arctic cold front to pass quickly se across central and southeast
IL during this morning with brisk nw winds gusting to 20 to 30 mph
behind this front during mid or late morning and into this afternoon
as arctic high pressure pushes into western parts of MN/IA by sunset.
Temps to only rise slightly this morning into the mid 20s nw of
the IL river and near 37F at Lawrenceville before slowly falling
behind the cold front later this morning and afternoon. Partly to
mostly sunny skies expected today with cirrus clouds shifting
southward during the morning while stratocumulus clouds to affect
ne areas by midday and be more prominent over Indiana with nw flow
off warmer waters of Lake MI.
High pressure weakens a bit to 1046 mb as it moves into northern
MO by dawn Sunday clearing skies early this evening over central
IL and diminishing winds. This to bring the coldest night of the
season with lows in the upper single digits over central IL and
lower teens in southeast IL. Wind chills to get as cold as zero to
minus 5 over central IL overnight into early Sunday morning. High
pressure continues to weaken to 1038 mb as it settles into the mid
MS and OH river valleys by sunset Sunday. This to bring ample
sunday and lighter winds Sunday to central IL but staying cold
with highs in the mid to upper 20s. High pressure drifts east into
the mid Atlantic states by dawn Monday while still ridging
westward into the mid MS valley and keeping fair and cold weather
over central/se IL. Lows Sunday night in the mid to upper teens
with coldest readings in east central IL.
A northern stream short wave dives se toward the Great Lakes
region late Monday and Monday night driving a another polar cold
front se through IL. ECMWF and GFS models brings some light qpf
into central and northern IL Monday while NAM still keeping it
drier. Will add 20-40% chance of light snow to areas from I-72
north Monday. Low levels are fairly dry so this will limit snow
chances and amounts. Mostly cloudy skies Monday with highs in the
mid to upper 30s.
LONG TERM...Tuesday through Saturday
Strong 555 dm 500 mb low spining off the Southern CA coast near
San Diego to track east and develop a stronger storm system over
the southern plains Monday, into the southeast States Tuesday and
up the East Coast Wednesday, and departing the Northeast by
Thanksgiving. Extended models have been consistent on keeping this
moisture south and east of IL while reinforcing colder air into
the region for the middle of next week as 850 mb temps get as cold
as 10-14C. So below normal temperatures likely through at least
Thanksgiving. Temperatures to gradually modify next Friday and
Saturday as upper level heights and 850 mb temps rise and dry
conditions still prevail which GFS and ECWMF both agree on.
07
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
400 PM EST SAT NOV 23 2013
.SYNOPSIS...
ISSUED AT 458 AM EST SAT NOV 23 2013
A STRONG COLD FRONT WILL TRACK ACROSS THE REGION EARLY THIS MORNING
AND RESULT IN BRISK AND COLDER CONDITIONS. ALONG WITH THE COLDER AIR
WILL COME INCREASING IN LAKE EFFECT SNOW SHOWERS ACROSS FAR
NORTH CENTRAL INDIANA AND SOUTHWEST LOWER MICHIGAN THROUGH
THROUGH SUNDAY MORNING. ONLY A SLIGHT MODERATION FROM THE COLD
CONDITIONS CAN BE EXPECTED MONDAY BEFORE YET ANOTHER COLD FRONT
DROPS THROUGH THE REGION ON TUESDAY.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 400 PM EST SAT NOV 23 2013
ARCTIC AIRMASS ASSOCIATED WITH 1050MB SURFACE HIGH IS CURRENTLY
ENGULFING THE REGION...LEADING TO FALLING TEMPS AND A DECENT LAKE
RESPONSE. 850MB TEMPS CONTINUE TO FALL INTO THE UPPER TEENS BELOW
ZERO AND 700MB DELTA-T`S ARE AT OR ABOVE 30C. CERTAINLY PLENTY OF
LAKE INDUCED INSTABILITY BUT DEGREE OF UPSTREAM DRY AIR AND LOW
LEVEL FLOW TRAJECTORIES REMAIN A LIMITING FACTOR. AS PREVIOUSLY
MENTIONED...SURFACE DEWPOINTS OVER WISCONSIN ARE HOVERING AT OR
BELOW ZERO. 330 DEGREE SURFACE WINDS GIVE A DECENT FETCH ALONG LAKE
MICHIGAN BUT MOISTURE AND SENSIBLE/LATENT HEAT FLUX CAN ONLY DO SO
MUCH...ESPECIALLY GIVEN STRONG GRADIENT AND MARGINAL UPSTREAM
PRECONDITIONING FROM WESTERN LAKE SUPERIOR. THIS IS BORNE OUT BY
RELATIVELY DRY NEAR SURFACE PROFILES ON FORECAST SOUNDINGS AND
CEILINGS GENERALLY ABOVE 3 KFT DURING THE DAY TODAY. DRY AIR ALOFT
IS ALSO PREVENTING CONVECTIVE DEPTHS FROM GETTING MUCH ABOVE 7
KFT...PER NAM AND RAP FORECAST SOUNDINGS. APPEARS TO BE SOME
SEMBLANCE OF FRICTIONAL CONVERGENCE OR THERMALLY-INDUCED PRESSURE
TROUGHING ALONG THE EASTERN SHORE OF LAKE MICHIGAN BUT STRONG
NORTHWEST GRADIENT IS DISRUPTING THE FORMATION OF A SINGLE DOMINANT
BAND AND HEAVIER SNOW SHOWERS HAVE BEEN FAIRLY SPORADIC AND
DISORGANIZED THROUGHOUT THE DAY. 12Z HI-RES GUIDANCE SUGGESTS BANDS
MAY BECOME A LITTLE BETTER ORGANIZED OVERNIGHT BUT THE
AFOREMENTIONED LIMITING FACTORS WILL REMAIN LARGELY IN PLACE THROUGH
THE MORNING WITH A STIFF NORTHWEST WIND...PERSISTENT SYNOPTIC-SCALE
DRY AIR ADVECTION...AND A WELL MIXED BOUNDARY LAYER. STRONG
INSTABILITY...LONG DURATION...AND NEARLY IDEAL DGZ PLACEMENT WILL
CONTINUE TO AT LEAST PARTIALLY OFFSET THOSE NEGATIVE FACTORS THOUGH
AND WILL CONTINUE TO SEE SPURTS OF HEAVIER SNOW SHOWERS THROUGH
TOMORROW MORNING THAT COULD EVENTUALLY ADD UP TO 3-5 INCHES IN THE
ADVISORY AREA. STILL DONT EXPECT WARNING CRITERIA SNOWFALL. THE ONLY
POSSIBLE EXCEPTION MAY BE IN CASS COUNTY MI WHERE 5-8 INCHES MAY BE
POSSIBLE IF A MORE ORGANIZED/FOCUSED BAND DEVELOPS BUT CONFIDENCE IN
THIS OCCURRING IS TOO LOW TO WARRANT AN UPGRADE AT THIS POINT.
BACKING LOW LEVEL WINDS AND PERSISTENT SUBSIDENCE/DRY AIR ADVECTION
WILL BRING AN END TO LAKE AFFECT SNOW SHOWERS AROUND MIDDAY TOMORROW.
OTHER MAIN STORY DURING THIS SHORT TERM PERIOD WILL BE THE VERY COLD
TEMPERATURES. STRONG GRADIENT AND LAKE INDUCED CLOUD COVER WILL
PREVENT ANY DECOUPLING OR RADIATIVE COOLING OVERNIGHT FOR MOST OF
OUR CWA BUT VERY COLD THERMAL PROFILES ADVECTING INTO THE AREA WILL
STILL SUPPORT LOWS GENERALLY IN THE MID TEENS. COMBINED WITH THE
WIND...IT WILL FEEL LIKE THE LOW SINGLE DIGITS IN SOME AREAS. HIGHS
TOMORROW WILL STRUGGLE TO GET OUT OF THE MID 20S GIVEN 925MB TEMPS
STILL AROUND -11C. MODELS CONTINUE TO STRUGGLE WITH THE MAGNITUDE OF
THIS COLD AIRMASS AND HAVE CONTINUED TO LEAN ON THE COOLER SIDE OF
GUIDANCE.
&&
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 400 PM EST SAT NOV 23 2013
PREFERENCE THIS AFTN LIES W/SHARPER H5 EVOLUTION ALOFT MID PD IN
RESPONSE TO EWD EJECTION OF STG SRN STREAM SW UNDERNEATH AMPLIFYING
NRN STREAM ACRS THE WRN LAKES WHICH PROVIDES A PATHWAY FOR SOME XPCD
PHASING ALOFT. AS SUCH AND IN TANDEM W/GEM/NAM/EC TRENDS...BUMPED
POPS CONSIDERABLY WED-THU FOR WHAT SHLD BE A SIG LK EFFECT SNOW
EVENT AS YET ANOTHER SURGE OF COLD CANADIAN AIR FUNNELS SWD ACRS THE
LAKES.
STEEP NW FLW ALOFT CONTS THROUGH THE END OF THE PD W/PROMISE OF
CONTD WELL BLO NORMAL TEMPS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1246 PM EST SAT NOV 23 2013
ARCTIC COLD FRONT HAS NOW CLEARED BOTH TERMINALS AND VERY COLD
AIRMASS BEHIND IT HAS IGNITED NUMEROUS LAKE EFFECT SNOW SHOWERS
ACROSS THE AREA. RECENT RADAR/SURFACE OBSERVATIONS AND 12Z HI-RES
GUIDANCE SUGGEST THE STRONGEST BANDS WILL REMAIN NORTHEAST OF KSBN
BUT A FEW WEAKER BANDS COULD IMPACT THE TERMINAL THROUGH TONIGHT
WITH BRIEF IFR VISIBILITIES. KFWA COULD ALSO SEE A FEW SNOW
SHOWERS THIS AFTERNOON AND OVERNIGHT BUT IMPACT SHOULD REMAIN
LIMITED GIVEN DISTANCE FROM THE LAKE. STRONG TURBULENT MIXING AND
VERY DRY UPSTREAM AIRMASS WILL LIKELY KEEP CEILINGS IN MVFR OR
BETTER CATEGORY AT BOTH TERMINALS THROUGH THE PERIOD WITH LAKE
EFFECT SNOW TAPERING OFF LATE TOMORROW MORNING.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...LAKE EFFECT SNOW ADVISORY UNTIL 10 AM EST SUNDAY FOR INZ004>006.
MI...LAKE EFFECT SNOW ADVISORY UNTIL 10 AM EST SUNDAY FOR MIZ077>079.
OH...NONE.
LM...GALE WARNING UNTIL 10 PM EST THIS EVENING FOR LMZ043-046.
&&
$$
SYNOPSIS...MURPHY
SHORT TERM...AGD
LONG TERM...T
AVIATION...AGD
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AREA FORECAST DISCUSSION
NWS GOODLAND KS
745 PM MST SUN NOV 24 2013
.UPDATE...
ISSUED AT 734 PM MST SUN NOV 24 2013
JUST COMPLETED AN UPDATE. MODEL OUTPUT STILL PLAYING CATCHUP. FINALLY
LOOKS LIKE TONIGHT WILL HAVE STRATUS FOR MOST IF NOT ENTIRE NIGHT
ESPECIALLY EAST OF THE COLORADO BORDER. THE RUC AND GFS HAVE CAUGHT
THIS IDEA VERY WELL. COMBINED THAT WITH THE HIGHER DEWPOINTS COMING
IN WILL MAKE FOR MUCH WARMER MINS THAN CURRENTLY DEPICTED. NWP IS
WOEFULLY TOO COOL. NEW MINS BASED ON THE RUC AND ARE WARMER. ALSO
BASED ON THE RUC...INCREASED THE SKY COVER.
PER AREA 00Z SOUNDINGS AND THE RUC/NAM/GFS FORECAST SOUNDINGS DECIDED
TO ADD PATCHY FREEZING FOG AND DRIZZLE. MADE IT FOR THE ENTIRE NIGHT
BUT LOOKS LIKE THE BEST CHANCE FOR THIS LOOKS TO BE AFTER 06Z WHEN
THE WARM LAYER ALOFT BECOMES MORE ESTABLISHED. CONTINUED THE FZDZ
AND FZFG THROUGH MID MORNING IN THE EAST. ADJUSTED WIND FIELD BASED
ON LATEST RUC AND ADJUSTED DEWPOINTS UP PER LATEST GFS.
UPDATE ISSUED AT 441 PM MST SUN NOV 24 2013
UPDATED FORECAST DUE TO EXPIRED WIND ADVISORY. ALSO PER DIMINISHED
RADAR RETURNS REMOVED POPS FROM THE EASTERN PORTION OF THE FORECAST
AREA. ALSO ADJUSTED SKY COVER PER RECENT TRENDS.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 104 PM MST SUN NOV 24 2013
WATER VAPOR IMAGERY/RUC ANALYSIS INDICATED LARGE CLOSED H5 TROUGH
NEARING THE FOUR CORNERS AREA. AT THE SFC...STRONG PRESSURE
GRADIENT WAS IN PLACE ACROSS THE CWA WITH LOW DEEPENING OVER
COLORADO AND STRONG SFC RIDGE OVER EASTERN KS AND MO. NARROW AREA
OF STRONG WIND GUSTS IN EXCESS OF 40KTS...BETWEEN ITR AND GLD WAS
SLOWLY DIMINISHING.
WINDS SHOULD CONTINUE TO DECREASE AND FALL BELOW ADVISORY LEVELS
BEFORE SUNSET AS SFC COOLING ALLOWS BOUNDARY LAYER TO DECOUPLE. A
FEW LINGERING SNOW SHOWERS...WHICH LOOK LIKE THEY ARE BEING DRIVEN
BY ELEVATED CI WILL MOVE OUT OF THE AREA BY EARLY EVENING AS
POCKET OF DRY AIR SETTLES OVER THE AREA. UPPER LOW WILL NEAR THE
AREA TONIGHT AND WITH WEAK LIFT AND LOW STABILITY COULD SEE A
SHOWER OR TWO REDEVELOP AS IT PASSES. PROBABILITIES FROM ENSEMBLES
ARE VERY LOW AND GIVEN MUCH DRIER AIR MOVING INTO THE
AREA...CONFIDENCE NOT HIGH ENOUGH TO INCLUDE ATTM. WINDS WILL
DECREASE AND BECOME LIGHT TONIGHT PRIOR TO FRONTAL PASSAGE THAT
WILL BRING A PERIOD OF GUSTY NORTHERLY WINDS. WINDS ARE NOT
EXPECTED TO BE AS STRONG AS TODAY THOUGH. WITH A PERIOD OF LIGHT
WINDS AND SOME POTENTIAL THINNING OF THE HIGH CLOUDS HAVE LOWERED
MIN TEMPS SEVERAL DEGREES...ESPECIALLY ACROSS SOUTHERN CWA.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 140 PM MST SUN NOV 24 2013
THE LARGE UPPER LOW OVER THE SOUTHWESTERN STATES WILL FINALLY
MOVE AWAY FROM THE FORECAST AREA BY THE START OF THE EXTENDED
PERIOD. NUMERICAL GUIDANCE INDICATES A FAST NORTHWEST FLOW ALOFT
WILL SET UP OVER THE N-C PLAINS STATES IN THE TUE-WED TIME FRAME...
GRADUALLY TRANSITIONING TO A BROAD RIDGE THU-FRI...AND FINALLY TO
A WSW FLOW SAT-SUN.
SEVERAL FAST-MOVING SHORT WAVE TROUGHS WILL MOVE THROUGH THE
NORTHWEST FLOW EARLY IN THE PERIOD...IMPACTING MAINLY THE NORTHERN
PLAINS AND GREAT LAKES. THE FORECAST AREA WILL EXPERIENCE SEVERAL
COLD FRONTAL PASSAGES ASSOCIATED WITH THESE UPPER TROUGHS...BUT
NO PRECIPITATION AND LITTLE IN THE WAY OF CLOUDS IS ANTICIPATED.
THE FIRST COLD FRONT WILL MOVE THROUGH THE AREA MONDAY WHICH WILL
BRING DOWN A FAIRLY COLD CANADIAN AIR MASS TUESDAY WHICH MOVES OUT
WEDNESDAY. AFTERNOON TEMPERATURES WILL BE 8-12 DEGREES BELOW
NORMAL AS A RESULT TUE-WED WITH HIGHS 35-45F. PREFERRED AN SREF
SOLUTION FOR TEMPS DURING THIS PERIOD. A SECOND WEAKER COLD FRONT
WILL BRUSH THE AREA EARLY THURSDAY WITH MINIMAL IMPACT.
AS THE UPPER FLOW TRANSITIONS TO A BROAD RIDGE LATER IN THE
WEEK...HIGH TEMPERATURES WILL RETURN TO NORMAL WITH MID 40S-
LOWER 50S FORECAST FOR THU-SUN.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 441 PM MST SUN NOV 24 2013
MODEL PROBLEMS RESOLVING THE SNOW FIELD/BOUNDARY LAYER MOISTURE
MAKE THIS A LITTLE TRICKY TAF FORECAST. CURRENTLY AT KGLD WE ARE
HAVING MVFR CEILINGS AND LOOKING UPSTREAM THESE COULD CONTINUE FOR
A WHILE. CURRENT CONDITIONS ARE BETWEEN THE MORE PESSIMISTIC NAM
AND THE MAV WHICH IS SHOWING NOTHING. RUC IS RATHER AGGRESSIVE IN
RETURNING BOUNDARY LAYER MOISTURE THIS EVENING. NAM AND RUC HAVE
BEEN THE MOST AGGRESSIVE AND WRONG MODELS THE LAST FEW DAYS WITH
THE GFS BETTER BUT ALSO OVERDOING IT SOME.
SO FOR KGLD WILL GO WITH A PERSISTENCE FORECAST THROUGH THE
EVENING WITH THE MVFR CONDITIONS AND WATCH THE TRENDS. WILL KEEP
VFR AT KMCK FOR NOW THROUGH THE PERIOD. IF MORE MOIST MODELS ARE
RIGHT WILL NEED MORE STRATUS AND MAYBE SOME FOG. SOUTH WINDS WILL
LOSE THEIR GUSTINESS IN THE NEXT HOUR OR TWO. THEN WILL BE LIGHT
AND VARIABLE UNTIL A PREFRONTAL TROUGH/COLD FRONT MOVE THROUGH
LATER TONIGHT INTO TOMORROW WHICH WILL MAKE FOR STRONG AND GUSTY
WINDS DURING THE DAY.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...BULLER
SHORT TERM...JRM
LONG TERM...DLF
AVIATION...BULLER
AREA FORECAST DISCUSSION
NWS GOODLAND KS
450 PM MST SUN NOV 24 2013
.UPDATE...
ISSUED AT 441 PM MST SUN NOV 24 2013
UPDATED FORECAST DUE TO EXPIRED WIND ADVISORY. ALSO PER DIMINISHED
RADAR RETURNS REMOVED POPS FROM THE EASTERN PORTION OF THE FORECAST
AREA. ALSO ADJUSTED SKY COVER PER RECENT TRENDS.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 104 PM MST SUN NOV 24 2013
WATER VAPOR IMAGERY/RUC ANALYSIS INDICATED LARGE CLOSED H5 TROUGH
NEARING THE FOUR CORNERS AREA. AT THE SFC...STRONG PRESSURE
GRADIENT WAS IN PLACE ACROSS THE CWA WITH LOW DEEPENING OVER
COLORADO AND STRONG SFC RIDGE OVER EASTERN KS AND MO. NARROW AREA
OF STRONG WIND GUSTS IN EXCESS OF 40KTS...BETWEEN ITR AND GLD WAS
SLOWLY DIMINISHING.
WINDS SHOULD CONTINUE TO DECREASE AND FALL BELOW ADVISORY LEVELS
BEFORE SUNSET AS SFC COOLING ALLOWS BOUNDARY LAYER TO DECOUPLE. A
FEW LINGERING SNOW SHOWERS...WHICH LOOK LIKE THEY ARE BEING DRIVEN
BY ELEVATED CI WILL MOVE OUT OF THE AREA BY EARLY EVENING AS
POCKET OF DRY AIR SETTLES OVER THE AREA. UPPER LOW WILL NEAR THE
AREA TONIGHT AND WITH WEAK LIFT AND LOW STABILITY COULD SEE A
SHOWER OR TWO REDEVELOP AS IT PASSES. PROBABILITIES FROM ENSEMBLES
ARE VERY LOW AND GIVEN MUCH DRIER AIR MOVING INTO THE
AREA...CONFIDENCE NOT HIGH ENOUGH TO INCLUDE ATTM. WINDS WILL
DECREASE AND BECOME LIGHT TONIGHT PRIOR TO FRONTAL PASSAGE THAT
WILL BRING A PERIOD OF GUSTY NORTHERLY WINDS. WINDS ARE NOT
EXPECTED TO BE AS STRONG AS TODAY THOUGH. WITH A PERIOD OF LIGHT
WINDS AND SOME POTENTIAL THINNING OF THE HIGH CLOUDS HAVE LOWERED
MIN TEMPS SEVERAL DEGREES...ESPECIALLY ACROSS SOUTHERN CWA.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 140 PM MST SUN NOV 24 2013
THE LARGE UPPER LOW OVER THE SOUTHWESTERN STATES WILL FINALLY
MOVE AWAY FROM THE FORECAST AREA BY THE START OF THE EXTENDED
PERIOD. NUMERICAL GUIDANCE INDICATES A FAST NORTHWEST FLOW ALOFT
WILL SET UP OVER THE N-C PLAINS STATES IN THE TUE-WED TIME FRAME...
GRADUALLY TRANSITIONING TO A BROAD RIDGE THU-FRI...AND FINALLY TO
A WSW FLOW SAT-SUN.
SEVERAL FAST-MOVING SHORT WAVE TROUGHS WILL MOVE THROUGH THE
NORTHWEST FLOW EARLY IN THE PERIOD...IMPACTING MAINLY THE NORTHERN
PLAINS AND GREAT LAKES. THE FORECAST AREA WILL EXPERIENCE SEVERAL
COLD FRONTAL PASSAGES ASSOCIATED WITH THESE UPPER TROUGHS...BUT
NO PRECIPITATION AND LITTLE IN THE WAY OF CLOUDS IS ANTICIPATED.
THE FIRST COLD FRONT WILL MOVE THROUGH THE AREA MONDAY WHICH WILL
BRING DOWN A FAIRLY COLD CANADIAN AIR MASS TUESDAY WHICH MOVES OUT
WEDNESDAY. AFTERNOON TEMPERATURES WILL BE 8-12 DEGREES BELOW
NORMAL AS A RESULT TUE-WED WITH HIGHS 35-45F. PREFERRED AN SREF
SOLUTION FOR TEMPS DURING THIS PERIOD. A SECOND WEAKER COLD FRONT
WILL BRUSH THE AREA EARLY THURSDAY WITH MINIMAL IMPACT.
AS THE UPPER FLOW TRANSITIONS TO A BROAD RIDGE LATER IN THE
WEEK...HIGH TEMPERATURES WILL RETURN TO NORMAL WITH MID 40S-
LOWER 50S FORECAST FOR THU-SUN.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 441 PM MST SUN NOV 24 2013
MODEL PROBLEMS RESOLVING THE SNOW FIELD/BOUNDARY LAYER MOISTURE
MAKE THIS A LITTLE TRICKY TAF FORECAST. CURRENTLY AT KGLD WE ARE
HAVING MVFR CEILINGS AND LOOKING UPSTREAM THESE COULD CONTINUE FOR
A WHILE. CURRENT CONDITIONS ARE BETWEEN THE MORE PESSIMISTIC NAM
AND THE MAV WHICH IS SHOWING NOTHING. RUC IS RATHER AGGRESSIVE IN
RETURNING BOUNDARY LAYER MOISTURE THIS EVENING. NAM AND RUC HAVE
BEEN THE MOST AGGRESSIVE AND WRONG MODELS THE LAST FEW DAYS WITH
THE GFS BETTER BUT ALSO OVERDOING IT SOME.
SO FOR KGLD WILL GO WITH A PERSISTENCE FORECAST THROUGH THE
EVENING WITH THE MVFR CONDITIONS AND WATCH THE TRENDS. WILL KEEP
VFR AT KMCK FOR NOW THROUGH THE PERIOD. IF MORE MOIST MODELS ARE
RIGHT WILL NEED MORE STRATUS AND MAYBE SOME FOG. SOUTH WINDS WILL
LOSE THEIR GUSTINESS IN THE NEXT HOUR OR TWO. THEN WILL BE LIGHT
AND VARIABLE UNTIL A PREFRONTAL TROUGH/COLD FRONT MOVE THROUGH
LATER TONIGHT INTO TOMORROW WHICH WILL MAKE FOR STRONG AND GUSTY
WINDS DURING THE DAY.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...BULLER
SHORT TERM...JRM
LONG TERM...DLF
AVIATION...BULLER
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
219 PM CST Sat Nov 23 2013
...Updated short term discussion...
.SYNOPSIS...
ISSUED AT 1109 AM CST SAT NOV 23 2013
At 12z Saturday a -25c 500mb low was located over southern
California. A 300mb +100kt jet streak extended from the based of
this upper low northeast into the four corners region. A 700mb to
500mb deformation zone was located from Wyoming, across Colorado,
into Oklahoma and a 700mb baroclinic zone extended from southern
Colorado into northern Oklahoma. Along and south of this
baroclinic zone was also where the better 850mb to 500mb moisture
appears to be located based on upper air analysis. A surface to
850mb ridge axis extended from northeast New Mexico into southern
Nebraska. An area of high pressure at the surface at 12z was
located over the eastern Dakotas. The Dodge City sounding this
morning indicated a of drier air was located in the 900mb to 750mb
layer, however the Amarillo sounding indicated a deep layer of
moisture extending from the surface to the 700mb layer.
&&
.SHORT TERM...(This evening through Sunday)
ISSUED AT 218 PM CST SAT NOV 23 2013
Models this morning were all in decent agreement with the
southern California upper low slowly moving east across the
southwest United States over the next 24 hours. Ahead of this
upper trough, isentropic lift and moisture on the I290 and I295
surfaces will improve across southwest Kansas. As this moisture
and lift improves the clouds will thicken and lower with even some
light snow becoming possible across far southwest Kansas after 03z
based on the NAM. The latest HRRR was even a bit more aggressive
with the precipitation spreading into southwest Kansas after 00z
Sunday, and currently given the precipitation that was already
occurring near Amarillo as of 19z will begin to trend toward this
slightly quicker solution. This area of light snow will then
spread north and east through the overnight period but the better
moisture return and isentropic lift still appears to be confined
near and south of the Oklahoma border overnight. As a result not
expected much in the way of accumulation until the 300mb jet,
which was located over Arizona at 12z, begins to approach
southwest Kansas after 06z. Possible exception to this will be
extreme southwest Kansas near Elkhart.
Steady light snow will spread across southwest Kansas after 06z
Sunday as synoptic scale lift improves. Given that the moisture
and low level isentropic lift will already be in place am
currently leaning towards the NAM in snowfall amounts from roughly
06z to 18z Sunday. As a result snow amounts ranging from one to
around two inches still appear reasonable south of a Ulysses to
Dodge City to Pratt line. The higher 2 inch amounts will be mainly
confined near the Oklahoma border on Sunday. Given snow amounts of
around 2 inches being possible near the Oklahoma border was
considering a winter weather advisory, however at this time given
that this is expected to be only a marginal event over a small
area have decided to hold off with any type of headlines. Snow
accumulations of less than one inch is likely further north given
the late timing of the isentropic lift and depth of dry air
forecast in the lower levels.
.LONG TERM...(Sunday night through Saturday)
ISSUED AT 150 PM CST SAT NOV 23 2013
Moderation of temperatures is expected in the extended period.
Values will start below normal Monday and end up around normal by
next Saturday. No precipitation is expected during the period as
moisture will remain well southeast of the area. A series of weak
front will move across the region next week with the main impact in
the form of wind shifts.
&&
.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
ISSUED AT 1109 AM CST SAT NOV 23 2013
VFR cigs will gradually lower this evening with MVFR cigs
developing at DDC and GCK after 03z as the lower levels of the
atmosphere saturates. Light snow will then be possible towards 12z
at DDC and GCK with ceilings continuing to lower to near IFR
criteria at DDC and GCK. At HYS the latest BUFR soundings
indicating VFR conditions likely through early Sunday morning.
Northeast winds at 10 to near 15 knots will decrease after sunset
and then gradually veer to the southeast overnight, as an area of
high pressure at the surface moves from the northern plains into
the mid Mississippi valley.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 18 29 23 37 / 20 30 10 10
GCK 18 30 21 38 / 20 30 10 10
EHA 22 29 23 35 / 80 60 10 10
LBL 22 30 22 34 / 80 70 10 10
HYS 13 31 20 39 / 0 20 10 10
P28 17 28 24 36 / 30 50 20 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...Burgert
SHORT TERM...Burgert
LONG TERM...Sugden
AVIATION...Burgert
AREA FORECAST DISCUSSION
NWS PADUCAH KY
212 PM CST Sat Nov 23 2013
.SHORT TERM...(This Evening through Sunday)
ISSUED AT 151 PM CST SAT NOV 23 2013
High confidence in short term. Very cold through the weekend.
Expect a real test of the pipes with nearly 40 hours of below
freezing temperatures this weekend. With one possible exception
around noon Sunday could slip above freezing for a few hours. We
did tap into the extremely dry aloft...around 10 percent rh...for
a couple hours today as dew points dropped below any horizontal
advection values...but have since risen considerably as the mixing
layer shallowed with the suns angle decline. Winds will back off
overnight and lose a lot of the gusts but they are not expected to
diminish at least until Sunday. A southerly flow is not expected
until next week.
.LONG TERM...(Sunday Night through Saturday)
ISSUED AT 151 PM CST SAT NOV 23 2013
Focus will continue to be on how to handle the complex mid
tropospheric pattern forecast to take shape across the conus early
to mid week. Upper cut off low over the SW U.S. is forecast to
track east Sunday through Monday, reaching S/SW Texas by 12z
Tuesday. Northern stream flow will remain strong out of Canada with
a general trof over the east Canada into the NE U.S. and Great Lakes
region. A lot could be written about model trends and the details.
We will refer you to WPC and their Model Diagnostic Discussion for
the extensive details (product PMDHMD). In short summary, the GFS
has been the most consistent (relatively speaking) model since
Thursday. It continues to keep the southern stream h5 low separate
and mostly uninfluenced by the northern steam, while the other
models are having difficulty in whether or not there will be
phasing aspect. This will depend on how much energy can dig SSE into
the Great Lakes, Upper Midwest mid level trof. The NAM has been
discounted at this time. The 12z UKMET favors the GFS and prior
ECMWF runs (not the 12z). Will use a blend of those models.
All in all, this will result in little change in the forecast.
Monday afternoon, and night, we will introduce some sprinkles or
flurries pretty much area wide, as the GFS tries to saturate the
925-700mb layer from the west ahead of trofs at h8/h7. This
elongated band has been present in the GFS for several model runs
now. Monday night through very early Tuesday evening, will keep
chance PoPs going across the SSE 1/3 or so of the area, with
essentially dry conditions to the north and west of the Ohio. As far
as precip type. Again given low confidence in the track and
evolution of the system, and also accounting for the impact the
arctic airmass may have on the area, will keep it R--/S--.
Additional adjustments will probably be required once the models can
resolve whether or not the southern stream system will remain its
own entity, or if there will be some kind of phasing aspect.
The forecast Wednesday through Saturday still looks dry. Another
blast of cold high pressure will develop and move southeast across
the east 1/2 of the CONUS. Temperatures will remain below normal.
&&
.AVIATION...
ISSUED AT 1055 AM CST SAT NOV 23 2013
Considerable high cloud cover continued to stream across the area.
NNW winds will persist through the afternoon, gusty at times
(15-20kt). Main challenge will be with strato-cu over the nrn 1/2
of IL. The RAP seems to handle this best, per 950-900mb layer rh
progs. Other models seem too dry. Will follow the RAP, and place a
hedge SCT deck near 3k/ft in, and leave it, since the RAP holds on
to the low level moisture all the way through 06z. Steady north
winds near 10 kts expected tonight.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
SHORT TERM...KH
LONG TERM...CN
AREA FORECAST DISCUSSION
NWS PADUCAH KY
1055 AM CST Sat Nov 23 2013
.UPDATE...
ISSUED AT 1055 AM CST SAT NOV 23 2013
Updated the AVIATION section.
&&
.SHORT TERM...(Today through Monday)
ISSUED AT 1246 AM CST SAT NOV 23 2013
Clouds will gradually disperse later today as satellite trends
become more entrenched. Cold day today still on tap with highs in
the upper 30s-mid 40s prevailing. Sat night still offers coldest
air with clear out and lows making their way into the teens.
High pressure settling across the PAH FA allows a brief warmup
Sunday as moisture increases from the west again. Pcpn chances
will ramp up by
.LONG TERM...(Monday Night through Friday)
ISSUED AT 215 AM CST SAT NOV 23 2013
Main long term forecast concern is the potential for a little wet
snow Monday night and Tuesday. Models are in good agreement that a
split flow pattern will exist Monday night and Tuesday. Our precip
potential will come from the southern stream system...which will
primarily affect the Gulf Coast states. The consensus solution of
the 00z model suite brings the northern fringe of measurable qpf up
to about the Ohio River. Looking at the thermal profiles from the
00z nam and 03z sref mean...the column would be almost entirely
below freezing except for the boundary layer. Therefore...precip
type should be mainly snow. Given that surface temps will be above
freezing and precip will be light...no impacts are anticipated on
travel. Precip type could be rain at times since boundary layer
temps will be just above freezing. Pops will be kept in the chance
category over southwest KY...and a dry forecast will continue in
most of southern IL and southeast MO.
Phasing of the northern and southern stream systems will occur to
our east on Wednesday...creating a rather strong East Coast storm.
This system will bring another shot of unseasonably cold air
southward across the mid section of the nation. 850 mb temps will
again fall to around minus 10...similar to the air mass that is
enveloping our region this weekend. Highs Wednesday will likely be
in the 30s in most places.
Looking to Thanksgiving and Friday...the upper level flow pattern
will become less amplified as the East Coast system exits to the
east. Temps will slowly moderate...possibly reaching seasonal norms
by the weekend. Dry conditions are expected for the holiday itself
and Friday.
&&
.AVIATION...
ISSUED AT 1055 AM CST SAT NOV 23 2013
Considerable high cloud cover continued to stream across the area.
NNW winds will persist through the afternoon, gusty at times
(15-20kt). Main challenge will be with strato-cu over the nrn 1/2
of IL. The RAP seems to handle this best, per 950-900mb layer rh
progs. Other models seem too dry. Will follow the RAP, and place a
hedge SCT deck near 3k/ft in, and leave it, since the RAP holds on
to the low level moisture all the way through 06z. Steady north
winds near 10 kts expected tonight.
..CN..
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS GRAY ME
545 PM EST SAT NOV 23 2013
.SYNOPSIS...
A COLD FRONT WILL CROSS THE REGION TONIGHT WITH A STRONG NORTHWEST
FLOW SETTING UP BEHIND IT. HIGH PRESSURE WILL BUILD SOUTH OF NEW
ENGLAND SUNDAY THROUGH MONDAY. A COLD FRONT WILL SLOWLY APPROACH
FROM THE WEST MONDAY NIGHT AND TUESDAY AND WILL CROSS THE REGION
TUESDAY NIGHT. LOW PRESSURE WILL MOVE UP THE EAST COAST ON
WEDNESDAY. HIGH PRESSURE WILL GRADUALLY BUILD IN FROM THE WEST
THURSDAY THROUGH FRIDAY. HIGH PRESSURE WILL CREST OVER THE REGION
ON FRIDAY.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
UPDATE...ARCTIC COLD FNT MAKING QUICK PROGRESS TOWARDS THE CWFA
ATTM. SHSN AND SQUALLS WILL BECOME MORE NUMEROUS AS IT APPROACHES
THIS EVENING. STRONG CAA IS DESTABILIZING THE LLVLS...ALLOWING
SHSN TO BECOME QUITE INTENSE AT TIMES. LOOKING AT UPSTREAM OBS AND
WEBCAMS...VSBYS WILL DROP TO 1/4SM OR LESS AT TIMES. HAVE ADDED
HEAVY SN WORDING TO SRN NH AND ADJACENT SWRN ME FOR THE NEXT
SEVERAL HOURS AS SQUALLS TRACK OVER THESE AREAS.
ADDITIONALLY...ABOVE FREEZING TEMPS TODAY WILL MEAN ROAD TEMPS
WILL BE WARM ENOUGH TO MELT SNFL INITIALLY. HOWEVER...RAPIDLY
FALLING TEMPS WILL MEAN THIS WILL REFREEZE...CREATING VERY ICY
ROADWAYS. SEEING AS THESE SHSN WILL BE CROSSING INTERSTATES
89...93...AND 95 THIS IS A CONCERN. USED A BLEND OF THE LATEST RAP
AND HRRR TO TREND POP OVER THE NEXT FEW HOURS. OTHERWISE FORECAST
LOOKS ON TRACK AS BITTER COLD HEADS TOWARDS THE REGION.
PREVIOUS DISCUSSION...AN ARCTIC COLD FRONT WILL BE MOVING THROUGH
LATE TONIGHT. WINDS WILL BE DROPPING OFF SOMEWHAT AND TURNING MORE
TO THE SW AHEAD OF THE FRONT THIS AFTERNOON AND THIS EVENING. ONCE
THE FRONT MOVES THROUGH WINDS WILL STIFFEN FROM THE NW. THERE IS
SOME INDICATION THAT A BAND OF SNOW WILL MOVE THROUGH SRN NH AND
SW MAINE AROUND MIDNIGHT. THIS BAND CAN BE SEEN ON RADAR MOVING
THROUGH THE ADIRONDACKS ATTM.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
FOR SUNDAY WE HAVE ISSUED A WIND ADVISORY. LOOKING AT BUFKIT DATA
SHOWS WINDS TO 40 TO 50 KTS DOWN TO 2K FEET WITH STEEP LAPSE
RATES. THE STRONGEST WINDS ARE LIKELY TO BE IN THE 18Z TO 03Z TIME
FRAME. WINDS GUSTS TO 45 TO 50 MPH ARE CERTAINLY POSSIBLE. EXPECT
THERE WILL BE POWER OUTAGES AS THE DAY GOES ON. TEMPERATURES WILL
RISE ABOUT 5 TO 10 DEGREES TOMORROW WHICH WILL PUT HIGH TEMPS IN
THE 20S MOST EVERYWHERE WITH SOME UPPER TEENS IN THE MOUNTAINS.
THIS IS A GOOD 20 DEGREES BELOW NORMAL. SNOW SHOWERS WILL BE
LIKELY IN THE MOUNTAINS WITH 1 TO 3 INCHES POSSIBLE. FOR SUNDAY
NIGHT WINDS WILL ABATE SOMEWHAT AFTER MIDNIGHT BUT TEMPS WILL
PLUNGE. EXPECT AROUND ZERO IN THE MOUNTAINS AND NEAR 10 AT THE
COAST. RECORD LOW FOR PORTLAND MONDAY IS 9 DEGREES. WILL BE CLOSE
TO THIS.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
RIDGE OF HIGH PRESSURE WILL CREST OVER THE REGION MONDAY BEFORE
SHIFTING OFFSHORE. EXPECT A SUNNY START TO THE DAY BEFORE HIGH
CLOUDS SPILL IN FROM THE WEST IN THE AFTERNOON. WILL BE ANOTHER COLD
ONE WITH HIGHS ONLY REACHING THE UPPER TEENS TO LOWER 20S NORTH AND
MID 20S TO NEAR 30 SOUTH.
AREA OF WEAK OVER-RUNNING AHEAD LOW PRESSURE MOVING THROUGH SOUTHERN
CANADA WILL PUSH IN FROM THE WEST MONDAY NIGHT BRINGING SOME LIGHT
SNOW TO THE REGION. BEST CHANCES OF PRECIP WILL BE IN NORTHERN ZONES
WHERE AN INCH OR TWO OF ACCUMULATION WILL BE POSSIBLE. ELSEWHERE
JUST LOOKING FOR A LIGHT DUSTING. LOOKING FOR LOWS IN THE MID TEENS
TO LOWER 20S.
CLOUDS AND LINGERING FLURRIES WILL GIVE WAY TO PARTLY SUNNY SKIES ON
TUESDAY. COLD FRONT APPROACHING FROM THE WEST MAY BRING SNOW SHOWERS
TO THE MOUNTAINS BY LATE IN THE DAY. SHOULD SEE A MUCH WARMER DAY
WITH TEMPS RANGING THROUGH THE 30S.
COLD FRONT WILL SWING THROUGH THE REGION TUESDAY NIGHT BRINGING A
CHANCE OF SNOW SHOWERS IN THE NORTH AND VARIABLE CLOUDS ACROSS
SOUTHERN AREAS. OVERNIGHT LOWS WILL RANGE THROUGH THE 20S.
MODELS STILL FAR APART ON WEDNESDAY WITH THE ECMWF BRINGING LOW
PRESSURE UP THE EAST COAST AND GFS TAKING THE SAME SYSTEM WELL
OFFSHORE. AT THIS POINT SUPER BLEND GIVING LIKELY POPS WITH A MIX OF
RAIN AND SNOW IN THE SOUTH AND SNOW IN THE FOOTHILLS AND NORTH. SO
POTENTIAL IS STILL THERE FOR SIGNIFICANT SNOW IN THE NORTH AND A
MESSY MIX IN THE SOUTH. HIGH TEMPS WILL RANGE THOUGH THE 30S TO
NEAR 40.
HIGH PRESSURE WILL GRADUALLY BUILD IN FROM THE WEST THURSDAY
THROUGH FRIDAY. EXPECT TEMPS ONCE AGAIN BELOW NORMAL THURSDAY AS
COLD CANADIAN AIR FLOODS IN ON A STRONG NORTHERLY WINDS. WILL SEE
TEMPS MODERATE SOMEWHAT ON FRIDAY AS HIGH PRESSURE CRESTS OVER THE
REGION.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
SHORT TERM...EXPECT MOSTLY VFR. BRIEF MVFR/IFR PSBL LATE TONIGHT
IN SNOW SHOWERS. HIE WILL SEE MOSTLY MVFR.
LONG TERM...VFR MONDAY THROUGH TUESDAY. IFR/LIFR CEILINGS AND VSBY
DEVELOPING ON WEDNESDAY. VFR THURSDAY.
&&
.MARINE...
SHORT TERM...GALE WARNING HAS BEEN ISSUED.
LONG TERM...GALES POSSIBLE ON WEDNESDAY.
&&
.CLIMATE...
SIGNIFICANT OUTBREAK OF EARLY SEASON COLD AIR WILL CHALLENGE SOME
LOCAL RECORDS OVER THE NEXT COUPLE OF DAYS. AT KPWM THE RECORD
COLD MAXIMUM TEMP FOR 11/24 IS 28 SET IN 1989. THE TEMP AROUND
MIDNIGHT TONIGHT WILL LIKELY BE THE WARMEST KPWM GETS ALL
DAY...AND WILL BE VERY CLOSE TO 28 DEG. ON 11/25 KPWM HAS A RECORD
COLD MAXIMUM TEMP OF 29 SET IN 1993. THE CURRENT FORECAST IS FOR A
HIGH TEMP AROUND 30. FOR LOW TEMP ON 11/25...KPWM SET A RECORD IN
2000 OF 9 DEG. THE CURRENT FORECAST IS FOR 11/25 IS A LOW TEMP
AROUND 10 DEG.
SIMILARLY FOR KCON...RECORD COLD MAXIMUM TEMP FOR 11/24 IS 27 SET
IN 2000. WHILE IN 1993 THE RECORD COLD MAXIMUM TEMP WAS SET AT 29.
THE RECORD LOW TEMP FOR 11/25 IS 5 DEG SET IN 1956 AND 2000.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...WIND ADVISORY FROM 7 AM SUNDAY TO 1 AM EST MONDAY FOR
MEZ007>009-012>014-018>028.
NH...WIND ADVISORY FROM 7 AM SUNDAY TO 1 AM EST MONDAY FOR
NHZ001>010-013-014.
MARINE...GALE WARNING FROM 7 AM SUNDAY TO 7 AM EST MONDAY FOR
ANZ150>154.
&&
$$
NEAR TERM...LEGRO
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1112 AM CST Sat Nov 23 2013
.SHORT TERM...(Today and Tonight)
Issued at 346 AM CST SAT NOV 23 2013
Regional radar indicates a few echoes of light precipitation over
eastern Kansas. At this time expect those echoes to represent some
mid to high based precipitation, occurring at roughly 10 to 12 kft,
where RAP soundings indicate the lowest level of saturation. Below
that level, soundings indicate very dry air, which will preclude any
of the precipitation from reaching the surface.
The cold weather will continue across the area through the rest of
the weekend as cold northerly air continues to filter into the
Central Plains. The major culprit for this abnormally cold period is
an incredibly anomalous surface ridge located right on the Canadian
border with North Dakota. Currently, observations in far southern
Canada indicated roughly 1050 mb for the surface ridge and
temperatures in the -15 to -20 range. This ridge will slide
south/southeast and become centered over northern Missouri late
Saturday night into early Sunday morning. NAM has the surface ridge
approaching 1050 mb even as it becomes centered over the KC Metro
Sunday morning. Should the ridge maintain 1045 to 1050 mb as it
moves into the KC Metro its anomaly would carry nearly 4 standard
deviations from the seasonal normal, an incredible value.
Ahead of this ridge, cold air will continue to move into northern
and central Missouri causing temperatures on Saturday to remain
extremely chilly, with highs generally remaining in the lower to
middle 20s along and north of Interstate 70, with perhaps a few
areas south of Interstate 70 reaching the lower 30s.
As the aforementioned ridge moves overhead Saturday night the skies
will clear and winds will go calm, providing an incredible
opportunity for the surface to radiate outward. The result will be
record - or at the very least - near record temperatures for Sunday
morning across all of eastern Kansas and northern/central Missouri.
Even though the source region of this ridge demonstrates
temperatures well below 0 the lack of snow cover across areas north
of the forecast area will allow the airmass to modify. At this time
we can expect temperatures along and north of Interstate 70 to be in
the single digits - near zero degrees - Sunday morning, with areas
along Interstate 70 being near 10 degrees, and areas south of the
interstate being in the 10 to 15 degree range (See Climate portion
of the AFD for record lows for 11/24 in the KC Metro and St.
Joseph). Wind chills for Sunday morning will closely resemble the
morning lows, since the ridge being parked overhead will generally
prevent much in the way of surface flow, but ironically the coldest
wind chills Sunday morning could occur south of Interstate 70 where
light easterly winds in combination with the cold temperatures could
bring wind chill values to near zero. Only a modest diurnal warming
can be expected for Sunday as sunshine and perhaps the beginning of
southerly return flow could aid in getting the temperatures back
near the middle 30s by Sunday afternoon.
Very little - if any - relief from the cold temperatures are
expected through the early part of next week. In fact, after
Monday`s "warming" trend back into the lower 40s, expect another
cold front to blast through the area pulling temperatures back into
the 20s and 30s for Tuesday. At this time will continue a dry
forecast into the early part of the week, but there is a hint that
there could be some extremely light snowfall on Sunday night into
Monday morning. Southerly return flow late Sunday could usher a very
tiny amount of low level moisture into the area and spread it over
the aforementioned very cold surface temperatures. With a southern
stream cutoff low over the 4 Corner region, and a northern stream
long wave trough gently sagging southward into the area there could
be some ascent interaction with the moisture, however at this point
it was very difficult to even find modest lift. So, as previously
mentioned, have gone with a dry forecast for Sunday night, but
upcoming shifts will need to monitor the chances for very light,
likely non-accumulating, snow for Sunday night into Monday morning.
.LONG TERM...(Sunday through Friday)
Issued at 346 AM CST SAT NOV 23 2013
For Tuesday, and through the rest of the week, cool and dry
conditions are expected to prevail. Medium range operational and
ensemble models all point at Tuesday arriving with a trough swinging
through the center of the nation. Below the base of the trough a
cutoff low --currently noted spinning over Southern California--
will be phasing with the larger synoptic trough. Models continue to
show strong agreement that the cutoff low, even as it phases into
the base of trough, will stay south of Kansas and Missouri as it
transits the nation, thus allowing still more cold dry Canadian air
to slip south into the Plains States as a northwest flow prevails.
However, by late in the work week Tuesdays prevailing trough will
have pivoted fare to our east, and with another shortwave trough
expected to drop into the West Coast the flow across the center of
the nation should transit to more of a zonal flow across the Plains,
thus allowing a little moderation in our temperatures for the tail
end of the week. Thus, at this time, dry weather is expected, with
highs in the 30s prevailing Tuesday and Wednesday, creeping into the
40s for Friday and Saturday.
&&
.AVIATION...(For the 18Z TAFS through 18Z Sunday Afternoon)
Issued at 1110 AM CST SAT NOV 23 2013
VFR conditions expected through the period. Wind speeds will greatly
decrease post-sunset, likely becoming variable as the surface high
shifts over the area. Southeasterly winds will return after sunrise
as the sfc high moves east.
&&
.CLIMATE...
Issued at 346 AM CST SAT NOV 23 2013
Record lows for November 24...
Value Date
Kansas City 9 11/24/1950
St. Joseph 9 11/24/1950
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
SHORT TERM...Leighton
LONG TERM...Cutter
AVIATION...Blair
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
531 AM CST Sat Nov 23 2013
.SHORT TERM...(Today and Tonight)
Issued at 346 AM CST SAT NOV 23 2013
Regional radar indicates a few echoes of light precipitation over
eastern Kansas. At this time expect those echoes to represent some
mid to high based precipitation, occurring at roughly 10 to 12 kft,
where RAP soundings indicate the lowest level of saturation. Below
that level, soundings indicate very dry air, which will preclude any
of the precipitation from reaching the surface.
The cold weather will continue across the area through the rest of
the weekend as cold northerly air continues to filter into the
Central Plains. The major culprit for this abnormally cold period is
an incredibly anomalous surface ridge located right on the Canadian
border with North Dakota. Currently, observations in far southern
Canada indicated roughly 1050 mb for the surface ridge and
temperatures in the -15 to -20 range. This ridge will slide
south/southeast and become centered over northern Missouri late
Saturday night into early Sunday morning. NAM has the surface ridge
approaching 1050 mb even as it becomes centered over the KC Metro
Sunday morning. Should the ridge maintain 1045 to 1050 mb as it
moves into the KC Metro its anomaly would carry nearly 4 standard
deviations from the seasonal normal, an incredible value.
Ahead of this ridge, cold air will continue to move into northern
and central Missouri causing temperatures on Saturday to remain
extremely chilly, with highs generally remaining in the lower to
middle 20s along and north of Interstate 70, with perhaps a few
areas south of Interstate 70 reaching the lower 30s.
As the aforementioned ridge moves overhead Saturday night the skies
will clear and winds will go calm, providing an incredible
opportunity for the surface to radiate outward. The result will be
record - or at the very least - near record temperatures for Sunday
morning across all of eastern Kansas and northern/central Missouri.
Even though the source region of this ridge demonstrates
temperatures well below 0 the lack of snow cover across areas north
of the forecast area will allow the airmass to modify. At this time
we can expect temperatures along and north of Interstate 70 to be in
the single digits - near zero degrees - Sunday morning, with areas
along Interstate 70 being near 10 degrees, and areas south of the
interstate being in the 10 to 15 degree range (See Climate portion
of the AFD for record lows for 11/24 in the KC Metro and St.
Joseph). Wind chills for Sunday morning will closely resemble the
morning lows, since the ridge being parked overhead will generally
prevent much in the way of surface flow, but ironically the coldest
wind chills Sunday morning could occur south of Interstate 70 where
light easterly winds in combination with the cold temperatures could
bring wind chill values to near zero. Only a modest diurnal warming
can be expected for Sunday as sunshine and perhaps the beginning of
southerly return flow could aid in getting the temperatures back
near the middle 30s by Sunday afternoon.
Very little - if any - relief from the cold temperatures are
expected through the early part of next week. In fact, after
Monday`s "warming" trend back into the lower 40s, expect another
cold front to blast through the area pulling temperatures back into
the 20s and 30s for Tuesday. At this time will continue a dry
forecast into the early part of the week, but there is a hint that
there could be some extremely light snowfall on Sunday night into
Monday morning. Southerly return flow late Sunday could usher a very
tiny amount of low level moisture into the area and spread it over
the aforementioned very cold surface temperatures. With a southern
stream cutoff low over the 4 Corner region, and a northern stream
long wave trough gently sagging southward into the area there could
be some ascent interaction with the moisture, however at this point
it was very difficult to even find modest lift. So, as previously
mentioned, have gone with a dry forecast for Sunday night, but
upcoming shifts will need to monitor the chances for very light,
likely non-accumulating, snow for Sunday night into Monday morning.
.LONG TERM...(Sunday through Friday)
Issued at 346 AM CST SAT NOV 23 2013
For Tuesday, and through the rest of the week, cool and dry
conditions are expected to prevail. Medium range operational and
ensemble models all point at Tuesday arriving with a trough swinging
through the center of the nation. Below the base of the trough a
cutoff low --currently noted spinning over Southern California--
will be phasing with the larger synoptic trough. Models continue to
show strong agreement that the cutoff low, even as it phases into
the base of trough, will stay south of Kansas and Missouri as it
transits the nation, thus allowing still more cold dry Canadian air
to slip south into the Plains States as a northwest flow prevails.
However, by late in the work week Tuesdays prevailing trough will
have pivoted fare to our east, and with another shortwave trough
expected to drop into the West Coast the flow across the center of
the nation should transit to more of a zonal flow across the Plains,
thus allowing a little moderation in our temperatures for the tail
end of the week. Thus, at this time, dry weather is expected, with
highs in the 30s prevailing Tuesday and Wednesday, creeping into the
40s for Friday and Saturday.
&&
.AVIATION...(For the 12Z TAFS through 12Z Sunday Morning)
Issued at 529 AM CST SAT NOV 23 2013
No change to existing aviation forecast. Expect winds to be light and
variable tonight.
&&
.CLIMATE...
Issued at 346 AM CST SAT NOV 23 2013
Record lows for November 24...
Value Date
Kansas City 9 11/24/1950
St. Joseph 9 11/24/1950
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
SHORT TERM...Leighton
LONG TERM...Cutter
AVIATION...Leighton
CLIMATE...Leighton
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
355 AM CST Sat Nov 23 2013
.SHORT TERM...(Today and Tonight)
Issued at 346 AM CST SAT NOV 23 2013
Regional radar indicates a few echoes of light precipitation over
eastern Kansas. At this time expect those echoes to represent some
mid to high based precipitation, occurring at roughly 10 to 12 kft,
where RAP soundings indicate the lowest level of saturation. Below
that level, soundings indicate very dry air, which will preclude any
of the precipitation from reaching the surface.
The cold weather will continue across the area through the rest of
the weekend as cold northerly air continues to filter into the
Central Plains. The major culprit for this abnormally cold period is
an incredibly anomalous surface ridge located right on the Canadian
border with North Dakota. Currently, observations in far southern
Canada indicated roughly 1050 mb for the surface ridge and
temperatures in the -15 to -20 range. This ridge will slide
south/southeast and become centered over northern Missouri late
Saturday night into early Sunday morning. NAM has the surface ridge
approaching 1050 mb even as it becomes centered over the KC Metro
Sunday morning. Should the ridge maintain 1045 to 1050 mb as it
moves into the KC Metro its anomaly would carry nearly 4 standard
deviations from the seasonal normal, an incredible value.
Ahead of this ridge, cold air will continue to move into northern
and central Missouri causing temperatures on Saturday to remain
extremely chilly, with highs generally remaining in the lower to
middle 20s along and north of Interstate 70, with perhaps a few
areas south of Interstate 70 reaching the lower 30s.
As the aforementioned ridge moves overhead Saturday night the skies
will clear and winds will go calm, providing an incredible
opportunity for the surface to radiate outward. The result will be
record - or at the very least - near record temperatures for Sunday
morning across all of eastern Kansas and northern/central Missouri.
Even though the source region of this ridge demonstrates
temperatures well below 0 the lack of snow cover across areas north
of the forecast area will allow the airmass to modify. At this time
we can expect temperatures along and north of Interstate 70 to be in
the single digits - near zero degrees - Sunday morning, with areas
along Interstate 70 being near 10 degrees, and areas south of the
interstate being in the 10 to 15 degree range (See Climate portion
of the AFD for record lows for 11/24 in the KC Metro and St.
Joseph). Wind chills for Sunday morning will closely resemble the
morning lows, since the ridge being parked overhead will generally
prevent much in the way of surface flow, but ironically the coldest
wind chills Sunday morning could occur south of Interstate 70 where
light easterly winds in combination with the cold temperatures could
bring wind chill values to near zero. Only a modest diurnal warming
can be expected for Sunday as sunshine and perhaps the beginning of
southerly return flow could aid in getting the temperatures back
near the middle 30s by Sunday afternoon.
Very little - if any - relief from the cold temperatures are
expected through the early part of next week. In fact, after
Monday`s "warming" trend back into the lower 40s, expect another
cold front to blast through the area pulling temperatures back into
the 20s and 30s for Tuesday. At this time will continue a dry
forecast into the early part of the week, but there is a hint that
there could be some extremely light snowfall on Sunday night into
Monday morning. Southerly return flow late Sunday could usher a very
tiny amount of low level moisture into the area and spread it over
the aforementioned very cold surface temperatures. With a southern
stream cutoff low over the 4 Corner region, and a northern stream
long wave trough gently sagging southward into the area there could
be some ascent interaction with the moisture, however at this point
it was very difficult to even find modest lift. So, as previously
mentioned, have gone with a dry forecast for Sunday night, but
upcoming shifts will need to monitor the chances for very light,
likely non-accumulating, snow for Sunday night into Monday morning.
.LONG TERM...(Sunday through Friday)
Issued at 346 AM CST SAT NOV 23 2013
For Tuesday, and through the rest of the week, cool and dry
conditions are expected to prevail. Medium range operational and
ensemble models all point at Tuesday arriving with a trough swinging
through the center of the nation. Below the base of the trough a
cutoff low --currently noted spinning over Southern California--
will be phasing with the larger synoptic trough. Models continue to
show strong agreement that the cutoff low, even as it phases into
the base of trough, will stay south of Kansas and Missouri as it
transits the nation, thus allowing still more cold dry Canadian air
to slip south into the Plains States as a northwest flow prevails.
However, by late in the work week Tuesdays prevailing trough will
have pivoted fare to our east, and with another shortwave trough
expected to drop into the West Coast the flow across the center of
the nation should transit to more of a zonal flow across the Plains,
thus allowing a little moderation in our temperatures for the tail
end of the week. Thus, at this time, dry weather is expected, with
highs in the 30s prevailing Tuesday and Wednesday, creeping into the
40s for Friday and Saturday.
&&
.AVIATION...(For the 06Z TAFS through 06Z Saturday Night)
Issued at 1110 PM CST FRI NOV 22 2013
VFR conditions are expected through the entire forecast as deeper, drier
air continues to build into the region from the north. Despite the
absence of lower clouds, a steady stream of mid to upper level
moisture should keep things cloudy with high level clouds. Winds will
be persistent from the north, increasing some tomorrow morning and
becoming gusty. Winds should diminish very late in the valid period
as high pressure builds into the region.
&&
.CLIMATE...
Issued at 346 AM CST SAT NOV 23 2013
Record lows for November 24...
Value Date
Kansas City 9 11/24/1950
St. Joseph 9 11/24/1950
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
SHORT TERM...Leighton
LONG TERM...Cutter
AVIATION...CDB
CLIMATE...Leighton
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
615 PM CST SUN NOV 24 2013
.SYNOPSIS...
ISSUED AT 235 PM CST SUN NOV 24 2013
AN UPPER LOW SPUN OVER THE FOUR CORNERS ON SUNDAY AFTERNOON...WHICH
PUSHED SOME MID AND HIGH LEVEL CLOUDS INTO SOUTHERN NEBRASKA. WITH
THE UPPER LOW TO THE SOUTH...WESTERLY FLOW ALOFT HAS ALLOWED FOR A
THERMAL RIDGE TO MOVE INTO THE NORTHERN PLAINS TODAY WHERE 850MB
TEMPERATURES WERE GENERALLY 5C TO 10C AS OF 12Z THIS MORNING
COMPARED TO 0C TO-5C ACROSS NEBRASKA. LOOKING AT WATER VAPOR...COULD
MAKE OUT THE NEXT LOW PRESSURE SYSTEM IN LINE IN THE NORTHWEST FLOW
OVER SASKATCHEWAN...WITH ANOTHER BATCH OF COLD ARCTIC AIR BEHIND IT.
&&
.SHORT TERM...(THIS AFTERNOON THROUGH MONDAY)
ISSUED AT 235 PM CST SUN NOV 24 2013
THE UPPER LEVEL LOW OVER THE FOUR CORNERS IS EXPECTED TO START
GETTING INFLUENCED BY THE MEAN NORTHWEST FLOW AND START TO PUSH INTO
TEXAS BY THE END OF THE DAY MONDAY. THIS SHOULD ALLOW FOR THE MID
AND HIGH CLOUDS THAT HAVE BEEN SPINNING AROUND THIS SYSTEM INTO THE
SOUTHERN PART OF THE FORECAST AREA FOR THE PAST SEVERAL DAYS TO GET
PULLED SOUTHWARD AND AWAY FROM THE LOCAL AREA TONIGHT AND MONDAY
MORNING. IT WILL ALSO ALLOW FOR SOME OF THE COLDER AIR ASSOCIATED
WITH THAT SYSTEM TO GET PUSHED AWAY FROM THE AREA. MEANWHILE...THE
LOW PRESSURE SYSTEM OVER SASKATCHEWAN WILL MOVE INTO ONTARIO WHICH
WILL DRAG A COLD FRONT ACROSS NEBRASKA TONIGHT AND MONDAY MORNING.
ALTHOUGH TEMPERATURES BEHIND THE FRONT WON/T BE MUCH COLDER FOR THE
LOCAL AREA. WINDS WILL SWITCH TO THE NORTH-NORTHWEST BEHIND THE
FRONT. FORECAST SOUNDINGS ARE SHOWING MINIMAL MIXING MONDAY
AFTERNOON...BUT WINDS JUST ABOVE THE SURFACE ARE ABOUT 25KTS SO
COULD SEE SOME 20KT WINDS AT GROUND LEVEL DURING THE AFTERNOON.
ONE CONCERN WITH THE FORECAST WILL BE THE POTENTIAL FOR THE
DEVELOPMENT OF SHALLOW STRATUS THIS EVENING AND TONIGHT FROM
SOUTHWEST INTO CENTRAL NEBRASKA. LOW LEVEL MOISTURE ADVECTION IS
BEING INDICATED INTO THE AREA AHEAD OF THE FRONT BY SEVERAL FORECAST
MODELS...WITH THE NAM BEING THE MOST ROBUST SPREADING STRATUS ACROSS
THE ENTIRE FORECAST AREA. DISCOUNTING THAT MODEL AND LOOKING CLOSER
TO THE RAP WHICH HAS BEEN HOLDING OFF THE LOW LEVEL MOISTURE FROM
MOVING INTO NEBRASKA THROUGH THE DAY TODAY. ALTHOUGH IT HAS KEPT
THIS MOISTURE SOUTH TODAY...IT DOES CONTINUE TO PUSH IT INTO
NEBRASKA THIS EVENING...WITH CLOUDS REMAINING UNTIL THE FRONT PUSHES
THROUGH LATE TONIGHT AND MONDAY MORNING. WATCHING THE STRATUS
STRUGGLE TO DEVELOP IN UPSTREAM AREAS TODAY...AND WITH THE RAP
CONTINUOUSLY BACKING OFF ON THE TIMING OF BRINGING IT NORTH...JUST
DON/T HAVE THE CONFIDENCE THAT THE CLOUDS WILL GET INTO THE LOCAL
AREA TONIGHT AND THE FORECAST TAKES THAT INTO ACCOUNT. IF THE
STRATUS DOES MOVE IN...MAY HAVE TO TAKE A LOOK AT LOW TEMPERATURES
TONIGHT...ALTHOUGH THEY SHOULDN/T HAVE AN IMPACT ON HIGHS MONDAY AS
THEY WOULD BE PUSHED OUT OF THE AREA BEFORE PEAK HEATING.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 235 PM CST SUN NOV 24 2013
A REINFORCING SHOT OF ARCTIC AIR WILL MOVE THROUGH THE DAKOTAS
INTO NEBRASKA MONDAY NIGHT AND TUESDAY. THIS WILL BRING A GLANCING
BLOW OF COLDER AIR...WHICH IS ACTUALLY NOT AS COLD AS THE PREVIOUS
ONE SATURDAY. WENT A FEW DEGREES ABOVE GUIDANCE LOWS MONDAY NIGHT
WITH MID/UPPER TEENS. WEAK COLD AIR ADVECTION TUESDAY WITH H85
TEMPS AS LOW AS -15C PER NAM MODEL. THIS LOOK TOO COLD AND FAVORED
THE GFS -11C. USING CONSALL INTO A BLEND HIGHS NEAR 25 AT ONL TO
36 AT IML. TEMPERATURES THEN WARMUP FOR WEDNESDAY. AS SURFACE HIGH
SLIDES EAST...A RETURN SOUTH TO SOUTHWEST FLOW DEVELOPS. WHILE
HIGHS TO BE LIMITED TO NEAR 30 AT BBW AND ONL...THE WESTERN TIER
OF COUNTIES TO WARM TO 40-43 DEGREES. DRY CONDITIONS TO ALSO PREVAIL.
FOR THANKSGIVING DAY THROUGH THE WEEKEND...DRY AND SEASONAL
TEMPERATURES ARE FORECAST. THE UPPER FLOW WILL REMAIN FAIRLY
ZONAL. THIS HIGHLIGHTED BY AN UPPER TROUGH DIGGING FROM BRITISH
COLUMBIA INTO THE NORTHERN PLAINS AND A CLOSED LOW REMAINING OFF
THE CALIF. COAST. ONLY A WEAK COLD FRONT INDICATED FRIDAY
NIGHT...WHICH SHOULD HAVE MINIMAL IMPACT TO HIGHS SATURDAY AND
SUNDAY. ONLY VERY MINOR CHANGES TO HIGHS THROUGH THIS WEEKEND WITH
MAINLY UPPER 30S TO MID 40S.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 614 PM CST SUN NOV 24 2013
OVER THE NEXT 24 HOURS...MID LEVEL CLOUDINESS WILL CONTINUE TO
STREAM INTO SOUTHERN NEBRASKA IN ASSOCIATION WITH AN UPPER LEVEL
LOW WHICH WILL TRACK ACROSS THE SOUTHERN PLAINS. FOR THE KLBF
TERMINAL...BROKEN TO OVERCAST CIGS AON 10000 FT AGL WILL CONTINUE
INTO THE OVERNIGHT HOURS. THERE IS A SMALL THREAT FOR LOWER CLOUDS
ACROSS SOUTHWESTERN NEBRASKA OVERNIGHT
TONIGHT...HOWEVER...FORECAST CONFIDENCE IN THIS OCCURRING IS LOW
ATTM AND WILL LEAVE IT OUT OF THE 00Z FORECAST. FOR MONDAY...HIGH
CLOUDINESS IS POSSIBLE WITH SCATTERED CIGS AON 15000 FT AGL. FOR
THE KVTN TERMINAL...HIGH CLOUDS AON 20000 FT AGL ARE POSSIBLE OVER
THE NEXT 24 HOURS. AT BOTH TERMINALS...SOUTHERLY WINDS AT AROUND
10 KTS WILL SHIFT TO THE NORTH AROUND 09Z AT THE KVTN TERMINAL AND
AROUND 12Z AT THE KLBF TERMINAL. WIND SPEEDS WILL BE AROUND 10 KTS
MONDAY...AND MAY GUST TO 20 KTS MONDAY AFTERNOON.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BROOKS
SHORT TERM...BROOKS
LONG TERM...ROBERG
AVIATION...CLB
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
521 AM CST SAT NOV 23 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 309 AM CST SAT NOV 23 2013
1050 MB ARCTIC HIGH PRESSURE CENTERED NEAR MINOT ND THIS MORNING
WILL DROP SOUTH THROUGH THE UPPER MISSOURI RIVER BASIN AND BE
CENTERED NEAR KANSAS CITY BY 12Z SUNDAY. AN ARCTIC COLD FRONT WILL
BACK PART WAY INTO THE FCST AREA THIS MORNING AND THEN LIFT NORTH
A BIT TONIGHT. A BANK OF STRATUS DEVELOPING BETWEEN
PHILIP...WINNER AND AINSWORTH IS EXPECTED TO EXPAND WEST AND
SOUTH...PERHAPS TO INTERSTATE 80 BY 15Z THIS MORNING.
THE MODELS APPEAR TO BE OVERFORECASTING THIS CLOUD COVER AND THIS IS
TYPICAL WITH FRESH SNOW COVER. MID AND HIGH LEVEL CLOUDINESS BLOWING
OFF FROM THE SWRN U.S. UPPER LEVEL LOW IS EXPECTED TO CONTINUE
ACROSS THE SRN HALF OF THE FCST AREA TODAY AND TONIGHT AND THE BANK
OF STRATUS SHOULD SLOWLY ERODE THIS AFTERNOON ACROSS NCNTL NEB. NOTE
THE RAP13 HANGS THE STRATUS ACROSS VALENTINE ALL DAY THROUGH 00Z.
FCST ERRORS WITH CLOUD COVER COULD BE LARGE TODAY AND TONIGHT.
ALL OF THIS SUGGESTS TEMPS WILL REMAIN BELOW FREEZING ACROSS ALL OF
THE FCST AREA TODAY WITH TEENS IN THE NORTHEAST TO NEAR 30 ACROSS
THE WEST AND SOUTHWEST WHERE THE ARCTIC FRONT WILL NOT REACH. LOWS
TONIGHT SHOULD FALL INTO THE TEENS AND SINGLE DIGITS WITH THE
COLDEST LOWS IN THE NORTHEAST. A LOW LEVEL JET/STRONG RETURN FLOW
AROUND THE ARCTIC HIGH SETS UP ACROSS WRN NEB TONIGHT WHICH SHOULD
LIMIT LOWS TO THE TEENS.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 309 AM CST SAT NOV 23 2013
PERIOD WILL BE DOMINATED BY A LARGE BLOCKING RIDGE OF UPPER LEVEL
HIGH PRESSURE ACROSS THE NORTHERN ATLANTIC. THIS WILL CONTINUE TO
SUPPORT DEEP TROUGHING ACROSS THE HUDSON BAY AREA...WITH SHOTS OF
COLD ARCTIC AIR MOVING SOUTHEAST ACROSS CANADA INTO THE NORTHERN
AND EASTERN UNITED STATES ON THE WESTERN/SOUTHWESTERN SIDE OF THE
DEEP TROUGH. IT APPEARS THAT OUR AREA WILL BE ON THE SOUTHWEST
EDGE OF THESE ARCTIC AIR INTRUSIONS. IN FACT...WESTERN AND
SOUTHWEST NEBRASKA MAY STAY WEST OF THE ARCTIC AIR AND BE
DOMINATED BY A PACIFIC AIRMASS. THE ECMWF IS ADVERTISING A
POTENTIAL CHINOOK DOWNSLOPE EVENT BOTH WEDNESDAY AND
FRIDAY...WHICH COULD BOOST TEMPERATURES INTO THE 50S. WILL NOT
JUMP ONTO THIS SOLUTION FULLY...BUT WILL TREND TEMPS UP A DEGREE
OR TWO. OVERALL THE PATTERN APPEARS TO BE LOOKING A LITTLE WARMER
IN THE COMING DAYS. STILL NO PRECIPITATION EXPECTED AS A DRY
NORTHWEST FLOW ALOFT CONTINUES.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 514 AM CST SAT NOV 23 2013
THE MVFR/LOCAL IFR CIGS ACROSS NCNTL NEB IS EXPECTED TO DRIFT WEST
A BIT THIS MORNING AND THE LIFT NORTH AND OUT OF THE FCST AREA BY
AROUND 03Z THIS EVENING. THE MODELS ARE QUITE DIFFERENT WITH THE EXPANSE
AND DURATION OF THIS FEATURE BUT THE RAP APPEARS TO BE VERIFYING
THE BEST AND IS THE BASIS FOR THE FORECAST.
THE STRATUS COULD ACTUALLY MOVE WEST OF KVTN THIS MORNING WITH VFR
DEVELOPING. SO THE RAP IS THE BEST MODEL BUT THE EXPANSE AND
LOCATION OF THE STRATUS REMAINS UNCERTAIN.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CDC
LONG TERM...TAYLOR
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS BUFFALO NY
1006 AM EST SAT NOV 23 2013
.SYNOPSIS...
AN ARCTIC COLD FRONT WILL CROSS THE REGION EARLY THIS AFTERNOON WITH
A FEW SNOW SHOWERS OR BRIEF SQUALLS. THIS FRONT WILL USHER IN THE
COLDEST AIR OF THE SEASON SO FAR WITH AREAS OF LAKE EFFECT SNOW
SOUTHEAST OF THE LAKES TONIGHT AND SUNDAY. TEMPERATURES WILL
MODERATE SOME EARLY NEXT WEEK BUT REMAIN BELOW AVERAGE. A FRESH
BATCH OF VERY COLD AIR IS EXPECTED BY THANKSGIVING WITH FREQUENT
CHANCES OF SOME LIGHT SNOW THROUGH THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
OUR WEATHER WILL BECOME CONSIDERABLY MORE WINTRY IN THE NEXT
COUPLE HOURS AS A STRONG ARCTIC FRONT MOVES ACROSS OUR REGION
DURING THE AFTERNOON HOURS. AHEAD OF THIS...SOME LAKE EFFECT SNOWS
HAVE DEVELOPED EAST OF LAKE ONTARIO. BECAUSE THESE MAY PRODUCE
SOME PRE-FRONTAL SNOW ACCUMULATIONS HAVE MOVED UP THE TIMING OF
THE ADVISORY EAST OF LAKE ONTARIO BY A COUPLE HOURS...HOWEVER
THESE ACCUMULATIONS WILL BE NORTH OF THE STEADIEST POST-FRONTAL
SNOWS SO THE STORM TOTALS REMAIN THE SAME. ELSEWHERE IS A MIX OF
SUN AND CLOUDS...WHICH WILL QUICKLY FILL IN WITH THE PASSAGE OF
THE FRONT. SPEAKING OF THE COLD FRONT...AT 1000 AM THE BOUNDARY
HAD JUST REACHED TORONTO. FOLLOWING THE HRRR TIMING...EXPECT THE
FRONT TO REACH BUFFALO AROUND NOON...AS IT QUICKLY DROPS TO THE
SOUTHWEST. THIS WILL BRING A ROUND OF SNOW SHOWERS WITH THE
FRONT...BEFORE THE EVENT EVOLVES INTO A LAKE EFFECT ONE. MOST
LOCATIONS ARE AT OR NEAR DAYTIME HIGHS LATE THIS MORNING..WITH
TEMPERATURES FALLING INTO THE 20S BEHIND THE ARCTIC FRONT THIS
AFTERNOON.
BY NOONTIME OR SHORTLY AFTER THE STRONG ARCTIC FRONT WILL CROSS THE
REGION FROM NORTHWEST TO SOUTHEAST ALONG WITH A SHARP MID LEVEL
TROUGH AND VORTICITY MAXIMA. THIS WILL PRODUCE A BRIEF BAND OF SNOW
SHOWERS IN MOST AREAS. THE ARCTIC FRONT WILL BRIEFLY BECOME LAKE
ENHANCED AS WELL EAST OF BOTH LAKES WITH A BRIEF BURST OF HEAVIER
SNOW OFF LAKE ERIE FROM THE BUFFALO SOUTHTOWNS INTO THE SOUTHERN
TIER. THIS MAY PRODUCE A QUICK INCH OR SO OF ACCUMULATION. A SIMILAR
EFFECT WILL TAKE PLACE EAST OF LAKE ONTARIO AN HOUR OR TWO LATER.
OUTSIDE OF LAKE EFFECT AREAS ANY ACCUMULATION WILL BE VERY LIGHT...
A DUSTING TO HALF INCH.
THE MAIN CONCERN CONTINUES TO REVOLVE AROUND LAKE EFFECT POTENTIAL
BEHIND THE ARCTIC FRONT. 850MB TEMPS DROP TO AROUND -18C TONIGHT
WHICH WILL SUPPORT EXTREME INSTABILITY WITH LAKE INDUCED EQUILIBRIUM
LEVELS RISING TO 17K FEET OR BETTER. THE MAIN MITIGATING FACTORS TO
A LARGER EVENT WILL BE A SHORT NORTHWEST FETCH AND RELATIVELY
SHALLOW AND SPARSE SYNOPTIC SCALE MOISTURE.
OFF LAKE ONTARIO...
THERE WILL BE A LITTLE LONGER PERIOD OF WESTERLY FLOW ALONG AND JUST
BEHIND THE ARCTIC FRONT THIS AFTERNOON AS BOTH THE NAM AND GFS HAVE
A WEAK FRONTAL WAVE CROSSING THROUGH THE SAINT LAWRENCE VALLEY NEAR
THE CORE OF STRONGEST DPVA AHEAD OF THE MID LEVEL TROUGH. THIS WAVE
SHOULD BRING A BRIEF PERIOD OF DEEPER MOISTURE...AND THAT COMBINED
WITH UPSLOPE ENHANCEMENT ON THE TUG HILL SHOULD PRODUCE A BRIEF
WINDOW OF HEAVIER SNOW. MAY SEE A QUICK 3-6 INCHES ON THE TUG HILL
DURING THE AFTERNOON AND EARLY EVENING...WITH 2-3 INCH AMOUNTS FOR
THE REST OF LEWIS COUNTY AND SOUTHERN/EASTERN JEFFERSON COUNTY.
BY MID EVENING FLOW WILL QUICKLY TURN NORTHWEST TO 310-320 DEGREES.
THIS WILL CARRY LAKE EFFECT SOUTH AND BREAK IT APART INTO MULTIPLE
BANDS...WITH THE FLOW VEERING FURTHER TO AROUND 330 DEGREES LATE
TONIGHT AND SUNDAY MORNING. NORTHWEST FLOW EVENTS ARE VERY SUBTLE
AND DIFFICULT TO PINPOINT WHERE GREATER ACCUMS WILL OCCUR. THE
HEAVIEST BAND MAY END UP BEING OVER CENTRAL AND SOUTHEAST OSWEGO
COUNTY WITH A SLIGHTLY LONGER FETCH AND ENHANCED CONVERGENCE
ORIGINATING FROM A CONCAVE SHAPED BAY ON THE NORTHERN SHORE NEAR
KINGSTON ONTARIO. ANOTHER MORE DOMINANT BAND ALSO TYPICALLY FORMS
FROM THE EASTERN SUBURBS OF ROCHESTER EAST ACROSS WAYNE COUNTY AND
NORTHEAST ONTARIO COUNTY...POSSIBLY CLIPPING CAYUGA COUNTY NEAR THE
THRUWAY.
FARTHER WEST...MESOSCALE MODELS AND OVERALL PATTERN CONTINUE TO
POINT TO THE POTENTIAL FOR A GEORGIAN BAY CONNECTION SOMEWHERE
BETWEEN ROCHESTER AND BUFFALO STARTING THIS EVENING. THESE ARE THE
MOST DIFFICULT OF ALL TO TIME AND PLACE...BUT CAN BRING VERY NARROW
CORRIDORS OF ENHANCED ACCUMULATION. WITH THIS IN MIND...HAVE OFFERED
SOME HIGHER ACCUMULATIONS IN THE FORECAST FOR EASTERN NIAGARA...
ORLEANS...AND GENESEE COUNTIES TONIGHT. THE FORECAST ACCUMULATIONS
ARE LIKELY TOO BROAD BRUSHED...BUT EXACT BAND PLACEMENT IS TOO
UNCERTAIN FOR ANY MORE DETAIL AT THIS TIME.
OFF LAKE ERIE...
FOLLOWING THE BRIEF BURST OF LAKE ENHANCEMENT EARLY THIS AFTERNOON
EXPECT MULTIPLE BANDS TO DEVELOP ON NORTHWEST FLOW...WITH UPSLOPE
ENHANCEMENT ACROSS THE HIGHER TERRAIN. THE SHORT FETCH WILL KEEP
THIS ACTIVITY RELATIVELY LIGHT MOST OF THE TIME ACROSS THE HIGHER
TERRAIN...ALTHOUGH PERSISTENCE MAY LEAD TO SOME DECENT SNOW TOTALS
THROUGH TONIGHT AND INTO SUNDAY ON THE CHAUTAUQUA RIDGE AND POSSIBLY
THE HILLS OF SOUTHERN ERIE/WYOMING COUNTIES. ACROSS SOUTHWEST
CHAUTAUQUA COUNTY AN UPSTREAM CONNECTION TO LAKE HURON IS STILL A
POSSIBILITY. MESOSCALE MODELS CONTINUE TO SHOW THE STRONGEST AND
MOST PERSISTENT LAKE HURON BAND TO BE OVER NORTHWEST PA...BUT IT MAY
OCCASIONALLY MIGRATE INTO SOUTHWEST CHAUTAUQUA COUNTY ESPECIALLY
THIS EVENING AND AGAIN ON SUNDAY. IF THIS OCCURS THERE WOULD BE
ENHANCED SNOW TOTALS IN PLACES SUCH AS SHERMAN AND CLYMER. AMOUNTS
WILL BE DRAMATICALLY LESS ALONG THE LAKESHORE WITHOUT THE BENEFIT OF
UPSLOPE FLOW.
AS FAR AS HEADLINES GO...DECIDED TO SIMPLIFY AND CHANGE ALL
HEADLINES TO THE LAKE EFFECT VARIETY. UNFORTUNATELY IN NORTHWEST
FLOW LAKE EFFECT SNOW ADVISORIES NEED TO BE BROAD BRUSHED FOR MANY
AREAS SOUTHEAST OF THE LAKES...BUT ACTUAL ADVISORY AMOUNTS WILL ONLY
BE REALIZED IN VERY NARROW BANDS WITH MANY AREAS COMING IN WITH
SUB-ADVISORY ACCUMULATIONS. THE LAKE EFFECT SNOW WARNING WILL REMAIN
FOR CHAUTAUQUA COUNTY...WITH THE BEST CHANCE OF WARNING CRITERIA
ONLY IN THE SOUTHWEST CORNER OF THE COUNTY. WILL KEEP OSWEGO COUNTY
AN ADVISORY FOR NOW...BUT IT IS POSSIBLE THIS COULD NEED UPGRADING
TO A WARNING IF A PERSISTENT BAND DEVELOPS OVER THE CENTRAL AND
SOUTHEAST PORTION OF THE COUNTY. NORTHWEST FLOW IS UNFAVORABLE FOR
THE CORRIDOR FROM NIAGARA FALLS TO THE BUFFALO METRO AREA...AND ALSO
ALLEGANY COUNTY SO THESE AREAS WERE REMOVED FROM HEADLINES.
IT WILL ALSO BECOME WINDY BEHIND THE ARCTIC FRONT WITH GUSTS IN THE
40-45 MPH RANGE...ESPECIALLY SOUTHEAST OF LAKE ONTARIO. THIS WILL
PRODUCE BLOWING AND DRIFTING SNOW IN AREAS WHICH RECEIVE MORE THAN
AN INCH OR TWO OF ACCUMULATION. TEMPERATURES WILL DROP INTO THE
TEENS TONIGHT IN ALL AREAS EXCEPT THE IMMEDIATE LAKESHORES. WIND
CHILLS WILL DROP TO NEAR ZERO AT TIMES LATE TONIGHT.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
A NORTHWEST FLOW OF VERY COLD AIR WILL IMPACT THE AREA ON SUNDAY.
AFTERNOON TEMPERATURES WILL STRUGGLE TO GET ABOVE THE LOWER
20S...AND SOME LOCATIONS ACROSS THE HIGHER ELEVATIONS EAST OF BOTH
LAKES WILL LIKELY SEE READINGS IN THE UPPER TEENS.
THESE VERY COLD TEMPERATURES WILL RESULT IN EXTREME INSTABILITY OVER
THE LAKES...WITH LAKE EQUILIBRIUM LEVELS EXPECTED TO RANGE FROM
15K-18K FEET...ESPECIALLY DURING THE FIRST HALF OF THE DAY. THE
LATEST BUFKIT PROFILES STILL SHOW PLENTY OF MOISTURE INTERSECTING
THE FAVORABLE SNOW GROWTH REGION AS WELL. AS A RESULT...ONGOING LAKE
SNOW BANDS WILL REMAIN INTACT THROUGHOUT THE DAY. THE ONE FACTOR
THAT WILL LIMIT SNOW ACCUMULATIONS WILL BE THE RELATIVELY SHORT
FETCH ACROSS THE LAKES. HOWEVER...THE MESOSCALE MODELS STILL
SUGGESTS THAT UPSTREAM CONNECTIONS TO LAKE HURON AND GEORGIAN BAY
WILL COME INTO PLAY AND HELP TO ENHANCE THE SNOWFALL AT TIMES. THIS
WILL BE ESPECIALLY TRUE ALONG THE CHAUTAUQUA RIDGE.
FOR LAKE ONTARIO...THE CONNECTION TO GEORGIAN BAY MAY HAVE THE
BIGGEST IMPACT ALONG THE WESTERN SHORES OF THE LAKE DURING THE
MORNING...INCLUDING AREAS NORTHEAST OF BUFFALO. AS THE BOUNDARY
LAYER WINDS BACK A LITTLE MORE DURING THE AFTERNOON...THE STEADIER
LAKE SNOWS MAY SHIFT TO THE EAST AND IMPACT AREAS SOUTHEAST OF THE
LAKE MORE.
THE COMBINATION OF SNOW AND NORTHWEST WINDS GUSTING UP TO ABOUT 30
MPH WILL CONTINUE TO HAVE A SIGNIFICANT IMPACT ON TRAVEL ACROSS THE
AREA ON SUNDAY. AS A RESULT...LAKE EFFECT SNOW WARNINGS/ADVISORIES
ARE IN PLACE AS OUTLINED BELOW.
SUNDAY NIGHT...HIGH PRESSURE AT THE SURFACE WILL SHIFT EAST INTO THE
MIDDLE ATLANTIC STATES. THIS WILL CAUSE THE BOUNDARY LAYER WINDS TO
BACK TO THE SOUTHWEST...WHILE THE LOW LEVEL SHEAR INCREASES. AT THE
SAME TIME...LAKE EQUILIBRIUM LEVELS WILL BE LOWERING AS TEMPERATURES
ALOFT GET WARMER. ALL OF THESE FACTORS WILL CAUSE THE ONGOING LAKE
SNOW BANDS TO LIFT SLOWLY TO THE NORTH AND WEAKEN AS THE NIGHT WEARS
ON. HOWEVER...THERE STILL WILL BE PLENTY OF LOW LEVEL MOISTURE
WITHIN THE SNOW GROWTH AREA TO GENERATE A COUPLE MORE INCHES OF SNOW
SOUTHEAST OF THE LAKES.
ON MONDAY...THE FOCUS WILL SHIFT MORE TO THE SYNOPTIC SCALE. THE
SURFACE RIDGE WILL SLIDE OFF THE EAST COAST...WHILE A CLIPPER DIVES
SOUTHEAST ACROSS ONTARIO PROVINCE. WARM AIR ADVECTION AND A DEEPER
LAYER OF MOISTURE AHEAD OF THE CLIPPER WILL GENERATE A MORE
WIDESPREAD AREA OF LIGHT SNOW...ESPECIALLY DURING THE AFTERNOON.
THE PRESSURE GRADIENT BETWEEN THE HIGH AND APPROACHING LOW WILL
LIKELY RESULT IN RATHER WINDY CONDITIONS...ESPECIALLY NORTHEAST OF
LAKE ERIE. TEMPERATURES ON MONDAY WILL MODERATE INTO THE LOWER TO MID
30S ACROSS THE LOWER ELEVATIONS...BUT THE BRISK WINDS WILL KEEP WIND
CHILLS IN THE 20S.
LIGHT SNOW WILL CONTINUE TO IMPACT OUR AREA MONDAY NIGHT AS THE LOW
TRACKS SOUTH OF JAMES BAY INTO SOUTHERN QUEBEC.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
ON TUESDAY LOW PRESSURE WILL MOVE ACROSS ONTARIO AND QUEBEC. THIS
MAY BRING A FEW MORE LIGHT SNOW SHOWERS TO THE REGION AND THE
AIRMASS REMAINS JUST COLD ENOUGH FOR SOME LAKE ENHANCEMENT EAST AND
NORTHEAST OF BOTH LAKES.
NEXT WEDNESDAY STILL BEARS WATCHING FOR A POTENTIAL EAST COAST
STORM. THE MID LEVEL CLOSED LOW CURRENTLY STUCK OVER THE SOUTHWEST
STATES WILL EJECT EASTWARD AND REACH THE MID ATLANTIC COAST BY LATE
WEDNESDAY. AT THE SAME TIME ANOTHER SHARP NORTHERN STREAM TROUGH
WILL DIG THROUGH THE GREAT LAKES. MODEL GUIDANCE VARIES ON THE
INTERACTION AND POTENTIAL PHASING OF THESE TWO SYSTEMS.
12Z GFS IS INDICATING A SHORT SHOT OF LAKE EFFECT SNOW IN
SOUTHWESTERLY FLOW WHICH MAY IMPACT THE METRO AREAS OF
BUFFALO...ROCHESTER...AND WATERTOWN WEDNESDAY AND WEDNESDAY
NIGHT...FOLLOWED BY COLDER NORTHWEST TO NORTH WINDS ACROSS THE LAKES
AS THE COASTAL LOW DEVELOPS AND ANOTHER ROUND OF LAKE SNOW SOUTH AND
SOUTHEAST OF THE LAKES.
12Z ECMWF DEVELOPS THE COASTAL LOW CLOSER TO THE EAST COAST AND
INDICATES A SNOW EVENT FOR THE COASTAL REGION AND INLAND TO EASTERN
NEW YORK STATE DURING TUESDAY NIGHT THROUGH WEDNESDAY AFTERNOON...
THEN A WEAK LAKE RESPONSE FOLLOWED BY COLD HIGH PRESSURE ON THURSDAY.
IN EITHER CASE...AFTER AN UNSETTLED MID WEEK PERIOD...THERE WILL BE
AN INFLUX OF COLDER AIR FOR THANKSGIVING DAY AND A BIT OF A WARMING
TREND FOR THE END OF THE WEEK.
&&
.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
THROUGH NOON MOST AREAS WILL BE VFR AHEAD OF THE FRONT...WITH
PATCHY MVFR CIGS EAST OF THE LAKES.
AN ARCTIC FRONT WILL CROSS THE AREA EARLY THIS AFTERNOON WITH A
BRIEF PERIOD OF SNOW SHOWERS AND SOME LAKE ENHANCEMENT EAST OF THE
LAKES WITH BRIEF IFR. LATER THIS AFTERNOON AND TONIGHT LAKE EFFECT
SNOW SHOWERS WILL DEVELOP SOUTHEAST OF THE LAKES WITH LOCAL IFR AT
TIMES. THE TAF SITES MOST LIKELY IMPACTED BY MORE PERSISTENT SNOW
SHOWERS WILL BE KJHW AND KROC...WITH LESSER COVERAGE NEAR KBUF AND
KIAG. OVER AT KART...LAKE ENHANCED SNOW DURING THE AFTERNOON AND
EVENING WILL PRODUCE OCCASIONAL IFR...THEN EXPECT AN IMPROVEMENT TO
VFR TONIGHT AS LAKE EFFECT PUSHES WELL SOUTH OF THE AREA.
OUTLOOK...
SUNDAY...AREAS OF IFR SOUTHEAST OF THE LAKES IN LAKE EFFECT SNOW.
MONDAY THROUGH WEDNESDAY...VFR WITH A CHANCE OF SNOW SHOWERS AND
ASSOCIATED BRIEF MVFR/IFR.
&&
.MARINE...
WINDS WILL INCREASE TODAY ALONG AND BEHIND A STRONG ARCTIC COLD
FRONT. THIS WILL BRING MARGINAL GALE FORCE WINDS TO THE EAST HALF OF
LAKE ONTARIO THIS AFTERNOON AND EVENING. ELSEWHERE WINDS WILL
INCREASE TO 30 KNOTS. TONIGHT WINDS WILL BECOME NORTHWEST AND
DIMINISH A LITTLE TO AROUND 25 KNOTS. MODERATE TO STRONG
NORTHWESTERLIES WILL CONTINUE THROUGH SUNDAY.
WITH COLD AIR ENTRENCHED ACROSS THE GREAT LAKES IT WILL BE WINDY
THROUGH MUCH OF NEXT WEEK WITH SMALL CRAFT ADVISORIES ALL THE TIME
AND A FEW BRIEF OPPORTUNITIES AT GALE FORCE WINDS.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST SUNDAY FOR NYZ001>003-
011>014-020-085.
LAKE EFFECT SNOW ADVISORY UNTIL 10 PM EST THIS EVENING FOR
NYZ007-008.
LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST SUNDAY FOR NYZ004>006.
LAKE EFFECT SNOW WARNING UNTIL 7 PM EST SUNDAY FOR NYZ019.
MARINE...SMALL CRAFT ADVISORY UNTIL 1 AM EST MONDAY FOR LEZ040-041.
SMALL CRAFT ADVISORY UNTIL 4 AM EST SUNDAY FOR LEZ020.
SMALL CRAFT ADVISORY UNTIL 4 AM EST SUNDAY FOR LOZ030.
SMALL CRAFT ADVISORY UNTIL 1 AM EST MONDAY FOR LOZ042.
SMALL CRAFT ADVISORY UNTIL NOON EST TODAY FOR LOZ043>045.
GALE WARNING UNTIL 10 PM EST THIS EVENING FOR LOZ043>045-
063>065.
SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 7 PM
EST SUNDAY FOR SLZ022-024.
&&
$$
SYNOPSIS...HITCHCOCK
NEAR TERM...APFFEL/HITCHCOCK
SHORT TERM...TJP
LONG TERM...TJP
AVIATION...APFFEL/HITCHCOCK
MARINE...APFFEL/HITCHCOCK
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1203 PM EST SAT NOV 23 2013
.SYNOPSIS... A COLD FRONT WILL CONTINUE TO DROP SOUTH ACROSS THE
CAROLINAS TODAY WITH A REINFORCING COLD FRONT TO FOLLOW TONIGHT AS
COLD HIGH PRESSURE BUILDS IN FOR THE REMAINDER OF THE WEEKEND.
&&
.NEAR TERM /TODAY AND TONIGHT/...
AS OF 940 AM SATURDAY...
OVERVIEW: POTENT SHORTWAVE ENERGY OVER THE UPPER MIDWEST AT 08Z THIS
MORNING WILL DIG SOUTHEAST THROUGH THE OH VALLEY THIS AFTERNOON...
AMPLIFYING AN UPPER LEVEL TROUGH AS IT PROGRESSES TOWARD THE MID-
ATLANTIC COAST TONIGHT. IN THE LOWER LEVELS...A COLD FRONT EXTENDING
FROM CENTRAL GA NORTHEAST THROUGH CENTRAL NC AND SOUTHEAST VA AT 08Z
WILL PROGRESS SOUTHEAST TO THE COAST THIS MORNING...FOLLOWED BY A
STRONGER REINFORCING COLD FRONT THIS EVENING...THE LEADING EDGE OF
AN ARCTIC AIRMASS (1045-1050 MB SFC HIGH IN THE CENTRAL CONUS)
BUILDING INTO THE REGION OVERNIGHT. -VINCENT
AS OF 12Z THIS MORNING THE COLD FRONT WAS DRAPED ACROSS CENTRAL
NORTH CAROLINA WHERE IT WAS BEGINNING TO STALL OUT. VISIBLE
SATELLITE IMAGERY HAD SHOWN A DISTINCT BOUNDARY WITH THE TRIAD
CLEARING OUT FOR A TIME EARLIER THIS MORNING BUT SINCE THEN CLOUDS
HAVE BEGUN TO BACK BUILD OVER THE TRIANGLE AREA AND NEW CLOUD COVER
HAS ADVECTED INTO THE TRIAD FROM THE WEST. AS A RESULT...EXPECT HIGH
TEMPERATURES TODAY TO BE ABOUT WHAT THEY ARE NOW WITH MAYBE SOME
SLIGHT INCREASES TO THE CURRENT OBSERVED TEMPERATURES. AS FAR AS
PRECIPITATION GOES...IT SHOULD REMAIN LIGHT IN THE FRONTAL ZONE AND
POINTS SOUTH AND EAST WITH TOTALS A COUPLE HUNDREDTHS OF AN INCH OR
LESS. LATER THIS MORNING AND INTO THE AFTERNOON COLD AIR ADVECTION
SHOULD TAKE OVER DROPPING TEMPERATURES IN THE NORTHERN HALF OF THE
CWA WITH CLOUD COVER TO THE SOUTH KEEPING TEMPERATURES DOWN THERE AS
WELL. WITH THE ONSET OF COLD AIR ADVECTION WE SHOULD SEE A DECREASE
IN DEWPOINTS AS WELL AS AN INCREASE IN THE WIND GUSTS...UP TO 15
KNOTS OR SO AND THIS HAS ALREADY BEGUN TO OCCUR IN THE TRIAD.
FOR THIS AFTERNOON BOTH THE RAP AND THE NAM ARE DEPICTING A FAIRLY
WELL DEFINED 500 MB VORT MAX THAT WILL RUN ALONG THE FRONT AND
PROVIDE SOME EXTRA FORCING FOR SOME SPRINKLES TO LIGHT RAIN ACROSS
THE SOUTHERN HALF OF THE CWA. HAVE INCREASED POPS TO CHANCE IN THE
SOUTH AROUND 18Z AND THEN QUICKLY TAPERING OFF AFTER DARK.
THE SURFACE HIGH WILL CONTINUE TO BUILD IN FROM THE NORTHWEST
TONIGHT AND A REINFORCING DRY COLD FRONT WILL HELP SKIES CLEAR FORM
NORTH TO SOUTH. COMBINED COLD AIR ADVECTION AND CLEARING WILL HELP
TEMPERATURES DROP INTO THE MIDDLE 20S FOR LOWS IN THE TRIAD WITH
UPPER 20S TO LOW 30S ELSEWHERE.
&&
.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
AS OF 325 AM SATURDAY...
STRONG ARCTIC HIGH PRESSURE WILL CONTINUE TO BUILD INTO THE REGION
ON SUNDAY...BECOMING CENTERED OVER THE AREA SUNDAY NIGHT. WITH COLD
ADVECTION PERSISTING THROUGH MUCH OF THE DAY...1000-850 MB
THICKNESSES BETWEEN 1265-1275 METERS IN THE AFTERNOON...AND H85
TEMPS RANGING FROM -10C (S) TO -13C (N)...EXPECT TEMPERATURES TO
STRUGGLE OUT OF THE 30S IN MOST LOCATIONS...AND WILL INDICATE HIGHS
RANGING FROM JUST ABOVE FREEZING (~34F) IN THE NW TO NEAR 40F IN THE
FAR S/SE. WITH A COLD/DRY ARCTIC AIRMASS SETTLING OVERHEAD SUN
NIGHT...EXPECT OPTIMAL RADIATIONAL COOLING AND LOWS IN THE TEENS TO
LOWER 20S...COLDEST IN RURAL AND LOW-LYING AREAS. -VINCENT
&&
.LONG TERM /MONDAY THOUGH FRIDAY/...
AS OF 222 AM SATURDAY...
...A GOOD SOAKING RAIN TUE-WED...
...PRECIPITATION MAY BEGIN AS A BRIEF WINTRY MIX IN THE NW PIEDMONT
IF THE PRECIPITATION BEGINS BEFORE 12Z TUESDAY...
THE CORE OF THE ARCTIC AIR MASS WILL BE LOCATED OVER THE REGION AT
12Z MONDAY. HIGH PRESSURE WILL GRADUALLY SHIFT OFFSHORE MONDAY
NIGHT. MODELS ARE IN EXCELLENT AGREEMENT WITH THE PARENT HIGH
PRESSURE MOVING OFFSHORE MONDAY NIGHT (VERY CRITICAL TO THIS
FORECAST). THIS TO BE FOLLOWED BY A RAPID INCREASE IN MID AND UPPER
LEVEL MOISTURE MONDAY NIGHT. THEREFORE... A CONTINUED MOSTLY SUNNY
DAY IS FORECAST MONDAY WITH HIGHS 40-45. INCREASING CLOUDINESS
MONDAY NIGHT WITH LOWS 30-35.
A SIGNIFICANT MID/UPPER LEVEL LOW PRESSURE IS FORECAST TO EJECT OUT
OF TEXAS TUESDAY MORNING... THEN TRACK EAST ALONG THE GULF COAST AND
ACROSS THE SOUTHEASTERN STATES TUESDAY THROUGH WEDNESDAY. RECENT
DETERMINISTIC MODELS HAVE BEEN FORECASTING A COUPLE OF STRUNG OUT
WEAK LOW PRESSURE CENTERS TO TRACK FROM THE N-NE GULF OF MEXICO
ALONG THE CAROLINA COAST TUE-WED. THIS IS IMPORTANT IN THAT THERE
APPEARS TO BE LITTLE PHASING OF THE POLAR JET WITH THIS SOUTHERN
BRANCH SYSTEM UNTIL THE SYSTEM IS PAST OUR LATITUDE AND OFFSHORE
LATE WED... KEEPING THE SURFACE SYSTEM(S) WEAK AND STRUNG OUT
INSTEAD OF ONE STRONG LOW PRESSURE. REGARDLESS... THIS STILL APPEARS
TO BE A GOOD RAINFALL PRODUCER FOR OUR REGION. MANY AREAS HAVE HAD
LESS THAN 25 PERCENT OF THE AVERAGE RAINFALL SINCE SEPTEMBER.
AS FOR PRECIPITATION TYPE (P-TYPE)... CONFIDENCE CONTINUES HIGH IN
THAT RAIN WILL BE PREDOMINATE P-TYPE DUE TO THE RAPIDLY DEVELOPING
PROMINENT WARM NOSE ALOFT. HOWEVER IN THE WESTERN AND NORTHERN
PIEDMONT ZONES SOME LIGHT SNOW/SLEET/FREEZING RAIN MAY FALL AT THE
ONSET DEPENDING ON TIMING. IF THE PRECIPITATION DEVELOPS EARLY
ENOUGH (BEFORE 15Z)... THERE MAY BE SOME NUISANCE LIGHT SNOW/SLEET
(12Z) BEFORE A QUICK CHANGE TO LIGHT FREEZING RAIN/RAIN THEN ALL
RAIN BY 15Z. THE MAJORITY OF ENSEMBLE FORECASTS INDICATE STRONG WAA
JUST ABOVE THE BOUNDARY LAYER TAKING THE 1000/850 AND 850/700
PARTIAL THICKNESSES WELL INTO THE HISTORICALLY "ALL RAIN" CATEGORY
RATHER QUICKLY TUESDAY.
THE AMOUNT OF VERY DRY AIR IN PLACE BEFORE MOISTENING TUESDAY
MORNING APPEARS SUBSTANTIAL... WITH DEW POINTS FORECAST IN THE 15-20
RANGE AROUND 12Z IN THE PIEDMONT. PARTIALS IN THE 1295-1305 / 1550
RANGE RAPIDLY WARM WITH TIME...SUGGESTING A POSSIBLE LIGHT
FROZEN/FREEZING EVENT IN THE NW (TRACE AMOUNTS) QUICKLY CHANGING TO
RAIN. THE SURFACE WET BULB FORECASTS QUICKLY MODIFY AFTER
DAYBREAK... REACHING THE LOWER 30S BY MIDDAY AND MID 30S BY EVENING.
GIVEN THAT THERE WILL BE PLENTY OF EVAPORATION AT THE LEADING EDGE
OF THE PRECIPITATION SHIELD... SUGGESTING THAT ANYTHING THAT REACHES
THE SURFACE WILL BE VERY LIGHT THROUGH THE CRITICAL PERIOD (10Z-
13Z). THEREFORE... WE WILL MAINTAIN THE "ALL RAIN" FORECAST FOR NOW
GIVEN THE UNCERTAINTY OF TIMING OF ARRIVAL OF THE PRECIPITATION
NOTING THAT ANYTHING OTHER THAN RAIN WOULD MOST LIKELY BE OF
NUISANCE.
THE LATEST OPERATIONAL EUROPEAN CONTINUES TO BE QUICK AND ROBUST
WITH DEVELOPING/SPREADING PRECIPITATION NE ACROSS WESTERN NC BETWEEN
06Z AND 12Z TUESDAY. EVEN THE LATEST NAM A FEW ENSEMBLE MEMBERS ARE
THIS AGGRESSIVE... WITH AS MUCH AS 0.25 OF QPF BY 12Z IN THE HKY TO
INT AREAS. IF THIS WERE TO OCCUR... THE SOUNDINGS INDICATE RAPIDLY
WARMING MID LEVELS BETWEEN 06Z/12Z TUESDAY... BECOMING A PROMINENT
WARM NOSE ALOFT AS EARLY AS 18Z. THE NEAR SURFACE LAYER MAY BE VERY
CLOSE TO OR SLIGHTLY BELOW FREEZING FOR A COUPLE OF HOURS CENTERED
AROUND 12Z. THEREFORE... THE CURRENT WORST CASE SCENARIO WOULD BE
FOR SOME LIGHT SNOW AND SLEET TO DEVELOP BEFORE SUNRISE... QUICKLY
BECOMING LIGHT FREEZING RAIN AROUND 12Z... THEN RAIN BY 15Z AS
WARMING ALOFT AND HEAVIER RAIN WARMS THE COLUMN FROM THE TOP DOWN.
THIS WOULD BE THE ONE CAVEAT... IF THE LATEST EC AND SOME ENSEMBLE
MEMBERS PROVE CORRECT IN THE QUICKER ARRIVAL OF LIGHT PRECIPITATION
BEFORE OR AROUND DAYBREAK... THEN MORE IN THE WAY OF SOME LIGHT
FREEZING RAIN OR EVEN SOME BRIEF LIGHT FROZEN HYDROMETERS MAY FALL
IN THE NW.
SENSIBLE WEATHER THEN... PREDOMINATELY COLD RAIN IS EXPECTED TUESDAY
INTO TUESDAY NIGHT... WITH PERIODS OF RAIN EVEN INTO WEDNESDAY AS
THE MID/UPPER LOW FOLLOW... AND TRACK ACROSS THE REGION WEDNESDAY.
PARTIAL THICKNESSES SUPPORT A BRIEF MIX OR CHANGE TO LIGHT SNOW
(LITTLE ACCUMULATION EXPECTED CURRENTLY) BEFORE ENDING IN THE NW AND
N PIEDMONT BETWEEN 18Z AND 23Z WED.
IF THE 1-2 INCH QPF OF RAINFALL WORKS OUT BEFORE HAND... AND WITH
TEMPS WELL ABOVE 35 WED AFTERNOON... IT WOULD HAVE TO SNOW HEAVILY
TO ACCUMULATE. THIS IS NOT ANTICIPATED AT THIS TIME.
CLEARING IS EXPECTED WEDNESDAY NIGHT AND DRY COLD CONDITIONS CAN BE
EXPECTED THANKSGIVING DAY AND FRIDAY. LOWS IN THE LOWER TO MID 20S.
HIGHS IN THE LOWER TO MID 40S (15-20 DEGREES BELOW NORMAL).
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
AS OF 1200 PM SATURDAY...
24 HOUR TAF PERIOD: VFR CONDITIONS SHOULD PREVAIL AT MOST LOCATIONS
THROUGH THE TAF PERIOD WITH THE EXCEPTION OF KFAY WHICH MIGHT SEE A
BRIEF DROP TO MVFR THIS AFTERNOON WITH SOME LIGHT RAIN ASSOCIATED
WITH A SHORTWAVE MOVING THROUGH THE CHARLOTTE AREA AT THIS TIME.
OTHERWISE NORTHWESTERLY FLOW THIS AFTERNOON AT 5-10 KNOTS WITH THE
OCCASIONAL GUST TO 15 KNOTS THROUGH SUNSET. OVERNIGHT TONIGHT A
REINFORCING COLD FRONT WILL COME THROUGH AND ALTHOUGH IT WILL BE
DRY...THE WINDS WILL PICK UP CONSIDERABLY AFTER 4Z IN THE TRIAD AND
AFTER 6Z ELSEWHERE. WINDS WILL BE NORTHERLY. EXPECT 10-15 KNOTS
SUSTAINED GUSTING UPWARDS OF 25 KTS FROM 6Z THROUGH THE END OF THE
TAF PERIOD. EXPECT SKIES TO CLEAR OUT ONCE THE SECONDARY FRONT
PASSES THROUGH AS THE SURFACE HIGH BUILDS INTO THE AREA.
LONG TERM: A FAIRLY POTENT STORM SYSTEM WILL MOVE INTO THE AREA FROM
THE SOUTHWEST ON TUESDAY NIGHT INTO WEDNESDAY...FOLLOWED BY A
SECONDARY LOW WEDNESDAY NIGHT INTO THURSDAY. BOTH LOWS ARE PROGGED
TO TRACK OFF THE COAST AT THIS TIME. WHILE SEVERE WX SHOULD NOT BE A
THREAT...AN EXTENDED PERIOD OF MODERATE RAIN WITH ADVERSE AVIATION
CONDITIONS WILL BE PROBABLE.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...ELLIS
NEAR TERM...VINCENT/ELLIS
SHORT TERM...VINCENT
LONG TERM...BADGETT
AVIATION...ELLIS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
948 AM EST SAT NOV 23 2013
.SYNOPSIS... A COLD FRONT WILL CONTINUE TO DROP SOUTH ACROSS THE
CAROLINAS TODAY WITH A REINFORCING COLD FRONT TO FOLLOW TONIGHT AS
COLD HIGH PRESSURE BUILDS IN FOR THE REMAINDER OF THE WEEKEND.
&&
.NEAR TERM /TODAY AND TONIGHT/...
AS OF 940 AM SATURDAY...
OVERVIEW: POTENT SHORTWAVE ENERGY OVER THE UPPER MIDWEST AT 08Z THIS
MORNING WILL DIG SOUTHEAST THROUGH THE OH VALLEY THIS AFTERNOON...
AMPLIFYING AN UPPER LEVEL TROUGH AS IT PROGRESSES TOWARD THE MID-
ATLANTIC COAST TONIGHT. IN THE LOWER LEVELS...A COLD FRONT EXTENDING
FROM CENTRAL GA NORTHEAST THROUGH CENTRAL NC AND SOUTHEAST VA AT 08Z
WILL PROGRESS SOUTHEAST TO THE COAST THIS MORNING...FOLLOWED BY A
STRONGER REINFORCING COLD FRONT THIS EVENING...THE LEADING EDGE OF
AN ARCTIC AIRMASS (1045-1050 MB SFC HIGH IN THE CENTRAL CONUS)
BUILDING INTO THE REGION OVERNIGHT. -VINCENT
AS OF 12Z THIS MORNING THE COLD FRONT WAS DRAPED ACROSS CENTRAL
NORTH CAROLINA WHERE IT WAS BEGINNING TO STALL OUT. VISIBLE
SATELLITE IMAGERY HAD SHOWN A DISTINCT BOUNDARY WITH THE TRIAD
CLEARING OUT FOR A TIME EARLIER THIS MORNING BUT SINCE THEN CLOUDS
HAVE BEGUN TO BACK BUILD OVER THE TRIANGLE AREA AND NEW CLOUD COVER
HAS ADVECTED INTO THE TRIAD FROM THE WEST. AS A RESULT...EXPECT HIGH
TEMPERATURES TODAY TO BE ABOUT WHAT THEY ARE NOW WITH MAYBE SOME
SLIGHT INCREASES TO THE CURRENT OBSERVED TEMPERATURES. AS FAR AS
PRECIPITATION GOES...IT SHOULD REMAIN LIGHT IN THE FRONTAL ZONE AND
POINTS SOUTH AND EAST WITH TOTALS A COUPLE HUNDREDTHS OF AN INCH OR
LESS. LATER THIS MORNING AND INTO THE AFTERNOON COLD AIR ADVECTION
SHOULD TAKE OVER DROPPING TEMPERATURES IN THE NORTHERN HALF OF THE
CWA WITH CLOUD COVER TO THE SOUTH KEEPING TEMPERATURES DOWN THERE AS
WELL. WITH THE ONSET OF COLD AIR ADVECTION WE SHOULD SEE A DECREASE
IN DEWPOINTS AS WELL AS AN INCREASE IN THE WIND GUSTS...UP TO 15
KNOTS OR SO AND THIS HAS ALREADY BEGUN TO OCCUR IN THE TRIAD.
FOR THIS AFTERNOON BOTH THE RAP AND THE NAM ARE DEPICTING A FAIRLY
WELL DEFINED 500 MB VORT MAX THAT WILL RUN ALONG THE FRONT AND
PROVIDE SOME EXTRA FORCING FOR SOME SPRINKLES TO LIGHT RAIN ACROSS
THE SOUTHERN HALF OF THE CWA. HAVE INCREASED POPS TO CHANCE IN THE
SOUTH AROUND 18Z AND THEN QUICKLY TAPERING OFF AFTER DARK.
THE SURFACE HIGH WILL CONTINUE TO BUILD IN FROM THE NORTHWEST
TONIGHT AND A REINFORCING DRY COLD FRONT WILL HELP SKIES CLEAR FORM
NORTH TO SOUTH. COMBINED COLD AIR ADVECTION AND CLEARING WILL HELP
TEMPERATURES DROP INTO THE MIDDLE 20S FOR LOWS IN THE TRIAD WITH
UPPER 20S TO LOW 30S ELSEWHERE.
&&
.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
AS OF 325 AM SATURDAY...
STRONG ARCTIC HIGH PRESSURE WILL CONTINUE TO BUILD INTO THE REGION
ON SUNDAY...BECOMING CENTERED OVER THE AREA SUNDAY NIGHT. WITH COLD
ADVECTION PERSISTING THROUGH MUCH OF THE DAY...1000-850 MB
THICKNESSES BETWEEN 1265-1275 METERS IN THE AFTERNOON...AND H85
TEMPS RANGING FROM -10C (S) TO -13C (N)...EXPECT TEMPERATURES TO
STRUGGLE OUT OF THE 30S IN MOST LOCATIONS...AND WILL INDICATE HIGHS
RANGING FROM JUST ABOVE FREEZING (~34F) IN THE NW TO NEAR 40F IN THE
FAR S/SE. WITH A COLD/DRY ARCTIC AIRMASS SETTLING OVERHEAD SUN
NIGHT...EXPECT OPTIMAL RADIATIONAL COOLING AND LOWS IN THE TEENS TO
LOWER 20S...COLDEST IN RURAL AND LOW-LYING AREAS. -VINCENT
&&
.LONG TERM /MONDAY THOUGH FRIDAY/...
AS OF 222 AM SATURDAY...
...A GOOD SOAKING RAIN TUE-WED...
...PRECIPITATION MAY BEGIN AS A BRIEF WINTRY MIX IN THE NW PIEDMONT
IF THE PRECIPITATION BEGINS BEFORE 12Z TUESDAY...
THE CORE OF THE ARCTIC AIR MASS WILL BE LOCATED OVER THE REGION AT
12Z MONDAY. HIGH PRESSURE WILL GRADUALLY SHIFT OFFSHORE MONDAY
NIGHT. MODELS ARE IN EXCELLENT AGREEMENT WITH THE PARENT HIGH
PRESSURE MOVING OFFSHORE MONDAY NIGHT (VERY CRITICAL TO THIS
FORECAST). THIS TO BE FOLLOWED BY A RAPID INCREASE IN MID AND UPPER
LEVEL MOISTURE MONDAY NIGHT. THEREFORE... A CONTINUED MOSTLY SUNNY
DAY IS FORECAST MONDAY WITH HIGHS 40-45. INCREASING CLOUDINESS
MONDAY NIGHT WITH LOWS 30-35.
A SIGNIFICANT MID/UPPER LEVEL LOW PRESSURE IS FORECAST TO EJECT OUT
OF TEXAS TUESDAY MORNING... THEN TRACK EAST ALONG THE GULF COAST AND
ACROSS THE SOUTHEASTERN STATES TUESDAY THROUGH WEDNESDAY. RECENT
DETERMINISTIC MODELS HAVE BEEN FORECASTING A COUPLE OF STRUNG OUT
WEAK LOW PRESSURE CENTERS TO TRACK FROM THE N-NE GULF OF MEXICO
ALONG THE CAROLINA COAST TUE-WED. THIS IS IMPORTANT IN THAT THERE
APPEARS TO BE LITTLE PHASING OF THE POLAR JET WITH THIS SOUTHERN
BRANCH SYSTEM UNTIL THE SYSTEM IS PAST OUR LATITUDE AND OFFSHORE
LATE WED... KEEPING THE SURFACE SYSTEM(S) WEAK AND STRUNG OUT
INSTEAD OF ONE STRONG LOW PRESSURE. REGARDLESS... THIS STILL APPEARS
TO BE A GOOD RAINFALL PRODUCER FOR OUR REGION. MANY AREAS HAVE HAD
LESS THAN 25 PERCENT OF THE AVERAGE RAINFALL SINCE SEPTEMBER.
AS FOR PRECIPITATION TYPE (P-TYPE)... CONFIDENCE CONTINUES HIGH IN
THAT RAIN WILL BE PREDOMINATE P-TYPE DUE TO THE RAPIDLY DEVELOPING
PROMINENT WARM NOSE ALOFT. HOWEVER IN THE WESTERN AND NORTHERN
PIEDMONT ZONES SOME LIGHT SNOW/SLEET/FREEZING RAIN MAY FALL AT THE
ONSET DEPENDING ON TIMING. IF THE PRECIPITATION DEVELOPS EARLY
ENOUGH (BEFORE 15Z)... THERE MAY BE SOME NUISANCE LIGHT SNOW/SLEET
(12Z) BEFORE A QUICK CHANGE TO LIGHT FREEZING RAIN/RAIN THEN ALL
RAIN BY 15Z. THE MAJORITY OF ENSEMBLE FORECASTS INDICATE STRONG WAA
JUST ABOVE THE BOUNDARY LAYER TAKING THE 1000/850 AND 850/700
PARTIAL THICKNESSES WELL INTO THE HISTORICALLY "ALL RAIN" CATEGORY
RATHER QUICKLY TUESDAY.
THE AMOUNT OF VERY DRY AIR IN PLACE BEFORE MOISTENING TUESDAY
MORNING APPEARS SUBSTANTIAL... WITH DEW POINTS FORECAST IN THE 15-20
RANGE AROUND 12Z IN THE PIEDMONT. PARTIALS IN THE 1295-1305 / 1550
RANGE RAPIDLY WARM WITH TIME...SUGGESTING A POSSIBLE LIGHT
FROZEN/FREEZING EVENT IN THE NW (TRACE AMOUNTS) QUICKLY CHANGING TO
RAIN. THE SURFACE WET BULB FORECASTS QUICKLY MODIFY AFTER
DAYBREAK... REACHING THE LOWER 30S BY MIDDAY AND MID 30S BY EVENING.
GIVEN THAT THERE WILL BE PLENTY OF EVAPORATION AT THE LEADING EDGE
OF THE PRECIPITATION SHIELD... SUGGESTING THAT ANYTHING THAT REACHES
THE SURFACE WILL BE VERY LIGHT THROUGH THE CRITICAL PERIOD (10Z-
13Z). THEREFORE... WE WILL MAINTAIN THE "ALL RAIN" FORECAST FOR NOW
GIVEN THE UNCERTAINTY OF TIMING OF ARRIVAL OF THE PRECIPITATION
NOTING THAT ANYTHING OTHER THAN RAIN WOULD MOST LIKELY BE OF
NUISANCE.
THE LATEST OPERATIONAL EUROPEAN CONTINUES TO BE QUICK AND ROBUST
WITH DEVELOPING/SPREADING PRECIPITATION NE ACROSS WESTERN NC BETWEEN
06Z AND 12Z TUESDAY. EVEN THE LATEST NAM A FEW ENSEMBLE MEMBERS ARE
THIS AGGRESSIVE... WITH AS MUCH AS 0.25 OF QPF BY 12Z IN THE HKY TO
INT AREAS. IF THIS WERE TO OCCUR... THE SOUNDINGS INDICATE RAPIDLY
WARMING MID LEVELS BETWEEN 06Z/12Z TUESDAY... BECOMING A PROMINENT
WARM NOSE ALOFT AS EARLY AS 18Z. THE NEAR SURFACE LAYER MAY BE VERY
CLOSE TO OR SLIGHTLY BELOW FREEZING FOR A COUPLE OF HOURS CENTERED
AROUND 12Z. THEREFORE... THE CURRENT WORST CASE SCENARIO WOULD BE
FOR SOME LIGHT SNOW AND SLEET TO DEVELOP BEFORE SUNRISE... QUICKLY
BECOMING LIGHT FREEZING RAIN AROUND 12Z... THEN RAIN BY 15Z AS
WARMING ALOFT AND HEAVIER RAIN WARMS THE COLUMN FROM THE TOP DOWN.
THIS WOULD BE THE ONE CAVEAT... IF THE LATEST EC AND SOME ENSEMBLE
MEMBERS PROVE CORRECT IN THE QUICKER ARRIVAL OF LIGHT PRECIPITATION
BEFORE OR AROUND DAYBREAK... THEN MORE IN THE WAY OF SOME LIGHT
FREEZING RAIN OR EVEN SOME BRIEF LIGHT FROZEN HYDROMETERS MAY FALL
IN THE NW.
SENSIBLE WEATHER THEN... PREDOMINATELY COLD RAIN IS EXPECTED TUESDAY
INTO TUESDAY NIGHT... WITH PERIODS OF RAIN EVEN INTO WEDNESDAY AS
THE MID/UPPER LOW FOLLOW... AND TRACK ACROSS THE REGION WEDNESDAY.
PARTIAL THICKNESSES SUPPORT A BRIEF MIX OR CHANGE TO LIGHT SNOW
(LITTLE ACCUMULATION EXPECTED CURRENTLY) BEFORE ENDING IN THE NW AND
N PIEDMONT BETWEEN 18Z AND 23Z WED.
IF THE 1-2 INCH QPF OF RAINFALL WORKS OUT BEFORE HAND... AND WITH
TEMPS WELL ABOVE 35 WED AFTERNOON... IT WOULD HAVE TO SNOW HEAVILY
TO ACCUMULATE. THIS IS NOT ANTICIPATED AT THIS TIME.
CLEARING IS EXPECTED WEDNESDAY NIGHT AND DRY COLD CONDITIONS CAN BE
EXPECTED THANKSGIVING DAY AND FRIDAY. LOWS IN THE LOWER TO MID 20S.
HIGHS IN THE LOWER TO MID 40S (15-20 DEGREES BELOW NORMAL).
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
AS OF 645 AM SATURDAY...
24-HR TAF PERIOD: WINDS WILL SHIFT TO THE NW/NNW AT 8-12 KT WITH
SPORADIC GUSTS UP TO 15-20 KT POSSIBLE FOR SEVERAL HOURS AFTER A
COLD FROPA THIS MORNING...WITH WINDS EVENTUALLY DECREASING TO 5-10
KT LATER THIS AFTERNOON. A SECONDARY AND STRONGER ARCTIC COLD
FRONTAL PASSAGE WILL OCCUR THIS EVE/TONIGHT. DUE TO STRONG PRESSURE
RISES BEHIND THE ARCTIC FRONT...EXPECT NW/NNW WINDS TO RAPIDLY
INCREASE AND BECOME SUSTAINED AT 13-17 KT WITH GUSTS UP TO 25 KT
LATE TONIGHT THROUGH SUNDAY MORNING. AT THIS TIME...EXPECT VFR
CONDITIONS TO PREVAIL ASIDE FROM ISOLD AREAS OF FOG AND MVFR STRATUS
FOR A FEW HOURS THIS MORNING...PERHAPS AFFECTING THE FAY TERMINAL
THROUGH 12-14Z.
LOOKING AHEAD: VFR CONDITIONS ASSOCIATED WITH ARCTIC HIGH PRESSURE
WILL PREVAIL TONIGHT THROUGH MONDAY. A SIGNIFICANT STORM SYSTEM WILL
DEVELOP ALONG THE GULF COAST MON/MON NIGHT...THEN TRACK NORTHEAST
ALONG THE CAROLINA COAST ON TUE/WED. EXPECT WIDESPREAD ADVERSE
AVIATION CONDITIONS MON NIGHT THROUGH WED. -VINCENT
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...VINCENT/ELLIS
SHORT TERM...VINCENT
LONG TERM...BADGETT
AVIATION...VINCENT
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
633 AM EST SAT NOV 23 2013
.SYNOPSIS...
A STRONG ARCTIC COLD FRONT WILL CROSS THE AREA LATER THIS MORNING
FOLLOWED BY THE COLDEST TEMPERATURES OF THE SEASON. LOW PRESSURE
WILL EMERGE FROM THE NORTHERN GULF OF MEXICO BRINGING A SIGNIFICANT
RAIN EVENT FOR THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM SATURDAY...AN ARCTIC COLD FRONT CURRENTLY EXTENDING FROM
CENTRAL NORTH CAROLINA INTO THE UPSTATE OF SOUTH CAROLINA IS
EXPECTED TO MOVE SOUTHEAST...CROSSING THROUGH THE EASTERN CAROLINAS
LATE THIS MORNING. THERE ARE STILL SOME TIMING DIFFERENCES WITH THIS
FRONT: THE 06Z NAM AND 06Z GFS ARE TOO FAST BUT THE 10Z RUC HAS A
GOOD HANDLE ON ITS CURRENT AND FORECAST POSITIONS OUT THROUGH 18Z.
AS IS TYPICAL WITH A MORNING COLD FRONTAL PASSAGE...MOS HIGHS SHOULD
BE SEVERAL DEGREES TOO COOL AS THEY RESOLVE A TOO-WIDE/BLURRED
FRONTAL ZONE RATHER THAN THE TIGHT TEMPERATURE GRADIENT THAT
ACTUALLY EXISTS. MY FORECAST HIGHS ARE 2-3 DEGREES ABOVE MOS
(63-68...WARMEST NEAR GEORGETOWN) ALTHOUGH THESE READINGS SHOULD
OCCUR ONLY BRIEFLY AT THE TIME OF FRONTAL PASSAGE WITH FALLING
TEMPERATURES EXPECTED THROUGHOUT THE AFTERNOON.
RADAR COMPOSITES REVEAL BAND OF LIGHT SHOWERY RAIN ACROSS THE
EASTERN CAROLINAS EXTENDING BACK TO THE SAVANNAH RIVER SOUTH OF
AUGUSTA. THIS APPEARS TO BE ASSOCIATED WITH WEAK ISENTROPIC LIFT
WITHIN A MID-LAYER CLOUD DECK 7000-12000 FT AGL. MODELS SHOW
ISENTROPIC LIFT HAVING ITS GREATEST MAGNITUDE (AND THAT`S NOT SAYING
MUCH) BETWEEN NOW AND NOON...WITH NEUTRAL TO ISENTROPIC DOWNGLIDE
CONDITIONS DEVELOPING FROM NORTH TO SOUTH. MY QPF NUMBERS ARE LESS
THAN ONE TENTH OF AN INCH EVERYWHERE. CLOUDS WILL PROBABLY NOT BREAK
IN ANY SUBSTANTIAL SENSE DURING THE DAY...AND THE LACK OF INSOLATION
WILL NOT BE ABLE TO OFFSET STRENGTHENING COLD ADVECTION DURING THE
AFTERNOON.
FOR TONIGHT HIGH PRESSURE OVER THE CENTRAL PLAINS WILL SURGE
EASTWARD AS A SHORTWAVE EMBEDDED IN THE NORTHEASTERN U.S. TROUGH
SWINGS THROUGH VIRGINIA. THIS WILL LEAD TO THE REAL ARCTIC SURGE OF
THIS EVENT DEVELOPING AROUND OR JUST BEFORE MIDNIGHT. 850 MB
TEMPERATURES WILL FALL FROM AROUND +6C THIS EVENING TO -3C BY
DAYBREAK SUNDAY...AS WINDS AT THE TOP OF THE WELL-MIXED BOUNDARY
LAYER WINDS INCREASE TO 20-30 KNOTS. THE TEMPERATURE FORECAST
TONIGHT IS ACTUALLY QUITE TRICKY AS STRONG WINDS AND GOOD MIXING CAN
SOMETIMES CREATE A NIGHTTIME DEEP DRY-ADIABATIC PROFILE TYPICAL OF
DAYTIME CONDITIONS...WITH LOW TEMPERATURES ENDING UP MUCH WARMER
THAN ONE WOULD THINK POSSIBLE GIVEN THE AIRMASS. MY FORECAST LOWS
ARE A BIT ABOVE MOS GUIDANCE AND RANGE FROM NEAR FREEZING FROM
LUMBERTON TO DARLINGTON...TO 35-38 AT THE COAST.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 3 AM SATURDAY...COLD AND DRY ARCTIC HIGH BUILDS IN SUNDAY WITH
TEMPERATURES FALLING SHORT OF 50 DURING THE DAY. SURFACE RIDGE AXIS
SHIFTS CLOSE TO THE REGION SUN NIGHT...ENDING COLD ADVECTION BUT
PUTTING RADIATIONAL COOLING IN PLAY. DEEP DRY AIR...LIGHT
WINDS...AND UNSEASONABLY COLD AIR IN PLACE WILL RESULT IN LOWS IN
THE LOW TO MID 20S IN MANY LOCATIONS WITH ISOLATED UPPER TEENS
POSSIBLE INLAND.
WHILE SOME AIR MASS MODIFICATION IS EXPECTED ON MON VERY LOW
STARTING TEMPS COMBINED WITH NORTHEAST FLOW WILL AGAIN KEEP HIGHS
WELL BELOW CLIMO. INCREASING HIGH CLOUD MON AFTERNOON WILL LIMIT
INSOLATION...FURTHER HINDERING TEMP RECOVERY. CLOUDS START TO LOWER
MON NIGHT AS WEAK ISENTROPIC LIFT IS ENHANCED BY DEVELOPMENT OF WEAK
COASTAL TROUGH MON NIGHT. GIVEN THE DEPTH OF THE DRY AIR AND THE
PROPENSITY OF GUIDANCE TO UNDERESTIMATE THE DRY AIR AND THUS
INTRODUCE POP A LITTLE TOO EARLY DO NOT PLAN MAJOR CHANGES TO
INHERITED PRECIP CHANCES MON NIGHT. INCREASING CLOUD COVER WILL HELP
KEEPS MON NIGHT LOWS SIGNIFICANTLY WARMER THAN SUN NIGHT AND MORE
IMPORTANTLY ABOVE FREEZING.
AT THIS POINT IT DOES NOT APPEAR THE MONDAY MORNING RECORD LOWS WILL
BE IN PLAY.
RECORD LOWS FOR NOVEMBER 25 AND THE NORMALS:
--------------------------------------------
ILM - 20 - 1970 NORMAL - 43
FLO - 17 - 1950 NORMAL - 41
CRE - 17 - 1950 NORMAL - 44
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 3 AM SATURDAY...PERIOD BEGINS WITH A SOUTHERN STREAM SYSTEM
ALREADY AFFECTING THE REGION. ISENTROPIC LIFT WILL TAP INTO DEEP
MOISTURE SPREADING OVER THE AREA AHEAD OF THE GULF COAST SYSTEM ON
TUE. THIS WILL LEAD TO RAIN WITH INTENSITY GRADUALLY INCREASING
THROUGHOUT THE DAY. AT THIS POINT THE MEDIUM RANGE SOLUTIONS DIVERGE
SOMEWHAT. DISTANCE WISE THE TRACKS ARE NOT FAR APART...BUT AS IS
USUALLY THE CASE FOR THE COASTAL CAROLINAS A SMALL DIFFERENCE IN THE
TRACK COULD LEAD TO HUGE DIFFERENCES IN THE FORECAST. WHAT IS KNOWN
IS A POTENT STORM IS LIKELY TO IMPACT THE REGION WITH HEAVY RAIN AND
GUSTY WINDS LATE TUE NIGHT AND WED. THE NATURE OF THE
RAIN...STRATIFORM AS OPPOSED TO MORE CONVECTIVE AND HIGH/LOW
TEMPERATURES ARE WHAT REMAIN UNCERTAIN. AN INLAND TRACK WOULD LEAD
TO WARMER TEMPERATURES BUT ALSO OPEN UP THE POSSIBILITY OF SEVERE
WEATHER. THE INHERITED FORECAST LIES IN THE MIDDLE OF THE GUIDANCE
ENVELOPE AND REMAINS IN GOOD AGREEMENT WITH THE GFS ENSEMBLES.
THEREFORE WILL NOT MAKE MANY CHANGES AT THIS TIME.
SURFACE HIGH BUILDS IN BEHIND THE EXITING SYSTEM BUT THE MID LEVEL
PATTERN REMAINS MORE PROGRESSIVE WHICH KEEPS COLDEST AIR NORTH OF
THE AREA. COLD ADVECTION THU INTO FRI WILL HOLD TEMPERATURES BELOW
CLIMO BUT NOT SEVERAL CATEGORIES BELOW.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
AS OF 12Z...IFR/LIFR IS OCCURRING GENERALLY BENEATH AND AHEAD OF AN
E-W AREA OF LIGHT RAIN THIS MORNING. AS A COLD FRONT MOVES SOUTH
THIS MORNING EXPECT LIFR/IFR CONDITIONS TO SHIFT N-S WITH
IMPROVEMENT TEMPORARILY TO VFR IN THE WAKE OF THE FRONT.
MODELS SUGGEST COPIOUS AMOUNTS OF MOISTURE REMAINING BEHIND THE
FRONT WITH AN APPROACHING UPPER IMPULSE. CONFIDENCE IS HIGH MVFR
CIGS WILL REDEVELOP LATER THIS MORNING AT ALL TERMINALS ALTHOUGH
CONFIDENCE IN TIMING IS LOW. EXPECT MVFR CEILINGS TO PERSIST
THROUGH THE AFTERNOON WITH LINGERING -RA. BY LATE AFTERNOON MVFR
SHOULD IMPROVE TO VFR AT KFLO/KMYR...WITH IMPROVEMENT TO VFR IN THE
EARLY EVENING AT THE COASTAL TERMINALS. VFR EXPECTED THROUGH THE
REMAINDER OF THE EVENING AND OVERNIGHT AS NORTH WINDS WINDS INCREASE
AND SIGNIFICANT DRYING OF THE LOW LEVELS OCCUR.
EXTENDED OUTLOOK...VFR WITH BREEZY CONDITIONS EXPECTED ON SUNDAY.
VFR EXPECTED ON MONDAY...WITH LOW PRESSURE BRINGING RAIN
TUESDAY AND WEDNESDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM SATURDAY...BIG CHANGES ARE COMING OVER THE NEXT 12-24
HOURS AS AN ARCTIC COLD FRONT MOVES ACROSS THE AREA. THE FRONT
ITSELF WILL MOVE ACROSS THE COASTAL WATERS LATE THIS MORNING...
SHIFTING OUR SOUTHWEST WINDS AROUND TO THE NORTH BUT WITHOUT ANY
IMMEDIATE INCREASE IN SPEED. THAT WILL WAIT UNTIL THIS EVENING
WHEN HIGH PRESSURE OVER THE CENTRAL PLAINS SURGES EAST AND BEGINS
TO PUSH VERY CHILLY AIR OFFSHORE. NORTH WINDS SHOULD INCREASE TO
25-30 KNOTS AFTER MIDNIGHT. MODELS SHOW WINDS AT 1000-1500 FT
ABOVE GROUND LEVEL REACHING 35 KNOTS...AND FOR THIS REASON A GALE
WATCH HAS BEEN ISSUED FOR THE POTENTIAL THESE WINDS WILL MIX DOWN
TO THE OCEAN SURFACE IN GUSTS LATE TONIGHT. THE COLD AIR GALE
EVENT WE HAD EARLIER THIS MONTH FEATURED WINDS ABOUT 5 KNOTS
STRONGER AT 1000-1500 FT ALTITUDE THAN WHAT IS EXPECTED
TONIGHT...SO IT IS NOT GUARANTEED WE WILL SEE GALE-FORCE GUSTS
ACTUALLY MEASURED AT THE GROUND/OCEAN SURFACE.
SEAS CURRENTLY ARE 4 FT OUT AT THE FRYING PAN SHOALS BUOY AND 2 FT
AT THE BUOY SOUTH OF THE MOUTH OF THE CAPE FEAR RIVER. SEAS SHOULD
NOT CHANGE APPRECIABLY UNTIL LATE THIS EVENING...BUT WILL REALLY
START TO BUILD AFTER MIDNIGHT IN RESPONSE TO THE INCREASING WIND
SPEEDS. DOMINANT WAVE PERIODS CURRENTLY AROUND 8 SECONDS SHOULD
SHORTLY CONSIDERABLY ONCE THE WINDS START CRANKING AFTER MIDNIGHT.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 3 AM SATURDAY...STRONG NORTHERLY FLOW CONTINUES SUN WITH SOLID
SCA CONDITIONS FOR AT LEAST THE FIRST HALF OF THE DAY. COLD
ADVECTION AND PRESSURE GRADIENT START TO WEAKEN LATER IN THE DAY
WITH WINDS DROPPING UNDER 20 KT IN THE EVENING. WINDS VEER TO
NORTHEAST SUN NIGHT AND MON AS CENTER OF SURFACE HIGH MOVES OVER
EASTERN NORTH CAROLINA. WEAK COASTAL TROUGH STARTS TO DEVELOP LATER
MON AND MON NIGHT AS SURFACE HIGH BECOMES ELONGATED TO THE
NORTHEAST. NEARSHORE WINDS WILL REMAIN NORTHEAST BUT CLOSER TO 20 NM
VARIABLE OR EVEN SOUTHEAST WINDS MAY DEVELOP BEFORE THE END OF THE
PERIOD. GRADIENT REMAINS WEAK IN THE VICINITY OF THE TROUGH WHICH
WILL KEEP WIND SPEEDS CLOSER TO 10 KT MON NIGHT. SEAS 4 TO 7 FT TO
START THE PERIOD FALL TO 3 TO 5 FT SUN NIGHT AND CONTINUE TO DROP AS
WINDS VEER AND WEAKEN. BY THE END OF THE PERIOD SEAS WILL BE 2 TO 3
FT.
LONG TERM /TUESDAY THROUGH WEDNESDAY/...
AS OF 3 AM SATURDAY...LARGE AMOUNT OF UNCERTAINTY FOR THE PERIOD AS
FAR AS WIND DIRECTION IS CONCERNED. THINK SCA EVENT IS IN THE WORKS
TUE NIGHT OR WED AS STRENGTHENING LOW PRESSURE SYSTEM EMERGING FROM
THE NORTHERN GULF OF MEXICO TRAVELS UP THE EAST COAST. THE TRACK OF
THE LOW REMAINS THE STICKING POINT AND WILL DETERMINE WIND
DIRECTION. CONFIDENT STRONG EAST TO SOUTHEAST FLOW WILL DEVELOP ON
TUE BUT FROM THERE CONFIDENCE DROPS. AT THIS POINT THE FAVORED
SOLUTION IS A TRACK JUST INLAND OF THE COAST WHICH LEADS TO STRONG
SOUTHERLY FLOW BECOMING SOUTHWEST LATE TUE NIGHT. SOUTHWEST WINDS
VEER TO NORTHWEST ON WED AS THE COLD FRONT PUSHES OFF THE COAST AND
HIGH PRESSURE STARTS TO BUILD IN. THE ELEVATED WIND SPEEDS COMBINED
WITH THE VARYING DIRECTIONS WILL RESULT IN A VERY CHAOTIC SEA STATE
FOR MUCH OF THE PERIOD. SEAS BUILD TUE INTO TUE NIGHT...REACHING 5
TO 8 FT AT THEIR ZENITH...THEN SLOWLY SUBSIDING DURING WED AS
OFFSHORE FLOW DEVELOPS AND INCREASES.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...GALE WATCH FROM LATE TONIGHT THROUGH SUNDAY MORNING FOR AMZ250-
252-254-256.
&&
$$
NEAR TERM...TRA
SHORT TERM...III
LONG TERM...III
AVIATION...MRR
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
324 AM EST SAT NOV 23 2013
.SYNOPSIS...
A STRONG ARCTIC COLD FRONT WILL CROSS THE AREA LATER THIS MORNING
FOLLOWED BY THE COLDEST TEMPERATURES OF THE SEASON. LOW PRESSURE
WILL EMERGE FROM THE NORTHERN GULF OF MEXICO BRINGING A SIGNIFICANT
RAIN EVENT FOR THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 3 AM SATURDAY...AN ARCTIC COLD FRONT CURRENTLY EXTENDING
FROM SOUTHEASTERN VIRGINIA INTO THE NC FOOTHILLS IS EXPECTED TO
MOVE SOUTHEAST...CROSSING THROUGH THE EASTERN CAROLINAS LATE THIS
MORNING. THERE ARE MINOR TIMING DIFFERENCES WITH THIS FRONT BUT IT
APPEARS THE 06/07Z RUC HAS THE BEST HANDLE ON ITS CURRENT AND
FORECAST POSITIONS OUT THROUGH 18Z. AS IS TYPICAL WITH A MORNING
COLD FRONTAL PASSAGE...MOS HIGHS SHOULD BE SEVERAL DEGREES TOO
COOL AS THEY RESOLVE A WIDE/BLURRED FRONTAL ZONE RATHER THAN THE
TIGHT TEMPERATURE GRADIENT THAT ACTUALLY EXISTS. MY FORECAST HIGHS
ARE 2-3 DEGREES ABOVE MOS (63-68...WARMEST NEAR GEORGETOWN)
ALTHOUGH THESE READINGS SHOULD OCCUR ONLY BRIEFLY AT THE TIME OF
FRONTAL PASSAGE WITH FALLING TEMPERATURES EXPECTED THROUGHOUT THE
AFTERNOON.
RADAR COMPOSITES REVEAL LARGE AREA OF VERY LIGHT SHOWERY RAIN ACROSS
THE CAROLINAS CURRENTLY. THIS APPEARS TO BE ASSOCIATED WITH WEAK
ISENTROPIC LIFT WITHIN A MID-LAYER CLOUD DECK 7000-12000 FT AGL.
MODELS SHOW ISENTROPIC LIFT HAVING ITS GREATEST MAGNITUDE (AND
THAT`S NOT SAYING MUCH) BETWEEN NOW AND NOON...WITH NEUTRAL TO
ISENTROPIC DOWNGLIDE CONDITIONS DEVELOPING DURING THE AFTERNOON. MY
QPF NUMBERS ARE BARELY A TENTH OF AN INCH OR LESS IN MOST SPOTS.
CLOUDS WILL PROBABLY NOT BREAK IN ANY SUBSTANTIAL SENSE DURING THE
DAY...AND THE LACK OF INSOLATION WILL NOT BE ABLE TO OFFSET
STRENGTHENING COLD ADVECTION DURING THE AFTERNOON.
FOR TONIGHT HIGH PRESSURE OVER THE CENTRAL PLAINS WILL SURGE
EASTWARD AS A SHORTWAVE EMBEDDED IN THE NORTHEASTERN U.S. TROUGH
SWINGS THROUGH VIRGINIA. THIS WILL LEAD TO THE REAL ARCTIC SURGE OF
THIS EVENT DEVELOPING AROUND OR JUST BEFORE MIDNIGHT. 850 MB
TEMPERATURES WILL FALL FROM AROUND +6C THIS EVENING TO -3C BY
DAYBREAK SUNDAY...AS WINDS AT THE TOP OF THE WELL-MIXED BOUNDARY
LAYER WINDS INCREASE TO 20-30 KNOTS. THE TEMPERATURE FORECAST
TONIGHT IS ACTUALLY QUITE TRICKY AS STRONG WINDS AND GOOD MIXING CAN
SOMETIMES CREATE A NIGHTTIME DEEP DRY-ADIABATIC PROFILE TYPICAL OF
DAYTIME CONDITIONS...WITH LOW TEMPERATURES ENDING UP MUCH WARMER
THAN ONE WOULD THINK POSSIBLE GIVEN THE AIRMASS. MY FORECAST LOWS
ARE A BIT ABOVE MOS GUIDANCE AND RANGE FROM NEAR FREEZING FROM
LUMBERTON TO DARLINGTON...TO 35-38 AT THE COAST.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 3 AM SATURDAY...COLD AND DRY ARCTIC HIGH BUILDS IN SUNDAY WITH
TEMPERATURES FALLING SHORT OF 50 DURING THE DAY. SURFACE RIDGE AXIS
SHIFTS CLOSE TO THE REGION SUN NIGHT...ENDING COLD ADVECTION BUT
PUTTING RADIATIONAL COOLING IN PLAY. DEEP DRY AIR...LIGHT
WINDS...AND UNSEASONABLY COLD AIR IN PLACE WILL RESULT IN LOWS IN
THE LOW TO MID 20S IN MANY LOCATIONS WITH ISOLATED UPPER TEENS
POSSIBLE INLAND.
WHILE SOME AIR MASS MODIFICATION IS EXPECTED ON MON VERY LOW
STARTING TEMPS COMBINED WITH NORTHEAST FLOW WILL AGAIN KEEP HIGHS
WELL BELOW CLIMO. INCREASING HIGH CLOUD MON AFTERNOON WILL LIMIT
INSOLATION...FURTHER HINDERING TEMP RECOVERY. CLOUDS START TO LOWER
MON NIGHT AS WEAK ISENTROPIC LIFT IS ENHANCED BY DEVELOPMENT OF WEAK
COASTAL TROUGH MON NIGHT. GIVEN THE DEPTH OF THE DRY AIR AND THE
PROPENSITY OF GUIDANCE TO UNDERESTIMATE THE DRY AIR AND THUS
INTRODUCE POP A LITTLE TOO EARLY DO NOT PLAN MAJOR CHANGES TO
INHERITED PRECIP CHANCES MON NIGHT. INCREASING CLOUD COVER WILL HELP
KEEPS MON NIGHT LOWS SIGNIFICANTLY WARMER THAN SUN NIGHT AND MORE
IMPORTANTLY ABOVE FREEZING.
AT THIS POINT IT DOES NOT APPEAR THE MONDAY MORNING RECORD LOWS WILL
BE IN PLAY.
RECORD LOWS FOR NOVEMBER 25 AND THE NORMALS:
--------------------------------------------
ILM - 20 - 1970 NORMAL - 43
FLO - 17 - 1950 NORMAL - 41
CRE - 17 - 1950 NORMAL - 44
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 3 AM SATURDAY...PERIOD BEGINS WITH A SOUTHERN STREAM SYSTEM
ALREADY AFFECTING THE REGION. ISENTROPIC LIFT WILL TAP INTO DEEP
MOISTURE SPREADING OVER THE AREA AHEAD OF THE GULF COAST SYSTEM ON
TUE. THIS WILL LEAD TO RAIN WITH INTENSITY GRADUALLY INCREASING
THROUGHOUT THE DAY. AT THIS POINT THE MEDIUM RANGE SOLUTIONS DIVERGE
SOMEWHAT. DISTANCE WISE THE TRACKS ARE NOT FAR APART...BUT AS IS
USUALLY THE CASE FOR THE COASTAL CAROLINAS A SMALL DIFFERENCE IN THE
TRACK COULD LEAD TO HUGE DIFFERENCES IN THE FORECAST. WHAT IS KNOWN
IS A POTENT STORM IS LIKELY TO IMPACT THE REGION WITH HEAVY RAIN AND
GUSTY WINDS LATE TUE NIGHT AND WED. THE NATURE OF THE
RAIN...STRATIFORM AS OPPOSED TO MORE CONVECTIVE AND HIGH/LOW
TEMPERATURES ARE WHAT REMAIN UNCERTAIN. AN INLAND TRACK WOULD LEAD
TO WARMER TEMPERATURES BUT ALSO OPEN UP THE POSSIBILITY OF SEVERE
WEATHER. THE INHERITED FORECAST LIES IN THE MIDDLE OF THE GUIDANCE
ENVELOPE AND REMAINS IN GOOD AGREEMENT WITH THE GFS ENSEMBLES.
THEREFORE WILL NOT MAKE MANY CHANGES AT THIS TIME.
SURFACE HIGH BUILDS IN BEHIND THE EXITING SYSTEM BUT THE MID LEVEL
PATTERN REMAINS MORE PROGRESSIVE WHICH KEEPS COLDEST AIR NORTH OF
THE AREA. COLD ADVECTION THU INTO FRI WILL HOLD TEMPERATURES BELOW
CLIMO BUT NOT SEVERAL CATEGORIES BELOW.
&&
.AVIATION /08Z SATURDAY THROUGH WEDNESDAY/...
AS OF 06Z...VFR WILL SOON DETERIORATE TO MVFR/POSSIBLE IFR AND
PERSIST THROUGH THIS AFTERNOON AS A COLD FRONT BRINGS UNSETTLED
WEATHER. TOWARDS THE END OF THE TAF PERIOD...ANTICIPATE CONDITIONS
TO IMPROVE TO VFR.
FOR THE EARLY MORNING HOURS...MID CLOUDS WILL LOWER TO MVFR AS
ILLUSTRATED BY LATEST MODELS...JUST AHEAD OF AN APPROACHING
ARCTIC COLD FRONT SITUATED BETWEEN KAVL AND KCLT. COULD NOT
COMPLETELY RULE OUT CIGS LOWERING EVEN MORE TO IFR...HOWEVER
CONFIDENCE REMAINS TOO LOW. FOG DEVELOPMENT IS POSSIBLE...ESPECIALLY
WITH ANY RAINFALL. RAIN CHANCES SHOULD PEAK AROUND THE TIME OF THE
FRONTAL PASSAGE...GENERALLY 10Z INLAND AND 13-14Z COAST. BEHIND THE
FRONT...EXPECT MVFR CEILINGS TO PERSIST INTO THIS EVENING...WITH
LINGERING -RA POSSIBLE THROUGH EARLY AFTERNOON. BY THIS EVENING...
CLOUDS SHOULD BREAK...WITH INCREASINGLY GUSTY NORTH WINDS.
EXTENDED OUTLOOK...VFR WITH BREEZY CONDITIONS EXPECTED ON SUNDAY.
VFR EXPECTED ON MONDAY...WITH LOW PRESSURE BRINGING RAIN
TUESDAY AND WEDNESDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 3 AM SATURDAY...BIG CHANGES ARE COMING OVER THE NEXT 12-24
HOURS AS AN ARCTIC COLD FRONT MOVES ACROSS THE AREA. THE FRONT
ITSELF WILL MOVE ACROSS THE COASTAL WATERS LATE THIS MORNING...
SHIFTING OUR SOUTHWEST WINDS AROUND TO THE NORTH BUT WITHOUT ANY
IMMEDIATE INCREASE IN SPEED. THAT WILL WAIT UNTIL THIS EVENING
WHEN HIGH PRESSURE OVER THE CENTRAL PLAINS SURGES EAST AND BEGINS
TO PUSH VERY CHILLY AIR OFFSHORE. NORTH WINDS SHOULD INCREASE TO
25-30 KNOTS AFTER MIDNIGHT. MODELS SHOW WINDS AT 1000-1500 FT
ABOVE GROUND LEVEL REACHING 35 KNOTS...AND FOR THIS REASON A GALE
WATCH HAS BEEN ISSUED FOR THE POTENTIAL THESE WINDS WILL MIX DOWN
TO THE OCEAN SURFACE IN GUSTS LATE TONIGHT. THE COLD AIR GALE
EVENT WE HAD EARLIER THIS MONTH FEATURED WINDS ABOUT 5 KNOTS
STRONGER AT 1000-1500 FT ALTITUDE THAN WHAT IS EXPECTED
TONIGHT...SO IT IS NOT GUARANTEED WE WILL SEE GALE-FORCE GUSTS
ACTUALLY MEASURED AT THE GROUND/OCEAN SURFACE.
SEAS CURRENTLY ARE 4 FT OUT AT THE FRYING PAN SHOALS BUOY AND 2 FT
AT THE BUOY SOUTH OF THE MOUTH OF THE CAPE FEAR RIVER. SEAS SHOULD
NOT CHANGE APPRECIABLY UNTIL LATE THIS EVENING...BUT WILL REALLY
START TO BUILD AFTER MIDNIGHT IN RESPONSE TO THE INCREASING WIND
SPEEDS. DOMINANT WAVE PERIODS CURRENTLY AROUND 8 SECONDS SHOULD
SHORTLY CONSIDERABLY ONCE THE WINDS START CRANKING AFTER MIDNIGHT.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 3 AM SATURDAY...STRONG NORTHERLY FLOW CONTINUES SUN WITH SOLID
SCA CONDITIONS FOR AT LEAST THE FIRST HALF OF THE DAY. COLD
ADVECTION AND PRESSURE GRADIENT START TO WEAKEN LATER IN THE DAY
WITH WINDS DROPPING UNDER 20 KT IN THE EVENING. WINDS VEER TO
NORTHEAST SUN NIGHT AND MON AS CENTER OF SURFACE HIGH MOVES OVER
EASTERN NORTH CAROLINA. WEAK COASTAL TROUGH STARTS TO DEVELOP LATER
MON AND MON NIGHT AS SURFACE HIGH BECOMES ELONGATED TO THE
NORTHEAST. NEARSHORE WINDS WILL REMAIN NORTHEAST BUT CLOSER TO 20 NM
VARIABLE OR EVEN SOUTHEAST WINDS MAY DEVELOP BEFORE THE END OF THE
PERIOD. GRADIENT REMAINS WEAK IN THE VICINITY OF THE TROUGH WHICH
WILL KEEP WIND SPEEDS CLOSER TO 10 KT MON NIGHT. SEAS 4 TO 7 FT TO
START THE PERIOD FALL TO 3 TO 5 FT SUN NIGHT AND CONTINUE TO DROP AS
WINDS VEER AND WEAKEN. BY THE END OF THE PERIOD SEAS WILL BE 2 TO 3
FT.
LONG TERM /TUESDAY THROUGH WEDNESDAY/...
AS OF 3 AM SATURDAY...LARGE AMOUNT OF UNCERTAINTY FOR THE PERIOD AS
FAR AS WIND DIRECTION IS CONCERNED. THINK SCA EVENT IS IN THE WORKS
TUE NIGHT OR WED AS STRENGTHENING LOW PRESSURE SYSTEM EMERGING FROM
THE NORTHERN GULF OF MEXICO TRAVELS UP THE EAST COAST. THE TRACK OF
THE LOW REMAINS THE STICKING POINT AND WILL DETERMINE WIND
DIRECTION. CONFIDENT STRONG EAST TO SOUTHEAST FLOW WILL DEVELOP ON
TUE BUT FROM THERE CONFIDENCE DROPS. AT THIS POINT THE FAVORED
SOLUTION IS A TRACK JUST INLAND OF THE COAST WHICH LEADS TO STRONG
SOUTHERLY FLOW BECOMING SOUTHWEST LATE TUE NIGHT. SOUTHWEST WINDS
VEER TO NORTHWEST ON WED AS THE COLD FRONT PUSHES OFF THE COAST AND
HIGH PRESSURE STARTS TO BUILD IN. THE ELEVATED WIND SPEEDS COMBINED
WITH THE VARYING DIRECTIONS WILL RESULT IN A VERY CHAOTIC SEA STATE
FOR MUCH OF THE PERIOD. SEAS BUILD TUE INTO TUE NIGHT...REACHING 5
TO 8 FT AT THEIR ZENITH...THEN SLOWLY SUBSIDING DURING WED AS
OFFSHORE FLOW DEVELOPS AND INCREASES.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...GALE WATCH FROM LATE TONIGHT THROUGH SUNDAY MORNING FOR AMZ250-
252-254-256.
&&
$$
NEAR TERM...TRA
SHORT TERM...III
LONG TERM...III
AVIATION...SGL/TRA
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1232 AM EST SAT NOV 23 2013
.SYNOPSIS...
A STRONG ARCTIC COLD FRONT WILL CROSS THE AREA SATURDAY MORNING
FOLLOWED BY THE COLDEST TEMPERATURES OF THE SEASON. A SIGNIFICANT
RAIN EVENT APPEARS LIKELY FOR THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
AS OF 1230 AM SATURDAY...ASIDE FROM RAISING FORECAST LOWS BY A
COUPLE DEGREES AND INCREASING FORECAST CLOUD COVERAGE...NO
SIGNIFICANT CHANGES ARE NEEDED. PREVIOUS DISCUSSION FROM 1030 PM
FOLLOWS...
LATEST SFC ANALYSIS PLACES THE ARCTIC FRONT IN THE NC MTNS. MOISTURE
ESPECIALLY IN THE LOW AND MID LEVELS WILL CONTINUE TO OVERSPREAD THE
FA OVERNIGHT. MAIN BELT OF MOISTURE WILL RESIDE ALONG THE IMMEDIATE
ARCTIC FRONT...AS WELL AS AFTER ITS PASSAGE. LATEST HRRR ILLUSTRATES
-SHRA ACTIVITY TO REACH AND/OR BREAKOUT ACROSS THE NW PORTIONS OF
THE FA AFTER MIDNIGHT...AND SLOWLY PUSH TO AND OFF THE COAST DURING
THE AM DAYLIGHT HOURS. ONCE THE ARCTIC FRONT CLEARS THE
MOUNTAINS...IT WILL PICK UP SPEED AND MOMENTUM AS IT TRACKS TO THE
EASTERN CAROLINAS BY DAYBREAK SATURDAY. HAVE BASICALLY KEPT CURRENT
POPS PEAKING IN THE GOOD CHANCE TO LIKELY CATEGORIES THROUGH
DAYBREAK SAT. STILL LOOKING AT RW- FOR PCPN TYPE...WITH NO THUNDER.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
AS OF 3 PM FRIDAY...A QUICK CHANGE IN THE TEMPERATURES IS ON TAP
STARTING SATURDAY MORNING AS A COLD FRONT WILL PUSH OFF THE COAST
AND BRING IN THE COLDEST AIR OF THE SEASON.
THE MODELS ARE ALL SHOWING PRECIPITATION ALONG THE FRONT AND JUST
BEHIND THE FRONT AS IT SWEEPS OFF THE COAST. THE LATEST 09 UTC
SREF IS SHOWING A 90% CHANCE OF MEASURABLE PRECIPITATION BUT THE
PROBABILITIES FOR GREATER THAN 0.10 INCHES IS AROUND 50%. SO THIS
IMPLIES PROBABILITIES WILL BE HIGH BUT QPF WILL BE LESS THAN
EARLIER ADVERTISE.
THE OTHER STORY WILL BE THE COLD AIR THAT WILL BE ADVECTING INTO
THE REGION. LOWS WILL DROP INTO THE MIDDLE 30S SATURDAY NIGHT AND
THE MIDDLE 20S ON SUNDAY NIGHT...AND THESE COLD TEMPERATURES WILL
THREATEN THE RECORD LOWS FOR THE 25TH ALONG THE COAST.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 3 PM FRIDAY...COLD AND QUIET TO START THE PERIOD...BUT A
SIGNIFICANT STORM SYSTEM IS LOOKING MORE LIKELY TO IMPACT THE
REGION FOR THE MID-WEEK PERIOD.
ARCTIC HIGH PRESSURE WILL BE ENTRENCHED OVER THE AREA ON
MONDAY...AND WITH A VERY COLD MORNING FROM WHICH TO
RECOVER...SUNSHINE WILL ONLY HELP TEMPS RISE INTO THE 40S TO AROUND
50 ON MONDAY...OR ABOUT 15 DEGREES BELOW NORMAL. LOWS MONDAY NIGHT
WILL DROP TO BELOW CLIMO AS WELL...BUT DEVELOPING SOUTHERLY FLOW
WILL KEEP TEMPS MUCH WARMER THAN WHAT WILL BE EXPERIENCED AT THE
START OF THE PERIOD.
BIG CHANGES OCCUR THEREAFTER AS THE 5H PATTERN BECOMES HIGHLY
AMPLIFIED. CUTOFF SOUTHERN STREAM LOW ACROSS THE 4-CORNERS EJECTS
EASTWARD TOWARDS THE SOUTHEAST...WHILE A NORTHERN STREAM VORT MAX
DROPS ACROSS THE GREAT LAKES. IN A FLOW THAT IS NOT TOO FAST...THIS
IS A TYPICAL SETUP FOR A POTENTIAL COASTAL STORM AS THESE FEATURES
INTERACT ALONG THE COAST. THIS CASE APPEARS NO DIFFERENT...ALTHOUGH
TIMING AND INTENSITY DIFFERENCES STILL EXIST. THE ECM/CMC KEEP THE
SOUTHERN STREAM LOW MORE CLOSED AND AMPLIFIED...WHICH HELPS DEVELOP
A LOW IN THE GULF OF MEXICO WHICH WILL THEN RIDE UP THE EAST COAST.
THE GFS IS MORE PROGRESSIVE AND KEEPS THE LOW WELL OFFSHORE...BUT IS
NOTICEABLY EAST AND FASTER THAN MANY OF ITS ENSEMBLES. WILL FAVOR
FOR NOW THE ECM/CMC...BUT NOT FOCUS ON SPECIFICS SINCE THERE IS
STILL TEMPORAL AND SPATIAL UNCERTAINTY.
REGARDLESS...A -3SD 5H LOW IN THE GULF OF MEXICO IS A CLEAR SIGNAL
FOR STRONG CYCLOGENESIS...AND IT IS LIKELY THAT A LOW PRESSURE WILL
IMPACT THE LOCAL AREA BEGINNING TUESDAY NIGHT AND LASTING THROUGH
WEDNESDAY. AMPLE MOISTURE WILL BE PRESENT...COMMON OF COURSE WITH A
LOW FROM THE GULF OF MEXICO...AND MDT/HVY RAIN WILL OVERSPREAD THE
AREA...WITH CONSIDERABLE QPF POSSIBLE. ADDITIONALLY...IF THE INLAND
TRACK VERIFIES...THE COASTAL SECTIONS OF THE AREA WILL BE
WARM-SECTORED...HENCE CREATING A NON-ZERO SEVERE THREAT...WITH
STRONG LOW-LEVEL SHEAR EAST OF THE COASTAL/WARM FRONT. THE ONE THING
THAT DOES...NOT...APPEAR TO BE A PROBLEM WITH THIS EVENT WILL BE
WINTRY PRECIP. BY THE TIME COLD ENOUGH AIR WORKS INTO THE
CWA...MOISTURE WILL BE GONE. NEVERTHELESS...A SIGNIFICANT WEATHER
EVENT THE DAY BEFORE THANKSGIVING COULD LEAD TO WIDESPREAD TRAVEL
HEADACHES.
TEMPS TUE/WED WILL BE TRICKY AS A WEDGE SETUP WILL KEEP INLAND TEMPS
MUCH COOLER THAN THE COAST...AND A 10-15 DEGREE TEMP GRADIENT ACROSS
THE CWA IS POSSIBLE. THURS/FRI WILL BE DRY BEHIND THE DEPARTING
SYSTEM...BUT WELL BELOW NORMAL AS CAA DEVELOPS ON NORTH WINDS.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
AS OF 06Z...VFR WILL SOON DETERIORATE TO MVFR/POSSIBLE IFR AND
PERSIST THROUGH THIS AFTERNOON AS A COLD FRONT BRINGS UNSETTLED
WEATHER. TOWARDS THE END OF THE TAF PERIOD...ANTICIPATE CONDITIONS
TO IMPROVE TO VFR.
FOR THE EARLY MORNING HOURS...MID CLOUDS WILL LOWER TO MVFR AS
ILLUSTRATED BY LATEST MODELS...JUST AHEAD OF AN APPROACHING
ARCTIC COLD FRONT SITUATED BETWEEN KAVL AND KCLT. COULD NOT
COMPLETELY RULE OUT CIGS LOWERING EVEN MORE TO IFR...HOWEVER
CONFIDENCE REMAINS TOO LOW. FOG DEVELOPMENT IS POSSIBLE...ESPECIALLY
WITH ANY RAINFALL. RAIN CHANCES SHOULD PEAK AROUND THE TIME OF THE
FRONTAL PASSAGE...GENERALLY 10Z INLAND AND 13-14Z COAST. BEHIND THE
FRONT...EXPECT MVFR CEILINGS TO PERSIST INTO THIS EVENING...WITH
LINGERING -RA POSSIBLE THROUGH EARLY AFTERNOON. BY THIS EVENING...
CLOUDS SHOULD BREAK...WITH INCREASINGLY GUSTY NORTH WINDS.
EXTENDED OUTLOOK...VFR WITH BREEZY CONDITIONS EXPECTED ON SUNDAY.
VFR EXPECTED ON MONDAY...WITH LOW PRESSURE BRINGING RAIN
TUESDAY AND WEDNESDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1230 AM SATURDAY...NO SIGNIFICANT CHANGES ARE NEEDED. PREVIOUS
DISCUSSION FROM 1030 PM FOLLOWS...
A RELAXED SFC PRESSURE GRADIENT TO PREVAIL LEADING UP TO THE PASSAGE
OF THE ARCTIC COLD FRONT DURING THE AM HRS OF SATURDAY...AFTER
DAYBREAK. THE SFC PRESSURE PATTERN WILL BE CONDUCIVE FOR THE CURRENT
WESTERLY WIND DIRECTION THAT WILL VEER TO THE NW BY DAYBREAK SAT IN
RESPONSE TO THE ARCTIC COLD FRONT CLIMBING AT THE DOORSTEPS OF THE
FORECAST AREA. SIGNIFICANT SEAS WILL HOLD IN THE 2 TO 4 FOOT
RANGE...WITH A 2 TO 3 FOOT EASTERLY SWELL AT 8 TO 10 SECOND PERIODS
DOMINATING THE OVERALL WAVE SPECTRUM ACROSS THESE WATERS.
SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 3 PM FRIDAY...THE MARINE WATERS WILL BEING GOING DOWN HILL
QUICKLY AS A STRONG ARCTIC COLD FRONT CROSSES THE WATER BEGINNING
SATURDAY MORNING. THIS WILL BRING STRONG COLD AIR ADVECTION OVER
THE WATERS AND WIND SPEEDS JUST BELOW GALE CONDITIONS. SMALL CRAFT
CONDITION ARE GIVE BEGINNING LATE SATURDAY AND THE WATERS MAYBE
APPROACHING GALE CONDITION BY SUNRISE SUNDAY FOR A FEW HOURS.
MARINERS ARE ADVISE TO MONITOR THE FORECAST FOR A POSSIBLE GALE
WARNING IF THEY ARE NEEDED. SEAS WILL RISE TO 6 TO 8 FEET BY SUNDAY
MORNING.
LONG TERM /MONDAY THROUGH WEDNESDAY/...
AS OF 3 PM FRIDAY...QUIET MARINE CONDITIONS TO START THE PERIOD
WILL RAPIDLY DETERIORATE THROUGH MID-WEEK AS A COASTAL STORM WILL
POSSIBLY IMPACT THE AREA TUE/WED. HIGH PRESSURE NEAR THE AREA WILL
DRIFT E/NE THROUGH MONDAY...KEEPING WINDS LESS THAN 10 KTS AND
SHIFTING TO THE EAST THROUGH THE DAY. WINDS THEN INCREASE STEADILY
AS A COASTAL LOW IS EXPECTED TO DEVELOP AND MOVE UP THE COAST. THE
EXACT PLACEMENT AND TIMING OF THIS SYSTEM IS STILL IN QUESTION DUE
TO MODEL UNCERTAINTY...BUT EXPECT WINDS TO INCREASE FROM THE SE ON
TUESDAY...BEFORE SHIFTING TO THE SW...AND EVENTUALLY NW ON WEDNESDAY
AS THE LOW MOVES TO THE NE. WINDS SPEEDS WILL BE AROUND 15-20
KTS...POSSIBLY STRONGER...REGARDLESS OF DIRECTION DURING THIS TIME.
THIS WILL CREATE HAZARDOUS SEAS...WITH WAVE HEIGHTS RISING TO 4-7 FT
FROM SEVERAL DIFFERENT DIRECTIONS. A SMALL CRAFT ADVISORY IS
POSSIBLE TUESDAY AND WEDNESDAY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...DRH
NEAR TERM...DCH/TRA
SHORT TERM...DRH
LONG TERM...JDW
AVIATION...SGL/TRA
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1106 PM EST FRI NOV 22 2013
.SYNOPSIS...
A STRONG ARCTIC COLD FRONT WILL CROSS THE AREA SATURDAY MORNING
FOLLOWED BY THE COLDEST TEMPERATURES OF THE SEASON. A SIGNIFICANT
RAIN EVENT APPEARS LIKELY FOR THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
AS OF 1015 PM FRIDAY...LATEST SFC ANALYSIS PLACES THE ARCTIC FRONT
ROUGHLY ALONG A LINE BETWEEN MWK-TNB-FQD-1A5-RHP. WHICH STILL
KEEPS IT TEMPORARILY HUNG-UP ACROSS THE APPALACHIAN MOUNTAINS.
MOISTURE ESPECIALLY IN THE LOW AND MID LEVELS WILL CONTINUE TO
OVERSPREAD THE FA OVERNIGHT. MAIN BELT OF MOISTURE WILL RESIDE
ALONG THE IMMEDIATE ARCTIC FRONT...AS WELL AS AFTER ITS PASSAGE.
LATEST HRRR ILLUSTRATES -SHRA ACTIVITY TO REACH AND/OR BREAKOUT
ACROSS THE NW PORTIONS OF THE FA AFTER MIDNIGHT...AND SLOWLY PUSH
TO AND OFF THE COAST DURING THE AM DAYLIGHT HOURS. ONCE THE ARCTIC
FRONT CLEARS THE MOUNTAINS...IT WILL PICK UP SPEED AND MOMENTUM AS
IT TRACKS TO THE EASTERN CAROLINAS BY DAYBREAK SATURDAY. HAVE
BASICALLY KEPT CURRENT POPS PEAKING IN THE GOOD CHANCE TO LIKELY
CATEGORIES THROUGH DAYBREAK SAT. STILL LOOKING AT RW- FOR PCPN
TYPE...WITH NO THUNDER.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
AS OF 3 PM FRIDAY...A QUICK CHANGE IN THE TEMPERATURES IS ON TAP
STARTING SATURDAY MORNING AS A COLD FRONT WILL PUSH OFF THE COAST
AND BRING IN THE COLDEST AIR OF THE SEASON.
THE MODELS ARE ALL SHOWING PRECIPITATION ALONG THE FRONT AND JUST
BEHIND THE FRONT AS IT SWEEPS OFF THE COAST. THE LATEST 09 UTC
SREF IS SHOWING A 90% CHANCE OF MEASURABLE PRECIPITATION BUT THE
PROBABILITIES FOR GREATER THAN 0.10 INCHES IS AROUND 50%. SO THIS
IMPLIES PROBABILITIES WILL BE HIGH BUT QPF WILL BE LESS THAN
EARLIER ADVERTISE.
THE OTHER STORY WILL BE THE COLD AIR THAT WILL BE ADVECTING INTO
THE REGION. LOWS WILL DROP INTO THE MIDDLE 30S SATURDAY NIGHT AND
THE MIDDLE 20S ON SUNDAY NIGHT...AND THESE COLD TEMPERATURES WILL
THREATEN THE RECORD LOWS FOR THE 24TH ALONG THE COAST.
RECORD LOWS - DECEMBER 24TH
ILM - 23 IN 1970.
FLO - 19 IN 1970.
CRE - 28 IN 2008
(NOTE RECORDS FOR NORTH MYRTLE BEACH/MYRTLE BEACH ARE FOR
1948-1956 AND 1988-PRESENT AND 1970 TEMPERATURES WAS NOT
RECORDED).
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 3 PM FRIDAY...COLD AND QUIET TO START THE PERIOD...BUT A
SIGNIFICANT STORM SYSTEM IS LOOKING MORE LIKELY TO IMPACT THE
REGION FOR THE MID-WEEK PERIOD.
ARCTIC HIGH PRESSURE WILL BE ENTRENCHED OVER THE AREA ON
MONDAY...AND WITH A VERY COLD MORNING FROM WHICH TO
RECOVER...SUNSHINE WILL ONLY HELP TEMPS RISE INTO THE 40S TO AROUND
50 ON MONDAY...OR ABOUT 15 DEGREES BELOW NORMAL. LOWS MONDAY NIGHT
WILL DROP TO BELOW CLIMO AS WELL...BUT DEVELOPING SOUTHERLY FLOW
WILL KEEP TEMPS MUCH WARMER THAN WHAT WILL BE EXPERIENCED AT THE
START OF THE PERIOD.
BIG CHANGES OCCUR THEREAFTER AS THE 5H PATTERN BECOMES HIGHLY
AMPLIFIED. CUTOFF SOUTHERN STREAM LOW ACROSS THE 4-CORNERS EJECTS
EASTWARD TOWARDS THE SOUTHEAST...WHILE A NORTHERN STREAM VORT MAX
DROPS ACROSS THE GREAT LAKES. IN A FLOW THAT IS NOT TOO FAST...THIS
IS A TYPICAL SETUP FOR A POTENTIAL COASTAL STORM AS THESE FEATURES
INTERACT ALONG THE COAST. THIS CASE APPEARS NO DIFFERENT...ALTHOUGH
TIMING AND INTENSITY DIFFERENCES STILL EXIST. THE ECM/CMC KEEP THE
SOUTHERN STREAM LOW MORE CLOSED AND AMPLIFIED...WHICH HELPS DEVELOP
A LOW IN THE GULF OF MEXICO WHICH WILL THEN RIDE UP THE EAST COAST.
THE GFS IS MORE PROGRESSIVE AND KEEPS THE LOW WELL OFFSHORE...BUT IS
NOTICEABLY EAST AND FASTER THAN MANY OF ITS ENSEMBLES. WILL FAVOR
FOR NOW THE ECM/CMC...BUT NOT FOCUS ON SPECIFICS SINCE THERE IS
STILL TEMPORAL AND SPATIAL UNCERTAINTY.
REGARDLESS...A -3SD 5H LOW IN THE GULF OF MEXICO IS A CLEAR SIGNAL
FOR STRONG CYCLOGENESIS...AND IT IS LIKELY THAT A LOW PRESSURE WILL
IMPACT THE LOCAL AREA BEGINNING TUESDAY NIGHT AND LASTING THROUGH
WEDNESDAY. AMPLE MOISTURE WILL BE PRESENT...COMMON OF COURSE WITH A
LOW FROM THE GULF OF MEXICO...AND MDT/HVY RAIN WILL OVERSPREAD THE
AREA...WITH CONSIDERABLE QPF POSSIBLE. ADDITIONALLY...IF THE INLAND
TRACK VERIFIES...THE COASTAL SECTIONS OF THE AREA WILL BE
WARM-SECTORED...HENCE CREATING A NON-ZERO SEVERE THREAT...WITH
STRONG LOW-LEVEL SHEAR EAST OF THE COASTAL/WARM FRONT. THE ONE THING
THAT DOES...NOT...APPEAR TO BE A PROBLEM WITH THIS EVENT WILL BE
WINTRY PRECIP. BY THE TIME COLD ENOUGH AIR WORKS INTO THE
CWA...MOISTURE WILL BE GONE. NEVERTHELESS...A SIGNIFICANT WEATHER
EVENT THE DAY BEFORE THANKSGIVING COULD LEAD TO WIDESPREAD TRAVEL
HEADACHES.
TEMPS TUE/WED WILL BE TRICKY AS A WEDGE SETUP WILL KEEP INLAND TEMPS
MUCH COOLER THAN THE COAST...AND A 10-15 DEGREE TEMP GRADIENT ACROSS
THE CWA IS POSSIBLE. THURS/FRI WILL BE DRY BEHIND THE DEPARTING
SYSTEM...BUT WELL BELOW NORMAL AS CAA DEVELOPS ON NORTH WINDS.
&&
.AVIATION /04Z SATURDAY THROUGH WEDNESDAY/...
AS OF 00Z...VFR EXPECTED THIS EVENING AS CONDITIONS BEGIN TO
DETERIORATE OVERNIGHT AND PERSIST THROUGH THE VALID TAF PERIOD AS
A COLD FRONTAL PASSAGE BRINGS UNSETTLED WEATHER...ALONG WITH
LOWERED CIGS AND PATCHY FOG.
LIGHT SHOWERS THAT MOVED ACROSS THE AREA EARLIER HAVE SINCE
DISSIPATED THOUGH LATEST OBS SHOW THAT RESIDUAL FOG AT KCRE
CONTINUES...CREATING MVFR ATTM. INTO THE OVERNIGHT HOURS...EXPECT
SOUTH-SOUTHWEST WINDS AOB 5 KTS. CLOUDS ACROSS THE AREA WILL
INCREASE AND CIGS WILL LOWER TO MVFR AS ILLUSTRATED BY LATEST
TIME-HEIGHT ANALYSIS AND FCST SOUNDINGS...JUST AHEAD OF AN
APPROACHING ARCTIC COLD FRONT. COULD NOT COMPLETELY RULE OUT CIGS
LOWERING EVEN MORE TO IFR...HOWEVER CONFIDENCE REMAINS LOW. WILL
ALSO MENTION THAT FOG IS POSSIBLE AS WELL...ESPECIALLY ASSOCIATED
WITH RAIN ACTIVITY...BUT EXPECT LOWERED RESTRICTIONS TO BE MORE
CORRELATED TO LOWERED CIGS. EXPECT RAIN CHANCES TO INCREASE AS WELL
JUST AHEAD AND ALONG THE FRONTAL BOUNDARY...WHICH WILL PUSH THROUGH
LATE OVERNIGHT INTO THE MORNING HOURS FROM WEST TO EAST. BEHIND THE
FRONTAL PASSAGE...EXPECT MVFR CONDITIONS TO PERSIST DUE TO LOW CIGS
THROUGH SATURDAY EARLY EVENING...WITH LINGERING ISOLATED AREAS OF
-RA POSSIBLE. WINDS WILL BECOME NORTHERLY AOB 10 KTS...WITH SLIGHTLY
HIGHER WINDS POSSIBLE ALONG THE COAST.
EXTENDED OUTLOOK...EXPECT BREEZY VFR CONDITIONS FOLLOWING FROPA ON
SUNDAY. VFR ON MONDAY. SHOWERS LIKELY ON TUESDAY AND WEDNESDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1045 PM FRIDAY...A RELAXED SFC PRESSURE GRADIENT TO PREVAIL
LEADING UP TO THE PASSAGE OF THE ARCTIC COLD FRONT DURING THE AM
HRS OF SATURDAY...AFTER DAYBREAK. THE SFC PRESSURE PATTERN WILL BE
CONDUCIVE FOR THE CURRENT WESTERLY WIND DIRECTION THAT WILL VEER
TO THE NW BY DAYBREAK SAT IN RESPONSE TO THE ARCTIC COLD FRONT
CLIMBING AT THE DOORSTEPS OF THE FORECAST AREA. SIGNIFICANT SEAS
WILL HOLD IN THE 2 TO 4 FOOT RANGE...WITH A 2 TO 3 FOOT EASTERLY
SWELL AT 8 TO 10 SECOND PERIODS DOMINATING THE OVERALL WAVE
SPECTRUM ACROSS THESE WATERS.
SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 3 PM FRIDAY...THE MARINE WATERS WILL BEING GOING DOWN HILL
QUICKLY AS A STRONG ARCTIC COLD FRONT CROSSES THE WATER BEGINNING
SATURDAY MORNING. THIS WILL BRING STRONG COLD AIR ADVECTION OVER
THE WATERS AND WIND SPEEDS JUST BELOW GALE CONDITIONS. SMALL CRAFT
CONDITION ARE GIVE BEGINNING LATE SATURDAY AND THE WATERS MAYBE
APPROACHING GALE CONDITION BY SUNRISE SUNDAY FOR A FEW HOURS.
MARINERS ARE ADVISE TO MONITOR THE FORECAST FOR A POSSIBLE GALE
WARNING IF THEY ARE NEEDED. SEAS WILL RISE TO 6 TO 8 FEET BY SUNDAY
MORNING.
LONG TERM /MONDAY THROUGH WEDNESDAY/...
AS OF 3 PM FRIDAY...QUIET MARINE CONDITIONS TO START THE PERIOD
WILL RAPIDLY DETERIORATE THROUGH MID-WEEK AS A COASTAL STORM WILL
POSSIBLY IMPACT THE AREA TUE/WED. HIGH PRESSURE NEAR THE AREA WILL
DRIFT E/NE THROUGH MONDAY...KEEPING WINDS LESS THAN 10 KTS AND
SHIFTING TO THE EAST THROUGH THE DAY. WINDS THEN INCREASE STEADILY
AS A COASTAL LOW IS EXPECTED TO DEVELOP AND MOVE UP THE COAST. THE
EXACT PLACEMENT AND TIMING OF THIS SYSTEM IS STILL IN QUESTION DUE
TO MODEL UNCERTAINTY...BUT EXPECT WINDS TO INCREASE FROM THE SE ON
TUESDAY...BEFORE SHIFTING TO THE SW...AND EVENTUALLY NW ON WEDNESDAY
AS THE LOW MOVES TO THE NE. WINDS SPEEDS WILL BE AROUND 15-20
KTS...POSSIBLY STRONGER...REGARDLESS OF DIRECTION DURING THIS TIME.
THIS WILL CREATE HAZARDOUS SEAS...WITH WAVE HEIGHTS RISING TO 4-7 FT
FROM SEVERAL DIFFERENT DIRECTIONS. A SMALL CRAFT ADVISORY IS
POSSIBLE TUESDAY AND WEDNESDAY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...DRH
NEAR TERM...DCH
SHORT TERM...DRH
LONG TERM...JDW
AVIATION...SGL
AREA FORECAST DISCUSSION
NWS TULSA OK
924 PM CST SUN NOV 24 2013
...UPDATE...
.DISCUSSION...
INITIAL WAVE OF MIXED WINTRY PRECIP HAS EXITED
THE FORECAST AREA...WITH SEVERAL EARLIER REPORTS
OF SLICK SPOTS/SLIDE-OFFS ACROSS SE OK/WCNTRL AR.
NEXT ROUND OF WINTER PRECIP IS CURRENTLY ORGANIZING
ACROSS NRN TX...AND PRECIP WILL BEGIN TO EXPAND
TO THE ENE OVERNIGHT AS ISENTROPIC LIFT (MOST NOTABLY
ALONG 300K SFC ATOP DRY LAYER) INCREASES. SFC TEMPS
ACROSS THE ADVISORY AREA ARE CURRENTLY RUNNING AROUND
28-32F...ALTHOUGH T/TD SPREADS SUGGEST SOME WET-BULBING
IS LIKELY ONCE PRECIP INCREASES IN COVERAGE/INTENSITY.
CURRENT FORECAST IS IN REASONABLE ENOUGH SHAPE...BUT
HAVE BUMPED UP POPS ACROSS THE SE AFTER 09Z...MORE
IN-LINE WITH LATEST HRRR OUTPUT. PRECIP MAY START AS
RAIN/SLEET ACROSS FAR SE OK...WITH A CHANGEOVER TO
SLEET...FREEZING RAIN AND POSSIBLY SOME SNOW LATER
TONIGHT. TRAVEL IMPACTS WILL MAINLY BE ON ELEVATED
ROAD SURFACES...BUT WILL NEED TO CLOSELY MONITOR SE OK.
UPDATED PRODUCTS OUT SHORTLY.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 27 36 26 43 / 40 30 10 0
FSM 29 35 30 44 / 60 60 20 10
MLC 28 35 27 42 / 60 60 20 10
BVO 26 37 24 42 / 20 30 10 0
FYV 26 34 25 40 / 40 50 20 10
BYV 26 34 25 39 / 10 30 20 10
MKO 27 35 26 42 / 50 50 10 10
MIO 27 36 24 41 / 10 20 10 0
F10 26 35 26 41 / 60 40 10 10
HHW 29 35 31 43 / 80 90 40 20
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...WINTER WEATHER ADVISORY UNTIL NOON MONDAY FOR OKZ049-OKZ053-
OKZ071-OKZ072-OKZ073-OKZ074-OKZ075-OKZ076.
AR...WINTER WEATHER ADVISORY UNTIL NOON MONDAY FOR ARZ019-ARZ020-
ARZ029.
&&
$$
SHORT TERM...18
AREA FORECAST DISCUSSION
NWS PORTLAND OR
245 AM PST FRI NOV 22 2013
.SYNOPSIS...HIGH PRESSURE OVER THE PACIFIC NORTHWEST WILL MAINTAIN
DRY AND COOL CONDITIONS INTO NEXT WEEK. A STORM SYSTEM LOOKS
INCREASINGLY LIKELY TO SHIFT SOUTH OF THE REGION...BUT THERE IS
STILL A SMALL CHANCE A FEW SHOWERS COULD SPREAD INTO OUR COASTAL
AND SOUTHERN ZONES DURING THE MIDDLE PART OF NEXT WEEK.
&&
.SHORT TERM...PRESSURE GRADIENTS CONTINUE TO INCREASE ACROSS THE
CASCADES WITH THE KTTD-KDLS GRADIENT APPROACHING 10MB. AS SUCH...
WINDS SHOULD CONTINUE TO STRENGTHEN THIS MORNING WITH GUSTS
APPROACHING 45 MPH AROUND TROUTDALE. 40 TO 60 MPH GUSTS WILL BE
COMMON ACROSS THE WESTERN COLUMBIA RIVER GORGE WITH GUSTS LIKELY
EXCEEDING 80 MPH AT CROWN POINT. AT THIS POINT...ALL MODELS
INCLUDING THE RAP ARE TRYING TO RELAX THE GRADIENT THIS
MORNING...BUT CLIMATOLOGY WOULD SUGGEST OTHERWISE. SO FAR POWER
OUTAGES HAVE BEEN RATHER MINIMAL...BUT IF THE CROSS CASCADE GRADIENT
STARTS TO TRACK MUCH LOWER THAN -10MB THEN WE MAY NEED TO ISSUE A
WIND ADVISORY FOR THE EASTERN SUBURBS OF PORTLAND.
ASIDE FROM A FEW HIGH CLOUDS OCCASIONALLY CREEPING ACROSS THE
NORTHERN HALF OF THE CWA...SKIES ARE CLEAR. WHEN COMBINED WITH
DEWPOINTS IN THE TEENS AND TWENTIES...TEMPERATURES HAVE ONCE AGAIN
FALLEN WELL BELOW FREEZING THIS MORNING AT MANY LOCATIONS.
HOWEVER...IT SHOULD BE NOTED THAT TEMPERATURES HAVE STAYED UP A BIT
HIGHER THAN EXPECTED AROUND MCMINNVILLE...AURORA...DALLAS...AND
SALEM WHERE NORTHERLY WINDS REMAIN 5 TO 10 KT. PRESUMABLY THIS IS
DUE TO THE SUBSIDENCE INVERSION LOWERING TO NEAR 1500 FEET...AND
THUS CAUSING THE GORGE WINDS TO BE BLOCKED BY THE COAST RANGE.
RATHER THAN SPREADING OUT EVENLY NORTH AND SOUTH...THE SYNOPTIC
SCALE NORTH TO SOUTH PRESSURE GRADIENT IS LIKELY AIDING IN MOST OF
THIS MASS SPREADING SOUTHWARD INTO THE CENTRAL AND SOUTHERN
WILLAMETTE VALLEY. PRESUMABLY ENOUGH RADIATIONAL COOLING WILL ALLOW
THE SURFACE TO DECOUPLE AT MANY OF THE AFOREMENTIONED LOCATIONS AT
SOME POINT TONIGHT...BUT GIVEN GORGE WINDS WILL LIKELY STRENGTHEN A
BIT OVER THE NEXT FEW HOURS...WE MAY BE IN FOR QUITE THE MIN
TEMPERATURE FORECAST BUST AT THESE LOCATIONS THIS MORNING.
OTHERWISE...THERE WILL NOT BE MUCH CHANGE OVER THE NEXT SEVERAL DAYS
AS HIGH PRESSURE CONTINUES. THE EAST TO WEST PRESSURE GRADIENT
SHOULD WEAKEN SLOWLY INTO THE MIDDLE PART OF NEXT WEEK...WHICH MEANS
THE STRONGER WINDS SHOULD SUBSIDE TO MORE NUISANCE LEVELS.
A SOUTHERLY WIND SHIFT SHOULD ALSO CAUSE MARINE CLOUDS TO PUSH UP
THE COAST SUNDAY INTO MONDAY...AND THUS LOW TEMPERATURES SHOULD
MODERATE ALONG THE COAST. FURTHER INLAND...THE LOWER ATMOSPHERE
SHOULD MOISTEN OVER THE NEXT COUPLE OF DAYS...INCREASING VALLEY FOG
AND LOW CLOUD DEVELOPMENT. HOWEVER...MOS NUMBERS DO NOT REALLY
SUGGEST THIS OUTCOME. AS A RESULT...WENT A LITTLE MORE MIDDLE OF THE
ROAD...BUMPING UP OUR MAX TEMPERATURES A BIT...WHILE TRYING TO KEEP
THEM BELOW MOS NUMBERS. /NEUMAN
.LONG TERM...MINIMAL CHANGES IN THE EXTENDED...PREVIOUS DISCUSSION
FOLLOWS...DRY WEATHER WILL CONTINUE NEXT WED UNDER HIGH PRES.
SOME BETTER AGREEMENT IN THE OPERATIONAL 12Z GFS AND ECMWF THAN
YESTERDAY. BOTH DEPICT A CLOSED LOW PRESSURE SYSTEM WILL PASS UNDER
THE RIDGE AND TOWARDS THE REGION BEFORE DROPPING SE ALONG THE
CALIFORNIA COAST. DEPENDING ON HOW CLOSE TO THE FORECAST AREA IT
PASSES...THE SOUTHERNMOST ZONES MAY SEE SOME LIGHT SHOWERS.
OTHERWISE THANKSGIVING DAY LOOKS TO BE PARTLY TO MOSTLY CLOUDY AND
DRY. TEMPERATURES WILL GRADUALLY TREND TOWARDS SEASONABLE LEVELS
NEXT WEEK.
&&
.AVIATION...VFR. NO CHANGES AS PERSISTENT PATTERN CONTINUES NEXT
24 HRS. GUSTY EAST WINDS CONTINUE UNDER COLD HIGH PRESSURE.
STRONGEST GUSTS WILL BE THROUGH THE COLUMBIA RIVER GORGE WHERE
GUSTS TO 35-40 KT ARE EXPECTED. BREEZY AND GUSTY CONDITIONS ALSO
EXPECTED ALONG THE COAST...ESPECIALLY NEAR COASTAL GAPS.
KPDX AND APPROACHES...VFR. BREEZY EAST WINDS OVERNIGHT. GUSTS
25-35 KT WILL RESUME SHORTLY AFTER DAYBREAK SATURDAY.
&&
.MARINE...A PERSISTENT WEATHER PATTERN OF HIGH PRESSURE INLAND
AND LOWER PRESSURE OFFSHORE WILL CONTINUE TODAY WITH GUSTY
EASTERLY WINDS NEAR THE COASTAL GAPS. HAVE EXTENDED THE SMALL
CRAFT ADVISORY FOR THESE EASTERLY WINDS THROUGH THIS MORNING. THE
WINDS WILL VEER TO THE SOUTH SUNDAY AFTERNOON AS LOWER PRESSURE
APPROACHES FROM THE WEST. SOUTHERLY WINDS WILL PERSIST THROUGH WED
AND FLIRT WITH SMALL CRAFT ADVISORY CONDITIONS AT TIMES. SEAS WILL
REMAIN BETWEEN 3 AND 6 FEET.
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR WINDS UNTIL 10 AM PST THIS MORNING FROM
CAPE SHOALWATER WA TO FLORENCE OR OUT 10 NM- AND FROM CAPE
SHOALWATER WA TO CASCADE HEAD OR 10 TO 60 NM.
&&
MORE WEATHER INFORMATION ONLINE AT...
HTTP://WEATHER.GOV/PORTLAND
INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.PORTLAND.GOV
WWW.TWITTER.COM/NWSPORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM
THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY
REFERRED TO AS THE FORECAST AREA.
AREA FORECAST DISCUSSION...UPDATED
NWS NASHVILLE TN
600 AM CST SAT NOV 23 2013
.UPDATE...FOR 12Z AVIATION DISCUSSION.
&&
.AVIATION...12Z AVAITION DISCUSSION.
UNCERTAINTIES...MVFR CEILING EROSION TIMINGS CKV/BNA AND IFR CSV...ANY
IMPACTS FROM ISO SHWRS THRU 23/16Z. WITH ISO NATURE OF SHWRS PER REGIONAL
RADAR AND NO OBS SITES REPORTING...AND EXPECTING TO CONTINUE THRU 23/16Z...
WILL NOT MENTION. SFC RIDGING INFLUENCES WILL USHER OUT LOW CLOUDS/EROSION
OF LOW LEVEL CEILINGS 23/17Z W TO 23/20Z E. BKN CI CONTINUING THRU 23/23Z
W TO 24/02Z E. CONTINUED BUILDING RIDGING INFLUENCES/DRY NWLY FLOW ALOFT
SHOULD SUPPORT SKC BY 24/06Z. NLY SFC WINDS GUSTS TO 20KTS PER PRESSURE
GRADIENT INFLUENCES WILL SLOWLY WEAKEN TO SUSTAINED 10-12 KTS AS SFC RIDGING
INFLUENCES BUILD INTO MID STATE AFTER 23/23Z.
&&
.PREV DISCUSSION.../ISSUED 330 AM CST SAT NOV 23 2013/
DISCUSSION...
MID LEVEL VORT CENTER STILL POISED TO SLIDE ACROSS THE MID STATE
THIS MORNING. STILL SEEING SOME DESCENT REFLECTIVITY RETURNS TO OUR
WEST ACROSS WESTERN TN AND NRN MS. NUMERICAL GUIDANCE IS QUITE LOW
WITH THE POPS BUT WILL GO AHEAD AND ADHERE TO CURRENT RADAR TRENDS
AND THE HRRR WHICH ALSO SUPPORTS SOME SHOWER ACTIVITY FOR THIS
MORNING. SO...FOR THIS MORNING WILL INCLUDE A SLIGHT CHANCE OF
SHOWERS. HRRR CLEARS THE ACTIVITY FROM THE MID STATE BY 18Z.
PARTIAL CLEARING WILL COMMENCE IN THE AFTERNOON.
CLEARING TO COMMENCE IN EARNEST BY EVENING AS A STRONG COLD SFC HIGH
CONTINUES TO BUILD SOUTHEASTWARD. TEMPS TO TODAY WILL WARM LITTLE AS
THE CAA AT 850 MB RAMPS UP. BY SUNDAY MORNING...SFC HIGH WILL STILL
BE OVER NRN MO. LOW TEMPS WILL REACH THE UPPER TEENS TO LOWER 20S
AND A NORTHERLY 10-15 MPH WIND WILL BE ONGOING. THIS WILL EQUATE TO
WINDCHILL READINGS OF 5 TO 10 DEGREES....QUITE COLD FOR LATE
NOVEMBER.
SUNDAY DURING THE DAY...COLD WEATHER WILL CONTINUE. NORTH WINDS OF
10 TO 15 MPH WILL COMBINE WITH HIGHS IN THE 30S TO PRODUCE WINDCHILL
READINGS ONLY IN THE 20S FOR THE AFTERNOON. COLD INDEED FOR YOUR
SUNDAY.
SUNDAY NIGHT...SOME PARTIAL HIGH CLOUDINESS WILL BEGIN TO RETURN
LATE AS A STORM SYSTEM STARTS DEVELOPING IN THE WESTERN GULF. THIS
SYSTEM WILL TRACK NORTHEAST AND BRING A CHANCE OF PRECIPITATION TO
THE MID STATE MONDAY NIGHT INTO TUESDAY. THE LATEST GFS SOLUTION IS
FURTHER SOUTH WITH THE TRACK AND KEEPS THE BULK OF THE MOISTURE
SOUTH OF MIDDLE TN. THE EURO SOLUTION HOWEVER...IS FURTHER NORTH
WITH THE MOISTURE. THUS...FOR THE FCST...POPS WILL BE KEPT DOWN INTO
THE CHANCE CATEGORY...WITH THE HIGHEST POPS GENERALLY SOUTH. AS FOR
THE PRECIP TYPE MON NIGHT AND TUESDAY...SOUNDINGS STILL SUPPORT A
RAIN AND SLEET MIX. THE DEEP MOISTURE/SUB FREEZING THERMAL
CONNECTION IS NOT IN FOCUS WITH THIS EVENT. THE EURO
SOLUTION...WHICH IS MORE BULLISH WITH THE MOISTURE...IS WARMER MON
NT AND SUPPORTS A MOSTLY RAIN EVENT. GFS...IN CONTRAST...IS DRIER
BUT COLDER. THEREFORE...WITHOUT A POSITIVE MOISTURE/SUBFREEZING
CONNECTION...WILL CONTINUE TO LEAN TOWARD A RAIN/SLEET MIX. THUS...I
WILL BE GOING ABOVE GUIDANCE FOR THE MON NIGHT MINIMUMS.
ON TUESDAY...THE LOWER LEVEL ISOTROPICALLY INDUCED PRECIP WILL BE
PULLING EAST. AT THAT TIME THE FOCUS WILL SHIFT TOWARD THE UPPER
LEVEL SYSTEM. LATEST RUNS BRING THE UPPER LOW EASTWARD ACROSS THE
PANHANDLE OF FL. THIS IS MUCH FURTHER SOUTH THAN PREVIOUS RUNS. WILL
THEREFORE LEAN TOWARD DECREASING THE RAIN/SNOW FCST FROM EARLIER FOR
TUES NT. FURTHERMORE...THE UPPER SYSTEM LOOKS WEAKER IN TERMS OF
MOISTURE EXPANSE AS A TRANSITION TOWARD ANY NEGATIVE TILT
ORIENTATION NOW LOOKS ABSENT.
ON WEDNESDAY...A RETURN TO MOSTLY SUNNY SKIES WILL BE IN STORE. COLD
BUT NOT TOO TERRIBLY COLD FOR THE REST OF THE WEEK. THANKSGIVING
WILL FEATURE MOSTLY CLEAR SKIES...LOWS IN THE 20S HIGHS IN THE 40S.
50 TO 55 DEGREES FOR HIGHS ON FRIDAY...THE BUSIEST SHOPPING DAY OF
THE YEAR...AS AN UPPER RIDGE AXIS DEVELOPS OVER THE SPINE OF THE MS
RIVER.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
31
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
330 AM CST SAT NOV 23 2013
.DISCUSSION...
MID LEVEL VORT CENTER STILL POISED TO SLIDE ACROSS THE MID STATE
THIS MORNING. STILL SEEING SOME DESCENT REFLECTIVITY RETURNS TO OUR
WEST ACROSS WESTERN TN AND NRN MS. NUMERICAL GUIDANCE IS QUITE LOW
WITH THE POPS BUT WILL GO AHEAD AND ADHERE TO CURRENT RADAR TRENDS
AND THE HRRR WHICH ALSO SUPPORTS SOME SHOWER ACTIVITY FOR THIS
MORNING. SO...FOR THIS MORNING WILL INCLUDE A SLIGHT CHANCE OF
SHOWERS. HRRR CLEARS THE ACTIVITY FROM THE MID STATE BY 18Z.
PARTIAL CLEARING WILL COMMENCE IN THE AFTERNOON.
CLEARING TO COMMENCE IN EARNEST BY EVENING AS A STRONG COLD SFC HIGH
CONTINUES TO BUILD SOUTHEASTWARD. TEMPS TO TODAY WILL WARM LITTLE AS
THE CAA AT 850 MB RAMPS UP. BY SUNDAY MORNING...SFC HIGH WILL STILL
BE OVER NRN MO. LOW TEMPS WILL REACH THE UPPER TEENS TO LOWER 20S
AND A NORTHERLY 10-15 MPH WIND WILL BE ONGOING. THIS WILL EQUATE TO
WINDCHILL READINGS OF 5 TO 10 DEGREES....QUITE COLD FOR LATE
NOVEMBER.
SUNDAY DURING THE DAY...COLD WEATHER WILL CONTINUE. NORTH WINDS OF
10 TO 15 MPH WILL COMBINE WITH HIGHS IN THE 30S TO PRODUCE WINDCHILL
READINGS ONLY IN THE 20S FOR THE AFTERNOON. COLD INDEED FOR YOUR
SUNDAY.
SUNDAY NIGHT...SOME PARTIAL HIGH CLOUDINESS WILL BEGIN TO RETURN
LATE AS A STORM SYSTEM STARTS DEVELOPING IN THE WESTERN GULF. THIS
SYSTEM WILL TRACK NORTHEAST AND BRING A CHANCE OF PRECIPITATION TO
THE MID STATE MONDAY NIGHT INTO TUESDAY. THE LATEST GFS SOLUTION IS
FURTHER SOUTH WITH THE TRACK AND KEEPS THE BULK OF THE MOISTURE
SOUTH OF MIDDLE TN. THE EURO SOLUTION HOWEVER...IS FURTHER NORTH
WITH THE MOISTURE. THUS...FOR THE FCST...POPS WILL BE KEPT DOWN INTO
THE CHANCE CATEGORY...WITH THE HIGHEST POPS GENERALLY SOUTH. AS FOR
THE PRECIP TYPE MON NIGHT AND TUESDAY...SOUNDINGS STILL SUPPORT A
RAIN AND SLEET MIX. THE DEEP MOISTURE/SUB FREEZING THERMAL
CONNECTION IS NOT IN FOCUS WITH THIS EVENT. THE EURO
SOLUTION...WHICH IS MORE BULLISH WITH THE MOISTURE...IS WARMER MON
NT AND SUPPORTS A MOSTLY RAIN EVENT. GFS...IN CONTRAST...IS DRIER
BUT COLDER. THEREFORE...WITHOUT A POSITIVE MOISTURE/SUBFREEZING
CONNECTION...WILL CONTINUE TO LEAN TOWARD A RAIN/SLEET MIX. THUS...I
WILL BE GOING ABOVE GUIDANCE FOR THE MON NIGHT MINIMUMS.
ON TUESDAY...THE LOWER LEVEL ISENTROPICALLY INDUCED PRECIP WILL BE
PULLING EAST. AT THAT TIME THE FOCUS WILL SHIFT TOWARD THE UPPER
LEVEL SYSTEM. LATEST RUNS BRING THE UPPER LOW EASTWARD ACROSS THE
PANHANDLE OF FL. THIS IS MUCH FURTHER SOUTH THAN PREVIOUS RUNS. WILL
THEREFORE LEAN TOWARD DECREASING THE RAIN/SNOW FCST FROM EARLIER FOR
TUES NT. FURTHERMORE...THE UPPER SYSTEM LOOKS WEAKER IN TERMS OF
MOISTURE EXPANSE AS A TRANSITION TOWARD ANY NEGATIVE TILT
ORIENTATION NOW LOOKS ABSENT.
ON WEDNESDAY...A RETURN TO MOSTLY SUNNY SKIES WILL BE IN STORE. COLD
BUT NOT TOO TERRIBLY COLD FOR THE REST OF THE WEEK. THANKSGIVING
WILL FEATURE MOSTLY CLEAR SKIES...LOWS IN THE 20S HIGHS IN THE 40S.
50 TO 55 DEGREES FOR HIGHS ON FRIDAY...THE BUSIEST SHOPPING DAY OF
THE YEAR...AS AN UPPER RIDGE AXIS DEVELOPS OVER THE SPINE OF THE MS
RIVER.
&&
.PRELIMINARY POINT TEMPS/POPS...
NASHVILLE 47 22 36 23 / 20 05 0 0
CLARKSVILLE 44 18 33 20 / 20 05 0 0
CROSSVILLE 44 18 31 20 / 20 05 0 0
COLUMBIA 49 22 38 24 / 20 05 0 10
LAWRENCEBURG 50 22 38 24 / 20 05 0 10
WAVERLY 45 19 34 21 / 20 05 0 10
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
21
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
1139 PM CST FRI NOV 22 2013
.UPDATE...
UPDATED FOR THE 06Z AVIATION DISCUSSION.
&&
.PREV DISCUSSION... /ISSUED 743 PM CST FRI NOV 22 2013/
UPDATE...
UPDATED TO REDUCE RAIN CHANCES ACROSS THE EAST THIS EVENING.
DISCUSSION...
CURRENT RADAR TRENDS AND HRRR MODEL RUN INDICATING PRECIPITATION
HOLDING OFF ON DEVELOPMENT AND SPREADING EAST INTO NORTHEAST
MISSISSIPPI UNTIL AFTER 08Z TONIGHT. HAVE REDUCED RAIN CHANCES
ACCORDINGLY. ALL OTHER FORECAST PARAMETERS ARE CURRENTLY ON TRACK.
JAB
&&
.PREV DISCUSSION... /ISSUED 402 PM CST FRI NOV 22 2013/
CURRENTLY...
THE COLD FRONT IS NOW LOCATED FROM EASTERN OHIO...DOWN THROUGH
MIDDLE TENNESSEE...AND INTO CENTRAL MISSISSIPPI. NNW WINDS ARE
RELATIVELY STRONG WITH SUSTAINED 15-20 MPH WITH SOME GUSTS TO 25
MPH. STRONG CAA IS CURRENTLY TAKING PLACE JUST TO THE NORTH OF THE
MID-SOUTH...WITH WIDESPREAD 30S LOCATED ACROSS SOUTHERN MISSOURI.
TEMPERATURES WILL CONTINUE TO COOL THROUGH THIS EVENING WITH LOWS
BOTTOMING OUT IN THE UPPER 30S AND LOWER 40S.
ANOTHER VORT MAX WILL PUSH THROUGH THE MID-SOUTH
OVERNIGHT...TRIGGERING SOME SHOWERS OVER MOST OF THE MID-SOUTH
WITH RAIN CHANCES TAPERING OFF BY MID-MORNING ON SATURDAY. EXTREME
NORTHEAST ARKANSAS MAY SEE A BRIEF CHANCE OF SOME SLEET EARLY IN
THE MORNING ON SATURDAY.
TEMPERATURES DURING THE DAY ON SATURDAY WILL REMAIN COOL...WITH
HIGHS NEAR 50 DEGREES. THE COLDEST AIR THAT WE HAVE SEEN SINCE
LAST WEEK WILL MOVE INTO THE REGION AND STAY PUT THROUGH EARLY
NEXT WEEK. HIGH PRESSURE WILL CENTER OVER THE MID-SOUTH OVERNIGHT
ON SUNDAY...LOWERING TEMPERATURES INTO THE LOW 20S AND EVEN SOME
TEENS IN OUR NORTHERN COUNTIES UNDER CLEAR SKIES.
.SUNDAY THROUGH WEDNESDAY...
COLD AIR WILL REMAIN IN PLACE ON SUNDAY AFTERNOON...WITH HIGHS
ONLY REACHING INTO THE 30S IN WEST TENNESSEE AND NORTHEAST
ARKANSAS...WITH NORTH MISSISSIPPI IN THE LOW 40S. WITH THE COLD
AIR IN PLACE...A CUTOFF LOW WILL BEGIN TO MEANDER INTO THE MID-
SOUTH SUNDAY NIGHT...BRINGING MOISTURE INTO THE MAJORITY OF THE REGION.
MODEL GUIDANCE SUGGESTS THAT THE CUTOFF LOW WILL TAKE A MORE
SOUTHERN ROUTE...WHICH SHOULD DRAW MORE MOISTURE INTO THE REGION
EVEN WITH A DRY AIRMASS IN PLACE. THE ISSUE STILL LIES WITH
TIMING...AS THE GFS MOVES THE SYSTEM THROUGH A TAD BIT QUICKER
THAN THE ECMWF. THE SLOWER TIMING OF THE ECMWF KEEPS THE REGION IN
A WARM SECTOR LONGER...WHICH COULD OFFSET THE COOLING NEEDED FOR
ANY KIND OF MIXED PRECIPITATION.
THE FIRST CHANCE FOR ANY MENTIONABLE FROZEN PRECIPITATION STARTS
MONDAY MORNING FOR THE NORTHERN PARTS OF NORTHEAST ARKANSAS AND
WEST TENNESSEE...BUT ONLY A SLIGHT CHANCE ATTM. MODEL SOUNDINGS
TEMPERATURES ARE RIGHT ON THE EDGE OF BEING JUST COOL ENOUGH TO
POSSIBLY SUPPORT SOME SLEET/FREEZING RAIN. ONCE THE SUN GOES DOWN ON
MONDAY...A LARGER PORTION OF WEST TENNESSEE AND NORTHEAST ARKANSAS
WILL SEE A CHANCE OF SLEET AND OR SNOW DEPENDING ON THE AMOUNT
SATURATION IN THE HIGHER LEVELS OF THE ATMOSPHERE.
ON WEDNESDAY...ANOTHER BRIEF CHANCE OF SNOW WILL BE POSSIBLE IN
THE MORNING ACROSS A LARGER PART OF THE CWA AS THE UPPER LEVEL LOW
EXITS THE REGION. HIGH PRESSURE WILL BUILD INTO THE MID-SOUTH ON
THURSDAY INTO THE WEEKEND WITH TEMPERATURES WARMING INTO THE
UPPER 40S AND LOWER 50S FOR THANKSGIVING DAY.
AC3
&&
.AVIATION...
06Z TAF CYCLE
PRIMARILY MVFR CIGS AND VSBYS WILL PREVAIL THROUGH THE REMAINDER
OF THE NIGHT. LIGHT RAIN SHOWERS WILL CONTINUE TO OVERSPREAD THE
AREA FROM WEST TO EAST. THE GREATEST RAIN POTENTIAL WILL EXIST AT
KTUP...WHERE PREVAILED -RA IN LATEST TAF THROUGH SATURDAY MORNING.
WINDS WILL REMAIN STRONG AND GUSTY FROM THE NORTH BEHIND A COLD
FRONT THAT MOVED ACROSS THE AREA EARLIER TODAY.
LOW CIGS WILL QUICKLY IMPROVE AT ALL TERMINALS SATURDAY MORNING AS
A DRIER AIRMASS MOVES INTO THE REGION. SOUTHWEST FLOW ALOFT WILL
HELP TO MAINTAIN A BROKEN MID LEVEL CLOUD DECK THROUGH MUCH OF THE
DAY BUT CONDITIONS SHOULD REMAIN VFR FROM MID MORNING ONWARD.
GUSTY NORTH WINDS WILL CONTINUE THROUGH SATURDAY INTO SATURDAY
EVENING AT ALL SITES.
JLH
&&
.PRELIMINARY POINT TEMPS/POPS...
MEM 40 48 25 40 / 50 10 0 0
MKL 39 48 20 37 / 30 10 0 0
JBR 36 46 23 36 / 50 0 0 0
TUP 45 52 24 43 / 50 20 10 0
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS AMARILLO TX
1210 PM CST SAT NOV 23 2013
.AVIATION...DISCUSSION FOR 18Z TAFS
FLYING CONDITIONS WILL GENERALLY DETERIORATE THROUGH THE NEXT 12-18
HOURS AS PRECIP CHANCES INCREASE AND CIGS/VSBYS DECREASE. THOUGH
KAMA AND POSSIBLY KDHT COULD BE AFFECTED BY SOME LIGHT SLEET OR SNOW
OVER THE NEXT FEW HOURS...THE MAIN CONCERN WILL BE LATER TONIGHT AS A
MORE INTENSE SNOW BAND WORKS THROUGH THE AREA FROM SW TO NE. HAVE
TIMED OUT BEST CHANCES FOR THIS BAND...BUT TEMPO GROUPS WILL LIKELY
BE NEEDED LATER. WE COULD SEE A LITTLE FREEZING DRIZZLE SUN
MORNING...BUT REFRAINED FROM INCLUDING THIS IN THE TAFS AT THIS TIME
AS IT SHOULD BE PRETTY PATCHY. CIGS WILL BE SLOW TO INCREASE ON
SUN...LIKELY STAYING IFR OR LOW END MVFR THROUGH 18Z.
SIMPSON
&&
.PREV DISCUSSION... /ISSUED 736 AM CST SAT NOV 23 2013/
UPDATE...
LATEST HRRR...TTU-WRF...RUC...NAM AND GFS ALL STILL SHOWING DRIER
WORKING NORTHEAST TO SOUTHWEST ACROSS THE PANHANDLES DURING THE DAY
TODAY WITH A DECREASE IN THE PRECIP. HOWEVER...MODELS NOT PICKING UP
ON PRECIP LIFTING NORTHEAST OUT OF NM AND ERRING ON THE SIDE OF
CAUTION AS ROADS AND HIGHWAYS REMAIN SLICK AND ICY FROM FREEZING RAIN
AND FREEZING DRIZZLE LAST NIGHT. PRECIP COMING OUT OF NM MAY CREATE
ANOTHER ROUND OF FREEZING RAIN...FREEZING DRIZZLE OR SLEET ADDING TO
THE ICY CONDITIONS. DECIDED TO TO ISSUE A WINTER WEATHER ADVISORY
FOR WINTRY PRECIP THROUGH 12Z MONDAY DUE TO THE UNCERTAINITES AND LOW
CONFIDENCE IN THE SHORT RANGE AND HIGH RES MODELS.
UPDATED PUBLIC PRODUCTS HAVE BEEN ISSUED.
SCHNEIDER
PREV DISCUSSION... /ISSUED 522 AM CST SAT NOV 23 2013/
UPDATE...
MOST OF THE PRECIPITATION HAS LEFT THE AREA...THUS THE WINTER WEATHER
WILL BE ALLOWED TO EXPIRE AT THE TOP OF THE HOUR. HOWEVER...ICY ROADS
REMAIN IN THE PANHANDLES...THUS WILL ISSUE AN SPS TO COVER THE SLICK
CONDITIONS THAT WILL REMAIN FOR AT LEAST THE MORNING HOURS.
JOHNSON
AVIATION...
FOR THE 12Z TAFS...CONDITIONS WILL CONTINUE TO IMPROVE THROUGH THE
MORNING HOURS...WITH VFR CONDITIONS EXPECTED AT ALL THREE TAF SITES
FROM 18 TO 00Z. AFTER 00Z...MOISTURE FROM THE NEXT SYSTEM WILL BEGIN
TO STREAM INTO THE REGION...BRINGING LOWER CEILINGS...BR...AND
EVENTUALLY SN. AS WITH YESTERDAY...TEMPERATURES WILL REMAIN BELOW OR
NEAR FREEZING ALL DAY...THUS ANY BR THAT DEVELOPS CARRIES THE ADDED
THREAT OF ICING.
JOHNSON
PREV DISCUSSION... /ISSUED 409 AM CST SAT NOV 23 2013/
DISCUSSION...
CLOSED UPPER LOW OVER SOUTHERN CALIFORNIA AND NORTHERN BAJA WILL
BEGIN TO EJECT SLOWLY EAST TODAY...MOVING ACROSS THE SOUTHWESTERN
STATES BY 12Z SUNDAY...AND THEN ACROSS THE SOUTHERN ROCKIES SUNDAY
NIGHT. SHORTWAVE RIDGE AHEAD OF THE UPPER LOW WILL REMAIN OVER THE
FORECAST AREA TODAY AND THEN WILL SHIFT EAST AWAY FROM THE PANHANDLES
SUNDAY. ANY WINTRY PRECIPITATION TODAY WILL BE RATHER LIGHT AND LOW
CONFIDENCE PREVAILS ON PRECIP TYPE. FREEZING DRIZZLE AND LIGHT
FREEZING RAIN HAS ALREADY GLAZED ROADS AND HIGHWAYS IN THE FORECAST
AREA SINCE ABOUT 05Z TO 10Z SATURDAY BUT MOVING NORTHEAST OUT OF THE
FORECAST AREA. THE LATEST HRRR SHOWING DRYING TREND THROUGH THE DAY
TODAY UNTIL THE NEXT ROUND OF PRECIP MOVES INTO THE PANHANDLES AFTER
00Z SUNDAY. WILL HOLD OFF ON ANY ADVISORIES...WATCHES OR WARNINGS
TODAY AS THE CURRENT WINTER WEATHER ADVISORY SET TO EXPIRE AT 12Z
TODAY. BEST CHANCES FOR ANOTHER ROUND OF FREEZING AND OR FROZEN
PRECIPITATION...MAINLY SNOW AND SLEET...WILL OCCUR TONIGHT THROUGH
SUNDAY AND SUNDAY NIGHT AS THE LEADING SHORTWAVE ASSOCIATED WITH THE
UPPER LOW TRACKS EAST OUT OF THE FOUR CORNERS REGION AND SOUTHERN
ROCKIES BY 06Z SUNDAY WITH THE MAIN SHORTWAVE AFFECTING THE
PANHANDLES BY 00Z MONDAY. NAM STILL OVERLY BULLISH ON POPS AND QPF
WHILE THE GFS AND ECMWF DIFFER ON TIMING AND TRACK OF THE UPPER LOW.
THE GFS IS FASTER THAN THE ECMWF AND FURTHER SOUTH WITH THE CLOSED
UPPER LOW. LOW CONFIDENCE IN THE MEDIUM RANGE MODELS BUT LEAN TOWARD
THE ECMWF SOLUTION.
BOTH THE ECMWF AND GFS SHUTTING OFF THE PRECIP BY LATE MONDAY AS THE
CLOSED UPPER LOW DIGS SOUTH OF THE PANHANDLES BY 00Z TUESDAY AND BEST
LIFT WELL SOUTH AND EAST OF THE FORECAST AREA. DRIER AIR TO WORK INTO
THE PANHANDLES BY MONDAY NIGHT ALLOWING FOR CLEARING SKIES BY 12Z
TUESDAY. SLOWLY MODERATING TEMPS AND DRY TUESDAY THROUGH THE END OF
NEXT WEEK AS LEE SURFACE TROUGH DEVELOPS BY THE MIDDLE OF NEXT WEEK
AND WARMER SOUTHERLY FLOW PREVAILS. ANOTHER COLD FRONT MAY PUSH
THROUGH THE PANHANDLES BY NEXT SATURDAY.
SCHNEIDER
FIRE WEATHER...
NO ELEVATED OR CRITICAL FIRE WEATHER CONDITIONS ARE EXPECTED TODAY
THROUGH LATE NEXT WEEK.
SCHNEIDER
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...WINTER WEATHER ADVISORY UNTIL 6 AM CST MONDAY FOR THE FOLLOWING
ZONES: ARMSTRONG...CARSON...COLLINGSWORTH...DALLAM...DEAF
SMITH...DONLEY...GRAY...HANSFORD...HARTLEY...HEMPHILL...
HUTCHINSON...LIPSCOMB...MOORE...OCHILTREE...OLDHAM...
POTTER...RANDALL...ROBERTS...SHERMAN...WHEELER.
OK...WINTER WEATHER ADVISORY UNTIL 6 AM CST MONDAY FOR THE FOLLOWING
ZONES: BEAVER...CIMARRON...TEXAS.
&&
$$
09/08
AREA FORECAST DISCUSSION...UPDATED
NWS AMARILLO TX
736 AM CST SAT NOV 23 2013
.UPDATE...
LATEST HRRR...TTU-WRF...RUC...NAM AND GFS ALL STILL SHOWING DRIER
WORKING NORTHEAST TO SOUTHWEST ACROSS THE PANHANDLES DURING THE DAY
TODAY WITH A DECREASE IN THE PRECIP. HOWEVER...MODELS NOT PICKING UP
ON PRECIP LIFTING NORTHEAST OUT OF NM AND ERRING ON THE SIDE OF
CAUTION AS ROADS AND HIGHWAYS REMAIN SLICK AND ICY FROM FREEZING RAIN
AND FREEZING DRIZZLE LAST NIGHT. PRECIP COMING OUT OF NM MAY CREATE
ANOTHER ROUND OF FREEZING RAIN...FREEZING DRIZZLE OR SLEET ADDING TO
THE ICY CONDITIONS. DECIDED TO TO ISSUE A WINTER WEATHER ADVISORY
FOR WINTRY PRECIP THROUGH 12Z MONDAY DUE TO THE UNCERTAINITES AND LOW
CONFIDENCE IN THE SHORT RANGE AND HIGH RES MODELS.
UPDATED PUBLIC PRODUCTS HAVE BEEN ISSUED.
SCHNEIDER
&&
.PREV DISCUSSION... /ISSUED 522 AM CST SAT NOV 23 2013/
UPDATE...
MOST OF THE PRECIPITATION HAS LEFT THE AREA...THUS THE WINTER WEATHER
WILL BE ALLOWED TO EXPIRE AT THE TOP OF THE HOUR. HOWEVER...ICY ROADS
REMAIN IN THE PANHANDLES...THUS WILL ISSUE AN SPS TO COVER THE SLICK
CONDITIONS THAT WILL REMAIN FOR AT LEAST THE MORNING HOURS.
JOHNSON
AVIATION...
FOR THE 12Z TAFS...CONDITIONS WILL CONTINUE TO IMPROVE THROUGH THE
MORNING HOURS...WITH VFR CONDITIONS EXPECTED AT ALL THREE TAF SITES
FROM 18 TO 00Z. AFTER 00Z...MOISTURE FROM THE NEXT SYSTEM WILL BEGIN
TO STREAM INTO THE REGION...BRINGING LOWER CEILINGS...BR...AND
EVENTUALLY SN. AS WITH YESTERDAY...TEMPERATURES WILL REMAIN BELOW OR
NEAR FREEZING ALL DAY...THUS ANY BR THAT DEVELOPS CARRIES THE ADDED
THREAT OF ICING.
JOHNSON
PREV DISCUSSION... /ISSUED 409 AM CST SAT NOV 23 2013/
DISCUSSION...
CLOSED UPPER LOW OVER SOUTHERN CALIFORNIA AND NORTHERN BAJA WILL
BEGIN TO EJECT SLOWLY EAST TODAY...MOVING ACROSS THE SOUTHWESTERN
STATES BY 12Z SUNDAY...AND THEN ACROSS THE SOUTHERN ROCKIES SUNDAY
NIGHT. SHORTWAVE RIDGE AHEAD OF THE UPPER LOW WILL REMAIN OVER THE
FORECAST AREA TODAY AND THEN WILL SHIFT EAST AWAY FROM THE PANHANDLES
SUNDAY. ANY WINTRY PRECIPITATION TODAY WILL BE RATHER LIGHT AND LOW
CONFIDENCE PREVAILS ON PRECIP TYPE. FREEZING DRIZZLE AND LIGHT
FREEZING RAIN HAS ALREADY GLAZED ROADS AND HIGHWAYS IN THE FORECAST
AREA SINCE ABOUT 05Z TO 10Z SATURDAY BUT MOVING NORTHEAST OUT OF THE
FORECAST AREA. THE LATEST HRRR SHOWING DRYING TREND THROUGH THE DAY
TODAY UNTIL THE NEXT ROUND OF PRECIP MOVES INTO THE PANHANDLES AFTER
00Z SUNDAY. WILL HOLD OFF ON ANY ADVISORIES...WATCHES OR WARNINGS
TODAY AS THE CURRENT WINTER WEATHER ADVISORY SET TO EXPIRE AT 12Z
TODAY. BEST CHANCES FOR ANOTHER ROUND OF FREEZING AND OR FROZEN
PRECIPITATION...MAINLY SNOW AND SLEET...WILL OCCUR TONIGHT THROUGH
SUNDAY AND SUNDAY NIGHT AS THE LEADING SHORTWAVE ASSOCIATED WITH THE
UPPER LOW TRACKS EAST OUT OF THE FOUR CORNERS REGION AND SOUTHERN
ROCKIES BY 06Z SUNDAY WITH THE MAIN SHORTWAVE AFFECTING THE
PANHANDLES BY 00Z MONDAY. NAM STILL OVERLY BULLISH ON POPS AND QPF
WHILE THE GFS AND ECMWF DIFFER ON TIMING AND TRACK OF THE UPPER LOW.
THE GFS IS FASTER THAN THE ECMWF AND FURTHER SOUTH WITH THE CLOSED
UPPER LOW. LOW CONFIDENCE IN THE MEDIUM RANGE MODELS BUT LEAN TOWARD
THE ECMWF SOLUTION.
BOTH THE ECMWF AND GFS SHUTTING OFF THE PRECIP BY LATE MONDAY AS THE
CLOSED UPPER LOW DIGS SOUTH OF THE PANHANDLES BY 00Z TUESDAY AND BEST
LIFT WELL SOUTH AND EAST OF THE FORECAST AREA. DRIER AIR TO WORK INTO
THE PANHANDLES BY MONDAY NIGHT ALLOWING FOR CLEARING SKIES BY 12Z
TUESDAY. SLOWLY MODERATING TEMPS AND DRY TUESDAY THROUGH THE END OF
NEXT WEEK AS LEE SURFACE TROUGH DEVELOPS BY THE MIDDLE OF NEXT WEEK
AND WARMER SOUTHERLY FLOW PREVAILS. ANOTHER COLD FRONT MAY PUSH
THROUGH THE PANHANDLES BY NEXT SATURDAY.
SCHNEIDER
FIRE WEATHER...
NO ELEVATED OR CRITICAL FIRE WEATHER CONDITIONS ARE EXPECTED TODAY
THROUGH LATE NEXT WEEK.
SCHNEIDER
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...WINTER WEATHER ADVISORY UNTIL 6 AM CST MONDAY FOR THE FOLLOWING
ZONES: ARMSTRONG...CARSON...COLLINGSWORTH...DALLAM...DEAF
SMITH...DONLEY...GRAY...HANSFORD...HARTLEY...HEMPHILL...
HUTCHINSON...LIPSCOMB...MOORE...OCHILTREE...OLDHAM...
POTTER...RANDALL...ROBERTS...SHERMAN...WHEELER.
OK...WINTER WEATHER ADVISORY UNTIL 6 AM CST MONDAY FOR THE FOLLOWING
ZONES: BEAVER...CIMARRON...TEXAS.
&&
$$
16/11
AREA FORECAST DISCUSSION...UPDATED
NWS AMARILLO TX
522 AM CST SAT NOV 23 2013
.UPDATE...
MOST OF THE PRECIPITATION HAS LEFT THE AREA...THUS THE WINTER WEATHER
WILL BE ALLOWED TO EXPIRE AT THE TOP OF THE HOUR. HOWEVER...ICY ROADS
REMAIN IN THE PANHANDLES...THUS WILL ISSUE AN SPS TO COVER THE SLICK
CONDITIONS THAT WILL REMAIN FOR AT LEAST THE MORNING HOURS.
JOHNSON
&&
.AVIATION...
FOR THE 12Z TAFS...CONDITIONS WILL CONTINUE TO IMPROVE THROUGH THE
MORNING HOURS...WITH VFR CONDITIONS EXPECTED AT ALL THREE TAF SITES
FROM 18 TO 00Z. AFTER 00Z...MOISTURE FROM THE NEXT SYSTEM WILL BEGIN
TO STREAM INTO THE REGION...BRINGING LOWER CEILINGS...BR...AND
EVENTUALLY SN. AS WITH YESTERDAY...TEMPERATURES WILL REMAIN BELOW OR
NEAR FREEZING ALL DAY...THUS ANY BR THAT DEVELOPS CARRIES THE ADDED
THREAT OF ICING.
JOHNSON
&&
.PREV DISCUSSION... /ISSUED 409 AM CST SAT NOV 23 2013/
DISCUSSION...
CLOSED UPPER LOW OVER SOUTHERN CALIFORNIA AND NORTHERN BAJA WILL
BEGIN TO EJECT SLOWLY EAST TODAY...MOVING ACROSS THE SOUTHWESTERN
STATES BY 12Z SUNDAY...AND THEN ACROSS THE SOUTHERN ROCKIES SUNDAY
NIGHT. SHORTWAVE RIDGE AHEAD OF THE UPPER LOW WILL REMAIN OVER THE
FORECAST AREA TODAY AND THEN WILL SHIFT EAST AWAY FROM THE PANHANDLES
SUNDAY. ANY WINTRY PRECIPITATION TODAY WILL BE RATHER LIGHT AND LOW
CONFIDENCE PREVAILS ON PRECIP TYPE. FREEZING DRIZZLE AND LIGHT
FREEZING RAIN HAS ALREADY GLAZED ROADS AND HIGHWAYS IN THE FORECAST
AREA SINCE ABOUT 05Z TO 10Z SATURDAY BUT MOVING NORTHEAST OUT OF THE
FORECAST AREA. THE LATEST HRRR SHOWING DRYING TREND THROUGH THE DAY
TODAY UNTIL THE NEXT ROUND OF PRECIP MOVES INTO THE PANHANDLES AFTER
00Z SUNDAY. WILL HOLD OFF ON ANY ADVISORIES...WATCHES OR WARNINGS
TODAY AS THE CURRENT WINTER WEATHER ADVISORY SET TO EXPIRE AT 12Z
TODAY. BEST CHANCES FOR ANOTHER ROUND OF FREEZING AND OR FROZEN
PRECIPITATION...MAINLY SNOW AND SLEET...WILL OCCUR TONIGHT THROUGH
SUNDAY AND SUNDAY NIGHT AS THE LEADING SHORTWAVE ASSOCIATED WITH THE
UPPER LOW TRACKS EAST OUT OF THE FOUR CORNERS REGION AND SOUTHERN
ROCKIES BY 06Z SUNDAY WITH THE MAIN SHORTWAVE AFFECTING THE
PANHANDLES BY 00Z MONDAY. NAM STILL OVERLY BULLISH ON POPS AND QPF
WHILE THE GFS AND ECMWF DIFFER ON TIMING AND TRACK OF THE UPPER LOW.
THE GFS IS FASTER THAN THE ECMWF AND FURTHER SOUTH WITH THE CLOSED
UPPER LOW. LOW CONFIDENCE IN THE MEDIUM RANGE MODELS BUT LEAN TOWARD
THE ECMWF SOLUTION.
BOTH THE ECMWF AND GFS SHUTTING OFF THE PRECIP BY LATE MONDAY AS THE
CLOSED UPPER LOW DIGS SOUTH OF THE PANHANDLES BY 00Z TUESDAY AND BEST
LIFT WELL SOUTH AND EAST OF THE FORECAST AREA. DRIER AIR TO WORK INTO
THE PANHANDLES BY MONDAY NIGHT ALLOWING FOR CLEARING SKIES BY 12Z
TUESDAY. SLOWLY MODERATING TEMPS AND DRY TUESDAY THROUGH THE END OF
NEXT WEEK AS LEE SURFACE TROUGH DEVELOPS BY THE MIDDLE OF NEXT WEEK
AND WARMER SOUTHERLY FLOW PREVAILS. ANOTHER COLD FRONT MAY PUSH
THROUGH THE PANHANDLES BY NEXT SATURDAY.
SCHNEIDER
FIRE WEATHER...
NO ELEVATED OR CRITICAL FIRE WEATHER CONDITIONS ARE EXPECTED TODAY
THROUGH LATE NEXT WEEK.
SCHNEIDER
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...WINTER WEATHER ADVISORY UNTIL 6 AM CST EARLY THIS MORNING FOR
THE FOLLOWING ZONES: DALLAM...HANSFORD...HARTLEY...MOORE...
OLDHAM...SHERMAN.
OK...WINTER WEATHER ADVISORY UNTIL 6 AM CST EARLY THIS MORNING FOR
THE FOLLOWING ZONES: CIMARRON...TEXAS.
&&
$$
16/11
AREA FORECAST DISCUSSION...CORRECTED
NWS AMARILLO TX
409 AM CST SAT NOV 23 2013
.DISCUSSION...
CLOSED UPPER LOW OVER SOUTHERN CALIFORNIA AND NORTHERN BAJA WILL
BEGIN TO EJECT SLOWLY EAST TODAY...MOVING ACROSS THE SOUTHWESTERN
STATES BY 12Z SUNDAY...AND THEN ACROSS THE SOUTHERN ROCKIES SUNDAY
NIGHT. SHORTWAVE RIDGE AHEAD OF THE UPPER LOW WILL REMAIN OVER THE
FORECAST AREA TODAY AND THEN WILL SHIFT EAST AWAY FROM THE PANHANDLES
SUNDAY. ANY WINTRY PRECIPITATION TODAY WILL BE RATHER LIGHT AND LOW
CONFIDENCE PREVAILS ON PRECIP TYPE. FREEZING DRIZZLE AND LIGHT
FREEZING RAIN HAS ALREADY GLAZED ROADS AND HIGHWAYS IN THE FORECAST
AREA SINCE ABOUT 05Z TO 10Z SATURDAY BUT MOVING NORTHEAST OUT OF THE
FORECAST AREA. THE LATEST HRRR SHOWING DRYING TREND THROUGH THE DAY
TODAY UNTIL THE NEXT ROUND OF PRECIP MOVES INTO THE PANHANDLES AFTER
00Z SUNDAY. WILL HOLD OFF ON ANY ADVISORIES...WATCHES OR WARNINGS
TODAY AS THE CURRENT WINTER WEATHER ADVISORY SET TO EXPIRE AT 12Z
TODAY. BEST CHANCES FOR ANOTHER ROUND OF FREEZING AND OR FROZEN
PRECIPITATION...MAINLY SNOW AND SLEET...WILL OCCUR TONIGHT THROUGH
SUNDAY AND SUNDAY NIGHT AS THE LEADING SHORTWAVE ASSOCIATED WITH THE
UPPER LOW TRACKS EAST OUT OF THE FOUR CORNERS REGION AND SOUTHERN
ROCKIES BY 06Z SUNDAY WITH THE MAIN SHORTWAVE AFFECTING THE
PANHANDLES BY 00Z MONDAY. NAM STILL OVERLY BULLISH ON POPS AND QPF
WHILE THE GFS AND ECMWF DIFFER ON TIMING AND TRACK OF THE UPPER LOW.
THE GFS IS FASTER THAN THE ECMWF AND FURTHER SOUTH WITH THE CLOSED
UPPER LOW. LOW CONFIDENCE IN THE MEDIUM RANGE MODELS BUT LEAN TOWARD
THE ECMWF SOLUTION.
BOTH THE ECMWF AND GFS SHUTTING OFF THE PRECIP BY LATE MONDAY AS THE
CLOSED UPPER LOW DIGS SOUTH OF THE PANHANDLES BY 00Z TUESDAY AND BEST
LIFT WELL SOUTH AND EAST OF THE FORECAST AREA. DRIER AIR TO WORK INTO
THE PANHANDLES BY MONDAY NIGHT ALLOWING FOR CLEARING SKIES BY 12Z
TUESDAY. SLOWLY MODERATING TEMPS AND DRY TUESDAY THROUGH THE END OF
NEXT WEEK AS LEE SURFACE TROUGH DEVELOPS BY THE MIDDLE OF NEXT WEEK
AND WARMER SOUTHERLY FLOW PREVAILS. ANOTHER COLD FRONT MAY PUSH
THROUGH THE PANHANDLES BY NEXT SATURDAY.
SCHNEIDER
&&
.FIRE WEATHER...
NO ELEVATED OR CRITICAL FIRE WEATHER CONDITIONS ARE EXPECTED TODAY
THROUGH LATE NEXT WEEK.
SCHNEIDER
&&
.PRELIMINARY POINT TEMPS/POPS...
AMARILLO TX 31 17 25 22 34 / 30 70 60 30 20
BEAVER OK 31 18 28 23 37 / 10 40 50 30 10
BOISE CITY OK 31 18 28 21 39 / 20 50 50 20 10
BORGER TX 33 21 29 23 38 / 20 60 60 30 20
BOYS RANCH TX 32 20 26 24 36 / 30 70 60 30 20
CANYON TX 31 18 25 22 34 / 30 70 60 30 20
CLARENDON TX 33 20 25 25 36 / 30 60 60 40 20
DALHART TX 31 17 26 20 38 / 30 60 50 20 20
GUYMON OK 31 18 29 23 40 / 20 50 50 20 10
HEREFORD TX 31 18 27 21 36 / 40 70 60 30 20
LIPSCOMB TX 32 17 29 26 37 / 10 50 60 30 10
PAMPA TX 32 18 24 23 33 / 20 60 60 30 20
SHAMROCK TX 34 21 27 25 36 / 20 60 60 40 20
WELLINGTON TX 34 21 27 24 36 / 20 60 70 40 20
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...WINTER WEATHER ADVISORY UNTIL 6 AM CST EARLY THIS MORNING FOR
THE FOLLOWING ZONES: DALLAM...HANSFORD...HARTLEY...MOORE...
OLDHAM...SHERMAN.
OK...WINTER WEATHER ADVISORY UNTIL 6 AM CST EARLY THIS MORNING FOR
THE FOLLOWING ZONES: CIMARRON...TEXAS.
&&
$$
16/11
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
933 PM CST SUN NOV 24 2013
.UPDATE...
ISSUED AT 933 PM CST SUN NOV 24 2013
THE MAIN FOCUS TONIGHT HAS BEEN ON THE PRECIPITATION TYPE AND
CHANCES OVERNIGHT INTO TOMORROW MORNING. CURRENTLY...THERE IS ONE
LEAD MID LEVEL SHORTWAVE TROUGH DROPPING SOUTH ACROSS CENTRAL
MINNESOTA AND NORTHERN WISCONSIN WITH ANOTHER SYSTEM IN THE
CENTRAL PLAINS. RADAR RETURNS WITH THE MN/WI TROUGH DO NOT APPEAR
TO BE REACHING THE GROUND DUE TO SOME DRY LOW TO MID LEVEL AIR
THAT IS IN PLACE ACCORDING TO 25.00Z MPX/GRB/ABR RAOBS. THE RADAR
RETURNS IN SOUTHWEST IOWA ALSO DO NOT APPEAR TO BE REACHING THE
GROUND AS WELL THANKS TO THIS DRY LOW LEVEL AIR. SO...WHILE CLOUD
COVER WILL BE ON THE INCREASE...IT APPEARS THAT THE REST OF THE
EVENING WILL BE DRY.
THE MAIN CHANCES FOR ANY PRECIPITATION LOOKS TO BE BETWEEN 3AM AND
9AM TOMORROW MORNING AS THESE TWO SYSTEMS CONVERGE ON THE AREA.
HAD HOPED TO HAVE A BETTER HANDLE ON WHETHER THERE WILL BE ICE
PRESENT AS THE LIFT COMES IN...BUT THE PAST FEW RUNS OF THE RAP
HAVE GONE BACK AND FORTH ON WHETHER THERE WILL BE ANY ICE. THIS
LEADS TO CONFIDENCE NOT BEING HIGH ENOUGH TO MOVE FORWARD ON A
POTENTIAL ADVISORY FOR FREEZING DRIZZLE SINCE THE POSSIBILITY IS
THERE THAT IT WOULD JUST BE A BRIEF PERIOD OF LIGHT SNOW.
OTHERWISE...WINDS HAVE REMAINED GUSTY THROUGHOUT THE REGION AS THE
PRESSURE GRADIENT IS STILL VERY TIGHT BETWEEN THE RETREATING HIGH
OVER THE OHIO RIVER VALLEY AND THE APPROACHING TROUGH IN THE
NORTHERN PLAINS.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 201 PM CST SUN NOV 24 2013
MAIN SHORT TERM FORECAST CONCERN IS ON PRECIPITATION CHANCES LATER
TONIGHT...ALONG WITH HOW MUCH AND POTENTIAL FOR FREEZING DRIZZLE.
CURRENTLY AS OF 20Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED RIDGING ALONG THE WEST COAST OF NORTH AMERICA...SUBTROPICAL
STREAM TROUGH OVER ARIZONA...AND NORTHERN STREAM TROUGHING FROM
CENTRAL CANADA INTO NEW ENGLAND. WITHIN THIS TROUGHING...A FAIRLY
POTENT SHORTWAVE WAS SEEN DIVING SOUTHEAST THROUGH SASKATCHEWAN.
AHEAD OF THIS TROUGH...VAD WIND PROFILES DEPICT 30-45 KT 925MB WINDS
ACROSS THE EASTERN DAKOTAS AND MINNESOTA. THESE WINDS HAVE BEEN
ADVECTING WARMER AIR TOWARDS THE FORECAST AREA...WITH 925MB TEMPS
NOW PER RAP ANALYSIS AT -7 TO -12C...COMPARED TO -12 TO -14C AT 12Z.
AIRMASS REMAINS RELATIVELY DRY...THOUGH...WITH PRECIPITABLE WATER
VALUES JUST BELOW 0.25 INCH ACROSS THE UPPER MIDWEST. UPSTREAM IN
THE WAKE OF THE SHORTWAVE...ANOTHER ARCTIC AIR SURGE WAS BREWING
ACROSS THE NORTHWEST TERRITORIES WHERE TEMPERATURES ARE SITTING IN
THE SINGLE DIGITS AND TEENS ABOVE ZERO.
MODELS ARE IN GOOD AGREEMENT SLIDING THE POTENT SHORTWAVE OVER
SASKATCHEWAN SOUTHEAST INTO NORTHERN PORTIONS OF MN...WI AND MI
MONDAY MORNING...THEN HEADING OFF TO EASTERN ONTARIO DURING THE
AFTERNOON. AS THE SHORTWAVE APPROACHES TONIGHT...SFC/925/850MB WINDS
ALL INCREASE OVER THE FORECAST AREA...SETTING UP FOR A MUCH WARMER
NIGHT. IN ADDITION...THESE WINDS WILL ADVECT IN A TONGUE OF
RELATIVELY HIGHER MOISTURE FROM WESTERN KS AND EASTERN COLORADO...AS
WELL AS FROM UP IN SOUTHERN MANITOBA...NOTED BY PRECIPITABLE WATER
CLIMBING TO AROUND 0.5 INCH. THE HIGHEST PRECIPITABLE WATER IS
CONFINED TO NORTHEAST IOWA AND SOUTHERN WI WHICH WOULD THEREFORE BE
THE GREATEST CONCERN FOR PRECIPITATION. ALBEIT...THE GENERAL LOW
AMOUNT OF PRECIPITABLE WATER WILL LIKELY LIMIT THE AMOUNT OF
PRECIPITATION. REGARDING LIFT...280-290K ISENTROPIC SURFACES DEPICT
AN INCREASE OF NET ADIABATIC OMEGA ACROSS THE FORECAST AREA BETWEEN
06 AND 12Z...THEN SLIDES OFF TO THE SOUTHEAST. GENERAL MODEL
CONSENSUS HAS BEEN HOLDING STEADY SUGGESTING PRECIPITATION BREAKING
OUT ACROSS NORTHEAST IOWA LATE TONIGHT...THEN SPREADING INTO
SOUTHERN AND PERHAPS CENTRAL WISCONSIN MONDAY MORNING. SINCE
SATURATION OCCURS FROM THE LOW TO MID LEVELS OF THE ATMOSPHERE...THE
PRECIPITATION TYPE SHOULD BE MOSTLY SNOW...BUT CANNOT RULE OUT SOME
FREEZING DRIZZLE POSSIBLE EITHER AT THE ONSET OR ON THE NORTH SIDE
OF THE DEEPER MOISTURE. ANOTHER CONCERN IS PRECIPITATION BREAKING
OUT ALONG THE POTENT SHORTWAVES WARM FRONT. 24.12Z GFS/HIRESARW AND
24.15Z SREF ALL SUGGEST THAT AS THE FRONT RUNS INTO LOW LEVEL
STRATUS WHICH DEVELOPED LATE TONIGHT AHEAD OF IT...VERTICAL MOTION
WITH THE FRONT CAN PRODUCE LIGHT PRECIPITATION. THIS WOULD APPEAR TO
BE THE BEST CHANCE TO SEE FREEZING DRIZZLE. MUCH OF THE FORECAST
AREA WOULD HAVE A CONCERN FOR THIS DEVELOPING...INCLUDING NORTHEAST
IA AND SOUTHERN WI WHEN THE SNOW THERE DEPARTS.
GIVEN THAT THE PROBABILITY OF FREEZING DRIZZLE IS LOW AT THIS
TIME...ON THE ORDER OF 20 TO MAYBE 30 PERCENT...HAVE NOT ISSUED ANY
WINTER WEATHER ADVISORIES. FURTHER SHIFTS MAY NEED TO ISSUE
THEM...THOUGH...IF FREEZING DRIZZLE LOOKS MORE LIKELY TO OCCUR.
TEMPERATURE WISE...WE SHOULD SEE TEMPERATURES HOLD EITHER NEARLY
STEADY AND LIKELY RISE AFTER MIDNIGHT AS THE BREEZY SOUTH WINDS
BRING IN WARMER AIR AT THE SURFACE. THERE IS POTENTIAL FOR SOME
CLEARING MONDAY AFTERNOON...WHICH WITH 925MB TEMPS WARMING TO -2 TO -
4C IN THE AFTERNOON...HIGHS SHOULD CLIMB INTO THE 30S IN MOST
LOCATIONS.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 201 PM CST SUN NOV 24 2013
FOCUS OF THE LONG TERM PERIOD IS ON AN ARCTIC COOL SHOT SLATED FOR
TUESDAY INTO WEDNESDAY...AND ANY POSSIBLE PRECIPITATION THURSDAY
INTO THE WEEKEND.
MODELS DEPICT ANOTHER POTENT SHORTWAVE DROPPING OUT OF THE NORTHWEST
TERRITORIES AND DOWN INTO THE FORECAST AREA ON TUESDAY. THIS POTENT
SHORTWAVE REALLY HELPS TO BRING DOWN THE ARCTIC AIR OBSERVED UP
THERE. AT THE SAME TIME...WITH THE ARCTIC COLD FRONTAL PASSAGE
OCCURRING IN THE MORNING...LOW LEVEL MOISTURE GETS TRAPPED. THIS
MOISTURE COMBINED WITH DAYTIME HEATING WILL MANIFEST ITSELF INTO A
FAIRLY WIDESPREAD STRATUS DECK. STEEP LOW LEVEL LAPSE RATES ALONG
WITH THE STRATUS DECK BEING IN THE DENDRITIC GROWTH ZONE IS LIKELY
TO LEAD TO FLURRIES AT A MINIMUM...AND WOULD NOT BE SURPRISED IF
SOME LOW CHANCES OF PRECIPITATION WILL NEED TO BE ADDED.
WITH THE ARCTIC COLD FRONTAL PASSAGE TUESDAY MORNING...EXPECT
TEMPERATURES TO NOT RISE MUCH AND IF ANYTHING WILL LIKELY FALL
DURING THE AFTERNOON HOURS. 925MB TEMPS FALL TO -12C BY 00Z
WEDNESDAY AND TO AROUND -14C BY 12Z WEDNESDAY. THERE IS A CONTINUING
NORTHWEST BREEZE THROUGH THIS PERIOD WHICH WILL TEMPER A BIT ON HOW
COLD WE GET TUESDAY NIGHT...AND LEANED MORE TOWARDS THE MET GUIDANCE
FOR LOWS. ON THE FLIP SIDE...EXPECT COLDER WIND CHILLS BECAUSE OF
THE BREEZE. SOME MODERATION TAKES PLACE IN 925MB TEMPS ON WEDNESDAY
WITH SUN SO THAT TEMPERATURES CAN CLIMB BACK INTO THE LOW TO MID
20S.
THE UPPER FLOW FROM THANKSGIVING AND BEYOND LOOKS TO CHANGE...GOING
FROM THE NORTHWESTERLY PATTERN WE HAVE BEEN IN RECENTLY TOWARDS MORE
ZONAL. THERE ARE EVEN HINTS IN THE 24.12Z ECMWF OF THE FLOW BACKING
SOUTHWESTERLY EARLY NEXT WEEK. THIS PATTERN CHANGE WILL HELP
DISLODGE SOME OF THE COLD AIR...THUS FOLLOWED A CONSENSUS FORECAST
DEPICTING A GRADUAL MODERATING TREND FOR TEMPERATURES. REGARDING
PRECIPITATION CHANCES...DURING THE PATTERN CHANGE...THERE ARE
SHORTWAVE TROUGHS TRAVERSING ACROSS NORTHERN MN INTO UPPER MI ON
THANKSGIVING AND ON SATURDAY. RIGHT NOW BASED ON THE TRACK WOULD
SUGGEST THE BETTER CHANCES FOR PRECIPITATION WOULD STAY NORTH OF THE
FORECAST AREA. HOWEVER...THAT SATURDAY SHORTWAVE TROUGH APPEARS TO
TAKE A BIT FARTHER SOUTH TRACK COMPARED TO THE ONE ON
THANKSGIVING...THUS 20 PERCENT CHANCES OF SNOW ARE IN THE
FORECAST FOR BOTH SATURDAY AND SATURDAY NIGHT. FRIDAY AND SUNDAY
APPEAR DRY AT THIS TIME BETWEEN SHORTWAVE TROUGHS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 559 PM CST SUN NOV 24 2013
WINDY CONDITIONS TO CONTINUE OVERNIGHT WITH A PERIOD OF FREEZING
DRIZZLE POSSIBLE TOMORROW MORNING. SUSTAINED WINDS WILL REMAIN
STRONG OVERNIGHT WITH SOME LOW LEVEL WIND SHEAR EXPECTED TO
DEVELOP QUICKLY THIS EVENING. WINDS WILL INCREASE TO BETWEEN
50-60KTS AROUND 2KFT WHILE BEING AROUND 15-20KTS AT THE SURFACE.
LOW LEVEL MOISTURE WILL START TO INCREASE TOMORROW MORNING AS TWO
SYSTEMS MOVE INTO THE REGION. THE MAIN CHANCES FOR SNOW APPEAR TO
BE FURTHER TO THE SOUTH WHERE THE MOISTURE/LIFT IS DEEPER WITH
ABOUT A 2-6 HOUR PERIOD OF FREEZING DRIZZLE POSSIBLE AT THE TAF
SITES. FLIGHT CONDITIONS WILL LIKELY DROP TO MVFR/IFR AS THIS
DRIZZLE BEGINS...BUT THEN SHOULD QUICKLY IMPROVE IN THE AFTERNOON
AS DRIER AIR MOVES IN.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...HALBACH
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...HALBACH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
559 PM CST SUN NOV 24 2013
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 201 PM CST SUN NOV 24 2013
MAIN SHORT TERM FORECAST CONCERN IS ON PRECIPITATION CHANCES LATER
TONIGHT...ALONG WITH HOW MUCH AND POTENTIAL FOR FREEZING DRIZZLE.
CURRENTLY AS OF 20Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED RIDGING ALONG THE WEST COAST OF NORTH AMERICA...SUBTROPICAL
STREAM TROUGH OVER ARIZONA...AND NORTHERN STREAM TROUGHING FROM
CENTRAL CANADA INTO NEW ENGLAND. WITHIN THIS TROUGHING...A FAIRLY
POTENT SHORTWAVE WAS SEEN DIVING SOUTHEAST THROUGH SASKATCHEWAN.
AHEAD OF THIS TROUGH...VAD WIND PROFILES DEPICT 30-45 KT 925MB WINDS
ACROSS THE EASTERN DAKOTAS AND MINNESOTA. THESE WINDS HAVE BEEN
ADVECTING WARMER AIR TOWARDS THE FORECAST AREA...WITH 925MB TEMPS
NOW PER RAP ANALYSIS AT -7 TO -12C...COMPARED TO -12 TO -14C AT 12Z.
AIRMASS REMAINS RELATIVELY DRY...THOUGH...WITH PRECIPITABLE WATER
VALUES JUST BELOW 0.25 INCH ACROSS THE UPPER MIDWEST. UPSTREAM IN
THE WAKE OF THE SHORTWAVE...ANOTHER ARCTIC AIR SURGE WAS BREWING
ACROSS THE NORTHWEST TERRITORIES WHERE TEMPERATURES ARE SITTING IN
THE SINGLE DIGITS AND TEENS ABOVE ZERO.
MODELS ARE IN GOOD AGREEMENT SLIDING THE POTENT SHORTWAVE OVER
SASKATCHEWAN SOUTHEAST INTO NORTHERN PORTIONS OF MN...WI AND MI
MONDAY MORNING...THEN HEADING OFF TO EASTERN ONTARIO DURING THE
AFTERNOON. AS THE SHORTWAVE APPROACHES TONIGHT...SFC/925/850MB WINDS
ALL INCREASE OVER THE FORECAST AREA...SETTING UP FOR A MUCH WARMER
NIGHT. IN ADDITION...THESE WINDS WILL ADVECT IN A TONGUE OF
RELATIVELY HIGHER MOISTURE FROM WESTERN KS AND EASTERN COLORADO...AS
WELL AS FROM UP IN SOUTHERN MANITOBA...NOTED BY PRECIPITABLE WATER
CLIMBING TO AROUND 0.5 INCH. THE HIGHEST PRECIPITABLE WATER IS
CONFINED TO NORTHEAST IOWA AND SOUTHERN WI WHICH WOULD THEREFORE BE
THE GREATEST CONCERN FOR PRECIPITATION. ALBEIT...THE GENERAL LOW
AMOUNT OF PRECIPITABLE WATER WILL LIKELY LIMIT THE AMOUNT OF
PRECIPITATION. REGARDING LIFT...280-290K ISENTROPIC SURFACES DEPICT
AN INCREASE OF NET ADIABATIC OMEGA ACROSS THE FORECAST AREA BETWEEN
06 AND 12Z...THEN SLIDES OFF TO THE SOUTHEAST. GENERAL MODEL
CONSENSUS HAS BEEN HOLDING STEADY SUGGESTING PRECIPITATION BREAKING
OUT ACROSS NORTHEAST IOWA LATE TONIGHT...THEN SPREADING INTO
SOUTHERN AND PERHAPS CENTRAL WISCONSIN MONDAY MORNING. SINCE
SATURATION OCCURS FROM THE LOW TO MID LEVELS OF THE ATMOSPHERE...THE
PRECIPITATION TYPE SHOULD BE MOSTLY SNOW...BUT CANNOT RULE OUT SOME
FREEZING DRIZZLE POSSIBLE EITHER AT THE ONSET OR ON THE NORTH SIDE
OF THE DEEPER MOISTURE. ANOTHER CONCERN IS PRECIPITATION BREAKING
OUT ALONG THE POTENT SHORTWAVES WARM FRONT. 24.12Z GFS/HIRESARW AND
24.15Z SREF ALL SUGGEST THAT AS THE FRONT RUNS INTO LOW LEVEL
STRATUS WHICH DEVELOPED LATE TONIGHT AHEAD OF IT...VERTICAL MOTION
WITH THE FRONT CAN PRODUCE LIGHT PRECIPITATION. THIS WOULD APPEAR TO
BE THE BEST CHANCE TO SEE FREEZING DRIZZLE. MUCH OF THE FORECAST
AREA WOULD HAVE A CONCERN FOR THIS DEVELOPING...INCLUDING NORTHEAST
IA AND SOUTHERN WI WHEN THE SNOW THERE DEPARTS.
GIVEN THAT THE PROBABILITY OF FREEZING DRIZZLE IS LOW AT THIS
TIME...ON THE ORDER OF 20 TO MAYBE 30 PERCENT...HAVE NOT ISSUED ANY
WINTER WEATHER ADVISORIES. FURTHER SHIFTS MAY NEED TO ISSUE
THEM...THOUGH...IF FREEZING DRIZZLE LOOKS MORE LIKELY TO OCCUR.
TEMPERATURE WISE...WE SHOULD SEE TEMPERATURES HOLD EITHER NEARLY
STEADY AND LIKELY RISE AFTER MIDNIGHT AS THE BREEZY SOUTH WINDS
BRING IN WARMER AIR AT THE SURFACE. THERE IS POTENTIAL FOR SOME
CLEARING MONDAY AFTERNOON...WHICH WITH 925MB TEMPS WARMING TO -2 TO -
4C IN THE AFTERNOON...HIGHS SHOULD CLIMB INTO THE 30S IN MOST
LOCATIONS.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 201 PM CST SUN NOV 24 2013
FOCUS OF THE LONG TERM PERIOD IS ON AN ARCTIC COOL SHOT SLATED FOR
TUESDAY INTO WEDNESDAY...AND ANY POSSIBLE PRECIPITATION THURSDAY
INTO THE WEEKEND.
MODELS DEPICT ANOTHER POTENT SHORTWAVE DROPPING OUT OF THE NORTHWEST
TERRITORIES AND DOWN INTO THE FORECAST AREA ON TUESDAY. THIS POTENT
SHORTWAVE REALLY HELPS TO BRING DOWN THE ARCTIC AIR OBSERVED UP
THERE. AT THE SAME TIME...WITH THE ARCTIC COLD FRONTAL PASSAGE
OCCURRING IN THE MORNING...LOW LEVEL MOISTURE GETS TRAPPED. THIS
MOISTURE COMBINED WITH DAYTIME HEATING WILL MANIFEST ITSELF INTO A
FAIRLY WIDESPREAD STRATUS DECK. STEEP LOW LEVEL LAPSE RATES ALONG
WITH THE STRATUS DECK BEING IN THE DENDRITIC GROWTH ZONE IS LIKELY
TO LEAD TO FLURRIES AT A MINIMUM...AND WOULD NOT BE SURPRISED IF
SOME LOW CHANCES OF PRECIPITATION WILL NEED TO BE ADDED.
WITH THE ARCTIC COLD FRONTAL PASSAGE TUESDAY MORNING...EXPECT
TEMPERATURES TO NOT RISE MUCH AND IF ANYTHING WILL LIKELY FALL
DURING THE AFTERNOON HOURS. 925MB TEMPS FALL TO -12C BY 00Z
WEDNESDAY AND TO AROUND -14C BY 12Z WEDNESDAY. THERE IS A CONTINUING
NORTHWEST BREEZE THROUGH THIS PERIOD WHICH WILL TEMPER A BIT ON HOW
COLD WE GET TUESDAY NIGHT...AND LEANED MORE TOWARDS THE MET GUIDANCE
FOR LOWS. ON THE FLIP SIDE...EXPECT COLDER WIND CHILLS BECAUSE OF
THE BREEZE. SOME MODERATION TAKES PLACE IN 925MB TEMPS ON WEDNESDAY
WITH SUN SO THAT TEMPERATURES CAN CLIMB BACK INTO THE LOW TO MID
20S.
THE UPPER FLOW FROM THANKSGIVING AND BEYOND LOOKS TO CHANGE...GOING
FROM THE NORTHWESTERLY PATTERN WE HAVE BEEN IN RECENTLY TOWARDS MORE
ZONAL. THERE ARE EVEN HINTS IN THE 24.12Z ECMWF OF THE FLOW BACKING
SOUTHWESTERLY EARLY NEXT WEEK. THIS PATTERN CHANGE WILL HELP
DISLODGE SOME OF THE COLD AIR...THUS FOLLOWED A CONSENSUS FORECAST
DEPICTING A GRADUAL MODERATING TREND FOR TEMPERATURES. REGARDING
PRECIPITATION CHANCES...DURING THE PATTERN CHANGE...THERE ARE
SHORTWAVE TROUGHS TRAVERSING ACROSS NORTHERN MN INTO UPPER MI ON
THANKSGIVING AND ON SATURDAY. RIGHT NOW BASED ON THE TRACK WOULD
SUGGEST THE BETTER CHANCES FOR PRECIPITATION WOULD STAY NORTH OF THE
FORECAST AREA. HOWEVER...THAT SATURDAY SHORTWAVE TROUGH APPEARS TO
TAKE A BIT FARTHER SOUTH TRACK COMPARED TO THE ONE ON
THANKSGIVING...THUS 20 PERCENT CHANCES OF SNOW ARE IN THE
FORECAST FOR BOTH SATURDAY AND SATURDAY NIGHT. FRIDAY AND SUNDAY
APPEAR DRY AT THIS TIME BETWEEN SHORTWAVE TROUGHS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 559 PM CST SUN NOV 24 2013
WINDY CONDITIONS TO CONTINUE OVERNIGHT WITH A PERIOD OF FREEZING
DRIZZLE POSSIBLE TOMORROW MORNING. SUSTAINED WINDS WILL REMAIN
STRONG OVERNIGHT WITH SOME LOW LEVEL WIND SHEAR EXPECTED TO
DEVELOP QUICKLY THIS EVENING. WINDS WILL INCREASE TO BETWEEN
50-60KTS AROUND 2KFT WHILE BEING AROUND 15-20KTS AT THE SURFACE.
LOW LEVEL MOISTURE WILL START TO INCREASE TOMORROW MORNING AS TWO
SYSTEMS MOVE INTO THE REGION. THE MAIN CHANCES FOR SNOW APPEAR TO
BE FURTHER TO THE SOUTH WHERE THE MOISTURE/LIFT IS DEEPER WITH
ABOUT A 2-6 HOUR PERIOD OF FREEZING DRIZZLE POSSIBLE AT THE TAF
SITES. FLIGHT CONDITIONS WILL LIKELY DROP TO MVFR/IFR AS THIS
DRIZZLE BEGINS...BUT THEN SHOULD QUICKLY IMPROVE IN THE AFTERNOON
AS DRIER AIR MOVES IN.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...HALBACH
AREA FORECAST DISCUSSION
NWS PUEBLO CO
133 AM MST MON NOV 25 2013
.UPDATE...
ISSUED AT 129 AM MST MON NOV 25 2013
ISSUED WINTER WEATHER ADVISORY FOR SOUTHERN I-25 CORRIDOR AS BAND
OF VERY HEAVY SNOW CONTINUES ALONG AND JUST WEST OF THE
INTERSTATE. HAD HOPED ONSET OF NORTH WINDS WOULD BOOST TEMPS ABOVE
FREEZING AND LIMIT ACCUMS...BUT LATEST OBS HAVE FALLEN BACK
SLIGHTLY AS HEAVIER PRECIP DRIVES TEMPS DOWNWARD. HAVE ALREADY
RECEIVED REPORTS OF 6 INCHES AROUND WALSENBURG. OTHER CHANGE TO
FORECAST WAS TO EXTEND ADVISORY UNTIL 16Z FOR THE WETS AND
SOUTHERN SANGRES AS SNOWFALL WILL BE SLIGHTLY SLOWER TO END.
UPDATE ISSUED AT 611 PM MST SUN NOV 24 2013
UPDATED SNOW GRIDS TO INCREASE AMOUNTS. BAND HAS BEEN PRODUCING A
QUICK 1 TO 4 INCHES ACROSS EL PASO AND PUEBLO COUNTIES. WITH
TRAJECTORY OF SNOW ENHANCEMENT HEADED TOWARDS THE WET
MOUNTAINS...ADDED THE LOWER ELEVATIONS OF THE WETS AND THE LOWER
ELEVATIONS OF THE SANGRES TO THE WINTER WEATHER ADVISORY. HAVE AN
SPS OUT FOR EL PASO AND PUEBLO COUNTIES FOR NOW. ITS POSSIBLE THAT
THESE AREAS MAY NEED TO BE UPGRADED TO AN ADVISORY...BUT THE VAST SPATIAL
VARIABILITY BETWEEN THE HEAVY SNOW AND WHERE THERE IS NO SNOW
ACROSS THESE ZONES MAKES THIS A LESS FAVORABLE OPTION FOR
NOW...BUT WILL CONTINUE TO MONITOR AND REASSESS AS NEEDED. -KT
UPDATE ISSUED AT 459 PM MST SUN NOV 24 2013
QUICK UPDATE TO BUMP UP POPS ACROSS EL PASO AND NORTHWEST PUEBLO
COUNTIES WHERE DEFORMATION BAND HAS SET UP. GETTING REPORTS OF MODERATE
SNOW WITHIN THIS BAND AND SUSPECT A QUICK INCH OR TWO WILL BE
POSSIBLE WITHIN THE NEXT HOUR OR TWO. BASED ON SHORT RANGE HIGH RES
MODELS...FOCUS FOR HEAVIER SNOWFALL WILL SHIFT INTO THE NORTHEAST
FACING SLOPES OF THE SOUTHEAST MOUNTAINS AND FREMONT COUNTY AS THE
EVENING PROGRESSES. HOWEVER MODELS ARE NOT RESOLVING THE CURRENT
SNOW BAND VERY WELL...SO EXPECT A HIGHLY EVOLVING FORECAST TONIGHT
AS THESE DETAILS GET RESOLVED. FOR NOW...HAVE BUMPED UP POPS INTO
THE LIKELY CATEGORY FOR EL PASO...FREMONT...AND WESTERN PUEBLO
COUNTIES THROUGH 06Z. IF BAND STALLS OVER ANY PARTICULAR
AREA...SOME LOCAL ACCUMULATIONS OF UP TO 4 INCHES WILL BE POSSIBLE
OVER THE LOWER ELEVATIONS. -KT
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 241 PM MST SUN NOV 24 2013
...SNOW WINDING DOWN ON MONDAY...
UPPER LOW IS NOW NOW MOVING EASTWARD ALONG THE CO NM BORDER. COLDER CLOUD
TOPS HAVE SHIFTED TO THE NE PORTION OF CO...WHERE SEVERAL BANDS OF
SNOW ARE ROTATING NORTHWESTWARD ALONG THE NRN I-25 CORRIDOR. THE LOW HAS
DEFINITELY TAKEN A MORE NRN TRACK AS THE NAM AND ESPECIALLY THE
ECMWF HAD FORECAST IT TO DO. HOWEVER...NOT A LOT OF MOISTURE LEFT
WITH THE SYSTEM...AND ACCUMS TONIGHT INTO MON MORNING PROBABLY WILL
NOT BE ALL THAT IMPRESSIVE. MAIN FOCUS FOR HEAVIER ACCUMS WILL BE
DUE TO N-NE WINDS INCREASING TONIGHT AS THE LOW CONTINUES TO MOVE
AWAY. LATEST RUC SHOWING H7 WINDS INCREASING TO 30-40 KTS AFTER
ABOUT 04Z TONIGHT. THIS WILL LEAD TO SOME DECENT OROGRAPHIC ACCUMS
OVER THE HIGHER ELEVATIONS OF THE ERN MT RANGES OVERNIGHT...AND
FAVORED SPOTS LIKE CUCHARA COULD SEE SOME RESPECTABLE SNOWFALL.
LATEST HI RES MODELS REALLY SHOWING THIS POTENTIAL OVER THE WETS AND
NRN SANGRES...SO WILL ADD THE WETS TO THE CURRENT SUITE OF
ADVISORIES WE HAVE OUT THROUGH 12Z MONDAY. ELSEWHERE...BEST BET OF
SNOW OVER THE PLAINS WILL BE ALONG AND WEST OF I-25...AND ESPECIALLY
SOUTH OF HIGHWAY 50. COULD SEE SOME LIGHT ACCUMS OVER THE HIGHER
TRRN BUT NOT EXPECTING ANYTHING SIGNIFICANT. INHERITED LOW POPS FOR
THE PLAINS STILL LOOK ON TARGET SO HAVE NOT MADE ANY EXTENSIVE
CHANGES THERE.
SHOULD SEE SNOW TAPER OFF FROM N TO S ESPECIALLY AFTER MID-MORNING
ON MONDAY. JUST A FEW LINGERING SHOWERS OVER THE SRN MTS AND FAR
SERN PLAINS BY MON AFTERNOON. BREEZY CONDITIONS WILL PERSIST IN THE
WAKE OF THE LOW...ESPECIALLY OVER BACA COUNTY WHICH COULD SEE SOME
GUSTS IN THE 30-40 KT RANGE FOR THE LATE MORNING TO EARLY AFTERNOON
PERIOD. TEMPS ALOFT WILL ACTUALLY BE FALLING SIGNIFICANTLY THROUGH
MONDAY MORNING...DOWN TO AROUND MINUS 7 OR 8 C AT H7...BUT WITH GOOD
MIXING IN THE LOW TO MID LEVELS...SHOULD SEE TEMPS TOP OUT HIGHER
THAN THE TEMPS THIS AFTERNOON. HAVE CUT BACK TEMPS A BIT BELOW
GUIDANCE HOWEVER...SINCE EVEN WITH GOOD ADIABATIC MIXING THE TEMPS
ALOFT WILL PROBABLY ONLY SUPPORT 40 DEGREES OR SO AT BEST BY THE
AFTERNOON. SO...IT WILL BE A RAW DAY DESPITE THE LOWERED POPS.
ROSE
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 241 PM MST SUN NOV 24 2013
MONDAY NIGHT...UPPER LOW OVER WEST TEXAS FORECAST BY MODELS TO SLIDE
SOUTHEAST...BUT SOME MOISTURE IN NORTHERLY FLOW ALOFT WILL PERSIST
THROUGH PART OF THE NIGHT. INHERITED ISOLATED POPS AT MOST OVER THE
EASTERN MOUNTAINS THROUGH MIDNIGHT...AND THAT LOOKS GOOD. SNOW
ACCUMULATIONS WILL BE WELL UNDER AN INCH. LOW TEMPERATURES WILL BE
IN THE LOWER SINGLE DIGITS ACROSS THE SAN LUIS VALLEY...WITH SNOW
COVER AND RADIATIONAL COOLING. ELSEWHERE...TEMPERATURES SHOULD DIP
INTO THE TEENS ACROSS THE PLAINS AND OTHER HIGH VALLEYS...WITH
SINGLE DIGITS ACROSS THE HIGHEST ELEVATIONS.
FOR THE REMAINDER OF THE WEEK AND INTO NEXT WEEKEND...THE WEATHER
LOOKS TO BE FAIRLY TRANQUIL...AS AN UPPER LEVEL RIDGE GETS
ESTABLISHED OVER THE GREAT BASIN AND ROCKIES. A WEAK FRONT MAY
BRIEFLY AFFECT THE EASTERN PLAIN THANKSGIVING DAY...BUT WITH NO
PRECIPITATION. A COUPLE MORE SHORTWAVES IN THE NORTHERN
STREAM...WILL BRING SOME CLOUDS...WITH THE SECOND ONE...DURING THE
WEEKEND...BRINGING A CHANCE FOR SOME HIGHER ELEVATION SNOW SHOWERS.
-TLM-
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1030 PM MST SUN NOV 24 2013
THE UPPER LOW TRACKING ACROSS NORTHERN NM WAS CONTINUING TO DRAW
MOISTURE AND SFC FLOW OUT OF THE N-NE. SNOWFALL BLOSSOMED UNDER
THIS FLOW AROUND 4 PM THIS EVE AND HAS CONTINUED THROUGHOUT THE
NIGHT...WITH THE HEAVIEST BAND INITIALLY OVER SOUTHERN EL PASO
COUNTY GRADUALLY SAGGING TO THE SOUTH. HEAVIEST HIT AREAS HAVE
BEEN THE WET MT VALLEY...EASTERN MTS...AND LOCALIZED AREAS ON THE
BACKSIDE OF THE SANGRES WHERE SNOW HAS SEEMINGLY SPILLED OVER THE
RIDGE. THE HEAVIER SNOWFALL HAS NOW DROPPED SOUTH...WHERE IFR TO
LIFR CONDITIONS ARE AFFECTING KALS AND KTAD. FURTHER NORTH...KPUB
REPORTED MVFR TO IFR CONDITIONS...AND KCOS HAS NOW CLEARED OUT OF
THE SNOW WITH VFR CONDITIONS.
THE UPPER LOW WILL CONTINUE EAST OVERNIGHT AND THROUGH
TOMORROW...AND SNOW IS EXPECTED TO DIMINISH OVERNIGHT ACROSS THE
SOUTHERN TIER BETWEEN 08Z AND 10Z. STRONG AND GUSTY NORTHERLY
WINDS WILL SETTLE IN ACROSS THE AREA ON THE BACK SIDE OF THE
DEPARTING LOW...LASTING UNTIL AROUND 15Z. MOORE
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 5 AM MST EARLY THIS MORNING FOR
COZ060-066-072-073.
WINTER STORM WARNING UNTIL 5 AM MST EARLY THIS MORNING FOR
COZ068.
WINTER WEATHER ADVISORY UNTIL 9 AM MST THIS MORNING FOR COZ074-
075-079-080-087-088.
&&
$$
UPDATE...PETERSEN
SHORT TERM...ROSE
LONG TERM...TM
AVIATION...MOORE
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1041 PM MST SUN NOV 24 2013
.UPDATE...
ISSUED AT 611 PM MST SUN NOV 24 2013
UPDATED SNOW GRIDS TO INCREASE AMOUNTS. BAND HAS BEEN PRODUCING A
QUICK 1 TO 4 INCHES ACROSS EL PASO AND PUEBLO COUNTIES. WITH
TRAJECTORY OF SNOW ENHANCEMENT HEADED TOWARDS THE WET
MOUNTAINS...ADDED THE LOWER ELEVATIONS OF THE WETS AND THE LOWER
ELEVATIONS OF THE SANGRES TO THE WINTER WEATHER ADVISORY. HAVE AN
SPS OUT FOR EL PASO AND PUEBLO COUNTIES FOR NOW. ITS POSSIBLE THAT
THESE AREAS MAY NEED TO BE UPGRADED TO AN ADVISORY...BUT THE VAST SPATIAL
VARIABILITY BETWEEN THE HEAVY SNOW AND WHERE THERE IS NO SNOW
ACROSS THESE ZONES MAKES THIS A LESS FAVORABLE OPTION FOR
NOW...BUT WILL CONTINUE TO MONITOR AND REASSESS AS NEEDED. -KT
UPDATE ISSUED AT 459 PM MST SUN NOV 24 2013
QUICK UPDATE TO BUMP UP POPS ACROSS EL PASO AND NORTHWEST PUEBLO
COUNTIES WHERE DEFORMATION BAND HAS SET UP. GETTING REPORTS OF MODERATE
SNOW WITHIN THIS BAND AND SUSPECT A QUICK INCH OR TWO WILL BE
POSSIBLE WITHIN THE NEXT HOUR OR TWO. BASED ON SHORT RANGE HIGH RES
MODELS...FOCUS FOR HEAVIER SNOWFALL WILL SHIFT INTO THE NORTHEAST
FACING SLOPES OF THE SOUTHEAST MOUNTAINS AND FREMONT COUNTY AS THE
EVENING PROGRESSES. HOWEVER MODELS ARE NOT RESOLVING THE CURRENT
SNOW BAND VERY WELL...SO EXPECT A HIGHLY EVOLVING FORECAST TONIGHT
AS THESE DETAILS GET RESOLVED. FOR NOW...HAVE BUMPED UP POPS INTO
THE LIKELY CATEGORY FOR EL PASO...FREMONT...AND WESTERN PUEBLO
COUNTIES THROUGH 06Z. IF BAND STALLS OVER ANY PARTICULAR
AREA...SOME LOCAL ACCUMULATIONS OF UP TO 4 INCHES WILL BE POSSIBLE
OVER THE LOWER ELEVATIONS. -KT
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 241 PM MST SUN NOV 24 2013
...SNOW WINDING DOWN ON MONDAY...
UPPER LOW IS NOW NOW MOVING EASTWARD ALONG THE CO NM BORDER. COLDER CLOUD
TOPS HAVE SHIFTED TO THE NE PORTION OF CO...WHERE SEVERAL BANDS OF
SNOW ARE ROTATING NORTHWESTWARD ALONG THE NRN I-25 CORRIDOR. THE LOW HAS
DEFINITELY TAKEN A MORE NRN TRACK AS THE NAM AND ESPECIALLY THE
ECMWF HAD FORECAST IT TO DO. HOWEVER...NOT A LOT OF MOISTURE LEFT
WITH THE SYSTEM...AND ACCUMS TONIGHT INTO MON MORNING PROBABLY WILL
NOT BE ALL THAT IMPRESSIVE. MAIN FOCUS FOR HEAVIER ACCUMS WILL BE
DUE TO N-NE WINDS INCREASING TONIGHT AS THE LOW CONTINUES TO MOVE
AWAY. LATEST RUC SHOWING H7 WINDS INCREASING TO 30-40 KTS AFTER
ABOUT 04Z TONIGHT. THIS WILL LEAD TO SOME DECENT OROGRAPHIC ACCUMS
OVER THE HIGHER ELEVATIONS OF THE ERN MT RANGES OVERNIGHT...AND
FAVORED SPOTS LIKE CUCHARA COULD SEE SOME RESPECTABLE SNOWFALL.
LATEST HI RES MODELS REALLY SHOWING THIS POTENTIAL OVER THE WETS AND
NRN SANGRES...SO WILL ADD THE WETS TO THE CURRENT SUITE OF
ADVISORIES WE HAVE OUT THROUGH 12Z MONDAY. ELSEWHERE...BEST BET OF
SNOW OVER THE PLAINS WILL BE ALONG AND WEST OF I-25...AND ESPECIALLY
SOUTH OF HIGHWAY 50. COULD SEE SOME LIGHT ACCUMS OVER THE HIGHER
TRRN BUT NOT EXPECTING ANYTHING SIGNIFICANT. INHERITED LOW POPS FOR
THE PLAINS STILL LOOK ON TARGET SO HAVE NOT MADE ANY EXTENSIVE
CHANGES THERE.
SHOULD SEE SNOW TAPER OFF FROM N TO S ESPECIALLY AFTER MID-MORNING
ON MONDAY. JUST A FEW LINGERING SHOWERS OVER THE SRN MTS AND FAR
SERN PLAINS BY MON AFTERNOON. BREEZY CONDITIONS WILL PERSIST IN THE
WAKE OF THE LOW...ESPECIALLY OVER BACA COUNTY WHICH COULD SEE SOME
GUSTS IN THE 30-40 KT RANGE FOR THE LATE MORNING TO EARLY AFTERNOON
PERIOD. TEMPS ALOFT WILL ACTUALLY BE FALLING SIGNIFICANTLY THROUGH
MONDAY MORNING...DOWN TO AROUND MINUS 7 OR 8 C AT H7...BUT WITH GOOD
MIXING IN THE LOW TO MID LEVELS...SHOULD SEE TEMPS TOP OUT HIGHER
THAN THE TEMPS THIS AFTERNOON. HAVE CUT BACK TEMPS A BIT BELOW
GUIDANCE HOWEVER...SINCE EVEN WITH GOOD ADIABATIC MIXING THE TEMPS
ALOFT WILL PROBABLY ONLY SUPPORT 40 DEGREES OR SO AT BEST BY THE
AFTERNOON. SO...IT WILL BE A RAW DAY DESPITE THE LOWERED POPS.
ROSE
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 241 PM MST SUN NOV 24 2013
MONDAY NIGHT...UPPER LOW OVER WEST TEXAS FORECAST BY MODELS TO SLIDE
SOUTHEAST...BUT SOME MOISTURE IN NORTHERLY FLOW ALOFT WILL PERSIST
THROUGH PART OF THE NIGHT. INHERITED ISOLATED POPS AT MOST OVER THE
EASTERN MOUNTAINS THROUGH MIDNIGHT...AND THAT LOOKS GOOD. SNOW
ACCUMULATIONS WILL BE WELL UNDER AN INCH. LOW TEMPERATURES WILL BE
IN THE LOWER SINGLE DIGITS ACROSS THE SAN LUIS VALLEY...WITH SNOW
COVER AND RADIATIONAL COOLING. ELSEWHERE...TEMPERATURES SHOULD DIP
INTO THE TEENS ACROSS THE PLAINS AND OTHER HIGH VALLEYS...WITH
SINGLE DIGITS ACROSS THE HIGHEST ELEVATIONS.
FOR THE REMAINDER OF THE WEEK AND INTO NEXT WEEKEND...THE WEATHER
LOOKS TO BE FAIRLY TRANQUIL...AS AN UPPER LEVEL RIDGE GETS
ESTABLISHED OVER THE GREAT BASIN AND ROCKIES. A WEAK FRONT MAY
BRIEFLY AFFECT THE EASTERN PLAIN THANKSGIVING DAY...BUT WITH NO
PRECIPITATION. A COUPLE MORE SHORTWAVES IN THE NORTHERN
STREAM...WILL BRING SOME CLOUDS...WITH THE SECOND ONE...DURING THE
WEEKEND...BRINGING A CHANCE FOR SOME HIGHER ELEVATION SNOW SHOWERS.
-TLM-
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1030 PM MST SUN NOV 24 2013
THE UPPER LOW TRACKING ACROSS NORTHERN NM WAS CONTINUING TO DRAW
MOISTURE AND SFC FLOW OUT OF THE N-NE. SNOWFALL BLOSSOMED UNDER
THIS FLOW AROUND 4 PM THIS EVE AND HAS CONTINUED THROUGHOUT THE
NIGHT...WITH THE HEAVIEST BAND INITIALLY OVER SOUTHERN EL PASO
COUNTY GRADUALLY SAGGING TO THE SOUTH. HEAVIEST HIT AREAS HAVE
BEEN THE WET MT VALLEY...EASTERN MTS...AND LOCALIZED AREAS ON THE
BACKSIDE OF THE SANGRES WHERE SNOW HAS SEEMINGLY SPILLED OVER THE
RIDGE. THE HEAVIER SNOWFALL HAS NOW DROPPED SOUTH...WHERE IFR TO
LIFR CONDITIONS ARE AFFECTING KALS AND KTAD. FURTHER NORTH...KPUB
REPORTED MVFR TO IFR CONDITIONS...AND KCOS HAS NOW CLEARED OUT OF
THE SNOW WITH VFR CONDITIONS.
THE UPPER LOW WILL CONTINUE EAST OVERNIGHT AND THROUGH
TOMORROW...AND SNOW IS EXPECTED TO DIMINISH OVERNIGHT ACROSS THE
SOUTHERN TIER BETWEEN 08Z AND 10Z. STRONG AND GUSTY NORTHERLY
WINDS WILL SETTLE IN ACROSS THE AREA ON THE BACK SIDE OF THE
DEPARTING LOW...LASTING UNTIL AROUND 15Z. MOORE
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 5 AM MST MONDAY FOR COZ060-066-
072>075-079-080.
WINTER STORM WARNING UNTIL 5 AM MST MONDAY FOR COZ068.
&&
$$
UPDATE...KT
SHORT TERM...ROSE
LONG TERM...TM
AVIATION...MOORE
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
323 AM CST MON NOV 25 2013
.DISCUSSION...
323 AM CST
WITH NOVEMBER LOOKING TO FINISH WITH CONTINUED BELOW NORMAL
TEMPERATURES DURING ITS FINAL WEEK WITH LITTLE IN THE WAY OF SHARP
THERMAL CHANGES...THE PRIMARY FOCUS OF THE FORECAST WAS ON THE LIGHT
SNOW EVENT TODAY AND THEN THE LAKE EFFECT SNOW POTENTIAL INTO
NORTHWEST INDIANA TUESDAY NIGHT AND WEDNESDAY.
SOMEWHAT SPLIT UPPER FLOW IS IN PLACE ACROSS THE CENTRAL U.S. THIS
MONDAY WITH A QUICKLY-MOVING TROUGH ACROSS ONTARIO DIVING INTO THE
GREAT LAKES BY AFTERNOON...AND A CLOSED LOW ACROSS THE TEXAS
PANHANDLE BRINGING RARE NOVEMBER WINTER WEATHER HEADLINES TO THE
SOUTHERN PLAINS. OUR FORECAST AREA BASICALLY FALLS BETWEEN THESE TWO
SYSTEMS TODAY AND AS A RESULT THERE IS A VOID OF ANY OVERLY STRONG
FORCING OVERHEAD. ISENTROPIC ASCENT AND SATURATION WITHIN THE WSW
FLOW ALOFT THIS MORNING LOOKS TO BE THE PRIMARY CONTRIBUTOR TO
PRECIPITATION GENERATION...ALTHOUGH DRY LOW-LEVELS MAY KEEP IT
FLURRIES THROUGH MID TO LATE MORNING OVER CHICAGO. AN AXIS OF
FRONTOGENESIS CENTERED TO THE NORTHWEST OF THE AREA FROM EASTERN IA
INTO SOUTHERN WI THROUGH ~10 AM ON THE RAP AND LOCAL ARW MAY RESULT
IN BETTER SNOWFALL CLIPPING THE ROCKFORD AREA THIS MORNING...AND
CONCEIVABLY COULD SEE AN INCH BECAUSE OF THAT BUT THAT WOULD SEEM
THE MAXIMUM. AS THE SUBTLE FORCING AND MID-LEVEL SATURATION EVOLVES
EAST INTO THE AFTERNOON...PERIODS OF LIGHT SNOW WILL LIKELY RESULT
IN ONE HALF INCH OR LESS FOR MOST COMMUNITIES...AND NAMELY NORTH OF
I-80. WHILE NOT THE MOST IDEAL SYNOPTIC SETUP FOR FREEZING
DRIZZLE...THERE ARE SOME SIGNS ON GUIDANCE THAT AS ICE INTRODUCTION
IS LOST DURING THE MID TO LATE AFTERNOON THAT THERE MAY BE A BRIEF
WINDOW FOR THIS. ASCENT LOOKS WEAK AND CLOUD BASES LOOK HIGH FOR
THAT TO OCCUR THOUGH...SO CONTINUE TO NOT MENTION IN FORECAST.
THE AMOUNT OF CLOUD COVER TODAY WILL ONLY ALLOW TEMPERATURES TO RISE
BY ADVECTION...AND THAT WILL BE MEAGER AT THE SURFACE. SO MAINTAIN
HIGHS MAINLY IN THE LOWER 30S...WHICH WOULD RESULT IN THE THIRD
STRAIGHT DAY OF DOUBLE DIGIT DEPARTURES BELOW NORMAL.
A SECOND MORE ROBUST NORTHERN STREAM WAVE...THAT ACTUALLY LOOKS TO
BE A CLOSED SUB 520DM H5 LOW...WILL DROP INTO THE GREAT LAKES ON
TUESDAY. A FAIRLY DEEP PV ANOMALY IS SEEN WITH THIS ALONG WITH H5
TEMPS DOWN TO NEAR -30C...WHICH COME BARRELING INTO THE FORECAST
AREA BY LATE AFTERNOON INTO THE EVE TUESDAY ON THE GUIDANCE SUITE.
AN ASSOCIATED SURFACE COLD FRONT LOOKS TO STEEPEN LAPSE RATES AND
COULD SUPPORT SOME SNOW SHOWERS. CERTAINLY SOME FLURRIES LOOK TO BE
PRESENT INTO TUESDAY NIGHT. LOWS THAT NIGHT LOOK TO RETURN TO THE
MID AND POSSIBLY EVEN LOWER TEENS IN OUTLYING LOCATIONS.
MORE OF A CONCERN IS TURNING TO A POTENTIAL PLOWABLE SNOW FROM LAKE
EFFECT GENERATION INTO NORTHWEST INDIANA TUESDAY NIGHT INTO THE
BUSIEST TRAVEL DAY OF THE YEAR ON WEDNESDAY. THERE REMAINS MODEL
DIFFERENCES ON HOW QUICKLY THE AFOREMENTIONED SOUTHERN PLAINS UPPER
LOW AND THIS GREAT LAKES LOW PHASE. BUT OVERALL THE FLOW ACROSS LAKE
MI SHOULD BECOME STIFF AND NORTHERLY BY LATER TUESDAY NIGHT. THERE
ARE EVEN SIGNS ON SOME HIGH RESOLUTION MODELS...INCLUDING OUR LOCAL
ARW...OF MESO-LOW DEVELOPMENT TRANSLATING SOUTH ACROSS THE LAKE ON
TUESDAY NIGHT. CONFIDENCE ON SUCH A FEATURE IS LOW AT THIS
POINT...AS IS WHETHER THERE WILL EXIST A FOCUSED BAND OR JUST
WIDESPREAD SHOWERS OFF THE LAKE. BUT CONFIDENCE IS HIGH THERE WILL
BE AT LEAST SNOW SHOWERS INTO NORTHWEST INDIANA GIVE THE FORECAST
TRAJECTORIES...STEEP LOW-LEVEL LAPSE RATES...LAKE-INDUCED CAPE OF
AROUND 500 J/KG...AND EQUILIBRIUM LEVELS FORECAST AROUND 9000 FT.
THESE INDICES ACTUALLY INDICATE SOMEWHERE COULD GET A ROBUST SNOW
EVENT WITH HEAVY RATES WHICH WOULD IMPACT WEDNESDAY TRAVEL. IN
ADDITION...USING THE CIPS ANALOGS INDICATES A FAIRLY STRONG
CORRELATED EVENT FOR 850MB TEMPERATURES AND LOW-LEVEL WIND FLOW ON
11/21/08 AND THAT PRODUCED OVER 8 INCHES JUST EAST OF THE AREA. AT
THIS TIME HAVE CONTINUED THE TREND OF PREVIOUS SHIFT IN INCREASING
POPS ACROSS PORTER AND EASTERN LAKE COUNTIES.
BEYOND THERE WAS LITTLE CHANGE TO THE FORECAST AS THE HOLIDAY ITSELF
LOOKS QUIET ACROSS THE AREA WITH GRADUALLY BUILDING HEIGHTS AND
SURFACE HIGH PRESSURE. A QUASI-ZONAL PATTERN IS FAVORED ON LONG
RANGE DETERMINISTIC MODELS AND ENSEMBLES...WHICH WOULD FAVOR A
GRADUAL MODERATION TO NEAR NORMAL FOR THE FIRST DAY OF
METEOROLOGICAL WINTER ON SUNDAY.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 09Z...
* GUSTY SOUTHWEST WINDS TODAY.
* PERIODS OF LIGHT SNOW LIKELY AFTER 17 UTC THROUGH MID
AFTERNOON...PERIODS OF MVFR TO IFR VIS POSSIBLE.
KJB
//DISCUSSION...UPDATED 06Z...
THE MAIN FORECAST CONCERNS THIS MORNING REVOLVE AROUND THE LIGHT
SNOW EXPECTED ACROSS THE TERMINALS TODAY...ALONG WITH THE STRONG
SOUTHWESTERLY WINDS.
A STRONG PRESSURE GRADIENT IS SETTING UP ACROSS THE AREA EARLY THIS
MORNING IN ASSOCIATION WITH LOW PRESSURE ACROSS SOUTHERN ONTARIO AND
HIGH PRESSURE ACROSS THE SOUTHEASTERN CONUS. THIS WILL SUPPORT SOME
GUSTY WINDS TODAY. IN FACT...WINDS ARE ALREADY BEGINNING TO GUST UP
AROUND 20 KT AT ORD EARLY THIS MORNING. OVERALL EXPECTED
SOUTHWESTERLY WINDS AROUND 15 TO 17 KT WITH GUSTS UP TO 25 TO 28 KT
AFTER DAYBREAK TODAY.
THE OTHER CONCERN IS THAT FOR LIGHT SNOW. THESE STRONG SOUTHWEST
WINDS ARE EXPECTED TO TRANSPORT JUST ENOUGH MOISTURE ACROSS THE AREA
TO LEAD TO SOME LIGHT SNOW AS AN UPPER LEVEL DISTURBANCE TRACKS
ACROSS SOUTHERN WISCONSIN TODAY. OVERALL...THIS WILL NOT BE A BIG
SYSTEM...BUT LIGHT SNOW WILL LIKELY ONSET BY EARLY TO MID MORNING AR
KRFD AND BY MID MORNING ACROSS THE EASTERN TAF SITES. ONCE IT BEGINS
THERE WILL BE ABOUT A 4 TO 6 HOUR WINDOW FOR SOME LIGHT SNOW.
VISIBILITIES IN THE SNOW COULD DROP DOWN AROUND 2 MILES FOR A PERIOD
AND SOME LIGHT ACCUMULATIONS AROUND A HALF INCH ARE POSSIBLE. THE
SNOW CHANCES WILL END QUICKLY BY MID TO LATE AFTERNOON AS DRYER AIR
FILTERS IN ACROSS THE AREA. I HAVE OPTED TO REMOVE THE MENTION OF
-FZDZ AS IT APPEARS THAT ALTHOUGH THE MOISTURE WILL BE VOID IN THE
FAVORABLE AREAS FOR SNOW GROWTH...IT ALSO APPEARS THAT CIGS WILL BE
TOO HIGH TO SUPPORT ANY PRECIP ONCE THE SNOW ENDS.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 09Z...
* HIGH CONFIDENCE IN WINDS.
* MEDIUM-HIGH CONFIDENCE IN PERIODS OF LIGHT SNOW WITH MVFR TO IFR VIS.
* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
KJB
//OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z...
TUESDAY...FLURRIES WITH MVFR CIGS LIFTING TO VFR.
WEDNESDAY...LAKE EFFECT MVFR CIGS PSBL.
THURSDAY AND FRIDAY...VFR.
SATURDAY...MVFR CIGS PSBL OVERNIGHT.
JEE
&&
.MARINE...
206 AM CST
A VERY ACTIVE WEATHER PATTERN WILL CONTINUE ACROSS THE GREAT LAKES
THROUGH MID WEEK. THE CURRENT GALE EVENT IS WELL UNDERWAY WITH
SEVERAL REPORTS OF 40+ KT WINDS...ESPECIALLY ACROSS THE NORTHERN
HALF OF THE LAKE. THESE GALES WILL CONTINUE THROUGH AT LEAST THE MID
AFTERNOON HOURS TODAY AS A AN AREA OF LOW PRESSURE TRACKS EASTWARD
ACROSS SOUTHERN ONTARIO. THE WINDS WILL GRADUALLY ABATE INTO THIS
EVENING. THE CURRENT GALE HEADLINE MAY BE ALOUD TO EXPIRE A FEW
HOURS EARLIER THAN THE CURRENT 9 PM DEADLINE. HOWEVER...AT THIS
POINT I WILL LEAVE THE HEADLINE TIMING ALONE.
THE NEXT ISSUE WILL BE LATER TUESDAY THROUGH MUCH OF WEDNESDAY. A
STRONG STORM SYSTEM IS EXPECTED TO MOVE UP THE EAST COAST DURING
THIS TIME...AND AS HIGH PRESSURE BUILDS IN ACROSS THE MISSOURI
VALLEY CONDITIONS WILL BECOME FAVORABLE FOR A PERIOD OF NORTHERLY
GALES UP TO 35 TO 40 KT. THIS LOOKS TO BE THE MOST PRONOUNCED ACROSS
SOUTHERN LAKE MICHIGAN...AND ANY LAKE EFFECT BANDS OF SNOW THAT
DEVELOP DURING THIS TIME COULD LEAD ALSO EVEN LEAD TO SOME LOCALLY
HIGH WINDS IN EXCESS OF 40 KT. IT APPEARS TO BE A GOOD BET THAT A
GALE HEADLINE WILL BE NEEDED DURING THIS TIME. I THREW AROUND THE
IDEA OF HOSTING A GALE WATCH FOR THIS PERIOD...BUT DUE TO THE FACT
IT IS STILL FAR ENOUGH OUT...I HAVE DECIDED TO LET THE CURRENT
GALE HEADLINES END PRIOR TO THE ISSUANCE OF A NEW HEADLINE.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 PM MONDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 9 PM MONDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1024 PM MST SUN NOV 24 2013
.UPDATE...
ISSUED AT 952 PM MST SUN NOV 24 2013
STRATUS ERODING FROM THE WEST DESPITE NO CHANGE TO WIND DIRECTION.
SO EARLIER REASONING PER WHAT WAS THOUGHT CONSISTENT GUIDANCE WITH
REALITY IS NOT PANNING OUT. LOVE THIS GUIDANCE.
UPDATE ISSUED AT 734 PM MST SUN NOV 24 2013
JUST COMPLETED AN UPDATE. MODEL OUTPUT STILL PLAYING CATCHUP. FINALLY
LOOKS LIKE TONIGHT WILL HAVE STRATUS FOR MOST IF NOT ENTIRE NIGHT
ESPECIALLY EAST OF THE COLORADO BORDER. THE RUC AND GFS HAVE CAUGHT
THIS IDEA VERY WELL. COMBINED THAT WITH THE HIGHER DEWPOINTS COMING
IN WILL MAKE FOR MUCH WARMER MINS THAN CURRENTLY DEPICTED. NWP IS
WOEFULLY TOO COOL. NEW MINS BASED ON THE RUC AND ARE WARMER. ALSO
BASED ON THE RUC...INCREASED THE SKY COVER.
PER AREA 00Z SOUNDINGS AND THE RUC/NAM/GFS FORECAST SOUNDINGS DECIDED
TO ADD PATCHY FREEZING FOG AND DRIZZLE. MADE IT FOR THE ENTIRE NIGHT
BUT LOOKS LIKE THE BEST CHANCE FOR THIS LOOKS TO BE AFTER 06Z WHEN
THE WARM LAYER ALOFT BECOMES MORE ESTABLISHED. CONTINUED THE FZDZ
AND FZFG THROUGH MID MORNING IN THE EAST. ADJUSTED WIND FIELD BASED
ON LATEST RUC AND ADJUSTED DEWPOINTS UP PER LATEST GFS.
UPDATE ISSUED AT 441 PM MST SUN NOV 24 2013
UPDATED FORECAST DUE TO EXPIRED WIND ADVISORY. ALSO PER DIMINISHED
RADAR RETURNS REMOVED POPS FROM THE EASTERN PORTION OF THE FORECAST
AREA. ALSO ADJUSTED SKY COVER PER RECENT TRENDS.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 104 PM MST SUN NOV 24 2013
WATER VAPOR IMAGERY/RUC ANALYSIS INDICATED LARGE CLOSED H5 TROUGH
NEARING THE FOUR CORNERS AREA. AT THE SFC...STRONG PRESSURE
GRADIENT WAS IN PLACE ACROSS THE CWA WITH LOW DEEPENING OVER
COLORADO AND STRONG SFC RIDGE OVER EASTERN KS AND MO. NARROW AREA
OF STRONG WIND GUSTS IN EXCESS OF 40KTS...BETWEEN ITR AND GLD WAS
SLOWLY DIMINISHING.
WINDS SHOULD CONTINUE TO DECREASE AND FALL BELOW ADVISORY LEVELS
BEFORE SUNSET AS SFC COOLING ALLOWS BOUNDARY LAYER TO DECOUPLE. A
FEW LINGERING SNOW SHOWERS...WHICH LOOK LIKE THEY ARE BEING DRIVEN
BY ELEVATED CI WILL MOVE OUT OF THE AREA BY EARLY EVENING AS
POCKET OF DRY AIR SETTLES OVER THE AREA. UPPER LOW WILL NEAR THE
AREA TONIGHT AND WITH WEAK LIFT AND LOW STABILITY COULD SEE A
SHOWER OR TWO REDEVELOP AS IT PASSES. PROBABILITIES FROM ENSEMBLES
ARE VERY LOW AND GIVEN MUCH DRIER AIR MOVING INTO THE
AREA...CONFIDENCE NOT HIGH ENOUGH TO INCLUDE ATTM. WINDS WILL
DECREASE AND BECOME LIGHT TONIGHT PRIOR TO FRONTAL PASSAGE THAT
WILL BRING A PERIOD OF GUSTY NORTHERLY WINDS. WINDS ARE NOT
EXPECTED TO BE AS STRONG AS TODAY THOUGH. WITH A PERIOD OF LIGHT
WINDS AND SOME POTENTIAL THINNING OF THE HIGH CLOUDS HAVE LOWERED
MIN TEMPS SEVERAL DEGREES...ESPECIALLY ACROSS SOUTHERN CWA.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 140 PM MST SUN NOV 24 2013
THE LARGE UPPER LOW OVER THE SOUTHWESTERN STATES WILL FINALLY
MOVE AWAY FROM THE FORECAST AREA BY THE START OF THE EXTENDED
PERIOD. NUMERICAL GUIDANCE INDICATES A FAST NORTHWEST FLOW ALOFT
WILL SET UP OVER THE N-C PLAINS STATES IN THE TUE-WED TIME FRAME...
GRADUALLY TRANSITIONING TO A BROAD RIDGE THU-FRI...AND FINALLY TO
A WSW FLOW SAT-SUN.
SEVERAL FAST-MOVING SHORT WAVE TROUGHS WILL MOVE THROUGH THE
NORTHWEST FLOW EARLY IN THE PERIOD...IMPACTING MAINLY THE NORTHERN
PLAINS AND GREAT LAKES. THE FORECAST AREA WILL EXPERIENCE SEVERAL
COLD FRONTAL PASSAGES ASSOCIATED WITH THESE UPPER TROUGHS...BUT
NO PRECIPITATION AND LITTLE IN THE WAY OF CLOUDS IS ANTICIPATED.
THE FIRST COLD FRONT WILL MOVE THROUGH THE AREA MONDAY WHICH WILL
BRING DOWN A FAIRLY COLD CANADIAN AIR MASS TUESDAY WHICH MOVES OUT
WEDNESDAY. AFTERNOON TEMPERATURES WILL BE 8-12 DEGREES BELOW
NORMAL AS A RESULT TUE-WED WITH HIGHS 35-45F. PREFERRED AN SREF
SOLUTION FOR TEMPS DURING THIS PERIOD. A SECOND WEAKER COLD FRONT
WILL BRUSH THE AREA EARLY THURSDAY WITH MINIMAL IMPACT.
AS THE UPPER FLOW TRANSITIONS TO A BROAD RIDGE LATER IN THE
WEEK...HIGH TEMPERATURES WILL RETURN TO NORMAL WITH MID 40S-
LOWER 50S FORECAST FOR THU-SUN.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1021 PM MST SUN NOV 24 2013
STRATUS IS ERODING FROM THE WEST AND HAS MOVED EAST OF BOTH TAF
SITES. SO EXPECT TREND TO CONTINUE AND VFR CONDITIONS THROUGH THE
PERIOD. FRONT WILL MOVE THROUGH TOMORROW DURING THE MIDDLE OF THE
DAY AND EXPECT WINDS TO BECOME GUSTY UNTIL LATE IN THE AFTERNOON.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...BULLER
SHORT TERM...JRM
LONG TERM...DLF
AVIATION...BULLER
AREA FORECAST DISCUSSION
NWS GOODLAND KS
955 PM MST SUN NOV 24 2013
.UPDATE...
ISSUED AT 952 PM MST SUN NOV 24 2013
STRATUS ERODING FROM THE WEST DESPITE NO CHANGE TO WIND DIRECTION.
SO EARLIER REASONING PER WHAT WAS THOUGHT CONSISTENT GUIDANCE WITH
REALITY IS NOT PANNING OUT. LOVE THIS GUIDANCE.
UPDATE ISSUED AT 734 PM MST SUN NOV 24 2013
JUST COMPLETED AN UPDATE. MODEL OUTPUT STILL PLAYING CATCHUP. FINALLY
LOOKS LIKE TONIGHT WILL HAVE STRATUS FOR MOST IF NOT ENTIRE NIGHT
ESPECIALLY EAST OF THE COLORADO BORDER. THE RUC AND GFS HAVE CAUGHT
THIS IDEA VERY WELL. COMBINED THAT WITH THE HIGHER DEWPOINTS COMING
IN WILL MAKE FOR MUCH WARMER MINS THAN CURRENTLY DEPICTED. NWP IS
WOEFULLY TOO COOL. NEW MINS BASED ON THE RUC AND ARE WARMER. ALSO
BASED ON THE RUC...INCREASED THE SKY COVER.
PER AREA 00Z SOUNDINGS AND THE RUC/NAM/GFS FORECAST SOUNDINGS DECIDED
TO ADD PATCHY FREEZING FOG AND DRIZZLE. MADE IT FOR THE ENTIRE NIGHT
BUT LOOKS LIKE THE BEST CHANCE FOR THIS LOOKS TO BE AFTER 06Z WHEN
THE WARM LAYER ALOFT BECOMES MORE ESTABLISHED. CONTINUED THE FZDZ
AND FZFG THROUGH MID MORNING IN THE EAST. ADJUSTED WIND FIELD BASED
ON LATEST RUC AND ADJUSTED DEWPOINTS UP PER LATEST GFS.
UPDATE ISSUED AT 441 PM MST SUN NOV 24 2013
UPDATED FORECAST DUE TO EXPIRED WIND ADVISORY. ALSO PER DIMINISHED
RADAR RETURNS REMOVED POPS FROM THE EASTERN PORTION OF THE FORECAST
AREA. ALSO ADJUSTED SKY COVER PER RECENT TRENDS.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 104 PM MST SUN NOV 24 2013
WATER VAPOR IMAGERY/RUC ANALYSIS INDICATED LARGE CLOSED H5 TROUGH
NEARING THE FOUR CORNERS AREA. AT THE SFC...STRONG PRESSURE
GRADIENT WAS IN PLACE ACROSS THE CWA WITH LOW DEEPENING OVER
COLORADO AND STRONG SFC RIDGE OVER EASTERN KS AND MO. NARROW AREA
OF STRONG WIND GUSTS IN EXCESS OF 40KTS...BETWEEN ITR AND GLD WAS
SLOWLY DIMINISHING.
WINDS SHOULD CONTINUE TO DECREASE AND FALL BELOW ADVISORY LEVELS
BEFORE SUNSET AS SFC COOLING ALLOWS BOUNDARY LAYER TO DECOUPLE. A
FEW LINGERING SNOW SHOWERS...WHICH LOOK LIKE THEY ARE BEING DRIVEN
BY ELEVATED CI WILL MOVE OUT OF THE AREA BY EARLY EVENING AS
POCKET OF DRY AIR SETTLES OVER THE AREA. UPPER LOW WILL NEAR THE
AREA TONIGHT AND WITH WEAK LIFT AND LOW STABILITY COULD SEE A
SHOWER OR TWO REDEVELOP AS IT PASSES. PROBABILITIES FROM ENSEMBLES
ARE VERY LOW AND GIVEN MUCH DRIER AIR MOVING INTO THE
AREA...CONFIDENCE NOT HIGH ENOUGH TO INCLUDE ATTM. WINDS WILL
DECREASE AND BECOME LIGHT TONIGHT PRIOR TO FRONTAL PASSAGE THAT
WILL BRING A PERIOD OF GUSTY NORTHERLY WINDS. WINDS ARE NOT
EXPECTED TO BE AS STRONG AS TODAY THOUGH. WITH A PERIOD OF LIGHT
WINDS AND SOME POTENTIAL THINNING OF THE HIGH CLOUDS HAVE LOWERED
MIN TEMPS SEVERAL DEGREES...ESPECIALLY ACROSS SOUTHERN CWA.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 140 PM MST SUN NOV 24 2013
THE LARGE UPPER LOW OVER THE SOUTHWESTERN STATES WILL FINALLY
MOVE AWAY FROM THE FORECAST AREA BY THE START OF THE EXTENDED
PERIOD. NUMERICAL GUIDANCE INDICATES A FAST NORTHWEST FLOW ALOFT
WILL SET UP OVER THE N-C PLAINS STATES IN THE TUE-WED TIME FRAME...
GRADUALLY TRANSITIONING TO A BROAD RIDGE THU-FRI...AND FINALLY TO
A WSW FLOW SAT-SUN.
SEVERAL FAST-MOVING SHORT WAVE TROUGHS WILL MOVE THROUGH THE
NORTHWEST FLOW EARLY IN THE PERIOD...IMPACTING MAINLY THE NORTHERN
PLAINS AND GREAT LAKES. THE FORECAST AREA WILL EXPERIENCE SEVERAL
COLD FRONTAL PASSAGES ASSOCIATED WITH THESE UPPER TROUGHS...BUT
NO PRECIPITATION AND LITTLE IN THE WAY OF CLOUDS IS ANTICIPATED.
THE FIRST COLD FRONT WILL MOVE THROUGH THE AREA MONDAY WHICH WILL
BRING DOWN A FAIRLY COLD CANADIAN AIR MASS TUESDAY WHICH MOVES OUT
WEDNESDAY. AFTERNOON TEMPERATURES WILL BE 8-12 DEGREES BELOW
NORMAL AS A RESULT TUE-WED WITH HIGHS 35-45F. PREFERRED AN SREF
SOLUTION FOR TEMPS DURING THIS PERIOD. A SECOND WEAKER COLD FRONT
WILL BRUSH THE AREA EARLY THURSDAY WITH MINIMAL IMPACT.
AS THE UPPER FLOW TRANSITIONS TO A BROAD RIDGE LATER IN THE
WEEK...HIGH TEMPERATURES WILL RETURN TO NORMAL WITH MID 40S-
LOWER 50S FORECAST FOR THU-SUN.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 441 PM MST SUN NOV 24 2013
MODEL PROBLEMS RESOLVING THE SNOW FIELD/BOUNDARY LAYER MOISTURE
MAKE THIS A LITTLE TRICKY TAF FORECAST. CURRENTLY AT KGLD WE ARE
HAVING MVFR CEILINGS AND LOOKING UPSTREAM THESE COULD CONTINUE FOR
A WHILE. CURRENT CONDITIONS ARE BETWEEN THE MORE PESSIMISTIC NAM
AND THE MAV WHICH IS SHOWING NOTHING. RUC IS RATHER AGGRESSIVE IN
RETURNING BOUNDARY LAYER MOISTURE THIS EVENING. NAM AND RUC HAVE
BEEN THE MOST AGGRESSIVE AND WRONG MODELS THE LAST FEW DAYS WITH
THE GFS BETTER BUT ALSO OVERDOING IT SOME.
SO FOR KGLD WILL GO WITH A PERSISTENCE FORECAST THROUGH THE
EVENING WITH THE MVFR CONDITIONS AND WATCH THE TRENDS. WILL KEEP
VFR AT KMCK FOR NOW THROUGH THE PERIOD. IF MORE MOIST MODELS ARE
RIGHT WILL NEED MORE STRATUS AND MAYBE SOME FOG. SOUTH WINDS WILL
LOSE THEIR GUSTINESS IN THE NEXT HOUR OR TWO. THEN WILL BE LIGHT
AND VARIABLE UNTIL A PREFRONTAL TROUGH/COLD FRONT MOVE THROUGH
LATER TONIGHT INTO TOMORROW WHICH WILL MAKE FOR STRONG AND GUSTY
WINDS DURING THE DAY.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...BULLER
SHORT TERM...JRM
LONG TERM...DLF
AVIATION...BULLER
AREA FORECAST DISCUSSION
NWS GAYLORD MI
450 AM EST MON NOV 25 2013
.SYNOPSIS...
ISSUED AT 449 AM EST MON NOV 25 2013
WINTRY CONDITIONS WILL BE PREVALENT ACROSS NORTHERN MICHIGAN THROUGH
THE THANKSGIVING HOLIDAY WEEK...WITH SEVERAL WEAKER WEATHER SYSTEMS
DELIVERING REPEATED SHOTS OF BOTH SYSTEM AND LAKE EFFECT SNOW. THE
FIRST WILL ARRIVE THIS MORNING...AS LOW PRESSURE TRACKS NEAR JAMES
BAY...BRINGING A ROUND OF SNOW TO MUCH OF NORTHWEST LOWER AND
EASTERN UPPER. A COLD FRONT WILL GRADUALLY WORK THROUGH THE REGION
LATER TUESDAY...BRINGING RENEWED COLD CONDITIONS ALONG WITH MORE
LAKE EFFECT SNOW. THAT GENERAL TREND WILL CONTINUE INTO THANKSGIVING
DAY...BEFORE QUIET WEATHER MAKES A RETURN TOWARD NEXT WEEKEND.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 449 AM EST MON NOV 25 2013
WELL...THAT WAS A NICE 12-ISH HOUR RESPITE FROM THE ACTIVE WEATHER.
NOW IT`S GAME ON ONCE AGAIN...WITH THE MAIN FORECAST ISSUES BEING OF
THE LAKE EFFECT/ENHANCEMENT VARIETY...ALONG WITH WIND ISSUES THROUGH
THE DAY TODAY. EARLY MORNING ANALYSIS PLACES VERY WEAK SHORTWAVE
RIDGE AXIS JUST TO THE EAST OF NORTHERN MICHIGAN...WITH DEEP AND
QUITE STRONG SOUTHWESTERLY FLOW WELL RAMPED UP ACROSS THE NORTHERN
LAKES IN ADVANCE OF ANOTHER STRONG UPPER WAVE QUICKLY AMPLIFYING
THROUGH SOUTHERN MANITOBA. INITIAL PUSH OF THAT WARM ADVECTION
EARLIER LED TO A BRIEF AXIS OF LIGHT SNOW MARCHING THROUGH
NORTHERN/EASTERN AREAS...WITH SECONDARY SURGE OF MUCH DEEPER AND
STRONGER ASCENT GOING INTO GRADUAL TOP-DOWN SATURATION OFF TO OUR
WEST AT THE MOMENT...AS EVIDENCED BY CEILINGS FALLING 5-8KFT OVER
THE PAST FEW HOURS. MEANWHILE...QUITE THE WINDY CONDITIONS HAVE
SHOWN UP RECENTLY AS CORE OF RATHER IMPRESSIVE 45-55 KNOT FLOW IS
ROLLING OVERHEAD...COMBINING WITH A REMNANT UNSTABLE AIRMASS ACROSS
THE LAKES TO PRODUCE SOME RATHER BEEFY WIND GUSTS PUSHING 50 MPH
ALONG THE LAKE MICHIGAN SHORE.
THE ABOVE MENTIONED WARM ADVECTION WILL BE IMPORTANT FOR OUR AREA
THIS MORNING...AS THE ADDED MOISTURE (FROM AN INITIALLY QUITE DRY
AIRMASS) GIVES A BIG BOOST OVER LAKE MICHIGAN. ALREADY SEEING THE
FIRST HINTS OF THIS RIGHT NOW...BUT THE THOUGHT IS THAT DEEPER
MOISTURE OVERRIDING THE LAKE WILL GO INTO THE RAPID PRODUCTION OF A
SOUTHWEST FLOW LAKE BAND THE NEXT FEW HOURS...WHICH WILL ULTIMATELY
GET PUNTED ONSHORE AS THE SHARP UPPER WAVE OVER MANITOBA WORKS
TOWARD OUR AREA. THESE TYPES OF SETUPS ALWAYS HAVE TROUBLE WRITTEN
ALL OVER THEM FROM AN IMPACT STANDPOINT...AS THERE SHOULD BE A
COUPLE HOUR WINDOW FOR SOME HEAVY SNOW TO FALL UP AND DOWN THE LAKE
MICHIGAN SHORELINE COUNTIES...AND PROBABLY EVEN FARTHER INLAND INTO
THE HIGHER TERRAIN WHERE UPSLOPE TYPICALLY WORKS ITS MAGIC IN SUCH A
SETUP. GIVEN WARMING THERMAL PROFILES...SNOW TO LIQUID RATIOS SHOULD
BE RATHER LOW...AS EVIDENCED BY A QUITE DEEP ISOTHERMAL LAYER AROUND
-6C PER FORECAST RAOBS...MAKING FOR MORE OF A GREASY/SLIPPERY SNOW.
THROW IN SOME QUITE GUSTY WINDS AND THE STAGE IS PROBABLY SET FOR A
PERIOD OF SLOPPY TRAVEL/LOW VSBYS ACROSS PRIMARILY NORTHWEST
LOWER...WITH A QUICK 2-3" OF SNOW EXPECTED TO FALL. LOCAL 4/12KM APX
WRF AND RECENT HRRR RUNS ARE EVEN MORE IMPRESSIVE...PAINTING AN AXIS
OF 0.4" OF LIQUID UP TOWARD CHARLEVOIX/EMMET/CHEBOYGAN/OTSEGO/ANTRIM
COUNTIES...WITH A SECONDARY MAXIMUM NEAR CADILLAC. GIVEN THE
EXPECTED LOWER RATIOS...SHOULDN`T SEE ACCUMULATION GET OUT OF
HAND...EVEN IF THE HIGHER QPF FORECASTS VERIFY. NOT SURE THIS WILL
BE WORTHY OF A WINTER WEATHER HEADLINE - PROBABLY MORE LIKE AN
SPS...ESPECIALLY CONSIDERING THE WORST CONDITIONS SHOULD OCCUR JUST
AFTER THE MORNING COMMUTE (MAINLY 9AM-1PM).
WINDS WILL SUBSIDE HEADING INTO THE AFTERNOON AS THE CORE OF
STRONGEST 950-900MB FLOW EXITS EAST...ALL WHILE DEEPER MOISTURE ALSO
STRIPS OUT. THAT LEAVES US IN MORE OF A LIGHT SNOW SHOWERS/SNIZZLE
REGIME FOR MUCH OF THE AFTERNOON AS SOUTHWEST FLOW CONTINUES BUT
WHILE CLOUD TOP TEMPS HOVER ONLY AROUND -8C. PROBABLY NOT LOOKING AT
MUCH ADDITIONAL ACCUMULATION FOR MOST AREAS THROUGH LATE AFTERNOON.
HOWEVER...MORE ISSUES SHOW UP BY EARLY EVENING WITH PERSISTENT HINTS
OF A STRONGER FRONTAL SNOW BAND BEING BROUGHT ASHORE INTO EASTERN
UPPER AS LOW PRESSURE NEARS THE SOUTHERN TIP OF JAMES BAY AND SWINGS
A COLD FRONT THROUGH THE EASTERN U.P. THAT FEATURE WILL IN ALL
LIKELIHOOD BECOME ABSORBED INTO THE LAKE AGGREGATE TROUGH OVER
EASTERN LAKE SUPERIOR...WITH PERHAPS EVEN A WEAK CIRCULATION CENTER
DEVELOPING IN RESPONSE TO YET ANOTHER STRONG UPPER WAVE ENTERING THE
ARROWHEAD OF MINNESOTA. THAT SETUP COULD LEAD TO ALL KINDS OF
MESOSCALE GARBAGE...BUT THE CLEAR SIGNAL IS FOR AN ENHANCED
CONVERGENCE BAND TO SKIRT FAR NORTHERN CHIPPEWA COUNTY...MAINLY
TOWARD PARADISE/WHITEFISH POINT...WITH MAYBE A COUPLE INCHES
POSSIBLE. FARTHER SOUTH...LOOKING LIKE PERSISTENT MORE NEBULOUS SNOW
SHOWERS WILL CONTINUE OVERNIGHT FOR SOUTHWEST FLOW AREAS ACROSS
NORTHWEST LOWER UP TOWARD DRUMMOND ISLAND. WAS A LITTLE CONCERNED
ABOUT SOME DRIZZLE POSSIBILITIES GIVEN INITIALLY SHALLOW NATURE OF
MOISTURE...BUT GRADUAL INTRUSION OF COLDER AIR ALOFT SHOULD FAVOR
ICE IN THE CLOUDS AS CLOUD TOP TEMPS END UP AROUND -12C BY 06Z. NO
MAJOR ACCUMULATION FORESEEN FOR NORTHERN LOWER OVERNIGHT.
&&
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 449 AM EST MON NOV 25 2013
A VERY ACTIVE AND RAPIDLY CHANGING WEATHER PATTERN WILL REMAIN
LOCKED IN ACROSS THE GREAT LAKES THROUGH THE THANKSGIVING HOLIDAY
WITH A SERIES OF SHORTWAVES AND SHOTS OF COLDER CANADIAN AIR
RESULTING IN A COUPLE OF ROUNDS OF LAKE EFFECT AND LAKE ENHANCED
SNOWFALL. THIS WILL ALSO PREVENT US FROM ANY SIGNIFICANT WARMING FOR
THE NEXT SEVERAL DAYS. A FAIRLY QUIET PERIOD OF WEATHER IS THEN
ANTICIPATED FOR FRIDAY THROUGH THE WEEKEND.
TUESDAY THROUGH WEDNESDAY NIGHT...A SIMILAR SET UP LIKE TODAY...IS
EXPECTED FOR TUESDAY WITH NEXT VIGOROUS SHORTWAVE...COLD FRONT AND
DEEPER MOISTURE ANTICIPATED TO MOVE IN ACROSS NRN MICHIGAN. THIS
TIME AROUND...WE WILL HAVE A BIT DEEPER INSTABILITY BUT LESS WIND.
WEST/WSW FLOW AHEAD OF THIS FRONT...H8 TEMPS COLDER IN THE -10C TO
-11C RANGE AND INVERSION HEIGHTS TO 7KFT WILL INCREASE TO NEAR 9KFT
WITH COLD ADVECTION THROUGH THE DAY...BUT A DRAMATIC SHIFT IN WINDS
TO OUT OF THE NNW INTO TUESDAY EVENING. MOISTURE IN THE LOWEST
LEVELS ARE STARTING TO LOOK A BIT MORE MOISTURE...MORE SO ON THIS
RUN OF THE BUFR SOUNDINGS. THE MOST IMPRESSIVE LES PARAMETERS ARE
REALLY FOCUSED TUESDAY EVENING AFTER THE FLOW TURNS NORTHERLY WITH
DEEPEST INSTABILITY WITH PASSAGE OF UPPER TROUGH AXIS/COLD AIR
ALOFT. THIS WILL FOCUS THE BEST ACCUMULATION POTENTIAL ACROSS THE
GTV BAY REGION AND AREAS SOUTH...WHERE ALSO...GUSTY WINDS COULD
LEAD TO BLOWING AND DRIFTING ISSUES. A CONSERVATIVE 3-6 INCHES OF
SNOW WILL BE POSSIBLE IN THIS REGION TUESDAY-TUESDAY NIGHT...LEADING
TO THE MOST HAZARDOUS DRIVING CONDITIONS EXPECTED IN THE LONG TERM
PORTION OF THE FORECAST. THE AIR MASS DRIES WITH LOWERING INVERSION
HEIGHTS INTO WEDNESDAY...HOWEVER CONTINUED COLD ADVECTION AND BEST
FETCH INTO GTV BAY WILL LEAD TO ANOTHER 1-2 INCHES OF SNOW
THERE...WHILE AMOUNTS ARE LESS IMPRESSIVE ELSEWHERE. FAR NE LOWER
NEAR ROGERS CITY/ALPENA AND OSCODA WILL SEE A SMATTERING OF 1 TO
MAYBE 3 INCH LOCAL AMOUNTS TUESDAY NIGHT INTO WEDNESDAY. WEDNESDAY
NIGHT...INVADING HIGHER PRESSURE AND LIGHTER WINDS FOR A LESSER
THREAT TO ANYTHING SIGNIFICANT IN THE SNOW DEPARTMENT.
HOWEVER...WILL HAVE TO KEEP AN EYE ON NEXT INCOMING SHORTWAVE AND
WARM ADVECTION OVER THE TOP OF THE REMAINING INSTABILITY...ALTHOUGH
MOST AREAS...LOOK TO HAVE A DISCONNECT FROM THE MOISTURE AND
ENHANCEMENT SEEDED FROM ALOFT. SLOWLY BACKING LOW LEVEL WINDS WILL
FOCUS ANY EMERGING THREAT OF RENEWED SNOW IN AND AROUND LAKE
MICHIGAN.
THANKSGIVING DAY AND NIGHT...THIS INCOMING WAVE IS RATHER WEAK
COMPARED TO IT`S PREDECESSORS....ALTHOUGH THE WARM ADVECTION/SEEDING
ALOFT DOES LOOK TO STILL HAVE SOME SORT OF ENHANCEMENT TO THE LAKE
EFFECT THROUGH THE HOLIDAY AND THURSDAY NIGHT. WINDS ARE EXPECTED TO
BE FAIRLY LIGHT...AND NOW SHIFTING ALL AROUND TO THE SW AS THIS
ENHANCEMENT PROCESS IN UNDERWAY...SPREADING SNOWS AROUND LAKE
MICHIGAN WITH LESS INLAND PENETRATION. THESE FINER DETAILS WILL
REALLY HAVE TO BE EXAMINED FURTHER OVER THE NEXT COUPLE OF DAYS TO
PROVIDE A MORE DETAILED HOLIDAY FORECAST. WIND DIRECTIONS AND SPEEDS
BEING THE MOST CRUCIAL...WHICH HAS A BIT OF UNCERTAINTY.
FRIDAY THROUGH SUNDAY...THIS WEAKER WAVE EXITS FRIDAY WITH SHALLOW
MID LEVEL RIDGING...AHEAD OF NEXT ADVERTISED SHORTWAVE ARRIVING
SATURDAY. A WEAK COLD FRONT LAYS ACROSS/WASHES OUT OVER NRN
MICHIGAN. COULD BE ONE LAST HOORAH OF SOME WEAKER LAKE EFFECT...BUT
THIS APPEARS TO BE THE LEAST OF CONCERN IN THE SERIES OF LAKE EFFECT
EVENTS. THIS MAINLY DUE TO THE CONTINUED LOW LEVEL WARM ADVECTION
AND GRADUAL EROSION OF THE OVERLAKE INSTABILITY. WILL HAVE RATHER
SMALL CHANCES FOR SNOW IN AND AROUND LAKE MICHIGAN IN THE SW FLOW
THAT PERSISTS INTO SUNDAY. TEMPERATURES WILL MODERATE BACK INTO THE
LOWER HALF OF THE 30S OVER THE WEEKEND.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1159 PM EST SUN NOV 24 2013
MAINLY VFR UNTIL MONDAY MORNING...THOUGH WITH LLWS AND/OR GUSTY
SW WINDS. CIGS/VSBY RESTRICTIONS ARRIVE IN -SHSN FROM NORTH TO
SOUTH MONDAY MORNING.
LOW PRESSURE NOW ALONG MANITOBA/ONTARIO BORDER WILL PASS JUST NORTH OF
SUPERIOR ON MONDAY. SW WINDS ARE INCREASING JUST OFF THE DECK
AHEAD OF THE LOW...RESULTING IN LLWS AT ALL TAF SITES
OVERNIGHT (GIVING WAY TO GUSTY SW WINDS BEFORE DAWN PLN/MBL).
SNOW WILL RE-DEVELOP MONDAY MORNING...1ST AT PLN...EVENTUALLY
IMPACTING ALL TAF SITES. MVFR TO IFR CONDITIONS EXPECTED AT TIMES
IN SHSN/BLSN...THOUGH WITH CONSIDERABLE VARIABILITY.
GUSTY SW WINDS ALL DAY MONDAY...LIGHTENING UP AND VEERING A BIT TO
THE WEST TOWARD EVENING.
&&
.MARINE...
ISSUED AT 449 AM EST MON NOV 25 2013
A WINDY ONE OUT THERE TO START...WITH GALES FOR MOST OF THE WATERS.
THOSE WINDS WILL SUBSIDE LATER THIS AFTERNOON AND ESPECIALLY THIS
EVENING...THOUGH WILL REMAIN A BIT GUSTY IN THE 20-25 KNOT RANGE AS
IS TYPICAL FOR LATE NOVEMBER. WINDS WILL GRADUALLY COME AROUND TO
THE NORTHWEST ON TUESDAY AND THEN NORTH TUESDAY NIGHT AND
WEDNESDAY...WITH CONTINUED GUSTS OF 25-30 KNOTS EXPECTED. COULD SEE
A PERIOD OF GALES ON MAINLY LAKE MICHIGAN SOMETIME TUESDAY NIGHT...
BUT CONFIDENCE IN THAT IS LOW AT THIS TIME. HIGH PRESSURE WILL
FINALLY WIN THE BATTLE BY THURSDAY...WITH A RETURN TO A BRIEF PERIOD
OF MUCH LIGHTER WINDS OF THE 15 KNOTS OF LESS VARIETY.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...WIND ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR MIZ015-016-019-
020-025-031.
LH...GALE WARNING UNTIL 10 PM EST THIS EVENING FOR LHZ345>349.
LM...GALE WARNING UNTIL 10 PM EST THIS EVENING FOR LMZ323-341-342-
344>346.
LS...SMALL CRAFT ADVISORY UNTIL 10 PM EST THIS EVENING FOR LSZ321-322.
&&
$$
SYNOPSIS...DL
SHORT TERM...DL
LONG TERM...SD
AVIATION...JZ
MARINE...DL
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
345 AM CST MON NOV 25 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 327 AM CST MON NOV 25 2013
A WEAK COLD FRONT CURRENTLY MOVING THROUGH SRN SOUTH DAKOTA
SHOULD CLEAR THE FORECAST AREA BY 21Z. A STRONG THERMAL RIDGE IS
RUNNING OUT AHEAD OF THE COLD FRONT WITH SFC TEMPS RISING INTO THE
UPPER 30S. THIS SHOULD MIX OUT THE ATMOSPHERE AND GIVE A HEAD
START TO MAX TEMPS IN THE 40S. THIS IS CLOSE TO THE RAP MODEL
WHICH WAS THE WARMEST SOLN NEXT TO THE ECM GUIDANCE FORECASTING
HIGHS IN THE MID AND UPPER 40S. SOME MID LEVEL CLOUDINESS
ASSOCIATED WITH THE COLD FRONT WOULD SUGGEST USING A FCST SLIGHTLY
COOLER THAN THE VERY WARM ECM GUIDANCE.
FOR TONIGHT...A REINFORCING ARCTIC FRONT...CURRENTLY ACROSS NRN
SASKATCHEWAN WILL BE MOVING THROUGH SD WITH A WEAK THERMAL RIDGE
RUNNING OUT AHEAD OF THIS FRONT. THE MODEL CONSENSUS SUGGESTED LOWS
IN THE TEENS WHICH MIGHT BE TOO COLD. THE MODELS APPEAR TO BE
PUSHING THIS FRONT INTO THE FCST AREA AROUND 06Z TONIGHT WITH H850
MB WINDS INCREASING TO 35 TO 40 KT WHICH WOULD SUPPORT MIXING
AND WARMER LOWS.
NO STRATUS IS EXPECTED WITH EITHER FRONT TODAY OR TONIGHT.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 327 AM CST MON NOV 25 2013
THE SOUTHERN PLAINS UPPER LEVEL LOW WILL PHASE TUESDAY WITH A
STRONG SHORTWAVE DROPPING SOUTHEAST THROUGH CANADA INTO THE GREAT
LAKES REGION. THIS WILL BRING HEAVY PRECIPITATION TO THE EAST
COAST WEDNESDAY. ACROSS OUR AREA...ANOTHER SHOT OF ARCTIC AIR
WILL PLUMMET SOUTH TUESDAY ON THE BACK SIDE OF THE DEVELOPING
EASTERN CONUS STORM. THIS WILL KEEP HIGHS IN THE 20S ONCE AGAIN
ACROSS PORTIONS OF NORTHERN NEBRASKA...WITH LOWER TO MID 30S
ACROSS THE PANHANDLE INTO SOUTHWEST NEBRASKA. THIS COLD AIR WILL
BE SHORT LIVED...AS UPPER LEVEL RIDGING AND A PACIFIC AIRMASS
SPREAD EAST THROUGH THE PLAINS STARTING WEDNESDAY. THE ECMWF HAS
BEEN ADVERTISING A CHINOOK EVENT WEDNESDAY...AND THIS SHOULD HELP
SCOUR OUT THE ARCTIC AIR. SHOULD SEE HIGHS INTO THE 40S ACROSS
WESTERN NEBRASKA...WITH LOWER 30S FARTHER EAST WHERE THE ARCTIC
AIR WILL BE MORE DENSE AND TAKE LONGER TO MIX OUT.
THE UPPER RIDGE BECOMES DOMINATE THANKSGIVING AND FRIDAY...WITH
DRY AND MILD CONDITIONS AREA WIDE. BY THE WEEKEND...THE UPPER
RIDGE WILL BEGIN TO FLATTEN...BUT IT REMAINS MILD AND DRY. MORE
COLD ARCTIC AIR IS POSSIBLE BEYOND THE FORECAST PERIOD AS WE HEAD
INTO NEXT WEEK...AS LARGE GULF OF ALASKA UPPER LEVEL LOW COULD
DROP SOUTHEAST INTO THE PACIFIC NORTHWEST. STAY TUNED.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1130 PM CST SUN NOV 24 2013
OVER THE NEXT 24 HOURS...EXPECT SCATTERED HIGH CLOUDINESS ACROSS
WESTERN AND NORTH CENTRAL NEBRASKA IN ASSOCIATION WITH AN UPPER
LEVEL TROUGH OF LOW PRESSURE TO THE NORTH AND A CLOSED LOW TO THE
SOUTH. CIGS WILL RANGE FROM 20000 TO 25000 FT AGL AT BOTH THE KVTN
AND KLBF TERMINALS. WINDS OVERNIGHT TONIGHT WILL BE FROM THE WEST OR
SOUTHWEST AT UNDER 10 KTS. WINDS WILL SHIFT TO THE NORTH MONDAY
MORNING INCREASING TO 10 TO 20 KTS MONDAY AFTERNOON...THEN
DECREASING TO UNDER 10 KTS MONDAY EVENING.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CDC
LONG TERM...TAYLOR
AVIATION...CLB
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1130 PM CST SUN NOV 24 2013
.SYNOPSIS...
ISSUED AT 235 PM CST SUN NOV 24 2013
AN UPPER LOW SPUN OVER THE FOUR CORNERS ON SUNDAY AFTERNOON...WHICH
PUSHED SOME MID AND HIGH LEVEL CLOUDS INTO SOUTHERN NEBRASKA. WITH
THE UPPER LOW TO THE SOUTH...WESTERLY FLOW ALOFT HAS ALLOWED FOR A
THERMAL RIDGE TO MOVE INTO THE NORTHERN PLAINS TODAY WHERE 850MB
TEMPERATURES WERE GENERALLY 5C TO 10C AS OF 12Z THIS MORNING
COMPARED TO 0C TO-5C ACROSS NEBRASKA. LOOKING AT WATER VAPOR...COULD
MAKE OUT THE NEXT LOW PRESSURE SYSTEM IN LINE IN THE NORTHWEST FLOW
OVER SASKATCHEWAN...WITH ANOTHER BATCH OF COLD ARCTIC AIR BEHIND IT.
&&
.SHORT TERM...(THIS AFTERNOON THROUGH MONDAY)
ISSUED AT 235 PM CST SUN NOV 24 2013
THE UPPER LEVEL LOW OVER THE FOUR CORNERS IS EXPECTED TO START
GETTING INFLUENCED BY THE MEAN NORTHWEST FLOW AND START TO PUSH INTO
TEXAS BY THE END OF THE DAY MONDAY. THIS SHOULD ALLOW FOR THE MID
AND HIGH CLOUDS THAT HAVE BEEN SPINNING AROUND THIS SYSTEM INTO THE
SOUTHERN PART OF THE FORECAST AREA FOR THE PAST SEVERAL DAYS TO GET
PULLED SOUTHWARD AND AWAY FROM THE LOCAL AREA TONIGHT AND MONDAY
MORNING. IT WILL ALSO ALLOW FOR SOME OF THE COLDER AIR ASSOCIATED
WITH THAT SYSTEM TO GET PUSHED AWAY FROM THE AREA. MEANWHILE...THE
LOW PRESSURE SYSTEM OVER SASKATCHEWAN WILL MOVE INTO ONTARIO WHICH
WILL DRAG A COLD FRONT ACROSS NEBRASKA TONIGHT AND MONDAY MORNING.
ALTHOUGH TEMPERATURES BEHIND THE FRONT WON/T BE MUCH COLDER FOR THE
LOCAL AREA. WINDS WILL SWITCH TO THE NORTH-NORTHWEST BEHIND THE
FRONT. FORECAST SOUNDINGS ARE SHOWING MINIMAL MIXING MONDAY
AFTERNOON...BUT WINDS JUST ABOVE THE SURFACE ARE ABOUT 25KTS SO
COULD SEE SOME 20KT WINDS AT GROUND LEVEL DURING THE AFTERNOON.
ONE CONCERN WITH THE FORECAST WILL BE THE POTENTIAL FOR THE
DEVELOPMENT OF SHALLOW STRATUS THIS EVENING AND TONIGHT FROM
SOUTHWEST INTO CENTRAL NEBRASKA. LOW LEVEL MOISTURE ADVECTION IS
BEING INDICATED INTO THE AREA AHEAD OF THE FRONT BY SEVERAL FORECAST
MODELS...WITH THE NAM BEING THE MOST ROBUST SPREADING STRATUS ACROSS
THE ENTIRE FORECAST AREA. DISCOUNTING THAT MODEL AND LOOKING CLOSER
TO THE RAP WHICH HAS BEEN HOLDING OFF THE LOW LEVEL MOISTURE FROM
MOVING INTO NEBRASKA THROUGH THE DAY TODAY. ALTHOUGH IT HAS KEPT
THIS MOISTURE SOUTH TODAY...IT DOES CONTINUE TO PUSH IT INTO
NEBRASKA THIS EVENING...WITH CLOUDS REMAINING UNTIL THE FRONT PUSHES
THROUGH LATE TONIGHT AND MONDAY MORNING. WATCHING THE STRATUS
STRUGGLE TO DEVELOP IN UPSTREAM AREAS TODAY...AND WITH THE RAP
CONTINUOUSLY BACKING OFF ON THE TIMING OF BRINGING IT NORTH...JUST
DON/T HAVE THE CONFIDENCE THAT THE CLOUDS WILL GET INTO THE LOCAL
AREA TONIGHT AND THE FORECAST TAKES THAT INTO ACCOUNT. IF THE
STRATUS DOES MOVE IN...MAY HAVE TO TAKE A LOOK AT LOW TEMPERATURES
TONIGHT...ALTHOUGH THEY SHOULDN/T HAVE AN IMPACT ON HIGHS MONDAY AS
THEY WOULD BE PUSHED OUT OF THE AREA BEFORE PEAK HEATING.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 235 PM CST SUN NOV 24 2013
A REINFORCING SHOT OF ARCTIC AIR WILL MOVE THROUGH THE DAKOTAS
INTO NEBRASKA MONDAY NIGHT AND TUESDAY. THIS WILL BRING A GLANCING
BLOW OF COLDER AIR...WHICH IS ACTUALLY NOT AS COLD AS THE PREVIOUS
ONE SATURDAY. WENT A FEW DEGREES ABOVE GUIDANCE LOWS MONDAY NIGHT
WITH MID/UPPER TEENS. WEAK COLD AIR ADVECTION TUESDAY WITH H85
TEMPS AS LOW AS -15C PER NAM MODEL. THIS LOOK TOO COLD AND FAVORED
THE GFS -11C. USING CONSALL INTO A BLEND HIGHS NEAR 25 AT ONL TO
36 AT IML. TEMPERATURES THEN WARMUP FOR WEDNESDAY. AS SURFACE HIGH
SLIDES EAST...A RETURN SOUTH TO SOUTHWEST FLOW DEVELOPS. WHILE
HIGHS TO BE LIMITED TO NEAR 30 AT BBW AND ONL...THE WESTERN TIER
OF COUNTIES TO WARM TO 40-43 DEGREES. DRY CONDITIONS TO ALSO PREVAIL.
FOR THANKSGIVING DAY THROUGH THE WEEKEND...DRY AND SEASONAL
TEMPERATURES ARE FORECAST. THE UPPER FLOW WILL REMAIN FAIRLY
ZONAL. THIS HIGHLIGHTED BY AN UPPER TROUGH DIGGING FROM BRITISH
COLUMBIA INTO THE NORTHERN PLAINS AND A CLOSED LOW REMAINING OFF
THE CALIF. COAST. ONLY A WEAK COLD FRONT INDICATED FRIDAY
NIGHT...WHICH SHOULD HAVE MINIMAL IMPACT TO HIGHS SATURDAY AND
SUNDAY. ONLY VERY MINOR CHANGES TO HIGHS THROUGH THIS WEEKEND WITH
MAINLY UPPER 30S TO MID 40S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1130 PM CST SUN NOV 24 2013
OVER THE NEXT 24 HOURS...EXPECT SCATTERED HIGH CLOUDINESS ACROSS
WESTERN AND NORTH CENTRAL NEBRASKA IN ASSOCIATION WITH AN UPPER
LEVEL TROUGH OF LOW PRESSURE TO THE NORTH AND A CLOSED LOW TO THE
SOUTH. CIGS WILL RANGE FROM 20000 TO 25000 FT AGL AT BOTH THE KVTN
AND KLBF TERMINALS. WINDS OVERNIGHT TONIGHT WILL BE FROM THE WEST OR
SOUTHWEST AT UNDER 10 KTS. WINDS WILL SHIFT TO THE NORTH MONDAY
MORNING INCREASING TO 10 TO 20 KTS MONDAY AFTERNOON...THEN
DECREASING TO UNDER 10 KTS MONDAY EVENING.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BROOKS
SHORT TERM...BROOKS
LONG TERM...ROBERG
AVIATION...CLB
AREA FORECAST DISCUSSION
NWS TULSA OK
1117 PM CST SUN NOV 24 2013
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
NEXT ROUND OF WINTER PRECIPITATION DEVELOPING OVER NORTH TEXAS
WILL SPREAD NE OVERNIGHT INTO SE OKLAHOMA AND EVENTUALLY NW
ARKANSAS BY 12Z WITH WIDESPREAD MVFR CONDITIONS DEVELOPING.
TEMPERATURE PROFILES CONTINUE TO SUPPORT MIX OF SLEET/SNOW WHICH
WILL EVENTUALLY TRANSITION TO LIQUID BEFORE ENDING IN THE
AFTERNOON. NE OKLAHOMA SITES SHOULD SEE SOME IMPROVEMENT IN
CEILINGS LATE IN THE PERIOD.
&&
.PREV DISCUSSION... /ISSUED 924 PM CST SUN NOV 24 2013/
..UPDATE...
DISCUSSION...
INITIAL WAVE OF MIXED WINTRY PRECIP HAS EXITED
THE FORECAST AREA...WITH SEVERAL EARLIER REPORTS
OF SLICK SPOTS/SLIDE-OFFS ACROSS SE OK/WCNTRL AR.
NEXT ROUND OF WINTER PRECIP IS CURRENTLY ORGANIZING
ACROSS NRN TX...AND PRECIP WILL BEGIN TO EXPAND
TO THE ENE OVERNIGHT AS ISENTROPIC LIFT (MOST NOTABLY
ALONG 300K SFC ATOP DRY LAYER) INCREASES. SFC TEMPS
ACROSS THE ADVISORY AREA ARE CURRENTLY RUNNING AROUND
28-32F...ALTHOUGH T/TD SPREADS SUGGEST SOME WET-BULBING
IS LIKELY ONCE PRECIP INCREASES IN COVERAGE/INTENSITY.
CURRENT FORECAST IS IN REASONABLE ENOUGH SHAPE...BUT
HAVE BUMPED UP POPS ACROSS THE SE AFTER 09Z...MORE
IN-LINE WITH LATEST HRRR OUTPUT. PRECIP MAY START AS
RAIN/SLEET ACROSS FAR SE OK...WITH A CHANGEOVER TO
SLEET...FREEZING RAIN AND POSSIBLY SOME SNOW LATER
TONIGHT. TRAVEL IMPACTS WILL MAINLY BE ON ELEVATED
ROAD SURFACES...BUT WILL NEED TO CLOSELY MONITOR SE OK.
UPDATED PRODUCTS OUT SHORTLY.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 27 36 26 43 / 40 30 10 0
FSM 29 35 30 44 / 60 60 20 10
MLC 28 35 27 42 / 60 60 20 10
BVO 26 37 24 42 / 20 30 10 0
FYV 26 34 25 40 / 40 50 20 10
BYV 26 34 25 39 / 10 30 20 10
MKO 27 35 26 42 / 50 50 10 10
MIO 27 36 24 41 / 10 20 10 0
F10 26 35 26 41 / 60 40 10 10
HHW 29 35 31 43 / 80 90 40 20
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...WINTER WEATHER ADVISORY UNTIL NOON MONDAY FOR OKZ049-OKZ053-
OKZ071-OKZ072-OKZ073-OKZ074-OKZ075-OKZ076.
AR...WINTER WEATHER ADVISORY UNTIL NOON MONDAY FOR ARZ019-ARZ020-
ARZ029.
&&
$$
SHORT TERM...99
LONG TERM....99
AVIATION...14
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1137 PM CST SUN NOV 24 2013
.UPDATE...
ISSUED AT 933 PM CST SUN NOV 24 2013
THE MAIN FOCUS TONIGHT HAS BEEN ON THE PRECIPITATION TYPE AND
CHANCES OVERNIGHT INTO TOMORROW MORNING. CURRENTLY...THERE IS ONE
LEAD MID LEVEL SHORTWAVE TROUGH DROPPING SOUTH ACROSS CENTRAL
MINNESOTA AND NORTHERN WISCONSIN WITH ANOTHER SYSTEM IN THE
CENTRAL PLAINS. RADAR RETURNS WITH THE MN/WI TROUGH DO NOT APPEAR
TO BE REACHING THE GROUND DUE TO SOME DRY LOW TO MID LEVEL AIR
THAT IS IN PLACE ACCORDING TO 25.00Z MPX/GRB/ABR RAOBS. THE RADAR
RETURNS IN SOUTHWEST IOWA ALSO DO NOT APPEAR TO BE REACHING THE
GROUND AS WELL THANKS TO THIS DRY LOW LEVEL AIR. SO...WHILE CLOUD
COVER WILL BE ON THE INCREASE...IT APPEARS THAT THE REST OF THE
EVENING WILL BE DRY.
THE MAIN CHANCES FOR ANY PRECIPITATION LOOKS TO BE BETWEEN 3AM AND
9AM TOMORROW MORNING AS THESE TWO SYSTEMS CONVERGE ON THE AREA.
HAD HOPED TO HAVE A BETTER HANDLE ON WHETHER THERE WILL BE ICE
PRESENT AS THE LIFT COMES IN...BUT THE PAST FEW RUNS OF THE RAP
HAVE GONE BACK AND FORTH ON WHETHER THERE WILL BE ANY ICE. THIS
LEADS TO CONFIDENCE NOT BEING HIGH ENOUGH TO MOVE FORWARD ON A
POTENTIAL ADVISORY FOR FREEZING DRIZZLE SINCE THE POSSIBILITY IS
THERE THAT IT WOULD JUST BE A BRIEF PERIOD OF LIGHT SNOW.
OTHERWISE...WINDS HAVE REMAINED GUSTY THROUGHOUT THE REGION AS THE
PRESSURE GRADIENT IS STILL VERY TIGHT BETWEEN THE RETREATING HIGH
OVER THE OHIO RIVER VALLEY AND THE APPROACHING TROUGH IN THE
NORTHERN PLAINS.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 201 PM CST SUN NOV 24 2013
MAIN SHORT TERM FORECAST CONCERN IS ON PRECIPITATION CHANCES LATER
TONIGHT...ALONG WITH HOW MUCH AND POTENTIAL FOR FREEZING DRIZZLE.
CURRENTLY AS OF 20Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED RIDGING ALONG THE WEST COAST OF NORTH AMERICA...SUBTROPICAL
STREAM TROUGH OVER ARIZONA...AND NORTHERN STREAM TROUGHING FROM
CENTRAL CANADA INTO NEW ENGLAND. WITHIN THIS TROUGHING...A FAIRLY
POTENT SHORTWAVE WAS SEEN DIVING SOUTHEAST THROUGH SASKATCHEWAN.
AHEAD OF THIS TROUGH...VAD WIND PROFILES DEPICT 30-45 KT 925MB WINDS
ACROSS THE EASTERN DAKOTAS AND MINNESOTA. THESE WINDS HAVE BEEN
ADVECTING WARMER AIR TOWARDS THE FORECAST AREA...WITH 925MB TEMPS
NOW PER RAP ANALYSIS AT -7 TO -12C...COMPARED TO -12 TO -14C AT 12Z.
AIRMASS REMAINS RELATIVELY DRY...THOUGH...WITH PRECIPITABLE WATER
VALUES JUST BELOW 0.25 INCH ACROSS THE UPPER MIDWEST. UPSTREAM IN
THE WAKE OF THE SHORTWAVE...ANOTHER ARCTIC AIR SURGE WAS BREWING
ACROSS THE NORTHWEST TERRITORIES WHERE TEMPERATURES ARE SITTING IN
THE SINGLE DIGITS AND TEENS ABOVE ZERO.
MODELS ARE IN GOOD AGREEMENT SLIDING THE POTENT SHORTWAVE OVER
SASKATCHEWAN SOUTHEAST INTO NORTHERN PORTIONS OF MN...WI AND MI
MONDAY MORNING...THEN HEADING OFF TO EASTERN ONTARIO DURING THE
AFTERNOON. AS THE SHORTWAVE APPROACHES TONIGHT...SFC/925/850MB WINDS
ALL INCREASE OVER THE FORECAST AREA...SETTING UP FOR A MUCH WARMER
NIGHT. IN ADDITION...THESE WINDS WILL ADVECT IN A TONGUE OF
RELATIVELY HIGHER MOISTURE FROM WESTERN KS AND EASTERN COLORADO...AS
WELL AS FROM UP IN SOUTHERN MANITOBA...NOTED BY PRECIPITABLE WATER
CLIMBING TO AROUND 0.5 INCH. THE HIGHEST PRECIPITABLE WATER IS
CONFINED TO NORTHEAST IOWA AND SOUTHERN WI WHICH WOULD THEREFORE BE
THE GREATEST CONCERN FOR PRECIPITATION. ALBEIT...THE GENERAL LOW
AMOUNT OF PRECIPITABLE WATER WILL LIKELY LIMIT THE AMOUNT OF
PRECIPITATION. REGARDING LIFT...280-290K ISENTROPIC SURFACES DEPICT
AN INCREASE OF NET ADIABATIC OMEGA ACROSS THE FORECAST AREA BETWEEN
06 AND 12Z...THEN SLIDES OFF TO THE SOUTHEAST. GENERAL MODEL
CONSENSUS HAS BEEN HOLDING STEADY SUGGESTING PRECIPITATION BREAKING
OUT ACROSS NORTHEAST IOWA LATE TONIGHT...THEN SPREADING INTO
SOUTHERN AND PERHAPS CENTRAL WISCONSIN MONDAY MORNING. SINCE
SATURATION OCCURS FROM THE LOW TO MID LEVELS OF THE ATMOSPHERE...THE
PRECIPITATION TYPE SHOULD BE MOSTLY SNOW...BUT CANNOT RULE OUT SOME
FREEZING DRIZZLE POSSIBLE EITHER AT THE ONSET OR ON THE NORTH SIDE
OF THE DEEPER MOISTURE. ANOTHER CONCERN IS PRECIPITATION BREAKING
OUT ALONG THE POTENT SHORTWAVES WARM FRONT. 24.12Z GFS/HIRESARW AND
24.15Z SREF ALL SUGGEST THAT AS THE FRONT RUNS INTO LOW LEVEL
STRATUS WHICH DEVELOPED LATE TONIGHT AHEAD OF IT...VERTICAL MOTION
WITH THE FRONT CAN PRODUCE LIGHT PRECIPITATION. THIS WOULD APPEAR TO
BE THE BEST CHANCE TO SEE FREEZING DRIZZLE. MUCH OF THE FORECAST
AREA WOULD HAVE A CONCERN FOR THIS DEVELOPING...INCLUDING NORTHEAST
IA AND SOUTHERN WI WHEN THE SNOW THERE DEPARTS.
GIVEN THAT THE PROBABILITY OF FREEZING DRIZZLE IS LOW AT THIS
TIME...ON THE ORDER OF 20 TO MAYBE 30 PERCENT...HAVE NOT ISSUED ANY
WINTER WEATHER ADVISORIES. FURTHER SHIFTS MAY NEED TO ISSUE
THEM...THOUGH...IF FREEZING DRIZZLE LOOKS MORE LIKELY TO OCCUR.
TEMPERATURE WISE...WE SHOULD SEE TEMPERATURES HOLD EITHER NEARLY
STEADY AND LIKELY RISE AFTER MIDNIGHT AS THE BREEZY SOUTH WINDS
BRING IN WARMER AIR AT THE SURFACE. THERE IS POTENTIAL FOR SOME
CLEARING MONDAY AFTERNOON...WHICH WITH 925MB TEMPS WARMING TO -2 TO -
4C IN THE AFTERNOON...HIGHS SHOULD CLIMB INTO THE 30S IN MOST
LOCATIONS.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 201 PM CST SUN NOV 24 2013
FOCUS OF THE LONG TERM PERIOD IS ON AN ARCTIC COOL SHOT SLATED FOR
TUESDAY INTO WEDNESDAY...AND ANY POSSIBLE PRECIPITATION THURSDAY
INTO THE WEEKEND.
MODELS DEPICT ANOTHER POTENT SHORTWAVE DROPPING OUT OF THE NORTHWEST
TERRITORIES AND DOWN INTO THE FORECAST AREA ON TUESDAY. THIS POTENT
SHORTWAVE REALLY HELPS TO BRING DOWN THE ARCTIC AIR OBSERVED UP
THERE. AT THE SAME TIME...WITH THE ARCTIC COLD FRONTAL PASSAGE
OCCURRING IN THE MORNING...LOW LEVEL MOISTURE GETS TRAPPED. THIS
MOISTURE COMBINED WITH DAYTIME HEATING WILL MANIFEST ITSELF INTO A
FAIRLY WIDESPREAD STRATUS DECK. STEEP LOW LEVEL LAPSE RATES ALONG
WITH THE STRATUS DECK BEING IN THE DENDRITIC GROWTH ZONE IS LIKELY
TO LEAD TO FLURRIES AT A MINIMUM...AND WOULD NOT BE SURPRISED IF
SOME LOW CHANCES OF PRECIPITATION WILL NEED TO BE ADDED.
WITH THE ARCTIC COLD FRONTAL PASSAGE TUESDAY MORNING...EXPECT
TEMPERATURES TO NOT RISE MUCH AND IF ANYTHING WILL LIKELY FALL
DURING THE AFTERNOON HOURS. 925MB TEMPS FALL TO -12C BY 00Z
WEDNESDAY AND TO AROUND -14C BY 12Z WEDNESDAY. THERE IS A CONTINUING
NORTHWEST BREEZE THROUGH THIS PERIOD WHICH WILL TEMPER A BIT ON HOW
COLD WE GET TUESDAY NIGHT...AND LEANED MORE TOWARDS THE MET GUIDANCE
FOR LOWS. ON THE FLIP SIDE...EXPECT COLDER WIND CHILLS BECAUSE OF
THE BREEZE. SOME MODERATION TAKES PLACE IN 925MB TEMPS ON WEDNESDAY
WITH SUN SO THAT TEMPERATURES CAN CLIMB BACK INTO THE LOW TO MID
20S.
THE UPPER FLOW FROM THANKSGIVING AND BEYOND LOOKS TO CHANGE...GOING
FROM THE NORTHWESTERLY PATTERN WE HAVE BEEN IN RECENTLY TOWARDS MORE
ZONAL. THERE ARE EVEN HINTS IN THE 24.12Z ECMWF OF THE FLOW BACKING
SOUTHWESTERLY EARLY NEXT WEEK. THIS PATTERN CHANGE WILL HELP
DISLODGE SOME OF THE COLD AIR...THUS FOLLOWED A CONSENSUS FORECAST
DEPICTING A GRADUAL MODERATING TREND FOR TEMPERATURES. REGARDING
PRECIPITATION CHANCES...DURING THE PATTERN CHANGE...THERE ARE
SHORTWAVE TROUGHS TRAVERSING ACROSS NORTHERN MN INTO UPPER MI ON
THANKSGIVING AND ON SATURDAY. RIGHT NOW BASED ON THE TRACK WOULD
SUGGEST THE BETTER CHANCES FOR PRECIPITATION WOULD STAY NORTH OF THE
FORECAST AREA. HOWEVER...THAT SATURDAY SHORTWAVE TROUGH APPEARS TO
TAKE A BIT FARTHER SOUTH TRACK COMPARED TO THE ONE ON
THANKSGIVING...THUS 20 PERCENT CHANCES OF SNOW ARE IN THE
FORECAST FOR BOTH SATURDAY AND SATURDAY NIGHT. FRIDAY AND SUNDAY
APPEAR DRY AT THIS TIME BETWEEN SHORTWAVE TROUGHS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1137 PM CST SUN NOV 24 2013
AS TWO SYSTEMS MERGE ACROSS THE REGION OVERNIGHT INTO MONDAY
MORNING...CHANCES FOR PRECIPITATION WILL BE RISE WITH FLIGHT
CONDITIONS LOWERING. THE MAIN PERIOD OF CONCERN IS BETWEEN 6AM AND
NOON WHEN MOISTURE DEEPENS AND THE LIFT BECOMES STRONGER.
CONFIDENCE IS NOT VERY HIGH WITH WHETHER THE POTENTIAL
PRECIPITATION TYPE WILL BE SNOW OR FREEZING DRIZZLE...BUT THE
CHANCES LOOK HIGHER THAT IT WILL BE FREEZING DRIZZLE AT LSE. RST
MAY NOT SEE ANY...SO HAVE TAKEN IT OUT OF THEIR TAF. CEILINGS WILL
LIKELY DROP TO MVFR/IFR AS THIS PRECIPITATION STARTS UP MONDAY
MORNING. WINDS HAVE REMAINED GUSTY THROUGH THE REGION WITH LOW
LEVEL WIND SHEAR CRITERIA LIKELY NOT BEING MET AT RST WITH WINDS
GUSTING TO 30-40KTS AT THE SURFACE. CONDITIONS ARE EXPECTED TO
IMPROVE INTO MONDAY NIGHT AS DRIER AIR MOVES IN.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...HALBACH
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...HALBACH
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1002 AM CST MON NOV 25 2013
.DISCUSSION...
323 AM CST
WITH NOVEMBER LOOKING TO FINISH WITH CONTINUED BELOW NORMAL
TEMPERATURES DURING ITS FINAL WEEK WITH LITTLE IN THE WAY OF SHARP
THERMAL CHANGES...THE PRIMARY FOCUS OF THE FORECAST WAS ON THE LIGHT
SNOW EVENT TODAY AND THEN THE LAKE EFFECT SNOW POTENTIAL INTO
NORTHWEST INDIANA TUESDAY NIGHT AND WEDNESDAY.
SOMEWHAT SPLIT UPPER FLOW IS IN PLACE ACROSS THE CENTRAL U.S. THIS
MONDAY WITH A QUICKLY-MOVING TROUGH ACROSS ONTARIO DIVING INTO THE
GREAT LAKES BY AFTERNOON...AND A CLOSED LOW ACROSS THE TEXAS
PANHANDLE BRINGING RARE NOVEMBER WINTER WEATHER HEADLINES TO THE
SOUTHERN PLAINS. OUR FORECAST AREA BASICALLY FALLS BETWEEN THESE TWO
SYSTEMS TODAY AND AS A RESULT THERE IS A VOID OF ANY OVERLY STRONG
FORCING OVERHEAD. ISENTROPIC ASCENT AND SATURATION WITHIN THE WSW
FLOW ALOFT THIS MORNING LOOKS TO BE THE PRIMARY CONTRIBUTOR TO
PRECIPITATION GENERATION...ALTHOUGH DRY LOW-LEVELS MAY KEEP IT
FLURRIES THROUGH MID TO LATE MORNING OVER CHICAGO. AN AXIS OF
FRONTOGENESIS CENTERED TO THE NORTHWEST OF THE AREA FROM EASTERN IA
INTO SOUTHERN WI THROUGH ~10 AM ON THE RAP AND LOCAL ARW MAY RESULT
IN BETTER SNOWFALL CLIPPING THE ROCKFORD AREA THIS MORNING...AND
CONCEIVABLY COULD SEE AN INCH BECAUSE OF THAT BUT THAT WOULD SEEM
THE MAXIMUM. AS THE SUBTLE FORCING AND MID-LEVEL SATURATION EVOLVES
EAST INTO THE AFTERNOON...PERIODS OF LIGHT SNOW WILL LIKELY RESULT
IN ONE HALF INCH OR LESS FOR MOST COMMUNITIES...AND NAMELY NORTH OF
I-80. WHILE NOT THE MOST IDEAL SYNOPTIC SETUP FOR FREEZING
DRIZZLE...THERE ARE SOME SIGNS ON GUIDANCE THAT AS ICE INTRODUCTION
IS LOST DURING THE MID TO LATE AFTERNOON THAT THERE MAY BE A BRIEF
WINDOW FOR THIS. ASCENT LOOKS WEAK AND CLOUD BASES LOOK HIGH FOR
THAT TO OCCUR THOUGH...SO CONTINUE TO NOT MENTION IN FORECAST.
THE AMOUNT OF CLOUD COVER TODAY WILL ONLY ALLOW TEMPERATURES TO RISE
BY ADVECTION...AND THAT WILL BE MEAGER AT THE SURFACE. SO MAINTAIN
HIGHS MAINLY IN THE LOWER 30S...WHICH WOULD RESULT IN THE THIRD
STRAIGHT DAY OF DOUBLE DIGIT DEPARTURES BELOW NORMAL.
A SECOND MORE ROBUST NORTHERN STREAM WAVE...THAT ACTUALLY LOOKS TO
BE A CLOSED SUB 520DM H5 LOW...WILL DROP INTO THE GREAT LAKES ON
TUESDAY. A FAIRLY DEEP PV ANOMALY IS SEEN WITH THIS ALONG WITH H5
TEMPS DOWN TO NEAR -30C...WHICH COME BARRELING INTO THE FORECAST
AREA BY LATE AFTERNOON INTO THE EVE TUESDAY ON THE GUIDANCE SUITE.
AN ASSOCIATED SURFACE COLD FRONT LOOKS TO STEEPEN LAPSE RATES AND
COULD SUPPORT SOME SNOW SHOWERS. CERTAINLY SOME FLURRIES LOOK TO BE
PRESENT INTO TUESDAY NIGHT. LOWS THAT NIGHT LOOK TO RETURN TO THE
MID AND POSSIBLY EVEN LOWER TEENS IN OUTLYING LOCATIONS.
MORE OF A CONCERN IS TURNING TO A POTENTIAL PLOWABLE SNOW FROM LAKE
EFFECT GENERATION INTO NORTHWEST INDIANA TUESDAY NIGHT INTO THE
BUSIEST TRAVEL DAY OF THE YEAR ON WEDNESDAY. THERE REMAINS MODEL
DIFFERENCES ON HOW QUICKLY THE AFOREMENTIONED SOUTHERN PLAINS UPPER
LOW AND THIS GREAT LAKES LOW PHASE. BUT OVERALL THE FLOW ACROSS LAKE
MI SHOULD BECOME STIFF AND NORTHERLY BY LATER TUESDAY NIGHT. THERE
ARE EVEN SIGNS ON SOME HIGH RESOLUTION MODELS...INCLUDING OUR LOCAL
ARW...OF MESO-LOW DEVELOPMENT TRANSLATING SOUTH ACROSS THE LAKE ON
TUESDAY NIGHT. CONFIDENCE ON SUCH A FEATURE IS LOW AT THIS
POINT...AS IS WHETHER THERE WILL EXIST A FOCUSED BAND OR JUST
WIDESPREAD SHOWERS OFF THE LAKE. BUT CONFIDENCE IS HIGH THERE WILL
BE AT LEAST SNOW SHOWERS INTO NORTHWEST INDIANA GIVE THE FORECAST
TRAJECTORIES...STEEP LOW-LEVEL LAPSE RATES...LAKE-INDUCED CAPE OF
AROUND 500 J/KG...AND EQUILIBRIUM LEVELS FORECAST AROUND 9000 FT.
THESE INDICES ACTUALLY INDICATE SOMEWHERE COULD GET A ROBUST SNOW
EVENT WITH HEAVY RATES WHICH WOULD IMPACT WEDNESDAY TRAVEL. IN
ADDITION...USING THE CIPS ANALOGS INDICATES A FAIRLY STRONG
CORRELATED EVENT FOR 850MB TEMPERATURES AND LOW-LEVEL WIND FLOW ON
11/21/08 AND THAT PRODUCED OVER 8 INCHES JUST EAST OF THE AREA. AT
THIS TIME HAVE CONTINUED THE TREND OF PREVIOUS SHIFT IN INCREASING
POPS ACROSS PORTER AND EASTERN LAKE COUNTIES.
BEYOND THERE WAS LITTLE CHANGE TO THE FORECAST AS THE HOLIDAY ITSELF
LOOKS QUIET ACROSS THE AREA WITH GRADUALLY BUILDING HEIGHTS AND
SURFACE HIGH PRESSURE. A QUASI-ZONAL PATTERN IS FAVORED ON LONG
RANGE DETERMINISTIC MODELS AND ENSEMBLES...WHICH WOULD FAVOR A
GRADUAL MODERATION TO NEAR NORMAL FOR THE FIRST DAY OF
METEOROLOGICAL WINTER ON SUNDAY.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* GUSTY SOUTHWEST WINDS TODAY.
* PERIODS OF LIGHT SNOW LIKELY BEGINNING EARLY AFTERNOON THROUGH
MID TO LATE AFTERNOON WITH PERIODS OF MVFR TO IFR VIS AND MVFR
CIGS POSSIBLE.
* HAVE PUSHED BACK TIMING OF SNOW ONSET BY AN HOUR IN THE TAFS.
KREIN
//DISCUSSION...UPDATED 12Z...
THE MAIN FORECAST CONCERNS THIS MORNING CONTINUE TO REVOLVE AROUND
THE LIGHT SNOW EXPECTED ACROSS THE TERMINALS TODAY...ALONG WITH
THE STRONG SOUTHWESTERLY WINDS.
A STRONG PRESSURE GRADIENT IS SETTING UP ACROSS THE AREA EARLY THIS
MORNING IN ASSOCIATION WITH LOW PRESSURE ACROSS SOUTHERN ONTARIO AND
HIGH PRESSURE ACROSS THE SOUTHEASTERN CONUS. THIS WILL CONTINUE TO
SUPPORT GUSTY WINDS THROUGH THE DAY. OVERALL WINDS STILL APPEAR TO
BE SOUTHWESTERLY AROUND 15 TO 17 KT WITH GUSTS UP TO 25 TO 28 KT.
THE OTHER CONCERN IS THAT FOR LIGHT SNOW. SNOW IS BEGINNING TO FALL
ACROSS PORTIONS OF IOWA AND INTO NORTHWESTERN ILLINOIS THIS
MORNING. THIS ACTIVITY WILL TAKE SOME TIME TO MOVE ACROSS
NORTHEASTERN ILLINOIS AS THE LOWER LEVELS ARE STILL FAIRLY DRY.
HOWEVER...WITH TIME THIS MORNING THE LOWER LEVELS WILL MOISTEN TO
ALLOW SNOW TO START AFTER 16 UTC AT THE EASTERN TERMINALS AND A
COUPLE HOURS SOONER AT KRFD. OVERALL...THIS WILL NOT BE A BIG
SNOW MAKER. THERE WILL BE ABOUT A 4 TO 6 HOUR WINDOW FOR SOME
LIGHT SNOW. VISIBILITIES IN THE SNOW COULD DROP DOWN AROUND 2
MILES FOR A PERIOD AND SOME LIGHT ACCUMULATIONS UP TO A HALF INCH
ARE POSSIBLE...ESPECIALLY AT KRFD. THE SNOW CHANCES WILL END QUICKLY
BY MID TO LATE AFTERNOON AS DRYER AIR FILTERS IN ACROSS THE AREA.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* HIGH CONFIDENCE IN WINDS.
* MEDIUM CONFIDENCE IN PERIODS OF LIGHT SNOW WITH MVFR TO IFR VIS
AND MVFR CIGS.
* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...
TUESDAY NIGHT...FLURRIES IN THE EVENING WITH MVFR CIGS LIFTING TO
VFR.
WEDNESDAY...LAKE EFFECT MVFR CIGS PSBL.
THURSDAY AND FRIDAY...VFR.
SATURDAY...MVFR CIGS PSBL OVERNIGHT.
SUNDAY...MVFR CIGS PSBL
KJB
&&
.MARINE...
206 AM CST
A VERY ACTIVE WEATHER PATTERN WILL CONTINUE ACROSS THE GREAT LAKES
THROUGH MID WEEK. THE CURRENT GALE EVENT IS WELL UNDERWAY WITH
SEVERAL REPORTS OF 40+ KT WINDS...ESPECIALLY ACROSS THE NORTHERN
HALF OF THE LAKE. THESE GALES WILL CONTINUE THROUGH AT LEAST THE MID
AFTERNOON HOURS TODAY AS A AN AREA OF LOW PRESSURE TRACKS EASTWARD
ACROSS SOUTHERN ONTARIO. THE WINDS WILL GRADUALLY ABATE INTO THIS
EVENING. THE CURRENT GALE HEADLINE MAY BE ALOUD TO EXPIRE A FEW
HOURS EARLIER THAN THE CURRENT 9 PM DEADLINE. HOWEVER...AT THIS
POINT I WILL LEAVE THE HEADLINE TIMING ALONE.
THE NEXT ISSUE WILL BE LATER TUESDAY THROUGH MUCH OF WEDNESDAY. A
STRONG STORM SYSTEM IS EXPECTED TO MOVE UP THE EAST COAST DURING
THIS TIME...AND AS HIGH PRESSURE BUILDS IN ACROSS THE MISSOURI
VALLEY CONDITIONS WILL BECOME FAVORABLE FOR A PERIOD OF NORTHERLY
GALES UP TO 35 TO 40 KT. THIS LOOKS TO BE THE MOST PRONOUNCED ACROSS
SOUTHERN LAKE MICHIGAN...AND ANY LAKE EFFECT BANDS OF SNOW THAT
DEVELOP DURING THIS TIME COULD LEAD ALSO EVEN LEAD TO SOME LOCALLY
HIGH WINDS IN EXCESS OF 40 KT. IT APPEARS TO BE A GOOD BET THAT A
GALE HEADLINE WILL BE NEEDED DURING THIS TIME. I THREW AROUND THE
IDEA OF HOSTING A GALE WATCH FOR THIS PERIOD...BUT DUE TO THE FACT
IT IS STILL FAR ENOUGH OUT...I HAVE DECIDED TO LET THE CURRENT
GALE HEADLINES END PRIOR TO THE ISSUANCE OF A NEW HEADLINE.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 PM MONDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 9 PM MONDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
804 AM CST MON NOV 25 2013
.DISCUSSION...
323 AM CST
WITH NOVEMBER LOOKING TO FINISH WITH CONTINUED BELOW NORMAL
TEMPERATURES DURING ITS FINAL WEEK WITH LITTLE IN THE WAY OF SHARP
THERMAL CHANGES...THE PRIMARY FOCUS OF THE FORECAST WAS ON THE LIGHT
SNOW EVENT TODAY AND THEN THE LAKE EFFECT SNOW POTENTIAL INTO
NORTHWEST INDIANA TUESDAY NIGHT AND WEDNESDAY.
SOMEWHAT SPLIT UPPER FLOW IS IN PLACE ACROSS THE CENTRAL U.S. THIS
MONDAY WITH A QUICKLY-MOVING TROUGH ACROSS ONTARIO DIVING INTO THE
GREAT LAKES BY AFTERNOON...AND A CLOSED LOW ACROSS THE TEXAS
PANHANDLE BRINGING RARE NOVEMBER WINTER WEATHER HEADLINES TO THE
SOUTHERN PLAINS. OUR FORECAST AREA BASICALLY FALLS BETWEEN THESE TWO
SYSTEMS TODAY AND AS A RESULT THERE IS A VOID OF ANY OVERLY STRONG
FORCING OVERHEAD. ISENTROPIC ASCENT AND SATURATION WITHIN THE WSW
FLOW ALOFT THIS MORNING LOOKS TO BE THE PRIMARY CONTRIBUTOR TO
PRECIPITATION GENERATION...ALTHOUGH DRY LOW-LEVELS MAY KEEP IT
FLURRIES THROUGH MID TO LATE MORNING OVER CHICAGO. AN AXIS OF
FRONTOGENESIS CENTERED TO THE NORTHWEST OF THE AREA FROM EASTERN IA
INTO SOUTHERN WI THROUGH ~10 AM ON THE RAP AND LOCAL ARW MAY RESULT
IN BETTER SNOWFALL CLIPPING THE ROCKFORD AREA THIS MORNING...AND
CONCEIVABLY COULD SEE AN INCH BECAUSE OF THAT BUT THAT WOULD SEEM
THE MAXIMUM. AS THE SUBTLE FORCING AND MID-LEVEL SATURATION EVOLVES
EAST INTO THE AFTERNOON...PERIODS OF LIGHT SNOW WILL LIKELY RESULT
IN ONE HALF INCH OR LESS FOR MOST COMMUNITIES...AND NAMELY NORTH OF
I-80. WHILE NOT THE MOST IDEAL SYNOPTIC SETUP FOR FREEZING
DRIZZLE...THERE ARE SOME SIGNS ON GUIDANCE THAT AS ICE INTRODUCTION
IS LOST DURING THE MID TO LATE AFTERNOON THAT THERE MAY BE A BRIEF
WINDOW FOR THIS. ASCENT LOOKS WEAK AND CLOUD BASES LOOK HIGH FOR
THAT TO OCCUR THOUGH...SO CONTINUE TO NOT MENTION IN FORECAST.
THE AMOUNT OF CLOUD COVER TODAY WILL ONLY ALLOW TEMPERATURES TO RISE
BY ADVECTION...AND THAT WILL BE MEAGER AT THE SURFACE. SO MAINTAIN
HIGHS MAINLY IN THE LOWER 30S...WHICH WOULD RESULT IN THE THIRD
STRAIGHT DAY OF DOUBLE DIGIT DEPARTURES BELOW NORMAL.
A SECOND MORE ROBUST NORTHERN STREAM WAVE...THAT ACTUALLY LOOKS TO
BE A CLOSED SUB 520DM H5 LOW...WILL DROP INTO THE GREAT LAKES ON
TUESDAY. A FAIRLY DEEP PV ANOMALY IS SEEN WITH THIS ALONG WITH H5
TEMPS DOWN TO NEAR -30C...WHICH COME BARRELING INTO THE FORECAST
AREA BY LATE AFTERNOON INTO THE EVE TUESDAY ON THE GUIDANCE SUITE.
AN ASSOCIATED SURFACE COLD FRONT LOOKS TO STEEPEN LAPSE RATES AND
COULD SUPPORT SOME SNOW SHOWERS. CERTAINLY SOME FLURRIES LOOK TO BE
PRESENT INTO TUESDAY NIGHT. LOWS THAT NIGHT LOOK TO RETURN TO THE
MID AND POSSIBLY EVEN LOWER TEENS IN OUTLYING LOCATIONS.
MORE OF A CONCERN IS TURNING TO A POTENTIAL PLOWABLE SNOW FROM LAKE
EFFECT GENERATION INTO NORTHWEST INDIANA TUESDAY NIGHT INTO THE
BUSIEST TRAVEL DAY OF THE YEAR ON WEDNESDAY. THERE REMAINS MODEL
DIFFERENCES ON HOW QUICKLY THE AFOREMENTIONED SOUTHERN PLAINS UPPER
LOW AND THIS GREAT LAKES LOW PHASE. BUT OVERALL THE FLOW ACROSS LAKE
MI SHOULD BECOME STIFF AND NORTHERLY BY LATER TUESDAY NIGHT. THERE
ARE EVEN SIGNS ON SOME HIGH RESOLUTION MODELS...INCLUDING OUR LOCAL
ARW...OF MESO-LOW DEVELOPMENT TRANSLATING SOUTH ACROSS THE LAKE ON
TUESDAY NIGHT. CONFIDENCE ON SUCH A FEATURE IS LOW AT THIS
POINT...AS IS WHETHER THERE WILL EXIST A FOCUSED BAND OR JUST
WIDESPREAD SHOWERS OFF THE LAKE. BUT CONFIDENCE IS HIGH THERE WILL
BE AT LEAST SNOW SHOWERS INTO NORTHWEST INDIANA GIVE THE FORECAST
TRAJECTORIES...STEEP LOW-LEVEL LAPSE RATES...LAKE-INDUCED CAPE OF
AROUND 500 J/KG...AND EQUILIBRIUM LEVELS FORECAST AROUND 9000 FT.
THESE INDICES ACTUALLY INDICATE SOMEWHERE COULD GET A ROBUST SNOW
EVENT WITH HEAVY RATES WHICH WOULD IMPACT WEDNESDAY TRAVEL. IN
ADDITION...USING THE CIPS ANALOGS INDICATES A FAIRLY STRONG
CORRELATED EVENT FOR 850MB TEMPERATURES AND LOW-LEVEL WIND FLOW ON
11/21/08 AND THAT PRODUCED OVER 8 INCHES JUST EAST OF THE AREA. AT
THIS TIME HAVE CONTINUED THE TREND OF PREVIOUS SHIFT IN INCREASING
POPS ACROSS PORTER AND EASTERN LAKE COUNTIES.
BEYOND THERE WAS LITTLE CHANGE TO THE FORECAST AS THE HOLIDAY ITSELF
LOOKS QUIET ACROSS THE AREA WITH GRADUALLY BUILDING HEIGHTS AND
SURFACE HIGH PRESSURE. A QUASI-ZONAL PATTERN IS FAVORED ON LONG
RANGE DETERMINISTIC MODELS AND ENSEMBLES...WHICH WOULD FAVOR A
GRADUAL MODERATION TO NEAR NORMAL FOR THE FIRST DAY OF
METEOROLOGICAL WINTER ON SUNDAY.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* GUSTY SOUTHWEST WINDS TODAY.
* PERIODS OF LIGHT SNOW LIKELY BEGINNING ARND 17 UTC THROUGH MID
AFTERNOON...PERIODS OF MVFR TO IFR VIS AND MVFR CIGS POSSIBLE.
KREIN
//DISCUSSION...UPDATED 12Z...
THE MAIN FORECAST CONCERNS THIS MORNING CONTINUE TO REVOLVE AROUND
THE LIGHT SNOW EXPECTED ACROSS THE TERMINALS TODAY...ALONG WITH
THE STRONG SOUTHWESTERLY WINDS.
A STRONG PRESSURE GRADIENT IS SETTING UP ACROSS THE AREA EARLY THIS
MORNING IN ASSOCIATION WITH LOW PRESSURE ACROSS SOUTHERN ONTARIO AND
HIGH PRESSURE ACROSS THE SOUTHEASTERN CONUS. THIS WILL CONTINUE TO
SUPPORT GUSTY WINDS THROUGH THE DAY. OVERALL WINDS STILL APPEAR TO
BE SOUTHWESTERLY AROUND 15 TO 17 KT WITH GUSTS UP TO 25 TO 28 KT.
THE OTHER CONCERN IS THAT FOR LIGHT SNOW. SNOW IS BEGINNING TO FALL
ACROSS PORTIONS OF IOWA AND INTO NORTHWESTERN ILLINOIS THIS
MORNING. THIS ACTIVITY WILL TAKE SOME TIME TO MOVE ACROSS
NORTHEASTERN ILLINOIS AS THE LOWER LEVELS ARE STILL FAIRLY DRY.
HOWEVER...WITH TIME THIS MORNING THE LOWER LEVELS WILL MOISTEN TO
ALLOW SNOW TO START AFTER 16 UTC AT THE EASTERN TERMINALS AND A
COUPLE HOURS SOONER AT KRFD. OVERALL...THIS WILL NOT BE A BIG
SNOW MAKER. THERE WILL BE ABOUT A 4 TO 6 HOUR WINDOW FOR SOME
LIGHT SNOW. VISIBILITIES IN THE SNOW COULD DROP DOWN AROUND 2
MILES FOR A PERIOD AND SOME LIGHT ACCUMULATIONS UP TO A HALF INCH
ARE POSSIBLE...ESPECIALLY AT KRFD. THE SNOW CHANCES WILL END QUICKLY
BY MID TO LATE AFTERNOON AS DRYER AIR FILTERS IN ACROSS THE AREA.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* HIGH CONFIDENCE IN WINDS.
* MEDIUM TO HIGH CONFIDENCE IN PERIODS OF LIGHT SNOW WITH MVFR TO
IFR VIS AND MVFR CIGS.
* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...
TUESDAY NIGHT...FLURRIES IN THE EVENING WITH MVFR CIGS LIFTING TO
VFR.
WEDNESDAY...LAKE EFFECT MVFR CIGS PSBL.
THURSDAY AND FRIDAY...VFR.
SATURDAY...MVFR CIGS PSBL OVERNIGHT.
SUNDAY...MVFR CIGS PSBL
KJB
&&
.MARINE...
206 AM CST
A VERY ACTIVE WEATHER PATTERN WILL CONTINUE ACROSS THE GREAT LAKES
THROUGH MID WEEK. THE CURRENT GALE EVENT IS WELL UNDERWAY WITH
SEVERAL REPORTS OF 40+ KT WINDS...ESPECIALLY ACROSS THE NORTHERN
HALF OF THE LAKE. THESE GALES WILL CONTINUE THROUGH AT LEAST THE MID
AFTERNOON HOURS TODAY AS A AN AREA OF LOW PRESSURE TRACKS EASTWARD
ACROSS SOUTHERN ONTARIO. THE WINDS WILL GRADUALLY ABATE INTO THIS
EVENING. THE CURRENT GALE HEADLINE MAY BE ALOUD TO EXPIRE A FEW
HOURS EARLIER THAN THE CURRENT 9 PM DEADLINE. HOWEVER...AT THIS
POINT I WILL LEAVE THE HEADLINE TIMING ALONE.
THE NEXT ISSUE WILL BE LATER TUESDAY THROUGH MUCH OF WEDNESDAY. A
STRONG STORM SYSTEM IS EXPECTED TO MOVE UP THE EAST COAST DURING
THIS TIME...AND AS HIGH PRESSURE BUILDS IN ACROSS THE MISSOURI
VALLEY CONDITIONS WILL BECOME FAVORABLE FOR A PERIOD OF NORTHERLY
GALES UP TO 35 TO 40 KT. THIS LOOKS TO BE THE MOST PRONOUNCED ACROSS
SOUTHERN LAKE MICHIGAN...AND ANY LAKE EFFECT BANDS OF SNOW THAT
DEVELOP DURING THIS TIME COULD LEAD ALSO EVEN LEAD TO SOME LOCALLY
HIGH WINDS IN EXCESS OF 40 KT. IT APPEARS TO BE A GOOD BET THAT A
GALE HEADLINE WILL BE NEEDED DURING THIS TIME. I THREW AROUND THE
IDEA OF HOSTING A GALE WATCH FOR THIS PERIOD...BUT DUE TO THE FACT
IT IS STILL FAR ENOUGH OUT...I HAVE DECIDED TO LET THE CURRENT
GALE HEADLINES END PRIOR TO THE ISSUANCE OF A NEW HEADLINE.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 PM MONDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 9 PM MONDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
545 AM CST MON NOV 25 2013
.DISCUSSION...
323 AM CST
WITH NOVEMBER LOOKING TO FINISH WITH CONTINUED BELOW NORMAL
TEMPERATURES DURING ITS FINAL WEEK WITH LITTLE IN THE WAY OF SHARP
THERMAL CHANGES...THE PRIMARY FOCUS OF THE FORECAST WAS ON THE LIGHT
SNOW EVENT TODAY AND THEN THE LAKE EFFECT SNOW POTENTIAL INTO
NORTHWEST INDIANA TUESDAY NIGHT AND WEDNESDAY.
SOMEWHAT SPLIT UPPER FLOW IS IN PLACE ACROSS THE CENTRAL U.S. THIS
MONDAY WITH A QUICKLY-MOVING TROUGH ACROSS ONTARIO DIVING INTO THE
GREAT LAKES BY AFTERNOON...AND A CLOSED LOW ACROSS THE TEXAS
PANHANDLE BRINGING RARE NOVEMBER WINTER WEATHER HEADLINES TO THE
SOUTHERN PLAINS. OUR FORECAST AREA BASICALLY FALLS BETWEEN THESE TWO
SYSTEMS TODAY AND AS A RESULT THERE IS A VOID OF ANY OVERLY STRONG
FORCING OVERHEAD. ISENTROPIC ASCENT AND SATURATION WITHIN THE WSW
FLOW ALOFT THIS MORNING LOOKS TO BE THE PRIMARY CONTRIBUTOR TO
PRECIPITATION GENERATION...ALTHOUGH DRY LOW-LEVELS MAY KEEP IT
FLURRIES THROUGH MID TO LATE MORNING OVER CHICAGO. AN AXIS OF
FRONTOGENESIS CENTERED TO THE NORTHWEST OF THE AREA FROM EASTERN IA
INTO SOUTHERN WI THROUGH ~10 AM ON THE RAP AND LOCAL ARW MAY RESULT
IN BETTER SNOWFALL CLIPPING THE ROCKFORD AREA THIS MORNING...AND
CONCEIVABLY COULD SEE AN INCH BECAUSE OF THAT BUT THAT WOULD SEEM
THE MAXIMUM. AS THE SUBTLE FORCING AND MID-LEVEL SATURATION EVOLVES
EAST INTO THE AFTERNOON...PERIODS OF LIGHT SNOW WILL LIKELY RESULT
IN ONE HALF INCH OR LESS FOR MOST COMMUNITIES...AND NAMELY NORTH OF
I-80. WHILE NOT THE MOST IDEAL SYNOPTIC SETUP FOR FREEZING
DRIZZLE...THERE ARE SOME SIGNS ON GUIDANCE THAT AS ICE INTRODUCTION
IS LOST DURING THE MID TO LATE AFTERNOON THAT THERE MAY BE A BRIEF
WINDOW FOR THIS. ASCENT LOOKS WEAK AND CLOUD BASES LOOK HIGH FOR
THAT TO OCCUR THOUGH...SO CONTINUE TO NOT MENTION IN FORECAST.
THE AMOUNT OF CLOUD COVER TODAY WILL ONLY ALLOW TEMPERATURES TO RISE
BY ADVECTION...AND THAT WILL BE MEAGER AT THE SURFACE. SO MAINTAIN
HIGHS MAINLY IN THE LOWER 30S...WHICH WOULD RESULT IN THE THIRD
STRAIGHT DAY OF DOUBLE DIGIT DEPARTURES BELOW NORMAL.
A SECOND MORE ROBUST NORTHERN STREAM WAVE...THAT ACTUALLY LOOKS TO
BE A CLOSED SUB 520DM H5 LOW...WILL DROP INTO THE GREAT LAKES ON
TUESDAY. A FAIRLY DEEP PV ANOMALY IS SEEN WITH THIS ALONG WITH H5
TEMPS DOWN TO NEAR -30C...WHICH COME BARRELING INTO THE FORECAST
AREA BY LATE AFTERNOON INTO THE EVE TUESDAY ON THE GUIDANCE SUITE.
AN ASSOCIATED SURFACE COLD FRONT LOOKS TO STEEPEN LAPSE RATES AND
COULD SUPPORT SOME SNOW SHOWERS. CERTAINLY SOME FLURRIES LOOK TO BE
PRESENT INTO TUESDAY NIGHT. LOWS THAT NIGHT LOOK TO RETURN TO THE
MID AND POSSIBLY EVEN LOWER TEENS IN OUTLYING LOCATIONS.
MORE OF A CONCERN IS TURNING TO A POTENTIAL PLOWABLE SNOW FROM LAKE
EFFECT GENERATION INTO NORTHWEST INDIANA TUESDAY NIGHT INTO THE
BUSIEST TRAVEL DAY OF THE YEAR ON WEDNESDAY. THERE REMAINS MODEL
DIFFERENCES ON HOW QUICKLY THE AFOREMENTIONED SOUTHERN PLAINS UPPER
LOW AND THIS GREAT LAKES LOW PHASE. BUT OVERALL THE FLOW ACROSS LAKE
MI SHOULD BECOME STIFF AND NORTHERLY BY LATER TUESDAY NIGHT. THERE
ARE EVEN SIGNS ON SOME HIGH RESOLUTION MODELS...INCLUDING OUR LOCAL
ARW...OF MESO-LOW DEVELOPMENT TRANSLATING SOUTH ACROSS THE LAKE ON
TUESDAY NIGHT. CONFIDENCE ON SUCH A FEATURE IS LOW AT THIS
POINT...AS IS WHETHER THERE WILL EXIST A FOCUSED BAND OR JUST
WIDESPREAD SHOWERS OFF THE LAKE. BUT CONFIDENCE IS HIGH THERE WILL
BE AT LEAST SNOW SHOWERS INTO NORTHWEST INDIANA GIVE THE FORECAST
TRAJECTORIES...STEEP LOW-LEVEL LAPSE RATES...LAKE-INDUCED CAPE OF
AROUND 500 J/KG...AND EQUILIBRIUM LEVELS FORECAST AROUND 9000 FT.
THESE INDICES ACTUALLY INDICATE SOMEWHERE COULD GET A ROBUST SNOW
EVENT WITH HEAVY RATES WHICH WOULD IMPACT WEDNESDAY TRAVEL. IN
ADDITION...USING THE CIPS ANALOGS INDICATES A FAIRLY STRONG
CORRELATED EVENT FOR 850MB TEMPERATURES AND LOW-LEVEL WIND FLOW ON
11/21/08 AND THAT PRODUCED OVER 8 INCHES JUST EAST OF THE AREA. AT
THIS TIME HAVE CONTINUED THE TREND OF PREVIOUS SHIFT IN INCREASING
POPS ACROSS PORTER AND EASTERN LAKE COUNTIES.
BEYOND THERE WAS LITTLE CHANGE TO THE FORECAST AS THE HOLIDAY ITSELF
LOOKS QUIET ACROSS THE AREA WITH GRADUALLY BUILDING HEIGHTS AND
SURFACE HIGH PRESSURE. A QUASI-ZONAL PATTERN IS FAVORED ON LONG
RANGE DETERMINISTIC MODELS AND ENSEMBLES...WHICH WOULD FAVOR A
GRADUAL MODERATION TO NEAR NORMAL FOR THE FIRST DAY OF
METEOROLOGICAL WINTER ON SUNDAY.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 12Z...
* GUSTY SOUTHWEST WINDS TODAY.
* PERIODS OF LIGHT SNOW LIKELY AFTER 16-17 UTC THROUGH MID
AFTERNOON...PERIODS OF MVFR TO IFR VIS POSSIBLE.
KJB
//DISCUSSION...UPDATED 12Z...
THE MAIN FORECAST CONCERNS THIS MORNING CONTINUE TO REVOLVE AROUND
THE LIGHT SNOW EXPECTED ACROSS THE TERMINALS TODAY...ALONG WITH
THE STRONG SOUTHWESTERLY WINDS.
A STRONG PRESSURE GRADIENT IS SETTING UP ACROSS THE AREA EARLY THIS
MORNING IN ASSOCIATION WITH LOW PRESSURE ACROSS SOUTHERN ONTARIO AND
HIGH PRESSURE ACROSS THE SOUTHEASTERN CONUS. THIS WILL CONTINUE TO
SUPPORT GUSTY WINDS THROUGH THE DAY. OVERALL WINDS STILL APPEAR TO
BE SOUTHWESTERLY AROUND 15 TO 17 KT WITH GUSTS UP TO 25 TO 28 KT.
THE OTHER CONCERN IS THAT FOR LIGHT SNOW. SNOW IS BEGINNING TO FALL
ACROSS PORTIONS OF IOWA AND INTO NORTHWESTERN ILLINOIS THIS
MORNING. THIS ACTIVITY WILL TAKE SOME TIME TO MOVE ACROSS
NORTHEASTERN ILLINOIS AS THE LOWER LEVELS ARE STILL FAIRLY DRY.
HOWEVER...WITH TIME THIS MORNING THE LOWER LEVELS WILL MOISTEN TO
ALLOW SNOW TO START AFTER 16 UTC AT THE EASTERN TERMINALS AND A
COUPLE HOURS SOONER AT KRFD. OVERALL...THIS WILL NOT BE A BIG
SNOW MAKER. THERE WILL BE ABOUT A 4 TO 6 HOUR WINDOW FOR SOME
LIGHT SNOW. VISIBILITIES IN THE SNOW COULD DROP DOWN AROUND 2
MILES FOR A PERIOD AND SOME LIGHT ACCUMULATIONS UP TO A HALF INCH
ARE POSSIBLE...ESPECIALLY AT KRFD. THE SNOW CHANCES WILL END QUICKLY
BY MID TO LATE AFTERNOON AS DRYER AIR FILTERS IN ACROSS THE AREA.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 12Z...
* HIGH CONFIDENCE IN WINDS.
* MEDIUM-HIGH CONFIDENCE IN PERIODS OF LIGHT SNOW WITH MVFR TO IFR VIS.
* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
KJB
//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...
TUESDAY NIGHT...FLURRIES IN THE EVENING WITH MVFR CIGS LIFTING TO
VFR.
WEDNESDAY...LAKE EFFECT MVFR CIGS PSBL.
THURSDAY AND FRIDAY...VFR.
SATURDAY...MVFR CIGS PSBL OVERNIGHT.
SUNDAY...MVFR CIGS PSBL
KJB
&&
.MARINE...
206 AM CST
A VERY ACTIVE WEATHER PATTERN WILL CONTINUE ACROSS THE GREAT LAKES
THROUGH MID WEEK. THE CURRENT GALE EVENT IS WELL UNDERWAY WITH
SEVERAL REPORTS OF 40+ KT WINDS...ESPECIALLY ACROSS THE NORTHERN
HALF OF THE LAKE. THESE GALES WILL CONTINUE THROUGH AT LEAST THE MID
AFTERNOON HOURS TODAY AS A AN AREA OF LOW PRESSURE TRACKS EASTWARD
ACROSS SOUTHERN ONTARIO. THE WINDS WILL GRADUALLY ABATE INTO THIS
EVENING. THE CURRENT GALE HEADLINE MAY BE ALOUD TO EXPIRE A FEW
HOURS EARLIER THAN THE CURRENT 9 PM DEADLINE. HOWEVER...AT THIS
POINT I WILL LEAVE THE HEADLINE TIMING ALONE.
THE NEXT ISSUE WILL BE LATER TUESDAY THROUGH MUCH OF WEDNESDAY. A
STRONG STORM SYSTEM IS EXPECTED TO MOVE UP THE EAST COAST DURING
THIS TIME...AND AS HIGH PRESSURE BUILDS IN ACROSS THE MISSOURI
VALLEY CONDITIONS WILL BECOME FAVORABLE FOR A PERIOD OF NORTHERLY
GALES UP TO 35 TO 40 KT. THIS LOOKS TO BE THE MOST PRONOUNCED ACROSS
SOUTHERN LAKE MICHIGAN...AND ANY LAKE EFFECT BANDS OF SNOW THAT
DEVELOP DURING THIS TIME COULD LEAD ALSO EVEN LEAD TO SOME LOCALLY
HIGH WINDS IN EXCESS OF 40 KT. IT APPEARS TO BE A GOOD BET THAT A
GALE HEADLINE WILL BE NEEDED DURING THIS TIME. I THREW AROUND THE
IDEA OF HOSTING A GALE WATCH FOR THIS PERIOD...BUT DUE TO THE FACT
IT IS STILL FAR ENOUGH OUT...I HAVE DECIDED TO LET THE CURRENT
GALE HEADLINES END PRIOR TO THE ISSUANCE OF A NEW HEADLINE.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 PM MONDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 9 PM MONDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS GAYLORD MI
942 AM EST MON NOV 25 2013
.SYNOPSIS...
ISSUED AT 449 AM EST MON NOV 25 2013
WINTRY CONDITIONS WILL BE PREVALENT ACROSS NORTHERN MICHIGAN THROUGH
THE THANKSGIVING HOLIDAY WEEK...WITH SEVERAL WEAKER WEATHER SYSTEMS
DELIVERING REPEATED SHOTS OF BOTH SYSTEM AND LAKE EFFECT SNOW. THE
FIRST WILL ARRIVE THIS MORNING...AS LOW PRESSURE TRACKS NEAR JAMES
BAY...BRINGING A ROUND OF SNOW TO MUCH OF NORTHWEST LOWER AND
EASTERN UPPER. A COLD FRONT WILL GRADUALLY WORK THROUGH THE REGION
LATER TUESDAY...BRINGING RENEWED COLD CONDITIONS ALONG WITH MORE
LAKE EFFECT SNOW. THAT GENERAL TREND WILL CONTINUE INTO THANKSGIVING
DAY...BEFORE QUIET WEATHER MAKES A RETURN TOWARD NEXT WEEKEND.
&&
.UPDATE...
ISSUED AT 930 AM EST MON NOV 25 2013
QUICK SHOT OF LAKE ENHANCED SNOW CONTINUES TO IMPACT EAST UPPER
AND NW LOWER THIS MORNING...AS SHORT WAVE AND ASSOCIATED DEEP MOISTURE
SWINGS THROUGH THE REGION. OVERALL LAKE CONTRIBUTION NOT
GREAT...WITH WATER TEMPS NEAR +8C AND 850 MB TEMPS AROUND -6C
(IDEA FURTHER SUPPORTED BY 12Z APX/GRB SOUNDINGS).
THAT SAID...COMBINATION OF ONGOING SNOW BURST AND CONTINUED GUSTY
WINDS WILL STILL RESULT IN NEAR-ADVISORY CONDITIONS NEXT SEVERAL
HOURS WITH LOCALLY DIFFICULT TRAVEL. HOWEVER...AS DEEPER MOISTURE
DEPARTS AND ONLY MARGINAL LAKE CONTRIBUTIONS LINGER...SUSPECT A
MARKED DECREASE IN SNOW SHOWER INTENSITY EARLY THIS AFTERNOON. FOR
THIS REASON...EXPECT 2-4 INCH SNOW AMOUNTS /MAINLY NW LOWER/ TO
HOLD FOR THE DAY.
UPDATE ISSUED AT 629 AM EST MON NOV 25 2013
DEEP MOISTURE OUT AHEAD OF AN ADVANCING COLD FRONT IS STARTING TO
DEVELOP SNOWS ACROSS FAR NRN LAKE MICHIGAN AND THROUGH THE STRAITS
REGION. STILL DEFINITELY EXPECTING A RAPID PRODUCTION AND
INTENSIFICATION OF SNOWS IN A SW TO NE ORIENTED BAND...COMBINED
WITH VERY STRONG SW WIND GUSTS TO 50 MPH. THIS WILL BRING A PERIOD
OF MODERATE TO HEAVY SNOWS ACROSS MUCH OF NW LOWER AND EASTERN
SECTIONS OF CHIP/MACK COUNTIES THIS MORNING. ALREADY ISSUED THE
INITIAL SPS ALERTING OF RAPIDLY DEVELOPING HAZARDOUS DRIVING
CONDITIONS. FOLKS...PLEASE ALLOW EXTRA TIME TO REACH YOUR
DESTINATION. DID INCREASE SNOWFALL ACROSS AN AREAS SURROUNDING
LEELANAU COUNTY...WHERE A LONGER PERIOD OF SNOWS ARE EXPECTED THIS
MORNING. OTHERWISE...THE FORECAST IS IN GOOD SHAPE.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 449 AM EST MON NOV 25 2013
WELL...THAT WAS A NICE 12-ISH HOUR RESPITE FROM THE ACTIVE WEATHER.
NOW IT`S GAME ON ONCE AGAIN...WITH THE MAIN FORECAST ISSUES BEING OF
THE LAKE EFFECT/ENHANCEMENT VARIETY...ALONG WITH WIND ISSUES THROUGH
THE DAY TODAY. EARLY MORNING ANALYSIS PLACES VERY WEAK SHORTWAVE
RIDGE AXIS JUST TO THE EAST OF NORTHERN MICHIGAN...WITH DEEP AND
QUITE STRONG SOUTHWESTERLY FLOW WELL RAMPED UP ACROSS THE NORTHERN
LAKES IN ADVANCE OF ANOTHER STRONG UPPER WAVE QUICKLY AMPLIFYING
THROUGH SOUTHERN MANITOBA. INITIAL PUSH OF THAT WARM ADVECTION
EARLIER LED TO A BRIEF AXIS OF LIGHT SNOW MARCHING THROUGH
NORTHERN/EASTERN AREAS...WITH SECONDARY SURGE OF MUCH DEEPER AND
STRONGER ASCENT GOING INTO GRADUAL TOP-DOWN SATURATION OFF TO OUR
WEST AT THE MOMENT...AS EVIDENCED BY CEILINGS FALLING 5-8KFT OVER
THE PAST FEW HOURS. MEANWHILE...QUITE THE WINDY CONDITIONS HAVE
SHOWN UP RECENTLY AS CORE OF RATHER IMPRESSIVE 45-55 KNOT FLOW IS
ROLLING OVERHEAD...COMBINING WITH A REMNANT UNSTABLE AIRMASS ACROSS
THE LAKES TO PRODUCE SOME RATHER BEEFY WIND GUSTS PUSHING 50 MPH
ALONG THE LAKE MICHIGAN SHORE.
THE ABOVE MENTIONED WARM ADVECTION WILL BE IMPORTANT FOR OUR AREA
THIS MORNING...AS THE ADDED MOISTURE (FROM AN INITIALLY QUITE DRY
AIRMASS) GIVES A BIG BOOST OVER LAKE MICHIGAN. ALREADY SEEING THE
FIRST HINTS OF THIS RIGHT NOW...BUT THE THOUGHT IS THAT DEEPER
MOISTURE OVERRIDING THE LAKE WILL GO INTO THE RAPID PRODUCTION OF A
SOUTHWEST FLOW LAKE BAND THE NEXT FEW HOURS...WHICH WILL ULTIMATELY
GET PUNTED ONSHORE AS THE SHARP UPPER WAVE OVER MANITOBA WORKS
TOWARD OUR AREA. THESE TYPES OF SETUPS ALWAYS HAVE TROUBLE WRITTEN
ALL OVER THEM FROM AN IMPACT STANDPOINT...AS THERE SHOULD BE A
COUPLE HOUR WINDOW FOR SOME HEAVY SNOW TO FALL UP AND DOWN THE LAKE
MICHIGAN SHORELINE COUNTIES...AND PROBABLY EVEN FARTHER INLAND INTO
THE HIGHER TERRAIN WHERE UPSLOPE TYPICALLY WORKS ITS MAGIC IN SUCH A
SETUP. GIVEN WARMING THERMAL PROFILES...SNOW TO LIQUID RATIOS SHOULD
BE RATHER LOW...AS EVIDENCED BY A QUITE DEEP ISOTHERMAL LAYER AROUND
-6C PER FORECAST RAOBS...MAKING FOR MORE OF A GREASY/SLIPPERY SNOW.
THROW IN SOME QUITE GUSTY WINDS AND THE STAGE IS PROBABLY SET FOR A
PERIOD OF SLOPPY TRAVEL/LOW VSBYS ACROSS PRIMARILY NORTHWEST
LOWER...WITH A QUICK 2-3" OF SNOW EXPECTED TO FALL. LOCAL 4/12KM APX
WRF AND RECENT HRRR RUNS ARE EVEN MORE IMPRESSIVE...PAINTING AN AXIS
OF 0.4" OF LIQUID UP TOWARD CHARLEVOIX/EMMET/CHEBOYGAN/OTSEGO/ANTRIM
COUNTIES...WITH A SECONDARY MAXIMUM NEAR CADILLAC. GIVEN THE
EXPECTED LOWER RATIOS...SHOULDN`T SEE ACCUMULATION GET OUT OF
HAND...EVEN IF THE HIGHER QPF FORECASTS VERIFY. NOT SURE THIS WILL
BE WORTHY OF A WINTER WEATHER HEADLINE - PROBABLY MORE LIKE AN
SPS...ESPECIALLY CONSIDERING THE WORST CONDITIONS SHOULD OCCUR JUST
AFTER THE MORNING COMMUTE (MAINLY 9AM-1PM).
WINDS WILL SUBSIDE HEADING INTO THE AFTERNOON AS THE CORE OF
STRONGEST 950-900MB FLOW EXITS EAST...ALL WHILE DEEPER MOISTURE ALSO
STRIPS OUT. THAT LEAVES US IN MORE OF A LIGHT SNOW SHOWERS/SNIZZLE
REGIME FOR MUCH OF THE AFTERNOON AS SOUTHWEST FLOW CONTINUES BUT
WHILE CLOUD TOP TEMPS HOVER ONLY AROUND -8C. PROBABLY NOT LOOKING AT
MUCH ADDITIONAL ACCUMULATION FOR MOST AREAS THROUGH LATE AFTERNOON.
HOWEVER...MORE ISSUES SHOW UP BY EARLY EVENING WITH PERSISTENT HINTS
OF A STRONGER FRONTAL SNOW BAND BEING BROUGHT ASHORE INTO EASTERN
UPPER AS LOW PRESSURE NEARS THE SOUTHERN TIP OF JAMES BAY AND SWINGS
A COLD FRONT THROUGH THE EASTERN U.P. THAT FEATURE WILL IN ALL
LIKELIHOOD BECOME ABSORBED INTO THE LAKE AGGREGATE TROUGH OVER
EASTERN LAKE SUPERIOR...WITH PERHAPS EVEN A WEAK CIRCULATION CENTER
DEVELOPING IN RESPONSE TO YET ANOTHER STRONG UPPER WAVE ENTERING THE
ARROWHEAD OF MINNESOTA. THAT SETUP COULD LEAD TO ALL KINDS OF
MESOSCALE GARBAGE...BUT THE CLEAR SIGNAL IS FOR AN ENHANCED
CONVERGENCE BAND TO SKIRT FAR NORTHERN CHIPPEWA COUNTY...MAINLY
TOWARD PARADISE/WHITEFISH POINT...WITH MAYBE A COUPLE INCHES
POSSIBLE. FARTHER SOUTH...LOOKING LIKE PERSISTENT MORE NEBULOUS SNOW
SHOWERS WILL CONTINUE OVERNIGHT FOR SOUTHWEST FLOW AREAS ACROSS
NORTHWEST LOWER UP TOWARD DRUMMOND ISLAND. WAS A LITTLE CONCERNED
ABOUT SOME DRIZZLE POSSIBILITIES GIVEN INITIALLY SHALLOW NATURE OF
MOISTURE...BUT GRADUAL INTRUSION OF COLDER AIR ALOFT SHOULD FAVOR
ICE IN THE CLOUDS AS CLOUD TOP TEMPS END UP AROUND -12C BY 06Z. NO
MAJOR ACCUMULATION FORESEEN FOR NORTHERN LOWER OVERNIGHT.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 449 AM EST MON NOV 25 2013
A VERY ACTIVE AND RAPIDLY CHANGING WEATHER PATTERN WILL REMAIN
LOCKED IN ACROSS THE GREAT LAKES THROUGH THE THANKSGIVING HOLIDAY
WITH A SERIES OF SHORTWAVES AND SHOTS OF COLDER CANADIAN AIR
RESULTING IN A COUPLE OF ROUNDS OF LAKE EFFECT AND LAKE ENHANCED
SNOWFALL. THIS WILL ALSO PREVENT US FROM ANY SIGNIFICANT WARMING FOR
THE NEXT SEVERAL DAYS. A FAIRLY QUIET PERIOD OF WEATHER IS THEN
ANTICIPATED FOR FRIDAY THROUGH THE WEEKEND.
TUESDAY THROUGH WEDNESDAY NIGHT...A SIMILAR SET UP LIKE TODAY...IS
EXPECTED FOR TUESDAY WITH NEXT VIGOROUS SHORTWAVE...COLD FRONT AND
DEEPER MOISTURE ANTICIPATED TO MOVE IN ACROSS NRN MICHIGAN. THIS
TIME AROUND...WE WILL HAVE A BIT DEEPER INSTABILITY BUT LESS WIND.
WEST/WSW FLOW AHEAD OF THIS FRONT...H8 TEMPS COLDER IN THE -10C TO
-11C RANGE AND INVERSION HEIGHTS TO 7KFT WILL INCREASE TO NEAR 9KFT
WITH COLD ADVECTION THROUGH THE DAY...BUT A DRAMATIC SHIFT IN WINDS
TO OUT OF THE NNW INTO TUESDAY EVENING. MOISTURE IN THE LOWEST
LEVELS ARE STARTING TO LOOK A BIT MORE MOISTURE...MORE SO ON THIS
RUN OF THE BUFR SOUNDINGS. THE MOST IMPRESSIVE LES PARAMETERS ARE
REALLY FOCUSED TUESDAY EVENING AFTER THE FLOW TURNS NORTHERLY WITH
DEEPEST INSTABILITY WITH PASSAGE OF UPPER TROUGH AXIS/COLD AIR
ALOFT. THIS WILL FOCUS THE BEST ACCUMULATION POTENTIAL ACROSS THE
GTV BAY REGION AND AREAS SOUTH...WHERE ALSO...GUSTY WINDS COULD
LEAD TO BLOWING AND DRIFTING ISSUES. A CONSERVATIVE 3-6 INCHES OF
SNOW WILL BE POSSIBLE IN THIS REGION TUESDAY-TUESDAY NIGHT...LEADING
TO THE MOST HAZARDOUS DRIVING CONDITIONS EXPECTED IN THE LONG TERM
PORTION OF THE FORECAST. THE AIR MASS DRIES WITH LOWERING INVERSION
HEIGHTS INTO WEDNESDAY...HOWEVER CONTINUED COLD ADVECTION AND BEST
FETCH INTO GTV BAY WILL LEAD TO ANOTHER 1-2 INCHES OF SNOW
THERE...WHILE AMOUNTS ARE LESS IMPRESSIVE ELSEWHERE. FAR NE LOWER
NEAR ROGERS CITY/ALPENA AND OSCODA WILL SEE A SMATTERING OF 1 TO
MAYBE 3 INCH LOCAL AMOUNTS TUESDAY NIGHT INTO WEDNESDAY. WEDNESDAY
NIGHT...INVADING HIGHER PRESSURE AND LIGHTER WINDS FOR A LESSER
THREAT TO ANYTHING SIGNIFICANT IN THE SNOW DEPARTMENT.
HOWEVER...WILL HAVE TO KEEP AN EYE ON NEXT INCOMING SHORTWAVE AND
WARM ADVECTION OVER THE TOP OF THE REMAINING INSTABILITY...ALTHOUGH
MOST AREAS...LOOK TO HAVE A DISCONNECT FROM THE MOISTURE AND
ENHANCEMENT SEEDED FROM ALOFT. SLOWLY BACKING LOW LEVEL WINDS WILL
FOCUS ANY EMERGING THREAT OF RENEWED SNOW IN AND AROUND LAKE
MICHIGAN.
THANKSGIVING DAY AND NIGHT...THIS INCOMING WAVE IS RATHER WEAK
COMPARED TO IT`S PREDECESSORS....ALTHOUGH THE WARM ADVECTION/SEEDING
ALOFT DOES LOOK TO STILL HAVE SOME SORT OF ENHANCEMENT TO THE LAKE
EFFECT THROUGH THE HOLIDAY AND THURSDAY NIGHT. WINDS ARE EXPECTED TO
BE FAIRLY LIGHT...AND NOW SHIFTING ALL AROUND TO THE SW AS THIS
ENHANCEMENT PROCESS IN UNDERWAY...SPREADING SNOWS AROUND LAKE
MICHIGAN WITH LESS INLAND PENETRATION. THESE FINER DETAILS WILL
REALLY HAVE TO BE EXAMINED FURTHER OVER THE NEXT COUPLE OF DAYS TO
PROVIDE A MORE DETAILED HOLIDAY FORECAST. WIND DIRECTIONS AND SPEEDS
BEING THE MOST CRUCIAL...WHICH HAS A BIT OF UNCERTAINTY.
FRIDAY THROUGH SUNDAY...THIS WEAKER WAVE EXITS FRIDAY WITH SHALLOW
MID LEVEL RIDGING...AHEAD OF NEXT ADVERTISED SHORTWAVE ARRIVING
SATURDAY. A WEAK COLD FRONT LAYS ACROSS/WASHES OUT OVER NRN
MICHIGAN. COULD BE ONE LAST HOORAH OF SOME WEAKER LAKE EFFECT...BUT
THIS APPEARS TO BE THE LEAST OF CONCERN IN THE SERIES OF LAKE EFFECT
EVENTS. THIS MAINLY DUE TO THE CONTINUED LOW LEVEL WARM ADVECTION
AND GRADUAL EROSION OF THE OVERLAKE INSTABILITY. WILL HAVE RATHER
SMALL CHANCES FOR SNOW IN AND AROUND LAKE MICHIGAN IN THE SW FLOW
THAT PERSISTS INTO SUNDAY. TEMPERATURES WILL MODERATE BACK INTO THE
LOWER HALF OF THE 30S OVER THE WEEKEND.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 629 AM EST MON NOV 25 2013
HIGH LEVEL OF CONCERN THIS MORNING FOR THE AVIATION COMMUNITY. A
BAND OF MODERATE TO HEAVY SNOWFALL WILL ENTER INTO THE NW LOWER
AIRPORTS STARTING WITH PLN AT THE START OF THE TAF PERIOD...AND
REACHING TVC/MBL A FEW HOURS LATER. THIS BAND OF SNOW WILL RAPIDLY
INTENSIFY AND INCREASE IN COVERAGE THIS MORNING...AND COMBINE WITH
VERY STRONG WIND GUSTS OUT OF THE SW...MAXING OUT AT 40-50
MPH...ESPECIALLY AT MBL. THESE WINDS HAVE ALREADY SUBSTANTIALLY
MIXED DOWN TO THE SFC...AND THIS MECHANICAL MIXING IS STRONG
ENOUGH TO ELIMINATE ALL MENTION OF LLWS...BUT IT`S STILL BLOWING
VERY HARD ALOFT. WILL BRING IN A PERIOD OF IFR AT ALL AIRPORTS
EXCEPT APN...WHICH WILL LIKELY JUST SEE SOME MVFR CONDITION LATER
THIS MORNING/MIDDAY.
LAKE EFFECT SNOWS WILL CONTINUE THROUGH THE DAY AND NIGHT IN
DEVELOPING MORE WESTERLY FLOW...WHICH DOES DECREASE THROUGH
THE LATTER HALF OF THE DAY AN NIGHT. THIS PRIMARILY AFFECTS PLN
WHERE MVFR CONDITIONS WILL BE THE RULE. PERIODS OF MVFR CIGS/VSBYS
FOR TVC...TO A LESSER DEGREE AT MBL. SNOWS NOT GOING TO REACH APN.
A QUICK 1-3 INCHES OF SNOW IS DEFINITELY POSSIBLE THIS MORNING
WITH LIQUID TO SNOW RATIOS ON THE LOW END AT AROUND 10:1.
OVERALL CONFIDENCE IS HIGH FOR THE EVOLUTION OF THE DESCRIBED
WEATHER.
&&
.MARINE...
ISSUED AT 449 AM EST MON NOV 25 2013
A WINDY ONE OUT THERE TO START...WITH GALES FOR MOST OF THE WATERS.
THOSE WINDS WILL SUBSIDE LATER THIS AFTERNOON AND ESPECIALLY THIS
EVENING...THOUGH WILL REMAIN A BIT GUSTY IN THE 20-25 KNOT RANGE AS
IS TYPICAL FOR LATE NOVEMBER. WINDS WILL GRADUALLY COME AROUND TO
THE NORTHWEST ON TUESDAY AND THEN NORTH TUESDAY NIGHT AND
WEDNESDAY...WITH CONTINUED GUSTS OF 25-30 KNOTS EXPECTED. COULD SEE
A PERIOD OF GALES ON MAINLY LAKE MICHIGAN SOMETIME TUESDAY NIGHT...
BUT CONFIDENCE IN THAT IS LOW AT THIS TIME. HIGH PRESSURE WILL
FINALLY WIN THE BATTLE BY THURSDAY...WITH A RETURN TO A BRIEF PERIOD
OF MUCH LIGHTER WINDS OF THE 15 KNOTS OF LESS VARIETY.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...WIND ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR MIZ015-016-019-
020-025-031.
LH...GALE WARNING UNTIL 10 PM EST THIS EVENING FOR LHZ345>349.
LM...GALE WARNING UNTIL 10 PM EST THIS EVENING FOR LMZ323-341-342-
344>346.
LS...SMALL CRAFT ADVISORY UNTIL 10 PM EST THIS EVENING FOR LSZ321-322.
&&
$$
UPDATE...BS
SYNOPSIS...DL
SHORT TERM...DL
LONG TERM...SD
AVIATION...SD
MARINE...DL
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
645 AM EST MON NOV 25 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 516 AM EST MON NOV 25 2013
WV IMAGERY AND RUC ANALYSIS INDICATED WNW MID/UPPER LEVEL FLOW FROM
CNTRL CANADA THROUGH THE GREAT LAKES WITH ONE SHORTWAVE TROUGH FROM
NW ONTARIO INTO NW MN AND ANOTHER WELL TO THE NORTH MOVING INTO NRN
SASK. AT THE SFC...A TIGHT PRES GRADIENT PREVAILED ACROSS THE WRN
GREAT LAKES BTWN A 1000 MB LOW LOCATED JUST NORTH OF THUNDER BAY
ONTARIO AND A 1036 MB RIDGE OVER THE OH VALLEY. WITH THE STRONGEST
PRES FALLS MOVING TO THE NE OF LAKE SUPERIOR...VERY STRONG SW WINDS
PERSISTED ACROSS WRN LAKE SUPERIOR AND NRN LAKE MICHIGAN. WAA
LEADING TO INCREASING STABILITY HAS LIMITED MIXING OF 45-50 KNOT
925-850 MB WINDS TOWARD THE SFC EXCEPT OVER THE RELATIVELY WARM LAKE
MICHIGAN WATERS. GUSTS IN THE 35-40 KT RANGE PERSISTED FROM FAIRPORT
TO PORT INLAND WHERE A WIND ADVISORY WAS IN EFFECT. WINDS OVER
INLAND LOCATIONS AT ESC AND ISQ WERE ONLY GUSTING TO AROUND 25
KNOTS. RADAR INDICATED WEAK RETURNS...MAINLY OVER THE ERN CWA...WITH
SOME PATCHY LIGHT SNOW OR FLURRIES SUPPORTED BY 700-300 QVECTOR CONV
AND ISENTROPIC LIFT AHEAD OF THE UPSTREAM SHRTWV.
TODAY...EXPECT WINDS TO SUBSIDE BY THE 15Z WIND ADVISORY EXPIRATION
TIME AS THE CORE OF THE STRONGEST 925-850 MB WINDS SHIFTS OFF TO THE
EAST. AS THE AREA OF LIGHT SNOW MOVES TO THE EAST...SOME LAKE
ENHANCEMENT MAY BE POSSIBLE WITH THE SW FLOW OFF OF LAKE MICHIGAN
BUT SHOULD REMAIN MAINLY TO THE SOUTH AND EAST OF THE CWA. OVER THE
KEWEENAW...AN AREA OF LOW LEVEL CONV AS WINDS VEER FROM SW TO W MAY
BRING A BRIEF PERIOD OF LAKE ENHANCED SNOW. HOWEVER...MID LEVEL
DRYING WITH THE DRY SLOT AND MARGINAL INSTABILITY WITH 850 MB TEMPS
AROUND -7C (LAKE SFC NEAR 4C) SUPPORTS ONLY CHANCE POPS WITH ANY
ACCUMULATIONS ONLY AMOUNTING TO A HALF INCH OR LESS. INCREASING
850-700 MB MOISTURE AND AND 850/700 MB TEMPS DROPPING TO -10C/-17C
WITH THE APPROACH OF THE SHRTWV WILL ALSO BRING AN INCREASE IN LAKE
ENHANCED SNOW INTO THE WEST AND THE ERN SHORELINE FROM PICTURED
ROCKS TO GRAND MARAIS.
TONIGHT...STRONGER CAA DROPPING 850 MB TEMPS TO AROUND -18C BOOSTING
LAKE INDUCED CAPES TO NEAR 700 J/KG ALONG WITH STRENGTHENING
CYCLONIC NW FLOW WILL BRING A FURTHER INCREASE IN LES INTO THE WEST.
THE HIGH RES MODELS OFFER A VARIETY OF SOLUTIONS AS TO WHERE THE
HEAVIER SNOW BANDS WILL FOCUS AND DELAY THE STRONGER VEERING WIND
SHIFT AND LOW LEVEL CONV BAND MOVING IN TIL AFT 12Z. ALTHOUGH
SEVERAL INDICATE THE GREATER SNOW POTENTIAL INTO THE KEWEENAW AND
IRONWOOD AREAS...CONFIDENCE IN IN HIGHLIGHTING ANY PARTICULAR
LOCATION IS LIMITED. SO...A GENERAL 2 TO 5 INCH FCST WAS INCLUDED
FOR MOST OF THE NW TO WNW FLOW SNOWBELTS IN THE WEST AS WELL AS
LOCATIONS NORTH OF M-28 EAST OF MUNISING.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 437 AM EST MON NOV 25 2013
EXTENT OF LAKE EFFECT SNOW AND SNOW AMOUNTS ALONG WITH THE NEED FOR
ANY ADVISORIES OR WARNINGS TUESDAY/TUESDAY NIGHT IS PRIMARY FOCUS.
IN LARGE SCALE...STRONG SHORTWAVE IN NORTHERN STREAM CURRENTLY OVER
NORTHERN MANTIOBA WILL BE CROSSING UPR MICHIGAN AND LK SUPERIOR ON
TUESDAY. NAM/GFS/ECMWF DECENT AGREEMENT WITH TIMING OF LARGER SCALE
IMPACTS AS THEY ALL SHOW H7-H5/H5-H3 Q-VECTOR CONVERGENCE INTO WESTERN
UPR MICHIGAN BEFORE 12Z TUESDAY SPREADING TO CNTRL CWA BY 18Z AND
EXITING EASTERN CWA BY 00Z WEDNESDAY. MAY SEE MINOR LGT SNOW EVEN
INTO SOUTH AS THE SHORTWAVE CROSSES THE REGION. BIGGEST IMPACT
THOUGH WILL BE ON LK EFFECT THAT BEGINS LATE TONIGHT. NAM AND GFS
FORECAST SOUNDINGS SHOW GOOD RESPONSE FM THE WAVE WITH INVERSION
HEIGHTS RISING ABOVE 5KFT LATE TONIGHT AND SPIKING UP TO 8-10KFT BY
MIDDAY TUESDAY. LAKE EQUILIBRIUM LEVELS INCREASE TO 13KFT AND LAKE
INDUCED CAPE VALUES CLIMB OVER 700J/KG AS H85 TEMPS FALL TO -17C TO
-20C BY TUESDAY NIGHT. SOUNDINGS ALSO INDICATE INCREASING MOISTURE
QUALITY TUESDAY INTO MOST OF TUESDAY NIGHT. SO...INSTABILITY AND
MOISTURE NOT THE ISSUE FOR MODERATE TO HEAVY SNOW. BOTH PARAMETERS
ARE THERE NO DOUBT. MAIN STICKING POINT FOR THE FORECAST ARE
LOW-LEVEL WIND FIELDS AND MORE SPECIFICALLY THE WIND DIRECTION WHICH
IS ALL SO CRITICAL FOR PEGGING WHERE HEAVIEST LK EFFECT WILL OCCUR.
UNFORTUNATELY...NOTEABLE DIFFERENCES EXIST BTWN THE NAM/NCEP HIGH
RES RUNS AND THE COARSER ECMWF/GFS AND ALSO THE GEM. MAIN ISSUE IS
HOW QUICKLY SOUTH TO BRING LOW-LEVEL WIND SHIFT PASSAGE ON TUESDAY.
PASSAGE OF THE TROUGH ESSENTIALLY KICKS LK EFFECT FM WNW/NW FLOW
AREAS TO AREAS FAVORED BY N/NNE WINDS. USUALLY LIKE THE NAM WITH
HIGHER RESOLUTION DETAILS...BUT SUCH A QUICK TROUGH PASSAGE AT
15Z-18Z ON TUESDAY IN THE NORTH SEEMS QUESTIONABLE AS SHORTWAVE
TROUGH AXIS IS STILL OVER CNTRL UPR MICHIGAN AT 18Z. WOULD EXPECT
THE TROUGH PASSAGE TO OCCUR TUESDAY EVENING IN THE WAKE OF THE
SHORTWAVE TROUGH CROSSING THE AREA. OVERALL...PREFERRED SOLUTION
IS PROBABLY MOST CLOSEST TO GFS/LOCAL REGIONAL WRF AND ECMWF.
WHAT THIS MEANS IN TERMS OF LK EFFECT SNOW IS EXPECT A PROLONGED
PERIOD OF LK EFFECT FOR WNW/NW FLOW AREAS LATE TONIGHT THROUGH LATE
TUESDAY AFTN /WHITE PINE TO ROCKLAND/TWIN LAKES AND MAYBE AS FAR
NORTH AS HOUGHTON/ AND ALSO OVER NORTHERN PARTS OF ALGER AND LUCE
COUNTIES. HEAVIER LK EFFECT THEN SHIFTS TO GOGEBIC/WESTERN ONTONAGON
AND MARQUETTE COUNTIES BY TUESDAY EVENING. BASED ON EXPECTED SLR/S
NEARING 20:1 OR EVEN ABOVE 20:1 AND QPF WHICH WAS BLEND OF REGIONAL
WRF AND EVENTUALLY THE WETTER NAM DNG LATER TUESDAY...SEEMS LIKE A
SOLID ADVY EVENT IS IN STORE WITH SNOW AMOUNTS OF 4-6/5-8 INCHES IN
THE 12 HOUR PERIOD FOR TUESDAY AND AGAIN ON TUESDAY NIGHT...THOUGH
THE LOCATIONS OF HEAVIEST SNOW SHOULD SHIFT AROUND AS WINDS IN THE
LAKE CONVECTIVE LAYER SO SOME SHEAR AND DO NOT STAY LOCKED IN THE
SAME DIRECTION FOR VERY LONG PERIOD OF TIME. SOME LOCATIONS IN THE
FAR WESTERN CWA /VCNTY OF IWD TO BERGLAND AND WHITE PINE/ MAY COME
CLOSER TO WARNING CRITERIA TUESDAY AFTN INTO TUESDAY NIGHT BUT SINCE
THE LARGER SCALE FORCING IS DIMINISHING WHEN WIND DIRECTION BECOMES
A MORE FAVORABLE N-NNE TO INCREASE CONVERGENCE IN THESE AREAS...WILL
OPT TO ISSUE THE ADVY AND LET FUTURE SHIFTS UPGRADE TO WARNING IF IT
IS NEEDED. SNOW WILL BE THE MAIN ISSUE WITH THIS EVENT. WINDS WILL
BE GUSTY 25-35 MPH...BUT STRONGEST WINDS AND BLSN/VSBY IMPACTS WILL
BE MORE OVER THE NORTHERN PARTS OF THE KEWEENAW ON TUESDAY AND
PERHAPS INTO NCNTRL UPR MICHIGAN ON TUESDAY NIGHT. NOT EXPECTING
WIDESPREAD BLSN AS THE EVENT THIS LAST WEEKEND HAD.
FOR NOW...COORDINATED WITH SHORT TERM FORECASTER AND PUT OUT LAKE
EFFECT SNOW ADVISORIES FOR WESTERN TIER. ADDITIONAL HEADLINES WILL
LIKELY BE ISSUED OVER NCNTRL AND POSSIBLY NORTHEAST CWA LATER TODAY
OR TONIGHT...BUT SINCE THE MORE SIGNIFICANT SNOW WILL NOT OCCUR IN
THESE AREAS UNTIL LATER TUESDAY OR EVEN AS LATE AS TUESDAY NIGHT IF
GFS IS COMPLETELY CORRECT...WILL NOT ISSUE THOSE HEADLINES NOW. NOT
ENOUGH CONFIDENCE THAT THESE AREAS WOULD SEE WARNING AMOUNTS SO DID
NOT WANT TO PUT A WATCH OUT EITHER.
SNOW SHOWERS PERSIST FOR N FLOW AREAS ON WEDNESDAY...BUT INTENSITY
WILL BE ON THE WANE WITH LOWERING INVERSION HEIGHTS TO AT OR BLO
5KFT. EVEN AS SNOW DIMINISHES...THE DGZ WILL BE IN THE HEART OF THE
LAKE CONVECTIVE LAYER SO WHAT SNOW SHOWERS ARE LEFTOVER ON WEDNESDAY
WILL BE THE EFFECIENT FLUFFY TYPE. WINDS WILL BE ON THE DECREASE AS
WELL...AS WILL BLSN/ASSOCIATED VSBY ISSUES. SINCE THE FLOW REMAINS
LGT NORTH ALL DAY AND INSTABILITY IS MORE THAN SUFFICIENT...SNOW
SHOWERS PROBABLY WILL NOT END COMPLETELY FOR FAR WEST OR NCNTRL BUT
THEY MAY BECOME PINNED CLOSER TO THE SHORELINES ON WEDNESDAY NIGHT
AS MESOSCALE EFFECTS/LAND BREEZES START TO DRIVE THE LOW-LEVEL
CONVERGENCE.
STILL COULD SEE SOME LGT SNOW ON THANKSGIVING. NO BIG IMPACT TO
TRAVEL EXPECTED THOUGH. BEST CHANCE OVER THE NORTHERN TIER. WEAK
TROUGH WORKS THROUGH THURSDAY NIGHT INTO FRIDAY. COULD SEE SOME SNOW
SHOWERS ACROSS KEWEENAW IN WNW FLOW ON FRIDAY. WEEKEND WILL FEATURE
MODEST WARMING TREND WITH SOME AREAS SLIGHTLY ABOVE FREEZING FOR
DAYTIME HIGHS. LGT SNOW MAY ACCOMPANY THIS WARM AIR ADVECTION BUT
LOOKS LIKE BETTER CHANCE FOR ANY SNOW ACCUMULATION WILL REMAIN TO
NORTH OF CWA.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 645 AM EST MON NOV 25 2013
AS A STRONG DISTURBANCE OVER NW ONTARIO AND ITS ATTENDANT SFC COLD
FRONT DIGS SE INTO THE NRN GREAT LAKES...EXPECT MVFR CIGS TO
DEVELOP OVER THE W AT IWD AND CMX THIS MORNING. WITH A STRONG
UPSLOPE W WIND...THE FROPA WILL ALSO BRING MVFR VSBY FOR A COUPLE
HOURS AT CMX THIS MORNING. ALTHOUGH SOME MVFR CIGS MAY OCCUR AT SAW
WITH THE FROPA...DOWNSLOPE NATURE OF THE FLOW INDICATES THIS
CONDITION WL BE MARGINAL AND MAY REMAIN VFR. THE BEST CHANCE OF MORE
PERSISTENT MVFR WX WILL BE AT CMX WITH A MORE PRONOUNCED UPSLOPE W
WIND...WHICH WILL GUST AS HIGH AS 30 KTS WITH A SLOW INFLUX
OF COLDER AIR/MORE DESTABILIZATION. THE APPROACH OF ANOTHER
DISTURBANCE AND LOW PRES TROF MAY BRING ANOTHER ROUND OF HEAVIER
LES TO CMX THIS EVENING...SO FCST IFR VSBYS AT THIS SITE THEN.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 533 AM EST MON NOV 25 2013
SW TO W GALES OVER LAKE SUPERIOR THIS MORNING ARE EXPECTED TO
DIMINISH BY LATE MORNING OVER THE WEST AND MID AFTERNOON OVER THE
EAST. THE PRES GRADIENT WILL WEAKEN AS A TROUGH MOVES THROUGH THE
LAKE AND LOW PRESSURE NORTH OF LAKE SUPERIOR MOVES TOWARD JAMES BAY.
NORTHWEST WINDS TO 25 KTS SHIFT TO THE NORTH TO 30 KTS LATER TUESDAY
AND TUESDAY NIGHT. MAY GET CLOSE TO GALES THOUGH TUESDAY NIGHT INTO
WEDNESDAY MORNING. WINDS DIMINISH TO LESS THAN 25 KTS THURSDAY INTO
FRIDAY AS PRESSURE GRADIENT RELAXES. NEXT PERIOD OF STRONGER WINDS
WILL BE SATURDAY AS SOUTH WINDS INCREASE TO 30 KTS OVER THE EASTERN
LAKE AHEAD OF STRONGER LOW PRESSURE SYSTEM.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY FROM 10 PM THIS EVENING TO 7 AM EST
WEDNESDAY FOR MIZ001-003.
WIND ADVISORY UNTIL 10 AM EST THIS MORNING FOR MIZ013-014.
LAKE EFFECT SNOW ADVISORY FROM 10 PM EST /9 PM CST/ THIS EVENING
TO NOON EST /11 AM CST/ WEDNESDAY FOR MIZ002-009.
LAKE SUPERIOR...
GALE WARNING UNTIL 2 PM EST THIS AFTERNOON FOR LSZ266-267.
GALE WARNING UNTIL 11 AM EST THIS MORNING FOR LSZ263-264.
LAKE MICHIGAN...
GALE WARNING UNTIL NOON EST TODAY FOR LMZ248-250.
GALE WARNING UNTIL 7 AM EST THIS MORNING FOR LMZ221.
&&
$$
SHORT TERM...JLB
LONG TERM...JLA
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
644 AM EST MON NOV 25 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 516 AM EST MON NOV 25 2013
WV IMAGERY AND RUC ANALYSIS INDICATED WNW MID/UPPER LEVEL FLOW FROM
CNTRL CANADA THROUGH THE GREAT LAKES WITH ONE SHORTWAVE TROUGH FROM
NW ONTARIO INTO NW MN AND ANOTHER WELL TO THE NORTH MOVING INTO NRN
SASK. AT THE SFC...A TIGHT PRES GRADIENT PREVAILED ACROSS THE WRN
GREAT LAKES BTWN A 1000 MB LOW LOCATED JUST NORTH OF THUNDER BAY
ONTARIO AND A 1036 MB RIDGE OVER THE OH VALLEY. WITH THE STRONGEST
PRES FALLS MOVING TO THE NE OF LAKE SUPERIOR...VERY STRONG SW WINDS
PERSISTED ACROSS WRN LAKE SUPERIOR AND NRN LAKE MICHIGAN. WAA
LEADING TO INCREASING STABILITY HAS LIMITED MIXING OF 45-50 KNOT
925-850 MB WINDS TOWARD THE SFC EXCEPT OVER THE RELATIVELY WARM LAKE
MICHIGAN WATERS. GUSTS IN THE 35-40 KT RANGE PERSISTED FROM FAIRPORT
TO PORT INLAND WHERE A WIND ADVISORY WAS IN EFFECT. WINDS OVER
INLAND LOCATIONS AT ESC AND ISQ WERE ONLY GUSTING TO AROUND 25
KNOTS. RADAR INDICATED WEAK RETURNS...MAINLY OVER THE ERN CWA...WITH
SOME PATCHY LIGHT SNOW OR FLURRIES SUPPORTED BY 700-300 QVECTOR CONV
AND ISENTROPIC LIFT AHEAD OF THE UPSTREAM SHRTWV.
TODAY...EXPECT WINDS TO SUBSIDE BY THE 15Z WIND ADVISORY EXPIRATION
TIME AS THE CORE OF THE STRONGEST 925-850 MB WINDS SHIFTS OFF TO THE
EAST. AS THE AREA OF LIGHT SNOW MOVES TO THE EAST...SOME LAKE
ENHANCEMENT MAY BE POSSIBLE WITH THE SW FLOW OFF OF LAKE MICHIGAN
BUT SHOULD REMAIN MAINLY TO THE SOUTH AND EAST OF THE CWA. OVER THE
KEWEENAW...AN AREA OF LOW LEVEL CONV AS WINDS VEER FROM SW TO W MAY
BRING A BRIEF PERIOD OF LAKE ENHANCED SNOW. HOWEVER...MID LEVEL
DRYING WITH THE DRY SLOT AND MARGINAL INSTABILITY WITH 850 MB TEMPS
AROUND -7C (LAKE SFC NEAR 4C) SUPPORTS ONLY CHANCE POPS WITH ANY
ACCUMULATIONS ONLY AMOUNTING TO A HALF INCH OR LESS. INCREASING
850-700 MB MOISTURE AND AND 850/700 MB TEMPS DROPPING TO -10C/-17C
WITH THE APPROACH OF THE SHRTWV WILL ALSO BRING AN INCREASE IN LAKE
ENHANCED SNOW INTO THE WEST AND THE ERN SHORELINE FROM PICTURED
ROCKS TO GRAND MARAIS.
TONIGHT...STRONGER CAA DROPPING 850 MB TEMPS TO AROUND -18C BOOSTING
LAKE INDUCED CAPES TO NEAR 700 J/KG ALONG WITH STRENGTHENING
CYCLONIC NW FLOW WILL BRING A FURTHER INCREASE IN LES INTO THE WEST.
THE HIGH RES MODELS OFFER A VARIETY OF SOLUTIONS AS TO WHERE THE
HEAVIER SNOW BANDS WILL FOCUS AND DELAY THE STRONGER VEERING WIND
SHIFT AND LOW LEVEL CONV BAND MOVING IN TIL AFT 12Z. ALTHOUGH
SEVERAL INDICATE THE GREATER SNOW POTENTIAL INTO THE KEWEENAW AND
IRONWOOD AREAS...CONFIDENCE IN IN HIGHLIGHTING ANY PARTICULAR
LOCATION IS LIMITED. SO...A GENERAL 2 TO 5 INCH FCST WAS INCLUDED
FOR MOST OF THE NW TO WNW FLOW SNOWBELTS IN THE WEST AS WELL AS
LOCATIONS NORTH OF M-28 EAST OF MUNISING.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 437 AM EST MON NOV 25 2013
EXTENT OF LAKE EFFECT SNOW AND SNOW AMOUNTS ALONG WITH THE NEED FOR
ANY ADVISORIES OR WARNINGS TUESDAY/TUESDAY NIGHT IS PRIMARY FOCUS.
IN LARGE SCALE...STRONG SHORTWAVE IN NORTHERN STREAM CURRENTLY OVER
NORTHERN MANTIOBA WILL BE CROSSING UPR MICHIGAN AND LK SUPERIOR ON
TUESDAY. NAM/GFS/ECMWF DECENT AGREEMENT WITH TIMING OF LARGER SCALE
IMPACTS AS THEY ALL SHOW H7-H5/H5-H3 Q-VECTOR CONVERGENCE INTO WESTERN
UPR MICHIGAN BEFORE 12Z TUESDAY SPREADING TO CNTRL CWA BY 18Z AND
EXITING EASTERN CWA BY 00Z WEDNESDAY. MAY SEE MINOR LGT SNOW EVEN
INTO SOUTH AS THE SHORTWAVE CROSSES THE REGION. BIGGEST IMPACT
THOUGH WILL BE ON LK EFFECT THAT BEGINS LATE TONIGHT. NAM AND GFS
FORECAST SOUNDINGS SHOW GOOD RESPONSE FM THE WAVE WITH INVERSION
HEIGHTS RISING ABOVE 5KFT LATE TONIGHT AND SPIKING UP TO 8-10KFT BY
MIDDAY TUESDAY. LAKE EQUILIBRIUM LEVELS INCREASE TO 13KFT AND LAKE
INDUCED CAPE VALUES CLIMB OVER 700J/KG AS H85 TEMPS FALL TO -17C TO
-20C BY TUESDAY NIGHT. SOUNDINGS ALSO INDICATE INCREASING MOISTURE
QUALITY TUESDAY INTO MOST OF TUESDAY NIGHT. SO...INSTABILITY AND
MOISTURE NOT THE ISSUE FOR MODERATE TO HEAVY SNOW. BOTH PARAMETERS
ARE THERE NO DOUBT. MAIN STICKING POINT FOR THE FORECAST ARE
LOW-LEVEL WIND FIELDS AND MORE SPECIFICALLY THE WIND DIRECTION WHICH
IS ALL SO CRITICAL FOR PEGGING WHERE HEAVIEST LK EFFECT WILL OCCUR.
UNFORTUNATELY...NOTEABLE DIFFERENCES EXIST BTWN THE NAM/NCEP HIGH
RES RUNS AND THE COARSER ECMWF/GFS AND ALSO THE GEM. MAIN ISSUE IS
HOW QUICKLY SOUTH TO BRING LOW-LEVEL WIND SHIFT PASSAGE ON TUESDAY.
PASSAGE OF THE TROUGH ESSENTIALLY KICKS LK EFFECT FM WNW/NW FLOW
AREAS TO AREAS FAVORED BY N/NNE WINDS. USUALLY LIKE THE NAM WITH
HIGHER RESOLUTION DETAILS...BUT SUCH A QUICK TROUGH PASSAGE AT
15Z-18Z ON TUESDAY IN THE NORTH SEEMS QUESTIONABLE AS SHORTWAVE
TROUGH AXIS IS STILL OVER CNTRL UPR MICHIGAN AT 18Z. WOULD EXPECT
THE TROUGH PASSAGE TO OCCUR TUESDAY EVENING IN THE WAKE OF THE
SHORTWAVE TROUGH CROSSING THE AREA. OVERALL...PREFERRED SOLUTION
IS PROBABLY MOST CLOSEST TO GFS/LOCAL REGIONAL WRF AND ECMWF.
WHAT THIS MEANS IN TERMS OF LK EFFECT SNOW IS EXPECT A PROLONGED
PERIOD OF LK EFFECT FOR WNW/NW FLOW AREAS LATE TONIGHT THROUGH LATE
TUESDAY AFTN /WHITE PINE TO ROCKLAND/TWIN LAKES AND MAYBE AS FAR
NORTH AS HOUGHTON/ AND ALSO OVER NORTHERN PARTS OF ALGER AND LUCE
COUNTIES. HEAVIER LK EFFECT THEN SHIFTS TO GOGEBIC/WESTERN ONTONAGON
AND MARQUETTE COUNTIES BY TUESDAY EVENING. BASED ON EXPECTED SLR/S
NEARING 20:1 OR EVEN ABOVE 20:1 AND QPF WHICH WAS BLEND OF REGIONAL
WRF AND EVENTUALLY THE WETTER NAM DNG LATER TUESDAY...SEEMS LIKE A
SOLID ADVY EVENT IS IN STORE WITH SNOW AMOUNTS OF 4-6/5-8 INCHES IN
THE 12 HOUR PERIOD FOR TUESDAY AND AGAIN ON TUESDAY NIGHT...THOUGH
THE LOCATIONS OF HEAVIEST SNOW SHOULD SHIFT AROUND AS WINDS IN THE
LAKE CONVECTIVE LAYER SO SOME SHEAR AND DO NOT STAY LOCKED IN THE
SAME DIRECTION FOR VERY LONG PERIOD OF TIME. SOME LOCATIONS IN THE
FAR WESTERN CWA /VCNTY OF IWD TO BERGLAND AND WHITE PINE/ MAY COME
CLOSER TO WARNING CRITERIA TUESDAY AFTN INTO TUESDAY NIGHT BUT SINCE
THE LARGER SCALE FORCING IS DIMINISHING WHEN WIND DIRECTION BECOMES
A MORE FAVORABLE N-NNE TO INCREASE CONVERGENCE IN THESE AREAS...WILL
OPT TO ISSUE THE ADVY AND LET FUTURE SHIFTS UPGRADE TO WARNING IF IT
IS NEEDED. SNOW WILL BE THE MAIN ISSUE WITH THIS EVENT. WINDS WILL
BE GUSTY 25-35 MPH...BUT STRONGEST WINDS AND BLSN/VSBY IMPACTS WILL
BE MORE OVER THE NORTHERN PARTS OF THE KEWEENAW ON TUESDAY AND
PERHAPS INTO NCNTRL UPR MICHIGAN ON TUESDAY NIGHT. NOT EXPECTING
WIDESPREAD BLSN AS THE EVENT THIS LAST WEEKEND HAD.
FOR NOW...COORDINATED WITH SHORT TERM FORECASTER AND PUT OUT LAKE
EFFECT SNOW ADVISORIES FOR WESTERN TIER. ADDITIONAL HEADLINES WILL
LIKELY BE ISSUED OVER NCNTRL AND POSSIBLY NORTHEAST CWA LATER TODAY
OR TONIGHT...BUT SINCE THE MORE SIGNIFICANT SNOW WILL NOT OCCUR IN
THESE AREAS UNTIL LATER TUESDAY OR EVEN AS LATE AS TUESDAY NIGHT IF
GFS IS COMPLETELY CORRECT...WILL NOT ISSUE THOSE HEADLINES NOW. NOT
ENOUGH CONFIDENCE THAT THESE AREAS WOULD SEE WARNING AMOUNTS SO DID
NOT WANT TO PUT A WATCH OUT EITHER.
SNOW SHOWERS PERSIST FOR N FLOW AREAS ON WEDNESDAY...BUT INTENSITY
WILL BE ON THE WANE WITH LOWERING INVERSION HEIGHTS TO AT OR BLO
5KFT. EVEN AS SNOW DIMINISHES...THE DGZ WILL BE IN THE HEART OF THE
LAKE CONVECTIVE LAYER SO WHAT SNOW SHOWERS ARE LEFTOVER ON WEDNESDAY
WILL BE THE EFFECIENT FLUFFY TYPE. WINDS WILL BE ON THE DECREASE AS
WELL...AS WILL BLSN/ASSOCIATED VSBY ISSUES. SINCE THE FLOW REMAINS
LGT NORTH ALL DAY AND INSTABILITY IS MORE THAN SUFFICIENT...SNOW
SHOWERS PROBABLY WILL NOT END COMPLETELY FOR FAR WEST OR NCNTRL BUT
THEY MAY BECOME PINNED CLOSER TO THE SHORELINES ON WEDNESDAY NIGHT
AS MESOSCALE EFFECTS/LAND BREEZES START TO DRIVE THE LOW-LEVEL
CONVERGENCE.
STILL COULD SEE SOME LGT SNOW ON THANKSGIVING. NO BIG IMPACT TO
TRAVEL EXPECTED THOUGH. BEST CHANCE OVER THE NORTHERN TIER. WEAK
TROUGH WORKS THROUGH THURSDAY NIGHT INTO FRIDAY. COULD SEE SOME SNOW
SHOWERS ACROSS KEWEENAW IN WNW FLOW ON FRIDAY. WEEKEND WILL FEATURE
MODEST WARMING TREND WITH SOME AREAS SLIGHTLY ABOVE FREEZING FOR
DAYTIME HIGHS. LGT SNOW MAY ACCOMPANY THIS WARM AIR ADVECTION BUT
LOOKS LIKE BETTER CHANCE FOR ANY SNOW ACCUMULATION WILL REMAIN TO
NORTH OF CWA.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 644 AM EST MON NOV 25 2013
AS A STRONG DISTURBANCE OVER NW ONTARIO AND ITS ATTENDANT SFC COLD
FRONT DIGS SE INTO THE NRN GREAT LAKES...EXPECT MVFR CIGS TO
DEVELOP OVER THE W AT IWD AND CMX THIS MORNING. WITH A STRONG
UPSLOPE W WIND...THE FROPA WILL ALSO BRING MVFR VSBY FOR A COUPLE
HOURS AT CMX THISMORNING. ALTHOUGH SOME MVFR CIGS MAY OCCUR AT SAW
WITH THE FROPA...DOWNSLOPE NATURE OF THE FLOW INDICATES THIS
CONDITION WL BE MARGINAL AND MAY REMAIN VFR. THE BEST CHANCE OF MORE
PERSISTENT MVFR WX WILL BE AT CMX WITH A MORE PRONOUNCED UPSLOPE W
WIND...WHICH WILL GUST AS HIGH AS 30 KTS WITH A SLOW INFLUX
OF COLDER AIR/MORE DESTABILIZATION. THE APPROACH OF ANOTHER
DISTURBANCE AND LOW PRES TROF MAY BRING ANOTHER ROUND OF HEAVIER
LES TO CMX THIS EVENING...SO FCST IFR VSBYS AT THIS SITE THEN.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 533 AM EST MON NOV 25 2013
SW TO W GALES OVER LAKE SUPERIOR THIS MORNING ARE EXPECTED TO
DIMINISH BY LATE MORNING OVER THE WEST AND MID AFTERNOON OVER THE
EAST. THE PRES GRADIENT WILL WEAKEN AS A TROUGH MOVES THROUGH THE
LAKE AND LOW PRESSURE NORTH OF LAKE SUPERIOR MOVES TOWARD JAMES BAY.
NORTHWEST WINDS TO 25 KTS SHIFT TO THE NORTH TO 30 KTS LATER TUESDAY
AND TUESDAY NIGHT. MAY GET CLOSE TO GALES THOUGH TUESDAY NIGHT INTO
WEDNESDAY MORNING. WINDS DIMINISH TO LESS THAN 25 KTS THURSDAY INTO
FRIDAY AS PRESSURE GRADIENT RELAXES. NEXT PERIOD OF STRONGER WINDS
WILL BE SATURDAY AS SOUTH WINDS INCREASE TO 30 KTS OVER THE EASTERN
LAKE AHEAD OF STRONGER LOW PRESSURE SYSTEM.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY FROM 10 PM THIS EVENING TO 7 AM EST
WEDNESDAY FOR MIZ001-003.
WIND ADVISORY UNTIL 10 AM EST THIS MORNING FOR MIZ013-014.
LAKE EFFECT SNOW ADVISORY FROM 10 PM EST /9 PM CST/ THIS EVENING
TO NOON EST /11 AM CST/ WEDNESDAY FOR MIZ002-009.
LAKE SUPERIOR...
GALE WARNING UNTIL 2 PM EST THIS AFTERNOON FOR LSZ266-267.
GALE WARNING UNTIL 11 AM EST THIS MORNING FOR LSZ263-264.
LAKE MICHIGAN...
GALE WARNING UNTIL NOON EST TODAY FOR LMZ248-250.
GALE WARNING UNTIL 7 AM EST THIS MORNING FOR LMZ221.
&&
$$
SHORT TERM...JLB
LONG TERM...JLA
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS GAYLORD MI
630 AM EST MON NOV 25 2013
.SYNOPSIS...
ISSUED AT 449 AM EST MON NOV 25 2013
WINTRY CONDITIONS WILL BE PREVALENT ACROSS NORTHERN MICHIGAN THROUGH
THE THANKSGIVING HOLIDAY WEEK...WITH SEVERAL WEAKER WEATHER SYSTEMS
DELIVERING REPEATED SHOTS OF BOTH SYSTEM AND LAKE EFFECT SNOW. THE
FIRST WILL ARRIVE THIS MORNING...AS LOW PRESSURE TRACKS NEAR JAMES
BAY...BRINGING A ROUND OF SNOW TO MUCH OF NORTHWEST LOWER AND
EASTERN UPPER. A COLD FRONT WILL GRADUALLY WORK THROUGH THE REGION
LATER TUESDAY...BRINGING RENEWED COLD CONDITIONS ALONG WITH MORE
LAKE EFFECT SNOW. THAT GENERAL TREND WILL CONTINUE INTO THANKSGIVING
DAY...BEFORE QUIET WEATHER MAKES A RETURN TOWARD NEXT WEEKEND.
&&
.UPDATE...
ISSUED AT 629 AM EST MON NOV 25 2013
DEEP MOISTURE OUT AHEAD OF AN ADVANCING COLD FRONT IS STARTING TO
DEVELOP SNOWS ACROSS FAR NRN LAKE MICHIGAN AND THROUGH THE STRAITS
REGION. STILL DEFINITELY EXPECTING A RAPID PRODUCTION AND
INTENSIFICATION OF SNOWS IN A SW TO NE ORIENTED BAND...COMBINED
WITH VERY STRONG SW WIND GUSTS TO 50 MPH. THIS WILL BRING A PERIOD
OF MODERATE TO HEAVY SNOWS ACROSS MUCH OF NW LOWER AND EASTERN
SECTIONS OF CHIP/MACK COUNTIES THIS MORNING. ALREADY ISSUED THE
INITIAL SPS ALERTING OF RAPIDLY DEVELOPING HAZARDOUS DRIVING
CONDITIONS. FOLKS...PLEASE ALLOW EXTRA TIME TO REACH YOUR
DESTINATION. HIGH PROFILE VEHICLES WILL HAVE AN EXTRA BOOST TO THE
HAZARD DUE TO THE STRONG WINDS. DID INCREASE SNOWFALL ACROSS AN
AREAS SURROUNDING LEELANAU COUNTY...WHERE A LONGER PERIOD OF SNOWS
ARE EXPECTED THIS MORNING. OTHERWISE...THE FORECAST IS IN GOOD
SHAPE.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 449 AM EST MON NOV 25 2013
WELL...THAT WAS A NICE 12-ISH HOUR RESPITE FROM THE ACTIVE WEATHER.
NOW IT`S GAME ON ONCE AGAIN...WITH THE MAIN FORECAST ISSUES BEING OF
THE LAKE EFFECT/ENHANCEMENT VARIETY...ALONG WITH WIND ISSUES THROUGH
THE DAY TODAY. EARLY MORNING ANALYSIS PLACES VERY WEAK SHORTWAVE
RIDGE AXIS JUST TO THE EAST OF NORTHERN MICHIGAN...WITH DEEP AND
QUITE STRONG SOUTHWESTERLY FLOW WELL RAMPED UP ACROSS THE NORTHERN
LAKES IN ADVANCE OF ANOTHER STRONG UPPER WAVE QUICKLY AMPLIFYING
THROUGH SOUTHERN MANITOBA. INITIAL PUSH OF THAT WARM ADVECTION
EARLIER LED TO A BRIEF AXIS OF LIGHT SNOW MARCHING THROUGH
NORTHERN/EASTERN AREAS...WITH SECONDARY SURGE OF MUCH DEEPER AND
STRONGER ASCENT GOING INTO GRADUAL TOP-DOWN SATURATION OFF TO OUR
WEST AT THE MOMENT...AS EVIDENCED BY CEILINGS FALLING 5-8KFT OVER
THE PAST FEW HOURS. MEANWHILE...QUITE THE WINDY CONDITIONS HAVE
SHOWN UP RECENTLY AS CORE OF RATHER IMPRESSIVE 45-55 KNOT FLOW IS
ROLLING OVERHEAD...COMBINING WITH A REMNANT UNSTABLE AIRMASS ACROSS
THE LAKES TO PRODUCE SOME RATHER BEEFY WIND GUSTS PUSHING 50 MPH
ALONG THE LAKE MICHIGAN SHORE.
THE ABOVE MENTIONED WARM ADVECTION WILL BE IMPORTANT FOR OUR AREA
THIS MORNING...AS THE ADDED MOISTURE (FROM AN INITIALLY QUITE DRY
AIRMASS) GIVES A BIG BOOST OVER LAKE MICHIGAN. ALREADY SEEING THE
FIRST HINTS OF THIS RIGHT NOW...BUT THE THOUGHT IS THAT DEEPER
MOISTURE OVERRIDING THE LAKE WILL GO INTO THE RAPID PRODUCTION OF A
SOUTHWEST FLOW LAKE BAND THE NEXT FEW HOURS...WHICH WILL ULTIMATELY
GET PUNTED ONSHORE AS THE SHARP UPPER WAVE OVER MANITOBA WORKS
TOWARD OUR AREA. THESE TYPES OF SETUPS ALWAYS HAVE TROUBLE WRITTEN
ALL OVER THEM FROM AN IMPACT STANDPOINT...AS THERE SHOULD BE A
COUPLE HOUR WINDOW FOR SOME HEAVY SNOW TO FALL UP AND DOWN THE LAKE
MICHIGAN SHORELINE COUNTIES...AND PROBABLY EVEN FARTHER INLAND INTO
THE HIGHER TERRAIN WHERE UPSLOPE TYPICALLY WORKS ITS MAGIC IN SUCH A
SETUP. GIVEN WARMING THERMAL PROFILES...SNOW TO LIQUID RATIOS SHOULD
BE RATHER LOW...AS EVIDENCED BY A QUITE DEEP ISOTHERMAL LAYER AROUND
-6C PER FORECAST RAOBS...MAKING FOR MORE OF A GREASY/SLIPPERY SNOW.
THROW IN SOME QUITE GUSTY WINDS AND THE STAGE IS PROBABLY SET FOR A
PERIOD OF SLOPPY TRAVEL/LOW VSBYS ACROSS PRIMARILY NORTHWEST
LOWER...WITH A QUICK 2-3" OF SNOW EXPECTED TO FALL. LOCAL 4/12KM APX
WRF AND RECENT HRRR RUNS ARE EVEN MORE IMPRESSIVE...PAINTING AN AXIS
OF 0.4" OF LIQUID UP TOWARD CHARLEVOIX/EMMET/CHEBOYGAN/OTSEGO/ANTRIM
COUNTIES...WITH A SECONDARY MAXIMUM NEAR CADILLAC. GIVEN THE
EXPECTED LOWER RATIOS...SHOULDN`T SEE ACCUMULATION GET OUT OF
HAND...EVEN IF THE HIGHER QPF FORECASTS VERIFY. NOT SURE THIS WILL
BE WORTHY OF A WINTER WEATHER HEADLINE - PROBABLY MORE LIKE AN
SPS...ESPECIALLY CONSIDERING THE WORST CONDITIONS SHOULD OCCUR JUST
AFTER THE MORNING COMMUTE (MAINLY 9AM-1PM).
WINDS WILL SUBSIDE HEADING INTO THE AFTERNOON AS THE CORE OF
STRONGEST 950-900MB FLOW EXITS EAST...ALL WHILE DEEPER MOISTURE ALSO
STRIPS OUT. THAT LEAVES US IN MORE OF A LIGHT SNOW SHOWERS/SNIZZLE
REGIME FOR MUCH OF THE AFTERNOON AS SOUTHWEST FLOW CONTINUES BUT
WHILE CLOUD TOP TEMPS HOVER ONLY AROUND -8C. PROBABLY NOT LOOKING AT
MUCH ADDITIONAL ACCUMULATION FOR MOST AREAS THROUGH LATE AFTERNOON.
HOWEVER...MORE ISSUES SHOW UP BY EARLY EVENING WITH PERSISTENT HINTS
OF A STRONGER FRONTAL SNOW BAND BEING BROUGHT ASHORE INTO EASTERN
UPPER AS LOW PRESSURE NEARS THE SOUTHERN TIP OF JAMES BAY AND SWINGS
A COLD FRONT THROUGH THE EASTERN U.P. THAT FEATURE WILL IN ALL
LIKELIHOOD BECOME ABSORBED INTO THE LAKE AGGREGATE TROUGH OVER
EASTERN LAKE SUPERIOR...WITH PERHAPS EVEN A WEAK CIRCULATION CENTER
DEVELOPING IN RESPONSE TO YET ANOTHER STRONG UPPER WAVE ENTERING THE
ARROWHEAD OF MINNESOTA. THAT SETUP COULD LEAD TO ALL KINDS OF
MESOSCALE GARBAGE...BUT THE CLEAR SIGNAL IS FOR AN ENHANCED
CONVERGENCE BAND TO SKIRT FAR NORTHERN CHIPPEWA COUNTY...MAINLY
TOWARD PARADISE/WHITEFISH POINT...WITH MAYBE A COUPLE INCHES
POSSIBLE. FARTHER SOUTH...LOOKING LIKE PERSISTENT MORE NEBULOUS SNOW
SHOWERS WILL CONTINUE OVERNIGHT FOR SOUTHWEST FLOW AREAS ACROSS
NORTHWEST LOWER UP TOWARD DRUMMOND ISLAND. WAS A LITTLE CONCERNED
ABOUT SOME DRIZZLE POSSIBILITIES GIVEN INITIALLY SHALLOW NATURE OF
MOISTURE...BUT GRADUAL INTRUSION OF COLDER AIR ALOFT SHOULD FAVOR
ICE IN THE CLOUDS AS CLOUD TOP TEMPS END UP AROUND -12C BY 06Z. NO
MAJOR ACCUMULATION FORESEEN FOR NORTHERN LOWER OVERNIGHT.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 449 AM EST MON NOV 25 2013
A VERY ACTIVE AND RAPIDLY CHANGING WEATHER PATTERN WILL REMAIN
LOCKED IN ACROSS THE GREAT LAKES THROUGH THE THANKSGIVING HOLIDAY
WITH A SERIES OF SHORTWAVES AND SHOTS OF COLDER CANADIAN AIR
RESULTING IN A COUPLE OF ROUNDS OF LAKE EFFECT AND LAKE ENHANCED
SNOWFALL. THIS WILL ALSO PREVENT US FROM ANY SIGNIFICANT WARMING FOR
THE NEXT SEVERAL DAYS. A FAIRLY QUIET PERIOD OF WEATHER IS THEN
ANTICIPATED FOR FRIDAY THROUGH THE WEEKEND.
TUESDAY THROUGH WEDNESDAY NIGHT...A SIMILAR SET UP LIKE TODAY...IS
EXPECTED FOR TUESDAY WITH NEXT VIGOROUS SHORTWAVE...COLD FRONT AND
DEEPER MOISTURE ANTICIPATED TO MOVE IN ACROSS NRN MICHIGAN. THIS
TIME AROUND...WE WILL HAVE A BIT DEEPER INSTABILITY BUT LESS WIND.
WEST/WSW FLOW AHEAD OF THIS FRONT...H8 TEMPS COLDER IN THE -10C TO
-11C RANGE AND INVERSION HEIGHTS TO 7KFT WILL INCREASE TO NEAR 9KFT
WITH COLD ADVECTION THROUGH THE DAY...BUT A DRAMATIC SHIFT IN WINDS
TO OUT OF THE NNW INTO TUESDAY EVENING. MOISTURE IN THE LOWEST
LEVELS ARE STARTING TO LOOK A BIT MORE MOISTURE...MORE SO ON THIS
RUN OF THE BUFR SOUNDINGS. THE MOST IMPRESSIVE LES PARAMETERS ARE
REALLY FOCUSED TUESDAY EVENING AFTER THE FLOW TURNS NORTHERLY WITH
DEEPEST INSTABILITY WITH PASSAGE OF UPPER TROUGH AXIS/COLD AIR
ALOFT. THIS WILL FOCUS THE BEST ACCUMULATION POTENTIAL ACROSS THE
GTV BAY REGION AND AREAS SOUTH...WHERE ALSO...GUSTY WINDS COULD
LEAD TO BLOWING AND DRIFTING ISSUES. A CONSERVATIVE 3-6 INCHES OF
SNOW WILL BE POSSIBLE IN THIS REGION TUESDAY-TUESDAY NIGHT...LEADING
TO THE MOST HAZARDOUS DRIVING CONDITIONS EXPECTED IN THE LONG TERM
PORTION OF THE FORECAST. THE AIR MASS DRIES WITH LOWERING INVERSION
HEIGHTS INTO WEDNESDAY...HOWEVER CONTINUED COLD ADVECTION AND BEST
FETCH INTO GTV BAY WILL LEAD TO ANOTHER 1-2 INCHES OF SNOW
THERE...WHILE AMOUNTS ARE LESS IMPRESSIVE ELSEWHERE. FAR NE LOWER
NEAR ROGERS CITY/ALPENA AND OSCODA WILL SEE A SMATTERING OF 1 TO
MAYBE 3 INCH LOCAL AMOUNTS TUESDAY NIGHT INTO WEDNESDAY. WEDNESDAY
NIGHT...INVADING HIGHER PRESSURE AND LIGHTER WINDS FOR A LESSER
THREAT TO ANYTHING SIGNIFICANT IN THE SNOW DEPARTMENT.
HOWEVER...WILL HAVE TO KEEP AN EYE ON NEXT INCOMING SHORTWAVE AND
WARM ADVECTION OVER THE TOP OF THE REMAINING INSTABILITY...ALTHOUGH
MOST AREAS...LOOK TO HAVE A DISCONNECT FROM THE MOISTURE AND
ENHANCEMENT SEEDED FROM ALOFT. SLOWLY BACKING LOW LEVEL WINDS WILL
FOCUS ANY EMERGING THREAT OF RENEWED SNOW IN AND AROUND LAKE
MICHIGAN.
THANKSGIVING DAY AND NIGHT...THIS INCOMING WAVE IS RATHER WEAK
COMPARED TO IT`S PREDECESSORS....ALTHOUGH THE WARM ADVECTION/SEEDING
ALOFT DOES LOOK TO STILL HAVE SOME SORT OF ENHANCEMENT TO THE LAKE
EFFECT THROUGH THE HOLIDAY AND THURSDAY NIGHT. WINDS ARE EXPECTED TO
BE FAIRLY LIGHT...AND NOW SHIFTING ALL AROUND TO THE SW AS THIS
ENHANCEMENT PROCESS IN UNDERWAY...SPREADING SNOWS AROUND LAKE
MICHIGAN WITH LESS INLAND PENETRATION. THESE FINER DETAILS WILL
REALLY HAVE TO BE EXAMINED FURTHER OVER THE NEXT COUPLE OF DAYS TO
PROVIDE A MORE DETAILED HOLIDAY FORECAST. WIND DIRECTIONS AND SPEEDS
BEING THE MOST CRUCIAL...WHICH HAS A BIT OF UNCERTAINTY.
FRIDAY THROUGH SUNDAY...THIS WEAKER WAVE EXITS FRIDAY WITH SHALLOW
MID LEVEL RIDGING...AHEAD OF NEXT ADVERTISED SHORTWAVE ARRIVING
SATURDAY. A WEAK COLD FRONT LAYS ACROSS/WASHES OUT OVER NRN
MICHIGAN. COULD BE ONE LAST HOORAH OF SOME WEAKER LAKE EFFECT...BUT
THIS APPEARS TO BE THE LEAST OF CONCERN IN THE SERIES OF LAKE EFFECT
EVENTS. THIS MAINLY DUE TO THE CONTINUED LOW LEVEL WARM ADVECTION
AND GRADUAL EROSION OF THE OVERLAKE INSTABILITY. WILL HAVE RATHER
SMALL CHANCES FOR SNOW IN AND AROUND LAKE MICHIGAN IN THE SW FLOW
THAT PERSISTS INTO SUNDAY. TEMPERATURES WILL MODERATE BACK INTO THE
LOWER HALF OF THE 30S OVER THE WEEKEND.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 629 AM EST MON NOV 25 2013
HIGH LEVEL OF CONCERN THIS MORNING FOR THE AVIATION COMMUNITY. A
BAND OF MODERATE TO HEAVY SNOWFALL WILL ENTER INTO THE NW LOWER
AIRPORTS STARTING WITH PLN AT THE START OF THE TAF PERIOD...AND
REACHING TVC/MBL A FEW HOURS LATER. THIS BAND OF SNOW WILL RAPIDLY
INTENSIFY AND INCREASE IN COVERAGE THIS MORNING...AND COMBINE WITH
VERY STRONG WIND GUSTS OUT OF THE SW...MAXING OUT AT 40-50
MPH...ESPECIALLY AT MBL. THESE WINDS HAVE ALREADY SUBSTANTIALLY
MIXED DOWN TO THE SFC...AND THIS MECHANICAL MIXING IS STRONG
ENOUGH TO ELIMINATE ALL MENTION OF LLWS...BUT IT`S STILL BLOWING
VERY HARD ALOFT. WILL BRING IN A PERIOD OF IFR AT ALL AIRPORTS
EXCEPT APN...WHICH WILL LIKELY JUST SEE SOME MVFR CONDITION LATER
THIS MORNING/MIDDAY.
LAKE EFFECT SNOWS WILL CONTINUE THROUGH THE DAY AND NIGHT IN
DEVELOPING MORE WESTERLY FLOW...WHICH DOES DECREASE THROUGH
THE LATTER HALF OF THE DAY AN NIGHT. THIS PRIMARILY AFFECTS PLN
WHERE MVFR CONDITIONS WILL BE THE RULE. PERIODS OF MVFR CIGS/VSBYS
FOR TVC...TO A LESSER DEGREE AT MBL. SNOWS NOT GOING TO REACH APN.
A QUICK 1-3 INCHES OF SNOW IS DEFINITELY POSSIBLE THIS MORNING
WITH LIQUID TO SNOW RATIOS ON THE LOW END AT AROUND 10:1.
OVERALL CONFIDENCE IS HIGH FOR THE EVOLUTION OF THE DESCRIBED
WEATHER.
&&
.MARINE...
ISSUED AT 449 AM EST MON NOV 25 2013
A WINDY ONE OUT THERE TO START...WITH GALES FOR MOST OF THE WATERS.
THOSE WINDS WILL SUBSIDE LATER THIS AFTERNOON AND ESPECIALLY THIS
EVENING...THOUGH WILL REMAIN A BIT GUSTY IN THE 20-25 KNOT RANGE AS
IS TYPICAL FOR LATE NOVEMBER. WINDS WILL GRADUALLY COME AROUND TO
THE NORTHWEST ON TUESDAY AND THEN NORTH TUESDAY NIGHT AND
WEDNESDAY...WITH CONTINUED GUSTS OF 25-30 KNOTS EXPECTED. COULD SEE
A PERIOD OF GALES ON MAINLY LAKE MICHIGAN SOMETIME TUESDAY NIGHT...
BUT CONFIDENCE IN THAT IS LOW AT THIS TIME. HIGH PRESSURE WILL
FINALLY WIN THE BATTLE BY THURSDAY...WITH A RETURN TO A BRIEF PERIOD
OF MUCH LIGHTER WINDS OF THE 15 KNOTS OF LESS VARIETY.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...WIND ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR MIZ015-016-019-
020-025-031.
LH...GALE WARNING UNTIL 10 PM EST THIS EVENING FOR LHZ345>349.
LM...GALE WARNING UNTIL 10 PM EST THIS EVENING FOR LMZ323-341-342-
344>346.
LS...SMALL CRAFT ADVISORY UNTIL 10 PM EST THIS EVENING FOR LSZ321-322.
&&
$$
UPDATE...SD
SYNOPSIS...DL
SHORT TERM...DL
LONG TERM...SD
AVIATION...SD
MARINE...DL
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
533 AM EST MON NOV 25 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 516 AM EST MON NOV 25 2013
WV IMAGERY AND RUC ANALYSIS INDICATED WNW MID/UPPER LEVEL FLOW FROM
CNTRL CANADA THROUGH THE GREAT LAKES WITH ONE SHORTWAVE TROUGH FROM
NW ONTARIO INTO NW MN AND ANOTHER WELL TO THE NORTH MOVING INTO NRN
SASK. AT THE SFC...A TIGHT PRES GRADIENT PREVAILED ACROSS THE WRN
GREAT LAKES BTWN A 1000 MB LOW LOCATED JUST NORTH OF THUNDER BAY
ONTARIO AND A 1036 MB RIDGE OVER THE OH VALLEY. WITH THE STRONGEST
PRES FALLS MOVING TO THE NE OF LAKE SUPERIOR...VERY STRONG SW WINDS
PERSISTED ACROSS WRN LAKE SUPERIOR AND NRN LAKE MICHIGAN. WAA
LEADING TO INCREASING STABILITY HAS LIMITED MIXING OF 45-50 KNOT
925-850 MB WINDS TOWARD THE SFC EXCEPT OVER THE RELATIVELY WARM LAKE
MICHIGAN WATERS. GUSTS IN THE 35-40 KT RANGE PERSISTED FROM FAIRPORT
TO PORT INLAND WHERE A WIND ADVISORY WAS IN EFFECT. WINDS OVER
INLAND LOCATIONS AT ESC AND ISQ WERE ONLY GUSTING TO AROUND 25
KNOTS. RADAR INDICATED WEAK RETURNS...MAINLY OVER THE ERN CWA...WITH
SOME PATCHY LIGHT SNOW OR FLURRIES SUPPORTED BY 700-300 QVECTOR CONV
AND ISENTROPIC LIFT AHEAD OF THE UPSTREAM SHRTWV.
TODAY...EXPECT WINDS TO SUBSIDE BY THE 15Z WIND ADVISORY EXPIRATION
TIME AS THE CORE OF THE STRONGEST 925-850 MB WINDS SHIFTS OFF TO THE
EAST. AS THE AREA OF LIGHT SNOW MOVES TO THE EAST...SOME LAKE
ENHANCEMENT MAY BE POSSIBLE WITH THE SW FLOW OFF OF LAKE MICHIGAN
BUT SHOULD REMAIN MAINLY TO THE SOUTH AND EAST OF THE CWA. OVER THE
KEWEENAW...AN AREA OF LOW LEVEL CONV AS WINDS VEER FROM SW TO W MAY
BRING A BRIEF PERIOD OF LAKE ENHANCED SNOW. HOWEVER...MID LEVEL
DRYING WITH THE DRY SLOT AND MARGINAL INSTABILITY WITH 850 MB TEMPS
AROUND -7C (LAKE SFC NEAR 4C) SUPPORTS ONLY CHANCE POPS WITH ANY
ACCUMULATIONS ONLY AMOUNTING TO A HALF INCH OR LESS. INCREASING
850-700 MB MOISTURE AND AND 850/700 MB TEMPS DROPPING TO -10C/-17C
WITH THE APPROACH OF THE SHRTWV WILL ALSO BRING AN INCREASE IN LAKE
ENHANCED SNOW INTO THE WEST AND THE ERN SHORELINE FROM PICTURED
ROCKS TO GRAND MARAIS.
TONIGHT...STRONGER CAA DROPPING 850 MB TEMPS TO AROUND -18C BOOSTING
LAKE INDUCED CAPES TO NEAR 700 J/KG ALONG WITH STRENGTHENING
CYCLONIC NW FLOW WILL BRING A FURTHER INCREASE IN LES INTO THE WEST.
THE HIGH RES MODELS OFFER A VARIETY OF SOLUTIONS AS TO WHERE THE
HEAVIER SNOW BANDS WILL FOCUS AND DELAY THE STRONGER VEERING WIND
SHIFT AND LOW LEVEL CONV BAND MOVING IN TIL AFT 12Z. ALTHOUGH
SEVERAL INDICATE THE GREATER SNOW POTENTIAL INTO THE KEWEENAW AND
IRONWOOD AREAS...CONFIDENCE IN IN HIGHLIGHTING ANY PARTICULAR
LOCATION IS LIMITED. SO...A GENERAL 2 TO 5 INCH FCST WAS INCLUDED
FOR MOST OF THE NW TO WNW FLOW SNOWBELTS IN THE WEST AS WELL AS
LOCATIONS NORTH OF M-28 EAST OF MUNISING.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 437 AM EST MON NOV 25 2013
EXTENT OF LAKE EFFECT SNOW AND SNOW AMOUNTS ALONG WITH THE NEED FOR
ANY ADVISORIES OR WARNINGS TUESDAY/TUESDAY NIGHT IS PRIMARY FOCUS.
IN LARGE SCALE...STRONG SHORTWAVE IN NORTHERN STREAM CURRENTLY OVER
NORTHERN MANTIOBA WILL BE CROSSING UPR MICHIGAN AND LK SUPERIOR ON
TUESDAY. NAM/GFS/ECMWF DECENT AGREEMENT WITH TIMING OF LARGER SCALE
IMPACTS AS THEY ALL SHOW H7-H5/H5-H3 Q-VECTOR CONVERGENCE INTO WESTERN
UPR MICHIGAN BEFORE 12Z TUESDAY SPREADING TO CNTRL CWA BY 18Z AND
EXITING EASTERN CWA BY 00Z WEDNESDAY. MAY SEE MINOR LGT SNOW EVEN
INTO SOUTH AS THE SHORTWAVE CROSSES THE REGION. BIGGEST IMPACT
THOUGH WILL BE ON LK EFFECT THAT BEGINS LATE TONIGHT. NAM AND GFS
FORECAST SOUNDINGS SHOW GOOD RESPONSE FM THE WAVE WITH INVERSION
HEIGHTS RISING ABOVE 5KFT LATE TONIGHT AND SPIKING UP TO 8-10KFT BY
MIDDAY TUESDAY. LAKE EQUILIBRIUM LEVELS INCREASE TO 13KFT AND LAKE
INDUCED CAPE VALUES CLIMB OVER 700J/KG AS H85 TEMPS FALL TO -17C TO
-20C BY TUESDAY NIGHT. SOUNDINGS ALSO INDICATE INCREASING MOISTURE
QUALITY TUESDAY INTO MOST OF TUESDAY NIGHT. SO...INSTABILITY AND
MOISTURE NOT THE ISSUE FOR MODERATE TO HEAVY SNOW. BOTH PARAMETERS
ARE THERE NO DOUBT. MAIN STICKING POINT FOR THE FORECAST ARE
LOW-LEVEL WIND FIELDS AND MORE SPECIFICALLY THE WIND DIRECTION WHICH
IS ALL SO CRITICAL FOR PEGGING WHERE HEAVIEST LK EFFECT WILL OCCUR.
UNFORTUNATELY...NOTEABLE DIFFERENCES EXIST BTWN THE NAM/NCEP HIGH
RES RUNS AND THE COARSER ECMWF/GFS AND ALSO THE GEM. MAIN ISSUE IS
HOW QUICKLY SOUTH TO BRING LOW-LEVEL WIND SHIFT PASSAGE ON TUESDAY.
PASSAGE OF THE TROUGH ESSENTIALLY KICKS LK EFFECT FM WNW/NW FLOW
AREAS TO AREAS FAVORED BY N/NNE WINDS. USUALLY LIKE THE NAM WITH
HIGHER RESOLUTION DETAILS...BUT SUCH A QUICK TROUGH PASSAGE AT
15Z-18Z ON TUESDAY IN THE NORTH SEEMS QUESTIONABLE AS SHORTWAVE
TROUGH AXIS IS STILL OVER CNTRL UPR MICHIGAN AT 18Z. WOULD EXPECT
THE TROUGH PASSAGE TO OCCUR TUESDAY EVENING IN THE WAKE OF THE
SHORTWAVE TROUGH CROSSING THE AREA. OVERALL...PREFERRED SOLUTION
IS PROBABLY MOST CLOSEST TO GFS/LOCAL REGIONAL WRF AND ECMWF.
WHAT THIS MEANS IN TERMS OF LK EFFECT SNOW IS EXPECT A PROLONGED
PERIOD OF LK EFFECT FOR WNW/NW FLOW AREAS LATE TONIGHT THROUGH LATE
TUESDAY AFTN /WHITE PINE TO ROCKLAND/TWIN LAKES AND MAYBE AS FAR
NORTH AS HOUGHTON/ AND ALSO OVER NORTHERN PARTS OF ALGER AND LUCE
COUNTIES. HEAVIER LK EFFECT THEN SHIFTS TO GOGEBIC/WESTERN ONTONAGON
AND MARQUETTE COUNTIES BY TUESDAY EVENING. BASED ON EXPECTED SLR/S
NEARING 20:1 OR EVEN ABOVE 20:1 AND QPF WHICH WAS BLEND OF REGIONAL
WRF AND EVENTUALLY THE WETTER NAM DNG LATER TUESDAY...SEEMS LIKE A
SOLID ADVY EVENT IS IN STORE WITH SNOW AMOUNTS OF 4-6/5-8 INCHES IN
THE 12 HOUR PERIOD FOR TUESDAY AND AGAIN ON TUESDAY NIGHT...THOUGH
THE LOCATIONS OF HEAVIEST SNOW SHOULD SHIFT AROUND AS WINDS IN THE
LAKE CONVECTIVE LAYER SO SOME SHEAR AND DO NOT STAY LOCKED IN THE
SAME DIRECTION FOR VERY LONG PERIOD OF TIME. SOME LOCATIONS IN THE
FAR WESTERN CWA /VCNTY OF IWD TO BERGLAND AND WHITE PINE/ MAY COME
CLOSER TO WARNING CRITERIA TUESDAY AFTN INTO TUESDAY NIGHT BUT SINCE
THE LARGER SCALE FORCING IS DIMINISHING WHEN WIND DIRECTION BECOMES
A MORE FAVORABLE N-NNE TO INCREASE CONVERGENCE IN THESE AREAS...WILL
OPT TO ISSUE THE ADVY AND LET FUTURE SHIFTS UPGRADE TO WARNING IF IT
IS NEEDED. SNOW WILL BE THE MAIN ISSUE WITH THIS EVENT. WINDS WILL
BE GUSTY 25-35 MPH...BUT STRONGEST WINDS AND BLSN/VSBY IMPACTS WILL
BE MORE OVER THE NORTHERN PARTS OF THE KEWEENAW ON TUESDAY AND
PERHAPS INTO NCNTRL UPR MICHIGAN ON TUESDAY NIGHT. NOT EXPECTING
WIDESPREAD BLSN AS THE EVENT THIS LAST WEEKEND HAD.
FOR NOW...COORDINATED WITH SHORT TERM FORECASTER AND PUT OUT LAKE
EFFECT SNOW ADVISORIES FOR WESTERN TIER. ADDITIONAL HEADLINES WILL
LIKELY BE ISSUED OVER NCNTRL AND POSSIBLY NORTHEAST CWA LATER TODAY
OR TONIGHT...BUT SINCE THE MORE SIGNIFICANT SNOW WILL NOT OCCUR IN
THESE AREAS UNTIL LATER TUESDAY OR EVEN AS LATE AS TUESDAY NIGHT IF
GFS IS COMPLETELY CORRECT...WILL NOT ISSUE THOSE HEADLINES NOW. NOT
ENOUGH CONFIDENCE THAT THESE AREAS WOULD SEE WARNING AMOUNTS SO DID
NOT WANT TO PUT A WATCH OUT EITHER.
SNOW SHOWERS PERSIST FOR N FLOW AREAS ON WEDNESDAY...BUT INTENSITY
WILL BE ON THE WANE WITH LOWERING INVERSION HEIGHTS TO AT OR BLO
5KFT. EVEN AS SNOW DIMINISHES...THE DGZ WILL BE IN THE HEART OF THE
LAKE CONVECTIVE LAYER SO WHAT SNOW SHOWERS ARE LEFTOVER ON WEDNESDAY
WILL BE THE EFFECIENT FLUFFY TYPE. WINDS WILL BE ON THE DECREASE AS
WELL...AS WILL BLSN/ASSOCIATED VSBY ISSUES. SINCE THE FLOW REMAINS
LGT NORTH ALL DAY AND INSTABILITY IS MORE THAN SUFFICIENT...SNOW
SHOWERS PROBABLY WILL NOT END COMPLETELY FOR FAR WEST OR NCNTRL BUT
THEY MAY BECOME PINNED CLOSER TO THE SHORELINES ON WEDNESDAY NIGHT
AS MESOSCALE EFFECTS/LAND BREEZES START TO DRIVE THE LOW-LEVEL
CONVERGENCE.
STILL COULD SEE SOME LGT SNOW ON THANKSGIVING. NO BIG IMPACT TO
TRAVEL EXPECTED THOUGH. BEST CHANCE OVER THE NORTHERN TIER. WEAK
TROUGH WORKS THROUGH THURSDAY NIGHT INTO FRIDAY. COULD SEE SOME SNOW
SHOWERS ACROSS KEWEENAW IN WNW FLOW ON FRIDAY. WEEKEND WILL FEATURE
MODEST WARMING TREND WITH SOME AREAS SLIGHTLY ABOVE FREEZING FOR
DAYTIME HIGHS. LGT SNOW MAY ACCOMPANY THIS WARM AIR ADVECTION BUT
LOOKS LIKE BETTER CHANCE FOR ANY SNOW ACCUMULATION WILL REMAIN TO
NORTH OF CWA.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY MORNING) ISSUED AT
520 AM EST MON NOV 25 2013
A GUSTY SW WIND APRCHG 30 KTS AT IWD WL ADVECT LLVL DRY AIR INTO UPR
MI EARLY THIS MRNG...SO EXPECT VFR CONDITIONS DESPITE QUITE A BIT OF
MID CLD COVER. BUT AS A STRONG DISTURBANCE NOW NEAR LK WINNIPEG AND
ITS ATTENDANT SFC COLD FNT DIG SEWD TOWARD THE UPR LKS...EXPECT MVFR
CONDITIONS TO DVLP OVER THE W AT IWD AND CMX BY SUNRISE. WITH A
STRONG UPSLOPE W WIND...THE FROPA WL BRING IFR CONDITIONS FOR A
COUPLE HRS AT CMX DURING THE MRNG. ALTHOUGH SOME MVFR CIGS MAY OCCUR
AT SAW WITH THE FROPA...DOWNSLOPE NATURE OF THE FLOW INDICATES THIS
CONDITION WL BE MARGINAL AND MAY REMAIN VFR. THE BEST CHC OF MORE
PERSISTENT MVFR WX ON MON WL BE AT CMX WITH A MORE PRONOUNCED
UPSLOPE W WIND...WHICH WL GUST AS HI AS 30 KTS AT THIS EXPOSED
LOCATION WITH A SLOW INFLUX OF COLDER AIR/MORE DESTABILIZATION. THE
APRCH OF ANOTHER DISTURBANCE/LO PRES TROF MAY BRING ANOTHER ROUND OF
HEAVIER LES TO CMX THIS EVNG...SO FCST IFR VSBYS AT THIS SITE THEN.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 533 AM EST MON NOV 25 2013
SW TO W GALES OVER LAKE SUPERIOR THIS MORNING ARE EXPECTED TO
DIMINISH BY LATE MORNING OVER THE WEST AND MID AFTERNOON OVER THE
EAST. THE PRES GRADIENT WILL WEAKEN AS A TROUGH MOVES THROUGH THE
LAKE AND LOW PRESSURE NORTH OF LAKE SUPERIOR MOVES TOWARD JAMES BAY.
NORTHWEST WINDS TO 25 KTS SHIFT TO THE NORTH TO 30 KTS LATER TUESDAY
AND TUESDAY NIGHT. MAY GET CLOSE TO GALES THOUGH TUESDAY NIGHT INTO
WEDNESDAY MORNING. WINDS DIMINISH TO LESS THAN 25 KTS THURSDAY INTO
FRIDAY AS PRESSURE GRADIENT RELAXES. NEXT PERIOD OF STRONGER WINDS
WILL BE SATURDAY AS SOUTH WINDS INCREASE TO 30 KTS OVER THE EASTERN
LAKE AHEAD OF STRONGER LOW PRESSURE SYSTEM.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY FROM 10 PM THIS EVENING TO 7 AM EST
WEDNESDAY FOR MIZ001-003.
WIND ADVISORY UNTIL 10 AM EST THIS MORNING FOR MIZ013-014.
LAKE EFFECT SNOW ADVISORY FROM 10 PM EST /9 PM CST/ THIS EVENING
TO NOON EST /11 AM CST/ WEDNESDAY FOR MIZ002-009.
LAKE SUPERIOR...
GALE WARNING UNTIL 2 PM EST THIS AFTERNOON FOR LSZ266-267.
GALE WARNING UNTIL 11 AM EST THIS MORNING FOR LSZ263-264.
LAKE MICHIGAN...
GALE WARNING UNTIL NOON EST TODAY FOR LMZ248-250.
GALE WARNING UNTIL 7 AM EST THIS MORNING FOR LMZ221.
&&
$$
SHORT TERM...JLB
LONG TERM...JLA
AVIATION...KC
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
520 AM EST MON NOV 25 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 516 AM EST MON NOV 25 2013
WV IMAGERY AND RUC ANALYSIS INDICATED WNW MID/UPPER LEVEL FLOW FROM
CNTRL CANADA THROUGH THE GREAT LAKES WITH ONE SHORTWAVE TROUGH FROM
NW ONTARIO INTO NW MN AND ANOTHER WELL TO THE NORTH MOVING INTO NRN
SASK. AT THE SFC...A TIGHT PRES GRADIENT PREVAILED ACROSS THE WRN
GREAT LAKES BTWN A 1000 MB LOW LOCATED JUST NORTH OF THUNDER BAY
ONTARIO AND A 1036 MB RIDGE OVER THE OH VALLEY. WITH THE STRONGEST
PRES FALLS MOVING TO THE NE OF LAKE SUPERIOR...VERY STRONG SW WINDS
PERSISTED ACROSS WRN LAKE SUPERIOR AND NRN LAKE MICHIGAN. WAA
LEADING TO INCREASING STABILITY HAS LIMITED MIXING OF 45-50 KNOT
925-850 MB WINDS TOWARD THE SFC EXCEPT OVER THE RELATIVELY WARM LAKE
MICHIGAN WATERS. GUSTS IN THE 35-40 KT RANGE PERSISTED FROM FAIRPORT
TO PORT INLAND WHERE A WIND ADVISORY WAS IN EFFECT. WINDS OVER
INLAND LOCATIONS AT ESC AND ISQ WERE ONLY GUSTING TO AROUND 25
KNOTS. RADAR INDICATED WEAK RETURNS...MAINLY OVER THE ERN CWA...WITH
SOME PATCHY LIGHT SNOW OR FLURRIES SUPPORTED BY 700-300 QVECTOR CONV
AND ISENTROPIC LIFT AHEAD OF THE UPSTREAM SHRTWV.
TODAY...EXPECT WINDS TO SUBSIDE BY THE 15Z WIND ADVISORY EXPIRATION
TIME AS THE CORE OF THE STRONGEST 925-850 MB WINDS SHIFTS OFF TO THE
EAST. AS THE AREA OF LIGHT SNOW MOVES TO THE EAST...SOME LAKE
ENHANCEMENT MAY BE POSSIBLE WITH THE SW FLOW OFF OF LAKE MICHIGAN
BUT SHOULD REMAIN MAINLY TO THE SOUTH AND EAST OF THE CWA. OVER THE
KEWEENAW...AN AREA OF LOW LEVEL CONV AS WINDS VEER FROM SW TO W MAY
BRING A BRIEF PERIOD OF LAKE ENHANCED SNOW. HOWEVER...MID LEVEL
DRYING WITH THE DRY SLOT AND MARGINAL INSTABILITY WITH 850 MB TEMPS
AROUND -7C (LAKE SFC NEAR 4C) SUPPORTS ONLY CHANCE POPS WITH ANY
ACCUMULATIONS ONLY AMOUNTING TO A HALF INCH OR LESS. INCREASING
850-700 MB MOISTURE AND AND 850/700 MB TEMPS DROPPING TO -10C/-17C
WITH THE APPROACH OF THE SHRTWV WILL ALSO BRING AN INCREASE IN LAKE
ENHANCED SNOW INTO THE WEST AND THE ERN SHORELINE FROM PICTURED
ROCKS TO GRAND MARAIS.
TONIGHT...STRONGER CAA DROPPING 850 MB TEMPS TO AROUND -18C BOOSTING
LAKE INDUCED CAPES TO NEAR 700 J/KG ALONG WITH STRENGTHENING
CYCLONIC NW FLOW WILL BRING A FURTHER INCREASE IN LES INTO THE WEST.
THE HIGH RES MODELS OFFER A VARIETY OF SOLUTIONS AS TO WHERE THE
HEAVIER SNOW BANDS WILL FOCUS AND DELAY THE STRONGER VEERING WIND
SHIFT AND LOW LEVEL CONV BAND MOVING IN TIL AFT 12Z. ALTHOUGH
SEVERAL INDICATE THE GREATER SNOW POTENTIAL INTO THE KEWEENAW AND
IRONWOOD AREAS...CONFIDENCE IN IN HIGHLIGHTING ANY PARTICULAR
LOCATION IS LIMITED. SO...A GENERAL 2 TO 5 INCH FCST WAS INCLUDED
FOR MOST OF THE NW TO WNW FLOW SNOWBELTS IN THE WEST AS WELL AS
LOCATIONS NORTH OF M-28 EAST OF MUNISING.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 437 AM EST MON NOV 25 2013
EXTENT OF LAKE EFFECT SNOW AND SNOW AMOUNTS ALONG WITH THE NEED FOR
ANY ADVISORIES OR WARNINGS TUESDAY/TUESDAY NIGHT IS PRIMARY FOCUS.
IN LARGE SCALE...STRONG SHORTWAVE IN NORTHERN STREAM CURRENTLY OVER
NORTHERN MANTIOBA WILL BE CROSSING UPR MICHIGAN AND LK SUPERIOR ON
TUESDAY. NAM/GFS/ECMWF DECENT AGREEMENT WITH TIMING OF LARGER SCALE
IMPACTS AS THEY ALL SHOW H7-H5/H5-H3 Q-VECTOR CONVERGENCE INTO WESTERN
UPR MICHIGAN BEFORE 12Z TUESDAY SPREADING TO CNTRL CWA BY 18Z AND
EXITING EASTERN CWA BY 00Z WEDNESDAY. MAY SEE MINOR LGT SNOW EVEN
INTO SOUTH AS THE SHORTWAVE CROSSES THE REGION. BIGGEST IMPACT
THOUGH WILL BE ON LK EFFECT THAT BEGINS LATE TONIGHT. NAM AND GFS
FORECAST SOUNDINGS SHOW GOOD RESPONSE FM THE WAVE WITH INVERSION
HEIGHTS RISING ABOVE 5KFT LATE TONIGHT AND SPIKING UP TO 8-10KFT BY
MIDDAY TUESDAY. LAKE EQUILIBRIUM LEVELS INCREASE TO 13KFT AND LAKE
INDUCED CAPE VALUES CLIMB OVER 700J/KG AS H85 TEMPS FALL TO -17C TO
-20C BY TUESDAY NIGHT. SOUNDINGS ALSO INDICATE INCREASING MOISTURE
QUALITY TUESDAY INTO MOST OF TUESDAY NIGHT. SO...INSTABILITY AND
MOISTURE NOT THE ISSUE FOR MODERATE TO HEAVY SNOW. BOTH PARAMETERS
ARE THERE NO DOUBT. MAIN STICKING POINT FOR THE FORECAST ARE
LOW-LEVEL WIND FIELDS AND MORE SPECIFICALLY THE WIND DIRECTION WHICH
IS ALL SO CRITICAL FOR PEGGING WHERE HEAVIEST LK EFFECT WILL OCCUR.
UNFORTUNATELY...NOTEABLE DIFFERENCES EXIST BTWN THE NAM/NCEP HIGH
RES RUNS AND THE COARSER ECMWF/GFS AND ALSO THE GEM. MAIN ISSUE IS
HOW QUICKLY SOUTH TO BRING LOW-LEVEL WIND SHIFT PASSAGE ON TUESDAY.
PASSAGE OF THE TROUGH ESSENTIALLY KICKS LK EFFECT FM WNW/NW FLOW
AREAS TO AREAS FAVORED BY N/NNE WINDS. USUALLY LIKE THE NAM WITH
HIGHER RESOLUTION DETAILS...BUT SUCH A QUICK TROUGH PASSAGE AT
15Z-18Z ON TUESDAY IN THE NORTH SEEMS QUESTIONABLE AS SHORTWAVE
TROUGH AXIS IS STILL OVER CNTRL UPR MICHIGAN AT 18Z. WOULD EXPECT
THE TROUGH PASSAGE TO OCCUR TUESDAY EVENING IN THE WAKE OF THE
SHORTWAVE TROUGH CROSSING THE AREA. OVERALL...PREFERRED SOLUTION
IS PROBABLY MOST CLOSEST TO GFS/LOCAL REGIONAL WRF AND ECMWF.
WHAT THIS MEANS IN TERMS OF LK EFFECT SNOW IS EXPECT A PROLONGED
PERIOD OF LK EFFECT FOR WNW/NW FLOW AREAS LATE TONIGHT THROUGH LATE
TUESDAY AFTN /WHITE PINE TO ROCKLAND/TWIN LAKES AND MAYBE AS FAR
NORTH AS HOUGHTON/ AND ALSO OVER NORTHERN PARTS OF ALGER AND LUCE
COUNTIES. HEAVIER LK EFFECT THEN SHIFTS TO GOGEBIC/WESTERN ONTONAGON
AND MARQUETTE COUNTIES BY TUESDAY EVENING. BASED ON EXPECTED SLR/S
NEARING 20:1 OR EVEN ABOVE 20:1 AND QPF WHICH WAS BLEND OF REGIONAL
WRF AND EVENTUALLY THE WETTER NAM DNG LATER TUESDAY...SEEMS LIKE A
SOLID ADVY EVENT IS IN STORE WITH SNOW AMOUNTS OF 4-6/5-8 INCHES IN
THE 12 HOUR PERIOD FOR TUESDAY AND AGAIN ON TUESDAY NIGHT...THOUGH
THE LOCATIONS OF HEAVIEST SNOW SHOULD SHIFT AROUND AS WINDS IN THE
LAKE CONVECTIVE LAYER SO SOME SHEAR AND DO NOT STAY LOCKED IN THE
SAME DIRECTION FOR VERY LONG PERIOD OF TIME. SOME LOCATIONS IN THE
FAR WESTERN CWA /VCNTY OF IWD TO BERGLAND AND WHITE PINE/ MAY COME
CLOSER TO WARNING CRITERIA TUESDAY AFTN INTO TUESDAY NIGHT BUT SINCE
THE LARGER SCALE FORCING IS DIMINISHING WHEN WIND DIRECTION BECOMES
A MORE FAVORABLE N-NNE TO INCREASE CONVERGENCE IN THESE AREAS...WILL
OPT TO ISSUE THE ADVY AND LET FUTURE SHIFTS UPGRADE TO WARNING IF IT
IS NEEDED. SNOW WILL BE THE MAIN ISSUE WITH THIS EVENT. WINDS WILL
BE GUSTY 25-35 MPH...BUT STRONGEST WINDS AND BLSN/VSBY IMPACTS WILL
BE MORE OVER THE NORTHERN PARTS OF THE KEWEENAW ON TUESDAY AND
PERHAPS INTO NCNTRL UPR MICHIGAN ON TUESDAY NIGHT. NOT EXPECTING
WIDESPREAD BLSN AS THE EVENT THIS LAST WEEKEND HAD.
FOR NOW...COORDINATED WITH SHORT TERM FORECASTER AND PUT OUT LAKE
EFFECT SNOW ADVISORIES FOR WESTERN TIER. ADDITIONAL HEADLINES WILL
LIKELY BE ISSUED OVER NCNTRL AND POSSIBLY NORTHEAST CWA LATER TODAY
OR TONIGHT...BUT SINCE THE MORE SIGNIFICANT SNOW WILL NOT OCCUR IN
THESE AREAS UNTIL LATER TUESDAY OR EVEN AS LATE AS TUESDAY NIGHT IF
GFS IS COMPLETELY CORRECT...WILL NOT ISSUE THOSE HEADLINES NOW. NOT
ENOUGH CONFIDENCE THAT THESE AREAS WOULD SEE WARNING AMOUNTS SO DID
NOT WANT TO PUT A WATCH OUT EITHER.
SNOW SHOWERS PERSIST FOR N FLOW AREAS ON WEDNESDAY...BUT INTENSITY
WILL BE ON THE WANE WITH LOWERING INVERSION HEIGHTS TO AT OR BLO
5KFT. EVEN AS SNOW DIMINISHES...THE DGZ WILL BE IN THE HEART OF THE
LAKE CONVECTIVE LAYER SO WHAT SNOW SHOWERS ARE LEFTOVER ON WEDNESDAY
WILL BE THE EFFECIENT FLUFFY TYPE. WINDS WILL BE ON THE DECREASE AS
WELL...AS WILL BLSN/ASSOCIATED VSBY ISSUES. SINCE THE FLOW REMAINS
LGT NORTH ALL DAY AND INSTABILITY IS MORE THAN SUFFICIENT...SNOW
SHOWERS PROBABLY WILL NOT END COMPLETELY FOR FAR WEST OR NCNTRL BUT
THEY MAY BECOME PINNED CLOSER TO THE SHORELINES ON WEDNESDAY NIGHT
AS MESOSCALE EFFECTS/LAND BREEZES START TO DRIVE THE LOW-LEVEL
CONVERGENCE.
STILL COULD SEE SOME LGT SNOW ON THANKSGIVING. NO BIG IMPACT TO
TRAVEL EXPECTED THOUGH. BEST CHANCE OVER THE NORTHERN TIER. WEAK
TROUGH WORKS THROUGH THURSDAY NIGHT INTO FRIDAY. COULD SEE SOME SNOW
SHOWERS ACROSS KEWEENAW IN WNW FLOW ON FRIDAY. WEEKEND WILL FEATURE
MODEST WARMING TREND WITH SOME AREAS SLIGHTLY ABOVE FREEZING FOR
DAYTIME HIGHS. LGT SNOW MAY ACCOMPANY THIS WARM AIR ADVECTION BUT
LOOKS LIKE BETTER CHANCE FOR ANY SNOW ACCUMULATION WILL REMAIN TO
NORTH OF CWA.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY MORNING) ISSUED AT
520 AM EST MON NOV 25 2013
A GUSTY SW WIND APRCHG 30 KTS AT IWD WL ADVECT LLVL DRY AIR INTO UPR
MI EARLY THIS MRNG...SO EXPECT VFR CONDITIONS DESPITE QUITE A BIT OF
MID CLD COVER. BUT AS A STRONG DISTURBANCE NOW NEAR LK WINNIPEG AND
ITS ATTENDANT SFC COLD FNT DIG SEWD TOWARD THE UPR LKS...EXPECT MVFR
CONDITIONS TO DVLP OVER THE W AT IWD AND CMX BY SUNRISE. WITH A
STRONG UPSLOPE W WIND...THE FROPA WL BRING IFR CONDITIONS FOR A
COUPLE HRS AT CMX DURING THE MRNG. ALTHOUGH SOME MVFR CIGS MAY OCCUR
AT SAW WITH THE FROPA...DOWNSLOPE NATURE OF THE FLOW INDICATES THIS
CONDITION WL BE MARGINAL AND MAY REMAIN VFR. THE BEST CHC OF MORE
PERSISTENT MVFR WX ON MON WL BE AT CMX WITH A MORE PRONOUNCED
UPSLOPE W WIND...WHICH WL GUST AS HI AS 30 KTS AT THIS EXPOSED
LOCATION WITH A SLOW INFLUX OF COLDER AIR/MORE DESTABILIZATION. THE
APRCH OF ANOTHER DISTURBANCE/LO PRES TROF MAY BRING ANOTHER ROUND OF
HEAVIER LES TO CMX THIS EVNG...SO FCST IFR VSBYS AT THIS SITE THEN.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 252 PM EST SUN NOV 24 2013
SW GALES EXPECTED OVER NORTH CENTRAL LAKE SUPERIOR AND THE NORTHERN
LAKE MICHIGAN ZONES TONIGHT INTO MON MORNING AND WILL CONTINUE THE
GALE WARNING IN LAKE SUPERIOR DUE TO CHANNELED FLOW BETWEEN THE
KEWEENAW AND ISLE ROYALE. WINDS TURN TO NORTHWEST ON MONDAY INTO
TUESDAY AND REMAIN UP TO 30 KTS. GETS CLOSE TO GALES ON LAKE
SUPERIOR AGAIN TUE NIGHT INTO WED AND WILL HAVE TO WATCH THIS EVENT
FOR NOW. WINDS THEN STAY BELOW 20 KNOTS FOR THE REST OF THE FORECAST
PERIOD.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY FROM 10 PM THIS EVENING TO 7 AM EST
WEDNESDAY FOR MIZ001-003.
WIND ADVISORY UNTIL 10 AM EST THIS MORNING FOR MIZ013-014.
LAKE EFFECT SNOW ADVISORY FROM 10 PM EST /9 PM CST/ THIS EVENING
TO NOON EST /11 AM CST/ WEDNESDAY FOR MIZ002-009.
LAKE SUPERIOR...
GALE WARNING UNTIL 2 PM EST THIS AFTERNOON FOR LSZ266-267.
GALE WARNING UNTIL 11 AM EST THIS MORNING FOR LSZ263-264.
LAKE MICHIGAN...
GALE WARNING UNTIL NOON EST TODAY FOR LMZ248-250.
GALE WARNING UNTIL 7 AM EST THIS MORNING FOR LMZ221.
&&
$$
SHORT TERM...JLB
LONG TERM...JLA
AVIATION...KC
MARINE...07
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
517 AM EST MON NOV 25 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 516 AM EST MON NOV 25 2013
WV IMAGERY AND RUC ANALYSIS INDICATED WNW MID/UPPER LEVEL FLOW FROM
CNTRL CANADA THROUGH THE GREAT LAKES WITH ONE SHORTWAVE TROUGH FROM
NW ONTARIO INTO NW MN AND ANOTHER WELL TO THE NORTH MOVING INTO NRN
SASK. AT THE SFC...A TIGHT PRES GRADIENT PREVAILED ACROSS THE WRN
GREAT LAKES BTWN A 1000 MB LOW LOCATED JUST NORTH OF THUNDER BAY
ONTARIO AND A 1036 MB RIDGE OVER THE OH VALLEY. WITH THE STRONGEST
PRES FALLS MOVING TO THE NE OF LAKE SUPERIOR...VERY STRONG SW WINDS
PERSISTED ACROSS WRN LAKE SUPERIOR AND NRN LAKE MICHIGAN. WAA
LEADING TO INCREASING STABILITY HAS LIMITED MIXING OF 45-50 KNOT
925-850 MB WINDS TOWARD THE SFC EXCEPT OVER THE RELATIVELY WARM LAKE
MICHIGAN WATERS. GUSTS IN THE 35-40 KT RANGE PERSISTED FROM FAIRPORT
TO PORT INLAND WHERE A WIND ADVISORY WAS IN EFFECT. WINDS OVER
INLAND LOCATIONS AT ESC AND ISQ WERE ONLY GUSTING TO AROUND 25
KNOTS. RADAR INDICATED WEAK RETURNS...MAINLY OVER THE ERN CWA...WITH
SOME PATCHY LIGHT SNOW OR FLURRIES SUPPORTED BY 700-300 QVECTOR CONV
AND ISENTROPIC LIFT AHEAD OF THE UPSTREAM SHRTWV.
TODAY...EXPECT WINDS TO SUBSIDE BY THE 15Z WIND ADVISORY EXPIRATION
TIME AS THE CORE OF THE STRONGEST 925-850 MB WINDS SHIFTS OFF TO THE
EAST. AS THE AREA OF LIGHT SNOW MOVES TO THE EAST...SOME LAKE
ENHANCEMENT MAY BE POSSIBLE WITH THE SW FLOW OFF OF LAKE MICHIGAN
BUT SHOULD REMAIN MAINLY TO THE SOUTH AND EAST OF THE CWA. OVER THE
KEWEENAW...AN AREA OF LOW LEVEL CONV AS WINDS VEER FROM SW TO W MAY
BRING A BRIEF PERIOD OF LAKE ENHANCED SNOW. HOWEVER...MID LEVEL
DRYING WITH THE DRY SLOT AND MARGINAL INSTABILITY WITH 850 MB TEMPS
AROUND -7C (LAKE SFC NEAR 4C) SUPPORTS ONLY CHANCE POPS WITH ANY
ACCUMULATIONS ONLY AMOUNTING TO A HALF INCH OR LESS. INCREASING
850-700 MB MOISTURE AND AND 850/700 MB TEMPS DROPPING TO -10C/-17C
WITH THE APPROACH OF THE SHRTWV WILL ALSO BRING AN INCREASE IN LAKE
ENHANCED SNOW INTO THE WEST AND THE ERN SHORELINE FROM PICTURED
ROCKS TO GRAND MARAIS.
TONIGHT...STRONGER CAA DROPPING 850 MB TEMPS TO AROUND -18C BOOSTING
LAKE INDUCED CAPES TO NEAR 700 J/KG ALONG WITH STRENGTHENING
CYCLONIC NW FLOW WILL BRING A FURTHER INCREASE IN LES INTO THE WEST.
THE HIGH RES MODELS OFFER A VARIETY OF SOLUTIONS AS TO WHERE THE
HEAVIER SNOW BANDS WILL FOCUS AND DELAY THE STRONGER VEERING WIND
SHIFT AND LOW LEVEL CONV BAND MOVING IN TIL AFT 12Z. ALTHOUGH
SEVERAL INDICATE THE GREATER SNOW POTENTIAL INTO THE KEWEENAW AND
IRONWOOD AREAS...CONFIDENCE IN IN HIGHLIGHTING ANY PARTICULAR
LOCATION IS LIMITED. SO...A GENERAL 2 TO 5 INCH FCST WAS INCLUDED
FOR MOST OF THE NW TO WNW FLOW SNOWBELTS IN THE WEST AS WELL AS
LOCATIONS NORTH OF M-28 EAST OF MUNISING.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 437 AM EST MON NOV 25 2013
EXTENT OF LAKE EFFECT SNOW AND SNOW AMOUNTS ALONG WITH THE NEED FOR
ANY ADVISORIES OR WARNINGS TUESDAY/TUESDAY NIGHT IS PRIMARY FOCUS.
IN LARGE SCALE...STRONG SHORTWAVE IN NORTHERN STREAM CURRENTLY OVER
NORTHERN MANTIOBA WILL BE CROSSING UPR MICHIGAN AND LK SUPERIOR ON
TUESDAY. NAM/GFS/ECMWF DECENT AGREEMENT WITH TIMING OF LARGER SCALE
IMPACTS AS THEY ALL SHOW H7-H5/H5-H3 Q-VECTOR CONVERGENCE INTO WESTERN
UPR MICHIGAN BEFORE 12Z TUESDAY SPREADING TO CNTRL CWA BY 18Z AND
EXITING EASTERN CWA BY 00Z WEDNESDAY. MAY SEE MINOR LGT SNOW EVEN
INTO SOUTH AS THE SHORTWAVE CROSSES THE REGION. BIGGEST IMPACT
THOUGH WILL BE ON LK EFFECT THAT BEGINS LATE TONIGHT. NAM AND GFS
FORECAST SOUNDINGS SHOW GOOD RESPONSE FM THE WAVE WITH INVERSION
HEIGHTS RISING ABOVE 5KFT LATE TONIGHT AND SPIKING UP TO 8-10KFT BY
MIDDAY TUESDAY. LAKE EQUILIBRIUM LEVELS INCREASE TO 13KFT AND LAKE
INDUCED CAPE VALUES CLIMB OVER 700J/KG AS H85 TEMPS FALL TO -17C TO
-20C BY TUESDAY NIGHT. SOUNDINGS ALSO INDICATE INCREASING MOISTURE
QUALITY TUESDAY INTO MOST OF TUESDAY NIGHT. SO...INSTABILITY AND
MOISTURE NOT THE ISSUE FOR MODERATE TO HEAVY SNOW. BOTH PARAMETERS
ARE THERE NO DOUBT. MAIN STICKING POINT FOR THE FORECAST ARE
LOW-LEVEL WIND FIELDS AND MORE SPECIFICALLY THE WIND DIRECTION WHICH
IS ALL SO CRITICAL FOR PEGGING WHERE HEAVIEST LK EFFECT WILL OCCUR.
UNFORTUNATELY...NOTEABLE DIFFERENCES EXIST BTWN THE NAM/NCEP HIGH
RES RUNS AND THE COARSER ECMWF/GFS AND ALSO THE GEM. MAIN ISSUE IS
HOW QUICKLY SOUTH TO BRING LOW-LEVEL WIND SHIFT PASSAGE ON TUESDAY.
PASSAGE OF THE TROUGH ESSENTIALLY KICKS LK EFFECT FM WNW/NW FLOW
AREAS TO AREAS FAVORED BY N/NNE WINDS. USUALLY LIKE THE NAM WITH
HIGHER RESOLUTION DETAILS...BUT SUCH A QUICK TROUGH PASSAGE AT
15Z-18Z ON TUESDAY IN THE NORTH SEEMS QUESTIONABLE AS SHORTWAVE
TROUGH AXIS IS STILL OVER CNTRL UPR MICHIGAN AT 18Z. WOULD EXPECT
THE TROUGH PASSAGE TO OCCUR TUESDAY EVENING IN THE WAKE OF THE
SHORTWAVE TROUGH CROSSING THE AREA. OVERALL...PREFERRED SOLUTION
IS PROBABLY MOST CLOSEST TO GFS/LOCAL REGIONAL WRF AND ECMWF.
WHAT THIS MEANS IN TERMS OF LK EFFECT SNOW IS EXPECT A PROLONGED
PERIOD OF LK EFFECT FOR WNW/NW FLOW AREAS LATE TONIGHT THROUGH LATE
TUESDAY AFTN /WHITE PINE TO ROCKLAND/TWIN LAKES AND MAYBE AS FAR
NORTH AS HOUGHTON/ AND ALSO OVER NORTHERN PARTS OF ALGER AND LUCE
COUNTIES. HEAVIER LK EFFECT THEN SHIFTS TO GOGEBIC/WESTERN ONTONAGON
AND MARQUETTE COUNTIES BY TUESDAY EVENING. BASED ON EXPECTED SLR/S
NEARING 20:1 OR EVEN ABOVE 20:1 AND QPF WHICH WAS BLEND OF REGIONAL
WRF AND EVENTUALLY THE WETTER NAM DNG LATER TUESDAY...SEEMS LIKE A
SOLID ADVY EVENT IS IN STORE WITH SNOW AMOUNTS OF 4-6/5-8 INCHES IN
THE 12 HOUR PERIOD FOR TUESDAY AND AGAIN ON TUESDAY NIGHT...THOUGH
THE LOCATIONS OF HEAVIEST SNOW SHOULD SHIFT AROUND AS WINDS IN THE
LAKE CONVECTIVE LAYER SO SOME SHEAR AND DO NOT STAY LOCKED IN THE
SAME DIRECTION FOR VERY LONG PERIOD OF TIME. SOME LOCATIONS IN THE
FAR WESTERN CWA /VCNTY OF IWD TO BERGLAND AND WHITE PINE/ MAY COME
CLOSER TO WARNING CRITERIA TUESDAY AFTN INTO TUESDAY NIGHT BUT SINCE
THE LARGER SCALE FORCING IS DIMINISHING WHEN WIND DIRECTION BECOMES
A MORE FAVORABLE N-NNE TO INCREASE CONVERGENCE IN THESE AREAS...WILL
OPT TO ISSUE THE ADVY AND LET FUTURE SHIFTS UPGRADE TO WARNING IF IT
IS NEEDED. SNOW WILL BE THE MAIN ISSUE WITH THIS EVENT. WINDS WILL
BE GUSTY 25-35 MPH...BUT STRONGEST WINDS AND BLSN/VSBY IMPACTS WILL
BE MORE OVER THE NORTHERN PARTS OF THE KEWEENAW ON TUESDAY AND
PERHAPS INTO NCNTRL UPR MICHIGAN ON TUESDAY NIGHT. NOT EXPECTING
WIDESPREAD BLSN AS THE EVENT THIS LAST WEEKEND HAD.
FOR NOW...COORDINATED WITH SHORT TERM FORECASTER AND PUT OUT LAKE
EFFECT SNOW ADVISORIES FOR WESTERN TIER. ADDITIONAL HEADLINES WILL
LIKELY BE ISSUED OVER NCNTRL AND POSSIBLY NORTHEAST CWA LATER TODAY
OR TONIGHT...BUT SINCE THE MORE SIGNIFICANT SNOW WILL NOT OCCUR IN
THESE AREAS UNTIL LATER TUESDAY OR EVEN AS LATE AS TUESDAY NIGHT IF
GFS IS COMPLETELY CORRECT...WILL NOT ISSUE THOSE HEADLINES NOW. NOT
ENOUGH CONFIDENCE THAT THESE AREAS WOULD SEE WARNING AMOUNTS SO DID
NOT WANT TO PUT A WATCH OUT EITHER.
SNOW SHOWERS PERSIST FOR N FLOW AREAS ON WEDNESDAY...BUT INTENSITY
WILL BE ON THE WANE WITH LOWERING INVERSION HEIGHTS TO AT OR BLO
5KFT. EVEN AS SNOW DIMINISHES...THE DGZ WILL BE IN THE HEART OF THE
LAKE CONVECTIVE LAYER SO WHAT SNOW SHOWERS ARE LEFTOVER ON WEDNESDAY
WILL BE THE EFFECIENT FLUFFY TYPE. WINDS WILL BE ON THE DECREASE AS
WELL...AS WILL BLSN/ASSOCIATED VSBY ISSUES. SINCE THE FLOW REMAINS
LGT NORTH ALL DAY AND INSTABILITY IS MORE THAN SUFFICIENT...SNOW
SHOWERS PROBABLY WILL NOT END COMPLETELY FOR FAR WEST OR NCNTRL BUT
THEY MAY BECOME PINNED CLOSER TO THE SHORELINES ON WEDNESDAY NIGHT
AS MESOSCALE EFFECTS/LAND BREEZES START TO DRIVE THE LOW-LEVEL
CONVERGENCE.
STILL COULD SEE SOME LGT SNOW ON THANKSGIVING. NO BIG IMPACT TO
TRAVEL EXPECTED THOUGH. BEST CHANCE OVER THE NORTHERN TIER. WEAK
TROUGH WORKS THROUGH THURSDAY NIGHT INTO FRIDAY. COULD SEE SOME SNOW
SHOWERS ACROSS KEWEENAW IN WNW FLOW ON FRIDAY. WEEKEND WILL FEATURE
MODEST WARMING TREND WITH SOME AREAS SLIGHTLY ABOVE FREEZING FOR
DAYTIME HIGHS. LGT SNOW MAY ACCOMPANY THIS WARM AIR ADVECTION BUT
LOOKS LIKE BETTER CHANCE FOR ANY SNOW ACCUMULATION WILL REMAIN TO
NORTH OF CWA.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 628 PM EST SUN NOV 24 2013
A GUSTY SW WIND APRCHG 30 KTS AT IWD WL ADVECT LLVL DRY AIR INTO UPR
MI INTO THE EARLY MRNG HRS ON MON...SO EXPECT VFR CONDITIONS DESPITE
QUITE A BIT OF MID CLD COVER. BUT AS A STRONG DISTURBANCE NOW NEAR
LK WINNIPEG AND ITS ATTENDANT SFC COLD FNT DIG SEWD TOWARD THE UPR
LKS...EXPECT MVFR CONDITIONS TO DVLP OVER THE W AT IWD AND CMX BY
SUNRISE. WITH A STRONG UPSLOPE W WIND...THE FROPA WL BRING IFR
CONDITIONS FOR A COUPLE HRS AT CMX DURING THE MRNG. ALTHOUGH SOME
MVFR CIGS MAY OCCUR AT SAW WITH THE FROPA...DOWNSLOPE NATURE OF THE
FLOW INDICATES THIS CONDITION WL BE MARGINAL. THE BEST CHC OF MORE
PERSISTENT MVFR WX ON MON WL BE AT CMX WITH A MORE PRONOUNCED
UPSLOPE W WIND...WHICH WL GUST AS HI AS 30 KTS AT THIS EXPOSED
LOCATION WITH A SLOW INFLUX OF COLDER AIR/DESTABILIZATION.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 252 PM EST SUN NOV 24 2013
SW GALES EXPECTED OVER NORTH CENTRAL LAKE SUPERIOR AND THE NORTHERN
LAKE MICHIGAN ZONES TONIGHT INTO MON MORNING AND WILL CONTINUE THE
GALE WARNING IN LAKE SUPERIOR DUE TO CHANNELED FLOW BETWEEN THE
KEWEENAW AND ISLE ROYALE. WINDS TURN TO NORTHWEST ON MONDAY INTO
TUESDAY AND REMAIN UP TO 30 KTS. GETS CLOSE TO GALES ON LAKE
SUPERIOR AGAIN TUE NIGHT INTO WED AND WILL HAVE TO WATCH THIS EVENT
FOR NOW. WINDS THEN STAY BELOW 20 KNOTS FOR THE REST OF THE FORECAST
PERIOD.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY FROM 10 PM THIS EVENING TO 7 AM EST
WEDNESDAY FOR MIZ001-003.
WIND ADVISORY UNTIL 10 AM EST THIS MORNING FOR MIZ013-014.
LAKE EFFECT SNOW ADVISORY FROM 10 PM EST /9 PM CST/ THIS EVENING
TO NOON EST /11 AM CST/ WEDNESDAY FOR MIZ002-009.
LAKE SUPERIOR...
GALE WARNING UNTIL 2 PM EST THIS AFTERNOON FOR LSZ266-267.
GALE WARNING UNTIL 11 AM EST THIS MORNING FOR LSZ263-264.
LAKE MICHIGAN...
GALE WARNING UNTIL NOON EST TODAY FOR LMZ248-250.
GALE WARNING UNTIL 7 AM EST THIS MORNING FOR LMZ221.
&&
$$
SHORT TERM...JLB
LONG TERM...JLA
AVIATION...KC
MARINE...07
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
522 AM CST MON NOV 25 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 327 AM CST MON NOV 25 2013
A WEAK COLD FRONT CURRENTLY MOVING THROUGH SRN SOUTH DAKOTA
SHOULD CLEAR THE FORECAST AREA BY 21Z. A STRONG THERMAL RIDGE IS
RUNNING OUT AHEAD OF THE COLD FRONT WITH SFC TEMPS RISING INTO THE
UPPER 30S. THIS SHOULD MIX OUT THE ATMOSPHERE AND GIVE A HEAD
START TO MAX TEMPS IN THE 40S. THIS IS CLOSE TO THE RAP MODEL
WHICH WAS THE WARMEST SOLN NEXT TO THE ECM GUIDANCE FORECASTING
HIGHS IN THE MID AND UPPER 40S. SOME MID LEVEL CLOUDINESS
ASSOCIATED WITH THE COLD FRONT WOULD SUGGEST USING A FCST SLIGHTLY
COOLER THAN THE VERY WARM ECM GUIDANCE.
FOR TONIGHT...A REINFORCING ARCTIC FRONT...CURRENTLY ACROSS NRN
SASKATCHEWAN WILL BE MOVING THROUGH SD WITH A WEAK THERMAL RIDGE
RUNNING OUT AHEAD OF THIS FRONT. THE MODEL CONSENSUS SUGGESTED LOWS
IN THE TEENS WHICH MIGHT BE TOO COLD. THE MODELS APPEAR TO BE
PUSHING THIS FRONT INTO THE FCST AREA AROUND 06Z TONIGHT WITH H850
MB WINDS INCREASING TO 35 TO 40 KT WHICH WOULD SUPPORT MIXING
AND WARMER LOWS.
NO STRATUS IS EXPECTED WITH EITHER FRONT TODAY OR TONIGHT.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 327 AM CST MON NOV 25 2013
THE SOUTHERN PLAINS UPPER LEVEL LOW WILL PHASE TUESDAY WITH A
STRONG SHORTWAVE DROPPING SOUTHEAST THROUGH CANADA INTO THE GREAT
LAKES REGION. THIS WILL BRING HEAVY PRECIPITATION TO THE EAST
COAST WEDNESDAY. ACROSS OUR AREA...ANOTHER SHOT OF ARCTIC AIR
WILL PLUMMET SOUTH TUESDAY ON THE BACK SIDE OF THE DEVELOPING
EASTERN CONUS STORM. THIS WILL KEEP HIGHS IN THE 20S ONCE AGAIN
ACROSS PORTIONS OF NORTHERN NEBRASKA...WITH LOWER TO MID 30S
ACROSS THE PANHANDLE INTO SOUTHWEST NEBRASKA. THIS COLD AIR WILL
BE SHORT LIVED...AS UPPER LEVEL RIDGING AND A PACIFIC AIRMASS
SPREAD EAST THROUGH THE PLAINS STARTING WEDNESDAY. THE ECMWF HAS
BEEN ADVERTISING A CHINOOK EVENT WEDNESDAY...AND THIS SHOULD HELP
SCOUR OUT THE ARCTIC AIR. SHOULD SEE HIGHS INTO THE 40S ACROSS
WESTERN NEBRASKA...WITH LOWER 30S FARTHER EAST WHERE THE ARCTIC
AIR WILL BE MORE DENSE AND TAKE LONGER TO MIX OUT.
THE UPPER RIDGE BECOMES DOMINATE THANKSGIVING AND FRIDAY...WITH
DRY AND MILD CONDITIONS AREA WIDE. BY THE WEEKEND...THE UPPER
RIDGE WILL BEGIN TO FLATTEN...BUT IT REMAINS MILD AND DRY. MORE
COLD ARCTIC AIR IS POSSIBLE BEYOND THE FORECAST PERIOD AS WE HEAD
INTO NEXT WEEK...AS LARGE GULF OF ALASKA UPPER LEVEL LOW COULD
DROP SOUTHEAST INTO THE PACIFIC NORTHWEST. STAY TUNED.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 522 AM CST MON NOV 25 2013
VFR IS EXPECTED TODAY AND TONIGHT. IFR/MVFR ACROSS SCNTL NEB WILL
MOVE EAST THIS MORNING...AWAY FROM THE FCST AREA. A WEAK COLD
FRONT WILL MOVE THROUGH THE FCST AREA THIS MORNING FOLLOWED BY A
SECOND STRONGER FRONT LATE TONIGHT. VFR CIGS ARE EXPECTED TO
PREVAIL WITH BOTH FRONTAL PASSAGES.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CDC
LONG TERM...TAYLOR
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
613 AM CST MON NOV 25 2013
UPDATED AVIATION PORTION FOR 12Z TAF ISSUANCE
.SHORT TERM...TODAY...TONIGHT...AND TUESDAY
ISSUED AT 406 AM CST MON NOV 25 2013
PRIMARY FOCUS OF SHORT-TERM FORECAST WILL BE LIGHT PRECIPITATION
ASSOCIATED WITH A COUPLE RATHER POTENT NORTHERN STREAM SHORTWAVE
DISTURBANCES DIVING SOUTHEAST ACROSS THE WESTERN GREAT LAKES...AND
INCREASING LES POTENTIAL ACROSS THE LAKE SUPERIOR SNOWBELT.
WATER VAPOR IMAGERY SHOWS FIRST SHORTWAVE DISTURBANCE HEADING
SOUTHEAST TOWARD LAKE SUPERIOR EARLY THIS MORNING. PRIMARY
SYNOPTIC FORCING WITH THIS FEATURE TO REMAIN NORTH OF THE FORECAST
AREA TODAY. FORCING RATHER LACKLUSTER FURTHER SOUTH ASSOCIATED
WITH WEAK SURFACE TROUGH HEADING SOUTHEAST ACROSS MINNESOTA. 00Z
SOUNDINGS AT MPX...GRB AND ILX ONCE AGAIN SUGGEST RATHER PALTRY
DEEP LAYER MOISTURE TO WORK WITH AHEAD OF THIS SYSTEM. THUS AS
INDICATED IN LATEST RADAR DATA...HAVE ONLY BEEN ABLE TO GENERATE
BAND OF VERY WEAK RADAR RETURNS EXTENDING FROM NORTHCENTRAL
WISCONSIN TO SOUTHWEST MINNESOTA. LITTLE OR NO PRECIPITATION
ASSOCIATED WITH THIS FEATURE THUS FAR WITH JUST FLURRIES BEING
REPORTED.
MEANWHILE FURTHER SOUTH...WHERE ANOTHER VERY WEAK IMPULSE...WEAK
FRONTOGENETIC FORCING AND SLIGHTLY DEEPER MOISTURE EXIST...SCATTERED
TO BROKEN SNOW SHOWER ACTIVITY HAS BROKEN OUT OVER EASTERN IOWA.
SHORT RANGE MODEL GUIDANCE SUGGEST THAT THIS ACTIVITY WILL MOVE
ENE AND AFFECT MAINLY THE SOUTHERN THIRD OF THE FORECAST AREA THIS
MORNING. BASED ON LATEST OBSERVATIONS APPEARS MOISTURE IS DEEP
ENOUGH TO GENERATE ICE CRYSTALS RESULTING IN MAINLY SNOW RATHER
THAN FREEZING DRIZZLE. GIVEN THE POORLY ORGANIZED AND WEAK
FORCING...AND UNCERTAINTY IN AVAILABLE MOISTURE OVER THE FORECAST
AREA THIS MORNING...OPTED TO KEEP A MIX OF VERY LIGHT SNOW AND/OR
FREEZING DRIZZLE GOING FOR THE ENTIRE FORECAST AREA THROUGH ABOUT
17Z. GIVEN LATEST RADAR TRENDS AND HRRR FORECAST...APPEARS BEST
CHANCE FOR LIGHT MEASURABLE PRECIPITATION WILL BE OVER THE FOX
VALLEY THIS MORNING...THUS KEPT HIGHEST POPS THERE. WILL CONTINUE TO
MONITOR RADAR TRENDS AND SURFACE OBSERVATIONS ACROSS THIS AREA AS
THERE STILL IS POTENTIAL FOR SUFFICIENT LIGHT SNOW OR LIGHT FREEZING
DRIZZLE TO CREATE A FEW SLICK SPOTS DURING THE MORNING COMMUTE. IF
THIS DOES OCCUR...WILL HANDLE WITH SPS.
GUIDANCE ALSO SUGGESTS THAT SURFACE PRESSURE GRADIENT WILL BE
STRONGEST BETWEEN NOW AND ABOUT 15Z...AND WILL BEGIN TO RELAX
THEREAFTER AS SURFACE TROUGH SWINGS THROUGH THE AREA AROUND
MIDDAY. THUS EXPECT RATHER STRONG SOUTHWEST WINDS TO CONTINUE TO
GUST INTO THE 30-35 MPG RANGE THROUGH MID-MORNING AND DIMINISH
SOMEWHAT THEREAFTER.
NEXT AND SOMEWHAT MORE POTENT SHORTWAVE THEN IMPINGES ON THE
FORECAST AREA TOWARD DAYBREAK TUESDAY. FEEL LARGE-SCALE FORCING
WILL BE A BIT MORE ROBUST SUCH THAT MAY SEE MORE WIDESPREAD SNOW
SHOWER ACTIVITY ESPECIALLY ACROSS NORTHCENTRAL WISCONSIN TUESDAY.
MORE IMPORTANTLY...AS THIS SYSTEM MOVES ACROSS NORTHERN WISCONSIN
TUESDAY MORNING...BOUNDARY LAYER WINDS WILL VEER TO FAVORABLE 340
DEGREE DIRECTION OVER WESTERN LAKE SUPERIOR TO INITIATE LES BANDS
ONCE AGAIN. GIVEN RATHER IMPRESSIVE SHORTWAVE PASSING THROUGH THIS
AREA...FAVORABLE FETCH AND OVER WATER INSTABILITY...ACCUMULATING
SNOWS SEEM LIKELY ACROSS NORTHWEST VILAS COUNTY STARTING AROUND
18Z TUESDAY AND CONTINUING INTO TUESDAY NIGHT. HOWEVER MODELS DO
SUGGEST BOUNDARY LAYER WINDS WILL VEER TO A LESS FAVORABLE 360
DEGREES BY 06Z WEDNESDAY. WILL LET DAY-SHIFT TAKE A CLOSER LOOK AT
THE LES POTENTIAL FOR LATER TUESDAY INTO TUESDAY NIGHT...BUT WOULD
NOT BE SURPRISED TO SEE ADVISORY HOISTED AT SOME POINT.
.LONG TERM...TUESDAY NIGHT THROUGH SUNDAY
ISSUED AT 406 AM CST MON NOV 25 2013
UPPER LEVEL FLOW ACROSS THE NORTHERN CONUS IS FORECAST TO BECOME
LESS AMPLIFIED/MORE ZONAL BY THE END OF THE WEEK. THIS WILL RESULT
IN THE THERMAL TROUGH...THAT SHOULD BE OVER THE AREA TUESDAY
NIGHT...SHIFTING EAST OF WISCONSIN. WARM ADVECTION LATER DURING
THE WEEK WILL BRING NEAR NORMAL HIGH TEMPERATURES BY THE WEEKEND.
LAKE EFFECT SHOULD COME TO AN END IN THE FORECAST AREA BY
WEDNESDAY AFTERNOON AS A SURFACE RIDGE REACHES THE STATE. SNOW
WITH THE NEXT CLIPPER SYSTEM SHOULD REMAIN NORTH OF THE STATE...SO
ONLY SOME SLIGHT CHANCES FOR SNOW IN THE FAR NORTH ON THURSDAY.
THE NEXT SYSTEM AFTER THAT IS EXPECTED TO PUSH FARTHER SOUTH AND
BRING A CHANCE FOR SNOW SHOWERS TO NORTHERN WISCONSIN ON SATURDAY.
LITTLE MOISTURE WILL ACCOMPANY THESE SYSTEMS SO ANY ACCUMULATION
SHOULD BE MINOR.
&&
.AVIATION...FOR 12Z TAF ISSUANCE
ISSUED AT 611 AM CST MON NOV 25 2013
AN UPPER-LEVEL DISTURBANCE AND ASSOCIATED SURFACE TROUGH WILL
GENERATE A BRIEF PERIOD OF LIGHT SNOW POSSIBLY MIXED WITH SOME
LIGHT FREEZING DRIZZLE THROUGH ABOUT 14Z AT GRB AND ATW TAF SITES.
MAINLY MVFR CIGS AND VSBYS EXPECTED IN THE HEAVIER SNOW SHOWERS.
PRECIPITATION SHOULD EXIT THE FOX VALLEY BY 15Z...AND WILL BE
FOLLOWED BY AREAS OF MVFR CIGS THROUGH ABOUT 20Z. STRONG SOUTHWEST
WINDS GUSTING TO 30KTS AND LLWS SHOULD DIMINISH AFTER 15Z AS PRESSURE
GRADIENT RELAXES WITH APPROACHING SURFACE TROUGH. GENERALLY VFR
CONDITIONS OVERNIGHT...EXCEPT ACROSS NORTHERN WISCONSIN WHERE MVFR
CIGS AND VSBYS ARE POSSIBLE AS ANOTHER UPPER-LEVEL DISTURBANCE
APPROACHES IN CONCERT WITH INCREASING LAKE EFFECT SNOW BANDS OFF
LAKE SUPERIOR. THE SNOW SHOWER ACTIVITY WILL BE MOST NUMEROUS OVER
VILAS COUNTY AFTER MIDNIGHT.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....ESB
LONG TERM......MG
AVIATION.......ESB
FORECAST DISCUSSION FOR ROUTINE MORNING FORECAST ISSUANCE
.SHORT TERM...TODAY...TONIGHT...AND TUESDAY
ISSUED AT 406 AM CST MON NOV 25 2013
PRIMARY FOCUS OF SHORT-TERM FORECAST WILL BE LIGHT PRECIPITATION
ASSOCIATED WITH A COUPLE RATHER POTENT NORTHERN STREAM SHORTWAVE
DISTURBANCES DIVING SOUTHEAST ACROSS THE WESTERN GREAT LAKES...AND
INCREASING LES POTENTIAL ACROSS THE LAKE SUPERIOR SNOWBELT.
WATER VAPOR IMAGERY SHOWS FIRST SHORTWAVE DISTURBANCE HEADING
SOUTHEAST TOWARD LAKE SUPERIOR EARLY THIS MORNING. PRIMARY
SYNOPTIC FORCING WITH THIS FEATURE TO REMAIN NORTH OF THE FORECAST
AREA TODAY. FORCING RATHER LACKLUSTER FURTHER SOUTH ASSOCIATED
WITH WEAK SURFACE TROUGH HEADING SOUTHEAST ACROSS MINNESOTA. 00Z
SOUNDINGS AT MPX...GRB AND ILX ONCE AGAIN SUGGEST RATHER PALTRY
DEEP LAYER MOISTURE TO WORK WITH AHEAD OF THIS SYSTEM. THUS AS
INDICATED IN LATEST RADAR DATA...HAVE ONLY BEEN ABLE TO GENERATE
BAND OF VERY WEAK RADAR RETURNS EXTENDING FROM NORTHCENTRAL
WISCONSIN TO SOUTHWEST MINNESOTA. LITTLE OR NO PRECIPITATION
ASSOCIATED WITH THIS FEATURE THUS FAR WITH JUST FLURRIES BEING
REPORTED.
MEANWHILE FURTHER SOUTH...WHERE ANOTHER VERY WEAK IMPULSE...WEAK
FRONTOGENETIC FORCING AND SLIGHTLY DEEPER MOISTURE EXIST...SCATTERED
TO BROKEN SNOW SHOWER ACTIVITY HAS BROKEN OUT OVER EASTERN IOWA.
SHORT RANGE MODEL GUIDANCE SUGGEST THAT THIS ACTIVITY WILL MOVE
ENE AND AFFECT MAINLY THE SOUTHERN THIRD OF THE FORECAST AREA THIS
MORNING. BASED ON LATEST OBSERVATIONS APPEARS MOISTURE IS DEEP
ENOUGH TO GENERATE ICE CRYSTALS RESULTING IN MAINLY SNOW RATHER
THAN FREEZING DRIZZLE. GIVEN THE POORLY ORGANIZED AND WEAK
FORCING...AND UNCERTAINTY IN AVAILABLE MOISTURE OVER THE FORECAST
AREA THIS MORNING...OPTED TO KEEP A MIX OF VERY LIGHT SNOW AND/OR
FREEZING DRIZZLE GOING FOR THE ENTIRE FORECAST AREA THROUGH ABOUT
17Z. GIVEN LATEST RADAR TRENDS AND HRRR FORECAST...APPEARS BEST
CHANCE FOR LIGHT MEASURABLE PRECIPITATION WILL BE OVER THE FOX
VALLEY THIS MORNING...THUS KEPT HIGHEST POPS THERE. WILL CONTINUE TO
MONITOR RADAR TRENDS AND SURFACE OBSERVATIONS ACROSS THIS AREA AS
THERE STILL IS POTENTIAL FOR SUFFICIENT LIGHT SNOW OR LIGHT FREEZING
DRIZZLE TO CREATE A FEW SLICK SPOTS DURING THE MORNING COMMUTE. IF
THIS DOES OCCUR...WILL HANDLE WITH SPS.
GUIDANCE ALSO SUGGESTS THAT SURFACE PRESSURE GRADIENT WILL BE
STRONGEST BETWEEN NOW AND ABOUT 15Z...AND WILL BEGIN TO RELAX
THEREAFTER AS SURFACE TROUGH SWINGS THROUGH THE AREA AROUND
MIDDAY. THUS EXPECT RATHER STRONG SOUTHWEST WINDS TO CONTINUE TO
GUST INTO THE 30-35 MPG RANGE THROUGH MID-MORNING AND DIMINISH
SOMEWHAT THEREAFTER.
NEXT AND SOMEWHAT MORE POTENT SHORTWAVE THEN IMPINGES ON THE
FORECAST AREA TOWARD DAYBREAK TUESDAY. FEEL LARGE-SCALE FORCING
WILL BE A BIT MORE ROBUST SUCH THAT MAY SEE MORE WIDESPREAD SNOW
SHOWER ACTIVITY ESPECIALLY ACROSS NORTHCENTRAL WISCONSIN TUESDAY.
MORE IMPORTANTLY...AS THIS SYSTEM MOVES ACROSS NORTHERN WISCONSIN
TUESDAY MORNING...BOUNDARY LAYER WINDS WILL VEER TO FAVORABLE 340
DEGREE DIRECTION OVER WESTERN LAKE SUPERIOR TO INITIATE LES BANDS
ONCE AGAIN. GIVEN RATHER IMPRESSIVE SHORTWAVE PASSING THROUGH THIS
AREA...FAVORABLE FETCH AND OVER WATER INSTABILITY...ACCUMULATING
SNOWS SEEM LIKELY ACROSS NORTHWEST VILAS COUNTY STARTING AROUND
18Z TUESDAY AND CONTINUING INTO TUESDAY NIGHT. HOWEVER MODELS DO
SUGGEST BOUNDARY LAYER WINDS WILL VEER TO A LESS FAVORABLE 360
DEGREES BY 06Z WEDNESDAY. WILL LET DAY-SHIFT TAKE A CLOSER LOOK AT
THE LES POTENTIAL FOR LATER TUESDAY INTO TUESDAY NIGHT...BUT WOULD
NOT BE SURPRISED TO SEE ADVISORY HOISTED AT SOME POINT.
.LONG TERM...TUESDAY NIGHT THROUGH SUNDAY
ISSUED AT 406 AM CST MON NOV 25 2013
UPPER LEVEL FLOW ACROSS THE NORTHERN CONUS IS FORECAST TO BECOME
LESS AMPLIFIED/MORE ZONAL BY THE END OF THE WEEK. THIS WILL RESULT
IN THE THERMAL TROUGH...THAT SHOULD BE OVER THE AREA TUESDAY
NIGHT...SHIFTING EAST OF WISCONSIN. WARM ADVECTION LATER DURING
THE WEEK WILL BRING NEAR NORMAL HIGH TEMPERATURES BY THE WEEKEND.
LAKE EFFECT SHOULD COME TO AN END IN THE FORECAST AREA BY
WEDNESDAY AFTERNOON AS A SURFACE RIDGE REACHES THE STATE. SNOW
WITH THE NEXT CLIPPER SYSTEM SHOULD REMAIN NORTH OF THE STATE...SO
ONLY SOME SLIGHT CHANCES FOR SNOW IN THE FAR NORTH ON THURSDAY.
THE NEXT SYSTEM AFTER THAT IS EXPECTED TO PUSH FARTHER SOUTH AND
BRING A CHANCE FOR SNOW SHOWERS TO NORTHERN WISCONSIN ON SATURDAY.
LITTLE MOISTURE WILL ACCOMPANY THESE SYSTEMS SO ANY ACCUMULATION
SHOULD BE MINOR.
&&
.AVIATION...FOR 12Z TAF ISSUANCE
ISSUED AT 406 AM CST MON NOV 25 2013
UPPER DISTURBANCE WILL GENERATE SOME VERY LIGHT SNOW OR PERHAPS
SOME LIGHT FREEZING DRIZZLE THIS MORNING. DO NOT EXPECT THIS
PRECIPITATION TO HAVE MUCH IMPACT ON VSBYS. AS WEAK SURFACE
TROUGH PASSES SOUTHEAST ACROSS THE FORECAST AREA TOWARD MID-
DAY...MVFR CIGS WILL FOLLOW. GUSTY SOUTHWEST WINDS AND LLWS SHEAR
WILL DIMINISH LATER THIS MORNING AS PRESSURE GRADIENT RELAXES WITH
APPROACH OF THE SURFACE TROUGH. SCT-BKN MVFR CIGS EXPECTED ON
TUESDAY AS MORE POTENT UPPER DISTURBANCE MOVES ACROSS THE FORECAST
AREA. PERHAPS SOME SCT IFR CIGS AND VSBYS ASSOCIATED WITH HEAVIER
SNOW SHOWER ACTIVITY MAINLY NORTH OF RHI.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....ESB
LONG TERM......MG
AVIATION.......ESB
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
452 PM EST MON NOV 25 2013
.SYNOPSIS...
MOISTURE WILL OVERSPREAD THE FORECAST AREA TONIGHT AHEAD OF LOW
PRESSURE DEVELOPING ALONG THE GULF COAST. THE LOW WILL MOVE
NORTHEAST ACROSS THE OUR AREA TUESDAY AND TUESDAY NIGHT...BRINGING
WIDESPREAD RAIN. THE LOW WILL LIFT NORTHEAST OF THE REGION
WEDNESDAY WITH COLD AND DRY HIGH PRESSURE RETURNING THANKSGIVING
DAY.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
HIGH PRESSURE CENTERED OVER THE MID-ATLANTIC COAST WILL MOVE EAST
AS A WEATHER SYSTEM DEVELOPS ALONG THE GULF COAST OF TEXAS AND
LOUISIANA. LOWER CLOUDS ALREADY ENTERING THE FA FROM THE WEST. STILL
COOL AND DRY CONDITIONS IN THE LOWER LAYERS.
WATER VAPOR IMAGERY AND MSAS ANALYSIS SHOWING A DIFLUENT PATTERN
OVER THE WESTERN GULF OF MEXICO AND LOW PRESSURE IS DEVELOPING
ALONG THE GULF COAST. ALL MODELS INDICATE INCREASING ISENTROPIC
LIFT AHEAD OF THIS LOW WILL RESULT IN PRECIPITATION OVERSPREADING
THE FORECAST AREA FROM SOUTHWEST TO NORTHEAST TONIGHT. THE HRRR
PLUS SATELLITE AND RADAR TRENDS INDICATE THE PRECIPITATION WILL
HOLD OFF UNTIL LATE TONIGHT. THE 1600 GMT HRRR INDICATED AREAS OF
LIGHT PRECIPITATION DEVELOPING IN THE WEST PART OF THE FORECAST
AREA AROUND MIDNIGHT...WITH THE BULK OF THE PRECIPITATION ABOUT TO
MOVE INTO THE WEST PART OF THE AREA AT 200 AM. USED THIS GUIDANCE
FOR THE TIMING.
THE MODELS INDICATE ENOUGH WARMING SHOULD OCCUR FOR ALL LIQUID
PRECIPITATION. ALL SREF MEMBERS KEEP THE SURFACE TEMPERATURE ABOVE
FREEZING LATE TONIGHT...EVEN IN THE NORTH PART. FREEZING RAIN IS
NOT IMPOSSIBLE IN THE EXTREME NORTH SECTION...BUT BELIEVE
PRECIPITATION WILL BE LIGHT AT THE ONSET LIMITING WET-BULB
COOLING. ALSO...THE NAM AND GFS SHOW SURFACE WET-BULB TEMPERATURES
RISING ABOVE FREEZING BEFORE SIGNIFICANT PRECIPITATION REACHES THE
AREA LATE TONIGHT. DESPITE THE MODEL GUIDANCE...THERE MAY BE
LAYERS OF DRY AIR ALOFT WITH WET-BULB COOLING WHICH COULD SUPPORT
SLEET. WE BELIEVE ANY SLEET WOULD BE LIGHT AND WITH SURFACE
TEMPERATURES JUST ABOVE FREEZING...NO ACCUMULATION SHOULD OCCUR.
WE USED THE COOLER TEMPERATURE GUIDANCE TONIGHT BECAUSE OF THE
DRY AIR IN PLACE AND EVAPORATIVE COOLING ASSOCIATED WITH THE
MOISTURE INCREASE.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY/...
TUESDAY THROUGH WEDNESDAY...THE NAM AND GFS INDICATE THE BULK OF
THE RAINFALL WILL OCCUR DURING THE TUESDAY AND TUESDAY NIGHT TIME
FRAME WITH STRONG ISENTROPIC LIFT AND APPROACHING H5 SHORTWAVE
TROUGH. THE NAM...GFS AND SREF MEAN SUPPORT TOTAL RAINFALL FROM
1.5 TO AROUND 2.0 INCHES. THE NAM SHOWS CROSS TOTALS NEAR 25
TUESDAY AND TUESDAY NIGHT...SO A FEW ELEVATED THUNDERSTORMS MAY
OCCUR. THE SURFACE LOW WILL BE NORTHEAST OF THE AREA WITH THE
UPPER TROUGH OVERHEAD WEDNESDAY. WE MAY HAVE LINGERING MORNING
RAIN. STRONG COLD ADVECTION AND DRY AIR WILL POUR INTO THE AREA
WEDNESDAY AFTERNOON.
THE NAM LI-PATTERN INDICATES A WEDGE-TYPE PATTERN TUESDAY. WE
LEANED TOWARD THE IN-HOUSE WEDGE SCHEME FOR THE HIGH TEMPERATURE
FORECAST. EXPECT A NEAR STEADY TEMPERATURE TUESDAY NIGHT. USED
THE COLDER TEMPERATURE GUIDANCE WEDNESDAY BECAUSE OF LINGERING
CLOUDINESS AND A SHARP UPPER TROUGH OVER OUR AREA.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
THE GFS AND ECMWF ARE IN GOOD AGREEMENT SHOWING DRY HIGH PRESSURE
DOMINATING DURING MUCH OF THE THE MEDIUM-RANGE PERIOD. AN ONSHORE
FLOW AND WARM FRONT MAY SUPPORT RAIN MONDAY. BELOW NORMAL
TEMPERATURES SHOULD CONTINUE THROUGH SUNDAY. THE GFS...ECMWF...EKD MOS
PLUS GFS ENSEMBLE MEAN SUPPORT TEMPERATURES AROUND 10 DEGREES
BELOW NORMAL THROUGH SUNDAY WITH NORMAL TEMPERATURES MONDAY.
&&
.AVIATION /22Z MONDAY THROUGH SATURDAY/...
VFR CONDITIONS THROUGH MOST OF TONIGHT THEN DETERIORATING TO IFR
BY 09Z.
HIGH PRESSURE ACROSS THE REGION WILL WEAKEN AND SHIFT INTO THE
ATLANTIC AS LOW PRESSURE ALONG THE NORTHWEST GULF COAST SHIFTS
NORTHEASTWARD. DUE TO MOISTURE FLUX INTO THE AREA AHEAD OF THE
APPROACHING WEATHER SYSTEM...CEILINGS HAVE ALREADY LOWERED TO
AROUND 3500 FT. LIGHT RAIN SHOULD SPREAD INTO THE AREA AROUND 08Z-
09Z AND CONTINUE SPREADING TOWARD THE NORTHEAST AS THE SURFACE LOW
APPROACHES. BY 10Z-12Z...WIDESPREAD RAINFALL IS EXPECTED AND
CONDITIONS SHOULD DETERIORATE RAPIDLY TO IFR. AT THE MORE
NORTHEAST TAF SITES LIKE CAE AND CUB...IFR CONDITIONS MAY BE
DELAYED AS LONG AS 14Z BUT CONDITIONS WILL ALSO DETERIORATE
RAPIDLY AT THOSE LOCATIONS WHEN THE RAIN MOVES IN. MAINLY
MODERATE RAIN ON TUESDAY BUT DUE TO INCREASING ISENTROPIC
LIFT...CANNOT RULE OUT SOME HEAVY RAIN ESPECIALLY AT THE WESTERN
TAF SITES. ALSO WITH INCREASING INSTABILITY ALOFT...A FEW ELEVATED
THUNDERSTORMS ARE POSSIBLE BUT CONFIDENCE WAS TOO LOW TO INCLUDE
IN THIS TAF PACKAGE.
EXTENDED AVIATION OUTLOOK...AN EXTENDED PERIOD OF CIG/VSBY
RESTRICTIONS ARE POSSIBLE TUESDAY AFTERNOON THROUGH WEDNESDAY
NIGHT AS A LOW PRESSURE SYSTEM FROM THE GULF OF MEX CROSSES THE
SOUTHEASTERN STATES.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
420 PM EST MON NOV 25 2013
.SYNOPSIS...
MOISTURE WILL OVERSPREAD THE FORECAST AREA TONIGHT AHEAD OF LOW
PRESSURE DEVELOPING ALONG THE GULF COAST. THE LOW WILL MOVE
NORTHEAST ACROSS THE OUR AREA TUESDAY AND TUESDAY NIGHT...BRINGING
WIDESPREAD RAIN. THE LOW WILL LIFT NORTHEAST OF THE REGION
WEDNESDAY WITH COLD AND DRY HIGH PRESSURE RETURNING THANKSGIVING
DAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
THIS AFTERNOON...HIGH PRESSURE WILL WEAKEN THIS AFTERNOON AS A
WEATHER SYSTEM DEVELOPS IN THE WESTERN GULF COAST STATES OF TEXAS
AND LOUISIANA. THE UPPER RIDGE AXIS OVER THE FA WILL SHIFT EAST
AND ALLOW HIGH AND MID LEVEL CLOUDS TO ENTER THE REGION FROM
THE WEST. STILL COOL AND DRY CONDITIONS IN THE LOWER LAYERS.
AFTERNOON HIGHS MAINLY IN THE MID TO UPPER 40S. A BIT WARMER
IN THE CSRA AND AGS MAY HIT 51 OR 52. LIGHT MAINLY EASTERLY
WINDS ARE EXPECTED. DEWPOINTS IN THE SINGLE DIGITS EARLY THIS
AFTERNOON SHOULD INCREASE TO 10-15 DEGREES BY LATE AFTERNOON
AS MOISTURE BEGINS TO ENTER AREA.
TONIGHT...THE LATEST WATER VAPOR IMAGERY SHOWED A DIFLUENT PATTERN
OVER THE WESTERN GULF OF MEXICO AND LOW PRESSURE IS DEVELOPING
ALONG THE GULF COAST. ALL MODELS INDICATE INCREASING ISENTROPIC
LIFT AHEAD OF THIS LOW WILL RESULT IN PRECIPITATION OVERSPREADING
THE FORECAST AREA FROM SOUTHWEST TO NORTHEAST TONIGHT. THE HRRR
PLUS SATELLITE AND RADAR TRENDS INDICATE THE PRECIPITATION WILL HOLD
OFF UNTIL LATE TONIGHT. THE 1600 GMT HRRR INDICATED AREAS OF LIGHT
PRECIPITATION DEVELOPING IN THE WEST PART OF THE FORECAST AREA
AROUND MIDNIGHT...WITH THE BULK OF THE PRECIPITATION ABOUT TO MOVE
INTO THE WEST PART OF THE AREA AT 200 AM. USED THIS GUIDANCE FOR
THE TIMING.
THE MODELS INDICATE ENOUGH WARMING SHOULD OCCUR FOR ALL LIQUID
PRECIPITATION. ALL SREF MEMBERS KEEP THE SURFACE TEMPERATURE ABOVE
FREEZING LATE TONIGHT...EVEN IN THE NORTH PART. FREEZING RAIN IS
NOT IMPOSSIBLE IN THE EXTREME NORTH SECTION...BUT BELIEVE
PRECIPITATION WILL BE LIGHT AT THE ONSET LIMITING WET-BULB
COOLING. ALSO...THE NAM AND GFS SHOW SURFACE WET-BULB TEMPERATURES
RISING ABOVE FREEZING BEFORE SIGNIFICANT PRECIPITATION REACHES THE
AREA LATE TONIGHT. DESPITE THE MODEL GUIDANCE...THERE MAY BE
LAYERS OF DRY AIR ALOFT WITH WET-BULB COOLING WHICH COULD SUPPORT
SLEET. WE BELIEVE ANY SLEET WOULD BE LIGHT AND WITH SURFACE
TEMPERATURES JUST ABOVE FREEZING...NO ACCUMULATION SHOULD OCCUR.
WE USED THE COOLER TEMPERATURE GUIDANCE TONIGHT BECAUSE OF THE
DRY AIR IN PLACE AND EVAPORATIVE COOLING ASSOCIATED WITH THE
MOISTURE INCREASE.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY/...
TUESDAY THROUGH WEDNESDAY...THE NAM AND GFS INDICATE THE BULK OF
THE RAINFALL WILL OCCUR DURING THE TUESDAY AND TUESDAY NIGHT TIME
FRAME WITH STRONG ISENTROPIC LIFT AND APPROACHING H5 SHORTWAVE
TROUGH. THE NAM...GFS AND SREF MEAN SUPPORT TOTAL RAINFALL FROM
1.5 TO AROUND 2.0 INCHES. THE NAM SHOWS CROSS TOTALS NEAR 25
TUESDAY AND TUESDAY NIGHT...SO A FEW ELEVATED THUNDERSTORMS MAY
OCCUR. THE SURFACE LOW WILL BE NORTHEAST OF THE AREA WITH THE
UPPER TROUGH OVERHEAD WEDNESDAY. WE MAY HAVE LINGERING MORNING
RAIN. STRONG COLD ADVECTION AND DRY AIR WILL POUR INTO THE AREA
WEDNESDAY AFTERNOON.
THE NAM LI-PATTERN INDICATES A WEDGE-TYPE PATTERN TUESDAY. WE
LEANED TOWARD THE IN-HOUSE WEDGE SCHEME FOR THE HIGH TEMPERATURE
FORECAST. EXPECT A NEAR STEADY TEMPERATURE TUESDAY NIGHT. USED
THE COLDER TEMPERATURE GUIDANCE WEDNESDAY BECAUSE OF LINGERING
CLOUDINESS AND A SHARP UPPER TROUGH OVER OUR AREA.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
THE GFS AND ECMWF ARE IN GOOD AGREEMENT SHOWING DRY HIGH PRESSURE
DOMINATING DURING MUCH OF THE THE MEDIUM-RANGE PERIOD. AN ONSHORE
FLOW AND WARM FRONT MAY SUPPORT RAIN MONDAY. BELOW NORMAL
TEMPERATURES SHOULD CONTINUE THROUGH SUNDAY. THE GFS...ECMWF...EKD MOS
PLUS GFS ENSEMBLE MEAN SUPPORT TEMPERATURES AROUND 10 DEGREES
BELOW NORMAL THROUGH SUNDAY WITH NORMAL TEMPERATURES MONDAY.
&&
.AVIATION /21Z MONDAY THROUGH SATURDAY/...
VFR CONDITIONS THROUGH MOST OF THE OVERNIGHT PERIOD THEN
DETERIORATING TO IFR AROUND 09Z.
HIGH PRESSURE ACROSS THE REGION WILL WEAKEN AND SHIFT INTO THE
ATLANTIC AS LOW PRESSURE ALONG THE NORTHWEST GULF COAST SHIFTS
NORTHEASTWARD. SCATTERED MID-HIGH LEVEL CLOUDS WILL BEGIN TO
LOWER TO 10-12 KFT AND THICKEN BY 00Z THIS EVENING. WITH MOISTURE
FLUX TO THE AREA AHEAD OF APPROACHING WEATHER SYSTEM
TONIGHT...CEILINGS WILL CONTINUE TO LOWER TO 3-4 KFT BY 04Z-06Z
TIME FRAME. LIGHT RAIN SHOULD SPREAD INTO THE AREA AROUND 08Z-09Z
AND CONTINUE SPREADING TOWARD THE NORTHEAST AS THE SURFACE LOW
APPROACHES. BY 10Z-12Z...WIDESPREAD RAINFALL IS EXPECTED AND
CONDITIONS SHOULD DETERIORATE RAPIDLY TO IFR. AT THE MORE
NORTHEAST TAF SITES LIKE CAE AND CUB...IFR CONDITIONS MAY BE
DELAYED AS LONG AS 14Z BUT CONDITIONS WILL ALSO DETERIORATE
RAPIDLY AT THOSE LOCATIONS WHEN THE RAIN MOVES IN. AFTER
14Z...WIDESPREAD IFR CONDITIONS AND VSBYS AT WESTERN TAF SITES OF
AGS AND DNL MAY LOWER TO BELOW 1 MILE IN RAIN AT TIMES. MAINLY
MODERATE RAIN ON TUESDAY BUT DUE TO INCREASING ISENTROPIC
LIFT...CANNOT RULE OUT SOME HEAVY RAIN ESPECIALLY AT THE WESTERN
TAF SITES. ALSO WITH INCREASING INSTABILITY ALOFT...A FEW ELEVATED
THUNDERSTORMS ARE POSSIBLE BUT CONFIDENCE WAS TOO LOW TO INCLUDE
IN THIS TAF PACKAGE.
EXTENDED AVIATION OUTLOOK...AN EXTENDED PERIOD OF CIG/VSBY
RESTRICTIONS ARE POSSIBLE TUESDAY AFTERNOON THROUGH WEDNESDAY
NIGHT AS A LOW PRESSURE SYSTEM FROM THE GULF OF MEX CROSSES THE
SOUTHEASTERN STATES.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
218 PM EST MON NOV 25 2013
.SYNOPSIS...
MOISTURE WILL OVERSPREAD THE FORECAST AREA TONIGHT AHEAD OF LOW
PRESSURE DEVELOPING ALONG THE GULF COAST. THE LOW WILL MOVE
NORTHEAST ACROSS THE OUR AREA TUESDAY AND TUESDAY NIGHT...BRINGING
WIDESPREAD RAIN. THE LOW WILL LIFT NORTHEAST OF THE REGION
WEDNESDAY WITH COLD AND DRY HIGH PRESSURE RETURNING THANKSGIVING
DAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
THIS AFTERNOON...HIGH PRESSURE WILL WEAKEN THIS AFTERNOON AS A
WEATHER SYSTEM DEVELOPS IN THE WESTERN GULF COAST STATES OF TEXAS
AND LOUISIANA. THE UPPER RIDGE AXIS OVER THE FA WILL SHIFT EAST
AND ALLOW HIGH AND MID LEVEL CLOUDS TO ENTER THE REGION FROM
THE WEST. STILL COOL AND DRY CONDITIONS IN THE LOWER LAYERS.
AFTERNOON HIGHS MAINLY IN THE MID TO UPPER 40S. A BIT WARMER
IN THE CSRA AND AGS MAY HIT 51 OR 52. LIGHT MAINLY EASTERLY
WINDS ARE EXPECTED. DEWPOINTS IN THE SINGLE DIGITS EARLY THIS
AFTERNOON SHOULD INCREASE TO 10-15 DEGREES BY LATE AFTERNOON
AS MOISTURE BEGINS TO ENTER AREA.
TONIGHT...THE LATEST WATER VAPOR IMAGERY SHOWED A DIFLUENT PATTERN
OVER THE WESTERN GULF OF MEXICO AND LOW PRESSURE IS DEVELOPING
ALONG THE GULF COAST. ALL MODELS INDICATE INCREASING ISENTROPIC
LIFT AHEAD OF THIS LOW WILL RESULT IN PRECIPITATION OVERSPREADING
THE FORECAST AREA FROM SOUTHWEST TO NORTHEAST TONIGHT. THE HRRR
PLUS SATELLITE AND RADAR TRENDS INDICATE THE PRECIPITATION WILL HOLD
OFF UNTIL LATE TONIGHT. THE 1600 GMT HRRR INDICATED AREAS OF LIGHT
PRECIPITATION DEVELOPING IN THE WEST PART OF THE FORECAST AREA
AROUND MIDNIGHT...WITH THE BULK OF THE PRECIPITATION ABOUT TO MOVE
INTO THE WEST PART OF THE AREA AT 200 AM. USED THIS GUIDANCE FOR
THE TIMING.
THE MODELS INDICATE ENOUGH WARMING SHOULD OCCUR FOR ALL LIQUID
PRECIPITATION. ALL SREF MEMBERS KEEP THE SURFACE TEMPERATURE ABOVE
FREEZING LATE TONIGHT...EVEN IN THE NORTH PART. FREEZING RAIN IS
NOT IMPOSSIBLE IN THE EXTREME NORTH SECTION...BUT BELIEVE
PRECIPITATION WILL BE LIGHT AT THE ONSET LIMITING WET-BULB
COOLING. ALSO...THE NAM AND GFS SHOW SURFACE WET-BULB TEMPERATURES
RISING ABOVE FREEZING BEFORE SIGNIFICANT PRECIPITATION REACHES THE
AREA LATE TONIGHT. DESPITE THE MODEL GUIDANCE...THERE MAY BE
LAYERS OF DRY AIR ALOFT WITH WET-BULB COOLING WHICH COULD SUPPORT
SLEET. WE BELIEVE ANY SLEET WOULD BE LIGHT AND WITH SURFACE
TEMPERATURES JUST ABOVE FREEZING...NO ACCUMULATION SHOULD OCCUR.
WE USED THE COOLER TEMPERATURE GUIDANCE TONIGHT BECAUSE OF THE
DRY AIR IN PLACE AND EVAPORATIVE COOLING ASSOCIATED WITH THE
MOISTURE INCREASE.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
TUESDAY THROUGH WEDNESDAY...THE NAM AND GFS INDICATE THE BULK OF
THE RAINFALL WILL OCCUR DURING THE TUESDAY AND TUESDAY NIGHT TIME
FRAME WITH STRONG ISENTROPIC LIFT AND APPROACHING H5 SHORTWAVE
TROUGH. THE NAM...GFS AND SREF MEAN SUPPORT TOTAL RAINFALL FROM
1.5 TO AROUND 2.0 INCHES. THE NAM SHOWS CROSS TOTALS NEAR 25
TUESDAY AND TUESDAY NIGHT...SO A FEW ELEVATED THUNDERSTORMS MAY
OCCUR. THE SURFACE LOW WILL BE NORTHEAST OF THE AREA WITH THE
UPPER TROUGH OVERHEAD WEDNESDAY. WE MAY HAVE LINGERING MORNING
RAIN. STRONG COLD ADVECTION AND DRY AIR WILL POUR INTO THE AREA
WEDNESDAY AFTERNOON.
THE NAM LI-PATTERN INDICATES A WEDGE-TYPE PATTERN TUESDAY. WE
LEANED TOWARD THE IN-HOUSE WEDGE SCHEME FOR THE HIGH TEMPERATURE
FORECAST. EXPECT A NEAR STEADY TEMPERATURE TUESDAY NIGHT. USED
THE COLDER TEMPERATURE GUIDANCE WEDNESDAY BECAUSE OF LINGERING
CLOUDINESS AND A SHARP UPPER TROUGH OVER OUR AREA.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
THE GFS AND ECMWF ARE IN GOOD AGREEMENT SHOWING DRY HIGH PRESSURE
DOMINATING DURING MUCH OF THE THE MEDIUM-RANGE PERIOD. AN ONSHORE
FLOW AND WARM FRONT MAY SUPPORT RAIN MONDAY. BELOW NORMAL
TEMPERATURES SHOULD CONTINUE THROUGH SUNDAY. THE GFS...ECMWF...EKD MOS
PLUS GFS ENSEMBLE MEAN SUPPORT TEMPERATURES AROUND 10 DEGREES
BELOW NORMAL THROUGH SUNDAY WITH NORMAL TEMPERATURES MONDAY.
&&
.AVIATION /19Z MONDAY THROUGH SATURDAY/...
HIGH PRESSURE ACROSS THE REGION WILL WEAKEN THIS AFTERNOON
AS LOW PRESSURE DEVELOPS ALONG THE NORTHWEST GULF COAST THIS
EVENING. VFR CONDITIONS THIS AFTERNOON THROUGH MOST OF THE
OVERNIGHT PERIOD. SCATTERED MID-HIGH LEVEL CLOUDS THIS AFTERNOON
WILL BEGIN TO LOWER AND THICKEN BY 00Z THIS EVENING. CEILINGS
LOWERING TO 10-12 KFT. WITH MOISTURE FLUX TO THE AREA AHEAD OF
APPROACHING WEATHER SYSTEM TONIGHT...CEILINGS TO CONTINUE LOWER
TO 3-4 KFT BY 04Z-06Z TIME FRAME. LIGHT RAIN SHOULD SPREAD INTO
THE AREA AROUND 08Z-09Z AND CONTINUE SPREADING TOWARD THE
NORTHEAST AS THE SURFACE LOW APPROACHES. BY 10Z-12Z...WIDESPREAD
RAINFALL IS EXPECTED AND CONDITIONS SHOULD DETERIORATE RAPIDLY TO
IFR. AT THE MORE NORTHEAST TAF SITES LIKE CAE AND CUB...IFR
CONDITIONS MAY BE DELAYED AS LONG AS 14Z BUT CONDITIONS WILL ALSO
DETERIORATE RAPIDLY AS THOSE LOCATIONS WHEN THE RAIN MOVES IN.
AFTER 14Z...WIDESPREAD IFR CONDITIONS AND VSBYS AT WESTERN TAF
SITES OF AGS AND DNL MAY LOWER TO BELOW 1 MILE IN RAIN AT TIMES.
MAINLY MODERATE RAIN ON TUESDAY BUT DUE TO INCREASING ISENTROPIC
LIFT...CANNOT RULE OUT SOME HEAVY RAIN ESPECIALLY AT THE WESTERN
TAF SITES. ALSO WITH INCREASING INSTABILITY ALOFT...A FEW ELEVATED
THUNDERSTORMS ARE POSSIBLE BUT CONFIDENCE WAS TOO LOW TO INCLUDE
IN THIS TAF PACKAGE.
EXTENDED AVIATION OUTLOOK...AN EXTENDED PERIOD OF CIG/VSBY
RESTRICTIONS ARE POSSIBLE TUESDAY AFTERNOON THROUGH WEDNESDAY
NIGHT AS A LOW PRESSURE SYSTEM FROM THE GULF OF MEX CROSSES THE
SOUTHEASTERN STATES.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
208 PM CST MON NOV 25 2013
.DISCUSSION...
1040 AM CST
FOR MORNING UPDATE...
HAVE BUMPED SNOWFALL AMOUNTS JUST A BIT...TO AROUND 1 INCH...ALONG
THE WI/IL STATE LINE. OTHERWISE...ONLY MINOR TWEAKS TO NEAR TERM OF
GOING FORECAST.
MORNING WATER VAPOR IMAGERY AND 12Z UPPER AIR ANALYSIS DEPICT FAIRLY
STRONG MID-LEVEL SHORT WAVE TROUGH PROPAGATING ACROSS THE UPPER
MIDWEST AND NORTHERN GREAT LAKES REGION. MAIN AREA OF SURFACE LOW
PRESSURE WAS NORTH OF LAKE SUPERIOR...WHILE AN AREA OF ENHANCED LOW
LEVEL WARM ADVECTION WAS OCCURRING ACROSS IOWA...SOUTHEAST
MINNESOTA...WISCONSIN AND FAR NORTH/NORTHWEST ILLINOIS. ISENTROPIC
ASCENT AND MOISTURE ADVECTION WAS PRODUCING TOP-DOWN SATURATION IN A
NARROW CORRIDOR FROM DSM-DBQ-MKE...WITH LIGHT SNOW LOWERING
VISIBILITY TO 1/2 MILE IN SOME SPOTS ACROSS FAR SOUTHERN WI.
CONSIDERABLE DRY AIR BELOW 800-700 MB IN DVN AND ILX 12Z...WHICH
INDICATES FORCING WILL HAVE TO WORK TO SATURATE LOWER LEVELS ACROSS
IL/IN TODAY. WITH STRONGEST WARM ADVECTION AND JET DYNAMICS EXPECTED
TO PROVIDE THE BEST FORCING THIS MORNING...BAND OF SNOW SHOULD HAVE
A HARDER TIME PRODUCING MODERATE SNOW FARTHER SOUTHEAST INTO IL AND
NORTHWEST IN.
A FEW REPORTS FROM NORTHEAST IA OF 3-5 INCH SNOWFALL AMOUNTS WITH
INITIAL STRONG BANDING EARLY THIS MORNING...THOUGH WITH FORCING
WEAKENING SOMEWHAT WITH TIME AND DRY LOW-LEVELS TO OVERCOME WOULD
EXPECT AMOUNTS TO TAPER QUICKLY INTO THE LOT CWA. BASED ON RADAR
TRENDS THROUGH THE MORNING...AND SOME WEB CAM IMAGERY FROM AREAS
ALONG AND NORTH OF RFD-UGN WHERE A FEW TENTHS OF ACCUM ALREADY HAS
OCCURRED...HAVE BUMPED SNOWFALL AMOUNTS A BIT TO AROUND AN INCH
ACROSS NORTHERN PARTS OF THE NORTHERN TIER COUNTIES...TO LESS THAN A
HALF INCH FROM ROUGHLY I-88 SOUTH.
RATZER
//PREV DISCUSSION...
323 AM CST
WITH NOVEMBER LOOKING TO FINISH WITH CONTINUED BELOW NORMAL
TEMPERATURES DURING ITS FINAL WEEK WITH LITTLE IN THE WAY OF SHARP
THERMAL CHANGES...THE PRIMARY FOCUS OF THE FORECAST WAS ON THE LIGHT
SNOW EVENT TODAY AND THEN THE LAKE EFFECT SNOW POTENTIAL INTO
NORTHWEST INDIANA TUESDAY NIGHT AND WEDNESDAY.
SOMEWHAT SPLIT UPPER FLOW IS IN PLACE ACROSS THE CENTRAL U.S. THIS
MONDAY WITH A QUICKLY-MOVING TROUGH ACROSS ONTARIO DIVING INTO THE
GREAT LAKES BY AFTERNOON...AND A CLOSED LOW ACROSS THE TEXAS
PANHANDLE BRINGING RARE NOVEMBER WINTER WEATHER HEADLINES TO THE
SOUTHERN PLAINS. OUR FORECAST AREA BASICALLY FALLS BETWEEN THESE TWO
SYSTEMS TODAY AND AS A RESULT THERE IS A VOID OF ANY OVERLY STRONG
FORCING OVERHEAD. ISENTROPIC ASCENT AND SATURATION WITHIN THE WSW
FLOW ALOFT THIS MORNING LOOKS TO BE THE PRIMARY CONTRIBUTOR TO
PRECIPITATION GENERATION...ALTHOUGH DRY LOW-LEVELS MAY KEEP IT
FLURRIES THROUGH MID TO LATE MORNING OVER CHICAGO. AN AXIS OF
FRONTOGENESIS CENTERED TO THE NORTHWEST OF THE AREA FROM EASTERN IA
INTO SOUTHERN WI THROUGH ~10 AM ON THE RAP AND LOCAL ARW MAY RESULT
IN BETTER SNOWFALL CLIPPING THE ROCKFORD AREA THIS MORNING...AND
CONCEIVABLY COULD SEE AN INCH BECAUSE OF THAT BUT THAT WOULD SEEM
THE MAXIMUM. AS THE SUBTLE FORCING AND MID-LEVEL SATURATION EVOLVES
EAST INTO THE AFTERNOON...PERIODS OF LIGHT SNOW WILL LIKELY RESULT
IN ONE HALF INCH OR LESS FOR MOST COMMUNITIES...AND NAMELY NORTH OF
I-80. WHILE NOT THE MOST IDEAL SYNOPTIC SETUP FOR FREEZING
DRIZZLE...THERE ARE SOME SIGNS ON GUIDANCE THAT AS ICE INTRODUCTION
IS LOST DURING THE MID TO LATE AFTERNOON THAT THERE MAY BE A BRIEF
WINDOW FOR THIS. ASCENT LOOKS WEAK AND CLOUD BASES LOOK HIGH FOR
THAT TO OCCUR THOUGH...SO CONTINUE TO NOT MENTION IN FORECAST.
THE AMOUNT OF CLOUD COVER TODAY WILL ONLY ALLOW TEMPERATURES TO RISE
BY ADVECTION...AND THAT WILL BE MEAGER AT THE SURFACE. SO MAINTAIN
HIGHS MAINLY IN THE LOWER 30S...WHICH WOULD RESULT IN THE THIRD
STRAIGHT DAY OF DOUBLE DIGIT DEPARTURES BELOW NORMAL.
A SECOND MORE ROBUST NORTHERN STREAM WAVE...THAT ACTUALLY LOOKS TO
BE A CLOSED SUB 520DM H5 LOW...WILL DROP INTO THE GREAT LAKES ON
TUESDAY. A FAIRLY DEEP PV ANOMALY IS SEEN WITH THIS ALONG WITH H5
TEMPS DOWN TO NEAR -30C...WHICH COME BARRELING INTO THE FORECAST
AREA BY LATE AFTERNOON INTO THE EVE TUESDAY ON THE GUIDANCE SUITE.
AN ASSOCIATED SURFACE COLD FRONT LOOKS TO STEEPEN LAPSE RATES AND
COULD SUPPORT SOME SNOW SHOWERS. CERTAINLY SOME FLURRIES LOOK TO BE
PRESENT INTO TUESDAY NIGHT. LOWS THAT NIGHT LOOK TO RETURN TO THE
MID AND POSSIBLY EVEN LOWER TEENS IN OUTLYING LOCATIONS.
MORE OF A CONCERN IS TURNING TO A POTENTIAL PLOWABLE SNOW FROM LAKE
EFFECT GENERATION INTO NORTHWEST INDIANA TUESDAY NIGHT INTO THE
BUSIEST TRAVEL DAY OF THE YEAR ON WEDNESDAY. THERE REMAINS MODEL
DIFFERENCES ON HOW QUICKLY THE AFOREMENTIONED SOUTHERN PLAINS UPPER
LOW AND THIS GREAT LAKES LOW PHASE. BUT OVERALL THE FLOW ACROSS LAKE
MI SHOULD BECOME STIFF AND NORTHERLY BY LATER TUESDAY NIGHT. THERE
ARE EVEN SIGNS ON SOME HIGH RESOLUTION MODELS...INCLUDING OUR LOCAL
ARW...OF MESO-LOW DEVELOPMENT TRANSLATING SOUTH ACROSS THE LAKE ON
TUESDAY NIGHT. CONFIDENCE ON SUCH A FEATURE IS LOW AT THIS
POINT...AS IS WHETHER THERE WILL EXIST A FOCUSED BAND OR JUST
WIDESPREAD SHOWERS OFF THE LAKE. BUT CONFIDENCE IS HIGH THERE WILL
BE AT LEAST SNOW SHOWERS INTO NORTHWEST INDIANA GIVE THE FORECAST
TRAJECTORIES...STEEP LOW-LEVEL LAPSE RATES...LAKE-INDUCED CAPE OF
AROUND 500 J/KG...AND EQUILIBRIUM LEVELS FORECAST AROUND 9000 FT.
THESE INDICES ACTUALLY INDICATE SOMEWHERE COULD GET A ROBUST SNOW
EVENT WITH HEAVY RATES WHICH WOULD IMPACT WEDNESDAY TRAVEL. IN
ADDITION...USING THE CIPS ANALOGS INDICATES A FAIRLY STRONG
CORRELATED EVENT FOR 850MB TEMPERATURES AND LOW-LEVEL WIND FLOW ON
11/21/08 AND THAT PRODUCED OVER 8 INCHES JUST EAST OF THE AREA. AT
THIS TIME HAVE CONTINUED THE TREND OF PREVIOUS SHIFT IN INCREASING
POPS ACROSS PORTER AND EASTERN LAKE COUNTIES.
BEYOND THERE WAS LITTLE CHANGE TO THE FORECAST AS THE HOLIDAY ITSELF
LOOKS QUIET ACROSS THE AREA WITH GRADUALLY BUILDING HEIGHTS AND
SURFACE HIGH PRESSURE. A QUASI-ZONAL PATTERN IS FAVORED ON LONG
RANGE DETERMINISTIC MODELS AND ENSEMBLES...WHICH WOULD FAVOR A
GRADUAL MODERATION TO NEAR NORMAL FOR THE FIRST DAY OF
METEOROLOGICAL WINTER ON SUNDAY.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* GUSTY SOUTHWEST WINDS THROUGH LATE AFTERNOON.
* PERIODS OF LIGHT SNOW THROUGH LATE AFTERNOON TO EARLY EVENING
WITH PERIODS OF 3-4SM VIS.
* OCNL SMALL AREAS OF HEAVIER SNOW WILL RIPPLE THROUGH THE GENERAL
SNOW BAND DROPPING VIS TO 1-2SM FOR THE NEXT 2 HRS.
* MVFR CIGS TO PERSIST UNTIL LATE TONIGHT.
KREIN
//DISCUSSION...UPDATED 18Z...
MAIN CONCERNS FOR THE REMAINDER OF THE AFTERNOON WILL FOCUS ON
IMPACTS OF LIGHT SNOW AS WELL AS GUSTY SWLY WINDS.
AT THE CURRENT TIME...A BAND OF LIGHT WARM ADVECTION SNOW IS
SAGGING SWD THROUGH NRN IL AND WILL SOON MOVE INTO NWRN INDIANA.
SOUTH OF THE BAND...SCT UNORGANIZED AREAS OF LIGHT SNOW ARE ALSO
MOVING THROUGH THE AREA. THE LATEST RADAR TRENDS INDICATE THAT THE
SNOW BAND IS BECOMING A LITTLE LESS ORGANIZED AS IT SAGS TO THE
SOUTH...BUT STILL EXPECT A PERIOD OF SNOW TO IMPACT THE TERMINALS.
WHILE THE SNOW IS RELATIVELY LIGHT AND ACCUMULATIONS GENERALLY NOT
A MAJOR CONCERN AT THE TERMINALS...THE BIGGEST IMPACT WILL BE ON
VISIBILITY DUE TO THE STRONG...GUSTY WINDS. SO...EXPECT A PERIOD
OF ABOUT 2 HRS WHERE THE SNOWFALL RATE SILL BE HIGH
ENOUGH...COMBINED WITH THE STRONG WINDS TO REDUCE VISIBILITY TO
1-2SM. AND THE MAIN BAND OF SNOW SAGS SOUTH OF THE TERMINALS INTO
CNTRL IL/IN...THERE SHOULD STILL BE SOME LIGHT SNOW FALLING...BUT
GENERALLY VISIBILITY SHOULD RETURN TO VFR LEVELS. HOWEVER...MVFR
CIGS SHOULD PERSIST WELL INTO THE EVENING AND LATE NIGHT HOURS AS
COOLER AIR WRAPS AROUND A DEEP LOW PRESSURE SYSTEM TRACKING
THROUGH THE UPPER GREAT LAKES. WITH THE AREA BETWEEN AN
APPROACHING COLD FRONT ASSOCIATED WITH THE LOW TO THE NORTH AND
HIGH PRESSURE SITTING OVER THE MID ATLANTIC REGION...A SWLY
GRADIENT WILL REMAIN IN PLACE UNTIL THE FRONT SWEEPS THROUGH THE
REGION. LATEST MODEL GUIDANCE SUGGESTS THAT THE FRONT WILL MOVE
THROUGH NRN IL/IN BY LATE TOMORROW MORNING...AT WHICH TIME WINDS
WILL QUICKLY SHIFT FROM SWLY TO NWLY.
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE IN WIND TRENDS.
* LOW TO MEDIUM CONFIDENCE DURATION OF MVFR AND IFR VIS ASSOCIATED
WITH WIND DRIVEN SNOW.
* MEDIUM CONFIDENCE IN CIG TRENDS.
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...
TUESDAY NIGHT...FLURRIES IN THE EVENING WITH MVFR CIGS LIFTING TO
VFR.
WEDNESDAY...LAKE EFFECT MVFR CIGS PSBL.
THURSDAY AND FRIDAY...VFR.
SATURDAY...MVFR CIGS PSBL OVERNIGHT.
SUNDAY...MVFR CIGS PSBL
KJB
&&
.MARINE...
208 PM...LOW PRESSURE OVER EASTERN ONTARIO WILL MOVE INTO QUEBEC
TONIGHT AS IT SLOWLY WEAKENS...ALLOWING THE GRADIENT OVER LAKE
MICHIGAN TO SLOWLY RELAX WITH GALES STILL POSSIBLE EARLY THIS
EVENING. SPEEDS WILL DIMINISH INTO THE 15-20KT RANGE LATER TONIGHT
INTO TUESDAY MORNING. A TRAILING COLD FRONT FROM THE LOW MOVING
INTO QUEBEC WILL MOVE ACROSS THE LAKE TUESDAY AFTERNOON...WITH
ANOTHER WEAKER LOW DEVELOPING ALONG THE FRONT OVER LAKE SUPERIOR
TONIGHT. ONCE THIS FRONT PASSES EAST OF THE LAKE...WINDS WILL
SHIFT TO THE NORTHWEST AND STEADILY INCREASE AS THE GRADIENT
TIGHTENS IN RESPONSE TO STRONG HIGH PRESSURE MOVE SOUTH ACROSS
THE PLAINS TUESDAY AFTERNOON INTO TUESDAY NIGHT...COMBINED WITH A
STRONG LOW MOVING NORTH ACROSS THE EASTERN SEABOARD. ITS POSSIBLE
FOR A SHORTER PERIOD OF GALES ON THE NORTH HALF OF THE LAKE LATE
TUESDAY AFTERNOON INTO TUESDAY EVENING...BUT A MORE PROLONGED
PERIOD OF LOW END GALES APPEARS POSSIBLE OVER THE SOUTH HALF OF
THE LAKE TUESDAY NIGHT INTO WEDNESDAY MORNING WHEN THE GRADIENT
SHOULD BE THE TIGHTEST. THE LOW MOVING UP THE EAST COAST WILL
CONTINUE TO DEEPEN AS IT MOVES INTO QUEBEC WEDNESDAY NIGHT WITH
THE HIGH SPREADING SOUTH INTO THE SOUTHERN PLAINS AND GULF COAST
STATES. A WEAKER RIDGE WILL PASS ACROSS THE LAKE WITH SPEEDS
SLOWLY DIMINISHING WEDNESDAY AFTERNOON THROUGH THURSDAY MORNING.
THE HIGH WILL BECOME SPRAWLING ACROSS THE EASTERN HALF OR TWO
THIRDS OF THE U.S. THURSDAY NIGHT INTO FRIDAY WITH PRIMARILY
WESTERLY FLOW FLOPPING AROUND SOUTHEAST FRIDAY NIGHT. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 PM MONDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 9 PM MONDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
145 PM CST MON NOV 25 2013
.DISCUSSION...
1040 AM CST
FOR MORNING UPDATE...
HAVE BUMPED SNOWFALL AMOUNTS JUST A BIT...TO AROUND 1 INCH...ALONG
THE WI/IL STATE LINE. OTHERWISE...ONLY MINOR TWEAKS TO NEAR TERM OF
GOING FORECAST.
MORNING WATER VAPOR IMAGERY AND 12Z UPPER AIR ANALYSIS DEPICT FAIRLY
STRONG MID-LEVEL SHORT WAVE TROUGH PROPAGATING ACROSS THE UPPER
MIDWEST AND NORTHERN GREAT LAKES REGION. MAIN AREA OF SURFACE LOW
PRESSURE WAS NORTH OF LAKE SUPERIOR...WHILE AN AREA OF ENHANCED LOW
LEVEL WARM ADVECTION WAS OCCURRING ACROSS IOWA...SOUTHEAST
MINNESOTA...WISCONSIN AND FAR NORTH/NORTHWEST ILLINOIS. ISENTROPIC
ASCENT AND MOISTURE ADVECTION WAS PRODUCING TOP-DOWN SATURATION IN A
NARROW CORRIDOR FROM DSM-DBQ-MKE...WITH LIGHT SNOW LOWERING
VISIBILITY TO 1/2 MILE IN SOME SPOTS ACROSS FAR SOUTHERN WI.
CONSIDERABLE DRY AIR BELOW 800-700 MB IN DVN AND ILX 12Z...WHICH
INDICATES FORCING WILL HAVE TO WORK TO SATURATE LOWER LEVELS ACROSS
IL/IN TODAY. WITH STRONGEST WARM ADVECTION AND JET DYNAMICS EXPECTED
TO PROVIDE THE BEST FORCING THIS MORNING...BAND OF SNOW SHOULD HAVE
A HARDER TIME PRODUCING MODERATE SNOW FARTHER SOUTHEAST INTO IL AND
NORTHWEST IN.
A FEW REPORTS FROM NORTHEAST IA OF 3-5 INCH SNOWFALL AMOUNTS WITH
INITIAL STRONG BANDING EARLY THIS MORNING...THOUGH WITH FORCING
WEAKENING SOMEWHAT WITH TIME AND DRY LOW-LEVELS TO OVERCOME WOULD
EXPECT AMOUNTS TO TAPER QUICKLY INTO THE LOT CWA. BASED ON RADAR
TRENDS THROUGH THE MORNING...AND SOME WEB CAM IMAGERY FROM AREAS
ALONG AND NORTH OF RFD-UGN WHERE A FEW TENTHS OF ACCUM ALREADY HAS
OCCURRED...HAVE BUMPED SNOWFALL AMOUNTS A BIT TO AROUND AN INCH
ACROSS NORTHERN PARTS OF THE NORTHERN TIER COUNTIES...TO LESS THAN A
HALF INCH FROM ROUGHLY I-88 SOUTH.
RATZER
//PREV DISCUSSION...
323 AM CST
WITH NOVEMBER LOOKING TO FINISH WITH CONTINUED BELOW NORMAL
TEMPERATURES DURING ITS FINAL WEEK WITH LITTLE IN THE WAY OF SHARP
THERMAL CHANGES...THE PRIMARY FOCUS OF THE FORECAST WAS ON THE LIGHT
SNOW EVENT TODAY AND THEN THE LAKE EFFECT SNOW POTENTIAL INTO
NORTHWEST INDIANA TUESDAY NIGHT AND WEDNESDAY.
SOMEWHAT SPLIT UPPER FLOW IS IN PLACE ACROSS THE CENTRAL U.S. THIS
MONDAY WITH A QUICKLY-MOVING TROUGH ACROSS ONTARIO DIVING INTO THE
GREAT LAKES BY AFTERNOON...AND A CLOSED LOW ACROSS THE TEXAS
PANHANDLE BRINGING RARE NOVEMBER WINTER WEATHER HEADLINES TO THE
SOUTHERN PLAINS. OUR FORECAST AREA BASICALLY FALLS BETWEEN THESE TWO
SYSTEMS TODAY AND AS A RESULT THERE IS A VOID OF ANY OVERLY STRONG
FORCING OVERHEAD. ISENTROPIC ASCENT AND SATURATION WITHIN THE WSW
FLOW ALOFT THIS MORNING LOOKS TO BE THE PRIMARY CONTRIBUTOR TO
PRECIPITATION GENERATION...ALTHOUGH DRY LOW-LEVELS MAY KEEP IT
FLURRIES THROUGH MID TO LATE MORNING OVER CHICAGO. AN AXIS OF
FRONTOGENESIS CENTERED TO THE NORTHWEST OF THE AREA FROM EASTERN IA
INTO SOUTHERN WI THROUGH ~10 AM ON THE RAP AND LOCAL ARW MAY RESULT
IN BETTER SNOWFALL CLIPPING THE ROCKFORD AREA THIS MORNING...AND
CONCEIVABLY COULD SEE AN INCH BECAUSE OF THAT BUT THAT WOULD SEEM
THE MAXIMUM. AS THE SUBTLE FORCING AND MID-LEVEL SATURATION EVOLVES
EAST INTO THE AFTERNOON...PERIODS OF LIGHT SNOW WILL LIKELY RESULT
IN ONE HALF INCH OR LESS FOR MOST COMMUNITIES...AND NAMELY NORTH OF
I-80. WHILE NOT THE MOST IDEAL SYNOPTIC SETUP FOR FREEZING
DRIZZLE...THERE ARE SOME SIGNS ON GUIDANCE THAT AS ICE INTRODUCTION
IS LOST DURING THE MID TO LATE AFTERNOON THAT THERE MAY BE A BRIEF
WINDOW FOR THIS. ASCENT LOOKS WEAK AND CLOUD BASES LOOK HIGH FOR
THAT TO OCCUR THOUGH...SO CONTINUE TO NOT MENTION IN FORECAST.
THE AMOUNT OF CLOUD COVER TODAY WILL ONLY ALLOW TEMPERATURES TO RISE
BY ADVECTION...AND THAT WILL BE MEAGER AT THE SURFACE. SO MAINTAIN
HIGHS MAINLY IN THE LOWER 30S...WHICH WOULD RESULT IN THE THIRD
STRAIGHT DAY OF DOUBLE DIGIT DEPARTURES BELOW NORMAL.
A SECOND MORE ROBUST NORTHERN STREAM WAVE...THAT ACTUALLY LOOKS TO
BE A CLOSED SUB 520DM H5 LOW...WILL DROP INTO THE GREAT LAKES ON
TUESDAY. A FAIRLY DEEP PV ANOMALY IS SEEN WITH THIS ALONG WITH H5
TEMPS DOWN TO NEAR -30C...WHICH COME BARRELING INTO THE FORECAST
AREA BY LATE AFTERNOON INTO THE EVE TUESDAY ON THE GUIDANCE SUITE.
AN ASSOCIATED SURFACE COLD FRONT LOOKS TO STEEPEN LAPSE RATES AND
COULD SUPPORT SOME SNOW SHOWERS. CERTAINLY SOME FLURRIES LOOK TO BE
PRESENT INTO TUESDAY NIGHT. LOWS THAT NIGHT LOOK TO RETURN TO THE
MID AND POSSIBLY EVEN LOWER TEENS IN OUTLYING LOCATIONS.
MORE OF A CONCERN IS TURNING TO A POTENTIAL PLOWABLE SNOW FROM LAKE
EFFECT GENERATION INTO NORTHWEST INDIANA TUESDAY NIGHT INTO THE
BUSIEST TRAVEL DAY OF THE YEAR ON WEDNESDAY. THERE REMAINS MODEL
DIFFERENCES ON HOW QUICKLY THE AFOREMENTIONED SOUTHERN PLAINS UPPER
LOW AND THIS GREAT LAKES LOW PHASE. BUT OVERALL THE FLOW ACROSS LAKE
MI SHOULD BECOME STIFF AND NORTHERLY BY LATER TUESDAY NIGHT. THERE
ARE EVEN SIGNS ON SOME HIGH RESOLUTION MODELS...INCLUDING OUR LOCAL
ARW...OF MESO-LOW DEVELOPMENT TRANSLATING SOUTH ACROSS THE LAKE ON
TUESDAY NIGHT. CONFIDENCE ON SUCH A FEATURE IS LOW AT THIS
POINT...AS IS WHETHER THERE WILL EXIST A FOCUSED BAND OR JUST
WIDESPREAD SHOWERS OFF THE LAKE. BUT CONFIDENCE IS HIGH THERE WILL
BE AT LEAST SNOW SHOWERS INTO NORTHWEST INDIANA GIVE THE FORECAST
TRAJECTORIES...STEEP LOW-LEVEL LAPSE RATES...LAKE-INDUCED CAPE OF
AROUND 500 J/KG...AND EQUILIBRIUM LEVELS FORECAST AROUND 9000 FT.
THESE INDICES ACTUALLY INDICATE SOMEWHERE COULD GET A ROBUST SNOW
EVENT WITH HEAVY RATES WHICH WOULD IMPACT WEDNESDAY TRAVEL. IN
ADDITION...USING THE CIPS ANALOGS INDICATES A FAIRLY STRONG
CORRELATED EVENT FOR 850MB TEMPERATURES AND LOW-LEVEL WIND FLOW ON
11/21/08 AND THAT PRODUCED OVER 8 INCHES JUST EAST OF THE AREA. AT
THIS TIME HAVE CONTINUED THE TREND OF PREVIOUS SHIFT IN INCREASING
POPS ACROSS PORTER AND EASTERN LAKE COUNTIES.
BEYOND THERE WAS LITTLE CHANGE TO THE FORECAST AS THE HOLIDAY ITSELF
LOOKS QUIET ACROSS THE AREA WITH GRADUALLY BUILDING HEIGHTS AND
SURFACE HIGH PRESSURE. A QUASI-ZONAL PATTERN IS FAVORED ON LONG
RANGE DETERMINISTIC MODELS AND ENSEMBLES...WHICH WOULD FAVOR A
GRADUAL MODERATION TO NEAR NORMAL FOR THE FIRST DAY OF
METEOROLOGICAL WINTER ON SUNDAY.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* GUSTY SOUTHWEST WINDS THROUGH LATE AFTERNOON.
* PERIODS OF LIGHT SNOW THROUGH LATE AFTERNOON TO EARLY EVENING
WITH PERIODS OF 3-4SM VIS.
* OCNL SMALL AREAS OF HEAVIER SNOW WILL RIPPLE THROUGH THE GENERAL
SNOW BAND DROPPING VIS TO 1-2SM FOR THE NEXT 2 HRS.
* MVFR CIGS TO PERSIST UNTIL LATE TONIGHT.
KREIN
//DISCUSSION...UPDATED 18Z...
MAIN CONCERNS FOR THE REMAINDER OF THE AFTERNOON WILL FOCUS ON
IMPACTS OF LIGHT SNOW AS WELL AS GUSTY SWLY WINDS.
AT THE CURRENT TIME...A BAND OF LIGHT WARM ADVECTION SNOW IS
SAGGING SWD THROUGH NRN IL AND WILL SOON MOVE INTO NWRN INDIANA.
SOUTH OF THE BAND...SCT UNORGANIZED AREAS OF LIGHT SNOW ARE ALSO
MOVING THROUGH THE AREA. THE LATEST RADAR TRENDS INDICATE THAT THE
SNOW BAND IS BECOMING A LITTLE LESS ORGANIZED AS IT SAGS TO THE
SOUTH...BUT STILL EXPECT A PERIOD OF SNOW TO IMPACT THE TERMINALS.
WHILE THE SNOW IS RELATIVELY LIGHT AND ACCUMULATIONS GENERALLY NOT
A MAJOR CONCERN AT THE TERMINALS...THE BIGGEST IMPACT WILL BE ON
VISIBILITY DUE TO THE STRONG...GUSTY WINDS. SO...EXPECT A PERIOD
OF ABOUT 2 HRS WHERE THE SNOWFALL RATE SILL BE HIGH
ENOUGH...COMBINED WITH THE STRONG WINDS TO REDUCE VISIBILITY TO
1-2SM. AND THE MAIN BAND OF SNOW SAGS SOUTH OF THE TERMINALS INTO
CNTRL IL/IN...THERE SHOULD STILL BE SOME LIGHT SNOW FALLING...BUT
GENERALLY VISIBILITY SHOULD RETURN TO VFR LEVELS. HOWEVER...MVFR
CIGS SHOULD PERSIST WELL INTO THE EVENING AND LATE NIGHT HOURS AS
COOLER AIR WRAPS AROUND A DEEP LOW PRESSURE SYSTEM TRACKING
THROUGH THE UPPER GREAT LAKES. WITH THE AREA BETWEEN AN
APPROACHING COLD FRONT ASSOCIATED WITH THE LOW TO THE NORTH AND
HIGH PRESSURE SITTING OVER THE MID ATLANTIC REGION...A SWLY
GRADIENT WILL REMAIN IN PLACE UNTIL THE FRONT SWEEPS THROUGH THE
REGION. LATEST MODEL GUIDANCE SUGGESTS THAT THE FRONT WILL MOVE
THROUGH NRN IL/IN BY LATE TOMORROW MORNING...AT WHICH TIME WINDS
WILL QUICKLY SHIFT FROM SWLY TO NWLY.
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE IN WIND TRENDS.
* LOW TO MEDIUM CONFIDENCE DURATION OF MVFR AND IFR VIS ASSOCIATED
WITH WIND DRIVEN SNOW.
* MEDIUM CONFIDENCE IN CIG TRENDS.
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...
TUESDAY NIGHT...FLURRIES IN THE EVENING WITH MVFR CIGS LIFTING TO
VFR.
WEDNESDAY...LAKE EFFECT MVFR CIGS PSBL.
THURSDAY AND FRIDAY...VFR.
SATURDAY...MVFR CIGS PSBL OVERNIGHT.
SUNDAY...MVFR CIGS PSBL
KJB
&&
.MARINE...
206 AM CST
A VERY ACTIVE WEATHER PATTERN WILL CONTINUE ACROSS THE GREAT LAKES
THROUGH MID WEEK. THE CURRENT GALE EVENT IS WELL UNDERWAY WITH
SEVERAL REPORTS OF 40+ KT WINDS...ESPECIALLY ACROSS THE NORTHERN
HALF OF THE LAKE. THESE GALES WILL CONTINUE THROUGH AT LEAST THE MID
AFTERNOON HOURS TODAY AS A AN AREA OF LOW PRESSURE TRACKS EASTWARD
ACROSS SOUTHERN ONTARIO. THE WINDS WILL GRADUALLY ABATE INTO THIS
EVENING. THE CURRENT GALE HEADLINE MAY BE ALOUD TO EXPIRE A FEW
HOURS EARLIER THAN THE CURRENT 9 PM DEADLINE. HOWEVER...AT THIS
POINT I WILL LEAVE THE HEADLINE TIMING ALONE.
THE NEXT ISSUE WILL BE LATER TUESDAY THROUGH MUCH OF WEDNESDAY. A
STRONG STORM SYSTEM IS EXPECTED TO MOVE UP THE EAST COAST DURING
THIS TIME...AND AS HIGH PRESSURE BUILDS IN ACROSS THE MISSOURI
VALLEY CONDITIONS WILL BECOME FAVORABLE FOR A PERIOD OF NORTHERLY
GALES UP TO 35 TO 40 KT. THIS LOOKS TO BE THE MOST PRONOUNCED ACROSS
SOUTHERN LAKE MICHIGAN...AND ANY LAKE EFFECT BANDS OF SNOW THAT
DEVELOP DURING THIS TIME COULD LEAD ALSO EVEN LEAD TO SOME LOCALLY
HIGH WINDS IN EXCESS OF 40 KT. IT APPEARS TO BE A GOOD BET THAT A
GALE HEADLINE WILL BE NEEDED DURING THIS TIME. I THREW AROUND THE
IDEA OF HOSTING A GALE WATCH FOR THIS PERIOD...BUT DUE TO THE FACT
IT IS STILL FAR ENOUGH OUT...I HAVE DECIDED TO LET THE CURRENT
GALE HEADLINES END PRIOR TO THE ISSUANCE OF A NEW HEADLINE.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 PM MONDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 9 PM MONDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1142 AM CST MON NOV 25 2013
.DISCUSSION...
1040 AM CST
FOR MORNING UPDATE...
HAVE BUMPED SNOWFALL AMOUNTS JUST A BIT...TO AROUND 1 INCH...ALONG
THE WI/IL STATE LINE. OTHERWISE...ONLY MINOR TWEAKS TO NEAR TERM OF
GOING FORECAST.
MORNING WATER VAPOR IMAGERY AND 12Z UPPER AIR ANALYSIS DEPICT FAIRLY
STRONG MID-LEVEL SHORT WAVE TROUGH PROPAGATING ACROSS THE UPPER
MIDWEST AND NORTHERN GREAT LAKES REGION. MAIN AREA OF SURFACE LOW
PRESSURE WAS NORTH OF LAKE SUPERIOR...WHILE AN AREA OF ENHANCED LOW
LEVEL WARM ADVECTION WAS OCCURRING ACROSS IOWA...SOUTHEAST
MINNESOTA...WISCONSIN AND FAR NORTH/NORTHWEST ILLINOIS. ISENTROPIC
ASCENT AND MOISTURE ADVECTION WAS PRODUCING TOP-DOWN SATURATION IN A
NARROW CORRIDOR FROM DSM-DBQ-MKE...WITH LIGHT SNOW LOWERING
VISIBILITY TO 1/2 MILE IN SOME SPOTS ACROSS FAR SOUTHERN WI.
CONSIDERABLE DRY AIR BELOW 800-700 MB IN DVN AND ILX 12Z...WHICH
INDICATES FORCING WILL HAVE TO WORK TO SATURATE LOWER LEVELS ACROSS
IL/IN TODAY. WITH STRONGEST WARM ADVECTION AND JET DYNAMICS EXPECTED
TO PROVIDE THE BEST FORCING THIS MORNING...BAND OF SNOW SHOULD HAVE
A HARDER TIME PRODUCING MODERATE SNOW FARTHER SOUTHEAST INTO IL AND
NORTHWEST IN.
A FEW REPORTS FROM NORTHEAST IA OF 3-5 INCH SNOWFALL AMOUNTS WITH
INITIAL STRONG BANDING EARLY THIS MORNING...THOUGH WITH FORCING
WEAKENING SOMEWHAT WITH TIME AND DRY LOW-LEVELS TO OVERCOME WOULD
EXPECT AMOUNTS TO TAPER QUICKLY INTO THE LOT CWA. BASED ON RADAR
TRENDS THROUGH THE MORNING...AND SOME WEB CAM IMAGERY FROM AREAS
ALONG AND NORTH OF RFD-UGN WHERE A FEW TENTHS OF ACCUM ALREADY HAS
OCCURRED...HAVE BUMPED SNOWFALL AMOUNTS A BIT TO AROUND AN INCH
ACROSS NORTHERN PARTS OF THE NORTHERN TIER COUNTIES...TO LESS THAN A
HALF INCH FROM ROUGHLY I-88 SOUTH.
RATZER
//PREV DISCUSSION...
323 AM CST
WITH NOVEMBER LOOKING TO FINISH WITH CONTINUED BELOW NORMAL
TEMPERATURES DURING ITS FINAL WEEK WITH LITTLE IN THE WAY OF SHARP
THERMAL CHANGES...THE PRIMARY FOCUS OF THE FORECAST WAS ON THE LIGHT
SNOW EVENT TODAY AND THEN THE LAKE EFFECT SNOW POTENTIAL INTO
NORTHWEST INDIANA TUESDAY NIGHT AND WEDNESDAY.
SOMEWHAT SPLIT UPPER FLOW IS IN PLACE ACROSS THE CENTRAL U.S. THIS
MONDAY WITH A QUICKLY-MOVING TROUGH ACROSS ONTARIO DIVING INTO THE
GREAT LAKES BY AFTERNOON...AND A CLOSED LOW ACROSS THE TEXAS
PANHANDLE BRINGING RARE NOVEMBER WINTER WEATHER HEADLINES TO THE
SOUTHERN PLAINS. OUR FORECAST AREA BASICALLY FALLS BETWEEN THESE TWO
SYSTEMS TODAY AND AS A RESULT THERE IS A VOID OF ANY OVERLY STRONG
FORCING OVERHEAD. ISENTROPIC ASCENT AND SATURATION WITHIN THE WSW
FLOW ALOFT THIS MORNING LOOKS TO BE THE PRIMARY CONTRIBUTOR TO
PRECIPITATION GENERATION...ALTHOUGH DRY LOW-LEVELS MAY KEEP IT
FLURRIES THROUGH MID TO LATE MORNING OVER CHICAGO. AN AXIS OF
FRONTOGENESIS CENTERED TO THE NORTHWEST OF THE AREA FROM EASTERN IA
INTO SOUTHERN WI THROUGH ~10 AM ON THE RAP AND LOCAL ARW MAY RESULT
IN BETTER SNOWFALL CLIPPING THE ROCKFORD AREA THIS MORNING...AND
CONCEIVABLY COULD SEE AN INCH BECAUSE OF THAT BUT THAT WOULD SEEM
THE MAXIMUM. AS THE SUBTLE FORCING AND MID-LEVEL SATURATION EVOLVES
EAST INTO THE AFTERNOON...PERIODS OF LIGHT SNOW WILL LIKELY RESULT
IN ONE HALF INCH OR LESS FOR MOST COMMUNITIES...AND NAMELY NORTH OF
I-80. WHILE NOT THE MOST IDEAL SYNOPTIC SETUP FOR FREEZING
DRIZZLE...THERE ARE SOME SIGNS ON GUIDANCE THAT AS ICE INTRODUCTION
IS LOST DURING THE MID TO LATE AFTERNOON THAT THERE MAY BE A BRIEF
WINDOW FOR THIS. ASCENT LOOKS WEAK AND CLOUD BASES LOOK HIGH FOR
THAT TO OCCUR THOUGH...SO CONTINUE TO NOT MENTION IN FORECAST.
THE AMOUNT OF CLOUD COVER TODAY WILL ONLY ALLOW TEMPERATURES TO RISE
BY ADVECTION...AND THAT WILL BE MEAGER AT THE SURFACE. SO MAINTAIN
HIGHS MAINLY IN THE LOWER 30S...WHICH WOULD RESULT IN THE THIRD
STRAIGHT DAY OF DOUBLE DIGIT DEPARTURES BELOW NORMAL.
A SECOND MORE ROBUST NORTHERN STREAM WAVE...THAT ACTUALLY LOOKS TO
BE A CLOSED SUB 520DM H5 LOW...WILL DROP INTO THE GREAT LAKES ON
TUESDAY. A FAIRLY DEEP PV ANOMALY IS SEEN WITH THIS ALONG WITH H5
TEMPS DOWN TO NEAR -30C...WHICH COME BARRELING INTO THE FORECAST
AREA BY LATE AFTERNOON INTO THE EVE TUESDAY ON THE GUIDANCE SUITE.
AN ASSOCIATED SURFACE COLD FRONT LOOKS TO STEEPEN LAPSE RATES AND
COULD SUPPORT SOME SNOW SHOWERS. CERTAINLY SOME FLURRIES LOOK TO BE
PRESENT INTO TUESDAY NIGHT. LOWS THAT NIGHT LOOK TO RETURN TO THE
MID AND POSSIBLY EVEN LOWER TEENS IN OUTLYING LOCATIONS.
MORE OF A CONCERN IS TURNING TO A POTENTIAL PLOWABLE SNOW FROM LAKE
EFFECT GENERATION INTO NORTHWEST INDIANA TUESDAY NIGHT INTO THE
BUSIEST TRAVEL DAY OF THE YEAR ON WEDNESDAY. THERE REMAINS MODEL
DIFFERENCES ON HOW QUICKLY THE AFOREMENTIONED SOUTHERN PLAINS UPPER
LOW AND THIS GREAT LAKES LOW PHASE. BUT OVERALL THE FLOW ACROSS LAKE
MI SHOULD BECOME STIFF AND NORTHERLY BY LATER TUESDAY NIGHT. THERE
ARE EVEN SIGNS ON SOME HIGH RESOLUTION MODELS...INCLUDING OUR LOCAL
ARW...OF MESO-LOW DEVELOPMENT TRANSLATING SOUTH ACROSS THE LAKE ON
TUESDAY NIGHT. CONFIDENCE ON SUCH A FEATURE IS LOW AT THIS
POINT...AS IS WHETHER THERE WILL EXIST A FOCUSED BAND OR JUST
WIDESPREAD SHOWERS OFF THE LAKE. BUT CONFIDENCE IS HIGH THERE WILL
BE AT LEAST SNOW SHOWERS INTO NORTHWEST INDIANA GIVE THE FORECAST
TRAJECTORIES...STEEP LOW-LEVEL LAPSE RATES...LAKE-INDUCED CAPE OF
AROUND 500 J/KG...AND EQUILIBRIUM LEVELS FORECAST AROUND 9000 FT.
THESE INDICES ACTUALLY INDICATE SOMEWHERE COULD GET A ROBUST SNOW
EVENT WITH HEAVY RATES WHICH WOULD IMPACT WEDNESDAY TRAVEL. IN
ADDITION...USING THE CIPS ANALOGS INDICATES A FAIRLY STRONG
CORRELATED EVENT FOR 850MB TEMPERATURES AND LOW-LEVEL WIND FLOW ON
11/21/08 AND THAT PRODUCED OVER 8 INCHES JUST EAST OF THE AREA. AT
THIS TIME HAVE CONTINUED THE TREND OF PREVIOUS SHIFT IN INCREASING
POPS ACROSS PORTER AND EASTERN LAKE COUNTIES.
BEYOND THERE WAS LITTLE CHANGE TO THE FORECAST AS THE HOLIDAY ITSELF
LOOKS QUIET ACROSS THE AREA WITH GRADUALLY BUILDING HEIGHTS AND
SURFACE HIGH PRESSURE. A QUASI-ZONAL PATTERN IS FAVORED ON LONG
RANGE DETERMINISTIC MODELS AND ENSEMBLES...WHICH WOULD FAVOR A
GRADUAL MODERATION TO NEAR NORMAL FOR THE FIRST DAY OF
METEOROLOGICAL WINTER ON SUNDAY.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* GUSTY SOUTHWEST WINDS THROUGH LATE AFTERNOON.
* PERIODS OF LIGHT SNOW THROUGH MID TO LATE AFTERNOON WITH
PERIODS OF MVFR TO IFR VIS AND MVFR CIGS LIKELY.
* MVFR CIGS TO PERSIST UNTIL LATE TONIGHT.
KREIN
//DISCUSSION...UPDATED 18Z...
MAIN CONCERNS FOR THE REMAINDER OF THE AFTERNOON WILL FOCUS ON
IMPACTS OF LIGHT SNOW AS WELL AS GUSTY SWLY WINDS.
AT THE CURRENT TIME...A BAND OF LIGHT WARM ADVECTION SNOW IS
SAGGING SWD THROUGH NRN IL AND WILL SOON MOVE INTO NWRN INDIANA.
SOUTH OF THE BAND...SCT UNORGANIZED AREAS OF LIGHT SNOW ARE ALSO
MOVING THROUGH THE AREA. THE LATEST RADAR TRENDS INDICATE THAT THE
SNOW BAND IS BECOMING A LITTLE LESS ORGANIZED AS IT SAGS TO THE
SOUTH...BUT STILL EXPECT A PERIOD OF SNOW TO IMPACT THE TERMINALS.
WHILE THE SNOW IS RELATIVELY LIGHT AND ACCUMULATIONS GENERALLY NOT
A MAJOR CONCERN AT THE TERMINALS...THE BIGGEST IMPACT WILL BE ON
VISIBILITY DUE TO THE STRONG...GUSTY WINDS. SO...EXPECT A PERIOD
OF ABOUT 2 HRS WHERE THE SNOWFALL RATE SILL BE HIGH
ENOUGH...COMBINED WITH THE STRONG WINDS TO REDUCE VISIBILITY TO
1-2SM. AND THE MAIN BAND OF SNOW SAGS SOUTH OF THE TERMINALS INTO
CNTRL IL/IN...THERE SHOULD STILL BE SOME LIGHT SNOW FALLING...BUT
GENERALLY VISIBILITY SHOULD RETURN TO VFR LEVELS. HOWEVER...MVFR
CIGS SHOULD PERSIST WELL INTO THE EVENING AND LATE NIGHT HOURS AS
COOLER AIR WRAPS AROUND A DEEP LOW PRESSURE SYSTEM TRACKING
THROUGH THE UPPER GREAT LAKES. WITH THE AREA BETWEEN AN
APPROACHING COLD FRONT ASSOCIATED WITH THE LOW TO THE NORTH AND
HIGH PRESSURE SITTING OVER THE MID ATLANTIC REGION...A SWLY
GRADIENT WILL REMAIN IN PLACE UNTIL THE FRONT SWEEPS THROUGH THE
REGION. LATEST MODEL GUIDANCE SUGGESTS THAT THE FRONT WILL MOVE
THROUGH NRN IL/IN BY LATE TOMORROW MORNING...AT WHICH TIME WINDS
WILL QUICKLY SHIFT FROM SWLY TO NWLY.
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH CONFIDENCE IN WIND TRENDS.
* MEDIUM CONFIDENCE DURATION OF MVFR AND IFR VIS ASSOCIATED WITH
WIND DRIVEN SNOW.
* MEDIUM TO HIGH CONFIDENCE IN CIG TRENDS.
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...
TUESDAY NIGHT...FLURRIES IN THE EVENING WITH MVFR CIGS LIFTING TO
VFR.
WEDNESDAY...LAKE EFFECT MVFR CIGS PSBL.
THURSDAY AND FRIDAY...VFR.
SATURDAY...MVFR CIGS PSBL OVERNIGHT.
SUNDAY...MVFR CIGS PSBL
KJB
&&
.MARINE...
206 AM CST
A VERY ACTIVE WEATHER PATTERN WILL CONTINUE ACROSS THE GREAT LAKES
THROUGH MID WEEK. THE CURRENT GALE EVENT IS WELL UNDERWAY WITH
SEVERAL REPORTS OF 40+ KT WINDS...ESPECIALLY ACROSS THE NORTHERN
HALF OF THE LAKE. THESE GALES WILL CONTINUE THROUGH AT LEAST THE MID
AFTERNOON HOURS TODAY AS A AN AREA OF LOW PRESSURE TRACKS EASTWARD
ACROSS SOUTHERN ONTARIO. THE WINDS WILL GRADUALLY ABATE INTO THIS
EVENING. THE CURRENT GALE HEADLINE MAY BE ALOUD TO EXPIRE A FEW
HOURS EARLIER THAN THE CURRENT 9 PM DEADLINE. HOWEVER...AT THIS
POINT I WILL LEAVE THE HEADLINE TIMING ALONE.
THE NEXT ISSUE WILL BE LATER TUESDAY THROUGH MUCH OF WEDNESDAY. A
STRONG STORM SYSTEM IS EXPECTED TO MOVE UP THE EAST COAST DURING
THIS TIME...AND AS HIGH PRESSURE BUILDS IN ACROSS THE MISSOURI
VALLEY CONDITIONS WILL BECOME FAVORABLE FOR A PERIOD OF NORTHERLY
GALES UP TO 35 TO 40 KT. THIS LOOKS TO BE THE MOST PRONOUNCED ACROSS
SOUTHERN LAKE MICHIGAN...AND ANY LAKE EFFECT BANDS OF SNOW THAT
DEVELOP DURING THIS TIME COULD LEAD ALSO EVEN LEAD TO SOME LOCALLY
HIGH WINDS IN EXCESS OF 40 KT. IT APPEARS TO BE A GOOD BET THAT A
GALE HEADLINE WILL BE NEEDED DURING THIS TIME. I THREW AROUND THE
IDEA OF HOSTING A GALE WATCH FOR THIS PERIOD...BUT DUE TO THE FACT
IT IS STILL FAR ENOUGH OUT...I HAVE DECIDED TO LET THE CURRENT
GALE HEADLINES END PRIOR TO THE ISSUANCE OF A NEW HEADLINE.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 PM MONDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 9 PM MONDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1040 AM CST MON NOV 25 2013
.DISCUSSION...
1040 AM CST
FOR MORNING UPDATE...
HAVE BUMPED SNOWFALL AMOUNTS JUST A BIT...TO AROUND 1 INCH...ALONG
THE WI/IL STATE LINE. OTHERWISE...ONLY MINOR TWEAKS TO NEAR TERM OF
GOING FORECAST.
MORNING WATER VAPOR IMAGERY AND 12Z UPPER AIR ANALYSIS DEPICT FAIRLY
STRONG MID-LEVEL SHORT WAVE TROUGH PROPAGATING ACROSS THE UPPER
MIDWEST AND NORTHERN GREAT LAKES REGION. MAIN AREA OF SURFACE LOW
PRESSURE WAS NORTH OF LAKE SUPERIOR...WHILE AN AREA OF ENHANCED LOW
LEVEL WARM ADVECTION WAS OCCURRING ACROSS IOWA...SOUTHEAST
MINNESOTA...WISCONSIN AND FAR NORTH/NORTHWEST ILLINOIS. ISENTROPIC
ASCENT AND MOISTURE ADVECTION WAS PRODUCING TOP-DOWN SATURATION IN A
NARROW CORRIDOR FROM DSM-DBQ-MKE...WITH LIGHT SNOW LOWERING
VISIBILITY TO 1/2 MILE IN SOME SPOTS ACROSS FAR SOUTHERN WI.
CONSIDERABLE DRY AIR BELOW 800-700 MB IN DVN AND ILX 12Z...WHICH
INDICATES FORCING WILL HAVE TO WORK TO SATURATE LOWER LEVELS ACROSS
IL/IN TODAY. WITH STRONGEST WARM ADVECTION AND JET DYNAMICS EXPECTED
TO PROVIDE THE BEST FORCING THIS MORNING...BAND OF SNOW SHOULD HAVE
A HARDER TIME PRODUCING MODERATE SNOW FARTHER SOUTHEAST INTO IL AND
NORTHWEST IN.
A FEW REPORTS FROM NORTHEAST IA OF 3-5 INCH SNOWFALL AMOUNTS WITH
INITIAL STRONG BANDING EARLY THIS MORNING...THOUGH WITH FORCING
WEAKENING SOMEWHAT WITH TIME AND DRY LOW-LEVELS TO OVERCOME WOULD
EXPECT AMOUNTS TO TAPER QUICKLY INTO THE LOT CWA. BASED ON RADAR
TRENDS THROUGH THE MORNING...AND SOME WEB CAM IMAGERY FROM AREAS
ALONG AND NORTH OF RFD-UGN WHERE A FEW TENTHS OF ACCUM ALREADY HAS
OCCURRED...HAVE BUMPED SNOWFALL AMOUNTS A BIT TO AROUND AN INCH
ACROSS NORTHERN PARTS OF THE NORTHERN TIER COUNTIES...TO LESS THAN A
HALF INCH FROM ROUGHLY I-88 SOUTH.
RATZER
&&
.PREV DISCUSSION...
323 AM CST
WITH NOVEMBER LOOKING TO FINISH WITH CONTINUED BELOW NORMAL
TEMPERATURES DURING ITS FINAL WEEK WITH LITTLE IN THE WAY OF SHARP
THERMAL CHANGES...THE PRIMARY FOCUS OF THE FORECAST WAS ON THE LIGHT
SNOW EVENT TODAY AND THEN THE LAKE EFFECT SNOW POTENTIAL INTO
NORTHWEST INDIANA TUESDAY NIGHT AND WEDNESDAY.
SOMEWHAT SPLIT UPPER FLOW IS IN PLACE ACROSS THE CENTRAL U.S. THIS
MONDAY WITH A QUICKLY-MOVING TROUGH ACROSS ONTARIO DIVING INTO THE
GREAT LAKES BY AFTERNOON...AND A CLOSED LOW ACROSS THE TEXAS
PANHANDLE BRINGING RARE NOVEMBER WINTER WEATHER HEADLINES TO THE
SOUTHERN PLAINS. OUR FORECAST AREA BASICALLY FALLS BETWEEN THESE TWO
SYSTEMS TODAY AND AS A RESULT THERE IS A VOID OF ANY OVERLY STRONG
FORCING OVERHEAD. ISENTROPIC ASCENT AND SATURATION WITHIN THE WSW
FLOW ALOFT THIS MORNING LOOKS TO BE THE PRIMARY CONTRIBUTOR TO
PRECIPITATION GENERATION...ALTHOUGH DRY LOW-LEVELS MAY KEEP IT
FLURRIES THROUGH MID TO LATE MORNING OVER CHICAGO. AN AXIS OF
FRONTOGENESIS CENTERED TO THE NORTHWEST OF THE AREA FROM EASTERN IA
INTO SOUTHERN WI THROUGH ~10 AM ON THE RAP AND LOCAL ARW MAY RESULT
IN BETTER SNOWFALL CLIPPING THE ROCKFORD AREA THIS MORNING...AND
CONCEIVABLY COULD SEE AN INCH BECAUSE OF THAT BUT THAT WOULD SEEM
THE MAXIMUM. AS THE SUBTLE FORCING AND MID-LEVEL SATURATION EVOLVES
EAST INTO THE AFTERNOON...PERIODS OF LIGHT SNOW WILL LIKELY RESULT
IN ONE HALF INCH OR LESS FOR MOST COMMUNITIES...AND NAMELY NORTH OF
I-80. WHILE NOT THE MOST IDEAL SYNOPTIC SETUP FOR FREEZING
DRIZZLE...THERE ARE SOME SIGNS ON GUIDANCE THAT AS ICE INTRODUCTION
IS LOST DURING THE MID TO LATE AFTERNOON THAT THERE MAY BE A BRIEF
WINDOW FOR THIS. ASCENT LOOKS WEAK AND CLOUD BASES LOOK HIGH FOR
THAT TO OCCUR THOUGH...SO CONTINUE TO NOT MENTION IN FORECAST.
THE AMOUNT OF CLOUD COVER TODAY WILL ONLY ALLOW TEMPERATURES TO RISE
BY ADVECTION...AND THAT WILL BE MEAGER AT THE SURFACE. SO MAINTAIN
HIGHS MAINLY IN THE LOWER 30S...WHICH WOULD RESULT IN THE THIRD
STRAIGHT DAY OF DOUBLE DIGIT DEPARTURES BELOW NORMAL.
A SECOND MORE ROBUST NORTHERN STREAM WAVE...THAT ACTUALLY LOOKS TO
BE A CLOSED SUB 520DM H5 LOW...WILL DROP INTO THE GREAT LAKES ON
TUESDAY. A FAIRLY DEEP PV ANOMALY IS SEEN WITH THIS ALONG WITH H5
TEMPS DOWN TO NEAR -30C...WHICH COME BARRELING INTO THE FORECAST
AREA BY LATE AFTERNOON INTO THE EVE TUESDAY ON THE GUIDANCE SUITE.
AN ASSOCIATED SURFACE COLD FRONT LOOKS TO STEEPEN LAPSE RATES AND
COULD SUPPORT SOME SNOW SHOWERS. CERTAINLY SOME FLURRIES LOOK TO BE
PRESENT INTO TUESDAY NIGHT. LOWS THAT NIGHT LOOK TO RETURN TO THE
MID AND POSSIBLY EVEN LOWER TEENS IN OUTLYING LOCATIONS.
MORE OF A CONCERN IS TURNING TO A POTENTIAL PLOWABLE SNOW FROM LAKE
EFFECT GENERATION INTO NORTHWEST INDIANA TUESDAY NIGHT INTO THE
BUSIEST TRAVEL DAY OF THE YEAR ON WEDNESDAY. THERE REMAINS MODEL
DIFFERENCES ON HOW QUICKLY THE AFOREMENTIONED SOUTHERN PLAINS UPPER
LOW AND THIS GREAT LAKES LOW PHASE. BUT OVERALL THE FLOW ACROSS LAKE
MI SHOULD BECOME STIFF AND NORTHERLY BY LATER TUESDAY NIGHT. THERE
ARE EVEN SIGNS ON SOME HIGH RESOLUTION MODELS...INCLUDING OUR LOCAL
ARW...OF MESO-LOW DEVELOPMENT TRANSLATING SOUTH ACROSS THE LAKE ON
TUESDAY NIGHT. CONFIDENCE ON SUCH A FEATURE IS LOW AT THIS
POINT...AS IS WHETHER THERE WILL EXIST A FOCUSED BAND OR JUST
WIDESPREAD SHOWERS OFF THE LAKE. BUT CONFIDENCE IS HIGH THERE WILL
BE AT LEAST SNOW SHOWERS INTO NORTHWEST INDIANA GIVE THE FORECAST
TRAJECTORIES...STEEP LOW-LEVEL LAPSE RATES...LAKE-INDUCED CAPE OF
AROUND 500 J/KG...AND EQUILIBRIUM LEVELS FORECAST AROUND 9000 FT.
THESE INDICES ACTUALLY INDICATE SOMEWHERE COULD GET A ROBUST SNOW
EVENT WITH HEAVY RATES WHICH WOULD IMPACT WEDNESDAY TRAVEL. IN
ADDITION...USING THE CIPS ANALOGS INDICATES A FAIRLY STRONG
CORRELATED EVENT FOR 850MB TEMPERATURES AND LOW-LEVEL WIND FLOW ON
11/21/08 AND THAT PRODUCED OVER 8 INCHES JUST EAST OF THE AREA. AT
THIS TIME HAVE CONTINUED THE TREND OF PREVIOUS SHIFT IN INCREASING
POPS ACROSS PORTER AND EASTERN LAKE COUNTIES.
BEYOND THERE WAS LITTLE CHANGE TO THE FORECAST AS THE HOLIDAY ITSELF
LOOKS QUIET ACROSS THE AREA WITH GRADUALLY BUILDING HEIGHTS AND
SURFACE HIGH PRESSURE. A QUASI-ZONAL PATTERN IS FAVORED ON LONG
RANGE DETERMINISTIC MODELS AND ENSEMBLES...WHICH WOULD FAVOR A
GRADUAL MODERATION TO NEAR NORMAL FOR THE FIRST DAY OF
METEOROLOGICAL WINTER ON SUNDAY.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* GUSTY SOUTHWEST WINDS TODAY.
* PERIODS OF LIGHT SNOW LIKELY BEGINNING EARLY AFTERNOON THROUGH
MID TO LATE AFTERNOON WITH PERIODS OF MVFR TO IFR VIS AND MVFR
CIGS POSSIBLE.
* HAVE PUSHED BACK TIMING OF SNOW ONSET BY AN HOUR IN THE TAFS.
KREIN
//DISCUSSION...UPDATED 12Z...
THE MAIN FORECAST CONCERNS THIS MORNING CONTINUE TO REVOLVE AROUND
THE LIGHT SNOW EXPECTED ACROSS THE TERMINALS TODAY...ALONG WITH
THE STRONG SOUTHWESTERLY WINDS.
A STRONG PRESSURE GRADIENT IS SETTING UP ACROSS THE AREA EARLY THIS
MORNING IN ASSOCIATION WITH LOW PRESSURE ACROSS SOUTHERN ONTARIO AND
HIGH PRESSURE ACROSS THE SOUTHEASTERN CONUS. THIS WILL CONTINUE TO
SUPPORT GUSTY WINDS THROUGH THE DAY. OVERALL WINDS STILL APPEAR TO
BE SOUTHWESTERLY AROUND 15 TO 17 KT WITH GUSTS UP TO 25 TO 28 KT.
THE OTHER CONCERN IS THAT FOR LIGHT SNOW. SNOW IS BEGINNING TO FALL
ACROSS PORTIONS OF IOWA AND INTO NORTHWESTERN ILLINOIS THIS
MORNING. THIS ACTIVITY WILL TAKE SOME TIME TO MOVE ACROSS
NORTHEASTERN ILLINOIS AS THE LOWER LEVELS ARE STILL FAIRLY DRY.
HOWEVER...WITH TIME THIS MORNING THE LOWER LEVELS WILL MOISTEN TO
ALLOW SNOW TO START AFTER 16 UTC AT THE EASTERN TERMINALS AND A
COUPLE HOURS SOONER AT KRFD. OVERALL...THIS WILL NOT BE A BIG
SNOW MAKER. THERE WILL BE ABOUT A 4 TO 6 HOUR WINDOW FOR SOME
LIGHT SNOW. VISIBILITIES IN THE SNOW COULD DROP DOWN AROUND 2
MILES FOR A PERIOD AND SOME LIGHT ACCUMULATIONS UP TO A HALF INCH
ARE POSSIBLE...ESPECIALLY AT KRFD. THE SNOW CHANCES WILL END QUICKLY
BY MID TO LATE AFTERNOON AS DRYER AIR FILTERS IN ACROSS THE AREA.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* HIGH CONFIDENCE IN WINDS.
* MEDIUM CONFIDENCE IN PERIODS OF LIGHT SNOW WITH MVFR TO IFR VIS
AND MVFR CIGS.
* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...
TUESDAY NIGHT...FLURRIES IN THE EVENING WITH MVFR CIGS LIFTING TO
VFR.
WEDNESDAY...LAKE EFFECT MVFR CIGS PSBL.
THURSDAY AND FRIDAY...VFR.
SATURDAY...MVFR CIGS PSBL OVERNIGHT.
SUNDAY...MVFR CIGS PSBL
KJB
&&
.MARINE...
206 AM CST
A VERY ACTIVE WEATHER PATTERN WILL CONTINUE ACROSS THE GREAT LAKES
THROUGH MID WEEK. THE CURRENT GALE EVENT IS WELL UNDERWAY WITH
SEVERAL REPORTS OF 40+ KT WINDS...ESPECIALLY ACROSS THE NORTHERN
HALF OF THE LAKE. THESE GALES WILL CONTINUE THROUGH AT LEAST THE MID
AFTERNOON HOURS TODAY AS A AN AREA OF LOW PRESSURE TRACKS EASTWARD
ACROSS SOUTHERN ONTARIO. THE WINDS WILL GRADUALLY ABATE INTO THIS
EVENING. THE CURRENT GALE HEADLINE MAY BE ALOUD TO EXPIRE A FEW
HOURS EARLIER THAN THE CURRENT 9 PM DEADLINE. HOWEVER...AT THIS
POINT I WILL LEAVE THE HEADLINE TIMING ALONE.
THE NEXT ISSUE WILL BE LATER TUESDAY THROUGH MUCH OF WEDNESDAY. A
STRONG STORM SYSTEM IS EXPECTED TO MOVE UP THE EAST COAST DURING
THIS TIME...AND AS HIGH PRESSURE BUILDS IN ACROSS THE MISSOURI
VALLEY CONDITIONS WILL BECOME FAVORABLE FOR A PERIOD OF NORTHERLY
GALES UP TO 35 TO 40 KT. THIS LOOKS TO BE THE MOST PRONOUNCED ACROSS
SOUTHERN LAKE MICHIGAN...AND ANY LAKE EFFECT BANDS OF SNOW THAT
DEVELOP DURING THIS TIME COULD LEAD ALSO EVEN LEAD TO SOME LOCALLY
HIGH WINDS IN EXCESS OF 40 KT. IT APPEARS TO BE A GOOD BET THAT A
GALE HEADLINE WILL BE NEEDED DURING THIS TIME. I THREW AROUND THE
IDEA OF HOSTING A GALE WATCH FOR THIS PERIOD...BUT DUE TO THE FACT
IT IS STILL FAR ENOUGH OUT...I HAVE DECIDED TO LET THE CURRENT
GALE HEADLINES END PRIOR TO THE ISSUANCE OF A NEW HEADLINE.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 PM MONDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 9 PM MONDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS GAYLORD MI
1257 PM EST MON NOV 25 2013
.SYNOPSIS...
ISSUED AT 449 AM EST MON NOV 25 2013
WINTRY CONDITIONS WILL BE PREVALENT ACROSS NORTHERN MICHIGAN THROUGH
THE THANKSGIVING HOLIDAY WEEK...WITH SEVERAL WEAKER WEATHER SYSTEMS
DELIVERING REPEATED SHOTS OF BOTH SYSTEM AND LAKE EFFECT SNOW. THE
FIRST WILL ARRIVE THIS MORNING...AS LOW PRESSURE TRACKS NEAR JAMES
BAY...BRINGING A ROUND OF SNOW TO MUCH OF NORTHWEST LOWER AND
EASTERN UPPER. A COLD FRONT WILL GRADUALLY WORK THROUGH THE REGION
LATER TUESDAY...BRINGING RENEWED COLD CONDITIONS ALONG WITH MORE
LAKE EFFECT SNOW. THAT GENERAL TREND WILL CONTINUE INTO THANKSGIVING
DAY...BEFORE QUIET WEATHER MAKES A RETURN TOWARD NEXT WEEKEND.
&&
.UPDATE...
ISSUED AT 1239 PM EST MON NOV 25 2013
AS EARLIER ANTICIPATED...DEEPER MOISTURE IS IN THE PROCESS OF
EXITING THE AREA...AND THIS HAS CAUSED SNOW SHOWER ACTIVITY TO
DIMINISH QUITE RAPIDLY PAST 1-2 HRS. IN GENERAL...1-3 INCHES OF
SNOW HAS FALLEN THUS FAR ACROSS NW LOWER AND PARTS OF ERN UPPER.
GIVEN MODEST OVER-WATER INSTABILITY...DON/T EXPECT MUCH MORE THAN
SCATTERED SNOW SHOWERS /WITH LITTLE NEW ACCUMULATION/ UNTIL
MOISTURE DEEPENS BACK UP A BIT EARLY THIS EVENING. WILL UPDATE
FORECAST TO REFLECT THIS TREND.
SOME CONCERN THAT SHALLOWING MOISTURE PROFILE (TO WARMER THAN
ABOUT -8C) MAY SUPPORT SOME DRIZZLE OR FREEZING DRIZZLE THIS
AFTERNOON (DEPENDING ON LOCATION AND SURFACE TEMPERATURE). SOME
OBS ALONG THE LAKE MICHIGAN SHORELINE ARE SHOWING MVFR VSBYS
WITHOUT SNOW BEING REPORTED. 88D ALSO SHOWING A BROADENING AREA OF
WEAK RADAR RETURNS - POSSIBLY INDICATIVE OF DRIZZLE. WILL MONITOR
FOR THIS POTENTIAL WEATHER/HAZARD.
UPDATE ISSUED AT 930 AM EST MON NOV 25 2013
QUICK SHOT OF LAKE ENHANCED SNOW CONTINUES TO IMPACT EAST UPPER
AND NW LOWER THIS MORNING...AS SHORT WAVE AND ASSOCIATED DEEP MOISTURE
SWINGS THROUGH THE REGION. OVERALL LAKE CONTRIBUTION NOT
GREAT...WITH WATER TEMPS NEAR +8C AND 850 MB TEMPS AROUND -6C
(IDEA FURTHER SUPPORTED BY 12Z APX/GRB SOUNDINGS).
THAT SAID...COMBINATION OF ONGOING SNOW BURST AND CONTINUED GUSTY
WINDS WILL STILL RESULT IN NEAR-ADVISORY CONDITIONS NEXT SEVERAL
HOURS WITH LOCALLY DIFFICULT TRAVEL. HOWEVER...AS DEEPER MOISTURE
DEPARTS AND ONLY MARGINAL LAKE CONTRIBUTIONS LINGER...SUSPECT A
MARKED DECREASE IN SNOW SHOWER INTENSITY EARLY THIS AFTERNOON. FOR
THIS REASON...EXPECT 2-4 INCH SNOW AMOUNTS /MAINLY NW LOWER/ TO
HOLD FOR THE DAY.
UPDATE ISSUED AT 629 AM EST MON NOV 25 2013
DEEP MOISTURE OUT AHEAD OF AN ADVANCING COLD FRONT IS STARTING TO
DEVELOP SNOWS ACROSS FAR NRN LAKE MICHIGAN AND THROUGH THE STRAITS
REGION. STILL DEFINITELY EXPECTING A RAPID PRODUCTION AND
INTENSIFICATION OF SNOWS IN A SW TO NE ORIENTED BAND...COMBINED
WITH VERY STRONG SW WIND GUSTS TO 50 MPH. THIS WILL BRING A PERIOD
OF MODERATE TO HEAVY SNOWS ACROSS MUCH OF NW LOWER AND EASTERN
SECTIONS OF CHIP/MACK COUNTIES THIS MORNING. ALREADY ISSUED THE
INITIAL SPS ALERTING OF RAPIDLY DEVELOPING HAZARDOUS DRIVING
CONDITIONS. FOLKS...PLEASE ALLOW EXTRA TIME TO REACH YOUR
DESTINATION. DID INCREASE SNOWFALL ACROSS AN AREAS SURROUNDING
LEELANAU COUNTY...WHERE A LONGER PERIOD OF SNOWS ARE EXPECTED THIS
MORNING. OTHERWISE...THE FORECAST IS IN GOOD SHAPE.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 449 AM EST MON NOV 25 2013
WELL...THAT WAS A NICE 12-ISH HOUR RESPITE FROM THE ACTIVE WEATHER.
NOW IT`S GAME ON ONCE AGAIN...WITH THE MAIN FORECAST ISSUES BEING OF
THE LAKE EFFECT/ENHANCEMENT VARIETY...ALONG WITH WIND ISSUES THROUGH
THE DAY TODAY. EARLY MORNING ANALYSIS PLACES VERY WEAK SHORTWAVE
RIDGE AXIS JUST TO THE EAST OF NORTHERN MICHIGAN...WITH DEEP AND
QUITE STRONG SOUTHWESTERLY FLOW WELL RAMPED UP ACROSS THE NORTHERN
LAKES IN ADVANCE OF ANOTHER STRONG UPPER WAVE QUICKLY AMPLIFYING
THROUGH SOUTHERN MANITOBA. INITIAL PUSH OF THAT WARM ADVECTION
EARLIER LED TO A BRIEF AXIS OF LIGHT SNOW MARCHING THROUGH
NORTHERN/EASTERN AREAS...WITH SECONDARY SURGE OF MUCH DEEPER AND
STRONGER ASCENT GOING INTO GRADUAL TOP-DOWN SATURATION OFF TO OUR
WEST AT THE MOMENT...AS EVIDENCED BY CEILINGS FALLING 5-8KFT OVER
THE PAST FEW HOURS. MEANWHILE...QUITE THE WINDY CONDITIONS HAVE
SHOWN UP RECENTLY AS CORE OF RATHER IMPRESSIVE 45-55 KNOT FLOW IS
ROLLING OVERHEAD...COMBINING WITH A REMNANT UNSTABLE AIRMASS ACROSS
THE LAKES TO PRODUCE SOME RATHER BEEFY WIND GUSTS PUSHING 50 MPH
ALONG THE LAKE MICHIGAN SHORE.
THE ABOVE MENTIONED WARM ADVECTION WILL BE IMPORTANT FOR OUR AREA
THIS MORNING...AS THE ADDED MOISTURE (FROM AN INITIALLY QUITE DRY
AIRMASS) GIVES A BIG BOOST OVER LAKE MICHIGAN. ALREADY SEEING THE
FIRST HINTS OF THIS RIGHT NOW...BUT THE THOUGHT IS THAT DEEPER
MOISTURE OVERRIDING THE LAKE WILL GO INTO THE RAPID PRODUCTION OF A
SOUTHWEST FLOW LAKE BAND THE NEXT FEW HOURS...WHICH WILL ULTIMATELY
GET PUNTED ONSHORE AS THE SHARP UPPER WAVE OVER MANITOBA WORKS
TOWARD OUR AREA. THESE TYPES OF SETUPS ALWAYS HAVE TROUBLE WRITTEN
ALL OVER THEM FROM AN IMPACT STANDPOINT...AS THERE SHOULD BE A
COUPLE HOUR WINDOW FOR SOME HEAVY SNOW TO FALL UP AND DOWN THE LAKE
MICHIGAN SHORELINE COUNTIES...AND PROBABLY EVEN FARTHER INLAND INTO
THE HIGHER TERRAIN WHERE UPSLOPE TYPICALLY WORKS ITS MAGIC IN SUCH A
SETUP. GIVEN WARMING THERMAL PROFILES...SNOW TO LIQUID RATIOS SHOULD
BE RATHER LOW...AS EVIDENCED BY A QUITE DEEP ISOTHERMAL LAYER AROUND
-6C PER FORECAST RAOBS...MAKING FOR MORE OF A GREASY/SLIPPERY SNOW.
THROW IN SOME QUITE GUSTY WINDS AND THE STAGE IS PROBABLY SET FOR A
PERIOD OF SLOPPY TRAVEL/LOW VSBYS ACROSS PRIMARILY NORTHWEST
LOWER...WITH A QUICK 2-3" OF SNOW EXPECTED TO FALL. LOCAL 4/12KM APX
WRF AND RECENT HRRR RUNS ARE EVEN MORE IMPRESSIVE...PAINTING AN AXIS
OF 0.4" OF LIQUID UP TOWARD CHARLEVOIX/EMMET/CHEBOYGAN/OTSEGO/ANTRIM
COUNTIES...WITH A SECONDARY MAXIMUM NEAR CADILLAC. GIVEN THE
EXPECTED LOWER RATIOS...SHOULDN`T SEE ACCUMULATION GET OUT OF
HAND...EVEN IF THE HIGHER QPF FORECASTS VERIFY. NOT SURE THIS WILL
BE WORTHY OF A WINTER WEATHER HEADLINE - PROBABLY MORE LIKE AN
SPS...ESPECIALLY CONSIDERING THE WORST CONDITIONS SHOULD OCCUR JUST
AFTER THE MORNING COMMUTE (MAINLY 9AM-1PM).
WINDS WILL SUBSIDE HEADING INTO THE AFTERNOON AS THE CORE OF
STRONGEST 950-900MB FLOW EXITS EAST...ALL WHILE DEEPER MOISTURE ALSO
STRIPS OUT. THAT LEAVES US IN MORE OF A LIGHT SNOW SHOWERS/SNIZZLE
REGIME FOR MUCH OF THE AFTERNOON AS SOUTHWEST FLOW CONTINUES BUT
WHILE CLOUD TOP TEMPS HOVER ONLY AROUND -8C. PROBABLY NOT LOOKING AT
MUCH ADDITIONAL ACCUMULATION FOR MOST AREAS THROUGH LATE AFTERNOON.
HOWEVER...MORE ISSUES SHOW UP BY EARLY EVENING WITH PERSISTENT HINTS
OF A STRONGER FRONTAL SNOW BAND BEING BROUGHT ASHORE INTO EASTERN
UPPER AS LOW PRESSURE NEARS THE SOUTHERN TIP OF JAMES BAY AND SWINGS
A COLD FRONT THROUGH THE EASTERN U.P. THAT FEATURE WILL IN ALL
LIKELIHOOD BECOME ABSORBED INTO THE LAKE AGGREGATE TROUGH OVER
EASTERN LAKE SUPERIOR...WITH PERHAPS EVEN A WEAK CIRCULATION CENTER
DEVELOPING IN RESPONSE TO YET ANOTHER STRONG UPPER WAVE ENTERING THE
ARROWHEAD OF MINNESOTA. THAT SETUP COULD LEAD TO ALL KINDS OF
MESOSCALE GARBAGE...BUT THE CLEAR SIGNAL IS FOR AN ENHANCED
CONVERGENCE BAND TO SKIRT FAR NORTHERN CHIPPEWA COUNTY...MAINLY
TOWARD PARADISE/WHITEFISH POINT...WITH MAYBE A COUPLE INCHES
POSSIBLE. FARTHER SOUTH...LOOKING LIKE PERSISTENT MORE NEBULOUS SNOW
SHOWERS WILL CONTINUE OVERNIGHT FOR SOUTHWEST FLOW AREAS ACROSS
NORTHWEST LOWER UP TOWARD DRUMMOND ISLAND. WAS A LITTLE CONCERNED
ABOUT SOME DRIZZLE POSSIBILITIES GIVEN INITIALLY SHALLOW NATURE OF
MOISTURE...BUT GRADUAL INTRUSION OF COLDER AIR ALOFT SHOULD FAVOR
ICE IN THE CLOUDS AS CLOUD TOP TEMPS END UP AROUND -12C BY 06Z. NO
MAJOR ACCUMULATION FORESEEN FOR NORTHERN LOWER OVERNIGHT.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 449 AM EST MON NOV 25 2013
A VERY ACTIVE AND RAPIDLY CHANGING WEATHER PATTERN WILL REMAIN
LOCKED IN ACROSS THE GREAT LAKES THROUGH THE THANKSGIVING HOLIDAY
WITH A SERIES OF SHORTWAVES AND SHOTS OF COLDER CANADIAN AIR
RESULTING IN A COUPLE OF ROUNDS OF LAKE EFFECT AND LAKE ENHANCED
SNOWFALL. THIS WILL ALSO PREVENT US FROM ANY SIGNIFICANT WARMING FOR
THE NEXT SEVERAL DAYS. A FAIRLY QUIET PERIOD OF WEATHER IS THEN
ANTICIPATED FOR FRIDAY THROUGH THE WEEKEND.
TUESDAY THROUGH WEDNESDAY NIGHT...A SIMILAR SET UP LIKE TODAY...IS
EXPECTED FOR TUESDAY WITH NEXT VIGOROUS SHORTWAVE...COLD FRONT AND
DEEPER MOISTURE ANTICIPATED TO MOVE IN ACROSS NRN MICHIGAN. THIS
TIME AROUND...WE WILL HAVE A BIT DEEPER INSTABILITY BUT LESS WIND.
WEST/WSW FLOW AHEAD OF THIS FRONT...H8 TEMPS COLDER IN THE -10C TO
-11C RANGE AND INVERSION HEIGHTS TO 7KFT WILL INCREASE TO NEAR 9KFT
WITH COLD ADVECTION THROUGH THE DAY...BUT A DRAMATIC SHIFT IN WINDS
TO OUT OF THE NNW INTO TUESDAY EVENING. THE MOST IMPRESSIVE LES
PARAMETERS ARE REALLY FOCUSED TUESDAY EVENING AFTER THE FLOW TURNS
NORTHERLY WITH DEEPEST INSTABILITY WITH PASSAGE OF UPPER TROUGH
AXIS/COLD AIR ALOFT. THIS WILL FOCUS THE BEST ACCUMULATION
POTENTIAL ACROSS THE GTV BAY REGION AND AREAS SOUTH...WHERE
ALSO...GUSTY WINDS COULD LEAD TO BLOWING AND DRIFTING ISSUES. A
CONSERVATIVE 3-6 INCHES OF SNOW WILL BE POSSIBLE IN THIS REGION
TUESDAY-TUESDAY NIGHT...LEADING TO THE MOST HAZARDOUS DRIVING
CONDITIONS EXPECTED IN THE LONG TERM PORTION OF THE FORECAST. THE
AIR MASS DRIES WITH LOWERING INVERSION HEIGHTS INTO
WEDNESDAY...HOWEVER CONTINUED COLD ADVECTION AND BEST FETCH INTO
GTV BAY WILL LEAD TO ANOTHER 1-2 INCHES OF SNOW THERE...WHILE
AMOUNTS ARE LESS IMPRESSIVE ELSEWHERE. FAR NE LOWER NEAR ROGERS
CITY/ALPENA AND OSCODA WILL SEE A SMATTERING OF 1 TO MAYBE 3 INCH
LOCAL AMOUNTS TUESDAY NIGHT INTO WEDNESDAY. WEDNESDAY
NIGHT...INVADING HIGHER PRESSURE AND LIGHTER WINDS FOR A LESSER
THREAT TO ANYTHING SIGNIFICANT IN THE SNOW DEPARTMENT.
HOWEVER...WILL HAVE TO KEEP AN EYE ON NEXT INCOMING SHORTWAVE AND
WARM ADVECTION OVER THE TOP OF THE REMAINING
INSTABILITY...ALTHOUGH MOST AREAS...LOOK TO HAVE A DISCONNECT FROM
THE MOISTURE AND ENHANCEMENT SEEDED FROM ALOFT. SLOWLY BACKING LOW
LEVEL WINDS WILL FOCUS ANY EMERGING THREAT OF RENEWED SNOW IN AND
AROUND LAKE MICHIGAN.
THANKSGIVING DAY AND NIGHT...THIS INCOMING WAVE IS RATHER WEAK
COMPARED TO IT`S PREDECESSORS....ALTHOUGH THE WARM ADVECTION/SEEDING
ALOFT DOES LOOK TO STILL HAVE SOME SORT OF ENHANCEMENT TO THE LAKE
EFFECT THROUGH THE HOLIDAY AND THURSDAY NIGHT. WINDS ARE EXPECTED TO
BE FAIRLY LIGHT...AND NOW SHIFTING ALL AROUND TO THE SW AS THIS
ENHANCEMENT PROCESS IN UNDERWAY...SPREADING SNOWS AROUND LAKE
MICHIGAN WITH LESS INLAND PENETRATION. THESE FINER DETAILS WILL
REALLY HAVE TO BE EXAMINED FURTHER OVER THE NEXT COUPLE OF DAYS TO
PROVIDE A MORE DETAILED HOLIDAY FORECAST. WIND DIRECTIONS AND SPEEDS
BEING THE MOST CRUCIAL...WHICH HAS A BIT OF UNCERTAINTY.
FRIDAY THROUGH SUNDAY...THIS WEAKER WAVE EXITS FRIDAY WITH SHALLOW
MID LEVEL RIDGING...AHEAD OF NEXT ADVERTISED SHORTWAVE ARRIVING
SATURDAY. A WEAK COLD FRONT LAYS ACROSS/WASHES OUT OVER NRN
MICHIGAN. COULD BE ONE LAST HOORAH OF SOME WEAKER LAKE EFFECT...BUT
THIS APPEARS TO BE THE LEAST OF CONCERN IN THE SERIES OF LAKE EFFECT
EVENTS. THIS MAINLY DUE TO THE CONTINUED LOW LEVEL WARM ADVECTION
AND GRADUAL EROSION OF THE OVERLAKE INSTABILITY. WILL HAVE RATHER
SMALL CHANCES FOR SNOW IN AND AROUND LAKE MICHIGAN IN THE SW FLOW
THAT PERSISTS INTO SUNDAY. TEMPERATURES WILL MODERATE BACK INTO THE
LOWER HALF OF THE 30S OVER THE WEEKEND.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1250 PM EST MON NOV 25 2013
LOW LEVEL MOISTURE WILL REMAIN WIDESPREAD THROUGH TUESDAY...WITH
PRIMARILY MVFR CEILINGS ACROSS NW LOWER MI (TVC/PLN/MBL)...AND VFR
CEILINGS NE LOWER MI (APN). THERE MAY BE A BRIEF PERIOD OF HIGHER
(VFR) CEILINGS TONIGHT...BUT NOT A HIGH CONFIDENCE OCCURRENCE.
OTHERWISE...SCATTERED SNOW SHOWERS WILL PERSIST DOWNWIND OF LAKE
MICHIGAN THROUGH TUESDAY. THE NEXT INCREASE IN LAKE SNOW IS
EXPECTED MIDDAY TUESDAY...AS COLDER AIR SWEEPS EWD ACROSS LAKE
MICHIGAN. WINDS WILL REMAIN BRISK FROM THE SOUTHWEST.
&&
.MARINE...
ISSUED AT 449 AM EST MON NOV 25 2013
A WINDY ONE OUT THERE TO START...WITH GALES FOR MOST OF THE WATERS.
THOSE WINDS WILL SUBSIDE LATER THIS AFTERNOON AND ESPECIALLY THIS
EVENING...THOUGH WILL REMAIN A BIT GUSTY IN THE 20-25 KNOT RANGE AS
IS TYPICAL FOR LATE NOVEMBER. WINDS WILL GRADUALLY COME AROUND TO
THE NORTHWEST ON TUESDAY AND THEN NORTH TUESDAY NIGHT AND
WEDNESDAY...WITH CONTINUED GUSTS OF 25-30 KNOTS EXPECTED. COULD SEE
A PERIOD OF GALES ON MAINLY LAKE MICHIGAN SOMETIME TUESDAY NIGHT...
BUT CONFIDENCE IN THAT IS LOW AT THIS TIME. HIGH PRESSURE WILL
FINALLY WIN THE BATTLE BY THURSDAY...WITH A RETURN TO A BRIEF PERIOD
OF MUCH LIGHTER WINDS OF THE 15 KNOTS OF LESS VARIETY.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...WIND ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR MIZ015-016-019-
020-025-031.
LH...GALE WARNING UNTIL 10 PM EST THIS EVENING FOR LHZ345>349.
LM...GALE WARNING UNTIL 10 PM EST THIS EVENING FOR LMZ323-341-342-
344>346.
LS...SMALL CRAFT ADVISORY UNTIL 10 PM EST THIS EVENING FOR LSZ321-322.
&&
$$
UPDATE...BS
SYNOPSIS...DL
SHORT TERM...DL
LONG TERM...SD
AVIATION...BS
MARINE...DL
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1200 PM EST MON NOV 25 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 516 AM EST MON NOV 25 2013
WV IMAGERY AND RUC ANALYSIS INDICATED WNW MID/UPPER LEVEL FLOW FROM
CNTRL CANADA THROUGH THE GREAT LAKES WITH ONE SHORTWAVE TROUGH FROM
NW ONTARIO INTO NW MN AND ANOTHER WELL TO THE NORTH MOVING INTO NRN
SASK. AT THE SFC...A TIGHT PRES GRADIENT PREVAILED ACROSS THE WRN
GREAT LAKES BTWN A 1000 MB LOW LOCATED JUST NORTH OF THUNDER BAY
ONTARIO AND A 1036 MB RIDGE OVER THE OH VALLEY. WITH THE STRONGEST
PRES FALLS MOVING TO THE NE OF LAKE SUPERIOR...VERY STRONG SW WINDS
PERSISTED ACROSS WRN LAKE SUPERIOR AND NRN LAKE MICHIGAN. WAA
LEADING TO INCREASING STABILITY HAS LIMITED MIXING OF 45-50 KNOT
925-850 MB WINDS TOWARD THE SFC EXCEPT OVER THE RELATIVELY WARM LAKE
MICHIGAN WATERS. GUSTS IN THE 35-40 KT RANGE PERSISTED FROM FAIRPORT
TO PORT INLAND WHERE A WIND ADVISORY WAS IN EFFECT. WINDS OVER
INLAND LOCATIONS AT ESC AND ISQ WERE ONLY GUSTING TO AROUND 25
KNOTS. RADAR INDICATED WEAK RETURNS...MAINLY OVER THE ERN CWA...WITH
SOME PATCHY LIGHT SNOW OR FLURRIES SUPPORTED BY 700-300 QVECTOR CONV
AND ISENTROPIC LIFT AHEAD OF THE UPSTREAM SHRTWV.
TODAY...EXPECT WINDS TO SUBSIDE BY THE 15Z WIND ADVISORY EXPIRATION
TIME AS THE CORE OF THE STRONGEST 925-850 MB WINDS SHIFTS OFF TO THE
EAST. AS THE AREA OF LIGHT SNOW MOVES TO THE EAST...SOME LAKE
ENHANCEMENT MAY BE POSSIBLE WITH THE SW FLOW OFF OF LAKE MICHIGAN
BUT SHOULD REMAIN MAINLY TO THE SOUTH AND EAST OF THE CWA. OVER THE
KEWEENAW...AN AREA OF LOW LEVEL CONV AS WINDS VEER FROM SW TO W MAY
BRING A BRIEF PERIOD OF LAKE ENHANCED SNOW. HOWEVER...MID LEVEL
DRYING WITH THE DRY SLOT AND MARGINAL INSTABILITY WITH 850 MB TEMPS
AROUND -7C (LAKE SFC NEAR 4C) SUPPORTS ONLY CHANCE POPS WITH ANY
ACCUMULATIONS ONLY AMOUNTING TO A HALF INCH OR LESS. INCREASING
850-700 MB MOISTURE AND AND 850/700 MB TEMPS DROPPING TO -10C/-17C
WITH THE APPROACH OF THE SHRTWV WILL ALSO BRING AN INCREASE IN LAKE
ENHANCED SNOW INTO THE WEST AND THE ERN SHORELINE FROM PICTURED
ROCKS TO GRAND MARAIS.
TONIGHT...STRONGER CAA DROPPING 850 MB TEMPS TO AROUND -18C BOOSTING
LAKE INDUCED CAPES TO NEAR 700 J/KG ALONG WITH STRENGTHENING
CYCLONIC NW FLOW WILL BRING A FURTHER INCREASE IN LES INTO THE WEST.
THE HIGH RES MODELS OFFER A VARIETY OF SOLUTIONS AS TO WHERE THE
HEAVIER SNOW BANDS WILL FOCUS AND DELAY THE STRONGER VEERING WIND
SHIFT AND LOW LEVEL CONV BAND MOVING IN TIL AFT 12Z. ALTHOUGH
SEVERAL INDICATE THE GREATER SNOW POTENTIAL INTO THE KEWEENAW AND
IRONWOOD AREAS...CONFIDENCE IN IN HIGHLIGHTING ANY PARTICULAR
LOCATION IS LIMITED. SO...A GENERAL 2 TO 5 INCH FCST WAS INCLUDED
FOR MOST OF THE NW TO WNW FLOW SNOWBELTS IN THE WEST AS WELL AS
LOCATIONS NORTH OF M-28 EAST OF MUNISING.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 437 AM EST MON NOV 25 2013
EXTENT OF LAKE EFFECT SNOW AND SNOW AMOUNTS ALONG WITH THE NEED FOR
ANY ADVISORIES OR WARNINGS TUESDAY/TUESDAY NIGHT IS PRIMARY FOCUS.
IN LARGE SCALE...STRONG SHORTWAVE IN NORTHERN STREAM CURRENTLY OVER
NORTHERN MANTIOBA WILL BE CROSSING UPR MICHIGAN AND LK SUPERIOR ON
TUESDAY. NAM/GFS/ECMWF DECENT AGREEMENT WITH TIMING OF LARGER SCALE
IMPACTS AS THEY ALL SHOW H7-H5/H5-H3 Q-VECTOR CONVERGENCE INTO WESTERN
UPR MICHIGAN BEFORE 12Z TUESDAY SPREADING TO CNTRL CWA BY 18Z AND
EXITING EASTERN CWA BY 00Z WEDNESDAY. MAY SEE MINOR LGT SNOW EVEN
INTO SOUTH AS THE SHORTWAVE CROSSES THE REGION. BIGGEST IMPACT
THOUGH WILL BE ON LK EFFECT THAT BEGINS LATE TONIGHT. NAM AND GFS
FORECAST SOUNDINGS SHOW GOOD RESPONSE FM THE WAVE WITH INVERSION
HEIGHTS RISING ABOVE 5KFT LATE TONIGHT AND SPIKING UP TO 8-10KFT BY
MIDDAY TUESDAY. LAKE EQUILIBRIUM LEVELS INCREASE TO 13KFT AND LAKE
INDUCED CAPE VALUES CLIMB OVER 700J/KG AS H85 TEMPS FALL TO -17C TO
-20C BY TUESDAY NIGHT. SOUNDINGS ALSO INDICATE INCREASING MOISTURE
QUALITY TUESDAY INTO MOST OF TUESDAY NIGHT. SO...INSTABILITY AND
MOISTURE NOT THE ISSUE FOR MODERATE TO HEAVY SNOW. BOTH PARAMETERS
ARE THERE NO DOUBT. MAIN STICKING POINT FOR THE FORECAST ARE
LOW-LEVEL WIND FIELDS AND MORE SPECIFICALLY THE WIND DIRECTION WHICH
IS ALL SO CRITICAL FOR PEGGING WHERE HEAVIEST LK EFFECT WILL OCCUR.
UNFORTUNATELY...NOTEABLE DIFFERENCES EXIST BTWN THE NAM/NCEP HIGH
RES RUNS AND THE COARSER ECMWF/GFS AND ALSO THE GEM. MAIN ISSUE IS
HOW QUICKLY SOUTH TO BRING LOW-LEVEL WIND SHIFT PASSAGE ON TUESDAY.
PASSAGE OF THE TROUGH ESSENTIALLY KICKS LK EFFECT FM WNW/NW FLOW
AREAS TO AREAS FAVORED BY N/NNE WINDS. USUALLY LIKE THE NAM WITH
HIGHER RESOLUTION DETAILS...BUT SUCH A QUICK TROUGH PASSAGE AT
15Z-18Z ON TUESDAY IN THE NORTH SEEMS QUESTIONABLE AS SHORTWAVE
TROUGH AXIS IS STILL OVER CNTRL UPR MICHIGAN AT 18Z. WOULD EXPECT
THE TROUGH PASSAGE TO OCCUR TUESDAY EVENING IN THE WAKE OF THE
SHORTWAVE TROUGH CROSSING THE AREA. OVERALL...PREFERRED SOLUTION
IS PROBABLY MOST CLOSEST TO GFS/LOCAL REGIONAL WRF AND ECMWF.
WHAT THIS MEANS IN TERMS OF LK EFFECT SNOW IS EXPECT A PROLONGED
PERIOD OF LK EFFECT FOR WNW/NW FLOW AREAS LATE TONIGHT THROUGH LATE
TUESDAY AFTN /WHITE PINE TO ROCKLAND/TWIN LAKES AND MAYBE AS FAR
NORTH AS HOUGHTON/ AND ALSO OVER NORTHERN PARTS OF ALGER AND LUCE
COUNTIES. HEAVIER LK EFFECT THEN SHIFTS TO GOGEBIC/WESTERN ONTONAGON
AND MARQUETTE COUNTIES BY TUESDAY EVENING. BASED ON EXPECTED SLR/S
NEARING 20:1 OR EVEN ABOVE 20:1 AND QPF WHICH WAS BLEND OF REGIONAL
WRF AND EVENTUALLY THE WETTER NAM DNG LATER TUESDAY...SEEMS LIKE A
SOLID ADVY EVENT IS IN STORE WITH SNOW AMOUNTS OF 4-6/5-8 INCHES IN
THE 12 HOUR PERIOD FOR TUESDAY AND AGAIN ON TUESDAY NIGHT...THOUGH
THE LOCATIONS OF HEAVIEST SNOW SHOULD SHIFT AROUND AS WINDS IN THE
LAKE CONVECTIVE LAYER SO SOME SHEAR AND DO NOT STAY LOCKED IN THE
SAME DIRECTION FOR VERY LONG PERIOD OF TIME. SOME LOCATIONS IN THE
FAR WESTERN CWA /VCNTY OF IWD TO BERGLAND AND WHITE PINE/ MAY COME
CLOSER TO WARNING CRITERIA TUESDAY AFTN INTO TUESDAY NIGHT BUT SINCE
THE LARGER SCALE FORCING IS DIMINISHING WHEN WIND DIRECTION BECOMES
A MORE FAVORABLE N-NNE TO INCREASE CONVERGENCE IN THESE AREAS...WILL
OPT TO ISSUE THE ADVY AND LET FUTURE SHIFTS UPGRADE TO WARNING IF IT
IS NEEDED. SNOW WILL BE THE MAIN ISSUE WITH THIS EVENT. WINDS WILL
BE GUSTY 25-35 MPH...BUT STRONGEST WINDS AND BLSN/VSBY IMPACTS WILL
BE MORE OVER THE NORTHERN PARTS OF THE KEWEENAW ON TUESDAY AND
PERHAPS INTO NCNTRL UPR MICHIGAN ON TUESDAY NIGHT. NOT EXPECTING
WIDESPREAD BLSN AS THE EVENT THIS LAST WEEKEND HAD.
FOR NOW...COORDINATED WITH SHORT TERM FORECASTER AND PUT OUT LAKE
EFFECT SNOW ADVISORIES FOR WESTERN TIER. ADDITIONAL HEADLINES WILL
LIKELY BE ISSUED OVER NCNTRL AND POSSIBLY NORTHEAST CWA LATER TODAY
OR TONIGHT...BUT SINCE THE MORE SIGNIFICANT SNOW WILL NOT OCCUR IN
THESE AREAS UNTIL LATER TUESDAY OR EVEN AS LATE AS TUESDAY NIGHT IF
GFS IS COMPLETELY CORRECT...WILL NOT ISSUE THOSE HEADLINES NOW. NOT
ENOUGH CONFIDENCE THAT THESE AREAS WOULD SEE WARNING AMOUNTS SO DID
NOT WANT TO PUT A WATCH OUT EITHER.
SNOW SHOWERS PERSIST FOR N FLOW AREAS ON WEDNESDAY...BUT INTENSITY
WILL BE ON THE WANE WITH LOWERING INVERSION HEIGHTS TO AT OR BLO
5KFT. EVEN AS SNOW DIMINISHES...THE DGZ WILL BE IN THE HEART OF THE
LAKE CONVECTIVE LAYER SO WHAT SNOW SHOWERS ARE LEFTOVER ON WEDNESDAY
WILL BE THE EFFECIENT FLUFFY TYPE. WINDS WILL BE ON THE DECREASE AS
WELL...AS WILL BLSN/ASSOCIATED VSBY ISSUES. SINCE THE FLOW REMAINS
LGT NORTH ALL DAY AND INSTABILITY IS MORE THAN SUFFICIENT...SNOW
SHOWERS PROBABLY WILL NOT END COMPLETELY FOR FAR WEST OR NCNTRL BUT
THEY MAY BECOME PINNED CLOSER TO THE SHORELINES ON WEDNESDAY NIGHT
AS MESOSCALE EFFECTS/LAND BREEZES START TO DRIVE THE LOW-LEVEL
CONVERGENCE.
STILL COULD SEE SOME LGT SNOW ON THANKSGIVING. NO BIG IMPACT TO
TRAVEL EXPECTED THOUGH. BEST CHANCE OVER THE NORTHERN TIER. WEAK
TROUGH WORKS THROUGH THURSDAY NIGHT INTO FRIDAY. COULD SEE SOME SNOW
SHOWERS ACROSS KEWEENAW IN WNW FLOW ON FRIDAY. WEEKEND WILL FEATURE
MODEST WARMING TREND WITH SOME AREAS SLIGHTLY ABOVE FREEZING FOR
DAYTIME HIGHS. LGT SNOW MAY ACCOMPANY THIS WARM AIR ADVECTION BUT
LOOKS LIKE BETTER CHANCE FOR ANY SNOW ACCUMULATION WILL REMAIN TO
NORTH OF CWA.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1200 PM EST MON NOV 25 2013
AS A STRONG DISTURBANCE OVER ONTARIO AND ITS ATTENDANT SFC COLD
FRONT DIGS SE INTO THE AREA...EXPECT MVFR CIGS AT IWD AND CMX
THROUGH THIS PERIOD WITH LAKE EFFECT SNOW SHOWERS CONTINUING. AS
WINDS GET MORE NORTHERLY WITH TIME...BOTH SITES WILL GO TO IFR VIS
IN THE HEAVIER SNOW SHOWERS STARTING FIRST AT CMX BY THIS EVENING
AND BY TUE MORNING AT IWD. AT SAW...MVFR CIGS WILL MOVE OUT THIS
AFTERNOON WITH A DOWNSLOPE WIND HELPING TO RAISE CIGS TO LOW VFR.
WITH A WEST WIND AT SAW THIS EVENING THROUGH TUE MORNING...MVFR
CONDITIONS WILL SET UP WITH SOME SNOW SHOWERS MOVING IN THIS
EVENING.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 533 AM EST MON NOV 25 2013
SW TO W GALES OVER LAKE SUPERIOR THIS MORNING ARE EXPECTED TO
DIMINISH BY LATE MORNING OVER THE WEST AND MID AFTERNOON OVER THE
EAST. THE PRES GRADIENT WILL WEAKEN AS A TROUGH MOVES THROUGH THE
LAKE AND LOW PRESSURE NORTH OF LAKE SUPERIOR MOVES TOWARD JAMES BAY.
NORTHWEST WINDS TO 25 KTS SHIFT TO THE NORTH TO 30 KTS LATER TUESDAY
AND TUESDAY NIGHT. MAY GET CLOSE TO GALES THOUGH TUESDAY NIGHT INTO
WEDNESDAY MORNING. WINDS DIMINISH TO LESS THAN 25 KTS THURSDAY INTO
FRIDAY AS PRESSURE GRADIENT RELAXES. NEXT PERIOD OF STRONGER WINDS
WILL BE SATURDAY AS SOUTH WINDS INCREASE TO 30 KTS OVER THE EASTERN
LAKE AHEAD OF STRONGER LOW PRESSURE SYSTEM.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY FROM 10 PM EST /9 PM CST/ THIS EVENING
TO NOON EST /11 AM CST/ WEDNESDAY FOR MIZ002-009.
LAKE EFFECT SNOW ADVISORY FROM 10 PM THIS EVENING TO 7 AM EST
WEDNESDAY FOR MIZ001-003.
LAKE SUPERIOR...
GALE WARNING UNTIL 2 PM EST THIS AFTERNOON FOR LSZ266-267.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...JLA
AVIATION...07
MARINE...JLB
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1145 AM CST MON NOV 25 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 327 AM CST MON NOV 25 2013
A WEAK COLD FRONT CURRENTLY MOVING THROUGH SRN SOUTH DAKOTA
SHOULD CLEAR THE FORECAST AREA BY 21Z. A STRONG THERMAL RIDGE IS
RUNNING OUT AHEAD OF THE COLD FRONT WITH SFC TEMPS RISING INTO THE
UPPER 30S. THIS SHOULD MIX OUT THE ATMOSPHERE AND GIVE A HEAD
START TO MAX TEMPS IN THE 40S. THIS IS CLOSE TO THE RAP MODEL
WHICH WAS THE WARMEST SOLN NEXT TO THE ECM GUIDANCE FORECASTING
HIGHS IN THE MID AND UPPER 40S. SOME MID LEVEL CLOUDINESS
ASSOCIATED WITH THE COLD FRONT WOULD SUGGEST USING A FCST SLIGHTLY
COOLER THAN THE VERY WARM ECM GUIDANCE.
FOR TONIGHT...A REINFORCING ARCTIC FRONT...CURRENTLY ACROSS NRN
SASKATCHEWAN WILL BE MOVING THROUGH SD WITH A WEAK THERMAL RIDGE
RUNNING OUT AHEAD OF THIS FRONT. THE MODEL CONSENSUS SUGGESTED LOWS
IN THE TEENS WHICH MIGHT BE TOO COLD. THE MODELS APPEAR TO BE
PUSHING THIS FRONT INTO THE FCST AREA AROUND 06Z TONIGHT WITH H850
MB WINDS INCREASING TO 35 TO 40 KT WHICH WOULD SUPPORT MIXING
AND WARMER LOWS.
NO STRATUS IS EXPECTED WITH EITHER FRONT TODAY OR TONIGHT.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 327 AM CST MON NOV 25 2013
THE SOUTHERN PLAINS UPPER LEVEL LOW WILL PHASE TUESDAY WITH A
STRONG SHORTWAVE DROPPING SOUTHEAST THROUGH CANADA INTO THE GREAT
LAKES REGION. THIS WILL BRING HEAVY PRECIPITATION TO THE EAST
COAST WEDNESDAY. ACROSS OUR AREA...ANOTHER SHOT OF ARCTIC AIR
WILL PLUMMET SOUTH TUESDAY ON THE BACK SIDE OF THE DEVELOPING
EASTERN CONUS STORM. THIS WILL KEEP HIGHS IN THE 20S ONCE AGAIN
ACROSS PORTIONS OF NORTHERN NEBRASKA...WITH LOWER TO MID 30S
ACROSS THE PANHANDLE INTO SOUTHWEST NEBRASKA. THIS COLD AIR WILL
BE SHORT LIVED...AS UPPER LEVEL RIDGING AND A PACIFIC AIRMASS
SPREAD EAST THROUGH THE PLAINS STARTING WEDNESDAY. THE ECMWF HAS
BEEN ADVERTISING A CHINOOK EVENT WEDNESDAY...AND THIS SHOULD HELP
SCOUR OUT THE ARCTIC AIR. SHOULD SEE HIGHS INTO THE 40S ACROSS
WESTERN NEBRASKA...WITH LOWER 30S FARTHER EAST WHERE THE ARCTIC
AIR WILL BE MORE DENSE AND TAKE LONGER TO MIX OUT.
THE UPPER RIDGE BECOMES DOMINATE THANKSGIVING AND FRIDAY...WITH
DRY AND MILD CONDITIONS AREA WIDE. BY THE WEEKEND...THE UPPER
RIDGE WILL BEGIN TO FLATTEN...BUT IT REMAINS MILD AND DRY. MORE
COLD ARCTIC AIR IS POSSIBLE BEYOND THE FORECAST PERIOD AS WE HEAD
INTO NEXT WEEK...AS LARGE GULF OF ALASKA UPPER LEVEL LOW COULD
DROP SOUTHEAST INTO THE PACIFIC NORTHWEST. STAY TUNED.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1144 AM CST MON NOV 25 2013
VFR CONDITIONS ARE EXPECTED TO PREVAIL FOR THE NEXT 24 HOURS
ACROSS WESTERN AND NORTH CENTRAL NEBRASKA. WINDS REMAIN OUT OF THE
NORTHWEST THROUGH 18Z TUESDAY. SCT TO BKN CLOUD DECK WILL HAVE
CIGS WELL ABOVE IFR LEVELS.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CDC
LONG TERM...TAYLOR
AVIATION...MARTIN
AREA FORECAST DISCUSSION
NWS BISMARCK ND
321 PM CST MON NOV 25 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 320 PM CST MON NOV 25 2013
A STRONGER SURGE OF COLD AIR ADVECTION WILL PUSH SOUTH INTO NORTH
DAKOTA OVERNIGHT. AFTERNOON OBS AND REFLECTIVITY NEAR ROLLA...AND
LIGHT QPF SCATTERED ALONG THE EASTERN FRINGES OF THE FORECAST AREA
IN SOME SHORT RANGE MODELS...HAVE PROMPTED INCLUSION OF FLURRIES
FROM THE TURTLE MOUNTAINS THROUGH THE JAMES RIVER VALLEY TONIGHT.
A FEW AFTERNOON OBS AT MINOT AND TIOGA...SUGGESTIVE OF FREEZING
DRIZZLE/UNKNOWN PRECIP...ARE ACTUALLY THE RESULT OF EXISTING SNOW
BEING BLOWN NEAR THE WEATHER SENSOR.
HAVE INCREASED OVERNIGHT CLOUD COVER BASED ON AFTERNOON TRENDS AND
ROBUST LOW LEVEL RH EVIDENT ON THE RAP MODEL. LOWS SHOULD BE IN THE
SINGLE DIGITS TO AROUND 10 DEGREES SOUTH. TUESDAY WILL BE THE
COLDEST DAY OF THE COMING WEEK...WITH HIGHS IN THE TEENS TO LOWER
20S SOUTHWEST.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 320 PM CST MON NOV 25 2013
LATEST EXTENDED SUITE CONTINUES TO SHOW AN ACTIVE PERIOD IN TERMS
OF SUCCESSIVE DRY FRONTAL SYSTEMS SLIDING THROUGH. THE NEXT
POTENTIALLY SIGNIFICANT SYSTEM MAY OCCUR MONDAY AND BEYOND.
A PROGRESSIVE PATTERN BEGINS THE LONG TERM WITH A WAVERING
BAROCLINIC ZONE SHIFTING FROM WEST TO EAST TUESDAY NIGHT AS WARM AIR
ADVECTION COMMENCES. A WEAK COLD FRONT FOLLOWS FOR WEDNESDAY/
WEDNESDAY NIGHT WITH A RETURN TO COLD AIR ADVECTION INTO EARLY
THURSDAY. NEUTRAL ADVECTION TO WEAK WARM AIR ADVECTION RESUMES
FRIDAY INTO SATURDAY. THE ONLY SUFFICIENT LIFT FOR MEASURABLE
PRECIPITATION DURING THIS TIME WOULD BE CONFINED TO THE TURTLE
MOUNTAINS WEDNESDAY AND FRIDAY NIGHT. HAVE COLLABORATED WITH OUR
EASTERN OFFICE AND INCORPORATED A SLIGHT CHC OF SNOW IN THE FAR
NORTHEAST. ANY SNOW ACCUMULATION WOULD BE MINIMAL AT BEST.
THE NEXT SYSTEM TO AFFECT WESTERN AND CENTRAL NORTH DAKOTA SHOWS
SIGNS OF LIGHT PRECIPITATION BREAKING OUT VIA WARM AIR ADVECTION
PROCESSES SUNDAY AFTERNOON INTO SUNDAY NIGHT. HOWEVER IT APPEARS
THE BULK OF PRECIPITATION WOULD BE IN THE FORM OF SNOW MONDAY INTO
MONDAY NIGHT. A DRY SLOT MAY FOLLOW FOR TUESDAY. STILL A LOT OF
UNCERTAINTY THIS FAR OUT AND WILL CONTINUE TO MONITOR FUTURE
MODELS RUNS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 320 PM CST MON NOV 25 2013
EXPECT CONTINUED MAINLY MVFR CEILINGS AT KISN/KMOT/KBIS/KJMS. A
NW WIND WILL GUST BETWEEN 20 AND 30 KTS THROUGH THE AFTERNOON...WITH
THE GUSTINESS DIMINISHING THIS EVENING.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM/AVIATION...RP KINNEY
LONG TERM...KS
AREA FORECAST DISCUSSION
NWS ABERDEEN SD
325 PM CST MON NOV 25 2013
.SHORT TERM...TONIGHT THROUGH WEDNESDAY NIGHT
LEADING EDGE OF THE STRATUS/STRATOCUMULUS DECK IS FIRMLY IN PLACE
ACROSS THE EASTERN CWA...WITH A MASSIVE EXPANSION BACK TO THE
NORTH INTO CANADA. MAIN FORECAST ISSUES OVERNIGHT WILL BE CLOUD
COVER AND THE ONSET OF STRONGER COLD AIR ADVECTION. RUC13 900-850
MB RH HAS A VERY GOOD HANDLE ON CURRENT STRATUS OVER THE REGION SO
USED THAT AS A FORECAST FOR THE OVERNIGHT PERIOD. IT BASICALLY
SHOWS THE STRATUS SLOWLY OOZING SOUTHWEST ACROSS SOUTH DAKOTA
THROUGH 12Z TUESDAY. HAVE INCREASED SKY COVER FROM PREVIOUS
FORECAST AND MAY NEED TO BE BEEFED UP MORE FOR EVENING UPDATES.
WITH ADDITIONAL WEAK SHORTWAVE ENERGY MOVING SOUTH OVER THE AREA
LATE TONIGHT AND THE STRONGER COLD AIR ADVECTION...SEE NO REASON
WHY CLOUDS WOULD BREAK UP OR CEASE TO MOVE ANY FURTHER
SOUTH/SOUTHWEST INTO TUESDAY MORNING. LEFT IN THE MENTION OF
FLURRIES FOR THE EASTERN CWA LATE TONIGHT THROUGH TUESDAY MORNING
IN ASSOCIATION WITH THE WEAK SHORTWAVE ENERGY. CURRENT OBS ACROSS
NORTHEAST ND AND SOUTHERN CANADA SHOW -SN WITH VSBYS GENERALLY
ABOVE 6SM IN ASSOCIATION WITH THE WEAK WAVE. WITH THE ONSET OF
COLDER AIR ALOFT ON TUESDAY...WILL SEE HIGH TEMPS SEVERAL DEGREES
COLDER THAN MONDAY. READINGS WILL BE IN THE TEENS TO MID 20S
ACROSS THE CWA. SURFACE HIGH THEN MOVES THROUGH THE AREA TUESDAY
NIGHT WHICH SHOULD CLEAR THE SKIES AND PROVIDE FOR A PERIOD OF
LIGHT WINDS. ALTHOUGH THE RIDGE AXIS IS PRETTY NARROW AND A QUICK
MOVER...SO BY 12Z WEDNESDAY MUCH OF THE CWA IS ALREADY UNDER
SOUTHERLY SFC WIND FLOW. NOT AN IDEAL RADIATIONAL COOLING
SETUP...BUT WILL STILL GET PRETTY COLD NONETHELESS. WILL BE AROUND
0 DEGREES ACROSS THE EASTERN CWA WITH FAVORED COLD SPOTS PERHAPS
SNEAKING BELOW ZERO. HIGHS ON WEDNESDAY WILL REBOUND SOMEWHAT AS
925MB TEMPS BEGIN TO WARM ON THE BACKSIDE OF THE RETREATING SFC
HIGH. BREEZY WINDS WILL DEVELOP SO THERE WILL BE DECENT MIXING.
HIGHS WILL REMAIN BELOW NORMAL THOUGH AS THE OVERALL PATTERN
REMAINS COLD.
.LONG TERM...THURSDAY THROUGH SUNDAY
NORTHWEST FLOW ALOFT WILL BE THE PREDOMINATE UPPER PATTERN
THROUGH MOST OF THE LONG TERM PERIOD...BUT A PATTERN CHANGE
DOES SEEM TO BE ON THE HORIZON. A SHORTWAVE TROUGH DROPPING OUT
OF CANADA WILL INFLUENCE THE REGION FOR THE FRIDAY/SATURDAY TIME
FRAME...HOWEVER MOST OF THE FORCING APPEARS TO REMAIN NORTH OF OUR
CWA...AND MODEL MOISTURE PROFILES REMAIN FAIRLY DRY AT THIS POINT.
DECENT WARM AIR ADVECTION AHEAD OF THAT WAVE COULD CAUSE SOME
PTYPE ISSUES IF PRECIPITATION WERE TO MATERIALIZE OVER OUR CWA
SATURDAY. ALTHOUGH MODELS VARY ON THE STRENGTH OF THE WARM
PUSH...850 MB TEMPERATURES DO RISE ABOVE 0 C...WITH THE GFS
ADVERTISING AS HIGH AS 6 OR 7 C ACROSS OUR SOUTHERN CWA.
EITHER WAY...CONTINUED WITH THE DRY ALLBLEND FORECAST FOR NOW. BY
SUNDAY WEAK RIDING APPEARS TO BE OVER THE NORTHERN PLAINS...BUT
IT ONLY PRECEDES A MORE SIGNIFICANT UPPER LOW MOVING INTO THE
PACIFIC NORTHWEST.
&&
.AVIATION...
18Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
A STRATUS DECK CONTINUES TO MOVE SOUTHEAST OUT OF NORTH DAKOTA AND
ACROSS NORTHEAST SOUTH DAKOTA. CIGS ARE CURRENTLY IN THE VFR
CATEGORY AT KABR AND KATY...ALTHOUGH MVFR CIGS ARE FORECAST FOR
KATY OVERNIGHT. FLURRIES ARE ALSO POSSIBLE AT KABR AND KATY
OVERNIGHT...HOWEVER DUE TO LOW AREAL COVERAGE AND LITTLE OR NO
VSBY RESTRICTIONS...DID NOT ADD LIGHT SNOW INTO THE TAF FORECAST
FOR NOW. GUSTY NORTHWEST WINDS THIS AFTERNOON WILL DECREASE TO THE
10 TO 15 KT RANGE OVERNIGHT.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
SHORT TERM...TMT
LONG TERM...SERR
AVIATION...SERR
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1110 AM CST MON NOV 25 2013
UPDATED AVIATION PORTION FOR 18Z TAF ISSUANCE
.SHORT TERM...TODAY...TONIGHT...AND TUESDAY
ISSUED AT 406 AM CST MON NOV 25 2013
PRIMARY FOCUS OF SHORT-TERM FORECAST WILL BE LIGHT PRECIPITATION
ASSOCIATED WITH A COUPLE RATHER POTENT NORTHERN STREAM SHORTWAVE
DISTURBANCES DIVING SOUTHEAST ACROSS THE WESTERN GREAT LAKES...AND
INCREASING LES POTENTIAL ACROSS THE LAKE SUPERIOR SNOWBELT.
WATER VAPOR IMAGERY SHOWS FIRST SHORTWAVE DISTURBANCE HEADING
SOUTHEAST TOWARD LAKE SUPERIOR EARLY THIS MORNING. PRIMARY
SYNOPTIC FORCING WITH THIS FEATURE TO REMAIN NORTH OF THE FORECAST
AREA TODAY. FORCING RATHER LACKLUSTER FURTHER SOUTH ASSOCIATED
WITH WEAK SURFACE TROUGH HEADING SOUTHEAST ACROSS MINNESOTA. 00Z
SOUNDINGS AT MPX...GRB AND ILX ONCE AGAIN SUGGEST RATHER PALTRY
DEEP LAYER MOISTURE TO WORK WITH AHEAD OF THIS SYSTEM. THUS AS
INDICATED IN LATEST RADAR DATA...HAVE ONLY BEEN ABLE TO GENERATE
BAND OF VERY WEAK RADAR RETURNS EXTENDING FROM NORTH CENTRAL
WISCONSIN TO SOUTHWEST MINNESOTA. LITTLE OR NO PRECIPITATION
ASSOCIATED WITH THIS FEATURE THUS FAR WITH JUST FLURRIES BEING
REPORTED.
MEANWHILE FURTHER SOUTH...WHERE ANOTHER VERY WEAK IMPULSE...WEAK
FRONTOGENETIC FORCING AND SLIGHTLY DEEPER MOISTURE EXIST...SCATTERED
TO BROKEN SNOW SHOWER ACTIVITY HAS BROKEN OUT OVER EASTERN IOWA.
SHORT RANGE MODEL GUIDANCE SUGGEST THAT THIS ACTIVITY WILL MOVE
ENE AND AFFECT MAINLY THE SOUTHERN THIRD OF THE FORECAST AREA THIS
MORNING. BASED ON LATEST OBSERVATIONS APPEARS MOISTURE IS DEEP
ENOUGH TO GENERATE ICE CRYSTALS RESULTING IN MAINLY SNOW RATHER
THAN FREEZING DRIZZLE. GIVEN THE POORLY ORGANIZED AND WEAK
FORCING...AND UNCERTAINTY IN AVAILABLE MOISTURE OVER THE FORECAST
AREA THIS MORNING...OPTED TO KEEP A MIX OF VERY LIGHT SNOW AND/OR
FREEZING DRIZZLE GOING FOR THE ENTIRE FORECAST AREA THROUGH ABOUT
17Z. GIVEN LATEST RADAR TRENDS AND HRRR FORECAST...APPEARS BEST
CHANCE FOR LIGHT MEASURABLE PRECIPITATION WILL BE OVER THE FOX
VALLEY THIS MORNING...THUS KEPT HIGHEST POPS THERE. WILL CONTINUE TO
MONITOR RADAR TRENDS AND SURFACE OBSERVATIONS ACROSS THIS AREA AS
THERE STILL IS POTENTIAL FOR SUFFICIENT LIGHT SNOW OR LIGHT FREEZING
DRIZZLE TO CREATE A FEW SLICK SPOTS DURING THE MORNING COMMUTE. IF
THIS DOES OCCUR...WILL HANDLE WITH SPS.
GUIDANCE ALSO SUGGESTS THAT SURFACE PRESSURE GRADIENT WILL BE
STRONGEST BETWEEN NOW AND ABOUT 15Z...AND WILL BEGIN TO RELAX
THEREAFTER AS SURFACE TROUGH SWINGS THROUGH THE AREA AROUND
MIDDAY. THUS EXPECT RATHER STRONG SOUTHWEST WINDS TO CONTINUE TO
GUST INTO THE 30-35 MPG RANGE THROUGH MID-MORNING AND DIMINISH
SOMEWHAT THEREAFTER.
NEXT AND SOMEWHAT MORE POTENT SHORTWAVE THEN IMPINGES ON THE
FORECAST AREA TOWARD DAYBREAK TUESDAY. FEEL LARGE-SCALE FORCING
WILL BE A BIT MORE ROBUST SUCH THAT MAY SEE MORE WIDESPREAD SNOW
SHOWER ACTIVITY ESPECIALLY ACROSS NORTH-CENTRAL WISCONSIN TUESDAY.
MORE IMPORTANTLY...AS THIS SYSTEM MOVES ACROSS NORTHERN WISCONSIN
TUESDAY MORNING...BOUNDARY LAYER WINDS WILL VEER TO FAVORABLE 340
DEGREE DIRECTION OVER WESTERN LAKE SUPERIOR TO INITIATE LES BANDS
ONCE AGAIN. GIVEN RATHER IMPRESSIVE SHORTWAVE PASSING THROUGH THIS
AREA...FAVORABLE FETCH AND OVER WATER INSTABILITY...ACCUMULATING
SNOWS SEEM LIKELY ACROSS NORTHWEST VILAS COUNTY STARTING AROUND
18Z TUESDAY AND CONTINUING INTO TUESDAY NIGHT. HOWEVER MODELS DO
SUGGEST BOUNDARY LAYER WINDS WILL VEER TO A LESS FAVORABLE 360
DEGREES BY 06Z WEDNESDAY. WILL LET DAY-SHIFT TAKE A CLOSER LOOK AT
THE LES POTENTIAL FOR LATER TUESDAY INTO TUESDAY NIGHT...BUT WOULD
NOT BE SURPRISED TO SEE ADVISORY HOISTED AT SOME POINT.
.LONG TERM...TUESDAY NIGHT THROUGH SUNDAY
ISSUED AT 406 AM CST MON NOV 25 2013
UPPER LEVEL FLOW ACROSS THE NORTHERN CONUS IS FORECAST TO BECOME
LESS AMPLIFIED/MORE ZONAL BY THE END OF THE WEEK. THIS WILL RESULT
IN THE THERMAL TROUGH...THAT SHOULD BE OVER THE AREA TUESDAY
NIGHT...SHIFTING EAST OF WISCONSIN. WARM ADVECTION LATER DURING
THE WEEK WILL BRING NEAR NORMAL HIGH TEMPERATURES BY THE WEEKEND.
LAKE EFFECT SHOULD COME TO AN END IN THE FORECAST AREA BY
WEDNESDAY AFTERNOON AS A SURFACE RIDGE REACHES THE STATE. SNOW
WITH THE NEXT CLIPPER SYSTEM SHOULD REMAIN NORTH OF THE STATE...SO
ONLY SOME SLIGHT CHANCES FOR SNOW IN THE FAR NORTH ON THURSDAY.
THE NEXT SYSTEM AFTER THAT IS EXPECTED TO PUSH FARTHER SOUTH AND
BRING A CHANCE FOR SNOW SHOWERS TO NORTHERN WISCONSIN ON SATURDAY.
LITTLE MOISTURE WILL ACCOMPANY THESE SYSTEMS SO ANY ACCUMULATION
SHOULD BE MINOR.
&&
.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1055 AM CST MON NOV 25 2013
FIRST BAND OF LIGHT SNOW SHIFTED EAST OF THE AREA THIS MORNING WITH
MVFR CIGS LINGERING ACROSS THE AREA. CIGS SHOULD RISE INTO THE VFR
CATEGORY LATER THIS AFTERNOON AND THIS EVENING. ATTENTION THEN TURNS
TO REINFORCING SHOT OF COLD AIR WITH ARCTIC COLD FRONT THAT WILL
SWEEP ACROSS THE AREA LATER TONIGHT INTO TUESDAY MORNING. EXPECT A
BAND OF LIGHT SNOW OR FLURRIES / MVFR CIGS ALONG THE FRONT...AS
NOTED ACROSS THE NORTHERN PLAINS LATE THIS MORNING. HAVE TRIED TO
TIME THE LIGHT SNOW IN THE 18Z TAFS. VISIBILITIES FOR A BRIEF
PERIOD OF TIME MAY BE EVEN LOWER THAN WHAT IS IN THE FORECAST AT
EACH TAF SITE.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....ESB
LONG TERM......MG
AVIATION.......ECKBERG