Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 11/24/12
AREA FORECAST DISCUSSION
NWS JACKSONVILLE FL
652 PM EST FRI NOV 23 2012
.UPDATE...
CLEAR SKIES PREVAIL THIS EVENING ACROSS THE REGION...WITH A DRY COLD
FRONT APPROACHING FROM CENTRAL GA. ABOUT A 100 MILE STRETCH OF MID
DECK CLOUDS ARE ASSOCIATED WITH THE FRONT. THESE CLOUDS WILL ENTER
INTERIOR SECTIONS OF SE GA BY LATE THIS EVENING...MOVING SOUTH INTO
NE FL OVERNIGHT. ALTHOUGH THE FRONT WILL MOVE INTO A DRIER AIRMASS
STILL THINK SOME CLOUDS WILL REMAIN...THUS HAVE INCREASED SKY COVER
ACROSS SE GA INTO NE FL...WITH PARTLY TO MOSTLY CLOUDY SKIES LATER
TONIGHT. THESE CLOUDS WILL LIKELY PUT A CAP ON THE TEMPERATURE FALL
WITH LOWS ONLY FALLING INTO THE MID/UPPER 40S FOR MOST OF NE FL
WITH A LITTLE COOLER READINGS FOR SE GA AS THE CLOUDS WILL EXIT BY
LATER IN THE OVERNIGHT.
&&
.AVIATION...
A DRY COLD FRONT TRAILED BY CEILINGS OF 3-6 KFT WAS PROGRESSING
SOUTHWARD OVER N GA THIS EVENING. THE RAP SHORT TERM GUIDANCE AND
MOS STATISTICS SUGGESTED THAT THIS BAND OF STRATUS WOULD COMPLETELY
EVAPORATE BEFORE REACHING THE ALTAMAHA RIVER BASIN...BUT BASED ON
EVENING SATELLITE TRENDS THERE WAS LITTLE SIGN OF THIS LOW LEVEL
MOISTURE THINNING SIGNIFICANTLY. FOR THE 00Z TAF PACKAGE INTRODUCED
A BROKEN 3KFT AT SSI BETWEEN 04-08Z BASED ON THE DECKS RECENT SPEED
OF ADVANCEMENT SOUTHWARD. ALSO INTRODUCED BROKEN CEILINGS OF 5 KFT
AROUND 07Z AT JAX...CRG AND VQQ. IF THE STRATUS CONTINUES TO SHOW
SIGNS OF HOLDING TOGETHER FOR THE NEXT SEVERAL HOURS AFTER
SUNSET...WILL AMENDED THE NE FL TAFS TO INCLUDED TEMPO MVFR CIGS
EARLY SAT MORNING. VFR CONDITIONS WILL DEVELOP FROM NW TO SE SAT
MORNING AS MUCH DRIER AND COLDER POST-FRONTAL AIR MIXES DOWN WITH
WNW WINDS 10-15 KT AND GUSTS 15-20 KT POSSIBLE.
&&
.MARINE...
SCA SEAS CONTINUE AT BUOY 41012...THUS WILL CONTINUE SCA FOR SEAS
OFFSHORE THROUGH EARLY SUNDAY MORNING...AS EASTERLY SWELLS ARE
EXPECTED TO PERSIST. GENTLE TO MODERATE NORTHWEST WINDS THIS
EVENING WILL BECOME WEST TO NORTHWESTERLY AND INCREASE TO 15 TO
20 KNOTS OVERNIGHT AS A DRY COLD FRONT MOVES THROUGH. HIGH PRESSURE
WILL THEN BUILD INTO OUR REGION SATURDAY THROUGH SUNDAY NIGHT. EXPECT
WINDS TO VEER TO SOUTHERLY BY MONDAY NIGHT AND TUESDAY AS THE NEXT
COLD FRONT APPROACHES.
RIP CURRENTS: HIGH RISK THROUGH TONIGHT AT THE NORTHEAST FL BEACHES
WITH MODERATE RISK FOR SE GA BEACHES. A MODERATE TO HIGH RISK OF
RIP CURRENTS IS ANTICIPATED ON SATURDAY FOR NORTHEAST FLORIDA AS
EASTERLY SWELLS WILL BE SLOW TO SUBSIDE.
&&
.FIRE WEATHER...
NORTHWESTERLY WINDS WILL INCREASE TO 10-15 MPH BY LATE SATURDAY
MORNING IN THE WAKE OF A DRY COLD FRONTAL PASSAGE. WILL CONTINUE
THE FIRE WEATHER WATCH FOR NE FL SATURDAY FOR HIGH DISPERSION
VALUES AND CRITICALLY LOW RH. ALTHOUGH WINDS WILL DECREASE AS
HIGH PRESSURE BUILDS INTO OUR AREA ON SUNDAY...LONG DURATIONS OF
CRITICALLY LOW RELATIVE HUMIDITY VALUES ALONG WITH ERC VALUES
CLIMBING TO NEAR 35 UNITS MAY BRING RED FLAG CONDITIONS TO INTERIOR
LOCATIONS OF NORTHEAST FLORIDA DURING THE AFTERNOON HOURS. RELATIVE
HUMIDITY VALUES SHOULD THEN SLOWLY RECOVER BY MONDAY AFTERNOON AS
HIGH PRESSURE SHIFTS EAST OF THE REGION AHEAD OF AN APPROACHING
COLD FRONT.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG 41 61 29 64 / 0 0 0 0
SSI 50 63 40 64 / 0 0 0 0
JAX 47 65 32 65 / 0 0 0 0
SGJ 50 66 38 62 / 0 0 0 0
GNV 45 66 31 66 / 0 0 0 0
OCF 45 68 32 68 / 0 0 0 0
&&
.JAX WATCHES/WARNINGS/ADVISORIES...
FL...FREEZE WATCH FROM LATE SATURDAY NIGHT THROUGH SUNDAY MORNING FOR
ALACHUA-BAKER-BRADFORD-CLAY-COLUMBIA-DUVAL-GILCHRIST-
HAMILTON-MARION-NASSAU-PUTNAM-SUWANNEE-UNION.
HIGH RIP CURRENT RISK UNTIL 5 AM EST SATURDAY FOR DUVAL-FLAGLER-
NASSAU-ST JOHNS.
FIRE WEATHER WATCH FROM SATURDAY MORNING THROUGH SATURDAY
AFTERNOON FOR ALACHUA-BAKER-BRADFORD-CLAY-COLUMBIA-DUVAL-
FLAGLER-GILCHRIST-HAMILTON-MARION-NASSAU-PUTNAM-ST JOHNS-
SUWANNEE-UNION.
GA...FREEZE WATCH FROM LATE SATURDAY NIGHT THROUGH SUNDAY MORNING FOR
APPLING-ATKINSON-BACON-BRANTLEY-CHARLTON-CLINCH-COFFEE-
ECHOLS-INLAND CAMDEN-INLAND GLYNN-JEFF DAVIS-PIERCE-WARE-
WAYNE.
AM...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 6 AM EST SUNDAY
FOR ALTAMAHA SOUND GA TO FERNANDINA BEACH FL 20 NM TO 60 NM
OFFSHORE-FERNANDINA BEACH TO ST AUGUSTINE FL 20 NM TO 60 NM
OFFSHORE-ST AUGUSTINE TO FLAGLER BEACH FL 20 NM TO 60 NM
OFFSHORE.
&&
$$
ALLEN/ENYEDI/LETRO
AREA FORECAST DISCUSSION
NWS DES MOINES IA
328 AM CST THU NOV 22 2012
.SHORT TERM /TODAY/...
MAIN CONCERN TODAY WILL BE THE WIND FOLLOWING THE FRONT BETWEEN
MID TO LATE AFTERNOON HOURS ACROSS THE NORTH. GUIDANCE AND BUFR
SOUNDINGS STILL SUGGEST SUSTAINED WINDS NEAR 30 MPH IN THE
ADVISORY AREA WITH GUSTS TO NEAR 40 TO 45 MPH BY MID AFTERNOON.
THE PEAK CONDITIONS ARE ONLY EXPECTED TO LAST ABOUT 2 TO 3 HOURS
BETWEEN 2 AND 5 PM AND AS SUN SETS...EXPECT THAT WIND GUSTS WILL
DROP OFF RATHER QUICKLY. ANOTHER WARM DAY IS EXPECTED FOR
THANKSGIVING WITH SOUTH WINDS AHEAD OF THE ADVANCING COLD FRONT.
HIGHS WILL REACH THE 60S OVER MUCH OF THE SOUTHEAST WHILE THE
NORTHWEST WILL BEGIN TO SEE HIGHS RETREATING INTO THE 50S FOR THE
DAY. BY 12Z FRONT WILL REACH FAR NW CORNER WITH FRONT NEARLY
BISECTING THE REGION BY 18Z. FRONT WILL BE THROUGH THE REGION BY
LATE AFTERNOON WITH FALLING TEMPERATURES BEHIND THE SYSTEM.
MOISTURE IS STILL LACKING WITH THE SYSTEM AND WILL CONTINUE ONLY
SLIGHT CHANCES FOR RAIN IN THE FAR SOUTHEAST FOR EARLY AFTERNOON
HOURS. REMAINDER OF THE AREA WILL BE RAIN FREE.
.LONG TERM /TONIGHT THROUGH WEDNESDAY/...
MAIN FORECAST CONCERN FOR BEGINNING OF EXTENDED WILL BE WINDS
TONIGHT AND TEMPERATURES. FRONT WILL CONTINUE TO PUSH ACROSS THE
FAR SE OF CWA OVERNIGHT TONIGHT...WITH MUCH COLDER TEMPERATURES
AND STRONG WINDS BEHIND THE FRONT. HAVE KEPT WINDS UP OVERNIGHT
WITH STRONG PUSH OF SUBSIDENCE BEHIND FRONT AND CAA. WITH STRONG
WINDS WILL KEEP WIND ADVISORY THROUGH THE OVERNIGHT HOURS ACROSS
THE NORTH. AS LOW PULLS EASTWARD...WINDS WILL RELAX A BIT FOR
FRIDAY AFTERNOON...BUT COLD CANADIAN AIR WILL CONTINUE TO STREAM
OVER REGION...WITH HIGHS SLIGHTLY BELOW NORMAL. BROAD UPPER LEVEL
RIDGE WILL REMAIN OVER PLAINS FOR THE WEEKEND...WITH SURFACE HIGH
PRESSURE PUSHING SE. HAVE DROPPED TEMPERATURES A FEW DEGREES
FRIDAY NIGHT AS CONDITIONS LOOK RIGHT FOR A GOOD RADIATIONAL
COOLING NIGHT WITH LIGHT WINDS AND CLEAR SKIES AND CENTER OF HIGH
PASSING WEST OF CWA. WAA WILL THEN SET IN FOR SATURDAY AND SUNDAY
AND SOUTHERLY FLOW WILL RETURN WITH TEMPERATURES WARMING SLIGHTLY
FOR THE END OF THE WEEKEND AHEAD OF ANOTHER FRONTAL BOUNDARY.
ANOTHER WEEK FRONTAL BOUNDARY WILL PUSH SOUTH ACROSS IOWA FOR LATE
SUNDAY...WITH LIMITED MOISTURE...HAVE OPTED TO KEEP CONDITIONS DRY
FOR SUNDAY AND SUNDAY NIGHT...THOUGH CANNOT RULE OUT LIGHT
RAIN...DO NOT HAVE ENOUGH CONFIDENCE TO INCLUDE MENTION ATTM.
SYSTEM BECOME MUDDLED WITH LITTLE MODEL AGREEMENT. ECMWF CONTINUES
TO PUSH FRONT SOUTH...WITH GEM AND GFS PULLING AN AREA OF LOW
PRESSURE NE ACROSS THE AREA. HAVE CONTINUED TO TREND TOWARD THE
WETTER GEM/GFS SOLUTION WITH ECMWF/S DRY SOLUTION STILL AN
OUTLIER. SYSTEM WILL QUICKLY PULL EASTWARD WITH PRECIP CHANCES
ENDING BY TUESDAY NIGHT. WITH COOLER TEMPERATURES BEHIND FRONT
COULD SEE RAIN/SNOW MIX CHANGING OVER TO SNOW MONDAY NIGHT INTO
TUESDAY. HOWEVER ACCUMULATIONS LOOK TO BE MINIMAL ATTM. AS UPPER
LEVEL NORTHWEST FLOW RETURNS FOR REMAINDER OF THE PERIOD...ANOTHER
FAST MOVING SYSTEM IS EXPECTED TO PUSH ACROSS IOWA FOR LATE IN THE
PERIOD. HOWEVER...HAVE OPTED TO KEEP CONDITIONS DRY FOR NOW GIVEN
DIFFICULTY IN TIMING SUCH QUICK SYSTEM SO FAR OUT.
&&
.AVIATION...22/06Z
PRIMARY CONCERN REMAINS WINDS THROUGH THE PERIOD. SFC WINDS WILL
REMAIN STEADY FROM THE SOUTH TONIGHT...BUT EXPECT LLWS TO PERSIST AT
KDSM/KALO/KOTM WITH LATEST RAP STILL SHOWING 500M AGL WINDS /1600
FT/ AROUND 50KTS. HAVE REMOVED LLWS AT KFOD/KMCW HOWEVER WHERE
WINDS ARE ALREADY GUSTING INTO THE 20S. LLWS SHOULD END BY MORNING
WITH COLD FRONT REACHING NWRN IA BY 12Z. WINDS WILL THEN BECOME
GUSTY BEHIND MIDDAY AND AFTERNOON COLD FRONTAL PASSAGE...GENERALLY
25-30KTS BUT A FEW PERIODS OF HIGHER GUSTS ARE ALSO POSSIBLE. GUSTY
WINDS WILL CONTINUE BEYOND THE VALID PERIOD AND MAY EVEN BE STRONGER
THU NIGHT INTO EARLY FRI.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM NOON TODAY TO 6 AM CST FRIDAY FOR CALHOUN-
CERRO GORDO-EMMET-HANCOCK-HUMBOLDT-KOSSUTH-PALO ALTO-POCAHONTAS-
SAC-WEBSTER-WINNEBAGO-WORTH-WRIGHT.
&&
$$
SHORT TERM...REV
LONG TERM...AWB
AVIATION...SMALL
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1127 PM CST WED NOV 21 2012
.SHORT TERM /TONIGHT/...
FAIRLY TIGHT PRESSURE GRADIENT WILL CONTINUE
TO PROVIDE GUSTY SOUTH WINDS THROUGH THE OVERNIGHT HOURS AS A
SURFACE LOW AND COLD FRONT APPROACH THE STATE. THE SURFACE LOW LOOKS
TO BE CENTERED OVER NORTHERN MN BY AROUND 12Z AND COLD FRONT WILL BE
CLOSE TO WESTERN IOWA. WENT AT OR SLIGHTLY ABOVE GUIDANCE FOR
OVERNIGHT LOWS TONIGHT...NAM BEING THE COLDEST COMPARED TO THE
ECMWF/GFS.
.LONG TERM /THURSDAY THROUGH WEDNESDAY/...
THURSDAY WILL BEGIN QUITE MILD WHICH WILL CONTINUE THROUGH NOON. A
SHORT WAVE LIFTING THROUGH THE WEAKENING SOUTHWEST FLOW COULD BRING
A FEW CLOUDS AND LIGHTS SHOWERS TO THE SOUTHEAST WHICH COULD TEMPER
TEMPERATURES A BIT. A COLD FRONT WILL ENTER THE NORTHWEST AREA BY
LATE MORNING THEN MOVE ACROSS THE REMAINDER OF CENTRAL IOWA THE
REMAINDER OF THE DAY. TEMPERATURES WILL BE STEADY OR SLIGHTLY RISING
WITH THE INITIAL FROPA DUE TO INCREASED MIXING BEFORE FALLING. THE
MIXING WILL ALSO INCREASE THE WINDS THROUGH THE AFTERNOON. THE COLD
ADVECTION WILL PROMOTE EFFICIENT MOMENTUM TRANSFER OF MIXED LAYER
WINDS TO THE SURFACE. THIS WILL PUSH WINDS TO WIND ADVISORY CRITERIA
OVER NORTHERN IOWA BY MID THURSDAY AFTERNOON. THE WINDS WILL
DIMINISH A BIT INTO THE EVENING BEFORE ANOTHER SURGE OF COLD
ADVECTION DROPS SOUTH OUT OF MINNESOTA LATE EVENING AND THROUGH THE
REMAINDER OF THE NIGHT. THIS SURGE OF COLD ADVECTION WILL INCREASE
LOW LEVEL MIXING ONCE AGAIN THOUGH MIXED LAYER WINDS WILL BE HIGHER
THAN THE AFTERNOON. SHOULD REACH WIND ADVISORY CRITERIA AGAIN
ESPECIALLY OVER NORTHERN IOWA. HAVE ISSUED A WIND ADVISORY FOR
PORTIONS OF THE NORTH FOR THURSDAY AFTERNOON AND NIGHT TO COVER
THESE EVENTS WHICH WILL IMPACT HOLIDAY TRAVEL.
FRIDAY WILL BE A COLD AND BLUSTERY DAY WITH BREEZY NORTHWEST WINDS
AND TEMPERATURES IN THE 30S. HIGH PRESSURE WILL SETTLE IN FRIDAY
NIGHT WITH TEMPERATURES FALLING INTO THE TEENS MOST AREAS. SOUTHERLY
WINDS WILL DEVELOP ON SATURDAY HOWEVER A STEEP LOW LEVEL INVERSION
AND MID LEVEL THETA-E ADVECTION INDUCED CLOUDS WILL LIMIT MODERATION
POTENTIAL. SUNDAY WILL BE WARMER AND CLOSER TO CLIMATOLOGY. A SHORT
WAVE DROPPING THROUGH THE NORTHWEST FLOW EARLY NEXT WEEK WILL DRIVE
A LONG WAVE TROUGH INTO THE REGION ALONG WITH ANOTHER COLD FRONT
PUSHING TEMPERATURES BACK INTO THE 30S. THE PRIMARY PRECIPITATION
EVENT AND LOW PRESSURE SYSTEM SHOULD TRACK SOUTHEAST OF IOWA AND
INTO THE OHIO VALLEY. LIGHT RAIN OR SNOW IS POSSIBLE BUT LITTLE TO
NO ACCUMULATION OF THE WHITE STUFF IS EXPECTED.
&&
.AVIATION...22/06Z
PRIMARY CONCERN REMAINS WINDS THROUGH THE PERIOD. SFC WINDS WILL
REMAIN STEADY FROM THE SOUTH TONIGHT...BUT EXPECT LLWS TO PERSIST AT
KDSM/KALO/KOTM WITH LATEST RAP STILL SHOWING 500M AGL WINDS /1600
FT/ AROUND 50KTS. HAVE REMOVED LLWS AT KFOD/KMCW HOWEVER WHERE
WINDS ARE ALREADY GUSTING INTO THE 20S. LLWS SHOULD END BY MORNING
WITH COLD FRONT REACHING NWRN IA BY 12Z. WINDS WILL THEN BECOME
GUSTY BEHIND MIDDAY AND AFTERNOON COLD FRONTAL PASSAGE...GENERALLY
25-30KTS BUT A FEW PERIODS OF HIGHER GUSTS ARE ALSO POSSIBLE. GUSTY
WINDS WILL CONTINUE BEYOND THE VALID PERIOD AND MAY EVEN BE STRONGER
THU NIGHT INTO EARLY FRI.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY THURSDAY AFTERNOON THROUGH THURSDAY NIGHT
EMMET-KOSSUTH-WINNEBAGO-WORTH-PALO ALTO-HANCOCK-CERRO GORDO-
POCAHONTAS-HUMBOLDT-WRIGHT-SAC-CALHOUN-WEBSTER
&&
$$
SHORT TERM...PODRAZIK
LONG TERM...DONAVON
AVIATION...SMALL
AREA FORECAST DISCUSSION
NWS GOODLAND KS
950 AM MST THU NOV 22 2012
.SHORT TERM...(TODAY THROUGH SATURDAY NIGHT)
ISSUED AT 226 AM MST THU NOV 22 2012
MAIN FORECAST ISSUE WILL BE THE WINDS TODAY WITH MINOR CONCERNS OF
HOW MUCH IT COOLS OFF THROUGH TOMORROW AND HOW MUCH THE WARM UP IS
ON SATURDAY. SATELLITE SHOWING AN AMPLIFIED PATTERN OVER THE PACIFIC
WITH A LESS AMPLIFIED MORE PROGRESSIVE FLOW FROM NORTH AMERICA INTO
THE ATLANTIC. COLD FRONT IS APPROACHING THE AREA FROM THE NORTHWEST.
AT JET LEVEL...THE ECMWF WAS DOING A LITTLE BETTER THAN THE UKMET...
CANADIAN...AND NAM ON THE JET SEGMENT ASSOCIATED WITH THE NORTHERN
STREAM SYSTEM. THE GFS FOLLOWED BY THE SREF WAS TOO STRONG WITH THE
JET BEHIND THE INCOMING TROUGH. AT MID LEVELS THE MODELS INITIALIZED
FINE WITH NO BIG PROBLEMS. THE RUC AND NAM WERE DOING BEST ON THE
WIND/PRESSURE FIELD. LOW LEVEL THERMAL GUIDANCE WAS CLOSE TO EACH
OTHER AND REALITY.
TODAY/TONIGHT...SATELLITE AND UPPER AIR IS SHOWING A VERY DRY AND
SUBSIDENT AIR MASS BEHIND THE SYSTEM MOVING ALONG THE CANADIAN AND
UNITED STATES BORDER.
SURFACE TO 850 MB WINDS ARE HIGHEST AT 12Z AND THEN DECREASE BY 18Z.
SOME PLACES COULD REACH 35 KNOT GUSTS. HIGHEST OBSERVED 3 HOUR
PRESSURE RISES HAVE OCCURRED MUCH FURTHER NORTH AND ARE NOT ANYTHING
OUT OF THE ORDINARY AT THIS TIME. FORECAST PRESSURE GRADIENT AND 3
HOUR PRESSURE RISES ARE HIGHEST EARLY ON AND DECREASE BY 18Z. IN FACT
BOTH WOULD INDICATE A QUICK BURST OF THE STRONGEST WINDS RIGHT AFTER
THE FROPA AND SUPPORT WINDY CONDITIONS BUT NOT QUITE AT ADVISORY
CRITERIA. STRONGEST SUBSIDENCE LOOKS TO BE NEAR THE NORTHERN PORTION
OF OUR AREA. THAT AND OTHER GUIDANCE WOULD SUPPORT THE HIGHEST WINDS
TO BE IN THE NORTHERN PORTION OF THE AREA AND MAYBE SOME OF THE
SOUTHWEST. SO HAVE CONTINUE TO HAVE WINDS JUST UNDER ADVISORY
CRITERIA WITH THE NORTH THE CLOSEST.
HIGH LEVEL CLOUDS WILL BE THICKEST EARLY DUE TO THE RIGHT REAR
QUADRANT OF THE MID AND UPPER JET BEING CLOSE. OVERNIGHT
TEMPERATURES HAVE BEEN ALL OVER THE PLACE AS THE PREFRONTAL TROUGH
WORKS ITS WAY ACROSS. FRONT LOOKS TO PUSH THROUGH THE AREA EARLY
TODAY. NWP IS WARMER THAN IT WAS YESTERDAY AND IN CLOSE AGREEMENT.
MADE ONLY SLIGHT ADJUSTMENTS.
GUIDANCE THIS MORNING KEEPS THE WINDS STRONGER FOR TONIGHT THAN THE
IT DID YESTERDAY DUE TO THE SURFACE RIDGE MOVING IN A LITTLE
SLOWER. SO WARMED UP THE MINS.
FRIDAY/FRIDAY NIGHT...SHOULD SEE PLENTY OF SUN WITH AREA COMING
UNDER THE CONTROL OF RIDGING/SUBSIDENCE/DRYING. SURFACE HIGH MOVES
ACROSS DURING THE DAY AND IS NOT TOO FAR EAST OF THE AREA BY LATE IN
THE AFTERNOON. NEW GUIDANCE IS CLOSE TO EACH OTHER AND NOT TOO
DIFFERENT FROM ONGOING FORECAST SO MADE LITTLE IF ANY CHANGES. WIND
FIELD STARTS OUT LIGHT BEFORE WAA AND DOWNSLOPE STARTS. TEMPERATURES
COULD FALL RAPIDLY BEFORE THIS GETS GOING.
SATURDAY/SATURDAY NIGHT...AGAIN LOOKS LIKE A LOT OF SUN THROUGH THE
DAY. WINDS STAY LIGHT THROUGH THE DAY BUT MOSTLY FROM A DOWNSLOPE
DIRECTION. NEWER GUIDANCE IS PRETTY CLOSE TO EACH OTHER AND WARMER
THAN CURRENT FORECAST. CONSIDERING THE DEEP/INCREASING WESTERLY FLOW
ALOFT THIS DOES MAKE SENSE. DRY AIR MASS AND DRY GROUND SHOULD ALLOW
A QUICK RESPONSE TO THE EVEN LIGHT DOWNSLOPE WIND. HOWEVER MAY HAVE
SOME WAVE CLOUDS DEVELOP EVEN THOUGH MODELS SAY NO. WILL WARM UP
MAXES SOME AT THIS TIME.
.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 1142 PM MST WED NOV 21 2012
SHORTWAVE TROUGH WILL MOVE FROM THE NORTHERN ROCKIES TO THE
CENTRAL PLAINS SUNDAY NIGHT AND MONDAY. MODEL SOLUTIONS CONTINUE TO
RETREAT FROM PRECIPITATION CHANCES...AND ITS LOOKING LIKE LITTLE
TO NONE IN THE LOCAL AREA. COLDER AIR WILL MOVE IN BEHIND THE COLD
FRONT SUNDAY NIGHT BUT COOL DOWN WILL BE SHORT LIVED. UPPER RIDGE
WILL QUICKLY REBUILD OVER THE GREAT BASIN EARLY IN THE WEEK THEN
ROCKIES BY MID WEEK. TEMPERATURES WILL RETURN TO ABOVE NORMAL BY
TUESDAY WITH NO PRECIPITATION CHANCES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 948 AM MST THU NOV 22 2012
VFR CONDITIONS WILL CONTINUE FOR THE NEXT 24 HOURS AT KGLD AND
KMCK. GUSTY NORTH WIND WILL GRADUALLY DECREASE BY SUNSET AND
OVERNIGHT INTO FRIDAY MORNING AS HIGH PRESSURE BUILDS INTO THE
REGION BEHIND THE COLD FRONT.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...BULLER
LONG TERM...024
AVIATION...032
AREA FORECAST DISCUSSION
NWS GOODLAND KS
418 AM MST THU NOV 22 2012
.SHORT TERM...(TODAY THROUGH SATURDAY NIGHT)
ISSUED AT 226 AM MST THU NOV 22 2012
MAIN FORECAST ISSUE WILL BE THE WINDS TODAY WITH MINOR CONCERNS OF
HOW MUCH IT COOLS OFF THROUGH TOMORROW AND HOW MUCH THE WARM UP IS
ON SATURDAY. SATELLITE SHOWING AN AMPLIFIED PATTERN OVER THE PACIFIC
WITH A LESS AMPLIFIED MORE PROGRESSIVE FLOW FROM NORTH AMERICA INTO
THE ATLANTIC. COLD FRONT IS APPROACHING THE AREA FROM THE NORTHWEST.
AT JET LEVEL...THE ECMWF WAS DOING A LITTLE BETTER THAN THE UKMET...
CANADIAN...AND NAM ON THE JET SEGMENT ASSOCIATED WITH THE NORTHERN
STREAM SYSTEM. THE GFS FOLLOWED BY THE SREF WAS TOO STRONG WITH THE
JET BEHIND THE INCOMING TROUGH. AT MID LEVELS THE MODELS INITIALIZED
FINE WITH NO BIG PROBLEMS. THE RUC AND NAM WERE DOING BEST ON THE
WIND/PRESSURE FIELD. LOW LEVEL THERMAL GUIDANCE WAS CLOSE TO EACH
OTHER AND REALITY.
TODAY/TONIGHT...SATELLITE AND UPPER AIR IS SHOWING A VERY DRY AND
SUBSIDENT AIR MASS BEHIND THE SYSTEM MOVING ALONG THE CANADIAN AND
UNITED STATES BORDER.
SURFACE TO 850 MB WINDS ARE HIGHEST AT 12Z AND THEN DECREASE BY 18Z.
SOME PLACES COULD REACH 35 KNOT GUSTS. HIGHEST OBSERVED 3 HOUR
PRESSURE RISES HAVE OCCURRED MUCH FURTHER NORTH AND ARE NOT ANYTHING
OUT OF THE ORDINARY AT THIS TIME. FORECAST PRESSURE GRADIENT AND 3
HOUR PRESSURE RISES ARE HIGHEST EARLY ON AND DECREASE BY 18Z. IN FACT
BOTH WOULD INDICATE A QUICK BURST OF THE STRONGEST WINDS RIGHT AFTER
THE FROPA AND SUPPORT WINDY CONDITIONS BUT NOT QUITE AT ADVISORY
CRITERIA. STRONGEST SUBSIDENCE LOOKS TO BE NEAR THE NORTHERN PORTION
OF OUR AREA. THAT AND OTHER GUIDANCE WOULD SUPPORT THE HIGHEST WINDS
TO BE IN THE NORTHERN PORTION OF THE AREA AND MAYBE SOME OF THE
SOUTHWEST. SO HAVE CONTINUE TO HAVE WINDS JUST UNDER ADVISORY
CRITERIA WITH THE NORTH THE CLOSEST.
HIGH LEVEL CLOUDS WILL BE THICKEST EARLY DUE TO THE RIGHT REAR
QUADRANT OF THE MID AND UPPER JET BEING CLOSE. OVERNIGHT
TEMPERATURES HAVE BEEN ALL OVER THE PLACE AS THE PREFRONTAL TROUGH
WORKS ITS WAY ACROSS. FRONT LOOKS TO PUSH THROUGH THE AREA EARLY
TODAY. NWP IS WARMER THAN IT WAS YESTERDAY AND IN CLOSE AGREEMENT.
MADE ONLY SLIGHT ADJUSTMENTS.
GUIDANCE THIS MORNING KEEPS THE WINDS STRONGER FOR TONIGHT THAN THE
IT DID YESTERDAY DUE TO THE SURFACE RIDGE MOVING IN A LITTLE
SLOWER. SO WARMED UP THE MINS.
FRIDAY/FRIDAY NIGHT...SHOULD SEE PLENTY OF SUN WITH AREA COMING
UNDER THE CONTROL OF RIDGING/SUBSIDENCE/DRYING. SURFACE HIGH MOVES
ACROSS DURING THE DAY AND IS NOT TOO FAR EAST OF THE AREA BY LATE IN
THE AFTERNOON. NEW GUIDANCE IS CLOSE TO EACH OTHER AND NOT TOO
DIFFERENT FROM ONGOING FORECAST SO MADE LITTLE IF ANY CHANGES. WIND
FIELD STARTS OUT LIGHT BEFORE WAA AND DOWNSLOPE STARTS. TEMPERATURES
COULD FALL RAPIDLY BEFORE THIS GETS GOING.
SATURDAY/SATURDAY NIGHT...AGAIN LOOKS LIKE A LOT OF SUN THROUGH THE
DAY. WINDS STAY LIGHT THROUGH THE DAY BUT MOSTLY FROM A DOWNSLOPE
DIRECTION. NEWER GUIDANCE IS PRETTY CLOSE TO EACH OTHER AND WARMER
THAN CURRENT FORECAST. CONSIDERING THE DEEP/INCREASING WESTERLY FLOW
ALOFT THIS DOES MAKE SENSE. DRY AIR MASS AND DRY GROUND SHOULD ALLOW
A QUICK RESPONSE TO THE EVEN LIGHT DOWNSLOPE WIND. HOWEVER MAY HAVE
SOME WAVE CLOUDS DEVELOP EVEN THOUGH MODELS SAY NO. WILL WARM UP
MAXES SOME AT THIS TIME.
.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 1142 PM MST WED NOV 21 2012
SHORTWAVE TROUGH WILL MOVE FROM THE NORTHERN ROCKIES TO THE
CENTRAL PLAINS SUNDAY NIGHT AND MONDAY. MODEL SOLUTIONS CONTINUE TO
RETREAT FROM PRECIPITATION CHANCES...AND ITS LOOKING LIKE LITTLE
TO NONE IN THE LOCAL AREA. COLDER AIR WILL MOVE IN BEHIND THE COLD
FRONT SUNDAY NIGHT BUT COOL DOWN WILL BE SHORT LIVED. UPPER RIDGE
WILL QUICKLY REBUILD OVER THE GREAT BASIN EARLY IN THE WEEK THEN
ROCKIES BY MID WEEK. TEMPERATURES WILL RETURN TO ABOVE NORMAL BY
TUESDAY WITH NO PRECIPITATION CHANCES.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 415 AM MST THU NOV 22 2012
VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD. COLD FRONT WILL
MOVE THROUGH THE AREA THIS MORNING. AS IT DOES SO...WINDS WILL
INCREASE THROUGH THE MORNING AND BECOME GUSTY. SOME BLOWING DUST
COULD OCCUR BUT DO NOT EXPECT TO BE WIDESPREAD ENOUGH OR TO CREATE
SUB VFR CONDITIONS AT THIS TIME. WINDS ARE NOT EXPECTED TO
DECREASE UNTIL LATE IN THE AFTERNOON AND THEN REMAIN LIGHT THROUGH
THE REST OF THE NIGHT.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...BULLER
LONG TERM...024
AVIATION...BULLER
AREA FORECAST DISCUSSION
NWS GOODLAND KS
226 AM MST THU NOV 22 2012
.SHORT TERM...(TODAY THROUGH SATURDAY NIGHT)
ISSUED AT 226 AM MST THU NOV 22 2012
MAIN FORECAST ISSUE WILL BE THE WINDS TODAY WITH MINOR CONCERNS OF
HOW MUCH IT COOLS OFF THROUGH TOMORROW AND HOW MUCH THE WARM UP IS
ON SATURDAY. SATELLITE SHOWING AN AMPLIFIED PATTERN OVER THE PACIFIC
WITH A LESS AMPLIFIED MORE PROGRESSIVE FLOW FROM NORTH AMERICA INTO
THE ATLANTIC. COLD FRONT IS APPROACHING THE AREA FROM THE NORTHWEST.
AT JET LEVEL...THE ECMWF WAS DOING A LITTLE BETTER THAN THE UKMET...
CANADIAN...AND NAM ON THE JET SEGMENT ASSOCIATED WITH THE NORTHERN
STREAM SYSTEM. THE GFS FOLLOWED BY THE SREF WAS TOO STRONG WITH THE
JET BEHIND THE INCOMING TROUGH. AT MID LEVELS THE MODELS INITIALIZED
FINE WITH NO BIG PROBLEMS. THE RUC AND NAM WERE DOING BEST ON THE
WIND/PRESSURE FIELD. LOW LEVEL THERMAL GUIDANCE WAS CLOSE TO EACH
OTHER AND REALITY.
TODAY/TONIGHT...SATELLITE AND UPPER AIR IS SHOWING A VERY DRY AND
SUBSIDENT AIR MASS BEHIND THE SYSTEM MOVING ALONG THE CANADIAN AND
UNITED STATES BORDER.
SURFACE TO 850 MB WINDS ARE HIGHEST AT 12Z AND THEN DECREASE BY 18Z.
SOME PLACES COULD REACH 35 KNOT GUSTS. HIGHEST OBSERVED 3 HOUR
PRESSURE RISES HAVE OCCURRED MUCH FURTHER NORTH AND ARE NOT ANYTHING
OUT OF THE ORDINARY AT THIS TIME. FORECAST PRESSURE GRADIENT AND 3
HOUR PRESSURE RISES ARE HIGHEST EARLY ON AND DECREASE BY 18Z. IN FACT
BOTH WOULD INDICATE A QUICK BURST OF THE STRONGEST WINDS RIGHT AFTER
THE FROPA AND SUPPORT WINDY CONDITIONS BUT NOT QUITE AT ADVISORY
CRITERIA. STRONGEST SUBSIDENCE LOOKS TO BE NEAR THE NORTHERN PORTION
OF OUR AREA. THAT AND OTHER GUIDANCE WOULD SUPPORT THE HIGHEST WINDS
TO BE IN THE NORTHERN PORTION OF THE AREA AND MAYBE SOME OF THE
SOUTHWEST. SO HAVE CONTINUE TO HAVE WINDS JUST UNDER ADVISORY
CRITERIA WITH THE NORTH THE CLOSEST.
HIGH LEVEL CLOUDS WILL BE THICKEST EARLY DUE TO THE RIGHT REAR
QUADRANT OF THE MID AND UPPER JET BEING CLOSE. OVERNIGHT
TEMPERATURES HAVE BEEN ALL OVER THE PLACE AS THE PREFRONTAL TROUGH
WORKS ITS WAY ACROSS. FRONT LOOKS TO PUSH THROUGH THE AREA EARLY
TODAY. NWP IS WARMER THAN IT WAS YESTERDAY AND IN CLOSE AGREEMENT.
MADE ONLY SLIGHT ADJUSTMENTS.
GUIDANCE THIS MORNING KEEPS THE WINDS STRONGER FOR TONIGHT THAN THE
IT DID YESTERDAY DUE TO THE SURFACE RIDGE MOVING IN A LITTLE
SLOWER. SO WARMED UP THE MINS.
FRIDAY/FRIDAY NIGHT...SHOULD SEE PLENTY OF SUN WITH AREA COMING
UNDER THE CONTROL OF RIDGING/SUBSIDENCE/DRYING. SURFACE HIGH MOVES
ACROSS DURING THE DAY AND IS NOT TOO FAR EAST OF THE AREA BY LATE IN
THE AFTERNOON. NEW GUIDANCE IS CLOSE TO EACH OTHER AND NOT TOO
DIFFERENT FROM ONGOING FORECAST SO MADE LITTLE IF ANY CHANGES. WIND
FIELD STARTS OUT LIGHT BEFORE WAA AND DOWNSLOPE STARTS. TEMPERATURES
COULD FALL RAPIDLY BEFORE THIS GETS GOING.
SATURDAY/SATURDAY NIGHT...AGAIN LOOKS LIKE A LOT OF SUN THROUGH THE
DAY. WINDS STAY LIGHT THROUGH THE DAY BUT MOSTLY FROM A DOWNSLOPE
DIRECTION. NEWER GUIDANCE IS PRETTY CLOSE TO EACH OTHER AND WARMER
THAN CURRENT FORECAST. CONSIDERING THE DEEP/INCREASING WESTERLY FLOW
ALOFT THIS DOES MAKE SENSE. DRY AIR MASS AND DRY GROUND SHOULD ALLOW
A QUICK RESPONSE TO THE EVEN LIGHT DOWNSLOPE WIND. HOWEVER MAY HAVE
SOME WAVE CLOUDS DEVELOP EVEN THOUGH MODELS SAY NO. WILL WARM UP
MAXES SOME AT THIS TIME.
.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 1142 PM MST WED NOV 21 2012
SHORTWAVE TROUGH WILL MOVE FROM THE NORTHERN ROCKIES TO THE
CENTRAL PLAINS SUNDAY NIGHT AND MONDAY. MODEL SOLUTIONS CONTINUE TO
RETREAT FROM PRECIPITATION CHANCES...AND ITS LOOKING LIKE LITTLE
TO NONE IN THE LOCAL AREA. COLDER AIR WILL MOVE IN BEHIND THE COLD
FRONT SUNDAY NIGHT BUT COOL DOWN WILL BE SHORT LIVED. UPPER RIDGE
WILL QUICKLY REBUILD OVER THE GREAT BASIN EARLY IN THE WEEK THEN
ROCKIES BY MID WEEK. TEMPERATURES WILL RETURN TO ABOVE NORMAL BY
TUESDAY WITH NO PRECIPITATION CHANCES.
&&
.AVIATION...FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1026 PM MST WED NOV 21 2012
VFR CONDITIONS ARE EXPECTED FOR THE NEXT 24 HOURS. THE ONLY CLOUD
COVER WILL BE SOME CIRRUS MOVING THROUGH THIS MORNING FROM THE
WEST. OF BIGGER CONCERN FOR AVIATION WILL BE THE WINDS THIS
AFTERNOON. A COLD FRONT AND LEE TROUGH WILL PUSH THROUGH DURING
THE FORECAST PERIOD. A TIGHT PRESSURE GRADIENT AND STRONGER WINDS
ALOFT WILL ALLOW FOR GUSTY NORTH WINDS AT THE SURFACE. WINDS WILL
GRADUALLY PICK UP IN THE MORNING HOURS AND WINDS FOR THE AFTERNOON
HOURS LOOK TO BE SUSTAINED AT AROUND 25 KTS WITH GUSTS TO 35
SUGGESTED BY GUIDANCE. WINDS WILL WEAKEN BY THIS EVENING.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...BULLER
LONG TERM...024
AVIATION...RRH
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1100 PM CST WED NOV 21 2012
...UPDATE TO AVIATION FOR 06Z TAFS...
.SYNOPSIS...
ISSUED AT 1023 PM CST WED NOV 21 2012
THE 22.00Z 250 HPA MAP SHOWED A 100 KT NORTHWESTERLY JET ACROSS THE
PACIFIC NORTHWEST ON THE UPSTREAM SIDE OF A LONGWAVE TROF LOCATED ACROSS
THE NORTHERN ROCKIES. ANOTHER JET STREAK OF AROUND 110 KT WAS FOUND
ON THE BASE OF A VERY AMPLIFIED TROF LOCATED ACROSS FLORIDA AND THE
SW ATLANTIC BASIN. A VERY SUBTLE WIND MAX AROUND 50 KT WAS ALSO OBSERVED
AT KDDC (DODGE CITY, KS). AT 500 HPA, VERY COLD MID LEVEL TEMPS OF -30
DEG C TO -35 DEG C WERE OBSERVED ACROSS THE PACIFIC NORTHWEST. CLOSER
TO HOME, SOME MID LEVEL MOISTURE WAS NOTED ACROSS WEST TEXAS AHEAD OF
A WEAK PRESSURE PERTURBATION. DRY AIR ADVECTION WAS NOTED ACROSS THE
DEEP SOUTH IN THE WAKE OF THE AFOREMENTIONED UL DISTURBANCE. AT 700
HPA, TEMPS WERE WARM ACROSS THE CENTRAL PLAINS FOR NOVEMBER STANDARDS
WITH MANY LOCATIONS REPORTING IN THE 5 DEG C TO 8 DEG C RANGE. THE ATMOSPHERE
WAS FAIRLY DRY IN THIS AREA AS WELL. 850 HPA TEMPS ACROSS THE PLAINS
WERE WARM WITH A DRY/ADIABATICALLY MIXED PROFILE ACROSS KANSAS. TEMPS
AROUND 15 DEG C TO 17 DEG C WERE COMMON FROM WEST TEXAS TO MINNESOTA.
AT THE SFC, TWO FRONTAL SYSTEMS WERE NOTED ACROSS THE NORTHERN PRAIRIES.
A LEE TROUGH WAS ALSO NOTED ACROSS EASTERN COLORADO. A RIDGE AXIS OF
HIGH PRESSURE EXTENDED FROM THE NORTHERN GULF NE TO NEW ENGLAND.
&&
.SHORT TERM...(THIS EVENING THROUGH TOMORROW)
ISSUED AT 343 PM CST WED NOV 21 2012
FOR THE TIME PERIOD TONIGHT AND TOMORROW, THE GREATEST CHALLENGE IN
THE FORECAST WILL BE LOWS TONIGHT AND HOW MUCH CLOUD COVER AND WIND
WILL INFLUENCE OVERNIGHT TEMPERATURES. THE PREVIOUS FORECAST
ALREADY HAD A FAIRLY TIGHT GRADIENT IN LOW TEMPERATURES TONIGHT
(FROM 33F ACROSS FAR WEST CENTRAL KANSAS TO AROUND 51F ACROSS FAR
SOUTH CENTRAL KANSAS). THESE LOOK GOOD FOR THE MOST PART, BUT THE
LATEST RAP AND NAM12 MODELS SUGGEST TEMPERATURES WILL NOT GET MUCH
BELOW 60F SOUTHEAST OF A GREAT BEND TO ASHLAND LINE, AND GIVEN THE
SEMI OPAQUE SKY COVER FROM 300-500MB CLOUD (FROM THE SUBTROPICAL
SHORTWAVE TROUGH) AND THE SOUTHWEST WINDS CONTINUING 12 TO 16 KNOTS
IN THESE AREAS, REALLY CANNOT ARGUE AGAINST THESE WARM TEMPERATURES
TONIGHT. AS A RESULT, I HAVE BUMPED UP MIN TEMPS ABOUT 2 TO 4
DEGREES AND MOVED THE GRADIENT WESTWARD ABOUT 30 MILES OR SO
(EFFECTIVELY WARMING UP DODGE CITY LOW QUITE A BIT).
THE FORECAST FOR THANKSGIVING DAY WILL BE A LITTLE LESS COMPLICATED
AS MID-HIGH LEVEL CLOUD COVER WILL BE MOVING EAST OF THE AREA WITH
SURFACE WINDS BECOMING NORTHWESTERLY. WHILE COLD ADVECTION WILL
EXIST BEHIND THE FRONT, THE AIRMASS WILL BE MODIFIED BY DOWNSLOPE
AND INSOLATION WILL ALSO COUNTER THE COLD ADVECTION. HIGHS WILL
STILL BE ABOVE AVERAGE FOR THE DATE WITH TEMPERATURES WARMING INTO
THE 60S (LOWER 70S SOUTH CENTRAL KS). WITH THE INITIAL ISALLOBARIC
WIND SURGE/PRESSURE RISE WITH THE PASSAGE OF THE FRONT, WIND SPEEDS
WILL BE 22 TO 26 KNOTS MUCH LIKE TODAY, BUT THESE SPEEDS SHOULD ONLY
OCCUR DURING ABOUT A 3 OR 4 HOUR PERIOD BEFORE WINDS GRADUALLY
DECREASE BACK DOWN TO THE 18 TO 22 KT RANGE LATE IN THE DAY.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 248 PM CST WED NOV 21 2012
BY THE BEGINNING OF THE EXTENDED PERIOD ON THURSDAY NIGHT, A STRONG
UPPER LEVEL SHORTWAVE TROUGH WILL BE MOVING OUT OF THE NORTHERN
PLAINS INTO THE MIDWESTERN STATES AND GREAT LAKES REGION. A COLD
FRONT WILL BE LOCATED OVER SOUTHEAST KANSAS INTO WEST TEXAS. HIGH
PRESSURE WILL BE BUILDING INTO WESTERN KANSAS BEHIND THE FRONT
THURSDAY NIGHT THROUGH FRIDAY. THE 12Z MODEL TEMPERATURE FORECASTS
ARE COMING IN COOLER THAN PREVIOUS RUNS WHICH SEEMS REASONABLE GIVEN
THE ONGOING COLD AIR ADVECTION.
INTO THIS WEEKEND, FLAT UPPER LEVEL RIDGING WILL SPREAD EAST ACROSS
THE WESTERN AND CENTRAL PART OF THE COUNTRY. ANOTHER SHORTWAVE
TROUGH WILL MOVE INTO THE PACIFIC NORTHWEST ON SATURDAY BEHIND THE
RIDGE AND THIS FEATURE WILL BE DIGGING SOME AS IT MOVES INTO THE
CENTRAL HIGH PLAINS BY MONDAY NIGHT. THROUGH THIS WEEKEND THE DRY
FORECAST WILL CONTINUE WITH TEMPERATURES WILL MODERATE BACK INTO THE
60S. LEE SIDE TROUGHING WILL DEVELOP ON SATURDAY. THIS WILL DEVELOP
INTO A LOW PRESSURE AREA THAT MOVES INTO THE OKLAHOMA AND TEXAS
PANHANDLES BY SUNDAY EVENING AS THE NEXT UPPER TROUGH APPROACHES.
THIS WILL BRING A SWITCH IN THE SURFACE WINDS BACK AROUND TO THE
EAST TO NORTHEAST ON SUNDAY. THIS WAVE WILL MOVE OUT ACROSS THE
CENTRAL AND NORTHERN PLAINS MONDAY NIGHT. THERE DOES NOT APPEAR TO
BE SUFFICIENT MOISTURE AVAILABLE FOR THIS SYSTEM TO WORK WITH. THE
BEST CHANCES FOR MEASURABLE PRECIPITATION WILL BE ALONG THE EASTERN
SLOPES OF THE ROCKIES AND OVER EASTERN KANSAS INTO THE MID
MISSISSIPPI VALLEY. HIGH TEMPERATURES WILL DROP BACK INTO THE 40S ON
MONDAY AND TUESDAY.
THE REMAINDER OF THE EXTENDED PERIOD WILL SEE AN UPPER LEVEL RIDGE
BUILDING OVER THE CENTRAL PART OF THE COUNTRY. THIS WILL RESULT IN
TEMPERATURES MODERATING BACK INTO THE 60S LATER NEXT WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1100 PM CST WED NOV 21 2012
A COLD FRONT WILL TRAVERSE ACROSS THE REGION THIS MORNING. WINDS WILL
INCREASE NORTHERLY 20-25 KT THROUGH LATE MORNING INTO THE EARLY AFTERNOON
VIA MIXING/MOMENTUM TRANSFER DOWNWARD. WINDS WILL DECREASE 10-15 KT BY
DUSK. OTHER THAN SOME MID TO HIGH LEVEL CLOUDS, CIGS WILL REMAIN VFR.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 52 66 24 53 / 0 0 0 0
GCK 41 64 22 53 / 0 0 0 0
EHA 41 65 23 53 / 0 0 0 0
LBL 47 67 24 55 / 0 0 0 0
HYS 42 63 21 51 / 0 0 0 0
P28 55 72 28 53 / 10 10 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...SUGDEN
SHORT TERM...UMSCHEID
LONG TERM...GERARD
AVIATION...SUGDEN
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1023 PM CST WED NOV 21 2012
...UPDATE TO SYNOPSIS...
.SYNOPSIS...
ISSUED AT 1023 PM CST WED NOV 21 2012
THE 22.00Z 250 HPA MAP SHOWED A 100 KT NORTHWESTERLY JET ACROSS THE
PACIFIC NORTHWEST ON THE UPSTREAM SIDE OF A LONGWAVE TROF LOCATED ACROSS
THE NORTHERN ROCKIES. ANOTHER JET STREAK OF AROUND 110 KT WAS FOUND
ON THE BASE OF A VERY AMPLIFIED TROF LOCATED ACROSS FLORIDA AND THE
SW ATLANTIC BASIN. A VERY SUBTLE WIND MAX AROUND 50 KT WAS ALSO OBSERVED
AT KDDC (DODGE CITY, KS). AT 500 HPA, VERY COLD MID LEVEL TEMPS OF -30
DEG C TO -35 DEG C WERE OBSERVED ACROSS THE PACIFIC NORTHWEST. CLOSER
TO HOME, SOME MID LEVEL MOISTURE WAS NOTED ACROSS WEST TEXAS AHEAD OF
A WEAK PRESSURE PERTURBATION. DRY AIR ADVECTION WAS NOTED ACROSS THE
DEEP SOUTH IN THE WAKE OF THE AFOREMENTIONED UL DISTURBANCE. AT 700
HPA, TEMPS WERE WARM ACROSS THE CENTRAL PLAINS FOR NOVEMBER STANDARDS
WITH MANY LOCATIONS REPORTING IN THE 5 DEG C TO 8 DEG C RANGE. THE ATMOSPHERE
WAS FAIRLY DRY IN THIS AREA AS WELL. 850 HPA TEMPS ACROSS THE PLAINS
WERE WARM WITH A DRY/ADIABATICALLY MIXED PROFILE ACROSS KANSAS. TEMPS
AROUND 15 DEG C TO 17 DEG C WERE COMMON FROM WEST TEXAS TO MINNESOTA.
AT THE SFC, TWO FRONTAL SYSTEMS WERE NOTED ACROSS THE NORTHERN PRAIRIES.
A LEE TROUGH WAS ALSO NOTED ACROSS EASTERN COLORADO. A RIDGE AXIS OF
HIGH PRESSURE EXTENDED FROM THE NORTHERN GULF NE TO NEW ENGLAND.
&&
.SHORT TERM...(THIS EVENING THROUGH TOMORROW)
ISSUED AT 343 PM CST WED NOV 21 2012
FOR THE TIME PERIOD TONIGHT AND TOMORROW, THE GREATEST CHALLENGE IN
THE FORECAST WILL BE LOWS TONIGHT AND HOW MUCH CLOUD COVER AND WIND
WILL INFLUENCE OVERNIGHT TEMPERATURES. THE PREVIOUS FORECAST
ALREADY HAD A FAIRLY TIGHT GRADIENT IN LOW TEMPERATURES TONIGHT
(FROM 33F ACROSS FAR WEST CENTRAL KANSAS TO AROUND 51F ACROSS FAR
SOUTH CENTRAL KANSAS). THESE LOOK GOOD FOR THE MOST PART, BUT THE
LATEST RAP AND NAM12 MODELS SUGGEST TEMPERATURES WILL NOT GET MUCH
BELOW 60F SOUTHEAST OF A GREAT BEND TO ASHLAND LINE, AND GIVEN THE
SEMI OPAQUE SKY COVER FROM 300-500MB CLOUD (FROM THE SUBTROPICAL
SHORTWAVE TROUGH) AND THE SOUTHWEST WINDS CONTINUING 12 TO 16 KNOTS
IN THESE AREAS, REALLY CANNOT ARGUE AGAINST THESE WARM TEMPERATURES
TONIGHT. AS A RESULT, I HAVE BUMPED UP MIN TEMPS ABOUT 2 TO 4
DEGREES AND MOVED THE GRADIENT WESTWARD ABOUT 30 MILES OR SO
(EFFECTIVELY WARMING UP DODGE CITY LOW QUITE A BIT).
THE FORECAST FOR THANKSGIVING DAY WILL BE A LITTLE LESS COMPLICATED
AS MID-HIGH LEVEL CLOUD COVER WILL BE MOVING EAST OF THE AREA WITH
SURFACE WINDS BECOMING NORTHWESTERLY. WHILE COLD ADVECTION WILL
EXIST BEHIND THE FRONT, THE AIRMASS WILL BE MODIFIED BY DOWNSLOPE
AND INSOLATION WILL ALSO COUNTER THE COLD ADVECTION. HIGHS WILL
STILL BE ABOVE AVERAGE FOR THE DATE WITH TEMPERATURES WARMING INTO
THE 60S (LOWER 70S SOUTH CENTRAL KS). WITH THE INITIAL ISALLOBARIC
WIND SURGE/PRESSURE RISE WITH THE PASSAGE OF THE FRONT, WIND SPEEDS
WILL BE 22 TO 26 KNOTS MUCH LIKE TODAY, BUT THESE SPEEDS SHOULD ONLY
OCCUR DURING ABOUT A 3 OR 4 HOUR PERIOD BEFORE WINDS GRADUALLY
DECREASE BACK DOWN TO THE 18 TO 22 KT RANGE LATE IN THE DAY.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 248 PM CST WED NOV 21 2012
BY THE BEGINNING OF THE EXTENDED PERIOD ON THURSDAY NIGHT, A STRONG
UPPER LEVEL SHORTWAVE TROUGH WILL BE MOVING OUT OF THE NORTHERN
PLAINS INTO THE MIDWESTERN STATES AND GREAT LAKES REGION. A COLD
FRONT WILL BE LOCATED OVER SOUTHEAST KANSAS INTO WEST TEXAS. HIGH
PRESSURE WILL BE BUILDING INTO WESTERN KANSAS BEHIND THE FRONT
THURSDAY NIGHT THROUGH FRIDAY. THE 12Z MODEL TEMPERATURE FORECASTS
ARE COMING IN COOLER THAN PREVIOUS RUNS WHICH SEEMS REASONABLE GIVEN
THE ONGOING COLD AIR ADVECTION.
INTO THIS WEEKEND, FLAT UPPER LEVEL RIDGING WILL SPREAD EAST ACROSS
THE WESTERN AND CENTRAL PART OF THE COUNTRY. ANOTHER SHORTWAVE
TROUGH WILL MOVE INTO THE PACIFIC NORTHWEST ON SATURDAY BEHIND THE
RIDGE AND THIS FEATURE WILL BE DIGGING SOME AS IT MOVES INTO THE
CENTRAL HIGH PLAINS BY MONDAY NIGHT. THROUGH THIS WEEKEND THE DRY
FORECAST WILL CONTINUE WITH TEMPERATURES WILL MODERATE BACK INTO THE
60S. LEE SIDE TROUGHING WILL DEVELOP ON SATURDAY. THIS WILL DEVELOP
INTO A LOW PRESSURE AREA THAT MOVES INTO THE OKLAHOMA AND TEXAS
PANHANDLES BY SUNDAY EVENING AS THE NEXT UPPER TROUGH APPROACHES.
THIS WILL BRING A SWITCH IN THE SURFACE WINDS BACK AROUND TO THE
EAST TO NORTHEAST ON SUNDAY. THIS WAVE WILL MOVE OUT ACROSS THE
CENTRAL AND NORTHERN PLAINS MONDAY NIGHT. THERE DOES NOT APPEAR TO
BE SUFFICIENT MOISTURE AVAILABLE FOR THIS SYSTEM TO WORK WITH. THE
BEST CHANCES FOR MEASURABLE PRECIPITATION WILL BE ALONG THE EASTERN
SLOPES OF THE ROCKIES AND OVER EASTERN KANSAS INTO THE MID
MISSISSIPPI VALLEY. HIGH TEMPERATURES WILL DROP BACK INTO THE 40S ON
MONDAY AND TUESDAY.
THE REMAINDER OF THE EXTENDED PERIOD WILL SEE AN UPPER LEVEL RIDGE
BUILDING OVER THE CENTRAL PART OF THE COUNTRY. THIS WILL RESULT IN
TEMPERATURES MODERATING BACK INTO THE 60S LATER NEXT WEEK.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 505 PM CST WED NOV 21 2012
VFR CONDITIONS WILL PREVAIL AT ALL TAF SITES THROUGH EARLY
THURSDAY AFTERNOON. AS FOR WINDS, A LEE SIDE TROUGH OF LOW
PRESSURE IN EXTREME EASTERN COLORADO WILL BEGIN EDGING EAST
INTO WESTERN KANSAS THIS EVENING. AS A RESULT, SOUTHERLY WINDS
OF 15 TO 25KT EARLY THIS EVENING WILL BECOME MORE SOUTHWESTERLY
WHILE DECREASING 5 TO 15KT OVERNIGHT. A COLD FRONT IS THEN
EXPECTED TO PUSH SOUTHEAST ACROSS WESTERN KANSAS EARLY THURSDAY
MORNING TURNING WINDS NORTHERLY 25 TO 35KT BY MID DAY THURSDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 52 66 24 53 / 0 0 0 0
GCK 41 64 22 53 / 0 0 0 0
EHA 41 65 23 53 / 0 0 0 0
LBL 47 67 24 55 / 0 0 0 0
HYS 42 63 21 51 / 0 0 0 0
P28 55 72 28 53 / 10 10 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...SUGDEN
SHORT TERM...UMSCHEID
LONG TERM...GERARD
AVIATION...JJOHNSON
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1243 PM EST THU NOV 22 2012
.SYNOPSIS...
ISSUED AT 341 AM EST THU NOV 22 2012
A WINDY AND WARM THANKSGIVING DAY IS ON TAP FOR LOWER MICHIGAN.
TEMPERATURES WILL WARM INTO THE LOWER 60S AS GUSTY SOUTHERLY WINDS
BRING THE WARM AIR UP INTO MICHIGAN. THE WARMER AIR WILL BE SHORT
LIVED HOWEVER AS A STRONG COLD FRONT WILL MOVE THROUGH THE AREA LATE
TONIGHT. RAIN SHOWERS AND EVEN A SLIGHT CHANCE OF A RUMBLE OF
THUNDER WILL BE POSSIBLE.
THE COLDER AIR WILL FILTER INTO THE AREA DURING THE DAY ON FRIDAY.
TEMPERATURES WILL FALL THROUGH THE DAY INTO THE 30S. RAIN SHOWERS
WILL CHANGE OVER TO SNOW SHOWERS. SOME LIGHT ACCUMULATIONS WILL BE
POSSIBLE FOR THE LAKESHORE COMMUNITIES.
&&
.UPDATE...
ISSUED AT 1122 AM EST THU NOV 22 2012
I DID SOME SIGNIFICANT GRID UPDATES LATE THIS MORNING. I UPDATED
THE START OF THE GALE WARNING AND I INCREASED THE POP FOR BOTH
TONIGHT AND FRIDAY.
BASED ON THE LATEST DATA FROM BOTH THE NAM12 AND HRRR IT SEEMS TO ME
THE WINDS WILL RAMP UP SOONER OVER LAKE MICHIGAN AND OUR NEAR
SHORE WATERS. THE NAM12 SOUNDING AT MKG...BIV...LDM AND THE SOUTH
BUOY SHOW 40 TO 45 KNOTS IN THE MIX LAYER BY 21Z. CLOUDS MAY BE AN
ISSUE BUT AT 21Z I COULD SEE THERE NOT BEING A LOT OF CLOUDS YET.
AS A RESULT I BROUGHT FORWARD IN TIME THE START OF THE GALE
WARNING TO 4 PM FROM 10 PM.
THE NAM12 IS NOW SHOWING DEEPER MOISTURE FOR BOTH THE
PRECIPITATION EVENT TONIGHT AND THE LAKE ENHANCED SNOW FOR FRIDAY
AFTERNOON INTO SATURDAY MORNING. FOR THE MOST PART MY POP GRID IS
REALLY BASED ON THE LIFT IN THE SATURATED DGZ GRID FROM THE NAM12.
THAT HAS TIME AND AGAIN SHOWN ME TO BE THE MOST RELIABLE TOOL FOR
FORECASTING PRECIPITATION (RAIN/SNOW AND EVEN TIMING OF
THUNDERSTORMS IF THAT IS APPROPRIATE). THE SOUTHERN STREAM
MOISTURE (SEEN WELL ON THE WATER VAPOR LOOPS) IS STREAMING
NORTHEAST AND WILL RUN INTO THE FRONTAL ZONE LIFT BY MID
AFTERNOON. THIS SHOULD HAVE NO PROBLEM SPARKING SHOWERS AND
ISOLATED THUNDERSTORMS AS THERE IS A 50 - 70 KNOT LOW LEVEL JET
WITH PRECIPITABLE WATER VALUES OVER 300 PCT OF NORMAL JUST AHEAD
OF THE FRONT. I SEE NO REASON WHY I SHOULD NOT GO CONDITIONAL
GIVEN THE DEEP MOISTURE...STRONG LIFT AND STRONG FRONT WITH A GOOD
SOUTHERN STREAM SHORTWAVE.
AS FOR FRIDAY... THERE IS NOW BETTER LIFT IN THE DGZ ON THE NAM12
FOR THE LAKE EFFECT SNOW EVENT FRIDAY INTO FRIDAY NIGHT. I HAVE TO
LOOK AT THIS MORE CLOSELY BY WE MAY HAVE TO INCREASE SNOWFALL
AMOUNTS.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 341 AM EST THU NOV 22 2012
MAIN CHALLENGES IN THE SHORT TERM PORTION OF THE FCST REVOLVE AROUND
RAIN CHANCES TONIGHT...AND LAKE EFFECT TRENDS FRI THROUGH SAT. THE
ONLY REAL CHANGE TO THE FCST WAS TO SLIP A SLIGHT CHC MENTION OF
THUNDER IN THE FCST FOR LATE THIS AFTERNOON AND EVENING.
MANY OBSERVATIONS THIS MORNING ARE TRYING TO DROP THE VISIBILITIES
IN FOG. SITES ARE DOWN TO BETWEEN 1-4SM. THEY HAVE STABILIZED AS IT
APPEARS THE WINDS ALOFT...AND RESIDUAL BREEZE AT THE SURFACE ARE
KEEPING CONDITIONS FROM DROPPING TOO MUCH. WE DO NOT EXPECT TO HAVE
TO ISSUE ANY FOG HEADLINES THIS MORNING.
THE FIRST 2/3RDS OF THE DAY TODAY LOOKS QUITE NICE. WE SHOULD SEE A
GOOD DEAL OF SUNSHINE INTO THE FIRST PORTION OF THE AFTERNOON WITH
ONLY SOME HIGH CLOUDS MOVING THROUGH. IT WILL BE BREEZY WITH WIND
GUSTS APPROACHING 30 MPH IF NOT ECLIPSING IT AT TIMES. WE WILL SEE
THE MOISTURE TRANSPORT PICK UP SIGNIFICANTLY BETWEEN 18Z AND 00Z
TONIGHT AS THE LOW LEVEL JET AXIS MOVES OVERHEAD. WE SHOULD SEE THE
MOSTLY SUNNY SKIES TURN MOSTLY CLOUDY PRETTY QUICK LATER THIS
AFTERNOON. DEEP ENOUGH MOISTURE IS FOUND ACROSS THE WRN COUNTIES
WHERE ANY RAIN THAT FORMS COULD REACH THE GROUND BY 00Z.
THE BEST THREAT OF RAIN WILL COME BETWEEN 00Z AND 09Z TONIGHT...AND
ACROSS THE SE 2/3RDS OF THE CWFA. THIS IS WHERE THE DEEPEST MOISTURE
COMES TOGETHER DUE TO THE WAY THE UPPER MOISTURE ADVECTS INTO THE
AREA AHEAD OF THE WAVE. AS MENTIONED ABOVE...WE HAVE ADDED THUNDER
TO THE FCST. MODELS ARE INDICATING A LITTLE MORE ELEVATED
INSTABILITY PRESENT THAN 24 HOURS AGO. SEVERE THREAT SHOULD REMAIN
RATHER LOW DUE TO THE GENERAL NATURE OF THE ELEVATED INSTABILITY.
THE STRONG LOW LEVEL JET IS SOME CAUSE FOR CONCERN AS IT WOULDN/T
TAKE MUCH TO MIX IT DOWN. HOWEVER...ONCE AGAIN THE ELEVATED NATURE
OF THE INSTABILITY SHOULD LIMIT THE SEVERE POTENTIAL.
WE WILL SEE THE DRY SLOT TRAVERSE THE AREA BETWEEN 09Z AND 15Z FRI.
AFTER 15Z...WE SEE THE WRAP AROUND MOISTURE ROTATE BACK IN ACROSS
THE AREA. H850 TEMPS DROP PRETTY QUICK AT THIS TIME TO EVENTUALLY
AROUND -10C. WE EXPECT THAT THE WRAP AROUND MOISTURE WILL START OUT
AS SOME RAIN AND/OR SNOW SHOWERS THAT WILL TRANSITION TO ALL SNOW
SHOWERS PRETTY QUICKLY.
A FEW SCATTERED SYNOPTIC SNOW SHOWERS WILL REMAIN POSSIBLE. THE
FOCUS WILL TURN ON LAKE EFFECT BY LATE FRI AFTERNOON. DELTA T/S WILL
BE APPROACHING 20C. WE WILL HAVE CYCLONIC FLOW ALOFT. MOISTURE WILL
BE SOMEWHAT LIMITED...WITH INVERSION HEIGHTS AROUND 7-8K FT. THE
BEST LIFT IS BELOW THE DGZ SO WE DO NOT EXPECT SIGNIFICANT SNOW
RATES. THE FLOW WILL TRANSITION FROM WNW TO PURE NW BY 00Z SAT. THIS
WILL LAST INTO THE FIRST HALF OF SAT. WE ARE EXPECTING THAT A COUPLE
OF LOCATIONS MAY SEE AN INCH OR TWO FROM LATE FRI INTO MIDDAY SAT.
THE UPPER LOW WILL LIFT OUT OF THE AREA SAT AFTERNOON. THE UPPER
FLOW BECOMES ANTI-CYCLONIC BY 18Z...LIMITING THE MOISTURE DEPTH
QUITE A BIT. WE SHOULD SEE SNOW SHOWERS DIMINISH BY SAT
AFTERNOON...AND ANYTHING LEFT SPREADING INLAND ONCE AGAIN WITH THE
WRLY WIND SETTING UP WITH THE SFC HIGH MOVING THOUGH.
.LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 341 AM EST THU NOV 22 2012
MODEL DISCREPANCIES CONTINUE IN THE LONG TERM PERIOD...ESPECIALLY IN
REGARD TO WHAT WOULD BE THE MOST SIGNIFICANT PRECIPITATION POTENTIAL
DURING THE PERIOD...THE SYSTEM FOR NEXT TUESDAY.
FIRST THOUGH A WEAK SYSTEM WILL PROGRESS EAST ACROSS THE NORTHERN
GREAT LAKES SATURDAY NIGHT INTO SUNDAY. COULD BE A LITTLE LIGHT SNOW
ACROSS CENTRAL LOWER...BUT NOT EXPECTING MUCH.
FOCUS THEN SHIFTS TO A POTENTIAL SYSTEM FOR TUESDAY INTO TUESDAY
NIGHT. THE GFS HAS A STRONGER MORE NORTHERN TRACK...WHILE THE ECMWF
WOULD BE WELL SOUTH AND WEAKER. AT THIS POINT CONFIDENCE IS NOT HIGH
IN WHICH SOLUTION IS MOST LIKELY TO VERIFY. GIVEN THE TYPICALLY
BETTER TRACK RECORD OF THE ECMWF IN THE 4-7 DAY PERIOD WOULD LEAN
TOWARD THE DRIER SOLUTION. THE GFS WOULD YIELD ACCUMULATING SNOW
ACROSS THE FORECAST AREA. CHANCE POPS IN THE FORECAST AT THIS POINT.
INTO WEDNESDAY THE ECMWF BRINGS A SHORTWAVE THROUGH ACCOMPANIED BY
SOME LIGHT SNOW AND LAKE ENHANCEMENT. MODEL DISCREPANCIES CONTINUE
INTO THIS TIME FRAME WITH THE GFS INDICATING DRY WX.
SUFFICE IT TO SAY AN OVERALL LOW CONFIDENCE FORECAST IN THE LONG
TERM. TEMPERATURES LOOK TO BE BELOW NORMAL THROUGH THE PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1243 PM EST THU NOV 22 2012
MAIN AVIATION CONCERN THROUGH THIS AFTERNOON WILL BE THE
SOUTHERLY WINDS WHICH WILL GUST 20 TO 25 KTS. THESE ARE EXPECTED
TO TAPER OFF SOMEWHAT BY NIGHTFALL.
A STRONG COLD WILL BRING IN LOWER CEILINGS ALONG WITH RAIN SHOWERS
AND EVEN MORE WIND LATE TONIGHT. DUE TO THE AMOUNT OF MIXING
EXPECTED...MOST LOCATIONS WILL ONLY DIP DOWN TO MVFR WITH VERY
PATCHY IFR NEAR AND JUST BEHIND THE FRONT. CAN NOT COMPLETELY RULE
OUT A THUNDERSTORM WITH THE FRONT...BUT HAVE LEFT THAT OUT OF THE
TAFS AS ANY THUNDER SHOULD REMAIN VERY ISOLATED.
A DRY SLOT IS EXPECTED TO ROLL IN AROUND DAYBREAK. SO WE WILL
LIKELY SEE A PERIOD OF HIGHER CEILINGS AND VSBYS WITH THIS.
HOWEVER AS COLDER AIR EVADES THE REGION THROUGH THE MID FRI MORNING
HOURS LAKE EFFECT CLOUDS AND SNOW SHOWERS CAN BE EXPECTED. WITH
WNW FLOW EXPECT SOME AREAS OF IFR TO DEVELOP IN LOWERING VSBYS
AFTER ABOUT 14-16Z FRI.
&&
.MARINE...
ISSUED AT 1122 AM EST THU NOV 22 2012
I BROUGHT FORWARD IN TIME THE START OF THE GALE WARING FROM 10 PM
TO 4 PM. THIS IDEA IS BASED ON THE LATEST DATA FROM BOTH THE
NAM12 AND HRRR IT SEEMS TO ME THE WINDS WILL RAMP UP SOONER OVER
LAKE MICHIGAN AND OUR NEAR SHORE WATERS. THE NAM12 SOUNDING AT
MKG...BIV...LDM AND THE SOUTH BUOY SHOW 40 TO 45 KNOTS IN THE MIX
LAYER BY 21Z. CLOUDS MAY BE AN ISSUE BUT AT 21Z I COULD SEE THERE
NOT BEING A LOT OF CLOUDS YET. AS A RESULT I BROUGHT FORWARD IN
TIME THE START OF THE GALE WARNING TO 4 PM FROM 10 PM.
&&
.HYDROLOGY...
ISSUED AT 341 AM EST THU NOV 22 2012
WE CONTINUE TO EXPECT NO HYDROLOGY ISSUES THROUGH THIS FCST PERIOD.
WE ARE EXPECTING A QUICK SHOT OF RAINFALL WITH THE FRONT VERY LATE
TODAY AND MORE SO TONIGHT. RAINFALL AMOUNTS SHOULD RANGE FROM A
TENTH OR TWO UP NORTH...UP TO AS MUCH AS HALF AN INCH. RIVER AND
STREAM LEVELS CONTINUE TO FLOW BELOW AVERAGE. SOME LAKE EFFECT SNOW
SHOWERS WILL BE AROUND FRIDAY...BUT THIS SHOULD NOT HAVE A LOT OF
WATER CONTENT IN IT. MINIMAL RISES CAN BE EXPECTED.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
LMZ844>849.
GALE WARNING FROM 4 PM THIS AFTERNOON TO 10 PM EST FRIDAY FOR
LMZ844>849.
&&
$$
UPDATE...WDM
SYNOPSIS...NJJ
SHORT TERM...NJJ
LONG TERM...DUKE
AVIATION...JK
HYDROLOGY...NJJ
MARINE...WDM
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1122 AM EST THU NOV 22 2012
.SYNOPSIS...
ISSUED AT 341 AM EST THU NOV 22 2012
A WINDY AND WARM THANKSGIVING DAY IS ON TAP FOR LOWER MICHIGAN.
TEMPERATURES WILL WARM INTO THE LOWER 60S AS GUSTY SOUTHERLY WINDS
BRING THE WARM AIR UP INTO MICHIGAN. THE WARMER AIR WILL BE SHORT
LIVED HOWEVER AS A STRONG COLD FRONT WILL MOVE THROUGH THE AREA LATE
TONIGHT. RAIN SHOWERS AND EVEN A SLIGHT CHANCE OF A RUMBLE OF
THUNDER WILL BE POSSIBLE.
THE COLDER AIR WILL FILTER INTO THE AREA DURING THE DAY ON FRIDAY.
TEMPERATURES WILL FALL THROUGH THE DAY INTO THE 30S. RAIN SHOWERS
WILL CHANGE OVER TO SNOW SHOWERS. SOME LIGHT ACCUMULATIONS WILL BE
POSSIBLE FOR THE LAKESHORE COMMUNITIES.
&&
.UPDATE...
ISSUED AT 1122 AM EST THU NOV 22 2012
I DID SOME SIGNIFICANT GRID UPDATES LATE THIS MORNING. I UPDATED
THE START OF THE GALE WARNING AND I INCREASED THE POP FOR BOTH
TONIGHT AND FRIDAY.
BASED ON THE LATEST DATA FROM BOTH THE NAM12 AND HRRR IT SEEMS TO ME
THE WINDS WILL RAMP UP SOONER OVER LAKE MICHIGAN AND OUR NEAR
SHORE WATERS. THE NAM12 SOUNDING AT MKG...BIV...LDM AND THE SOUTH
BUOY SHOW 40 TO 45 KNOTS IN THE MIX LAYER BY 21Z. CLOUDS MAY BE AN
ISSUE BUT AT 21Z I COULD SEE THERE NOT BEING A LOT OF CLOUDS YET.
AS A RESULT I BROUGHT FORWARD IN TIME THE START OF THE GALE
WARNING TO 4 PM FROM 10 PM.
THE NAM12 IS NOW SHOWING DEEPER MOISTURE FOR BOTH THE
PRECIPITATION EVENT TONIGHT AND THE LAKE ENHANCED SNOW FOR FRIDAY
AFTERNOON INTO SATURDAY MORNING. FOR THE MOST PART MY POP GRID IS
REALLY BASED ON THE LIFT IN THE SATURATED DGZ GRID FROM THE NAM12.
THAT HAS TIME AND AGAIN SHOWN ME TO BE THE MOST RELIABLE TOOL FOR
FORECASTING PRECIPITATION (RAIN/SNOW AND EVEN TIMING OF
THUNDERSTORMS IF THAT IS APPROPRIATE). THE SOUTHERN STREAM
MOISTURE (SEEN WELL ON THE WATER VAPOR LOOPS) IS STREAMING
NORTHEAST AND WILL RUN INTO THE FRONTAL ZONE LIFT BY MID
AFTERNOON. THIS SHOULD HAVE NO PROBLEM SPARKING SHOWERS AND
ISOLATED THUNDERSTORMS AS THERE IS A 50 - 70 KNOT LOW LEVEL JET
WITH PRECIPITABLE WATER VALUES OVER 300 PCT OF NORMAL JUST AHEAD
OF THE FRONT. I SEE NO REASON WHY I SHOULD NOT GO CONDITIONAL
GIVEN THE DEEP MOISTURE...STRONG LIFT AND STRONG FRONT WITH A GOOD
SOUTHERN STREAM SHORTWAVE.
AS FOR FRIDAY... THERE IS NOW BETTER LIFT IN THE DGZ ON THE NAM12
FOR THE LAKE EFFECT SNOW EVENT FRIDAY INTO FRIDAY NIGHT. I HAVE TO
LOOK AT THIS MORE CLOSELY BY WE MAY HAVE TO INCREASE SNOWFALL
AMOUNTS.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 341 AM EST THU NOV 22 2012
MAIN CHALLENGES IN THE SHORT TERM PORTION OF THE FCST REVOLVE AROUND
RAIN CHANCES TONIGHT...AND LAKE EFFECT TRENDS FRI THROUGH SAT. THE
ONLY REAL CHANGE TO THE FCST WAS TO SLIP A SLIGHT CHC MENTION OF
THUNDER IN THE FCST FOR LATE THIS AFTERNOON AND EVENING.
MANY OBSERVATIONS THIS MORNING ARE TRYING TO DROP THE VISIBILITIES
IN FOG. SITES ARE DOWN TO BETWEEN 1-4SM. THEY HAVE STABILIZED AS IT
APPEARS THE WINDS ALOFT...AND RESIDUAL BREEZE AT THE SURFACE ARE
KEEPING CONDITIONS FROM DROPPING TOO MUCH. WE DO NOT EXPECT TO HAVE
TO ISSUE ANY FOG HEADLINES THIS MORNING.
THE FIRST 2/3RDS OF THE DAY TODAY LOOKS QUITE NICE. WE SHOULD SEE A
GOOD DEAL OF SUNSHINE INTO THE FIRST PORTION OF THE AFTERNOON WITH
ONLY SOME HIGH CLOUDS MOVING THROUGH. IT WILL BE BREEZY WITH WIND
GUSTS APPROACHING 30 MPH IF NOT ECLIPSING IT AT TIMES. WE WILL SEE
THE MOISTURE TRANSPORT PICK UP SIGNIFICANTLY BETWEEN 18Z AND 00Z
TONIGHT AS THE LOW LEVEL JET AXIS MOVES OVERHEAD. WE SHOULD SEE THE
MOSTLY SUNNY SKIES TURN MOSTLY CLOUDY PRETTY QUICK LATER THIS
AFTERNOON. DEEP ENOUGH MOISTURE IS FOUND ACROSS THE WRN COUNTIES
WHERE ANY RAIN THAT FORMS COULD REACH THE GROUND BY 00Z.
THE BEST THREAT OF RAIN WILL COME BETWEEN 00Z AND 09Z TONIGHT...AND
ACROSS THE SE 2/3RDS OF THE CWFA. THIS IS WHERE THE DEEPEST MOISTURE
COMES TOGETHER DUE TO THE WAY THE UPPER MOISTURE ADVECTS INTO THE
AREA AHEAD OF THE WAVE. AS MENTIONED ABOVE...WE HAVE ADDED THUNDER
TO THE FCST. MODELS ARE INDICATING A LITTLE MORE ELEVATED
INSTABILITY PRESENT THAN 24 HOURS AGO. SEVERE THREAT SHOULD REMAIN
RATHER LOW DUE TO THE GENERAL NATURE OF THE ELEVATED INSTABILITY.
THE STRONG LOW LEVEL JET IS SOME CAUSE FOR CONCERN AS IT WOULDN/T
TAKE MUCH TO MIX IT DOWN. HOWEVER...ONCE AGAIN THE ELEVATED NATURE
OF THE INSTABILITY SHOULD LIMIT THE SEVERE POTENTIAL.
WE WILL SEE THE DRY SLOT TRAVERSE THE AREA BETWEEN 09Z AND 15Z FRI.
AFTER 15Z...WE SEE THE WRAP AROUND MOISTURE ROTATE BACK IN ACROSS
THE AREA. H850 TEMPS DROP PRETTY QUICK AT THIS TIME TO EVENTUALLY
AROUND -10C. WE EXPECT THAT THE WRAP AROUND MOISTURE WILL START OUT
AS SOME RAIN AND/OR SNOW SHOWERS THAT WILL TRANSITION TO ALL SNOW
SHOWERS PRETTY QUICKLY.
A FEW SCATTERED SYNOPTIC SNOW SHOWERS WILL REMAIN POSSIBLE. THE
FOCUS WILL TURN ON LAKE EFFECT BY LATE FRI AFTERNOON. DELTA T/S WILL
BE APPROACHING 20C. WE WILL HAVE CYCLONIC FLOW ALOFT. MOISTURE WILL
BE SOMEWHAT LIMITED...WITH INVERSION HEIGHTS AROUND 7-8K FT. THE
BEST LIFT IS BELOW THE DGZ SO WE DO NOT EXPECT SIGNIFICANT SNOW
RATES. THE FLOW WILL TRANSITION FROM WNW TO PURE NW BY 00Z SAT. THIS
WILL LAST INTO THE FIRST HALF OF SAT. WE ARE EXPECTING THAT A COUPLE
OF LOCATIONS MAY SEE AN INCH OR TWO FROM LATE FRI INTO MIDDAY SAT.
THE UPPER LOW WILL LIFT OUT OF THE AREA SAT AFTERNOON. THE UPPER
FLOW BECOMES ANTI-CYCLONIC BY 18Z...LIMITING THE MOISTURE DEPTH
QUITE A BIT. WE SHOULD SEE SNOW SHOWERS DIMINISH BY SAT
AFTERNOON...AND ANYTHING LEFT SPREADING INLAND ONCE AGAIN WITH THE
WRLY WIND SETTING UP WITH THE SFC HIGH MOVING THOUGH.
.LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 341 AM EST THU NOV 22 2012
MODEL DISCREPANCIES CONTINUE IN THE LONG TERM PERIOD...ESPECIALLY IN
REGARD TO WHAT WOULD BE THE MOST SIGNIFICANT PRECIPITATION POTENTIAL
DURING THE PERIOD...THE SYSTEM FOR NEXT TUESDAY.
FIRST THOUGH A WEAK SYSTEM WILL PROGRESS EAST ACROSS THE NORTHERN
GREAT LAKES SATURDAY NIGHT INTO SUNDAY. COULD BE A LITTLE LIGHT SNOW
ACROSS CENTRAL LOWER...BUT NOT EXPECTING MUCH.
FOCUS THEN SHIFTS TO A POTENTIAL SYSTEM FOR TUESDAY INTO TUESDAY
NIGHT. THE GFS HAS A STRONGER MORE NORTHERN TRACK...WHILE THE ECMWF
WOULD BE WELL SOUTH AND WEAKER. AT THIS POINT CONFIDENCE IS NOT HIGH
IN WHICH SOLUTION IS MOST LIKELY TO VERIFY. GIVEN THE TYPICALLY
BETTER TRACK RECORD OF THE ECMWF IN THE 4-7 DAY PERIOD WOULD LEAN
TOWARD THE DRIER SOLUTION. THE GFS WOULD YIELD ACCUMULATING SNOW
ACROSS THE FORECAST AREA. CHANCE POPS IN THE FORECAST AT THIS POINT.
INTO WEDNESDAY THE ECMWF BRINGS A SHORTWAVE THROUGH ACCOMPANIED BY
SOME LIGHT SNOW AND LAKE ENHANCEMENT. MODEL DISCREPANCIES CONTINUE
INTO THIS TIME FRAME WITH THE GFS INDICATING DRY WX.
SUFFICE IT TO SAY AN OVERALL LOW CONFIDENCE FORECAST IN THE LONG
TERM. TEMPERATURES LOOK TO BE BELOW NORMAL THROUGH THE PERIOD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 649 AM EST THU NOV 22 2012
FOG GENERALLY BETWEEN 1-4SM ACROSS THE AREA WILL LIFT FAIRLY QUICK
AFTER SUNRISE. EXPECT ALL SITES TO BE VFR BY 15Z OR SO. SKIES WILL
BE MAINLY CLEAR THROUGH MID AFTERNOON. THE WIND WILL BE THE MAIN
WEATHER ISSUE TODAY WITH SOUTH-SOUTHWEST WINDS OF 13-25 KNOTS
THROUGH THE COURSE OF THE DAY.
RAIN SHOWERS WILL BREAK OUT ACROSS THE AREA BETWEEN 21Z AND
00Z...SPREADING EAST WITH TIME. A RUMBLE OF THUNDER CANNOT BE
RULED OUT BETWEEN 22Z AND 05Z...BUT THE THREAT IS TOO LOW TO
INCLUDE IN THE TAFS AT THIS TIME. CEILINGS WILL BE VFR THIS
EVENING BEFORE DROPPING TO MVFR AFTER 05Z.
&&
.MARINE...
ISSUED AT 1122 AM EST THU NOV 22 2012
I BROUGHT FORWARD IN TIME THE START OF THE GALE WARING FROM 10 PM
TO 4 PM. THIS IDEA IS BASED ON THE LATEST DATA FROM BOTH THE
NAM12 AND HRRR IT SEEMS TO ME THE WINDS WILL RAMP UP SOONER OVER
LAKE MICHIGAN AND OUR NEAR SHORE WATERS. THE NAM12 SOUNDING AT
MKG...BIV...LDM AND THE SOUTH BUOY SHOW 40 TO 45 KNOTS IN THE MIX
LAYER BY 21Z. CLOUDS MAY BE AN ISSUE BUT AT 21Z I COULD SEE THERE
NOT BEING A LOT OF CLOUDS YET. AS A RESULT I BROUGHT FORWARD IN
TIME THE START OF THE GALE WARNING TO 4 PM FROM 10 PM.
&&
.HYDROLOGY...
ISSUED AT 341 AM EST THU NOV 22 2012
WE CONTINUE TO EXPECT NO HYDROLOGY ISSUES THROUGH THIS FCST PERIOD.
WE ARE EXPECTING A QUICK SHOT OF RAINFALL WITH THE FRONT VERY LATE
TODAY AND MORE SO TONIGHT. RAINFALL AMOUNTS SHOULD RANGE FROM A
TENTH OR TWO UP NORTH...UP TO AS MUCH AS HALF AN INCH. RIVER AND
STREAM LEVELS CONTINUE TO FLOW BELOW AVERAGE. SOME LAKE EFFECT SNOW
SHOWERS WILL BE AROUND FRIDAY...BUT THIS SHOULD NOT HAVE A LOT OF
WATER CONTENT IN IT. MINIMAL RISES CAN BE EXPECTED.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
LMZ844>849.
GALE WARNING FROM 4 PM THIS AFTERNOON TO 10 PM EST FRIDAY FOR
LMZ844>849.
&&
$$
UPDATE...WDM
SYNOPSIS...NJJ
SHORT TERM...NJJ
LONG TERM...DUKE
AVIATION...DUKE
HYDROLOGY...NJJ
MARINE...WDM
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
257 AM EST THU NOV 22 2012
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 437 PM EST WED NOV 21 2012
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW UPR RDG EXTENDING
NEWD FM THE SRN PLAINS INTO THE GRT LKS BTWN A TROF ALONG THE E
COAST AND ANOTHER ALONG THE W COAST. THE AIRMASS ALOFT IS QUITE WARM
AND DRY OVER THE UPR GRT LKS...BUT LO CLDS ENHANCED BY RADIATIONAL
COOLING LAST NGT THAT FORMED UNDER SHARP LLVL INVRN SHOWN ON LOCAL
12Z RAOBS ARE PROVING TO BE QUITE RESILIENT OVER THE SCENTRAL AND
ERN CWA WITH ADDED MOISTENING OFF LK MI IN SSW FLOW BTWN HI PRES IN
THE MID ATLANTIC AND LOWER PRES IN THE PLAINS. THERE IS NO FOG/ST
NOTED TO THE W...BUT PLENTY OF HI CLDS ARE STREAMING ENEWD FM THE
PLAINS INTO THE UPR LKS IN THE WSW FLOW ALF. A POTENT SHRTWV IS
COMING ASHORE IN THE PAC NW.
LATE THIS AFTN...LO CLDS PRESENT EARLY THIS AFTN OVER THE SCENTRAL
AND E WILL BREAK UP THRU THE AFTN IN THE PRESENCE OF SOME DIURNAL
HEATING. THESE CLDS WL BE MOST RESILIENT OVER THE FAR E DOWNWIND OF
LK MI AS STLT IMAGERY SHOWS ST DECK EXTENDING ALMOST THE ENTIRE
LENGTH OF THE LK.
TNGT...ALTHOUGH THE ST SHOULD BE GONE THIS EVNG EXCEPT OVER THE FAR
E...SUSPECT THIS LO CLD WL FORM AGAIN TNGT WITH NOCTURNAL COOLING
AND PERSISTENT SSW FLOW/LO INVRN SHOWN ON FCST SDNGS. CONFIDENCE IN
THIS SCENARIO IS HIER SINCE THE 12Z NAM/LOCAL WRF-ARW SHOW HIER
H95-9 SPECIFIC HUMIDITY ADVECTING INTO THE AREA OVERNGT IN THE
STRENGTHENING LLVL SSW FLOW. H925 WINDS AS HI AS 30-40KTS BY LATE
TNGT SHOULD LIMIT THE POTENTIAL FOR DENSER FOG...BUT STILL ADDED
SOME PATCHY FOG OVER THE SCENTRAL AND E AWAY FM MORE PRONOUNCED
DOWNSLOPE WARMING OVER THE NW AND NCENTRAL AS MODELS HINT AT A
PERIOD OF LIGHTER WINDS THIS EVNG THAT MIGHT AUGMENT A PERIOD OF
QUICK COOLING. MIN TEMPS WL REMAIN WELL ABV NORMAL WITH INCRSG
WINDS/ QUITE A BIT OF HI CLD...ESPECIALLY IN THE DOWNSLOPE AREAS
OVER THE W AND NCENTRAL NEAR LK SUP.
THANKSGIVING DAY...WITH DIURNAL HEATING...EXPECT LO CLDS/FOG IN THE
MRNG TO BREAK UP BY NOON. BUT WITH PERSISTENT SSW FLOW...THE ST WL
MOST LIKELY LINGER LONGER INTO THE AFTN OVER THE E DOWNSTREAM OF LK
MI. ATTENTION THEN TURNS TO TIMING/IMPACT OF SHRTWV NOW MOVING INTO
THE PAC NW. MODELS SHOW THIS DISTURBANCE MOVING EWD TO OVER MN BY
00Z FRI. ALTHOUGH ASSOCIATED SFC LO PRES IS FCST TO MOVE INTO
ONTARIO JUST N OF LK SUP WITH ATTENDANT COLD FNT PROGGED TO REACH
CENTRAL UPR MI BY 00Z...DEEP LARGER SCALE FORCING IS FCST TO HANG TO
THE W THRU THAT TIME. WITH LINGERING MID LVL DRY AIR...ANY
ACCOMPANYING PCPN SHOULD PUSH NO FARTHER THAN WRN LK SUP UNTIL AFT
00Z. OTRW... LOOK FOR ANOTHER DAY OF WELL ABV NORMAL TEMPS UNDER H85
THERMAL RDG UP TO 11C RIGHT AHEAD OF THE FNT. BUT TEMPS OVER THE W
SHOULD FALL IN THE AFTN FOLLOWING THE COLD FROPA WITH H85 TEMPS
PROGGED TO TUMBLE TOWARD 0C AT IWD BY 00Z FRI.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 437 PM EST WED NOV 21 2012
MODEL HAVE COME INTO MUCH BETTER OVERALL AGREEMENT RELATING TO THE
SYSTEM THAT WILL BRING SNOW TO MUCH OF THE AREA THU NIGHT INTO
SAT...WITH MAINLY SMALLER SCALE/TIMING DIFFERENCES THAT ARE NOT OUT
OF THE NORM FOR THE TIME FRAME OF THE EVENT. A GENERAL MODEL
CONSENSUS WAS USED...WITH MOST FORECAST ALIGNMENT WITH THE 12Z/21
NAM/GFS AND TO A SOMEWHAT LESSER DEGREE THE 00Z/21 ECMWF
FOCUSED MAJORITY OF ATTENTION ON THE SYSTEM THU NIGHT INTO SAT GIVEN
HIGHER IMPACTS FROM POST THANKSGIVING TRAVEL/ACTIVITIES.
AT 00Z FRI...MODELS SHOW THE 500MB SHORTWAVE IN THE BEGINNING STAGES
OF BEING CLOSED OFF OVER NW MN WITH A 1000MB SFC LOW OVER CENTRAL
LAKE SUPERIOR...AND A SFC COLD FRONT FROM THE HURON MOUNTAINS TO
IRON OR DICKINSON COUNTY. 850MB TEMPS WILL BE JUST FALLING BELOW 0C
OVER FAR WRN UPPER MI...BUT WILL STILL BY AROUND 6C OVER THE ERN
CWA. THE MID LEVEL LOW WILL CONTINUE TO STRENGTHEN AS IT MOVES TO
THE CENTRAL CWA BY 12Z FRI /AVG LOCATION AMONG PREFERRED
MODELS...THERE WERE MINOR TIMING DIFFERENCES/...WITH HEIGHT FALLS OF
7-10DAM FROM 12 HOURS PREVIOUS. BY 12Z FRI THE BULK OF THE SFC LOW
WILL HAVE SHIFTED NE INTO ONTARIO...BUT PREFER THE NAM/GEM/ECMWF
SOLUTIONS THAT PIN A 998MB SFC LOW OVER NE LAKE SUPERIOR AS OFTEN
HAPPENS DUE TO THE WARM LAKE TEMPS. 850MB TEMPS FALL TO -10C TO -12C
OVER WRN LAKE SUPERIOR BY 12Z FRI...AND WILL WELL BELOW 0C OVER THE
REST OF THE CWA. THE COMBINATION OF THE DEEPENING SFC LOW...COLD AIR
OVER THE WARM LAKE AND SHARP PRESSURE GRADIENT LEAD TO STRONG WINDS.
THE STRONGEST WINDS LOOK TO BE OVER THE KEWEENAW AND NEAR LAKE
SUPERIOR E OF THE HURON MOUNTAINS...ESPECIALLY ALONG THE SHORELINES
OF ALGER AND LUCE COUNTIES. IN THESE AREAS...MODELS SHOW 925MB WINDS
IN EXCESS OF 40KTS...SO GUSTS AS HIGH AS 40KTS SEEM APPROPRIATE FOR
THE FORECAST IN THESE MORE EXPOSED LOCATIONS FROM THE NW WINDS LATE
THU NIGHT AND THROUGH MUCH OF FRI. A SHORT SWATH OF DRY LOW AND MID
LEVEL AIR ROTATES THROUGH THE WRN CWA LATE FRI MORNING...WHICH WILL
DIMINISH SNOWFALL TO SOME EXTENT. MODELS THEN INDICATE ANOTHER
SHORTWAVE PUSHING THROUGH SOMETIME SAT EVENING AS 850MB TEMPS FALL
TO -14C OVER MUCH OF LAKE SUPERIOR...WHICH WILL ACT TO ENHANCE
SNOWFALL RATES. AFTER THIS SHORTWAVE...SNOWFALL SHOULD GENERALLY
SLOWLY DIMINISH IN INTENSITY/COVERAGE UNTIL SFC AND UPPER RIDGING
MOVES IN FROM THE W SAT...REACHING IWD BY 18Z SAT AND THE FAR ERN
CWA AROUND 00Z SUN.
GIVEN HOW QUICKLY TEMPS GET COLD AS THE UPPER LOW IS MOVING
OVER...SNOW TO LIQUID RATIOS WILL JUMP UP PRETTY QUICKLY TO AROUND
18 TO 1 RATIOS. THIS WILL INCREASE SNOWFALL ACCUMULATIONS AND WILL
ALLOW THE SNOW TO BE BLOW AROUND MORE FROM GUSTY WINDS. EXPECT TWO
MAIN BURSTS OF SNOW THAT SHOULD BE ESPECIALLY UNTACTFUL...ONE AS THE
UPPER LOW PUSHES IN WITH LAKE ENHANCEMENT ADDING TO SNOW INTENSITY.
THIS WILL HAPPEN THU NIGHT INTO EARLY FRI MORNING OVER THE WRN
CWA...AND FRI MORNING TO AROUND NOON FRI OVER THE ERN CWA. THE
SECOND BURST LOOKS TO BE WITH THE SECOND SHORTWAVE FRI EVENING TO
EARLY SAT NIGHT WITH ENHANCEMENT OF THE LES. THE FIRST BURST OF SNOW
LOOKS TO BE THE WORST GIVEN THE INCREASED FORCING FROM THE 500MB
LOW...WHICH WILL ALSO BE AT THE WORST TIMES GIVEN MUCH INCREASED
POST THANKSGIVING TRAVEL/ACTIVITY AS FAR A SOCIETAL IMPACTS GO. THIS
IS COMPOUNDED BY THE FACT THAT NO SIGNIFICANT SNOWFALL HAS OCCURRED
IN A WHILE...WHICH LOCAL STUDIES SUGGEST LEADS TO A LARGE INCREASE
IN TRAFFIC ACCIDENTS ONCE SNOW DOES FALL.
AS FAR AS SNOWFALL AMOUNTS GO...HAVE HIGHEST CONFIDENCE IN SNOWFALL
AMOUNTS OF PORTIONS OF ALGER...LUCE AND NRN SCHOOLCRAFT COUNTIES
WHERE MOISTURE WILL LINGER LONGER AND THE FETCH ACROSS LAKE SUPERIOR
WILL BE BETTER AND NW WINDS WILL NOT CHANGE DIRECTIONS MUCH THROUGH
THE EVENT. OVER THESE ERN AREAS...THE NAM SHOWS STORM TOTAL QPF
/WHICH SHOULD BE ALMOST ALL SNOW/ OF JUST UNDER 0.80 INCHES...WHICH
MAY BE A BIT ON THE HIGH SIDE BUT CAN NOT BE RULED OUT.
OVERALL...THINK 6-10 INCHES /WITH SOME POTENTIAL FOR UP TO A FOOT/
TOTAL SNOWFALL SEEMS REASONABLE FOR THE ERN AREAS. LOWEST CONFIDENCE
IS OVER THE NRN HURON MOUNTAINS IN NW MARQUETTE AND NE BARAGA
COUNTIES...AS THIS AREA IS ALWAYS HARD TO FORECAST IN NW WINDS...BUT
WOULD THINK 3-5 INCHES STORM TOTAL SNOW IS REASONABLE. THE HIGHER
TERRAIN OF WRN UPPER MI FROM IWD TO CMX AND COPPER HARBOR SHOULD SEE
4-8 INCHES STORM TOTAL SNOW /HIGHEST OVER PORTION OF NRN HOUGHTON
COUNTY AND WRN ONTONAGON/NRN GOGEBIC COUNTIES/...BUT WITH MORE
UNCERTAINTY THAT THE ERN CWA AND MORE HIGHER POSSIBILITIES OF HIGHER
OR LOWER AMOUNTS. NCENTRAL PARTS OF THE CWA /GENERALLY IN THE
MARQUETTE-NEGAUNEE AREA/ LOOK TO SEE 1-3 INCHES OF SNOW THROUGH THE
ENTIRE PERIOD. SCENTRAL PORTIONS OF THE CWA SHOULD SEE LITTLE TO NO
SNOW.
HEADLINES FOR THIS EVENT ARE SOMEWHAT TRICKY IN THAT TRADITIONAL
SNOWFALL AMOUNT BASED CRITERIA WILL NEED TO BE RELAXED GIVEN A
VARIETY OF PREVIOUSLY DISCUSSED SOCIETAL IMPACTS AND OTHER
CONTRIBUTING FACTORS /SUCH AS GUSTY WINDS/. GIVEN HIGHER CONFIDENCE
OVER THE ERN CWA /ALGER...LUCE AND NRN SCHOOLCRAFT COUNTIES/ DECIDED
TO ISSUE A WINTER STORM WATCH FOR THESE AREAS. ELSEWHERE ALONG THE
LAKE SUPERIOR SHORE...ISSUED AN SPS HIGHLIGHTING POOR TRAVEL
CONDITIONS SINCE IT IS TOO FAR OUT FOR AN ADVISORY.
NEXT SYSTEM OF INTEREST MOVES OVERHEAD ON SAT NIGHT INTO EARLY SUN
AS A CLIPPER SYSTEM PUSHES THROUGH. BEST MOISTURE IS CO-LOCATED WITH
UPPER SUPPORT IN LEFT EXIT REGION OF UPPER JET OVER NRN PORTIONS OF
THE AREA. INCREASED CONSENSUS GUIDANCE TO MID RANGE CHANCE POPS. AT
THIS TIME A COUPLE OF INCHES OF SNOW APPEARS POSSIBLE...MAINLY IN
THE HIGHER TERRAIN OVER THE NRN CWA.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 257 AM EST THU NOV 22 2012
AT KSAW...IFR VIS THAT HAS DEVELOPED UNDER RADIATIONAL COOLING WILL
LIKELY PERSIST THRU THE NIGHT. IFR CIGS MAY ALSO SET IN AT SOME
POINT DURING THE NIGHT. VFR CONDITIONS SHOULD PREVAIL AT KIWD/KCMX
OVERNIGHT AS DOWNSLOPE NATURE OF SSW FLOW SHOULD LIMIT THE POTENTIAL
FOR LOW CLOUDS/FOG. LLWS IS EXPECTED AS SSW WINDS ABOVE RADIATION
INVERSION HAVE INCREASED TO 30KT PER KMQT VAD WIND PROFILE. WINDS
SHOULD CONTINUE TO INCREASE A LITTLE MORE DURING THE NIGHT. DAYTIME
HEATING/MIXING SHOULD END LLWS/DISSIPATE ANY LOW CLOUDS/FOG BY LATE
MORNING. ARRIVAL OF COLD FRONT LATE IN THE DAY WILL LIKELY BRING LOW
MVFR CIGS TO KIWD/KCMX AFTER 20Z. RA/SN CHANGING TO SN WILL DEVELOP
AT KIWD/KCMX IN THE EVENING AND SPREAD TO KSAW LATE EVENING. A
PERIOD OF AT LEAST MDT SNOW/LIFR CONDITIONS IS ANTICIPATED AT KCMX
MID TO LATE EVENING AS SECONDARY COLD FRONT BOOSTS LAKE ENHANCEMENT
UNDER STRONG CAA.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 437 PM EST WED NOV 21 2012
EXPECT S WINDS UP TO 20 KTS THRU THIS EVENING TO INCREASE UP TO 25
KTS LATE TONIGHT AND THU UNDER TIGHTENING PRES GRADIENT AHEAD OF
COLD FRONT ASSOCIATED WITH POWERFUL DISTURBANCE MOVING ACROSS THE
NORTHERN CONUS. ONCE THE COLD FRONT MOVES WEST TO EAST THU AFTERNOON
AND NIGHT...EXPECT A SHARP WIND SHIFT TO THE NW. AS THE PRES
GRADIENT TIGHTENS CONSIDERABLY AND MUCH COLDER AIR MOVES OVER THE
UPPER LAKES...EXPECT A HI END GALE EVENT EXCEPT OVER THE FAR W WITH
THE COLDER AIR ENHANCING THE MIXING OF STRONGER WINDS ALOFT TO THE
LAKE SURFACE. GIVEN THE CONSISTENT FORECAST TIMING AND STRENGTH OF
THIS EVENT...OPTED TO UPGRADE GOING GALE WATCHES TO WARNINGS FOR THE
LATE THU NIGHT INTO FRI NIGHT PERIOD. SOME STORM FORCE WIND GUSTS
WILL ALSO BE POSSIBLE ON FRI...ESPECIALLY OVER THE E HALF OF THE
LAKE. THE APPROACH OF A HI PRES RIDGE LATE FRI NIGHT WILL CAUSE THE
GALES TO DIMINISH W-E THEN. ANOTHER LO PRES TROF WILL IMPACT THE
UPPER GREAT LAKES OVER THE WEEKEND...BUT A WEAKER PRES GRADIENT WILL
LIKELY HOLDS WINDS TO NO HIER THAN 25 KTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER STORM WATCH FROM LATE TONIGHT THROUGH LATE FRIDAY NIGHT
FOR MIZ006-007-085.
LAKE SUPERIOR...
GALE WARNING FROM 1 AM FRIDAY TO 1 AM EST SATURDAY FOR
LSZ264>267.
GALE WARNING FROM 1 AM TO 7 PM EST FRIDAY FOR LSZ243>245-248>251-
263.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...TITUS
AVIATION...ROLFSON
MARINE...KC
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
222 PM CST THU NOV 22 2012
.DISCUSSION...
THERE IS ABOUT A 30 DEGREE DIFFERENCE IN THE TEMPERATURE EARLY
THIS AFTERNOON ACROSS THE CWA FROM WEST TO EAST. THE STRONG COLD
FRONT IS NEAR A RICE LAKE-MENOMINEE LINE AND WILL BE EAST OF OUR
CWA BY 22Z. IN THE WAKE OF THE FRONT...NORTHWEST WINDS OF 20 TO 25
MPH WITH GUSTS WELL INTO THE 30 MPH RANGE ARE COMMON. A BAND OF RAIN
AND SNOW EXISTS AS WELL BEHIND THE FRONT FROM SOUTHWEST MN THROUGH
CENTRAL AREAS OF THE STATE AND INTO THE ARROWHEAD. THIS IS AHEAD
OF AN AXIS OF MID LEVEL FRONTOGENESIS ALONG WITH A SUBSTANTIAL PV
BOOT AIMED AT KDLH. WEB CAMS THIS AFTERNOON HAVE INDICATED A QUICK
COATING OF SNOW AS THE BAND MOVES THROUGH.
OUR LOCAL WRF AND THE HRRR HAVE A PRETTY GOOD HANDLE ON THE
PRECIPITATION PATTERN. THE BAND OF FRONTOGENESIS WILL MOVE THROUGH
THE EASTERN MN...INCLUDING THE TWIN CITIES...IN THE 21Z-24Z TIME
FRAME AND ACROSS WEST CENTRAL WI IN THE 00Z-03Z PERIOD. OUR WRF
AND THE HRRR SUGGEST THE BEST CHANCES FOR PRECIPITATION DURING THE
LATE AFTERNOON AND EARLY EVENING HOURS ARE FROM THE NORTH METRO ON
NORTH AND EAST. THIS IS WHERE LIKELY POPS EXIST FOR A TIME WITH
DIMINISHING POPS TO THE SOUTH. A QUICK HALF INCH OF SNOW IS NOT
OUT OF THE QUESTION.
DURING THE LATE EVENING THROUGH OVERNIGHT HOURS...A SECONDARY
TROUGH WILL ROTATE SOUTHEAST ACROSS THE FA. SOME LIGHT SNOW IS
LIKELY...ESPECIALLY OVER OUR FAR NORTHERN TIER OF COUNTIES WITH
PERHAPS A HALF INCH OF SNOW. THEREFORE...RAISED POPS INTO THE LIKELY
CATEGORY FOR THIS AREA WITH CHANCE POPS FOR A FEW ROWS OF COUNTIES
TO THE SOUTH. ADDED FLURRIES ELSEWHERE OVERNIGHT AND FRIDAY
MORNING WITH THE COLD...MOIST...CYCLONIC FLOW.
DEBATED ON WHAT TO DO WITH THE WIND ADVISORY IN EFFECT THROUGH THE
NIGHT. I WOULD PREFER TO SEE AT LEAST A 10 MB PRESSURE GRADIENT
FROM KMSP TO THE SD BORDER. WE ARE CURRENTLY RUNNING AT 8 MB AND
MOST SOLUTIONS KEEP IT THIS WAY THROUGH THE NIGHT. HOWEVER...
EXAMINATION OF THE VERTICAL PROFILES FROM THE NAM THROUGH BUFKIT
INDICATE WEST CENTRAL THROUGH SOUTH CENTRAL MN AS HAVING PRETTY
GOOD POTENTIAL FOR SEEING 30 MPH SUSTAINED WINDS DURING THE
EVENING HOURS. IN ADDITION...TOP OF THE CHANNEL MOMENTUM TRANSFER
INDICATES THE POTENTIAL FOR EAST CENTRAL MN...INCLUDING THE TWIN
CITIES...TO HAVE GUSTS POTENTIAL NEAR 45 MPH DURING THE EVENING AS
WELL. LOOKING AT THE SREF...SEVERAL NMMB MEMBERS WERE BETWEEN 42
AND 45 KNOTS ADDING CONFIDENCE TO THE NAM SOLUTION. EVEN THE
FAVORITE ARW KF MEMBER WAS AT 42 KNOTS. HENCE...WILL NOT MESS WITH
THE ADVISORY AT THIS TIME WITH PLENTY OF POTENTIAL FOR
VERIFICATION OVER THE NEXT 8 TO 12 HOURS.
IT WILL BE BLUSTERY AND COLD OVER THE AREA TOMORROW AS BRISK
NORTHWEST WINDS CONTINUE. HIGHS WILL ONLY BE IN THE 20S. FACTOR IN
THE WIND AND THE APPARENT TEMPERATURE IS ONLY IN THE SINGLE DIGITS
AND TEENS. THERE SHOULD BE SOME FLURRIES AS WELL OVER EASTERN
AREAS IN THE MORNING.
NOTHING TOO EXCITING DURING THE WEEKEND OR NEXT WEEK. HIGH PRESSURE
WILL PASS BY ON SATURDAY WITH A LITTLE MODERATION IN TEMPERATURE
FOR SUNDAY BEFORE ANOTHER COLD FRONT PUSHES THROUGH ON MONDAY.
THERE ARE SOME DIFFERENCES BETWEEN THE GFS/GEM AND THE ECMWF
REGARDING A LOW PRESSURE SYSTEM PASSING SOUTH OF US MONDAY NIGHT
AND TUESDAY. THE GFS/GEM HAVE IT FARTHER NORTH WITH SNOW INTO FAR
SOUTHERN MN WHILE THE ECMWF HAS HIGH PRESSURE OVER IA WITH THE LOW
WAY SOUTHEAST. COLLABORATION WAS TO LEAVE THE SMALL POPS IN THE
FAR SOUTH PART OF MN DUE TO THE DIFFERENCES.
&&
.AVIATION... /18Z TAF ISSUANCE/
FRONT ALREADY IN THE WESTERN SUBURBS OF THE TWIN CITIES WITH WINDS
SHIFTING TO THE W/WNW AND BEGINNING TO GUST OVER 20 KTS. ABOUT 50
MILES TO THE WEST OF THE FRONTAL PASSAGE...WINDS INCREASE TO ARND
20 KTS...WITH GUSTS ALREADY EXCEEDING OR APPROACHING 30 TO 35 KTS.
IN ADDITION...MVFR/IFR CIGS HAD DEVELOPED BEHIND THIS FRONT ALONG
WITH SOME BR...BUT THESE CIGS HAVE SLOWED A BIT IN THE LAST
HR...AND WITH DIURNAL MIXING AHEAD OF IT...BELIEVE CIGS WILL
EVENTUALLY RISE TO 1.5 OR 2.5K DURING THE MID/LATE AFTN HRS. OUT
WEST IFR/LOW END MVFR CIGS WILL LIKELY CONTINUE BASED ON LITTLE
MIXING ON THE ONSET OF THESE LOWER CIGS. SOME -SHRA...MIXED WITH
IP/SN WAS DEVELOPING ACROSS FAR NE SD...WC MN WHICH IS PROGGED TO
MOVE E/NE ACROSS MAINLY THE NW FA DURING THE AFTN HRS. AS THE
ACTIVITY MOVED ACROSS SD...VSBYS DID NOT DECREASE AS RAPIDLY...SO
WILL CONTINUE WITH HIGH END MVFR VSBYS IN -SN/IP/RA THIS AFTN.
ONCE THE CHG OVER TO -SN OCCURS...THE VSBYS COULD
DROP...ESPECIALLY AT AXN/STC OVERNIGHT AS BETTER FORCING AND
DEEPER MOISTURE RESIDES. WINDS WILL BE THE STRONGEST DURING THE
EVENING/OVERNIGHT HRS...THEN SLOWLY DECREASING FRIDAY
MORNING...BUT REMAINING GUSTY.
KMSP...
MVFR CIGS IN THE WESTERN SUBURBS OF THE TWIN CITIES IS THE MAIN
CONCERN IN THE FIRST 3-6 HRS...DECIDED TO GO WITH MORE MIXING THIS
AFTN WITH CIGS BECOMING 2.0K BY 20Z. SOME CLDS BLW 1.5K WILL BE
NOTED...BUT IT SHOULD NOT BE A CIG THIS AFTN. WILL CONTINUE TO
MONITOR CIGS IN THE WEST AND SEE IF THESE CONTINUE TO THEIR STEADY
PACE TOWARD MSP. SOME -SHRA WILL BE POSSIBLE THIS AFTN...BUT MORE
LIKELY AFT 22Z...THRU 01Z. DEEPER MOISTURE ALONG WITH BETTER
FORCING DEVELOPS OVERNIGHT WHICH MAY MEAN SCATTERED -SN...WITH
MVFR VSBYS. BUT CONFIDENCE IS TOO LOW TO HAVE ANYTHING OTHER THAN
FLURRIES. CIGS WILL LIKELY HOLD IN THE MVFR RANGE OVERNIGHT...WITH
CIGS SLOWLY RISING AND BECOMING VFR FRIDAY AFTN.
/OUTLOOK FOR KMSP/
SAT...VFR. WINDS S AT 5-10KTS.
SUN...VFR. WINDS WNW AT 5-10KTS.
MON...MAINLY VFR...POSSIBLE MVFR CIGS LATE WITH -SN.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WIND ADVISORY UNTIL 6 AM CST FRIDAY FOR ANOKA-BLUE EARTH-BROWN-
CARVER-CHIPPEWA-DAKOTA-DOUGLAS-FARIBAULT-FREEBORN-GOODHUE-
HENNEPIN-KANDIYOHI-LAC QUI PARLE-LE SUEUR-MARTIN-MCLEOD-
MEEKER-NICOLLET-POPE-RAMSEY-REDWOOD-RENVILLE-RICE-SCOTT-
SHERBURNE-SIBLEY-STEARNS-STEELE-STEVENS-SWIFT-TODD-WASECA-
WASHINGTON-WATONWAN-WRIGHT-YELLOW MEDICINE.
WI...NONE.
&&
$$
RAH/JLT
AREA FORECAST DISCUSSION
NWS BILLINGS MT
922 AM MST THU NOV 22 2012
.SHORT TERM...VALID FOR TDY AND FRI...
CANADIAN COLD FRONT AND ASSOCIATED PRESSURE RISES SURGING MUCH
FURTHER WEST THAN PREVIOUSLY THOUGHT. COLD AIR HAS PUSHED THROUGH
JUDITH GAP WHERE TEMP MADE AN 11 DEGREE DROP FROM 31F TO 20F LAST
HOUR. STRONG COLD ADVECTION FURTHER EAST IS NOT QUITE TO MILES
CITY AND BAKER BUT WILL BE BEFORE MIDDAY. WITH TEMPS LARGELY IN
THE TEENS UPSTREAM...EXPECT A FAIRLY DRAMATIC TEMPERATURE DROP
ESPECIALLY IN OUR EAST. PER LOCATION OF UPSTREAM PRESSURE
RISES...THINK THIS FROPA WILL HAVE SOME IMPACT AT BILLINGS AS
WELL. FOR BILLINGS...EXPECT A SHIFT TO NORTH THEN EVENTUALLY
NORTHEAST WINDS THIS AFTERNOON...AND AN ASSOCIATED TEMPERATURE
DROP TO MAYBE THE LOW 30S/UPPER 20S AFTER A MIDDAY HIGH IN THE
LOW 40S. AS FOR PCPN...TROWAL WRAPPING SOUTHWARD THROUGH NORTHERN
MT WILL BRING SOME LIGHT SNOW SHOWERS TO OUR EASTERN PARTS...WITH
STRONGEST ASCENT PER THE RAP EXPECTED TO BE FROM ABOUT 18-23Z.
GIVEN MOISTENING OF DENDRITIC LAYER WHICH WILL FALL TO THE
SFC...COULD BE A DUSTING IN PLACES MAINLY EAST OF HYSHAM AND LAME
DEER. AREAS FROM FORSYTH TO BAKER HAVE ALSO EXPERIENCED SOME
STRATUS THIS MORNING PER ADVECTION FROM THE NW. WEB CAMS HAVE
SHOWN SOME VSBY REDUCTIONS OVER THE HILLS OUT THAT WAY.
NW WINDS WILL BE QUITE GUSTY THIS AFTERNOON ESPECIALLY ACROSS OUR
EAST...WITH CORE OF STRONGEST BOUNDARY LAYER WINDS PUSHING INTO
THE DAKOTAS. LOOKS LIKE WIDESPREAD 35-45 MPH GUSTS EAST OF
BILLINGS. CURRENT FORECAST HAS COVERED WELL.
ANY -SHSN ACTIVITY SHOULD BE OVER BY LATE AFTERNOON...LEADING TO A
DRY NIGHT TONIGHT WITH MUCH COLDER TEMPS/LIGHTER WINDS AS SFC
RIDGE BUILDS IN. WILL HAVE TO SEE HOW FAR WEST COLD ADVECTION
PUSHES DURING THE DAY AS THIS WILL IMPACT LOWS TONIGHT AND
LOCATION OF LEE SIDE TROF WHEN IT DEVELOPS.
JKL
.LONG TERM...VALID FOR SAT...SUN...MON...TUE...WED...
EXTENDED MODELS IN OVERALL AGREEMENT WITH LARGE-SCALE FEATURES
BUT DIFFER IN SOME PARTICULAR DETAILS. A STRONG COLD FRONT WILL
SWEEP ACROSS THE FORECAST AREA LATE SATURDAY AFTERNOON INTO
SATURDAY EVENING. AHEAD OF THE FRONT...EXPECT GUSTY SOUTHWEST TO
WEST WINDS ALONG WITH DOWNSLOPE WARMING...ALTHOUGH TEMPERATURES
WILL NOT WARM TOO MUCH. HIGH TEMPERATURES WILL BE TRICKY DEPENDING
ON TIMING OF THE FRONT BUT MOST PLACES SHOULD RISE INTO THE UPPER
30S TO LOWER 40S.
THE FRONT WILL BRING RAIN AND SNOW SHOWERS WITH THE PRECIP
CHANGING TO ALL SNOW BY LATE SATURDAY NIGHT. AN EASTERLY UPSLOPE
FLOW AND FRONTOGENESIS BAND DEVELOP LATE SATURDAY NIGHT THROUGH
SUNDAY ACROSS MOST OF THE FORECAST AREA BUT ESPECIALLY ALONG THE
EASTERN SLOPES OF THE BEARTOOTH/ABSAROKA MOUNTAINS TO THE BIG
HORNS. THE AREA SHOULD SEE WIDESPREAD SNOW LATE SATURDAY NIGHT
THROUGH THE ENTIRE DAY SUNDAY BEFORE TAPERING OFF BY MONDAY
MORNING. AT THIS TIME...ADVISORY TYPE ACCUMULATIONS LOOK LIKELY
FOR MANY LOCATIONS. TEMPERATURES ARE NOT VERY COLD WITH THIS
SYSTEM RESULTING IN SNOW RATIOS AROUND 10:1 FOR MOST OF THE EVENT
WITH SOME HIGHER RATIOS SUNDAY NIGHT.
THE SYSTEM LOOKS TO BE DIFFERENT FROM WHAT OUR AREA USUALLY SEES
WITH A COLD FRONT AND SNOW IN THAT TEMPERATURES ARE NOT EXPECTED
TO GET VERY COLD LIKE USUALLY IS THE CASE WITH A FRONT DROPPING
OUT OF CANADA THIS TIME OF YEAR. TEMPERATURES MONDAY ARE STILL
EXPECTED TO REBOUND INTO THE UPPER 20S TO LOWER 30S AFTER MORNING
LOWS IN THE TEENS. UNSETTLED NORTHWEST FLOW ALOFT LOOKS TO BE OVER
THE FORECAST AREA TUESDAY INTO WEDNESDAY WITH A POSSIBLE RIDGE AND
WARMER TEMPERATURES BUT LATE NEXT WEEK. HOOLEY
&&
.AVIATION...
REINFORCING COLD FRONT LOCATED FROM LEWISTOWN TO SOUTH OF MILES
CITY AND BAKER WILL CONTINUE TO SLIDE SOUTH TODAY. FRONT WILL
LIKELY BACK TO A POSITION JUST EAST OF LIVINGSTON AND ALONG THE
BEARTOOTH FRONT BEFORE BECOMING STATIONARY THIS EVENING. LOW LEVEL
MOISTURE WILL BRING WIDESPREAD MVFR TO OCCASIONAL IFR CEILINGS
BEHIND THIS FRONT...ALONG WITH SCATTERED SNOW SHOWERS EAST OF A
ROUNDUP TO HARDIN LINE. TO THE WEST OF THE FRONT WEST TO NORTHWEST
WINDS WILL BE GUST TO AROUND 30 KTS AT TIMES...WHILE A NORTH TO
NORTHEAST WIND WILL FILL IN BEHIND THE FRONT.
FOR KMLS TAF LOCATION...IFR VISIBILITY FOG HAS DEVELOPED BEHIND
THE RECENT COLD FRONTAL PASSAGE. EXPECT THIS FOG TO LIFT AS
SCATTERED SNOW SHOWERS MOVE INTO THE AREA BY MID DAY. HOWEVER AN
MVFR TO IFR STRATUS CEILING WILL PERSIST...LIKELY THROUGH LATE
TONIGHT.
FOR KBIL TAF LOCATION...COLD FRONT WAS 50NM TO THE NORTH OF THE
AIRPORT AT 16Z. WEST WINDS GUSTING TO 30 KTS WILL PERSIST UNTIL
FRONTAL PASSAGE...AROUND 19Z. ONCE THE FRONT MOVES THROUGH EXPECT
WINDS TO TURN NORTHEASTERLY AND MVFR CEILING TO DEVELOP. MVFR
CEILINGS WILL PERSIST THROUGH LATE TONIGHT. CHAMBERS
&&
.PRELIMINARY POINT TEMP/POPS...
TDY FRI SAT SUN MON TUE WED
-------------------------------------------------------
BIL 041 022/051 037/051 031/034 020/031 016/035 021/040
0/N 00/B 04/W 67/S 73/J 12/J 32/W
LVM 038 022/050 038/046 028/033 018/031 014/033 022/039
0/N 00/N 06/W 78/S 74/J 12/J 32/W
HDN 043 017/051 030/052 030/036 020/032 014/035 020/041
1/N 00/B 04/W 67/S 73/J 11/B 22/W
MLS 032 011/040 028/049 028/030 017/028 014/031 020/036
3/J 00/B 02/W 46/S 42/J 11/B 21/B
4BQ 038 011/044 029/052 029/035 018/029 014/033 020/039
3/J 00/U 02/W 67/S 63/J 11/B 21/B
BHK 032 007/036 026/047 025/027 015/026 013/029 018/036
3/J 00/U 00/B 36/S 41/E 11/B 11/B
SHR 038 015/049 028/052 027/033 018/029 011/032 018/041
2/J 00/U 03/W 67/S 73/J 11/B 22/W
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
238 PM CST THU NOV 22 2012
.DISCUSSION...
THE ARCTIC FRONT APPEARS TO BE ENTERING NWRN SD THIS AFTN. THE
LATEST NAM AND RAP SOLNS SHOW THIS FRONT DROPPING THRU NCNTL NEB
THIS EVENING WITH WINDS ALOFT INCREASING TO 65KT AT 700MB...50KT
AT 850MB AND 25 TO 30KT AT 500M AGL. SO SFC WINDS COULD RUN 25 TO
30 MPH ALONG THE FRONT AND POTENTIAL GUSTS TO 45 MPH. THUS THE
WIND ADVISORY WILL BE EXTENDED ACROSS PARTS OF NCNTL NEB TONIGHT
IN ANTICIPATION OF THIS FRONTAL PASSAGE.
ARCTIC HIGH PRESSURE SLIDES THROUGH THE MISSOURI BASIN FRIDAY AND
INTO THE MID SOUTH BY SATURDAY MORNING. WITH THE ARCTIC HIGH
BUILDING THROUGH THE MISSOURI BASIN...THE COLD CORE NEVER REACHES
FAR WESTERN NEB SO A QUICK TEMPERATURE REBOUND CAN OCCUR SATURDAY
AS NEW LOW PRESSURE TRACKS THROUGH SRN SASKATCHEWAN AND MANITOBA
TURNING TO THE WEST ACROSS THE FCST AREA.
THIS LOW THEN DROPS ANOTHER ARCTIC FRONT INTO SOUTH DAKOTA SUNDAY
WITH NW FLOW ALOFT MAINTAINING A BAROCLINIC ZONE AND WEAK MID
LEVEL FRONTOGENESIS DEVELOPING. THE SFC FRONT IS FCST TO DROP
THROUGH NRN NEB SUNDAY AFTERNOON AND THE MODELS SUGGEST
SUFFICIENT LOW LEVEL MOISTURE FOR A CHANCE OF LIGHT RAIN OR SNOW
SUNDAY AFTERNOON CHANGING TO SNOW SUNDAY NIGHT AND ENDING MONDAY
MORNING. LIGHT ACCUMULATIONS WOULD DEVELOP GIVEN THE FLEETING
NATURE OF THE MID LEVEL FRONT...THE OPEN WAVE AT 700MB SHOWN BY
ALL MODELS AND 250 MB JET MAX MOVING THROUGH SRN NEB.
WEAK ARCTIC HIGH PRESSURE MOVES QUICKLY THROUGH THE FCST AREA TUESDAY
FOLLOWED BY ANOTHER LOW PRESSURE SYSTEM TRACKING ALONG THE
CANADIAN BORDER WEDNESDAY. THIS SYSTEM WILL PULL ANOTHER FAST
MOVING ARCTIC HIGH PRESSURE SYSTEM INTO THE FCST AREA FOR NEXT THURSDAY.
SAVE FOR ISOLATED FLURRIES WITH THE ARCTIC FRONT TONIGHT AND LIGHT
SNOW POSSIBLE LATE SUNDAY AND MONDAY MORNING...THE FORECAST IS
DRY. TEMPERATURES RANGE FROM 30S AND 40S NORTHEAST TO 40S AND 50S
SOUTHWEST.
&&
.AVIATION...
WINDS WILL CONTINUE TO BE THE PRIMARY AVIATION CONCERN THROUGH
FRIDAY. STRONG NORTHWEST TO NORTHERLY WINDS WILL CONTINUE THROUGH
THEN AFTERNOON AS A TIGHT PRESSURE GRADIENT AND GOOD MIXING OCCURS
ACROSS THE AREA. WINDS WILL DIMINISH FOR A PERIOD THIS EVENING...
THEN EXPECT ANOTHER INCREASE IN WINDS LATER IN THE EVENING AND
INTO THE OVERNIGHT PERIODS /ROUGHLY 03Z TO 08Z/ AS A FRONT MOVES
THROUGH THE REGION FROM NORTH TO SOUTH. THE STRONGEST WINDS ARE
EXPECTED OVER NORTH CENTRAL NEBRASKA...INCLUDING THE KVTN TAF SITE.
WINDS IN THESE AREAS COULD AGAIN GUST UP TO 45 MPH. WINDS WILL
DIMINISH BY MORNING WITH BENIGN AVIATION WEATHER CONDITIONS FOR
FRIDAY.
&&
.FIRE WEATHER...
OBSERVATIONS ACROSS WESTERN NEBRASKA HAVE GOTTEN NEAR RED FLAG
CRITERIA THIS AFTERNOON AS WINDS GUSTED BETWEEN 35 AND 45
MPH...WHILE DEW POINTS DROPPING INTO THE SINGLE DIGITS AND LOW TEENS
LOWERED RELATIVE HUMIDITY INTO THE UPPER TEENS AND LOW 20S.
HOWEVER...COLDER AIR WAS IN PLACE...WITH TEMPERATURES ONLY IN THE
MID AND UPPER 40S. ALTHOUGH CONDITIONS ARE CLOSE...AND MAY EVEN HIT
CRITERIA IN LOCALIZED SPOTS FOR A FEW HOURS...THESE LOWER
TEMPERATURES WILL KEEP FROM ISSUING A SHORT FUSED RED FLAG WARNING
FOR THE REMAINDER OF THE AFTERNOON. THAT BEING SAID...WITH THE
STRONG WINDS...ANY FIRES WILL STILL HAVE THE POTENTIAL TO SPREAD
RAPIDLY THIS AFTERNOON.
BEYOND TODAY...SATURDAY COULD SEE ELEVATED FIRE WEATHER CONDITIONS
WITH RELATIVE HUMIDITY DROPPING INTO THE UPPER TEENS AND
20S...HOWEVER WINDS ARE ONLY FORECAST AT 15 TO 20 MPH AT THE PEAK.
OTHERWISE THE REMAINDER OF THE NEXT 7 DAYS SHOULD BE QUIET FOR FIRE
CONCERNS.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...WIND ADVISORY UNTIL 6 PM CST
/5 PM MST/ THIS EVENING FOR
NEZ004-022>024-035>037-056>059-069>071-094.
WIND ADVISORY UNTIL 4 AM CST FRIDAY FOR NEZ005>010-025>029-038.
&&
$$
SHORT TERM/EXTENDED...CDC
AVIATION...BROOKS
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
433 AM EST THU NOV 22 2012
.SYNOPSIS...
HIGH PRESSURE WILL BRING ANOTHER MILD AND SUNNY DAY TO CENTRAL NEW
YORK AND NORTHEAST PENNSYLVANIA. A COLD FRONT WILL PASS THE REGION
LATE FRIDAY AFTERNOON AND EVENING WITH SHOWERS. COLD AIR BEHIND
THIS FRONT WILL ALLOW LAKE EFFECT SNOWS TO DEVELOP OVER PORTIONS OF
CENTRAL NEW YORK LATE FRIDAY NIGHT...WHICH WILL PERSIST INTO
SATURDAY NIGHT.
&&
.NEAR TERM /THROUGH TONIGHT/...
SFC HI PRES RDG XTNDG FROM NEW ENGLAND INTO THE MID ATLC STATES
WILL BRING ANOTHER VERY NICE DAY TO THE FCST AREA...WITH MOSTLY
SUNNY SKIES AND TEMPS WELL ABV NORMAL. GIVEN FCST 925 TEMPS OF +8
IT LOOKS LIKE WE`LL SEE MAXES FLIRTING WITH 60 IF NOT THE LOWER 60S
ACRS THE CNTRL SRN TIER AND FINGER LAKES...M/U 50S ELSEWHERE.
FAIR WX CONTNIUE TNGT WITH SRLY FLOW INCRSNG.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
WE`LL SEE SOME SUNSHINE AHEAD OF THE FNT ON FRI AND IT APPEARS
WE`LL HAVE MAXES WELL INTO THE 50S ONCE AGAIN. CDFNT WILL PASS
LATE FRI AFTN/FRI EVNG WITH A BAND OF -SHRA. COLDER AIR WORKS IN
BEHIND THE FNT FRI NGT INTO SAT. ATTM IT APPEARS THAT FLOW WILL
REMAIN WSW TIL ARND 06Z WITH FLOW BCMG MORE NWLY BY 12Z SAT. THE
NW FLOW PERSISTS INTO SAT NGT. CYCLONIC FLOW ALOFT...GOOD LOW LVL
INSTAB...DENDRITIC SNOW GROWTH AND FAIRLY HI INVERSION LVL SHOWN
IN IN THE PROFILES...WITH SOME HINT OF PSBL HURON BAY CONNECTION
TO ONTARIO ACTIVITY ON SAT. HOWEVER...SOME SUGGESTION THAT THE
SYNOPTIC AIR MASS MAY BE ON THE DRY SIDE (EURO SHOWS TD`S DROPPING
INTO THE L/M TEENS DURING THIS TIME FRAME). IN ANY EVENT...POTNL
APPEARS TO BE THERE FOR ACCUMULATIONS....PRBLY IN THE ADVISORY
RNG...SPCLY ACRS THE FAVORED TRRN IN 300-320 FLOW SAT INTO SAT NGT.
WILL CONTINUE TO MENTION IN THE HWO.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
345 AM UPDATE...
FORECAST ONLY ADJUSTED SLIGHTLY AS NEEDED FOR COLLABORATION
PURPOSES AND TO ACCOUNT FOR LATEST MODEL TRENDS. THE GENERAL IDEA
REMAINS THE SAME.
850MB RIDGE NEVER REALLY REACHES THE AREA...IT ACTUALLY FLATTENS
TO OBLIVION IN RESPONSE TO PASSING WAVE ON SUNDAY. WAVE EVENTUALLY
YIELDS WARM AIR ADVECTION ALOFT...BUT 850MB TEMPERATURES REMAIN
COLD ENOUGH FOR AT LEAST A MARGINAL CONTINUED LAKE RESPONSE. WARM
FRONT MAY STRUGGLE TO FILL THE DRY LAYER BETWEEN HIGH LEVEL
MOISTURE ASSOCIATED WITH WARM FRONT ALOFT...AND LAKE MOISTURE IN
THE LOWER LEVELS. REGARDLESS THOUGH...LAKE MOISTURE BY ITSELF MAY
BE ENOUGH FOR AT LEAST SCATTERED SNOW SHOWERS TO CONTINUE INTO A
WAYS INTO SUNDAY FOR CENTRAL NY WHILE SHIFTING NORTHWARD /BACKING
WIND/.
MODELS CONTINUE THEIR CONFUSION FOR HOW TO HANDLE LOW PRESSURE
SYSTEM MON NIGHT THROUGH TUE NIGHT PERIOD. ECMWF KEEPS US COLDER
YET IS SO FAR SOUTH WITH TRACK OF LOW /WHICH IS ALSO
WEAKER/...THAT DEPICTED PRECIPITATION SHIELD DOES NOT EVEN MAKE IT
INTO OUR AREA DUE TO STRENGTH OF SURFACE HIGH OVER EASTERN CANADA.
MEANWHILE GFS IS BETTER PHASED AND AMPLIFIED...AND THUS DEVELOPS
STRONGER SURFACE LOW THAT TRACKS UP OHIO VALLEY AND THROUGH THE
REGION. SOME WARMER AIR GETS INVOLVED IN THE GFS SOLUTION...WHICH
MAKES PRECIPITATION TYPE COMPLICATED YET EVENTUALLY TRANSITIONING
TO ALL SNOW SHOWERS IN THE WAKE OF THE POTENTIAL SYSTEM. WITH MUCH
UNCERTAINTY...KEEPING POPS ONLY IN CHANCE RANGE SEEMS BEST AT THIS
TIME.
&&
.AVIATION /09Z THURSDAY THROUGH MONDAY/...
06Z UPDATE...
VFR FOR ENTIRE TAF PERIOD...EXCEPT FOR QUESTION OF EARLY MORNING
VALLEY FOG DEVELOPMENT IN KELM...AND SOME MVFR VIS FOR KITH. GREAT
RADIATIONAL COOLING SET UP AND SHARP INVERSION...SUPPORTIVE OF
KELM VALLEY FOG...IS COMPETING WITH VERY ATMOSPHERE /AFTER YET
ANOTHER DAYTIME OF NO PRECIP AND LOW HUMIDITY LEVELS/. RAP MODEL
SOUNDING OVERALL SEEMS TILTED IN FAVOR OF THE DRY AIR MASS...WITH THE
MORE DEGRADED CONDITIONS STAYING TO OUR NORTH AND WEST /AS IS
ALREADY OCCURRING FOR MANY TERMINALS ON THE ONTARIO PENINSULA/...WHERE
HIGHER DEWPOINTS WERE ABLE TO ADVECT IN EARLIER. I HAVE TO RESPECT
THE STILL FAIR SET UP FOR KELM...AND INCLUDED TEMPO IFR 11Z-13Z...BUT
OTHERWISE HELD THE LINE AT MVFR VIS EARLY THIS MORNING. LIGHT
EASTERLY FLOW WILL ALSO YIELD SOME MVFR VIS FOR A TIME EARLY THIS
MORNING. FOR KRME...WILL HAVE TO WATCH FOR POSSIBLE MVFR LIGHT FOG
BUT NOT IN TAF BECAUSE MOST LIKELY SCENARIO IS VFR.
OUTLOOK...
FRI...MVFR POSSIBLE ALONG AND BEHIND SHOWERY COLD FRONT AFTN/EVE.
FRI NGT...MVFR CIGS. LATE IFR VIS POSS KSYR-KRME FROM LAKE -SHSN.
SAT...MVRF/BRIEF IFR FROM LAKE -SHSN...MAINLY CNY TERMINALS.
SUN...RESTRICTIONS PSBL IN SCT SHRA/SHSN.
MON...MAINLY VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
LONG TERM...MDP/PVN
AVIATION...MDP
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
410 AM EST THU NOV 22 2012
.SYNOPSIS...
WARM ABOVE AVERAGE TEMPERATURES WILL PREVAIL ACROSS THE REGION ON
THANKSGIVING DAY WITH MANY LOCATIONS EASILY WARMING INTO THE
MIDDLE TO UPPER 50S FOR DAYTIME HIGHS. ABOVE NORMAL TEMPERATURES
WILL QUICKLY COME TO AN END BY FRIDAY AS A STRONG COLD FRONT
SWINGS THROUGH THE REGION. COLD AIR WILL RAPIDLY OVERSPREAD THE
REGION FRIDAY NIGHT AND SATURDAY WITH REDEVELOPING LAKE EFFECT
SNOWS EXPECTED OVER THE UPCOMING WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
1030 PM UPDATE...CURRENT FORECAST REMAINS IN GOOD SHAPE, JUST
LOWERED OVERNIGHT LOWS BY 2-4 DEGREES AS WEAK BOUNDARY LAYER FLOW
WILL PERSIST UNTIL DAYBREAK EVEN ALONG THE LAKE PLAIN. WITH DEW
POINTS CONTINUING TO FALL IN TANDEM WITH SFC TEMPS, DENSE FOG
FORMATION IS NOT EXPECTED.
530 PM UPDATE...CLEAR SKIES AND LIGHT WINDS HAVE ALLOWED TEMPS TO
FALL QUICKLY LATE THIS AFTERNOON. AT PENN YAN AND ELMIRA TEMPS
FELL 10 AND 13 DEGREES RESPECTIVELY DURING THE PAST HOUR. ADJUSTED
TEMP GRIDS TO REFLECT THIS OTHERWISE FORECAST IN GOOD SHAPE WITH
NO OTHER CHANGES.
PREVIOUS DISC...
VISIBLE SATELLITE IMAGERY SHOWING MOSTLY CLEAR SKIES ACROSS THE
REGION THIS AFTERNOON AS SFC RIDGING ASSOCIATED WITH CANADIAN
MARITIMES HIGH PRESSURE CONTINUES TO EXTEND SOUTHWEST OVER OUR
AREA. WITH ABUNDANT SUNSHINE PREVAILING OVERHEAD...TEMPS HAVE WARMED
INTO THE LOWER 50S ACROSS MUCH OF THE AREA WHICH IS ANYWHERE
BETWEEN 5-10 DEGREES ABOVE NORMAL. WITH A DRY AIRMASS IN
PLACE...TEMPS WILL FALL OFF QUICKLY THIS EVENING WITH OVERNIGHT
LOWS EXPECTED TO REACH THE LOWER TO MIDDLE 30S. THE ONLY CONCERN
WITH THE GOING FCST OVERNIGHT WILL BE POSSIBLE FOG FORMATION
TOWARDS MORNING. UPSTREAM OBSERVATIONS THIS MORNING SHOWED AN
EXPANSIVE AREA OF FOG ACROSS THE UPPER MIDWEST WHERE VISIBILITIES
WERE NEAR ZERO ACROSS THE GREATER CHICAGO AREA FOR HRS. THIS MOIST
LOW-LEVEL AIRMASS WILL ADVANCE EAST OVERNIGHT WHERE IT WILL
ENCOUNTER MORE AND MORE DRY AIR WITH FURTHER EASTWARD PROGRESS.
FOR NOW...STATISTICAL GUIDANCE MAKING NO SUGGESTION OF ANY FOG
FORMATION ACROSS OUR AREA HOWEVER EVENING SHIFT WILL HAVE TO
MONITOR TRENDS ACCORDINGLY.
UNSEASONABLY WARM TEMPS TO CONTINUE RIGHT THROUGH THANKSGIVING DAY
WHERE 925-MB THERMAL RIDGING CHARACTERIZED BY TEMPS APPROACHING 9C
WILL SUPPORT AFTERNOON HIGH TEMPS REACHING THE MIDDLE TO UPPER 50S
ACROSS MANY AREAS. THAT SAID...HAVE ELECTED TO INCREASE TEMPS A
FEW DEGREES WITH UPPER 50S NOW BEING FORECAST ACROSS THE LAKE
PLAIN WHERE DOWNSLOPE COMPRESSIONAL WARMING MAY ALLOW TEMPS TO
APPROACH 60. FROM A CLIMATOLOGICAL STANDPOINT...IF SYR WERE TO
HIT 60 ON THANKSGIVING DAY...IT WILL BE THE FIRST TIME SINCE 2004
WHEN THE MERCURY CLIMBED TO A BALMY 63 DEGREES. DRY CONDITIONS TO
CONTINUE RIGHT THROUGH THANKSGIVING NIGHT WITH OVERNIGHT LOWS
EXPECTED TO FALL INTO THE MIDDLE TO UPPER 30S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/...
BIG CHANGES ON THE WAY BEGINNING FRI AS A WELL ADVERTISED COLD
FRONT SWINGS THROUGH THE AREA. PRECIP ALONG AND AHEAD OF THE FRONT
WILL BEGIN WORKING THROUGH THE WESTERN ZONES DURING THE LATE
MORNING BEFORE CLEARING THE ENTIRE CWA BY EARLY EVENING. WITH THE
FRONT MOVING THROUGH RAPIDLY...EXPECT PRECIP TOTALS TO GENERALLY
RANGE BELOW TWO TENTHS OF AN INCH. FOR AREAS MAINLY ALONG AND
WEST OF I-81...TEMPS WILL FALL RAPIDLY THROUGH THE MID/LATE
AFTERNOON AS STRONG COLD AIR ADVECTION OVERSPREADS THE REGION IN
THE FRONT/S WAKE.
BIG STORY HOWEVER WILL BE THE RAPID COOL DOWN EXPECTED FOLLOWING
FROPA AND THE REDEVELOPMENT OF LAKE EFFECT SNOW BEGINNING EARLY SAT
MORNING. INITIAL WIND DIRECTION FOLLOWING FROPA WILL FOLLOW A
WESTERLY TRAJECTORY WHICH WILL FAVOR THE SOUTHERN TUG HILL THROUGH
ROUGHLY 12Z ON SAT. FOLLOWING THIS...BOTH NAM AND GFS FCST MODELS
SHOW A SFC TROUGH DROPPING SOUTH IN CYCLONIC FLOW WHICH WILL ALLOW
WINDS TO SHIFT AROUND TO THE NORTHWEST THROUGH THE MORNING. AS
THIS OCCURS...850-MB TEMPS WILL CONTINUE TO COOL WITH VALUES
REACHING NEAR -13C BY 00Z SUN. INSPECTION OF SEVERAL GFS AND NAM
BUFKIT SOUNDINGS REVEALS AN INCREASINGLY FAVORABLE ENVIRONMENT FOR
LAKE EFFECT SNOWS THROUGH THE DAY ON SAT WITH GOOD SATURATION
THROUGH THE FAVORABLE DENDRITIC SNOW GROWTH REGION. THAT
SAID...HAVE DRAWN HIGHEST POPS FROM SOUTHERN ONEIDA COUNTY WEST
THROUGH THE CENTRAL FINGER LAKES TO INCLUDE THE
ITHACA AND SYRACUSE METRO AREAS. FROM THIS VANTAGE
POINT...SEVERAL INCHES OF FRESH LAKE EFFECT SNOWFALL WILL BE
POSSIBLE AS TEMPS STRUGGLE TO REACH THE MID 30S FOR DAYTIME HIGHS.
FOR NOW...IT LOOKS LIKE LAKE SNOWS WILL CONTINUE RIGHT THROUGH SAT
NGT WHICH WILL OBVIOUSLY JUST ADD TO SNOW TOTALS. WOULD NOT BE
SURPRISED IF ADVISORIES EVENTUALLY GET POSTED HOWEVER ITS MUCH TO
EARLY FOR THIS NOW. IN ANY EVENT...WILL HIGHLIGHT SNOW ACCUMULATION
POTENTIAL IN THE HWO TO INCREASE AWARENESS FOR HOLIDAY WEEKEND
TRAVELERS.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
345 AM UPDATE...
FORECAST ONLY ADJUSTED SLIGHTLY AS NEEDED FOR COLLABORATION
PURPOSES AND TO ACCOUNT FOR LATEST MODEL TRENDS. THE GENERAL IDEA
REMAINS THE SAME.
850MB RIDGE NEVER REALLY REACHES THE AREA...IT ACTUALLY FLATTENS
TO OBLIVION IN RESPONSE TO PASSING WAVE ON SUNDAY. WAVE EVENTUALLY
YIELDS WARM AIR ADVECTION ALOFT...BUT 850MB TEMPERATURES REMAIN
COLD ENOUGH FOR AT LEAST A MARGINAL CONTINUED LAKE RESPONSE. WARM
FRONT MAY STRUGGLE TO FILL THE DRY LAYER BETWEEN HIGH LEVEL
MOISTURE ASSOCIATED WITH WARM FRONT ALOFT...AND LAKE MOISTURE IN
THE LOWER LEVELS. REGARDLESS THOUGH...LAKE MOISTURE BY ITSELF MAY
BE ENOUGH FOR AT LEAST SCATTERED SNOW SHOWERS TO CONTINUE INTO A
WAYS INTO SUNDAY FOR CENTRAL NY WHILE SHIFTING NORTHWARD /BACKING
WIND/.
MODELS CONTINUE THEIR CONFUSION FOR HOW TO HANDLE LOW PRESSURE
SYSTEM MON NIGHT THROUGH TUE NIGHT PERIOD. ECMWF KEEPS US COLDER
YET IS SO FAR SOUTH WITH TRACK OF LOW /WHICH IS ALSO
WEAKER/...THAT DEPICTED PRECIPITATION SHIELD DOES NOT EVEN MAKE IT
INTO OUR AREA DUE TO STRENGTH OF SURFACE HIGH OVER EASTERN CANADA.
MEANWHILE GFS IS BETTER PHASED AND AMPLIFIED...AND THUS DEVELOPS
STRONGER SURFACE LOW THAT TRACKS UP OHIO VALLEY AND THROUGH THE
REGION. SOME WARMER AIR GETS INVOLVED IN THE GFS SOLUTION...WHICH
MAKES PRECIPITATION TYPE COMPLICATED YET EVENTUALLY TRANSITIONING
TO ALL SNOW SHOWERS IN THE WAKE OF THE POTENTIAL SYSTEM. WITH MUCH
UNCERTAINTY...KEEPING POPS ONLY IN CHANCE RANGE SEEMS BEST AT THIS
TIME.
&&
.AVIATION /09Z THURSDAY THROUGH MONDAY/...
06Z UPDATE...
VFR FOR ENTIRE TAF PERIOD...EXCEPT FOR QUESTION OF EARLY MORNING
VALLEY FOG DEVELOPMENT IN KELM...AND SOME MVFR VIS FOR KITH. GREAT
RADIATIONAL COOLING SET UP AND SHARP INVERSION...SUPPORTIVE OF
KELM VALLEY FOG...IS COMPETING WITH VERY ATMOSPHERE /AFTER YET
ANOTHER DAYTIME OF NO PRECIP AND LOW HUMIDITY LEVELS/. RAP MODEL
SOUNDING OVERALL SEEMS TILTED IN FAVOR OF THE DRY AIR MASS...WITH THE
MORE DEGRADED CONDITIONS STAYING TO OUR NORTH AND WEST /AS IS
ALREADY OCCURRING FOR MANY TERMINALS ON THE ONTARIO PENINSULA/...WHERE
HIGHER DEWPOINTS WERE ABLE TO ADVECT IN EARLIER. I HAVE TO RESPECT
THE STILL FAIR SET UP FOR KELM...AND INCLUDED TEMPO IFR 11Z-13Z...BUT
OTHERWISE HELD THE LINE AT MVFR VIS EARLY THIS MORNING. LIGHT
EASTERLY FLOW WILL ALSO YIELD SOME MVFR VIS FOR A TIME EARLY THIS
MORNING. FOR KRME...WILL HAVE TO WATCH FOR POSSIBLE MVFR LIGHT FOG
BUT NOT IN TAF BECAUSE MOST LIKELY SCENARIO IS VFR.
OUTLOOK...
FRI...MVFR POSSIBLE ALONG AND BEHIND SHOWERY COLD FRONT AFTN/EVE.
FRI NGT...MVFR CIGS. LATE IFR VIS POSS KSYR-KRME FROM LAKE -SHSN.
SAT...MVRF/BRIEF IFR FROM LAKE -SHSN...MAINLY CNY TERMINALS.
SUN...RESTRICTIONS PSBL IN SCT SHRA/SHSN.
MON...MAINLY VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...CMG
NEAR TERM...CMG/RRM
SHORT TERM...CMG
LONG TERM...MDP
AVIATION...MDP
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
105 AM EST THU NOV 22 2012
.SYNOPSIS...
WARM ABOVE AVERAGE TEMPERATURES WILL PREVAIL ACROSS THE REGION ON
THANKSGIVING DAY WITH MANY LOCATIONS EASILY WARMING INTO THE
MIDDLE TO UPPER 50S FOR DAYTIME HIGHS. ABOVE NORMAL TEMPERATURES
WILL QUICKLY COME TO AN END BY FRIDAY AS A STRONG COLD FRONT
SWINGS THROUGH THE REGION. COLD AIR WILL RAPIDLY OVERSPREAD THE
REGION FRIDAY NIGHT AND SATURDAY WITH REDEVELOPING LAKE EFFECT
SNOWS EXPECTED OVER THE UPCOMING WEEKEND.
&&
.NEAR TERM /THROUGH TODAY/...
1030 PM UPDATE...CURRENT FORECAST REMAINS IN GOOD SHAPE, JUST
LOWERED OVERNIGHT LOWS BY 2-4 DEGREES AS WEAK BOUNDARY LAYER FLOW
WILL PERSIST UNTIL DAYBREAK EVEN ALONG THE LAKE PLAIN. WITH DEW
POINTS CONTINUING TO FALL IN TANDEM WITH SFC TEMPS, DENSE FOG
FORMATION IS NOT EXPECTED.
530 PM UPDATE...CLEAR SKIES AND LIGHT WINDS HAVE ALLOWED TEMPS TO
FALL QUICKLY LATE THIS AFTERNOON. AT PENN YAN AND ELMIRA TEMPS
FELL 10 AND 13 DEGREES RESPECTIVELY DURING THE PAST HOUR. ADJUSTED
TEMP GRIDS TO REFLECT THIS OTHERWISE FORECAST IN GOOD SHAPE WITH
NO OTHER CHANGES.
PREVIOUS DISC...
VISIBLE SATELLITE IMAGERY SHOWING MOSTLY CLEAR SKIES ACROSS THE
REGION THIS AFTERNOON AS SFC RIDGING ASSOCIATED WITH CANADIAN
MARITIMES HIGH PRESSURE CONTINUES TO EXTEND SOUTHWEST OVER OUR
AREA. WITH ABUNDANT SUNSHINE PREVAILING OVERHEAD...TEMPS HAVE WARMED
INTO THE LOWER 50S ACROSS MUCH OF THE AREA WHICH IS ANYWHERE
BETWEEN 5-10 DEGREES ABOVE NORMAL. WITH A DRY AIRMASS IN
PLACE...TEMPS WILL FALL OFF QUICKLY THIS EVENING WITH OVERNIGHT
LOWS EXPECTED TO REACH THE LOWER TO MIDDLE 30S. THE ONLY CONCERN
WITH THE GOING FCST OVERNIGHT WILL BE POSSIBLE FOG FORMATION
TOWARDS MORNING. UPSTREAM OBSERVATIONS THIS MORNING SHOWED AN
EXPANSIVE AREA OF FOG ACROSS THE UPPER MIDWEST WHERE VISIBILITIES
WERE NEAR ZERO ACROSS THE GREATER CHICAGO AREA FOR HRS. THIS MOIST
LOW-LEVEL AIRMASS WILL ADVANCE EAST OVERNIGHT WHERE IT WILL
ENCOUNTER MORE AND MORE DRY AIR WITH FURTHER EASTWARD PROGRESS.
FOR NOW...STATISTICAL GUIDANCE MAKING NO SUGGESTION OF ANY FOG
FORMATION ACROSS OUR AREA HOWEVER EVENING SHIFT WILL HAVE TO
MONITOR TRENDS ACCORDINGLY.
UNSEASONABLY WARM TEMPS TO CONTINUE RIGHT THROUGH THANKSGIVING DAY
WHERE 925-MB THERMAL RIDGING CHARACTERIZED BY TEMPS APPROACHING 9C
WILL SUPPORT AFTERNOON HIGH TEMPS REACHING THE MIDDLE TO UPPER 50S
ACROSS MANY AREAS. THAT SAID...HAVE ELECTED TO INCREASE TEMPS A
FEW DEGREES WITH UPPER 50S NOW BEING FORECAST ACROSS THE LAKE
PLAIN WHERE DOWNSLOPE COMPRESSIONAL WARMING MAY ALLOW TEMPS TO
APPROACH 60. FROM A CLIMATOLOGICAL STANDPOINT...IF SYR WERE TO
HIT 60 ON THANKSGIVING DAY...IT WILL BE THE FIRST TIME SINCE 2004
WHEN THE MERCURY CLIMBED TO A BALMY 63 DEGREES. DRY CONDITIONS TO
CONTINUE RIGHT THROUGH THANKSGIVING NIGHT WITH OVERNIGHT LOWS
EXPECTED TO FALL INTO THE MIDDLE TO UPPER 30S.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY/...
BIG CHANGES ON THE WAY BEGINNING FRI AS A WELL ADVERTISED COLD
FRONT SWINGS THROUGH THE AREA. PRECIP ALONG AND AHEAD OF THE FRONT
WILL BEGIN WORKING THROUGH THE WESTERN ZONES DURING THE LATE
MORNING BEFORE CLEARING THE ENTIRE CWA BY EARLY EVENING. WITH THE
FRONT MOVING THROUGH RAPIDLY...EXPECT PRECIP TOTALS TO GENERALLY
RANGE BELOW TWO TENTHS OF AN INCH. FOR AREAS MAINLY ALONG AND
WEST OF I-81...TEMPS WILL FALL RAPIDLY THROUGH THE MID/LATE
AFTERNOON AS STRONG COLD AIR ADVECTION OVERSPREADS THE REGION IN
THE FRONT/S WAKE.
BIG STORY HOWEVER WILL BE THE RAPID COOL DOWN EXPECTED FOLLOWING
FROPA AND THE REDEVELOPMENT OF LAKE EFFECT SNOW BEGINNING EARLY SAT
MORNING. INITIAL WIND DIRECTION FOLLOWING FROPA WILL FOLLOW A
WESTERLY TRAJECTORY WHICH WILL FAVOR THE SOUTHERN TUG HILL THROUGH
ROUGHLY 12Z ON SAT. FOLLOWING THIS...BOTH NAM AND GFS FCST MODELS
SHOW A SFC TROUGH DROPPING SOUTH IN CYCLONIC FLOW WHICH WILL ALLOW
WINDS TO SHIFT AROUND TO THE NORTHWEST THROUGH THE MORNING. AS
THIS OCCURS...850-MB TEMPS WILL CONTINUE TO COOL WITH VALUES
REACHING NEAR -13C BY 00Z SUN. INSPECTION OF SEVERAL GFS AND NAM
BUFKIT SOUNDINGS REVEALS AN INCREASINGLY FAVORABLE ENVIRONMENT FOR
LAKE EFFECT SNOWS THROUGH THE DAY ON SAT WITH GOOD SATURATION
THROUGH THE FAVORABLE DENDRITIC SNOW GROWTH REGION. THAT
SAID...HAVE DRAWN HIGHEST POPS FROM SOUTHERN ONEIDA COUNTY WEST
THROUGH THE CENTRAL FINGER LAKES TO INCLUDE THE
ITHACA AND SYRACUSE METRO AREAS. FROM THIS VANTAGE
POINT...SEVERAL INCHES OF FRESH LAKE EFFECT SNOWFALL WILL BE
POSSIBLE AS TEMPS STRUGGLE TO REACH THE MID 30S FOR DAYTIME HIGHS.
FOR NOW...IT LOOKS LIKE LAKE SNOWS WILL CONTINUE RIGHT THROUGH SAT
NGT WHICH WILL OBVIOUSLY JUST ADD TO SNOW TOTALS. WOULD NOT BE
SURPRISED IF ADVISORIES EVENTUALLY GET POSTED HOWEVER ITS MUCH TO
EARLY FOR THIS NOW. IN ANY EVENT...WILL HIGHLIGHT SNOW ACCUMULATION
POTENTIAL IN THE HWO TO INCREASE AWARENESS FOR HOLIDAY WEEKEND
TRAVELERS.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
130 PM UPDATE...CLD AIR SETS IN BHND FRONTAL PASSAGE LATE IN THE
WEEK, CONTINUING THRU THE WEEKEND. H8 TEMPS DROP DOWN TO BTWN -10C
TO -12C LVG MODERATE LK INSTABILITY IN ITS WAKE. FLOW ALIGNS FM
310-320 DEGREES WITH FINGER LKS AREA UNDER THE GUN FOR CONTD LK
EFFECT SNOW THRU SUN AFTN. APPEARS AS THO WINDS SHIFT ARND TO THE
SOUTHWEST, MVG SNOW SHOWERS NORTH OF THE CWA SUN NGT.
MED RANGE MODELS AGREE ON S/WV DROPPING INTO THE INTERMOUNTAIN
STATES EARLY NEXT WEEK. THIS WL INDUCE SFC LOW DVLPMNT BY 00Z TUE
IN VICINITY OF MID-MS VLY. 00Z EURO IS QUICKER TO MV THIS SFC LOW
NORTH TWD THE AREA BY ABOUT 12 HRS. EURO BRINGS IT UP TO THE WEST
OF OUR AREA WITH RAIN OR SNOW EXPECTED DRG THE DAY ON TUESDAY. 12Z
GFS SUPPRESSES THE LOW FURTHER TO THE SOUTH, THOUGH H8 TEMPS RISE
ABV 0C ACRS PORTIONS OF OUR AREA. THUS HV GONE WITH CHC POPS THRU
12Z WED WITH A MIX OF RAIN OR SNOW, TOO EARLY TO SAY AT THIS
POINT.
TEMPS WL BE MORE TYPICAL OF VALUES EXPECTED FOR LATE NOVEMBER.
HIGHS IN THE U30S AND LOWS IN THE MID-20S.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
06Z UPDATE...
VFR FOR ENTIRE TAF PERIOD...EXCEPT FOR QUESTION OF EARLY MORNING
VALLEY FOG DEVELOPMENT IN KELM...AND SOME MVFR VIS FOR KITH. GREAT
RADIATIONAL COOLING SET UP AND SHARP INVERSION...SUPPORTIVE OF
KELM VALLEY FOG...IS COMPETING WITH VERY ATMOSPHERE /AFTER YET
ANOTHER DAYTIME OF NO PRECIP AND LOW HUMIDITY LEVELS/. RAP MODEL
SOUNDING OVERALL SEEMS TILTED IN FAVOR OF THE DRY AIR MASS...WITH THE
MORE DEGRADED CONDITIONS STAYING TO OUR NORTH AND WEST /AS IS
ALREADY OCCURRING FOR MANY TERMINALS ON THE ONTARIO PENINSULA/...WHERE
HIGHER DEWPOINTS WERE ABLE TO ADVECT IN EARLIER. I HAVE TO RESPECT
THE STILL FAIR SET UP FOR KELM...AND INCLUDED TEMPO IFR 11Z-13Z...BUT
OTHERWISE HELD THE LINE AT MVFR VIS EARLY THIS MORNING. LIGHT
EASTERLY FLOW WILL ALSO YIELD SOME MVFR VIS FOR A TIME EARLY THIS
MORNING. FOR KRME...WILL HAVE TO WATCH FOR POSSIBLE MVFR LIGHT FOG
BUT NOT IN TAF BECAUSE MOST LIKELY SCENARIO IS VFR.
EXTENDED OUTLOOK...
FRI...MVFR POSSIBLE ALONG AND BEHIND SHOWERY COLD FRONT AFTN/EVE.
FRI NGT...MVFR CIGS. LATE IFR VIS POSS KSYR-KRME FROM LAKE -SHSN.
SAT...MVRF/BRIEF IFR FROM LAKE -SHSN...MAINLY CNY TERMINALS.
SUN...RESTRICTIONS PSBL IN SCT SHRA/SHSN.
MON...MAINLY VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...CMG
NEAR TERM...CMG/RRM
SHORT TERM...CMG
LONG TERM...PVN
AVIATION...MDP
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
1241 AM EST THU NOV 22 2012
.SYNOPSIS...
HIGH PRESSURE WILL KEEP WARM AND DRY CONDITIONS ACROSS THE REGION
THROUGH THANKSGIVING. A COLD FRONT WILL MOVE THROUGH THE AREA
FRIDAY MORNING. TEMPERATURES WILL FALL FRIDAY AFTERNOON AND BE
WELL BELOW NORMAL OVER THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
FOR THE EVENING UPDATE ADDED PATCHY TO AREAS OF FOG MAINLY FOR
THE NORTHWESTERN PORTIONS OF THE FORECAST AREA AFTER MIDNIGHT
TONIGHT. TEMP/DEWPOINT SPREADS ARE NARROWING RAPIDLY THIS EVENING
ACROSS THESE AREAS WITH FOG ALREADY DEVELOPING JUST TO OUR
NORTHWEST. THIS TREND HAS BEEN INDICATED WELL BY THE RAP SURFACE RH
FIELDS THIS AFTERNOON AND THEREFORE IS BEING FOLLOWED FOR THE FOG
FORECAST FOR TONIGHT. OTHERWISE MADE NO ADJUSTMENTS TO THE
PREVIOUS FORECAST EXCEPT ADDING A FEW CIRRUS TO THE SKY GRIDS.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH FRIDAY NIGHT/...
SOUTHERLY WINDS WILL OCCUR BETWEEN RETREATING HIGH PRESSURE AND AN
ADVANCING COLD FRONT THURSDAY AND THURSDAY EVENING. THIS WILL LEAD
TO WELL ABOVE NORMAL TEMPERATURES ONCE AGAIN. HIGH CLOUDS WILL
START STREAMING INTO THE REGION DURING THIS PERIOD.
THE COLD FRONT WILL MOVE INTO WESTERN SECTIONS VERY LATE THURSDAY
NIGHT AND CROSS THE REST OF THE FORECAST AREA FRIDAY MORNING.
THERE WILL BE SHOWERS WITH THE COLD FRONT. BUT THERE IS SOME
UNCERTAINTY ABOUT COVERAGE OF MEASURABLE RAIN. SO HAVE GONE HIGH
CHANCE AND LOW LIKELY FOR THE REGION LATE THURSDAY NIGHT AND
FRIDAY MORNING. SHOWERS WILL CLEAR OUT BY MIDDAY FRIDAY WITH
CLOUDS DECREASING. TEMPERATURES SHOULD STAY RATHER WARM UNTIL
FRONTAL PASSAGE EXCEPT FOR FAR EASTERN/SOUTHEASTERN COUNTIES WHERE
READINGS MAY DROP OFF EARLY THURSDAY NIGHT. LOOKS LIKE A SITUATION
WHERE THERE COULD BE 13Z LOWS AND 12Z HIGHS IN MANY LOCATIONS WITH
READINGS FALLING THROUGH THE REST OF FRIDAY. WINDS WILL BE GUSTY
BEHIND THE COLD FRONT WITH WIND CHILL VALUES DROPPING INTO THE
UPPER 20S TO MID 30S BY LATE IN THE DAY.
WINDS WILL DIMINISH SOMEWHAT FRIDAY NIGHT. ADDITIONAL CLOUD COVER
MAY SPREAD INTO THE REGION WITH COLD AIR ADVECTION AND CYCLONIC
FLOW OVER THE GREAT LAKES. FELT THAT GFS MOS LOWS LOOKED MORE
REASONABLE IN THIS SCENARIO.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
COLD AIR MASS WILL BE IN PLACE ACROSS THE AREA ON SATURDAY WITH HIGH
TEMPERATURES ONLY IN THE MIDDLE 30S. WITH WINDS OFF OF LAKE
MICHIGAN ON SATURDAY SOME LIGHT LAKE EFFECT SNOW SHOWERS WILL BE
POSSIBLE ACROSS NORTHERN PORTIONS OF THE FA. H8 WINDS WILL BECOME
MORE WESTERLY SATURDAY EVENING AND PRECIPITATION CHANCES WILL COME
TO AN END ACROSS THE FA. CLOUD COVER WILL DECREASE ACROSS THE AREA
SATURDAY NIGHT ALLOWING TEMPERATURES TO DROP DOWN INTO THE LOW 20S
ACROSS MOST LOCATIONS. WARMER AIR WILL GRADUALLY START TO WORK INTO
THE AREA LATE DURING THE OVERNIGHT SATURDAY NIGHT AND THIS SHOULD
HELP TO KEEP TEMPERATURES FROM FALLING INTO THE TEENS. TEMPERATURES
CLIMB INTO THE 40S ON SUNDAY ACROSS THE AREA WITH SW FLOW HOWEVER
THESE VALUES ARE STILL BELOW NORMAL FOR THIS TIME OF YEAR.
THE MODELS START TO DIVERGE WITH THE STORM SYSTEM BEGINNING TO
IMPACT THE AREA ON MONDAY. MODELS HAVE SHOWN QUITE A BIT OF RUN TO
RUN INCONSISTENCY WITH THIS FEATURE. THE LATEST 12Z ECMWF HAS
SHIFTED THE LOW QUITE A BIT FURTHER SOUTH FROM THE PREVIOUS MODEL
SOLUTIONS AND HAVE DECIDED NOT TO JUMP ON THIS LATEST RUN JUST YET.
INSTEAD...WENT WITH A 12Z GFS 00Z ECMWF BLEND. PRECIPITATION WILL
BEGIN TO MOVE INTO THE AREA ON MONDAY WITH A GREATER COVERAGE IN
PRECIPITATION EXPECTED MONDAY EVENING INTO TUESDAY. PRECIPITATION
WILL GENERALLY BE IN THE FORM OF RAIN THROUGH THE DAYTIME HOURS ON
TUESDAY EXCEPT FOR A LITTLE SNOW THAT MAY MIX IN AT TIMES ACROSS THE
NORTH MONDAY INTO MONDAY NIGHT. WITH THE 12Z GFS 00Z ECMWF BLEND
HAVE THE AREA OF LOW PRESSURE MOVING ALONG AND JUST NORTH OF THE
INTERSTATE 71 CORRIDOR ON TUESDAY. COLDER AIR WILL QUICKLY WORK
INTO THE AREA TUESDAY NIGHT AND ANY RESIDUAL PRECIPITATION WILL
BEGIN TO CHANGE OVER TO SNOW ACROSS THE REGION. DRY CONDITIONS WILL
RETURN TO THE AREA BY WEDNESDAY MORNING.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
HIGH PRESSURE CENTERED OVER THE REGION ATTM WILL SLIP EAST TODAY.
LIGHT WINDS AND CLEAR SKIES WILL ALLOW SOME FOG FORMATION. KEPT
FOG AT THE FOGGIER LOCATIONS...LUK AND ILN. ALLOWED LUK TO FALL TO
IFR IN FOG...BUT KEPT ILN MVFR ATTM.
H5 RIDGE ALSO OVER THE REGION WILL BREAK DOWN TODAY IN RESPONSE TO
A S/W KICKING OUT OF THE PLAINS. HIGH LEVEL MOISTURE WILL BEGIN
TO INCREASE DURING THE AFTN HOURS. AC DECK IS EXPECTED T0 WORK IN
AFT 00Z.
CDFNT SWINGING UP THE OH VALLEY WILL PUSH 4-5KFT CIGS INTO CVG AFT
06Z...WITH SCT SHRA AFT 10Z.
OUTLOOK...MVFR CEILINGS AND VISIBILITIES POSSIBLE FRIDAY. MVFR
CEILINGS POSSIBLE SATURDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...LATTO
SHORT TERM...
LONG TERM...NOVAK
AVIATION...SITES
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
1045 PM CST WED NOV 21 2012
.DISCUSSION...
STILL A LITTLE MIXY WITH SOUTHWESTERLY LOW LEVEL JET OVER EASTERN
PART OF THE AREA. THIS HOLDING TEMPERATURES UP THIS EVENING...WITH
READINGS STILL IN THE MID 50S TO LOWER 60S AS OF 03Z. MODELS DO NOT
HAVE A GREAT GRASP ON THIS...WITH RAP THE CLOSEST THOUGH STILL A FEW
DEGREES SHY AT 03Z. TREND IN THIS MODEL SEEMS REASONABLE THOUGH...
WITH SLOW FALL AHEAD OF PRE-FRONTAL TROUGH...WHICH WILL TURN WINDS
MORE WESTERLY AND SOMEWHAT LIGHTER OVERNIGHT. SHOULD SEE GREATER
FALL AFTER THIS TROUGH PASSAGE...AND WITH COLD ADVECTION BEGINNING
TO PUSH INTO WESTERN PARTS OF THE CWA PRIOR TO DAYBREAK...WILL LET
GOING LOWS RIDE WITH MINIMAL CHANGES. UPDATED GRIDS/PFM HAVE BEEN
SENT.
&&
.AVIATION.../FOR THE 06Z TAF ISSUANCE/
MAINLY VFR CONDITIONS EXPECTED THROUGH THE TAF PERIOD. SOUTHERLY
WINDS OVERNIGHT WILL TRANSITION TO NORTHWESTERLY AND INCREASE EARLY
ON THURSDAY...WITH GUSTS OF 30 TO 40 KTS LIKELY BY LATE MORNING AND
AFTERNOON. REMOVED LLWS AT KSUX AS GUSTY SURFACE WINDS ARE
CURRENTLY LIMITING SHEAR...HOWEVER IF SURFACE WINDS ARE ABLE TO DROP
OFF OVER THE NEXT COUPLE HOURS LLWS MIGHT NEED TO BE
REINTRODUCED...AS STILL SEEING CLOSE TO A 45 KT JET NEAR 1K FEET.
SHOULD SEE SOME STRATUS FORM BEHIND THE FRONT TOMORROW AS WELL.
CURRENTLY THINKING ANY MVFR CIGS STAY NORTH OF OUR CWA...ALTHOUGH
WILL HAVE TO WATCH KHON AND TO A LESSER EXTENT KFSD...AS THEY COULD
SEE A BRIEF PERIOD OF MVFR CIGS RIGHT BEHIND THE FRONT LATE TOMORROW
MORNING INTO THE EARLY AFTERNOON HOURS...BEFORE DRYING AND CLEARING
TAKES PLACE. WINDS WILL REMAIN GUSTY THROUGH THE EVENING HOURS...BUT
SHOULD DROP A TAD. BUT AS A SECONDARY PUSH OF COLD AIR MOVES
THROUGH...WE SHOULD SEE WINDS KICK UP A NOTCH WITH GUSTS BACK AROUND
35 KTS LATER IN THE EVENING INTO THE OVERNIGHT. /CHENARD
&&
.PREV DISCUSSION.../ISSUED AT 241 PM CST/
BRISK SOUTH SOUTHWESTERLY FLOW WILL CONTINUE ACROSS MUCH OF THE AREA
TONIGHT WITH THE APPROACH OF A SURFACE TROUGH FROM THE WEST. THIS
WILL ALLOW FOR WINDS TO STAY UP OVERNIGHT...MORE SO IN THE
EAST...AND IT WILL BE A MILD NIGHT WITH LOWS PRIMARILY IN THE 40S.
THE SURFACE TROUGH/FRONTAL BOUNDARY WILL SWING THROUGH THE AREA ON
THURSDAY...AND WITH STRONG COLD AIR ADVECTION/STEEP LOW LEVEL LAPSE
RATES/WINDS GENERALLY 40 TO 45 KTS AT THE TOP OF THE MIXED LAYER/AND
A TIGHTENING GRADIENT IT WILL BE A WINDY DAY...AND EXPANDED THE WIND
ADVISORY OVER THE ENTIRE CWA. WHILE THE ADVISORY WILL BE MARGINAL IN
SOME AREAS...AND STRONGEST WINDS MAY ONLY PERSIST FOR 2 OR 3 HOURS
WITH THE FRONTAL PASSAGE...FOR THE SAKE OF SIMPLICITY AND
COORDINATION WITH SURROUNDING OFFICES ELECTED TO INCLUDE THE ENTIRE
AREA AS CRITERIA IS EXPECTED TO BE CLOSE ENOUGH. WHILE THE COLDEST
AIR WILL NOT COME IN UNTIL THURSDAY NIGHT...WITH 925 MB TEMPERATURES
PROGGED TO BE A GOOD 10 TO 15 DEGREES C COOLER ON THURSDAY AFTERNOON
OVER TODAY...WILL HAVE HIGHS RANGING FROM THE UPPER 40S TO
MID 50S ACROSS THE AREA...THOUGH IT WILL OBVIOUSLY FEEL COLDER WHEN
THE WINDS ARE FACTORED IN.
A STRONG SURGE OF COLD AIR WILL MOVE SOUTH ON THURSDAY NIGHT ALONG
WITH GUSTY NORTHWEST WINDS. MODELS IN PRETTY GOOD AGREEMENT WITH THE
AMOUNT OF COOLING...JUST SOME MINOR DIFFERENCES ON THE TIMING OF THE
FRONT. THE NAM SEEMS TO HANDLE THESE LOW LEVEL FRONTAL FEATURES BEST
THIS TIME OF YEAR SO USED THAT TO ACCOUNT FOR THE SOMEWHAT NON
DIURNAL NATURE OF TEMPERATURES AS THEY DROP THROUGH THE EARLY
MORNING OF FRIDAY BEFORE SLOWLY RISING THROUGH THE DAY. LOWS WILL BE
MODERATED A BIT BY THE STRONG FLOW SO WENT CLOSEST TO THE CONSRAW
OUTPUT WHICH HANDLES WINDY NIGHTS THE BEST...SO MAINLY LOWER TO MID
20S FOR LOWS. HIGH TEMPERATURES FRIDAY WILL NOT REBOUND MUCH AS COLD
ADVECTION CONTINUES AND CLOUDS IN THE EAST ARE SLOW TO ERODE. MAINLY
AIMING FOR 250 TO 30 IN THE EAST AND 30 TO 35 IN THE WEST.
FRIDAY NIGHT INTO SATURDAY WILL SEE A FAST MOVING SURFACE HIGH
PRESSURE MOVE THROUGH WITH BREEZY SOUTHERLY FLOW DEVELOPING ON
SATURDAY. TWEAKED LOWS DOWN JUST A TOUCH IN THE EASTERN CWA AND LEFT
THEM ABOUT AS IS IN THE WESTERN CWA. WITH THE RETURN FLOW SETTING UP
IN THE FAR SOUTH AND WEST CWA ALSO HAVE GRADUALLY WARMING
TEMPERATURES IN THOSE AREAS THROUGH SUNRISE. BY SATURDAY THIS STRONG
SOUTHERLY FLOW WILL BE IN PLACE WITH A FAIRLY STRONG THERMAL
GRADIENT DEVELOPING ACROSS THE CWA. EXPECTING TEMPERATURES TO
STRUGGLE A BIT IN THE EAST WHERE SOUTHERLY WINDS WILL BE SLOW TO SET
UP...SO ONLY MID 30S. IN THE SOUTHWEST CWA A SURGE OF WARMER AIR
SHOULD ALLOW TEMPERATURES TO BUMP UP INTO THE LOWER 50S.
IN THE LATTER PERIODS(SUN/WED)...A TROUGH OF LOW PRESSURE WILL DIG
INTO THE CENTRAL ROCKIES SUNDAY AFTERNOON THEN SPREAD ACROSS THE
CENTRAL PLAINS SUNDAY NIGHT INTO MONDAY. WHILE THERE WILL BE A SMALL
CHANCE FOR LIGHT SNOW DURING THIS TIME...WITH SO MUCH NORTHWEST JET
ENERGY UPSTREAM FEEL THAT THE WAVE MAY DIG A LITTLE FARTHER SOUTH
THAN MODELS CURRENTLY PROJECT SO DO NOT PLAN ON INCREASING
PROBABILITIES FOR MEASURABLE SNOWFALL. IF THE WAVE DOES DIVE A
LITTLE FARTHER SOUTHWEST ON SUNDAY THE AMOUNT OF WARM AIR THAT MAKES
IT THIS FAR NORTH WILL BE MINIMAL WITH A NORTH TO NORTHEAST WIND
DEVELOPING THROUGH THE DAY. WILL CONTINUE TO KEEP HIGHS FAIRLY COOL
BUT SEASONAL FROM THE UPPER 30S NORTH TO THE MID 40S SOUTH. AS THE
WAVE PASSES ON SUNDAY NIGHT COLDER AIR WILL POUR INTO THE REGION
SETTING UP A FAIRLY COLD MONDAY THROUGH THURSDAY TIME PERIOD. WILL
CONTINUE TO LEAN TOWARDS THE MORE CONSISTENT ECMWF WHICH BUILDS THE
HIGH PRESSURE SOUTH AND IS MORE STUBBORN ABOUT ALLOWING WARM AIR TO
SURGE NORTHEAST AS A WEAK WAVE PASSES ON TUESDAY NIGHT INTO
WEDNESDAY. /08
&&
.FIRE WEATHER.../ISSUED AT 333 PM CST/
THANKSGIVING DAY WILL SEE VERY STRONG NORTHWEST WINDS DEVELOP DURING
THE DAY AND WITH VERY DRY CONDITIONS A VERY HIGH FIRE DANGER WILL BE
IN PLACE. THE STRONGEST WINDS WILL BE IN CENTRAL SOUTH DAKOTA DOWN
THE MISSOURI RIVER VALLEY THROUGH EARLY AFTERNOON...THEN TRANSITION
INTO EASTERN SOUTH DAKOTA...SOUTHWEST MINNESOTA AND NORTHWEST IOWA
FROM EARLY AFTERNOON INTO THE EVENING.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
IA...WIND ADVISORY FROM NOON TO 6 PM CST THURSDAY FOR IAZ001>003-
012>014-020>022-031-032.
MN...WIND ADVISORY FROM NOON TO 6 PM CST THURSDAY FOR MNZ071-072-080-
081-089-090-097-098.
NE...WIND ADVISORY FROM 9 AM TO 6 PM CST THURSDAY FOR NEZ013.
WIND ADVISORY FROM NOON TO 6 PM CST THURSDAY FOR NEZ014.
SD...WIND ADVISORY FROM 9 AM TO 6 PM CST THURSDAY FOR SDZ038-050-052-
053-057>060-063>066-068>070.
WIND ADVISORY FROM NOON TO 6 PM CST THURSDAY FOR SDZ039-040-
054>056-061-062-067-071.
&&
$$
AREA FORECAST DISCUSSION
NWS AMARILLO TX
1119 PM CST WED NOV 21 2012
.AVIATION...
06Z TAF CYCLE
UPPER TROUGH TO PUSH THROUGH THE PANHANDLES BETWEEN 12Z AND 18Z
THURSDAY WITH NORTHWESTERLY UPPER FLOW BEHIND THE DEPARTING UPPER
TROUGH LATE THURSDAY AND THURSDAY NIGHT. VFR CONDITIONS WITH
CONSIDERABLE MID AND HIGH LEVEL CLOUDINESS TONIGHT...AND CLEAR TO
SCATTERED HIGH LEVEL CLOUDS BY THURSDAY AFTERNOON AND THURSDAY NIGHT.
LOW LEVEL SOUTHERLY JET OVER THE PANHANDLES TONIGHT WILL ALLOW FOR
GUSTY SOUTHERLY WINDS 15 TO 25 KNOTS WITH OCCASIONAL HIGHER
GUSTS...THEN COLD FRONT MOVES THROUGH THE GUYMON AND DALHART TAF
SITES AROUND 13Z TO 15Z THURSDAY SHIFTING THE WINDS TO NORTHERLY 15
TO 25 KNOTS WITH HIGHER GUSTS. COLD FRONT MOVES THROUGH THE AMARILLO
TAF SITE BETWEEN AROUND 16Z AND 18Z THURSDAY WITH WINDS BECOMING
NORTHERLY 15 TO 25 KNOTS WITH HIGHER GUSTS. NORTHERLY WINDS GRADUALLY
DIMINISH BETWEEN 21Z THURSDAY AND 02Z FRIDAY TO AROUND 10 TO 20
KNOTS UNTIL 06Z FRIDAY.
SCHNEIDER
&&
.PREV DISCUSSION... /ISSUED 959 PM CST WED NOV 21 2012/
UPDATE...
QUICK UPDATE TO TWEAK OVERNIGHT WINDS...TEMPS...AND DEWPOINTS UPWARD BASED
ON CURRENT TRENDS.
KB
PREV DISCUSSION... /ISSUED 518 PM CST WED NOV 21 2012/
AVIATION...
00Z TAF CYCLE
UPPER TROUGH WILL MOVE ACROSS THE TEXAS AND OKLAHOMA PANHANDLES
TONIGHT PRODUCING CONSIDERABLE MID AND HIGH LEVEL CLOUDINESS AND
USHERING IN A COLD FRONT THANKSGIVING DAY MORNING. VFR CONDITIONS ARE
EXPECTED ALONG WITH SOUTHERLY WINDS 15 TO 20 KNOTS WITH SOME HIGHER
GUSTS POSSIBLE TONIGHT...THEN WINDS SHIFTING TO THE NORTHWEST AND
NORTH 15 TO 25 KNOTS WITH HIGHER GUSTS AFTER 14Z TO 17Z THANKSGIVING
DAY. WIND SPEEDS ARE EXPECTED TO GRADUALLY DIMINISH AFTER 20Z TO 22Z
THANKSGIVING DAY TO AROUND 15 KNOTS.
SCHNEIDER
PREV DISCUSSION... /ISSUED 415 PM CST WED NOV 21 2012/
DISCUSSION...
CONTINUED DRY CONDITIONS AND PERIODIC FRONTAL PASSAGES HIGHLIGHT THE
FORECAST PERIOD.
SOUTHWESTERLY WINDS AND CLOUD COVER HAVE INCREASED TODAY IN ADVANCE
OF A SHORTWAVE TROUGH NOW EJECTING THROUGH THE AMBIENT SOUTHWESTERLY
FLOW ALOFT. WHILE MOST OF THE FORCING/ASCENT AND MEANINGFUL RAIN
CHANCES ASSOCIATED WITH THIS FEATURE WILL REMAIN WELL SOUTH OF THE
AREA...SOME ENHANCED VORTICITY/DEEPENING OF THE TROUGH HAS EMERGED THIS
AFTERNOON OVER CENTRAL NEW MEXICO. ISOLATED HIGH-BASED CONVECTION HAS
DEVELOPED NEAR ROSWELL. ALL NWP SOLUTIONS MINIMIZE PROSPECTS FOR
PRECIPITATION IN THE PANHANDLES AS THIS TRANSLATES OVER THE REGION
TONIGHT. ONLY THE RAP DEPICTS THE SMALLEST HINT OF QPF OVER THE
SOUTHWESTERN PANHANDLE. THUS WE HAVE MAINTAINED A DRY FORECAST WITH
GRIDDED POPS AT/BELOW 10 PERCENT.
A FRONT IS EXPECTED TO PUSH ACROSS THE PANHANDLES AFTER 12-15Z
THURSDAY IN WAKE OF THE PASSING SHORTWAVE TROUGH AXIS. 3-HR PRESSURE
RISES AROUND 4 MB OVER KANSAS WILL SUPPORT POST FRONTAL WINDS OF 15
TO 25 MPH...ESPECIALLY OVER THE OKLAHOMA PANHANDLE AND THE NORTHERN
TEXAS PANHANDLE. ALL INDICATIONS OF SUFFICIENT LIFT/MOISTURE TO
SUPPORT CONVECTION ALONG THE FRONT ARE DISPLACED WELL EAST AND SOUTH
OF THE REGION.
A 1035-1037 MB CONTINENTAL SURFACE HIGH WILL PUSH SOUTHWARD THROUGH
THE PLAINS IN WAKE OF THE FRONT. THIS WILL RESULT IN NOTABLY COOLER
TEMPERATURES /SOME 5 DEGREES BELOW SEASONAL AVERAGES/ BY FRIDAY. THE
COOL SURFACE RIDGE WILL TRANSLATE SOUTHEAST TOWARD THE LOWER
MISSISSIPPI VALLEY...LENDING TOWARD TEMPERATURE MODERATION OVER THE
PANHANDLES THROUGH THE WEEKEND. THIS AS LOW AMPLITUDE RIDGING OVER
THE WEST RESULTS IN MODEST NORTHWESTERLY FLOW OVER THE CENTRAL/SOUTHERN
PLAINS AND LEE TROUGHING.
ATTENTION THEN SHIFTS TOWARD A SHORTWAVE TROUGH AND ASSOCIATED FRONTAL
PASSAGE EARLY NEXT WEEK. THE INITIAL FRONTAL PASSAGE WILL OCCUR DURING
THE LATE SUNDAY/EARLY MONDAY TIMEFRAME...AND MAY RESULT IN PROBLEMATIC
TEMPERATURE FORECASTS INITIALLY. THE FRONT WILL FINALLY PUSH SOLIDLY
THROUGH BY LATE MONDAY AS THE APPROACHING SHORTWAVE TROUGH AMPLIFIES
IN NORTHWESTERLY FLOW. SOME SOLUTIONS GENERATE LIGHT QPF IN PROXIMITY
TO THE NORTHERN AND EASTERN PANHANDLES...BUT CONFIDENCE IN SUFFICIENT
FORCING/MOISTURE IS NOT HIGH AND THE CURRENT DRY FORECAST CONTINUES TO
APPEAR VALID.
FIRE WEATHER...
ONGOING ELEVATED FIRE WEATHER OVER THE WESTERN AND CENTRAL OKLAHOMA
PANHANDLE AND NORTHWESTERN TEXAS PANHANDLE WILL DIMINISH BY EARLY
EVENING. CONCERNS FOR ELEVATED CONDITIONS WILL AGAIN EXIST THURSDAY...
AS POST FRONTAL WINDS INCREASE INTO THE 15 TO 20 MPH RANGE AND AFTERNOON
HUMIDITY MINIMA DROP TOWARDS 15 PERCENT AGAIN OVER THE WESTERN OKLAHOMA
PANHANDLE AND THE NORTHWESTERN TEXAS PANHANDLE. OTHERWISE...ELEVATED
OR CRITICAL CONDITIONS ARE NOT ANTICIPATED THROUGH THE REMAINDER OF THE
PERIOD.
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
OK...NONE.
&&
$$
11/08
AREA FORECAST DISCUSSION
NWS LINCOLN IL
226 AM CST SAT NOV 24 2012
.DISCUSSION...
ISSUED 225 AM CST SAT NOV 24 2012
LATEST SURFACE MAP SHOWING HIGH PRESSURE RIDGE EXTENDING FROM
OKLAHOMA NORTHWARD INTO MINNESOTA. WIDESPREAD STRATOCUMULUS IN THE
CYCLONIC FLOW OVER THE GREAT LAKES HAS PUSHED SOUTHWARD TO ABOUT A
PONTIAC TO PARIS LINE AS OF 2 AM. LARGE SHIELD OF MID AND HIGH
CLOUDS ALSO DROPPING SOUTHEAST FROM THE NORTHERN AND CENTRAL PLAINS.
THE PRIMARY FORECAST CONCERN INVOLVES THE PRECIPITATION POTENTIAL
MONDAY AND MONDAY NIGHT...INCLUDING ANY WINTER PRECIP TYPES...AS A
STORM SYSTEM PASSES TO OUR SOUTH.
SHORT TERM...TODAY THROUGH MONDAY NIGHT...
LATEST RAP MODEL AND VAD WIND PROFILES AT 925 MB SUGGEST THE
LOWER CLOUDS SHOULD NOT MAKE MUCH FURTHER WESTWARD PROGRESS...AND
BEGIN TO PULL EASTWARD LATER THIS MORNING. HIGH CLOUDS STREAMING
IN FROM THE NORTHWEST WILL YIELD PARTLY TO MOSTLY SUNNY CONDITIONS
TODAY. TEMPERATURES EXPECTED TO REMAIN RATHER CHILLY TODAY WITH
MID TO UPPER 30S COMMON...AS THE RIDGE AXIS MOVES OVERHEAD.
RETURN FLOW EXPECTED TO BEGIN SETTING UP AROUND SUNSET.
TEMPERATURES ACROSS THE WESTERN CWA EXPECTED TO LEVEL OFF BY
MIDNIGHT...AND PERHAPS RISE A COUPLE DEGREES LATE. HIGHS ON SUNDAY
SHOULD BE ABOUT 10-15 DEGREES WARMER.
LARGE UPPER TROUGH OVER THE EASTERN CONUS TO BREAK DOWN THIS
WEEKEND AS SOME AMPLIFICATION TAKES PLACE ALONG THE WEST COAST.
FAST MOVING JET STREAK OF AROUND 75 KNOTS AT 500 MB WILL PUSH A
BOUNDARY ACROSS THE CWA ON SUNDAY...BUT CLOUDS WILL BE THE MAIN
EFFECT FROM IT. OF MORE CONCERN IS A STORM SYSTEM DEVELOPING ALONG
THE TEXAS/OKLAHOMA BORDER LATE SUNDAY NIGHT AND MONDAY. WHILE THE
EVENING MODELS ALL KEEP THE PARENT SURFACE LOW WELL TO OUR
SOUTH...MOISTURE WILL BE DRAWN NORTH AS A SHORTWAVE IN THE
NORTHERN JET STREAM MOVES INTO THE PLAINS. GFS/CANADIAN MODELS
DRAW THE PRECIPITATION AS FAR NORTH AS ABOUT THE I-72 CORRIDOR BY
MONDAY EVENING...WHILE THE NAM/ECMWF MODELS KEEP ALL THE PRECIP TO
OUR SOUTH. THESE LATTER MODELS MAY BE A LITTLE ON THE FASTER
SIDE...ESPECIALLY THE ECMWF...SO WILL LEAN MORE TOWARD THE SLOWER
SOLUTIONS. AS SUCH...WILL HAVE THE HIGHEST POPS ACROSS THE
SOUTHEAST CWA...ESPECIALLY MONDAY AFTERNOON AND NIGHT. FORECAST
SOUNDINGS INDICATE A RAIN TO SNOW TRANSITION MONDAY EVENING ACROSS
THE SOUTHEAST CWA AND LIGHT SNOW ELSEWHERE...BUT A PERSISTENT DRY
NORTHEAST FLOW WILL KEEP PRECIP TOTALS DOWN. HAVE KEPT AREAS
NORTHWEST OF THE ILLINOIS RIVER WITH MAINLY SLIGHT CHANCE
POPS...WHERE HIGH PRESSURE WILL BUILD IN TO THE AREA.
LONG TERM...TUESDAY THROUGH FRIDAY...
MAINLY QUIET CONDITIONS EXPECTED DURING THIS TIME FRAME. UPPER
RIDGING OVER THE WESTERN U.S. SHOULD TRANSITION TO MORE OF A ZONAL
FLOW AS THE WEEK PROGRESSES...WITH MODERATING TEMPERATURES. LONGER
RANGE MODELS PUSH A FAST MOVING SHORTWAVE THROUGH THE STATE LATE
THURSDAY NIGHT OR EARLY FRIDAY. THE GFS IS THE WETTER OF THE
MODELS WITH THIS FEATURE BUT MAINLY KEEPS THE PRECIPITATION JUST
TO OUR NORTH...SO WILL KEEP THE EXTENDED FORECAST DRY.
GEELHART
&&
.AVIATION...
ISSUED 1149 PM CST FRI NOV 23 2012
MVFR CEILINGS CURRENTLY OVER NORTHERN ILLINOIS HAVE BEEN CREEPING
SLOWLY SOUTHWARD THIS EVENING AND ARE NOW NEARING THE I-74 TERMINALS.
CLOUDS ARE BEING PUSHED SOUTHWARD AS A RESULT OF N/NW FLOW ON THE
BACK SIDE OF A DEPARTING UPPER LOW OVER QUEBEC. GIVEN N/NW FLOW
NOTED ON AREA VAD WIND PROFILERS AND CURRENT SATELLITE TRENDS...HAVE
ADDED A PERIOD OF LOW VFR CEILINGS OF 3500FT AT BOTH KBMI AND
KCMI BETWEEN 06Z AND 11Z. CLOUDS WILL DROP S/SE...THEN GRADUALLY
SHIFT EASTWARD EARLY SATURDAY MORNING AS UPPER LOW PULLS FURTHER
AWAY. SKIES WILL THEN BE MOSTLY CLEAR ACROSS THE BOARD...UNTIL
MID/HIGH CLOUDS INCREASE FROM THE WEST DURING THE AFTERNOON/EVENING.
MODELS HAVE BEEN SUGGESTING A PERIOD OF WARM ADVECTION TYPE CLOUDS
AOA 9000FT SPREADING INTO KPIA AND KSPI BY AROUND 18Z...THEN
FURTHER EAST TO KCMI BY 21Z. WINDS WILL INITIALLY BE FROM THE
NORTHWEST AT 5 TO 10KT TONIGHT INTO SATURDAY MORNING...THEN WILL
BACK TO THE SOUTH BY EVENING.
BARNES
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
341 AM EST SAT NOV 24 2012
.SHORT TERM...
FAILED LES RESPONSE ALG WRN PERIPHERY OF LK MI SO FAR OWING TO
DEGREE OF DRY ENTRAINMENT ONGOING OUT OF WI. MOST FVRBL LK SP FETCH
PRECONDITIONING 2 INTENSE BANDS ACRS NRN LWR STRETCHING SEWD INTO
THE THUMB. SOME INDICATION IN RECENT RADAR IMAGERY OF WK BANDING
DVLPG ALG A KMKG-KBIV LINE AND IF THAT INDEED DVLPS AS RUC SOLUTIONS
SUGGEST THAT CONTD SHALLOW BNDRY LYR VEERING SHLD ALLOW THAT TO SAG
SWD THROUGH MID MORNING. HWVR GIVEN THE DEARTH OF ADDNL MSTR ALOFT
WILL BACK POPS OFF CONSIDERABLY.
OTHERWISE CONTD QUITE COLD TDA W/LG AREA OF STRATO CU LOCKED IN
BENEATH FAIRLY SHARP LL INVERSION. FLW BACKS LT AFTN WHICH WILL
ERODE SWRN EDGE AND PROMOTE LIMITED INSOLATION BUT CONSIDERED TOO
LATE TO APPRECIABLE PROMOTE MORE OF A DIURNAL RESPONSE. GREATER CLRG
XPCD GOING INTO THIS EVENING AHD OF INCOMING HIGH CLD SHIELD
ASSOCD/W FAST MOVING DISTURBANCE OVR SWRN CANADA. LOSS OF DEEPER SC
UNDERNEATH ENVELOPING BUT THIN HIGH CLD SHIELD PERPLEXING GIVEN COLD
MOS GUIDANCE IN LIGHT OF SWRLY RTN FLW DVLPG ON BACKSIDE OF
DEPARTING RIDGE AXIS. THUS WILL ONLY MAKE SLIGHT ADJUSTMENTS FOR
TYPICAL LOCAL COLD SPOTS.
UPSTREAM SYS WILL DEAMPLIFY QUICKLY SEWD ON SUN. WAA AHD OF THIS FTR
AND PARTIAL SUN WILL YIELD A BTR DIURNAL RESPONSE W/ANTICIPATED
GREATER MIXING AND GAVE A +1 BUMP HIGHER.
&&
.LONG TERM...MONDAY THROUGH FRIDAY
MAIN FOCUS REMAINS ON DWINDLING CHANCES FOR SNOW WITH SYSTEM NOW
PROGGED TO TRACK THROUGH THE TN/OH VALLEYS LATE MONDAY AFTERNOON
THROUGH TUESDAY MORNING. 12/00Z GFS/GEFS/GEM ITERATIONS HAVE ALL
TRENDED TOWARD THE LESS AMPLIFIED AND THEREFORE FARTHER SOUTH
SOLUTION OF THE ECMWF WITH A SFC LOW TRACK FROM THE SOUTHERN PLAINS
EAST THROUGH THE TN VALLEY. THIS SOUTHERLY TRACK WOULD RESULT IN
DRY/COLD CONDITIONS LOCALLY WITH SFC HIGH PRESSURE BUILDING INTO THE
SOUTHERN GREAT LAKES. HOWEVER...WOULD NOT BE SURPRISED TO SEE MODELS
TREND BACK A LITTLE TO THE NORTH AND MORE AMPLIFIED WITH THIS
POSITIVE PV ANOMALY AS IT DROPS SOUTHEAST INTO THE MIDWEST. INITIAL
PROGRESSIVE POSITIVE TILT AND CONFLUENCE ACROSS THE LAKES WILL KEEP
IT FROM MAKING IT TOO FAR NORTH BUT CANNOT RULE OUT NORTHERN FRINGE
OF PCPN SHIELD CLIPPING OUR AREA. GUIDANCE OFTEN WEAKENS OR LOSES A
STORM IN THE 4-5 DAY PERIOD ONLY TO LATCH BACK ONTO A STRONGER
SOLUTION WITHIN 72 HOURS AS WAVE FINALLY REACHES OUR RADIOSONDE
NETWORK. HAVE BEEN BURNT BY THIS SEVERAL TIMES SO OPTED TO RETAIN
LOWER CHANCE POPS MAINLY MONDAY NIGHT...HIGHEST SOUTH. THIS WILL
NEED TO BE MONITORED CLOSELY GIVEN PROSPECTS FOR A NARROW SWATH OF
ACCUMULATING SNOW ON THE NORTHERN FLANK OF THIS SYSTEM.
ATTENTION FOR THE MID TO LATE WEEK PERIOD WILL TURN TO TEMPERATURES
AND CLOUD COVER. TOUGH FORECAST AS AREA LIKELY TO BE NEAR A FRONTAL
BOUNDARY ON THE SOUTHWESTERN FRINGE OF A RETREATING POLAR
JET...ESPECIALLY BY THURSDAY AND FRIDAY. A DEVELOPING NEGATIVE
NAO/AO WILL HELP MAINTAIN NORTH ATLANTIC/EASTERN CANADA
BLOCKING...WHILE -PNA AND NORTHEAST PACIFIC NEGATIVE HEIGHT ANOMALY
ALLOW RIDGING/WARMTH TO OVERSPREAD THE PLAINS/MIDWEST. WE`LL BE IN
BETWEEN MAKING IT A DIFFICULT FORECAST. GIVEN THE UNCERTAINTIES
OPTED TO LOAD AND GO WITH THE 00Z ALLBLEND WHICH DOESN`T LOOK TOO
BAD AT THIS POINT WITH TEMPS TRENDING UP TO NEAR NORMAL BY
THURSDAY/FRIDAY. CLOUDS WITH ANY MOISTURE STARVED (LOW AMPLITUDE)
SHORTWAVES IN WNW FLOW WILL ALSO IMPACT TEMPS...ESPECIALLY LATE
THURSDAY INTO FRIDAY PER A ECMWF/GFS/GEFS COMPROMISE. GUIDANCE ALSO
PRINTING OUT SOME LIGHT QPF WITH THIS WAVE BUT WILL HOLD OFF ADDING
ANY POPS GIVEN TIMING DIFFERENCES AND LACK OF MOISTURE/FORCING WITH
SHEARED WAVE(S).
&&
.AVIATION...
MVFR CONDS THIS MORNING WILL GRADUALLY IMPROVE INTO THIS AFTN
W/CONTD LL DRY ENTRAINMENT. SIG SHSN AT KSBN LOOKING MORE AND MORE
DOUBTFUL AND WILL MOST LIKELY BE DROPPED W/12Z ISSUANCE AS DRY AIR
CLEARLY WINNING OUT SO FAR.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS EVENING FOR LMZ043-046.
&&
$$
SHORT TERM...T
LONG TERM...STEINWEDEL
AVIATION...T
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
902 PM CST FRI NOV 23 2012
.DISCUSSION...
COORD WITH WFO BIS AND ADDED A LOW POP FOR -SN IN DVL BASIN AFTER
MIDNIGHT. WARMA ADVECTION AND MID CLOUDS IN WRN ND CAUSING SOME
BRIEF -SN PER RADAR AND THIS SHOULD MOVE INTO DVL BASIN AFTER
MIDNIGHT. SOME OF THIS VERY LIGHT WARM ADV SNOW WILL MOVE INTO
NORTHEAST ND AFTER 12Z PER FCST. 00Z NAM IS MORE BULLISH WITH
LIGHT SNOW CHANCES IN THE AFTN FOR NRN VALLEY INTO NW MN AHD OF
NEXT COLD FRONT.
FOR THE IMMEDIATE FUTURE...TEMPS AND CLOUD COVER PLAYING A BIT OF
HAVOC. LOWER STRATOCU REMAINS IN A MAND FROM PORTAGE MB THROUGH
THE RED RIVER VALLEY INTO NW/WCNTRL MN. CLEARING WEST OF LANGDON
TO MAYVILLE TO WAHPETON LINE HASNT MOVED AND THAT CLEAR AREA IS
NOW SEEING HIGH CLOUDS MOVE IN AND SOME ALTOCU WILL MOVE IN TOWARD
06Z IN WARM ADV ZONE. TEMPS BOTTOMING OUT NOW AROUND -4 OR SO
ROLLA AREA TO 3-5 DEGREES DOWN THROUGH DEVILS LAKE TO COOPERSTOWN
TO WEST OF FARGO. THIS AREA WILL SEE TEMPS SLOWLY RISE OVERNIGHT
AS CLOUDS MOVE IN. IN THE RED RIVER VALLEY LATEST RAP MODEL KEEPS
CLOUDS IN AND RIGHT NOW DONT HAVE MUCH HOPE FOR CLEARING MUCH OF
THE STRATOCU MVFR DECK FOR A WHILE. CLEAR WEDGE IN THE ROSEAU AREA
MAY MAINTAIN ITSELF TONIGHT AND MIGHT EXPAND SOUTH A BIT AND WILL
GO A BIT LOWER TEMPS THAT AREA WITH NR ZERO IN SOUTHEAST MANITOBA.
&&
.PREV DISCUSSION... /ISSUED 628 PM CST FRI NOV 23 2012/
DISCUSSION...
SENDING AN AN EARLY UPDATE AS TEMPS ARE FALLING QUTIE FAST IN
CLEAR WEDGE IN WRN FCST AREA.... -4 TO -6 ALREADY IN THE ROLLA
AREA AND ADJACENT MANITOBA WITH 5 DEGREES DOWN INTO VALLEY CITY-
COOPERSTOWN REGIONS. ALSO DID UP SKY COVER AND HANG ON TO STRATOCU
AND FLURRIES TIL AT LEAST 03Z IN THE RED RIVER VALLEY. SOME SLOW
CLEARING IS ADVANCING EAST...BUT HARD TO TELL VIA SATELLITE WITH
THESE TEMPS.
PREV DISCUSSION... /ISSUED 254 PM CST FRI NOV 23 2012/
SHORT TERM...
SNOW CHANCES SATURDAY AND TEMPERATURES THROUGHOUT THE PERIOD WILL
BE THE PRIMARY FORECAST PROBLEMS FOR THE SHORT TERM.
HIGH PRESSURE CONTINUES TO SLOWLY MOVE INTO THE CWA THIS
AFTERNOON AND WILL BE CENTERED OVER THE RED RIVER VALLEY THIS
EVENING. CLOUDS AND FLURRIES HAVE CONTINUED INTO THE
AFTERNOON. THINK THAT FLURRIES SHOULD END AND CLOUDS BEGIN TO
DECREASE AT LEAST OVER THE WESTERN AND CENTRAL AS WE LOSE DAYTIME
HEATING. THERE SHOULD BE A SHORT PERIOD WITH PARTLY CLOUDY SKIES
AND LIGHT WINDS PARTICULARLY OVER THE NORTHWESTERN CWA THIS
EVENING. TEMPS IN THAT AREAS SHOULD DROP LIKE A ROCK DURING THE
EVENING...PARTICULARLY AS TEMPS HAVE STAYED IN THE SINGLE DIGITS
THIS AFTERNOON. HOWEVER...A SFC TROUGH SHOULD STRENGTHEN ALONG THE
MT/ND BORDER AND BRING INCREASING CLOUDS AND SOUTHERLY WINDS.
THINK THAT AT LEAST THE WESTERN COUNTIES SHOULD SEE INCREASING
TEMPS AFTER MIDNIGHT TONIGHT. WENT NON-DIURNAL FOR HOURLIES
OVERNIGHT.
TOMORROW...A DECENT SHORTWAVE TROUGH WILL MOVE THROUGH MANITOBA
INTO ONTARIO. THE SFC TROUGH AXIS MOVES INTO THE RED RIVER VALLEY
DURING THE DAY. THERE SHOULD BE SOME DECENT WARM AIR ADVECTION AND
ISENTROPIC LIFT ALONG WITH THE SFC TROUGH AXIS. MOST OF THE MODELS
HAVE THE BEST QPF WITH THE MAIN UPPER LOW TO OUR NORTH...BUT MORE
RUNS ARE BRINGING SOME LIGHT PRECIP INTO OUR NORTHERN
COUNTIES...PARTICULARLY ON THE MINNESOTA SIDE. BUMPED UP POPS A
BIT FOR SATURDAY AFTERNOON...PUTTING SOME SNOW ACCUMULATIONS OF
UP TO AN INCH IN THE NORTHEASTERN COUNTIES. WITH WARM AIR
ADVECTION FOR MUCH OF THE DAY TEMPS SHOULD RETURN BRIEFLY TO THE
UPPER 20S TO LOW 30S EVEN WITH SOME CLOUD COVER.
THE UPPER TROUGH WILL DIG INTO ONTARIO AND MOVE OFF TO THE EAST BY
SUNDAY...WHICH WILL HELP BRING ANOTHER STRONG COLD FRONT INTO THE
AREA. TIMING OF THE FRONT IS A BIT UNCERTAIN. THE GFS BRINGS IT
DOWN INTO THE CWA THE FASTEST...WHILE THE NAM IS STILL IN THE FAR
NORTHERN CWA AT 12Z AND THE ECMWF IS IN BETWEEN. THE GFS SEEMS TO
BE AN OUTLIER SO AT THIS POINT THINK THE STRONG COLD AIR SURGE
WITH 850MB TEMPS IN THE TEENS BELOW ZERO WILL COME THROUGH DURING
THE DAY ON SUNDAY. WENT WITH FALLING TEMPS DURING SUNDAY AFTERNOON
WITH STRONG COLD AIR ADVECTION. ONLY A FEW FLURRIES ARE EXPECTED
WITH THE SYSTEM...BUT WILL HAVE TO WATCH IN CASE WIND GUSTS ALONG
THE FRONT BLOW SOME SNOW AROUND.
SUNDAY NIGHT SHOULD BE VERY COLD WITH TEMPS IN THE SINGLE DIGITS
UNDER SFC HIGH PRESSURE. MONDAY SHOULD BE FAIRLY QUIET AS A
SHORTWAVE TROUGH MISSES US JUST TO THE SOUTHWEST OF THE CWA. WITH
A COLD START AND NOT MUCH MIXING EARLY IN THE DAY...HIGHS SHOULD
REMAIN FAIRLY COLD IN THE TEENS TO LOW 20S...ALTHOUGH THE FAR
WESTERN COUNTIES SHOULD START TO SEE SOME WARM AIR ADVECTION LATE
IN THE DAY.
LONG TERM...MONDAY NIGHT THROUGH FRIDAY
MODELS ARE IN OVERALL DECENT AGREEMENT WITH MASS FIELDS, THOUGH
DISTINCT TIMING DIFFERENCES DO EXIST. UPPER FLOW AT THE START OF THE
FCST PD IS NW ACROSS THE UPPER MIDWEST...TURNING MORE ZONAL AFTER
MIDWEEK AS RIDGING ALONG THE WEST COAST DAMPENS. AN UPPER S/WV IS
EXPECTED TO DROP SEWD MON NIGHT BRINGING A LOW END CHC POPS TO THE
FAR NORTHERN ZNS MON NIGHT INTO TUE.
WITH THE UPPER FLOW TRANSITIONING TO A MORE ZONAL PATTERN....850
TEMPS MODERATE TO ABOVE ZERO BY MIDWEEK. EXPECT MAX TEMPS TO BE
SLIGHTLY BELOW NORMAL THROUGH THU BEFORE CLIMBING ABOVE FREEZING ON
FRI. WITH SFC HIGH PRESSURE AFTER TUE...KEPT THE FCST DRY THROUGH THE
REST OF THE WEEK.
AVIATION...
MVFR CIGS THIS AFTN WILL GIVE WAY TO VFR CONDS BY 00Z ALL SITES
EXCEPT FOR POSSIBLY KBJI. BRIEF PERIODS OF LIGHT SNOW SHOWERS HAVE
OCCURRED FROM THE VALLEY EAST THIS AFTN...HOWEVER EXPECT THIS
ACTIVITY TO DIMINISH DURING THE LATE AFTN. NW WINDS BETWEEN 10 AND
20 KTS WILL BECOME LIGHT AND VARIABLE AS HIGH PRESSURE CONT TO
BUILD ITO THE AREA. WINDS WILL TURN MORE SOUTHERLY BETWEEN 06Z AND
12Z SAT. A SCTD MID DECK SHOULD MOVE INTO THE VALLEY BY 12Z SAT
MORNING WHILE SLY WINDS INCREASE TO 10 TO 15 KTS BY THE END OF THE
FCST PD.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
RIDDLE/JR
AREA FORECAST DISCUSSION
NWS BISMARCK ND
829 PM CST FRI NOV 23 2012
.DISCUSSION...LATEST RADAR LOOP IS SHOWING A NICE BAND OF WARM
ADVECTION CLOUDS AND POSSIBLY SOME LIGHT SNOW TRACKING FROM
WESTERN INTO CENTRAL NORTH DAKOTA. GFS/NAM AND LATEST RAP ARE
INDICATING SOME VERY LIGHT QPF ACROSS THE NORTH. NO GROUND TRUTH
YET BUT LIGHTS IN WEATHER CAMERAS IN THE NORTHWEST LOOK A LITTLE
FUZZY INDICATING THERE MAY BE SOME LIGHT SNOW REACHING THE GROUND
AND CEILINGS HAVE LOWERED TO AROUND 5-7KFT IN THE NORTHWEST. WENT
AHEAD AND ADDED A SLIGHT CHANCE OF LIGHT SNOW ACROSS THE NORTHWEST
AND NORTH CENTRAL TONIGHT. SOME RETURNS EXTENDING INTO THE SOUTH
CENTRAL BUT MORE DRY AIR HERE AND BETTER MID LEVEL FORCING REMAINS
ACROSS THE NORTH.
OTHERWISE NO SIGNIFICANT CHANGES TO PREVIOUS FORECAST.
&&
.AVIATION...
VFR CONDITIONS WILL PREVAIL THROUGH THE 00Z TAF PERIOD. INCREASING
MID/UPPER LEVEL CLOUDS OVER NORTH DAKOTA AHEAD OF A WARM FRONT SET
TO MOVE INTO THE REGION LATER TONIGHT. DID BRING A PERIOD OF LIGHT
SNOW TO KMOT FROM 03-06 UTC WITH NO RESTRICTION TO VISIBILITY. WIND
SHIFT FROM THE SOUTH TO THE WEST FOLLOWING A COLD FRONTAL PASSAGE
LATE TOMORROW MORNING FOR ISN/DIK AND AFTERNOON FOR BIS/MOT/JMS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
TWH/LTH
AREA FORECAST DISCUSSION
NWS TAUNTON MA
1036 AM EST SAT NOV 24 2012
.SYNOPSIS...
COOLER AND BLUSTERY CONDITIONS ARE EXPECTED FOR THE REMAINDER OF
THE WEEKEND INTO EARLY NEXT WEEK. UNCERTAINTY REMAINS REGARDING
THE TRACK AND INTENSITY OF A POTENTIAL STORM NEXT TUESDAY AND
WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
1030 AM UPDATE... COLD FRONT WAS EXITING THE COASTAL WATERS. WEST
TO NORTHWEST WINDS WERE GUSTING AS HIGH AS 30 KT AT BOS AND 28 KT
AT CEF. AM EXPECTING WIND GUSTS TO REMAIN IN THE 20-25 KT RANGE
THIS AFTERNOON WITH A FEW HIGHER GUSTS. SURFACE WINDS MAY INCREASE
TOWARD EVENING IN WESTERN AREAS AS 850 MB WINDS STRENGTHEN.
DRIER AIR HAS FILTERED IN WITH DEWPOINTS ALREADY IN THE UPPER
TEENS AND LOWER 20S ACROSS THE REGION. AFTER INITIAL
SUNSHINE...SOME CUMULUS CLOUDS HAD ALREADY FORMED IN SOUTHWEST NH
AND WESTERN MA. THESE SHOULD SPREAD EAST ACROSS MUCH OF THE
INTERIOR BUT MAY NOT REACH THE SOUTHERN COASTAL AREAS. NO CHANGES
TO TEMPERATURES FROM PREVIOUS FORECAST...WITH HIGHS IN THE MID 40S
AND HOLDING RELATIVELY STEADY OR SLOWLY FALLING INTO THE UPPER
30S.
A PERSISTENT LAKE EFFECT SNOW SHOWER BAND WAS MOVING ACROSS NEW
YORK AND IT WAS FLURRYING AT ALBANY AS OF 10 AM. THE RAP MODEL
SHOWS FLURRIES MAKING IT INTO BERKSHIRE COUNTY AND SOUTHERN VT
BUT NOT ANY FURTHER WITH THE DOWNSLOPE DRYING FLOW. WILL KEEP AN
EYE ON THIS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/...
TONIGHT...
THE CONTINUED STRONG COLD AIR ADVECTION THRU THE MAJORITY OF THE
ATMOS COLUMN WILL KEEP LOW-LVLS WELL-MIXED TO H8. WIND GUSTS LIKELY
TO CONTINUE AT 25 TO 30 MPH /GALES OVER THE WATERS/. H85 W/NW FLOW
WILL BE SLIGHTLY STRONGER WITHIN THE TIGHTER PRES GRADIENT. LOOKING
AT H85 TEMPS AROUND -10 TO -12C. WHILE LOOKING TO REMAIN MOSTLY
CLEAR... WINDS WILL DIMINISH THE POTENTIAL FOR EFFECTIVE NOCTURNAL
COOLING. STILL...ANTICIPATING LOWS DOWN INTO THE LOW 20S WITH UPR
TEENS TO THE N/W INTERIOR NEW ENGLAND.
SUNDAY...
ANOTHER DAY OF CONTINUED BLUSTERY W/NW CONDITIONS WITH GUSTS 25 TO
30 MPH /POTENTIAL FOR CONTINUED GALES ACROSS THE WATERS/. VERY
LITTLE CHANGE IN THE AIRMASS WITH H85 TEMPS AROUND -8 TO -10C...SO
EXPECTING MAX TEMPS AROUND THE LOW 40S WITH PERHAPS INCREASING
CLOUDS LATE WITH WEAK WAVE ENERGY TRANSLATING THRU THE LONGWAVE
PATTERN /CLIPPER SYSTEM/.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
* COLDER...DRY WEATHER EXPECTED EARLY NEXT WEEK
* A STORM IS LIKELY TO AFFECT THE AREA MID WEEK
OVERVIEW AND MODEL PREFERENCES...
24/00Z MODEL GUIDANCE SUITE CONTINUES TO SHOW DECENT RUN-TO-RUN
CONSISTENCY AND GOOD AGREEMENT BETWEEN EACH OTHER THROUGH THE MID
TERM PERIOD. THEY HAVE ALSO BEGUN TO CONVERGE ON THE MID WEEK
SYSTEM THAT HAS BEEN DISCUSSED OF LATE. THIS IS NOT TO SAY ITS A
SLAM DUNK AT THIS POINT...BUT MODELS ARE NOW CLOSER TO ONE ANOTHER
IN THE LOW TRACK THAN PREVIOUS RUNS. ESSENTIALLY...WITH THE ZONAL
PROGRESSIVE FLOW ALOFT SUGGESTED IN ALL MODELS...THE GFS/ECMWF AND
RESPECTIVE ENSEMBLE MEANS NOW SUPPORT CYCLOGENESIS OFFSHORE OF THE
MID ATLANTIC STATES AND PUSHING THAT LOW FURTHER E THAN
/ESPECIALLY THE GFS AND GEFS/ GUIDANCE WAS PREVIOUSLY.
THEREFORE...THERE IS A BIT MORE SUPPORT FOR A COASTAL STORM RATHER
THAN ONE THAT PUSHES INLAND. THIS ALSO FAVORS A COOLER SOLN AS
WELL. THERE ARE STILL SIGNIFICANT TRACK DIFFERENCES THOUGH AS THE
GFS AND GEFS MEAN BRINGS THE LOW IN CLOSE PROXIMITY TO THE 40/70
BENCHMARK WHILE ECMWF/ECENS ARE MUCH FURTHER OFFSHORE WITH LITTLE
IMPACT ON SRN NEW ENGLAND. WILL BEGIN TO TREND GRIDS TOWARD THIS
COASTAL/COOL SOLN BUT WITH AN EYE TOWARD UNCERTAINTY IN FINAL
IMPACTS...WHICH WILL NEED TO BE MONITORED THROUGH THE WEEKEND AND
EARLY NEXT WEEK. COOL HIGH PRES BOOKEND THIS STORM EARLY THIS
COMING WEEK AND AGAIN LATE IN THE WEEK...AND GUIDANCE IS ACTUALLY
IN GOOD AGREEMENT HERE SO CONFIDENCE IS HIGHER IN COOL/DRY
CONDITIONS SURROUNDING THE STORM TEMPORALLY.
DETAILS...
SUN NIGHT INTO EARLY TUE...
STRONG UPPER LVL ZONAL JET WITH COOL NW FLOW AT THE SFC SUPPORT
TEMPS GENERALLY BELOW NORMAL AND OCCASIONALLY BLUSTERY CONDITIONS
THROUGH THIS PERIOD. MON...A FAST MOVING SHORTWAVE MAY ENHANCE THE
LOW LVL COLD ADVECTION AND USHER IN SOME LOW CLOUDS ASSOCIATED
WITH STRATO-CU DEVELOPMENT DOWNSTREAM OF THE GREAT LAKES. AT THIS
POINT...THE STRONG COLD ADVECTION SHOULD PREEMPT ANY PRECIP
DEVELOPMENT WITH THIS WAVE...SO DRY CONDITIONS ARE LIKELY TO
CONTINUE.
TUE AFTERNOON INTO WED NIGHT...
AS MENTIONED EARLIER CONFIDENCE IS /ALBEIT A LITTLE BIT/ HIGHER
THAN PREVIOUS FORECASTS REGARDING THE TRACK OF A LOW PRES DURING
THE MID WEEK TIMEFRAME. MOST GUIDANCE NOW SUPPORTS THE LOW TRACKS
OFFSHORE...A SUGGESTION THE THE ECENS/OPERATIONAL ECMWF HAS
SUPPORTED FOR SOME TIME NOW. THEREFORE...A COLDER SOLN IS
POSSIBLE...BUT GIVEN THE TRACK COULD BE CLOSE TO THE BENCHMARK
/THE GFS/CMC TRACK/ OR WELL OFFSHORE /THE ECMWF TRACK/ THE ACTUAL
EFFECTS ON SRN NEW ENGLAND REMAIN A BIT OF A QUESTION MARK. AT
THIS POINT THE MID LVL FLOW REGIMES ON BOTH OPERATIONAL MODELS DO
SO SOME POSSIBLE DEFORMATION...SO FORCING FOR PRECIP IS POSSIBLE
PARTICULARLY IN THE ERN HALF OF THE FA. AS MENTIONED EARLIER WILL
TREND GRIDS TOWARD THIS MORE OFFSHORE SOLN WITH THIS UPDATE...BUT
CARRY POPS ACROSS THE ENTIRE REGION AS THERE ARE STILL SOME
FACTORS THAT WILL HAVE TO BE IRONED OUT IN THE NEXT FEW DAYS. WILL
ALSO CONTINUE TO SHOW SOME SNOWFALL POSSIBLE PARTICULARLY W OF THE
I-495 AND I-95 CORRIDOR ALTHOUGH AMOUNTS WILL BE STRONGLY
CORRELATED TO THE FINAL TRACK...WHICH REMAINS IN QUESTION.
THU INTO EARLY WEEKEND...
WITH SOME ISSUES REGARDING THE TRACK OF THE SFC LOW AND ITS
ASSOCIATED WAVE THERE ARE STILL A FEW QUESTIONS REGARDING ANY FAST
MOVING SHORTWAVES DIVING OVER SRN NEW ENGLAND IN THE NW FLOW.
SUSPECT THAT MUCH OF THIS PERIOD WILL BE DRY AS MOST GUIDANCE
SUPPORTS HIGH PRES BUILDING IN ESPECIALLY FRI. WILL LEAN ON A DRY
COOL FORECAST GIVEN THE NW FLOW ATTM.
&&
.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT
MODERATE...30 PERCENT TO 60 PERCENT
HIGH...GREATER THAN 60 PERCENT
OVERVIEW...MODERATE TO HIGH CONFIDENCE.
VFR CONDITIONS IN THE WAKE OF A COLD FRONT THIS AFTERNOON.
BKN-OVC CUMULUS CLOUDS AT 4000-5000 FT IN WESTERN AND CENTRAL
PORTIONS THROUGH THIS AFTERNOON. W-NW WINDS GUSTING TO 20-30 KT.
AN ISOLATED FLURRY POSSIBLE IN THE NRN BERKSHIRES AND EXTREME SWRN
NH. VFR TONIGHT.
KBOS TAF...MODERATE TO HIGH CONFIDENCE.
VFR. GUSTS TO 20-30 KT THIS AFTERNOON INTO TONIGHT.
KBDL TAF...HIGH CONFIDENCE. VFR. W-NW WINDS WITH GUSTS AROUND
25 KT INTO THIS EVENING.
OUTLOOK...SUNDAY NIGHT THROUGH WEDNESDAY...
SUNDAY NIGHT THROUGH MONDAY...HIGH CONFIDENCE.
VFR. MAYBE SOME MVFR CIGS IN THE ERN SLOPES OF THE BERKSHIRES.
TUESDAY AND WEDNESDAY...LOW CONFIDENCE.
MVFR/IFR CONDITIONS POSSIBLE IN POTENTIAL
RA/SN/FZRA/SNPL...DEPENDENT ON THE TRACK OF LOW PRES.
&&
.MARINE...
MODERATE TO HIGH CONFIDENCE INTO SUNDAY...
GALE WARNINGS HOISTED IN EXPECTATION OF STRONG W/NWLY FLOW IN WAKE
OF THE COLD FRNT DEVELOPING BY MIDDAY WITH GUSTS AT OR EXCEEDING 34
KTS. WILL KEEP SMALL CRAFT ADVISORIES POSTED FOR THE INNER HARBORS
AND BAYS. DUE TO THE STRONG W/NW FLOW...SEAS WILL BUILD TO 8 TO
10 FEET ACROSS THE OUTER WATERS INTO THIS EVENING.
WINDS ALOFT INCREASE THIS EVENING AND TONIGHT. WILL BE EVALUATING
TO SEE WHETHER GALE WARNINGS NEED TO BE EXTENDED TO THE INNER
HARBORS AND BAYS.
OUTLOOK...SUNDAY NIGHT THROUGH WEDNESDAY...
MODERATE CONFIDENCE THROUGH THE PERIOD.
SEAS...
SEAS DROP BRIEFLY BELOW 5 FT ESPECIALLY NEAR SHORE WATERS MON.
HOWEVER...SWELL WILL HAVE LITTLE TIME TO SUBSIDE BELOW 5 FT
THROUGH THE PERIOD ON THE OUTER WATERS. SO EXPECT AFTER BRIEF
PERIOD OF DIMINISHING SEAS INTO MON THAT SWELL WILL ONCE AGAIN
BUILD IN ADVANCE OF LOW PRES TUE INTO WED. WITH SEAS OF 5-8 FT
POSSIBLE ONCE AGAIN BY MID WEEK.
WINDS...
SUN NIGHT INTO MON WINDS OF 20-25 KT ARE LIKELY. WINDS DIMINISH
OVER THE WATERS TUE AND TUE NIGHT. HOWEVER A COASTAL STORM MAY
BRING ANOTHER CHANCE FOR GALE FORCE WINDS /AT LEAST SMALL CRAFT
LEVEL/ BY WED.
OVERALL...VERY NARROW WINDOW FOR CONDITIONS BELOW SMALL CRAFT
THRESHOLDS MON NIGHT INTO EARLY TUE. OTHERWISE...WHETHER IT BE
SEAS OR WINDS...SMALL CRAFT ADVISORIES ARE LIKELY THROUGH MUCH OF
THE PERIOD. THERE IS ALSO THE POSSIBILITY OF SOME GALES BY WED
DEPENDING ON THE TRACK OF LOW PRES.
&&
.FIRE WEATHER...
MUCH COOLER AND DRIER AIR THIS AFTERNOON WITH W/NW WINDS GUSTING
UP TO 30 MPH. WHILE WE HAVE NOT SEEN A DECENT RAINFALL SINCE
NOVEMBER 13TH...AND STRONG WINDS ARE FORECAST...RELATIVE
HUMIDITIES ARE ANTICIPATED TO REMAIN AT OR ABOVE THE 30 PERCENT
THRESHOLD. THEREFORE WEATHER CONDITIONS WILL REMAIN JUST AT OR
ABOVE CRITERIA FOR ISSUING FIRE WEATHER HEADLINES.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...GALE WARNING UNTIL 10 AM EST SUNDAY FOR ANZ232>235-237-256.
SMALL CRAFT ADVISORY UNTIL 7 PM EST SUNDAY FOR ANZ230-231-236-
251.
GALE WARNING UNTIL 1 PM EST SUNDAY FOR ANZ250-254-255.
&&
$$
SYNOPSIS...DOODY/SIPPRELL
NEAR TERM...FIELD
SHORT TERM...SIPPRELL
LONG TERM...DOODY
AVIATION...FIELD/SIPPRELL/DOODY
MARINE...FIELD/SIPPRELL/DOODY
FIRE WEATHER...FIELD/SIPPRELL
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
947 AM CST SAT NOV 24 2012
.DISCUSSION...
930 AM CST
HAVE MADE SOME ADJUSTMENTS TO THE FORECAST TO HOLD ONTO CLOUDS
LONGER...PARTICULARLY ACROSS NORTHEAST IL AND NORTHWEST IN...AND
ACCORDINGLY HAVE LOWERED FORECAST HIGH TEMPS BY A COUPLE DEGREES
IN PLACES.
THE GOES WATER VAPOR LOOP THIS MORNING IS REFLECTING DRYING MOVING
EASTWARD OVER THE AREA...AND REGIONAL SOUNDINGS REFLECTED THAT IN
THE MID-LEVELS. HOWEVER...HEIGHT RISES AT 700 MB WERE NEUTRAL THIS
MORNING INDICATING LIMITED OVERALL SUPPRESSION...AS WAS 700 TO
850 MB TEMPERATURE ADVECTION /DVN AND GRB EVEN COOLED AT 700 MB/.
WITH PROFILERS ALSO INDICATING MORE OF A NORTHERLY FLOW IN THE
LOW-LEVELS...GENERAL CYCLONIC FLOW APPEARS TO BE HANGING ON
LONGER THAN INITIAL THOUGHT...ESPECIALLY ACROSS EASTERN AREAS.
THIS REGIME WILL NOT AID THE CLOUDS IN CLEARING THROUGH EARLY
AFTERNOON...EVEN WITH THE MOIST LAYER AT THE CLOUD HEIGHT
REMAINING SHALLOW /1000 FT OR LESS/ ON AMDAR SOUNDINGS AND THE GRB
RAOB THIS MORNING. ADAPTING AN AREA AMDAR SOUNDING IT WOULD SEEM
THAT SURFACE TEMPS IN THE MID 30S WOULD BE NEEDED TO MIX OUT SOME
OF THE CLOUD COVER...AND WITH NO WARMING HAPPENING UNDER THE HEART
OF THE CLOUDS AND MUCH LOWER STARTING TEMPERATURES THIS MORNING AT
THE PERIPHERY OF THE CLOUD SHIELD...DO NOT SEE THIS HAPPENING
ANYTIME SOON. SO OUTSIDE OF A COUPLE HOLES FROM THE WEAK TO
SUPPRESSION ALOFT...THE CLOUD SHIELD SHOULD ONLY OOZE ITS WAY
EAST THROUGH EARLY AFTERNOON THEN INCREASE IN SPEED WITH THE WARM
AIR ADVECTION PATTERN. EVEN AT 3 PM THOUGH...PARCEL TRAJECTORIES
OVER EASTERN AREAS ARE FROM CLOUD COVERED SOUTH CENTRAL WI AT
PRESENT. THE RAP 900 MB RH FORECAST SEEMS TO CAPTURE THE EVOLUTION
WELL...AND IS IN GOOD AGREEMENT WITH THE NARRE-TL CLOUD FORECAST.
SO HAVE COLLABORATED THESE IDEAS INTO THE CLOUD COVER FORECAST
AND KEPT TEMPERATURES CLIMBING AT ABOUT 1 DEGREE PER TWO HOURS
ACROSS THE EAST THROUGH EARLY AFTERNOON. OVERALL THIS TOOK HIGHS
DOWN 1 TO 3 DEGREES IN PLACES.
MTF
//PREV DISCUSSION...
352 AM CST
FOLLOWING AN ACTIVE HOLIDAY WEEK WITH DENSE FOG THANKSGIVING EVE
MORNING FOLLOWED BY NEAR RECORD WARMTH ON THANKSGIVING DAY... AND
THEN A JOLT BACK TO REALITY COURTESY OF A STRONG COLD FRONT ON
BLACK FRIDAY... THE COMING WEEKEND WILL BE RELATIVELY QUIET WITH
CHILLY DAYTIME HIGHS SATURDAY ONLY IN THE 30S... WITH MAX TEMPS
SUNDAY RETURNING TO AROUND SEASONAL NORMS.
AS DEEP SURFACE LOW PRESSURE OVER QUEBEC CONTINUES TO PUSH NE AWAY
FROM THE GREAT LAKES... RIDGING WILL BUILD QUICKLY INTO NRN IL/NW IN
THIS MORNING. THE STRENGTHENING ANTI-CYCLONIC FLOW COMBINED WITH
INCREASED SUBSIDENCE THROUGH THE MID LEVELS SHOULD DRY OUT STUBBORN
LINGERING SC FAIRLY QUICKLY FROM WEST TO EAST THROUGH THE MID
MORNING HOURS. DESPITE SUNSHINE THROUGH THE REMAINDER OF THE DAY...
TEMPS WILL ONLY RISE INTO THE MID 30S WITH COLD AIR AT 850 MB
HANGING AROUND UNTIL THE BETTER WARM AID ADVECTION (WAA) PATTERN
SETS UP ACROSS THE AREA THIS EVENING.
WITH LOW LEVEL WAA COMBINED WITH RISING HEIGHTS ALOFT EXPECT MIN
TEMPS TONIGHT TO BE REALIZED THIS EVENING WITH TEMPS THEN STEADYING
OUT BY LATE EVENING AND PROBABLY EVEN RISING A FEW DEGREES DURING
THE OVERNIGHT. EXPECT CLOUDS TO INCREASE AHEAD OF A FAIRLY POTENT
SECONDARY SHORTWAVE TROUGH DROPPING INTO THE UPPER GREAT LAKES
TONIGHT INTO EARLY SUNDAY. ANY FORCING OF CONSEQUENCE REMAINS NORTH
OF THE LOCAL AREA HOWEVER AND HENCE EXPECT PRECIP TO DO LIKEWISE.
SUNDAY SHAPING UP TO BE A FAIRLY TYPICAL LATE NOVEMBER DAY WITH
CLOUDS GIVING WAY TO SOME SUN AND TEMPS TOPPING OUT IN THE MID 40S.
A WEAK COLD FRONT ASSOCIATED WITH AFOREMENTIONED UPPER SHORTWAVE
TROUGH WILL SWEEP ACROSS THE REGION DURING THE AFTERNOON BUT SHOULD
RESULT IN LITTLE MORE THAN A WIND SHIFT AS COLDEST CORE OF AIR
BEHIND IT WILL REMAIN TO OUR NORTH.
MODELS CONTINUE TO TREND FARTHER SOUTH WITH LOW PRESSURE DEVELOPING
OVER THE SOUTHERN PLANS ON MONDAY AND THEN TRACKING ACROSS THE LOWER
MISSISSIPPI VALLEY MONDAY NIGHT AND ACROSS THE SOUTH ON TUES. WITH
THIS TREND BECOMING MORE PRONOUNCED... WILL CONTINUE PREVIOUS
FORECAST TREND OF LOWERING POPS ACROSS THE CWFA ANOTHER NOTCH FOR
THE MON NIGHT-TUES TIME PERIOD. SHOULD THIS MORE SOUTHERN TRACK
VERIFY... AT LEAST THE NORTHERN 2/3 OF THE CWFA IF NOT THE ENTIRE
AREA WILL PROBABLY SEE NO PRECIP AT ALL... HOWEVER GIVEN SOME
UNCERTAINTY REMAINING IN THE ENSEMBLE SPREAD... WOULD LIKE TO SEE
ANOTHER MODEL RUN BEFORE PULLING COMPLETELY.
A DRY NORTHWESTERLY FLOW ALOFT SETS UP FOR WED AND THURS WITH
BROAD HIGH PRESSURE DOMINATING AT THE SURFACE AND SEASONAL TEMPS.
THEN LEE SIDE CYCLOGENEIS DEVELOPS IN RESPONSE TO AN UPPER LEVEL
TROUGH MOVING INTO THE CENTRAL PLAINS LATER ON THURSDAY AND MOVES
INTO THE LOCAL AREA LATE THURSDAY NIGHT INTO FRIDAY. HAVE
INTRODUCED LOW POPS WITH THIS FEATURE AS DYNAMICS INITIALLY
APPEAR REASONABLY IMPRESSIVE HOWEVER AT DAYS 6-7 WOULD LIKE TO
SEE GREATER MODEL CONSISTENCY BEFORE INTRODUCING MENTION OF
ANYTHING MORE THAN A SLIGHT CHANCE OF PRECIP. THE AIR MASS IN
PLACE AT THE TIME WILL BE SUFFICIENTLY COLD ENOUGH TO SUPPORT A
MIX OF RAIN AND SNOW INITIALLY EARLY FRIDAY BEFORE INCREASING WAA
WARMS THE COLUMN TO AT OR ABOVE THE FREEZING MARK.
ED F
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* CEILINGS IN THE 2500-3000 FT RANGE THROUGH ABOUT 18Z...THEN
BECOMING SCATTERED.
* WEST TO NORTHWEST WIND 10 KT OR LESS GRADUALLY BECOMING MORE
SOUTHWEST TO WEST BY LATE AFTERNOON.
PAW
//DISCUSSION...UPDATED 16Z...
CLOUD DECK HAS BEEN SLOW TO ERODE FROM THE WEST THIS MORNING SO
HAVE SLOWED DOWN THE IMPROVEMENT BY A COUPLE HOURS. MAY HAVE TO
SLOW IT EVEN FURTHER.
PREVIOUS DISCUSSION FROM 12Z...
LOW PRESSURE CONTINUES TO DEPART THE REGION WITH AN AREA OF HIGH
PRESSURE SLOWLY BUILDING INTO THE WESTERN GREAT LAKES FROM THE
CENTRAL PLAINS. BETWEEN THE TWO SYSTEMS A STRATUS LAYER HAS
REMAINED ACROSS NORTHERN IL/NORTHWEST IN AIRFIELDS EARLY THIS
MORNING...AND WILL PERSIST THRU 16Z. THEN DRY WILL CONTINUE TO
ERODE THE OVC CIGS...THINNING THE STRATUS DECK TO A SCT DECK ARND
MID-MORNING. IN ADDITION WINDS WILL TURN W/SW BY MIDDAY/EARLY
AFTN. THIS WILL ALLOW ADDTL DRY AIR TO FILTER INTO THE
REGION...LIFTING THE BORDERLINE MVFR OR LOW END VFR CIGS TO ALL
VFR CONDS. WINDS WILL THEN SLOWLY TURN S BY THIS EVE...HOWEVER
REMAIN AT OR LESS THAN 10 KT. AFT 06Z SUN...THE GRADIENT BEGINS TO
RETURN AND GUIDANCE SUGGESTS THAT WINDS WILL BEGIN TO INCREASE
TOWARDS DAYBREAK SUN FROM THE S TO AROUND 10 TO 15 KT. OTHERWISE
VFR CONDS WILL PREVAIL WITH JUST SOME MID-DECK CLOUDS ARND 8KFT
AGL SLIDING OVERHEAD.
BEACHLER
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* HIGH CONFIDENCE IN WIND TREND.
* HIGH CONFIDENCE IN CEILING TREND...MEDIUM CONFIDENCE IN TIMING.
PAW
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT...VFR.
MONDAY...VFR. CHC OF LGT SN AND MVFR IN THE EVENING.
TUESDAY...CHC OF MVFR EARLY...TRENDING VFR LATE.
WEDNESDAY THROUGH THURSDAY...VFR.
FRIDAY...VFR. SLIGHT CHC LGT RA/SN AND PATCHY MVFR.
BEACHLER
&&
.MARINE...
258 AM CST
OCCASIONAL GALES CONTINUE ACROSS THE NORTHERN HALF OF LAKE MICHIGAN
EARLY THIS MORNING...HOWEVER THE FREQUENCY CONTINUES TO DIMINISH.
THUS IT APPEARS THE GALE WARNING WILL BE ALLOWED TO EXPIRE AT
ISSUANCE OF THE NEW GLF. WILL MENTION AN OCCASIONAL GALE FORCE GUST
TO 35 KT THROUGH DAYBREAK. THEN EXPECT WINDS TO STEADILY DIMINISH.
HIGH PRESSURE WILL BEGIN TO BUILD IN FROM THE WEST...WHICH WILL
ALLOW WINDS TO FURTHER DIMINISH AND BECOME WESTERLY THIS
AFTERNOON. WILL CONTINUE TO FEATURE THE SMALL CRAFT ADVISORY
THROUGH EARLY THIS AFTERNOON...POSSIBLY ENDING EARLIER FOR THE
ILLINOIS NEARSHORE WATERS. WINDS WILL CONTINUE TO DIMINISH
THROUGHOUT THE AFTERNOON AND EARLY EVENING...HOWEVER THE HIGH
PRESSURE WILL QUICKLY DRIFT SOUTHEAST OF THE REGION. THIS WILL
ALLOW ANOTHER TIGHT GRADIENT TO RETURN LATE TONIGHT WITH WINDS
INCREASING FROM THE W/SW TO 15-25 KT. THIS WILL ALLOW WAVES ACROSS
THE NORTHERN TIER OF LAKE MICHIGAN TO BUILD TONIGHT. THEN ANOTHER
BOUNDARY WILL SLIDE ACROSS THE LAKE SUNDAY THAT WILL ONCE AGAIN
ALLOW WINDS TO TURN NORTHWEST. WITH COLD AIR FLOWING OVER LAKE
MICHIGAN...WAVES SHOULD EASILY BUILD LATER IN THE WEEKEND. THEN
YET ANOTHER AREA OF HIGH PRESSURE APPEARS TO BUILD INTO THE REGION
EARLY IN THE UPCOMING WEEK...WHICH SHOULD ALLOW WINDS TO DIMINISH
MONDAY TO AROUND 10-20 KT BEFORE INCREASING AHEAD OF YET ANOTHER
WEAK LOW PRESSURE AND FRONTAL BOUNDARY.
CONFIDENCE...MEDIUM/LOW.
BEACHLER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 4 PM SATURDAY.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS CHICAGO/ROMEOVILLE IL
931 AM CST SAT NOV 24 2012
.DISCUSSION...
930 AM CST
HAVE MADE SOME ADJUSTMENTS TO THE FORECAST TO HOLD ONTO CLOUDS
LONGER...PARTICULARLY ACROSS NORTHEAST IL AND NORTHWEST IN...AND
ACCORDINGLY HAVE LOWERED FORECAST HIGH TEMPS BY A COUPLE DEGREES
IN PLACES.
THE GOES WATER VAPOR LOOP THIS MORNING IS REFLECTING DRYING MOVING
EASTWARD OVER THE AREA...AND REGIONAL SOUNDINGS REFLECTED THAT IN
THE MID-LEVELS. HOWEVER...HEIGHT RISES AT 700 MB WERE NEUTRAL THIS
MORNING INDICATING LIMITED OVERALL SUPPRESSION...AS WAS 700 TO
850 MB TEMPERATURE ADVECTION /DVN AND GRB EVEN COOLED AT 700 MB/.
WITH PROFILERS ALSO INDICATING MORE OF A NORTHERLY FLOW IN THE
LOW-LEVELS...GENERAL CYCLONIC FLOW APPEARS TO BE HANGING ON
LONGER THAN INITIAL THOUGHT...ESPECIALLY ACROSS EASTERN AREAS.
THIS REGIME WILL NOT AID THE CLOUDS IN CLEARING THROUGH EARLY
AFTERNOON...EVEN WITH THE MOIST LAYER AT THE CLOUD HEIGHT
REMAINING SHALLOW /1000 FT OR LESS/ ON AMDAR SOUNDINGS AND THE GRB
RAOB THIS MORNING. ADAPTING AN AREA AMDAR SOUNDING IT WOULD SEEM
THAT SURFACE TEMPS IN THE MID 30S WOULD BE NEEDED TO MIX OUT SOME
OF THE CLOUD COVER...AND WITH NO WARMING HAPPENING UNDER THE HEART
OF THE CLOUDS AND MUCH LOWER STARTING TEMPERATURES THIS MORNING AT
THE PERIPHERY OF THE CLOUD SHIELD...DO NOT SEE THIS HAPPENING
ANYTIME SOON. SO OUTSIDE OF A COUPLE HOLES FROM THE WEAK TO
SUPPRESSION ALOFT...THE CLOUD SHIELD SHOULD ONLY OOZE ITS WAY
EAST THROUGH EARLY AFTERNOON THEN INCREASE IN SPEED WITH THE WARM
AIR ADVECTION PATTERN. EVEN AT 3 PM THOUGH...PARCEL TRAJECTORIES
OVER EASTERN AREAS ARE FROM CLOUD COVERED SOUTH CENTRAL WI AT
PRESENT. THE RAP 900 MB RH FORECAST SEEMS TO CAPTURE THE EVOLUTION
WELL...AND IS IN GOOD AGREEMENT WITH THE NARRE-TL CLOUD FORECAST.
SO HAVE COLLABORATED THESE IDEAS INTO THE CLOUD COVER FORECAST
AND KEPT TEMPERATURES CLIMBING AT ABOUT 1 DEGREE PER TWO HOURS
ACROSS THE EAST THROUGH EARLY AFTERNOON. OVERALL THIS TOOK HIGHS
DOWN 1 TO 3 DEGREES IN PLACES.
MTF
&&
.PREV DISCUSSION...
352 AM CST
FOLLOWING AN ACTIVE HOLIDAY WEEK WITH DENSE FOG THANKSGIVING EVE
MORNING FOLLOWED BY NEAR RECORD WARMTH ON THANKSGIVING DAY... AND
THEN A JOLT BACK TO REALITY COURTESY OF A STRONG COLD FRONT ON
BLACK FRIDAY... THE COMING WEEKEND WILL BE RELATIVELY QUIET WITH
CHILLY DAYTIME HIGHS SATURDAY ONLY IN THE 30S... WITH MAX TEMPS
SUNDAY RETURNING TO AROUND SEASONAL NORMS.
AS DEEP SURFACE LOW PRESSURE OVER QUEBEC CONTINUES TO PUSH NE AWAY
FROM THE GREAT LAKES... RIDGING WILL BUILD QUICKLY INTO NRN IL/NW IN
THIS MORNING. THE STRENGTHENING ANTI-CYCLONIC FLOW COMBINED WITH
INCREASED SUBSIDENCE THROUGH THE MID LEVELS SHOULD DRY OUT STUBBORN
LINGERING SC FAIRLY QUICKLY FROM WEST TO EAST THROUGH THE MID
MORNING HOURS. DESPITE SUNSHINE THROUGH THE REMAINDER OF THE DAY...
TEMPS WILL ONLY RISE INTO THE MID 30S WITH COLD AIR AT 850 MB
HANGING AROUND UNTIL THE BETTER WARM AID ADVECTION (WAA) PATTERN
SETS UP ACROSS THE AREA THIS EVENING.
WITH LOW LEVEL WAA COMBINED WITH RISING HEIGHTS ALOFT EXPECT MIN
TEMPS TONIGHT TO BE REALIZED THIS EVENING WITH TEMPS THEN STEADYING
OUT BY LATE EVENING AND PROBABLY EVEN RISING A FEW DEGREES DURING
THE OVERNIGHT. EXPECT CLOUDS TO INCREASE AHEAD OF A FAIRLY POTENT
SECONDARY SHORTWAVE TROUGH DROPPING INTO THE UPPER GREAT LAKES
TONIGHT INTO EARLY SUNDAY. ANY FORCING OF CONSEQUENCE REMAINS NORTH
OF THE LOCAL AREA HOWEVER AND HENCE EXPECT PRECIP TO DO LIKEWISE.
SUNDAY SHAPING UP TO BE A FAIRLY TYPICAL LATE NOVEMBER DAY WITH
CLOUDS GIVING WAY TO SOME SUN AND TEMPS TOPPING OUT IN THE MID 40S.
A WEAK COLD FRONT ASSOCIATED WITH AFOREMENTIONED UPPER SHORTWAVE
TROUGH WILL SWEEP ACROSS THE REGION DURING THE AFTERNOON BUT SHOULD
RESULT IN LITTLE MORE THAN A WIND SHIFT AS COLDEST CORE OF AIR
BEHIND IT WILL REMAIN TO OUR NORTH.
MODELS CONTINUE TO TREND FARTHER SOUTH WITH LOW PRESSURE DEVELOPING
OVER THE SOUTHERN PLANS ON MONDAY AND THEN TRACKING ACROSS THE LOWER
MISSISSIPPI VALLEY MONDAY NIGHT AND ACROSS THE SOUTH ON TUES. WITH
THIS TREND BECOMING MORE PRONOUNCED... WILL CONTINUE PREVIOUS
FORECAST TREND OF LOWERING POPS ACROSS THE CWFA ANOTHER NOTCH FOR
THE MON NIGHT-TUES TIME PERIOD. SHOULD THIS MORE SOUTHERN TRACK
VERIFY... AT LEAST THE NORTHERN 2/3 OF THE CWFA IF NOT THE ENTIRE
AREA WILL PROBABLY SEE NO PRECIP AT ALL... HOWEVER GIVEN SOME
UNCERTAINTY REMAINING IN THE ENSEMBLE SPREAD... WOULD LIKE TO SEE
ANOTHER MODEL RUN BEFORE PULLING COMPLETELY.
A DRY NORTHWESTERLY FLOW ALOFT SETS UP FOR WED AND THURS WITH
BROAD HIGH PRESSURE DOMINATING AT THE SURFACE AND SEASONAL TEMPS.
THEN LEE SIDE CYCLOGENEIS DEVELOPS IN RESPONSE TO AN UPPER LEVEL
TROUGH MOVING INTO THE CENTRAL PLAINS LATER ON THURSDAY AND MOVES
INTO THE LOCAL AREA LATE THURSDAY NIGHT INTO FRIDAY. HAVE
INTRODUCED LOW POPS WITH THIS FEATURE AS DYNAMICS INITIALLY
APPEAR REASONABLY IMPRESSIVE HOWEVER AT DAYS 6-7 WOULD LIKE TO
SEE GREATER MODEL CONSISTENCY BEFORE INTRODUCING MENTION OF
ANYTHING MORE THAN A SLIGHT CHANCE OF PRECIP. THE AIR MASS IN
PLACE AT THE TIME WILL BE SUFFICIENTLY COLD ENOUGH TO SUPPORT A
MIX OF RAIN AND SNOW INITIALLY EARLY FRIDAY BEFORE INCREASING WAA
WARMS THE COLUMN TO AT OR ABOVE THE FREEZING MARK.
ED F
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* CEILINGS IN THE 2500-3000 FT RANGE THROUGH 16Z...THEN BECOMING
SCATTERED.
* NORTHWEST WINDS AROUND 10 KT BECOMING WEST BY MIDDAY AND
SOUTHWEST BY LATE AFTERNOON.
PAW
//DISCUSSION...UPDATED 12Z...
LOW PRESSURE CONTINUES TO DEPART THE REGION WITH AN AREA OF HIGH
PRESSURE SLOWLY BUILDING INTO THE WESTERN GREAT LAKES FROM THE
CENTRAL PLAINS. BETWEEN THE TWO SYSTEMS A STRATUS LAYER HAS
REMAINED ACROSS NORTHERN IL/NORTHWEST IN AIRFIELDS EARLY THIS
MORNING...AND WILL PERSIST THRU 16Z. THEN DRY WILL CONTINUE TO
ERODE THE OVC CIGS...THINNING THE STRATUS DECK TO A SCT DECK ARND
MID-MORNING. IN ADDITION WINDS WILL TURN W/SW BY MIDDAY/EARLY
AFTN. THIS WILL ALLOW ADDTL DRY AIR TO FILTER INTO THE
REGION...LIFTING THE BORDERLINE MVFR OR LOW END VFR CIGS TO ALL
VFR CONDS. WINDS WILL THEN SLOWLY TURN S BY THIS EVE...HOWEVER
REMAIN AT OR LESS THAN 10 KT. AFT 06Z SUN...THE GRADIENT BEGINS TO
RETURN AND GUIDANCE SUGGESTS THAT WINDS WILL BEGIN TO INCREASE
TOWARDS DAYBREAK SUN FROM THE S TO AROUND 10 TO 15 KT. OTHERWISE
VFR CONDS WILL PREVAIL WITH JUST SOME MID-DECK CLOUDS ARND 8KFT
AGL SLIDING OVERHEAD.
BEACHLER
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* HIGH CONFIDENCE IN WIND TREND.
* HIGH CONFIDENCE IN CEILING TREND...MEDIUM CONFIDENCE IN TIMING.
PAW
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT...VFR.
MONDAY...VFR. CHC OF LGT SN AND MVFR IN THE EVENING.
TUESDAY...CHC OF MVFR EARLY...TRENDING VFR LATE.
WEDNESDAY THROUGH THURSDAY...VFR.
FRIDAY...VFR. SLIGHT CHC LGT RA/SN AND PATCHY MVFR.
BEACHLER
&&
.MARINE...
258 AM CST
OCCASIONAL GALES CONTINUE ACROSS THE NORTHERN HALF OF LAKE MICHIGAN
EARLY THIS MORNING...HOWEVER THE FREQUENCY CONTINUES TO DIMINISH.
THUS IT APPEARS THE GALE WARNING WILL BE ALLOWED TO EXPIRE AT
ISSUANCE OF THE NEW GLF. WILL MENTION AN OCCASIONAL GALE FORCE GUST
TO 35 KT THROUGH DAYBREAK. THEN EXPECT WINDS TO STEADILY DIMINISH.
HIGH PRESSURE WILL BEGIN TO BUILD IN FROM THE WEST...WHICH WILL
ALLOW WINDS TO FURTHER DIMINISH AND BECOME WESTERLY THIS
AFTERNOON. WILL CONTINUE TO FEATURE THE SMALL CRAFT ADVISORY
THROUGH EARLY THIS AFTERNOON...POSSIBLY ENDING EARLIER FOR THE
ILLINOIS NEARSHORE WATERS. WINDS WILL CONTINUE TO DIMINISH
THROUGHOUT THE AFTERNOON AND EARLY EVENING...HOWEVER THE HIGH
PRESSURE WILL QUICKLY DRIFT SOUTHEAST OF THE REGION. THIS WILL
ALLOW ANOTHER TIGHT GRADIENT TO RETURN LATE TONIGHT WITH WINDS
INCREASING FROM THE W/SW TO 15-25 KT. THIS WILL ALLOW WAVES ACROSS
THE NORTHERN TIER OF LAKE MICHIGAN TO BUILD TONIGHT. THEN ANOTHER
BOUNDARY WILL SLIDE ACROSS THE LAKE SUNDAY THAT WILL ONCE AGAIN
ALLOW WINDS TO TURN NORTHWEST. WITH COLD AIR FLOWING OVER LAKE
MICHIGAN...WAVES SHOULD EASILY BUILD LATER IN THE WEEKEND. THEN
YET ANOTHER AREA OF HIGH PRESSURE APPEARS TO BUILD INTO THE REGION
EARLY IN THE UPCOMING WEEK...WHICH SHOULD ALLOW WINDS TO DIMINISH
MONDAY TO AROUND 10-20 KT BEFORE INCREASING AHEAD OF YET ANOTHER
WEAK LOW PRESSURE AND FRONTAL BOUNDARY.
CONFIDENCE...MEDIUM/LOW.
BEACHLER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 4 PM SATURDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
503 AM CST SAT NOV 24 2012
.DISCUSSION...
ISSUED 225 AM CST SAT NOV 24 2012
LATEST SURFACE MAP SHOWING HIGH PRESSURE RIDGE EXTENDING FROM
OKLAHOMA NORTHWARD INTO MINNESOTA. WIDESPREAD STRATOCUMULUS IN THE
CYCLONIC FLOW OVER THE GREAT LAKES HAS PUSHED SOUTHWARD TO ABOUT A
PONTIAC TO PARIS LINE AS OF 2 AM. LARGE SHIELD OF MID AND HIGH
CLOUDS ALSO DROPPING SOUTHEAST FROM THE NORTHERN AND CENTRAL PLAINS.
THE PRIMARY FORECAST CONCERN INVOLVES THE PRECIPITATION POTENTIAL
MONDAY AND MONDAY NIGHT...INCLUDING ANY WINTER PRECIP TYPES...AS A
STORM SYSTEM PASSES TO OUR SOUTH.
SHORT TERM...TODAY THROUGH MONDAY NIGHT...
LATEST RAP MODEL AND VAD WIND PROFILES AT 925 MB SUGGEST THE
LOWER CLOUDS SHOULD NOT MAKE MUCH FURTHER WESTWARD PROGRESS...AND
BEGIN TO PULL EASTWARD LATER THIS MORNING. HIGH CLOUDS STREAMING
IN FROM THE NORTHWEST WILL YIELD PARTLY TO MOSTLY SUNNY CONDITIONS
TODAY. TEMPERATURES EXPECTED TO REMAIN RATHER CHILLY TODAY WITH
MID TO UPPER 30S COMMON...AS THE RIDGE AXIS MOVES OVERHEAD.
RETURN FLOW EXPECTED TO BEGIN SETTING UP AROUND SUNSET.
TEMPERATURES ACROSS THE WESTERN CWA EXPECTED TO LEVEL OFF BY
MIDNIGHT...AND PERHAPS RISE A COUPLE DEGREES LATE. HIGHS ON SUNDAY
SHOULD BE ABOUT 10-15 DEGREES WARMER.
LARGE UPPER TROUGH OVER THE EASTERN CONUS TO BREAK DOWN THIS
WEEKEND AS SOME AMPLIFICATION TAKES PLACE ALONG THE WEST COAST.
FAST MOVING JET STREAK OF AROUND 75 KNOTS AT 500 MB WILL PUSH A
BOUNDARY ACROSS THE CWA ON SUNDAY...BUT CLOUDS WILL BE THE MAIN
EFFECT FROM IT. OF MORE CONCERN IS A STORM SYSTEM DEVELOPING ALONG
THE TEXAS/OKLAHOMA BORDER LATE SUNDAY NIGHT AND MONDAY. WHILE THE
EVENING MODELS ALL KEEP THE PARENT SURFACE LOW WELL TO OUR
SOUTH...MOISTURE WILL BE DRAWN NORTH AS A SHORTWAVE IN THE
NORTHERN JET STREAM MOVES INTO THE PLAINS. GFS/CANADIAN MODELS
DRAW THE PRECIPITATION AS FAR NORTH AS ABOUT THE I-72 CORRIDOR BY
MONDAY EVENING...WHILE THE NAM/ECMWF MODELS KEEP ALL THE PRECIP TO
OUR SOUTH. THESE LATTER MODELS MAY BE A LITTLE ON THE FASTER
SIDE...ESPECIALLY THE ECMWF...SO WILL LEAN MORE TOWARD THE SLOWER
SOLUTIONS. AS SUCH...WILL HAVE THE HIGHEST POPS ACROSS THE
SOUTHEAST CWA...ESPECIALLY MONDAY AFTERNOON AND NIGHT. FORECAST
SOUNDINGS INDICATE A RAIN TO SNOW TRANSITION MONDAY EVENING ACROSS
THE SOUTHEAST CWA AND LIGHT SNOW ELSEWHERE...BUT A PERSISTENT DRY
NORTHEAST FLOW WILL KEEP PRECIP TOTALS DOWN. HAVE KEPT AREAS
NORTHWEST OF THE ILLINOIS RIVER WITH MAINLY SLIGHT CHANCE
POPS...WHERE HIGH PRESSURE WILL BUILD IN TO THE AREA.
LONG TERM...TUESDAY THROUGH FRIDAY...
MAINLY QUIET CONDITIONS EXPECTED DURING THIS TIME FRAME. UPPER
RIDGING OVER THE WESTERN U.S. SHOULD TRANSITION TO MORE OF A ZONAL
FLOW AS THE WEEK PROGRESSES...WITH MODERATING TEMPERATURES. LONGER
RANGE MODELS PUSH A FAST MOVING SHORTWAVE THROUGH THE STATE LATE
THURSDAY NIGHT OR EARLY FRIDAY. THE GFS IS THE WETTER OF THE
MODELS WITH THIS FEATURE BUT MAINLY KEEPS THE PRECIPITATION JUST
TO OUR NORTH...SO WILL KEEP THE EXTENDED FORECAST DRY.
GEELHART
&&
.AVIATION...
ISSUED 503 AM CST SAT NOV 24 2012
A LARGE AREA OF MVFR CLOUDS IS AFFECTING BMI AND CMI THIS MORNING.
BASED ON SATELLITE TRENDS...APPEARS THIS CLOUD DECK WILL NOT GET
ANY FURTHER WEST THIS MORNING...THOUGH IT IS COMING CLOSE TO DEC
AND PIA. MODELS DO NOT HAVE A GOOD HANDLE ON THIS LOW LEVEL
MOISTURE AT THIS TIME...SO WILL TRY TO FORECAST CLEARING AT BMI
AND PIA BASED ON SHIFTING OF HIGH PRSS RIDGE...WHICH SHOULD BE
SOMETIME LATER THIS MORNING. SPI/PIA/DEC WILL REMAIN CLEAR THIS
MORNING. ALL SITES WILL ALSO SEE AN INCREASE...AND LOWERING...OF
MID CLOUDS THIS AFTERNOON...IN RESPONSE TO THE WAA THAT BEGINS TO
RETURN THIS AFTERNOON ONCE THE HIGH PRSS RIDGE MOVES EAST OF THE
AREA. ONCE THIS MOVES THROUGH...THE HIGH CIRRUS CLOUDS SHOULD BE
THE RULE FOR THE NIGHT. WINDS WILL BE LIGHT WEST-NORTHWESTERLY
THIS MORNING AND THEN BECOME SOUTH-SOUTHWESTERLY THIS AFTERNOON
AND THEN CONTINUE INTO THE NIGHT. WINDS SPEEDS WILL NOT INCREASE
TO AFTER 06Z LATE TONIGHT.
AUTEN
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
1032 AM EST SAT NOV 24 2012
.UPDATE...
LATEST RADAR AND SURFACE OBSERVATIONS SHOW LITTLE MORE THAN
FLURRIES ACROSS THE AREA THIS MORNING THANKS TO IMPRESSIVE DRY AIR
ENTRAINMENT. CEILINGS ARE HOVERING AROUND 2500 FT WITH VERY DRY
AIR ABOVE 5-6 KFT...SEVERELY LIMITING SNOW POTENTIAL. UPDATED
FORECAST TO REMOVE ALL POPS AND TO EXPAND FLURRIES IN THE
NORTHEAST. THIS RELATIVELY THIN LAYER OF STRATOCU HAS BEEN SLOW
TO ERODE TO OUR SOUTHWEST THOUGH AND MADE SOME ADJUSTMENTS TO SKY
COVER AS WELL. EXPECT CLOUDS AND FLURRIES WILL CONTINUE UNTIL LATE
THIS AFTERNOON WHEN THE FLOW BECOMES INCREASINGLY ANTICYCLONIC
WITH BUILDING MIDLEVEL HEIGHTS AND LARGE SCALE SUBSIDENCE. ALSO
SHAVED A DEGREE OR TWO OFF HIGH TEMPS OWING TO MORE PESSIMISTIC
CLOUD FORECAST.
&&
.PREV DISCUSSION... /ISSUED 341 AM EST SAT NOV 24 2012/
SHORT TERM...
FAILED LES RESPONSE ALG WRN PERIPHERY OF LK MI SO FAR OWING TO
DEGREE OF DRY ENTRAINMENT ONGOING OUT OF WI. MOST FVRBL LK SP FETCH
PRECONDITIONING 2 INTENSE BANDS ACRS NRN LWR STRETCHING SEWD INTO
THE THUMB. SOME INDICATION IN RECENT RADAR IMAGERY OF WK BANDING
DVLPG ALG A KMKG-KBIV LINE AND IF THAT INDEED DVLPS AS RUC SOLUTIONS
SUGGEST THAT CONTD SHALLOW BNDRY LYR VEERING SHLD ALLOW THAT TO SAG
SWD THROUGH MID MORNING. HWVR GIVEN THE DEARTH OF ADDNL MSTR ALOFT
WILL BACK POPS OFF CONSIDERABLY.
OTHERWISE CONTD QUITE COLD TDA W/LG AREA OF STRATO CU LOCKED IN
BENEATH FAIRLY SHARP LL INVERSION. FLW BACKS LT AFTN WHICH WILL
ERODE SWRN EDGE AND PROMOTE LIMITED INSOLATION BUT CONSIDERED TOO
LATE TO APPRECIABLE PROMOTE MORE OF A DIURNAL RESPONSE. GREATER CLRG
XPCD GOING INTO THIS EVENING AHD OF INCOMING HIGH CLD SHIELD
ASSOCD/W FAST MOVING DISTURBANCE OVR SWRN CANADA. LOSS OF DEEPER SC
UNDERNEATH ENVELOPING BUT THIN HIGH CLD SHIELD PERPLEXING GIVEN COLD
MOS GUIDANCE IN LIGHT OF SWRLY RTN FLW DVLPG ON BACKSIDE OF
DEPARTING RIDGE AXIS. THUS WILL ONLY MAKE SLIGHT ADJUSTMENTS FOR
TYPICAL LOCAL COLD SPOTS.
UPSTREAM SYS WILL DEAMPLIFY QUICKLY SEWD ON SUN. WAA AHD OF THIS FTR
AND PARTIAL SUN WILL YIELD A BTR DIURNAL RESPONSE W/ANTICIPATED
GREATER MIXING AND GAVE A +1 BUMP HIGHER.
LONG TERM...MONDAY THROUGH FRIDAY
MAIN FOCUS REMAINS ON DWINDLING CHANCES FOR SNOW WITH SYSTEM NOW
PROGGED TO TRACK THROUGH THE TN/OH VALLEYS LATE MONDAY AFTERNOON
THROUGH TUESDAY MORNING. 12/00Z GFS/GEFS/GEM ITERATIONS HAVE ALL
TRENDED TOWARD THE LESS AMPLIFIED AND THEREFORE FARTHER SOUTH
SOLUTION OF THE ECMWF WITH A SFC LOW TRACK FROM THE SOUTHERN PLAINS
EAST THROUGH THE TN VALLEY. THIS SOUTHERLY TRACK WOULD RESULT IN
DRY/COLD CONDITIONS LOCALLY WITH SFC HIGH PRESSURE BUILDING INTO THE
SOUTHERN GREAT LAKES. HOWEVER...WOULD NOT BE SURPRISED TO SEE MODELS
TREND BACK A LITTLE TO THE NORTH AND MORE AMPLIFIED WITH THIS
POSITIVE PV ANOMALY AS IT DROPS SOUTHEAST INTO THE MIDWEST. INITIAL
PROGRESSIVE POSITIVE TILT AND CONFLUENCE ACROSS THE LAKES WILL KEEP
IT FROM MAKING IT TOO FAR NORTH BUT CANNOT RULE OUT NORTHERN FRINGE
OF PCPN SHIELD CLIPPING OUR AREA. GUIDANCE OFTEN WEAKENS OR LOSES A
STORM IN THE 4-5 DAY PERIOD ONLY TO LATCH BACK ONTO A STRONGER
SOLUTION WITHIN 72 HOURS AS WAVE FINALLY REACHES OUR RADIOSONDE
NETWORK. HAVE BEEN BURNT BY THIS SEVERAL TIMES SO OPTED TO RETAIN
LOWER CHANCE POPS MAINLY MONDAY NIGHT...HIGHEST SOUTH. THIS WILL
NEED TO BE MONITORED CLOSELY GIVEN PROSPECTS FOR A NARROW SWATH OF
ACCUMULATING SNOW ON THE NORTHERN FLANK OF THIS SYSTEM.
ATTENTION FOR THE MID TO LATE WEEK PERIOD WILL TURN TO TEMPERATURES
AND CLOUD COVER. TOUGH FORECAST AS AREA LIKELY TO BE NEAR A FRONTAL
BOUNDARY ON THE SOUTHWESTERN FRINGE OF A RETREATING POLAR
JET...ESPECIALLY BY THURSDAY AND FRIDAY. A DEVELOPING NEGATIVE
NAO/AO WILL HELP MAINTAIN NORTH ATLANTIC/EASTERN CANADA
BLOCKING...WHILE -PNA AND NORTHEAST PACIFIC NEGATIVE HEIGHT ANOMALY
ALLOW RIDGING/WARMTH TO OVERSPREAD THE PLAINS/MIDWEST. WE`LL BE IN
BETWEEN MAKING IT A DIFFICULT FORECAST. GIVEN THE UNCERTAINTIES
OPTED TO LOAD AND GO WITH THE 00Z ALLBLEND WHICH DOESN`T LOOK TOO
BAD AT THIS POINT WITH TEMPS TRENDING UP TO NEAR NORMAL BY
THURSDAY/FRIDAY. CLOUDS WITH ANY MOISTURE STARVED (LOW AMPLITUDE)
SHORTWAVES IN WNW FLOW WILL ALSO IMPACT TEMPS...ESPECIALLY LATE
THURSDAY INTO FRIDAY PER A ECMWF/GFS/GEFS COMPROMISE. GUIDANCE ALSO
PRINTING OUT SOME LIGHT QPF WITH THIS WAVE BUT WILL HOLD OFF ADDING
ANY POPS GIVEN TIMING DIFFERENCES AND LACK OF MOISTURE/FORCING WITH
SHEARED WAVE(S).
AVIATION...
MVFR CONDS THIS MORNING WILL GRADUALLY IMPROVE INTO THIS AFTN
W/CONTD LL DRY ENTRAINMENT. SIG SHSN AT KSBN LOOKING MORE AND MORE
DOUBTFUL AND WILL MOST LIKELY BE DROPPED W/12Z ISSUANCE AS DRY AIR
CLEARLY WINNING OUT SO FAR.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS EVENING FOR LMZ043-046.
&&
$$
SHORT TERM...T
LONG TERM...STEINWEDEL
AVIATION...T
UPDATE...AGD
AREA FORECAST DISCUSSION
NWS DULUTH MN
637 AM CST SAT NOV 24 2012
.AVIATION.../12Z TAF ISSUANCE/
COLD NWLY FLOW WILL RESULT IN OCCASIONAL -SHSN AND IFR/MVFR
CIGS....MAINLY AROUND KBRD AND KHYR THIS MORNING. A RIDGE OF HIGH
PRESSURE WILL ALLOW FOR A BRIEF PERIOD OF CLEARING AS IT
TRANSLATES ACROSS THE REGION TODAY. HOWEVER...THE NEXT LOW
PRESSURE SYSTEM WILL QUICKLY DROP OUT OF CANADA AND INTO NORTHWEST
MINNESOTA THIS AFTERNOON. THE LOW WILL SPREAD SNOW SHOWERS WITH LOWERING
CEILINGS/VSBYS ACROSS THE FORECAST AREA THROUGH THE LATE
AFTERNOON AND OVERNIGHT HOURS. THE LOWEST CIGS AND GREATEST
SNOWFALL ACCUMULATION WILL BE ACROSS THE BORDERLAND AND INTO THE
ARROWHEAD REGION...INCLUDING THE KINL AND KHIB TERMINALS.
&&
.PREV DISCUSSION... /ISSUED 402 AM CST SAT NOV 24 2012/
SHORT TERM...TODAY THROUGH SUNDAY.
AT 330 AM...A VARIETY OF CONDITIONS WERE FOUND ACROSS THE
NORTHLAND. THERE WAS A LARGE AREA OF LOW CLOUDS ACROSS NW WI WITH
SOME SNOW SHOWERS. A CHECK OF WEBCAMS IN THE HURLEY AREA INDICATED
LITTLE SNOW ACTIVITY BUT LIKELY SOME SNOW SHOWERS OR FLURRIES.
THERE WAS ANOTHER AREA OF LOW CLOUDS ACROSS WESTERN AREAS OF THE
CWA WITH SOME SNOW SHOWERS AND FLURRIES AS WELL. CLEAR SKIES WERE
FOUND IN A NW TO SE AREA IN BETWEEN. TEMPERATURES RANGED FROM THE
TEENS IN CLOUDY AREAS TO THE SINGLE DIGITS ABOVE AND BELOW ZERO IN
THE CLEAR AREAS.
A STRENGTHENING SHORTWAVE AND SURFACE LOW PRESSURE SYSTEM NOW
MOVING INTO SASKATCHEWAN AND MONTANA WILL AFFECT THE WEATHER
ACROSS THE REGION STARTING THIS AFTERNOON AND CONTINUING INTO
SUNDAY. SKIES WILL BE PARTLY SUNNY FOR MOST AREAS THIS
MORNING...BUT CLOUDS WILL QUICKLY INCREASE FROM THE WEST DURING
THE DAY. A COMBINATION OF FAVORABLE JET DYNAMICS...Q-VECTOR
CONVERGENCE AND FGEN WILL PRODUCE AN INCREASE IN SNOW STARTING
THIS AFTERNOON AND CONTINUING INTO TONIGHT. THE HRRR AND 4KM WRF
SEEM TO HAVE A GOOD HANDLE ON THE EVOLUTION OF THIS SYSTEM. WILL
INCREASE POPS CONSIDERABLY ACROSS THE BOARD...WITH CATEGORICAL
POPS ACROSS THE NORTH AND LIKELY FOR MOST AREAS LATER TODAY AND
THIS EVENING. CURRENT THINKING IS THAT THERE WILL BE WIDESPREAD 1
TO 3 INCH AMOUNTS...WITH 2 TO 4 INCHES ACROSS MUCH OF NORTHERN MN.
COULD ALSO BE SOME HIGHER AMOUNTS ACROSS THE NORTH SHORE OF LAKE
SUPERIOR...AS SOUTHWEST WINDS LEND SOME OROGRAPHIC LIFT ALONG THE
NORTH SHORE. MAY NEED TO RAISE AMOUNTS THERE IN LATER FORECASTS.
DRIER AIR WILL MOVE IN BEHIND THE SYSTEM TONIGHT AND INTO
SUNDAY...WITH GUSTY WEST TO NORTHWEST WINDS BECOMING THE MAIN
STORY FOR THE NORTHLAND ON SUNDAY. COULD STILL BE SOME LINGERING
SNOW SHOWERS...ESPECIALLY ACROSS THE NORTH...AND LAKE EFFECT SNOW
SHOWERS SHOULD DEVELOP FOR THE SOUTH SHORE.
LONG TERM...SUNDAY NIGHT THROUGH SATURDAY.
NW FLOW WILL BRING A CONTINUED CAA REGIME THROUGH THE WEEKEND.
MODELS ARE IN GOOD AGREEMENT THAT H85 TEMPS FALL INTO THE NEGATIVE
UPPER TEENS TO AROUND NEGATIVE 20 C EARLY MONDAY MORNING. HAVE
LOWERED TEMPS SUNDAY NIGHT AND MONDAY TO ACCOUNT FOR THIS COLD AIR.
THE NW TRAJECTORIES AND COLD H85 TEMPS WILL BRING AN OPPORTUNITY FOR
LK EFFECT SNOW ALONG THE SOUTH SHORE OF LK SUPERIOR SUNDAY NIGHT
INTO MONDAY WHERE LIGHT SNOW ACCUMULATION WILL BE POSSIBLE ALONG THE
GOGEBIC RANGE. LATEST NAM BUFR SOUNDINGS SHOW THE STEEP LAPSE RATES
ASSOCIATED WITH THE COLD AIR...AND A SHALLOW LAYER OF
MOISTURE...REMAINS OVER THE ARROWHEAD ZONES THROUGH SUNDAY NIGHT
WHERE FLURRIES OR VERY LIGHT SHSN MAY LINGER.
LONG TERM MODELS CONTINUE TO SHOW ANOTHER SHORT WAVE DROPS OUT OF
CANADA AND SWEEPS OVER THE NORTHLAND MID-WEEK. HAVE KEPT SMALL POPS
IN THE NRN ZONES TUESDAY.
&&
.POINT TEMPS/POPS...
DLH 24 16 25 9 / 50 70 10 0
INL 25 14 20 8 / 80 70 10 10
BRD 26 17 25 7 / 20 30 10 0
HYR 27 17 29 10 / 20 60 10 0
ASX 28 20 31 16 / 30 70 10 20
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
SHORT TERM...DAP
LONG TERM....GRANING
AVIATION...GRANING
AREA FORECAST DISCUSSION
NWS DULUTH MN
402 AM CST SAT NOV 24 2012
.SHORT TERM...TODAY THROUGH SUNDAY.
AT 330 AM...A VARIETY OF CONDITIONS WERE FOUND ACROSS THE
NORTHLAND. THERE WAS A LARGE AREA OF LOW CLOUDS ACROSS NW WI WITH
SOME SNOW SHOWERS. A CHECK OF WEBCAMS IN THE HURLEY AREA INDICATED
LITTLE SNOW ACTIVITY BUT LIKELY SOME SNOW SHOWERS OR FLURRIES.
THERE WAS ANOTHER AREA OF LOW CLOUDS ACROSS WESTERN AREAS OF THE
CWA WITH SOME SNOW SHOWERS AND FLURRIES AS WELL. CLEAR SKIES WERE
FOUND IN A NW TO SE AREA IN BETWEEN. TEMPERATURES RANGED FROM THE
TEENS IN CLOUDY AREAS TO THE SINGLE DIGITS ABOVE AND BELOW ZERO IN
THE CLEAR AREAS.
A STRENGTHENING SHORTWAVE AND SURFACE LOW PRESSURE SYSTEM NOW
MOVING INTO SASKATCHEWAN AND MONTANA WILL AFFECT THE WEATHER
ACROSS THE REGION STARTING THIS AFTERNOON AND CONTINUING INTO
SUNDAY. SKIES WILL BE PARTLY SUNNY FOR MOST AREAS THIS
MORNING...BUT CLOUDS WILL QUICKLY INCREASE FROM THE WEST DURING
THE DAY. A COMBINATION OF FAVORABLE JET DYNAMICS...Q-VECTOR
CONVERGENCE AND FGEN WILL PRODUCE AN INCREASE IN SNOW STARTING
THIS AFTERNOON AND CONTINUING INTO TONIGHT. THE HRRR AND 4KM WRF
SEEM TO HAVE A GOOD HANDLE ON THE EVOLUTION OF THIS SYSTEM. WILL
INCREASE POPS CONSIDERABLY ACROSS THE BOARD...WITH CATEGORICAL
POPS ACROSS THE NORTH AND LIKELY FOR MOST AREAS LATER TODAY AND
THIS EVENING. CURRENT THINKING IS THAT THERE WILL BE WIDESPREAD 1
TO 3 INCH AMOUNTS...WITH 2 TO 4 INCHES ACROSS MUCH OF NORTHERN MN.
COULD ALSO BE SOME HIGHER AMOUNTS ACROSS THE NORTH SHORE OF LAKE
SUPERIOR...AS SOUTHWEST WINDS LEND SOME OROGRAPHIC LIFT ALONG THE
NORTH SHORE. MAY NEED TO RAISE AMOUNTS THERE IN LATER FORECASTS.
DRIER AIR WILL MOVE IN BEHIND THE SYSTEM TONIGHT AND INTO
SUNDAY...WITH GUSTY WEST TO NORTHWEST WINDS BECOMING THE MAIN
STORY FOR THE NORTHLAND ON SUNDAY. COULD STILL BE SOME LINGERING
SNOW SHOWERS...ESPECIALLY ACROSS THE NORTH...AND LAKE EFFECT SNOW
SHOWERS SHOULD DEVELOP FOR THE SOUTH SHORE.
.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY.
NW FLOW WILL BRING A CONTINUED CAA REGIME THROUGH THE WEEKEND.
MODELS ARE IN GOOD AGREEMENT THAT H85 TEMPS FALL INTO THE NEGATIVE
UPPER TEENS TO AROUND NEGATIVE 20 C EARLY MONDAY MORNING. HAVE
LOWERED TEMPS SUNDAY NIGHT AND MONDAY TO ACCOUNT FOR THIS COLD AIR.
THE NW TRAJECTORIES AND COLD H85 TEMPS WILL BRING AN OPPORTUNITY FOR
LK EFFECT SNOW ALONG THE SOUTH SHORE OF LK SUPERIOR SUNDAY NIGHT
INTO MONDAY WHERE LIGHT SNOW ACCUMULATION WILL BE POSSIBLE ALONG THE
GOGEBIC RANGE. LATEST NAM BUFR SOUNDINGS SHOW THE STEEP LAPSE RATES
ASSOCIATED WITH THE COLD AIR...AND A SHALLOW LAYER OF
MOISTURE...REMAINS OVER THE ARROWHEAD ZONES THROUGH SUNDAY NIGHT
WHERE FLURRIES OR VERY LIGHT SHSN MAY LINGER.
LONG TERM MODELS CONTINUE TO SHOW ANOTHER SHORT WAVE DROPS OUT OF
CANADA AND SWEEPS OVER THE NORTHLAND MID-WEEK. HAVE KEPT SMALL POPS
IN THE NRN ZONES TUESDAY.
&&
.AVIATION.../06Z TAF ISSUANCE/
COLD NWLY FLOW ALOFT WILL ALLOW INTERMITTENT BKN IFR/MVFR CIGS
AROUND BRD/HIB/DLH TONIGHT WITH PERIODS OF LIGHT SNOW POSSIBLE.
HYR WILL REMAIN UNDER LOW-END MVFR CIGS TONIGHT WITH FLURRIES. INL
SHOULD REMAIN SKC WITH MUCH DRIER AIR TO THE NORTH. HIGH PRESSURE
WILL MOVE ACROSS THE REGION TONIGHT AND AID IN THE CLEARING
SOMEWHAT...BUT BE QUICKLY OVERTAKEN BY THE NEXT LOW PRESSURE
SYSTEM MOVING IN FROM THE WEST BY EARLY FRI AFTERNOON. WILL SEE
-SN DEVELOP AND CIGS DROP BY 20Z FRIDAY AROUND BRD/INL...AND
SHORTLY AFTER AT HIB AND DLH. BEST CHC OF ACCUMULATING SNOW WILL
BE ACROSS THE NORTH...WITH REDUCED IFR VSBYS POSSIBLE AS WELL
EARLY FRI EVENING. WINDS SHOULD REMAIN LESS THAN 15 KTS.
&&
.POINT TEMPS/POPS...
DLH 24 16 25 9 / 50 70 10 0
INL 25 14 20 8 / 80 70 10 10
BRD 26 17 25 7 / 20 30 10 0
HYR 27 17 29 10 / 20 60 10 0
ASX 28 20 31 16 / 30 70 10 20
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
SHORT TERM...DAP
LONG TERM....GRANING
AVIATION...TENTINGER
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
700 AM EST SAT NOV 24 2012
.SYNOPSIS...
STRONG NORTHWEST WINDS AND COLD AIR CROSSING THE GREAT LAKES WILL
GENERATE LAKE EFFECT SNOW SHOWERS ACROSS THE WESTERN MOUNTAINS
INTO TONIGHT. FAST WEST-NORTHWEST FLOW ALOFT WILL BRING A COUPLE
OF WEAK LOW PRESSURE SYSTEMS ACROSS THE GREAT LAKES ON SUNDAY AND
AGAIN MONDAY. A WEAK TROUGH OF LOW PRESSURE WILL FORM OVER THE
LOWER MISSISSIPPI VALLEY ON MONDAY. AN AREA OF LOW PRESSURE COULD
DEVELOP AND SLIDE PRECIPITATION INTO THE REGION FROM THE
SOUTHWEST FOR MONDAY NIGHT INTO TUESDAY NIGHT.
&&
.NEAR TERM /UNTIL 5 PM THIS AFTERNOON/...
LAKE EFFECT SNOW ADVISORY CONTINUES FOR WARREN AND MCKEAN
COUNTIES. A SLIGHT VEERING OF THE MEAN WIND HAS OCCURRED IN THE
LOWER LAYERS THIS MORNING. THIS HAS CHANGED THE CHARACTER OF THE
LAKE EFFECT SNOWS FROM THE EARLIER BROKEN CLUMP OF SHSN INTO MORE-
LINEAR BANDS. HOWEVER...THERE IS LITTLE ORGANIZATION TO THEM AT
1130Z. THERE IS A CONNECTION FROM LAKE HURON JUST SOUTH OF KBUF
AND INTO KELM. A SECOND WIDE/BROAD AREA OF CONVERGENCE TO THE
SOUTH OF THAT FROM KJHW INTO THE NRN MTS. THE BETTER-ALIGNED FLOW
IN THE LOW LEVELS WILL TRY TO MAKE THE PRECIP MORE BANDED THROUGH
THE DAY. BUT STRONG VERTICAL SPEED SHEAR AND SOME MEAGER DAYTIME
HEATING/MIXING WILL TRY TO COUNTERACT THAT TENDENCY. THUS...THE
CONVECTION WILL BE MORE CELLULAR THAN TRUE BANDS FOR MOST OF THE
AREA. THAT SAID...THE HIGH RES MODELS DO PLAY UP A HURON
CONNECTION WHICH COULD STRING MOD SNOW INTO THE CENTRAL MTS OR
EVEN THE POCONOS THIS AFTN. STILL...LITTLE ACCUMS ARE POSSIBLE OFF
THE ALLEGHENY PLATEAU AS TEMPS RISE INTO THE U30S/L40S AS YOU MOVE
OFF THE HIGHLANDS INTO THE SERN COS. THE SUBSIDENCE INVERSION
REMAIN BELOW 7KFT AT KBFD ALL DAY PER THE RUC FCST SOUNDINGS. THE
QPF REMAINS MEAGER WITH SREF AND DETERMINISTIC MODELS ALL MAKING
BETWEEN A TENTH AND TWO TENTHS OF AN INCH OF LIQUID TODAY. SLR/S
RUN GENERALLY 15:1 FOR THE DAY...BUT COULD BE 20:1 IN THE ADVY
AREA AS THE TOP OF THE CLOUDS APPEAR TO STAY IN THE GOOD DENDRITIC
GROWTH ZONE. THUS...WILL CONTINUE THE ADVY IN PLACE. HOWEVER...LOW
LEVEL AIR IS VERY DRY AND CIGS HIGHER THAN WHAT WOULD NORMALLY BE
EXPECTED FOR HEAVY SNOW. THIS AND THE TRANSIENT NATURE OF THE SHSN
TODAY WILL LIMIT THE ACCUMS...AND NO EXPANSION OF THE ADVY IS
NECESSARY. WINDS WILL MAKE IT FEEL VERY RAW...ESPECIALLY WITH
RESPECT TO THE RECENT MILD WEATHER WE HAVE EXPERIENCED.
&&
.SHORT TERM /5 PM THIS AFTERNOON THROUGH MONDAY/...
THE NW FLOW CONTINUES INTO THE EVENING AND EARLY TONIGHT.
HOWEVER...THE 8H TEMPS DO START TO TURN UPWARD AFTER MIDNIGHT. THE
WINDS IN THE LOW LAYERS WILL BACK TO A MORE-SWRLY FLOW AS WELL.
THIS SHOULD DWINDLE THE SHSN...BUT SOME MAY LINGER INTO SUNDAY.
THE REAL ACCUMS SHOULD BE OVER BY MIDNIGHT. THE TOTALS BY THE END
OF THE EVENT WILL STRUGGLE TO MEET ADVY NUMBERS EXCEPT IN THE FAR
NWRN PART OF THE ADVY AREA...PLACES CLOSEST TO THE LAKE...DUE TO
THE SHORT FETCH EXPECTED FOR MUCH OF THE EVENT.
FLOW ALOFT REMAINS VERY FAST AND NWRLY ON SUNDAY. A CLIPPER-LIKE
SHORTWAVE DROPS ACROSS THE LAKES ON SUNDAY AND WILL MAKE SOME SHSN
IN THE NRN MTS AT THE NOSE OF SOME SLIGHT WAA. BUT THE GLANCING
BLOW IS HARDLY WORTH ANY MORE OF A MENTION. A NEW SHOT OF COLD AIR
MOVES DOWN FROM THE NW LATE MONDAY...BUT ANY MSTR ASSOCIATED WITH
IT SHOULD GET DRIED UP...AND PROBABLY NOT ARRIVE AFTER THIS SHORT
TERM PERIOD.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
MODELS STILL HAVE SOME DIFFERENCES TO THE DEVELOPMENT OF A SYSTEM
WHICH WILL LIKELY IMPACT THE REGION MON NITE INTO TUESDAY. WHILE
THE 00Z ECMWF IS MORE GFS-LIKE NOW...THE OVERALL CONFIDENCE IN THE
MED RANGE FORECAST HAS GROWN ONLY A SLIGHT BIT. A WEAK INVERTED
TROUGH SHOULD DRAW MOISTURE NE FROM THE LOWER MS VALLEY MONDAY
NIGHT AND DEEPEN A LITTLE LOW OVER THE SRN APP MTS MONDAY
NIGHT/TUES. A GOOD DEAL OF QPF IS GENERATED TO THE NORTH OF THE
TRACK OF THIS WEAK SFC LOW BACK INTO THE COLD AIR OVER PA. THE EC
AND NAM SHOWS A WEAKER/FASTER LOW AND SHORTER TIME FRAME FOR
PRECIP OVER C PA. HAVE NUDGED THE FORECAST FOR MON NITE-TUES NITE
TOWARD THE CONGEALING CONSENSUS. THIS WILL PRETTY MUCH KEEP THE
FORECAST A 30-50 PCT CHANCE OF PRECIP IN THAT TIME FRAME AND MAKE
IT MORE SNOW P-TYPE THAN RAIN...SINCE A GENERALLY COLD SOLUTION IS
MORE LIKELY WITH THE SFC LOW TRACK/TROUGH TO THE S OF THE AREA.
NO CHANGES TO FCST FROM WED ONWARD.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
GUSTY WEST TO NORTHWEST WINDS WILL PERSIST TODAY...AND BRING LAKE
EFFECT CLOUDS /STRATOCU/ TO MOST AIRFIELDS...THOUGH CIGS AFTER
SUNRISE SHOULD GENERALLY BE VFR EXCEPT AT BFD AND JST WHERE THEY
WILL REMAIN MVFR FOR SEVERAL HOURS THIS MORNING. FLURRIES AND ISOLD
SNOW SHOWERS WILL FLOW OFF THE LAKES AS WELL...BUT ANY HEAVY
ENOUGH TO CAUSE VSBY REDUCTIONS BELOW VFR SHOULD BE CONFINED TO BFD
AND JST.
IMPROVING CONDITIONS ARE EXPECTED THIS AFTERNOON THROUGH SUNDAY
AS WINDS SHIFT MORE TO THE WEST THIS AFTERNOON AND EVENING AND
THEN TO THE SW ON SUNDAY.
OUTLOOK... SUN...SHSN/MVFR CIGS NW MTNS...VFR ELSEWHERE.
MON- WED...VFR TO MVFR. CHC OF PCPN TUE-WED.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
LAKE EFFECT SNOW ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR
PAZ004-005.
&&
$$
SYNOPSIS...DANGELO
NEAR TERM...DANGELO
SHORT TERM...DANGELO
LONG TERM...DANGELO/TYBURSKI
AVIATION...GARTNER/MARTIN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
648 AM EST SAT NOV 24 2012
.SYNOPSIS...
STRONG NORTHWEST WINDS AND COLD AIR CROSSING THE GREAT LAKES WILL
GENERATE LAKE EFFECT SNOW SHOWERS ACROSS THE WESTERN MOUNTAINS
INTO TONIGHT. FAST WEST-NORTHWEST FLOW ALOFT WILL BRING A COUPLE
OF WEAK LOW PRESSURE SYSTEMS ACROSS THE GREAT LAKES ON SUNDAY AND
AGAIN MONDAY. A WEAK TROUGH OF LOW PRESSURE WILL FORM OVER THE
LOWER MISSISSIPPI VALLEY ON MONDAY. AN AREA OF LOW PRESSURE COULD
DEVELOP AND SLIDE PRECIPITATION INTO THE REGION FROM THE
SOUTHWEST FOR MONDAY NIGHT INTO TUESDAY NIGHT.
&&
.NEAR TERM /UNTIL 5 PM THIS AFTERNOON/...
LAKE EFFECT SNOW ADVISORY CONTINUES FOR WARREN AND MCKEAN
COUNTIES. A SLIGHT VEERING OF THE MEAN WIND HAS OCCURRED IN THE
LOWER LAYERS THIS MORNING. THIS HAS CHANGED THE CHARACTER OF THE
LAKE EFFECT SNOWS FROM THE EARLIER BROKEN CLUMP OF SHSN INTO MORE-
LINEAR BANDS. HOWEVER...THERE IS LITTLE ORGANIZATION TO THEM AT
1130Z. THERE IS A CONNECTION FROM LAKE HURON JUST SOUTH OF KBUF
AND INTO KELM. A SECOND WIDE/BROAD AREA OF CONVERGENCE TO THE
SOUTH OF THAT FROM KJHW INTO THE NRN MTS. THE BETTER-ALIGNED FLOW
IN THE LOW LEVELS WILL TRY TO MAKE THE PRECIP MORE BANDED THROUGH
THE DAY. BUT STRONG VERTICAL SPEED SHEAR AND SOME MEAGER DAYTIME
HEATING/MIXING WILL TRY TO COUNTERACT THAT TENDENCY. THUS...THE
CONVECTION WILL BE MORE CELLULAR THAN TRUE BANDS FOR MOST OF THE
AREA. THAT SAID...THE HIGH RES MODELS DO PLAY UP A HURON
CONNECTION WHICH COULD STRING MOD SNOW INTO THE CENTRAL MTS OR
EVEN THE POCONOS THIS AFTN. STILL...LITTLE ACCUMS ARE POSSIBLE OFF
THE ALLEGHENY PLATEAU AS TEMPS RISE INTO THE U30S/L40S AS YOU MOVE
OFF THE HIGHLANDS INTO THE SERN COS. THE SUBSIDENCE INVERSION
REMAIN BELOW 7KFT AT KBFD ALL DAY PER THE RUC FCST SOUNDINGS. THE
QPF REMAINS MEAGER WITH SREF AND DETERMINISTIC MODELS ALL MAKING
BETWEEN A TENTH AND TWO TENTHS OF AN INCH OF LIQUID TODAY. SLR/S
RUN GENERALLY 15:1 FOR THE DAY...BUT COULD BE 20:1 IN THE ADVY
AREA AS THE TOP OF THE CLOUDS APPEAR TO STAY IN THE GOOD DENDRITIC
GROWTH ZONE. THUS...WILL CONTINUE THE ADVY IN PLACE. HOWEVER...LOW
LEVEL AIR IS VERY DRY AND CIGS HIGHER THAN WHAT WOULD NORMALLY BE
EXPECTED FOR HEAVY SNOW. THIS AND THE TRANSIENT NATURE OF THE SHSN
TODAY WILL LIMIT THE ACCUMS...AND NO EXPANSION OF THE ADVY IS
NECESSARY. WINDS WILL MAKE IT FEEL VERY RAW...ESPECIALLY WITH
RESPECT TO THE RECENT MILD WEATHER WE HAVE EXPERIENCED.
&&
.SHORT TERM /5 PM THIS AFTERNOON THROUGH MONDAY/...
THE NW FLOW CONTINUES INTO THE EVENING AND EARLY TONIGHT.
HOWEVER...THE 8H TEMPS DO START TO TURN UPWARD AFTER MIDNIGHT. THE
WINDS IN THE LOW LAYERS WILL BACK TO A MORE-SWRLY FLOW AS WELL.
THIS SHOULD DWINDLE THE SHSN...BUT SOME MAY LINGER INTO SUNDAY.
THE REAL ACCUMS SHOULD BE OVER BY MIDNIGHT. THE TOTALS BY THE END
OF THE EVENT WILL STRUGGLE TO MEET ADVY NUMBERS EXCEPT IN THE FAR
NWRN PART OF THE ADVY AREA...PLACES CLOSEST TO THE LAKE...DUE TO
THE SHORT FETCH EXPECTED FOR MUCH OF THE EVENT.
FLOW ALOFT REMAINS VERY FAST AND NWRLY ON SUNDAY. A CLIPPER-LIKE
SHORTWAVE DROPS ACROSS THE LAKES ON SUNDAY AND WILL MAKE SOME SHSN
IN THE NRN MTS AT THE NOSE OF SOME SLIGHT WAA. BUT THE GLANCING
BLOW IS HARDLY WORTH ANY MORE OF A MENTION. A NEW SHOT OF COLD AIR
MOVES DOWN FROM THE NW LATE MONDAY...BUT ANY MSTR ASSOCIATED WITH
IT SHOULD GET DRIED UP...AND PROBABLY NOT ARRIVE AFTER THIS SHORT
TERM PERIOD.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
MODELS STILL HAVE SOME DIFFERENCES TO THE DEVELOPMENT OF A SYSTEM
WHICH WILL LIKELY IMPACT THE REGION MON NITE INTO TUESDAY. WHILE
THE 00Z ECMWF IS MORE GFS-LIKE NOW...THE OVERALL CONFIDENCE IN THE
MED RANGE FORECAST HAS GROWN ONLY A SLIGHT BIT. A WEAK INVERTED
TROUGH SHOULD DRAW MOISTURE NE FROM THE LOWER MS VALLEY MONDAY
NIGHT AND DEEPEN A LITTLE LOW OVER THE SRN APP MTS MONDAY
NIGHT/TUES. A GOOD DEAL OF QPF IS GENERATED TO THE NORTH OF THE
TRACK OF THIS WEAK SFC LOW BACK INTO THE COLD AIR OVER PA. THE EC
AND NAM SHOWS A WEAKER/FASTER LOW AND SHORTER TIME FRAME FOR
PRECIP OVER C PA. HAVE NUDGED THE FORECAST FOR MON NITE-TUES NITE
TOWARD THE CONGEALING CONSENSUS. THIS WILL PRETTY MUCH KEEP THE
FORECAST A 30-50 PCT CHANCE OF PRECIP IN THAT TIME FRAME AND MAKE
IT MORE SNOW P-TYPE THAN RAIN...SINCE A GENERALLY COLD SOLUTION IS
MORE LIKELY WITH THE SFC LOW TRACK/TROUGH TO THE S OF THE AREA.
NO CHANGES TO FCST FROM WED ONWARD.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
GUSTY NORTHWEST WINDS WILL PERSIST TODAY...AND BRING LAKE EFFECT
CLOUDS /STRATOCU/ TO MOST AIRFIELDS...AND SCT SNOW SHOWERS MAINLY
TO THE HIER ELEVATIONS SITES. VSBY/CIG REDUCTIONS LIKELY AT BFD
AND JST.
BFD AND JST WILL BOUNCE BACK AND FORTH BETWEEN VFR AND MVFR EARLY
THIS MORNING AS ROUNDS OF MAINLY LIGHT SNOW SHOWERS MOVE ACROSS.
LATEST RADAR AND 11-3.9 SATELLITE IMAGERY SHOW LATEST ROUND OF
THICKER CLOUDS REACHING LOWER SUSQ VALLEY...MDT/LNS...ATTM WITH
EVEN AN ISOLD FLURRY PSBL...BUT NO REDUCTIONS EXPECTED. UNV AND
AOO WILL SEE A FEW SNOW SHOWERS AND BRIEF MVFR CIGS AT TIMES.
IMPROVING CONDITIONS ARE EXPECTED FOR SUNDAY AS WINDS SHIFT MORE
TO THE WEST AND SW.
OUTLOOK...
SUN...SHSN/MVFR CIGS NW MTNS...VFR ELSEWHERE.
MON-WED...VFR TO MVFR. CHC OF PCPN TUE-WED.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
LAKE EFFECT SNOW ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR
PAZ004-005.
&&
$$
SYNOPSIS...DANGELO
NEAR TERM...DANGELO
SHORT TERM...DANGELO
LONG TERM...DANGELO/TYBURSKI
AVIATION...GARTNER/MARTIN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
502 AM EST SAT NOV 24 2012
.SYNOPSIS...
STRONG NORTHWEST WINDS AND COLD AIR CROSSING THE GREAT LAKES WILL
GENERATE LAKE EFFECT SNOW SHOWERS ACROSS THE WESTERN MOUNTAINS
INTO TONIGHT. FAST WEST-NORTHWEST FLOW ALOFT WILL BRING A COUPLE
OF WEAK LOW PRESSURE SYSTEMS ACROSS THE GREAT LAKES ON SUNDAY AND
AGAIN MONDAY. A WEAK TROUGH OF LOW PRESSURE WILL FORM OVER THE
LOWER MISSISSIPPI VALLEY ON MONDAY. AN AREA OF LOW PRESSURE COULD
DEVELOP AND SLIDE PRECIPITATION INTO THE REGION FROM THE
SOUTHWEST FOR MONDAY NIGHT INTO TUESDAY NIGHT.
&&
.NEAR TERM /UNTIL 4 PM THIS AFTERNOON/...
LAKE EFFECT SNOW ADVISORY CONTINUES FOR WARREN AND MCKEAN
COUNTIES. A SLIGHT VEERING OF THE MEAN WIND HAS OCCURRED IN THE
LOWER LAYERS THIS MORNING. THIS HAS CHANGED THE CHARACTER OF THE
LAKE EFFECT SNOWS FROM THE EARLIER BROKEN CLUMP OF SHSN INTO MORE-
LINEAR BANDS. HOWEVER...THERE IS LITTLE ORGANIZATION TO THEM AT
09Z. THERE IS THE BEGINNING OF A CONNECTION FROM LAKE HURON
STARTING TO GO THROUGH KBUF WITH A SECOND WIDE/BROAD AREA OF
CONVERGENCE TO THE SOUTH OF THAT INTO THE NRN MTS. THE BETTER-
ALIGNED FLOW IN THE LOW LEVELS WILL HELP TO MAKE THE PRECIP MORE
BANDED THROUGH THE DAY. BUT STRONG VERTICAL SPEED SHEAR AND MEAGER
DAYTIME HEATING/MIXING WILL TRY TO COUNTERACT THAT TENDENCY.
THUS...THE CONVECTION WILL BE MORE CELLULAR THAN TRUE BANDS FOR
MOST OF THE AREA. THAT SAID...THE HIGH RES MODELS DO PLAY UP A
HURON CONNECTION WHICH COULD STRING MOD SNOW INTO THE CENTRAL MTS
OR EVEN THE POCONOS THIS AFTN. STILL...LITTLE ACCUMS ARE POSSIBLE
OFF THE ALLEGHENY PLATEAU AS TEMPS RISE INTO THE U30S/L40S AS YOU
MOVE OFF THE HIGHLANDS INTO THE SERN COS. THE SUBSIDENCE INVERSION
REMAIN BELOW 7KFT AT KBFD ALL DAY PER THE RUC FCST SOUNDINGS. THE
QPF REMAINS MEAGER WITH SREF AND DETERMINISTIC MODELS ALL MAKING
BETWEEN A TENTH AND TWO TENTHS OF AN INCH OF LIQUID TODAY. SLR/S
RUN GENERALLY 15:1 FOR THE DAY...BUT COULD BE 20:1 IN THE ADVY
AREA AS THE TOP OF THE CLOUDS APPEAR TO STAY IN THE GOOD DENDRITIC
GROWTH ZONE. THUS...WILL CONTINUE THE ADVY IN PLACE. HOWEVER...LOW
LEVEL AIR IS VERY DRY AND CIGS HIGHER THAN WHAT WOULD NORMALLY BE
EXPECTED FOR HEAVY SNOW. THIS AND THE TRANSIENT NATURE OF THE SHSN
TODAY WILL LIMIT THE ACCUMS...AND NO EXPANSION OF THE ADVY IS
NECESSARY. WINDS WILL MAKE IT FEEL VERY RAW...ESPECIALLY WITH
RESPECT TO THE RECENT MILD WEATHER WE HAVE EXPERIENCED.
&&
.SHORT TERM /4 PM THIS AFTERNOON THROUGH MONDAY/...
THE NW FLOW CONTINUES INTO THE EVENING AND EARLY TONIGHT.
HOWEVER...THE 8H TEMPS DO START TO TURN UPWARD AFTER MIDNIGHT. THE
WINDS IN THE LOW LAYERS WILL BACK TO A MORE-SWRLY FLOW AS WELL.
THIS SHOULD DWINDLE THE SHSN...BUT SOME MAY LINGER INTO SUNDAY.
THE REAL ACCUMS SHOULD BE OVER BY MIDNIGHT. THE TOTALS BY THE END
OF THE EVENT WILL STRUGGLE TO MEET ADVY NUMBERS EXCEPT IN THE FAR
NWRN PART OF THE ADVY AREA...PLACES CLOSEST TO THE LAKE...DUE TO
THE SHORT FETCH EXPECTED FOR MUCH OF THE EVENT.
FLOW ALOFT REMAINS VERY FAST AND NWRLY ON SUNDAY. A CLIPPER-LIKE
SHORTWAVE DROPS ACROSS THE LAKES ON SUNDAY AND WILL MAKE SOME SHSN
IN THE NRN MTS AT THE NOSE OF SOME SLIGHT WAA. BUT THE GLANCING
BLOW IS HARDLY WORTH ANY MORE OF A MENTION. A NEW SHOT OF COLD AIR
MOVES DOWN FROM THE NW LATE MONDAY...BUT ANY MSTR ASSOCIATED WITH
IT SHOULD GET DRIED UP...AND PROBABLY NOT ARRIVE AFTER THIS SHORT
TERM PERIOD.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
MODELS STILL HAVE SOME DIFFERENCES TO THE DEVELOPMENT OF A SYSTEM
WHICH WILL LIKELY IMPACT THE REGION MON NITE INTO TUESDAY. WHILE
THE 00Z ECMWF IS MORE GFS-LIKE NOW...THE OVERALL CONFIDENCE IN THE
MED RANGE FORECAST HAS GROWN ONLY A SLIGHT BIT. A WEAK INVERTED
TROUGH SHOULD DRAW MOISTURE NE FROM THE LOWER MS VALLEY MONDAY
NIGHT AND DEEPEN A LITTLE LOW OVER THE SRN APP MTS MONDAY
NIGHT/TUES. A GOOD DEAL OF QPF IS GENERATED TO THE NORTH OF THE
TRACK OF THIS WEAK SFC LOW BACK INTO THE COLD AIR OVER PA. THE EC
AND NAM SHOWS A WEAKER/FASTER LOW AND SHORTER TIME FRAME FOR
PRECIP OVER C PA. WILL STICK WITH GOING FCST WITHOUT MUCH CHANGE
IN FORECASTER CONFIDENCE. THIS WILL KEEP THE FORECAST A 30-50 PCT
CHANCE OF PRECIP FROM MON NIGHT INTO TUESDAY NIGHT...AND CHC RA OR
SN WORDING...BUT A GENERALLY COLD SOLUTION IS MORE LIKELY WITH THE
SFC LOW TRACK/TROUGH TO THE S OF THE AREA.
&&
.AVIATION /09Z SATURDAY THROUGH WEDNESDAY/...
GUSTY NORTHWEST WINDS WILL PERSIST TODAY...AND BRING LAKE EFFECT
CLOUDS /STRATOCU/ TO MOST AIRFIELDS...AND SCT SNOW SHOWERS MAINLY
TO THE HIER ELEVATIONS SITES. VSBY/CIG REDUCTIONS LIKELY AT BFD
AND JST.
BFD AND JST WILL BOUNCE BACK AND FORTH BETWEEN VFR AND MVFR EARLY
THIS MORNING AS ROUNDS OF MAINLY LIGHT SNOW SHOWERS MOVE ACROSS.
LATEST RADAR AND 11-3.9 SATELLITE IMAGERY SHOW LATEST ROUND OF
THICKER CLOUDS REACHING LOWER SUSQ VALLEY...MDT/LNS...ATTM WITH
EVEN AN ISOLD FLURRY PSBL...BUT NO REDUCTIONS EXPECTED. UNV AND
AOO WILL SEE A FEW SNOW SHOWERS AND BRIEF MVFR CIGS AT TIMES.
IMPROVING CONDITIONS ARE EXPECTED FOR SUNDAY AS WINDS SHIFT MORE
TO THE WEST AND SW.
OUTLOOK...
SUN...SHSN/MVFR CIGS NW MTNS...VFR ELSEWHERE.
MON-WED...VFR TO MVFR. CHC OF PCPN TUE-WED.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
LAKE EFFECT SNOW ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR
PAZ004-005.
&&
$$
SYNOPSIS...DANGELO
NEAR TERM...DANGELO
SHORT TERM...DANGELO
LONG TERM...DANGELO/TYBURSKI
AVIATION...GARTNER/MARTIN
AREA FORECAST DISCUSSION
NWS TAUNTON MA
436 PM EST SAT NOV 24 2012
.SYNOPSIS...
COOL AND BLUSTERY CONDITIONS ARE EXPECTED FOR THE REMAINDER OF
THE WEEKEND INTO EARLY NEXT WEEK. UNCERTAINTY REMAINS REGARDING
THE TRACK AND INTENSITY OF A STORM TUESDAY AND WEDNESDAY. MUCH
COLDER WEATHER IS EXPECTED BEHIND THE STORM LATE NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
430 PM UPDATE... WINDS HAVE INCREASED LATE THIS AFTERNOON AS THE
MIXING DEPTH GETS TO NEAR 850 MB. A GUST TO 44 KTS JUST OCCURRED
AT WORCESTER AT 4 PM... WITH 32 KTS WAS REPORTED AT ORANGE MA AND
33 KTS AT PITTSFIELD AT 3 PM. THE NORTHWEST PRESSURE GRADIENT WILL
CONTINUE TO TIGHTEN UP THIS EVENING AND OVERNIGHT IN THE WAKE OF
AN UPPER LEVEL TROUGH SWINGING ACROSS NORTHERN NEW ENGLAND. WINDS
AT 3000-5000 FT OFF THE GROUND ARE FORECAST TO INCREASE TO 40-45
KNOTS OVERNIGHT. IT IS A TRICKY CALL FOR THE WINDS TONIGHT. BUFKIT
SHOWS THAT DESPITE THE COLD AIR ADVECTION...THE WINDS DIMINISH TO
15 KT OVER MOST OF THE INTERIOR AS THE TEMPERATURE DROPS AND THE
MIXING LEVEL IS NOT AS DEEP. A MAJOR EXCEPTION IS ALONG THE
COAST...EVERYWHERE FROM CAPE ANN TO CAPE COD AND ON THE RI
COAST...WHERE IT SHOULD REMAIN GUSTING TO 25 TO 30 KTS OVERNIGHT.
FOR THE MOST PART...LAKE EFFECT SNOW SHOWERS HAVE BEEN CONFINED TO
THE BERKSHIRES. HOWEVER...A LIGHT SPRINKLE WAS REPORTED AT 3 PM IN
NASHUA NH... SO SOME OF THE PRECIPITATION IS HITTING THE GROUND.
CANNOT RULE OUT A FLAKE OF SNOW MAINLY WEST OF THE CONNECTICUT
RIVER THIS EVENING BUT ACTIVITY SHOULD DIMINISH WITH NIGHTFALL.
THE RAP MODEL SHOWS NO PRECIPITATION AFTER 04Z.
LOWS MAINLY IN THE UPPER TEENS TO MID 20S EXCEPT NEAR 30 ALONG THE
IMMEDIATE SOUTH COAST.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
SUNDAY...
SHOULD BE RATHER SIMILAR TO TODAY. SUNSHINE SHOULD GIVE WAY TO A
FAST MOVING BATCH OF MID LEVEL CLOUDINESS IN THE AFTERNOON LEADING
TO PARTLY TO MOSTLY CLOUDY SKIES. USED A 50-50 BLEND OF GFS AND
NAM FOR SKY GRIDS SINCE THEY DIFFERED ON THE TIMING OF THESE CLOUDS.
IT WILL AGAIN BECOME WINDY WITH GUSTS TO 20 TO 30 KTS FROM MID
MORNING THROUGH MID AFTERNOON AS THE MIXING INCREASES. WINDS
SHOULD DIMINISH LATE IN THE AFTERNOON. HIGHS MAINLY IN THE 40S.
SUNDAY NIGHT...
BECOMING MOSTLY CLEAR WITH LIGHT WINDS AND LOWS 20-30.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
* COLDER...DRY WEATHER EXPECTED EARLY NEXT WEEK
* A STORM IS LIKELY TO AFFECT THE AREA MID WEEK
* COLDER WEATHER EXPECTED LATE NEXT WEEK
24/12Z MODELS ARE STARTING TO SHOW SOME CONSISTENCY THROUGHOUT THE
LONG TERM PORTION OF THE FORECAST. THERE IS STILL PLENTY OF
UNCERTAINTY REGARDING THE MID WEEK STORM...THOUGH THE 06Z GFS/00Z
ECMWF/12Z GFS ALL HAVE SIMILAR SOLUTIONS WITH LOW PRESSURE MOVING
OFF THE MID ATLANTIC COAST AND TRAVELING JUST SOUTH OF THE 40/70
BENCHMARK AND BRINGING SNOW TO MUCH OF THE AREA WITH A FOCUS ON THE
SOUTHERN PORTIONS OF SOUTHERN NEW ENGLAND. HOWEVER...THE 12Z NAM
/AN OUTLIER AT THIS POINT/ SIMPLY HAS HIGH PRESSURE OVER THE REGION
AND NO INDICATION OF PRECIP AT ALL. WILL TREND TOWARD A
ECMWF/GFS/HPC SOLUTION... HOWEVER...KEEPING IN MIND ALL THE FLIP
FLOPPING AND UNCERTAINTY WILL ONLY TREND TOWARD IT.
ASIDE FROM THE STORM...THE WEATHER IS FAIRLY QUIET BOTH EARLY AND
LATE NEXT WEEK WITH NORTHWESTERLY FLOW BRINGING COLDER TEMPERATURES.
MONDAY...STRONG NORTHWESTERLY FLOW WILL CONTINUE TO KEEP TEMPS
SLIGHTLY BELOW NORMAL. HIGH PRESSURE BUILDS IN KEEPING MOSTLY CLEAR
SKIES THROUGH THE DAY AND INTO THE EVENING.
TUESDAY INTO WEDNESDAY...GIVEN THE NUMEROUS SOLUTIONS OVER THE LAST
SEVERAL DAYS AM STILL HESITANT TO MAKE A RUN FOR A SINGLE SOLUTION.
THAT SAID...THE ECMWF AND GFS HAVE STARTED TO FOCUS TOWARDS LOW
PRESSURE ON A SOUTHERLY TRACK ALONG OR JUST SOUTH OF THE 40/70
BENCHMARK FOR WINTER STORMS. AT THIS POINT...THIS SOLUTION BRINGS
HEAVY SNOW...LIKELY FOCUSED MORE ON THE SOUTHERN AREAS OF THE CWA
MAINLY ON TUESDAY NIGHT INTO WEDNESDAY. THERE ARE STILL OTHER
SOLUTIONS...THE NAM HAS HIGH PRESSURE OVER THE REGION TUESDAY.
HOWEVER...AT THIS POINT...THE ECMWF/GFS SOLUTION APPEARS THE MOST
LIKELY. WILL TREND TOWARD THIS SOLUTION...BUT CONFIDENCE IS STILL
LOW.
THURSDAY AND FRIDAY...DESPITE ALL THE DISCREPANCIES/UNCERTAINTY FOR
EARLIER IN THE PERIOD...THESE TWO PERIODS HAVE FAIRLY GOOD AGREEMENT
AMONGST THE MODELS. NORTHWESTERLY FLOW WITH THE COOLEST TEMPS OF
THE SEASON THUS FAR MOVING IN ON STRONG COLD AIR ADVECTION. LOOKS
LIKE A COLD AND BRISK END TO THE WEEK.
&&
.AVIATION /21Z SATURDAY THROUGH THURSDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT
MODERATE...30 PERCENT TO 60 PERCENT
HIGH...GREATER THAN 60 PERCENT
OVERVIEW...MODERATE TO HIGH CONFIDENCE.
VFR CONDITIONS THROUGH SUNDAY NIGHT. SCATTERED LIGHT SNOW SHOWERS
SHOULD BE CONFINED TO BERKSHIRES THIS EVENING ALTHOUGH A FLAKE OR
TWO CANNOT BE RULED OUT AS FAR EAST AS THE CONNECTICUT RIVER
BEFORE 04Z. W-NW WINDS GUSTING TO 20-30 KTS MOST AREAS. WINDS MAY
DIMINISH TO 15 KTS IN THE INTERIOR OVERNIGHT. WINDS DIMINISHING
AGAIN IN THE LATE AFTERNOON SUNDAY EXCEPT ALONG THE COAST.
KBOS TAF...MODERATE TO HIGH CONFIDENCE.
VFR THROUGH SUNDAY NIGHT. W-NW WINDS WITH GUSTS TO 20-30 KT
TONIGHT AND SUNDAY.
KBDL TAF...HIGH CONFIDENCE. VFR THROUGH SUNDAY NIGHT. SLIGHT
CHANCE OF A FLURRY THIS EVENING. W-NW WINDS WITH GUSTS 20-30 KT
THIS EVENING AND AGAIN SUNDAY MID MORNING THROUGH MID AFTERNOON.
OUTLOOK...MONDAY THROUGH THURSDAY...
MONDAY...HIGH CONFIDENCE. VFR.
TUESDAY THROUGH WEDNESDAY MORNING...LOW CONFIDENCE. MVFR/IFR
CONDITIONS POSSIBLE IN POTENTIAL RA/SN/FZRA/SNPL.
WEDNESDAY AFTERNOON THROUGH THURSDAY...MODERATE TO HIGH CONFIDENCE.
VFR.
&&
.MARINE...
MODERATE CONFIDENCE INTO SUNDAY NIGHT...
GALE WARNINGS CONTINUE FOR THE COASTAL WATERS INCLUDING NANTUCKET
SOUND...EXCEPT FOR THE INNER HARBORS AND BAYS WHERE SMALL CRAFT
ADVISORIES ARE POSTED. AS AN UPPER LEVEL SHORT WAVE TROUGH SWINGS
THROUGH NORTHERN NEW ENGLAND OVERNIGHT...W TO NW WINDS WILL
CONTINUE TO INCREASE OVER THE COASTAL WATERS...REACHING 35 KTS
OVER THE GALE WARNING AREA AND CONTINUING INTO MUCH OF SUNDAY.
THERE IS A CHANCE THAT A FEW GUSTS TO GALE FORCE COULD OCCUR
CLOSER TO THE COAST IN THE SMALL CRAFT ADVISORY AREA...BUT
FREQUENT GUSTS ARE NOT EXPECTED. ONE CONCERN IS A GUST TO 44 KTS
AT WORCESTER AIRPORT RIGHT AT 4 PM... BUT WE ARE THINKING THAT
THIS IS ELEVATIONAL AND STILL RELATED TO THE MAXIMUM MIXING OF THE
AFTERNOON. WE WILL NEED TO WATCH THIS CLOSELY IN CASE GALES ARE
NEEDED EVERYWHERE ALONG THE COAST OVERNIGHT.
SEAS ARE FORECAST TO CONTINUE TO BUILD TO 8 TO 11 FEET ACROSS THE
OUTER WATERS TONIGHT.
WINDS SHOULD BEGIN TO DIMINISH TO BELOW GALE FORCE IN THE
AFTERNOON BUT SMALL CRAFT ADVISORY LEVEL WIND GUSTS TO 25 KTS MAY
CONTINUE OVER THE OUTER WATERS THROUGH SUNDAY NIGHT. SLOWLY
SUBSIDING SEAS SUNDAY NIGHT.
OUTLOOK...MONDAY THROUGH THURSDAY...
MODERATE CONFIDENCE THROUGH THE PERIOD.
SEAS WILL FALL BELOW 5 FEET LATE MONDAY AND REMAIN BELOW THROUGH
LATE TUESDAY. THEN SEAS WILL BUILD AGAIN AS LOW PRESSURE APPROACHES
THE WATERS LATE TUESDAY INTO WEDNESDAY AND REMAIN ABOVE 5 FEET
THROUGH THE PERIOD. WINDS WILL REMAIN BELOW 25 KTS THROUGH TUESDAY.
WINDS INCREASE TO 25 TO 30 KTS WEDNESDAY AND THURSDAY AS LOW
PRESSURE MOVES ACROSS THE WATERS. LOW PROBABILITY OF GALES LATE
WEDNESDAY INTO THURSDAY.
&&
.FIRE WEATHER...
NO HEADLINES ARE ANTICIPATED BUT FELT IT WAS WORTH MENTIONING THAT
THE MINIMUM RELATIVE HUMIDITIES WILL BE DOWN AROUND 30 PERCENT
SUNDAY AFTERNOON. WINDS WILL BE GUSTING TO 20 TO 30 MPH BUT WILL
BE DIMINISHING IN THE MID TO LATE AFTERNOON AT THE TIME OF THE
MINIMUM HUMIDITIES.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...GALE WARNING UNTIL 10 AM EST SUNDAY FOR ANZ232>235-237-256.
SMALL CRAFT ADVISORY UNTIL 7 PM EST SUNDAY FOR ANZ230-231-236-
251.
GALE WARNING UNTIL 1 PM EST SUNDAY FOR ANZ250-254-255.
&&
$$
SYNOPSIS...RLG/GAF
NEAR TERM...GAF
SHORT TERM...GAF
LONG TERM...RLG
AVIATION...RLG/GAF
MARINE...RLG/GAF
FIRE WEATHER...GAF
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
407 PM CST SAT NOV 24 2012
.DISCUSSION...
234 PM CST
THE FORECAST CHALLENGES FOR TODAY ARE MAINLY TEMPERATURES AS
READINGS LOOK TO WARM LATER THIS EVENING THROUGH THE DAY SUNDAY
THEN A COOL DOWN INTO MONDAY...FOLLOWED BY A WARM-UP WITH WHAT
LOOKS TO POTENTIALLY BE 50S TO END NOVEMBER AND START
METEOROLOGICAL WINTER.
THE STUBBORN CYCLONIC FLOW AND ITS PESKY STRATUS IS ON THE WAY OUT
WITH A SURFACE RIDGE AXIS MOVING QUICKLY OVER THE AREA THIS EVE.
MID-LEVEL WARM AIR ADVECTION CLOUDS ARE ALREADY SPREADING OVER THIS
RIDGE ACROSS WESTERN IL AND SHOULD QUICKLY EXPAND EAST THROUGH THE
EVE. BEFORE THE ARRIVAL OF THESE CLOUDS IN THE HOURS AFTER
SUNSET...EASTERN AREAS SHOULD SEE TEMPERATURE DROPS THROUGH THE
20S GIVEN LIGHT WINDS. A GRADUAL CLIMB IN TEMPERATURES IS THEN
EXPECTED AREA WIDE AS PRESSURE FALLS AND RETURN FLOW SPREAD IN.
TEMPERATURES ARE LIKELY TO CLIMB BACK TO THE UPPER 20S TO MID 30S
BY DAYBREAK ON SUNDAY.
THE WARM AIR ADVECTION CLOUDS TONIGHT ARE ASSOCIATED WITH A STRONG
UPPER LEVEL LOW MOVING EAST ACROSS NORTHERN SASKATCHEWAN AND
MANITOBA...AND MORE SO WITH A RELATED PV ANOMALY AND SHORT WAVE
EXTENDING SOUTHWARD. THIS WILL TRANSLATE INTO WI BY OVERNIGHT AND
ALREADY TO THE EASTERN GREAT LAKES BY SUNDAY MORNING. SUPPORT FOR
UPWARD MOTION DOES SPREAD THIS FAR SOUTH AS REFLECTED IN RAP AND
NAM Q-VECTOR CONVERGENCE FIELDS. HOWEVER...SATURATION AND MID-
LEVEL MOISTURE CONVERGENCE IS BETTER SITUATED TO THE NORTH. THIS
DISJOINT WILL LIKELY KEEP PRECIPITATION TO THE NORTH...THOUGH
FLURRIES COULD GET CLOSE TO THE WI/IL STATE LINE LATER THIS EVE.
THE WARM SECTOR OF THIS CLIPPER-LIKE SYSTEM WILL CONTINUE OVER THE
AREA INTO SUNDAY. THIS HAS OFFERED 40S TO THE WEST OF THE REGION
IN NEBRASKA TODAY...AND ENVISION LOWER TO MID 40S DURING THE DAY
SUNDAY HERE. AS THE COLD FRONT MOVES THROUGH...WINDS WILL TURN
MORE NORTHWEST BY NIGHT AND TEMPERATURES WILL FALL BACK INTO THE
20S FOR LOWS.
TRENDS CONTINUE TO SUPPORT THIS LOW-LEVEL COOL AIR AND RIDGING
PUSH FROM THE NORTH TO EVOLVE THE PRIMARY BAROCLINIC ZONE TO THE
SOUTH OF THE AREA ON MON NIGHT AND TUE...AND THUS KEEP THE
PRIMARY FORCING FOR PRECIPITATION THERE AS WELL. AS THIS UNFOLDS
THOUGH...THERE STILL IS A WINDOW FOR SMALL CHANCES OF LIGHT SNOW
ACROSS THE SOUTHERN FORECAST AREA...MAINLY LATER MONDAY AFTERNOON
AND NIGHT. THE SPREAD IN THE SREF AND GEFS MEMBERS IS NOW LOW OVER
THE AREA...SO CONFIDENCE ON THIS IS FAIRLY HIGH.
BEYOND THIS...TEMPERATURES WILL SLOWLY MODERATE THROUGH MID WEEK
AS UPPER LEVEL RIDGING ACROSS THE WESTERN STATES EASES EAST.
WITH A LARGE CLOSED LOW OFF THE WEST COAST FORECAST CONSISTENTLY
BY GUIDANCE...THERE WILL BE LITTLE PROGRESSION OF MAJOR WEATHER
SYSTEMS. A QUICK MOVING UPPER LEVEL JET MAX AND ASSOCIATED SHORT
WAVE IS SEEN ON THU NIGHT/FRIDAY WITHIN THE SUITE OF LONG RANGE
GUIDANCE. AGAIN THERE CONTINUES TO BE DECENT BUT SHORT-LIVED
DYNAMICS FORECAST WITH THIS. HAVE INCREASED POPS SOME FROM A
PROVIDED GUIDANCE BLEND. TEMPERATURE SPREAD BY DAYS 6 AND 7 IN THE
FORECAST REALLY INCREASES IN GUIDANCE...SO CONFIDENCE
DROPS...HOWEVER GUIDANCE IS FAVORING TEMPERATURES TO BE ABOVE
NORMAL. ONE OF THE REASONS FOR SUCH SPREAD LOOKS TO BE CLOUD
COVER...AS THE DETERMINISTIC GFS DRAGS UP QUITE A BIT OF LOW-LEVEL
JUICE WITH THE THU NIGHT/FRI WAVE THAT MAY BE TOUGH TO SCOUR THIS
TIME OF YEAR.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 22Z...
* NONE.
BMD
//DISCUSSION...UPDATED 18Z...
HIGH PRESSURE IS BUILDING INTO NORTHERN ILLINOIS AND NORTHWEST
INDIANA AT MIDDAY. THIS IS FINALLY ERODING THE CLOUD DECK THAT
HAS PERSISTED THROUGH THE MORNING. HOWEVER THE CLEARING WILL BE
SHORT LIVED AS MIDDLE AND HIGH LEVEL CLOUDS AHEAD OF AN
APPROACHING UPPER LEVEL TROUGH ARE ALREADY INTO EASTERN IA AND
MOVING TO THE EAST. THESE VFR-LEVEL CEILINGS WILL MOVE INTO ALL THE
TERMINALS LATE THIS AFTERNOON INTO THE EVENING HOURS. THE TROUGH
HAS LIMITED MOISTURE TO WORK WITH...SO NOT EXPECTING ANY
PRECIPITATION WITH IT. THE BIGGEST IMPACT WILL BE TO SHIFT THE
WINDS TO THE NORTHWEST AND SCATTER OUT THE CEILINGS AS IT MOVES
ACROSS THE AREA ON SUNDAY.
PAW
//ORD AND MDW CONFIDENCE...UPDATED 22Z...
* HIGH CONFIDENCE IN ALL FORECAST ELEMENTS.
BMD
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT...VFR.
MONDAY...VFR. CHC OF LGT SN AND MVFR IN THE EVENING.
TUESDAY...CHC OF MVFR EARLY...TRENDING VFR LATE.
WEDNESDAY THROUGH THURSDAY...VFR.
FRIDAY...VFR. SLIGHT CHC LGT RA/SN AND PATCHY MVFR.
BEACHLER
&&
.MARINE...
217 PM...A RIDGE OF HIGH PRESSURE WILL PASS ACROSS LAKE MICHIGAN
EARLY THIS EVENING AS LOW PRESSURE OVER SOUTHERN MANITOBA MOVES
EAST ACROSS THE NORTHERN LAKES SUNDAY AND WEAKENS SUNDAY NIGHT.
THE GRADIENT WILL TIGHTEN TONIGHT BETWEEN THE APPROACHING LOW AND
THE WEAKENING RIDGE. WEST WINDS WILL SHIFT SOUTHWESTERLY THIS
EVENING AND STEADILY INCREASE TO 15-25KTS BY LATE EVENING AND
OVERNIGHT. SOME GUSTS TO 30 KTS ARE POSSIBLE ESPECIALLY OVER THE
SOUTHERN PART OF THE LAKE WHERE THE GRADIENT WILL BE TIGHTEST. A
TRAILING COLD FRONT FROM THIS LOW WILL MOVE ACROSS THE LAKE SUNDAY
AFTERNOON SHIFTING WINDS WESTERLY. AS ANOTHER AREA OF HIGH
PRESSURE MOVES SOUTHEAST FROM THE NORTHERN PLAINS SUNDAY NIGHT TO
THE SOUTHERN LAKES AND OHIO VALLEY MONDAY...THE GRADIENT WILL ONCE
AGAIN TIGHTEN WITH NORTHWEST WINDS 20-25KTS EXPECTED. GRADIENT
COULD BE STRONG ENOUGH FOR GUSTS TO 30KTS OVER NORTHERN LAKE
MICHIGAN. AS THIS HIGH SETTLES SOUTH OF THE LAKE ON TUESDAY...
WINDS WILL TURN SOUTHWESTERLY AND SHOULD RAPIDLY STRENGTHEN
TUESDAY AFTERNOON AS ANOTHER LOW MOVES ACROSS ONTARIO AND THE
NORTHERN LAKES WITH 30KTS AGAIN POSSIBLE OVER THE NORTHERN HALF OF
THE LAKE. ANOTHER AREA OF HIGH PRESSURE WILL MOVE ACROSS THE
MIDWEST AND LAKES REGION MID WEEK. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
234 PM CST SAT NOV 24 2012
.DISCUSSION...
234 PM CST
THE FORECAST CHALLENGES FOR TODAY ARE MAINLY TEMPERATURES AS
READINGS LOOK TO WARM LATER THIS EVENING THROUGH THE DAY SUNDAY
THEN A COOL DOWN INTO MONDAY...FOLLOWED BY A WARM-UP WITH WHAT
LOOKS TO POTENTIALLY BE 50S TO END NOVEMBER AND START
METEOROLOGICAL WINTER.
THE STUBBORN CYCLONIC FLOW AND ITS PESKY STRATUS IS ON THE WAY OUT
WITH A SURFACE RIDGE AXIS MOVING QUICKLY OVER THE AREA THIS EVE.
MID-LEVEL WARM AIR ADVECTION CLOUDS ARE ALREADY SPREADING OVER THIS
RIDGE ACROSS WESTERN IL AND SHOULD QUICKLY EXPAND EAST THROUGH THE
EVE. BEFORE THE ARRIVAL OF THESE CLOUDS IN THE HOURS AFTER
SUNSET...EASTERN AREAS SHOULD SEE TEMPERATURE DROPS THROUGH THE
20S GIVEN LIGHT WINDS. A GRADUAL CLIMB IN TEMPERATURES IS THEN
EXPECTED AREA WIDE AS PRESSURE FALLS AND RETURN FLOW SPREAD IN.
TEMPERATURES ARE LIKELY TO CLIMB BACK TO THE UPPER 20S TO MID 30S
BY DAYBREAK ON SUNDAY.
THE WARM AIR ADVECTION CLOUDS TONIGHT ARE ASSOCIATED WITH A STRONG
UPPER LEVEL LOW MOVING EAST ACROSS NORTHERN SASKATCHEWAN AND
MANITOBA...AND MORE SO WITH A RELATED PV ANOMALY AND SHORT WAVE
EXTENDING SOUTHWARD. THIS WILL TRANSLATE INTO WI BY OVERNIGHT AND
ALREADY TO THE EASTERN GREAT LAKES BY SUNDAY MORNING. SUPPORT FOR
UPWARD MOTION DOES SPREAD THIS FAR SOUTH AS REFLECTED IN RAP AND
NAM Q-VECTOR CONVERGENCE FIELDS. HOWEVER...SATURATION AND MID-
LEVEL MOISTURE CONVERGENCE IS BETTER SITUATED TO THE NORTH. THIS
DISJOINT WILL LIKELY KEEP PRECIPITATION TO THE NORTH...THOUGH
FLURRIES COULD GET CLOSE TO THE WI/IL STATE LINE LATER THIS EVE.
THE WARM SECTOR OF THIS CLIPPER-LIKE SYSTEM WILL CONTINUE OVER THE
AREA INTO SUNDAY. THIS HAS OFFERED 40S TO THE WEST OF THE REGION
IN NEBRASKA TODAY...AND ENVISION LOWER TO MID 40S DURING THE DAY
SUNDAY HERE. AS THE COLD FRONT MOVES THROUGH...WINDS WILL TURN
MORE NORTHWEST BY NIGHT AND TEMPERATURES WILL FALL BACK INTO THE
20S FOR LOWS.
TRENDS CONTINUE TO SUPPORT THIS LOW-LEVEL COOL AIR AND RIDGING
PUSH FROM THE NORTH TO EVOLVE THE PRIMARY BAROCLINIC ZONE TO THE
SOUTH OF THE AREA ON MON NIGHT AND TUE...AND THUS KEEP THE
PRIMARY FORCING FOR PRECIPITATION THERE AS WELL. AS THIS UNFOLDS
THOUGH...THERE STILL IS A WINDOW FOR SMALL CHANCES OF LIGHT SNOW
ACROSS THE SOUTHERN FORECAST AREA...MAINLY LATER MONDAY AFTERNOON
AND NIGHT. THE SPREAD IN THE SREF AND GEFS MEMBERS IS NOW LOW OVER
THE AREA...SO CONFIDENCE ON THIS IS FAIRLY HIGH.
BEYOND THIS...TEMPERATURES WILL SLOWLY MODERATE THROUGH MID WEEK
AS UPPER LEVEL RIDGING ACROSS THE WESTERN STATES EASES EAST.
WITH A LARGE CLOSED LOW OFF THE WEST COAST FORECAST CONSISTENTLY
BY GUIDANCE...THERE WILL BE LITTLE PROGRESSION OF MAJOR WEATHER
SYSTEMS. A QUICK MOVING UPPER LEVEL JET MAX AND ASSOCIATED SHORT
WAVE IS SEEN ON THU NIGHT/FRIDAY WITHIN THE SUITE OF LONG RANGE
GUIDANCE. AGAIN THERE CONTINUES TO BE DECENT BUT SHORT-LIVED
DYNAMICS FORECAST WITH THIS. HAVE INCREASED POPS SOME FROM A
PROVIDED GUIDANCE BLEND. TEMPERATURE SPREAD BY DAYS 6 AND 7 IN THE
FORECAST REALLY INCREASES IN GUIDANCE...SO CONFIDENCE
DROPS...HOWEVER GUIDANCE IS FAVORING TEMPERATURES TO BE ABOVE
NORMAL. ONE OF THE REASONS FOR SUCH SPREAD LOOKS TO BE CLOUD
COVER...AS THE DETERMINISTIC GFS DRAGS UP QUITE A BIT OF LOW-LEVEL
JUICE WITH THE THU NIGHT/FRI WAVE THAT MAY BE TOUGH TO SCOUR THIS
TIME OF YEAR.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* LIGHT SOUTHWEST TO WEST WIND.
PAW
//DISCUSSION...UPDATED 18Z...
HIGH PRESSURE IS BUILDING INTO NORTHERN ILLINOIS AND NORTHWEST
INDIANA AT MIDDAY. THIS IS FINALLY ERODING THE CLOUD DECK THAT
HAS PERSISTED THROUGH THE MORNING. HOWEVER THE CLEARING WILL BE
SHORT LIVED AS MIDDLE AND HIGH LEVEL CLOUDS AHEAD OF AN
APPROACHING UPPER LEVEL TROUGH ARE ALREADY INTO EASTERN IA AND
MOVING TO THE EAST. THESE VFR-LEVEL WILL CEILINGS TO MOVE INTO
ALL THE TERMINALS LATE THIS AFTERNOON INTO THE EVENING HOURS. THE
TROUGH HAS LIMITED MOISTURE TO WORK WITH...SO NOT EXPECTING ANY
PRECIPITATION WITH IT. THE BIGGEST IMPACT WILL BE TO SHIFT THE
WINDS TO THE NORTHWEST AND SCATTER OUT THE CEILINGS AS IT MOVES
ACROSS THE AREA ON SUNDAY.
PAW
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE IN WIND TREND.
PAW
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT...VFR.
MONDAY...VFR. CHC OF LGT SN AND MVFR IN THE EVENING.
TUESDAY...CHC OF MVFR EARLY...TRENDING VFR LATE.
WEDNESDAY THROUGH THURSDAY...VFR.
FRIDAY...VFR. SLIGHT CHC LGT RA/SN AND PATCHY MVFR.
BEACHLER
&&
.MARINE...
217 PM...A RIDGE OF HIGH PRESSURE WILL PASS ACROSS LAKE MICHIGAN
EARLY THIS EVENING AS LOW PRESSURE OVER SOUTHERN MANITOBA MOVES
EAST ACROSS THE NORTHERN LAKES SUNDAY AND WEAKENS SUNDAY NIGHT.
THE GRADIENT WILL TIGHTEN TONIGHT BETWEEN THE APPROACHING LOW AND
THE WEAKENING RIDGE. WEST WINDS WILL SHIFT SOUTHWESTERLY THIS
EVENING AND STEADILY INCREASE TO 15-25KTS BY LATE EVENING AND
OVERNIGHT. SOME GUSTS TO 30 KTS ARE POSSIBLE ESPECIALLY OVER THE
SOUTHERN PART OF THE LAKE WHERE THE GRADIENT WILL BE TIGHTEST. A
TRAILING COLD FRONT FROM THIS LOW WILL MOVE ACROSS THE LAKE SUNDAY
AFTERNOON SHIFTING WINDS WESTERLY. AS ANOTHER AREA OF HIGH
PRESSURE MOVES SOUTHEAST FROM THE NORTHERN PLAINS SUNDAY NIGHT TO
THE SOUTHERN LAKES AND OHIO VALLEY MONDAY...THE GRADIENT WILL ONCE
AGAIN TIGHTEN WITH NORTHWEST WINDS 20-25KTS EXPECTED. GRADIENT
COULD BE STRONG ENOUGH FOR GUSTS TO 30KTS OVER NORTHERN LAKE
MICHIGAN. AS THIS HIGH SETTLES SOUTH OF THE LAKE ON TUESDAY...
WINDS WILL TURN SOUTHWESTERLY AND SHOULD RAPIDLY STRENGTHEN
TUESDAY AFTERNOON AS ANOTHER LOW MOVES ACROSS ONTARIO AND THE
NORTHERN LAKES WITH 30KTS AGAIN POSSIBLE OVER THE NORTHERN HALF OF
THE LAKE. ANOTHER AREA OF HIGH PRESSURE WILL MOVE ACROSS THE
MIDWEST AND LAKES REGION MID WEEK. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 4 PM SATURDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
217 PM CST SAT NOV 24 2012
.DISCUSSION...
930 AM CST
HAVE MADE SOME ADJUSTMENTS TO THE FORECAST TO HOLD ONTO CLOUDS
LONGER...PARTICULARLY ACROSS NORTHEAST IL AND NORTHWEST IN...AND
ACCORDINGLY HAVE LOWERED FORECAST HIGH TEMPS BY A COUPLE DEGREES
IN PLACES.
THE GOES WATER VAPOR LOOP THIS MORNING IS REFLECTING DRYING MOVING
EASTWARD OVER THE AREA...AND REGIONAL SOUNDINGS REFLECTED THAT IN
THE MID-LEVELS. HOWEVER...HEIGHT RISES AT 700 MB WERE NEUTRAL THIS
MORNING INDICATING LIMITED OVERALL SUPPRESSION...AS WAS 700 TO
850 MB TEMPERATURE ADVECTION /DVN AND GRB EVEN COOLED AT 700 MB/.
WITH PROFILERS ALSO INDICATING MORE OF A NORTHERLY FLOW IN THE
LOW-LEVELS...GENERAL CYCLONIC FLOW APPEARS TO BE HANGING ON
LONGER THAN INITIAL THOUGHT...ESPECIALLY ACROSS EASTERN AREAS.
THIS REGIME WILL NOT AID THE CLOUDS IN CLEARING THROUGH EARLY
AFTERNOON...EVEN WITH THE MOIST LAYER AT THE CLOUD HEIGHT
REMAINING SHALLOW /1000 FT OR LESS/ ON AMDAR SOUNDINGS AND THE GRB
RAOB THIS MORNING. ADAPTING AN AREA AMDAR SOUNDING IT WOULD SEEM
THAT SURFACE TEMPS IN THE MID 30S WOULD BE NEEDED TO MIX OUT SOME
OF THE CLOUD COVER...AND WITH NO WARMING HAPPENING UNDER THE HEART
OF THE CLOUDS AND MUCH LOWER STARTING TEMPERATURES THIS MORNING AT
THE PERIPHERY OF THE CLOUD SHIELD...DO NOT SEE THIS HAPPENING
ANYTIME SOON. SO OUTSIDE OF A COUPLE HOLES FROM THE WEAK TO
SUPPRESSION ALOFT...THE CLOUD SHIELD SHOULD ONLY OOZE ITS WAY
EAST THROUGH EARLY AFTERNOON THEN INCREASE IN SPEED WITH THE WARM
AIR ADVECTION PATTERN. EVEN AT 3 PM THOUGH...PARCEL TRAJECTORIES
OVER EASTERN AREAS ARE FROM CLOUD COVERED SOUTH CENTRAL WI AT
PRESENT. THE RAP 900 MB RH FORECAST SEEMS TO CAPTURE THE EVOLUTION
WELL...AND IS IN GOOD AGREEMENT WITH THE NARRE-TL CLOUD FORECAST.
SO HAVE COLLABORATED THESE IDEAS INTO THE CLOUD COVER FORECAST
AND KEPT TEMPERATURES CLIMBING AT ABOUT 1 DEGREE PER TWO HOURS
ACROSS THE EAST THROUGH EARLY AFTERNOON. OVERALL THIS TOOK HIGHS
DOWN 1 TO 3 DEGREES IN PLACES.
MTF
//PREV DISCUSSION...
352 AM CST
FOLLOWING AN ACTIVE HOLIDAY WEEK WITH DENSE FOG THANKSGIVING EVE
MORNING FOLLOWED BY NEAR RECORD WARMTH ON THANKSGIVING DAY... AND
THEN A JOLT BACK TO REALITY COURTESY OF A STRONG COLD FRONT ON
BLACK FRIDAY... THE COMING WEEKEND WILL BE RELATIVELY QUIET WITH
CHILLY DAYTIME HIGHS SATURDAY ONLY IN THE 30S... WITH MAX TEMPS
SUNDAY RETURNING TO AROUND SEASONAL NORMS.
AS DEEP SURFACE LOW PRESSURE OVER QUEBEC CONTINUES TO PUSH NE AWAY
FROM THE GREAT LAKES... RIDGING WILL BUILD QUICKLY INTO NRN IL/NW IN
THIS MORNING. THE STRENGTHENING ANTI-CYCLONIC FLOW COMBINED WITH
INCREASED SUBSIDENCE THROUGH THE MID LEVELS SHOULD DRY OUT STUBBORN
LINGERING SC FAIRLY QUICKLY FROM WEST TO EAST THROUGH THE MID
MORNING HOURS. DESPITE SUNSHINE THROUGH THE REMAINDER OF THE DAY...
TEMPS WILL ONLY RISE INTO THE MID 30S WITH COLD AIR AT 850 MB
HANGING AROUND UNTIL THE BETTER WARM AID ADVECTION (WAA) PATTERN
SETS UP ACROSS THE AREA THIS EVENING.
WITH LOW LEVEL WAA COMBINED WITH RISING HEIGHTS ALOFT EXPECT MIN
TEMPS TONIGHT TO BE REALIZED THIS EVENING WITH TEMPS THEN STEADYING
OUT BY LATE EVENING AND PROBABLY EVEN RISING A FEW DEGREES DURING
THE OVERNIGHT. EXPECT CLOUDS TO INCREASE AHEAD OF A FAIRLY POTENT
SECONDARY SHORTWAVE TROUGH DROPPING INTO THE UPPER GREAT LAKES
TONIGHT INTO EARLY SUNDAY. ANY FORCING OF CONSEQUENCE REMAINS NORTH
OF THE LOCAL AREA HOWEVER AND HENCE EXPECT PRECIP TO DO LIKEWISE.
SUNDAY SHAPING UP TO BE A FAIRLY TYPICAL LATE NOVEMBER DAY WITH
CLOUDS GIVING WAY TO SOME SUN AND TEMPS TOPPING OUT IN THE MID 40S.
A WEAK COLD FRONT ASSOCIATED WITH AFOREMENTIONED UPPER SHORTWAVE
TROUGH WILL SWEEP ACROSS THE REGION DURING THE AFTERNOON BUT SHOULD
RESULT IN LITTLE MORE THAN A WIND SHIFT AS COLDEST CORE OF AIR
BEHIND IT WILL REMAIN TO OUR NORTH.
MODELS CONTINUE TO TREND FARTHER SOUTH WITH LOW PRESSURE DEVELOPING
OVER THE SOUTHERN PLANS ON MONDAY AND THEN TRACKING ACROSS THE LOWER
MISSISSIPPI VALLEY MONDAY NIGHT AND ACROSS THE SOUTH ON TUES. WITH
THIS TREND BECOMING MORE PRONOUNCED... WILL CONTINUE PREVIOUS
FORECAST TREND OF LOWERING POPS ACROSS THE CWFA ANOTHER NOTCH FOR
THE MON NIGHT-TUES TIME PERIOD. SHOULD THIS MORE SOUTHERN TRACK
VERIFY... AT LEAST THE NORTHERN 2/3 OF THE CWFA IF NOT THE ENTIRE
AREA WILL PROBABLY SEE NO PRECIP AT ALL... HOWEVER GIVEN SOME
UNCERTAINTY REMAINING IN THE ENSEMBLE SPREAD... WOULD LIKE TO SEE
ANOTHER MODEL RUN BEFORE PULLING COMPLETELY.
A DRY NORTHWESTERLY FLOW ALOFT SETS UP FOR WED AND THURS WITH
BROAD HIGH PRESSURE DOMINATING AT THE SURFACE AND SEASONAL TEMPS.
THEN LEE SIDE CYCLOGENEIS DEVELOPS IN RESPONSE TO AN UPPER LEVEL
TROUGH MOVING INTO THE CENTRAL PLAINS LATER ON THURSDAY AND MOVES
INTO THE LOCAL AREA LATE THURSDAY NIGHT INTO FRIDAY. HAVE
INTRODUCED LOW POPS WITH THIS FEATURE AS DYNAMICS INITIALLY
APPEAR REASONABLY IMPRESSIVE HOWEVER AT DAYS 6-7 WOULD LIKE TO
SEE GREATER MODEL CONSISTENCY BEFORE INTRODUCING MENTION OF
ANYTHING MORE THAN A SLIGHT CHANCE OF PRECIP. THE AIR MASS IN
PLACE AT THE TIME WILL BE SUFFICIENTLY COLD ENOUGH TO SUPPORT A
MIX OF RAIN AND SNOW INITIALLY EARLY FRIDAY BEFORE INCREASING WAA
WARMS THE COLUMN TO AT OR ABOVE THE FREEZING MARK.
ED F
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* LIGHT SOUTHWEST TO WEST WIND.
PAW
//DISCUSSION...UPDATED 18Z...
HIGH PRESSURE IS BUILDING INTO NORTHERN ILLINOIS AND NORTHWEST
INDIANA AT MIDDAY. THIS IS FINALLY ERODING THE CLOUD DECK THAT
HAS PERSISTED THROUGH THE MORNING. HOWEVER THE CLEARING WILL BE
SHORT LIVED AS MIDDLE AND HIGH LEVEL CLOUDS AHEAD OF AN
APPROACHING UPPER LEVEL TROUGH ARE ALREADY INTO EASTERN IA AND
MOVING TO THE EAST. THESE VFR-LEVEL WILL CEILINGS TO MOVE INTO
ALL THE TERMINALS LATE THIS AFTERNOON INTO THE EVENING HOURS. THE
TROUGH HAS LIMITED MOISTURE TO WORK WITH...SO NOT EXPECTING ANY
PRECIPITATION WITH IT. THE BIGGEST IMPACT WILL BE TO SHIFT THE
WINDS TO THE NORTHWEST AND SCATTER OUT THE CEILINGS AS IT MOVES
ACROSS THE AREA ON SUNDAY.
PAW
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE IN WIND TREND.
PAW
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT...VFR.
MONDAY...VFR. CHC OF LGT SN AND MVFR IN THE EVENING.
TUESDAY...CHC OF MVFR EARLY...TRENDING VFR LATE.
WEDNESDAY THROUGH THURSDAY...VFR.
FRIDAY...VFR. SLIGHT CHC LGT RA/SN AND PATCHY MVFR.
BEACHLER
&&
.MARINE...
217 PM...A RIDGE OF HIGH PRESSURE WILL PASS ACROSS LAKE MICHIGAN
EARLY THIS EVENING AS LOW PRESSURE OVER SOUTHERN MANITOBA MOVES
EAST ACROSS THE NORTHERN LAKES SUNDAY AND WEAKENS SUNDAY NIGHT.
THE GRADIENT WILL TIGHTEN TONIGHT BETWEEN THE APPROACHING LOW AND
THE WEAKENING RIDGE. WEST WINDS WILL SHIFT SOUTHWESTERLY THIS
EVENING AND STEADILY INCREASE TO 15-25KTS BY LATE EVENING AND
OVERNIGHT. SOME GUSTS TO 30 KTS ARE POSSIBLE ESPECIALLY OVER THE
SOUTHERN PART OF THE LAKE WHERE THE GRADIENT WILL BE TIGHTEST. A
TRAILING COLD FRONT FROM THIS LOW WILL MOVE ACROSS THE LAKE SUNDAY
AFTERNOON SHIFTING WINDS WESTERLY. AS ANOTHER AREA OF HIGH
PRESSURE MOVES SOUTHEAST FROM THE NORTHERN PLAINS SUNDAY NIGHT TO
THE SOUTHERN LAKES AND OHIO VALLEY MONDAY...THE GRADIENT WILL ONCE
AGAIN TIGHTEN WITH NORTHWEST WINDS 20-25KTS EXPECTED. GRADIENT
COULD BE STRONG ENOUGH FOR GUSTS TO 30KTS OVER NORTHERN LAKE
MICHIGAN. AS THIS HIGH SETTLES SOUTH OF THE LAKE ON TUESDAY...
WINDS WILL TURN SOUTHWESTERLY AND SHOULD RAPIDLY STRENGTHEN
TUESDAY AFTERNOON AS ANOTHER LOW MOVES ACROSS ONTARIO AND THE
NORTHERN LAKES WITH 30KTS AGAIN POSSIBLE OVER THE NORTHERN HALF OF
THE LAKE. ANOTHER AREA OF HIGH PRESSURE WILL MOVE ACROSS THE
MIDWEST AND LAKES REGION MID WEEK. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 4 PM SATURDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
148 PM CST SAT NOV 24 2012
.DISCUSSION...
930 AM CST
HAVE MADE SOME ADJUSTMENTS TO THE FORECAST TO HOLD ONTO CLOUDS
LONGER...PARTICULARLY ACROSS NORTHEAST IL AND NORTHWEST IN...AND
ACCORDINGLY HAVE LOWERED FORECAST HIGH TEMPS BY A COUPLE DEGREES
IN PLACES.
THE GOES WATER VAPOR LOOP THIS MORNING IS REFLECTING DRYING MOVING
EASTWARD OVER THE AREA...AND REGIONAL SOUNDINGS REFLECTED THAT IN
THE MID-LEVELS. HOWEVER...HEIGHT RISES AT 700 MB WERE NEUTRAL THIS
MORNING INDICATING LIMITED OVERALL SUPPRESSION...AS WAS 700 TO
850 MB TEMPERATURE ADVECTION /DVN AND GRB EVEN COOLED AT 700 MB/.
WITH PROFILERS ALSO INDICATING MORE OF A NORTHERLY FLOW IN THE
LOW-LEVELS...GENERAL CYCLONIC FLOW APPEARS TO BE HANGING ON
LONGER THAN INITIAL THOUGHT...ESPECIALLY ACROSS EASTERN AREAS.
THIS REGIME WILL NOT AID THE CLOUDS IN CLEARING THROUGH EARLY
AFTERNOON...EVEN WITH THE MOIST LAYER AT THE CLOUD HEIGHT
REMAINING SHALLOW /1000 FT OR LESS/ ON AMDAR SOUNDINGS AND THE GRB
RAOB THIS MORNING. ADAPTING AN AREA AMDAR SOUNDING IT WOULD SEEM
THAT SURFACE TEMPS IN THE MID 30S WOULD BE NEEDED TO MIX OUT SOME
OF THE CLOUD COVER...AND WITH NO WARMING HAPPENING UNDER THE HEART
OF THE CLOUDS AND MUCH LOWER STARTING TEMPERATURES THIS MORNING AT
THE PERIPHERY OF THE CLOUD SHIELD...DO NOT SEE THIS HAPPENING
ANYTIME SOON. SO OUTSIDE OF A COUPLE HOLES FROM THE WEAK TO
SUPPRESSION ALOFT...THE CLOUD SHIELD SHOULD ONLY OOZE ITS WAY
EAST THROUGH EARLY AFTERNOON THEN INCREASE IN SPEED WITH THE WARM
AIR ADVECTION PATTERN. EVEN AT 3 PM THOUGH...PARCEL TRAJECTORIES
OVER EASTERN AREAS ARE FROM CLOUD COVERED SOUTH CENTRAL WI AT
PRESENT. THE RAP 900 MB RH FORECAST SEEMS TO CAPTURE THE EVOLUTION
WELL...AND IS IN GOOD AGREEMENT WITH THE NARRE-TL CLOUD FORECAST.
SO HAVE COLLABORATED THESE IDEAS INTO THE CLOUD COVER FORECAST
AND KEPT TEMPERATURES CLIMBING AT ABOUT 1 DEGREE PER TWO HOURS
ACROSS THE EAST THROUGH EARLY AFTERNOON. OVERALL THIS TOOK HIGHS
DOWN 1 TO 3 DEGREES IN PLACES.
MTF
//PREV DISCUSSION...
352 AM CST
FOLLOWING AN ACTIVE HOLIDAY WEEK WITH DENSE FOG THANKSGIVING EVE
MORNING FOLLOWED BY NEAR RECORD WARMTH ON THANKSGIVING DAY... AND
THEN A JOLT BACK TO REALITY COURTESY OF A STRONG COLD FRONT ON
BLACK FRIDAY... THE COMING WEEKEND WILL BE RELATIVELY QUIET WITH
CHILLY DAYTIME HIGHS SATURDAY ONLY IN THE 30S... WITH MAX TEMPS
SUNDAY RETURNING TO AROUND SEASONAL NORMS.
AS DEEP SURFACE LOW PRESSURE OVER QUEBEC CONTINUES TO PUSH NE AWAY
FROM THE GREAT LAKES... RIDGING WILL BUILD QUICKLY INTO NRN IL/NW IN
THIS MORNING. THE STRENGTHENING ANTI-CYCLONIC FLOW COMBINED WITH
INCREASED SUBSIDENCE THROUGH THE MID LEVELS SHOULD DRY OUT STUBBORN
LINGERING SC FAIRLY QUICKLY FROM WEST TO EAST THROUGH THE MID
MORNING HOURS. DESPITE SUNSHINE THROUGH THE REMAINDER OF THE DAY...
TEMPS WILL ONLY RISE INTO THE MID 30S WITH COLD AIR AT 850 MB
HANGING AROUND UNTIL THE BETTER WARM AID ADVECTION (WAA) PATTERN
SETS UP ACROSS THE AREA THIS EVENING.
WITH LOW LEVEL WAA COMBINED WITH RISING HEIGHTS ALOFT EXPECT MIN
TEMPS TONIGHT TO BE REALIZED THIS EVENING WITH TEMPS THEN STEADYING
OUT BY LATE EVENING AND PROBABLY EVEN RISING A FEW DEGREES DURING
THE OVERNIGHT. EXPECT CLOUDS TO INCREASE AHEAD OF A FAIRLY POTENT
SECONDARY SHORTWAVE TROUGH DROPPING INTO THE UPPER GREAT LAKES
TONIGHT INTO EARLY SUNDAY. ANY FORCING OF CONSEQUENCE REMAINS NORTH
OF THE LOCAL AREA HOWEVER AND HENCE EXPECT PRECIP TO DO LIKEWISE.
SUNDAY SHAPING UP TO BE A FAIRLY TYPICAL LATE NOVEMBER DAY WITH
CLOUDS GIVING WAY TO SOME SUN AND TEMPS TOPPING OUT IN THE MID 40S.
A WEAK COLD FRONT ASSOCIATED WITH AFOREMENTIONED UPPER SHORTWAVE
TROUGH WILL SWEEP ACROSS THE REGION DURING THE AFTERNOON BUT SHOULD
RESULT IN LITTLE MORE THAN A WIND SHIFT AS COLDEST CORE OF AIR
BEHIND IT WILL REMAIN TO OUR NORTH.
MODELS CONTINUE TO TREND FARTHER SOUTH WITH LOW PRESSURE DEVELOPING
OVER THE SOUTHERN PLANS ON MONDAY AND THEN TRACKING ACROSS THE LOWER
MISSISSIPPI VALLEY MONDAY NIGHT AND ACROSS THE SOUTH ON TUES. WITH
THIS TREND BECOMING MORE PRONOUNCED... WILL CONTINUE PREVIOUS
FORECAST TREND OF LOWERING POPS ACROSS THE CWFA ANOTHER NOTCH FOR
THE MON NIGHT-TUES TIME PERIOD. SHOULD THIS MORE SOUTHERN TRACK
VERIFY... AT LEAST THE NORTHERN 2/3 OF THE CWFA IF NOT THE ENTIRE
AREA WILL PROBABLY SEE NO PRECIP AT ALL... HOWEVER GIVEN SOME
UNCERTAINTY REMAINING IN THE ENSEMBLE SPREAD... WOULD LIKE TO SEE
ANOTHER MODEL RUN BEFORE PULLING COMPLETELY.
A DRY NORTHWESTERLY FLOW ALOFT SETS UP FOR WED AND THURS WITH
BROAD HIGH PRESSURE DOMINATING AT THE SURFACE AND SEASONAL TEMPS.
THEN LEE SIDE CYCLOGENEIS DEVELOPS IN RESPONSE TO AN UPPER LEVEL
TROUGH MOVING INTO THE CENTRAL PLAINS LATER ON THURSDAY AND MOVES
INTO THE LOCAL AREA LATE THURSDAY NIGHT INTO FRIDAY. HAVE
INTRODUCED LOW POPS WITH THIS FEATURE AS DYNAMICS INITIALLY
APPEAR REASONABLY IMPRESSIVE HOWEVER AT DAYS 6-7 WOULD LIKE TO
SEE GREATER MODEL CONSISTENCY BEFORE INTRODUCING MENTION OF
ANYTHING MORE THAN A SLIGHT CHANCE OF PRECIP. THE AIR MASS IN
PLACE AT THE TIME WILL BE SUFFICIENTLY COLD ENOUGH TO SUPPORT A
MIX OF RAIN AND SNOW INITIALLY EARLY FRIDAY BEFORE INCREASING WAA
WARMS THE COLUMN TO AT OR ABOVE THE FREEZING MARK.
ED F
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* LIGHT SOUTHWEST TO WEST WIND.
PAW
//DISCUSSION...UPDATED 18Z...
HIGH PRESSURE IS BUILDING INTO NORTHERN ILLINOIS AND NORTHWEST
INDIANA AT MIDDAY. THIS IS FINALLY ERODING THE CLOUD DECK THAT
HAS PERSISTED THROUGH THE MORNING. HOWEVER THE CLEARING WILL BE
SHORT LIVED AS MIDDLE AND HIGH LEVEL CLOUDS AHEAD OF AN
APPROACHING UPPER LEVEL TROUGH ARE ALREADY INTO EASTERN IA AND
MOVING TO THE EAST. THESE VFR-LEVEL WILL CEILINGS TO MOVE INTO
ALL THE TERMINALS LATE THIS AFTERNOON INTO THE EVENING HOURS. THE
TROUGH HAS LIMITED MOISTURE TO WORK WITH...SO NOT EXPECTING ANY
PRECIPITATION WITH IT. THE BIGGEST IMPACT WILL BE TO SHIFT THE
WINDS TO THE NORTHWEST AND SCATTER OUT THE CEILINGS AS IT MOVES
ACROSS THE AREA ON SUNDAY.
PAW
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE IN WIND TREND.
PAW
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT...VFR.
MONDAY...VFR. CHC OF LGT SN AND MVFR IN THE EVENING.
TUESDAY...CHC OF MVFR EARLY...TRENDING VFR LATE.
WEDNESDAY THROUGH THURSDAY...VFR.
FRIDAY...VFR. SLIGHT CHC LGT RA/SN AND PATCHY MVFR.
BEACHLER
&&
.MARINE...
258 AM CST
OCCASIONAL GALES CONTINUE ACROSS THE NORTHERN HALF OF LAKE MICHIGAN
EARLY THIS MORNING...HOWEVER THE FREQUENCY CONTINUES TO DIMINISH.
THUS IT APPEARS THE GALE WARNING WILL BE ALLOWED TO EXPIRE AT
ISSUANCE OF THE NEW GLF. WILL MENTION AN OCCASIONAL GALE FORCE GUST
TO 35 KT THROUGH DAYBREAK. THEN EXPECT WINDS TO STEADILY DIMINISH.
HIGH PRESSURE WILL BEGIN TO BUILD IN FROM THE WEST...WHICH WILL
ALLOW WINDS TO FURTHER DIMINISH AND BECOME WESTERLY THIS
AFTERNOON. WILL CONTINUE TO FEATURE THE SMALL CRAFT ADVISORY
THROUGH EARLY THIS AFTERNOON...POSSIBLY ENDING EARLIER FOR THE
ILLINOIS NEARSHORE WATERS. WINDS WILL CONTINUE TO DIMINISH
THROUGHOUT THE AFTERNOON AND EARLY EVENING...HOWEVER THE HIGH
PRESSURE WILL QUICKLY DRIFT SOUTHEAST OF THE REGION. THIS WILL
ALLOW ANOTHER TIGHT GRADIENT TO RETURN LATE TONIGHT WITH WINDS
INCREASING FROM THE W/SW TO 15-25 KT. THIS WILL ALLOW WAVES ACROSS
THE NORTHERN TIER OF LAKE MICHIGAN TO BUILD TONIGHT. THEN ANOTHER
BOUNDARY WILL SLIDE ACROSS THE LAKE SUNDAY THAT WILL ONCE AGAIN
ALLOW WINDS TO TURN NORTHWEST. WITH COLD AIR FLOWING OVER LAKE
MICHIGAN...WAVES SHOULD EASILY BUILD LATER IN THE WEEKEND. THEN
YET ANOTHER AREA OF HIGH PRESSURE APPEARS TO BUILD INTO THE REGION
EARLY IN THE UPCOMING WEEK...WHICH SHOULD ALLOW WINDS TO DIMINISH
MONDAY TO AROUND 10-20 KT BEFORE INCREASING AHEAD OF YET ANOTHER
WEAK LOW PRESSURE AND FRONTAL BOUNDARY.
CONFIDENCE...MEDIUM/LOW.
BEACHLER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 4 PM SATURDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1157 AM CST SAT NOV 24 2012
.DISCUSSION...
ISSUED 1030 AM CST SAT NOV 24 2012
UPDATED THE FORECAST TODAY FOR DECREASING LOW CLOUDS OVER EAST
CENTRAL IL AND ALONG THE WABASH RIVER VALLEY IN SOUTHEAST IL TODAY.
ALSO HAVE INCREASING MID/HIGHL CLOUDS OVER WESTERN AND CENTRAL IL
DURING THIS AFTERNOON. SO VARIABLE CLOUD COVER ACROSS CENTRAL AND
SE IL TODAY. ANOTHER CHILLY LATE FALL DAY WITH HIGHS IN THE MID TO
UPPER 30S. BUT LIGHTER NW WINDS OF 5 TO 10 MPH TODAY AS HIGH
PRESSURE RIDGE DRIFTS EAST FROM THE MS VALLEY ACROSS IL DURING
THIS AFTERNOON.
LOW STRATOCUMULUS CLOUD DECK WITH CEILING FROM 1500-2500 FT DRIFTED
SOUTHWARD ACROSS EASTERN IL THIS MORNING AND CURRENTLY EXTEND
ALONG AND EAST OF A LACON TO LINCOLN TO EFFINGHAM TO OLNEY LINE.
THESE CLOUDS BLANKET MUCH OF IN/MI AND EASTERN WI TOO. MEANWHILE MID/HIGH
CLOUDS ABOVE 8K FT WERE OVER MUCH OF IA/MO AND THE CENTRAL/NORTHERN
PLAINS AND DRIFTING SE TOWARD WEST CENTRAL IL WITH CIRRUS CLOUDS
20-25K FT OVER MO AND SW IL. 10 AM TEMPS WERE IN THE MID TO UPPER
20S WITH OLNEY AND SPRINGFIELD UP TO 30F. DEWPOINTS WERE IN THE
UPPER TEENS TO AROUND 20F. WNW WINDS LESS THAN 10 MPH PREVAILED
THIS MORNING.
1031 MB HIGH PRESSURE OVER EAST TEXAS AND RIDGING ACROSS THE MS
VALLEY WILL SETTLE ACROSS THE GULF COAST STATES BY 06Z/MIDNIGHT
TONIGHT AND RIDGING NORTHWARD INTO THE TN/OH VALLEYS. RIDGE AXIS
TO DRIFT EAST OF IL BY SUNSET WITH WNW WINDS UNDER 10 MPH TURNING
SSW LATE TODAY AND EVENING. 850 MB TEMPS OF MINUS 4-6C AT 12Z MODIFY
FROM SW TO NE DURING THE AFTERNOON REACHING MINUS 3C TO 1C BY
SUNSET BUT LIMITED SURFACE WARM AIR ADVECTION PLUS SOME CLOUD
COVER AND COLD START TO DAY WILL KEEP HIGHS IN THE MID TO UPPER
30S WITH MILDEST READINGS FROM SPRINGFIELD SW.
07
&&
.AVIATION...
ISSUED 1155 AM CST SAT NOV 24 2012
MVFR BROKEN TO OVERCAST CEILINGS 1.5-2K FT FROM STRATOCUMULUS DECK
OVER EASTERN IL AT CMI WILL SCATTERED OUT BY MID AFTERNOON AS DEC
RECENTLY HAS SCATTERED OUT AND BMI WILL TOO IN THE NEXT HOUR.
MEANWHILE BROKEN TO TO OVERCAST MID/HIGH CLOUDS ABOVE 8K FT OVER
IA AND WEST CENTRAL IL WILL SPREAD INTO CENTRAL IL FROM WEST TO
EAST DURING THE AFTERNOON AND REMAIN IN PLACE TONIGHT AND SUNDAY
MORNING. AIRMASS QUITE DRY WITH DEWPOINTS IN THE UPPER TEENS TO
AROUND 20F SO NO FOG EXPECTED NEXT 24 HOURS. THOUGH DEC HAD MVFR
VSBYS 4-5 MILES WITH HAZE THIS MORNING BUT VSBY HAS RECENTLY ROSE
TO 7 MILES. 1030 MB HIGH PRESSURE OVER EAST TX AND RIDGING ACROSS
THE MS VALLEY WILL DRIFT EAST ACROSS THE SOUTHEAST STATES BY
18Z/NOON SUNDAY. WSW WINDS 5-9 KTS THIS AFTERNOON TO TURN SOUTH
THIS EVENING AND THEN W/SW 9-13 KTS SUNDAY MORNING AS A WEAKENING
FRONT MOVES INTO CENTRAL IL BY MIDDAY SUNDAY.
07
&&
.PREV DISCUSSION...
ISSUED 225 AM CST SAT NOV 24 2012
LATEST SURFACE MAP SHOWING HIGH PRESSURE RIDGE EXTENDING FROM
OKLAHOMA NORTHWARD INTO MINNESOTA. WIDESPREAD STRATOCUMULUS IN THE
CYCLONIC FLOW OVER THE GREAT LAKES HAS PUSHED SOUTHWARD TO ABOUT A
PONTIAC TO PARIS LINE AS OF 2 AM. LARGE SHIELD OF MID AND HIGH
CLOUDS ALSO DROPPING SOUTHEAST FROM THE NORTHERN AND CENTRAL PLAINS.
THE PRIMARY FORECAST CONCERN INVOLVES THE PRECIPITATION POTENTIAL
MONDAY AND MONDAY NIGHT...INCLUDING ANY WINTER PRECIP TYPES...AS A
STORM SYSTEM PASSES TO OUR SOUTH.
SHORT TERM...TODAY THROUGH MONDAY NIGHT...
LATEST RAP MODEL AND VAD WIND PROFILES AT 925 MB SUGGEST THE
LOWER CLOUDS SHOULD NOT MAKE MUCH FURTHER WESTWARD PROGRESS...AND
BEGIN TO PULL EASTWARD LATER THIS MORNING. HIGH CLOUDS STREAMING
IN FROM THE NORTHWEST WILL YIELD PARTLY TO MOSTLY SUNNY CONDITIONS
TODAY. TEMPERATURES EXPECTED TO REMAIN RATHER CHILLY TODAY WITH
MID TO UPPER 30S COMMON...AS THE RIDGE AXIS MOVES OVERHEAD.
RETURN FLOW EXPECTED TO BEGIN SETTING UP AROUND SUNSET.
TEMPERATURES ACROSS THE WESTERN CWA EXPECTED TO LEVEL OFF BY
MIDNIGHT...AND PERHAPS RISE A COUPLE DEGREES LATE. HIGHS ON SUNDAY
SHOULD BE ABOUT 10-15 DEGREES WARMER.
LARGE UPPER TROUGH OVER THE EASTERN CONUS TO BREAK DOWN THIS
WEEKEND AS SOME AMPLIFICATION TAKES PLACE ALONG THE WEST COAST.
FAST MOVING JET STREAK OF AROUND 75 KNOTS AT 500 MB WILL PUSH A
BOUNDARY ACROSS THE CWA ON SUNDAY...BUT CLOUDS WILL BE THE MAIN
EFFECT FROM IT. OF MORE CONCERN IS A STORM SYSTEM DEVELOPING ALONG
THE TEXAS/OKLAHOMA BORDER LATE SUNDAY NIGHT AND MONDAY. WHILE THE
EVENING MODELS ALL KEEP THE PARENT SURFACE LOW WELL TO OUR
SOUTH...MOISTURE WILL BE DRAWN NORTH AS A SHORTWAVE IN THE
NORTHERN JET STREAM MOVES INTO THE PLAINS. GFS/CANADIAN MODELS
DRAW THE PRECIPITATION AS FAR NORTH AS ABOUT THE I-72 CORRIDOR BY
MONDAY EVENING...WHILE THE NAM/ECMWF MODELS KEEP ALL THE PRECIP TO
OUR SOUTH. THESE LATTER MODELS MAY BE A LITTLE ON THE FASTER
SIDE...ESPECIALLY THE ECMWF...SO WILL LEAN MORE TOWARD THE SLOWER
SOLUTIONS. AS SUCH...WILL HAVE THE HIGHEST POPS ACROSS THE
SOUTHEAST CWA...ESPECIALLY MONDAY AFTERNOON AND NIGHT. FORECAST
SOUNDINGS INDICATE A RAIN TO SNOW TRANSITION MONDAY EVENING ACROSS
THE SOUTHEAST CWA AND LIGHT SNOW ELSEWHERE...BUT A PERSISTENT DRY
NORTHEAST FLOW WILL KEEP PRECIP TOTALS DOWN. HAVE KEPT AREAS
NORTHWEST OF THE ILLINOIS RIVER WITH MAINLY SLIGHT CHANCE
POPS...WHERE HIGH PRESSURE WILL BUILD IN TO THE AREA.
LONG TERM...TUESDAY THROUGH FRIDAY...
MAINLY QUIET CONDITIONS EXPECTED DURING THIS TIME FRAME. UPPER
RIDGING OVER THE WESTERN U.S. SHOULD TRANSITION TO MORE OF A ZONAL
FLOW AS THE WEEK PROGRESSES...WITH MODERATING TEMPERATURES. LONGER
RANGE MODELS PUSH A FAST MOVING SHORTWAVE THROUGH THE STATE LATE
THURSDAY NIGHT OR EARLY FRIDAY. THE GFS IS THE WETTER OF THE
MODELS WITH THIS FEATURE BUT MAINLY KEEPS THE PRECIPITATION JUST
TO OUR NORTH...SO WILL KEEP THE EXTENDED FORECAST DRY.
GEELHART
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1137 AM CST SAT NOV 24 2012
.DISCUSSION...
930 AM CST
HAVE MADE SOME ADJUSTMENTS TO THE FORECAST TO HOLD ONTO CLOUDS
LONGER...PARTICULARLY ACROSS NORTHEAST IL AND NORTHWEST IN...AND
ACCORDINGLY HAVE LOWERED FORECAST HIGH TEMPS BY A COUPLE DEGREES
IN PLACES.
THE GOES WATER VAPOR LOOP THIS MORNING IS REFLECTING DRYING MOVING
EASTWARD OVER THE AREA...AND REGIONAL SOUNDINGS REFLECTED THAT IN
THE MID-LEVELS. HOWEVER...HEIGHT RISES AT 700 MB WERE NEUTRAL THIS
MORNING INDICATING LIMITED OVERALL SUPPRESSION...AS WAS 700 TO
850 MB TEMPERATURE ADVECTION /DVN AND GRB EVEN COOLED AT 700 MB/.
WITH PROFILERS ALSO INDICATING MORE OF A NORTHERLY FLOW IN THE
LOW-LEVELS...GENERAL CYCLONIC FLOW APPEARS TO BE HANGING ON
LONGER THAN INITIAL THOUGHT...ESPECIALLY ACROSS EASTERN AREAS.
THIS REGIME WILL NOT AID THE CLOUDS IN CLEARING THROUGH EARLY
AFTERNOON...EVEN WITH THE MOIST LAYER AT THE CLOUD HEIGHT
REMAINING SHALLOW /1000 FT OR LESS/ ON AMDAR SOUNDINGS AND THE GRB
RAOB THIS MORNING. ADAPTING AN AREA AMDAR SOUNDING IT WOULD SEEM
THAT SURFACE TEMPS IN THE MID 30S WOULD BE NEEDED TO MIX OUT SOME
OF THE CLOUD COVER...AND WITH NO WARMING HAPPENING UNDER THE HEART
OF THE CLOUDS AND MUCH LOWER STARTING TEMPERATURES THIS MORNING AT
THE PERIPHERY OF THE CLOUD SHIELD...DO NOT SEE THIS HAPPENING
ANYTIME SOON. SO OUTSIDE OF A COUPLE HOLES FROM THE WEAK TO
SUPPRESSION ALOFT...THE CLOUD SHIELD SHOULD ONLY OOZE ITS WAY
EAST THROUGH EARLY AFTERNOON THEN INCREASE IN SPEED WITH THE WARM
AIR ADVECTION PATTERN. EVEN AT 3 PM THOUGH...PARCEL TRAJECTORIES
OVER EASTERN AREAS ARE FROM CLOUD COVERED SOUTH CENTRAL WI AT
PRESENT. THE RAP 900 MB RH FORECAST SEEMS TO CAPTURE THE EVOLUTION
WELL...AND IS IN GOOD AGREEMENT WITH THE NARRE-TL CLOUD FORECAST.
SO HAVE COLLABORATED THESE IDEAS INTO THE CLOUD COVER FORECAST
AND KEPT TEMPERATURES CLIMBING AT ABOUT 1 DEGREE PER TWO HOURS
ACROSS THE EAST THROUGH EARLY AFTERNOON. OVERALL THIS TOOK HIGHS
DOWN 1 TO 3 DEGREES IN PLACES.
MTF
//PREV DISCUSSION...
352 AM CST
FOLLOWING AN ACTIVE HOLIDAY WEEK WITH DENSE FOG THANKSGIVING EVE
MORNING FOLLOWED BY NEAR RECORD WARMTH ON THANKSGIVING DAY... AND
THEN A JOLT BACK TO REALITY COURTESY OF A STRONG COLD FRONT ON
BLACK FRIDAY... THE COMING WEEKEND WILL BE RELATIVELY QUIET WITH
CHILLY DAYTIME HIGHS SATURDAY ONLY IN THE 30S... WITH MAX TEMPS
SUNDAY RETURNING TO AROUND SEASONAL NORMS.
AS DEEP SURFACE LOW PRESSURE OVER QUEBEC CONTINUES TO PUSH NE AWAY
FROM THE GREAT LAKES... RIDGING WILL BUILD QUICKLY INTO NRN IL/NW IN
THIS MORNING. THE STRENGTHENING ANTI-CYCLONIC FLOW COMBINED WITH
INCREASED SUBSIDENCE THROUGH THE MID LEVELS SHOULD DRY OUT STUBBORN
LINGERING SC FAIRLY QUICKLY FROM WEST TO EAST THROUGH THE MID
MORNING HOURS. DESPITE SUNSHINE THROUGH THE REMAINDER OF THE DAY...
TEMPS WILL ONLY RISE INTO THE MID 30S WITH COLD AIR AT 850 MB
HANGING AROUND UNTIL THE BETTER WARM AID ADVECTION (WAA) PATTERN
SETS UP ACROSS THE AREA THIS EVENING.
WITH LOW LEVEL WAA COMBINED WITH RISING HEIGHTS ALOFT EXPECT MIN
TEMPS TONIGHT TO BE REALIZED THIS EVENING WITH TEMPS THEN STEADYING
OUT BY LATE EVENING AND PROBABLY EVEN RISING A FEW DEGREES DURING
THE OVERNIGHT. EXPECT CLOUDS TO INCREASE AHEAD OF A FAIRLY POTENT
SECONDARY SHORTWAVE TROUGH DROPPING INTO THE UPPER GREAT LAKES
TONIGHT INTO EARLY SUNDAY. ANY FORCING OF CONSEQUENCE REMAINS NORTH
OF THE LOCAL AREA HOWEVER AND HENCE EXPECT PRECIP TO DO LIKEWISE.
SUNDAY SHAPING UP TO BE A FAIRLY TYPICAL LATE NOVEMBER DAY WITH
CLOUDS GIVING WAY TO SOME SUN AND TEMPS TOPPING OUT IN THE MID 40S.
A WEAK COLD FRONT ASSOCIATED WITH AFOREMENTIONED UPPER SHORTWAVE
TROUGH WILL SWEEP ACROSS THE REGION DURING THE AFTERNOON BUT SHOULD
RESULT IN LITTLE MORE THAN A WIND SHIFT AS COLDEST CORE OF AIR
BEHIND IT WILL REMAIN TO OUR NORTH.
MODELS CONTINUE TO TREND FARTHER SOUTH WITH LOW PRESSURE DEVELOPING
OVER THE SOUTHERN PLANS ON MONDAY AND THEN TRACKING ACROSS THE LOWER
MISSISSIPPI VALLEY MONDAY NIGHT AND ACROSS THE SOUTH ON TUES. WITH
THIS TREND BECOMING MORE PRONOUNCED... WILL CONTINUE PREVIOUS
FORECAST TREND OF LOWERING POPS ACROSS THE CWFA ANOTHER NOTCH FOR
THE MON NIGHT-TUES TIME PERIOD. SHOULD THIS MORE SOUTHERN TRACK
VERIFY... AT LEAST THE NORTHERN 2/3 OF THE CWFA IF NOT THE ENTIRE
AREA WILL PROBABLY SEE NO PRECIP AT ALL... HOWEVER GIVEN SOME
UNCERTAINTY REMAINING IN THE ENSEMBLE SPREAD... WOULD LIKE TO SEE
ANOTHER MODEL RUN BEFORE PULLING COMPLETELY.
A DRY NORTHWESTERLY FLOW ALOFT SETS UP FOR WED AND THURS WITH
BROAD HIGH PRESSURE DOMINATING AT THE SURFACE AND SEASONAL TEMPS.
THEN LEE SIDE CYCLOGENEIS DEVELOPS IN RESPONSE TO AN UPPER LEVEL
TROUGH MOVING INTO THE CENTRAL PLAINS LATER ON THURSDAY AND MOVES
INTO THE LOCAL AREA LATE THURSDAY NIGHT INTO FRIDAY. HAVE
INTRODUCED LOW POPS WITH THIS FEATURE AS DYNAMICS INITIALLY
APPEAR REASONABLY IMPRESSIVE HOWEVER AT DAYS 6-7 WOULD LIKE TO
SEE GREATER MODEL CONSISTENCY BEFORE INTRODUCING MENTION OF
ANYTHING MORE THAN A SLIGHT CHANCE OF PRECIP. THE AIR MASS IN
PLACE AT THE TIME WILL BE SUFFICIENTLY COLD ENOUGH TO SUPPORT A
MIX OF RAIN AND SNOW INITIALLY EARLY FRIDAY BEFORE INCREASING WAA
WARMS THE COLUMN TO AT OR ABOVE THE FREEZING MARK.
ED F
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* LIGHT WEST WINDS BECOMING LIGHT SOUTHWEST BY LATE AFTERNOON.
* CEILINGS AT 2500-3000 FT BECOMING SCATTERED CLOUDS BY 19Z.
PAW
//DISCUSSION...UPDATED 18Z...
HIGH PRESSURE IS BUILDING INTO NORTHERN ILLINOIS AND NORTHWEST
INDIANA AT MIDDAY. THIS IS FINALLY ERODING THE CLOUD DECK THAT
HAS PERSISTED THROUGH THE MORNING. HOWEVER THE CLEARING WILL BE
SHORT LIVED AS MIDDLE AND HIGH LEVEL CLOUDS AHEAD OF AN
APPROACHING UPPER LEVEL TROUGH ARE ALREADY INTO EASTERN IA AND
MOVING TO THE EAST. THESE VFR-LEVEL WILL CEILINGS TO MOVE INTO
ALL THE TERMINALS LATE THIS AFTERNOON INTO THE EVENING HOURS. THE
TROUGH HAS LIMITED MOISTURE TO WORK WITH...SO NOT EXPECTING ANY
PRECIPITATION WITH IT. THE BIGGEST IMPACT WILL BE TO SHIFT THE
WINDS TO THE NORTHWEST AND SCATTER OUT THE CEILINGS AS IT MOVES
ACROSS THE AREA ON SUNDAY.
PAW
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH CONFIDENCE IN WIND TREND.
* HIGH CONFIDENCE IN CEILING TREND AND TIMING.
PAW
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT...VFR.
MONDAY...VFR. CHC OF LGT SN AND MVFR IN THE EVENING.
TUESDAY...CHC OF MVFR EARLY...TRENDING VFR LATE.
WEDNESDAY THROUGH THURSDAY...VFR.
FRIDAY...VFR. SLIGHT CHC LGT RA/SN AND PATCHY MVFR.
BEACHLER
&&
.MARINE...
258 AM CST
OCCASIONAL GALES CONTINUE ACROSS THE NORTHERN HALF OF LAKE MICHIGAN
EARLY THIS MORNING...HOWEVER THE FREQUENCY CONTINUES TO DIMINISH.
THUS IT APPEARS THE GALE WARNING WILL BE ALLOWED TO EXPIRE AT
ISSUANCE OF THE NEW GLF. WILL MENTION AN OCCASIONAL GALE FORCE GUST
TO 35 KT THROUGH DAYBREAK. THEN EXPECT WINDS TO STEADILY DIMINISH.
HIGH PRESSURE WILL BEGIN TO BUILD IN FROM THE WEST...WHICH WILL
ALLOW WINDS TO FURTHER DIMINISH AND BECOME WESTERLY THIS
AFTERNOON. WILL CONTINUE TO FEATURE THE SMALL CRAFT ADVISORY
THROUGH EARLY THIS AFTERNOON...POSSIBLY ENDING EARLIER FOR THE
ILLINOIS NEARSHORE WATERS. WINDS WILL CONTINUE TO DIMINISH
THROUGHOUT THE AFTERNOON AND EARLY EVENING...HOWEVER THE HIGH
PRESSURE WILL QUICKLY DRIFT SOUTHEAST OF THE REGION. THIS WILL
ALLOW ANOTHER TIGHT GRADIENT TO RETURN LATE TONIGHT WITH WINDS
INCREASING FROM THE W/SW TO 15-25 KT. THIS WILL ALLOW WAVES ACROSS
THE NORTHERN TIER OF LAKE MICHIGAN TO BUILD TONIGHT. THEN ANOTHER
BOUNDARY WILL SLIDE ACROSS THE LAKE SUNDAY THAT WILL ONCE AGAIN
ALLOW WINDS TO TURN NORTHWEST. WITH COLD AIR FLOWING OVER LAKE
MICHIGAN...WAVES SHOULD EASILY BUILD LATER IN THE WEEKEND. THEN
YET ANOTHER AREA OF HIGH PRESSURE APPEARS TO BUILD INTO THE REGION
EARLY IN THE UPCOMING WEEK...WHICH SHOULD ALLOW WINDS TO DIMINISH
MONDAY TO AROUND 10-20 KT BEFORE INCREASING AHEAD OF YET ANOTHER
WEAK LOW PRESSURE AND FRONTAL BOUNDARY.
CONFIDENCE...MEDIUM/LOW.
BEACHLER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 4 PM SATURDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1030 AM CST SAT NOV 24 2012
.DISCUSSION...
ISSUED 1030 AM CST SAT NOV 24 2012
UPDATED THE FORECAST TODAY FOR DECREASING LOW CLOUDS OVER EAST
CENTRAL IL AND ALONG THE WABASH RIVER VALLEY IN SOUTHEAST IL TODAY.
ALSO HAVE INCREASING MID/HIGHL CLOUDS OVER WESTERN AND CENTRAL IL
DURING THIS AFTERNOON. SO VARIABLE CLOUD COVER ACROSS CENTRAL AND
SE IL TODAY. ANOTHER CHILLY LATE FALL DAY WITH HIGHS IN THE MID TO
UPPER 30S. BUT LIGHTER NW WINDS OF 5 TO 10 MPH TODAY AS HIGH
PRESSURE RIDGE DRIFTS EAST FROM THE MS VALLEY ACROSS IL DURING
THIS AFTERNOON.
LOW STRATOCUMULUS CLOUD DECK WITH CEILING FROM 1500-2500 FT DRIFTED
SOUTHWARD ACROSS EASTERN IL THIS MORNING AND CURRENTLY EXTEND
ALONG AND EAST OF A LACON TO LINCOLN TO EFFINGHAM TO OLNEY LINE.
THESE CLOUDS BLANKET MUCH OF IN/MI AND EASTERN WI TOO. MEANWHILE MID/HIGH
CLOUDS ABOVE 8K FT WERE OVER MUCH OF IA/MO AND THE CENTRAL/NORTHERN
PLAINS AND DRIFTING SE TOWARD WEST CENTRAL IL WITH CIRRUS CLOUDS
20-25K FT OVER MO AND SW IL. 10 AM TEMPS WERE IN THE MID TO UPPER
20S WITH OLNEY AND SPRINGFIELD UP TO 30F. DEWPOINTS WERE IN THE
UPPER TEENS TO AROUND 20F. WNW WINDS LESS THAN 10 MPH PREVAILED
THIS MORNING.
1031 MB HIGH PRESSURE OVER EAST TEXAS AND RIDGING ACROSS THE MS
VALLEY WILL SETTLE ACROSS THE GULF COAST STATES BY 06Z/MIDNIGHT
TONIGHT AND RIDGING NORTHWARD INTO THE TN/OH VALLEYS. RIDGE AXIS
TO DRIFT EAST OF IL BY SUNSET WITH WNW WINDS UNDER 10 MPH TURNING
SSW LATE TODAY AND EVENING. 850 MB TEMPS OF MINUS 4-6C AT 12Z MODIFY
FROM SW TO NE DURING THE AFTERNOON REACHING MINUS 3C TO 1C BY
SUNSET BUT LIMITED SURFACE WARM AIR ADVECTION PLUS SOME CLOUD
COVER AND COLD START TO DAY WILL KEEP HIGHS IN THE MID TO UPPER
30S WITH MILDEST READINGS FROM SPRINGFIELD SW.
07
&&
.AVIATION...
ISSUED 503 AM CST SAT NOV 24 2012
A LARGE AREA OF MVFR CLOUDS IS AFFECTING BMI AND CMI THIS MORNING.
BASED ON SATELLITE TRENDS...APPEARS THIS CLOUD DECK WILL NOT GET
ANY FURTHER WEST THIS MORNING...THOUGH IT IS COMING CLOSE TO DEC
AND PIA. MODELS DO NOT HAVE A GOOD HANDLE ON THIS LOW LEVEL
MOISTURE AT THIS TIME...SO WILL TRY TO FORECAST CLEARING AT BMI
AND PIA BASED ON SHIFTING OF HIGH PRSS RIDGE...WHICH SHOULD BE
SOMETIME LATER THIS MORNING. SPI/PIA/DEC WILL REMAIN CLEAR THIS
MORNING. ALL SITES WILL ALSO SEE AN INCREASE...AND LOWERING...OF
MID CLOUDS THIS AFTERNOON...IN RESPONSE TO THE WAA THAT BEGINS TO
RETURN THIS AFTERNOON ONCE THE HIGH PRSS RIDGE MOVES EAST OF THE
AREA. ONCE THIS MOVES THROUGH...THE HIGH CIRRUS CLOUDS SHOULD BE
THE RULE FOR THE NIGHT. WINDS WILL BE LIGHT WEST-NORTHWESTERLY
THIS MORNING AND THEN BECOME SOUTH-SOUTHWESTERLY THIS AFTERNOON
AND THEN CONTINUE INTO THE NIGHT. WINDS SPEEDS WILL NOT INCREASE
TO AFTER 06Z LATE TONIGHT.
AUTEN
&&
.PREV DISCUSSION...
ISSUED 225 AM CST SAT NOV 24 2012
LATEST SURFACE MAP SHOWING HIGH PRESSURE RIDGE EXTENDING FROM
OKLAHOMA NORTHWARD INTO MINNESOTA. WIDESPREAD STRATOCUMULUS IN THE
CYCLONIC FLOW OVER THE GREAT LAKES HAS PUSHED SOUTHWARD TO ABOUT A
PONTIAC TO PARIS LINE AS OF 2 AM. LARGE SHIELD OF MID AND HIGH
CLOUDS ALSO DROPPING SOUTHEAST FROM THE NORTHERN AND CENTRAL PLAINS.
THE PRIMARY FORECAST CONCERN INVOLVES THE PRECIPITATION POTENTIAL
MONDAY AND MONDAY NIGHT...INCLUDING ANY WINTER PRECIP TYPES...AS A
STORM SYSTEM PASSES TO OUR SOUTH.
SHORT TERM...TODAY THROUGH MONDAY NIGHT...
LATEST RAP MODEL AND VAD WIND PROFILES AT 925 MB SUGGEST THE
LOWER CLOUDS SHOULD NOT MAKE MUCH FURTHER WESTWARD PROGRESS...AND
BEGIN TO PULL EASTWARD LATER THIS MORNING. HIGH CLOUDS STREAMING
IN FROM THE NORTHWEST WILL YIELD PARTLY TO MOSTLY SUNNY CONDITIONS
TODAY. TEMPERATURES EXPECTED TO REMAIN RATHER CHILLY TODAY WITH
MID TO UPPER 30S COMMON...AS THE RIDGE AXIS MOVES OVERHEAD.
RETURN FLOW EXPECTED TO BEGIN SETTING UP AROUND SUNSET.
TEMPERATURES ACROSS THE WESTERN CWA EXPECTED TO LEVEL OFF BY
MIDNIGHT...AND PERHAPS RISE A COUPLE DEGREES LATE. HIGHS ON SUNDAY
SHOULD BE ABOUT 10-15 DEGREES WARMER.
LARGE UPPER TROUGH OVER THE EASTERN CONUS TO BREAK DOWN THIS
WEEKEND AS SOME AMPLIFICATION TAKES PLACE ALONG THE WEST COAST.
FAST MOVING JET STREAK OF AROUND 75 KNOTS AT 500 MB WILL PUSH A
BOUNDARY ACROSS THE CWA ON SUNDAY...BUT CLOUDS WILL BE THE MAIN
EFFECT FROM IT. OF MORE CONCERN IS A STORM SYSTEM DEVELOPING ALONG
THE TEXAS/OKLAHOMA BORDER LATE SUNDAY NIGHT AND MONDAY. WHILE THE
EVENING MODELS ALL KEEP THE PARENT SURFACE LOW WELL TO OUR
SOUTH...MOISTURE WILL BE DRAWN NORTH AS A SHORTWAVE IN THE
NORTHERN JET STREAM MOVES INTO THE PLAINS. GFS/CANADIAN MODELS
DRAW THE PRECIPITATION AS FAR NORTH AS ABOUT THE I-72 CORRIDOR BY
MONDAY EVENING...WHILE THE NAM/ECMWF MODELS KEEP ALL THE PRECIP TO
OUR SOUTH. THESE LATTER MODELS MAY BE A LITTLE ON THE FASTER
SIDE...ESPECIALLY THE ECMWF...SO WILL LEAN MORE TOWARD THE SLOWER
SOLUTIONS. AS SUCH...WILL HAVE THE HIGHEST POPS ACROSS THE
SOUTHEAST CWA...ESPECIALLY MONDAY AFTERNOON AND NIGHT. FORECAST
SOUNDINGS INDICATE A RAIN TO SNOW TRANSITION MONDAY EVENING ACROSS
THE SOUTHEAST CWA AND LIGHT SNOW ELSEWHERE...BUT A PERSISTENT DRY
NORTHEAST FLOW WILL KEEP PRECIP TOTALS DOWN. HAVE KEPT AREAS
NORTHWEST OF THE ILLINOIS RIVER WITH MAINLY SLIGHT CHANCE
POPS...WHERE HIGH PRESSURE WILL BUILD IN TO THE AREA.
LONG TERM...TUESDAY THROUGH FRIDAY...
MAINLY QUIET CONDITIONS EXPECTED DURING THIS TIME FRAME. UPPER
RIDGING OVER THE WESTERN U.S. SHOULD TRANSITION TO MORE OF A ZONAL
FLOW AS THE WEEK PROGRESSES...WITH MODERATING TEMPERATURES. LONGER
RANGE MODELS PUSH A FAST MOVING SHORTWAVE THROUGH THE STATE LATE
THURSDAY NIGHT OR EARLY FRIDAY. THE GFS IS THE WETTER OF THE
MODELS WITH THIS FEATURE BUT MAINLY KEEPS THE PRECIPITATION JUST
TO OUR NORTH...SO WILL KEEP THE EXTENDED FORECAST DRY.
GEELHART
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
545 PM EST SAT NOV 24 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 324 PM EST SAT NOV 24 2012
DRY CONDITIONS WILL PERSIST INTO MONDAY AS HIGH PRESSURE PASSES TO
THE SOUTH OF THE REGION. A SURFACE LOW WILL TRACK ALONG A REMNANT
COLD FRONT THROUGH THE TENNESSEE VALLEY MONDAY NIGHT. MOISTURE
ASSOCIATED WITH THE LOW WILL LOFT INTO THE REGION...BRINGING CLOUDS
AND LIGHT RAIN CHANGING TO SNOW. COLD DRY WEATHER WILL RETURN FOR
MUCH OF THE REST OF THE WEEK AS BROAD HIGH PRESSURE BUILDS ACROSS
THE OHIO VALLEY.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 324 PM EST SAT NOV 24 2012
TEMPS HAVE BEEN HELD DOWN SO FAR TODAY AS EXTENSIVE STRATOCU DECK
REMAINS ACROSS MOST OF THE FORECAST AREA. AT 19Z...TEMPERATURES
RANGED FROM THE UPPER 20S TO LOWER 30S ACROSS THE REGION.
STRATOCU DECK IS THE INITIAL FOCUS OF THE FORECAST. VISIBLE
SATELLITE SHOWING EROSION OF THE STRATOCU ACROSS THE WABASH VALLEY
OVER THE LAST HOUR OR TWO AS LOW LEVEL FLOW BACKING IN RESPONSE TO
THE ARRIVAL OF THE RIDGE AXIS. EXPECT LOW CLOUDS TO GRADUALLY THIN
FROM THE WEST THROUGH THE REMAINDER OF THE AFTERNOON WITH SOME
SUNSHINE ANTICIPATED WEST OF I-65 PRIOR TO SUNSET. FURTHER
EAST...STRATOCU APPEARS MORE FIRMLY ENTRENCHED ON BACK SIDE OF DEEP
UPPER TROUGH. HAVE TRENDED TOWARDS RAP 900-925MB RH PROGS WHICH KEEP
CLOUDS INTO THE EVENING BEFORE THEY GIVE WAY FROM THE WEST.
ANY CLEARING HOWEVER IS LIKELY TO BE TEMPORARY ACROSS THE FORECAST
AREA AS MID AND HIGH LEVEL CLOUDS ARE ALREADY RAPIDLY EXPANDING EAST
ACROSS THE MID MISSISSIPPI VALLEY AND WILL ENCOMPASS THE REGION
OVERNIGHT. DEEP MOISTURE PRESENT ABOVE 600MB AFTER MIDNIGHT WITH
ISENTROPIC LIFT NOTED AT 300K AND HIGHER ALL SUGGESTIVE OF FAIRLY
DENSE CLOUD COVER LATE TONIGHT...ESPECIALLY OVER THE NORTHERN HALF
OF THE FORECAST AREA.
TEMPS...ENDED UP NEAR MAVMOS FOR LOWS OVERNIGHT AS COOLER THAN
EXPECTED TEMPS TODAY COUNTERACT POTENTIAL FOR TEMPS TO STAY UP WITH
CLOUDS TONIGHT. SHOULD END UP IN THE MID 20S MOST PLACES OVERNIGHT.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY/...
ISSUED AT 324 PM EST SAT NOV 24 2012
FORECAST CHALLENGES FOCUS ON PRECIP CHANCES AND TYPE WITH SURFACE
WAVE TRACKING THROUGH THE TENNESSEE VALLEY MONDAY NIGHT.
COLD FRONT WILL DROP SOUTH INTO THE REGION DURING THE DAY SUNDAY...
MAINTAINING MID AND HIGH LEVEL CLOUDS ACROSS THE NORTHERN HALF OF
THE FORECAST AREA. MODEL SOUNDINGS CONTINUE TO SHOW AN AXIS OF DEEP
MOISTURE ABOVE 10KFT AHEAD OF THE FRONT...GRADUALLY SHIFTING NORTH
BY LATE AFTERNOON AND EVENING AS MOISTURE PROFILES DECREASE AND
BOUNDARY LOSES ITS SURFACE CHARACTERISTICS AS IT SLIDES SOUTH.
WHATS LEFT OF THE BOUNDARY WILL SHIFT SOUTH OF THE OHIO RIVER ON
MONDAY AND BECOME NEARLY STATIONARY AS A SURFACE WAVE DEVELOPS OVER
TEXAS AND TRACKS NORTHEAST ALONG IT. MODEL CONSENSUS OVER THE LAST
COUPLE DAYS CONTINUE TO SHIFT THE TRACK OF THE LOW AND POSITION OF
THE BOUNDARY STEADILY SOUTH INTO THE TENNESSEE VALLEY BY LATE
MONDAY...LIKELY DUE AS MODELS CAPTURE THE STRENGTH OF THE
APPROACHING HIGH OVER THE NORTHERN PLAINS TO A GREATER DEGREE. THE
FURTHER SOUTH TRACK TO THIS SYSTEM IS PRESENTING SOME CHANGES NOT
ONLY IN THE AMOUNT OF PRECIPITATION BUT ALSO IN POTENTIAL PRECIP
TYPE AS COLDER AIR FILTERS INTO CENTRAL INDIANA MUCH QUICKER ON
MONDAY NIGHT.
HAVE LEANED TOWARDS THE CONSENSUS APPROACH BEING OFFERED BY THE
ECMWF/OP GFS/SREF WHICH BRING THE MOISTURE PLUME NORTH INTO THE OHIO
VALLEY LATE MONDAY AFTERNOON AHEAD OF THE UPPER LEVEL TROUGH AND
NORTH OF THE SURFACE WAVE...SPREADING EAST ACROSS THE REGION MONDAY
NIGHT. BEST ISENTROPIC LIFT NOW CONFINED TO MAINLY SOUTHERN PORTIONS
OF THE FORECAST AREA MONDAY NIGHT...AND EXPECT THE MOST WIDESPREAD
PRECIPITATION WILL SET UP FROM FAR SOUTHERN COUNTIES SOUTH INTO
KENTUCKY. FURTHER NORTH WHERE MOISTURE PROFILES ARE NOT AS
IMPRESSIVE...EXPECT LIGHTER PRECIP TO THE TUNE OF LESS THAN A TENTH
OF AN INCH. ANALYSIS OF MODEL SOUNDINGS AND LOW LEVEL THICKNESSES
SUGGESTIVE OF MAINLY LIGHT SNOW ALONG AND NORTH OF I-70 MONDAY
EVENING...WITH RAIN GRADUALLY MIXING WITH AND CHANGING OVER TO LIGHT
SNOW FURTHER SOUTH AS THE NIGHT WEARS ON. SOME HINTS OF A BAND OF
ENHANCED PRECIP SETTING UP NEAR OR JUST SOUTH OF THE FORECAST AREA
LATE MONDAY NIGHT AND SHOULD THE COLDER AIR ARRIVE FAST ENOUGH...
COULD SEE A QUICK BURST OF SNOW WITH A POSSIBLE ACCUM OF A FEW
TENTHS ACROSS FAR SOUTHERN COUNTIES BEFORE THE BETTER LIFT SHIFTS
EAST AROUND DAYBREAK TUESDAY. WITH THE CONSISTENT SHIFT SOUTH OF THE
TRACK OF THE SURFACE LOW THE LAST FEW DAYS...CONFIDENCE IS LOW ON
WHETHER THAT BAND OF ENHANCED PRECIP WILL SET UP OVER FAR SOUTHERN
COUNTIES OR IF ITS CLOSER TO THE OHIO RIVER. ANY LINGERING PRECIP
WILL END TUESDAY MORNING AS THE BROAD HIGH PRESSURE SHIFTS EAST INTO
THE REGION. COLD DRY WEATHER WILL THEN RESUME FOR CENTRAL INDIANA
FOR MIDWEEK.
TEMPS...LEANED TOWARDS COOLER MAVMOS FOR SUNDAY WITH POTENTIAL FOR
MORE CLOUDS ACROSS THE REGION. UNDERCUT MOS ON MONDAY WITH
INCREASING CLOUDS AND NORTHERLY FLOW AND AGAIN TUESDAY WITH COLD
ADVECTION IN WAKE OF THE STORM SYSTEM. NEAR MOS FOR LOWS TONIGHT...
THEN WENT ABOVE GUIDANCE FOR MONDAY NIGHT WITH MOS APPEARING TO
OVERDO THE COLD AIR INTRUSION.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
ISSUED AT 324 PM EST SAT NOV 24 2012
HIGH PRESSURE WILL BE IN CONTROL FOR THE MAJORITY OF THE EXTENDED
PERIOD RESULTING IN A COOL/DRY AIRMASS OVER CENTRAL INDIANA. TEMPS
WILL GRADUALLY WARM THROUGH THE COURSE OF THE PERIOD...AND
INITIALIZATION HAS A GOOD HANDLE ON IT...SO NO DEVIATIONS.
INITIALIZATION IS HINTING AT SOME PRECIP OVER THE NORTHERN PORTIONS
OF THE FORECAST AREA AT THE END OF THE PERIOD AS AN UPPER LEVEL
SHORTWAVE TRAVERSES CENTRAL INDIANA. THERE ARE A LOT OF
DISCREPANCIES IN THE MODELS AT THIS TIME THOUGH...SO WILL NOT MAKE
ANY CHANGES TO LATEST PRECIP INITIALIZATION. THE EURO AND GEM BARELY
HINT AT THE SHORTWAVE ON THURSDAY NIGHT/FRIDAY MORNING...WHILE
THE GFS SHOWS A SOMEWHAT DEVELOPED UPPER LEVEL LOW.
&&
.AVIATION /DISCUSSION FOR THE 25/0000Z TAF ISSUANCE/...
ISSUED AT 545 PM EST SAT NOV 24 2012
STRATOCU DECK SHOULD BE NORTHEAST OF THE TAF SITES BY ISSUANCE TIME
PER MODEL 925 MILLIBAR RH PROGS. MEANWHILE...THICK HIGH AND MID
CLOUDS WILL ALSO BE MOVING IN FROM THE WEST AND COVER THE SKY
THROUGH THE REMAINDER OF THE TAF PERIOD. SOUTH AND SOUTHWEST WINDS 5
KNOTS OR LESS WILL INCREASE TO NEAR 10 KNOTS TOWARD 12Z AND 15 KNOTS
AFTER 15Z WITH GUSTS TO 20 KNOTS OR MORE. WINDS WILL THEN DIMINISH
TO LESS THAN 10 KNOTS AND BECOME SOUTHWEST AND WEST AFTER 21Z BEHIND
A DRY COLD FRONT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM....TDUD
AVIATION...MK
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
330 PM EST SAT NOV 24 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 324 PM EST SAT NOV 24 2012
DRY CONDITIONS WILL PERSIST INTO MONDAY AS HIGH PRESSURE PASSES TO
THE SOUTH OF THE REGION. A SURFACE LOW WILL TRACK ALONG A REMNANT
COLD FRONT THROUGH THE TENNESSEE VALLEY MONDAY NIGHT. MOISTURE
ASSOCIATED WITH THE LOW WILL LOFT INTO THE REGION...BRINGING CLOUDS
AND LIGHT RAIN CHANGING TO SNOW. COLD DRY WEATHER WILL RETURN FOR
MUCH OF THE REST OF THE WEEK AS BROAD HIGH PRESSURE BUILDS ACROSS
THE OHIO VALLEY.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 324 PM EST SAT NOV 24 2012
TEMPS HAVE BEEN HELD DOWN SO FAR TODAY AS EXTENSIVE STRATOCU DECK
REMAINS ACROSS MOST OF THE FORECAST AREA. AT 19Z...TEMPERATURES
RANGED FROM THE UPPER 20S TO LOWER 30S ACROSS THE REGION.
STRATOCU DECK IS THE INITIAL FOCUS OF THE FORECAST. VISIBLE
SATELLITE SHOWING EROSION OF THE STRATOCU ACROSS THE WABASH VALLEY
OVER THE LAST HOUR OR TWO AS LOW LEVEL FLOW BACKING IN RESPONSE TO
THE ARRIVAL OF THE RIDGE AXIS. EXPECT LOW CLOUDS TO GRADUALLY THIN
FROM THE WEST THROUGH THE REMAINDER OF THE AFTERNOON WITH SOME
SUNSHINE ANTICIPATED WEST OF I-65 PRIOR TO SUNSET. FURTHER
EAST...STRATOCU APPEARS MORE FIRMLY ENTRENCHED ON BACK SIDE OF DEEP
UPPER TROUGH. HAVE TRENDED TOWARDS RAP 900-925MB RH PROGS WHICH KEEP
CLOUDS INTO THE EVENING BEFORE THEY GIVE WAY FROM THE WEST.
ANY CLEARING HOWEVER IS LIKELY TO BE TEMPORARY ACROSS THE FORECAST
AREA AS MID AND HIGH LEVEL CLOUDS ARE ALREADY RAPIDLY EXPANDING EAST
ACROSS THE MID MISSISSIPPI VALLEY AND WILL ENCOMPASS THE REGION
OVERNIGHT. DEEP MOISTURE PRESENT ABOVE 600MB AFTER MIDNIGHT WITH
ISENTROPIC LIFT NOTED AT 300K AND HIGHER ALL SUGGESTIVE OF FAIRLY
DENSE CLOUD COVER LATE TONIGHT...ESPECIALLY OVER THE NORTHERN HALF
OF THE FORECAST AREA.
TEMPS...ENDED UP NEAR MAVMOS FOR LOWS OVERNIGHT AS COOLER THAN
EXPECTED TEMPS TODAY COUNTERACT POTENTIAL FOR TEMPS TO STAY UP WITH
CLOUDS TONIGHT. SHOULD END UP IN THE MID 20S MOST PLACES OVERNIGHT.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY/...
ISSUED AT 324 PM EST SAT NOV 24 2012
FORECAST CHALLENGES FOCUS ON PRECIP CHANCES AND TYPE WITH SURFACE
WAVE TRACKING THROUGH THE TENNESSEE VALLEY MONDAY NIGHT.
COLD FRONT WILL DROP SOUTH INTO THE REGION DURING THE DAY SUNDAY...
MAINTAINING MID AND HIGH LEVEL CLOUDS ACROSS THE NORTHERN HALF OF
THE FORECAST AREA. MODEL SOUNDINGS CONTINUE TO SHOW AN AXIS OF DEEP
MOISTURE ABOVE 10KFT AHEAD OF THE FRONT...GRADUALLY SHIFTING NORTH
BY LATE AFTERNOON AND EVENING AS MOISTURE PROFILES DECREASE AND
BOUNDARY LOSES ITS SURFACE CHARACTERISTICS AS IT SLIDES SOUTH.
WHATS LEFT OF THE BOUNDARY WILL SHIFT SOUTH OF THE OHIO RIVER ON
MONDAY AND BECOME NEARLY STATIONARY AS A SURFACE WAVE DEVELOPS OVER
TEXAS AND TRACKS NORTHEAST ALONG IT. MODEL CONSENSUS OVER THE LAST
COUPLE DAYS CONTINUE TO SHIFT THE TRACK OF THE LOW AND POSITION OF
THE BOUNDARY STEADILY SOUTH INTO THE TENNESSEE VALLEY BY LATE
MONDAY...LIKELY DUE AS MODELS CAPTURE THE STRENGTH OF THE
APPROACHING HIGH OVER THE NORTHERN PLAINS TO A GREATER DEGREE. THE
FURTHER SOUTH TRACK TO THIS SYSTEM IS PRESENTING SOME CHANGES NOT
ONLY IN THE AMOUNT OF PRECIPITATION BUT ALSO IN POTENTIAL PRECIP
TYPE AS COLDER AIR FILTERS INTO CENTRAL INDIANA MUCH QUICKER ON
MONDAY NIGHT.
HAVE LEANED TOWARDS THE CONSENSUS APPROACH BEING OFFERED BY THE
ECMWF/OP GFS/SREF WHICH BRING THE MOISTURE PLUME NORTH INTO THE OHIO
VALLEY LATE MONDAY AFTERNOON AHEAD OF THE UPPER LEVEL TROUGH AND
NORTH OF THE SURFACE WAVE...SPREADING EAST ACROSS THE REGION MONDAY
NIGHT. BEST ISENTROPIC LIFT NOW CONFINED TO MAINLY SOUTHERN PORTIONS
OF THE FORECAST AREA MONDAY NIGHT...AND EXPECT THE MOST WIDESPREAD
PRECIPITATION WILL SET UP FROM FAR SOUTHERN COUNTIES SOUTH INTO
KENTUCKY. FURTHER NORTH WHERE MOISTURE PROFILES ARE NOT AS
IMPRESSIVE...EXPECT LIGHTER PRECIP TO THE TUNE OF LESS THAN A TENTH
OF AN INCH. ANALYSIS OF MODEL SOUNDINGS AND LOW LEVEL THICKNESSES
SUGGESTIVE OF MAINLY LIGHT SNOW ALONG AND NORTH OF I-70 MONDAY
EVENING...WITH RAIN GRADUALLY MIXING WITH AND CHANGING OVER TO LIGHT
SNOW FURTHER SOUTH AS THE NIGHT WEARS ON. SOME HINTS OF A BAND OF
ENHANCED PRECIP SETTING UP NEAR OR JUST SOUTH OF THE FORECAST AREA
LATE MONDAY NIGHT AND SHOULD THE COLDER AIR ARRIVE FAST ENOUGH...
COULD SEE A QUICK BURST OF SNOW WITH A POSSIBLE ACCUM OF A FEW
TENTHS ACROSS FAR SOUTHERN COUNTIES BEFORE THE BETTER LIFT SHIFTS
EAST AROUND DAYBREAK TUESDAY. WITH THE CONSISTENT SHIFT SOUTH OF THE
TRACK OF THE SURFACE LOW THE LAST FEW DAYS...CONFIDENCE IS LOW ON
WHETHER THAT BAND OF ENHANCED PRECIP WILL SET UP OVER FAR SOUTHERN
COUNTIES OR IF ITS CLOSER TO THE OHIO RIVER. ANY LINGERING PRECIP
WILL END TUESDAY MORNING AS THE BROAD HIGH PRESSURE SHIFTS EAST INTO
THE REGION. COLD DRY WEATHER WILL THEN RESUME FOR CENTRAL INDIANA
FOR MIDWEEK.
TEMPS...LEANED TOWARDS COOLER MAVMOS FOR SUNDAY WITH POTENTIAL FOR
MORE CLOUDS ACROSS THE REGION. UNDERCUT MOS ON MONDAY WITH
INCREASING CLOUDS AND NORTHERLY FLOW AND AGAIN TUESDAY WITH COLD
ADVECTION IN WAKE OF THE STORM SYSTEM. NEAR MOS FOR LOWS TONIGHT...
THEN WENT ABOVE GUIDANCE FOR MONDAY NIGHT WITH MOS APPEARING TO
OVERDO THE COLD AIR INTRUSION.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
ISSUED AT 324 PM EST SAT NOV 24 2012
HIGH PRESSURE WILL BE IN CONTROL FOR THE MAJORITY OF THE EXTENDED
PERIOD RESULTING IN A COOL/DRY AIRMASS OVER CENTRAL INDIANA. TEMPS
WILL GRADUALLY WARM THROUGH THE COURSE OF THE PERIOD...AND
INITIALIZATION HAS A GOOD HANDLE ON IT...SO NO DEVIATIONS.
INITIALIZATION IS HINTING AT SOME PRECIP OVER THE NORTHERN PORTIONS
OF THE FORECAST AREA AT THE END OF THE PERIOD AS AN UPPER LEVEL
SHORTWAVE TRAVERSES CENTRAL INDIANA. THERE ARE A LOT OF
DISCREPANCIES IN THE MODELS AT THIS TIME THOUGH...SO WILL NOT MAKE
ANY CHANGES TO LATEST PRECIP INITIALIZATION. THE EURO AND GEM BARELY
HINT AT THE SHORTWAVE ON THURSDAY NIGHT/FRIDAY MORNING...WHILE
THE GFS SHOWS A SOMEWHAT DEVELOPED UPPER LEVEL LOW.
&&
.AVIATION /DISCUSSION FOR THE 24/2100Z TAF UPDATE/...
ISSUED AT 330 PM EST SAT NOV 24 2012
PERSISTENT STRATOCU DECK IS KEEPING CEILINGS AT MVFR CATEGORY AT THE
SITES AND SHOULD REMAIN THAT WAY THROUGH LATE AFTERNOON /23Z/ WHEN
THE CLOUDS SHOULD SCATTER OUT AND RETURN TO VFR CONDITIONS. AS LOW
LEVEL CLOUDS START TO SCATTER...HIGH CLOUDS WILL THEN START
FILTERING INTO TAF SITES THIS EVENING AHEAD OF AN APPROACHING COLD
FRONT. THIS WILL NOT IMPACT TAF SITES THOUGH...AND CONDITIONS WILL
REMAIN AT VFR CATEGORY FOR THE REMAINDER OF TAF PERIOD. WINDS WILL
BACK TO THE SOUTHWEST THIS EVENING AND BE SUSTAINED AT 3 TO 6 KTS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM....TDUD
AVIATION...TDUD/CP
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
324 PM EST SAT NOV 24 2012
.UPDATE...
THE SYNOPSIS...NEAR TERM...SHORT TERM AND LONG TERM SECTIONS HAVE
BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 324 PM EST SAT NOV 24 2012
DRY CONDITIONS WILL PERSIST INTO MONDAY AS HIGH PRESSURE PASSES TO
THE SOUTH OF THE REGION. A SURFACE LOW WILL TRACK ALONG A REMNANT
COLD FRONT THROUGH THE TENNESSEE VALLEY MONDAY NIGHT. MOISTURE
ASSOCIATED WITH THE LOW WILL LOFT INTO THE REGION...BRINGING CLOUDS
AND LIGHT RAIN CHANGING TO SNOW. COLD DRY WEATHER WILL RETURN FOR
MUCH OF THE REST OF THE WEEK AS BROAD HIGH PRESSURE BUILDS ACROSS
THE OHIO VALLEY.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 324 PM EST SAT NOV 24 2012
TEMPS HAVE BEEN HELD DOWN SO FAR TODAY AS EXTENSIVE STRATOCU DECK
REMAINS ACROSS MOST OF THE FORECAST AREA. AT 19Z...TEMPERATURES
RANGED FROM THE UPPER 20S TO LOWER 30S ACROSS THE REGION.
STRATOCU DECK IS THE INITIAL FOCUS OF THE FORECAST. VISIBLE
SATELLITE SHOWING EROSION OF THE STRATOCU ACROSS THE WABASH VALLEY
OVER THE LAST HOUR OR TWO AS LOW LEVEL FLOW BACKING IN RESPONSE TO
THE ARRIVAL OF THE RIDGE AXIS. EXPECT LOW CLOUDS TO GRADUALLY THIN
FROM THE WEST THROUGH THE REMAINDER OF THE AFTERNOON WITH SOME
SUNSHINE ANTICIPATED WEST OF I-65 PRIOR TO SUNSET. FURTHER
EAST...STRATOCU APPEARS MORE FIRMLY ENTRENCHED ON BACK SIDE OF DEEP
UPPER TROUGH. HAVE TRENDED TOWARDS RAP 900-925MB RH PROGS WHICH KEEP
CLOUDS INTO THE EVENING BEFORE THEY GIVE WAY FROM THE WEST.
ANY CLEARING HOWEVER IS LIKELY TO BE TEMPORARY ACROSS THE FORECAST
AREA AS MID AND HIGH LEVEL CLOUDS ARE ALREADY RAPIDLY EXPANDING EAST
ACROSS THE MID MISSISSIPPI VALLEY AND WILL ENCOMPASS THE REGION
OVERNIGHT. DEEP MOISTURE PRESENT ABOVE 600MB AFTER MIDNIGHT WITH
ISENTROPIC LIFT NOTED AT 300K AND HIGHER ALL SUGGESTIVE OF FAIRLY
DENSE CLOUD COVER LATE TONIGHT...ESPECIALLY OVER THE NORTHERN HALF
OF THE FORECAST AREA.
TEMPS...ENDED UP NEAR MAVMOS FOR LOWS OVERNIGHT AS COOLER THAN
EXPECTED TEMPS TODAY COUNTERACT POTENTIAL FOR TEMPS TO STAY UP WITH
CLOUDS TONIGHT. SHOULD END UP IN THE MID 20S MOST PLACES OVERNIGHT.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY/...
ISSUED AT 324 PM EST SAT NOV 24 2012
FORECAST CHALLENGES FOCUS ON PRECIP CHANCES AND TYPE WITH SURFACE
WAVE TRACKING THROUGH THE TENNESSEE VALLEY MONDAY NIGHT.
COLD FRONT WILL DROP SOUTH INTO THE REGION DURING THE DAY SUNDAY...
MAINTAINING MID AND HIGH LEVEL CLOUDS ACROSS THE NORTHERN HALF OF
THE FORECAST AREA. MODEL SOUNDINGS CONTINUE TO SHOW AN AXIS OF DEEP
MOISTURE ABOVE 10KFT AHEAD OF THE FRONT...GRADUALLY SHIFTING NORTH
BY LATE AFTERNOON AND EVENING AS MOISTURE PROFILES DECREASE AND
BOUNDARY LOSES ITS SURFACE CHARACTERISTICS AS IT SLIDES SOUTH.
WHATS LEFT OF THE BOUNDARY WILL SHIFT SOUTH OF THE OHIO RIVER ON
MONDAY AND BECOME NEARLY STATIONARY AS A SURFACE WAVE DEVELOPS OVER
TEXAS AND TRACKS NORTHEAST ALONG IT. MODEL CONSENSUS OVER THE LAST
COUPLE DAYS CONTINUE TO SHIFT THE TRACK OF THE LOW AND POSITION OF
THE BOUNDARY STEADILY SOUTH INTO THE TENNESSEE VALLEY BY LATE
MONDAY...LIKELY DUE AS MODELS CAPTURE THE STRENGTH OF THE
APPROACHING HIGH OVER THE NORTHERN PLAINS TO A GREATER DEGREE. THE
FURTHER SOUTH TRACK TO THIS SYSTEM IS PRESENTING SOME CHANGES NOT
ONLY IN THE AMOUNT OF PRECIPITATION BUT ALSO IN POTENTIAL PRECIP
TYPE AS COLDER AIR FILTERS INTO CENTRAL INDIANA MUCH QUICKER ON
MONDAY NIGHT.
HAVE LEANED TOWARDS THE CONSENSUS APPROACH BEING OFFERED BY THE
ECMWF/OP GFS/SREF WHICH BRING THE MOISTURE PLUME NORTH INTO THE OHIO
VALLEY LATE MONDAY AFTERNOON AHEAD OF THE UPPER LEVEL TROUGH AND
NORTH OF THE SURFACE WAVE...SPREADING EAST ACROSS THE REGION MONDAY
NIGHT. BEST ISENTROPIC LIFT NOW CONFINED TO MAINLY SOUTHERN PORTIONS
OF THE FORECAST AREA MONDAY NIGHT...AND EXPECT THE MOST WIDESPREAD
PRECIPITATION WILL SET UP FROM FAR SOUTHERN COUNTIES SOUTH INTO
KENTUCKY. FURTHER NORTH WHERE MOISTURE PROFILES ARE NOT AS
IMPRESSIVE...EXPECT LIGHTER PRECIP TO THE TUNE OF LESS THAN A TENTH
OF AN INCH. ANALYSIS OF MODEL SOUNDINGS AND LOW LEVEL THICKNESSES
SUGGESTIVE OF MAINLY LIGHT SNOW ALONG AND NORTH OF I-70 MONDAY
EVENING...WITH RAIN GRADUALLY MIXING WITH AND CHANGING OVER TO LIGHT
SNOW FURTHER SOUTH AS THE NIGHT WEARS ON. SOME HINTS OF A BAND OF
ENHANCED PRECIP SETTING UP NEAR OR JUST SOUTH OF THE FORECAST AREA
LATE MONDAY NIGHT AND SHOULD THE COLDER AIR ARRIVE FAST ENOUGH...
COULD SEE A QUICK BURST OF SNOW WITH A POSSIBLE ACCUM OF A FEW TENTHS
ACROSS FAR SOUTHERN COUNTIES BEFORE THE BETTER LIFT SHIFTS EAST
AROUND DAYBREAK TUESDAY. WITH THE CONSISTENT SHIFT SOUTH OF THE
TRACK OF THE SURFACE LOW THE LAST FEW DAYS...CONFIDENCE IS LOW ON
WHETHER THAT BAND OF ENHANCED PRECIP WILL SET UP OVER FAR SOUTHERN
COUNTIES OR IF ITS CLOSER TO THE OHIO RIVER. ANY LINGERING PRECIP
WILL END TUESDAY MORNING AS THE BROAD HIGH PRESSURE SHIFTS EAST INTO
THE REGION. COLD DRY WEATHER WILL THEN RESUME FOR CENTRAL INDIANA
FOR MIDWEEK.
TEMPS...LEANED TOWARDS COOLER MAVMOS FOR SUNDAY WITH POTENTIAL FOR
MORE CLOUDS ACROSS THE REGION. UNDERCUT MOS ON MONDAY WITH
INCREASING CLOUDS AND NORTHERLY FLOW AND AGAIN TUESDAY WITH COLD
ADVECTION IN WAKE OF THE STORM SYSTEM. NEAR MOS FOR LOWS TONIGHT...
THEN WENT ABOVE GUIDANCE FOR MONDAY NIGHT WITH MOS APPEARING TO
OVERDO THE COLD AIR INTRUSION.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
ISSUED AT 324 PM EST SAT NOV 24 2012
HIGH PRESSURE WILL BE IN CONTROL FOR THE MAJORITY OF THE EXTENDED
PERIOD RESULTING IN A COOL/DRY AIRMASS OVER CENTRAL INDIANA. TEMPS
WILL GRADUALLY WARM THROUGH THE COURSE OF THE PERIOD...AND
INITIALIZATION HAS A GOOD HANDLE ON IT...SO NO DEVIATIONS.
INITIALIZATION IS HINTING AT SOME PRECIP OVER THE NORTHERN PORTIONS
OF THE FORECAST AREA AT THE END OF THE PERIOD AS AN UPPER LEVEL
SHORTWAVE TRAVERSES CENTRAL INDIANA. THERE ARE A LOT OF
DISCREPANCIES IN THE MODELS AT THIS TIME THOUGH...SO WILL NOT MAKE
ANY CHANGES TO LATEST PRECIP INITIALIZATION. THE EURO AND GEM BARELY
HINT AT THE SHORTWAVE ON THURSDAY NIGHT/FRIDAY MORNING...WHILE
THE GFS SHOWS A SOMEWHAT DEVELOPED UPPER LEVEL LOW.
&&
.AVIATION /DISCUSSION FOR THE 24/1800Z TAF ISSUANCE/...
ISSUED AT 1230 PM EST SAT NOV 24 2012
PERSISTENT STRATOCU DECK IS KEEPING CEILINGS AT MVFR CATEGORY AT
KBMG AND KHUF AND SHOULD REMAIN THAT WAY THROUGH LATE AFTERNOON.
AFTER THAT...KBMG AND KHUF WILL RETURN TO VFR CONDITIONS.
MEANWHILE...KIND AND KLAF HAVE ALREADY REACHED VFR CATEGORY BUT
REMAIN OVERCAST. AS LOW LEVEL CLOUDS START TO SCATTER...HIGH
CLOUDS WILL THEN START FILTERING INTO TAF SITES THIS EVENING AHEAD
OF AN APPROACHING COLD FRONT. THIS WILL NOT IMPACT TAF SITES
THOUGH...AND CONDITIONS WILL REMAIN AT VFR CATEGORY FOR THE
REMAINDER OF TAF PERIOD. WINDS WILL BACK TO THE SOUTHWEST THIS
EVENING AND BE SUSTAINED AT 3 TO 6 KTS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM....TDUD
AVIATION...TDUD
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
1221 PM EST SAT NOV 24 2012
.AVIATION...
CEILINGS WILL GRADUALLY IMPROVE THROUGH THE AFTERNOON AS DRIER AIR
WORKS INTO THE REGION AND LOW LEVEL WINDS BACK TO A MORE
SOUTHWESTERLY DIRECTION. THIS WILL TAKE SOME TIME THOUGH WITH
PERSISTENT CYCLONIC FLOW OVER THE AREA. STRATOCU DECK WILL SCATTER
COMPLETELY BY LATE THIS EVENING WITH VFR CONDITIONS CONTINUING
THROUGH THE REST OF THE PERIOD. A PASSING SHORTWAVE TROUGH WILL
BRING AN INCREASE IN MIDLEVEL CLOUDS ASSOCIATED WITH WAA ALOFT BUT
CEILINGS WILL STAY WELL ABOVE 5 KFT.
&&
.PREV DISCUSSION... /ISSUED 1032 AM EST SAT NOV 24 2012/
UPDATE...
LATEST RADAR AND SURFACE OBSERVATIONS SHOW LITTLE MORE THAN
FLURRIES ACROSS THE AREA THIS MORNING THANKS TO IMPRESSIVE DRY AIR
ENTRAINMENT. CEILINGS ARE HOVERING AROUND 2500 FT WITH VERY DRY
AIR ABOVE 5-6 KFT...SEVERELY LIMITING SNOW POTENTIAL. UPDATED
FORECAST TO REMOVE ALL POPS AND TO EXPAND FLURRIES IN THE
NORTHEAST. THIS RELATIVELY THIN LAYER OF STRATOCU HAS BEEN SLOW
TO ERODE TO OUR SOUTHWEST THOUGH AND MADE SOME ADJUSTMENTS TO SKY
COVER AS WELL. EXPECT CLOUDS AND FLURRIES WILL CONTINUE UNTIL LATE
THIS AFTERNOON WHEN THE FLOW BECOMES INCREASINGLY ANTICYCLONIC
WITH BUILDING MIDLEVEL HEIGHTS AND LARGE SCALE SUBSIDENCE. ALSO
SHAVED A DEGREE OR TWO OFF HIGH TEMPS OWING TO MORE PESSIMISTIC
CLOUD FORECAST.
PREV DISCUSSION... /ISSUED 341 AM EST SAT NOV 24 2012/
SHORT TERM...
FAILED LES RESPONSE ALG WRN PERIPHERY OF LK MI SO FAR OWING TO
DEGREE OF DRY ENTRAINMENT ONGOING OUT OF WI. MOST FVRBL LK SP FETCH
PRECONDITIONING 2 INTENSE BANDS ACRS NRN LWR STRETCHING SEWD INTO
THE THUMB. SOME INDICATION IN RECENT RADAR IMAGERY OF WK BANDING
DVLPG ALG A KMKG-KBIV LINE AND IF THAT INDEED DVLPS AS RUC SOLUTIONS
SUGGEST THAT CONTD SHALLOW BNDRY LYR VEERING SHLD ALLOW THAT TO SAG
SWD THROUGH MID MORNING. HWVR GIVEN THE DEARTH OF ADDNL MSTR ALOFT
WILL BACK POPS OFF CONSIDERABLY.
OTHERWISE CONTD QUITE COLD TDA W/LG AREA OF STRATO CU LOCKED IN
BENEATH FAIRLY SHARP LL INVERSION. FLW BACKS LT AFTN WHICH WILL
ERODE SWRN EDGE AND PROMOTE LIMITED INSOLATION BUT CONSIDERED TOO
LATE TO APPRECIABLE PROMOTE MORE OF A DIURNAL RESPONSE. GREATER CLRG
XPCD GOING INTO THIS EVENING AHD OF INCOMING HIGH CLD SHIELD
ASSOCD/W FAST MOVING DISTURBANCE OVR SWRN CANADA. LOSS OF DEEPER SC
UNDERNEATH ENVELOPING BUT THIN HIGH CLD SHIELD PERPLEXING GIVEN COLD
MOS GUIDANCE IN LIGHT OF SWRLY RTN FLW DVLPG ON BACKSIDE OF
DEPARTING RIDGE AXIS. THUS WILL ONLY MAKE SLIGHT ADJUSTMENTS FOR
TYPICAL LOCAL COLD SPOTS.
UPSTREAM SYS WILL DEAMPLIFY QUICKLY SEWD ON SUN. WAA AHD OF THIS FTR
AND PARTIAL SUN WILL YIELD A BTR DIURNAL RESPONSE W/ANTICIPATED
GREATER MIXING AND GAVE A +1 BUMP HIGHER.
LONG TERM...MONDAY THROUGH FRIDAY
MAIN FOCUS REMAINS ON DWINDLING CHANCES FOR SNOW WITH SYSTEM NOW
PROGGED TO TRACK THROUGH THE TN/OH VALLEYS LATE MONDAY AFTERNOON
THROUGH TUESDAY MORNING. 12/00Z GFS/GEFS/GEM ITERATIONS HAVE ALL
TRENDED TOWARD THE LESS AMPLIFIED AND THEREFORE FARTHER SOUTH
SOLUTION OF THE ECMWF WITH A SFC LOW TRACK FROM THE SOUTHERN PLAINS
EAST THROUGH THE TN VALLEY. THIS SOUTHERLY TRACK WOULD RESULT IN
DRY/COLD CONDITIONS LOCALLY WITH SFC HIGH PRESSURE BUILDING INTO THE
SOUTHERN GREAT LAKES. HOWEVER...WOULD NOT BE SURPRISED TO SEE MODELS
TREND BACK A LITTLE TO THE NORTH AND MORE AMPLIFIED WITH THIS
POSITIVE PV ANOMALY AS IT DROPS SOUTHEAST INTO THE MIDWEST. INITIAL
PROGRESSIVE POSITIVE TILT AND CONFLUENCE ACROSS THE LAKES WILL KEEP
IT FROM MAKING IT TOO FAR NORTH BUT CANNOT RULE OUT NORTHERN FRINGE
OF PCPN SHIELD CLIPPING OUR AREA. GUIDANCE OFTEN WEAKENS OR LOSES A
STORM IN THE 4-5 DAY PERIOD ONLY TO LATCH BACK ONTO A STRONGER
SOLUTION WITHIN 72 HOURS AS WAVE FINALLY REACHES OUR RADIOSONDE
NETWORK. HAVE BEEN BURNT BY THIS SEVERAL TIMES SO OPTED TO RETAIN
LOWER CHANCE POPS MAINLY MONDAY NIGHT...HIGHEST SOUTH. THIS WILL
NEED TO BE MONITORED CLOSELY GIVEN PROSPECTS FOR A NARROW SWATH OF
ACCUMULATING SNOW ON THE NORTHERN FLANK OF THIS SYSTEM.
ATTENTION FOR THE MID TO LATE WEEK PERIOD WILL TURN TO TEMPERATURES
AND CLOUD COVER. TOUGH FORECAST AS AREA LIKELY TO BE NEAR A FRONTAL
BOUNDARY ON THE SOUTHWESTERN FRINGE OF A RETREATING POLAR
JET...ESPECIALLY BY THURSDAY AND FRIDAY. A DEVELOPING NEGATIVE
NAO/AO WILL HELP MAINTAIN NORTH ATLANTIC/EASTERN CANADA
BLOCKING...WHILE -PNA AND NORTHEAST PACIFIC NEGATIVE HEIGHT ANOMALY
ALLOW RIDGING/WARMTH TO OVERSPREAD THE PLAINS/MIDWEST. WE`LL BE IN
BETWEEN MAKING IT A DIFFICULT FORECAST. GIVEN THE UNCERTAINTIES
OPTED TO LOAD AND GO WITH THE 00Z ALLBLEND WHICH DOESN`T LOOK TOO
BAD AT THIS POINT WITH TEMPS TRENDING UP TO NEAR NORMAL BY
THURSDAY/FRIDAY. CLOUDS WITH ANY MOISTURE STARVED (LOW AMPLITUDE)
SHORTWAVES IN WNW FLOW WILL ALSO IMPACT TEMPS...ESPECIALLY LATE
THURSDAY INTO FRIDAY PER A ECMWF/GFS/GEFS COMPROMISE. GUIDANCE ALSO
PRINTING OUT SOME LIGHT QPF WITH THIS WAVE BUT WILL HOLD OFF ADDING
ANY POPS GIVEN TIMING DIFFERENCES AND LACK OF MOISTURE/FORCING WITH
SHEARED WAVE(S).
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS EVENING FOR LMZ043-046.
&&
$$
SHORT TERM...T
LONG TERM...STEINWEDEL
AVIATION...AGD
UPDATE...AGD
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
548 PM EST SAT NOV 24 2012
.SYNOPSIS...
SNOW CURRENTLY AFFECTING A LARGE PORTION OF THE FORECAST AREA WILL
DIMINISH TONIGHT. TEMPERATURES WILL REMAIN BELOW NORMAL THROUGH THE
WEEK...WITH THE NEXT CHANCE FOR SNOW COMING MONDAY NIGHT INTO
TUESDAY.
&&
.NEAR TERM /THROUGH SUNDAY/...
INVERSION HEIGHTS PER THE NAM AND RAP ARE ALREADY FALLING OFF THIS
EVENING DOWNWIND OF LAKE ERIE. THEY STARTED OUT ABOVE 8 KFT
EARLIER...AND SHOULD FALL TOWARD 5 KFT WITHIN THE NEXT FEW HOURS.
WHILE INSTABILITY IS STILL RATHER IMPRESSIVE GIVEN LAKE
TEMPERATURES AROUND +7 TO +8C AND MODEL 850 MB TEMPERATURES AROUND
-11C...THE LENGTH OF FETCH OVER THE LAKE AS WELL AS UPSTREAM
ANTECEDENT CONDITIONS REALLY ARE NOT. BOUNDARY LAYER DEWPOINTS
NORTH OF LAKE HURON ARE RUNNING NEAR 10F...WHILE IS YIELDING
DEWPOINT DEPRESSIONS OF 10-20F IN SOUTHERN ONTARIO. THIS IS JUST A
BIT TOO DRY TO GET LAKE EFFECT HUMMING ALONG WITHOUT MULTI-LAKE
FLOW CONDITIONS. AS IT STANDS...WE NEVER FULLY GOT A MULTI-LAKE
CONNECTION BETWEEN LAKE HURON AND LAKE ERIE TO GET THE BANDING
GOING OVER OUR AREA AS THE LOW LEVEL FLOW COMPONENT WAS A BIT TOO
WESTERLY. AS A RESULT...WHILE WIDESPREAD SNOW SHOWERS DID STILL
OCCUR...THE BANDING THAT FLOWED OVER MORE THAN ONE LAKE REMAINED
MAINLY IN NORTHERN LOWER MICHIGAN (SUPERIOR/MICHIGAN) AND UPSTATE
NEW YORK (HURON/ERIE). AS LOW LEVEL FLOW BACKS AGAIN TONIGHT IN
RESPONSE TO ANOTHER SHORT WAVE DIVING SOUTHWARD...THIS SHOULD EVEN
BRING THE SNOW SHOWERS AND FLURRIES WE HAVE AROUND THIS EVENING TO
AN END.
BECAUSE OF THE AFOREMENTIONED PROBLEMS FOR MODERATE SNOWFALL
ACCUMULATIONS...THE LAKE EFFECT SNOW ADVISORY HAS BEEN DROPPED.
ANY ENHANCED BANDS THAT MAY PERK UP THIS EVENING WILL BE HANDLED
WITH SPECIAL WEATHER STATEMENTS...HOWEVER THE LIKELIHOOD OF
STRONGER BANDS IS DECREASING BY THE HOUR ACROSS THE AREA. FRIES
PREVIOUS DISCUSSION ABOUT TOMORROW FOLLOWS...
A SHORTWAVE IS EXPECTED TO SPEED TO THE EAST TOMORROW...RACING
FROM LOWER MICHIGAN IN THE MORNING TO NEW JERSEY IN THE EVENING.
OVER THE LAST FEW DAYS...MODELS HAVE VERY GRADUALLY INTENSIFIED
THE SHORTWAVE IN ADDITION TO BRINGING IT FARTHER TO THE SOUTH.
APPEARS THAT ANY PRECIPITATION ASSOCIATED WITH THE SHORTWAVE WILL
JUST GLANCE THE LOCAL FORECAST AREA...AND ALTHOUGH POPS COME A BIT
FARTHER SOUTH THAN PREVIOUS FORECAST...HAVE NOT GONE MUCH FARTHER
SOUTH THAN INTERSTATE 80. EXPECT SOME MINOR IMPROVEMENT IN HIGH
TEMPERATURES COMPARED TO TODAY WITH SOUTHWESTERLY WINDS AT 10-15
MPH...BUT TEMPERATURES WILL STILL BE SEVERAL DEGREES BELOW NORMAL.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
WEAK HIGH PRESSURE WILL MOVE INTO THE SOUTHEASTERN UNITED
STATES...ALLOWING FOR AT LEAST ONE DAY OF DRY WEATHER FOR ALL
COUNTIES SUNDAY NIGHT INTO MONDAY. MODELS THEN FOLLOW THE HIGH
PRESSURE WITH A CYCLONE...WITH MUCH OF THE PRECIPITATION FALLING
TO THE NORTH OF THE SURFACE LOW. MODELS HAVE BEEN QUITE
INCONSISTENT WITH THE STORM DURING THE LAST COUPLE OF DAYS...AND
THEREFORE HAVE DECIDED NOT TO MAKE ANY MAJOR CHANGES TO THIS
PORTION OF THE FORECAST. MADE SOME SLIGHT TWEAKS WITH TIMING OF
SYSTEM...BUT OTHERWISE WILL KEEP GENERAL FORECAST OF CHANCE
POPS...WITH SOME LIKELY POPS CREEPING INTO THE RIDGES. ANY
PRECIPITATION IS EXPECTED TO START AS SNOW MONDAY NIGHT...WITH
MOST PLACES CHANGING OVER TO RAIN ON TUESDAY. TEMPERATURES WILL
REMAIN BELOW NORMAL.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
A CHANCE OF A RAIN SNOW MIX OVER MOST OF THE REGION TUESDAY NIGHT
INTO WEDNESDAY AS SURFACE LOW MOVES TOWARD THE UPPER OHIO VALLEY.
THIS SYSTEM THEN MOVES EASTWARD BY WEDNESDAY WITH ANOTHER SHOT OF
NORTHWEST FLOW AGAIN BRINGING THE CHANCE FOR A SHORT PERIOD OF
LAKE EFFECT SNOW FLURRIES AND SHOWERS. THEN BY WEDNESDAY NIGHT DRY
AND CONTINUED SEASONABLE THROUGH SATURDAY.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
MVFR CONDS EXPECTED THRU EARLY TONIGHT...WITH LAKE EFFECT SNOW
SHOWERS OCCURRING AT MOST TERMINALS EXCEPT ZZV. IMPROVEMENT TO VFR
CONDITIONS OVERNIGHT. WINDS WILL TURN MORE WEST AS SURFACE RIDGE
SHIFTS EAST OVERNIGHT.
.OUTLOOK.../SUNDAY THROUGH THURSDAY/...
A CLIPPER MOVING THROUGH THE REGION AHEAD OF NEXT SYSTEM WILL
BRING CLOUDS FROM OVERRUNNING SUNDAY. CHANCE FOR MVFR/IFR WITH
RAIN/SNOW LATE MONDAY INTO TUESDAY...LINGERING IN THE NORTHERN
AREAS WEDNESDAY. CONDITIONS SHOULD DRY OUT BY THURSDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
353 PM EST SAT NOV 24 2012
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 350 PM EST SAT NOV 24 2012
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW NW FLOW ALF OVER
THE GRT LKS BTWN TROF OVER ERN NAMERICA AND A RDG OVER THE ROCKIES.
RIGHT NOW...THERE IS A SHRTWV RDG ALF DOMINATING THE UPR LKS...WITH
SFC HI PRES RDG AXIS STRETCHING FM NOW ONTARIO S INTO THE UPPER
MIDWEST. DESPITE THE APRCH OF THIS RDG AXIS AND LO INVRN BASE SHOWN
ON THE 12Z INL/MPX RAOBS THAT HAS ALLOWED AT LEAST PARTIAL CLEARING
OF LO CLDS OVER MN...THE SC OVER THE CWA HAS BEEN QUITE RESILIENT
WITH H925-85 THERMAL TROF /H85 TEMPS IN THE -12C TO -15C RANGE/
UNDER HIER INVRNS H85-5 AS SHOWN ON THE 12Z GRB/APX RAOBS IN THE
LLVL NW FLOW E OF THE INCOMING SFC HI PRES RDG. THESE LO CLDS ARE
TENDING TO BREAK UP MORE AGGRESSIVELY OVER THE FAR SCENTRAL CWA WITH
DOWNSLOPE NATURE OF THE LLVL FLOW. ALTHOUGH LOWERING SUBSIDENCE
INVRN HAS TENDED TO CAUSE THE LES IN THE CHILLY NW FLOW TO DIMINISH
WITH TIME...THE SHSN HAVE BEEN MOST PERSISTENT NEAR MUNISING WITH
UPSTREAM MOISTENING OFF LK NIPIGON AND MORE LLVL CNVGC ENHANCING THE
LES IN THAT AREA. LOOKING TO THE W...SKIES ARE PCLDY CLOSE TO THE
SFC RDG AXIS...BUT THICKER CLDS ASSOCIATED WITH WAD IN THE SSW FLOW
AHEAD OF ANOTHER SHRTWV NEAR LK WINNIPEG THAT HAS BEEN RIDING OVER
THE ROCKIES RDG ARE MOVING STEADILY TO THE E INTO ERN MN THIS AFTN.
SOME -SN HAS MOVED INTO NW MN THIS AFTN UNDER DEEP ISENTROPIC
ASCENT/SOME UPR DVGC IN THE EXIT REGION OF 120KT H3 JET MAX
SUPPORTING THE SHRTWV.
MAIN FCST CONCERNS THRU SUN INCLUDE TIMING OF SN AND PCPN AMOUNTS
TNGT IN ADVANCE OF CLIPPER TYPE SHRTWV NEAR LK WINNIPEG AND THEN
TRANSITION TO LES ON SUN IN ITS WAKE.
TNGT...AS SFC HI PRES RDG SHIFTS TO THE ERN GRT LKS...EXPECT SW
FLOW/ISENTROPIC ASCENT BTWN DEPARTING RDG AND SHRTWV NEAR LK
WINNIPEG TRACKING TO THE ESE ACRS ONTARIO TO DOMINATE. SINCE THE
MAIN PV ANOMALY WL BE PASSING TO THE N...SHARPER ISENTROPIC ASCENT
BEST SHOWN ON THE 280-290K SFCS /H8-65/ WL BE TRANSIENT AS WARM
CONVEYOR BELT MSTR AXIS SWINGS THRU THE UPR LKS AHEAD OF DRY
SLOTTING ON THE SRN FLANK OF PV ANOMALY TRACK. -SN SHOULD ARRIVE
OVER THE W IN THE EVNG AND PUSH TO ERY AFTER 06Z...WHEN THE PCPN WL
BEGIN TO DIMINISH W-E FOLLOWING THE SHIFT OF THE WARM CONVEYOR BELT
RIBBON TO THE E. PCPN CHCS WL BE ENHANCED BY RIBBON OF H85-7 FGEN...
SOME UPR DVGC IN LEFT EXIT REGION OF H3 JET MAX SUPPORTING THE
ONTARIO SHRTWV...AND SOME DPVA ASSOCIATED WITH ANOTHER SHRTWV
TRACKING THRU THE UPR MIDWEST ON THE SRN FLANK OF THE MAIN PV
ANOMALY. GIVEN FCST H7 SPECIFIC HUMIDITY UP TO 2 G/KG AND A 3-6 HR
PERIOD OF -SN WITH TRANSIENT WARM CONVEYOR BELT/DEEP ASCENT...LOOKS
LIKE 1 TO 2 INCHES OF SN IS LIKELY WITH DECENT OMEGA IN THE DGZ. 12Z
GUIDANCE SHOWS THE SHARPER ISENTROPIC ASCENT/FGEN IMPACTING THE WI
BORDER AREA WITH HIER QPF/SN AMOUNTS ARND 2 INCHES MOST LIKELY
THERE. SOME OF THE MODELS ALSO HINT THERE COULD BE SOME LK
ENHANCEMENT OFF LK MI...BUT THE H925 WINDS LOOK TO BACK TO A MORE
FAVORABLE SW DIRECTION ONLY BRIEFLY TO ALLOW FOR TOO MUCH
ENHANCEMENT AT ISQ-ERY. WITH RELATIVELY QUICK ARRIVAL OF THICKER
CLDS/WAD THIS EVNG...EXPECT NEAR STEADY TEMPS MUCH OF THE NGT AFTER
EARLY MODEST DIURNAL TEMP FALL.
SUN...LINGERING -SN OVER THE E WL END SOON AFTER 12Z FOLLOWING EXIT
OF WARM CONVEYOR BELT MSTR RIBBON TO THE E AND ARRIVAL OF DRY
SLOTTING. HOWEVER...12Z MODELS HAVE TENDED TO DIG THE PV ANOMALY
MORE TO THE ESE OVER NE LK SUP DURING THE DAY. SO AS THE DAY GOES
ON...A COLD CYC NW FLOW WL DVLP IN THE WAKE OF COLD FROPA AS
ASSOCIATED SFC LO SHIFTS TO JUST E OF LK SUP BY 00Z MON. AT THE SAME
TIME...AN AXIS OF SHARPER QVECTOR CNVGC/DPVA AND SOME DEEPER MSTR WL
IMPACT MAINLY THE NE HALF OF THE FA CLOSER TO THE TRACK OF THE
SHRTWV. WITH H85 TEMPS PROGGED TO FALL AS LO AS -15C OVER THE W HALF
OF LK SUP IN THE AFTN...EXPECT MORE WDSPRD LES TO DEVELOP IN THAT
AREA. ALSO BUMPED UP POPS OVER THE NE IN THE AFTN ESPECIALLY NEAR LK
SUP GIVEN FAVORABLE ALIGNMENT OF ONSHORE WNW FLOW...DEEPER MSTR/
DPVA/QVECTOR CNVGC...AND COOLING. THE DAY SHOULD BE DRY OVER THE
SCENTRAL WITH DOWNSLOPE FLOW IN THE ABSENCE OF ANY DYNAMIC
SUPPORT/DEEP MSTR THERE.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 350 PM EST SAT NOV 24 2012
THE MAIN FOCUS IN THE LONG TERM REVOLVES AROUND THE CHANCE FOR
MODERATE LAKE EFFECT SNOW ACCUMULATION EAST NEAR LAKE SUPERIOR
LATE SUNDAY NIGHT THROUGH MONDAY. EXACT LOCATIONS OF THIS POTENTIAL
ARE STILL UNCERTAIN...THOUGH THE MAIN THREAT APPEARS TO BE IN ALGER
COUNTY FROM MUNISING TO GRAND MARAIS AND SOUTH INTO NORTHERN
SCHOOLCRAFT COUNTY. ANOTHER ROUND OF LIGHT SNOW VERY SIMILAR TO
TONIGHTS SYSTEM WILL MOVE THROUGH THE AREA TUESDAY NIGHT. MILDER
PATTERN CHANGES WILL THEN BE IN THE MAKING TOWARD THE END OF THE
WEEK.
SUNDAY NIGHT THROUGH MONDAY NIGHT...THE SHORTWAVE TROUGH ASSOCIATED
WITH THE CLIPPER SYSTEM NOTED IN THE SHORT TERM WILL BE CROSSING
NORTH-CENTRAL LAKE SUPERIOR AND WESTERN UPPER MI AT THE START OF THE
PERIOD. THE ECMWF AND REGIONAL GEM HAVE BEEN QUICKER WITH THE
SHORTWAVE WITH EACH PROGRESSIVE RUN...AND HAVE COME IN LINE WITH THE
GFS AND NAM SOLUTIONS. TRENDS FROM BOTH THE GFS AND ECMWF ARE TO ADD
SUBTLE AMPLIFICATION TO THE WNW FLOW IN THE MID-LEVELS OVER THE
GREAT LAKES...WHILE THE REGIONAL GEM HAS TRENDED TO A LESS AMPLIFIED
FLOW. PREFER THE IDEA PRESENTED BY THE GFS/ECMWF AS THE NICE SHOT OF
CAA BEHIND THE LOW-LEVEL CLIPPER WILL LIKELY ADD SOME AMPLIFICATION
TO THE MID-LEVEL TROUGHING.
LINGERING LIGHT SNOW FROM THE CLIPPER WILL BE ENDING ACROSS THE
EASTERN PORTION OF THE CWA AT 00Z MONDAY AS THE LOW DEPARTS INTO SE
ONTARIO. CAA IMMEDIATELY BEHIND THE SYSTEM IS NOT ALL THAT
IMPRESSIVE...WITH H8 TEMPS ONLY AROUND -10C OVER EASTERN LAKE
SUPERIOR AT 06Z MONDAY. HOWEVER...H8 TEMPS BEGIN TO FALL FOR THE
WESTERN HALF...REACHING -14C BY 06Z MONDAY. AT THE SAME TIME...A
WEAK RIDGE BETWEEN THE DEPARTING TROUGH AND INCOMING AMPLIFYING
TROUGH WILL BE PASSING OVERHEAD AND LIKELY DISRUPT THE LOW-LEVEL
SURFACE FLOW. WHAT MAKES THIS CONCERNING IS THAT SFC TO H8 FLOW FROM
THE NW WOULD PUT A DOMINANT LES BAND INTO FAR EASTERN ALGER COUNTY
BEGINNING SUNDAY EVENING...WHILE A BACKING OF THE FLOW BEHIND THE
SUBTLE RIDGE WOULD TEMPORARILY PUSH THE BAND ALONG THE SHORE. STILL
BEING TWO DAYS OUT...THE CONNECTION BETWEEN THE MID-LEVEL FLOW AND
SFC LES SET-UP IS SOMEWHAT UNCLEAR...BUT WOULD NOT BE SURPRISED IF
THE BAND WOBBLES BETWEEN EASTERN ALGER COUNTY AND NORTHERN LUCE
COUNTY ON EARLY MONDAY MORNING. THEN...THE SECONDARY TROUGH WILL AID
LES INTENSITY ACROSS THE WHOLE NORTH SHORE OF UPPER MI LATER MONDAY
MORNING INTO THE AFTERNOON. THIS WILL OCCUR AS THE BEST CAA AND
COLDEST H8 TEMPS...AROUND -15 TO -16C...WILL BE MOVING OVER THE
LAKE. ADDITIONALLY...LAKE-INDUCED EQUILIBRIUM VALUES BASED OFF OF A
CONSERVATIVE LAKE WATER TEMPERATURE OF 5C WILL BE UPWARDS OF 7KFT
ACROSS THE WEST AND 9KFT FOR THE EAST. FINALLY...THE DGZ WILL BE
LOCATED IN THE HIGHEST 3KFT OF THE CONVECTIVE LAYER IN THE
EAST...LEADING TO THE POTENTIAL FOR INCREASED AGGREGATION FROM
DENDRITES AND THUS HIGHER SNOW RATIOS OF ABOUT 20 TO 1.
THEREFORE...EXPECT THE HIGHEST LES INTENSITY MONDAY MORNING INTO
EARLY AFTERNOON OVER THE EAST NEAR LAKE SUPERIOR.
THE NAM...GEM...AND LOCAL WRF ALL HAVE A DOMINANT BAND WITH
SIGNIFICANT LES FOR CENTRAL ALGER AND NORTHERN SCHOOLCRAFT COUNTY. A
BLEND OF NAM AND LOCAL WRF QPF RESULTED IN ACCUMULATIONS OF 6-10
INCHES CENTERED OVER MELSTRAND. ONLY USED THIS BLEND TO SEE
POTENTIAL AND WILL USE A MORE CONSERVATIVE APPROACH GIVEN THE
UNCERTAINTY OF BAND PLACEMENT. NEEDLESS TO SAY...HEADLINES MAY BE
NEEDED IF HI-RES MODELS REMAIN CONSISTENT WITH LES BAND PLACEMENT.
DRY AIR ADVECTION FROM THE SOUTHWEST IN THE LOW LEVELS...AND H8 WAA
OVERNIGHT MONDAY WILL BEGIN TO ERODE LES FROM WEST TO EAST ACROSS
THE CWA. INVERSION HEIGHTS WILL ALSO CRASH FROM AROUND 9KFT 00Z
TUESDAY TO <5KFT BY 09Z TUESDAY. MEANWHILE WINDS WILL BEGIN BACKING
AND SHOULD PUSH REMAINING LES OFFSHORE...WITH LITTLE ACTIVITY
REMAINING BY TUESDAY MORNING.
TUESDAY THROUGH WEDNESDAY...ANOTHER SHORTWAVE TROUGH DIGGING ESE OUT
OF CANADA WILL IMPACT THE CWA BY TUESDAY AFTERNOON AND BRING A ROUND
OF LIGHT SNOW TO MAINLY THE NORTHERN CWA. THE BEST UPPER LEVEL PV
ANOMALY AND MID-LEVEL Q-VECTOR DIVERGENCE ARE PROGGED TO MOVE
THROUGH TUESDAY AFTERNOON AND EVENING. THE LEFT EXIT OF A 120KT NW
TO SE ORIENTED UPPER JET WILL BE TRACKING ACROSS CENTRAL WI...SO
BEST FEATURES DO NOT QUITE LINE UP. THE LOWEST LEVELS WILL BE DRY
ENOUGH TO THE SOUTH TO PREVENT INITIAL PRECIP FROM REACHING THE
GROUND. DID NOT MAKE MANY CHANGES TO THE PREVIOUS FORECAST OTHER
THAN INCREASE POPS SLIGHTLY FOR THE ENTIRE CWA. THE TROUGH AXIS WILL
THEN PASS THROUGH THE CWA BY 12Z WEDNESDAY AND USHER IN
ANOTHER...YET SHORT-LIVED AND WEAKER...LES EVENT. INVERSION HEIGHTS
COLLAPSE QUITE QUICKLY TO ABOUT 4KFT BY WEDNESDAY AFTERNOON...AND
THE AIR BEHIND THIS SYSTEM IS CONSIDERABLY DRY THROUGHOUT THE
COLUMN. THEREFORE...EXPECTATION IS THAT THERE WILL BE A QUICK LES
EVENT WEDNESDAY MORNING INTO EARLY AFTERNOON FOR THE NW
SNOWBELTS...MAINLY ACROSS THE KEWEENAW PENINSULA AND EAST OF
MUNISING WHERE MOISTURE IS MORE ABUNDANT.
WEDNESDAY NIGHT THROUGH SATURDAY...THE PATTERN TURNS QUIET FOR MUCH
OF THE UPPER GREAT LAKES FOR THE SECOND HALF OF THE WEEK. OTHER THAN
SOME LIGHT LES POSSIBLE EAST NEAR LAKE SUPERIOR ON THURSDAY
NIGHT...NO REAL SIGNIFICANT PRECIP CHANCES PRESENT THEMSELVES AS THE
MAIN ENERGY REMAINS SOUTH OF THE CWA WITH AN UPPER LEVEL DISTURBANCE
MOVING ACROSS THE MID MISSISSIPPI VALLEY ON FRIDAY. THOUGH ON THE
EDGE OF THE FORECAST PERIOD...A STRONG RIDGE WITHIN PACIFIC FLOW
LOOKS TO BRING WELL-ABOVE AVERAGE TEMPS TO BEGIN DECEMBER.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 350 PM EST SAT NOV 24 2012
EXPECT MVFR CIGS AT ALL 3 SITES TO GIVE WAY TO VFR CONDITIONS BY
THIS EVNG WITH THE ARRIVAL OF A SFC HI PRES RDG AXIS. SOME -SN IN
ADVANCE OF THE NEXT CLIPPER TYPE LO PRES SYSTEM WL THEN ARRIVE W-E
LATER THIS EVNG...LIKELY DROPPING VSBYS TO IFR RANGE DURING THE
EXPECTED 3-6HR PERIOD OF -SN. AFTER THE -SN ENDS W-E...EXPECT
LINGERING MVFR CIGS WITH RESIDUAL LLVL MSTR. THE ARRIVAL OF COLDER
AIR WL GENERATE MORE LK EFFECT -SHSN ON SUN MRNG...ESPECIALLY AT IWD
AND ESPECIALLY CMX WHERE THE FCST W WIND WL UPSLOPE. ON THE OTHER
HAND...CONDITIONS ARE LIKELY TO TREND TO VFR ON SUN AT SAW WITH
DOWNSLOPE WIND COMPONENT.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 350 PM EST SAT NOV 24 2012
EXPECT S-SW WINDS UP TO 20 KTS IN ADVANCE OF A CLIPPER SYSTEM
TONIGHT TO VEER TO THE WNW ON SUN AS THE LO MOVES TO THE E OF LAKE
SUP AND DRAGS A COLD FRONT ACROSS THE AREA.
NORTHWEST WINDS OF 20 TO 30 KNOTS DUE TO HIGH PRESSURE QUICKLY
IMPINGING ON A DEPARTING LOW OVER FAR EASTERN UPPER MICHIGAN WILL BE
POSSIBLE SUNDAY NIGHT...WITH EVEN A FEW GALE FORCE GUSTS UP TO 35
KNOTS NOT OUT OF THE QUESTION. EXPECT THESE WINDS TO QUICKLY
DECREASE ON MONDAY AS A HIGH PRESSURE RIDGE SETTLES OVER THE UPPER
GREAT LAKES. SOUTHWEST WINDS OF 20 TO 25 KNOTS WILL THEN BE
POSSIBLE...MAINLY FOR THE WEST HALF OF LAKE SUPERIOR ON TUESDAY
AHEAD OF A COLD FRONT. ONCE THE FRONT PASSES TUESDAY AFTERNOON AND
EVENING...WINDS WILL VEER TO THE W/NW AND INCREASE TO 20 TO 25 KNOTS
FOR THE EAST HALF OF THE LAKE THROUGH WEDNESDAY. EXPECT WINDS TO
REMAIN BELOW 20 KNOTS FOR THE REMAINDER OF THE PERIOD.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...KLUBER
AVIATION...KC
MARINE...KC/KLUBER
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
309 PM CST SAT NOV 24 2012
.DISCUSSION...
A SHORT WAVE AND CLIPPER LIKE LOW PRESSURE SYSTEM OVER EASTERN ND
AT MID AFTERNOON WILL MOVE SOUTHEAST ACROSS THE MN/WI TONIGHT.
THERE IS A DECENT PV ANOMALY AS WELL THAT WILL PASS BETWEEN THE
TWIN CITIES AND DULUTH THIS EVENING. THIS SITUATION IS SOMEWHAT
SIMILAR TO THAT OF THURSDAY EVENING...EXCEPT THE SYSTEM TONIGHT IS
A LITTLE WEAKER AND THE ORIENTATION IS NW TO SE. PLENTY OF FORCING
AND DEEP LAYER SATURATION IS SEEN BY THE VARIOUS MODEL SOLUTIONS
PASSING ACROSS EAST CENTRAL MN AND WEST CENTRAL WI THIS EVENING.
EVEN THE SOUTHERN EDGE OF THE THALER QG INSTANTANEOUS PRECIPITATION
RATE NICKS THE TWIN CITIES THIS EVENING. HOWEVER...MUCH LIKE
THURSDAYS SNOW EVENT...THE MODEL SOLUTIONS ARE VERY DRY FOR MUCH
OF OUR CWA. THE EXCEPTION IS NEAR RUSK COUNTY WHERE A FEW
HUNDREDTHS OF AN INCH ARE SEEN.
THIS SEEMS UNREALISTIC WITH THE DEEP SATURATION SEEN COMBINED WITH
THE OMEGA AND SNOW GROWTH ALMOST COLLOCATED. GRANTED IT ONLY LASTS
FOR A FEW HOURS. RECENT RADAR TRENDS SHOWING SOME BANDING ACROSS
EASTERN ND AND NW MN WITH MID LEVEL FRONTOGENESIS EVIDENT IN THE
RAP JUST TO THE WEST. THEREFORE...USED LIKELY POPS THIS EVENING
ALONG AND EAST OF A LINE FROM MILLE LACS TO EAU CLAIRE WITH AROUND
AN INCH OF SNOW ACCUMULATION. CHANCE POPS FOR LITTLE FALLS..ST
CLOUD...THE TWIN CITIES AND RED WING WITH ACCUMULATIONS LESS THAN
AN INCH. KEPT CHANCE POPS IN PLACE OVER THE LADYSMITH AND AUGUSTA
AREAS FOR THE OVERNIGHT HOURS.
ANOTHER COLD DAY ON SUNDAY ALONG WITH BRISK NORTHWEST WINDS IN THE
WAKE OF THE LOW AND COLD FRONT. HIGHS FROM THE LOWER 20S TO LOWER 30S
FROM NORTH TO SOUTH. SKY COVER IS A LITTLE PROBLEMATIC ON SUNDAY.
THE MORNING MAY BEGIN WITH SOME SUNSHINE BUT EXTENSIVE LOW
CLOUDINESS MAY PUSH SOUTHWARD ACROSS THE FA DURING THE AFTERNOON
AND NIGHT. CONFIDENCE IS NOT HIGH AND THIS COULD AFFECT THE
OVERNIGHT LOW FOR SUNDAY NIGHT. AT THIS TIME...MONDAY SHOULD BE THE
COLDEST DAY IN THE FORECAST PERIOD AS THE LOW LEVEL COLD TROUGH
MOVES BY. HIGHS ARE ONLY FORECAST IN THE TEENS TO LOWER 20S.
THE LONGER RANGE PORTION OF THE FORECAST THROUGH NEXT SATURDAY
LOOKS DRY ALONG WITH A SLOW WARMING TREND. SOME PRECIPITATION IS
LIKELY WELL NORTH OF OUR AREA ON TUESDAY AND PERHAPS AGAIN ON
FRIDAY. BOTH THE EC AND GFS HAVE A LOW PRESSURE STORM SYSTEM
DEVELOPING OVER THE CENTRAL AND NORTHERN PLAINS NEXT WEEKEND. THIS
COULD BRING ANOTHER SURGE OF VERY MILD AIR INTO THE AREA FOR
SUNDAY AND MONDAY. 850MB TEMPS ARE PROGGED INTO THE 8-12 DEG C
RANGE. SOME EXTENDED GUIDANCE HIGHS ARE ALREADY NEAR 50 FOR THE
TWIN CITIES NEXT SATURDAY. THE NORMAL HIGH IS 32.
&&
.AVIATION... /18Z TAF ISSUANCE/
MAIN AVIATION CONCERN IS ONSET OF -SN THIS EVENING...AND HOW LOW
THE VSBYS/CIGS COULD GET DEPENDING UPON THE STRENGTH OF THE SHRTWV
MOVING ACROSS THE FA LATE THIS AFTN/EVENING.
PREVIOUS TAFS HAD -SNSH FOR MOST AREAS EXCEPT RWF... WHICH SEEMS
REASONABLE DUE TO UPSTREAM OBS AND THE STRENGTH OF THE SHRTWV.
LATEST RAP HAS A FAIRLY STRONG WAA PATTERN DEVELOPING BY 21Z-00Z
WHICH WOULD BE THE START OF SATURATION FROM THE TOP...DOWN. AFT
00Z...AS THE CONCENTRATION THE FAVORED DENDRITIC ZONE AND AMPLE
LIFT DEVELOPS...COULD SEE VSBYS DROP TO 1-2SM IN THE NE FA IN SNOW.
MAINLY AFFECTING RNH/EAU. ELSEWHERE...THE FAST NATURE OF THIS WAVE
AND LIMITED TIME TO SATURATE THE LOWER LAYERS OF THE
ATMOSPHERE...WILL ONLY HAVE -SN...WITH NO RESTRICTIONS TO VSBY.
WINDS WILL START FROM THE SOUTH...BECOME MORE SW THIS
EVENING...THEN SHIFT TO THE NW AND INCREASE OVERNIGHT...AND SUNDAY
MORNING. A FEW GUSTS OVER 20 KTS ARE POSSIBLE BY 18Z. ANOTHER
CONCERN IS WHETHER WE GET MVFR/IFR CIGS BEHIND THE FRONT LATE
TONIGHT/SUNDAY MORNING. UPSTREAM OBS IN SOUTH CENTRAL CANADA HAVE
BEEN IN THE IFR/MVFR RANGE THIS MORNING...AND THIS WOULD BE THE
SOURCE REGION AS THIS AIR MASS MOVES SE OVERNIGHT. HAVE DECIDED TO
ONLY INTRODUCE SCT012...BUT LATER SHIFTS WILL NEED TO UPDATE AS
NECESSARY.
KMSP...
AS PREVIOUSLY STATED...FAST SHRTWV ACROSS SOUTH CENTRAL CANADA WILL
PROVIDE INCREASING CLOUDINESS THIS AFTN/EVENING...WITH CLDS
LOWERING TO LOW END VFR BY 00-03Z. HAVE KEPT VSBY UNRESTRICTED AS
THE MAIN -SN SHOULD BE FURTHER TO THE E/NE OF MSP AIRFIELD...BUT
LATER SHIFTS MAY CONSIDER LOWERING THESE VSBY TO MVFR IF THE
SHRTWV IS STRONGER. WINDS WILL START FROM THE SSE...BECOME MORE
SSW THIS EVENING...THEN SHIFT TO THE NW BY MORNING...WITH GUSTS
LIKELY AFT 15-18Z. STILL NOT CONFIDENT ON MVFR CIGS BY SUNDAY
AFTN...BUT SOMETHING TO CONSIDER DUE TO THE DEPTH OF THE MOISTURE
BLW 3K IN THE LATEST MODEL RUN.
/OUTLOOK FOR KMSP/
SUN/MON...MVFR CIGS POSSIBLE WITH -SNSH. WINDS WNW AT 10G20KTS.
TUE...VFR. WINDS SSW AT 10 TO 15 KTS.
WED...VFR. WINDS NE/E AT 5 TO 10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
RAH/JLT
AREA FORECAST DISCUSSION...UPDATED
NWS DULUTH MN
1138 AM CST SAT NOV 24 2012
.AVIATION.../18Z TAF ISSUANCE/
A RIDGE OF HIGH PRESSURE IS OFFERING A SHORT WINDOW OF VFR
CONDITIONS ACROSS NE MINNESOTA AND NW WISCONSIN EARLY THIS
AFTERNOON...EXCEPT AT KHYR WHERE THERE IS LINGERING MVFR CIGS. THE
S WINDS WILL INCREASE THIS AFTERNOON AHEAD OF AN APPROACHING LOW
PRESSURE SYSTEM. CLOUDS ARE EXPECTED TO INCREASE AND CIGS LOWER FROM
WEST TO EAST THROUGH THIS AFTERNOON AND INTO THIS EVENING IN
ADVANCE OF THE APPROACHING COLD FRONT ASSOCIATED WITH SYSTEM.
THERE WILL BE PERIODS OF IFR/MVFR CONDITIONS THROUGH TONIGHT DUE
TO CIGS AND REDUCED VIS FROM THE COMBINATION OF WIND AND -SN.
THE WINDS WILL BECOME NW LATE THIS EVENING AND OVERNIGHT. THE -SN
WILL DIMINISH OR MOVE OFF TO THE EAST LATE TONIGHT AND TOMORROW
MORNING. THERE SHOULD BE LINGERING MVFR CIGS TOMORROW
MORNING.
&&
PREV DISCUSSION... /ISSUED 402 AM CST SAT NOV 24 2012/
SHORT TERM...TODAY THROUGH SUNDAY.
AT 330 AM...A VARIETY OF CONDITIONS WERE FOUND ACROSS THE
NORTHLAND. THERE WAS A LARGE AREA OF LOW CLOUDS ACROSS NW WI WITH
SOME SNOW SHOWERS. A CHECK OF WEBCAMS IN THE HURLEY AREA INDICATED
LITTLE SNOW ACTIVITY BUT LIKELY SOME SNOW SHOWERS OR FLURRIES.
THERE WAS ANOTHER AREA OF LOW CLOUDS ACROSS WESTERN AREAS OF THE
CWA WITH SOME SNOW SHOWERS AND FLURRIES AS WELL. CLEAR SKIES WERE
FOUND IN A NW TO SE AREA IN BETWEEN. TEMPERATURES RANGED FROM THE
TEENS IN CLOUDY AREAS TO THE SINGLE DIGITS ABOVE AND BELOW ZERO IN
THE CLEAR AREAS.
A STRENGTHENING SHORTWAVE AND SURFACE LOW PRESSURE SYSTEM NOW
MOVING INTO SASKATCHEWAN AND MONTANA WILL AFFECT THE WEATHER
ACROSS THE REGION STARTING THIS AFTERNOON AND CONTINUING INTO
SUNDAY. SKIES WILL BE PARTLY SUNNY FOR MOST AREAS THIS
MORNING...BUT CLOUDS WILL QUICKLY INCREASE FROM THE WEST DURING
THE DAY. A COMBINATION OF FAVORABLE JET DYNAMICS...Q-VECTOR
CONVERGENCE AND FGEN WILL PRODUCE AN INCREASE IN SNOW STARTING
THIS AFTERNOON AND CONTINUING INTO TONIGHT. THE HRRR AND 4KM WRF
SEEM TO HAVE A GOOD HANDLE ON THE EVOLUTION OF THIS SYSTEM. WILL
INCREASE POPS CONSIDERABLY ACROSS THE BOARD...WITH CATEGORICAL
POPS ACROSS THE NORTH AND LIKELY FOR MOST AREAS LATER TODAY AND
THIS EVENING. CURRENT THINKING IS THAT THERE WILL BE WIDESPREAD 1
TO 3 INCH AMOUNTS...WITH 2 TO 4 INCHES ACROSS MUCH OF NORTHERN MN.
COULD ALSO BE SOME HIGHER AMOUNTS ACROSS THE NORTH SHORE OF LAKE
SUPERIOR...AS SOUTHWEST WINDS LEND SOME OROGRAPHIC LIFT ALONG THE
NORTH SHORE. MAY NEED TO RAISE AMOUNTS THERE IN LATER FORECASTS.
DRIER AIR WILL MOVE IN BEHIND THE SYSTEM TONIGHT AND INTO
SUNDAY...WITH GUSTY WEST TO NORTHWEST WINDS BECOMING THE MAIN
STORY FOR THE NORTHLAND ON SUNDAY. COULD STILL BE SOME LINGERING
SNOW SHOWERS...ESPECIALLY ACROSS THE NORTH...AND LAKE EFFECT SNOW
SHOWERS SHOULD DEVELOP FOR THE SOUTH SHORE.
LONG TERM...SUNDAY NIGHT THROUGH SATURDAY.
NW FLOW WILL BRING A CONTINUED CAA REGIME THROUGH THE WEEKEND.
MODELS ARE IN GOOD AGREEMENT THAT H85 TEMPS FALL INTO THE NEGATIVE
UPPER TEENS TO AROUND NEGATIVE 20 C EARLY MONDAY MORNING. HAVE
LOWERED TEMPS SUNDAY NIGHT AND MONDAY TO ACCOUNT FOR THIS COLD AIR.
THE NW TRAJECTORIES AND COLD H85 TEMPS WILL BRING AN OPPORTUNITY FOR
LK EFFECT SNOW ALONG THE SOUTH SHORE OF LK SUPERIOR SUNDAY NIGHT
INTO MONDAY WHERE LIGHT SNOW ACCUMULATION WILL BE POSSIBLE ALONG THE
GOGEBIC RANGE. LATEST NAM BUFR SOUNDINGS SHOW THE STEEP LAPSE RATES
ASSOCIATED WITH THE COLD AIR...AND A SHALLOW LAYER OF
MOISTURE...REMAINS OVER THE ARROWHEAD ZONES THROUGH SUNDAY NIGHT
WHERE FLURRIES OR VERY LIGHT SHSN MAY LINGER.
LONG TERM MODELS CONTINUE TO SHOW ANOTHER SHORT WAVE DROPS OUT OF
CANADA AND SWEEPS OVER THE NORTHLAND MID-WEEK. HAVE KEPT SMALL POPS
IN THE NRN ZONES TUESDAY.
&&
.POINT TEMPS/POPS...
DLH 19 24 8 19 / 70 10 10 10
INL 15 19 6 17 / 70 10 10 10
BRD 19 25 6 17 / 30 10 10 0
HYR 20 28 10 20 / 60 10 10 0
ASX 22 30 15 22 / 70 10 20 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 4 AM CST SUNDAY
FOR LSZ140.
&&
$$
SHORT TERM...BERDES
LONG TERM....GROCHOCINSKI
AVIATION...GROCHOCINSKI
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1124 AM CST SAT NOV 24 2012
.DISCUSSION...
OVERALL IT LOOKS TO BE A QUIET UPCOMING WEEK... ALTHOUGH THERE ARE
A FEW ITEMS OF CONCERN. THE MAIN ISSUES PRESENT THEMSELVES OVER
THE FIRST 36-48 HOURS OF THE FORECAST AS WE SEE ANOTHER CHANCE FOR
SOME LIGHT SNOW ACROSS A PORTION OF THE AREA... FOLLOWED BY A
REINFORCING BLAST OF COLD AIR. IN THE BIG PICTURE... THE RIDGE OUT
WEST WILL REMAIN IN PLACE FOR THE EARLY PART OF THE WEEK AS UPPER
ENERGY CURRENTLY CRESTING IT WORKS THROUGH OUR AREA AND HELPS
MAINTAIN THE EASTERN TROUGH. HOWEVER... BY THE END OF THE WEEK THE
ECMWF AND GFS BOTH SUGGEST THE PATTERN WILL BECOME MORE ZONAL AS A
TROUGH STARTS TO SETUP OFF THE WEST COAST. INDICATIONS ARE THAT
THIS WILL EVENTUALLY LEAD TO A DECENT RIDGE OVER THE
CENTER/EASTERN PART OF THE COUNTRY TOWARD THE END OF NEXT WEEKEND
INTO THE FOLLOWING WEEK... BUT FOR NOW WE NEED NOT WORRY ABOUT
THAT AND WILL GENERALLY BE DEALING WITH BELOW NORMAL TEMPERATURES
AND DRY WEATHER.
INCREASING RETURN FLOW AND WARM ADVECTION TODAY WILL BRING
INCREASING MID-HIGH CLOUDS THROUGH THE DAY. SHORTWAVE CURRENTLY
WORKING THROUGH THE CANADIAN ROCKIES WILL DROP EAST-SOUTHEAST
LATER TODAY AND THIS EVENING AND HELP DRIVE A SURFACE LOW BY TO
OUR NORTH WHILE IT PUSHES A SURFACE TROUGH ACROSS OUR AREA. THE
BEST UPPER LEVEL DIVERGENCE AND COMBINATION OF ISENTROPIC
LIFT/SATURATION WILL STAY TO OUR NORTH... BUT WE SHOULD MANAGE TO
SEE SOME SOUTHWARD EXTENSION OF PCPN ALONG/AHEAD OF THE TROUGH
AXIS FROM LATE THIS AFTERNOON INTO TONIGHT. KEPT SOME CHANCE POPS
GOING FOR THE NORTHERN PART OF THE CWFA... AND BRACKETED THEM WITH
FLURRIES TO THE SOUTH. REMOVED THE MENTION OF FREEZING PCPN SINCE
IT APPEARS THAT ANY ELEVATED WARM LAYER WILL STAY JUST SOUTH OF
THE AREA OF PCPN. IF PCPN GETS FARTHER SOUTH THE FORECAST
SOUNDINGS FROM THE NAM AND GFS WOULD SUGGEST THAT THE ELEVATED
ABOVE 0C WARM LAYER SHOULD COOL TO THE WET BULB AND WOULD DROP
BELOW FREEZING WITH ANY PCPN. OBVIOUSLY IF THE RETURN FLOW IS
STRONG THAN EXPECTED AND THE WARM NOSE GETS FARTHER NORTH THEN
THERE COULD BE AN ISSUE WITH SOME LIGHT FZRA OR SLEET ON THE
SOUTHERN END OF THE PCPN AREA... BUT FOR NOW IT LOOKS LIKE WE
SHOULD AVOID THAT SCENARIO.
THE MAIN COLD FRONTAL BOUNDARY WILL DROP SOUTH THROUGH THE AREA
SUNDAY AFTERNOON AND EVENING... WITH A BLAST OF COLD AIR ARRIVING
FOR MONDAY. A FEW FLURRIES COULD BE SEEN IN THE WAKE OF THE
FRONT... BUT FOR NOW IT LOOKS LIKE THOSE SHOULD STAY TO OUR
NORTH/NORTHEAST AS ANTICYCLONIC BOUNDARY LAYER FLOW QUICKLY WORKS
INTO OUR AREA. WINDS WILL STAY UP SOME THROUGH THE NIGHT SUNDAY
NIGHT... WHICH WILL COMBINE WITH FALLING TEMPERATURES TO CREATE
SOME BELOW ZERO WIND CHILLS ACROSS A GOOD PART OF THE AREA.
MONDAY/S HIGHS WILL ONLY BE IN THE TEENS OVER THE NORTHWEST AND
NORTH CENTRAL PORTION OF THE AREA... WITH MOST OTHER LOCATIONS
BARELY ECLIPSING 20. IF CLOUD COVER STICKS AROUND MORE THAN
EXPECTED THEN 20 COULD EVEN BE A STRETCH. THE REMAINDER OF THE
WEEK WILL SEE PROGRESSIVELY WARMER TEMPERATURES... WITH READINGS
NEAR OR PERHAPS A BIT ABOVE NORMAL BY THE END OF THE WEEK AS
NORTHWEST UPPER FLOW BECOMES WESTERLY. THERE MAY EVENTUALLY BE A
NEED TO INCLUDE SOME CHANCE OF PCPN FOR FRIDAY WITH BOTH THE ECMWF
AND GFS SUGGESTING A SURFACE WAVE TO OUR SOUTH AND THE MAIN
BAROCLINIC ZONE LOITERING NEARBY. HOWEVER... WITH VIRTUALLY NO
RETURN FLOW INTO THE REGION THROUGH THE WEEK... IT IS TOO EARLY TO
HAVE MUCH FAITH IN ANY PCPN BEING GENERATED AT THIS POINT.
&&
.AVIATION.../18Z TAF ISSUANCE/
MAIN AVIATION CONCERN IS ONSET OF -SN THIS EVENING...AND HOW LOW
THE VSBYS/CIGS COULD GET DEPENDING UPON THE STRENGTH OF THE SHRTWV
MOVING ACROSS THE FA LATE THIS AFTN/EVENING.
PREVIOUS TAFS HAD -SNSH FOR MOST AREAS EXCEPT RWF... WHICH SEEMS
REASONABLE DUE TO UPSTREAM OBS AND THE STRENGTH OF THE SHRTWV.
LATEST RAP HAS A FAIRLY STRONG WAA PATTERN DEVELOPING BY 21Z-00Z
WHICH WOULD BE THE START OF SATURATION FROM THE TOP...DOWN. AFT
00Z...AS THE CONCENTRATION THE FAVORED DENDRITIC ZONE AND AMPLE
LIFT DEVELOPS...COULD SEE VSBYS DROP TO 1-2SM IN THE NE FA IN SNOW.
MAINLY AFFECTING RNH/EAU. ELSEWHERE...THE FAST NATURE OF THIS WAVE
AND LIMITED TIME TO SATURATE THE LOWER LAYERS OF THE
ATMOSPHERE...WILL ONLY HAVE -SN...WITH NO RESTRICTIONS TO VSBY.
WINDS WILL START FROM THE SOUTH...BECOME MORE SW THIS
EVENING...THEN SHIFT TO THE NW AND INCREASE OVERNIGHT...AND SUNDAY
MORNING. A FEW GUSTS OVER 20 KTS ARE POSSIBLE BY 18Z. ANOTHER
CONCERN IS WHETHER WE GET MVFR/IFR CIGS BEHIND THE FRONT LATE
TONIGHT/SUNDAY MORNING. UPSTREAM OBS IN SOUTH CENTRAL CANADA HAVE
BEEN IN THE IFR/MVFR RANGE THIS MORNING...AND THIS WOULD BE THE
SOURCE REGION AS THIS AIR MASS MOVES SE OVERNIGHT. HAVE DECIDED TO
ONLY INTRODUCE SCT012...BUT LATER SHIFTS WILL NEED TO UPDATE AS
NECESSARY.
KMSP...
AS PREVIOUSLY STATED...FAST SHRTWV ACROSS SOUTH CENTRAL CANADA WILL
PROVIDE INCREASING CLOUDINESS THIS AFTN/EVENING...WITH CLDS
LOWERING TO LOW END VFR BY 00-03Z. HAVE KEPT VSBY UNRESTRICTED AS
THE MAIN -SN SHOULD BE FURTHER TO THE E/NE OF MSP AIRFIELD...BUT
LATER SHIFTS MAY CONSIDER LOWERING THESE VSBY TO MVFR IF THE
SHRTWV IS STRONGER. WINDS WILL START FROM THE SSE...BECOME MORE
SSW THIS EVENING...THEN SHIFT TO THE NW BY MORNING...WITH GUSTS
LIKELY AFT 15-18Z. STILL NOT CONFIDENT ON MVFR CIGS BY SUNDAY
AFTN...BUT SOMETHING TO CONSIDER DUE TO THE DEPTH OF THE MOISTURE
BLW 3K IN THE LATEST MODEL RUN.
/OUTLOOK FOR KMSP/
SUN/MON...MVFR CIGS POSSIBLE WITH -SNSH. WINDS WNW AT 10G20KTS.
TUE...VFR. WINDS SSW AT 10 TO 15 KTS.
WED...VFR. WINDS NE/E AT 5 TO 10 KTS. ..JLT..
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
TRH/JLT