Forecast Discussions mentioning any of
"HRRR" "RR" "RUC13" "RUC" received at GSD on 03/02/12
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
659 PM MST THU MAR 1 2012
.UPDATE...CONVECTION IS MAKING FOR A DIFFICULT FORECAST
TONIGHT...AND SIMILAR DIFFICULTY ALL THE WAY THROUGH FRIDAY.
LATEST SURFACE ANALYSIS SHOWS A STRONG ANTICYCLONE ACROSS
NORTHEAST COLORADO. THIS HAS BROUGHT DOWNSLOPING SOUTHEAST WINDS
TO DENVER...WHILE RATHER STRONG LOW LEVEL CONVERGENCE HAS
DEVELOPED IN THE FORT COLLINS TO NORTHERN WELD COUNTY AREA WHERE
CONVECTION HAS BLOSSOMED IN THE LAST HOUR. POCKETS OF 25-35 DBZ
ECHOES LIKELY RESULTING IN POCKETS OF HEAVY SNOW WITH AT LEAST 1
INCH PER HOUR RATES. QUESTION IS HOW THIS EVOLVES OVERNIGHT...AND
LATEST MESOSCALE MODELS INCLUDING THE ARW AND NMM SHOW THIS
PUSHING SOUTHEAST IN SIMILAR FASHION TO THE NAM. MEANWHILE...RUC13
AND HRRR HAD NO CLUE WHERE SNOW IS EVEN OCCURRING AT THE PRESENT
TIME. FEEL THE LATEST 4KM WRF MIGHT HAVE THE BETTER HANDLE ON IT
CONSIDERING THE LATEST SURFACE ANALYSIS...KEEPING THE HEAVIEST
SNOW IN LARIMER AND WELD COUNTIES BEFORE WEAKENING AS IT SPREADS
SOUTHEAST TO THE DENVER METRO AREA. THERE IS A LOT OF UNCERTAINTY
WITH THIS FORECAST...BUT ANYWHERE CONVECTION IS MORE PERSISTENT
COULD REQUIRE AN ADVISORY. WE WILL HAVE TO MONITOR THROUGH THE
REST OF THE NIGHT. BAND OF SNOW OR REDEVELOPMENT OF CONVECTION IS
FAIRLY LIKELY BEHIND THE NEXT COLD FRONT DROPPING SOUTHWARD ACROSS
THE PLAINS AROUND DAYBREAK FRIDAY...SO CONVECTIVE SNOW MAY
REDEVELOP WITH EVEN SOME CAPE NOTED ON FORECAST SOUNDINGS. MIGHT
HAVE TO ISSUE AN ADVISORY FOR DENVER METRO FOR THE DAY FRIDAY IF
WINDS CAN TURN INTO THE HILLS JUST ENOUGH. PALMER DIVIDE AND
SOUTHERN FOOTHILLS ARE STILL SETTING UP THE BEST.
&&
.AVIATION...CONVECTIVE SNOW SHOWERS TO THE NORTHWEST OF THE DENVER
METRO AREA AIRPORTS WILL HAVE TO BE WATCHED. AT THE CURRENT
TIME...WE DO THINK THESE SHOWERS WILL GRADUALLY WEAKEN AS THEY
PUSH TOWARD KDEN...KBJC...AND KAPA BY 03Z-06Z...BUT IFR/LIFR
CONDITIONS WOULD BE POSSIBLE WITH A QUICK INCH OF ACCUMULATION.
REST OF FORECAST UNCHANGED WITH POTENTIAL FOR MORE WIDESPREAD SNOW
FRIDAY MORNING.
&&
.PREV DISCUSSION... /ISSUED 503 PM MST THU MAR 1 2012/
UPDATE...SNOW HAS NOT MATERIALIZED ACROSS URBAN CORRIDOR AS
PREVIOUSLY THOUGHT. AFTER THE INCREASE IN UPSLOPE EARLIER THIS
AFTERNOON...THE UPSLOPE HAS WEAKEND OR BECOME NON EXISTANT AND
ECHOES HAVE MOSTLY DISSIPATED. STILL SOME ECHOES ACROSS PALMER
DIVIDE HEADING INTO LINCOLN COUNTY. SNOW SHOWERS STILL POSSIBLE
THROUGH TONIGHT...MAINLY THIS EVENING QG ASCENT MOVES ACROSS THE
REGION. BUT THESE SHOWERS WILL MAINLY BE LIGHT ACROSS THE
PLAINS...WITH LITTLE OR NO IMPACT. BEST CHANCE FOR THESE SHOWERS
STILL LOOK TO BE ALONG THE PALMER DIVIDE AND SOUTHERN FOOTHILLS.
SO MAIN CHANGE FOR THIS UPDATE WILL BE TO DROP ADVISORY FOR ZONES
39 AND 40...DECREASE POPS AND SNOW AMOUNTS. NOW LOOKS LIKE BEST
CHANCE OF ACCUMULATING SNOW SHIFTING TOWARD THE MORNING HOURS
FRIDAY BEHIND SURFACE FRONT. HILITES FOR MOUNTAINS STILL LOOK ON
TRACK
AVIATION...SNOW CHANCES ACROSS AREA THIS EVENING HAVE DECREASED.
AS A RESULT...VFR CONDITIONS TO PREVAIL WITH A CHANCE FOR MVFR
BETWEEN 02Z AND 05Z WITH PASSING SNOW SHOWERS. NEXT WAVE STILL
EXPECTED TO AFFECT AREA IN THE 10Z TO 16Z TIME FRAME WITH A BETTER
CHANCE FOR SNOWFALL AND MVFR CONDITIONS.
PREV DISCUSSION... /ISSUED 341 PM MST THU MAR 1 2012/
SHORT TERM...MOIST NORTHWEST FLOW ALOFT CONTINUES ACROSS THE
REGION THROUGH FRIDAY. AFTER A BRIEF DECREASE IN MOUNTAIN
SNOW...WEB CAMS AS WELL AS RADAR SHOW THE SNOW HAS INCREASED
AGAIN. WATER VAPOR LOOPS SHOW SOME SORT OF SHORTWAVE MOVING INTO
WESTERN COLORADO WHICH MAY BE AIDING IN THE SNOW INCREASE. THE
MOUNTAIN WARNINGS AND ADVISORIES STILL WARRANTED THROUGH TONIGHT.
THOUGH THERE MAY BE A BIT OF A DECREASE AGAIN OVERNIGHT AS SHOWN
BY THE LATEST RUC AND HRR RUNS. AS FOR PLAINS... STILL A BIT OF A
TRICKY FORECAST THIS EVENING AS MOST MODELS NOT HANDLING THINGS
WELL IN THE SHORT TERM. AIRMASS STILL A BIT UNSTABLE AND LOCAL
ACARS SOUNDINGS HAVE SHOWN A DEEPENING UPSLOPE. EARLIER SNOWBAND
HAS HELPED TO MOISTEN THE LOWER LAYERS. RADAR SHOWING ECHOES ALONG
FOOTHILLS AND URBAN CORRIDOR AS FAR NORTH AS LARIMER COUNTY...WITH
MOST OF THE ACTIVITY OVER JEFFERSON AND DOUGLAS COUNTIES. SO MOST
AREAS IN AND NEAR URBAN CORRIDOR SHOULD SEE SNOW SOON. AS
TEMPERATURES GET COLDER THIS EVENING...SHOULD ALSO SEE SOME
ACCUMULATING SNOW. ADVISORY FOR SOUTHERN FOOTHILLS AND PORTIONS OF
URBAN CORRIDOR STILL LOOKING ON TRACK. SHOULD SEE SOME BREAK IN
THE SNOWFALL TOWARDS 06Z...BASED ON THOSE RUC AND HRR RUNS. NEXT
WAVE LOOKS TO MOVE INTO THE AREA SATURDAY MORNING WHICH SHOULD
INCREASE THE SNOWFALL ACROSS THE REGION. WARNING AND ADVISORIES
FOR THE MOUNTAINS CONTINUE THROUGH FRIDAY...LOOKS REASONABLE. AS
FOR PLAINS...BEST CHANCE FOR SNOW TO BE IN THE 10Z-16Z AS THE LIFT
COMBINES WITH NORTHERLY FLOW...WITH THE BEST AREA IN ZONES 36 AND
41. FLOW BECOMES NORTHWEST DURING THE AFTERNOON...WITH DRIER AIR
WORKING ACROSS THE AREA. SHOULD SEE A DECREASE IN SNOW BY THE
AFTERNOON. OVERALL...CURRENT SNOW AMOUNTS STILL LOOK ON TRACK.
LONG TERM...BY FRIDAY EVENING PRECIP SHOULD BE ON THE DECLINE
BOTH IN THE MTNS AND ALONG THE PALMER DIVIDE WITH SUBSIDENCE ON
THE BACK SIDE OF THE PASSING UPPER TROUGH. HOWEVER WEST-NORTHWEST
MID-LEVEL FLOW SHOULD CONTINUE TO PRODUCE AREAS OF OROGRAPHIC
SNOWFALL ROUGHLY ALONG AND WEST OF THE CONTINENTAL DIVIDE THROUGH
SATURDAY EVENING. DO NOT SEE MUCH IF ANY NEW ACCUMULATION.
OTHERWISE THIS SAME FLOW WILL DRY THINGS IN THE LOWER ATMOSPHERE
EAST OF THE MTNS ON SATURDAY. HOWEVER PASSING MID-LEVEL MOISTURE
IS EXPECTED TO PRODUCE PARTLY TO MOSTLY CLOUDY SKIES FOR MUCH OF
THE DAY. CLOUDS NOT EXPECTED TO DELAY WARMUP WITH MAX TEMPS ON
THE PLAINS 8-14F WARMER THAN READINGS ON FRIDAY.
FOR SUNDAY AND BEYOND...UPPER RIDGE BUILDING OVER THE GREAT BASIN
MIGRATES SLOWLY EASTWARD OVER THE ROCKY MTN REGION WITH HIGHEST
HEIGHTS...WARMEST TEMPS ALOFT...OVER COLORADO MONDAY/MONDAY
NIGHT. COULD SEE MAX TEMPS AS MUCH AS 10DEG F ABOVE AVERAGE FOR
THE DATE. WINDS NOT MUCH OF A CONCERN SUNDAY-TUESDAY. THEN BY
MID-WEEK...MEDIUM RANGE MODELS SHOW THIS RIDGE MOVING EAST AND
THE NEXT POTENT UPPER AIR TROUGH MOVING OVER THE GREAT BASIN.
SHOULD THIS OCCUR COULD SEE SNOW CHANCES RETURNING TO THE HIGH
COUNTRY AND THE DEVELOPMENT OF STG/GUSTY SOUTH-SOUTHWESTERLY
WINDS BOTH MTNS AND PLAINS.
AVIATION...SNOW DEVELOPING AGAIN ACROSS DENVER AREA...SHOULD
PERSIST THROUGH MUCH OF THE EVENING. MVFR CONDITIONS SHOULD
PREVAIL THROUGH 03Z WITH A CHANCE FOR IFR IN HEAVIER SNOW BANDS.
SHOULD SEE CONDITIONS IMPROVE TO VFR AFTER 03Z...THOUGH CEILINGS
AROUND 5000 FEET AGL WILL PREVAIL. NEXT WAVE TO AFFECT AREA AROUND
10Z WITH MVFR CONDITIONS REDEVELOPING AS SNOW SPREADS BACK INTO
REGION. DRIER AIR TO MOVE INTO THE AREA AFTER 16Z AS WINDS BECOME
NORTHWEST. VFR TO PREVAIL THROUGH THE AFTERNOON.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 5 PM MST FRIDAY FOR COZ033-034.
WINTER WEATHER ADVISORY UNTIL 5 PM MST FRIDAY FOR COZ036-041.
WINTER STORM WARNING UNTIL 5 PM MST FRIDAY FOR COZ031.
&&
$$
SHORT TERM...BARJENBRUCH
LONG TERM....MEIER
AVIATION...BARJENBRUCH
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
503 PM MST THU MAR 1 2012
CORRECTED HEADLINES IN WATCHES/WARNINGS/ADVISORIES SECTION
.UPDATE...SNOW HAS NOT MATERIALIZED ACROSS URBAN CORRIDOR AS
PREVIOUSLY THOUGHT. AFTER THE INCREASE IN UPSLOPE EARLIER THIS
AFTERNOON...THE UPSLOPE HAS WEAKEND OR BECOME NON EXISTANT AND
ECHOES HAVE MOSTLY DISSIPATED. STILL SOME ECHOES ACROSS PALMER
DIVIDE HEADING INTO LINCOLN COUNTY. SNOW SHOWERS STILL POSSIBLE
THROUGH TONIGHT...MAINLY THIS EVENING QG ASCENT MOVES ACROSS THE
REGION. BUT THESE SHOWERS WILL MAINLY BE LIGHT ACROSS THE
PLAINS...WITH LITTLE OR NO IMPACT. BEST CHANCE FOR THESE SHOWERS
STILL LOOK TO BE ALONG THE PALMER DIVIDE AND SOUTHERN FOOTHILLS.
SO MAIN CHANGE FOR THIS UPDATE WILL BE TO DROP ADVISORY FOR ZONES
39 AND 40...DECREASE POPS AND SNOW AMOUNTS. NOW LOOKS LIKE BEST
CHANCE OF ACCUMULATING SNOW SHIFTING TOWARD THE MORNING HOURS
FRIDAY BEHIND SURFACE FRONT. HILITES FOR MOUNTAINS STILL LOOK ON
TRACK
&&
.AVIATION...SNOW CHANCES ACROSS AREA THIS EVENING HAVE DECREASED.
AS A RESULT...VFR CONDITIONS TO PREVAIL WITH A CHANCE FOR MVFR
BETWEEN 02Z AND 05Z WITH PASSING SNOW SHOWERS. NEXT WAVE STILL
EXPECTED TO AFFECT AREA IN THE 10Z TO 16Z TIME FRAME WITH A BETTER
CHANCE FOR SNOWFALL AND MVFR CONDITIONS.
&&
.PREV DISCUSSION... /ISSUED 341 PM MST THU MAR 1 2012/
SHORT TERM...MOIST NORTHWEST FLOW ALOFT CONTINUES ACROSS THE
REGION THROUGH FRIDAY. AFTER A BRIEF DECREASE IN MOUNTAIN
SNOW...WEB CAMS AS WELL AS RADAR SHOW THE SNOW HAS INCREASED
AGAIN. WATER VAPOR LOOPS SHOW SOME SORT OF SHORTWAVE MOVING INTO
WESTERN COLORADO WHICH MAY BE AIDING IN THE SNOW INCREASE. THE
MOUNTAIN WARNINGS AND ADVISORIES STILL WARRANTED THROUGH TONIGHT.
THOUGH THERE MAY BE A BIT OF A DECREASE AGAIN OVERNIGHT AS SHOWN
BY THE LATEST RUC AND HRR RUNS. AS FOR PLAINS... STILL A BIT OF A
TRICKY FORECAST THIS EVENING AS MOST MODELS NOT HANDLING THINGS
WELL IN THE SHORT TERM. AIRMASS STILL A BIT UNSTABLE AND LOCAL
ACARS SOUNDINGS HAVE SHOWN A DEEPENING UPSLOPE. EARLIER SNOWBAND
HAS HELPED TO MOISTEN THE LOWER LAYERS. RADAR SHOWING ECHOES ALONG
FOOTHILLS AND URBAN CORRIDOR AS FAR NORTH AS LARIMER COUNTY...WITH
MOST OF THE ACTIVITY OVER JEFFERSON AND DOUGLAS COUNTIES. SO MOST
AREAS IN AND NEAR URBAN CORRIDOR SHOULD SEE SNOW SOON. AS
TEMPERATURES GET COLDER THIS EVENING...SHOULD ALSO SEE SOME
ACCUMULATING SNOW. ADVISORY FOR SOUTHERN FOOTHILLS AND PORTIONS OF
URBAN CORRIDOR STILL LOOKING ON TRACK. SHOULD SEE SOME BREAK IN
THE SNOWFALL TOWARDS 06Z...BASED ON THOSE RUC AND HRR RUNS. NEXT
WAVE LOOKS TO MOVE INTO THE AREA SATURDAY MORNING WHICH SHOULD
INCREASE THE SNOWFALL ACROSS THE REGION. WARNING AND ADVISORIES
FOR THE MOUNTAINS CONTINUE THROUGH FRIDAY...LOOKS REASONABLE. AS
FOR PLAINS...BEST CHANCE FOR SNOW TO BE IN THE 10Z-16Z AS THE LIFT
COMBINES WITH NORTHERLY FLOW...WITH THE BEST AREA IN ZONES 36 AND
41. FLOW BECOMES NORTHWEST DURING THE AFTERNOON...WITH DRIER AIR
WORKING ACROSS THE AREA. SHOULD SEE A DECREASE IN SNOW BY THE
AFTERNOON. OVERALL...CURRENT SNOW AMOUNTS STILL LOOK ON TRACK.
LONG TERM...BY FRIDAY EVENING PRECIP SHOULD BE ON THE DECLINE
BOTH IN THE MTNS AND ALONG THE PALMER DIVIDE WITH SUBSIDENCE ON
THE BACK SIDE OF THE PASSING UPPER TROUGH. HOWEVER WEST-NORTHWEST
MID-LEVEL FLOW SHOULD CONTINUE TO PRODUCE AREAS OF OROGRAPHIC
SNOWFALL ROUGHLY ALONG AND WEST OF THE CONTINENTAL DIVIDE THROUGH
SATURDAY EVENING. DO NOT SEE MUCH IF ANY NEW ACCUMULATION.
OTHERWISE THIS SAME FLOW WILL DRY THINGS IN THE LOWER ATMOSPHERE
EAST OF THE MTNS ON SATURDAY. HOWEVER PASSING MID-LEVEL MOISTURE
IS EXPECTED TO PRODUCE PARTLY TO MOSTLY CLOUDY SKIES FOR MUCH OF
THE DAY. CLOUDS NOT EXPECTED TO DELAY WARMUP WITH MAX TEMPS ON
THE PLAINS 8-14F WARMER THAN READINGS ON FRIDAY.
FOR SUNDAY AND BEYOND...UPPER RIDGE BUILDING OVER THE GREAT BASIN
MIGRATES SLOWLY EASTWARD OVER THE ROCKY MTN REGION WITH HIGHEST
HEIGHTS...WARMEST TEMPS ALOFT...OVER COLORADO MONDAY/MONDAY
NIGHT. COULD SEE MAX TEMPS AS MUCH AS 10DEG F ABOVE AVERAGE FOR
THE DATE. WINDS NOT MUCH OF A CONCERN SUNDAY-TUESDAY. THEN BY
MID-WEEK...MEDIUM RANGE MODELS SHOW THIS RIDGE MOVING EAST AND
THE NEXT POTENT UPPER AIR TROUGH MOVING OVER THE GREAT BASIN.
SHOULD THIS OCCUR COULD SEE SNOW CHANCES RETURNING TO THE HIGH
COUNTRY AND THE DEVELOPMENT OF STG/GUSTY SOUTH-SOUTHWESTERLY
WINDS BOTH MTNS AND PLAINS.
AVIATION...SNOW DEVELOPING AGAIN ACROSS DENVER AREA...SHOULD
PERSIST THROUGH MUCH OF THE EVENING. MVFR CONDITIONS SHOULD
PREVAIL THROUGH 03Z WITH A CHANCE FOR IFR IN HEAVIER SNOW BANDS.
SHOULD SEE CONDITIONS IMPROVE TO VFR AFTER 03Z...THOUGH CEILINGS
AROUND 5000 FEET AGL WILL PREVAIL. NEXT WAVE TO AFFECT AREA AROUND
10Z WITH MVFR CONDITIONS REDEVELOPING AS SNOW SPREADS BACK INTO
REGION. DRIER AIR TO MOVE INTO THE AREA AFTER 16Z AS WINDS BECOME
NORTHWEST. VFR TO PREVAIL THROUGH THE AFTERNOON.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 5 PM MST FRIDAY FOR COZ033-034.
WINTER WEATHER ADVISORY UNTIL 5 PM MST FRIDAY FOR COZ036-041.
WINTER STORM WARNING UNTIL 5 PM MST FRIDAY FOR COZ031.
&&
$$
SHORT TERM...D-L
LONG TERM....BAKER
AVIATION...D-L
AREA FORECAST DISCUSSION...UPDATED
NWS PUEBLO CO
522 PM MST THU MAR 1 2012
.UPDATE...
COLD FRONT STARTING TO PUSH INTO THE EXTREME SOUTHERN PORTIONS OF
THE SOUTHEAST PLAINS...INTO LAS ANIMAS AND BACA COUNTIES. FALLING
TEMPERATURES AND INCREASING HUMIDITIES SHOULD BRING A QUICK END
TO THE RED FLAG WARNING FOR THOSE AREAS...WITH KTAD ALREADY ABOVE
THE CRITICAL RH THRESHOLD...AND KSPD NEARING THAT. THUS HAVE UPDATED
TO ALLOW THE RED FLAG WARNING TO EXPIRE. HAVE ALSO UPDATED GRIDS
TO REFLECT CURRENT TEMPERATURES/HUMIDITIES/WINDS BEHIND THE FRONT
WHICH MOVED THROUGH FASTER THAN NAM12 HAD SUGGESTED. HRRR APPEARS
TO HAVE A GOOD HANDLE ON IT...AND LEANED HEAVILY ON IT FOR GRID
PRODUCTION. OTHERWISE...POPS SEEM IN GOOD SHAPE. WITH CONVECTIVE
NATURE OF SNOW...WOULDN`T BE SURPRISED TO SEE A QUICK INCH OR TWO OF
SNOW ACROSS SOUTHERN EL PASO AND NORTHERN PUEBLO COUNTIES OVER THE
NEXT COUPLE HOURS BEFORE SHORTWAVE PUSHES EASTWARD. -KT
&&
.PREV DISCUSSION... /ISSUED 341 PM MST THU MAR 1 2012/
SHORT TERM...
(TONIGHT AND FRIDAY)
BROAD UPPER TROUGH REMAINS ACROSS THE INTERMOUNTAIN WEST WITH AN
EMBEDDED SHORT WAVE LIFTING OUT ACROSS THE CENTRAL ROCKIES AS
SECONDARY ENERGY IS DIGGING INTO THE NORTH GREAT BASIN AT THIS TIME.
AT THE SFC...BOUNDARY ASSOCIATED WITH CENTRAL ROCKIES SHORT WAVE
CURRENTLY VISIBLE ON KPUX RADAR BANKED UP ACROSS THE LOWER EASTERN
SLOPES OF RAMPART RANGE BACK THROUGH NORTHEASTERN PUEBLO COUNTY AND
INTO CENTRAL OTERO...BENT AND PROWERS COUNTIES AT THIS TIME. GUSTY
WESTERLY WINDS CONTINUE SOUTH OF THE BOUNDARY...KEEPING RED FLAG
CONDITIONS IN PLACE ACROSS THE SOUTHERN TIER ZONES AT THIS TIME.
TONIGHT AND FRIDAY...FIRST EMBEDDED WAVE CONTINUES TO LIFT OUT INTO
THE CENTRAL HIGH PLAINS THIS EVENING ALLOWING FOR FRONTAL BOUNDARY
TO CONTINUE TO SLIDE SOUTH AND WEST ACROSS ALL OF THE EASTERN PLAINS
THROUGH THE LATE EVENING. PASSING WAVE WILL KEEP SNOW...HEAVY AT
TIMES...ACROSS THE MTS OF THE CONTINENTAL DVD THROUGH THE
EVENING...WITH A SHORT LULL IN SNOWFALL EXPECTED LATER TONIGHT.
PASSING WAVE AND FRONT WILL ALSO PROVIDE LIFT FOR LIGHT SNOWFALL
ACROSS THE REST OF THE HIGHER TERRAIN AND ACROSS THE EASTERN PLAINS
THIS EVENING WITH BEST POPS ACROSS THE HIGHER ELEVATIONS OF THE
EASTERN MTS AND ACROSS THE PALMER DVD WITH NORTHERLY UPSLOPE WINDS
BEHIND FRONT. SHOULD ALSO SEE PRECIPITATION DIMINISHING ACROSS THE
EASTERN MTS AND PLAINS LATER TONIGHT...THROUGH COULD CONTINUE TO
SEE LIGHT SNOW ACROSS EASTERN SLOPES AND IMMEDIATE ADJACENT PLAINS
WITH GENERALLY WEAK MOIST LOW LEVEL UPSLOPE FLOW.
SECONDARY WAVE CONTINUES TO DIG ACROSS THE GREAT BASIN LATE TONIGHT
WHICH IS THEN PROGGED TO CONTINUE ACROSS THE STATE THROUGH THE DAY
TOMORROW...PROVIDING ANOTHER ROUND OF SNOWFALL TO THE MTS AND
IMMEDIATE ADJACENT PLAINS...AS A SECONDARY NORTHERLY SURGE OF COLD
AIR MOVES ACROSS EASTERN COLORADO. WITH THAT SAID...HAVE UPGRADED
AND ISSUED WINTER STORM WARNINGS FOR THE HIGHER ELEVATIONS OF THE
EASTERN MTS...AND THE PALMER DVD AND HAVE KEPT CURRENT HIGHLIGHTS IN
PLACE ACROSS THE CENTRAL AND SOUTHWEST MTS. LATEST LOCAL WRF DATA
INDICATING A MORE EASTERLY SFC-H7 FLOW ACROSS THE I-25 CORRIDOR
THROUGH THE DAY TOMORROW...WHICH WOULD BRING MORE SNOWFALL THAN
CURRENTLY FORECAST TO SOUTHERN PORTIONS OF EL PASO COUNTY...NORTHERN
PUEBLO COUNTY AND FREMONT COUNTY...AS WELL AS THE SOUTHERN I-25
CORRIDOR...THOUGH WILL LET THE NEXT SHIFTS GET A LOOK AT NEWER DATA
TO DECIDE ON ANY ADDITIONAL HIGHLIGHTS. -MW
LONG TERM...
FRI NITE - THU)
..STORM MOVING OUT AT THE BEGINNING OF THIS PERIOD...AND A NEW
STORM MOVING IN AT THE END OF THIS PERIOD...QUIET IN-BETWEEN...
THE HEADLINE ABOVE PRETTY MUCH TELLS THE STORY OF THE WEATHER
BETWEEN FRIDAY NIGHT INTO NEXT THURSDAY. STORM WHICH HAS BEEN
BRINGING SNOW TO THE CONTDVD AND PROMISES TO BRING SOME NEEDED
PRECIP TO THE E MTNS...I-25 CORRIDOR REGION...WILL BE MOVING OUT OF
THE AREA FRIDAY EVENING. SNOW WILL LIKELY BE STILL GOING ACROSS THE
RATON MESA REGION EARLY FRIDAY EVENING BUT SHOULD CLEAR OUT OF THE
AREA BY MIDNIGHT.
FROM SAT THRU TUESDAY...IT WILL BE MAINLY DRY OVER THE REGION
THROUGH THE PERIOD. THE ONLY EXCEPTION WILL BE ACROSS THE C MTNS
WERE SOME SNOW SHOWERS WILL BE POSSIBLE AT THE HIGHEST ELEVATIONS.
ACROSS THE REMAINDER OF THE AREA...TEMPERATURES WILL BE WARMING UP
QUITE A BIT....WITH TEMPS ON THE PLAINS AROUND 50F SAT...AROUND 60
SUNDAY...U60S MONDAY...AND AROUND 70 TUESDAY. BY WEDNESDAY...THE
NEXT BIG PACIFIC TROUGH WILL BE MOVING INTO THE REGION AND THIS
SYSTEM ONCE AGAIN PROMISES TO BRING SNOW TO THE C MTNS AND POSSIBLY
LOWER ELEVATIONS BY MID TO LATE WEEK. THERE IS STILL SOME
UNCERTAINTY THIS FAR OUT AND ONLY SLIGHT POPS ARE MENTIONED AT THE
HIGHER ELEVATIONS DURING THE MID WEEK TIME PD...BUT IF THE MODELS
CONTINUE TO SHOW CONSISTENCY...THEN POP VALUES WILL HAVE TO BE
RAMPED UP.
WITH ANOTHER STRONG TROUGH POSSIBLE AND LAPSE RATES INCREASING WITH
THE INCREASING SUN ANGLE...WE WILL LIKELY BE DEALING WITH MORE FIRE
WX ISSUES TUES AND WEDNESDAY. /34
AVIATION...
RADAR DATA AND OBS INDICATING SFC BOUNDARY PUSHED THROUGH KPUB AND
TRAILS BACK SOUTH AND EAST FROM SOUTH OF KLHX TO NORTH OF KSPD.
FRONT WILL CONTINUE TO SLIDE SOUTH AND WEST ACROSS THE REST OF THE
PAINS THIS EVENING...WITH LOW LEVEL UPSLOPE FLOW PERSISTING
OVERNIGHT. GUSTY NORTH TO NORTHEAST WINDS 15-30KTS AT KCOS AND KPUB
WILL BE COME MORE EASTERLY AND DIMINISH AFT 06Z. MVFR CONDITIONS
WITH SCATTERED SHOWERS AT BOTH TERMINALS THROUGH 06Z WITH UPSLOPE
KEEP MVFR AND LOCAL IFR CIGS ACROSS KCOS AND KPUB THROUGH THE EARLY
MORNING WHEN A SECONDARY COLD FRONT WILL BRING GUSTY NORTHERLY WINDS
AND CHANCES OF SNOW TO BOTH TERMINALS THROUGH 18Z. KALS...WILL
CONTINUE TO SEE GUSTY WEST TO SOUTHWEST WINDS THROUGH 06Z ALONG WITH
BRIEF MVFR CONDITIONS IN PASSING SHOWERS. -MW
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 11 AM MST FRIDAY FOR COZ059-061-
063.
WINTER WEATHER ADVISORY UNTIL 11 PM MST FRIDAY FOR COZ072-074-
079.
WINTER STORM WARNING UNTIL 11 AM MST FRIDAY FOR COZ058-060.
WINTER STORM WARNING UNTIL 11 PM MST FRIDAY FOR COZ073-075-080.
WINTER WEATHER ADVISORY UNTIL 2 PM MST FRIDAY FOR COZ064-067.
WINTER STORM WARNING UNTIL 2 PM MST FRIDAY FOR COZ066-068.
WINTER WEATHER ADVISORY UNTIL 5 PM MST FRIDAY FOR COZ081-084.
WINTER STORM WARNING UNTIL 5 PM MST FRIDAY FOR COZ082.
&&
$$
31/88
AREA FORECAST DISCUSSION
NWS TAUNTON MA
1026 PM EST THU MAR 1 2012
.SYNOPSIS...
LOW PRESSURE RACING ACROSS NEW ENGLAND WILL MOVE OFF TO THE EAST
TONIGHT. HIGH PRESSURE WILL BRING DRY WEATHER OVERNIGHT AND
FRIDAY. STRONG LOW PRESSURE WILL MOVE THROUGH THE GREAT LAKES LATE
FRIDAY INTO FRIDAY NIGHT AND SWING A COLD FRONT THROUGH NEW
ENGLAND SATURDAY. MAINLY DRY AND COLDER WEATHER WILL FOLLOW EARLY
NEXT WEEK...THEN A SIGNIFICANT WARMING TREND IS POSSIBLE TOWARD
MIDDLE AND END OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
10 PM UPDATE...
SNOW CONTINUES TO DIMINISH ACROSS SOUTHERN NEW ENGLAND THIS
EVENING. THE MAJORITY OF THE LINGERING SNOW CONFINED INSIDE OF
I-495 ACROSS EASTERN MA...SOUTHEAST MA AND CAPE COD AND THE
ISLANDS. 01/23Z HRRR LOOKS REALLY GOOD TIMING-WISE WITH ITS
HANDLING OF THE BACK EDGE OF THE SNOW. USED IT TO MAKE ADJUSTMENTS
TO THE FORECAST THIS EVENING.
PREVIOUS DISCUSSION...
COASTAL FRONT SLOWLY MOVING SOUTH AND EAST ALONG THE COASTAL PLAIN
WITH TEMPS FALLING SHARPLY BELOW FREEZING AND INTO THE 20S AFTER
WIND SHIFT TO N. ISSUED SPS TO ADDRESS FALLING TEMPS AND
SUBSEQUENT ICY ROADS.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH 6 PM FRIDAY/...
HIGH PRESSURE OVER THE MIDWEST MOVES OVER NEW ENGLAND FRIDAY
MORNING. WE EXPECT PARTIAL CLEARING...BUT LINGERING MOISTURE BELOW
850 MB SUGGESTS PARTLY TO MOSTLY CLOUDY SKIES DURING THE DAY.
MEANWHILE...INCREASING MOISTURE AT HIGH LEVELS IN THE WARM
ADVECTION AHEAD OF THE NEXT SYSTEM. SO EXPECT INCREASING HIGH
CLOUDS OVER THE TOP OF ANY LOW CLOUDS.
925 MB TEMPS OF -2C TO -4C SUPPORT MAX TEMPS IN THE MID 30S TO
AROUND 40. A BLEND OF MOS ACHIEVED THIS RANGE.
&&
.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
HIGHLIGHTS...
* MIXED PRECIP AND ICE INTERIOR FRI NIGHT CHANGING TO RAIN.
* MILD WITH SHOWERS FOR SATURDAY
* MUCH COLDER WITH BELOW NORMAL TEMPS EARLY NEXT WEEK
* WARMING TREND WED INTO THU
FRI NIGHT...
MODELS IN AGREEMENT THAT STRONG LOW PRES WILL BE MOVING NE THROUGH
THE GT LAKES WITH WARM FRONT APPROACHING FROM THE S. WAA PRECIP
WILL BE OVERSPREADING SNE FRI EVENING AND CONTINUING THROUGH THE
NIGHT. SOUNDINGS AND PARTIAL THICKNESSES INDICATE ENOUGH COLD AIR
IN THE COLUMN TO SUPPORT A PERIOD OF SNOW THEN ICE IN THE DISTANT
INTERIOR BEFORE MILDER AIR GRADUALLY PUSHES NORTHWARD. DO NOT
EXPECT MUCH SNOW ACCUM AS MID LEVELS ARE WARMING QUICKLY...BUT AN
EXTENDED PERIOD OF FREEZING RAIN AND ICING IS POSSIBLE MAINLY N OF
I90 AND W OF I495 WHERE LOW LEVEL COLD AIR WILL BE SLOW TO SCOUR
OUT...AND WINTER WX ADVISORIES WILL LIKELY BE NEEDED. DO NOT EXPECT
SIGNIFICANT ICE ACCUM BUT UP TO A TENTH OF AN INCH OF ICE ACCRETION
IS POSSIBLE. EVEN ALONG THE COAST...THE RAIN MAY MIX WITH SLEET AT
THE ONSET. SLOWLY RISING TEMPS OVERNIGHT.
SATURDAY...
SHOWERS WILL CONTINUE INTO SAT AS WARM FRONT LIFTS NWD INTO
REGION...BUT FOCUS WILL GRADUALLY SHIFT TO THE COAST ASSOCD WITH
MODEST LOW LEVEL JET...THEN SHOWERS MOVE OFFSHORE DURING THE
AFTERNOON AS FRONT MOVES THROUGH. POPS WILL BE DECREASING FROM WEST
TO EAST DURING THE DAY. THERE IS STILL AN ELEVATED THUNDER
THREAT...MAINLY NEAR THE S COAST IN THE MORNING AS AREA OF SUBZERO
SWI AND MID 50S TT MOVE NWD. SFC INSTABILITY IS NIL AND LLJ IS NOT
AS ROBUST AND IS FURTHER OFFSHORE SO WIND THREAT IS MINIMAL. AS
WARM FRONT LIFTS NWD ACROSS THE COASTAL PLAIN...TEMPS WILL LIKELY
SPIKE WELL INTO THE 50S...ESPECIALLY RI AND SE MA...BUT TEMPS
PROBABLY HOLDING IN THE 40S N OF THE PIKE.
SUNDAY THROUGH TUESDAY...
MID LEVEL TROF WILL BE MOVING EAST INTO NEW ENG BRINGING A
NOTICEABLE COOLING TREND. STILL MILD SUNDAY...THEN COLDER WITH
BELOW NORMAL TEMPS MON AND TUE. IN FACT...MINS WILL LIKELY DROP
DOWN INTO THE SINGLE NUMBERS AND TEENS MON NIGHT. COASTAL STORMS
EXPECTED TO REMAIN OFFSHORE SUN AND MON...BUT SERIES OF SHORTWAVES
AND SFC TROFS MOVING INTO THE REGION MAY BRING A FEW RAIN/SNOW SUN
AND MON. MOSTLY SUNNY AND DRY WEATHER EXPECTED TUE AS SFC HIGH
BUILDS IN FROM THE WEST...BUT OCEAN EFFECT SNOW SHOWERS MAY AFFECT
THE OUTER CAPE.
WEDNESDAY AND THURSDAY...
GFS AND ECMWF INDICATE A SIGNIFICANT WARMING TREND AS HIGH PRES
MOVES S OF THE COAST WITH RETURN FLOW DEVELOPING. WED WILL BE THE
TRANSITION DAY AFTER A COLD START...THEN UNSEASONABLY MILD WEATHER
POSSIBLE BY THU AND ECMWF HAS THE POTENTIAL FOR TEMPS TO REACH THE
LOWER 60S. DID NOT GO QUITE THAT HIGH IN THE FORECAST AS THIS IS
STILL 7 DAYS AWAY.
&&
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT
MODERATE...30 PERCENT TO 60 PERCENT
HIGH...GREATER THAN 60 PERCENT
TONIGHT...
HIGH CONFIDENCE MVFR/IFR CONDITIONS IMPROVING GRADUALLY TO VFR BY
MORN /OVC 1-2 KFT CIGS LIFTING 3-5 KFT INTO MIDNIGHT/. VSBY
RESTRICTIONS WITH -SN/-RA ENDING W TO E AROUND MIDNIGHT /BEST CHCS
FOR IFR VSBYS WILL BE OVER THE ERN SHORELINE TERMINALS WITH GUSTY
NELY WINDS AROUND 20 KTS/.
FRIDAY...
HIGH CONFIDENCE VFR. LIGHT NELY FLOW VEERING OUT OF THE SE LATE AS
HIGH PRES SWEEPS ACROSS THE TERMINALS. LOW CIGS SHOULD DISSIPATE
BY MORN...WITH MID-HIGH LVL CLOUDS FILTERING THRU THE RGN IN
ADVANCE OF A DISTURBANCE FRI EVNG INTO SAT.
KBOS TERMINAL...
HIGH CONFIDENCE. IFR WITH -SN LASTING THE NEXT COUPLE OF HRS. FEEL
MOST OF THIS ENERGY AND LOWER CIGS WILL TRANSLATE OFFSHORE BY AS
LATE AS MIDNIGHT. THEREAFTER CONDITIONS IMPROVING MVFR TO VFR.
GUSTY NELY FLOWING DIMINISHING OVRNGT AS HIGH PRES BUILDS INTO THE
AREA...WINDS VEERING SELY BY TOMORROW AFTN WITH INCREASING MID-UPR
LVL CLOUDS. ENERGY FROM THE NEXT DISTURBANCE FRI NGT MAY BEGIN TO
IMPACT THE TERMINAL BY MIDNIGHT WITH -RAPL MIX WITH LOWER CIGS AND
REDUCED VSBYS TO MVFR.
OUTLOOK...FRIDAY NIGHT THROUGH TUESDAY...
FRIDAY NIGHT AND SATURDAY...
MODERATE CONFIDENCE. CONDITIONS DETERIORATING TO IFR DURING FRI
EVENING AS AREA OF PRECIP MOVES IN. PTYPE SNOW AND MIXED PRECIP IN
THE INTERIOR CHANGING TO RAIN...WITH MAINLY RAIN NEAR THE COAST.
SHOWERS AND IFR PERSISTING INTO SATURDAY...POSSIBLY IMPROVING TO
VFR LATE IN THE DAY. GUSTY S WINDS CAPE/ISLANDS LATE FRI NIGHT AND
SAT MORNING....BECOMING SW DURING THE AFTERNOON.
SATURDAY NIGHT THROUGH MONDAY...
MODERATE CONFIDENCE. MAINLY VFR...BUT A PERIOD OR TWO OF BRIEF
MVFR CONDITIONS ARE POSSIBLE ESPECIALLY NW ZONES.
TUESDAY...
HIGH CONFIDENCE. VFR...BUT OCEAN EFFECT CLOUDS AND A FEW SNOW
SHOWERS MAY BRING MVFR CONDITIONS TO THE OUTER CAPE.
&&
.MARINE...
TONIGHT...
WINDS HAVE STARTED TO DIMINISH ACROSS THE EASTERN COASTAL WATERS.
AS SUCH HAVE CONVERTED THE NEAR-SHORE GALE WARNINGS TO SMALL CRAFT
ADVISORIES. WILL CONTINUE TO MONITOR THE NEED TO EXTEND THE GALE
WARNINGS ACROSS THE EASTERN OUTER COASTAL WATERS. AT THIS
TIME...STILL THING WINDS WILL DIMINISH ENOUGH THOSE WARNINGS WILL
BE ABLE TO BE CONVERTED TO SMALL CRAFT ADVISORIES AS WELL.
ELSEWHERE...EXPECTING WIND GUSTS UP TO 30 KT OR SEAS TO REMAIN
ABOVE 5 FEET THE REST OF TONIGHT.
FRIDAY...
WINDS BELOW 25 KNOTS BUT SEAS REMAIN ABOVE 5 FEET ON ALL OUTER
WATERS. SMALL CRAFT ADVISORIES WILL BE NEEDED THROUGH THE DAY ON
THE AFFECTED WATERS.
OUTLOOK...FRIDAY NIGHT THROUGH MONDAY...
FRIDAY NIGHT AND SATURDAY...APPROACHING LOW LEVEL JET WILL BRING SCA
SOUTHERLY WIND GUSTS TO OPEN WATERS LATE FRI NIGHT AND SAT
MORNING...BUT PROBABLY REMAINING BELOW GALE AS STRONG LOW LEVEL
INVERSION WILL PREVENT STRONGER WINDS FROM MIXING DOWN. WINDS SHIFT
TO SW/W SAT AFTERNOON WITH GUSTS TO 25 KT.
SATURDAY NIGHT THROUGH TUESDAY...PERIODS OF SCA GUSTS EXPECTED
THROUGH THE PERIOD. MAINLY WEST WINDS SAT NIGHT INTO MON...SHIFTING
TO N/NW BY TUE.
&&
.CLIMATE...
A PUBLIC INFORMATION STATEMENT WAS ISSUED AT 225 PM. THIS
STATEMENT GIVES A REVIEW OF DECEMBER-JANUARY-FEBRUARY CONDITIONS AT
OUR FOUR CLIMATE SITES...BOSTON-PROVIDENCE-HARTFORD-WORCESTER.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 10 AM EST FRIDAY FOR ANZ232-235-237.
SMALL CRAFT ADVISORY UNTIL 4 AM EST FRIDAY FOR ANZ233-234.
SMALL CRAFT ADVISORY UNTIL 2 AM EST FRIDAY FOR ANZ230-236.
SMALL CRAFT ADVISORY UNTIL NOON EST FRIDAY FOR ANZ231-251.
GALE WARNING UNTIL 2 AM EST FRIDAY FOR ANZ250-254.
SMALL CRAFT ADVISORY UNTIL 6 AM EST SATURDAY FOR ANZ255-256.
&&
$$
SYNOPSIS...WTB/KJC
NEAR TERM...BELK/WTB
SHORT TERM...WTB
LONG TERM...KJC
AVIATION...BELK/KJC/SIPPRELL
MARINE...BELK/WTB/KJC
CLIMATE...STAFF
AREA FORECAST DISCUSSION
NWS TAUNTON MA
614 PM EST THU MAR 1 2012
.SYNOPSIS...
LOW PRESSURE RACING ACROSS NEW ENGLAND WILL MOVE OFF TO THE EAST
TONIGHT. HIGH PRESSURE WILL BRING DRY WEATHER OVERNIGHT AND
FRIDAY. STRONG LOW PRESSURE WILL MOVE THROUGH THE GREAT LAKES LATE
FRIDAY INTO FRIDAY NIGHT AND SWING A COLD FRONT THROUGH NEW
ENGLAND SATURDAY. MAINLY DRY AND COLDER WEATHER WILL FOLLOW EARLY
NEXT WEEK...THEN A SIGNIFICANT WARMING TREND IS POSSIBLE TOWARD
MIDDLE AND END OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
LIGHT SNOW ALONG AND NORTH OF THE MASS PIKE WITH VSBYS BELOW 1
MILE IN THE MERRIMACK VALLEY AND PARTS OF THE BOSTON METROWEST.
FARTHER SOUTH LIGHT MIXED RAIN/SNOW ACROSS CT-RI-SOUTHEAST MASS.
RADAR SHOWS THIS PCPN AREA EXTENDS WEST TO CENTRAL NY...SO IT
SHOULD TAKE SEVERAL HOURS FOR THE PCPN TO DIMINISH.
NORTHEAST WINDS LINGERED THROUGH EVENING IN EASTERN MASSACHUSETTS
BUT THE TREND SHOULD BE TOWARD A NORTH WIND ALL AREAS TONIGHT.
THIS WILL DRAW COLDER AIR IN AND SHOULD CONTRIBUTE TO CHANGING
PCPN OVER TO SNOW BEFORE IT ENDS.
UPPER SHORTWAVE OVER NY IS SUPPORTING THIS PCPN. THE SHORTWAVE
WILL CROSS NEW ENGLAND A FEW HOURS EITHER SIDE OF 00Z. ONCE IT
MOVES PAST...PCPN SHOULD TAPER OFF. WE HAVE MAINTAINED LIKELY TO
CATEGORICAL POPS ACROSS SRN NH/MUCH OF MASS/NORTHERN CT/NORTHERN
RI THIS EVENING WITH POPS THEN DIMINISHING OVERNIGHT.
TEMPS/DEWPOINTS ARE A BLEND OF HRRR AND MOS.
WITH ONGOING PCPN AND A FEW HEAVIER SPOTS ON RADAR...WE ARE
MAINTAINING EXISTING WINTER WEATHER HEADLINES THROUGH THE EVENING
RUSH HOUR. BUT WE EXPECT THEY WILL EITHER EXPIRE OR BE EXTENDED
FOR JUST A COUPLE OF ADDITIONAL HOURS.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH 6 PM FRIDAY/...
HIGH PRESSURE OVER THE MIDWEST MOVES OVER NEW ENGLAND FRIDAY
MORNING. WE EXPECT PARTIAL CLEARING...BUT LINGERING MOISTURE BELOW
850 MB SUGGESTS PARTLY TO MOSTLY CLOUDY SKIES DURING THE DAY.
MEANWHILE...INCREASING MOISTURE AT HIGH LEVELS IN THE WARM
ADVECTION AHEAD OF THE NEXT SYSTEM. SO EXPECT INCREASING HIGH
CLOUDS OVER THE TOP OF ANY LOW CLOUDS.
925 MB TEMPS OF -2C TO -4C SUPPORT MAX TEMPS IN THE MID 30S TO
AROUND 40. A BLEND OF MOS ACHIEVED THIS RANGE.
&&
.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
HIGHLIGHTS...
* MIXED PRECIP AND ICE INTERIOR FRI NIGHT CHANGING TO RAIN.
* MILD WITH SHOWERS FOR SATURDAY
* MUCH COLDER WITH BELOW NORMAL TEMPS EARLY NEXT WEEK
* WARMING TREND WED INTO THU
FRI NIGHT...
MODELS IN AGREEMENT THAT STRONG LOW PRES WILL BE MOVING NE THROUGH
THE GT LAKES WITH WARM FRONT APPROACHING FROM THE S. WAA PRECIP
WILL BE OVERSPREADING SNE FRI EVENING AND CONTINUING THROUGH THE
NIGHT. SOUNDINGS AND PARTIAL THICKNESSES INDICATE ENOUGH COLD AIR
IN THE COLUMN TO SUPPORT A PERIOD OF SNOW THEN ICE IN THE DISTANT
INTERIOR BEFORE MILDER AIR GRADUALLY PUSHES NORTHWARD. DO NOT
EXPECT MUCH SNOW ACCUM AS MID LEVELS ARE WARMING QUICKLY...BUT AN
EXTENDED PERIOD OF FREEZING RAIN AND ICING IS POSSIBLE MAINLY N OF
I90 AND W OF I495 WHERE LOW LEVEL COLD AIR WILL BE SLOW TO SCOUR
OUT...AND WINTER WX ADVISORIES WILL LIKELY BE NEEDED. DO NOT EXPECT
SIGNIFICANT ICE ACCUM BUT UP TO A TENTH OF AN INCH OF ICE ACCRETION
IS POSSIBLE. EVEN ALONG THE COAST...THE RAIN MAY MIX WITH SLEET AT
THE ONSET. SLOWLY RISING TEMPS OVERNIGHT.
SATURDAY...
SHOWERS WILL CONTINUE INTO SAT AS WARM FRONT LIFTS NWD INTO
REGION...BUT FOCUS WILL GRADUALLY SHIFT TO THE COAST ASSOCD WITH
MODEST LOW LEVEL JET...THEN SHOWERS MOVE OFFSHORE DURING THE
AFTERNOON AS FRONT MOVES THROUGH. POPS WILL BE DECREASING FROM WEST
TO EAST DURING THE DAY. THERE IS STILL AN ELEVATED THUNDER
THREAT...MAINLY NEAR THE S COAST IN THE MORNING AS AREA OF SUBZERO
SWI AND MID 50S TT MOVE NWD. SFC INSTABILITY IS NIL AND LLJ IS NOT
AS ROBUST AND IS FURTHER OFFSHORE SO WIND THREAT IS MINIMAL. AS
WARM FRONT LIFTS NWD ACROSS THE COASTAL PLAIN...TEMPS WILL LIKELY
SPIKE WELL INTO THE 50S...ESPECIALLY RI AND SE MA...BUT TEMPS
PROBABLY HOLDING IN THE 40S N OF THE PIKE.
SUNDAY THROUGH TUESDAY...
MID LEVEL TROF WILL BE MOVING EAST INTO NEW ENG BRINGING A
NOTICEABLE COOLING TREND. STILL MILD SUNDAY...THEN COLDER WITH
BELOW NORMAL TEMPS MON AND TUE. IN FACT...MINS WILL LIKELY DROP
DOWN INTO THE SINGLE NUMBERS AND TEENS MON NIGHT. COASTAL STORMS
EXPECTED TO REMAIN OFFSHORE SUN AND MON...BUT SERIES OF SHORTWAVES
AND SFC TROFS MOVING INTO THE REGION MAY BRING A FEW RAIN/SNOW SUN
AND MON. MOSTLY SUNNY AND DRY WEATHER EXPECTED TUE AS SFC HIGH
BUILDS IN FROM THE WEST...BUT OCEAN EFFECT SNOW SHOWERS MAY AFFECT
THE OUTER CAPE.
WEDNESDAY AND THURSDAY...
GFS AND ECMWF INDICATE A SIGNIFICANT WARMING TREND AS HIGH PRES
MOVES S OF THE COAST WITH RETURN FLOW DEVELOPING. WED WILL BE THE
TRANSITION DAY AFTER A COLD START...THEN UNSEASONABLY MILD WEATHER
POSSIBLE BY THU AND ECMWF HAS THE POTENTIAL FOR TEMPS TO REACH THE
LOWER 60S. DID NOT GO QUITE THAT HIGH IN THE FORECAST AS THIS IS
STILL 7 DAYS AWAY.
&&
.AVIATION /23Z THURSDAY THROUGH TUESDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT
MODERATE...30 PERCENT TO 60 PERCENT
HIGH...GREATER THAN 60 PERCENT
TONIGHT...
HIGH CONFIDENCE MVFR/IFR CONDITIONS IMPROVING GRADUALLY TO VFR BY
MORN /OVC 1-2 KFT CIGS LIFTING 3-5 KFT INTO MIDNIGHT/. VSBY
RESTRICTIONS WITH -SN/-RA ENDING W TO E AROUND MIDNIGHT /BEST CHCS
FOR IFR VSBYS WILL BE OVER THE ERN SHORELINE TERMINALS WITH GUSTY
NELY WINDS AROUND 20 KTS/.
FRIDAY...
HIGH CONFIDENCE VFR. LIGHT NELY FLOW VEERING OUT OF THE SE LATE AS
HIGH PRES SWEEPS ACROSS THE TERMINALS. LOW CIGS SHOULD DISSIPATE
BY MORN...WITH MID-HIGH LVL CLOUDS FILTERING THRU THE RGN IN
ADVANCE OF A DISTURBANCE FRI EVNG INTO SAT.
KBOS TERMINAL...
HIGH CONFIDENCE. IFR WITH -SN LASTING THE NEXT COUPLE OF HRS. FEEL
MOST OF THIS ENERGY AND LOWER CIGS WILL TRANSLATE OFFSHORE BY AS
LATE AS MIDNIGHT. THEREAFTER CONDITIONS IMPROVING MVFR TO VFR.
GUSTY NELY FLOWING DIMINISHING OVRNGT AS HIGH PRES BUILDS INTO THE
AREA...WINDS VEERING SELY BY TOMORROW AFTN WITH INCREASING MID-UPR
LVL CLOUDS. ENERGY FROM THE NEXT DISTURBANCE FRI NGT MAY BEGIN TO
IMPACT THE TERMINAL BY MIDNIGHT WITH -RAPL MIX WITH LOWER CIGS AND
REDUCED VSBYS TO MVFR.
OUTLOOK...FRIDAY NIGHT THROUGH TUESDAY...
FRIDAY NIGHT AND SATURDAY...
MODERATE CONFIDENCE. CONDITIONS DETERIORATING TO IFR DURING FRI
EVENING AS AREA OF PRECIP MOVES IN. PTYPE SNOW AND MIXED PRECIP IN
THE INTERIOR CHANGING TO RAIN...WITH MAINLY RAIN NEAR THE COAST.
SHOWERS AND IFR PERSISTING INTO SATURDAY...POSSIBLY IMPROVING TO
VFR LATE IN THE DAY. GUSTY S WINDS CAPE/ISLANDS LATE FRI NIGHT AND
SAT MORNING....BECOMING SW DURING THE AFTERNOON.
SATURDAY NIGHT THROUGH MONDAY...
MODERATE CONFIDENCE. MAINLY VFR...BUT A PERIOD OR TWO OF BRIEF
MVFR CONDITIONS ARE POSSIBLE ESPECIALLY NW ZONES.
TUESDAY...
HIGH CONFIDENCE. VFR...BUT OCEAN EFFECT CLOUDS AND A FEW SNOW
SHOWERS MAY BRING MVFR CONDITIONS TO THE OUTER CAPE.
&&
.MARINE...
TONIGHT...
CONTINUED NORTH-NORTHEAST GALES ON THE EASTERN WATERS THIS
EVENING BASED ON OBSERVED BUOY WINDS. WINDS SHOULD DIMINISH
OVERNIGHT...BUT SEAS WILL LINGER ABOVE 5 FEET ON ALL OUTER WATERS.
SMALL CRAFT ADVISORIES WILL COVER ALL ZONES NOT IN A GALE WARNING.
TIDAL RESIDUALS ARE RUNNING AROUND 2.25 FEET HIGH. BUT THE
ASTRONOMICAL TIDES ARE NOT HIGH. SO NO COASTAL FLOODING IS
EXPECTED.
FRIDAY...
WINDS BELOW 25 KNOTS BUT SEAS REMAIN ABOVE 5 FEET ON ALL OUTER
WATERS. SMALL CRAFT ADVISORIES WILL BE NEEDED THROUGH THE DAY ON
THE AFFECTED WATERS.
OUTLOOK...FRIDAY NIGHT THROUGH MONDAY...
FRIDAY NIGHT AND SATURDAY...APPROACHING LOW LEVEL JET WILL BRING SCA
SOUTHERLY WIND GUSTS TO OPEN WATERS LATE FRI NIGHT AND SAT
MORNING...BUT PROBABLY REMAINING BELOW GALE AS STRONG LOW LEVEL
INVERSION WILL PREVENT STRONGER WINDS FROM MIXING DOWN. WINDS SHIFT
TO SW/W SAT AFTERNOON WITH GUSTS TO 25 KT.
SATURDAY NIGHT THROUGH TUESDAY...PERIODS OF SCA GUSTS EXPECTED
THROUGH THE PERIOD. MAINLY WEST WINDS SAT NIGHT INTO MON...SHIFTING
TO N/NW BY TUE.
&&
.CLIMATE...
A PUBLIC INFORMATION STATEMENT WAS ISSUED AT 225 PM. THIS
STATEMENT GIVES A REVIEW OF DECEMBER-JANUARY-FEBRUARY CONDITIONS AT
OUR FOUR CLIMATE SITES...BOSTON-PROVIDENCE-HARTFORD-WORCESTER.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 10 AM EST FRIDAY FOR ANZ232-235-237.
SMALL CRAFT ADVISORY UNTIL 4 AM EST FRIDAY FOR ANZ233-234.
SMALL CRAFT ADVISORY UNTIL 2 AM EST FRIDAY FOR ANZ230-236.
GALE WARNING UNTIL 2 AM EST FRIDAY FOR ANZ231-250-251-254.
SMALL CRAFT ADVISORY UNTIL 6 AM EST SATURDAY FOR ANZ255-256.
&&
$$
SYNOPSIS...WTB/KJC
NEAR TERM...WTB/KJC
SHORT TERM...WTB
LONG TERM...KJC
AVIATION...WTB/SIPPRELL
MARINE...WTB/KJC
CLIMATE...WFO BOX
AREA FORECAST DISCUSSION
NWS TAUNTON MA
455 PM EST WED FEB 29 2012
.SYNOPSIS...
A SERIES OF LOW PRESSURE SYSTEMS PASSING NEAR AND SOUTH OF THE
REGION WILL BRING PERIODS OF ACCUMULATING SNOW AND MIXED
PRECIPITATION INTO THURSDAY. FAST MOVING HIGH PRESSURE WILL BRING
DRY WEATHER ON FRIDAY. LOW PRESSURE WILL PASS WELL WEST OF THE
REGION...RESULTING IN RAINY AND MILD WEATHER WITH BLUSTERY WINDS
SATURDAY. COOLER...DRY WEATHER WILL FOLLOW EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
AREA OF MODERATE TO OCCASIONALLY HEAVY SNOW MOVING ACROSS SNE THIS
AFTERNOON WILL LIKELY BRING 2-4" OVER MUCH OF THE INTERIOR THROUGH
00Z. HRRR REFLECTIVITY DOING A PRETTY GOOD JOB WITH CURRENT AREA
OF PRECIP AND CONFINES HEAVIEST SNOWFALL MOSTLY ALONG AND S OF THE
MASS PIKE THROUGH 00Z.
THIS AREA OF SNOWFALL IS ASSOCD WITH THE INITIAL SURGE OF
ISENTROPIC LIFT WHICH WILL BE EXITING EARLY THIS EVENING AS PSEUDO
DRY SLOT TEMPORARILY MOVES IN. THIS WILL RESULT IN PRECIP
INTENSITY DIMINISHING FOR A TIME THIS EVENING. ALSO...MID LEVEL
WARMING MOVING UP FROM THE SW WILL RESULT IN A CHANGEOVER TO
SLEET/FZRA IN THE INTERIOR MAINLY S OF THE PIKE AND TO MAINLY
RAIN ALONG THE S COAST THROUGH THIS EVENING.
NEXT PULSE OF PRECIP MOVES IN FROM THE SW AFTER 06Z AS SFC WAVE
TRACKS S OF NEW ENGLAND. DEVELOPING EASTERLY LLJ ENHANCES THE LOW
LEVEL CONVERGENCE AND INCREASES OMEGA. WE DISCOUNTED THE WARMER
GFS SOLUTION WHICH HAS STRUGGLED WITH THE THERMAL PROFILE...SO
USED NAM/ECMWF BLEND FOR THIS FORECAST.
PTYPE WITH THIS NEXT BATCH OF PRECIP SHOULD BE PRIMARILY SNOW N
OF THE PIKE WITH SOME MIXING WITH SLEET AT TIMES NEAR THE
PIKE...AND COULD MIX WITH RAIN ALONG IMMEDIATE E MA COASTLINE
INCLUDING BOS. THE MORNING COMMUTE WILL LIKELY BE A PROBLEM N OF
THE PIKE. SOUTH OF THE PIKE...WE ARE LOOKING AT MOSTLY A
RAIN/SNOW/SLEET MIXTURE WITH MAINLY RAIN NEAR THE S COAST.
GUSTY E WINDS DEVELOPING ALONG THE COAST...ESPECIALLY
CAPE/ISLANDS.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/...
EXPECT PERIODS OF SNOW OR MIXED PRECIP TO CONTINUE FOR MUCH OF
THURSDAY AS COASTAL LOW SLOWLY MEANDERS S OF ACK FOR MUCH OF THE
DAY. PERSISTENT ELY LOW LEVEL JET WILL FOCUS THE STEADIEST
SNOWFALL ACROSS N ZONES AND PARTICULARLY ACROSS NE MA AND THE
MERRIMACK VALLEY WHERE A PERIOD OF HEAVY SNOW IS POSSIBLE. AS A
RESULT WE EXPANDED THE WINTER STORM WARNING EASTWARD TO INCLUDE
BOS NORTHWARD ALONG COASTAL ESSEX COUNTY.
SOUTH OF THE MASS PIKE...THE PRECIP IS EXPECTED TO BE LIGHTER BUT
THE COLUMN WILL ALSO BE COOLING DURING THE DAY AS THE WINDS BACK.
SO WE EXPECT ANY RAIN OR MIXED PRECIP TO EVENTUALLY CHANGE BACK
TO SNOW BEFORE ENDING. ADDITIONAL MINOR ACCUM IS POSSIBLE AWAY
FROM THE S COAST. IN ADDITION...GUSTY E/NE WINDS WILL CONTINUE
OVER THE CAPE/ISLANDS AND E COASTAL MA.
THIS IS A DIFFICULT SNOWFALL FORECAST DUE TO THE UNCERTAINTY IN
THE NORTHWARD EXTENT OF MID LEVEL WARMING AND HOW MUCH ENHANCEMENT
OCCURS WITH LOW LEVEL JET. OUR CURRENT FORECAST IS FOR 8-12"
NORTH OF THE PIKE AND 4-8" FROM BOS NWD ALONG COASTAL ESSEX
COUNTY. 2-6" N OF HFD-PVD-TAN TO THE MASS PIKE AND A COATING TO
2" ALONG THE S COAST.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
OVERVIEW AND MODEL PREFERENCE...
MEDIUM RANGE MODEL SUITE IN PRETTY GOOD AGREEMENT INTO THIS
WEEKEND...THEN SOME DIVERGENCE SEEN BEYOND SUNDAY NAMELY WITH A
POSSIBLE WEAK LOW THAT MAY PASS S OF NEW ENGLAND SUNDAY NIGHT OR
MONDAY TIMEFRAME WITH ANOTHER QUICK BATCH OF LIGHT PRECIP. OVERALL
THOUGH...LOOKS LIKE MOST OP MODELS SHOWING GENERAL AGREEMENT
AND...BETTER STILL AGREEMENT WITH MOST OF THEIR COMPANION ENSEMBLE
MEANS INTO EARLY NEXT WEEK WITH THE SETUP OF RIDGING ALONG THE
EASTERN SEABOARD.
THURSDAY NIGHT...UPPER LEVEL LOW AND ITS SURFACE REFLECTION
WEAKENS AS THEY WORK ACROSS NORTHERN NEW ENGLAND WITH SOME SURFACE
RIDGING BUILDING DOWN THE COAST. MAY SEE LEFTOVER PRECIP LINGER
ALONG THE E COAST WITH ONSHORE FLOW. OTHERWISE...SHOULD SEE
GENERAL IMPROVEMENT OVERNIGHT.
FRIDAY-FRIDAY NIGHT...WEAK HIGH PRES WILL MOVE ACROSS THE REGION
DURING THE DAY. WILL PROBABLY SEE SOME BREAKS IN THE CLOUDS...
THOUGH NEXT SYSTEM QUICKLY WORKING E SO ANY BREAKS WILL BE SHORT
LIVED. WINDS WILL VEER AROUND TO S AND START TO PICK UP ESPECIALLY
FRI NIGHT AS PRECIP APPROACHES. TEMPS WILL HIT THEIR LOWS EARLY
FRI NIGHT...THEN WILL RISE THROUGH THE NIGHT AS PRECIP MOVES IN.
TEMPS MAY BE COLD ENOUGH FOR PRECIP TO START AS MIXED SLEET OR
FREEZING RAIN. HOWEVER...AS S WINDS INCREASES...MILDER AIR WILL
WORK IN AND MOST AREAS SHOULD CHANGE OVER TO RAIN BEFORE SUNRISE.
SATURDAY...MODELS STILL IN VERY GOOD AGREEMENT IN SWINGING A COLD
FRONT TOWARD THE REGION AS ITS ASSOCIATED STRONG LOW PRES MOVES
ACROSS EASTERN ONTARIO AND CENTRAL QUEBEC. VERY STRONG H925 JET
WORKS ACROSS INTO EASTERN MA/RI BY AROUND MIDDAY THROUGH THE
AFTERNOON...UPWARDS TO 65-70 KT. WILL LIKELY SEE WIND GUSTS
INCREASE QUICKLY WITH GUSTS UP TO 25-35 KT...HIGHEST ALONG THE S
COAST AND ISLANDS. SOME OF THE MOS GUIDANCE STARTING TO SHOW MILD
TEMPS ALONG WITH 2M MODEL TEMPS...SO USED THESE FOR MAX READINGS
OF THE LOWER-MID 50S FOR MOST AREAS.
ALSO NOTING GOOD AREA OF INSTABILITY WORKING IN AHEAD OF THE
FRONT...WITH LIFTED INDICES FROM ZERO TO -2...K INDICES IN THE
LOWER 30S AND TOTAL TOTALS IN THE LOWER 50S...AGAIN ACROSS EASTERN
AREAS. HAVE MENTIONED CHANCE OF TSTMS FOR THE LATE MORNING AND
AFTERNOON ACROSS THESE AREAS. WILL NEED TO MONITOR FOR STRONG
GUSTS THAT MAY MIX DOWN WITH ANY CONVECTION.
SATURDAY NIGHT THROUGH MONDAY NIGHT...LOW CONFIDENCE. THE SHOWERS
SHOULD HAVE PRETTY MUCH EXITED THE SOUTHEAST NEW ENGLAND COAST BY
EARLY SAT EVENING...AS THE COLD FRONT WORKS THROUGH THE REGION.
HOWEVER...WE ARE GOING TO HAVE TO WATCH A COUPLE WAVES OF LOW
PRESSURE THAT FORM ON THE FRONT...WHICH WILL BE HUNG UP OFF THE
ATLANTIC COAST. THE LATEST GFS/ECMWF KEEP BOTH WAVES OF
LOW PRESSURE FAR ENOUGH SOUTHEAST OF THE REGION TO KEEP MOST OF THE
PRECIPITATION OFF THE SOUTHEAST NEW ENGLAND COAST. HOWEVER...A FEW
OF THE GFS ENSEMBLES AND THE LATEST GGEM SHOW THE POTENTIAL FOR A
TRACK CLOSER TO THE COAST. LOW CONFIDENCE AT THIS TIME...BUT DID
INCLUDE SOME LOW POPS TO COVER THIS POTENTIAL. IF PRECIPITATION
DOES MAKE IT FAR ENOUGH WEST...IT MAY BE COLD ENOUGH TO SUPPORT SOME
WINTRY PRECIPITATION. ITS A LOW PROBABILITY AT THIS POINT...BUT
CERTAINLY WILL NEED TO BE WATCHED.
TUESDAY AND WEDNESDAY...MODERATE TO HIGH CONFIDENCE.
IT SHOULD START OFF QUITE COLD TUE MORNING WITH HIGH PRESSURE
OVERHEAD. HOWEVER...TEMPERATURES SHOULD MODERATE SIGNIFICANTLY BY
WED AS THE HIGH MOVES OFF THE COAST WITH A RETURN SOUTHWEST FLOW OF
AIR. EXPECT DRY WEATHER OVER THIS PERIOD.
&&
.AVIATION /21Z WEDNESDAY THROUGH MONDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT
MODERATE...30 PERCENT TO 60 PERCENT
HIGH...GREATER THAN 60 PERCENT
THROUGH 00Z...CONDITIONS LOWERING TO IFR/LIFR IN SNOW WITH RAIN
ALONG THE IMMEDIATE S COAST.
TONIGHT...HIGH CONFIDENCE. WIDESPREAD IFR/LIFR IN SNOW NORTH...
WITH SNOW CHANGING TO MIXED PRECIP/RAIN SOUTH. DRY SLOT MAY
RESULT IN A BRIEF LULL IN THE PRECIP THIS EVENING...BUT ANOTHER
PULSE OF SNOW/MIXED PRECIP EXPECTED AFTER 06Z. EASTERLY WIND GUSTS
TO 30 KT DEVELOPING ACROSS CAPE/ISLANDS AND SE MA.
THURSDAY...MODERATE TO HIGH CONFIDENCE. IFR/LIFR CONDITIONS
AS AREAS OF SNOW NORTH AND MIXED PRECIP/RAIN NEAR THE S COAST
CONTINUE. STEADIEST PRECIP SHOULD BE CONFINED ALONG AND N OF THE
MASS PIKE. E WIND GUSTS TO 30-35 KT POSSIBLE OVER THE OUTER CAPE
AND ACK.
KBOS TERMINAL...HIGH CONFIDENCE IN TAF. EXPECT IFR CONDITIONS TO
PERSIST FOR MUCH OF THE PERIOD. PTYPE MOSTLY SNOW BUT COULD MIX
WITH SLEET OR RAIN AT TIMES TONIGHT.
OUTLOOK...THURSDAY NIGHT THROUGH MONDAY...
THURSDAY NIGHT...MODERATE CONFIDENCE. LEFTOVER PERIODS OF MVFR-IFR
CIGS/VSBYS MAINLY ACROSS EASTERN MA/RI/S NH. MVFR VSBYS MAY LINGER
AFTER MIDNIGHT ALONG E COAST...OTHERWISE MAINLY VFR CONDITIONS
AFTER MIDNIGHT.
FRIDAY...MODERATE CONFIDENCE. MAINLY VFR CONDITIONS THROUGH THE
DAY...THEN WILL LIKELY SEE MVFR CIGS/VSBYS MOVE IN FROM W-E MAINLY
AROUND OR AFTER MIDNIGHT IN MAINLY RAIN...THOUGH MIXED FZRA/PL
ACROSS INLAND AREAS AT THE ONSET. PATCHY FOG DEVELOPING LATE.
SATURDAY...MODERATE CONFIDENCE. PERIODS OF MVFR-IFR CONDITIONS
LIKELY IN RAIN. PATCHY FOG EARLY. PRECIP CHANGING OVER TO SNOW SAT
NIGHT BUT WILL TAPER OFF FROM W-E. S WIND GUSTS WILL LIKELY REACH
25-35 KT ACROSS E MA/RI...HIGHEST ACROSS S COAST AND THE ISLANDS.
SATURDAY NIGHT THROUGH MONDAY...MODERATE CONFIDENCE. PROBABLY VFR
THE MAJORITY OF THE TIME...BUT A PERIOD OR TWO OF MVFR CONDITIONS
ARE POSSIBLE.
&&
.MARINE...
EXPECT A PERIOD OF GALE FORCE EASTERLY WINDS TONIGHT...MAINLY
OUTER WATERS AS LLJ MOVES INTO THE WATERS. FOCUS FOR GALE FORCE
WINDS ON THU WILL SHIFT TO THE EAST COASTAL MA WATERS...ESPECIALLY
EAST OF CAPE COD TO EAST OF CAPE ANN. SEAS WILL BUILD TO 17 FT
OVER THE EASTERN OUTER WATERS ON THU.
FORTUNATELY THE ASTRONOMICAL TIDES ARE VERY LOW AND SO COASTAL
FLOODING IS NOT ANTICIPATED.
OUTLOOK...THURSDAY NIGHT THROUGH MONDAY...
THURSDAY NIGHT...WINDS WILL BACK FROM NE TO N AND SLOWLY DIMINISH.
SEAS WILL ALSO SLOWLY SUBSIDE...BUT REMAIN WELL ABOVE 5 FT ON MOST
OF THE WATERS...HIGHEST ON THE EASTERN OUTER WATERS.
FRIDAY...NE WINDS GUSTING UP TO 30 KT EARLY WILL DIMINISH DURING
THE AFTERNOON...THEN VEER TO SE-S FRI NIGHT AS NEXT SYSTEM
APPROACHES. SEAS WILL REMAIN AOA 5 FT ON THE OPEN WATERS.
SATURDAY...STRONG LOW LEVEL JET WILL MOVE ACROSS THE WATERS AHEAD
OF APPROACHING COLD FRONT. EXPECT S-SW WINDS TO GUSTING UP TO GALE
FORCE OVER THE OPEN WATERS SAT AFTERNOON. SEAS WILL BUILD UP TO
10-12 FT...HIGHEST ON THE SOUTHERN OUTER WATERS.
SATURDAY NIGHT THROUGH MONDAY...MAY SEE LEFTOVER GALE FORCE GUSTS
EARLY SAT NIGHT ON THE EASTERN OUTER WATERS. OTHERWISE...ENOUGH
COLD AIR ADVECTION SHOULD RESULT IN SCA NORTHWEST WIND GUSTS AND
SEAS ACROSS THE OUTER WATERS FOR A GOOD PORTION OF THE PERIOD.
THERE COULD BE A PERIOD WHERE THE WINDS TURN MORE NORTH NORTHEAST
IF AN OCEAN STORM TRACKS CLOSE ENOUGH TO THE COAST.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...WINTER WEATHER ADVISORY UNTIL 6 AM EST THURSDAY FOR CTZ002>004.
MA...WINTER STORM WARNING UNTIL 6 PM EST THURSDAY FOR MAZ002>010-
012-014-015-026.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR MAZ017-
018.
WINTER WEATHER ADVISORY UNTIL 6 PM EST THURSDAY FOR MAZ013-016.
WINTER WEATHER ADVISORY UNTIL 6 AM EST THURSDAY FOR MAZ011.
NH...WINTER STORM WARNING UNTIL 6 PM EST THURSDAY FOR NHZ011-012-
015.
RI...WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR RIZ002-
004-005.
WINTER WEATHER ADVISORY UNTIL 6 AM EST THURSDAY FOR RIZ001-003.
MARINE...GALE WARNING FROM 1 AM TO 4 PM EST THURSDAY FOR ANZ232-255.
SMALL CRAFT ADVISORY UNTIL 2 AM EST FRIDAY FOR ANZ233>237.
SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 2 AM EST
FRIDAY FOR ANZ230.
GALE WARNING FROM 5 AM THURSDAY TO 2 AM EST FRIDAY FOR ANZ231-
251.
GALE WARNING FROM 1 AM THURSDAY TO 2 AM EST FRIDAY FOR ANZ250-
254.
GALE WARNING UNTIL 3 AM EST THURSDAY FOR ANZ256.
&&
$$
SYNOPSIS...KJC/FRANK
NEAR TERM...KJC
SHORT TERM...KJC
LONG TERM...FRANK/EVT
AVIATION...KJC/FRANK/EVT
MARINE...KJC/FRANK/EVT
AREA FORECAST DISCUSSION
NWS TAUNTON MA
401 PM EST WED FEB 29 2012
.SYNOPSIS...
A SERIES OF LOW PRESSURE SYSTEMS PASSING NEAR AND SOUTH OF THE
REGION WILL BRING PERIODS OF ACCUMULATING SNOW AND MIXED
PRECIPITATION INTO THURSDAY. FAST MOVING HIGH PRESSURE WILL BRING
DRY WEATHER ON FRIDAY. LOW PRESSURE PASSING WELL WEST OF THE
REGION WILL RESULT IN RAINY AND MILD WEATHER WITH BLUSTERY WINDS
SATURDAY...FOLLOWED BY CHILLIER WEATHER EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
AREA OF MODERATE TO OCCASIONALLY HEAVY SNOW MOVING ACROSS SNE THIS
AFTERNOON WILL LIKELY BRING 2-4" OVER MUCH OF THE INTERIOR THROUGH
00Z. HRRR REFLECTIVITY DOING A PRETTY GOOD JOB WITH CURRENT AREA
OF PRECIP AND CONFINES HEAVIEST SNOWFALL MOSTLY ALONG AND S OF THE
MASS PIKE THROUGH 00Z.
THIS AREA OF SNOWFALL IS ASSOCD WITH THE INITIAL SURGE OF
ISENTROPIC LIFT WHICH WILL BE EXITING EARLY THIS EVENING AS PSEUDO
DRY SLOT TEMPORARILY MOVES IN. THIS WILL RESULT IN PRECIP
INTENSITY DIMINISHING FOR A TIME THIS EVENING. ALSO...MID LEVEL
WARMING MOVING UP FROM THE SW WILL RESULT IN A CHANGEOVER TO
SLEET/FZRA IN THE INTERIOR MAINLY S OF THE PIKE AND TO MAINLY
RAIN ALONG THE S COAST THROUGH THIS EVENING.
NEXT PULSE OF PRECIP MOVES IN FROM THE SW AFTER 06Z AS SFC WAVE
TRACKS S OF NEW ENGLAND. DEVELOPING EASTERLY LLJ ENHANCES THE LOW
LEVEL CONVERGENCE AND INCREASES OMEGA. WE DISCOUNTED THE WARMER
GFS SOLUTION WHICH HAS STRUGGLED WITH THE THERMAL PROFILE...SO
USED NAM/ECMWF BLEND FOR THIS FORECAST.
PTYPE WITH THIS NEXT BATCH OF PRECIP SHOULD BE PRIMARILY SNOW N
OF THE PIKE WITH SOME MIXING WITH SLEET AT TIMES NEAR THE
PIKE...AND COULD MIX WITH RAIN ALONG IMMEDIATE E MA COASTLINE
INCLUDING BOS. THE MORNING COMMUTE WILL LIKELY BE A PROBLEM N OF
THE PIKE. SOUTH OF THE PIKE...WE ARE LOOKING AT MOSTLY A
RAIN/SNOW/SLEET MIXTURE WITH MAINLY RAIN NEAR THE S COAST.
GUSTY E WINDS DEVELOPING ALONG THE COAST...ESPECIALLY
CAPE/ISLANDS.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/...
EXPECT PERIODS OF SNOW OR MIXED PRECIP TO CONTINUE FOR MUCH OF
THURSDAY AS COASTAL LOW SLOWLY MEANDERS S OF ACK FOR MUCH OF THE
DAY. PERSISTENT ELY LOW LEVEL JET WILL FOCUS THE STEADIEST
SNOWFALL ACROSS N ZONES AND PARTICULARLY ACROSS NE MA AND THE
MERRIMACK VALLEY WHERE A PERIOD OF HEAVY SNOW IS POSSIBLE. AS A
RESULT WE EXPANDED THE WINTER STORM WARNING EASTWARD TO INCLUDE
BOS NORTHWARD ALONG COASTAL ESSEX COUNTY.
SOUTH OF THE MASS PIKE...THE PRECIP IS EXPECTED TO BE LIGHTER BUT
THE COLUMN WILL ALSO BE COOLING DURING THE DAY AS THE WINDS BACK.
SO WE EXPECT ANY RAIN OR MIXED PRECIP TO EVENTUALLY CHANGE BACK
TO SNOW BEFORE ENDING. ADDITIONAL MINOR ACCUM IS POSSIBLE AWAY
FROM THE S COAST. IN ADDITION...GUSTY E/NE WINDS WILL CONTINUE
OVER THE CAPE/ISLANDS AND E COASTAL MA.
THIS IS A DIFFICULT SNOWFALL FORECAST DUE TO THE UNCERTAINTY IN
THE NORTHWARD EXTENT OF MID LEVEL WARMING AND HOW MUCH ENHANCEMENT
OCCURS WITH LOW LEVEL JET. OUR CURRENT FORECAST IS FOR 8-12"
NORTH OF THE PIKE AND 4-8" FROM BOS NWD ALONG COASTAL ESSEX
COUNTY. 2-6" N OF HFD-PVD-TAN TO THE MASS PIKE AND A COATING TO
2" ALONG THE S COAST.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
HIGHLIGHTS...
* ANOTHER SYSTEM WILL BRING A GOOD SOAKING ACROSS SNE ON
SATURDAY WHILE SOUTHERN NH MAY SEE SOME MIXED PRECIP EARLY SAT
MORNING.
* CHILLY TEMPS FOLLOW SUN THROUGH TUE
* MODERATING TEMPS BY WED
DETAILS...
FRIDAY...MODERATE TO HIGH CONFIDENCE.
UPPER LEVEL RIDGE WILL MOVE OVER THE REGION DURING THE DAY ALLOWING
FOR HIGH PRESSURE TO SET UP. THERE MAY STILL BE A FEW LINGERING
SHOWERS/DRIZZLE/FLURRIES FROM THE EXITING SYSTEM AS LOW LEVELS ARE
STILL QUIET DRY. HOWEVER KEPT POPS VERY LOW TO ACCOUNT FOR
UNCERTAINTY. EXPECT MAINLY LOW CLOUDS THROUGH THE DAY ON FRIDAY AS
THE MID AND UPPER LEVELS ARE QUIET DRY.
FRIDAY NIGHT - SATURDAY...MODERATE CONFIDENCE.
A STOUT TROUGH OVER THE CENTRAL CONUS WILL MAKE ITS WAY TOWARDS NEW
ENGLAND FRIDAY EVENING. THIS WILL BRING A SURFACE LOW PRESSURE
SYSTEM ACROSS THE GREAT LAKES AND INTO ONTARIO BY SATURDAY MID
MORNING. THIS SYSTEM WILL PUSH OUT A VERY STRONG COLD FRONT ACROSS
SOUTHERN NEW ENGLAND. BECAUSE OF THE STRENGTH OF THIS
SYSTEM...PRESSURE GRADIENT IS EXTREMELY TIGHT AND EXPECT WINDY
CONDITIONS AREA WIDE EARLY SATURDAY MORNING THROUGH THE EVENING
HOURS. TEMPERATURES WILL START OUT BELOW FREEZING ESP ACROSS
NORTHERN MASS AND SOUTHERN NEW HAMPSHIRE. AS PRECIP MOVES IN...A MIX
PRECIPITATION WILL OCCUR DURING THE MORNING HOURS. STILL TO MUCH
UNCERTAINTY RIGHT NOW TO PUT AMOUNTS OR EXACT LOCATION WITH THE
RAIN/MIX PRECIP LINE WILL SET UP AS WELL AS TIMING OF THE SWITCHOVER
TO ALL RAIN. SINCE THIS SYSTEM IS DEPENDING AS IT APPROACHES THE
AREA...STRONG WAA WILL MOVE IN AHEAD OF IT INCREASING 850MB TEMPS TO
8-10C. THEREFORE EXPECT SATURDAY TO BE THE WARMEST DAY OF THE WEEK
AS TEMPS WILL REACH WELL INTO THE 50S. WITH INCREASING MOISTURE DUE
TO STRONG SOUTHERLY WINDS AND A STOUT COLD FRONT...CONVECTION IS NOT
OUT OF THE QUESTION. APPEARS THAT THE NAM IS MORE GUN-HO THEN THE
GFS...AND WITH THE MOISTURE/LIFT/AND INSTABILITY CANNOT RULE OUT
THUNDER SO HAVE INSERTED IT INTO THE FORECAST. BOTTOM LINE IS
SATURDAY COULD GET QUITE MESSY WITH VERY STRONG WINDS THROUGHOUT THE
DAY...MIXED PRECIP ACROSS THE NORTHERN TIER AND THUNDERSTORMS ACROSS
THE SOUTHERN HALF OF THE FORECAST AREA INCLUDING THE WATERS. STAY
TUNE AS THIS SYSTEM WILL EVOLVE MORE OVER THIS WEEK.
SATURDAY NIGHT THROUGH MONDAY NIGHT...LOW CONFIDENCE.
THE SHOWERS SHOULD HAVE PRETTY MUCH EXITED THE SOUTHEAST NEW ENGLAND
COAST BY EARLY SAT EVENING...AS THE COLD FRONT WORKS THROUGH THE
REGION.
HOWEVER...WE ARE GOING TO HAVE TO WATCH A COUPLE WAVES OF LOW
PRESSURE THAT FORM ON THE FRONT...WHICH WILL BE HUNG UP OFF THE
ATLANTIC COAST. THE LATEST GFS/ECMWF KEEP BOTH WAVES OF
LOW PRESSURE FAR ENOUGH SOUTHEAST OF THE REGION TO KEEP MOST OF THE
PRECIPITATION OFF THE SOUTHEAST NEW ENGLAND COAST. HOWEVER...A FEW
OF THE GFS ENSEMBLES AND THE LATEST GGEM SHOW THE POTENTIAL FOR A
TRACK CLOSER TO THE COAST. LOW CONFIDENCE AT THIS TIME...BUT DID
INCLUDE SOME LOW POPS TO COVER THIS POTENTIAL. IF PRECIPITATION
DOES MAKE IT FAR ENOUGH WEST...IT MAY BE COLD ENOUGH TO SUPPORT SOME
WINTRY PRECIPITATION. ITS A LOW PROBABILITY AT THIS POINT...BUT
CERTAINLY WILL NEED TO BE WATCHED.
TUESDAY AND WEDNESDAY...MODERATE TO HIGH CONFIDENCE.
IT SHOULD START OFF QUITE COLD TUE MORNING WITH HIGH PRESSURE
OVERHEAD. HOWEVER...TEMPERATURES SHOULD MODERATE SIGNIFICANTLY BY
WED AS THE HIGH MOVES OFF THE COAST WITH A RETURN SOUTHWEST FLOW OF
AIR. EXPECT DRY WEATHER OVER THIS PERIOD.
&&
.AVIATION /21Z WEDNESDAY THROUGH MONDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT
MODERATE...30 PERCENT TO 60 PERCENT
HIGH...GREATER THAN 60 PERCENT
THROUGH 00Z...CONDITIONS LOWERING TO IFR/LIFR IN SNOW WITH RAIN
ALONG THE IMMEDIATE S COAST.
TONIGHT...HIGH CONFIDENCE. WIDESPREAD IFR/LIFR IN SNOW NORTH...
WITH SNOW CHANGING TO MIXED PRECIP/RAIN SOUTH. DRY SLOT MAY
RESULT IN A BRIEF LULL IN THE PRECIP THIS EVENING...BUT ANOTHER
PULSE OF SNOW/MIXED PRECIP EXPECTED AFTER 06Z. EASTERLY WIND GUSTS
TO 30 KT DEVELOPING ACROSS CAPE/ISLANDS AND SE MA.
THURSDAY...MODERATE TO HIGH CONFIDENCE. IFR/LIFR CONDITIONS
AS AREAS OF SNOW NORTH AND MIXED PRECIP/RAIN NEAR THE S COAST
CONTINUE. STEADIEST PRECIP SHOULD BE CONFINED ALONG AND N OF THE
MASS PIKE. E WIND GUSTS TO 30-35 KT POSSIBLE OVER THE OUTER CAPE
AND ACK.
KBOS TERMINAL...HIGH CONFIDENCE IN TAF. EXPECT IFR CONDITIONS TO
PERSIST FOR MUCH OF THE PERIOD. PTYPE MOSTLY SNOW BUT COULD MIX
WITH SLEET OR RAIN AT TIMES TONIGHT.
OUTLOOK...THURSDAY NIGHT THROUGH MONDAY...
FRIDAY...MODERATE CONFIDENCE. MVFR CEILINGS MAY LINGER ESPECIALLY ON
THE COAST. MAY SEE MVFR VSBYS MOVE IN FROM W-E FRI NIGHT AS NEXT
SYSTEM APPROACHES.
SATURDAY...MODERATE CONFIDENCE. PERIODS OF MVFR-IFR CONDITIONS
LIKELY IN RAIN. PRECIP CHANGING OVER TO SNOW SAT NIGHT BUT WILL
TAPER OFF FROM W-E. S WIND GUSTS MAY REACH 25 KT ESPECIALLY ACROSS
THE HIGHER INLAND TERRAIN.
SATURDAY NIGHT THROUGH MONDAY...MODERATE CONFIDENCE. PROBABLY VFR
THE MAJORITY OF THE TIME...BUT A PERIOD OR TWO OF MVFR CONDITIONS
ARE POSSIBLE.
&&
.MARINE...
EXPECT A PERIOD OF GALE FORCE EASTERLY WINDS TONIGHT...MAINLY
OUTER WATERS AS LLJ MOVES INTO THE WATERS. FOCUS FOR GALE FORCE
WINDS ON THU WILL SHIFT TO THE EAST COASTAL MA WATERS...ESPECIALLY
EAST OF CAPE COD TO EAST OF CAPE ANN. SEAS WILL BUILD TO 15 FT
OVER THE EASTERN OUTER WATERS ON THU.
FORTUNATELY THE ASTRONOMICAL TIDES ARE VERY LOW AND SO COASTAL
FLOODING IS NOT ANTICIPATED.
OUTLOOK...THURSDAY NIGHT THROUGH MONDAY...
FRIDAY...NE WINDS GUSTING UP TO 25 KT WILL DIMINISH DURING THE
AFTERNOON...THEN VEER TO SE-S DURING FRI NIGHT AS NEXT SYSTEM
APPROACHES. SEAS REMAIN AOA 5 FT ON THE OPEN WATERS.
SATURDAY...S-SW WINDS GUSTING UP TO 30 KT. SEAS WILL BUILD UP TO 10
FT...HIGHEST ON THE SOUTHERN OUTER WATERS.
SATURDAY NIGHT THROUGH MONDAY...
ENOUGH COLD AIR ADVECTION SHOULD RESULT IN SCA NORTHWEST WIND GUSTS
AND SEAS ACROSS THE OUTER-WATERS FOR A GOOD PORTION OF THE PERIOD.
THERE COULD BE A PERIOD WHERE THE WINDS TURN MORE NORTH NORTHEAST IF
AN OCEAN STORM TRACKS CLOSE ENOUGH TO THE COAST.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...WINTER WEATHER ADVISORY UNTIL 6 AM EST THURSDAY FOR CTZ002>004.
MA...WINTER STORM WARNING UNTIL 6 PM EST THURSDAY FOR MAZ002>010-
012-014-015-026.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR MAZ017-
018.
WINTER WEATHER ADVISORY UNTIL 6 PM EST THURSDAY FOR MAZ013-016.
WINTER WEATHER ADVISORY UNTIL 6 AM EST THURSDAY FOR MAZ011.
NH...WINTER STORM WARNING UNTIL 6 PM EST THURSDAY FOR NHZ011-012-
015.
RI...WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR RIZ002-
004-005.
WINTER WEATHER ADVISORY UNTIL 6 AM EST THURSDAY FOR RIZ001-003.
MARINE...GALE WARNING FROM 1 AM TO 4 PM EST THURSDAY FOR ANZ232-255.
SMALL CRAFT ADVISORY UNTIL 2 AM EST FRIDAY FOR ANZ233>237.
SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 2 AM EST
FRIDAY FOR ANZ230.
GALE WARNING FROM 5 AM THURSDAY TO 2 AM EST FRIDAY FOR ANZ231-
251.
GALE WARNING FROM 1 AM THURSDAY TO 2 AM EST FRIDAY FOR ANZ250-
254.
GALE WARNING FROM 7 PM THIS EVENING TO 3 AM EST THURSDAY FOR
ANZ256.
&&
$$
SYNOPSIS...KJC/FRANK
NEAR TERM...KJC
SHORT TERM...KJC
LONG TERM...DUNTEN/FRANK
AVIATION...KJC/FRANK
MARINE...KJC/FRANK
AREA FORECAST DISCUSSION
NWS TAUNTON MA
349 PM EST WED FEB 29 2012
.SYNOPSIS...
A SERIES OF LOW PRESSURE SYSTEMS PASSING NEAR AND SOUTH OF THE
REGION WILL BRING PERIODS OF ACCUMULATING SNOW AND MIXED
PRECIPITATION INTO THURSDAY. FAST MOVING HIGH PRESSURE WILL BRING
DRY WEATHER ON FRIDAY. LOW PRESSURE PASSING WELL WEST OF THE
REGION WILL RESULT IN RAINY AND MILD WEATHER WITH BLUSTERY WINDS
SATURDAY...FOLLOWED BY DRY CONDITIONS INTO EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
AREA OF MODERATE TO OCCASIONALLY HEAVY SNOW MOVING ACROSS SNE THIS
AFTERNOON WILL LIKELY BRING 2-4" OVER MUCH OF THE INTERIOR THROUGH
00Z. HRRR REFLECTIVITY DOING A PRETTY GOOD JOB WITH CURRENT AREA
OF PRECIP AND CONFINES HEAVIEST SNOWFALL MOSTLY ALONG AND S OF THE
MASS PIKE THROUGH 00Z.
THIS AREA OF SNOWFALL IS ASSOCD WITH THE INITIAL SURGE OF
ISENTROPIC LIFT WHICH WILL BE EXITING EARLY THIS EVENING AS PSEUDO
DRY SLOT TEMPORARILY MOVES IN. THIS WILL RESULT IN PRECIP
INTENSITY DIMINISHING FOR A TIME THIS EVENING. ALSO...MID LEVEL
WARMING MOVING UP FROM THE SW WILL RESULT IN A CHANGEOVER TO
SLEET/FZRA IN THE INTERIOR MAINLY S OF THE PIKE AND TO MAINLY
RAIN ALONG THE S COAST THROUGH THIS EVENING.
NEXT PULSE OF PRECIP MOVES IN FROM THE SW AFTER 06Z AS SFC WAVE
TRACKS S OF NEW ENGLAND. DEVELOPING EASTERLY LLJ ENHANCES THE LOW
LEVEL CONVERGENCE AND INCREASES OMEGA. WE DISCOUNTED THE WARMER
GFS SOLUTION WHICH HAS STRUGGLED WITH THE THERMAL PROFILE...SO
USED NAM/ECMWF BLEND FOR THIS FORECAST.
PTYPE WITH THIS NEXT BATCH OF PRECIP SHOULD BE PRIMARILY SNOW N
OF THE PIKE WITH SOME MIXING WITH SLEET AT TIMES NEAR THE
PIKE...AND COULD MIX WITH RAIN ALONG IMMEDIATE E MA COASTLINE
INCLUDING BOS. THE MORNING COMMUTE WILL LIKELY BE A PROBLEM N OF
THE PIKE. SOUTH OF THE PIKE...WE ARE LOOKING AT MOSTLY A
RAIN/SNOW/SLEET MIXTURE WITH MAINLY RAIN NEAR THE S COAST.
GUSTY E WINDS DEVELOPING ALONG THE COAST...ESPECIALLY
CAPE/ISLANDS.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/...
EXPECT PERIODS OF SNOW OR MIXED PRECIP TO CONTINUE FOR MUCH OF
THURSDAY AS COASTAL LOW SLOWLY MEANDERS S OF ACK FOR MUCH OF THE
DAY. PERSISTENT ELY LOW LEVEL JET WILL FOCUS THE STEADIEST
SNOWFALL ACROSS N ZONES AND PARTICULARLY ACROSS NE MA AND THE
MERRIMACK VALLEY WHERE A PERIOD OF HEAVY SNOW IS POSSIBLE. AS A
RESULT WE EXPANDED THE WINTER STORM WARNING EASTWARD TO INCLUDE
BOS NORTHWARD ALONG COASTAL ESSEX COUNTY.
SOUTH OF THE MASS PIKE...THE PRECIP IS EXPECTED TO BE LIGHTER BUT
THE COLUMN WILL ALSO BE COOLING DURING THE DAY AS THE WINDS BACK.
SO WE EXPECT ANY RAIN OR MIXED PRECIP TO EVENTUALLY CHANGE BACK
TO SNOW BEFORE ENDING. ADDITIONAL MINOR ACCUM IS POSSIBLE AWAY
FROM THE S COAST. IN ADDITION...GUSTY E/NE WINDS WILL CONTINUE
OVER THE CAPE/ISLANDS AND E COASTAL MA.
THIS IS A DIFFICULT SNOWFALL FORECAST DUE TO THE UNCERTAINTY IN
THE NORTHWARD EXTENT OF MID LEVEL WARMING AND HOW MUCH ENHANCEMENT
OCCURRS WITH LOW LEVEL JET. OUR CURRENT FORECAST IS FOR 8-12"
NORTH OF THE PIKE AND 4-8" FROM BOS NWD ALONG COASTAL ESSEX
COUNTY. 2-6" N OF HFD-PVD-TAN TO THE MASS PIKE AND A COATING TO
2" ALONG THE S COAST.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
HIGHLIGHTS...
* ACCUMULATING SNOW AND MIXED PRECIP WILL LAST INTO INTO THU NIGHT
* ANOTHER SYSTEM WILL BRING A GOOD SOAKING ACROSS SNE ON SATURDAY
WHILE SOUTHERN NH MAY SEE SOME MIXED PRECIP EARLY SAT MORNING.
CONFIDENCE...
INCREASING CONFIDENCE ON THE SYSTEM MOVING THROUGH ON THURSDAY.
HIGH CONFIDENCE THAT ACCUMULATING SNOW...INCLUDING WARNING
CRITERIA WILL OCCUR ESP ACROSS NORTHERN MASS AND SOUTHERN NEW
HAMPSHIRE. FOR THE SATURDAY SYSTEM...HIGH CONFIDENCE THAT PRECIP
WILL OCCUR...MODERATE CONFIDENCE ON TIMING AND PRECIP TYPE.
MODELS...
OVERALL MODEL TRENDS LINE UP WITH THIS SYSTEM WHICH HELPS INCREASE
FORECASTERS CONFIDENCE. DECIDED TO LEAN TOWARDS THE NAM/ECMWF RATHER
THAN THE GFS AS IT DOES NOT HANDLE COLD AIR DAMMING ALL TO WELL.
ALSO THE NAM/ECMWF HAVE BEEN HANDING THIS SYSTEM THE PAST FEW RUNS
WELL AND HAS A GOOD TRACK RECORD FOR SYSTEM THIS MONTH. WHILE THE
NAM IS STILL COLDER IN THE VERTICAL PROFILE BLENDING THE ECMWF AND
CANADIAN WILL HELP CORRECT ANY BIAS THAT THE NAM HAS. FOR QPF DID A
BLEND WITH THE SREF/NAM/ECMWF/GFS. ALL MODELS HAVE SIMILAR OUTPUTS
WITH A FEW BEING MORE THAN OTHERS...SO TRENDED TOWARDS AN AVERAGE.
ONE CONCERN IS THE POTENTIAL FOR MESOSCALE BANDING...HAVE TRIED TO
INCORPORATE THAT INTO THE GRIDS. SURFACE TEMPS WHERE TRENDED TO THE
NAM/PREV FORECAST AS MODELS HAVE BEEN COMING IN COOLER THAN THERE
12Z RUNS. OVERALL GENERAL MODEL AGREEMENT WITH THIS SYSTEM.
DETAILS...
COASTAL LOW WILL DEVELOP ACROSS LONG ISLAND MOVE SOUTH OF ACK DURING
THIS TIME FRAME. THIS LOW WILL KEEP PRECIP GOING ACROSS THE AREA
THROUGH THE DAY AND INTO THE OVERNIGHT HOURS. THIS LOW WILL DEEPEN
AS IT MOVES THROUGH AND CAUSE ENHANCEMENT OVER THE REGION...ALONG
AND NORTH OF THE TURNPIKE. RAIN/SNOW LINE WILL CONTINUE TO MOVE
NORTHWARD AS TEMPS INCREASE ACROSS RI/NORTHERN CT AND THE CAPE AS
THICKNESSES MOVES NORTHWARD. ONCE THING TO NOTE IS THE SURFACE
TROUGHING ACROSS THE 95-CORRIDOR. BELIEVE THIS IS WHERE THE COASTAL
FRONT WILL SET UP AS WARM AIR ACROSS THE WATERS WILL MEET THE COLD
AIR OVER THE LAND...WHICH WILL LEAD TO SOME TRICKY AMOUNTS ACROSS
THE COASTAL REGIONS. WHERE THE COASTAL FRONT SETS UP...AND AS
INDICATED BY THE NAM...GOOD MOISTURE TRANSPORT MOVING ACROSS THE
FRONTAL REGION...COULD SEE HIGHER AMOUNTS. BELIEVE THE HIGHEST
AMOUNTS WILL BE NORTH OF THE I-90 CORRIDOR AS THERE WILL BE SOME
ENHANCEMENT FROM THE COASTAL LOW AS IT IS A SLOWER MOVER. SNOW WILL
BEGIN TO TAPER OFF FROM WEST TO EAST BY THE EVENING AND LAST INTO
THE OVERNIGHT HOURS.
FRIDAY...MODERATE TO HIGH CONFIDENCE.
UPPER LEVEL RIDGE WILL MOVE OVER THE REGION DURING THE DAY ALLOWING
FOR HIGH PRESSURE TO SET UP. THERE MAY STILL BE A FEW LINGERING
SHOWERS/DRIZZLE/FLURRIES FROM THE EXITING SYSTEM AS LOW LEVELS ARE
STILL QUIET DRY. HOWEVER KEPT POPS VERY LOW TO ACCOUNT FOR
UNCERTAINTY. EXPECT MAINLY LOW CLOUDS THROUGH THE DAY ON FRIDAY AS
THE MID AND UPPER LEVELS ARE QUIET DRY.
FRIDAY NIGHT - SATURDAY...MODERATE CONFIDENCE.
A STOUT TROUGH OVER THE CENTRAL CONUS WILL MAKE ITS WAY TOWARDS NEW
ENGLAND FRIDAY EVENING. THIS WILL BRING A SURFACE LOW PRESSURE SYSTEM
ACROSS THE GREAT LAKES AND INTO ONTARIO BY SATURDAY MID MORNING. THIS
SYSTEM WILL PUSH OUT A VERY STRONG COLD FRONT ACROSS SOUTHERN NEW
ENGLAND. BECAUSE OF THE STRENGTH OF THIS SYSTEM...PRESSURE GRADIENT
IS EXTREMELY TIGHT AND EXPECT WINDY CONDITIONS AREA WIDE EARLY
SATURDAY MORNING THROUGH THE EVENING HOURS. TEMPERATURES WILL START
OUT BELOW FREEZING ESP ACROSS NORTHERN MASS AND SOUTHERN NEW
HAMPSHIRE. AS PRECIP MOVES IN...A MIX PRECIPITATION WILL OCCUR
DURING THE MORNING HOURS. STILL TO MUCH UNCERTAINTY RIGHT NOW TO
PUT AMOUNTS OR EXACT LOCATION WITH THE RAIN/MIX PRECIP LINE WILL SET
UP AS WELL AS TIMING OF THE SWITCHOVER TO ALL RAIN. SINCE THIS
SYSTEM IS DEPENDING AS IT APPROACHES THE AREA...STRONG WAA WILL
MOVE IN AHEAD OF IT INCREASING 850MB TEMPS TO 8-10C. THEREFORE
EXPECT SATURDAY TO BE THE WARMEST DAY OF THE WEEK AS TEMPS WILL
REACH WELL INTO THE 50S. WITH INCREASING MOISTURE DUE TO STRONG
SOUTHERLY WINDS AND A STOUT COLD FRONT...CONVECTION IS NOT OUT OF
THE QUESTION. APPEARS THAT THE NAM IS MORE GUN-HO THEN THE GFS...AND
WITH THE MOISTURE/LIFT/AND INSTABILITY CANNOT RULE OUT THUNDER SO
HAVE INSERTED IT INTO THE FORECAST. BOTTOM LINE IS SATURDAY COULD
GET QUITE MESSY WITH VERY STRONG WINDS THROUGHOUT THE DAY...MIXED
PRECIP ACROSS THE NORTHERN TIER AND THUNDERSTORMS ACROSS THE
SOUTHERN HALF OF THE FORECAST AREA INCLUDING THE WATERS. STAY TUNE
AS THIS SYSTEM WILL EVOLVE MORE OVER THIS WEEK.
EXTENDED: SUNDAY-TUESDAY...MODERATE CONFIDENCE.
MODELS SEEM TO BE IN SOME AGREEMENT FOR THE EXTENDED WITH A UPPER
LEVEL DISTURBANCE MOVING THROUGH SUNDAY NIGHT INTO MONDAY. HIGH
PRESSURE WILL DOMINATE MONDAY NIGHT THROUGH TUESDAY.
&&
.AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT
MODERATE...30 PERCENT TO 60 PERCENT
HIGH...GREATER THAN 60 PERCENT
THROUGH 00Z...CONDITIONS LOWERING TO IFR/LIFR IN SNOW WITH RAIN
ALONG THE IMMEDIATE S COAST.
TONIGHT...HIGH CONFIDENCE. WIDESPREAD IFR/LIFR IN SNOW NORTH...
WITH SNOW CHANGING TO MIXED PRECIP/RAIN SOUTH. DRY SLOT MAY
RESULT IN A BRIEF LULL IN THE PRECIP THIS EVENING...BUT ANOTHER
PULSE OF SNOW/MIXED PRECIP EXPECTED AFTER 06Z. EASTERLY WIND GUSTS
TO 30 KT DEVELOPING ACROSS CAPE/ISLANDS AND SE MA.
THURSDAY...MODERATE TO HIGH CONFIDENCE. IFR/LIFR CONDITIONS
AS AREAS OF SNOW NORTH AND MIXED PRECIP/RAIN NEAR THE S COAST
CONTINUE. STEADIEST PRECIP SHOULD BE CONFINED ALONG AND N OF THE
MASS PIKE. E WIND GUSTS TO 30-35 KT POSSIBLE OVER THE OUTER CAPE
AND ACK.
KBOS TERMINAL...HIGH CONFIDENCE IN TAF. EXPECT IFR CONDITIONS TO
PERSIST FOR MUCH OF THE PERIOD. PTYPE MOSTLY SNOW BUT COULD MIX
WITH SLEET OR RAIN AT TIMES TONIGHT.
OUTLOOK...THURSDAY NIGHT THROUGH SUNDAY...
FRIDAY...MODERATE CONFIDENCE. MVFR CEILINGS MAY LINGER ESPECIALLY ON
THE COAST. MAY SEE MVFR VSBYS MOVE IN FROM W-E FRI NIGHT AS NEXT
SYSTEM APPROACHES.
SATURDAY...MODERATE CONFIDENCE. PERIODS OF MVFR-IFR CONDITIONS
LIKELY IN RAIN. PRECIP CHANGING OVER TO SNOW SAT NIGHT BUT WILL
TAPER OFF FROM W-E. S WIND GUSTS MAY REACH 25 KT ESPECIALLY ACROSS
THE HIGHER INLAND TERRAIN.
SUNDAY...MODERATE CONFIDENCE. MVFR CIGS/VSBYS POSSIBLE DURING THE
MORNING ACROSS RI/SE MA...OTHERWISE MAINLY VFR.
&&
.MARINE...
EXPECT A PERIOD OF GALE FORCE EASTERLY WINDS TONIGHT...MAINLY
OUTER WATERS AS LLJ MOVES INTO THE WATERS. FOCUS FOR GALE FORCE
WINDS ON THU WILL SHIFT TO THE EAST COASTAL MA WATERS...ESPECIALLY
EAST OF CAPE COD TO EAST OF CAPE ANN. SEAS WILL BUILD TO 15 FT
OVER THE EASTERN OUTER WATERS ON THU.
FORTUNATELY THE ASTRONOMICAL TIDES ARE VERY LOW AND SO COASTAL
FLOODING IS NOT ANTICIPATED.
OUTLOOK...THURSDAY THROUGH SUNDAY...
THURSDAY...E-NE WINDS WILL INCREASE...REACHING GALE FORCE AS A
GALE WARNING IS OUT FOR THE EASTERN WATERS. CONDITIONS WILL THEN
DIMINISH TO SMALL CRAFT CRITERIA THROUGH THU NIGHT. SEAS WILL BUILD
UP TO 15 FEET ON THE EASTERN OPEN WATERS AS WELL.
FRIDAY...NE WINDS GUSTING UP TO 25 KT WILL DIMINISH DURING THE
AFTERNOON...THEN VEER TO SE-S DURING FRI NIGHT AS NEXT SYSTEM
APPROACHES. SEAS REMAIN AOA 5 FT ON THE OPEN WATERS.
SATURDAY...S-SW WINDS GUSTING UP TO 30 KT. SEAS WILL BUILD UP TO 10
FT...HIGHEST ON THE SOUTHERN OUTER WATERS.
SUNDAY...WINDS VEER TO W...BUT GUSTS FORECASTED TO REACH SMALL CRAFT
CRITERIA. SEAS REMAIN AOA 5 FT ON THE OUTER WATERS.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...WINTER WEATHER ADVISORY UNTIL 6 AM EST THURSDAY FOR CTZ002>004.
MA...WINTER STORM WARNING UNTIL 6 PM EST THURSDAY FOR MAZ002>010-
012-014-015-026.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR MAZ017-
018.
WINTER WEATHER ADVISORY UNTIL 6 PM EST THURSDAY FOR MAZ013-016.
WINTER WEATHER ADVISORY UNTIL 6 AM EST THURSDAY FOR MAZ011.
NH...WINTER STORM WARNING UNTIL 6 PM EST THURSDAY FOR NHZ011-012-
015.
RI...WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR RIZ002-
004-005.
WINTER WEATHER ADVISORY UNTIL 6 AM EST THURSDAY FOR RIZ001-003.
MARINE...GALE WARNING FROM 1 AM TO 4 PM EST THURSDAY FOR ANZ232-255.
SMALL CRAFT ADVISORY UNTIL 2 AM EST FRIDAY FOR ANZ233>237.
SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 2 AM EST
FRIDAY FOR ANZ230.
GALE WARNING FROM 5 AM THURSDAY TO 2 AM EST FRIDAY FOR ANZ231-
251.
GALE WARNING FROM 1 AM THURSDAY TO 2 AM EST FRIDAY FOR ANZ250-
254.
GALE WARNING FROM 7 PM THIS EVENING TO 3 AM EST THURSDAY FOR
ANZ256.
&&
$$
SYNOPSIS...KJC
NEAR TERM...KJC
SHORT TERM...KJC
LONG TERM...DUNTEN
AVIATION...KJC/DUNTEN
MARINE...KJC/DUNTEN
AREA FORECAST DISCUSSION
NWS TAUNTON MA
119 PM EST WED FEB 29 2012
.SYNOPSIS...
A SERIES OF LOW PRESSURE SYSTEMS PASSING NEAR AND SOUTH OF THE
REGION WILL BRING PERIODS OF ACCUMULATING SNOW AND MIXED
PRECIPITATION WEDNESDAY AFTERNOON INTO THURSDAY. FAST MOVING HIGH
PRESSURE WILL BRING DRY WEATHER ON FRIDAY. LOW PRESSURE PASSING
WELL WEST OF THE REGION WILL RESULT IN RAINY AND MILD WEATHER WITH
BLUSTERY WINDS SATURDAY...FOLLOWED BY DRY CONDITIONS INTO EARLY
NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
1 PM UPDATE...
SNOW IS RACING INTO SNE EARLY THIS AFTERNOON AND WILL REACH CAPE
COD DURING THE NEXT HOUR. THE PRECIP MAY BEGIN AS A BRIEF PERIOD
OF RAIN ON THE CAPE BUT QUICKLY CHANGE TO SNOW. MOSTLY RAIN
EXPECTED OVER THE ISLANDS WHERE TEMPS IN THE 40S AND DEWPOINTS
CLOSE TO 30. BASED ON LATEST RADAR TRENDS A PERIOD OF MOD/HVY
SNOW IS LIKELY AND RUC SUPPORTS THIS WITH A DECENT SLUG OF QPF
THROUGH 00Z. WE HAVE INCREASED SNOW AMOUNTS THIS AFTERNOON ACROSS
CENTRAL AND W MA...N CT INTO NW RI WHERE 2-4" POSSIBLE BY
EVENING. 1-2" EXPECTED IN THE COASTAL PLAIN ALTHOUGH ACCUMULATION
HERE MAY BE CONFINED TO THE COLDER SURFACES AND GRASSY AREAS AS
TEMPS HOVER AORUND 33. IT STILL APPEARS DRY SLOT WILL BE MOVING
INTO REGION TOWARD 00Z AS THIS INITIAL SHOT OF WAA PRECIP MOVES
OUT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/...
WARMER AIR STARTS TO MOVE OVER SOUTHERN NEW ENGLAND CHANGING THE
SNOW TO MORE OF A WINTRY MIX...MAINLY SOUTH OF I-90 IN MA...CT AND
RI. RAIN SHOULD BE THE DOMINANT TYPE ACROSS CAPE COD AND THE
ISLANDS. WHILE LIGHTER IN INTENSITY...STILL EXPECTING ACCUMULATING
SNOW AND SLEET FOR MOST OF THE REGION.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
HIGHLIGHTS...
* ACCUMULATING SNOW AND MIXED PRECIP WILL LAST INTO INTO THU NIGHT
* ANOTHER SYSTEM WILL BRING A GOOD SOAKING ACROSS SNE ON SATURDAY
WHILE SOUTHERN NH MAY SEE SOME MIXED PRECIP EARLY SAT MORNING.
CONFIDENCE...
INCREASING CONFIDENCE ON THE SYSTEM MOVING THROUGH ON THURSDAY.
HIGH CONFIDENCE THAT ACCUMULATING SNOW...INCLUDING WARNING
CRITERIA WILL OCCUR ESP ACROSS NORTHERN MASS AND SOUTHERN NEW
HAMPSHIRE. FOR THE SATURDAY SYSTEM...HIGH CONFIDENCE THAT PRECIP
WILL OCCUR...MODERATE CONFIDENCE ON TIMING AND PRECIP TYPE.
THURSDAY...MODERATE CONFIDENCE.
THIS WAS THE MAIN FOCUS FOR THIS FORECAST PACKAGE AS THERE ARE STILL
SOME DETAILS THAT NEED TO BE IRONED OUT FOR THIS UPCOMING SYSTEM.
GENERALLY...A THIRD AREA OF PRECIP WILL MOVE ACROSS THE FORECAST
AREA THURSDAY MORNING AS THE SECONDARY LOW DEVELOPS SOUTH OF
NANTUCKET. THIS LOW WILL SLOWLY MOVE EASTWARD THROUGH THE DAY
THURSDAY AND FINALLY EJECT OVER THE ATLANTIC WATERS BY LATE THURSDAY
AS UPPER LEVEL DISTURBANCE PUSHES IT OUT. THIS SYSTEM WILL BRING A
MIX BAG OF PRECIP ACROSS THE AREA CAUSING FOR A MESSY MORNING
COMMUTE ON THURSDAY.
MODELS...
OVERALL MODEL TRENDS LINE UP WITH THIS SYSTEM WHICH HELPS INCREASE
FORECASTERS CONFIDENCE. DECIDED TO LEAN TOWARDS THE NAM/ECMWF RATHER
THAN THE GFS AS IT DOES NOT HANDLE COLD AIR DAMMING ALL TO WELL.
ALSO THE NAM/ECMWF HAVE BEEN HANDING THIS SYSTEM THE PAST FEW RUNS
WELL AND HAS A GOOD TRACK RECORD FOR SYSTEM THIS MONTH. WHILE THE
NAM IS STILL COLDER IN THE VERTICAL PROFILE BLENDING THE ECMWF AND
CANADIAN WILL HELP CORRECT ANY BIAS THAT THE NAM HAS. FOR QPF DID A
BLEND WITH THE SREF/NAM/ECMWF/GFS. ALL MODELS HAVE SIMILAR OUTPUTS
WITH A FEW BEING MORE THAN OTHERS...SO TRENDED TOWARDS AN AVERAGE.
ONE CONCERN IS THE POTENTIAL FOR MESOSCALE BANDING...HAVE TRIED TO
INCORPORATE THAT INTO THE GRIDS. SURFACE TEMPS WHERE TRENDED TO THE
NAM/PREV FORECAST AS MODELS HAVE BEEN COMING IN COOLER THAN THERE
12Z RUNS. OVERALL GENERAL MODEL AGREEMENT WITH THIS SYSTEM.
DETAILS...
COASTAL LOW WILL DEVELOP ACROSS LONG ISLAND MOVE SOUTH OF ACK DURING
THIS TIME FRAME. THIS LOW WILL KEEP PRECIP GOING ACROSS THE AREA
THROUGH THE DAY AND INTO THE OVERNIGHT HOURS. THIS LOW WILL DEEPEN
AS IT MOVES THROUGH AND CAUSE ENHANCEMENT OVER THE REGION...ALONG
AND NORTH OF THE TURNPIKE. RAIN/SNOW LINE WILL CONTINUE TO MOVE
NORTHWARD AS TEMPS INCREASE ACROSS RI/NORTHERN CT AND THE CAPE AS
THICKNESSES MOVES NORTHWARD. ONCE THING TO NOTE IS THE SURFACE
TROUGHING ACROSS THE 95-CORRIDOR. BELIEVE THIS IS WHERE THE COASTAL
FRONT WILL SET UP AS WARM AIR ACROSS THE WATERS WILL MEET THE COLD
AIR OVER THE LAND...WHICH WILL LEAD TO SOME TRICKY AMOUNTS ACROSS
THE COASTAL REGIONS. WHERE THE COASTAL FRONT SETS UP...AND AS
INDICATED BY THE NAM...GOOD MOISTURE TRANSPORT MOVING ACROSS THE
FRONTAL REGION...COULD SEE HIGHER AMOUNTS. BELIEVE THE HIGHEST
AMOUNTS WILL BE NORTH OF THE I-90 CORRIDOR AS THERE WILL BE SOME
ENHANCEMENT FROM THE COASTAL LOW AS IT IS A SLOWER MOVER. SNOW WILL
BEGIN TO TAPER OFF FROM WEST TO EAST BY THE EVENING AND LAST INTO
THE OVERNIGHT HOURS.
FRIDAY...MODERATE TO HIGH CONFIDENCE.
UPPER LEVEL RIDGE WILL MOVE OVER THE REGION DURING THE DAY ALLOWING
FOR HIGH PRESSURE TO SET UP. THERE MAY STILL BE A FEW LINGERING
SHOWERS/DRIZZLE/FLURRIES FROM THE EXITING SYSTEM AS LOW LEVELS ARE
STILL QUIET DRY. HOWEVER KEPT POPS VERY LOW TO ACCOUNT FOR
UNCERTAINTY. EXPECT MAINLY LOW CLOUDS THROUGH THE DAY ON FRIDAY AS
THE MID AND UPPER LEVELS ARE QUIET DRY.
FRIDAY NIGHT - SATURDAY...MODERATE CONFIDENCE.
A STOUT TROUGH OVER THE CENTRAL CONUS WILL MAKE ITS WAY TOWARDS NEW
ENGLAND FRIDAY EVENING. THIS WILL BRING A SURFACE LOW PRESSURE SYSTEM
ACROSS THE GREAT LAKES AND INTO ONTARIO BY SATURDAY MID MORNING. THIS
SYSTEM WILL PUSH OUT A VERY STRONG COLD FRONT ACROSS SOUTHERN NEW
ENGLAND. BECAUSE OF THE STRENGTH OF THIS SYSTEM...PRESSURE GRADIENT
IS EXTREMELY TIGHT AND EXPECT WINDY CONDITIONS AREA WIDE EARLY
SATURDAY MORNING THROUGH THE EVENING HOURS. TEMPERATURES WILL START
OUT BELOW FREEZING ESP ACROSS NORTHERN MASS AND SOUTHERN NEW
HAMPSHIRE. AS PRECIP MOVES IN...A MIX PRECIPITATION WILL OCCUR
DURING THE MORNING HOURS. STILL TO MUCH UNCERTAINTY RIGHT NOW TO
PUT AMOUNTS OR EXACT LOCATION WITH THE RAIN/MIX PRECIP LINE WILL SET
UP AS WELL AS TIMING OF THE SWITCHOVER TO ALL RAIN. SINCE THIS
SYSTEM IS DEPENDING AS IT APPROACHES THE AREA...STRONG WAA WILL
MOVE IN AHEAD OF IT INCREASING 850MB TEMPS TO 8-10C. THEREFORE
EXPECT SATURDAY TO BE THE WARMEST DAY OF THE WEEK AS TEMPS WILL
REACH WELL INTO THE 50S. WITH INCREASING MOISTURE DUE TO STRONG
SOUTHERLY WINDS AND A STOUT COLD FRONT...CONVECTION IS NOT OUT OF
THE QUESTION. APPEARS THAT THE NAM IS MORE GUN-HO THEN THE GFS...AND
WITH THE MOISTURE/LIFT/AND INSTABILITY CANNOT RULE OUT THUNDER SO
HAVE INSERTED IT INTO THE FORECAST. BOTTOM LINE IS SATURDAY COULD
GET QUITE MESSY WITH VERY STRONG WINDS THROUGHOUT THE DAY...MIXED
PRECIP ACROSS THE NORTHERN TIER AND THUNDERSTORMS ACROSS THE
SOUTHERN HALF OF THE FORECAST AREA INCLUDING THE WATERS. STAY TUNE
AS THIS SYSTEM WILL EVOLVE MORE OVER THIS WEEK.
EXTENDED: SUNDAY-TUESDAY...MODERATE CONFIDENCE.
MODELS SEEM TO BE IN SOME AGREEMENT FOR THE EXTENDED WITH A UPPER
LEVEL DISTURBANCE MOVING THROUGH SUNDAY NIGHT INTO MONDAY. HIGH
PRESSURE WILL DOMINATE MONDAY NIGHT THROUGH TUESDAY.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT
MODERATE...30 PERCENT TO 60 PERCENT
HIGH...GREATER THAN 60 PERCENT
THROUGH 00Z...CONDITIONS LOWERING TO IFR/LIFR IN SNOW.
TONIGHT...HIGH CONFIDENCE. WIDESPREAD IFR/LIFR IN SNOW NORTH...
WITH SNOW CHANGING TO MIXED PRECIP/RAIN NEAR THE SOUTH COAST. DRY
SLOT MAY RESULT IN A BRIEF LULL IN THE PRECIP THIS EVENING...BUT
ANOTHER PULSE OF SNOW/MIXED PRECIP EXPECTED AFTER 06Z. EASTERLY
WIND GUSTS TO 30 KT DEVELOPING ACROSS CAPE/ISLANDS AND SE MA.
THURSDAY...MODERATE TO HIGH CONFIDENCE. IFR/LIFR CONDITIONS
AS AREAS OF SNOW NORTH AND MIXED PRECIP/RAIN NEAR THE S COAST
CONTINUE. STEADIEST PRECIP SHOULD BE CONFINED ALONG AND N OF THE
MASS PIKE. E WIND GUSTS TO 30-35 KT POSSIBLE OVER THE OUTER CAPE
AND ACK.
KBOS TERMINAL...HIGH CONFIDENCE IN TAF. EXPECT IFR CONDITIONS TO
PERSIST FOR MUCH OF THE PERIOD. PTYPE MOSTLY SNOW BUT COULD MIX
WITH SLEET OR RAIN AT TIMES TONIGHT.
OUTLOOK...THURSDAY NIGHT THROUGH SUNDAY...
FRIDAY...MODERATE CONFIDENCE. MVFR CEILINGS MAY LINGER ESPECIALLY ON
THE COAST. MAY SEE MVFR VSBYS MOVE IN FROM W-E FRI NIGHT AS NEXT
SYSTEM APPROACHES.
SATURDAY...MODERATE CONFIDENCE. PERIODS OF MVFR-IFR CONDITIONS
LIKELY IN RAIN. PRECIP CHANGING OVER TO SNOW SAT NIGHT BUT WILL
TAPER OFF FROM W-E. S WIND GUSTS MAY REACH 25 KT ESPECIALLY ACROSS
THE HIGHER INLAND TERRAIN.
SUNDAY...MODERATE CONFIDENCE. MVFR CIGS/VSBYS POSSIBLE DURING THE
MORNING ACROSS RI/SE MA...OTHERWISE MAINLY VFR.
&&
.MARINE...
LIGHT WINDS THROUGH THIS MORNING...THEN EASTERLY WINDS WILL
INCREASE LATER TODAY AND ESPECIALLY TONIGHT AS A LOW-LEVEL JET
MOVES NORTH ACROSS THE WATERS. WIND GUSTS UP TO 40 KT ARE POSSIBLE
TONIGHT...ESPECIALLY ACROSS THE EASTERN COASTAL WATERS.
FORTUNATELY THE ASTRONOMICAL TIDES ARE VERY LOW AND SO COASTAL
FLOODING IS NOT ANTICIPATED.
OUTLOOK...THURSDAY THROUGH SUNDAY...
THURSDAY...E-NE WINDS WILL INCREASE...REACHING GALE FORCE AS A
GALE WARNING IS OUT FOR THE EASTERN WATERS. CONDITIONS WILL THEN
DIMINISH TO SMALL CRAFT CRITERIA THROUGH THU NIGHT. SEAS WILL BUILD
UP TO 15 FEET ON THE EASTERN OPEN WATERS AS WELL.
FRIDAY...NE WINDS GUSTING UP TO 25 KT WILL DIMINISH DURING THE
AFTERNOON...THEN VEER TO SE-S DURING FRI NIGHT AS NEXT SYSTEM
APPROACHES. SEAS REMAIN AOA 5 FT ON THE OPEN WATERS.
SATURDAY...S-SW WINDS GUSTING UP TO 30 KT. SEAS WILL BUILD UP TO 10
FT...HIGHEST ON THE SOUTHERN OUTER WATERS.
SUNDAY...WINDS VEER TO W...BUT GUSTS FORECASTED TO REACH SMALL CRAFT
CRITERIA. SEAS REMAIN AOA 5 FT ON THE OUTER WATERS.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...WINTER WEATHER ADVISORY UNTIL 6 AM EST THURSDAY FOR CTZ002>004.
MA...WINTER STORM WARNING UNTIL 6 PM EST THURSDAY FOR MAZ002>006-
008>010-012-026.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR MAZ017-
018.
WINTER WEATHER ADVISORY UNTIL 6 PM EST THURSDAY FOR MAZ007-
013>016.
WINTER WEATHER ADVISORY UNTIL 6 AM EST THURSDAY FOR MAZ011.
NH...WINTER STORM WARNING UNTIL 6 PM EST THURSDAY FOR NHZ011-012-
015.
RI...WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR RIZ002-
004-005.
WINTER WEATHER ADVISORY UNTIL 6 AM EST THURSDAY FOR RIZ001-003.
MARINE...GALE WARNING FROM 3 AM TO 4 PM EST THURSDAY FOR ANZ232-255.
SMALL CRAFT ADVISORY FROM 4 PM THIS AFTERNOON TO 2 AM EST
FRIDAY FOR ANZ233>237-256.
SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 2 AM EST
FRIDAY FOR ANZ230.
GALE WARNING FROM 7 AM THURSDAY TO 2 AM EST FRIDAY FOR ANZ231-
251.
GALE WARNING FROM 1 AM THURSDAY TO 2 AM EST FRIDAY FOR ANZ250-
254.
&&
$$
SYNOPSIS...BELK/DUNTEN
NEAR TERM...KJC
SHORT TERM...BELK
LONG TERM...DUNTEN
AVIATION...KJC/DUNTEN
MARINE...BELK/DUNTEN
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
1005 PM EST THU MAR 1 2012
.SYNOPSIS...
A WEAKENING COLD FRONT STALLING NORTH AND WEST OF THE AREA
OVERNIGHT. A STRONG COLD FRONT WILL THEN MOVE THROUGH THE AREA
LATE SATURDAY AFTERNOON AND SATURDAY EVENING. HIGH PRESSURE WILL
BUILD BACK INTO THE REGION ON SUNDAY AND WILL REMAIN THE DOMINANT
WEATHER FEATURE THROUGH MUCH OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
THIS EVENING...ANOTHER UNSEASONABLY WARM AND HUMID SETUP FOR OUR
REGION AS A NEARLY STATIONARY FRONTAL BOUNDARY EXTENDS FROM FAR
NW SOUTH CAROLINA INTO NE NORTH CAROLINA. WITH S TO SW SURFACE
FLOW THROUGH THE LOWER LEVELS AND SURFACE DEW POINTS IN THE LOWER
60S...WE THINK TEMPS WILL BE SLOW TO FALL OVERNIGHT...ESPECIALLY
IF THE STEADY STREAM OF MID CLOUDS CONTINUE OVER GEORGIA AND SOUTH
CAROLINA.
REGIONAL SOUNDINGS AND RUC MESOANALYSIS SHOW THE MID LEVELS HAVE
BECOME MORE STABLE SINCE LATE AFTERNOON BUT A FEW ISOLATED SHOWERS
CONTINUE TO DOT THE FORECAST AREA. MODELS INDICATE PWATS SURGING N
OVERNIGHT WITH GULF MOISTURE WORKING INTO THE REGION ALONG WITH
IMPROVING MID LEVEL LAPSE RATES LATE. WE HAVE NOT ALTERED POPS
TOO MUCH OVERNIGHT...KEEPING 20/30 RANGE GOING FOR OUR SOUTH
CAROLINA ZONES IN TANDEM WITH THE BELT OF DEEPER MOISTURE LIFTING
N THROUGH THE CAROLINAS.
THE NOCTURNAL INVERSION IS EXPECTED TO TRAP ABUNDANT LOW LEVEL
MOISTURE LATE TONIGHT...ESPECIALLY IN AREAS WHERE DECENT RAINFALL
OCCURRED. CONTINUE TO INCLUDE MENTION OF PATCHY FOG AFTER MIDNIGHT
AND INTO THE EARLY MORNING HOURS ON FRIDAY.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/...
MODEL SOLUTIONS ARE IN RELATIVELY GOOD AGREEMENT THROUGH THE SHORT
TERM PERIODS THIS AFTERNOON...WITH JUST SOME MINOR DIFFERENCES NOTED
WITH RESPECT TO THE COLD FRONTAL PASSAGE LATE SATURDAY AFTERNOON AND
SATURDAY EVENING.
FRIDAY AND FRIDAY NIGHT...A WARM FRONT WILL LIFT NORTHWARD
THROUGH NORTHERN PORTIONS OF THE FORECAST AREA FRIDAY
MORNING...WITH RIDGING THEN BUILDING BACK INTO THE REGION FRIDAY
AFTERNOON AND FRIDAY NIGHT. MOISTURE TRANSPORT ON THE NOSE OF
25-30 KNOT H85 JET ALONG WITH MID-LEVEL LAPSE RATES AROUND 7 C/KM
WILL NECESSITATE SLIGHT CHANCE/LOW CHANCE POPS FOR
SHOWERS/THUNDERSTORMS ACROSS NORTHERN ZONES FRIDAY MORNING. THE
ACTIVITY ASSOCIATED WITH THE WARM FRONT SHOULD BE NORTH OF THE
SOUTH SANTEE RIVER BY NOON FRIDAY...AND WITH NO LARGE SCALE
FORCING MECHANISM IN PLACE TO PROVIDE ASCENT FRIDAY AFTERNOON AND
FRIDAY NIGHT...WILL KEEP THE FORECAST RAIN FREE. LOW LEVEL
THICKNESS VALUES SUPPORT HIGHS IN THE MID 80S...BUT WITH MORNING
CLOUD COVER AND SKIES NOT CLEARING OUT ENTIRELY DURING THE
AFTERNOON...WE DON/T EXPECT TO REACH VALUES QUITE THIS HIGH. WILL
KEEP FORECAST MAX TEMPERATURES AROUND 80 TO THE LOWER 80S AWAY
FROM THE COAST. OVERNIGHT LOWS ARE EXPECTED TO BOTTOM OUT IN THE
LOWER 60S.
SATURDAY THROUGH SUNDAY...DEEP SOUTHWESTERLY FLOW WILL BE IN
PLACE TO START THINGS OFF SATURDAY IN ADVANCE OF AN APPROACHING
COLD FRONT. THIS COLD FRONT WILL MOVE THROUGH THE FORECAST AREA
LATE SATURDAY AFTERNOON AND SATURDAY EVENING...BUT WON/T PROGRESS
TOO FAR OFF THE COAST INITIALLY. THE COLD FRONT WILL STALL NEAR
THE GULF STREAM SATURDAY NIGHT...AWAITING THE PUSH OF A STRONG
UPPER LEVEL TROUGH EARLY SUNDAY TO KICK IT FURTHER OUT TO SEA.
HIGH PRESSURE WILL THEN BUILD BACK INTO THE AREA SUNDAY AFTERNOON.
AS FOR FORECAST DETAILS...WILL KEEP SHOWERS/ISOLATED THUNDERSTORMS
CONFINED TO WESTERN ZONES SATURDAY MORNING...WITH RAIN FREE
CONDITIONS ANTICIPATED FOR COASTAL ZONES. DEEPER MOISTURE AND BETTER
FORCING FOR ASCENT WILL OVERSPREAD THE FORECAST AREA WITH THE
APPROACH OF THE COLD FRONT SATURDAY AFTERNOON...SO WILL CARRY LIKELY
POPS FOR SHOWERS/THUNDERSTORMS ACROSS THE VAST MAJORITY OF THE AREA.
STILL QUITE A BIT OF UNCERTAINTY WITH RESPECT TO THE POTENTIAL FOR
SEVERE WEATHER...AS IT WILL BE HIGHLY DEPENDENT ON THE AMOUNT OF
SURFACE BASED INSTABILITY WHICH MANAGES TO OCCUR. MODEL SOLUTIONS
SHOW QUITE A BIT OF MID/HIGH CLOUD COVER WILL BE IN PLACE THROUGH
THE DAY SATURDAY...AND THIS WOULD GREATLY LIMIT THE AMOUNT OF
DESTABILIZATION THAT COULD OCCUR. THE NAM12 SHOWS SURFACE BASED CAPE
VALUES INCREASING TO AROUND 500 J/KG WITH LIFTED INDICES LOWERING TO
BETWEEN -2 AND -3. ALTHOUGH THE INSTABILITY APPEARS THAT IT WILL BE
FAIRLY LIMITED...THE STRONGLY SHEARED ENVIRONMENT AND STRONG WIND
FIELDS ALOFT DO SUGGEST THERE WILL BE SOME POTENTIAL FOR SEVERE
WEATHER. THAT SAID...THE BEST DYNAMIC FORCING FOR ASCENT APPEARS
THAT IT WILL REMAIN DISPLACED WELL TO THE WEST OF THE COLD
FRONT...LIMITING THE POTENTIAL FOR A WELL ORGANIZED SEVERE WEATHER
EVENT...SO WILL HOLD OFF ON MENTIONING SEVERE WEATHER IN THE
HAZARDOUS WEATHER OUTLOOK AT THIS TIME.
THE COLD FRONT WILL STALL JUST OFFSHORE SATURDAY EVENING...KEEPING
DEEP MOISTURE IN PLACE ACROSS THE FORECAST AREA WHILE STRONGER UPPER
LEVEL FORCING FOR ASCENT OVERSPREADS THE REGION IN ADVANCE OF THE
APPROACHING UPPER LEVEL TROUGH. AS A RESULT...WILL CONTINUE TO KEEP
POPS IN THE LIKELY RANGE ALL LOCALES SATURDAY NIGHT. SHOWERS AND
THUNDERSTORMS SHOULD BE ONGOING SATURDAY EVENING ACROSS MUCH OF THE
FORECAST AREA...WITH THE PROBABILITY FOR THUNDER THEN STEADILY
DIMINISHING THROUGH THE NIGHT AS PRECIPITATION TRANSFORMS FROM MORE
OF A SHOWERY NATURE TO A GENERAL LIGHT TO MODERATE RAIN. THE RAIN IS
EXPECTED TO QUICKLY CLEAR THE AREA FROM WEST TO EAST SUNDAY MORNING
AS THE STRONG UPPER LEVEL TROUGH SHIFTS THROUGH THE REGION AND KICKS
THE STALLED OUT COLD FRONT AND ASSOCIATED BAND OF DEEPER MOISTURE
FURTHER OFFSHORE AND INTO THE ATLANTIC.
TEMPERATURES ARE EXPECTED TO TOP OUT IN THE MID TO UPPER 70S ON
SATURDAY...WITH LOWS SATURDAY NIGHT IN THE MID TO UPPER 40S. MUCH
COOLER CONDITIONS ARE EXPECTED ON SUNDAY...WITH HIGHS IN THE LOWER
60S MOST LOCALES.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
A SECONDARY COLD FRONT WILL MOVE THROUGH ON MONDAY...BUT WITH THE
DRY WEST AND NW FLOW ALOFT IT/LL COME THROUGH DRY AND GENERALLY FREE
OF EVEN ANY CLOUD COVER. HIGH PRESSURE THEN BUILDS FROM THE OH/TN
VALLEYS IN WAKE OF THIS FRONT...AND SHIFTS TOWARD THE MID ATLANTIC
COAST TUESDAY. THE HIGH WILL THEN PROGRESS INTO THE ATLANTIC FOR
WEDNESDAY AND THURSDAY...AND AS IT DOES SO WE EXPECT A COASTAL TROUGH
TO DEVELOP OVER THE NEARBY ATLANTIC WATERS. THE RETURN OF MOISTURE
WILL BE SLOW...BUT GRADUAL WITH THE SYNOPTIC FLOW BECOMING NE AND
EAST DURING THE MIDDLE OF THE WEEK. EVENTUALLY THIS MAY ALLOW FOR A
FEW SHOWERS TO CREEP ONSHORE...BUT NOTHING MORE THAN ISOLATED
ACTIVITY IS EXPECTED AT THIS TIME. TEMPS LOOK TO BE NEAR OR EVEN
BELOW NORMAL THROUGH WEDNESDAY...WITH SOME MODERATION THURSDAY.
&&
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
PROGRESSIVE WEATHER PATTERN AND FAST UPPER JETS CONTINUE TO MAKE
FORECAST CONFIDENCE LOWER THAN USUAL. THE MAIN QUEST TONIGHT
REVOLVES AROUND CIGS AND VSBYS AFTER MIDNIGHT AND ESPECIALLY
TOWARD DAWN. POTENTIAL FOR FOG/STRATUS TO EXPAND OVER SE GEORGIA
LOOKS GOOD WITH A DRIER LAYER MOVING IN FROM THE SW LATE OVER A
MOIST SURFACE LAYER AND DECENT LOW LEVEL INVERSION. WE MAINTAINED
THINKING FROM OUR 18Z TAF CYCLE WITH MOSTLY MVFR CONDITIONS
LATE...CHANCES FOR IFR AT KSAV DO SEEM A BIT BETTER. BY FRI
AFTERNOON... WE SHOULD BE DRY AND WARM...BECOMING BREEZY AS THE
MIXED LAYER DEEPENS. VFR SHOULD PREVAIL AFTER LATE MORNING AT BOTH
TERMINALS.
EXTENDED AVIATION OUTLOOK...MVFR OR LOWER CIGS/VSBYS APPEAR TO BE A
FAIRLY GOOD PROBABILITY SATURDAY NIGHT THROUGH EARLY SUNDAY AS A
SLOW MOVING COLD FRONT MOVES THROUGH WITH WIDESPREAD SHOWERS AND
THUNDERSTORMS. VFR CONDITIONS WILL RETURN SUNDAY AFTERNOON THROUGH
TUESDAY AS HIGH PRESSURE BUILDS BACK INTO THE AREA. WIND SHEAR AND/OR
GUSTY SURFACE WINDS WILL IMPACT THE TERMINALS FRIDAY NIGHT THROUGH
SATURDAY.
&&
.MARINE...
SW FLOW OVERNIGHT...IN THE 10-15 KT RANGE THIS EVENING...DIMINISHING
SEAWARD AS THE LOW LEVEL JET SLOWLY WEAKENS. SEAS 2 TO 4 FT FOR
THE MOST PART...LOWEST AROUND GRAYS REEF AND HIGHEST FROM BUOY SIX
OFF THE CHARLESTON COUNTY OUT TO BUOY 41004 AND PERHAPS WELL OFF
THE GEORGIA COAST BEYOND 40 NM OFFSHORE.
FRIDAY THROUGH TUESDAY...A WEAK WARM FRONT WILL LIFT NORTHWARD
THROUGH THE SOUTH CAROLINA WATERS FRIDAY MORNING. A STRONG COLD
FRONT WILL APPROACH FROM THE WEST ON SATURDAY AND MOVE THROUGH THE
MARINE AREA SATURDAY NIGHT. HIGH PRESSURE WILL THEN BUILD BACK
INTO THE REGION ON SUNDAY AND WILL REMAIN THE DOMINANT WEATHER
FEATURE THROUGH EARLY NEXT WEEK.
INCREASING SOUTH-SOUTHWEST FLOW IN ADVANCE OF THE COLD FRONT COULD
LEAD TO SMALL CRAFT HEADLINES ACROSS PORTIONS OF THE WATERS FRIDAY
NIGHT THROUGH SUNDAY FOR WINDS/SEAS OR A COMBINATION OF THE TWO.
CONDITIONS ARE EXPECTED TO REMAIN BELOW HEADLINE THRESHOLDS SUNDAY
NIGHT THROUGH MONDAY. SMALL CRAFT CONDITIONS MAY AFFECT PORTIONS OF
THE WATERS AGAIN MONDAY NIGHT AND TUESDAY AS THE GRADIENT PINCHES
DUE TO COASTAL TROUGH DEVELOPMENT OFF THE SOUTHEAST COAST.
&&
.CLIMATE...
RECORD MAX TEMPS FOR MARCH 2...
KCHS...85 SET IN 1997 AND PREVIOUS YEARS.
KCHL...81 SET IN 1976.
KSAV...86 SET IN 1951.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
112 PM EST WED FEB 29 2012
.PREV DISCUSSION...
UPDATE...
/ISSUED 1141 AM EST WED FEB 29 2012/
CURRENT SATELLITE ANALYSIS SHOWS CLOUDS STARTING TO BREAK UP IN
CENTRAL GEORGIA. TEMPS WERE LOWER THAN FORECAST FOR THE SOUTHEAST
PART OF THE CWA SO DECIDED TO LOWER THE HIGH BY A FEW DEGREES DOWN
THERE. THE FORECAST DEWPOINTS WERE LOWER THAN WHAT WAS
OBSERVED...SO POPULATED THE DEWPOINT GRIDS WITH THE 12Z RUC THAT
SEEMED TO HAVE A BETTER HANDLE ON THE DEWPOINTS.
WITH THE UPGRADE TO A MODERATE RISK OF SEVERE WEATHER OVER
NORTHERN GEORGIA CHANGED GRIDS TO REPRESENT THIS UPGRADE. DECIDED
TO INCLUDE THE SEVERE WORDING FOR MOST OF THE NORTHERN PART OF THE
CWA. RIGHT NOW IT LOOKS LIKE THE BEST CHANCE OF TORNADOES WILL BE
DURING THE EVENING HOURS. AS THE COLD FRONT PUSHES SOUTH INTO THE
STATE...EXPECT THE STORMS TO TRANSITION INTO A LINE AND DAMAGING
WINDS WOULD THEN BECOME THE MAIN THREAT.
ARG
SHORT TERM /TODAY THROUGH THURSDAY NIGHT/...
/ISSUED 347 AM EST WED FEB 29 2012/
CURRENT SATELLITE LOOP SHOWS A LARGE MOISTURE PLUME EXTENDING FROM
THE GREAT LAKES STATES...DOWN THE MS RIVER VALLEY...ACROSS TX/MX
AND OUT INTO THE PACIFIC. THE PARENT LOW CENTER IS SPINNING AND
DEEPENING ALONG THE NE/IA/SD BORDERS. THIS LOW CENTER IS EXPECTED
TO MOVE NE OVER THE NEXT 36 HOURS BECOMING CENTERED OVER THE NEW
ENGLAND STATES BY 12-18Z THU. ITS TRAILING COLD FRONT WILL ALSO
CONTINUE MOVING EAST...PUSHING INTO NW GA BY 00-06Z THU. WITH THE
WARM FRONT WELL NORTH GA WE WILL BE IN THE WARM SECTOR OF THIS
SYSTEM PRETTY MUCH ALL DAY TODAY. WITH DEWPOINTS IN THE UPPER 50S
AND LOWER 60S ACROSS THE REGION AND TEMPS EXPECTED IN THE 70S
TODAY...BOTH THE GFS AND ECMWF KEEP PRECIP ACROSS THE AREA ALL DAY
TODAY. THE LOCAL WRF MODEL KEEPS PRECIP CONFINED NEAR THE COLD
FRONT AND DOES NOT BRING ANY DECENT SHOWERS OR THUNDERSTORMS INTO
THE STATE UNTIL AFTER 00Z THU. HAVE COMPROMISED BETWEEN THE
3...WILL KEEP PRECIP ACROSS NORTH GA ALL DAY AND MOVE IT SLOWLY
SOUTHWARD THROUGH TONIGHT. INSTABILITIES INDICES INCREASE AFTER
00Z THU WITH THE FRONTAL PASSAGE ALSO. MUCAPES GET INTO THE
300-500 J/KG RANGE WITH 0-6KM BULK SHEAR AROUND 60-70 KT. THERE IS
ALSO A 45-55KT LOW LEVEL JET ASSOCIATED WITH THE FRONTAL PASSAGE.
WILL CONTINUE TO MENTION THUNDER TODAY AS THIS ENVIRONMENT WILL
SUPPORT ROTATING UPDRAFTS...AND AN ISOLATED SEVERE STORM/TORNADO
OR TWO. SPC HAS PUT THE NORTHERN HALF OF THE STATE UNDER A SLIGHT
RISK AREA. THE SYSTEM BEGINS TO LOOSE STRENGTH AFTER 06Z THU AS
THE FRONT CONTINUES TO PUSH SOUTH THROUGH THE AREA. POPS AND
THUNDER CHANCES DIMINISH THROUGH THE DAY THURSDAY BEFORE THE NEXT
SYSTEM FRI INTO SAT. TEMPS WILL REMAIN 10-12 DEG ABOVE SEASONAL
NORMS THROUGH THE SHORT TERM.
LONG TERM /FRIDAY THROUGH TUESDAY/...
THE COLD FRONT MENTIONED ABOVE STALL ACROSS CENTRAL/SOUTH GA THU
BEFORE GETTING PULLED BACK NORTH AS A WARM FRONT THU NIGHT AS NEXT
LOW CENTER DEVELOPS. A CLOSED LOW CENTER DEVELOPS OVER OK FRI
MORNING AND LIFTS NE INTO THE GREAT LAKES STATES AS IT DEEPENS
THROUGH SAT MORNING. THIS LOW CENTER PULLS THE FIRST COLD FRONT
NORTHWARD AS A WARM FRONT FRIDAY WITH A SECOND COLD FRONT PUSHING
INTO OUR AREA SAT MORNING. THIS PATTERN WILL PUT GA IN THE WARM
MOIST SECTOR AGAIN DURING THE PRIME HEATING OF THE DAY FRI.
INSTABILITY INDICES PEAK FRI AFTERNOON WITH MUCAPES AROUND 300-500
J/KG AND 0-6KM BULK SHEAR IN THE 50-60 KT RANGE. THIS IS BEGINNING
TO LOOK LIKE IT WILL BE A REPEAT OF WHAT IS EXPECTED TODAY. THIS IS
WHY SPC HAS PUT NW GA UNDER A SLIGHT RISK FOR FRI. WILL DEFINITELY
SEE SOME THUNDERSTORMS FRI JUST NOT SURE ON THE INTENSITY OF THE
STORMS JUST YET. THE FRONT SWEEPS THROUGH THE STATE SAT MORNING WITH
A LARGE HIGH PRESSURE RIDGE BUILDING IN FROM TX SAT AFTERNOON. THIS
RIDGE SETS UP OVER GA AND KEEPS THE AREA DRY THROUGH THE MIDDLE OF
NEXT WEEK. TEMPS FINALLY GET DOWN TO NEAR SEASONAL NORMS DAYS 4-7.
&&
.AVIATION...
18Z UPDATE...
BULK OF PRECIP SHOULD HOLD OFF UNTIL TONIGHT...HOWEVER THERE IS A
CHANCE FOR SOME PRECIP LATE THIS AFTERNOON...MAINLY AT THE
NORTHERN SITES. GIVEN LOW CHANCES THOUGH...AM NOT ADVERTISING IN
THE TAF EXCEPT FOR CB. DID PUSH BACK TIMING OF TSRA IN TAFS. SOME
BREAKS ON VSBY SATELLITE ACROSS EASTERN ALABAMA SO BETWEEN THIS
AND LIFTING CIGS...MVFR CIGS SHOULD BECOME VFR LATER THIS
AFTERNOON. CLOUDS WILL BUILD BACK IN TONIGHT AS FRONT APPROACHES.
WINDS WILL REMAIN SW AND BECOME W TO NW TOMORROW.
//ATL CONFIDENCE...18Z UPDATE...
HIGH CONFIDENCE ON WINDS AND VSBYS. MEDIUM CONFIDENCE ON CIGS. LOW
CONFIDENCE ON TIMING OF PRECIP.
11
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 71 55 76 56 / 20 70 60 50
ATLANTA 72 57 73 61 / 30 70 50 50
BLAIRSVILLE 66 48 70 48 / 70 100 10 50
CARTERSVILLE 73 52 74 54 / 50 80 40 50
COLUMBUS 76 63 77 63 / 20 50 30 40
GAINESVILLE 67 53 73 56 / 40 80 50 50
MACON 74 63 78 61 / 10 50 30 40
ROME 74 53 76 54 / 70 80 10 50
PEACHTREE CITY 73 57 74 58 / 20 60 50 50
VIDALIA 76 63 79 63 / 10 30 20 30
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
11
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
1141 AM EST WED FEB 29 2012
.UPDATE...
CURRENT SATELLITE ANALYSIS SHOWS CLOUDS STARTING TO BREAK UP IN
CENTRAL GEORGIA. TEMPS WERE LOWER THAN FORECAST FOR THE SOUTHEAST
PART OF THE CWA SO DECIDED TO LOWER THE HIGH BY A FEW DEGREES DOWN
THERE. THE FORECAST DEWPOINTS WERE LOWER THAN WHAT WAS
OBSERVED...SO POPULATED THE DEWPOINT GRIDS WITH THE 12Z RUC THAT
SEEMED TO HAVE A BETTER HANDLE ON THE DEWPOINTS.
WITH THE UPGRADE TO A MODERATE RISK OF SEVERE WEATHER OVER
NORTHERN GEORGIA CHANGED GRIDS TO REPRESENT THIS UPGRADE. DECIDED
TO INCLUDE THE SEVERE WORDING FOR MOST OF THE NORTHERN PART OF THE
CWA. RIGHT NOW IT LOOKS LIKE THE BEST CHANCE OF TORNADOES WILL BE
DURING THE EVENING HOURS. AS THE COLD FRONT PUSHES SOUTH INTO THE
STATE,,,EXPECT THE STORMS TO TRANSITION INTO A LINE AND DAMAGING
WINDS WOULD THEN BECOME THE MAIN THREAT.
&&
ARG
.SHORT TERM /TODAY THROUGH THURSDAY NIGHT/...
/ISSUED 347 AM EST WED FEB 29 2012/
CURRENT SATELLITE LOOP SHOWS A LARGE MOISTURE PLUME EXTENDING FROM
THE GREAT LAKES STATES...DOWN THE MS RIVER VALLEY...ACROSS TX/MX
AND OUT INTO THE PACIFIC. THE PARENT LOW CENTER IS SPINNING AND
DEEPENING ALONG THE NE/IA/SD BORDERS. THIS LOW CENTER IS EXPECTED
TO MOVE NE OVER THE NEXT 36 HOURS BECOMING CENTERED OVER THE NEW
ENGLAND STATES BY 12-18Z THU. ITS TRAILING COLD FRONT WILL ALSO
CONTINUE MOVING EAST...PUSHING INTO NW GA BY 00-06Z THU. WITH THE
WARM FRONT WELL NORTH GA WE WILL BE IN THE WARM SECTOR OF THIS
SYSTEM PRETTY MUCH ALL DAY TODAY. WITH DEWPOINTS IN THE UPPER 50S
AND LOWER 60S ACROSS THE REGION AND TEMPS EXPECTED IN THE 70S
TODAY...BOTH THE GFS AND ECMWF KEEP PRECIP ACROSS THE AREA ALL DAY
TODAY. THE LOCAL WRF MODEL KEEPS PRECIP CONFINED NEAR THE COLD
FRONT AND DOES NOT BRING ANY DECENT SHOWERS OR THUNDERSTORMS INTO
THE STATE UNTIL AFTER 00Z THU. HAVE COMPROMISED BETWEEN THE
3...WILL KEEP PRECIP ACROSS NORTH GA ALL DAY AND MOVE IT SLOWLY
SOUTHWARD THROUGH TONIGHT. INSTABILITIES INDICES INCREASE AFTER
00Z THU WITH THE FRONTAL PASSAGE ALSO. MUCAPES GET INTO THE
300-500 J/KG RANGE WITH 0-6KM BULK SHEAR AROUND 60-70 KT. THERE IS
ALSO A 45-55KT LOW LEVEL JET ASSOCIATED WITH THE FRONTAL PASSAGE.
WILL CONTINUE TO MENTION THUNDER TODAY AS THIS ENVIRONMENT WILL
SUPPORT ROTATING UPDRAFTS...AND AN ISOLATED SEVERE STORM/TORNADO
OR TWO. SPC HAS PUT THE NORTHERN HALF OF THE STATE UNDER A SLIGHT
RISK AREA. THE SYSTEM BEGINS TO LOOSE STRENGTH AFTER 06Z THU AS
THE FRONT CONTINUES TO PUSH SOUTH THROUGH THE AREA. POPS AND
THUNDER CHANCES DIMINISH THROUGH THE DAY THURSDAY BEFORE THE NEXT
SYSTEM FRI INTO SAT. TEMPS WILL REMAIN 10-12 DEG ABOVE SEASONAL
NORMS THROUGH THE SHORT TERM.
.LONG TERM /FRIDAY THROUGH TUESDAY/...
THE COLD FRONT MENTIONED ABOVE STALL ACROSS CENTRAL/SOUTH GA THU
BEFORE GETTING PULLED BACK NORTH AS A WARM FRONT THU NIGHT AS NEXT
LOW CENTER DEVELOPS. A CLOSED LOW CENTER DEVELOPS OVER OK FRI
MORNING AND LIFTS NE INTO THE GREAT LAKES STATES AS IT DEEPENS
THROUGH SAT MORNING. THIS LOW CENTER PULLS THE FIRST COLD FRONT
NORTHWARD AS A WARM FRONT FRIDAY WITH A SECOND COLD FRONT PUSHING
INTO OUR AREA SAT MORNING. THIS PATTERN WILL PUT GA IN THE WARM
MOIST SECTOR AGAIN DURING THE PRIME HEATING OF THE DAY FRI.
INSTABILITY INDICES PEAK FRI AFTERNOON WITH MUCAPES AROUND 300-500
J/KG AND 0-6KM BULK SHEAR IN THE 50-60 KT RANGE. THIS IS BEGINNING
TO LOOK LIKE IT WILL BE A REPEAT OF WHAT IS EXPECTED TODAY. THIS IS
WHY SPC HAS PUT NW GA UNDER A SLIGHT RISK FOR FRI. WILL DEFINITELY
SEE SOME THUNDERSTORMS FRI JUST NOT SURE ON THE INTENSITY OF THE
STORMS JUST YET. THE FRONT SWEEPS THROUGH THE STATE SAT MORNING WITH
A LARGE HIGH PRESSURE RIDGE BUILDING IN FROM TX SAT AFTERNOON. THIS
RIDGE SETS UP OVER GA AND KEEPS THE AREA DRY THROUGH THE MIDDLE OF
NEXT WEEK. TEMPS FINALLY GET DOWN TO NEAR SEASONAL NORMS DAYS 4-7.
&&
.AVIATION...
12Z UPDATE...
/ISSUED 703 AM EST WED FEB 29 2012/ MVFR TO CONTINUE FOR THE
BETTER PART OF THE MORNING. SOME DIFFICULTIES IN TIMING OF
CLEARING/LIFTING IN THE AFTERNOON...IN THAT GUIDANCE IS NOT
CONSISTENT WITH DOING THAT ACROSS THE AREA. SPLIT THE DIFFERENCE
AND CLEARED ATL OUT BRIEFLY IN THE AFTERNOON...BUT CONFIDENCE IS
LOW. WINDS WILL BE WESTERLY FOR THE DURATION OF THE PERIOD...WITH
GUSTS UP TO 20KTS AT MAX HEATING. TSRA NOT EXPECTED TO IMPACT
AIRPORTS UNTIL AFTER 21Z.
//ATL CONFIDENCE...
12Z UPDATE...
LOW ON TIMING OF CIGS LIFTING. MEDIUM ON REMAINING ELEMENTS.
27
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 71 55 76 56 / 20 70 30 50
ATLANTA 72 57 73 61 / 30 70 30 50
BLAIRSVILLE 66 48 70 48 / 70 90 10 50
CARTERSVILLE 73 52 74 54 / 50 80 20 50
COLUMBUS 76 63 77 63 / 20 50 20 40
GAINESVILLE 67 53 73 56 / 40 80 30 50
MACON 77 63 78 61 / 10 50 20 40
ROME 74 53 76 54 / 70 80 10 50
PEACHTREE CITY 73 57 74 58 / 20 60 30 50
VIDALIA 80 63 79 63 / 10 30 20 30
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
26
AREA FORECAST DISCUSSION
NWS BOISE ID
908 PM MST TUE FEB 28 2012
.DISCUSSION...THE COLD FRONT ALONG THE OREGON COAST HAS BROUGHT
GUSTY PREFRONTAL SW WINDS TO SE OREGON /G25 MPH KREO/ AND BRIEFLY
VERY LIGHT SNOW /0.01 INCHES/ TO BURNS. THUNDERSTORMS OCCURRED
THIS AFTERNOON AND EVENING OFFSHORE /WA-OREGON/ AND OVER THE
COASTAL WATERS OFF BROOKINGS OREGON. LATEST RUC/NAM ARE SLOWER TO
BRING PRECIPITATION ACROSS OUR AREA WITH THE RUC HOLDING OFF TILL
9Z KBNO-KBKE-KMYL WWD. THE NAM DEVELOPS /OROGRAPHIC/ PCPN OVER
CENTRAL IDAHO BY 6Z WITH BUT THE MAIN QPF EVENT IS WITH AND BEHIND
THE FRONT IN THE NAM. THE NAM SEEMS TO BE THE WAY TO GO PER
OBS/TRENDS. THIS IS NOT THE FIRST TIME COASTAL CONVECTION AND
A LOWER/SLOWER INLAND QPF HAVE SEEMED TO GO TOGETHER. DO LIKE THE
IDEA OF OROGRAPHIC FORCING FOLLOWED BY A ROUND OF HEAVIER
PRECIPITATION WITH AND BEHIND THE FRONT ACROSS BURNS/BAKER
10-12Z...BOISE AROUND 14Z...TWF 17-19Z. GUSTY SE TO S WINDS WILL
SHIFT TO WEST WITH THE FRONT WITH BRIEF GUSTS TO 45 MPH. AS THE
UPPER TROUGH CROSSES THE AREA THIS AFTERNOON STEEP LAPSE RATES AND
NEARLY MARCH INSOLATION WILL PROMOTE STRONG SHOWERS WITH SMALL
HAIL OR ICE PELLETS. THUNDERSTORM PARAMETERS ARE WEAK SO WON/T ADD
A MENTION AT THIS POINT...AND SHOW -1C LI AND 50-100 ML CAPE MAINLY
NORTH OF A LINE FROM BURNS TO BOISE TO IDAHO CITY THIS AFTERNOON.
&&
.AVIATION...AFTER 06Z MVFR/IFR CONDITIONS IN SNOW WILL BECOME
WIDESPREAD IN EASTERN OREGON AND THE WEST CENTRAL IDAHO MOUNTAINS...
SPREADING ACROSS SOUTHWEST IDAHO 14Z-18Z ACCOMPANYING AND FOLLOWING
A COLD FRONT. SNOW AND MOUNTAIN OBSCURATION WILL PERSIST THROUGH
WEDNESDAY WITH GRADUAL IMPROVEMENT AFTER 00Z THURSDAY. EAST TO SOUTH
SURFACE WINDS 10-20 KTS WILL INCREASE TO 15-25 KTS AFTER 09Z THEN
SHIFT TO WEST 15-25 KTS AFTER 18Z. WINDS ALOFT WILL BE SOUTHWEST UP
TO 55 KTS AT 10K FEET MSL.
&&
.PREV DISCUSSION...
SHORT TERM...TONIGHT THROUGH THURSDAY...LARGE STRONG UPPER LEVEL
SYSTEM MOVING SE TOWARD THE PAC NW THIS AFTERNOON. THIS WILL BRING
WINTER WEATHER TO THE REGION TONIGHT AND TOMORROW. WE HAVE
ADJUSTED THE ADVISORIES THAT WERE ISSUED EARLIER. WE NOW HAVE
WINTER STORM WARNINGS FOR SNOW AND BLOWING SNOW IN EFFECT FOR
BAKER COUNTY AND THE WEST-CENTRAL MOUNTAINS FROM LATE THIS EVENING
INTO TOMORROW MORNING...A WINTER STORM WARNING FOR SNOW FOR THE
WEISER RIVER BASIN FOR THE SAME TIME...A WINTER WEATHER ADVISORY
FOR SNOW FOR THE OWYHEES FOR THE SAME TIME...AND A WINTER WEATHER
ADVISORY FOR THE SOUTHWEST HIGHLANDS FROM 5 AM MST TO 5 PM MST
TOMORROW. THIS SYSTEM IS STRONG BUT RELATIVELY DRY. THEREFORE...
THE MAIN IMPACTS WILL COME FROM WIND-BLOWN SNOW IN BAKER COUNTY
AND IN THE WEST-CENTRAL MOUNTAINS. PEAKS IN THE BOISE MTNS WILL
ALSO BE HEAVILY IMPACTED...BUT AREAS WHERE PEOPLE WILL BE WILL
HAVE MUCH LESS WIND AND THEREFORE NO WARNING WAS ISSUED FOR THE
BOISE MTNS. A COLD FRONT ASSOCIATED WITH THIS SYSTEM WILL MOVE
THROUGH THE REGION AS WELL. IT WILL MOVE THROUGH BAKER COUNTY
AROUND 4 AM PST...THROUGH THE REMAINDER OF SE OREGON...THE WEST-
CENTRAL MTNS...AND THE TREASURE VALLEY BETWEEN 6 AM AND 9 AM
MST...AND THROUGH THE BOISE MTNS...SOUTHWEST HIGHLANDS...AND
MAGIC VALLEY BY NOON MST. MOST OF THE PRECIPITATION IN THE HIGHER
ELEVATIONS WILL FALL PRE-FRONTAL DUE TO OROGRAPHIC LIFT. IN THE
LOWER ELEVATIONS...MOST OF THE PRECIPITATION WILL BE ALONG THE
FRONT. IN THE TREASURE VALLEY...THERE WILL BE CONSIDERABLE
SHADOWING BY THE OWYHEES. THIS WILL DRASTICALLY LIMIT SNOWFALL
UNTIL THE FRONT ARRIVES...AND EVEN THEN WE EXPECT JUST A FEW
HUNDREDTHS OF AN INCH OF LIQUID EQUIVALENT. SNOW SHOWERS IN THE
AFTERNOON MAY ADD ANOTHER COUPLE OF HUNDREDTHS...BUT OVERALL VERY
LITTLE IF ANY ACCUMULATION IS EXPECTED IN THE TREASURE VALLEY. IN
THE SOUTHWEST HIGHLANDS...SNOW WILL LINGER IN TO THE AFTERNOON AS
THE FRONT SLOWS AND OROGRAPHIC EFFECTS CONTRIBUTE TO A LONGER
SNOWFALL. TEMPS OVERNIGHT WILL BE MILDER THAN LAST NIGHT DUE TO
CLOUD COVER AND WIND. IN THE TREASURE VALLEY ESPECIALLY... STRONG SE
WINDS WILL KEEP THE TEMPS ABOVE FREEZING...AND THIS WILL MAKE IT
NEARLY IMPOSSIBLE FOR WHAT LITTLE SNOW DOES FALL TO ACCUMULATE ON
THE ROADWAYS IN THE MORNING. HIGHS WED AND THU WILL BE 5 TO 10
DEGREES BELOW NORMAL. SNOW SHOWERS WILL PICK UP AGAIN THU...
ESPECIALLY IN THE SOUTHWEST HIGHLANDS AND IN SOUTHERN TWIN FALLS
COUNTY...AS A SHORT WAVE MOVES THROUGH THE LARGE TROUGH. SNOWFALL
MAY BE ENOUGH FOR NEW ADVISORIES AT THAT TIME.
LONG TERM...THURSDAY NIGHT THROUGH TUESDAY...MODEL AGREEMENT IS
FAIR THROUGH SUNDAY. THURSDAY NIGHT AND FRIDAY WILL BE CLOUDY AND
SHOWERY AS LOW PRESSURE EXITS TO THE EAST...AND HIGH PRESSURE PUSHES
INLAND TOWARD THE WEST COAST. UPPER LEVEL HEIGHTS WILL BE SLOW TO
BUILD HOWEVER...AND THE AREA WILL REMAIN UNDER UNSETTLED NORTHWEST
FLOW ALOFT THROUGH SATURDAY NIGHT. THIS WILL MAINTAIN A CHANCE OF
PRECIPITATION IN THE CENTRAL MOUNTAINS AS MOISTURE STREAMS IN ATOP
THE RIDGE...WITH CLOUDY CONDITIONS ELSEWHERE. BY SUNDAY ALL AREAS
LOOK TO BE WARM AND DRY...AS THE RIDGE AXIS MOVES OVER THE GREAT
BASIN. BEGINNING MONDAY UNCERTAINTY INCREASES...AND WHILE MODELS ARE
DEPICTING SIMILAR FEATURES...THERE ARE MARKED TIMING AND AMPLITUDE
DIFFERENCES. IT APPEARS THAT A WEAK DISTURBANCE OR COLD FRONT WILL
AFFECT THE AREA SOMETIME EARLY IN THE WEEK...BUT NO OTHER DETAILS
ARE CURRENTLY AVAILABLE. THEREFORE...THIS SYSTEM WILL BE EVALUATED
FURTHER AS WE MOVE CLOSER IN TIME TO THE EVENT. ALL IN ALL...THE
AREA LOOKS TO REMAIN UNDER PROGRESSIVE UPPER LEVEL FLOW...WITH
SYSTEMS MOVING THROUGH EVERY FEW DAYS.
&&
.BOI WATCHES/WARNINGS/ADVISORIES...
ID...WINTER STORM WARNING UNTIL 11 AM MST WEDNESDAY IDZ011-033.
WINTER WEATHER ADVISORY UNTIL 11 AM MST WEDNESDAY IDZ029.
WINTER WEATHER ADVISORY FROM 5 AM TO 5 PM MST WEDNESDAY IDZ015.
OR...WINTER STORM WARNING UNTIL 10 AM PST WEDNESDAY ORZ062.
&&
$$
WEATHER.GOV/BOISE
DISCUSSION...VM
AVIATION.....JT
PREV SHORT TERM...SP
PREV LONG TERM....BB/DD
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
621 AM CST WED FEB 29 2012
.DISCUSSION...
610 AM CST
TRENDS BECOMING MORE CLEAR IN TERMS OF CLOUDS AND TEMPS OVER THE
NEXT FEW HOURS. HAVE MADE SOME ADJUSTMENTS TO THE NEAR TERM
FORECAST TO ACCOUNT FOR THESE LATEST TRENDS. WARM FRONTAL BOUNDARY
CONTINUES TO LIFT NORTHEASTWARD AND STRETCHES FROM ROUGHLY
PRINCETON TO KANKAKEE TO LAFAYETTE. TEMPS BEHIND IT HAVE QUICKLY
WARMED INTO THE UPPER 50S TO AROUND 60 DEGREES. HAVE WARMED UP
NORTHERN AREAS TO AROUND 50/LOWER 50S AS THEY SHOULD BE IN THE
WARM SECTOR FOR A SHORT TIME IN THE NEXT FEW HOURS. THE FIRST COOL
FRONT IS RIGHT ON THE HEELS OF THE WARM FRONT BRINGING MUCH DRIER
AND MODESTLY COOLER AIR WITH STATIONS IN WEST CENTRAL ILLINOIS AND
SOUTHEAST IOWA HAVING COOLED SEVERAL DEGREES OVER THE LAST HOUR OR
TWO. THE CHALLENGE WILL BE DETERMINING HOW MUCH WARMING MAY OCCUR
AS THE SUN COMES UP AND MIXING DEEPENS THIS MORNING BEHIND THIS
BOUNDARY AND AHEAD OF THE BETTER PUSH OF COOLER AIR THIS
AFTERNOON. SOUTHWESTERN AREAS MAY SEE A PEAK IN TEMPS NOW WITH A
LOSS OF A FEW DEGREES OVER THE NEXT FEW HOURS...WITH A REBOUND IN
TEMPS AS SUNSHINE INCREASES LATE THIS MORNING. SPEAKING OF
SUN...SUNSHINE IS ON THE WAY WITH STRATUS QUICKLY ERODING
NORTHEASTWARD AND MOST OF THE CWA SHOULD SEE SUNSHINE IN THE NEXT
COUPLE HOURS. HAVE TWEAKED AFTERNOON TEMP TRENDS AS WELL TO SHOW A
BIT BETTER DEFINED COOLING LATE BUT HOURLY TEMP TRENDS MAY NEED
ADJUSTMENTS LEADING UP TO THAT TIME.
MDB
&&
.PREV DISCUSSION...
340 AM CST
A RATHER COMPLEX PATTERN LEADS TO A COMPLICATED SHORT TERM PERIOD OF
THE FORECAST WITH SEVERAL CONCERNS INCLUDING THUNDER POTENTIAL NEXT
FEW HOURS...WIND GUSTS THROUGH THE AFTERNOON...TEMP TRENDS...AND
ADDITIONAL PRECIP CHANCES/TYPE INTO THE EVENING. EARLY MORNING WATER
VAPOR IMAGERY SHOWS THE CLOSED UPPER LOW RESPONSIBLE FOR ALL OF THE
ABOVE SPINNING OVER NORTHWEST IOWA AND HEADING EAST. BEHIND IT...LOW
AMPLITUDE RIDGING IS WORKING ACROSS THE CENTRAL AND NORTHERN ROCKIES
WITH ANOTHER CLOSED UPPER LOW COMING ONSHORE OVER THE PACIFIC
NORTHWEST. THIS LOW WILL BE SIGNIFICANT FOR THE LOCAL AREA FRIDAY.
AT THE SURFACE...LOW PRESSURE CONTINUES SPIN OVER FAR NORTHERN IOWA
AND FAR SOUTHERN MINNESOTA AND IS BEGINNING TO OCCLUDE...WITH A WARM
FRONT EXTENDING SOUTHEASTWARD AND JUST NOW MOVING NORTHWARD INTO THE
EXTREME SOUTHERN CWA...AND A COOL FRONT CROSSING THE MISSISSIPPI
RIVER INTO WEST CENTRAL AND SOUTHWEST ILLINOIS WITH A STRONGER COLD
FRONT TRAILING IT TO THE WEST. BROAD AREA OF WARM ADVECTION SHOWERS
AND THUNDERSTORMS IS EXITING TO THE NORTHEAST WHILE ANOTHER ROUND OF
SHOWERS AND EMBEDDED THUNDERSTORMS LIFTS NORTHEASTWARD AHEAD OF THE
WARM FRONT/OCCLUSION WITH AN EXTENSION SOUTHWARD DOWN THE INITIAL
COOL FRONT.
TODAY AND TONIGHT...THE WARM FRONT WILL CONTINUE TO LIFT
NORTHEASTWARD ACROSS THE AREA OVER THE NEXT FEW HOURS WHILE THE
INITIAL COOL FRONT...WHICH IS REALLY MORE OF MARKER FOR THE LEADING
EDGE OF A DRIER AIR MASS...SPREADS EASTWARD. THE WARM/MOIST SECTOR
BETWEEN THE TWO IS RATHER COMPACT AND IS JUST NOW MOVING INTO THE
FAR SOUTHERN CWA AT 09Z. IN TERMS OF THUNDERSTORMS...LATEST RADAR
TRENDS AND SHORT TERM GUIDANCE BRING THE NEXT BAND OF
SHOWERS/EMBEDDED THUNDER ACROSS THE AREA BETWEEN NOW AND ABOUT 12Z
AS THE WARM FRONT LIFTS NORTHWARD. LAST FEW RADAR SCANS SHOW SOME
NEW DEVELOPMENT ON THE SOUTHERN END OF THE ORIGINAL LINE FROM
GALESBURG TO MACOMB TO QUINCY WHICH APPEARS TO BE RIGHT ALONG THE
DRY BOUNDARY. ANOTHER LINE OF CONVECTION IS ONGOING FROM BLOOMINGTON
SOUTHWARD AND WAS INITIALLY TIED TO THE FRONT BUT NOW APPEARS TO BE
OUT AHEAD OF IT. THIS NEW DEVELOPMENT IS OF SOME CONCERN IN THAT IT
WILL LIKELY CROSS THE SOUTHERN CWA WHICH WILL LIKELY BE IN THE WARM
SECTOR IN THE NEXT FEW HOURS. LATEST SPC MESOANALYSIS SHOWS SURFACE
BASED INSTABILITY NOSING UP THROUGH THE ST. LOUIS AREA WITH LATEST
SHORT TERM GUIDANCE KEEPING SURFACE BASED INSTABILITY TO THE SOUTH.
RECENT RUC SOUNDING FOR PONTIAC ALSO SHOWS AT LEAST A MINIMAL
INVERSION REMAINING IN PLACE DESPITE THE WARM SECTOR MOVING IN. SO
SEVERE WIND THREAT IS PRETTY MINIMAL BUT WITH LOW LEVEL WINDS OF 50
KT BY 2000 FT OR SO STILL HAVE CONCERNS FOR SOME GUSTS MAKING IT TO
THE SURFACE IF CONVECTION CAN MAINTAIN ITSELF.
SHOWERS/THUNDERSTORMS SHOULD QUICKLY WRAP UP AS THE DRY BOUNDARY
CROSSES THE AREA IN THE 12-15Z TIME FRAME...BRINGING IN LOWER
DEW POINT AIR. WINDS WILL TURN SOUTHWESTERLY AS THE FRONT PASSES WITH
SPEEDS INCREASING AS THE PRESSURE GRADIENT INCREASES AND MIXING WILL
FURTHER BE AIDED BY THE PRESENCE OF THE DRY PUSH OF AIR. THE
WINDIEST PERIOD WILL LIKELY BE THIS AFTERNOON AS A LOW LEVEL SPEED
MAX MOVES ACROSS THE AREA ON THE SOUTHERN FLANK OF THE TROUGH WHICH
ALSO COINCIDES WITH LOWEST TROPOPAUSE HEIGHTS AND THE ARRIVAL OF
COLD ADVECTION. WITH THE CORE OF STRONGEST H92 WINDS IN THE 40-45 KT
RANGE SPREADING INTO THE SOUTHERN CWA WILL GO AHEAD WITH A WIND
ADVISORY GENERALLY ALONG AND SOUTH OF INTERSTATE 80 FROM MID MORNING
INTO EARLY EVENING. THIS WILL SUPPORT GUSTS TO 50 MPH AT TIMES. DO
HAVE A CONCERN FOR HIGH WIND WARNING CRITERIA TO BE MET AS WELL IN
THE FAR SOUTH IF MIXING CAN DEEPEN ENOUGH. MIXING TO H85 WHERE WINDS
WILL BE 50 KT OR A LITTLE BETTER IS A POSSIBILITY GIVEN THE ABOVE
FACTORS SO THIS WILL NEED TO BE MONITORED IN THE SHORT TERM.
TEMPS...WITH THE WARM FRONT LIFTING INTO THE AREA THIS MORNING TEMPS
WILL INCREASE FROM SOUTH TO NORTH AND LIKELY PEAK DURING THE MID TO
LATE MORNING BEFORE COLD ADVECTION ARRIVES. FAIRLY DECENT BUST
POTENTIAL EXISTS WITH THE COMPLEX SURFACE PATTERN IN PLACE. HAVE
SLOWED THE WARMING BASED ON LATEST TRENDS WHICH ALSO SEEM TO SUPPORT
THE NORTHWARD EXPANSE OF THE WARMEST AIR BEING LIMITED. WILL HOLD
HIGHS IN THE NORTHWEST TO THE MID TO UPPER 40S WITH MID TO UPPER 50S
SOUTH OF A CHICAGO TO LASALLE LINE AND LOW TO MID 60S SOUTH OF A
VALPARAISO TO PONTIAC LINE. THE HIGHS WILL BE A BALANCE OF HOW
QUICKLY THE WARM SECTOR ARRIVES AND HOW FAR NORTH AND WEST IT CAN
EXPAND...AND DEPTH OF MIXING THIS MORNING BEFORE COOLER MID LEVEL
AIR ARRIVES EARLY THIS AFTERNOON. HAVE GOOD CONFIDENCE IN THE TRENDS
BUT A FAIR AMOUNT LESS IN THE SPECIFIC VALUES. TEMPS WILL BEGIN TO
FALL IN THE WEST BUT WILL PROBABLY BE A GRADUAL COOLING GIVEN THAT
THE LOW/MID LEVEL TEMP GRADIENT IS NOT IMPRESSIVELY SHARP...AT LEAST
THROUGH MID AFTERNOON. WILL CARRY A COOLING TREND BUT THE SPEED OF
THE COOLING MAY NEED SOME ADJUSTING.
THE CENTER OF THE UPPER LOW WILL PASS NORTH OF THE AREA LATE THIS
AFTERNOON AND EARLY THIS AFTERNOON. THIS WILL BRING A PUSH OF
FORCING BACK TO THE AREA IN ADDITION TO A RETURN OF DEEPER MOISTURE.
IT WILL ALSO PROVIDE A STRONGER PUSH OF COLD AIR. THIS MAY ACT IN
CONJUNCTION WITH NORMAL DIURNAL COOLING TO PROVIDE A FASTER TEMP
DROP LATE THIS AFTERNOON INTO EARLY THIS EVENING. PRECIP CHANCES
WILL RETURN TO MAINLY THE NORTHERN HALF OF THE AREA FROM I-80 NORTH
DURING THE MID/LATE AFTERNOON. MIXED PRECIP IS EXPECTED...WITH
NORTHWEST AREAS PROBABLY SEEING A RAIN SNOW MIX..POSSIBLY WITH SOME
SLEET AS WELL...CHANGING OVER TO SNOW. GOING FURTHER SOUTH AND EAST
RAIN WILL PROBABLY OCCUR AT THE START THEN TRANSITION TO A RAIN/SNOW
MIX BEFORE CHANGING TO ALL SNOW WITH WHATEVER PRECIP IS LEFT DURING
THE EVENING. THE GREATEST PRECIP COVERAGE WILL BE NORTH OF I-88 WITH
LESS EXPECTED TO THE SOUTH AND PROBABLY LITTLE IF ANY SOUTH OF I-80.
HOWEVER...RECENT MODEL TRENDS HAVE BEEN FURTHER SOUTH WITH THE
RETURN OF THE MOISTURE SO A SOUTHWARD EXPANSION OF POPS MAY BE
NEEDED FOR THE LATE AFTERNOON. THE BULK OF THE ENERGY WILL BE OFF TO
THE EAST BY MID/LATE EVENING BUT CYCLONIC FLOW WILL PROBABLY KEEP
FLURRIES GOING INTO THE OVERNIGHT. BREEZY WEST WINDS WILL CONTINUE
THROUGH THE NIGHT BUT BE MUCH LOWER IN SPEED THAN DURING THE
AFTERNOON. OVERNIGHT LOWS WILL RANGE FROM THE UPPER 20S NORTH TO
LOWER 30S SOUTH.
THURSDAY THROUGH SATURDAY...A BIT OF A BREAK WILL ARRIVE THURSDAY AS
HIGH PRESSURE AND THE UPPER RIDGING CURRENTLY OVER THE ROCKIES
DRIFTS ACROSS THE AREA. THE HIGH IS NOT THAT STRONG AND FOCUSED TO
THE SOUTH SO A WEST BREEZE WILL CONTINUE WHICH WILL HELP MIXING. MID
LEVEL WARM ADVECTION WILL BE UNDERWAY BY AFTERNOON WITH H85 TEMPS
EXPECTED TO BE IN THE 0 TO +4 C RANGE BY EVENING. IT DOESN/T LOOK
LIKE THE MOST IDEAL SET UP FOR MAXIMUM WARMING...ESPECIALLY SINCE
THE THE WARMEST AIR ALOFT ARRIVES LATER IN THE DAY. EXPECT THAT
HIGHS SHOULD WARM INTO THE LOW TO MID 40S NORTH TO NEAR 50 SOUTH. IT
IS POSSIBLE THAT A LATE DAY RALLY MAY ALLOW TEMPS TO WARM AN
ADDITIONAL COUPLE DEGREES. THE UPPER TROUGH CURRENTLY MOVING OVER
THE WEST COAST WILL BE SPREADING ACROSS THE ROCKIES AND INTO THE
HIGH PLAINS WHICH WILL TRIGGER SURFACE LOW DEVELOPMENT ACROSS
OKLAHOMA FRIDAY MORNING. A SHORTWAVE IS EXPECTED TO ZIP NORTHWARD UP
THE EASTERN PERIPHERY OF THE LONGER WAVE TROUGH LATE THURSDAY NIGHT
AND ENHANCE WARM ADVECTION WHICH MAY BE SUFFICIENT TO BRING SOME
LIGHT PRECIP ACROSS THE NORTHWEST CWA INTO EARLY FRIDAY.
THEN...ANOTHER SHORTWAVE IS EXPECTED TO WORK NORTHEASTWARD BEHIND IT
AND PUSH THE DEVELOPING SURFACE LOW NORTHEASTWARD INTO FRIDAY
EVENING. GFS/ECMWF/UKMET/GEM IN DECENT AGREEMENT ON TAKING THE LOW
ACROSS NORTH CENTRAL INDIANA WHILE THE NAM IS A BIT FURTHER WEST
TAKING THE LOW ACROSS THE IL/IN BORDER NEAR GARY. THE BULK OF THE
PRECIP LOOKS TO OCCUR DURING THE AFTERNOON AND EARLY EVENING FRIDAY.
MOST OF IT WILL FALL AS RAIN BUT COLDER AIR WORKING EASTWARD WITH
THE UPPER TROUGH WILL MOVE INTO THE FAR NORTHWEST DURING THE LATE
AFTERNOON LIKELY RESULTING IN A RAIN/SNOW MIX. FAR EASTERN AREAS MAY
SEE SOME EMBEDDED THUNDERSTORMS AS WELL. THE LOW QUICKLY EXITS TO
THE NORTHEAST FRIDAY EVENING WITH COLD ADVECTION ACROSS THE AREA.
ANOTHER TROUGH AXIS MOVES THROUGH THE LONG WAVE AND ACROSS THE AREA
SATURDAY MORNING BUT PRECIP CHANCES LOOK PRETTY MINOR AT THE MOMENT.
TEMPS FRIDAY WILL RANGE FROM THE MID/UPPER 40S NORTHWEST...THOUGH
COOLING LATE...TO THE MID OR UPPER 50S SOUTHEAST WHILE HIGHS
SATURDAY WILL RANGE FROM THE UPPER 30S TO LOWER 40S.
SUNDAY THROUGH TUESDAY...THERE IS GENERAL AGREEMENT IN A LONG WAVE
TROUGH EAST AND A BIG RIDGE WEST FROM LATE IN THE WEEKEND INTO EARLY
NEXT WEEK. SUNDAY MAY SEE PRECIP CHANCES WITH INDICATIONS OF A WAVE
TRAVERSING THE MAIN TROUGH. THINGS BEGIN TO SHIFT MONDAY AND TUESDAY
WITH RIDGING APPROACHING OR REACHING THE LOCAL AREA RESULTING IN A
WARM UP...BUT IT IS NOT CLEAR HOW QUICKLY THIS WILL ARRIVE.
MDB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 12Z...
* ENDING OF RAIN AROUND 12Z.
* IFR CONDITIONS PERSISTING INTO EARLY MORNING.
* LLWS PERSISTING THROUGH LATE MORNING.
* MODERATE SE WINDS VEERING TO S EARLY THIS MORNING AND STRONG AND
VERY GUSTY FROM SW BY MID MORNING.
* RETURN OF MVFR CEILINGS BY EARLY EVENING WITH OCNL MVFR
VISIBILITIES IN -SHSN THROUGH LATE TONIGHT.
TRS
//DISCUSSION...UPDATED 12Z...
RAIN HAS MOVED NE AND ENDED DURING THE PREDAWN AS STRONG MID AND
UPPER DRYING SPREAD INTO THE AREA WITH THE CORE OF A 135KT JET
MAX CROSSING THE MID MS VALLEY. IFR/LIFR PREVAILS ACROSS THE LOCAL
AREA AS THE SURFACE WARM FRONT IS STILL S OF THE TERMINALS...FROM
NE IL SOUTHEASTWARD TO CENTRAL IND AT 11Z.
ANTICIPATE QUICK IMPROVEMENT TO VFR DURING THE EARLY MORNING AS
THE WARM FRONT LIFTS N OF MDW AND ORD. WARM FRONTAL PASSAGE TO
RESULT IN THE WINDS VEERING FROM SE TO S WHILE STRENGTHENING AND
BECOMING QUITE GUSTY FROM THE WSW AFTER THE SYSTEM/S COLD FRONT
MOVES QUICKLY ACROSS THE AREA THIS MORNING.
METARS FROM SITES OF THE WARM FROM SHOW WIDESPREAD 20-25KT GUSTS
AND LOCAL 25-30KT GUSTS. AMDAR DATA FROM EARLY MORNING FLIGHT
INTO AND OUT OF RFD AND ORD SHOW WINDS QUICKLY VEER TO OUT OF THE
SW WITH HEIGHT...AND REACH 50KT WITHIN 3K FT OF THE GROUND...
WHICH IS THE TOP OF THE LOW LEVEL INVERSION IS LOCATED N OF THE
WARM FRONT. RAPID CLEARING OUT OF CLOUDS AS THE WARM FRONT MOVES
N WILL ALLOW GOOD SURFACE HEATING WITH GOOD OVERTURNING IN THE
BOUNDARY LAYER EFFICIENT TRANSFER OF MOMENTUM OF STRONG WINDS
ALOFT DOWN TO THE GROUND AND GUSTS 35-40KT LIKELY BY LATE
MORNING.
THE UPPER LOW CURRENTLY OVER THE EXTREME NW CORNER OF IA WILL MOVE
NORTHEASTWARD TO OVER CENTRAL WI BY LATE AFTERNOON...AND THE E TO
THE CENTRAL GREAT LAKES BY 06Z WED. AS THE SYSTEM MOVES FROM WI
INTO THE WESTERN GREAT LAKES LATE THIS AFTERNOON AND EARLY THIS
EVENING LOW LEVEL MOISTURE AND STEEP LOW LEVEL LAPSE RATES WRAP S
AND SE AROUND IT. THIS WILL BRING MVFR CLOUDS AND SOME -SN/-SHSN
TO THE AREA FOR THE EVENING.
WITH THE CENTER OF THE SYSTEM MOVING FARTHER E ACROSS THE GREAT
LAKES LATER THIS EVENING AND OVERNIGHT THE PRESSURE GRADIENT OVER
THE LOCAL AREA WILL LESSEN SIGNIFICANTLY...WITH WINDS DROPPING OFF
DURING THE EVENING AND ESPECIALLY OVERNIGHT.
TRS
//ORD AND MDW CONFIDENCE...UPDATED 12Z...
* HIGH CONFIDENCE IN LLWS EARLY-MID MORNING.
* HIGH CONFIDENCE IN CIG/VIS/PCPN TRENDS EARLY THIS MORNING INTO
THIS AFTERNOON.
* HIGH CONFIDENCE IN WIND TRENDS...WITH MEDIUM CONFIDENCE IN GUST
SPEEDS LATE MORNING THROUGH AFTERNOON.
* HIGH CONFIDENCE IN MVFR CIGS FROM EARLY EVENING THROUGH TONIGHT.
* MEDIUM CONFIDENCE IN PERIOD OF MVFR VISIBILITIES THIS EVENING IN
-SHSN.
TRS
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT...VFR. WX NIL.
FRIDAY...MVFR LOWERING TO IFR IN RA. CHANCE OF TS LATER IN THE
DAY. IFR CIGS IMPROVE TO MVFR BY EVENING. CHANCE OF -SN DURING
THE NIGHT.
SATURDAY...VFR. WX NIL
SUNDAY...VFR. CHANCE OF -SN.
MONDAY...VFR. WX NIL.
TUESDAY...VFR. WX NIL.
TRS
&&
.MARINE...
303 AM CST
A STRONG AREA OF LOW PRESSURE OVER THE MID-MISSOURI VALLEY EARLY
THIS MORNING WILL TRACK NORTHEAST ACROSS LAKE MICHIGAN TONIGHT.
AHEAD OF THE LOW...A WARM FRONT WILL LIFT NORTH ACROSS THE LAKE WITH
STRONG SOUTHEASTERLY WINDS AHEAD OF THE FRONT AND A FEW
THUNDERSTORMS...MAINLY ACROSS SOUTHERN LAKE MICHIGAN. EXPECT GALE
FORCE WINDS TO OVERSPREAD THE LAKE BY EARLY THIS MORNING. WINDS MAY
SLACKEN SOMEWHAT IN THE FRONTAL TROUGH AS THE WARM FRONT LIFTS
ACROSS THE LAKE...BUT STRONG SOUTHWESTERLY WINDS WILL FILL IN BEHIND
THE FRONT AS A STRONG LOW-LEVEL JET DEVELOPS JUST TO THE SOUTH OF
LAKE MICHIGAN. BY THE EARLY MORNING HOURS THURSDAY...THE LOW WILL
BEGIN TO WEAKEN AS IT MOVES EAST OF LAKE MICHIGAN WITH A WEAK RIDGE
OF HIGH PRESSURE TRANSITING ACROSS THE LAKE THURSDAY AFTERNOON
ALLOWING WINDS TO DIMINISH. ANOTHER LOW PRESSURE SYSTEM WILL
COALESCE OVER THE SOUTHERN PLAINS EARLY FRIDAY...THEN MOVE NORTHEAST
AND DEEPEN AS IT PUSHES ACROSS LAKE MICHIGAN FRIDAY EVENING. GALE
FORCE WINDS WILL BE POSSIBLE AGAIN BEHIND THIS LOW ON SATURDAY. BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WIND ADVISORY...ILZ019-ILZ020-ILZ021-ILZ022-ILZ023-ILZ032-ILZ033-
ILZ039 UNTIL 6 PM WEDNESDAY.
IN...WIND ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL 6 PM
WEDNESDAY.
LM...GALE WARNING...LMZ080-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ872-
LMZ874-LMZ876-LMZ878 UNTIL 9 PM WEDNESDAY.
GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
LMZ669-LMZ868-LMZ870 UNTIL 3 PM WEDNESDAY.
GALE WARNING...NEARSHORE WATERS UNTIL 9
PM WEDNESDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 8 AM WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
601 AM CST WED FEB 29 2012
.DISCUSSION...
340 AM CST
A RATHER COMPLEX PATTERN LEADS TO A COMPLICATED SHORT TERM PERIOD OF
THE FORECAST WITH SEVERAL CONCERNS INCLUDING THUNDER POTENTIAL NEXT
FEW HOURS...WIND GUSTS THROUGH THE AFTERNOON...TEMP TRENDS...AND
ADDITIONAL PRECIP CHANCES/TYPE INTO THE EVENING. EARLY MORNING WATER
VAPOR IMAGERY SHOWS THE CLOSED UPPER LOW RESPONSIBLE FOR ALL OF THE
ABOVE SPINNING OVER NORTHWEST IOWA AND HEADING EAST. BEHIND IT...LOW
AMPLITUDE RIDGING IS WORKING ACROSS THE CENTRAL AND NORTHERN ROCKIES
WITH ANOTHER CLOSED UPPER LOW COMING ONSHORE OVER THE PACIFIC
NORTHWEST. THIS LOW WILL BE SIGNIFICANT FOR THE LOCAL AREA FRIDAY.
AT THE SURFACE...LOW PRESSURE CONTINUES SPIN OVER FAR NORTHERN IOWA
AND FAR SOUTHERN MINNESOTA AND IS BEGINNING TO OCCLUDE...WITH A WARM
FRONT EXTENDING SOUTHEASTWARD AND JUST NOW MOVING NORTHWARD INTO THE
EXTREME SOUTHERN CWA...AND A COOL FRONT CROSSING THE MISSISSIPPI
RIVER INTO WEST CENTRAL AND SOUTHWEST ILLINOIS WITH A STRONGER COLD
FRONT TRAILING IT TO THE WEST. BROAD AREA OF WARM ADVECTION SHOWERS
AND THUNDERSTORMS IS EXITING TO THE NORTHEAST WHILE ANOTHER ROUND OF
SHOWERS AND EMBEDDED THUNDERSTORMS LIFTS NORTHEASTWARD AHEAD OF THE
WARM FRONT/OCCLUSION WITH AN EXTENSION SOUTHWARD DOWN THE INITIAL
COOL FRONT.
TODAY AND TONIGHT...THE WARM FRONT WILL CONTINUE TO LIFT
NORTHEASTWARD ACROSS THE AREA OVER THE NEXT FEW HOURS WHILE THE
INITIAL COOL FRONT...WHICH IS REALLY MORE OF MARKER FOR THE LEADING
EDGE OF A DRIER AIR MASS...SPREADS EASTWARD. THE WARM/MOIST SECTOR
BETWEEN THE TWO IS RATHER COMPACT AND IS JUST NOW MOVING INTO THE
FAR SOUTHERN CWA AT 09Z. IN TERMS OF THUNDERSTORMS...LATEST RADAR
TRENDS AND SHORT TERM GUIDANCE BRING THE NEXT BAND OF
SHOWERS/EMBEDDED THUNDER ACROSS THE AREA BETWEEN NOW AND ABOUT 12Z
AS THE WARM FRONT LIFTS NORTHWARD. LAST FEW RADAR SCANS SHOW SOME
NEW DEVELOPMENT ON THE SOUTHERN END OF THE ORIGINAL LINE FROM
GALESBURG TO MACOMB TO QUINCY WHICH APPEARS TO BE RIGHT ALONG THE
DRY BOUNDARY. ANOTHER LINE OF CONVECTION IS ONGOING FROM BLOOMINGTON
SOUTHWARD AND WAS INITIALLY TIED TO THE FRONT BUT NOW APPEARS TO BE
OUT AHEAD OF IT. THIS NEW DEVELOPMENT IS OF SOME CONCERN IN THAT IT
WILL LIKELY CROSS THE SOUTHERN CWA WHICH WILL LIKELY BE IN THE WARM
SECTOR IN THE NEXT FEW HOURS. LATEST SPC MESOANALYSIS SHOWS SURFACE
BASED INSTABILITY NOSING UP THROUGH THE ST. LOUIS AREA WITH LATEST
SHORT TERM GUIDANCE KEEPING SURFACE BASED INSTABILITY TO THE SOUTH.
RECENT RUC SOUNDING FOR PONTIAC ALSO SHOWS AT LEAST A MINIMAL
INVERSION REMAINING IN PLACE DESPITE THE WARM SECTOR MOVING IN. SO
SEVERE WIND THREAT IS PRETTY MINIMAL BUT WITH LOW LEVEL WINDS OF 50
KT BY 2000 FT OR SO STILL HAVE CONCERNS FOR SOME GUSTS MAKING IT TO
THE SURFACE IF CONVECTION CAN MAINTAIN ITSELF.
SHOWERS/THUNDERSTORMS SHOULD QUICKLY WRAP UP AS THE DRY BOUNDARY
CROSSES THE AREA IN THE 12-15Z TIME FRAME...BRINGING IN LOWER
DEW POINT AIR. WINDS WILL TURN SOUTHWESTERLY AS THE FRONT PASSES WITH
SPEEDS INCREASING AS THE PRESSURE GRADIENT INCREASES AND MIXING WILL
FURTHER BE AIDED BY THE PRESENCE OF THE DRY PUSH OF AIR. THE
WINDIEST PERIOD WILL LIKELY BE THIS AFTERNOON AS A LOW LEVEL SPEED
MAX MOVES ACROSS THE AREA ON THE SOUTHERN FLANK OF THE TROUGH WHICH
ALSO COINCIDES WITH LOWEST TROPOPAUSE HEIGHTS AND THE ARRIVAL OF
COLD ADVECTION. WITH THE CORE OF STRONGEST H92 WINDS IN THE 40-45 KT
RANGE SPREADING INTO THE SOUTHERN CWA WILL GO AHEAD WITH A WIND
ADVISORY GENERALLY ALONG AND SOUTH OF INTERSTATE 80 FROM MID MORNING
INTO EARLY EVENING. THIS WILL SUPPORT GUSTS TO 50 MPH AT TIMES. DO
HAVE A CONCERN FOR HIGH WIND WARNING CRITERIA TO BE MET AS WELL IN
THE FAR SOUTH IF MIXING CAN DEEPEN ENOUGH. MIXING TO H85 WHERE WINDS
WILL BE 50 KT OR A LITTLE BETTER IS A POSSIBILITY GIVEN THE ABOVE
FACTORS SO THIS WILL NEED TO BE MONITORED IN THE SHORT TERM.
TEMPS...WITH THE WARM FRONT LIFTING INTO THE AREA THIS MORNING TEMPS
WILL INCREASE FROM SOUTH TO NORTH AND LIKELY PEAK DURING THE MID TO
LATE MORNING BEFORE COLD ADVECTION ARRIVES. FAIRLY DECENT BUST
POTENTIAL EXISTS WITH THE COMPLEX SURFACE PATTERN IN PLACE. HAVE
SLOWED THE WARMING BASED ON LATEST TRENDS WHICH ALSO SEEM TO SUPPORT
THE NORTHWARD EXPANSE OF THE WARMEST AIR BEING LIMITED. WILL HOLD
HIGHS IN THE NORTHWEST TO THE MID TO UPPER 40S WITH MID TO UPPER 50S
SOUTH OF A CHICAGO TO LASALLE LINE AND LOW TO MID 60S SOUTH OF A
VALPARAISO TO PONTIAC LINE. THE HIGHS WILL BE A BALANCE OF HOW
QUICKLY THE WARM SECTOR ARRIVES AND HOW FAR NORTH AND WEST IT CAN
EXPAND...AND DEPTH OF MIXING THIS MORNING BEFORE COOLER MID LEVEL
AIR ARRIVES EARLY THIS AFTERNOON. HAVE GOOD CONFIDENCE IN THE TRENDS
BUT A FAIR AMOUNT LESS IN THE SPECIFIC VALUES. TEMPS WILL BEGIN TO
FALL IN THE WEST BUT WILL PROBABLY BE A GRADUAL COOLING GIVEN THAT
THE LOW/MID LEVEL TEMP GRADIENT IS NOT IMPRESSIVELY SHARP...AT LEAST
THROUGH MID AFTERNOON. WILL CARRY A COOLING TREND BUT THE SPEED OF
THE COOLING MAY NEED SOME ADJUSTING.
THE CENTER OF THE UPPER LOW WILL PASS NORTH OF THE AREA LATE THIS
AFTERNOON AND EARLY THIS AFTERNOON. THIS WILL BRING A PUSH OF
FORCING BACK TO THE AREA IN ADDITION TO A RETURN OF DEEPER MOISTURE.
IT WILL ALSO PROVIDE A STRONGER PUSH OF COLD AIR. THIS MAY ACT IN
CONJUNCTION WITH NORMAL DIURNAL COOLING TO PROVIDE A FASTER TEMP
DROP LATE THIS AFTERNOON INTO EARLY THIS EVENING. PRECIP CHANCES
WILL RETURN TO MAINLY THE NORTHERN HALF OF THE AREA FROM I-80 NORTH
DURING THE MID/LATE AFTERNOON. MIXED PRECIP IS EXPECTED...WITH
NORTHWEST AREAS PROBABLY SEEING A RAIN SNOW MIX..POSSIBLY WITH SOME
SLEET AS WELL...CHANGING OVER TO SNOW. GOING FURTHER SOUTH AND EAST
RAIN WILL PROBABLY OCCUR AT THE START THEN TRANSITION TO A RAIN/SNOW
MIX BEFORE CHANGING TO ALL SNOW WITH WHATEVER PRECIP IS LEFT DURING
THE EVENING. THE GREATEST PRECIP COVERAGE WILL BE NORTH OF I-88 WITH
LESS EXPECTED TO THE SOUTH AND PROBABLY LITTLE IF ANY SOUTH OF I-80.
HOWEVER...RECENT MODEL TRENDS HAVE BEEN FURTHER SOUTH WITH THE
RETURN OF THE MOISTURE SO A SOUTHWARD EXPANSION OF POPS MAY BE
NEEDED FOR THE LATE AFTERNOON. THE BULK OF THE ENERGY WILL BE OFF TO
THE EAST BY MID/LATE EVENING BUT CYCLONIC FLOW WILL PROBABLY KEEP
FLURRIES GOING INTO THE OVERNIGHT. BREEZY WEST WINDS WILL CONTINUE
THROUGH THE NIGHT BUT BE MUCH LOWER IN SPEED THAN DURING THE
AFTERNOON. OVERNIGHT LOWS WILL RANGE FROM THE UPPER 20S NORTH TO
LOWER 30S SOUTH.
THURSDAY THROUGH SATURDAY...A BIT OF A BREAK WILL ARRIVE THURSDAY AS
HIGH PRESSURE AND THE UPPER RIDGING CURRENTLY OVER THE ROCKIES
DRIFTS ACROSS THE AREA. THE HIGH IS NOT THAT STRONG AND FOCUSED TO
THE SOUTH SO A WEST BREEZE WILL CONTINUE WHICH WILL HELP MIXING. MID
LEVEL WARM ADVECTION WILL BE UNDERWAY BY AFTERNOON WITH H85 TEMPS
EXPECTED TO BE IN THE 0 TO +4 C RANGE BY EVENING. IT DOESN/T LOOK
LIKE THE MOST IDEAL SET UP FOR MAXIMUM WARMING...ESPECIALLY SINCE
THE THE WARMEST AIR ALOFT ARRIVES LATER IN THE DAY. EXPECT THAT
HIGHS SHOULD WARM INTO THE LOW TO MID 40S NORTH TO NEAR 50 SOUTH. IT
IS POSSIBLE THAT A LATE DAY RALLY MAY ALLOW TEMPS TO WARM AN
ADDITIONAL COUPLE DEGREES. THE UPPER TROUGH CURRENTLY MOVING OVER
THE WEST COAST WILL BE SPREADING ACROSS THE ROCKIES AND INTO THE
HIGH PLAINS WHICH WILL TRIGGER SURFACE LOW DEVELOPMENT ACROSS
OKLAHOMA FRIDAY MORNING. A SHORTWAVE IS EXPECTED TO ZIP NORTHWARD UP
THE EASTERN PERIPHERY OF THE LONGER WAVE TROUGH LATE THURSDAY NIGHT
AND ENHANCE WARM ADVECTION WHICH MAY BE SUFFICIENT TO BRING SOME
LIGHT PRECIP ACROSS THE NORTHWEST CWA INTO EARLY FRIDAY.
THEN...ANOTHER SHORTWAVE IS EXPECTED TO WORK NORTHEASTWARD BEHIND IT
AND PUSH THE DEVELOPING SURFACE LOW NORTHEASTWARD INTO FRIDAY
EVENING. GFS/ECMWF/UKMET/GEM IN DECENT AGREEMENT ON TAKING THE LOW
ACROSS NORTH CENTRAL INDIANA WHILE THE NAM IS A BIT FURTHER WEST
TAKING THE LOW ACROSS THE IL/IN BORDER NEAR GARY. THE BULK OF THE
PRECIP LOOKS TO OCCUR DURING THE AFTERNOON AND EARLY EVENING FRIDAY.
MOST OF IT WILL FALL AS RAIN BUT COLDER AIR WORKING EASTWARD WITH
THE UPPER TROUGH WILL MOVE INTO THE FAR NORTHWEST DURING THE LATE
AFTERNOON LIKELY RESULTING IN A RAIN/SNOW MIX. FAR EASTERN AREAS MAY
SEE SOME EMBEDDED THUNDERSTORMS AS WELL. THE LOW QUICKLY EXITS TO
THE NORTHEAST FRIDAY EVENING WITH COLD ADVECTION ACROSS THE AREA.
ANOTHER TROUGH AXIS MOVES THROUGH THE LONG WAVE AND ACROSS THE AREA
SATURDAY MORNING BUT PRECIP CHANCES LOOK PRETTY MINOR AT THE MOMENT.
TEMPS FRIDAY WILL RANGE FROM THE MID/UPPER 40S NORTHWEST...THOUGH
COOLING LATE...TO THE MID OR UPPER 50S SOUTHEAST WHILE HIGHS
SATURDAY WILL RANGE FROM THE UPPER 30S TO LOWER 40S.
SUNDAY THROUGH TUESDAY...THERE IS GENERAL AGREEMENT IN A LONG WAVE
TROUGH EAST AND A BIG RIDGE WEST FROM LATE IN THE WEEKEND INTO EARLY
NEXT WEEK. SUNDAY MAY SEE PRECIP CHANCES WITH INDICATIONS OF A WAVE
TRAVERSING THE MAIN TROUGH. THINGS BEGIN TO SHIFT MONDAY AND TUESDAY
WITH RIDGING APPROACHING OR REACHING THE LOCAL AREA RESULTING IN A
WARM UP...BUT IT IS NOT CLEAR HOW QUICKLY THIS WILL ARRIVE.
MDB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 12Z...
* ENDING OF RAIN AROUND 12Z.
* IFR CONDITIONS PERSISTING INTO EARLY MORNING.
* LLWS PERSISTING THROUGH LATE MORNING.
* MODERATE SE WINDS VEERING TO S EARLY THIS MORNING AND STRONG AND
VERY GUSTY FROM SW BY MID MORNING.
* RETURN OF MVFR CEILINGS BY EARLY EVENING WITH OCNL MVFR
VISIBILITIES IN -SHSN THROUGH LATE TONIGHT.
TRS
//DISCUSSION...UPDATED 12Z...
RAIN HAS MOVED NE AND ENDED DURING THE PREDAWN AS STRONG MID AND
UPPER DRYING SPREAD INTO THE AREA WITH THE CORE OF A 135KT JET
MAX CROSSING THE MID MS VALLEY. IFR/LIFR PREVAILS ACROSS THE LOCAL
AREA AS THE SURFACE WARM FRONT IS STILL S OF THE TERMINALS...FROM
NE IL SOUTHEASTWARD TO CENTRAL IND AT 11Z.
ANTICIPATE QUICK IMPROVEMENT TO VFR DURING THE EARLY MORNING AS
THE WARM FRONT LIFTS N OF MDW AND ORD. WARM FRONTAL PASSAGE TO
RESULT IN THE WINDS VEERING FROM SE TO S WHILE STRENGTHENING AND
BECOMING QUITE GUSTY FROM THE WSW AFTER THE SYSTEM/S COLD FRONT
MOVES QUICKLY ACROSS THE AREA THIS MORNING.
METARS FROM SITES OF THE WARM FROM SHOW WIDESPREAD 20-25KT GUSTS
AND LOCAL 25-30KT GUSTS. AMDAR DATA FROM EARLY MORNING FLIGHT
INTO AND OUT OF RFD AND ORD SHOW WINDS QUICKLY VEER TO OUT OF THE
SW WITH HEIGHT...AND REACH 50KT WITHIN 3K FT OF THE GROUND...
WHICH IS THE TOP OF THE LOW LEVEL INVERSION IS LOCATED N OF THE
WARM FRONT. RAPID CLEARING OUT OF CLOUDS AS THE WARM FRONT MOVES
N WILL ALLOW GOOD SURFACE HEATING WITH GOOD OVERTURNING IN THE
BOUNDARY LAYER EFFICIENT TRANSFER OF MOMENTUM OF STRONG WINDS
ALOFT DOWN TO THE GROUND AND GUSTS 35-40KT LIKELY BY LATE
MORNING.
THE UPPER LOW CURRENTLY OVER THE EXTREME NW CORNER OF IA WILL MOVE
NORTHEASTWARD TO OVER CENTRAL WI BY LATE AFTERNOON...AND THE E TO
THE CENTRAL GREAT LAKES BY 06Z WED. AS THE SYSTEM MOVES FROM WI
INTO THE WESTERN GREAT LAKES LATE THIS AFTERNOON AND EARLY THIS
EVENING LOW LEVEL MOISTURE AND STEEP LOW LEVEL LAPSE RATES WRAP S
AND SE AROUND IT. THIS WILL BRING MVFR CLOUDS AND SOME -SN/-SHSN
TO THE AREA FOR THE EVENING.
WITH THE CENTER OF THE SYSTEM MOVING FARTHER E ACROSS THE GREAT
LAKES LATER THIS EVENING AND OVERNIGHT THE PRESSURE GRADIENT OVER
THE LOCAL AREA WILL LESSEN SIGNIFICANTLY...WITH WINDS DROPPING OFF
DURING THE EVENING AND ESPECIALLY OVERNIGHT.
TRS
//ORD AND MDW CONFIDENCE...UPDATED 12Z...
* HIGH CONFIDENCE IN LLWS EARLY-MID MORNING.
* HIGH CONFIDENCE IN CIG/VIS/PCPN TRENDS EARLY THIS MORNING INTO
THIS AFTERNOON.
* HIGH CONFIDENCE IN WIND TRENDS...WITH MEDIUM CONFIDENCE IN GUST
SPEEDS LATE MORNING THROUGH AFTERNOON.
* HIGH CONFIDENCE IN MVFR CIGS FROM EARLY EVENING THROUGH TONIGHT.
* MEDIUM CONFIDENCE IN PERIOD OF MVFR VISIBILITIES THIS EVENING IN
-SHSN.
TRS
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT...VFR. WX NIL.
FRIDAY...MVFR LOWERING TO IFR IN RA. CHANCE OF TS LATER IN THE
DAY. IFR CIGS IMPROVE TO MVFR BY EVENING. CHANCE OF -SN DURING
THE NIGHT.
SATURDAY...VFR. WX NIL
SUNDAY...VFR. CHANCE OF -SN.
MONDAY...VFR. WX NIL.
TUESDAY...VFR. WX NIL.
TRS
&&
.MARINE...
303 AM CST
A STRONG AREA OF LOW PRESSURE OVER THE MID-MISSOURI VALLEY EARLY
THIS MORNING WILL TRACK NORTHEAST ACROSS LAKE MICHIGAN TONIGHT.
AHEAD OF THE LOW...A WARM FRONT WILL LIFT NORTH ACROSS THE LAKE WITH
STRONG SOUTHEASTERLY WINDS AHEAD OF THE FRONT AND A FEW
THUNDERSTORMS...MAINLY ACROSS SOUTHERN LAKE MICHIGAN. EXPECT GALE
FORCE WINDS TO OVERSPREAD THE LAKE BY EARLY THIS MORNING. WINDS MAY
SLACKEN SOMEWHAT IN THE FRONTAL TROUGH AS THE WARM FRONT LIFTS
ACROSS THE LAKE...BUT STRONG SOUTHWESTERLY WINDS WILL FILL IN BEHIND
THE FRONT AS A STRONG LOW-LEVEL JET DEVELOPS JUST TO THE SOUTH OF
LAKE MICHIGAN. BY THE EARLY MORNING HOURS THURSDAY...THE LOW WILL
BEGIN TO WEAKEN AS IT MOVES EAST OF LAKE MICHIGAN WITH A WEAK RIDGE
OF HIGH PRESSURE TRANSITING ACROSS THE LAKE THURSDAY AFTERNOON
ALLOWING WINDS TO DIMINISH. ANOTHER LOW PRESSURE SYSTEM WILL
COALESCE OVER THE SOUTHERN PLAINS EARLY FRIDAY...THEN MOVE NORTHEAST
AND DEEPEN AS IT PUSHES ACROSS LAKE MICHIGAN FRIDAY EVENING. GALE
FORCE WINDS WILL BE POSSIBLE AGAIN BEHIND THIS LOW ON SATURDAY. BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WIND ADVISORY...ILZ019-ILZ020-ILZ021-ILZ022-ILZ023-ILZ032-ILZ033-
ILZ039...9 AM WEDNESDAY TO 6 PM WEDNESDAY.
IN...WIND ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019...9 AM
WEDNESDAY TO 6 PM WEDNESDAY.
LM...GALE WARNING...LMZ080-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ872-
LMZ874-LMZ876-LMZ878 UNTIL 9 PM WEDNESDAY.
GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
LMZ669-LMZ868-LMZ870 UNTIL 3 PM WEDNESDAY.
GALE WARNING...NEARSHORE WATERS UNTIL 9
PM WEDNESDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 8 AM WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
427 AM CST WED FEB 29 2012
.DISCUSSION...
340 AM CST
A RATHER COMPLEX PATTERN LEADS TO A COMPLICATED SHORT TERM PERIOD OF
THE FORECAST WITH SEVERAL CONCERNS INCLUDING THUNDER POTENTIAL NEXT
FEW HOURS...WIND GUSTS THROUGH THE AFTERNOON...TEMP TRENDS...AND
ADDITIONAL PRECIP CHANCES/TYPE INTO THE EVENING. EARLY MORNING WATER
VAPOR IMAGERY SHOWS THE CLOSED UPPER LOW RESPONSIBLE FOR ALL OF THE
ABOVE SPINNING OVER NORTHWEST IOWA AND HEADING EAST. BEHIND IT...LOW
AMPLITUDE RIDGING IS WORKING ACROSS THE CENTRAL AND NORTHERN ROCKIES
WITH ANOTHER CLOSED UPPER LOW COMING ONSHORE OVER THE PACIFIC
NORTHWEST. THIS LOW WILL BE SIGNIFICANT FOR THE LOCAL AREA FRIDAY.
AT THE SURFACE...LOW PRESSURE CONTINUES SPIN OVER FAR NORTHERN IOWA
AND FAR SOUTHERN MINNESOTA AND IS BEGINNING TO OCCLUDE...WITH A WARM
FRONT EXTENDING SOUTHEASTWARD AND JUST NOW MOVING NORTHWARD INTO THE
EXTREME SOUTHERN CWA...AND A COOL FRONT CROSSING THE MISSISSIPPI
RIVER INTO WEST CENTRAL AND SOUTHWEST ILLINOIS WITH A STRONGER COLD
FRONT TRAILING IT TO THE WEST. BROAD AREA OF WARM ADVECTION SHOWERS
AND THUNDERSTORMS IS EXITING TO THE NORTHEAST WHILE ANOTHER ROUND OF
SHOWERS AND EMBEDDED THUNDERSTORMS LIFTS NORTHEASTWARD AHEAD OF THE
WARM FRONT/OCCLUSION WITH AN EXTENSION SOUTHWARD DOWN THE INITIAL
COOL FRONT.
TODAY AND TONIGHT...THE WARM FRONT WILL CONTINUE TO LIFT
NORTHEASTWARD ACROSS THE AREA OVER THE NEXT FEW HOURS WHILE THE
INITIAL COOL FRONT...WHICH IS REALLY MORE OF MARKER FOR THE LEADING
EDGE OF A DRIER AIR MASS...SPREADS EASTWARD. THE WARM/MOIST SECTOR
BETWEEN THE TWO IS RATHER COMPACT AND IS JUST NOW MOVING INTO THE
FAR SOUTHERN CWA AT 09Z. IN TERMS OF THUNDERSTORMS...LATEST RADAR
TRENDS AND SHORT TERM GUIDANCE BRING THE NEXT BAND OF
SHOWERS/EMBEDDED THUNDER ACROSS THE AREA BETWEEN NOW AND ABOUT 12Z
AS THE WARM FRONT LIFTS NORTHWARD. LAST FEW RADAR SCANS SHOW SOME
NEW DEVELOPMENT ON THE SOUTHERN END OF THE ORIGINAL LINE FROM
GALESBURG TO MACOMB TO QUINCY WHICH APPEARS TO BE RIGHT ALONG THE
DRY BOUNDARY. ANOTHER LINE OF CONVECTION IS ONGOING FROM BLOOMINGTON
SOUTHWARD AND WAS INITIALLY TIED TO THE FRONT BUT NOW APPEARS TO BE
OUT AHEAD OF IT. THIS NEW DEVELOPMENT IS OF SOME CONCERN IN THAT IT
WILL LIKELY CROSS THE SOUTHERN CWA WHICH WILL LIKELY BE IN THE WARM
SECTOR IN THE NEXT FEW HOURS. LATEST SPC MESOANALYSIS SHOWS SURFACE
BASED INSTABILITY NOSING UP THROUGH THE ST. LOUIS AREA WITH LATEST
SHORT TERM GUIDANCE KEEPING SURFACE BASED INSTABILITY TO THE SOUTH.
RECENT RUC SOUNDING FOR PONTIAC ALSO SHOWS AT LEAST A MINIMAL
INVERSION REMAINING IN PLACE DESPITE THE WARM SECTOR MOVING IN. SO
SEVERE WIND THREAT IS PRETTY MINIMAL BUT WITH LOW LEVEL WINDS OF 50
KT BY 2000 FT OR SO STILL HAVE CONCERNS FOR SOME GUSTS MAKING IT TO
THE SURFACE IF CONVECTION CAN MAINTAIN ITSELF.
SHOWERS/THUNDERSTORMS SHOULD QUICKLY WRAP UP AS THE DRY BOUNDARY
CROSSES THE AREA IN THE 12-15Z TIME FRAME...BRINGING IN LOWER
DEW POINT AIR. WINDS WILL TURN SOUTHWESTERLY AS THE FRONT PASSES WITH
SPEEDS INCREASING AS THE PRESSURE GRADIENT INCREASES AND MIXING WILL
FURTHER BE AIDED BY THE PRESENCE OF THE DRY PUSH OF AIR. THE
WINDIEST PERIOD WILL LIKELY BE THIS AFTERNOON AS A LOW LEVEL SPEED
MAX MOVES ACROSS THE AREA ON THE SOUTHERN FLANK OF THE TROUGH WHICH
ALSO COINCIDES WITH LOWEST TROPOPAUSE HEIGHTS AND THE ARRIVAL OF
COLD ADVECTION. WITH THE CORE OF STRONGEST H92 WINDS IN THE 40-45 KT
RANGE SPREADING INTO THE SOUTHERN CWA WILL GO AHEAD WITH A WIND
ADVISORY GENERALLY ALONG AND SOUTH OF INTERSTATE 80 FROM MID MORNING
INTO EARLY EVENING. THIS WILL SUPPORT GUSTS TO 50 MPH AT TIMES. DO
HAVE A CONCERN FOR HIGH WIND WARNING CRITERIA TO BE MET AS WELL IN
THE FAR SOUTH IF MIXING CAN DEEPEN ENOUGH. MIXING TO H85 WHERE WINDS
WILL BE 50 KT OR A LITTLE BETTER IS A POSSIBILITY GIVEN THE ABOVE
FACTORS SO THIS WILL NEED TO BE MONITORED IN THE SHORT TERM.
TEMPS...WITH THE WARM FRONT LIFTING INTO THE AREA THIS MORNING TEMPS
WILL INCREASE FROM SOUTH TO NORTH AND LIKELY PEAK DURING THE MID TO
LATE MORNING BEFORE COLD ADVECTION ARRIVES. FAIRLY DECENT BUST
POTENTIAL EXISTS WITH THE COMPLEX SURFACE PATTERN IN PLACE. HAVE
SLOWED THE WARMING BASED ON LATEST TRENDS WHICH ALSO SEEM TO SUPPORT
THE NORTHWARD EXPANSE OF THE WARMEST AIR BEING LIMITED. WILL HOLD
HIGHS IN THE NORTHWEST TO THE MID TO UPPER 40S WITH MID TO UPPER 50S
SOUTH OF A CHICAGO TO LASALLE LINE AND LOW TO MID 60S SOUTH OF A
VALPARAISO TO PONTIAC LINE. THE HIGHS WILL BE A BALANCE OF HOW
QUICKLY THE WARM SECTOR ARRIVES AND HOW FAR NORTH AND WEST IT CAN
EXPAND...AND DEPTH OF MIXING THIS MORNING BEFORE COOLER MID LEVEL
AIR ARRIVES EARLY THIS AFTERNOON. HAVE GOOD CONFIDENCE IN THE TRENDS
BUT A FAIR AMOUNT LESS IN THE SPECIFIC VALUES. TEMPS WILL BEGIN TO
FALL IN THE WEST BUT WILL PROBABLY BE A GRADUAL COOLING GIVEN THAT
THE LOW/MID LEVEL TEMP GRADIENT IS NOT IMPRESSIVELY SHARP...AT LEAST
THROUGH MID AFTERNOON. WILL CARRY A COOLING TREND BUT THE SPEED OF
THE COOLING MAY NEED SOME ADJUSTING.
THE CENTER OF THE UPPER LOW WILL PASS NORTH OF THE AREA LATE THIS
AFTERNOON AND EARLY THIS AFTERNOON. THIS WILL BRING A PUSH OF
FORCING BACK TO THE AREA IN ADDITION TO A RETURN OF DEEPER MOISTURE.
IT WILL ALSO PROVIDE A STRONGER PUSH OF COLD AIR. THIS MAY ACT IN
CONJUNCTION WITH NORMAL DIURNAL COOLING TO PROVIDE A FASTER TEMP
DROP LATE THIS AFTERNOON INTO EARLY THIS EVENING. PRECIP CHANCES
WILL RETURN TO MAINLY THE NORTHERN HALF OF THE AREA FROM I-80 NORTH
DURING THE MID/LATE AFTERNOON. MIXED PRECIP IS EXPECTED...WITH
NORTHWEST AREAS PROBABLY SEEING A RAIN SNOW MIX..POSSIBLY WITH SOME
SLEET AS WELL...CHANGING OVER TO SNOW. GOING FURTHER SOUTH AND EAST
RAIN WILL PROBABLY OCCUR AT THE START THEN TRANSITION TO A RAIN/SNOW
MIX BEFORE CHANGING TO ALL SNOW WITH WHATEVER PRECIP IS LEFT DURING
THE EVENING. THE GREATEST PRECIP COVERAGE WILL BE NORTH OF I-88 WITH
LESS EXPECTED TO THE SOUTH AND PROBABLY LITTLE IF ANY SOUTH OF I-80.
HOWEVER...RECENT MODEL TRENDS HAVE BEEN FURTHER SOUTH WITH THE
RETURN OF THE MOISTURE SO A SOUTHWARD EXPANSION OF POPS MAY BE
NEEDED FOR THE LATE AFTERNOON. THE BULK OF THE ENERGY WILL BE OFF TO
THE EAST BY MID/LATE EVENING BUT CYCLONIC FLOW WILL PROBABLY KEEP
FLURRIES GOING INTO THE OVERNIGHT. BREEZY WEST WINDS WILL CONTINUE
THROUGH THE NIGHT BUT BE MUCH LOWER IN SPEED THAN DURING THE
AFTERNOON. OVERNIGHT LOWS WILL RANGE FROM THE UPPER 20S NORTH TO
LOWER 30S SOUTH.
THURSDAY THROUGH SATURDAY...A BIT OF A BREAK WILL ARRIVE THURSDAY AS
HIGH PRESSURE AND THE UPPER RIDGING CURRENTLY OVER THE ROCKIES
DRIFTS ACROSS THE AREA. THE HIGH IS NOT THAT STRONG AND FOCUSED TO
THE SOUTH SO A WEST BREEZE WILL CONTINUE WHICH WILL HELP MIXING. MID
LEVEL WARM ADVECTION WILL BE UNDERWAY BY AFTERNOON WITH H85 TEMPS
EXPECTED TO BE IN THE 0 TO +4 C RANGE BY EVENING. IT DOESN/T LOOK
LIKE THE MOST IDEAL SET UP FOR MAXIMUM WARMING...ESPECIALLY SINCE
THE THE WARMEST AIR ALOFT ARRIVES LATER IN THE DAY. EXPECT THAT
HIGHS SHOULD WARM INTO THE LOW TO MID 40S NORTH TO NEAR 50 SOUTH. IT
IS POSSIBLE THAT A LATE DAY RALLY MAY ALLOW TEMPS TO WARM AN
ADDITIONAL COUPLE DEGREES. THE UPPER TROUGH CURRENTLY MOVING OVER
THE WEST COAST WILL BE SPREADING ACROSS THE ROCKIES AND INTO THE
HIGH PLAINS WHICH WILL TRIGGER SURFACE LOW DEVELOPMENT ACROSS
OKLAHOMA FRIDAY MORNING. A SHORTWAVE IS EXPECTED TO ZIP NORTHWARD UP
THE EASTERN PERIPHERY OF THE LONGER WAVE TROUGH LATE THURSDAY NIGHT
AND ENHANCE WARM ADVECTION WHICH MAY BE SUFFICIENT TO BRING SOME
LIGHT PRECIP ACROSS THE NORTHWEST CWA INTO EARLY FRIDAY.
THEN...ANOTHER SHORTWAVE IS EXPECTED TO WORK NORTHEASTWARD BEHIND IT
AND PUSH THE DEVELOPING SURFACE LOW NORTHEASTWARD INTO FRIDAY
EVENING. GFS/ECMWF/UKMET/GEM IN DECENT AGREEMENT ON TAKING THE LOW
ACROSS NORTH CENTRAL INDIANA WHILE THE NAM IS A BIT FURTHER WEST
TAKING THE LOW ACROSS THE IL/IN BORDER NEAR GARY. THE BULK OF THE
PRECIP LOOKS TO OCCUR DURING THE AFTERNOON AND EARLY EVENING FRIDAY.
MOST OF IT WILL FALL AS RAIN BUT COLDER AIR WORKING EASTWARD WITH
THE UPPER TROUGH WILL MOVE INTO THE FAR NORTHWEST DURING THE LATE
AFTERNOON LIKELY RESULTING IN A RAIN/SNOW MIX. FAR EASTERN AREAS MAY
SEE SOME EMBEDDED THUNDERSTORMS AS WELL. THE LOW QUICKLY EXITS TO
THE NORTHEAST FRIDAY EVENING WITH COLD ADVECTION ACROSS THE AREA.
ANOTHER TROUGH AXIS MOVES THROUGH THE LONG WAVE AND ACROSS THE AREA
SATURDAY MORNING BUT PRECIP CHANCES LOOK PRETTY MINOR AT THE MOMENT.
TEMPS FRIDAY WILL RANGE FROM THE MID/UPPER 40S NORTHWEST...THOUGH
COOLING LATE...TO THE MID OR UPPER 50S SOUTHEAST WHILE HIGHS
SATURDAY WILL RANGE FROM THE UPPER 30S TO LOWER 40S.
SUNDAY THROUGH TUESDAY...THERE IS GENERAL AGREEMENT IN A LONG WAVE
TROUGH EAST AND A BIG RIDGE WEST FROM LATE IN THE WEEKEND INTO EARLY
NEXT WEEK. SUNDAY MAY SEE PRECIP CHANCES WITH INDICATIONS OF A WAVE
TRAVERSING THE MAIN TROUGH. THINGS BEGIN TO SHIFT MONDAY AND TUESDAY
WITH RIDGING APPROACHING OR REACHING THE LOCAL AREA RESULTING IN A
WARM UP...BUT IT IS NOT CLEAR HOW QUICKLY THIS WILL ARRIVE.
MDB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 10Z...
* ENDING OF RAIN EARLY PREDAWN.
* IFR CONDITIONS PERSISTING INTO EARLY MORNING.
* LLWS PERSISTING THROUGH LATE MORNING.
* MODERATE SE WINDS VEERING TO S EARLY THIS MORNING AND STRONG AND
VERY GUSTY FROM SW BY MID MORNING.
* RETURN OF MVFR CEILINGS BY EARLY EVENING WITH OCNL MVFR
VISIBILITIES IN -SHSN THROUGH LATE TONIGHT.
TRS
//DISCUSSION...UPDATED 06Z...
A VERY SLOPPY WX PICTURE EVOLVING WITH MULTIPLE WX CONCERNS. A LOW
PRESSURE SYSTEM IS DEEPENING OVER THE UPPER MISSOURI VALLEY WILL
TURN EAST TRACK THROUGH SRN MN/WI TOMORROW. THIS SYSTEM IS DRAWING
MOISTURE NWD FROM THE GLFMEX...AND OVERRUNNING AN ASSOCIATED WARM
FRONT EXTENDING THROUGH SRN IOWA TO SRN IL/IN. WIDESPREAD RAIN HAS
OVERSPREAD THE AREA...WITH THE LATEST RADAR IMAGERY SHOWING MORE
CONVECTIVE ELEMENTS AND SCT TS ALONG AND SOUTH OF THE WARM FRONT.
AT ISSUANCE TIME...CONDITIONS WILL BE APPROACHING MVFR LEVELS AND
EXPECT CIGS/VIS TO DROP TO MVFR BY AROUND MIDNIGHT. THERE WILL BE
ENOUGH ELEVATED INSTABILITY TO SUPPORT ISOLD/EMBEDDED TS...BUT
COVERAGE SHOULD BE SPARSE AND HAVE LITTLE CONFIDENCE ON ANY TIMING
OR DURATION OF TS AT THE TERMINALS. SO...WILL CONTINUE TO LIMIT
THE TS MENTION IN THE TAFS TO JUST VCTS AND CB GROUPS. CONFIDENCE
IS HIGHER ON THE OTHER IMPACTS ON SERVICE IN THE POTENTIAL FOR IFR
CONDITIONS AS THE WARM FRONT LIFTS NWRD THROUGH NRN IL EARLY
TOMORROW MORNING. THERE IS ALSO SOME CONCERN IN THE POSSIBILITY OF
STRONGER...MORE LINEAR TS DEVELOPING WITH THE COLD FRONT PASSAGE.
THE SHORT RANGE MODEL GUIDANCE INDICATES THAT THE COLD FRONT
SHOULD QUICKLY PUSH THROUGH THE AREA TOMORROW MORNING BTWN 12-16Z.
THERE ARE INDICATIONS OF THE POTENTIAL FOR INCREASED SURFACE BASED
INSTABILITY AND A WARM SECTOR ENVIRONMENT PUSHING QUICKLY THROUGH
THE AREA BETWEEN THE TIME THAT THE WARM FRONT LIFTS TO THE NORTH
AND THE COLD FRONT SWEEPS EWD ACROSS IL/IN. THIS WOULD PROVIDE A
BRIEF WINDOW OF OPPORTUNITY FOR STRONGER TS TO DEVELOP...BUT
CONFIDENCE IN TIMING IS LOW. FOLLOWING THE PASSAGE OF THE SFC COLD
FRONT...DRY AIR ALOFT WILL OVERRIDE A MOIST LAYER BLW 5KFT...SO A
PERIOD OF DZ WITH IFR CIGS/VIS IS LIKELY THOUGH ARND 18Z. ALSO
FOLLOWING THE FROPA...WINDS WILL VEER SWLY AND QUICKLY STRENGTHEN
THROUGH THE MORNING...WITH GUSTS OF 35KT...OR POSSIBLY
HIGHER...ARE EXPECTED THROUGH THE REMAINDER OF THE AFTERNOON.
BY LATE TOMORROW EVENING...WRAPAROUND MOISTURE AND CYCLONIC FLOW
ALOFT ALONG WILL COOLER AIR FILTERING INTO THE AREA BEHIND THE
EXITING LOW WILL BRING BACK MVFR CIGS AND SOME LIGHT SNOW. WITH
THE COLD CORE UPPER LOW MOVING OVER SRN WI DURG THE
EVENING...THERE MAY BE ENOUGH INSTABILITY FOR SOME HEAVIER SNOW
SHOWERS OR GRAUPEL WITH THE LIGHT SNOW.
KREIN
//ORD AND MDW CONFIDENCE...UPDATED 10Z...
* HIGH CONFIDENCE IN LLWS EARLY-MID MORNING.
* HIGH CONFIDENCE IN CIG/VIS/PCPN TRENDS THIS MORNING INTO
AFTERNOON.
* HIGH CONFIDENCE IN WIND TRENDS...WITH MEDIUM CONFIDENCE IN GUST
SPEEDS LATE MORNING THROUGH AFTERNOON.
TRS
//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...
THURSDAY...VFR. WX NIL.
FRIDAY...MVFR CIGS/VIS. RAIN OR A RAIN/SNOW MIX LIKELY DURING THE
DAY...CHANCE OF LIGHT SNOW AT NIGHT.
SATURDAY...VFR...SLIGHT CHANCE OF LIGHT SNOW OR FLURRIES EARLY...STRONG
GUSTY GUSTY W WINDS IN THE AFTERNOON.
SUNDAY...VFR. SLIGHT CHANCE LIGHT SNOW EARLY.
MONDAY...VFR. WX NIL.
KREIN
&&
.MARINE...
303 AM CST
A STRONG AREA OF LOW PRESSURE OVER THE MID-MISSOURI VALLEY EARLY
THIS MORNING WILL TRACK NORTHEAST ACROSS LAKE MICHIGAN TONIGHT.
AHEAD OF THE LOW...A WARM FRONT WILL LIFT NORTH ACROSS THE LAKE WITH
STRONG SOUTHEASTERLY WINDS AHEAD OF THE FRONT AND A FEW
THUNDERSTORMS...MAINLY ACROSS SOUTHERN LAKE MICHIGAN. EXPECT GALE
FORCE WINDS TO OVERSPREAD THE LAKE BY EARLY THIS MORNING. WINDS MAY
SLACKEN SOMEWHAT IN THE FRONTAL TROUGH AS THE WARM FRONT LIFTS
ACROSS THE LAKE...BUT STRONG SOUTHWESTERLY WINDS WILL FILL IN BEHIND
THE FRONT AS A STRONG LOW-LEVEL JET DEVELOPS JUST TO THE SOUTH OF
LAKE MICHIGAN. BY THE EARLY MORNING HOURS THURSDAY...THE LOW WILL
BEGIN TO WEAKEN AS IT MOVES EAST OF LAKE MICHIGAN WITH A WEAK RIDGE
OF HIGH PRESSURE TRANSITING ACROSS THE LAKE THURSDAY AFTERNOON
ALLOWING WINDS TO DIMINISH. ANOTHER LOW PRESSURE SYSTEM WILL
COALESCE OVER THE SOUTHERN PLAINS EARLY FRIDAY...THEN MOVE NORTHEAST
AND DEEPEN AS IT PUSHES ACROSS LAKE MICHIGAN FRIDAY EVENING. GALE
FORCE WINDS WILL BE POSSIBLE AGAIN BEHIND THIS LOW ON SATURDAY. BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WIND ADVISORY...ILZ019-ILZ020-ILZ021-ILZ022-ILZ023-ILZ032-ILZ033-
ILZ039...9 AM WEDNESDAY TO 6 PM WEDNESDAY.
IN...WIND ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019...9 AM
WEDNESDAY TO 6 PM WEDNESDAY.
LM...GALE WARNING...LMZ080-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ872-
LMZ874-LMZ876-LMZ878 UNTIL 9 PM WEDNESDAY.
GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
LMZ669-LMZ868-LMZ870 UNTIL 3 PM WEDNESDAY.
GALE WARNING...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745...8 AM
WEDNESDAY TO 9 PM WEDNESDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 8 AM WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
340 AM CST WED FEB 29 2012
.DISCUSSION...
340 AM CST
A RATHER COMPLEX PATTERN LEADS TO A COMPLICATED SHORT TERM PERIOD OF
THE FORECAST WITH SEVERAL CONCERNS INCLUDING THUNDER POTENTIAL NEXT
FEW HOURS...WIND GUSTS THROUGH THE AFTERNOON...TEMP TRENDS...AND
ADDITIONAL PRECIP CHANCES/TYPE INTO THE EVENING. EARLY MORNING WATER
VAPOR IMAGERY SHOWS THE CLOSED UPPER LOW RESPONSIBLE FOR ALL OF THE
ABOVE SPINNING OVER NORTHWEST IOWA AND HEADING EAST. BEHIND IT...LOW
AMPLITUDE RIDGING IS WORKING ACROSS THE CENTRAL AND NORTHERN ROCKIES
WITH ANOTHER CLOSED UPPER LOW COMING ONSHORE OVER THE PACIFIC
NORTHWEST. THIS LOW WILL BE SIGNIFICANT FOR THE LOCAL AREA FRIDAY.
AT THE SURFACE...LOW PRESSURE CONTINUES SPIN OVER FAR NORTHERN IOWA
AND FAR SOUTHERN MINNESOTA AND IS BEGINNING TO OCCLUDE...WITH A WARM
FRONT EXTENDING SOUTHEASTWARD AND JUST NOW MOVING NORTHWARD INTO THE
EXTREME SOUTHERN CWA...AND A COOL FRONT CROSSING THE MISSISSIPPI
RIVER INTO WEST CENTRAL AND SOUTHWEST ILLINOIS WITH A STRONGER COLD
FRONT TRAILING IT TO THE WEST. BROAD AREA OF WARM ADVECTION SHOWERS
AND THUNDERSTORMS IS EXITING TO THE NORTHEAST WHILE ANOTHER ROUND OF
SHOWERS AND EMBEDDED THUNDERSTORMS LIFTS NORTHEASTWARD AHEAD OF THE
WARM FRONT/OCCLUSION WITH AN EXTENSION SOUTHWARD DOWN THE INITIAL
COOL FRONT.
TODAY AND TONIGHT...THE WARM FRONT WILL CONTINUE TO LIFT
NORTHEASTWARD ACROSS THE AREA OVER THE NEXT FEW HOURS WHILE THE
INITIAL COOL FRONT...WHICH IS REALLY MORE OF MARKER FOR THE LEADING
EDGE OF A DRIER AIRMASS...SPREADS EASTWARD. THE WARM/MOIST SECTOR
BETWEEN THE TWO IS RATHER COMPACT AND IS JUST NOW MOVING INTO THE
FAR SOUTHERN CWA AT 09Z. IN TERMS OF THUNDERSTORMS...LATEST RADAR
TRENDS AND SHORT TERM GUIDANCE BRING THE NEXT BAND OF
SHOWERS/EMBEDDED THUNDER ACROSS THE AREA BETWEEN NOW AND ABOUT 12Z
AS THE WARM FRONT LIFTS NORTHWARD. LAST FEW RADAR SCANS SHOW SOME
NEW DEVELOPMENT ON THE SOUTHERN END OF THE ORIGINAL LINE FROM
GALESBURG TO MACOMB TO QUINCY WHICH APPEARS TO BE RIGHT ALONG THE
DRY BOUNDARY. ANOTHER LINE OF CONVECTION IS ONGOING FROM BLOOMINGTON
SOUTHWARD AND WAS INITIALLY TIED TO THE FRONT BUT NOW APPEARS TO BE
OUT AHEAD OF IT. THIS NEW DEVELOPMENT IS OF SOME CONCERN IN THAT IT
WILL LIKELY CROSS THE SOUTHERN CWA WHICH WILL LIKELY BE IN THE WARM
SECTOR IN THE NEXT FEW HOURS. LATEST SPC MESOANALYSIS SHOWS SURFACE
BASED INSTABILITY NOSING UP THROUGH THE ST. LOUIS AREA WITH LATEST
SHORT TERM GUIDANCE KEEPING SURFACE BASED INSTABILITY TO THE SOUTH.
RECENT RUC SOUNDING FOR PONTIAC ALSO SHOWS AT LEAST A MINIMAL
INVERSION REMAINING IN PLACE DESPITE THE WARM SECTOR MOVING IN. SO
SEVERE WIND THREAT IS PRETTY MINIMAL BUT WITH LOW LEVEL WINDS OF 50
KT BY 2000 FT OR SO STILL HAVE CONCERNS FOR SOME GUSTS MAKING IT TO
THE SURFACE IF CONVECTION CAN MAINTAIN ITSELF.
SHOWERS/THUNDERSTORMS SHOULD QUICKLY WRAP UP AS THE DRY BOUNDARY
CROSSES THE AREA IN THE 12-15Z TIME FRAME...BRINGING IN LOWER
DEWPOINT AIR. WINDS WILL TURN SOUTHWESTERLY AS THE FRONT PASSES WITH
SPEEDS INCREASING AS THE PRESSURE GRADIENT INCREASES AND MIXING WILL
FURTHER BE AIDED BY THE PRESENCE OF THE DRY PUSH OF AIR. THE
WINDIEST PERIOD WILL LIKELY BE THIS AFTERNOON AS A LOW LEVEL SPEED
MAX MOVES ACROSS THE AREA ON THE SOUTHERN FLANK OF THE TROUGH WHICH
ALSO COINCIDES WITH LOWEST TROPOPAUSE HEIGHTS AND THE ARRIVAL OF
COLD ADVECTION. WITH THE CORE OF STRONGEST H92 WINDS IN THE 40-45 KT
RANGE SPREADING INTO THE SOUTHERN CWA WILL GO AHEAD WITH A WIND
ADVISORY GENERALLY ALONG AND SOUTH OF INTERSTATE 80 FROM MID MORNING
INTO EARLY EVENING. THIS WILL SUPPORT GUSTS TO 50 MPH AT TIMES. DO
HAVE A CONCERN FOR HIGH WIND WARNING CRITERIA TO BE MET AS WELL IN
THE FAR SOUTH IF MIXING CAN DEEPEN ENOUGH. MIXING TO H85 WHERE WINDS
WILL BE 50 KT OR A LITTLE BETTER IS A POSSIBILITY GIVEN THE ABOVE
FACTORS SO THIS WILL NEED TO BE MONITORED IN THE SHORT TERM.
TEMPS...WITH THE WARM FRONT LIFTING INTO THE AREA THIS MORNING TEMPS
WILL INCREASE FROM SOUTH TO NORTH AND LIKELY PEAK DURING THE MID TO
LATE MORNING BEFORE COLD ADVECTION ARRIVES. FAIRLY DECENT BUST
POTENTIAL EXISTS WITH THE COMPLEX SURFACE PATTERN IN PLACE. HAVE
SLOWED THE WARMING BASED ON LATEST TRENDS WHICH ALSO SEEM TO SUPPORT
THE NORTHWARD EXPANSE OF THE WARMEST AIR BEING LIMITED. WILL HOLD
HIGHS IN THE NORTHWEST TO THE MID TO UPPER 40S WITH MID TO UPPER 50S
SOUTH OF A CHICAGO TO LASALLE LINE AND LOW TO MID 60S SOUTH OF A
VALPARAISO TO PONTIAC LINE. THE HIGHS WILL BE A BALANCE OF HOW
QUICKLY THE WARM SECTOR ARRIVES AND HOW FAR NORTH AND WEST IT CAN
EXPAND...AND DEPTH OF MIXING THIS MORNING BEFORE COOLER MID LEVEL
AIR ARRIVES EARLY THIS AFTERNOON. HAVE GOOD CONFIDENCE IN THE TRENDS
BUT A FAIR AMOUNT LESS IN THE SPECIFIC VALUES. TEMPS WILL BEGIN TO
FALL IN THE WEST BUT WILL PROBABLY BE A GRADUAL COOLING GIVEN THAT
THE LOW/MID LEVEL TEMP GRADIENT IS NOT IMPRESSIVELY SHARP...AT LEAST
THROUGH MID AFTERNOON. WILL CARRY A COOLING TREND BUT THE SPEED OF
THE COOLING MAY NEED SOME ADJUSTING.
THE CENTER OF THE UPPER LOW WILL PASS NORTH OF THE AREA LATE THIS
AFTERNOON AND EARLY THIS AFTERNOON. THIS WILL BRING A PUSH OF
FORCING BACK TO THE AREA IN ADDITION TO A RETURN OF DEEPER MOISTURE.
IT WILL ALSO PROVIDE A STRONGER PUSH OF COLD AIR. THIS MAY ACT IN
CONJUNCTION WITH NORMAL DIURNAL COOLING TO PROVIDE A FASTER TEMP
DROP LATE THIS AFTERNOON INTO EARLY THIS EVENING. PRECIP CHANCES
WILL RETURN TO MAINLY THE NORTHERN HALF OF THE AREA FROM I-80 NORTH
DURING THE MID/LATE AFTERNOON. MIXED PRECIP IS EXPECTED...WITH
NORTHWEST AREAS PROBABLY SEEING A RAIN SNOW MIX..POSSIBLY WITH SOME
SLEET AS WELL...CHANGING OVER TO SNOW. GOING FURTHER SOUTH AND EAST
RAIN WILL PROBABLY OCCUR AT THE START THEN TRANSITION TO A RAIN/SNOW
MIX BEFORE CHANGING TO ALL SNOW WITH WHATEVER PRECIP IS LEFT DURING
THE EVENING. THE GREATEST PRECIP COVERAGE WILL BE NORTH OF I-88 WITH
LESS EXPECTED TO THE SOUTH AND PROBABLY LITTLE IF ANY SOUTH OF I-80.
HOWEVER...RECENT MODEL TRENDS HAVE BEEN FURTHER SOUTH WITH THE
RETURN OF THE MOISTURE SO A SOUTHWARD EXPANSION OF POPS MAY BE
NEEDED FOR THE LATE AFTERNOON. THE BULK OF THE ENERGY WILL BE OFF TO
THE EAST BY MID/LATE EVENING BUT CYCLONIC FLOW WILL PROBABLY KEEP
FLURRIES GOING INTO THE OVERNIGHT. BREEZY WEST WINDS WILL CONTINUE
THROUGH THE NIGHT BUT BE MUCH LOWER IN SPEED THAN DURING THE
AFTERNOON. OVERNIGHT LOWS WILL RANGE FROM THE UPPER 20S NORTH TO
LOWER 30S SOUTH.
THURSDAY THROUGH SATURDAY...A BIT OF A BREAK WILL ARRIVE THURSDAY AS
HIGH PRESSURE AND THE UPPER RIDGING CURRENTLY OVER THE ROCKIES
DRIFTS ACROSS THE AREA. THE HIGH IS NOT THAT STRONG AND FOCUSED TO
THE SOUTH SO A WEST BREEZE WILL CONTINUE WHICH WILL HELP MIXING. MID
LEVEL WARM ADVECTION WILL BE UNDERWAY BY AFTERNOON WITH H85 TEMPS
EXPECTED TO BE IN THE 0 TO +4 C RANGE BY EVENING. IT DOESN/T LOOK
LIKE THE MOST IDEAL SET UP FOR MAXIMUM WARMING...ESPECIALLY SINCE
THE THE WARMEST AIR ALOFT ARRIVES LATER IN THE DAY. EXPECT THAT
HIGHS SHOULD WARM INTO THE LOW TO MID 40S NORTH TO NEAR 50 SOUTH. IT
IS POSSIBLE THAT A LATE DAY RALLY MAY ALLOW TEMPS TO WARM AN
ADDITIONAL COUPLE DEGREES. THE UPPER TROUGH CURRENTLY MOVING OVER
THE WEST COAST WILL BE SPREADING ACROSS THE ROCKIES AND INTO THE
HIGH PLAINS WHICH WILL TRIGGER SURFACE LOW DEVELOPMENT ACROSS
OKLAHOMA FRIDAY MORNING. A SHORTWAVE IS EXPECTED TO ZIP NORTHWARD UP
THE EASTERN PERIPHERY OF THE LONGER WAVE TROUGH LATE THURSDAY NIGHT
AND ENHANCE WARM ADVECTION WHICH MAY BE SUFFICIENT TO BRING SOME
LIGHT PRECIP ACROSS THE NORTHWEST CWA INTO EARLY FRIDAY.
THEN...ANOTHER SHORTWAVE IS EXPECTED TO WORK NORTHEASTWARD BEHIND IT
AND PUSH THE DEVELOPING SURFACE LOW NORTHEASTWARD INTO FRIDAY
EVENING. GFS/ECMWF/UKMET/GEM IN DECENT AGREEMENT ON TAKING THE LOW
ACROSS NORTH CENTRAL INDIANA WHILE THE NAM IS A BIT FURTHER WEST
TAKING THE LOW ACROSS THE IL/IN BORDER NEAR GARY. THE BULK OF THE
PRECIP LOOKS TO OCCUR DURING THE AFTERNOON AND EARLY EVENING FRIDAY.
MOST OF IT WILL FALL AS RAIN BUT COLDER AIR WORKING EASTWARD WITH
THE UPPER TROUGH WILL MOVE INTO THE FAR NORTHWEST DURING THE LATE
AFTERNOON LIKELY RESULTING IN A RAIN/SNOW MIX. FAR EASTERN AREAS MAY
SEE SOME EMBEDDED THUNDERSTORMS AS WELL. THE LOW QUICKLY EXITS TO
THE NORTHEAST FRIDAY EVENING WITH COLD ADVECTION ACROSS THE AREA.
ANOTHER TROUGH AXIS MOVES THROUGH THE LONGWAVE AND ACROSS THE AREA
SATURDAY MORNING BUT PRECIP CHANCES LOOK PRETTY MINOR AT THE MOMENT.
TEMPS FRIDAY WILL RANGE FROM THE MID/UPPER 40S NORTHWEST...THOUGH
COOLING LATE...TO THE MID OR UPPER 50S SOUTHEAST WHILE HIGHS
SATURDAY WILL RANGE FROM THE UPPER 30S TO LOWER 40S.
SUNDAY THROUGH TUESDAY...THERE IS GENERAL AGREEMENT IN A LONGWAVE
TROUGH EAST AND A BIG RIDGE WEST FROM LATE IN THE WEEKEND INTO EARLY
NEXT WEEK. SUNDAY MAY SEE PRECIP CHANCES WITH INDICATIONS OF A WAVE
TRAVERSING THE MAIN TROUGH. THINGS BEGIN TO SHIFT MONDAY AND TUESDAY
WITH RIDGING APPROACHING OR REACHING THE LOCAL AREA RESULTING IN A
WARM UP...BUT IT IS NOT CLEAR HOW QUICKLY THIS WILL ARRIVE.
MDB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 08Z...
* ARRIVAL LOCALLY OF RA AND TS MOVING ENE FM E CENTRAL IA AND W
CENTRAL IL.
* IFR CONDITIONS PERSISTING INTO MID AFTERNOON.
* LLWS TIL MID MORNING.
* STRONG SE WINDS BECOMING SW AND GUSTY BY MID MORNING...INCREASING
TO STRONG WITH G35-45KT LIKELY LATE MORNING WELL INTO AFTERNOON.
TRS
//DISCUSSION...UPDATED 06Z...
A VERY SLOPPY WX PICTURE EVOLVING WITH MULTIPLE WX CONCERNS. A LOW
PRESSURE SYSTEM IS DEEPENING OVER THE UPPER MISSOURI VALLEY WILL
TURN EAST TRACK THROUGH SRN MN/WI TOMORROW. THIS SYSTEM IS DRAWING
MOISTURE NWD FROM THE GLFMEX...AND OVERRUNNING AN ASSOCIATED WARM
FRONT EXTENDING THROUGH SRN IOWA TO SRN IL/IN. WIDESPREAD RAIN HAS
OVERSPREAD THE AREA...WITH THE LATEST RADAR IMAGERY SHOWING MORE
CONVECTIVE ELEMENTS AND SCT TS ALONG AND SOUTH OF THE WARM FRONT.
AT ISSUANCE TIME...CONDITIONS WILL BE APPROACHING MVFR LEVELS AND
EXPECT CIGS/VIS TO DROP TO MVFR BY AROUND MIDNIGHT. THERE WILL BE
ENOUGH ELEVATED INSTABILITY TO SUPPORT ISOLD/EMBEDDED TS...BUT
COVERAGE SHOULD BE SPARSE AND HAVE LITTLE CONFIDENCE ON ANY TIMING
OR DURATION OF TS AT THE TERMINALS. SO...WILL CONTINUE TO LIMIT
THE TS MENTION IN THE TAFS TO JUST VCTS AND CB GROUPS. CONFIDENCE
IS HIGHER ON THE OTHER IMPACTS ON SERVICE IN THE POTENTIAL FOR IFR
CONDITIONS AS THE WARM FRONT LIFTS NWRD THROUGH NRN IL EARLY
TOMORROW MORNING. THERE IS ALSO SOME CONCERN IN THE POSSIBILITY OF
STRONGER...MORE LINEAR TS DEVELOPING WITH THE COLD FRONT PASSAGE.
THE SHORT RANGE MODEL GUIDANCE INDICATES THAT THE COLD FRONT
SHOULD QUICKLY PUSH THROUGH THE AREA TOMORROW MORNING BTWN 12-16Z.
THERE ARE INDICATIONS OF THE POTENTIAL FOR INCREASED SURFACE BASED
INSTABILITY AND A WARM SECTOR ENVIRONMENT PUSHING QUICKLY THROUGH
THE AREA BETWEEN THE TIME THAT THE WARM FRONT LIFTS TO THE NORTH
AND THE COLD FRONT SWEEPS EWD ACROSS IL/IN. THIS WOULD PROVIDE A
BRIEF WINDOW OF OPPORTUNITY FOR STRONGER TS TO DEVELOP...BUT
CONFIDENCE IN TIMING IS LOW. FOLLOWING THE PASSAGE OF THE SFC COLD
FRONT...DRY AIR ALOFT WILL OVERRIDE A MOIST LAYER BLW 5KFT...SO A
PERIOD OF DZ WITH IFR CIGS/VIS IS LIKELY THOUGH ARND 18Z. ALSO
FOLLOWING THE FROPA...WINDS WILL VEER SWLY AND QUICKLY STRENGTHEN
THROUGH THE MORNING...WITH GUSTS OF 35KT...OR POSSIBLY
HIGHER...ARE EXPECTED THROUGH THE REMAINDER OF THE AFTERNOON.
BY LATE TOMORROW EVENING...WRAPAROUND MOISTURE AND CYCLONIC FLOW
ALOFT ALONG WILL COOLER AIR FILTERING INTO THE AREA BEHIND THE
EXITING LOW WILL BRING BACK MVFR CIGS AND SOME LIGHT SNOW. WITH
THE COLD CORE UPPER LOW MOVING OVER SRN WI DURG THE
EVENING...THERE MAY BE ENOUGH INSTABILITY FOR SOME HEAVIER SNOW
SHOWERS OR GRAUPEL WITH THE LIGHT SNOW.
KREIN
//ORD AND MDW CONFIDENCE...UPDATED 08Z...
* HIGH CONFIDENCE IN LLWS EARLY THIS MORNING.
* HIGH CONFIDENCE IN WIND TRENDS...WITH MEDIUM CONFIDENCE IN GUST
SPEEDS LATER TODAY.
* MEDIUM CONFIDENCE IN CIG/VIS TRENDS.
* MEDIUM CONFIDENCE IN PRECIP BEGINNING AND ENDING TIMES.
* MEDIUM CONFIDENCE TS WILL BE ISOLD OR FEW PREDAWN TO DAWN
ACROSS ORD AND MDW AREA.
TRS
//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...
THURSDAY...VFR. WX NIL.
FRIDAY...MVFR CIGS/VIS. RAIN OR A RAIN/SNOW MIX LIKELY DURING THE
DAY...CHANCE OF LIGHT SNOW AT NIGHT.
SATURDAY...VFR...SLIGHT CHANCE OF LIGHT SNOW OR FLURRIES EARLY...STRONG
GUSTY GUSTY W WINDS IN THE AFTERNOON.
SUNDAY...VFR. SLIGHT CHANCE LIGHT SNOW EARLY.
MONDAY...VFR. WX NIL.
KREIN
&&
.MARINE...
303 AM CST
A STRONG AREA OF LOW PRESSURE OVER THE MID-MISSOURI VALLEY EARLY
THIS MORNING WILL TRACK NORTHEAST ACROSS LAKE MICHIGAN TONIGHT.
AHEAD OF THE LOW...A WARM FRONT WILL LIFT NORTH ACROSS THE LAKE WITH
STRONG SOUTHEASTERLY WINDS AHEAD OF THE FRONT AND A FEW
THUNDERSTORMS...MAINLY ACROSS SOUTHERN LAKE MICHIGAN. EXPECT GALE
FORCE WINDS TO OVERSPREAD THE LAKE BY EARLY THIS MORNING. WINDS MAY
SLACKEN SOMEWHAT IN THE FRONTAL TROUGH AS THE WARM FRONT LIFTS
ACROSS THE LAKE...BUT STRONG SOUTHWESTERLY WINDS WILL FILL IN BEHIND
THE FRONT AS A STRONG LOW-LEVEL JET DEVELOPS JUST TO THE SOUTH OF
LAKE MICHIGAN. BY THE EARLY MORNING HOURS THURSDAY...THE LOW WILL
BEGIN TO WEAKEN AS IT MOVES EAST OF LAKE MICHIGAN WITH A WEAK RIDGE
OF HIGH PRESSURE TRANSITING ACROSS THE LAKE THURSDAY AFTERNOON
ALLOWING WINDS TO DIMINISH. ANOTHER LOW PRESSURE SYSTEM WILL
COALESCE OVER THE SOUTHERN PLAINS EARLY FRIDAY...THEN MOVE NORTHEAST
AND DEEPEN AS IT PUSHES ACROSS LAKE MICHIGAN FRIDAY EVENING. GALE
FORCE WINDS WILL BE POSSIBLE AGAIN BEHIND THIS LOW ON SATURDAY. BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 8 AM WEDNESDAY.
GALE WARNING...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745...8 AM
WEDNESDAY TO 9 PM WEDNESDAY.
GALE WARNING...LMZ080-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ872-
LMZ874-LMZ876-LMZ878 UNTIL 9 PM WEDNESDAY.
GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
LMZ669-LMZ868-LMZ870 UNTIL 3 PM WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1159 PM CST TUE FEB 28 2012
.DISCUSSION...
ISSUED 856 PM CST TUE FEB 28 2012
SHOWERS AND THUNDERSTORMS HAVE MOVED INTO/EXPANDED ACROSS THE
FORECAST AREA AS A WARM FRONTAL ZONE HAS BEEN PUSHING IN FROM THE
SOUTHWEST. EXPECT THIS TREND TO PERSIST FOR AT LEAST THE NEXT FEW
HOURS. THEN...CHANCES WILL INCREASE AGAIN LATER TONIGHT AS A COLD
FRONT PUSHES IN BEHIND THE WARM FRONT. VIGOROUS THUNDERSTORM
DEVELOPMENT IS OCCURRING ACROSS THE COLD FRONT AT THE
MOMENT...THOUGH THERE IS STILL CONSIDERABLE DOUBT ABOUT THE RISK
OF THESE STRONG STORMS MAKING IT THIS FAR EAST. STILL EXPECT A
DOWNWARD TREND IN THE STORMS BEFORE THEY REACH HERE DUE TO THE
LESS FAVORABLE TIME OF DAY. ALSO...BY THE TIME ANY LINGERING
STORMS GET HERE...THEY SHOULD BE INCREASINGLY ELEVATED.
STILL...WILL NEED TO KEEP AN EYE ON THE SEVERE WIND THREAT WITH
MODELS STILL SUGGESTING A 60-70 KT LOW LEVEL JET AT 850 MB JUST
AHEAD OF THE FRONT.
GOING FORECAST IS IN GOOD SHAPE OVERALL. ONLY MINOR TWEAKS ARE
ANTICIPATED FOR THE LATEST TRENDS.
BAK
&&
.AVIATION...
ISSUED 1159 PM CST TUE FEB 28 2012
INITIAL WAVE OF SHOWERS/STORMS FOR THE CENTRAL ILLINOIS TERMINALS
HAS ENDED FOR THE MOST PART...LEAVING MAINLY MVFR CONDITIONS.
ANOTHER COUPLE HOUR PERIOD OF SHOWERS/STORMS POSSIBLE LATE TONIGHT
ALONG THE COLD FRONT...WHICH COULD PRODUCE IFR CONDITIONS.
THEN...VFR CONDITIONS AND GUSTY SOUTHWEST WINDS EXPECTED BEHIND THE
FRONT FOR WEDNESDAY. WIND GUSTS WILL EXCEED 40 KTS AT TIMES FOR
THE DAYTIME HOURS.
BAK
&&
.PREV DISCUSSION...
ISSUED 257 PM CST TUE FEB 28 2012
MAIN CHALLENGES WITH THIS FORECAST PACKAGE ARE WITHIN THE
SHORT-TERM...AS TWO SEPARATE STORM SYSTEMS ARE EXPECTED TO IMPACT
CENTRAL ILLINOIS OVER THE NEXT COUPLE OF DAYS.
SHORT TERM...TONIGHT THROUGH FRIDAY
LOW PRESSURE DEVELOPING IN THE LEE OF THE ROCKIES WILL LIFT
NORTHEASTWARD INTO THE UPPER MIDWEST TONIGHT...SPREADING SHOWERS
AND THUNDERSTORMS ACROSS CENTRAL ILLINOIS. AIRMASS IS INITIALLY
QUITE DRY...AS EVIDENCED BY 20Z SURFACE DEWPOINTS IN THE MIDDLE
TO UPPER 20S...THEREFORE ONSET OF PRECIP WILL LIKELY HOLD OFF
UNTIL MID TO LATE EVENING...WHEN WINDS BEGIN TO VEER TO A MORE
SOUTHERLY DIRECTION AND LOW-LEVELS MOISTEN. ONCE DEEPER MOISTURE
ARRIVES...SHOWERS AND A FEW THUNDERSTORMS WILL DEVELOP ACROSS THE
AREA IN ADVANCE OF A WARM FRONT. ALL MODELS PUSH THIS PRECIP
EASTWARD INTO INDIANA OVERNIGHT...AS THE ENTIRE KILX CWA PUNCHES
INTO THE WARM SECTOR OF THE STORM SYSTEM.
NEXT QUESTION WILL BE HOW MUCH CONVECTION WILL DEVELOP ALONG THE
APPROACHING COLD FRONT LATE TONIGHT INTO EARLY WEDNESDAY MORNING.
HIGH-RES MODELS SUCH AS THE HRRR AND 4KM WRF-NMM SUGGEST A BROKEN
LINE OF STORMS FORMING ALONG THE FRONT AND PUSHING INTO ILLINOIS
AFTER 09Z. FORECAST SOUNDINGS REVEAL A HIGH DEGREE OF LOW-LEVEL
WIND-SHEAR NEAR THE WARM FRONT...HOWEVER ELEVATED INSTABILITY
APPEARS TO BE RATHER MINIMAL. DESPITE MODEST INSTABILITY...VIGOROUS
UPPER DYNAMICS AND STRENGTHENING 850MB JET WILL BE MORE THAN ENOUGH
TO TRIGGER THUNDERSTORMS ALONG THE COLD FRONT TOWARD DAWN WEDNESDAY.
SEVERE THREAT WILL BE LIMITED DUE TO STABLE SURFACE-BASED
LAYER...HOWEVER THINK A FEW STORMS WILL BE STRONG ENOUGH TO MIX
HIGHER MOMENTUM AIR DOWN TO THE SURFACE PRODUCING MARGINALLY
SEVERE WIND GUSTS. PRIMARY TIME FRAME FOR SEVERE POTENTIAL WILL BE
BETWEEN 3 AM AND 9 AM.
COLD FRONT WILL PUSH EASTWARD INTO INDIANA BY AROUND MIDDAY...ENDING
ANY THREAT FOR MORNING SHOWERS/STORMS. DUE TO STRONG SOUTHERLY
FLOW AHEAD OF THE BOUNDARY...HIGH TEMPS WILL SURGE WELL INTO THE
60S ACROSS MUCH OF THE AREA...AND MAY EVEN REACH THE 70 DEGREE MARK
ACROSS THE FAR SOUTHEAST CWA. ONCE THE FRONT PASSES...READINGS WILL
LIKELY FALL A FEW DEGREES DURING THE AFTERNOON. BIG STORY ON
WEDNESDAY WILL BE THE VERY STRONG WINDS...AS PRESSURE GRADIENT
TIGHTENS BETWEEN EXITING FRONT AND APPROACHING HIGH PRESSURE.
SUSTAINED WINDS WILL INCREASE INTO THE 20 TO 30 MPH RANGE...WITH
GUSTS POTENTIALLY EXCEEDING 40 MPH.
QUIET WEATHER WILL BE ON TAP FOR THURSDAY...AS HIGH PRESSURE
DRIFTING OVERHEAD BRINGS CLEAR SKIES AND LIGHT WINDS. THE BREAK IN
THE ACTION WILL BE SHORT-LIVED HOWEVER...AS NEXT UPPER TROUGH
QUICKLY DIGS ACROSS THE WESTERN CONUS AND SURFACE LOW PRESSURE
ONCE AGAIN FORMS IN THE LEE OF THE ROCKIES. MODELS HAVE BEEN
STRUGGLING WITH THE TRACK OF THIS SYSTEM FOR THE PAST FEW
DAYS...AND THE 12Z 28 FEB SUITE IS NO EXCEPTION. THE NAM CONTINUES
TO BE THE FURTHEST EAST WITH THE LOW TRACK...TAKING IT FROM
NORTHERN ARKANSAS AT 12Z FRI TO CENTRAL INDIANA BY 18Z FRI.
ON THE OTHER HAND...THE GFS IS FURTHEST WEST...POSITIONING THE LOW
NEAR QUINCY ILLINOIS BY 18Z FRI. MEANWHILE...THE ECMWF REPRESENTS
A COMPROMISE BETWEEN THE TWO TRACKS AND HAS BEEN THE MOST
CONSISTENT SOLUTION OVER THE PAST FEW RUNS. AS A RESULT...HAVE
TRENDED TOWARD THE ECMWF WITH THE LATE WEEK STORM SYSTEM.
WITH LOW PRESSURE TRACKING ACROSS CENTRAL/EAST-CENTRAL ILLINOIS
DURING THE DAY FRIDAY...SHOWERS AND A FEW THUNDERSTORMS WILL BE
LIKELY. GIVEN EXPECTED TRACK...HAVE FOCUSED THUNDER ACROSS THE
EASTERN TWO-THIRDS OF THE CWA...WHILE KEEPING THE ILLINOIS RIVER
VALLEY ON THE COOL SIDE OF THE SYSTEM AND CONVECTION FREE. AS THE
LOW LIFTS INTO THE GREAT LAKES...W/NW WINDS WILL BRING COLDER AIR
INTO THE REGION BY FRIDAY NIGHT. LINGERING RAIN SHOWERS DURING THE
EVENING MAY CHANGE TO SNOW-SHOWERS OVERNIGHT...HOWEVER NO
ACCUMULATION IS ANTICIPATED.
LONG TERM...SATURDAY THROUGH TUESDAY
COOL/TRANQUIL WEATHER IS IN STORE FOR THE WEEKEND...AS UPPER TROUGH
DIGS OVER THE EASTERN CONUS. WEAK SHORT-WAVE WILL SLIDE
SOUTHEASTWARD INTO THE REGION ON SUNDAY...HOWEVER MOISTURE WILL BE
EXTREMELY LIMITED...SO DO NOT ANTICIPATE ANY PRECIP. THE TROUGH
WILL GRADUALLY SHIFT FURTHER EASTWARD EARLY NEXT WEEK...ALLOWING A
WARMING TREND TO GET UNDERWAY BY MONDAY AND TUESDAY. THE NEXT
SIGNIFICANT STORM SYSTEM WILL LIKELY HOLD OFF UNTIL THE MIDDLE OR
END OF NEXT WEEK...SO DRY WEATHER IS EXPECTED THROUGH THE ENTIRE
EXTENDED.
BARNES
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM 9 AM TO 6 PM CST WEDNESDAY FOR ILZ027>031-
036>038-040>057-061.
&&
$$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
354 PM EST WED FEB 29 2012
.UPDATE...
THE SYNOPSIS...NEAR TERM...SHORT TERM AND LONG TERM SECTIONS HAVE
BEEN UPDATED BELOW.
&&
.SYNOPSIS...
SURFACE AND UPPER LEVEL LOW WILL PUSH THROUGH THE GREAT LAKES
OVERNIGHT...WITH SOME ADDITIONAL CLOUDINESS POSSIBLE OVERNIGHT.
GUSTY WINDS ASSOCIATED WITH THE SYSTEM WILL SUBSIDE OVERNIGHT.
HIGH PRESSURE WILL RETURN QUIET WEATHER TO THE AREA THROUGH
FRIDAY...WHEN ANOTHER LOW PRESSURE SYSTEM PUSHES INTO THE AREA
FRIDAY AND FRIDAY NIGHT...BRINGING THE POTENTIAL FOR THUNDERSTORMS
AND PERHAPS SEVERE WEATHER TO THE AREA.
THE REMAINDER OF THE FORECAST PERIOD WILL GENERALLY BE
QUIET...WITH HIGH PRESSURE IN PLACE.
&&
.NEAR TERM /THIS AFTERNOON AND TONIGHT/...
FOCUS IS ON WINDS THIS AFTERNOON AND SKY COVER/TEMPS OVERNIGHT.
GUIDANCE IS SIMILAR AND A BLEND IS USED.
HAVE TRIMMED WIND ADVISORY BACK TO JUST THE NORTHWEST CORNER OF
THE FORECAST AREA...AS STRONGER GUSTS HAVE NOT MATERIALIZED ACROSS
MUCH OF THE AREA. HOWEVER...STRONGER GUSTS ARE OCCURRING IN THE
NORTHWEST...AND 40 PLUS KNOT GUSTS ARE OCCURRING JUST TO OUR
NORTHWEST. RUC SOUNDINGS INDICATE THE POTENTIAL FOR THESE TO MAKE
THE NORTHWEST FORECAST AREA LATE THIS AFTERNOON BEFORE GUSTS
SUBSIDE THIS EVENING.
CLOUD COVER ASSOCIATED WITH UPPER LOW WILL BRUSH OUR NORTHERN
THIRD OR SO OF THE FORECAST AREA OVERNIGHT...BUT SOUTHERN PORTIONS
WILL REMAIN CLEAR.
SOME WEAK ISENTROPIC LIFT WILL SKIRT THE NORTHERN PORTIONS OF THE
FORECAST AREA THIS EVENING...AND MAY SEE A COUPLE OF SPRINKLES OR
A BIT OF DRIZZLE...BUT THIS IS RATHER UNCERTAIN SO CHOSE TO
EXCLUDE A MENTION AT THIS TIME.
ON TEMPS...FEEL THAT MOS IS A BIT TOO COOL...ESPECIALLY GIVEN THAT
CONDITIONS WILL GENERALLY REMAIN SOMEWHAT BREEZY OVERNIGHT AND
CLOUD COVER WILL ALSO CONTRIBUTE TO KEEPING THINGS A BIT WARMER
IN SPOTS. HAVE RAISED CONSENSUS A COUPLE OF DEGREES...AND THIS IS
WELL IN LINE WITH UPSTREAM MINS FROM LAST NIGHT.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY/...
FOCUS IS ON POTENTIAL FOR THUNDERSTORMS FRIDAY AND FRIDAY
NIGHT...AS WELL AS POSSIBLE SEVERE WEATHER. SIGNIFICANT GUIDANCE
DISCREPANCIES NOTED IN THE STRENGTH AND POSITION OF SYSTEM PUSHING
INTO THE AREA DURING THIS TIME...AND HAVE TEMPERED EXPECTATIONS
TOWARD THE CONSENSUS WHILE NOT COMPLETELY DISCOUNTING THE
SIGNIFICANTLY STRONGER NAM.
HIGH PRESSURE WILL KEEP CONDITIONS DRY THROUGH TOMORROW NIGHT.
ANOTHER LOW PRESSURE SYSTEM APPROACHES FOR FRIDAY AND FRIDAY
NIGHT...AND THIS IS WHERE GUIDANCE DIVERGES. MUCH OF THE AVAILABLE
GUIDANCE LEANS TOWARD A BIT WEAKER AND FURTHER SOUTH
SOLUTION...SIMILAR TO LAST NIGHT AND TODAY...WITH THE COLD FRONT
THROUGH MUCH EARLIER IN THE DAY. NAM IS SIGNIFICANTLY STRONGER AND
MORE WOUND UP WITH THE LOW...AND IF THIS VERIFIES...A SIGNIFICANT
SEVERE WEATHER THREAT WILL BE POSSIBLE ACROSS MUCH OF THE
AREA...WITH ANY AND ALL THREATS POSSIBLE...AS SREF POSTPROCESSED
GUIDANCE INDICATES SIGNIFICANT LOW AND DEEP LAYER SHEAR AND WEAK
TO MODERATE INSTABILITY. OVERALL SHOWERS AND THUNDERSTORMS LOOK TO
BE A GOOD BET FRIDAY AFTERNOON AND EVENING...AND THE SEVERE THREAT
BEARS CLOSE SCRUTINY AS THE DAY APPROACHES.
ON TEMPS...GUIDANCE APPEARS TOO COOL THROUGHOUT...AND HAVE
ADJUSTED CONSENSUS UP MOST PERIODS. DEPENDING ON TIME OF WARM
FRONT ARRIVAL LATE THURSDAY NIGHT OR EARLY FRIDAY...A NON DIURNAL
TEMPERATURE PROGRESSION MAY BE NECESSARY THURSDAY NIGHT.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
PER THE EMSEMBLES THE EXTENDED PERIOD FOR THE MOST PART SHOULD BE
DRY...WITH A FEW EXCEPTIONS. A SHORTWAVE EMBEDDED IN THE UPPER TROF
PUSHING ACROSS THE SRN GREAT LAKES WILL BRING SOME PRECIP CHANCES TO
THE AREA ON SUNDAY...POSSIBLY MIXING WITH SOME LIGHT SNOW WELL NORTH
OF I-70 AS TEMPS APPEARS COOL ENOUGH. AFTER THAT A RIDGE BUILDS
INTHROUGH THE EARLY PORTION OF THE WEEK AND THEN A VERY STRONG FRONT
WILL APPROACH FROM THE WEST ON TUESDAY...BRINGING WHAT LOOKS LIKE A
GOOD CHANCE FOR SHOWERS TO THE REGION ON WED.
&&
.AVIATION /DISCUSSION FOR THE 29/2100Z TAF UPDATE/...
UPDATE...
NO CHANGES
PREVIOUS DISCUSSION...
APPEARS BROAD SURFACE FRONT WILL WORK IT/S WAY ACROSS THE REST OF
CENTRAL INDIANA THROUGH 19Z THIS AFTERNOON. NOT EXPECTING MUCH IN
THE WAY OF ACTIVITY WITH THIS FEATURE DUE TO WEAK LOW LEVEL
CONVERGENCE AND GENERAL DOWNWARD MOTION IN THE WAKE OF UPPER SYSTEM.
MODEL SOUNDINGS STILL CALLING FOR MFVR CEILINGS WITH THIS BUT THIS
SO FAR HAS NOT MATERIALIZED OVER THE AREA AND SO WILL GO WITH A
CLEAR TO MOSTLY CLEAR FORECAST.
SURFACE WIND GUSTS AROUND 35 KTS FROM W WILL CONTINUE THROUGH THIS
EVENING. MAY HAVE SOME MFVR CEILINGS DEVELOP EARLY THU MORNING FOR
KLAF AS AN UPPER LOW PUSHES EASTWARD ACROSS LWR MICHIGAN.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 7 PM EST THIS EVENING FOR INZ021-028>031-
035>038-043>045-051-052.
&&
$$
SYNOPSIS...NIELD
NEAR TERM...NIELD
SHORT TERM...NIELD
LONG TERM....SMF
AVIATION...SMF/TDUD
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
312 PM EST WED FEB 29 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
STRONG LOW PRESSURE OVER EASTERN NEBRASKA WILL PUSH TO
THE GREAT LAKES TONIGHT...DRAGGING A WARM FRONT ACROSS CENTRAL
INDIANA THIS MORNING AND A COLD FRONT ACROSS THE STATE TONIGHT.
THIS WILL BRING A ROUND OF SHOWERS AND THUNDERSTORMS TO CENTRAL
INDIANA THIS MORNING...ALONG WITH CHANCES THIS AFTERNOON.
FURTHERMORE A WINDY DAY IS EXPECTED AS A STRONG PRESSURE GRADIENT
IS EXPECTED.
DRY WEATHER WILL RETURN TONIGHT AND THURSDAY AS HIGH PRESSURE
MOVES THROUGH THE AREA. YET ANOTHER STORM SYSTEM WILL PUSH THROUGH
THE AREA ON FRIDAY AND THIS WILL BRING MORE CHANCES FOR SHOWERS
AND THUNDERSTORMS TO THE AREA.
A WEAKER SYSTEM WILL BRING CHANCES FOR PRECIPITATION ON
SUNDAY.
WELL ABOVE AVERAGE TEMPERATURES WILL CONTINUE FOR THE REMAINDER OF
THE WORK WEEK BEFORE NEAR AVERAGE READINGS RETURN FOR THE WEEKEND.
&&
.NEAR TERM /REST OF TODAY/...
MAIN ISSUE FOR THE MORNING UPDATE IS THE REMOVAL OF POPS FOR MOST
OF THE AREA FOR THE REST OF THE DAY AS THE DRY SLOT QUICKLY WORKS
INTO THE AREA. DID HOLD ONTO THE LOW CHANCES OF THUNDER IN THE FAR
SOUTHEAST THIS AFTERNOON AS THE RUC HINTS AT SOME DEVELOPMENT
BEGINNING THERE AND PROGRESSING EASTWARD LATER TODAY.
SKIES ARE OR WILL BECOME SUNNY ACROSS MOST OF THE FORECAST AREA
WITHIN THE NEXT FEW HOURS...AND SHOULD REMAIN SO FOR THE REMAINDER
OF THE AFTERNOON. CLOUDINESS UNDER THE CORE OF THE UPPER LOW MAY
IMPINGE UPON THE NORTHWEST FORECAST AREA BY LATE THIS
AFTERNOON/EARLY IN THE EVENING.
WIND ADVISORY STILL LOOKS GOOD FOR THE AFTERNOON...WITH FORECAST
SOUNDINGS CONTINUING TO INDICATE WINDS NEAR THE TOP OF THE MIXED
LAYER OF 40 PLUS KNOTS. GUSTS TO 40-45 MPH...PERHAPS EVEN
APPROACHING 50 MPH IN THE NORTHWEST...LOOK LIKELY THIS AFTERNOON.
MINOR TWEAKS ALSO REQUIRED TO TEMPS...BUT NOTHING SIGNIFICANT.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...
MODELS ARE IN PRETTY GOOD AGREEMENT DURING THIS PERIOD AND WILL
USE A BLEND.
TONIGHT THE STRONG LOW PRESSURE SYSTEM OVER THE GREAT LAKES
WILL PULL NORTHEAST AS STRONG SUBSIDENCE TAKES SHAPE AS RIDGING
BUILDS ACROSS INDIANA FROM THE CENTRAL PLAINS. FORECAST SOUNDINGS
REMAIN DRY AND ALTHOUGH A FEW STRATOCU COULD LINGER IN THE COLD
AIR ADVECTION AND BROAD CYCLONIC FLOW...SKIES SHOULD REMAIN JUST
PTCLDY TO CLEAR. GOOD MIXING DUE TO THE STILL PRESENT PRESSURE
GRADIENT IS EXPECTED TO CONTINUE OVERNIGHT...WHICH MAY OFFSET
RADIATIONAL COOLING EFFECTS. THUS WILL STICK CLOSE TO MAVMOS FOR LOWS.
MORE DRY WEATHER IS EXPECTED ON THURSDAY AND THURSDAY NIGHT AS
RIDGING BUILDS ACROSS THE REGION ALOFT. TIME HEIGHT SECTIONS AND
FORECAST SOUNDINGS REMAIN UNSATURATED...THUS MOSTLY CLEAR SKIES
ARE EXPECTED THURSDAY. STRONG WARM AIR ADVECTION ONCE AGAIN BEGINS TO TAKE
SHAPE ON THURSDAY NIGHT AS ANOTHER LOW PRESSURE SYSTEM BEGIN TO
SPIN UP OVER THE CENTRAL PLAINS. THIS SHOULD RESULT IN CREASING
MID AND HIGH CLOUDS. WILL TRENDS HIGHS ON THURSDAY AND LOWS ON
THURSDAY NIGHT WARMER THAN MAVMOS.
ANOTHER UPPER TROUGH IS EXPECTED TO PUSH OUT OF THE PLAINS STATES
ON FRIDAY AND FRIDAY NIGHT. WITH GOOD SUPPORT ALOFT AND VERY GOOD
WARM ADVECTION AHEAD OF A COLD FRONT...SHOWERS AND THUNDERSTORMS
ARE ONCE AGAIN EXPECTED TO BREAK OUT. FORECAST SOUNDINGS BY 00Z
SAT INDICATE CONVECTIVE TEMPERATURES THAT WILL EASILY BE REACHED
ALONG WITH A MOIST AIR MASS IN PLACE. THUS WILL TREND BEST CHANCES
DURING THE AFTERNOON AND EVENING HOURS AS THE COLD FRONT PASSES.
AS FOR TEMPS...PLENTY OF HEATING HOURS SHOULD BE AVAILABLE ON
FRIDAY AND WILL LEAN WARMER THAN MAVMOS. WITH THE COLD FRONTAL
PASSAGE AND STRONG COLD AIR ADVECTION ON FRIDAY NIGHT WILL TREND
FRIDAY NIGHT LOWS COLDER THAN MEXMOS.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
ENSEMBLE DATA INDICATE A DEEP UPPER TROUGH WILL BE MOVING EAST FROM
THE MIDWEST ON SATURDAY TO A POSITION OFF THE EAST COAST BY EARLY
NEXT WEEK. A FEW ENSEMBLES STILL INDICATE POTENTIAL FOR LIGHT QPF ON
SATURDAY UNDER THE UPPER TROUGH...BUT STILL NOT ENOUGH TO WARRANT A
POP ON SATURDAY. A WEAK SYSTEM MAY DROP INTO THE AREA FROM THE
NORTHWEST ON SUNDAY...SO WILL CONTINUE WITH CHANCE POPS FOR LIGHT
RAIN ON SUNDAY...AND LIGHT MIXED PRECIPITATION SUNDAY NIGHT. HEIGHTS
EXPECTED TO RISE BY EARLY NEXT WEEK WITH AN UPPER RIDGE BUILDING
IN...SO WILL GO DRY ON MONDAY AND TUESDAY.
&&
.AVIATION /DISCUSSION FOR THE 29/2100Z TAF UPDATE/...
UPDATE...
NO CHANGES
PREVIOUS DISCUSSION...
APPEARS BROAD SURFACE FRONT WILL WORK IT/S WAY ACROSS THE REST OF
CENTRAL INDIANA THROUGH 19Z THIS AFTERNOON. NOT EXPECTING MUCH IN
THE WAY OF ACTIVITY WITH THIS FEATURE DUE TO WEAK LOW LEVEL
CONVERGENCE AND GENERAL DOWNWARD MOTION IN THE WAKE OF UPPER SYSTEM.
MODEL SOUNDINGS STILL CALLING FOR MFVR CEILINGS WITH THIS BUT THIS
SO FAR HAS NOT MATERIALIZED OVER THE AREA AND SO WILL GO WITH A
CLEAR TO MOSTLY CLEAR FORECAST.
SURFACE WIND GUSTS AROUND 35 KTS FROM W WILL CONTINUE THROUGH THIS
EVENING. MAY HAVE SOME MFVR CEILINGS DEVELOP EARLY THU MORNING FOR
KLAF AS AN UPPER LOW PUSHES EASTWARD ACROSS LWR MICHIGAN.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 7 PM EST THIS EVENING FOR INZ021-028>031-
035>049-051>057-060>065-067>072.
&&
$$
SYNOPSIS...PUMA
NEAR TERM...NIELD
SHORT TERM...PUMA
LONG TERM....JAS
AVIATION...SMF/TDUD
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1143 AM EST WED FEB 29 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
STRONG LOW PRESSURE OVER EASTERN NEBRASKA WILL PUSH TO
THE GREAT LAKES TONIGHT...DRAGGING A WARM FRONT ACROSS CENTRAL
INDIANA THIS MORNING AND A COLD FRONT ACROSS THE STATE TONIGHT.
THIS WILL BRING A ROUND OF SHOWERS AND THUNDERSTORMS TO CENTRAL
INDIANA THIS MORNING...ALONG WITH CHANCES THIS AFTERNOON.
FURTHERMORE A WINDY DAY IS EXPECTED AS A STRONG PRESSURE GRADIENT
IS EXPECTED.
DRY WEATHER WILL RETURN TONIGHT AND THURSDAY AS HIGH PRESSURE
MOVES THROUGH THE AREA. YET ANOTHER STORM SYSTEM WILL PUSH THROUGH
THE AREA ON FRIDAY AND THIS WILL BRING MORE CHANCES FOR SHOWERS
AND THUNDERSTORMS TO THE AREA.
A WEAKER SYSTEM WILL BRING CHANCES FOR PRECIPITATION ON
SUNDAY.
WELL ABOVE AVERAGE TEMPERATURES WILL CONTINUE FOR THE REMAINDER OF
THE WORK WEEK BEFORE NEAR AVERAGE READINGS RETURN FOR THE WEEKEND.
&&
.NEAR TERM /REST OF TODAY/...
MAIN ISSUE FOR THE MORNING UPDATE IS THE REMOVAL OF POPS FOR MOST
OF THE AREA FOR THE REST OF THE DAY AS THE DRY SLOT QUICKLY WORKS
INTO THE AREA. DID HOLD ONTO THE LOW CHANCES OF THUNDER IN THE FAR
SOUTHEAST THIS AFTERNOON AS THE RUC HINTS AT SOME DEVELOPMENT
BEGINNING THERE AND PROGRESSING EASTWARD LATER TODAY.
SKIES ARE OR WILL BECOME SUNNY ACROSS MOST OF THE FORECAST AREA
WITHIN THE NEXT FEW HOURS...AND SHOULD REMAIN SO FOR THE REMAINDER
OF THE AFTERNOON. CLOUDINESS UNDER THE CORE OF THE UPPER LOW MAY
IMPINGE UPON THE NORTHWEST FORECAST AREA BY LATE THIS
AFTERNOON/EARLY IN THE EVENING.
WIND ADVISORY STILL LOOKS GOOD FOR THE AFTERNOON...WITH FORECAST
SOUNDINGS CONTINUING TO INDICATE WINDS NEAR THE TOP OF THE MIXED
LAYER OF 40 PLUS KNOTS. GUSTS TO 40-45 MPH...PERHAPS EVEN
APPROACHING 50 MPH IN THE NORTHWEST...LOOK LIKELY THIS AFTERNOON.
MINOR TWEAKS ALSO REQUIRED TO TEMPS...BUT NOTHING SIGNIFICANT.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...
MODELS ARE IN PRETTY GOOD AGREEMENT DURING THIS PERIOD AND WILL
USE A BLEND.
TONIGHT THE STRONG LOW PRESSURE SYSTEM OVER THE GREAT LAKES
WILL PULL NORTHEAST AS STRONG SUBSIDENCE TAKES SHAPE AS RIDGING
BUILDS ACROSS INDIANA FROM THE CENTRAL PLAINS. FORECAST SOUNDINGS
REMAIN DRY AND ALTHOUGH A FEW STRATOCU COULD LINGER IN THE COLD
AIR ADVECTION AND BROAD CYCLONIC FLOW...SKIES SHOULD REMAIN JUST
PTCLDY TO CLEAR. GOOD MIXING DUE TO THE STILL PRESENT PRESSURE
GRADIENT IS EXPECTED TO CONTINUE OVERNIGHT...WHICH MAY OFFSET
RADIATIONAL COOLING EFFECTS. THUS WILL STICK CLOSE TO MAVMOS FOR LOWS.
MORE DRY WEATHER IS EXPECTED ON THURSDAY AND THURSDAY NIGHT AS
RIDGING BUILDS ACROSS THE REGION ALOFT. TIME HEIGHT SECTIONS AND
FORECAST SOUNDINGS REMAIN UNSATURATED...THUS MOSTLY CLEAR SKIES
ARE EXPECTED THURSDAY. STRONG WARM AIR ADVECTION ONCE AGAIN BEGINS TO TAKE
SHAPE ON THURSDAY NIGHT AS ANOTHER LOW PRESSURE SYSTEM BEGIN TO
SPIN UP OVER THE CENTRAL PLAINS. THIS SHOULD RESULT IN CREASING
MID AND HIGH CLOUDS. WILL TRENDS HIGHS ON THURSDAY AND LOWS ON
THURSDAY NIGHT WARMER THAN MAVMOS.
ANOTHER UPPER TROUGH IS EXPECTED TO PUSH OUT OF THE PLAINS STATES
ON FRIDAY AND FRIDAY NIGHT. WITH GOOD SUPPORT ALOFT AND VERY GOOD
WARM ADVECTION AHEAD OF A COLD FRONT...SHOWERS AND THUNDERSTORMS
ARE ONCE AGAIN EXPECTED TO BREAK OUT. FORECAST SOUNDINGS BY 00Z
SAT INDICATE CONVECTIVE TEMPERATURES THAT WILL EASILY BE REACHED
ALONG WITH A MOIST AIR MASS IN PLACE. THUS WILL TREND BEST CHANCES
DURING THE AFTERNOON AND EVENING HOURS AS THE COLD FRONT PASSES.
AS FOR TEMPS...PLENTY OF HEATING HOURS SHOULD BE AVAILABLE ON
FRIDAY AND WILL LEAN WARMER THAN MAVMOS. WITH THE COLD FRONTAL
PASSAGE AND STRONG COLD AIR ADVECTION ON FRIDAY NIGHT WILL TREND
FRIDAY NIGHT LOWS COLDER THAN MEXMOS.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
ENSEMBLE DATA INDICATE A DEEP UPPER TROUGH WILL BE MOVING EAST FROM
THE MIDWEST ON SATURDAY TO A POSITION OFF THE EAST COAST BY EARLY
NEXT WEEK. A FEW ENSEMBLES STILL INDICATE POTENTIAL FOR LIGHT QPF ON
SATURDAY UNDER THE UPPER TROUGH...BUT STILL NOT ENOUGH TO WARRANT A
POP ON SATURDAY. A WEAK SYSTEM MAY DROP INTO THE AREA FROM THE
NORTHWEST ON SUNDAY...SO WILL CONTINUE WITH CHANCE POPS FOR LIGHT
RAIN ON SUNDAY...AND LIGHT MIXED PRECIPITATION SUNDAY NIGHT. HEIGHTS
EXPECTED TO RISE BY EARLY NEXT WEEK WITH AN UPPER RIDGE BUILDING
IN...SO WILL GO DRY ON MONDAY AND TUESDAY.
&&
.AVIATION /DISCUSSION FOR THE 291800Z TAFS/...
APPEARS BROAD SURFACE FRONT WILL WORK IT/S WAY ACROSS THE REST OF
CENTRAL INDIANA THROUGH 19Z THIS AFTERNOON. NOT EXPECTING MUCH IN
THE WAY OF ACTIVITY WITH THIS FEATURE DUE TO WEAK LOW LEVEL
CONVERGENCE AND GENERAL DOWNWARD MOTION IN THE WAKE OF UPPER SYSTEM.
MODEL SOUNDINGS STILL CALLING FOR MFVR CEILINGS WITH THIS BUT THIS
SO FAR HAS NOT MATERIALIZED OVER THE AREA AND SO WILL GO WITH A
CLEAR TO MOSTLY CLEAR FORECAST.
SURFACE WIND GUSTS AROUND 35 KTS FROM W WILL CONTINUE THROUGH THIS
EVENING. MAY HAVE SOME MFVR CEILINGS DEVELOP EARLY THU MORNING FOR
KLAF AS AN UPPER LOW PUSHES EASTWARD ACROSS LWR MICHIGAN.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 7 PM EST THIS EVENING FOR INZ021-028>031-
035>049-051>057-060>065-067>072.
&&
$$
SYNOPSIS...PUMA
NEAR TERM...NIELD
SHORT TERM...PUMA
LONG TERM....JAS
AVIATION...SMF
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1050 AM EST WED FEB 29 2012
.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
STRONG LOW PRESSURE OVER EASTERN NEBRASKA WILL PUSH TO
THE GREAT LAKES TONIGHT...DRAGGING A WARM FRONT ACROSS CENTRAL
INDIANA THIS MORNING AND A COLD FRONT ACROSS THE STATE TONIGHT.
THIS WILL BRING A ROUND OF SHOWERS AND THUNDERSTORMS TO CENTRAL
INDIANA THIS MORNING...ALONG WITH CHANCES THIS AFTERNOON.
FURTHERMORE A WINDY DAY IS EXPECTED AS A STRONG PRESSURE GRADIENT
IS EXPECTED.
DRY WEATHER WILL RETURN TONIGHT AND THURSDAY AS HIGH PRESSURE
MOVES THROUGH THE AREA. YET ANOTHER STORM SYSTEM WILL PUSH THROUGH
THE AREA ON FRIDAY AND THIS WILL BRING MORE CHANCES FOR SHOWERS
AND THUNDERSTORMS TO THE AREA.
A WEAKER SYSTEM WILL BRING CHANCES FOR PRECIPITATION ON
SUNDAY.
WELL ABOVE AVERAGE TEMPERATURES WILL CONTINUE FOR THE REMAINDER OF
THE WORK WEEK BEFORE NEAR AVERAGE READINGS RETURN FOR THE WEEKEND.
&&
.NEAR TERM /REST OF TODAY/...
MAIN ISSUE FOR THE MORNING UPDATE IS THE REMOVAL OF POPS FOR MOST
OF THE AREA FOR THE REST OF THE DAY AS THE DRY SLOT QUICKLY WORKS
INTO THE AREA. DID HOLD ONTO THE LOW CHANCES OF THUNDER IN THE FAR
SOUTHEAST THIS AFTERNOON AS THE RUC HINTS AT SOME DEVELOPMENT
BEGINNING THERE AND PROGRESSING EASTWARD LATER TODAY.
SKIES ARE OR WILL BECOME SUNNY ACROSS MOST OF THE FORECAST AREA
WITHIN THE NEXT FEW HOURS...AND SHOULD REMAIN SO FOR THE REMAINDER
OF THE AFTERNOON. CLOUDINESS UNDER THE CORE OF THE UPPER LOW MAY
IMPINGE UPON THE NORTHWEST FORECAST AREA BY LATE THIS
AFTERNOON/EARLY IN THE EVENING.
WIND ADVISORY STILL LOOKS GOOD FOR THE AFTERNOON...WITH FORECAST
SOUNDINGS CONTINUING TO INDICATE WINDS NEAR THE TOP OF THE MIXED
LAYER OF 40 PLUS KNOTS. GUSTS TO 40-45 MPH...PERHAPS EVEN
APPROACHING 50 MPH IN THE NORTHWEST...LOOK LIKELY THIS AFTERNOON.
MINOR TWEAKS ALSO REQUIRED TO TEMPS...BUT NOTHING SIGNIFICANT.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...
MODELS ARE IN PRETTY GOOD AGREEMENT DURING THIS PERIOD AND WILL
USE A BLEND.
TONIGHT THE STRONG LOW PRESSURE SYSTEM OVER THE GREAT LAKES
WILL PULL NORTHEAST AS STRONG SUBSIDENCE TAKES SHAPE AS RIDGING
BUILDS ACROSS INDIANA FROM THE CENTRAL PLAINS. FORECAST SOUNDINGS
REMAIN DRY AND ALTHOUGH A FEW STRATOCU COULD LINGER IN THE COLD
AIR ADVECTION AND BROAD CYCLONIC FLOW...SKIES SHOULD REMAIN JUST
PTCLDY TO CLEAR. GOOD MIXING DUE TO THE STILL PRESENT PRESSURE
GRADIENT IS EXPECTED TO CONTINUE OVERNIGHT...WHICH MAY OFFSET
RADIATIONAL COOLING EFFECTS. THUS WILL STICK CLOSE TO MAVMOS FOR LOWS.
MORE DRY WEATHER IS EXPECTED ON THURSDAY AND THURSDAY NIGHT AS
RIDGING BUILDS ACROSS THE REGION ALOFT. TIME HEIGHT SECTIONS AND
FORECAST SOUNDINGS REMAIN UNSATURATED...THUS MOSTLY CLEAR SKIES
ARE EXPECTED THURSDAY. STRONG WARM AIR ADVECTION ONCE AGAIN BEGINS TO TAKE
SHAPE ON THURSDAY NIGHT AS ANOTHER LOW PRESSURE SYSTEM BEGIN TO
SPIN UP OVER THE CENTRAL PLAINS. THIS SHOULD RESULT IN CREASING
MID AND HIGH CLOUDS. WILL TRENDS HIGHS ON THURSDAY AND LOWS ON
THURSDAY NIGHT WARMER THAN MAVMOS.
ANOTHER UPPER TROUGH IS EXPECTED TO PUSH OUT OF THE PLAINS STATES
ON FRIDAY AND FRIDAY NIGHT. WITH GOOD SUPPORT ALOFT AND VERY GOOD
WARM ADVECTION AHEAD OF A COLD FRONT...SHOWERS AND THUNDERSTORMS
ARE ONCE AGAIN EXPECTED TO BREAK OUT. FORECAST SOUNDINGS BY 00Z
SAT INDICATE CONVECTIVE TEMPERATURES THAT WILL EASILY BE REACHED
ALONG WITH A MOIST AIR MASS IN PLACE. THUS WILL TREND BEST CHANCES
DURING THE AFTERNOON AND EVENING HOURS AS THE COLD FRONT PASSES.
AS FOR TEMPS...PLENTY OF HEATING HOURS SHOULD BE AVAILABLE ON
FRIDAY AND WILL LEAN WARMER THAN MAVMOS. WITH THE COLD FRONTAL
PASSAGE AND STRONG COLD AIR ADVECTION ON FRIDAY NIGHT WILL TREND
FRIDAY NIGHT LOWS COLDER THAN MEXMOS.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
ENSEMBLE DATA INDICATE A DEEP UPPER TROUGH WILL BE MOVING EAST FROM
THE MIDWEST ON SATURDAY TO A POSITION OFF THE EAST COAST BY EARLY
NEXT WEEK. A FEW ENSEMBLES STILL INDICATE POTENTIAL FOR LIGHT QPF ON
SATURDAY UNDER THE UPPER TROUGH...BUT STILL NOT ENOUGH TO WARRANT A
POP ON SATURDAY. A WEAK SYSTEM MAY DROP INTO THE AREA FROM THE
NORTHWEST ON SUNDAY...SO WILL CONTINUE WITH CHANCE POPS FOR LIGHT
RAIN ON SUNDAY...AND LIGHT MIXED PRECIPITATION SUNDAY NIGHT. HEIGHTS
EXPECTED TO RISE BY EARLY NEXT WEEK WITH AN UPPER RIDGE BUILDING
IN...SO WILL GO DRY ON MONDAY AND TUESDAY.
&&
.AVIATION /DISCUSSION FOR THE 291200Z TAFS/...
1350Z UPDATE...NOT REALLY SEEING THE MFVR MATERIALIZING UPSTREAM
AND THINKING ABOUT REMOVING IT FROM THE TAFS. PREVIOUS DISC FOLLOWS...
LINE OF SHOWERS/THUNDERSTORMS ASSOCIATED WITH THE UPPER TROUGH
CURRENTLY PUSHING THROUGH EASTERN ILLINOIS. EXTRAPOLATION OF
FEATURE SUGGESTS IT SHOULD BE EAST OF KHUF/KLAF AROUND ISSUANCE
TIME...AND EAST OF KIND/KBMG BY 291300Z. THINK CONVECTIVE THREAT
WILL REMAIN RATHER HIGH UNTIL THIS FEATURE PASSES...AS SHORT TERM
MODEL DATA SHOW GOOD ELEVATED INSTABILITY AHEAD OF FEATURE ALONG
WITH 60-65 KT LOW LEVEL JET OVERHEAD.
APPEARS BROAD SURFACE FRONT LAGS A FEW HOURS BEHIND UPPER SYSTEM.
AT THIS POINT...DON/T EXPECT TOO MUCH ACTIVITY TO DEVELOP ALONG
ACTUAL FRONT DUE TO WEAK LOW LEVEL CONVERGENCE AND GENERAL
DOWNWARD MOTION IN THE WAKE OF UPPER SYSTEM. WILL HOLD ONTO MVFR
CEILINGS UNTIL FRONTAL PASSAGE FROM LATE MORNING UNTIL AROUND
MIDDAY...WITH CEILINGS SCATTERING OUT AFTER THAT.
GOOD POTENTIAL FOR SURFACE WIND GUSTS AROUND 35 KTS FROM 230-250
HEADINGS TO DEVELOP TOWARDS MIDDAY AS MID LEVEL JET MOVES OVERHEAD.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 7 PM EST THIS EVENING FOR INZ021-028>031-
035>049-051>057-060>065-067>072.
&&
$$
SYNOPSIS...PUMA
NEAR TERM...NIELD
SHORT TERM...PUMA
LONG TERM....JAS
AVIATION...JAS/SMF
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
333 AM CST WED FEB 29 2012
.SYNOPSIS...
WATER VAPOR IMAGERY IN CONJUNCTION WITH LATEST RUC PROGS SHOW A
CLOSED H5 LOW OVER SERN SD WITH A NEGATIVELY TILTED TROF EXTENDING
SOUTHEAST THROUGH IA AND CENTRAL IL. AT THE SURFACE DEEP LOW
PRESSURE WAS OVER NW IA WITH AN OCCLUDED FRONT EXTENDING SE
THROUGH CENTRAL IA. A WARM FRONT BRANCHED OFF TO THE EAST INTO IL
AND THE COLD FRONT ARCED SOUTH AND WEST THROUGH MO. THE MAIN AREA
OF TSRA AHEAD OF THE SYSTEM WAS JUST EXITING THE EASTERN CWFA AT
09Z. ANOTHER SHORT LINE OF SHRA/ISOLD TSRA HAD RECENTLY DEVELOPED
NORTH OF THE OCCLUSION IN CENTRAL IA AND WAS LIFTING NORTHEAST
THROUGH THE FAR NW CORNER OF THE CWFA. TEMPERATURES IN THE LOW 50S
WERE AS FAR NORTH AS I80 ALONG AND EAST OF THE MS. READINGS WERE
STILL AROUND 40 OVER THE NORTHERN.
&&
.SHORT TERM...TODAY AND TONIGHT...
THE STACKED SYSTEM WILL TRACK EAST ALONG THE IA/MN BORDER TODAY
AND THEN ON INTO SWRN ONTARIO BY THURSDAY MORNING. HIGH PRESSURE
WILL FILL IN BEHIND THE STORM WITH A SURFACE RIDGE EXPECTED TO
MOVE INTO CENTRAL IA BY THURSDAY MORNING.
FOR TODAY ALL OF THE SHRA/TSRA WILL BE OUT OF THE FORECAST AREA AND
CLEARING VIA THE DRY SLOT SHOULD SPREAD OVER THE SOUTHERN HALF OF
THE CWFA BY 12Z. WITH THE STRONG PRESSURE GRADIENT AROUND THE
SURFACE LOW AND MORNING SUN THE SOUTHERN HALF OF THE AREA SHOULD
BE ABLE TO MIX OUT FAIRLY DEEP...AT LEAST TO 800MB...BEFORE WRAP
AROUND ST SAGS SOUTH OVER THE AREA BY LATE MORNING OR EARLY
AFTERNOON. MODELS SOUNDINGS SHOW THE DEEP MIXING WILL BE ABLE TO
TAP WINDS OF 45 TO 50KTS DURING THE AFTERNOON. WITH LITTLE
DIRECTIONAL CHANGE IN THE MIXED LAYER THERE SHOULD BE EFFICIENT
MOMENTUM TRANSPORT TO THE SURFACE CAUSING WINDS TO GUST 40 TO 50
MPH LATE THIS MORNING AND THIS AFTERNOON. EXPECT AREAS SOUTH OF
I80 TO HAVE THE STRONGEST WINDS. LESS HEATING AND THICKER CLOUD
COVER OVER NORTHEAST SHOULD KEEP GUSTS FROM EXCEEDING ADVISORY
CRITERIA. THEREFORE...NO CHANGES ARE PLANNED FOR THE CURRENT
ADVISORY. IN ADDITION TO THE WIND ISSUES SOME SCATTERED RAIN
AND/OR SNOW SHOWERS WILL REDEVELOP OVER THE NRN HALF OF THE AREA
WITH THE RAIN CLOSE TO HIGHWAY 30 AND THE SNOWSHOWERS ALONG THE
HIGHWAY 20 CORRIDOR. THE PRECIP WILL BE LIGHT AND LITTLE IF ANY
SNOW ACCUMULATION IS EXPECTED. SINCE THE SHOWERS WILL BE TIED TO
INSTABILITY FROM DAYTIME HEATING...THEY SHOULD DISSIPATE BY EARLY
THIS EVENING. TEMPERATURES IN THE NORTH SHOULDN/T RISE MUCH TODAY
WITH CLOUDS OVER AREA THROUGH THE DAY. IN THE SOUTH READINGS
SHOULD REBOUND TO AROUND 50 WITH SOME MORNING SUN AND THE DEEPER
MIXING.
TONIGHT WITH THE STORM MOVING AWAY FROM THE REGION THE LOW LEVEL
CYCLONIC FLOW WILL WEAKEN AND SUBSIDENCE SHOULD BE ABLE TO EAT
AWAY AT THE WRAP AROUND ST OVER THE WESTERN AND SOUTHERN CWFA. THE
NORTHEAST MAY HOLD ON TO CLOUDS THROUGH 12Z. LOWS TONIGHT AROUND
30 LOOK REASONABLE.
.LONG TERM...THURSDAY THROUGH NEXT TUESDAY...
QUIET AND DRY CONDITIONS WILL BE SEEN THURSDAY AS HIGH PRESSURE
MOVES THROUGH THE AREA. THURSDAY NIGHT...THE MODELS BRING AN INITIAL
WAVE OF LOW PRESSURE THROUGH THE AREA ALONG A FRONT/BOUNDARY.
INTERESTINGLY...SEVERAL OF THE MODELS ARE BREAKING OUT LIGHT QPF
OVER THE NORTHERN HALF OF THE CWFA. INTERNALLY...FORCING IS
GENERALLY WEAK...MOISTURE IS LACKING...AND CONDENSATION PRESSURE
DEFICITS REMAIN FAIRLY HIGH. MOISTURE/SPEED CONVERGENCE CAN BE
IMPLIED BY THE INVERTED TROF BUT INTERNALLY THE MODELS GENERALLY
HAVE EITHER NO CONVERGENCE OR IT MOVES NORTH/EAST OF THE CWFA.
THE INVERTED TROF IS THE MOST TROUBLING AS THEY ARE NOTORIOUS FOR
SURPRISES. SO...AFTER WEIGHING THE OPTIONS HAVE OPTED TO GO WITH
SCHC POPS OVER ROUGHLY THE NORTHERN THIRD WHICH CONCEPTUALLY IS THE
MOST LIKELY AREA TO SEE ANY PRECIP. PTYPE SHOULD BE SPRINKLES OR A
VERY LIGHT RAIN AS WET BULB TEMPERATURES ARE ABOVE FREEZING AT THE
SFC AND AT 0.5KM.
THE MAIN WAVE OF ENERGY ARRIVES ON FRIDAY. BASED ON THE OVERALL
FORCING THE SOUTHEAST HALF OF THE CWFA HAS THE BETTER CHANCES FOR
PRECIPITATION. WET BULB TEMPERATURES SLOWLY FALL DURING THE DAY SO
THE PRECIPITATION WILL INITIALLY START OUT AS RAIN. BY MID TO LATE
FRIDAY AFTERNOON WET BULB TEMPERATURES DROP ENOUGH AT 0.5KM THAT A
RAIN/SNOW MIX SHOULD DEVELOP OVER THE NORTHWEST THIRD TO HALF OF THE
CWFA. A RAIN/SNOW MIX SHOULD BE SEEN ACROSS MOST OF THE CWFA FRIDAY
EVENING WITH PRECIPITATION ENDING AFTER MIDNIGHT.
SATURDAY ON...
MODEL CONSENSUS GIVE DRY CONDITIONS ON SATURDAY AHEAD OF AN
APPROACHING CLIPPER SYSTEM. SATURDAY NIGHT/SUNDAY THE CONSENSUS GIVE
SCHC POPS OVER THE NORTHEAST THIRD TO HALF OF THE CWFA. RIGHT NOW
THIS LOOKS REASONABLE GIVEN MOISTURE AVAILABILITY AND THE OVERALL
DISAGREEMENT ON TIMING. HOWEVER...GIVEN THE OVERALL SYNOPTIC SETUP
THESE POPS ARE PROBABLY TOO LOW.
MODEL CONSENSUS GIVES DRY CONDITIONS SUNDAY NIGHT THROUGH TUESDAY AS
HEIGHTS BUILD OVER THE MID CONUS AHEAD OF SHORTWAVE ENERGY ARRIVING
IN THE PAC NW. STRONG SOUTHERLY FLOW IS PROGGED TO DEVELOP AHEAD OF
ANOTHER STORM SYSTEM IN THE NORTHERN PLAINS MONDAY AND TUESDAY. THE
MODELS ARE LIKELY UNDER ESTIMATING THE SURGE OF WARM AIR COMING
NORTH BASED ON THE OVERALL SYNOPTIC SET UP. TEMPERATURES TUESDAY
SHOULD BE WELL ABOVE NORMAL AND POTENTIALLY HIGHER THAN WHAT THE
MODELS CURRENTLY SUGGEST.
..08..
&&
.AVIATION ISSUED AT 1138PM CST TUE FEB 28 2012...
A STRONG STORM SYSTEM MOVING INTO SOUTHERN MINNESOTA WILL BRING
RAIN AND SCATTERED THUNDERSTORMS ACROSS THE FORECAST TERMINALS
UNTIL 10Z. GENERALLY MVFR CONDITIONS DUE TO LOW CLOUDS BASES OF
1-3K AGL ARE EXPECTED UNTIL A COLD FRONT PASSES BETWEEN 11-14Z
WHEN VFR CONDITIONS RETURN. THE POTENTIAL FOR THUNDERSTORMS THE
NEXT SEVERAL HOURS IS TOO REMOTE AT ANY GIVEN SITE TO MENTION
BEYOND USE OF CB WORDING. SOUTHEAST WINDS OF 15 TO 25 KTS WILL
SHIFT TO THE WEST SOUTHWEST AND INCREASE TO 25 TO 35 KTS WITH SOME
HIGHER GUSTS TO 40 KTS BETWEEN 15-23Z. LOW CLOUDS WILL RETURN FROM
NORTH TO SOUTH AT ALL TERMINALS BETWEEN 20-24Z WITH SNOW SHOWERS
POSSIBLE AT CID AND DBQ. WINDS WILL SLIGHTLY DECREASE TO 20 TO 30
KTS AFTER SUNSET. ..NICHOLS..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...WIND ADVISORY FROM 9 AM THIS MORNING TO 6 PM CST THIS EVENING
FOR BENTON-BUCHANAN-CEDAR-CLINTON-DELAWARE-DES MOINES-HENRY
IA-IOWA-JEFFERSON-JOHNSON-JONES-KEOKUK-LEE-LINN-LOUISA-
MUSCATINE-SCOTT-VAN BUREN-WASHINGTON.
IL...WIND ADVISORY FROM 9 AM THIS MORNING TO 6 PM CST THIS EVENING
FOR BUREAU-HANCOCK-HENDERSON-HENRY IL-MCDONOUGH-MERCER-
PUTNAM-ROCK ISLAND-WARREN-WHITESIDE.
MO...WIND ADVISORY FROM 9 AM THIS MORNING TO 6 PM CST THIS EVENING
FOR CLARK-SCOTLAND.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
647 PM MST THU MAR 1 2012
.UPDATE...
ISSUED AT 644 PM MST THU MAR 1 2012
BAND OF LIGHT SNOW HAS DEVELOPED ACROSS SOUTHERN PORTIONS OF KIT
CARSON COUNTY COLORADO STRETCHING EASTWARD THEN NORTHEASTWARD INTO
NORTHWEST KANSAS. KITR HAD A BRIEF PERIOD OF 3/4 MILE VISIBILITY
IN LIGHT SNOW WITH THAT PORTION OF THE BAND NOW SHIFTING EASTWARD
INTO SOUTHWEST PORTIONS OF SHERMAN COUNTY. ANOTHER AREA OF
ENHANCED REFLECTIVITY RESIDES OVER SOUTHWEST KIT CARSON COUNTY AND
CONTINUES TO SHIFT EASTWARD WITH TIME. PRIMARY CHANGES WERE TO
SPEED UP ONSET OF PRECIP ACROSS NORTHWEST KANSAS. ALSO MADE
SIGNIFICANT ADJUSTMENTS TO THE DEW POINT GRIDS AS TOP DOWN
MOISTENING HAS RESULTED IN DEW POINTS JUMPING INTO THE LOWER TO
MIDDLE 20S WHERE PRECIP IS FALLING.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 200 PM MST THU MAR 1 2012
A COLD FRONT THAT PASSED OVER THE CWA EARLY THIS MORNING IS NOW
ACROSS SOUTHWEST KANSAS AND SOUTHEAST COLORADO. EARLY AFTERNOON WV
IMAGERY AND RUC H5 ANALYSIS SHOW A BROAD TROUGH ACROSS THE WESTERN
US. A STRENGTHENING SHORTWAVE TROUGHS IS CURRENTLY MOVING INTO
WESTERN COLORADO.
TONIGHT THROUGH FRIDAY...SHORTWAVE TROUGH WILL MOVE OUT OF COLORADO
INTO WESTERN KANSAS. MOISTURE/LIFT WILL INCREASE FROM THE WET TO THE
EAST THIS EVENING AHEAD OF THIS FEATURE...WITH BEST LIFT/MOISTURE IN
THE 03-09Z TIMEFRAME. RAIN WILL QUICKLY TRANSITION TO SNOW IN THE
WEST THIS EVENING...WITH A RAIN/SNOW MIX IN THE EAST MOST OF THE
NIGHT. BY SUNRISE MOST LOCATIONS SHOULD SEE RAIN COMPLETELY
TRANSITION TO SNOW. GUIDANCE HAS TRENDED FURTHER SOUTH AND WEST ON
PLACEMENT OF HIGHEST SNOWFALL AMOUNTS...WHICH MAKES SENSE
CONSIDERING THE LOCATION OF SURFACE BAROCLINIC ZONE. WITH THIS IS
MIND...I INCREASED POPS ACROSS THE SOUTHWEST...AND DECREASED POPS IN
THE NORTHEAST. CONSIDERING THE LIMITED MOISTURE ADVECTION...AND
QUICK NATURE OF THIS SYSTEM...SNOWFALL AMOUNTS SHOULD REMAIN LIGHT.
RIGHT NOW HIGHEST AMOUNTS SHOULD BE LIMITED TO EASTERN COLORADO
WHERE 1-2 INCHES IS EXPECTED.
WITH LARGE SCALE SUBSIDENCE BUILDING BACK OVER THE CWA FRIDAY
MORNING FROM THE NORTH...PRECIPITATION SHOULD TAPER OFF QUICKLY FROM
THE NORTH TO THE SOUTH BY MID FRIDAY MORNING OVER ALL BUT THE
EXTREME SOUTHWEST PARTS OF THE CWA. DRY CONDITIONS ARE THEN EXPECTED
THROUGH FRIDAY AFTERNOON ACROSS ALL OF THE CWA.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 200 PM MST THU MAR 1 2012
MAIN WEATHER STORY FOR THE LONG TERM IS A WARMING TREND AS LARGE
UPPER RIDGE ALBEIT SOMEWHAT FLAT DEVELOPS OVER THE AREA. HIGH
TEMPERATURE SATURDAY IN THE 40S WILL WARM INTO THE 50S AND LOW 60S
SUNDAY. EVEN WARMER ON MONDAY WITH MID TO UPPER 60S AND MID 60S TO
LOW 70S TUESDAY.
TIMING DIFFERENCES SHOW UP WEDNESDAY AND THURSDAY AS THE WEST
COAST UPPER TROUGH MOVES TOWARD OR ACROSS THE AREA...IMPACTING THE
TEMPERATURE FORECAST. LOOKS TO REMAIN ABOVE NORMAL BOTH DAYS WITH
HIGHS IN THE 50S.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 438 PM MST THU MAR 1 2012
MID-LEVEL CLOUD DECK CONTINUES TO DEVELOP ACROSS THE TRI-STATE
REGION WITH UPSTREAM CIGS GENERALLY REMAINING VFR. RADAR ECHOS
EXPANDING OVER THE PAST HOUR BUT LITTLE PRECIP ACTUALLY REACHING
THE GROUND. ANTICIPATE THIS WILL CHANGE FOR KGLD BY AROUND 03Z
WITH MVFR CIGS DEVELOPING IN -SN. COULD BE A PERIOD OF LOW MVFR/IFR CIGS
IN LIGHT SNOW AT KGLD PRIMARILY BETWEEN 05Z AND 07Z WITH
CONDITIONS IMPROVING BACK TO VFR AROUND 08Z AND REMAINING THERE
THROUGH THE END OF THE EFFECTIVE PERIOD.
FOR KMCK...ANTICIPATE PREVAILING VFR CIGS THROUGH THE PERIOD WITH
A POTENTIAL FOR A PERIOD OF MVFR CIGS BETWEEN 05Z AND 08Z. DON`T
HAVE A HIGH CONFIDENCE IN PRECIP SO NO PLANS TO INCLUDE FOR THIS
ISSUANCE.
&&
.FIRE WEATHER...
ISSUED AT 200 PM MST THU MAR 1 2012
CRITICAL FIRE WEATHER CONDITIONS REMAIN POSSIBLE ALONG AND SOUTH
OF INTERSTATE 70 SATURDAY AS NORTHWEST WINDS OF 15 TO 25 MPH WITH
HIGHER GUSTS COMBINE WITH AFTERNOON HUMIDITY AS LOW AS 20 PERCENT.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
KS...NONE.
NE...NONE.
&&
$$
UPDATE...FOLTZ
SHORT TERM...DR
LONG TERM....007
AVIATION...FOLTZ
AREA FORECAST DISCUSSION
NWS GOODLAND KS
453 PM MST THU MAR 1 2012
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 200 PM MST THU MAR 1 2012
A COLD FRONT THAT PASSED OVER THE CWA EARLY THIS MORNING IS NOW
ACROSS SOUTHWEST KANSAS AND SOUTHEAST COLORADO. EARLY AFTERNOON WV
IMAGERY AND RUC H5 ANALYSIS SHOW A BROAD TROUGH ACROSS THE WESTERN
US. A STRENGTHENING SHORTWAVE TROUGHS IS CURRENTLY MOVING INTO
WESTERN COLORADO.
TONIGHT THROUGH FRIDAY...SHORTWAVE TROUGH WILL MOVE OUT OF COLORADO
INTO WESTERN KANSAS. MOISTURE/LIFT WILL INCREASE FROM THE WET TO THE
EAST THIS EVENING AHEAD OF THIS FEATURE...WITH BEST LIFT/MOISTURE IN
THE 03-09Z TIMEFRAME. RAIN WILL QUICKLY TRANSITION TO SNOW IN THE
WEST THIS EVENING...WITH A RAIN/SNOW MIX IN THE EAST MOST OF THE
NIGHT. BY SUNRISE MOST LOCATIONS SHOULD SEE RAIN COMPLETELY
TRANSITION TO SNOW. GUIDANCE HAS TRENDED FURTHER SOUTH AND WEST ON
PLACEMENT OF HIGHEST SNOWFALL AMOUNTS...WHICH MAKES SENSE
CONSIDERING THE LOCATION OF SURFACE BAROCLINIC ZONE. WITH THIS IS
MIND...I INCREASED POPS ACROSS THE SOUTHWEST...AND DECREASED POPS IN
THE NORTHEAST. CONSIDERING THE LIMITED MOISTURE ADVECTION...AND
QUICK NATURE OF THIS SYSTEM...SNOWFALL AMOUNTS SHOULD REMAIN LIGHT.
RIGHT NOW HIGHEST AMOUNTS SHOULD BE LIMITED TO EASTERN COLORADO
WHERE 1-2 INCHES IS EXPECTED.
WITH LARGE SCALE SUBSIDENCE BUILDING BACK OVER THE CWA FRIDAY
MORNING FROM THE NORTH...PRECIPITATION SHOULD TAPER OFF QUICKLY FROM
THE NORTH TO THE SOUTH BY MID FRIDAY MORNING OVER ALL BUT THE
EXTREME SOUTHWEST PARTS OF THE CWA. DRY CONDITIONS ARE THEN EXPECTED
THROUGH FRIDAY AFTERNOON ACROSS ALL OF THE CWA.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 200 PM MST THU MAR 1 2012
MAIN WEATHER STORY FOR THE LONG TERM IS A WARMING TREND AS LARGE
UPPER RIDGE ALBEIT SOMEWHAT FLAT DEVELOPS OVER THE AREA. HIGH
TEMPERATURE SATURDAY IN THE 40S WILL WARM INTO THE 50S AND LOW 60S
SUNDAY. EVEN WARMER ON MONDAY WITH MID TO UPPER 60S AND MID 60S TO
LOW 70S TUESDAY.
TIMING DIFFERENCES SHOW UP WEDNESDAY AND THURSDAY AS THE WEST
COAST UPPER TROUGH MOVES TOWARD OR ACROSS THE AREA...IMPACTING THE
TEMPERATURE FORECAST. LOOKS TO REMAIN ABOVE NORMAL BOTH DAYS WITH
HIGHS IN THE 50S.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 438 PM MST THU MAR 1 2012
MID-LEVEL CLOUD DECK CONTINUES TO DEVELOP ACROSS THE TRI-STATE
REGION WITH UPSTREAM CIGS GENERALLY REMAINING VFR. RADAR ECHOS
EXPANDING OVER THE PAST HOUR BUT LITTLE PRECIP ACTUALLY REACHING
THE GROUND. ANTICIPATE THIS WILL CHANGE FOR KGLD BY AROUND 03Z
WITH MVFR CIGS DEVELOPING IN -SN. COULD BE A PERIOD OF LOW MVFR/IFR CIGS
IN LIGHT SNOW AT KGLD PRIMARILY BETWEEN 05Z AND 07Z WITH
CONDITIONS IMPROVING BACK TO VFR AROUND 08Z AND REMAINING THERE
THROUGH THE END OF THE EFFECTIVE PERIOD.
FOR KMCK...ANTICIPATE PREVAILING VFR CIGS THROUGH THE PERIOD WITH
A POTENTIAL FOR A PERIOD OF MVFR CIGS BETWEEN 05Z AND 08Z. DON`T
HAVE A HIGH CONFIDENCE IN PRECIP SO NO PLANS TO INCLUDE FOR THIS
ISSUANCE.
&&
.FIRE WEATHER...
ISSUED AT 200 PM MST THU MAR 1 2012
CRITICAL FIRE WEATHER CONDITIONS REMAIN POSSIBLE ALONG AND SOUTH
OF INTERSTATE 70 SATURDAY AS NORTHWEST WINDS OF 15 TO 25 MPH WITH
HIGHER GUSTS COMBINE WITH AFTERNOON HUMIDITY AS LOW AS 20 PERCENT.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
KS...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM....007
AVIATION...FOLTZ
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1258 AM EST WED FEB 29 2012
.Update...
Update#2
Issued at 945 PM EST Feb 28 2012
A line of thunderstorms has developed across southeast MO and
southern IL. Timing of this line brings it into the western portion
of the forecast area around 05Z. Mesoscale models continue to
develop more convection overnight as the low level jet ramps up.
Have made only minor adjustments to the ongoing forecast.
Update#1
Issued at 630 PM EST Feb 28 2012
The latest runs of the HRRR and the Rapid Refresh are indicating a
bit later start to the precipitation this evening. Currently there
is nothing much on radar close to the forecast area. Will therefore
take out/lower pops before the 05-06Z time frame. Temperatures are
also running quite a bit warmer than hourlies so will update to
bring them in line. Updates will be out soon.
.Short Term (Tonight through Wednesday night)...
Updated at 200 PM EST Feb 28 2012
...Heavy rain/strong storms tonight with potential for severe storms
tomorrow...
The much anticipated storm system that will affect us in the short
term is currently developing over Nebraska, with it`s warm front and
60+ dewpoints slowly filtering northward across the southern CONUS,
and it`s cold front just downstream of the Rockies. Looks like with
the 12z runs of the mesoscale models, think precipitation will come
in two main waves. First, with the warm-air advection/elevated
showers/storms overnight ahead of the warm front. And second, along
of and just ahead of the cold front tomorrow afternoon.
Tonight, clouds and moisture will be on the increase tonight as the
surface low develops and moves towards the Upper Midwest overnight.
This will help draw the warm front from southwest to northeast
across our County Warning Area (CWA), mainly from the 07-13z time
frame. Showers and thunderstorms should develop along the nose of a
65-70 kt low-level jet, which will overspread north of and ahead of
the warm front from SW to NE across the CWA. However, best moisture
convergence seems to be across our northwest CWA after 06z, so think
convection will be rather scattered from 00-06z tonight, and will
blow up ahead of the warm front, mainly hugging the Ohio River and
into north-central Kentucky from 06-12z. At this time, our far
southwestern CWA could see surface-based warm-sector air, but not
sure any of the convection will be that far south to be rooted in
the boundary layer air. Thus, think the severe chances tonight are
fairly slim. However, if storms do lag into central and even
south-central KY in the morning (4-8am CST), these will likely be
surface-based, and a severe threat would be possible, with damaging
winds and possibly an isolated tornado threat but think that is slim
right now. These storms look more like heavy rainers, possibly
hailers, and ample lightning. And again, think the concentration
will mainly be across the central part of the CWA northward or
northwestward.
Then after daybreak, warm-air advection convection should more north
of the CWA, with the entire CWA getting rooted into the boundary
layer/warm-sector air. Not sure we`ll see a break in the low
strato-cu, but it is possible. If breaks occur, much of the
low-level jet winds will mix down, creating ample gusty winds
tomorrow. Think sustained winds of 20-25 mph will be possible with
gusts as high as 40 mph, close to wind advisory criteria. May defer
that to the next forecast tonight. Either way, we`ll be sectored in
the warm, moist, gusty air ahead of the quickly approaching cold
front. Progged soundings show ample deep-layer shear, and strong
speed shear in the low-levels. Deep moisture along the cold front
however will be much lower than the overnight moisture, so think a
few storms will erupt along the cold front, but not a large, thick
line of convection. However, any storm that develops along the cold
front has the potential to become quickly supercellular, with
damaging winds, hail and isolated tornadoes being potential threats.
Best chance for this would be east of I-65 after noon tomorrow.
There will still be a severe weather threat along the cold front
west of I-65 as well, but the best heating and longer time to
recover from morning convection will happen over the eastern CWA.
So overall, looks like the best chance for severe weather will be a
small window over our southwestern CWA after 4am CST late tonight,
but a better chance mainly along and east of I-65 tomorrow
afternoon. Behind the cold frontal passage, winds will veer around
to the west and continue to be gusty until Wednesday night where
they will taper off.
Lowered precipitation in the grids to account for the break between
late night/early morning warm frontal convection and the lesser
amount but more significant strong-severe convection tomorrow
midday-afternoon.
Concerning temps, lows will drop off early tonight and then increase
towards 12z with the warm front pushing northward. Tomorrow, despite
mostly cloudy conditions, temperatures will still be able to rise
into the 60s and even lower 70s over the south/southeast.
.Long Term (Thursday - Tuesday)...
Updated at 315 PM EST Feb 28 2012
...Potential for more strong to severe thunderstorms again Friday
afternoon and night...
Another potent storm system on Friday is the main concern in the
extended forecast. Before that occurs, however, Thursday will be a
tranquil weather day between systems. Surface high pressure over the
Ohio Valley and Southeast will ensure a mostly sunny day, and
temperatures will remain mild with afternoon highs generally in the
lower and mid 60s.
The high will move off to our east quickly Thursday night as a
deepening trough aloft takes shape over the western United States
and begins moving east. The trough will cause CYCLOGENESIS across
the southern high Plains Thursday night. The surface low pressure
center will then deepen quite rapidly as it moves northeast into the
mid
Mississippi Valley Friday and Great Lakes Friday night. Ahead of
this low, low-level moisture should return rapidly. Last night`s and
the newest 12z model runs suggest an area of precipitation will
quickly develop Thursday night over the Tennessee Valley in a warm
advection/isentropic lift zone. Elevated instability returning from
the southern Plains suggests that thunder will be embedded within
the area of rain. This precipitation may make it into south-central
KY by Friday morning, then lift quickly northeast into eastern KY in
the afternoon.
The main concern is Friday afternoon and evening, according to the
latest model timing. Wind fields increase throughout the lower and
mid levels, while actually decent instability is forecast to develop
in the warm sector between the departing warm front and east of a
potent cold front, which will extend south from the low pressure
center. Given cold frontal forcing, wind fields, and instability,
strong to severe storms could develop over parts of the Ohio Valley
extending south into the Tennessee Valley and lower Mississippi
Valley/southeastern United States. This system will need to be
watched closely.
Much cooler weather will move in for the weekend. The strong cyclone
mentioned above will move north of the Great lakes, with possibly a
surface pressure under 980mb. It parent 500mb trough will be
absorbed by a strengthening polar vortex near Hudson`s Bay. By early
Sunday, ridging will strengthen over the Rockies with troughing over
the Great Lakes. Expect a partly cloudy sky Saturday with brisk west
winds developing during the afternoon. Highs Saturday will remain in
the lower to mid 50s. A weak clipper will scoot southeast from the
Upper Missouri Valley Saturday and traverse the Commonwealth on
Sunday. Cloud cover will increase Sunday with just a slight chance
of showers. Highs Sunday will have a hard time reaching 50.
In a slowly progressive pattern, 500mb ridging will move east across
the central plains on Monday. After partly cloudy, cool day Monday
with high pressure nearly overhead, southwest winds will commence
Tuesday, beginning a warmup.
&&
.Aviation (06Z TAF Issuance)...
Updated at 1225 AM EST Feb 29 2012
Warm front just south of KSDF at this hour. Have some thunderstorms
riding north of that boundary and otherwise look like we have more
airmass type showers that may spark off some thunder as the plenty
of moisture streams in from the southwest. So far the near-surface
air has not been moist enough to produce much in the way of vsby
restrictions, except in the heaviest storms. Have backed off on the
prevailing storm conditions and tried to time the first 6 hours of
this TAF based on radar. After that expect a brief dry period before
another round of storms comes in closer to a cold front later this
morning into the afternoon.
With regard to winds, should have low-level shear through around
daybreak at all of the sites. After daybreak, surface winds will
become gusty from the southwest, with peak gusts of 25-35 kts. May
even get some higher values if we get enough sunshine to mix higher
up.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Update...........EER
Short Term.......AL
Long Term........JSD
Aviation.........EER
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
124 PM EST WED FEB 29 2012
.SYNOPSIS...
A LOW PRESSURE SYSTEM, FROM IOWA, PASSING NORTHEASTWARD THROUGH THE
GREAT LAKES, WILL PROVIDE THE UPPER OHIO VALLEY WITH SHOWERS AND
SCATTERED THUNDERSTORMS INTO TONIGHT.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE MAIN BODY OF RAIN ASSOCIATED WITH THE WARM FRONT HAS PUSHED
EAST OF THE DISTRICT. ADDITIONAL SHOWERS AND SCATTERED
THUNDERSTORMS ARE EXPECTED TO FORM THIS AFTERNOON AHEAD OF THE
APPROACHING COLD FRONT. SOME OF THESE STORMS WILL CONTAIN HEAVY
DOWNPOURS ESPECIALLY IN THE SOUTHERN PORTIONS OF THE WARNING AREA.
A FLASH FLOOD WATCH HAS BEEN ISSUED FOR WEST VIRGINIA SOUTH OF THE
MASON DIXON LINE UNTIL 11PM. AN ADDITIONAL INCH OF RAIN IN THREE HOURS
OR LESS WILL BRING STREAMS AND CREEKS OUT OF THEIR BANKS.
THE SURFACE LAYER WILL BECOME WELL MIXED, THIS AFTERNOON AS CLOUDS BEGIN
TO BREAK. SCATTERED SHOWERS AND THUNDERSTORMS CAN GENERATE GUSTY
SURFACE WINDS. MOST OF EASTERN OHIO AND THE REMAINDER OF THE
FORECAST AREA FROM PITTSBURGH SOUTH REMAINS IN A SLIGHT RISK OF
SEVERE THUNDERSTORMS FOR THIS AFTERNOON INTO THIS EVENING.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
RECENT SREF AND WRF-NMM MODEL OUTPUT CONTINUES TO PROJECT THE
SYSTEM`S COLD FRONT TO PASS THROUGH THE AREA LATE TONIGHT. COLD
ADVECTION IN THE WAKE OF THE FRONT DAYTIME THURSDAY MAY DEEPEN THE
MIXING LAYER SUFFICIENTLY FOR SOME RAIN AND ISOLATED SNOW SHOWERS
OVER AREAS NORTH OF PITTSBURGH.
SHORTWAVE RIDGE WILL PROVIDE A DRY BREAK THURSDAY NIGHT. A WELL
DEVELOPED LOW PRESSURE SYSTEM, MOVING NORTHEAST FROM OKLAHOMA TO
MICHIGAN, MORE MOISTURE...AND WARMER TEMPERATURES TOWARD THE AREA ON
FRIDAY, WITH POSSIBLY SHOWERS LATE.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
THAT LOW PRESSURE IS FORECAST TO PUSH ANOTHER COLD FRONT ACROSS THE
UPPER OHIO VALLEY DURING FRIDAY NIGHT AND EARLY SATURDAY.
POST FRONTAL NORTHWEST FLOW SUPPORTS A COOL DOWN WITH A MIX OF RAIN
AND SNOW SHOWERS POSSIBLE SATURDAY NIGHT AND SUNDAY. THE ENSUING
BROAD RIDGE SHOULD PROMOTE DRY CONDITIONS AND MODERATING
TEMPERATURES MONDAY AND TUESDAY.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
PER BLEND OF RECENT RADAR, SURFACE, AND LIGHTNING DATA, COUPLED
WITH HRRR AND NAM MODEL OUTPUT, EXPECT MAINLY MVFR RAIN THIS
MORNING WITH THE WARM FRONTAL PASSAGE, WITH INTERLUDES OF IFR POSSIBLE,
PARTICULARLY IN HEAVIER RAIN AND POSSIBLE THUNDERSTORMS.
NAM MODEL PROFILES SHOW A STABLE SURFACE LAYER WITH WINDS NEAR 40
KTS AT 2 KFT AGL. HENCE HAVE MAINTAINED A FORECAST OF LOW LEVEL WIND
SHEAR 14Z-20Z, DESPITE AN UNSTABLE LAYER ALOFT THAT CAN FACILITATE
THUNDERSTORM DEVELOPMENT.
THE PRE-COLD-FRONTAL WARM SECTOR, WILL THEN PROMOTE VERTICAL MIXING WITHIN
THE SURFACE LAYER, WHICH SHOULD YIELD AN IMPROVEMENT IN CEILINGS AND
VISIBILITIES, ALBEIT STILL POSSIBLY IN THE MVFR RANGE.
HOWEVER, WINDS CAN GUST OVER 20 KTS. SPC HAS SUGGESTED THUNDERSTORMS
CAN ALSO FORM IN THE PERIOD 18Z-01Z, AND HAS INCLUDED A SLIGHT RISK
OF SEVERE ACROSS THE SOUTH, WITH WIND THE MAIN HAZARD.
CONDITIONS MAY IMPROVE TO VFR AFTER THE COLD FRONTAL PASSAGE LATE
TONIGHT.
OUTLOOK...THURSDAY THROUGH SUNDAY...
GENERALLY VFR THURSDAY INTO FRIDAY, ALTHOUGH RESTRICTIONS MAY BE
POSSIBLE NORTH DAYTIME THURSDAY WITH MIXED SHOWERS.
RESTRICTIONS AND SHOWERS ARE POSSIBLE AGAIN FRIDAY NIGHT AND THROUGH
THE WEEKEND, AS ANOTHER LOW PUSHES A COLD FRONT THROUGH THE AREA.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...FLASH FLOOD WATCH UNTIL 11 PM EST THIS EVENING FOR MDZ001.
OH...NONE.
PA...NONE.
WV...FLASH FLOOD WATCH UNTIL 11 PM EST THIS EVENING FOR WVZ012-
021>023-041.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
951 AM EST WED FEB 29 2012
.SYNOPSIS...
A LOW PRESSURE SYSTEM, FROM IOWA, PASSING NORTHEASTWARD THROUGH THE
GREAT LAKES, WILL PROVIDE THE UPPER OHIO VALLEY WITH SHOWERS AND
SCATTERED THUNDERSTORMS INTO TONIGHT.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AREA OF WIDESPREAD RAIN IS DIMINISHING FROM THE WEST AS UPPER LEVEL
SHORT WAVE MOVES RAPIDLY EAST ALONG THE WARM FRONT. WILL REDUCE POPS
FOR THE NEXT SEVERAL HOURS IN OHIO AS A RESULT. BLEND OF RECENT
RADAR AND SURFACE DATA COUPLED WITH RECENT HRRR AND WRF- NMM MODEL
OUTPUT SHOW SCATTERED THUNDERSTORMS EMBEDDED IN THIS RAIN SHIELD.
SO A CHANCE OF THUNDERSTORMS WILL BE INCLUDED IN THE ENTIRE FORECAST
AREA FOR THE REMAINDER OF THE DAY.
NAM MODEL PROFILES SHOW A STABLE SURFACE LAYER, SO INITIALLY THE
THUNDERSTORMS WOULD BE MORE THE ELEVATED KIND, ALTHOUGH LIGHTNING
DATA SHOWS SOME CLOUD TO GROUND STRIKES. HOWEVER, DURING THE AFTERNOON,
THE SURFACE LAYER BECOMES WELL MIXED, SO CONVECTION THEN, BE IT
SHOWERS OR THUNDERSTORMS, CAN GENERATE GUSTY SURFACE WINDS, AND
THIS APPEARS TO BE THE BASIS OF SPC`S SLIGHT RISK OF SEVERE
THUNDERSTORMS TODAY FOR SOUTHERN PARTS OF THE UPPER OHIO VALLEY.
FORECASTED TEMPERATURES CLOSE TO GFS MOS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
RECENT SREF AND WRF-NMM MODEL OUTPUT CONTINUES TO PROJECT THE
SYSTEM`S COLD FRONT TO PASS THROUGH THE AREA LATE TONIGHT. COLD
ADVECTION IN THE WAKE OF THE FRONT DAYTIME THURSDAY MAY DEEPEN THE
MIXING LAYER SUFFICIENTLY FOR SOME RAIN AND ISOLATED SNOW SHOWERS
OVER AREAS NORTH OF PITTSBURGH.
SHORTWAVE RIDGE WILL PROVIDE A DRY BREAK THURSDAY NIGHT. A WELL
DEVELOPED LOW PRESSURE SYSTEM, MOVING NORTHEAST FROM OKLAHOMA TO
MICHIGAN, MORE MOISTURE...AND WARMER TEMPERATURES TOWARD THE AREA ON
FRIDAY, WITH POSSIBLY SHOWERS LATE.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
THAT LOW PRESSURE IS FORECAST TO PUSH ANOTHER COLD FRONT ACROSS THE
UPPER OHIO VALLEY DURING FRIDAY NIGHT AND EARLY SATURDAY.
POST FRONTAL NORTHWEST FLOW SUPPORTS A COOL DOWN WITH A MIX OF RAIN
AND SNOW SHOWERS POSSIBLE SATURDAY NIGHT AND SUNDAY. THE ENSUING
BROAD RIDGE SHOULD PROMOTE DRY CONDITIONS AND MODERATING
TEMPERATURES MONDAY AND TUESDAY.
&&
.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
PER BLEND OF RECENT RADAR, SURFACE, AND LIGHTNING DATA, COUPLED
WITH HRRR AND NAM MODEL OUTPUT, EXPECT MAINLY MVFR RAIN THIS
MORNING WITH THE WARM FRONTAL PASSAGE, WITH INTERLUDES OF IFR POSSIBLE,
PARTICULARLY IN HEAVIER RAIN AND POSSIBLE THUNDERSTORMS.
NAM MODEL PROFILES SHOW A STABLE SURFACE LAYER WITH WINDS NEAR 40
KTS AT 2 KFT AGL. HENCE HAVE MAINTAINED A FORECAST OF LOW LEVEL WIND
SHEAR 14Z-20Z, DESPITE AN UNSTABLE LAYER ALOFT THAT CAN FACILITATE
THUNDERSTORM DEVELOPMENT.
THE PRE-COLD-FRONTAL WARM SECTOR, WILL THEN PROMOTE VERTICAL MIXING WITHIN
THE SURFACE LAYER, WHICH SHOULD YIELD AN IMPROVEMENT IN CEILINGS AND
VISIBILITIES, ALBEIT STILL POSSIBLY IN THE MVFR RANGE.
HOWEVER, WINDS CAN GUST OVER 20 KTS. SPC HAS SUGGESTED THUNDERSTORMS
CAN ALSO FORM IN THE PERIOD 18Z-01Z, AND HAS INCLUDED A SLIGHT RISK
OF SEVERE ACROSS THE SOUTH, WITH WIND THE MAIN HAZARD.
CONDITIONS MAY IMPROVE TO VFR AFTER THE COLD FRONTAL PASSAGE LATE
TONIGHT.
OUTLOOK...THURSDAY THROUGH SUNDAY...
GENERALLY VFR THURSDAY INTO FRIDAY, ALTHOUGH RESTRICTIONS MAY BE
POSSIBLE NORTH DAYTIME THURSDAY WITH MIXED SHOWERS.
RESTRICTIONS AND SHOWERS ARE POSSIBLE AGAIN FRIDAY NIGHT AND THROUGH
THE WEEKEND, AS ANOTHER LOW PUSHES A COLD FRONT THROUGH THE AREA.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
658 AM EST WED FEB 29 2012
.SYNOPSIS...
A LOW PRESSURE SYSTEM, FROM IOWA, PASSING NORTHEASTWARD THROUGH THE
GREAT LAKES, WILL PROVIDE THE UPPER OHIO VALLEY WITH SHOWERS AND
SCATTERED THUNDERSTORMS INTO TONIGHT.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
RECENT RADAR AND SURFACE DATA SHOW LIGHT RAIN, ASSOCIATED WITH THE
INCOMING LOW PRESSURE SYSTEM, SPREADING EASTWARD THROUGH THE UPPER
OHIO VALLEY. SURFACE DATA SHOWS TEMPERATURES ACROSS THE ENTIRE AREA
ARE WARMER THAN FREEZING AND DEW POINTS ARE RISING QUICKLY FROM THE
SOUTHWEST. BECAUSE OF THIS, HAVE CANCELLED THE FREEZING RAIN
ADVISORY.
BLEND OF RECENT RADAR AND SURFACE DATA COUPLED WITH RECENT HRRR
AND WRF-NMM MODEL OUTPUT SHOW SCATTERED THUNDERSTORMS EMBEDDED IN
THIS RAIN SHIELD. SO HAVE ADDED A CHANCE OF THUNDERSTORMS TO BE
SPREADING EASTWARD DURING TODAY. ADJUSTED RAIN AMOUNTS CLOSER TO
HPC AND RFC GUIDANCE.
NAM MODEL PROFILES SHOW A STABLE SURFACE LAYER, SO INITIALLY THE
THUNDERSTORMS WOULD BE MORE THE ELEVATED KIND, ALTHOUGH LIGHTNING
DATA SHOWS SOME CLOUD TO GROUND STRIKES. HOWEVER, DURING THE AFTERNOON,
THE SURFACE LAYER BECOMES WELL MIXED, SO CONVECTION THEN, BE IT
SHOWERS OR THUNDERSTORMS, CAN GENERATE GUSTY SURFACE WINDS, AND
THIS APPEARS TO BE THE BASIS OF SPC`S SLIGHT RISK OF SEVERE
THUNDERSTORMS TODAY FOR SOUTHERN PARTS OF THE UPPER OHIO VALLEY.
FORECASTED TEMPERATURES CLOSE TO GFS MOS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
RECENT SREF AND WRF-NMM MODEL OUTPUT CONTINUES TO PROJECT THE
SYSTEM`S COLD FRONT TO PASS THROUGH THE AREA LATE TONIGHT. COLD
ADVECTION IN THE WAKE OF THE FRONT DAYTIME THURSDAY MAY DEEPEN THE
MIXING LAYER SUFFICIENTLY FOR SOME RAIN AND ISOLATED SNOW SHOWERS
OVER AREAS NORTH OF PITTSBURGH.
SHORTWAVE RIDGE WILL PROVIDE A DRY BREAK THURSDAY NIGHT. A WELL
DEVELOPED LOW PRESSURE SYSTEM, MOVING NORTHEAST FROM OKLAHOMA TO
MICHIGAN, MORE MOISTURE...AND WARMER TEMPERATURES TOWARD THE AREA ON
FRIDAY, WITH POSSIBLY SHOWERS LATE.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
THAT LOW PRESSURE IS FORECAST TO PUSH ANOTHER COLD FRONT ACROSS THE
UPPER OHIO VALLEY DURING FRIDAY NIGHT AND EARLY SATURDAY.
POST FRONTAL NORTHWEST FLOW SUPPORTS A COOL DOWN WITH A MIX OF RAIN
AND SNOW SHOWERS POSSIBLE SATURDAY NIGHT AND SUNDAY. THE ENSUING
BROAD RIDGE SHOULD PROMOTE DRY CONDITIONS AND MODERATING
TEMPERATURES MONDAY AND TUESDAY.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
PER BLEND OF RECENT RADAR, SURFACE, AND LIGHTNING DATA, COUPLED
WITH HRRR AND NAM MODEL OUTPUT, EXPECT MAINLY MVFR RAIN THIS
MORNING WITH THE WARM FRONTAL PASSAGE, WITH INTERLUDES OF IFR POSSIBLE,
PARTICULARLY IN HEAVIER RAIN AND POSSIBLE THUNDERSTORMS.
NAM MODEL PROFILES SHOW A STABLE SURFACE LAYER WITH WINDS NEAR 40
KTS AT 2 KFT AGL. HENCE HAVE MAINTAINED A FORECAST OF LOW LEVEL WIND
SHEAR 14Z-20Z, DESPITE AN UNSTABLE LAYER ALOFT THAT CAN FACILITATE
THUNDERSTORM DEVELOPMENT.
THE PRE-COLD-FRONTAL WARM SECTOR, WILL THEN PROMOTE VERTICAL MIXING WITHIN
THE SURFACE LAYER, WHICH SHOULD YIELD AN IMPROVEMENT IN CEILINGS AND
VISIBILITIES, ALBEIT STILL POSSIBLY IN THE MVFR RANGE.
HOWEVER, WINDS CAN GUST OVER 20 KTS. SPC HAS SUGGESTED THUNDERSTORMS
CAN ALSO FORM IN THE PERIOD 18Z-01Z, AND HAS INCLUDED A SLIGHT RISK
OF SEVERE ACROSS THE SOUTH, WITH WIND THE MAIN HAZARD.
CONDITIONS MAY IMPROVE TO VFR AFTER THE COLD FRONTAL PASSAGE LATE
TONIGHT.
OUTLOOK...THURSDAY THROUGH SUNDAY...
GENERALLY VFR THURSDAY INTO FRIDAY, ALTHOUGH RESTRICTIONS MAY BE
POSSIBLE NORTH DAYTIME THURSDAY WITH MIXED SHOWERS.
RESTRICTIONS AND SHOWERS ARE POSSIBLE AGAIN FRIDAY NIGHT AND THROUGH
THE WEEKEND, AS ANOTHER LOW PUSHES A COLD FRONT THROUGH THE AREA.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
115 PM EST WED FEB 29 2012
.SYNOPSIS...
ISSUED AT 700 AM EST WED FEB 29 2012
AFTER DROPPING A FEW INCHES OF SNOW AND SLEET ACROSS NORTHERN LOWER
MICHIGAN...LOW PRESSURE WILL MOVE EAST TODAY WITH ONLY SCATTERED
SHOWERS AND DRIZZLE THIS AFTERNOON. COLDER AIR WILL MOVE IN TONIGHT
WITH SOME SNOW SHOWERS. AFTER A BREAK IN THE ACTION...ANOTHER STORM
WILL MOVE IN ON FRIDAY WITH RAIN CHANGING TO SNOW LATE FRIDAY NIGHT.
&&
.SHORT TERM...(THIS AFTERNOON THROUGH THURSDAY)
ISSUED AT 113 PM EST WED FEB 29 2012
DROPPED ALL THE ADVISORY BEFORE NOON...AS THE PRECIPITATION WAS
SWEEPING OUT OF THE AREA. DRY SLOT HAS SPREAD ACROSS THE ENTIRE
AREA AS OF 100PM...WITH CLEARING SWEEPING IN FROM THE SOUTHWEST.
ELIMINATED MOST OF THE POPS FOR THE AFTERNOON HOURS...OUTSIDE OF
SOME DRIZZLE POSSIBLE UP ON THE HIGH GROUND OF CENTRAL LOWER AND
SHOWERS TRYING TO PUSH BACK IN WITH THE UPPER LOW TOWARD 00Z.
MAIN FOCUS NOW WILL BE ON HOW FAR NORTH THE CLEARING AND WARMTH COMES.
PUSHED 50S INTO THE I94 ROW OF COUNTIES AND PARTIAL CLEARING ALL
THE WAY TO I96. WILL NEED TO KEEP AN EYE ON THIS THOUGH IS IT MAY
MAKE A RUN FURTHER NORTH INTO THE FORECAST AREAS. MODEL PROGS HOLD
CLOUDS IN FOR AREAS NORTH OF A MKG TO LAN LINE. GIVEN CURRENT
TRENDS ITS HARD NOT TO ENVISION THE CLEARING WORKING NORTH OF THAT
LINE...BUT AM GOING TO GIVE THE FORECAST A CHANCE AT THIS POINT
AND WILL UPDATE AS NECESSARY. WINDS IN THE CLEAR SLOT ARE A
CONCERN AS WELL WITH GUSTS ABOVE 30 KNOTS. LATEST RUC HAS THE
TRIPLE POINT AND WARM NOSE SLIDING ALONG I94...SO WILL LET THE
CURRENT FORECAST HOLD.
PREVIOUS DISCUSSION FOLLOWS...
THE ENTIRE AREA WILL SEE THICKER CLOUDS THEN MOVE IN LATE THIS
AFTERNOON AND EVENING AS THE WRAP AROUND MOISTURE AND COLD AIR
WITH THE MAIN LOW ROTATES ACROSS THE AREA. WE WILL SEE SHOWERS
ASSOCIATED WITH THE UPPER LOW ALSO MOVE IN. THE AIR WILL REMAIN
SUFFICIENTLY WARM ENOUGH UNTIL AROUND 03Z THAT ALL SHOWERS WILL
REMAIN RAIN. THAT WILL TRANSITION OVER TO SNOW FROM W TO E AFTER
03Z. WE COULD SEE A LIGHT ACCUMULATION OF SNOW...ESPECIALLY UP
NORTH CLOSER TO THE LOW AND ACROSS THE HIGHER TERRAIN UP NORTH.
THIS PCPN SHOULD MOVE OUT LATE WED NIGHT. SOME RESIDUAL FORCING
MAY BE LEFT IN THE LOWER ATMOSPHERE AS THE MID AND UPPER LEVEL
MOISTURE MOVES OUT. THIS COULD SET UP THE AREA FOR A CHC OF SOME
LIGHT DRIZZLE OR FREEZING DRIZZLE FOR A SHORT TIME TOWARD DAYBREAK
ON THU. THAT WILL MOVE OUT BY MID MORNING...AND ALLOW FOR A QUIET
DAY AS HIGH PRESSURE MOVES THROUGH THE AREA.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 413 AM EST WED FEB 29 2012
MAIN EVENT IN THE EXTENDED IS A DEEPENING LOW MOVING ACROSS THE LP
OF MICHIGAN ON FRIDAY. 00Z RUNS OF ECMWF AND GFS ARE IN EXCELLENT
AGREEMENT WITH THE TRACK AND STRENGTH OF THE LOW. LOOKS LIKE RAIN
FRIDAY CHANGING TO SNOW FRIDAY NIGHT WITH ONLY LIGHT ACCUMS IN THE
LAKE ENHANCED WRAP AROUND SNOW.
TWEAKED TEMPS DOWN A BIT OVER THE WEEKEND AS MODELS IN GOOD
AGREEMENT ON MINUS 10 TO 15C AT 850 MB MOVING SATURDAY AND SUNDAY.
MODELS ALSO IN GOOD AGREEMENT ON A CLIPPER MOVING THROUGH
SATURDAY NIGHT INTO SUNDAY...SO WENT ALONG WITH APX AND IWX IN
BUMPING UP POPS FOR SUNDAY. COULD BE SOME ACCUMS WITH THE CLIPPER
AND LAKE ENHANCEMENT IN WEST FLOW.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 113 PM EST WED FEB 29 2012
DIFFICULT SET OF TAF FORECASTS AT 18Z...WITH A CLEAR SLOT TRYING
TO MOVE ACROSS THE AREA. ALL SITES ARE LOCKED INTO IFR/LIFR AT
18Z...WITH CLEAR AND VFR NOT FAR OFF ON THE HORIZON. CLEARING HAS
PUSHED THROUGH BEH AND SBN AT 18Z...WITH BIV AND AZO NOT FAR
BEHIND. TRIED TO WORK THE CLEARING ACROSS THE I94 TAF SITES OF
AZO...BTL AND JXN THROUGH THE AFTERNOON...BUT THE NORTHERN SITES
WERE A TOUGHER CALL. THINK MKG WILL CLEAR FOR A WHILE AS
WELL...BUT HELD ON TO BROKEN IFR CLOUDS FOR GRR AND LAN.
CONFIDENCE IS LOW IN THIS THOUGH AND WILL NEED TO BE WATCHED AS
THE CLEARING IS SURGING NORTHEAST. THE COLDER GROUND AND LOW
SLIDING EAST MAY TRY TO KEEP THE CLOUDS IN AT GRR AND LAN WHICH IS
HOW THE FORECAST WAS WRITTEN.
WILL NEED TO KEEP A CLOSE EYE ON THE WINDS SWEEPING IN FROM THE
SOUTHWEST AS WELL AS GUSTS TO 35 KNOTS OR SO ARE OCCURRING BENEATH
THE CLEAR SKIES.
TONIGHT SNOW SHOWERS WILL SWEEP BACK IN WITH MVFR CEILINGS. THE
MVFR CONDITIONS SHOULD PERSIST THROUGH THE MORNING ON THURSDAY.
&&
.MARINE...
ISSUED AT 413 AM EST WED FEB 29 2012
WE WILL HOLD ON TO THE GALE WARNING FOR ALL OF THE NEARSHORE AREA.
WINDS AT THE COASTAL SITES APPEAR TO NOT BE REACHING GALE
CRITERIA. CRITERIA IS LIKELY BEING MET OFFSHORE DUE TO THE ERLY
FLOW. WINDS WILL DIMINISH SOME TODAY AS A FRONT MOVES THROUGH THE
AREA. WINDS WILL PICK UP ONCE AGAIN BEHIND THE FRONT LATE TODAY.
GALES WILL REMAIN POSSIBLE THROUGH THE FIRST HALF OF TONIGHT
BEFORE DIMINISHING.
&&
.HYDROLOGY...
ISSUED AT 413 AM EST WED FEB 29 2012
RIVERS ALL REMAIN WITHIN THEIR BANKS THIS MORNING WITH NO FLOOD
HEADLINES OUT FOR NOW. RAINFALL/LIQUID EQUIVALENT SHOULD END UP
WITH UP TO HALF AN INCH. SOME CONTINGENCY FORECASTS BY THE RFC
INDICATE WE COULD START SEEING SOME RIVER POINTS GO ABOVE
ACTION/ADVISORY STAGE. THIS SEEMS MORE LIKELY TO OCCUR AFTER THE
NEXT SYSTEM MOVES THROUGH ON FRIDAY WITH MORE RAINFALL LOOKING
LIKELY.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...GALE WARNING UNTIL 1 AM EST THURSDAY FOR LMZ844>849.
&&
$$
SYNOPSIS...NJJ
SHORT TERM...NJJ/DUKE
LONG TERM....OSTUNO
AVIATION...DUKE
MARINE...NJJ
HYDROLOGY...NJJ
AREA FORECAST DISCUSSION
NWS GAYLORD MI
1253 AM EST WED FEB 29 2012
.UPDATE...
ISSUED AT 1253 AM EST WED FEB 29 2012
NO MAJOR CHANGES NEEDED AT THIS EARLY HOUR. HAVE SPED UP THE
ARRIVAL TIME OF INITIAL BATCH OF MAINLY LIGHT SNOW PER RADAR
TRENDS...WITH SECONDARY HEAVIER BATCH OF PRECIP EXPECTED TO BEGIN
OVERTAKING THE CWA AFTER 09Z. GIVEN UPSTREAM OBS...HAVE ALSO
INTRODUCED MIXED PRECIP MENTION EARLIER ACROSS THE SOUTHWEST
COUNTIES. UPSTREAM RADAR PICS OVER GREEN BAY HAVE A MIXED
PRECIP/CELLULAR APPEARANCE TO THEM...IN LINE WITH LATEST RUC PROGS
BRINGING IN A PRONOUNCED WARM NOSE UP TO +3C INTO THE SOUTHWEST
COUNTIES ROUGHLY 09-10Z. WILL CUT BACK SNOWFALL TOTALS DOWN THAT
WAY A BIT (MAINLY 1-2 INCHES)...BUT HAVE ALSO RAISED AMOUNTS
ACROSS THE HIGHER TERRAIN AREAS WHERE UPSLOPE COMPONENT SHOULD
KEEP COLDER AIR LOCKED IN LONGER THROUGH MID MORNING. CURRENT
HEADLINES LOOK JUST FINE...BUT WILL HAVE TO WATCH PRECIP TYPE AS
HEAVY AXIS OF QPF ARRIVES THROUGH MID MORNING. IF TYPE REMAINS
ALL SNOW...CAN FORESEE THE NEED TO EXPAND THE WARNING MORE INTO
NORTHWEST LOWER BETWEEN M-72 AND M-32. HOWEVER...CONCERNED THAT
WARM NOSE WILL ARRIVE IN THOSE AREAS QUICKLY AS IS TYPICAL IN
THESE SITUATIONS...CUTTING INTO SNOWFALL AMOUNTS. ALL IN ALL...NO
MATTER THE SPECIFICS...IT WILL BE A MESSY MORNING COMMUTE IN MANY
AREAS SOUTH OF THE BRIDGE.
UPDATE ISSUED AT 1035 PM EST TUE FEB 28 2012
HAVE UPGRADED SOME COUNTIES IN NORTHERN LOWER MICHIGAN TO A
WARNING.
LOW PRESSURE NOW ADVANCING THROUGH EASTERN IOWA AHEAD OF A VERY
VIGOROUS UPPER LEVEL SHORT WAVE EJECTING NORTHEASTWARD FROM THE
CENTRAL PLAINS. VERY STRONG PULSE OF WARM ADVECTION FORCING/MOISTURE
FEED STARTING TO TAP THE GULF LEADING TO TO A LARGE EXPANDING
SHIELD OF PRECIP FROM ILLINOIS UP ACROSS WISCONSIN/MINNESOTA AND
THE DAKOTAS. STRONG CONVECTION BREAKING OUT IN THE CENTRAL PLAINS.
PRETTY MUCH YOUR TYPICAL STRONG SPRING STORM.
ACROSS THE REGION...A PRETTY HEFTY BATCH OF SNOWFALL HAS ALREADY
BLOSSOMED OVER SRN/ERN WISCONSIN THIS EVENING AND ABOUT TO WORK
INTO THE SW PART OF THIS CWA. BUT THE STRONGEST FORCING IS YET TO
ARRIVE...
OVERNIGHT...LOW PRESSURE SYSTEM WILL OCCLUDE OVER THE
IOWA/MINNESOTA REGION OVER THE NEXT SEVERAL HOURS. AS THIS
OCCURS...VERY STRONG PULSE OF WARM ADVECTION FORCING AND
ASSOCIATED WING OF PRECIP WILL ADVANCE UP THROUGH LOWER MICHIGAN
OVERNIGHT AND UP INTO EASTERN UPPER MICHIGAN WEDNESDAY
MORNING...FOLLOWED BY A SHARP DRY PUNCH OF AIR WORKING THROUGH THE
CWA DURING THE AFTERNOON. PRETTY MUCH IN LINE WITH PREVIOUS
FORECAST THINKING.
INITIALLY...WAS SKEPTICAL OF NAM/GFS QPF AMOUNTS APPROACHING ONE
INCH BY WEDNESDAY EVENING WITH THIS STORM...ESPECIALLY GIVEN THAT
BULK OF PRECIP WILL ONLY LAST AROUND 6 HOURS BEFORE TAPERING OFF
SHARPLY TO DRIZZLE/FREEZING DRIZZLE WITHIN THE DRY SLOT DURING THE
AFTERNOON HOURS. HOWEVER...MODEL N-S CROSS SECTIONS ACROSS LOWER
MICHIGAN HAVE CHANGED MY MIND. VERY IMPRESSIVE F-GEN DEVELOPS
ACROSS THE REGION WEDNESDAY MORNING WITHIN THE SHARPLY CYCLONIC
FLOW AND VERY STRONG WIND CORE THAT WORKS UP THROUGH THE REGION.
RESULTING OMEGA BULLSEYE IS IMPRESSIVE...MAXIMIZING IN THE DGZ
RIGHT UP ACROSS NRN LOWER MICHIGAN FOR A TIME WEDNESDAY MORNING.
TERRAIN AND A STRONG SE LOW LEVEL FLOW WILL LIKELY HELP THE CAUSE
OVER NE AND NORTH CENTRAL LOWER MICHIGAN AS WELL.
GIVEN THAT...AND A SLIGHTLY SLOWER TREND IN THE 00Z GUIDANCE SUGGESTING
MORE PRECIP OVER NRN LOWER MICHIGAN...HAVE EXPANDED WARNING DOWN
TWO TIER OF COUNTIES IN NRN LOWER MICHIGAN. HAVE TENTATIVELY LEFT
OUT CHARLEVOIX/ANTRIM COUNTIES AS DOWNSLOPING SE FLOW MAY KEEP PRECIP
IN CHECK...WILL SEE. STILL NOT CONVINCED WE SEE AN INCH OF LIQUID
WITH THIS SYSTEM. BUT EVEN IF WE GET CLOSE...ACCUMULATIONS IN THE
4 TO 7 INCH RANGE CERTAINLY VERY POSSIBLE OVER PORTIONS OF NE
LOWER MICHIGAN.
PRECIP TYPE ISSUES REMAIN WITH THIS SYSTEM...AS ABOVE FREEZING
WARM NOSE SURGES UP INTO NRN LOWER MICHIGAN ON WEDNESDAY.
BUT...TIMING IS EVERYTHING...AND BULK OF PRECIP ACROSS THE CWA
WILL BE LARGELY OVER BEFORE THE WARM NOSE ARRIVES. SO AT THIS
POINT...AM NOT TOO CONCERNED ABOUT SIGNIFICANT ICING OR PRECIP
CHANGING TO RAIN...AT LEAST DURING THE HEAVIEST PART OF THE EVENT.
UPDATE ISSUED AT 732 PM EST TUE FEB 28 2012
JUST MINOR TWEAKS TO THE FORECAST AT THIS POINT. HAVE RE-TOOLED
POPS/WEATHER FOR THIS EVENING THAT ADDRESSES THIS INITIAL CORRIDOR
OF LIGHT SNOW...WAY OUT AHEAD OF THE MAIN SHOW. INITIAL BATCH OF
LIGHT SNOW DRIVING ALONG BY ENTRANCE REGION UPPER JET FORCING AND
INITIAL PULSE OF WARM ADVECTION ALOFT...AND WON/T AMOUNT TO MUCH
THIS EVENING.
HOWEVER...BIGGER SURGE OF MID LEVEL WARM ADVECTION FORCING AND
ADVANCING MID LEVEL THETA-E GRADIENT ALREADY LEADING TO EXPANDING
AREA OF HEAVIER SNOWFALL ACROSS SRN WISCONSIN. THIS INITIAL BATCH
OF SNOWFALL WILL REACH THE SW PART OF THIS CWA BY LATE EVENING...
BUT MAY BE WEAKENING AS IT DOES SO. BOTTOM LINE...MAY HAVE TO
SPEED UP ARRIVAL OF CATEGORICAL SNOWFALL INTO THOSE SW COUNTIES IF
CURRENT TRENDS HOLD.
&&
.SYNOPSIS...
ISSUED AT 359 PM EST TUE FEB 28 2012
A LOW PRESSURE SYSTEM OVER THE CENTRAL PLAINS WILL CONTINUE TO
ADVANCE TOWARDS NORTHERN MICHIGAN...GENERATING A WINTRY MIX OF
PRECIPITATION WHICH WILL BEGIN LATE TONIGHT...AND LAST THROUGH
WEDNESDAY NIGHT...WITH HEAVY SNOW EXPECTED OVER THE UPPER
PENINSULA. AFTER A BRIEF BREAK THURSDAY AS AN AREA OF HIGH
PRESSURE BUILDS OVER THE REGION...ANOTHER LOW PRESSURE SYSTEM WILL
START TO TAKE SHAPE IN THE WESTERN GREAT LAKES ON FRIDAY.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 359 PM EST TUE FEB 28 2012
TOP DOWN SATURATION ONGOING OVER THE FORECAST AREA WITH SNOW ALREADY
HAVING REACHING THE GROUND FROM BEAVER ISLAND EAST TO MACKINAC
ISLAND. THIS SNOW HAS DEVELOPED LESS IN RESPONSE TO OUR UPCOMING
WEATHER-MAKER...AND MORE IN-LINE WITH THE RIGHT ENTRANCE REGION OF A
H25 JET MAX THAT EXTENDS FROM LAKE SUPERIOR SOUTH AND EAST INTO
SOUTHERN ONTARIO...AS WELL AS A WEAK PV ANOMALY SEEN IN WATER VAPOR
IMAGERY NOW JUST NORTH EAST OF LAKE SUPERIOR AND RACING EAST. THESE
FEATURES...COMBINED WITH STRENGTHENING UPSTREAM WARM ADVECTION IN
ADVANCE OF EJECTING FOUR CORNERS SHORTWAVE HAS HELPED CONSOLIDATE A
BAND OF MID LEVEL FRONTOGENESIS...WITH JUST ENOUGH MOISTURE FOR SNOW
TO REACH THE GROUND. ANYTHING THROUGH THIS EVENING SHOULD BE PRETTY
LIGHT...HOWEVER...AND AS THE AFOREMENTIONED SHORTWAVE PUSHES
EAST...WE WILL LIKELY SEE THIS ACTIVITY DRY UP SOME WITH PERHAPS
JUST A FEW FLURRIES OVER NORTHWEST LOWER AND THE STRAITS REGION WITH
STRENGTHENING DRY LOW LEVEL SOUTHEASTERLY FLOW HELPING ERODE ANY
MOISTURE. EARLY AFTERNOON HRRR IS IN GOOD AGREEMENT WITH THESE
TRENDS.
A WINTER WEATHER MESS IS SET TO ARRIVE LATE TONIGHT COURTESY OF THE
AFOREMENTIONED SHORTWAVE EJECTING OUT OF THE SOUTHWESTERN
STATES...BEING KICKED NORTH AND EAST BY ARRIVING ENERGY ALONG THE
PACIFIC COAST. MODEL INITIALIZATION WAS GENERALLY GOOD AT 12UTC
WITH ANY ERRORS NOT ENOUGH TO PRODUCE SIGNIFICANT DIFFERENCES IN
FORECASTS FROM THE NAM/GFS/ECMWF. THE TREND OVER THE PAST 24 HOURS
OF A MORE ROBUST AND NORTHERN SOLUTION TO THE SURFACE LOW HAS ENDED
WITH ALL GUIDANCE SHOWING A SLIGHT SOUTHWARD SHIFT IN THEIR 12Z
SOLUTIONS WITH GOOD CLUSTERING OF THE GEFS AROUND THE GFS AND THE
09Z SREF CLOSE TO THE 12Z NAM. THIS BRINGS LOW PRESSURE NORTHEAST
ACROSS THE CENTRAL PLAINS TO A POSITION OVER SOUTHWEST MINNESOTA BY
DAYBREAK WEDNESDAY /NEAR 990 MB/ WITH A LOW TRACK THAT THEN MOVES
JUST ABOUT DUE EAST AS THE SYSTEM OCCLUDES. IN TERMS OF PATTERN
RECOGNITION...H7 LOW TRACK MOVES EAST ACROSS NORTHERN LOWER SOMETIME
WEDNESDAY NIGHT...SUGGESTING THE BEST CHANCES FOR PROLONGED SNOWS
WILL BE FROM THE TIP OF THE MITT NORTH.
OUR WEATHER-MAKER WILL HAVE AMPLE MOISTURE TO WORK WITH AS THE GULF
WAS WIDE OPEN AS OF 12UTC WITH H85 DEWPOINTS AT OR ABOVE 10C
STREAMING NORTH ACROSS TX/OK/AK/LA. THE RESULT OF STRENGTHENING
MOISTURE ADVECTION WILL BE 1" PWATS MAKING A RUN AT THE SOUTHERN
GREAT LAKES TONIGHT.
TONIGHT...BAND OF STRONG ISENTROPIC ASCENT ON THE I290 SURFACE WILL
SPREAD NORTH AS THE AFOREMENTIONED STREAM OF MOISTURE PUSHES NORTH.
PRIMARY FORECAST CONCERN TONIGHT RESIDES AROUND PRECIPITATION START
TIME...AS DRY LOW LEVEL SOUTHEASTERLY FLOW ATTEMPTS TO ERODE
MOISTURE AS IT ARRIVES. THERE HAS BEEN A NOTICEABLE TREND TO SLOW
PRECIPITATION ONSET TIME WITH THE 12UTC GUIDANCE...WHICH IS VERY
REASONABLE GIVEN THE SETUP. HAVE ADJUSTED POPS FOR THIS
REASON...WHICH SHOULD KEEP PRECIPITATION SOUTH OF THE BRIDGE THROUGH
DAYBREAK. FURTHER SOUTH...A SWATH OF MODERATE TO POTENTIALLY HEAVY
PRECIPITATION WILL ARRIVE FROM SOUTHWEST TO NORTHEAST. WITHIN THIS
BAND...INGREDIENTS LOOK GOOD FOR SOME BANDED HEAVY SNOW POTENTIAL...
WITH OMEGA BULLS-EYED NEAR OR AT OR JUST ABOVE THE CENTER OF THE DGZ
WITH REDUCED EPV ALOFT AS STRONG WARM ADVECTION REDUCES MID LEVEL
LAPSE RATES. PRECIPITATION TYPE ISSUES WILL ENSUE QUICKLY BEHIND
INITIAL EDGE OF SNOWFALL AS WETBULB ZERO LINE AT H85 ARRIVES OVER MY
FAR SOUTHWEST ZONES TOWARDS DAYBREAK. THEREFORE...WILL INTRODUCE A
SLEET/FREEZING RAIN MIX AFTER 9Z IN THE FAR SOUTHEAST. THROUGH
DAYBREAK...EXPECT 1 TO 3 INCHES OF SNOW ALONG AND SOUTHWEST OF A
CHARLEVOIX TO GAYLORD TO HARRISVILLE LINE...WITH SNOW COMING DOWN
PRETTY HEAVILY AS MORNING ARRIVES IN THESE SPOTS. TEMPERATURES WILL
ONLY FALL OF A LITTLE OVERNIGHT...GENERALLY IN THE UPPER 20S TO
AROUND FREEZING.
TOUGH FORECAST FOR THE DAY WEDNESDAY AS LOW PRESSURE OCCLUDES AND
WARM NOSE CONTINUES TO SLOWLY MOVE NORTH. FIRST THINGS
FIRST...PRECIPITATION WILL CONTINUE TO PUSH NORTH AND SHOULD ARRIVE
OVER EASTERN UPPER NO LATER THAN LATE MORNING/NOON. FURTHER
SOUTH...BAND OF HEAVY SNOW WILL MAKE THE TRANSITION TO
SLEET/FREEZING RAIN AS TEMPS ALOFT WARM...BUT IT/S LOOKING LIKE A
PRETTY SMALL WINDOW FOR ICING POTENTIAL AS DEEP MOISTURE WILL
RAPIDLY LIFT OUT OF MY SOUTHERN ZONES BY MID MORNING /PERHAPS
QUICKER...HAVE SEEN THIS HAPPEN BEFORE/ TRANSITIONING PRECIPITATION
TO DRIZZLE/ AND SHOWERS. WITH THE SLIGHTLY FURTHER SOUTH
SOLUTION...EXPECT THAT ANY MIX WILL HAVE A TOUGH TIME REACHING MUCH
FARTHER NORTH THAN M-32 WITH PERHAPS SOME SLEET MIXING AT TIMES UP
TO M-68. BY AFTERNOON...EXPECT MOST LOCATIONS SOUTH OF M-68 TO
TRANSITION TO SOME DRIZZLE OR SHOWERS...WITH STRONG H7-5 LAPSE RATES
AND NON-NEGLIGIBLE ELEVATED INSTABILITY SUGGESTING ANY SHOWERS THAT
DEVELOP IN THE AIRMASS BEHIND THE SURFACE OCCLUSION COULD BE
ROBUST. SNOWFALL AMOUNTS WEDNESDAY LOOK GREATEST OVER EASTERN UPPER
WHERE 12 HOUR TOTALS NEAR 6 INCHES LOOK LIKELY GIVEN THAT THE
DRYSLOT WILL NEVER REACH THIS LOCATION. AMOUNTS WILL TAPER OFF
FURTHER SOUTH AND HAVE GONE A LITTLE BELOW THE GUIDANCE CONSENSUS
QPF GIVEN SYNOPTIC SETUP/PATTERN RECOGNITION. THIS WILL YIELD
ADDITIONAL SNOWS 1-2 INCHES NEAR M-72 UP TO 3-5 INCHES NEAR M-68.
SOUTH OF M-72 AND WEST OF US-131 THERE WILL LIKELY BE LITTLE/NO
ADDITIONAL SNOW...WITH ICING AMOUNTS GENERALLY ONE TENTH OF AN INCH
OR LESS.
FINALLY THERE IS ALSO GOING TO BE A WIND ELEMENT AS LOW PRESSURE
NEARS DURING THE DAY WEDNESDAY. THIS WILL LIKELY PRODUCE SOME
BLOWING/DRIFTING OF SNOW THAT FALLS...PARTICULARLY NEAR THE STRAITS
WHERE THE SNOW WILL BE /SLIGHTLY/ DRIER AND WINDS STRONGER. GUSTS
TO 35 MPH WILL BE POSSIBLE IN THIS REGION.
AS FOR HEADLINES...WILL ADD THE TIP OF THE MITT COUNTIES /EMMET
CHEBOYGAN/ AS WELL AS PRESQUE ISLE TO THE WARNING GIVEN 4-6 INCHES
OF SNOW AND LIKELY SIGNIFICANT BLOWING/DRIFTING NEAR THE COAST.
FURTHER SOUTH...IN COORDINATION WITH GRR/DTX WILL TRANSITION ALL
LOCATIONS TO A WINTER WEATHER ADVISORY FOR THE SNOW CHANGING TO
MIX.
ARNOTT
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 359 PM EST TUE FEB 28 2012
MAIN FOCUS OVER THE LONG TERM PORTION OF THE FORECAST WILL BE
HANDLING THE DEPARTURE OF WEDNESDAY`S SYSTEM AND WITH THE EVOLUTION
OF THE NEXT POTENTIALLY STRONG STORM SYSTEM FOR FRIDAY INTO THE
WEEKEND...AND THE LAKE EFFECT SNOW CHANCES THEREAFTER.
WEDNESDAY NIGHT...THE MESSY STORM SYSTEM WILL BE DEPARTING TO THE
EAST WITH A TRACK GENERALLY ACROSS M-68. THE OCCLUDED LOW PRESSURE
WILL CONTINUE TO WEAKEN ALONG WITH THE ASSOCIATED FORCING. THAT
SAID...WE ARE STILL GOING TO HAVE BROAD CYCLONIC FLOW/CONVERGENCE
FOR PRECIPITATION TO BE OCCURRING ALL OF NRN MICHIGAN FOR MOST OF
THE NIGHT...ESPECIALLY IN THE EVENING AND A FEW HOURS PAST
MIDNIGHT...AHEAD OF APPROACHING SFC/UPPER LOWS. TRYING TO PICK OUT
THE PARTICULAR PRECIPITATION TYPES IN THE EARLY EVENING IS A RATHER
DAUNTING TASK...AS INITIAL DRY SLOTTING ALOFT IS LIKELY TO RESULT IN
SOME DRIZZLE TYPE PRECIP FROM NRN LOWER AND THEN INTO EASTERN UPPER
DURING THE EVENING AND TO SOME DEGREE OVERNIGHT. IN ADDITION...AND
DEPENDING ON RATE OF DECAY OF THE TROWAL...COULD EVEN SEE SOME EARLY
EVENING SNOW/SLEET LINGERING OVER THE ALPENA AREA. THE DEEPEST
MOISTURE WILL PASS THROUGH NRN LOWER FOR OCCASIONAL LIGHT SNOWS
THROUGH MUCH OF THE NIGHT...WHILE SOME LIGHT SNOW AND OCCASIONAL
DRIZZLY TYPE PRECIP COULD BE ON AND OFF ACROSS EASTERN UPPER THROUGH
THE NIGHT. PRECIP WILL WIND DOWN ACROSS NW LOWER TOWARD DAYBREAK
WITH THE ATMOSPHERE DRYING OUT MORE SUBSTANTIALLY. TOTAL SNOWFALL
WILL GENERALLY BE AROUND AN INCH FOR MOST ALL OF NRN MICHIGAN...WITH
SOME 2 INCH REPORTS LIKELY.
THURSDAY THROUGH THURSDAY NIGHT...SOME ILL-DEFINED TROUGHING REMAINS
STRETCHED OUT ACROSS NE LOWER THROUGH EASTERN UPPER THROUGH THE DAY
WHILE MOISTURE CONTINUES TO EXIT EAST. ONLY SMALL CHANCES FOR
LINGERING LIGHT PRECIP (LIGHT SNOW/FREEZING DRIZZLE) EARLY IN THE
MORNING. THIS DAY WILL BE BETTER CHARACTERIZED BY RIDGING ALOFT AND
DRYING...WHILE NEXT UPPER TROUGH SHARPENS/DROPS THROUGH THE ROCKIES
WITH BROAD LOW PRESSURE IN THE CENTER OF THE COUNTRY. THROUGH
THURSDAY NIGHT...A COUPLE OF AREAS OF LOW PRESSURE ARE EXPECTED TO
BECOME MORE DEFINED. ONE WITH SHORTWAVE ACTIVITY IN SRN CANADA AND
OUR NRN BORDER...AND ANOTHER NEAR KS/OK ASSOCIATED WITH STRONGER
SHORTWAVE/STRENGTHENING UPPER JET DYNAMICS ROUNDING THE BASE OF THE
UPPER TROUGH. SKIES WILL BE INCREASING IN CLOUDINESS THROUGH THE
NIGHT WITHIN INITIAL WEAK PVA...WITH ONLY SMALL CHANCES OF BROAD
SCALE THETA-E ADVECTION MOISTENING UP THE ATMOSPHERE ENOUGH FOR SOME
LIGHT SNOW OR FLURRIES ACROSS NW LOWER THROUGH EASTERN UPPER.
FRIDAY ONWARD...DETAILS ARE STILL UNCLEAR ON WHAT HAPPENS FRIDAY
THROUGH SATURDAY...AS THERE ARE STILL CONSIDERABLE DIFFERENCES
REGARDING THE SFC AND UPPER LEVEL PATTERNS IN MODEL SOLUTIONS. THE
GENERAL IDEA IS FOR THE NRN/SRN STREAM WAVES TO UNDERGO SOME SORT OF
PHASING FRIDAY INTO SATURDAY...WITH ONE CONSOLIDATED SFC LOW
PRESSURE STRENGTHENING...OR POSSIBLY "BOMBING" OUT...DEEPENING
NEARLY 30 MB OVER 18 HRS. NOW...THE MAIN QUESTION IS WHERE AND WHEN
THIS WILL OCCUR...SINCE IT WILL HAVE OBVIOUS IMPLICATIONS ON THE
SPECIFIC WEATHER TO OCCUR. GEM THE OUTLIER AND HAS WEAKEST AND
FURTHEST EAST PHASING...WITH THE GFS THE MOST RADICAL IN
STRENGTHENING. EVEN WITH THINGS BEING UNCLEAR ON MANY PARTS...THERE
IS SOME DECENT AGREEMENT ON THE LOW PRESSURE GATHERING STRENGTH AS
IT PASSES OVER OR JUST TO OUR EAST THROUGH SATURDAY. HOW MUCH
MOISTURE IS INVOLVED...AND OTHER MORE DETAILED THINGS ARE DEFINITELY
MORE UNCLEAR...BUT A RAIN/SNOW SCENARIO IS THE BEST FORECAST AT THIS
POINT...WITH RAIN EAST AND SNOW IN THE NW CWA. CAN REFINE THE
DETAILS AS THINGS UNFOLD. ONE OTHER COMMONALITY WITH THESE SOLUTIONS
IS FOR COLD ENOUGH AIR TO DRAIN INTO NRN MICHIGAN WITH DEEP ENOUGH
MOISTURE FOR A PERIOD OF LAKE EFFECT SNOW PRIMARILY SATURDAY NIGHT
THROUGH SUNDAY NIGHT. MAYBE SOME DECENT ACCUMS IF THE SAME GENERAL
IDEAS ARE UPHELD IN FUTURE MODEL RUNS. THINGS QUIET DOWN FROM LES
LATE MONDAY/TUESDAY OR SO...WITH EVIDENCE OF STRONG WARMING ARRIVING
TUESDAY AND POSSIBLY WEDNESDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1208 AM EST WED FEB 28 2012
LOW PRESSURE OVER THE MIDWEST WILL ADVANCE INTO THE WESTERN GREAT
LAKES ON WEDNESDAY...AND THEN SLOWLY MOVE THROUGH LOWER MICHIGAN
WEDNESDAY NIGHT. AHEAD OF THE LOW...FIRST ROUND OF PRECIP STARTING
TO WORK INTO THE NRN LOWER MICHIGAN AND WILL OVERSPREAD THE
TERMINAL SITES...SOUTH THROUGH NORTH...THROUGHOUT THE OVERNIGHT
HOURS. AS THIS OCCURS...CONDITIONS WILL DETERIORATE TO IFR BY
MORNING (SEE TAFS FOR TIMING DETAILS).
ROUND OF FAIRLY HEAVY PRECIP (MAINLY SNOW) WILL IMPACT NRN LOWER
MICHIGAN WEDNESDAY MORNING BEFORE TAPERING OFF TO LIGHT SNOW/DRIZZLE
OR FREEZING DRIZZLE...SOUTH-NORTH DURING THE AFTERNOON...AS MID
LEVEL DRY SLOT ADVANCES UP THROUGH THE REGION. LOW CIGS/VSBYS WILL
REMAIN HOWEVER.
FINALLY...VERY STRONG LOW LEVEL FLOW WILL DEVELOP WEDNESDAY
MORNING LEADING TO LOW LEVEL WIND SHEAR CONDITIONS THROUGH MUCH OF
THE DAY.
&&
.MARINE...
ISSUED AT 359 PM EST TUE FEB 28 2012
WILL GO AHEAD AND EXPAND GALE WARNINGS TO BASICALLY INCLUDE ALL
ZONES SAVE STURGEON POINT TO ALABASTER AS BOUNDARY LAYER WINDS TO
40KTS /950MB TO 50KTS/ WITH SOME LLEVEL MIXING SUGGESTS THAT GUSTS
TO GALE FORCE ARE LIKELY JUST ABOUT EVERYWHERE...WITH THE
STRONGEST WINDS THROUGH THE STRAITS WHERE SOME FUNNELING/COASTAL
CONVERGENCE WILL GIVE THINGS AN ADDED BOOST. WINDS AND WAVES WILL
DIMINISH LATE WEDNESDAY NIGHT AND THURSDAY AS LOW PRESSURE PULLS
EAST OF THE REGION. ANOTHER ROUND OF STRONG WINDS LOOKS POSSIBLE
IN THE FRIDAY-SATURDAY TIMEFRAME AS A NEW LOW PRESSURE SYSTEM
DEVELOPS IN THE GREAT LAKES REGION. THERE/S PLENTY OF TIME TO LOOK
AT THIS SYSTEM...BUT AT THIS EARLY JUNCTURE GALES LOOK TO BE A
DISTINCT POSSIBILITY.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR
MIZ019>021-025>027-031>036-041-042.
WINTER STORM WARNING FROM 4 AM EARLY THIS MORNING TO 5 AM EST
THURSDAY FOR MIZ016>018-022>024-028>030.
WINTER STORM WARNING FROM 7 AM THIS MORNING TO 5 AM EST THURSDAY
FOR MIZ008-015.
LH...SMALL CRAFT ADVISORY UNTIL 11 PM EST THIS EVENING FOR LHZ349.
GALE WARNING UNTIL 11 PM EST THIS EVENING FOR LHZ345>348.
LM...GALE WARNING UNTIL 11 PM EST THIS EVENING FOR LMZ341-342.
GALE WARNING UNTIL 5 PM EST THIS AFTERNOON FOR LMZ323-344>346.
LS...NONE.
&&
$$
UPDATE...LAWRENCE
SHORT TERM...ARNOTT
LONG TERM....SMD
AVIATION...BA
MARINE...ARNOTT
AREA FORECAST DISCUSSION
NWS GAYLORD MI
1208 AM EST WED FEB 29 2012
.UPDATE...
ISSUED AT 1035 PM EST TUE FEB 28 2012
HAVE UPGRADED SOME COUNTIES IN NORTHERN LOWER MICHIGAN TO A
WARNING.
LOW PRESSURE NOW ADVANCING THROUGH EASTERN IOWA AHEAD OF A VERY
VIGOROUS UPPER LEVEL SHORT WAVE EJECTING NORTHEASTWARD FROM THE
CENTRAL PLAINS. VERY STRONG PULSE OF WARM ADVECTION FORCING/MOISTURE
FEED STARTING TO TAP THE GULF LEADING TO TO A LARGE EXPANDING
SHIELD OF PRECIP FROM ILLINOIS UP ACROSS WISCONSIN/MINNESOTA AND
THE DAKOTAS. STRONG CONVECTION BREAKING OUT IN THE CENTRAL PLAINS.
PRETTY MUCH YOUR TYPICAL STRONG SPRING STORM.
ACROSS THE REGION...A PRETTY HEFTY BATCH OF SNOWFALL HAS ALREADY
BLOSSOMED OVER SRN/ERN WISCONSIN THIS EVENING AND ABOUT TO WORK
INTO THE SW PART OF THIS CWA. BUT THE STRONGEST FORCING IS YET TO
ARRIVE...
OVERNIGHT...LOW PRESSURE SYSTEM WILL OCCLUDE OVER THE
IOWA/MINNESOTA REGION OVER THE NEXT SEVERAL HOURS. AS THIS
OCCURS...VERY STRONG PULSE OF WARM ADVECTION FORCING AND
ASSOCIATED WING OF PRECIP WILL ADVANCE UP THROUGH LOWER MICHIGAN
OVERNIGHT AND UP INTO EASTERN UPPER MICHIGAN WEDNESDAY
MORNING...FOLLOWED BY A SHARP DRY PUNCH OF AIR WORKING THROUGH THE
CWA DURING THE AFTERNOON. PRETTY MUCH IN LINE WITH PREVIOUS
FORECAST THINKING.
INITIALLY...WAS SKEPTICAL OF NAM/GFS QPF AMOUNTS APPROACHING ONE
INCH BY WEDNESDAY EVENING WITH THIS STORM...ESPECIALLY GIVEN THAT
BULK OF PRECIP WILL ONLY LAST AROUND 6 HOURS BEFORE TAPERING OFF
SHARPLY TO DRIZZLE/FREEZING DRIZZLE WITHIN THE DRY SLOT DURING THE
AFTERNOON HOURS. HOWEVER...MODEL N-S CROSS SECTIONS ACROSS LOWER
MICHIGAN HAVE CHANGED MY MIND. VERY IMPRESSIVE F-GEN DEVELOPS
ACROSS THE REGION WEDNESDAY MORNING WITHIN THE SHARPLY CYCLONIC
FLOW AND VERY STRONG WIND CORE THAT WORKS UP THROUGH THE REGION.
RESULTING OMEGA BULLSEYE IS IMPRESSIVE...MAXIMIZING IN THE DGZ
RIGHT UP ACROSS NRN LOWER MICHIGAN FOR A TIME WEDNESDAY MORNING.
TERRAIN AND A STRONG SE LOW LEVEL FLOW WILL LIKELY HELP THE CAUSE
OVER NE AND NORTH CENTRAL LOWER MICHIGAN AS WELL.
GIVEN THAT...AND A SLIGHTLY SLOWER TREND IN THE 00Z GUIDANCE SUGGESTING
MORE PRECIP OVER NRN LOWER MICHIGAN...HAVE EXPANDED WARNING DOWN
TWO TIER OF COUNTIES IN NRN LOWER MICHIGAN. HAVE TENTATIVELY LEFT
OUT CHARLEVOIX/ANTRIM COUNTIES AS DOWNSLOPING SE FLOW MAY KEEP PRECIP
IN CHECK...WILL SEE. STILL NOT CONVINCED WE SEE AN INCH OF LIQUID
WITH THIS SYSTEM. BUT EVEN IF WE GET CLOSE...ACCUMULATIONS IN THE
4 TO 7 INCH RANGE CERTAINLY VERY POSSIBLE OVER PORTIONS OF NE
LOWER MICHIGAN.
PRECIP TYPE ISSUES REMAIN WITH THIS SYSTEM...AS ABOVE FREEZING
WARM NOSE SURGES UP INTO NRN LOWER MICHIGAN ON WEDNESDAY.
BUT...TIMING IS EVERYTHING...AND BULK OF PRECIP ACROSS THE CWA
WILL BE LARGELY OVER BEFORE THE WARM NOSE ARRIVES. SO AT THIS
POINT...AM NOT TOO CONCERNED ABOUT SIGNIFICANT ICING OR PRECIP
CHANGING TO RAIN...AT LEAST DURING THE HEAVIEST PART OF THE EVENT.
UPDATE ISSUED AT 732 PM EST TUE FEB 28 2012
JUST MINOR TWEAKS TO THE FORECAST AT THIS POINT. HAVE RE-TOOLED
POPS/WEATHER FOR THIS EVENING THAT ADDRESSES THIS INITIAL CORRIDOR
OF LIGHT SNOW...WAY OUT AHEAD OF THE MAIN SHOW. INITIAL BATCH OF
LIGHT SNOW DRIVING ALONG BY ENTRANCE REGION UPPER JET FORCING AND
INITIAL PULSE OF WARM ADVECTION ALOFT...AND WON/T AMOUNT TO MUCH
THIS EVENING.
HOWEVER...BIGGER SURGE OF MID LEVEL WARM ADVECTION FORCING AND
ADVANCING MID LEVEL THETA-E GRADIENT ALREADY LEADING TO EXPANDING
AREA OF HEAVIER SNOWFALL ACROSS SRN WISCONSIN. THIS INITIAL BATCH
OF SNOWFALL WILL REACH THE SW PART OF THIS CWA BY LATE EVENING...
BUT MAY BE WEAKENING AS IT DOES SO. BOTTOM LINE...MAY HAVE TO
SPEED UP ARRIVAL OF CATEGORICAL SNOWFALL INTO THOSE SW COUNTIES IF
CURRENT TRENDS HOLD.
&&
.SYNOPSIS...
ISSUED AT 359 PM EST TUE FEB 28 2012
A LOW PRESSURE SYSTEM OVER THE CENTRAL PLAINS WILL CONTINUE TO
ADVANCE TOWARDS NORTHERN MICHIGAN...GENERATING A WINTRY MIX OF
PRECIPITATION WHICH WILL BEGIN LATE TONIGHT...AND LAST THROUGH
WEDNESDAY NIGHT...WITH HEAVY SNOW EXPECTED OVER THE UPPER
PENINSULA. AFTER A BRIEF BREAK THURSDAY AS AN AREA OF HIGH
PRESSURE BUILDS OVER THE REGION...ANOTHER LOW PRESSURE SYSTEM WILL
START TO TAKE SHAPE IN THE WESTERN GREAT LAKES ON FRIDAY.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 359 PM EST TUE FEB 28 2012
TOP DOWN SATURATION ONGOING OVER THE FORECAST AREA WITH SNOW ALREADY
HAVING REACHING THE GROUND FROM BEAVER ISLAND EAST TO MACKINAC
ISLAND. THIS SNOW HAS DEVELOPED LESS IN RESPONSE TO OUR UPCOMING
WEATHER-MAKER...AND MORE IN-LINE WITH THE RIGHT ENTRANCE REGION OF A
H25 JET MAX THAT EXTENDS FROM LAKE SUPERIOR SOUTH AND EAST INTO
SOUTHERN ONTARIO...AS WELL AS A WEAK PV ANOMALY SEEN IN WATER VAPOR
IMAGERY NOW JUST NORTH EAST OF LAKE SUPERIOR AND RACING EAST. THESE
FEATURES...COMBINED WITH STRENGTHENING UPSTREAM WARM ADVECTION IN
ADVANCE OF EJECTING FOUR CORNERS SHORTWAVE HAS HELPED CONSOLIDATE A
BAND OF MID LEVEL FRONTOGENESIS...WITH JUST ENOUGH MOISTURE FOR SNOW
TO REACH THE GROUND. ANYTHING THROUGH THIS EVENING SHOULD BE PRETTY
LIGHT...HOWEVER...AND AS THE AFOREMENTIONED SHORTWAVE PUSHES
EAST...WE WILL LIKELY SEE THIS ACTIVITY DRY UP SOME WITH PERHAPS
JUST A FEW FLURRIES OVER NORTHWEST LOWER AND THE STRAITS REGION WITH
STRENGTHENING DRY LOW LEVEL SOUTHEASTERLY FLOW HELPING ERODE ANY
MOISTURE. EARLY AFTERNOON HRRR IS IN GOOD AGREEMENT WITH THESE
TRENDS.
A WINTER WEATHER MESS IS SET TO ARRIVE LATE TONIGHT COURTESY OF THE
AFOREMENTIONED SHORTWAVE EJECTING OUT OF THE SOUTHWESTERN
STATES...BEING KICKED NORTH AND EAST BY ARRIVING ENERGY ALONG THE
PACIFIC COAST. MODEL INITIALIZATION WAS GENERALLY GOOD AT 12UTC
WITH ANY ERRORS NOT ENOUGH TO PRODUCE SIGNIFICANT DIFFERENCES IN
FORECASTS FROM THE NAM/GFS/ECMWF. THE TREND OVER THE PAST 24 HOURS
OF A MORE ROBUST AND NORTHERN SOLUTION TO THE SURFACE LOW HAS ENDED
WITH ALL GUIDANCE SHOWING A SLIGHT SOUTHWARD SHIFT IN THEIR 12Z
SOLUTIONS WITH GOOD CLUSTERING OF THE GEFS AROUND THE GFS AND THE
09Z SREF CLOSE TO THE 12Z NAM. THIS BRINGS LOW PRESSURE NORTHEAST
ACROSS THE CENTRAL PLAINS TO A POSITION OVER SOUTHWEST MINNESOTA BY
DAYBREAK WEDNESDAY /NEAR 990 MB/ WITH A LOW TRACK THAT THEN MOVES
JUST ABOUT DUE EAST AS THE SYSTEM OCCLUDES. IN TERMS OF PATTERN
RECOGNITION...H7 LOW TRACK MOVES EAST ACROSS NORTHERN LOWER SOMETIME
WEDNESDAY NIGHT...SUGGESTING THE BEST CHANCES FOR PROLONGED SNOWS
WILL BE FROM THE TIP OF THE MITT NORTH.
OUR WEATHER-MAKER WILL HAVE AMPLE MOISTURE TO WORK WITH AS THE GULF
WAS WIDE OPEN AS OF 12UTC WITH H85 DEWPOINTS AT OR ABOVE 10C
STREAMING NORTH ACROSS TX/OK/AK/LA. THE RESULT OF STRENGTHENING
MOISTURE ADVECTION WILL BE 1" PWATS MAKING A RUN AT THE SOUTHERN
GREAT LAKES TONIGHT.
TONIGHT...BAND OF STRONG ISENTROPIC ASCENT ON THE I290 SURFACE WILL
SPREAD NORTH AS THE AFOREMENTIONED STREAM OF MOISTURE PUSHES NORTH.
PRIMARY FORECAST CONCERN TONIGHT RESIDES AROUND PRECIPITATION START
TIME...AS DRY LOW LEVEL SOUTHEASTERLY FLOW ATTEMPTS TO ERODE
MOISTURE AS IT ARRIVES. THERE HAS BEEN A NOTICEABLE TREND TO SLOW
PRECIPITATION ONSET TIME WITH THE 12UTC GUIDANCE...WHICH IS VERY
REASONABLE GIVEN THE SETUP. HAVE ADJUSTED POPS FOR THIS
REASON...WHICH SHOULD KEEP PRECIPITATION SOUTH OF THE BRIDGE THROUGH
DAYBREAK. FURTHER SOUTH...A SWATH OF MODERATE TO POTENTIALLY HEAVY
PRECIPITATION WILL ARRIVE FROM SOUTHWEST TO NORTHEAST. WITHIN THIS
BAND...INGREDIENTS LOOK GOOD FOR SOME BANDED HEAVY SNOW POTENTIAL...
WITH OMEGA BULLS-EYED NEAR OR AT OR JUST ABOVE THE CENTER OF THE DGZ
WITH REDUCED EPV ALOFT AS STRONG WARM ADVECTION REDUCES MID LEVEL
LAPSE RATES. PRECIPITATION TYPE ISSUES WILL ENSUE QUICKLY BEHIND
INITIAL EDGE OF SNOWFALL AS WETBULB ZERO LINE AT H85 ARRIVES OVER MY
FAR SOUTHWEST ZONES TOWARDS DAYBREAK. THEREFORE...WILL INTRODUCE A
SLEET/FREEZING RAIN MIX AFTER 9Z IN THE FAR SOUTHEAST. THROUGH
DAYBREAK...EXPECT 1 TO 3 INCHES OF SNOW ALONG AND SOUTHWEST OF A
CHARLEVOIX TO GAYLORD TO HARRISVILLE LINE...WITH SNOW COMING DOWN
PRETTY HEAVILY AS MORNING ARRIVES IN THESE SPOTS. TEMPERATURES WILL
ONLY FALL OF A LITTLE OVERNIGHT...GENERALLY IN THE UPPER 20S TO
AROUND FREEZING.
TOUGH FORECAST FOR THE DAY WEDNESDAY AS LOW PRESSURE OCCLUDES AND
WARM NOSE CONTINUES TO SLOWLY MOVE NORTH. FIRST THINGS
FIRST...PRECIPITATION WILL CONTINUE TO PUSH NORTH AND SHOULD ARRIVE
OVER EASTERN UPPER NO LATER THAN LATE MORNING/NOON. FURTHER
SOUTH...BAND OF HEAVY SNOW WILL MAKE THE TRANSITION TO
SLEET/FREEZING RAIN AS TEMPS ALOFT WARM...BUT IT/S LOOKING LIKE A
PRETTY SMALL WINDOW FOR ICING POTENTIAL AS DEEP MOISTURE WILL
RAPIDLY LIFT OUT OF MY SOUTHERN ZONES BY MID MORNING /PERHAPS
QUICKER...HAVE SEEN THIS HAPPEN BEFORE/ TRANSITIONING PRECIPITATION
TO DRIZZLE/ AND SHOWERS. WITH THE SLIGHTLY FURTHER SOUTH
SOLUTION...EXPECT THAT ANY MIX WILL HAVE A TOUGH TIME REACHING MUCH
FARTHER NORTH THAN M-32 WITH PERHAPS SOME SLEET MIXING AT TIMES UP
TO M-68. BY AFTERNOON...EXPECT MOST LOCATIONS SOUTH OF M-68 TO
TRANSITION TO SOME DRIZZLE OR SHOWERS...WITH STRONG H7-5 LAPSE RATES
AND NON-NEGLIGIBLE ELEVATED INSTABILITY SUGGESTING ANY SHOWERS THAT
DEVELOP IN THE AIRMASS BEHIND THE SURFACE OCCLUSION COULD BE
ROBUST. SNOWFALL AMOUNTS WEDNESDAY LOOK GREATEST OVER EASTERN UPPER
WHERE 12 HOUR TOTALS NEAR 6 INCHES LOOK LIKELY GIVEN THAT THE
DRYSLOT WILL NEVER REACH THIS LOCATION. AMOUNTS WILL TAPER OFF
FURTHER SOUTH AND HAVE GONE A LITTLE BELOW THE GUIDANCE CONSENSUS
QPF GIVEN SYNOPTIC SETUP/PATTERN RECOGNITION. THIS WILL YIELD
ADDITIONAL SNOWS 1-2 INCHES NEAR M-72 UP TO 3-5 INCHES NEAR M-68.
SOUTH OF M-72 AND WEST OF US-131 THERE WILL LIKELY BE LITTLE/NO
ADDITIONAL SNOW...WITH ICING AMOUNTS GENERALLY ONE TENTH OF AN INCH
OR LESS.
FINALLY THERE IS ALSO GOING TO BE A WIND ELEMENT AS LOW PRESSURE
NEARS DURING THE DAY WEDNESDAY. THIS WILL LIKELY PRODUCE SOME
BLOWING/DRIFTING OF SNOW THAT FALLS...PARTICULARLY NEAR THE STRAITS
WHERE THE SNOW WILL BE /SLIGHTLY/ DRIER AND WINDS STRONGER. GUSTS
TO 35 MPH WILL BE POSSIBLE IN THIS REGION.
AS FOR HEADLINES...WILL ADD THE TIP OF THE MITT COUNTIES /EMMET
CHEBOYGAN/ AS WELL AS PRESQUE ISLE TO THE WARNING GIVEN 4-6 INCHES
OF SNOW AND LIKELY SIGNIFICANT BLOWING/DRIFTING NEAR THE COAST.
FURTHER SOUTH...IN COORDINATION WITH GRR/DTX WILL TRANSITION ALL
LOCATIONS TO A WINTER WEATHER ADVISORY FOR THE SNOW CHANGING TO
MIX.
ARNOTT
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 359 PM EST TUE FEB 28 2012
MAIN FOCUS OVER THE LONG TERM PORTION OF THE FORECAST WILL BE
HANDLING THE DEPARTURE OF WEDNESDAY`S SYSTEM AND WITH THE EVOLUTION
OF THE NEXT POTENTIALLY STRONG STORM SYSTEM FOR FRIDAY INTO THE
WEEKEND...AND THE LAKE EFFECT SNOW CHANCES THEREAFTER.
WEDNESDAY NIGHT...THE MESSY STORM SYSTEM WILL BE DEPARTING TO THE
EAST WITH A TRACK GENERALLY ACROSS M-68. THE OCCLUDED LOW PRESSURE
WILL CONTINUE TO WEAKEN ALONG WITH THE ASSOCIATED FORCING. THAT
SAID...WE ARE STILL GOING TO HAVE BROAD CYCLONIC FLOW/CONVERGENCE
FOR PRECIPITATION TO BE OCCURRING ALL OF NRN MICHIGAN FOR MOST OF
THE NIGHT...ESPECIALLY IN THE EVENING AND A FEW HOURS PAST
MIDNIGHT...AHEAD OF APPROACHING SFC/UPPER LOWS. TRYING TO PICK OUT
THE PARTICULAR PRECIPITATION TYPES IN THE EARLY EVENING IS A RATHER
DAUNTING TASK...AS INITIAL DRY SLOTTING ALOFT IS LIKELY TO RESULT IN
SOME DRIZZLE TYPE PRECIP FROM NRN LOWER AND THEN INTO EASTERN UPPER
DURING THE EVENING AND TO SOME DEGREE OVERNIGHT. IN ADDITION...AND
DEPENDING ON RATE OF DECAY OF THE TROWAL...COULD EVEN SEE SOME EARLY
EVENING SNOW/SLEET LINGERING OVER THE ALPENA AREA. THE DEEPEST
MOISTURE WILL PASS THROUGH NRN LOWER FOR OCCASIONAL LIGHT SNOWS
THROUGH MUCH OF THE NIGHT...WHILE SOME LIGHT SNOW AND OCCASIONAL
DRIZZLY TYPE PRECIP COULD BE ON AND OFF ACROSS EASTERN UPPER THROUGH
THE NIGHT. PRECIP WILL WIND DOWN ACROSS NW LOWER TOWARD DAYBREAK
WITH THE ATMOSPHERE DRYING OUT MORE SUBSTANTIALLY. TOTAL SNOWFALL
WILL GENERALLY BE AROUND AN INCH FOR MOST ALL OF NRN MICHIGAN...WITH
SOME 2 INCH REPORTS LIKELY.
THURSDAY THROUGH THURSDAY NIGHT...SOME ILL-DEFINED TROUGHING REMAINS
STRETCHED OUT ACROSS NE LOWER THROUGH EASTERN UPPER THROUGH THE DAY
WHILE MOISTURE CONTINUES TO EXIT EAST. ONLY SMALL CHANCES FOR
LINGERING LIGHT PRECIP (LIGHT SNOW/FREEZING DRIZZLE) EARLY IN THE
MORNING. THIS DAY WILL BE BETTER CHARACTERIZED BY RIDGING ALOFT AND
DRYING...WHILE NEXT UPPER TROUGH SHARPENS/DROPS THROUGH THE ROCKIES
WITH BROAD LOW PRESSURE IN THE CENTER OF THE COUNTRY. THROUGH
THURSDAY NIGHT...A COUPLE OF AREAS OF LOW PRESSURE ARE EXPECTED TO
BECOME MORE DEFINED. ONE WITH SHORTWAVE ACTIVITY IN SRN CANADA AND
OUR NRN BORDER...AND ANOTHER NEAR KS/OK ASSOCIATED WITH STRONGER
SHORTWAVE/STRENGTHENING UPPER JET DYNAMICS ROUNDING THE BASE OF THE
UPPER TROUGH. SKIES WILL BE INCREASING IN CLOUDINESS THROUGH THE
NIGHT WITHIN INITIAL WEAK PVA...WITH ONLY SMALL CHANCES OF BROAD
SCALE THETA-E ADVECTION MOISTENING UP THE ATMOSPHERE ENOUGH FOR SOME
LIGHT SNOW OR FLURRIES ACROSS NW LOWER THROUGH EASTERN UPPER.
FRIDAY ONWARD...DETAILS ARE STILL UNCLEAR ON WHAT HAPPENS FRIDAY
THROUGH SATURDAY...AS THERE ARE STILL CONSIDERABLE DIFFERENCES
REGARDING THE SFC AND UPPER LEVEL PATTERNS IN MODEL SOLUTIONS. THE
GENERAL IDEA IS FOR THE NRN/SRN STREAM WAVES TO UNDERGO SOME SORT OF
PHASING FRIDAY INTO SATURDAY...WITH ONE CONSOLIDATED SFC LOW
PRESSURE STRENGTHENING...OR POSSIBLY "BOMBING" OUT...DEEPENING
NEARLY 30 MB OVER 18 HRS. NOW...THE MAIN QUESTION IS WHERE AND WHEN
THIS WILL OCCUR...SINCE IT WILL HAVE OBVIOUS IMPLICATIONS ON THE
SPECIFIC WEATHER TO OCCUR. GEM THE OUTLIER AND HAS WEAKEST AND
FURTHEST EAST PHASING...WITH THE GFS THE MOST RADICAL IN
STRENGTHENING. EVEN WITH THINGS BEING UNCLEAR ON MANY PARTS...THERE
IS SOME DECENT AGREEMENT ON THE LOW PRESSURE GATHERING STRENGTH AS
IT PASSES OVER OR JUST TO OUR EAST THROUGH SATURDAY. HOW MUCH
MOISTURE IS INVOLVED...AND OTHER MORE DETAILED THINGS ARE DEFINITELY
MORE UNCLEAR...BUT A RAIN/SNOW SCENARIO IS THE BEST FORECAST AT THIS
POINT...WITH RAIN EAST AND SNOW IN THE NW CWA. CAN REFINE THE
DETAILS AS THINGS UNFOLD. ONE OTHER COMMONALITY WITH THESE SOLUTIONS
IS FOR COLD ENOUGH AIR TO DRAIN INTO NRN MICHIGAN WITH DEEP ENOUGH
MOISTURE FOR A PERIOD OF LAKE EFFECT SNOW PRIMARILY SATURDAY NIGHT
THROUGH SUNDAY NIGHT. MAYBE SOME DECENT ACCUMS IF THE SAME GENERAL
IDEAS ARE UPHELD IN FUTURE MODEL RUNS. THINGS QUIET DOWN FROM LES
LATE MONDAY/TUESDAY OR SO...WITH EVIDENCE OF STRONG WARMING ARRIVING
TUESDAY AND POSSIBLY WEDNESDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1208 AM EST WED FEB 28 2012
LOW PRESSURE OVER THE MIDWEST WILL ADVANCE INTO THE WESTERN GREAT
LAKES ON WEDNESDAY...AND THEN SLOWLY MOVE THROUGH LOWER MICHIGAN
WEDNESDAY NIGHT. AHEAD OF THE LOW...FIRST ROUND OF PRECIP STARTING
TO WORK INTO THE NRN LOWER MICHIGAN AND WILL OVERSPREAD THE
TERMINAL SITES...SOUTH THROUGH NORTH...THROUGHOUT THE OVERNIGHT
HOURS. AS THIS OCCURS...CONDITIONS WILL DETERIORATE TO IFR BY
MORNING (SEE TAFS FOR TIMING DETAILS).
ROUND OF FAIRLY HEAVY PRECIP (MAINLY SNOW) WILL IMPACT NRN LOWER
MICHIGAN WEDNESDAY MORNING BEFORE TAPERING OFF TO LIGHT SNOW/DRIZZLE
OR FREEZING DRIZZLE...SOUTH-NORTH DURING THE AFTERNOON...AS MID
LEVEL DRY SLOT ADVANCES UP THROUGH THE REGION. LOW CIGS/VSBYS WILL
REMAIN HOWEVER.
FINALLY...VERY STRONG LOW LEVEL FLOW WILL DEVELOP WEDNESDAY
MORNING LEADING TO LOW LEVEL WIND SHEAR CONDITIONS THROUGH MUCH OF
THE DAY.
&&
.MARINE...
ISSUED AT 359 PM EST TUE FEB 28 2012
WILL GO AHEAD AND EXPAND GALE WARNINGS TO BASICALLY INCLUDE ALL
ZONES SAVE STURGEON POINT TO ALABASTER AS BOUNDARY LAYER WINDS TO
40KTS /950MB TO 50KTS/ WITH SOME LLEVEL MIXING SUGGESTS THAT GUSTS
TO GALE FORCE ARE LIKELY JUST ABOUT EVERYWHERE...WITH THE
STRONGEST WINDS THROUGH THE STRAITS WHERE SOME FUNNELING/COASTAL
CONVERGENCE WILL GIVE THINGS AN ADDED BOOST. WINDS AND WAVES WILL
DIMINISH LATE WEDNESDAY NIGHT AND THURSDAY AS LOW PRESSURE PULLS
EAST OF THE REGION. ANOTHER ROUND OF STRONG WINDS LOOKS POSSIBLE
IN THE FRIDAY-SATURDAY TIMEFRAME AS A NEW LOW PRESSURE SYSTEM
DEVELOPS IN THE GREAT LAKES REGION. THERE/S PLENTY OF TIME TO LOOK
AT THIS SYSTEM...BUT AT THIS EARLY JUNCTURE GALES LOOK TO BE A
DISTINCT POSSIBILITY.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL 3 PM EST WEDNESDAY FOR MIZ019>021-
025>027-031>036-041-042.
WINTER STORM WARNING FROM 4 AM WEDNESDAY TO 5 AM EST THURSDAY
FOR MIZ016>018-022>024-028>030.
WINTER STORM WARNING FROM 7 AM WEDNESDAY TO 5 AM EST THURSDAY
FOR MIZ008-015.
LH...SMALL CRAFT ADVISORY UNTIL 11 PM EST WEDNESDAY FOR LHZ349.
GALE WARNING UNTIL 11 PM EST WEDNESDAY FOR LHZ345>348.
LM...GALE WARNING UNTIL 11 PM EST WEDNESDAY FOR LMZ341-342.
GALE WARNING UNTIL 5 PM EST WEDNESDAY FOR LMZ323-344>346.
LS...NONE.
&&
$$
UPDATE...BA
SHORT TERM...ARNOTT
LONG TERM....SMD
AVIATION...BA
MARINE...ARNOTT
AREA FORECAST DISCUSSION...UPDATED FOR 06Z TAFS
NWS TWIN CITIES/CHANHASSEN MN
1100 PM CST TUE FEB 28 2012
.DISCUSSION...ISSUED 300 PM CST
WHAT A DIFFERENCE ABOUT 125 MILES MAKES... WHICH IS ROUGHLY THE
DIFFERENCE IN WHERE THIS SYSTEM LOOKS TO BE TRACKING VS HOW IT
APPEARED TWO DAYS AGO. OVERALL... THIS MEANS THE FORECAST IS
PRETTY SIMILAR TO WHAT HAS BEEN EXPECTED... EXCEPT EVERYTHING HAS
BEEN SHIFTED BY ABOUT THAT DISTANCE NORTHWARD. THERE WILL BE SOME
ADDITIONAL CHANGES FORTHCOMING IN TERMS OF THE HEADLINES AND
SNOWFALL EXPECTATIONS... AS WELL AS THE NORTHWARD EXTENT OF MIXED
PRECIPITATION. LATEST WATER VAPOR IMAGERY AND RUC UPPER AIR
ANALYSES SHOW OUR SYSTEM FINALLY BEGINNING TO EMERGE FROM THE
SOUTHERN ROCKIES... WITH THE SURFACE LOW LOCATED NEAR THE
INTERSECTION OF COLORADO... NEBRASKA... AND KANSAS. THE GUIDANCE
IS... FINALLY... IN EXCELLENT AGREEMENT ON THE TIMING AND MOVEMENT
OF THIS SYSTEM... TAKING THE SURFACE LOW NORTHEAST INTO SOUTHERN
MINNESOTA BY 12Z WEDNESDAY... THEN VERY NEAR THE TWIN CITIES BY
18Z... BEFORE MOVING OFF TO THE GREAT LAKES WEDNESDAY NIGHT. SOME
DIFFERENCES DO REMAIN IN THE GUIDANCE IN TERMS OF EXACTLY HOW WARM
THE ELEVATED WARM LAYER WILL GET... AS WELL AS THE NEAR SURFACE
TEMPERATURES AND NORTHWARD EXTENT OF THE WARMER TEMPERATURES.
OVERALL... IT NOW LOOKS LIKE WE SHOULD GET SOME DEGREE OF MIXED
PRECIPITATION OVER ALL BUT PERHAPS THE FAR NORTHERN PART OF THE
AREA FOR A TIME TONIGHT. THE SOUTHERN CWFA HAS ALREADY
TRANSITIONED TO SLEET OR RAIN... AND THIS WILL CONTINUE TO PUSH
NORTH THROUGH THE EVENING. BASED THE FORECAST DETAILS ON A BLEND
OF GFS... NAM... AND SREF GUIDANCE... BUT WITH A BIT OF WEIGHT ON
THE RUC DURING THE FIRST 12 HOURS. ALSO LIKE THE GENERAL LOOK OF
THE HRRR PRECIPITATION/REFLECTIVITY FIELDS THROUGH THIS EVENING...
SO TOOK THAT INTO ACCOUNT.
AS MENTIONED... EXPECT TO SEE THE MIXED PRECIPITATION PUSH NORTH
THROUGH THIS EVENING AS THE STRONG LOW LEVEL JET PERSIST AHEAD OF
THE SURFACE LOW. SUFFICIENTLY WARM TEMPERATURES AROUND 850-825MB
LOOK TO GET AS FAR NORTH AS KAXN... BRINGING SOME CHANCE OF AT
LEAST ICE PELLETS INTO THE FAR NORTHERN PART OF THE FORECAST AREA.
A BRIEF WINDOW OF FREEZING RAIN STILL SEEMS POSSIBLE DURING THE
TRANSITION FROM SLEET TO RAIN WHICH WILL OCCUR OVER THE CENTRAL
AND SOUTHERN PART OF THE CWFA... ALTHOUGH OBSERVATIONS AND
FORECAST PROFILES SUGGEST THAT ANY FZRA SHOULD BE SHORT-LIVED WITH
THINGS PRIMARILY GOING FROM SLEET TO RAIN OVER NEARLY THE SOUTHERN
HALF OF THE AREA BY EARLY THIS EVENING. AS THE SYSTEM OCCLUDES
LATER TONIGHT AND WEDNESDAY MORNING AND BEGINS DRIFTING EAST WE
SHOULD SEE THINGS COOL DOWN ONCE AGAIN... WITH THE WARM TONGUE
ERODING FROM 09Z-15Z... CHANGING THE PCPN ASSOCIATED THE UPPER
TROUGH BACK TO SNOW FOR THE DAY ON WEDNESDAY. PRIOR TO THEN... IT
STILL APPEARS THAT WE WILL HAVE HEAVY PCPN TONIGHT... FALLING AS
SNOW AND SLEET OVER THE NORTH... SLEET AND RAIN OVER THE
CENTRAL... AND RAIN OVER THE SOUTH. HOWEVER... THE SOUTHERN PART
OF THE AREA SHOULD ALSO SEE THE DRY SLOT WORK IN... WHICH WILL END
HEAVIER PCPN IN THAT AREA TONIGHT. THERE IS SOME POSSIBILITY FOR
SOME CONVECTION TO DEVELOP IN THE DRY WEDGE... MAINLY TO OUR
SOUTH... BUT SOME ISOLATED THUNDER COULD GET UP INTO THE SOUTHERN
PART OF THE CWFA THIS EVENING INTO THE OVERNIGHT HOURS. IN THE
NORTH... WHERE THE PERSISTENT MODERATE TO HEAVY PCPN IS EXPECTED
TO OCCUR... SIGNIFICANT SNOWFALL ACCUMULATIONS STILL APPEAR
LIKELY... ALTHOUGH THEY MAY BE TEMPERED TO SOME DEGREE BY MIXING
WITH SLEET. STRONG MID-LEVEL FRONTOGENESIS... AND COUPLING WITH
THE UPPER JET CIRCULATION... STILL APPEAR TO BE IN PLACE FOR A
TIME TONIGHT... ALONG WITH NEGATIVE EPV NEAR AND ABOVE THAT LAYER
OF FORCING. OVER THE SOUTHERN PART OF THE AREA... THAT INSTABILITY
IS UPRIGHT GIVEN NEGATIVE DIFFERENTIAL THETA-E WHICH WILL BE IN
PLACE... BUT AS YOU GO NORTH THINGS SUGGEST IT WOULD BE MORE
SYMMETRIC IN NATURE. THAT WOULD SUGGEST MORE OF A CELLULAR PCPN
LOOK ON THE SOUTH END OF THINGS AS THEY PUSH NORTH LATER
TONIGHT... WITH MORE IN THE WAY OF BANDING FARTHER NORTH.
PCPN WILL LINGER THROUGH MUCH OF THE DAY ON WEDNESDAY AS THE UPPER
TROUGH SLOWLY PUSHES ACROSS THE AREA AND ABUNDANT DEEP LAYER
MOISTURE PERSISTS. SOME MIXED PCPN MAY STILL BE POSSIBLE IN THE
MORNING OVER THE SOUTHEAST PORTION OF THE AREA... BUT BY LATE
MORNING ANY REMAINING PCPN SHOULD BE IN THE FORM OF SNOW... WITH
SOME ADDITIONAL ACCUMULATIONS STILL EXPECTED... PARTICULARLY OVER
THE NORTH CENTRAL AND NORTHEAST CWFA. VERY WEAK RIDGING LOOKS TO
WORK INTO THE AREA WEDNESDAY NIGHT... BRINGING AN END THE PCPN...
BUT A WEAK NORTHERN STREAM SHORTWAVE MAY BRING A CHANCE OF SNOW
BACK INTO THE NORTHERN CWFA ON THURSDAY. THE NEXT FEATURE OF ANY
CONCERN STILL LOOKS LIKE IT WILL BE MOVING NEAR THE AREA ON
FRIDAY... BUT THE LATEST GUIDANCE CONTINUES THE IDEA OF KEEPING
THAT SYSTEM OFF TO OUR SOUTHEAST. WITH THE AFOREMENTIONED NORTHERN
STREAM UPPER TROUGH STILL IN THE VICINITY THROUGH FRIDAY... AND
THE SOUTHERN WAVE PASSING BY TO OUR SOUTHEAST... DID CARRY SOME
LOW POPS OVER MUCH OF THE AREA ON FRIDAY... BUT AT THIS POINT IT
DOES NOT APPEAR IT WILL BE MUCH OF AN ISSUE FOR OUR AREA. THE
WEEKEND INTO EARLY NEXT WEEK LOOK TO BE MAINLY DRY... ALTHOUGH
THERE COULD BE SOME FLURRIES AROUND OVER THE WEEKEND WITH CYCLONIC
FLOW AND FAIRLY STEEP BOUNDARY LAYER LAPSE RATES IN PLACE. DIDN/T
INCLUDE MUCH IN THE WAY OF PCPN MENTION AT THIS POINT... BUT
WOULDN/T BE SURPRISED TO EVENTUALLY NEED TO INCLUDE SOME SNOW
SHOWERS AND/OR FLURRIES FOR SATURDAY INTO SUNDAY. THE START OF
NEXT WEEK SHOULD SEE A SIGNIFICANT WARM UP ACROSS THE AREA AS
HEIGHTS BUILD... AND 1000-500MB THICKNESS VALUES CLIMB WELL ABOVE
555DM. INCLUDED HIGHS OF NEAR 50 DEGREES BY TUESDAY... WHICH
CERTAINLY DOESN/T LOOK UNREASONABLE AT THIS POINT SHOULD THINGS
WARM AS SUGGESTED.
&&
.AVIATION.../06Z TAF ISSUANCE/
00Z RUNS OF GFS/NAM NOW TAKE SFC LOW SLIGHTLY FARTHER SOUTH NEXT 24
HOURS...TRACKING JUST SOUTH OF MSP TO S OF EAU. FIRST WAVE OF PCPN
NOW COVERS ABOUT NE 1/2 OF CWA...WITH SOME SNOW TOTALS IN THE 2-4
INCH RANGE SO FAR ACROSS PARTS OF CNTL MN INTO WC WI. SFC TEMPS HAVE
BEEN STUBBORN TO RISE...HOLDING 31 TO 34 RANGE AT SITES WITH MIXED
PCPN MSP/RWF/EAU. PCPN HAS REMAINED ALL SNOW AT AXN/STC.
NEXT WAVE OF PCPN WITH SOME THUNDER IS ADVANCING INTO SW MN AHEAD OF
STRENGTHENING UPPER LOW. WILL HAVE A PERIOD OF THUNDER FOR RWF TIL
09Z. WV IMAGERY SHOWING COOLING CLOUD TOPS COOLING ACROSS SODAK/E
NEB/IA/SW MN AHEAD OF UPPER LOW. NAM IS A BIT MORE AGGRESSIVE ON
COOLING LOWER ATMOS COLUMN OVERNIGHT THAN GFS. METARS TEND TO
SUPPORT COOLER NAM WITH PCPN TRENDING TOWARD MORE SNOW.
STRONG ISENTROPIC LIFT AND PERSISTENT UVV ACROSS CENTRAL MN INTO WC
OVERNIGHT INTO WED MRNG SHUD YIELD PERIODS OF +SN AFFECING MAINLY
STC/AXN. SPED UP THE TRANSISTION TO SNOW A BIT ACROSS REMAINING
TAFS.
MSP...FIRST WAVE OF MIXED PCPN PULLING NE OF MSP WITH NEXT WAVE
RAPIDLY MOVING NE ACROSS SW MN...ARRIVING IN MSP BY 07Z. SFC TEMPS
WILL REMAIN JUST ABOVE FREEZING. METARS HAVE BEEN REPORTING -SN AS
CLOSE AS MIC/GYL. WITH LIFT FROM APPROACHING UPPER LOW SHOULD
CHANGE TO A MIX OF SNPL AROUND 09Z AND ALL SNOW BY 12Z. KEPT THUNDER
CHANCE S OF MSP..BUT COULD BE CLOSE BETWEEN 08Z AND 11Z. EXPECT SNOW
TOTALS AT MSP INTO MID DAY WEDNESDAY AROUND 3 INCHES. SFC WINDS WILL
BE A BIT STRONGER THAN PREVIOUS TAF WITH SFC LOW TRACKING S OF MSP.
.WED NIGHT...IFR/MVFR CIGS.
.THU/FRI. MVFR CIGS/VSBYS IN -SN. ..JLT..
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER WEATHER ADVISORY UNTIL 6 PM CST WEDNESDAY FOR BROWN-
CARVER-DAKOTA-GOODHUE-HENNEPIN-LE SUEUR-MCLEOD-NICOLLET-
RAMSEY-REDWOOD-RENVILLE-RICE-SCOTT-SIBLEY-WASHINGTON-YELLOW
MEDICINE.
WINTER STORM WARNING UNTIL 6 PM CST WEDNESDAY FOR ANOKA-BENTON-
CHIPPEWA-DOUGLAS-KANDIYOHI-LAC QUI PARLE-MEEKER-MORRISON-
POPE-SHERBURNE-STEARNS-STEVENS-SWIFT-TODD-WRIGHT.
WINTER STORM WARNING UNTIL 6 PM CST WEDNESDAY FOR CHISAGO-ISANTI-
KANABEC-MILLE LACS.
WI...WINTER WEATHER ADVISORY UNTIL 6 PM CST WEDNESDAY FOR DUNN-EAU
CLAIRE-PEPIN-PIERCE-ST. CROIX.
WINTER STORM WARNING UNTIL 6 PM CST WEDNESDAY FOR CHIPPEWA.
WINTER STORM WARNING UNTIL 6 PM CST WEDNESDAY FOR BARRON-POLK-
RUSK.
&&
$$
CLF/BAP
AREA FORECAST DISCUSSION
NWS SPRINGFIELD MO
220 AM CST WED FEB 29 2012
...MESOSCALE CONVECTIVE DISCUSSION...
.DISCUSSION...
/ISSUED 0215 AM CST WED FEB 29 2012/
A DANGEROUS LINE OF STORMS CONTINUES TO RACE ACROSS SOUTH CENTRAL
MISSOURI AND WILL CONTINUE ACROSS SOUTHERN MISSOURI THROUGH 5 AM.
NUMEROUS REPORTS OF WIND GUSTS IN EXCESS OF 70 MPH...HAIL TO THE
SIZE OF GOLF BALLS AND TORNADOES HAVE BEEN RECEIVED. THE THREAT
FOR SIGNIFICANT SEVERE WEATHER WILL CONTINUE THROUGH THE EASTERN
PORTION OF THE OUTLOOK AREA THROUGH 5 AM.
DIVING INTO VARIOUS MESOSCALE PARAMETERS...SIGNIFICANT O-1KM AND
0-3KM STORM RELATIVE HELICITY VALUES OF OVER 800 M2/S2 ARE
AVAILABLE ALONG AND AHEAD OF THE LINE OF CONVECTION. RUC BUFKIT
SOUNDINGS AHEAD OF THE LINE CONTINUE TO INDICATE STRONG 925MB
WINDS OF NEAR 50 KTS AND 850MB WINDS OF 60 TO 65KTS...WITH THIS
CONTINUING TO SUPPORT OUR STRONG SRH VALUES. SPC MESOANALYSIS PAGE
CONTINUES TO SHOW MLCAPE VALUES OVER 1000 J/KG ACROSS THE REGION.
RUC FORECASTS OF 0-1KM COMPUTED CAPE SHOW VALUES BETWEEN 300 AND
500 J/KG JUST AHEAD OF THE CONVECTIVE LINE...WITH NEAR 1000 J/KG
NOSING INTO THE EASTERN OZARKS. THESE PARAMETERS CONTINUE TO
SUPPORT OUR ELEVATED TORNADO RISK WITH BOWING SEGMENTS MOVING EAST
NORTHEAST ACROSS SOUTH CENTRAL MISSOURI.
WINDS IN EXCESS OF 70 MPH...TORNADOES AND LARGE HAIL WILL REMAIN
AN ELEVATED TO SIGNIFICANT RISK FOR THE REST OF TONIGHT WITH THIS
LINE OF STORMS. THIS IS A DANGEROUS SITUATION.
KURTZ
&&
.AVIATION...
FOR THE 06Z TAF PACKAGE...PRIMARY CONCERN WILL BE THE LINE OF
THUNDERSTORMS MOVING ACROSS THE REGION...EXPECT GUSTS AT BBG TO
PEAK NEAR 50KT OUT OF THE WEST. ONCE THIS LINE CLEARS TO THE
EAST...VFR CONDITIONS ARE EXPECTED...THOUGH GUSTY WEST WINDS WILL
CONTINUE THROUGH THE DAY.
GAGAN
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS SPRINGFIELD MO
1258 AM CST WED FEB 29 2012
...MESOSCALE CONVECTIVE DISCUSSION...
.DISCUSSION...
/ISSUED 1258 AM CST WED FEB 29 2012/
DANGEROUS LINE OF STORMS WILL RACE THROUGH THE AREA THROUGH 5 AM.
NUMEROUS REPORTS OF WIND GUSTS IN EXCESS OF 70 MPH...HAIL TO THE
SIZE OF GOLF BALLS AND TORNADOES HAVE BEEN RECEIVED. THE THREAT
FOR SIGNIFICANT SEVERE WILL CONTINUE THROUGH THE ENTIRE OUTLOOK
AREA WITH THIS LINE OF THUNDERSTORMS.
REFERENCING SPC/S MESOANALYST PAGE...MLCAPE IS NEAR 1000 J/KG WITH
0-1KM AND 0-3KM STORM RELATIVE HELICITY NEAR 750 M2/S2. GIVEN
925MB WINDS OF 50KT AND 850MB WINDS OF 70KT (AS MEASURED BY THE
04Z SPECIAL KSGF SOUNDING)...THE SRH VALUES PRODUCED ARE LIKELY
REPRESENTATIVE. RUC REPRESENTATION OF LOW LEVEL CAPE ESTIMATES
VALUES ARE 100 J/KG. THIS COMBINED WITH THE HIGH SRH VALUES IN THE
LOW LEVELS WILL MAINTAIN AN ELEVATED TORNADO RISK WITH THE BOW
ECHO SIGNATURE THAT IS MOVING EAST NORTHEAST THROUGH CENTRAL
MISSOURI AS WELL AS ANY OTHER LINE SEGMENTS THAT BECOME FAVORABLY
ORIENTED WITH THE WEST/SOUTHWEST 0-3KM SHEAR VECTORS.
WINDS IN EXCESS OF 70 MPH...TORNADOES AND LARGE HAIL WILL REMAIN
AN ELEVATED TO SIGNIFICANT RISK FOR THE REST OF TONIGHT WITH THIS
LINE OF STORMS. THIS IS A DANGEROUS SITUATION.
GAGAN
&&
.AVIATION...
FOR THE 06Z TAF PACKAGE...PRIMARY CONCERN WILL BE THE LINE OF
THUNDERSTORMS MOVING ACROSS THE REGION...EXPECT GUSTS AT BBG TO
PEAK NEAR 50KT OUT OF THE WEST. ONCE THIS LINE CLEARS TO THE
EAST...VFR CONDITIONS ARE EXPECTED...THOUGH GUSTY WEST WINDS WILL
CONTINUE THROUGH THE DAY.
GAGAN
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BUFFALO NY
347 AM EST WED FEB 29 2012
.SYNOPSIS...
HIGH PRESSURE OVER THE EASTERN GREAT LAKES AND NEW YORK STATE WILL
SLIDE TO THE EAST AS LOW PRESSURE OVER THE MIDWEST MOVES EASTWARD.
THERE WILL BE A MIX OF RAIN...SLEET AND SNOW ACROSS PARTS OF WESTERN
AND CENTRAL NEW YORK ON WEDNESDAY MORNING...THEN MAINLY RAIN AND
SNOW FOR THE AFTERNOON. RAIN WILL CHANGE BACK TO SNOW AND TAPER OFF
WEDNESDAY NIGHT.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE OVERNIGHT PERIOD WILL BE CLOUDY AND MAINLY DRY. WHILE
COMPOSITE RADAR APPEARS FAIRLY OMINOUS...THE 00Z BUFFALO SOUNDING
SHOWS QUITE DRY AIR BELOW 700 MB. THUS THE MAJORITY OF THE
COMPOSITE RADAR IS ACTUALLY VIRGA. THIS SAID...REFLECTIVITY OF 25
DBZ OR SO SUGGESTS SOME FLURRIES ARE LIKELY REACHING THE GROUND
IN SOME SPOTS. THIS BAND OF MID-UPPER LEVEL WARM AIR ADVECTION
WILL CONTINUE TO LIFT OFF TO THE NORTH...PERHAPS BRINGING A FLURRY
TO BUFFALO AND FAR WESTERN NEW YORK. HOWEVER...THIS SHOULD LIFT TO
THE NORTH SHORTLY AFTER MIDNIGHT...WHILE THE MAIN AREA OF
PRECIPITATION SHOULD NOT ENTER THE REGION UNTIL DAYBREAK. THE 18Z
GFS/12Z RGEM/00Z HRRR ALL BRING IN STEADY PRECIPITATION INTO FAR
WESTERN PORTIONS OF NEW YORK JUST SHY OF 12Z (700 AM). WITH CLOUDS
IN PLACE ACROSS MOST OF THE REGION... TEMPERATURES SHOULD DROP
VERY LITTLE OVERNIGHT.
A WARM FRONT BETWEEN THE DEPARTING HIGH AND APPROACHING LOW WILL
BRING ABOUT A MIX OF WINTRY PRECIP TO PARTS OF WESTERN AND CENTRAL
NY. THIS WILL BRING A BAND OF WARM AIR ADVECTION IN THE LOWER TO
MID LEVELS...WHICH WILL LIFT FROM SOUTHWEST TO NORTHEAST ACROSS THE
REGION ON WEDNESDAY. THERE SHOULD BE A RATHER QUICK CHANGEOVER TO
RAIN IN FAR SOUTHERN SECTIONS...WHERE WINDS SHIFTING TO THE
SOUTHEAST WILL BRING IN WARM AIR ALOFT. FURTHER TO THE NORTH AND
EAST WILL BE FURTHER FROM THE SURFACE LOW AND CLOSER TO COLD HIGH
PRESSURE ANCHORED IN QUEBEC. THIS WILL ALLOW SNOW TO LAST
LONGER INTO WEDNESDAY...WITH LOCATIONS EAST OF LAKE ONTARIO LIKELY
TO STAY SNOW THROUGH SUNSET.
NO CHANGES TO HEADLINES WERE MADE FOR THE EVENING UPDATE. HAVE
SOME CONCERN THAT TEMPERATURES WEDNESDAY MORNING WILL BE SLOW TO
RISE...GIVEN THE INVERSION FORECAST TO DEVELOP BENEATH THE MODEST
SW FLOW ALOFT. THUS DID BUMP DOWN TEMPERATURES A FEW DEGREES ON
WEDNESDAY MORNING. ALSO NUDGED UP SNOW ACCUMULATIONS EAST OF
ROCHESTER. THE 18Z NAM CONTINUES TO BE COLDER THAN THE 18Z GFS AND
MOST OF THE 12Z MODELS...WITH THE SREF TENDING TO SUPPORT THE
WARMER MODEL CAMP AS WELL. A BLEND PROVIDES SIMILAR CHANGEOVER
TIMES TO GOING FORECAST...BUT PERHAPS A TAD MORE QPF BASED ON
LATEST CONSENSUS. EXPECT BETWEEN .25 AND .50 FROM THE BROAD BAND
OF WARM AIR ADVECTION. THIS SHOULD BRING LIGHT ACCUMULATIONS...GENERALLY
2 INCHES OR LESS...WEST OF ROCHESTER...WITH POTENTIAL FOR 2 TO 4
INCHES EAST OF ROCHESTER TO OSWEGO COUNTY THROUGH WEDNESDAY
EVENING.
THE GREATEST POTENTIAL FOR ANY ICE CONTINUES TO BE ACROSS THE
SOUTHERN TIER. WARM AIR ALOFT WILL CROSS QUITE EARLY WEDNESDAY
MORNING...HOWEVER BELOW FREEZING SURFACE TEMPERATURES WILL LIKELY
LINGER WELL INTO THE MORNING. WITH DEW POINTS IN THE UPPER TEENS
AND LOWER 20S...EXPECT SURFACE TEMPERATURES TO DROP EARLY
WEDNESDAY MORNING DUE TO EVAPORATIONAL COOLING. THE ADVISORY
APPEARS TO BE WELL PLACED FOR THIS...WITH A LIGHT GLAZE OF A TENTH
OF AN INCH OR SO OF ICE LIKELY IN THE ADVISORY AREA. IF SURFACE
TEMPERATURES DO LINGER BELOW FREEZING LONGER...IT IS POSSIBLE
ICING TO A QUARTER INCH COULD OCCUR.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
THE WEAKENING/FILLING SURFACE WAVE WILL BE IN THE PROCESS OF
CROSSING THE REGION AT THE START OF THE PERIOD. THIS SYSTEM WILL
CONTINUE THE WIDESPREAD PRECIPITATION. COLDER AIR WILL ARRIVE BEHIND
THE LOW AS THE ASSOCIATED UPPER LOW CROSSES THE REGION ENHANCING
DYNAMIC COOLING. THIS PROCESS WILL ALLOW A CHANGE OVER TO A
RAIN/SNOW MIX WITH NEARLY ALL SNOW OVER HIGHER ELEVATIONS OF THE
SOUTHERN TIER AND ACROSS THE NORTH COUNTY. LITTLE ACCUMULATION
EXPECTED ACROSS THE SOUTHERN TIER...BUT COULD SEE ADDITIONAL
SNOWFALL AMOUNTS OF 2 INCHES ACROSS THE NORTH COUNTRY...IN AREA OF
DEEPER MOISTURE AND CLOSER TO THE MID LEVEL CIRCULATION.
THE PRECIPITATION LOOKS TO END THURSDAY NIGHT WITH A DRY DAY
EXPECTED FRIDAY...AS RIDGING ALOFT AND DRYING DEVELOP AHEAD OF NEXT
UPPER TROUGH DROPPING THROUGH THE ROCKIES. STRONG LOW LEVEL JET WILL
PUSH 850 MB TEMPERATURES TO NEAR +8C WHICH WILL SEND TEMPERATURES
WELL ABOVE NORMAL...ESPECIALLY IF ANY SUNSHINE CAN DEVELOP.
ALTHOUGH UPPER 30S COULD LINGER ACROSS THE NORTH COUNTRY...MOST
AREAS WILL HAVE WELL ABOVE NORMAL TEMPERATURES IN THE UPPER 40S TO
LOWER 50S.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
THE MAIN FOCUS FOR THIS PERIOD WILL BE A POTENTIALLY STRONG STORM
SYSTEM PROGGED TO IMPACT THE REGION THIS WEEKEND. MODEL AGREEMENT IS
FAIRLY DECENT ON THE TIMING OF THE CYCLOGENESIS TAKING PLACE OVER THE
SOUTHERN PLAINS EARLY FRIDAY. THIS LOW MOVES UP INTO THE GREAT LAKES
FRIDAY NIGHT WHILE DEEPENING RAPIDLY COURTESY OF A STRONG UPPER
TROUGH IMMEDIATELY UPSTREAM AND A POWERFUL UPPER JET MOVING ACROSS
THE OHIO VALLEY INTO THE NORTHEASTERN U.S.. A VERY STRONG LOW LEVEL
JET WILL ADVECT AN EXTREMELY WARM AIRMASS INTO THE REGION AHEAD OF THE
APPROACHING LOW WITH 850MB TEMPS POTENTIALLY REACHING
+10C...YIELDING HIGHS THAT COULD EASILY REACH INTO THE 50S ON
FRIDAY. FOR FRIDAY NIGHT...INCREASING INSTABILITY AHEAD OF THE
APPROACHING FRONT GIVEN THE EXTREME WARM ADVECTION AND SHOWALTER
INDICES THAT DROP BELOW ZERO AND THE STRONG DYNAMICS ALOFT...HAVE
OPTED TO INCLUDE A MENTION OF THUNDERSTORMS. IN ADDITION...THE
POTENTIAL STRENGTH OF THE SOUTHERLY LOW LEVEL JET WILL CREATE THE
POTENTIAL FOR VERY STRONG WINDS ACROSS HIGH TERRAIN AND DOWNSLOPING
AREAS ALONG LAKE ERIE.
THE LOW PASSES TO OUR NORTHWEST INTO CENTRAL QUEBEC SATURDAY WHILE
SWEEPING A COLD FRONT ACROSS THE REGION. GIVEN THE VERY STRONG LOW
LEVEL JET AHEAD OF THE FRONT AND SUBSIDENCE BEHIND THE FRONT...SEE
THE POTENTIAL FOR ADVISORY TO LOW END WARNING LEVEL WINDS BEHIND THE
FRONT ON SATURDAY. AS ALWAYS THOUGH...IT IS BEST TO BE CAUTIOUS THIS
FAR OUT AS THERE ARE MANY MORE MODEL RUNS TO FINE TUNE THE DETAILS
OF THIS DEVELOPING STORM SYSTEM.
FOR SUNDAY AND MONDAY...THE LONGWAVE UPPER LEVEL TROUGH TRANSITS THE
REGION WITH COLD AIR SWEEPING ACROSS THE REGION USHERING IN A RETURN
TO WINTER. THE COLD ADVECTION WILL BRING A POTENTIAL FOR LAKES SNOWS
THROUGH THE END OF THE WEEKEND AND INTO THE BEGINNING OF NEXT WEEK.
&&
.AVIATION /09Z WEDNESDAY THROUGH SUNDAY/...
EXPECT ONLY HIGH CLOUDS...WITH VFR CONDITIONS TO LAST THROUGH 09Z.
AFTER THIS...PRECIPITATION WILL SPREAD FROM SW TO NE ON WEDNESDAY
MORNING. THIS WILL START AS SNOW OR MIXED
PRECIPITATION...EVENTUALLY TRENDING TO ALL RAIN. MIXED PRECIPITATION
AND SNOW WILL LAST LONGER TO THE NE...LASTING LONGER AT ART/ROC
THAN AT BUF/IAG/JHW. INCREASING MOISTURE WILL LIKELY LOWER ALL
SITES TO IFR OR LOWER AT TIMES WEDNESDAY. STEADY PRECIPITATION
SHOULD TAPER TO SHOWERS LATE AFTERNOON INTO WEDNESDAY EVENING.
OUTLOOK...
WEDNESDAY NIGHT...MVFR IN RAIN...POSSIBLY SNOW NEAR ART.
THURSDAY...MVFR RAIN AND SNOW SHOWERS LIKELY.
FRIDAY...GENERALLY VFR.
SATURDAY...MVFR IN CHC OF SHOWERS.
SUNDAY...VFR/MVFR SCTD SNOW SHOWERS.
&&
.MARINE...
EASTERLY WINDS PICK UP ON THE LAKES LATER TONIGHT INTO WEDNESDAY
MORNING AS A WARM FRONT LIFTS NORTH ACROSS OHIO. WINDS AND WAVES
WILL INCREASE OVER WESTERN LAKE ONTARIO AND WILL WARRANT A SMALL
CRAFT ADVISORY FROM THE NIAGARA RIVER TO SODUS BAY. WINDS WILL
VEER TO THE SOUTH AND DIMINISH DURING THE AFTERNOON ON LAKE
ERIE...WHILE A MORE PERSISTENT EAST SOUTHEAST FLOW REMAINS IN
PLACE ON LAKE ONTARIO.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...WINTER WEATHER ADVISORY FROM 10 AM THIS MORNING TO 4 PM EST
THURSDAY FOR NYZ006>008.
WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR NYZ012-
019>021-085.
WINTER WEATHER ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR
NYZ013-014.
MARINE...SMALL CRAFT ADVISORY FROM 7 AM THIS MORNING TO 4 AM EST
THURSDAY FOR LOZ042-043.
&&
$$
SYNOPSIS...WCH
NEAR TERM...APFFEL/WCH
SHORT TERM...TMA
LONG TERM...WOOD
AVIATION...APFFEL
MARINE...APFFEL/WCH
AREA FORECAST DISCUSSION
NWS BUFFALO NY
1153 PM EST TUE FEB 28 2012
.SYNOPSIS...
HIGH PRESSURE OVER THE EASTERN GREAT LAKES AND NEW YORK STATE WILL
SLIDE TO THE EAST AS LOW PRESSURE OVER THE MIDWEST MOVES EASTWARD.
THERE WILL BE A MIX OF RAIN...SLEET AND SNOW ACROSS PARTS OF WESTERN
AND CENTRAL NEW YORK ON WEDNESDAY MORNING...THEN MAINLY RAIN AND
SNOW FOR THE AFTERNOON. RAIN WILL CHANGE BACK TO SNOW AND TAPER OFF
WEDNESDAY NIGHT.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
THE OVERNIGHT PERIOD WILL BE CLOUDY AND MAINLY DRY. WHILE
COMPOSITE RADAR APPEARS FAIRLY OMINOUS...THE 00Z BUFFALO SOUNDING
SHOWS QUITE DRY AIR BELOW 700 MB. THUS THE MAJORITY OF THE
COMPOSITE RADAR IS ACTUALLY VIRGA. THIS SAID...REFLECTIVITY OF 25
DBZ OR SO SUGGESTS SOME FLURRIES ARE LIKELY REACHING THE GROUND
IN SOME SPOTS. THIS BAND OF MID-UPPER LEVEL WARM AIR ADVECTION
WILL CONTINUE TO LIFT OFF TO THE NORTH...PERHAPS BRINGING A FLURRY
TO BUFFALO AND FAR WESTERN NEW YORK. HOWEVER...THIS SHOULD LIFT TO
THE NORTH SHORTLY AFTER MIDNIGHT...WHILE THE MAIN AREA OF
PRECIPITATION SHOULD NOT ENTER THE REGION UNTIL DAYBREAK. THE 18Z
GFS/12Z RGEM/00Z HRRR ALL BRING IN STEADY PRECIPITATION INTO FAR
WESTERN PORTIONS OF NEW YORK JUST SHY OF 12Z (700 AM). WITH CLOUDS
IN PLACE ACROSS MOST OF THE REGION... TEMPERATURES SHOULD DROP
VERY LITTLE OVERNIGHT.
A WARM FRONT BETWEEN THE DEPARTING HIGH AND APPROACHING LOW WILL
BRING ABOUT A MIX OF WINTRY PRECIP TO PARTS OF WESTERN AND CENTRAL
NY. THIS WILL BRING A BAND OF WARM AIR ADVECTION IN THE LOWER TO
MID LEVELS...WHICH WILL LIFT FROM SOUTHWEST TO NORTHEAST ACROSS THE
REGION ON WEDNESDAY. THERE SHOULD BE A RATHER QUICK CHANGEOVER TO
RAIN IN FAR SOUTHERN SECTIONS...WHERE WINDS SHIFTING TO THE
SOUTHEAST WILL BRING IN WARM AIR ALOFT. FURTHER TO THE NORTH AND
EAST WILL BE FURTHER FROM THE SURFACE LOW AND CLOSER TO COLD HIGH
PRESSURE ANCHORED IN QUEBEC. THIS WILL ALLOW SNOW TO LAST
LONGER INTO WEDNESDAY...WITH LOCATIONS EAST OF LAKE ONTARIO LIKELY
TO STAY SNOW THROUGH SUNSET.
NO CHANGES TO HEADLINES WERE MADE FOR THE EVENING UPDATE. HAVE
SOME CONCERN THAT TEMPERATURES WEDNESDAY MORNING WILL BE SLOW TO
RISE...GIVEN THE INVERSION FORECAST TO DEVELOP BENEATH THE MODEST
SW FLOW ALOFT. THUS DID BUMP DOWN TEMPERATURES A FEW DEGREES ON
WEDNESDAY MORNING. ALSO NUDGED UP SNOW ACCUMULATIONS EAST OF
ROCHESTER. THE 18Z NAM CONTINUES TO BE COLDER THAN THE 18Z GFS AND
MOST OF THE 12Z MODELS...WITH THE SREF TENDING TO SUPPORT THE
WARMER MODEL CAMP AS WELL. A BLEND PROVIDES SIMILAR CHANGEOVER
TIMES TO GOING FORECAST...BUT PERHAPS A TAD MORE QPF BASED ON
LATEST CONSENSUS. EXPECT BETWEEN .25 AND .50 FROM THE BROAD BAND
OF WARM AIR ADVECTION. THIS SHOULD BRING LIGHT ACCUMULATIONS...GENERALLY
2 INCHES OR LESS...WEST OF ROCHESTER...WITH POTENTIAL FOR 2 TO 4
INCHES EAST OF ROCHESTER TO OSWEGO COUNTY THROUGH WEDNESDAY
EVENING.
THE GREATEST POTENTIAL FOR ANY ICE CONTINUES TO BE ACROSS THE
SOUTHERN TIER. WARM AIR ALOFT WILL CROSS QUITE EARLY WEDNESDAY
MORNING...HOWEVER BELOW FREEZING SURFACE TEMPERATURES WILL LIKELY
LINGER WELL INTO THE MORNING. WITH DEW POINTS IN THE UPPER TEENS
AND LOWER 20S...EXPECT SURFACE TEMPERATURES TO DROP EARLY
WEDNESDAY MORNING DUE TO EVAPORATIONAL COOLING. THE ADVISORY
APPEARS TO BE WELL PLACED FOR THIS...WITH A LIGHT GLAZE OF A TENTH
OF AN INCH OR SO OF ICE LIKELY IN THE ADVISORY AREA. IF SURFACE
TEMPERATURES DO LINGER BELOW FREEZING LONGER...IT IS POSSIBLE
ICING TO A QUARTER INCH COULD OCCUR.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/...
A TOUGH FORECASTING SCENARIO FOR WEDNESDAY NIGHT WITH A FAIR AMOUNT
OF UNCERTAINTY ACROSS THE NORTH COUNTRY. THE EVENING STARTS WITH A
WARM FRONT DRAPED ACROSS WESTERN NEW YORK. TEMPERATURES ACROSS MUCH
OF THE FORECAST AREA WILL LIKELY BE ABOVE FREEZING WITH TEMPS
STAYING IN THE MID TO UPPER 30S AND THE ASSOCIATED ISENTROPIC UPLIFT
WILL BRING WIDESPREAD RAINFALL WITH AROUND A TENTH OF AN INCH OF QPF
INT HE WARM SECTOR AS THE PRECIP TAPERS OFF AND THE FOCUS SHIFTS TO
THE NORTH COUNTRY THROUGH THE EVENING HOURS. HEAVIER PRECIP WILL BE
POSSIBLE ACROSS THE NORTH COUNTRY ON THE NOSE OF THE LOW LEVEL JET.
THE BIG QUESTION HERE IS PRECIP TYPE...AS SURFACE TEMPS HERE WILL BE
HOVERING RIGHT AROUND FREEZING. THE NAM KEEPS TEMPERATURES ALOFT MOSTLY
BELOW FREEZING ACROSS THE NORTH COUNTRY FOR THE BULK OF THE
PERIOD...RESULTING IN PRECIP TYPE STAYING MOSTLY SNOW BEFORE
SWITCHING OVER TO RAIN WHEREAS THE GFS BRINGS A MUCH WARMER NOSE
OVER THE AREA SOONER IN THE EVENING...WHICH WOULD RESULT IN A MUCH
GREATER RISK OF FREEZING RAIN AND SLEET. HAVE TRIED TO SHOOT IN THE
MIDDLE FOR NOW WITH A LITTLE BIT OF EVERYTHING AND WILL HOLD OFF ON
AN ADVISORY GIVEN THE UNCERTAINTY REGARDING THE LOCATION/STRENGTH OF
THE WARM NOSE AND THE FACT THAT WE ARE TALKING ABOUT THE THIRD
PERIOD.
COLDER AIR ADVECTS ACROSS THE REGION THURSDAY AS A WEAK COLD FRONT
CROSSES WESTERN NEW YORK. AS THE ASSOCIATED UPPER LOW MOVES OVER THE
AREA...EXPECT RAIN SHOWERS...MIXING WITH SNOW OVER THE HIGHER
ELEVATIONS TO LINGER. TEMPERATURES WILL STAY RELATIVELY MILD WITH
HIGHS IN THE UPPER 30S TO AROUND 40 AS 850MB TEMPS ONLY DROP TO
AROUND -6C. POPS DROP OFF THURSDAY NIGHT AS RIDGING BUILDS OVERHEAD
AND LOWS DROP TO AROUND FREEZING.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
THE MAIN FOCUS FOR THIS PERIOD WILL BE A POTENTIALLY STRONG STORM
SYSTEM PROGGED TO IMPACT THE REGION THIS WEEKEND. MODEL AGREEMENT IS
FAIRLY DECENT ON THE TIMING OF THE CYCLOGENESIS TAKING PLACE OVER THE
SOUTHERN PLAINS EARLY FRIDAY. THIS LOW MOVES UP INTO THE GREAT LAKES
FRIDAY NIGHT WHILE DEEPENING RAPIDLY COURTESY OF A STRONG UPPER
TROUGH IMMEDIATELY UPSTREAM AND A POWERFUL UPPER JET MOVING ACROSS
THE OHIO VALLEY INTO THE NORTHEASTERN U.S.. A VERY STRONG LOW LEVEL
JET WILL ADVECT AN EXTREMELY WARM AIRMASS INTO THE REGION AHEAD OF THE
APPROACHING LOW WITH 850MB TEMPS POTENTIALLY REACHING
+10C...YIELDING HIGHS THAT COULD EASILY REACH INTO THE 50S ON
FRIDAY. FOR FRIDAY NIGHT...INCREASING INSTABILITY AHEAD OF THE
APPROACHING FRONT GIVEN THE EXTREME WARM ADVECTION AND SHOWALTER
INDICES THAT DROP BELOW ZERO AND THE STRONG DYNAMICS ALOFT...HAVE
OPTED TO INCLUDE A MENTION OF THUNDERSTORMS. IN ADDITION...THE
POTENTIAL STRENGTH OF THE SOUTHERLY LOW LEVEL JET WILL CREATE THE
POTENTIAL FOR VERY STRONG WINDS ACROSS HIGH TERRAIN AND DOWNSLOPING
AREAS ALONG LAKE ERIE.
THE LOW PASSES TO OUR NORTHWEST INTO CENTRAL QUEBEC SATURDAY WHILE
SWEEPING A COLD FRONT ACROSS THE REGION. GIVEN THE VERY STRONG LOW
LEVEL JET AHEAD OF THE FRONT AND SUBSIDENCE BEHIND THE FRONT...SEE
THE POTENTIAL FOR ADVISORY TO LOW END WARNING LEVEL WINDS BEHIND THE
FRONT ON SATURDAY. AS ALWAYS THOUGH...IT IS BEST TO BE CAUTIOUS THIS
FAR OUT AS THERE ARE MANY MORE MODEL RUNS TO FINE TUNE THE DETAILS
OF THIS DEVELOPING STORM SYSTEM.
FOR SUNDAY AND MONDAY...THE LONGWAVE UPPER LEVEL TROUGH TRANSITS THE
REGION WITH COLD AIR SWEEPING ACROSS THE REGION USHERING IN A RETURN
TO WINTER. THE COLD ADVECTION WILL BRING A POTENTIAL FOR LAKES SNOWS
THROUGH THE END OF THE WEEKEND AND INTO THE BEGINNING OF NEXT WEEK.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
EXPECT ONLY HIGH CLOUDS...WITH VFR CONDITIONS TO LAST THROUGH 09Z.
AFTER THIS...PRECIPITATION WILL SPREAD FROM SW TO NE ON WEDNESDAY
MORNING. THIS WILL START AS SNOW OR MIXED
PRECIPITATION...EVENTUALLY TRENDING TO ALL RAIN. MIXED PRECIPITATION
AND SNOW WILL LAST LONGER TO THE NE...LASTING LONGER AT ART/ROC
THAN AT BUF/IAG/JHW. INCREASING MOISTURE WILL LIKELY LOWER ALL
SITES TO IFR OR LOWER AT TIMES WEDNESDAY. STEADY PRECIPITATION
SHOULD TAPER TO SHOWERS LATE AFTERNOON INTO WEDNESDAY EVENING.
OUTLOOK...
WEDNESDAY NIGHT...MVFR IN RAIN...POSSIBLY SNOW NEAR ART.
THURSDAY...MVFR RAIN AND SNOW SHOWERS LIKELY.
FRIDAY...GENERALLY VFR.
SATURDAY...MVFR IN CHC OF SHOWERS.
SUNDAY...VFR/MVFR SCTD SNOW SHOWERS.
&&
.MARINE...
EASTERLY WINDS PICK UP ON THE LAKES LATER TONIGHT INTO WEDNESDAY
MORNING AS A WARM FRONT LIFTS NORTH ACROSS OHIO. WINDS AND WAVES
WILL INCREASE OVER WESTERN LAKE ONTARIO AND WILL WARRANT A SMALL
CRAFT ADVISORY FROM THE NIAGARA RIVER TO SODUS BAY. WINDS WILL VEER
TO THE SOUTH AND DIMINISH DURING THE AFTERNOON ON LAKE ERIE...WHILE
A MORE PERSISTENT EAST SOUTHEAST FLOW REMAINS IN PLACE ON LAKE
ONTARIO.
&&
.CLIMATE...
FEBRUARY 2012 HAS BEEN A PERSISTENTLY WARM MONTH...THOUGH NOT DAILY RECORD
WARMTH...THERE HAVE BEEN QUITE A NUMBER OF DAYS THIS MONTH THAT
HAVE REACHED OR EXCEEDED THE FREEZING MARK OF 32F. INCLUDING
TODAY`S MAXIMUM TEMPERATURE...BOTH BUFFALO AND ROCHESTER ARE
NEARING A RECORD NUMBER OF DAYS WITH 32F OR ABOVE MAXIMUM
TEMPERATURES THIS MONTH. WITH 2 DAYS REMAINING THIS FEBRUARY BOTH
CITIES MAY CLIMB HIGHER UP THE LIST. BELOW IS A LIST OF THE YEARS
WITH THE MOST AMOUNT OF FEBRUARY DAYS WITH FREEZING OR HIGHER
TEMPERATURES.
BUFFALO
RANK YEAR NUMBER OF DAYS AT
OR ABOVE FREEZING IN FEBRUARY
1 1998 25
2 2012 23
1884 23
4 1877 22
1890 22
AVG (1871-2012) 14.5
ROCHESTER
RANK YEAR NUMBER OF DAYS AT
OR ABOVE FREEZING IN FEBRUARY
1 1952 24
1998 24
3 2012 23
1931 23
1932 23
AVG (1871-2012) 15.0
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...WINTER WEATHER ADVISORY FROM 5 AM TO NOON EST WEDNESDAY FOR
NYZ012>014-019>021-085.
MARINE...SMALL CRAFT ADVISORY FROM 10 AM TO 11 PM EST WEDNESDAY FOR
LOZ042-043.
&&
$$
SYNOPSIS...WCH
NEAR TERM...APFFEL/WCH
SHORT TERM...WOOD
LONG TERM...WOOD
AVIATION...APFFEL
MARINE...APFFEL/WCH
CLIMATE...THOMAS
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1256 AM EST WED FEB 29 2012
.SYNOPSIS...
HIGH PRESSURE WILL EXTEND INTO THE CAROLINAS OVERNIGHT AND MOVE
OFF THE COAST ON WEDNESDAY. A COLD FRONT WILL MOVE INTO THE
CAROLINAS WEDNESDAY NIGHT AND MAY LINGER NEAR OR JUST SOUTH OF
AREA BEFORE MOVING BACK NORTH AS A WARM FRONT ON FRIDAY. ANOTHER
STRONGER COLD FRONT WILL BRING SHOWERS AND THUNDERSTORMS ON
SATURDAY. COOLER AND DRIER HIGH PRESSURE WILL BUILD INTO THE AREA
SUNDAY INTO EARLY NEXT WEEK BRINGING TEMPERATURES BACK TO
SEASONABLE NORMS AFTER THE MID WEEK WARMTH.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 1:00 AM WEDNESDAY...MID LEVEL DECK INCREASING IN COVERAGE
OVER THE EASTERN CAROLINAS AS EXPECTED. GOING FORECAST LOOKS
FINE...PREVIOUS DISCUSSION FOLLOWS:
SAT IMAGERY AND SFC OBS INDICATE MID LEVEL CLOUD DECK CONTINUES
JUST ON THE SW DOORSTEPS OF THE ILM CWA. MODEL SOUNDINGS INDICATE
PWS INCREASING FROM 1/2 INCH TO NEARLY 1 1/4 INCHES BY DAYBREAK
WEDNESDAY. WHAT THIS SAYS IS THAT THE CLOUDS ON THE WESTERN FRINGE
OF THE ILM CWA WILL FINALLY BE ABLE TO MAKE SOME FORWARD PROGRESS
ACROSS THE ILM CWA. LATEST HRRR MODEL RUNS INDICATE MUCH OF THE
PCPN FALLING APART AS IT APPROACHES THE ILM CWA FROM THE SW THRU W
DURING THE OVERNIGHT. WILL THERE4 RUN WITH THE IDEA OF NO POPS
OVERNIGHT EVEN THOUGH THE PASSAGE OF A DYNAMIC-LESS WARM FRONTAL
BOUNDARY WILL BE ONGOING. WILL EXTRAPOLATE THE AMOUNT OF
CLOUDINESS TO CROSS THE FORECAST AREA FOR THE REMAINDER OF THE
OVERNIGHT WITH THE USE OF SAT IMAGERY TRENDS. PROGGED 8H TEMPS AND
1K-8H THICKNESS INCREASE DRAMATICALLY BETWEEN 1 AM AND 7 AM
WEDNESDAY. COULD BE ONE OF THOSE NIGHTS WHERE THE LOWS ACTUALLY
OCCUR THIS EVENING...FOLLOWED BY TEMPS HOLDING STEADY OR SLOWLY
INCREASING DURING THE OVERNIGHT. COULD SEE ISOLATED -RA OR -SHRA
AHEAD OF THE WFP...OTHER THEN THAT...NO POPS.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH THURSDAY NIGHT/...
AS OF 3 PM TUESDAY...A PERIOD OF UNSETTLED WEATHER IS EXPECTED WED
INTO THU. A DEVELOPING WARM FRONT WILL MOVE ACROSS THE AREA WED
MORNING. A TROUGH OF LOW PRESSURE WILL MOVE ACROSS THE AREA FROM THE
NW ON THU. AHEAD OF THE TROUGH...A DEEP SW TO WSW FLOW IS EXPECTED
TO DEVELOP. PRECIPITABLE WATER VALUES WILL INCREASE TO NEAR AN INCH
AND A HALF AS SW LOW LEVEL JET INCREASES TO 45 KT. TEMPS ON WED...
EVEN WITH CONSIDERABLE CLOUD COVER SHOULD FIND THEIR WAY INTO THE
70S AS H8 TEMPS CLIMB TO AROUND 13 DEG C. ALONG THE COAST...A
RESULTANT SEABREEZE WILL KEEP THE BEACHES COOLEST...UPPER 60S TO
LOWER 70S.
THE BEST SHORTWAVE ENERGY ASSOCIATED WITH THIS SYSTEM WILL TRAVEL TO
OUR DISTANT NORTH LATE WED NIGHT. HOWEVER...THERE SHOULD BE
SUFFICIENT LIFT IN THE WARM SECTOR...AHEAD OF THE TROUGH...TO BRING
A ROUND OF SHOWERS AND THUNDERSTORMS. INSTABILITY WILL BE A LIMITING
FACTOR AND MAINLY ELEVATED GIVEN THE BEST LIFT WILL ARRIVE DURING
THE LATE NIGHT AND EARLY MORNING HOURS. ALSO...A PRONOUNCED LOW
LEVEL INVERSION IS EXPECTED TO DEVELOP AROUND 1000 FT WHICH SHOULD
MAKE IT DIFFICULT FOR HIGHER WINDS ALOFT TO REACH THE SURFACE.
STILL...THE FORECAST AREA REMAINS IN A SLIGHT RISK FOR SEVERE
WEATHER LATE WED NIGHT INTO EARLY THU. STRONG STORMS ARE POSSIBLE
AND IT IS NOT IMPOSSIBLE FOR AN ISOLATED DAMAGING WIND GUST IN THE
STRONGEST STORMS.
TROUGH IS LIKELY TO GET HUNG UP JUST S OF THE FORECAST AREA AS IT
BECOMES PARALLEL TO THE FLOW. THIS WILL KEEP TEMPS WELL ABOVE NORMAL
THROUGH THE PERIOD WITH MORE 70S ON THU...AND AN 80 DEGREE READING
IS NOT OUT OF THE QUESTION AS DRIER AIR WORKS INTO THE AREA ALLOWING
FOR INCREASING SUNSHINE THROUGH THE AFTERNOON. A MORE WESTERLY
COMPONENT TO THE WIND DIRECTION WILL RESULT IN HIGHER TEMPS AT THE
BEACHES THU THAN ON WED. TEMPS BOTH NIGHTS WILL ALSO BE WELL ABOVE
NORMAL WITH WED NIGHT NOT GETTING BELOW THE UPPER 50S TO LOWER 60S.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 3 PM TUESDAY...FOCUS FOR THE EXTENDED REMAINS ON THE FRONT
MOVING ACROSS THE SOUTHEAST SATURDAY THEN A COLDER AIRMASS AND
MINIMUM TEMPERATURES TUESDAY MORNING. HAVE INCREMENTALLY INCREASED
POPS FOR SATURDAY WITH CONFIDENCE A LITTLE HIGHER. STILL LOOKS LIKE
A SLOW TRUDGE ACROSS THE AREA AND WE HAVE POPS FOR SATURDAY AM
THROUGH SUNDAY AM.
BRIEF MID LEVEL TROUGHING MOVES ACROSS QUICKLY SUNDAY THROUGH
TUESDAY WITH A SECONDARY EMBEDDED SHORTWAVE LATE MONDAY INTO EARLY
TUESDAY. THIS FROM THE HPC FAVORED ECMWF. THE LATEST GFS HAS THIS
FEATURE EARLIER. IMPORTANT IMPACT ON LOWER TEMPERATURES TUESDAY
MORNING AS THE BOUNDARY LAYER SHOULD REMAIN WELL MIXED PREVENTING
RADIATIONAL CONDITIONS. ECMWF IS ALSO MORE AGGRESSIVE WITH THE QPF
AND WE MAY HAVE A FEW SPRINKLES/VIRGA TO CONTEND WITH.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
AS OF 06Z...EXPECT VFR THROUGH THE VALID PERIOD...WITH CONDITIONS
POSSIBLY DETERIORATING TO MVFR BEFORE DAYBREAK DUE TO FOG
DEVELOPMENT...AND ADDITIONALLY LOW CIGS AFTER MIDNIGHT THROUGH LATE
MORNING. CURRENT OBS DEPICT AN AREA OF MID TO HIGH LEVEL CLOUDS
SLOWLY INFILTRATING INTO THE SOUTHERN MOST TIP OF OUR AREA IN SC.
ANTICIPATE THESE CLOUDS TO CONTINUE THEIR MIGRATION INTO THE AREA
OVERNIGHT. WITH THE VARYING NATURE OF OPACITY WITH THESE
CLOUDS...THE CONFIDENCE OF TIMING AND OCCURRENCE OF FOG ATTM IS
MODERATE. FOR NOW...IF FOG DOES DEVELOP...BEST CHANCE WILL BE AT
KCRE/KLBT/KFLO AND WILL REMAIN EITHER 4-5SM AND LAST ONLY A FEW
HOURS. GENERALLY EAST WINDS OVERNIGHT WILL BE LIGHT. AFTER
DAYBREAK...LOW STRATOCUMULUS CLOUDS WILL LINGER BEFORE CIGS IMPROVE
TO VFR AGAIN BY LATE AFTERNOON...THOUGH EXPECT CLOUD COVER TO BE
BKN/OVC. CANNOT RULE OUT -DZ...HOWEVER HAVE NOT INTRODUCED INTO
CURRENT FORECAST GIVEN LOW CONFIDENCE. WINDS WILL GRADUALLY BECOME
SOUTHERLY...WITH GUSTS NEAR 20 KTS IN THE LATER AFTERNOON AND
SUBSIDING INTO THE EVENING HOURS. CIGS WILL LOWER AGAIN TOWARDS THE
END OF THE PERIOD CREATING MVFR/IFR CONDITIONS...AND POTENTIALLY
LIFR. HAVE INTRODUCED ISOLATED AREAS OF FOG WITH ENHANCED AREAS OF
MOISTURE...THOUGH CONFIDENCE IS LOW ATTM.
EXTENDED OUTLOOK... A CHANCE FOR PRECIP WEDNESDAY NIGHT INTO
THURSDAY MORNING WITH A COLD FRONT. BECOMING VFR THURSDAY. CHANCE OF
RAIN CONTINUES FOR FRIDAY AND SATURDAY. VFR SUNDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1:00 AM WEDNESDAY...LIGHT NE WINDS AND SEAS IN THE 2 TO 4 FT
RANGE CONTINUE ACROSS THE COASTAL WATERS. NO CHANGES TO GOING
FORECAST...PREVIOUS DISCUSSION FOLLOWS:
EXPECT NE-E WINDS THIS EVENING...AHEAD OF THE WARM FRONT. WINDS
WILL VEER TO THE SE THEN S AFTER THE WFP...WITH IT EXITING NORTH
OF THE LOCAL WATERS BY DAYBREAK WEDNESDAY. WIND SPEEDS WILL RANGE
BETWEEN 10 TO 15 KT...THEN INCREASE TO AROUND 15 KT AFTER THE WFP
DURING THE LATE PRE-DAWN HRS OF WEDNESDAY. SEAS WILL HOLD IN THE 2
TO 4 FT RANGE AND BEGIN TO BUILD DURING THE SHORT TERM.
SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 3 PM TUESDAY...EASTERLY WINDS 10 KTS OR LESS WED MORNING
WILL VEER AROUND TO THE SOUTH AND INCREASE THROUGH WED AHEAD OF
APPROACHING TROUGH. SMALL CRAFT ADVISORY CONDITIONS ARE LIKELY
LATE WED EVE INTO THE FIRST HALF OF THU. SW WINDS WILL INCREASE TO
20 TO 25 KTS WED NIGHT AHEAD OF COLD FRONT. THIS WILL BUILD SEAS
TO 6 TO 7 FT WITH SOME 8 FOOTERS OUT NEAR FRYING PAN SHOALS. WINDS
AND SEAS WILL DIMINISH ON THU AND THIS TREND WILL PERSIST THROUGH
THU NIGHT. WINDS ARE EXPECTED TO REMAIN FROM THE SW FOR MOST OF THE
PERIOD...PERHAPS BRIEFLY VEERING TO WSW LATE THU NIGHT.
LONG TERM /FRIDAY THROUGH SUNDAY/...
AS OF 3 PM TUESDAY...LIGHT FLOW INITIALLY WILL QUICKLY RAMP UP LATER
FRIDAY AND CONTINUE THROUGH SATURDAY AS A FRONT MOVES ACROSS THE
SOUTHEAST. EXPECT A SOUTHWESTERLY FLOW OF 20-25 KNOTS AND ALONG WITH
A SMALL CRAFT ADVISORY TO BEGIN EARLY SATURDAY. THE FRONT MOVES
ACROSS THE WATERS EARLY SUNDAY AND WITHOUT A STRONG SURGE OF COLD
AIR IN ITS WAKE...EXPECT A WESTERLY FLOW OF AROUND 15 KNOTS.
REGARDING SEAS...WILL SEE HIGHEST VALUES...WELL OVER SMALL CRAFT
CRITERIA LATE SATURDAY DIMINISHING WITH THE CHANGE IN FETCH SUNDAY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...REK
AVIATION...SGL
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
548 PM EST WED FEB 29 2012
.SYNOPSIS...
SHOWERS AND THUNDERSTORMS EXIT THE AREA AS A COLD FRONT PUSHES
THROUGH OVERNIGHT BRINGING COOLER AND DRIER AIR FOR TONIGHT AND
THURSDAY. HIGH PRESSURE WILL BUILD INTO THE AREA FOR
THURSDAY...WITH ANOTHER LOW PRESSURE SYSTEM WILL BRING THE
LIKELIHOOD FOR SHOWERS AND THUNDERSTORMS ON FRIDAY.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
THE ONLY CONVECTION REMAINING IN AREA IS JUST SOUTH OF FCST AREA.
STILL SOME THREAT FOR TSTMS FOR SOUTHEAST...WITH STORMS FAST
MOVING AND OVERALL MOVEMENT TAKING THEM OUT OF AREA BY 01Z. CLEARING
WORKING THROUGH AREA...WITH WRAP AROUND CLOUDS ASSOC WITH THE UPR
LOW TO SKIRT ACROSS THE NORTH. TIGHTER PRESS GRADIENT ACROSS THE
NORTH WILL KEEP WIND GUSTS UP THROUGH PART OF THE OVERNIGHT.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
HIGH PRESSURE RISING NORTH FROM THE LOWER MS VALLEY WILL PUSH
PRETTY QUICKLY THROUGH AREA ON THURS. ANOTHER VIGOROUS S/WV WILL
DEVELOP OVER THE MID MS VALLEY AND PUSH TOWARD THE LWR GREAT LAKES
ON FRIDAY. SOME TIMING DIFFERENCES BETWEEN THE SLIGHTLY QUICKER
GFS/ECMWF AND THE MORE ENHANCED/SLOWER NAM. AM STICKING WITH A
BLEND OF THE GFS/ECMWF TIMING SOLUTION...WITH PRECIP BEGINNING
NEAR/AFTER NOON ON FRI. STRONG WAA AHEAD OF THE FRONT WILL BRING
ABOVE NORMAL TEMPS ON FRIDAY...WITH MID TO UPR 60S POSSIBLE. WIND
FIELDS MAINLY 18Z FRI-00Z SAT BRING 50-70+ KTS AT 925-950 HEIGHTS.
STORM MOTIONS SHOULD BE VERY MUCH LIKE TODAY WITH DAMAGING WINDS
POSSIBLE. THREAT LINGERS PAST 00Z...DIMINISHING BY 06Z WITH
APPROACHING FROPA.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
A COLD FRONT WILL BE DEPARTING THE AREA ON SATURDAY
MORNING...BRINGING AN END TO RAINFALL BY EARLY IN THE DAY. BEHIND
THE FRONT...COOL NORTHWESTERLY FLOW WILL SETTLE IN ACROSS THE
REGION. A PASSING SURFACE TROUGH WILL BRING IN A CHANCE OF
PRECIPITATION ON SUNDAY INTO SUNDAY NIGHT...WITH A LARGE UPPER
TROUGH CENTERED JUST EAST OF THE REGION AT THE SAME TIME. THIS WILL
BE A MIX OF RAIN AND SNOW...DEPENDING ON THE TIME OF DAY. THERE ARE
MODEL DIFFERENCES IN THE STRENGTH OF THIS TROUGH AND THE AMOUNT OF
MOISTURE IT WILL BE ABLE TO WORK WITH...WITH THE GFS DEPICTING A
DEEPER AND WETTER SOLUTION. THE HIGHER PRECIPITATION CHANCES WILL
LIKELY BE CLOSER TO THE UPPER SUPPORT...IN THE NORTHEASTERN PART OF
THE CWA.
MODELS ARE THEN IN GOOD AGREEMENT ON HIGH PRESSURE MOVING THROUGH
THE REGION AND SETTLING IN NEAR THE EAST COAST BY THE MIDDLE OF THE
WEEK. THIS WILL PUT THE CWA INTO A PERIOD OF DRY WEATHER AND
PROLONGED SOUTHERLY FLOW...WHICH SHOULD AGAIN BRING TEMPERATURES
WELL ABOVE NORMAL. AT THE SAME TIME...THE LONG WAVE PATTERN WILL
FAVOR RIDGING OVER THE EASTERN HALF OF THE US...WHICH HAS BEEN
FAIRLY STABLY RESOLVED BY MULTIPLE RUNS OF THE GFS/GFSE AS WELL AS
THE ECMWF. DIFFERENCES IN THE EVOLUTION OF THE TROUGHING OVER THE
WESTERN HALF OF THE COUNTRY SHOULD REMAIN MOSTLY IRRELEVANT TO THE
LOCAL FORECAST THROUGH AT LEAST TUESDAY NIGHT...WITH WEDNESDAY BEING
THE EARLIEST THAT A DISTURBANCE MIGHT PUSH EAST INTO THE OHIO VALLEY.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
CONVECTION CONTINUES TO WORK ACROSS KY INTO SOUTH CENTRAL OH IN
THE WARM SECTOR. CVG AND LUK WILL BE AFFECTED BY THE CONVECTION AT
THE ONSET OF THE PERIOD. AT ILN...IT WILL BE CLOSE...BUT AT THIS
TIME WENT WITH A VCSH. LATEST RUC MODEL RUN...IS SHOWING THAT THIS
BATCH OF PCPN IS THE LAST AND THAT REDEVELOPMENT WONT DEVELOP WITH
THE CDFNT LATER THIS MORNING.
DO EXPECT SOME CU DEVELOPMENT WITH THE HEATING AND THESE CLOUDS
WILL LINGER UNTIL AFTER 00Z...WHEN CLEARING WILL WORK IN. WRAP
AROUND CLOUDS ARE FORECAST TO WORK BACK IN LATER TONIGHT. BROUGHT
MVFR CIGS INTO DAY AROUND 06Z. LUK AND CVG WILL BE SIDE SWIPED BY
THESE CLOUDS...SO DONT HAVE THE MVFR CIGS THERE UNTIL 10-11Z.
OUTLOOK...THUNDERSTORMS AND MVFR CIGS/VSBYS POSSIBLE FRIDAY INTO FRIDAY
NIGHT.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...JDR
NEAR TERM...JDR
SHORT TERM...JDR
LONG TERM...HATZOS
AVIATION...SITES
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
403 PM EST WED FEB 29 2012
.SYNOPSIS...
A COLD FRONT PUSHING ACROSS THE AREA THROUGH THIS EVENING WILL
PUSH SHOWERS AND THUNDERSTORMS EAST OF THE AREA THIS EVENING. HIGH
PRESSURE WILL BUILD INTO THE AREA FOR THURSDAY...WITH ANOTHER
LOW PRESSURE SYSTEM WILL BRING THE LIKELIHOOD FOR SHOWERS AND
THUNDERSTORMS ON FRIDAY.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
AREA OF CONVECTION PUSHING RAPIDLY THROUGH AREA. SEVERE THREAT IS
MARGINAL...WITH THE ONLY AREA OF SLIGHT THREAT BEING THE FAR
SOUTHEAST FCST AREA THROUGH ABOUT 22Z. CLEARING WORKING THROUGH
AREA...WITH WRAP AROUND CLOUDS ASSOC WITH THE UPR LOW TO SKIRT
ACROSS THE NORTH. TIGHTER PRESS GRADIENT ACROSS THE NORTH WILL
KEEP WIND GUSTS UP THROUGH PART OF THE OVERNIGHT.
TOR WATCH REMAINS UP IN THE EASTERN FCST AREA THROUGH 02Z...BUT
THREAT IS CONFINED AS MENTIONED ABOVE.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
HIGH PRESSURE RISING NORTH FROM THE LOWER MS VALLEY WILL PUSH
PRETTY QUICKLY THROUGH AREA ON THURS. ANOTHER VIGOROUS S/WV WILL
DEVELOP OVER THE MID MS VALLEY AND PUSH TOWARD THE LWR GREAT LAKES
ON FRIDAY. SOME TIMING DIFFERENCES BETWEEN THE SLIGHTLY QUICKER
GFS/ECMWF AND THE MORE ENHANCED/SLOWER NAM. AM STICKING WITH A
BLEND OF THE GFS/ECMWF TIMING SOLUTION...WITH PRECIP BEGINNING
NEAR/AFTER NOON ON FRI. STRONG WAA AHEAD OF THE FRONT WILL BRING
ABOVE NORMAL TEMPS ON FRIDAY...WITH MID TO UPR 60S POSSIBLE. WIND
FIELDS MAINLY 18Z FRI-00Z SAT BRING 50-70+ KTS AT 925-950 HEIGHTS.
STORM MOTIONS SHOULD BE VERY MUCH LIKE TODAY WITH DAMAGING WINDS
POSSIBLE. THREAT LINGERS PAST 00Z...DIMINISHING BY 06Z WITH
APPROACHING FROPA.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
A COLD FRONT WILL BE DEPARTING THE AREA ON SATURDAY
MORNING...BRINGING AN END TO RAINFALL BY EARLY IN THE DAY. BEHIND
THE FRONT...COOL NORTHWESTERLY FLOW WILL SETTLE IN ACROSS THE
REGION. A PASSING SURFACE TROUGH WILL BRING IN A CHANCE OF
PRECIPITATION ON SUNDAY INTO SUNDAY NIGHT...WITH A LARGE UPPER
TROUGH CENTERED JUST EAST OF THE REGION AT THE SAME TIME. THIS WILL
BE A MIX OF RAIN AND SNOW...DEPENDING ON THE TIME OF DAY. THERE ARE
MODEL DIFFERENCES IN THE STRENGTH OF THIS TROUGH AND THE AMOUNT OF
MOISTURE IT WILL BE ABLE TO WORK WITH...WITH THE GFS DEPICTING A
DEEPER AND WETTER SOLUTION. THE HIGHER PRECIPITATION CHANCES WILL
LIKELY BE CLOSER TO THE UPPER SUPPORT...IN THE NORTHEASTERN PART OF
THE CWA.
MODELS ARE THEN IN GOOD AGREEMENT ON HIGH PRESSURE MOVING THROUGH
THE REGION AND SETTLING IN NEAR THE EAST COAST BY THE MIDDLE OF THE
WEEK. THIS WILL PUT THE CWA INTO A PERIOD OF DRY WEATHER AND
PROLONGED SOUTHERLY FLOW...WHICH SHOULD AGAIN BRING TEMPERATURES
WELL ABOVE NORMAL. AT THE SAME TIME...THE LONG WAVE PATTERN WILL
FAVOR RIDGING OVER THE EASTERN HALF OF THE US...WHICH HAS BEEN
FAIRLY STABLY RESOLVED BY MULTIPLE RUNS OF THE GFS/GFSE AS WELL AS
THE ECMWF. DIFFERENCES IN THE EVOLUTION OF THE TROUGHING OVER THE
WESTERN HALF OF THE COUNTRY SHOULD REMAIN MOSTLY IRRELEVANT TO THE
LOCAL FORECAST THROUGH AT LEAST TUESDAY NIGHT...WITH WEDNESDAY BEING
THE EARLIEST THAT A DISTURBANCE MIGHT PUSH EAST INTO THE OHIO VALLEY.
&&
.AVIATION /21Z WEDNESDAY THROUGH MONDAY/...
CONVECTION CONTINUES TO WORK ACROSS KY INTO SOUTH CENTRAL OH IN
THE WARM SECTOR. CVG AND LUK WILL BE AFFECTED BY THE CONVECTION AT
THE ONSET OF THE PERIOD. AT ILN...IT WILL BE CLOSE...BUT AT THIS
TIME WENT WITH A VCSH. LATEST RUC MODEL RUN...IS SHOWING THAT THIS
BATCH OF PCPN IS THE LAST AND THAT REDEVELOPMENT WONT DEVELOP WITH
THE CDFNT LATER THIS MORNING.
DO EXPECT SOME CU DEVELOPMENT WITH THE HEATING AND THESE CLOUDS
WILL LINGER UNTIL AFTER 00Z...WHEN CLEARING WILL WORK IN. WRAP
AROUND CLOUDS ARE FORECAST TO WORK BACK IN LATER TONIGHT. BROUGHT
MVFR CIGS INTO DAY AROUND 06Z. LUK AND CVG WILL BE SIDE SWIPED BY
THESE CLOUDS...SO DONT HAVE THE MVFR CIGS THERE UNTIL 10-11Z.
OUTLOOK...THUNDERSTORMS AND MVFR CIGS/VSBYS POSSIBLE FRIDAY INTO FRIDAY
NIGHT.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...JDR
NEAR TERM...JDR
SHORT TERM...JDR
LONG TERM...HATZOS
AVIATION...SITES
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
116 PM EST WED FEB 29 2012
.SYNOPSIS...
A COLD FRONT WORK ACROSS THE AREA THIS AFTERNOON AND
EVENING...BRINGING A CHANCE OF SHOWERS AND THUNDERSTORMS TO MAINLY
SOUTHERN OHIO AND NORTHERN KENTUCKY. HIGH PRESSURE AND DRY AIR
WILL MOVE IN TONIGHT THROUGH THURSDAY. ANOTHER LOW PRESSURE SYSTEM
WILL BRING THE LIKELIHOOD FOR SHOWERS AND THUNDERSTORMS ON FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THIRD ROUND OF CONVECTION IS WORKING ACROSS THE SRN PORTION OF THE
FA ATTM. LATEST RUNS OF THE RUC AND HRRR ARE INDICATING THAT AS
THE CDFNT TO THE W WORKS E THIS AFTN...THAT ADDITIONAL CONVECTION
WILL AFFECT NRN KY INTO SRN OHIO. BACKED OFF THE THE PCPN ACROSS
THE N FOR THIS AFTN BASED ON THESE RUNS.
TOR WATCH REMAINS UP AFTER COORDINATION WITH SPC. THEY WANTED TO
LEAVE IT UP TO COVER THE POSSIBILITY OF REDEVELOPMENT LATE THIS
MORNING INTO AFTN.
KEPT HIGHS INTO THE MID TO UPPER 60S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
A COLD FRONT WILL BE MOVING ACROSS THE AREA EARLY THIS
EVENING...WITH THUNDERSTORMS LIKELY AND DAMAGING WINDS POSSIBLE.
ACTIVITY WILL END BY LATE EVENING AS THE FRONT DEPARTS TO THE
EAST AND HIGH PRESSURE STARTS TO BUILD IN. THE HIGH WILL PROVIDE
DRY CONDITIONS AS IT MOVES ACROSS OHIO THURSDAY AND THURSDAY
NIGHT. THOUGH THERE WILL BE A BRIEF PERIOD OF COLD ADVECTION ON
THURSDAY...TEMPERATURES WILL STAY ABOVE NORMAL WITH HIGHS MAINLY IN
THE 50S.
ANOTHER LOW WILL DRAG A VIGOROUS COLD FRONT TO THE REGION ON
FRIDAY. WIND FIELDS ASSOCIATED WITH THE FAST MOVING COLD FRONT
SUGGEST STORM MOTIONS OF 50 KNOTS WHICH COULD YIELD DAMAGING WIND
GUSTS. STRONG WARM ADVECTION AHEAD OF THE COLD FRONT WILL CAUSE
TEMPERATURES TO BE WELL ABOVE NORMAL...WITH HIGHS REACHING THE
60S.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
THE AREA WILL THEN REMAIN UNDER NORTHWESTERLY UPPER LEVEL FLOW
OVER THE WEEKEND. THIS WILL BRING A COUPLE OF WEAK DISTURBANCES
ACROSS OUR AREA WITH CHANCES FOR RAIN/SNOW SHOWERS. TEMPERATURES
OVER THE WEEKEND WILL BE SEASONABLY COOL AS WE REMAIN UNDER THE
WESTERN EDGE OF A LARGE UPPER TROUGH. SURFACE HIGH PRESSURE WILL
BUILD ACROSS THE REGION BY LATE IN THE WEEKEND AND WILL SLOWLY
SLIDE EASTWARD INTO THE BEGINNING OF NEXT WEEK. THIS WILL PRODUCE
A WARMING TREND TO START OFF THE WEEK...WITH ABOVE NORMAL
TEMPERATURES EXPECTED BY MID WEEK.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
CONVECTION CONTINUES TO WORK ACROSS KY INTO SOUTH CENTRAL OH IN
THE WARM SECTOR. CVG AND LUK WILL BE AFFECTED BY THE CONVECTION AT
THE ONSET OF THE PERIOD. AT ILN...IT WILL BE CLOSE...BUT AT THIS
TIME WENT WITH A VCSH. LATEST RUC MODEL RUN...IS SHOWING THAT THIS
BATCH OF PCPN IS THE LAST AND THAT REDEVELOPMENT WONT DEVELOP WITH
THE CDFNT LATER THIS MORNING.
DO EXPECT SOME CU DEVELOPMENT WITH THE HEATING AND THESE CLOUDS
WILL LINGER UNTIL AFTER 00Z...WHEN CLEARING WILL WORK IN. WRAP
AROUND CLOUDS ARE FORECAST TO WORK BACK IN LATER TONIGHT. BROUGHT
MVFR CIGS INTO DAY AROUND 06Z. LUK AND CVG WILL BE SIDE SWIPED BY
THESE CLOUDS...SO DONT HAVE THE MVFR CIGS THERE UNTIL 10-11Z.
OUTLOOK...THUNDERSTORMS AND MVFR CIGS/VSBYS POSSIBLE FRIDAY INTO FRIDAY
NIGHT.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...CONIGLIO
NEAR TERM...SITES
SHORT TERM...CONIGLIO
LONG TERM...LATTO
AVIATION...SITES
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
1138 AM EST WED FEB 29 2012
.SYNOPSIS...
A COLD FRONT WORK ACROSS THE AREA THIS AFTERNOON AND
EVENING...BRINGING A CHANCE OF SHOWERS AND THUNDERSTORMS TO MAINLY
SOUTHERN OHIO AND NORTHERN KENTUCKY. HIGH PRESSURE AND DRY AIR
WILL MOVE IN TONIGHT THROUGH THURSDAY. ANOTHER LOW PRESSURE SYSTEM
WILL BRING THE LIKELIHOOD FOR SHOWERS AND THUNDERSTORMS ON FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THIRD ROUND OF CONVECTION IS WORKING ACROSS THE SRN PORTION OF THE
FA ATTM. LATEST RUNS OF THE RUC AND HRRR ARE INDICATING THAT AS
THE CDFNT TO THE W WORKS E THIS AFTN...THAT ADDITIONAL CONVECTION
WILL AFFECT NRN KY INTO SRN OHIO. BACKED OFF THE THE PCPN ACROSS
THE N FOR THIS AFTN BASED ON THESE RUNS.
TOR WATCH REMAINS UP AFTER COORDINATION WITH SPC. THEY WANTED TO
LEAVE IT UP TO COVER THE POSSIBILTY OF REDEVELOPEMENT LATE THIS
MORNING INTO AFTN.
KEPT HIGHS INTO THE MID TO UPPER 60S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
A COLD FRONT WILL BE MOVING ACROSS THE AREA EARLY THIS
EVENING...WITH THUNDERSTORMS LIKELY AND DAMAGING WINDS POSSIBLE.
ACTIVITY WILL END BY LATE EVENING AS THE FRONT DEPARTS TO THE
EAST AND HIGH PRESSURE STARTS TO BUILD IN. THE HIGH WILL PROVIDE
DRY CONDITIONS AS IT MOVES ACROSS OHIO THURSDAY AND THURSDAY
NIGHT. THOUGH THERE WILL BE A BRIEF PERIOD OF COLD ADVECTION ON
THURSDAY...TEMPERATURES WILL STAY ABOVE NORMAL WITH HIGHS MAINLY IN
THE 50S.
ANOTHER LOW WILL DRAG A VIGOROUS COLD FRONT TO THE REGION ON
FRIDAY. WIND FIELDS ASSOCIATED WITH THE FAST MOVING COLD FRONT
SUGGEST STORM MOTIONS OF 50 KNOTS WHICH COULD YIELD DAMAGING WIND
GUSTS. STRONG WARM ADVECTION AHEAD OF THE COLD FRONT WILL CAUSE
TEMPERATURES TO BE WELL ABOVE NORMAL...WITH HIGHS REACHING THE
60S.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
THE AREA WILL THEN REMAIN UNDER NORTHWESTERLY UPPER LEVEL FLOW
OVER THE WEEKEND. THIS WILL BRING A COUPLE OF WEAK DISTURBANCES
ACROSS OUR AREA WITH CHANCES FOR RAIN/SNOW SHOWERS. TEMPERATURES
OVER THE WEEKEND WILL BE SEASONABLY COOL AS WE REMAIN UNDER THE
WESTERN EDGE OF A LARGE UPPER TROUGH. SURFACE HIGH PRESSURE WILL
BUILD ACROSS THE REGION BY LATE IN THE WEEKEND AND WILL SLOWLY
SLIDE EASTWARD INTO THE BEGINNING OF NEXT WEEK. THIS WILL PRODUCE
A WARMING TREND TO START OFF THE WEEK...WITH ABOVE NORMAL
TEMPERATURES EXPECTED BY MID WEEK.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
A WARM FRONT LIFTING NORTH INTO SRN OHIO ALONG WITH A STRONG
LOW LEVEL JET AND ELEVATED INSTBY HAS LED TO WIDESPREAD SHOWERS
AND EMBEDDED THUNDERSTORMS. CIGS HAVE DROPPED INTO THE MVFR CATEGORY
WITH OCCASIONAL IFR CIGS EXPECTED EARLY THIS MORNING.
THE WARM FRONT TO CONTINUE LIFTING NORTH THRU THE TAF SITES THIS
MORNING WITH ALL TAFS GETTING IN THE WARM SECTOR. THIS SHOULD
ALLOW FOR WIDESPREAD SHOWERS TO TAPER OFF THROUGH MID TO LATE
MORNING WITH SOME IMPROVEMENT IN CIGS LKLY. NUMERICAL MODELS CONTINUE
TO SHOW A NARROW BAND OF INSTBY NOSING UP INTO THE REGION DURG THE
LATE MORNING INTO THE AFTN...AHEAD OF AN APPROACHING COLD FRONT.
NAM SOLN CONTINUES TO BE MORE UNSTBL THAN GFS. HAVE A MENTION OF THUNDER
WITH MVFR CIGS AT ALL TAF SITES INTO MID AFTN.
WINDS WILL VEER TO THE SOUTHWEST THIS AFTN WITH GUSTS AS HIGH AS
28 KTS.
OUTLOOK...THUNDERSTORMS AND MVFR CIGS/VSBYS POSSIBLE FRIDAY INTO FRIDAY
NIGHT.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...CONIGLIO
NEAR TERM...SITES
SHORT TERM...CONIGLIO
LONG TERM...LATTO
AVIATION...AR
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
336 PM EST WED FEB 29 2012
.SYNOPSIS...
A STRONG COLD FRONT WILL IMPACT THE REGION THROUGH TONIGHT AND MOVES
OFF TO THE EAST THURSDAY MORNING. ANOTHER COLD FRONT IS EXPECTED TO
AFFECT THE CAROLINAS AND NORTHEAST GEORGIA FRIDAY INTO SATURDAY.
HIGH PRESSURE WILL BUILD OVER THE REGION SUNDAY AND LINGER INTO THE
EARLY PART OF NEXT WEEK.
&&
.NEAR TERM /THROUGH THURSDAY/...
AT 230 PM EST...LOW STRATUS AND PATCHY DRIZZLE STUBBORNLY HANGING ON
IN NE GA AND THER WESTERN UPSTATE IN THE WEAKLY CONVERGENT LOW
LEVEL FLOW. LIGHT RADAR RETURNS CONTINUE TO DEPICT THE DRIZZLE.
LATEST HRRR INDICATES THAT THIS SHOULD PERSIST FOR ANOTHER COUPLE
HOURS AND WILL CONTINUE TO INCLUDE IN THE WEATHER GRIDS. CLOUD BASES
STILL EXPECTED TO RISE LATE THIS AFTERNOON AS BETTER MIXING DEVELOPS.
12Z MODEL SOUNDINGS INDICATE THAT THE THREAT OF ANY CONVECTION
THIS AFTERNOON IS QUITE LOW DUE TO A CAP...SO HAVE LOWERED POPS FOR
LATE AFTERNOON PERIOD.
A POSSIBLE ROBUST SEVERE THREAT WILL EXIST TONIGHT AS A COLD FRONT
AND ATTENDENT CONVECTION MOVES ACROSS WESTERN CAROLINAS AND NE GA.
SPC HAS A MODERATE RISK EXTENDING INTO FAR WESTERN NC WITH A SLIGHT
RISK ELSEWHERE. LOOKS LIKE A DAMAGING WIND THREAT IS THE GREATEST
RISK...BUT HIGH HELICITIES SUPPORT AN ISOLATED TORNADO THREAT AS
WELL. LOOKS LIKE A BROKEN LINE OF THUNDERSTORMS...SOME POSSIBLY
SEVERE WILL MOVE THROUGH IN THE 00Z TO 06Z TIME FRAME. THE
CONVECTION ENTERING THE MOUNTAINS...WILL PROBABLY TEND TO WEAKEN AS
IT MOVES EASTWARD AS WINDS WILL HAVE A SOMEWHAT DWONSLOPING
COMPONENT...PLUS CAPES WILL BE DIURNALLY TRENDING DOWN AS WELL. WILL
HAVE TO WATCH FOR STRONG TO SEVERE CONVECTION MOVING OUT OF NORTHERN
AL/GA THAT COULD AFFECT THE PIEDMONT AREAS. CONVECTION/FRONT SHOULD
CLEAR THE FORECAST AREA AROUND 06Z WITH PARTIAL CLEARING COMMENCING
LATE TONIGHT.
THURSDAY IS SHAPING UP AS A VERY NICE DAY DAY AS THE FRONT LAYS OUT
TO THE SOUTH OF THE AREA AND HIGH PRESSURE BUILDS OVER THE AREA.
PLENTY SUNSHINE COUPLED WITH DOWNSLOPE FLOW WILL SEND TEMPS INTO THE
MID TO UPPER 70S OUTSIDE THE MOUTNAINS TO AROUND 70 MOUNTAIN
VALLEYS. ALTHOUGH IT WILL BE QUITE WARM...IT WILL NOT REACH RECORD
LEVELS.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
AS OF 230 PM WEDNESDAY...THE FIRST PART OF WEEKEND LOOKS ACTIVE. THE
OLD SURFACE FRONT TO OUR SOUTH WILL SPRING BACK TO LIFE THURSDAY
EVENING AS MOISTURE RETURNS FROM THE GULF AND VEERING WIND AT 850 MB
BRINGS RENEWED ISENTROPIC UPGLIDE ON THE 300K SURFACE. THE NEWLY
ACTIVITATED WARM FRONT SHOULD APPROACH FROM THE SOUTH WITH LIGHT
PRECIP BREAKING OUT FROM SOUTH TO NORTH IN THE PREDAWN HOURS...
PERHAPS ONLY WEST OF I-26 WHERE A CHANCE WILL BE CARRIED. THE
UPGLIDE AND WARM ADVECTION CONTINUES THROUGH FRIDAY AS THE WARM
FRONT LIFTS NORTHWARD...SO THE PRECIP CHANCES SPREAD ACROSS THE
REMAINDER OF THE FCST AREA...WITH A LIKELY POP ACROSS THE MTNS WHERE
THE MOST FAVORABLE UPSLOPE FLOW SHOULD BE. THIS FCST IS NOT WITHOUT
ITS POTENTIAL BUST WHERE TEMPS ARE CONCERNED. THE NAM HOLDS ONTO A
STRONGER PARENT HIGH OVER NEW ENGLAND...WHICH CONTRIBUTES TO A COLD
AIR DAMMING WEDGE E OF THE BLUE RIDGE...WHEREAS THE SURFACE HIGH ON
THE GFS IS MUCH WEAKER. AT THIS POINT...THE GFS LOOKS LIKE THE
BETTER CHOICE WITHOUT MUCH SEEN TO ANCHOR A HIGH TO OUR NE ON
FRIDAY. TEMPS WERE NUDGED A DEGREE OR TWO LOWER IN THE USUAL CAD
REGION TO HEDGE OUR BETS...BUT FOR THE MOST PART THE GFS IS
PREFERRED.
THE NEXT UPPER TROF WILL FEATURE AN ELONGATED AND POSTIVELY TILTED
SHORT WAVE ON SATURDAY THAT DIGS MUCH FARTHER S THAN TODAYS SYSTEM.
THE UPPER FORCING WILL GRADUALLY IMPROVE LATE FRIDAY NIGHT AND
SATURDAY MORNING IN ADVANCE OF A STRONG COLD FRONT. PRECIP CHANCES
ARE RAMPED BACK UP TO LIKELY ACROSS THE MTNS BEFORE SUNRISE. THERE
IS SOME UNCERTAINTY WITH THE TIMING OF THE FRONTAL PASSAGE...WHICH
IS MOST LIKELY SATURDAY DURING THE DAY. THE TREND HAS BEEN TO SLOW
THINGS DOWN BY A FEW HOURS. A CONTINUATION OF THIS TREND WILL BE THE
KEY TO DETERMINING OUR SEVERE WEATHER THREAT. THE MODELS MANAGE TO
DEVELOP STRONG MAINLY UNIDIRECTIONAL SHEAR ON SATURDAY AHEAD OF
FROPA...BUT LIMITED BUOYANCY BECAUSE OF THE TIMING. CAPE ON THE NAM
IS MEAGER AT BEST...AND MINIMAL ON THE GFS...FOR NOW. IF THE TIMING
SLIPS FURTHER...WE COULD HAVE A VERY INTERESTING SEVERE WEATHER
THREAT IN THE AFTERNOON EAST OF THE MTNS. PRECIP CHANCES WERE KEPT
TO LIKELY WITH FROPA OVER TIMING UNCERTAINTY...AND ENDED FROM THE
WEST LATE IN THE DAY. THERE IS SOME CARRYOVER INTO SATURDAY EVENING
BASED ON TIMING TREND...BUT THE FRONT SHOULD BE EAST OF THE REGION
BY MID EVENING AT THE LATEST.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 200 PM WEDNESDAY...THE LATEST MEDIUM RANGE MODELS SUGGEST THAT
A COLD FRONT WILL MOVE OFF THE ATLANTIC COAST BY 12Z SUNDAY BEFORE A
WEAK UPPER SHORTWAVE SWINGS ACROSS THE NORTHERN PART OF OUR CWFA BY
SUNDAY AFTERNOON. THEREFORE...CLEARING SKIES CAN BE EXPECTED MAINLY
OVER THE LOWER PIEDMONT WHILE PORTIONS OF NC MOUNTAINS COULD SEE
INCREASING CLOUDINESS WITH LIGHT PRECIP DEVELOPING OVER THE AREA ON
SUNDAY AFTERNOON. PRECIPITATION WILL BE MAINLY LIQUID AS THE TEMPS
REMAIN ABOVE FREEZING IN THE AFTERNOON. AS THE SHORTWAVE MOVES OFF
TO THE EAST...A CANADIAN SURFACE HIGH WILL BUILD INTO THE REGION
LATE SUNDAY AND LINGER INTO EARLY PART OF NEXT WEEK. HENCE...MOSTLY
DRY CONDITIONS WITH MODERATING TEMPERATURES ARE EXPECTED SUNDAY
NIGHT THROUGH TUESDAY. WEDNESDAY...A MOIST SOUTHERLY FLOW WILL
INCREASE OVER OUR AREA IN ADVANCE OF APPROACHING COLD FRONT FROM THE
WEST. PRECIP WILL DEVELOP BY LATE WEDNESDAY IN RESPOND TO ISENTROPIC
LIFTING OVER THE REGION. HOWEVER...I HAVE LIMITED POPS TO SLIGHT
CHANCE LATE WED/THU DUE TO THE UNCERTAINTY. TEMPERATURES WILL REMAIN
3-5 DEGREES BELOW THE SEASONAL AVERAGES SUN/MON AND RISE ABOVE
NORMALS TUE/WED.
&&
.AVIATION /21Z WEDNESDAY THROUGH MONDAY/...
AT KCLT...IFR CONDITIONS CONTINUE AT MID-AFTERNOON. GUIDANCE
CONTINUE TO SUGGEST THAT CIGS WILL GRADUALLY INCREASE INTO THE MVFR
RANGE BY 20Z AND THEN ESSENTIALLY HOLD THERE. AN AREA OF DRIZZLE
ACROSS UPSTATE SC COULD PUT A WRENCH IN THIS THINKING AS VSBYS`S
HAVE CRASHED TO 2 MILES WITHIN IT WITH LIFR CIGS. HOWEVER...WILL BANK ON
IT DISSIPATING AS IT PROGRESSES E. AFTER 00Z...EXPECT A BROKEN LINE
OF THUNDERSTORMS TO APPROACH AND WILL CARRY A PERIOD OF TSRA IN THE
03Z-05Z TIMEFRAME. THE THREAT FOR A SEVERE STORM IS POSSIBLE...BUT
PROB TOO LOW AT THIS POINT TO PUT IN THE TAF. THE CONVECTION WILL
MOVE EAST OF THE AREA BY 06Z...WITH CONDITIONS IMPROVING TO VFR BY
09Z.
ELSEWHERE...PESKY LIFR STILL HANGING IN AT EARLY AFTERNOON. AREA OF
DRIZZLE OVER THE UPSTATE HAS LOWERED CIG/VSBY AT KGSP/KGMU AGAIN.
EXPECT THAT ONCE THIS MOVES EAST SOME RAPID IMPROVEMENT SHOULD
COMMENCE WITH CIGS IMPROVING TO MVFR AND VSBY TO VFR BY 21Z AS
MIXING IMPROVES. AT KAVL...GUIDANCE SUGGESTS THAT CURRENT VFR CONDITIONS
WILL FILL IN WITH MVFR BY 20Z OR SO. AFTER 00Z...A BROKEN LINE OF
THUNDERSTORMS WILL APPROACH FROM THE W-NW AND WILL CARRY A PERIOD OF
THUNDER AT ALL TAF SITES. A SEVERE STORMS ARE POSSIBLE...BUT PROB TOO
LOW TO PUT IN TAFS AT THE MOMENT. ONCE THE FRONT AND ASSOCIATION
CONVECTION MOVES EAST BY 05Z...EXPECT CONDITIONS TO IMPROVE TO VFR.
OUTLOOK...VFR/DRY WEATHER WILL CONTINUE INTO THU NIGHT. HOWEVER...BY
LATE THU NIGHT...MOISTURE WILL INCREASE YET AGAIN AS ANOTHER STORM
SYSTEM APPROACHES THE REGION FROM THE WEST. CHANCES FOR SHOWERS/FLT
RESTRICTIONS WILL PERSIST THROUGH AT LEAST SATURDAY MORNING. DRY
WEATHER SHOULD RETURN BY THE END OF THE WEEKEND.
AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)...
WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...JOH
NEAR TERM...LG
SHORT TERM...PM
LONG TERM...JOH
AVIATION...LG
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
252 PM EST WED FEB 29 2012
.SYNOPSIS...
A STRONG COLD FRONT WILL IMPACT THE REGION THROUGH TONIGHT AND MOVES
OFF TO THE EAST THURSDAY MORNING. ANOTHER COLD FRONT IS EXPECTED TO
AFFECT THE CAROLINAS AND NORTHEAST GEORGIA FRIDAY INTO SATURDAY.
HIGH PRESSURE WILL BUILD OVER THE REGION SUNDAY AND LINGER INTO THE
EARLY PART OF NEXT WEEK.
&&
.NEAR TERM /THROUGH THURSDAY/...
AT 230 PM EST...LOW STRATUS AND PATCHY DRIZZLE STUBBORNLY HANGING ON
IN NE GA AND THER WESTERN UPSTATE IN THE WEAKLY CONVERGENT LOW
LEVEL FLOW. LIGHT RADAR RETURNS CONTINUE TO DEPICT THE DRIZZLE.
LATEST HRRR INDICATES THAT THIS SHOULD PERSIST FOR ANOTHER COUPLE
HOURS AND WILL CONTINUE TO INCLUDE IN THE WEATHER GRIDS. CLOUD BASES
STILL EXPECTED TO RISE LATE THIS AFTERNOON AS BETTER MIXING DEVELOPS.
12Z MODEL SOUNDINGS INDICATE THAT THE THREAT OF ANY CONVECTION
THIS AFTERNOON IS QUITE LOW DUE TO A CAP...SO HAVE LOWERED POPS FOR
LATE AFTERNOON PERIOD.
A POSSIBLE ROBUST SEVERE THREAT WILL EXIST TONIGHT AS A COLD FRONT
AND ATTENDENT CONVECTION MOVES ACROSS WESTERN CAROLINAS AND NE GA.
SPC HAS A MODERATE RISK EXTENDING INTO FAR WESTERN NC WITH A SLIGHT
RISK ELSEWHERE. LOOKS LIKE A DAMAGING WIND THREAT IS THE GREATEST
RISK...BUT HIGH HELICITIES SUPPORT AN ISOLATED TORNADO THREAT AS
WELL. LOOKS LIKE A BROKEN LINE OF THUNDERSTORMS...SOME POSSIBLY
SEVERE WILL MOVE THROUGH IN THE 00Z TO 06Z TIME FRAME. THE
CONVECTION ENTERING THE MOUNTAINS...WILL PROBABLY TEND TO WEAKEN AS
IT MOVES EASTWARD AS WINDS WILL HAVE A SOMEWHAT DWONSLOPING
COMPONENT...PLUS CAPES WILL BE DIURNALLY TRENDING DOWN AS WELL. WILL
HAVE TO WATCH FOR STRONG TO SEVERE CONVECTION MOVING OUT OF NORTHERN
AL/GA THAT COULD AFFECT THE PIEDMONT AREAS. CONVECTION/FRONT SHOULD
CLEAR THE FORECAST AREA AROUND 06Z WITH PARTIAL CLEARING COMMENCING
LATE TONIGHT.
THURSDAY IS SHAPING UP AS A VERY NICE DAY DAY AS THE FRONT LAYS OUT
TO THE SOUTH OF THE AREA AND HIGH PRESSURE BUILDS OVER THE AREA.
PLENTY SUNSHINE COUPLED WITH DOWNSLOPE FLOW WILL SEND TEMPS INTO THE
MID TO UPPER 70S OUTSIDE THE MOUTNAINS TO AROUND 70 MOUNTAIN
VALLEYS. ALTHOUGH IT WILL BE QUITE WARM...IT WILL NOT REACH RECORD
LEVELS.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
AS OF 230 PM WEDNESDAY...THE FIRST PART OF WEEKEND LOOKS ACTIVE. THE
OLD SURFACE FRONT TO OUR SOUTH WILL SPRING BACK TO LIFE THURSDAY
EVENING AS MOISTURE RETURNS FROM THE GULF AND VEERING WIND AT 850 MB
BRINGS RENEWED ISENTROPIC UPGLIDE ON THE 300K SURFACE. THE NEWLY
ACTIVITATED WARM FRONT SHOULD APPROACH FROM THE SOUTH WITH LIGHT
PRECIP BREAKING OUT FROM SOUTH TO NORTH IN THE PREDAWN HOURS...
PERHAPS ONLY WEST OF I-26 WHERE A CHANCE WILL BE CARRIED. THE
UPGLIDE AND WARM ADVECTION CONTINUES THROUGH FRIDAY AS THE WARM
FRONT LIFTS NORTHWARD...SO THE PRECIP CHANCES SPREAD ACROSS THE
REMAINDER OF THE FCST AREA...WITH A LIKELY POP ACROSS THE MTNS WHERE
THE MOST FAVORABLE UPSLOPE FLOW SHOULD BE. THIS FCST IS NOT WITHOUT
ITS POTENTIAL BUST WHERE TEMPS ARE CONCERNED. THE NAM HOLDS ONTO A
STRONGER PARENT HIGH OVER NEW ENGLAND...WHICH CONTRIBUTES TO A COLD
AIR DAMMING WEDGE E OF THE BLUE RIDGE...WHEREAS THE SURFACE HIGH ON
THE GFS IS MUCH WEAKER. AT THIS POINT...THE GFS LOOKS LIKE THE
BETTER CHOICE WITHOUT MUCH SEEN TO ANCHOR A HIGH TO OUR NE ON
FRIDAY. TEMPS WERE NUDGED A DEGREE OR TWO LOWER IN THE USUAL CAD
REGION TO HEDGE OUR BETS...BUT FOR THE MOST PART THE GFS IS
PREFERRED.
THE NEXT UPPER TROF WILL FEATURE AN ELONGATED AND POSTIVELY TILTED
SHORT WAVE ON SATURDAY THAT DIGS MUCH FARTHER S THAN TODAYS SYSTEM.
THE UPPER FORCING WILL GRADUALLY IMPROVE LATE FRIDAY NIGHT AND
SATURDAY MORNING IN ADVANCE OF A STRONG COLD FRONT. PRECIP CHANCES
ARE RAMPED BACK UP TO LIKELY ACROSS THE MTNS BEFORE SUNRISE. THERE
IS SOME UNCERTAINTY WITH THE TIMING OF THE FRONTAL PASSAGE...WHICH
IS MOST LIKELY SATURDAY DURING THE DAY. THE TREND HAS BEEN TO SLOW
THINGS DOWN BY A FEW HOURS. A CONTINUATION OF THIS TREND WILL BE THE
KEY TO DETERMINING OUR SEVERE WEATHER THREAT. THE MODELS MANAGE TO
DEVELOP STRONG MAINLY UNIDIRECTIONAL SHEAR ON SATURDAY AHEAD OF
FROPA...BUT LIMITED BUOYANCY BECAUSE OF THE TIMING. CAPE ON THE NAM
IS MEAGER AT BEST...AND MINIMAL ON THE GFS...FOR NOW. IF THE TIMING
SLIPS FURTHER...WE COULD HAVE A VERY INTERESTING SEVERE WEATHER
THREAT IN THE AFTERNOON EAST OF THE MTNS. PRECIP CHANCES WERE KEPT
TO LIKELY WITH FROPA OVER TIMING UNCERTAINTY...AND ENDED FROM THE
WEST LATE IN THE DAY. THERE IS SOME CARRYOVER INTO SATURDAY EVENING
BASED ON TIMING TREND...BUT THE FRONT SHOULD BE EAST OF THE REGION
BY MID EVENING AT THE LATEST.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 200 PM WEDNESDAY...THE LATEST MEDIUM RANGE MODELS SUGGEST THAT
A COLD FRONT WILL MOVE OFF THE ATLANTIC COAST BY 12Z SUNDAY BEFORE A
WEAK UPPER SHORTWAVE SWINGS ACROSS THE NORTHERN PART OF OUR CWFA BY
SUNDAY AFTERNOON. THEREFORE...CLEARING SKIES CAN BE EXPECTED MAINLY
OVER THE LOWER PIEDMONT WHILE PORTIONS OF NC MOUNTAINS COULD SEE
INCREASING CLOUDINESS WITH LIGHT PRECIP DEVELOPING OVER THE AREA ON
SUNDAY AFTERNOON. PRECIPITATION WILL BE MAINLY LIQUID AS THE TEMPS
REMAIN ABOVE FREEZING IN THE AFTERNOON. AS THE SHORTWAVE MOVES OFF
TO THE EAST...A CANADIAN SURFACE HIGH WILL BUILD INTO THE REGION
LATE SUNDAY AND LINGER INTO EARLY PART OF NEXT WEEK. HENCE...MOSTLY
DRY CONDITIONS WITH MODERATING TEMPERATURES ARE EXPECTED SUNDAY
NIGHT THROUGH TUESDAY. WEDNESDAY...A MOIST SOUTHERLY FLOW WILL
INCREASE OVER OUR AREA IN ADVANCE OF APPROACHING COLD FRONT FROM THE
WEST. PRECIP WILL DEVELOP BY LATE WEDNESDAY IN RESPOND TO ISENTROPIC
LIFTING OVER THE REGION. SO I HAVE KEPT SLIGHT CHANCE POPS LATE
WED/THU. TEMPERATURES WILL REMAIN 5 -10 DEGREES BELOW NORMALS
SUN/MON BEFORE WARMING UP INTO NORMALS TUESDAY.
&&
.AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
AT KCLT...IFR CONDITIONS CONTINUE AT MID-AFTERNOON. GUIDANCE
CONTINUE TO SUGGEST THAT CIGS WILL GRADUALLY INCREASE INTO THE MVFR
RANGE BY 20Z AND THEN ESSENTIALLY HOLD THERE. AN AREA OF DRIZZLE
ACROSS UPSTATE SC COULD PUT A WRENCH IN THIS THINKING AS VSBYS`S
HAVE CRASHED TO 2 MILES WITHIN IT WITH LIFR CIGS. HOWEVER...WILL BANK ON
IT DISSIPATING AS IT PROGRESSES E. AFTER 00Z...EXPECT A BROKEN LINE
OF THUNDERSTORMS TO APPROACH AND WILL CARRY A PERIOD OF TSRA IN THE
03Z-05Z TIMEFRAME. THE THREAT FOR A SEVERE STORM IS POSSIBLE...BUT
PROB TOO LOW AT THIS POINT TO PUT IN THE TAF. THE CONVECTION WILL
MOVE EAST OF THE AREA BY 06Z...WITH CONDITIONS IMPROVING TO VFR BY
09Z.
ELSEWHERE...PESKY LIFR STILL HANGING IN AT EARLY AFTERNOON. AREA OF
DRIZZLE OVER THE UPSTATE HAS LOWERED CIG/VSBY AT KGSP/KGMU AGAIN.
EXPECT THAT ONCE THIS MOVES EAST SOME RAPID IMPROVEMENT SHOULD
COMMENCE WITH CIGS IMPROVING TO MVFR AND VSBY TO VFR BY 21Z AS
MIXING IMPROVES. AT KAVL...GUIDANCE SUGGESTS THAT CURRENT VFR CONDITIONS
WILL FILL IN WITH MVFR BY 20Z OR SO. AFTER 00Z...A BROKEN LINE OF
THUNDERSTORMS WILL APPROACH FROM THE W-NW AND WILL CARRY A PERIOD OF
THUNDER AT ALL TAF SITES. A SEVERE STORMS ARE POSSIBLE...BUT PROB TOO
LOW TO PUT IN TAFS AT THE MOMENT. ONCE THE FRONT AND ASSOCIATION
CONVECTION MOVES EAST BY 05Z...EXPECT CONDITIONS TO IMPROVE TO VFR.
OUTLOOK...VFR/DRY WEATHER WILL CONTINUE INTO THU NIGHT. HOWEVER...BY
LATE THU NIGHT...MOISTURE WILL INCREASE YET AGAIN AS ANOTHER STORM
SYSTEM APPROACHES THE REGION FROM THE WEST. CHANCES FOR SHOWERS/FLT
RESTRICTIONS WILL PERSIST THROUGH AT LEAST SATURDAY MORNING. DRY
WEATHER SHOULD RETURN BY THE END OF THE WEEKEND.
AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)...
WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...JOH
NEAR TERM...LG
SHORT TERM...PM
LONG TERM...JOH
AVIATION...LG
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
537 AM CST WED FEB 29 2012
.UPDATE...
AVIATION DISCUSSION UPDATED FOR 12Z TAF ISSUANCE BELOW.
ADJUSTED WARNING AREAS...ADDING WESTERN COUNTIES TO THE BLIZZARD
WARNING BASED ON LATEST OBS AND REPORTS FROM HAND COUNTY. ALSO
ADDED IN SOME MIXED PRECIP FOR SOUTHERN TIER COUNTIES FROM SPINK
EASTWARD TO GRANT COUNTY. A SECONDARY BAND OF PRECIP ON THE WARM
CONVEYOR SIDE OF THE STORM IS MAKING ITS WAY NORTH AND BRINGING
FREEZING RAIN...SLEET AND SNOW. LATEST RUC INDICATES THIS MIXED
PRECIP WILL LINGER THROUGH ABOUT 9 OR 10Z. OTHERWISE FROM ABERDEEN
WEST ALL AREAS ARE RECEIVING SNOW. WINDS HAVE SHIFTED AND ARE
INCREASING OUT OF THE NORTHWEST FROM THE MISSOURI RIVER VALLEY
WEST. THIS TREND WILL TRANSLATE EAST OVER THE NEXT 4 TO 5 HOURS.
&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TODAY THROUGH FRIDAY
THE FORECAST CHALLENGES ARE BECOMING FEWER THIS MORNING...AND
MAINLY INCLUDE SNOW ACCUMULATIONS AND WHERE THE EASTERN FRINGE OF
BLIZZARD CONDITIONS END UP SETTING UP TODAY...ALONG WITH
TEMPERATURES AND MINUSCULE PRECIPITATION CHANCES GLANCING THE
NORTHERN TIER COUNTIES THURSDAY AND FRIDAY.
CURRENTLY...A 987HPA SURFACE LOW PRESSURE CENTER IS PUSHING INTO
SOUTHWESTERN MINNESOTA. THE UPPER LOW CIRCULATION CENTER IS NOTED
IN RADAR AND SATELLITE IMAGERY OVER THE VERY NORTHWEST CORNER OF
IOWA AT THIS TIME. UNDER A CLOUDY SKY AND ONGOING MODERATE TO
HEAVY SNOW...TEMPERATURES HAVE BEEN HOLDING IN THE TEENS AND 20S
ACROSS THE MISSOURI RIVER VALLEY...WITH READINGS IN THE UPPER 20S
TO LOWER 30S ACROSS THE JAMES RIVER VALLEY EASTWARD INTO THE RED
RIVER VALLEY. NORTHWEST WIND SPEEDS HAVE ALSO MARKEDLY INCREASED
ACROSS THE MISSOURI RIVER VALLEY EARLY THIS MORNING INTO THE 15 TO
30 MPH RANGE WITH GUSTS UP TO 40 MPH NOTED SO FAR.
WITH THE PRELIMINARY REPORTS OF SNOWFALL AND BLIZZARD CONDITIONS
ACROSS THE WEST LATE LAST EVENING INTO EARLY THIS MORNING...ALONG
WITH REPORTS OF SNOW AND ICE AND SLEET ACCUMULATION ACROSS
PORTIONS OF THE JAMES RIVER VALLEY UP ONTO THE PRAIRIE COTEAU AND
EAST INTO THE RED RIVER VALLEY...HAVE DECIDED TO MAKE ONLY A
COUPLE OF MODEST ADJUSTMENTS THIS MORNING TO THE WINTER STORM
HEADLINES. THE BLIZZARD WARNING WAS EXTENDED INTO
JONES/LYMAN/BUFFALO AND HAND COUNTIES LATE LAST EVENING...AND
SPINK COUNTY HAS BEEN ADDED TO THE BLIZZARD HEADLINE EARLY THIS
MORNING...GIVEN THE REPORTS OF BLIZZARD CONDITIONS OUT WEST AND
THE EXPECTED SPREAD OF BLIZZARD CONDITIONS OVER INTO THE JAMES
RIVER VALLEY TODAY. EAST OF THE JAMES RIVER...THOUGH...WIND SPEEDS
BECOME A BIT MORE MARGINAL FOR BLIZZARD CONDITIONS...SO OPTED TO
REPLACE THE BLIZZARD WARNING OVER MARSHALL/DAY/ROBERTS/BIG
STONE/TRAVERSE COUNTIES WITH A WINTER STORM WARNING HEADLINE.
THESE COUNTIES WILL SEE WINTER STORM WARNING CRITERIA MET /HEAVY
SNOW ACCUMULATIONS AS WELL AS A MIX OF ICE AND SNOW ACCUMULATIONS/
BEFORE THEY SEE BLIZZARD WARNING CRITERIA MET. SO THE CHANGES WERE
MADE WITH THIS MORNING`S PACKAGE.
WELL...LAST NIGHT`S MODEL SOLUTIONS DID A GOOD JOB OF DEPICTING
THE INITIAL WAA-FORCED BROAD DEFORMATION ZONE BAND OF MODERATE TO
HEAVY THAT SET UP ACROSS THE NORTHERN TIER COUNTIES YESTERDAY
AFTERNOON THROUGH EARLY THIS MORNING...ALONG WITH THE FREEZING
RAIN/SLEET THREAT ACROSS THE SOUTHEASTERN THIRD OF FORECAST ZONES
LAST EVENING THROUGH EARLY THIS MORNING...AND THEY DID
SURPRISINGLY WELL TO DENOTE THE STRONG COLD-AIR INSTABILITY
INFLUENCED POTENTIALLY SIGNIFICANT TROWAL-FORCED SECONDARY BAND OF
SNOW ACROSS EAST CENTRAL INTO NORTHEAST SOUTH DAKOTA AND WEST
CENTRAL MINNESOTA. THAT IS WHAT IS ONGOING PER RADAR AND SATELLITE
IMAGERY THIS MORNING. NICE COMMA HEAD NOTED IN SATELLITE IMAGERY
WHERE COLD/DRY TONGUE DRY SLOT INFLUENCED AIR IS WRAPPING BACK
AROUND ON ITSELF AS IT COLLIDES INTO THE WARM CONVEYOR BELT
/TROWAL/ ON THE NORTH AND EAST SIDE OF THIS LOW PRESSURE SYSTEM.
THERE WILL LIKELY CONTINUE TO BE OCCASIONAL PERIODS OF INCH AN
HOUR SNOW RATES THIS MORNING ACROSS THE EASTERN CWA AS THIS TROWAL
BAND OF SNOW BEGINS TO PIVOT AROUND THE UPPER LOW. SEE WSW FOR
SNOW AMOUNT DETAILS.
THIS SYSTEM IS PULLING AWAY FROM THE REGION BY LATE THIS
AFTERNOON...AND CONDITIONS SHOULD BE IMPROVING MARKEDLY THIS
AFTERNOON OUT WEST INTO THIS EVENING OUT EAST. A FEW MORE RATHER
WEAK S/WS RIPPLE EASTWARD THROUGH THE UPPER FLOW THURSDAY INTO
FRIDAY...BUT FRIDAY LOOKS TO BE THE BEST SHOT AT SOME CAA-FORCED
SNOW SHOWERS OR SNOW FLURRIES. NO OTHER NOTEWORTHY CHANGES MADE TO
TEMPERATURES OR WINDS THROUGH THE SHORT TERM.
.LONG TERM...FRIDAY NIGHT THROUGH TUESDAY
MODELS REMAIN IN GOOD AGREEMENT THROUGH THE LONG TERM FORECAST
PERIOD. A MAINLY DRY NORTHWEST FLOW ALOFT IS EXPECTED TO TRANSITION
OVER THE AREA FRIDAY NIGHT AND CONTINUE THROUGH THE WEEKEND. A
FAST MOVING CLIPPER TROUGH IS EXPECTED TO SLIDE SEWD IN THE NW FLOW
THROUGH ERN SD SATURDAY AFTERNOON...BUT WITH MOST ATMOSPHERIC
FORCING REMAINING JUST EAST OF THE AREA...ONLY ANTICIPATING AN INCREASE IN
CLOUDS ALONG WITH A COLD FRONTAL PASSAGE/AIRMASS CHANGE. TRENDED
FORECAST TOWARD THE MORE RUN TO RUN CONSISTENT ECMWF AND GEM
SOLUTIONS. ON SUNDAY...THE NW FLOW ALOFT TRANSLATES EASTWARD AND
H5 HEIGHTS RISE RAPIDLY. THE LOW LEVELS WILL BE SLOW TO RESPOND TO
THE INCREASED HEIGHTS/UPPER LEVEL WARMING SUNDAY BUT AS H5 HEIGHTS
CONTINUE TO RISE MONDAY...LOW LEVELS AND SFC RESPOND IN ERNEST.
TEMPERATURES ARE EXPECTED TO REMAIN BELOW AVERAGE THROUGH
SUNDAY...WARMING TO ABOVE AVERAGE LEVELS FOR MONDAY AND TUESDAY.
&&
.AVIATION...
12Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
MAJOR WINTER STORM SYSTEM CONTINUES EARLY THIS MORNING WITH MVFR/IFR
CONDITIONS AT ALL TERMINALS. EXPECT MAINLY IFR CONDITIONS IN LIGHT
TO MODERATE SNOW TO BE THE RULE UNTIL THE EARLY AFTERNOON AT
KPIR/KMBG AND DURING THE EARLY EVENING HOURS AT KABR/KATY. IFR/MVFR
CIGS ARE ANTICIPATED AT KABR/KATY THROUGH THE LATE EVENING HOURS.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...BLIZZARD WARNING UNTIL 6 PM CST /5 PM MST/ THIS EVENING FOR
BROWN-BUFFALO-CAMPBELL-CORSON-DEWEY-EDMUNDS-FAULK-HAND-
HUGHES-HYDE-JONES-LYMAN-MCPHERSON-POTTER-SPINK-STANLEY-
SULLY-WALWORTH.
WINTER STORM WARNING UNTIL 6 PM CST THIS EVENING FOR CLARK-
CODINGTON-DAY-DEUEL-GRANT-HAMLIN-MARSHALL-ROBERTS.
MN...WINTER STORM WARNING UNTIL 6 PM CST THIS EVENING FOR BIG STONE-
TRAVERSE.
&&
$$
SHORT TERM...DORN
LONG TERM...CHURCH
AVIATION...CHURCH
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
400 AM CST WED FEB 29 2012
.DISCUSSION.../ISSUED AT 359 AM CST/
SURFACE LOW PRESSURE IS CENTERED JUST TO THE SOUTH OF SIOUX FALLS
VERY EARLY THIS MORNING AND CONTINUING TO PUSH TO THE NORTHEAST. DRY
SLOT HAS PUSHED AS FAR NORTH AS THE EASTERN I 90 CORRIDOR...WITH
MIXED PRECIPITATION FALLING TO THE NORTH OF THIS...AND MOST LIKELY
GETTING SOME ICING OVER PORTIONS OF EAST CENTRAL SOUTH DAKOTA INTO
SOUTHWESTERN MINNESOTA WHERE TEMPERATURES ARE HOVERING AROUND
FREEZING. BACK TO THE WEST...LIGHT SNOW IS OCCURRING FROM
NORTHEASTERN SOUTH DAKOTA WRAPPING SOUTHWESTWARD ALL THE WAY BACK
INTO NORTH CENTRAL NEBRASKA IN VICINITY OF DEVELOPING TROWAL...WITH
THIS AREA SLOWLY PROGRESSING EASTWARD AS COLDER AIR FILTERS IN
BEHIND THE LOW. HURON AND MITCHELL HAVE BOTH CHANGED OVER TO SNOW
OVER THE PAST HOUR AND EXPECT THIS EASTWARD TREND TO CONTINUE
THROUGH THE EARLY MORNING HOURS...WITH MOST PLACES CHANGING TO ALL
SNOW BY AROUND 12Z. WILL SEE AN ADDITIONAL 1 TO POSSIBLY 2 INCHES OF
SNOW NORTH OF I 90 TODAY AS THE TROWAL PULLS EAST AND SLOWLY WEAKENS
THROUGH THE DAY...WITH LESSER AMOUNTS TO THE SOUTH. AS
EXPECTED...ALREADY SEEING NORTHWESTERLY WINDS PICK UP ON THE
BACKSIDE OF THE LOW AND WITH THIS TREND ALSO CONTINUING THROUGH THE
DAY WILL HAVE AREAS OF BLOWING SNOW ACROSS OUR WEST AND NORTH INTO
THE AFTERNOON. IN TERMS OF HEADLINES...PRETTY MUCH LEFT THEM AS
IS...THOUGH DID REMOVE HANSON AND HUTCHINSON COUNTIES FROM THE
WINTER WEATHER ADVISORY AS THINKING THAT ANY ADDITIONAL SNOWFALL
WILL BE AN INCH OR LESS IN THAT AREA...THOUGH IN TURN ADDED THEM TO
THE WIND ADVISORY OVER THE SOUTHEASTERN PORTION OF THE CWA. DO THINK
THE WIND ADVISORY IS MARGINAL ALONG THE NORTHERN MOST ROW OF
COUNTIES...ALONG THE I90 CORRIDOR...WHERE 0.5 KM WINDS ARE PROGGED
TO BE IN THE 35 TO 40 KT RANGE. CONFIDENCE IS A LITTLE HIGHER TO THE
SOUTH WITH 0.5 KM WINDS OF 40 TO 45 KTS THROUGH THE MISSOURI RIVER
CORRIDOR INTO NORTHWEST IOWA. ALSO CONSIDERED ALLOWING PORTIONS OF
THE SOUTHWESTERN MINNESOTA WINTER WEATHER ADVISORY TO EXPIRE EARLIER
THAN 18Z AS WE CURRENTLY HAVE IT WITH ADDITIONAL SNOWFALL FORECASTED
TO BE AN INCH OR LESS...BUT WITH MIXED PRECIPITATION AND SOME
PROBABLE ICING THIS MORNING..AND THE POSSIBILITY THAT SOME MIXED
PRECIPITATION COULD BE ONGOING AFTER 12Z...LEFT THE EXPIRATION TIME
AT 18Z. IN REGARD TO HIGH TEMPERATURES TODAY...WITH 925 MB TEMPS OF
-2 TO -4 C ACROSS THE AREA WILL SEE HIGHS IN THE LOWER TO MID 30S.
WINDS WILL DROP OFF BY LATE THIS EVENING AS THE LOW PULLS AWAY AND
THE GRADIENT RELAXES. WITH DECREASING CLOUDS LOWS WILL FALL INTO THE
MID AND UPPER TEENS ACROSS MUCH OF THE AREA...EXCEPT LOWER 20S ALONG
THE MISSOURI RIVER CORRIDOR. MAY SEE TEMPERATURES RISE A BIT IN OUR
WEST LATER AT NIGHT AS SOUTHERLY WINDS PICK UP IN ADVANCE OF AN
APPROACHING SURFACE TROUGH TO THE WEST.
THIS BOUNDARY WILL PUSH ACROSS THE REGION ON THURSDAY AS A MIDLEVEL
SHORTWAVE LIFTS UP OVER OUR EAST. IN SPITE OF THAT...LEFT IT DRY
WITH LOW LEVEL MOISTURE PRETTY SPARSE. WILL BE WARMER ON THURSDAY
WITH WARM AIR ADVECTION IN A SOUTHERLY FLOW OUT AHEAD OF THE
TROUGH...WITH HIGHS CLIMBING INTO THE MID 30S NORTH...TO MID 40S
THROUGH THE SIOUX CITY TO STORM LAKE CORRIDOR. COLDER AIR WILL
FILTER IN BEHIND THIS SYSTEM...LEADING TO A COOLER DAY ON FRIDAY
WITH HIGHS MAINLY IN THE 30S. THREW IN SOME FLURRIES ACROSS OUR
NORTHEAST ON FRIDAY NIGHT WITH MODELS HINTING AT IT AS A SHORTWAVE
DROPS SOUTHWARD ON A NORTHWESTERLY UPPER LEVEL FLOW DURING THAT TIME
FRAME.
NOT MUCH FOCUS PUT INTO THE EXTENDED WITH SHORT TERM ISSUES...BUT
MODELS POINTING TOWARD A BUILDING UPPER LEVEL RIDGE OVER OUR AREA
FOR THE WEEKEND INTO THE BEGINNING OF NEXT WEEK. WITH THAT...WILL
REMAIN PRIMARILY DRY WITH A SLOW WARMING TREND THROUGH THE PERIOD.
CONSENSUS NUMBERS WOULD HAVE US INTO THE 40S AND 50S FOR HIGHS BY
MONDAY AND TUESDAY.
&&
.AVIATION.../FOR THE 06Z TAFS/
PRECIP TYPE AND THUNDERSTORMS ARE THE NEAR-TERM CHALLENGES THIS
TAF PERIOD. ELEVATED INSTABILITY AXIS HAD SHIFTED EAST OF THE
INTERSTATE 29 CORRIDOR FROM KFSD TO KSUX BY 05Z. EMBEDDED
THUNDERSTORM POTENTIAL WILL HAVE SUBSIDED FOR THE MOST PART BY
06Z...WHEN THE INSTABILITY WANES NOTABLY. AS FAR AS PRECIPITATION
TYPES GO...HAVE LEANED TOWARD THE RUC AND SREF WHICH DEPICT
SLIGHTLY SLOWER TRANSITIONS TO ALL SNOW FOR KFSD AND KSUX /10Z-
12Z/. WINDS WILL ALSO SHIFT TO THE NORTH/NORTHWEST AROUND THE TIME
THE CHANGEOVER TO SNOW OCCURS...AFTER WHICH SUSTAINED SPEEDS OF 30
MPH WITH GUSTS TO 40 MPH WILL BECOME COMMON...AND PERSIST THROUGH
WEDNESDAY. COULD EVEN SEE PEAK GUSTS TO AROUND 45 MPH ON
WEDNESDAY. VSBY REDUCTIONS WITH THE WIND AND SNOW WILL THEREFORE
BE A CONCERN AS WELL...BUT GENERALLY THINK 1-2SM WILL BE
APPROPRIATE. AS FAR AS CIGS ARE CONCERNED...EXPECTED THE IFR DECK
TO PREVAIL THROUGH WEDNESDAY...ALTHOUGH IMPROVEMENT TO OVC015
/MVFR/ IS POSSIBLE DURING THE AFTERNOON. WINDS BEGIN TO SUBSIDE
AROUND/AFTER 00Z THURSDAY...WITH SCATTERING OF THE LOW CLOUDS
BETWEEN 06Z AND 12Z THURSDAY.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
IA...WIND ADVISORY UNTIL 6 PM CST THIS EVENING FOR IAZ001>003-012>014-
020>022-031-032.
MN...WIND ADVISORY UNTIL 6 PM CST THIS EVENING FOR MNZ089-090-098.
WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR MNZ071-072-080-
081-097.
NE...WIND ADVISORY UNTIL 6 PM CST THIS EVENING FOR NEZ013-014.
SD...WIND ADVISORY UNTIL 6 PM CST THIS EVENING FOR SDZ060>062-065>071.
WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR SDZ040-050-
055>059-063-064.
WINTER STORM WARNING UNTIL NOON CST TODAY FOR SDZ038-039-052>054.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
1141 PM CST TUE FEB 28 2012
.UPDATE...
ADJUSTED WARNING AREAS...ADDING WESTERN COUNTIES TO THE BLIZZARD
WARNING BASED ON LATEST OBS AND REPORTS FROM HAND COUNTY. ALSO ADDED IN
SOME MIXED PRECIP FOR SOUTHERN TIER COUNTIES FROM SPINK EASTWARD
TO GRANT COUNTY. A SECONDARY BAND OF PRECIP ON THE WARM CONVEYOR
SIDE OF THE STORM IS MAKING ITS WAY NORTH AND BRINGING FREEZING
RAIN...SLEET AND SNOW. LATEST RUC INDICATES THIS MIXED PRECIP WILL
LINGER THROUGH ABOUT 9 OR 10Z. OTHERWISE FROM ABERDEEN WEST ALL AREAS
ARE RECEIVING SNOW. WINDS HAVE SHIFTED AND ARE INCREASING OUT OF
THE NORTHWEST FROM THE MISSOURI RIVER VALLEY WEST. THIS TREND WILL
TRANSLATE EAST OVER THE NEXT 4 TO 5 HOURS.
SEE UPDATED AVIATION DISCUSSION BELOW.
&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TONIGHT THROUGH WEDNESDAY
STRONG SURFACE LOW PRESSURE AREA IN SOUTHWEST NEBRASKA MAKING ITS
MOVE LATE THIS AFTERNOON. GOOD AGREEMENT WITH THE MODELS NOW WITH
TAKING THIS SURFACE LOW PRESSURE AREA INTO SOUTHWEST MINNESOTA BY
WEDNESDAY MORNING AND INTENSIFYING IT. RADARS ACROSS THE REGION
NOW SHOWING INCREASING ECHOES AND COVERAGE WITH THE INTENSE LIFT
IN ASSOCIATION WITH THE UPPER AND SURFACE LOW PRESSURE AREAS. HAD
REPORTS OF SNOW...RAIN AND FREEZING RAIN THIS AFTERNOON. THINK ALL
OF THE PRECIPITATION WILL CHANGE OVER TO ALL SNOW THROUGH THE
EVENING HOURS AND AFTER MIDNIGHT ACROSS NORTHEAST SD AND WEST
CENTRAL MN. EXPECT WIDESPREAD SNOW AND BLOWING SNOW OVERNIGHT AND
THROUGH MUCH OF THE DAY WEDNESDAY. WINDS ARE EXPECTED TO BECOME
ALL NORTH THROUGH THE NIGHT AND INCREASE TO 25 TO 35 MPH WITH
WIDESPREAD BLIZZARD CONDITIONS EXPECTED. LEFT ALL WARNINGS AS IS
THROUGH WEDNESDAY AFTERNOON.
.LONG TERM...WEDNESDAY NIGHT THROUGH TUESDAY
EARLY WEDNESDAY NIGHT SFC LOW IS CONTINUING TO MOVE EAST THROUGH
WISCONSIN WITH STILL A SMALL CHANCE FOR LIGHT SNOW ACROSS THE FAR
EASTERN CWA. THROUGH THE OVERNIGHT HOURS SFC LOW WILL CONTINUE
MOVING EASTWARD TOWARDS THE GREAT LAKES AND WILL BRING AN END TO
THE SNOW CHANCES. WEAK SHORTWAVE TRACKS THROUGH THE DAKOTAS ON
THURSDAY WITH MAJORITY OF SNOWFALL REMAINING ACROSS ND. WILL KEEP
SMALL CHANCES ACROSS NORTHERN SD AS SOUTHERN EDGE OF SYSTEM LOOKS
TO AFFECT THIS AREA...BUT ANY AMOUNTS LOOK TO BE RATHER LIGHT.
ANOTHER SHORTWAVE MOVES THROUGH FRIDAY AND FRIDAY NIGHT AND WILL
LEAVE SMALL POPS IN FOR THIS AS WELL. DRY CONDITIONS AT THIS TIME
FOR THE WEEKEND INTO EARLY NEXT WEEK.
&&
.AVIATION...
00Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
AREAS SOUTH AND EAST OF KABR ARE CURRENTLY BEING IMPACTED BY A
SECONDARY CONVECTIVE BAND OF PRECIP ON THE WARM CONVEYOR SIDE OF
THE STORM SYSTEM. THIS IS PRODUCING A MIX OF FREEZING RAIN...SLEET
AND SNOW AT KABR AND IS LIKELY TO CONTINUE UNTIL AROUN 09 OR 10Z.
EAST WINDS IN THIS BELT ARE VERY GUSTY AT 25 TO 35 KTS. KMBG/KPIR
WINDS HAVE SHIFTED TO THE NORTHWEST AND ARE GUSTING TO AROUND 30
KTS CREATING LIFR CONDITIONS IN SNOW AND BLOWING SNOW. THESE WINDS
WILL TRANSLATE EASTWARD TONIGHT. EXPECT ALL SITES TO BE IFR UNTIL AROUND
18Z IN THE WEST AND 21Z IN THE EAST.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...BLIZZARD WARNING UNTIL 6 PM CST /5 PM MST/ WEDNESDAY FOR BROWN-
CAMPBELL-CORSON-DAY-DEWEY-EDMUNDS-FAULK-HUGHES-HYDE-
MARSHALL-MCPHERSON-POTTER-ROBERTS-STANLEY-SULLY-WALWORTH.
WINTER STORM WARNING UNTIL 6 PM CST WEDNESDAY FOR BUFFALO-CLARK-
CODINGTON-DEUEL-GRANT-HAMLIN-HAND-JONES-LYMAN-SPINK.
MN...BLIZZARD WARNING UNTIL 6 PM CST WEDNESDAY FOR BIG STONE-TRAVERSE.
&&
$$
UPDATE...WISE
SHORT TERM...TMT
LONG TERM...MOHR
AVIATION...WISE
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
1102 PM CST TUE FEB 28 2012
.DISCUSSION.../ISSUED AT 925 PM CST/
TEMPERATURES AND PRECIPITATION TYPE CONTINUE TO BE THE MAIN FOCUS
THIS EVENING...WITH THE VAST MAJORITY OF THE CWA WITHIN A FEW
DEGREES OF FREEZING. THE INITIAL WARM FRONTAL BAND OF MOISTURE WHICH
PRODUCED HEAVY RAINFALL REGIONWIDE HAS EXITED TO THE NORTH AND WAS
REPLACED BY LINGERING LIGHT RAIN SHOWERS AND DRIZZLE. WITH
TEMPERATURES NEAR FREEZING...ICING OF VEGETATION AND UNTREATED
SURFACES WAS COMMON...ESPECIALLY TO THE NORTH OF I90. THE NEXT
CONVECTIVE BAND OF SHOWERS WITH EMBEDDED THUNDERSTORMS HAS LIFTED
NORTHWARD FROM NEBRASKA AND IS TRACKING NORTHEAST INTO THE I29
CORRIDOR. EXPECT THESE THUNDERSTORMS TO CONTINUE INTO NW IA AND SW
MINNESOTA OVER THE NEXT SEVERAL HOURS. HEAVY RAINFALL AND PEA SIZED
HAIL WILL BE ASSOCIATED WITH THIS BAND...WHICH HAS CAUSED A FEW
REPORTS OF DAMAGE TO ICE COVERED TREE BRANCHES. LATEST SHORT RANGE
MODELS ARE POINTING TOWARDS A SLIGHTLY SLOWER ARRIVAL OF THE COLDER
AIR AND RESULTANT CHANGE OVER TO SNOW...IN PARTICULAR INTO THE I29
CORRIDOR...SO HAVE BACKED OFF ON THAT TIMING BY AROUND 2 OR 3 HOURS.
ADDITIONALLY...THINK THAT VERY LITTLE ADDITIONAL WARMING WILL OCCUR
THROUGH MIDNIGHT...SO HAVE ADJUSTED TEMPERATURES THIS EVENING TO
REMAIN FAIRLY STEADY STATE. ALSO SLOWED THE EASTWARD PROGRESSION OF
THE SUB FREEZING TEMPERATURES. EVEN WITH THESE CHANGES...HEADLINES
LOOK IN PRETTY GOOD SHAPE.
&&
.AVIATION.../FOR THE 06Z TAFS/
PRECIP TYPE AND THUNDERSTORMS ARE THE NEAR-TERM CHALLENGES THIS
TAF PERIOD. ELEVATED INSTABILITY AXIS HAD SHIFTED EAST OF THE
INTERSTATE 29 CORRIDOR FROM KFSD TO KSUX BY 05Z. EMBEDDED
THUNDERSTORM POTENTIAL WILL HAVE SUBSIDED FOR THE MOST PART BY
06Z...WHEN THE INSTABILITY WANES NOTABLY. AS FAR AS PRECIPITATION
TYPES GO...HAVE LEANED TOWARD THE RUC AND SREF WHICH DEPICT
SLIGHTLY SLOWER TRANSITIONS TO ALL SNOW FOR KFSD AND KSUX /10Z-
12Z/. WINDS WILL ALSO SHIFT TO THE NORTH/NORTHWEST AROUND THE TIME
THE CHANGEOVER TO SNOW OCCURS...AFTER WHICH SUSTAINED SPEEDS OF 30
MPH WITH GUSTS TO 40 MPH WILL BECOME COMMON...AND PERSIST THROUGH
WEDNESDAY. COULD EVEN SEE PEAK GUSTS TO AROUND 45 MPH ON
WEDNESDAY. VSBY REDUCTIONS WITH THE WIND AND SNOW WILL THEREFORE
BE A CONCERN AS WELL...BUT GENERALLY THINK 1-2SM WILL BE
APPROPRIATE. AS FAR AS CIGS ARE CONCERNED...EXPECTED THE IFR DECK
TO PREVAIL THROUGH WEDNESDAY...ALTHOUGH IMPROVEMENT TO OVC015
/MVFR/ IS POSSIBLE DURING THE AFTERNOON. WINDS BEGIN TO SUBSIDE
AROUND/AFTER 00Z THURSDAY...WITH SCATTERING OF THE LOW CLOUDS
BETWEEN 06Z AND 12Z THURSDAY.
&&
.PREV DISCUSSION.../ISSUED AT 300 PM CST/
MADE VERY FEW CHANGES TO THE EXISTING HEADLINES...OTHER THAN ADDING
IN A WIND ADVISORY FOR MUCH OF THE AREA WEDNESDAY. TEMPERATURES
HOVERING RIGHT AROUND THE FREEZING MARK IS CAUSING SOME FREEZING OF
EXPOSED SURFACES AND SIDEWALKS BUT THE ROADS SO FAR HAVE REMAINED
ONLY SPOTTY ICY. FAIRLY HIGH RAIN RATES WILL CONTINUE INTO THE
EVENING WITH CONVECTION EXPECTED ALONG THE FAR SOUTHERN CWA THROUGH
ABOUT 4Z SO EXPECT THIS WILL AID IN HIGH...AROUND 0.10 INCH PER HOUR
RAIN RATES THROUGH THIS TIME. TEMPERATURES WILL REMAIN STEADY OR
SLOWLY RISE THROUGH THE EARLY PART OF THE NIGHT...THEN FALL AS THE
FRONT PASSES LATER TONIGHT AND COLDER AIR WRAPS IN. THIS IS ALSO
WHEN THE BEST CHANCE FOR SNOW IS AND STILL THINKING ABOUT 4 INCHES
WITHIN THE WARNING AREA THROUGH OUR NW ZONES. IN ADDITION...PRETTY
STRONG WINDS ARE STILL LIKELY...ADMITTEDLY ONLY A MARGINAL WARNING
BUT CLOSE ENOUGH NOT TO SWITCH TO AN ADVISORY. WINDY AND MIXY ON
WEDNESDAY WITH AREAS OF BLOWING SNOW IN THE NORTHERN PART OF THE
CWA. TEMPERATURES SHOULD WARM INTO MAINLY THE LOWER TO MIDDLE 30S.
EXPECT NORTHWEST WINDS BEHIND THIS VERY STRONG LOW OF ABOUT 30 TO 40
MPH THROUGH THE DAY. /08
FURTHER OUT...REALLY NOT A LOT HAPPENING AT THIS POINT. SURFACE
RIDGE BEGINS TO SHIFT EASTWARD THROUGH THE NIGHT ON WEDNESDAY
NIGHT...WHICH MAY STEADY OUT OUR TEMPERATURES AS THE NIGHT
PROGRESSES. THIS IS FOLLOWED BY A DECENT WAVE PASSING BY ON THURSDAY
NOTED BY THE UPPER QG FORCING AND PV. THIS SHORT WAVE IS ON THE
SOUTHEAST SIDE OF A CLOSED LOW IN SOUTHERN SASKATCHEWAN AND LIFTS
NORTHEASTWARD THROUGH THIS AREA. THIS FAR SOUTH IN OUR FORECAST
AREA...MEASURABLE PRECIPITATION WILL VERY LIKELY BE HARD TO FIND DUE
TO DRY AIR BELOW 700MB. THEREFORE OPTED TO GO DRY...BUT WOULD NOT BE
SURPRISED IF A FEW FLURRIES FELL THROUGHOUT OUR NORTHERN ZONES ON
THURSDAY...JUST NOT ENOUGH TO WORRY ABOUT RIGHT NOW. HIGHS ON
THURSDAY WILL BE MILD IN OUR FAR SOUTHERN ZONES...WELL INTO THE
40S...WHERE THICKER CLOUD COVER WILL BE THE LEAST PREVALENT. BUT
ALONG AND NORTH OF I90...CLOUDS WILL LIKELY HOLD TEMPERATURES IN THE
30S.
ON THURSDAY NIGHT AND FRIDAY...ALL MODELS POINT TO THE
AFOREMENTIONED CLOSED UPPER LOW MOVING INTO THE NORTHERN TIER OF THE
U.S. WITH VARYING DEGREES OF TIMING AND STRENGTH. THE NEXT WAVE ALSO
TRAVELS NORTHEASTWARD ON THE SOUTH SIDE OF THE UPPER LOW...BUT NOW
APPEARS TO BE AFFECTING AREAS TO THE SOUTH OF OUR FORECAST AREA. THE
MODELS HAVE BEEN TRENDING TOWARD A MORE SOUTHERLY SOLUTION WITH THIS
FEATURE FOR SEVERAL RUNS NOW...SO DECIDED TO ELIMINATE POPS FOR OUR
SOUTHERN ZONES. BECAUSE OF THE LACK OF PRECIPITATION NOW EXPECTED...
THE SIOUX CITY AND STORM LAKE AREAS MAY WARM TO NEAR 40 NOW...
COOLING OFF HEADING NORTHWARD TO AROUND 30 IN OUR NORTHERN ZONES.
NOT A LOT GOING ON IN THE EXTENDED. THE UPPER LOW MOVES EASTWARD
INTO SOUTHEAST CANADA THROUGH THE WEEKEND WHICH WILL BE FOLLOWED BY
RIDGING THROUGHOUT THE WESTERN U.S.. THIS WILL BE HIGHLIGHTED BY A
WARMUP ACROSS OUR AREA EARLY NEXT WEEK ONCE THE CHILLY SURFACE HIGH
EXITS EASTWARD. RIGHT NOW...THE EXTENDED LOOKS DRY. /MJF
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
IA...WIND ADVISORY FROM 4 AM TO 6 PM CST WEDNESDAY FOR IAZ001>003-
012>014-020>022-031-032.
MN...WINTER WEATHER ADVISORY UNTIL NOON CST WEDNESDAY FOR MNZ071-072-
080-081-097.
WIND ADVISORY FROM 4 AM TO 6 PM CST WEDNESDAY FOR MNZ089-090-098.
NE...WIND ADVISORY FROM 4 AM TO 6 PM CST WEDNESDAY FOR NEZ013-014.
SD...WINTER WEATHER ADVISORY UNTIL NOON CST WEDNESDAY FOR SDZ040-050-
055>060-063>065.
WIND ADVISORY FROM 4 AM TO 6 PM CST WEDNESDAY FOR SDZ061-062-
066>071.
WINTER STORM WARNING UNTIL NOON CST WEDNESDAY FOR SDZ038-039-
052>054.
&&
$$
FOR FREQUENTLY ASKED QUESTIONS ABOUT THE AREA FORECAST DISCUSSION
VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY/GENERAL/AFD_FAQS.PHP (ALL LOWER CASE)
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
350 PM EST WED FEB 29 2012
.SYNOPSIS...
A STRONG COLD FRONT WILL IMPACT THE REGION THROUGH TONIGHT AND
REACH THE EAST COAST BY LATE THURSDAY. ANOTHER LOW WILL APPROACH
FROM THE CENTRAL AND SOUTHERN PLAINS ON FRIDAY AND SATURDAY.
&&
.NEAR TERM /THROUGH THURSDAY/...
AS OF 348 PM EST WEDNESDAY...
UPDATED ISC GRIDS AND ZONE TO INCLUDE TORNADO WATCH 52 IN EFFECT
UNTIL 10 PM.
AS OF 320 PM EST WEDNESDAY...
THE WARM FRONT WILL SLOWLY LIFT NORTH THIS EVENING INTO
TONIGHT... AS A COLD FRONT ADVANCES EAST ACROSS THE REGION. THE
ATMOSPHERE IS BEING MORE UNSTABLE ACROSS OUR REGION...WITH THIN OF
CLOUDS/BREAKS ACROSS THE WESTERN MOUNTAINS. THE 7H-5H LAPS RATES
ON THE 19Z SPC MESOSCALE ANALYSIS ARE 7 TO 7.5 ACROSS THE WESTERN
MOUNTAINS. LOW LEVEL WINDS INCREASE TONIGHT AND WITH THE HIGH
SHEAR ENVIRONMENT...ANY BAND OF THUNDERSTORMS MAY PRODUCE STRONG
GUSTY WINDS AND HAIL.
NAM/SREF...WRFARW-RNK AND EVEN THE GFS WERE SHOWING AREAS OF SHOWERS
AND THUNDERSTORMS ALONG AND AHEAD OF THE COLD FRONT THAT IS FORECAST
TO COME THROUGH THE COUNTY WARNING AREA BY MIDNIGHT TONIGHT. EXPECT
THE MOST INTENSE STORMS AND THE THREAT OF HEAVIEST RAINFALL TO OCCUR
BETWEEN 21Z/4PM AND 03Z/10PM. WITH LOWER FFG CONSIDERED A FLOOD
WATCH FOR SOUTHEAST WEST VIRGINIA...BUT WITH FAST MOVING LINE
FLOODING MAY BE MORE LOCALIZED. WILL HAVE TO MONITOR AS AFTERNOON
PROGRESSES. COLDER AIR COMES IN TONIGHT BEHIND THE COLD FRONT.
USED A BLEND OF THE HRRR AND NAM FOR TEMPERATURES TONIGHT. LOWS WILL
RANGE FROM THE UPPER 30S IN THE NORTHWEST TO THE MID 50S IN THE
SOUTHEAST.
LOOKING AHEAD TO THURSDAY MORNING...THE COLD FRONT WILL BE WELL EAST
OF OUR AREA BY SUNRISE...AND BELIEVE ONLY ISOLATED SHOWERS...IF
ANY...WILL BE ALL THAT REMAIN ACROSS THE PIEDMONT AS HIGH PRESSURE
BUILDS IN FROM THE WEST. HIGH PRESSURE BUILD ACROSS THE MOUNTAINS
BY THURSDAY AFTERNOON. UNDER PLENTY OF SUNSHINE...HIGHS THURSDAY WILL
RANGE FROM THE MID 50S IN THE MOUNTAINS TO THE MID 70S IN THE
SOUTHEAST.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
AS OF 300 PM EST WEDNESDAY...
HIGH PRESSURE MOVES OVERHEAD THU EVENING THEN EAST TO THE COAST
FRIDAY MORNING. THIS SHOULD BE A PATTERN CONDUCIVE FOR COOLER
VALLEY/PIEDMONT TEMPS WITH SOME WARMING AFTER MIDNIGHT...TOWARD DAWN
WESTERN RIDGES PER INCREASING SE/S FLOW.
MODELS ARE SHOWING AGREEMENT OVERALL IN BRINGING INCREASING MOISTURE
AHEAD OF THE NEXT SYSTEM RAPIDLY NORTHWARD INTO OUR AREA FRIDAY
MORNING...AND WITH RETREATING HIGH...MAY SEE A IN-SITU WEDGE SET
UP...SO LOWERED HIGHS SOME FROM MOS FRIDAY IN THE TYPICAL WEDGE
AREAS. WILL SEE RAIN CHANCES INCREASE FROM SW TO NE BY AFTN WITH
FLOW BECOMING SOUTHERLY. DIFFERENCES DO COME INTO PLAY ON BREAKDOWN
OF THE WEDGE WITH GFS SLOWEST AND NAM FASTEST. ATTM...LEANED TOWARD
A GFS/ECMWF SOLUTION AS THE NAM SEEMS TOO FAST GIVEN POTENTIAL WAVE
FORMING ALONG THE WARM FRONT OFF THE NC COAST FRIDAY AFTN.
MODELS ARE TRYING TO SHOW A LULL BETWEEN THE WARM FRONTAL/WAA PRECIP
FRIDAY AFTN AND THE COLD FRONT PRECIP FRI NIGHT-SAT MORNING. FOR NOW
WILL GO WITH THAT LULL TO BE FRIDAY EVENING BASED ON MODEL/HPC
CONSENSUS BUT STILL WITH MOISTURE STREAMING RAPIDLY NE AHEAD OF THE
COLD FRONT WILL KEEP POPS IN THE CHANCE RANGE...THEN BUMP IT TO
CATEGORICAL IN THE WEST OVERNIGHT FRIDAY AND SWINGING THE FRONT
ACROSS BY SAT AFTN...DRYING FROM WEST TO EAST. THIS WILL BE ANOTHER
ACTIVE FRONT WITH THUNDERSTORMS AND HEAVIER RAINS POSSIBLE.
ATTM...SPC HAS A SLIGHT RISK TO OUR WEST FRI NIGHT AND TIMING OF
THIS LINE AT NIGHT MAY INHIBIT SVR THREAT....ALTHOUGH QLCS LOOKS
LIKE A GOOD BET WITH 50-60 KNOT LOW LVL JET AND POTENTIAL FOR SOME
SPINUPS GIVEN THE GFS FORECAST AND DIRECTIONAL SHEAR AROUND 12Z SAT.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 308 PM EST WEDNESDAY...
SATURDAY EVENING THE BACK EDGE OF AN AREA OF PRECIPITATION
ASSOCIATED WITH SATURDAYS COLD FRONTAL PASSAGE WILL BE EXITING
SOUTHSIDE VIRGINIA...AND NEIGHBORING SECTIONS OF NORTH CAROLINA.
NORTHWEST FLOW BEHIND THE FRONT WILL HELP GENERATE SOME UPSLOPE
RAIN/SNOW SHOWERS ACROSS PARTS OF SE WV...THAT WILL ISOLATED IN
COVERAGE AND LAST THROUGH EARLY SUNDAY MORNING.
SUNDAY THROUGH MONDAY...OUR NEXT NORTHERN STREAM CLIPPER SYSTEM WILL
RACE THROUGH THE OHIO VALLEY AND THEN THE CENTRAL APPALACHIANS.
PRECIPITATION IS EXPECTED TO START AS RAIN SHOWERS ACROSS SE WV ON
SUNDAY AFTERNOON. DURING THE OVERNIGHT HOURS...LOOK FOR COVERAGE TO
SPREAD FARTHER EAST AND BECOME A MIX OF RAIN AND SNOW...THE THE BULK
OF THE SNOW CONFINED TO SE WV...NEIGHBORING COUNTIES OF SW VA...AND
THE NORTHERN MOUNTAINS OF NC. NORTHWEST FLOW ON THE BACK SIDE OF THE
SYSTEM WILL ALLOW FOR A CONTINUATION OF UPSLOPE RAIN/SNOW SHOWERS
ACROSS THE MOUNTAINS ON MONDAY THAT WILL TREND TO ISOLATE RAIN
SHOWERS BY THE AFTERNOON.
TUESDAY INTO WEDNESDAY...HIGH PRESSURE WILL BUILD OVER AND THEN EAST
OF THE REGION. THIS WILL ALLOW FOR AN END OF THE PRECIPITATION...AND
TREND TOWARDS MILDER CONDITIONS BY WEDNESDAY WITH SOUTHERLY FLOW
ESTABLISHING ITSELF. CLOUD COVER WILL ALSO INCREASE ON WEDNESDAY AS
LOW LEVEL FLOW GAINS A FETCH OF THE ATLANTIC AND MOISTURE IS
ADVECTED UPSLOPE ALONG THE CREST OF THE BLUE RIDGE.
&&
.AVIATION /21Z WEDNESDAY THROUGH MONDAY/...
AS OF 1120 AM EST WEDNESDAY...
MVFR EXPECTED WITH POCKETS OF IFR/LIFR THIS AFTERNOON IN CLOUDS
AND CONVECTION. SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE
THIS AFTERNOON INTO TONIGHT. THE COLD FRONT WILL APPROACH BLF AND
LWB THIS EVENING AND SHOULD BE EAST OF LYH AND DAN BY 09Z. A BKN
LINE OF SHOWERS AND THUNDERSTORMS LIKELY TO ACCOMPANY THE FRONTAL
PASSAGE...WITH TEMPORARY IFR TO MVFR CONDITIONS. FOLLOWING THE
COLD FRONT EXPECT A RETURN TO VFR WEATHER FOR LATE TONIGHT INTO
THURSDAY.
ANOTHER WARM FRONT WILL AFFECT THE REGION FRIDAY...WITH POSSIBLE
MVFR CIGS. A STRONG COLD FRONT SHOULD ARRIVE IN THE LATE FRIDAY
NIGHT-SAT TIME FRAME RESULTING IN WIDESPREAD MVFR/IFR DUE TO
SHOWERS AND THUNDERSTORMS.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS/KK
SHORT TERM...WP
LONG TERM...DS
AVIATION...AMS/KK/PM
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
327 PM EST WED FEB 29 2012
.SYNOPSIS...
A STRONG COLD FRONT WILL IMPACT THE REGION THROUGH TONIGHT AND
REACH THE EAST COAST BY LATE THURSDAY. ANOTHER LOW WILL APPROACH
FROM THE CENTRAL AND SOUTHERN PLAINS ON FRIDAY AND SATURDAY.
&&
.NEAR TERM /THROUGH THURSDAY/...
AS OF 320 PM EST WEDNESDAY...
THE WARM FRONT WILL SLOWLY LIFT NORTH THIS EVENING INTO
TONIGHT... AS A COLD FRONT ADVANCES EAST ACROSS THE REGION. THE
ATMOSPHERE IS BEING MORE UNSTABLE ACROSS OUR REGION...WITH THIN OF
CLOUDS/BREAKS ACROSS THE WESTERN MOUNTAINS. THE 7H-5H LAPS RATES
ON THE 19Z SPC MESOSCALE ANALYSIS ARE 7 TO 7.5 ACROSS THE WESTERN
MOUNTAINS. LOW LEVEL WINDS INCREASE TONIGHT AND WITH THE HIGH
SHEAR ENVIRONMENT...ANY BAND OF THUNDERSTORMS MAY PRODUCE STRONG
GUSTY WINDS AND HAIL.
NAM/SREF...WRFARW-RNK AND EVEN THE GFS WERE SHOWING AREAS OF SHOWERS
AND THUNDERSTORMS ALONG AND AHEAD OF THE COLD FRONT THAT IS FORECAST
TO COME THROUGH THE COUNTY WARNING AREA BY MIDNIGHT TONIGHT. EXPECT
THE MOST INTENSE STORMS AND THE THREAT OF HEAVIEST RAINFALL TO OCCUR
BETWEEN 21Z/4PM AND 03Z/10PM. WITH LOWER FFG CONSIDERED A FLOOD
WATCH FOR SOUTHEAST WEST VIRGINIA...BUT WITH FAST MOVING LINE
FLOODING MAY BE MORE LOCALIZED. WILL HAVE TO MONITOR AS AFTERNOON
PROGRESSES. COLDER AIR COMES IN TONIGHT BEHIND THE COLD FRONT.
USED A BLEND OF THE HRRR AND NAM FOR TEMPERATURES TONIGHT. LOWS WILL
RANGE FROM THE UPPER 30S IN THE NORTHWEST TO THE MID 50S IN THE
SOUTHEAST.
LOOKING AHEAD TO THURSDAY MORNING...THE COLD FRONT WILL BE WELL EAST
OF OUR AREA BY SUNRISE...AND BELIEVE ONLY ISOLATED SHOWERS...IF
ANY...WILL BE ALL THAT REMAIN ACROSS THE PIEDMONT AS HIGH PRESSURE
BUILDS IN FROM THE WEST. HIGH PRESSURE BUILD ACROSS THE MOUNTAINS
BY THURSDAY AFTERNOON. UNDER PLENTY OF SUNSHINE...HIGHS THURSDAY WILL
RANGE FROM THE MID 50S IN THE MOUNTAINS TO THE MID 70S IN THE
SOUTHEAST.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
AS OF 300 PM EST WEDNESDAY...
HIGH PRESSURE MOVES OVERHEAD THU EVENING THEN EAST TO THE COAST
FRIDAY MORNING. THIS SHOULD BE A PATTERN CONDUCIVE FOR COOLER
VALLEY/PIEDMONT TEMPS WITH SOME WARMING AFTER MIDNIGHT...TOWARD DAWN
WESTERN RIDGES PER INCREASING SE/S FLOW.
MODELS ARE SHOWING AGREEMENT OVERALL IN BRINGING INCREASING MOISTURE
AHEAD OF THE NEXT SYSTEM RAPIDLY NORTHWARD INTO OUR AREA FRIDAY
MORNING...AND WITH RETREATING HIGH...MAY SEE A IN-SITU WEDGE SET
UP...SO LOWERED HIGHS SOME FROM MOS FRIDAY IN THE TYPICAL WEDGE
AREAS. WILL SEE RAIN CHANCES INCREASE FROM SW TO NE BY AFTN WITH
FLOW BECOMING SOUTHERLY. DIFFERENCES DO COME INTO PLAY ON BREAKDOWN
OF THE WEDGE WITH GFS SLOWEST AND NAM FASTEST. ATTM...LEANED TOWARD
A GFS/ECMWF SOLUTION AS THE NAM SEEMS TOO FAST GIVEN POTENTIAL WAVE
FORMING ALONG THE WARM FRONT OFF THE NC COAST FRIDAY AFTN.
MODELS ARE TRYING TO SHOW A LULL BETWEEN THE WARM FRONTAL/WAA PRECIP
FRIDAY AFTN AND THE COLD FRONT PRECIP FRI NIGHT-SAT MORNING. FOR NOW
WILL GO WITH THAT LULL TO BE FRIDAY EVENING BASED ON MODEL/HPC
CONSENSUS BUT STILL WITH MOISTURE STREAMING RAPIDLY NE AHEAD OF THE
COLD FRONT WILL KEEP POPS IN THE CHANCE RANGE...THEN BUMP IT TO
CATEGORICAL IN THE WEST OVERNIGHT FRIDAY AND SWINGING THE FRONT
ACROSS BY SAT AFTN...DRYING FROM WEST TO EAST. THIS WILL BE ANOTHER
ACTIVE FRONT WITH THUNDERSTORMS AND HEAVIER RAINS POSSIBLE.
ATTM...SPC HAS A SLIGHT RISK TO OUR WEST FRI NIGHT AND TIMING OF
THIS LINE AT NIGHT MAY INHIBIT SVR THREAT....ALTHOUGH QLCS LOOKS
LIKE A GOOD BET WITH 50-60 KNOT LOW LVL JET AND POTENTIAL FOR SOME
SPINUPS GIVEN THE GFS FORECAST AND DIRECTIONAL SHEAR AROUND 12Z SAT.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 308 PM EST WEDNESDAY...
SATURDAY EVENING THE BACK EDGE OF AN AREA OF PRECIPITATION
ASSOCIATED WITH SATURDAYS COLD FRONTAL PASSAGE WILL BE EXITING
SOUTHSIDE VIRGINIA...AND NEIGHBORING SECTIONS OF NORTH CAROLINA.
NORTHWEST FLOW BEHIND THE FRONT WILL HELP GENERATE SOME UPSLOPE
RAIN/SNOW SHOWERS ACROSS PARTS OF SE WV...THAT WILL ISOLATED IN
COVERAGE AND LAST THROUGH EARLY SUNDAY MORNING.
SUNDAY THROUGH MONDAY...OUR NEXT NORTHERN STREAM CLIPPER SYSTEM WILL
RACE THROUGH THE OHIO VALLEY AND THEN THE CENTRAL APPALACHIANS.
PRECIPITATION IS EXPECTED TO START AS RAIN SHOWERS ACROSS SE WV ON
SUNDAY AFTERNOON. DURING THE OVERNIGHT HOURS...LOOK FOR COVERAGE TO
SPREAD FARTHER EAST AND BECOME A MIX OF RAIN AND SNOW...THE THE BULK
OF THE SNOW CONFINED TO SE WV...NEIGHBORING COUNTIES OF SW VA...AND
THE NORTHERN MOUNTAINS OF NC. NORTHWEST FLOW ON THE BACK SIDE OF THE
SYSTEM WILL ALLOW FOR A CONTINUATION OF UPSLOPE RAIN/SNOW SHOWERS
ACROSS THE MOUNTAINS ON MONDAY THAT WILL TREND TO ISOLATE RAIN
SHOWERS BY THE AFTERNOON.
TUESDAY INTO WEDNESDAY...HIGH PRESSURE WILL BUILD OVER AND THEN EAST
OF THE REGION. THIS WILL ALLOW FOR AN END OF THE PRECIPITATION...AND
TREND TOWARDS MILDER CONDITIONS BY WEDNESDAY WITH SOUTHERLY FLOW
ESTABLISHING ITSELF. CLOUD COVER WILL ALSO INCREASE ON WEDNESDAY AS
LOW LEVEL FLOW GAINS A FETCH OF THE ATLANTIC AND MOISTURE IS
ADVECTED UPSLOPE ALONG THE CREST OF THE BLUE RIDGE.
&&
.AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
AS OF 1120 AM EST WEDNESDAY...
MVFR EXPECTED WITH POCKETS OF IFR/LIFR THIS AFTERNOON IN CLOUDS
AND CONVECTION. SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE
THIS AFTERNOON INTO TONIGHT. THE COLD FRONT WILL APPROACH BLF AND
LWB THIS EVENING AND SHOULD BE EAST OF LYH AND DAN BY 09Z. A BKN
LINE OF SHOWERS AND THUNDERSTORMS LIKELY TO ACCOMPANY THE FRONTAL
PASSAGE...WITH TEMPORARY IFR TO MVFR CONDITIONS. FOLLOWING THE
COLD FRONT EXPECT A RETURN TO VFR WEATHER FOR LATE TONIGHT INTO
THURSDAY.
ANOTHER WARM FRONT WILL AFFECT THE REGION FRIDAY...WITH POSSIBLE
MVFR CIGS. A STRONG COLD FRONT SHOULD ARRIVE IN THE LATE FRIDAY
NIGHT-SAT TIME FRAME RESULTING IN WIDESPREAD MVFR/IFR DUE TO
SHOWERS AND THUNDERSTORMS.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS/KK
NEAR TERM...AMS/KK
SHORT TERM...WP
LONG TERM...DS
AVIATION...AMS/KK/PM
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
622 PM CST THU MAR 1 2012
UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND FRIDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW LOW PRESSURE
MOVING OVER THE EASTERN GREAT LAKES...BUT WITH SURFACE TROUGHING
EXTENDING WEST INTO NORTHERN WISCONSIN. THE COMBO OF WEAK CYCLONIC
FLOW AND THERMAL TROUGHING IN THE LOW LEVELS HAS LEAD TO A ROBUST
STRATUS DECK THAT HAS HELD FIRM THROUGH EARLY THIS AFTERNOON. SOME
HOLES IN THE CLOUDS HAVE TRIED TO DEVELOP OVER THE LAKESHORE WITHOUT
MUCH LUCK. MEANWHILE...PLENTY OF INCOMING CONCERNS UPSTREAM.
NORTHERN STREAM SHORTWAVE IS SLOWLY MOVING EAST OVER THE
MONTANA/N.D. BORDER WITH LIGHT SNOW SPREADING ACROSS N.D. FARTHER
SOUTH...WEAK SHORTWAVE IMPULSES ARE MOVING WITHIN FAST SW FLOW OVER
THE CENTRAL PLAINS. ONE DISTURBANCE IS PRODUCING LIGHT SNOW OVER NE
NEBRASKA AND NW IOWA. FINALLY...THE STRONGEST SHORTWAVE IS RAPIDLY
MOVING EAST OVER UTAH/COLORADO...AND SNOW AMOUNTS/HEADLINES WITH
THIS FEATURE WILL BE THE MAIN FORECAST CONCERN.
TONIGHT...NORTHERN STREAM SHORTWAVE WILL MOVE ACROSS NORTH DAKOTA
INTO MINNESOTA AND PUSH AN UPPER LEVEL FRONT INTO NORTHWEST
WISCONSIN LATE TONIGHT. FORCING IS PRETTY WEAK...BUT GUIDANCE IS
OPTIMISTIC ABOUT GENERATING LIGHT SNOW ALONG IT. UPSTREAM OBS SNOW
THE POTENTIAL FOR LIGHT SNOW...SO WILL KEEP IT IN THE FORECAST AFTER
06Z. MEANWHILE...RELATIVELY WEAKER SOUTHERN STREAM IMPULSES WILL
RACE NORTHEAST INTO THE WESTERN GREAT LAKES. LIGHT SNOW OVER NE
NEBRASKA MAY MAKE A RUN AT CENTRAL OR EAST-CENTRAL WISCONSIN LATE AS
WELL. CONFIDENCE NOT QUITE AS HIGH WITH THIS FEATURE AS THE ONE
FARTHER NORTH...SO WILL SHOW LOWER POPS. NOT EXPECTING MUCH ACCUMS
WITH EITHER FEATURE THOUGH...PERHAPS A COUPLE TENTHS.
OTHERWISE...ANTICIPATE THE BACK EDGE OF THE LOW STRATUS WILL
ACCELERATE NORTHEAST OVER THE NORTHERN MISSISSIPPI VALLEY EARLY
TONIGHT. LOW LEVEL WIND FIELDS BECOME WEAK SO THINK THE LOW
OVERCAST WILL HANG AROUND. IF THEY DO CLEAR OVER CENTRAL AND
EAST-CENTRAL WISCONSIN (HIGHEST PROBABILITY)...MID AND HIGH CLOUDS
WILL KEEP THE SKIES OVERCAST. LOWS IN THE MID 20S TO THE LOWER 30S.
FRIDAY...CENTRAL ROCKIES SHORTWAVE WILL BE MOVING ACROSS THE CENTRAL
PLAINS AND NORTHEAST OVER THE MID-MISSISSIPPI VALLEY. IT WILL DRIVE
A RAPIDLY STRENGTHENING SURFACE LOW FROM SW MISSOURI TO NORTHEAST
INDIANA. NUISANT SMALL PRECIP CHANCES WILL LINGER OVER N-C
WISCONSIN AND CENTRAL WISCONSIN IN THE MORNING BUT THE MAIN SHOW
WILL ARRIVE IN THE AFTERNOON AS THE SURFACE LOW MOVES OVER ILLINOIS
AND INDIANA. INCREASING UPPER DIVERGENCE IN THE LEFT FRONT QUAD OF A
JETSTREAK...AND STRONG FGEN CENTERED AROUND 700MB ON THE NW FLANK OF
THE SURFACE LOW WILL LEAD TO PRECIP SPREADING NORTHEAST OVER CENTRAL
AND NORTHEAST WISCONSIN MID-AFTERNOON ONWARD. NEGATIVE EPV ABOVE
THIS FGEN LAYER WILL SUPPORT ENHANCED BANDING ACTIVITY WHICH COULD
LEAD TO LOCALLY HEAVIER SNOWFALL RATES. SOME RAIN MAY MIX IN WITH
THE SNOW OVER THE FOX VALLEY AND LAKESHORE AREAS WHERE TEMPS WILL BE
IN THE MID 30S AS THE PRECIP ARRIVES. BUT ONCE THE HEAVIER PRECIP
RATES MOVE IN...A TIGHTENING BAROCLINIC ZONE WILL LIKELY LEAD TO
RAPIDLY ACCUMULATING SNOW FOR THE EVENING COMMUTE. COULD SEE A
QUICK 1-3 INCHES OF HEAVY SNOW FOR THE FOX VALLEY AND LAKESHORE BY
00Z SATURDAY WITH LESSER AMOUNTS TO THE NORTHWEST. WILL HOIST A
WINTER STORM WATCH STARTING AT 3 PM FOR WINNEBAGO TO SOUTHERN
MARINETTE ON EAST.
.LONG TERM...FRI NGT THRU NXT THU. FAIRLY PROGRESSIVE MEAN FLOW
ACROSS THE COUNTRY AS ONE LONGWAVE TROF MOVES ACROSS THE ERN CONUS
THIS WEEKEND...TO BE FOLLOWED BY ANOTHER LONGWAVE TROF PUSHING
INTO THE WRN CONUS EARLY NXT WEEK. NE WI TO DEAL WITH INITIAL TROF
INTO THE WEEKEND...HOWEVER UPR RIDGING BETWEEN THE TWO TROFS WL
BRING A GOOD WARM-UP EARLY TO MID-WEEK. THE APPROACH OF A CDFNT
WED/THU WL BRING THE NXT BEST CHC OF SEEING WIDESPREAD PCPN.
MDLS CONT TO CONVERGE ON A STORM TRACK FROM TAKING A DEEPENING SFC
LOW ROUGHLY FROM SW LWR MI NEWD TO EXTREME SE ONTARIO FRI NGT.
ACCUMULATING SNOW WL CONT TO IMPACT PRIMARILY ERN WI WHERE AN ADDL
2 TO 4 INCHES IS PSBL DURING THE EVENING. CONVERSELY...WRN SECTIONS
OF THE FCST AREA (GENERALLY WEST OF HWY 51) WL BE LUCKY TO SEE AN
ADDL INCH OF NEW SNOW. STRONG CYCLONIC FLOW COMBINED WITH A SFC
TROF DROPPING SOUTH INTO WI WL KEEP AT LEAST A CHC OF SNOW SHWRS
ACROSS THE FCST AREA THRU THE OVRNGT PERIOD.
THE WEAK SFC TROF SAGS SWD TOWARD SRN WI ON SAT WITH A WEAKENING
CYCLONIC FLOW HANGING ON OVER THE WRN GREAT LKS. FURTHERMORE...THE
LONGWAVE TROF WL BE MOVING INTO THE REGION WITH SEVERAL EMBEDDED
SHORTWAVES PUSHING THRU WI. FINALLY...MID-LVL LAPSE RATES GET
PRETTY STEEP ADDING INSTABILITY TO THE ATMOSPHERE. ADD ALL THIS UP
AND WE ARE LOOKING AT A DECENT CHC OF SNOW SHWRS THROUGHOUT ALL OF
NE WI. WOULD NOT BE SURPRISED TO SEE A FEW LOCALLY HEAVIER SNOW
BURSTS WITH PERHAPS A QUICK ONE-HALF INCH TO AN INCH OF ACCUMULATION.
MAX TEMPS TO BE COOLER THAN PREV DAYS WITH READINGS TOPPING OUT IN
THE LWR TO MID 30S.
SNOW SHWRS SHOULD BECOME MORE ISOLATED IN NATURE SAT NGT AS THE SFC
TROF PULLS AWAY AND THE LOSS OF DAYTIME HEATING MINIMIZES THE
INSTABILITY. SKIES TO REMAIN MOSTLY CLOUDY THRU THE NGT...HOWEVER
ENUF COOL AIR TO HAVE SETTLED OVER THE REGION TO ALLOW TEMPS TO
DROP INTO THE TEENS NORTH/CENTRAL...NEAR 20 EAST-CENTRAL. THE
LONGWAVE TROF TO STILL BE SITUATED OVER THE GREAT LKS THRU SUNDAY...
THEREBY PROVIDING A MEAN NW FLOW ACROSS WI. A PROMINENT SHORTWAVE
IS FCST TO DIVE SE FROM MN TO NRN IL WITH EVEN A SEMBLENCE OF A WEAK
SFC LOW MOVING SE THRU IA. EXPECT TO SEE SCT SNOW SHWRS OVER MUCH OF
NE WI ON SUNDAY WITH MAX TEMPS ONLY REACHING THE MID 20S NORTH/
AROUND 30 CENTRAL/E-CENTRAL.
ANY SNOW SHWR ACTIVITY SHOULD DIMINISH SUNDAY EVENING AS THE
SHORTWAVE DIVES TOWARD THE OHIO RIVER VALLEY AND INSTABILITY
WEAKENS UPON SUNSET. AS HI PRES BUILDS ACROSS THE MIDWEST LATER
SUNDAY NGT...SKIES WL ATTEMPT TO BECOME PARTLY CLOUDY OVER AT LEAST
CENTRAL WI BRINGING ANOTHER COLD NGT TO THE FCST AREA. THE HI PRES
DRIFTS ACROSS WI ON MON AND WL BE SITUATED JUST TO OUR EAST BY 00Z
TUE. WINDS BACKING S-SW WL START TO TAP WARMER AIR TO OUR WEST...
BUT COOLS START TO THE DAY WL ONLY BRING MAX TEMPS ON MON INTO THE
30-35 DEG RANGE. AS THE HI PRES HEADS TOWARD THE ERN CONUS ON TUE...
A STRONG AREA OF LOW PRES WL BE MOVING ACROSS S-CENTRAL CANADA. A
TIGHT PRES GRADIENT TO EXIST ACROSS THE GREAT LKS...BRINGING
BLUSTERY CONDITIONS TO NE WI. THESE GUSTY S-SW WINDS WL ALSO DRAW
VERY MILD AIR INTO WI WITH 8H TEMPS CLIMBING TO NEAR +6C. DEPENDING
ON THE DEPTH OF THE SNOW COVER...MAX TEMPS SHOULD EASILY RISE INTO
THE 40S WITH ANY SNOW-FREE AREAS SURPASSING THE 50 DEG MARK.
THE NXT LONGWAVE TROF TO BE IN THE PROCESS OF PUSHING ACROSS THE
ROCKIES TUE NGT BEFORE REACHING THE NRN/CNTRL PLAINS ON WED.
PRECEDING THIS UPR TROF WL BE A CDFNT WHICH THE MDLS HAVE SOME
TIMING ISSUES WITH. LATEST TRENDS HAVE THIS FNT APPROACHING CENTRAL
WI BY WED AFTERNOON...THUS A NEED FOR CHC POPS ACROSS MOST OF NE
WI. ANOTHER MILD DAY WOULD HAVE ANY PCPN FALL AS RAIN WITH MAX
TEMPS TO RANGE FROM THE MID 40S NORTH TO AROUND 50 DEGS CENTRAL
AND EAST-CENTRAL WI. THE CDFNT DRIVES THRU MOST OF WI WED NGT WITH
A BAND OF LIGHT RAIN MIXING WITH AND CHANGING TO LIGHT SNOW AS
COOLER AIR ARRIVES BEHIND THE FNT. SOME DEBATE LINGERS AS TO
WHETHER THIS FNT WL BE ABLE TO CLEAR THE AREA BEFORE ANY SFC WAVES
CAN DEVELOP ON THE FNT TO SLOW ITS PROGRESS. HAVE USED A GENERAL
CONSENSUS FOR THU WHICH KEEPS THINGS DRY FOR NOW...BUT THU MAY
NEED TO BE RE-EVALUATED LATER AS THE 12Z ECMWF NOW DIGS AN UPR
TROF INTO THE CNTRL CONUS AND REVS UP A SFC LOW TOWARD CHICAGO.
&&
.AVIATION...1000 TO 2000 FT AGL CIGS EXPECTED ACROSS THE AREA
TONIGHT. THERE MAY BE SOME FREEZING DRIZZLE NORTH OF RRL AND AIG
THIS EVENING.
RDM
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WATCH FROM FRIDAY AFTERNOON THROUGH LATE FRIDAY
NIGHT FOR WIZ022-038>040-048>050-073-074.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
537 PM CST THU MAR 1 2012
.SHORT TERM...TONIGHT THROUGH SUNDAY
347 PM CST THU MAR 1 2012
AT 3 PM...THE WATER VAPOR IMAGERY AND PROFILER NETWORKS SHOW THAT
A SHORT WAVE TROUGH WAS MOVING ACROSS SOUTHWEST MINNESOTA AND
WESTERN IOWA. THE RUC SOUNDINGS CONTINUE TO SHOW THAT MUCH OF THE
SYNOPTIC AND ISENTROPIC LIFT ASSOCIATED WITH THIS WAVE GOES TO
SATURATION. THIS IS LIKELY THE REASON WHY THE RADARS ARE
INDICATING SOME ECHOS ACROSS SOUTH CENTRAL MINNESOTA AND NORTHEAST
IOWA. HOWEVER WITH THE AIR MASS DRY IN THE LOW LEVELS...NOT SEEING
ANYTHING REACHING THE GROUND. THIS WAVE WILL MOVE THROUGH SOUTHERN
WISCONSIN THIS EVENING...SO JUST LEFT A 20 PERCENT CHANCE OF
PRECIPITATION TO COVER THIS SYSTEM. FURTHER TO THE NORTHWEST...
ANOTHER SHORT WAVE TROUGH WAS MOVING THROUGH EASTERN NORTH DAKOTA.
THIS SYSTEM LOOKS TO BE TOO FAR NORTH AND WEST TO PRODUCE ANY
PRECIPITATION ACROSS EITHER SOUTHEAST MINNESOTA OR NORTH-CENTRAL
WISCONSIN. AS A RESULT...LOWERED THE PRECIPITATION CHANCES FOR
TONIGHT IN THESE AREAS. MEANWHILE BETWEEN THESE TWO SYSTEM WILL
LIKELY NOT SEE ANY PRECIPITATION...SO TOOK OUT THE PRECIPITATION
CHANCES OUT FOR THESE AREAS.
ON FRIDAY...THE 01.12Z MODELS ARE MUCH CLOSER TO COMING UP WITH A
CONSENSUS FORECAST. THE NAM/WRF HAS KEPT ITS IDEA THAT THERE WOULD
BE SOME PHASING BETWEEN THE NORTHERN AND SOUTHERN STREAMS...THUS...
IT HAS KEPT A STRONGER LOW PRESSURE SYSTEM. WHILE THIS HAS BEEN
CONSISTENT...IT HAS SHIFT THE SURFACE LOW MUCH FURTHER SOUTHEAST
WITH IT TRACKING FROM NORTHERN MISSOURI INTO SOUTHWEST LOWER
MICHIGAN. THIS TRACK IS MORE IN LINE WITH WHAT THE GFS...GEM...
ECMWF...AND UKMET HAVE BEEN SHOWING FOR THE PAST SEVERAL DAYS.
MEANWHILE THE GFS...GEM...ECMWF...AND UKMET ARE NOW SHOWING SOME
PHASING BETWEEN THE NORTHERN AND SOUTHERN STREAMS...SO THEY HAVE A
SIMILAR STRENGTH LOW TO THE NAM/WRF. WHILE THEY MADE THIS
CHANGE...THERE SURFACE LOW TRACK HAS REMAINED RATHER CONSISTENT.
ALL OF THE MODELS ARE SUGGESTING THAT THERE WILL BE STRONG 900 TO
700 MB FRONTOGENESIS ACROSS FAR EASTERN IOWA...NORTHWEST
ILLINOIS...AND SOUTHERN WISCONSIN. ABOVE THIS FRONTOGENESIS...
THERE IS SOME NEGATIVE EPV. AS A RESULT...EXPECTING TO SEE SOME
SLANTWISE CONVECTION TO DEVELOP. THIS INTERSECTS THE -15C OMEGA...SO
THERE WILL BE POSSIBILITY OF 1 TO 2 INCH AN HOUR SNOW RATES. THE
01.15Z SREF DOES SUGGEST THAT THERE WILL BE SOME PROBABILITIES FOR
THIS JUST TO THE EAST OF OUR FORECAST AREA. WITH ALL OF THIS IN
MIND...THINKING THAT THERE WILL BE A BAND OF 2 TO 4 INCHES OF SNOW
EAST OF A DUBUQUE IOWA TO WAUTOMA WISCONSIN LINE. IF THESE SNOW
TOTALS STILL LOOK REALISTIC TONIGHT...WE MAY HAVE TO ISSUE A
WINTER WEATHER ADVISORY FOR THIS AREA. ONE CONCERN ABOUT DOING
THIS IS THAT THE TEMPERATURES ARE ABOVE FREEZING AND THEY MAY HAVE
A HARD TIME ACCUMULATING IF THE RATES ARE NOT HIGH ENOUGH.
FROM FRIDAY NIGHT INTO SUNDAY...IT CONTINUES TO LOOK LIKE A LONG
WAVE TROUGH WILL BE LOCATED ACROSS THE REGION. EMBEDDED WEAK SHORT
WAVE TROUGHS IN THIS MAIN WAVE MAY PRODUCE PERIODIC CHANCES FOR
LIGHT SNOW. OVERALL...IF THE SNOW DOES OCCUR...NOT EXPECTING TOO
MUCH ACCUMULATIONS FROM THESE SYSTEMS.
.LONG TERM...SUNDAY NIGHT THROUGH THURSDAY
347 PM CST THU MAR 1 2012
ON TUESDAY...THE MODELS ARE CONTINUING TO INDICATE THAT A 500 MB
HIGH WILL DEVELOP ACROSS THE SOUTHEAST UNITED STATES. SOUTHERLY
WINDS ON THE BACKSIDE OF THIS HIGH WILL BRING WELL ABOVE NORMAL
TEMPERATURES INTO THE FORECASTS AREA. WE MAY SEE TWO TO THREE DAYS
WITH HIGH TEMPERATURES IN THE 50S. THERE MAY BE EVEN A FEW AREAS
THAT SEE TEMPERATURES IN THE 60S. SINCE THE ALL BLEND STILL HAS
SOME COLD SOLUTIONS IN IT...TRENDED THE TEMPERATURES FROM TUESDAY
NIGHT INTO WEDNESDAY TOWARD THE CONSALL INSTEAD OF THE ALL BLEND.
&&
.AVIATION...TONIGHT AND FRIDAY
537 PM CST THU MAR 1 2012
MVFR STRATUS THAT WAS OVER THE TAF SITES MIXED OUT WITH DAYTIME
HEATING...THOUGH SOME STILL REMAINS PRESENT OVER NORTHEAST IOWA
INTO FAR SOUTHWEST WISCONSIN. WITH WINDS AT 2000-3000 FT ABOVE
THE GROUND TURNING SOUTHEAST...AM CONCERNED THAT THIS STRATUS
COULD MOVE BACK INTO THE TAF SITES. HOWEVER...THERE IS ALSO
CLEARING AND DRIER AIR COMING NORTHWARD FROM FAR EASTERN ILLINOIS
WHICH COULD BREAK THE STRATUS UP. THEREFORE...HAVE ONLY WENT WITH
A SCATTERED MVFR DECK THIS EVENING AT BOTH TAF SITES. LATE THIS
EVENING...A TROUGH OF LOW PRESSURE OVER WESTERN MINNESOTA IS
FORECAST TO APPROACH THE TAF SITES. SNOW AHEAD OF THIS TROUGH
OVER FAR NORTHWEST IOWA COULD IMPACT KRST...AND HAVE INCLUDED THIS
BY A TEMPO GROUP OF MVFR VISIBILITIES AND CEILINGS FOR 03-06Z. ANY
OF THIS SNOW SHOULD STAY NORTH OF KLSE. MVFR CEILINGS ARE PRESENT
ALONG THE TROUGH...WHICH SHOULD MOVE INTO THE TAF SITES SHORTLY
AFTER 06Z. THE TROUGH IS EXPECTED TO MOVE THROUGH THE TAF SITES
BETWEEN 09-14Z. INCREASING NORTHWEST WINDS BEHIND THE TROUGH TO
8-13KT WILL BRING DRIER AIR IN FROM THE DAKOTAS...HELPING TO BRING
CEILINGS UP. IN FACT...ANTICIPATING KRST TO CLIMB TO VFR BY 18Z.
WOULD NOT BE SURPRISED IF KLSE DOES TOO...BUT KLSE WILL BE CLOSER
TO A LOW PRESSURE SYSTEM COMING UP THROUGH ILLINOIS...PREVENTING
MOISTURE FROM CLEARING OUT AS FAST. ANY SNOW FROM THIS SYSTEM
EXPECTED TO STAY SOUTHEAST OF KLSE.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
347 PM CST THU MAR 1 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
353 PM CST WED FEB 29 2012
.SHORT TERM...LATE THIS AFTERNOON THROUGH SATURDAY NIGHT
314 PM CST WED FEB 29 2012
AT 3 PM...A 913 MB SURFACE LOW WAS LOCATED JUST EAST OF ROCHESTER
MINNESOTA. PRECIPITATION AND WARMER AIR CONTINUES TO ROTATE AROUND
THIS LOW PRESSURE AREA. IN ADDITION TO THE WARM AIR...THE INFRARED
SATELLITE IMAGERY AND MODEL SOUNDINGS ARE SHOWING THAT WE ARE
LOSING OUR ICE CRYSTAL SEEDING. THIS IS GREATLY COMPLICATING THE
PRECIPITATION TYPE FORECASTING. IN AREAS WHERE THE REFLECTIVITIES
ARE GREATER THAN 30 DECIBELS...THE PRECIPITATION IS IN THE FORM OF
SNOW. AT THIS TIME...IT LOOKS LIKE UP TO AN INCH OF ADDITION SNOW
WILL BE POSSIBLE EAST OF AN EAU CLAIRE TO DUBUQUE LINE...AND SOUTH
OF A LINE FROM CHARLES CITY IOWA TO LANCASTER WISCONSIN. DUE TO
THIS SNOW...WILL KEEP THE WINTER WEATHER HEADLINES RUNNING THROUGH
6 PM TONIGHT. ELSEWHERE...THE PRECIPITATION IS MAINLY IN THE FORM
OF RAIN OR DRIZZLE. THERE HAS EVEN BEEN A FEW REPORTS OF FREEZING
DRIZZLE OR RAIN ON THE HIGHER ELEVATIONS OF SOUTHEAST MINNESOTA...
NORTHEAST IOWA...AND IN THE BLUFF AREAS OF WESTERN WISCONSIN. WITH
THIS BEING SO HIT OR MISS JUST HANDLING THIS AS A SPECIAL WEATHER
STATEMENT.
SINCE WE CONTINUE TO SEE SUSTAINED WINDS IN THE 25 TO 35 MPH RANGE
AND OCCASIONAL WIND GUSTS UP TO 45 MPH...WILL LEAVE THE WIND
ADVISORY UP THROUGH 6 PM TODAY ACROSS NORTHEAST IOWA AND SOUTHWEST
WISCONSIN.
ON THURSDAY NIGHT AND FRIDAY...THE 29.12Z NAM/WRF CAME IN MUCH
STRONGER...WETTER...AND FURTHER NORTHWEST THAN THE GFS...ECWMF...AND
UKMET. THE MAIN REASON FOR THIS IS THAT IT PHASES THE NORTHERN AND
SOUTHERN STREAMS TOGETHER. MEANWHILE THE REMAINING MODELS HAVE ONE
SHORT WAVE TROUGH MOVING THROUGH THURSDAY NIGHT...AND TWO OTHER
SHORTS SHIRTING THE AREA /ONE TO THE NORTH AND ANOTHER TO THE
SOUTHEAST/ ON FRIDAY. SINCE THE NAM/WRF HAS BEEN PHASING THE
NORTHERN AND SOUTHERN STREAMS TOO MUCH...THE FORECAST WAS TRENDED
TOWARD THE OTHER MODEL SOLUTIONS. SNOW TOTALS ON THURSDAY
NIGHT...LOOK TO LESS THAN INCH. NOT AS SURE ON FRIDAY DUE TO THE
POTENTIAL OF RAIN POSSIBLY MIXING IN WITH THE SNOW AT TIMES.
FROM FRIDAY NIGHT INTO SATURDAY...A LONG WAVE TROUGH WILL MOVE
EAST ACROSS THIS AREA. THERE APPEARS THAT THERE WILL BE ENOUGH
MOISTURE AND LIFT ASSOCIATED WITH THIS SYSTEM TO MAINTAIN SOME
LIGHT RAIN AND SNOW IN THE FORECAST. AS A RESULT...KEPT THE
PRECIPITATION CHANCES IN THE 20 TO 30 PERCENT RANGE.
.LONG TERM...SUNDAY THROUGH TUESDAY
314 PM CST WED FEB 29 2012
ON TUESDAY...THE 29.12Z MODELS CONTINUE TO SHOW THAT THERE WILL BE
STRONG WARM AIR ADVECTION AHEAD OF THE SYSTEM MOVING OUT OF THE
NORTHERN PLAINS. BOTH THE ECMWF ARE SUGGESTING THAT TEMPERATURES
ALONG AND SOUTH OF THE INTERSTATE 90 CORRIDOR WILL CLIMB INTO THE
50S. WHILE THESE TEMPERATURES LOOK REASONABLE...THERE IS SOME
CONCERN ON HOW WARM TEMPERATURES WILL GET ACROSS THE AREAS WHICH
RECEIVED THE DEEP SNOW PACK LAST NIGHT. THE ALL BLEND AND CONS
BLEND WOULD SUGGEST TEMPERATURES IN THE UPPER 40S. HOWEVER THIS
LOOKS TO BE TOO WARM WITH MUCH SNOW ON THE GROUND...SO COOLED THE
TEMPERATURES DOWN INTO THE LOWER AND MID 40S.
&&
.AVIATION...THROUGH 18Z THURSDAY
1222 PM CST WED FEB 29 2012
LATEST 17Z SURFACE ANALYSIS INDICATES SURFACE LOW OVER SOUTH
CENTRAL MINNESOTA WITH THE LATEST METARS SHOWING MVFR TO IFR
CEILINGS ACROSS MUCH OF THE AREA...WITH ISOLATED POCKETS OF LIFR
CONDITIONS. MAIN CONCERN THROUGH TAF PERIOD IS LOW LEVEL STRATUS
DECK WRAPPING AROUND SURFACE LOW AND INTO THE KRST AND KLSE TAF
SITES. LATEST 29.12Z NAM/GFS AND 29.15Z RUC DO INDICATE SURFACE
LOW TO SLOWLY MOVE EAST INTO WESTERN MICHIGAN BY 06Z THURSDAY.
BUFKIT SOUNDINGS FROM THE DETERMINISTIC MODELS SHOW LOW LEVEL
STRATUS TO WRAP AROUND SURFACE LOW AND INTO THE KRST AND KLSE TAF
SITES THROUGH TAF PERIOD. HAVE INTRODUCED MVFR/IFR CEILINGS
THROUGH THE TAF FORECAST PERIOD. LATEST MOSAIC RADAR INDICATING
SNOW BAND OVER SOUTHEAST MINNESOTA AND SOUTHWEST WISCONSIN WITH
VISIBILITIES BEING REDUCED TO ONE MILE TO TWO MILES PER LATEST
METARS. THIS BAND SHOULD LIFT NORTHEAST OF BOTH TAF SITES BY 20Z
WEDNESDAY AND ALLOW FOR VISIBILITIES TO IMPROVE AFTER 20Z.
&&
.HYDROLOGY...
346 AM CST WED FEB 29 2012
A GOOD DEAL OF PRECIPITATION FELL LAST NIGHT AS THE MAIN SURGE OF
MOIST AIR ARRIVED. MORNING PRECIPITATION REPORTS INDICATE BETWEEN A
HALF-INCH AND THREE-QUARTERS OF AN INCH ACROSS NORTHEAST IOWA AND
SOUTHWEST WISCONSIN. SOME MINOR WITHIN BANK RISES ON TRIBUTARY
CREEKS AND RIVERS HAS OCCURRED.
FROM SOUTHEAST MN INTO CENTRAL AND NORTHERN WI...AMOUNTS WERE HIGHER
WITH WIDESPREAD REPORTS BETWEEN 1 AND 1.5 INCHES. SOME SPOTS SAW
JUST OVER 1.75 INCHES OF WATER. THE HIGHEST AMOUNTS WERE SEEN FROM
THE ZUMBRO AND WHITEWATER WATERSHEDS...INTO THE TREMPEALEAU AND
BLACK RIVER BASINS. SIGNIFICANT RISES ARE OCCURING IN THESE RIVER
SYSTEMS...WITH SOME SPOTS GETTING CLOSE TO BANKFULL AND FLOOD STAGE.
CURRENTLY...THE SYSTEM IS SPINNING OVERHEAD...DROPPING MORE SNOW AND
DRIZZLE. THIS SHOULD NOT AMOUNT TO A GREAT DEAL MORE WATER CONTENT.
SO THE FEELING IS WE WILL SEE THE MAJORITY OF RIVERS PEAK AND FALL
TONIGHT...IF THEY HAVE NOT ALREADY DONE SO.
THIS RAINFALL ON THE FROZEN SOIL ALSO LED TO WIDESPREAD PONDING OF
WATER...AS IT COULD NOT SOAK IN.
THE STORM DROPPED OVER 15 INCHES OF SNOW ACROSS THE UPPER BLACK
RIVER BASIN...SO AS THIS MELTS...EXPECT THE BLACK TO CONTINUE
RUNNING HIGHER THAN NORMAL INTO NEXT WEEK.
WE ARE ALSO MONITORING THE NEXT STORM SYSTEM FOR THE END OF THE
WEEK. ANY ADDITIONAL WATER COULD LEAD TO RENEWED RISES.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
314 PM CST WED FEB 29 2012
WI...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR
WIZ032>034-043-044-054-055-061.
WIND ADVISORY UNTIL 6 PM CST THIS EVENING FOR WIZ054-055-061.
WINTER STORM WARNING UNTIL 6 PM CST THIS EVENING FOR WIZ017-029.
MN...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR MNZ079.
IA...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR
IAZ008>011-018-019-029-030.
WIND ADVISORY UNTIL 6 PM CST THIS EVENING FOR IAZ008>011-018-019-
029-030.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...DTJ
HYDROLOGY...WELVAERT
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
245 PM CST WED FEB 29 2012
.SHORT TERM...TONIGHT AND THURSDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW OCCLUDED LOW
PRESSURE NOW ENTERING SOUTHWEST WISCONSIN THIS AFTERNOON.
PRECIPITATION WITH THIS MAIN CIRCULATION HAS BEEN BLOSSOMING ACROSS
CENTRAL AND NORTHEAST WISCONSIN THIS AFTERNOON...WITH VSBYS DROPPING
TO 3/4SM IN LIGHT SNOW FROM WISCONSIN RAPIDS TO WAUSAU.
TEMPERATURES AND DEWPOINTS HAVE WARMED INTO THE MIDDLE AND UPPER 30S
OVER THE FOX VALLEY...BAYSHORE...AND LAKESHORE...WHERE PRECIP HAS
BEEN MAINLY RAIN AND DRIZZLE THIS AFTERNOON. AS THE LOW TRACKS
ACROSS CENTRAL WISCONSIN THIS EVENING...PRECIP TYPE AND
ACCUMULATIONS ARE THE MAIN FORECAST CONCERNS.
TONIGHT...OCCLUDED LOW PRESSURE WILL MOVE ENE ACROSS CENTRAL
WISCONSIN THIS EVENING. WILL NO LONGER BE FEELING THE EFFECTS OF
THE WARM CONVEYOR BELT...BUT MOISTURE WRAPPING ALL THE WAY AROUND
INTO THE COMMA HEAD WILL LEAD TO WIDESPREAD PRECIPITATION CONTINUING
FOR MUCH OF THE EVENING. THE HEAVIEST PRECIP SHOULD FALL WITHIN AND
ON THE NORTHERN FLANK OF THE CIRCULATION CENTER WHICH SHOULD RUN
FROM ABOUT MARSHFIELD TO DOOR COUNTY. BECAUSE COLDER AIR TO -6C AT
850MB WILL FILTER ACROSS NORTHEAST WISCONSIN...PRECIPITATION TYPE
WILL CHANGE TO ALL SNOW...EVEN NEXT TO THE LAKESHORE. AN ADDITIONAL
INCH OR TWO OF SNOW WILL BE POSSIBLE NORTHWEST OF THE FOX VALLEY AND
BAY SHORE AND OVER THE HIGHER TERRAIN THROUGH THIS EVENING WHERE
TEMPERATURES WILL FALL INTO THE 31-34 DEGREE RANGE. ABOVE FREEZING
TEMPERATURES WILL INITIALLY LIMIT ACCUMS OVER EAST-CENTRAL AND FAR
NORTHEAST WISCONSIN...BUT THOSE LOCATIONS COULD STILL SEE A HALF
INCH TO AN INCH AS TEMPS FALL THIS EVENING. BECAUSE OF THE
POSSIBILITY OF ANOTHER COUPLE INCHES OF SNOW WHICH COULD LEAD TO
RENEWED TRAVEL WOES...WILL LEAVE WINTER WEATHER HEADLINES ALONE.
SNOW WILL BE PUSHING ON TO THE EAST BY LATE IN THE EVENING LEAVING
CLOUDY SKIES PREVAILING ACROSS THE REGION. PLENTY OF FLURRY
ACTIVITY EXISTING ALL THE WAY TO WESTERN MINNESOTA...SO WILL HAVE TO
LEAVE A MENTION THROUGH THE REST OF THE NIGHT. LOW TEMPS RANGING
FROM THE MID 20S WEST TO AROUND 30 EAST.
THURSDAY...LOW PRESSURE WILL CONTINUE EAST TO THE EASTERN GREAT
LAKES. CYCLONIC FLOW WILL HANG AROUND FOR MUCH OF THE MORNING...SO
FIGURE SKY CONDITIONS WILL REMAIN CLOUDY. SOME BREAKS IN THE CLOUDS
ARE LIKELY IN THE AFTERNOON WHEN THE LOW LEVEL MOISTURE THINS OUT
AND THE FLOW BECOMES LIGHT AND WESTERLY. HIGHS IN THE MID 30S TO
AROUND 40F.
.LONG TERM...THU NGT THRU NXT WED. MDLS HAVE COME INTO BETTER
AGREEMENT WITH REGARDS TO A BROAD LONGWAVE TROF PUSHING ACROSS THE
CONUS DURING THE FIRST HALF OF THE EXTENDED PERIOD. STILL WATCHING
A SYSTEM PRECEDING THIS TROF WHICH COULD BRING A MIX OF PCPN TYPES
TO NE WI ON FRI. MEAN FLOW TENDS TO FLATTEN BY EARLY NXT WEEK
ALLOWING FOR MILD PACIFIC AIR TO RUSH ACROSS THE CONUS. DEPENDING
ON THE AMOUNT OF SNOW STILL ON THE GROUND...SOME PARTS OF CNTRL/
E-CNTRL WI COULD PUSH THE 50 DEG MARK BY TUE BEFORE THE NXT CDFNT
ARRIVES WITH THE NXT CHC OF PCPN.
THE LONGWAVE TROF MOVES THRU THE ROCKIES THU NGT AND ENTERS THE
PLAINS TOWARD DAYBREAK. AS THIS OCCURS...A SFC LOW IS FCST TO DVLP
OVER THE CNTRL/SRN PLAINS AND MOVE NE TOWARD THE OZARKS/MO VALLEY
AREA. WAA TO OVERSPREAD WI WITH ENUF MSTR EVIDENT TO BRING PCPN
INTO PARTS OF THE FCST AFTER MIDNGT. TEMPS WOULD BE COLD ENUF SUCH
THAT ANY PCPN WOULD BE SNOW...BUT ANY ACCUMULATIONS WOULD BE VERY
MINOR.
QSTNS REMAIN AS TO THE EXACT TRACK OF THE SFC LOW AS IT HEADS NE
TOWARD SRN SECTIONS OF THE GREAT LKS ON FRI. THE NAM REMAINS A
WESTWARD TRACK OUTLIER PRIMARILY DUE TO TRYING TO PHASE A NRN
PIECE OF SHORTWAVE TROF WITH THE SFC LOW. THE GEM MODEL TRACKS THE
SFC LOW NEWD INTO SW/CNTRL SECTIONS OF LWR MI...WHILE THE GFS/UKMET/
ECMWF NOW ALL PREFER A MORE ERN ROUTE AND TAKE THE LOW PRES TOWARD
NE INDIANA/SE LWR MI. SINCE THIS SYSTEM IS JUST COMING ASHORE TODAY
(WED)...TRACK WL LIKELY WAFFLE A BIT MORE BEFORE SETTLING DOWN...
THUS HAVE LEANED TOWARD THE MORE CONSISTENT GFS/UKMET/ECMWF WHICH
WOULD BRING AN INCH OR TWO OF ACCUMULATION TO NE WI. HAVE RAISED
POPS TO LIKELY FOR ALMOST THE ENTIRE FCST AERA AND GONE MORE SNOW
THAN RAIN FOR ERN WI.
SNOW CHCS TO CONT THRU AT LEAST FRI EVENING BEFORE TAPERING OFF
FROM SOUTH TO NORTH AS THE SFC LOW MOVES INTO SE ONTARIO. COULD
SEE AN ADDL INCH OR TWO OF ACCUMULATION...MAINLY ACROSS THE NRN
WI. SYSTEM CONTS TO LIFT NE TOWARD THE CANADIAN MARITIMES ON SAT
WITH A TRAILING SHORTWAVE TROF/EMBEDDED SHORTWAVES STILL MOVING
THRU WI. WL NEED TO CARRY SOME SNOW SHWR ACTIVITY THRU THE DAY
WITH THE BETTER CHCS ACROSS THE NORTH AS WINDS TURN W-NW WITH SOME
PSBL LK ENHANCEMENT. TEMPS TO CONT A DOWNWARD TREND WITH HI TEMPS
GENERALLY IN THE 30-35 DEG RANGE.
THE LONGWAVE TROF IS THEN EXPECTED TO MVOE THRU THE RGN SAT NGT
INTO SUNDAY WITH VARIOUS PIECES OF SHORTWAVE ENERGY DROPPING SE IN
THE NW FLOW ALOFT. NE WI ALSO RESIDE UNDER THE FAVORABLE LEFT EXIT
RGN OF THE UPR JET FOR ADDED LIFT. EXPECT TO SEE AT LEAST ISOLATED
SNOW SHWRS ACROSS THE FCST AREA BOTH SAT NGT AND SUNDAY WITH A
MINOR ACCUMULATION PSBL WHERE ANY SNOW SHWRS BECOME MORE PRONOUNCED.
SUNDAY ALSO LOOKS TO BE THE COLDEST DAY OF THE EXTENDED FCST WITH
MAX TEMPS MAINLY IN THE 25-30 DEG RANGE. A WEAK AREA OF HI PRES IS
THEN FCST TO BUILD ACROSS THE WRN GREAT LKS RGN SUNDAY NGT AND
RESIDE TO OUR EAST ON MON. ANY LINGERING SNOW SHWRS SHOULD END
RATHER QUICKLY WITH WINDS BACKING TO THE S-SW BY MON ON THE
BACKSIDE OF THE HI PRES. COOL START TO MON WL LIMIT AMOUNT OF
DIURNAL WARMING EVEN AS A SURGE OF WARMER AIR ALOFT PUSHES INTO
THE STATE.
INCREASING S-SW WINDS MON NGT WL SEND A WRMFNT NWD WITH MUCH
MILDER AIR STREAMING INTO NE WI. A NEW...BROAD UPR TROF IS PROGGED
TO MOVE INTO THE CNTRL CONUS ON TUE AND HELP PUSH A CDFNT ACROSS
THE UPR MIDWEST. MOST OF THE FORCING/LIFT APRS TO BE BEHIND THE
FNT...THUS HAVE KEPT TUE DRY AND MILD WITH MAX TEMPS SURPASSING
THE 40 DEG MARK. IF CLOUDS CAN STAY AWAY LONG ENUF...PARTS OF
CNTRL/E-CNTRL WI COULD REACH 50 DEGS. THE CDFNT PUSHES THRU WI TUE
NGT AND THEN THE MDLS DVLP SEVERAL WAVES ALONG THE FNT WHICH WOULD
HELP FOCUS PCPN ACROSS THE FCST AREA ON WED. BASED ON PROJECTED
LOCATION OF THE CDFNT AND SFC WAVES...HAVE GONE WITH A HI CHC POP
FOR THE VAST MAJORITY OF NE WI. ANOTHER PBLM WL BE PCPN TYPE AS
COOLER AIR TO SETTLE OVER THE NW HALF OF WI. HAVE GONE WITH A
RAIN/SNOW MIX FOR N-CNTRL WI...BUT KEPT PCPN AS ALL RAIN IN THE
CENTRAL AND EAST.
&&
.AVIATION...STRONG LOW PRESSURE WILL PASS ACROSS THE STATE THROUGH
THIS EVENING BEFORE DEPARTING TO THE EAST. HEAVY SNOW HAS SHIFTED
INTO THE UPPER PENINSULA...BUT WRAP AROUND SNOW SHOWERS WILL PASS
OVER THE TAF SITES THIS AFTERNOON INTO EARLY THIS EVENING. IFR TO
LIFR VSBYS POSSIBLE IN ANY SNOW SHOWERS. ONCE THE SNOW
ENDS...FLURRIES SHOULD HANG ON THROUGH MUCH OF THE EVENING.
VARIABLE CIGS UPSTREAM SUGGEST HIGH END IFR TO MVFR CIGS THROUGH
THE REST OF THE TAF PERIOD UNDER CYCLONIC FLOW.
MPC
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL 6 PM CST THIS EVENING FOR WIZ005-
010>013-018-019-030.
WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR WIZ035-
036.
&&
$$
MPC/AK
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1222 PM CST WED FEB 29 2012
.SHORT TERM...
1116 AM CST WED FEB 29 2012
A BAND OF MODERATE TO HEAVY SNOW ROTATING AROUND SURFACE LOW OVER
SOUTH CENTRAL MINNESOTA WILL PROGRESS EASTWARD INTO NORTHEAST IOWA
AND SOUTHWEST WISCONSIN THIS AFTERNOON. THE COMBINATION OF SNOW
AND BLOWING SNOW WILL REDUCE VISIBILITIES TO LESS THAN A MILE
ACROSS THIS AREA. THEREFORE...WE WILL BE ISSUING A WINTER WEATHER
ADVISORY FOR NORTHEAST IOWA AND SOUTHWEST WISCONSIN THROUGH 6 PM.
.LONG TERM...SATURDAY THROUGH TUESDAY
346 AM CST WED FEB 29 2012
GOOD CONSENSUS AMONG 29.00Z MEDIUM RANGE MODELS FOR THE LONGWAVE
TROUGH TO SLOWLY PROGRESS EAST OF THE AREA SAT/SUN. A COLD LOW LEVEL
AIRMASS SETTLES OVER THE AREA FOR SAT INTO SUN. SFC-500MB FLOW
REMAINS CYCLONIC WITH SURGES OF MOISTURE/WEAK SHORTWAVES RIPPLING
SOUTHEAST THRU THE FLOW PASSING ACROSS THE REGION. SMALL -SN/FLURRY
CHANCES SAT/SUN LOOK REASONABLE AT THIS TIME. MODELS REMAIN IN GOOD
AGREEMENT FOR THE PATTERN TO BE PROGRESSIVE AND STRONG RIDGING ALOFT
AND BROAD LOWER LEVEL WARM ADVECTION TO SPREAD ACROSS THE NORTH
CENTRAL CONUS FOR MON/TUE. TEMPS LOOKING TO CLIMB WELL ABOVE NORMAL
FOR EARLY NEXT WEEK...AND THE WELL TRENDED WITH THE MODEL/ENSEMBLE
CONSENSUS DATA SET. AGAIN STAYED WITH THE MODEL/ENSEMBLE CONSENSUS
IN THE SAT-TUE FCST GRIDS.
&&
.AVIATION...THROUGH 18Z THURSDAY
1222 PM CST WED FEB 29 2012
LATEST 17Z SURFACE ANALYSIS INDICATES SURFACE LOW OVER SOUTH
CENTRAL MINNESOTA WITH THE LATEST METARS SHOWING MVFR TO IFR
CEILINGS ACROSS MUCH OF THE AREA...WITH ISOLATED POCKETS OF LIFR
CONDITIONS. MAIN CONCERN THROUGH TAF PERIOD IS LOW LEVEL STRATUS
DECK WRAPPING AROUND SURFACE LOW AND INTO THE KRST AND KLSE TAF
SITES. LATEST 29.12Z NAM/GFS AND 29.15Z RUC DO INDICATE SURFACE
LOW TO SLOWLY MOVE EAST INTO WESTERN MICHIGAN BY 06Z THURSDAY.
BUFKIT SOUNDINGS FROM THE DETERMINISTIC MODELS SHOW LOW LEVEL
STRATUS TO WRAP AROUND SURFACE LOW AND INTO THE KRST AND KLSE TAF
SITES THROUGH TAF PERIOD. HAVE INTRODUCED MVFR/IFR CEILINGS
THROUGH THE TAF FORECAST PERIOD. LATEST MOSAIC RADAR INDICATING
SNOW BAND OVER SOUTHEAST MINNESOTA AND SOUTHWEST WISCONSIN WITH
VISIBILITIES BEING REDUCED TO ONE MILE TO TWO MILES PER LATEST
METARS. THIS BAND SHOULD LIFT NORTHEAST OF BOTH TAF SITES BY 20Z
WEDNESDAY AND ALLOW FOR VISIBILITIES TO IMPROVE AFTER 20Z.
&&
.HYDROLOGY...
346 AM CST WED FEB 29 2012
AS MUCH AS 0.50 TO 1.00 INCH OF RAIN FELL ACROSS THE FCST AREA
LATE TUE/TUE NIGHT. THERE IS NOT MUCH SNOW AROUND CURRENTLY...BUT
THE GROUND REMAINS FROZEN WITH SOME RUN-OFF OCCURRING FROM THESE
RAINS. MINOR RISES ARE OCCURRING ON MANY OF THE THE TRIBUTARY CREEKS
AND STREAMS AROUND THE AREA BUT REMAIN WELL WITHIN BANKFULL EARLY
THIS MORNING. WATER LEVEL TRENDS WILL CONTINUE TO BE MONITORED.
ADDITIONAL RAIN AMOUNTS THRU TODAY WILL MAINLY BE LESS THAN ONE-
QUARTER INCH.
THERE IS STILL SOME ICE IN THE CREEKS AND RIVERS. WHILE LIKELY NOT A
LARGE THREAT AS ICE COVER IS WELL BELOW AVERAGE THIS YEAR...IF
ENOUGH RUNOFF OCCURS...IT IS POSSIBLE THAT A RISE IN THE WATER LEVEL
COULD BREAK UP SOME OF THE ICE...AND SEND IT DOWNSTREAM. UNSAFE ICE
CONDITIONS...AND EVEN SOME ICE JAMS...COULD OCCUR. BLOCKED OR FROZEN
CULVERTS MAY RESULT IN POOR DRAINAGE IN SOME SPOTS...SO THERE COULD
BE SOME LOCALIZED PONDING AS WELL.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
1116 AM CST WED FEB 29 2012
WI...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR
WIZ032>034-043-044-054-055-061.
WIND ADVISORY UNTIL 6 PM CST THIS EVENING FOR WIZ054-055-061.
WINTER STORM WARNING UNTIL 6 PM CST THIS EVENING FOR WIZ017-029.
MN...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR MNZ079.
IA...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR
IAZ008>011-018-019-029-030.
WIND ADVISORY UNTIL 6 PM CST THIS EVENING FOR IAZ008>011-018-019-
029-030.
&&
$$
SHORT TERM...DTJ
LONG TERM....RRS
AVIATION...DTJ
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1146 PM CST TUE FEB 28 2012
UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE
.UPDATE...WINTER STORM MOVING ALONG MORE OR LESS AS EARLIER
FORECAST. SURFACE LOW IS A BIT FURTHER SOUTH THAN THE 12Z MODELS
DEPCITED WITH BEST PRESSURE FALLS AT 03Z SUGGESTING IT WILL MOVE
TOWARDS LA CROSSE BY NOON TOMORROW. NAM FORECAST SOUNDINGS
VERIFIED BEST AGAINTS THE 00Z GRB AND MPX RADIOSONDES. IF THESE
FORECAST SOUNDINGS FOR OUR FORECAST AREA ARE ACCURATE THEN OUR
CURRENT ADVISORIES AND WARNINGS ARE WELL PLACED. SOME CONCERN THAT
WOOD, PORTAGE AND WAUPACA COUNTIES COULD GET MORE THAN SIX INCHES
OF SNOW IF IT STAYS SNOW THROUGH MOST OF THE NIGHT BUT ALL OF THE
MODELS BRING AN ELEVATED ABOVE FREEZING LAYER AROUND 850MB ACROSS
THAT AREA BY 06Z OR SO WHICH WOULD CHANGE THE SNOW OVER TO SLEET
OR FREEZING RAIN. DRY AIR NEAR THE LAKE MICHIGAN SHORE IS DELAYING
ARRIVAL OF PRECIPITATION BUT IT WILL GET THERE. SNOW WAS FALLING
OVER ALL OF THE AREA WITH THE EXCEPTION OF SOUTHERN WINNEBAGO
COUNTY WHERE IS WAS RAINING AND PARTS OF CALUMET COUNTY WHERE SOME
LIGHT FREEZING RAIN WAS REPORTED.
RDM
&&
.PREV DISCUSSION...ISSUED AT 644 PM CST TUE FEB 28 2012...
SHORT TERM...TONIGHT AND WEDNESDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY INDICATES LOW
PRESSURE EMERGING FROM THE ROCKIES INTO WESTERN KANSAS THIS AFTERNOON...WITH
ITS ASSOCIATED WARM FRONT LIFTING NORTH ALONG THE KS/NE BORDER AND
ACROSS MISSOURI. CONVECTION HAS DEVELOPED ALREADY AHEAD OF THE LOW
JUST AHEAD OF A POTENT DRY SLOT PUNCHING INTO NEBRASKA. CLOSER TO
HOME...LEADING EDGE OF RETURN MOISTURE IS NOW PUSHING INTO SOUTHERN
WISCONSIN A TAD AHEAD OF SCHEDULE...AS EVIDENT BY A BAND OF RAIN AND
SNOW. EARLIER MODERATE SNOW OVER N-C WISCONSIN IS HANGING ON ALONG
THE U.P. BORDER WHERE THEY RECEIVED 2-3 INCHES OF SNOW. BUT THE
MAIN PROBLEM FOR THIS FORECAST IS THE LOW OUT WEST AND HEAVY SNOW
POTENTIAL AS IT MOVES ACROSS THE REGION TONIGHT INTO WEDNESDAY.
TONIGHT...LOW PRESSURE OVER THE PLAINS WILL MOVE NORTHEAST AND
OCCLUDE AS IT MOVES INTO SOUTHWEST MINNESOTA BY 12Z WEDNESDAY.
AHEAD OF THE LOW...A 40-50KT LLJ WILL RAMP UP AND SHIFT INTO
NORTHERN ILLINOIS DURING THE OVERNIGHT HOURS. THIS LLJ WILL
TRANSPORT RICH GULF OF MEXICO MOISTURE NORTHEAST WITH PWATS OF
UPWARDS OF 0.75 INCHES REACHING INTO CENTRAL WISCONSIN. THIS IS
OVER 200 PCT OF NORMAL AND 2 STANDARD DEVIATIONS ABOVE NORMAL.
BEFORE THIS OCCURS THOUGH...LEADING EDGE OF THE RETURN MOISTURE ON
THE 285K SURFACE IS CREATING A BAND OF LIGHT RAIN AND SNOW WHICH
SHOULD APPROACH CENTRAL WISCONSIN LATE THIS AFTERNOON AND INTO THE
FOX VALLEY BY EARLY IN THE EVENING. WET BULB TEMPS HAVE BEEN RISING
THIS AFTERNOON...BUT FIGURING SNOW OVER CENTRAL WISCONSIN...AND
RAIN/SNOW MIX OVER EAST-CENTRAL WHERE ONSHORE FLOW WILL CONTINUE.
THE MAIN SURGE OF PRECIPITATION SHOULD NOT ARRIVE UNTIL LATE INTO
THE EVENING AND THE OVERNIGHT HOURS WHEN FORCING VIA LLJ AND
MID-LEVEL FGEN LIFTS INTO THE REGION. WITH MID-LEVEL LAPSE RATES OF
6.5-7 C/KM AND NEGATIVE EPV ABOVE THE FGEN LAYER...CONVECTION IS
DEFINITELY POSSIBLE WITH THE PRECIPITATION OVERNIGHT...AND UPSTREAM
OBS BEAR THIS OUT AS WELL. THERMAL PROFILES VARY WIDELY BETWEEN THE
WARMER GFS AND THE COLDER ECMWF/NAM. ALTHOUGH THERE IS PLENTY OF
WARM AIR TO OUR SOUTH...THE WARM LAYER IS MARGINALLY HIGH AT AROUND
800MB WHICH LEAVES THE POTENTIAL FOR CONVECTION TO WIPE OUT THAT
WARM NOSE...THEREBY KEEPING THE PROFILE NEAR OR JUST BELOW FREEZING
OVER CENTRAL AND EAST-CENTRAL WISCONSIN. AS A RESULT...HAVE BOOSTED
SNOW AMOUNTS OVER CENTRAL WISCONSIN AND THE NORTHERN FOX VALLEY. AM
MOST CONFIDENT OF RAIN/SLEET MIXING IN OVER KEWAUNEE AND MANITOWOC
COUNTIES THANKS TO THE LAKE INFLUENCE. SE WINDS WILL ALSO RAMP UP
OVERNIGHT WHICH COULD CREATE NEAR WHITE OUT VSBYS AT TIMES WITHIN
THE HEAVY SNOW. WILL UPGRADE DOOR COUNTY TO WARNING CRITERIA...AS
THEY DO SURPRISINGLY WELL IN CASES LIKE THIS...WHERE COLDER AIR AT
925MB WILL HANG ON THE LONGEST. OTHERWISE...CURRENT HEADLINES LOOK
GOOD FOR WARNING/ADVISORY CONFIGURATION. THE NEXT SHIFT WILL HAVE
TO MONITOR FOR UPGRADES FOR THE NEXT ROW OF COUNTIES SOUTH OF THE
WARNING IF CONVECTION DOES COOL THE COLUMN ENOUGH FOR A MOSTLY SNOW
PTYPE.
WEDNESDAY...OCCLUDED LOW PRESSURE WILL SLOW AND MOVE FROM SW
MINNESOTA TO WESTERN WISCONSIN OVER THE COURSE OF THE DAY. LOW
LEVEL WARM AIR WILL CONTINUE TO WRAP AROUND THE LOW INTO EASTERN
WISCONSIN DURING THE MORNING...WHILE THE DRY SLOW MOVES IN ALOFT.
MODERATE TO HEAVY SNOW WILL BE WIDESPREAD NORTH AND WEST OF THE DRY
SLOT OVER NORTHERN AND NORTHWEST WISCONSIN FOR MUCH OF THE MORNING.
BUT FARTHER SOUTH...THE DRY SLOT WILL MAKE IT DIFFICULT FOR ICE
CRYSTALS TO GET INTRODUCED INTO THE CLOUD...SO HAVE ADDED THE CHANCE
OF FREEZING DRIZZLE OVER CENTRAL AND PARTS OF NORTHEAST WISCONSIN.
RAIN OR DRIZZLE SHOULD BE MIXING WITH SNOW BY THE TIME OF THE
MORNING COMMUTE OVER THE FOX VALLEY AND LAKESHORE WHICH LOOKS TO BE
A SLOPPY MESS. SHOULD ALSO SEE A PERIOD OF OF JUST RAIN/DRIZZLE AS
WELL...MID-MORNING THROUGH MID-AFTERNOON BEFORE COLDER AIR SURGES
EAST AS IT WRAPS AROUND THE LOW. WITH ALL THIS IN MIND...TOTAL
SNOWFALL ACCUMULATION THROUGH 00Z THU LOOKS LIKE 10-15 INCHES OVER
N-C WISCONSIN...6-10 NORTH OF A MARSHFIELD TO STURGEON BAY
LINE...AND 3-7 INCHES FOR CENTRAL WISCONSIN AND MUCH OF THE FOX
VALLEY. DID END HEADLINES EARLY FOR THE FOX VALLEY AND
LAKESHORE...AS SNOW CHANGING TO RAIN SHOULD CAUSE CONDITIONS TO
RAPIDLY IMPROVE BY 18Z WED.
LONG TERM...WEDNESDAY NIGHT THROUGH NEXT TUESDAY.
PERIOD TO SEE SHIFT FROM OUR SPLIT FLOW PATTERN TO A MORE
CONSOLIDATED FLOW WITH TROF SHIFTING EAST THROUGH THE LAKES REGION
THIS WEEKEND. TEMPS FOR SAT AND SUN EXPECTED TO BE AOB NORMS. RIDGE
TO FOLLOW FOR MUCH OF THE WORK WEEK FOR A DRY AND MILD PERIOD.
WED NIGHT TO THU...STORM TO BE EXITING THE AREA WITH SNOW ENDING
WEST TO EAST. LEFT OUT OF GRIDS AT THIS TIME...THOUGH MODEL
SOUNDINGS INDICATE SOME FREEZING DRIZZLE POSSIBLE OVER THE EAST
BEHIND SYSTEM. WEAK HIGH PRESSURE MOVES THROUGH DURING DAY
THU...SMALL CHANCE OF LAKE EFFECT FAR NW VILAS IN THE MORNING
THOUGH SUPPORT FOR THAT WEAKENS BY AFTERNOON.
THU NIGHT TO FRIDAY...MODELS STILL HAVING DIFFICULTY THIS
PERIOD...THOUGH STARTING TO GEL A BIT. TROF OF LOW
PRESSURE/DEVELOPING COLD FRONT MOVES EAST INTO STATE LATE THU
NIGHT. SIG WAA AHEAD OF SYSTEM AND SOME FGEN SAYS KEEP SMALL
POPS...MAINLY NORTH...UPPER SUPPORT WEAK THOUGH. ALL MODELS WANT TO
DEVELOP WAVE ON FRONT SOUTH OF STATE...BRING IT NE ALONG FRONT.
MOST TO OUR EAST...THOUGH GFS REMAINS CONSISTENT BRINGING LOW
THROUGH STATE. EITHER WAY KEPT CHANCE POPS HIGHEST EAST. SOME
CONCERN WITH PCPN TYPE...WILL GO FOR MIX EAST...THOUGH LATEST EC
BRINGING COLDER AIR FURTHER EAST.
WEEKEND...HINTS AT POSSIBLE CLIPPER SYSTEM SUN...AND POSSIBLE
LAKE EFFECT FAR NORTHWEST CWA WITH NORTHWEST FLOW.
&&
.AVIATION...MAINLY IFR TO LIFR CONDITIONS DUE TO HEAVY SNOW ACROSS
NORTHERN WISCONSIN TODAY...BEFORE GRADUALLY IMPROVING TO MVFR
CONDITIONS THROUGH. AREAS ROUGHLY SOUTH OF A LINE FROM AUW TO SUE
CAN EXPECT MAINLY MVFR CIGS AND VSBYS DUE TO SNOW/SLEET/FREEZING
RAIN AND RAIN TODAY BEFORE CHANGING BACK TO ALL LIGHT SNOW TONIGHT
WITH MVFR CONDITIONS.
TDH
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL NOON CST WEDNESDAY FOR WIZ038>040-
048>050.
WINTER WEATHER ADVISORY UNTIL 6 PM CST WEDNESDAY FOR WIZ035>037-
045.
WINTER STORM WARNING UNTIL 6 PM CST WEDNESDAY FOR WIZ005-010>013-
018>021-030-031-073-074.
WINTER STORM WARNING UNTIL NOON CST WEDNESDAY FOR WIZ022.
&&
$$
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1003 PM CST TUE FEB 28 2012
.UPDATE...WINTER STORM MOVING ALONG MORE OR LESS AS EARLIER
FORECAST. SURFACE LOW IS A BIT FURTHER SOUTH THAN THE 12Z MODELS
DEPCITED WITH BEST PRESSURE FALLS AT 03Z SUGGESTING IT WILL MOVE
TOWARDS LA CROSSE BY NOON TOMORROW. NAM FORECAST SOUNDINGS
VERIFIED BEST AGAINTS THE 00Z GRB AND MPX RADIOSONDES. IF THESE
FORECAST SOUNDINGS FOR OUR FORECAST AREA ARE ACCURATE THEN OUR
CURRENT ADVISORIES AND WARNINGS ARE WELL PLACED. SOME CONCERN THAT
WOOD, PORTAGE AND WAUPACA COUNTIES COULD GET MORE THAN SIX INCHES
OF SNOW IF IT STAYS SNOW THROUGH MOST OF THE NIGHT BUT ALL OF THE
MODELS BRING AN ELEVATED ABOVE FREEZING LAYER AROUND 850MB ACROSS
THAT AREA BY 06Z OR SO WHICH WOULD CHANGE THE SNOW OVER TO SLEET
OR FREEZING RAIN. DRY AIR NEAR THE LAKE MICHIGAN SHORE IS DELAYING
ARRIVAL OF PRECIPITATION BUT IT WILL GET THERE. SNOW WAS FALLING
OVER ALL OF THE AREA WITH THE EXCEPTION OF SOUTHERN WINNEBAGO
COUNTY WHERE IS WAS RAINING AND PARTS OF CALUMET COUNTY WHERE SOME
LIGHT FREEZING RAIN WAS REPORTED.
RDM
&&
.PREV DISCUSSION...ISSUED AT 644 PM CST TUE FEB 28 2012...
SHORT TERM...TONIGHT AND WEDNESDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY INDICATES LOW
PRESSURE EMERGING FROM THE ROCKIES INTO WESTERN KANSAS THIS AFTERNOON...WITH
ITS ASSOCIATED WARM FRONT LIFTING NORTH ALONG THE KS/NE BORDER AND
ACROSS MISSOURI. CONVECTION HAS DEVELOPED ALREADY AHEAD OF THE LOW
JUST AHEAD OF A POTENT DRY SLOT PUNCHING INTO NEBRASKA. CLOSER TO
HOME...LEADING EDGE OF RETURN MOISTURE IS NOW PUSHING INTO SOUTHERN
WISCONSIN A TAD AHEAD OF SCHEDULE...AS EVIDENT BY A BAND OF RAIN AND
SNOW. EARLIER MODERATE SNOW OVER N-C WISCONSIN IS HANGING ON ALONG
THE U.P. BORDER WHERE THEY RECEIVED 2-3 INCHES OF SNOW. BUT THE
MAIN PROBLEM FOR THIS FORECAST IS THE LOW OUT WEST AND HEAVY SNOW
POTENTIAL AS IT MOVES ACROSS THE REGION TONIGHT INTO WEDNESDAY.
TONIGHT...LOW PRESSURE OVER THE PLAINS WILL MOVE NORTHEAST AND
OCCLUDE AS IT MOVES INTO SOUTHWEST MINNESOTA BY 12Z WEDNESDAY.
AHEAD OF THE LOW...A 40-50KT LLJ WILL RAMP UP AND SHIFT INTO
NORTHERN ILLINOIS DURING THE OVERNIGHT HOURS. THIS LLJ WILL
TRANSPORT RICH GULF OF MEXICO MOISTURE NORTHEAST WITH PWATS OF
UPWARDS OF 0.75 INCHES REACHING INTO CENTRAL WISCONSIN. THIS IS
OVER 200 PCT OF NORMAL AND 2 STANDARD DEVIATIONS ABOVE NORMAL.
BEFORE THIS OCCURS THOUGH...LEADING EDGE OF THE RETURN MOISTURE ON
THE 285K SURFACE IS CREATING A BAND OF LIGHT RAIN AND SNOW WHICH
SHOULD APPROACH CENTRAL WISCONSIN LATE THIS AFTERNOON AND INTO THE
FOX VALLEY BY EARLY IN THE EVENING. WET BULB TEMPS HAVE BEEN RISING
THIS AFTERNOON...BUT FIGURING SNOW OVER CENTRAL WISCONSIN...AND
RAIN/SNOW MIX OVER EAST-CENTRAL WHERE ONSHORE FLOW WILL CONTINUE.
THE MAIN SURGE OF PRECIPITATION SHOULD NOT ARRIVE UNTIL LATE INTO
THE EVENING AND THE OVERNIGHT HOURS WHEN FORCING VIA LLJ AND
MID-LEVEL FGEN LIFTS INTO THE REGION. WITH MID-LEVEL LAPSE RATES OF
6.5-7 C/KM AND NEGATIVE EPV ABOVE THE FGEN LAYER...CONVECTION IS
DEFINITELY POSSIBLE WITH THE PRECIPITATION OVERNIGHT...AND UPSTREAM
OBS BEAR THIS OUT AS WELL. THERMAL PROFILES VARY WIDELY BETWEEN THE
WARMER GFS AND THE COLDER ECMWF/NAM. ALTHOUGH THERE IS PLENTY OF
WARM AIR TO OUR SOUTH...THE WARM LAYER IS MARGINALLY HIGH AT AROUND
800MB WHICH LEAVES THE POTENTIAL FOR CONVECTION TO WIPE OUT THAT
WARM NOSE...THEREBY KEEPING THE PROFILE NEAR OR JUST BELOW FREEZING
OVER CENTRAL AND EAST-CENTRAL WISCONSIN. AS A RESULT...HAVE BOOSTED
SNOW AMOUNTS OVER CENTRAL WISCONSIN AND THE NORTHERN FOX VALLEY. AM
MOST CONFIDENT OF RAIN/SLEET MIXING IN OVER KEWAUNEE AND MANITOWOC
COUNTIES THANKS TO THE LAKE INFLUENCE. SE WINDS WILL ALSO RAMP UP
OVERNIGHT WHICH COULD CREATE NEAR WHITE OUT VSBYS AT TIMES WITHIN
THE HEAVY SNOW. WILL UPGRADE DOOR COUNTY TO WARNING CRITERIA...AS
THEY DO SURPRISINGLY WELL IN CASES LIKE THIS...WHERE COLDER AIR AT
925MB WILL HANG ON THE LONGEST. OTHERWISE...CURRENT HEADLINES LOOK
GOOD FOR WARNING/ADVISORY CONFIGURATION. THE NEXT SHIFT WILL HAVE
TO MONITOR FOR UPGRADES FOR THE NEXT ROW OF COUNTIES SOUTH OF THE
WARNING IF CONVECTION DOES COOL THE COLUMN ENOUGH FOR A MOSTLY SNOW
PTYPE.
WEDNESDAY...OCCLUDED LOW PRESSURE WILL SLOW AND MOVE FROM SW
MINNESOTA TO WESTERN WISCONSIN OVER THE COURSE OF THE DAY. LOW
LEVEL WARM AIR WILL CONTINUE TO WRAP AROUND THE LOW INTO EASTERN
WISCONSIN DURING THE MORNING...WHILE THE DRY SLOW MOVES IN ALOFT.
MODERATE TO HEAVY SNOW WILL BE WIDESPREAD NORTH AND WEST OF THE DRY
SLOT OVER NORTHERN AND NORTHWEST WISCONSIN FOR MUCH OF THE MORNING.
BUT FARTHER SOUTH...THE DRY SLOT WILL MAKE IT DIFFICULT FOR ICE
CRYSTALS TO GET INTRODUCED INTO THE CLOUD...SO HAVE ADDED THE CHANCE
OF FREEZING DRIZZLE OVER CENTRAL AND PARTS OF NORTHEAST WISCONSIN.
RAIN OR DRIZZLE SHOULD BE MIXING WITH SNOW BY THE TIME OF THE
MORNING COMMUTE OVER THE FOX VALLEY AND LAKESHORE WHICH LOOKS TO BE
A SLOPPY MESS. SHOULD ALSO SEE A PERIOD OF OF JUST RAIN/DRIZZLE AS
WELL...MID-MORNING THROUGH MID-AFTERNOON BEFORE COLDER AIR SURGES
EAST AS IT WRAPS AROUND THE LOW. WITH ALL THIS IN MIND...TOTAL
SNOWFALL ACCUMULATION THROUGH 00Z THU LOOKS LIKE 10-15 INCHES OVER
N-C WISCONSIN...6-10 NORTH OF A MARSHFIELD TO STURGEON BAY
LINE...AND 3-7 INCHES FOR CENTRAL WISCONSIN AND MUCH OF THE FOX
VALLEY. DID END HEADLINES EARLY FOR THE FOX VALLEY AND
LAKESHORE...AS SNOW CHANGING TO RAIN SHOULD CAUSE CONDITIONS TO
RAPIDLY IMPROVE BY 18Z WED.
LONG TERM...WEDNESDAY NIGHT THROUGH NEXT TUESDAY.
PERIOD TO SEE SHIFT FROM OUR SPLIT FLOW PATTERN TO A MORE
CONSOLIDATED FLOW WITH TROF SHIFTING EAST THROUGH THE LAKES REGION
THIS WEEKEND. TEMPS FOR SAT AND SUN EXPECTED TO BE AOB NORMS. RIDGE
TO FOLLOW FOR MUCH OF THE WORK WEEK FOR A DRY AND MILD PERIOD.
WED NIGHT TO THU...STORM TO BE EXITING THE AREA WITH SNOW ENDING
WEST TO EAST. LEFT OUT OF GRIDS AT THIS TIME...THOUGH MODEL
SOUNDINGS INDICATE SOME FREEZING DRIZZLE POSSIBLE OVER THE EAST
BEHIND SYSTEM. WEAK HIGH PRESSURE MOVES THROUGH DURING DAY
THU...SMALL CHANCE OF LAKE EFFECT FAR NW VILAS IN THE MORNING
THOUGH SUPPORT FOR THAT WEAKENS BY AFTERNOON.
THU NIGHT TO FRIDAY...MODELS STILL HAVING DIFFICULTY THIS
PERIOD...THOUGH STARTING TO GEL A BIT. TROF OF LOW
PRESSURE/DEVELOPING COLD FRONT MOVES EAST INTO STATE LATE THU
NIGHT. SIG WAA AHEAD OF SYSTEM AND SOME FGEN SAYS KEEP SMALL
POPS...MAINLY NORTH...UPPER SUPPORT WEAK THOUGH. ALL MODELS WANT TO
DEVELOP WAVE ON FRONT SOUTH OF STATE...BRING IT NE ALONG FRONT.
MOST TO OUR EAST...THOUGH GFS REMAINS CONSISTENT BRINGING LOW
THROUGH STATE. EITHER WAY KEPT CHANCE POPS HIGHEST EAST. SOME
CONCERN WITH PCPN TYPE...WILL GO FOR MIX EAST...THOUGH LATEST EC
BRINGING COLDER AIR FURTHER EAST.
WEEKEND...HINTS AT POSSIBLE CLIPPER SYSTEM SUN...AND POSSIBLE
LAKE EFFECT FAR NORTHWEST CWA WITH NORTHWEST FLOW.
&&
.AVIATION...CONDITIONS WILL FALL TO IFR FROM WEST TO EAST THIS
EVENING AS WINTER STORM APPROACHES FROM THE CENTRAL PLAINS. MOSTLY
SNOW EXPECTED OVERNIGHT NORTH OF A WAUSAU TO STURGEON BAY LINE
WITH A MIXTURE OF SNOW...SLEET AND FREEZING RAIN FURTHER SOUTH.
SNOW ILL CONTINUE WEDNESDAY NORTH OF RHINELANDER WITH SCATTERED
LIGHT RAIN OR DRIZZLE FURTHER SOUTH. CIGS MAY FALL TO NEAR
AIRFIELD MINIMUMS LATE TONIGHT AND WEDNESDAY.
RDM
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL NOON CST WEDNESDAY FOR WIZ038>040-
048>050.
WINTER WEATHER ADVISORY UNTIL 6 PM CST WEDNESDAY FOR WIZ035>037-
045.
WINTER STORM WARNING UNTIL 6 PM CST WEDNESDAY FOR WIZ005-010>013-
018>021-030-031-073-074.
WINTER STORM WARNING UNTIL NOON CST WEDNESDAY FOR WIZ022.
&&
$$
AREA FORECAST DISCUSSION...UPDATED FOR AVIATION
NWS LITTLE ROCK AR
1140 PM CST THU MAR 1 2012
.AVIATION...02/06Z TAF CYCLE
LOW CLOUDS WILL CONTNIUE TO DEVELOP AND ADVECT NORTHWARD
INTO THE AREA OVERNIGHT. VFR CEILINGS WILL EVENTUALLY LOWER
TO MVFR LEVELS...WITH OCCASIONAL IFR CEILINGS TOWARD SUNRISE. CANNOT
RULE OUT ISOLATED THUNDERSTORMS OVERNIGHT...ESPECIALLY IN THE
NORTHERN HALF OF THE STATE.
A STRONG STORM SYSTEM WILL PASS TO THE NORTH OF ARKANSAS ON FRIDAY...
AND WILL DRAG A COLD FRONT THROUGH THE STATE. THE FRONT WILL LIKELY
TRIGGER THUNDERSTORMS IN THE AFTERNOON...WITH THE BEXT CHANCES OF
PRECIPITATION ALONG AND EAST OF THE MISSISSIPPI RIVER.
SOUTHERLY WINDS THROUGH FRIDAY MORNING WILL GRADUALLY BECOME
SOUTHWEST AND THEN WEST/NORTHWEST LATER IN THE DAY. WINDS ON FRIDAY
WILL BE STRONG/GUSTY...WITH GUSTS FROM 30 TO 40 MPH. VFR CONDITIONS
WILL RETURN FRIDAY AFTERNOON AND EVENING AS HIGH PRESSURE BUILDS
INTO THE REGION BEHIND THE FRONT.
&&
.UPDATE...
HAVE MADE SOME FAIRLY NOTABLE CHANGES TO OVERNIGHT POPS AND CLOUD
COVER. LATEST HIGH RESOLUTION WRF...AND RAPID UPDATE RUC MODEL
RUNS SHOW VERY LITTLE SHOWER ACTIVITY OVERNIGHT. AS SUCH...REMOVED
MENTION OF PRECIP THROUGH MIDNIGHT...AND LIMITED POPS TO SLIGHT
CHANCE IN THE NORTH ONLY THROUGH ROUGHLY DAYBREAK. ANY SHOWERS
WILL PROBABLY BE CONFINED TO THE NORTH WHERE LARGE SCALE ASCENT IS
A LITTLE MORE PRONOUNCED LATE TONIGHT AND EARLY FRIDAY MORNING.
ALSO ADJUSTED CLOUD COVER TO ACCOUNT FOR RECENT TRENDS.
OTHERWISE...FORECAST WAS IN GOOD SHAPE OVERALL AND DID NOT MAKE
ANY OTHER SIGNIFICANT CHANGES.
&&
.PREV DISCUSSION... /ISSUED 228 PM CST THU MAR 1 2012/
SHORT TERM...TONIGHT THROUGH SUNDAY NIGHT
MOISTURE SURGE WILL GRADUALLY LIFT NORTHWARD TONIGHT...AS A WARM
FRONT ADVANCES INTO ARKANSAS. WEAK WAVE ALOFT MOVING THROUGH LATER
TONIGHT WILL INTERACT WITH THE ADVANCING FRONT...WITH SCATTERED
SHOWERS/STORMS POSSIBLE ALONG AND NORTH OF THE BOUNDARY. ANY
STORMS SHOULD MOSTLY BE NORTH OF INTERSTATE 40. SOME STRONG STORMS
ARE POSSIBLE...MAINLY AFTER MIDNIGHT...AND THE PRIMARY THREAT WITH
ANY STRONG STORMS WOULD BE LARGE HAIL. HOWEVER...INSTABILITY IS
WEAK...SO AM THINKING STRONG STORMS WOULD BE ISOLATED AT BEST.
AFTER THE INITIAL MOISTURE SURGE...LOW PRESSURE WILL BRING A COLD
FRONT INTO THE REGION DURING THE DAY FRIDAY. SHOWERS/STORMS WILL
BE POSSIBLE AHEAD OF THE FRONT...MAINLY ACROSS THE EASTERN HALF OF
THE STATE. AGAIN...SOME STORMS COULD BE STRONG...BUT I/M THINKING
THAT THE GREATEST SEVERE THREAT WILL BE EAST OF THE FORECAST AREA.
COLD HIGH PRESSURE WILL MOVE IN BEHIND THE FRONT...WITH READINGS
10-20 DEGREES COOLER BY SATURDAY. THE HIGH WILL SHIFT EASTWARD BY
LATE SUNDAY...WITH TEMPERATURES BEGINNING TO WARM.
LONG TERM...MONDAY THROUGH THURSDAY
SFC HIGH PRESSURE JUST OFF TO THE EAST OF THE STATE WILL PROVIDE AR
DRY WX...SRLY FLOW...AND ABOVE NORMAL TEMPERATURES FROM MON THROUGH
WED. AN UPR RIDGE WILL AT THE SAME TIME MOVE SLOWLY ACROSS THE SRN
PLAINS. AS THIS UPR RIDGE CONTS TO SLOWLY MOVE EAST...A PAIR OF
SHRTWVS WILL BEGIN TO AFFECT AR...THE FIRST A NRN STREAM ONE AND THE
SECOND A SRN STREAM ONE.
THE ECMWF ALLOWS THE NRN STREAM WAVE TO PUSH A SFC COLD FRONT INTO
NRN AR THU WITH PRECIP ALONG AND AHEAD OF IT. THE GFS IS WEAKER AND
FURTHER NORTH WITH THIS SHRTWV...CAUSING THE FRONT TO STALL FURTHER
NORTH. WILL CONTINUE TO HEDGE TOWARD THE STRONGLY PERFORMING ECWMF
AND LEAVE CHC POPS IN NRN AR THU AND THU NIGHT. WILL TRIM POP CHCS
BACK TO SLIGHT OVER THE REST OF THE STATE IN THIS PD. THE SECOND...
SRN STREAM SHRTWV WILL HOLD OFF UNTIL NEXT WEEKEND...AFTER THE END
OF THE FCST PD.
&&
.PRELIMINARY POINT TEMPS/POPS...
BATESVILLE AR 73 60 70 35 / 0 40 50 10
CAMDEN AR 82 62 79 42 / 10 20 20 20
HARRISON AR 73 60 64 32 / 0 40 50 10
HOT SPRINGS AR 80 63 75 39 / 10 20 20 10
LITTLE ROCK AR 80 63 78 40 / 10 30 30 20
MONTICELLO AR 80 65 80 44 / 10 30 50 50
MOUNT IDA AR 78 63 72 37 / 10 10 20 10
MOUNTAIN HOME AR 75 58 67 33 / 0 50 50 10
NEWPORT AR 72 59 70 37 / 0 50 50 20
PINE BLUFF AR 79 63 78 43 / 10 30 30 30
RUSSELLVILLE AR 80 57 75 34 / 0 20 30 10
SEARCY AR 75 61 73 37 / 0 40 40 20
STUTTGART AR 79 63 78 41 / 10 30 40 30
&&
.LZK WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LITTLE ROCK AR
1003 PM CST THU MAR 1 2012
.UPDATE...
HAVE MADE SOME FAIRLY NOTABLE CHANGES TO OVERNIGHT POPS AND CLOUD
COVER. LATEST HIGH RESOLUTION WRF...AND RAPID UPDATE RUC MODEL
RUNS SHOW VERY LITTLE SHOWER ACTIVITY OVERNIGHT. AS SUCH...REMOVED
MENTION OF PRECIP THROUGH MIDNIGHT...AND LIMITED POPS TO SLIGHT
CHANCE IN THE NORTH ONLY THROUGH ROUGHLY DAYBREAK. ANY SHOWERS
WILL PROBABLY BE CONFINED TO THE NORTH WHERE LARGE SCALE ASCENT IS
A LITTLE MORE PRONOUNCED LATE TONIGHT AND EARLY FRIDAY MORNING.
ALSO ADJUSTED CLOUD COVER TO ACCOUNT FOR RECENT TRENDS.
OTHERWISE...FORECAST WAS IN GOOD SHAPE OVERALL AND DID NOT MAKE
ANY OTHER SIGNIFICANT CHANGES.
&&
.PREV DISCUSSION... /ISSUED 555 PM CST THU MAR 1 2012/
AVIATION...02/00Z TAF CYCLE
VFR CONDS WL START OF THE PD...BUT LOW LVL MOISTURE WL INCRS DURG
THE OVERNIGHT HRS WITH MVFR CIGS DVLPG ACRS THE FA. WARM FNT IS
ALSO FCST TO LIFT NWD ACRS THE AREA LATER TNGT...WITH A CHC OF
CONVECTION DVLPG...MAINLY OVR NRN AR. SFC LOW WL PASS N OF THE
AREA ON FRI WITH A CDFNT PASSING EWD ACRS AR. BEST CHCS OF
ORGANIZED CONVECTION STILL LOOK TO BE ALONG AND E OF THE MS RVR.
INCRSG SW/WLY WINDS WL BRING DRIER AIR AND IMPROVING CONDS TO AR
BY FRI AFTN. /44/
PREV DISCUSSION... /ISSUED 228 PM CST THU MAR 1 2012/
SHORT TERM...TONIGHT THROUGH SUNDAY NIGHT
MOISTURE SURGE WILL GRADUALLY LIFT NORTHWARD TONIGHT...AS A WARM
FRONT ADVANCES INTO ARKANSAS. WEAK WAVE ALOFT MOVING THROUGH LATER
TONIGHT WILL INTERACT WITH THE ADVANCING FRONT...WITH SCATTERED
SHOWERS/STORMS POSSIBLE ALONG AND NORTH OF THE BOUNDARY. ANY
STORMS SHOULD MOSTLY BE NORTH OF INTERSTATE 40. SOME STRONG STORMS
ARE POSSIBLE...MAINLY AFTER MIDNIGHT...AND THE PRIMARY THREAT WITH
ANY STRONG STORMS WOULD BE LARGE HAIL. HOWEVER...INSTABILITY IS WEAK...
SO AM THINKING STRONG STORMS WOULD BE ISOLATED AT BEST.
AFTER THE INITIAL MOISTURE SURGE...LOW PRESSURE WILL BRING A COLD
FRONT INTO THE REGION DURING THE DAY FRIDAY. SHOWERS/STORMS WILL
BE POSSIBLE AHEAD OF THE FRONT...MAINLY ACROSS THE EASTERN HALF OF
THE STATE. AGAIN...SOME STORMS COULD BE STRONG...BUT I/M THINKING
THAT THE GREATEST SEVERE THREAT WILL BE EAST OF THE FORECAST AREA.
COLD HIGH PRESSURE WILL MOVE IN BEHIND THE FRONT...WITH READINGS
10-20 DEGREES COOLER BY SATURDAY. THE HIGH WILL SHIFT EASTWARD BY
LATE SUNDAY...WITH TEMPERATURES BEGINNING TO WARM.
LONG TERM...MONDAY THROUGH THURSDAY
SFC HIGH PRESSURE JUST OFF TO THE EAST OF THE STATE WILL PROVIDE AR
DRY WX...SRLY FLOW...AND ABOVE NORMAL TEMPERATURES FROM MON THROUGH
WED. AN UPR RIDGE WILL AT THE SAME TIME MOVE SLOWLY ACROSS THE SRN
PLAINS. AS THIS UPR RIDGE CONTS TO SLOWLY MOVE EAST...A PAIR OF
SHRTWVS WILL BEGIN TO AFFECT AR...THE FIRST A NRN STREAM ONE AND THE
SECOND A SRN STREAM ONE.
THE ECMWF ALLOWS THE NRN STREAM WAVE TO PUSH A SFC COLD FRONT INTO
NRN AR THU WITH PRECIP ALONG AND AHEAD OF IT. THE GFS IS WEAKER AND
FURTHER NORTH WITH THIS SHRTWV...CAUSING THE FRONT TO STALL FURTHER
NORTH. WILL CONTINUE TO HEDGE TOWARD THE STRONGLY PERFORMING ECWMF
AND LEAVE CHC POPS IN NRN AR THU AND THU NIGHT. WILL TRIM POP CHCS
BACK TO SLIGHT OVER THE REST OF THE STATE IN THIS PD. THE SECOND...
SRN STREAM SHRTWV WILL HOLD OFF UNTIL NEXT WEEKEND...AFTER THE END
OF THE FCST PD.
&&
.PRELIMINARY POINT TEMPS/POPS...
BATESVILLE AR 73 60 70 35 / 0 40 50 10
CAMDEN AR 82 62 79 42 / 10 20 20 20
HARRISON AR 73 60 64 32 / 0 40 50 10
HOT SPRINGS AR 80 63 75 39 / 10 20 20 10
LITTLE ROCK AR 80 63 78 40 / 10 30 30 20
MONTICELLO AR 80 65 80 44 / 10 30 50 50
MOUNT IDA AR 78 63 72 37 / 10 10 20 10
MOUNTAIN HOME AR 75 58 67 33 / 0 50 50 10
NEWPORT AR 72 59 70 37 / 0 50 50 20
PINE BLUFF AR 79 63 78 43 / 10 30 30 30
RUSSELLVILLE AR 80 57 75 34 / 0 20 30 10
SEARCY AR 75 61 73 37 / 0 40 40 20
STUTTGART AR 79 63 78 41 / 10 30 40 30
&&
.LZK WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
AVIATION...99
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1003 PM MST THU MAR 1 2012
CORRECTED WATCH/WARNING/ADVISORY LINE
.UPDATE...CONVECTIVE SHOWERS ARE GRADUALLY DISSIPATING...ALTHOUGH
EXPECT A LITTLE REGENERATION FROM DENVER SOUTHWARD TO MORE
NORTHERLY FLOW. MOST PLACE WILL SEE LESS THAN AN INCH OVERNIGHT.
&&
.AVIATION...A FEW SNOW SHOWERS HAVE FINALLY DEVELOPED IN THE
IMMEDIATE DENVER METRO AREA...AND SHOULD MAINLY IMPACT KAPA WITH
THE MAIN SHOT OF SNOW THROUGH 08Z. MAYBE AN INCH IN THAT AREA BUT
LITTLE IF ANY ACCUMULATION AT KDEN AND KBJC OVERNIGHT. STILL A
THREAT OF 1-2 INCHES TOMORROW IF WINDS CAN TURN SLIGHTLY INTO THE
FOOTHILLS.
&&
.PREV DISCUSSION... /ISSUED 659 PM MST THU MAR 1 2012/
UPDATE...CONVECTION IS MAKING FOR A DIFFICULT FORECAST
TONIGHT...AND SIMILAR DIFFICULTY ALL THE WAY THROUGH FRIDAY.
LATEST SURFACE ANALYSIS SHOWS A STRONG ANTICYCLONE ACROSS
NORTHEAST COLORADO. THIS HAS BROUGHT DOWNSLOPING SOUTHEAST WINDS
TO DENVER...WHILE RATHER STRONG LOW LEVEL CONVERGENCE HAS
DEVELOPED IN THE FORT COLLINS TO NORTHERN WELD COUNTY AREA WHERE
CONVECTION HAS BLOSSOMED IN THE LAST HOUR. POCKETS OF 25-35 DBZ
ECHOES LIKELY RESULTING IN POCKETS OF HEAVY SNOW WITH AT LEAST 1
INCH PER HOUR RATES. QUESTION IS HOW THIS EVOLVES OVERNIGHT...AND
LATEST MESOSCALE MODELS INCLUDING THE ARW AND NMM SHOW THIS
PUSHING SOUTHEAST IN SIMILAR FASHION TO THE NAM. MEANWHILE...RUC13
AND HRRR HAD NO CLUE WHERE SNOW IS EVEN OCCURRING AT THE PRESENT
TIME. FEEL THE LATEST 4KM WRF MIGHT HAVE THE BETTER HANDLE ON IT
CONSIDERING THE LATEST SURFACE ANALYSIS...KEEPING THE HEAVIEST
SNOW IN LARIMER AND WELD COUNTIES BEFORE WEAKENING AS IT SPREADS
SOUTHEAST TO THE DENVER METRO AREA. THERE IS A LOT OF UNCERTAINTY
WITH THIS FORECAST...BUT ANYWHERE CONVECTION IS MORE PERSISTENT
COULD REQUIRE AN ADVISORY. WE WILL HAVE TO MONITOR THROUGH THE
REST OF THE NIGHT. BAND OF SNOW OR REDEVELOPMENT OF CONVECTION IS
FAIRLY LIKELY BEHIND THE NEXT COLD FRONT DROPPING SOUTHWARD ACROSS
THE PLAINS AROUND DAYBREAK FRIDAY...SO CONVECTIVE SNOW MAY
REDEVELOP WITH EVEN SOME CAPE NOTED ON FORECAST SOUNDINGS. MIGHT
HAVE TO ISSUE AN ADVISORY FOR DENVER METRO FOR THE DAY FRIDAY IF
WINDS CAN TURN INTO THE HILLS JUST ENOUGH. PALMER DIVIDE AND
SOUTHERN FOOTHILLS ARE STILL SETTING UP THE BEST.
AVIATION...CONVECTIVE SNOW SHOWERS TO THE NORTHWEST OF THE DENVER
METRO AREA AIRPORTS WILL HAVE TO BE WATCHED. AT THE CURRENT
TIME...WE DO THINK THESE SHOWERS WILL GRADUALLY WEAKEN AS THEY
PUSH TOWARD KDEN...KBJC...AND KAPA BY 03Z-06Z...BUT IFR/LIFR
CONDITIONS WOULD BE POSSIBLE WITH A QUICK INCH OF ACCUMULATION.
REST OF FORECAST UNCHANGED WITH POTENTIAL FOR MORE WIDESPREAD SNOW
FRIDAY MORNING.
PREV DISCUSSION... /ISSUED 503 PM MST THU MAR 1 2012/
UPDATE...SNOW HAS NOT MATERIALIZED ACROSS URBAN CORRIDOR AS
PREVIOUSLY THOUGHT. AFTER THE INCREASE IN UPSLOPE EARLIER THIS
AFTERNOON...THE UPSLOPE HAS WEAKEND OR BECOME NON EXISTANT AND
ECHOES HAVE MOSTLY DISSIPATED. STILL SOME ECHOES ACROSS PALMER
DIVIDE HEADING INTO LINCOLN COUNTY. SNOW SHOWERS STILL POSSIBLE
THROUGH TONIGHT...MAINLY THIS EVENING QG ASCENT MOVES ACROSS THE
REGION. BUT THESE SHOWERS WILL MAINLY BE LIGHT ACROSS THE
PLAINS...WITH LITTLE OR NO IMPACT. BEST CHANCE FOR THESE SHOWERS
STILL LOOK TO BE ALONG THE PALMER DIVIDE AND SOUTHERN FOOTHILLS.
SO MAIN CHANGE FOR THIS UPDATE WILL BE TO DROP ADVISORY FOR ZONES
39 AND 40...DECREASE POPS AND SNOW AMOUNTS. NOW LOOKS LIKE BEST
CHANCE OF ACCUMULATING SNOW SHIFTING TOWARD THE MORNING HOURS
FRIDAY BEHIND SURFACE FRONT. HILITES FOR MOUNTAINS STILL LOOK ON
TRACK
AVIATION...SNOW CHANCES ACROSS AREA THIS EVENING HAVE DECREASED.
AS A RESULT...VFR CONDITIONS TO PREVAIL WITH A CHANCE FOR MVFR
BETWEEN 02Z AND 05Z WITH PASSING SNOW SHOWERS. NEXT WAVE STILL
EXPECTED TO AFFECT AREA IN THE 10Z TO 16Z TIME FRAME WITH A BETTER
CHANCE FOR SNOWFALL AND MVFR CONDITIONS.
PREV DISCUSSION... /ISSUED 341 PM MST THU MAR 1 2012/
SHORT TERM...MOIST NORTHWEST FLOW ALOFT CONTINUES ACROSS THE
REGION THROUGH FRIDAY. AFTER A BRIEF DECREASE IN MOUNTAIN
SNOW...WEB CAMS AS WELL AS RADAR SHOW THE SNOW HAS INCREASED
AGAIN. WATER VAPOR LOOPS SHOW SOME SORT OF SHORTWAVE MOVING INTO
WESTERN COLORADO WHICH MAY BE AIDING IN THE SNOW INCREASE. THE
MOUNTAIN WARNINGS AND ADVISORIES STILL WARRANTED THROUGH TONIGHT.
THOUGH THERE MAY BE A BIT OF A DECREASE AGAIN OVERNIGHT AS SHOWN
BY THE LATEST RUC AND HRR RUNS. AS FOR PLAINS... STILL A BIT OF A
TRICKY FORECAST THIS EVENING AS MOST MODELS NOT HANDLING THINGS
WELL IN THE SHORT TERM. AIRMASS STILL A BIT UNSTABLE AND LOCAL
ACARS SOUNDINGS HAVE SHOWN A DEEPENING UPSLOPE. EARLIER SNOWBAND
HAS HELPED TO MOISTEN THE LOWER LAYERS. RADAR SHOWING ECHOES ALONG
FOOTHILLS AND URBAN CORRIDOR AS FAR NORTH AS LARIMER COUNTY...WITH
MOST OF THE ACTIVITY OVER JEFFERSON AND DOUGLAS COUNTIES. SO MOST
AREAS IN AND NEAR URBAN CORRIDOR SHOULD SEE SNOW SOON. AS
TEMPERATURES GET COLDER THIS EVENING...SHOULD ALSO SEE SOME
ACCUMULATING SNOW. ADVISORY FOR SOUTHERN FOOTHILLS AND PORTIONS OF
URBAN CORRIDOR STILL LOOKING ON TRACK. SHOULD SEE SOME BREAK IN
THE SNOWFALL TOWARDS 06Z...BASED ON THOSE RUC AND HRR RUNS. NEXT
WAVE LOOKS TO MOVE INTO THE AREA SATURDAY MORNING WHICH SHOULD
INCREASE THE SNOWFALL ACROSS THE REGION. WARNING AND ADVISORIES
FOR THE MOUNTAINS CONTINUE THROUGH FRIDAY...LOOKS REASONABLE. AS
FOR PLAINS...BEST CHANCE FOR SNOW TO BE IN THE 10Z-16Z AS THE LIFT
COMBINES WITH NORTHERLY FLOW...WITH THE BEST AREA IN ZONES 36 AND
41. FLOW BECOMES NORTHWEST DURING THE AFTERNOON...WITH DRIER AIR
WORKING ACROSS THE AREA. SHOULD SEE A DECREASE IN SNOW BY THE
AFTERNOON. OVERALL...CURRENT SNOW AMOUNTS STILL LOOK ON TRACK.
LONG TERM...BY FRIDAY EVENING PRECIP SHOULD BE ON THE DECLINE
BOTH IN THE MTNS AND ALONG THE PALMER DIVIDE WITH SUBSIDENCE ON
THE BACK SIDE OF THE PASSING UPPER TROUGH. HOWEVER WEST-NORTHWEST
MID-LEVEL FLOW SHOULD CONTINUE TO PRODUCE AREAS OF OROGRAPHIC
SNOWFALL ROUGHLY ALONG AND WEST OF THE CONTINENTAL DIVIDE THROUGH
SATURDAY EVENING. DO NOT SEE MUCH IF ANY NEW ACCUMULATION.
OTHERWISE THIS SAME FLOW WILL DRY THINGS IN THE LOWER ATMOSPHERE
EAST OF THE MTNS ON SATURDAY. HOWEVER PASSING MID-LEVEL MOISTURE
IS EXPECTED TO PRODUCE PARTLY TO MOSTLY CLOUDY SKIES FOR MUCH OF
THE DAY. CLOUDS NOT EXPECTED TO DELAY WARMUP WITH MAX TEMPS ON
THE PLAINS 8-14F WARMER THAN READINGS ON FRIDAY.
FOR SUNDAY AND BEYOND...UPPER RIDGE BUILDING OVER THE GREAT BASIN
MIGRATES SLOWLY EASTWARD OVER THE ROCKY MTN REGION WITH HIGHEST
HEIGHTS...WARMEST TEMPS ALOFT...OVER COLORADO MONDAY/MONDAY
NIGHT. COULD SEE MAX TEMPS AS MUCH AS 10DEG F ABOVE AVERAGE FOR
THE DATE. WINDS NOT MUCH OF A CONCERN SUNDAY-TUESDAY. THEN BY
MID-WEEK...MEDIUM RANGE MODELS SHOW THIS RIDGE MOVING EAST AND
THE NEXT POTENT UPPER AIR TROUGH MOVING OVER THE GREAT BASIN.
SHOULD THIS OCCUR COULD SEE SNOW CHANCES RETURNING TO THE HIGH
COUNTRY AND THE DEVELOPMENT OF STG/GUSTY SOUTH-SOUTHWESTERLY
WINDS BOTH MTNS AND PLAINS.
AVIATION...SNOW DEVELOPING AGAIN ACROSS DENVER AREA...SHOULD
PERSIST THROUGH MUCH OF THE EVENING. MVFR CONDITIONS SHOULD
PREVAIL THROUGH 03Z WITH A CHANCE FOR IFR IN HEAVIER SNOW BANDS.
SHOULD SEE CONDITIONS IMPROVE TO VFR AFTER 03Z...THOUGH CEILINGS
AROUND 5000 FEET AGL WILL PREVAIL. NEXT WAVE TO AFFECT AREA AROUND
10Z WITH MVFR CONDITIONS REDEVELOPING AS SNOW SPREADS BACK INTO
REGION. DRIER AIR TO MOVE INTO THE AREA AFTER 16Z AS WINDS BECOME
NORTHWEST. VFR TO PREVAIL THROUGH THE AFTERNOON.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 5 PM MST FRIDAY FOR COZ033-034. WINTER
WEATHER ADVISORY UNTIL 5 PM MST FRIDAY FOR COZ036-041. WINTER STORM
WARNING UNTIL 5 PM MST FRIDAY FOR COZ031.
&&
$$
SHORT TERM...BARJENBRUCH
LONG TERM....MEIER
AVIATION...BARJENBRUCH
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1035 PM MST THU MAR 1 2012
.UPDATE...
LINGERING SHOWERS WILL BE POSSIBLE AT KCOS AND KPUB THROUGH
08Z. PLAN TO CARRY VCSH IN KPUB TAF...AND A BRIEF TEMPO GROUP FOR
KCOS THROUGH THIS PERIOD. CIGS SHOULD MAINLY STAY IN THE MVFR
CATEGORY FOR BOTH TAF SITES THROUGH THE REMAINDER OF THE NIGHT.
NEW SUITE OF MODELS SUGGESTS NEXT ROUND WILL MOVE IN TOMORROW
MORNING AFTER 12Z FOR KCOS AND KALS...AND AFTER 13-14Z FOR KPUB.
CIGS COULD DROP LOCALLY INTO THE IFR CATEGORY WITH THE HEAVIER
CONVECTIVE SNOW SHOWERS...ESPECIALLY OVER THE MOUNTAIN AREAS WHERE
MTN OBSCURATIONS CAN BE EXPECTED IN +SHSN. ADDITIONAL SNOWFALL
ACCUMULATIONS AT TERMINALS WILL MOST LIKELY REMAIN AROUND AN INCH
OR LESS...HOWEVER IF A CONVECTIVE SNOW BAND SETS UP OVER THE
TERMINAL...A QUICK 2 INCHES OF ACCUMULATION WOULD BE POSSIBLE. EXPECT
GRADUALLY IMPROVING CONDITIONS DURING THE LATE AFTERNOON AND EARLY
EVENING...WITH SOME SPORADIC ISOLATED INSTABILITY SNOW SHOWERS
CONTINUING THROUGH THE EVENING BEFORE CLEARING OUT OVERNIGHT. -KT
&&
.PREV DISCUSSION... /ISSUED 522 PM MST THU MAR 1 2012/
UPDATE...
COLD FRONT STARTING TO PUSH INTO THE EXTREME SOUTHERN PORTIONS OF
THE SOUTHEAST PLAINS...INTO LAS ANIMAS AND BACA COUNTIES. FALLING
TEMPERATURES AND INCREASING HUMIDITIES SHOULD BRING A QUICK END
TO THE RED FLAG WARNING FOR THOSE AREAS...WITH KTAD ALREADY ABOVE
THE CRITICAL RH THRESHOLD...AND KSPD NEARING THAT. THUS HAVE UPDATED
TO ALLOW THE RED FLAG WARNING TO EXPIRE. HAVE ALSO UPDATED GRIDS
TO REFLECT CURRENT TEMPERATURES/HUMIDITIES/WINDS BEHIND THE FRONT
WHICH MOVED THROUGH FASTER THAN NAM12 HAD SUGGESTED. HRRR APPEARS
TO HAVE A GOOD HANDLE ON IT...AND LEANED HEAVILY ON IT FOR GRID
PRODUCTION. OTHERWISE...POPS SEEM IN GOOD SHAPE. WITH CONVECTIVE
NATURE OF SNOW...WOULDN`T BE SURPRISED TO SEE A QUICK INCH OR TWO OF
SNOW ACROSS SOUTHERN EL PASO AND NORTHERN PUEBLO COUNTIES OVER THE
NEXT COUPLE HOURS BEFORE SHORTWAVE PUSHES EASTWARD. -KT
PREV DISCUSSION... /ISSUED 341 PM MST THU MAR 1 2012/
SHORT TERM...
(TONIGHT AND FRIDAY)
BROAD UPPER TROUGH REMAINS ACROSS THE INTERMOUNTAIN WEST WITH AN
EMBEDDED SHORT WAVE LIFTING OUT ACROSS THE CENTRAL ROCKIES AS
SECONDARY ENERGY IS DIGGING INTO THE NORTH GREAT BASIN AT THIS TIME.
AT THE SFC...BOUNDARY ASSOCIATED WITH CENTRAL ROCKIES SHORT WAVE
CURRENTLY VISIBLE ON KPUX RADAR BANKED UP ACROSS THE LOWER EASTERN
SLOPES OF RAMPART RANGE BACK THROUGH NORTHEASTERN PUEBLO COUNTY AND
INTO CENTRAL OTERO...BENT AND PROWERS COUNTIES AT THIS TIME. GUSTY
WESTERLY WINDS CONTINUE SOUTH OF THE BOUNDARY...KEEPING RED FLAG
CONDITIONS IN PLACE ACROSS THE SOUTHERN TIER ZONES AT THIS TIME.
TONIGHT AND FRIDAY...FIRST EMBEDDED WAVE CONTINUES TO LIFT OUT INTO
THE CENTRAL HIGH PLAINS THIS EVENING ALLOWING FOR FRONTAL BOUNDARY
TO CONTINUE TO SLIDE SOUTH AND WEST ACROSS ALL OF THE EASTERN PLAINS
THROUGH THE LATE EVENING. PASSING WAVE WILL KEEP SNOW...HEAVY AT
TIMES...ACROSS THE MTS OF THE CONTINENTAL DVD THROUGH THE
EVENING...WITH A SHORT LULL IN SNOWFALL EXPECTED LATER TONIGHT.
PASSING WAVE AND FRONT WILL ALSO PROVIDE LIFT FOR LIGHT SNOWFALL
ACROSS THE REST OF THE HIGHER TERRAIN AND ACROSS THE EASTERN PLAINS
THIS EVENING WITH BEST POPS ACROSS THE HIGHER ELEVATIONS OF THE
EASTERN MTS AND ACROSS THE PALMER DVD WITH NORTHERLY UPSLOPE WINDS
BEHIND FRONT. SHOULD ALSO SEE PRECIPITATION DIMINISHING ACROSS THE
EASTERN MTS AND PLAINS LATER TONIGHT...THROUGH COULD CONTINUE TO
SEE LIGHT SNOW ACROSS EASTERN SLOPES AND IMMEDIATE ADJACENT PLAINS
WITH GENERALLY WEAK MOIST LOW LEVEL UPSLOPE FLOW.
SECONDARY WAVE CONTINUES TO DIG ACROSS THE GREAT BASIN LATE TONIGHT
WHICH IS THEN PROGGED TO CONTINUE ACROSS THE STATE THROUGH THE DAY
TOMORROW...PROVIDING ANOTHER ROUND OF SNOWFALL TO THE MTS AND
IMMEDIATE ADJACENT PLAINS...AS A SECONDARY NORTHERLY SURGE OF COLD
AIR MOVES ACROSS EASTERN COLORADO. WITH THAT SAID...HAVE UPGRADED
AND ISSUED WINTER STORM WARNINGS FOR THE HIGHER ELEVATIONS OF THE
EASTERN MTS...AND THE PALMER DVD AND HAVE KEPT CURRENT HIGHLIGHTS IN
PLACE ACROSS THE CENTRAL AND SOUTHWEST MTS. LATEST LOCAL WRF DATA
INDICATING A MORE EASTERLY SFC-H7 FLOW ACROSS THE I-25 CORRIDOR
THROUGH THE DAY TOMORROW...WHICH WOULD BRING MORE SNOWFALL THAN
CURRENTLY FORECAST TO SOUTHERN PORTIONS OF EL PASO COUNTY...NORTHERN
PUEBLO COUNTY AND FREMONT COUNTY...AS WELL AS THE SOUTHERN I-25
CORRIDOR...THOUGH WILL LET THE NEXT SHIFTS GET A LOOK AT NEWER DATA
TO DECIDE ON ANY ADDITIONAL HIGHLIGHTS. -MW
LONG TERM...
FRI NITE - THU)
.STORM MOVING OUT AT THE BEGINNING OF THIS PERIOD...AND A NEW
STORM MOVING IN AT THE END OF THIS PERIOD...QUIET IN-BETWEEN...
THE HEADLINE ABOVE PRETTY MUCH TELLS THE STORY OF THE WEATHER
BETWEEN FRIDAY NIGHT INTO NEXT THURSDAY. STORM WHICH HAS BEEN
BRINGING SNOW TO THE CONTDVD AND PROMISES TO BRING SOME NEEDED
PRECIP TO THE E MTNS...I-25 CORRIDOR REGION...WILL BE MOVING OUT OF
THE AREA FRIDAY EVENING. SNOW WILL LIKELY BE STILL GOING ACROSS THE
RATON MESA REGION EARLY FRIDAY EVENING BUT SHOULD CLEAR OUT OF THE
AREA BY MIDNIGHT.
FROM SAT THRU TUESDAY...IT WILL BE MAINLY DRY OVER THE REGION
THROUGH THE PERIOD. THE ONLY EXCEPTION WILL BE ACROSS THE C MTNS
WERE SOME SNOW SHOWERS WILL BE POSSIBLE AT THE HIGHEST ELEVATIONS.
ACROSS THE REMAINDER OF THE AREA...TEMPERATURES WILL BE WARMING UP
QUITE A BIT....WITH TEMPS ON THE PLAINS AROUND 50F SAT...AROUND 60
SUNDAY...U60S MONDAY...AND AROUND 70 TUESDAY. BY WEDNESDAY...THE
NEXT BIG PACIFIC TROUGH WILL BE MOVING INTO THE REGION AND THIS
SYSTEM ONCE AGAIN PROMISES TO BRING SNOW TO THE C MTNS AND POSSIBLY
LOWER ELEVATIONS BY MID TO LATE WEEK. THERE IS STILL SOME
UNCERTAINTY THIS FAR OUT AND ONLY SLIGHT POPS ARE MENTIONED AT THE
HIGHER ELEVATIONS DURING THE MID WEEK TIME PD...BUT IF THE MODELS
CONTINUE TO SHOW CONSISTENCY...THEN POP VALUES WILL HAVE TO BE
RAMPED UP.
WITH ANOTHER STRONG TROUGH POSSIBLE AND LAPSE RATES INCREASING WITH
THE INCREASING SUN ANGLE...WE WILL LIKELY BE DEALING WITH MORE FIRE
WX ISSUES TUES AND WEDNESDAY. /34
AVIATION...
RADAR DATA AND OBS INDICATING SFC BOUNDARY PUSHED THROUGH KPUB AND
TRAILS BACK SOUTH AND EAST FROM SOUTH OF KLHX TO NORTH OF KSPD.
FRONT WILL CONTINUE TO SLIDE SOUTH AND WEST ACROSS THE REST OF THE
PAINS THIS EVENING...WITH LOW LEVEL UPSLOPE FLOW PERSISTING
OVERNIGHT. GUSTY NORTH TO NORTHEAST WINDS 15-30KTS AT KCOS AND KPUB
WILL BE COME MORE EASTERLY AND DIMINISH AFT 06Z. MVFR CONDITIONS
WITH SCATTERED SHOWERS AT BOTH TERMINALS THROUGH 06Z WITH UPSLOPE
KEEP MVFR AND LOCAL IFR CIGS ACROSS KCOS AND KPUB THROUGH THE EARLY
MORNING WHEN A SECONDARY COLD FRONT WILL BRING GUSTY NORTHERLY WINDS
AND CHANCES OF SNOW TO BOTH TERMINALS THROUGH 18Z. KALS...WILL
CONTINUE TO SEE GUSTY WEST TO SOUTHWEST WINDS THROUGH 06Z ALONG WITH
BRIEF MVFR CONDITIONS IN PASSING SHOWERS. -MW
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 11 AM MST FRIDAY FOR COZ059-061-
063.
WINTER WEATHER ADVISORY UNTIL 11 PM MST FRIDAY FOR COZ072-074-
079.
WINTER STORM WARNING UNTIL 11 AM MST FRIDAY FOR COZ058-060.
WINTER STORM WARNING UNTIL 11 PM MST FRIDAY FOR COZ073-075-080.
WINTER WEATHER ADVISORY UNTIL 2 PM MST FRIDAY FOR COZ064-067.
WINTER STORM WARNING UNTIL 2 PM MST FRIDAY FOR COZ066-068.
WINTER WEATHER ADVISORY UNTIL 5 PM MST FRIDAY FOR COZ081-084.
WINTER STORM WARNING UNTIL 5 PM MST FRIDAY FOR COZ082.
&&
$$
31/88
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
105 AM EST FRI MAR 2 2012
.SYNOPSIS...
A WEAKENING COLD FRONT STALLING NORTH AND WEST OF THE AREA
OVERNIGHT. A STRONG COLD FRONT WILL THEN MOVE THROUGH THE AREA
LATE SATURDAY AFTERNOON AND SATURDAY EVENING. HIGH PRESSURE WILL
BUILD BACK INTO THE REGION ON SUNDAY AND WILL REMAIN THE DOMINANT
WEATHER FEATURE THROUGH MUCH OF NEXT WEEK. A WEAK COASTAL TROUGH
MAY FORM OVER THE NEARBY ATLANTIC DURING THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
OVERNIGHT...ANOTHER UNSEASONABLY WARM AND HUMID SETUP FOR OUR REGION
AS A NEARLY STATIONARY FRONTAL BOUNDARY EXTENDS FROM FAR NW SOUTH
CAROLINA INTO NE NORTH CAROLINA. WITH S TO SW SURFACE FLOW THROUGH
THE LOWER LEVELS AND SURFACE DEW POINTS IN THE LOWER 60S...WE
THINK TEMPS WILL BE SLOW TO FALL OVERNIGHT...ESPECIALLY AS THE
STEADY STREAM OF MID/HIGH CLOUDS CONTINUE OVER GEORGIA AND SOUTH
CAROLINA.
REGIONAL SOUNDINGS AND RUC MESOANALYSIS SHOW THE MID LEVELS HAVE
BECOME MORE STABLE. MODELS INDICATE PWATS SURGING N OVERNIGHT
WITH GULF MOISTURE WORKING INTO THE REGION ALONG WITH IMPROVING
MID LEVEL LAPSE RATES LATE. WE HAVE TRIMMED POPS BACK TO 20
PERCENT LATE OVER THE NW TIER...IN TANDEM WITH THE BELT OF DEEPER
MOISTURE LIFTING N THROUGH THE CAROLINAS.
THE NOCTURNAL INVERSION IS EXPECTED TO TRAP ABUNDANT LOW LEVEL
MOISTURE LATE TONIGHT...ESPECIALLY IN AREAS WHERE DECENT RAINFALL
OCCURRED. WHILE WE CONTINUE TO INCLUDE PATCHY FOG...WE HAVE BACKED
OFF ITS DEVELOPMENT UNTIL AFTER 3 OR 4 AM.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH SUNDAY/...
MODEL SOLUTIONS ARE IN RELATIVELY GOOD AGREEMENT THROUGH THE SHORT
TERM PERIODS THIS AFTERNOON...WITH JUST SOME MINOR DIFFERENCES NOTED
WITH RESPECT TO THE COLD FRONTAL PASSAGE LATE SATURDAY AFTERNOON AND
SATURDAY EVENING.
FRIDAY AND FRIDAY NIGHT...A WARM FRONT WILL LIFT NORTHWARD
THROUGH NORTHERN PORTIONS OF THE FORECAST AREA FRIDAY
MORNING...WITH RIDGING THEN BUILDING BACK INTO THE REGION FRIDAY
AFTERNOON AND FRIDAY NIGHT. MOISTURE TRANSPORT ON THE NOSE OF
25-30 KNOT H85 JET ALONG WITH MID-LEVEL LAPSE RATES AROUND 7 C/KM
WILL NECESSITATE SLIGHT CHANCE/LOW CHANCE POPS FOR
SHOWERS/THUNDERSTORMS ACROSS NORTHERN ZONES FRIDAY MORNING. THE
ACTIVITY ASSOCIATED WITH THE WARM FRONT SHOULD BE NORTH OF THE
SOUTH SANTEE RIVER BY NOON FRIDAY...AND WITH NO LARGE SCALE
FORCING MECHANISM IN PLACE TO PROVIDE ASCENT FRIDAY AFTERNOON AND
FRIDAY NIGHT...WILL KEEP THE FORECAST RAIN FREE. LOW LEVEL
THICKNESS VALUES SUPPORT HIGHS IN THE MID 80S...BUT WITH MORNING
CLOUD COVER AND SKIES NOT CLEARING OUT ENTIRELY DURING THE
AFTERNOON...WE DON/T EXPECT TO REACH VALUES QUITE THIS HIGH. WILL
KEEP FORECAST MAX TEMPERATURES AROUND 80 TO THE LOWER 80S AWAY
FROM THE COAST. OVERNIGHT LOWS ARE EXPECTED TO BOTTOM OUT IN THE
LOWER 60S.
SATURDAY THROUGH SUNDAY...DEEP SOUTHWESTERLY FLOW WILL BE IN
PLACE TO START THINGS OFF SATURDAY IN ADVANCE OF AN APPROACHING
COLD FRONT. THIS COLD FRONT WILL MOVE THROUGH THE FORECAST AREA
LATE SATURDAY AFTERNOON AND SATURDAY EVENING...BUT WON/T PROGRESS
TOO FAR OFF THE COAST INITIALLY. THE COLD FRONT WILL STALL NEAR
THE GULF STREAM SATURDAY NIGHT...AWAITING THE PUSH OF A STRONG
UPPER LEVEL TROUGH EARLY SUNDAY TO KICK IT FURTHER OUT TO SEA.
HIGH PRESSURE WILL THEN BUILD BACK INTO THE AREA SUNDAY AFTERNOON.
AS FOR FORECAST DETAILS...WILL KEEP SHOWERS/ISOLATED THUNDERSTORMS
CONFINED TO WESTERN ZONES SATURDAY MORNING...WITH RAIN FREE
CONDITIONS ANTICIPATED FOR COASTAL ZONES. DEEPER MOISTURE AND BETTER
FORCING FOR ASCENT WILL OVERSPREAD THE FORECAST AREA WITH THE
APPROACH OF THE COLD FRONT SATURDAY AFTERNOON...SO WILL CARRY LIKELY
POPS FOR SHOWERS/THUNDERSTORMS ACROSS THE VAST MAJORITY OF THE AREA.
STILL QUITE A BIT OF UNCERTAINTY WITH RESPECT TO THE POTENTIAL FOR
SEVERE WEATHER...AS IT WILL BE HIGHLY DEPENDENT ON THE AMOUNT OF
SURFACE BASED INSTABILITY WHICH MANAGES TO OCCUR. MODEL SOLUTIONS
SHOW QUITE A BIT OF MID/HIGH CLOUD COVER WILL BE IN PLACE THROUGH
THE DAY SATURDAY...AND THIS WOULD GREATLY LIMIT THE AMOUNT OF
DESTABILIZATION THAT COULD OCCUR. THE NAM12 SHOWS SURFACE BASED CAPE
VALUES INCREASING TO AROUND 500 J/KG WITH LIFTED INDICES LOWERING TO
BETWEEN -2 AND -3. ALTHOUGH THE INSTABILITY APPEARS THAT IT WILL BE
FAIRLY LIMITED...THE STRONGLY SHEARED ENVIRONMENT AND STRONG WIND
FIELDS ALOFT DO SUGGEST THERE WILL BE SOME POTENTIAL FOR SEVERE
WEATHER. THAT SAID...THE BEST DYNAMIC FORCING FOR ASCENT APPEARS
THAT IT WILL REMAIN DISPLACED WELL TO THE WEST OF THE COLD
FRONT...LIMITING THE POTENTIAL FOR A WELL ORGANIZED SEVERE WEATHER
EVENT...SO WILL HOLD OFF ON MENTIONING SEVERE WEATHER IN THE
HAZARDOUS WEATHER OUTLOOK AT THIS TIME.
THE COLD FRONT WILL STALL JUST OFFSHORE SATURDAY EVENING...KEEPING
DEEP MOISTURE IN PLACE ACROSS THE FORECAST AREA WHILE STRONGER UPPER
LEVEL FORCING FOR ASCENT OVERSPREADS THE REGION IN ADVANCE OF THE
APPROACHING UPPER LEVEL TROUGH. AS A RESULT...WILL CONTINUE TO KEEP
POPS IN THE LIKELY RANGE ALL LOCALES SATURDAY NIGHT. SHOWERS AND
THUNDERSTORMS SHOULD BE ONGOING SATURDAY EVENING ACROSS MUCH OF THE
FORECAST AREA...WITH THE PROBABILITY FOR THUNDER THEN STEADILY
DIMINISHING THROUGH THE NIGHT AS PRECIPITATION TRANSFORMS FROM MORE
OF A SHOWERY NATURE TO A GENERAL LIGHT TO MODERATE RAIN. THE RAIN IS
EXPECTED TO QUICKLY CLEAR THE AREA FROM WEST TO EAST SUNDAY MORNING
AS THE STRONG UPPER LEVEL TROUGH SHIFTS THROUGH THE REGION AND KICKS
THE STALLED OUT COLD FRONT AND ASSOCIATED BAND OF DEEPER MOISTURE
FURTHER OFFSHORE AND INTO THE ATLANTIC.
TEMPERATURES ARE EXPECTED TO TOP OUT IN THE MID TO UPPER 70S ON
SATURDAY...WITH LOWS SATURDAY NIGHT IN THE MID TO UPPER 40S. MUCH
COOLER CONDITIONS ARE EXPECTED ON SUNDAY...WITH HIGHS IN THE LOWER
60S MOST LOCALES.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
A SECONDARY COLD FRONT WILL MOVE THROUGH ON MONDAY...BUT WITH THE
DRY WEST AND NW FLOW ALOFT IT/LL COME THROUGH DRY AND GENERALLY FREE
OF EVEN ANY CLOUD COVER. HIGH PRESSURE THEN BUILDS FROM THE OH/TN
VALLEYS IN WAKE OF THIS FRONT...AND SHIFTS TOWARD THE MID ATLANTIC
COAST TUESDAY. THE HIGH WILL THEN PROGRESS INTO THE ATLANTIC FOR
WEDNESDAY AND THURSDAY...AND AS IT DOES SO WE EXPECT A COASTAL TROUGH
TO DEVELOP OVER THE NEARBY ATLANTIC WATERS. THE RETURN OF MOISTURE
WILL BE SLOW...BUT GRADUAL WITH THE SYNOPTIC FLOW BECOMING NE AND
EAST DURING THE MIDDLE OF THE WEEK. EVENTUALLY THIS MAY ALLOW FOR A
FEW SHOWERS TO CREEP ONSHORE...BUT NOTHING MORE THAN ISOLATED
ACTIVITY IS EXPECTED AT THIS TIME. TEMPS LOOK TO BE NEAR OR EVEN
BELOW NORMAL THROUGH WEDNESDAY...WITH SOME MODERATION THURSDAY.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
EVENTUALLY MVFR CONDITIONS WILL DEVELOP AT BOTH TERMINALS BEFORE
DAYBREAK...THE RESULT OF YESTERDAY RAINFALL AND/OR POOLING OF
MOISTURE BENEATH THE NOCTURNAL INVERSION. IN ADDITION WE COULD SEE
A FEW HOURS OF IFR WEATHER FROM 11-15Z...BUT PROBABILITIES ARE NOT
ENOUGH TO INCLUDE WITH THE LATEST TAFS. VFR WEATHER THEN RETURNS
FOR THE BULK OF THE DAY FRIDAY INTO THE FIRST PART OF FRIDAY NIGHT.
SOUNDINGS AND THE VAD WIND PROFILE ARE SHOWING WINDS NEAR 30 KT AT
2K FEET...WHICH CONTINUES THE FIRST FEW HOURS OF THE 06Z TAF
CYCLE. SOUTH AND SW SURFACE WINDS WILL BECOME GUSTY FRIDAY
AFTERNOON...AS MIXING HEIGHTS TAP INTO 20-25 KT WINDS WITHIN THE
BOUNDARY LAYER. WIND SHEAR IS LIKELY AGAIN FRIDAY NIGHT AND WILL
BE INCLUDED IN LATER TAF ISSUANCES.
EXTENDED AVIATION OUTLOOK...MVFR OR LOWER CIGS/VSBYS APPEAR TO BE A
FAIRLY GOOD PROBABILITY SATURDAY THROUGH EARLY SUNDAY AS A SLOW
MOVING COLD FRONT MOVES THROUGH WITH WIDESPREAD SHOWERS AND
THUNDERSTORMS. VFR CONDITIONS WILL RETURN SUNDAY AFTERNOON THROUGH
TUESDAY AS HIGH PRESSURE BUILDS BACK INTO THE AREA. WIND SHEAR
AND/OR GUSTY SURFACE WINDS WILL IMPACT THE TERMINALS FRIDAY NIGHT
THROUGH SATURDAY.
&&
.MARINE...
SW FLOW OVERNIGHT...IN THE 10-15 KT RANGE THIS EVENING...DIMINISHING
SEAWARD AS THE LOW LEVEL JET SLOWLY WEAKENS. SEAS 2 TO 4 FT FOR
THE MOST PART...LOWEST AROUND GRAYS REEF AND HIGHEST FROM BUOY SIX
OFF THE CHARLESTON COUNTY OUT TO BUOY 41004 AND PERHAPS WELL OFF
THE GEORGIA COAST BEYOND 40 NM OFFSHORE.
FRIDAY THROUGH TUESDAY...A WEAK WARM FRONT WILL LIFT NORTHWARD
THROUGH THE SOUTH CAROLINA WATERS FRIDAY MORNING. A STRONG COLD
FRONT WILL APPROACH FROM THE WEST ON SATURDAY AND MOVE THROUGH THE
MARINE AREA SATURDAY NIGHT. HIGH PRESSURE WILL THEN BUILD BACK
INTO THE REGION ON SUNDAY AND WILL REMAIN THE DOMINANT WEATHER
FEATURE THROUGH EARLY NEXT WEEK.
INCREASING SOUTH-SOUTHWEST FLOW IN ADVANCE OF THE COLD FRONT COULD
LEAD TO SMALL CRAFT HEADLINES ACROSS PORTIONS OF THE WATERS FRIDAY
NIGHT THROUGH SUNDAY FOR WINDS/SEAS OR A COMBINATION OF THE TWO.
CONDITIONS ARE EXPECTED TO REMAIN BELOW HEADLINE THRESHOLDS SUNDAY
NIGHT THROUGH MONDAY. SMALL CRAFT CONDITIONS MAY AFFECT PORTIONS OF
THE WATERS AGAIN MONDAY NIGHT AND TUESDAY AS THE GRADIENT PINCHES
DUE TO COASTAL TROUGH DEVELOPMENT OFF THE SOUTHEAST COAST.
&&
.CLIMATE...
RECORD MAX TEMPS FOR MARCH 2...
KCHS...85 SET IN 1997 AND PREVIOUS YEARS.
KCHL...81 SET IN 1976.
KSAV...86 SET IN 1951.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
345 AM CST FRI MAR 2 2012
...UPDATED SYNOPSIS...SHORT TERM...AND LONG TERM DISCUSSIONS...
.SYNOPSIS...
ISSUED AT 345 AM CST FRI MAR 2 2012
02.00Z 300 HPA MAP ANALYSIS SHOWED A STRONG 140 KT MERIDIONAL JET FROM
BRITISH COLUMBIA INTO NW NEVADA. THIS JET WAS WRAPPING AROUND A SERIES
OF VORTMAXES AND ASSOCIATED SHORT WAVE TROUGHS IN THE MID LEVELS LOCATED
ACROSS THE ROCKIES. ANOTHER STRONG 125 KT JET WAS MOVING ACROSS OKLAHOMA.
VERY COLD AIR AT 500 HPA WAS NOTED ACROSS THE NORTHERN GREAT BASIN INTO
THE NORTHERN ROCKIES WITH -30S DEG C VALUES. AT 700 AND 850 HPA, COLD
AIR ADVECTION WAS NOTED ACROSS THE NORTHERN AND CENTRAL PLAINS BETWEEN
12Z AND 00Z RAOBS. AT THE SFC, A COLD FRONT WAS LOCATED ACROSS OKLAHOMA
WITH DEWPOINTS IN THE 60S DEG F SOUTH OF THIS BOUNDARY.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 345 AM CST FRI MAR 2 2012
TODAY:
KDDC WSR-88D IS INDICATING RETURNED POWER FROM LIGHT SNOW SHOWERS EARLY
THIS MORNING. THIS IS AN IMMEDIATE NEAR TERM CONCERN. ONCE THESE SHOWERS
DISSIPATE, A QUIET WEATHER DAY IS EXPECTED ACROSS SOUTHWEST KANSAS.
THIS ACTIVITY IS ASSOCIATED WITH A 400 HPA PV ANOMALY ROTATING ACROSS
THE STATE AT THE BASE OF AN UPPER LEVEL SHORTWAVE TROUGH EJECTING ACROSS
THE NORTHERN PLAINS. TWO AREAS OF ENHANCED PETERSON FRONTOGENESIS IN
THE 850-650 HPA LAYER WILL WEAKEN/MOVE OUT OF THE AREA BY MID MORNING.
AS A RESULT, HAVE TAPER POPS TO THE SOUTHWEST THROUGH MORNING. HIGH
PRESSURE WILL BUILD ACROSS KANSAS. WE WILL SEE A SLIGHT DOWNSLOPE NNW
WIND WITH MIXING UP TO 700 HPA. EXPECTING MAXIMUM TEMPERATURES IN THE
UPPER 40S DEG F ACROSS WEST CENTRAL KANSAS AND LOW 50S DEG F ACROSS
SOUTH CENTRAL KANSAS. IN ADDITION, THE MID LEVELS AT 500 HPA WILL COOL
AS A COLD POOL (~-33 DEG C MOVES OVERHEAD) SO WE COULD SEE SOME CUMULUS
BUILDUPS TODAY.
TONIGHT:
TRANQUIL WEATHER IS EXPECTED THIS EVENING AS HIGH PRESSURE PREVAILS
ACROSS THE PLAINS. SKIES WILL CLEAR THROUGH EVENING AND A LIGHT NORTHWESTERLY
WIND IS EXPECTED THROUGH THE OVERNIGHT. NOT EXPECTING ANY PRECIPITATION
THIS EVENING IN ASSOCIATION WITH SUBSIDENCE BEHIND AN UPPER LEVEL TROUGH
AND HIGH PRESSURE AT THE SFC. OVERNIGHT LOWS ARE EXPECTED TO BE IN THE
20S DEG F.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 345 AM CST FRI MAR 2 2012
SATURDAY THROUGH SUNDAY NIGHT:
ONLY SUBTLE CHANGES WERE REQUIRED TO THE GRIDS AS THIS WILL BE A RELATIVELY
QUIET SENSIBLE WEATHER PERIOD. THE MAIN CHALLENGE WILL BE DEWPOINT/RH
FORECAST SATURDAY AS NORTHWESTERLY DOWNSLOPE CONDITIONS WILL ALLOW THE
LOWER TROPOSPHERE TO BECOME VERY DRY (DEWPOINT TEMPERATURES LIKELY IN
THE SINGLE DIGITS FAHRENHEIT). AS TEMPERATURES SATURDAY TOP OUT IN THE
48 TO 51 DEGREE RANGE IN THE WEST...AFTERNOON RH WILL FALL TO AT LEAST
THE UPPER TEENS IF NOT LOWER. WILL HAVE TO BE MINDFUL OF CRITICAL FIRE
WEATHER CONDITIONS DEVELOPING AS AFTERNOON MIXING WILL ALLOW NORTHWEST
WINDS TO PROBABLY REACH THE WIND CRITERIA (SUSTAINED/FREQUENT GUSTS
25 MPH). ON SUNDAY...NORTHWESTERLY DOWNSLOPE FLOW WILL CONTINUE...BUT
THE LOWER TROPOSPHERE WILL CONTINUE TO WARM WITH HIGHS WELL INTO THE
LOWER TO MID 60S FOR MOST AREAS OF THE DDC FORECAST AREA. THE MODELS
SHOW A MODEST IMPROVEMENT IN DEWPOINT TEMPERATURES, BUT THE WARMER
TEMPERATURES WILL COUNTER THIS AND ANOTHER DAY OF N EAR CRITICAL
FIRE WEATHER CONDITIONS WILL BE POSSIBLE.
MONDAY THROUGH THURSDAY:
THE BIG FORECAST CHALLENGE WILL BE MID-WEEK AS THE GLOBAL MODELS SUGGEST
AN ANTICYCLONIC WAVE-BREAKING LOW DEVELOPING OVER THE INTERMOUNTAIN
WEST MOVING INTO THE SOUTHERN ROCKIES BY WEDNESDAY NIGHT/THURSDAY.
AHEAD OF THIS PATTERN CHANGE...VERY WARM AND QUIET SENSIBLE WEATHER
IS EXPECTED MONDAY AND TUESDAY. A TROUGH WITHIN THE ACTIVE NORTHERN
STREAM JET IS EXPECTED TO TRAVEL EAST ACROSS THE NORTH CENTRAL CONUS
WHICH WILL BRING A FAIRLY STRONG COLD FRONT SOUTH WEDNESDAY. WEDNESDAY
FORECAST IS VERY CHALLENGING ESPECIALLY REGARDING DAYTIME TEMPERATURES.
THE STRONG COLD FRONT WILL LIKELY MOVE SOUTH THROUGH SOUTHWEST KANSAS
DURING THE DAY RESULTING IN FALLING AFTERNOON TEMPERATURES IN THE NORTH.
MOISTURE RETURN AHEAD OF THE FRONT WEDNESDAY IS SHOWN IN THE GFS AND
ECMWF MODELS WITH THE PROBABILITY OF PRECIPITATION INCREASING BY LATE
IN THE DAY WEDNESDAY ALONG THIS FRONT. PRECIPITATION CHANCES THEN INCREASE
WEDNESDAY NIGHT AS THE UPPER LOW OVER ARIZONA BEGINS TO MOVE EAST INTO
NEW MEXICO. AT THIS TIME...THE WX GRIDS WILL REFLECT SHOWERS AND ISOLATED
THUNDER IN THE SOUTH CENTRAL KANSAS COUNTIES WITH RAIN IN THE CENTRAL
KANSAS COUNTIES NORTH OF THE FRONT. THIS IS THINKING RIGHT NOW...HOWEVER
THIS FORECAST IS SUBJECT TO CHANGE (AND IT MOST LIKELY WILL) AS WE GET
CLOSER TO THIS POTENTIAL PRECIPITATION EVENT TOWARD MID-NEXT WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1102 PM CST THU MAR 1 2012
LATEST HRRR/NAM SHOW THAT THIS PRECIP EVENT PROBABLY WILL HAVE SIG IMPACTS
TO AVIATION. FRCST COMP REFLECTIVITY FROM THE HRRR IS NOT THAT IMPRESSIVE
NOR IS QPF AMOUNTS. HAVE -SN FOR KGCK/KHYS AS THESE TERMINALS WILL BE
CLOSER TO THE 700 HPA BAROCLINIC ZONE/TROUGH AND WITHIN A ZONE OF HIGHER
OMEGA/ISEN LIFT. KHYS MIGHT SEE A REDUCTION TO MVFR CIGS THROUGH MORNING,
HOWEVER, CIGS WILL GENERALLY REMAIN VFR WHICH IS FORECAST BY THE HRRR.
VERY COLD AIR 500 HPA AROUND -33DEGC WILL SPREAD OVER W KS IN ASSOCIATION
WITH AN UL TROUGH SO CUMULUS BUILDUPS ARE POSSIBLE LATER TODAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 51 23 51 30 / 10 0 10 0
GCK 49 22 50 29 / 20 0 10 0
EHA 45 22 50 29 / 30 0 10 0
LBL 50 21 51 29 / 20 0 10 0
HYS 50 24 50 30 / 10 0 10 0
P28 54 28 53 32 / 10 0 10 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...SUGDEN
SHORT TERM...SUGDEN
LONG TERM....UMSCHEID
AVIATION...SUGDEN
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1052 PM MST THU MAR 1 2012
.UPDATE...
ISSUED AT 644 PM MST THU MAR 1 2012
BAND OF LIGHT SNOW HAS DEVELOPED ACROSS SOUTHERN PORTIONS OF KIT
CARSON COUNTY COLORADO STRETCHING EASTWARD THEN NORTHEASTWARD INTO
NORTHWEST KANSAS. KITR HAD A BRIEF PERIOD OF 3/4 MILE VISIBILITY
IN LIGHT SNOW WITH THAT PORTION OF THE BAND NOW SHIFTING EASTWARD
INTO SOUTHWEST PORTIONS OF SHERMAN COUNTY. ANOTHER AREA OF
ENHANCED REFLECTIVITY RESIDES OVER SOUTHWEST KIT CARSON COUNTY AND
CONTINUES TO SHIFT EASTWARD WITH TIME. PRIMARY CHANGES WERE TO
SPEED UP ONSET OF PRECIP ACROSS NORTHWEST KANSAS. ALSO MADE
SIGNIFICANT ADJUSTMENTS TO THE DEW POINT GRIDS AS TOP DOWN
MOISTENING HAS RESULTED IN DEW POINTS JUMPING INTO THE LOWER TO
MIDDLE 20S WHERE PRECIP IS FALLING.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 200 PM MST THU MAR 1 2012
A COLD FRONT THAT PASSED OVER THE CWA EARLY THIS MORNING IS NOW
ACROSS SOUTHWEST KANSAS AND SOUTHEAST COLORADO. EARLY AFTERNOON WV
IMAGERY AND RUC H5 ANALYSIS SHOW A BROAD TROUGH ACROSS THE WESTERN
US. A STRENGTHENING SHORTWAVE TROUGHS IS CURRENTLY MOVING INTO
WESTERN COLORADO.
TONIGHT THROUGH FRIDAY...SHORTWAVE TROUGH WILL MOVE OUT OF COLORADO
INTO WESTERN KANSAS. MOISTURE/LIFT WILL INCREASE FROM THE WET TO THE
EAST THIS EVENING AHEAD OF THIS FEATURE...WITH BEST LIFT/MOISTURE IN
THE 03-09Z TIMEFRAME. RAIN WILL QUICKLY TRANSITION TO SNOW IN THE
WEST THIS EVENING...WITH A RAIN/SNOW MIX IN THE EAST MOST OF THE
NIGHT. BY SUNRISE MOST LOCATIONS SHOULD SEE RAIN COMPLETELY
TRANSITION TO SNOW. GUIDANCE HAS TRENDED FURTHER SOUTH AND WEST ON
PLACEMENT OF HIGHEST SNOWFALL AMOUNTS...WHICH MAKES SENSE
CONSIDERING THE LOCATION OF SURFACE BAROCLINIC ZONE. WITH THIS IS
MIND...I INCREASED POPS ACROSS THE SOUTHWEST...AND DECREASED POPS IN
THE NORTHEAST. CONSIDERING THE LIMITED MOISTURE ADVECTION...AND
QUICK NATURE OF THIS SYSTEM...SNOWFALL AMOUNTS SHOULD REMAIN LIGHT.
RIGHT NOW HIGHEST AMOUNTS SHOULD BE LIMITED TO EASTERN COLORADO
WHERE 1-2 INCHES IS EXPECTED.
WITH LARGE SCALE SUBSIDENCE BUILDING BACK OVER THE CWA FRIDAY
MORNING FROM THE NORTH...PRECIPITATION SHOULD TAPER OFF QUICKLY FROM
THE NORTH TO THE SOUTH BY MID FRIDAY MORNING OVER ALL BUT THE
EXTREME SOUTHWEST PARTS OF THE CWA. DRY CONDITIONS ARE THEN EXPECTED
THROUGH FRIDAY AFTERNOON ACROSS ALL OF THE CWA.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 200 PM MST THU MAR 1 2012
MAIN WEATHER STORY FOR THE LONG TERM IS A WARMING TREND AS LARGE
UPPER RIDGE ALBEIT SOMEWHAT FLAT DEVELOPS OVER THE AREA. HIGH
TEMPERATURE SATURDAY IN THE 40S WILL WARM INTO THE 50S AND LOW 60S
SUNDAY. EVEN WARMER ON MONDAY WITH MID TO UPPER 60S AND MID 60S TO
LOW 70S TUESDAY.
TIMING DIFFERENCES SHOW UP WEDNESDAY AND THURSDAY AS THE WEST
COAST UPPER TROUGH MOVES TOWARD OR ACROSS THE AREA...IMPACTING THE
TEMPERATURE FORECAST. LOOKS TO REMAIN ABOVE NORMAL BOTH DAYS WITH
HIGHS IN THE 50S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1047 PM MST THU MAR 1 2012
BULK OF PRECIP NOW RESIDE SOUTHWEST OF KGLD AND ANTICIPATE THIS
TREND WILL CONTINUE. SHOULD SEE VFR CONDITIONS AT BOTH KGLD AND
KMCK THROUGH THE EFFECTIVE PERIOD. WINDS WILL BE VARIABLE
OVERNIGHT BEFORE BECOMING ESTABLISHED FROM THE NORTHWEST DURING
THE DAY FRIDAY. COULD SEE A FEW GUSTS APPROACHING 30KTS BEFORE
SUBSIDING AROUND SUNSET. BKN-OVC MID-LEVEL CLOUD DECK WILL SLOWLY
ERODE ON FRIDAY.
&&
.FIRE WEATHER...
ISSUED AT 200 PM MST THU MAR 1 2012
CRITICAL FIRE WEATHER CONDITIONS REMAIN POSSIBLE ALONG AND SOUTH
OF INTERSTATE 70 SATURDAY AS NORTHWEST WINDS OF 15 TO 25 MPH WITH
HIGHER GUSTS COMBINE WITH AFTERNOON HUMIDITY AS LOW AS 20 PERCENT.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
KS...NONE.
NE...NONE.
&&
$$
UPDATE...FOLTZ
SHORT TERM...DR
LONG TERM....007
AVIATION...FOLTZ
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1118 PM CST THU MAR 1 2012
...UPDATE TO AVIATION FOR 06Z TAFS...
.SHORT TERM...(THIS EVENING THROUGH TOMORROW)
ISSUED AT 125 PM CST THU MAR 1 2012
THE MAIN FORECAST FOCUS WILL BE ON THE CHANCE FOR PRECIP LATE
TONIGHT.
SHORT RANGE MODELS INDICATE THE UPPER LEVEL SHORTWAVE IN THE WESTERN
NORTHERN PLAINS TRACKING SLOWLY EAST INTO THE DAKOTAS TONIGHT THEN
EDGING INTO MINNESOTA FRIDAY. MEANWHILE, THE SECONDARY UPPER LEVEL
SHORTWAVE WILL CONTINUE TO DROP SOUTHEAST TONIGHT MOVING INTO THE
FOUR CORNERS REGION BY EARLY FRIDAY MORNING. THESE TWO FEATURES WILL
BRING THE POSSIBILITY FOR PRECIP ACROSS PORTIONS OF THE NORTHERN
PLAINS AND FROM ACROSS THE ROCKIES INTO THE WESTERN HIGH PLAINS
TONIGHT INTO EARLY FRIDAY. HOWEVER, NO PRECIP IS EXPECTED ACROSS
WESTERN KANSAS EARLY THIS EVENING WITH THE INITIAL PASSING OF THE
COLD FRONT ACROSS SOUTHWEST AND SOUTH CENTRAL KANSAS NOT TO
MENTION THE WEAK DYNAMIC SUPPORT ALOFT AND STRONG LACK OF LOW
LEVEL MOISTURE. HOWEVER, THERE IS A SLIGHT CHANCE FOR PRECIP LATE
TONIGHT INTO EARLY FRIDAY ACROSS EXTREME WESTERN PORTIONS OF
WESTERN KANSAS AS THE SECONDARY UPPER LEVEL SHORTWAVE DIPS
SOUTHEAST INTO THE FOUR CORNERS REGION. THE NAM, GFS, AND UKMET
SHOW A SERIES OF H5 VORT MAXES EJECTING NORTHEAST OUT OF THE
TROUGH AXIS ACROSS THE PANHANDLES OF TEXAS AND OKLAHOMA INTO
SOUTHWEST KANSAS TONIGHT JUST AS A BAND OF H7 FRONTOGENESIS
DEVELOPS BEHIND THE FRONT ACROSS SOUTHEAST COLORADO INTO WESTERN
KANSAS. AS A RESULT, LIGHT RAIN OR SNOW WILL BE POSSIBLE FROM
ACROSS EASTERN COLORADO AND POTENTIALLY JUST INTO EXTREME WESTERN
KANSAS LATE TONIGHT. HOWEVER, LITTLE ACCUMULATION IS EXPECTED, IF
ANY, WITH ONLY MODEST MOISTURE AVAILABLE IN THE MID AND UPPER
LEVELS AS INDICATED BY LOW QPF VALUES IN ALL MODELS.
TEMPERATURES ARE EXPECTED TO BE NEAR SEASONAL TONIGHT AS MUCH COLDER
AIR SURGES SOUTH INTO WESTERN KANSAS TONIGHT IN WAKE OF A COLD
FRONTAL PASSAGE LATE THIS AFTERNOON AND EVENING. COLD AIR ADVECTION
WILL BRING H85 TEMPERATURES OF AROUND TO JUST BELOW 0C DOWN INTO
SOUTHWEST AND SOUTH CENTRAL KANSAS BY EARLY FRIDAY MORNING. ALTHOUGH
INCREASING CLOUDS DUE TO THE APPROACHING STORM SYSTEM COULD HELP
KEEP TEMPERATURES FROM FALLING AS MUCH. LOOK FOR LOWS DOWN INTO THE
20S(F) TO LOW 30S(F) TONIGHT. FOR FRIDAY, A STRENGTHENING SURFACE
LOW ACROSS KANSAS TONIGHT WILL KICK OFF TO THE EAST FRIDAY JUST AS
SURFACE HIGH PRESSURE BEGINS TO BUILD IN ACROSS THE NORTHERN ROCKIES.
THIS WILL CONTINUE TO INFLUENCE A LOW LEVEL NORTHERLY FLOW INTO
WESTERN KANSAS THROUGH THE DAY HELPING TO KEEP H85 TEMPERATURES OF
AROUND 0C IN PLACE. LINGERING CLOUDS MAY TEMPER TEMPERATURES A BIT
BUT SO EXPECT HIGHS UP INTO THE 40S(F) WITH A FEW LOW 50S(F)
POSSIBLE IN SOME LOCATIONS.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 216 PM CST THU MAR 1 2012
AN UPPER LEVEL LONG WAVE TROUGH WILL BE FOUND ACROSS THE EASTERN TWO
THIRDS OF THE UNITED STATES AS THE LONG TERM PERIOD BEGINS. THIS
UPPER LEVEL TROUGH WILL MOVE TO THE EAST FRIDAY NIGHT THROUGH MONDAY
AS AN UPPER LEVEL RIDGE MOVES INTO THE WESTERN UNITED STATES. THIS
WILL PUT WESTERN KANSAS UNDER NORTHWEST FLOW ALOFT SATURDAY THROUGH
MONDAY. HIGH PRESSURE WILL BE THE DOMINATE FEATURE AT THE SURFACE
AND PARTLY CLOUDY SKIES AND DRY CONDITIONS ARE EXPECTED ACROSS
WESTERN KANSAS DURING THIS TIME FRAME. WINDS IN THE LOWER LEVELS OF
THE ATMOSPHERE WILL BE FROM THE NORTHWEST SATURDAY THROUGH MONDAY
AND WILL TRANSLATE TO A GENERAL WARMING TREND DUE TO THE DOWNSLOPE
NATURE OF THE WINDS. HIGHS WILL START OUT AROUND 50 DEGREES ON
SATURDAY AFTERNOON THEN TO THE UPPER 60S BY MONDAY AFTERNOON. LOWS
WILL START OUT IN THE MID 20S SATURDAY MORNING AND IN THE MID 30S BY
MONDAY MORNING.
MODELS ARE THEN SUGGESTING AN UPPER LEVEL SHORTWAVE TO MOVE INTO THE
WEST COAST MONDAY INTO TUESDAY, THEN INTO THE INTERMOUNTAIN WEST ON
WEDNESDAY. THE UPPER LEVEL RIDGE WILL SHIFT EASTWARD TOWARDS THE MID
MISSISSIPPI VALLEY AS THIS SYSTEM APPROACHES PLACING OUT AREA UNDER
SOUTHWEST FLOW ALOFT. THIS SYSTEM WILL ALSO CAUSE LEE TROUGHING TO
DEVELOP AT THE SURFACE ACROSS EASTERN COLORADO SHIFTING WINDS TO THE
SOUTH TO SOUTHWEST. A SURFACE HIGH WILL BE POSITIONED ACROSS THE
SOUTHEAST UNITED STATES AND HELP PUSH GULF MOISTURE NORTH INTO THE
CENTRAL PLAINS. CLOUDS ARE FORECAST TO INCREASE WEDNESDAY AS THE
AFOREMENTIONED STORM SYSTEM APPROACHES. EXTENDED MODELS ARE
SUGGESTING THAT THERE COULD BE ENOUGH MOISTURE AND LIFT ACROSS THE
AREA TO PRODUCE PRECIPITATION WEDNESDAY NIGHT BUT HAVE ONLY PLACED A
SLIGHT CHANCE OF POPS IN THE GRIDS TO REFLECT THIS. A SLIGHT COOLING
TREND IS ANTICIPATED MONDAY THROUGH WEDNESDAY AS LOWS ARE FORECAST
TO BE IN THE LOWER 40S THURSDAY AND FRIDAY MORNING WITH UPPER 30S BY
THURSDAY MORNING. HIGHS WILL BE IN THE LOWER 70S TUESDAY THEN IN THE
60S WEDNESDAY AND THURSDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1102 PM CST THU MAR 1 2012
LATEST HRRR/NAM SHOW THAT THIS PRECIP EVENT PROBABLY WILL HAVE SIG IMPACTS
TO AVIATION. FRCST COMP REFLECTIVITY FROM THE HRRR IS NOT THAT IMPRESSIVE
NOR IS QPF AMOUNTS. HAVE -SN FOR KGCK/KHYS AS THESE TERMINALS WILL BE
CLOSER TO THE 700 HPA BAROCLINIC ZONE/TROUGH AND WITHIN A ZONE OF HIGHER
OMEGA/ISEN LIFT. KHYS MIGHT SEE A REDUCTION TO MVFR CIGS THROUGH MORNING,
HOWEVER, CIGS WILL GENERALLY REMAIN VFR WHICH IS FORECAST BY THE HRRR.
VERY COLD AIR 500 HPA AROUND -33DEGC WILL SPREAD OVER W KS IN ASSOCIATION
WITH AN UL TROUGH SO CUMULUS BUILDUPS ARE POSSIBLE LATER TODAY.
&&
.FIRE WEATHER...
ISSUED AT 345 AM CST THU MAR 1 2012
ADIABATIC COMPRESSIONAL WARMING VIA MIXING TO NEAR 550 HPA AND DOWNSLOPE
WESTERLY WINDS AHEAD OF A COLD FRONT WILL LEAD TO CRITICAL FIRE WEATHER
CONDITIONS TODAY ACROSS FAR SW KANSAS. AS A RESULT, HAVE ISSUED AN RFW
FOR EXTREME SOUTHWEST KANSAS TODAY NEAR THE COLORADO AND OKLAHOMA STATE
BORDERS. SEE TOPRFWDDC FOR SPECIFIC DETAILS ON THIS HAZARD.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 28 50 25 51 / 20 20 10 10
GCK 27 45 23 50 / 30 20 10 10
EHA 27 43 22 50 / 20 20 10 10
LBL 27 48 24 51 / 10 20 10 10
HYS 28 47 24 50 / 30 20 10 10
P28 33 53 29 53 / 10 10 0 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...JJOHNSON
SHORT TERM...JJOHNSON
LONG TERM....HOVORKA 42
AVIATION...SUGDEN
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
332 AM CST FRI MAR 2 2012
.DISCUSSION...
A TROUGH OF LOW PRESSURE CURVES SOUTHWARD ACROSS EASTERN MN EARLY
THIS MORNING FROM A LOW PRESSURE CENTER IN EASTERN NORTH DAKOTA.
CLEARING HAS PROGRESSED TO NEAR A KLXL TO KFRM LINE. THE DRY WEDGE
IS WELL DEFINED IN SHORT TERM MODEL GUIDANCE AND WILL PUSH INTO
THE EASTERN CWA THIS MORNING. SOME MID/HIGH LEVEL CLOUDINESS WILL
BE STREAMING NORTHEASTWARD ACROSS SE MN AND WEST CENTRAL WI TODAY...
KEEPING IT PARTLY TO MOSTLY CLOUDY IN THESE AREAS. SOME SUNSHINE
TODAY SHOULD AID IN HIGHS REACHING 33 TO 38 DEGREES FROM WEST TO
EAST.
THE LOW IN EASTERN ND WILL BE MOVING SE ACROSS THE CWA TONIGHT
AND EARLY SATURDAY. THALER QG AND ISENTROPIC ANALYSIS INDICATES
SOME SNOW WILL LIKELY OCCUR TONIGHT...ESPECIALLY ALONG THE LEADING
EDGE OF THE LOW LEVEL WAA. ACCUMULATIONS WILL BE MINOR AND LESS
THAN AN INCH. SOME LIGHT SNOW IS STILL POSSIBLE ON SATURDAY OVER
FAR EASTERN MN AND WEST CENTRAL WI WITH THE LOW LEVEL CYCLONIC
FLOW.
THERE REMAINS SOME SPREAD WITH THE TRACK OF A CLIPPER LIKE LOW
PRESSURE SYSTEM PASSING SOUTHEAST ACROSS THE EASTERN DAKOTAS/MN ON
SUNDAY. THE GEM AND ECMWF ARE PRETTY BULLISH ON PRECIP ACROSS THE
SOUTHWEST QUARTER OF MN WHILE THE NAM IS FARTHER EAST WITH THE
PRECIPITATION PASSING ACROSS THE TWIN CITIES. PUT MORE WEIGHT ON
THE SREF POPS FOR SUNDAY WHICH KEPT MUCH OF THE LIGHT SNOW FROM
WEST CENTRAL THROUGH SOUTH CENTRAL MN. PERHAPS AN INCH OF
ACCUMULATION IN THIS REGION.
THE LONGER TERM PORTION OF THE FORECAST STILL FEATURES A BIG WARM-UP
FROM MONDAY INTO WEDNESDAY. LITTLE ARGUMENT SEEN BETWEEN THE GFS
AND ECMWF IN THIS PERIOD. HOWEVER...BEYOND WEDNESDAY SOME CHANGES
WERE COLLABORATED ON INCLUDING HIGHS ON THURSDAY AS WELL AS
PRECIPITATION CHANCES. THE ECMWF AND GFS BECOME 180 DEGREES OUT OF
PHASE WITH REGARDS TO THE H5 HEIGHT FIELD BY THURSDAY WITH THE
ECMWF SHOWING A LARGE SCALE TROF VERSUS RIDGING ON THE GFS. ONE
THING THEY DO AGREE ON IS THAT WE SHOULD BE IN THE WAKE OF A
FRONTAL BOUNDARY AND POPS WERE REMOVED FOR THURSDAY. HIGH
TEMPERATURES FOR THURSDAY OF 45 TO 50 WERE LOWERED INTO THE 40-43
DEGREE RANGE.
&&
.AVIATION... /06Z TAF ISSUANCE/
BURST OF -SN OUT AHEAD OF SFC TROUGH ALREADY WORKING INTO WESTERN
WI. BASED ON DOWNSTREAM OBS...EXPECT 1 1/2SM -SN FOR 2-3 HRS TO
BEGIN THE TAF AT EAU. HAVE NOT SEEN MUCH FZDZ BEHIND THE
SN...INSTEAD...THERE HAS BEEN ABOUT 2 HRS OF IFR CIGS...FOLLOWED
BY 1-2 HRS OF MVFR CIGS BEFORE SKIES CLEAR OUT. TRIED TO TIME IFR
TO MVFR IMPROVEMENT AS BEST I COULD...BUT MAY BE HOLDING ON TO IFR
CIGS AT ERN TAF SITES A BIT TO LONG. RUC 925-850 RH HAS HAD A
GOOD HANDLE ON CLEARING WORKING THROUGH WRN MN THIS EVENING...SO
USED THAT TO TIME VFR CONDITIONS IN TO TERMINALS...AGAIN IF
ANYTHING HOLDING ON TO MVFR CIGS A LITTLE LONGER THAN THE RUC
WOULD INDICATE. ONLY QUESTION MARK WITH THE CLEARING IS AT
EAU...AS THE RUC DOES NOT TAKE WRLY FLOW THIS FAR EAST IN THE
MORNING...INDICATING THE STRATUS MAY BE LEFT HANGING OVER THERE.
SCT EAU OUT AT 017...BUT WILL HAVE TO SEE HOW THE CLEARING DOES.
MUCH OF FRIDAY LOOKS GOOD...WITH ONLY PASSING CIRRUS EXPECTED FROM
STRONG JET SCREAMING ACROSS THE SOUTH. WILL JUST HAVE TO TIME
RETURN OF STRATUS AS LOW CURRENTLY IN NODAK SWINGS INTO MN AND
BEGINS TO BE ABSORBED BY SRN STREAM ENERGY. GFS/NAM HAVE SIMILAR
TIMING WITH BRINGING THESE CIGS BACK THROUGH...SO CONFIDENCE
ACTUALLY FAIRLY HIGH ON TIMING OF STRATUS RETURN...HARDER TO SAY
WHAT LEVEL IT WILL BE AT THIS FAR OUT...BUT AT LEAST HIGH END MVFR
SEEMS CERTAIN. IN ADDITION TO THE CLOUDS COMING DOWN...BUFKIT
SOUNDING AND PRECIP FORECASTS FROM THE NAM/GFS WOULD SAY SNOW
SHOWERS WILL ACCOMPANY THE CLOUDS...SO INTRODUCED SOME PROB30S TO
ACCOUNT FOR THAT. FINALLY...SRN STREAM WAVE WILL SIGNIFICANTLY
STRENGTHEN AS IT MOVES INTO MICH FRIDAY EVENING...WITH NW WINDS
PICKING UP IN STRENGTH IN RESPONSE...WITH SOME PRETTY GOOD
SPEEDS/GUSTS INDICATED TO DEVELOP FRIDAY NIGHT.
KMSP...MAY SEE A BRIEF PERIOD OF FZDZ AS -SN PULLS OUT...BUT SUCH
OBS HAVE BEEN FEW AND FAR BETWEEN...SO HAVE NO MENTION IN TAF.
BASED ON OBS TO THE WEST...EXPECT IFR CIGS TO HANG ON FOR UP TO
TWO HOURS...BEFORE GOING UP TO SUB 017 MVFR. AFTER THAT...RUC HAS
HAD A GREAT HANDLE ON CLEARING WORKING INTO THE FIELD AROUND
10Z...SO HAVE THINGS GOING SCT THEN. HARD PRESSED TO FIND MUCH
CLOUD COVER OUTSIDE OF CIRRUS DURING THE DAY FRIDAY...SO
SIGNIFICANTLY IMPROVED GOING FORECAST UNTIL STRATUS RETURNS AFTER
00Z. ALSO LOOKS LIKELY THAT MUCH OF SATURDAY AFTER 06Z WILL SEE
BOUTS OF -SHSN.
//OUTLOOK...SATURDAY THROUGH TUESDAY...
.SAT-SUN...MVFR CIGS. -SHSN ENDING SAT EVENING.
.MON-TUE...VFR.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
RAH/MPG
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1211 AM CST FRI MAR 2 2012
.UPDATE...
06Z AVIATION DISCUSSION ADDED BELOW.
&&
.DISCUSSION...
SPLIT FORCING CROSSING THE AREA TONIGHT. ONE WAVE OVER NORTH
DAKOTA TO AFFECT MAINLY NORTHERN MN AND THE OTHER..SOMEWHAT LESS
DEFINED OVER EASTERN NEBRASKA. CLOUD TOPS NOW COOLING...AFTER A
SLIGHT DECREASE DURING THE MORNING...OVER SOUTHWEST MN AND
NORTHWEST IOWA. THIS AREAS OF ISEN LIFT AND WEAK FGEN MOVES INTO
SOUTH CENTRAL AND SOUTHEAST MINNESOTA THIS EVENING...ALTHOUGH THE
BETTER MID LEVEL THETA E ADVECTION REMAINS ACROSS IOWA. LATER IN
THE EVENING AND OVERNIGHT...THE GFS AND NAM HAVE BEEN CONSISTENT
IN THE LAST 2 RUNS IN BRINGING AN AREA OF THALER QG VERT VEL AND
AND INSTANTANEOUS PRECIP FIELDS MAINLY ACROSS CENTRAL AND PARTS OF
SOUTHERN MN. THIS DOES TEND TO WEAKEN AFTER MIDNIGHT BUT ENOUGH TO
BRING AREAS OF LIGHT SNOW ACROSS THE AREAS. WILL HOWEVER...TRY TO
NARROW DOWN THE LIKELY POPS TO OVER MAINLY THE MN CWA. SOME HINT
OF SLIGHT LIFT REMAINING AFTER THE HIGHER LAYER MOISTURE MOVES OUT
LATE TONIGHT INTRODUCED PATCHY LIGHT FZDZ. THE WAVE OVER THE
SOUTHERN ROCKIES APPEARS TO BE SLIDING TO OUR SOUTHEAST AND WILL
AFFECT EASTERN IOWA AND SOUTHERN WISCONSIN.
FOR THE REST OF THE WEEKEND A COUPLE OF OTHER CHANCES OF LIGHT
SNOW AND FLURRIES....ALTHOUGH THE MORE WIDESPREAD CHANCE WOULD BE
LATER FRIDAY NIGHT AND SATURDAY AS THE CIRCULATION OVER SOUTHERN
CANADA/MONTANA SLIDES SOUTHEAST OVER THE AREA. THIS WILL ALSO
BRING A BRIEF VISIT OF NEAR OR SLIGHTLY BELOW NORMAL TEMPS. THE
STRONG NORTHWEST UPPER JET WILL LIKELY BRING AN IMPULSE WITH A
WARM ADVECTION PATTERN ON SUNDAY...BUT SOME UNCERTAINTY IN WHERE
A NARROW BAND OF SNOW MAY SET UP.
THE SIGNIFICANT WARMING TREND LOOKS TO BE ON TRACK FOR TUESDAY
INTO WEDNESDAY. IT SURE LOOKS LIKE A POTENTIAL OF 55 TO 60. AS
IN THE PREVIOUS DISCUSSION EVEN MIXING FROM 925 MB YIELDS A
WIDE AREA OF 50S TO NEAR 60. LOOKS LIKE SOME POTENTIAL FOR
OVERRUNNING PRECIP ALONG THE TIGHT THICKNESS GRADIENT BEHIND THE
COLD FRONT WEDNESDAY INTO THURSDAY...BUT WILL FOLLOW THE BLENDED
LOWER POPS FOR NOW. IT ALSO LOOKS LIKE A SIGNAL FOR A POTENTIAL
PLAINS STORM SYSTEM LATE NEXT WEEK AS THE SPC SEVERE WEATHER
ANALOG SITE LIGHTING UP A BIT ABOUT MARCH 8-9.
&&
.AVIATION.../06Z TAF ISSUANCE/
BURST OF -SN OUT AHEAD OF SFC TROUGH ALREADY WORKING INTO WESTERN
WI. BASED ON DOWNSTREAM OBS...EXPECT 1 1/2SM -SN FOR 2-3 HRS TO
BEGIN THE TAF AT EAU. HAVE NOT SEEN MUCH FZDZ BEHIND THE
SN...INSTEAD...THERE HAS BEEN ABOUT 2 HRS OF IFR CIGS...FOLLOWED
BY 1-2 HRS OF MVFR CIGS BEFORE SKIES CLEAR OUT. TRIED TO TIME IFR
TO MVFR IMPROVEMENT AS BEST I COULD...BUT MAY BE HOLDING ON TO IFR
CIGS AT ERN TAF SITES A BIT TO LONG. RUC 925-850 RH HAS HAD A
GOOD HANDLE ON CLEARING WORKING THROUGH WRN MN THIS EVENING...SO
USED THAT TO TIME VFR CONDITIONS IN TO TERMINALS...AGAIN IF
ANYTHING HOLDING ON TO MVFR CIGS A LITTLE LONGER THAN THE RUC
WOULD INDICATE. ONLY QUESTION MARK WITH THE CLEARING IS AT
EAU...AS THE RUC DOES NOT TAKE WRLY FLOW THIS FAR EAST IN THE
MORNING...INDICATING THE STRATUS MAY BE LEFT HANGING OVER THERE.
SCT EAU OUT AT 017...BUT WILL HAVE TO SEE HOW THE CLEARING DOES.
MUCH OF FRIDAY LOOKS GOOD...WITH ONLY PASSING CIRRUS EXPECTED FROM
STRONG JET SCREAMING ACROSS THE SOUTH. WILL JUST HAVE TO TIME
RETURN OF STRATUS AS LOW CURRENTLY IN NODAK SWINGS INTO MN AND
BEGINS TO BE ABSORBED BY SRN STREAM ENERGY. GFS/NAM HAVE SIMILAR
TIMING WITH BRINGING THESE CIGS BACK THROUGH...SO CONFIDENCE
ACTUALLY FAIRLY HIGH ON TIMING OF STRATUS RETURN...HARDER TO SAY
WHAT LEVEL IT WILL BE AT THIS FAR OUT...BUT AT LEAST HIGH END MVFR
SEEMS CERTAIN. IN ADDITION TO THE CLOUDS COMING DOWN...BUFKIT
SOUNDING AND PRECIP FORECASTS FROM THE NAM/GFS WOULD SAY SNOW
SHOWERS WILL ACCOMPANY THE CLOUDS...SO INTRODUCED SOME PROB30S TO
ACCOUNT FOR THAT. FINALLY...SRN STREAM WAVE WILL SIGNIFICANTLY
STRENGTHEN AS IT MOVES INTO MICH FRIDAY EVENING...WITH NW WINDS
PICKING UP IN STRENGTH IN RESPONSE...WITH SOME PRETTY GOOD
SPEEDS/GUSTS INDICATED TO DEVELOP FRIDAY NIGHT.
KMSP...MAY SEE A BRIEF PERIOD OF FZDZ AS -SN PULLS OUT...BUT SUCH
OBS HAVE BEEN FEW AND FAR BETWEEN...SO HAVE NO MENTION IN TAF.
BASED ON OBS TO THE WEST...EXPECT IFR CIGS TO HANG ON FOR UP TO
TWO HOURS...BEFORE GOING UP TO SUB 017 MVFR. AFTER THAT...RUC HAS
HAD A GREAT HANDLE ON CLEARING WORKING INTO THE FIELD AROUND
10Z...SO HAVE THINGS GOING SCT THEN. HARD PRESSED TO FIND MUCH
CLOUD COVER OUTSIDE OF CIRRUS DURING THE DAY FRIDAY...SO
SIGNIFICANTLY IMPROVED GOING FORECAST UNTIL STRATUS RETURNS AFTER
00Z. ALSO LOOKS LIKELY THAT MUCH OF SATURDAY AFTER 06Z WILL SEE
BOUTS OF -SHSN.
//OUTLOOK...SATURDAY THROUGH TUESDAY...
.SAT-SUN...MVFR CIGS. -SHSN ENDING SAT EVENING.
.MON-TUE...VFR.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
JPR/MPG
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
400 AM EST FRI MAR 2 2012
.SYNOPSIS...
A STATIONARY FRONT WILL LIFT NORTH AS A WARM FRONT THIS
MORNING. A STRONG COLD FRONT WILL BRING THUNDERSTORMS SATURDAY
AFTERNOON AND EVENING. COOLER AND DRIER HIGH PRESSURE WILL BUILD
INTO THE AREA EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 330 AM FRIDAY...A NEARLY STATIONARY FRONT EXTENDING EAST-WEST
FROM AROUND NEW BERN TO NEAR KINSTON...TO FAYETTEVILLE...SOUTHERN
PINES...WADESBORO AND MONROE...WILL MOVE LITTLE THROUGH DAYBREAK.
THE BOUNDARY WILL JUMP NORTH LATER THIS MORNING WITH SOUTHERLY WINDS
BRINGING SUBTROPICAL MOISTURE ACROSS ALL OF NORTH AND SOUTH
CAROLINA. A WEAK UPPER DISTURBANCE WILL CROSS THE AREA LATE THIS
MORNING JUST BEHIND THE RETREATING FRONT BRINGING THE POTENTIAL FOR
SCATTERED SHOWERS OR THUNDERSTORMS TO MAINLY THE INLAND PORTIONS OF
THE CAROLINAS. THE DISTURBANCE WILL HELP COOL THE 700 MB TEMP JUST
ENOUGH TO ERODE A CONVECTIVE CAP ALLOWING SOME ELEVATED CONVECTION
TO OCCUR. THE LAST FEW RUNS OF THE HRRR HIGH-RESOLUTION MESOSCALE
MODEL SHOW A CONVECTIVE CHARACTER TO FORECAST PRECIPITATION ECHOES
ACROSS THE CENTRAL CAROLINAS IN THE 14-17Z TIME FRAME. PRECIPITATION
CHANCES WILL DROP TO LESS THAN 10 PERCENT BY MID-AFTERNOON AS THE
DISTURBANCES SWINGS BY TO THE NORTHEAST.
TONIGHT WARM AND MOIST SOUTH-SOUTHWESTERLY FLOW WILL CONTINUE OUT
AHEAD OF A STRONG COLD FRONT ADVANCING STEADILY EASTWARD. SHOWERS
AND THUNDERSTORMS ALONG THE FRONT WILL REACH THE PEE DEE REGION
LATE...PROBABLY AROUND 4 AM...AND MAY REACH THE COAST AROUND SUNRISE
SATURDAY MORNING. ALTHOUGH THIS IS THE SAME SYSTEM ANTICIPATED TO
BRING A LARGE SEVERE WEATHER OUTBREAK TO PORTIONS OF THE MID-SOUTH
AND TENNESSEE/OHIO VALLEYS TODAY...THE SYNOPTIC SITUATION IS NOT
QUITE AS FAVORABLE THIS FAR EAST SINCE THE PARENT UPPER DISTURBANCE
WILL BE SHEARING OUT TO THE NORTHEAST. THE LATE-NIGHT TIMING COUPLED
WITH COLD NEARSHORE OCEAN WATER TEMPERATURES ARE ALSO UNFAVORABLE
FACTORS FROM THE STANDPOINT OF MAINTAINING STRONG SURFACE-BASED
CONVECTION.
HIGHS TODAY SHOULD RANGE FROM THE MID 70S ACROSS MOST OF
SOUTHEASTERN NORTH CAROLINA...TO NEAR 80 ACROSS THE PEE DEE REGION
OF SOUTH CAROLINA. MUCH LIKE YESTERDAY WINDS BLOWING ONSHORE FROM
THE COLD NEARSHORE OCEAN WILL KEEP TEMPERATURES A GOOD 10-15 DEGREES
COLDER THAN INLAND AREAS. TONIGHT LOWS SHOULD ONLY FALL INTO THE
LOWER 60S WITH A STEADY SOUTH-SOUTHWEST WIND CONTINUING.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 330 AM FRIDAY...LATEST FORECAST SOUNDINGS SUGGEST THIS
WEEKENDS RAIN EVENT COULD BRING SIGNIFICANT RAINFALL TO THE
REGION. YESTERDAY SOUNDINGS WERE SHOWING A BRIEF PERIOD THE
ATMOSPHERE WAS NEARLY SATURATED. HOWEVER THE LATEST GUIDANCE IS
MUCH WETTER. IT NOW LOOKS LIKE THE FRONT WILL DROP INTO THE AREA
SAT MORNING THEN STALL AS THE FRONT ENDS UP LAYING PARALLEL TO THE
FLOW ALOFT. EARLIER SOLUTIONS HAD THE FRONT STALLING OFF THE
COAST...A SOLUTION WHICH STILL COULD COME TO PASS. SPC HAS PUT
MOST OF THE FORECAST AREA INTO THE DAY 2 SLIGHT RISK...BUT THREAT
APPEARS LIMITED. FIRST THERE WILL BE CONSIDERABLE CLOUD COVER
ACROSS THE AREA SAT...LIMITING DIURNAL HEATING. MID LEVEL LAPSE
RATES ARE MARGINAL AT BEST MOSTLY UNDER 6C/KM. LOW LEVEL JETTING
IN FORECAST SOUNDINGS IS WEAKER THAN IN PREVIOUS RUNS. STRONG
SOUTHWEST FLOW WILL PUSH TEMPERATURES INTO THE LOW 70S DESPITE
CLOUDS AND PRECIP.
SURFACE WAVE DEVELOPS ALONG THE FRONT LATE SAT INTO SAT NIGHT SOUTH
OF THE AREA THEN TRACKS NORTHEAST ALONG THE FRONT BRINGING ANOTHER
ROUND OF SHOWERS AND ISOLATED THUNDERSTORMS TO THE REGION SAT NIGHT
INTO SUN. 5H TROUGH MOVES INTO THE AREA EARLY SUN...PUSHING THE
FRONT...ALONG WITH ANY ASSOCIATED PRECIP...OFF THE COAST. ARRIVAL
TIME OF COLD AIR SAT NIGHT WILL BE KEY TO DETERMINING HOW LOW TEMPS
DROP. SOME LIGHT PRECIP MAY LINGER INTO SUN MORNING BUT OVERALL SUN
SHOULD BE DRY WITH SKIES CLEARING DURING THE DAY. COLD ADVECTION
WILL KEEP TEMPS BELOW CLIMO SUN AND SUN NIGHT. HOWEVER BOUNDARY
LAYER REMAINS WELL MIXED SUN NIGHT...PREVENT TEMPS FROM DROPPING
BELOW FREEZING.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 330 AM FRIDAY...5H TROUGH WILL BE IN THE PROCESS OF LIFTING
NORTHEAST AT THE START OF THE PERIOD. DRY COLD FRONT MOVES ACROSS
THE REGION EARLY MON BUT ALL IT WILL BRING IS A REINFORCING SHOT
OF COOLER AIR LATER IN THE DAY. INCREASE IN CLOUD COVER MON
ASSOCIATED THIN LAYER OF MOISTURE BETWEEN 850 AND 750 MB IN
CONJUNCTION WITH A SHORTWAVE ROTATING AROUND THE BASE OF THE UPPER
TROUGH. PRECIP IS NOT AN ISSUE AS MOISTURE IS NOT NEARLY DEEP
ENOUGH. REMAINDER OF THE PERIOD WILL REMAIN DRY WITH VERY LITTLE
IN THE WAY OF CLOUDS. TEMPERATURES BOTTOM OUT MON NIGHT INTO
TUE...WITH LOWS MON NIGHT AT OR BELOW FREEZING AND HIGHS TUE IN
THE MID 50S. ELONGATED RIDGE AXIS SHIFTS OFFSHORE TUE NIGHT WITH
LIGHT ONSHORE FLOW DEVELOPING. ECMWF/GFS BOTH SHOW WEAK COASTAL
TROUGH DEVELOPING TUE NIGHT BUT BOTH MOVE THIS FEATURE ONSHORE
WED. AT THIS POINT TROUGH LOOKS TOO WEAK TO SUPPORT PRECIP. 5H
RIDGE BUILDS OVER THE SOUTHEAST WED THEN STRENGTHENS FOR THU.
TEMPERATURES RETURN CLOSE TO CLIMO WED/WED NIGHT...RUNNING NEAR TO
SLIGHTLY ABOVE CLIMO THU/THU NIGHT.
&&
.AVIATION /09Z FRIDAY THROUGH TUESDAY/...
AS OF 06Z...A NEARLY STATIONARY FRONT ACROSS SOUTH-CENTRAL NORTH
CAROLINA WILL WAVE BACK NORTH AS A WARM FRONT LATER THIS MORNING.
MODELS SHOW WINDS WITHIN THE BOUNDARY LAYER DROPPING OFF QUITE
RAPIDLY AFTER 07Z. IFR CEILINGS/VIS ARE LIKELY TO DEVELOP. AS MID
AND HIGH CLOUDS OVERSPREAD THE REGION...THE THREAT OF FOG MAY
DIMINISH...ALTHOUGH HIGHER DEWPOINTS AND COOL OCEAN AND SOIL TEMPS
REMAIN POSITIVES FOR FOG FORMATION. THIS AFTERNOON WINDS WILL SHIFT
FROM SOUTHEASTERLY TO SOUTHWESTERLY...AND GUSTY THIS AFTERNOON.
MODELS HINTING AT STRATUS RETURNING TOWARD THE END OF THE FORECAST
PERIOD...BUT LOW CONFIDENCE.
EXTENDED OUTLOOK...THUNDERSTORMS/TEMPO IFR SATURDAY THROUGH SUNDAY
MORNING. OTHERWISE VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 330 AM FRIDAY...A FRONT STALLED OUT ACROSS INLAND SOUTHERN
NORTH CAROLINA WILL RETREAT FARTHER NORTH TODAY...OPENING UP THE
FLOODGATES FOR SUSTAINED SOUTHERLY WINDS TODAY INTO TONIGHT. MUCH
LIKE YESTERDAY...THE HUMID SUBTROPICAL AIRMASS WILL BECOME CHILLED
BY ITS JOURNEY ACROSS THE COLD NEARSHORE OCEAN WATERS AND COULD
YIELD LOW STRATUS CLOUDS OR PATCHY SEA FOG AT TIMES. SOUTH WINDS
WILL INCREASE TO AROUND 15 KT THIS AFTERNOON...AND THEN TO 20 KNOTS
TONIGHT. THESE SURFACE WIND SPEEDS SHOULD BE LIMITED BY A STABLE
BOUNDARY LAYER FROM THE COLD UNDERLYING OCEAN SURFACE. GO 30-40
MILES OFFSHORE WHERE WATER TEMPERATURES ARE WARMER...AND WIND SPEEDS
WILL EASILY BE ANOTHER 5-10 KNOTS HIGHER WITH MUCH ROUGHER SEAS TOO.
THE FRYING PAN SHOALS BUOY IS REPORTING 4-5 FT SEAS OVER THE PAST
COUPLE OF HOURS. SEAS WITHIN 20 MILES OF SHORE SHOULD AVERAGE 3 FT
TODAY...BUILDING TO 4-6 FT OVERNIGHT...HIGHEST IN THE FRYING PAN
SHOALS VICINITY.
SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 330 AM FRIDAY...INCREASING SOUTHWEST FLOW AHEAD OF A STRONG
COLD FRONT WILL REQUIRE A SCA HEADLINE AT SOME POINT SAT. SPEEDS
START OUT 15 TO 20 KT BUT INCREASE TO 20 TO 25 KT SAT
AFTERNOON/EVENING AS GRADIENT TIGHTENS UP. PROLONGED SOUTHWEST
FLOW WILL PROBABLY BUILD SEAS OVER 6 FT BEFORE SPEEDS REACH 25 KT.
DURATION OF SCA MAY END UP BEING RATHER BRIEF. THE FRONT WILL
STALL ALONG OR JUST OFF THE COAST WITH AN ILL-DEFINED PRESSURE
PATTERN KEEPING WINDS VARIABLE WITH SPEEDS BETWEEN 10 AND 15 KT.
WEAK WAVE OF LOW PRESSURE MOVES NORTHEAST ALONG THE STALLED
BOUNDARY PASSING EAST OF THE WATERS LATE SAT NIGHT. GRADIENT
TIGHTENS UP SUN AS THE LOW/FRONT MOVES EAST-NORTHEAST AND COLD
ADVECTION ARRIVES. STRONG OFFSHORE FLOW MAY WARRANT A BRIEF
DURATION HEADLINE SUN NIGHT INTO MON.
LONG TERM /MONDAY THROUGH TUESDAY/...
AS OF 330 AM FRIDAY...OFFSHORE FLOW WILL SLOWLY DECREASE ON MON AS
ELONGATED HIGH PRESSURE OVER THE MISSISSIPPI VALLEY SHIFTS EAST.
SPEEDS START OUT 15 TO 20 KT FROM THE WEST-NORTHWEST BUT DROP TO
10 TO 15 KT LATE MON NIGHT INTO TUE AS THEY BACK TO NORTH-
NORTHEAST. SEAS RUNNING 3 TO 5 FT DUE TO STRONG OFFSHORE FLOW WILL
SUBSIDE TO 2 TO 4 FT LATE MON INTO MON NIGHT.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...TRA
SHORT TERM...III
LONG TERM...III
AVIATION...43/TRA
AREA FORECAST DISCUSSION
NWS PORTLAND OR
908 PM PST THU MAR 1 2012
.SYNOPSIS...SHOWERS DECREASING...AND SNOW LEVELS ARE SLOWLY RISING.
WARM FRONT WILL BUCKLE ACROSS REGION FRI WITH SPOTTY RAIN MAINLY
NORTH. HIGH PRES BUILDS OVER S OREGON THIS WEEKEND...WITH CLOUDS
DECREASING AND PRECIP RETREATING TO N BACK INTO WASHINGTON. DRY
WEATHER WILL END EARLY NEXT WEEK AS RAIN RETURNS ON MON.
&&
.SHORT TERM...STILL A FEW SHOWERS AROUND...SOME THAT HAD A BIT OF
SMALL HAIL/GRAUPEL IN THEM EARLIER THIS EVENING...THAT FORMED ALONG A
CONVERGENCE BOUNDARY ALONG THE OREGON/WASHINGTON BORDER. RUC SUGGESTS
SHOWERS SHOULD EASE QUICKLY AFTER 6Z...THOUGH ONSHORE FLOW CONTINUES
AND EXPECT WE`LL SEE SOME PESKY SHOWERS CONTINUE AFTER MIDNIGHT
GENERALLY FROM PORTLAND/VANCOUVER EAST...THOUGH COVERAGE DECREASES.
WE MAY ALSO SEE ISOLATED RAIN SNEAKING BACK INTO THE COAST AHEAD OF
THE OFFSHORE WARM FRONT OVERNIGHT. WITH BREAKS IN CLOUD COVER AND A
VERY MOIST AIR MASS WITH THE AIR MASS STABILIZING...PATCHY FOG IS
POSSIBLE...THOUGH STRATUS LOOKS MORE LIKELY. BETTER THREAT OF FOG
LIES ACROSS S HALF OF WILLAMETTE VALLEY. TEMPS NEAR FREEZING WILL
HAVE TO WATCH FOR AREAS OF BLACK ICE FRI AM. GUIDANCE KEEPS MOST
AREAS IN THE VALLEY ABOVE FREEZING AND HAVE NUDGED TEMPS UP A
BIT...THOUGH AREAS WITH MORE CLEARING WILL BE PRONE TO THE COOLER
TEMPS
EARLY MODELS SUGGESTED WARM FRONT HUNG UP OVER PAC NW THIS
WEEKEND...BUT NOW APPEARS THIS NOT THE CASE. WARM FRONT BUCKLES
ACROSS REGION ON FRI NIGHT AND SAT...WITH LIGHT RAIN OVER REGION
ESPECIALLY N OF A NEWPORT TO SANTIAM PASS LINE. AS HIGH PRES BUILDS
OVER S OREGON AND N CALIF THIS WEEKEND...SHOULD SEE RAIN THREAT
DECREASING RAPIDLY ON SAT...THEN DRY WEATHER WITH MIX OF SUN AND
CLOUDS FOR SAT AFTERNOON THROUGH SUN. HAVE ADJUSTED FORECASTS TO SHOW
DRIER AND MILDER WEATHER FOR THIS WEEKEND. KMD/ROCKEY.
.LONG TERM...THE NEXT SYSTEM APPROACHES LATE SUNDAY NIGHT AND SHOULD
BRING ANOTHER ROUND OF RAIN AND MOUNTAIN SNOW DURING THE DAY MONDAY.
SHOWERS SHOULD CONTINUE ACROSS THE AREA IN THE WAKE OF THIS SYSTEM
INTO TUESDAY. AN UPPER LEVEL TROUGH OVER THE NE PACIFIC WILL BRING
PERIODS OF SHOWERS THROUGH THE WEEK...BUT MODEL CONSENSUS IS POOR ON
THE EVOLUTION OF THIS PATTERN. HAVE KEPT THE FORECAST LEANING
TOWARDS CLIMATOLOGY TUESDAY AND BEYOND. BROWN
&&
.AVIATION...SHOWERS ON THE DECREASE THIS EVENING WITH MAINLY VFR
CONDITIONS. MAY SEE SOME LOW MVFR TO IFR CONDITIONS IN FOG
ESPECIALLY SOUTH OF KSLE LATER TONIGHT AS THE MOIST AIR MASS
STABILIZED A BIT. NORTH OF KSLE MAY BE MORE MVFR CIGS WHERE
ONSHORE FLOW CONTINUES.
KPDX AND APPROACHES...MOSTLY VFR CONDITIONS WITH OCCASIONAL MVFR
THIS EVENING...THEN INCREASING CHANCES FOR MVFR CIGS AROUND 1500
FEET AFTER 11Z. PATCHY FOG 2-3SM ALSO POSSIBLE IN THE VICINITY OF
KPDX.
&&
.MARINE...NW SWELL TRAIN CONTINUES TO SUBSIDE. SEAS RUNNING
AROUND 10 TO 12 FT...ABOUT A FOOT OR 2 BELOW GUIDANCE. SO
HAZARDOUS SEAS ADVISORY MAY END SEVERAL HOURS EARLIER THAN CURRENT
FORECAST.
A WEAK FRONT MOVING THROUGH ON FRIDAY WILL BRIEFLY GIVE US
ADVISORY LEVEL WINDS. HIGH PRES WILL BRING FAIRLY CALM CONDITIONS
BACK OVER THE WATERS SATURDAY...BEFORE ANOTHER WEAK FRONT MOVES
THROUGH SUNDAY NIGHT.
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 10 AM PST
FRIDAY FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO
FLORENCE OR OUT 60 NM.
SMALL CRAFT ADVISORY FOR WINDS FROM 7 AM PST
TO 4 PM PST FRIDAY FOR COASTAL WATERS FROM CAPE SHOALWATER WA
TO FLORENCE OR OUT 60 NM.
SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL
1 AM PST FRIDAY.
SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR FROM
10 AM TO 2 PM PST FRIDAY.
&&
$$
MORE WEATHER INFORMATION ONLINE AT...
HTTP://WEATHER.GOV/PORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM
THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY
REFERRED TO AS THE FORECAST AREA.
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1150 PM CST THU MAR 1 2012
UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND FRIDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW LOW PRESSURE
MOVING OVER THE EASTERN GREAT LAKES...BUT WITH SURFACE TROUGHING
EXTENDING WEST INTO NORTHERN WISCONSIN. THE COMBO OF WEAK CYCLONIC
FLOW AND THERMAL TROUGHING IN THE LOW LEVELS HAS LEAD TO A ROBUST
STRATUS DECK THAT HAS HELD FIRM THROUGH EARLY THIS AFTERNOON. SOME
HOLES IN THE CLOUDS HAVE TRIED TO DEVELOP OVER THE LAKESHORE WITHOUT
MUCH LUCK. MEANWHILE...PLENTY OF INCOMING CONCERNS UPSTREAM.
NORTHERN STREAM SHORTWAVE IS SLOWLY MOVING EAST OVER THE
MONTANA/N.D. BORDER WITH LIGHT SNOW SPREADING ACROSS N.D. FARTHER
SOUTH...WEAK SHORTWAVE IMPULSES ARE MOVING WITHIN FAST SW FLOW OVER
THE CENTRAL PLAINS. ONE DISTURBANCE IS PRODUCING LIGHT SNOW OVER NE
NEBRASKA AND NW IOWA. FINALLY...THE STRONGEST SHORTWAVE IS RAPIDLY
MOVING EAST OVER UTAH/COLORADO...AND SNOW AMOUNTS/HEADLINES WITH
THIS FEATURE WILL BE THE MAIN FORECAST CONCERN.
TONIGHT...NORTHERN STREAM SHORTWAVE WILL MOVE ACROSS NORTH DAKOTA
INTO MINNESOTA AND PUSH AN UPPER LEVEL FRONT INTO NORTHWEST
WISCONSIN LATE TONIGHT. FORCING IS PRETTY WEAK...BUT GUIDANCE IS
OPTIMISTIC ABOUT GENERATING LIGHT SNOW ALONG IT. UPSTREAM OBS SNOW
THE POTENTIAL FOR LIGHT SNOW...SO WILL KEEP IT IN THE FORECAST AFTER
06Z. MEANWHILE...RELATIVELY WEAKER SOUTHERN STREAM IMPULSES WILL
RACE NORTHEAST INTO THE WESTERN GREAT LAKES. LIGHT SNOW OVER NE
NEBRASKA MAY MAKE A RUN AT CENTRAL OR EAST-CENTRAL WISCONSIN LATE AS
WELL. CONFIDENCE NOT QUITE AS HIGH WITH THIS FEATURE AS THE ONE
FARTHER NORTH...SO WILL SHOW LOWER POPS. NOT EXPECTING MUCH ACCUMS
WITH EITHER FEATURE THOUGH...PERHAPS A COUPLE TENTHS.
OTHERWISE...ANTICIPATE THE BACK EDGE OF THE LOW STRATUS WILL
ACCELERATE NORTHEAST OVER THE NORTHERN MISSISSIPPI VALLEY EARLY
TONIGHT. LOW LEVEL WIND FIELDS BECOME WEAK SO THINK THE LOW
OVERCAST WILL HANG AROUND. IF THEY DO CLEAR OVER CENTRAL AND
EAST-CENTRAL WISCONSIN (HIGHEST PROBABILITY)...MID AND HIGH CLOUDS
WILL KEEP THE SKIES OVERCAST. LOWS IN THE MID 20S TO THE LOWER 30S.
FRIDAY...CENTRAL ROCKIES SHORTWAVE WILL BE MOVING ACROSS THE CENTRAL
PLAINS AND NORTHEAST OVER THE MID-MISSISSIPPI VALLEY. IT WILL DRIVE
A RAPIDLY STRENGTHENING SURFACE LOW FROM SW MISSOURI TO NORTHEAST
INDIANA. NUISANT SMALL PRECIP CHANCES WILL LINGER OVER N-C
WISCONSIN AND CENTRAL WISCONSIN IN THE MORNING BUT THE MAIN SHOW
WILL ARRIVE IN THE AFTERNOON AS THE SURFACE LOW MOVES OVER ILLINOIS
AND INDIANA. INCREASING UPPER DIVERGENCE IN THE LEFT FRONT QUAD OF A
JETSTREAK...AND STRONG FGEN CENTERED AROUND 700MB ON THE NW FLANK OF
THE SURFACE LOW WILL LEAD TO PRECIP SPREADING NORTHEAST OVER CENTRAL
AND NORTHEAST WISCONSIN MID-AFTERNOON ONWARD. NEGATIVE EPV ABOVE
THIS FGEN LAYER WILL SUPPORT ENHANCED BANDING ACTIVITY WHICH COULD
LEAD TO LOCALLY HEAVIER SNOWFALL RATES. SOME RAIN MAY MIX IN WITH
THE SNOW OVER THE FOX VALLEY AND LAKESHORE AREAS WHERE TEMPS WILL BE
IN THE MID 30S AS THE PRECIP ARRIVES. BUT ONCE THE HEAVIER PRECIP
RATES MOVE IN...A TIGHTENING BAROCLINIC ZONE WILL LIKELY LEAD TO
RAPIDLY ACCUMULATING SNOW FOR THE EVENING COMMUTE. COULD SEE A
QUICK 1-3 INCHES OF HEAVY SNOW FOR THE FOX VALLEY AND LAKESHORE BY
00Z SATURDAY WITH LESSER AMOUNTS TO THE NORTHWEST. WILL HOIST A
WINTER STORM WATCH STARTING AT 3 PM FOR WINNEBAGO TO SOUTHERN
MARINETTE ON EAST.
.LONG TERM...FRI NGT THRU NXT THU. FAIRLY PROGRESSIVE MEAN FLOW
ACROSS THE COUNTRY AS ONE LONGWAVE TROF MOVES ACROSS THE ERN CONUS
THIS WEEKEND...TO BE FOLLOWED BY ANOTHER LONGWAVE TROF PUSHING
INTO THE WRN CONUS EARLY NXT WEEK. NE WI TO DEAL WITH INITIAL TROF
INTO THE WEEKEND...HOWEVER UPR RIDGING BETWEEN THE TWO TROFS WL
BRING A GOOD WARM-UP EARLY TO MID-WEEK. THE APPROACH OF A CDFNT
WED/THU WL BRING THE NXT BEST CHC OF SEEING WIDESPREAD PCPN.
MDLS CONT TO CONVERGE ON A STORM TRACK FROM TAKING A DEEPENING SFC
LOW ROUGHLY FROM SW LWR MI NEWD TO EXTREME SE ONTARIO FRI NGT.
ACCUMULATING SNOW WL CONT TO IMPACT PRIMARILY ERN WI WHERE AN ADDL
2 TO 4 INCHES IS PSBL DURING THE EVENING. CONVERSELY...WRN SECTIONS
OF THE FCST AREA (GENERALLY WEST OF HWY 51) WL BE LUCKY TO SEE AN
ADDL INCH OF NEW SNOW. STRONG CYCLONIC FLOW COMBINED WITH A SFC
TROF DROPPING SOUTH INTO WI WL KEEP AT LEAST A CHC OF SNOW SHWRS
ACROSS THE FCST AREA THRU THE OVRNGT PERIOD.
THE WEAK SFC TROF SAGS SWD TOWARD SRN WI ON SAT WITH A WEAKENING
CYCLONIC FLOW HANGING ON OVER THE WRN GREAT LKS. FURTHERMORE...THE
LONGWAVE TROF WL BE MOVING INTO THE REGION WITH SEVERAL EMBEDDED
SHORTWAVES PUSHING THRU WI. FINALLY...MID-LVL LAPSE RATES GET
PRETTY STEEP ADDING INSTABILITY TO THE ATMOSPHERE. ADD ALL THIS UP
AND WE ARE LOOKING AT A DECENT CHC OF SNOW SHWRS THROUGHOUT ALL OF
NE WI. WOULD NOT BE SURPRISED TO SEE A FEW LOCALLY HEAVIER SNOW
BURSTS WITH PERHAPS A QUICK ONE-HALF INCH TO AN INCH OF ACCUMULATION.
MAX TEMPS TO BE COOLER THAN PREV DAYS WITH READINGS TOPPING OUT IN
THE LWR TO MID 30S.
SNOW SHWRS SHOULD BECOME MORE ISOLATED IN NATURE SAT NGT AS THE SFC
TROF PULLS AWAY AND THE LOSS OF DAYTIME HEATING MINIMIZES THE
INSTABILITY. SKIES TO REMAIN MOSTLY CLOUDY THRU THE NGT...HOWEVER
ENUF COOL AIR TO HAVE SETTLED OVER THE REGION TO ALLOW TEMPS TO
DROP INTO THE TEENS NORTH/CENTRAL...NEAR 20 EAST-CENTRAL. THE
LONGWAVE TROF TO STILL BE SITUATED OVER THE GREAT LKS THRU SUNDAY...
THEREBY PROVIDING A MEAN NW FLOW ACROSS WI. A PROMINENT SHORTWAVE
IS FCST TO DIVE SE FROM MN TO NRN IL WITH EVEN A SEMBLENCE OF A WEAK
SFC LOW MOVING SE THRU IA. EXPECT TO SEE SCT SNOW SHWRS OVER MUCH OF
NE WI ON SUNDAY WITH MAX TEMPS ONLY REACHING THE MID 20S NORTH/
AROUND 30 CENTRAL/E-CENTRAL.
ANY SNOW SHWR ACTIVITY SHOULD DIMINISH SUNDAY EVENING AS THE
SHORTWAVE DIVES TOWARD THE OHIO RIVER VALLEY AND INSTABILITY
WEAKENS UPON SUNSET. AS HI PRES BUILDS ACROSS THE MIDWEST LATER
SUNDAY NGT...SKIES WL ATTEMPT TO BECOME PARTLY CLOUDY OVER AT LEAST
CENTRAL WI BRINGING ANOTHER COLD NGT TO THE FCST AREA. THE HI PRES
DRIFTS ACROSS WI ON MON AND WL BE SITUATED JUST TO OUR EAST BY 00Z
TUE. WINDS BACKING S-SW WL START TO TAP WARMER AIR TO OUR WEST...
BUT COOLS START TO THE DAY WL ONLY BRING MAX TEMPS ON MON INTO THE
30-35 DEG RANGE. AS THE HI PRES HEADS TOWARD THE ERN CONUS ON TUE...
A STRONG AREA OF LOW PRES WL BE MOVING ACROSS S-CENTRAL CANADA. A
TIGHT PRES GRADIENT TO EXIST ACROSS THE GREAT LKS...BRINGING
BLUSTERY CONDITIONS TO NE WI. THESE GUSTY S-SW WINDS WL ALSO DRAW
VERY MILD AIR INTO WI WITH 8H TEMPS CLIMBING TO NEAR +6C. DEPENDING
ON THE DEPTH OF THE SNOW COVER...MAX TEMPS SHOULD EASILY RISE INTO
THE 40S WITH ANY SNOW-FREE AREAS SURPASSING THE 50 DEG MARK.
THE NXT LONGWAVE TROF TO BE IN THE PROCESS OF PUSHING ACROSS THE
ROCKIES TUE NGT BEFORE REACHING THE NRN/CNTRL PLAINS ON WED.
PRECEDING THIS UPR TROF WL BE A CDFNT WHICH THE MDLS HAVE SOME
TIMING ISSUES WITH. LATEST TRENDS HAVE THIS FNT APPROACHING CENTRAL
WI BY WED AFTERNOON...THUS A NEED FOR CHC POPS ACROSS MOST OF NE
WI. ANOTHER MILD DAY WOULD HAVE ANY PCPN FALL AS RAIN WITH MAX
TEMPS TO RANGE FROM THE MID 40S NORTH TO AROUND 50 DEGS CENTRAL
AND EAST-CENTRAL WI. THE CDFNT DRIVES THRU MOST OF WI WED NGT WITH
A BAND OF LIGHT RAIN MIXING WITH AND CHANGING TO LIGHT SNOW AS
COOLER AIR ARRIVES BEHIND THE FNT. SOME DEBATE LINGERS AS TO
WHETHER THIS FNT WL BE ABLE TO CLEAR THE AREA BEFORE ANY SFC WAVES
CAN DEVELOP ON THE FNT TO SLOW ITS PROGRESS. HAVE USED A GENERAL
CONSENSUS FOR THU WHICH KEEPS THINGS DRY FOR NOW...BUT THU MAY
NEED TO BE RE-EVALUATED LATER AS THE 12Z ECMWF NOW DIGS AN UPR
TROF INTO THE CNTRL CONUS AND REVS UP A SFC LOW TOWARD CHICAGO.
&&
.AVIATION...LOOK FOR MVFR CIGS AND VSBYS DUE TO SNOW AND DRIZZLE TO
SLOWLY SPREAD FROM WEST TO EAST OVERNIGHT. IFR CIGS AND VSBYS WILL
BE PATCHY EARLY FRIDAY BEFORE BECOMING MORE WIDESPREAD FRIDAY
AFTERNOON AND EVENING.
TDH
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WATCH FROM FRIDAY AFTERNOON THROUGH LATE FRIDAY
NIGHT FOR WIZ022-038>040-048>050-073-074.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1131 PM CST THU MAR 1 2012
.SHORT TERM...TONIGHT THROUGH SUNDAY
347 PM CST THU MAR 1 2012
AT 3 PM...THE WATER VAPOR IMAGERY AND PROFILER NETWORKS SHOW THAT
A SHORT WAVE TROUGH WAS MOVING ACROSS SOUTHWEST MINNESOTA AND
WESTERN IOWA. THE RUC SOUNDINGS CONTINUE TO SHOW THAT MUCH OF THE
SYNOPTIC AND ISENTROPIC LIFT ASSOCIATED WITH THIS WAVE GOES TO
SATURATION. THIS IS LIKELY THE REASON WHY THE RADARS ARE
INDICATING SOME ECHOS ACROSS SOUTH CENTRAL MINNESOTA AND NORTHEAST
IOWA. HOWEVER WITH THE AIR MASS DRY IN THE LOW LEVELS...NOT SEEING
ANYTHING REACHING THE GROUND. THIS WAVE WILL MOVE THROUGH SOUTHERN
WISCONSIN THIS EVENING...SO JUST LEFT A 20 PERCENT CHANCE OF
PRECIPITATION TO COVER THIS SYSTEM. FURTHER TO THE NORTHWEST...
ANOTHER SHORT WAVE TROUGH WAS MOVING THROUGH EASTERN NORTH DAKOTA.
THIS SYSTEM LOOKS TO BE TOO FAR NORTH AND WEST TO PRODUCE ANY
PRECIPITATION ACROSS EITHER SOUTHEAST MINNESOTA OR NORTH-CENTRAL
WISCONSIN. AS A RESULT...LOWERED THE PRECIPITATION CHANCES FOR
TONIGHT IN THESE AREAS. MEANWHILE BETWEEN THESE TWO SYSTEM WILL
LIKELY NOT SEE ANY PRECIPITATION...SO TOOK OUT THE PRECIPITATION
CHANCES OUT FOR THESE AREAS.
ON FRIDAY...THE 01.12Z MODELS ARE MUCH CLOSER TO COMING UP WITH A
CONSENSUS FORECAST. THE NAM/WRF HAS KEPT ITS IDEA THAT THERE WOULD
BE SOME PHASING BETWEEN THE NORTHERN AND SOUTHERN STREAMS...THUS...
IT HAS KEPT A STRONGER LOW PRESSURE SYSTEM. WHILE THIS HAS BEEN
CONSISTENT...IT HAS SHIFT THE SURFACE LOW MUCH FURTHER SOUTHEAST
WITH IT TRACKING FROM NORTHERN MISSOURI INTO SOUTHWEST LOWER
MICHIGAN. THIS TRACK IS MORE IN LINE WITH WHAT THE GFS...GEM...
ECMWF...AND UKMET HAVE BEEN SHOWING FOR THE PAST SEVERAL DAYS.
MEANWHILE THE GFS...GEM...ECMWF...AND UKMET ARE NOW SHOWING SOME
PHASING BETWEEN THE NORTHERN AND SOUTHERN STREAMS...SO THEY HAVE A
SIMILAR STRENGTH LOW TO THE NAM/WRF. WHILE THEY MADE THIS
CHANGE...THERE SURFACE LOW TRACK HAS REMAINED RATHER CONSISTENT.
ALL OF THE MODELS ARE SUGGESTING THAT THERE WILL BE STRONG 900 TO
700 MB FRONTOGENESIS ACROSS FAR EASTERN IOWA...NORTHWEST
ILLINOIS...AND SOUTHERN WISCONSIN. ABOVE THIS FRONTOGENESIS...
THERE IS SOME NEGATIVE EPV. AS A RESULT...EXPECTING TO SEE SOME
SLANTWISE CONVECTION TO DEVELOP. THIS INTERSECTS THE -15C OMEGA...SO
THERE WILL BE POSSIBILITY OF 1 TO 2 INCH AN HOUR SNOW RATES. THE
01.15Z SREF DOES SUGGEST THAT THERE WILL BE SOME PROBABILITIES FOR
THIS JUST TO THE EAST OF OUR FORECAST AREA. WITH ALL OF THIS IN
MIND...THINKING THAT THERE WILL BE A BAND OF 2 TO 4 INCHES OF SNOW
EAST OF A DUBUQUE IOWA TO WAUTOMA WISCONSIN LINE. IF THESE SNOW
TOTALS STILL LOOK REALISTIC TONIGHT...WE MAY HAVE TO ISSUE A
WINTER WEATHER ADVISORY FOR THIS AREA. ONE CONCERN ABOUT DOING
THIS IS THAT THE TEMPERATURES ARE ABOVE FREEZING AND THEY MAY HAVE
A HARD TIME ACCUMULATING IF THE RATES ARE NOT HIGH ENOUGH.
FROM FRIDAY NIGHT INTO SUNDAY...IT CONTINUES TO LOOK LIKE A LONG
WAVE TROUGH WILL BE LOCATED ACROSS THE REGION. EMBEDDED WEAK SHORT
WAVE TROUGHS IN THIS MAIN WAVE MAY PRODUCE PERIODIC CHANCES FOR
LIGHT SNOW. OVERALL...IF THE SNOW DOES OCCUR...NOT EXPECTING TOO
MUCH ACCUMULATIONS FROM THESE SYSTEMS.
.LONG TERM...SUNDAY NIGHT THROUGH THURSDAY
347 PM CST THU MAR 1 2012
ON TUESDAY...THE MODELS ARE CONTINUING TO INDICATE THAT A 500 MB
HIGH WILL DEVELOP ACROSS THE SOUTHEAST UNITED STATES. SOUTHERLY
WINDS ON THE BACKSIDE OF THIS HIGH WILL BRING WELL ABOVE NORMAL
TEMPERATURES INTO THE FORECASTS AREA. WE MAY SEE TWO TO THREE DAYS
WITH HIGH TEMPERATURES IN THE 50S. THERE MAY BE EVEN A FEW AREAS
THAT SEE TEMPERATURES IN THE 60S. SINCE THE ALL BLEND STILL HAS
SOME COLD SOLUTIONS IN IT...TRENDED THE TEMPERATURES FROM TUESDAY
NIGHT INTO WEDNESDAY TOWARD THE CONSALL INSTEAD OF THE ALL BLEND.
&&
.AVIATION...THROUGH 06Z SATURDAY
1131 PM CST THU MAR 1 2012
A LOW PRESSURE TROUGH WAS SITUATED ALONG NEAR I-35 AS OF LATE
THURSDAY EVENING. VFR CONDITIONS EXISTS AHEAD OF THE TROUGH OVER
THE TAF SITES...BUT JUST TO THE WEST OVER SOUTH CENTRAL
MINNESOTA...MVFR TO IFR CEILINGS WERE PRESENT. THESE LOWER
CEILINGS ARE LIKELY TO MAKE THEIR WAY EASTWARD INTO THE TAF SITES
IN THE 06-12Z PERIOD. CONFIDENCE IS LOW THAT THE IFR CONDITIONS
WOULD HIT EITHER TAF SITES...THOUGH...SINCE THE IFR CEILINGS ARE
PRESENT OVER AREAS THAT GOT SOME SNOW ACCUMULATION. CERTAINLY
THE POTENTIAL FOR IFR CEILINGS WILL NEED TO BE MONITORED THROUGH
THE EARLY MORNING HOURS. DRIER AIR SEEN IN SOUTHWEST MINNESOTA
IS EXPECTED TO MAKE INTO THE TAF SITES LATER TODAY...REACHING KRST
AT 18Z AND KLSE AT 00Z. THIS DRIER AIR WILL ALLOW CEILINGS TO
CLIMB TO VFR. THE REASON FOR THE DELAY AT KLSE IS A LOW PRESSURE
SYSTEM HEADING NORTHEAST THROUGH ILLINOIS. ANY PRECIPITATION FROM
THIS SYSTEM WILL STAY SOUTHEAST OF KLSE. WINDS ARE GOING TO
INCREASE AS THIS SYSTEM APPROACHES...THOUGH...AND IN FACT COULD
GET GUSTY AT KRST AFTER 03Z WHERE WEST-NORTHWEST GUSTS OF UP TO 22
KT ARE FORECAST. ACCOMPANYING THESE GUSTY WINDS SHOULD BE ANOTHER
SURGE OF LOW STRATUS WITH MVFR CEILINGS CURRENTLY IN NORTH DAKOTA.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
347 PM CST THU MAR 1 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
603 AM EST FRI MAR 2 2012
.SYNOPSIS...
ISSUED AT 536 AM EST FRI MAR 2 2012
WV IMAGERY AND RUC ANALYSIS INDICATED A TROUGH OVER THE WRN CONUS. A
MID/UPPER LEVEL LOW WAS LOCATED OVER ND WHILE SEVERAL PROMINENT
SHORTWAVES WERE EMBEDDED IN THE FLOW FROM UT/CO INTO THE CNTRL
PLAINS. AT THE SFC...A 1002 MB LOW WAS LOCATED OVER THE NW CORNER OF
WHILE A STRONGER AND DEEPENING 995 MB LOW WAS MOVING FROM OK INTO SW
MO. LIGHT WINDS PREVAILED OVER THE WRN GREAT LAKES AHEAD OF A WEAK
TROUGH OVER THE UPPER MS VALLEY. A WEAK SHRTWV FROM NE MN INTO NW WI
SUPPORTED NO MORE THAN PATCHY LIGHT SNOW OR FLURRIES. WITH ABUNDANT
LOW LEVEL MOISTURE OVER THE AREA...PATCHY FOG HAD ALSO
DEVELOPED OVER PORTIONS OF THE N CNTRL AND WRN CWA.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 536 AM EST FRI MAR 2 2012
TODAY...
SOME PATCHY LIGHT SNOW MAY BE POSSIBLE THIS MORNING INTO
EARLY AFTERNOON BUT IS NOT EXPECTED TO BE MEASURABLE. EVEN WITH
TEMPS LINGERING AROUND 30...CLOUDS WILL REMAIN THICK ENOUGH TO KEEP
MAX READINGS THIS AFTERNOON IN THE MID 30S. SOME LIGHT SNOW MAY
EXPAND INTO THE AREA LATE FROM S TO NORTH BUT ACCUMULATIONS DURING
BY 00Z SHOULD REMAIN GENERALLY LESS THAN A HALF INCH.
TONIGHT INTO SATURDAY...
MDLS HAVE COME INTO REASONABLY GOOD
AGREEMENT WITH THE DEVELOPING STORM SYSTEM AS THE SE COLORADO SHRTWV
LIFTS TO THE NORTHEAST AND PHASES WITH THE ND LOW. THE SW MO SFC LOW
IS EXPECTED TO DEEPEN RAPIDLY AS IT MOVES TO NW INDIANA THIS
AFTERNOON AND LAKE HURON TONIGHT. THE STRONGEST MID LEVEL FGEN
FORCING WITH THE STRENGTHENING DEFORMATION ZONE IS EXPECTED TO MOVE
THROUGH NW LOWER MI. EVEN THROUGH THE STRONGER DYNAMICS ARE EXPECTED
TO REMAIN TO THE SE OF THE CWA...THE AREA 290K-295K ISENTROPIC LIFT
AND STRONG MOISTURE TRANSPORT IS EXPECTED TO BRING AND EXPANDING
BAND OF PCPN INTO UPPER MICHIGAN. THE MODELS HAVE ALSO TRENDED
TOWARD A SLIGHTLY LATER ARRIVAL OF THE HEAVIER PCPN...AFT 00Z INTO
THE S CNTRL AND AFT 03Z INTO THE NRN HALF OF THE CWA. IN ADDITION
DOWNSLOPE NE FLOW FROM ONTARIO MAY FURTHER DELAY THE PCPN TOWARD
NEWBERRY.
WITH THE STRONGEST UPWARD MOTION MAINLY ABOVE THE DGZ...SNOW/WATER
RATIOS SHOULD REMAIN RELATIVELY LOW...GENERALLY IN THE 10/1 TO 15/1
RANGE. MODELS CONSENSUS QPF VALUES AN SUGGEST SNOWFALL AMOUNTS WILL
APPROACH WARNING CRITERIA (6 INCHES/12 HOURS) FROM SE DELTA INTO
LUCE COUNTY. STRONGER NE UPSLOPE FLOW BACKING NRLY INTO N CNTRL
UPPER MI WITH 850 MB TEMPS FROM -8C DROPPING TO NEAR -12C TO -14C BY
MIDDAY SATURDAY SHOULD BRING SUBSTANTIAL LAKE/TERRAIN ENHANCEMENT.
HOWEVER...KEPT THE WINTER STORM WATCH GOING SINCE CONFIDENCE IN
REACHING WARNING AMOUNTS REMAINS LIMITED GIVEN REMAINING DIFFERENCES
IN THE STRENGTH OF THE SYSTEM AND RESULTING QPF FIELDS
(ECMWF/GEM/UKMET WERE WEAKER THAN THE GFS/NAM). ADVISORIES MAY ALSO
BE NEEDED OVER THE WEST BY TONIGHT AS LAKE EFFECT/ENHANCED SNOW
AMOUNTS NEAR IWD/CMX INTO THE 2 TO 4 INCH RANGE ARE POSSIBLE.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 536 AM EST FRI MAR 2 2012
NNW WINDS AT 850MB TO NNE WINDS NEAR THE SFC WILL ALLOW FOR SOME
BREAKDOWN IN THE PERFECT LES STRUCTURE...BUT 850MB TEMPS OF -14 TO
-18C /COOLEST OFF THE 02/00Z GFS/ SHOULD KEEP THE BEST CHANCE OF
SNOW SHOWERS GOING FROM ONTONAGON EASTWARD NEAR LAKE SUPERIOR.
EXPECT 1 TO 3 INCHES OF NEW SNOW NEAR LAKE SUPERIOR /HIGHEST NORTH
CENTRAL/ SATURDAY NIGHT...AS ANOTHER 500MB TROUGH DIPS IN FROM THE
NW. THE BEST DYNAMICS LOOK TO SLIDE ACROSS CENTRAL TO SOUTHERN WI.
BRIEF ENHANCEMENT WILL BE POSSIBLE DURING THE DAY SUNDAY...MAINLY IN
THE FORM OF ADDITIONAL CLOUD COVER AS ANOTHER SHORTWAVE NEARS FROM
THE WEST. SIMILAR TO SATURDAY NIGHT...MUCH OF THE ENERGY WILL FALL
OVER WI. NEW SNOW ON SUNDAY WILL LIKELY ADD UP TO ANOTHER INCH NEAR
LAKE SUPERIOR. LOOK FOR LES TO SLOWLY DIMINISH THROUGH SUNDAY
EVENING...AS SFC WINDS BECOME MORE WESTERLY PUSHING LES OFFSHORE.
THE SFC RIDGE SHOULD BE OVERHEAD DURING THE DAY SUNDAY HELPING TO
DRY US OUT.
THE FCST WARMUP FOR EARLY NEXT WEEK STILL LOOKS ON TRACK WITH THE
HIGH AMPLITUDE 500MB RIDGE SWINGING IN FROM THE WEST. EXPECT LOW TO
MID 40S TUESDAY AND WEDNESDAY /WITH HIGHER VALUES NOT OUT OF THE
QUESTION/. THE WARMEST READINGS WITH THE STRONG SSW WINDS SHOULD BE
SOUTH CENTRAL AND ACROSS THE FAVORED DOWNSLOPE AREAS NEAR LAKE
SUPERIOR. HIGH TEMPS ON WEDNESDAY ARE TRICKY WITH QUICK SW FLOW AS
THE 500MB RIDGE AXIS SHIFTS TO OUR EAST. TEMPS COULD BE SUPPRESSED
SLIGHTLY DUE TO ADDITIONAL CLOUD COVER AND THE CHANCE OF RAIN
SLIDING FROM CENTRAL MANITOBA TUESDAY TO JAMES BAY BY DAYBREAK
WEDNESDAY. TIMING ON THE COLD FRONT LOOKS TO BE CLOSER TO 12Z
WEDNESDAY OVER WESTERN AND CENTRAL UPPER MI...WHICH COULD RESULT IN
FALLING TEMPS DURING THE DAY. HAVE GONE MIDDLE OF THE ROAD FOR MUCH
OF THE EXTENDED PERIOD...TRYING TO ADD UNCERTAINTY TO THE WX TYPE
AND TIMING WEDNESDAY INTO WEDNESDAY NIGHT.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 557 AM EST FRI MAR 2 2012
A TRICKY AVIATION FCST IS IN STORE FOR THE SHORT TERM. EXPECT
IFR/LIFR CONDITIONS AT KCMX/KSAW THROUGH THE MORNING WITH LOW LEVEL
MSTR TRAPPED BLO SUBSIDENCE INVRN IN THE WAKE OF DISTURBANCE MOVING
NEWD INTO ONTARIO. EXPECT CONDITIONS TO IMPROVE TO VFR WITH SOME
DAYTIME HEATING...BUT IFR CONDITIONS WL REDEVELOP TONIGHT UNDER
INCREASING CYCLONIC FLOW ARND DEEP LOW PRES MOVING NEWD THRU LWR MI.
LIGHT TO MODERATE SNOW WILL INCREASE BY LATE EVENING AND PERSIST
OVERNIGHT WITH VSBY FREQUENTLY BLO 2SM.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 536 AM EST FRI MAR 2 2012
LOW PRESSURE OVER MISSOURI WILL DEEPEN OVER SOUTHERN LOWER MICHIGAN
BY LATE AFTERNOON...BEFORE CROSSING CENTRAL LAKE HURON DURING THE
LATE EVENING HOURS...AND PUSHING INTO QUEBEC SATURDAY. NNE GALES OF
35 TO 40KTS WILL BE LIKELY FROM LATE THIS EVENING...AND TURN MORE
NORTHERLY THROUGH THE DAY SATURDAY. EXPECT A WEAKENING TROUGH TO
LINGER ACROSS THE UPPER GREAT LAKES THROUGH SATURDAY NIGHT. A RIDGE
WILL THEN BUILD ACROSS LS SUNDAY THROUGH MONDAY...BEFORE SHIFTING TO
THE LOWER GREAT LAKES MONDAY NIGHT. ANOTHER STRONG LOW...OVER
CENTRAL MANITOBA TUESDAY MORNING...WILL DRIFT TO CENTRAL ONTARIO
THROUGH THE DAY. ANOTHER PERIOD OF STRONGER WINDS...MAYBE UP TO
GALES AS THE TIME NEARS...WILL BE POSSIBLE TOWARD THE MIDDLE OF THE
WORK WEEK.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER STORM WATCH FROM THIS EVENING THROUGH SATURDAY AFTERNOON
FOR MIZ013-014-085.
WINTER STORM WATCH FROM THIS EVENING THROUGH SATURDAY EVENING
FOR MIZ005>007.
LAKE SUPERIOR...
GALE WARNING FROM 1 AM TO 7 PM EST SATURDAY FOR LSZ264>267.
GALE WARNING FROM 4 AM TO 1 PM EST SATURDAY FOR LSZ263.
GALE WARNING FROM 4 AM TO 7 PM EST SATURDAY FOR LSZ244-245-
248>251.
LAKE MICHIGAN...
NONE.
&&
$$
SYNOPSIS...JLB
SHORT TERM...JLB
LONG TERM...KF
AVIATION...JLB
MARINE...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
537 AM EST FRI MAR 2 2012
.SYNOPSIS...
ISSUED AT 536 AM EST FRI MAR 2 2012
WV IMAGERY AND RUC ANALYSIS INDICATED A TROUGH OVER THE WRN CONUS. A
MID/UPPER LEVEL LOW WAS LOCATED OVER ND WHILE SEVERAL PROMINENT
SHORTWAVES WERE EMBEDDED IN THE FLOW FROM UT/CO INTO THE CNTRL
PLAINS. AT THE SFC...A 1002 MB LOW WAS LOCATED OVER THE NW CORNER OF
WHILE A STRONGER AND DEEPENING 995 MB LOW WAS MOVING FROM OK INTO SW
MO. LIGHT WINDS PREVAILED OVER THE WRN GREAT LAKES AHEAD OF A WEAK
TROUGH OVER THE UPPER MS VALLEY. A WEAK SHRTWV FROM NE MN INTO NW WI
SUPPORTED NO MORE THAN PATCHY LIGHT SNOW OR FLURRIES. WITH ABUNDANT
LOW LEVEL MOISTURE OVER THE AREA...PATCHY FOG HAD ALSO
DEVELOPED OVER PORTIONS OF THE N CNTRL AND WRN CWA.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 536 AM EST FRI MAR 2 2012
TODAY...
SOME PATCHY LIGHT SNOW MAY BE POSSIBLE THIS MORNING INTO
EARLY AFTERNOON BUT IS NOT EXPECTED TO BE MEASURABLE. EVEN WITH
TEMPS LINGERING AROUND 30...CLOUDS WILL REMAIN THICK ENOUGH TO KEEP
MAX READINGS THIS AFTERNOON IN THE MID 30S. SOME LIGHT SNOW MAY
EXPAND INTO THE AREA LATE FROM S TO NORTH BUT ACCUMULATIONS DURING
BY 00Z SHOULD REMAIN GENERALLY LESS THAN A HALF INCH.
TONIGHT INTO SATURDAY...
MDLS HAVE COME INTO REASONABLY GOOD
AGREEMENT WITH THE DEVELOPING STORM SYSTEM AS THE SE COLORADO SHRTWV
LIFTS TO THE NORTHEAST AND PHASES WITH THE ND LOW. THE SW MO SFC LOW
IS EXPECTED TO DEEPEN RAPIDLY AS IT MOVES TO NW INDIANA THIS
AFTERNOON AND LAKE HURON TONIGHT. THE STRONGEST MID LEVEL FGEN
FORCING WITH THE STRENGTHENING DEFORMATION ZONE IS EXPECTED TO MOVE
THROUGH NW LOWER MI. EVEN THROUGH THE STRONGER DYNAMICS ARE EXPECTED
TO REMAIN TO THE SE OF THE CWA...THE AREA 290K-295K ISENTROPIC LIFT
AND STRONG MOISTURE TRANSPORT IS EXPECTED TO BRING AND EXPANDING
BAND OF PCPN INTO UPPER MICHIGAN. THE MODELS HAVE ALSO TRENDED
TOWARD A SLIGHTLY LATER ARRIVAL OF THE HEAVIER PCPN...AFT 00Z INTO
THE S CNTRL AND AFT 03Z INTO THE NRN HALF OF THE CWA. IN ADDITION
DOWNSLOPE NE FLOW FROM ONTARIO MAY FURTHER DELAY THE PCPN TOWARD
NEWBERRY.
WITH THE STRONGEST UPWARD MOTION MAINLY ABOVE THE DGZ...SNOW/WATER
RATIOS SHOULD REMAIN RELATIVELY LOW...GENERALLY IN THE 10/1 TO 15/1
RANGE. MODELS CONSENSUS QPF VALUES AN SUGGEST SNOWFALL AMOUNTS WILL
APPROACH WARNING CRITERIA (6 INCHES/12 HOURS) FROM SE DELTA INTO
LUCE COUNTY. STRONGER NE UPSLOPE FLOW BACKING NRLY INTO N CNTRL
UPPER MI WITH 850 MB TEMPS FROM -8C DROPPING TO NEAR -12C TO -14C BY
MIDDAY SATURDAY SHOULD BRING SUBSTANTIAL LAKE/TERRAIN ENHANCEMENT.
HOWEVER...KEPT THE WINTER STORM WATCH GOING SINCE CONFIDENCE IN
REACHING WARNING AMOUNTS REMAINS LIMITED GIVEN REMAINING DIFFERENCES
IN THE STRENGTH OF THE SYSTEM AND RESULTING QPF FIELDS
(ECMWF/GEM/UKMET WERE WEAKER THAN THE GFS/NAM). ADVISORIES MAY ALSO
BE NEEDED OVER THE WEST BY TONIGHT AS LAKE EFFECT/ENHANCED SNOW
AMOUNTS NEAR IWD/CMX INTO THE 2 TO 4 INCH RANGE ARE POSSIBLE.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 536 AM EST FRI MAR 2 2012
NNW WINDS AT 850MB TO NNE WINDS NEAR THE SFC WILL ALLOW FOR SOME
BREAKDOWN IN THE PERFECT LES STRUCTURE...BUT 850MB TEMPS OF -14 TO
-18C /COOLEST OFF THE 02/00Z GFS/ SHOULD KEEP THE BEST CHANCE OF
SNOW SHOWERS GOING FROM ONTONAGON EASTWARD NEAR LAKE SUPERIOR.
EXPECT 1 TO 3 INCHES OF NEW SNOW NEAR LAKE SUPERIOR /HIGHEST NORTH
CENTRAL/ SATURDAY NIGHT...AS ANOTHER 500MB TROUGH DIPS IN FROM THE
NW. THE BEST DYNAMICS LOOK TO SLIDE ACROSS CENTRAL TO SOUTHERN WI.
BRIEF ENHANCEMENT WILL BE POSSIBLE DURING THE DAY SUNDAY...MAINLY IN
THE FORM OF ADDITIONAL CLOUD COVER AS ANOTHER SHORTWAVE NEARS FROM
THE WEST. SIMILAR TO SATURDAY NIGHT...MUCH OF THE ENERGY WILL FALL
OVER WI. NEW SNOW ON SUNDAY WILL LIKELY ADD UP TO ANOTHER INCH NEAR
LAKE SUPERIOR. LOOK FOR LES TO SLOWLY DIMINISH THROUGH SUNDAY
EVENING...AS SFC WINDS BECOME MORE WESTERLY PUSHING LES OFFSHORE.
THE SFC RIDGE SHOULD BE OVERHEAD DURING THE DAY SUNDAY HELPING TO
DRY US OUT.
THE FCST WARMUP FOR EARLY NEXT WEEK STILL LOOKS ON TRACK WITH THE
HIGH AMPLITUDE 500MB RIDGE SWINGING IN FROM THE WEST. EXPECT LOW TO
MID 40S TUESDAY AND WEDNESDAY /WITH HIGHER VALUES NOT OUT OF THE
QUESTION/. THE WARMEST READINGS WITH THE STRONG SSW WINDS SHOULD BE
SOUTH CENTRAL AND ACROSS THE FAVORED DOWNSLOPE AREAS NEAR LAKE
SUPERIOR. HIGH TEMPS ON WEDNESDAY ARE TRICKY WITH QUICK SW FLOW AS
THE 500MB RIDGE AXIS SHIFTS TO OUR EAST. TEMPS COULD BE SUPPRESSED
SLIGHTLY DUE TO ADDITIONAL CLOUD COVER AND THE CHANCE OF RAIN
SLIDING FROM CENTRAL MANITOBA TUESDAY TO JAMES BAY BY DAYBREAK
WEDNESDAY. TIMING ON THE COLD FRONT LOOKS TO BE CLOSER TO 12Z
WEDNESDAY OVER WESTERN AND CENTRAL UPPER MI...WHICH COULD RESULT IN
FALLING TEMPS DURING THE DAY. HAVE GONE MIDDLE OF THE ROAD FOR MUCH
OF THE EXTENDED PERIOD...TRYING TO ADD UNCERTAINTY TO THE WX TYPE
AND TIMING WEDNESDAY INTO WEDNESDAY NIGHT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1205 AM EST FRI MAR 2 2012
A TRICKY AVIATION FCST IS IN STORE FOR THE SHORT TERM. EXPECT
IFR/LIFR CONDITIONS AT ALL 3 SITES THRU THE MRNG WITH LLVL MSTR
TRAPPED BLO SUBSIDENCE INVRN IN THE WAKE OF DISTURBANCE MOVING NEWD
INTO ONTARIO. IWD WL LIKELY SEE THE WORST CONDITIONS EARLY IN THE
PERIOD WITH SOME CLRG/RADIATION FOG BEFORE THE ARRIVAL OF THICKER
CLDS AGAIN TOWARD 09Z CAUSES THIS FOG TO BREAK UP A BIT. EXPECT
CONDITIONS TO IMPROVE TO VFR WITH SOME DAYTIME HEATING...BUT IFR
CONDITIONS WL REDEVELOP TNGT UNDER INCRSG CYC FLOW ARND DEEP LO PRES
MOVING NEWD THRU LWR MI.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 536 AM EST FRI MAR 2 2012
LOW PRESSURE OVER MISSOURI WILL DEEPEN OVER SOUTHERN LOWER MICHIGAN
BY LATE AFTERNOON...BEFORE CROSSING CENTRAL LAKE HURON DURING THE
LATE EVENING HOURS...AND PUSHING INTO QUEBEC SATURDAY. NNE GALES OF
35 TO 40KTS WILL BE LIKELY FROM LATE THIS EVENING...AND TURN MORE
NORTHERLY THROUGH THE DAY SATURDAY. EXPECT A WEAKENING TROUGH TO
LINGER ACROSS THE UPPER GREAT LAKES THROUGH SATURDAY NIGHT. A RIDGE
WILL THEN BUILD ACROSS LS SUNDAY THROUGH MONDAY...BEFORE SHIFTING TO
THE LOWER GREAT LAKES MONDAY NIGHT. ANOTHER STRONG LOW...OVER
CENTRAL MANITOBA TUESDAY MORNING...WILL DRIFT TO CENTRAL ONTARIO
THROUGH THE DAY. ANOTHER PERIOD OF STRONGER WINDS...MAYBE UP TO
GALES AS THE TIME NEARS...WILL BE POSSIBLE TOWARD THE MIDDLE OF THE
WORK WEEK.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER STORM WATCH FROM THIS EVENING THROUGH SATURDAY AFTERNOON
FOR MIZ013-014-085.
WINTER STORM WATCH FROM THIS EVENING THROUGH SATURDAY EVENING
FOR MIZ005>007.
LAKE SUPERIOR...
GALE WARNING FROM 1 AM TO 7 PM EST SATURDAY FOR LSZ264>267.
GALE WARNING FROM 4 AM TO 1 PM EST SATURDAY FOR LSZ263.
GALE WARNING FROM 4 AM TO 7 PM EST SATURDAY FOR LSZ244-245-
248>251.
LAKE MICHIGAN...
NONE.
&&
$$
SYNOPSIS...JLB
SHORT TERM...JLB
LONG TERM...KF
AVIATION...KC
MARINE...KF
AREA FORECAST DISCUSSION
NWS SPRINGFIELD MO
623 AM CST FRI MAR 2 2012
...MESOSCALE CONVECTIVE DISCUSSION...
.UPDATE...
/ISSUED 615 AM CST FRI MAR 2 2012/
SURFACE LOW WAS TRACKING NORTHEAST ACROSS SOUTHERN MISSOURI EARLY
THIS MORNING AND WAS LOCATED NEAR SPRINGFIELD AT 12Z (7 AM).
SCATTERED CONVECTION CONTINUED ALONG AND JUST BEHIND THE ASSOCIATED
FRONT. SEVERE STORMS THAT PRODUCED LARGE HAIL ACROSS PORTIONS OF
CENTRAL MISSOURI EARLIER THIS MORNING HAD TRACKED EAST OF THE
AREA ON THE NOSE OF THE LOW LEVEL JET.
MOST UNSTABLE CAPES AROUND 1000 J/KG AND OVER 70 KTS OF DEEP
LAYERED SHEAR WILL SUPPORT THE POTENTIAL FOR ADDITIONAL SEVERE
STORMS AHEAD OF THE FRONT THIS MORNING. STORMS EARLY ON WILL
CONTINUE TO BE PRIMARILY ELEVATED IN NATURE BUT THERE IS CONCERN
THAT STORMS WILL BECOME ROOTED NEAR OR AT THE SURFACE ACROSS SOUTH
CENTRAL MISSOURI AS THE MORNING PROGRESSES. LATEST RUC ANALYSIS
DEPICTS DECREASING MIXED LAYER INHIBITION ACROSS FAR SOUTH CENTRAL
MISSOURI. THIS TREND WILL LIKELY CONTINUE AS RICHER LOW LEVEL
MOISTURE STREAMS NORTH. IF STORMS BECOME SURFACE BASED THE RISK
FOR DAMAGING WINDS AND ISOLATED TORNADOES WOULD INCREASE.
FOSTER
&&
.DISCUSSION...
/ISSUED 245 AM CST FRI MAR 2 2012/
THUNDERSTORMS WERE RAPIDLY DEVELOPING EARLY THIS MORNING ACROSS
PORTIONS OF SOUTHWEST AND CENTRAL MISSOURI NORTHEAST OF A SURFACE
LOW PRESSURE SYSTEM LOCATED IN NORTHEAST OKLAHOMA. STRONG WARM AIR
AND MOISTURE ADVECTION EAST OF THIS LOW OVER TOP THE BOUNDARY
LAYER WAS RESULTING RAPID DESTABILIZATION. MOST UNSTABLE CAPE OF
AROUND 1000 TO NEAR 2000 J/KG WAS NOSING INTO SOUTHERN MISSOURI.
THIS INSTABILITY COUPLED WITH STRONG DEEP LAYERED SHEAR WILL
SUPPORT STRONG TO SEVERE CONVECTION EARLY THIS MORNING. CONVECTIVE
MODE WILL BE ELEVATED SUPERCELLS WITH LARGE HAIL THE PRIMARY RISK. THIS
ACTIVITY WILL RACE EASTWARD.
WILL HAVE TO CLOSELY MONITOR CONVECTIVE TRENDS FARTHER SOUTH ALONG
THE ARKANSAS BORDER CLOSER TO THE SURFACE WARM FRONT. CONVECTION
COULD BECOME ROOTED NEAR THE SURFACE IN THIS AREA RESULTING IN A
GREATER RISK FOR DAMAGING WINDS
EXPECT ACTIVITY TO MOVE EAST OF THE AREA BY EARLY AFTERNOON IF NOT
EARLIER. COLDER AIR ADVECTION WILL DEVELOP DURING THE AFTERNOON AS
THE SURFACE LOW MOVES OFF TO THE EAST RESULTING STEADY IF NOT
FALLING TEMPERATURES. A CHILLY NIGHT IS IN STORE TONIGHT WITH MANY
AREAS NEAR THE FREEZING MARK. BELOW NORMAL TEMPERATURES ARE IN
STORE FOR SATURDAY AS AN UPPER TROUGH SWINGS ACROSS THE REGION.
MODERATING TEMPERATURES WILL BEGIN SUNDAY WITH A MORE SUBSTANTIAL
WARMING TREND BEGINNING MONDAY AS A SOUTHERLY FLOW DEVELOPS. WILL
HAVE TO MONITOR FIRE WEATHER CONDITIONS MONDAY GIVEN GUSTY
SOUTHERLY WINDS AND EXISTING DRY AIR MASS.
PRECIPITATION CHANCES RETURN BY THE MIDDLE OF NEXT WEEK AS THE
NEXT UPPER TROUGH APPROACHES.
&&
.AVIATION...
/ISSUED 610 AM CST FRI MAR 2 2012/
A COLD FRONT WILL MOVE ACROSS THE AREA THIS MORNING BRINGING A
WIND SHIFT TO THE NORTHWEST AND A PERIOD OF MVFR CEILINGS.
SCATTERED SHOWERS AND THUNDERSTORMS WILL ALSO ACCOMPANY THE
FRONTAL PASSAGE. EXPECT IMPROVING FLIGHT CONDITIONS THIS AFTERNOON
BUT SURFACE WINDS WILL REMAIN GUSTY WITH FREQUENT GUSTS OVER 20
KTS. VFR CONDITIONS WILL PREVAIL TONIGHT INTO SATURDAY AS SURFACE
HIGH PRESSURE BUILDS INTO THE REGION.
FOSTER
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
631 AM EST FRI MAR 2 2012
.SYNOPSIS...
A STATIONARY FRONT OVER SOUTHEASTERN NORTH CAROLINA WILL LIFT NORTH
AS A WARM FRONT THIS MORNING. A STRONG COLD FRONT WILL BRING
THUNDERSTORMS SATURDAY AFTERNOON AND EVENING. COOLER AND DRIER HIGH
PRESSURE WILL BUILD INTO THE AREA EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM FRIDAY...INCOMING CONVECTIVE LINE IS QUITE A BIT
STRONGER THAN INITIALLY THOUGHT SEVERAL HOURS AGO. NEARLY DRY
ADIABATIC LAPSE RATE SHOWN ON THE LATEST RUC SOUNDINGS BETWEEN
700-500 MB IS FUELING INTENSE UPDRAFTS IN THE SC SQUALL LINE. SOME
OF THE CELLS SOUTH OF CHARLOTTE HAVE EXHIBITED DEVIANT MOTION...
CELL SPLITS...ANTICYCLONIC ROTATION...AND INTENSE HAIL CORES WITH
THREE-BODY SCATTER SPIKES. WOW! OLD VIL OF THE DAY CALCULATIONS FOR
3/4 INCH HAIL (BASED ON 400/500 MB TEMPS) IS 36 KG/M^2. OUR LOCAL
STUDY FOR SEVERE HAIL SHOWS 50 DBZ AT 29000 FT OR HIGHER WILL
PROBABLY PRODUCE ONE-INCH HAIL.
I`VE INCREASED POPS INTO THE 60-80 PERCENT RANGE ACROSS THE SC PEE
DEE REGION INTO LUMBERTON...AND ALSO INCREASED POPS IN THE CHANCE
RANGE ALL THE WAY DOWN TO THE COAST. NO OTHER SIGNIFICANT CHANGES.
PREVIOUS DISCUSSION FOLLOWS...
A NEARLY STATIONARY FRONT EXTENDING EAST-WEST FROM AROUND NEW BERN
TO NEAR KINSTON...TO FAYETTEVILLE...SOUTHERN PINES...WADESBORO AND
MONROE...WILL MOVE LITTLE THROUGH DAYBREAK. THE BOUNDARY WILL JUMP
NORTH LATER THIS MORNING WITH SOUTHERLY WINDS BRINGING SUBTROPICAL
MOISTURE ACROSS ALL OF NORTH AND SOUTH CAROLINA. A WEAK UPPER
DISTURBANCE WILL CROSS THE AREA LATE THIS MORNING JUST BEHIND THE
RETREATING FRONT BRINGING THE POTENTIAL FOR SCATTERED SHOWERS OR
THUNDERSTORMS TO MAINLY THE INLAND PORTIONS OF THE CAROLINAS. THE
DISTURBANCE WILL HELP COOL THE 700 MB TEMP JUST ENOUGH TO ERODE A
CONVECTIVE CAP ALLOWING SOME ELEVATED CONVECTION TO OCCUR. THE LAST
FEW RUNS OF THE HRRR HIGH-RESOLUTION MESOSCALE MODEL SHOW A
CONVECTIVE CHARACTER TO FORECAST PRECIPITATION ECHOES ACROSS THE
CENTRAL CAROLINAS IN THE 14-17Z TIME FRAME. PRECIPITATION CHANCES
WILL DROP TO LESS THAN 10 PERCENT BY MID-AFTERNOON AS THE
DISTURBANCES SWINGS BY TO THE NORTHEAST.
TONIGHT WARM AND MOIST SOUTH-SOUTHWESTERLY FLOW WILL CONTINUE OUT
AHEAD OF A STRONG COLD FRONT ADVANCING STEADILY EASTWARD. SHOWERS
AND THUNDERSTORMS ALONG THE FRONT WILL REACH THE PEE DEE REGION
LATE...PROBABLY AROUND 4 AM...AND MAY REACH THE COAST AROUND SUNRISE
SATURDAY MORNING. ALTHOUGH THIS IS THE SAME SYSTEM ANTICIPATED TO
BRING A LARGE SEVERE WEATHER OUTBREAK TO PORTIONS OF THE MID-SOUTH
AND TENNESSEE/OHIO VALLEYS TODAY...THE SYNOPTIC SITUATION IS NOT
QUITE AS FAVORABLE THIS FAR EAST SINCE THE PARENT UPPER DISTURBANCE
WILL BE SHEARING OUT TO THE NORTHEAST. THE LATE-NIGHT TIMING COUPLED
WITH COLD NEARSHORE OCEAN WATER TEMPERATURES ARE ALSO UNFAVORABLE
FACTORS FROM THE STANDPOINT OF MAINTAINING STRONG SURFACE-BASED
CONVECTION.
HIGHS TODAY SHOULD RANGE FROM THE MID 70S ACROSS MOST OF
SOUTHEASTERN NORTH CAROLINA...TO NEAR 80 ACROSS THE PEE DEE REGION
OF SOUTH CAROLINA. MUCH LIKE YESTERDAY WINDS BLOWING ONSHORE FROM
THE COLD NEARSHORE OCEAN WILL KEEP TEMPERATURES A GOOD 10-15 DEGREES
COLDER THAN INLAND AREAS. TONIGHT LOWS SHOULD ONLY FALL INTO THE
LOWER 60S WITH A STEADY SOUTH-SOUTHWEST WIND CONTINUING.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 330 AM FRIDAY...LATEST FORECAST SOUNDINGS SUGGEST THIS
WEEKENDS RAIN EVENT COULD BRING SIGNIFICANT RAINFALL TO THE
REGION. YESTERDAY SOUNDINGS WERE SHOWING A BRIEF PERIOD THE
ATMOSPHERE WAS NEARLY SATURATED. HOWEVER THE LATEST GUIDANCE IS
MUCH WETTER. IT NOW LOOKS LIKE THE FRONT WILL DROP INTO THE AREA
SAT MORNING THEN STALL AS THE FRONT ENDS UP LAYING PARALLEL TO THE
FLOW ALOFT. EARLIER SOLUTIONS HAD THE FRONT STALLING OFF THE
COAST...A SOLUTION WHICH STILL COULD COME TO PASS. SPC HAS PUT
MOST OF THE FORECAST AREA INTO THE DAY 2 SLIGHT RISK...BUT THREAT
APPEARS LIMITED. FIRST THERE WILL BE CONSIDERABLE CLOUD COVER
ACROSS THE AREA SAT...LIMITING DIURNAL HEATING. MID LEVEL LAPSE
RATES ARE MARGINAL AT BEST MOSTLY UNDER 6C/KM. LOW LEVEL JETTING
IN FORECAST SOUNDINGS IS WEAKER THAN IN PREVIOUS RUNS. STRONG
SOUTHWEST FLOW WILL PUSH TEMPERATURES INTO THE LOW 70S DESPITE
CLOUDS AND PRECIP.
SURFACE WAVE DEVELOPS ALONG THE FRONT LATE SAT INTO SAT NIGHT SOUTH
OF THE AREA THEN TRACKS NORTHEAST ALONG THE FRONT BRINGING ANOTHER
ROUND OF SHOWERS AND ISOLATED THUNDERSTORMS TO THE REGION SAT NIGHT
INTO SUN. 5H TROUGH MOVES INTO THE AREA EARLY SUN...PUSHING THE
FRONT...ALONG WITH ANY ASSOCIATED PRECIP...OFF THE COAST. ARRIVAL
TIME OF COLD AIR SAT NIGHT WILL BE KEY TO DETERMINING HOW LOW TEMPS
DROP. SOME LIGHT PRECIP MAY LINGER INTO SUN MORNING BUT OVERALL SUN
SHOULD BE DRY WITH SKIES CLEARING DURING THE DAY. COLD ADVECTION
WILL KEEP TEMPS BELOW CLIMO SUN AND SUN NIGHT. HOWEVER BOUNDARY
LAYER REMAINS WELL MIXED SUN NIGHT...PREVENT TEMPS FROM DROPPING
BELOW FREEZING.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 330 AM FRIDAY...5H TROUGH WILL BE IN THE PROCESS OF LIFTING
NORTHEAST AT THE START OF THE PERIOD. DRY COLD FRONT MOVES ACROSS
THE REGION EARLY MON BUT ALL IT WILL BRING IS A REINFORCING SHOT
OF COOLER AIR LATER IN THE DAY. INCREASE IN CLOUD COVER MON
ASSOCIATED THIN LAYER OF MOISTURE BETWEEN 850 AND 750 MB IN
CONJUNCTION WITH A SHORTWAVE ROTATING AROUND THE BASE OF THE UPPER
TROUGH. PRECIP IS NOT AN ISSUE AS MOISTURE IS NOT NEARLY DEEP
ENOUGH. REMAINDER OF THE PERIOD WILL REMAIN DRY WITH VERY LITTLE
IN THE WAY OF CLOUDS. TEMPERATURES BOTTOM OUT MON NIGHT INTO
TUE...WITH LOWS MON NIGHT AT OR BELOW FREEZING AND HIGHS TUE IN
THE MID 50S. ELONGATED RIDGE AXIS SHIFTS OFFSHORE TUE NIGHT WITH
LIGHT ONSHORE FLOW DEVELOPING. ECMWF/GFS BOTH SHOW WEAK COASTAL
TROUGH DEVELOPING TUE NIGHT BUT BOTH MOVE THIS FEATURE ONSHORE
WED. AT THIS POINT TROUGH LOOKS TOO WEAK TO SUPPORT PRECIP. 5H
RIDGE BUILDS OVER THE SOUTHEAST WED THEN STRENGTHENS FOR THU.
TEMPERATURES RETURN CLOSE TO CLIMO WED/WED NIGHT...RUNNING NEAR TO
SLIGHTLY ABOVE CLIMO THU/THU NIGHT.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
AS OF 12Z...A FRONTAL BOUNDARY LOCATED FROM NEAR LBT TO NORTH OF ILM
WILL LIFT BACK TO THE NORTH TODAY. HIGHLY VARIABLE FLIGHT CONDITIONS
EXPECTED THROUGH 14-15Z THIS MORNING WITH RAPID CHANGES FROM LIFR TO
MVFR/VFR DUE TO FOG AND SHOWERS/THUNDERSTORMS. CONFIDENCE IS
MODERATE TO HIGH FLIGHT CONDITIONS WILL IMPROVE TO MVFR OR HIGHER BY
AFTERNOON. THERE WILL BE A CHANCE OF SHOWERS AND THUNDERSTORMS THIS
MORNING...MOST LIKELY FLO/LBT WITH CONVECTION GRADUALLY WEAKENING AS
THE IT NEARS THE COASTAL TERMINALS. BY AFTERNOON EXPECT SHOWER
POTENTIAL TO WANE WITH VFR CONDITIONS HIGHLY LIKELY AS CLOUD COVER
DECREASES. AS THE PRESSURE GRADIENT TIGHTENS EXPECT SOUTH TO
SOUTHWEST WIND GUSTS TO 20-25 KNOTS TO DEVELOP.
BY LATE AFTERNOON AND EVENING EXPECT WIND GUSTS TO SUBSIDE BUT
SUSTAINED WINDS OF 10-15 KNOTS WILL PERSIST DURING THE EVENING AND
OVERNIGHT AS A COLD FRONT APPROACHES. VFR IS EXPECTED THIS
EVENING...EXCEPT AT CRE WHERE CONFIDENCE IS HIGH SEA FOG WILL LOWER
CEILINGS TO LIFR. AFTER 10Z MVFR CEILINGS WILL BECOME LIKELY AT
FLO/LBT AS SHOWERS AND THUNDERSTORMS APPROACH FROM THE WEST.
EXTENDED OUTLOOK...THUNDERSTORMS/TEMPO IFR SATURDAY INTO SUNDAY
MORNING. OTHERWISE VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM FRIDAY...NO SIGNIFICANT CHANGES WITH THIS EARLY MORNING
UPDATE. PREVIOUS DISCUSSION FOLLOWS...
A FRONT STALLED OUT ACROSS INLAND SOUTHERN NORTH CAROLINA WILL
RETREAT FARTHER NORTH TODAY...OPENING UP THE FLOODGATES FOR
SUSTAINED SOUTHERLY WINDS TODAY INTO TONIGHT. MUCH LIKE
YESTERDAY...THE HUMID SUBTROPICAL AIRMASS WILL BECOME CHILLED BY ITS
JOURNEY ACROSS THE COLD NEARSHORE OCEAN WATERS AND COULD YIELD LOW
STRATUS CLOUDS OR PATCHY SEA FOG AT TIMES. SOUTH WINDS WILL INCREASE
TO AROUND 15 KT THIS AFTERNOON...AND THEN TO 20 KNOTS TONIGHT. THESE
SURFACE WIND SPEEDS SHOULD BE LIMITED BY A STABLE BOUNDARY LAYER
FROM THE COLD UNDERLYING OCEAN SURFACE. GO 30-40 MILES OFFSHORE
WHERE WATER TEMPERATURES ARE WARMER...AND WIND SPEEDS WILL EASILY BE
ANOTHER 5-10 KNOTS HIGHER WITH MUCH ROUGHER SEAS TOO.
THE FRYING PAN SHOALS BUOY IS REPORTING 4-5 FT SEAS OVER THE PAST
COUPLE OF HOURS. SEAS WITHIN 20 MILES OF SHORE SHOULD AVERAGE 3 FT
TODAY...BUILDING TO 4-6 FT OVERNIGHT...HIGHEST IN THE FRYING PAN
SHOALS VICINITY.
SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 330 AM FRIDAY...INCREASING SOUTHWEST FLOW AHEAD OF A STRONG
COLD FRONT WILL REQUIRE A SCA HEADLINE AT SOME POINT SAT. SPEEDS
START OUT 15 TO 20 KT BUT INCREASE TO 20 TO 25 KT SAT
AFTERNOON/EVENING AS GRADIENT TIGHTENS UP. PROLONGED SOUTHWEST
FLOW WILL PROBABLY BUILD SEAS OVER 6 FT BEFORE SPEEDS REACH 25 KT.
DURATION OF SCA MAY END UP BEING RATHER BRIEF. THE FRONT WILL
STALL ALONG OR JUST OFF THE COAST WITH AN ILL-DEFINED PRESSURE
PATTERN KEEPING WINDS VARIABLE WITH SPEEDS BETWEEN 10 AND 15 KT.
WEAK WAVE OF LOW PRESSURE MOVES NORTHEAST ALONG THE STALLED
BOUNDARY PASSING EAST OF THE WATERS LATE SAT NIGHT. GRADIENT
TIGHTENS UP SUN AS THE LOW/FRONT MOVES EAST-NORTHEAST AND COLD
ADVECTION ARRIVES. STRONG OFFSHORE FLOW MAY WARRANT A BRIEF
DURATION HEADLINE SUN NIGHT INTO MON.
LONG TERM /MONDAY THROUGH TUESDAY/...
AS OF 330 AM FRIDAY...OFFSHORE FLOW WILL SLOWLY DECREASE ON MON AS
ELONGATED HIGH PRESSURE OVER THE MISSISSIPPI VALLEY SHIFTS EAST.
SPEEDS START OUT 15 TO 20 KT FROM THE WEST-NORTHWEST BUT DROP TO
10 TO 15 KT LATE MON NIGHT INTO TUE AS THEY BACK TO NORTH-
NORTHEAST. SEAS RUNNING 3 TO 5 FT DUE TO STRONG OFFSHORE FLOW WILL
SUBSIDE TO 2 TO 4 FT LATE MON INTO MON NIGHT.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...TRA
SHORT TERM...III
LONG TERM...III
AVIATION...MRR
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
1130 AM EST Fri Mar 2 2012
.UPDATE (Rest of Today)...
16Z water vapor and H4 RUC analysis shows an amplified upper level
pattern in place over the CONUS with an impressive longwave trough
from the inter-mountain west eastward to the MS valley. Ahead of
this trough our region resides under a region of weakly ridged flow
from the eastern Gulf of Mexico northward along the eastern seaboard.
At the surface, forecast area sits in a region of deep southerly
flow between a ridge of high pressure over the FL peninsula and a
strong cold front approaching the Mid/lower MS valley. Extensive
area of lower stratus is trying to mix out late this morning and
will see this stratus take on a more convective/strata-cu
configuration during the next few hours. This will allow periodic
breaks of sun the rest of the day. With the breaks of sun...will see
our temps respond. Inland areas will have a chance at reaching the
lower 80s, while coastal locations remain a bit cooler with the flow
off the shelf waters. Anticipate a generally dry afternoon under the
weak ridging, however this will begin to change tonight and
especially during the day on Saturday as showers and thunderstorms
develop into our region. Much more on the rain and potential severe
weather threat later tonight/Saturday will be found in the afternoon
forecast discussion.
&&
.AVIATION...thru 18z Sat.
Ceilings have lifted generally above IFR levels this late morning.
Patches of sun will promote diurnal mixing and expect Ceilings to
continue to rise through the afternoon. Anticipate most stations
holding at high end MVFR levels through the daylight hours, with
restrictions increasing once again within a few hours of Sunset. Do
expect a fairly widespread IFR event after midnight tonight with the
potential for periods of LIFR. Shower/storm chances will also begin
to increase before sunrise...especially up toward KDHN.
&&
.MARINE...
Areas of sea fog will continue to impact the nearshore coastal
waters into the early afternoon. Otherwise, onshore winds will
steadily increase through Saturday ahead of an approaching cold
front. This front will cross the waters on Saturday with offshore
winds behind the front reaching advisory levels in Sunday.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 79 68 75 47 67 / 10 20 100 90 10
Panama City 72 69 70 45 67 / 20 20 90 80 10
Dothan 81 66 69 39 67 / 10 40 100 60 0
Albany 81 67 70 41 68 / 10 30 100 70 10
Valdosta 80 66 75 48 67 / 10 20 100 90 20
Cross City 79 65 79 53 67 / 10 10 50 90 40
Apalachicola 74 69 74 50 66 / 10 20 90 90 10
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
AL...None.
GA...None.
FL...None.
GM...None.
&&
$$
MROCZKA
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1129 AM CST FRI MAR 2 2012
.DISCUSSION...
ISSUED 1035 AM CST FRI MAR 2 2012
SURFACE LOW CURRENTLY CENTERED JUST SOUTH OF LITCHFIELD. INITIAL
BANDS OF ELEVATED CONVECTION CONTINUE TO ARC NORTHEAST TO
CHAMPAIGN AND DANVILLE. STILL GETTING HAIL OF PEA TO DIME SIZE AT
TIMES. ASSOCIATED WARM FRONT HAS ARCHED NORTHEAST TO AROUND I-70
AND TEMPERATURES IN THE FAR SOUTHEAST CWA HAVE SURGED INTO THE 70
DEGREE RANGE...WITH DEWPOINTS AROUND 60.
LATEST HRRR SHOWING THE TRACK OF THE LOW SHOULD MOVE NORTHEAST TO
NEAR KANKAKEE BY AROUND 2 PM. HAVE BEEN SEEING RAPID DEVELOPMENT
OF SEVERE CONVECTION ACROSS SOUTHEAST MISSOURI AND SOUTHWEST
ILLINOIS IN THE WARM SECTOR...AND THIS WILL BE LIFTING NORTHEAST
ACROSS THE SOUTHEAST HALF OF THE CWA DURING THE MIDDAY AND EARLY
AFTERNOON HOURS. TORNADO WATCH CURRENTLY AFFECTING ABOUT THE
EASTERN HALF OF THE CWA...WITH THE TIME PERIOD THROUGH ABOUT 3 PM
MOST AT RISK OF SEVERE WEATHER. ACROSS THE NORTHWEST CWA...STILL
HAVE TRENDED TOWARD SOME SNOW DEVELOPMENT LATE IN THE AFTERNOON...
BUT THE DEFORMATION ZONE LIFTS QUICKLY NORTHEAST...AND HAVE BACKED
DOWN ON ANY ACCUMULATIONS UP TOWARD GALESBURG.
UPDATED ZONES/GRIDS SENT TO REFLECT LATEST CONVECTIVE TRENDS...AS
WELL AS ADJUSTING THE TEMPERATURES DUE TO THE SHARP CONTRAST
ASSOCIATED WITH THE TRACK OF THE LOW.
GEELHART
&&
.AVIATION...
ISSUED 1128 AM CST FRI MAR 2 2012
INITIAL CONCERN IS WITH CONVECTION POTENTIAL THIS AFTERNOON.
CURRENTLY LOOKS LIKE KCMI WILL BE MOST IMPACTED WITH HAIL AND
GUSTS OVER 35 KNOTS AT TIMES...WITH THE PERIOD THROUGH 21Z MOST AT
RISK. ELSEWHERE...STRONG LOW PRESSURE WILL CONTINUE MOVING
NORTHEAST ACROSS CENTRAL ILLINOIS...AND WINDS WILL BACK TO THE
NORTHWEST AND INCREASE TO 20-25 KNOTS WITH GUSTS OVER 30 KNOTS AT
TIMES. LARGE AREA OF STRATOCUMULUS WAS APPROACHING KSPI/KPIA AND
WILL OVERSPREAD THE TAF SITES THROUGH EARLY AFTERNOON WITH MVFR
CEILINGS. A LOOK AT FORECAST SOUNDINGS AT KPIA CONTINUE TO SHOW
POTENTIAL FOR SOME RAIN/SNOW MIX BY LATE AFTERNOON. MOST OF THE
PRECIPITATION AT THE TAF SITES WILL TAIL OFF BY 00Z. LAYER
HUMIDITY PLOTS SHOWING A PERIOD OF VFR CEILINGS FOR A FEW HOURS
LATE EVENING AND JUST PAST 06Z...BEFORE MVFR STRATOCUMULUS PUSHES
BACK SOUTHWARD OVERNIGHT. LOOKS LIKE THESE SHOULD LAST MOST OF THE
REMAINDER OF THE FORECAST PERIOD.
GEELHART
&&
.PREV DISCUSSION...
ISSUED 320 AM CST FRI MAR 2 2012
YET ANOTHER POWERFUL STORM SYSTEM TO IMPACT IL ON THE HEALS OF A
STRONG STORM SYSTEM THAT AFFECTED THE AREA THIS PAST TUE NIGHT.
FORECAST CONCERN IS SEVERE WEATHER THREAT WITH MODERATE RISK IN SE
IL TODAY AND SLIGHT RISK AS FAR NW AS I-55. ANOTHER ISSUE IS HOW
STRONG GRADIENT WINDS GET DURING THIS AFTERNOON/EVENING AND IF A
WIND ADVISORY IS NEEDED. YET ANOTHER CONCERN IS SNOWFALL AMOUNTS
NW OF THE IL RIVER THIS AFTERNOON AND EARLY EVENING. 00Z MODELS
COMING INTO BETTER AGREEMENT OF DEEPENING LOW PRESSURE LIFTING NE
INTO THE HEART OF IL BY 18Z/NOON TODAY AND INTO NE LOWER MI BY
SAGINAW BAY BY MIDNIGHT TONIGHT. MODELS ALSO CONTINUE TO SHOW
STRONG UPPER LEVEL TROF DIGGING OVER THE EASTERN STATES THIS
WEEKEND BRINGING MUCH COOLER WEATHER. EXTENDED MODELS DIFFER WITH
HANDLING NEXT WEATHER SYSTEM DURING WED-FRI TIME FRAME AND
CONFIDENCE IS LOW WITH FORECAST THEN.
SHORT TERM...TODAY THROUGH SUNDAY NIGHT
PREDAWN SURFACE MAP SHOWS 995 MB LOW PRESSURE OVER EXTREME NE OK
WITH A FRONTAL BOUNDARY EXTENDING NE INTO CENTRAL IL. TRUE WARM
FRONT WAS OVER SOUTHERN MO/TN WITH MOIST DEWPOINTS IN WARM SECTOR
SOUTH OF WARM FRONT WITH DEWPOINTS IN THE 50S/60S. SHOWERS AND
THUNDERSTORMS HAVE DEVELOPED RECENTLY OVER SW KY...FAR SOUTHERN IL
SOUTH OF I-64 AND OVER SW MO AND MOVING QUICKLY NE.
LOW PRESSURE TO EJECT NE INTO CENTRAL IL NEAR DECATUR BY 18Z/NOON
THEN DEEPEN BELOW 990 MB AT IT LIFTS TOWARD THE MI/IN/OH BORDER BY
SUNSET SWINGING A COLD FRONT THROUGH EASTERN IL THIS AFTERNOON.
WARM AIR ADVECTION DRIVEN CONVECTION TO SPREAD QUICKLY NE AHEAD OF
WARM FRONT OVER CENTRAL/SE IL THIS MORNING WITH HAIL POSSIBLE AND
COULD BE SEVERE HAIL SOUTH OF I-72. STRONG/FAST MOVING SUPERCELLS
POSSIBLE LATER THIS MORNING AND THROUGH MID AFTERNOON SE OF I-55
WITH RISK OF TORNADOES AS WELL ESPECIALLY IN SE IL FROM I-70 SE.
LARGE HAIL AND DAMAGING WIND IS 45% RISK IN SE IL WITH TORNADO
THREAT 15%. EVEN A 10% RISK OF EF2 OR STRONGER TORNADOES IN SE IL
ALONG WITH 10% RISK OF 2 INCH OR LARGER HAIL AND 75 MPH WINDS OR
STRONGER. AS LOW PRESSURE DEEPENS AND PULLS AWAY FROM CENTRAL IL
DURING THIS AFTERNOON...GRADIENT WINDS REALLY PICK UP WITH BUFKIT
SHOWING MOMENTUM TRANSFER OF 40 KTS OR HIGHER FROM MID AFTERNOON
INTO EARLY EVENING OVER EASTERN IL AND WILL ISSUE A WIND ADIVSORY
THERE FROM 2-8 PM. HIGHS TODAY RANGE FROM THE MID 40S BY GALESBURG
TO NEAR 70F BY LAWRENCEVILLE...WITH FALLING TEMPS NW OF I-55 DURING
THIS AFTERNOON.
IN ADDITION TO THE SEVERE WEATHER THREAT TODAY...WILL SEE RAIN
MIXING WITH AND CHANGING TO SNOW NW OF THE IL RIVER DURING 2-6 PM
AND THEN DIMINISH EARLY THIS EVENING. HAVE 1-2 INCHES FROM
GALESBURG TO STARK COUNTIES NW. MODELS HAVE TRENDED FURTHER SOUTH
WITH THIS DEFORMATION ZONE INTO AREAS FROM PEORIA NORTH THIS
AFTERNOON AND EARLY EVENING. PRECIPITATION SHOULD MOSTLY BE
EXITING CENTRAL IL AFTER 9 PM TONIGHT AS STRONG LOW PRESSURE PULLS
QUICKLY AWAY.
STRONG UPPER LEVEL TROF TO DIG INTO THE EASTERN STATES THIS
WEEKEND BRINGING MUCH COLDER AIR INTO THE REGION ALONG WITH A FAIR
AMOUNT OF LOW CLOUDS. CONTINUES CHANCES OF LIGHT RAIN/SNOW SHOWERS
SUNDAY AND SUNDAY EVENING BUT NOT ACCUMULATIONS AT THIS TIME WITH
CLIPPER SYSTEM. INCREASED WIND SPEEDS THIS WEEKEND WITH FAIRLY
TIGHT PRESSURE GRADIENT OVER AREA.
LONG TERM...MONDAY THROUGH FRIDAY
NOT TOO MANY CHANGES MADE TO THE EXTENDED FORECAST WITH DRY
CONDITIONS EXPECTED MONDAY THROUGH TUE NIGHT AS TEMPS WARM UP FROM
MON-WED AS UPPER LEVEL HEIGHTS RISE OVER IL. BIG DIFFERENCE WITH
GFS...GEM AND ECMWF MODELS FOR NEXT WEATHER SYSTEM BUT DOES
APPEARS WED TO BE DRIER THAN EARLIER THOUGHT AND TRIMMED BACK POPS
TO KEEP EASTERN IL DRY WED. SHOWERS AND POSSIBLE THUNDERSTORMS
FROM WED NIGHT THRU THU AND POSSIBLY LINGERING SHOWERS INTO
FRIDAY. MODELS DIVERGE WITH HOW FAST TEMPS COOL LATER NEXT WEEK
AND USED A BLEND FOR NOW SHOWING A COOLING TREND LATE IN THE WEEK.
HUETTL
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 8 PM CST THIS EVENING FOR ILZ044>046-054>057-
061>063-066>068-071>073.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1035 AM CST FRI MAR 2 2012
.DISCUSSION...
ISSUED 1035 AM CST FRI MAR 2 2012
SURFACE LOW CURRENTLY CENTERED JUST SOUTH OF LITCHFIELD. INITIAL
BANDS OF ELEVATED CONVECTION CONTINUE TO ARC NORTHEAST TO
CHAMPAIGN AND DANVILLE. STILL GETTING HAIL OF PEA TO DIME SIZE AT
TIMES. ASSOCIATED WARM FRONT HAS ARCHED NORTHEAST TO AROUND I-70
AND TEMPERATURES IN THE FAR SOUTHEAST CWA HAVE SURGED INTO THE 70
DEGREE RANGE...WITH DEWPOINTS AROUND 60.
LATEST HRRR SHOWING THE TRACK OF THE LOW SHOULD MOVE NORTHEAST TO
NEAR KANKAKEE BY AROUND 2 PM. HAVE BEEN SEEING RAPID DEVELOPMENT
OF SEVERE CONVECTION ACROSS SOUTHEAST MISSOURI AND SOUTHWEST
ILLINOIS IN THE WARM SECTOR...AND THIS WILL BE LIFTING NORTHEAST
ACROSS THE SOUTHEAST HALF OF THE CWA DURING THE MIDDAY AND EARLY
AFTERNOON HOURS. TORNADO WATCH CURRENTLY AFFECTING ABOUT THE
EASTERN HALF OF THE CWA...WITH THE TIME PERIOD THROUGH ABOUT 3 PM
MOST AT RISK OF SEVERE WEATHER. ACROSS THE NORTHWEST CWA...STILL
HAVE TRENDED TOWARD SOME SNOW DEVELOPMENT LATE IN THE AFTERNOON...
BUT THE DEFORMATION ZONE LIFTS QUICKLY NORTHEAST...AND HAVE BACKED
DOWN ON ANY ACCUMULATIONS UP TOWARD GALESBURG.
UPDATED ZONES/GRIDS SENT TO REFLECT LATEST CONVECTIVE TRENDS...AS
WELL AS ADJUSTING THE TEMPERATURES DUE TO THE SHARP CONTRAST
ASSOCIATED WITH THE TRACK FO THE LOW.
GEELHART
&&
.AVIATION...
ISSUED 545 AM CST FRI MAR 2 2012
VFR CONDITIONS EARLY THIS MORNING WILL DETERIORATE DURING MID AND
LATE MORNING AS SHOWERS AND THUNDERSTORMS RACE QUICKLY NE INTO
CENTRAL IL. IFR TO MVFR CEILINGS AND VISIBILITIES TO DEVELOP
BY MIDDAY AND CONTINUE THIS AFTERNOON. THUNDERSTORMS CONFINED TO
AREAS FROM I-55 EAST AND DID NOT MENTION THUNDER AT PIA. RAIN TO
MIX WITH OR CHANGE TO SNOW LATE THIS AFTERNOON AT PIA AND DIMINISH
EARLY THIS EVENING...THOUGH HEAVIER WET SNOW SHOULD STAY NORTH OF
PIA. ENE WINDS 5-10 KTS EARLY THIS MORNING TO TURN WEST THIS
AFTERNOON AND INCREASE TO 15 TO 25 KTS WITH GUSTS OF 25 TO 35 KTS
AND THEN GRADUALLY DIMINISH TO AROUND 15 KTS LATER THIS EVENING
AND OVERNIGHT. LOW CLOUDS TO DECREASE EARLY THIS EVENING BUT MVFR
CEILINGS TO PUSH SE INTO CENTRAL IL DURING OVERNIGHT.
995 MB LOW PRESSURE OVER SW MO TO MOVE NE ALONG A FRONTAL BOUNDARY
INTO CENTRAL IL...REACHING NEAR DEC BY 18Z/NOON TODAY...AND TO
NEAR THE LOWER MI/IN BORDER BY SUNSET AND SWEEP A COLD FRONT
THROUGH EASTERN IL INCLUDING CMI EARLY THIS AFTERNOON. LOW
PRESSURE DEEPENS FURTHER TO NEAR SAGINAW BAY IN NE LOWER MI BY
MIDNIGHT TONIGHT AND TO GEORGIAN BAY BY 12Z/6 AM SAT. BLUSTERY
WEST WINDS WILL CONTINUE TONIGHT INTO SAT WITH TIGHT PRESSURE
GRADIENT REMAINING OVER CENTRAL IL.
HUETTL
&&
.PREV DISCUSSION...
ISSUED 320 AM CST FRI MAR 2 2012
YET ANOTHER POWERFUL STORM SYSTEM TO IMPACT IL ON THE HEALS OF A
STRONG STORM SYSTEM THAT AFFECTED THE AREA THIS PAST TUE NIGHT.
FORECAST CONCERN IS SEVERE WEATHER THREAT WITH MODERATE RISK IN SE
IL TODAY AND SLIGHT RISK AS FAR NW AS I-55. ANOTHER ISSUE IS HOW
STRONG GRADIENT WINDS GET DURING THIS AFTERNOON/EVENING AND IF A
WIND ADVISORY IS NEEDED. YET ANOTHER CONCERN IS SNOWFALL AMOUNTS
NW OF THE IL RIVER THIS AFTERNOON AND EARLY EVENING. 00Z MODELS
COMING INTO BETTER AGREEMENT OF DEEPENING LOW PRESSURE LIFTING NE
INTO THE HEART OF IL BY 18Z/NOON TODAY AND INTO NE LOWER MI BY
SAGINAW BAY BY MIDNIGHT TONIGHT. MODELS ALSO CONTINUE TO SHOW
STRONG UPPER LEVEL TROF DIGGING OVER THE EASTERN STATES THIS
WEEKEND BRINGING MUCH COOLER WEATHER. EXTENDED MODELS DIFFER WITH
HANDLING NEXT WEATHER SYSTEM DURING WED-FRI TIME FRAME AND
CONFIDENCE IS LOW WITH FORECAST THEN.
SHORT TERM...TODAY THROUGH SUNDAY NIGHT
PREDAWN SURFACE MAP SHOWS 995 MB LOW PRESSURE OVER EXTREME NE OK
WITH A FRONTAL BOUNDARY EXTENDING NE INTO CENTRAL IL. TRUE WARM
FRONT WAS OVER SOUTHERN MO/TN WITH MOIST DEWPOINTS IN WARM SECTOR
SOUTH OF WARM FRONT WITH DEWPOINTS IN THE 50S/60S. SHOWERS AND
THUNDERSTORMS HAVE DEVELOPED RECENTLY OVER SW KY...FAR SOUTHERN IL
SOUTH OF I-64 AND OVER SW MO AND MOVING QUICKLY NE.
LOW PRESSURE TO EJECT NE INTO CENTRAL IL NEAR DECATUR BY 18Z/NOON
THEN DEEPEN BELOW 990 MB AT IT LIFTS TOWARD THE MI/IN/OH BORDER BY
SUNSET SWINGING A COLD FRONT THROUGH EASTERN IL THIS AFTERNOON.
WARM AIR ADVECTION DRIVEN CONVECTION TO SPREAD QUICKLY NE AHEAD OF
WARM FRONT OVER CENTRAL/SE IL THIS MORNING WITH HAIL POSSIBLE AND
COULD BE SEVERE HAIL SOUTH OF I-72. STRONG/FAST MOVING SUPERCELLS
POSSIBLE LATER THIS MORNING AND THROUGH MID AFTERNOON SE OF I-55
WITH RISK OF TORNADOES AS WELL ESPECIALLY IN SE IL FROM I-70 SE.
LARGE HAIL AND DAMAGING WIND IS 45% RISK IN SE IL WITH TORNADO
THREAT 15%. EVEN A 10% RISK OF EF2 OR STRONGER TORNADOES IN SE IL
ALONG WITH 10% RISK OF 2 INCH OR LARGER HAIL AND 75 MPH WINDS OR
STRONGER. AS LOW PRESSURE DEEPENS AND PULLS AWAY FROM CENTRAL IL
DURING THIS AFTERNOON...GRADIENT WINDS REALLY PICK UP WITH BUFKIT
SHOWING MOMENTUM TRANSFER OF 40 KTS OR HIGHER FROM MID AFTERNOON
INTO EARLY EVENING OVER EASTERN IL AND WILL ISSUE A WIND ADIVSORY
THERE FROM 2-8 PM. HIGHS TODAY RANGE FROM THE MID 40S BY GALESBURG
TO NEAR 70F BY LAWRENCEVILLE...WITH FALLING TEMPS NW OF I-55 DURING
THIS AFTERNOON.
IN ADDITION TO THE SEVERE WEATHER THREAT TODAY...WILL SEE RAIN
MIXING WITH AND CHANGING TO SNOW NW OF THE IL RIVER DURING 2-6 PM
AND THEN DIMINISH EARLY THIS EVENING. HAVE 1-2 INCHES FROM
GALESBURG TO STARK COUNTIES NW. MODELS HAVE TRENDED FURTHER SOUTH
WITH THIS DEFORMATION ZONE INTO AREAS FROM PEORIA NORTH THIS
AFTERNOON AND EARLY EVENING. PRECIPITATION SHOULD MOSTLY BE
EXITING CENTRAL IL AFTER 9 PM TONIGHT AS STRONG LOW PRESSURE PULLS
QUICKLY AWAY.
STRONG UPPER LEVEL TROF TO DIG INTO THE EASTERN STATES THIS
WEEKEND BRINGING MUCH COLDER AIR INTO THE REGION ALONG WITH A FAIR
AMOUNT OF LOW CLOUDS. CONTINUES CHANCES OF LIGHT RAIN/SNOW SHOWERS
SUNDAY AND SUNDAY EVENING BUT NOT ACCUMULATIONS AT THIS TIME WITH
CLIPPER SYSTEM. INCREASED WIND SPEEDS THIS WEEKEND WITH FAIRLY
TIGHT PRESSURE GRADIENT OVER AREA.
LONG TERM...MONDAY THROUGH FRIDAY
NOT TOO MANY CHANGES MADE TO THE EXTENDED FORECAST WITH DRY
CONDITIONS EXPECTED MONDAY THROUGH TUE NIGHT AS TEMPS WARM UP FROM
MON-WED AS UPPER LEVEL HEIGHTS RISE OVER IL. BIG DIFFERENCE WITH
GFS...GEM AND ECMWF MODELS FOR NEXT WEATHER SYSTEM BUT DOES
APPEARS WED TO BE DRIER THAN EARLIER THOUGHT AND TRIMMED BACK POPS
TO KEEP EASTERN IL DRY WED. SHOWERS AND POSSIBLE THUNDERSTORMS
FROM WED NIGHT THRU THU AND POSSIBLY LINGERING SHOWERS INTO
FRIDAY. MODELS DIVERGE WITH HOW FAST TEMPS COOL LATER NEXT WEEK
AND USED A BLEND FOR NOW SHOWING A COOLING TREND LATE IN THE WEEK.
HUETTL
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM 2 PM THIS AFTERNOON TO 8 PM CST THIS EVENING
FOR ILZ044>046-054>057-061>063-066>068-071>073.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1010 AM CST FRI MAR 2 2012
.DISCUSSION...
357 AM CST
A VERY DIFFICULT FORECAST SITUATION SHAPING UP FOR TODAY AND TONIGHT
WITH A COMBINATION OF WINTER WEATHER AND CONVECTIVE WEATHER TO
AFFECT NORTHERN ILLINOIS AND NORTHWEST INDIANA.
A SOUTHERN STREAM LOW IS TAKING SHAPE OVER THE SOUTHERN PLAINS. THE
MODELS ARE FINALLY SETTING INTO A SOLUTION OF TRACKING THE SFC LOW
FROM CENTRAL OKLAHOMA...THROUGH SOUTHERN MISSOURI THIS MORNING AND
INTO CENTRAL ILLINOIS BY AROUND NOON AND THROUGH NORTHERN INDIANA
AND INTO SOUTHERN LOWER MICHIGAN BY EARLY THIS EVENING. THE
SITUATION IS COMPLICATED BY A NORTHERN STREAM SHORT WAVE DROPPING
OUT OF THE NORTHERN PLAINS AND INTO THE WESTERN GREAT LAKES. THE
GUIDANCE IS ADVERTISING PHASING OF THE NORTHERN STREAM SYSTEM WITH
THE SOUTHERN STREAM LOW WHICH WILL LEAD TO RAPID DEEPENING OF THE
SYSTEM. THE RAPID DEEPENING OF THE LOW SHOULD NOT TAKE PLACE UNTIL
LATE THIS AFTERNOON AND INTO THE EVENING...WHEN THE LOW IS MOVING
THROUGH NORTHERN INDIANA AND INTO LOWER MICHIGAN. FOR THE
THUNDERSTORM THREAT...THE MOST LIKELY TIMING AND LOCATION OF THUNDER
WILL BE OVER THE SOUTHERN AND EASTERN PORTIONS OF THE CWA...THOUGH
THERE IS A CHANCE THAT SOME THUNDER CAN DEVELOP AS FAR NORTH AS THE
FAR SOUTHEASTERN CHICAGO SUBURBS. GIVEN THE VERY DYNAMIC SITUATION
SETTING UP...THE FAR SOUTHEASTERN PORTIONS OF THE CWA...ROUGHLY
SOUTH OF THE KANKAKEE RIVER ARE IN A SLIGHT RISK AREA FOR SEVERE
WEATHER WITH POSSIBLE DISCRETE SUPERCELL DEVELOPMENT AND THE MOST
LIKELY TIMING FOR STRONG TO SEVERE THUNDERSTORMS WILL BE DURING THE
LATE AFTERNOON HOURS.
THE WINTER WEATHER PICTURE IS A LITTLE MUDDLED BY SURFACE
TEMPERATURES AND THE GUIDANCE IS SHOWING SOME UNCERTAINTY TO THE
LOCATION OF THE RAIN/SNOW LINE. THIS MORNING...HAVE TRENDED CLOSELY
TO THE NAM SOLUTION...THOUGH THE TRACK OF THE MAIN SFC LOW IS VERY
SIMILAR SIMILAR IN MUCH OF THE SHORT RANGE GUIDANCE. FEEL FAIRLY
CONFIDENT IN A DEFORMATION ZONE FORMING NORTHWEST OF THE SFC LOW
TRACK...INITIALLY OVER ERN IOWA BY ARND NOON AND THEN SHIFT EWD INTO
THE ROCKFORD AREA THROUGH THE AFTERNOON. WITH PRECIPITABLE WATER
AMOUNTS EXPECTED TO APPROACH THREE QUARTERS OF AN INCH INVOF THE
DEFORMATION BAND...QPF VALUES SHOULD BE RELATIVELY HIGH...AND
ANTICIPATE CLOSE TO AN INCH OF STORM TOTAL LIQUID QPF FOR THE
DURATION OF THE EVENT. TOTAL SNOWFALL IN THE MAIN DEFORMATION BAND
HAS BEEN TOUGH TO GET A HANDLE ON GIVEN THE UNCERTAINTY IN THE
LOCATION OF THE RAIN/SNOW LINE AND HOW LARGE OF A TRANSITION ZONE
THERE WILL BE BETWEEN THE AREA OF ALL RAIN AND ALL SNOW. HAVE
MAINTAINED A FAIRLY BROAD TRANSITION ZONE IN THE GRIDS TO REFLECT
THE UNCERTAINTY. ONE LIMITING FACTOR FOR TOTAL ACCUMULATION WILL BE
THE INITIAL RELATIVELY WARM ENVIRONMENT AND THE TIME IT WILL TAKE
FOR THE COLDER AIR TO FILTER IN BEHIND THE SFC LOW. AT THIS POINT
HAVE GONE WITH RELATIVELY LOW RAIN/SNOW RATIOS. AT THIS
POINT...ANTICIPATE THAT THE BAND OF HEAVIEST ACCUMULATION WILL
EXTEND FROM NEAR DIXON TO ROCKFORD...WITH A BAND OF 3 TO 5 INCHES
POSSIBLE. LIGHTER AMOUNTS SHOULD EXTEND TO THE SOUTH AND
EAST...WITH 1 TO 2 INCHES NEAR THE I-88 CORRIDOR...INCLUDING THE
CHICAGO AREA. SOME LIGHTER AMOUNTS ARE POSSIBLE AS FAR SOUTH AS
I-80. GIVEN THE UNCERTAINTY OF THE TOTAL SNOWFALL AMOUNTS...WILL
LET THE WINTER STORM WATCH RIDE FOR NOW...AND WAIT TO SEE HOW
QUICKLY THE SYSTEM DEEPENS BEFORE MAKING A FINAL DECISION ON WHETHER
TO GO WITH A WINTER STORM WARNING OR AN ADVISORY.
STRONG WINDS SHOULD ALSO BE A CONCERN LATE THIS AFTERNOON AND EARLY
THIS EVENING...ESPECIALLY FOR LOCATIONS EAST OF THE I-55 CORRIDOR AS
THE SFC LOW DEEPENS AS IT TRACKS THROUGH INDIANA. AT THIS
POINT...DO NOT ANTICIPATE THE NEED FOR A WIND ADVISORY...BUT GUSTS
OF 30 TO 35 MPH...AND AN OCCASIONAL GUST TO 40 MPH...ARE LIKELY.
THIS WEEKEND THROUGH MID WEEK...
CYCLONIC FLOW WILL BE THE DOMINANT WEATHER WORD THROUGH THE WEEKEND.
BEHIND THE SYSTEM THAT WILL IMPACT THE REGION TODAY WILL BE A
SHEARED VORT LOBE THAT WILL MOVE FROM NORTHWEST TO SOUTHEAST ACROSS
THE CWA BY SATURDAY MORNING. THIS MAY BRING SOME LIGHT SNOW SHOWERS
TO AREAS NORTH OF INTERSTATE 80 THROUGHOUT THE DAY ON SATURDAY AND
SATURDAY NIGHT. MOISTURE WILL BE RELATIVELY SHALLOW AND FORCING WILL
BE WEAK...AND NOT EXPECTING MUCH BEYOND LIGHT SNOW SHOWERS TO A
LIGHT DUSTING. THE COLD NORTHWEST FLOW WILL KEEP TEMPERATURES DOWN
AND BELOW NORMAL THROUGH THE WEEKEND...AND A CONSTANT STRATUS DECK
WILL KEEP THOSE TEMPERATURES LOCKED AS IS. THE OFF AND ON CHANCES
FOR LIGHT SNOW SHOWERS WILL ALSO CONTINUE SUNDAY AS ANOTHER RIPPLE
IN THE FLOW SHOOTS DOWN THROUGH THE NORTHERN PLAINS AND ACROSS
NORTHERN ILLINOIS AND NORTHWESTERN INDIANA THROUGH THAT TIME. THE
FLIP BACK TO SPRING WILL COME CHARGING IN JUST IN
TIME FOR THE WORK WEEK. BY MONDAY AFTERNOON...AN EXPANSIVE AREA OF
HIGH PRESSURE WILL SHIFT EAST OF THE MID MISSISSIPPI VALLEY REGION
AND ACROSS THE OHIO VALLEY...ALLOWING WINDS TO BECOME SOUTHERLY.
TIGHTENING GRADIENT FLOW AT THE SURFACE AND STRONG WAA WILL SUPPORT
HIGHS TUESDAY QUICKLY JUMPING TO THE UPPER 50S TO LOW TO MID 60S.
WITH OVERNIGHT LOWS IN THE LOWER 40S. CURRENT RECORDS FOR ROCKFORD
AND OHARE FOR TUESDAY AND WEDNESDAY ARE 70 AND 78 RESPECTIVELY AND
DONT EXPECT ANY THREAT TO THOSE NUMBERS.
THE NEXT UPPER LEVEL WAVE WILL APPROACH THE REGION CLOSER TO
WEDNESDAY EVENING /SLOWER THAN EARLIER FORECASTS/ BRINGING WITH IT
THE INCREASED CHANCES FOR SHOWERS. A WEAKENING UPPER LEVEL TROUGH
WILL HELP TO PUSH THROUGH A COLD FRONT OVERNIGHT ON THURSDAY. AT
THIS POINT IT IS LOOKING LIKE ANY THUNDER THREAT WILL BE MARGINAL.
KREIN/SHEA
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* CIGS LOWERING TO IFR BY MID AFTERNOON AND PERSISTING INTO
EVENING IN PRECIPITATION.
* RAIN SPREADING ACROSS TERMINALS SHORTLY AFTER 17Z.
* RAIN CHANGING TO SNOW LATE THIS AFTERNOON...WITH SNOW BEING
MODERATE TO POSSIBLY HEAVY AT TIMES INTO EARLY EVENING.
* A SMALL CHANCE FOR ICE PELLETS DURING THE RAIN TO SNOW
CHANGEOVER LATE THIS AFTERNOON.
* WINDS BACKING TO THE NORTH THIS AFTERNOON THEN BECOMING GUSTY
AND BACKING TO THE WEST BY MID EVENING.
//DISCUSSION...UPDATED 16Z...
ONLY MADE SOME MINOR CHANGES TO GOING FORECAST IN NEAR
TERM...MAINLY WITH RESPECT MOVING TIMING OF RAIN UP A COUPLE OF
HOURS WITH RAIN ALREADY SPREADING INTO THE SOUTHERN PARTS OF
CHICAGO METRO FROM THE SOUTH. TIMING OF RAIN/SNOW CHANGEOVER...
THE POTENTIAL FOR A PERIOD OF MODERATE/HEAVY SNOW INTO EARLY
EVENING...AND IFR/LIFR CONDITIONS ALL CONTINUE TO LOOK APPROPRIATE
BASED ON 12Z NAM WHICH REMAINS CONSISTENT WITH PREVIOUS THINKING.
THUNDER WILL BE LIKELY JUST OFF TO THE SOUTH OF THE TERMINALS
MIDDAY THROUGH AFTERNOON. RECENT HRRR RUNS THIS MORNING CONTINUE
TO DEPICT SOME POTENTIAL FOR CELLULAR CONVECTION INTO CHI AREA
AROUND 20Z...BUT BETTER POTENTIAL LOOKS TO BE ALONG/SOUTH OF A
PNT-GYY LINE AT THIS TIME.
RATZER
PREVIOUS DISCUSSION FROM 12Z...
A VERY ACTIVE PERIOD OF WEATHER IMPACTING AVIATION IS EXPECTED
ACROSS THE REGION THIS AFTERNOON AND EVENING. THIS WILL BE DUE TO
DEEPENING LOW PRESSURE MOVING NORTHEAST FROM SOUTHERN MO THIS
MORNING TO LOWER MI BY EVENING. THROUGH THIS MORNING...THERE WILL
BE MINIMAL IMPACTS WITH MID-LEVEL CLOUD COVER AND POSSIBLY A
PASSING SPRINKLE OR ISOLATED LIGHT SHOWER.
AS THE ENTIRE WEATHER SYSTEM BECOMES SIGNIFICANTLY BETTER
ORGANIZED THIS AFTERNOON...PRECIPITATION WILL SPREAD OVER NORTHERN
IL AND NORTHWEST IN. THIS WILL START AS RAIN AT ALL TAF SITES.
CIGS SHOULD QUICKLY DROP TO IFR OR LOW MVFR WITHIN AN HOUR OR TWO
OF THE PRECIP BEGINNING. WITH THE SYSTEM DEEPENING...COOLER AIR
WILL ALSO BE MORE RAPIDLY ENTRAINED INTO THE SYSTEM...AS WELL AS
DYNAMIC COOLING OCCURRING. THIS WILL TRANSITION RAIN TO A WET AND
POTENTIALLY HEAVY SNOW ACROSS NORTH CENTRAL IL...INCLUDING
RFD...DURING THE MIDDLE OF THIS AFTERNOON...AND ACROSS CHICAGO
AREA AIRPORTS LATE THIS AFTERNOON. THERE EVEN COULD BE A BRIEF
PERIOD OF ICE PELLETS DURING THE CHANGEOVER...BUT CONFIDENCE IN
THIS IS LOW. IN ADDITION...THUNDER IS POSSIBLE AT CHICAGO AREA
AIRPORTS AND GARY DURING THIS TIME. THE MOST ROBUST THUNDERSTORMS
ARE EXPECTED TO REMAIN SOUTH AND SOUTHEAST OF CHICAGO.
SNOWFALL RATES DURING THE TWO TO THREE HOURS AFTER TRANSITION WILL
BE MODERATE TO POTENTIALLY HEAVY...ESPECIALLY AT RFD. THE QUICK
FORWARD PROGRESS OF THE SYSTEM WILL HELP TO TAPER SNOW QUICKLY BY
MID EVENING FROM WEST TO EAST. WHILE SNOWFALL MAY ONLY LAST A FEW
HOURS...THE MODERATE TO POTENTIALLY HEAVY /GREATER THAN ONE INCH
PER HOUR/ RATES WILL LEAD TO QUICK ACCUMULATION. THIS IS
ESPECIALLY TRUE AT RFD...WHERE FOUR TO SIX INCHES ARE EXPECTED. AS
FOR AMOUNTS ANTICIPATED AT OTHER AIRFIELDS...TWO TO FOUR AT
DPA...ONE TO THREE AT ORD...AROUND ONE AT MDW...AND LESS THAN ONE
AT GYY.
WITH THE SIGNIFICANT INTENSIFICATION OF THE ENTIRE LOW PRESSURE
AREA THIS AFTERNOON AND EVENING...THE ENTIRE ATMOSPHERIC WIND
FIELD WILL RESPOND WITH A RAPID INCREASE IN MAGNITUDE. SURFACE
WINDS WILL BACK TO THE NORTH THEN NORTHWEST THROUGH THIS
AFTERNOON. THESE WILL BECOME GUSTY...ESPECIALLY LATE IN THE
AFTERNOON AND EVENING. HAVE GONE ABOVE MODEL FORECASTS FOR WINDS
WITH SUCH A RAPIDLY DEEPENING SYSTEM AND THE PATH IT IS TAKING.
WINDS ALOFT...IN THE 2000 TO 4000 FT LAYER LATE THIS AFTERNOON AND
EVENING...WILL LIKELY BE BETWEEN 35 AND 50 KTS ACROSS CHICAGO INTO
NORTHWEST INDIANA.
CIGS ARE EXPECTED TO IMPROVE LATER THIS EVENING...AND MAY COME UP
EVEN FASTER THAN THE TAF INDICATES.
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* HIGH CONFIDENCE IN IFR CIGS DEVELOPING BY LATE AFTERNOON.
* HIGH CONFIDENCE IN RAIN CHANGING TO SNOW. HIGH CONFIDENCE IN AT
LEAST MODERATE RATES OF SNOWFALL AT ORD...WITH MEDIUM CONFIDENCE
AT MDW. MEDIUM CONFIDENCE IN TIMING OF TRANSITION AT BOTH
AIRPORTS.
* LOW CONFIDENCE IN ICE PELLET CHANCES. HIGH CONFIDENCE THAT IF
ICE PELLETS OCCUR THAT THE PERIOD WOULD BE BRIEF.
* HIGH CONFIDENCE IN WIND TRENDS. MEDIUM CONFIDENCE IN SPEEDS AND
GUSTS.
//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...
* SUNDAY...CHANCE OF MVFR WITH SNOW SHOWERS.
* MONDAY AND TUESDAY...VFR.
* WEDNESDAY...GUSTY SOUTHERLY WINDS. CHANCE OF RAIN SHOWERS.
* THURSDAY...CHANCE OF MVFR IN RAIN.
MTF
&&
.MARINE...
241 AM CST
STRONG LOW PRESSURE SYSTEM TO IMPACT THE REGION TODAY BRINGING
STRONG GALES AND POSSIBLY STORM FORCE WINDS TO THE LOWER HALF OF
LAKE MICHIGAN. THIS MORNING LOW PRESSURE IS CENTERED OVER CENTRAL
OKLAHOMA AND IS FORECAST TO LIFT NORTHEAST AND RAPIDLY DEEPEN. THIS
LOW WILL PASS JUST SOUTH OF LAKE MICHIGAN LATE THIS EVENING...
CONTINUING TO DEEPEN AS IT PUSHES ACROSS MICHIGAN TONIGHT. TIGHT
PRESSURE GRADIENT DEVELOPS ON THE NORTHWEST QUADRANT OF THE LOW WITH
VERY STRONG PRESSURE FALL/RISE COUPLET HELPING TO FURTHER ENHANCE
WINDS ACROSS THE SOUTHERN HALF OF THE LAKE. GUIDANCE SUGGESTS WINDS
OF 50 TO 55 KTS AT THE TOP OF THE MIXED LAYER FOR A BRIEF PERIOD
WHICH COULD MIX DOWN TO THE LAKE SURFACE. OUTSIDE OF THIS VERY SHORT
WINDOW WHERE STORM FORCE WINDS ARE POSSIBLE...MAINLY LOOKING AT HIGH
END GALE EVENT WITH WINDS 40 TO 45 KT FROM THIS EVENING THROUGH
EARLY SATURDAY MORNING. WILL UPGRADE THE GALE WATCH TO A WARNING AND
ALSO EXPAND INTO THE NEARSHORE WATERS.
WINDS DIMINISH SUNDAY AND MONDAY AS SURFACE RIDGE MOVES ACROSS THE
LAKE. WINDS INCREASE AGAIN TUESDAY AND WEDNESDAY AS ANOTHER LOW
PRESSURE SYSTEM PUSHES EAST ACROSS THE CANADIAN PRAIRIES THEN INTO
HUDSON BAY. BROAD HIGH PRESSURE WILL THEN DEVELOP ACROSS THE PLAINS
AND UPPER MIDWEST TO END OUT THE WEEK. BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WINTER WEATHER ADVISORY...ILZ013-ILZ014...3 PM FRIDAY TO
MIDNIGHT SATURDAY.
WINTER WEATHER ADVISORY...ILZ010-ILZ011-ILZ012...3 PM FRIDAY TO
9 PM FRIDAY.
WINTER STORM WATCH...ILZ003-ILZ004-ILZ008...3 PM FRIDAY TO 9 PM
FRIDAY.
WINTER STORM WATCH...ILZ005-ILZ006...3 PM FRIDAY TO MIDNIGHT
SATURDAY.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-
LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...5 PM
FRIDAY TO 3 PM SATURDAY.
GALE WARNING...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745...5 PM
FRIDAY TO 3 AM SATURDAY.
SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 5 PM FRIDAY.
SMALL CRAFT ADVISORY...LMZ743-LMZ744-LMZ745...3 PM FRIDAY TO 5
PM FRIDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
450 PM EST FRI MAR 2 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...A STRONG LOW PRESSURE SYSTEM WILL KEEP STORMS IN THE
AREA FOR THE NEXT FEW HOURS...THEN STRONG WINDS SHOULD REMAIN IN ITS
WAKE INTO THE NIGHT. THIS WILL USHER IN MUCH COLDER AIR FOR THE
WEEKEND BEFORE UPPER RIDGING BRINGS WARMER AIR AND ANOTHER SYSTEM
MOVES IN WITH CHANCES FOR RAIN MID WEEK.
&&
.NEAR TERM /THIS AFTERNOON THROUGH TONIGHT/...
SEVERE THREAT CONTINUES. THUNDERSTORMS...SOME SEVERE...ONGOING
ACROSS MUCH OF THE FORECAST AREA. THE COLD FRONT LAGS THESE BY QUITE
A BIT AND THERE IS CLEARING IN THE MIDDLE WHERE RAPID REFRESH IS
SHOWING SOME REDEVELOPMENT SO MAY NOT BE ABLE TO CLEAR OUT RISK
UNTIL A BIT LATER. STILL LOOKS LIKE EVERYTHING WILL BE OUT OF THE
AREA BY 0Z BUT WILL CONTINUE TO CARRY A CHANCE IN THE EAST SINCE
TORNADO WATCH THERE RUNS UNTIL 2Z BUT EXPECT TO BE ABLE TO CANCEL
THAT EARLY. WINDS WILL PICK UP BEHIND THE FRONT WITH TIGHT PRESSURE
GRADIENT IN THE WAKE OF THE SURFACE LOW THAT WILL CONTINUE TO
STRENGTHEN TONIGHT AS IT MOVES NORTHEAST ACROSS MICHIGAN AND WILL
CONTINUE WIND ADVISORY THROUGH 3Z. MAY HAVE TO EXTEND AS GUSTS MAY
NOT BE DONE BY THEN BUT WILL REEVALUATE THIS ONCE TORNADO WATCHES
DROP TO AVOID ANY CONFUSION.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
STRONG COLD UPPER TROUGH WILL BE OVER THE AREA FOR SATURDAY THROUGH
SUNDAY. 850 MB TEMPERATURES DROP TO -10 TO -12 C FOR MUCH OF THE
SHORT TERM...AND WITH STRENGTH OF SYSTEM MOVING THROUGH CURRENTLY
THINK THIS IS LEGITIMATE. THEREFORE WILL STICK TO COLD END OF
GUIDANCE OR GO A COUPLE DEGREES COOLER AT TIMES. WITH LITTLE SHORT
WAVES MOVING THROUGH THE UPPER TROUGH IN THE NORTH WILL ADD A SLIGHT
CHANCE FOR SNOW ACROSS THE NORTHERN COUNTIES FOR SATURDAY AND
FLURRIES FOR LATE SATURDAY NIGHT. FOR SUNDAY WILL CONTINUE TO CARRY
CHANCE POPS BUT WITH TEMPERATURES LOOKING COLDER WILL SEE SNOW
ACROSS THE NORTH...A MIX CENTRAL AND CHANGEOVER TO ALL RAIN ONLY IN
THE SOUTH. LOOKS LIKE THE BACK END OF THE TROUGH WILL MOVE THROUGH
SUNDAY NIGHT SO WILL INCLUDE A SLIGHT CHANCE OF SNOW THEN.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
ACCEPTED CR INITIALIZATION AS IS DUE TO SEVERE WEATHER. ABOVE NORMAL
TEMPERATURES AND CHANCES FOR RAIN WITH A SYSTEM FROM MID WEEK ON.
&&
.AVIATION /DISCUSSION FOR 022200Z TAF UPDATE/...
REMOVED ALL CBS AND ANY MENTION OF THUNDER FROM SITES AS ALL IS EAST
OF THE TERMINALS. ADDED LOW MVFR CLOUD DECK MOVING IN OVER THE NEXT
COUPLE OF HOURS BASED ON SATELLITE LOOP AND ALSO BROUGHT STRONGER
WINDS IN FASTER BASED ON UPSTREAM OBSERVATIONS.
18Z DISCUSSION FOLLOWS...
RAPIDLY DETERIORATING CONDITIONS WITHIN SEVERE CONVECTION WILL
IMPACT ALL TERMINALS THIS AFTERNOON. MAINLY VFR OVERNIGHT INTO
SATURDAY MORNING.
WARM FRONT CURRENTLY PROGRESSING NORTH THROUGH THE FORECAST AREA
LATE THIS MORNING WITH CONVECTION ALONG AND NORTH OF THE BOUNDARY.
AS OF 1630Z...KLAF IS THE ONLY TERMINAL BEING DIRECTLY IMPACTED BY
THIS CONVECTION. HRRR HAS A NICE HANDLE ON CURRENT ACTIVITY...WITH
EXPECTATION THAT CONVECTION ACROSS NORTHERN COUNTIES MOVES OUT OF
THE FORECAST AREA BY 18-19Z. FOCUS THOUGH ALREADY SHIFTING TO
ALONG THE COLD FRONT OVER SOUTHEAST MISSOURI WHERE SEVERE
CONVECTION IS ALREADY RAPIDLY DEVELOPING. THIS ACTIVITY WILL
QUICKLY SPREAD NORTHEAST WITH ADDITIONAL CONVECTION LIKELY
DEVELOPING OUT IN FRONT OF THE MAIN LINE. AFTER A PERIOD WITH
FILTERED SUNSHINE EARLY THIS AFTERNOON...EXPECT IMPACTS FROM
CONVECTION AT ALL TERMINALS AFTER 19Z AND CONTINUING THROUGH 00Z.
STORMS WILL BE FAST MOVERS...CAPABLE OF PRODUCING SEVERE WIND
GUSTS AND CAUSING CONDITIONS AT THE TERMINALS TO DROP RAPIDLY TO
VLIFR AT TIMES. OUTSIDE OF CONVECTION...THE INTENSIFYING NATURE OF
THE LOW PRESSURE WILL CREATE STRONG WIND GUSTS UP TO 35-40KTS INTO
THE EARLY EVENING. WILL UPDATE TAFS AS NEEDED THROUGH THE AFTERNOON.
STORMS WILL BE EAST OF THE AREA AFTER 00Z WITH SKIES BECOMING
PARTLY CLOUDY AS MUCH DRIER AIR FILTERS INTO THE AREA. WIND GUSTS
WILL STAY UP THROUGH THE EVENING...EVENTUALLY DROPPING OFF TO
20-25KT OVERNIGHT AS WINDS VEER TO A MORE WESTERLY DIRECTION.
STRATOCU WILL REDEVELOP AND EXPAND BACK INTO THE TERMINALS
SATURDAY MORNING AS REGION GETS INTO CYCLONIC FLOW ON BACK SIDE OF
THE LOW PRESSURE. MAY SEE MVFR CEILINGS DEVELOP AT BOTH KHUF AND
KLAF. WESTERLY WIND GUSTS TO 25KTS WILL CONTINUE AS WELL.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 10 PM EST THIS EVENING FOR INZ021-028>031-
035>049-051>057-060>065-067>072.
&&
$$
SYNOPSIS...CP
NEAR TERM...CP
SHORT TERM...CP
LONG TERM....CP
AVIATION...RYAN/CP
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
329 PM EST FRI MAR 2 2012
.UPDATE...
THE SYNOPSIS...NEAR TERM...SHORT TERM AND LONG TERM SECTIONS HAVE
BEEN UPDATED BELOW.
&&
.SYNOPSIS...A STRONG LOW PRESSURE SYSTEM WILL KEEP STORMS IN THE AREA FOR THE
NEXT FEW HOURS...THEN STRONG WINDS SHOULD REMAIN IN ITS WAKE INTO
THE NIGHT. THIS WILL USHER IN MUCH COLDER AIR FOR THE WEEKEND BEFORE
UPPER RIDGING BRINGS WARMER AIR AND ANOTHER SYSTEM MOVES IN WITH
CHANCES FOR RAIN MID WEEK.
&&
.NEAR TERM /THIS AFTERNOON THROUGH TONIGHT/...
SEVERE THREAT CONTINUES. THUNDERSTORMS...SOME SEVERE...ONGOING
ACROSS MUCH OF THE FORECAST AREA. THE COLD FRONT LAGS THESE BY QUITE
A BIT AND THERE IS CLEARING IN THE MIDDLE WHERE RAPID REFRESH IS
SHOWING SOME REDEVELOPMENT SO MAY NOT BE ABLE TO CLEAR OUT RISK
UNTIL A BIT LATER. STILL LOOKS LIKE EVERYTHING WILL BE OUT OF THE
AREA BY 0Z BUT WILL CONTINUE TO CARRY A CHANCE IN THE EAST SINCE
TORNADO WATCH THERE RUNS UNTIL 2Z BUT EXPECT TO BE ABLE TO CANCEL
THAT EARLY. WINDS WILL PICK UP BEHIND THE FRONT WITH TIGHT PRESSURE
GRADIENT IN THE WAKE OF THE SURFACE LOW THAT WILL CONTINUE TO
STRENGTHEN TONIGHT AS IT MOVES NORTHEAST ACROSS MICHIGAN AND WILL
CONTINUE WIND ADVISORY THROUGH 3Z. MAY HAVE TO EXTEND AS GUSTS MAY
NOT BE DONE BY THEN BUT WILL REEVALUATE THIS ONCE TORNADO WATCHES
DROP TO AVOID ANY CONFUSION.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
STRONG COLD UPPER TROUGH WILL BE OVER THE AREA FOR SATURDAY THROUGH
SUNDAY. 850 MB TEMPERATURES DROP TO -10 TO -12 C FOR MUCH OF THE
SHORT TERM...AND WITH STRENGTH OF SYSTEM MOVING THROUGH CURRENTLY
THINK THIS IS LEGITIMATE. THEREFORE WILL STICK TO COLD END OF
GUIDANCE OR GO A COUPLE DEGREES COOLER AT TIMES. WITH LITTLE SHORT
WAVES MOVING THROUGH THE UPPER TROUGH IN THE NORTH WILL ADD A SLIGHT
CHANCE FOR SNOW ACROSS THE NORTHERN COUNTIES FOR SATURDAY AND
FLURRIES FOR LATE SATURDAY NIGHT. FOR SUNDAY WILL CONTINUE TO CARRY
CHANCE POPS BUT WITH TEMPERATURES LOOKING COLDER WILL SEE SNOW
ACROSS THE NORTH...A MIX CENTRAL AND CHANGEOVER TO ALL RAIN ONLY IN
THE SOUTH. LOOKS LIKE THE BACK END OF THE TROUGH WILL MOVE THROUGH
SUNDAY NIGHT SO WILL INCLUDE A SLIGHT CHANCE OF SNOW THEN.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
ACCEPTED CR INITIALIZATION AS IS DUE TO SEVERE WEATHER. ABOVE NORMAL
TEMPERATURES AND CHANCES FOR RAIN WITH A SYSTEM FROM MID WEEK ON.
&&
.AVIATION /DISCUSSION FOR 022100Z TAF UPDATE/...
CONVECTION HAS MOVED EAST OF THE TERMINALS AS OF 2030Z. COLD FRONT
REMAINS OVER EASTERN ILLINOIS AND A WELL DEFINED CLEAR SLOT
PROGRESSING EAST IN FRONT OF IT. HAVE REMOVED TEMPO GROUPS FOR
CONVECTION AT ALL BUT KBMG BUT HAVE LEFT VCTS IN FOR THE NEXT FEW
HOURS TO ACCOUNT FOR ANY REDEVELOPMENT AHEAD OF THE FRONT.
READJUSTED CEILINGS AND WINDS AS WELL.
18Z DISCUSSION FOLLOWS.
RAPIDLY DETERIORATING CONDITIONS WITHIN SEVERE CONVECTION WILL
IMPACT ALL TERMINALS THIS AFTERNOON. MAINLY VFR OVERNIGHT INTO
SATURDAY MORNING.
WARM FRONT CURRENTLY PROGRESSING NORTH THROUGH THE FORECAST AREA
LATE THIS MORNING WITH CONVECTION ALONG AND NORTH OF THE BOUNDARY.
AS OF 1630Z...KLAF IS THE ONLY TERMINAL BEING DIRECTLY IMPACTED BY
THIS CONVECTION. HRRR HAS A NICE HANDLE ON CURRENT ACTIVITY...WITH
EXPECTATION THAT CONVECTION ACROSS NORTHERN COUNTIES MOVES OUT OF
THE FORECAST AREA BY 18-19Z. FOCUS THOUGH ALREADY SHIFTING TO
ALONG THE COLD FRONT OVER SOUTHEAST MISSOURI WHERE SEVERE
CONVECTION IS ALREADY RAPIDLY DEVELOPING. THIS ACTIVITY WILL
QUICKLY SPREAD NORTHEAST WITH ADDITIONAL CONVECTION LIKELY
DEVELOPING OUT IN FRONT OF THE MAIN LINE. AFTER A PERIOD WITH
FILTERED SUNSHINE EARLY THIS AFTERNOON...EXPECT IMPACTS FROM
CONVECTION AT ALL TERMINALS AFTER 19Z AND CONTINUING THROUGH 00Z.
STORMS WILL BE FAST MOVERS...CAPABLE OF PRODUCING SEVERE WIND
GUSTS AND CAUSING CONDITIONS AT THE TERMINALS TO DROP RAPIDLY TO
VLIFR AT TIMES. OUTSIDE OF CONVECTION...THE INTENSIFYING NATURE OF
THE LOW PRESSURE WILL CREATE STRONG WIND GUSTS UP TO 35-40KTS INTO
THE EARLY EVENING. WILL UPDATE TAFS AS NEEDED THROUGH THE AFTERNOON.
STORMS WILL BE EAST OF THE AREA AFTER 00Z WITH SKIES BECOMING
PARTLY CLOUDY AS MUCH DRIER AIR FILTERS INTO THE AREA. WIND GUSTS
WILL STAY UP THROUGH THE EVENING...EVENTUALLY DROPPING OFF TO
20-25KT OVERNIGHT AS WINDS VEER TO A MORE WESTERLY DIRECTION.
STRATOCU WILL REDEVELOP AND EXPAND BACK INTO THE TERMINALS
SATURDAY MORNING AS REGION GETS INTO CYCLONIC FLOW ON BACK SIDE OF
THE LOW PRESSURE. MAY SEE MVFR CEILINGS DEVELOP AT BOTH KHUF AND
KLAF. WESTERLY WIND GUSTS TO 25KTS WILL CONTINUE AS WELL.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 10 PM EST THIS EVENING FOR INZ021-028>031-
035>049-051>057-060>065-067>072.
&&
$$
SYNOPSIS...CP
NEAR TERM...CP
SHORT TERM...CP
LONG TERM....CP
AVIATION...RYAN
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
307 PM EST FRI MAR 2 2012
.UPDATE...
THE SYNOPSIS...NEAR TERM...SHORT TERM
AND LONG TERM SECTIONS HAVE BEEN UPDATED BELOW.
&&
.SYNOPSIS...A STRONG LOW PRESSURE SYSTEM WILL KEEP STORMS IN THE AREA FOR THE
NEXT FEW HOURS...THEN STRONG WINDS SHOULD REMAIN IN ITS WAKE INTO
THE NIGHT. THIS WILL USHER IN MUCH COLDER AIR FOR THE WEEKEND BEFORE
UPPER RIDGING BRINGS WARMER AIR AND ANOTHER SYSTEM MOVES IN WITH
CHANCES FOR RAIN MID WEEK.
&&
.NEAR TERM /THIS AFTERNOON THROUGH TONIGHT/...
SEVERE THREAT CONTINUES. THUNDERSTORMS...SOME SEVERE...ONGOING
ACROSS MUCH OF THE FORECAST AREA. THE COLD FRONT LAGS THESE BY QUITE
A BIT AND THERE IS CLEARING IN THE MIDDLE WHERE RAPID REFRESH IS
SHOWING SOME REDEVELOPMENT SO MAY NOT BE ABLE TO CLEAR OUT RISK
UNTIL A BIT LATER. STILL LOOKS LIKE EVERYTHING WILL BE OUT OF THE
AREA BY 0Z BUT WILL CONTINUE TO CARRY A CHANCE IN THE EAST SINCE
TORNADO WATCH THERE RUNS UNTIL 2Z BUT EXPECT TO BE ABLE TO CANCEL
THAT EARLY. WINDS WILL PICK UP BEHIND THE FRONT WITH TIGHT PRESSURE
GRADIENT IN THE WAKE OF THE SURFACE LOW THAT WILL CONTINUE TO
STRENGTHEN TONIGHT AS IT MOVES NORTHEAST ACROSS MICHIGAN AND WILL
CONTINUE WIND ADVISORY THROUGH 3Z. MAY HAVE TO EXTEND AS GUSTS MAY
NOT BE DONE BY THEN BUT WILL REEVALUATE THIS ONCE TORNADO WATCHES
DROP TO AVOID ANY CONFUSION.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
STRONG COLD UPPER TROUGH WILL BE OVER THE AREA FOR SATURDAY THROUGH
SUNDAY. 850 MB TEMPERATURES DROP TO -10 TO -12 C FOR MUCH OF THE
SHORT TERM...AND WITH STRENGTH OF SYSTEM MOVING THROUGH CURRENTLY
THINK THIS IS LEGITIMATE. THEREFORE WILL STICK TO COLD END OF
GUIDANCE OR GO A COUPLE DEGREES COOLER AT TIMES. WITH LITTLE SHORT
WAVES MOVING THROUGH THE UPPER TROUGH IN THE NORTH WILL ADD A SLIGHT
CHANCE FOR SNOW ACROSS THE NORTHERN COUNTIES FOR SATURDAY AND
FLURRIES FOR LATE SATURDAY NIGHT. FOR SUNDAY WILL CONTINUE TO CARRY
CHANCE POPS BUT WITH TEMPERATURES LOOKING COLDER WILL SEE SNOW
ACROSS THE NORTH...A MIX CENTRAL AND CHANGEOVER TO ALL RAIN ONLY IN
THE SOUTH. LOOKS LIKE THE BACK END OF THE TROUGH WILL MOVE THROUGH
SUNDAY NIGHT SO WILL INCLUDE A SLIGHT CHANCE OF SNOW THEN.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
ACCEPTED CR INITIALIZATION AS IS DUE TO SEVERE WEATHER. ABOVE NORMAL
TEMPERATURES AND CHANCES FOR RAIN WITH A SYSTEM FROM MID WEEK ON.
&&
.AVIATION /DISCUSSION FOR 021800Z TAF ISSUANCE/...
RAPIDLY DETERIORATING CONDITIONS WITHIN SEVERE CONVECTION WILL
IMPACT ALL TERMINALS THIS AFTERNOON. MAINLY VFR OVERNIGHT INTO
SATURDAY MORNING.
WARM FRONT CURRENTLY PROGRESSING NORTH THROUGH THE FORECAST AREA
LATE THIS MORNING WITH CONVECTION ALONG AND NORTH OF THE BOUNDARY.
AS OF 1630Z...KLAF IS THE ONLY TERMINAL BEING DIRECTLY IMPACTED BY
THIS CONVECTION. HRRR HAS A NICE HANDLE ON CURRENT ACTIVITY...WITH
EXPECTATION THAT CONVECTION ACROSS NORTHERN COUNTIES MOVES OUT OF
THE FORECAST AREA BY 18-19Z. FOCUS THOUGH ALREADY SHIFTING TO
ALONG THE COLD FRONT OVER SOUTHEAST MISSOURI WHERE SEVERE
CONVECTION IS ALREADY RAPIDLY DEVELOPING. THIS ACTIVITY WILL
QUICKLY SPREAD NORTHEAST WITH ADDITIONAL CONVECTION LIKELY
DEVELOPING OUT IN FRONT OF THE MAIN LINE. AFTER A PERIOD WITH
FILTERED SUNSHINE EARLY THIS AFTERNOON...EXPECT IMPACTS FROM
CONVECTION AT ALL TERMINALS AFTER 19Z AND CONTINUING THROUGH 00Z.
STORMS WILL BE FAST MOVERS...CAPABLE OF PRODUCING SEVERE WIND
GUSTS AND CAUSING CONDITIONS AT THE TERMINALS TO DROP RAPIDLY TO
VLIFR AT TIMES. OUTSIDE OF CONVECTION...THE INTENSIFYING NATURE OF
THE LOW PRESSURE WILL CREATE STRONG WIND GUSTS UP TO 35-40KTS INTO
THE EARLY EVENING. WILL UPDATE TAFS AS NEEDED THROUGH THE AFTERNOON.
STORMS WILL BE EAST OF THE AREA AFTER 00Z WITH SKIES BECOMING
PARTLY CLOUDY AS MUCH DRIER AIR FILTERS INTO THE AREA. WIND GUSTS
WILL STAY UP THROUGH THE EVENING...EVENTUALLY DROPPING OFF TO
20-25KT OVERNIGHT AS WINDS VEER TO A MORE WESTERLY DIRECTION.
STRATOCU WILL REDEVELOP AND EXPAND BACK INTO THE TERMINALS
SATURDAY MORNING AS REGION GETS INTO CYCLNIC FLOW ON BACK SIDE OF
THE LOW PRESSURE. MAY SEE MVFR CEILINGS DEVELOP AT BOTH KHUF AND
KLAF. WESTERLY WIND GUSTS TO 25KTS WILL CONTINUE AS WELL.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 10 PM EST THIS EVENING FOR INZ021-028>031-
035>049-051>057-060>065-067>072.
&&
$$
SYNOPSIS...CP
NEAR TERM...CP
SHORT TERM...CP
LONG TERM....CP
AVIATION...RYAN
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1154 AM EST FRI MAR 2 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
A STRONG LOW PRESSURE SYSTEM WILL MOVE INTO LOWER MICHIGAN
TODAY...BRINGING SEVERE WEATHER TO THE OHIO VALLEY TODAY ALONG WITH
GUSTY WINDS OUTSIDE OF THUNDERSTORMS. MUCH COLDER AIR WILL THEN MOVE
IN FOR THE WEEKEND...WITH A WEAK SYSTEM BRINGING A CHANCE FOR RAIN
AND SNOW SUNDAY.
WARMER WEATHER WILL RETURN DURING NEXT WEEK...WITH CHANCES FOR RAIN
RETURNING BY THE END OF NEXT WEEK.
&&
.NEAR TERM /REST OF TODAY/... ONGOING STORMS ACROSS THE AREA AT
15Z...SOME OF WHICH ARE PRODUCING LARGE HAIL. THE WARM
FRONT...WHICH AT 15Z STRETCHED FROM SULLIVAN TO BLOOMINGTON TO
SEYMOUR...WILL CONTINUE TO LIFT NORTHWARD AND DEW POINTS BEHIND
THE FRONT ARE INCREASING TO THE MID 50S TO LOW 60S CURRENTLY
ACROSS SOUTHERN INDIANA WITH TEMPERATURES IN THE LOW TO MID 60S
AND THIS AIR WILL BE ADVECTING NORTH INTO THE AREA. WITH THIS
UNSTABLE AIR AND THE DYNAMIC STRENGTHENING LOW CENTERED OVER ST
LOUIS AT 15Z PROGGED TO MOVE JUST NORTHWEST OF THE AREA AND DRAG A
COLD FRONT THROUGH CENTRAL INDIANA BETWEEN 20Z IN THE WEST AND 0Z
IN THE EAST. SURFACE BASED CAPE COULD CLIMB TO NEAR 1000 AND NEAR
2000 ACROSS THE SOUTH...AND 0-1 KM HELICITY AND 0-3 KM HELICITY
VALUES ARE PROGGED TO BE IN THE 300 /FOR 0 TO 1/ AND 500 /FOR 0 TO
3/ RANGE IN THE WARM SECTOR AND AHEAD OF/ALONG THE COLD FRONT.
THUS THE THREAT FOR SEVERE WEATHER WILL GET EVEN MORE SIGNIFICANT
THIS AFTERNOON WITH THE THREAT FOR TORNADOES...LARGE HAIL OF 2
INCHES IN DIAMETER OR MORE...AND DAMAGING WINDS IN EXCESS OF 65
MPH BEING LIKELY IN SOME STORMS. THIS IS A DANGEROUS SITUATION AND
SHOULD NOT BE TAKEN LIGHTLY.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
FOCUS IS ON WIND/RAIN EARLY THEN ON CHANCES FOR PRECIPITATION LATE
IN THE PERIOD. MODELS ARE IN GOOD AGREEMENT EARLY BUT DIFFER SOME
WITH SUNDAY/S SYSTEM. TOOK A BLEND THERE AS UNCERTAINTY IS HIGH
ENOUGH NOT TO FAVOR ONE SOLUTION OVER ANOTHER.
THE STRONG PRESSURE RISES /OVER 10MB IN 6 HOURS/ WILL OCCUR INTO THE
EVENING HOURS. BUFKIT STILL SHOWS GUSTS 35-40KT EARLY. THUS WILL
CONTINUE THE WIND ADVISORY UNTIL 03Z.
PRECIPITATION SHOULD END QUICKLY BEHIND THE FRONT...AND WRAP-AROUND
MOISTURE SHOULD STAY MAINLY NORTH OF THE AREA. THUS FEEL CHANCES FOR
RAIN AFTER 00Z ARE LOW. MOS POPS ARE BELOW 20 PERCENT. WILL CARRY
LOW POPS FOR A FEW HOURS THIS EVENING JUST IN CASE SOMETHING
LINGERS...BUT BELIEVE MOST AREAS WILL REMAIN DRY AFTER 00Z.
DRY AND PARTLY TO MOSTLY CLOUDY CONDITIONS WILL THEN PERSIST FOR
SATURDAY AND SATURDAY NIGHT. A WEAK CLIPPER-LIKE SYSTEM WILL DIVE
SOUTHEAST IN THE SUNDAY-SUNDAY NIGHT TIME FRAME. WITH UNCERTAINTIES
IN LOCATION AND TIMING DECIDED JUST TO GO WITH LOW POPS BOTH
PERIODS. WENT RAIN AND SNOW MOST AREAS SUNDAY AND THEN JUST SNOW
SUNDAY NIGHT GIVEN EXPECTED THERMAL PROFILES.
FOR TEMPERATURES...GENERALLY STUCK WITH A MODEL BLEND AS THIS WORKS
WELL GIVEN EXPECTED CONDITIONS.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
MAIN CHALLENGE TO THE EXTENDED WILL BE WHETHER TO KEEP POPS IN
MONDAY AS AN UPPER TROUGH MOVES EAST OF CENTRAL INDIANA AND ALSO
POPS AND QPF STARTING WEDNESDAY NIGHT.
DECIDED TO PULL SLIGHT CHANCE POPS ON MONDAY PER THE CENTRAL
REGIONAL INITIALIZATION EXTENDED AS ALL THE EXTENDED 00Z MODEL RUNS
NOW HAVE THE TROUGH WELL EAST OF CENTRAL INDIANA ACROSS THE ATLANTIC
SEABOARD BY 00Z TUESDAY WITH RIDGING BUILDING IN ACROSS THE GREAT
LAKES AND OHIO VALLEY. IN ADDITION...THE FORECAST AREA WILL BE UNDER
THE INFLUENCE OF SURFACE HIGH PRESSURE AND MOISTURE IS NOT
IMPRESSIVE.
THE MIDDLE OF THE WEEK CONTINUES TO LOOK DRY WITH FAST SOUTHWEST
FLOW DEVELOPING. IN ADDITION...IT SHOULD BE WARMER EACH DAY WITH
THERMAL RIDGE EXTENDING NORTHEAST FROM TEXAS TO THE OHIO VALLEY AND
GREAT LAKES BY WEDNESDAY. 1000-850 MILLIBAR THICKNESSES AND
850 TEMPERATURES APPROACH 1350 METERS AND 6 DEGREES CELSIUS
RESPECTIVELY ON WEDNESDAY. THE CR INITIALIZATION REFLECTS THIS
NICELY WITH BELOW NORMAL TEMPERATURES ON MONDAY BECOMING MILD
ALREADY BY TUESDAY.
FINALLY...THE 00Z ECMWF IS NOW TRENDING TOWARDS THE GFS AND GFS
ENSEMBLES WITH A CUTOFF LOW ACROSS THE SOUTHWESTERN UNITED STATES BY
MIDWEEK...MOVING INTO WEST TEXAS ON THURSDAY. HOWEVER...THE ECMWF IS
A BIT FURTHER SOUTH AND CONTINUES TO ALLOW A SHARP UPPER TROUGH TO
MOVE ACROSS THE UPPER MIDWEST AND GREAT LAKES OVER THE WEEKEND AND
CONSEQUENTLY PUSHES A COLD FRONT THROUGH ON THURSDAY...WHILE THE GFS
ONLY HAS AN INVERTED TROUGH WELL WEST OF THE FORECAST AREA AT THAT
TIME. EITHER WAY...MODELS HAVE QPF ACROSS PARTS OR ALL OF CENTRAL
INDIANA WEDNESDAY NIGHT THROUGH FRIDAY. HOWEVER...THE QUICKER AND
STRONGER SURFACE REFLECTION OF THE EURO FAVORS MORE QPF. AT THIS
TIME...DID NOT CHANGE ANYTHING BEYOND MONDAY FROM THE INITIALIZATION
DUE TO BIG MODEL SYNOPTIC DIFFERENCES WHICH LEADS TO LOW CONFIDENCE
NOT ONLY WITH POPS AND QPF BUT ALSO WITH TEMPERATURES ON FRIDAY...
AS THE ECMWF IS BRINGING IN COLDER POST FRONTAL AIR...WHILE THE
GFS...AS STATED EARLIER...IS SLOWER AND NOT AS STRONG WITH THE
SURFACE PATTERN.
&&
.AVIATION /DISCUSSION FOR 021800Z TAF ISSUANCE/...
RAPIDLY DETERIORATING CONDITIONS WITHIN SEVERE CONVECTION WILL
IMPACT ALL TERMINALS THIS AFTERNOON. MAINLY VFR OVERNIGHT INTO
SATURDAY MORNING.
WARM FRONT CURRENTLY PROGRESSING NORTH THROUGH THE FORECAST AREA
LATE THIS MORNING WITH CONVECTION ALONG AND NORTH OF THE BOUNDARY.
AS OF 1630Z...KLAF IS THE ONLY TERMINAL BEING DIRECTLY IMPACTED BY
THIS CONVECTION. HRRR HAS A NICE HANDLE ON CURRENT ACTIVITY...WITH
EXPECTATION THAT CONVECTION ACROSS NORTHERN COUNTIES MOVES OUT OF
THE FORECAST AREA BY 18-19Z. FOCUS THOUGH ALREADY SHIFTING TO
ALONG THE COLD FRONT OVER SOUTHEAST MISSOURI WHERE SEVERE
CONVECTION IS ALREADY RAPIDLY DEVELOPING. THIS ACTIVITY WILL
QUICKLY SPREAD NORTHEAST WITH ADDITIONAL CONVECTION LIKELY
DEVELOPING OUT IN FRONT OF THE MAIN LINE. AFTER A PERIOD WITH
FILTERED SUNSHINE EARLY THIS AFTERNOON...EXPECT IMPACTS FROM
CONVECTION AT ALL TERMINALS AFTER 19Z AND CONTINUING THROUGH 00Z.
STORMS WILL BE FAST MOVERS...CAPABLE OF PRODUCING SEVERE WIND
GUSTS AND CAUSING CONDITIONS AT THE TERMINALS TO DROP RAPIDLY TO
VLIFR AT TIMES. OUTSIDE OF CONVECTION...THE INTENSIFYING NATURE OF
THE LOW PRESSURE WILL CREATE STRONG WIND GUSTS UP TO 35-40KTS INTO
THE EARLY EVENING. WILL UPDATE TAFS AS NEEDED THROUGH THE AFTERNOON.
STORMS WILL BE EAST OF THE AREA AFTER 00Z WITH SKIES BECOMING
PARTLY CLOUDY AS MUCH DRIER AIR FILTERS INTO THE AREA. WIND GUSTS
WILL STAY UP THROUGH THE EVENING...EVENTUALLY DROPPING OFF TO
20-25KT OVERNIGHT AS WINDS VEER TO A MORE WESTERLY DIRECTION.
STRATOCU WILL REDEVELOP AND EXPAND BACK INTO THE TERMINALS
SATURDAY MORNING AS REGION GETS INTO CYCLNIC FLOW ON BACK SIDE OF
THE LOW PRESSURE. MAY SEE MVFR CEILINGS DEVELOP AT BOTH KHUF AND
KLAF. WESTERLY WIND GUSTS TO 25KTS WILL CONTINUE AS WELL.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM 4 PM THIS AFTERNOON TO 10 PM EST THIS EVENING
FOR INZ021-028>031-035>049-051>057-060>065-067>072.
&&
$$
SYNOPSIS...50
NEAR TERM...CP
SHORT TERM...50
LONG TERM....MK
AVIATION...RYAN
AREA FORECAST DISCUSSION
NWS JACKSON KY
129 PM EST FRI MAR 2 2012
.UPDATE...
ISSUED AT 129 PM EST FRI MAR 2 2012
OUTSIDE OF THE EARLY SEVERE WEATHER ACROSS OUR SOUTHEAST AREAS...IT
NOW LOOKS LIKE THE AREA WILL BE LOCATED SOLIDLY IN THE WARM SECTOR
THROUGH THIS EVENING. HAVE REMOVED POPS FOR MOST AREAS OVER THE NEXT
SEVERAL HOURS...UNTIL ADDITIONAL DEVELOPMENT SPREADS INTO THE AREA
LATER THIS EVENING. WITH THE FAVORABLE CONDITIONS IN PLACE...SPC HAS
ISSUED A TORNADO WARNING FOR OUR FAR WESTERN AND NORTHERN COUNTIES
UNTIL 9 PM. IT APPEARS THE THREAT WILL HOLD OFF UNTIL THE TAIL END OF
THE WATCH...LIKELY NOT REACHING OUR AREA UNTIL AT LEAST 5 OR 6 PM.
ALL IN ALL...FORECAST LOOKS IN GOOD SHAPE.
UPDATE ISSUED AT 1234 PM EST FRI MAR 2 2012
DRY SLOT IS NOT NOSING INTO OUR SOUTHWEST COUNTIES...ENDING
PRECIPITATION THERE TEMPORARILY. THE SHOWERS AND STORMS SHOULD
CONTINUE TO DEPART TO THE NORTH AND EAST EARLY THIS
AFTERNOON...LEAVING MOST OF EASTERN KENTUCKY DRY FROM MID TO LATE
AFTERNOON. THIS WILL ALLOW TEMPERATURES TO WARM INTO THE MID 70S WITH
SOME BROKEN CIGS SPREADING ACROSS THE AREA. WITH DECENT MIXING
POTENTIAL...WE SHOULD SEE STRONG WINDS MIXING DOWN WITH SOME GUSTS UP
TO 40 MPH LIKELY. CANNOT RULE OUT AN ISOLATED STORM THIS
AFTERNOON...BUT THE MORE LIKELY SCENARIO IS ACTIVITY ARRIVING AHEAD
OF THE FRONTAL BOUNDARY LATER THIS EVENING.
MEANWHILE...SHOWERS AND STORMS ARE ALREADY DEVELOPING ALONG AND JUST
AHEAD OF THE FRONTAL BOUNDARY ACROSS MISSOURI AND ILLINOIS. BASED ON
LATEST HRRR...THIS ACTIVITY SHOULD PUSH INTO OUR BLUEGRASS COUNTIES
TOWARDS 5 OR 6 PM...THEN ACROSS THE REST OF EASTERN KENTUCKY THROUGH
10 PM. EARLY ON...STILL CONCERNED WITH DISCRETE SUPERCELLS...CAPABLE
OF DAMAGING WINDS...LARGE HAIL...AND A TORNADO. AS THE FRONT PUSHES
INTO THE REGION...A SQUALL LINE WILL LIKELY EVOLVE...WITH THE MAIN
THREAT STRAIGHT LINE DAMAGING WINDS. HOWEVER...A SPIN UP TORNADO
ALONG THE LINE IS POSSIBLE STILL. WITH THE FAST MOVEMENT OF
STORMS...THE SEVERE THREAT MAY BE OVER FOR MOST OF THE AREA BY
MIDNIGHT...WITH JUST SOME LEFT OVER RAIN PUSHING ACROSS OUR EASTERN
COUNTIES. HAVE LOWERED TEMPERATURES BEHIND THE FRONT TONIGHT...WITH
DECENT CLEARING SPREADING INTO THE AREA.
UPDATE ISSUED AT 1129 AM EST FRI MAR 2 2012
WIDESPREAD SHOWERS AND STORMS CONTINUE TO PROGRESS NORTHWARD ACROSS
THE CWA THIS MORNING...BUT A DISTINCT BACK EDGE AND DRY SLOT...BEHIND
THE ADVANCING WARM FRONT IS NOTED BACK ACROSS CENTRAL TENNESSEE.
USING THE TIMING TOOL...IT LOOKS LIKE THE ONGOING ACTIVITY SHOULD
PUSH NORTH AND EAST OF THE AREA BY 19Z...PROVIDING A DECENT BREAK FOR
MOST AREAS THIS AFTERNOON. HRRR IS HANDLING THE SITUATION FAIRLY
WELL. IT SHOWS SOME DISTINCT SUPERCELLS DEVELOPING OUT IN THE
BLUEGRASS BETWEEN 21 AND 22Z. THESE MAY IMPACT OUR NORTHEAST BLUEGRASS
COUNTIES AROUND THIS TIME. THESE STORMS WOULD OBVIOUSLY HAVE THE
POTENTIAL FOR LARGE HAIL...DAMAGING WINDS...AND TORNADOES. THESE
STORMS SHOULD DEVELOP OUT AHEAD OF THE ADVANCING COLD FRONT...WITH A
SQUALL LINE DEVELOPING ALONG THE ACTUAL FRONTAL BOUNDARY. THE MAIN
THREAT WITH THE SQUALL LINE WILL BE DAMAGING WINDS...BUT A BRIEF SPIN
UP ALONG THIS LINE IS POSSIBLE...PRODUCING A TORNADO. THE FRONTAL
BOUNDARY SHOULD HOLD OFF TO OUR WEST UNTIL AT LEAST 00Z. SO THE MAIN
THREAT PRIOR TO THAT TIME WILL BE THE DISCRETE SUPERCELLS IN THE WARM
SECTOR. WARM AND MUGGY CONDITIONS WILL DEVELOP HEADING INTO THIS
AFTERNOON WITH DEWPOINTS CLIMBING UP TO AROUND 60 WITH TEMPERATURES
AROUND 70. CERTAINLY JUICY AIR FOR THIS TIME OF YEAR. LAKE WIND
ADVISORY WILL CONTINUE AS ADVERTISED. FLASH FLOOD THREAT ALSO APPEARS
A BIT ENHANCED WITH EARLY DAY RAINFALL ADDING TO THE ALREADY SOAKED
GROUND AND BANK FULL CREEKS.
UPDATE ISSUED AT 837 AM EST FRI MAR 2 2012
SHOWERS AND THUNDERSTORMS HAVE BECOME MORE WIDESPREAD ACROSS THE AREA
OVER THE PAST HOUR. THUS...HAVE BROUGHT IN SOME HIGHER CATEGORICAL
POPS THROUGH THIS MORNING. ANOTHER BAND OF SHOWERS AND STORMS IS
KNOCKING AT OUR DOORSTEP...JUST NOW PUSHING INTO AREAS AROUND
MONTICELLO. AFTER THE MORNING CONVECTION...STILL LOOKING LIKE A
POTENTIAL BREAK BY MID AFTERNOON...BEFORE THE MAIN LINE OF CONVECTION
ARRIVES WITH THE FRONT BETWEEN 6 AND 9 PM. HAD SOME REPORTS OF
SUB-SEVERE HAIL THIS MORNING (HAIL LESS THAN AN INCH IN
DIAMETER)...BUT NOTHING SEVERE AS OF YET. MADE SOME TWEAKS TO
TEMPERATURES AND DEWPOINTS AS TEMPERATURES START TO WARM FROM SOUTH
TO NORTH AS THE FRONT PROGRESSES NORTHWARD.
UPDATE ISSUED AT 705 AM EST FRI MAR 2 2012
THE FORECAST IN GENERAL REMAINS ON TARGET...THOUGH CONVECTION UP UNTIL
THIS POINT HAS NOT BEEN ALL THAT WIDESPREAD. HOWEVER...ADDITIONAL
STRONG TO POSSIBLY SEVERE CONVECTION CONTINUES TO GET GOING TO OUR
SW IN NORTHERN MIDDLE TN AND SOME OF THIS ACTIVITY SHOULD LIFT NORTH
INTO THE REGION THROUGH MID TO LATE MORNING. ACTIVITY THIS MORNING
IS EXPECTED TO BE LARGELY ELEVATED AND EITHER WITH ONGOING CONVECTION
APPROACHING FROM CENTRAL KY AND THE CONVECTION APPROACHING FROM
MIDDLE TN WILL HAVE THE POTENTIAL TO PRODUCE HAIL...AND PERHAPS SOME
STRONGER WIND GUSTS.
ONCE THE WARM FRONT PASSES DURING THE MID AFTERNOON...THERE IS NOT A
LOT OF CONVECTIVE TRIGGERS...BUT ANY OUTFLOWS OR CONVECTION UPSTREAM
THAT MOVES IN OR ANY BREAKS IN THE CLOUDS COULD BE THE FOCUS FOR
INITIATION. OTHER THAN THE QUESTION OF A TRIGGER DURING MID AFTERNOON
AND SOME HINT OF MID LEVEL CAPPING IN THE FORECAST SOUNDINGS...IF
ANYTHING WERE TO GET GOING IT COULD BECOME SEVERE AS SHEAR WILL BE
AMPLE. IF THIS WERE TO BE IN SUPERCELL FORM...DAMAGING WINDS...LARGE
HAIL...AN EVEN A TORNADO WOULD BE POSSIBLE. IT STILL APPEARS THAT THE
MOST ORGANIZED SEVERE CONVECTION SHOULD OCCUR DURING THE LATE
AFTERNOON INTO THE EVENING HOURS.
HOURLY GRIDS WERE FRESHENED UP BASED ON THE LATEST TRENDS...BUT THE
PREVIOUS ZFP WAS STILL HANDLING THE SITUATION AT THIS TIME.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 430 AM EST FRI MAR 2 2012
SFC LOW PRESSURE OVER NE OKLAHOMA CONTINUES TO DEVELOP THIS MORNING
WITH A SFC WARM FRONT EXTENDING EAST INTO THE TN VALLEY REGION. AT
PRESENT IT IS ABOUT 2 MB STRONGER THAN THE 6Z NAM RUNS AND SLIGHTLY
STRONGER THAN MOST OF THE 0Z MODEL RUNS. THIS SYSTEM IS PROGGED TO
FURTHER DEEPEN AS IT TRACKS INTO THE GREAT LAKES THIS EVENING...WITH
THE MOST RAPID DEEPENING OCCURRING BETWEEN 18Z AND 0Z TONIGHT. THIS
SYSTEM WILL SEND A STRONG COLD FRONT INTO THE COMMONWEALTH...WITH THE
COLD FRONT REACHING THE JKL CWA DURING THE EVENING. THE COLD FRONT
SHOULD EXIT INTO VA EARLY ON AT AM.
DESPITE RELATIVELY CLOUD FREE CONDITIONS AT PRESENT WITH SOME VALLEY
LOCATIONS AT PRESENT IN THE 30S...A RATHER DRAMATIC RISE IN TEMPS AND
DEWPOINTS IS ANTICIPATED TODAY AS THE WARM FRONT LIFTS INTO THE
REGION FROM THE SOUTH AND WEST...MOVING NORTH AND EAST OF THE JKL CWA
BY EARLY TO MID AFTERNOON. DEWPOINTS ACROSS THE CWA ARE CURRENTLY IN
THE UPPER 20S AND 30S...BUT JUST SOUTH OF THE AREA DEWPOINTS IN THE
MID 40S ARE PRESENT ACROSS NORTHERN MIDDLE TN...THE 50S TO THE SOUTH
OF THAT AREA MIDDLE AND EAST TN AND THEN FURTHER SOUTH IN MS AND
AL...DEWPOINTS ARE IN THE LOWER 60S.
MODELS ALL PROG A RAPID INCREASE IN MOISTURE THIS MORNING AS THE WARM
FRONT MOVES INTO AND ACROSS THE AREA...AS HAS BEEN OCCURRING TO OUR SOUTH
AND WEST OVERNIGHT. AN AREA OF SHOWERS AND THUNDERSTORMS CONTINUES
TO DEVELOP FROM WEST CENTRAL KY SE INTO THE CUMBERLAND PLATEAU OF
MIDDLE TN. THIS CONVECTION SHOULD CONTINUE TO DEVELOP EARLY THIS
MORNING AND BECOME MORE WIDESPREAD AS MOISTURE TRANSPORT INCREASES AS
THE LOW LEVEL JET INCREASES. A ROUND OF SHOWERS AND AT LEAST SCATTERED
THUNDERSTORMS SHOULD OCCUR THIS MORNING. INSTABILITY IS PROGGED TO BE
RATHER LIMITED AND THIS CONVECTION ELEVATED...BUT THE STRONGEST
STORMS COULD PRODUCE SOME SMALL HAIL. WARM AND MOIST ADVECTION WILL
CONTINUE INTO THE AFTERNOON AS THE SFC LOW TRACKS BY TO OUR WEST. MID
LEVEL WARMING IN THE WARM SECTOR WILL LIKELY LEAD TO A LULL IN
PRECIPITATION CHANCES SPREADING FROM SOUTHWEST TO NORTHEAST IN THE
AFTERNOON. WITH THE SYSTEM ALREADY A BIT STRONGER THAN CURRENTLY
FORECAST BY THE MODELS OPTED TO GO TOWARD THE WARMER END OF GUIDANCE
FOR MAX AND WINDS THIS AFTERNOON. SINCE CONVECTION WILL BE LARGELY
ISOLATED TO SCATTERED IN THE AFTERNOON AND STRONG WINDS FIELDS ARE
PROGGED ALOFT...GUSTS OF 35 TO 40 MPH MAY OCCUR OUTSIDE OF SHOWER AND
THUNDERSTORM ACTIVITY. WITH THIS IN MIND WENT WITH A LAKE WIND
ADVISORY FROM NOON UNTIL 7 PM TODAY. ANY CONVECTION BY MID TO LATE
AFTERNOON WOULD HAVE THE POTENTIAL TO BE IN THE FORM OF CLUSTERS OR
SUPERCELLS DUE TO STRONG WIND FIELDS ALOFT AND AMPLE SHEAR.
INSTABILITY IN THE AFTERNOON DOES APPEAR TO BE SOMEWHAT LIMITED
THOUGH AND SOME MID LEVEL CAPPING MAY BE PRESENT WITH NOT MUCH OF A
TRIGGER.
THE HIGHEST THREAT FOR SEVERE THUNDERSTORMS...A MODERATE RISK IN THE
DAY 1 SPC OUTLOOK APPEARS TO BE FROM LATE AFTERNOON OR EARLY EVENING
AND CONTINUING INTO THE EVENING IN ADVANCE OF AND POSSIBLY ALONG THE
SFC COLD FRONT. HOWEVER...GIVEN THE STRENGTH OF THE DEVELOPING SYSTEM
AND WIND FIELDS ALOFT...ANY STRONGER STORM DURING THE DAY COULD ALSO
PRODUCE DAMAGING WINDS...WITH ANY SUPERCELLS THAT DEVELOP HAVING A
LARGE HAIL AND ISOLATED TORNADO THREAT AS THE LOWER LEVELS EVENTUALLY
WILL BE MORE SATURATED. SUPERCELLS OR STORM CLUSTERS ONGOING LATE IN
THE AFTERNOON OVER CENTRAL AND PERHAPS INTO EASTERN KY SHOULD EVOLVE
INTO A QLCS TYPE SYSTEM DURING THE EVENING AS THE FRONT APPROACHES
AND RACE ACROSS THE CWA. THIS STORMS WOULD ALSO HAVE THE POTENTIAL TO
PRODUCE DAMAGING WINDS...LARGE HAIL...LOCALLY HEAVY RAIN AND ISOLATED
POSSIBLY STRONG TORNADOES. THE PERIOD OF THREAT FOR THE LARGEST HAIL
MAY BE FROM VERY LATE IN THE AFTERNOON THROUGH EARLY IN THE EVENING
AS CONSIDERABLE MID LEVEL DRY AIR IS PROGGED...LEADING TO LOW WBZ
HEIGHTS NEAR 8KFT LATE AFTERNOON AND EARLY IN THE EVENING. ANY
ROTATING CELLS WOULD HAVE MORE VIGOROUS UPDRAFTS HIS PERIOD AND WOULD
BRING A LARGE HAIL THREAT.
WITH THE FRONT AT LEAST BRIEFLY BECOMING PARALLEL TO THE UPPER LEVEL
FLOW...SOME TRAINING OF CONVECTION MAY OCCUR FROM LATE THIS AFTERNOON
THROUGH EARLY THIS EVENING ON TOP OF ALREADY WET GROUND FROM RECENT IN
MAY PLACES HEAVY PRECIPITATION. ANY TRAINING WOULD BRING A THREAT FOR
FLASH FLOODING. MODELS OVERALL HAVE TRENDED BACK ON THE QPF...BUT
LOCALLY HIGHER AMOUNTS ARE VERY POSSIBLE WITH THE STRONGER CELLS AND
IN ANY TRAINING. OPTED TO CHANGE THE START TIME OF THE FLASH FLOOD
WATCH TO 4 PM THIS AFTERNOON AS ANY CONVECTION THAT OCCURS FROM THAT
POINT ON WILL BE ON TOP OF RAINFALL FROM CONVECTION THIS AM THROUGH
EARLY THIS EVENING. WE ALSO OPTED TO MOVE THE EXPIRATION TIME TO 4 AM
ON SAT AM. MODELS HAVE TRENDED TOWARD A FASTER COLD FRONT...WITH ONLY
SOME ISOLATED TO SCATTERED LINGERING RAIN SHOWERS ON SAT MORNING.
SFC HIGH PRESSURE AND SUBSIDENCE BEHIND THE DEPARTING SYSTEM SHOULD
LEAD TO A MOSTLY DRY DAY ON SAT WITH COLD AND DRY AIR ADVECTION. MAX
T MAY NOT REACH 50 DEGREES ACROSS WESTERN SECTIONS AS A MUCH COLDER
AIRMASS WORKS INTO THE REGION.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 425 AM EST FRI MAR 2 2012
THE MODELS ARE IN GOOD AGREEMENT WITH AN AMPLIFIED LONG WAVE
PATTERN TO CONCLUDE THE WEEK...FOLLOWED BY A TEMPORARY TRANSITION TO
MORE ZONAL FLOW EARLY NEXT WEEK...AND THEN AMPLIFYING ONCE AGAIN
THEREAFTER.
A FULL LATITUDE TROUGH WILL BE MOVING THROUGH THE HEART OF THE
COUNTRY SATURDAY NIGHT...WITH WEAK HIGH PRESSURE HANGING ON AND
PROVIDING DRY WEATHER ACROSS EASTERN KENTUCKY. A COUPLE OF SHORT
WAVE TROUGHS WILL THEN CYCLE IN FROM THE NORTHWEST ON SUNDAY AND
THEN FROM SUNDAY NIGHT INTO MONDAY MORNING. THE LATTER WAVE IS MORE
INTENSE HAS MORE MOISTURE ASSOCIATED WITH IT. HAVE STUCK WITH LIKELY
POPS FOR SUNDAY NIGHT...WHICH SEEMS TO BE THE WINDOW OF BEST
FORCING. TEMPERATURE PROFILES WILL YIELD MAINLY SNOW FOR SUNDAY
NIGHT INTO MONDAY MORNING. AS MENTIONED PREVIOUSLY...A SLUSHY INCH
OF SNOW COULD MAKE FOR SLOW COMMUTE TIMES MONDAY MORNING.
ONCE THIS WAVE MOVES OUT MONDAY AFTERNOON...MODEST RIDGING AND
SURFACE HIGH PRESSURE BUILDING IN AND EVENTUALLY OFF THE EASTERN
SEABOARD WILL BRING MILDER AND GENERALLY DRIER WEATHER FOR THE REST
OF THE PERIOD. BY THE END OF THE WORK WEEK...THERE IS DISAGREEMENT
WITH THE TIMING AND EVOLUTION OF THE NEXT SYSTEM...WITH THE ECMWF
MORE AMPLIFIED IN A SPLIT FLOW PATTERN COMPARED TO THE GFS. HAVE
STUCK WITH THE INITIAL BLENDED GUIDANCE...WHICH KEEPS THE DRY
WEATHER GOING INTO THURSDAY.
FOR TEMPERATURES...GENERALLY SIDED WITH MORE OF A DIURNAL RANGE THEN
THE BLENDED GUIDANCE...ESPECIALLY FOR THE LOW TEMPERATURES IN THE
MORE SHELTERED VALLEYS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1234 PM EST FRI MAR 2 2012
A BREAK IN THE SHOWERS AND STORMS IS EXPECTED THIS AFTERNOON AND INTO
EARLY THIS EVENING. HOWEVER...GUSTY CONDITIONS WILL DEVELOP WITH
GUSTS UP TO 30 KNOTS POSSIBLE. THE THREAT FOR SHOWERS AND STORMS WILL
PUSH INTO EASTERN KENTUCKY AROUND 23Z...WITH THE GREATEST THREAT FOR
DOWNBURST WINDS BETWEEN 01 AND 03Z. GIVEN THE LIKELY STRONG
WINDS...HAVE PUT A TEMPO GROUP IN THE TAFS TO ACCOUNT FOR THESE
DOWNBURST WINDS. THE THREAT FOR THUNDERSTORMS WILL END BY MIDNIGHT
WITH SOME LEFTOVER SHOWERS. SKIES WILL BEGIN TO CLEAR OFF
TONIGHT...AND MAY NEED TO WATCH THE POTENTIAL FOR SOME FOG
DEVELOPMENT...BUT GIVEN THE COMPLEX WEATHER THIS EVENING...HAVE OPTED
TO WAIT ON INCLUDING ANY FOG FOR THE TIME BEING.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
LAKE WIND ADVISORY UNTIL 7 PM EST THIS EVENING FOR KYZ044-
050>052-058>060-068-069-079-080-083>088-104-106>120.
FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR KYZ058>060-068-069-
079-080-083>088-104-106>120.
&&
$$
UPDATE...KAS
SHORT TERM...JP
LONG TERM....GEOGERIAN
AVIATION...KAS
AREA FORECAST DISCUSSION
NWS JACKSON KY
1234 PM EST FRI MAR 2 2012
.UPDATE...
ISSUED AT 1234 PM EST FRI MAR 2 2012
DRY SLOT IS NOT NOSING INTO OUR SOUTHWEST COUNTIES...ENDING
PRECIPITATION THERE TEMPORARILY. THE SHOWERS AND STORMS SHOULD
CONTINUE TO DEPART TO THE NORTH AND EAST EARLY THIS
AFTERNOON...LEAVING MOST OF EASTERN KENTUCKY DRY FROM MID TO LATE
AFTERNOON. THIS WILL ALLOW TEMPERATURES TO WARM INTO THE MID 70S WITH
SOME BROKEN CIGS SPREADING ACROSS THE AREA. WITH DECENT MIXING
POTENTIAL...WE SHOULD SEE STRONG WINDS MIXING DOWN WITH SOME GUSTS UP
TO 40 MPH LIKELY. CANNOT RULE OUT AN ISOLATED STORM THIS
AFTERNOON...BUT THE MORE LIKELY SCENARIO IS ACTIVITY ARRIVING AHEAD
OF THE FRONTAL BOUNDARY LATER THIS EVENING.
MEANWHILE...SHOWERS AND STORMS ARE ALREADY DEVELOPING ALONG AND JUST
AHEAD OF THE FRONTAL BOUNDARY ACROSS MISSOURI AND ILLINOIS. BASED ON
LATEST HRRR...THIS ACTIVITY SHOULD PUSH INTO OUR BLUEGRASS COUNTIES
TOWARDS 5 OR 6 PM...THEN ACROSS THE REST OF EASTERN KENTUCKY THROUGH
10 PM. EARLY ON...STILL CONCERNED WITH DISCRETE SUPERCELLS...CAPABLE
OF DAMAGING WINDS...LARGE HAIL...AND A TORNADO. AS THE FRONT PUSHES
INTO THE REGION...A SQUALL LINE WILL LIKELY EVOLVE...WITH THE MAIN
THREAT STRAIGHT LINE DAMAGING WINDS. HOWEVER...A SPIN UP TORNADO
ALONG THE LINE IS POSSIBLE STILL. WITH THE FAST MOVEMENT OF
STORMS...THE SEVERE THREAT MAY BE OVER FOR MOST OF THE AREA BY
MIDNIGHT...WITH JUST SOME LEFT OVER RAIN PUSHING ACROSS OUR EASTERN
COUNTIES. HAVE LOWERED TEMPERATURES BEHIND THE FRONT TONIGHT...WITH
DECENT CLEARING SPREADING INTO THE AREA.
UPDATE ISSUED AT 1129 AM EST FRI MAR 2 2012
WIDESPREAD SHOWERS AND STORMS CONTINUE TO PROGRESS NORTHWARD ACROSS
THE CWA THIS MORNING...BUT A DISTINCT BACK EDGE AND DRY SLOT...BEHIND
THE ADVANCING WARM FRONT IS NOTED BACK ACROSS CENTRAL TENNESSEE.
USING THE TIMING TOOL...IT LOOKS LIKE THE ONGOING ACTIVITY SHOULD
PUSH NORTH AND EAST OF THE AREA BY 19Z...PROVIDING A DECENT BREAK FOR
MOST AREAS THIS AFTERNOON. HRRR IS HANDLING THE SITUATION FAIRLY
WELL. IT SHOWS SOME DISTINCT SUPERCELLS DEVELOPING OUT IN THE
BLUEGRASS BETWEEN 21 AND 22Z. THESE MAY IMPACT OUR NORTHEAST BLUEGRASS
COUNTIES AROUND THIS TIME. THESE STORMS WOULD OBVIOUSLY HAVE THE
POTENTIAL FOR LARGE HAIL...DAMAGING WINDS...AND TORNADOES. THESE
STORMS SHOULD DEVELOP OUT AHEAD OF THE ADVANCING COLD FRONT...WITH A
SQUALL LINE DEVELOPING ALONG THE ACTUAL FRONTAL BOUNDARY. THE MAIN
THREAT WITH THE SQUALL LINE WILL BE DAMAGING WINDS...BUT A BRIEF SPIN
UP ALONG THIS LINE IS POSSIBLE...PRODUCING A TORNADO. THE FRONTAL
BOUNDARY SHOULD HOLD OFF TO OUR WEST UNTIL AT LEAST 00Z. SO THE MAIN
THREAT PRIOR TO THAT TIME WILL BE THE DISCRETE SUPERCELLS IN THE WARM
SECTOR. WARM AND MUGGY CONDITIONS WILL DEVELOP HEADING INTO THIS
AFTERNOON WITH DEWPOINTS CLIMBING UP TO AROUND 60 WITH TEMPERATURES
AROUND 70. CERTAINLY JUICY AIR FOR THIS TIME OF YEAR. LAKE WIND
ADVISORY WILL CONTINUE AS ADVERTISED. FLASH FLOOD THREAT ALSO APPEARS
A BIT ENHANCED WITH EARLY DAY RAINFALL ADDING TO THE ALREADY SOAKED
GROUND AND BANK FULL CREEKS.
UPDATE ISSUED AT 837 AM EST FRI MAR 2 2012
SHOWERS AND THUNDERSTORMS HAVE BECOME MORE WIDESPREAD ACROSS THE AREA
OVER THE PAST HOUR. THUS...HAVE BROUGHT IN SOME HIGHER CATEGORICAL
POPS THROUGH THIS MORNING. ANOTHER BAND OF SHOWERS AND STORMS IS
KNOCKING AT OUR DOORSTEP...JUST NOW PUSHING INTO AREAS AROUND
MONTICELLO. AFTER THE MORNING CONVECTION...STILL LOOKING LIKE A
POTENTIAL BREAK BY MID AFTERNOON...BEFORE THE MAIN LINE OF CONVECTION
ARRIVES WITH THE FRONT BETWEEN 6 AND 9 PM. HAD SOME REPORTS OF
SUB-SEVERE HAIL THIS MORNING (HAIL LESS THAN AN INCH IN
DIAMETER)...BUT NOTHING SEVERE AS OF YET. MADE SOME TWEAKS TO
TEMPERATURES AND DEWPOINTS AS TEMPERATURES START TO WARM FROM SOUTH
TO NORTH AS THE FRONT PROGRESSES NORTHWARD.
UPDATE ISSUED AT 705 AM EST FRI MAR 2 2012
THE FORECAST IN GENERAL REMAINS ON TARGET...THOUGH CONVECTION UP UNTIL
THIS POINT HAS NOT BEEN ALL THAT WIDESPREAD. HOWEVER...ADDITIONAL
STRONG TO POSSIBLY SEVERE CONVECTION CONTINUES TO GET GOING TO OUR
SW IN NORTHERN MIDDLE TN AND SOME OF THIS ACTIVITY SHOULD LIFT NORTH
INTO THE REGION THROUGH MID TO LATE MORNING. ACTIVITY THIS MORNING
IS EXPECTED TO BE LARGELY ELEVATED AND EITHER WITH ONGOING CONVECTION
APPROACHING FROM CENTRAL KY AND THE CONVECTION APPROACHING FROM
MIDDLE TN WILL HAVE THE POTENTIAL TO PRODUCE HAIL...AND PERHAPS SOME
STRONGER WIND GUSTS.
ONCE THE WARM FRONT PASSES DURING THE MID AFTERNOON...THERE IS NOT A
LOT OF CONVECTIVE TRIGGERS...BUT ANY OUTFLOWS OR CONVECTION UPSTREAM
THAT MOVES IN OR ANY BREAKS IN THE CLOUDS COULD BE THE FOCUS FOR
INITIATION. OTHER THAN THE QUESTION OF A TRIGGER DURING MID AFTERNOON
AND SOME HINT OF MID LEVEL CAPPING IN THE FORECAST SOUNDINGS...IF
ANYTHING WERE TO GET GOING IT COULD BECOME SEVERE AS SHEAR WILL BE
AMPLE. IF THIS WERE TO BE IN SUPERCELL FORM...DAMAGING WINDS...LARGE
HAIL...AN EVEN A TORNADO WOULD BE POSSIBLE. IT STILL APPEARS THAT THE
MOST ORGANIZED SEVERE CONVECTION SHOULD OCCUR DURING THE LATE
AFTERNOON INTO THE EVENING HOURS.
HOURLY GRIDS WERE FRESHENED UP BASED ON THE LATEST TRENDS...BUT THE
PREVIOUS ZFP WAS STILL HANDLING THE SITUATION AT THIS TIME.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 430 AM EST FRI MAR 2 2012
SFC LOW PRESSURE OVER NE OKLAHOMA CONTINUES TO DEVELOP THIS MORNING
WITH A SFC WARM FRONT EXTENDING EAST INTO THE TN VALLEY REGION. AT
PRESENT IT IS ABOUT 2 MB STRONGER THAN THE 6Z NAM RUNS AND SLIGHTLY
STRONGER THAN MOST OF THE 0Z MODEL RUNS. THIS SYSTEM IS PROGGED TO
FURTHER DEEPEN AS IT TRACKS INTO THE GREAT LAKES THIS EVENING...WITH
THE MOST RAPID DEEPENING OCCURRING BETWEEN 18Z AND 0Z TONIGHT. THIS
SYSTEM WILL SEND A STRONG COLD FRONT INTO THE COMMONWEALTH...WITH THE
COLD FRONT REACHING THE JKL CWA DURING THE EVENING. THE COLD FRONT
SHOULD EXIT INTO VA EARLY ON AT AM.
DESPITE RELATIVELY CLOUD FREE CONDITIONS AT PRESENT WITH SOME VALLEY
LOCATIONS AT PRESENT IN THE 30S...A RATHER DRAMATIC RISE IN TEMPS AND
DEWPOINTS IS ANTICIPATED TODAY AS THE WARM FRONT LIFTS INTO THE
REGION FROM THE SOUTH AND WEST...MOVING NORTH AND EAST OF THE JKL CWA
BY EARLY TO MID AFTERNOON. DEWPOINTS ACROSS THE CWA ARE CURRENTLY IN
THE UPPER 20S AND 30S...BUT JUST SOUTH OF THE AREA DEWPOINTS IN THE
MID 40S ARE PRESENT ACROSS NORTHERN MIDDLE TN...THE 50S TO THE SOUTH
OF THAT AREA MIDDLE AND EAST TN AND THEN FURTHER SOUTH IN MS AND
AL...DEWPOINTS ARE IN THE LOWER 60S.
MODELS ALL PROG A RAPID INCREASE IN MOISTURE THIS MORNING AS THE WARM
FRONT MOVES INTO AND ACROSS THE AREA...AS HAS BEEN OCCURRING TO OUR SOUTH
AND WEST OVERNIGHT. AN AREA OF SHOWERS AND THUNDERSTORMS CONTINUES
TO DEVELOP FROM WEST CENTRAL KY SE INTO THE CUMBERLAND PLATEAU OF
MIDDLE TN. THIS CONVECTION SHOULD CONTINUE TO DEVELOP EARLY THIS
MORNING AND BECOME MORE WIDESPREAD AS MOISTURE TRANSPORT INCREASES AS
THE LOW LEVEL JET INCREASES. A ROUND OF SHOWERS AND AT LEAST SCATTERED
THUNDERSTORMS SHOULD OCCUR THIS MORNING. INSTABILITY IS PROGGED TO BE
RATHER LIMITED AND THIS CONVECTION ELEVATED...BUT THE STRONGEST
STORMS COULD PRODUCE SOME SMALL HAIL. WARM AND MOIST ADVECTION WILL
CONTINUE INTO THE AFTERNOON AS THE SFC LOW TRACKS BY TO OUR WEST. MID
LEVEL WARMING IN THE WARM SECTOR WILL LIKELY LEAD TO A LULL IN
PRECIPITATION CHANCES SPREADING FROM SOUTHWEST TO NORTHEAST IN THE
AFTERNOON. WITH THE SYSTEM ALREADY A BIT STRONGER THAN CURRENTLY
FORECAST BY THE MODELS OPTED TO GO TOWARD THE WARMER END OF GUIDANCE
FOR MAX AND WINDS THIS AFTERNOON. SINCE CONVECTION WILL BE LARGELY
ISOLATED TO SCATTERED IN THE AFTERNOON AND STRONG WINDS FIELDS ARE
PROGGED ALOFT...GUSTS OF 35 TO 40 MPH MAY OCCUR OUTSIDE OF SHOWER AND
THUNDERSTORM ACTIVITY. WITH THIS IN MIND WENT WITH A LAKE WIND
ADVISORY FROM NOON UNTIL 7 PM TODAY. ANY CONVECTION BY MID TO LATE
AFTERNOON WOULD HAVE THE POTENTIAL TO BE IN THE FORM OF CLUSTERS OR
SUPERCELLS DUE TO STRONG WIND FIELDS ALOFT AND AMPLE SHEAR.
INSTABILITY IN THE AFTERNOON DOES APPEAR TO BE SOMEWHAT LIMITED
THOUGH AND SOME MID LEVEL CAPPING MAY BE PRESENT WITH NOT MUCH OF A
TRIGGER.
THE HIGHEST THREAT FOR SEVERE THUNDERSTORMS...A MODERATE RISK IN THE
DAY 1 SPC OUTLOOK APPEARS TO BE FROM LATE AFTERNOON OR EARLY EVENING
AND CONTINUING INTO THE EVENING IN ADVANCE OF AND POSSIBLY ALONG THE
SFC COLD FRONT. HOWEVER...GIVEN THE STRENGTH OF THE DEVELOPING SYSTEM
AND WIND FIELDS ALOFT...ANY STRONGER STORM DURING THE DAY COULD ALSO
PRODUCE DAMAGING WINDS...WITH ANY SUPERCELLS THAT DEVELOP HAVING A
LARGE HAIL AND ISOLATED TORNADO THREAT AS THE LOWER LEVELS EVENTUALLY
WILL BE MORE SATURATED. SUPERCELLS OR STORM CLUSTERS ONGOING LATE IN
THE AFTERNOON OVER CENTRAL AND PERHAPS INTO EASTERN KY SHOULD EVOLVE
INTO A QLCS TYPE SYSTEM DURING THE EVENING AS THE FRONT APPROACHES
AND RACE ACROSS THE CWA. THIS STORMS WOULD ALSO HAVE THE POTENTIAL TO
PRODUCE DAMAGING WINDS...LARGE HAIL...LOCALLY HEAVY RAIN AND ISOLATED
POSSIBLY STRONG TORNADOES. THE PERIOD OF THREAT FOR THE LARGEST HAIL
MAY BE FROM VERY LATE IN THE AFTERNOON THROUGH EARLY IN THE EVENING
AS CONSIDERABLE MID LEVEL DRY AIR IS PROGGED...LEADING TO LOW WBZ
HEIGHTS NEAR 8KFT LATE AFTERNOON AND EARLY IN THE EVENING. ANY
ROTATING CELLS WOULD HAVE MORE VIGOROUS UPDRAFTS HIS PERIOD AND WOULD
BRING A LARGE HAIL THREAT.
WITH THE FRONT AT LEAST BRIEFLY BECOMING PARALLEL TO THE UPPER LEVEL
FLOW...SOME TRAINING OF CONVECTION MAY OCCUR FROM LATE THIS AFTERNOON
THROUGH EARLY THIS EVENING ON TOP OF ALREADY WET GROUND FROM RECENT IN
MAY PLACES HEAVY PRECIPITATION. ANY TRAINING WOULD BRING A THREAT FOR
FLASH FLOODING. MODELS OVERALL HAVE TRENDED BACK ON THE QPF...BUT
LOCALLY HIGHER AMOUNTS ARE VERY POSSIBLE WITH THE STRONGER CELLS AND
IN ANY TRAINING. OPTED TO CHANGE THE START TIME OF THE FLASH FLOOD
WATCH TO 4 PM THIS AFTERNOON AS ANY CONVECTION THAT OCCURS FROM THAT
POINT ON WILL BE ON TOP OF RAINFALL FROM CONVECTION THIS AM THROUGH
EARLY THIS EVENING. WE ALSO OPTED TO MOVE THE EXPIRATION TIME TO 4 AM
ON SAT AM. MODELS HAVE TRENDED TOWARD A FASTER COLD FRONT...WITH ONLY
SOME ISOLATED TO SCATTERED LINGERING RAIN SHOWERS ON SAT MORNING.
SFC HIGH PRESSURE AND SUBSIDENCE BEHIND THE DEPARTING SYSTEM SHOULD
LEAD TO A MOSTLY DRY DAY ON SAT WITH COLD AND DRY AIR ADVECTION. MAX
T MAY NOT REACH 50 DEGREES ACROSS WESTERN SECTIONS AS A MUCH COLDER
AIRMASS WORKS INTO THE REGION.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 425 AM EST FRI MAR 2 2012
THE MODELS ARE IN GOOD AGREEMENT WITH AN AMPLIFIED LONG WAVE
PATTERN TO CONCLUDE THE WEEK...FOLLOWED BY A TEMPORARY TRANSITION TO
MORE ZONAL FLOW EARLY NEXT WEEK...AND THEN AMPLIFYING ONCE AGAIN
THEREAFTER.
A FULL LATITUDE TROUGH WILL BE MOVING THROUGH THE HEART OF THE
COUNTRY SATURDAY NIGHT...WITH WEAK HIGH PRESSURE HANGING ON AND
PROVIDING DRY WEATHER ACROSS EASTERN KENTUCKY. A COUPLE OF SHORT
WAVE TROUGHS WILL THEN CYCLE IN FROM THE NORTHWEST ON SUNDAY AND
THEN FROM SUNDAY NIGHT INTO MONDAY MORNING. THE LATTER WAVE IS MORE
INTENSE HAS MORE MOISTURE ASSOCIATED WITH IT. HAVE STUCK WITH LIKELY
POPS FOR SUNDAY NIGHT...WHICH SEEMS TO BE THE WINDOW OF BEST
FORCING. TEMPERATURE PROFILES WILL YIELD MAINLY SNOW FOR SUNDAY
NIGHT INTO MONDAY MORNING. AS MENTIONED PREVIOUSLY...A SLUSHY INCH
OF SNOW COULD MAKE FOR SLOW COMMUTE TIMES MONDAY MORNING.
ONCE THIS WAVE MOVES OUT MONDAY AFTERNOON...MODEST RIDGING AND
SURFACE HIGH PRESSURE BUILDING IN AND EVENTUALLY OFF THE EASTERN
SEABOARD WILL BRING MILDER AND GENERALLY DRIER WEATHER FOR THE REST
OF THE PERIOD. BY THE END OF THE WORK WEEK...THERE IS DISAGREEMENT
WITH THE TIMING AND EVOLUTION OF THE NEXT SYSTEM...WITH THE ECMWF
MORE AMPLIFIED IN A SPLIT FLOW PATTERN COMPARED TO THE GFS. HAVE
STUCK WITH THE INITIAL BLENDED GUIDANCE...WHICH KEEPS THE DRY
WEATHER GOING INTO THURSDAY.
FOR TEMPERATURES...GENERALLY SIDED WITH MORE OF A DIURNAL RANGE THEN
THE BLENDED GUIDANCE...ESPECIALLY FOR THE LOW TEMPERATURES IN THE
MORE SHELTERED VALLEYS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1234 PM EST FRI MAR 2 2012
A BREAK IN THE SHOWERS AND STORMS IS EXPECTED THIS AFTERNOON AND INTO
EARLY THIS EVENING. HOWEVER...GUSTY CONDITIONS WILL DEVELOP WITH
GUSTS UP TO 30 KNOTS POSSIBLE. THE THREAT FOR SHOWERS AND STORMS WILL
PUSH INTO EASTERN KENTUCKY AROUND 23Z...WITH THE GREATEST THREAT FOR
DOWNBURST WINDS BETWEEN 01 AND 03Z. GIVEN THE LIKELY STRONG
WINDS...HAVE PUT A TEMPO GROUP IN THE TAFS TO ACCOUNT FOR THESE
DOWNBURST WINDS. THE THREAT FOR THUNDERSTORMS WILL END BY MIDNIGHT
WITH SOME LEFTOVER SHOWERS. SKIES WILL BEGIN TO CLEAR OFF
TONIGHT...AND MAY NEED TO WATCH THE POTENTIAL FOR SOME FOG
DEVELOPMENT...BUT GIVEN THE COMPLEX WEATHER THIS EVENING...HAVE OPTED
TO WAIT ON INCLUDING ANY FOG FOR THE TIME BEING.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
LAKE WIND ADVISORY UNTIL 7 PM EST THIS EVENING FOR KYZ044-
050>052-058>060-068-069-079-080-083>088-104-106>120.
FLASH FLOOD WATCH FROM 4 PM EST THIS AFTERNOON THROUGH LATE
TONIGHT FOR KYZ058>060-068-069-079-080-083>088-104-106>120.
&&
$$
UPDATE...KAS
SHORT TERM...JP
LONG TERM....GEOGERIAN
AVIATION...KAS
AREA FORECAST DISCUSSION
NWS JACKSON KY
1130 AM EST FRI MAR 2 2012
.UPDATE...
ISSUED AT 1129 AM EST FRI MAR 2 2012
WIDESPREAD SHOWERS AND STORMS CONTINUE TO PROGRESS NORTHWARD ACROSS
THE CWA THIS MORNING...BUT A DISTINCT BACK EDGE AND DRY SLOT...BEHIND
THE ADVANCING WARM FRONT IS NOTED BACK ACROSS CENTRAL TENNESSEE.
USING THE TIMING TOOL...IT LOOKS LIKE THE ONGOING ACTIVITY SHOULD
PUSH NORTH AND EAST OF THE AREA BY 19Z...PROVIDING A DECENT BREAK FOR
MOST AREAS THIS AFTERNOON. HRRR IS HANDLING THE SITUATION FAIRLY
WELL. IT SHOWS SOME DISTINCT SUPERCELLS DEVELOPING OUT IN THE
BLUEGRASS BETWEEN 21 AND 22Z. THESE MAY IMACT OUR NORTHEAST BLUEGRASS
COUNTIES AROUND THIS TIME. THESE STORMS WOULD OBVIOUSLY HAVE THE
POTENTIAL FOR LARGE HAIL...DAMAGING WINDS...AND TORNADOES. THESE
STORMS SHOULD DEVELOP OUT AHEAD OF THE ADVANCING COLD FRONT...WITH A
SQUALL LINE DEVELOPING ALONG THE ACTUAL FRONTAL BOUNDARY. THE MAIN
THREAT WITH THE SQUALL LINE WILL BE DAMAGING WINDS...BUT A BRIEF SPIN
UP ALONG THIS LINE IS POSSIBLE...PRODUCING A TORNADO. THE FRONTAL
BOUNDARY SHOULD HOLD OFF TO OUR WEST UNTIL AT LEAST 00Z. SO THE MAIN
THREAT PRIOR TO THAT TIME WILL BE THE DISCRETE SUPERCELLS IN THE WARM
SECTOR. WARM AND MUGGY CONDITIONS WILL DEVELOP HEADING INTO THIS
AFTERNOON WITH DEWPOINTS CLIMBING UP TO AROUND 60 WITH TEMPERATURES
AROUND 70. CERTAINLY JUICY AIR FOR THIS TIME OF YEAR. LAKE WIND
ADVISORY WILL CONTINUE AS ADVERTISED. FLASH FLOOD THREAT ALSO APPEARS
A BIT ENHANCED WITH EARLY DAY RAINFALL ADDING TO THE ALREADY SOAKED
GROUND AND BANK FULL CREEKS.
UPDATE ISSUED AT 837 AM EST FRI MAR 2 2012
SHOWERS AND THUNDERSTORMS HAVE BECOME MORE WIDESPREAD ACROSS THE AREA
OVER THE PAST HOUR. THUS...HAVE BROUGHT IN SOME HIGHER CATEGORICAL
POPS THROUGH THIS MORNING. ANOTHER BAND OF SHOWERS AND STORMS IS
KNOCKING AT OUR DOORSTEP...JUST NOW PUSHING INTO AREAS AROUND
MONTICELLO. AFTER THE MORNING CONVECTION...STILL LOOKING LIKE A
POTENTIAL BREAK BY MID AFTERNOON...BEFORE THE MAIN LINE OF CONVECTION
ARRIVES WITH THE FRONT BETWEEN 6 AND 9 PM. HAD SOME REPORTS OF
SUBSEVERE HAIL THIS MORNING (HAIL LESS THAN AN INCH IN
DIAMETER)...BUT NOTHING SEVERE AS OF YET. MADE SOME TWEAKS TO
TEMPERATURES AND DEWPOINTS AS TEMPERATURES START TO WARM FROM SOUTH
TO NORTH AS THE FRONT PROGRESSES NORTHWARD.
UPDATE ISSUED AT 705 AM EST FRI MAR 2 2012
THE FORECAST IN GENERAL REMAINS ON TARGET...THOUGH CONVECTION UP UNTIL
THIS POINT HAS NOT BEEN ALL THAT WIDESPREAD. HOWEVER...ADDITIONAL
STRONG TO POSSIBLY SEVERE CONVECTION CONTINUES TO GET GOING TO OUR
SW IN NORTHERN MIDDLE TN AND SOME OF THIS ACTIVITY SHOULD LIFT NORTH
INTO THE REGION THROUGH MID TO LATE MORNING. ACTIVITY THIS MORNING
IS EXPECTED TO BE LARGELY ELEVATED AND EITHER WITH ONGOING CONVECTION
APPROACHING FROM CENTRAL KY AND THE CONVECTION APPROACHING FROM
MIDDLE TN WILL HAVE THE POTENTIAL TO PRODUCE HAIL...AND PERHAPS SOME
STRONGER WIND GUSTS.
ONCE THE WARM FRONT PASSES DURING THE MID AFTERNOON...THERE IS NOT A
LOT OF CONVECTIVE TRIGGERS...BUT ANY OUTFLOWS OR CONVECTION UPSTREAM
THAT MOVES IN OR ANY BREAKS IN THE CLOUDS COULD BE THE FOCUS FOR
INITIATION. OTHER THAN THE QUESTION OF A TRIGGER DURING MID AFTERNOON
AND SOME HINT OF MID LEVEL CAPPING IN THE FORECAST SOUNDINGS...IF
ANYTHING WERE TO GET GOING IT COULD BECOME SEVERE AS SHEAR WILL BE
AMPLE. IF THIS WERE TO BE IN SUPERCELL FORM...DAMAGING WINDS...LARGE
HAIL...AN EVEN A TORNADO WOULD BE POSSIBLE. IT STILL APPEARS THAT THE
MOST ORGANIZED SEVERE CONVECTION SHOULD OCCUR DURING THE LATE
AFTERNOON INTO THE EVENING HOURS.
HOURLY GRIDS WERE FRESHENED UP BASED ON THE LATEST TRENDS...BUT THE
PREVIOUS ZFP WAS STILL HANDLING THE SITUATION AT THIS TIME.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 430 AM EST FRI MAR 2 2012
SFC LOW PRESSURE OVER NE OKLAHOMA CONTINUES TO DEVELOP THIS MORNING
WITH A SFC WARM FRONT EXTENDING EAST INTO THE TN VALLEY REGION. AT
PRESENT IT IS ABOUT 2 MB STRONGER THAN THE 6Z NAM RUNS AND SLIGHTLY
STRONGER THAN MOST OF THE 0Z MODEL RUNS. THIS SYSTEM IS PROGGED TO
FURTHER DEEPEN AS IT TRACKS INTO THE GREAT LAKES THIS EVENING...WITH
THE MOST RAPID DEEPENING OCCURRING BETWEEN 18Z AND 0Z TONIGHT. THIS
SYSTEM WILL SEND A STRONG COLD FRONT INTO THE COMMONWEALTH...WITH THE
COLD FRONT REACHING THE JKL CWA DURING THE EVENING. THE COLD FRONT
SHOULD EXIT INTO VA EARLY ON AT AM.
DESPITE RELATIVELY CLOUD FREE CONDITIONS AT PRESENT WITH SOME VALLEY
LOCATIONS AT PRESENT IN THE 30S...A RATHER DRAMATIC RISE IN TEMPS AND
DEWPOINTS IS ANTICIPATED TODAY AS THE WARM FRONT LIFTS INTO THE
REGION FROM THE SOUTH AND WEST...MOVING NORTH AND EAST OF THE JKL CWA
BY EARLY TO MID AFTERNOON. DEWPOINTS ACROSS THE CWA ARE CURRENTLY IN
THE UPPER 20S AND 30S...BUT JUST SOUTH OF THE AREA DEWPOINTS IN THE
MID 40S ARE PRESENT ACROSS NORTHERN MIDDLE TN...THE 50S TO THE SOUTH
OF THAT AREA MIDDLE AND EAST TN AND THEN FURTHER SOUTH IN MS AND
AL...DEWPOINTS ARE IN THE LOWER 60S.
MODELS ALL PROG A RAPID INCREASE IN MOISTURE THIS MORNING AS THE WARM
FRONT MOVES INTO AND ACROSS THE AREA...AS HAS BEEN OCCURRING TO OUR SOUTH
AND WEST OVERNIGHT. AN AREA OF SHOWERS AND THUNDERSTORMS CONTINUES
TO DEVELOP FROM WEST CENTRAL KY SE INTO THE CUMBERLAND PLATEAU OF
MIDDLE TN. THIS CONVECTION SHOULD CONTINUE TO DEVELOP EARLY THIS
MORNING AND BECOME MORE WIDESPREAD AS MOISTURE TRANSPORT INCREASES AS
THE LOW LEVEL JET INCREASES. A ROUND OF SHOWERS AND AT LEAST SCATTERED
THUNDERSTORMS SHOULD OCCUR THIS MORNING. INSTABILITY IS PROGGED TO BE
RATHER LIMITED AND THIS CONVECTION ELEVATED...BUT THE STRONGEST
STORMS COULD PRODUCE SOME SMALL HAIL. WARM AND MOIST ADVECTION WILL
CONTINUE INTO THE AFTERNOON AS THE SFC LOW TRACKS BY TO OUR WEST. MID
LEVEL WARMING IN THE WARM SECTOR WILL LIKELY LEAD TO A LULL IN
PRECIPITATION CHANCES SPREADING FROM SOUTHWEST TO NORTHEAST IN THE
AFTERNOON. WITH THE SYSTEM ALREADY A BIT STRONGER THAN CURRENTLY
FORECAST BY THE MODELS OPTED TO GO TOWARD THE WARMER END OF GUIDANCE
FOR MAX AND WINDS THIS AFTERNOON. SINCE CONVECTION WILL BE LARGELY
ISOLATED TO SCATTERED IN THE AFTERNOON AND STRONG WINDS FIELDS ARE
PROGGED ALOFT...GUSTS OF 35 TO 40 MPH MAY OCCUR OUTSIDE OF SHOWER AND
THUNDERSTORM ACTIVITY. WITH THIS IN MIND WENT WITH A LAKE WIND
ADVISORY FROM NOON UNTIL 7 PM TODAY. ANY CONVECTION BY MID TO LATE
AFTERNOON WOULD HAVE THE POTENTIAL TO BE IN THE FORM OF CLUSTERS OR
SUPERCELLS DUE TO STRONG WIND FIELDS ALOFT AND AMPLE SHEAR.
INSTABILITY IN THE AFTERNOON DOES APPEAR TO BE SOMEWHAT LIMITED
THOUGH AND SOME MID LEVEL CAPPING MAY BE PRESENT WITH NOT MUCH OF A
TRIGGER.
THE HIGHEST THREAT FOR SEVERE THUNDERSTORMS...A MODERATE RISK IN THE
DAY 1 SPC OUTLOOK APPEARS TO BE FROM LATE AFTERNOON OR EARLY EVENING
AND CONTINUING INTO THE EVENING IN ADVANCE OF AND POSSIBLY ALONG THE
SFC COLD FRONT. HOWEVER...GIVEN THE STRENGTH OF THE DEVELOPING SYSTEM
AND WIND FIELDS ALOFT...ANY STRONGER STORM DURING THE DAY COULD ALSO
PRODUCE DAMAGING WINDS...WITH ANY SUPERCELLS THAT DEVELOP HAVING A
LARGE HAIL AND ISOLATED TORNADO THREAT AS THE LOWER LEVELS EVENTUALLY
WILL BE MORE SATURATED. SUPERCELLS OR STORM CLUSTERS ONGOING LATE IN
THE AFTERNOON OVER CENTRAL AND PERHAPS INTO EASTERN KY SHOULD EVOLVE
INTO A QLCS TYPE SYSTEM DURING THE EVENING AS THE FRONT APPROACHES
AND RACE ACROSS THE CWA. THIS STORMS WOULD ALSO HAVE THE POTENTIAL TO
PRODUCE DAMAGING WINDS...LARGE HAIL...LOCALLY HEAVY RAIN AND ISOLATED
POSSIBLY STRONG TORNADOES. THE PERIOD OF THREAT FOR THE LARGEST HAIL
MAY BE FROM VERY LATE IN THE AFTERNOON THROUGH EARLY IN THE EVENING
AS CONSIDERABLE MID LEVEL DRY AIR IS PROGGED...LEADING TO LOW WBZ
HEIGHTS NEAR 8KFT LATE AFTERNOON AND EARLY IN THE EVENING. ANY
ROTATING CELLS WOULD HAVE MORE VIGOROUS UPDRAFTS HIS PERIOD AND WOULD
BRING A LARGE HAIL THREAT.
WITH THE FRONT AT LEAST BRIEFLY BECOMING PARALLEL TO THE UPPER LEVEL
FLOW...SOME TRAINING OF CONVECTION MAY OCCUR FROM LATE THIS AFTERNOON
THROUGH EARLY THIS EVENING ON TOP OF ALREADY WET GROUND FROM RECENT IN
MAY PLACES HEAVY PRECIPITATION. ANY TRAINING WOULD BRING A THREAT FOR
FLASH FLOODING. MODELS OVERALL HAVE TRENDED BACK ON THE QPF...BUT
LOCALLY HIGHER AMOUNTS ARE VERY POSSIBLE WITH THE STRONGER CELLS AND
IN ANY TRAINING. OPTED TO CHANGE THE START TIME OF THE FLASH FLOOD
WATCH TO 4 PM THIS AFTERNOON AS ANY CONVECTION THAT OCCURS FROM THAT
POINT ON WILL BE ON TOP OF RAINFALL FROM CONVECTION THIS AM THROUGH
EARLY THIS EVENING. WE ALSO OPTED TO MOVE THE EXPIRATION TIME TO 4 AM
ON SAT AM. MODELS HAVE TRENDED TOWARD A FASTER COLD FRONT...WITH ONLY
SOME ISOLATED TO SCATTERED LINGERING RAIN SHOWERS ON SAT MORNING.
SFC HIGH PRESSURE AND SUBSIDENCE BEHIND THE DEPARTING SYSTEM SHOULD
LEAD TO A MOSTLY DRY DAY ON SAT WITH COLD AND DRY AIR ADVECTION. MAX
T MAY NOT REACH 50 DEGREES ACROSS WESTERN SECTIONS AS A MUCH COLDER
AIRMASS WORKS INTO THE REGION.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 425 AM EST FRI MAR 2 2012
THE MODELS ARE IN GOOD AGREEMENT WITH AN AMPLIFIED LONG WAVE
PATTERN TO CONCLUDE THE WEEK...FOLLOWED BY A TEMPORARY TRANSITION TO
MORE ZONAL FLOW EARLY NEXT WEEK...AND THEN AMPLIFYING ONCE AGAIN
THEREAFTER.
A FULL LATITUDE TROUGH WILL BE MOVING THROUGH THE HEART OF THE
COUNTRY SATURDAY NIGHT...WITH WEAK HIGH PRESSURE HANGING ON AND
PROVIDING DRY WEATHER ACROSS EASTERN KENTUCKY. A COUPLE OF SHORT
WAVE TROUGHS WILL THEN CYCLE IN FROM THE NORTHWEST ON SUNDAY AND
THEN FROM SUNDAY NIGHT INTO MONDAY MORNING. THE LATTER WAVE IS MORE
INTENSE HAS MORE MOISTURE ASSOCIATED WITH IT. HAVE STUCK WITH LIKELY
POPS FOR SUNDAY NIGHT...WHICH SEEMS TO BE THE WINDOW OF BEST
FORCING. TEMPERATURE PROFILES WILL YIELD MAINLY SNOW FOR SUNDAY
NIGHT INTO MONDAY MORNING. AS MENTIONED PREVIOUSLY...A SLUSHY INCH
OF SNOW COULD MAKE FOR SLOW COMMUTE TIMES MONDAY MORNING.
ONCE THIS WAVE MOVES OUT MONDAY AFTERNOON...MODEST RIDGING AND
SURFACE HIGH PRESSURE BUILDING IN AND EVENTUALLY OFF THE EASTERN
SEABOARD WILL BRING MILDER AND GENERALLY DRIER WEATHER FOR THE REST
OF THE PERIOD. BY THE END OF THE WORK WEEK...THERE IS DISAGREEMENT
WITH THE TIMING AND EVOLUTION OF THE NEXT SYSTEM...WITH THE ECMWF
MORE AMPLIFIED IN A SPLIT FLOW PATTERN COMPARED TO THE GFS. HAVE
STUCK WITH THE INITIAL BLENDED GUIDANCE...WHICH KEEPS THE DRY
WEATHER GOING INTO THURSDAY.
FOR TEMPERATURES...GENERALLY SIDED WITH MORE OF A DIURNAL RANGE THEN
THE BLENDED GUIDANCE...ESPECIALLY FOR THE LOW TEMPERATURES IN THE
MORE SHELTERED VALLEYS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 705 AM EST FRI MAR 2 2012
AN APPROACHING WARM FRONT IS BRINGING AN INCREASE AND LOWERING IN
CLOUDS AT PRESENT ALONG WITH SCATTERED TO NUMEROUS SHOWERS AND
ISOALTED THUNDERSTORMS. MOST OF THE THUNDERSTORMS IN THE NEXT COUPLE
OF HOURS SHOULD REMAIN NORTH AND NORTHWEST OF THE TAF SITES. THE
THREAT FOR SHOWERS BY DAWN...MAINLY ACROSS THE SE CWA. IT STILL
APPEARS ADDITIONAL SHOWERS AND ISOLATED TO SCATTERED THUNDERSTORMS
ARE ANTICIPATED THROUGH ABOUT 18Z TO 19Z AS THE WARM FRONT SHIFTS
NORTH ACROSS THE AREA. A LULL IN THE PRECIP THREAT APPEARS TO EXIST
BETWEEN ABOUT 19Z AND 01Z.
FOCUS DURING THE LAST 12 TO 18 HRS OF THE PERIOD CENTERES AROUND A
LOW PRESSURE SYSTEM THAT WILL TRACK NW OF THE AREA AND SEND A COLD
FRONT ACROSS THE COMMONWEALTH THIS AFTERNOON AND EVENING. THERE IS
STILL SOME UNCERTAINTY OVER THE EVOLUTION OF THIS SYSTEM...PARTICULARLY
TIMING AND STRENGTH OF CONVECTIVE DEVELOPMENT...BUT MODELS CONTINUE
TO INDICATE A THREAT FOR SEVERE WEATHER...GENERALLY DURING THE
AFTERNOON AND PARTICULARLY THE EVENING HOURS OVER ERN KY. SOUTH WINDS
WILL BEGIN RAMPING UP AFTER 12Z...AS THE LOW LEVEL INVERSION WILL
GRADUALLY MIX OUT...BUT A BIT LATER THAN TYPICAL DUE TO PRECIP
KEEPING THE LOW LEVEL INVERSION IN PLACE WELL INTO THE AM. THIS WILL
CREATE A POTENTIAL FOR LLWS LINGERING THROUGH ABOUT 14Z OR 15Z OR SO.
CIGS WILL CONTINUE TO BUILD DOWN INTO THE MVFR RANGE AS THE MORNING
PROGRESSES AS THE ATMOSPHERE SATURATES FROM THE TOP DOWN. AROUND THE
END TIME OF THE PRECIP ASSOCIATED WITH THE WARM FRONT...OR ABOUT 17Z
AND AFTER SUSTAINED WINDS AND GUSTS SHOULD PICK UP WITH SUSTAINED
WINDS OF 10 TO 20KT AND SOME GUSTS NEARING 30KT POSSIBLE BETWEEN
ABOUT 17Z AND 01Z...EVEN OUTSIDE OF CONVECTION. CONFIDENCE AND
TIMING IN WIDESPREAD ORGANIZED SEVERE CONVECTION BEFORE 22Z IS RATHER
LOW...BUT A LINE OF STRONG TO SEVERE THUNDERSTORMS SHOULD AFFECT THE
TAF SITES BETWEEN 0Z AND 6Z. EXCEPT FOR THIS PERIOD... HIGHLIGHTED
THE THREAT FOR CONVECTION WITH CB GROUPS AND OR VCTS. MVFR CIGS SHOULD
LINGER BEHIND THE FRONT UNTIL THE END OF THE PERIOD.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
LAKE WIND ADVISORY UNTIL 7 PM EST THIS EVENING FOR KYZ044-
050>052-058>060-068-069-079-080-083>088-104-106>120.
FLASH FLOOD WATCH FROM 4 PM EST THIS AFTERNOON THROUGH LATE
TONIGHT FOR KYZ058>060-068-069-079-080-083>088-104-106>120.
&&
$$
UPDATE...KAS
SHORT TERM...JP
LONG TERM....GEOGERIAN
AVIATION...JP
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
345 PM EST FRI MAR 2 2012
.SYNOPSIS...
A STRONG LOW PRESSURE SYSTEM WILL BRING SHOWERS AND THUNDERSTORMS
THIS EVENING WITH STRONG TO SEVERE THUNDERSTORMS POSSIBLE TONIGHT.
IN THE WAKE OF THE FRONT, COLDER AIR WILL MOVE INTO THE AREA
WITH GUSTY WINDS EXPECTED ON SATURDAY AND SNOW SHOWERS POSSIBLE ON
SUNDAY.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
THE LATEST RUC MID-LEVEL ANALYSIS INDICATES A SOUTHWESTERLY FLOW
ACROSS THE UPPER OHIO VALLEY. AT THE SURFACE, A 990MB SURFACE LOW
IS CENTERED IN INDIANA WITH A WARM FRONT EXTENDING SOUTHEASTWARD
ACROSS KENTUCKY AND WEST VIRGINIA.
THIS EVENING...THE WARM FRONT WILL APPROACH THE AREA FROM THE
SOUTHWEST AHEAD OF A COLD FRONT. ELEVATED INSTABILITY (MUCAPE
AROUND 500 J/KG) SLIDING INTO THE AREA WILL ALLOW FOR SHOWERS
WITH THE CHANCE OF THUNDERSTORMS. DESPITE STRONG SHEAR, LIMITED
INSTABILITY AND DRY LOW-LEVELS WILL PREVENT THE SEVERE THREAT
INITIALLY.
TONIGHT...THE STRENGTHENING SURFACE LOW WILL MOVE INTO THE GREAT
LAKES, SWINGING A COLD FRONT ACROSS THE UPPER OHIO VALLEY. DESPITE
MINIMAL SBCAPE, 50-60KT 850MB LOW-LEVEL JET PUSHING INTO THE AREA
SUPPORTS THE POSSIBLE DEVELOPMENT OF CONVECTION INTO A SQUALL
LINE JUST AHEAD OF THE COLD FRONT. IF THIS DEVELOPS, THIS WILL
BRING THE PRIMARY THREAT OF DAMAGING WINDS TO THE AREA. THE
NAM/SREF ARE INDICATING 0-1KM SHEAR OF 40KTS SO WITH THIS IN
CONSIDERATION AND 5-10% SPC TORNADO THREAT HAVE MENTION OF
ISOLATED TORNADOES IN HWO FOR PORTIONS OF EASTERN OHIO. SHOWERS
AND THUNDERSTORMS WILL COME TO AN END AS THE FRONT PUSHES EAST OF
THE RIDGES NEAR DAWN ON THURSDAY. AS THE PRESSURE GRADIENT
TIGHTENS, SYNOPTIC WINDS WILL INCREASE, WITH GUSTS UP TO 40 MPH
OVERNIGHT. OVERNIGHT LOWS ARE NEAR A MAV/MET BLEND, COOLING TO A
FEW DEGREES BELOW NORMAL AS COLD AIR ADVECTS IN BEHIND THE FRONT.
WITH PWATS INCREASING TO AROUND AN INCH (2 STANDARD DEVIATIONS ABOVE
SEASONAL NORMAL) AND 3HR FFG OF 1.0-1.5 INCHES FROM PREVIOUS
RAINFALL ON WEDNESDAY, THERE IS A FLASH FLOOD THREAT IN
LOCALIZED THUNDERSTORMS FOR PORTIONS OF NORTH-CENTRAL WV, EASTERN
OHIO, EXTREME SOUTHWEST PA, AND WESTERN MD. THUS, A FLASH FLOOD
WATCH REMAINS THESE AREAS.
&&
.SHORT TERM /SATURDAY THROUGH MONDAY NIGHT/...
THERE IS OPERATIONAL MODEL AGREEMENT THAT THE SURFACE LOW WILL
CONTINUE TO PULL FURTHER NORTHEAST OF THE AREA WITH A DEEP LAYER OF
DRY AIR BUILD INTO THE REGION ON SATURDAY. A TIGHTENED PRESSURE GRADIENT
WILL REMAIN ACROSS THE UPPER OHIO VALLEY. THIS WILL ALLOW FOR
GUSTY WINDS TO INCREASE WITH DIURNAL MIXING BY LATE MORNING INTO
THE AFTERNOON. BUFKIT SUPPORTS WINDS GUSTING TO 30 TO 40 MPH AND
AT THIS TIME GUSTS ARE FORECAST TO BE JUST BELOW WIND ADVISORY
CRITERIA.
SATURDAY NIGHT...THE LOW-LEVEL FLOW WILL BACK TO WEST-NORTHWESTERLY
WITH COLD AIR ADVECTION SERVING TO INITIATE SCATTERED SNOW
SHOWERS. BEST CHANCE WILL BE ALONG THE I-80 CORRIDOR AND EASTERN
RIDGES WITH LOW CHANCE POPS ELSEWHERE. THE PRESSURE GRADIENT WILL
LOOSEN AND ALLOW FOR WIND GUSTS TO DECREASE.
UPPER LEVEL SHORTWAVE WILL MOVE ACROSS THE EASTERN GREAT LAKES
SUNDAY. 850MB TEMPERATURES WILL BE COLD ENOUGH TO ALLOW FOR AT LEAST
SOME LAKE ENHANCEMENT...IF NOT LAKE EFFECT SHOWERS. WINDS MAY NOT
HAVE ENOUGH OF A NORTHERLY COMPONENT ON SUNDAY TO TAP INTO MUCH LAKE
ERIE MOISTURE OUTSIDE OF THE RIDGES AND I-80 CORRIDOR...AND THIS MAY
LIMIT SNOWFALL TOTALS. BETTER CHANCE FOR SNOWFALL MAY OCCUR SUNDAY
NIGHT AS 850MB TEMPS CONTINUE TO DECREASE AND WINDS BECOME MORE
NORTHWESTERLY. PRECIPITATION SHOULD DIMINISH ON MONDAY WITH UPPER
LEVEL SUPPORT MOVING OFF TO THE EAST. TEMPERATURES THROUGH THIS
PERIOD WILL BE 5-10 DEGREES BELOW NORMAL.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
HIGH PRESSURE WILL DOMINATE THE EAST COAST TUESDAY AND
WEDNESDAY...KEEPING CONDITIONS DRY. LOW PRESSURE ACROSS CANADA WILL
SLOWLY DRAG A COLD FRONT ACROSS THE EASTERN UNITED STATES. USUAL
DIFFERENCES IN MODEL TIMING FOR THE EXTENDED FORECAST...BUT MODELS
ARE IN BETTER AGREEMENT THAN NORMAL. FRONT SHOULD ARRIVE DURING THE
DAY THURSDAY...WITH RAIN CONTINUING INTO FRIDAY. EXPECT NEAR
CLIMATOLOGICAL TEMPS ON TUESDAY...WITH WELL ABOVE NORMAL TEMPS FOR
WEDNESDAY AND THURSDAY...AND SLIGHTLY COOLER BEHIND THE COLD FRONT
ON FRIDAY.
&&
.AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
RAIN ASSOCIATED WITH A WARM FRONT WILL OVERSPREAD TERMINALS FROM
SOUTH TO NORTH DURING THE MID TO LATE AFTERNOON HOURS. AT 18Z TAF
ISSUANCE...THERE WAS LITTLE ORGANIZED CONVECTION OCCURRING WITH THE
FRONT...SO HAVE ONLY GONE WITH A CB MENTION AT THIS TIME. A
THUNDERSTORM CANNOT BE RULED OUT WITH THE WARM FRONT. SOME LOW LEVEL
WIND SHEAR COULD OCCUR DURING THIS TIME WITH SURFACE WINDS OUT OF
THE S-SE AND WINDS ALOFT OUT OF THE S-SW...BUT HAVE CHOSEN TO
HIGHLIGHT WIND GUSTS AT THIS TIME. THERE COULD BE A SLIGHT GAP IN
RAINFALL BETWEEN THE WARM FRONT DURING THE LATE AFTERNOON AND THE
COLD FRONT ARRIVING THIS EVENING FROM THE WEST. THE COLD FRONT WILL
BE QUITE STRONG...AND THERE IS THE POSSIBILITY FOR HAIL AND 50KT
WINDS IN THUNDERSTORMS AS THE FRONT PASSES. DID NOT HAVE ENOUGH
CONFIDENCE IN TIMING TO SPECIFICALLY INCLUDE TEMPO TSRA IN TAFS AT
THIS TIME.
ONCE COLD FRONT PASSES BETWEEN 03-06Z...CLOUDS WILL BEGIN TO SCATTER
OUT...BUT GUSTS WILL REMAIN 25-30 KTS OUT OF THE SOUTHWEST.
SUSTAINED WINDS WILL DROP SLIGHTLY OVERNIGHT...BUT BY LATE MORNING
MANY SITES WILL APPROACH WESTERLY 20G30KT...WITH HIGHER VALUES TO
THE NORTH. ANOTHER LINE OF CLOUDS WILL APPROACH...BUT CONDITIONS
WILL REMAIN VFR WITH NO PRECIPITATION.
OUTLOOK...SATURDAY AFTERNOON THROUGH WEDNESDAY...
CONDITIONS WILL REMAIN VFR SATURDAY AFTERNOON INTO SATURDAY EVENING
IN ADVANCE OF AN UPPER LEVEL SYSTEM MOVING ACROSS THE GREAT LAKES.
EXPECT RESTRICTIONS IN SNOW SHOWERS SATURDAY NIGHT INTO SUNDAY
NIGHT. TERMINALS SOUTH OF PITTSBURGH COULD REMAIN UNDER RESTRICTIONS
IN SNOW SHOWERS MONDAY. HIGH PRESSURE WILL BRING VFR CONDITIONS FOR
MONDAY NIGHT THROUGH WEDNESDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR MDZ001.
OH...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR OHZ068-069.
PA...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR PAZ031-073>076.
WV...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR WVZ004-012-021>023-
041.
&&
$$
AREA FORECAST DISCUSSION...RESENT
NWS PITTSBURGH PA
204 PM EST FRI MAR 2 2012
.SYNOPSIS...
A STRONG LOW PRESSURE SYSTEM WILL BRING SHOWERS AND THUNDERSTORMS
THIS AFTERNOON WITH STRONG TO SEVERE THUNDERSTORMS POSSIBLE
TONIGHT. IN THE WAKE OF THE FRONT, COLDER AIR WILL MOVE INTO THE
AREA WITH GUSTY WINDS EXPECTED ON SATURDAY AND SNOW SHOWERS
POSSIBLE ON SUNDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AN EARLY AFTERNOON ENHANCED SHORT TERM FORECAST HAS BEEN ISSUED TO
PIN DOWN TIMING ON SHOWERS AND POSSIBLE THUNDERSTORMS EARLY AND
MORE ORGANIZED CONVECTION TONIGHT AS IT CROSSES THE AREA AHEAD OF
A COLD FRONT.
THE LATEST RUC MID-LEVEL ANALYSIS INDICATES A SOUTHWESTERLY FLOW
ACROSS THE UPPER OHIO VALLEY AHEAD OF A CLOSED LOW ACROSS THE
NORTHERN PLAINS. AT THE SURFACE, A 992MB SURFACE LOW IS CENTERED
ACROSS SOUTHERN ILLINOIS WITH A WARM FRONT EXTENDING EASTWARD
ACROSS KENTUCKY AND WEST VIRGINIA.
THIS AFTERNOON...THE WARM FRONT WILL PUSH NORTHEAST TOWARD THE
AREA, WITH ELEVATED INSTABILITY (MUCAPE AROUND 500 J/KG) SLIDING
INTO EASTERN OHIO AND NORTH-CENTRAL WV. THIS WILL ALLOW FOR
SHOWERS WITH THE CHANCE OF THUNDERSTORMS TO PUSH INTO THE AREA.
DESPITE STRONG SHEAR, LIMITED INSTABILITY AND DRY LOW-LEVELS WILL
PREVENT SEVERE THREAT EARLY.
TONIGHT...THE STRENGTHENING SURFACE LOW WILL MOVE INTO THE GREAT
LAKES, SWINGING A COLD FRONT ACROSS THE UPPER OHIO VALLEY. WITH
SBCAPE AROUND 500 J/KG AND A 50KT 850MB LOW-LEVEL JET, 4KM WRF-
NMM SUPPORTS THE POSSIBLE DEVELOPMENT OF A SQUALL LINE JUST AHEAD
OF THE COLD FRONT PUSHING ACROSS THE AREA. THIS WILL BRING THE
PRIMARY THREAT OF DAMAGING WINDS TO THE AREA. THE NAM/SREF ARE
INDICATING 0-1KM SHEAR OF 40KTS AND 0-1 SRH AT 300-500, SO WITH
THIS IN CONSIDERATION AND 5-10% SPC TORNADO THREAT HAVE MENTION OF
ISOLATED TORNADOES IN HWO FOR PORTIONS OF EASTERN OHIO. SHOWERS AND
THUNDERSTORMS WILL COME TO AN END AS THE FRONT PUSHES EAST OF THE
RIDGES NEAR DAWN ON THURSDAY. OVERNIGHT LOWS ARE NEAR A MAV/MET
BLEND, COOLING TO A FEW DEGREES BELOW NORMAL AS COLD AIR ADVECTS
IN BEHIND THE FRONT.
WITH PWATS INCREASING TO AROUND AN INCH (2 STANDARD DEVIATIONS ABOVE
SEASONAL NORMAL) AND 3HR FFG OF 1.0-1.5 INCHES FROM PREVIOUS
RAINFALL ON WEDNESDAY, BELIEVE THERE WILL BE A FLASH FLOOD THREAT
IN LOCALIZED THUNDERSTORMS FOR PORTIONS OF NORTH-CENTRAL WV,
EASTERN OHIO, EXTREME SOUTHWEST PA, AND WESTERN MD. THUS, A FLASH
FLOOD WATCH REMAINS FOR PORTIONS OF THE AREA.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY/...
SREF MODEL OUTPUT SHOWS WINDS CAN STILL GUST TO 35-40 MPH DAYTIME
SATURDAY. COLD POOL STRATOCUMULUS MAY HAVE ENOUGH BREAKS FOR SOME
SUNSHINE BY AFTERNOON. RECENT GFS AND NAM MOS SHOW FORECASTED HIGH
TEMPERATURES TO BE 10 DEGREES COLDER THAN FRIDAY, BUT TO BE NEAR
SEASONABLE.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
BLEND OF RECENT ECMWF AND NAEFS MODEL OUTPUT SHOWS A SECONDARY
CANADIAN COLD FRONT WILL PROVIDE AN ADDITIONAL COLD SHOT FOR LATE
SATURDAY NIGHT AND SUNDAY, WHICH WILL BE ACCOMPANIED BY LAKE
ENHANCED SNOW SHOWERS INTO SUNDAY NIGHT. COLD TEMPERATURES WILL
PERSIST MONDAY WITH PERHAPS LINGERING FLURRIES.
HIGH PRESSURE SHOULD PROMOTE DRY CONDITIONS AND MODERATING
TEMPERATURES TUESDAY INTO THURSDAY, AS SHOWN BY GFS MOS, NAEFS
MEDIAN VALUES, AND OPERATIONAL ECMWF MODEL OUTPUT.
&&
.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
RAIN ASSOCIATED WITH A WARM FRONT WILL OVERSPREAD TERMINALS FROM
SOUTH TO NORTH DURING THE MID TO LATE AFTERNOON HOURS. AT 18Z TAF
ISSUANCE...THERE WAS LITTLE ORGANIZED CONVECTION OCCURRING WITH THE
FRONT...SO HAVE ONLY GONE WITH A CB MENTION AT THIS TIME. A
THUNDERSTORM CANNOT BE RULED OUT WITH THE WARM FRONT. SOME LOW LEVEL
WIND SHEAR COULD OCCUR DURING THIS TIME WITH SURFACE WINDS OUT OF
THE S-SE AND WINDS ALOFT OUT OF THE S-SW...BUT HAVE CHOSEN TO
HIGHLIGHT WIND GUSTS AT THIS TIME. THERE COULD BE A SLIGHT GAP IN
RAINFALL BETWEEN THE WARM FRONT DURING THE LATE AFTERNOON AND THE
COLD FRONT ARRIVING THIS EVENING FROM THE WEST. THE COLD FRONT WILL
BE QUITE STRONG...AND THERE IS THE POSSIBILITY FOR HAIL AND 50KT
WINDS IN THUNDERSTORMS AS THE FRONT PASSES. DID NOT HAVE ENOUGH
CONFIDENCE IN TIMING TO SPECIFICALLY INCLUDE TEMPO TSRA IN TAFS AT
THIS TIME.
ONCE COLD FRONT PASSES BETWEEN 03-06Z...CLOUDS WILL BEGIN TO SCATTER
OUT...BUT GUSTS WILL REMAIN 25-30 KTS OUT OF THE SOUTHWEST.
SUSTAINED WINDS WILL DROP SLIGHTLY OVERNIGHT...BUT BY LATE MORNING
MANY SITES WILL APPROACH WESTERLY 20G30KT...WITH HIGHER VALUES TO
THE NORTH. ANOTHER LINE OF CLOUDS WILL APPROACH...BUT CONDITIONS
WILL REMAIN VFR WITH NO PRECIPITATION.
OUTLOOK...SATURDAY AFTERNOON THROUGH WEDNESDAY...
CONDITIONS WILL REMAIN VFR SATURDAY AFTERNOON INTO SATURDAY EVENING
IN ADVANCE OF AN UPPER LEVEL SYSTEM MOVING ACROSS THE GREAT LAKES.
EXPECT RESTRICTIONS IN SNOW SHOWERS SATURDAY NIGHT INTO SUNDAY
NIGHT. TERMINALS SOUTH OF PITTSBURGH COULD REMAIN UNDER RESTRICTIONS
IN SNOW SHOWERS MONDAY. HIGH PRESSURE WILL BRING VFR CONDITIONS FOR
MONDAY NIGHT THROUGH WEDNESDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR MDZ001.
OH...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR OHZ068-069.
PA...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR PAZ031-073>076.
WV...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR WVZ004-012-021>023-
041.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
201 PM EST FRI MAR 2 2012
.SYNOPSIS...
A STRONG LOW PRESSURE SYSTEM WILL BRING SHOWERS AND THUNDERSTORMS
THIS AFTERNOON WITH STRONG TO SEVERE THUNDERSTORMS POSSIBLE
TONIGHT. IN THE WAKE OF THE FRONT, COLDER AIR WILL MOVE INTO THE
AREA WITH GUSTY WINDS EXPECTED ON SATURDAY AND SNOW SHOWERS
POSSIBLE ON SUNDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AN EARLY AFTERNOON ENHANCED SHORT TERM FORECAST HAS BEEN ISSUED TO
PIN DOWN TIMING ON SHOWERS AND POSSIBLE THUNDERSTORMS EARLY AND
MORE ORGANIZED CONVECTION TONIGHT AS IT CROSSES THE AREA AHEAD OF
A COLD FRONT.
THE LATEST RUC MID-LEVEL ANALYSIS INDICATES A SOUTHWESTERLY FLOW
ACROSS THE UPPER OHIO VALLEY AHEAD OF A CLOSED LOW ACROSS THE
NORTHERN PLAINS. AT THE SURFACE, A 992MB SURFACE LOW IS CENTERED
ACROSS SOUTHERN ILLINOIS WITH A WARM FRONT EXTENDING EASTWARD
ACROSS KENTUCKY AND WEST VIRGINIA.
THIS AFTERNOON...THE WARM FRONT WILL PUSH NORTHEAST TOWARD THE
AREA, WITH ELEVATED INSTABILITY (MUCAPE AROUND 500 J/KG) SLIDING
INTO EASTERN OHIO AND NORTH-CENTRAL WV. THIS WILL ALLOW FOR
SHOWERS WITH THE CHANCE OF THUNDERSTORMS TO PUSH INTO THE AREA.
DESPITE STRONG SHEAR, LIMITED INSTABILITY AND DRY LOW-LEVELS WILL
PREVENT SEVERE THREAT EARLY.
TONIGHT...THE STRENGTHENING SURFACE LOW WILL MOVE INTO THE GREAT
LAKES, SWINGING A COLD FRONT ACROSS THE UPPER OHIO VALLEY. WITH
SBCAPE AROUND 500 J/KG AND A 50KT 850MB LOW-LEVEL JET, 4KM WRF-
NMM SUPPORTS THE POSSIBLE DEVELOPMENT OF A SQUALL LINE JUST AHEAD
OF THE COLD FRONT PUSHING ACROSS THE AREA. THIS WILL BRING THE
PRIMARY THREAT OF DAMAGING WINDS TO THE AREA. THE NAM/SREF ARE
INDICATING 0-1KM SHEAR OF 40KTS AND 0-1 SRH AT 300-500, SO WITH
THIS IN CONSIDERATION AND 5-10% SPC TORNADO THREAT HAVE MENTION OF
ISOLATED TORNADOES IN HWO FOR PORTIONS OF EASTERN OHIO. SHOWERS AND
THUNDERSTORMS WILL COME TO AN END AS THE FRONT PUSHES EAST OF THE
RIDGES NEAR DAWN ON THURSDAY. OVERNIGHT LOWS ARE NEAR A MAV/MET
BLEND, COOLING TO A FEW DEGREES BELOW NORMAL AS COLD AIR ADVECTS
IN BEHIND THE FRONT.
WITH PWATS INCREASING TO AROUND AN INCH (2 STANDARD DEVIATIONS ABOVE
SEASONAL NORMAL) AND 3HR FFG OF 1.0-1.5 INCHES FROM PREVIOUS
RAINFALL ON WEDNESDAY, BELIEVE THERE WILL BE A FLASH FLOOD THREAT
IN LOCALIZED THUNDERSTORMS FOR PORTIONS OF NORTH-CENTRAL WV,
EASTERN OHIO, EXTREME SOUTHWEST PA, AND WESTERN MD. THUS, A FLASH
FLOOD WATCH REMAINS FOR PORTIONS OF THE AREA.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY/...
SREF MODEL OUTPUT SHOWS WINDS CAN STILL GUST TO 35-40 MPH DAYTIME
SATURDAY. COLD POOL STRATOCUMULUS MAY HAVE ENOUGH BREAKS FOR SOME
SUNSHINE BY AFTERNOON. RECENT GFS AND NAM MOS SHOW FORECASTED HIGH
TEMPERATURES TO BE 10 DEGREES COLDER THAN FRIDAY, BUT TO BE NEAR
SEASONABLE.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
BLEND OF RECENT ECMWF AND NAEFS MODEL OUTPUT SHOWS A SECONDARY
CANADIAN COLD FRONT WILL PROVIDE AN ADDITIONAL COLD SHOT FOR LATE
SATURDAY NIGHT AND SUNDAY, WHICH WILL BE ACCOMPANIED BY LAKE
ENHANCED SNOW SHOWERS INTO SUNDAY NIGHT. COLD TEMPERATURES WILL
PERSIST MONDAY WITH PERHAPS LINGERING FLURRIES.
HIGH PRESSURE SHOULD PROMOTE DRY CONDITIONS AND MODERATING
TEMPERATURES TUESDAY INTO THURSDAY, AS SHOWN BY GFS MOS, NAEFS
MEDIAN VALUES, AND OPERATIONAL ECMWF MODEL OUTPUT.
&&
.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
RAIN ASSOCIATED WITH A WARM FRONT WILL OVERSPREAD TERMINALS FROM
SOUTH TO NORTH DURING THE MID TO LATE AFTERNOON HOURS. AT 18Z TAF
ISSUANCE...THERE WAS LITTLE ORGANIZED CONVECTION OCCURRING WITH THE
FRONT...SO HAVE ONLY GONE WITH A CB MENTION AT THIS TIME. A
THUNDERSTORM CANNOT BE RULED OUT WITH THE WARM FRONT. SOME LOW LEVEL
WIND SHEAR COULD OCCUR DURING THIS TIME WITH SURFACE WINDS OUT OF
THE S-SE AND WINDS ALOFT OUT OF THE S-SW...BUT HAVE CHOSEN TO
HIGHLIGHT WIND GUSTS AT THIS TIME. THERE COULD BE A SLIGHT GAP IN
RAINFALL BETWEEN THE WARM FRONT DURING THE LATE AFTERNOON AND THE
COLD FRONT ARRIVING THIS EVENING FROM THE WEST. THE COLD FRONT WILL
BE QUITE STRONG...AND THERE IS THE POSSIBILITY FOR HAIL AND 50KT
WINDS IN THUNDERSTORMS AS THE FRONT PASSES. DID NOT HAVE ENOUGH
CONFIDENCE IN TIMING TO SPECIFICALLY INCLUDE TEMPO TSRA IN TAFS AT
THIS TIME.
ONCE COLD FRONT PASSES BETWEEN 03-06Z...CLOUDS WILL BEGIN TO SCATTER
OUT...BUT GUSTS WILL REMAIN 25-30 KTS OUT OF THE SOUTHWEST.
SUSTAINED WINDS WILL DROP SLIGHTLY OVERNIGHT...BUT BY LATE MORNING
MANY SITES WILL APPROACH WESTERLY 20G30KT...WITH HIGHER VALUES TO
THE NORTH. ANOTHER LINE OF CLOUDS WILL APPROACH...BUT CONDITIONS
WILL REMAIN VFR WITH NO PRECIPITATION.
OUTLOOK...SATURDAY AFTERNOON THROUGH WEDNESDAY...
CONDITIONS WILL REMAIN VFR SATURDAY AFTERNOON INTO SATURDAY EVENING
IN ADVANCE OF AN UPPER LEVEL SYSTEM MOVING ACROSS THE GREAT LAKES.
EXPECT RESTRICTIONS IN SNOW SHOWERS SATURDAY NIGHT INTO SUNDAY
NIGHT. TERMINALS SOUTH OF PITTSBURGH COULD REMAIN UNDER RESTRICTIONS
IN SNOW SHOWERS MONDAY. HIGH PRESSURE WILL BRING VFR CONDITIONS FOR
MONDAY NIGHT THROUGH WEDNESDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR MDZ001.
OH...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR OHZ068-069.
PA...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR PAZ031-073>076.
WV...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR WVZ004-012-021>023-
041.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
159 PM EST FRI MAR 2 2012
.SYNOPSIS...
A STRONG LOW PRESSURE SYSTEM WILL BRING SHOWERS AND THUNDERSTORMS
THIS AFTERNOON WITH STRONG TO SEVERE THUNDERSTORMS POSSIBLE
TONIGHT. IN THE WAKE OF THE FRONT, COLDER AIR WILL MOVE INTO THE
AREA WITH GUSTY WINDS EXPECTED ON SATURDAY AND SNOW SHOWERS
POSSIBLE ON SUNDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AN EARLY AFTERNOON ENHANCED SHORT TERM FORECAST HAS BEEN ISSUED TO
PIN DOWN TIMING ON SHOWERS AND POSSIBLE THUNDERSTORMS EARLY AND
MORE ORGANIZED CONVECTION TONIGHT AS IT CROSSES THE AREA AHEAD OF
A COLD FRONT.
THE LATEST RUC MID-LEVEL ANALYSIS INDICATES A SOUTHWESTERLY FLOW
ACROSS THE UPPER OHIO VALLEY AHEAD OF A CLOSED LOW ACROSS THE
NORTHERN PLAINS. AT THE SURFACE, A 992MB SURFACE LOW IS CENTERED
ACROSS SOUTHERN ILLINOIS WITH A WARM FRONT EXTENDING EASTWARD
ACROSS KENTUCKY AND WEST VIRGINIA.
THIS AFTERNOON...THE WARM FRONT WILL PUSH NORTHEAST TOWARD THE
AREA, WITH ELEVATED INSTABILITY (MUCAPE AROUND 500 J/KG) SLIDING
INTO EASTERN OHIO AND NORTH-CENTRAL WV. THIS WILL ALLOW FOR
SHOWERS WITH THE CHANCE OF THUNDERSTORMS TO PUSH INTO THE AREA.
DESPITE STRONG SHEAR, LIMITED INSTABILITY AND DRY LOW-LEVELS WILL
PREVENT SEVERE THREAT EARLY.
TONIGHT...THE STRENGTHENING SURFACE LOW WILL MOVE INTO THE GREAT
LAKES, SWINGING A COLD FRONT ACROSS THE UPPER OHIO VALLEY. WITH
SBCAPE AROUND 500 J/KG AND A 50KT 850MB LOW-LEVEL JET, 4KM WRF-
NMM SUPPORTS THE POSSIBLE DEVELOPMENT OF A SQUALL LINE JUST AHEAD
OF THE COLD FRONT PUSHING ACROSS THE AREA. THIS WILL BRING THE
PRIMARY THREAT OF DAMAGING WINDS TO THE AREA. THE NAM/SREF ARE
INDICATING 0-1KM SHEAR OF 40KTS AND 0-1 SRH AT 300-500, SO WITH
THIS IN CONSIDERATION AND 5-10% SPC TORNADO THREAT HAVE MENTION OF
ISOLATED TORNADOES IN HWO FOR PORTIONS OF EASTERN OHIO. SHOWERS AND
THUNDERSTORMS WILL COME TO AN END AS THE FRONT PUSHES EAST OF THE
RIDGES NEAR DAWN ON THURSDAY. OVERNIGHT LOWS ARE NEAR A MAV/MET
BLEND, COOLING TO A FEW DEGREES BELOW NORMAL AS COLD AIR ADVECTS
IN BEHIND THE FRONT.
WITH PWATS INCREASING TO AROUND AN INCH (2 STANDARD DEVIATIONS ABOVE
SEASONAL NORMAL) AND 3HR FFG OF 1.0-1.5 INCHES FROM PREVIOUS
RAINFALL ON WEDNESDAY, BELIEVE THERE WILL BE A FLASH FLOOD THREAT
IN LOCALIZED THUNDERSTORMS FOR PORTIONS OF NORTH-CENTRAL WV,
EASTERN OHIO, EXTREME SOUTHWEST PA, AND WESTERN MD. THUS, A FLASH
FLOOD WATCH REMAINS FOR PORTIONS OF THE AREA.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY/...
SREF MODEL OUTPUT SHOWS WINDS CAN STILL GUST TO 35-40 MPH DAYTIME
SATURDAY. COLD POOL STRATOCUMULUS MAY HAVE ENOUGH BREAKS FOR SOME
SUNSHINE BY AFTERNOON. RECENT GFS AND NAM MOS SHOW FORECASTED HIGH
TEMPERATURES TO BE 10 DEGREES COLDER THAN FRIDAY, BUT TO BE NEAR
SEASONABLE.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
BLEND OF RECENT ECMWF AND NAEFS MODEL OUTPUT SHOWS A SECONDARY
CANADIAN COLD FRONT WILL PROVIDE AN ADDITIONAL COLD SHOT FOR LATE
SATURDAY NIGHT AND SUNDAY, WHICH WILL BE ACCOMPANIED BY LAKE
ENHANCED SNOW SHOWERS INTO SUNDAY NIGHT. COLD TEMPERATURES WILL
PERSIST MONDAY WITH PERHAPS LINGERING FLURRIES.
HIGH PRESSURE SHOULD PROMOTE DRY CONDITIONS AND MODERATING
TEMPERATURES TUESDAY INTO THURSDAY, AS SHOWN BY GFS MOS, NAEFS
MEDIAN VALUES, AND OPERATIONAL ECMWF MODEL OUTPUT.
&&
.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
RAIN ASSOCIATED WITH A WARM FRONT WILL OVERSPREAD TERMINALS FROM
SOUTH TO NORTH DURING THE MID TO LATE AFTERNOON HOURS. AT 18Z TAF
ISSUANCE...THERE WAS LITTLE ORGANIZED CONVECTION OCCURRING WITH THE
FRONT...SO HAVE ONLY GONE WITH A CB MENTION AT THIS TIME. A
THUNDERSTORM CANNOT BE RULED OUT WITH THE WARM FRONT. SOME LOW LEVEL
WIND SHEAR COULD OCCUR DURING THIS TIME WITH SURFACE WINDS OUT OF
THE S-SE AND WINDS ALOFT OUT OF THE S-SW...BUT HAVE CHOSEN TO
HIGHLIGHT WIND GUSTS AT THIS TIME. THERE COULD BE A SLIGHT GAP IN
RAINFALL BETWEEN THE WARM FRONT DURING THE LATE AFTERNOON AND THE
COLD FRONT ARRIVING THIS EVENING FROM THE WEST. THE COLD FRONT WILL
BE QUITE STRONG...AND THERE IS THE POSSIBILITY FOR HAIL AND 50KT
WINDS IN THUNDERSTORMS AS THE FRONT PASSES. DID NOT HAVE ENOUGH
CONFIDENCE IN TIMING TO SPECIFICALLY INCLUDE TEMPO TSRA IN TAFS AT
THIS TIME.
ONCE COLD FRONT PASSES BETWEEN 03-06Z...CLOUDS WILL BEGIN TO SCATTER
OUT...BUT GUSTS WILL REMAIN 25-30 KTS OUT OF THE SOUTHWEST.
SUSTAINED WINDS WILL DROP SLIGHTLY OVERNIGHT...BUT BY LATE MORNING
MANY SITES WILL APPROACH WESTERLY 20G30KT...WITH HIGHER VALUES TO
THE NORTH. ANOTHER LINE OF CLOUDS WILL APPROACH...BUT CONDITIONS
WILL REMAIN VFR WITH NO PRECIPITATION.
OUTLOOK...SATURDAY AFTERNOON THROUGH WEDNESDAY...
CONDITIONS WILL REMAIN VFR SATURDAY AFTERNOON INTO SATURDAY EVENING
IN ADVANCE OF AN UPPER LEVEL SYSTEM MOVING ACROSS THE GREAT LAKES.
EXPECT RESTRICTIONS IN SNOW SHOWERS SATURDAY NIGHT INTO SUNDAY
NIGHT. TERMINALS SOUTH OF PITTSBURGH COULD REMAIN UNDER RESTRICTIONS
IN SNOW SHOWERS MONDAY. HIGH PRESSURE WILL BRING VFR CONDITIONS FOR
MONDAY NIGHT THROUGH WEDNESDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR MDZ001.
OH...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR OHZ068-069.
PA...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR PAZ031-073>076.
WV...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR WVZ004-012-021>023-
041.
&&
$$
SYNOPSIS...WOODRUM
NEAR TERM...WOODRUM
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1106 AM EST FRI MAR 2 2012
.SYNOPSIS...
A STRONG LOW PRESSURE SYSTEM WILL BRING SHOWERS AND THE
CHANCE OF SEVERE THUNDERSTORMS LATE THIS AFTERNOON INTO THE
EVENING. IN THE WAKE OF THE FRONT, COLDER AIR WILL MOVE INTO THE
AREA WITH GUSTY WINDS EXPECTED ON SATURDAY AND SNOW SHOWERS
POSSIBLE ON SUNDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AN ENHANCED SHORT TERM FORECAST UPDATE HAS BEEN ISSUED TO ADD
THUNDER AND INCREASE THE POPS TO BEGIN THE FORECAST.
THE LATEST RUC MID-LEVEL ANALYSIS INDICATES A SOUTHWESTERLY FLOW
ACROSS THE UPPER OHIO VALLEY AHEAD OF A CLOSED LOW ACROSS THE
NORTHERN PLAINS. AT THE SURFACE, A 994MB SURFACE LOW IS LOCATED
ACROSS THE MISSOURI VALLEY WITH A WARM FRONT EXTENDING EASTWARD
ACROSS KENTUCKY. ELEVATED INSTABILITY HAS ALLOWED FOR CONVECTION TO
INITIATE NORTHWARD OF THE WARM FRONT ACROSS THE OHIO VALLEY.
THIS AFTERNOON...THE WARM FRONT WILL PUSH NORTHEAST TOWARD THE
AREA, WITH ELEVATED INSTABILITY (MUCAPE AROUND 500 J/KG) SLIDING
INTO EASTERN OHIO AND NORTH-CENTRAL WV. THIS WILL ALLOW FOR
SHOWERS WITH SCATTERED THUNDERSTORMS TO PUSH INTO THE AREA.
DESPITE STRONG SHEAR, BELIEVE LIMITED INSTABILITY WILL BE A
LIMITING FACTOR AND PREVENT THE SEVERE THREAT INITIALLY.
LATER THIS AFTERNOON INTO THE EVENING, BELIEVE THE SEVERE THREAT
WILL BEGIN IN EASTERN OHIO WITH BEST PUSH OF WARM AIR ADVECTION AS
THE WARM FRONT MOVES INTO THE AREA. AT THIS POINT, FORCING AND
STRONG SHEAR WILL MAY ALLOW FOR A FEW STRONG TO SEVERE
THUNDERSTORMS WITH A THREAT OF LARGE HAIL AND DAMAGING WINDS. THE
NAM/SREF ARE INDICATING 0-1KM SHEAR OF 40KTS AND 0-1SRH AT
300-500, SO WITH THIS IN CONSIDERATION AND 5% SPC TORNADO THREAT
HAVE ADDED MENTION OF ISOLATED TORNADOES INTO PORTIONS OF EASTERN
OHIO.
IN ADDITION, WITH PWATS INCREASING TO AROUND AN INCH (2SDS ABOVE
SEASONAL NORMAL AND 3HR FFG OF 1.0-1.5 INCHES FROM PREVIOUS
RAINFALL ON WEDNESDAY, BELIEVE THERE WILL BE A FLASH FLOOD THREAT
IN LOCALIZED THUNDERSTORMS FOR PORTIONS OF NORTH-CENTRAL WV,
EASTERN OHIO, EXTREME SOUTHWEST PA, AND WESTERN MD. THUS, A FLASH
FLOOD WATCH HAS BEEN ISSUED FOR PORTIONS THIS AREA.
TONIGHT...A STRENGTHENING SURFACE LOW WILL MOVE INTO THE GREAT
LAKES, SWINGING A COLD FRONT ACROSS THE UPPER OHIO VALLEY. WITH
SBCAPE AROUND 500 J/KG AND A 50KT 850MB LOW-LEVEL JET, 4KM WRF-
NMM SUPPORTS THE POSSIBLE DEVELOPMENT OF A SQUALL LINE JUST AHEAD
OF THE COLD FRONT PUSHING ACROSS THE AREA. THIS WILL BRING THE
PRIMARY THREAT OF DAMAGING WINDS TO THE AREA. SHOWERS AND
THUNDERSTORMS WILL COME TO AN END AS THE FRONT PUSHES EAST OF THE
RIDGES NEAR DAWN ON THURSDAY. OVERNIGHT LOWS ARE NEAR A MAV/MET
BLEND, COOLING TO A FEW DEGREES BELOW NORMAL AS COLD AIR ADVECTS
IN BEHIND THE FRONT.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY/...
SREF MODEL OUTPUT SHOWS WINDS CAN STILL GUST TO 35-40 MPH DAYTIME
SATURDAY. COLD POOL STRATOCUMULUS MAY HAVE ENOUGH BREAKS FOR SOME
SUNSHINE BY AFTERNOON. RECENT GFS AND NAM MOS SHOW FORECASTED HIGH
TEMPERATURES TO BE 10 DEGREES COLDER THAN FRIDAY, BUT TO BE NEAR
SEASONABLE.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
BLEND OF RECENT ECMWF AND NAEFS MODEL OUTPUT SHOWS A SECONDARY
CANADIAN COLD FRONT WILL PROVIDE AN ADDITIONAL COLD SHOT FOR LATE
SATURDAY NIGHT AND SUNDAY, WHICH WILL BE ACCOMPANIED BY LAKE
ENHANCED SNOW SHOWERS INTO SUNDAY NIGHT. COLD TEMPERATURES WILL
PERSIST MONDAY WITH PERHAPS LINGERING FLURRIES.
HIGH PRESSURE SHOULD PROMOTE DRY CONDITIONS AND MODERATING
TEMPERATURES TUESDAY INTO THURSDAY, AS SHOWN BY GFS MOS, NAEFS
MEDIAN VALUES, AND OPERATIONAL ECMWF MODEL OUTPUT.
&&
.AVIATION /15Z FRIDAY THROUGH TUESDAY/...
EXPECT VFR THROUGH 20Z ACROSS THE UPPER OHIO VALLEY.
WITH THE STRONG LOW PRESSURE CENTER MOVING FROM OKLAHOMA THIS
MORNING NORTHEASTWARD TO MICHIGAN TONIGHT, EXPECT A WARM FRONTAL
MVFR RAIN BAND TO PASS THROUGH THE UPPER OHIO VALLEY 20Z-02Z,
FOLLOWED BY A COLD FRONTAL BAND OF MVFR SHOWERS AND SCATTERED
THUNDERSTORMS 01Z-05Z. SHORT IFR PERIODS WILL ALSO BE POSSIBLE.
PER SPC GUIDANCE, THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS
WITH THE MAIN AVIATION HAZARD STRONG WIND GUSTS AND SECONDARY HAZARD
HAIL MAINLY ALOFT.
THE POST COLD FRONTAL COOL DOWN WILL PROVIDE WIND GUSTS TO 30-35 KTS
LATE TONIGHT. THE PERIOD WILL BE DRY, BUT MAY STILL PROVIDE MVFR
STRATOCUMULUS CEILINGS.
OUTLOOK...SATURDAY THROUGH TUESDAY...
DURING DAYTIME SATURDAY, WINDS CAN STILL GUST OVER 30 KTS. REMAINING
STRATOCUMULUS CEILINGS SHOULD LIFT TO VFR LEVELS. A SECONDARY
CANADIAN COLD FRONT WILL PROVIDE SNOW SHOWERS AND RESTRICTIONS LATE
SATURDAY NIGHT AND SUNDAY. ENSUING MIDWEST HIGH PRESSURE WILL
RESTORE VFR FOR MONDAY AND TUESDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR MDZ001.
OH...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR OHZ068-069.
PA...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR PAZ031-073>076.
WV...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR WVZ004-012-021>023-
041.
&&
$$
SYNOPSIS...WOODRUM
NEAR TERM...WOODRUM
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
449 PM EST FRI MAR 2 2012
.SYNOPSIS...
ISSUED AT 445 PM EST FRI MAR 2 2012
LOW PRESSURE WILL RAPIDLY INTENSIFY TONIGHT AS IT PASSES THROUGH
LOWER MICHIGAN. STRONG... POSSIBLY DAMAGING... WINDS ARE EXPECTED
AS THE LOW PASSES BY.
ALSO ACCOMPANYING THE LOW PRESSURE SYSTEM WILL BE AN AREA OF
HEAVY SNOW ACROSS NORTHERN LOWER MICHIGAN. ELSEWHERE RAIN AND
SCATTERED THUNDERSTORMS ARE EXPECTED.
SCATTERED SNOW SHOWERS WILL LINGER SATURDAY AND SUNDAY IN THE
COLD AIR ON THE BACK SIDE OF THE DEPARTING SYSTEM.
A WARM UP IS ON THE WAY FOR THE AREA FOR THE FIRST HALF OF THE
WORK WEEK. 40S TO 50S WILL BE POSSIBLE BY WEDNESDAY.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 445 PM EST FRI MAR 2 2012
SFC LOW TO TRACK ACROSS KALAMAZOO TO SAGINAW BAY THIS EVENING
WHILE RAPIDLY DEEPENING. LATEST MSAS SHOWS IT AT PRESENTLY 990MB
IN WRN INDIANA AND THE HRR RUC HAS IT 970MB AT 07Z OVER SAGINAW
BAY. AS THE LOW PASSES BY LATER THIS EVENING LOOK FOR WIND GUSTS
APPROACHING OR EXCEEDING WARNING CRITERIA OF 50 KNOTS. THIS IS
SUPPORTED IN FCST SNDGS AND HRR WIND GUST PROGS... WITH BEST
THREAT OVER THE SRN FCST AREA. NOT AS CERTAIN NORTH OF ST JOHNS.
BEST WINDOW FOR SVR GUSTS IS ROUGHLY 04Z-08Z... BUT WILL HAVE
BUFFER ON EITHER SIDE FOR THE WARNING TIME.
AS FAR AS THE HEAVY SNOW THREAT... DID NOT STRAY TOO MUCH FROM
PREVIOUS FCST. CONVECTION/LIGHTNING STRIKES NOW BEING OBSERVED
ACROSS NRN IL IN THE SRN EDGE OF DEVELOPING DEFORMATION
ZONE/TROWAL. THIS FEATURE WILL ONLY INTENSIFY THIS EVENING... THEN
IT/S JUST A MATTER OF CHANGING PCPN OVER TO SNOW IN THE WARNING
AREA. IT LOOKS PRETTY WARM THROUGH 00Z... THEN RAPID DYNAMICAL
COOLING SHOULD FORCE CHANGEOVER TO HEAVY SNOW WITH ONE TO TWO INCH
PER HOUR RATES STILL LIKELY TONIGHT.
BECAUSE OF THE MARGINAL SFC TEMPS IN THE MID 30S ACROSS THE
WARNING AREA... ELEVATION WILL PROBABLY PLAY A CRITICAL ROLE IN
WHEN RAIN CHANGES TO SNOW AND ALSO IN STORM TOTAL SNOW
ACCUMULATION. HAVE ADDED IN MECOSTA COUNTY INTO THE WARNING AS
HIGHER ELEVATIONS THERE MAY RESULT IN AMOUNTS APPROACHING SIX
INCHES. HOWEVER EVEN WHERE ACCUMS DO NOT REACH SIX INCHES THE
WARNING IS PROBABLY STILL WELL JUSTIFIED DUE TO THE COMBO OF THE
HIGH WINDS AND THE SNOW.
HEAVY SYNOPTIC SNOW IN THE DEFORMATION ZONE SHOULD BE WINDING DOWN
TOWARD 12Z SAT... WITH A TRANSITION TO LAKE EFFECT/ENHANCED SNOWS.
ANOTHER 2 TO 4 INCHES IS POSSIBLE ON SATURDAY IN THE WARNING
AREA... AND ALSO FARTHER SOUTH INCLUDING THE GRR/BIV AREAS. AFTER
THE HIGH WIND WARNING EXPIRES... A WINTER WEATHER ADVISORY MAY BE
NEEDED SATURDAY FOR KENT/OTTAWA SOUTH... WHILE THE WARNING
CONTINUES IN THE NORTH.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 213 PM EST FRI MAR 2 2012
THERE ARE TWO SYSTEMS WE ARE WATCHING IN THE LONG TERM PERIOD. THE
FIRST IS THE LAKE ENHANCED SNOW SHOWERS WITH THE ARCTIC FRONT
COMING THROUGH EARLY SUNDAY MORNING THEN THE SYSTEM IN THE
WEDNESDAY TIME FRAME.
THERE IS A TRAILING NORTHERN STREAM SYSTEM THAT ROTATES ACROSS
LOWER MICHIGAN SUNDAY NIGHT ON THE NORTHERN STREAM. THIS BRINGS TO
COLDEST AIR THIS AREA HAS SEEN SINCE THE AROUND THE 12TH OF
FEBRUARY. HIGH TEMPERATURES WILL BE BELOW FREEZING SUNDAY ACROSS
JUST ABOUT ALL OF THE CWA. WITH THAT COLD AIR COMING IN I EXPECTED
ENHANCED LAKE EFFECT SNOW SHOWERS AS THERE IS GOOD UPPER AIR
SUPPORT AND DECENT LOW LEVEL WIND CONVERGENCE ON THE FRONT. SO I
HAVE HIGH POPS SUNDAY NIGHT WEST OF US-131. SNOWFALL SHOULD BE
LIMITED AS THE SNOW WILL MOSTLY HAPPEN AS THE FRONT DROPS SOUTH.
ONCE THE FRONT IS THROUGH WINDS BECOME NORTH DURING THE DAY SUNDAY
SO SNOW SHOWERS WILL MOSTLY BE NEAR THE LAKE SHORE. SUNDAY NIGHT
THE HIGH MOVES IN AND ANY SNOW SHOWERS SHOULD DIMINISH. THE UPPER
LEVEL JET CROSSING SOUTHWEST LOWER MICHIGAN EARLY MONDAY WILL
CAUSE THE INVERSION HEIGHT TO CRASH TOO... FARTHER LIMITING THE
POTENTIAL FOR SNOW SHOWERS.
HIGH PRESSURE RULES MONDAY DURING THE DAY INTO TUESDAY. THEN THE
NEXT SYSTEM DURING THE WEDNESDAY TO THURSDAY TIME FRAME. THERE ARE
BIG DIFFERENCES BETWEEN THE GFS AND ECMWF AS THE ECMWF HAS A MUCH
LARGER UPPER RIDGE OVER THE WEST COAST... CAUSING A MUCH DEEPER
TROUGH OVER THE CENTRAL UNITED STATES. THE ECMWF BRINGS EVEN
COLDER AIR IN BEHIND THAT SYSTEM THURSDAY INTO FRIDAY THAN THIS
WEEKEND. WITH THE GFS BEING MUCH FLATTER... NOT MUCH COLD AIR
FOLLOWS. GIVEN THE VARIABILITY ON THE MODELS AND THAT EVEN THE
ECMWF HAS NOT BEEN VERY CONSISTENT WITH THIS I WENT HALF WAY
BETWEEN THE TOO MODELS. FOR NOW THROUGH BOTH SUGGEST EVERY WARM
WEATHER WITH SHOWERS WEDNESDAY AHEAD OF THE COLD FRONT. THE ISSUE
STARTS THURSDAY ONCE THE COLD AIR COMES IN. WE WILL HAVE TO WATCH
THIS FOR ANOTHER POSSIBLE WINTER WEATHER EVENT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 100 PM EST FRI MAR 2 2012
THE SEVERE THREAT HAS SHIFTED A BIT SOUTH OF WHERE IT WAS EARLY
THIS MORNING. THERE IS NOW A HIGHER CHANCE THAT SVR STORMS WILL
REMAIN SOUTH OF THE TAF SITES. THAT SAID...STORMS WILL BE MOST
LIKELY OVER SRN LWR AND MAY CLIP THE SRN TAF SITES. LESSER CHANCES
NORTH. A WIDE SWING IN WEATHER EXPECTED OVER THE NEXT 24 HRS AS
SHOWERS WILL TRANSITION TO SNOW. MODERATE TO HEAVY SNOW IS
EXPECTED AT KMKG THIS EVENING AND LIGHT SNOW GRADUALLY SPREADING
OVER THE REST OF THE TAF SITES BY 06Z OR SO. EAST WINDS WILL
BECOME WNW WITH TIME AND BE VERY WINDY WITH GUSTS TO AROUND 40
KNOTS TONIGHT.
&&
.MARINE...
ISSUED AT 445 PM EST FRI MAR 2 2012
UPGRADED THE GALE WARNING TO A STORM WARNING FOR TONIGHT AS
INTENSE LOW GOES BY. GALES STILL POSSIBLE EARLY SATURDAY BEFORE
A GRADUAL DIMINISHING TREND THROUGH SATURDAY NIGHT AND SUNDAY.
&&
.HYDROLOGY...
ISSUED AT 445 PM EST FRI MAR 2 2012
RIVER LEVELS ARE HIGH DUE TO RECENT RAINS... AND UP TO ANOTHER
INCH OF RAIN MAY FALL TONIGHT. LOCALLY HIGHER AMOUNTS ALSO
POSSIBLE. AT THIS TIME... EVEN WITH FUTURE QPF FACTORED IN... NO
SITES ARE FORECAST TO REACH OR EXCEED FLOOD STAGE. SEVERAL SITES
HOWEVER ARE IN FLOOD ADVISORIES... INCLUDING... GRAND RIVER AT
IONIA... PORTAGE RIVER NEAR VICKSBURG... GRAND RIVER AT JACKSON...
SYCAMORE CREEK AT HOLT... MAPLE RIVER AT MAPLE RAPIDS... AND
THORNAPPLE RIVER ABOVE HASTINGS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...HIGH WIND WARNING FROM 9 PM THIS EVENING TO 7 AM EST SATURDAY
FOR MIZ046-051-052-056>059-064>067-071>074.
WINTER STORM WARNING FROM 7 PM THIS EVENING TO 1 PM EST SATURDAY
FOR MIZ037>040-043>045-050.
LM...STORM WARNING FROM 9 PM THIS EVENING TO 7 AM EST SATURDAY FOR
LMZ844>849.
&&
$$
SYNOPSIS...MEADE
SHORT TERM...MEADE
LONG TERM....WDM
AVIATION...93
MARINE...MEADE
HYDROLOGY...MEADE
AREA FORECAST DISCUSSION
NWS SPRINGFIELD MO
1152 AM CST FRI MAR 2 2012
...UPDATE TO AVIATION...
.UPDATE...
/ISSUED 615 AM CST FRI MAR 2 2012/
SURFACE LOW WAS TRACKING NORTHEAST ACROSS SOUTHERN MISSOURI EARLY
THIS MORNING AND WAS LOCATED NEAR SPRINGFIELD AT 12Z (7 AM).
SCATTERED CONVECTION CONTINUED ALONG AND JUST BEHIND THE ASSOCIATED
FRONT. SEVERE STORMS THAT PRODUCED LARGE HAIL ACROSS PORTIONS OF
CENTRAL MISSOURI EARLIER THIS MORNING HAD TRACKED EAST OF THE
AREA ON THE NOSE OF THE LOW LEVEL JET.
MOST UNSTABLE CAPES AROUND 1000 J/KG AND OVER 70 KTS OF DEEP
LAYERED SHEAR WILL SUPPORT THE POTENTIAL FOR ADDITIONAL SEVERE
STORMS AHEAD OF THE FRONT THIS MORNING. STORMS EARLY ON WILL
CONTINUE TO BE PRIMARILY ELEVATED IN NATURE BUT THERE IS CONCERN
THAT STORMS WILL BECOME ROOTED NEAR OR AT THE SURFACE ACROSS SOUTH
CENTRAL MISSOURI AS THE MORNING PROGRESSES. LATEST RUC ANALYSIS
DEPICTS DECREASING MIXED LAYER INHIBITION ACROSS FAR SOUTH CENTRAL
MISSOURI. THIS TREND WILL LIKELY CONTINUE AS RICHER LOW LEVEL
MOISTURE STREAMS NORTH. IF STORMS BECOME SURFACE BASED THE RISK
FOR DAMAGING WINDS AND ISOLATED TORNADOES WOULD INCREASE.
FOSTER
&&
.DISCUSSION...
/ISSUED 245 AM CST FRI MAR 2 2012/
THUNDERSTORMS WERE RAPIDLY DEVELOPING EARLY THIS MORNING ACROSS
PORTIONS OF SOUTHWEST AND CENTRAL MISSOURI NORTHEAST OF A SURFACE
LOW PRESSURE SYSTEM LOCATED IN NORTHEAST OKLAHOMA. STRONG WARM AIR
AND MOISTURE ADVECTION EAST OF THIS LOW OVER TOP THE BOUNDARY
LAYER WAS RESULTING RAPID DESTABILIZATION. MOST UNSTABLE CAPE OF
AROUND 1000 TO NEAR 2000 J/KG WAS NOSING INTO SOUTHERN MISSOURI.
THIS INSTABILITY COUPLED WITH STRONG DEEP LAYERED SHEAR WILL
SUPPORT STRONG TO SEVERE CONVECTION EARLY THIS MORNING. CONVECTIVE
MODE WILL BE ELEVATED SUPERCELLS WITH LARGE HAIL THE PRIMARY RISK. THIS
ACTIVITY WILL RACE EASTWARD.
WILL HAVE TO CLOSELY MONITOR CONVECTIVE TRENDS FARTHER SOUTH ALONG
THE ARKANSAS BORDER CLOSER TO THE SURFACE WARM FRONT. CONVECTION
COULD BECOME ROOTED NEAR THE SURFACE IN THIS AREA RESULTING IN A
GREATER RISK FOR DAMAGING WINDS
EXPECT ACTIVITY TO MOVE EAST OF THE AREA BY EARLY AFTERNOON IF NOT
EARLIER. COLDER AIR ADVECTION WILL DEVELOP DURING THE AFTERNOON AS
THE SURFACE LOW MOVES OFF TO THE EAST RESULTING STEADY IF NOT
FALLING TEMPERATURES. A CHILLY NIGHT IS IN STORE TONIGHT WITH MANY
AREAS NEAR THE FREEZING MARK. BELOW NORMAL TEMPERATURES ARE IN
STORE FOR SATURDAY AS AN UPPER TROUGH SWINGS ACROSS THE REGION.
MODERATING TEMPERATURES WILL BEGIN SUNDAY WITH A MORE SUBSTANTIAL
WARMING TREND BEGINNING MONDAY AS A SOUTHERLY FLOW DEVELOPS. WILL
HAVE TO MONITOR FIRE WEATHER CONDITIONS MONDAY GIVEN GUSTY
SOUTHERLY WINDS AND EXISTING DRY AIR MASS.
PRECIPITATION CHANCES RETURN BY THE MIDDLE OF NEXT WEEK AS THE
NEXT UPPER TROUGH APPROACHES.
&&
.AVIATION...
FOR THE 18Z TAFS...FLIGHT CONDITIONS WILL CONTINUE TO IMPROVE
THROUGH THIS AFTERNOON. SURFACE WINDS WILL REMAIN GUSTY FROM THE
NORTHWEST INTO LATE AFTERNOON HOURS HOWEVER. EXPECT VFR
CONDITIONS AFTER 19Z FOR ALL TERMINALS.
HATCH
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GLASGOW MT
221 PM MST FRI MAR 2 2012
.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH SUNDAY...
SYNOPTIC SET UP... A TROUGH IS TRANSITIONING FROM THE NORTHERN
PLAINS INTO THE GREAT LAKES. COLDEST AIR OF THE NORTHERN HEMISPHERE
SITS OVER THE NORTHERN HUDSON BAY. TO THE WEST A RIDGE EXTENDS
FROM UP THE COAST OF CALIFORNIA INTO CENTRAL BRITISH COLUMBIA.
ANOTHER LONG WAVE TROUGH IS MOVING OUT OF THE BEARING SEA INTO THE
GULF OF ALASKA.
THIS AFTERNOON AND EVENING... MONTANA WILL BE WEDGED IN NORTHWEST
FLOW BETWEEN THE EXITING TROUGH AND ENTERING RIDGE WHICH WILL
PROVIDE OCCASIONAL INSTABILITY. ACROSS THE SOUTHWEST SECTIONS OF
THE CWA THE HRRR MODEL ALONG WITH BOTH VERSIONS OF THE WRF ARE
POINTING TOWARDS AFTERNOON AND LATE EVENING INSTABILITY SHOWERS.
HAVE THROWN UP LIMITED POPS FOR THESE EVENTS BEING THAT THEY ARE A
BIT ON THE CHAOTIC SIDE. HOWEVER... AFTERNOON SHOWERS SEEM MORE
LIKELY DUE TO SIMILAR ACTIVITY TO YESTERDAY AFTERNOON WITH
CLEARING SKIES AND NO SNOW COVER.
SATURDAY MORNING THROUGH SUNDAY... UPPER LEVEL RIDGE TO THE WEST
WILL CONTINUE TO FILTER INTO THE REGION AND ASSERT INCREASING
DOMINANCE. 850 MB TEMPERATURES ARE ANTICIPATED TO RISE FROM RANGE
OF -9*C TO -2*C UP INTO THE POSITIVE SINGLE DIGITS CELCIUS. SKIES
WILL BE BE MOSTLY CLOUDY INITIALLY BUT SHOULD BE DECREASING OVER
THE NEXT FEW DAYS. A LEE SIDE MOUNTAIN TROUGH WILL SET UP AT THE
SURFACE TONIGHT AND BEGIN WAFFLING BACK AND FORTH ACROSS THE CWA
THROUGH SUNDAY. THIS WILL HELP TO TRIGGER INSTABILITY SHOWERS EACH
AFTERNOON AND EVENING. ON SUNDAY THE TROUGH WILL WANDER FAR ENOUGH
EASTWARD LATE IN THE DAY DUE TO DOWNSLOPE WARMING THAT IT WILL
EXIT THE AREA BRINGING TOTALLY DRY CONDITIONS. GAH
.LONG TERM...SUNDAY NIGHT THROUGH FRIDAY...
FAIR CONFIDENCE FOR THE EARLY PERIODS OF THE EXTENDED BUT DROPS
CONSIDERABLY BY MIDWEEK...WITH LOW CONFIDENCE INTO NEXT WEEKEND.
UPPER RIDGE OVER THE REGION MONDAY BREAKS DOWN AS AN UPPER TROF
PUSHES THROUGH THE PACIFIC NORTHWEST. STILL SOME QUESTIONS
REGARDING THIS TROF AND HOW MUCH IT DIGS SOUTHWEST AS IT PUSHES
THROUGH THE GREAT BASIN. STILL EXPECT SOME SNOW AS A STRONG COLD
FRONT MOVES ACROSS THE STATE MONDAY NIGHT/TUESDAY BUT HEAVIEST
AMOUNTS CURRENTLY EXPECTED IN SOUTHWEST MONTANA. REMAINDER OF THE
FORECAST TRENDED TOWARD CLIMO WHICH IS SIMILAR TO A MODEL BLEND
DUE TO THE SIGNIFICANT MODEL DIFFERENCES. EBERT
PREVIOUS LONG TERM DISCUSSION...THE EXTENDED FORECAST BEGINS WITH
UPPER RIDGING IN PLACE OVER THE REGION. THE ATMOSPHERE WARMS QUITE
NICELY ACROSS CENTRAL AND EASTERN MONTANA. LONG RANGE MODELS AGREE
ON THIS AND HAVE SHOWN THIS TREND FOR THE PAST FEW DAYS FOR ABOVE
NORMAL CONFIDENCE FOR SUNDAY NIGHT THROUGH WEDNESDAY MORNING. THEN
THE EC AND GFS HEAD OFF IN DIFFERENT DIRECTIONS...THEREFORE AFTER
WEDNESDAY MORNING THE FORECAST CONFIDENCE FACTOR DROPS OFF
SIGNIFICANTLY. GOING TO SIDE MORE WITH THE GFS FAMILY OVER THE EC.
BOTH THE GFS AND EC MODELS DO SHOW SOME ODDITIES FOR THIS TIME OF
YEAR. THE OVERALL AMOUNT OF CUT OFF LOWS IN EACH MODEL AROUND THE
NORTHERN HEMISPHERE LEADS TO A VERY COMPLICATED PATTERN FOR LARGE
SCALE MODELS TO GIVE A GOOD SOLUTION THAT FAR OUT. THE ENSEMBLES
DO NOT FAVOR EITHER MODEL OR GIVE AN IDEA OF WHICH DIRECTION TO
TAKE THE FORECAST THEREFORE OPTED FOR PERSISTENCE FROM WEDNESDAY
AND BEYOND.
MONDAY WILL HIGHLIGHT ABOVE NORMAL TEMPERATURES AND SPRING LIKE
WEATHER FOR THE REGION. TUESDAY A COLD FRONT WILL PUSH THROUGH
NORTHEAST MONTANA... THE FRONTAL TIMING HAS SPED UP THEREFORE DID
TAKE TEMPERATURES DOWN A FEW DEGREES FOR THE EARLIER FRONTAL
PASSAGE. WEDNESDAY AND BEYOND... SLOW WARMING TREND TO KEEP WITH
THE PERSISTENCE TREND. PROTON
&&
.AVIATION...
GENERALLY EXPECT VFR CONDITIONS ALTHOUGH A FEW SNOW SHOWERS MAY
MOVE ACROSS THE REGION TONIGHT AND SATURDAY. FLIGHT CONDITIONS
WITH THE SNOW SHOWERS COULD DROP TO MVFR OR POSSIBLY IFR LEVELS.
RAE
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS GLASGOW MT
931 AM MST FRI MAR 2 2012
.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH SUNDAY...
LOW PRESSURE CONTINUES TO MOVE EAST OVER THE NORTHERN PLAINS AND
LEAVE MONTANA BEHIND. HOWEVER THE PRESSURE GRADIENT BEHIND THIS STORM
SYSTEM HAS LEFT OVER STRONG ENOUGH WINDS TO CREATE GUSTS AND SOME
DRIFTING WITH VISIBILITY PROBLEMS THROUGH THE MORNING HOURS. HIGH
PRESSURE SITS OFF TO THE NORTH AND WEST AND WILL BEGIN MOVING INTO
THE REGION DURING THE AFTERNOON HOURS. THIS SHOULD REDUCE WINDS
OVER ALL. A STALLED BOUNDARY THAT IS FALLING APART IS ALSO
HELPING TO PROVIDE ENOUGH OF A FOCAL MECHANISM TO CONTINUE
PRODUCING LIGHT SNOW ACROSS SOUTHEASTERN SECTIONS OF THE CWA.
ACROSS THE SOUTHWEST SECTIONS OF THE CWA THE HRRR MODEL ALONG WITH
BOTH VERSIONS OF THE WRF ARE POINTING TOWARDS AFTERNOON AND LATE
EVENING INSTABILITY SHOWERS. HAVE THROWN UP LIMITED POPS FOR THESE
EVENTS BEING THAT THEY ARE A BIT ON THE CHAOTIC SIDE. HOWEVER...
AFTERNOON SHOWERS SEEM MORE LIKELY DUE TO SIMILAR ACTIVITY TO
YESTERDAY AFTERNOON WITH CLEARING SKIES AND NO SNOW COVER. GAH
PREVIOUS SHORT TERM DISCUSSION...
WATER VAPOR IMAGERY AND 500 MB HEIGHT FIELD REVEALS A VERY ACTIVE
WEATHER PATTERN ACROSS THE CONUS. A BROAD LARGE SCALE UPPER TROUGH
OVER THE ROCKY MOUNTAIN AND CENTRAL STATES IS SPREADING SCATTERED
SNOW SHOWERS ACROSS THOSE AREAS. ON THE OTHER SIDE...EASTWARD
AHEAD OF THE TROUGH...THE STAGE IS SET FOR A MODERATE RISK OF
SEVERE THUNDERSTORMS AND TORNADOES ACROSS THE OHIO RIVER VALLEY
AND SOUTHWARD THROUGH KENTUCKY AND TENNESSEE. EVEN NOW...A FEW
THUNDERSTORMS ARE TRYING TO BREAK OUT IN THAT GENERAL REGION. AN
UPPER LEVEL RIDGE IS MOVING NEAR THE WEST COAST.
FORECAST CHALLENGES INCLUDE THE CURRENT WINTER WEATHER ADVISORY
OVER OUR NORTHEAST ZONES.
EVEN THOUGH RADAR RETURNS ARE QUITE LIGHT AND BARELY MODERATE AT
TIMES...THERE SEEMS TO BE ENOUGH OBSERVATIONAL SUPPORT FOR
CONTINUING THE WINTER WEATHER ADVISORY THROUGH THE MORNING HOURS.
DIMINISHING RADAR RETURNS FURTHER AWAY FROM THE RADAR ARE MOST
LIKELY REPRESENTATIVE OF THE RADAR BEAM CUTTING ABOVE THE SNOW
FALLING AT THE LOWEST LEVELS. CASE IN POINT...WILLISTON IS AT THE
EDGE OF VERY LIGHT RETURNS OR NONE AT ALL...YET THE OBSERVATION
STILL RECORDS SNOW FALL. WINDS FROM THE NORTHWEST ARE HOLDING
QUITE STEADY FROM 15G25 KT TO 20G30 KT. EXPECT THE SNOWFALL TO
BECOME MORE SCATTERED IN NATURE TOWARD THE LATER MORNING HOURS.
THE ADVISORY IS CONSEQUENTLY SLATED TO EXPIRE BY 18Z TODAY.
THE REMAINDER OF THE SHORT TERM FORECAST FOR OUR CWA FALLS UNDER A
STEADY AND TIGHTLY PACKED NORTHWEST FLOW ALOFT AS A STRONG UPPER
LEVEL JET ARCS OVER THE ROCKY MOUNTAINS AND CLIPS THE CORNER OF
NORTHEAST MONTANA.
SATURDAY THROUGH SUNDAY...INCREASING INFLUENCE FROM THE
APPROACHING AND BUILDING WESTERN RIDGE PUSHES INTO THE CWA FROM
THE WEST AND SOUTHWEST. LARGE SCALE FORCING FOR ASCENT SHOWS THAT
THERE MAY BE A VERY SMALL AND SUBTLE EMBEDDED DISTURBANCE PACKED
WITHIN THE NORTHWEST FLOW ALOFT WHICH MAY RESULT IN A FEW
SCATTERED SNOW SHOWERS ON SATURDAY...BUT DO NOT EXPECT IT TO BE OF
ANY GREAT SIGNIFICANCE AT THIS TIME. BMICKELSON
.LONG TERM...SUNDAY NIGHT THROUGH FRIDAY...
THE EXTENDED FORECAST BEGINS WITH UPPER RIDGING IN PLACE OVER THE
REGION. THE ATMOSPHERE WARMS QUITE NICELY ACROSS CENTRAL AND
EASTERN MONTANA. LONG RANGE MODELS AGREE ON THIS AND HAVE SHOWN
THIS TREND FOR THE PAST FEW DAYS FOR ABOVE NORMAL CONFIDENCE FOR
SUNDAY NIGHT THROUGH WEDNESDAY MORNING. THEN THE EC AND GFS HEAD
OFF IN DIFFERENT DIRECTIONS...THEREFORE AFTER WEDNESDAY MORNING
THE FORECAST CONFIDENCE FACTOR DROPS OFF SIGNIFICANTLY. GOING TO
SIDE MORE WITH THE GFS FAMILY OVER THE EC. BOTH THE GFS AND EC
MODELS DO SHOW SOME ODDITIES FOR THIS TIME OF YEAR. THE OVERALL
AMOUNT OF CUT OFF LOWS IN EACH MODEL AROUND THE NORTHERN
HEMISPHERE LEADS TO A VERY COMPLICATED PATTERN FOR LARGE SCALE
MODELS TO GIVE A GOOD SOLUTION THAT FAR OUT. THE ENSEMBLES DO NOT
FAVOR EITHER MODEL OR GIVE AN IDEA OF WHICH DIRECTION TO TAKE THE
FORECAST THEREFORE OPTED FOR PERSISTENCE FROM WEDNESDAY AND BEYOND.
MONDAY WILL HIGHLIGHT ABOVE NORMAL TEMPERATURES AND SPRING LIKE
WEATHER FOR THE REGION. TUESDAY A COLD FRONT WILL PUSH THROUGH
NORTHEAST MONTANA... THE FRONTAL TIMING HAS SPED UP THEREFORE DID
TAKE TEMPERATURES DOWN A FEW DEGREES FOR THE EARLIER FRONTAL
PASSAGE. WEDNESDAY AND BEYOND... SLOW WARMING TREND TO KEEP WITH
THE PERSISTENCE TREND. PROTON
&&
.AVIATION...
FLIGHT CONDITIONS WILL BE IMPROVING THROUGH THE MORNING AS THE
AREA OF SNOW MOVES TO THE SOUTHEAST. MVFR CONDITIONS WILL LINGER
THE LONGEST IN THE YELLOWSTONE VALLEY. RAE
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 11 AM MST THIS MORNING FOR CENTRAL
AND SOUTHERN VALLEY...WESTERN ROOSEVELT...MCCONE...RICHLAND...
DAWSON...WIBAUX...EASTERN ROOSEVELT.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
501 PM CST FRI MAR 2 2012
.DISCUSSION...WINDS HAVE INCREASED ACROSS MUCH OF EASTERN NORTH
DAKOTA SUSTAINED AROUND 30 MPH. CALLS TO LAW ENFORCEMENT AND WEB
CAMS INDICATE THAT VISIBILITIES IN OPEN COUNTRY ARE 1/2SM OR LESS
AT TIMES ACROSS MUCH OF THE NORTHERN RED RIVER VALLEY DUE TO
MAINLY BLOWING SNOW. THUS...WILL EXPAND THE WINTER WX ADVISORY
INTO THIS AREA FOR BLOWING SNOW. VISIBILITES REMAIN DECENT ACROSS
THE SOUTHWEST FA...BUT WOULD NOT BE SURPRISED IF BLOWING SNOW
BEGINS TO CAUSE PROBLEMS AS THE TEMPERATURE DROPS (AS IT DID
ACROSS THE NORTH WHEN THE SNOW STARTED BLOWING AROUND). WILL
MONITOR THIS AREA...JUST NOT SURE IF WINDS WILL BE STRONG ENOUGH
BY THE TIME THE TEMPS ACTUALLY DROP.
THE WET ROADS FROM THE AFTERNOON ARE BECOMING ICY AS WELL.
UPDATED FORECAST TO EXPAND AREAS OF BLOWING SNOW INTO THE NEW
ADVISORY AREA...AND PATCHY BLOWING SNOW ACROSS THE SOUTHWEST FA.
INCREASED WIND SPEEDS A BIT. CONTINUED COLD AIR ADVECTION...925MB
WINDS 30-35 KNTOS...AND INCREASED SFC PRESSURE GRADIENT SHOULD
KEEP ELEVATED WINDS THROUGH MIDNIGHT (EVEN WITH LOSS OF SOLAR).
&&
.AVIATION...SLOW PROGRESSION OF SFC LOW AND PRESENCE OF WRAP
AROUND MOISTURE WILL KEEP CIGS/VSBY DOWN INTO MVFR/IFR TERRITORY
THRU THE TAF PERIOD. OTHERWISE...BEHIND THE SYSTEM...BREEZY NORTH
WINDS WILL RESULT IN BLSN WEST OF THE RED RIVER...AND PROGRESSING
EAST THROUGH THE PERIOD.
&&
.PREV DISCUSSION... /ISSUED 218 PM CST FRI MAR 2 2012/
SHORT TERM...
WINDS INCREASING OVER THE RED RIVER VALLEY THIS AFTERNOON INTO THE
EVENING AND WILL MAINTAIN WINTER WX ADVISORY OVER THE FAR NORTH AS
VSBYS REMAIN POOR. AREAS FROM LANGDON TO CAVALIER AND WALHALLA
RECEIVED AROUND 5 OR 6 INCHES OF FRESH SNOW FROM LAST EVENING INTO
THIS MORNING AND THESE WINDS WILL CONTINUE CAUSE REDUCED
VISIBILITY DUE TO BLOWING SNOW.
CANADIAN AND US RADAR COMPOSITE SHOWS THE MAIN SNOW BANDS NOW
WEAKENING OVER THE AREA WITH JUST LIGHT SNOW CONTINUING TO MOVE
SOUTH AND WRAP AROUND THE 500 MB LOW WHICH IS OVER GRAND FORKS AT
19Z. EXPECT TO SEE CONTINUED LIGHT SNOW INTO THE EVENING WITH A
GRADUAL SPREAD EAST IN TIME AND ENDING FROM THE WEST AS THE NIGHT
PROGRESSES. AN INCH OR SO IN NORTHWEST MN TONIGHT SEEMS REASONABLE
WITH LESS THAN THAT IN OTHER AREAS. FOR THE HEAVIER SNOWPACK AREAS
OF THE SOUTHERN VALLEY BLOWING SNOW SHOULD NOT BE A HUGE ISSUE AS
THE SNOW PACK IS QUITE HEAVY FROM PREV WET SNOW AND SNOWFALL THIS
AFTN-EVE NOT ENOUGH TO CAUSE ISSUES. BUT EVE SHIFT CAN MONITOR.
WINDS WILL BE GUSTY TO 35 MPH AT TIMES...WITH RUC AND OTHER SHORT
TERM MODELS SHOWING MIXING UP TO NR 925 MB WHERE WINDS WILL BE
30-35 KTS THRU 06Z. BORDERLINE WIND ADVISORY....BUT SUSTAINED
LIKELY JUST BLO THRESHOLDS.
WEAK RIDGE OF HIGH PRESSURE WILL BUILD EAST INTO ERN ND SATURDAY
WITH SOME CLEARING EXPECTED OVER ERN ND INTO THE VALLEY. DEPARTING
SYSTEM WILL GENERATE LEFTOVER LIGHT SNOW/FLURRIES IN FAR EASTERN
FCST AREA UNTIL NOON. HIGH PRESSURE WILL MOVE INTO MN SAT NIGHT.
DID REMOVE THE WIDESPREAD LOW POPS WE HAD IN THE FCST FOR ERN ND
INTO THE RED RIVER VALLEY SATURDAY AND REMOVED POPS FOR NW MN SAT
AFTN-NIGHT. WITH HIGH OVERHEAD AND POTENTIAL FOR CLEARING LOOKS
CHILLY AT NIGHT WITH OVERNIGHT LOWS SAT NIGHT IN THE SINGLE DIGITS
IN MANY AREAS.
NEXT THREAT FOR SOME LIGHT SNOW WILL BE OVERNIGHT SATURDAY NIGHT
AND INTO SUNDAY MAINLY OVER ERN ND INTO THE SRN VALLEY AS A WEAK
SHORT WAVE DROPS THRU CNTRL ND INTO ERN SD/SW MN. PRECIP WITH THIS
SYSTEM QUITE WEAK.
HIGH PRESSURE TO BUILD IN SUN NIGHT THEN WINDS WILL TURN SOUTH-
SOUTHWEST ON MONDAY AS A STORM SYSTEM GATHERS STRENGTH OVER
ALBERTA. THIS SHOULD BRING MILDER AIR INTO THE REGION.
LONG TERM (MON NIGHT-FRI)...
MODELS INITIALIZED WELL THIS RUN...BUT SOME DIFFERENCES SHOWING UP
IN PLACEMENT OF THE SFC FRONT FOR TUESDAY. OVERALL TRENDS STILL LOOK
GOOD FOR SHIFT TO A PROGRESSIVE PATTERN THROUGH THE END OF THE
PERIOD. THUS...CONTINUED TO LOOK AT A BLEND FOR THE GENERAL TIMING
OF THE FEATURES. THE 500HPA RIDGE IS EXPECTED TO SHIFT EAST WITH
THICKNESS VALUES INCREASING...SO EXPECTING TEMPS TO BE NEAR OR
SLIGHTLY ABOVE SEASONAL NORMS. BY THE END OF THE PERIOD...LOOK FOR
ANOTHER COLD FRONTAL PASSAGE...WITH ANOTHER CHANCE FOR MEASURABLE
PCPN.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR
NDZ006>008-014>016-024-026>030-054.
MN...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR MNZ001-
004-007.
&&
$$
TG
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
218 PM CST FRI MAR 2 2012
.SHORT TERM...
WINDS INCREASING OVER THE RED RIVER VALLEY THIS AFTERNOON INTO THE
EVENING AND WILL MAINTAIN WINTER WX ADVISORY OVER THE FAR NORTH AS
VSBYS REMAIN POOR. AREAS FROM LANGDON TO CAVALIER AND WALHALLA
RECEIVED AROUND 5 OR 6 INCHES OF FRESH SNOW FROM LAST EVENING INTO
THIS MORNING AND THESE WINDS WILL CONTINUE CAUSE REDUCED
VISIBILITY DUE TO BLOWING SNOW.
CANADIAN AND US RADAR COMPOSITE SHOWS THE MAIN SNOW BANDS NOW
WEAKENING OVER THE AREA WITH JUST LIGHT SNOW CONTINUING TO MOVE
SOUTH AND WRAP AROUND THE 500 MB LOW WHICH IS OVER GRAND FORKS AT
19Z. EXPECT TO SEE CONTINUED LIGHT SNOW INTO THE EVENING WITH A
GRADUAL SPREAD EAST IN TIME AND ENDING FROM THE WEST AS THE NIGHT
PROGRESSES. AN INCH OR SO IN NORTHWEST MN TONIGHT SEEMS REASONABLE
WITH LESS THAN THAT IN OTHER AREAS. FOR THE HEAVIER SNOWPACK AREAS
OF THE SOUTHERN VALLEY BLOWING SNOW SHOULD NOT BE A HUGE ISSUE AS
THE SNOW PACK IS QUITE HEAVY FROM PREV WET SNOW AND SNOWFALL THIS
AFTN-EVE NOT ENOUGH TO CAUSE ISSUES. BUT EVE SHIFT CAN MONITOR.
WINDS WILL BE GUSTY TO 35 MPH AT TIMES...WITH RUC AND OTHER SHORT
TERM MODELS SHOWING MIXING UP TO NR 925 MB WHERE WINDS WILL BE
30-35 KTS THRU 06Z. BORDERLINE WIND ADVISORY....BUT SUSTAINED
LIKELY JUST BLO THRESHOLDS.
WEAK RIDGE OF HIGH PRESSURE WILL BUILD EAST INTO ERN ND SATURDAY
WITH SOME CLEARING EXPECTED OVER ERN ND INTO THE VALLEY. DEPARTING
SYSTEM WILL GENERATE LEFTOVER LIGHT SNOW/FLURRIES IN FAR EASTERN
FCST AREA UNTIL NOON. HIGH PRESSURE WILL MOVE INTO MN SAT NIGHT.
DID REMOVE THE WIDESPREAD LOW POPS WE HAD IN THE FCST FOR ERN ND
INTO THE RED RIVER VALLEY SATURDAY AND REMOVED POPS FOR NW MN SAT
AFTN-NIGHT. WITH HIGH OVERHEAD AND POTENTIAL FOR CLEARING LOOKS
CHILLY AT NIGHT WITH OVERNIGHT LOWS SAT NIGHT IN THE SINGLE DIGITS
IN MANY AREAS.
NEXT THREAT FOR SOME LIGHT SNOW WILL BE OVERNIGHT SATURDAY NIGHT
AND INTO SUNDAY MAINLY OVER ERN ND INTO THE SRN VALLEY AS A WEAK
SHORT WAVE DROPS THRU CNTRL ND INTO ERN SD/SW MN. PRECIP WITH THIS
SYSTEM QUITE WEAK.
HIGH PRESSURE TO BUILD IN SUN NIGHT THEN WINDS WILL TURN SOUTH-
SOUTHWEST ON MONDAY AS A STORM SYSTEM GATHERS STRENGTH OVER
ALBERTA. THIS SHOULD BRING MILDER AIR INTO THE REGION.
.LONG TERM (MON NIGHT-FRI)...
MODELS INITIALIZED WELL THIS RUN...BUT SOME DIFFERENCES SHOWING UP
IN PLACEMENT OF THE SFC FRONT FOR TUESDAY. OVERALL TRENDS STILL LOOK
GOOD FOR SHIFT TO A PROGRESSIVE PATTERN THROUGH THE END OF THE
PERIOD. THUS...CONTINUED TO LOOK AT A BLEND FOR THE GENERAL TIMING
OF THE FEATURES. THE 500HPA RIDGE IS EXPECTED TO SHIFT EAST WITH
THICKNESS VALUES INCREASING...SO EXPECTING TEMPS TO BE NEAR OR
SLIGHTLY ABOVE SEASONAL NORMS. BY THE END OF THE PERIOD...LOOK FOR
ANOTHER COLD FRONTAL PASSAGE...WITH ANOTHER CHANCE FOR MEASURABLE
PCPN.
&&
.AVIATION...
SLOW PROGRESSION OF SFC LOW AND PRESENCE OF WRAP AROUND MOISTURE
WILL KEEP CIGS/VSBY DOWN INTO MVFR/IFR TERRITORY THRU THE TAF
PERIOD. OTHERWISE...BEHIND THE SYSTEM...BREEZY NORTH WINDS WILL
RESULT IN BLSN WEST OF THE RED RIVER...AND PROGRESSING EAST THROUGH
THE PERIOD.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR
NDZ006>008-014-015.
MN...NONE.
&&
$$
RIDDLE/HOPKINS
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
240 PM EST FRI MAR 2 2012
.SYNOPSIS...
SHOWERS AND THUNDERSTORMS WITH COLD FRONT LATE FRIDAY...SOME STORMS
COULD BE STRONG TO SEVERE. COOLER WEATHER ESTABLISHES FOR THE
WEEKEND INTO EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
SHOWERS AND THUNDERSTORMS ASSOCIATED WITH AN APPROACHING WARM FRONT
AND MOISTURE PUNCH HAVE BEEN ONGOING ACROSS THE FORECAST AREA SINCE
MID MORNING. WRFNMM...HRRR...AND CURRENT RADAR HAVE SOME SMALL
TIMING DIFFERENCES...HOWEVER ALL AGREE THAT THERE WILL BE A BREAK IN
THE SHOWERS AND STORMS FOLLOWING THE WARM FRONT...PRIOR TO THE COLD
FRONT ARRIVING LATER THIS EVENING. RECENT RUC BUFKIT SOUNDINGS SHOW
JUST OVER 500J/KG CAPE IN EASTERN KY/WESTERN WV AHEAD OF THE COLD
FRONT LATER THIS EVENING...SO STILL THINKING STRONG TO SEVERE
THUNDERSTORMS POSSIBLE AHEAD OF THE FRONT. WITH THE TIME OF DAY THE
STORMS ARE EXPECTED...WE MAY SEE DECREASING THERMODYNAMICS AS THE
STORMS MOVE INTO CENTRAL WV. HOWEVER WITH PLENTY OF SHEAR AND
DYNAMIC LIFT FROM THE FRONT...STORMS SHOULD STILL BE ABLE TO SUPPORT
DAMAGING WINDS AND HAIL...AND POSSIBLY AN ISOLATED TORNADO.
COLD FRONT PASSAGE EXPECTED FROM FROM NW TO SE AROUND 03-06Z
TONIGHT. PRECIP CHANCES DECREASE QUICKLY AFTER THE FRONT MOVES
THROUGH.
NOT A REAL STRONG COLD PUNCH IMMEDIATELY AFTER THE FRONT...AND WITH
SOME GUSTY WINDS HANGING AROUND...WILL REMAINED WELL MIXED SO TEMPS
SHOULD REMAIN FAIRLY STEADY MOST OF THE NIGHT WITH A GRADUALLY
DECREASE THROUGH THE EARLY MORNING HOURS. TRENDED TOWARDS THE MET
AND THEN MADE SOME MINOR TWEAKS TO HOLD THE TEMPS STEADIER AT FIRST.
&&
.SHORT TERM /SATURDAY THROUGH MONDAY/...
CAA REGIME SETTING UP FOR THE WEEKEND. SAT SHOULD SEE SUN EARLY
BEFORE STRONGER CAA LATE IN THE DAY ALLOWS FOR STRATOCU AND CU TO
DEVELOP AS UPR TROF PIVOTS IN. DESPITE H85 TEMPS -2 TO -6....THINK
ENOUGH MIXING WILL OCCUR FOR THE WARMER NUMBERS OFF GUIDANCE TO
BECOME REALIZED. FLOW COMES MORE CONDUCIVE FOR UPSLOPE SUN INTO SUN
NIGHT AS UPR TROF AXIS SWINGS THRU. INHERITED SNOW/POP GRIDS
GENERALLY LOOKED GOOD AND ONLY NEEDED SOME FINESSING. ALLOWED FOR A
HIGH THRESHOLD FOR RAIN/SNOW DURING DAY SUN BASED ON TEMPS ALOFT.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
PRIMARY FORECAST CONCERN WILL BE A CHANCE OF PRECIPITATION SUNDAY
NIGHT INTO MONDAY AS A SHORTWAVE TROUGH MOVES BY THE REGION.
SUNDAY NIGHT...INITIALLY LARGE SCALE FORCING FOR ASCENT PUSHES
EASTWARD OUT OF THE AREA BUT WILL QUICKLY REDEVELOP DURING THE
OVERNIGHT HOURS AS A SHORTWAVE MOVES NW-SE THROUGH THE MEAN FLOW
AROUND THE UPPER LEVEL TROUGH BASE. THIS FORCING IS MAXIMIZED OVER
THE SOUTHERN CWA AROUND 12Z MON BEFORE LARGE SCALE SUBSIDENCE
QUICKLY DEVELOPS ACROSS AREA BY 18Z MON IN ITS WAKE...WITH TROUGH
AXIS EAST OF AREA BY THEN. IN ADDITION...GOOD PVA AND LOW LEVEL WARM
ADVECTION AT BOTH 700MB AND 850MB SHOULD BE ENOUGH TO GENERATE SOME
PRECIP OVER THE AREA...WITH HIGHEST POPS ACROSS SOUTHERN AND WESTERN
CWA BTWN 06Z-12Z MON. TEMPS WILL DROP INTO THE LOWER 30S MOST
LOCATIONS BY 06Z AND WITH MODEL CONSENSUS QPF AROUND THE 0.1 TO 0.2
INCH RANGE...AN INCH OR TWO OF SNOW WILL BE POSSIBLE.
PRECIP WILL BY AND LARGE COME TO END BY MIDDAY MONDAY BUT WILL
CONTINUE SLIGHT CHANCE/LOW CHANCE POPS MAINLY ACROSS SOUTHERN ZONES
AND MOUNTAINS UNTIL 00Z TUE TO ACCOUNT FOR PLENTIFUL LOW LEVEL
MOISTURE IN PLACE WITH A 700MB BAROCLINIC ZONE PROGGED NEAR THE
WESTERN/SOUTHERN CWA MON AFTERNOON. SNOW WILL CHANGE TO RAIN HOWEVER
ACROSS LOWLANDS AS TEMPS WARM THROUGH THE 30S INTO THE 40S. ALL
PRECIP SHOULD END BY TUE 00Z WITH CLEARING SKIES. TUE MORNING WILL
BE COLDEST MORNING DURING THE PERIOD. WITH 925MB TEMPS AROUND -3C TO
-4C 12Z TUE AND MOSTLY CLEAR SKIES/LIGHT WINDS...HAVE CONTINUED TO
LOWER MINS A FEW DEGREES DOWN INTO THE LOW 20S ACROSS THE LOWLANDS.
HIGHS TUE WILL WARM TO NEAR SEASONAL LEVELS AND INTO THE 60S WED/THU
AS UPPER LEVEL RIDGING BUILDS INTO THE REGION.
&&
.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
SHOWERS AND THUNDERSTORMS ONGOING ACROSS FORECAST AREA. THESE ARE
STILL AHEAD OF THE WARM FRONT...SO EXPECT AT LEAST SCATTERED
ACTIVITY TO CONTINUE AS THE WARM FRONT MOVES THROUGH AND THE WARM
SECTOR TAKES OVER. TRIED TO TIME OUT A BRIEF BREAK...OR AT LEAST A
REDUCTION IN PRECIP COVERAGE BETWEEN THE WARM FRONT ACTIVITY THIS
AFTERNOON AND THEN THE COLD FRONT BASED PRECIP FOR LATER THIS
EVENING. WITH THAT SAID...STILL KEPT MAINLY MVFR CONDITIONS
THROUGHOUT WITH SCATTERED SHOWERS AND THUNDERSTORMS. WILL HANDLE
LOWER CIGS AND VSBYS IN HEAVIER SHOWERS WITH TEMPOS AS NEEDED.
AFOREMENTIONED COLD FRONT WILL COME THROUGH LATE THIS EVENING...INTO
THE OVERNIGHT...BRINGING INCREASED THUNDERSTORM ACTIVITY...WITH
STRONG TO SEVERE STORMS POSSIBLE AHEAD OF THE FRONT. STRONG GUSTY
WINDS AND HAIL SHOULD BE THE MAIN THREAT. SHOWERS AND THUNDERSTORMS
SHOULD DIMINISH PRETTY RAPIDLY AFTER THE COLD FRONT MOVES THROUGH.
AS THE WARM FRONT PASSES TODAY...SYNOPTIC FLOW WILL BECOME GUSTY OUT
OF THE SOUTH. THEN AS THE COLD FRONT PASSES ACROSS THE AREA...FROM
03Z TO 07Z...WINDS WILL BEGIN TO TURN TO THE WEST BUT REMAIN ON THE
GUSTY SIDE.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z SATURDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: UNCERTAINTY REMAINS ON EXACT TIMING AND
LOCATIONS OF STRONGEST CONVECTION AND RELATED MVFR AND IFR
CONDITIONS. TEMPOS MAY BE NEEDED FOR BRIEF IFR...GUSTY THUNDERSTORM
WINDS...AND HEAVY RAIN/THUNDERSTORMS.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 20 21 22 23 00 01 02 03 04 05 06 07
EST 1HRLY 15 16 17 18 19 20 21 22 23 00 01 02
CRW CONSISTENCY M M H H M M M M M M M M
HTS CONSISTENCY M M M M M M M L M M H H
BKW CONSISTENCY L L L L L M M M M M M M
EKN CONSISTENCY M M H H M L M M M M M M
PKB CONSISTENCY L L L L H L M M M M H M
CKB CONSISTENCY H M M M M H H M M M M M
AFTER 18Z SATURDAY...
MVFR TO IFR POSSIBLE IN MOUNTAIN SNOW SHOWERS SATURDAY AFTERNOON THROUGH
SUNDAY.
&&
.HYDROLOGY...
GIVEN LOW FFG VALUES AND SEVERAL ROUNDS OF SHOWERS AND HEAVY
THUNDERSTORMS...SOME AREA WILL EASILY RECEIVE EXCESSIVE RUNOFF
RESULTING IN FLOODING. THE MOST VULNERABLE AREA INCLUDE N CNTRL WV
AND A SMALL AREA IN NORTHERN ATHENS AND SOUTHERN WASHINGTON
COUNTY...WHERE AS LITTLE AS THREE QUARTERS OF AN INCH WITHIN AN HOUR
COULD START CAUSING PROBLEMS.
FFA ISSUED FOR ALL BUT EXTREME WESTERN COUNTIES BEGINNING 2 PM THIS
AFTERNOON AND RUNNING THROUGH THE OVERNIGHT. THE WESTERN COUNTIES
ARE DRIER AND WILL NOT RECEIVE QUITE AS MUCH RAINFALL. OTHERWISE PW
VALUES OF 1-1.2 INCHES AND 60 KTS OF LOW LEVEL FEED WILL EASILY
SUPPORT RAINFALL AMOUNTS OVER AN INCH...WITH AREA THAT GET HIT HARD
MORE THAN ONCE PUSHING TWO INCHES.
NO MAJOR MAINSTEM RIVER PROBLEMS ARE EXPECTED AT THIS TIME ALTHOUGH
MOST GAGES SHOULD GET AT LEAST AS HIGH AS THEY DID FROM THE LAST
EVENT.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR WVZ005>011-013>020-
024>040-046-047.
OH...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR OHZ067-075-076-
085>087.
KY...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR KYZ101>103-105.
VA...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR VAZ003-004.
&&
$$
SYNOPSIS...MZ/GG/30
NEAR TERM...MZ
SHORT TERM...30
LONG TERM...GG
AVIATION...MZ
HYDROLOGY...TRM
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1138 AM CST FRI MAR 2 2012
.SHORT TERM...TODAY AND TONIGHT
1032 AM CST FRI MAR 2 2012
THE MAIN CONCERN COMING IN THIS MORNING WAS WITH WHETHER THE MAIN
BAND COULD SET UP ACROSS THE SOUTHERN PORTION OF GRANT COUNTY
WHERE WE WOULD END UP WITH ADVISORY WORTHY SNOW THERE. THE LATEST
RADAR RETURNS ALONG WITH REGIONAL OBSERVATIONS SHOW THAT THIS BAND
OF HEAVY SNOW HAS SET UP NEAR PLATTEVILLE DOWN TOWARD CEDAR RAPIDS
AND LIKELY WILL NOT SHIFT MUCH TO THE WEST THROUGH THE REST OF
TODAY AS THE DEEPENING NEGATIVELY TILTED MID LEVEL LOW LIFTS UP
INTO THE WESTERN GREAT LAKES REGION. THE 02.13Z HRRR AND PREVIOUS
RUNS HAVE BEEN FAIRLY CONSISTENT THIS MORNING WITH BRINGING THIS
SNOW BAND ACROSS SOUTHWEST WISCONSIN THIS AFTERNOON BEFORE
WEAKENING THE BAND AND TAKING IT EAST TONIGHT. WITH ABOUT A 6 HOUR
WINDOW FOR HEAVY SNOW...THINKING IS THAT THE POTENTIAL IS THERE
FOR AT LEAST 3 INCHES TO AS MUCH AS 6 INCHES WITH AN INCH PER HOUR
FALLING AT TIMES UNDER THE BAND. THEREFORE...HAVE ISSUED A WINTER
WEATHER ADVISORY FOR GRANT COUNTY WHERE THE THREAT IS THE
GREATEST. CONSIDERED ADDING RICHLAND AND ADAMS COUNTY AS
WELL...BUT THINK THAT THE BAND SHOULD STAY JUST TO THEIR EAST OR
AT WORST CATCH A SLIVER OF THE COUNTY. WILL CONTINUE TO MONITOR
CONDITIONS THROUGH THIS AFTERNOON PARTICULARLY ACROSS THESE
COUNTIES. WENT WITH AN END TIME OF 9PM TO MATCH UP WITH
NEIGHBORING END TIMES...BUT THINK THAT WE MAY BE ABLE TO END IT A
LITTLE EARLIER THAN THAT THIS EVENING.
OTHERWISE...ALSO HAD TO ADJUST THE SNOW DEVELOPING ACROSS A
SECONDARY BAND TO THE WEST OF THIS ONE FROM STEVENS POINT
SOUTHWEST TO LA CROSSE AND OELWEIN. SNOWFALL AMOUNTS ARE STILL
EXPECTED TO REMAIN AT LESS THAN AN INCH ACROSS THIS BAND.
.LONG TERM...SUNDAY NIGHT THROUGH THURSDAY
310 AM CST FRI MAR 2 2012
UPPER LEVEL RIDGING WILL BE OVER THE UPPER MIDWEST UNTIL LATE IN
THE PERIOD. BOTH THE ECMWF AND 02.00Z GFS SHOW A LONG WAVE TROUGH
CROSSING THE CENTRAL PART OF THE COUNTRY BUT SHOW CONSIDERABLE
DIFFERENCES ON ITS STRENGTH. A COLD FRONT SHOULD CROSS THE REGION
WEDNESDAY AND WEDNESDAY NIGHT WITH A CHANCE OF SOME PRECIPITATION
BEFORE PUSHING EAST OF THE AREA THURSDAY. TEMPERATURES AHEAD OF
THIS FRONT ARE EXPECTED TO WARM TO ABOUT 10C AT 850 MB. THE GFS
BUFKIT SOUNDING SUGGESTS THE POTENTIAL TO MIX UP TO ABOUT THIS
LEVEL WHICH COULD PUSH SURFACE TEMPERATURES WELL INTO THE 50S FOR
MUCH OF THE AREA.
&&
.AVIATION...THROUGH 18Z SATURDAY
1138 AM CST FRI MAR 2 2012
DESPITE A NEARBY WINTER STORM...CONDITIONS SHOULD REMAIN RATHER
FAVORABLE AT BOTH TAF SITES WITH JUST SOME MVFR CEILINGS TO
CONTEND WITH AT LSE THIS AFTERNOON. IFR CEILINGS HAVE LIFTED AT
RST AND SHOULD STAY VFR THROUGH THE AFTERNOON AS WELL. AS THE
SYSTEM PULLS OUT TO THE EAST THROUGH THE GREAT LAKES
TONIGHT...WINDS WILL BE ON THE INCREASE OUT OF THE WEST AS COLDER
AIR DROPS INTO THE REGION. SOME SNOW WILL BE POSSIBLE AS WELL
OVERNIGHT INTO SATURDAY WHICH WILL AT LEAST BRING CEILINGS BACK
DOWN TO MVFR WITH SOME IFR VISIBILITIES POSSIBLE DUE TO THE SNOW.
WIND GUSTS OF 20 TO 30KTS ARE EXPECTED OVERNIGHT INTO TOMORROW AT
BOTH TAF SITES.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
1032 AM CST FRI MAR 2 2012
WI...WINTER WEATHER ADVISORY UNTIL 9 PM CST THIS EVENING FOR WIZ061.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM...04
AVIATION...HALBACH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1032 AM CST FRI MAR 2 2012
.SHORT TERM...TODAY AND TONIGHT
1032 AM CST FRI MAR 2 2012
THE MAIN CONCERN COMING IN THIS MORNING WAS WITH WHETHER THE MAIN
BAND COULD SET UP ACROSS THE SOUTHERN PORTION OF GRANT COUNTY
WHERE WE WOULD END UP WITH ADVISORY WORTHY SNOW THERE. THE LATEST
RADAR RETURNS ALONG WITH REGIONAL OBSERVATIONS SHOW THAT THIS BAND
OF HEAVY SNOW HAS SET UP NEAR PLATTEVILLE DOWN TOWARD CEDAR RAPIDS
AND LIKELY WILL NOT SHIFT MUCH TO THE WEST THROUGH THE REST OF
TODAY AS THE DEEPENING NEGATIVELY TILTED MID LEVEL LOW LIFTS UP
INTO THE WESTERN GREAT LAKES REGION. THE 02.13Z HRRR AND PREVIOUS
RUNS HAVE BEEN FAIRLY CONSISTENT THIS MORNING WITH BRINGING THIS
SNOW BAND ACROSS SOUTHWEST WISCONSIN THIS AFTERNOON BEFORE
WEAKENING THE BAND AND TAKING IT EAST TONIGHT. WITH ABOUT A 6 HOUR
WINDOW FOR HEAVY SNOW...THINKING IS THAT THE POTENTIAL IS THERE
FOR AT LEAST 3 INCHES TO AS MUCH AS 6 INCHES WITH AN INCH PER HOUR
FALLING AT TIMES UNDER THE BAND. THEREFORE...HAVE ISSUED A WINTER
WEATHER ADVISORY FOR GRANT COUNTY WHERE THE THREAT IS THE
GREATEST. CONSIDERED ADDING RICHLAND AND ADAMS COUNTY AS
WELL...BUT THINK THAT THE BAND SHOULD STAY JUST TO THEIR EAST OR
AT WORST CATCH A SLIVER OF THE COUNTY. WILL CONTINUE TO MONITOR
CONDITIONS THROUGH THIS AFTERNOON PARTICULARLY ACROSS THESE
COUNTIES. WENT WITH AN END TIME OF 9PM TO MATCH UP WITH
NEIGHBORING END TIMES...BUT THINK THAT WE MAY BE ABLE TO END IT A
LITTLE EARLIER THAN THAT THIS EVENING.
OTHERWISE...ALSO HAD TO ADJUST THE SNOW DEVELOPING ACROSS A
SECONDARY BAND TO THE WEST OF THIS ONE FROM STEVENS POINT
SOUTHWEST TO LA CROSSE AND OELWEIN. SNOWFALL AMOUNTS ARE STILL
EXPECTED TO REMAIN AT LESS THAN AN INCH ACROSS THIS BAND.
.LONG TERM...SUNDAY NIGHT THROUGH THURSDAY
310 AM CST FRI MAR 2 2012
UPPER LEVEL RIDGING WILL BE OVER THE UPPER MIDWEST UNTIL LATE IN
THE PERIOD. BOTH THE ECMWF AND 02.00Z GFS SHOW A LONG WAVE TROUGH
CROSSING THE CENTRAL PART OF THE COUNTRY BUT SHOW CONSIDERABLE
DIFFERENCES ON ITS STRENGTH. A COLD FRONT SHOULD CROSS THE REGION
WEDNESDAY AND WEDNESDAY NIGHT WITH A CHANCE OF SOME PRECIPITATION
BEFORE PUSHING EAST OF THE AREA THURSDAY. TEMPERATURES AHEAD OF
THIS FRONT ARE EXPECTED TO WARM TO ABOUT 10C AT 850 MB. THE GFS
BUFKIT SOUNDING SUGGESTS THE POTENTIAL TO MIX UP TO ABOUT THIS
LEVEL WHICH COULD PUSH SURFACE TEMPERATURES WELL INTO THE 50S FOR
MUCH OF THE AREA.
&&
.AVIATION...TODAY AND TONIGHT
543 AM CST FRI MAR 2 2012
CURRENTLY...WIDESPREAD MVFR STRATOCUMULUS IN PLACE ACROSS EASTERN
MN INTO WI IN THE WAKE OF AN UPPER LEVEL DISTURBANCE ROTATING
THROUGH NORTHEAST MN/UPPER MICHIGAN. OTHERWISE...WILL BE WATCHING
A STRONG AREA OF LOW PRESSURE MOVE NORTHEAST FROM MISSOURI INTO
LOWER MICHIGAN TODAY. MAIN IMPACT ON THE KRST/KLSE TAF SITES WILL
BE CLOUDS...WITH ANY ACCUMULATING SNOW EXPECTED TO REMAIN
SOUTHEAST OF A LINE FROM NECEDAH AND PRAIRIE DU CHIEN WI THROUGH
OELWEIN IA. KLSE MAY BE CLOSE ENOUGH FOR SOME FLURRIES. MVFR CLOUD
COVER EXPECTED TO SCATTER INTO MID-CLOUD/VFR CONDITIONS AT KRST
AROUND 18Z AND AT KLSE BY 03.00Z. A MID-LEVEL TROUGH WILL THEN
PIVOT SOUTHEAST INTO THE AREA TONIGHT...BRINGING MVFR CLOUDS AND
SCATTERED -SN/FLURRY ACTIVITY AROUND 06Z AND AT KLSE AROUND 08Z.
WILL ALSO BE WATCHING FOR GUSTY WEST/NORTHWEST WINDS GOING INTO
THIS EVENING/OVERNIGHT AS THE SURFACE PRESSURE GRADIENT INCREASES.
GUSTS ARE EXPECTED TO BE IN THE 20-30KT RANGE AFTER 03Z.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
1032 AM CST FRI MAR 2 2012
WI...WINTER WEATHER ADVISORY UNTIL 9 PM CST THIS EVENING FOR WIZ061.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM...04
AVIATION...DAS