Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 03/08/13
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1103 AM MST WED MAR 6 2013
.UPDATE...AMENDED THE ZONES FOR SLIGHTLY COOLER TEMPERATURES ON
PLAINS TODAY...AND STRONGER SOUTHEAST WINDS FAR NORTHEAST PLAINS.
&&
.AVIATION...SOUTHEAST TO NORTHEAST WINDS TODAY WILL GIVE WAY TO
DRAINAGE WINDS TONIGHT.
&&
.PREV DISCUSSION... /ISSUED 1000 AM MST WED MAR 6 2013/
UPDATE...WILL CLOSELY WATCH MIXING TODAY...MID SHIFT DID
DELINIATE FOR SNOW ON GROUND WITH COOLER MAXES FROM SOUTHERN WELD
TO NORTHEASTERN ELBERT COUNTIES. THERE IS ALSO SOME CLOUDS TO
ACCOUNT FOR IN THESE AREAS. OTHERWISE NO CHANGES EXPECTED.
AVIATION...A BIT OF HAZE AT KDIA WILL DISSIPATE WITH MIXING
TODAY...SO LOOKING FOR DRY VFR CONDITIONS WITH LIGHT WINDS.
PREV DISCUSSION... /ISSUED 408 AM MST WED MAR 6 2013/
SHORT TERM...SWLY FLOW ALOFT WILL DEVELOP OVER THE AREA AS THE
UPPER LEVEL RIDGE SHIFTS EAST. SOME HIGHER LEVEL CLOUDS WILL BE
POSSIBLE OTHERWISE IT WILL REMAIN DRY THRU TONIGHT. ONCE AGAIN
HIGH TEMPS THIS AFTN WILL BE THE MAIN ISSUE. SOME DEEPER SNOW
COVER STILL RESIDES OVER SRN WELD...CNTRL AND ERN PORTIONS OF ADAMS
AND ARAPAHOE ALONG WITH ELBERT COUNTIES WHICH WILL AFFECT AFTN
HIGHS IN THESE AREAS AS READINGS MAY NOT GET OUT OF THE 40S.
MEANWHILE NR THE FOOTHILLS LIGHT WLY DOWNSLOPE FLOW WILL DVLP
WHICH MAY ALLOW FOR HIGHS TO REACH THE LOWER 60S OVER THE WRN AND
SRN SUBURBS OF DENVER. THUS WILL SEE QUITE A TEMP DIFFERENCE ALONG
THE FRONT RANGE THIS AFTN. OVER THE PLAINS WHERE NO SNOW COVER
EXISTS WINDS WILL BE MAINLY SELY SO WILL KEEP AFTN HIGHS IN THE
LOWER TO MID 50S EXCEPT OVER SRN LINCOLN COUNTY WHERE LOWER 60S
WILL BE POSSIBLE DUE TO SWLY LOW LVL WINDS. FOR TONIGHT MAY SEE
SOME PATCHY FOG DVLP OVER THE FAR NERN PLAINS AFTER MIDNIGHT.
LONG TERM...THURSDAY WILL BE DRY AND WARM AS SOUTHWESTERLY FLOW
ALOFT COVERS THE STATE. FRIDAY WILL BE A TRANSITIONAL DAY AS
SOUTHWEST FLOW ALOFT CONTINUES BUT MOISTURE BEGINS INCREASING
AHEAD OF A POTENT UPPER LOW MOVING OVER THE DESERT SOUTHWEST. AND
SATURDAY LOOKS LIKE IT WILL BE THE MOST CRITICAL DAY OF THIS
FORECAST PACKAGE. EACH OF THE SYNOPTIC MODELS SHOW THE STRONG
UPPER LEVEL LOW PRESSURE SYSTEM MOVING ACROSS OR NEAR THE FOUR
CORNERS AREA ON SATURDAY...SETTING UP A SNOW PATTERN FOR NORTHEAST
COLORADO. HOWEVER...AGREEMENT BETWEEN THE MODELS IS FAR FROM
UNANIMOUS. THE GFS IS MORE PROGRESSIVE THAN THE ECMWF AND THE NAM
ONLY GOES OUT TO MIDDAY SATURDAY BUT SHOWS AGREEMENT WITH THE GFS.
PRECIPITATION AMOUNTS ALSO VARY BETWEEN THE DIFFERENT MODELS. THE
NAM SHOWS AN INITIALLY DRY SWATH OF AIR MOVING ACROSS THE EASTERN
PLAINS WITH THE EJECTING UPPER LOW...WHILE THE GFS GENERATES
COPIOUS AMOUNTS OF SNOWFALL. THE ECMWF SHOWS ONLY LIGHT TO
MODERATE SNOW AMOUNTS THROUGH SATURDAY NIGHT. NEEDLESS TO
SAY...MANY QUESTIONS STILL REMAIN ON HOW BIG THIS STORM IS GOING
TO BE. THE STORM SYSTEM...WHICH IS CURRENTLY DEVELOPING OFF THE
COAST OF OREGON IS GOING TO CONTAIN A LOT OF COLD AIR ALOFT AND
WILL ALSO ENCOUNTER A GOOD SHOT OF LOW LEVEL MOISTURE FROM THE
GULF OF MEXICO WHEN IT MOVES ACROSS COLORADO. MODEL SOUNDINGS SHOW
LAPSE RATES SATURDAY AFTERNOON WILL BE NEARLY MOIST ADIABATIC DUE
TO THE COLD TEMPERATURES ALOFT. IF THE SYSTEM TAKES ITS TIME
MOVING ACROSS COLORADO...SIMILAR TO THE ECMWF SOLUTION...THEN IT
WILL BE ABLE TO PRODUCE SNOW AMOUNTS HEAVIER THAN WHAT THE ECMWF
CONTAINS. THE TIMING OF THE GFS AND NAM SOLUTIONS MAY WELL END UP
BEING TOO FAST AS THE SYSTEM ALREADY LOOKS LIKE IT IS READY TO
CUTOFF FROM THE NORTHERN STREAM IN THE NEXT 24 TO 36 HOURS. GIVEN
ALL THE UNCERATINTY...IT IS TOO EARLY TO ISSUE ANY HIGHLIGHTS...
BUT THAT MAY CHANGE LATER TODAY OR TONIGHT. ALONG WITH THE UPPER
DYNAMICS OF THE PASSING UPPER LOW ON SATURDAY...IT LOOKS LIKE A
STRONG SURGE OF NORTHERLY SURFACE WINDS WILL DEVELOP SATURDAY
AFTERNOON ON THE BACK SIDE OF THE STORM. HAVE ADDED AREAS OF
BLOWING SNOW TO THE SATURDAY AFTERNOON AND EVENING FORECAST.
FOR SUNDAY THROUGH TUESDAY...MODELS SHOW COLORADO UNDER NORTHWEST
FLOW WITH WARMER TEMPERATURES AND DRIER CONDITIONS. TEMPERATURE
FORECASTS FOR THESE DAYS IS GOING TO BE VERY DEPENDENT ON HOW MUCH
SNOW FALLS DURING THE SATURDAY THROUGH SUNDAY PERIOD. FOR THE TIME
BEING...WILL KEEP THIS PART OF THE FORECAST VERY GENERAL.
AVIATION...VFR THRU TONIGHT. WK SFC LOW PRES WILL LIKELY REMAIN
WEST OF THE AIRPORT THRU THIS AFTN. OVERALL THE HRRR AND RAP
KEEP WINDS LIGHT SSW THRU LATE MORNING AND THEN GRADUALLY SHIFTTHEN
MORE ELY BY EARLY AFTN. THE ELY WINDS ARE FCST TO STAY IN PLACE AT
LEAST THRU 23Z BEFORE BECOMING MORE SELY BY 01Z. WINDS WILL THEN
GRADUALLY BECOME DRAINAGE BY 03Z AND CONTINUE THAT WAY OVERNIGHT.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...RTG
LONG TERM....99
AVIATION...RTG
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1000 AM MST WED MAR 6 2013
.UPDATE...WILL CLOSELY WATCH MIXING TODAY...MID SHIFT DID
DELINIATE FOR SNOW ON GROUND WITH COOLER MAXES FROM SOUTHERN WELD
TO NORTHEASTERN ELBERT COUNTIES. THERE IS ALSO SOME CLOUDS TO
ACCOUNT FOR IN THESE AREAS. OTHERWISE NO CHANGES EXPECTED.
&&
.AVIATION...A BIT OF HAZE AT KDIA WILL DISSIPATE WITH MIXING
TODAY...SO LOOKING FOR DRY VFR CONDITIONS WITH LIGHT WINDS.
&&
.PREV DISCUSSION... /ISSUED 408 AM MST WED MAR 6 2013/
SHORT TERM...SWLY FLOW ALOFT WILL DEVELOP OVER THE AREA AS THE
UPPER LEVEL RIDGE SHIFTS EAST. SOME HIGHER LEVEL CLOUDS WILL BE
POSSIBLE OTHERWISE IT WILL REMAIN DRY THRU TONIGHT. ONCE AGAIN
HIGH TEMPS THIS AFTN WILL BE THE MAIN ISSUE. SOME DEEPER SNOW
COVER STILL RESIDES OVER SRN WELD...CNTRL AND ERN PORTIONS OF ADAMS
AND ARAPAHOE ALONG WITH ELBERT COUNTIES WHICH WILL AFFECT AFTN
HIGHS IN THESE AREAS AS READINGS MAY NOT GET OUT OF THE 40S.
MEANWHILE NR THE FOOTHILLS LIGHT WLY DOWNSLOPE FLOW WILL DVLP
WHICH MAY ALLOW FOR HIGHS TO REACH THE LOWER 60S OVER THE WRN AND
SRN SUBURBS OF DENVER. THUS WILL SEE QUITE A TEMP DIFFERENCE ALONG
THE FRONT RANGE THIS AFTN. OVER THE PLAINS WHERE NO SNOW COVER
EXISTS WINDS WILL BE MAINLY SELY SO WILL KEEP AFTN HIGHS IN THE
LOWER TO MID 50S EXCEPT OVER SRN LINCOLN COUNTY WHERE LOWER 60S
WILL BE POSSIBLE DUE TO SWLY LOW LVL WINDS. FOR TONIGHT MAY SEE
SOME PATCHY FOG DVLP OVER THE FAR NERN PLAINS AFTER MIDNIGHT.
LONG TERM...THURSDAY WILL BE DRY AND WARM AS SOUTHWESTERLY FLOW
ALOFT COVERS THE STATE. FRIDAY WILL BE A TRANSITIONAL DAY AS
SOUTHWEST FLOW ALOFT CONTINUES BUT MOISTURE BEGINS INCREASING
AHEAD OF A POTENT UPPER LOW MOVING OVER THE DESERT SOUTHWEST. AND
SATURDAY LOOKS LIKE IT WILL BE THE MOST CRITICAL DAY OF THIS
FORECAST PACKAGE. EACH OF THE SYNOPTIC MODELS SHOW THE STRONG
UPPER LEVEL LOW PRESSURE SYSTEM MOVING ACROSS OR NEAR THE FOUR
CORNERS AREA ON SATURDAY...SETTING UP A SNOW PATTERN FOR NORTHEAST
COLORADO. HOWEVER...AGREEMENT BETWEEN THE MODELS IS FAR FROM
UNANIMOUS. THE GFS IS MORE PROGRESSIVE THAN THE ECMWF AND THE NAM
ONLY GOES OUT TO MIDDAY SATURDAY BUT SHOWS AGREEMENT WITH THE GFS.
PRECIPITATION AMOUNTS ALSO VARY BETWEEN THE DIFFERENT MODELS. THE
NAM SHOWS AN INITIALLY DRY SWATH OF AIR MOVING ACROSS THE EASTERN
PLAINS WITH THE EJECTING UPPER LOW...WHILE THE GFS GENERATES
COPIOUS AMOUNTS OF SNOWFALL. THE ECMWF SHOWS ONLY LIGHT TO
MODERATE SNOW AMOUNTS THROUGH SATURDAY NIGHT. NEEDLESS TO
SAY...MANY QUESTIONS STILL REMAIN ON HOW BIG THIS STORM IS GOING
TO BE. THE STORM SYSTEM...WHICH IS CURRENTLY DEVELOPING OFF THE
COAST OF OREGON IS GOING TO CONTAIN A LOT OF COLD AIR ALOFT AND
WILL ALSO ENCOUNTER A GOOD SHOT OF LOW LEVEL MOISTURE FROM THE
GULF OF MEXICO WHEN IT MOVES ACROSS COLORADO. MODEL SOUNDINGS SHOW
LAPSE RATES SATURDAY AFTERNOON WILL BE NEARLY MOIST ADIABATIC DUE
TO THE COLD TEMPERATURES ALOFT. IF THE SYSTEM TAKES ITS TIME
MOVING ACROSS COLORADO...SIMILAR TO THE ECMWF SOLUTION...THEN IT
WILL BE ABLE TO PRODUCE SNOW AMOUNTS HEAVIER THAN WHAT THE ECMWF
CONTAINS. THE TIMING OF THE GFS AND NAM SOLUTIONS MAY WELL END UP
BEING TOO FAST AS THE SYSTEM ALREADY LOOKS LIKE IT IS READY TO
CUTOFF FROM THE NORTHERN STREAM IN THE NEXT 24 TO 36 HOURS. GIVEN
ALL THE UNCERATINTY...IT IS TOO EARLY TO ISSUE ANY HIGHLIGHTS...
BUT THAT MAY CHANGE LATER TODAY OR TONIGHT. ALONG WITH THE UPPER
DYNAMICS OF THE PASSING UPPER LOW ON SATURDAY...IT LOOKS LIKE A
STRONG SURGE OF NORTHERLY SURFACE WINDS WILL DEVELOP SATURDAY
AFTERNOON ON THE BACK SIDE OF THE STORM. HAVE ADDED AREAS OF
BLOWING SNOW TO THE SATURDAY AFTERNOON AND EVENING FORECAST.
FOR SUNDAY THROUGH TUESDAY...MODELS SHOW COLORADO UNDER NORTHWEST
FLOW WITH WARMER TEMPERATURES AND DRIER CONDITIONS. TEMPERATURE
FORECASTS FOR THESE DAYS IS GOING TO BE VERY DEPENDENT ON HOW MUCH
SNOW FALLS DURING THE SATURDAY THROUGH SUNDAY PERIOD. FOR THE TIME
BEING...WILL KEEP THIS PART OF THE FORECAST VERY GENERAL.
AVIATION...VFR THRU TONIGHT. WK SFC LOW PRES WILL LIKELY REMAIN
WEST OF THE AIRPORT THRU THIS AFTN. OVERALL THE HRRR AND RAP
KEEP WINDS LIGHT SSW THRU LATE MORNING AND THEN GRADUALLY SHIFTTHEN
MORE ELY BY EARLY AFTN. THE ELY WINDS ARE FCST TO STAY IN PLACE AT
LEAST THRU 23Z BEFORE BECOMING MORE SELY BY 01Z. WINDS WILL THEN
GRADUALLY BECOME DRAINAGE BY 03Z AND CONTINUE THAT WAY OVERNIGHT.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...RTG
LONG TERM....99
AVIATION...RTG
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
408 AM MST WED MAR 6 2013
.SHORT TERM...SWLY FLOW ALOFT WILL DEVELOP OVER THE AREA AS THE
UPPER LEVEL RIDGE SHIFTS EAST. SOME HIGHER LEVEL CLOUDS WILL BE
POSSIBLE OTHERWISE IT WILL REMAIN DRY THRU TONIGHT. ONCE AGAIN
HIGH TEMPS THIS AFTN WILL BE THE MAIN ISSUE. SOME DEEPER SNOW
COVER STILL RESIDES OVER SRN WELD...CNTRL AND ERN PORTIONS OF ADAMS
AND ARAPAHOE ALONG WITH ELBERT COUNTIES WHICH WILL AFFECT AFTN
HIGHS IN THESE AREAS AS READINGS MAY NOT GET OUT OF THE 40S.
MEANWHILE NR THE FOOTHILLS LIGHT WLY DOWNSLOPE FLOW WILL DVLP
WHICH MAY ALLOW FOR HIGHS TO REACH THE LOWER 60S OVER THE WRN AND
SRN SUBURBS OF DENVER. THUS WILL SEE QUITE A TEMP DIFFERENCE ALONG
THE FRONT RANGE THIS AFTN. OVER THE PLAINS WHERE NO SNOW COVER
EXISTS WINDS WILL BE MAINLY SELY SO WILL KEEP AFTN HIGHS IN THE
LOWER TO MID 50S EXCEPT OVER SRN LINCOLN COUNTY WHERE LOWER 60S
WILL BE POSSIBLE DUE TO SWLY LOW LVL WINDS. FOR TONIGHT MAY SEE
SOME PATCHY FOG DVLP OVER THE FAR NERN PLAINS AFTER MIDNIGHT.
.LONG TERM...THURSDAY WILL BE DRY AND WARM AS SOUTHWESTERLY FLOW
ALOFT COVERS THE STATE. FRIDAY WILL BE A TRANSITIONAL DAY AS
SOUTHWEST FLOW ALOFT CONTINUES BUT MOISTURE BEGINS INCREASING
AHEAD OF A POTENT UPPER LOW MOVING OVER THE DESERT SOUTHWEST. AND
SATURDAY LOOKS LIKE IT WILL BE THE MOST CRITICAL DAY OF THIS
FORECAST PACKAGE. EACH OF THE SYNOPTIC MODELS SHOW THE STRONG
UPPER LEVEL LOW PRESSURE SYSTEM MOVING ACROSS OR NEAR THE FOUR
CORNERS AREA ON SATURDAY...SETTING UP A SNOW PATTERN FOR NORTHEAST
COLORADO. HOWEVER...AGREEMENT BETWEEN THE MODELS IS FAR FROM
UNANIMOUS. THE GFS IS MORE PROGRESSIVE THAN THE ECMWF AND THE NAM
ONLY GOES OUT TO MIDDAY SATURDAY BUT SHOWS AGREEMENT WITH THE GFS.
PRECIPITATION AMOUNTS ALSO VARY BETWEEN THE DIFFERENT MODELS. THE
NAM SHOWS AN INITIALLY DRY SWATH OF AIR MOVING ACROSS THE EASTERN
PLAINS WITH THE EJECTING UPPER LOW...WHILE THE GFS GENERATES
COPIOUS AMOUNTS OF SNOWFALL. THE ECMWF SHOWS ONLY LIGHT TO
MODERATE SNOW AMOUNTS THROUGH SATURDAY NIGHT. NEEDLESS TO
SAY...MANY QUESTIONS STILL REMAIN ON HOW BIG THIS STORM IS GOING
TO BE. THE STORM SYSTEM...WHICH IS CURRENTLY DEVELOPING OFF THE
COAST OF OREGON IS GOING TO CONTAIN A LOT OF COLD AIR ALOFT AND
WILL ALSO ENCOUNTER A GOOD SHOT OF LOW LEVEL MOISTURE FROM THE
GULF OF MEXICO WHEN IT MOVES ACROSS COLORADO. MODEL SOUNDINGS SHOW
LAPSE RATES SATURDAY AFTERNOON WILL BE NEARLY MOIST ADIABATIC DUE
TO THE COLD TEMPERATURES ALOFT. IF THE SYSTEM TAKES ITS TIME
MOVING ACROSS COLORADO...SIMILAR TO THE ECMWF SOLUTION...THEN IT
WILL BE ABLE TO PRODUCE SNOW AMOUNTS HEAVIER THAN WHAT THE ECMWF
CONTAINS. THE TIMING OF THE GFS AND NAM SOLUTIONS MAY WELL END UP
BEING TOO FAST AS THE SYSTEM ALREADY LOOKS LIKE IT IS READY TO
CUTOFF FROM THE NORTHERN STREAM IN THE NEXT 24 TO 36 HOURS. GIVEN
ALL THE UNCERATINTY...IT IS TOO EARLY TO ISSUE ANY HIGHLIGHTS...
BUT THAT MAY CHANGE LATER TODAY OR TONIGHT. ALONG WITH THE UPPER
DYNAMICS OF THE PASSING UPPER LOW ON SATURDAY...IT LOOKS LIKE A
STRONG SURGE OF NORTHERLY SURFACE WINDS WILL DEVELOP SATURDAY
AFTERNOON ON THE BACK SIDE OF THE STORM. HAVE ADDED AREAS OF
BLOWING SNOW TO THE SATURDAY AFTERNOON AND EVENING FORECAST.
FOR SUNDAY THROUGH TUESDAY...MODELS SHOW COLORADO UNDER NORTHWEST
FLOW WITH WARMER TEMPERATURES AND DRIER CONDITIONS. TEMPERATURE
FORECASTS FOR THESE DAYS IS GOING TO BE VERY DEPENDENT ON HOW MUCH
SNOW FALLS DURING THE SATURDAY THROUGH SUNDAY PERIOD. FOR THE TIME
BEING...WILL KEEP THIS PART OF THE FORECAST VERY GENERAL.
&&
.AVIATION...VFR THRU TONIGHT. WK SFC LOW PRES WILL LIKELY REMAIN
WEST OF THE AIRPORT THRU THIS AFTN. OVERALL THE HRRR AND RAP
KEEP WINDS LIGHT SSW THRU LATE MORNING AND THEN GRADUALLY SHIFTTHEN
MORE ELY BY EARLY AFTN. THE ELY WINDS ARE FCST TO STAY IN PLACE AT
LEAST THRU 23Z BEFORE BECOMING MORE SELY BY 01Z. WINDS WILL THEN
GRADUALLY BECOME DRAINAGE BY 03Z AND CONTINUE THAT WAY OVERNIGHT.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...RPK
LONG TERM....DANKERS
AVIATION...RPK
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
958 PM EST THU MAR 7 2013
.SYNOPSIS...
AN UPPER LEVEL DISTURBANCE WILL SLIDE ACROSS THE AREA OVERNIGHT INTO
FRIDAY MORNING. HIGH PRESSURE WILL GRADUALLY BUILD INTO THE REGION
ON SATURDAY, SETTLE OVER THE AREA ON SUNDAY AND THEN SLIDE
OFFSHORE. A LOW PRESSURE SYSTEM WILL MOVE IN FROM THE WEST EARLY
IN THE WEEK, DRAGGING A COLD FRONT ACROSS THE AREA ON TUESDAY. A
SECONDARY FRONT MAY CROSS THE REGION WEDNESDAY NIGHT INTO EARLY
THURSDAY. HIGH PRESSURE WILL THEN BUILD IN FROM THE WEST FOR
THURSDAY.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
WHILE NONE OF THE MODELS HAD THE BANDED PRECIPITATION SPOT ON, THE
GFS OVERALL LOOKED CLOSER IN THE 6 HR PERIOD ENDING AT 00Z. HARD
TO SAY COMPLETELY BUT THE GFS LOOKED BEST OVERALL WITH THE AREAL
EXTENT AND AMOUNTS EXCEPT FOR CAPE COD WHERE THE WRF-NMMB WAS
BETTER. THE 500MB INITIALIZATION OF THE 00Z WRF-NMMB WAS A BIT TOO
STRONG WITH THE 500MB FEATURES. THE LATEST RUN STARTS ENHANCING
PRECIPITATION EAST OF BOSTON AND THEN PIVOTS IT INTO NEW JERSEY
LATE TONIGHT AND ON FRIDAY MORNING. RIGHT NOW THE IR CLOUDS ARE
WARMING APPROACHING MASSACHUSETTS AND THEIR SFC VSBYS HAVE YET TO
DROP. SO NOT CONFIDENT ABOUT THAT ENHANCED PCPN WORKING TO THAT
EXTENT TO MAKE ANY SIGNIFICANT CHANGES.
OTHERWISE THE 23Z HRRR LOOKED PRETTY GOOD WITH THE OVERALL RADAR
DEPICTION AND THEY PIVOT PCPN INTO NEW JERSEY OVERNIGHT. NEAREST
BAND HAS NOT DROPPED VSBYS MUCH IN NYC. SO THE POP DISTRIBUTION
WAS ANGLED SLIGHTLY MORE NNW TO SSE THAN THE PREVIOUS PACKAGE.
ACCUMS BASED ON SPOTTER REPORTS AND TRAFFIC CAMS SEEM TO BE
MAINLY IN NORTHWEST NEW JERSEY. FARTHER SOUTH, WHILE SNOW HAS
STARTED TO FALL, TEMPERATURES ARE STILL ABOVE FREEZING. DEW POINTS
THOUGH ARE DROPPING AND WOULD EXPECT THE COATINGS AND
ACCUMULATIONS TO START SPREADING SOUTH.
THE GFS MID LEVEL QVEC CONVERGENCE WHICH ALSO WAS ALIGNING WELL
WITH THE MORE ENHANCED ECHOES HAVE THE CORE MOVE THROUGH OUR CWA
AROUND 12Z. SO IF THERE IS AN AREA OF CONCERN ABOUT GETTING TO
ADVISORY LEVELS WOULD THINK MIDDLESEX, MONMOUTH AND OCEAN. FOR NOW
WE ISSUED AN SPS ABOUT THE SNOW COMING IN TOWARD MORNING AND WILL
SEE WHAT THE REST OF GUIDANCE SUITE SHOWS.
WE REALLY DID NOT CHANGE TEMPERATURES MUCH, THEY LOOKED CLOSE.
SOME UPWARD ADJUSTMENTS ON DEW POINTS WERE MADE.
THE SECOND MID LEVEL WILL DROP DOWN FROM WRN NY THIS EVENING TO
NEAR DOV BY DAYBREAK. THIS TIME, THE NAM HAS A LITTLE BIT OF
COMPANY IN THIS PERIOD WITH THE MID LEVEL DYNAMICS, THE LOWER
LEVEL FRONTOGENESIS AND THE MODEST TROWAL THAT PASS ACROSS US. WE
ALREADY HAD AREAS OF LIGHT PRECIPITATION (MAINLY RAIN) OVER THE
NORTHEASTERN HALF OF THE AREA, SO FOR TONIGHT WE BLENDED THE
ECMWF, NAM AND GFS TO PRECIPITATION TO ARRIVE AT POPS THAT RANGE
FROM SLIGHT CHANCE SOUTHWEST TO CATEGORICAL NORTHEAST.
PRECIPITATION SHOULD CHANGE TO SNOW FROM NORTH TO SOUTH ACROSS THE
AREA WHERE IT FALLS. THE QPF FORECAST IS NOT TERRIBLY ROBUST,
SINCE NOT A LOT OF MOISTURE COMES WITH THIS SYSTEM. SNOWFALL
AMOUNTS TONIGHT ARE FORECAST TO RANGE FROM UP TO FIVE INCHES ACROSS
SUSSEX AND MORRIS COUNTIES TO LESS THAN AN INCH NEAR AND SOUTH OF
THE I195 CORRIDOR OVER NJ, DE AND MD AND NEAR AND SOUTH OF A TTN
TO ABE LINE OVER PA. WE WENT A LITTLE ON THE COOLER SIDE OF THE
RANGE OF STAT GUIDANCE WITH THE MID LEVEL LOW DROPPING THROUGH THE
AREA AND WITH PRECIPITATION EXPECTED OVER MUCH OF THE AREA. THE
STEADY NORTHWEST FLOW WILL CONTINUE, AND MAY WELL KICK UP A BIT
TOWARD DAYBREAK.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH 6 PM FRIDAY/...
THE MID LEVEL LOW WILL MOVE SOUTHEAST AND AWAY FROM THE AREA ON
FRIDAY, AND PRECIPITATION WILL END FROM WEST TO EAST IN RESPONSE.
NORTHEASTERN AND EAST CENTRAL AREAS WILL SEE A LITTLE BIT OF
ADDITIONAL SNOW, BUT WE WILL BE DEALING WITH A MARCH SUN ANGLE THAT
WILL TAMP DOWN ANY MORNING ACCUMULATIONS. WE END UP MAINTAINING THE
ADVISORY OVER SUSSEX AND MORRIS COUNTIES AND NOT EXPANDING IT. THERE
DOES NOT APPEAR TO BE ANY WINDEX ISSUE OR ANY LAKE EFFECT ISSUE. WE
ARE IN THE MIDDLE TO LOW END OF STAT GUIDANCE ON TEMPERATURES.
EXPECT ANOTHER BLUSTERY DAY.
&&
.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
THE 500MB LOW STARTS TO MOVE OFF TO THE EAST BY LATE FRIDAY. AS THE
LOW MOVES EASTWARD, WE WILL START TO SEE RIDGING OCCUR IN THE MID
LEVELS, WHICH INDICATES A WARMING TREND INTO THE EXTENDED PERIOD
ACROSS OUR REGION. ANOTHER MID LEVEL SYSTEM, DEVELOPS EARLY IN THE
WEEK ACROSS THE CENTRAL UNITED STATES AND WE START TO SEE TROUGHING
MOVE TOWARD THE EAST COAST ONCE AGAIN. THE MID LEVEL TROUGH DEEPENS
AND MOVES ACROSS OUR REGION AROUND MIDWEEK. A MORE ZONAL FLOW IS
EXPECTED TO DEVELOP CLOSER TO THE FOLLOWING WEEKEND.
AT THE SURFACE, THE STRONG LOW PRESSURE SYSTEM WILL CONTINUE TO PULL
OFF TOWARDS THE EAST, ALLOWING HIGH PRESSURE TO BUILD INTO THE
MID-ATLANTIC REGION OVER THE WEEKEND. THE HIGH BUILDS IN FROM THE
WEST ON SATURDAY BEFORE SLIDING ACROSS THE AREA ON SUNDAY,
EVENTUALLY MOVING OFFSHORE BY LATE SUNDAY NIGHT. EXPECT DRY
CONDITIONS THROUGH EARLY MONDAY AS THE HIGH AT THE SURFACE DOMINATES
THE WEATHER ACROSS THE AREA. AS DRIER AIR MAKES ITS WAY INTO THE
AREA, WE SHOULD LESS CLOUDS DEVELOP.
THE PREVIOUSLY MENTIONED 500MB RIDGE WILL ALLOW FOR WARMING TO
OCCUR. A SOUTHERLY FLOW DEVELOPS AT THE SURFACE ON SUNDAY AS THE
SURFACE HIGH MOVES OFFSHORE AND THIS WILL JUST INCREASE THE WARMING
ACROSS THE REGION. WE WILL SEE TEMPERATURES RISE WELL ABOVE NORMAL
FOR AT LEAST A FEW DAYS. DAYTIME TEMPERATURES WILL BE IN THE UPPER
40S TO LOWER 50S ON SATURDAY BUT WILL RISE INTO THE MID 50S ON
SUNDAY.
THE HIGH SLIDES OFFSHORE SUNDAY NIGHT AND LOW PRESSURE OVER THE
MIDWEST STARTS TO MOVE EASTWARD. CLOUDS WILL BEGIN TO INCREASE LATE
SUNDAY AND CONTINUE TO INCREASE THROUGH MONDAY. THE LOW MOVES
NORTHEASTWARD AND UP INTO NEW ENGLAND, DRAGGING A COLD FRONT INTO
OUR AREA ON MONDAY NIGHT. THE FRONT EXTENDS WELL INTO THE SOUTHERN
STATES AND LOOKS TO GATHER SOME OF ITS MOISTURE ALL THE WAY FROM THE
GULF. A SECOND LOW DEVELOPS ALONG THE FRONTAL BOUNDARY AND THEN
MOVES NORTHEASTWARD. THE MODELS DISAGREE ON JUST HOW FAST THE
BOUNDARY MOVES TO THE EAST AND AS A RESULT THE SECOND LOW MAY END UP
REMAINING TO THE SOUTH OF THE AREA AS IT MOVES NORTHEASTWARD.
THEREFORE, WE OPTED TO MAKE FEW CHANGES TO THE CURRENT TIMING IN THE
FORECAST. EITHER WAY, IT DOES APPEARS THAT THERE WILL BE RAIN ACROSS
THE REGION MONDAY NIGHT AND TUESDAY AS THE FRONT CROSSES THE AREA.
TEMPERATURES ALSO LOOK TO REMAIN WARM ENOUGH TO KEEP THE
PRECIPITATION PRIMARILY RAIN ACROSS THE REGION.
THE SURFACE LOW MOVES OFF INTO NEW ENGLAND ON TUESDAY AND BEGINS TO
INTENSIFY. AS THE LOW DEEPENS, WE WILL START TO GET A PUSH OF COLD
AIR INTO THE REGION ON THE CYCLONIC FLOW, BOTH AT THE SURFACE AND
ALOFT. SHOULD THE NORTHWEST FLOW BE STRONG ENOUGH, WE CAN NOT RULE
OUT THAT SOME LAKE EFFECT SNOW WILL MAKE IT INTO OUR NORTHWEST ZONES
WHERE TEMPERATURES WILL REMAIN IN THE UPPER 30S TO LOWER 40S,
ESPECIALLY ACROSS THE HIGHER TERRAIN. IF THE FLOW IS STRONG ENOUGH A
FEW SPRINKLES OR LIGHT SHOWERS MAY MAKE IT FURTHER SOUTH AND
EASTWARD, WHERE TEMPERATURES WILL LIKELY RISE INTO THE UPPER 40S TO
LOWER 50S. HIGH PRESSURE WILL THEN BUILD INTO AREA FOR THURSDAY.
&&
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
THE 00Z TAFS ARE FORECASTING MAINLY VFR CONDITIONS AT KILG WITH
THE MOST PROLONGED IFR CONDITIONS AT KTTN. GENERICALLY SPEAKING
BECAUSE OF THE SNOW NERN CWA AIRPORTS AND TERMINALS WILL BE
IMPACTED THE GREATEST AND LONGEST WITH PROBABLY IFR CONDITIONS
AND SOUTHWESTERN AIRPORTS AND TERMINALS THE LEAST.
FOR TONIGHT EXPECT CONDITIONS TO DROP DOWN TO AT LEAST MVFR (BOTH
CIGS AND VSBYS) AS PCPN CONTINUES TO WRAPAROUND. MOST OF THESE LOWER
CONDITIONS SHOULD OCCUR AFTER 05Z. THERE COULD BE SOME RAIN MIXED
IN WITH THE PRECIPITATION AROUND THE KPHL METRO AIRPORTS, BUT THE
TREND WILL BE TOWARD SNOW AND THE CHANCES INCREASE AS THE NIGHT
PROGRESSES. WE DID NOT CARRY ANY WIND GUSTS, A STEADY NORTH WIND
AT 10 TO 15 KNOTS.
ON FRIDAY MORNING SNOW OR SNOW SHOWERS (OR CHANCES) SHOULD BE SLOWLY
ENDING FROM KILG AND KRDG EASTWARD. MVFR TO IFR CONDITIONS
(MAINLY DUE TO VSBY) SHOULD BE IMPROVING TO VFR AS THE MORNING
PROGRESSES. SNOW CHANCES AT KACY MIGHT LIGHTER INTO THE EARLY
AFTERNOON. THE NORTH TO NORTHWEST WINDS SHOULD BECOME BLUSTERY
AGAIN WITH PEAK GUSTS AT AROUND 30 KNOTS. CIGS WILL BE VFR, BUT WE
ARE NOT EXPECTING TO LOSE THEM UNTIL FRIDAY NIGHT.
OUTLOOK...
FRIDAY NIGHT...MAINLY VFR CONDITIONS EXPECTED. NORTHERLY WINDS
AROUND 10 TO 15 KNOTS WITH GUSTS UP TO 20 KNOTS, DIMINISHING SOME
OVERNIGHT.
SATURDAY AND SUNDAY...VFR CONDITIONS EXPECTED. NORTH TO NORTHEAST
WINDS AROUND 10 KNOTS ON SATURDAY, DIMINISHING OVERNIGHT. WINDS
BECOME SOUTH TO SOUTHEAST ON SUNDAY, AROUND 5 TO 10 KNOTS.
INCREASING CLOUDINESS, ESPECIALLY SUNDAY NIGHT, BUT VFR CONDITIONS
EXPECTED TO CONTINUE.
MONDAY...MAINLY VFR CONDITIONS EXPECTED. WINDS WILL BE SOUTHERLY
AROUND 10 KNOTS.
MONDAY NIGHT THROUGH TUESDAY...VFR CONDITIONS WILL DETERIORATE TO
MVFR, POSSIBLY IFR, WITH RAIN. SOUTH WINDS WILL LIGHTEN OVERNIGHT
BEFORE BECOMING WESTERLY ON TUESDAY. CONDITIONS WILL BEGIN TO
IMPROVE THROUGH THE DAY ON TUESDAY.
&&
.MARINE...
GALES HAD SUBSIDED OVER THE WATERS EARLY THIS AFTERNOON. ALTHOUGH
THE SECONDARY SYSTEM IS EXPECTED TO CAUSE GALES TO DEVELOP AGAIN
OVERNIGHT TONIGHT, WE CARVED OUT A PERIOD OF SUB-GALE FORCE WINDS
IN THE FORECAST AND RECONFIGURED THE GALE WARNING TO START OVER
OUR WATERS AFTER MIDNIGHT. WE RUN IT THROUGH FRIDAY OVER ALL
WATERS.
OUTLOOK...
GALES WILL CONTINUE THROUGH 06Z/SAT (1AM SAT) ON THE OCEAN.
LOW PRESSURE WILL CONTINUE TO PUSH EASTWARD FRIDAY NIGHT AS HIGH
PRESSURE GRADUALLY BUILDS IN FROM THE WEST. THE GRADIENT BETWEEN THE
TWO SYSTEMS WILL KEEP THE WINDS GUSTING TO GALE FORCE FRIDAY NIGHT.
THE GRADIENT STARTS TO WEAKEN OVERNIGHT AND THE WINDS SHOULD DROP
BELOW GALE FORCE BY AROUND MIDNIGHT OR SO ACROSS THE OCEAN. ONCE THE
GALES COME DOWN, SMALL CRAFT ADVISORIES WILL BE NEEDED AS WINDS WILL
REMAIN GUSTY THROUGH SATURDAY.
THE HIGH PRESSURE SLIDES OVER THE REGION ON SUNDAY AND THEN MOVES
OFFSHORE BY SUNDAY NIGHT. SEAS WILL REMAIN ABOVE 5 FEET THROUGH THE
WEEKEND AND WILL MAINLY CONTINUE TO REMAIN NEAR OR ABOVE 5 FEET INTO
EARLY NEXT WEEK.
&&
.TIDES/COASTAL FLOODING...
DECIDED TO CANCEL THE FLOOD WARNING FOR THE LOWER BAY AND OCEANFRONT
BASED ON CURRENT AND PROJECTED DEPARTURES. A LOT OF THE GAUGES ON
THE OCEANFRONT STRUGGLED TO REACH LOW-END MODERATE WITH THIS
MORNINGS HIGH TIDE, WHICH WAS THE HIGHER OF THE TWO TODAY. WITH THIS
LATEST HIGH TIDE WE BARELY REACHED MINOR TIDAL AS THE SURFACE WINDS
BACKED MORE TOWARDS THE NORTHWEST AS THE CENTER OF THE LOW PRESSURE
PULLS FURTHER TO THE NORTHEAST.
CURRENTLY RUNNING AROUND A 2 FOOT DEPARTURE IN MOST PLACES AND IF
THAT WERE TO REMAIN CONSISTENT THROUGH FRIDAY MORNINGS HIGH TIDE
CYCLE WOULD YIELD WIDESPREAD MINOR TIDAL FLOODING. WE SHOULD
CONTINUE TO HAVE MORE OF AN OFFSHORE FLOW TONIGHT AND TOMORROW
MORNING WHICH WOULD KEEP DEPARTURES STEADY OR SLOWLY FALLING. THAT
BEING SAID THE WARNING HAS BEEN REPLACED WITH AN ADVISORY. WE WILL
CONTINUE TO MONITOR THE TIDES OVER THE SUBSEQUENT SHIFTS AND MAKE
ADJUSTMENTS AS NEEDED.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...WINTER WEATHER ADVISORY UNTIL NOON EST FRIDAY FOR NJZ001-008.
COASTAL FLOOD ADVISORY UNTIL 9 AM EST FRIDAY FOR NJZ012>014-
020>027.
DE...COASTAL FLOOD ADVISORY UNTIL 9 AM EST FRIDAY FOR DEZ002>004.
MD...NONE.
MARINE...GALE WARNING FROM 1 AM FRIDAY TO 1 AM EST SATURDAY FOR
ANZ450>455.
GALE WARNING FROM 1 AM TO 6 PM EST FRIDAY FOR ANZ430-431.
&&
$$
SYNOPSIS...MEOLA
NEAR TERM...DELISI/GIGI
SHORT TERM...DELISI
LONG TERM...MEOLA
AVIATION...GIGI/MEOLA
MARINE...DELISI/MEOLA
TIDES/COASTAL FLOODING...HEAVENER
AREA FORECAST DISCUSSION...UPDATE
NWS TAMPA BAY RUSKIN FL
545 AM EST WED MAR 6 2013
.UPDATE...
LOW LEVEL FOCUS ALONG A FAST MOVING COLD FRONT HAS RESULTED IN MORE
ORGANIZATION TO THE SHOWER ACTIVITY AS IT PROCEEDS SOUTH OF THE
TAMPA BAY AREA. THE AREA OF SHOWERS IS STILL RATHER NARROW AND
MOVING FAST...SO ANY PERIOD OF RAIN/SHOWERS WILL BE BRIEF EARLY THIS
MORNING FOR THE SOUTHERN HALF OF THE AREA. HOWEVER...HAVE RAISED
RAIN CHANCES TO LIKELY FOR THESE ZONES TO ACCOUNT FOR THE MORE SOLID
BAND NOW SEEN ON REGIONAL RADAR. THIS BAND OF SHOWERS AND THE
ASSOCIATED COLD FRONT WILL CONTINUE TO RAPIDLY PUSH SOUTH THE NEXT
COUPLE OF HOURS AND BE SOUTH OF FT MYERS...AND OUT OF THE FORECAST
AREA BY AROUND 10AM.
&&
.SYNOPSIS...
08Z WATER VAPOR AND H4 RAP ANALYSIS SHOWING A FAIRLY AMPLIFIED UPPER
LEVEL PATTERN ACROSS THE CONUS EARLY THIS MORNING. LARGE LONGWAVE
RIDGING IS NOW IN PLACE ACROSS MUCH OF THE INTER-MOUNTAIN WEST AND
CENTRAL PLAINS WITH THE DOWNSTREAM FLOW DROPPING QUICKLY INTO A
SHARP TROUGH OVER THE EASTERN STATES. THIS TROUGH IS ANCHORED BY A
TIGHT/POTENT UPPER LEVEL LOW EXITING THE TN VALLEY TOWARD THE
MID-ATLANTIC COAST. THIS ENERGY AND ASSOCIATED SURFACE FEATURE WILL
BRING A SIGNIFICANT SNOWFALL TO PARTS OF THE MID-ATLANTIC THROUGH
WEDNESDAY. OUR FORECAST AREA RESIDES AT THE BASE OF THIS
TROUGH...FAR REMOVED FROM ANY SIGNIF MID/UPPER LEVEL SYNOPTIC/QG
FORCING. WV IMAGERY SHOWS A NARROW BAND OF MOISTURE DROPPING SOUTH
ACROSS THE PENINSULA FOLLOWED QUICKLY BY MARKED DRYING/SUBSIDENCE IN
THE WAKE OF THE PASSING SHORTWAVE JUST TO OUR NORTH. THIS DRYING
WILL OVERSPREAD OUR SKIES THROUGH THE DAY. THERE IS ALSO QUITE A
SURGE OF COLD AIR ABOVE THE SURFACE ASSOCIATED WITH THIS SYSTEM TO
OUR NORTH...HOWEVER THE MAIN SURGE OF THIS AIRMASS WILL BE TOWARD
THE GA/CAROLINA COAST AND PREVENT THE ARRIVAL OF ANOTHER AIRMASS
COMPARABLE TO WHAT WAS SEEN THIS PREVIOUS WEEKEND.
AT THE SURFACE...WELL DEFINED COLD FRONT IS QUICKLY DROPPING TO THE
SOUTHEAST INTO THE NORTH-CENTRAL FL PENINSULA. JUST ENOUGH MOISTURE
IN THE LOW LEVELS AND FRONTAL FOCUS THIS MORNING TO SUPPORT A NARROW
BAND OF BROKEN (MAINLY LIGHT) SHOWERS. WINDS PICK UP QUICKLY FROM
THE NW IN THE WAKE OF THE FRONT...AND IT WILL LIKELY BE FAIRLY
EVIDENT BY THIS SURGE OF WIND WHEN THE FRONT PASSES ANY GIVEN
LOCATION THROUGH THE MORNING HOURS.
&&
.SHORT TERM (TODAY THROUGH FRIDAY)...
TODAY...COLD FRONT WILL QUICKLY DROP SOUTH THROUGH AND OUT OF THE
FORECAST AREA THIS MORNING. CURRENT GRIDS SHOW THE FRONT PASSING
SOUTH OF FT. MYERS BY LATE MORNING. THERE WILL BE A CHANCE OF A
BRIEF SHOWER OR SPRINKLE AHEAD OF THIS FRONT TO THE SOUTH OF TAMPA
BAY THROUGH MID MORNING...HOWEVER ANY RAINFALL WILL NOT AMOUNT TO
MUCH. BY SUNRISE...THE FRONT LOOKS TO HAVE ALREADY PASSED TAMPA BAY
AND POINTS NORTH TAKING ANY SCATTERED SHOWERS SOUTHWARD WITH IT.
THEREFORE...FORECAST WILL SHOW SKIES CLEARING FROM NORTH TO SOUTH
THROUGH THE DAY WITH MOST OF THE REGION SEEING ABUNDANT SUNSHINE BY
EARLY AFTERNOON. EXPECTING A BREEZY/GUSTY DAY WITH NW WINDS BEHIND
THE FRONT...AND A LAKE WIND ADVISORY HAS BEEN ISSUED FOR THIS
MORNING THROUGH EARLY EVENING. THE MOST EVIDENT CAA WILL BE NORTH OF
THE I-4 CORRIDOR WHERE HIGH TEMPS WILL HOLD IN THE LOW/MID 60S.
SOUTH OF I-4 TEMPS WILL MAKE A RUN AT 70. COOLEST TEMPS WILL BE
ALONG THE COAST FROM MANATEE COUNTY NORTHWARD WITH FLOW OFF THE
RELATIVELY COOLER SHELF WATERS. THE STRONG NW WINDS WILL ALSO BRING
BUILDING SWELL/SURF FOR AREA BEACHES AND WILL RESULT IN A
MODERATE/ELEVATED RISK OF RIP CURRENTS FROM PINELLAS COUNTY
SOUTHWARD. THIS ELEVATED RISK SHOULD LINGER INTO THURSDAY MORNING
BEFORE THE SWELL AND ONSHORE WIND COMPONENT BEGINS TO DECLINE.
TONIGHT...A CHILLY MARCH NIGHT IN STORE IN THE DRY POST-FRONTAL
ENVIRONMENT. SOME OF THE STATISTICAL GUIDANCE IS SHOWING READINGS A
COUPLE OF DEGREES BELOW FREEZING FOR THE INTERIOR NATURE COAST.
HOWEVER...STATISTICAL GUIDANCE IS ALMOST ALWAYS AT LEAST SEVERAL
DEGREES TOO COLD WITH ADVECTION SCENARIOS ON THE FIRST NIGHT BEHIND
FRONTS. THERE IS NO DOUBT THAT IT WILL BE A COLD (MIDDLE/UPPER 30S
COMMON AWAY FROM THE COAST...BUT AT THIS TIME WILL KEEP TEMPERATURES
JUST ABOVE FREEZING...EVEN UP TOWARD CITRUS AND LEVY COUNTIES. ALSO
SINCE THE GRADIENT WILL STAY UP AND OVERNIGHT DEWPOINT DEPRESSIONS
ARE FORECAST TO BE 5-8 DEGREES...THE THREAT OF FROST APPEARS LOW.
EACH OF THESE FACTORS WILL NEED TO BE RE-EVALUATED DURING THE DAY.
THURSDAY/THURSDAY NIGHT...
A BROAD DEEP LAYER NORTHWEST FLOW WILL BE IN PLACE ON THE BACKSIDE
OF LONGWAVE TROUGHING OFF THE ATLANTIC SEABOARD. THIS FLOW WILL KEEP
A STEADY SUPPLY OF DRY AIR ARRIVING FROM THE NORTH. MAY SEE A BOUT
OF HIGHER CIRRUS LATER THURSDAY/THURSDAY EVENING OVER THE NORTHERN
HALF OF THE STATE ASSOCIATED WITH A WEAK PASSING SHORTWAVE...BUT
OTHERWISE SKIES LOOK TO BE MOSTLY CLEAR. WINDS WILL BE LESS GUSTY
FOR THURSDAY AS SURFACE RIDGING CONTINUES TO BUILD IN FROM THE
NORTHWEST. HIGH TEMPS WILL GENERALLY REACH THE UPPER 60S TO NEAR 70
NORTH AND THE LOWER/MID 70S SOUTH. BEACH TEMPS WILL LIKELY AGAIN BE
HELD IN THE 60S WITH AT LEAST SOME ONSHORE FLOW COMPONENT...
ESPECIALLY NORTH OF LEE/CHARLOTTE COUNTIES. WIDESPREAD 40S THURSDAY
NIGHT FOR LOW TEMPS...WITH SOME UPPER 30S FOR THE NATURE COAST.
FRIDAY...
"CHAMBER OF COMMERCE" WEATHER TO END THE WORK WEEK AFTER A COOL
EARLY MORNING START. STACKED RIDGING WILL BE BUILDING EASTWARD
ACROSS THE GULF TOWARD THE AREA CONTINUING A FORECAST OF ABUNDANT
SUNSHINE AND WARMING TEMPERATURES.
&&
.LONG TERM (FRIDAY NIGHT THROUGH NEXT TUESDAY)...
THE PERIOD BEGINS WITH DEEP LAYER RIDGING FROM THE GULF TO THE
GREAT LAKES. THROUGH THE WEEKEND THIS RIDGING SLOWLY SHIFTS EAST
ACROSS THE AREA WITH DRY AND SEASONABLE CONDITIONS AS WINDS VEER
FROM NORTH TO SOUTHEAST AND MAY BE ROBUST AT TIMES ON THE GULF.
BY MON THE RIDGING WILL BE EAST OF FL AS AN UPPER LOW/TROUGH
WITH AN ATTENDANT SURFACE FRONT MOVES INTO THE MID CONUS. THIS
SYSTEM CONTINUES EAST TUE...PUSHING THE FRONT DOWN THE STATE WITH
INCREASING CLOUDS AND A SLIGHT CHANCE OF SHOWERS SPREADING
SOUTHWARD. THE LATEST GFS AND ECMWF GUIDANCE WERE FAIRLY CONSISTENT
THROUGH THE PERIOD BUT BEGIN TO DIVERGE TUE WITH THE ECMWF SLOWER
THAN THE GFS IN MOVING THE FRONT ACROSS FL.
&&
.AVIATION...
APPROACHING FRONT WILL SPREAD SHRA/VCSH UNDER BKN MVFR CIGS
SOUTHWARD...BEGINNING AT 09Z IN THE NORTH AND ENDING AROUND 18Z IN
THE SOUTH. SOUTH AND SW WINDS SHIFT TO NW AND GUSTY FOR THE LATE
MORNING AND AFTERNOON.
&&
.MARINE...
A COLD FRONT WILL QUICKLY PASS SOUTH THROUGH THE EASTERN GULF OF
MEXICO THIS MORNING. WINDS FROM THE NORTHWEST AND SEAS WILL RAPIDLY
INCREASE TO ADVISORY LEVELS BEHIND THE FRONT AND LINGER THROUGH THE
DAY AND EVENING. LATER TONIGHT...WINDS AND SEAS WILL BEGIN TO
SUBSIDE. WINDS AND SEAS WILL GENERALLY REMAIN BELOW HEADLINE
CRITERIA FROM THURSDAY AFTERNOON THROUGH THE DAYLIGHT HOURS FRIDAY
AS HIGH PRESSURE BUILDS IN FROM THE NORTH. THIS RIDGE SLIDES
EASTWARD FOR THE UPCOMING WEEKEND SETTING UP A GOOD SCENARIO FOR
NOCTURNAL AND EARLY MORNING EASTERLY WIND SURGES. THESE SURGES ARE
CURRENTLY FORECAST TO REACH CAUTIONARY LEVELS BOTH FRIDAY NIGHT AND
SATURDAY NIGHT.
&&
.FIRE WEATHER...
DRY AIR ARRIVING BEHIND A COLD FRONT WILL COMBINE WITH GUSTY NW
WINDS AND ERC VALUES ABOVE 27 TO RESULT IN RED FLAG CONDITIONS FOR
MOST OF THE REGION THIS AFTERNOON. THE ONLY EXCEPTIONS WILL BE NEAR
THE COAST WHERE ONSHORE FLOW SHOULD HELP PREVENT CRITICAL RELATIVE
HUMIDITY LEVELS. SEVERAL HOURS OF CRITICALLY LOW RELATIVE HUMIDITY
APPEAR LIKELY FOR THURSDAY LATE MORNING/AFTERNOON AS WELL.
HOWEVER...LIGHTER WINDS AND CURRENT ERC VALUES BELOW 37 DO NOT
MATCH RED FLAG CRITERIA FOR ANY ZONES. THIS POTENTIAL FOR RED FLAG
CONDITIONS CAN BE RE-EVALUATED THIS AFTERNOON WITH THE ISSUANCE OF
THE NEW ERC VALUES. IF ANY ZONES RISE TO 37 OR HIGHER...WARNINGS
WILL LIKELY BECOME REQUIRED.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 64 43 67 47 / 10 0 0 0
FMY 72 44 71 48 / 30 0 0 0
GIF 68 40 72 44 / 10 0 0 0
SRQ 65 44 67 46 / 20 0 0 0
BKV 64 36 68 38 / 10 0 0 0
SPG 63 49 67 53 / 10 0 0 0
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...LAKE WIND ADVISORY FROM 10 AM THIS MORNING TO 7 PM EST
THIS EVENING FOR CHARLOTTE-CITRUS-DESOTO-HARDEE-
HERNANDO-HIGHLANDS-HILLSBOROUGH-LEE-LEVY-MANATEE-
PASCO-PINELLAS-POLK-SARASOTA-SUMTER.
RED FLAG WARNING FROM NOON TODAY TO 7 PM EST THIS EVENING
FOR CHARLOTTE-CITRUS-DESOTO-HARDEE-HERNANDO-HIGHLANDS-
HILLSBOROUGH-LEE-LEVY-MANATEE-PASCO-POLK-SARASOTA-
SUMTER.
BEACH HAZARDS STATEMENT THROUGH THURSDAY MORNING FOR
CHARLOTTE-HILLSBOROUGH-LEE-MANATEE-PINELLAS-SARASOTA.
GULF WATERS...SMALL CRAFT ADVISORY UNTIL 4 AM EST THURSDAY FOR TARPON
SPRINGS TO SUWANNEE RIVER OUT 20 NM-TARPON SPRINGS TO
SUWANNEE RIVER OUT 20 TO 60 NM.
SMALL CRAFT ADVISORY UNTIL 4 AM EST THURSDAY FOR BONITA
BEACH TO ENGLEWOOD OUT 20 NM-BONITA BEACH TO
ENGLEWOOD OUT 20 TO 60 NM-ENGLEWOOD TO TARPON SPRINGS
OUT 20 NM-ENGLEWOOD TO TARPON SPRINGS OUT 20 TO 60 NM-
TAMPA BAY WATERS.
&&
$$
UPDATE/SYNOPSIS/SHORT TERM/MARINE/FIRE WX...MROCZKA
LONG TERM/AVIATION...RUDE
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
300 AM EST WED MAR 6 2013
.SYNOPSIS...
08Z WATER VAPOR AND H4 RAP ANALYSIS SHOWING A FAIRLY AMPLIFIED UPPER
LEVEL PATTERN ACROSS THE CONUS EARLY THIS MORNING. LARGE LONGWAVE
RIDGING IS NOW IN PLACE ACROSS MUCH OF THE INTER-MOUNTAIN WEST AND
CENTRAL PLAINS WITH THE DOWNSTREAM FLOW DROPPING QUICKLY INTO A
SHARP TROUGH OVER THE EASTERN STATES. THIS TROUGH IS ANCHORED BY A
TIGHT/POTENT UPPER LEVEL LOW EXITING THE TN VALLEY TOWARD THE
MID-ATLANTIC COAST. THIS ENERGY AND ASSOCIATED SURFACE FEATURE WILL
BRING A SIGNIFICANT SNOWFALL TO PARTS OF THE MID-ATLANTIC THROUGH
WEDNESDAY. OUR FORECAST AREA RESIDES AT THE BASE OF THIS
TROUGH...FAR REMOVED FROM ANY SIGNIF MID/UPPER LEVEL SYNOPTIC/QG
FORCING. WV IMAGERY SHOWS A NARROW BAND OF MOISTURE DROPPING SOUTH
ACROSS THE PENINSULA FOLLOWED QUICKLY BY MARKED DRYING/SUBSIDENCE IN
THE WAKE OF THE PASSING SHORTWAVE JUST TO OUR NORTH. THIS DRYING
WILL OVERSPREAD OUR SKIES THROUGH THE DAY. THERE IS ALSO QUITE A
SURGE OF COLD AIR ABOVE THE SURFACE ASSOCIATED WITH THIS SYSTEM TO
OUR NORTH...HOWEVER THE MAIN SURGE OF THIS AIRMASS WILL BE TOWARD
THE GA/CAROLINA COAST AND PREVENT THE ARRIVAL OF ANOTHER AIRMASS
COMPARABLE TO WHAT WAS SEEN THIS PREVIOUS WEEKEND.
AT THE SURFACE...WELL DEFINED COLD FRONT IS QUICKLY DROPPING TO THE
SOUTHEAST INTO THE NORTH-CENTRAL FL PENINSULA. JUST ENOUGH MOISTURE
IN THE LOW LEVELS AND FRONTAL FOCUS THIS MORNING TO SUPPORT A NARROW
BAND OF BROKEN (MAINLY LIGHT) SHOWERS. WINDS PICK UP QUICKLY FROM
THE NW IN THE WAKE OF THE FRONT...AND IT WILL LIKELY BE FAIRLY
EVIDENT BY THIS SURGE OF WIND WHEN THE FRONT PASSES ANY GIVEN
LOCATION THROUGH THE MORNING HOURS.
&&
.SHORT TERM (TODAY THROUGH FRIDAY)...
TODAY...COLD FRONT WILL QUICKLY DROP SOUTH THROUGH AND OUT OF THE
FORECAST AREA THIS MORNING. CURRENT GRIDS SHOW THE FRONT PASSING
SOUTH OF FT. MYERS BY LATE MORNING. THERE WILL BE A CHANCE OF A
BRIEF SHOWER OR SPRINKLE AHEAD OF THIS FRONT TO THE SOUTH OF TAMPA
BAY THROUGH MID MORNING...HOWEVER ANY RAINFALL WILL NOT AMOUNT TO
MUCH. BY SUNRISE...THE FRONT LOOKS TO HAVE ALREADY PASSED TAMPA BAY
AND POINTS NORTH TAKING ANY SCATTERED SHOWERS SOUTHWARD WITH IT.
THEREFORE...FORECAST WILL SHOW SKIES CLEARING FROM NORTH TO SOUTH
THROUGH THE DAY WITH MOST OF THE REGION SEEING ABUNDANT SUNSHINE BY
EARLY AFTERNOON. EXPECTING A BREEZY/GUSTY DAY WITH NW WINDS BEHIND
THE FRONT...AND A LAKE WIND ADVISORY HAS BEEN ISSUED FOR THIS
MORNING THROUGH EARLY EVENING. THE MOST EVIDENT CAA WILL BE NORTH OF
THE I-4 CORRIDOR WHERE HIGH TEMPS WILL HOLD IN THE LOW/MID 60S.
SOUTH OF I-4 TEMPS WILL MAKE A RUN AT 70. COOLEST TEMPS WILL BE
ALONG THE COAST FROM MANATEE COUNTY NORTHWARD WITH FLOW OFF THE
RELATIVELY COOLER SHELF WATERS. THE STRONG NW WINDS WILL ALSO BRING
BUILDING SWELL/SURF FOR AREA BEACHES AND WILL RESULT IN A
MODERATE/ELEVATED RISK OF RIP CURRENTS FROM PINELLAS COUNTY
SOUTHWARD. THIS ELEVATED RISK SHOULD LINGER INTO THURSDAY MORNING
BEFORE THE SWELL AND ONSHORE WIND COMPONENT BEGINS TO DECLINE.
TONIGHT...A CHILLY MARCH NIGHT IN STORE IN THE DRY POST-FRONTAL
ENVIRONMENT. SOME OF THE STATISTICAL GUIDANCE IS SHOWING READINGS A
COUPLE OF DEGREES BELOW FREEZING FOR THE INTERIOR NATURE COAST.
HOWEVER...STATISTICAL GUIDANCE IS ALMOST ALWAYS AT LEAST SEVERAL
DEGREES TOO COLD WITH ADVECTION SCENARIOS ON THE FIRST NIGHT BEHIND
FRONTS. THERE IS NO DOUBT THAT IT WILL BE A COLD (MIDDLE/UPPER 30S
COMMON AWAY FROM THE COAST...BUT AT THIS TIME WILL KEEP TEMPERATURES
JUST ABOVE FREEZING...EVEN UP TOWARD CITRUS AND LEVY COUNTIES. ALSO
SINCE THE GRADIENT WILL STAY UP AND OVERNIGHT DEWPOINT DEPRESSIONS
ARE FORECAST TO BE 5-8 DEGREES...THE THREAT OF FROST APPEARS LOW.
EACH OF THESE FACTORS WILL NEED TO BE RE-EVALUATED DURING THE DAY.
THURSDAY/THURSDAY NIGHT...
A BROAD DEEP LAYER NORTHWEST FLOW WILL BE IN PLACE ON THE BACKSIDE
OF LONGWAVE TROUGHING OFF THE ATLANTIC SEABOARD. THIS FLOW WILL KEEP
A STEADY SUPPLY OF DRY AIR ARRIVING FROM THE NORTH. MAY SEE A BOUT
OF HIGHER CIRRUS LATER THURSDAY/THURSDAY EVENING OVER THE NORTHERN
HALF OF THE STATE ASSOCIATED WITH A WEAK PASSING SHORTWAVE...BUT
OTHERWISE SKIES LOOK TO BE MOSTLY CLEAR. WINDS WILL BE LESS GUSTY
FOR THURSDAY AS SURFACE RIDGING CONTINUES TO BUILD IN FROM THE
NORTHWEST. HIGH TEMPS WILL GENERALLY REACH THE UPPER 60S TO NEAR 70
NORTH AND THE LOWER/MID 70S SOUTH. BEACH TEMPS WILL LIKELY AGAIN BE
HELD IN THE 60S WITH AT LEAST SOME ONSHORE FLOW COMPONENT...
ESPECIALLY NORTH OF LEE/CHARLOTTE COUNTIES. WIDESPREAD 40S THURSDAY
NIGHT FOR LOW TEMPS...WITH SOME UPPER 30S FOR THE NATURE COAST.
FRIDAY...
"CHAMBER OF COMMERCE" WEATHER TO END THE WORK WEEK AFTER A COOL
EARLY MORNING START. STACKED RIDGING WILL BE BUILDING EASTWARD
ACROSS THE GULF TOWARD THE AREA CONTINUING A FORECAST OF ABUNDANT
SUNSHINE AND WARMING TEMPERATURES.
&&
.LONG TERM (FRIDAY NIGHT THROUGH NEXT TUESDAY)...
THE PERIOD BEGINS WITH DEEP LAYER RIDGING FROM THE GULF TO THE
GREAT LAKES. THROUGH THE WEEKEND THIS RIDGING SLOWLY SHIFTS EAST
ACROSS THE AREA WITH DRY AND SEASONABLE CONDITIONS AS WINDS VEER
FROM NORTH TO SOUTHEAST AND MAY BE ROBUST AT TIMES ON THE GULF.
BY MON THE RIDGING WILL BE EAST OF FL AS AN UPPER LOW/TROUGH
WITH AN ATTENDANT SURFACE FRONT MOVES INTO THE MID CONUS. THIS
SYSTEM CONTINUES EAST TUE...PUSHING THE FRONT DOWN THE STATE WITH
INCREASING CLOUDS AND A SLIGHT CHANCE OF SHOWERS SPREADING
SOUTHWARD. THE LATEST GFS AND ECMWF GUIDANCE WERE FAIRLY CONSISTENT
THROUGH THE PERIOD BUT BEGIN TO DIVERGE TUE WITH THE ECMWF SLOWER
THAN THE GFS IN MOVING THE FRONT ACROSS FL.
&&
.AVIATION...
APPROACHING FRONT WILL SPREAD SHRA/VCSH UNDER BKN MVFR CIGS
SOUTHWARD...BEGINNING AT 09Z IN THE NORTH AND ENDING AROUND 18Z IN
THE SOUTH. SOUTH AND SW WINDS SHIFT TO NW AND GUSTY FOR THE LATE
MORNING AND AFTERNOON.
&&
.MARINE...
A COLD FRONT WILL QUICKLY PASS SOUTH THROUGH THE EASTERN GULF OF
MEXICO THIS MORNING. WINDS FROM THE NORTHWEST AND SEAS WILL RAPIDLY
INCREASE TO ADVISORY LEVELS BEHIND THE FRONT AND LINGER THROUGH THE
DAY AND EVENING. LATER TONIGHT...WINDS AND SEAS WILL BEGIN TO
SUBSIDE. WINDS AND SEAS WILL GENERALLY REMAIN BELOW HEADLINE
CRITERIA FROM THURSDAY AFTERNOON THROUGH THE DAYLIGHT HOURS FRIDAY
AS HIGH PRESSURE BUILDS IN FROM THE NORTH. THIS RIDGE SLIDES
EASTWARD FOR THE UPCOMING WEEKEND SETTING UP A GOOD SCENARIO FOR
NOCTURNAL AND EARLY MORNING EASTERLY WIND SURGES. THESE SURGES ARE
CURRENTLY FORECAST TO REACH CAUTIONARY LEVELS BOTH FRIDAY NIGHT AND
SATURDAY NIGHT.
&&
.FIRE WEATHER...
DRY AIR ARRIVING BEHIND A COLD FRONT WILL COMBINE WITH GUSTY NW
WINDS AND ERC VALUES ABOVE 27 TO RESULT IN RED FLAG CONDITIONS FOR
MOST OF THE REGION THIS AFTERNOON. THE ONLY EXCEPTIONS WILL BE NEAR
THE COAST WHERE ONSHORE FLOW SHOULD HELP PREVENT CRITICAL RELATIVE
HUMIDITY LEVELS. SEVERAL HOURS OF CRITICALLY LOW RELATIVE HUMIDITY
APPEAR LIKELY FOR THURSDAY LATE MORNING/AFTERNOON AS WELL.
HOWEVER...LIGHTER WINDS AND CURRENT ERC VALUES BELOW 37 DO NOT
MATCH RED FLAG CRITERIA FOR ANY ZONES. THIS POTENTIAL FOR RED FLAG
CONDITIONS CAN BE RE-EVALUATED THIS AFTERNOON WITH THE ISSUANCE OF
THE NEW ERC VALUES. IF ANY ZONES RISE TO 37 OR HIGHER...WARNINGS
WILL LIKELY BECOME REQUIRED.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 64 43 67 47 / 10 0 0 0
FMY 72 44 71 48 / 30 0 0 0
GIF 68 40 72 44 / 10 0 0 0
SRQ 65 44 67 46 / 20 0 0 0
BKV 64 36 68 38 / 10 0 0 0
SPG 63 49 67 53 / 10 0 0 0
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...LAKE WIND ADVISORY FROM 10 AM THIS MORNING TO 7 PM EST
THIS EVENING FOR CHARLOTTE-CITRUS-DESOTO-HARDEE-
HERNANDO-HIGHLANDS-HILLSBOROUGH-LEE-LEVY-MANATEE-
PASCO-PINELLAS-POLK-SARASOTA-SUMTER.
RED FLAG WARNING FROM NOON TODAY TO 7 PM EST THIS EVENING
FOR CHARLOTTE-CITRUS-DESOTO-HARDEE-HERNANDO-HIGHLANDS-
HILLSBOROUGH-LEE-LEVY-MANATEE-PASCO-POLK-SARASOTA-
SUMTER.
BEACH HAZARDS STATEMENT THROUGH THURSDAY MORNING FOR
CHARLOTTE-HILLSBOROUGH-LEE-MANATEE-PINELLAS-SARASOTA.
GULF WATERS...SMALL CRAFT ADVISORY UNTIL 4 AM EST THURSDAY FOR TARPON
SPRINGS TO SUWANNEE RIVER OUT 20 NM-TARPON SPRINGS TO
SUWANNEE RIVER OUT 20 TO 60 NM.
SMALL CRAFT ADVISORY UNTIL 4 AM EST THURSDAY FOR BONITA
BEACH TO ENGLEWOOD OUT 20 NM-BONITA BEACH TO
ENGLEWOOD OUT 20 TO 60 NM-ENGLEWOOD TO TARPON SPRINGS
OUT 20 NM-ENGLEWOOD TO TARPON SPRINGS OUT 20 TO 60 NM-
TAMPA BAY WATERS.
&&
$$
SYNOPSIS/SHORT TERM/MARINE/FIRE WX...MROCZKA
LONG TERM/AVIATION...RUDE
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
249 PM EST WED MAR 6 2013
.UPDATE...
THE LONG TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 350 AM EST WED MAR 6 2013
STRONG LOW PRESSURE OVER SOUTHEAST OHIO WILL MOVE ON TO THE EAST
COAST AS UPPER DISTURBANCE MOVES SOUTHEAST ACROSS THE GREAT LAKES.
OVER THE NEXT FEW DAYS MODELS MOVE AN AREA OF HIGH PRESSURE EAST
INTO OUR REGION AND AN UPPER RIDGE OF HIGH PRESSURE OVER THE ROCKIES
WILL MOVE OUR WAY BY SATURDAY.
IN THE EXTENDED..AN AREA OF LOW PRESSURE WILL MOVE OUR WAY LATE
SUNDAY AND MONDAY. TEMPERATURES WILL BE QUITE MILD THIS
WEEKEND...BUT WILL COOL OFF SOME MONDAY AND TUESDAY AFTER A COLD
FRONT MOVES THROUGH.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 1006 AM EST WED MAR 6 2013
RADAR LOOP SHOWED SNOW SHOWERS HAD MOVED OUT OF THE AREA EARLIER
THIS MORNING SO WINTER WEATHER ADVISORY WAS ALLOWED TO EXPIRE AT 9
AM. SATELLITE PICTURE SHOWS CLOUDY SKIES ACROSS ALL OF CENTRAL
INDIANA AND THIS TREND SHOULD CONTINUE THROUGH THE DAY...WITH
PERHAPS MOSTLY CLOUDY BY LATE THIS EVENING. WING GUSTS OF 20 TO 30
MPH CONTINUE ACROSS THE AREA BUT SHOULD LESSEN GRADUALLY
THROUGHOUT THE DAY. FORECAST SOUNDINGS IN BOTH THE NAM AND THE RAP FOR
THIS AFTERNOON SHOW SOME SHALLOW INSTABILITY AND RECENTLY THIS HAS
BEEN A PRETTY GOOD INDICATOR OF LIGHT SNOW SHOWER DEVELOPMENT.
WITH LITTLE IN THE WAY OF FORCING ON THE BACK SIDE OF THIS LOW HAVE
OPTED AGAINST ADDING ANYTHING MEASURABLE BUT HAVE ADDED A CHANCE
FOR FLURRIES FOR THE AFTERNOON. GOING HIGH TEMPERATURES IN THE 30S
LOOK GOOD WITH THE CLOUD COVER AND NORTHWEST FLOW.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...
ISSUED AT 350 AM EST WED MAR 6 2013
FORECAST FOCUS WILL BE ON SKY COVER AND TEMPERATURES AS MUCH QUIETER
WEATHER WILL BE THE RULE. HIGH PRESSURE RIDGE DRIFTS ACROSS THE
PLAINS WILL BUILD EAST ACROSS OUR REGION FRIDAY. WITH
SUBSIDENCE...CLOUDS WILL GRADUALLY DECREASE LATER TONIGHT AND
THURSDAY. MODELS MOVE AN UPPER DISTURBANCE ACROSS SOUTHEAST ACROSS
THE EASTERN GREAT LAKES AND EASTERN OHIO LATER TONIGHT AND THURSDAY.
WILL KEEP MORE CLOUDS ACROSS OUR NORTH AND EAST THROUGH THURSDAY.
OTHERWISE...MOST AREAS WILL BECOME MOSTLY CLEAR THURSDAY NIGHT AND
REMAIN THAT WAY UNTIL SATURDAY MORNING.
WILL LEAN TOWARDS THE COOLER END OF MOS TEMPERATURES THROUGH
THURSDAY NIGHT AS THERE WILL BE SOME SNOW COVER ESPECIALLY EAST.
WITH CLEAR SKIES AND LIGHT WINDS WILL UNDERCUT MOS TEMPERATURES 4 TO
6 DEGREES THURSDAY NIGHT. BY FRIDAY THE SNOW COVER SHOULD BE MOSTLY
GONE AND WILL WITH THE POSSIBLE EXCEPTION OUR FAR EAST. WILL GO
CLOSE TO A MOS BLEND ON TEMPERATURES.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
ISSUED AT 249 PM EST WED MAR 6 2013
ACTIVE PATTERN RETURNS THROUGH THE PERIOD. AN UPPER LEVEL TROUGH
WILL EJECT OUT OF THE ROCKIES SATURDAY NIGHT AND INDUCE A SURFACE
LOW THAT WILL TRACK ACROSS THE CENTRAL PLAINS ON SUNDAY. EXTENDED
MODEL GUIDANCE IN DECENT AGREEMENT ON KEEPING THE UPPER LEVEL WAVE
FAIRLY PROGRESSIVE AS RIDGING ALOFT AHEAD OF THE SYSTEM BREAKS
DOWN BY EARLY MONDAY. NICE SURGE OF WARM GULF AIR AHEAD OF THE
SYSTEM WILL TRANSPORT PLENTY OF MOISTURE INTO THE OHIO VALLEY WITH
PRECIP WATER VALUES CLIMBING TO AN INCH OR BETTER BY SUNDAY NIGHT
AND MONDAY. ANY LINGERING PILES OF SNOW THAT STILL REMAIN BY THE
WEEKEND WILL LIKELY BE WIPED OUT AS EXPECT WIDESPREAD RAINFALL TO
ACCOMPANY THE LOW PRESSURE AND FRONTAL BOUNDARY. WILL CARRY LIKELY
POPS SUNDAY NIGHT AND MONDAY AS THE LOW PASSES THROUGH THE OHIO
VALLEY.
HIGHS MAINLY IN THE 50S SUNDAY AND UPPER 40S/LOWER 50S MONDAY WILL
FALL BACK INTO THE 40S FOR TUESDAY AND WEDNESDAY AS COLDER AIR
RETURNS IN THE WAKE OF THE FRONTAL PASSAGE. COLDEST TEMPERATURES
THROUGHOUT THE EXTENDED LIKELY TO BE WEDNESDAY AS AN UPPER LEVEL
TROUGH CARVES OUT ACROSS THE GREAT LAKES. MAY SEE LIGHT SNOW MIX
IN WITH RAIN AS PRECIP DIMINISHES MONDAY NIGHT INTO TUESDAY...WITH
DRIER WEATHER RESUMING FOR MIDWEEK.
&&
.AVIATION /DISCUSSION FOR 061800Z TAF ISSUANCE/...
ISSUED AT 1222 PM EST WED MAR 6 2013
MVFR CEILINGS TO PERSIST THROUGHOUT THE FORECAST PERIOD.
CENTRAL INDIANA REMAINS IN A COLD CYCLONIC FLOW IN THE WAKE OF THE
STORM THAT IMPACTED THE REGION LAST NIGHT AND EARLY THIS MORNING.
EXTENSIVE STRATUS DECK ENCOMPASSING THE GREAT LAKES AND OHIO
VALLEY...WITH CEILINGS GENERALLY BETWEEN 1000-1500FT. EXPECT THICK
STRATUS DECK TO REMAIN FOR THE REST OF THE DAY AND OVERNIGHT...
POSSIBLY LIFTING TOWARDS 2000FT THROUGH THIS EVENING BEFORE
FALLING BACK TONIGHT WITH THE INVERSION HOLDING. VERY WEAK SHALLOW
INSTABILITY PRESENT THROUGH THE AFTERNOON COULD GENERATE A FEW
FLURRIES WITH NO IMPACT TO TERMINALS. NORTHWEST WINDS AT 10-15KTS
THIS AFTERNOON WILL DIMINISH TO AROUND 5KTS TONIGHT.
INCREASINGLY DRIER AIR BUILDING INTO THE REGION THURSDAY WITH HIGH
PRESSURE...BUT MODEL SOUNDINGS INDICATING LOWER CLOUDS WILL LIKELY
BE SLOW TO BUDGE. WILL RAISE CEILINGS TO 2KFT THURSDAY MORNING
WITH MORE SUBSTANTIAL CLEARING LIKELY TO HOLD OFF UNTIL LATER ON
THURSDAY. LIGHT NORTHERLY FLOW IS EXPECTED THURSDAY.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...JH
NEAR TERM...CP
SHORT TERM...JH
LONG TERM....RYAN
AVIATION...RYAN
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1222 PM EST WED MAR 6 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 350 AM EST WED MAR 6 2013
STRONG LOW PRESSURE OVER SOUTHEAST OHIO WILL MOVE ON TO THE EAST
COAST AS UPPER DISTURBANCE MOVES SOUTHEAST ACROSS THE GREAT LAKES.
OVER THE NEXT FEW DAYS MODELS MOVE AN AREA OF HIGH PRESSURE EAST
INTO OUR REGION AND AN UPPER RIDGE OF HIGH PRESSURE OVER THE ROCKIES
WILL MOVE OUR WAY BY SATURDAY.
IN THE EXTENDED..AN AREA OF LOW PRESSURE WILL MOVE OUR WAY LATE
SUNDAY AND MONDAY. TEMPERATURES WILL BE QUITE MILD THIS
WEEKEND...BUT WILL COOL OFF SOME MONDAY AND TUESDAY AFTER A COLD
FRONT MOVES THROUGH.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 1006 AM EST WED MAR 6 2013
RADAR LOOP SHOWED SNOW SHOWERS HAD MOVED OUT OF THE AREA EARLIER
THIS MORNING SO WINTER WEATHER ADVISORY WAS ALLOWED TO EXPIRE AT 9
AM. SATELLITE PICTURE SHOWS CLOUDY SKIES ACROSS ALL OF CENTRAL
INDIANA AND THIS TREND SHOULD CONTINUE THROUGH THE DAY...WITH
PERHAPS MOSTLY CLOUDY BY LATE THIS EVENING. WING GUSTS OF 20 TO 30
MPH CONTINUE ACROSS THE AREA BUT SHOULD LESSEN GRADUALLY
THROUGHOUT THE DAY. FORECAST SOUNDINGS IN BOTH THE NAM AND THE RAP FOR
THIS AFTERNOON SHOW SOME SHALLOW INSTABILITY AND RECENTLY THIS HAS
BEEN A PRETTY GOOD INDICATOR OF LIGHT SNOW SHOWER DEVELOPMENT.
WITH LITTLE IN THE WAY OF FORCING ON THE BACK SIDE OF THIS LOW HAVE
OPTED AGAINST ADDING ANYTHING MEASURABLE BUT HAVE ADDED A CHANCE
FOR FLURRIES FOR THE AFTERNOON. GOING HIGH TEMPERATURES IN THE 30S
LOOK GOOD WITH THE CLOUD COVER AND NORTHWEST FLOW.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...
ISSUED AT 350 AM EST WED MAR 6 2013
FORECAST FOCUS WILL BE ON SKY COVER AND TEMPERATURES AS MUCH QUIETER
WEATHER WILL BE THE RULE. HIGH PRESSURE RIDGE DRIFTS ACROSS THE
PLAINS WILL BUILD EAST ACROSS OUR REGION FRIDAY. WITH
SUBSIDENCE...CLOUDS WILL GRADUALLY DECREASE LATER TONIGHT AND
THURSDAY. MODELS MOVE AN UPPER DISTURBANCE ACROSS SOUTHEAST ACROSS
THE EASTERN GREAT LAKES AND EASTERN OHIO LATER TONIGHT AND THURSDAY.
WILL KEEP MORE CLOUDS ACROSS OUR NORTH AND EAST THROUGH THURSDAY.
OTHERWISE...MOST AREAS WILL BECOME MOSTLY CLEAR THURSDAY NIGHT AND
REMAIN THAT WAY UNTIL SATURDAY MORNING.
WILL LEAN TOWARDS THE COOLER END OF MOS TEMPERATURES THROUGH
THURSDAY NIGHT AS THERE WILL BE SOME SNOW COVER ESPECIALLY EAST.
WITH CLEAR SKIES AND LIGHT WINDS WILL UNDERCUT MOS TEMPERATURES 4 TO
6 DEGREES THURSDAY NIGHT. BY FRIDAY THE SNOW COVER SHOULD BE MOSTLY
GONE AND WILL WITH THE POSSIBLE EXCEPTION OUR FAR EAST. WILL GO
CLOSE TO A MOS BLEND ON TEMPERATURES.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
ISSUED AT 336 PM EST TUE MAR 5 2013
AN UPPER RIDGE WILL BUILD OVER THE REGION LATE IN THE WORK WEEK AND
MOVES EAST CROSS THE REGION THROUGH THE WEEKEND. DRY WEATHER AND
WARMER TEMPERATURES WILL ENSUE ACROSS THE AREA. BY SUNDAY A BROAD
UPPER TROUGH WILL APPROACH THE REGION. A DISTURBANCE OUT OF AHEAD OF
THIS SYSTEM WILL MOVE ACROSS THE AREA SUNDAY...WITH THE STRONG UPPER
LOW TO CROSS THE REGION MONDAY AND TUESDAY. SLIGHT CHANCE FOR RAIN
WILL BE IN THE FORECAST FOR SUNDAY WITH HIGHER CHANCES FROM MONDAY
INTO TUESDAY AS THE CENTER OF THE UPPER LOW MOVES ACROSS THE GREAT
LAKES. ALL BLEND TEMPERATURES SEEM REASONABLE GIVEN MODEL CONSENSUS
AND DID NOT MAKE ANY SIGNIFICANT CHANGES TO THEIR NUMBERS.
&&
.AVIATION /DISCUSSION FOR 061800Z TAF ISSUANCE/...
ISSUED AT 1222 PM EST WED MAR 6 2013
MVFR CEILINGS TO PERSIST THROUGHOUT THE FORECAST PERIOD.
CENTRAL INDIANA REMAINS IN A COLD CYCLONIC FLOW IN THE WAKE OF THE
STORM THAT IMPACTED THE REGION LAST NIGHT AND EARLY THIS MORNING.
EXTENSIVE STRATUS DECK ENCOMPASSING THE GREAT LAKES AND OHIO
VALLEY...WITH CEILINGS GENERALLY BETWEEN 1000-1500FT. EXPECT THICK
STRATUS DECK TO REMAIN FOR THE REST OF THE DAY AND OVERNIGHT...
POSSIBLY LIFTING TOWARDS 2000FT THROUGH THIS EVENING BEFORE
FALLING BACK TONIGHT WITH THE INVERSION HOLDING. VERY WEAK SHALLOW
INSTABILITY PRESENT THROUGH THE AFTERNOON COULD GENERATE A FEW
FLURRIES WITH NO IMPACT TO TERMINALS. NORTHWEST WINDS AT 10-15KTS
THIS AFTERNOON WILL DIMINISH TO AROUND 5KTS TONIGHT.
INCREASINGLY DRIER AIR BUILDING INTO THE REGION THURSDAY WITH HIGH
PRESSURE...BUT MODEL SOUNDINGS INDICATING LOWER CLOUDS WILL LIKELY
BE SLOW TO BUDGE. WILL RAISE CEILINGS TO 2KFT THURSDAY MORNING
WITH MORE SUBSTANTIAL CLEARING LIKELY TO HOLD OFF UNTIL LATER ON
THURSDAY. LIGHT NORTHERLY FLOW IS EXPECTED THURSDAY.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...JH
NEAR TERM...CP
SHORT TERM...JH
LONG TERM....NIELD
AVIATION...RYAN
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1006 AM EST WED MAR 6 2013
.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 350 AM EST WED MAR 6 2013
STRONG LOW PRESSURE OVER SOUTHEAST OHIO WILL MOVE ON TO THE EAST
COAST AS UPPER DISTURBANCE MOVES SOUTHEAST ACROSS THE GREAT LAKES.
OVER THE NEXT FEW DAYS MODELS MOVE AN AREA OF HIGH PRESSURE EAST
INTO OUR REGION AND AN UPPER RIDGE OF HIGH PRESSURE OVER THE ROCKIES
WILL MOVE OUR WAY BY SATURDAY.
IN THE EXTENDED..AN AREA OF LOW PRESSURE WILL MOVE OUR WAY LATE
SUNDAY AND MONDAY. TEMPERATURES WILL BE QUITE MILD THIS
WEEKEND...BUT WILL COOL OFF SOME MONDAY AND TUESDAY AFTER A COLD
FRONT MOVES THROUGH.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 1006 AM EST WED MAR 6 2013
RADAR LOOP SHOWED SNOW SHOWERS HAD MOVED OUT OF THE AREA EARLIER
THIS MORNING SO WINTER WEATHER ADVISORY WAS ALLOWED TO EXPIRE AT 9
AM. SATELLITE PICTURE SHOWS CLOUDY SKIES ACROSS ALL OF CENTRAL
INDIANA AND THIS TREND SHOULD CONTINUE THROUGH THE DAY...WITH
PERHAPS MOSTLY CLOUDY BY LATE THIS EVENING. WING GUSTS OF 20 TO 30
MPH CONTINUE ACROSS THE AREA BUT SHOULD LESSEN GRADUALLY
THROUGHOUT THE DAY. FORECAST SOUNDINGS IN BOTH THE NAM AND THE RAP FOR
THIS AFTERNOON SHOW SOME SHALLOW INSTABILITY AND RECENTLY THIS HAS
BEEN A PRETTY GOOD INDICATOR OF LIGHT SNOW SHOWER DEVELOPMENT.
WITH LITTLE IN THE WAY OF FORCING ON THE BACK SIDE OF THIS LOW HAVE
OPTED AGAINST ADDING ANYTHING MEASURABLE BUT HAVE ADDED A CHANCE
FOR FLURRIES FOR THE AFTERNOON. GOING HIGH TEMPERATURES IN THE 30S
LOOK GOOD WITH THE CLOUD COVER AND NORTHWEST FLOW.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...
ISSUED AT 350 AM EST WED MAR 6 2013
FORECAST FOCUS WILL BE ON SKY COVER AND TEMPERATURES AS MUCH QUIETER
WEATHER WILL BE THE RULE. HIGH PRESSURE RIDGE DRIFTS ACROSS THE
PLAINS WILL BUILD EAST ACROSS OUR REGION FRIDAY. WITH
SUBSIDENCE...CLOUDS WILL GRADUALLY DECREASE LATER TONIGHT AND
THURSDAY. MODELS MOVE AN UPPER DISTURBANCE ACROSS SOUTHEAST ACROSS
THE EASTERN GREAT LAKES AND EASTERN OHIO LATER TONIGHT AND THURSDAY.
WILL KEEP MORE CLOUDS ACROSS OUR NORTH AND EAST THROUGH THURSDAY.
OTHERWISE...MOST AREAS WILL BECOME MOSTLY CLEAR THURSDAY NIGHT AND
REMAIN THAT WAY UNTIL SATURDAY MORNING.
WILL LEAN TOWARDS THE COOLER END OF MOS TEMPERATURES THROUGH
THURSDAY NIGHT AS THERE WILL BE SOME SNOW COVER ESPECIALLY EAST.
WITH CLEAR SKIES AND LIGHT WINDS WILL UNDERCUT MOS TEMPERATURES 4 TO
6 DEGREES THURSDAY NIGHT. BY FRIDAY THE SNOW COVER SHOULD BE MOSTLY
GONE AND WILL WITH THE POSSIBLE EXCEPTION OUR FAR EAST. WILL GO
CLOSE TO A MOS BLEND ON TEMPERATURES.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
ISSUED AT 336 PM EST TUE MAR 5 2013
AN UPPER RIDGE WILL BUILD OVER THE REGION LATE IN THE WORK WEEK AND
MOVES EAST CROSS THE REGION THROUGH THE WEEKEND. DRY WEATHER AND
WARMER TEMPERATURES WILL ENSUE ACROSS THE AREA. BY SUNDAY A BROAD
UPPER TROUGH WILL APPROACH THE REGION. A DISTURBANCE OUT OF AHEAD OF
THIS SYSTEM WILL MOVE ACROSS THE AREA SUNDAY...WITH THE STRONG UPPER
LOW TO CROSS THE REGION MONDAY AND TUESDAY. SLIGHT CHANCE FOR RAIN
WILL BE IN THE FORECAST FOR SUNDAY WITH HIGHER CHANCES FROM MONDAY
INTO TUESDAY AS THE CENTER OF THE UPPER LOW MOVES ACROSS THE GREAT
LAKES. ALL BLEND TEMPERATURES SEEM REASONABLE GIVEN MODEL CONSENSUS
AND DID NOT MAKE ANY SIGNIFICANT CHANGES TO THEIR NUMBERS.
&&
.AVIATION /DISCUSSION FOR THE 061500Z TAF UPDATE/...
ISSUED AT 947 AM EST WED MAR 6 2013
THICK MVFR STRATUS REMAINS ACROSS THE REGION THIS MORNING. MADE SOME
MINOR ADJUSTMENTS TO CEILINGS BASED ON CURRENT OBS BUT IN
GENERAL...12Z FORECAST LOOKS GOOD. GUSTS LIKELY TO CONTINUE AT
KBMG...KIND AND POSSIBLY KHUF THROUGH THE REMAINDER OF THE MORNING.
CANNOT RULE OUT A FEW FLURRIES INTO THE AFTERNOON...BUT ANY IMPACT
TO TERMINALS WILL BE MINIMAL AT BEST AND WILL NOT INTRODUCE INTO
FORECASTS AT THIS TIME.
12Z DISCUSSION FOLLOWS.
MVFR CONDITIONS LIKELY THROUGH THE PERIOD IN THE WAKE OF DEPARTING
LOW PRESSURE.
SAVE FOR HUF...ALL SITES ARE NOW MVFR AND SNOW IS RAPIDLY COMING TO
AN END...ASIDE FROM A FEW FLURRIES REMAINING.
APPEARS LIKELY THAT MOISTURE WILL REMAIN TRAPPED UNDER A LOW LEVEL
INVERSION THROUGH MUCH OF THE PERIOD...AND UPSTREAM OBSERVATIONS AND
SATELLITE BEAR THIS OUT...SHOWING EXPANSIVE LOW CLOUD TO OUR WEST
AND NORTHWEST.
WINDS WILL GENERALLY REMAIN NORTHWESTERLY...WITH SOME GUSTS LIKELY
EARLY IN THE PERIOD BEFORE THE SURFACE PRESSURE GRADIENT RELAXES.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...JH
NEAR TERM...CP
SHORT TERM...JH
LONG TERM....NIELD
AVIATION...NIELD/RYAN
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
340 PM CST WED MAR 6 2013
.SYNOPSIS...
ISSUED AT 332 PM CST WED MAR 6 2013
12Z UA ANALYSIS HAS A STRONG EXTRATROPICAL CYCLONE OVER THE MID
ATLANTIC STATES WITH A RIDGE OVER THE PLAINS. SATELLITE TRENDS
THROUGH MID AFTERNOON SHOW GRADUAL CLEARING AS THE STRONGER MARCH
ALLOWS BREAKS TO DEVELOP IN THE MOISTURE LAYER TRAPPED UNDER THE
INVERSION.
18Z SFC ANALYSIS HAS A RIDGE THROUGH THE PLAINS WITH AN INVERTED
TROF RUNNING FROM THE OHIO VALLEY INTO UPPER MICHIGAN. DEW POINTS
WERE IN THE TEENS AND 20S ACROSS THE MIDWEST.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 332 PM CST WED MAR 6 2013
NOT ONE MODEL IS HANDLING THE THIN MOISTURE LAYER TRAPPED UNDER
THE INVERSION. THE RAP 0.5 KM RH/CONDENSATION PRESSURE/WIND HAS A
LOOSE CORRELATION ON WHAT IS CURRENTLY HAPPENING.
TAKING INPUTS FROM THE RAP TRENDS AND COMBINING THEM WITH SATELLITE
TRENDS INDICATES CLEARING WILL OCCUR ACROSS THE WESTERN THIRD OF THE
CWFA LATE THIS AFTERNOON WITH IT PROGRESSING EAST TO THE MISSISSIPPI
BY SUNSET. AFTER SUNSET THE QUESTION THEN BECOMES WILL THE CLEARING
TREND CONTINUE OR STOP. THE RAP SUGGESTS THE CLEARING WOULD STOP
WITH CLOUDS REMAINING TRAPPED UNDER THE INVERSION. OTHER DATA
SUGGEST THE CLEARING TREND WOULD CONTINUE BUT SLOW DOWN.
SO...HAVE OPTED TO GO WITH THE IDEA OF SLOWING DOWN THE CLEARING
TREND THIS EVENING WITH THE FAR EAST CLEARING AFTER MIDNIGHT.
MOISTURE IN THE LOW LEVELS IS NOT REALLY BEING SCOURED OUT SO THOSE
AREAS THAT CLEAR BY SUNSET WILL HAVE A FOG THREAT AS THE HIGH
SETTLES ACROSS THE AREA.
GOING ON THE ASSUMPTION THAT FOG WILL DEVELOP IN THE CLEAR SKIES AND
LIGHT WINDS OVER THE SNOW PACK...AREAS ROUGHLY ALONG AND WEST OF THE
MISSISSIPPI WOULD BE MOST AT RISK STARTING TOWARD MIDNIGHT AND
CONTINUING INTO THURSDAY MORNING. THE EASTERN 40 PERCENT OF THE CWFA
MAY SEE SOME PATCHY FOG DEVELOP AROUND SUNRISE.
VERY LITTLE FOG DEVELOPED UNDER THE SFC RIDGE LAST NIGHT DUE TO
CLOUD COVER. SO IT IS NOT KNOWN IF HEADLINES WOULD BE NEEDED FOR ANY
FOG THAT DEVELOPS TONIGHT. TRENDS WILL NEED TO BE MONITORED DURING
THE EVENING FOR THIS POSSIBLE THREAT.
IF FOG DEVELOPS TONIGHT AND BECOMES SUFFICIENTLY THICK...THEN RIME
DEPOSITS COULD DEVELOP ON SOME ROADS AND POSSIBLY RESULT IN SLICK
SPOTS DEVELOPING.
THURSDAY LOOKS TO BE QUIET AND DRY WITH SUNSHINE AS THE HIGH SLOWLY
MOVES TOWARD MICHIGAN AND INDIANA.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 332 PM CST WED MAR 6 2013
MAIN FOCUS WITH STORM SYSTEM OVER THE WEEKEND INTO VERY EARLY NEXT
WEEK AND PCPN CHCS/TYPE/AMOUNTS.
LARGE CUTOFF LOW CHURNING JUST OFF THE PACIFIC NORTHWEST COAST
EARLY THIS AFTERNOON IS SHOWN BY MODELS TO DIG INTO THE
SOUTHWESTERN CONUS BY LATE WEEK BEFORE EJECTING OUT FROM THE
ROCKIES THROUGH THE MID-MISSISSIPPI VALLEY OVER THE WEEKEND INTO
EARLY NEXT WEEK. MODELS GENERALLY SHOW THE LOW OPENING UP AND
EJECTING OUT AS POSITIVE TILTED TROUGH AS SUGGESTION OF SOME PHASING
WITH CANADIAN PLAINS SHORTWAVE ENERGY. THE UNCERTAINTIES MOSTLY
PERTAIN TO THE TRACK...AND ALSO STRENGTH/TIMING OF SYSTEM
WEAKENING OR OPENING UP BOTH OF WHICH LIKELY IMPACTED BY THE AMOUNT
OF INTERACTION WITH CANADIAN ENERGY. THE UNCERTAINTIES WITH TRACK
AND STRENGTH OF SYSTEM TO HAVE IMPACT ON TEMPS AND PRECIPITATION TYPE
AND AMOUNTS...AND WHETHER OR NOT WILL SEE A DEFORMATION ZONE. THIS
WILL PROBABLY TO TAKE AT LEAST ANOTHER 24+ HRS TO RESOLVE AS THE
CANADIAN ENERGY MOSTLY IN QUESTION IS STILL WELL OUT IN THE PACIFIC
JUST SOUTH OF THE ALEUTIAN ISLANDS.
THU NGT-FRIDAY NGT... MAINLY DRY AS HIGH PRESSURE IN CONTROL FOR MUCH
OF THE PERIOD. FAVORED NEAR THE COLD SIDE OF GUIDANCE OR JUST BELOW
ON TEMPS AS PAST EXPERIENCE WITH DRY LOW LEVEL E/SE FLOW ON BACKSIDE
OF DEPARTING HIGH NOT CONDUCIVE FOR A LOT OF WARMING... ESPECIALLY WITH
SNOW COVER. LOW LEVEL JET AND ATTENDANT STRONG MOISTURE TRANSPORT TO
FUEL DEVELOPMENT OF PCPN TO OUR WEST BY FRIDAY EVENING AND MAY SEE
SOME STRATIFYING LIGHT PCPN MOVE INTO WESTERN SECTIONS LATE FRIDAY NGT
WITH VEERING/WEAKENING LOW LEVEL JET WELL NORTH OF DEVELOPING SFC WARM
FRONT. COLD DRY FETCH FROM DEPARTING HIGH AND EVAPORATIONAL COOLING
SUPPORT RISK OF SOME FREEZING RAIN WITH INITIAL ONSET OF PCPN
BEFORE SATURATION AND CONTINUED WARM... MOIST ADVECTION ABATES RISK
SATURDAY AM.
SAT-SUN... RAIN EXPECTED TO EVENTUALLY OVERSPREAD CWA SAT-SAT NGT AND
LINGER THROUGH SUNDAY WITH STRONG MOISTURE TRANSPORT AND INCREASINGLY
DIFFLUENT FLOW ALOFT. SFC DEWPTS WELL INTO THE 40S AND 850 MB DEWPTS
OF 5-7C COMBINED WITH MAGNITUDE OF FORCING SUPPORTIVE OF WIDESPREAD
MODERATE TO HEAVY RAIN AMOUNTS 0.25 TO 1 INCH... WITH LOCALLY
HIGHER AMOUNTS 1-2 INCHES WITH SOME CONVECTION. THIS RAISES CONCERNS
ON FLOODING WITH POTENTIAL FOR RAPID SNOWMELT OCCURRING ALONGSIDE THE
MODERATE TO HEAVY RAINS GIVEN AREA STREAMS AND RIVERS NEAR TO ABOVE
NORMAL IN MANY LOCATIONS... WHILE FROST DEPTH DOWN TO 8 INCHES ALTHOUGH
SOME THAW IN TOP PORTIONS BUT SATURATED... OVERALL SUPPORTIVE OF RUN-OFF
INCREASING RISK FOR SOME LOW END FLOODING. CONTINUED TO UNCERCUT
GUIDANCE ON TEMPS SAT AND EXPECT READINGS STEADY TO SLOWLY RISING SAT
NGT THROUGH SUNDAY IF TRACK REMAINS UNCHANGED NEAR TO OVER THE
CWA. WITH DEWPTS WELL IN THE 40S TO POSSIBLY EVEN LOWER 50S SAT NGT
INTO SUNDAY WOULD EXPECT SOME GOOD ADVECTION FOG OVER THE COLDER SNOW
COVERED GROUND... WHICH COULD BE QUITE DENSE.
MON-WED... RISK OF RAIN CHANGING TO SNOW SUNDAY NGT LINGERING MON
ESPECIALLY WITH DEFORMATION ZONE IF SYSTEM SLOWER TO WEAKEN... AND WILL
HAVE TO WATCH SUN NGT INTO MON ONCE AGAIN FOR SOME ACCUMULATING
SNOW POTENTIAL. OTHERWISE... MAINLY BELOW NORMAL TEMPS MON-WED WITH
SOME SUGGESTION OF CLIPPER SYSTEM AND CHC OF LIGHT SNOW SOMETIME IN
TUE-WED TIMEFRAME... BUT THIS ALL DEPENDENT ON EVOLUTION AND TIMING OF
THE WEEKEND SYSTEM AND THUS FOR NOW HAVE NO MENTION.
BEYOND FOR 7-10+ DAYS ... STRONG INDICATION OF CONTINUED BELOW NORMAL
TEMPS WITH PERIODIC CLIPPER SYSTEMS IN GENERALLY NORTHWEST FLOW ALOFT.
05
&&
.AVIATION...
ISSUED AT 332 PM CST WED MAR 6 2013
SATELLITE TRENDS THROUGH 20Z/06 ARE NOW POINTING TO CLEARING
DVLPG AT KCID PRIOR TO SUNSET AND POTENTIALLY AT KDBQ/KMLI/BRL
AROUND OR SHORTLY AFT SUNSET. THUS CONDITIONS ARE EXPECTED TO
IMPROVE TO VFR. LIGHT WINDS OVER THE SNOW FIELD AND CLEAR SKIES
BRINGS THE THREAT OF FG DEVELOPING. IF FG DEVELOPS AFT
SUNSET...THE POTENTIAL EXISTS FOR LIFR CONDITIONS DVLPG AFT
06Z/07. 08
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...08
SHORT TERM...08
LONG TERM...05
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1130 AM CST WED MAR 6 2013
...UPDATED AVIATION DISCUSSION...
.SHORT TERM /TODAY/...
MAIN FORECAST CONCERN TODAY IS LINGERING
STRATUS DECK AND WHETHER IT WILL DISSIPATE DURING THE AFTERNOON.
SURFACE HIGH AND UPPER LEVEL RIDGE BUILD INTO THE STATE PAST 18Z
TODAY AND BRING LIGHT FLOW TO THE FORECAST AREA. INVERSION
STRENGTHENS AS DRIER AIR FILTER WITH THE UPPER RIDGE MOVING INTO THE
STATE THIS AFTERNOON. STRATUS DECK EXTENDS UP INTO CANADA AND THE
GENERALLY NORTH FLOW CONTINUES THROUGH AT LEAST MIDDAY BEFORE WINDS
BECOME LIGHT AND VARIABLE. LOW CONFIDENCE WITH STRATUS DISSIPATING
BEFORE 18Z AND EVEN AT ALL THROUGH THE AFTERNOON. VERY MINIMAL
MIXING AND IF STRATUS DECK REMAINS IN PLACE WHEN SURFACE HIGH SLIDES
OVER CENTRAL IOWA...THINKING IT WILL BECOME TRAPPED UNDERNEATH THE
INVERSION INTO THIS EVENING OR POSSIBLY TOMORROW BEFORE THE WAA
DEVELOPS ON THE BACKSIDE OF THE SURFACE HIGH. AS A
RESULT...INCREASED SKY COVER THROUGH THE AFTERNOON WITH IT SLOWLY
DISSIPATING PAST 21Z. THE 05Z HRRR KEEPS THE STRATUS GOING THROUGH
THE AFTERNOON EXCEPT THE FAR SOUTHWEST. WRT TO TEMPS TODAY...LEANED
TOWARD THE NAM FOR MAX TEMPS TODAY AS IT SEEMS TO HAVE A GOOD HANDLE
ON THE STRATUS AS WELL.
.LONG TERM /TONIGHT THROUGH TUESDAY/...
RIDGE OF HIGH PRESSURE WILL MOVE ACROSS IOWA TONIGHT. STILL
UNCERTAIN HOW WIDESPREAD THE STRATUS WILL BE OVERNIGHT. THE
STRATUS WILL BE TOUGH TO GET RID OF OVERNIGHT IF IT SURVIVES TODAY
WITH VERY LITTLE SUBSIDENCE OR STEERING FLOW IN PLACE. THE
UNCERTAINTY WITH THE STRATUS LEAVES A WIDE RANGE IN POSSIBLE LOW
TEMPERATURES OVERNIGHT. TEMPERATURES WILL DROP WELL INTO THE
SINGLE DIGITS OVERNIGHT ACROSS THE NORTHEAST WITH CLEARING BUT
WOULD REMAIN IN THE MID TO UPPER TEENS IF CLOUDS PERSIST. HAVE
LEANED TOWARDS CLEARING OR PARTIAL CLEARING AND COLDER
TEMPERATURES AT THIS TIME. THE HIGH PRESSURE RIDGE SHIFTS EAST ON
THURSDAY WITH RETURN FLOW DEVELOPING IN ADDITION TO A TRANSITION
TO MID LEVEL RIDGING. THIS WILL CONTINUE INTO FRIDAY WITH EVEN
WARMER TEMPERATURES EXPECTED IN THE UPPER 30S TO UPPER 40S.
A POTENT UPPER LEVEL SYSTEM CONSISTING OF SEVERAL STRONG SHORT
WAVES ROTATING AROUND THE CORE WILL BEGIN TO MOVE OVER CALIFORNIA
ON FRIDAY. ANOTHER SHORT WAVE UNDERCUTTING THE SYSTEM WILL PUSH
OUT AHEAD AND ARRIVE OVER NEBRASKA AND IOWA BY FRIDAY NIGHT. AN
INCREASING LOW LEVEL JET AND ASSOCIATED STRONG THETA-E ADVECTION
ALONG WITH THE QG FORCING FROM THE UPPER WAVE WILL HELP SHOWERS
AND A FEW THUNDERSTORMS DEVELOP ACROSS MAINLY CENTRAL AND WESTERN
IOWA. OVERNIGHT LOW TEMPERATURES ARE EXPECTED TO BE AT OR ABOVE
FREEZING WITH LOW LEVEL MOISTURE SURGE BRINGING DEWPOINTS IN THE
3OS TO THE AREA. THE FORECAST AREA WILL BE IN THE WARM SECTOR
THROUGH THE DAY SATURDAY. THE PRIMARY UPPER LEVEL SYSTEM WILL LIFT
INTO THE MIDWEST SATURDAY NIGHT INTO SUNDAY. THE ECMWF IS A BIT
FASTER WITH THE SFC FEATURES WITH THE COLD FRONT DROPPING THROUGH
MUCH OF CENTRAL IOWA BY 12Z SUNDAY WHILE THE GFS IS A BIT SLOWER.
ANY PRECIPITATION WILL SWITCH OVER TO SNOW BEHIND THE COLD FRONT
AS PROFILES COOL. SOME SNOW ACCUMULATIONS WILL BE POSSIBLE. COLD
ADVECTION WILL BE PROMINENT MUCH OF THE DAY SUNDAY WITH HIGH
TEMPERATURES EARLY IN THE DAY. 850 MB TEMPERATURES BY 12Z MONDAY
WILL BE -8C TO -10C ACROSS MUCH OF THE AREA AND HAVE CONTINUED THE
COOLING TREND INTO MONDAY. SOME MODERATION FOR THE END OF THE
PERIOD WITH LOW CHANCES FOR PRECIPITATION.
&&
.AVIATION...06/18Z
STRATUS WILL PERSIST ACROSS THE AREA THROUGH THE PERIOD. CEILINGS
WILL VARY BETWEEN LOW MVFR AND HIGH IFR AT TIMES...AND MAY
OCCASIONALLY SCATTER TO VFR AT SITES. HOWEVER...OVERALL TREND WILL
BE FOR MVFR CEILINGS. COULD SEE SOME BR/FG DEVELOP AT EASTERN SITES
KMCW/KALO/KOTM NEAR 12Z AS INVERSION SETS UP...BUT DO NOT HAVE
ENOUGH CONFIDENCE TO INCLUDE MENTION ATTM. NORTHWESTERLY WINDS WILL
DECREASE IN THE AFTERNOON BEFORE SHIFTING TO THE SOUTHEAST LATE IN
THE PERIOD AND WILL BE STRONG AFTER 12Z.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...PODRAZIK
LONG TERM...DONAVON
AVIATION...AWB
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1050 AM CST WED MAR 6 2013
.UPDATE...
BASED ON DATA THROUGH MID MORNING...CLEARING TODAY IS DOUBTFUL AND
QUESTIONABLE FOR TONIGHT. SATELLITE DOES SHOW HOLES IN THE CLOUD COVER
THAT IS APPROXIMATED BY THE 0.5 KM RH OF THE RAP.
THE 12Z UA DATA SHOWED A THIN LAYER OF MOISTURE TRAPPED BELOW THE
INVERSION. RAP TRENDS WITH CONDENSATION PRESSURES AND WIND AT THE
0.5 KM LEVEL DO NOT SHOW ANY SUBSTANTIAL FORCING TO HELP BREAK UP
THE CLOUDS TODAY IN SPITE OF THE STRONGER MARCH SUNSHINE. THE 0.5
KM CONDENSATION PRESSURE SUGGESTS THE HOLE ALONG THE MISS RIVER IN
WESTERN WISCONSIN MAY DRIFT SLOWLY SOUTH DURING THE DAY AND
POSSIBLY CLIP THE FAR NORTHWEST PARTS OF THE CWFA.
IF THE RAP TRENDS ARE CORRECT...THEN CLOUDS MAY NOT BREAK UP
TONIGHT OR ONLY A FEW HOLES MAY DEVELOP.
SO...WILL UPDATE THE FCST TO BE MORE PESSIMISTIC ON CLEARING TODAY
AND AT LEAST INTO THE EVENING HOURS. ..08..
&&
.AVIATION...
MOISTURE TRAPPED BELOW THE INVERSION IS RAISING QUESTIONS ON THE
MVFR CONDITIONS CLEARING LATER TODAY. RAP MODEL TRENDS SUGGESTS
THE THIN LAYER OF MOISTURE REMAINS TRAPPED AND MAY REMAIN IN PLACE
UNTIL AFTER 12Z/07. THE POTENTIAL DOES EXIST FOR BREAKS IN THE
CLOUD COVER THAT COULD ALLOW POCKETS OF VFR CONDITIONS TO DVLP BUT
MAY NOT NECESSARILY BE OVER ANY TAF SITE. ..08..
&&
.PREV DISCUSSION... /ISSUED 541 AM CST WED MAR 6 2013/
SYNOPSIS...
ISSUED AT 331 AM CST WED MAR 6 2013
CONDITIONS MUCH QUIETER TONIGHT WITH THE STRONG SURFACE LOW
ASSOCIATED WITH THE TUESDAY SNOW NOW EXITING EAST ACROSS OHIO AS
OF 3 AM THIS MORNING. NORTHWEST FLOW CONTINUES ACROSS THE AREA
WITH WIDESPREAD LOW CLOUDS. A FEW FLURRIES WERE LINGERING OVER THE
AREA AROUND MIDNIGHT...BUT THESE HAVE SINCE DISSIPATED. THERE ARE
SOME HOLES IN THE STRATUS...BUT THESE ARE RELATIVELY TRANSITORY
AND ARE NOT VISIBLY EXPANDING. IT APPEARS TO BE LOOSELY RELATED TO
SOME MID LEVEL DIVERGENCE...WHICH IS SLOWLY SHIFTING SOUTH ACROSS
THE AREA OVERNIGHT. THIS DIVERGENCE WEAKENS AND SHIFTS OUT OF THE
AREA IN THE NEXT SEVERAL HOURS. WILL BE WATCHING TRENDS TO SEE IF
THE STRATUS FILLS BACK IN. ..LE..
SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 331 AM CST WED MAR 6 2013
THE MAIN CONCERN BOTH PERIODS IS FOR HOW THE STRATUS EVOLVES OVER
THE NEXT 24 HOURS...AND ITS RELATED EFFECT ON TEMPERATURES.
TODAY...MODEL GUIDANCE IS PERSISTENT IN BREAKING UP THE LOW STRATUS
DURING LATE MORNING OR AFTERNOON HOURS. NONE OF THE MODEL GUIDANCE
IS DOING ESPECIALLY WELL WITH THESE LOW CLOUDS...MOST NOT DEPICTING
ENOUGH AREAL EXTENT AT INITIALIZATION. HOWEVER...A MORE DETAILED
LOOK AT 925MB RH GRIDS AND SOUNDINGS IMPLIES A MORE PESSIMISTIC
PICTURE. THIS LOW LEVEL RH IS TRAPPED BENEATH A LOW LEVEL
INVERSION...WHICH LIFTS DURING THE DAYTIME...BUT DOES NOT BREAK.
EXPECT THAT THE CEILINGS MAY LIFT INTO A MORE MVFR LAYER...BUT WILL
STILL BE THERE. ALSO...WE DO NOT HAVE ANY PARTICULARLY DRY AIR OR
PARTICULARLY STRONG SUBSIDENCE WORKING INTO THE AREA TODAY.
HOWEVER...THIS IS EARLY MARCH AND WE ARE WORKING WITH FAIRLY STRONG
SUNSHINE...AND CLOUDS MAY BREAK UP AS DEPICTED. SO...WHILE AM NOT
TERRIBLY OPTIMISTIC...HAVE ALLOWED CLOUD COVER TO DECREASE THIS
AFTERNOON. THE EFFECT ON TODAYS HIGH TEMPS WILL NOT BE VERY
NOTICEABLE...AND WITH THE WEAK COLD AIR ADVECTION STILL
ONGOING...EXPECT HIGHS IN THE UPPER 20S TO LOW 30S.
TONIGHT THE REAL TROUBLE WITH THE STRATUS KICKS IN...AS IT COULD
HAVE A FAIRLY MAJOR EFFECT ON THE MIN TEMPS TONIGHT. AGAIN...NEARLY
ALL GUIDANCE IMPLIES THAT WE WILL CLEAR OUT DURING THE AFTERNOON AND
BE CLEAR OR NEARLY CLEAR OVERNIGHT. MODEL GUIDANCE FOLLOWS THIS
WITH MIN TEMPS IN THE SINGLE DIGITS NORTH AND LOWER TEENS SOUTH.
ONCE AGAIN THOUGH...925MB RH VALUES IMPLY A PERSISTENT LAYER OF
RH...WITH NO STRONG FEATURES TO DRIVE THE LOW LEVEL RH OUT OF THE
AREA. SOUNDINGS ALSO SUPPORT THIS TRAPPED LOW LEVEL MOISTURE.
RIGHT NOW THE STRATUS EXTENDS BACK TO THE SURFACE RIDGE AXIS IN
NEBRASKA AND THE DAKOTAS...AND SEE NO FEATURES IN THE FORECAST OTHER
THAN SUNSHINE THAT COULD POSSIBLY MIX THE STUFF OUT DURING THE
DAYTIME OR EARLY EVENING. SO...IF WE CANNOT CLEAR THE STRATUS
DURING THE AFTERNOON...WE MAY HAVE CLOUD COVER FOR THE OVERNIGHT TO
PUT A BLANKET ON THE RADIATIONAL COOLING. WITH CLOUD COVER...EXPECT
ANOTHER NIGHT IN THE UPPER TEENS TO LOW 20S. THUS...WE HAVE A
FAIRLY LARGE BUST POTENTIAL FOR TONIGHT WITH THIS SKY COVER
DILEMMA. FOR NOW HAVE THE MOSTLY CLEAR SKIES GOING IN THE
FORECAST...WITH THE COLDER SCENARIO FOR MIN TEMPERATURES...BUT THE
NEXT SHIFT IS GOING TO HAVE TO REEVALUATE THOSE LOW CLOUDS AND
WHETHER THEY ARE GOING TO PERSIST INTO THE NIGHTTIME HOURS OR NOT.
.LE..
LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 331 AM CST WED MAR 6 2013
PRIMARY FOCUS IS ON A WARMING TREND AND RAIN CHANCES THIS WEEKEND.
THIS WILL OCCUR AS THE UPPER LOW CURRENTLY OFF THE PACIFIC NW COAST
IS PROGGED TO DIG INTO THE 4 CORNERS REGION FRIDAY NIGHT...THEN LIFT
NORTHEAST INTO THE CENTRAL U.S. BY SUNDAY AND MONDAY. AHEAD OF
THIS...A SW FLOW WILL FEED GULF MOISTURE INTO THE PLAINS BY
FRIDAY...REACHING INTO THE LOCAL FORECAST AREA SATURDAY. AT THE
SURFACE...LOW PRESSURE EMERGES TO LEE OF THE CENTRAL ROCKIES INTO
THE PLAINS FRIDAY NIGHT...THEN LIFTS NORTHEAST ALONG A SW TO NE
ORIENTED FRONTAL AXIS...THROUGH THE MID OR UPPER MS VALLEY OVER THE
WEEKEND. WHILE THE LATEST MODELS HAVE COME INTO BETTER AGREEMENT
WITH THIS OVERALL SCENARIO THAN LAST NIGHT/S RUNS...THERE REMAIN
CONSIDERABLE DIFFERENCES WITH THE TRACK AND TIMING OF THE SURFACE
LOW AND THE ASSOCIATED AMOUNT OF PHASING OF UPPER LEVEL WAVES. THE
ECMWF REMAINS SLOWER AND DOES NOT DEPICT THE GFS/S PHASING OF THE
500 MB LOW MOVING OUT OF THE SW WITH A NORTHERN STREAM TROUGH MOVING
ACROSS SOUTHERN CANADA. THIS RESULTS IN THE GFS BECOMING A MUCH MORE
PROGRESSIVE SOLUTION AND TAKING THE SURFACE LOW ON A MORE NORTHERLY
TRACK...ESPECIALLY SUNDAY AND BEYOND. FOR NOW...WILL PREFER THE
SLOWER ECMWF...BASED ON EXPERIENCE WITH SIMILAR COOL SEASON SYSTEMS
LIFTING OUT OF THE SW.
THURSDAY AND FRIDAY WILL BE PROGRESSIVELY WARMER AS THE SURFACE
RIDGE SHIFTS EAST OVER THE GREAT LAKES AND WARM ADVECTION INCREASES
ALOFT. DESPITE THE SNOW COVER...STRONG MARCH SUNSHINE SHOULD WARM
MOST AREAS ABOVE FREEZING TO REACH HIGHS IN THE 30S THURSDAY...THEN
INTO THE UPPER 30S NORTH TO NEAR 50 SOUTH ON FRIDAY WHEN SOUTHEAST
WINDS WILL BE STRONGER. THU NIGHT...LOWS RANGE FROM THE UPPER TEENS
NORTHEAST TO MID 20S SOUTHWEST...COUNTING ON AT LEAST SCATTERED MID
CLOUDS AND LIGHT WINDS TO PREVENT POSSIBLE COLDER READINGS OVER THE
LINGERING SNOW COVER.
FRIDAY NIGHT...STRONG WARM ADVECTION ON 850 MB WINDS OF 25 TO 35 KTS
WILL REACH INTO THE AREA BY MORNING. MOISTURE RETURN...HOWEVER...IS
MAINLY CONFINED TO THE SW OR WESTERN REACHES OF THE FORECAST AREA
TOWARD MORNING DEPENDING ON THE MODEL. THIS MAY TRIGGER SOME SHOWERS
AND HAVE SLIGHT CHANCES IN PLACE IN THE WEST AFTER MIDNIGHT. THERE
IS A POSSIBILITY THAT SURFACE TEMPERATURES COULD BE NEAR OR BELOW
FREEZING AT ONSET ESPECIALLY ACROSS THE NORTH FOR A THREAT OF BRIEF
FREEZING RAIN...BUT CONFIDENCE IS TOO LOW TO INCLUDE MENTION IN THE
FORECAST.
SATURDAY AND SATURDAY NIGHT...THE MAIN FEED OF GULF MOISTURE
OVERSPREADS THE AREA UNDER AN INCREASINGLY DIFFLUENT FLOW ALOFT AND
LIKELY POPS ARE IN PLACE FOR RAIN IN THE WEST DURING THE DAY AND
OVER THE ENTIRE AREA SATURDAY NIGHT FOR WHAT COULD BE WIDESPREAD
MODERATE AMOUNTS. SUNDAY...THE COLD FRONT PUSHES THROUGH THE AREA
IN SOME FASHION...LIKELY CHANGING THE RAIN TO SNOW FROM NW TO SE BY
EVENING AND CANNOT RULE OUT SOME SNOW ACCUMULATIONS AS PRECIPITATION
CONTINUES SUNDAY NIGHT. HIGHS SATURDAY AND SUNDAY SHOULD BE WELL
INTO THE 40S AND POSSIBLY LOWER 50S...FOLLOWED BY 30S AND POSSIBLY
LOWER 40S EARLY NEXT WEEK AS THE UPPER FLOW BECOMES NW AND HIGH
PRESSURE BUILDS INTO THE UPPER MS VALLEY.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DES MOINES IA
547 AM CST WED MAR 6 2013
...UPDATED AVIATION DISCUSSION...
.SHORT TERM /TODAY /...
MAIN FORECAST CONCERN TODAY IS LINGERING
STRATUS DECK AND WHETHER IT WILL DISSIPATE DURING THE AFTERNOON.
SURFACE HIGH AND UPPER LEVEL RIDGE BUILD INTO THE STATE PAST 18Z
TODAY AND BRING LIGHT FLOW TO THE FORECAST AREA. INVERSION
STRENGTHENS AS DRIER AIR FILTER WITH THE UPPER RIDGE MOVING INTO THE
STATE THIS AFTERNOON. STRATUS DECK EXTENDS UP INTO CANADA AND THE
GENERALLY NORTH FLOW CONTINUES THROUGH AT LEAST MIDDAY BEFORE WINDS
BECOME LIGHT AND VARIABLE. LOW CONFIDENCE WITH STRATUS DISSIPATING
BEFORE 18Z AND EVEN AT ALL THROUGH THE AFTERNOON. VERY MINIMAL
MIXING AND IF STRATUS DECK REMAINS IN PLACE WHEN SURFACE HIGH SLIDES
OVER CENTRAL IOWA...THINKING IT WILL BECOME TRAPPED UNDERNEATH THE
INVERSION INTO THIS EVENING OR POSSIBLY TOMORROW BEFORE THE WAA
DEVELOPS ON THE BACKSIDE OF THE SURFACE HIGH. AS A
RESULT...INCREASED SKY COVER THROUGH THE AFTERNOON WITH IT SLOWLY
DISSIPATING PAST 21Z. THE 05Z HRRR KEEPS THE STRATUS GOING THROUGH
THE AFTERNOON EXCEPT THE FAR SOUTHWEST. WRT TO TEMPS TODAY...LEANED
TOWARD THE NAM FOR MAX TEMPS TODAY AS IT SEEMS TO HAVE A GOOD HANDLE
ON THE STRATUS AS WELL.
.LONG TERM /TONIGHT THROUGH TUESDAY/...
RIDGE OF HIGH PRESSURE WILL MOVE ACROSS IOWA TONIGHT. STILL
UNCERTAIN HOW WIDESPREAD THE STRATUS WILL BE OVERNIGHT. THE
STRATUS WILL BE TOUGH TO GET RID OF OVERNIGHT IF IT SURVIVES TODAY
WITH VERY LITTLE SUBSIDENCE OR STEERING FLOW IN PLACE. THE
UNCERTAINTY WITH THE STRATUS LEAVES A WIDE RANGE IN POSSIBLE LOW
TEMPERATURES OVERNIGHT. TEMPERATURES WILL DROP WELL INTO THE
SINGLE DIGITS OVERNIGHT ACROSS THE NORTHEAST WITH CLEARING BUT
WOULD REMAIN IN THE MID TO UPPER TEENS IF CLOUDS PERSIST. HAVE
LEANED TOWARDS CLEARING OR PARTIAL CLEARING AND COLDER
TEMPERATURES AT THIS TIME. THE HIGH PRESSURE RIDGE SHIFTS EAST ON
THURSDAY WITH RETURN FLOW DEVELOPING IN ADDITION TO A TRANSITION
TO MID LEVEL RIDGING. THIS WILL CONTINUE INTO FRIDAY WITH EVEN
WARMER TEMPERATURES EXPECTED IN THE UPPER 30S TO UPPER 40S.
A POTENT UPPER LEVEL SYSTEM CONSISTING OF SEVERAL STRONG SHORT
WAVES ROTATING AROUND THE CORE WILL BEGIN TO MOVE OVER CALIFORNIA
ON FRIDAY. ANOTHER SHORT WAVE UNDERCUTTING THE SYSTEM WILL PUSH
OUT AHEAD AND ARRIVE OVER NEBRASKA AND IOWA BY FRIDAY NIGHT. AN
INCREASING LOW LEVEL JET AND ASSOCIATED STRONG THETA-E ADVECTION
ALONG WITH THE QG FORCING FROM THE UPPER WAVE WILL HELP SHOWERS
AND A FEW THUNDERSTORMS DEVELOP ACROSS MAINLY CENTRAL AND WESTERN
IOWA. OVERNIGHT LOW TEMPERATURES ARE EXPECTED TO BE AT OR ABOVE
FREEZING WITH LOW LEVEL MOISTURE SURGE BRINGING DEWPOINTS IN THE
3OS TO THE AREA. THE FORECAST AREA WILL BE IN THE WARM SECTOR
THROUGH THE DAY SATURDAY. THE PRIMARY UPPER LEVEL SYSTEM WILL LIFT
INTO THE MIDWEST SATURDAY NIGHT INTO SUNDAY. THE ECMWF IS A BIT
FASTER WITH THE SFC FEATURES WITH THE COLD FRONT DROPPING THROUGH
MUCH OF CENTRAL IOWA BY 12Z SUNDAY WHILE THE GFS IS A BIT SLOWER.
ANY PRECIPITATION WILL SWITCH OVER TO SNOW BEHIND THE COLD FRONT
AS PROFILES COOL. SOME SNOW ACCUMULATIONS WILL BE POSSIBLE. COLD
ADVECTION WILL BE PROMINENT MUCH OF THE DAY SUNDAY WITH HIGH
TEMPERATURES EARLY IN THE DAY. 850 MB TEMPERATURES BY 12Z MONDAY
WILL BE -8C TO -10C ACROSS MUCH OF THE AREA AND HAVE CONTINUED THE
COOLING TREND INTO MONDAY. SOME MODERATION FOR THE END OF THE
PERIOD WITH LOW CHANCES FOR PRECIPITATION.
&&
.AVIATION...
MVFR STRATUS WILL CONTINUE THROUGH MUCH OF THE DAY AND POSSIBLY
INTO TONIGHT. CONFIDENCE IS GROWING WITH THIS STRATUS PERSISTING
INTO THURSDAY MORNING AS HIRES MODELS KEEP IT THROUGH LATE THIS
AFTERNOON AND WITH THE HIGH BUILDING INTO THE STATE...EXPECTING
INVERSION TO HOLD IT IN PLACE THROUGH TONIGHT. MOS GUIDANCE
REDEVELOPS MVFR STRATUS BY 03Z THURSDAY. HAVE BRIEF BREAK IN THE
MVFR CIGS THIS AFTERNOON...BUT BRING IT BACK IN LATE TONIGHT INTO
THE OVERNIGHT HOURS.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...PODRAZIK
LONG TERM...DONAVON
AVIATION...PODRAZIK
AREA FORECAST DISCUSSION
NWS DES MOINES IA
356 AM CST WED MAR 6 2013
.SHORT TERM /TODAY /...
MAIN FORECAST CONCERN TODAY IS LINGERING
STRATUS DECK AND WHETHER IT WILL DISSIPATE DURING THE AFTERNOON.
SURFACE HIGH AND UPPER LEVEL RIDGE BUILD INTO THE STATE PAST 18Z
TODAY AND BRING LIGHT FLOW TO THE FORECAST AREA. INVERSION
STRENGTHENS AS DRIER AIR FILTER WITH THE UPPER RIDGE MOVING INTO THE
STATE THIS AFTERNOON. STRATUS DECK EXTENDS UP INTO CANADA AND THE
GENERALLY NORTH FLOW CONTINUES THROUGH AT LEAST MIDDAY BEFORE WINDS
BECOME LIGHT AND VARIABLE. LOW CONFIDENCE WITH STRATUS DISSIPATING
BEFORE 18Z AND EVEN AT ALL THROUGH THE AFTERNOON. VERY MINIMAL
MIXING AND IF STRATUS DECK REMAINS IN PLACE WHEN SURFACE HIGH SLIDES
OVER CENTRAL IOWA...THINKING IT WILL BECOME TRAPPED UNDERNEATH THE
INVERSION INTO THIS EVENING OR POSSIBLY TOMORROW BEFORE THE WAA
DEVELOPS ON THE BACKSIDE OF THE SURFACE HIGH. AS A
RESULT...INCREASED SKY COVER THROUGH THE AFTERNOON WITH IT SLOWLY
DISSIPATING PAST 21Z. THE 05Z HRRR KEEPS THE STRATUS GOING THROUGH
THE AFTERNOON EXCEPT THE FAR SOUTHWEST. WRT TO TEMPS TODAY...LEANED
TOWARD THE NAM FOR MAX TEMPS TODAY AS IT SEEMS TO HAVE A GOOD HANDLE
ON THE STRATUS AS WELL.
.LONG TERM /TONIGHT THROUGH TUESDAY/...
RIDGE OF HIGH PRESSURE WILL MOVE ACROSS IOWA TONIGHT. STILL
UNCERTAIN HOW WIDESPREAD THE STRATUS WILL BE OVERNIGHT. THE
STRATUS WILL BE TOUGH TO GET RID OF OVERNIGHT IF IT SURVIVES TODAY
WITH VERY LITTLE SUBSIDENCE OR STEERING FLOW IN PLACE. THE
UNCERTAINTY WITH THE STRATUS LEAVES A WIDE RANGE IN POSSIBLE LOW
TEMPERATURES OVERNIGHT. TEMPERATURES WILL DROP WELL INTO THE
SINGLE DIGITS OVERNIGHT ACROSS THE NORTHEAST WITH CLEARING BUT
WOULD REMAIN IN THE MID TO UPPER TEENS IF CLOUDS PERSIST. HAVE
LEANED TOWARDS CLEARING OR PARTIAL CLEARING AND COLDER
TEMPERATURES AT THIS TIME. THE HIGH PRESSURE RIDGE SHIFTS EAST ON
THURSDAY WITH RETURN FLOW DEVELOPING IN ADDITION TO A TRANSITION
TO MID LEVEL RIDGING. THIS WILL CONTINUE INTO FRIDAY WITH EVEN
WARMER TEMPERATURES EXPECTED IN THE UPPER 30S TO UPPER 40S.
A POTENT UPPER LEVEL SYSTEM CONSISTING OF SEVERAL STRONG SHORT
WAVES ROTATING AROUND THE CORE WILL BEGIN TO MOVE OVER CALIFORNIA
ON FRIDAY. ANOTHER SHORT WAVE UNDERCUTTING THE SYSTEM WILL PUSH
OUT AHEAD AND ARRIVE OVER NEBRASKA AND IOWA BY FRIDAY NIGHT. AN
INCREASING LOW LEVEL JET AND ASSOCIATED STRONG THETA-E ADVECTION
ALONG WITH THE QG FORCING FROM THE UPPER WAVE WILL HELP SHOWERS
AND A FEW THUNDERSTORMS DEVELOP ACROSS MAINLY CENTRAL AND WESTERN
IOWA. OVERNIGHT LOW TEMPERATURES ARE EXPECTED TO BE AT OR ABOVE
FREEZING WITH LOW LEVEL MOISTURE SURGE BRINGING DEWPOINTS IN THE
3OS TO THE AREA. THE FORECAST AREA WILL BE IN THE WARM SECTOR
THROUGH THE DAY SATURDAY. THE PRIMARY UPPER LEVEL SYSTEM WILL LIFT
INTO THE MIDWEST SATURDAY NIGHT INTO SUNDAY. THE ECMWF IS A BIT
FASTER WITH THE SFC FEATURES WITH THE COLD FRONT DROPPING THROUGH
MUCH OF CENTRAL IOWA BY 12Z SUNDAY WHILE THE GFS IS A BIT SLOWER.
ANY PRECIPITATION WILL SWITCH OVER TO SNOW BEHIND THE COLD FRONT
AS PROFILES COOL. SOME SNOW ACCUMULATIONS WILL BE POSSIBLE. COLD
ADVECTION WILL BE PROMINENT MUCH OF THE DAY SUNDAY WITH HIGH
TEMPERATURES EARLY IN THE DAY. 850 MB TEMPERATURES BY 12Z MONDAY
WILL BE -8C TO -10C ACROSS MUCH OF THE AREA AND HAVE CONTINUED THE
COOLING TREND INTO MONDAY. SOME MODERATION FOR THE END OF THE
PERIOD WITH LOW CHANCES FOR PRECIPITATION.
&&
.AVIATION...06/06Z
MVFR STRATUS CONTINUES TO STREAM ACROSS THE STATE FROM THE NNW WITH
A FEW PATCHES OF VFR CONDITIONS SCATTERED ABOUT IOWA AND MINNESOTA.
THE VFR CEILINGS HAVE BEEN DECREASING IN COVERAGE OVER THE LAST
COUPLE OF HOURS SO HAVE NOT MENTIONED ANYTHING HIGHER THAN MVFR IN
THE TAF PACKAGE. HIGH IFR CEILINGS ARE POSSIBLE ACROSS THE NORTH
TONIGHT AS WELL. HAVE CONTINUED TO PUSH BACK THE CLEARING OF THE
STRATUS INTO THE MID MORNING TOMORROW GIVEN THE LARGE SHIELD OF
STRATUS EXTENDING UPSTREAM INTO MN AND MANITOBA.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...PODRAZIK
LONG TERM...DONAVON
AVIATION...KS
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1034 AM EST WED MAR 6 2013
.SYNOPSIS...
SNOW WILL DIMINISH AS LOW PRESSURE CONTINUES MOVING EASTWARD.
&&
.NEAR TERM /THROUGH TONIGHT/...
THE BAND OF SNOW ASSOCIATED WITH THE DEFORMATION ZONE CONTINUES TO
DIMINISH AS IT SHIFTS TO THE SOUTH OVER SW PA THIS MORNING.
THUS...HAVE CANCELLED THE ADVISORY FOR BUTLER AND ARMSTRONG
COUNTIES. THE HRRR SEEMS TO BE HANDLING THIS BAND WELL SO HAVE
ADJUSTED POPS ACCORDINGLY BASED OFF OF CURRENT RADAR AND HRRR
MODEL TRENDS. WITH DEFORMATION SNOWS LASTING LONGEST OVER THE
RIDGES...THINK THEY WILL EASILY SEE ANOTHER 2-5 INCHES OF SNOW AND
WILL KEEP THE WARNING GOING FOR NOW. OTHERWISE...ONLY SMALL
ADJUSTMENTS WERE NEEDED TO TEMPS...DEWPOINTS...AND WINDS THROUGH
THE AFTERNOON.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY/...
STILL TRYING TO GET A GOOD HANDLE OF SNOW POSSIBILITIES FOR
THURSDAY INTO THURSDAY NIGHT. MODELS ARE NOW SHOWING A WEAK UPPER
LEVEL WAVE DROPPING ACROSS ONTARIO...WITH THE BEST MOISTURE AND
DYNAMICS EXPECTED TO CROSS NEW YORK AND CENTRAL/EASTERN
PENNSYLVANIA. HAVE ADDED A SLIGHT CHANCE OF PRECIPITATION INTO THE
FORECAST NORTH AND EAST OF PITTSBURGH. WIND DIRECTIONS WILL BE
CRITICAL TO WHETHER ANY FLAKES ARE SEEN IN THE UPSLOPE REGIONS OF
PA/WV/MD. CURRENTLY HAVE A NORTHWEST WIND WHICH WOULD ALLOW FOR
SOME VERY LIGHT UPSLOPE SNOW...BUT IF WIND DIRECTIONS ARE MORE
NORTHERLY SUCH AS SHOWN IN THE NAM...WOULD NOT EXPECT TO SEE ANY
SNOW TO THE SOUTH. HIGH PRESSURE WILL THEN BUILD IN FOR THURSDAY
NIGHT AND FRIDAY...BRINGING DRY CONDITIONS TO ALL LOCATIONS.
TEMPERATURES WILL RISE A FEW DEGREES FROM WEDNESDAY READINGS...BUT
STILL REMAIN A COUPLE OF DEGREES BELOW NORMAL.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
MODELS ARE IN GOOD AGREEMENT WITH DEPICTIONS OF SATURDAY WEATHER...BUT
DIVERGENT SOLNS QUICKLY ERODE LONG TERM FORECAST CONFIDENCE. FAIRLY
BROAD AND AMPLIFIED ERN CONUS RIDGE IS EXPECTED TO BE BROKEN
DOWN DURING THE PD...ALBEIT WITH QNABLE TIMING.
PERSISTENCE/COLLABORATED LONG TERM PROGNOSIS THUS FEATURES TEMPS
AT...OR ABOVE THE SEASONAL AVERAGES ACCOMPANIED BY GRADUALLY
INCRSG PCPN PROBABILITIES TO NR CLIMO NMBRS THRU EARLY NXT WEEK.
&&
.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
AREA OF LINGERING SN BTN PIT...LBE AND MGW WL GRADUALLY DIMINISH BY
THIS AFTN. VFR CONDITIONS MAY BRIEFLY RTN AS SBSDNC INCRS IN THE
WAKE OF THE EXITING LOW...BUT MORE RESTRICTION IN STRATOCU...AND
POSSIBLY SOME FOG ARE ANTICIPATED OVRNGT AND INTO EARLY THURSDAY.
.OUTLOOK.../THURSDAY THROUGH SATURDAY/...
GENL VFR CONDITIONS ARE ANTICIPATED FOR THE END OF THE WEEK AS HIGH
PRES BLDS OVR THE REGION.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER STORM WARNING UNTIL 7 PM EST THIS EVENING FOR MDZ001.
OH...NONE.
PA...WINTER STORM WARNING UNTIL 5 PM EST THIS AFTERNOON FOR PAZ021-
029-031-073-075.
WINTER STORM WARNING UNTIL 7 PM EST THIS EVENING FOR PAZ074-
076.
WINTER WEATHER ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
PAZ023.
WV...WINTER STORM WARNING UNTIL 5 PM EST THIS AFTERNOON FOR WVZ021-
022.
WINTER STORM WARNING UNTIL 7 PM EST THIS EVENING FOR WVZ023-
041.
&&
$$
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
942 AM EST WED MAR 6 2013
.SYNOPSIS...
STRONG LOW PRESSURE WILL IMPACT THE AREA THROUGH TONIGHT. THE LOW
WILL MOVE AWAY FROM THE AREA THURSDAY. HIGH PRESSURE WILL BUILD
OVERHEAD LATE IN THE WEEK AND PERSIST THROUGH THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
STACKED LOW PRESSURE OVER THE HAMPTONS WILL SLOWLY PUSH
OFFSHORE THROUGH THIS AFTERNOON. WINDS HAVE SHIFTED TO THE NNE
OVER THE I95 CORRIDOR...AND PRECIPITATION HAS CHANGED OVER TO
HEAVY SNOW. AREAS TO THE SOUTHEAST OF BALTIMORE/DC SHOULD CHANGE
OVER TO SNOW AS WELL OVER THE NEXT SEVERAL HOURS. GIVEN THE
DURATION OF RAINFALL OVER THE REGION SO FAR THIS MORNING...HAVE
LOWERED SNOW TOTALS ALONG AND EAST OF I-95...BUT MAINTAINING
WINTER STORM WARNING FOR THE ENTIRE AREA.
ALSO ADDED ISOLATED THUNDER TO AREAS S OF THE DC METRO. CONVECTION
CURRENTLY OCCURRING OVER SE VA MAY ROTATE NWD INTO THE PIEDMONT AND
SRN MD. ONE STRIKE WAS NOTED EARLIER OVER CULPEPER COUNTY...AND
FORECAST SOUNDINGS INDICATE ELEVATED INSTABILITY.
PRECIP IS EXPECTED TO CONTINUE THROUGH THE AFTERNOON. BANDS OF
HEAVIER PRECIP EXPECTED TO ROTATE AROUND THE NORTH AND WEST SIDE
OF THE LOW...AS LIFT CONTINUES TO BE STRONG. HRRR ADVERTISES ONE
SUCH BAND ROTATING AROUND THE DC METRO AREA THROUGH LATE
AFTERNOON...AND OTHER BANDING ACTIVITY ALONG AND WEST OF THE BLUE
RIDGE WHERE SIGNIFICANT SNOWFALL HAS ALREADY FALLEN.
A RAPID DECREASE IN SNOW INTENSITIES WILL OCCUR TOWARD THE
MIDDLE/LATE EVE HRS FROM WEST-TO-EAST AS THE LOW ACCELERATES OFF THE
COAST AND DISSIPATES THE LARGER SNOW BAND OVER THE REGION. ONLY
FLURRIES AND RESIDUAL LIGHT POCKETS OF SNOW CONTINUE LATE THIS EVE
BUT ALSO DISSIPATE INTO THE OVERNIGHT HRS. AS CONDITIONS DRY
OUT...WINDS WILL REMAIN. TEMPS WON`T DROP TOO MUCH FURTHER BELOW
FREEZING BUT WILL CHILLS WILL...AS A DRIER BITING NW WIND TAKES OVER
INTO THE EARLY MRNG HRS THU.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY/...
COASTAL LOW WILL BE WELL OFFSHORE THURSDAY MORNING...BUT IS FORECAST
TO MOVE LITTLE AND MEANDER ACROSS THE WESTERN ATLANTIC THROUGH
FRIDAY. THIS WILL KEEP THE CWA IN A NORTHERLY FLOW DURING THIS TIME.
ANY LINGERING SNOWFALL ASSOCIATED WITH WRAP AROUND/DEFORMATION
SHOULD MOVE EAST OF THE BAY THURSDAY MORNING...LEAVING A DRY
FORECAST FOR THE REST OF THE DAY SAVE FOR SOME SNOW SHOWERS ON THE
WESTERN SLOPES. IN FACT...PARTIAL SUNSHINE MAY EVEN BE SEEN IN THE
AFTERNOON WHICH WILL HELP TO MELT SOME SNOW. BUT WITH
SNOWPACK...OPTED REMAIN BELOW MOS GUIDANCE FOR MAXIMA. KEPT THE
SAME IDEA FOR MINIMA THURSDAY NIGHT...ESPECIALLY WITH MODELS
SHOWING CLEAR TO PARTLY CLOUDY SKIES.
NAM IS MORE AGGRESSIVE TRYING TO WRAP AROUND MORE CLOUDS AND EVEN
SOME PRECIP ACROSS THE NORTHEAST PORTION OF THE CWA FRIDAY.
CONFIDENCE IS LOW ON PRECIP BEING ABLE TO WRAP BACK THIS FAR WEST
SO KEPT DRY FORECAST...BUT DID INCLUDE MORE CLOUDS.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
THE LOW WILL GRADUALLY PULL AWAY FROM THE AREA THIS WEEKEND AS SFC
HIPRES/UPPER RIDGE BUILDS ACROSS THE ERN CONUS. A MODERATING TREND
CAN BE EXPECTED THROUGH ERY NEXT WEEK. MAX TEMPS WILL BE IN 40S
WHERE A DEEPER SNOW PACK PERSISTS AND POSSIBLY 50S FARTHER EAST NEAR
I-95.
EXTENDED-RANGE GUIDANCE HAS TRENDED SLOWER WITH THE NEXT LOPRES
SYSTEM AND COLD FRONT...WHICH NOW LOOKS TO APPROACH LATE MON OR TUE.
GIVEN LATEST TRACK OF SFC LOW...DEEP WARM SLY FLOW IN PRE-FRONTAL
WARM SECTOR MAY LEAD TO SIGNIFICANT MELTING OF SNOW PACK AS HIGHS
COULD POTENTIALLY REACH THE UPPER 40S AND 50S MON/TUE.
&&
.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
SNOW CONTINUES THROUGH TODAY. VSBYS WILL FLUCTUATE FROM MVFR TO
LIFR AS HEAVIER BANDS OF SNOW MOVE THROUGH THE TERMINALS. INTENSE
SNOWFALL RATES...GUSTY WINDS AND REDUCED VSBYS WILL BE CENTERED
OVER THE I-95 CORRIDOR AND BACK TOWARD THE BLUE RIDGE BETWEEN
THROUGH 20Z...TAPERING OFF TOWARD THE END OF THAT PERIOD. SNOW
WILL BEGIN TO DISSIPATE DURING THE EVE HRS...BUT WINDS WILL REMAIN
BREEZY OUT OF THE NW ALL NIGHT AND INTO THU.
PRECIP SHOULD SHUT OFF BY EARLY THURSDAY MORNING...WITH A RETURN
TO VFR CONDITIONS FOR THURSDAY. MAIN IMPACT WILL BE FROM GUSTY
NORTHWEST WINDS WHICH MAY LINGER INTO FRIDAY. QUIET WITH HIGH
PRESSURE THIS WEEKEND.
&&
.MARINE...
GALE FORCE WIND GUSTS CONTINUE TODAY...AS A SFC LOW SLOWLY MOVES
EWD OFF THE COAST NEAR NORFOLK. SOLID GALE GUSTS WILL STREAM DOWN THE MAIN
CHANNEL OF THE BAY AND TP RVR. THIS WILL CONTINUE INTO THE LATE
NIGHT HRS...AND WINDS WILL STILL GUST IN THE GALE RANGE OVERNIGHT.
WINDS BECOME NORTHWEST BY THURSDAY...AND WITH FORECAST GRADIENT
HAVE EXTEND GALES FOR MUCH OF THE MARINE AREA INTO THURSDAY. SCA
CONDITIONS ARE LIKELY TO LINGER THROUGH THE END OF THE WEEK.
&&
.HYDROLOGY...
WILL BE WATCHING SNOWMELT OVER THE NEXT SEVERAL DAYS. ALREADY HAVE
NUMEROUS REPORTS OF OVER A FOOT OF SNOW. A GRADUAL MELT SEEMS MOST
LIKELY BUT WILL HAVE TO KEEP AN EYE ON IT THROUGH THE END OF THE
WEEK.
&&
.TIDES/COASTAL FLOODING...
WINDS ARE NOW OUT OF THE NORTHEAST IN THE TIDAL ZONE...BUT OUT OF
THE EAST JUST ACROSS THE EASTERN SHORE. LEWISETTA IS OVERACHIEVING
THE MODEL FORECAST...NEAR MODERATE FLOOD LEVEL. COASTAL FLOOD
ADVISORY IS STILL OUT FOR THE WESTERN SHORE EXCEPT HARFORD...AND THE
ST. MARYS PORTION OF THE TIDAL POTOMAC. NEW GUIDANCE FROM MARFC
TAKES THE UPPER POTOMAC TO MINOR FLOOD ALSO LATER TODAY. NOT SO SURE
ABOUT THAT JUST YET GIVEN THE NORTH WIND...BUT WILL MONITOR FOR THE
NEED TO ADD ANYTHING TO THE ADVISORY.
AS WINDS TURN NORTHERLY LATE TODAY...GIVEN THEIR EXPECTED
STRENGTH...THERE WILL BE A SHARP BLOWOUT TIDE...PERHAPS COMPLETELY
DAMPENING OUT THE WEDNESDAY NIGHT HIGH TIDE ALTOGETHER IN THE UPPER
BAY. FORECAST MODEL STILL SHOWS A LITTLE WATER TRAPPING IN THE
LOWERMOST TIDAL POTOMAC...AND WILL HAVE TO WATCH TRENDS TO SEE IF
ANOTHER ADVISORY IS NEEDED FOR ST. MARYS COUNTY.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...WINTER STORM WARNING UNTIL 3 AM EST THURSDAY FOR DCZ001.
MD...WINTER STORM WARNING UNTIL MIDNIGHT EST TONIGHT FOR MDZ003-501-
502.
WINTER STORM WARNING UNTIL 3 AM EST THURSDAY FOR MDZ004>007-
009>011-013-014-016>018.
COASTAL FLOOD ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR
MDZ014-017-018.
COASTAL FLOOD ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
MDZ011.
VA...WINTER STORM WARNING UNTIL MIDNIGHT EST TONIGHT FOR VAZ025>031-
503-504.
WINTER STORM WARNING UNTIL 3 AM EST THURSDAY FOR VAZ036>040-
042-050>057-501-502.
WV...WINTER STORM WARNING UNTIL MIDNIGHT EST TONIGHT FOR WVZ050>053-
055-501>506.
MARINE...GALE WARNING UNTIL 6 PM EST THURSDAY FOR ANZ530>534-537>543.
SMALL CRAFT ADVISORY FROM 6 AM TO 6 PM EST THURSDAY FOR ANZ535-
536.
GALE WARNING UNTIL 6 AM EST THURSDAY FOR ANZ535-536.
&&
$$
SYNOPSIS...BPP/GMS
NEAR TERM...GMS/KCS
SHORT TERM...BPP
LONG TERM...JRK
AVIATION...KCS/BPP/JRK
MARINE...JRK/BPP/KCS
HYDROLOGY...JE
TIDES/COASTAL FLOODING...JE
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
837 AM EST WED MAR 6 2013
.SYNOPSIS...
STRONG LOW PRESSURE WILL IMPACT THE AREA THROUGH TONIGHT. THE LOW
WILL MOVE AWAY FROM THE AREA THURSDAY. HIGH PRESSURE WILL BUILD
OVERHEAD LATE IN THE WEEK AND PERSIST THROUGH THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AT 0830AM...QUICK UPDATE MADE TO MORNING FCST BASED ON CURRENT
RADAR/OBS. RAIN/SNOW LINE IS JUST TO SOUTHEAST OF A LINE FROM
BWI/ADW/DCA. SOUTHEAST OF THIS LINE...MOSTLY RAIN IS FALLING WITH
SURFACE TEMPS IN UPPER 30S...TO EVEN LOW 40S OVER SRN MD.
LOW PRESSURE IS NOW OVER THE NORFOLK METRO AREA...WITH AN EASTERLY
WIND ADVECTING MARINE AIR OVER SRN MD. AS THE BOTH THE SURFACE AND
UPPER LOW MOVE TOWARDS THE NORTH DURING THE DAY TODAY...WINDS ARE
EXPECTED TO BECOME MORE NORTHERLY AND DRAW IN COOLER AIR. FOR THIS
REASON...STILL EXPECTING A CHANGEOVER TO SNOW ALONG AND EAST OF
THE I-95 CORRIDOR. ADJUSTED SNOWFALL TOTALS DOWN S AND E OF
BWI/DCA BASED ON LOWER SNOW ACCUM IN THE MORNING. ALSO ADJUSTED
TOTALS ALONG AND W OF THE BLUE RIDGE BASED ON REPORTS.
ALSO ADDED ISOLATED THUNDER TO AREAS S OF THE DC METRO. CONVECTION
CURRENTLY OCCURRING OVER SE VA MAY ROTATE NWD INTO THE PIEDMONT AND
SRN MD. ONE STRIKE WAS NOTED EARLIER OVER CULPEPER COUNTY...AND
FORECAST SOUNDINGS INDICATE ELEVATED INSTABILITY.
PREVIOUS DISCUSSION....
THE TRANSITION BETWEEN PHASES OF THIS INTENSE AND IMPACTFUL
INCOMING SNOWSTORM IS FULLY UNDERWAY. THE INITIAL SFC LOW THAT
DROPPED DOWN FROM THE NRN PLAINS INTO THE UPPER MIDWEST IS ABOUT
TO BE PHASED-OUT. THE NEWER AND STRONGER LOW CURRENTLY OVER THE
RALEIGH NC AREA WILL CREATE A SNOWY AND HAZARDOUS WEDNESDAY FOR
MUCH OF THE MID-ATLC. THE NEXT SEVERAL HOURS WILL BE THE CRITICAL
TRANSITION PERIOD AS THIS LOW INTENSIFIES AND ROTATES DUE NE
TOWARD THE LOWER TIP OF THE DELMARVA PENINSULA AND DEVELOPS HEAVY
SNOW BAND ACROSS THE NWRN QUADRANT OF THE LOW DURING THE DAYTIME
HRS.
THROUGH DAYBREAK...
A REGIONAL VIEW OF THE RADAR RETURNS SHOWS THAT SNOW STILL AFFECTING
MUCH OF THE UPPER MIDWEST...FROM CNTRL IN TO THE APLCNS...BUT THIS
AREA OF PRECIP REGION WILL DISSIPATE IN THE NEXT FEW HRS. ONLY
POCKETS OF HIGHER ELEVATION UPSLOPE SNOW WILL CONTINUE ALONG THE
APLCN CHAIN.
THE FIRST PHASE OF THE SYSTEM THAT BROUGHT LIGHT TO MODERATE SNOW
OVER THE ENTIRE REGION IN JUST THE PAST FEW HOURS IS JUST THE START.
ABOUT A HALF-FOOT OF SNOW HAS ALREADY FALLEN OVER THE HIGHER TERRAIN
OF THE CNTRL APLCNS...TOWARD THE BLUE RIDGE. A FEW INCHES HAVE
BEEN COMMON OVER THE SWRN QUADRANT OF THE CWA THRU 2-3AM. THE
HEAVIER BANDS THAT BROUGHT THIS ACTIVITY ARE NOW SPREADING ACROSS
THE DC/BALT AND THE PIEDMONT AREAS. THIS ACTIVITY WILL CREATE THE
FIRST LAYER OF SNOW AND ALLOW FOR THE INITIAL BASE FOR ACCUMULATIONS
FROM THE SECOND PHASE OF THE STORM.
WINDS HAVE BEEN INTERMITTENTLY INCREASED...NORMALLY W/ SOME OF THE
HEAVIER BANDS BUT THEN DROP BACK DOWN TO 5-10MPH. THESE LOWER WIND
SPEEDS ARE ALLOWING FOR THE RELATIVELY HIGHER VISIBILITIES IN THE
1-2SM RANGE. THIS WILL CHANGE AS WINDS INCREASE AND SNOW
INTENSITIES INCREASE. DETERMINISTIC NAM AND GFS RUNS STILL BULLISH
ON QPF...SO THE CURRENT FORECAST IS A GOOD MIX OF NEAR TERM HI-RES
GUIDANCE...INCLUDING LOCAL VERSION OF THE VARIOUS WRF MEMBERS AND
ESPC THE HRRR WHICH HAS DONE WELL W/ INITIALIZING OVER THE FIRST
PART OF THIS EVENT.
DAYBREAK THROUGH MIDDAY...
IF THEY HAVEN`T ALREADY BY DAYBREAK - CONDITIONS WILL DETERIORATE
RAPIDLY ACROSS MOST - IF NOT ALL - OF THE CWA. LOCALIZED AREAS WILL
RECEIVE BRIEF INTENSE SNOWFALL RATES OF 1-2 INCHES PER HR...POSSIBLY
HIGHER. NOW THAT THE LOW IS ON THE DOORSTEP AND NEAR-TERM GUIDANCE
HAS BEEN INITIALIZING W/ THIS DATA...SOME OF THE HI-RES MEMBERS HAVE
STARTED TO DEPICT ONE LARGE ENCOMPASSING SNOW BAND - ORIENTED ALONG
THE I-95 CORRIDOR BUT STRETCHING OVER THE ENTIRETY OF THE
PIEDMONT/COASTAL COUNTIES...TAPERING OFF TOWARD THE BLUE RIDGE AND
APLCNS. WITHIN THIS LARGER BAND WILL BE THE DYNAMIC HEAVIER BANDS W/
THE HIGHER INTENSITIES AND LOW VISIBILITIES.
WINDS AROUND THIS SECTOR OF THE STORM WILL BE STRENGTHENING W/ SUST
SPEEDS IN THE 15-25MPH RANGE AND PEAK GUSTS IN THE 30-40MPH RANGE.
NEAR-WHITEOUT CONDITIONS ARE STILL IN QUESTION...IN TERMS OF AREA
AND DURATION. THERE WILL BE BRIEF PERIODS OF NEAR-WHITEOUT
CONDITIONS BUT AS FAR WIDESPREAD AND LONG-LIVED DURATIONS...
CONFIDENCE IS LOWER. REGARDLESS...THE HEAVY-WET SNOW AND GUSTY WINDS
WILL CREATE DANGEROUS AND NEAR-IMPOSSIBLE TRAVEL AT TIMES.
MIDDAY THROUGH LATE TONIGHT...
THE HEIGHT OF SNOWFALL RATES AND INTENSITIES ACROSS THE I-95
CORRIDOR...THE METRO AREAS AND THE VA/MD PIEDMONT IS EXPECTED TO BE
FROM THE LATE MRNG INTO THE EARLY AFTN HRS. AT THIS TIME...THE LOW
WILL BE MOVING AWAY FROM THE OCEAN CITY MD AREA...PULLING AWAY FROM
THE COAST AND STARTING TO TAKE THE PRECIP ALONG WITH IT.
SEVERAL ADDITIONAL INCHES OF SNOW WILL ACCUMULATE ACROSS THE
REGION...BRINGING TOTALS TO LIKELY OVER A FOOT ACROSS MUCH OF THE
SHEN VLY AND BETWEEN ONE-TO-TWO FT ALONG THE SURROUNDING
RIDGELINES...JUST UNDER A FOOT ACROSS THE VA PIEDMONT AND JUST INTO
N CNTRL MD...MORE OF A 6-12 INCH SPREAD ALONG THE I-95 CORRIDOR AND
A RAIN/SNOW MIX ALONG THE WRN BAYSHORE COUNTIES AND SRN MD - THOUGH
4-8 INCH TOTAL STILL POSSIBLE AT THE TAIL END OF STORM SYSTEM
LATER IN THE AFTN/EVE.
A RAPID DECREASE IN SNOW INTENSITIES WILL OCCUR TOWARD THE
MIDDLE/LATE EVE HRS FROM WEST-TO-EAST AS THE LOW ACCELERATES OFF THE
COAST AND DISSIPATES THE LARGER SNOW BAND OVER THE REGION. ONLY
FLURRIES AND RESIDUAL LIGHT POCKETS OF SNOW CONTINUE LATE THIS EVE
BUT ALSO DISSIPATE INTO THE OVERNIGHT HRS. AS CONDITIONS DRY
OUT...WINDS WILL REMAIN. TEMPS WON`T DROP TOO MUCH FURTHER BELOW
FREEZING BUT WILL CHILLS WILL...AS A DRIER BITING NW WIND TAKES OVER
INTO THE EARLY MRNG HRS THU.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY/...
COASTAL LOW WILL BE WELL OFFSHORE THURSDAY MORNING...BUT IS FORECAST
TO MOVE LITTLE AND MEANDER ACROSS THE WESTERN ATLANTIC THROUGH
FRIDAY. THIS WILL KEEP THE CWA IN A NORTHERLY FLOW DURING THIS TIME.
ANY LINGERING SNOWFALL ASSOCIATED WITH WRAP AROUND/DEFORMATION
SHOULD MOVE EAST OF THE BAY THURSDAY MORNING...LEAVING A DRY
FORECAST FOR THE REST OF THE DAY SAVE FOR SOME SNOW SHOWERS ON THE
WESTERN SLOPES. IN FACT...PARTIAL SUNSHINE MAY EVEN BE SEEN IN THE
AFTERNOON WHICH WILL HELP TO MELT SOME SNOW. BUT WITH
SNOWPACK...OPTED REMAIN BELOW MOS GUIDANCE FOR MAXIMA. KEPT THE
SAME IDEA FOR MINIMA THURSDAY NIGHT...ESPECIALLY WITH MODELS
SHOWING CLEAR TO PARTLY CLOUDY SKIES.
NAM IS MORE AGGRESSIVE TRYING TO WRAP AROUND MORE CLOUDS AND EVEN
SOME PRECIP ACROSS THE NORTHEAST PORTION OF THE CWA FRIDAY.
CONFIDENCE IS LOW ON PRECIP BEING ABLE TO WRAP BACK THIS FAR WEST
SO KEPT DRY FORECAST...BUT DID INCLUDE MORE CLOUDS.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
THE LOW WILL GRADUALLY PULL AWAY FROM THE AREA THIS WEEKEND AS SFC
HIPRES/UPPER RIDGE BUILDS ACROSS THE ERN CONUS. A MODERATING TREND
CAN BE EXPECTED THROUGH ERY NEXT WEEK. MAX TEMPS WILL BE IN 40S
WHERE A DEEPER SNOW PACK PERSISTS AND POSSIBLY 50S FARTHER EAST NEAR
I-95.
EXTENDED-RANGE GUIDANCE HAS TRENDED SLOWER WITH THE NEXT LOPRES
SYSTEM AND COLD FRONT...WHICH NOW LOOKS TO APPROACH LATE MON OR TUE.
GIVEN LATEST TRACK OF SFC LOW...DEEP WARM SLY FLOW IN PRE-FRONTAL
WARM SECTOR MAY LEAD TO SIGNIFICANT MELTING OF SNOW PACK AS HIGHS
COULD POTENTIALLY REACH THE UPPER 40S AND 50S MON/TUE.
&&
.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
A SNOWSTORM FOR MUCH OF THE AREA TODAY. THE PAST SEVERAL HRS HAS
BEEN THE WARM-UP FOR THE MORE INTENSE VERSION LATER THIS MRNG AND
AFTN. SOLID IFR CONDS ALREADY COVERING THE REGION W/ A FEW LIFR OBS
SCATTERED ABOUT...UNDER THE HEAVIER SNOW BANDS. THE RESPONSIBLE SFC
LOW IS STILL OVER ERN NC BUT WILL MOVE TOWARD THE NORFOLK VA AREA IN
THE COMING HRS...INTENSIFY AND CREATE A STRONGER LOW LEVEL WIND
FIELD BACK ACROSS MD/NRN VA. INTENSE SNOWFALL RATES...GUSTY WINDS
AND REDUCED VSBYS WILL BE CENTERED OVER THE I-95 CORRIDOR AND BACK
TOWARD THE BLUE RIDGE BETWEEN THROUGH 20Z...TAPERING OFF TOWARD
THE END OF THAT PERIOD. SNOW WILL BEGIN TO DISSIPATE DURING THE
EVE HRS...BUT WINDS WILL REMAIN BREEZY OUT OF THE NW ALL NIGHT AND
INTO THU.
PRECIP SHOULD SHUT OFF BY EARLY THURSDAY MORNING...WITH A RETURN
TO VFR CONDITIONS FOR THURSDAY. MAIN IMPACT WILL BE FROM GUSTY
NORTHWEST WINDS WHICH MAY LINGER INTO FRIDAY. QUIET WITH HIGH
PRESSURE THIS WEEKEND.
&&
.MARINE...
GALE FORCE WIND GUSTS WILL BECOME MORE COMMON HEADING INTO THE MRNG
HRS TODAY...AS A SFC LOW MOVES FROM NRN NC TOWARD THE DELMARVA
REGION. BREEZY E-NELY WINDS WILL BECOME INTENSE NLY WINDS WHILE THE
LOW IS MOVING OFF THE COAST LATER THIS MRNG. SOLID GALE GUSTS WILL
STREAM DOWN THE MAIN CHANNEL OF THE BAY AND TP RVR. THIS WILL
CONTINUE INTO THE LATE NIGHT HRS...AND WINDS WILL STILL GUST IN THE
GALE RANGE OVERNIGHT.
WINDS BECOME NORTHWEST BY THURSDAY...AND WITH FORECAST GRADIENT
HAVE EXTEND GALES FOR MUCH OF THE MARINE AREA INTO THURSDAY. SCA
CONDITIONS ARE LIKELY TO LINGER THROUGH THE END OF THE WEEK.
&&
.HYDROLOGY...
MODEL GUIDANCE REMAINS REMARKABLY CONSISTENT WITH A QPF BULLSEYE IN
THE RAPPAHANNOCK BASIN. AROUND TWO INCHES OF LIQUID/LIQUID EQUIV
PRECIPITATION IS LIKELY THROUGH MUCH OF THAT BASIN. IT LOOKS LIKE
THE MAJORITY OF THAT WILL WIND UP BEING FROM SNOW ESPECIALLY IN
THE UPPER PART. IN ADDITION...SFC TEMPS AND SOIL TEMPS ARE AND
WILL REMAIN ABOVE FREEZING OUTSIDE THE HIGHER ELEVATIONS...SO
THERE WILL BE SOME SOIL INFILTRATION INITIALLY FROM RAIN...LIQUID
FROM SNOW...OR BOTH. THEN WE HAVE TO LOOK AT HOW QUICKLY THE SNOW
MELTS...AND HOW LONG IT TAKES TO START MELTING THE MOUNTAIN SNOWS
TO ADD TO THE PICTURE. THE MOST LIKELY SCENARIO IS FOR THERE TO BE
A GRADUAL MELT...WHICH WOULD NOT POSE MUCH OF A FLOOD THREAT...BUT
THE AFOREMENTIONED UNCERTAINTIES LEND THEMSELVES TO KEEPING AN EYE
ON THE SITUATION THROUGH THE END OF THE WEEK.
&&
.TIDES/COASTAL FLOODING...
ANOMALIES HAVE TURNED POSITIVE...CLOSE TO 1 FT ABOVE NORMAL AT 3 AM
ALONG THE WESTERN SHORE OF THE BAY. WITH EASTERLY FLOW PERSISTING
THIS MORNING...ANOMALIES WILL CONTINUE TO CLIMB POSSIBLY ON THE
ORDER OF 1.5 TO 2 FT ABOVE NORMAL. THIS WILL PRODUCE MINOR TIDAL
FLOODING ALONG THE WESTERN SHORE OF THE CHESAPEAKE BAY UP THROUGH AT
LEAST ANNE ARUNDEL COUNTY...AND CONFIDENCE IS INCREASING OF THE
MINOR THRESHOLD BEING REACHED TOWARD BALTIMORE DURING HIGH TIDE.
CONFIDENCE DECREASES NORTH OF HERE WITH AN EAST WIND BECOMING
NORTHEAST BY HIGH TIDE TIME. SAME GOES FOR THE UPPER TIDAL
POTOMAC...SO WILL REFRAIN FROM ADVISORY IN THESE AREAS DO TO LOWER
CONFIDENCE BUT WILL NEED TO BE WATCHED.
LATER THIS AFTERNOON AND EVENING WHEN WINDS DO TURN
NORTHERLY...THERE WILL BE A SHARP BLOWOUT TIDE...PERHAPS
COMPLETELY DAMPENING OUT THE WEDNESDAY NIGHT HIGH TIDE ALTOGETHER
IN THE UPPER BAY. FORECAST MODEL SHOWS A LITTLE WATER TRAPPING IN
THE LOWERMOST TIDAL POTOMAC THAT KEEPS LEVELS ELEVATED FOR THE
WEDNESDAY EVENING CYCLE THERE. WILL HAVE TO KEEP AN EYE ON THAT.
WINDS TURN OUT OF THE NORTHWEST AFTER THAT...WHICH SHOULD MAKE
EVERYTHING DROP SIGNIFICANTLY.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...WINTER STORM WARNING UNTIL 3 AM EST THURSDAY FOR DCZ001.
MD...WINTER STORM WARNING UNTIL MIDNIGHT EST TONIGHT FOR MDZ003-501-
502.
WINTER STORM WARNING UNTIL 3 AM EST THURSDAY FOR MDZ004>007-
009>011-013-014-016>018.
COASTAL FLOOD ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR
MDZ014-017-018.
COASTAL FLOOD ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
MDZ011.
VA...WINTER STORM WARNING UNTIL MIDNIGHT EST TONIGHT FOR VAZ025>031-
503-504.
WINTER STORM WARNING UNTIL 3 AM EST THURSDAY FOR VAZ036>040-
042-050>057-501-502.
WV...WINTER STORM WARNING UNTIL MIDNIGHT EST TONIGHT FOR WVZ050>053-
055-501>506.
MARINE...GALE WARNING UNTIL 6 PM EST THURSDAY FOR ANZ530>534-537>543.
SMALL CRAFT ADVISORY FROM 6 AM TO 6 PM EST THURSDAY FOR ANZ535-
536.
GALE WARNING UNTIL 6 AM EST THURSDAY FOR ANZ535-536.
&&
$$
SYNOPSIS...BPP/GMS
NEAR TERM...GMS/KCS
SHORT TERM...BPP
LONG TERM...JRK
AVIATION...JRK/BPP/GMS
MARINE...JRK/BPP/GMS
HYDROLOGY...
TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
832 AM EST WED MAR 6 2013
.SYNOPSIS...
STRONG LOW PRESSURE WILL IMPACT THE AREA THROUGH TONIGHT. THE LOW
WILL MOVE AWAY FROM THE AREA THURSDAY. HIGH PRESSURE WILL BUILD
OVERHEAD LATE IN THE WEEK AND PERSIST THROUGH THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AT 0830AM...QUICK UPDATE MADE TO MORNING FCST BASED ON CURRENT
RADAR/OBS. RAIN/SNOW LINE IS JUST TO SOUTHEAST OF A LINE FROM
BWI/ADW/DCA. SOUTHEAST OF THIS LINE...MOSTLY RAIN IS FALLING WITH
SURFACE TEMPS IN UPPER 30S...TO EVEN LOW 40S OVER SRN MD.
LOW PRESSURE IS NOW OVER THE NORFOLK METRO AREA...WITH AN EASTERLY
WIND ADVECTING MARINE AIR OVER SRN MD. AS THE BOTH THE SURFACE AND
UPPER LOW MOVE TOWARDS THE NORTH DURING THE DAY TODAY...WINDS ARE
EXPECTED TO BECOME MORE NORTHERLY AND DRAW IN COOLER AIR. FOR THIS
REASON...STILL EXPECTING A CHANGEOVER TO SNOW ALONG AND EAST OF
THE I-95 CORRIDOR. ADJUSTED SNOWFALL TOTALS DOWN S AND E OF
BWI/DCA BASED ON LOWER SNOW ACCUM IN THE MORNING. ALSO ADJUSTED
TOTALS ALONG AND W OF THE BLUE RIDGE BASED ON REPORTS.
PREVIOUS DISCUSSION....
THE TRANSITION BETWEEN PHASES OF THIS INTENSE AND IMPACTFUL
INCOMING SNOWSTORM IS FULLY UNDERWAY. THE INITIAL SFC LOW THAT
DROPPED DOWN FROM THE NRN PLAINS INTO THE UPPER MIDWEST IS ABOUT
TO BE PHASED-OUT. THE NEWER AND STRONGER LOW CURRENTLY OVER THE
RALEIGH NC AREA WILL CREATE A SNOWY AND HAZARDOUS WEDNESDAY FOR
MUCH OF THE MID-ATLC. THE NEXT SEVERAL HOURS WILL BE THE CRITICAL
TRANSITION PERIOD AS THIS LOW INTENSIFIES AND ROTATES DUE NE
TOWARD THE LOWER TIP OF THE DELMARVA PENINSULA AND DEVELOPS HEAVY
SNOW BAND ACROSS THE NWRN QUADRANT OF THE LOW DURING THE DAYTIME
HRS.
THROUGH DAYBREAK...
A REGIONAL VIEW OF THE RADAR RETURNS SHOWS THAT SNOW STILL AFFECTING
MUCH OF THE UPPER MIDWEST...FROM CNTRL IN TO THE APLCNS...BUT THIS
AREA OF PRECIP REGION WILL DISSIPATE IN THE NEXT FEW HRS. ONLY
POCKETS OF HIGHER ELEVATION UPSLOPE SNOW WILL CONTINUE ALONG THE
APLCN CHAIN.
THE FIRST PHASE OF THE SYSTEM THAT BROUGHT LIGHT TO MODERATE SNOW
OVER THE ENTIRE REGION IN JUST THE PAST FEW HOURS IS JUST THE START.
ABOUT A HALF-FOOT OF SNOW HAS ALREADY FALLEN OVER THE HIGHER TERRAIN
OF THE CNTRL APLCNS...TOWARD THE BLUE RIDGE. A FEW INCHES HAVE
BEEN COMMON OVER THE SWRN QUADRANT OF THE CWA THRU 2-3AM. THE
HEAVIER BANDS THAT BROUGHT THIS ACTIVITY ARE NOW SPREADING ACROSS
THE DC/BALT AND THE PIEDMONT AREAS. THIS ACTIVITY WILL CREATE THE
FIRST LAYER OF SNOW AND ALLOW FOR THE INITIAL BASE FOR ACCUMULATIONS
FROM THE SECOND PHASE OF THE STORM.
WINDS HAVE BEEN INTERMITTENTLY INCREASED...NORMALLY W/ SOME OF THE
HEAVIER BANDS BUT THEN DROP BACK DOWN TO 5-10MPH. THESE LOWER WIND
SPEEDS ARE ALLOWING FOR THE RELATIVELY HIGHER VISIBILITIES IN THE
1-2SM RANGE. THIS WILL CHANGE AS WINDS INCREASE AND SNOW
INTENSITIES INCREASE. DETERMINISTIC NAM AND GFS RUNS STILL BULLISH
ON QPF...SO THE CURRENT FORECAST IS A GOOD MIX OF NEAR TERM HI-RES
GUIDANCE...INCLUDING LOCAL VERSION OF THE VARIOUS WRF MEMBERS AND
ESPC THE HRRR WHICH HAS DONE WELL W/ INITIALIZING OVER THE FIRST
PART OF THIS EVENT.
DAYBREAK THROUGH MIDDAY...
IF THEY HAVEN`T ALREADY BY DAYBREAK - CONDITIONS WILL DETERIORATE
RAPIDLY ACROSS MOST - IF NOT ALL - OF THE CWA. LOCALIZED AREAS WILL
RECEIVE BRIEF INTENSE SNOWFALL RATES OF 1-2 INCHES PER HR...POSSIBLY
HIGHER. NOW THAT THE LOW IS ON THE DOORSTEP AND NEAR-TERM GUIDANCE
HAS BEEN INITIALIZING W/ THIS DATA...SOME OF THE HI-RES MEMBERS HAVE
STARTED TO DEPICT ONE LARGE ENCOMPASSING SNOW BAND - ORIENTED ALONG
THE I-95 CORRIDOR BUT STRETCHING OVER THE ENTIRETY OF THE
PIEDMONT/COASTAL COUNTIES...TAPERING OFF TOWARD THE BLUE RIDGE AND
APLCNS. WITHIN THIS LARGER BAND WILL BE THE DYNAMIC HEAVIER BANDS W/
THE HIGHER INTENSITIES AND LOW VISIBILITIES.
WINDS AROUND THIS SECTOR OF THE STORM WILL BE STRENGTHENING W/ SUST
SPEEDS IN THE 15-25MPH RANGE AND PEAK GUSTS IN THE 30-40MPH RANGE.
NEAR-WHITEOUT CONDITIONS ARE STILL IN QUESTION...IN TERMS OF AREA
AND DURATION. THERE WILL BE BRIEF PERIODS OF NEAR-WHITEOUT
CONDITIONS BUT AS FAR WIDESPREAD AND LONG-LIVED DURATIONS...
CONFIDENCE IS LOWER. REGARDLESS...THE HEAVY-WET SNOW AND GUSTY WINDS
WILL CREATE DANGEROUS AND NEAR-IMPOSSIBLE TRAVEL AT TIMES.
MIDDAY THROUGH LATE TONIGHT...
THE HEIGHT OF SNOWFALL RATES AND INTENSITIES ACROSS THE I-95
CORRIDOR...THE METRO AREAS AND THE VA/MD PIEDMONT IS EXPECTED TO BE
FROM THE LATE MRNG INTO THE EARLY AFTN HRS. AT THIS TIME...THE LOW
WILL BE MOVING AWAY FROM THE OCEAN CITY MD AREA...PULLING AWAY FROM
THE COAST AND STARTING TO TAKE THE PRECIP ALONG WITH IT.
SEVERAL ADDITIONAL INCHES OF SNOW WILL ACCUMULATE ACROSS THE
REGION...BRINGING TOTALS TO LIKELY OVER A FOOT ACROSS MUCH OF THE
SHEN VLY AND BETWEEN ONE-TO-TWO FT ALONG THE SURROUNDING
RIDGELINES...JUST UNDER A FOOT ACROSS THE VA PIEDMONT AND JUST INTO
N CNTRL MD...MORE OF A 6-12 INCH SPREAD ALONG THE I-95 CORRIDOR AND
A RAIN/SNOW MIX ALONG THE WRN BAYSHORE COUNTIES AND SRN MD - THOUGH
4-8 INCH TOTAL STILL POSSIBLE AT THE TAIL END OF STORM SYSTEM
LATER IN THE AFTN/EVE.
A RAPID DECREASE IN SNOW INTENSITIES WILL OCCUR TOWARD THE
MIDDLE/LATE EVE HRS FROM WEST-TO-EAST AS THE LOW ACCELERATES OFF THE
COAST AND DISSIPATES THE LARGER SNOW BAND OVER THE REGION. ONLY
FLURRIES AND RESIDUAL LIGHT POCKETS OF SNOW CONTINUE LATE THIS EVE
BUT ALSO DISSIPATE INTO THE OVERNIGHT HRS. AS CONDITIONS DRY
OUT...WINDS WILL REMAIN. TEMPS WON`T DROP TOO MUCH FURTHER BELOW
FREEZING BUT WILL CHILLS WILL...AS A DRIER BITING NW WIND TAKES OVER
INTO THE EARLY MRNG HRS THU.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY/...
COASTAL LOW WILL BE WELL OFFSHORE THURSDAY MORNING...BUT IS FORECAST
TO MOVE LITTLE AND MEANDER ACROSS THE WESTERN ATLANTIC THROUGH
FRIDAY. THIS WILL KEEP THE CWA IN A NORTHERLY FLOW DURING THIS TIME.
ANY LINGERING SNOWFALL ASSOCIATED WITH WRAP AROUND/DEFORMATION
SHOULD MOVE EAST OF THE BAY THURSDAY MORNING...LEAVING A DRY
FORECAST FOR THE REST OF THE DAY SAVE FOR SOME SNOW SHOWERS ON THE
WESTERN SLOPES. IN FACT...PARTIAL SUNSHINE MAY EVEN BE SEEN IN THE
AFTERNOON WHICH WILL HELP TO MELT SOME SNOW. BUT WITH
SNOWPACK...OPTED REMAIN BELOW MOS GUIDANCE FOR MAXIMA. KEPT THE
SAME IDEA FOR MINIMA THURSDAY NIGHT...ESPECIALLY WITH MODELS
SHOWING CLEAR TO PARTLY CLOUDY SKIES.
NAM IS MORE AGGRESSIVE TRYING TO WRAP AROUND MORE CLOUDS AND EVEN
SOME PRECIP ACROSS THE NORTHEAST PORTION OF THE CWA FRIDAY.
CONFIDENCE IS LOW ON PRECIP BEING ABLE TO WRAP BACK THIS FAR WEST
SO KEPT DRY FORECAST...BUT DID INCLUDE MORE CLOUDS.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
THE LOW WILL GRADUALLY PULL AWAY FROM THE AREA THIS WEEKEND AS SFC
HIPRES/UPPER RIDGE BUILDS ACROSS THE ERN CONUS. A MODERATING TREND
CAN BE EXPECTED THROUGH ERY NEXT WEEK. MAX TEMPS WILL BE IN 40S
WHERE A DEEPER SNOW PACK PERSISTS AND POSSIBLY 50S FARTHER EAST NEAR
I-95.
EXTENDED-RANGE GUIDANCE HAS TRENDED SLOWER WITH THE NEXT LOPRES
SYSTEM AND COLD FRONT...WHICH NOW LOOKS TO APPROACH LATE MON OR TUE.
GIVEN LATEST TRACK OF SFC LOW...DEEP WARM SLY FLOW IN PRE-FRONTAL
WARM SECTOR MAY LEAD TO SIGNIFICANT MELTING OF SNOW PACK AS HIGHS
COULD POTENTIALLY REACH THE UPPER 40S AND 50S MON/TUE.
&&
.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
A SNOWSTORM FOR MUCH OF THE AREA TODAY. THE PAST SEVERAL HRS HAS
BEEN THE WARM-UP FOR THE MORE INTENSE VERSION LATER THIS MRNG AND
AFTN. SOLID IFR CONDS ALREADY COVERING THE REGION W/ A FEW LIFR OBS
SCATTERED ABOUT...UNDER THE HEAVIER SNOW BANDS. THE RESPONSIBLE SFC
LOW IS STILL OVER ERN NC BUT WILL MOVE TOWARD THE NORFOLK VA AREA IN
THE COMING HRS...INTENSIFY AND CREATE A STRONGER LOW LEVEL WIND
FIELD BACK ACROSS MD/NRN VA. INTENSE SNOWFALL RATES...GUSTY WINDS
AND REDUCED VSBYS WILL BE CENTERED OVER THE I-95 CORRIDOR AND BACK
TOWARD THE BLUE RIDGE BETWEEN THROUGH 20Z...TAPERING OFF TOWARD
THE END OF THAT PERIOD. SNOW WILL BEGIN TO DISSIPATE DURING THE
EVE HRS...BUT WINDS WILL REMAIN BREEZY OUT OF THE NW ALL NIGHT AND
INTO THU.
PRECIP SHOULD SHUT OFF BY EARLY THURSDAY MORNING...WITH A RETURN
TO VFR CONDITIONS FOR THURSDAY. MAIN IMPACT WILL BE FROM GUSTY
NORTHWEST WINDS WHICH MAY LINGER INTO FRIDAY. QUIET WITH HIGH
PRESSURE THIS WEEKEND.
&&
.MARINE...
GALE FORCE WIND GUSTS WILL BECOME MORE COMMON HEADING INTO THE MRNG
HRS TODAY...AS A SFC LOW MOVES FROM NRN NC TOWARD THE DELMARVA
REGION. BREEZY E-NELY WINDS WILL BECOME INTENSE NLY WINDS WHILE THE
LOW IS MOVING OFF THE COAST LATER THIS MRNG. SOLID GALE GUSTS WILL
STREAM DOWN THE MAIN CHANNEL OF THE BAY AND TP RVR. THIS WILL
CONTINUE INTO THE LATE NIGHT HRS...AND WINDS WILL STILL GUST IN THE
GALE RANGE OVERNIGHT.
WINDS BECOME NORTHWEST BY THURSDAY...AND WITH FORECAST GRADIENT
HAVE EXTEND GALES FOR MUCH OF THE MARINE AREA INTO THURSDAY. SCA
CONDITIONS ARE LIKELY TO LINGER THROUGH THE END OF THE WEEK.
&&
.HYDROLOGY...
MODEL GUIDANCE REMAINS REMARKABLY CONSISTENT WITH A QPF BULLSEYE IN
THE RAPPAHANNOCK BASIN. AROUND TWO INCHES OF LIQUID/LIQUID EQUIV
PRECIPITATION IS LIKELY THROUGH MUCH OF THAT BASIN. IT LOOKS LIKE
THE MAJORITY OF THAT WILL WIND UP BEING FROM SNOW ESPECIALLY IN
THE UPPER PART. IN ADDITION...SFC TEMPS AND SOIL TEMPS ARE AND
WILL REMAIN ABOVE FREEZING OUTSIDE THE HIGHER ELEVATIONS...SO
THERE WILL BE SOME SOIL INFILTRATION INITIALLY FROM RAIN...LIQUID
FROM SNOW...OR BOTH. THEN WE HAVE TO LOOK AT HOW QUICKLY THE SNOW
MELTS...AND HOW LONG IT TAKES TO START MELTING THE MOUNTAIN SNOWS
TO ADD TO THE PICTURE. THE MOST LIKELY SCENARIO IS FOR THERE TO BE
A GRADUAL MELT...WHICH WOULD NOT POSE MUCH OF A FLOOD THREAT...BUT
THE AFOREMENTIONED UNCERTAINTIES LEND THEMSELVES TO KEEPING AN EYE
ON THE SITUATION THROUGH THE END OF THE WEEK.
&&
.TIDES/COASTAL FLOODING...
ANOMALIES HAVE TURNED POSITIVE...CLOSE TO 1 FT ABOVE NORMAL AT 3 AM
ALONG THE WESTERN SHORE OF THE BAY. WITH EASTERLY FLOW PERSISTING
THIS MORNING...ANOMALIES WILL CONTINUE TO CLIMB POSSIBLY ON THE
ORDER OF 1.5 TO 2 FT ABOVE NORMAL. THIS WILL PRODUCE MINOR TIDAL
FLOODING ALONG THE WESTERN SHORE OF THE CHESAPEAKE BAY UP THROUGH AT
LEAST ANNE ARUNDEL COUNTY...AND CONFIDENCE IS INCREASING OF THE
MINOR THRESHOLD BEING REACHED TOWARD BALTIMORE DURING HIGH TIDE.
CONFIDENCE DECREASES NORTH OF HERE WITH AN EAST WIND BECOMING
NORTHEAST BY HIGH TIDE TIME. SAME GOES FOR THE UPPER TIDAL
POTOMAC...SO WILL REFRAIN FROM ADVISORY IN THESE AREAS DO TO LOWER
CONFIDENCE BUT WILL NEED TO BE WATCHED.
LATER THIS AFTERNOON AND EVENING WHEN WINDS DO TURN
NORTHERLY...THERE WILL BE A SHARP BLOWOUT TIDE...PERHAPS
COMPLETELY DAMPENING OUT THE WEDNESDAY NIGHT HIGH TIDE ALTOGETHER
IN THE UPPER BAY. FORECAST MODEL SHOWS A LITTLE WATER TRAPPING IN
THE LOWERMOST TIDAL POTOMAC THAT KEEPS LEVELS ELEVATED FOR THE
WEDNESDAY EVENING CYCLE THERE. WILL HAVE TO KEEP AN EYE ON THAT.
WINDS TURN OUT OF THE NORTHWEST AFTER THAT...WHICH SHOULD MAKE
EVERYTHING DROP SIGNIFICANTLY.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...WINTER STORM WARNING UNTIL 3 AM EST THURSDAY FOR DCZ001.
MD...WINTER STORM WARNING UNTIL MIDNIGHT EST TONIGHT FOR MDZ003-501-
502.
WINTER STORM WARNING UNTIL 3 AM EST THURSDAY FOR MDZ004>007-
009>011-013-014-016>018.
COASTAL FLOOD ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR
MDZ014-017-018.
COASTAL FLOOD ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
MDZ011.
VA...WINTER STORM WARNING UNTIL MIDNIGHT EST TONIGHT FOR VAZ025>031-
503-504.
WINTER STORM WARNING UNTIL 3 AM EST THURSDAY FOR VAZ036>040-
042-050>057-501-502.
WV...WINTER STORM WARNING UNTIL MIDNIGHT EST TONIGHT FOR WVZ050>053-
055-501>506.
MARINE...GALE WARNING UNTIL 6 PM EST THURSDAY FOR ANZ530>534-537>543.
SMALL CRAFT ADVISORY FROM 6 AM TO 6 PM EST THURSDAY FOR ANZ535-
536.
GALE WARNING UNTIL 6 AM EST THURSDAY FOR ANZ535-536.
&&
$$
SYNOPSIS...BPP/GMS
NEAR TERM...GMS/KCS
SHORT TERM...BPP
LONG TERM...JRK
AVIATION...JRK/BPP/GMS
MARINE...JRK/BPP/GMS
HYDROLOGY...
TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
400 AM EST WED MAR 6 2013
.SYNOPSIS...
STRONG LOW PRESSURE WILL IMPACT THE AREA THROUGH TONIGHT. THE LOW
WILL MOVE AWAY FROM THE AREA THURSDAY. HIGH PRESSURE WILL BUILD
OVERHEAD LATE IN THE WEEK AND PERSIST THROUGH THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
THE TRANSITION BETWEEN PHASES OF THIS INTENSE AND IMPACTFUL INCOMING
SNOWSTORM IS FULLY UNDERWAY. THE INITIAL SFC LOW THAT DROPPED DOWN
FROM THE NRN PLAINS INTO THE UPPER MIDWEST IS ABOUT TO BE
PHASED-OUT. THE NEWER AND STRONGER LOW CURRENTLY OVER THE RALEIGH NC
AREA WILL CREATE A SNOWY AND HAZARDOUS WEDNESDAY FOR MUCH OF THE
MID-ATLC. THE NEXT SEVERAL HOURS WILL BE THE CRITICAL TRANSITION
PERIOD AS THIS LOW INTENSIFIES AND ROTATES DUE NE TOWARD THE LOWER
TIP OF THE DELMARVA PENINSULA AND DEVELOPS HEAVY SNOW BAND ACROSS
THE NWRN QUADRANT OF THE LOW DURING THE DAYTIME HRS.
THROUGH DAYBREAK...
A REGIONAL VIEW OF THE RADAR RETURNS SHOWS THAT SNOW STILL AFFECTING
MUCH OF THE UPPER MIDWEST...FROM CNTRL IN TO THE APLCNS...BUT THIS
AREA OF PRECIP REGION WILL DISSIPATE IN THE NEXT FEW HRS. ONLY
POCKETS OF HIGHER ELEVATION UPSLOPE SNOW WILL CONTINUE ALONG THE
APLCN CHAIN.
THE FIRST PHASE OF THE SYSTEM THAT BROUGHT LIGHT TO MODERATE SNOW
OVER THE ENTIRE REGION IN JUST THE PAST FEW HOURS IS JUST THE START.
ABOUT A HALF-FOOT OF SNOW HAS ALREADY FALLEN OVER THE HIGHER TERRAIN
OF THE CNTRL APLCNS...TOWARD THE BLUE RIDGE. A FEW INCHES HAVE
BEEN COMMON OVER THE SWRN QUADRANT OF THE CWA THRU 2-3AM. THE
HEAVIER BANDS THAT BROUGHT THIS ACTIVITY ARE NOW SPREADING ACROSS
THE DC/BALT AND THE PIEDMONT AREAS. THIS ACTIVITY WILL CREATE THE
FIRST LAYER OF SNOW AND ALLOW FOR THE INITIAL BASE FOR ACCUMULATIONS
FROM THE SECOND PHASE OF THE STORM.
WINDS HAVE BEEN INTERMITTENTLY INCREASED...NORMALLY W/ SOME OF THE
HEAVIER BANDS BUT THEN DROP BACK DOWN TO 5-10MPH. THESE LOWER WIND
SPEEDS ARE ALLOWING FOR THE RELATIVELY HIGHER VISIBILITIES IN THE
1-2SM RANGE. THIS WILL CHANGE AS WINDS INCREASE AND SNOW
INTENSITIES INCREASE. DETERMINISTIC NAM AND GFS RUNS STILL BULLISH
ON QPF...SO THE CURRENT FORECAST IS A GOOD MIX OF NEAR TERM HI-RES
GUIDANCE...INCLUDING LOCAL VERSION OF THE VARIOUS WRF MEMBERS AND
ESPC THE HRRR WHICH HAS DONE WELL W/ INITIALIZING OVER THE FIRST
PART OF THIS EVENT.
DAYBREAK THROUGH MIDDAY...
IF THEY HAVEN`T ALREADY BY DAYBREAK - CONDITIONS WILL DETERIORATE
RAPIDLY ACROSS MOST - IF NOT ALL - OF THE CWA. LOCALIZED AREAS WILL
RECEIVE BRIEF INTENSE SNOWFALL RATES OF 1-2 INCHES PER HR...POSSIBLY
HIGHER. NOW THAT THE LOW IS ON THE DOORSTEP AND NEAR-TERM GUIDANCE
HAS BEEN INITIALIZING W/ THIS DATA...SOME OF THE HI-RES MEMBERS HAVE
STARTED TO DEPICT ONE LARGE ENCOMPASSING SNOW BAND - ORIENTED ALONG
THE I-95 CORRIDOR BUT STRETCHING OVER THE ENTIRETY OF THE
PIEDMONT/COASTAL COUNTIES...TAPERING OFF TOWARD THE BLUE RIDGE AND
APLCNS. WITHIN THIS LARGER BAND WILL BE THE DYNAMIC HEAVIER BANDS W/
THE HIGHER INTENSITIES AND LOW VISIBILITIES.
WINDS AROUND THIS SECTOR OF THE STORM WILL BE STRENGTHENING W/ SUST
SPEEDS IN THE 15-25MPH RANGE AND PEAK GUSTS IN THE 30-40MPH RANGE.
NEAR-WHITEOUT CONDITIONS ARE STILL IN QUESTION...IN TERMS OF AREA
AND DURATION. THERE WILL BE BRIEF PERIODS OF NEAR-WHITEOUT
CONDITIONS BUT AS FAR WIDESPREAD AND LONG-LIVED DURATIONS...
CONFIDENCE IS LOWER. REGARDLESS...THE HEAVY-WET SNOW AND GUSTY WINDS
WILL CREATE DANGEROUS AND NEAR-IMPOSSIBLE TRAVEL AT TIMES.
MIDDAY THROUGH LATE TONIGHT...
THE HEIGHT OF SNOWFALL RATES AND INTENSITIES ACROSS THE I-95
CORRIDOR...THE METRO AREAS AND THE VA/MD PIEDMONT IS EXPECTED TO BE
FROM THE LATE MRNG INTO THE EARLY AFTN HRS. AT THIS TIME...THE LOW
WILL BE MOVING AWAY FROM THE OCEAN CITY MD AREA...PULLING AWAY FROM
THE COAST AND STARTING TO TAKE THE PRECIP ALONG WITH IT.
SEVERAL ADDITIONAL INCHES OF SNOW WILL ACCUMULATE ACROSS THE
REGION...BRINGING TOTALS TO LIKELY OVER A FOOT ACROSS MUCH OF THE
SHEN VLY AND BETWEEN ONE-TO-TWO FT ALONG THE SURROUNDING
RIDGELINES...JUST UNDER A FOOT ACROSS THE VA PIEDMONT AND JUST INTO
N CNTRL MD...MORE OF A 6-12 INCH SPREAD ALONG THE I-95 CORRIDOR AND
A RAIN/SNOW MIX ALONG THE WRN BAYSHORE COUNTIES AND SRN MD - THOUGH
4-8 INCH TOTAL STILL POSSIBLE AT THE TAIL END OF STORM SYSTEM
LATER IN THE AFTN/EVE.
A RAPID DECREASE IN SNOW INTENSITIES WILL OCCUR TOWARD THE
MIDDLE/LATE EVE HRS FROM WEST-TO-EAST AS THE LOW ACCELERATES OFF THE
COAST AND DISSIPATES THE LARGER SNOW BAND OVER THE REGION. ONLY
FLURRIES AND RESIDUAL LIGHT POCKETS OF SNOW CONTINUE LATE THIS EVE
BUT ALSO DISSIPATE INTO THE OVERNIGHT HRS. AS CONDITIONS DRY
OUT...WINDS WILL REMAIN. TEMPS WON`T DROP TOO MUCH FURTHER BELOW
FREEZING BUT WILL CHILLS WILL...AS A DRIER BITING NW WIND TAKES OVER
INTO THE EARLY MRNG HRS THU.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY/...
COASTAL LOW WILL BE WELL OFFSHORE THURSDAY MORNING...BUT IS FORECAST
TO MOVE LITTLE AND MEANDER ACROSS THE WESTERN ATLANTIC THROUGH
FRIDAY. THIS WILL KEEP THE CWA IN A NORTHERLY FLOW DURING THIS TIME.
ANY LINGERING SNOWFALL ASSOCIATED WITH WRAP AROUND/DEFORMATION
SHOULD MOVE EAST OF THE BAY THURSDAY MORNING...LEAVING A DRY
FORECAST FOR THE REST OF THE DAY SAVE FOR SOME SNOW SHOWERS ON THE
WESTERN SLOPES. IN FACT...PARTIAL SUNSHINE MAY EVEN BE SEEN IN THE
AFTERNOON WHICH WILL HELP TO MELT SOME SNOW. BUT WITH
SNOWPACK...OPTED REMAIN BELOW MOS GUIDANCE FOR MAXIMA. KEPT THE
SAME IDEA FOR MINIMA THURSDAY NIGHT...ESPECIALLY WITH MODELS
SHOWING CLEAR TO PARTLY CLOUDY SKIES.
NAM IS MORE AGGRESSIVE TRYING TO WRAP AROUND MORE CLOUDS AND EVEN
SOME PRECIP ACROSS THE NORTHEAST PORTION OF THE CWA FRIDAY.
CONFIDENCE IS LOW ON PRECIP BEING ABLE TO WRAP BACK THIS FAR WEST
SO KEPT DRY FORECAST...BUT DID INCLUDE MORE CLOUDS.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
THE LOW WILL GRADUALLY PULL AWAY FROM THE AREA THIS WEEKEND AS SFC
HIPRES/UPPER RIDGE BUILDS ACROSS THE ERN CONUS. A MODERATING TREND
CAN BE EXPECTED THROUGH ERY NEXT WEEK. MAX TEMPS WILL BE IN 40S
WHERE A DEEPER SNOW PACK PERSISTS AND POSSIBLY 50S FARTHER EAST NEAR
I-95.
EXTENDED-RANGE GUIDANCE HAS TRENDED SLOWER WITH THE NEXT LOPRES
SYSTEM AND COLD FRONT...WHICH NOW LOOKS TO APPROACH LATE MON OR TUE.
GIVEN LATEST TRACK OF SFC LOW...DEEP WARM SLY FLOW IN PRE-FRONTAL
WARM SECTOR MAY LEAD TO SIGNIFICANT MELTING OF SNOW PACK AS HIGHS
COULD POTENTIALLY REACH THE UPPER 40S AND 50S MON/TUE.
&&
.AVIATION /08Z WEDNESDAY THROUGH SUNDAY/...
A SNOWSTORM FOR MUCH OF THE AREA TODAY. THE PAST SEVERAL HRS HAS
BEEN THE WARM-UP FOR THE MORE INTENSE VERSION LATER THIS MRNG AND
AFTN. SOLID IFR CONDS ALREADY COVERING THE REGION W/ A FEW LIFR OBS
SCATTERED ABOUT...UNDER THE HEAVIER SNOW BANDS. THE RESPONSIBLE SFC
LOW IS STILL OVER ERN NC BUT WILL MOVE TOWARD THE NORFOLK VA AREA IN
THE COMING HRS...INTENSIFY AND CREATE A STRONGER LOW LEVEL WIND
FIELD BACK ACROSS MD/NRN VA. INTENSE SNOWFALL RATES...GUSTY WINDS
AND REDUCED VSBYS WILL BE CENTERED OVER THE I-95 CORRIDOR AND BACK
TOWARD THE BLUE RIDGE BETWEEN THROUGH 20Z...TAPERING OFF TOWARD
THE END OF THAT PERIOD. SNOW WILL BEGIN TO DISSIPATE DURING THE
EVE HRS...BUT WINDS WILL REMAIN BREEZY OUT OF THE NW ALL NIGHT AND
INTO THU.
PRECIP SHOULD SHUT OFF BY EARLY THURSDAY MORNING...WITH A RETURN
TO VFR CONDITIONS FOR THURSDAY. MAIN IMPACT WILL BE FROM GUSTY
NORTHWEST WINDS WHICH MAY LINGER INTO FRIDAY. QUIET WITH HIGH
PRESSURE THIS WEEKEND.
&&
.MARINE...
GALE FORCE WIND GUSTS WILL BECOME MORE COMMON HEADING INTO THE MRNG
HRS TODAY...AS A SFC LOW MOVES FROM NRN NC TOWARD THE DELMARVA
REGION. BREEZY E-NELY WINDS WILL BECOME INTENSE NLY WINDS WHILE THE
LOW IS MOVING OFF THE COAST LATER THIS MRNG. SOLID GALE GUSTS WILL
STREAM DOWN THE MAIN CHANNEL OF THE BAY AND TP RVR. THIS WILL
CONTINUE INTO THE LATE NIGHT HRS...AND WINDS WILL STILL GUST IN THE
GALE RANGE OVERNIGHT.
WINDS BECOME NORTHWEST BY THURSDAY...AND WITH FORECAST GRADIENT
HAVE EXTEND GALES FOR MUCH OF THE MARINE AREA INTO THURSDAY. SCA
CONDITIONS ARE LIKELY TO LINGER THROUGH THE END OF THE WEEK.
&&
.HYDROLOGY...
MODEL GUIDANCE REMAINS REMARKABLY CONSISTENT WITH A QPF BULLSEYE IN
THE RAPPAHANNOCK BASIN. AROUND TWO INCHES OF LIQUID/LIQUID EQUIV
PRECIPITATION IS LIKELY THROUGH MUCH OF THAT BASIN. IT LOOKS LIKE
THE MAJORITY OF THAT WILL WIND UP BEING FROM SNOW ESPECIALLY IN
THE UPPER PART. IN ADDITION...SFC TEMPS AND SOIL TEMPS ARE AND
WILL REMAIN ABOVE FREEZING OUTSIDE THE HIGHER ELEVATIONS...SO
THERE WILL BE SOME SOIL INFILTRATION INITIALLY FROM RAIN...LIQUID
FROM SNOW...OR BOTH. THEN WE HAVE TO LOOK AT HOW QUICKLY THE SNOW
MELTS...AND HOW LONG IT TAKES TO START MELTING THE MOUNTAIN SNOWS
TO ADD TO THE PICTURE. THE MOST LIKELY SCENARIO IS FOR THERE TO BE
A GRADUAL MELT...WHICH WOULD NOT POSE MUCH OF A FLOOD THREAT...BUT
THE AFOREMENTIONED UNCERTAINTIES LEND THEMSELVES TO KEEPING AN EYE
ON THE SITUATION THROUGH THE END OF THE WEEK.
&&
.TIDES/COASTAL FLOODING...
ANOMALIES HAVE TURNED POSITIVE...CLOSE TO 1 FT ABOVE NORMAL AT 3 AM
ALONG THE WESTERN SHORE OF THE BAY. WITH EASTERLY FLOW PERSISTING
THIS MORNING...ANOMALIES WILL CONTINUE TO CLIMB POSSIBLY ON THE
ORDER OF 1.5 TO 2 FT ABOVE NORMAL. THIS WILL PRODUCE MINOR TIDAL
FLOODING ALONG THE WESTERN SHORE OF THE CHESAPEAKE BAY UP THROUGH AT
LEAST ANNE ARUNDEL COUNTY...AND CONFIDENCE IS INCREASING OF THE
MINOR THRESHOLD BEING REACHED TOWARD BALTIMORE DURING HIGH TIDE.
CONFIDENCE DECREASES NORTH OF HERE WITH AN EAST WIND BECOMING
NORTHEAST BY HIGH TIDE TIME. SAME GOES FOR THE UPPER TIDAL
POTOMAC...SO WILL REFRAIN FROM ADVISORY IN THESE AREAS DO TO LOWER
CONFIDENCE BUT WILL NEED TO BE WATCHED.
LATER THIS AFTERNOON AND EVENING WHEN WINDS DO TURN
NORTHERLY...THERE WILL BE A SHARP BLOWOUT TIDE...PERHAPS
COMPLETELY DAMPENING OUT THE WEDNESDAY NIGHT HIGH TIDE ALTOGETHER
IN THE UPPER BAY. FORECAST MODEL SHOWS A LITTLE WATER TRAPPING IN
THE LOWERMOST TIDAL POTOMAC THAT KEEPS LEVELS ELEVATED FOR THE
WEDNESDAY EVENING CYCLE THERE. WILL HAVE TO KEEP AN EYE ON THAT.
WINDS TURN OUT OF THE NORTHWEST AFTER THAT...WHICH SHOULD MAKE
EVERYTHING DROP SIGNIFICANTLY.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...WINTER STORM WARNING UNTIL 3 AM EST THURSDAY FOR DCZ001.
MD...WINTER STORM WARNING UNTIL MIDNIGHT EST TONIGHT FOR MDZ003-501-
502.
WINTER STORM WARNING UNTIL 3 AM EST THURSDAY FOR MDZ004>007-
009>011-013-014-016>018.
COASTAL FLOOD ADVISORY FROM 7 AM THIS MORNING TO 2 PM EST THIS
AFTERNOON FOR MDZ014-017-018.
COASTAL FLOOD ADVISORY FROM 11 AM THIS MORNING TO 4 PM EST
THIS AFTERNOON FOR MDZ011.
VA...WINTER STORM WARNING UNTIL MIDNIGHT EST TONIGHT FOR VAZ025>031-
503-504.
WINTER STORM WARNING UNTIL 3 AM EST THURSDAY FOR VAZ036>040-
042-050>057-501-502.
WV...WINTER STORM WARNING UNTIL MIDNIGHT EST TONIGHT FOR WVZ050>053-
055-501>506.
MARINE...GALE WARNING UNTIL 6 PM EST THURSDAY FOR ANZ530>534-537>543.
SMALL CRAFT ADVISORY FROM 6 AM TO 6 PM EST THURSDAY FOR ANZ535-
536.
GALE WARNING UNTIL 6 AM EST THURSDAY FOR ANZ535-536.
&&
$$
SYNOPSIS...BPP/GMS
NEAR TERM...GMS
SHORT TERM...BPP
LONG TERM...JRK
AVIATION...JRK/BPP/GMS
MARINE...JRK/BPP/GMS
HYDROLOGY...BPP/JE
TIDES/COASTAL FLOODING...BPP/JE
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1242 PM EST WED MAR 6 2013
.UPDATE...
ISSUED AT 1151 AM EST WED MAR 6 2013
ONLY MINOR ADJUSTMENTS TO THE GOING FORECAST...MOST OF WHICH WERE
DONE EARLIER TO EXPAND THE SOUTHERN EXTENT OF THE SNOWFALL TO SHOW
A PERIOD OF SNOW MOVING EAST THROUGH THE AREA. THIS SNOW IS
ASSOCIATED WITH THE SHORTWAVE SEEN ON WV IMAGERY MOVING ACROSS
WESTERN LAKE SUPERIOR AND INTO WESTERN UPPER MICHIGAN AND AN
AREA OF MID LEVEL FGEN AND Q-VECTOR CONVERGENCE. OVER THE
LAST HOUR OR TWO...THE SNOW HAS INCREASED IN INTENSITY ON RADAR AND
WE HAVE SEEN 1.1 INCHES THUS FAR AT THE OFFICE. THUS...TWEAKED UP
SNOWFALL AMOUNTS OVER THE NORTH HALF OF THE EASTERN CWA TO AN
ADDITIONAL INCH THROUGH THE AFTERNOON.
DRY AIR SURGING IN BEHIND THE SHORTWAVE HAS BROUGHT AN END TO THE
SYNOPTIC SNOW OUT WEST AND VISIBLE SATELLITE SHOWS THAT LAKE EFFECT
SNOW BANDS HAVE DEVELOPED OVER THE WESTERN LAKE. WILL HOLD ONTO
SCATTERED SNOW SHOWERS OVER THE WEST THROUGH THE AFTERNOON AND HAVE
MADE AN ADJUSTMENT UP TO POPS /TO HIGH END SCATTERED/ OVER THE
KEWEENAW THIS EVENING...AS COLDER AIR ROTATES SOUTHEAST BEHIND THE
SHORTWAVE.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 534 AM EST WED MAR 6 2013
INITIAL CONCERNS THIS MORNING COME FROM WIDESPREAD -FZDZ ACROSS THE
NORTHERN CWA. PROFILE TEMPS AT OR ABOVE -10C ARE ALLOWING FOR PRECIP
TO STAY GENERALLY IN LIQUID FORM. THERE HAVE BEEN REPORTS OF ROADS
BECOMING SLIPPERY...AND A DECENT GLAZE HAS BEEN OBSERVED AT OUR
OFFICE. HAVE INCREASED POPS TO WIDESPREAD -FZDZ EARLY THIS
MORNING...AND ISSUED A SPECIAL WX STATEMENT TO ADVISE CAUTION
THROUGH THE MORNING COMMUTE. -FZDZ SHOULD TURN OVER TO SNOW BY
SUNRISE AS TEMPS ALOFT COOL IN RESPONSE TO THE TROUGH.
TODAY...MAIN FOCUS IS ON SNOW POTENTIAL FOR THE NORTHERN HALF
THROUGHOUT THE DAY. A VERY WELL DEFINED SHORTWAVE TROUGH OVER FAR
WESTERN ONTARIO IS ROTATING AROUND THE BASE OF A LARGE SCALE TROUGH
OVER CENTRAL CANADA. WIDESPREAD LIGHT SNOW IS CURRENTLY MOVING
ACROSS FAR NE MN AND WESTERN LAKE SUPERIOR AHEAD OF THIS TROUGH.
FORCING APPEARS TO BE TIED TO AN ACTIVE REGION OF FRONTOGENESIS
AROUND 600MB.
STRONGEST FORCING ALONG THE FRONTOGENESIS BAND IS PUSHING
NORTHEASTWARD AS THE SHORTWAVE PIVOTS AROUND THE LARGE SCALE TROUGH.
THIS TREND IS QUITE EVIDENT ON WV IMAGERY EARLY THIS MORNING.
MEANWHILE...A FAIRLY DEFINED SHORTWAVE TROUGH THAT WAS OBSERVED ON
WV IMAGERY AND RAP ANALYSIS OVER SOUTHERN MANITOBA EARLY THIS
MORNING IS QUICKLY LOSING ITS DEFINITION. THOUGH MODELS ARE SHOWING
THAT THIS SMALL SHORTWAVE WILL REINFORCE THE DECAYING WAVE OVER
MN...HAVE A FEELING MODELS ARE NOT HANDLING THE SMALL NATURE OF THE
WAVE VERY WELL. THE NAM APPEARS TO BE MOST AGGRESSIVE WITH THIS
SYSTEM...SO WILL LOOK MORE TOWARD THE GFS/RAP FOR SHORT TERM
GUIDANCE.
MAIN PRECIP IS FOLLOWING BEHIND A WEAK SFC TROUGH. WINDS WILL BACK
MORE OUT OF THE NORTHWEST BEHIND THE TROUGH...SO BEST PRECIP CHANCES
WILL FOCUS IN UPSLOPE REGIONS FAVORED BY NW WINDS. OVERALL...HAVE
CUT BACK ON POP/QPF/SNOW AMOUNTS...BUT NOT MUCH AS THE LEFT EXIT OF
A STRENGTHENING 100KT UPPER JET WILL MOVE TROUGH NORTHERN WI. NOT
GREAT ALIGNMENT WITH BEST MID-LEVEL Q-VECTOR CONV OVER AND NORTH OF
LAKE SUPERIOR...BUT ENOUGH TO KEEP SLIGHT CHANCE POPS ALONG THE WI
BORDER.
OVERALL EXPECTATION IS FOR AROUND AN INCH OF SNOW FOR MOST LOCATIONS
ALONG LAKE SUPERIOR...WITH UP TO 2 INCHES FOR THE HIGHER TERRAIN.
ONLY A DUSTING IS EXPECTED FOR THE SOUTHERN CWA.
TONIGHT...MAIN FOCUS TURNS TO LINGERING CLOUD COVER AND HOW IT WILL
AFFECT LOW TEMPS. SUBSIDENCE BEHIND THE SHORTWAVE QUICKLY TAKES HOLD
LATE THIS AFTERNOON ACROSS THE WEST HALF...LEADING TO A SHALLOW
STRATUS DECK. ONLY A COUPLE MODELS ARE MORE AGGRESSIVE WITH KEEPING
CLOUDS AROUND. GIVEN THAT THE MARCH SUN SHOULD BE MORE EFFICIENT IN
SOMEWHAT MIXING OUT LOW STRATUS LATE THIS AFTERNOON...FEELING IS
THAT LOCATIONS AWAY FROM UPSLOPE INFLUENCE IN THE WEST WILL SEE
ENOUGH CLEARING TO ALLOW FOR DECENT COOLING OVERNIGHT. LOWERED TEMPS
A FEW DEGREES ALONG THE BORDER...AND WOULD NOT BE SURPRISED IF LOWS
DROP BELOW ZERO IN A FEW SPOTS WELL INLAND.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 534 AM EST WED MAR 6 2013
HIGH PRESSURE BUILDING OVER THE AREA WILL WEAKEN NRLY WINDS
EVENTUALLY CAUSING THEM TO BECOME VARIABLE OVER THE WEST. WITH THE
STRENGTHENING SUBSIDENCE INVERSION...THE QUESTION FOR THURSDAY WILL
BE IF CLOUDS SCOUR OUT. PER PREV FCST...WILL HOLD ONTO THE CLOUDS
THE LONGEST OVER THE EAST WHERE THE NORTHWEST WINDS WILL BE MOST
PERSISTENT. ELSEWHERE...WENT WITH MORE OF A PARTLY CLOUDY TO MOSTLY
SUNNY SKY AS DIURNAL MIXING SHOULD HELP ERODE CLOUDS.
UPPER RIDGE OVER THE AREA THURSDAY NIGHT INTO FRIDAY WILL MAINTAIN
DRY WEATHER. WITH LIGHT WINDS AND CLEAR SKIES UNDER SFC RIDGE
AXIS...DECIDED TO LOWER MIN TEMPS THU NIGHT INTO THE SINGLE DIGITS
ABV ZERO OVER CENTRAL AND ERN INTERIOR. INCREASING CLOUDS AND ONSET
OF RETURN FLOW SRLY WINDS...WILL KEEP TEMPS MORE IN THE LOW TO MID
TEENS WEST. WARM ADVECTION AHEAD OF SHORTWAVE AND ASSOC JET MAX
MOVING ACROSS THE NRN PLAINS AND SCNTRL CANADA SHOULD RESULT IN
INCREASING MID AND HIGH CLOUDS ON FRIDAY. WITH INCREASING SRLY
FLOW...LOOK FOR TEMPS TO REACH WELL INTO THE 30S OVER WEST
HALF...PERHAPS EVEN REACHING 40F FOR DOWNSLOPING LOCATIONS ALONG
LAKE SUPERIOR. FLOW OFF LAKE MICHIGAN WILL KEEP THE EAST COOLER WITH
HIGHS GENERALLY IN THE LOWER TO MID 30S.
BY SATURDAY...AN UPPER TROUGH AND ASSOC CLOSED LOW WILL BE
PARKED OVER THE SOUTHWEST CONUS AND A NORTHERN STREAM TROUGH WILL BE
MOVING THROUGH MANITOBA/SASKATCHEWAN. THE 00Z GFS AND GEM-NH SEEM TO
INDICATE MORE PHASING OF THESE FEATURES THAN THE 00Z ECMWF BUT EVEN
THE ECMWF SHOWS SOME SHORTWAVE ENERGY EJECTING NE FM TROUGH OVER THE
SOUTHWEST CONUS AND MERGING WITH VIGOROUS NRN STREAM SHORTWAVE
MOVING ACROSS THE UPPER GREAT LAKES. THE NRN STREAM SHORTWAVE WILL
HAVE MORE OF AN IMPACT ON OUR WEATHER AND GIVEN THAT THE BEST
FORCING STAYS GENERALLY NW OF THE FCST AREA ALONG TRACK OF
SHORTWAVE...THE BEST CHC FOR PCPN SHOULD BE OVER THE FAR WRN FCST
AREA. DYNAMICS AND MODEL AVG QPF ARGUE FOR LIKELY POPS WEST ON
SATURDAY TAPERING TO LOW CHC POPS EAST. COULD SEE NEAR ADVISORY
SNOWFALL FOR SOME LOCATIONS OVER WESTERN UPPER MICHIGAN AND HAVE
DECIDED TO MENTION POSSIBLE ACCUMULATING SNOW IN THE HWO. WITH 850MB
TEMPS ABV 0C OVER THE SOUTH CENTRAL HAVE KEPT IN MENTION OF
RAIN/SNOW MIX FOR THESE LOCATIONS. AS FRONTAL BOUNDARY MOVES EAST
...LOOK FOR HIGHER CHC TO LIKELY POPS TO TRANSLATE OVER MAINLY EAST
HALF SAT NIGHT WHILE STEADY PCPN TAPERS OFF OVER THE WEST LATE SAT
NIGHT.
HIGH PRESSURE BUILDS INTO THE UPPER GREAT LAKES FOR SUNDAY INTO
SUNDAY NIGHT PROVIDING FOR DRIER CONDITIONS BEHIND THE FRONT EXCEPT
FOR THE LINGERING LIGHT LES POSSIBLE ALONG LAKE SUPERIOR. MORE
UNCERTAINTY BY MONDAY AS THE GFS SHOWS PHASING OF SRN STREAM
SHORTWAVE WITH NRN STREAM AND DEVELOPING WOUND UP SFC LOW TRACKING
OVER LOWER MI INTO LAKE HURON. THE GFS SOLN WOULD DRAW IN COLDER AIR
IN A STRONGER CYCLONIC NRLY FLOW FOR POSSIBLE LAKE ENHANCED SNOW.
MEANWHILE...THE ECMWF KEEPS THE SRN STREAM WAVE TRACKING FARTHER SE
THROUGH THE OHIO VALLEY WITH LTL TO NO IMPACT ON OUR WEATHER. THE
ECMWF SHOWS HINT OF ANOTHER WEAK CLIPPER SHORTWAVE MOVING OVER AREA
FOR TUESDAY. FOR NOW...UNTIL MODELS COME INTO BETTER AGREEMENT WILL
CONTINUE GOING SLIGHT CHC POPS IN FCST FOR MONDAY INTO TUESDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1241 PM EST WED MAR 6 2013
SHORTWAVE THAT BROUGHT THE SNOW TO ALL THREE TAF SITES THIS MORNING
SHOULD CONTINUE EAST THIS AFTERNOON AND BRING AN END TO THE
MODERATE SNOW AT KSAW WITHIN THE NEXT HOUR OR TWO. FOCUS THEN TURNS
TO LAKE EFFECT SNOW WITH THE NORTHWEST WINDS...ESPECIALLY FOR KCMX.
WITH COLDER AIR MOVING SOUTHEAST THROUGH THIS EVENING...EXPECT
LIGHT LAKE EFFECT TO AFFECT KCMX/KIWD THROUGH THE AFTERNOON WITH
MVFR CEILINGS. AS A POCKET OF COLDER AIR MOVES OVER THE KEWEENAW
THIS EVENING...HAVE TRIED TO SHOW A PERIOD OF STRONGER SNOW SHOWERS
BEFORE DRIER AIR FROM AN APPROACHING HIGH PRESSURE MOVES IN
OVERNIGHT. THIS SHOULD BRING AN END TO THE SNOW TONIGHT AND THEN
EVENTUALLY DIMINISH THE CLOUDS TOMORROW MORNING/AFTERNOON.
AT KSAW...HELD ONTO THE MVFR CEILINGS THROUGH MUCH OF THE
NIGHT...BUT THERE IS THE POTENTIAL THEY COULD SCATTER OUT OR GO TO
VFR WITH THE LIGHT DOWNSLOPING NORTHWEST FLOW. DEFINITELY FOLLOWED
THAT TREND FOR TOMORROW MORNING...ALTHOUGH THERE COULD BE DIURNAL CU
REDEVELOPING TOWARDS THE END OF THE TAF PERIOD.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 534 AM EST WED MAR 6 2013
A WEAK TROUGH WILL PASS ACROSS LAKE SUPERIOR TODAY AND BRING NW
WINDS OF 15 TO 25 KNOTS TO THE EASTERN HALF OF LAKE SUPERIOR LATE
THIS AFTERNOON THROUGH TONIGHT. A SURFACE RIDGE WILL THEN MOVE
ACROSS THE AREA THURSDAY INTO FRIDAY AND BRING WINDS UNDER 15 KNOTS.
EXPECT SOUTH WINDS TO INCREASE TO 15 TO 25 KNOTS BY FRIDAY AFTERNOON
FOR CENTRAL AND EASTERN LAKE SUPERIOR. LIGHT WINDS WILL PREVAIL
AGAIN SATURDAY INTO SUNDAY BEFORE A COLD FRONT CROSSES LAKE SUPERIOR
AND USHERS IN NW WINDS OF 15 TO 25 KNOTS OVER THE ENTIRE LAKE SUNDAY
AFTERNOON AND EVENING.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...SRF
SHORT TERM...TK
LONG TERM...VOSS
AVIATION...SRF
MARINE...TK
AREA FORECAST DISCUSSION...UPDATED
NWS MARQUETTE MI
1152 AM EST WED MAR 6 2013
.UPDATE...
ISSUED AT 1151 AM EST WED MAR 6 2013
ONLY MINOR ADJUSTMENTS TO THE GOING FORECAST...MOST OF WHICH WERE
DONE EARLIER TO EXPAND THE SOUTHERN EXTENT OF THE SNOWFALL TO SHOW
A PERIOD OF SNOW MOVING EAST THROUGH THE AREA. THIS SNOW IS
ASSOCIATED WITH THE SHORTWAVE SEEN ON WV IMAGERY MOVING ACROSS
WESTERN LAKE SUPERIOR AND INTO WESTERN UPPER MICHIGAN AND AN
AREA OF MID LEVEL FGEN AND Q-VECTOR CONVERGENCE. OVER THE
LAST HOUR OR TWO...THE SNOW HAS INCREASED IN INTENSITY ON RADAR AND
WE HAVE SEEN 1.1 INCHES THUS FAR AT THE OFFICE. THUS...TWEAKED UP
SNOWFALL AMOUNTS OVER THE NORTH HALF OF THE EASTERN CWA TO AN
ADDITIONAL INCH THROUGH THE AFTERNOON.
DRY AIR SURGING IN BEHIND THE SHORTWAVE HAS BROUGHT AN END TO THE
SYNOPTIC SNOW OUT WEST AND VISIBLE SATELLITE SHOWS THAT LAKE EFFECT
SNOW BANDS HAVE DEVELOPED OVER THE WESTERN LAKE. WILL HOLD ONTO
SCATTERED SNOW SHOWERS OVER THE WEST THROUGH THE AFTERNOON AND HAVE
MADE AN ADJUSTMENT UP TO POPS /TO HIGH END SCATTERED/ OVER THE
KEWEENAW THIS EVENING...AS COLDER AIR ROTATES SOUTHEAST BEHIND THE
SHORTWAVE.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 534 AM EST WED MAR 6 2013
INITIAL CONCERNS THIS MORNING COME FROM WIDESPREAD -FZDZ ACROSS THE
NORTHERN CWA. PROFILE TEMPS AT OR ABOVE -10C ARE ALLOWING FOR PRECIP
TO STAY GENERALLY IN LIQUID FORM. THERE HAVE BEEN REPORTS OF ROADS
BECOMING SLIPPERY...AND A DECENT GLAZE HAS BEEN OBSERVED AT OUR
OFFICE. HAVE INCREASED POPS TO WIDESPREAD -FZDZ EARLY THIS
MORNING...AND ISSUED A SPECIAL WX STATEMENT TO ADVISE CAUTION
THROUGH THE MORNING COMMUTE. -FZDZ SHOULD TURN OVER TO SNOW BY
SUNRISE AS TEMPS ALOFT COOL IN RESPONSE TO THE TROUGH.
TODAY...MAIN FOCUS IS ON SNOW POTENTIAL FOR THE NORTHERN HALF
THROUGHOUT THE DAY. A VERY WELL DEFINED SHORTWAVE TROUGH OVER FAR
WESTERN ONTARIO IS ROTATING AROUND THE BASE OF A LARGE SCALE TROUGH
OVER CENTRAL CANADA. WIDESPREAD LIGHT SNOW IS CURRENTLY MOVING
ACROSS FAR NE MN AND WESTERN LAKE SUPERIOR AHEAD OF THIS TROUGH.
FORCING APPEARS TO BE TIED TO AN ACTIVE REGION OF FRONTOGENESIS
AROUND 600MB.
STRONGEST FORCING ALONG THE FRONTOGENESIS BAND IS PUSHING
NORTHEASTWARD AS THE SHORTWAVE PIVOTS AROUND THE LARGE SCALE TROUGH.
THIS TREND IS QUITE EVIDENT ON WV IMAGERY EARLY THIS MORNING.
MEANWHILE...A FAIRLY DEFINED SHORTWAVE TROUGH THAT WAS OBSERVED ON
WV IMAGERY AND RAP ANALYSIS OVER SOUTHERN MANITOBA EARLY THIS
MORNING IS QUICKLY LOSING ITS DEFINITION. THOUGH MODELS ARE SHOWING
THAT THIS SMALL SHORTWAVE WILL REINFORCE THE DECAYING WAVE OVER
MN...HAVE A FEELING MODELS ARE NOT HANDLING THE SMALL NATURE OF THE
WAVE VERY WELL. THE NAM APPEARS TO BE MOST AGGRESSIVE WITH THIS
SYSTEM...SO WILL LOOK MORE TOWARD THE GFS/RAP FOR SHORT TERM
GUIDANCE.
MAIN PRECIP IS FOLLOWING BEHIND A WEAK SFC TROUGH. WINDS WILL BACK
MORE OUT OF THE NORTHWEST BEHIND THE TROUGH...SO BEST PRECIP CHANCES
WILL FOCUS IN UPSLOPE REGIONS FAVORED BY NW WINDS. OVERALL...HAVE
CUT BACK ON POP/QPF/SNOW AMOUNTS...BUT NOT MUCH AS THE LEFT EXIT OF
A STRENGTHENING 100KT UPPER JET WILL MOVE TROUGH NORTHERN WI. NOT
GREAT ALIGNMENT WITH BEST MID-LEVEL Q-VECTOR CONV OVER AND NORTH OF
LAKE SUPERIOR...BUT ENOUGH TO KEEP SLIGHT CHANCE POPS ALONG THE WI
BORDER.
OVERALL EXPECTATION IS FOR AROUND AN INCH OF SNOW FOR MOST LOCATIONS
ALONG LAKE SUPERIOR...WITH UP TO 2 INCHES FOR THE HIGHER TERRAIN.
ONLY A DUSTING IS EXPECTED FOR THE SOUTHERN CWA.
TONIGHT...MAIN FOCUS TURNS TO LINGERING CLOUD COVER AND HOW IT WILL
AFFECT LOW TEMPS. SUBSIDENCE BEHIND THE SHORTWAVE QUICKLY TAKES HOLD
LATE THIS AFTERNOON ACROSS THE WEST HALF...LEADING TO A SHALLOW
STRATUS DECK. ONLY A COUPLE MODELS ARE MORE AGGRESSIVE WITH KEEPING
CLOUDS AROUND. GIVEN THAT THE MARCH SUN SHOULD BE MORE EFFICIENT IN
SOMEWHAT MIXING OUT LOW STRATUS LATE THIS AFTERNOON...FEELING IS
THAT LOCATIONS AWAY FROM UPSLOPE INFLUENCE IN THE WEST WILL SEE
ENOUGH CLEARING TO ALLOW FOR DECENT COOLING OVERNIGHT. LOWERED TEMPS
A FEW DEGREES ALONG THE BORDER...AND WOULD NOT BE SURPRISED IF LOWS
DROP BELOW ZERO IN A FEW SPOTS WELL INLAND.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 534 AM EST WED MAR 6 2013
HIGH PRESSURE BUILDING OVER THE AREA WILL WEAKEN NRLY WINDS
EVENTUALLY CAUSING THEM TO BECOME VARIABLE OVER THE WEST. WITH THE
STRENGTHENING SUBSIDENCE INVERSION...THE QUESTION FOR THURSDAY WILL
BE IF CLOUDS SCOUR OUT. PER PREV FCST...WILL HOLD ONTO THE CLOUDS
THE LONGEST OVER THE EAST WHERE THE NORTHWEST WINDS WILL BE MOST
PERSISTENT. ELSEWHERE...WENT WITH MORE OF A PARTLY CLOUDY TO MOSTLY
SUNNY SKY AS DIURNAL MIXING SHOULD HELP ERODE CLOUDS.
UPPER RIDGE OVER THE AREA THURSDAY NIGHT INTO FRIDAY WILL MAINTAIN
DRY WEATHER. WITH LIGHT WINDS AND CLEAR SKIES UNDER SFC RIDGE
AXIS...DECIDED TO LOWER MIN TEMPS THU NIGHT INTO THE SINGLE DIGITS
ABV ZERO OVER CENTRAL AND ERN INTERIOR. INCREASING CLOUDS AND ONSET
OF RETURN FLOW SRLY WINDS...WILL KEEP TEMPS MORE IN THE LOW TO MID
TEENS WEST. WARM ADVECTION AHEAD OF SHORTWAVE AND ASSOC JET MAX
MOVING ACROSS THE NRN PLAINS AND SCNTRL CANADA SHOULD RESULT IN
INCREASING MID AND HIGH CLOUDS ON FRIDAY. WITH INCREASING SRLY
FLOW...LOOK FOR TEMPS TO REACH WELL INTO THE 30S OVER WEST
HALF...PERHAPS EVEN REACHING 40F FOR DOWNSLOPING LOCATIONS ALONG
LAKE SUPERIOR. FLOW OFF LAKE MICHIGAN WILL KEEP THE EAST COOLER WITH
HIGHS GENERALLY IN THE LOWER TO MID 30S.
BY SATURDAY...AN UPPER TROUGH AND ASSOC CLOSED LOW WILL BE
PARKED OVER THE SOUTHWEST CONUS AND A NORTHERN STREAM TROUGH WILL BE
MOVING THROUGH MANITOBA/SASKATCHEWAN. THE 00Z GFS AND GEM-NH SEEM TO
INDICATE MORE PHASING OF THESE FEATURES THAN THE 00Z ECMWF BUT EVEN
THE ECMWF SHOWS SOME SHORTWAVE ENERGY EJECTING NE FM TROUGH OVER THE
SOUTHWEST CONUS AND MERGING WITH VIGOROUS NRN STREAM SHORTWAVE
MOVING ACROSS THE UPPER GREAT LAKES. THE NRN STREAM SHORTWAVE WILL
HAVE MORE OF AN IMPACT ON OUR WEATHER AND GIVEN THAT THE BEST
FORCING STAYS GENERALLY NW OF THE FCST AREA ALONG TRACK OF
SHORTWAVE...THE BEST CHC FOR PCPN SHOULD BE OVER THE FAR WRN FCST
AREA. DYNAMICS AND MODEL AVG QPF ARGUE FOR LIKELY POPS WEST ON
SATURDAY TAPERING TO LOW CHC POPS EAST. COULD SEE NEAR ADVISORY
SNOWFALL FOR SOME LOCATIONS OVER WESTERN UPPER MICHIGAN AND HAVE
DECIDED TO MENTION POSSIBLE ACCUMULATING SNOW IN THE HWO. WITH 850MB
TEMPS ABV 0C OVER THE SOUTH CENTRAL HAVE KEPT IN MENTION OF
RAIN/SNOW MIX FOR THESE LOCATIONS. AS FRONTAL BOUNDARY MOVES EAST
...LOOK FOR HIGHER CHC TO LIKELY POPS TO TRANSLATE OVER MAINLY EAST
HALF SAT NIGHT WHILE STEADY PCPN TAPERS OFF OVER THE WEST LATE SAT
NIGHT.
HIGH PRESSURE BUILDS INTO THE UPPER GREAT LAKES FOR SUNDAY INTO
SUNDAY NIGHT PROVIDING FOR DRIER CONDITIONS BEHIND THE FRONT EXCEPT
FOR THE LINGERING LIGHT LES POSSIBLE ALONG LAKE SUPERIOR. MORE
UNCERTAINTY BY MONDAY AS THE GFS SHOWS PHASING OF SRN STREAM
SHORTWAVE WITH NRN STREAM AND DEVELOPING WOUND UP SFC LOW TRACKING
OVER LOWER MI INTO LAKE HURON. THE GFS SOLN WOULD DRAW IN COLDER AIR
IN A STRONGER CYCLONIC NRLY FLOW FOR POSSIBLE LAKE ENHANCED SNOW.
MEANWHILE...THE ECMWF KEEPS THE SRN STREAM WAVE TRACKING FARTHER SE
THROUGH THE OHIO VALLEY WITH LTL TO NO IMPACT ON OUR WEATHER. THE
ECMWF SHOWS HINT OF ANOTHER WEAK CLIPPER SHORTWAVE MOVING OVER AREA
FOR TUESDAY. FOR NOW...UNTIL MODELS COME INTO BETTER AGREEMENT WILL
CONTINUE GOING SLIGHT CHC POPS IN FCST FOR MONDAY INTO TUESDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 648 AM EST WED MAR 6 2013
A WEAK TROUGH MOVING THROUGH THE AREA WILL BRING LIGHT SNOW TO ALL
TAF SITES TODAY...AFFECTING IWD AND CMX THIS MORNING...AND SAW
THROUGH THE AFTERNOON. VIS SHOULD REMAIN GENERALLY IN THE IFR
RANGE...WITH CIGS IN THE MVFR RANGE. UPSLOPE WINDS AT ALL SITES WILL
HELP KEEP CIGS LOWER FOR MUCH OF THE DAY. THE TROUGH WILL MOVE EAST
DURING THE DAY...BUT EXPECT LAKE ENHANCED SNOW SHOWERS TO CONTINUE
INTO THE EVENING NEAR LAKE SUPERIOR. VIS SHOULD IMPROVE AT ALL SITES
BY LATE THIS AFTERNOON WHILE CIGS REMAIN IN THE MVFR RANGE.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 534 AM EST WED MAR 6 2013
A WEAK TROUGH WILL PASS ACROSS LAKE SUPERIOR TODAY AND BRING NW
WINDS OF 15 TO 25 KNOTS TO THE EASTERN HALF OF LAKE SUPERIOR LATE
THIS AFTERNOON THROUGH TONIGHT. A SURFACE RIDGE WILL THEN MOVE
ACROSS THE AREA THURSDAY INTO FRIDAY AND BRING WINDS UNDER 15 KNOTS.
EXPECT SOUTH WINDS TO INCREASE TO 15 TO 25 KNOTS BY FRIDAY AFTERNOON
FOR CENTRAL AND EASTERN LAKE SUPERIOR. LIGHT WINDS WILL PREVAIL
AGAIN SATURDAY INTO SUNDAY BEFORE A COLD FRONT CROSSES LAKE SUPERIOR
AND USHERS IN NW WINDS OF 15 TO 25 KNOTS OVER THE ENTIRE LAKE SUNDAY
AFTERNOON AND EVENING.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...SRF
SHORT TERM...TK
LONG TERM...VOSS
AVIATION...TK
MARINE...TK
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
649 AM EST WED MAR 6 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 534 AM EST WED MAR 6 2013
INITIAL CONCERNS THIS MORNING COME FROM WIDESPREAD -FZDZ ACROSS THE
NORTHERN CWA. PROFILE TEMPS AT OR ABOVE -10C ARE ALLOWING FOR PRECIP
TO STAY GENERALLY IN LIQUID FORM. THERE HAVE BEEN REPORTS OF ROADS
BECOMING SLIPPERY...AND A DECENT GLAZE HAS BEEN OBSERVED AT OUR
OFFICE. HAVE INCREASED POPS TO WIDESPREAD -FZDZ EARLY THIS
MORNING...AND ISSUED A SPECIAL WX STATEMENT TO ADVISE CAUTION
THROUGH THE MORNING COMMUTE. -FZDZ SHOULD TURN OVER TO SNOW BY
SUNRISE AS TEMPS ALOFT COOL IN RESPONSE TO THE TROUGH.
TODAY...MAIN FOCUS IS ON SNOW POTENTIAL FOR THE NORTHERN HALF
THROUGHOUT THE DAY. A VERY WELL DEFINED SHORTWAVE TROUGH OVER FAR
WESTERN ONTARIO IS ROTATING AROUND THE BASE OF A LARGE SCALE TROUGH
OVER CENTRAL CANADA. WIDESPREAD LIGHT SNOW IS CURRENTLY MOVING
ACROSS FAR NE MN AND WESTERN LAKE SUPERIOR AHEAD OF THIS TROUGH.
FORCING APPEARS TO BE TIED TO AN ACTIVE REGION OF FRONTOGENESIS
AROUND 600MB.
STRONGEST FORCING ALONG THE FRONTOGENESIS BAND IS PUSHING
NORTHEASTWARD AS THE SHORTWAVE PIVOTS AROUND THE LARGE SCALE TROUGH.
THIS TREND IS QUITE EVIDENT ON WV IMAGERY EARLY THIS MORNING.
MEANWHILE...A FAIRLY DEFINED SHORTWAVE TROUGH THAT WAS OBSERVED ON
WV IMAGERY AND RAP ANALYSIS OVER SOUTHERN MANITOBA EARLY THIS
MORNING IS QUICKLY LOSING ITS DEFINITION. THOUGH MODELS ARE SHOWING
THAT THIS SMALL SHORTWAVE WILL REINFORCE THE DECAYING WAVE OVER
MN...HAVE A FEELING MODELS ARE NOT HANDLING THE SMALL NATURE OF THE
WAVE VERY WELL. THE NAM APPEARS TO BE MOST AGGRESSIVE WITH THIS
SYSTEM...SO WILL LOOK MORE TOWARD THE GFS/RAP FOR SHORT TERM
GUIDANCE.
MAIN PRECIP IS FOLLOWING BEHIND A WEAK SFC TROUGH. WINDS WILL BACK
MORE OUT OF THE NORTHWEST BEHIND THE TROUGH...SO BEST PRECIP CHANCES
WILL FOCUS IN UPSLOPE REGIONS FAVORED BY NW WINDS. OVERALL...HAVE
CUT BACK ON POP/QPF/SNOW AMOUNTS...BUT NOT MUCH AS THE LEFT EXIT OF
A STRENGTHENING 100KT UPPER JET WILL MOVE TROUGH NORTHERN WI. NOT
GREAT ALIGNMENT WITH BEST MID-LEVEL Q-VECTOR CONV OVER AND NORTH OF
LAKE SUPERIOR...BUT ENOUGH TO KEEP SLIGHT CHANCE POPS ALONG THE WI
BORDER.
OVERALL EXPECTATION IS FOR AROUND AN INCH OF SNOW FOR MOST LOCATIONS
ALONG LAKE SUPERIOR...WITH UP TO 2 INCHES FOR THE HIGHER TERRAIN.
ONLY A DUSTING IS EXPECTED FOR THE SOUTHERN CWA.
TONIGHT...MAIN FOCUS TURNS TO LINGERING CLOUD COVER AND HOW IT WILL
AFFECT LOW TEMPS. SUBSIDENCE BEHIND THE SHORTWAVE QUICKLY TAKES HOLD
LATE THIS AFTERNOON ACROSS THE WEST HALF...LEADING TO A SHALLOW
STRATUS DECK. ONLY A COUPLE MODELS ARE MORE AGGRESSIVE WITH KEEPING
CLOUDS AROUND. GIVEN THAT THE MARCH SUN SHOULD BE MORE EFFICIENT IN
SOMEWHAT MIXING OUT LOW STRATUS LATE THIS AFTERNOON...FEELING IS
THAT LOCATIONS AWAY FROM UPSLOPE INFLUENCE IN THE WEST WILL SEE
ENOUGH CLEARING TO ALLOW FOR DECENT COOLING OVERNIGHT. LOWERED TEMPS
A FEW DEGREES ALONG THE BORDER...AND WOULD NOT BE SURPRISED IF LOWS
DROP BELOW ZERO IN A FEW SPOTS WELL INLAND.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 534 AM EST WED MAR 6 2013
HIGH PRESSURE BUILDING OVER THE AREA WILL WEAKEN NRLY WINDS
EVENTUALLY CAUSING THEM TO BECOME VARIABLE OVER THE WEST. WITH THE
STRENGTHENING SUBSIDENCE INVERSION...THE QUESTION FOR THURSDAY WILL
BE IF CLOUDS SCOUR OUT. PER PREV FCST...WILL HOLD ONTO THE CLOUDS
THE LONGEST OVER THE EAST WHERE THE NORTHWEST WINDS WILL BE MOST
PERSISTENT. ELSEWHERE...WENT WITH MORE OF A PARTLY CLOUDY TO MOSTLY
SUNNY SKY AS DIURNAL MIXING SHOULD HELP ERODE CLOUDS.
UPPER RIDGE OVER THE AREA THURSDAY NIGHT INTO FRIDAY WILL MAINTAIN
DRY WEATHER. WITH LIGHT WINDS AND CLEAR SKIES UNDER SFC RIDGE
AXIS...DECIDED TO LOWER MIN TEMPS THU NIGHT INTO THE SINGLE DIGITS
ABV ZERO OVER CENTRAL AND ERN INTERIOR. INCREASING CLOUDS AND ONSET
OF RETURN FLOW SRLY WINDS...WILL KEEP TEMPS MORE IN THE LOW TO MID
TEENS WEST. WARM ADVECTION AHEAD OF SHORTWAVE AND ASSOC JET MAX
MOVING ACROSS THE NRN PLAINS AND SCNTRL CANADA SHOULD RESULT IN
INCREASING MID AND HIGH CLOUDS ON FRIDAY. WITH INCREASING SRLY
FLOW...LOOK FOR TEMPS TO REACH WELL INTO THE 30S OVER WEST
HALF...PERHAPS EVEN REACHING 40F FOR DOWNSLOPING LOCATIONS ALONG
LAKE SUPERIOR. FLOW OFF LAKE MICHIGAN WILL KEEP THE EAST COOLER WITH
HIGHS GENERALLY IN THE LOWER TO MID 30S.
BY SATURDAY...AN UPPER TROUGH AND ASSOC CLOSED LOW WILL BE
PARKED OVER THE SOUTHWEST CONUS AND A NORTHERN STREAM TROUGH WILL BE
MOVING THROUGH MANITOBA/SASKATCHEWAN. THE 00Z GFS AND GEM-NH SEEM TO
INDICATE MORE PHASING OF THESE FEATURES THAN THE 00Z ECMWF BUT EVEN
THE ECMWF SHOWS SOME SHORTWAVE ENERGY EJECTING NE FM TROUGH OVER THE
SOUTHWEST CONUS AND MERGING WITH VIGOROUS NRN STREAM SHORTWAVE
MOVING ACROSS THE UPPER GREAT LAKES. THE NRN STREAM SHORTWAVE WILL
HAVE MORE OF AN IMPACT ON OUR WEATHER AND GIVEN THAT THE BEST
FORCING STAYS GENERALLY NW OF THE FCST AREA ALONG TRACK OF
SHORTWAVE...THE BEST CHC FOR PCPN SHOULD BE OVER THE FAR WRN FCST
AREA. DYNAMICS AND MODEL AVG QPF ARGUE FOR LIKELY POPS WEST ON
SATURDAY TAPERING TO LOW CHC POPS EAST. COULD SEE NEAR ADVISORY
SNOWFALL FOR SOME LOCATIONS OVER WESTERN UPPER MICHIGAN AND HAVE
DECIDED TO MENTION POSSIBLE ACCUMULATING SNOW IN THE HWO. WITH 850MB
TEMPS ABV 0C OVER THE SOUTH CENTRAL HAVE KEPT IN MENTION OF
RAIN/SNOW MIX FOR THESE LOCATIONS. AS FRONTAL BOUNDARY MOVES EAST
...LOOK FOR HIGHER CHC TO LIKELY POPS TO TRANSLATE OVER MAINLY EAST
HALF SAT NIGHT WHILE STEADY PCPN TAPERS OFF OVER THE WEST LATE SAT
NIGHT.
HIGH PRESSURE BUILDS INTO THE UPPER GREAT LAKES FOR SUNDAY INTO
SUNDAY NIGHT PROVIDING FOR DRIER CONDITIONS BEHIND THE FRONT EXCEPT
FOR THE LINGERING LIGHT LES POSSIBLE ALONG LAKE SUPERIOR. MORE
UNCERTAINTY BY MONDAY AS THE GFS SHOWS PHASING OF SRN STREAM
SHORTWAVE WITH NRN STREAM AND DEVELOPING WOUND UP SFC LOW TRACKING
OVER LOWER MI INTO LAKE HURON. THE GFS SOLN WOULD DRAW IN COLDER AIR
IN A STRONGER CYCLONIC NRLY FLOW FOR POSSIBLE LAKE ENHANCED SNOW.
MEANWHILE...THE ECMWF KEEPS THE SRN STREAM WAVE TRACKING FARTHER SE
THROUGH THE OHIO VALLEY WITH LTL TO NO IMPACT ON OUR WEATHER. THE
ECMWF SHOWS HINT OF ANOTHER WEAK CLIPPER SHORTWAVE MOVING OVER AREA
FOR TUESDAY. FOR NOW...UNTIL MODELS COME INTO BETTER AGREEMENT WILL
CONTINUE GOING SLIGHT CHC POPS IN FCST FOR MONDAY INTO TUESDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 648 AM EST WED MAR 6 2013
A WEAK TROUGH MOVING THROUGH THE AREA WILL BRING LIGHT SNOW TO ALL
TAF SITES TODAY...AFFECTING IWD AND CMX THIS MORNING...AND SAW
THROUGH THE AFTERNOON. VIS SHOULD REMAIN GENERALLY IN THE IFR
RANGE...WITH CIGS IN THE MVFR RANGE. UPSLOPE WINDS AT ALL SITES WILL
HELP KEEP CIGS LOWER FOR MUCH OF THE DAY. THE TROUGH WILL MOVE EAST
DURING THE DAY...BUT EXPECT LAKE ENHANCED SNOW SHOWERS TO CONTINUE
INTO THE EVENING NEAR LAKE SUPERIOR. VIS SHOULD IMPROVE AT ALL SITES
BY LATE THIS AFTERNOON WHILE CIGS REMAIN IN THE MVFR RANGE.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 534 AM EST WED MAR 6 2013
A WEAK TROUGH WILL PASS ACROSS LAKE SUPERIOR TODAY AND BRING NW
WINDS OF 15 TO 25 KNOTS TO THE EASTERN HALF OF LAKE SUPERIOR LATE
THIS AFTERNOON THROUGH TONIGHT. A SURFACE RIDGE WILL THEN MOVE
ACROSS THE AREA THURSDAY INTO FRIDAY AND BRING WINDS UNDER 15 KNOTS.
EXPECT SOUTH WINDS TO INCREASE TO 15 TO 25 KNOTS BY FRIDAY AFTERNOON
FOR CENTRAL AND EASTERN LAKE SUPERIOR. LIGHT WINDS WILL PREVAIL
AGAIN SATURDAY INTO SUNDAY BEFORE A COLD FRONT CROSSES LAKE SUPERIOR
AND USHERS IN NW WINDS OF 15 TO 25 KNOTS OVER THE ENTIRE LAKE SUNDAY
AFTERNOON AND EVENING.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...TK
LONG TERM...VOSS
AVIATION...TK
MARINE...TK
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
535 AM EST WED MAR 6 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 534 AM EST WED MAR 6 2013
INITIAL CONCERNS THIS MORNING COME FROM WIDESPREAD -FZDZ ACROSS THE
NORTHERN CWA. PROFILE TEMPS AT OR ABOVE -10C ARE ALLOWING FOR PRECIP
TO STAY GENERALLY IN LIQUID FORM. THERE HAVE BEEN REPORTS OF ROADS
BECOMING SLIPPERY...AND A DECENT GLAZE HAS BEEN OBSERVED AT OUR
OFFICE. HAVE INCREASED POPS TO WIDESPREAD -FZDZ EARLY THIS
MORNING...AND ISSUED A SPECIAL WX STATEMENT TO ADVISE CAUTION
THROUGH THE MORNING COMMUTE. -FZDZ SHOULD TURN OVER TO SNOW BY
SUNRISE AS TEMPS ALOFT COOL IN RESPONSE TO THE TROUGH.
TODAY...MAIN FOCUS IS ON SNOW POTENTIAL FOR THE NORTHERN HALF
THROUGHOUT THE DAY. A VERY WELL DEFINED SHORTWAVE TROUGH OVER FAR
WESTERN ONTARIO IS ROTATING AROUND THE BASE OF A LARGE SCALE TROUGH
OVER CENTRAL CANADA. WIDESPREAD LIGHT SNOW IS CURRENTLY MOVING
ACROSS FAR NE MN AND WESTERN LAKE SUPERIOR AHEAD OF THIS TROUGH.
FORCING APPEARS TO BE TIED TO AN ACTIVE REGION OF FRONTOGENESIS
AROUND 600MB.
STRONGEST FORCING ALONG THE FRONTOGENESIS BAND IS PUSHING
NORTHEASTWARD AS THE SHORTWAVE PIVOTS AROUND THE LARGE SCALE TROUGH.
THIS TREND IS QUITE EVIDENT ON WV IMAGERY EARLY THIS MORNING.
MEANWHILE...A FAIRLY DEFINED SHORTWAVE TROUGH THAT WAS OBSERVED ON
WV IMAGERY AND RAP ANALYSIS OVER SOUTHERN MANITOBA EARLY THIS
MORNING IS QUICKLY LOSING ITS DEFINITION. THOUGH MODELS ARE SHOWING
THAT THIS SMALL SHORTWAVE WILL REINFORCE THE DECAYING WAVE OVER
MN...HAVE A FEELING MODELS ARE NOT HANDLING THE SMALL NATURE OF THE
WAVE VERY WELL. THE NAM APPEARS TO BE MOST AGGRESSIVE WITH THIS
SYSTEM...SO WILL LOOK MORE TOWARD THE GFS/RAP FOR SHORT TERM
GUIDANCE.
MAIN PRECIP IS FOLLOWING BEHIND A WEAK SFC TROUGH. WINDS WILL BACK
MORE OUT OF THE NORTHWEST BEHIND THE TROUGH...SO BEST PRECIP CHANCES
WILL FOCUS IN UPSLOPE REGIONS FAVORED BY NW WINDS. OVERALL...HAVE
CUT BACK ON POP/QPF/SNOW AMOUNTS...BUT NOT MUCH AS THE LEFT EXIT OF
A STRENGTHENING 100KT UPPER JET WILL MOVE TROUGH NORTHERN WI. NOT
GREAT ALIGNMENT WITH BEST MID-LEVEL Q-VECTOR CONV OVER AND NORTH OF
LAKE SUPERIOR...BUT ENOUGH TO KEEP SLIGHT CHANCE POPS ALONG THE WI
BORDER.
OVERALL EXPECTATION IS FOR AROUND AN INCH OF SNOW FOR MOST LOCATIONS
ALONG LAKE SUPERIOR...WITH UP TO 2 INCHES FOR THE HIGHER TERRAIN.
ONLY A DUSTING IS EXPECTED FOR THE SOUTHERN CWA.
TONIGHT...MAIN FOCUS TURNS TO LINGERING CLOUD COVER AND HOW IT WILL
AFFECT LOW TEMPS. SUBSIDENCE BEHIND THE SHORTWAVE QUICKLY TAKES HOLD
LATE THIS AFTERNOON ACROSS THE WEST HALF...LEADING TO A SHALLOW
STRATUS DECK. ONLY A COUPLE MODELS ARE MORE AGGRESSIVE WITH KEEPING
CLOUDS AROUND. GIVEN THAT THE MARCH SUN SHOULD BE MORE EFFICIENT IN
SOMEWHAT MIXING OUT LOW STRATUS LATE THIS AFTERNOON...FEELING IS
THAT LOCATIONS AWAY FROM UPSLOPE INFLUENCE IN THE WEST WILL SEE
ENOUGH CLEARING TO ALLOW FOR DECENT COOLING OVERNIGHT. LOWERED TEMPS
A FEW DEGREES ALONG THE BORDER...AND WOULD NOT BE SURPRISED IF LOWS
DROP BELOW ZERO IN A FEW SPOTS WELL INLAND.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 534 AM EST WED MAR 6 2013
HIGH PRESSURE BUILDING OVER THE AREA WILL WEAKEN NRLY WINDS
EVENTUALLY CAUSING THEM TO BECOME VARIABLE OVER THE WEST. WITH THE
STRENGTHENING SUBSIDENCE INVERSION...THE QUESTION FOR THURSDAY WILL
BE IF CLOUDS SCOUR OUT. PER PREV FCST...WILL HOLD ONTO THE CLOUDS
THE LONGEST OVER THE EAST WHERE THE NORTHWEST WINDS WILL BE MOST
PERSISTENT. ELSEWHERE...WENT WITH MORE OF A PARTLY CLOUDY TO MOSTLY
SUNNY SKY AS DIURNAL MIXING SHOULD HELP ERODE CLOUDS.
UPPER RIDGE OVER THE AREA THURSDAY NIGHT INTO FRIDAY WILL MAINTAIN
DRY WEATHER. WITH LIGHT WINDS AND CLEAR SKIES UNDER SFC RIDGE
AXIS...DECIDED TO LOWER MIN TEMPS THU NIGHT INTO THE SINGLE DIGITS
ABV ZERO OVER CENTRAL AND ERN INTERIOR. INCREASING CLOUDS AND ONSET
OF RETURN FLOW SRLY WINDS...WILL KEEP TEMPS MORE IN THE LOW TO MID
TEENS WEST. WARM ADVECTION AHEAD OF SHORTWAVE AND ASSOC JET MAX
MOVING ACROSS THE NRN PLAINS AND SCNTRL CANADA SHOULD RESULT IN
INCREASING MID AND HIGH CLOUDS ON FRIDAY. WITH INCREASING SRLY
FLOW...LOOK FOR TEMPS TO REACH WELL INTO THE 30S OVER WEST
HALF...PERHAPS EVEN REACHING 40F FOR DOWNSLOPING LOCATIONS ALONG
LAKE SUPERIOR. FLOW OFF LAKE MICHIGAN WILL KEEP THE EAST COOLER WITH
HIGHS GENERALLY IN THE LOWER TO MID 30S.
BY SATURDAY...AN UPPER TROUGH AND ASSOC CLOSED LOW WILL BE
PARKED OVER THE SOUTHWEST CONUS AND A NORTHERN STREAM TROUGH WILL BE
MOVING THROUGH MANITOBA/SASKATCHEWAN. THE 00Z GFS AND GEM-NH SEEM TO
INDICATE MORE PHASING OF THESE FEATURES THAN THE 00Z ECMWF BUT EVEN
THE ECMWF SHOWS SOME SHORTWAVE ENERGY EJECTING NE FM TROUGH OVER THE
SOUTHWEST CONUS AND MERGING WITH VIGOROUS NRN STREAM SHORTWAVE
MOVING ACROSS THE UPPER GREAT LAKES. THE NRN STREAM SHORTWAVE WILL
HAVE MORE OF AN IMPACT ON OUR WEATHER AND GIVEN THAT THE BEST
FORCING STAYS GENERALLY NW OF THE FCST AREA ALONG TRACK OF
SHORTWAVE...THE BEST CHC FOR PCPN SHOULD BE OVER THE FAR WRN FCST
AREA. DYNAMICS AND MODEL AVG QPF ARGUE FOR LIKELY POPS WEST ON
SATURDAY TAPERING TO LOW CHC POPS EAST. COULD SEE NEAR ADVISORY
SNOWFALL FOR SOME LOCATIONS OVER WESTERN UPPER MICHIGAN AND HAVE
DECIDED TO MENTION POSSIBLE ACCUMULATING SNOW IN THE HWO. WITH 850MB
TEMPS ABV 0C OVER THE SOUTH CENTRAL HAVE KEPT IN MENTION OF
RAIN/SNOW MIX FOR THESE LOCATIONS. AS FRONTAL BOUNDARY MOVES EAST
...LOOK FOR HIGHER CHC TO LIKELY POPS TO TRANSLATE OVER MAINLY EAST
HALF SAT NIGHT WHILE STEADY PCPN TAPERS OFF OVER THE WEST LATE SAT
NIGHT.
HIGH PRESSURE BUILDS INTO THE UPPER GREAT LAKES FOR SUNDAY INTO
SUNDAY NIGHT PROVIDING FOR DRIER CONDITIONS BEHIND THE FRONT EXCEPT
FOR THE LINGERING LIGHT LES POSSIBLE ALONG LAKE SUPERIOR. MORE
UNCERTAINTY BY MONDAY AS THE GFS SHOWS PHASING OF SRN STREAM
SHORTWAVE WITH NRN STREAM AND DEVELOPING WOUND UP SFC LOW TRACKING
OVER LOWER MI INTO LAKE HURON. THE GFS SOLN WOULD DRAW IN COLDER AIR
IN A STRONGER CYCLONIC NRLY FLOW FOR POSSIBLE LAKE ENHANCED SNOW.
MEANWHILE...THE ECMWF KEEPS THE SRN STREAM WAVE TRACKING FARTHER SE
THROUGH THE OHIO VALLEY WITH LTL TO NO IMPACT ON OUR WEATHER. THE
ECMWF SHOWS HINT OF ANOTHER WEAK CLIPPER SHORTWAVE MOVING OVER AREA
FOR TUESDAY. FOR NOW...UNTIL MODELS COME INTO BETTER AGREEMENT WILL
CONTINUE GOING SLIGHT CHC POPS IN FCST FOR MONDAY INTO TUESDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1235 AM EST WED MAR 6 2013
DRY AIR CONTINUES TO DELAY THINGS AND PUSHED THE TIMING BACK A BIT.
WITH A DISTURBANCE ARRIVING OVER THE UPPER LAKES LATE TONIGHT/WED
MORNING...-SHSN WILL INCREASE IN COVERAGE AND INTENSITY DURING THIS
FCST PERIOD. AT KIWD...EXPECT MVFR CONDITIONS OVERNIGHT WITH -SHSN
DEVELOPING. CONDITIONS SHOULD SETTLE TO IFR BY MORNING UNDER
FAVORABLE UPSLOPE FLOW. AT KCMX...CONDITIONS SHOULD STAY MVFR
OVERNIGHT BEFORE FALLING TO PREVAILING IFR BY MORNING. AT
KSAW...MVFR CONDITIONS WILL CONTINUE AS -SHSN DEVELOP LATE TONIGHT.
FAVORABLE CONVERGENT UPSLOPE FLOW WED MORNING WILL RESULT IN CIGS
FALLING TO LIFR. IMPROVEMENT SHOULD OCCUR AT ALL SITES LATER WED
MORNING INTO THE EARLY AFTERNOON WHERE MVFR CONDITIONS WILL THEN
PREVAIL.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 534 AM EST WED MAR 6 2013
A WEAK TROUGH WILL PASS ACROSS LAKE SUPERIOR TODAY AND BRING NW
WINDS OF 15 TO 25 KNOTS TO THE EASTERN HALF OF LAKE SUPERIOR LATE
THIS AFTERNOON THROUGH TONIGHT. A SURFACE RIDGE WILL THEN MOVE
ACROSS THE AREA THURSDAY INTO FRIDAY AND BRING WINDS UNDER 15 KNOTS.
EXPECT SOUTH WINDS TO INCREASE TO 15 TO 25 KNOTS BY FRIDAY AFTERNOON
FOR CENTRAL AND EASTERN LAKE SUPERIOR. LIGHT WINDS WILL PREVAIL
AGAIN SATURDAY INTO SUNDAY BEFORE A COLD FRONT CROSSES LAKE SUPERIOR
AND USHERS IN NW WINDS OF 15 TO 25 KNOTS OVER THE ENTIRE LAKE SUNDAY
AFTERNOON AND EVENING.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...TK
LONG TERM...VOSS
AVIATION...07
MARINE...TK
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
341 AM EST WED MAR 6 2013
.UPDATE...
ISSUED AT 340 AM EST WED MAR 6 2013
QUICK UPDATE THIS MORNING CONCERNING FREEZING DRIZZLE ACROSS THE
NORTHERN CWA. PROFILE TEMPS AT OR ABOVE -10C ARE ALLOWING FOR PRECIP
TO STAY GENERALLY IN LIQUID FORM. THERE HAVE BEEN REPORTS OF ROADS
BECOMING SLIPPERY...AND A DECENT GLAZE HAS BEEN OBSERVED AT OUR
OFFICE. HAVE INCREASED POPS TO WIDESPREAD -FZDZ EARLY THIS
MORNING...AND ISSUED A SPECIAL WX STATEMENT TO ADVISE CAUTION
THROUGH THE MORNING COMMUTE.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 407 PM EST TUE MAR 5 2013
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A VIGOROUS SHORTWAVE
DROPPING SE INTO THE MID MISSISSIPPI VALLEY. WAVE IS BEING FORCED SE
BY MID LEVEL HIGH OVER QUEBEC. AS A RESULT...SYSTEM SNOW HAS PAST BY
TO THE W AND S OF UPPER MI TODAY. SOME VERY LIGHT LES IS OCCURRING
IN E TO NE FLOW ACROSS LAKE SUPERIOR INTO THE KEWEENAW AND NCNTRL
UPPER MI AS TEMPS AT THE BASE OF A LOW 3KFT INVERSION ARE JUST
SUFFICIENT FOR LES AT -11C. UNDER DOWNSLOPING E TO NE LOW-LEVEL
WINDS...THE ERN FCST AREA HAS ENJOYED A SUNNY DAY TODAY.
VIGOROUS SHORTWAVE/MID LEVEL LOW OVER THE MID MISSISSIPPI VALLEY
WILL MOVE TO VCNTY OF NC BY WED MORNING AND WILL HAVE LITTLE IMPACT
ON WEATHER HERE. WHAT WILL BE A FACTOR IS A NRN STREAM SHORTWAVE
THAT WILL BE DRIFTING INTO THE UPPER LAKES LATE TONIGHT/WED...
BRINGING A DECENT AREA OF DEEP LAYER FORCING PER QVECTORS. THE
APPROACHING SHORTWAVE WILL HELP SHARPEN LOW-LEVEL CYCLONIC N TO NE
FLOW ACROSS LAKE SUPERIOR TONIGHT/WED MORNING BEFORE WINDS SHIFT NW
WED AS THE WAVE REACHES THE AREA. WHILE LOW-LEVEL THERMAL PROFILE
CHANGES VERY LITTLE...OVERWATER INSTABILITY IS MORE THAN SUFFICIENT
FOR LAKE ENHANCEMENT...AND THE FACT THAT SOME VERY LIGHT LES IS
ALREADY OCCURRING SUGGESTS THERE SHOULD BE A DECENT UPTICK IN LES
TONIGHT/WED MORNING. WITH ALL MODEL GUIDANCE SHOWING A SSE TO NNW
ORIENTED SFC TROF DEVELOPING ACROSS ROUGHLY CNTRL LAKE SUPERIOR...IT
WOULD APPEAR THAT NW AND NCNTRL UPPER MI SHOULD BE FAVORED FOR MORE
PERSISTENT SNOW. SNOW TO WATER RATIOS SHOULD BE ON THE LOW SIDE
10-15 TO 1...EXCEPT IN THE VCNTY/ALONG THE AFORENTIONED SFC TROF
WHERE DEEPER VERTICAL MOTION...THOUGH NOT STRONG...SHOULD INTERSECT
THE DGZ AND POSSIBLY BOOST RATIOS TOWARD 20 TO 1. AT THIS POINT...IT
APPEARS ACCUMULATIONS UPWARDS OF AROUND 3 INCHES ARE POSSIBLE OVER
NW/NCNTRL HIGHER TERRAIN TONIGHT/WED MORNING. ACCUMULATIONS SHOULD
BE A LITTLE LESS FARTHER W TOWARD KIWD. IT REALLY WON`T BE UNTIL
LATER WED MORNING/AFTN WHEN SFC TROF PASSES THAT SNOW REACHES THE NE
FCST AREA. AWAY FROM LAKE ENHANCEMENT...EXPECT SOME -SN/-SHSN TIED
TO SHORT PERIOD OF STRONGER FORCING ASSOCIATED WITH SHORTWAVE. -SHSN
WILL DIMINISH W TO E WED AFTN AND MAY END OVER THE W.
TEMPS TONIGHT ARE FAIRLY STRAIGHTFORWARD WITH CLOUD COVER LIMITING
TEMP FALL. ONE EXCEPTION IS THE ERN FCST AREA AS IT`S UNCERTAIN WHEN
CLOUDS WILL INCREASE SUFFICIENTLY TO SLOW/STOP TEMP FALL THERE
TONIGHT. GIVEN THAT IT`S SUNNY IN THAT AREA NOW...AND SATELLITE
IMAGERY SHOWS NO TREND TO CLOUD UP SOON...TEMPS COULD PLUMMET
QUICKLY THIS EVENING. FCST WILL SHOW MINS IN THE MID TEENS...BUT
IT`S QUITE POSSIBLE TEMPS COULD FALL WELL DOWN INTO THE SINGLE
DIGITS DURING THE EVENING IF IT REMAINS MOSTLY CLEAR. MID 20S TO LWR
30S SHOULD BE THE RULE WED.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 407 PM EST TUE MAR 5 2013
LINGERING SURFACE TROUGH AND NORTHERN STREAM SHORTWAVE WILL BE
SLIDING EAST ACROSS EASTERN LAKE SUPERIOR ON WEDNESDAY EVENING WHILE
AN AREA OF HIGH PRESSURE BUILDS INTO THE UPPER GREAT LAKES. WITH
900MB TEMPS STILL AROUND -12C AND ENOUGH LOW LEVEL MOISTURE BELOW
THE 3-4KFT INVERSION...SHOULD STILL SEE LOW CLOUDS ACROSS THE AREA
DURING THE EVENING IN THE NORTH-NORTHWEST WIND LOCATIONS. DURING THE
EVENING...WOULD EXPECT ISOLATED/SCATTERED SNOW SHOWERS IN THOSE SAME
WIND FAVORED LOCATIONS. WITH A LITTLE DEEPER MOISTURE OVER THE
EASTERN LOCATIONS...MAINLY FROM MUNISING EASTWARD...WOULD EXPECT
ISOLATED LIGHT SNOW SHOWERS TO CONTINUE THROUGH THE NIGHT. OVER THE
WEST...THE INFLUENCE OF THE HIGH WILL ALLOW THE FLOW TO BECOME
ANTI-CYCLONIC THROUGH THE NIGHT AND INCREASE THE DRY AIR OVER THE
WESTERN LAKE...SLOWLY DECREASING THE CLOUDS IN THAT AREA. THIS
DECREASE IN CLOUDS LEADS TO UNCERTAINTY IN THE LOWS OVER THE WESTERN
CWA. WITH LIGHT WINDS AND PWATS AROUND 50 PERCENT OF
NORMAL...LOCATIONS THAT DO CLEAR OUT WILL LIKELY FALL INTO THE
SINGLE DIGITS AND WOULDN/T BE SURPRISED TO SEE A FEW BELOW ZERO
READINGS IN THE COLD SPOTS OF EASTERN GOGEBIC AND IRON COUNTY.
THE HIGH WILL CONTINUE TO MOVE OVER THE AREA ON THURSDAY...CAUSING
WINDS TO BECOME MORE VARIABLE. WITH THE STRENGTHENING SUBSIDENCE
INVERSION...THE QUESTION FOR THURSDAY WILL BE WHERE THE CLOUDS WILL
BE LOCATED AND IF/WHEN THEY WILL MIX OUT. WILL HOLD ONTO THE CLOUDS
THE LONGEST OVER THE EAST WHERE THE NORTHWEST WINDS WILL BE MOST
PERSISTENT. ELSEWHERE...WENT WITH MORE OF A PARTLY CLOUDY TO MOSTLY
SUNNY SKY AS DIURNAL MIXING WILL LIKELY EAT AWAY AT THE CLOUDS.
UPPER RIDGE BUILDS OVER THE AREA ON THURSDAY NIGHT INTO
FRIDAY...WHICH WILL KEEP THE AREA DRY AND ONLY PRODUCE SOME
MID-HIGH CLOUDS STREAMING ACROSS THE AREA. BY FRIDAY NIGHT...AN
UPPER TROUGH WILL BE SITTING OVER THE SOUTHWEST CONUS AND A
NORTHERN STREAM TROUGH WILL BE MOVING THROUGH
MANITOBA/SASKATCHEWAN. THE QUESTION BECOMES WHETHER THESE TWO
TROUGHS WILL SEPARATE OR STAY TOGETHER...WHICH THEN INFLUENCES THE
FORECAST INTO THE FIRST PART OF NEXT WEEK. THE LATEST TRENDS IN THE
12Z MODEL RUNS IS TO KEEP THE WAVES PHASED ENOUGH THROUGH THE
WEEKEND DUE TO A STRONGER NORTHERN STREAM WAVE. THIS IN TURN LEADS
TO STRONGER FORCING WITH THE SURFACE TROUGH MOVING THROUGH SATURDAY
INTO SATURDAY EVENING. WITH THIS STRONGER WAVE AND INCREASED
SOUTHERLY FLOW AHEAD OF THE SYSTEM...MODELS HAVE TRENDED UP WITH
THE QPF...ESPECIALLY OVER THE WESTERN HALF OF THE CWA. HAVE TRENDED
POPS UP FOR THIS PERIOD AND WITH SOME OF THE QPF AMOUNTS SHOWN ON
THE 12Z RUNS...COULD SEE NEAR ADVISORY SNOWFALL FOR SOME LOCATIONS
OVER WESTERN UPPER MICHIGAN. WON/T MENTION THIS IN THE HWO AT THIS
POINT WITH THE WAY THE MODELS HAVE BEEN VARYING...BUT WILL BE
SOMETHING TO WATCH. FINALLY...LOOKING AT MODEL SOUNDINGS...THEY TRY
TO NOSE TEMPS ABOVE 0C AROUND 850MB OVER THE SOUTH CENTRAL WHICH
COULD LEAD TO SOME MELTING ALONG THE ISOTHERMAL LAYER TO THE
SURFACE. THUS...ADDED A MIX OF RAIN/SNOW TO THAT AREA.
HIGH PRESSURE WILL LIKELY BUILD INTO THE UPPER GREAT LAKES FOR
SUNDAY AND THE FIRST PART OF MONDAY...BEFORE THE NEARLY
CLOSED SOUTHERN STREAM TROUGH DRIFTS OUT OF THE SOUTHWEST CONUS.
WHILE THIS SYSTEM WAS LOOKING LIKE IT WAS GOING TO MOVE TOWARDS THE
UPPER GREAT LAKES ON THE 12Z RUNS YESTERDAY...THE LATEST TRENDS
HAVE IT MOVING MORE THROUGH THE OHIO RIVER VALLEY. THEREFORE...HAVE
TRENDED POPS DOWN FOR THE MONDAY PERIOD AND IF THE TREND CONTINUES
THEY MAY NEED TO BE REMOVED COMPLETELY.
AS FOR TEMPERATURES DURING THE LONG TERM PERIOD...IT LOOKS TO BE
FAIRLY NORMAL WITH A FEW DAYS OF SLIGHTLY ABOVE NORMAL HIGHS
THROUGH THE WEEKEND.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1235 AM EST WED MAR 6 2013
DRY AIR CONTINUES TO DELAY THINGS AND PUSHED THE TIMING BACK A BIT.
WITH A DISTURBANCE ARRIVING OVER THE UPPER LAKES LATE TONIGHT/WED
MORNING...-SHSN WILL INCREASE IN COVERAGE AND INTENSITY DURING THIS
FCST PERIOD. AT KIWD...EXPECT MVFR CONDITIONS OVERNIGHT WITH -SHSN
DEVELOPING. CONDITIONS SHOULD SETTLE TO IFR BY MORNING UNDER
FAVORABLE UPSLOPE FLOW. AT KCMX...CONDITIONS SHOULD STAY MVFR
OVERNIGHT BEFORE FALLING TO PREVAILING IFR BY MORNING. AT
KSAW...MVFR CONDITIONS WILL CONTINUE AS -SHSN DEVELOP LATE TONIGHT.
FAVORABLE CONVERGENT UPSLOPE FLOW WED MORNING WILL RESULT IN CIGS
FALLING TO LIFR. IMPROVEMENT SHOULD OCCUR AT ALL SITES LATER WED
MORNING INTO THE EARLY AFTERNOON WHERE MVFR CONDITIONS WILL THEN
PREVAIL.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 407 PM EST TUE MAR 5 2013
NE TO N WINDS OF 15-25KT WILL BE THE RULE ACROSS LAKE SUPERIOR
TONIGHT...THOUGH 20-30KT WINDS WILL LINGER OVER THE WRN PORTION OF
THE LAKE INTO THE EVENING HRS BEFORE PRES GRADIENT BEGINS TO RELAX.
WINDS WILL FALL OFF TO UNDER 20KT OVER WRN LAKE SUPERIOR WED. OVER
ERN LAKE SUPERIOR...TIGHTER PRES GRADIENT WILL ALLOW 15-25KT WINDS
TO PERSIST INTO EARLY THU MORNING. HIGH PRES RIDGE PASSING OVER THE
AREA WILL THEN LEAD TO WINDS UNDER 20KT ACROSS THE LAKE THU/FRI.
ALTHOUGH A LOW PRES TROF WILL PASS ACROSS LAKE SUPERIOR LATER
SAT/EARLY SUN...PRES GRADIENT REMAINS WEAK...KEEPING WINDS MOSTLY
UNDER 20KT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...TK
SHORT TERM...ROLFSON
LONG TERM...SRF
AVIATION...07
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1236 AM EST WED MAR 6 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 407 PM EST TUE MAR 5 2013
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A VIGOROUS SHORTWAVE
DROPPING SE INTO THE MID MISSISSIPPI VALLEY. WAVE IS BEING FORCED SE
BY MID LEVEL HIGH OVER QUEBEC. AS A RESULT...SYSTEM SNOW HAS PAST BY
TO THE W AND S OF UPPER MI TODAY. SOME VERY LIGHT LES IS OCCURRING
IN E TO NE FLOW ACROSS LAKE SUPERIOR INTO THE KEWEENAW AND NCNTRL
UPPER MI AS TEMPS AT THE BASE OF A LOW 3KFT INVERSION ARE JUST
SUFFICIENT FOR LES AT -11C. UNDER DOWNSLOPING E TO NE LOW-LEVEL
WINDS...THE ERN FCST AREA HAS ENJOYED A SUNNY DAY TODAY.
VIGOROUS SHORTWAVE/MID LEVEL LOW OVER THE MID MISSISSIPPI VALLEY
WILL MOVE TO VCNTY OF NC BY WED MORNING AND WILL HAVE LITTLE IMPACT
ON WEATHER HERE. WHAT WILL BE A FACTOR IS A NRN STREAM SHORTWAVE
THAT WILL BE DRIFTING INTO THE UPPER LAKES LATE TONIGHT/WED...
BRINGING A DECENT AREA OF DEEP LAYER FORCING PER QVECTORS. THE
APPROACHING SHORTWAVE WILL HELP SHARPEN LOW-LEVEL CYCLONIC N TO NE
FLOW ACROSS LAKE SUPERIOR TONIGHT/WED MORNING BEFORE WINDS SHIFT NW
WED AS THE WAVE REACHES THE AREA. WHILE LOW-LEVEL THERMAL PROFILE
CHANGES VERY LITTLE...OVERWATER INSTABILITY IS MORE THAN SUFFICIENT
FOR LAKE ENHANCEMENT...AND THE FACT THAT SOME VERY LIGHT LES IS
ALREADY OCCURRING SUGGESTS THERE SHOULD BE A DECENT UPTICK IN LES
TONIGHT/WED MORNING. WITH ALL MODEL GUIDANCE SHOWING A SSE TO NNW
ORIENTED SFC TROF DEVELOPING ACROSS ROUGHLY CNTRL LAKE SUPERIOR...IT
WOULD APPEAR THAT NW AND NCNTRL UPPER MI SHOULD BE FAVORED FOR MORE
PERSISTENT SNOW. SNOW TO WATER RATIOS SHOULD BE ON THE LOW SIDE
10-15 TO 1...EXCEPT IN THE VCNTY/ALONG THE AFORENTIONED SFC TROF
WHERE DEEPER VERTICAL MOTION...THOUGH NOT STRONG...SHOULD INTERSECT
THE DGZ AND POSSIBLY BOOST RATIOS TOWARD 20 TO 1. AT THIS POINT...IT
APPEARS ACCUMULATIONS UPWARDS OF AROUND 3 INCHES ARE POSSIBLE OVER
NW/NCNTRL HIGHER TERRAIN TONIGHT/WED MORNING. ACCUMULATIONS SHOULD
BE A LITTLE LESS FARTHER W TOWARD KIWD. IT REALLY WON`T BE UNTIL
LATER WED MORNING/AFTN WHEN SFC TROF PASSES THAT SNOW REACHES THE NE
FCST AREA. AWAY FROM LAKE ENHANCEMENT...EXPECT SOME -SN/-SHSN TIED
TO SHORT PERIOD OF STRONGER FORCING ASSOCIATED WITH SHORTWAVE. -SHSN
WILL DIMINISH W TO E WED AFTN AND MAY END OVER THE W.
TEMPS TONIGHT ARE FAIRLY STRAIGHTFORWARD WITH CLOUD COVER LIMITING
TEMP FALL. ONE EXCEPTION IS THE ERN FCST AREA AS IT`S UNCERTAIN WHEN
CLOUDS WILL INCREASE SUFFICIENTLY TO SLOW/STOP TEMP FALL THERE
TONIGHT. GIVEN THAT IT`S SUNNY IN THAT AREA NOW...AND SATELLITE
IMAGERY SHOWS NO TREND TO CLOUD UP SOON...TEMPS COULD PLUMMET
QUICKLY THIS EVENING. FCST WILL SHOW MINS IN THE MID TEENS...BUT
IT`S QUITE POSSIBLE TEMPS COULD FALL WELL DOWN INTO THE SINGLE
DIGITS DURING THE EVENING IF IT REMAINS MOSTLY CLEAR. MID 20S TO LWR
30S SHOULD BE THE RULE WED.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 407 PM EST TUE MAR 5 2013
LINGERING SURFACE TROUGH AND NORTHERN STREAM SHORTWAVE WILL BE
SLIDING EAST ACROSS EASTERN LAKE SUPERIOR ON WEDNESDAY EVENING WHILE
AN AREA OF HIGH PRESSURE BUILDS INTO THE UPPER GREAT LAKES. WITH
900MB TEMPS STILL AROUND -12C AND ENOUGH LOW LEVEL MOISTURE BELOW
THE 3-4KFT INVERSION...SHOULD STILL SEE LOW CLOUDS ACROSS THE AREA
DURING THE EVENING IN THE NORTH-NORTHWEST WIND LOCATIONS. DURING THE
EVENING...WOULD EXPECT ISOLATED/SCATTERED SNOW SHOWERS IN THOSE SAME
WIND FAVORED LOCATIONS. WITH A LITTLE DEEPER MOISTURE OVER THE
EASTERN LOCATIONS...MAINLY FROM MUNISING EASTWARD...WOULD EXPECT
ISOLATED LIGHT SNOW SHOWERS TO CONTINUE THROUGH THE NIGHT. OVER THE
WEST...THE INFLUENCE OF THE HIGH WILL ALLOW THE FLOW TO BECOME
ANTI-CYCLONIC THROUGH THE NIGHT AND INCREASE THE DRY AIR OVER THE
WESTERN LAKE...SLOWLY DECREASING THE CLOUDS IN THAT AREA. THIS
DECREASE IN CLOUDS LEADS TO UNCERTAINTY IN THE LOWS OVER THE WESTERN
CWA. WITH LIGHT WINDS AND PWATS AROUND 50 PERCENT OF
NORMAL...LOCATIONS THAT DO CLEAR OUT WILL LIKELY FALL INTO THE
SINGLE DIGITS AND WOULDN/T BE SURPRISED TO SEE A FEW BELOW ZERO
READINGS IN THE COLD SPOTS OF EASTERN GOGEBIC AND IRON COUNTY.
THE HIGH WILL CONTINUE TO MOVE OVER THE AREA ON THURSDAY...CAUSING
WINDS TO BECOME MORE VARIABLE. WITH THE STRENGTHENING SUBSIDENCE
INVERSION...THE QUESTION FOR THURSDAY WILL BE WHERE THE CLOUDS WILL
BE LOCATED AND IF/WHEN THEY WILL MIX OUT. WILL HOLD ONTO THE CLOUDS
THE LONGEST OVER THE EAST WHERE THE NORTHWEST WINDS WILL BE MOST
PERSISTENT. ELSEWHERE...WENT WITH MORE OF A PARTLY CLOUDY TO MOSTLY
SUNNY SKY AS DIURNAL MIXING WILL LIKELY EAT AWAY AT THE CLOUDS.
UPPER RIDGE BUILDS OVER THE AREA ON THURSDAY NIGHT INTO
FRIDAY...WHICH WILL KEEP THE AREA DRY AND ONLY PRODUCE SOME
MID-HIGH CLOUDS STREAMING ACROSS THE AREA. BY FRIDAY NIGHT...AN
UPPER TROUGH WILL BE SITTING OVER THE SOUTHWEST CONUS AND A
NORTHERN STREAM TROUGH WILL BE MOVING THROUGH
MANITOBA/SASKATCHEWAN. THE QUESTION BECOMES WHETHER THESE TWO
TROUGHS WILL SEPARATE OR STAY TOGETHER...WHICH THEN INFLUENCES THE
FORECAST INTO THE FIRST PART OF NEXT WEEK. THE LATEST TRENDS IN THE
12Z MODEL RUNS IS TO KEEP THE WAVES PHASED ENOUGH THROUGH THE
WEEKEND DUE TO A STRONGER NORTHERN STREAM WAVE. THIS IN TURN LEADS
TO STRONGER FORCING WITH THE SURFACE TROUGH MOVING THROUGH SATURDAY
INTO SATURDAY EVENING. WITH THIS STRONGER WAVE AND INCREASED
SOUTHERLY FLOW AHEAD OF THE SYSTEM...MODELS HAVE TRENDED UP WITH
THE QPF...ESPECIALLY OVER THE WESTERN HALF OF THE CWA. HAVE TRENDED
POPS UP FOR THIS PERIOD AND WITH SOME OF THE QPF AMOUNTS SHOWN ON
THE 12Z RUNS...COULD SEE NEAR ADVISORY SNOWFALL FOR SOME LOCATIONS
OVER WESTERN UPPER MICHIGAN. WON/T MENTION THIS IN THE HWO AT THIS
POINT WITH THE WAY THE MODELS HAVE BEEN VARYING...BUT WILL BE
SOMETHING TO WATCH. FINALLY...LOOKING AT MODEL SOUNDINGS...THEY TRY
TO NOSE TEMPS ABOVE 0C AROUND 850MB OVER THE SOUTH CENTRAL WHICH
COULD LEAD TO SOME MELTING ALONG THE ISOTHERMAL LAYER TO THE
SURFACE. THUS...ADDED A MIX OF RAIN/SNOW TO THAT AREA.
HIGH PRESSURE WILL LIKELY BUILD INTO THE UPPER GREAT LAKES FOR
SUNDAY AND THE FIRST PART OF MONDAY...BEFORE THE NEARLY
CLOSED SOUTHERN STREAM TROUGH DRIFTS OUT OF THE SOUTHWEST CONUS.
WHILE THIS SYSTEM WAS LOOKING LIKE IT WAS GOING TO MOVE TOWARDS THE
UPPER GREAT LAKES ON THE 12Z RUNS YESTERDAY...THE LATEST TRENDS
HAVE IT MOVING MORE THROUGH THE OHIO RIVER VALLEY. THEREFORE...HAVE
TRENDED POPS DOWN FOR THE MONDAY PERIOD AND IF THE TREND CONTINUES
THEY MAY NEED TO BE REMOVED COMPLETELY.
AS FOR TEMPERATURES DURING THE LONG TERM PERIOD...IT LOOKS TO BE
FAIRLY NORMAL WITH A FEW DAYS OF SLIGHTLY ABOVE NORMAL HIGHS
THROUGH THE WEEKEND.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1235 AM EST WED MAR 6 2013
DRY AIR CONTINUES TO DELAY THINGS AND PUSHED THE TIMING BACK A BIT.
WITH A DISTURBANCE ARRIVING OVER THE UPPER LAKES LATE TONIGHT/WED
MORNING...-SHSN WILL INCREASE IN COVERAGE AND INTENSITY DURING THIS
FCST PERIOD. AT KIWD...EXPECT MVFR CONDITIONS OVERNIGHT WITH -SHSN
DEVELOPING. CONDITIONS SHOULD SETTLE TO IFR BY MORNING UNDER
FAVORABLE UPSLOPE FLOW. AT KCMX...CONDITIONS SHOULD STAY MVFR
OVERNIGHT BEFORE FALLING TO PREVAILING IFR BY MORNING. AT
KSAW...MVFR CONDITIONS WILL CONTINUE AS -SHSN DEVELOP LATE TONIGHT.
FAVORABLE CONVERGENT UPSLOPE FLOW WED MORNING WILL RESULT IN CIGS
FALLING TO LIFR. IMPROVEMENT SHOULD OCCUR AT ALL SITES LATER WED
MORNING INTO THE EARLY AFTERNOON WHERE MVFR CONDITIONS WILL THEN
PREVAIL.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 407 PM EST TUE MAR 5 2013
NE TO N WINDS OF 15-25KT WILL BE THE RULE ACROSS LAKE SUPERIOR
TONIGHT...THOUGH 20-30KT WINDS WILL LINGER OVER THE WRN PORTION OF
THE LAKE INTO THE EVENING HRS BEFORE PRES GRADIENT BEGINS TO RELAX.
WINDS WILL FALL OFF TO UNDER 20KT OVER WRN LAKE SUPERIOR WED. OVER
ERN LAKE SUPERIOR...TIGHTER PRES GRADIENT WILL ALLOW 15-25KT WINDS
TO PERSIST INTO EARLY THU MORNING. HIGH PRES RIDGE PASSING OVER THE
AREA WILL THEN LEAD TO WINDS UNDER 20KT ACROSS THE LAKE THU/FRI.
ALTHOUGH A LOW PRES TROF WILL PASS ACROSS LAKE SUPERIOR LATER
SAT/EARLY SUN...PRES GRADIENT REMAINS WEAK...KEEPING WINDS MOSTLY
UNDER 20KT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...SRF
AVIATION...07
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
406 PM CST WED MAR 6 2013
.DISCUSSION...
TONIGHT...CLOUDS HAVE BEEN THINNING OUT ALL AFTERNOON...AND ITS
CURRENTLY PRETTY CLEAR OVER WRN WI. THE STRATUS DECK IS MORE
EXTENSIVE FURTHER WEST...AND WITH HIGH PRESSURE MOVING OVERHEAD
TONIGHT...THE CLOUDS MAY BECOME TRAPPED UNDER THE INVERSION. THE
FCST HAS TRENDED WARMER FOR OVERNIGHT LOWS /ESPECIALLY ACROSS WC
MN/ WHERE CLOUDS ARE ANTICIPATED TO HANG ON THE LONGEST. TEMPS ARE
EXPECTED TO RANGE FROM THE LOWER TEENS ALONG AND WEST OF THE MN
RIVER...TO NEAR ZERO IN W WI. WHERE CLEARING DOES
OCCUR...RADIATIONAL FOG MAY BECOME AN ISSUE. E CENTRAL MN AND W WI
HAVE THE BEST SHOT OF SEEING PATCHY FOG WHERE SKIES SHOULD BE
CLEAR THE LONGEST. NOT EXPECTING EXTENSIVE DENSE FOG...BUT WOULD
NOT BE SURPRISED IF A FEW SITES DIP AS LOW AS 1/2SM FOR A TIME
EARLY THU AM.
THURSDAY AND FRIDAY...SURFACE HIGH PRES WILL SLIDE E ACRS THE
AREA...RESIDING E OF THE AREA BY THU MRNG. IN CONJUNCTION WILL BE
A LONGWAVE UPPER LEVEL RIDGE THAT WILL GLIDE ACRS THE REGION.
WHILE THE SFC HIGH E OF THE REGION WILL ALLOW FOR A SOUTHERLY
WARMER RETURN SFC FLOW...THE UPPER RIDGING WILL BRING HIGHER H7
AND H5 HEIGHTS THAT WILL ALSO PROMOTE WAA FOR THE REGION FOR BOTH
THU-FRI. THIS COMBINATION WILL ALSO KEEP ANY SIGNIFICANT WX
SYSTEMS FROM IMPACTING THE REGION SO TEMPERATURES WILL RISE TO
NEAR NORMAL LEVELS...WHICH WILL ACTUALLY SEEM LIKE A SIGNIFICANT
WARMUP FOR THE REGION. HIGHS WILL REACH THE FREEZING MARK ON THU
THEN JUMP TO THE MID AND EVEN UPPER 30S ON FRI. THIS WILL ALLOW
FOR DECENT MELTING OF THE SNOWPACK AND SHOULD CAUSE AN APPRECIABLE
DECREASE IN SNOW DEPTH. CLOUDS WILL BE ON THE INCREASE FRI WHICH
MAY HINDER SOME EVAPORATION BUT THE MELTING SHOULD NOT BE IMPACTED
AS MUCH SIMPLY WITH TEMPERATURES WELL ABOVE THE FREEZING MARK. OF
COURSE...THE MELTING FOLLOWED BY REFREEZING AT NIGHT MAY CAUSE
SOME SLIPPERY ROADS BUT IT IS A LITTLE EARLY TO DETERMINE THE
EXTENT OF SUCH CONCERNS.
FRIDAY NIGHT THROUGH TUESDAY...SEVERAL LOW PRESSURE SYSTEMS LOOK
TO IMPACT THE AREA LATE THIS WEEK INTO EARLY NEXT WEEK WITHIN A
PROGRESSIVE SW FLOW ON THE BACKSIDE OF THE DEPARTING UPPER LEVEL
RIDGE. A LARGE LONGWAVE TROUGH DIGGING INTO THE 4-CORNERS REGION
WILL EJECT A LOW PRESSURE SYSTEM FROM THE COLORADO REGION EWD INTO
THE MID-MISSISSIPPI RIVER VALLEY. HIGH PRES NUDGING DOWN FROM
CENTRAL CANADA WILL KEEP THE BULK OF THIS SYSTEM FROM SHIFTING
N...BUT ENOUGH UPPER LEVEL TROFFING COMBINED WITH AN ATTENDANT SFC
TROUGH WILL ALLOW PRECIPITATION TO DEVELOP FROM S TO N STARTING
FRI NIGHT AND CONTINUING THRU MOST OF THE WEEKEND. THE CONCERN IS
THAT THERE IS LITTLE TO NO COLD AIR ADVECTION ACCOMPANYING THIS
SYSTEM SO TEMPERATURES WILL STILL RANGE THROUGH THE 30S DURING THE
DAYTIME HOURS FRI-SUN AND IN THE 20S TO NEAR 30 FRI NIGHT AND SAT
NIGHT. IN ADDITION...MODEL SOUNDINGS CONTINUE TO ADVERTISE VARYING
AREAS THAT WILL DEAL WITH A SHALLOW WARM AIR LAYER OF VARYING
DEPTHS...MAKING P-TYPE ISSUES HIGHLY COMPLEX. HAVE CONTINUED TO
ADVERTISE A VARIETY OF WINTRY PRECIPITATION FOR THE WEEKEND AND
LATER FORECASTS WILL NEED TO BE ADVERTISED. IN ADDITION...QPF
LOOKS TO BE HIGHLY ELEVATED WITH SOME MODELS SHOWING AT LEAST AN
INCH THROUGH THE WEEKEND...WHICH MAY MAKE FOR HYDROLOGIC
CONCERNS...ESPECIALLY ANY SIGNIFICANT RAINFALL ON TOP OF A DECENT
SNOWPACK. ONCE THIS COMPLEX SYSTEM SHIFTS OFF TO THE SE SUN NIGHT
INTO MON...COLDER HIGH PRES WILL DROP DOWN FROM CANADA MAKING FOR
A DRYING OUT PERIOD MON-TUE ALONG WITH TEMPERATURES BACK DOWN
BELOW NORMAL.
&&
.AVIATION.../18Z TAF ISSUANCE/
MAIN ISSUE THIS TAF PERIOD IS WHAT WILL HAPPEN WITH EXPANSIVE
STRATUS DECK IN PLACE. SFC RIDGE AXIS IS CURRENTLY FROM NEAR SIOUX
FALLS TO BISMARK...WITH CONDS MAINLY VFR WEST OF THIS AXIS. THE
RIDGE WILL SLIDE ACROSS THE MPX AREA TONIGHT...WHICH WOULD IMPLY
SKIES SHOULD CLEAR OUT FROM WEST TO EAST...BUT THIS IS LOOKING
LIKE A SCENARIO WHERE LOW LEVEL MOISTURE GETS TRAPPED BENEATH THE
INVERSION AND IT TAKES A NEW ROUND OF SOLAR MIXING THURSDAY
MORNING TO FINALLY BLAST THE LOW CLOUDS OUT. THIS IS THE SCENARIO
THE HRRR PLAYS OUT AND IN GENERAL WHAT WAS FOLLOWED FOR THESE TAFS.
ONE THING TO WATCH CLOSELY THOUGH THIS AFTERNOON IS WHAT HAPPENS
TO THE HOLE IN STRATUS OVER WRN WI...IF THIS CAN EXPAND SOME THIS
AFTERNOON...THEN THERE IS A GOOD CHANCE THAT SKIES WILL STAY CLEAR
ACROSS ERN TERMINALS. IF THIS HAPPENS...THEN RNH/EAU WILL LIKELY
HAVE TO WORRY ABOUT FOG IN THE MORNING.
KMSP...CONFIDENCE IN OPTIMISTIC SKY FORECAST THIS EVENING IS LOW.
GOING VFR AT 4Z WILL WORK OUT...SO LONG AS THE CLEARING TO THE
EAST CAN EXPAND AND SUSTAIN ITSELF. HOWEVER...COULD VERY WELL SEE
THIS NOT HAPPENING...WITH CIGS REMAINING BETWEEN 020 AND 025 UNTIL
AFTER 12Z THU...WITH THE POTENTIAL FOR GOING BELOW 017 LATE
TONIGHT. FOR WIND DIRECTION...THE SWITCH TOWARD THE SE WILL
HAPPEN OVERNIGHT. WITH SPEEDS UNDER 7 KTS...SHOULD GIVE SOME LEE
WAY IN RUNWAY CONFIG. BY THU MORNING THOUGH...BOTH NAM/GFS SHOW SE
WINDS INCREASING IN INTENSITY...SO WILL MOST LIKELY HAVE TO START
TOMORROW ON THE 12S.
/OUTLOOK FOR KMSP/
FRI...VFR. MVFR CIGS WITH CHANCE OF FZRA/RA LATE FRI NIGHT. SE
WIND 5-10 KTS.
SAT...IFR OR LOWER WITH CHANCE OF FZRA/RA. WINDS E 5 KTS.
SUN...MVFR WITH CHANCE OF -SN EARLY. WINDS N 10-15 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
JPC/JCA
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1235 PM CST WED MAR 6 2013
.UPDATE...
18Z AVIATION DISCUSSION ADDED BELOW.
&&
.PREV DISCUSSION...
/ISSUED 515 AM CST WED MAR 6 2013/
MAIN FORECAST CONCERN IS THE PRECIPITATION TYPE FOR THE UPCOMING
WEEKEND...AND WHETHER THERE WILL BE ICE PROBLEMS.
THE STORM SYSTEM THAT HAS PLAGUED THE UPPER MIDWEST FOR THE PAST
TWO DAYS HAS MOVED SOUTHEAST AND AFFECTING THE MID-ATLANTIC
REGION. RESIDUAL CLOUD COVER AND COOL NORTHERLY FLOW WILL KEEP
TEMPS FROM RISING ABV FREEZING FOR THE MOST PART TODAY.
HOWEVER...THE MARCH SUN ANGLE IS HIGH ENOUGH TO START THE MELTING
PROCESS ACROSS THE REGION...BUT IT SHOULD BE LIMITED WITH THE AMT
OF CLOUD COVER EXPECTED. AS THE SFC RIDGE MOVES OVERHEAD
TONIGHT...SOME FOG WILL DEVELOP...ESPECIALLY ACROSS EASTERN
MN...AND WESTERN WI WHERE WINDS WILL BE LIGHTEST.
AFTER WEDNESDAY...A LARGE RIDGE WILL DEVELOP ACROSS THE UPPER
MIDWEST IN RESPONSE TO A SHARP TROUGH DIGGING INTO THE SW U.S.
THIS WILL ALLOW FOR MUCH WARMER AIR TO SURGE NORTHWARD ACROSS THE
PLAINS...AND THE UPPER MIDWEST BY THE END OF THE WEEK.
BASED ON THE AMT OF MOISTURE EXPECTED AHEAD OF THIS SYSTEM...WHICH
TRANSLATES TO PRECIPITABLE WATER VALUES NEAR 0.80 INCHES /THIS IS
ALMOST TWO STANDARD DEVIATIONS ABV NORMAL FOR MSP/ PRECIPITATION
IS ALMOST CERTAIN BY LATE FRIDAY/SATURDAY. DEPENDING UPON SFC
TEMPS INITIALLY...FREEZING RAIN/SLEET/SNOW WILL OCCUR AT THE
BEGINNING LATE FRIDAY NIGHT/EARLY SATURDAY...BEFORE CHANGING OVER
TO A MIXTURE OF SNOW/RAIN...OR JUST RAIN. DUE TO THE AMT OF WARM
AIR ADVECTING NORTHWARD AND HOW 85H DEW PTS RISE ABV 0C...AM
THINKING THAT MOST OF THE PRECIPITATION WILL BE IN THE FORM OF
LIQUID. ONLY THE FAR NORTH/NW FA MAY SEE A MIXTURE BASED ON THE
MAX WET BULB TEMPS IN THE MIX LAYER UP TO 1KM.
THERE REMAINS A LOT OF CONCERN WITH THE DEEP SNOW PACK ACROSS OUR
REGION...WHICH MAY HOLD DOWN TEMPS INITIALLY...SO A PERIOD OF
SLEET/FREEZING RAIN IS BECOMING LIKELY. WILL UPDATE THE MORNING
HWO BASED ON THIS SCENARIO. QPF AMTS ARE ALSO VERY HIGH...AND MAY
CAUSE SOME FLOODING IF WE GET SOME TYPE OF CONVECTIVE ELEMENT
SATURDAY AFTN. THIS IS MAINLY DUE TO THE FROZEN GROUND AND
ABUNDANT SNOW COVER. AS DEW PTS ARE EXPECTED TO RISE ABV FREEZING
AND THE COMBINATION OF RAIN ON SNOW FALLING...AND POSSIBLY HIGHER
PRECIPITATION RATES...SOME MINOR FLOODING IS POSSIBLE.
A COLD FRONT IS EXPECTED TO MOVE ACROSS THE REGION LATE SATURDAY
AFTN/EVENING...CAUSING THE PRECIPITATION TO SWITCH OVER TO SNOW.
HOWEVER...BUT THAT TIME...MOST OF THE DEEP MOISTURE WOULD BE
GONE...LEAVING ONLY LIGHT SNOW AT BEST.
ALTHOUGH LONG RANGE CLIMATE MODELS ARE HINTING ON A COOLER PATTERN
THE MIDDLE OF MARCH...THE LATEST EC/GFS IS CONSIDERING A MORE
ZONAL FLOW BY LATE NEXT WEEK. THIS WOULD LEAN TOWARD A MORE
MODERATING TREND...AND NOT SO COLD. ..JLT..
&&
.AVIATION.../18Z TAF ISSUANCE/
MAIN ISSUE THIS TAF PERIOD IS WHAT WILL HAPPEN WITH EXPANSIVE
STRATUS DECK IN PLACE. SFC RIDGE AXIS IS CURRENTLY FROM NEAR SIOUX
FALLS TO BISMARK...WITH CONDS MAINLY VFR WEST OF THIS AXIS. THE
RIDGE WILL SLIDE ACROSS THE MPX AREA TONIGHT...WHICH WOULD IMPLY
SKIES SHOULD CLEAR OUT FROM WEST TO EAST...BUT THIS IS LOOKING
LIKE A SCENARIO WHERE LOW LEVEL MOISTURE GETS TRAPPED BENEATH THE
INVERSION AND IT TAKES A NEW ROUND OF SOLAR MIXING THURSDAY
MORNING TO FINALLY BLAST THE LOW CLOUDS OUT. THIS IS THE SCENARIO
THE HRRR PLAYS OUT AND IN GENERAL WHAT WAS FOLLOWED FOR THESE TAFS.
ONE THING TO WATCH CLOSELY THOUGH THIS AFTERNOON IS WHAT HAPPENS
TO THE HOLE IN STRATUS OVER WRN WI...IF THIS CAN EXPAND SOME THIS
AFTERNOON...THEN THERE IS A GOOD CHANCE THAT SKIES WILL STAY CLEAR
ACROSS ERN TERMINALS. IF THIS HAPPENS...THEN RNH/EAU WILL LIKELY
HAVE TO WORRY ABOUT FOG IN THE MORNING.
KMSP...CONFIDENCE IN OPTIMISTIC SKY FORECAST THIS EVENING IS LOW.
GOING VFR AT 4Z WILL WORK OUT...SO LONG AS THE CLEARING TO THE
EAST CAN EXPAND AND SUSTAIN ITSELF. HOWEVER...COULD VERY WELL SEE
THIS NOT HAPPENING...WITH CIGS REMAINING BETWEEN 020 AND 025 UNTIL
AFTER 12Z THU...WITH THE POTENTIAL FOR GOING BELOW 017 LATE
TONIGHT. FOR WIND DIRECTION...THE SWITCH TOWARD THE SE WILL
HAPPEN OVERNIGHT. WITH SPEEDS UNDER 7 KTS...SHOULD GIVE SOME LEE
WAY IN RUNWAY CONFIG. BY THU MORNING THOUGH...BOTH NAM/GFS SHOW SE
WINDS INCREASING IN INTENSITY...SO WILL MOST LIKELY HAVE TO START
TOMORROW ON THE 12S.
/OUTLOOK FOR KMSP/
FRI...VFR. MVFR CIGS WITH CHANCE OF FZRA/RA LATE FRI NIGHT. SE
WIND 5-10 KTS.
SAT...IFR OR LOWER WITH CHANCE OF FZRA/RA. WINDS E 5 KTS.
SUN...MVFR WITH CHANCE OF -SN EARLY. WINDS N 10-15 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
JLT/MPG
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1054 AM CST WED MAR 6 2013
.SHORT TERM...(THROUGH LATE THIS AFTERNOON)
ISSUED AT 332 AM CST WED MAR 6 2013
STILL SEEING SOME WEAK BANDING ON RADAR THIS MORNING THAT IS
CORRESPONDING WITH THE FLURRIES BEING REPORTED IN THE SURFACE
OBSERVATIONS. THIS BANDING LOOKS TO BE SET UP UNDER THE CHANNELED
VORT MAX ON THE WESTERN SIDE OF THE VORT. RAP DEPICTS THAT THIS
VORT WILL MOVE EAST OF THE AREA BY LATE MORNING...SO WILL MAINTAIN
SCT FLURRIES OVER THE EASTERN HALF OF THE CWA THROUGH MID MORNING.
SATELLITE STILL SHOWS EXTENSIVE CLOUDINESS OVER MO/IL EARLY THIS
MORNING...WITH THE BACK EDGE OF THE CLOUDINESS MOVING A BIT TO THE
WEST OVER WESTERN MO/EASTERN KS THE PAST FEW HOURS. THERE HAS BEEN
SOME BREAKS SEEN OVER EASTERN IA WHICH IS COMPLICATING THE CLOUD
FORECAST...THOUGH THESE BREAKS MAY FILL BACK IN DURING THE DAY AS
MOIST LOW LEVEL CYCLONIC FLOW REMAINS OVER THE AREA. IT WILL TAKE
MOST OF THE DAY BEFORE THE LOW LEVEL RIDGE CAN MOVE EAST INTO THE
AREA...SO INCREASED CLOUD COVER FOR THE DAY. CONSEQUENTLY...DO NOT
EXPECT MUCH OF A TEMPERATURE RECOVERY GIVEN THE CLOUDS AND
NORTHWESTERLY FLOW OFF THE LINGERING SNOW PACK.
BRITT
&&
.LONG TERM...(TONIGHT THROUGH TUESDAY)
ISSUED AT 332 AM CST WED MAR 6 2013
UNSEASONABLY COLD WEATHER IS EXPECTED TGT WITH GOOD RADIATIONAL
COOLING AS THE SKY SHOULD CLEAR OUT AND THE SFC WIND SHOULD BECOME
LIGHT AS THE SFC RIDGE AXIS WILL BE RIGHT OVER THE FORECAST AREA
BY 12Z THU. SFC DEW POINTS WILL ALSO BE QUITE LOW IN THE UPPER
TEENS TO LOWER 20S...PLUS PARTS OF NERN AND CNTRL MO AND W CNTRL
IL WILL STILL HAVE SNOW COVER. A WARMING TREND WILL BEGIN ON THU
AS AN UPPER LEVEL RIDGE OVER THE PLAINS MOVES EWD TO OVER MO BY
00Z FRI...AND THE SFC WINDS BECOME SELY OVER A PORTION OF THE
AREA AS THE SFC RIDGE MOVES EAST OF THE REGION. TEMPERATURES ON
FRI SHOULD BE AT OR ABOVE NORMAL WITH A RELATIVELY STRONG UPPER
LEVEL RIDGE OVER MO AND IL...AND SLY LOW LEVEL WINDS BRINGING
WARMER 850 MB TEMPERATURES NWD INTO OUR AREA. SHOWERS MAY MOVE
INTO PORTIONS OF NERN AND CNTRL MO AS EARLY AS SAT AS A SLY LOW
LEVEL JET BRINGS INCREASING LOW LEVEL WAA AND MOISTURE INTO THIS
AREA WELL AHEAD OF THE UPPER LEVEL LOW AND ASSOCIATED SFC LOW
MOVING EWD FROM THE SRN ROCKIES INTO THE SRN PLAINS. THE GFS MODEL
IS A LITTLE QUICKER WITH THIS STORM SYSTEM THAN THE ECMWF MODEL.
SHOWERS AND POSSIBLY A FEW THUNDERSTORMS SHOULD MOVE INTO MUCH OF
THE FORECAST AREA ON SAT NGT. WILL LEAN TOWARD THE SLOWER
SOLUTION OF THE ECMWF MODEL WHICH HAS ABOVE NORMAL TEMPERATURES
CONTINUING ON SUN WITH THE COLD FRONT MOVING ONLY SLOWLY SEWD
THROUGH OUR AREA AS THE UPPER LEVEL LOW REMAINS CLOSED OFF AND W OF
OUR AREA. COLDER AIR SHOULD ADVECT SEWD INTO THE REGION SUN NGT
BEHIND THE SFC LOW AND TRAILING COLD FRONT WITH THE RAIN POSSIBLY
CHANGING TO SNOW ACROSS PORTIONS OF NERN AND CNTRL MO AS WELL AS W
CNTRL IL. COLDER...BELOW NORMAL TEMPERATURES SHOULD OCCUR ON
MONDAY WITH LINGERING SNOW POSSIBLE AS THE UPPER LEVEL LOW/TROUGH
AND ASSOCIATED SFC LOW SHIFT E OF OUR AREA WITH STRONG CAA LIKELY
ON THE BACKSIDE.
GKS
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1049 AM CST WED MAR 6 2013
THE MVFR STRATUS WILL CONTINUE TO LIFT AND THIN THIS AFTERNOON AS
HIGH PRESSURE EDGES EAST INTO MISSOURI. CLEARING TREND SHOULD
CONTINUE INTO THE EVENING WITH MOSTLY CLEAR CONDITIONS OVERNIGHT
AND THURSDAY. PRESSURE GRADIENT BEGINNING TO RELAX ACROSS THE
REGION WITH NORTHWEST WIND DECREASING AND BECOMING LIGHT TONIGHT.
SPECIFICS FOR KSTL...
MVFR STRATUS WILL LIFT TO VFR THIS AFTERNOON AND THEN SCT BY
EVENING. CLEAR CONDITIONS WITH LIGHT AND VARIABLE WIND OVERNIGHT.
CVKING
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
511 AM CST WED MAR 6 2013
.SHORT TERM...(THROUGH LATE THIS AFTERNOON)
ISSUED AT 332 AM CST WED MAR 6 2013
STILL SEEING SOME WEAK BANDING ON RADAR THIS MORNING THAT IS
CORRESPONDING WITH THE FLURRIES BEING REPORTED IN THE SURFACE
OBSERVATIONS. THIS BANDING LOOKS TO BE SET UP UNDER THE CHANNELED
VORT MAX ON THE WESTERN SIDE OF THE VORT. RAP DEPICTS THAT THIS
VORT WILL MOVE EAST OF THE AREA BY LATE MORNING...SO WILL MAINTAIN
SCT FLURRIES OVER THE EASTERN HALF OF THE CWA THROUGH MID MORNING.
SATELLITE STILL SHOWS EXTENSIVE CLOUDINESS OVER MO/IL EARLY THIS
MORNING...WITH THE BACK EDGE OF THE CLOUDINESS MOVING A BIT TO THE
WEST OVER WESTERN MO/EASTERN KS THE PAST FEW HOURS. THERE HAS BEEN
SOME BREAKS SEEN OVER EASTERN IA WHICH IS COMPLICATING THE CLOUD
FORECAST...THOUGH THESE BREAKS MAY FILL BACK IN DURING THE DAY AS
MOIST LOW LEVEL CYCLONIC FLOW REMAINS OVER THE AREA. IT WILL TAKE
MOST OF THE DAY BEFORE THE LOW LEVEL RIDGE CAN MOVE EAST INTO THE
AREA...SO INCREASED CLOUD COVER FOR THE DAY. CONSEQUENTLY...DO NOT
EXPECT MUCH OF A TEMPERATURE RECOVERY GIVEN THE CLOUDS AND
NORTHWESTERLY FLOW OFF THE LINGERING SNOW PACK.
BRITT
&&
.LONG TERM...(TONIGHT THROUGH TUESDAY)
ISSUED AT 332 AM CST WED MAR 6 2013
UNSEASONABLY COLD WEATHER IS EXPECTED TGT WITH GOOD RADIATIONAL
COOLING AS THE SKY SHOULD CLEAR OUT AND THE SFC WIND SHOULD BECOME
LIGHT AS THE SFC RIDGE AXIS WILL BE RIGHT OVER THE FORECAST AREA
BY 12Z THU. SFC DEW POINTS WILL ALSO BE QUITE LOW IN THE UPPER
TEENS TO LOWER 20S...PLUS PARTS OF NERN AND CNTRL MO AND W CNTRL
IL WILL STILL HAVE SNOW COVER. A WARMING TREND WILL BEGIN ON THU
AS AN UPPER LEVEL RIDGE OVER THE PLAINS MOVES EWD TO OVER MO BY
00Z FRI...AND THE SFC WINDS BECOME SELY OVER A PORTION OF THE
AREA AS THE SFC RIDGE MOVES EAST OF THE REGION. TEMPERATURES ON
FRI SHOULD BE AT OR ABOVE NORMAL WITH A RELATIVELY STRONG UPPER
LEVEL RIDGE OVER MO AND IL...AND SLY LOW LEVEL WINDS BRINGING
WARMER 850 MB TEMPERATURES NWD INTO OUR AREA. SHOWERS MAY MOVE
INTO PORTIONS OF NERN AND CNTRL MO AS EARLY AS SAT AS A SLY LOW
LEVEL JET BRINGS INCREASING LOW LEVEL WAA AND MOISTURE INTO THIS
AREA WELL AHEAD OF THE UPPER LEVEL LOW AND ASSOCIATED SFC LOW
MOVING EWD FROM THE SRN ROCKIES INTO THE SRN PLAINS. THE GFS MODEL
IS A LITTLE QUICKER WITH THIS STORM SYSTEM THAN THE ECMWF MODEL.
SHOWERS AND POSSIBLY A FEW THUNDERSTORMS SHOULD MOVE INTO MUCH OF
THE FORECAST AREA ON SAT NGT. WILL LEAN TOWARD THE SLOWER
SOLUTION OF THE ECMWF MODEL WHICH HAS ABOVE NORMAL TEMPERATURES
CONTINUING ON SUN WITH THE COLD FRONT MOVING ONLY SLOWLY SEWD
THROUGH OUR AREA AS THE UPPER LEVEL LOW REMAINS CLOSED OFF AND W OF
OUR AREA. COLDER AIR SHOULD ADVECT SEWD INTO THE REGION SUN NGT
BEHIND THE SFC LOW AND TRAILING COLD FRONT WITH THE RAIN POSSIBLY
CHANGING TO SNOW ACROSS PORTIONS OF NERN AND CNTRL MO AS WELL AS W
CNTRL IL. COLDER...BELOW NORMAL TEMPERATURES SHOULD OCCUR ON
MONDAY WITH LINGERING SNOW POSSIBLE AS THE UPPER LEVEL LOW/TROUGH
AND ASSOCIATED SFC LOW SHIFT E OF OUR AREA WITH STRONG CAA LIKELY
ON THE BACKSIDE.
GKS
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 510 AM CST WED MAR 6 2013
LARGE AREA OF CLOUDS STILL COVERS MOST OF MO/IL...THOUGH THERE IS
A LARGE BREAK THAT HAS DEVELOPED THE PAST FEW HOURS OVER SOUTHEAST
IA/NORTHERN IL. THIS IS TIMED TO REACH KUIN AROUND 12Z AND THE ST.
METRO TAF SITES AROUND 15Z. LOW LEVELS OF THE ATMOSPHERE REMAIN
VERY MOIST...SO THINK THAT THIS HOLE WILL LIKELY FILL BACK IN...SO
HAVE STAYED WITH PREDOMINANT CEILINGS OF 020-030 WITH TEMPO GROUPS
REFLECTING THE VFR CONDITIONS. WHILE IT WILL LIKELY TAKE UNTIL
LATE AFTERNOON/EVENING BEFORE THE CLOUDS CLEAR OUT OF THE AREA...
SHOULD SEE CIGS CLIMB ABOVE 3000FT BY EARLY AFTERNOON.
NORTHWEST WINDS WILL GUST INTO THE 25KT RANGE EARLY THIS MORNING...
BUT WILL THEN DECREASE THROUGH THE DAY AS A LOW LEVEL RIDGE MOVES
INTO THE AREA FROM THE WEST. THERE IS SOME POTENTIAL THAT SOME FOG
MAY DEVELOP WITHIN THE RIDGE AXIS LATE TONIGHT...PARTICULARLY AT
KCOU WHERE SOME SNOW REMAINS ON THE GROUND. CONFIDENCE IS NOT HIGH
ENOUGH TO INCLUDE IT IN THIS TAF ISSUANCE.
SPECIFICS FOR KSTL...AREA OF CLEARING OVER SOUTHEAST IA/WEST
CENTRAL IL IS TIMED TO REACH THE TERMINAL AROUND 15Z. STILL THINK
THAT LOW LEVELS OF THE ATMOSPHERE ARE MOIST ENOUGH FOR THE AREA OF
CLEARING TO FILL BACK IN THIS MORNING...SO ONLY USED A TEMPO GROUP
TO REFLECT IT. CEILINGS WILL LIKELY INCREASE TO VFR BY THIS
AFTERNOON. WINDS WILL SLOWLY DECREASE TODAY BEFORE BECOMING LIGHT
TONIGHT AS A LOW LEVEL RIDGE AXIS MOVES ACROSS THE AREA.
BRITT
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
345 AM CST WED MAR 6 2013
.SHORT TERM...(THROUGH LATE THIS AFTERNOON)
ISSUED AT 332 AM CST WED MAR 6 2013
STILL SEEING SOME WEAK BANDING ON RADAR THIS MORNING THAT IS
CORRESPONDING WITH THE FLURRIES BEING REPORTED IN THE SURFACE
OBSERVATIONS. THIS BANDING LOOKS TO BE SET UP UNDER THE CHANNELED
VORT MAX ON THE WESTERN SIDE OF THE VORT. RAP DEPICTS THAT THIS
VORT WILL MOVE EAST OF THE AREA BY LATE MORNING...SO WILL MAINTAIN
SCT FLURRIES OVER THE EASTERN HALF OF THE CWA THROUGH MID MORNING.
SATELLITE STILL SHOWS EXTENSIVE CLOUDINESS OVER MO/IL EARLY THIS
MORNING...WITH THE BACK EDGE OF THE CLOUDINESS MOVING A BIT TO THE
WEST OVER WESTERN MO/EASTERN KS THE PAST FEW HOURS. THERE HAS BEEN
SOME BREAKS SEEN OVER EASTERN IA WHICH IS COMPLICATING THE CLOUD
FORECAST...THOUGH THESE BREAKS MAY FILL BACK IN DURING THE DAY AS
MOIST LOW LEVEL CYCLONIC FLOW REMAINS OVER THE AREA. IT WILL TAKE
MOST OF THE DAY BEFORE THE LOW LEVEL RIDGE CAN MOVE EAST INTO THE
AREA...SO INCREASED CLOUD COVER FOR THE DAY. CONSEQUENTLY...DO NOT
EXPECT MUCH OF A TEMPERATURE RECOVERY GIVEN THE CLOUDS AND
NORTHWESTERLY FLOW OFF THE LINGERING SNOW PACK.
BRITT
&&
.LONG TERM...(TONIGHT THROUGH TUESDAY)
ISSUED AT 332 AM CST WED MAR 6 2013
UNSEASONABLY COLD WEATHER IS EXPECTED TGT WITH GOOD RADIATIONAL
COOLING AS THE SKY SHOULD CLEAR OUT AND THE SFC WIND SHOULD BECOME
LIGHT AS THE SFC RIDGE AXIS WILL BE RIGHT OVER THE FORECAST AREA
BY 12Z THU. SFC DEW POINTS WILL ALSO BE QUITE LOW IN THE UPPER
TEENS TO LOWER 20S...PLUS PARTS OF NERN AND CNTRL MO AND W CNTRL
IL WILL STILL HAVE SNOW COVER. A WARMING TREND WILL BEGIN ON THU
AS AN UPPER LEVEL RIDGE OVER THE PLAINS MOVES EWD TO OVER MO BY
00Z FRI...AND THE SFC WINDS BECOME SELY OVER A PORTION OF THE
AREA AS THE SFC RIDGE MOVES EAST OF THE REGION. TEMPERATURES ON
FRI SHOULD BE AT OR ABOVE NORMAL WITH A RELATIVELY STRONG UPPER
LEVEL RIDGE OVER MO AND IL...AND SLY LOW LEVEL WINDS BRINGING
WARMER 850 MB TEMPERATURES NWD INTO OUR AREA. SHOWERS MAY MOVE
INTO PORTIONS OF NERN AND CNTRL MO AS EARLY AS SAT AS A SLY LOW
LEVEL JET BRINGS INCREASING LOW LEVEL WAA AND MOISTURE INTO THIS
AREA WELL AHEAD OF THE UPPER LEVEL LOW AND ASSOCIATED SFC LOW
MOVING EWD FROM THE SRN ROCKIES INTO THE SRN PLAINS. THE GFS MODEL
IS A LITTLE QUICKER WITH THIS STORM SYSTEM THAN THE ECMWF MODEL.
SHOWERS AND POSSIBLY A FEW THUNDERSTORMS SHOULD MOVE INTO MUCH OF
THE FORECAST AREA ON SAT NGT. WILL LEAN TOWARD THE SLOWER
SOLUTION OF THE ECMWF MODEL WHICH HAS ABOVE NORMAL TEMPERATURES
CONTINUING ON SUN WITH THE COLD FRONT MOVING ONLY SLOWLY SEWD
THROUGH OUR AREA AS THE UPPER LEVEL LOW REMAINS CLOSED OFF AND W OF
OUR AREA. COLDER AIR SHOULD ADVECT SEWD INTO THE REGION SUN NGT
BEHIND THE SFC LOW AND TRAILING COLD FRONT WITH THE RAIN POSSIBLY
CHANGING TO SNOW ACROSS PORTIONS OF NERN AND CNTRL MO AS WELL AS W
CNTRL IL. COLDER...BELOW NORMAL TEMPERATURES SHOULD OCCUR ON
MONDAY WITH LINGERING SNOW POSSIBLE AS THE UPPER LEVEL LOW/TROUGH
AND ASSOCIATED SFC LOW SHIFT E OF OUR AREA WITH STRONG CAA LIKELY
ON THE BACKSIDE.
GKS
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1150 PM CST TUE MAR 5 2013
ABUNDANT HI-END MVFR/LO-END VFR CIGS COVERING THE ENTIRE BI-STATE
REGION AND SHOW NO SIGN OF ABATEMENT. SOME BREAKS HAVE DEVELOPED
WAY UPSTREAM IN NERN IA AND MN...BUT WILL TAKE QUITE SOME TIME TO
WORK DOWN INTO OUR AREA AND CLOUDS HAVE SHOWN SIGNS OF ATTEMPTING
TO FILL THESE BREAKS OVER THE PAST COUPLE HOURS...SO FOR NOW WILL
KEEP LO CIGS GOING CENTERED AROUND 3KFT. THESE CLOUDS SHOULD STICK
WITH US THRU MUCH OF THE DAY ON WEDNESDAY BEFORE FINALLY BREAKING
UP OR MOVING OFF TO THE E WITH ADVANCE OF SFC RIDGE WEDNESDAY
EVENING. LAST GASP OF SNOW MOVING THRU STL METRO AND APPEARS IT
MAY BE WITH US FOR A FEW MORE HOURS SO HAVE EXTENDED MENTION THRU
09Z. OTHERWISE...NW GUSTY SFC WINDS WILL ALSO SLOWLY DIMINISH BUT
MAY NOT GET COMPLETELY LOST UNTIL LATE WEDNESDAY MORNING.
SPECIFICS FOR KSTL...CIGS CENTERED AROUND 3KFT WILL BE THE RULE
THRU WEDNESDAY AFTERNOON BEFORE BREAKING UP OR MOVING OFF TO THE E
EARLY WEDNESDAY EVENING...VSBY DROPS FROM SNOW SHOULD BE MINIMAL
FROM HERE ON OUT AND ONLY HAVE TO 5SM IN TAF THRU 09Z...NW GUSTY
SFC WNDS WILL DIMINISH LATE.
TES
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1150 PM CST TUE MAR 5 2013
.UPDATE...
ISSUED AT 640 PM CST TUE MAR 5 2013
THE GOING FORECAST LOOKS TO BE GENERALLY ON TRACK. HAVE MADE A FEW
UPDATES TO BUMP POPS UP THIS EVENING AS THE BAND OF SNOW CURRENTLY
JUST SOUTH OF THE STL METRO. OTHER THAN THAT...HAVE ADDED IN
CHANCE FOR FLURRIES EVERYWHERE FOR THE OVERNIGHT AS THE RUC KEEPS
AN ELONGATED BAND OF VORTICITY OVER THE AREA AND LITTLE POCKETS OF
FRONTOGENESIS. EXPLICIT MODELS ALSO SHOW SOME LIGHT PRECIPITATION
CONTINUING TO ROTATE AROUND THE UPPER SYSTEM AS WELL.
CARNEY
&&
.SHORT TERM...(THROUGH LATE TONIGHT)
ISSUED AT 322 PM CST TUE MAR 5 2013
WITH LITTLE IN THE WAY OF ADDITIONAL SN EXPECTED THRU
TONIGHT...WILL CANCEL THE ADVISORY SOON.
AREA OF SN MOVING INTO NWRN PORTIONS OF THE CWA JUST AHEAD OF THE
UPPER LOW. THIS SN WILL CONTINUE TO MOVE SEWD INTO THE EVENING
HOURS. AN ADDITIONAL HALF INCH...MAYBE UP TO AN INCH...CAN BE
EXPECTED. WITH CLOUDS EXPECTED TO PERSIST THRU TONIGHT...HAVE
TEMPS LOWER SLIGHTLY OVERNIGHT.
WINDS WILL CONTINUE TO BE STRONG WITH GUSTS IN THE 20 TO 30 KT
RANGE INTO THE EVE. CAN NOT RULE OUT A COUPLE OF SITES BRIEFLY
REACHING WIND ADV CRITERIA...BUT EXPECT WINDS TO STAY BELOW
CRITERIA.
&&
.LONG TERM...(WEDNESDAY THROUGH NEXT TUESDAY)
ISSUED AT 240 PM CST TUE MAR 5 2013
(WEDNESDAY THROUGH THURSDAY)
CYCLONIC FLOW WILL CONTINUE ACROSS THE REGION THROUGH MIDDAY
WEDNESDAY IN THE WAKE OF THE DEPARTING SYSTEM. BELIEVE THERE WILL
BE QUITE A BIT OF RESIDUAL STRATUS AT DAYBREAK...AND WHILE THIS
WILL CLEAR/DECREASE SOUTHEASTWARD DURING THE MORNING/EARLY
AFTERNOON...THERE WILL ALSO BE A TENDENCY FOR ADDITIONAL STRATOCU
TO DEVELOP WITH HEATING. WITH THIS IN MIND I HAVE SHADED MY
TEMPERATURES TOWARDS THE COOLER MET GUIDANCE. IT WILL ALSO REMAIN
BREEZY ACROSS FAR EASTERN MO INTO WESTERN ILLINOIS THROUGH THE
EARLY AFTERNOON...THEN WINDS SHOULD DIMINISH AS SURFACE HIGH
PRESSURE SETTLES INTO THE AREA. THE SURFACE HIGH/RIDGE WILL
DOMINATE THE AREA ON WEDNESDAY NIGHT LEADING TO SEASONABLY COLD
CONDITIONS. WE BEGIN THE TEMPERATURE MODERATION ON THURSDAY AS THE
SURFACE HIGH SLOWLY RETREATS TO THE EAST AND HEIGHTS ALOFT
RISE...HOWEVER HIGHS WILL STILL REMAIN BELOW AVERAGE.
(FRIDAY INTO TUESDAY)
THE WARM-UP SHOULD CONTINUE TO UNFOLD ON FRIDAY AND INTO THE
WEEKEND AS THE UPPER AIR PATTERN CONTINUES TO AMPLIFY AND THE
UPPER RIDGE BUILDS THROUGH THE MS VALLEY AND SHIFTS EASTWARD.
THERE IS BETTER AGREEMENT IN THE EVOLVING PATTERN AND HANDLING OF
THE WESTERN UPPER LOW/TROF WITH THE 12Z NWP SUITE THAN THE 00Z
GUIDANCE. THE GENERAL CONSENSUS NOW IS THE INCREASINGLY POSITIVELY
TILTED UPPER TROF WILL SHIFT INTO THE NATIONS MIDSECTION BY SUNDAY
WITH THE UPPER LOW EJECTING NEWD THROUGH THE MID MS VALLEY SUNDAY
NIGHT INTO EARLY MONDAY. THIS SHOULD BRING A GOOD RAIN THREAT TO
THE REGION LATE SATURDAY NIGHT INTO SUNDAY NIGHT. THERE ARE NOW
SOME SUGGESTIONS THAT THERE COULD BE A CHANGEOVER FROM RAIN TO
SNOW ACROSS PARTS OF NORTHERN MISSOURI LATE SUNDAY NIGHT AND
POSSIBLY POTENTIAL FOR SOME LIGHT ACCUMULATIONS...HOWEVER THE
MODELS HAVE BEEN QUITE CHAOTIC WITH THE DETAILS OF THIS SYSTEM AND
THUS CONFIDENCE IS LOW ON THIS ASPECT OF THE SYSTEM.
GLASS
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1150 PM CST TUE MAR 5 2013
ABUNDANT HI-END MVFR/LO-END VFR CIGS COVERING THE ENTIRE BI-STATE
REGION AND SHOW NO SIGN OF ABATEMENT. SOME BREAKS HAVE DEVELOPED
WAY UPSTREAM IN NERN IA AND MN...BUT WILL TAKE QUITE SOME TIME TO
WORK DOWN INTO OUR AREA AND CLOUDS HAVE SHOWN SIGNS OF ATTEMPTING
TO FILL THESE BREAKS OVER THE PAST COUPLE HOURS...SO FOR NOW WILL
KEEP LO CIGS GOING CENTERED AROUND 3KFT. THESE CLOUDS SHOULD STICK
WITH US THRU MUCH OF THE DAY ON WEDNESDAY BEFORE FINALLY BREAKING
UP OR MOVING OFF TO THE E WITH ADVANCE OF SFC RIDGE WEDNESDAY
EVENING. LAST GASP OF SNOW MOVING THRU STL METRO AND APPEARS IT
MAY BE WITH US FOR A FEW MORE HOURS SO HAVE EXTENDED MENTION THRU
09Z. OTHERWISE...NW GUSTY SFC WINDS WILL ALSO SLOWLY DIMINISH BUT
MAY NOT GET COMPLETELY LOST UNTIL LATE WEDNESDAY MORNING.
SPECIFICS FOR KSTL...CIGS CENTERED AROUND 3KFT WILL BE THE RULE
THRU WEDNESDAY AFTERNOON BEFORE BREAKING UP OR MOVING OFF TO THE E
EARLY WEDNESDAY EVENING...VSBY DROPS FROM SNOW SHOULD BE MINIMAL
FROM HERE ON OUT AND ONLY HAVE TO 5SM IN TAF THRU 09Z...NW GUSTY
SFC WNDS WILL DIMINISH LATE.
TES
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS HASTINGS NE
356 PM CST WED MAR 6 2013
.SHORT TERM...(TONIGHT THROUGH THURSDAY)
ISSUED AT 353 PM CST WED MAR 6 2013
TONIGHT THROUGH MONDAY.
BIGGEST CHALLENGE WILL BE DETERMINING SKY COVER AND VISIBILITY FOR
TONIGHT INTO EARLY THURSDAY MORNING.
THE STRATUS THAT STUCK AROUND AND RETROGRADED WESTWARD INTO THE
EASTERN HALF OF THE CWA HAS LONG MIXED OUT...WITH ONLY SOME CIRRUS
MAKING ITS WAY INTO OUR CWA FROM THE SOUTH/SOUTHWEST.
SATELLITE AND WATER VAPOR REVEAL SPLIT FLOW IN UPPER
LEVELS...PLACING OUR CWA BETWEEN. THE SURFACE RIDGE CONTINUES TO
TREK EAST...WHICH WILL EVENTUALLY TURN WIND TO A MORE SE TO S/SE
WIND DIRECTION. MODELS ARE STILL KEYING IN ON SOME POSSIBLE
STRATUS/FOG IN THE WESTERN CWA OVERNIGHT AND INTO THURSDAY
MORNING...AND WITH THIS CONSISTENT SIGNAL...HAVE LEFT IN THE FOG
FROM THE PREVIOUS FORECAST AND EXPANDED THIS A LITTLE FARTHER TO THE
WEST. THE RAP IS PICKING UP SOME INCREASED STRATUS IN THE WEST AND
EVENTUALLY NORTH AS A LOW-LEVEL JET INCREASED DURING THE OVERNIGHT.
THE NMM ALSO INDICATES SOME INCREASE STRATUS OVERNIGHT...BUT OVER A
LARGER PORTION OF THE CWA. CONFIDENCE REMAINS LOW FOR SKY COVER
TONIGHT AS MODELS DO NOT HAVE A GREAT HANDLE ON LOW-LEVEL SKY COVER
AND FRANKLY...HAVE NOT DONE THAT GREAT FOR AWHILE. THE NAM
ADVERTISES SOME LIGHT QPF IN THE NORTHERN CWA...SOMEWHAT NEAR THE
NOSE OF THE MODEST LOW-LEVEL JET DEVELOPING TONIGHT. WITH SUCH A DRY
PROFILE...I DOUBT IF THERE IS MUCH CHANCE AT ALL OF MEASURABLE
PRECIPITATION...ALTHOUGH THIS COULD BE AN INDICATOR OF SOME
DEVELOPING STRATUS...WHICH SEEMS TO BE SUPPORTED BY THE
USING RECENT VERIFICATION STATISTICS...I MADE SOME MINOR CHANGES
TO TEMPERATURES FOR TONIGHT AND THURSDAY...WITH THE REMAINING
SNOWPACK IN THE WESTERN CWA STILL HAVING SOME INFLUENCE WITH HIGH
TEMPERATURES THURSDAY. THIS SNOWPACK MAY HAVE LIMITED EFFECT ON THE
VISIBILITY FOR OVERNIGHT TONIGHT INTO THURSDAY MORNING AS WELL.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 353 PM CST WED MAR 6 2013
THURSDAY NIGHT THROUGH WEDNESDAY. MAIN FORECAST
CONCERNS ARE PRECIPITATION FRIDAY NIGHT THROUGH SUNDAY NIGHT AND
TEMPERATURES THROUGH THE PERIOD.
AN UPPER LEVEL RIDGE WILL MOVE THROUGH THE AREA THURSDAY NIGHT INTO
FRIDAY. THERE IS WARM ADVECTION ACROSS THE AREA AND TEMPERATURES
SHOULD BE WARMER. IN ADDITION...THE SOUTH WINDS INCREASE THE
MOISTURE ACROSS THE AREA AND CLOUDS WILL INCREASE. A COUPLE OF THE
MODELS HAVE STARTED SHOWING SOME LIGHT QPF ASSOCIATED WITH THE WARM
ADVECTION. HAVE KEPT THE FORECAST DRY FOR NOW AND WILL WAIT FOR
FURTHER RUNS.
BY FRIDAY NIGHT AN UPPER LEVEL LOW PRESSURE SYSTEM MOVING OUT OF THE
ROCKIES WILL START TO AFFECT THE AREA. PRECIPITATION SPREADS ACROSS
THE AREA. WARM TEMPERATURES WILL KEEP PRECIPITATION IN THE FORM OF
RAIN. THERE IS SOME WEAK INSTABILITY WITH MUCAPE UP TO 500 J/KG
ACROSS THE AREA. THERE COULD BE SOME ISOLATED THUNDERSTORMS FRIDAY
NIGHT INTO SATURDAY. SATURDAY WILL CONTINUE TO BE WARM AHEAD OF THE
SURFACE LOW WITH SOUTHERLY WINDS.
THE MODELS HAVE COME INTO BETTER AGREEMENT WITH THE TRACK OF THE
UPPER LOW AS IT MOVES THROUGH THE PLAINS. AS THE UPPER LOW MOVES
THROUGH THE PLAINS THE COLDER AIR MOVES INTO THE AREA FROM THE WEST.
SATURDAY NIGHT THE PRECIPITATION CHANGES FROM RAIN TO SNOW IN THE
WEST DURING THE EVENING THEN THE SNOW SPREADS ACROSS THE AREA DURING
NIGHT. BY MORNING EXPECT SNOW IN THE NORTHWEST WITH RAIN AND SNOW
FURTHER SOUTHEAST. ON SUNDAY SNOW WILL BE FOUND ACROSS MUCH OF THE
AREA WITH SOME RAIN OR SNOW POSSIBLE IN THE SOUTHEAST. THE UPPER LOW
WILL SLIDE TO THE EAST SUNDAY NIGHT AND PRECIPITATION WILL COME TO
AN END. PRECIPITATION AMOUNTS ARE NOT VERY HIGH AND EXPECT SOME SNOW
ACCUMULATIONS. SUNDAY WILL BE COLDER WITH HIGHS ONLY IN THE 30S
BEHIND THE COLD FRONT.
THE UPPER LOW WILL BE TO THE EAST AND THERE WILL BE NORTHWEST FLOW
ACROSS THE AREA MONDAY THROUGH WEDNESDAY. THERE COULD BE SOME CLOUDS
AS A FEW WEAK UPPER LEVEL WAVES MOVE THROUGH THE AREA...BUT THERE IS
WARM ADVECTION AND TEMPERATURES SHOULD START TO WARM UP. DEPENDING
ON HOW MUCH SNOW THERE IS SATURDAY NIGHT INTO SUNDAY THE
TEMPERATURES MAY REMAIN A LITTLE COOLER FOR MONDAY...BUT WARM FOR
TUESDAY AND WEDNESDAY.
&&
.AVIATION...(FOR THE 18Z TAF THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1159 AM CST WED MAR 6 2013
STRATUS TO THE WEST HAS HALTED THE EASTWARD PROGRESSION AND HAS
BEGUN TO ERODE. IT APPEARS THAT CEILINGS SHOULD BE VFR AND THAT
ANY ADDITIONAL CEILINGS SHOULD BE LIMITED TO LOCATIONS TO THE WEST
FOR THE OVERNIGHT. AS FOR LLWS...IT APPEARS LESS LIKELY THAT THIS
WILL BE AN ISSUE. SURFACE WIND SPEEDS SHOULD STAY UP A BIT TONIGHT
AS THE LOW-LEVEL JET DEVELOPS...AND WINDS ALOFT DO NOT APPEAR TO
BE QUITE AS STRONG AS ONCE SUSPECTED.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...HEINLEIN
LONG TERM...JCB
AVIATION...HEINLEIN
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1210 PM CST WED MAR 6 2013
.AVIATION...
18Z TAFS FOR KOFK...KOMA AND KLNK.
AREA OF LOW CLOUDS ACROSS EASTERN NEBRASKA HAD DECREASED
RAPIDLY DURING THE LATE MORNING AND THIS TREND IS EXPECTED TO
CONTINUE EARLY IN THE PERIOD THIS AFTERNOON. BIG QUESTION WILL BE
WHETHER CLOUDS ROLL BACK IN AGAIN THIS EVENING SIMILAR TO LAST
NIGHT. MAY BE SOME POTENTIAL IN EASTERN AREAS ALONG THE MISSOURI
RIVER WHERE MORE EXTENSIVE CLOUDS IN PLACE ACROSS WESTERN IOWA BUT
WILL KEEP VFR CONDITIONS AT ALL THREE SITES FOR NOW AND SEE HOW
THINGS DEVELOP DURING THE AFTERNOON.
&&
.PREV DISCUSSION... /ISSUED 354 AM CST WED MAR 6 2013/
DISCUSSION...
MAIN FORECAST CONCERN TODAY WILL BE THE EXTENT OF LOW CLOUDS AND
THE RESULTING AFFECT ON TEMPERATURES. THEN FOCUS TURNS TO SYSTEM
MOVING INTO THE PLAINS FOR THE WEEKEND.
AN EXPANSIVE AREA OF STRATUS CONTINUES TO MOVES SOUTH FROM THE
EASTERN DAKOTAS AND CURRENTLY COVERS MOST OF THE CWA EXCEPT THE
EXTREME WESTERN COUNTIES. THE RAP SEEMS TO HAVE THE BEST HANDLE
ON THESE CLOUDS AND WILL JUMP ON BOARD WITH THIS
GUIDANCE...KEEPING CLOUD COVER THROUGH AT LEAST 18Z OVER A
MAJORITY OF THE CWA. A SFC HIGH PRESSURE RIDGE CURRENTLY OVER
CENTRAL NEBRASKA WILL CONTINUE TO BUILD EAST AND INHIBIT MIXING
TO SCOUR OUT CLOUDS. THEREFORE THE RAP IDEA OF HANGING ONTO THE
CLOUDS SEEMS FAIR THROUGH MUCH OF THE MORNING HOURS AND POSSIBLY
INTO THE AFTERNOON IN OUR EAST. AS SOUTHERLY LOW LEVEL FLOW
INCREASES LATE THIS AFTERNOON...EXPECT CLOUDS TO MOVE OUT FROM
WEST TO EAST. HAVE REDUCED HIGHS TO A FEW DEGREES BELOW MOS DUE TO
CLOUD COVER.
QUIET CONDITIONS AND A GRADUAL WARMING TREND ARE EXPECTED TODAY
THROUGH FRIDAY AS AN UPPER RIDGE PASSES OVER THE CENTRAL CONUS
THROUGH THIS TIME PERIOD. HIGH TEMPS SHOULD BE IN THE UPPER 40S
AND LOWER 50S BY FRIDAY.
FOCUS TURNS TO LARGE SYSTEM CURRENTLY OFF THE PACIFIC NORTHWEST
COAST. THIS IS FORECAST TO ROUND THE FOUR CORNERS REGION BY
SATURDAY 12Z. MODELS CONTINUE TO COME INTO BETTER AGREEMENT ON
PLACEMENT AND TIMING LEADING TO INCREASING FORECASTER CONFIDENCE.
A LEAD SHORTWAVE WILL EJECT INTO THE CENTRAL PLAINS BY FRIDAY
NIGHT WITH A SFC WARM FRONT EXTENDING NORTHEAST AND BISECTING OUR
CWA. THIS BOUNDARY SHOULD BE THE FOCUS FOR PRECIPITATION FRIDAY
NIGHT INTO SATURDAY. BETTER UPPER LEVEL DYNAMICS WILL ADVANCE
INTO THE AREA SATURDAY NIGHT INTO SUNDAY AS THE UPPER LOW KICKS
OUT OF EASTERN COLORADO AND INTO KANSAS. WILL CONTINUE LIKELY POPS
FOR THIS TIME PERIOD. TIGHT BAROCLINIC ZONE WILL REMAIN EXTENDED
ACROSS THE FORECAST AREA WITH SNOW MOST LIKELY TO THE NORTH OF THE
BOUNDARY AND RAIN IN THE SOUTH...WITH A TRANSITION ZONE SOMEWHERE
IN THE MIDDLE. MODELS HAVE BEEN CONSISTENT WITH DROPPING COLDER
AIR SOUTH OVER THE FORECAST AREA SO SNOW COULD BE PRIMARY PCPN
TYPE SAT NIGHT THROUGH SUNDAY NIGHT WHEN DEFORMATION ZONE MOVES
OVERHEAD. HAVE INCREASED THE SFC WINDS ON THE BACKSIDE OF THIS
SYSTEM SATURDAY NIGHT THROUGH SUNDAY NIGHT WITH UNIDIRECTIONAL
NORTHERLY FLOW CREATING QUITE BLUSTERY CONDITIONS. 850MB WIND
SPEEDS ARE FORECAST AROUND 50 KTS OFF BOTH THE 00Z GFS AND 00Z
ECMWF. THIS SAID...IF ANY SNOW IS FALLING...IT WILL BE BLOWING
AROUND.
THIS SYSTEM QUICKLY MOVES EAST SUNDAY NIGHT ENDING PCPN FROM WEST
TO EAST LEAVING NORTHWESTERLY FLOW ALOFT. FORECAST SUB ZERO C 850
MB TEMPS IN ADDITION TO POTENTIAL SNOW COVER WOULD SUGGEST BELOW
NORMAL TEMPS EARLY NEXT WEEK.
KERN
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
FOBERT
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
554 AM CST WED MAR 6 2013
.AVIATION...
12Z TAFS FOR KOFK...KOMA AND KLNK.
LOW CLOUDS CONTINUED TO HANG TOUGH ACROSS EASTERN NEBRASKA WITH
CIGS RANGING FROM JUST BELOW 1K FT AGL ON NW EDGE TO NEAR 2K FT
AGL ON SERN END. ALTHOUGH WIND FLOW IS WEAK AND FAVORABLE FOR A
CONTINUATION OF CIGS THROUGH MIDDAY AT LEAST...BREAKS IN OVERCAST
HAVE BEEN NOTED OVR WRN IA AND NW MO WHICH LEADS TO A LOW
CONFIDENCE CLOUD FORECAST. WOULD SUSPECT...HOWEVER...THAT EROSION
WILL CONTINUE OR EVEN ACCELERATE AS DAYTIME HEATING COMMENCES
LATER THIS MORNING. SOME REDEVELOPMENT POSSIBLE AGAIN LATER
TONIGHT...ESPECIALLY AT KOFK...BUT FOR NOW KEPT CIGS OUT OF
FORECAST FOR TONIGHT.
CHERMOK
&&
.PREV DISCUSSION... /ISSUED 354 AM CST WED MAR 6 2013/
DISCUSSION...
MAIN FORECAST CONCERN TODAY WILL BE THE EXTENT OF LOW CLOUDS AND
THE RESULTING AFFECT ON TEMPERATURES. THEN FOCUS TURNS TO SYSTEM
MOVING INTO THE PLAINS FOR THE WEEKEND.
AN EXPANSIVE AREA OF STRATUS CONTINUES TO MOVES SOUTH FROM THE
EASTERN DAKOTAS AND CURRENTLY COVERS MOST OF THE CWA EXCEPT THE
EXTREME WESTERN COUNTIES. THE RAP SEEMS TO HAVE THE BEST HANDLE
ON THESE CLOUDS AND WILL JUMP ON BOARD WITH THIS
GUIDANCE...KEEPING CLOUD COVER THROUGH AT LEAST 18Z OVER A
MAJORITY OF THE CWA. A SFC HIGH PRESSURE RIDGE CURRENTLY OVER
CENTRAL NEBRASKA WILL CONTINUE TO BUILD EAST AND INHIBIT MIXING
TO SCOUR OUT CLOUDS. THEREFORE THE RAP IDEA OF HANGING ONTO THE
CLOUDS SEEMS FAIR THROUGH MUCH OF THE MORNING HOURS AND POSSIBLY
INTO THE AFTERNOON IN OUR EAST. AS SOUTHERLY LOW LEVEL FLOW
INCREASES LATE THIS AFTERNOON...EXPECT CLOUDS TO MOVE OUT FROM
WEST TO EAST. HAVE REDUCED HIGHS TO A FEW DEGREES BELOW MOS DUE TO
CLOUD COVER.
QUIET CONDITIONS AND A GRADUAL WARMING TREND ARE EXPECTED TODAY
THROUGH FRIDAY AS AN UPPER RIDGE PASSES OVER THE CENTRAL CONUS
THROUGH THIS TIME PERIOD. HIGH TEMPS SHOULD BE IN THE UPPER 40S
AND LOWER 50S BY FRIDAY.
FOCUS TURNS TO LARGE SYSTEM CURRENTLY OFF THE PACIFIC NORTHWEST
COAST. THIS IS FORECAST TO ROUND THE FOUR CORNERS REGION BY
SATURDAY 12Z. MODELS CONTINUE TO COME INTO BETTER AGREEMENT ON
PLACEMENT AND TIMING LEADING TO INCREASING FORECASTER CONFIDENCE.
A LEAD SHORTWAVE WILL EJECT INTO THE CENTRAL PLAINS BY FRIDAY
NIGHT WITH A SFC WARM FRONT EXTENDING NORTHEAST AND BISECTING OUR
CWA. THIS BOUNDARY SHOULD BE THE FOCUS FOR PRECIPITATION FRIDAY
NIGHT INTO SATURDAY. BETTER UPPER LEVEL DYNAMICS WILL ADVANCE
INTO THE AREA SATURDAY NIGHT INTO SUNDAY AS THE UPPER LOW KICKS
OUT OF EASTERN COLORADO AND INTO KANSAS. WILL CONTINUE LIKELY POPS
FOR THIS TIME PERIOD. TIGHT BAROCLINIC ZONE WILL REMAIN EXTENDED
ACROSS THE FORECAST AREA WITH SNOW MOST LIKELY TO THE NORTH OF THE
BOUNDARY AND RAIN IN THE SOUTH...WITH A TRANSITION ZONE SOMEWHERE
IN THE MIDDLE. MODELS HAVE BEEN CONSISTENT WITH DROPPING COLDER
AIR SOUTH OVER THE FORECAST AREA SO SNOW COULD BE PRIMARY PCPN
TYPE SAT NIGHT THROUGH SUNDAY NIGHT WHEN DEFORMATION ZONE MOVES
OVERHEAD. HAVE INCREASED THE SFC WINDS ON THE BACKSIDE OF THIS
SYSTEM SATURDAY NIGHT THROUGH SUNDAY NIGHT WITH UNIDIRECTIONAL
NORTHERLY FLOW CREATING QUITE BLUSTERY CONDITIONS. 850MB WIND
SPEEDS ARE FORECAST AROUND 50 KTS OFF BOTH THE 00Z GFS AND 00Z
ECMWF. THIS SAID...IF ANY SNOW IS FALLING...IT WILL BE BLOWING
AROUND.
THIS SYSTEM QUICKLY MOVES EAST SUNDAY NIGHT ENDING PCPN FROM WEST
TO EAST LEAVING NORTHWESTERLY FLOW ALOFT. FORECAST SUB ZERO C 850
MB TEMPS IN ADDITION TO POTENTIAL SNOW COVER WOULD SUGGEST BELOW
NORMAL TEMPS EARLY NEXT WEEK.
KERN
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
354 AM CST WED MAR 6 2013
.DISCUSSION...
MAIN FORECAST CONCERN TODAY WILL BE THE EXTENT OF LOW CLOUDS AND
THE RESULTING AFFECT ON TEMPERATURES. THEN FOCUS TURNS TO SYSTEM
MOVING INTO THE PLAINS FOR THE WEEKEND.
AN EXPANSIVE AREA OF STRATUS CONTINUES TO MOVES SOUTH FROM THE
EASTERN DAKOTAS AND CURRENTLY COVERS MOST OF THE CWA EXCEPT THE
EXTREME WESTERN COUNTIES. THE RAP SEEMS TO HAVE THE BEST HANDLE
ON THESE CLOUDS AND WILL JUMP ON BOARD WITH THIS
GUIDANCE...KEEPING CLOUD COVER THROUGH AT LEAST 18Z OVER A
MAJORITY OF THE CWA. A SFC HIGH PRESSURE RIDGE CURRENTLY OVER
CENTRAL NEBRASKA WILL CONTINUE TO BUILD EAST AND INHIBIT MIXING
TO SCOUR OUT CLOUDS. THEREFORE THE RAP IDEA OF HANGING ONTO THE
CLOUDS SEEMS FAIR THROUGH MUCH OF THE MORNING HOURS AND POSSIBLY
INTO THE AFTERNOON IN OUR EAST. AS SOUTHERLY LOW LEVEL FLOW
INCREASES LATE THIS AFTERNOON...EXPECT CLOUDS TO MOVE OUT FROM
WEST TO EAST. HAVE REDUCED HIGHS TO A FEW DEGREES BELOW MOS DUE TO
CLOUD COVER.
QUIET CONDITIONS AND A GRADUAL WARMING TREND ARE EXPECTED TODAY
THROUGH FRIDAY AS AN UPPER RIDGE PASSES OVER THE CENTRAL CONUS
THROUGH THIS TIME PERIOD. HIGH TEMPS SHOULD BE IN THE UPPER 40S
AND LOWER 50S BY FRIDAY.
FOCUS TURNS TO LARGE SYSTEM CURRENTLY OFF THE PACIFIC NORTHWEST
COAST. THIS IS FORECAST TO ROUND THE FOUR CORNERS REGION BY
SATURDAY 12Z. MODELS CONTINUE TO COME INTO BETTER AGREEMENT ON
PLACEMENT AND TIMING LEADING TO INCREASING FORECASTER CONFIDENCE.
A LEAD SHORTWAVE WILL EJECT INTO THE CENTRAL PLAINS BY FRIDAY
NIGHT WITH A SFC WARM FRONT EXTENDING NORTHEAST AND BISECTING OUR
CWA. THIS BOUNDARY SHOULD BE THE FOCUS FOR PRECIPITATION FRIDAY
NIGHT INTO SATURDAY. BETTER UPPER LEVEL DYNAMICS WILL ADVANCE
INTO THE AREA SATURDAY NIGHT INTO SUNDAY AS THE UPPER LOW KICKS
OUT OF EASTERN COLORADO AND INTO KANSAS. WILL CONTINUE LIKELY POPS
FOR THIS TIME PERIOD. TIGHT BAROCLINIC ZONE WILL REMAIN EXTENDED
ACROSS THE FORECAST AREA WITH SNOW MOST LIKELY TO THE NORTH OF THE
BOUNDARY AND RAIN IN THE SOUTH...WITH A TRANSITION ZONE SOMEWHERE
IN THE MIDDLE. MODELS HAVE BEEN CONSISTENT WITH DROPPING COLDER
AIR SOUTH OVER THE FORECAST AREA SO SNOW COULD BE PRIMARY PCPN
TYPE SAT NIGHT THROUGH SUNDAY NIGHT WHEN DEFORMATION ZONE MOVES
OVERHEAD. HAVE INCREASED THE SFC WINDS ON THE BACKSIDE OF THIS
SYSTEM SATURDAY NIGHT THROUGH SUNDAY NIGHT WITH UNIDIRECTIONAL
NORTHERLY FLOW CREATING QUITE BLUSTERY CONDITIONS. 850MB WIND
SPEEDS ARE FORECAST AROUND 50 KTS OFF BOTH THE 00Z GFS AND 00Z
ECMWF. THIS SAID...IF ANY SNOW IS FALLING...IT WILL BE BLOWING
AROUND.
THIS SYSTEM QUICKLY MOVES EAST SUNDAY NIGHT ENDING PCPN FROM WEST
TO EAST LEAVING NORTHWESTERLY FLOW ALOFT. FORECAST SUB ZERO C 850
MB TEMPS IN ADDITION TO POTENTIAL SNOW COVER WOULD SUGGEST BELOW
NORMAL TEMPS EARLY NEXT WEEK.
KERN
&&
.AVIATION...06Z TAFS FOR KOMA...KLNK AND KOFK. MVFR CEILINGS WILL
LINGER AT KOMA...PERHAPS UNTIL MID TO LATE MORNING...BUT SHOULD
BEGIN TO SCATTER OUT BY 1820Z. INITIAL CLOUD LINE WAS SLOWLY
RETREATING WEST AND FINALLY HAD REACHED KOFK...AND WILL PROBABLY
REACH KLNK BY 07-08Z. BELIEVE CLOUDS COULD SCATTER AT KOFK/KLNK BY
16-18Z.
DEWALD
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
1117 PM CST TUE MAR 5 2013
.SYNOPSIS...
ISSUED AT 320 PM CST TUE MAR 5 2013
H5 HAND ANALYSIS THIS MORNING...INDICATES A CONTINUED ACTIVE PATTERN
ACROSS NOAM. A STRONG SHORTWAVE WAS LOCATED ACROSS NWRN MISSOURI
WITH DECENT HT FALLS NOTED FROM THE TWIN CITIES SWD INTO SWRN MO.
FURTHER WEST...A LOW AMPLITUDE RIDGE EXTENDED FROM SO CALIFORNIA NWD
TO THE IDAHO PANHANDLE. WHILE WEST OF THIS FEATURE...A TROUGH
EXTENDED FROM ERN BRITISH COLUMBIA...SWD TO A CLOSED LOW OFF THE
COAST OF OREGON. ACROSS THE EASTERN CONUS...A CLOSED LOW WAS PRESENT
OVER THE CANADIAN MARITIMES WITH HIGH PRESSURE NOTED OVER NRN
QUEBEC. AT THE SURFACE...HIGH PRESSURE HAS BUILT INTO WESTERN
NEBRASKA THIS AFTERNOON RESULTING IN LIGHT WINDS. FURTHER
EAST...BREEZY CONDITIONS CONTINUED. TEMPERATURES AS OF 3 PM CST
RANGED FROM 32 AT O`NEILL TO 41 AT OGALLALA.
&&
.UPDATE...
ISSUED AT 1005 PM CST TUE MAR 5 2013
THE NEW NAM...GEM AND GFS CONTINUE TO ADVERTISE INCREASING LOW
LEVEL MOISTURE WEDNESDAY AFTERNOON AND WEDNESDAY NIGHT LEADING TO
EITHER TO THE FORMATION OF FOG OR LOW STRATUS. MEANWHILE THE RAP13
IS DRAGGING THE STRATUS ACROSS THE MISSOURI BASIN WEST TO NEAR
HIGHWAY 83 BY MORNING. IT APPEARS THE RAP IS TOO FAST. SATELLITE
TIMING TOO INDICATE IT ONLY MOVING WEST AT 5KT AND WOULD MIX OUT
DURING THE DAY AND PERHAPS RETURN WEDNESDAY NIGHT.
THE FCST FOLLOWS NAM WITH INCREASING CLOUDS AFTER MIDNIGHT AND
PATCHY FOG FORMING EAST OF HIGHWAY 61. NO DISCERNIBLE CHANGES IN
THE REST OF THE SHORT TERM FORECAST EXCEPT THE MODELS ARE SHOWING
HIGHER DEW PTS OVERNIGHT WHICH APPEARS TO BE VERIFYING.
UPDATE ISSUED AT 701 PM CST TUE MAR 5 2013
A NEW FORECAST IS OUT. RAISED OVERNIGHT LOW TEMPS A BIT IN THE
WEST WHERE A LOW LEVEL JET SHOULD KICK UP IN A FEW HOURS. LOWS
AROUND 10 TO SINGLE DIGITS EAST OF HIGHWAY 83 WHERE WINDS WILL
REMAIN CALM MOST OF THE NIGHT.
SOUTH WINDS INCREASE TO 20 TO 30 MPH WEDNESDAY AND A BLEND OF THE
NAM...GEM AND ECM INDICATED HIGHS IN THE 30S AND 40S...NO REAL
CHANGE FROM THE PREVIOUS FCST. THE NAM AND GFS SUGGEST SOME
CLOUDINESS MAY DEVELOP EAST OF HIGHWAY 83 IN THE AFTN AS RETURN
MOISTURE DEVELOPS.
EITHER FOG OR LOW CLOUDINESS DEVELOPS WEDNESDAY NIGHT WITH LOWS
IN THE 20S. SOUTH WINDS CONTINUE TO RETURN MOISTURE.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 320 PM CST TUE MAR 5 2013
TEMPERATURES THIS EVENING WILL DROP QUICKLY AS A SFC HIGH PRESSURE
MOVES ACROSS THE NORTHERN PLAINS. LIGHT WINDS...CLEAR SKIES...AND A
RELATIVELY DRY AIRMASS WILL PROVIDE FOR EFFICIENT RADIATIVE COOLING
AND LOWS IN THE LOW TO MID TEENS FOR MOST OF THE CWA. HOWEVER...AS
THE SFC HIGH SLIDES EAST OF THE AREA WINDS WILL INCREASE OUT OF THE
SOUTH FROM WEST TO EAST ACROSS THE CWA. THIS MAY ALLOW FOR WEAK
MIXING TO OCCUR LATE IN THE OVERNIGHT TOWARD EARLY TOMORROW MORNING
AND LIMIT THE PERIOD OF DIURNAL COOLING. EXPECTING OVERNIGHT LOWS TO
OCCUR EARLY BEFORE HOLDING STEADY OR EVEN WARMING A FEW DEGREES BY
DAY BREAK WEDNESDAY.
WINDS WILL CONTINUE TO INCREASE OUT OF THE SOUTH SOUTHEAST DURING
THE DAY WEDNESDAY...WITH 15 TO 25 MPH WINDS LIKELY DURING THE
AFTERNOON. CLEAR SKIES WILL CONTINUE WITH DRY AIRMASS STILL IN
PLACE. HIGH TEMPERATURES WILL BE LIMITED FOR THE EASTERN TWO-THIRDS
OF THE CWA AS 850MB TEMPS STRUGGLE TO RECOVER. EXPECTING HIGHS ONLY
IN THE 40S FOR MOST OF THE AREA...WITH 50S POSSIBLE IN THE EAST
PANHANDLE AND FAR SOUTHWEST NEBRASKA.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 320 PM CST TUE MAR 5 2013
WEDNESDAY NIGHT THROUGH FRIDAY...MAIN FORECASTING
CHALLENGE FOR THE LATTER HALF OF THE WORK WEEK DEALS WITH
TEMPERATURES...MAINLY HIGHS ON THURSDAY AND FRIDAY AS A DEEP TROUGH
OF LOW PRESSURE ALOFT DEEPENS ACROSS THE SWRN CONUS. ON THURSDAY
WARMER AIR WILL PUSH INTO THE PANHANDLE AND WESTERN AREAS WITH SRLY
WINDS DEVELOPING IN THE AFTERNOON HOURS. FURTHER EAST
HOWEVER...LIGHT SERLY AND VARIABLE WINDS IN THE CENTRAL AND EASTERN
CWA WILL LIMIT THE WARMUP TO THE UPPER 40S/LWR 50S VS. THE UPPER 50S
TO NEAR 60 OUT WEST. ON THURSDAY NIGHT...A WEAK COOL FRONT WILL PUSH
ACROSS WESTERN AND NORTH CENTRAL NEBRASKA...STALLING ACROSS NRN KS
AND SERN NEBRASKA. SURFACE LOW PRESSURE WILL DEEPEN FRIDAY ACROSS
EASTERN COLORADO...LIFTING THE FRONT NORTH INTO SOUTH CENTRAL AND
EASTERN NEBRASKA. HOWEVER...THE FRONT IS EXPECTED TO STAY OFF TO THE
SOUTH OF THE FORECAST AREA FRIDAY...LEADING TO EASTERLY UPSLOPE
WINDS AND HIGHS IN THE 40S. EVEN HIGHS IN THE 40S...MAY BE OVERLY
OPTIMISTIC.
FRIDAY NIGHT THROUGH TUESDAY...MAIN FORECASTING CHALLENGE
CONTINUES TO BE PRECIPITATION AND PRECIPITATION TYPE IN
ASSOCIATION WITH A DEEP TROUGH OF LOW PRESSURE...WHICH TRACKS
ACROSS THE CENTRAL CONUS THIS WEEKEND. THE LATEST 12Z GFS THIS
MORNING AND THE 00Z ECMWF FROM LAST NIGHT HAVE DECENT AGREEMENT
WITH THE H5 LOW POSN SATURDAY AT 12Z. AFTER THIS
POINT...DIFFERENCES WITH THE MODEL SOLUTIONS EMERGE...IN
PARTICULAR...WHETHER THE LOW PHASES WITH THE NRN STREAM OR NOT. BY
12Z SUNDAY...THE 12Z GFS FROM THIS MORNING...PHASES THE LOW WITH
THE NRN STREAM...BECOMES POSITIVELY TILTED...AND MOVES THE SYSTEM
INTO THE MID MISSISSIPPI VALLEY BY MONDAY MORNING. THE ECMWF FROM
LAST NIGHT...IS DISCONNECTED FROM THE NRN STREAM...NEUTRAL TILTED
AND REMAINS JUST OFF TO THE SOUTH OF THE CWA THROUGH 12Z MONDAY.
THE DIFFERENCES ARE HUGE IN THE AMOUNT OF QPF GENERATED BY EACH
SOLUTION THROUGH TUESDAY. FOR EXAMPLE...FOR NORTH PLATTE ACCUM QPF
RANGES ANYWHERE FROM 0.30 WITH THE 12Z GFS SOLN...TO 2.30 INCHES
WITH THE 00Z ECMWF. THE CURRENT INHERITED FORECAST...HAS THE BEST
PRECIPITATION CHANCES FROM LATE FRIDAY NIGHT THROUGH SUNDAY
MORNING AND WILL LEAVE THIS AS IS FOR NOW GIVEN THE TIMING
UNCERTAINTIES IN THE MODELS. AS FOR PRECIPITATION TYPES...MEX AND
ECE TEMPERATURES ACROSS THE SRN AND EASTERN CWA...FAVOR ALL RAIN
AT THIS JUNCTURE...WITH A MIX AND ALL SNOW IN THE WESTERN PORTION
OF THE CWA. IF THE MORE PROGRESSIVE GFS SOLUTION VERIFIES...SNOW
AMOUNTS WILL BE MUCH LIGHTER COMPARED TO THE SLOWER 00Z EC
SOLUTION. WILL TAKE A CLOSE LOOK AT THE 12Z EC SOLUTION...AND IF
IT IS PROGRESSIVE LIKE THE 12Z GFS...SOME ELIMINATION OF POPS ON
MONDAY AND TUESDAY MAY BE IN ORDER. IN ADDITION TO ELIMINATING
POPS MONDAY AND TUESDAY...IF THE MODEL COMES IN FASTER WITH THE
SYSTEM...THE THREAT FOR LARGE ACCUMULATING SNOWS AND LONG DURATION
PRECIPITATION WILL BE MINIMIZED.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1110 PM CST TUE MAR 5 2013
VFR IS EXPECTED ALL AREAS THROUGH 00Z WEDNESDAY EVENING.
THEREAFTER THE FORECAST BECOMES VERY UNCERTAIN. THE ISSUE IS RAPIDLY
INCREASING BOUNDARY LAYER MOISTURE AND THE DEVELOPMENT OF IFR CIGS
ACROSS A GOOD PORTION OF THE FCST AREA.
THE MODELS CONTINUE TO DRAG MOISTURE...CURRENTLY ACROSS THE
MISSOURI BASIN WEST TOWARD HIGHWAY 83 LATE WEDNESDAY AFTERNOON
LEADING TO THE FORMATION OF IFR WEDNESDAY NIGHT. THE RAP MODEL IS
THE FASTEST PRODUCING IFR ALONG HIGHWAY 83 BY 12Z-14Z WHILE THE
NAM...GEM AND GFS MODELS SHOW THIS FORMING AROUND 03Z WEDNESDAY
EVENING.
GIVEN THE UNCERTAINTIES OF THIS FEATURE THE BEST APPRAOCH WOULD BE
TO WAIT FOR A DEFINITIVE SATELLITE SIGNAL LATE WEDNESDAY AND THEN
MAKE THE FORECAST. SO VFR IS EXPECTED THROUGH WEDNESDAY AFTERNOON
AND PRESUMABLY...SOME SIGNAL SHOULD DEVELOP AROUND 03Z-06Z WEDNESDAY
EVENING.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...CDC
SYNOPSIS...CLB
SHORT TERM...MARTIN
LONG TERM...CLB
AVIATION...CDC
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
1014 PM CST TUE MAR 5 2013
.SYNOPSIS...
ISSUED AT 320 PM CST TUE MAR 5 2013
H5 HAND ANALYSIS THIS MORNING...INDICATES A CONTINUED ACTIVE PATTERN
ACROSS NOAM. A STRONG SHORTWAVE WAS LOCATED ACROSS NWRN MISSOURI
WITH DECENT HT FALLS NOTED FROM THE TWIN CITIES SWD INTO SWRN MO.
FURTHER WEST...A LOW AMPLITUDE RIDGE EXTENDED FROM SO CALIFORNIA NWD
TO THE IDAHO PANHANDLE. WHILE WEST OF THIS FEATURE...A TROUGH
EXTENDED FROM ERN BRITISH COLUMBIA...SWD TO A CLOSED LOW OFF THE
COAST OF OREGON. ACROSS THE EASTERN CONUS...A CLOSED LOW WAS PRESENT
OVER THE CANADIAN MARITIMES WITH HIGH PRESSURE NOTED OVER NRN
QUEBEC. AT THE SURFACE...HIGH PRESSURE HAS BUILT INTO WESTERN
NEBRASKA THIS AFTERNOON RESULTING IN LIGHT WINDS. FURTHER
EAST...BREEZY CONDITIONS CONTINUED. TEMPERATURES AS OF 3 PM CST
RANGED FROM 32 AT O`NEILL TO 41 AT OGALLALA.
&&
.UPDATE...
ISSUED AT 1005 PM CST TUE MAR 5 2013
THE NEW NAM...GEM AND GFS CONTINUE TO ADVERTISE INCREASING LOW
LEVEL MOISTURE WEDNESDAY AFTERNOON AND WEDNESDAY NIGHT LEADING TO
EITHER TO THE FORMATION OF FOG OR LOW STRATUS. MEANWHILE THE RAP13
IS DRAGGING THE STRATUS ACROSS THE MISSOURI BASIN WEST TO NEAR
HIGHWAY 83 BY MORNING. IT APPEARS THE RAP IS TOO FAST. SATELLITE
TIMING TOO INDICATE IT ONLY MOVING WEST AT 5KT AND WOULD MIX OUT
DURING THE DAY AND PERHAPS RETURN WEDNESDAY NIGHT.
THE FCST FOLLOWS NAM WITH INCREASING CLOUDS AFTER MIDNIGHT AND
PATCHY FOG FORMING EAST OF HIGHWAY 61. NO DISCERNIBLE CHANGES IN
THE REST OF THE SHORT TERM FORECAST EXCEPT THE MODELS ARE SHOWING
HIGHER DEW PTS OVERNIGHT WHICH APPEARS TO BE VERIFYING.
UPDATE ISSUED AT 701 PM CST TUE MAR 5 2013
A NEW FORECAST IS OUT. RAISED OVERNIGHT LOW TEMPS A BIT IN THE
WEST WHERE A LOW LEVEL JET SHOULD KICK UP IN A FEW HOURS. LOWS
AROUND 10 TO SINGLE DIGITS EAST OF HIGHWAY 83 WHERE WINDS WILL
REMAIN CALM MOST OF THE NIGHT.
SOUTH WINDS INCREASE TO 20 TO 30 MPH WEDNESDAY AND A BLEND OF THE
NAM...GEM AND ECM INDICATED HIGHS IN THE 30S AND 40S...NO REAL
CHANGE FROM THE PREVIOUS FCST. THE NAM AND GFS SUGGEST SOME
CLOUDINESS MAY DEVELOP EAST OF HIGHWAY 83 IN THE AFTN AS RETURN
MOISTURE DEVELOPS.
EITHER FOG OR LOW CLOUDINESS DEVELOPS WEDNESDAY NIGHT WITH LOWS
IN THE 20S. SOUTH WINDS CONTINUE TO RETURN MOISTURE.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 320 PM CST TUE MAR 5 2013
TEMPERATURES THIS EVENING WILL DROP QUICKLY AS A SFC HIGH PRESSURE
MOVES ACROSS THE NORTHERN PLAINS. LIGHT WINDS...CLEAR SKIES...AND A
RELATIVELY DRY AIRMASS WILL PROVIDE FOR EFFICIENT RADIATIVE COOLING
AND LOWS IN THE LOW TO MID TEENS FOR MOST OF THE CWA. HOWEVER...AS
THE SFC HIGH SLIDES EAST OF THE AREA WINDS WILL INCREASE OUT OF THE
SOUTH FROM WEST TO EAST ACROSS THE CWA. THIS MAY ALLOW FOR WEAK
MIXING TO OCCUR LATE IN THE OVERNIGHT TOWARD EARLY TOMORROW MORNING
AND LIMIT THE PERIOD OF DIURNAL COOLING. EXPECTING OVERNIGHT LOWS TO
OCCUR EARLY BEFORE HOLDING STEADY OR EVEN WARMING A FEW DEGREES BY
DAY BREAK WEDNESDAY.
WINDS WILL CONTINUE TO INCREASE OUT OF THE SOUTH SOUTHEAST DURING
THE DAY WEDNESDAY...WITH 15 TO 25 MPH WINDS LIKELY DURING THE
AFTERNOON. CLEAR SKIES WILL CONTINUE WITH DRY AIRMASS STILL IN
PLACE. HIGH TEMPERATURES WILL BE LIMITED FOR THE EASTERN TWO-THIRDS
OF THE CWA AS 850MB TEMPS STRUGGLE TO RECOVER. EXPECTING HIGHS ONLY
IN THE 40S FOR MOST OF THE AREA...WITH 50S POSSIBLE IN THE EAST
PANHANDLE AND FAR SOUTHWEST NEBRASKA.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 320 PM CST TUE MAR 5 2013
WEDNESDAY NIGHT THROUGH FRIDAY...MAIN FORECASTING
CHALLENGE FOR THE LATTER HALF OF THE WORK WEEK DEALS WITH
TEMPERATURES...MAINLY HIGHS ON THURSDAY AND FRIDAY AS A DEEP TROUGH
OF LOW PRESSURE ALOFT DEEPENS ACROSS THE SWRN CONUS. ON THURSDAY
WARMER AIR WILL PUSH INTO THE PANHANDLE AND WESTERN AREAS WITH SRLY
WINDS DEVELOPING IN THE AFTERNOON HOURS. FURTHER EAST
HOWEVER...LIGHT SERLY AND VARIABLE WINDS IN THE CENTRAL AND EASTERN
CWA WILL LIMIT THE WARMUP TO THE UPPER 40S/LWR 50S VS. THE UPPER 50S
TO NEAR 60 OUT WEST. ON THURSDAY NIGHT...A WEAK COOL FRONT WILL PUSH
ACROSS WESTERN AND NORTH CENTRAL NEBRASKA...STALLING ACROSS NRN KS
AND SERN NEBRASKA. SURFACE LOW PRESSURE WILL DEEPEN FRIDAY ACROSS
EASTERN COLORADO...LIFTING THE FRONT NORTH INTO SOUTH CENTRAL AND
EASTERN NEBRASKA. HOWEVER...THE FRONT IS EXPECTED TO STAY OFF TO THE
SOUTH OF THE FORECAST AREA FRIDAY...LEADING TO EASTERLY UPSLOPE
WINDS AND HIGHS IN THE 40S. EVEN HIGHS IN THE 40S...MAY BE OVERLY
OPTIMISTIC.
FRIDAY NIGHT THROUGH TUESDAY...MAIN FORECASTING CHALLENGE
CONTINUES TO BE PRECIPITATION AND PRECIPITATION TYPE IN
ASSOCIATION WITH A DEEP TROUGH OF LOW PRESSURE...WHICH TRACKS
ACROSS THE CENTRAL CONUS THIS WEEKEND. THE LATEST 12Z GFS THIS
MORNING AND THE 00Z ECMWF FROM LAST NIGHT HAVE DECENT AGREEMENT
WITH THE H5 LOW POSN SATURDAY AT 12Z. AFTER THIS
POINT...DIFFERENCES WITH THE MODEL SOLUTIONS EMERGE...IN
PARTICULAR...WHETHER THE LOW PHASES WITH THE NRN STREAM OR NOT. BY
12Z SUNDAY...THE 12Z GFS FROM THIS MORNING...PHASES THE LOW WITH
THE NRN STREAM...BECOMES POSITIVELY TILTED...AND MOVES THE SYSTEM
INTO THE MID MISSISSIPPI VALLEY BY MONDAY MORNING. THE ECMWF FROM
LAST NIGHT...IS DISCONNECTED FROM THE NRN STREAM...NEUTRAL TILTED
AND REMAINS JUST OFF TO THE SOUTH OF THE CWA THROUGH 12Z MONDAY.
THE DIFFERENCES ARE HUGE IN THE AMOUNT OF QPF GENERATED BY EACH
SOLUTION THROUGH TUESDAY. FOR EXAMPLE...FOR NORTH PLATTE ACCUM QPF
RANGES ANYWHERE FROM 0.30 WITH THE 12Z GFS SOLN...TO 2.30 INCHES
WITH THE 00Z ECMWF. THE CURRENT INHERITED FORECAST...HAS THE BEST
PRECIPITATION CHANCES FROM LATE FRIDAY NIGHT THROUGH SUNDAY
MORNING AND WILL LEAVE THIS AS IS FOR NOW GIVEN THE TIMING
UNCERTAINTIES IN THE MODELS. AS FOR PRECIPITATION TYPES...MEX AND
ECE TEMPERATURES ACROSS THE SRN AND EASTERN CWA...FAVOR ALL RAIN
AT THIS JUNCTURE...WITH A MIX AND ALL SNOW IN THE WESTERN PORTION
OF THE CWA. IF THE MORE PROGRESSIVE GFS SOLUTION VERIFIES...SNOW
AMOUNTS WILL BE MUCH LIGHTER COMPARED TO THE SLOWER 00Z EC
SOLUTION. WILL TAKE A CLOSE LOOK AT THE 12Z EC SOLUTION...AND IF
IT IS PROGRESSIVE LIKE THE 12Z GFS...SOME ELIMINATION OF POPS ON
MONDAY AND TUESDAY MAY BE IN ORDER. IN ADDITION TO ELIMINATING
POPS MONDAY AND TUESDAY...IF THE MODEL COMES IN FASTER WITH THE
SYSTEM...THE THREAT FOR LARGE ACCUMULATING SNOWS AND LONG DURATION
PRECIPITATION WILL BE MINIMIZED.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 524 PM CST TUE MAR 5 2013
VFR IS EXPECTED ALL AREAS TONIGHT THROUGH 21Z WEDNESDAY.
THEREAFTER...THERE ARE INDICATIONS IN THE MODELS THAT THE CLOUD
DECK ACROSS THE MISSOURI BASIN WILL GET SWEPT WESTWARD AFFECTING
AREAS EAST OF HIGHWAY 83. FLIGHT CONDITIONS COULD STILL REMAIN VFR
AS CIGS WOULD OPERATE AT BKN035 BUT LOWER CIGS MIGHT DEVELOP.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...CDC
SYNOPSIS...CLB
SHORT TERM...MARTIN
LONG TERM...CLB
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS BUFFALO NY
355 AM EST WED MAR 6 2013
.SYNOPSIS...
A SNOWSTORM WILL SLIDE SOUTHEAST ACROSS THE VIRGINIAS TODAY...WHILE
JUST BRINGING SOME CLOUDS TO OUR AREA. AN UPPER LEVEL DISTURBANCE
WILL THEN BRING A CHANCE FOR SOME LIGHT RAIN AND SNOW SHOWERS
THURSDAY...WITH SOME STEADIER SNOW THEN EXPECTED FOR AREAS ALONG AND
EAST OF THE GENESEE VALLEY THURSDAY NIGHT INTO EARLY FRIDAY. AFTER
THAT...A RETURN TO DRY WEATHER AND INCREASING WARMTH WILL FOLLOW FOR
THE WEEKEND WITH TEMPERATURES RISING ABOVE NORMAL.
&&
.NEAR TERM /THROUGH TONIGHT/...
IN THIS PERIOD...A COMPLEX WINTER STORM DRAPED FROM SOUTHERN OHIO TO
NORTH CAROLINA WILL CONSOLIDATE INTO A SINGLE LOW ALONG THE VIRGINIA
COASTLINE TODAY...BEFORE SLOWLY DRIFTING OFFSHORE TONIGHT IN
RESPONSE TO A STRONG SHORTWAVE TROUGH DROPPING SOUTHEAST INTO THE
GREAT LAKES. ON SUCH A TRACK...THIS SYSTEM/S SHIELD OF STEADY
PRECIPITATION WILL REMAIN TO OUR SOUTH...WHILE OUR AREA REMAINS
MAINLY DRY WITH JUST A GENERAL INCREASE IN CLOUD COVER EXPECTED
OVER TIME. THE BEST CHANCES FOR ANY PRECIP MAY ACTUALLY COME LATER
TONIGHT AS THE AFOREMENTIONED SHORTWAVE TROUGH APPROACHES FROM THE
NORTHWEST...HOWEVER THE MOISTURE AND LIFT ASSOCIATED WITH THIS LOOKS
WEAK ENOUGH TO KEEP POPS CONFINED TO THE SLIGHT CHANCE RANGE AND
BELOW.
WITH REGARD TO TEMPS...925 MB TEMPS SHOULD RECOVER BACK INTO THE -1C
TO -3C RANGE TODAY AS WARMER AIR GETS DRAWN WESTWARD AROUND THE
NORTH SIDE OF STORM SYSTEM. EVEN WITH AN INCREASE IN CLOUD COVER
EXPECTED AND WINDS TURNING MORE NORTHEASTERLY OVER TIME...THIS
SHOULD STILL BE ENOUGH FOR HIGHS TO REACH INTO THE MID TO UPPER 30S
TODAY...WITH SOME SPOTS IN THE FINGER LAKES LIKELY REACHING 40
DEGREES. UNDER INCREASED AMOUNTS OF CLOUD COVER...LOWS TONIGHT WILL
THEN RANGE FROM THE LOWER 20S ACROSS INTERIOR PORTIONS OF THE
SOUTHERN TIER AND NORTH COUNTRY...TO THE UPPER 20S ACROSS THE LAKE
PLAINS SOUTH OF LAKE ONTARIO.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
UNSETTLED WEATHER WILL RETURN TO WESTERN AND NORTH CENTRAL NEW YORK
ON THURSDAY AS AN UPPER LEVEL LOW WILL DIVE SOUTHEAST ACROSS THE
AREA FROM THE UPPER GREAT LAKES. LOOK FOR SCATTERED RAIN AND SNOW
SHOWERS TO DEVELOP DURING THE DAY ON THURSDAY AND CHANGE OVER TO
MAINLY SNOW SHOWERS DURING THE AFTERNOON AND EVENING AS THE COLD
CORE OF THE LOW MOVES OVERHEAD. ACTIVITY ACROSS WESTERN NEW YORK
SHOULD BE SCATTERED ENOUGH GIVEN THE POSITION DIRECTLY UNDERNEATH
THE PASSING LOW AND TEMPERATURES SHOULD BE WARM ENOUGH THAT ANY SNOW
ACCUMULATIONS SHOULD BE NEGLIGIBLE...ON THE ORDER OF A TENTH OR TWO
ACROSS HIGHER ELEVATIONS OF THE SOUTHERN TIER WITH LITTLE IF ANY
ACCUMULATIONS ELSEWHERE.
EAST OF THE GENESEE VALLEY AND ACROSS THE NORTH COUNTRY THERE IS A
POTENTIAL FOR MORE SIGNIFICANT SNOW ACCUMULATIONS. AS THE SHORTWAVE
DIVES ACROSS WESTERN NEW YORK...THERE IS A POSSIBILITY THAT IT MAY
INTERACT WITH AN INVERTED SURFACE TROUGH PROGGED TO EXTEND ACROSS
THE HUDSON VALLEY AND UPSTATE NEW YORK FROM THE STORM SYSTEM
CURRENTLY IMPACTING THE MID-ATLANTIC STATES TO PRODUCE SIGNIFICANT
ACCUMULATIONS OF SNOW ACROSS PORTIONS OF UPSTATE NEW YORK INCLUDING
THE COUNTIES EAST AND SOUTHEAST OF LAKE ONTARIO. HOWEVER AT THIS
POINT THERE IS STILL A FAIR AMOUNT OF UNCERTAINTY AS TO HOW FAR
NORTH/WEST THIS POTENTIAL BAND OF SNOW WILL DEVELOP AS THIS
DEVELOPMENT WILL HINGE ON THE SPEED OF THE UPPER LEVEL TROUGH AND
EXACTLY HOW FAR INLAND THE DEEPEST MOISTURE AND WARM ADVECTION WILL
PENETRATE...WHICH IS ITSELF A FUNCTION OF THE EXACT TRACK OF THE
DEVELOPING STORM SYSTEM AS IT DEPARTS THE EAST COAST. GIVEN ALL OF
THE COMPLEX ISSUES...WILL HOLD OFF ON ANY WATCHES AT THIS POINT AND
LOOK FOR GREATER CLARITY IN FUTURE MODEL RUNS.
A ROBUST RIDGE OF HIGH PRESSURE WILL BUILD ACROSS THE LOWER GREAT
LAKES ON FRIDAY IN THE WAKE OF THE DEPARTING LOW BRINGING A RETURN
TO DRY WEATHER. NORTHERLY FLOW AHEAD OF THE HIGH WILL LIKELY KEEP A
DECENT AMOUNT OF CLOUD COVER IN PLACE ACROSS THE AREA FOR MUCH OF
THE DAY AND THIS MAY HOLD TEMPERATURES IN THE MID TO UPPER 30S...HOWEVER
CLOUDS SHOULD GRADUALLY THIN OUT AS DRIER AIR WORKS ITS WAY ACROSS
THE REGION LATER FRIDAY AFTERNOON AND EVENING. THE CLEARING SKIES
AND DIMINISHING WINDS AS THE SURFACE HIGH MOVES OVERHEAD FRIDAY
NIGHT WILL ALLOW TEMPERATURES TO DROP INTO THE 20S EVEN AS
TEMPERATURES ALOFT RISE ABOVE NORMAL.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
THE RIDGE WILL SLIDE OFF TO THE EAST EARLY IN THE PERIOD AS BOTH
THE GFS AND ECMWF SHOW A WEAK FRONTAL BOUNDARY CROSSING THE LOWER
LAKES LATE IN THE WEEKEND. TIMING OF THE FRONTAL BOUNDARY IS
HANDLED DIFFERENT BY THE TWO MODELS...AS THE MODELS HAVING
DIFFICULTY HANDLING THE SHORT WAVE ENERGY COMING OUT OF THE PLAINS
AND DAMPENING THE UPPER RIDGE. IT DOES APPEAR THAT MOISTURE WILL
BE LIMITED ENOUGH TO KEEP PRECIPITATION IN THE BROADBRUSH LOW
CHANCE CATEGORY...BUT THAT IS AS MUCH DETAIL AS CAN BE AFFORDED AT
THIS POINT. USED A CONSENSUS OF GUIDANCE FOR THIS PERIOD GIVEN THE
LIMITED CONFIDENCE IN ANY ONE MODEL.
EVEN MORE UNCERTAINTY AND LOWER CONFIDENCE DEVELOPS EARLY NEXT WEEK
AS MODELS STRUGGLE TO CONSISTENTLY HANDLE THE PHASING OF THE
NORTHERN AND SOUTHERN STREAMS OVER THE CONUS. CONTINUED TO USE A
CONSENSUS OF GUIDANCE...BUT OVERALL CONFIDENCE IN THIS PORTION OF
THE FORECAST IS BELOW AVERAGE.
THE OVERALL TEMPERATURE PATTERN SHOULD FEATURE A GENERAL WARMER THAN
NORMAL REGIME.
&&
.AVIATION /09Z WEDNESDAY THROUGH SUNDAY/...
AS OF 08Z...SKIES REMAIN MAINLY CLEAR NORTH OF THE SOUTHERN
TIER...WHILE SOME THICKER CIRRUS AND PATCHY STRATUS PERSIST FROM
KJHW OVER TO KELZ. THROUGH SUNRISE...EXPECT A SUBSIDENCE INVERSION
TO CONTINUE TO LOWER AND SHARPEN AND LIKELY LEAD TO SOME EXPANSION
OF THE LOWER CLOUDS...HOWEVER THESE WILL REMAIN PATCHY IN COVERAGE
AND MVFR IN NATURE GIVEN ONLY MARGINAL MOISTURE...WITH CONFIDENCE IN
TIMING/LOCATION REMAINING LOW. BASED ON THE LATEST RAP AND THE 18Z
NAM...WILL CARRY A PERIOD OF LLWS AT JHW.
THROUGH THE REMAINDER OF TODAY AND TONIGHT...LOW PRESSURE WILL
REMAIN WELL SOUTH AND EAST OF THE AREA. OVER TIME...INITIAL VFR/
PATCHY MVFR CONDITIONS THIS MORNING WILL GRADUALLY LOWER TO MVFR AS
MOISTURE INCREASES IN THE LOWER LEVELS OF THE ATMOSPHERE...WITH SOME
IFR CIGS BECOMING POSSIBLE ACROSS THE SOUTHERN TIER TONIGHT.
OUTLOOK...
THURSDAY...MVFR WITH A CHANCE OF RAIN AND SNOW SHOWERS.
THURSDAY NIGHT...MVFR/IFR WITH LIGHT SNOW LIKELY FROM THE GENESEE
VALLEY EASTWARD...OTHERWISE MVFR WITH A CHANCE OF SNOW SHOWERS
FURTHER WEST.
FRIDAY...MVFR WITH A CHANCE OF SNOW SHOWERS IN THE MORNING...THEN
BECOMING MAINLY VFR.
SATURDAY AND SUNDAY...VFR.
&&
.MARINE...
COMPLEX LOW PRESSURE DRAPED FROM SOUTHERN OHIO TO NORTH CAROLINA
WILL CONSOLIDATE INTO A SINGLE LOW ALONG THE VIRGINIA COASTLINE
TODAY...BEFORE SLOWLY DRIFTING OUT TO SEA TONIGHT AND THURSDAY. AS
THIS SYSTEM PUSHES EASTWARD...THE BRISK EASTERLY FLOW CURRENTLY
FOUND ACROSS THE LOWER LAKES WILL TURN MORE NORTHEASTERLY TODAY...
THEN WILL GRADUALLY WEAKEN TONIGHT AND THURSDAY WHILE ALSO TENDING
MORE NORTHERLY. THIS WILL EVENTUALLY LEAD TO WINDS AND WAVES FALLING
BELOW ADVISORY CRITERIA OVER TIME...HOWEVER UNTIL THIS HAPPENS SMALL
CRAFT ADVISORIES WILL REMAIN IN EFFECT AS OUTLINED BELOW.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 10 AM EST THIS MORNING FOR LEZ040.
SMALL CRAFT ADVISORY UNTIL 10 PM EST THIS EVENING FOR
LOZ043.
SMALL CRAFT ADVISORY FROM 7 AM THIS MORNING TO 10 PM EST
THIS EVENING FOR LOZ044.
SMALL CRAFT ADVISORY UNTIL 10 PM EST THIS EVENING FOR
LOZ042.
&&
$$
SYNOPSIS...JJR
NEAR TERM...JJR
SHORT TERM...WOOD
LONG TERM...TMA
AVIATION...APFFEL/JJR
MARINE...JJR
AREA FORECAST DISCUSSION
NWS RALEIGH NC
250 PM EST WED MAR 6 2013
.SYNOPSIS...
A POWERFUL LOW PRESSURE SYSTEM OVER COASTAL VIRGINIA WILL MOVE
OFFSHORE THROUGH TONIGHT. DRY HIGH PRESSURE WILL BUILD OVER THE
EASTERN SEABOARD THURSDAY THROUGH THE WEEKEND.
&&
.NEAR TERM /THROUGH THURSDAY NIGHT/...
AS OF 235 PM WEDNESDAY...
THROUGH TONIGHT: IMPROVING WEATHER EXPECTED TONIGHT. LATEST SURFACE
MAP SHOWS THE STRONG SURFACE LOW NEAR THE MOUTH OF CHESAPEAKE BAY.
BANDS OF RAIN AND SNOW SHOWERS CONTINUE TO PIVOT AROUND THE LOW INTO
NORTHEAST NC... ALTHOUGH THUS FAR THIS AFTERNOON -- IN CONTRAST TO
THIS MORNING`S HRRR GUIDANCE -- THE SIGNIFICANT REFLECTIVITIES HAVE
HELD LARGELY NORTH AND EAST OF OUR FORECAST AREA. EXTRAPOLATION OF
EXISTING UPSTREAM PRECIP AND LOCAL WRF OUTPUT STILL SUPPORT PRECIP
WORKING ACROSS THE NORTHEAST CWA... ALONG AND NE OF A LINE FROM
OXFORD TO WILSON... FOR THE NEXT FEW HOURS. SURFACE WET BULBS ARE
GENERALLY ABOVE FREEZING IN THIS AREA... SO EXPECT A PTYPE OF MOSTLY
RAIN... ALTHOUGH HEAVIER BANDS MAY STILL MIX WITH A LITTLE
INCONSEQUENTIAL WET SNOW IN THE FAR NORTHEAST. THE LOW SWINGS
FARTHER OUT TO SEA THIS EVENING... LEAVING LITTLE MORE THAN PATCHY
SPRINKLES BEFORE THE PRECIP THREAT ENDS ENTIRELY BY MIDNIGHT.
REGARDING THE WINDS... WE`VE HAD NUMEROUS SITES ATTAIN PEAK GUSTS OF
40-46 MPH SO FAR TODAY WITH NEARLY ALL LOCATIONS SEEING 30 MPH GUSTS
OR GREATER. THE DEPARTURE OF THE COASTAL LOW AND SUBSEQUENT SLOW
SLACKENING OF THE MSLP GRADIENT AND GRADUAL DECREASE IN NEAR-SURFACE
MIXING WILL RESULT IN SLOWLY DECREASING WINDS AS WE GO THROUGH THE
EVENING. WILL LEAVE THE WIND ADVISORY IN PLACE UNTIL MIDNIGHT...
ALTHOUGH IT MAY NEED TO BE CANCELED A FEW HOURS EARLY. EXPECT
GRADUAL CLEARING SKIES FROM SW TO NORTHEAST AS WE DRY OUT IN THE
LOWEST FEW THOUSAND FEET. DESPITE DEW POINTS IN THE 20S THROUGH
TONIGHT... THE AIR SHOULD STAY JUST STIRRED ENOUGH NEAR THE GROUND
TO KEEP LOWS UP A BIT... 29-34.
FOR THURSDAY/THURSDAY NIGHT: WITH THE COLUMN DRYING OUT AND SINKING/
STABILIZING ALOFT... EXPECT QUITE A BIT OF SUNSHINE WITH PERHAPS
SOME FLAT AFTERNOON CUMULUS. SURFACE HIGH PRESSURE CENTERED OVER
ONTARIO AND THE UPPER MIDWEST/UPPER GREAT LAKES WILL EXTEND
SOUTHWARD WITH RIDGING BUILDING SLOWLY INTO NC FROM THE NW. WINDS
FROM THE NNW WILL NOT BE NEARLY AS STRONG AS THEY HAVE BEEN TODAY
BUT THE MSLP GRADIENT REMAINS TIGHT ENOUGH TO TRANSLATE INTO SURFACE
WINDS OF 10-15 KTS AND PERIODIC GUSTS TO 15-20 KTS BASED ON
PROJECTED WINDS IN THE UPPER PORTIONS OF THE MIXED LAYER. LOW LEVEL
THICKNESSES WILL BE AROUND 20-25 METERS BELOW NORMAL... SUGGESTING
HIGHS OF 51-58... OR ROUGHLY TWO CATEGORIES BELOW NORMAL. THE MID
LEVEL LOW NEAR LAKE SUPERIOR THIS MORNING WILL DROP TOWARD THE
SOUTHEAST OVER PA/DEL LATE THURSDAY NIGHT... HOWEVER THE LACK OF
MOISTURE AT ANY LEVEL AND NO OPPORTUNITY FOR AN MOISTURE TRANSPORT
INTO NC WITH LOW LEVEL FLOW FROM THE NNW WILL ALLOW SKIES TO STAY
GENERALLY CLEAR. LOWS 28-33 WITH 4-8 KTS OF WIND FROM THE NORTH.
-GIH
&&
.SHORT TERM /FRIDAY AND SUNDAY NIGHT/...
AS OF 250 PM WEDNESDAY...
AN OMEGA BLOCK WILL DEVELOP BY FRIDAY AS THE UPPER LOW OFF THE MID
ATLANTIC COAST CONTINUES TO WOBBLE SLOWLY TOWARD THE NORTH
ATLANTIC AND A CUTOFF LOW DEVELOPS OVER THE SOUTHWESTERN US.
MEANWHILE...A DISTURBANCE CURRENTLY MOVING INTO THE UPPER GREAT
LAKES AREA WILL BE DRAWN SOUTH ACROSS THE MID-ATLANTIC STATES AND
CLIP NORTHEASTERN NC EARLY FRIDAY. DEEP MOISTURE IS FORECAST TO BE
RATHER LIMITED...BUT ENHANCE CLOUD COVER OVER AT LEAST THE NORTHERN
COASTAL PLAIN SEEMS FAIRLY LIKELY WITH THE GLANCING BLOW OF THE VORT
MAX. FORECAST SOUNDINGS ALSO SHOW PERSISTENT BACKING OF THE LOW
LEVEL FLOW...WITH 10-15KT SURFACE WIND...SUGGESTING ANOTHER SURGE OF
COLD ADVECTION BEFORE HIGH PRESSURE BUILDS IN FROM THE GREAT LAKES
FRIDAY NIGHT. THUS...WILL KEEP HIGHS A GOOD 4-6 DEGREES BELOW MOST
GUIDANCE ON FRIDAY...49-55 NORTHEAST TO SOUTHWEST. LOWS FRIDAY
NIGHT IN THE UPPER 20S TO LOWER 30S.
RIDGING ALOFT WILL BUILD OVER HEAD SATURDAY THROUGH SUNDAY...WHILE
SURFACE HIGH PRESSURE SETTLES ALONG THE EAST COAST. THIS WILL LEAD
TO A MODERATING TREND IN TEMPS AS 850MB TEMPS APPROACH 10C AND LOW
LEVEL THICKNESSES RISE ABOVE 1350M BY SUNDAY.
HOWEVER...NORTHEASTERLY LOW LEVEL FLOW IS FORECAST
TO CONTINUE SATURDAY...SO THE WARMING ALOFT MAY NOT BE COMPLETELY
REALIZED FOR YET ANOTHER DAY. THE MORE NOTICEABLE WARMUP WILL BE
FELT IN THE NORTHEAST CWA ON SATURDAY...WITH HIGHS RANGING FROM THE
MID 50S NORTHEAST TO AROUND 60 SOUTHWEST. THE SURFACE HIGH IS
FORECAST TO SHIFT OFFSHORE BY SUNDAY...AND IF THIS OCCURS...THEN
WEAK RETURN FLOW WOULD DEVELOP AND HELP PUSH HIGHS INTO THE MID
60S. DRY CONDITIONS WILL PERSIST BENEATH THE RIDGE.
&&
.LONG TERM /MONDAY THROUGH WEDNESDAY/...
AS OF 250 PM WEDNESDAY...
THE OMEGA BLOCK OVER THE CONUS IS FORECAST TO WEAKEN BY
MONDAY..ALLOWING AN UPPER LOW OVER THE SOUTHWESTERN US TO EJECT
EASTWARD ACROSS THE SOUTHERN PLAINS AND DEAMPLIFY AS IT LIFTS TOWARD
THE MIDWEST STATES . SOUTHERLY RETURN FLOW AHEAD OF THE SYSTEM
SHOULD PUSH TEMPS WELL ABOVE NORMAL MONDAY WITH LOW LEVEL THICKNESSES
PROGGED TO APPROACH 1360M. BASED ON THIS...UPPER 60S SEEM LIKELY
AND LOWER 70S POSSIBLE UNLESS CLOUD COVER IS MORE ROBUST THAN
FORECAST. AS THE UPPER TROUGH AND PRIMARY SURFACE LOW LIFT ACROSS
THE MIDWEST AND OH VALLEY...THE ATTENDANT COLD FRONT IS EXPECTED TO
MOVE CROSS THE MOUNTAINS MONDAY NIGHT/TUESDAY. THE GFS AND ECMWF
HAVE WAVERED BACK AND FORTH A BIT REGARDING THE EXACT TIMING OF THE
FRONTAL PASSAGE AND SENSIBLE WEATHER...BUT THEIR SOLUTIONS ARE
GENERALLY WITHIN 12 HOURS OF EACH OTHER. HOWEVER...THERE ARE STILL
ENOUGH DIFFERENCES IN THE MASS FIELDS TO KEEP POPS BELOW 50 PERCENT
AT THIS TIME. SHOULD ALSO NOTE THAT AS WE MOVE FURTHER INTO
MARCH...THIS TYPE OF PATTERN WILL BRING A BETTER CHANCE OF
THUNDERSTORMS ACCOMPANYING THE COLD FRONT...BUT WE WILL HOLD OFF ON
INCLUDING THUNDER IN THE FORECAST UNTIL TIMING OF THE SYSTEM AND
MOISTURE RETURN ARE MORE CERTAIN.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 1230 PM WEDNESDAY...
VFR CONDITIONS ARE EXPECTED TO PERSIST AT INT/GSO/FAY WELL INTO
WEDNESDAY. RDU/RWI WILL REMAIN CLOSER TO THE LOW CLOUD SHIELD (MVFR
TO HIGH-END IFR CIGS) ASSOCIATED WITH THE STRONG STORM CENTERED OVER
THE SE COAST OF VA... SO A PERIOD OF MVFR CIGS AND BRIEF MVFR VSBYS
WITHIN LIGHT RAIN SHOWERS (POSSIBLY MIXED WITH WET SNOW) ARE
POSSIBLE THIS AFTERNOON UNTIL 23Z-01Z. AS THIS STORM SYSTEM HEADS
OFF THE COAST THIS EVENING... SKIES WILL CLEAR OUT SW TO NE. STRONG
WINDS COMING FROM THE WEST AND NW WILL REMAIN AN AVIATION HAZARD
THROUGH EARLY TO MID EVENING... PRESENTING A SIGNIFICANT CROSSWIND
PRIMARILY AT GSO/RDU/RWI/FAY. SUSTAINED WINDS OF 15-25 KTS AND GUSTS
TO 30-38 KTS ARE EXPECTED THROUGH 22Z... THEN NW WINDS WILL BE
DIMINISHING THROUGH THE EVENING AS THEY BECOME NORTHERLY. UNLIMITED
SKIES AND NORTH WINDS 7-12 KTS ARE EXPECTED AFTER SUNRISE THURSDAY.
LOOKING BEYOND 18Z THURSDAY... VFR CONDITIONS WILL DOMINATE THROUGH
EARLY FRIDAY. BRIEF MVFR CIGS ARE POSSIBLE FRIDAY AFTERNOON INTO
FRIDAY NIGHT AS LOW PRESSURE MOVES BY TO OUR NORTHEAST. THEN AS A
STORM SYSTEM APPROACHES FROM THE WEST... IFR CIGS ARE POSSIBLE EARLY
MONDAY MORNING... LIFTING TO VFR BY MONDAY AFTERNOON.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR
NCZ007>011-021>028-038>043-073>078-083>086-088-089.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD
SHORT TERM...SMITH
LONG TERM...SMITH
AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
235 PM EST WED MAR 6 2013
.SYNOPSIS...
A POWERFUL LOW PRESSURE SYSTEM OVER COASTAL VIRGINIA WILL MOVE
OFFSHORE THROUGH TONIGHT. DRY HIGH PRESSURE WILL BUILD OVER THE
EASTERN SEABOARD THURSDAY THROUGH THE WEEKEND.
&&
.NEAR TERM /THROUGH THURSDAY NIGHT/...
AS OF 235 PM WEDNESDAY...
THROUGH TONIGHT: IMPROVING WEATHER EXPECTED TONIGHT. LATEST SURFACE
MAP SHOWS THE STRONG SURFACE LOW NEAR THE MOUTH OF CHESAPEAKE BAY.
BANDS OF RAIN AND SNOW SHOWERS CONTINUE TO PIVOT AROUND THE LOW INTO
NORTHEAST NC... ALTHOUGH THUS FAR THIS AFTERNOON -- IN CONTRAST TO
THIS MORNING`S HRRR GUIDANCE -- THE SIGNIFICANT REFLECTIVITIES HAVE
HELD LARGELY NORTH AND EAST OF OUR FORECAST AREA. EXTRAPOLATION OF
EXISTING UPSTREAM PRECIP AND LOCAL WRF OUTPUT STILL SUPPORT PRECIP
WORKING ACROSS THE NORTHEAST CWA... ALONG AND NE OF A LINE FROM
OXFORD TO WILSON... FOR THE NEXT FEW HOURS. SURFACE WET BULBS ARE
GENERALLY ABOVE FREEZING IN THIS AREA... SO EXPECT A PTYPE OF MOSTLY
RAIN... ALTHOUGH HEAVIER BANDS MAY STILL MIX WITH A LITTLE
INCONSEQUENTIAL WET SNOW IN THE FAR NORTHEAST. THE LOW SWINGS
FARTHER OUT TO SEA THIS EVENING... LEAVING LITTLE MORE THAN PATCHY
SPRINKLES BEFORE THE PRECIP THREAT ENDS ENTIRELY BY MIDNIGHT.
REGARDING THE WINDS... WE`VE HAD NUMEROUS SITES ATTAIN PEAK GUSTS OF
40-46 MPH SO FAR TODAY WITH NEARLY ALL LOCATIONS SEEING 30 MPH GUSTS
OR GREATER. THE DEPARTURE OF THE COASTAL LOW AND SUBSEQUENT SLOW
SLACKENING OF THE MSLP GRADIENT AND GRADUAL DECREASE IN NEAR-SURFACE
MIXING WILL RESULT IN SLOWLY DECREASING WINDS AS WE GO THROUGH THE
EVENING. WILL LEAVE THE WIND ADVISORY IN PLACE UNTIL MIDNIGHT...
ALTHOUGH IT MAY NEED TO BE CANCELED A FEW HOURS EARLY. EXPECT
GRADUAL CLEARING SKIES FROM SW TO NORTHEAST AS WE DRY OUT IN THE
LOWEST FEW THOUSAND FEET. DESPITE DEW POINTS IN THE 20S THROUGH
TONIGHT... THE AIR SHOULD STAY JUST STIRRED ENOUGH NEAR THE GROUND
TO KEEP LOWS UP A BIT... 29-34.
FOR THURSDAY/THURSDAY NIGHT: WITH THE COLUMN DRYING OUT AND SINKING/
STABILIZING ALOFT... EXPECT QUITE A BIT OF SUNSHINE WITH PERHAPS
SOME FLAT AFTERNOON CUMULUS. SURFACE HIGH PRESSURE CENTERED OVER
ONTARIO AND THE UPPER MIDWEST/UPPER GREAT LAKES WILL EXTEND
SOUTHWARD WITH RIDGING BUILDING SLOWLY INTO NC FROM THE NW. WINDS
FROM THE NNW WILL NOT BE NEARLY AS STRONG AS THEY HAVE BEEN TODAY
BUT THE MSLP GRADIENT REMAINS TIGHT ENOUGH TO TRANSLATE INTO SURFACE
WINDS OF 10-15 KTS AND PERIODIC GUSTS TO 15-20 KTS BASED ON
PROJECTED WINDS IN THE UPPER PORTIONS OF THE MIXED LAYER. LOW LEVEL
THICKNESSES WILL BE AROUND 20-25 METERS BELOW NORMAL... SUGGESTING
HIGHS OF 51-58... OR ROUGHLY TWO CATEGORIES BELOW NORMAL. THE MID
LEVEL LOW NEAR LAKE SUPERIOR THIS MORNING WILL DROP TOWARD THE
SOUTHEAST OVER PA/DEL LATE THURSDAY NIGHT... HOWEVER THE LACK OF
MOISTURE AT ANY LEVEL AND NO OPPORTUNITY FOR AN MOISTURE TRANSPORT
INTO NC WITH LOW LEVEL FLOW FROM THE NNW WILL ALLOW SKIES TO STAY
GENERALLY CLEAR. LOWS 28-33 WITH 4-8 KTS OF WIND FROM THE NORTH.
-GIH
&&
.SHORT TERM /FRIDAY AND FRIDAY NIGHT/...
AS OF 230 AM WEDNESDAY...
FRIDAY AND FRIDAY NIGHT:
VERTICALLY STACKED LOW PRESSURE SYSTEM IS EXPECTED TO CONTINUE TO
HANG AROUND SEVERAL HUNDRED MILES OFF THE MID ATLANTIC COAST ON
FRIDAY... BEFORE PICKING UP SOME EAST/EAST-SOUTHEASTWARD MOMENTUM ON
FRIDAY NIGHT AS ADDITIONAL S/W ENERGY IN THE FORM OF A BIT WEAKER
CLOSED LOW DIVES SOUTHEASTWARD FROM THE GREAT LAKES REGION THURSDAY
NIGHT INTO FRIDAY (BEFORE BEING ABSORBED BY THE DEEP CYCLONIC VORTEX
OFF THE MID ATLANTIC COAST LATE FRIDAY INTO FRIDAY NIGHT). THIS
ADDITIONAL ENERGY HAS TRENDED A BIT FURTHER WESTWARD WITH ITS
TRACK... YET STILL EXPECTED TO ONLY SIDE SWIPE OUR COASTAL PLAIN AND
NORTHEASTERN PIEDMONT COUNTIES FRIDAY INTO FRIDAY EVENING. GIVEN THE
OVERALL LACK OF MOISTURE EXPECTED ACROSS OUR AREA AND THE CURRENT
TRACK OF THE DISTURBANCE EXPECT WE SHOULD REMAIN DRY... WITH ONLY A
POSSIBLE INCREASE IN SOME CLOUD COVER ON FRIDAY AFTERNOON INTO THE
EVENING ACROSS EASTERN PORTIONS OF CENTRAL NC. HOWEVER... THE CLOUD
COVER COULD HAVE AN IMPACT ON HIGH TEMPERATURES FOR FRIDAY ACROSS
EASTERN/NORTHEASTERN PORTIONS OF THE RAH CWA. PLAN TO GO ON THE
COOLER SIDE OF GUIDANCE FOR MOST OF THE AREA AGAIN GIVEN THIS ALONG
WITH AFTERNOON LOW LEVEL THICKNESS VALUES EXPECTED TO RUN SOME 20 TO
30 METERS BELOW NORMAL FOR THIS TIME OF YEAR... PLUS A POSSIBLE SNOW
PACK TO THE NORTH OF THE CWA WITH CONTINUED NORTH-NORTHWESTERLY LOW
LEVEL FLOW. THIS YIELDS HIGH TEMPS FROM AROUND 50 NE TO THE UPPER
50S SW. IN ADDITION TO THE CHILLY TEMPS... EXPECT WE SHOULD CONTINUE
TO HAVE WINDS IN THE 10 TO 15 MPH RANGE... WITH GUSTS AS HIGH AS 25
MPH.
ANY CLOUD COVER ASSOCIATED WITH THE AFOREMENTIONED DISTURBANCE
SHOULD BEGIN TO SHIFT TO THE EAST OF THE AREA... WITH SUBSIDENCE IN
THE WAKE OF THE DISTURBANCE (NAM WOULD SUGGEST A BIT SLOWER TIMING
BUT APPEARS TO BE A SLOW OUTLIER WRT THE TIMING OF THE DISTURBANCE).
WITH SURFACE HIGH PRESSURE BUILDING INTO THE AREA AND CLEARING SKIES
EXPECT WE WILL SEE TEMPS FALL INTO THE UPPER 20S TO LOWER 30S FOR
LOWS SATURDAY MORNING... WITH A LIGHT NORTH-NORTHWESTERLY BREEZE
OVERNIGHT.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 3 AM WEDNESDAY...
S/W RIDGING IS EXPECTED TO BUILD ACROSS THE REGION FOR THE
WEEKEND... WHILE SURFACE HIGH PRESSURE MOVES ACROSS THE AREA AND
OFFSHORE. THIS WILL RESULT IN QUITE WEATHER ACROSS CENTRAL NC THIS
WEEKEND... WITH A WARMING TREND. EXPECT HIGH TEMPS ON SATURDAY WILL
BE IN THE MID TO UPPER 50S... WITH MAYBE A FEW LOCATIONS TOUCHING 60
ACROSS THE FAR SOUTH OR SOUTHWEST WITH MOSTLY SUNNY SKIES. HIGH
SUNDAY ARE EXPECTED TO BE EVEN WARMER... AS AFTERNOON LOW LEVEL
THICKNESS VALUES ARE EXPECTED TO FINALLY BE SLIGHTLY ABOVE NORMAL.
THUS... EXPECT HIGH TEMPS WILL WARM INTO THE LOWER TO MID 60S BY
SUNDAY AFTERNOON WITH INCREASING HIGH LEVEL CLOUD COVER. LOWS SUNDAY
MORNING ARE EXPECTED TO BE IN THE LOWER TO MID 30S... WITH EXCELLENT
RADIATIONAL COOLING CONDITIONS WITH MOSTLY CLEAR SKIES AND LIGHT AND
VARIABLE TO CALM WINDS AS HIGH PRESSURE ALOFT AND THE SURFACE WILL
SETTLE OVER THE AREA.
THE NEXT SYSTEM IS EXPECTED TO MOVE INTO THE AREA EARLY NEXT WEEK AS
A DEEP TROUGH AND ASSOCIATED COLD FRONT SHIFT EASTWARD AND
EVENTUALLY ACROSS THE REGION. THE OPERATIONAL GFS AND ECMWF HAVE
COME INTO MUCH BETTER AGREEMENT ON THE TIMING OF THE SYSTEM... AND
NOW BOTH SHOW AT LEAST SOME PHASING/INTERACTION OF THIS SYSTEM
(WHICH ORIGINATES FROM A CLOSED LOW IN THE SOUTHWESTERN U.S. LATE
THIS WEEK) WITH A NORTHERN STREAM TROUGH. BOTH THE 00Z ECMWF AND 00Z
GFS SHOW AN AREA OF SHOWERS AND POSSIBLY SOME THUNDERSTORMS MOVING
ACROSS THE AREA LATE MONDAY AFTERNOON INTO TUESDAY MORNING... ALONG
WITH THE PASSAGE OF A STRONG COLD FRONT BY TUESDAY MORNING. WPC
(FORMERLY KNOW AS HPC... NOW THE WEATHER PREDICTION CENTER) PREFERS
A BIT SLOWER TIMING... LAGGING THE TIMING OF THE FRONT AND CONTINUED
CHANCES FOR SHOWERS AND POSSIBLY STORMS INTO THE DAY TUESDAY... AS
THEY PREFER THE EUROPEAN CENTRE ENSEMBLE MEAN AS THEY NOTED IT
OUTSTANDING PERFORMANCE WITH THE SYNOPTIC FLOW OF LATE. THUS... WILL
TREND THE TIMING A BIT SLOWER THAN THE CURRENT OPERATIONAL MODELS
ADVERTISE... WITH A GOOD CHANCE OF RAIN STILL LATE MONDAY INTO
TUESDAY MORNING. EXPECT HIGHS TO BE IN THE 60S TO POSSIBLY 70S EAST
MONDAY... WITH UPPER 50S TO 60S TUESDAY (HIGHLY DEPENDENT ON THE
TIMING OF THE FRONT). LOWS EARLY NEXT WEEK ARE EXPECTED TO BE IN THE
40S TO EVEN AROUND 50 ON TUESDAY MORNING (AGAIN TIED TO THE EVENTUAL
TIMING OF THE FRONT).
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 1230 PM WEDNESDAY...
VFR CONDITIONS ARE EXPECTED TO PERSIST AT INT/GSO/FAY WELL INTO
WEDNESDAY. RDU/RWI WILL REMAIN CLOSER TO THE LOW CLOUD SHIELD (MVFR
TO HIGH-END IFR CIGS) ASSOCIATED WITH THE STRONG STORM CENTERED OVER
THE SE COAST OF VA... SO A PERIOD OF MVFR CIGS AND BRIEF MVFR VSBYS
WITHIN LIGHT RAIN SHOWERS (POSSIBLY MIXED WITH WET SNOW) ARE
POSSIBLE THIS AFTERNOON UNTIL 23Z-01Z. AS THIS STORM SYSTEM HEADS
OFF THE COAST THIS EVENING... SKIES WILL CLEAR OUT SW TO NE. STRONG
WINDS COMING FROM THE WEST AND NW WILL REMAIN AN AVIATION HAZARD
THROUGH EARLY TO MID EVENING... PRESENTING A SIGNIFICANT CROSSWIND
PRIMARILY AT GSO/RDU/RWI/FAY. SUSTAINED WINDS OF 15-25 KTS AND GUSTS
TO 30-38 KTS ARE EXPECTED THROUGH 22Z... THEN NW WINDS WILL BE
DIMINISHING THROUGH THE EVENING AS THEY BECOME NORTHERLY. UNLIMITED
SKIES AND NORTH WINDS 7-12 KTS ARE EXPECTED AFTER SUNRISE THURSDAY.
LOOKING BEYOND 18Z THURSDAY... VFR CONDITIONS WILL DOMINATE THROUGH
EARLY FRIDAY. BRIEF MVFR CIGS ARE POSSIBLE FRIDAY AFTERNOON INTO
FRIDAY NIGHT AS LOW PRESSURE MOVES BY TO OUR NORTHEAST. THEN AS A
STORM SYSTEM APPROACHES FROM THE WEST... IFR CIGS ARE POSSIBLE EARLY
MONDAY MORNING... LIFTING TO VFR BY MONDAY AFTERNOON.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR
NCZ007>011-021>028-038>043-073>078-083>086-088-089.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD
SHORT TERM...BSD
LONG TERM...BSD
AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1230 PM EST WED MAR 6 2013
.SYNOPSIS...
A POWERFUL LOW PRESSURE SYSTEM OVER SOUTHEAST VIRGINIA WILL MOVE
SLOWLY EAST OUT OVER THE ATLANTIC LATER TODAY THROUGH TONIGHT. DRY
HIGH PRESSURE WILL SLOWLY BUILD OVER THE EASTERN SEABOARD THURSDAY
THROUGH THE WEEKEND.
&&
.NEAR TERM /THROUGH THURSDAY NIGHT/...
AS OF 955 AM WEDNESDAY...
REST OF TODAY: STRONG GRADIENT WINDS AND THE CHANCE OF SNOW SHOWERS
OVER NORTH CENTRAL SECTIONS REMAIN SIGNIFICANT FORECAST CONCERNS.
LATEST SURFACE MAP SHOWS THE SURFACE LOW CENTER JUST NORTH OF
WILLIAMSBURG VA. MOSTLY LIGHT SNOW SHOWERS... OCCASIONALLY CHANGING
BACK TO RAIN WHEN RATES DECREASE... CONTINUE TO PIVOT OVER THE FAR
NORTH CENTRAL AND NORTHEAST CWA. WE`VE RECEIVED A FEW REPORTS OF
LIGHT ACCUMULATION ON GRASSY AREAS FROM A FEW SPOTS THIS MORNING...
AND THIS SEEMS TO HAVE BEEN THE CASE BENEATH THE AREAS OF HEAVIER
REFLECTIVITIES... ONE BAND OF WHICH IS PROGRESSING THROUGH FRANKLIN
TOWARD NASH COUNTY. WE ARE STILL CANVASSING THE COUNTIES AND TOWNS
THERE TO DETERMINE THE DEGREE OF IMPACT OF THE SNOW THAT HAS FALLEN
SO FAR... BUT BASED ON THE RADAR TRENDS AND RECENT HRRR RUNS WHICH
SUGGEST THAT SOME OF THE HEAVIER SNOW SHOWERS OVER SOUTH CENTRAL VA
MAY TRACK SOUTH OF THE BORDER... A SHORT-TERM ADVISORY MAY BE NEEDED
HERE. IN ANY CASE... BASED ON THE OBSERVED AND EXPECTED WET BULB
TEMPS THAT SHOULD HOLD VERY CLOSE TO FREEZING OR JUST ABOVE... AND
WITH FAIRLY MILD ROAD TEMPS... ROADS SHOULD BE JUST WET WITH ANY
ACCUMULATION ON THE GRASSY AREAS ONLY. WILL CONTINUE TO MONITOR. THE
WIND ADVISORY WILL REMAIN AS IS. SEVERAL GUSTS OVER 30 KTS HAVE
ALREADY BEEN REPORTED... PRIMARILY IN LOCATIONS THAT HAVE SEEN SOME
SUNSHINE THIS MORNING... IN THE FAR WEST AND ACROSS THE SOUTHERN
CWA. OBSERVED 925 MB TEMPS FROM UPPER AIR SOUNDINGS ARE AROUND 30
KTS... AND AROUND 35-40 KT AT 850 MB... SO WITH GOOD MIXING EXPECT
FREQUENT GUSTS TO AROUND 35-45 MPH. HIGHS FROM 36-40 NORTH TO AROUND
50 IN THE SOUTH. -GIH
TONIGHT...SHOULD SEE PRECIP CHANCES END EARLY IN THE FAR NE AS THE
LOW PRESSURE SYSTEM PULLS FARTHER AWAY. CLEARING SKIES WILL TREND
EWD DURING THE NIGHT. DUE TOT HE LARGE WIND FIELD ASSOCIATED WITH
THE SYSTEM...EXPECT WINDY/BREEZY CONDITIONS TO PERSIST THROUGH MOST
OF THE NIGHT. THIS MIXING WILL PREVENT TEMPS FROM REACHING THEIR
FULL COOLING POTENTIAL. MIN TEMPS INT HE 30-35 DEGREE RANGE.
THURSDAY...WE WILL REMAIN UNDER THE INFLUENCE OF THE UPPER LEVEL LOW
THOUGH THE ASSOCIATED SUBSIDENCE ON THE BACK SIDE SHOULD MAINTAIN
CLEAR SKIES OVER MOST OF THE REGION. NLY WINDS WILL GUSTS TO AROUND
25 KTS...ESPECIALLY IN THE MORNING...AND MAINLY EAST OF HIGHWAY 1.
850MB THERMAL TROUGH AND ASSOCIATED LOW LEVEL CAA WILL PERSIST
THROUGH THU. THIS YIELDS LOW LEVEL THICKNESSES ABOUT 25M BELOW
NORMAL. THIS WOULD SUGGEST MAX TEMPS ABOUT 6-9 DEGREES BELOW NORMAL.
FAVOR MAX TEMPS ABOUT 4 DEGREES BELOW GUIDANCE...RANGING FROM NEAR
50 FAR NE TO THE MID 50S SOUTH.
THURSDAY NIGHT...SURFACE HIGH PRESSURE WILL BEGIN TO INFLUENCE OUR
SENSIBLE WEATHER. PRESSURE GRADIENT ANALYSIS SUGGEST SOME POTENTIAL
FOR A LIGHT WIND THROUGH THE NIGHT. IF SFC WIND ABLE TO
DECOUPLE...COULD SEE TEMPS FALL ABOUT 3-4 DEGREES COOLER THAN
CURRENTLY FORECAST. FOR NOW...WILL MAINTAIN MIN TEMPS NEAR 30 TO
LOWER 30S. -WSS
&&
.SHORT TERM /FRIDAY AND FRIDAY NIGHT/...
AS OF 230 AM WEDNESDAY...
FRIDAY AND FRIDAY NIGHT:
VERTICALLY STACKED LOW PRESSURE SYSTEM IS EXPECTED TO CONTINUE TO
HANG AROUND SEVERAL HUNDRED MILES OFF THE MID ATLANTIC COAST ON
FRIDAY... BEFORE PICKING UP SOME EAST/EAST-SOUTHEASTWARD MOMENTUM ON
FRIDAY NIGHT AS ADDITIONAL S/W ENERGY IN THE FORM OF A BIT WEAKER
CLOSED LOW DIVES SOUTHEASTWARD FROM THE GREAT LAKES REGION THURSDAY
NIGHT INTO FRIDAY (BEFORE BEING ABSORBED BY THE DEEP CYCLONIC VORTEX
OFF THE MID ATLANTIC COAST LATE FRIDAY INTO FRIDAY NIGHT). THIS
ADDITIONAL ENERGY HAS TRENDED A BIT FURTHER WESTWARD WITH ITS
TRACK... YET STILL EXPECTED TO ONLY SIDE SWIPE OUR COASTAL PLAIN AND
NORTHEASTERN PIEDMONT COUNTIES FRIDAY INTO FRIDAY EVENING. GIVEN THE
OVERALL LACK OF MOISTURE EXPECTED ACROSS OUR AREA AND THE CURRENT
TRACK OF THE DISTURBANCE EXPECT WE SHOULD REMAIN DRY... WITH ONLY A
POSSIBLE INCREASE IN SOME CLOUD COVER ON FRIDAY AFTERNOON INTO THE
EVENING ACROSS EASTERN PORTIONS OF CENTRAL NC. HOWEVER... THE CLOUD
COVER COULD HAVE AN IMPACT ON HIGH TEMPERATURES FOR FRIDAY ACROSS
EASTERN/NORTHEASTERN PORTIONS OF THE RAH CWA. PLAN TO GO ON THE
COOLER SIDE OF GUIDANCE FOR MOST OF THE AREA AGAIN GIVEN THIS ALONG
WITH AFTERNOON LOW LEVEL THICKNESS VALUES EXPECTED TO RUN SOME 20 TO
30 METERS BELOW NORMAL FOR THIS TIME OF YEAR... PLUS A POSSIBLE SNOW
PACK TO THE NORTH OF THE CWA WITH CONTINUED NORTH-NORTHWESTERLY LOW
LEVEL FLOW. THIS YIELDS HIGH TEMPS FROM AROUND 50 NE TO THE UPPER
50S SW. IN ADDITION TO THE CHILLY TEMPS... EXPECT WE SHOULD CONTINUE
TO HAVE WINDS IN THE 10 TO 15 MPH RANGE... WITH GUSTS AS HIGH AS 25
MPH.
ANY CLOUD COVER ASSOCIATED WITH THE AFOREMENTIONED DISTURBANCE
SHOULD BEGIN TO SHIFT TO THE EAST OF THE AREA... WITH SUBSIDENCE IN
THE WAKE OF THE DISTURBANCE (NAM WOULD SUGGEST A BIT SLOWER TIMING
BUT APPEARS TO BE A SLOW OUTLIER WRT THE TIMING OF THE DISTURBANCE).
WITH SURFACE HIGH PRESSURE BUILDING INTO THE AREA AND CLEARING SKIES
EXPECT WE WILL SEE TEMPS FALL INTO THE UPPER 20S TO LOWER 30S FOR
LOWS SATURDAY MORNING... WITH A LIGHT NORTH-NORTHWESTERLY BREEZE
OVERNIGHT.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 3 AM WEDNESDAY...
S/W RIDGING IS EXPECTED TO BUILD ACROSS THE REGION FOR THE
WEEKEND... WHILE SURFACE HIGH PRESSURE MOVES ACROSS THE AREA AND
OFFSHORE. THIS WILL RESULT IN QUITE WEATHER ACROSS CENTRAL NC THIS
WEEKEND... WITH A WARMING TREND. EXPECT HIGH TEMPS ON SATURDAY WILL
BE IN THE MID TO UPPER 50S... WITH MAYBE A FEW LOCATIONS TOUCHING 60
ACROSS THE FAR SOUTH OR SOUTHWEST WITH MOSTLY SUNNY SKIES. HIGH
SUNDAY ARE EXPECTED TO BE EVEN WARMER... AS AFTERNOON LOW LEVEL
THICKNESS VALUES ARE EXPECTED TO FINALLY BE SLIGHTLY ABOVE NORMAL.
THUS... EXPECT HIGH TEMPS WILL WARM INTO THE LOWER TO MID 60S BY
SUNDAY AFTERNOON WITH INCREASING HIGH LEVEL CLOUD COVER. LOWS SUNDAY
MORNING ARE EXPECTED TO BE IN THE LOWER TO MID 30S... WITH EXCELLENT
RADIATIONAL COOLING CONDITIONS WITH MOSTLY CLEAR SKIES AND LIGHT AND
VARIABLE TO CALM WINDS AS HIGH PRESSURE ALOFT AND THE SURFACE WILL
SETTLE OVER THE AREA.
THE NEXT SYSTEM IS EXPECTED TO MOVE INTO THE AREA EARLY NEXT WEEK AS
A DEEP TROUGH AND ASSOCIATED COLD FRONT SHIFT EASTWARD AND
EVENTUALLY ACROSS THE REGION. THE OPERATIONAL GFS AND ECMWF HAVE
COME INTO MUCH BETTER AGREEMENT ON THE TIMING OF THE SYSTEM... AND
NOW BOTH SHOW AT LEAST SOME PHASING/INTERACTION OF THIS SYSTEM
(WHICH ORIGINATES FROM A CLOSED LOW IN THE SOUTHWESTERN U.S. LATE
THIS WEEK) WITH A NORTHERN STREAM TROUGH. BOTH THE 00Z ECMWF AND 00Z
GFS SHOW AN AREA OF SHOWERS AND POSSIBLY SOME THUNDERSTORMS MOVING
ACROSS THE AREA LATE MONDAY AFTERNOON INTO TUESDAY MORNING... ALONG
WITH THE PASSAGE OF A STRONG COLD FRONT BY TUESDAY MORNING. WPC
(FORMERLY KNOW AS HPC... NOW THE WEATHER PREDICTION CENTER) PREFERS
A BIT SLOWER TIMING... LAGGING THE TIMING OF THE FRONT AND CONTINUED
CHANCES FOR SHOWERS AND POSSIBLY STORMS INTO THE DAY TUESDAY... AS
THEY PREFER THE EUROPEAN CENTRE ENSEMBLE MEAN AS THEY NOTED IT
OUTSTANDING PERFORMANCE WITH THE SYNOPTIC FLOW OF LATE. THUS... WILL
TREND THE TIMING A BIT SLOWER THAN THE CURRENT OPERATIONAL MODELS
ADVERTISE... WITH A GOOD CHANCE OF RAIN STILL LATE MONDAY INTO
TUESDAY MORNING. EXPECT HIGHS TO BE IN THE 60S TO POSSIBLY 70S EAST
MONDAY... WITH UPPER 50S TO 60S TUESDAY (HIGHLY DEPENDENT ON THE
TIMING OF THE FRONT). LOWS EARLY NEXT WEEK ARE EXPECTED TO BE IN THE
40S TO EVEN AROUND 50 ON TUESDAY MORNING (AGAIN TIED TO THE EVENTUAL
TIMING OF THE FRONT).
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 1230 PM WEDNESDAY...
VFR CONDITIONS ARE EXPECTED TO PERSIST AT INT/GSO/FAY WELL INTO
WEDNESDAY. RDU/RWI WILL REMAIN CLOSER TO THE LOW CLOUD SHIELD (MVFR
TO HIGH-END IFR CIGS) ASSOCIATED WITH THE STRONG STORM CENTERED OVER
THE SE COAST OF VA... SO A PERIOD OF MVFR CIGS AND BRIEF MVFR VSBYS
WITHIN LIGHT RAIN SHOWERS (POSSIBLY MIXED WITH WET SNOW) ARE
POSSIBLE THIS AFTERNOON UNTIL 23Z-01Z. AS THIS STORM SYSTEM HEADS
OFF THE COAST THIS EVENING... SKIES WILL CLEAR OUT SW TO NE. STRONG
WINDS COMING FROM THE WEST AND NW WILL REMAIN AN AVIATION HAZARD
THROUGH EARLY TO MID EVENING... PRESENTING A SIGNIFICANT CROSSWIND
PRIMARILY AT GSO/RDU/RWI/FAY. SUSTAINED WINDS OF 15-25 KTS AND GUSTS
TO 30-38 KTS ARE EXPECTED THROUGH 22Z... THEN NW WINDS WILL BE
DIMINISHING THROUGH THE EVENING AS THEY BECOME NORTHERLY. UNLIMITED
SKIES AND NORTH WINDS 7-12 KTS ARE EXPECTED AFTER SUNRISE THURSDAY.
LOOKING BEYOND 18Z THURSDAY... VFR CONDITIONS WILL DOMINATE THROUGH
EARLY FRIDAY. BRIEF MVFR CIGS ARE POSSIBLE FRIDAY AFTERNOON INTO
FRIDAY NIGHT AS LOW PRESSURE MOVES BY TO OUR NORTHEAST. THEN AS A
STORM SYSTEM APPROACHES FROM THE WEST... IFR CIGS ARE POSSIBLE EARLY
MONDAY MORNING... LIFTING TO VFR BY MONDAY AFTERNOON.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR
NCZ007>011-021>028-038>043-073>078-083>086-088-089.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD/WSS
SHORT TERM...BSD
LONG TERM...BSD
AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
955 AM EST WED MAR 6 2013
.SYNOPSIS...
A POWERFUL LOW PRESSURE SYSTEM OVER SOUTHEAST VIRGINIA WILL MOVE
SLOWLY EAST OUT OVER THE ATLANTIC LATER TODAY THROUGH TONIGHT. DRY
HIGH PRESSURE WILL SLOWLY BUILD OVER THE EASTERN SEABOARD THURSDAY
THROUGH THE WEEKEND.
&&
.NEAR TERM /THROUGH THURSDAY NIGHT/...
AS OF 955 AM WEDNESDAY...
REST OF TODAY: STRONG GRADIENT WINDS AND THE CHANCE OF SNOW SHOWERS
OVER NORTH CENTRAL SECTIONS REMAIN SIGNIFICANT FORECAST CONCERNS.
LATEST SURFACE MAP SHOWS THE SURFACE LOW CENTER JUST NORTH OF
WILLIAMSBURG VA. MOSTLY LIGHT SNOW SHOWERS... OCCASIONALLY CHANGING
BACK TO RAIN WHEN RATES DECREASE... CONTINUE TO PIVOT OVER THE FAR
NORTH CENTRAL AND NORTHEAST CWA. WE`VE RECEIVED A FEW REPORTS OF
LIGHT ACCUMULATION ON GRASSY AREAS FROM A FEW SPOTS THIS MORNING...
AND THIS SEEMS TO HAVE BEEN THE CASE BENEATH THE AREAS OF HEAVIER
REFLECTIVITIES... ONE BAND OF WHICH IS PROGRESSING THROUGH FRANKLIN
TOWARD NASH COUNTY. WE ARE STILL CANVASSING THE COUNTIES AND TOWNS
THERE TO DETERMINE THE DEGREE OF IMPACT OF THE SNOW THAT HAS FALLEN
SO FAR... BUT BASED ON THE RADAR TRENDS AND RECENT HRRR RUNS WHICH
SUGGEST THAT SOME OF THE HEAVIER SNOW SHOWERS OVER SOUTH CENTRAL VA
MAY TRACK SOUTH OF THE BORDER... A SHORT-TERM ADVISORY MAY BE NEEDED
HERE. IN ANY CASE... BASED ON THE OBSERVED AND EXPECTED WET BULB
TEMPS THAT SHOULD HOLD VERY CLOSE TO FREEZING OR JUST ABOVE... AND
WITH FAIRLY MILD ROAD TEMPS... ROADS SHOULD BE JUST WET WITH ANY
ACCUMULATION ON THE GRASSY AREAS ONLY. WILL CONTINUE TO MONITOR. THE
WIND ADVISORY WILL REMAIN AS IS. SEVERAL GUSTS OVER 30 KTS HAVE
ALREADY BEEN REPORTED... PRIMARILY IN LOCATIONS THAT HAVE SEEN SOME
SUNSHINE THIS MORNING... IN THE FAR WEST AND ACROSS THE SOUTHERN
CWA. OBSERVED 925 MB TEMPS FROM UPPER AIR SOUNDINGS ARE AROUND 30
KTS... AND AROUND 35-40 KT AT 850 MB... SO WITH GOOD MIXING EXPECT
FREQUENT GUSTS TO AROUND 35-45 MPH. HIGHS FROM 36-40 NORTH TO AROUND
50 IN THE SOUTH. -GIH
TONIGHT...SHOULD SEE PRECIP CHANCES END EARLY IN THE FAR NE AS THE
LOW PRESSURE SYSTEM PULLS FARTHER AWAY. CLEARING SKIES WILL TREND
EWD DURING THE NIGHT. DUE TOT HE LARGE WIND FIELD ASSOCIATED WITH
THE SYSTEM...EXPECT WINDY/BREEZY CONDITIONS TO PERSIST THROUGH MOST
OF THE NIGHT. THIS MIXING WILL PREVENT TEMPS FROM REACHING THEIR
FULL COOLING POTENTIAL. MIN TEMPS INT HE 30-35 DEGREE RANGE.
THURSDAY...WE WILL REMAIN UNDER THE INFLUENCE OF THE UPPER LEVEL LOW
THOUGH THE ASSOCIATED SUBSIDENCE ON THE BACK SIDE SHOULD MAINTAIN
CLEAR SKIES OVER MOST OF THE REGION. NLY WINDS WILL GUSTS TO AROUND
25 KTS...ESPECIALLY IN THE MORNING...AND MAINLY EAST OF HIGHWAY 1.
850MB THERMAL TROUGH AND ASSOCIATED LOW LEVEL CAA WILL PERSIST
THROUGH THU. THIS YIELDS LOW LEVEL THICKNESSES ABOUT 25M BELOW
NORMAL. THIS WOULD SUGGEST MAX TEMPS ABOUT 6-9 DEGREES BELOW NORMAL.
FAVOR MAX TEMPS ABOUT 4 DEGREES BELOW GUIDANCE...RANGING FROM NEAR
50 FAR NE TO THE MID 50S SOUTH.
THURSDAY NIGHT...SURFACE HIGH PRESSURE WILL BEGIN TO INFLUENCE OUR
SENSIBLE WEATHER. PRESSURE GRADIENT ANALYSIS SUGGEST SOME POTENTIAL
FOR A LIGHT WIND THROUGH THE NIGHT. IF SFC WIND ABLE TO
DECOUPLE...COULD SEE TEMPS FALL ABOUT 3-4 DEGREES COOLER THAN
CURRENTLY FORECAST. FOR NOW...WILL MAINTAIN MIN TEMPS NEAR 30 TO
LOWER 30S. -WSS
&&
.SHORT TERM /FRIDAY AND FRIDAY NIGHT/...
AS OF 230 AM WEDNESDAY...
FRIDAY AND FRIDAY NIGHT:
VERTICALLY STACKED LOW PRESSURE SYSTEM IS EXPECTED TO CONTINUE TO
HANG AROUND SEVERAL HUNDRED MILES OFF THE MID ATLANTIC COAST ON
FRIDAY... BEFORE PICKING UP SOME EAST/EAST-SOUTHEASTWARD MOMENTUM ON
FRIDAY NIGHT AS ADDITIONAL S/W ENERGY IN THE FORM OF A BIT WEAKER
CLOSED LOW DIVES SOUTHEASTWARD FROM THE GREAT LAKES REGION THURSDAY
NIGHT INTO FRIDAY (BEFORE BEING ABSORBED BY THE DEEP CYCLONIC VORTEX
OFF THE MID ATLANTIC COAST LATE FRIDAY INTO FRIDAY NIGHT). THIS
ADDITIONAL ENERGY HAS TRENDED A BIT FURTHER WESTWARD WITH ITS
TRACK... YET STILL EXPECTED TO ONLY SIDE SWIPE OUR COASTAL PLAIN AND
NORTHEASTERN PIEDMONT COUNTIES FRIDAY INTO FRIDAY EVENING. GIVEN THE
OVERALL LACK OF MOISTURE EXPECTED ACROSS OUR AREA AND THE CURRENT
TRACK OF THE DISTURBANCE EXPECT WE SHOULD REMAIN DRY... WITH ONLY A
POSSIBLE INCREASE IN SOME CLOUD COVER ON FRIDAY AFTERNOON INTO THE
EVENING ACROSS EASTERN PORTIONS OF CENTRAL NC. HOWEVER... THE CLOUD
COVER COULD HAVE AN IMPACT ON HIGH TEMPERATURES FOR FRIDAY ACROSS
EASTERN/NORTHEASTERN PORTIONS OF THE RAH CWA. PLAN TO GO ON THE
COOLER SIDE OF GUIDANCE FOR MOST OF THE AREA AGAIN GIVEN THIS ALONG
WITH AFTERNOON LOW LEVEL THICKNESS VALUES EXPECTED TO RUN SOME 20 TO
30 METERS BELOW NORMAL FOR THIS TIME OF YEAR... PLUS A POSSIBLE SNOW
PACK TO THE NORTH OF THE CWA WITH CONTINUED NORTH-NORTHWESTERLY LOW
LEVEL FLOW. THIS YIELDS HIGH TEMPS FROM AROUND 50 NE TO THE UPPER
50S SW. IN ADDITION TO THE CHILLY TEMPS... EXPECT WE SHOULD CONTINUE
TO HAVE WINDS IN THE 10 TO 15 MPH RANGE... WITH GUSTS AS HIGH AS 25
MPH.
ANY CLOUD COVER ASSOCIATED WITH THE AFOREMENTIONED DISTURBANCE
SHOULD BEGIN TO SHIFT TO THE EAST OF THE AREA... WITH SUBSIDENCE IN
THE WAKE OF THE DISTURBANCE (NAM WOULD SUGGEST A BIT SLOWER TIMING
BUT APPEARS TO BE A SLOW OUTLIER WRT THE TIMING OF THE DISTURBANCE).
WITH SURFACE HIGH PRESSURE BUILDING INTO THE AREA AND CLEARING SKIES
EXPECT WE WILL SEE TEMPS FALL INTO THE UPPER 20S TO LOWER 30S FOR
LOWS SATURDAY MORNING... WITH A LIGHT NORTH-NORTHWESTERLY BREEZE
OVERNIGHT.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 3 AM WEDNESDAY...
S/W RIDGING IS EXPECTED TO BUILD ACROSS THE REGION FOR THE
WEEKEND... WHILE SURFACE HIGH PRESSURE MOVES ACROSS THE AREA AND
OFFSHORE. THIS WILL RESULT IN QUITE WEATHER ACROSS CENTRAL NC THIS
WEEKEND... WITH A WARMING TREND. EXPECT HIGH TEMPS ON SATURDAY WILL
BE IN THE MID TO UPPER 50S... WITH MAYBE A FEW LOCATIONS TOUCHING 60
ACROSS THE FAR SOUTH OR SOUTHWEST WITH MOSTLY SUNNY SKIES. HIGH
SUNDAY ARE EXPECTED TO BE EVEN WARMER... AS AFTERNOON LOW LEVEL
THICKNESS VALUES ARE EXPECTED TO FINALLY BE SLIGHTLY ABOVE NORMAL.
THUS... EXPECT HIGH TEMPS WILL WARM INTO THE LOWER TO MID 60S BY
SUNDAY AFTERNOON WITH INCREASING HIGH LEVEL CLOUD COVER. LOWS SUNDAY
MORNING ARE EXPECTED TO BE IN THE LOWER TO MID 30S... WITH EXCELLENT
RADIATIONAL COOLING CONDITIONS WITH MOSTLY CLEAR SKIES AND LIGHT AND
VARIABLE TO CALM WINDS AS HIGH PRESSURE ALOFT AND THE SURFACE WILL
SETTLE OVER THE AREA.
THE NEXT SYSTEM IS EXPECTED TO MOVE INTO THE AREA EARLY NEXT WEEK AS
A DEEP TROUGH AND ASSOCIATED COLD FRONT SHIFT EASTWARD AND
EVENTUALLY ACROSS THE REGION. THE OPERATIONAL GFS AND ECMWF HAVE
COME INTO MUCH BETTER AGREEMENT ON THE TIMING OF THE SYSTEM... AND
NOW BOTH SHOW AT LEAST SOME PHASING/INTERACTION OF THIS SYSTEM
(WHICH ORIGINATES FROM A CLOSED LOW IN THE SOUTHWESTERN U.S. LATE
THIS WEEK) WITH A NORTHERN STREAM TROUGH. BOTH THE 00Z ECMWF AND 00Z
GFS SHOW AN AREA OF SHOWERS AND POSSIBLY SOME THUNDERSTORMS MOVING
ACROSS THE AREA LATE MONDAY AFTERNOON INTO TUESDAY MORNING... ALONG
WITH THE PASSAGE OF A STRONG COLD FRONT BY TUESDAY MORNING. WPC
(FORMERLY KNOW AS HPC... NOW THE WEATHER PREDICTION CENTER) PREFERS
A BIT SLOWER TIMING... LAGGING THE TIMING OF THE FRONT AND CONTINUED
CHANCES FOR SHOWERS AND POSSIBLY STORMS INTO THE DAY TUESDAY... AS
THEY PREFER THE EUROPEAN CENTRE ENSEMBLE MEAN AS THEY NOTED IT
OUTSTANDING PERFORMANCE WITH THE SYNOPTIC FLOW OF LATE. THUS... WILL
TREND THE TIMING A BIT SLOWER THAN THE CURRENT OPERATIONAL MODELS
ADVERTISE... WITH A GOOD CHANCE OF RAIN STILL LATE MONDAY INTO
TUESDAY MORNING. EXPECT HIGHS TO BE IN THE 60S TO POSSIBLY 70S EAST
MONDAY... WITH UPPER 50S TO 60S TUESDAY (HIGHLY DEPENDENT ON THE
TIMING OF THE FRONT). LOWS EARLY NEXT WEEK ARE EXPECTED TO BE IN THE
40S TO EVEN AROUND 50 ON TUESDAY MORNING (AGAIN TIED TO THE EVENTUAL
TIMING OF THE FRONT).
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
AS OF 655 AM WEDNESDAY...
CEILINGS HAVE IMPROVED ACROSS MUCH OF CENTRAL NC SINCE 3 AM WITH
MOST LOCALES IN THE WEST INCLUDING KINT AND KGSO REPORTING VFR
CEILINGS. ACROSS THE EAST...CEILINGS STILL MVFR BUT SHOULD GRADUALLY
LIFT TO HIGH END MVFR/LOW END VFR BY 15-18Z. SCATTERED RAIN AND/OR
SNOW SHOWERS WILL ROTATE EWD ACROSS THE REGION THIS MORNING...AND
MAINLY ACROSS THE NE PIEDMONT AND NORTHERN COASTAL PLAIN THIS
AFTERNOON.
VERY WINDY CONDITIONS WILL OCCUR SHORTLY AS A DEEP LOW PRESSURE
SYSTEM MOVES EWD AND TAKES A POSITION JUST OFF THE VA-NC COAST. SFC
WINDS WILL VEER TO A MORE NW DIRECTION WITH SUSTAINED WINDS NEAR
20KTS AND FREQUENT GUSTS AROUND 40KTS. A SPORADIC GUST NEAR 50KTS
CANNOT BE RULED OUT. THESE WINDS MAY CAUSE CROSSWIND ISSUES AT
SEVERAL TERMINALS TODAY.
THE STRONG UPPER LEVEL LOW WILL SLOWLY TRAVERSE EWD TONIGHT THROUGH
THU. SUBSIDENCE BEHIND THE DEPARTING LOW WILL AID TO
DIMINISH/DISSIPATE THE CLOUD COVER WEST-TO-EAST. WHILE CLOUDS WILL
DEPART LATER TONIGHT...WINDY CONDITIONS WILL LINGER WELL INTO
TONIGHT WITH BREEZY CONDITIONS LIKELY ON THURSDAY. THE BREEZY
CONDITIONS SHOULD ABATE BY THU NIGHT AS HIGH PRESSURE BEGINS TO
EXERT ITS INFLUENCE. VFR CONDITIONS EXPECTED ACROSS THE REGION LATER
TONIGHT AND PERSISTING INTO SUNDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR
NCZ007>011-021>028-038>043-073>078-083>086-088-089.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD/WSS
SHORT TERM...BSD
LONG TERM...BSD
AVIATION...WSS
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1239 AM EST WED MAR 6 2013
.SYNOPSIS...
A POTENT STORM SYSTEM WILL CROSS THE AREA TONIGHT...BRINGING SHOWERS
AND PERHAPS A RUMBLE OF THUNDER. COLDER AIR RETURNS ALONG WITH
STRONG GUSTY WINDS WEDNESDAY INTO THURSDAY AS THIS STORM SYSTEM
LIFTS OFF TO THE NORTHEAST. THE LATE WEEK PERIOD WILL FEATURE A
RETURN OF SEASONABLE TEMPERATURES.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 12:30 AM WEDNESDAY...SHOWERS HAVE ENDED FOR THE NIGHT AS
RAIN-SHIELD MOVES OFFSHORE. HAVE UPDATED FORECAST ACCORDINGLY.
COLD FRONT WILL BE MOVING OFFSHORE SHORTLY. NO OTHER CHANGES TO
THE FORECAST WITH THE LATEST UPDATE. WIND ADVISORY REMAINS IN
EFFECT. PREVIOUS DISCUSSION FOLLOWS:
A POWERFUL UPPER LEVEL LOW IS STILL STRENGTHENING AS IT MOVES EAST
ACROSS SOUTHERN KENTUCKY THIS EVENING AND TOWARD NORTHERN NORTH
CAROLINA WEDNESDAY MORNING. SURFACE LOW PRESSURE CENTERED OVER
SOUTHERN OHIO IS OCCLUDING AS A NEW CENTER DEVELOPING OVER THE NC
WESTERN PIEDMONT BECOMES THE DOMINANT LOW. A COLD FRONT SOUTH OF
THIS DEVELOPING LOW EXTENDS FROM NEAR MONROE NC SOUTH THROUGH
COLUMBIA AND INTO EASTERN GEORGIA.
SHOWERS AND EMBEDDED THUNDERSTORMS HAVE ACCOMPANIED THE COLD FRONT
ACROSS GEORGIA AND INTO THE CAROLINAS THIS EVENING. THERMODYNAMIC
CONDITIONS WERE MUCH MORE FAVORABLE FOR UPRIGHT CONVECTION ACROSS
GEORGIA AND THE WESTERN HALF OF SOUTH CAROLINA EARLIER. AS THE LINE
HAS MOVED INTO THE EASTERN CAROLINAS SURFACE CAPE IS ZERO...WHILE
PARCELS LIFTED FROM 875 MB CONTAIN MEAGER INSTABILITY ESTIMATED BY
THE LATEST RUC AT 100 J/KG OR LESS. BULK SHEAR THROUGH THE 0-6 KM
LAYER IS EXTREME (60-70 KT) WHICH IS PROBABLY TOO MUCH GIVEN THE
MEAGER INSTABILITY...RESULTING IN ANY UPDRAFTS GETTING DILUTED BY
THE ENVIRONMENT. WHILE I AM MAINTAINING HIGH POPS FOR MEASURABLE
PRECIP THIS EVENING...ACTUAL GAUGE-MEASURED RAINFALL AMOUNTS SHOULD
REMAIN QUITE LOW: 0.05 TO 0.15 INCHES FOR MOST AREAS.
AFTER THE FRONT SWEEPS OFFSHORE SHORTLY AFTER MIDNIGHT MUCH COLDER
AIR WILL SURGE INTO THE AREA. THE CHANGE IN AIRMASS IS VERY SUDDEN:
850 MB TEMPS SHOULD FALL FROM +7C AT 00Z TO -5C AT 12Z...
ACCOMPANIED BY SIMILAR EXTREME CHANGES IN LAYER THICKNESS VALUES AND
MID-LEVEL HEIGHTS. AS THE UPPER LOW MAKES ITS CLOSEST APPROACH TO
THE AREA WEDNESDAY AFTERNOON THE TROPOPAUSE SHOULD ACTUALLY LOWER
TO JUST ABOVE 500 MB OR ABOUT 19000 FT AGL. THIS IS WELL BELOW
TYPICAL VALUES AND SHOWS JUST HOW POWERFUL THIS SYSTEM IS. FORECAST
SOUNDINGS FROM THE RUC...NAM AND GFS SHOW DRY ADIABATIC LAPSE RATES
DEVELOPING THROUGH THE LOWEST SEVERAL THOUSAND FEET OF THE
ATMOSPHERE BY 09Z (4 AM WEDNESDAY) AS COLD ADVECTION STRENGTHENS.
WIND SPEEDS JUST 1000 FT AGL SHOULD INCREASE TO 30 KNOTS...AND TO
NEARLY 40 KNOTS AT 2000 FT AGL. THIS MOMENTUM WILL WORK ITS WAY DOWN
IN GUSTS LATE TONIGHT AND ESPECIALLY WEDNESDAY AFTER THE SUN RISES
AND LAPSE RATES ARE FORCED TO BECOME DRY ADIABATIC OVER AN EVEN
DEEPER LAYER. THE WIND ADVISORY RAISED EARLIER TODAY APPEARS TO BE
AN EXCELLENT CALL!
LOW TEMPERATURES TONIGHT SHOULD FALL TO AROUND 40 INLAND WITH MID
40S AT THE COAST...ALL WITH A DEEPLY MIXED ATMOSPHERE PREVENTING ANY
HINT OF A RADIATIONAL INVERSION.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH THURSDAY NIGHT/...
AS OF 3 PM TUESDAY...STRONG LOW PRESSURE SYSTEM OVER THE MID
ATLANTIC COAST EARLY WED MORNING WILL BE MOVE SLOWLY OFF THE COAST
THROUGH THE PERIOD AS STRONG HIGH PRESSURE BUILDS IN BEHIND IT. A
VERY TIGHT GRADIENT WILL EXIST BETWEEN THE TWO SYSTEMS THROUGH WED
INTO THURS WITH DEEP LAYER W-NW WINDS ADVECTING IN VERY DRY AND
COOL AIR ON BACK END OF LOW. EXPECT STRONG AND GUSTY WESTERLY
WINDS INITIALLY ON WED BECOMING NORTHWEST ON THURS. WINDS WILL BE
STRONGEST OVER COASTAL NORTH CAROLINA WHERE WINDS WILL RUN BETWEEN
20 TO 30 MPH WITH GUSTS UP TO 45 MPH. WILL ISSUE WIND ADVISORY FOR
WEDNESDAY.
COLD AND DRY ADVECTION WILL CONTINUE THROUGH WED INTO THURS ON THE
BACK END OF THE LOW. PCP WATER VALUES DROP DOWN TO LESS THAN A
QUARTER OF AN INCH AS DRY SLOT WRAPPING AROUND LOW MOVES INTO
AREA. A POTENT VORT MAX ROTATES AROUND THE LOW THROUGH WED AFTN
INTO EARLY EVENING OVER THE CAROLINAS. THIS WILL PRODUCE THE
POTENTIAL FOR CLOUDS BUT FOR NOW WILL KEEP PCP OUT OF FORECAST
WITH WESTERLY DOWNSLOPE FLOW THROUGH WED AFTN. POTENTIAL INCREASES
THROUGH WED AFTERNOON. MODELS SHOW PCP WATER VALUES REACHING UP TO
A HALF INCH REACHING INTO NORTHERN TIER COUNTIES OF CWA...BUT FOR
THE MOST PART THE BEST CHC OF ANY PCP WILL BE NORTH OF AREA.
TEMPS WILL BE SOMEWHAT CHALLENGING AS OVERNIGHT LOWS HEADING INTO
WED WILL BE ON THE WARM SIDE...UP AROUND 50 AT DAYBREAK. BUT THEN
PLENTY OF COOL AIR WILL RUSH IN FIRST FEW HOURS OF DAYBREAK.
EXPECT HIGHEST TEMP FOR WED TO OCCUR JUST AROUND MIDNIGHT AND
AFTERNOON TEMPS TO BE CLOSER TO 50. 850 TEMPS BOTTOM OUT RIGHT
AROUND NOON ON WED WITH -5C. TEMPS WILL DROP INTO THE 30S IN CAA
THROUGH WED NIGHT AND THEREFORE EXPECT TEMPS ON THE COOL SIDE
AGAIN FOR THURS. WILL UNDERCUT GUIDANCE AND KEEP WITH LOWER 50S
MOST PLACES ON THURS.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 300 PM TUESDAY...QUIET WEATHER FOR MUCH OF THE EXTENDED WITH
TEMPS WARMING TO...POTENTIALLY...WELL ABOVE NORMAL EARLY NEXT WEEK.
A COLD FRONT WILL APPROACH AT THE END OF THE PERIOD...BRINGING THE
ONLY CHANCE FOR PRECIP.
LARGE LOW PRESSURE OFF THE NEW ENGLAND COAST AND A RIDGE OF HIGH
PRESSURE BUILDING DOWN FROM THE NW WILL KEEP COOL NORTHERLY FLOW
ACROSS THE CAROLINAS FRIDAY. THE LOW PRESSURE WILL PUSH OFF TO THE
EAST BY SATURDAY AS HIGH PRESSURE RIDGES DOWN TO THE GULF COAST
THROUGH THE WKND...BECOMING CENTERED OVERHEAD SUNDAY. ALTHOUGH THIS
KEEPS LIGHT NORTH WINDS AND WEAK CAA...TEMPS WILL GRADUALLY WARM
FROM MID/UPPER 50S FRIDAY...INTO THE MID 60S SUNDAY THANKS TO THE
LIGHTER WINDS AND FULL MARCH INSOLATION. AS HIGH PUSHES OFFSHORE
MON/TUE...RETURN FLOW PUMPS MUCH WARMER AIR INTO THE REGION WITH
TEMPS RISING TO WELL ABOVE NORMAL...APPROACHING 70 BOTH
DAYS...ALTHOUGH HIGH LEVEL CLOUD COVER WILL BE ON THE INCREASE NEXT
WEEK. MINS THROUGH THE PERIOD WILL GRADUALLY INCREASE AS WELL...FROM
MID 30S FRIDAY NIGHT...TO UPPER 40S MON NIGHT.
GUIDANCE SUGGESTS A COLD FRONT WILL CROSS EARLY TUESDAY...BUT EXPECT
THIS TO BE SLOWED BY THE ANTECEDENT RIDGING AND INCREASINGLY
BOUNDARY-PARALLEL MID LEVEL FLOW. DECENT THETA-E RIDGING AHEAD OF
THIS FEATURE WILL SUPPORT SHOWERS TUESDAY...BUT BEING D7 AND
EXPECTED SLOWING OF BOUNDARY WILL CARRY ONLY SCHC/SILENT FOR NOW ON
TUE.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
AS OF 06Z...FRONT PROBABLY THROUGH FLO AND LBT AND WILL PUSH
OFFSHORE SHORTLY AFTER TAF ISSUANCE. WINDS WILL SHIFT WESTERLY
WITH MODERATE TO STRONG COLD AIR ADVECTION COMMENCING TOWARD
MORNING. STRONG MIXING AND GRADIENT WILL KICK WINDS WELL INTO THE
30 KT RANGE BY MIDDAY. MOISTURE ROTATION AROUND THE STRONG LOW
NORTH OF HERE...ALONG WITH COLD AIR ALOFT...WILL CREATE A STRATA
CU CEILING MAINLY NORTH OF THE REGION...BUT LBT AND ILM MAY GET
INTO THE ACT. LOOK FOR WINDS TO DIMINISH AFTER SUNSET...SETTLING
DOWN THE MOST AT THE SOUTHERN TERMINALS WHERE THE GRADIENT IS
RELATIVELY WEAKER.
EXTENDED OUTLOOK...VFR CONDITIONS SHOULD PREVAIL THROUGH SUNDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 12:30 AM WEDNESDAY...NO SIGNIFICANT CHANGES HAVE BEEN MADE TO
THE MARINE FORECAST THIS EVENING. GALE WARNING REMAINS IN EFFECT
FOR DANGEROUSLY STRONG WINDS AND HIGH SEAS ASSOCIATED WITH A
STRONG FRONTAL SYSTEM THAT WILL SOON MOVE OFFSHORE. PREVIOUS
DISCUSSION FOLLOWS:
SOUTHWEST WINDS ARE STEADILY INCREASING AHEAD OF A STRONG COLD FRONT
NOW PUSHING INTO THE WESTERN CAROLINAS. THIS FRONT WILL RAPIDLY MOVE
EAST AND ACROSS THE COASTAL WATERS AFTER MIDNIGHT...ACCOMPANIED BY A
LINE OF SHOWERS AND ISOLATED THUNDERSTORMS. BEHIND THE FRONT SURFACE
PRESSURES WILL RISE RAPIDLY WHICH SHOULD RESULT IN THE ONSET OF
GALE-FORCE WINDS...AT LEAST IN GUSTS...SEVERAL HOURS BEFORE SUNRISE.
MODELS ARE IN EXCELLENT AGREEMENT WITH THE TIMING AND ANTICIPATED
HIGH IMPACT OF THIS SYSTEM TO MARINERS. NO SIGNIFICANT CHANGES HAVE
BEEN MADE TO THE FORECAST WITH THIS EARLY EVENING UPDATE.
SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 3 PM TUESDAY...POTENT LOW PRESSURE SYSTEM WILL BE MOVING
SLOWLY OFF THE MID ATLANTIC COAST THROUGH PERIOD. A VERY TIGHT
GRADIENT WILL EXIST BETWEEN THIS LOW AND STRONG HIGH PRESSURE
BUILDING IN ON THE BACK END. TIGHTENED GRADIENT FLOW COMBINED WITH
COLD SURGE ON BACK END OF LOW WILL PRODUCE STRONG GUSTY WESTERLY
WINDS UP TO 35 KTS WITH HIGHER GUSTS THROUGH WED. A GALE WARNING WILL
REMAIN IN EFFECT INTO WED EVENING.
MAX SEAS WILL BE WED MORNING UP AROUND 7 TO 10 FT WITH HIGHER SEAS
JUST OUTSIDE OF LOCAL WATERS. THE OFF SHORE FLOW WILL ALLOW NEAR
SHORE SEAS TO SUBSIDE BY THE END OF WED BUT STILL EXPECT 6 TO 8 FT
SEAS THROUGH WED EVENING. EXPECT A SLOW DECREASE IN SPEEDS HEADING
INTO THURSDAY AS THE LOW PRESSURE SYSTEM MOVES FURTHER OFF THE
MID ATLANTIC COAST. SEAS WILL CONTINUE TO SUBSIDE IN SLOWLY
WEAKENING OFF SHORE FLOW. EXPECT SEAS DOWN BELOW SCA BY DAYBREAK
THURSDAY WITH HEIGHTS AROUND 4 TO 5 FT IN OUTER WATERS AND LESS
THAN 3 FT NEAR SHORE. BY THURSDAY EVENING EXPECT SEAS 2-4 FEET
ACROSS THE WATERS.
LONG TERM /FRIDAY THROUGH SUNDAY/...
AS OF 300 PM TUESDAY...VERY LARGE LOW PRESSURE MOVING SLOWLY OFF THE
NEW ENGLAND COAST WILL KEEP A PINCHED GRADIENT WITH WINDS VEERING
FROM NW TO NORTH THROUGH FRIDAY. WINDS WILL BE 15-20 KTS...WITH
GUSTS UP TO 30 KTS DURING THE DAY. ALTHOUGH THIS IS PRIMARILY AN
OFFSHORE DIRECTION...SEAS WILL REMAIN ELEVATED AT 2-5 FT.
HOWEVER...AS WINDS BECOME SLIGHTLY MORE NORTHERLY LATE FRIDAY...WAVE
HEIGHTS NEAR THE 20NM BOUNDARY OF AMZ250 AND AMZ252 MAY APPROACH
6FT...AND A SHORT SMALL CRAFT ADVISORY MAY BE NEEDED FRIDAY NIGHT
THROUGH SATURDAY MORNING. SEAS THROUGH SATURDAY WILL BE FORMED VIA A
COMBINATION OF NORTHERLY WIND WAVES...AND AN EASTERLY BACK SWELL OF
2-4 FT AT 13 SEC.
HIGH PRESSURE BUILDS DOWN ACROSS THE AREA FROM THE NW SAT/SUN
CAUSING WINDS TO SHIFT SLOWLY FROM NORTH TO SE BY LATE SUNDAY...WITH
SPEEDS DECREASING TO LESS THAN 10 KTS DUE TO THE RELAXED GRADIENT.
SEAS RESPOND ONLY SLOWLY WITH A 2-4 FT EASTERLY BACKSWELL PERSISTING
WITHIN THE SPECTRUM. STILL...SEAS WILL FALL THROUGH THE
WKND...BECOMING 2-4 FT ON SUNDAY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...WIND ADVISORY UNTIL 6 PM EST THIS EVENING FOR SCZ017-023-024-
032-033-039-053>056.
NC...WIND ADVISORY UNTIL 6 PM EST THIS EVENING FOR NCZ087-096-099-
105>110.
MARINE...GALE WARNING UNTIL 6 PM EST THIS EVENING FOR AMZ250-252-254-
256.
&&
$$
NEAR TERM...REK/RJD
SHORT TERM...RGZ
LONG TERM...JDW
AVIATION...DL
MARINE...REK/RJD/JDW/RGZ
AREA FORECAST DISCUSSION
NWS BISMARCK ND
348 AM CST WED MAR 6 2013
.SHORT TERM...TODAY THROUGH THURSDAY...
THE MAIN CHALLENGE FOR THE SHORT TERM IS THE EVOLUTION OF THE
STRATUS TODAY WITH DENSE FOG NORTH CENTRAL ALSO HIGHLIGHTING THE
PERIOD THIS MORNING. THE 00 UTC GUIDANCE IS IN GOOD AGREEMENT AND
FAVORED A BLEND FOR MOST FIELDS WITH BIAS CORRECTION PREFERRED FOR
HIGH TEMPERATURES TO CAPTURE THE IMPACT OF THE SNOWPACK. THE MAIN
CORRECTION BEING A REDUCTION OF A COUPLE DEGREES NORTH CENTRAL AND
AN INCREASE OF A FEW DEGREES SOUTHWEST AND SOUTH CENTRAL.
MAINTAINED THE DENSE FOG ADVISORY THROUGH 15 UTC ACROSS NORTH
CENTRAL NORTH DAKOTA AS SURFACE OBSERVATIONS AND WEBCAMS CONTINUE
TO INDICATE WIDESPREAD DENSE FOG WITH VISIBILITIES OF ONE QUARTER
MILE OR LESS IN THE STRATUS FREE AREAS AS OF 0930 UTC. AS MIXING
INCREASES IN THE 12-15 UTC TIME FRAME IN RETURN FLOW ON THE WESTERN
PERIPHERY OF THE DEPARTING SURFACE HIGH...THE FOG SHOULD QUICKLY
LIFT.
OTHERWISE FOR TODAY AS IS USUALLY THE CASE WITH STRATUS...THE
QUESTION IS HOW LONG IT WILL REMAIN IN PLACE. THE RAP THROUGH THE
OVERNIGHT HAS HAD A GOOD HANDLE ON THE DECKS ACROSS WESTERN
THROUGH SOUTH CENTRAL NORTH DAKOTA AND ACROSS THE EASTERN PORTIONS
OF THE STATE. THUS...WILL FOLLOW ITS LATEST RUNS FOR CLOUD COVER
TODAY...WHICH HOLDS THE STRATUS FIELDS THROUGH THE MORNING AND
SLOWLY LIFTS THEM THROUGH THE AFTERNOON. DID ADD A MENTION OF
ISOLATED FLURRIES UNDER THE STRATUS BASED ON OBSERVED TRENDS UNDER
THE DECK THROUGH THE NIGHT. WITH SOUTHEASTERLY WINDS...A LOW LEVEL
INVERSION WILL SETUP ACROSS THE AREA...LIMITING MIXING HEIGHTS AND
HIGH TEMPERATURES. GIVEN THE COLD START NORTH CENTRAL THIS MORNING
AND THE FRESH SNOW...HIGHS ARE ONLY EXPECTED TO CLIMB INTO THE
TEENS. ACROSS THE THINNER SNOWPACK OF THE SOUTHWEST...BELIEVE
HIGHS IN THE LOWER 30S ARE POSSIBLE ACROSS THE HIGHER TERRAIN AS
MORE AND MORE BARE GROUND BECOMES EXPOSED THROUGH THE DAY.
FOR TONIGHT...A TIGHT PRESSURE GRADIENT BETWEEN THE AFOREMENTIONED
DEPARTING HIGH AND LOW PRESSURE ACROSS NORTHEAST WYOMING WILL
MAINTAIN SOUTHEASTERLY WINDS AROUND 15 KTS FOR MUCH OF THE AREA
OVERNIGHT. THUS...TEMPERATURES SHOULD NOT FALL TOO FAR...WITH LOWS
NEAR 10 NORTHEAST TO THE UPPER 20S SOUTHWEST.
ON THURSDAY A WARM FRONT PROPAGATES INTO WESTERN NORTH DAKOTA AND
IS FORECAST TO MAKE IT THROUGH THE HIGHWAY 83 CORRIDOR BY LATE
AFTERNOON. FAVORING BIAS CORRECTION TO AID IN THE SNOWPACK
IMPACTS...HIGHS SHOULD RANGE FROM THE MID 20S ACROSS THE TURTLE
MOUNTAINS TO UPPER 30S SOUTH CENTRAL AND POSSIBLY THE LOWER 40S
SOUTHWEST AS INSOLATION FROM TODAY...BREEZY CONDITIONS THROUGH THE
OVERNIGHT AND MILD TEMPERATURES ON THURSDAY SHOULD ALL ACT TO
QUICKLY EVAPORATE/MELT THE SNOW ACROSS THE SOUTHWEST AND SOUTH
CENTRAL. THERE IS A SLIGHT CHANCE OF SNOW MAINLY ALONG AND NORTH
OF US HIGHWAY 2 ON THURSDAY AS AN UPPER LEVEL WAVE EJECTS OUT OF
THE INTERMOUNTAIN WEST. HOWEVER...THE 00 UTC GUIDANCE HAS TRENDED
FURTHER NORTH WITH ANY PRECIPITATION COMPARED TO EARLIER RUNS.
LONG TERM...THURSDAY NIGHT THROUGH TUESDAY...
THE MAIN FOCUS OF THE LONG TERM PERIOD IS THE POTENTIAL FOR ANOTHER
ROUND OF SNOW ON FRIDAY...POSSIBLY LINGERING INTO SATURDAY. MODEL
CONSENSUS IS STRONGER TODAY WITH THE LATEST SUITE OF
MODELS...REGARDING THE EVOLUTION OF A LARGE WESTERN CONUS TROUGH
THROUGH THE PLAINS. CONFIDENCE IS INCREASING IN THE POTENTIAL FOR
LIGHT SNOW FRIDAY AFTERNOON AND NIGHT...MAINLY OVER SOUTHERN AND
CENTRAL PORTIONS OF THE FORECAST AREA. LATEST WPC GUIDANCE AROUND A
COUPLE INCHES THROUGH 12Z SATURDAY SEEMS REASONABLE AT THIS POINT.
THERE IS STILL UNCERTAINTY AS TO HOW FAST THE TROUGH WILL EXIT ON
SATURDAY...AS THE ECMWF/GFS ARE FASTER AND THE GEM/NAM SUGGEST
ADDITIONAL SNOW ACROSS THE SOUTHEAST. HAVE OPTED TO STICK WITH THE
FASTER SOLUTIONS AND KEEP CHC POPS LIMITED TO THE FAR SE COUNTIES ON
SATURDAY. LOOKING AHEAD...DEVELOPING NORTHWEST FLOW LATE IN THE
PERIOD WILL LIKELY RESULT IN PERIODS OF SHORTWAVE ENERGY STREAMING
INTO THE STATE...BUT TIMING DIFFERENCES MAKE IT DIFFICULT TO FOCUS
ON ANY PARTICULAR PERIOD RIGHT NOW.
&&
.AVIATION...
MVFR/IFR STRATUS CONTINUES TO EXPAND ACROSS WESTERN AND CENTRAL NORTH
DAKOTA EARLY THIS MORNING...AND IS NOW IMPACTING ALL TAF SITES.
DENSE FOG HAS ALSO DEVELOPED AT KMOT AND WILL LIKELY PERSIST UNTIL
THE LOW CLOUD SHIELD MOVES IN. EXPECT A FEW FLURRIES THROUGH THE
MORNING AS WELL. MVFR CIGS SHOULD LINGER AT KJMS/KDIK THROUGH THE
AFTERNOON...WITH DECREASING CLOUDS AT KBIS/KISN/KMOT.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR NDZ002>005-
011>013-021>023.
&&
$$
SHORT TERM...AYD
LONG TERM/AVIATION...RK
AREA FORECAST DISCUSSION
NWS BISMARCK ND
104 AM CST WED MAR 6 2013
.DISCUSSION...
NO SIGNIFICANT CHANGES WERE REQUIRED WITH THIS FORECAST UPDATE AS
THE INHERITED FORECAST WAS WELL ON TRACK AND BLENDED TO THE 0630
UTC OBSERVED TRENDS.
SURFACE HIGH PRESSURE WAS IN PLACE ACROSS NORTH CENTRAL NORTH
DAKOTA AND INTO THE JAMES RIVER VALLEY. WITH FRESH SNOW AND CLEAR
SKIES...SUB-ZERO TEMPERATURES ARE BEING OBSERVED WITHIN THE
CENTER OF THE SURFACE HIGH. FOLLOWED CLOSELY TO THE LATEST RAP RUNS
FOR OVERNIGHT LOWS AS IT HAS A GOOD HANDLE ON THE TEMPERATURE
PATTERN THUS FAR THROUGH THE EARLY OVERNIGHT. THE BIGGEST
CHALLENGE FOR TONIGHT WILL BE THE EVOLUTION OF THE STRATUS ACROSS
WESTERN AND INTO SOUTH CENTRAL NORTH DAKOTA...WITH A BREAK IN THE
DECK UNTIL THE DEVILS LAKE BASIN AND EASTERN PORTIONS OF THE JAMES
RIVER VALLEY. AS HAS BEEN THE CASE...THE RAP ALSO HAS A GOOD
HANDLE ON THE STRATUS AND WILL FOLLOW ITS LOW LEVEL MOISTURE
FIELDS FOR CLOUD COVER THE REMAINDER OF THE NIGHT.
FINALLY...INCREASED THE WORDING FROM PATCHY FOG TO AREAS OF DENSE
FOG ACROSS THE NORTHWEST AND NORTH CENTRAL BASED UPON SURFACE
OBSERVATIONS AND WEBCAMS.
&&
.AVIATION...FOR THE 06Z WEDNESDAY TAF ISSUANCE...ONE STRATUS AREA
WITH MVFR CIGS STRETCHING FROM KISN TO KDIK...WHILE A SECOND AREA WAS
LOCATED OVER KJMS WITH FLURRIES AND OCCASIONAL REDUCTION TO MVFR
VSBYS. STRATUS WAS LOCATED JUST WEST OF KBIS...WITH SKC IN KMOT.
PATCHY FOG IS POSSIBLE AT KBIS/KMOT OVERNIGHT...WHILE STRATUS IS
FORECAST TO CONTINUE ELSEWHERE AND SLOWLY EXPAND THROUGH 12Z.
OVERALL...EXPECT MVFR CIGS AND PATCHY FOG TO PERSIST THROUGH MOST OF
WEDNESDAY MORNING. THE MVFR CIGS WILL SLOWLY IMPROVE TO LOW VFR
WEDNESDAY AFTERNOON.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AYD
AVIATION...KS
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
655 PM EST THU MAR 7 2013
.SYNOPSIS...
LOW PRESSURE OFF THE EAST COAST DRIFTS SLOWLY AWAY THROUGH
FRIDAY...ALLOWING HIGH PRESSURE TO BUILD IN THIS WEEKEND. A COLD
FRONT AND WAVE OF LOW PRESSURE MOVE THROUGH EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH FRIDAY NIGHT/...
STILL COULD SEE A PEAK OF SUN OR TWO INTO THE KANAWHA VALLEY THIS
AFTERNOON...BUT CANNOT ELIMINATING THE LOW LEVEL MOISTURE IN
PLACE DOWNWIND OF THE GREAT LAKES. RUC HAS THE STRATUS DECK THROUGH
05Z TONIGHT...AND OTHER MODELS DRYING OUT THE WESTERN LOWLANDS AFTER
06Z. THE SUN MAKES AN APPEARANCE FRIDAY WITH HIGH PRESSURE DRIFTING
ACROSS THE SOUTHERN GREAT LAKES AND DRYING LOW LEVELS. NAM AT 925MB
STILL HAS NORTHERLY FLOW AND SATURATION IN A LINGERING THERMAL
TROUGH...SO KEPT THE CLOUDS IN PLACE OVER THE TYGART AND GREENBRIER
VALLEYS. WILL SEE A SLOW IMPROVEMENT TO THE 850MB TEMPERATURES...BUT
WILL NOT QUITE GET INTO THE EFFICIENT WARM UP WITH A NORTHERLY
COMPONENT TO THE WIND AT THE SURFACE AN LOW LEVELS THROUGH 00Z
SATURDAY.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY/...
HIGH PRESSURE IS IN CONTROL AT THE SURFACE FOR THE FIRST HALF OF THE
WEEKEND...WITH A RIDGE BUILDING IN ALOFT. THIS WILL SPELL ABOVE
NORMAL AFTERNOON HIGHS ACROSS MUCH OF THE FORECAST AREA. HIGHS MAY
BE TEMPERED A BIT BY LINGERING SNOW COVER IN THE NORTHERN MOUNTAINS
OF WEST VIRGINIA SO STAY A BIT BELOW GUIDANCE THERE. MODEL TIMING A
LITTLE DIFFERENT ON WHEN THE LEADING PRECIP AHEAD OF THE NEXT SYSTEM
MAY ENTER OUR WESTERN ZONES. ONLY MADE LITTLE CHANGES FROM PREVIOUS
POP FORECAST...WITH SLIGHT CHANCE POPS ENTERING FROM THE WEST
SATURDAY AFTERNOON. DESPITE INCREASING HIGH CLOUDS...SUNDAY SHOULD
BE THE WARMER DAY OF THE WEEKEND...WITH LOW TO MID 60S PRETTY
WIDESPREAD ACROSS THE LOWER ELEVATIONS...AND UPPER 40S TO 50S IN THE
MOUNTAINS AS SNOW PACK CONTINUES TO MELT.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
MOISTURE FROM THE LEADING EDGE OF THE NEXT FRONTAL SYSTEM WILL BEGIN
TO SPREAD OVER THE WESTERN PORTIONS OF THE FORECAST AREA LATE SUNDAY
NIGHT AS THE WEEKENDS UPPER LEVEL RIDGE SLIDES EAST INTO THE
ATLANTIC. RAINFALL WILL BECOME MORE WIDESPREAD THROUGH THE DAY
MONDAY AS A FRONTAL SYSTEM WITH A GOOD SOUTHERLY FETCH SHIFTS EAST.
WITH TEMPERATURES REMAINING WARM DURING THIS TIME PERIOD WILL NEED
TO WATCH THE FRONT CLOSELY FOR HYDRO CONCERNS. SO FAR MODELS ARE
SHIFTING IT EAST QUICKLY ENOUGH TO KEEP PRECIPITATION AMOUNTS IN THE
INCH RANGE BUT IF WAVES END UP FORMING ALONG THE FRONTAL BOUNDARY
AND IT STALLS...THE NORTH TO SOUTH ORIENTATION OF THE SYSTEM WOULD
BE FAVORABLE FOR PICKING A GOOD BIT MORE RAIN. AGAIN AT MOMENT IT
DOES NOT LOOK LIKE THE FRONT WILL STALL BUT RATHER JUST SOMETHING TO
WATCH. COOLER AIR WILL SWING DOWN BEHIND THE FRONTAL MIDWEEK BUT
LOOKS FAR ENOUGH BEHIND THAT MOST OF THE LINGERING POST FRONTAL
SHOWERS WILL BE OVER WITH BY THEN.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
LOW LEVEL MOISTURE PERSISTENT AND CONTINUES TO CAUSE DIFFICULTIES
FIGURING OUT NOCTURNAL TRENDS OVERNIGHT. THERMAL TROF AT 925 TO 850
MB FINALLY BEGINS TO MODERATE AFTER 15Z...FORECASTING CLOUDS
BECOMING SCATTERED TO BROKEN BY 18Z.
WILL TRY TO LOWER CEILINGS 03Z TO 07Z WITH THE NOCTURNAL
COOLING...WITH WIDESPREAD CEILINGS 1 TO 2 THSD FT AFTER 06Z THROUGH
14Z. FLURRIES AND LIGHT SNOW SHOWERS MAY ACTUALLY INCREASE CKB TO
EKN AND CENTRAL WV MOUNTAINS BETWEEN 02Z THROUGH 06Z THEN DECREASE
AGAIN TOWARD 12Z. VSBY 3 TO 5 MILES IN THE SNOW SHOWERS.
HAVE CLOUDS THINNING 09Z TO 12Z...BREAKS IN CLOUDS MAY CAUSE SOME
AREAS OF MVFR IN HAZE AND LIGHT FOG THRU 14Z. CONSIDERING BOUNDARY
LAYER WINDS SHOULD CONTINUE TO BLOW FROM THE NORTH...WAS NOT
FORECASTING ANY THICK FOG.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z SATURDAY...
FORECAST CONFIDENCE...MEDIUM.
ALTERNATE SCENARIOS: WITH THE SATURATED LOW LEVELS...CEILING HEIGHTS
MAY VARY...EITHER HIGHER OR LOWER...FROM FORECAST...WITH 06Z TO 14Z
FRIDAY THE MOST VULNERABLE PERIOD.
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.
DATE FRI
UTC 1HRLY 00 01 02 03 04 05 06 07 08 09 10 11
EST 1HRLY 19 20 21 22 23 00 01 02 03 04 05 06
CRW CONSISTENCY H M M M M H L L L L L L
HTS CONSISTENCY H M M M M M M H L L L L
BKW CONSISTENCY H H M M L L L L L L L L
EKN CONSISTENCY L L L L L L L L L L L L
PKB CONSISTENCY H H H H H H H H M M M M
CKB CONSISTENCY L L H M M H H H H M L L
AFTER 00Z SATURDAY...
IFR POSSIBLE IN RAIN SHOWERS MONDAY INTO MONDAY NIGHT.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...MZ/26/JR
NEAR TERM...26
SHORT TERM...MZ
LONG TERM...JR
AVIATION...KTB
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
108 AM EST WED MAR 6 2013
.SYNOPSIS...
LOW PRESSURE PUSHES THROUGH OVERNIGHT...CHANGING RAIN TO SNOW. SNOW
ON ITS BACKSIDE WEDNESDAY. UPSLOPE SNOW UNDER NORTHWEST FLOW INTO
THE END OF THE WEEK NORTHEAST MOUNTAINS. HIGH PRESSURE BY WEEKEND.
&&
.NEAR TERM /UNTIL 9 AM THIS MORNING/...
UPDATED WIND DIRECTION...SPEED AND GUST AFTER EXTRAPOLATING SFC
LOW CENTER FROM THE RUC TO MATCH SFC OBS AND RADAR LOOP. REST OF
FORECAST REMAINS ON TRACK WITH PCPN CHANGING TO ALL SNOW BY
05Z.
PREVIOUS FORECAST BELOW...
930 PM UPDATE...
NEAR TERM TRENDS INCLUDING FASTER FALL ON TEMPERATURES WARRANT
STARTING THE ADVISORY FOR CENTRAL WV MOUNTAINS AND THE NORTHERN WV
LOWLANDS EARLIER. ALSO HAVE SLIGHTLY HIGHER SNOWFALL AMOUNTS FOR
THE NORTHERN MOUNTAINS OVERNIGHT GIVEN LOWER TEMPERATURES THERE.
ENHANCED WIND GUSTS TUG FORK / COAL FIELDS AREA AND EVEN INTO THE
HTS TRI-STATE AREA...ALL S OF THE LOW TRACK.
630 PM UPDATE...
COMPLEX FCST BY AND LARGE ON TRACK AS LOW PRESSURE ENTERS THE AREA
ALONG THE OHIO RIVER.
PREV DISCN...
PRECIPITATION SLOW IN PUSHING INTO THE CWA AFTER THE FIRST BATCH
DISSOLVED OUT SO...TRIMMED BACK SOME OF THE POPS OVER THE NORTHERN
ZONES OVER THE NEXT FEW HOURS UNTIL SHIELD ACCELERATES THROUGH. USED
THE LOCAL WRF MODELS TO ACCOUNT FOR THIS TIMING.
BIGGEST KEYS TO THE FORECAST TODAY ARE THE TIMING OF THE TEMPERATURE
DROPS TO AND BELOW FREEZING TONIGHT AND THE POTENTIAL OF LOW LEVEL
SUBSIDENCE OVER THE LOWLANDS NEAR 12Z WEDNESDAY. REGARDING THE
FORMER...MODELS WERE VERY SLUGGISH IN BRINGING THE TEMPERATURES DOWN
TO FREEZING FOR THE TRANSITION TO FROZEN PRECIPITATION. WEARY OF
THIS TEMPERATURE GUIDANCE UNDERDOING THE DYNAMIC COOLING ASPECT...SO
NUDGED THE HOURLIES DOWN A COUPLE DEGREES DURING THE TONIGHT TIME
PERIOD. THIS DOES NOT INCLUDE THE MOUNTAINS...AS THESE LOCATIONS
WERE COOL ENOUGH.
AS THE SNOWFALL BEGINS...WILL HAVE THAT LAG PERIOD WHERE RAIN AND
SLOWLY COOLING AIR WILL HINDER ACCUMULATIONS. COULD START AS SLUSHY
ACCUMULATIONS AT FIRST...ESPECIALLY FOR THE LOWLANDS. TRANSITION FOR
THE HIGHER ELEVATIONS AND SUBSEQUENT ACCUMULATIONS LOOKS TO BE MORE
EFFICIENT. BUT THERE WILL STILL BE A HEAVY AND WET NATURE TO THE
SNOW.
GFS AND NAM DEPICT SUBSIDENCE AT THE 700MB...AND VERY LITTLE LIFT AT
850MB OVER THE LOWLANDS...PARTICULARLY THE TRI STATE AREA.
THEREFORE...FEEL THE BULK OF THE SNOW...WHICH ARE GENERALLY AN INCH
OR LESS OVER THE CHARLESTON TO HUNTINGTON CORRIDOR...WILL FALL PRIOR
TO 12Z. POPS COME DOWN TO CHANCE AT THIS TIME. THIS IS NOT THE CASE
FOR THE NORTHERN TIER OF COUNTIES AND ALONG AND INCLUDING THE
MOUNTAINS...WHERE ACCUMULATIONS WILL CONTINUE WELL INTO THE SHORT
TERM.
NO ADJUSTMENTS TO THE HEADLINES AT THIS TIME.
&&
.SHORT TERM /9 AM THIS MORNING THROUGH THURSDAY NIGHT/...
PRECIPITATION SHOULD MAINLY BE IN THE FORM OF SNOW BY THE
START OF THE SHORT TERM PERIOD...AS UPPER LOW MOVES OFF TO THE SOUTH
AND EAST OF THE CWA. STILL EXPECTING SOME DECENT
ACCUMULATIONS...MAINLY IN THE 12Z TO 18Z TIME FRAME...AS MODELS
INDICATING GOOD DENDRITE GROWTH AND DYNAMICS CONTINUING DURING THIS
PERIOD. HOWEVER...AS THE DAY PROGRESSES...AND THE LOW PULLS FURTHER
AWAY...THIS WILL CHANGE AS MOISTURE DEPTH AND DYNAMICS DECREASE. MAY
EVEN SEE A TRANSITION TO DZ OR FZDZ LATER ON WEDNESDAY ACROSS SOME
OF THE LOWLANDS IN PARTICULAR AS LAYERS ABOVE 700MB GRADUALLY DRY
OUT. FOR NOW THOUGH...WILL JUST TRANSITION TO LIGHT SNOW SHOWERS
WITH LITTLE TO NO ACCUMULATIONS ACROSS LOWLANDS...WITH LIGHT
ADDITIONAL ACCUMULATIONS ACROSS MOUNTAIN ZONES IN THE NW UPSLOPE
FLOW.
IN ADDITION TO PRECIPITATION...STILL LOOKING AT DECENT WINDS
DEVELOP...PARTICULARLY ACROSS MOUNTAINOUS COUNTIES AS PRESSURE
GRADIENT TIGHTENS...AND STRONGER WINDS ALOFT DEVELOP. AS STATED IN
PREVIOUS FORECASTS...THIS WILL BE A RATHER HEAVY WET SNOW DURING THE
PERIOD.
AS THE LOW CONTINUES TO PULL OFF TO THE EAST ON WEDNESDAY...WILL SEE
A TRANSITION TO LIGHT UPSLOPE SNOW SHOWERS...WITH ADDITIONAL LIGHT
ACCUMULATIONS EXPECTED.
GUIDANCE SEEMS TO BE RUNNING A LITTLE HIGH DURING THE
PERIOD...PARTICULARLY ON WEDNESDAY MAX T...AND ELECTED TO KEEP
TEMPERATURES BELOW GUIDANCE ON THIS DAY AS LOW WILL CONTINUE TO PUSH
TO SOUTH AND EAST...BRINGING IN COLDER AIR...AND AS PLENTY OF CLOUD
COVER WILL LINGER DURING THE DAY WEDNESDAY. DESPITE REMAINING BELOW
GUIDANCE...DO HAVE MUCH OF THE LOWLAND COUNTIES INCHING ABOVE
FREEZING ON WEDNESDAY.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
MODELS SHOWING UPSLOPE SNOW SHOWERS ENDING IN THE MOUNTAINS ON
FRIDAY. HIGH PRESSURE THEN BUILDS IN FOR THE BEGINNING OF THE
WEEKEND. MODELS HAVE A LOT OF SPREAD WITH TIMING OF THE NEXT SYSTEM
EARLY NEXT WEEK. USED A ECMWF/GEFS ENSEMBLE MEAN BLEND...WHICH PUTS
THE TIMING BETWEEN THE GFS AND ECMWF.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
PCPN HAS CHANGED TO ALL SNOW ACROSS THE ENTIRE AREA BY 05Z.
PERIODS OF IFR UNDER BURSTS OF SNOW ARE LIKELY TO SPREAD FROM
SOUTH TO NORTH AS THE LOW PRESSURE MOVE ROUGHLY NORTHEAST ACROSS
PKB THROUGH 12Z. OTHERWISE...MVFR UNDER LIGHT SNOW WILL PREVAIL
THROUGH 09Z...DETERIORATING THROUGH 12Z. BIG CHALLENGE TO FORECAST
WIND DIRECTION AS WIND WILL CONTINUALLY BACK AS THE LOW MOVES
ACROSS. GUSTY WINDS ARE ALSO LIKELY IN THE PERIPHERY OF THE LOW
CENTER...BEING WEAKER ALONG THE CENTERS TRACK AND AT PROTECTED
MOUNTAIN VALLEYS SUCH AS EKN.
THE PRECIPITATION WILL BECOME LIGHTER AND MORE INTERMITTENT WED
MORNING...ALLOWING VSBYS TO IMPROVE TO MVFR AT LEAST AT TIMES WED
MORNING. CIGS AND VSBYS MAY IMPROVE TO VFR ALONG AND W OF THE OHIO
RIVER BY LATE WED AFTERNOON...WHILE MVFR VSBYS AND CIGS REMAIN IN
THE MOUNTAINS IN SNOW SHOWERS.
SOUTH OF THE LOW...GUSTY SOUTHEAST FLOW WILL BECOME SOUTHWEST OVERNIGHT
AND THEN GUSTY NORTHWEST WED MORNING. GUSTY NORTHWEST FLOW THROUGHOUT
THE AREA WED AFTERNOON.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z THURSDAY...
FORECAST CONFIDENCE...MEDIUM.
ALTERNATE SCENARIOS: WIND DIRECTIONS AND SPEEDS WILL BE HIGHLY
VARIABLE...AND COULD BE INCONSISTENT FROM HOUR TO HOUR. CEILINGS
COULD BOUNCE FROM MVFR TO IFR AS WIND SPEEDS AND INTENSITY OF SNOW CHANGE.
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.
DATE WED 03/06/13
UTC 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17
EST 1HRLY 01 02 03 04 05 06 07 08 09 10 11 12
CRW CONSISTENCY L L L L L L L L L L H H
HTS CONSISTENCY M M M M M M M L H H H H
BKW CONSISTENCY L L L L M M M M M M L L
EKN CONSISTENCY M M M M M M M M M M M M
PKB CONSISTENCY L L M M M M M L L H H H
CKB CONSISTENCY M M M M M M M M M M M M
AFTER 06Z THURSDAY...
IFR VISIBILITIES AND CEILINGS POSSIBLE IN SNOW SHOWERS WED NT INTO
THU...ESPECIALLY IN THE WV MOUNTAINS.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
WVZ009>011-019.
WINTER WEATHER ADVISORY UNTIL 1 AM EST THURSDAY FOR WVZ020-028-
030>032-035>037-039-040.
WINTER STORM WARNING UNTIL 1 AM EST THURSDAY FOR WVZ038-046-
047.
OH...WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
OHZ066-067-075-076.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...TRM/RPY/SL/26
NEAR TERM...ARJ/TRM/26
SHORT TERM...SL
LONG TERM...RPY
AVIATION...ARJ
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
1220 AM EST WED MAR 6 2013
.SYNOPSIS...
A WINTER STORM WILL AFFECT THE AREA TONIGHT AND EARLY WEDNESDAY.
HIGH PRESSURE WILL BUILD ACROSS THE REGION LATE THIS WEEK...LASTING
INTO THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
MADE SOME MINOR TWEAKS TO STORM TOTAL SNOW AND MADE ADJUSTMENTS TO
THE WEATHER GRIDS DURING THIS EVENING UPDATE. ALSO INCREASED WINDS
ACROSS THE SOUTH AND WEST AS SURFACE PRESSURE GRADIENT HAS
INCREASED ACROSS THE SOUTH...AND WILL LATER TONIGHT ACROSS THE
WEST. THIS WILL PRODUCE GUSTS OVER 30 MPH AT TIMES DURING THE
OVERNIGHT PERIOD FOR THOSE ZONES. RAIN/SNOW LINE HAS PROGRESSED TO
JUST WEST OF THE COLUMBUS AREA. PRECIPITATION WILL CONTINUE TO
TRANSITION TO SNOW ACROSS THE FAR EASTERN ZONES TOWARD
MIDNIGHT...WITH ALL SNOW FOR THOSE ZONES BY MIDNIGHT. HAVE HAD
REPORTS OF ISOLATED THUNDER ASSOCIATED WITH A STRONGER SNOW BAND
EXTENDING FROM DARKE COUNTY...SOUTHEASTWARD ACROSS WARREN COUNTY.
THESE THUNDER OCCURRENCES ARE ISOLATED IN NATURE.
THEREFORE...WILL HOLD OFF ON ADDING THE MENTION OF IT IN THE GRIDS
ATTM. THE PEAK SNOW INTENSITY WILL BE FROM NOW UNTIL A COUPLE OF
HOURS AFTER MIDNIGHT...AS THE BEST LIFT PRODUCES THE HIGHEST RATES
OF ACCUMULATION IN OUR AREA.
.PREVIOUS DISCUSSION AT 423 PM EST...
AN UPPER LOW IS DIVING SOUTHEASTWARD OUT OF THE NORTHERN PLAINS
AND INTO THE TENNESSEE VALLEY THIS EVENING. A SURFACE LOW
DEVELOPING OVER KENTUCKY...OUT AHEAD OF THE UPPER LOW WILL DEEPEN
AND PIVOT NORTHEASTWARD OVER THE OHIO VALLEY AS THE UPPER LOW
SLIDES BY TO THE SOUTH TONIGHT. PRECIPITATION IS ALREADY SPREADING
NORTHWARD ACROSS THE FORECAST AREA AHEAD OF THE INTENSIFYING
SURFACE LOW. PRECIPITATION WILL FALL AS RAIN ACROSS THE AREA INTO
THE EARLY EVENING...AS WARM AIR IS DRAWN NORTH AND WEST INTO THE
LOW LEVELS AROUND THE LOW.
THE FORECAST FOR LATER THIS EVENING BECOMES COMPLICATED...AS COLD
AIR BEGINS TO WORK ITS WAY BACK INTO THE LOW. THIS PROCESS WILL BE
TWOFOLD. LOW LEVEL COLD ADVECTION WILL ALLOW FOR COLDER AIR TO
WRAP INTO THE SURFACE LOW. AT THE SAME TIME...ABUNDANT VERTICAL
MOTION WILL PROVIDE FOR DYNAMIC COOLING FROM THE MIDDLE
LEVELS...PROPAGATING TO THE SURFACE. MODELS ARE IN AGREEMENT ON
THE STRONG VERTICAL MOTION ASSOCIATED WITH THIS SYSTEM THIS
EVENING ACROSS OUR AREA. HOWEVER...THERE ARE CRITICAL DIFFERENCES
IN HOW THE MODELS ARE HANDLING THE BATTLE BETWEEN DYNAMIC
COOLING...AND WARM AIR BEING PULLED IN AROUND THE LOW. BASED ON
HOW STRONG ASCENT IS AS HEAVIER PRECIPITATION MOVES IN THIS
EVENING...THIS FORECAST PACKAGE WENT WITH A MODERATELY FAST
CHANGEOVER TO SNOW TO BEGIN IN THE WESTERN ZONES AROUND 7
PM...SPREADING EAST THROUGH THE DAYTON/CINCY AREAS BY 9 PM...THEN
COLUMBUS BY 10 OR 11 PM. IF THE DYNAMIC COOLING PROCESS IS
STRONGER THAN THIS FORECAST IS HINTING AT...THEN THIS CHANGEOVER
WILL OCCUR SOONER...WITH THE RESULT BEING HIGHER SNOW TOTALS. OF
COURSE...IF ADDITIONAL WARMER AIR IS DRAW INTO THE SYSTEM...LIKE
THE RAP SUGGESTS THEN MORE RAIN WILL FALL INITIALLY. THE RAP
SOLUTION HAS BEEN ON THE WARM SIDE TODAY...THEREFORE AM LEANING
TOWARD THE COLDER SOLUTIONS.
ANY SNOW THAT OCCURS JUST AFTER THE CHANGEOVER WILL BE A
HEAVY...WET SNOW. THE BOTTOM LINE IS THAT THE MODELS LOOK AS IF
THEY ARE PICKING UP ON THE STRONGER LIFT BASED ON QPF AMOUNTS
RISING OVER RECENT RUNS. THIS MEANS A POTENTIAL FOR HIGHER STORM
TOTALS FOR OUR AREA. TOTAL SNOWFALL NUMBERS WERE THEREFORE TWEAKED
SLIGHTLY HIGHER...WITH THE MAXIMUM BEING AROUND 8 INCHES STORM
TOTAL ACROSS THE NORTHWESTERN ZONES. SOME OF THE SOUTHWESTERN
ZONES...WHERE A TRANSITION WILL OCCUR FIRST...MAY RECEIVE UP TO 4
INCHES OF SNOW. THE TRICKIEST SNOWFALL TOTAL FORECAST LIED WHERE
THE CENTER OF THE SURFACE LOW IS EXPECTED TO SPIN FOR A FEW HOURS
TONIGHT...ACROSS THE SCIOTO VALLEY. THERE...SNOWFALL AMOUNTS COULD
VARY QUITE A BIT...NOT ONLY DUE TO THE DELAYED CHANGEOVER DUE TO
SOME WARMER AIR...BUT THE LACK OF HEAVIER QPF UNDERNEATH THE LOW`S
CENTER LATE TONIGHT.
EXPANDED THE WINTER STORM WARNING TO INCLUDE SOME OUR OUR NORTHERN
KENTUCKY ZONES THAT ARE NOW EXPECTED TO REACH OUR 12 HOUR
CRITERIA OF 4 INCHES OF SNOW TONIGHT. DID DELAY THE START OF ALL
WARNINGS/ADVISORY EXCEPT ACROSS THE EXTREME NORTH...SINCE THAT
WARNING WAS ALREADY IN EFFECT AT THE TIME OF THE FORECAST PACKAGE
ISSUANCE.
SNOW WILL CONTINUE THROUGHOUT THE EARLY PRE-DAWN HOURS AS THE SURFACE
LOW SPINS ACROSS SOUTHEASTERN OHIO.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH THURSDAY NIGHT/...
THE UPPER LOW WILL QUICKLY SHIFT TOWARD THE MID ATLANTIC STATES
WEDNESDAY MORNING AS A SECONDARY SURFACE LOW DEVELOPS CLOSER TO
THE EASTERN SEABOARD. THIS ENERGY TRANSFER EASTWARD...AND AWAY
FROM OUR AREA WILL BRING A RAPID END TO FORCING SUPPORTING STEADY
SNOW IN OUR AREA. SNOW WILL TAPER OFF QUICKLY AROUND SUNRISE WITH
ONLY SOME LIGHTER SNOW SHOWERS EXPECTED DURING THE DAY.
NORTHERLY FLOW BEHIND THE DEPARTING STORM SYSTEM AND RIDGING
ACROSS THE NORTHERN PLAINS WILL KEEP A CHANCE FOR LIGHT SNOW OR
FLURRIES IN OUR AREA THROUGH WEDNESDAY NIGHT AND INTO THE DAY
THURSDAY. TEMPERATURES DURING THIS TIME PERIOD WILL REMAIN BELOW
NORMAL. LOW LEVEL MOISTURE...AND ASSOCIATED CLOUD COVER WILL
FINALLY BEGIN TO GIVE WAY TO DRIER CONDITIONS THURSDAY NIGHT...AS
THE RIDGE BUILDS ACROSS THE OHIO VALLEY. TEMPERATURES WILL LIKELY
BOTTOM OUT THURSDAY NIGHT IN THE UPPER TEENS TO LOW 20S UNDER
PARTLY CLOUDY SKIES.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AFTER A PLEASANT AND GENERALLY MILD WEEKEND...WITH GOOD MODEL
AGREEMENT...THERE IS CONSIDERABLE UNCERTAINTY ON A WEATHER SYSTEM
MOVING INTO THE REGION EARLY NEXT WEEK.
THE WEEKEND WILL BEGIN WITH A MID LEVEL TROUGH AXIS EXTENDING FROM
THE GULF OF MEXICO TO NORTHERN INDIANA. WARM ADVECTION WILL BE
UNDERWAY ALOFT...AND SHOULD BEGIN AT THE SURFACE AS WELL (AS WINDS
TAKE A SOUTHERLY COMPONENT). THIS PATTERN WILL GENERALLY CONTINUE
INTO SUNDAY...AS THE RIDGE AXIS MOVES EAST. WITH QUITE A BIT OF SUN
ON SATURDAY (PERHAPS JUST SOME LOW CLOUDS THAT ARE SLOW TO MOVE OUT
OF THE NORTHEASTERN CWA)...TEMPERATURES WILL RISE ABOVE NORMAL BY
ABOUT 5 DEGREES.
THE RIDGE WILL CONTINUE TO DOMINATE THE WEATHER ON SUNDAY...BUT AS
INFLUENCE FROM THE DEVELOPING WEATHER SYSTEM IN THE WESTERN STATES
BEGINS TO COMPLICATE THE FORECAST...SOME UNCERTAINTY WILL BEGIN TO
SET IN. MOISTURE WILL BEGIN TO ADVECT IN ALOFT...LEADING TO HIGH
CLOUDS THICKENING THROUGH THE DAY. DESPITE THIS...SURFACE WARM
ADVECTION WILL BE STRENGTHENING...LEADING TO EVEN WARMER TEMPS ON
SUNDAY.
BEYOND SUNDAY...A VERY HIGH AMOUNT OF UNCERTAINTY EXISTS IN THE
FORECAST. IT APPEARS CERTAIN THAT A WESTERN TROUGH WILL EJECT INTO
THE EASTERN STATES...AS SURFACE LOW PRESSURE DEVELOPS AND MOVES
THROUGH OR NEAR THE OHIO VALLEY. HOWEVER...THERE IS VERY LOW
CONFIDENCE IN THE TIMING OF THIS SYSTEM...AS WELL AS IN THE
PLACEMENT OF THE SURFACE LOW. DETERMINISTIC MODELS (12Z GFS VS 12Z
CMC VS 00Z ECMWF) ARE AS MUCH AS A DAY AND A HALF OFF IN
TIMING...WITH THE SURFACE LOW POSSIBLY GOING NORTH OR SOUTH OF THE
AREA. SO...AT THIS TIME...THE FORECAST WILL REMAIN VERY GENERAL.
ALTHOUGH IT IS FRUSTRATING TO GO NO HIGHER THAN 30 POPS WHEN RAIN
APPEARS A VIRTUAL CERTAINTY AT SOME POINT IN THE SUNDAY NIGHT
THROUGH TUESDAY TIME FRAME...THE TIMING DIFFERENCES ARE TOO GREAT TO
GO HIGHER.
&&
.AVIATION /05Z WEDNESDAY THROUGH SUNDAY/...
A DYNAMIC STORM SYSTEM WILL CONTINUE TO AFFECT THE REGION THROUGH
12Z WITH SNOW AND WIND. SURFACE LOW PRESSURE OVER SOUTHEAST OHIO
THIS MORNING WILL BEGIN TO WEAKEN OVER SOUTHEAST OHIO BETWEEN 09Z
AND 12Z AS PARENT UPPER LEVEL LOW PUSHES EAST TOWARD THE MID
ATLANTIC...ALLOWING A STRONGER SURFACE LOW DEVELOP NEAR THE COAST.
THIS IS THE TYPICAL ENERGY TRANSFER WE SEE IN THE OHIO VALLEY.
SNOW...MODERATE TO LOCALLY HEAVY AT TIMES...SHOULD QUICKLY TAPER
OFF FROM NW TO SOUTHEAST BY SUNRISE. CONDITIONS WILL REMAIN CLOSE
TO AIRFIELD MINIMUMS UNTIL THE SNOW TAPERS OFF. THEREAFTER...SKIES
WILL REMAIN MOSTLY CLOUDY TO CLOUDY WITH VSBYS IMPROVING TO VFR
AND CEILINGS REMAINING IN THE MVFR RANGE BETWEEN 1500 AND 2000
FEET. GUSTY NORTH WINDS WILL BEGIN TO TAPER OFF TOWARD 00Z
THURSDAY.
OUTLOOK...MVFR CEILINGS TO LINGER INTO THURSDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...WINTER STORM WARNING UNTIL 1 PM EST THIS AFTERNOON FOR OHZ026-
034-035-042>046-051>056-060>065-070>072-077>080.
WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
OHZ073-074-081-082-088.
KY...WINTER STORM WARNING UNTIL 1 PM EST THIS AFTERNOON FOR
KYZ089>093.
WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
KYZ094>100.
IN...WINTER STORM WARNING UNTIL 1 PM EST THIS AFTERNOON FOR INZ050-
058-059-066-073>075-080.
&&
$$
SYNOPSIS...LATTO
NEAR TERM...LATTO
SHORT TERM...LATTO
LONG TERM...HATZOS
AVIATION...HICKMAN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
436 AM EST WED MAR 6 2013
.SYNOPSIS...
LOW PRESSURE OVER SOUTHERN OHIO WILL WEAKEN AS A SECONDARY LOW
DEVELOPS OVER THE SOUTHERN MID-ATLANTIC PIEDMONT EARLY THIS
MORNING. THE LOW WILL TRACK SLOWLY NORTHEAST TO THE VIRGINIA
TIDEWATER REGION THIS AFTERNOON AND MOVE OFF THE DELMARVA
PENINSULA BY THIS EVENING. THIS COMPLEX STORM SYSTEM WILL BRING
MODERATE TO HEAVY SNOW TO SOUTH-CENTRAL PENNSYLVANIA. HIGH
PRESSURE WILL BUILD IN FROM THE WEST FOR THE WEEKEND WITH FAIR
WEATHER AND TEMPERATURES RISING TO NEAR NORMAL.
&&
.NEAR TERM /UNTIL 7 AM THIS MORNING/...
RADAR AND SATL LOOP SHOW WELL-DEFINED COMMA HEAD/DEFORMATION PCPN
BAND SPREADING NWD INTO SRN PA AS UPPER LOW AND ASSOCD HT FALLS
APPROACH THE SPINE OF THE N-CENTRAL APPALACHIANS. 06Z RUC SFC
ANALYSIS SHOWS PRIMARY/OCCLUDED LOW OVER SRN OH WITH SECONDARY LOW
DEVELOPING OVER THE NC/VA PIEDMONT IN RESPONSE TO 2-4MB 3HR PRES
FALLS. AS THE SECONDARY LOW BEGINS TO TRACK SLOWLY TO THE NE
EARLY THIS MORNING...EXPECT INCREASING FGEN FORCING TO SUPPORT
OCNL 1-1.5 IN/HR SNFL RATES OVR FAR SWRN/S-CENTRAL PA AS THE SNOW
BAND CONTINUES TO PUSH NORTH ACRS THE MASON DIXON LINE. ALTHOUGH
TEMPS ARE STILL A FEW DEGS ABOVE 32F IN SOME AREAS...EXPECT WET
BULB/NOCTURNAL EFFECTS AND ISALLOBARIC FORCING/COLDER NLY FLOW TO
RESULT IN ALL SNOW PTYPES. EXTRAPOLATION OF RADAR TRENDS ALONG
WITH CONSENSUS OF HI-RES MDLS SHOWS THE NRN EDGE OF THE SNOW CONFINED
ALONG AND SOUTH OF IDI-LNS LINE THRU AT LEAST THE NEXT FEW
HOURS/09Z WITH A SLIGHT NWD SHIFT LKLY BY 12Z. A VERY SHARP
GRADIENT WILL MAKE FOR A DIFFICULT SPATIAL FCST WITH SNOW/NO SNOW
OBS OVER A VERY SHORT N-S DISTANCE. EXPECT SEVERAL INCHES OF ACCUM
/2-4" IN 6 HRS/ BY DAYBREAK FROM SOMERSET COUNTY EWD TOWARD SOUTH
MTN.
&&
.SHORT TERM /7 AM THIS MORNING THROUGH 6 PM THURSDAY/...
GUIDANCE CURRENTLY TRENDING A LITTLE FARTHER TO THE SOUTH AND
FURTHER DECREASES PRECIP AMOUNTS OVER THE AREA. BUT THIS COULD
JUST BE THE LATEST WAGGLE. HOWEVER...WE ARE FULLY INTO THE REALM
OF THE SHORT RANGE MODELS AT THIS MOMENT. SO...CONFIDENCE IS HIGH
ON THE AMOUNTS FROM A BLEND OF THE NAM/GFS/SREF. HEAVY SNOW MOST
LIKELY IN THE LAURELS AND ALONG THE MD BORDER WHERE THE HIGHEST
INFLUX OF MSTR FROM THE EAST IS POINTED. THE TREMENDOUS EASTERLY
FLOW WILL CREATE A HIGHLY ANOMALOUS 8H POSITIVE MOISTURE FLUX AREA
OVER THE SRN COUNTIES DURING THE MORNING AND EARLY AFTN IN OUR
SRN COS. THE EXPECTED MESOSCALE HEAVY BANDS OF SNOW WILL BE
CAPABLE OF MAKING INCH OR MORE PER HOUR RATES. SO EVEN A SHORTER
TIME IN THE FAVORED SNOWFALL PERIOD - NOW MORE LIKE 12-18HRS
RATHER THAN A FULL 24 HRS - KEEPS US JUST AS LIKELY TO GET 6 INCHES
OR MORE OF ACCUM ACROSS THE SOUTH.
THE STORM CENTER WILL BE ALMOST FULLY TRANSITIONED TO THE
SECONDARY CENTER AT THE BEGINNING OF THE PERIOD. THE TRACK MADE BY
THE STRONG CONSENSUS OF THE DETERMINISTIC MDLS AND ENSEMBLE
MEMBERS TAKES IT OUT TO SEA FAR ENOUGH BY WED NIGHT TO DECREASE
THE POPS IN THE WEST WED AFTN...AND IN THE EAST AROUND MIDNIGHT.
HOWEVER...A POSSIBLE NORTHWARD CURVE TO THE STORM WEDNESDAY
EVENING WHEN IT IS WELL OF THE COAST COULD DELAY THE EXIT OF VERY
LIGHT PRECIP FROM THE EASTERN COUNTIES UNTIL LATE WED NIGHT.
TEMPS ARE AN INTERESTING PART OF THIS FCST - WITH WIDESPREAD
30-33F TEMPS AS THE PRECIP OCCURS. THIS WILL LIKELY CREATE A
SOMEWHAT ELEV-DEPENDENT SNOW FALL. LANCASTER CO AND THE LOWER
ELEVS OF YORK/DAUPHIN/LEBANON CO WILL BE MOST AT-RISK TO SEE A
LITTLE RAIN MIX IN LATE WED/EARLY WED NIGHT. WILL DRAW SNOW ACCUM
MAP MORE BROAD- BRUSHED THOUGH FOR SIMPLICITY/S SAKE. THIS ALSO
KEEPS A VERY STRONG CONTINUITY IN THE FORECAST SNOW AMOUNTS.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
LARGE STORM SYSTEM SLIDES OFF EAST COAST BY THURSDAY...WHILE A
CHILLY AND RATHER GUSTY NORTHERLY FLOW ARRIVES WITH ISOLATED TO
SCATTERED MTN SNOW SHOWERS. AFTER THAT...HEIGHTS BEGIN TO RISE
ON FRI...WITH DAYTIME TEMPS MODERATING TO SEASONAL NORMALS
THROUGH THE WEEKEND.
WARMING TREND CONTINUES INTO EARLY NEXT WEEK...BUT WITH
SIGNIFICANT MODEL DIVERGENCE DEVELOPING IN LONGER TERM MODELS.
BUT GENERAL PATTERN KEEPS BROAD MILDER WESTERLY FLOW TO EASTERN
U.S. WITH A WEAKENING LOW LIFTING ACROSS THE NORTHEAST MON NIGHT
INTO TUE INCREASING CHANCES FOR PRIMARILY RAIN SHOWERS.
&&
.AVIATION /09Z WEDNESDAY THROUGH SUNDAY/...
SNOW SHOWERS ARE CURRENTLY STREAMING FROM THE SOUTH ENVELOPING PA
THIS MORNING. LIFR CONDITIONS AT JST AND AOO WILL CONTINUE THROUGH
THE FIRST HALF OF THE DAY...BEFORE SUBSIDING BY 18Z. EXPECT MVFR
TO IFR CIGS TO CONTINUE THROUGH MOST OF THE DAY. THE LOW LEVEL
MOISTURE COULD ALLOW FOR IFR AND LOWER CIGS TONIGHT.
ELSEWHERE THE SNOW IS CURRENTLY BRINGING MVFR CIGS AND VSBYS TO
MDT...AND MVFR CIGS OUT AHEAD OF THE SYSTEM AT UNV. IFR CONDITIONS
ARE EXPECTED AS THE SNOW INTENSIFIES THROUGH THIS MORNING AT
MDT...LNS. DUE TO THE MOVEMENT OF THE LOW...THESE SITES WILL
REMAIN BELOW VFR FOR THE LONGEST PERIOD DUE TO THIS STORM. EXPECT
IFR CIGS AND VSBYS POSSIBLE THROUGH 00Z. IPT AND UNV WILL HAVE
MVFR VSYBS TO IFR CIGS POSSIBLE THROUGH THE FIRST HALF OF THE DAY
BEFORE IMPROVING INTO THE EARLY EVENING. BFD WILL BE VFR THROUGH
MOST OF THE PERIOD...WITH ONLY SOME MVFR CIGS POSSIBLE OVERNIGHT
TONIGHT...AS THE FLOW SHIFTS TO THE NORTH. LOW LEVEL WIND- SHEAR
WILL ALSO BE POSSIBLE AS LOW LEVEL NORTHEAST FLOW QUICKLY CHANGES
AND INCREASES TO EASTERLY JUST OFF THE SURFACE.
EXPECT IMPROVING CONDITIONS FOR THU INTO SAT...AS HIGH PRESSURE
BUILDS EASTWARD.
OUTLOOK...
THU...MVFR/IFR -SHSN EARLY...BECOMING VFR.
FRI-SUN...NO SIG WX.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 2 AM EST THURSDAY FOR PAZ057>059.
WINTER STORM WARNING UNTIL 10 PM EST THIS EVENING FOR
PAZ024>026-033>036-063-064.
WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR
PAZ027-028-056.
WINTER STORM WARNING UNTIL 2 AM EST THURSDAY FOR PAZ065-066.
&&
$$
SYNOPSIS...STEINBUGL
NEAR TERM...STEINBUGL
SHORT TERM...DANGELO
LONG TERM...RXR/TYBURSKI
AVIATION...LA CORTE/CERU
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
128 AM EST WED MAR 6 2013
.SYNOPSIS...
LOW PRESSURE OVER SOUTHERN OHIO WILL WEAKEN AS A SECONDARY LOW
DEVELOPS OVER THE SOUTHERN MID-ATLANTIC PIEDMONT EARLY THIS
MORNING. THE LOW WILL TRACK SLOWLY NORTHEAST TO THE VIRGINIA
TIDEWATER REGION THIS AFTERNOON AND MOVE OFF THE DELMARVA
PENINSULA BY THIS EVENING. THIS COMPLEX STORM SYSTEM WILL BRING
MODERATE TO HEAVY SNOW TO SOUTH-CENTRAL PENNSYLVANIA. HIGH
PRESSURE WILL BUILD IN FROM THE WEST FOR THE WEEKEND WITH FAIR
WEATHER AND TEMPERATURES RISING TO NEAR NORMAL.
&&
.NEAR TERM /UNTIL 7 AM THIS MORNING/...
RADAR AND SATL LOOP SHOW WELL-DEFINED COMMA HEAD/DEFORMATION PCPN
BAND SPREADING NWD INTO SRN PA AS UPPER LOW AND ASSOCD HT FALLS
APPROACH THE SPINE OF THE N-CENTRAL APPALACHIANS. 06Z RUC SFC
ANALYSIS SHOWS PRIMARY/OCCLUDED LOW OVER SRN OH WITH SECONDARY LOW
DEVELOPING OVER THE NC/VA PIEDMONT IN RESPONSE TO 2-4MB 3HR PRES
FALLS. AS THE SECONDARY LOW BEGINS TO TRACK SLOWLY TO THE NE
EARLY THIS MORNING...EXPECT INCREASING FGEN FORCING TO SUPPORT
OCNL 1-1.5 IN/HR SNFL RATES OVR FAR SWRN/S-CENTRAL PA AS THE SNOW
BAND CONTINUES TO PUSH NORTH ACRS THE MASON DIXON LINE. ALTHOUGH
TEMPS ARE STILL A FEW DEGS ABOVE 32F IN SOME AREAS...EXPECT WET
BULB/NOCTURNAL EFFECTS AND ISALLOBARIC FORCING/COLDER NLY FLOW TO
RESULT IN ALL SNOW PTYPES. EXTRAPOLATION OF RADAR TRENDS ALONG
WITH CONSENSUS OF HI-RES MDLS SHOWS THE NRN EDGE OF THE SNOW CONFINED
ALONG AND SOUTH OF IDI-LNS LINE THRU AT LEAST THE NEXT FEW
HOURS/09Z WITH A SLIGHT NWD SHIFT LKLY BY 12Z. A VERY SHARP
GRADIENT WILL MAKE FOR A DIFFICULT SPATIAL FCST WITH SNOW/NO SNOW
OBS OVER A VERY SHORT N-S DISTANCE. EXPECT SEVERAL INCHES OF ACCUM
/2-4" IN 6 HRS/ BY DAYBREAK FROM SOMERSET COUNTY EWD TOWARD SOUTH
MTN.
&&
.SHORT TERM /7 AM THIS MORNING THROUGH 6 PM THURSDAY/...
GUIDANCE CURRENTLY TRENDING A LITTLE FARTHER TO THE SOUTH AND
FURTHER DECREASES PRECIP AMOUNTS OVER THE AREA. BUT THIS COULD
JUST BE THE LATEST WAGGLE. HOWEVER...WE ARE FULLY INTO THE REALM
OF THE SHORT RANGE MODELS AT THIS MOMENT. SO...CONFIDENCE IS HIGH
ON THE AMOUNTS FROM A BLEND OF THE NAM/GFS/SREF. HEAVY SNOW MOST
LIKELY IN THE LAURELS AND ALONG THE MD BORDER WHERE THE HIGHEST
INFLUX OF MSTR FROM THE EAST IS POINTED. THE TREMENDOUS EASTERLY
FLOW WILL CREATE A HIGHLY ANOMALOUS 8H POSITIVE MOISTURE FLUX AREA
OVER THE SRN COUNTIES DURING THE MORNING AND EARLY AFTN IN OUR
SRN COS. THE EXPECTED MESOSCALE HEAVY BANDS OF SNOW WILL BE
CAPABLE OF MAKING INCH OR MORE PER HOUR RATES. SO EVEN A SHORTER
TIME IN THE FAVORED SNOWFALL PERIOD - NOW MORE LIKE 12-18HRS
RATHER THAN A FULL 24 HRS - KEEPS US JUST AS LIKELY TO GET 6 INCHES
OR MORE OF ACCUM ACROSS THE SOUTH.
THE STORM CENTER WILL BE ALMOST FULLY TRANSITIONED TO THE
SECONDARY CENTER AT THE BEGINNING OF THE PERIOD. THE TRACK MADE BY
THE STRONG CONSENSUS OF THE DETERMINISTIC MDLS AND ENSEMBLE
MEMBERS TAKES IT OUT TO SEA FAR ENOUGH BY WED NIGHT TO DECREASE
THE POPS IN THE WEST WED AFTN...AND IN THE EAST AROUND MIDNIGHT.
HOWEVER...A POSSIBLE NORTHWARD CURVE TO THE STORM WEDNESDAY
EVENING WHEN IT IS WELL OF THE COAST COULD DELAY THE EXIT OF VERY
LIGHT PRECIP FROM THE EASTERN COUNTIES UNTIL LATE WED NIGHT.
TEMPS ARE AN INTERESTING PART OF THIS FCST - WITH WIDESPREAD
30-33F TEMPS AS THE PRECIP OCCURS. THIS WILL LIKELY CREATE A
SOMEWHAT ELEV-DEPENDENT SNOW FALL. LANCASTER CO AND THE LOWER
ELEVS OF YORK/DAUPHIN/LEBANON CO WILL BE MOST AT-RISK TO SEE A
LITTLE RAIN MIX IN LATE WED/EARLY WED NIGHT. WILL DRAW SNOW ACCUM
MAP MORE BROAD- BRUSHED THOUGH FOR SIMPLICITY/S SAKE. THIS ALSO
KEEPS A VERY STRONG CONTINUITY IN THE FORECAST SNOW AMOUNTS.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
LARGE STORM SYSTEM SLIDES OFF EAST COAST BY THURSDAY...WHILE A
CHILLY AND RATHER GUSTY NORTHERLY FLOW ARRIVES WITH ISOLATED TO
SCATTERED MTN SNOW SHOWERS. AFTER THAT...HEIGHTS BEGIN TO RISE
ON FRI...WITH DAYTIME TEMPS MODERATING TO SEASONAL NORMALS
THROUGH THE WEEKEND.
WARMING TREND CONTINUES INTO EARLY NEXT WEEK...BUT WITH
SIGNIFICANT MODEL DIVERGENCE DEVELOPING IN LONGER TERM MODELS.
BUT GENERAL PATTERN KEEPS BROAD MILDER WESTERLY FLOW TO EASTERN
U.S. WITH A WEAKENING LOW LIFTING ACROSS THE NORTHEAST MON NIGHT
INTO TUE INCREASING CHANCES FOR PRIMARILY RAIN SHOWERS.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
UPCOMING STORM STILL ON TRACK TO HAVE THE HIGHEST IMPACT ALONG
THE SOUTHERN TIER OF THE FCST AREA...WITH IMPACTS DECREASING OVER
CENTRAL AND NORTHERN PA.
SNOW IS INVADING SWRN AREAS AS OF 11 PM...AND WILL SPREAD
EASTWARD FOR THE REMAINDER OF THE OVERNIGHT. AS THE LOW MOVES OFF
TO OUR SOUTH AND INTENSIFIES LATE TONIGHT AND EARLY
WEDNESDAY...SNOW WILL INCREASE IN INTENSITY WITH RAPID
DETERIORATION TO IFR/LIFR VISIBILITIES TO BE EXPECTED. BEST CHANCE
OF IFR/LIFR WILL BE FROM JST EAST TO MDT/LNS. LOW LEVEL WIND-SHEAR
WILL ALSO BE POSSIBLE AS LOW LEVEL NORTHEAST FLOW QUICKLY CHANGES
AND INCREASES TO EASTERLY JUST OFF THE SURFACE.
ACROSS CENTRAL AND NORTHERN PENNSYLVANIA...SNOWFALL AND FLIGHT
CONDITIONS WILL BE LESS AFFECTED. MVFR TO OCCASIONAL IFR AT KUNV
POSSIBLY UP TO KIPT. KBFD WILL BE THE LEAST AFFECTED WITH VFR TO
OCCASIONAL MVFR AT TIMES IN MAINLY FLURRIES.
EXPECT IMPROVING CONDITIONS FOR THU INTO SAT...AS HIGH PRESSURE
BUILDS EASTWARD.
OUTLOOK...
THU...MVFR/IFR -SHSN EARLY...BECOMING VFR.
FRI-SUN...NO SIG WX.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 2 AM EST THURSDAY FOR PAZ027-028-
056>059.
WINTER STORM WARNING UNTIL 10 PM EST THIS EVENING FOR
PAZ024>026-033>036-063-064.
WINTER STORM WARNING UNTIL 2 AM EST THURSDAY FOR PAZ065-066.
&&
$$
SYNOPSIS...STEINBUGL
NEAR TERM...STEINBUGL
SHORT TERM...DANGELO
LONG TERM...RXR/TYBURSKI
AVIATION...LA CORTE
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1037 PM EST THU MAR 7 2013
.SYNOPSIS...
COOL AND DRY CANADIAN HIGH PRESSURE WILL REMAIN OVER THE REGION
INTO THE WEEKEND. A COLD FRONT WILL MOVE ACROSS THE REGION LATE
MONDAY REACHING THE COAST BY TUESDAY. ANOTHER DRY HIGH WILL MOVE
INTO THE AREA FOR MID WEEK.
&&
.NEAR TERM /THROUGH FRIDAY/...
AS OF 1035 PM EST THU...BLENDED IN SOME RUC13 WINDS WHICH HAS BUMPED
UP THE SPEEDS A LITTLE OVER THE NRN PART OF THE UPSTATE AND THE SRN
NC PIEDMONT. WINDS ARE RUNNING AROUND 10 KTS IN THESE AREAS ATTM.
OTHERWISE THE SKY GRIDS WERE AGAIN TWEAKED TO CAPTURE THE CURRENT
ORIENTATION OF THE STRATO-CU ALONG THE TN LINE. IT/S MADE SOME
PROGRESS UP THE FRENCH BROAD AND PIGEON RIVER VALLEYS...THOUGH I
DON/T SEE IT GETTING MUCH FURTHER SOUTH. TEMPERATURES WERE LOWERED
AGAIN OVER THE NRN NC FOOTHILLS.
AS OF 755 PM EST THU...ADDED A LITTLE MORE CLOUD COVER RIGHT ALONG
THE TN LINE. ALSO LOWERED HOURLY TEMPS A FEW DEGREES OVER THE NRN
MTNS AND NC FOOTHILLS WHERE TEMPS ARE RUNNING LOWER THAN PREDICTED.
THE REST OF THE GRIDS LOOK TO BE IN GOOD SHAPE.
AS OF 510 PM EST THU...UPDATED SKY GRIDS TO ACCOUNT FOR SHARP
CLEARING LINE ALONG THE TN LINE. UPSTREAM STRATUS HAS BEEN VERY
PERSISTENT AND I HAVE IT HOLDING ON RIGHT ALONG THE LINE FOR SEVERAL
MORE HOURS. THE OTHER 98 PERCENT OF THE FORECAST AREA WILL HAVE A
LOVELY EVENING. TEMPERATURES WERE ALSO ADJUSTED DOWN A FEW DEGREES
OVER THE CENTRAL AND NRN MTNS...MAINLY AS A RESULT OF SNOW COVER.
PREVIOUS DISCUSSION...
THE REGION WILL REMAIN UPSTREAM OF A LONG WAVE TROUGH OFF THE EAST
COAST...WITH HIGH AMPLITUDE RIDGING TO THE WEST THROUGH THE PERIOD.
THIS WILL SUPPORT A RIDGE OF SURFACE HIGH PRESSURE ACROSS THE
REGION. SOME DEGREE OF LOW LEVEL MOISTURE WILL CONTINUE TO SUPPORT
UPSLOPE STRATOCU ALONG THE IMMEDIATE TENN BORDER...AND THIS MAY EVEN
EXPAND A BIT TONIGHT. OTHER THAN THAT...FAIRLY GOOD RADIATIONAL
COOLING CONDITIONS ARE EXPECTED TONIGHT...WHICH SHOULD ALLOW MIN
TEMPS TO COOL TO ABOUT 10 DEGREES BELOW NORMAL.
FRIDAY...THE WESTERN ATLANTIC TROUGH RECEIVES SOME REINFORCEMENT...
AS A POTENT SHORT WAVE DIGS OFF THE MID-ATLANTIC COAST. THIS WILL
SUPPORT CONTINUED LOW THICKNESS VALUES ACROSS OUR AREA...AND MAX
TEMPS WILL BE ONLY MARGINALLY DIFFERENT THAN TODAY/S READINGS.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
AS OF 145 PM THURSDAY...AN UPPER LEVEL RIDGE WILL DOMINATE THE
WEATHER THROUGH THE UPCOMING WEEKEND PROVIDING VERY PLEASANT AND DRY
WEATHER. THE RIDGE AXIS IS FORECAST TO MOVE EAST OF THE APPALACHIANS
BY 12Z SUNDAY. AT THE SFC...A NORTH TO SOUTH ORIENTED HIGH PRESSURE
SYSTEM WILL MOVE FROM THE MID WEST FRIDAY NIGHT...TO OFF THE EAST COAST
ON SUNDAY. THIS WILL RESULT IN MOSTLY CLEAR CONDITIONS THROUGH SAT
NIGHT. THE RETURN FLOW ON THE WESTERN PERIPHERY OF THE HIGH WILL
TRANSPORT INCREASING ATLANTIC MOISTURE INTO THE AREA BEGINNING SAT
NIGHT AND CONTINUING ON SUN. THEREFORE...EXPECT INCREASING AMOUNTS
OF CLOUDS FROM LATE SATURDAY NIGHT INTO SUNDAY.
RIDGING ALOFT AND WARMING LOW LEVEL THICKNESSES SHOULD RESULT IN
ABOVE NORMAL HIGHS BOTH SATURDAY AND SUNDAY. MAX TEMPS SHOULD REACH
THE MID 60S OUTSIDE THE MOUTNAINS...WITH EVEN LOW 60S MOUNTAIN
VALLEYS. GOOD RADIATIONAL COOLING FRI NIGHT WILL ALLOW MIN TEMPS TO
COOL AROUND 5 DEGREES BELOW NORMAL...BUT NEAR TO A LITTLE ABOVE
NORMAL TEMPS SHOULD OCCUR SAT NIGHT AS MOISTURE INCREASES.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 145 PM EST THURSDAY...07/12Z GFS AND 07/00Z ECM ARE IN FAIRLY
GOOD AGREEMENT IN REGARD TO THE PERTINENT WEATHER FEATURES THROUGH
THE MEDIUM RANGE. THE 07/12Z CANADIAN CAME IN AS AN OUTLIER AND WAS
DISREGARDED FOR THIS FORECAST. AN UPPER RIDGE WILL BE MOVING EAST OF
THE AREA AT THE BEGINNING OF THE PERIOD WITH A SHORT WAVE TROUGH
OVER THE MIDWEST. THE UPPER TROUGH IS FORECAST TO MOVE EAST AND
TRAVERSE THE REGION MONDAY NIGHT INTO TUE. THE TROUGH WILL DRIVE A
SURFACE COLD FRONT THROUGH THE AREA. MODEL TIMING FOR THE COLD
FRONTAL PASSAGE IS CONVERGING ON MON NIGHT INTO EARLY TUE. AS
SURFACE HIGH PRESSURE MOVES EAST OF THE AREA SUNDAY NIGHT AND
MON...THE RETURN FLOW WILL TAP INTO ATLANTIC/GULF MOISTURE OUT AHEAD
OF THE COLD FRONT. A FEW SHOWERS COULD DEVELOP OVER WESTERN UPSLOPE
AREAS BY EARLY MON. SHOWERS ARE THEN EXPECTED TO SLOWLY EVERSPREAD
MOST OF THE AREA ON MONDAY FROM WEST TO EAST. THE COLD FRONT WILL
CROSS THE AREA MONDAY NIGHT INTO EARLY TUE. MODERATE AMOUNTS OF
RAINFALL ARE EXPECTED ACROSS THE REGION...MOST LIKELY IN THE HALF
INCH TO INCH RANGE. WITH THE FRONTAL PASSAGE OCCURRING DURING THE
NIGHT...INSTABILITY WILL BE LIMITED SO DO NOT HAVE ANY THUNDER
MENTIONED. ALSO...TEMPERATURES SHOULD BE MILD ENOUGH SO THAT NO
PTYPE ISSUES AREA EXPECTED. THE ONLY EXECEPTION MAY THE ELEVATIONS
ABOVE 3500FT IN THE WAKE OF THE FRONT WHERE THERE COULD BE A BRIEF
PERIOD OF SNOW MIXED WITH RAIN.
BEHIND THE FRONT...DRYING NW FLOW SHOULD COMMENCE SO CLEARING SHOULD
OCCUR WEST TO EAST ACROSS THE AREA ON TUE. HIGH PRESSURE WILL BUILD
TOWARD THE AREA ON WED/THU. 12Z GFS TIME/HEIGHTS SUGGEST LOW LEVEL
MOISTURE MAY BE SUFFICENT FOR MORE CLOUDS ON WED/THU BUT WILL STAY
CLOSER TO THE DRYER ECM SOLUTION AND FORECAST MOSTLY CLEAR/CLEAR SKY
CONDITIONS. TEMPS WILL BEGIN THE PERIOD A LITTLE ABOVE AVERAGE AND
THEN COOL SLIGHTLY BELOW NORMAL BY THE END OF THE PERIOD.
&&
.AVIATION /04Z FRIDAY THROUGH TUESDAY/...
AT KCLT AND ELSEWHERE...CLEAR SKIES THROUGH THE PERIOD. WINDS WILL
GENERALLY BE OUT OF THE NORTH AT 6 TO 8 KTS OVERNIGHT. THE DIRECTION
WILL REMAIN THE SAME ON FRIDAY...THOUGH SOME GUSTS COULD DEVELOP BY
LATE MORNING...ESPECIALLY AT KCLT. I DIDN/T ADD GUSTS TO THIS TAF
PACKAGE...BUT IF THE MOMENTUM XFER LOOKS BETTER ON LATER MODEL
RUNS...THE MID SHIFT MAY NEED TO DO IT.
AT KAVL...GUSTY NW WINDS WILL PERSIST THROUGH AROUND 0300 UTC. AFTER
THAT TIME THE GRADIENT SHOULD SLACKEN ENOUGH FOR THE GUSTS TO STOP
AN FOR THE SUSTAINED WINDS TO FALL UNDER 10 KTS.
OUTLOOK...DRY HIGH PRESSURE WILL PERSIST THROUGH THE WEEKEND.
MOISTURE AND RESTRICTIONS SHOULD RETURN BY LATE MONDAY AHEAD OF THE
NEXT APPROACHING COLD FRONT.
CONFIDENCE TABLE...
03-09Z 09-15Z 15-21Z 21-03Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...PAT
NEAR TERM...JDL/MCAVOY
SHORT TERM...LG
LONG TERM...LG
AVIATION...MCAVOY
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
830 PM CST THU MAR 7 2013
.DISCUSSION.../ISSUED 830 PM CDT/
FORECAST PACKAGE LOOKS ON TRACK FOR THE SHORT TERM WITH ONLY
COSMETIC UPDATES MADE. TEMPERATURES ARE COOLING A BIT SLOWER THAN
FORECAST THIS EVENING WITH CIRRUS STREAM OVERHEAD AND SOUTHEAST FLOW
IN PLACE. STILL A TRICKY FORECAST REGARDING STRATUS DEVELOPMENT LATE
TONIGHT BUT CURRENT THINKING IS LOW STRATUS OVER NORTH DAKOTA WILL
EXPAND SOUTH AND PERHAPS ENTER THE NORTH-WESTERN FRINGE COUNTIES
ALONG AND NORTH OF SURFACE TROUGH LATE TONIGHT. THEN AS THE NEXT
SYSTEM APPROACHES TOMORROW...LOW CLOUDS WILL ADVECT NORTHWARD WITH
INCREASING SOUTHERLY FLOW AND MID-LVL CLOUDS WILL INCREASE FROM THE
SOUTH. /AEB
.PREVIOUS DISCUSSION.../ISSUED AT 333 PM CDT/
FAIRLY QUIET NIGHT AHEAD AS CIRRUS STREAM OVERHEAD AND A SOUTHEAST
GRADUALLY DECREASE THROUGH THE NIGHT. THE MAIN CHALLENGE WILL BE
STRATUS REDEVELOPMENT...MAINLY WHAT TIME. MODELS HAVE NOT BEEN
HANDLING THE LOW LEVEL MOISTURE ALL THAT WELL AS OF LATE AND TONIGHT
LIKELY TO BE NO DIFFERENT. FOR NOW WILL PLAN ON ADDING SOME
REDEVELOPMENT AROUND NORTHWEST IOWA AFTER 6Z AND THEN SPREADING
NORTHWEST THE REMAINDER OF THE NIGHT. THIS SHOULD LEAD TOWARDS A
MOSTLY CLOUDY DAY ON FRIDAY AS WE AWAIT THE WEEKEND WINTER WEATHER
SYSTEM. LOWS TONIGHT WILL BE MILD WITH CLOUDS AND SOUTH WINDS BUT A
FEW LOCATIONS COULD SEE WINDS DROP OFF SO WHILE LOWS WILL MAINLY BE
IN THE 20S A FEW TEENS WILL BE POSSIBLE IN AREAS WITH THINNER CLOUD
COVER AND LIGHT WINDS...LIKELY ALONG HIGHWAY 14. FRIDAY HIGHS WILL
WARM NICELY WITH IN THE SOUTH BUT NOT QUITE AS MUCH IN THE NORTH.
HIGHS SHOULD RANGE FROM THE MID 30S NORTH TO THE MID 40S SOUTH.
UPPER LEVEL SUPPORT AND DEEPER MOISTURE SPREAD NORTH DURING THE DAY
AND COULD SEE THE POTENTIAL FOR SOME SHOWERS TO DEVELOP AFTER ABOUT
21Z. /08
CONTINUE TO SEE THE POTENTIAL FOR PRECIPITATION FROM THIS SYSTEM TO
KICK OFF WITH A LITERAL BANG FRIDAY EVENING. RAPIDLY INCREASING
THERMAL GRADIENT AND INCREASING INSTABILITY FROM THE SOUTH SHOULD
RESULT IN DEVELOPING CONVECTION...INCLUDING A FEW THUNDERSTORMS...TO
AFFECT THE SOUTHEASTERN PART OF THE AREA. THIS CONVECTION SHOULD
SPREAD NORTH/NORTH NORTHEAST FRIDAY NIGHT. THE SHARPENING THERMAL
GRADIENT AND DEVELOPMENT OF THE INVERTED TROUGH INTO THE AREA SHOULD
EVENTUALLY SPAWN WEAKER CONVECTION OVER THE WESTERN PART OF THE
AREA. WITH TEMPERATURES ALOFT TOO WARM FOR SNOW FRIDAY NIGHT...THE
WINTER WEATHER THREAT WILL OF COURSE DEPEND ON SURFACE TEMPERATURES.
THE GREATEST THREAT FOR FREEZING RAIN SEEMS OVER THE NORTH CENTRAL
EDGE OF THE AREA...PERHAPS CENTERED ON BROOKINGS...WHICH THREAT WILL
CONTINUE INTO SATURDAY MORNING. THE THREAT MAY EXTEND TO HURON ON
THE WEST AND TO MARSHALL MN TO THE EAST...THOUGH MARSHALL MAY BE ON
THE FRINGE OF ENOUGH SURFACE WARMING ALONG/EAST OF TROUGH TO
SOMEWHAT MITIGATE ICING. AFTER SATURDAY MORNING THE EVOLUTION OF THE
SYSTEM AND WINTER WEATHER THREAT WILL DEPEND ON HOW WELL MODELS ARE
HANDLING THE SYSTEM. AS WE HAVE GOTTEN CLOSER...THE GFS AND EC HAVE
REVERSED THEIR PATTERNS. THE GFS WHICH WAS SHEARING THE SYSTEM SOUTH
WITH THE NORTHERN STREAM SHORT WAVE NOW GIVES OUR AREA A DECENT
EVENT...AND PERHAPS A POTENTIAL OF A DECENT SNOW ACCUMULATION BAND
OVER PART OF OUR SOUTHEAST INCLUDING FSD. THE NAM IS THE SAME WAY
THOUGH QUITE A BIT FASTER THAN THE GFS. THE EC HOWEVER IS THE ONE
SUPPRESSING THE MAIN SYSTEM NOW. AT THIS TIME OF YEAR WILL GO WITH
THE GFS/NAM WITH A COMPROMISE ON SPEED. POTENTIAL SNOW AND ICE
ACCUMULATIONS SEEM SIGNIFICANT BUT TOO LOW FOR WINTER STORM
CONDITIONS AT THIS TIME SO NO WATCH.
THE PRECIPITATION SHOULD SLOWLY BEGIN TO CHANGE TO SNOW FROM THE
NORTHWEST BY LATE SATURDAY MORNING...THEN THE CHANGEOVER SHOULD
PROGRESS MORE RAPIDLY LATE SATURDAY AND SATURDAY EVENING AS THE MAIN
SYSTEM APPROACHES. SNOW SHOULD THEN DECREASE FROM THE NORTHWEST
SATURDAY NIGHT AND SUNDAY MORNING. WINDS WILL PICK UP SOME BUT NO
GALE...AND WITH LIMITED SNOW AMOUNTS EXPECTED...WILL NOT ADD BLOWING
SNOW AT THIS TIME. TEMPERATURES OF COURSE WILL COOL SATURDAY NIGHT
AND SPEND SUNDAY BELOW FREEZING EVERYWHERE.
MONDAY THROUGH THURSDAY LOOKS DRY AND TURNING MILDER...HAVE DAMPENED
THE EXPECTED WARMING SLIGHTLY BY FROM GUIDANCE THURSDAY AS THE DAY
MODELS ARE SHOWING A MINOR COOL INTRUSION FOR WEDNESDAY BEHIND A
WEAK SYSTEM MOVING EAST NEAR THE CANADIAN BORDER. RIDGING AND
PERHAPS SPRINGLIKE WARMING LOOK LIKE A BETTER BET JUST AFTER THIS
FORECAST PERIOD...PERHAPS TARGETING THE ST. PATRICKS DAY WEEKEND. IN
ANY EVENT...UPPER SUPPORT AND MOISTURE SEEM TOO MEAGER OR
NONEXISTENT FOR ANY PRECIPITATION FOR A WHILE AFTER THIS CURRENT
SYSTEM MOVES OUT SUNDAY.
&&
.AVIATION.../FOR THE 00Z TAF ISSUANCE/
HAVE SIDED WITH MAINLY VFR FORECAST THROUGH 00Z SATURDAY FOR TAF
SITES. EXCEPTION TO THIS IS AT KHON WHERE THERE MAY BE A FEW HOURS
OF IFR STRATUS NEAR SUNRISE. HRRR SOUNDINGS ARE NOT NEAR AS MOIST IN
THE NEAR SURFACE LAYER AS THE NAM OR GFS WOULD SUGGEST...AND
THEREFORE REMOVED STRATUS POTENTIAL FOR KFSD AND KSUX. FAIRLY DENSE
SHIELD OF HIGH CLOUDS ACROSS THE AREA WILL ALSO LIMIT RADIATIVE
COOLING SOME LIMITING THE POTENTIAL FOR LOW CLOUD DEVELOPMENT.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
540 PM CST THU MAR 7 2013
.DISCUSSION.../ISSUED AT 333 PM CDT/
FAIRLY QUIET NIGHT AHEAD AS CIRRUS STREAM OVERHEAD AND A SOUTHEAST
GRADUALLY DECREASE THROUGH THE NIGHT. THE MAIN CHALLENGE WILL BE
STRATUS REDEVELOPMENT...MAINLY WHAT TIME. MODELS HAVE NOT BEEN
HANDLING THE LOW LEVEL MOISTURE ALL THAT WELL AS OF LATE AND TONIGHT
LIKELY TO BE NO DIFFERENT. FOR NOW WILL PLAN ON ADDING SOME
REDEVELOPMENT AROUND NORTHWEST IOWA AFTER 6Z AND THEN SPREADING
NORTHWEST THE REMAINDER OF THE NIGHT. THIS SHOULD LEAD TOWARDS A
MOSTLY CLOUDY DAY ON FRIDAY AS WE AWAIT THE WEEKEND WINTER WEATHER
SYSTEM. LOWS TONIGHT WILL BE MILD WITH CLOUDS AND SOUTH WINDS BUT A
FEW LOCATIONS COULD SEE WINDS DROP OFF SO WHILE LOWS WILL MAINLY BE
IN THE 20S A FEW TEENS WILL BE POSSIBLE IN AREAS WITH THINNER CLOUD
COVER AND LIGHT WINDS...LIKELY ALONG HIGHWAY 14. FRIDAY HIGHS WILL
WARM NICELY WITH IN THE SOUTH BUT NOT QUITE AS MUCH IN THE NORTH.
HIGHS SHOULD RANGE FROM THE MID 30S NORTH TO THE MID 40S SOUTH.
UPPER LEVEL SUPPORT AND DEEPER MOISTURE SPREAD NORTH DURING THE DAY
AND COULD SEE THE POTENTIAL FOR SOME SHOWERS TO DEVELOP AFTER ABOUT
21Z. /08
CONTINUE TO SEE THE POTENTIAL FOR PRECIPITATION FROM THIS SYSTEM TO
KICK OFF WITH A LITERAL BANG FRIDAY EVENING. RAPIDLY INCREASING
THERMAL GRADIENT AND INCREASING INSTABILITY FROM THE SOUTH SHOULD
RESULT IN DEVELOPING CONVECTION...INCLUDING A FEW THUNDERSTORMS...TO
AFFECT THE SOUTHEASTERN PART OF THE AREA. THIS CONVECTION SHOULD
SPREAD NORTH/NORTH NORTHEAST FRIDAY NIGHT. THE SHARPENING THERMAL
GRADIENT AND DEVELOPMENT OF THE INVERTED TROUGH INTO THE AREA SHOULD
EVENTUALLY SPAWN WEAKER CONVECTION OVER THE WESTERN PART OF THE
AREA. WITH TEMPERATURES ALOFT TOO WARM FOR SNOW FRIDAY NIGHT...THE
WINTER WEATHER THREAT WILL OF COURSE DEPEND ON SURFACE TEMPERATURES.
THE GREATEST THREAT FOR FREEZING RAIN SEEMS OVER THE NORTH CENTRAL
EDGE OF THE AREA...PERHAPS CENTERED ON BROOKINGS...WHICH THREAT WILL
CONTINUE INTO SATURDAY MORNING. THE THREAT MAY EXTEND TO HURON ON
THE WEST AND TO MARSHALL MN TO THE EAST...THOUGH MARSHALL MAY BE ON
THE FRINGE OF ENOUGH SURFACE WARMING ALONG/EAST OF TROUGH TO
SOMEWHAT MITIGATE ICING. AFTER SATURDAY MORNING THE EVOLUTION OF THE
SYSTEM AND WINTER WEATHER THREAT WILL DEPEND ON HOW WELL MODELS ARE
HANDLING THE SYSTEM. AS WE HAVE GOTTEN CLOSER...THE GFS AND EC HAVE
REVERSED THEIR PATTERNS. THE GFS WHICH WAS SHEARING THE SYSTEM SOUTH
WITH THE NORTHERN STREAM SHORT WAVE NOW GIVES OUR AREA A DECENT
EVENT...AND PERHAPS A POTENTIAL OF A DECENT SNOW ACCUMULATION BAND
OVER PART OF OUR SOUTHEAST INCLUDING FSD. THE NAM IS THE SAME WAY
THOUGH QUITE A BIT FASTER THAN THE GFS. THE EC HOWEVER IS THE ONE
SUPPRESSING THE MAIN SYSTEM NOW. AT THIS TIME OF YEAR WILL GO WITH
THE GFS/NAM WITH A COMPROMISE ON SPEED. POTENTIAL SNOW AND ICE
ACCUMULATIONS SEEM SIGNIFICANT BUT TOO LOW FOR WINTER STORM
CONDITIONS AT THIS TIME SO NO WATCH.
THE PRECIPITATION SHOULD SLOWLY BEGIN TO CHANGE TO SNOW FROM THE
NORTHWEST BY LATE SATURDAY MORNING...THEN THE CHANGEOVER SHOULD
PROGRESS MORE RAPIDLY LATE SATURDAY AND SATURDAY EVENING AS THE MAIN
SYSTEM APPROACHES. SNOW SHOULD THEN DECREASE FROM THE NORTHWEST
SATURDAY NIGHT AND SUNDAY MORNING. WINDS WILL PICK UP SOME BUT NO
GALE...AND WITH LIMITED SNOW AMOUNTS EXPECTED...WILL NOT ADD BLOWING
SNOW AT THIS TIME. TEMPERATURES OF COURSE WILL COOL SATURDAY NIGHT
AND SPEND SUNDAY BELOW FREEZING EVERYWHERE.
MONDAY THROUGH THURSDAY LOOKS DRY AND TURNING MILDER...HAVE DAMPENED
THE EXPECTED WARMING SLIGHTLY BY FROM GUIDANCE THURSDAY AS THE DAY
MODELS ARE SHOWING A MINOR COOL INTRUSION FOR WEDNESDAY BEHIND A
WEAK SYSTEM MOVING EAST NEAR THE CANADIAN BORDER. RIDGING AND
PERHAPS SPRINGLIKE WARMING LOOK LIKE A BETTER BET JUST AFTER THIS
FORECAST PERIOD...PERHAPS TARGETING THE ST. PATRICKS DAY WEEKEND. IN
ANY EVENT...UPPER SUPPORT AND MOISTURE SEEM TOO MEAGER OR
NONEXISTENT FOR ANY PRECIPITATION FOR A WHILE AFTER THIS CURRENT
SYSTEM MOVES OUT SUNDAY.
&&
.AVIATION.../FOR THE 00Z TAF ISSUANCE/
HAVE SIDED WITH MAINLY VFR FORECAST THROUGH 00Z SATURDAY FOR TAF
SITES. EXCEPTION TO THIS IS AT KHON WHERE THERE MAY BE A FEW HOURS
OF IFR STRATUS NEAR SUNRISE. HRRR SOUNDINGS ARE NOT NEAR AS MOIST IN
THE NEAR SURFACE LAYER AS THE NAM OR GFS WOULD SUGGEST...AND
THEREFORE REMOVED STRATUS POTENTIAL FOR KFSD AND KSUX. FAIRLY DENSE
SHIELD OF HIGH CLOUDS ACROSS THE AREA WILL ALSO LIMIT RADIATIVE
COOLING SOME LIMITING THE POTENTIAL FOR LOW CLOUD DEVELOPMENT.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
350 PM CST WED MAR 6 2013
.DISCUSSION.../ISSUED AT 350 PM CST/
CHALLENGES TONIGHT AND TOMORROW FOCUS ON STRATUS...OR POSSIBLY A
LACK THERE OF. THIS IS NOT AN EASY ONE TO ANSWER TONIGHT AS THE
STRATUS IS QUICKLY ERODING FROM THE SOUTHWEST TODAY AND WITH AN
INCREASED SOUTHERLY GRADIENT OVERNIGHT INDICATIONS ARE THAT IT MAY
REMAIN AT BAY IN LOCATIONS WHERE IT ERODES. HOWEVER...IF SOME OF
THESE BETTER WINDS ALOFT DO NOT MIX DOWN AN ALREADY STRONG INVERSION
MAY GET A LITTLE STRONGER THROUGH THE NIGHT ALLOWING STRATUS TO
REDEVELOP FROM THE EAST AND SOUTHEAST. SO REALLY COULD SEE EITHER
SOLUTION OCCURRING. SO...BECAUSE OF A LACK OF CONFIDENCE WILL NOT
CHANGE LOWS MUCH BUT IF THE FAR EASTERN CWA REMAINS CLOUDY ALL NIGHT
THE LOWS WILL PROBABLY BE A LITTLE WARMER THAN FORECAST.
A BIT BREEZY ON THURSDAY AS THE WINDS PICK UP FROM THE SOUTHEAST.
WILL KEEP TEMPERATURES IN THE LOWER TO MIDDLE 30S OVER EXISTING SNOW
COVER WHILE AREAS WITH NO SNOW IN SOUTH CENTRAL SOUTH DAKOTA SHOULD
EASILY REACH THE MID 40S. /08
THURSDAY NIGHT AND FRIDAY SHOULD BE RELATIVELY MILD WITH MOST OF THE
CLOUD INCREASE AHEAD OF APPROACHING SYSTEM COMING VERY LATE
THURSDAY NIGHT AND FRIDAY. AT THIS TIME DO NOT SEE PRECIPITATION
DEVELOPING UNTIL EARLY FRIDAY EVENING...BUT IT COULD DEVELOP RAPIDLY
AT THAT TIME. THE PRESENCE OF A STRENGTHENING FRONTAL BOUNDARY...
MOISTURE ADVECTION...AND DESTABILIZATION IS EXPECTED TO BRING
SHOWERY RAINS AND MAYBE EVEN THUNDERSTORMS SOUTHEAST...WITH LESS
CONVECTIVE BUT STILL VARIABLY INTENSITY PRECIPITATION NORTHWEST.
WARMING AHEAD OF THIS SYSTEM SHOULD PRECLUDE SNOW EVEN
NORTHWEST...BUT LOW LEVEL COOLING SEEMS LIKELY NORTH AND NORTHWEST
OF THE FRONT AS IT QUICKLY STRENGTHENS...AND THIS ADDS UP TO A
SIGNIFICANT FREEZING RAIN THREAT NORTH AND WEST. THIS THREAT SHOULD
CONTINUE SATURDAY AND BEGIN SHIFTING SOUTHEAST...WHILE SNOW DEVELOPS
GRADUALLY FROM THE NORTHWEST AS DYNAMIC AND EVAPORATIONAL COOLING
GAIN SWAY WITH THE APPROACH OF UPPER LOW FROM THE SOUTHWEST AND
NORTHERN STREAM UPPER TROUGH. SOME PRECIPITATION...MAINLY
SNOW...SHOULD CONTINUE INTO SUNDAY. AT THIS TIME THE FREEZING RAIN
SEEMS LIKE THE MAIN WINTER WEATHER THREAT AS THE UPPER LOW WILL
START TO BE DRIVEN MORE EAST NORTHEAST WITH TIME. THIS MEANS MOST OF
THE PRECIPITATION WILL OCCUR EARLY IN THE EVENT FROM THE GREATLY
SHARPENING THERMAL GRADIENT AND INSTABILITY. THE MORE DYNAMICALLY
RELATED PRECIPITATION LATER ON...AFTER UPPER COOLING...MAY NOT BE
TOO GREAT WITH THIS DIVERTING OF THE UPPER LOW. DESPITE DIFFERENCES
FROM YESTERDAYS RUNS...YESTERDAYS ACTION OF CUTTING OFF THE
PRECIPITATION FROM EARLY NEXT WEEK LOOKS TO BE TURNING OUT VERY
WELL. MONDAY THROUGH WEDNESDAY SHOULD BE DRY AND WITHIN SHOUTING
DISTANCE OF SEASONABLE...A BIT BELOW IT AT THE START...AS THE UPPER
RIDGING MOVES IN FROM THE WEST. THE KIND OF COLD OUTLOOK FOR THE
LONG RANGE AFTER OUR FORECAST PERIOD FROM EARLIER IN THE WEEK SEEMS
TO BE TURNING MILDER.
&&
.AVIATION.../FOR THE 18Z TAF ISSUANCE/
QUICKLY LOOPING THROUGH THE VISIBLE SATELLITE SHOWS THAT THE
EXISTING STRATUS IS PRETTY THIN AND AT THIS TIME FAIRLY QUICKLY
ERODING FROM THE SOUTHWEST. THE RAP HAS US MIRED IN THE GUNK THROUGH
LATE TONIGHT WHILE THE OTHER MODELS TEMPORARILY BREAK US OUT OF THE
LOW END MVFR CEILINGS...THEN SUGGEST REDEVELOPMENT LATER TONIGHT. NO
EASY ANSWER HERE AS SOME QUESTION THAT IF STRATUS IS ABLE TO
DISSIPATE THIS AFTERNOON AN INCREASING SOUTHERLY GRADIENT MAY MAKE
IT DIFFICULT TO REDEVELOP. HOWEVER...WILL LEAN TOWARDS THE MORE
PESSIMISTIC SOLUTION AND PLAN ON THE STRATUS REDEVELOPING UNDER A
FAIRLY STRONG INVERSION AND THINKING MVFR TO IFR CEILINGS OVERNIGHT
MOST LOCATIONS. /08
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
130 PM CST WED MAR 6 2013
.DISCUSSION.../ISSUED AT 445 AM CST/
LOOKS LIKE A QUIET COUPLE OF DAYS ACROSS THE REGION...BUT THAT DOES
NOT MEAN THE FORECAST IS WITHOUT ITS CHALLENGES. OF PRIMARY CONCERN
TODAY IS WIDESPREAD STRATUS WHICH IS NOW STUCK UNDER SURFACE RIDGE
ADVANCING SLOWLY EASTWARD TODAY. OTHER THAN HIGH-RESOLUTION SHORT
RANGE MODELS...WHICH SEEM TO HAVE BETTER GRASP ON CURRENT REALITY...
HAVE LITTLE USEFUL GUIDANCE TO FOLLOW REGARDING PERSISTENCE OF THE
LOW LEVEL MOISTURE. THUS FOLLOWED MORE PESSIMISTIC RAP/HRRR VIEW...
HOLDING ONTO EXTENSIVE CLOUD COVER MUCH OF THE DAY WITH POSSIBILITY
OF SOME HOLES DEVELOPING IN THE LATE AFTERNOON AS MARCH SUN HAS A
CHANCE TO ERODE AROUND ANY BREAKS WHICH MAY DEVELOP. GREATER CLOUD
COVER WILL LEAD TO COOLER TEMPS...THOUGH PREVIOUS FORECAST ALREADY
ON THE COOL SIDE WITH LIGHT FLOW ACROSS THE EAST SO DID NOT LOWER
HIGHS TOO MUCH AT THIS POINT.
FOR TONIGHT...NAM LOW LEVEL MOISTURE HINTS AT POTENTIAL FOR STRATUS
TO REDEVELOP ACROSS CENTRAL SD AS RETURN SOUTHERLY FLOW DRAWS DEEPER
MOISTURE NORTHWARD BEHIND THE DEPARTING RIDGE. IF THIS DOES DEVELOP
IT COULD LINGER INTO AT LEAST MIDDAY THURSDAY...AGAIN IMPACTING HIGH
TEMPERATURES AND COOLED HIGHS IN THE WEST BY A FEW DEGREES...THOUGH
WITH 925MB TEMPERATURES ANYWHERE FROM 4-6C...COULD STILL MIX INTO
THE MID TO UPPER 40S WEST OF THE JAMES RIVER.
ATTENTION THEN TURNS TO WEEKEND SYSTEM...WHICH MODELS HAVE COME INTO
SLIGHTLY BETTER AGREEMENT ON WHEN COMPARED TO PAST COUPLE OF NIGHTS.
FAVORED SOLUTION DEPICTS STRONGER BUT PROGRESSIVE NORTHERN STREAM
TROUGH MOVING EAST ACROSS NORTH DAKOTA/MINNESOTA SATURDAY/SATURDAY
NIGHT...WHICH DOES NOT ALLOW SOUTHERN STREAM CUTOFF LOW TO SWING
NORTH AND STRENGTHEN AS HAS BEEN SEEN IN PREVIOUS ECMWF RUNS. THIS
SOLUTION DOES GIVE THIS AREA A GOOD CHANCE OF SOME DECENT PRECIP...
WITH GOOD CONSENSUS POINTING TO LATE FRIDAY NIGHT THROUGH SATURDAY
NIGHT AS PERIODS WITH GREATEST POTENTIAL.
COULD SEE SOME LIGHT PRECIP BREAK OUT ACROSS THE WEST ALREADY BY
FRIDAY AFTERNOON...AS BROAD WARM ADVECTION BEGINS TO KICK IN. THIS
BROAD LIFT ACROSS INVERTED TROUGH REMAINS PERSISTENT INTO FRIDAY
NIGHT...WITH GROWING CONFIDENCE FOR BUMPING POPS INTO LIKELY RANGE
ACROSS MUCH OF THE AREA LATE FRIDAY NIGHT AND SATURDAY. WILL CARRY
LIKELY POPS INTO SATURDAY NIGHT OVER THE SOUTHEAST HALF OF THE CWA
AS BOUNDARY IS PULLED EAST OF THE AREA BY DEPARTING NORTHERN STREAM
WAVE.
WHILE CONFIDENCE IN PRECIPITATION CHANCE IS GROWING...PRECIPITATION
TYPE BECOMES A HUGE QUESTION MARK. GFS/ECMWF BOTH PUMP WARM AIR WELL
NORTH ACROSS THE REGION...WITH FREEZING LINE NEAR ND/SD BORDER AT
850MB...AND NEAR THE NORTHERN EDGE OF OUR FORECAST AREA AT 925MB BY
FRIDAY EVENING. CONTINUED SOUTHERLY FLOW ACROSS THE AREA FRIDAY
NIGHT KEEPS THE WARM LAYER LOCKED IN PLACE AT LEAST INTO SATURDAY
MORNING...WITH COOLING ONLY TAKING PLACE IN THE WEST BY SATURDAY
AFTERNOON/EVENING AS INVERTED TROUGH BEGINS TO ADVANCE EASTWARD.
SURFACE TEMPERATURES THEN BECOME FOCUS AND FOR NOW HAVE SUB-FREEZING
TEMPERATURES ACROSS FAR WESTERN AND NORTHERN CWA FRIDAY NIGHT INTO
SATURDAY...WITH COLD AIR COLLAPSING SOUTHWARD SATURDAY NIGHT BEHIND
DEPARTING TROUGH. FORECAST SOUNDINGS SUGGEST POTENTIAL FOR FREEZING
RAIN IN THE FAR NORTHERN/WESTERN SECTIONS GIVEN THE COLDER SURFACE
TEMPERATURES TOPPED BY WARM LAYER ABOVE 925MB. HOWEVER...STILL HAVE
ENOUGH UNCERTAINTY IN LOW LEVEL TEMPS AT THIS RANGE THAT DECIDED TO
HOLD OFF MENTIONING FREEZING RAIN FOR NOW...INSTEAD GOING WITH RAIN
OR SNOW WORDING ACROSS OUR NORTH AND WEST...GENERALLY IN THOSE AREAS
NORTHWEST OF INVERTED TROUGH. WILL ADD MENTION OF FREEZING RAIN TO
THE HWO THIS MORNING THOUGH...TO HEIGHTEN AWARENESS OF POTENTIAL FOR
ICING GIVEN TIMING OF THIS EVENT COINCIDING WITH SOUTH DAKOTA GIRLS
BASKETBALL TOURNAMENT TAKING PLACE IN VARIOUS LOCATIONS INCLUDING
HURON THIS WEEKEND.
BY SATURDAY NIGHT/SUNDAY...COOLING BEHIND THE SYSTEM SHOULD CHANGE
PRECIP OVER TO SNOW...THOUGH PRECIP SHOULD ALSO BE WANING THROUGH
THAT PERIOD SO NOT EXPECTING LARGE AMOUNTS OF SNOWFALL AT THIS TIME.
GENERALLY QUIET WEATHER RETURNS FOR EARLY NEXT WEEK. COULD SEE SOME
LIGHT PRECIP IN NORTHWEST FLOW PATTERN...BUT GIVEN SOME UNCERTAINTY
IN PATTERN AND AVAILABLE MOISTURE...WILL KEEP DRY FOR NOW WITH
TEMPERATURES REMAINING ON THE COOL SIDE OF SEASONAL NORMALS.
&&
.AVIATION.../FOR THE 18Z TAF ISSUANCE/
QUICKLY LOOPING THROUGH THE VISIBLE SATELLITE SHOWS THAT THE
EXISTING STRATUS IS PRETTY THIN AND AT THIS TIME FAIRLY QUICKLY
ERODING FROM THE SOUTHWEST. THE RAP HAS US MIRED IN THE GUNK THROUGH
LATE TONIGHT WHILE THE OTHER MODELS TEMPORARILY BREAK US OUT OF THE
LOW END MVFR CEILINGS...THEN SUGGEST REDEVELOPMENT LATER TONIGHT. NO
EASY ANSWER HERE AS SOME QUESTION THAT IF STRATUS IS ABLE TO
DISSIPATE THIS AFTERNOON AN INCREASING SOUTHERLY GRADIENT MAY MAKE
IT DIFFICULT TO REDEVELOP. HOWEVER...WILL LEAN TOWARDS THE MORE
PESSIMISTIC SOLUTION AND PLAN ON THE STRATUS REDEVELOPING UNDER A
FAIRLY STRONG INVERSION AND THINKING MVFR TO IFR CEILINGS OVERNIGHT
MOST LOCATIONS. /08
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
445 AM CST WED MAR 6 2013
.DISCUSSION.../ISSUED AT 445 AM CST/
LOOKS LIKE A QUIET COUPLE OF DAYS ACROSS THE REGION...BUT THAT DOES
NOT MEAN THE FORECAST IS WITHOUT ITS CHALLENGES. OF PRIMARY CONCERN
TODAY IS WIDESPREAD STRATUS WHICH IS NOW STUCK UNDER SURFACE RIDGE
ADVANCING SLOWLY EASTWARD TODAY. OTHER THAN HIGH-RESOLUTION SHORT
RANGE MODELS...WHICH SEEM TO HAVE BETTER GRASP ON CURRENT REALITY...
HAVE LITTLE USEFUL GUIDANCE TO FOLLOW REGARDING PERSISTENCE OF THE
LOW LEVEL MOISTURE. THUS FOLLOWED MORE PESSIMISTIC RAP/HRRR VIEW...
HOLDING ONTO EXTENSIVE CLOUD COVER MUCH OF THE DAY WITH POSSIBILITY
OF SOME HOLES DEVELOPING IN THE LATE AFTERNOON AS MARCH SUN HAS A
CHANCE TO ERODE AROUND ANY BREAKS WHICH MAY DEVELOP. GREATER CLOUD
COVER WILL LEAD TO COOLER TEMPS...THOUGH PREVIOUS FORECAST ALREADY
ON THE COOL SIDE WITH LIGHT FLOW ACROSS THE EAST SO DID NOT LOWER
HIGHS TOO MUCH AT THIS POINT.
FOR TONIGHT...NAM LOW LEVEL MOISTURE HINTS AT POTENTIAL FOR STRATUS
TO REDEVELOP ACROSS CENTRAL SD AS RETURN SOUTHERLY FLOW DRAWS DEEPER
MOISTURE NORTHWARD BEHIND THE DEPARTING RIDGE. IF THIS DOES DEVELOP
IT COULD LINGER INTO AT LEAST MIDDAY THURSDAY...AGAIN IMPACTING HIGH
TEMPERATURES AND COOLED HIGHS IN THE WEST BY A FEW DEGREES...THOUGH
WITH 925MB TEMPERATURES ANYWHERE FROM 4-6C...COULD STILL MIX INTO
THE MID TO UPPER 40S WEST OF THE JAMES RIVER.
ATTENTION THEN TURNS TO WEEKEND SYSTEM...WHICH MODELS HAVE COME INTO
SLIGHTLY BETTER AGREEMENT ON WHEN COMPARED TO PAST COUPLE OF NIGHTS.
FAVORED SOLUTION DEPICTS STRONGER BUT PROGRESSIVE NORTHERN STREAM
TROUGH MOVING EAST ACROSS NORTH DAKOTA/MINNESOTA SATURDAY/SATURDAY
NIGHT...WHICH DOES NOT ALLOW SOUTHERN STREAM CUTOFF LOW TO SWING
NORTH AND STRENGTHEN AS HAS BEEN SEEN IN PREVIOUS ECMWF RUNS. THIS
SOLUTION DOES GIVE THIS AREA A GOOD CHANCE OF SOME DECENT PRECIP...
WITH GOOD CONSENSUS POINTING TO LATE FRIDAY NIGHT THROUGH SATURDAY
NIGHT AS PERIODS WITH GREATEST POTENTIAL.
COULD SEE SOME LIGHT PRECIP BREAK OUT ACROSS THE WEST ALREADY BY
FRIDAY AFTERNOON...AS BROAD WARM ADVECTION BEGINS TO KICK IN. THIS
BROAD LIFT ACROSS INVERTED TROUGH REMAINS PERSISTENT INTO FRIDAY
NIGHT...WITH GROWING CONFIDENCE FOR BUMPING POPS INTO LIKELY RANGE
ACROSS MUCH OF THE AREA LATE FRIDAY NIGHT AND SATURDAY. WILL CARRY
LIKELY POPS INTO SATURDAY NIGHT OVER THE SOUTHEAST HALF OF THE CWA
AS BOUNDARY IS PULLED EAST OF THE AREA BY DEPARTING NORTHERN STREAM
WAVE.
WHILE CONFIDENCE IN PRECIPITATION CHANCE IS GROWING...PRECIPITATION
TYPE BECOMES A HUGE QUESTION MARK. GFS/ECMWF BOTH PUMP WARM AIR WELL
NORTH ACROSS THE REGION...WITH FREEZING LINE NEAR ND/SD BORDER AT
850MB...AND NEAR THE NORTHERN EDGE OF OUR FORECAST AREA AT 925MB BY
FRIDAY EVENING. CONTINUED SOUTHERLY FLOW ACROSS THE AREA FRIDAY
NIGHT KEEPS THE WARM LAYER LOCKED IN PLACE AT LEAST INTO SATURDAY
MORNING...WITH COOLING ONLY TAKING PLACE IN THE WEST BY SATURDAY
AFTERNOON/EVENING AS INVERTED TROUGH BEGINS TO ADVANCE EASTWARD.
SURFACE TEMPERATURES THEN BECOME FOCUS AND FOR NOW HAVE SUB-FREEZING
TEMPERATURES ACROSS FAR WESTERN AND NORTHERN CWA FRIDAY NIGHT INTO
SATURDAY...WITH COLD AIR COLLAPSING SOUTHWARD SATURDAY NIGHT BEHIND
DEPARTING TROUGH. FORECAST SOUNDINGS SUGGEST POTENTIAL FOR FREEZING
RAIN IN THE FAR NORTHERN/WESTERN SECTIONS GIVEN THE COLDER SURFACE
TEMPERATURES TOPPED BY WARM LAYER ABOVE 925MB. HOWEVER...STILL HAVE
ENOUGH UNCERTAINTY IN LOW LEVEL TEMPS AT THIS RANGE THAT DECIDED TO
HOLD OFF MENTIONING FREEZING RAIN FOR NOW...INSTEAD GOING WITH RAIN
OR SNOW WORDING ACROSS OUR NORTH AND WEST...GENERALLY IN THOSE AREAS
NORTHWEST OF INVERTED TROUGH. WILL ADD MENTION OF FREEZING RAIN TO
THE HWO THIS MORNING THOUGH...TO HEIGHTEN AWARENESS OF POTENTIAL FOR
ICING GIVEN TIMING OF THIS EVENT COINCIDING WITH SOUTH DAKOTA GIRLS
BASKETBALL TOURNAMENT TAKING PLACE IN VARIOUS LOCATIONS INCLUDING
HURON THIS WEEKEND.
BY SATURDAY NIGHT/SUNDAY...COOLING BEHIND THE SYSTEM SHOULD CHANGE
PRECIP OVER TO SNOW...THOUGH PRECIP SHOULD ALSO BE WANING THROUGH
THAT PERIOD SO NOT EXPECTING LARGE AMOUNTS OF SNOWFALL AT THIS TIME.
GENERALLY QUIET WEATHER RETURNS FOR EARLY NEXT WEEK. COULD SEE SOME
LIGHT PRECIP IN NORTHWEST FLOW PATTERN...BUT GIVEN SOME UNCERTAINTY
IN PATTERN AND AVAILABLE MOISTURE...WILL KEEP DRY FOR NOW WITH
TEMPERATURES REMAINING ON THE COOL SIDE OF SEASONAL NORMALS.
&&
.AVIATION.../FOR THE 06Z TAF ISSUANCE/
STRATUS HAS CONTINUED TO EXPAND WITH DECREASING WINDS AND DIRECTION
BECOMING MORE NORTHEASTERLY. MODELS NOT HANDLING THE STRATUS WELL
AT ALL...WITH THE RAP BEING THE ONLY MODEL SUGGESTING STRATUS
CURRENTLY EXISTS ACROSS THE AREA. HAVE KEPT STRATUS ACROSS THE AREA
THROUGH THE OVERNIGHT...WITH CEILINGS LOWERING SLIGHTLY AROUND
SUNRISE. MODEL SOUNDINGS SUGGEST OUTSIDE CHANCE OF STRATUS LOWERING
TO THE GROUND NEAR KHON...BUT CONFIDENCE NOT THERE AT THIS POINT TO
PUT INTO THE TAF. AT KFSD AND KSUX...STRATUS MAY DIP INTO THE IFR
RANGE BEFORE RECOVERING INTO THE MVFR CATEGORY. WILL BE HARD TO
SHAKE THE STRATUS TOMORROW WITH LIGHT SOUTHEASTERLY FLOW
DEVELOPING...AND KEPT STRATUS THROUGHOUT THE DAY. SOUNDINGS DON/T
HAVE MUCH TO WORK OFF OF BY TOMORROW EVENING...BUT KEPT STRATUS WITH
REINFORCING SOUTHEASTERLY FLOW.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1050 PM CST TUE MAR 5 2013
.DISCUSSION.../ISSUED AT 840 PM CST/
LARGE SWATH OF LOW STRATUS REMAINS LARGELY UNCHANGED FROM THIS
AFTERNOON...AS THE LOW LEVEL NORTH NORTHWEST FLOW CONTINUES TO
STREAM THE STRATUS ACROSS THE FORECAST AREA. SOME THINNING IS
OBSERVED ACROSS SOUTH CENTRAL SOUTH DAKOTA AND FAR NORTHEAST
NEBRASKA...BUT OVERALL...DO NOT ANTICIPATE MUCH IF ANY PUSH EASTWARD
TONIGHT. COULD SEE SOME THINNING IN THE WEST LATE TONIGHT AS THE
SURFACE RIDGE TRACKS THROUGH THE REGION...BUT WITH SUCH LIGHT FLOW
WE COULD VERY WELL SEE THE STRATUS HANG ON THROUGH WEDNESDAY
MORNING. WITH THE BULK OF THE FORECAST AREA LIKELY TO SEE
CONSIDERABLE CLOUD COVERAGE OVERNIGHT...HAVE RAISED LOWS A FEW
DEGREES.
&&
.AVIATION.../FOR THE 06Z TAF ISSUANCE/
STRATUS HAS CONTINUED TO EXPAND WITH DECREASING WINDS AND DIRECTION
BECOMING MORE NORTHEASTERLY. MODELS NOT HANDLING THE STRATUS WELL
AT ALL...WITH THE RAP BEING THE ONLY MODEL SUGGESTING STRATUS
CURRENTLY EXISTS ACROSS THE AREA. HAVE KEPT STRATUS ACROSS THE AREA
THROUGH THE OVERNIGHT...WITH CEILINGS LOWERING SLIGHTLY AROUND
SUNRISE. MODEL SOUNDINGS SUGGEST OUTSIDE CHANCE OF STRATUS LOWERING
TO THE GROUND NEAR KHON...BUT CONFIDENCE NOT THERE AT THIS POINT TO
PUT INTO THE TAF. AT KFSD AND KSUX...STRATUS MAY DIP INTO THE IFR
RANGE BEFORE RECOVERING INTO THE MVFR CATEGORY. WILL BE HARD TO
SHAKE THE STRATUS TOMORROW WITH LIGHT SOUTHEASTERLY FLOW
DEVELOPING...AND KEPT STRATUS THROUGHOUT THE DAY. SOUNDINGS DON/T
HAVE MUCH TO WORK OFF OF BY TOMORROW EVENING...BUT KEPT STRATUS WITH
REINFORCING SOUTHEASTERLY FLOW.
&&
.PREV DISCUSSION.../ISSUED AT 300 PM CST/
WIDESPREAD STRATUS ALONG AND EAST OF THE JAMES RIVER WILL BE SLOW TO
CLEAR FROM WEST TO EAST OVERNIGHT. MODELS APPEAR TOO FAST IN
CLEARING THE STRATUS OUT AND WILL KEEP AREAS EAST OF I29 MOSTLY
CLOUDY OVERNIGHT WITH CLEARING TOWARDS MORNING. THIS SHOULD ALSO
HELP HOLD TEMPERATURES UP ACROSS THE EAST AND HAVE BUMPED LOWS UP
THERE 2 TO 4 DEGREES. THE BIG QUESTION FOR WEDNESDAY WILL BE THE
CLOUD COVER. IF STRATUS DOES NOT CLEAR ACROSS THE EAST LATER
TONIGHT...WEAK LOW LEVEL EASTERLY FLOW ON WEDNESDAY MAY KEEP THE
STRATUS IN ALL DAY AND WILL HOLD THE TEMPERATURES DOWN. AM NOT
CONFIDENT CLEARING WILL OCCUR SO WILL BE A TAD BIT MORE PESSIMISTIC
AND GO WITH PARTLY CLOUDY ACROSS THE EAST. WILL KEEP HIGHS GENERALLY
IN THE 20S EAST OF I29 AND IN THE 30S TO LOWER 40S WEST WITH THE
WARMEST TEMPERATURES ACROSS THE SOUTHWEST CWA.
EXPECT SKIES SHOULD FINALLY GO MOSTLY CLEAR...FOR A SPELL...
WEDNESDAY NIGHT AS SUBSIDENCE FROM THE HIGH AND A LIGHT EASTERLY
FLOW OF DRY AIR STARTING AS THE HIGH MOVES EAST WORK TOGETHER.
CLOUDS...THEY SHOULD BE MIDDLE AND HIGH...SHOULD LATER WORK THEIR
WAY SLOWLY BACK OVER THE AREA THURSDAY THROUGH FRIDAY IN WARMING
PATTERN. NO PRECIPITATION THREAT SEEN THESE TWO DAYS THROUGH FRIDAY
AFTERNOON. TEMPERATURES WILL WARM THOUGH SURFACE WARMING WILL LIKELY
BE LIMITED AS THE LOW LEVEL FLOW BEGINS TO BACK AGAIN TO MORE
EASTERLY FRIDAY AFTER GOING SOUTHERLY. GUIDANCE TEMPERATURES DO NOT
LOOK BAD. FOR NOW...CLOUD COVER AND DEVELOPING EASTERLY/SOUTHEAST
FLOW IS EXPECTED TO LIMIT THE CHANCE OF ANY LATE NIGHT FOG AFTER
DAYTIME SNOWMELT SO WILL KEEP OUT.
MEDIUM RANGE MODELS HAVE...FOR NOW...REACHED A CONSENSUS ON A
STRONGER CANADIAN NORTHERN STREAM KEEPING POTENTIALLY WET WEEKEND
SYSTEM MOSTLY TO THE SOUTH OF OUR AREA. THE EC IN PARTICULAR HAD
BEEN GOING ON THE NORTHERN TRACK AND WET SIDE FOR OUR AREA UP TO
TODAY. HAVE REACHED AGREEMENT WITH NEIGHBORS ON KEEPING PRECIP
MENTION BUT LOWERING POPS SOME FOR THE WEEKEND...THEN ALLOW FOR THE
CHASING OUT OF THE SYSTEM BY THE START OF NEXT WEEK. THE CANADIAN
RIDGING PARTLY RESPONSIBLE FOR THIS CHANGE SHOULD ALSO KEEP
TEMPERATURES TO NEAR SEASONAL LEVELS...THOUGH THIS WILL BE A LOT
COOLER THAN THE RECORD SMASHING TEMPERATURES WE WERE GETTING AT THE
SAME TIME LAST YEAR. NOT TIME FOR GOLF...YET.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
REFER TO THE MAIN FORECAST DISCUSSION SECTION FOR MORE ABOUT SKY
COVER TONIGHT.
EXPECT MVFR CLOUDS TO VERY GRADUALLY ERODE AWAY FROM WEST TO EAST
OVERNIGHT...ALTHOUGH THERE IS A LOT OF UNCERTAINTY ABOUT THE SPEED
OF THE CLEARING...IF IT OCCURS AT ALL. IF SKIES CLEAR...PATCHY FOG
WILL BE POSSIBLE. MAINLY CLEAR SKIES/VFR CONDITIONS EXPECTED
THURSDAY.
&&
.MARINE...
NORTHWEST WINDS IN THE NSH WATERS HAVE DIMINISHED BELOW
SMALL CRAFT ADVISORY CRITERIA. WILL ALLOW THE ADVY TO EXPIRE FOR THE
NORTHERN NEARSHORE MARINE ZONES...AND KEEP THE SOUTHERN ONE THROUGH
6 PM DUE TO LINGERING LARGE WAVES TOWARD THE OPEN WATERS.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 6 PM CST THIS EVENING FOR LMZ645-646.
SMALL CRAFT ADVISORY UNTIL 4 PM CST THIS AFTERNOON FOR LMZ643-
644.
&&
$$
TONIGHT/THURSDAY AND AVIATION/MARINE...MRC
THURSDAY NIGHT THROUGH WEDNESDAY...MEB
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1213 PM CST WED MAR 6 2013
.SHORT TERM...TODAY THROUGH FRIDAY
328 AM CST WED MAR 6 2013
FORECAST CONCERNS ARE ON FOG/FREEZING FOG POTENTIAL TONIGHT INTO
THURSDAY MORNING AND TEMPERATURES THROUGH FRIDAY. FOCUS THEN QUICKLY
TURNS TO PRECIPITATION TYPE CONCERNS THIS WEEKEND AND THE POTENTIAL
FOR MODERATE TO HEAVY RAINFALL ACROSS PARTS OF THE AREA.
LATEST WATER VAPOR IMAGERY AND 500 MB RAP ANALYSIS SHOWED LOW
PRESSURE OVER THE CENTRAL APPALACHIANS. A TROUGH WAS NOTED ALONG
THE MINNESOTA/ONTARIO BORDER. AN UPPER RIDGE WAS BUILDING ACROSS
THE WESTERN CONUS WITH A TROUGH MOVING ONTO THE WEST COAST. SURFACE
OBSERVATIONS INDICATED A RIDGE OF HIGH PRESSURE EXTENDING FROM THE
THE DAKOTAS SOUTH THROUGH THE SOUTHERN PLAINS. A SURFACE LOW WAS
NOTED OVER VIRGINIA WITH AN INVERTED TROUGH EXTENDING NORTHWEST
INTO FAR SOUTHEAST WISCONSIN.
THE TROUGH ALONG THE MINNESOTA/ONTARIO BORDER WILL PROGRESS EAST
TODAY ACROSS LAKE SUPERIOR AS THE SURFACE RIDGE EDGES EAST INTO
THE UPPER MISSISSIPPI RIVER VALLEY. THE MAIN FORECAST CHALLENGE
TODAY WILL BE CLOUD COVER. THERE ARE CURRENTLY PLENTY OF HOLES IN
THE STRATUS LAYER OVER EASTERN MINNESOTA INTO SOUTHWEST WISCONSIN.
FORECAST SOUNDINGS SHOW LOW LEVEL CLOUDS LINGERING THROUGH THE
MORNING HOURS BEFORE FINALLY CLEARING LATE THIS AFTERNOON. THE
FORECAST MODELS HAVE BEEN STRUGGLING WITH DEWPOINTS LATELY SO NOT
SOLD ON THE CLOUDS HOLDING ON AS LONG AS THE MODELS SUGGEST.
DECIDED TO GO WITH HIGHER CLOUD COVER THIS MORNING OVER THE
PREVIOUS FORECAST...WITH CLEARING OCCURRING FROM WEST TO EAST
DURING THE MID TO LATE AFTERNOON HOURS. THE NEXT CONCERN IS THE
POTENTIAL FOR FOG/FREEZING FOG TONIGHT. FOG WOULD BE MORE
FAVORABLE IF THE CLOUDS HOLD ON TODAY. SREF GUIDANCE AND FORECAST
SOUNDINGS CONTINUE TO SUGGEST FOG DEVELOPMENT TONIGHT. LOOKING
BACK TO THE WEST...UNDER THE SURFACE RIDGE...FOG HAS DEVELOPED.
THE SREF PROBABILITIES ARE CAPTURING THIS SO FEEL THEY ARE DOING A
DECENT JOB ON CAPTURING THE FOG. WILL MAINTAIN AREAS OF FOG IN THE
FORECAST OVERNIGHT INTO THURSDAY MORNING. VISIBILITIES COULD BE
REDUCED TO LESS THAN 1/2 MILE. ALSO...THE FOG COULD FREEZE TO
OBJECTS CREATING HOAR FROST. SOME LIGHT ICING MAY OCCUR ON AREA
ROADS...BUT THE RECENTLY APPLIED TREATMENT ON THE ROADS COULD
REALLY LIMIT ICING POTENTIAL. PLAN ON LOWS FALLING INTO THE SINGLE
DIGITS TONIGHT. FAVORED COLD SPOTS ACROSS CENTRAL INTO NORTH
CENTRAL WISCONSIN WILL SEE TEMPERATURES FALL INTO THE SINGLE DIGITS
BELOW ZERO.
HIGH PRESSURE WILL BE IN CONTROL ACROSS THE REGION ON THURSDAY
PROVIDING QUIET WEATHER. LOOK FOR MOSTLY SUNNY SKIES ON THURSDAY
WITH HIGHS IN THE UPPER 20S TO LOWER 30S. SURFACE HIGH PRESSURE IS
EXPECTED TO SLIDE EAST OF THE AREA ON FRIDAY AS A POTENT TROUGH
DIVES INTO THE SOUTHWEST CONUS. MEANWHILE LOW PRESSURE DEVELOPS
OVER EASTERN COLORADO AS A WARM FRONT LIFTS NORTH OUT OF THE
CENTRAL PLAINS. TWO MAIN FEATURES TO WATCH CLOSELY ON FRIDAY...A
NORTHERN STREAM TROUGH DIVING SOUTH OUT OF CENTRAL SASKATCHEWAN
AND THE SOUTHWEST LOW LIFTING NORTHEAST TOWARD THE REGION. THE
WARM FRONT LOOKS TO LIFT NORTH INTO SOUTHERN MINNESOTA/SOUTHERN
WISCONSIN FRIDAY NIGHT INTO SATURDAY MORNING THEN LIFTING NORTH
THROUGH THE DAY ON SATURDAY. THE NORTHERN STREAM WAVE AND ENERGY
EJECTING OUT OF THE SOUTHWEST WILL INTERACT WITH THE FRONT
BRINGING PRECIPITATION TO THE AREA. WARM AIR ALOFT WILL SURGE INTO
THE UPPER MISSISSIPPI RIVER VALLEY FRIDAY NIGHT LEADING TO A MIX
OF PRECIPITATION TYPES. A MIX OF FREEZING RAIN...SLEET AND SNOW IS
EXPECTED FRIDAY EVENING INTO EARLY SATURDAY MORNING SWITCHING OVER
TO MAINLY RAIN DURING THE DAY ON SATURDAY. SOME ICE ACCUMULATION
IS POSSIBLE FRIDAY NIGHT INTO SATURDAY MORNING. A MOISTURE RICH
AIRMASS MOVES INTO THE AREA DURING THE DAY ON SATURDAY WITH
PRECIPITABLE WATER VALUES APPROACHING 270 PERCENT OF NORMAL.
ALSO...TEMPERATURES ARE EXPECTED TO WARM INTO THE UPPER 30S TO
LOWER 40S. 925/850 MB MOISTURE TRANSPORT FOCUSES INTO SOUTHERN
WISCONSIN AND FAR NORTHEAST IOWA SATURDAY INTO SATURDAY NIGHT.
PERIODS OF MODERATE TO HEAVY RAINFALL LOOK POSSIBLE SATURDAY INTO
SATURDAY NIGHT LEADING TO LOCALIZED FLOODING AND ICE JAMS ON AREA
RIVERS. FORECAST MODELS ARE JUST STARTING TO COME INTO AGREEMENT
ON THIS WARMER AND WET SOLUTION SO WILL HAVE TO KEEP A CLOSE WATCH
ON THE NEXT FEW RUNS.
.LONG TERM...SATURDAY THROUGH TUESDAY
328 AM CST WED MAR 6 2013
06.00 MEDIUM RANGE MODELS ARE IN REASONABLE AGREEMENT SATURDAY INTO
SATURDAY NIGHT BUT THEN START TO DIVERGE SUNDAY INTO EARLY MONDAY.
THE ECMWF SHIFTS THE BOUNDARY SOUTHEAST AND EAST OF THE AREA AS AN
UPPER LOW WRAPS UP OVER THE OHIO RIVER VALLEY. THE GFS LEANS TOWARD
THIS SOLUTION BUT IT IS FASTER THAN THE ECMWF...TAKING THE LOW
NORTH INTO THE EASTERN GREAT LAKES EARLY ON MONDAY. THE GEM OFFERS
A DIFFERENT SOLUTION WITH THE LOW TAKING SHAPE OVER NORTHERN
ILLINOIS WHICH WOULD BRING SIGNIFICANT SNOWFALL TO NORTHERN
WISCONSIN THROUGH SOUTHERN/CENTRAL MINNESOTA. HAVE LEANED TOWARD A
MODEL CONSENSUS BLEND APPROACH MONDAY INTO TUESDAY WITH CHANCES
FOR SNOW MONDAY INTO MONDAY NIGHT ACROSS MUCH OF THE AREA. SNOW
CHANCES WILL CONTINUE ACROSS NORTH CENTRAL WISCONSIN ON TUESDAY AS
SHORTWAVE MOVES ACROSS NORTHERN WISCONSIN. PLAN ON TEMPERATURES
COOLING SLIGHTLY EARLY NEXT WEEK WITH HIGHS FALLING INTO THE 30S
AND LOWS IN THE TEENS TO LOWER 20S.
&&
.AVIATION...THROUGH 18Z THURSDAY
1212 PM CST WED MAR 6 2013
FORECAST IS OF LOWER CONFIDENCE...ESPECIALLY FURTHER WEST AT KRST.
SATELLITE IMAGERY INDICATING A VERY EXPANSIVE MVFR CLOUD DECK
ACROSS THE REGION WITH SOME OLES OPENING UP INTO MVFR SCT/BKN
CONDITIONS /THUS THE TEMPO IN THE TAFS/. THE CLOUD LAYER IS VERY THIN
PER SATELLITE IMAGERY AS RIVERS ARE VISIBLE THROUGH IT. ANOTHER
SOMEWHAT DRYING PUSH OF AIR IS COMING IN FROM THE NORTH ASSOCIATED
WITH A WEATHER SYSTEM TRAVELING ACROSS CANADA. THIS LOOKS TO
POSSIBLY PROVIDE AN INFLUENCE OF CLOUD DIMINISHMENT BY EVENING AND
AFTER FROM THE NORTH.
HOWEVER...THE LOW LEVEL MOISTURE IS SITUATED WITHIN THE SURFACE
RIDGE WITH LIGHT WIND FLOW OVER MN/DAKOTAS. THIS SURFACE RIDGING
WILL SHIFT EAST AND BE LOCATED OVER THE MISS RIVER /KLSE/ BY
MORNING. THIS MORNING...WEST OF THE RIDGE AXIS...LIFR CONDITIONS
OCCURRED AND FG/CIGS IN THE LIFR RANGE. EXTRAPOLATING THIS TO THU
MORNING...THIS LIFR SYNOPTIC AREA WOULD BE OVER MN WITH KRST ON THE
EASTERN EDGE. SHORT RANGE MODEL ENSEMBLES /SREF/ INDICATE A HIGHER
PROBABILITY OF IFR ALONG AND WEST OF I-35...BUT VERY CLOSE TO
KRST.
THIS AFTERNOON...MARCH SUN ANGLES WILL WORK ON THINNING THE CLOUDS
AND EXPANDING THE PATCHES OF SCT/BKN OPENING UP. PREVIOUS FORECAST
HAD SCT CLOUDS BY LATE AFTERNOON...AND THEN MVFR BR FORMING.
ALTHOUGH CLOUDS ARE STILL WIDESPREAD AT 18Z...HAVE STAYED THE COURSE
ON CLEARING BY LATE AFTERNOON. BUT CONFIDENCE IS VERY LOW AND MVFR
CIGS COULD VERY WELL BE IN PLACE OVERNIGHT. IF THIS OCCURS...WOULD
THINK KRST COULD LOWER TO IFR CIGS BY MORNING. KLSE SHOULD REMAIN
MVFR. OVERALL...THIS FORECAST IS THE MOST OPTIMISTIC VERSION AT
THIS TIME AND FORECAST CHANGES WOULD PROBABLY BE TOWARD WORSENING
THE CIG/VSBYS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
328 AM CST WED MAR 6 2013
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...WETENKAMP
LONG TERM...WETENKAMP
AVIATION...BAUMGARDT
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
513 AM CST WED MAR 6 2013
.SHORT TERM...TO0DAY THROUGH FRIDAY
328 AM CST WED MAR 6 2013
FORECAST CONCERNS ARE ON FOG/FREEZING FOG POTENTIAL TONIGHT INTO
THURSDAY MORNING AND TEMPERATURES THROUGH FRIDAY. FOCUS THEN QUICKLY
TURNS TO PRECIPITATION TYPE CONCERNS THIS WEEKEND AND THE POTENTIAL
FOR MODERATE TO HEAVY RAINFALL ACROSS PARTS OF THE AREA.
LATEST WATER VAPOR IMAGERY AND 500 MB RAP ANALYSIS SHOWED LOW
PRESSURE OVER THE CENTRAL APPALACHIANS. A TROUGH WAS NOTED ALONG
THE MINNESOTA/ONTARIO BORDER. AN UPPER RIDGE WAS BUILDING ACROSS
THE WESTERN CONUS WITH A TROUGH MOVING ONTO THE WEST COAST. SURFACE
OBSERVATIONS INDICATED A RIDGE OF HIGH PRESSURE EXTENDING FROM THE
THE DAKOTAS SOUTH THROUGH THE SOUTHERN PLAINS. A SURFACE LOW WAS
NOTED OVER VIRGINIA WITH AN INVERTED TROUGH EXTENDING NORTHWEST
INTO FAR SOUTHEAST WISCONSIN.
THE TROUGH ALONG THE MINNESOTA/ONTARIO BORDER WILL PROGRESS EAST
TODAY ACROSS LAKE SUPERIOR AS THE SURFACE RIDGE EDGES EAST INTO
THE UPPER MISSISSIPPI RIVER VALLEY. THE MAIN FORECAST CHALLENGE
TODAY WILL BE CLOUD COVER. THERE ARE CURRENTLY PLENTY OF HOLES IN
THE STRATUS LAYER OVER EASTERN MINNESOTA INTO SOUTHWEST WISCONSIN.
FORECAST SOUNDINGS SHOW LOW LEVEL CLOUDS LINGERING THROUGH THE
MORNING HOURS BEFORE FINALLY CLEARING LATE THIS AFTERNOON. THE
FORECAST MODELS HAVE BEEN STRUGGLING WITH DEWPOINTS LATELY SO NOT
SOLD ON THE CLOUDS HOLDING ON AS LONG AS THE MODELS SUGGEST.
DECIDED TO GO WITH HIGHER CLOUD COVER THIS MORNING OVER THE
PREVIOUS FORECAST...WITH CLEARING OCCURRING FROM WEST TO EAST
DURING THE MID TO LATE AFTERNOON HOURS. THE NEXT CONCERN IS THE
POTENTIAL FOR FOG/FREEZING FOG TONIGHT. FOG WOULD BE MORE
FAVORABLE IF THE CLOUDS HOLD ON TODAY. SREF GUIDANCE AND FORECAST
SOUNDINGS CONTINUE TO SUGGEST FOG DEVELOPMENT TONIGHT. LOOKING
BACK TO THE WEST...UNDER THE SURFACE RIDGE...FOG HAS DEVELOPED.
THE SREF PROBABILITIES ARE CAPTURING THIS SO FEEL THEY ARE DOING A
DECENT JOB ON CAPTURING THE FOG. WILL MAINTAIN AREAS OF FOG IN THE
FORECAST OVERNIGHT INTO THURSDAY MORNING. VISIBILITIES COULD BE
REDUCED TO LESS THAN 1/2 MILE. ALSO...THE FOG COULD FREEZE TO
OBJECTS CREATING HOAR FROST. SOME LIGHT ICING MAY OCCUR ON AREA
ROADS...BUT THE RECENTLY APPLIED TREATMENT ON THE ROADS COULD
REALLY LIMIT ICING POTENTIAL. PLAN ON LOWS FALLING INTO THE SINGLE
DIGITS TONIGHT. FAVORED COLD SPOTS ACROSS CENTRAL INTO NORTH
CENTRAL WISCONSIN WILL SEE TEMPERATURES FALL INTO THE SINGLE DIGITS
BELOW ZERO.
HIGH PRESSURE WILL BE IN CONTROL ACROSS THE REGION ON THURSDAY
PROVIDING QUIET WEATHER. LOOK FOR MOSTLY SUNNY SKIES ON THURSDAY
WITH HIGHS IN THE UPPER 20S TO LOWER 30S. SURFACE HIGH PRESSURE IS
EXPECTED TO SLIDE EAST OF THE AREA ON FRIDAY AS A POTENT TROUGH
DIVES INTO THE SOUTHWEST CONUS. MEANWHILE LOW PRESSURE DEVELOPS
OVER EASTERN COLORADO AS A WARM FRONT LIFTS NORTH OUT OF THE
CENTRAL PLAINS. TWO MAIN FEATURES TO WATCH CLOSELY ON FRIDAY...A
NORTHERN STREAM TROUGH DIVING SOUTH OUT OF CENTRAL SASKATCHEWAN
AND THE SOUTHWEST LOW LIFTING NORTHEAST TOWARD THE REGION. THE
WARM FRONT LOOKS TO LIFT NORTH INTO SOUTHERN MINNESOTA/SOUTHERN
WISCONSIN FRIDAY NIGHT INTO SATURDAY MORNING THEN LIFTING NORTH
THROUGH THE DAY ON SATURDAY. THE NORTHERN STREAM WAVE AND ENERGY
EJECTING OUT OF THE SOUTHWEST WILL INTERACT WITH THE FRONT
BRINGING PRECIPITATION TO THE AREA. WARM AIR ALOFT WILL SURGE INTO
THE UPPER MISSISSIPPI RIVER VALLEY FRIDAY NIGHT LEADING TO A MIX
OF PRECIPITATION TYPES. A MIX OF FREEZING RAIN...SLEET AND SNOW IS
EXPECTED FRIDAY EVENING INTO EARLY SATURDAY MORNING SWITCHING OVER
TO MAINLY RAIN DURING THE DAY ON SATURDAY. SOME ICE ACCUMULATION
IS POSSIBLE FRIDAY NIGHT INTO SATURDAY MORNING. A MOISTURE RICH
AIRMASS MOVES INTO THE AREA DURING THE DAY ON SATURDAY WITH
PRECIPITABLE WATER VALUES APPROACHING 270 PERCENT OF NORMAL.
ALSO...TEMPERATURES ARE EXPECTED TO WARM INTO THE UPPER 30S TO
LOWER 40S. 925/850 MB MOISTURE TRANSPORT FOCUSES INTO SOUTHERN
WISCONSIN AND FAR NORTHEAST IOWA SATURDAY INTO SATURDAY NIGHT.
PERIODS OF MODERATE TO HEAVY RAINFALL LOOK POSSIBLE SATURDAY INTO
SATURDAY NIGHT LEADING TO LOCALIZED FLOODING AND ICE JAMS ON AREA
RIVERS. FORECAST MODELS ARE JUST STARTING TO COME INTO AGREEMENT
ON THIS WARMER AND WET SOLUTION SO WILL HAVE TO KEEP A CLOSE WATCH
ON THE NEXT FEW RUNS.
.LONG TERM...SATURDAY THROUGH TUESDAY
328 AM CST WED MAR 6 2013
06.00 MEDIUM RANGE MODELS ARE IN REASONABLE AGREEMENT SATURDAY INTO
SATURDAY NIGHT BUT THEN START TO DIVERGE SUNDAY INTO EARLY MONDAY.
THE ECMWF SHIFTS THE BOUNDARY SOUTHEAST AND EAST OF THE AREA AS AN
UPPER LOW WRAPS UP OVER THE OHIO RIVER VALLEY. THE GFS LEANS TOWARD
THIS SOLUTION BUT IT IS FASTER THAN THE ECMWF...TAKING THE LOW
NORTH INTO THE EASTERN GREAT LAKES EARLY ON MONDAY. THE GEM OFFERS
A DIFFERENT SOLUTION WITH THE LOW TAKING SHAPE OVER NORTHERN
ILLINOIS WHICH WOULD BRING SIGNIFICANT SNOWFALL TO NORTHERN
WISCONSIN THROUGH SOUTHERN/CENTRAL MINNESOTA. HAVE LEANED TOWARD A
MODEL CONSENSUS BLEND APPROACH MONDAY INTO TUESDAY WITH CHANCES
FOR SNOW MONDAY INTO MONDAY NIGHT ACROSS MUCH OF THE AREA. SNOW
CHANCES WILL CONTINUE ACROSS NORTH CENTRAL WISCONSIN ON TUESDAY AS
SHORTWAVE MOVES ACROSS NORTHERN WISCONSIN. PLAN ON TEMPERATURES
COOLING SLIGHTLY EARLY NEXT WEEK WITH HIGHS FALLING INTO THE 30S
AND LOWS IN THE TEENS TO LOWER 20S.
&&
.AVIATION...TODAY AND TONIGHT
513 AM CST WED MAR 6 2013
THE MAIN AVIATION CONCERNS ARE WHEN WILL THE MVFR STRATUS CLEAR
OUT AND POTENTIAL FOR FOG TONIGHT.
MVFR STRATUS ENCOMPASSES BOTH TAF SITES EARLY THIS MORNING...
THOUGH THERE ARE SOME POCKETS OF CLEAR SKIES ACROSS CENTRAL AND
EASTERN MINNESOTA. ANTICIPATING THAT THE COMBINATION OF SUNSHINE
AND HIGH PRESSURE BUILDING IN FROM THE PLAINS WILL SLOWLY BUT
SURELY BREAK UP THE STRATUS. THE POCKETS OF CLEAR SKIES...IF THEY
CAN HOLD TOGETHER UNTIL THE SUN COMES UP...WILL HELP AS WELL TO
MIX OUT THE STRATUS. KEPT THE PREVIOUS FORECAST IDEA OF A LATE
SCATTERING OUT TREND...BETWEEN 23-00Z. PLENTY OF UNCERTAINTY
EXISTS ON THIS...HOWEVER...AND IT COULD CLEAR EARLIER OR LATER. IT
DOES APPEAR THAT EVEN IN THE PESSIMISTIC CLEARING SCENARIO...THAT
BY 06Z BOTH TAF SITES WOULD BE CLEARED OUT. WITH LIGHT WINDS...THE
RIDGE AXIS IN PLACE AND LINGERING LOW LEVEL MOISTURE...CONCERN
THEN SHIFTS TO FOG. CERTAINLY POTENTIAL FOR DENSE FOG
FORMATION...ESPECIALLY IF THE LATE IN THE DAY CLEARING OCCURS AS
FORECAST. FOR NOW INCLUDED MVFR BR AT BOTH SITES...BUT AGAIN THIS
COULD END UP LOWER.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
328 AM CST WED MAR 6 2013
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...WETENKAMP
LONG TERM...WETENKAMP
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
328 AM CST WED MAR 6 2013
.SHORT TERM...TO0DAY THROUGH FRIDAY
328 AM CST WED MAR 6 2013
FORECAST CONCERNS ARE ON FOG/FREEZING FOG POTENTIAL TONIGHT INTO
THURSDAY MORNING AND TEMPERATURES THROUGH FRIDAY. FOCUS THEN QUICKLY
TURNS TO PRECIPITATION TYPE CONCERNS THIS WEEKEND AND THE POTENTIAL
FOR MODERATE TO HEAVY RAINFALL ACROSS PARTS OF THE AREA.
LATEST WATER VAPOR IMAGERY AND 500 MB RAP ANALYSIS SHOWED LOW
PRESSURE OVER THE CENTRAL APPALACHIANS. A TROUGH WAS NOTED ALONG
THE MINNESOTA/ONTARIO BORDER. AN UPPER RIDGE WAS BUILDING ACROSS
THE WESTERN CONUS WITH A TROUGH MOVING ONTO THE WEST COAST. SURFACE
OBSERVATIONS INDICATED A RIDGE OF HIGH PRESSURE EXTENDING FROM THE
THE DAKOTAS SOUTH THROUGH THE SOUTHERN PLAINS. A SURFACE LOW WAS
NOTED OVER VIRGINIA WITH AN INVERTED TROUGH EXTENDING NORTHWEST
INTO FAR SOUTHEAST WISCONSIN.
THE TROUGH ALONG THE MINNESOTA/ONTARIO BORDER WILL PROGRESS EAST
TODAY ACROSS LAKE SUPERIOR AS THE SURFACE RIDGE EDGES EAST INTO
THE UPPER MISSISSIPPI RIVER VALLEY. THE MAIN FORECAST CHALLENGE
TODAY WILL BE CLOUD COVER. THERE ARE CURRENTLY PLENTY OF HOLES IN
THE STRATUS LAYER OVER EASTERN MINNESOTA INTO SOUTHWEST WISCONSIN.
FORECAST SOUNDINGS SHOW LOW LEVEL CLOUDS LINGERING THROUGH THE
MORNING HOURS BEFORE FINALLY CLEARING LATE THIS AFTERNOON. THE
FORECAST MODELS HAVE BEEN STRUGGLING WITH DEWPOINTS LATELY SO NOT
SOLD ON THE CLOUDS HOLDING ON AS LONG AS THE MODELS SUGGEST.
DECIDED TO GO WITH HIGHER CLOUD COVER THIS MORNING OVER THE
PREVIOUS FORECAST...WITH CLEARING OCCURRING FROM WEST TO EAST
DURING THE MID TO LATE AFTERNOON HOURS. THE NEXT CONCERN IS THE
POTENTIAL FOR FOG/FREEZING FOG TONIGHT. FOG WOULD BE MORE
FAVORABLE IF THE CLOUDS HOLD ON TODAY. SREF GUIDANCE AND FORECAST
SOUNDINGS CONTINUE TO SUGGEST FOG DEVELOPMENT TONIGHT. LOOKING
BACK TO THE WEST...UNDER THE SURFACE RIDGE...FOG HAS DEVELOPED.
THE SREF PROBABILITIES ARE CAPTURING THIS SO FEEL THEY ARE DOING A
DECENT JOB ON CAPTURING THE FOG. WILL MAINTAIN AREAS OF FOG IN THE
FORECAST OVERNIGHT INTO THURSDAY MORNING. VISIBILITIES COULD BE
REDUCED TO LESS THAN 1/2 MILE. ALSO...THE FOG COULD FREEZE TO
OBJECTS CREATING HOAR FROST. SOME LIGHT ICING MAY OCCUR ON AREA
ROADS...BUT THE RECENTLY APPLIED TREATMENT ON THE ROADS COULD
REALLY LIMIT ICING POTENTIAL. PLAN ON LOWS FALLING INTO THE SINGLE
DIGITS TONIGHT. FAVORED COLD SPOTS ACROSS CENTRAL INTO NORTH
CENTRAL WISCONSIN WILL SEE TEMPERATURES FALL INTO THE SINGLE DIGITS
BELOW ZERO.
HIGH PRESSURE WILL BE IN CONTROL ACROSS THE REGION ON THURSDAY
PROVIDING QUIET WEATHER. LOOK FOR MOSTLY SUNNY SKIES ON THURSDAY
WITH HIGHS IN THE UPPER 20S TO LOWER 30S. SURFACE HIGH PRESSURE IS
EXPECTED TO SLIDE EAST OF THE AREA ON FRIDAY AS A POTENT TROUGH
DIVES INTO THE SOUTHWEST CONUS. MEANWHILE LOW PRESSURE DEVELOPS
OVER EASTERN COLORADO AS A WARM FRONT LIFTS NORTH OUT OF THE
CENTRAL PLAINS. TWO MAIN FEATURES TO WATCH CLOSELY ON FRIDAY...A
NORTHERN STREAM TROUGH DIVING SOUTH OUT OF CENTRAL SASKATCHEWAN
AND THE SOUTHWEST LOW LIFTING NORTHEAST TOWARD THE REGION. THE
WARM FRONT LOOKS TO LIFT NORTH INTO SOUTHERN MINNESOTA/SOUTHERN
WISCONSIN FRIDAY NIGHT INTO SATURDAY MORNING THEN LIFTING NORTH
THROUGH THE DAY ON SATURDAY. THE NORTHERN STREAM WAVE AND ENERGY
EJECTING OUT OF THE SOUTHWEST WILL INTERACT WITH THE FRONT
BRINGING PRECIPITATION TO THE AREA. WARM AIR ALOFT WILL SURGE INTO
THE UPPER MISSISSIPPI RIVER VALLEY FRIDAY NIGHT LEADING TO A MIX
OF PRECIPITATION TYPES. A MIX OF FREEZING RAIN...SLEET AND SNOW IS
EXPECTED FRIDAY EVENING INTO EARLY SATURDAY MORNING SWITCHING OVER
TO MAINLY RAIN DURING THE DAY ON SATURDAY. SOME ICE ACCUMULATION
IS POSSIBLE FRIDAY NIGHT INTO SATURDAY MORNING. A MOISTURE RICH
AIRMASS MOVES INTO THE AREA DURING THE DAY ON SATURDAY WITH
PRECIPITABLE WATER VALUES APPROACHING 270 PERCENT OF NORMAL.
ALSO...TEMPERATURES ARE EXPECTED TO WARM INTO THE UPPER 30S TO
LOWER 40S. 925/850 MB MOISTURE TRANSPORT FOCUSES INTO SOUTHERN
WISCONSIN AND FAR NORTHEAST IOWA SATURDAY INTO SATURDAY NIGHT.
PERIODS OF MODERATE TO HEAVY RAINFALL LOOK POSSIBLE SATURDAY INTO
SATURDAY NIGHT LEADING TO LOCALIZED FLOODING AND ICE JAMS ON AREA
RIVERS. FORECAST MODELS ARE JUST STARTING TO COME INTO AGREEMENT
ON THIS WARMER AND WET SOLUTION SO WILL HAVE TO KEEP A CLOSE WATCH
ON THE NEXT FEW RUNS.
.LONG TERM...SATURDAY THROUGH TUESDAY
328 AM CST WED MAR 6 2013
06.00 MEDIUM RANGE MODELS ARE IN REASONABLE AGREEMENT SATURDAY INTO
SATURDAY NIGHT BUT THEN START TO DIVERGE SUNDAY INTO EARLY MONDAY.
THE ECMWF SHIFTS THE BOUNDARY SOUTHEAST AND EAST OF THE AREA AS AN
UPPER LOW WRAPS UP OVER THE OHIO RIVER VALLEY. THE GFS LEANS TOWARD
THIS SOLUTION BUT IT IS FASTER THAN THE ECMWF...TAKING THE LOW
NORTH INTO THE EASTERN GREAT LAKES EARLY ON MONDAY. THE GEM OFFERS
A DIFFERENT SOLUTION WITH THE LOW TAKING SHAPE OVER NORTHERN
ILLINOIS WHICH WOULD BRING SIGNIFICANT SNOWFALL TO NORTHERN
WISCONSIN THROUGH SOUTHERN/CENTRAL MINNESOTA. HAVE LEANED TOWARD A
MODEL CONSENSUS BLEND APPROACH MONDAY INTO TUESDAY WITH CHANCES
FOR SNOW MONDAY INTO MONDAY NIGHT ACROSS MUCH OF THE AREA. SNOW
CHANCES WILL CONTINUE ACROSS NORTH CENTRAL WISCONSIN ON TUESDAY AS
SHORTWAVE MOVES ACROSS NORTHERN WISCONSIN. PLAN ON TEMPERATURES
COOLING SLIGHTLY EARLY NEXT WEEK WITH HIGHS FALLING INTO THE 30S
AND LOWS IN THE TEENS TO LOWER 20S.
&&
.AVIATION...THROUGH 06Z THURSDAY
1134 PM CST TUE MAR 5 2013
ALL OF THE SNOW HAS MOVED SOUTH OF THE TAF SITES WITH VFR
VISIBILITIES NOW PREVAILING. CEILING HEIGHTS HAVE BEEN ALL OVER
THE PLACE AS THE SURFACE TROUGH HAS WEAKENED BUT THE AREA STILL
REMAINS IN A LOW LEVEL CYCLONIC FLOW. THIS HAS ALLOWED POCKETS OF
VFR CEILING HEIGHTS OR EVEN CLEAR SKIES TO DEVELOP. THESE LAST FOR
A COUPLE OF HOURS BEFORE RETURNING TO MVFR. MEANWHILE...KRST SITS
IN AN IFR DECK AND IS THE ONLY SITE REPORTING ONE. SATELLITE SHOWS
THE CLOUDS EXTENDING WELL TO THE WEST UNTIL REACHING THE RIDGE
AXIS ACROSS THE DAKOTAS. MOST OF THE CEILINGS IN THIS CLOUD DECK
ARE MVFR SO WILL GO WITH THIS FOR THE MOST PART. THE 06.00Z NAM
CONTINUES TO KEEP THE LOW LEVEL RELATIVE HUMIDITY HIGH THROUGH
WEDNESDAY UNTIL THE RIDGE AXIS MOVES OVERHEAD DURING THE LATE
AFTERNOON OR EVENING. BASED ON THIS AND THE SATELLITE
TRENDS...WILL HOLD ONTO THE CLOUDS THROUGH WEDNESDAY AFTERNOON.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
328 AM CST WED MAR 6 2013
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...WETENKAMP
LONG TERM...WETENKAMP
AVIATION...04
AREA FORECAST DISCUSSION...UPDATED
NWS PITTSBURGH PA
1234 AM EST FRI MAR 8 2013
.SYNOPSIS...
COLD NORTHWEST FLOW WILL KEEP SCATTERED SNOW SHOWERS AND FLURRIES
IN THE REGION THROUGH THE MORNING. HIGH PRESSURE WILL BRING
CLEARING SKIES AND WARMER TEMPERATURES BY THIS WEEKEND.
&&
.NEAR TERM /THROUGH TODAY/...
LATEST RUC INDICATING UPPER LEVEL LOW A BIT FURTHER EAST AS IS ITS
ASSOCIATED SHORTWAVE. ENHANCED SAT SHOWING TWO SEPARATE BANDS OF
LIGHT SNOW SHOWERS/FLURRIES. WESTERN BAND OVER MY OHIO/N WV
COUNTIES IS QUICKLY DISSIPATING AND THE BAND TO THE NORTHEAST IS
DOING THE SAME. MOST OF THE SNOW FALLING TO THE WEST WAS FLURRIES
WHILE THE SNOW TO THE NORTHEAST...WAS SLIGHTLY MORE SUBSTANTIAL.
FORECAST SOUNDINGS ARE SHOWING THE INVERSIONS DROPPING QUICKLY AND
THE OVERALL ATMOSPHERE DRYING OUT. FLOW ALOFT WILL VEER TO THE
NORTH AS THE NIGHT PROGRESSES WHICH WILL LIMIT THE INFLUENCES FROM
THE LAKES AND UP-SLOPING. FOR THE OVERNIGHT...WILL KEEP POPS TO
THE NORTHEAST AND RIDGES...AS THESE AREAS WILL BE IN CLOSER
PROXIMITY TO THE STRONG SHORTWAVE. FOR THE REST OF THE AREA WILL
JUST MENTION FLURRIES.
BY 12Z...UPPER LEVEL LOW WILL BE NEAR THE CHESAPEAKE BAY AND THE
STRONG SHORTWAVE WILL BE RIGHT ON ITS HEELS. EXPECT ANY LINGERING
SNOW SHOWERS/FLURRIES TO DISSIPATE DURING THE POST DAWN
MORNING...WITH THE RIDGES EXPIRING LAST. OVERALL ATMOSPHERIC
MOISTURE WILL DECREASE THIS AFTERNOON AND WAA WILL COMMENCE.
INTERESTINGLY ENOUGH...THE WARMER AIR WILL MOVE DOWN FROM THE
NORTHEAST ON THE BACK SIDE OF THE EXITING 50H LOW. THIS WARMER AIR
WILL QUICKLY OVERTAKE AND ELIMINATE THE COLD POOL ALOFT. EXPECT TO
SEE A DECREASE IN CLOUD COVER THIS AFTERNOON...HOWEVER TEMPS WILL
REMAIN BELOW NORMAL.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY/...
DRY AND COLD FRIDAY NIGHT UNDER HIGH PRESSURE. SATURDAY WILL WARM
DRAMATICALLY UNDER WARM ADVECTION AS SOUTHWEST FLOW AT 850MB
BRINGS TEMPERATURES OVER +5C...AND WITH LOTS OF SUNSHINE
TEMPERATURES WILL SURGE INTO THE UPPER 40S NORTH AND MID 50S
SOUTH. MILD SATURDAY NIGHT AND WARMER SUNDAY IN STRENGTHENING
SOUTHWEST FLOW AHEAD OF AN APPROACHING COLD FRONT. 60 DEGREES MAY
BE REACHABLE SUNDAY AFTERNOON IN PITTSBURGH BUT INCREASE IN CLOUDS
MAY TEMPER WARMING. HAVE UNDERCUT GUIDANCE BUT STILL WELL ABOVE
AVERAGE.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
MODELS ARE IN GENERAL WITH SOLNS FEATURING THE APPRCH OF AN
AMPLIFIED LOW PRES TROF/ASSOCIATED CDFNT LATE SUNDAY. HAVE THUS
PERSISTED WITH POP ESCALATION FM CHC TO LIKELY NMBRS ON SUNDAY NGT
AND MONDAY...AS WELL AS WITH EXPECTATIONS OF LOW PRES FORMING ON THE
FRONTAL BOUNDARY AND LIKELY STALLING DECISIVE PASSAGE UNTIL TUESDAY.
THEREAFTER...DIVERGENT SOLNS ARE EXHIBITED IN THE ECMWF AND GFS
COMPARISON WITH THE ECMWF INDICATING ANOTHER AMPLIFIED ERN NORTH
AMERICAN TROF...WHILE GFS FLATTENS THE FLOW. PREVIOUS FORECAST FOR
MID TO LATE WEEK FAVORS THE COOLER ECMWF...AND LACK OF CONFIDENCE
PRECLUDES ANY MAJOR ALTERATIONS TO THAT TIME FRAME.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
A WEAK DISTURBANCE IN THE FLOW ALOFT ROTATING AROUND COASTAL
SYSTEM WILL CONTINUE TO HELP STRATO-CU HOLD IN OVERNIGHT. BEST
SUPPORT FOR -SHSN WANING AS SUGGESTED BY HRRR. BACK EDGE OF BEST
LOW LEVEL SUPPORT PUSHING ACROSS FORECAST AREA AT THIS TIME.
AFTERWARDS WITH -8C AT 850 MB AND NW FLOW WILL CARRY -SHSN WITH
5-6SM VSBY EARLY IN THE PERIOD AND THEN DROP OUT. WILL KEEP LOWER
STRATO-CU AROUND OVERNIGHT AND THEN RAISE CEILINGS IN MORNING WITH
STILL BKN035. WILL SCATTERED OUT FROM SW TO NE BY FRIDAY AFTERNOON
AND GO SKC FRIDAY NIGHT. NORTHWEST WINDS 5-10 KTS TONIGHT AND
INCREASE THEM TO NORTHWEST 11-13KT G17KT ON FRIDAY WITH CONTINUED
FAIRLY TIGHT PRESSURE GRADIENT DUE TO COASTAL SYSTEM`S SLOWNESS TO
PULL AWAY.
.OUTLOOK.../FRIDAY NIGHT THROUGH TUESDAY/...
VFR CONDITIONS FRIDAY NIGHT THROUGH MOST OF SUNDAY AS HIGH
PRESSURE DOMINANTS THE FORECAST AREA. NEXT WEATHER SYSTEM APPROACHES
BY LATE SUNDAY WITH SHOWERS AND RESTRICTIONS POSSIBLE THROUGH
EARLY TUESDAY. CLEARING EXPECTED LATER ON TUESDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
244 AM CST FRI MAR 8 2013
.DISCUSSION...
SIMILAR SCENARIO TONIGHT AS THE FORECAST IS HIGHLY VARIABLE BASED
ON THERMAL PROFILES BELOW 70H.
THE MODELS HAVE BEEN CONSISTENT IN TERMS OF THE EC THE
COOLEST...AND THE NAM/WRF THE WARMEST. THE GEM/GFS ARE SOMEWHAT
INBETWEEN. ALTHOUGH THE NAM/WRF REMAINS THE WARMEST AND KEEPS
MOST OF THE PRECIPITATION IN THE FORM OF RAIN...THE GFS HAS COME A
BIT CLOSER TO THE EC WHICH MEANS MORE OF A SLEET/SNOW SCENARIO FOR
AREAS ACROSS THE N/NW FA. DUE TO THE VARIABILITY OF THE THERMAL
PROFILES...WILL CONTINUE THE WINTER STORM WATCH IN THE SAME AREAS
AS BEFORE.
IT STILL LOOKS ALMOST CERTAIN THAT THE FAR NW FA WILL SEE THE BULK
OF THE ICE/SNOW BEFORE TAPERING OFF SATURDAY EVENING. ELSEWHERE IS
HIGHLY DEPENDENT ON SFC TEMPS AND WHETHER THE WARMER 85H TEMPS
MATERIALIZE. BEST TIME PERIOD FOR FREEZING RAIN WILL OCCUR TOWARD
MIDNIGHT TONIGHT...AS THE COMBINATION OF COOLER SFC TEMPS DURING
THE NIGHT...AND EVAPORATIVE COOLING EFFECTS DURING THE ONSET OF
THE PRECIPITATION. ONCE HEAVIER PRECIPITATION DEVELOPS...THE
SCENARIO GETS TRICKY WITH THE POSSIBILITY OF CONVECTION AND LATENT
HEAT EFFECTS WITH THE LIQUID PRECIPITATION. SNOW COVER IS ANOTHER
ELEMENT WHICH COULD LEAD TO MORE FREEZING RAIN ON SURFACES...OTHER
THAN STREETS/ROADWAYS WHICH WOULD BE MORE WET DUE TO CHEMICALS AND
OTHER PROCESSES. THE CONVECTIVE ELEMENT IS ALSO PROBLEMATIC WHICH
CAN LEAD TO BRIEF PERIODS OF SLEET OR SNOW DEPENDING UPON THE
PRECIPITATION INTENSITY.
ANOTHER CONCERN IS POTENTIAL AREAL FLOODING AS THE PRECIPITABLE
WATER VALUES ARE NEAR 0.80 INCHES. THIS IS ROUGHLY 2 STANDARD
DEVIATIONS ABOVE NORMAL FOR EARLY MARCH. THE CURRENT ESF DOES
EXPLAIN THIS SCENARIO AND THE BEST LOCATION FOR HEAVY RAINFALL
RATES...AND THE RAPID SNOWFALL MELT WOULD BE ACROSS SOUTH CENTRAL
MINNESOTA. DUE TO MORE CONSISTENCY OF THE NORTHERN AND SOUTHERN
JET STREAMS NOT PHASING WITH THE UPCOMING WEEKEND SYSTEM...WHICH
WAS A POSSIBILITY EARLIER...THE SCENARIO OF A BAND OF HEAVY
SNOWFALL ACROSS THE SE FA IS LESS LIKELY. THE BETTER POSSIBILITIES
OF HEAVIER SNOWFALL RATES WILL OCCUR ACROSS IA/WI ON SUNDAY.
NO OTHER CHGS IN THE FORECAST BEYOND THIS WEEKEND AS THE PATTERN
IS LESS ACTIVE...BUT SEASONABLY COOL FOR MID MARCH. DO NOT EXPECT
ANY RAPID WARM-UP UNTIL THE SNOW COVER IS GONE AND THE UPPER LEVEL
FLOW BECOMES MORE SW. ..JLT..
&&
.AVIATION.../06Z TAF ISSUANCE/
FIRST CHANGE MADE TO 6Z TAFS WAS TO REMOVE RETURN OF MVFR CIGS
THIS EVENING. RAP AND HRRR HAVE BEEN CONSISTENT ON TAKING MVFR
CIGS OVER ERN NODAK DUE EAST ACROSS NRN MN...WILL BE A CLOSE CALL
FOR AXN/STC...BUT CONFIDENCE IS HIGH THAT THIS STRATUS WILL REMAIN
NORTH OF OTHER TERMINALS. INCREASING MOISTURE ON SE SFC WINDS HAS
RESULTED IN BLOSSOMING OF MVFR BR ACROSS NRN IA/SRN MN...AND DO
EXPECT SIMILAR VSBY TO IMPACT RWF...THOUGH EXPECT INCREASED WINDS
TONIGHT TO KEEP VSBY NO WORSE THAN IFR. AFTER THAT...LOTS OF
ACTION JAMMED INTO THE END OF THE TAF PERIOD AS A WALL OF CLOUDS
AND PRECIP COMES NE INTO THE AREA ON A STRONG LLJ. GFS LOOKED TO
ROBUST WITH MOISTURE OUT AHEAD OF THIS SYSTEM...SO FAVORED END OF
TAFS HEAVILY TOWARD A NAM/SREF TIMING. AS FOR P-TYPE...TEMPS LOOK
TO BE BELOW FREEZING AT STC/AXN...SO WENT WITH FZRA FOR THEM.
RWF/MSP WILL LIKELY BE NEAR OR JUST ABOVE FREEZING. BASED ON NAM
AND SREF P-TYPE PLUMES...EXPECT PREDOMINATE TYPE TO BE RA AT BOTH
LOCATIONS...THOUGH LEFT A PROB30 FZRA IN AT MSP TO ACCOUNT FOR THE
UNCERTAINTY.
KMSP...HIGH CONFIDENCE IN FORECAST PARAMETERS THROUGH 00Z. ABOUT
THE ONLY THING THAT MAY DIFFER FROM CURRENT TAF IS THE POSSIBILITY
FOR SOME MVFR BR/HZ IN THE MORNING. AT THE END OF THE
TAF...SOUNDINGS SAY WHATEVER FALLS AT THE FIELD WILL BE
LIQUID...WITH THE KEY BEING SFC TEMP. PROBABILITIES FAVOR TEMPS
BEING WARM ENOUGH FOR RA...BUT EVEN SO...4 MEMBERS OF THE SREF DO
SHOW A FEW HOURS OF FZRA SAT MORNING...SO LEFT THE PROB30 GROUP
FOR -FZRA TO GO WITH THE PREVAILING -RA.
/OUTLOOK FOR KMSP/
SAT...IFR AND RAIN. LIFR AND -FZRA POSSIBLE IN THE MORNING. WINDS
E AT 10KTS.
SUN...MVFR OR LOWER WITH -SN POSSIBLE EARLY. WINDS N AT 15G25KTS.
MON...VFR. LIGHT NW WINDS BECOMING S IN THE AFTERNOON.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER STORM WATCH FROM THIS EVENING THROUGH SUNDAY MORNING FOR
BENTON-CHIPPEWA-DOUGLAS-KANABEC-KANDIYOHI-LAC QUI PARLE-
MCLEOD-MEEKER-MILLE LACS-MORRISON-POPE-REDWOOD-RENVILLE-
SHERBURNE-STEARNS-STEVENS-SWIFT-TODD-WRIGHT-YELLOW MEDICINE.
WI...NONE.
&&
$$
JLT/MPG
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1135 PM CST THU MAR 7 2013
.UPDATE...
06Z AVIATION DISCUSSION ADDED BELOW.
&&
.PREV DISCUSSION.../ISSUED 419 PM CST THU MAR 7 2013/
TONIGHT...THE MAIN FCST ISSUE OVERNIGHT WILL BE THE EXTENT OF
CLOUD COVER AND ITS EFFECTS ON TEMPS AND FOG POTENTIAL. HIGH
CLOUDS CURRENTLY STREAMING OVERHEAD...WITH A BANK OF STRATUS
LURKING ACROSS NORTH CENTRAL SD EXTENDING INTO ND. 1000-850MB RH
FROM THE NAM DEPICTS THE STRATUS PRETTY WELL...AND LEANED ON ITS
FCST PRETTY HEAVILY FOR CLOUD COVER TRENDS. THE HIGH CLOUDS SHOULD
PARTIALLY CLEAR OUT ACROSS W WI LATER TONIGHT LEADING TO POTENTIAL
PATCHY FOG DEVELOPMENT. ANY FOG SHOULD BE FAIRLY LOCALIZED AS
WINDS WILL BE STRONGER THAN LAST NIGHT KEEPING THE BL WELL-MIXED.
WITH A PERSISTENT SE WIND, CLOUD COVER...AND THE BEGINNINGS OF
WARM ADVECTION...LOW TEMPS WILL BE SUBSTANTIALLY WARMER THAN LAST
NIGHT (MID TEENS TO LOWER 20S).
FRIDAY THROUGH SUNDAY...HIGH PRES WILL SHIFT WELL E OF THE AREA
DURG THE DAY ON FRI WHILE A LONGWAVE RIDGE GLIDES OVER THE AREA.
THE COMBINATION OF BOTH FEATURES WILL ALLOW FOR STRONG WARMING
OVER THE AREA...INCLUDING HIGHS REACHING THE MIDDLE AND UPPER 30S
DESPITE AN INCREASE IN CLOUD COVER. THE MOST IMPORTANT ASPECT WILL
BE THE MELTING OF THE SNOWPACK...ALLOWING FOR SIGNIFICANT RUNOFF
AND MAKING FOR THE POTENTIAL OF REFREEZING FRIDAY NIGHT FOR
LOCATIONS THAT DROP BACK TO THE FREEZING MARK. AS FOR SENSIBLE WX
FRI NIGHT THRU SUN...THE LONGWAVE RIDGE AXIS WILL SHIFT TO THE E
FRI NIGHT WHILE A LARGE TROUGH DIGS INTO THE SOUTHWEST. AN AREA OF
LOW PRES DEVELOPING OVER THE CENTRAL ROCKIES WILL BECOME PICKED UP
BY THE LARGE TROUGH...NUDGING IT INTO THE CENTRAL PLAINS SAT THEN
INTO THE GREAT LAKES ON SUN. DEEP MOISTURE WILL STEADILY SPREAD
NE INTO THE REGION FRI EVE ALONG THE WMFNT OF THE ROCKIES LOW PRES
CENTER. SIGNIFICANT LIFT FROM NOT ONLY THE FNT BUT A MIDLVL SHTWV
TROUGH AXIS SWINGING THRU THE NRN PLAINS WILL AID IN PRECIP
SPREADING W TO E ACRS THE WFO MPX CWFA FRI NIGHT. COMPLICATING
MATTER IS THE DEPTH OF SHALLOW WARM AIR IN THE BLYR THAT WILL MESS
WITH THE P-TYPE FCST. BUFKIT SOUNDINGS AND SREF PROGS INDICATE A
MIX OF -FZRA/-SN FOR MUCH OF THE NIGHT CAN BE EXPECTED...
PARTICULARLY OVER WRN INTO CENTRAL MN. AS THE PRECIP SPREADS
FURTHER E...INTENSITY IS EXPECTED TO INCRS AS PWATS CLIMB TO ARND
1 INCH FRI NIGHT INTO MIDDAY SAT. HOWEVER...P-TYPE IS EXPECTED TO
MIX WITH AND CHANGE OVER TO RAIN FOR MUCH OF THE AREA AS TEMPS
RISE TO THE MID 30S ON SAT. THE CDFNT OF THIS SYSTEM WILL THEN
APPROACH LATE SAT NIGHT INTO EARLY SUN MRNG...FORCING THE CHANGE
OF THE P-TYPE FROM RAIN /OR POSSIBLY A SMALL WINDOW OF -FZRA/ OVER
TO -SN SAT NIGHT INTO SUN MRNG. WITH STILL DEEP MOISTURE IN
PLACE...SOME MINOR TO MODERATE SNOW ACCUMULATIONS APPEAR LIKELY.
THE SNOWFALL WILL THEN GRADUALLY TAPER OFF DURG THE DAY ON SUN
FROM W TO E AS TEMPERATURES ARE EXPECTED TO REMAIN NEAR TO BELOW
FREEZING LATE SAT NIGHT THRU SUN NIGHT. THERE IS STILL MUCH
UNCERTAINTY IN TEMPERATURE PROFILES ALONG WITH THE PLACEMENT OF
THE DEEPEST MOISTURE...BUT THERE IS ENOUGH MODEL AGREEMENT SUCH
THAT THE HEAVIEST ICING /BETWEEN A TENTH AND A QUARTER INCH/ ALONG
WITH THE HEAVIEST SNOWFALL /BETWEEN 3 AND 6 INCHES/ SUCH THAT
CONFIDENCE IS HIGH ENOUGH TO ISSUE A WINTER STORM WATCH FOR
PORTIONS OF WEST CENTRAL AND CENTRAL MINNESOTA STARTING FRIDAY
NIGHT. EVEN THOUGH THE WATCH IS IN PLACE...ADVISORY-LEVEL ICING
AND/OR SNOWFALL LOOKS POSSIBLE JUST EAST OF WHERE THE WATCH IS
CURRENTLY DELINEATED SO ADDITIONAL SUPPLEMENTAL PRODUCTS MAY BE
ISSUED DURING LATER PRODUCT PACKAGES TO ADDRESS THESE ISSUES. HIGH
PRESSURE THEN COMES IN SUNDAY EVENING AND SUNDAY NIGHT WHICH WILL
HELP CLEAR AWAY ANY REMAINING PRECIP...PRODUCE PARTIAL CLEARING
SKIES AND PROMOTE COLD AIR ADVECTION THAT WILL MAKE FOR LOW TEMPS
SUN NIGHT DROPPING BACK INTO THE SINGLE DIGITS TO MID TEENS.
MONDAY THROUGH WEDNESDAY...HIGH PRES LOOKS TO PREVAIL ON MON AS A
SHORTWAVE BUBBLE RIDGE LOOKS TO GLIDE ON THROUGH THE REGION.
HOWEVER...A PROGRESSIVE WNW-ESE FLOW WILL DEVELOP TUE AND WED THAT
WILL ALLOW A PAIR OF SHALLOW CLIPPER-TYPE LOW PRESSURE SYSTEMS TO
SHIFT ON THROUGH THE REGION. NEITHER LOOKS PARTICULARLY STRONG NOR
MOISTURE-LADEN SO HAVE KEPT ONLY SLGT-LOW CHC POPS IN PLACE.
TEMPERATURES WILL DROP BACK TO BELOW NORMAL LEVELS DURING THE
FIRST HALF OF NEXT WEEK.
&&
.AVIATION.../06Z TAF ISSUANCE/
FIRST CHANGE MADE TO 6Z TAFS WAS TO REMOVE RETURN OF MVFR CIGS
THIS EVENING. RAP AND HRRR HAVE BEEN CONSISTENT ON TAKING MVFR
CIGS OVER ERN NODAK DUE EAST ACROSS NRN MN...WILL BE A CLOSE CALL
FOR AXN/STC...BUT CONFIDENCE IS HIGH THAT THIS STRATUS WILL REMAIN
NORTH OF OTHER TERMINALS. INCREASING MOISTURE ON SE SFC WINDS HAS
RESULTED IN BLOSSOMING OF MVFR BR ACROSS NRN IA/SRN MN...AND DO
EXPECT SIMILAR VSBY TO IMPACT RWF...THOUGH EXPECT INCREASED WINDS
TONIGHT TO KEEP VSBY NO WORSE THAN IFR. AFTER THAT...LOTS OF
ACTION JAMMED INTO THE END OF THE TAF PERIOD AS A WALL OF CLOUDS
AND PRECIP COMES NE INTO THE AREA ON A STRONG LLJ. GFS LOOKED TO
ROBUST WITH MOISTURE OUT AHEAD OF THIS SYSTEM...SO FAVORED END OF
TAFS HEAVILY TOWARD A NAM/SREF TIMING. AS FOR P-TYPE...TEMPS LOOK
TO BE BELOW FREEZING AT STC/AXN...SO WENT WITH FZRA FOR THEM.
RWF/MSP WILL LIKELY BE NEAR OR JUST ABOVE FREEZING. BASED ON NAM
AND SREF P-TYPE PLUMES...EXPECT PREDOMINATE TYPE TO BE RA AT BOTH
LOCATIONS...THOUGH LEFT A PROB30 FZRA IN AT MSP TO ACCOUNT FOR THE
UNCERTAINTY.
KMSP...HIGH CONFIDENCE IN FORECAST PARAMETERS THROUGH 00Z. ABOUT
THE ONLY THING THAT MAY DIFFER FROM CURRENT TAF IS THE POSSIBILITY
FOR SOME MVFR BR/HZ IN THE MORNING. AT THE END OF THE
TAF...SOUNDINGS SAY WHATEVER FALLS AT THE FIELD WILL BE
LIQUID...WITH THE KEY BEING SFC TEMP. PROBABILITIES FAVOR TEMPS
BEING WARM ENOUGH FOR RA...BUT EVEN SO...4 MEMBERS OF THE SREF DO
SHOW A FEW HOURS OF FZRA SAT MORNING...SO LEFT THE PROB30 GROUP
FOR -FZRA TO GO WITH THE PREVAILING -RA.
/OUTLOOK FOR KMSP/
SAT...IFR AND RAIN. LIFR AND -FZRA POSSIBLE IN THE MORNING. WINDS
E AT 10KTS.
SUN...MVFR OR LOWER WITH -SN POSSIBLE EARLY. WINDS N AT 15G25KTS.
MON...VFR. LIGHT NW WINDS BECOMING S IN THE AFTERNOON.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER STORM WATCH FROM FRIDAY EVENING THROUGH SUNDAY MORNING
FOR BENTON-CHIPPEWA-DOUGLAS-KANABEC-KANDIYOHI-LAC QUI PARLE-
MCLEOD-MEEKER-MILLE LACS-MORRISON-POPE-REDWOOD-RENVILLE-
SHERBURNE-STEARNS-STEVENS-SWIFT-TODD-WRIGHT-YELLOW MEDICINE.
WI...NONE.
&&
$$
JPC/MPG
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1239 AM EST FRI MAR 8 2013
.SYNOPSIS...
COOL AND DRY CANADIAN HIGH PRESSURE WILL REMAIN OVER THE REGION
INTO THE WEEKEND. A COLD FRONT WILL MOVE ACROSS THE REGION LATE
MONDAY REACHING THE COAST BY TUESDAY. ANOTHER DRY HIGH WILL MOVE
INTO THE AREA FOR MID WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 1235 AM...WINDS HAVE REMAINED UP OUTSIDE OF THE MTNS AND GUSTY
OVER THE MTNS. EXPECT THE WINDS TO CONTINUE UNTIL NEAR DAYBREAK WHEN
THEY DIMINISH. LINGERING LOW CLOUDS WILL REMAIN NEAR THE TN BORDER
BUT BEGIN DISSIPATING FROM THE SW NEAR DAYBREAK.
AS OF 1035 PM EST THU...BLENDED IN SOME RUC13 WINDS WHICH HAS BUMPED
UP THE SPEEDS A LITTLE OVER THE NRN PART OF THE UPSTATE AND THE SRN
NC PIEDMONT. WINDS ARE RUNNING AROUND 10 KTS IN THESE AREAS ATTM.
OTHERWISE THE SKY GRIDS WERE AGAIN TWEAKED TO CAPTURE THE CURRENT
ORIENTATION OF THE STRATO-CU ALONG THE TN LINE. IT/S MADE SOME
PROGRESS UP THE FRENCH BROAD AND PIGEON RIVER VALLEYS...THOUGH I
DON/T SEE IT GETTING MUCH FURTHER SOUTH. TEMPERATURES WERE LOWERED
AGAIN OVER THE NRN NC FOOTHILLS.
AS OF 755 PM EST THU...ADDED A LITTLE MORE CLOUD COVER RIGHT ALONG
THE TN LINE. ALSO LOWERED HOURLY TEMPS A FEW DEGREES OVER THE NRN
MTNS AND NC FOOTHILLS WHERE TEMPS ARE RUNNING LOWER THAN PREDICTED.
THE REST OF THE GRIDS LOOK TO BE IN GOOD SHAPE.
AS OF 510 PM EST THU...UPDATED SKY GRIDS TO ACCOUNT FOR SHARP
CLEARING LINE ALONG THE TN LINE. UPSTREAM STRATUS HAS BEEN VERY
PERSISTENT AND I HAVE IT HOLDING ON RIGHT ALONG THE LINE FOR SEVERAL
MORE HOURS. THE OTHER 98 PERCENT OF THE FORECAST AREA WILL HAVE A
LOVELY EVENING. TEMPERATURES WERE ALSO ADJUSTED DOWN A FEW DEGREES
OVER THE CENTRAL AND NRN MTNS...MAINLY AS A RESULT OF SNOW COVER.
PREVIOUS DISCUSSION...
THE REGION WILL REMAIN UPSTREAM OF A LONG WAVE TROUGH OFF THE EAST
COAST...WITH HIGH AMPLITUDE RIDGING TO THE WEST THROUGH THE PERIOD.
THIS WILL SUPPORT A RIDGE OF SURFACE HIGH PRESSURE ACROSS THE
REGION. SOME DEGREE OF LOW LEVEL MOISTURE WILL CONTINUE TO SUPPORT
UPSLOPE STRATOCU ALONG THE IMMEDIATE TENN BORDER...AND THIS MAY EVEN
EXPAND A BIT TONIGHT. OTHER THAN THAT...FAIRLY GOOD RADIATIONAL
COOLING CONDITIONS ARE EXPECTED TONIGHT...WHICH SHOULD ALLOW MIN
TEMPS TO COOL TO ABOUT 10 DEGREES BELOW NORMAL.
FRIDAY...THE WESTERN ATLANTIC TROUGH RECEIVES SOME REINFORCEMENT...
AS A POTENT SHORT WAVE DIGS OFF THE MID-ATLANTIC COAST. THIS WILL
SUPPORT CONTINUED LOW THICKNESS VALUES ACROSS OUR AREA...AND MAX
TEMPS WILL BE ONLY MARGINALLY DIFFERENT THAN TODAY/S READINGS.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY/...
AS OF 145 PM THURSDAY...AN UPPER LEVEL RIDGE WILL DOMINATE THE
WEATHER THROUGH THE UPCOMING WEEKEND PROVIDING VERY PLEASANT AND DRY
WEATHER. THE RIDGE AXIS IS FORECAST TO MOVE EAST OF THE APPALACHIANS
BY 12Z SUNDAY. AT THE SFC...A NORTH TO SOUTH ORIENTED HIGH PRESSURE
SYSTEM WILL MOVE FROM THE MID WEST FRIDAY NIGHT...TO OFF THE EAST COAST
ON SUNDAY. THIS WILL RESULT IN MOSTLY CLEAR CONDITIONS THROUGH SAT
NIGHT. THE RETURN FLOW ON THE WESTERN PERIPHERY OF THE HIGH WILL
TRANSPORT INCREASING ATLANTIC MOISTURE INTO THE AREA BEGINNING SAT
NIGHT AND CONTINUING ON SUN. THEREFORE...EXPECT INCREASING AMOUNTS
OF CLOUDS FROM LATE SATURDAY NIGHT INTO SUNDAY.
RIDGING ALOFT AND WARMING LOW LEVEL THICKNESSES SHOULD RESULT IN
ABOVE NORMAL HIGHS BOTH SATURDAY AND SUNDAY. MAX TEMPS SHOULD REACH
THE MID 60S OUTSIDE THE MOUTNAINS...WITH EVEN LOW 60S MOUNTAIN
VALLEYS. GOOD RADIATIONAL COOLING FRI NIGHT WILL ALLOW MIN TEMPS TO
COOL AROUND 5 DEGREES BELOW NORMAL...BUT NEAR TO A LITTLE ABOVE
NORMAL TEMPS SHOULD OCCUR SAT NIGHT AS MOISTURE INCREASES.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 145 PM EST THURSDAY...07/12Z GFS AND 07/00Z ECM ARE IN FAIRLY
GOOD AGREEMENT IN REGARD TO THE PERTINENT WEATHER FEATURES THROUGH
THE MEDIUM RANGE. THE 07/12Z CANADIAN CAME IN AS AN OUTLIER AND WAS
DISREGARDED FOR THIS FORECAST. AN UPPER RIDGE WILL BE MOVING EAST OF
THE AREA AT THE BEGINNING OF THE PERIOD WITH A SHORT WAVE TROUGH
OVER THE MIDWEST. THE UPPER TROUGH IS FORECAST TO MOVE EAST AND
TRAVERSE THE REGION MONDAY NIGHT INTO TUE. THE TROUGH WILL DRIVE A
SURFACE COLD FRONT THROUGH THE AREA. MODEL TIMING FOR THE COLD
FRONTAL PASSAGE IS CONVERGING ON MON NIGHT INTO EARLY TUE. AS
SURFACE HIGH PRESSURE MOVES EAST OF THE AREA SUNDAY NIGHT AND
MON...THE RETURN FLOW WILL TAP INTO ATLANTIC/GULF MOISTURE OUT AHEAD
OF THE COLD FRONT. A FEW SHOWERS COULD DEVELOP OVER WESTERN UPSLOPE
AREAS BY EARLY MON. SHOWERS ARE THEN EXPECTED TO SLOWLY EVERSPREAD
MOST OF THE AREA ON MONDAY FROM WEST TO EAST. THE COLD FRONT WILL
CROSS THE AREA MONDAY NIGHT INTO EARLY TUE. MODERATE AMOUNTS OF
RAINFALL ARE EXPECTED ACROSS THE REGION...MOST LIKELY IN THE HALF
INCH TO INCH RANGE. WITH THE FRONTAL PASSAGE OCCURRING DURING THE
NIGHT...INSTABILITY WILL BE LIMITED SO DO NOT HAVE ANY THUNDER
MENTIONED. ALSO...TEMPERATURES SHOULD BE MILD ENOUGH SO THAT NO
PTYPE ISSUES AREA EXPECTED. THE ONLY EXECEPTION MAY THE ELEVATIONS
ABOVE 3500FT IN THE WAKE OF THE FRONT WHERE THERE COULD BE A BRIEF
PERIOD OF SNOW MIXED WITH RAIN.
BEHIND THE FRONT...DRYING NW FLOW SHOULD COMMENCE SO CLEARING SHOULD
OCCUR WEST TO EAST ACROSS THE AREA ON TUE. HIGH PRESSURE WILL BUILD
TOWARD THE AREA ON WED/THU. 12Z GFS TIME/HEIGHTS SUGGEST LOW LEVEL
MOISTURE MAY BE SUFFICENT FOR MORE CLOUDS ON WED/THU BUT WILL STAY
CLOSER TO THE DRYER ECM SOLUTION AND FORECAST MOSTLY CLEAR/CLEAR SKY
CONDITIONS. TEMPS WILL BEGIN THE PERIOD A LITTLE ABOVE AVERAGE AND
THEN COOL SLIGHTLY BELOW NORMAL BY THE END OF THE PERIOD.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
AT KCLT AND ELSEWHERE...CLEAR SKIES THROUGH THE PERIOD. N TO NE
WINDS EARLY THIS MORNING WILL STRENGTHEN WITH MIXING AFTER DAYBREAK.
IN FACT...LOW END GUSTS ARE LIKELY AT KCLT AND POSSIBLE AT KHKY.
WINDS BECOME NLY AT KGSP/KGMU FOR THE AFTERNOON AND LIGHT WSW AT
KAND WITH WEAK LEE TROF DEVELOPING. LIGHT N TO NE WINDS DEVELOP
DURING THE EVENING.
AT KAVL...GUSTY NNW WINDS WILL PERSIST TO NEAR DAYBREAK WHEN GUSTS
DIMINISH. GUST RETURN WITH MIXING AFTER DAYBREAK WITH LIGHT WINDS
DEVELOPING DURING THE EVENING. DO NOT EXPECT THE LOW CLOUDS NEAR THE
TN BORDER TO REACH THE AIRPORT.
OUTLOOK...DRY HIGH PRESSURE WILL PERSIST THROUGH THE WEEKEND.
MOISTURE AND RESTRICTIONS SHOULD RETURN BY LATE MONDAY AHEAD OF THE
NEXT APPROACHING COLD FRONT.
CONFIDENCE TABLE...
05-11Z 11-17Z 17-23Z 23-05Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL MED 78% HIGH 99% HIGH 100% HIGH 100%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...PAT
NEAR TERM...JDL/MCAVOY/RWH
SHORT TERM...LG
LONG TERM...LG
AVIATION...RWH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
305 AM CST FRI MAR 8 2013
.SHORT TERM...TODAY THROUGH SUNDAY NIGHT
305 AM CST FRI MAR 8 2013
MAIN FORECAST CONCERN IS ON PRECIPITATION TYPES LATE TONIGHT INTO EARLY
SATURDAY AND THEN AGAIN ON SUNDAY. ALSO OF CONCERN IS FLOODING
POTENTIAL WITH THE RAIN ON SATURDAY AND SATURDAY NIGHT.
07Z SURFACE ANALYSIS SHOWS RIDGE AXIS OVER EASTERN WISCONSIN
SOUTHWARD INTO EASTERN ILLINOIS. INFRARED SATELLITE IMAGERY JUST
SHOWING A FEW HIGH CLOUDS OVER IOWA AND ILLINOIS...WITH SOME PATCHY
STRATUS OVER NORTHWEST WISCONSIN. A LARGER STRATUS FIELD IS FOUND
OVER NORTH DAKOTA INTO NORTHWEST MINNESOTA.
08.00Z DETERMINISTIC MODELS OFFER SIMILAR SOLUTIONS THROUGH THE
PERIOD...WITH THE BIGGEST DIFFERENCES ON PRECIPITATION ONSET FRIDAY
NIGHT. GFS THE FASTEST OF ALL THE SOLUTIONS...WITH A NICE CLUSTERING
OF THE NAM/GEM AND ECMWF ALL SHOWING A SLOWER ONSET AND THUS DID GO
WITH THE SLOWER SOLUTIONS.
THE HIGH WILL CONTINUE TO SHIFT EASTWARD TODAY INTO THE GREAT LAKES.
MID AND HIGH LEVEL MOISTURE WILL BEGIN TO SPREAD INTO THE AREA LATER
THIS AFTERNOON. HOWEVER...850MB-700MB WARM ADVECTION ALONG WITH SOME
SUNSHINE WILL PUSH TEMPERATURES INTO THE 35 TO 40 DEGREE RANGE FOR
MOST OF THE AREA.
ATTENTION THEN TURNS TO LONGWAVE TROUGH MIGRATING EASTWARD OUT OF
THE WESTERN CONUS. SURFACE CYCLOGENESIS OCCURS TONIGHT...WITH MOISTURE
STREAMING NORTHWARD AHEAD OF IT. NOSE OF THE MOISTURE TRANSPORT
PUSHES INTO NORTHERN IOWA AND SOUTHEAST MINNESOTA THIS EVENING AS
WARM FRONT LIFTS INTO IOWA...THEN INTO THE FORECAST AREA SATURDAY.
EXPECT PRECIPITATION TO BREAK OUT ACROSS IOWA AND MINNESOTA DURING
THE EVENING AND THEN PUSH EASTWARD SPREADING ACROSS MUCH OF THE
REMAINDER OF THE AREA BETWEEN 06Z-12Z SATURDAY. THERMAL PROFILES
CONTINUE TO INDICATE A WINTRY MIX INITIALLY AS SURFACE TEMPERATURES
WILL BE AT OR SLIGHTLY BELOW THE FREEZING MARK WHEN THE PRECIPITATION
BEGINS. NOT EXPECTING ANY MAJOR ICING AS LOW LEVEL WARMING CONTINUES
IN WARM ADVECTION REGIME AND EXPECT A TRANSITION THEN TO ALL RAIN BY
MID MORNING SATURDAY. THUS EXPECTING LESS THAN A TENTH OF AN INCH OF
ICE. THERE IS SOME CONCERN THAT TEMPERATURES MAY EVEN STAY ABOVE
FREEZING AS THE MAIN COLD FRONT REMAINS WELL WEST OF THE AREA. LATER
SHIFTS WILL HAVE TO MONITOR FOR POSSIBLE ADVISORY FROM LATE TONIGHT
THROUGH EARLY SATURDAY MORNING.
TEMPERATURES ALOFT ARE EXPECTED TO RISE TO NEAR +6 DEGREES CELSIUS
ON SATURDAY...WITH CONTINUED LOW LEVEL WARMING INTO THE UPPER 30S TO
AROUND 40 AT THE SURFACE. THUS A TRANSITION TO ALL RAIN EXPECTED WHICH
LEADS TO ANOTHER POTENTIAL PROBLEM OF RAIN ON TOP OF THE HEAVY SNOW
PACK. MODELS HAVE BEEN CONSISTENT IN DROPPING BETWEEN 1/2 AND 1 INCH
OF LIQUID PRECIPITATION THROUGH SATURDAY NIGHT. THIS MODERATE
RAINFALL ON THE SNOWPACK COULD LEAD TO SOME FLOODING CONCERNS (SEE
HYDROLOGY SECTION BELOW FOR MORE DETAILS).
LATEST MODELS LOOK OP PUSH THE COLDER AIR IN A LITTLE QUICKER ON
SUNDAY THAN PREVIOUS RUNS WITH MODELS HINTING AT A DEFORMATION BAND
SITTING UP ACROSS THE NORTHERN SECTIONS OF THE FORECAST AREA. THUS
EXPECT RAIN TO TRANSITION TO SNOW AND COULD SEE UP TO AN INCH OF
ACCUMULATION IN AREAS NORTHWEST OF A ROCHESTER MINNESOTA TO
NEILLSVILLE WISCONSIN LINE. WILL HAVE TO WATCH THIS BAND AND HOW
QUICKLY THE RAIN CHANGES TO SNOW AS A LITTLE MORE IN ACCUMULATION
COULD BE POSSIBLE.
HIGH PRESSURE THEN BEGINS TO BUILD INTO THE AREA SUNDAY NIGHT AS THE
SURFACE LOW LIFTS NORTHEAST AWAY FROM THE AREA WITH CLEARING SKIES.
.LONG TERM...MONDAY THROUGH THURSDAY
305 AM CST FRI MAR 8 2013
RATHER PROGRESSIVE FLOW EXPECTED DURING THIS PERIOD. 08.00Z GFS MORE
ZONAL THAN THE 08.00Z ECMWF AS THE ECMWF KEEPS A CLOSED 500MB LOW
JUST NORTH OF LAKE SUPERIOR AT THE BEGINNING OF THE PERIOD THEN
PUSHING IT SLOWLY EASTWARD WITH TIME. IN EITHER CASE...WEAK WAVES
IN THE FLOW LIKELY TO TRACK ACROSS THE AREA...WITH A LOW PROBABILITY
OF PRECIPITATION TUESDAY AND WEDNESDAY. BELOW NORMAL TEMPERATURES
EXPECTED MONDAY...BUT WILL RISE TO NEAR NORMAL TUESDAY THROUGH
THURSDAY...WHICH GENERALLY RANGES FROM 35 TO 40 ACROSS THE AREA.
DEPENDING ON TIMING OF PRECIPITATION...IT WOULD LIKELY BE IN THE FORM
OF RAIN DURING THE DAY AND SNOW AT NIGHT.
&&
.AVIATION...THROUGH 06Z SATURDAY
1127 PM CST THU MAR 7 2013
STILL SOME CONCERN THAT FOG WILL FORM OVERNIGHT DROPPING THE
VISIBILITY TO MVFR. THE 08.00Z NAM AND 08.03Z RAP HAVE BACKED OFF
THE IDEA THAT SATURATION WILL OCCUR AT KLSE AND WITH A 6 DEGREE
TEMP/DEW POINT SPREAD...THIS SEEMS REASONABLE. WILL NOT TOTALLY
DROP THE MENTION OF FOG AT KLSE BUT JUST HAVE IT IN A TEMPO GROUP
FOR LATE TONIGHT. THE SAME SCENARIO IS SHOW FOR KRST BUT THE
VISIBILITY HAS BEEN SLOWLY DROPPING THERE...SO CONFIDENCE IS NOT
AS HIGH THAT THE MODELS ARE CORRECT. WITH THE VISIBILITY ALREADY
GOING DOWN WILL CONTINUE TO SHOW SOME MVFR FOG DEVELOPING AND
LASTING THROUGH THE MIDDLE OF FRIDAY MORNING. ONCE THE FOG IS
GONE...VFR CONDITIONS EXPECTED FOR THE REMAINDER OF THE NIGHT. THE
NEXT SYSTEM TO IMPACT THE AREA IS STILL OFF THE CALIFORNIA COAST
THIS EVENING. THE NAM CONTINUES TO BE A SLOWER SOLUTION BRINGING
THIS SYSTEM IN AND HOLDS THE PRECIPITATION BACK UNTIL WELL AFTER
09.06Z WHILE THE 08.00Z GFS WOULD HAVE PRECIPITATION FALLING AT
BOTH TAF SITES BY 09.06Z. THE 07.12Z ECMWF IS BETWEEN THESE TWO
SOLUTIONS BUT HOLDS THE PRECIPITATION BACK UNTIL AFTER 09.06Z AS
WELL. GIVEN THAT THE SYSTEM IS STILL OFF THE COAST AND THAT THE
MODELS TEND TO BE TOO FAST WITH SOUTHWEST FLOW SYSTEMS...WILL NOT
INTRODUCE ANY PRECIPITATION AT THIS TIME.
&&
.HYDROLOGY...TONIGHT THROUGH SUNDAY
305 PM CST THU MAR 7 2013
RAINFALL AND SNOWMELT FRIDAY NIGHT THROUGH SATURDAY NIGHT MAY LEAD
TO RUNOFF ISSUES INTO AREA CREEKS AND RIVERS. CURRENTLY EXPECTING
ANYWHERE FROM 1/2 TO 1 INCH OF LIQUID TO FALL ONTO THE SNOWPACK IN
PLACE. DUE TO THE DEEPER SNOWPACK...MUCH OF THIS RAINFALL CAN BE
ABSORBED. HOWEVER...IF RAINFALL BECOMES HEAVIER OR MORE SNOWMELT
THAN ANTICIPATED OCCURS...RUNOFF MAY BECOME AN ISSUE...ESPECIALLY
GIVEN THE FACT THAT THE TOP LAYER OF GROUND IS SOLID WITH CONCRETE
FROST. WILL BE ISSUING A HYDROLOGIC OUTLOOK PRODUCT TO COVER THIS
INCREASING CONCERN.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
305 AM CST FRI MAR 8 2013
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...RABERDING
LONG TERM...RABERDING
AVIATION...04
HYDROLOGY...DAS/JLR
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1127 PM CST THU MAR 7 2013
.SHORT TERM...TONIGHT THROUGH SUNDAY
213 PM CST THU MAR 7 2013
MAIN CONCERN FOCUSED ON STORM SYSTEM AFFECTING THE AREA FRIDAY NIGHT
THROUGH SUNDAY WITH A WINTRY MIX AND SIGNIFICANT RAINFALL.
WATER VAPOR THIS AFTERNOON SHOWS A BROAD MID-LEVEL TO SURFACE RIDGE
OF HIGH PRESSURE ACROSS THE CENTRAL CONUS INCLUDING THE UPPER
MISSISSIPPI RIVER REGION. SOME LINGERING STRATOCUMULUS TRAPPED UNDER
THE SUBSIDENCE INVERSION WERE NOTED JUST SOUTH OF THE AREA OVER
EASTERN IA/NORTHERN IL...OTHER THAN THAT...JUST SOME OCCASIONAL
CIRRUS WAS DRIFTING OVER THE FORECAST AREA WITH TEMPERATURES AS OF 2
PM IN THE UPPER 20S TO THE MIDDLE 30S.
07.12Z MODELS COMING INTO VERY GOOD AGREEMENT THROUGH THE SHORT
TERM...LENDING TO HIGHER OVERALL FORECAST CONFIDENCE.
LOOK FOR THE SURFACE RIDGE OF HIGH PRESSURE TO SLIP EAST INTO THE
GREAT LAKES REGION OVERNIGHT. THIS WILL TURN WINDS TO A
SOUTHEASTERLY DIRECTION IN THE 5 TO 10KT RANGE. MOSTLY CLEAR/PARTLY
CLOUDY SKIES AND VERY LIGHT WINDS INITIALLY TONIGHT ACROSS THE EAST
EXPECTED TO ALLOW TEMPERATURES TO FALL OFF PRETTY GOOD. EXPECTING
LOWS FOR AREAS ALONG/NORTHEAST IF I-94 IN THE SINGLE DIGITS ABOVE
ZERO IN THE FAVORED COLD LOWER-LYING SPOTS. ELSEWHERE ACROSS THE
AREA...EXPECTING LOWS IN THE TEENS. QUIET CONDITIONS EXPECTED INTO
FRIDAY. WILL HAVE TO WATCH CLOUD TRENDS THOUGH AS MODEL
SOUNDINGS/NAM BUFR INDICATING AN INCREASE IN STRATUS AS WARMING
TAKES PLACE OVER THE SNOWPACK IN PLACE. HAVE ADJUSTED CLOUD GRIDS
ACCORDINGLY TO REFLECT THIS.
FOCUS THEN SHIFTS TO THE STORM AFFECTING THE STORM SYSTEM AFFECTING
THE AREA FRIDAY NIGHT THROUGH SUNDAY.
AS STATED ABOVE...LATEST RUN OF THE MODELS SHOWING VERY GOOD
AGREEMENT ON A GOOD SLUG OF MOISTURE MOVING INTO THE AREA FRIDAY
NIGHT AND BECOMING HEAVIEST DURING THE DAY SATURDAY INTO SATURDAY
EVENING AHEAD OF LOW PRESSURE MOVING OUT OF THE CENTRAL PLAINS. WILL
HAVE TO DEAL WITH 2 FACETS OF THIS STORM. THE FIRST WILL BE
PRECIPITATION TYPES AT ONSET FRIDAY NIGHT LASTING INTO SATURDAY
MORNING. VERTICAL THERMAL PROFILES DEPICTED BY THE MODELS CONTINUE
TO SUPPORT A WINTRY MIX OF FREEZING RAIN/RAIN/SLEET FOR THE AREA.
THEN...LOOK FOR A TRANSITION IN THE PRECIPITATION TO ALL RAIN DURING
THE DAY SATURDAY AS TEMPERATURES ALOFT WARM TO AROUND 8C WITH LOWER
BOUNDARY LAYER TEMPERATURES TRENDING UPWARD AS WELL. THE SECOND
FACET OF THIS STORM WILL BE MODERATE RAINFALL EXPECTED THROUGH THE
REMAINDER OF SATURDAY INTO SATURDAY EVENING. PRECIPITABLE WATER
VALUES CLIMB INTO THE 250-300 PERCENT ABOVE NORMAL RANGE...
CORRESPONDING TO 0.75-1.00 INCH RANGE. CONCERNS ARISE AS FAR AS
RUNOFF BECOMING AN ISSUE. SEE HYDROLOGY DISCUSSION BELOW FOR
DETAILS.
WITH ALL THIS IN MIND...WILL LIKELY HAVE TO ISSUE A WINTER WEATHER
ADVISORY FOR FRIDAY NIGHT INTO SATURDAY MORNING FOR THE WINTRY MIX
GIVEN THE POTENTIAL FOR SOME ICING OF AROUND A TENTH OF AN INCH.
WILL PASS THIS ONTO THE MIDSHIFT TO ASSESS WITH LATEST AVAILABLE
MODEL DATA.
ANOTHER CONCERN TO CONTEND WITH WILL BE FOG POTENTIAL FRIDAY NIGHT
THROUGH SATURDAY NIGHT WITH LOWER BOUNDARY LAYER BECOMING SATURATED
AND LIGHT WINDS OVER THE MELTING SNOWPACK.
EXPECTING THE PRECIPITATION TO SLOWLY TRANSITION OVER TO SNOW FROM
NORTHWEST TO SOUTHEAST SATURDAY NIGHT...THEN SLOWLY TAPERING OFF
SUNDAY AS THE LOW PULLS INTO SOUTHERN ONTARIO. PERHAPS 1-2 INCHES OF
SNOW ACCUMULATION MAY BEE SEEN NORTHWEST OF A LINE FROM BLACK RIVER
FALLS WI TO AUSTIN MN.
.LONG TERM...MONDAY THROUGH THURSDAY
213 PM CST THU MAR 7 2013
07.12Z MEDIUM RANGE MODELS SHOWING SOME DIFFERENCES IN THE LONG TERM
PERIOD. THE GFS IS TRENDING TOWARD A MORE HIGH-ZONAL FLOW ACROSS THE
CONUS WHEREAS THE ECMWF WHICH SEEMS TO HAVE MORE RUN-TO-RUN
CONSISTENCY MAINTAINS A NORTHWEST FLOW INTO THE AREA. HAVE TAKEN A
BLEND APPROACH AT THIS POINT AND CARRIED A SLIGHT CHANCE OF
RAIN/SNOW MIX ON TUESDAY AS A WEAK LOW MOVES SOUTHEAST THROUGH
CANADA INTO THE GREAT LAKE REGION. THE REST OF THE PERIOD LOOKS DRY
AT THIS TIME. TEMPERATURES THROUGH THE PERIOD LOOK TO BE RIGHT
AROUND NORMAL WITH HIGHS IN THE MID 30S TO AROUND 40.
&&
.AVIATION...THROUGH 06Z SATURDAY
1127 PM CST THU MAR 7 2013
STILL SOME CONCERN THAT FOG WILL FORM OVERNIGHT DROPPING THE
VISIBILITY TO MVFR. THE 08.00Z NAM AND 08.03Z RAP HAVE BACKED OFF
THE IDEA THAT SATURATION WILL OCCUR AT KLSE AND WITH A 6 DEGREE
TEMP/DEW POINT SPREAD...THIS SEEMS REASONABLE. WILL NOT TOTALLY
DROP THE MENTION OF FOG AT KLSE BUT JUST HAVE IT IN A TEMPO GROUP
FOR LATE TONIGHT. THE SAME SCENARIO IS SHOW FOR KRST BUT THE
VISIBILITY HAS BEEN SLOWLY DROPPING THERE...SO CONFIDENCE IS NOT
AS HIGH THAT THE MODELS ARE CORRECT. WITH THE VISIBILITY ALREADY
GOING DOWN WILL CONTINUE TO SHOW SOME MVFR FOG DEVELOPING AND
LASTING THROUGH THE MIDDLE OF FRIDAY MORNING. ONCE THE FOG IS
GONE...VFR CONDITIONS EXPECTED FOR THE REMAINDER OF THE NIGHT. THE
NEXT SYSTEM TO IMPACT THE AREA IS STILL OFF THE CALIFORNIA COAST
THIS EVENING. THE NAM CONTINUES TO BE A SLOWER SOLUTION BRINGING
THIS SYSTEM IN AND HOLDS THE PRECIPITATION BACK UNTIL WELL AFTER
09.06Z WHILE THE 08.00Z GFS WOULD HAVE PRECIPITATION FALLING AT
BOTH TAF SITES BY 09.06Z. THE 07.12Z ECMWF IS BETWEEN THESE TWO
SOLUTIONS BUT HOLDS THE PRECIPITATION BACK UNTIL AFTER 09.06Z AS
WELL. GIVEN THAT THE SYSTEM IS STILL OFF THE COAST AND THAT THE
MODELS TEND TO BE TOO FAST WITH SOUTHWEST FLOW SYSTEMS...WILL NOT
INTRODUCE ANY PRECIPITATION AT THIS TIME.
&&
.HYDROLOGY...
213 PM CST THU MAR 7 2013
RAINFALL AND SNOWMELT FRIDAY NIGHT THROUGH SATURDAY NIGHT MAY LEAD
TO RUNOFF ISSUES INTO AREA CREEKS AND RIVERS. CURRENTLY EXPECTING
ANYWHERE FROM 1/2 TO 1 INCH OF LIQUID TO FALL ONTO THE SNOWPACK IN
PLACE. DUE TO THE DEEPER SNOWPACK...MUCH OF THIS RAINFALL CAN BE
ABSORBED. HOWEVER...IF RAINFALL BECOMES HEAVIER OR MORE SNOWMELT
THAN ANTICIPATED OCCURS...RUNOFF MAY BECOME AN ISSUE...ESPECIALLY
GIVEN THE FACT THAT THE TOP LAYER OF GROUND IS SOLID WITH CONCRETE
FROST. WILL BE ISSUING A HYDROLOGIC OUTLOOK PRODUCT TO COVER THIS
INCREASING CONCERN.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
213 PM CST THU MAR 7 2013
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM...DAS
AVIATION...04
HYDROLOGY...DAS
AREA FORECAST DISCUSSION
NWS PUEBLO CO
507 AM MST FRI MAR 8 2013
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 506 AM MST FRI MAR 8 2013
CLOUDS ARE INCREASING OVR WRN CO THIS MORNING AHEAD OF THE UPPER
LEVEL LOW THAT SATELLITE IMAGES SHOW OFF THE SRN CA COAST. A THICK
BAND OF CLOUDS HAS ALSO MOVED UP OVR THE SERN CORNER OF THE
STATE...BUT THAT SHOULD PUSH EAST LATER THIS MORNING. BY EVENING THE
UPR LOW CENTER IS EXPECTED TO MOVE OVR THE CA AND AZ BORDER AREA.
BOTH THE HRRR AND NAM12 SHOWING PCPN HOLDING OFF OVR THE SWRN MTS
UNTIL AT LEAST LATE MORNING...BUT THEN WE SHOULD SEE PCPN ALL ALONG THE
CONTDVD THIS AFTERNOON...WITH SCT TO LIKELY POPS SPREADING OVR MUCH
OF THE ERN MTS AS WELL AND OVR THE SAN LUIS VALLEY...AND MAINLY
ISOLD CHANCE FOR RAIN OVR THE SERN PLAINS. FOR THIS AFTERNOON THE
NAM IS SHOWING A FEW HUNDRED JOULES OF CAPES OVR THE MTS AND
PORTIONS OF THE I-25 CORRIDOR...WITH LAPSE RATES OF 8-9C/KM OVR THE
FORECAST AREA. WL GO WITH SOME ISOLD THUNDERSTORMS CHANCES THIS
AFTERNOON AND EARLY EVENING. FOR THIS AFTERNOON THE EASTERN SAN JUAN
MTS SHOULD BE THE AREA THAT RECEIVES THE HEAVIEST SNOW...WITH THE
REST OF THE CONTDVD SEEING SNOW...BUT NOT AS MUCH. DURING THE
AFTERNOON SOME STRONG SOUTHERLY WINDS ARE EXPECTED TO DEVELOP OVR
THE FAR SERN CORNER OF THE STATE WITH GUSTS OF 30-40 MPH. MIN RH
VALUES IN THIS AREA ARE EXPECTED TO BE NR 15 PERCENT. HOWEVER FUELS
IN THIS AREA ARE NOT CONSIDERED TO BE CRITICAL. HAVE ISSUED A WINTER
WX ADVISORY FOR ZONE 67 AS WELL AND WL START IT IN THE LATE
AFTERNOON TODAY. TEMPS IN THE EARLY AFTERNOON WL LIKELY BE TOO WARM
TO SEE SNOW OR AT LEAST ANY REAL ACCUMULATIONS UNTIL TEMPS COOL
TOWARD EVENING AND OVERNIGHT.
BY 12Z SAT THE UPR LOW CENTER IS EXPECTED TO MOVE INTO THE SW CORNER
OF CO. AS THIS OCCURS OVERNIGHT A DRY SLOT DEVELOPS OVR THE SERN
PLAINS...AND SHOULD SEE DECREASING CHANCES FOR PCPN OVR THE SAN LUIS
VALLEY AND SERN MTS. AT THE SAME TIME SNOW WL CONTINUE ALONG THE
CONTDVD WITH THE EASTERN SAN JUAN MTS STILL BEING THE MOST FAVORED
LOCATION FOR SIGNIFICANT SNOWFALL.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 506 AM MST FRI MAR 8 2013
...QUICK MOVING STORM TO BRING SNOW AND BLOWING SNOW TO THE AREA
SATURDAY...
SATURDAY-SATURDAY NIGHT...LATEST MODELS REMAIN IN GOOD AGREEMENT OF
A POTENT UPPER LOW ACROSS THE SOUTHERN CALIFORNIA COAST THIS MORNING
LIFTING OUT INTO THE FOUR CORNERS REGION LATE TONIGHT WHICH THEN
CONTINUES TO TRANSLATE ACROSS SOUTHERN COLORADO THROUGH THE DAY
SATURDAY AND INTO NORTHWESTERN KANSAS SATURDAY NIGHT. MOVEMENT OF
THIS SYSTEM KEEPS MODERATE TO HEAVY SNOWFALL ACROSS THE CONTDVD
FRIDAY NIGHT AND SATURDAY WITH DEFORMATION BAND PRECIPITATION
SPREADING EAST ACROSS SOUTH CENTRAL COLORADO AND THE EASTERN MTS
SATURDAY MORNING AND AFTERNOON.
MODELS REMAIN CONSISTENT WITH STRONG NORTHERLY WINDS DEVELOPING
ACROSS THE EASTERN PLAINS LATE SATURDAY MORNING AND PERSISTING
THROUGH THE EARLY EVENING AS AN ASSOCIATED COLD FRONT BLASTS ACROSS
THE PLAINS. PRECIPITATION TYPE STILL IN QUESTION ACROSS THE PLAINS
THOUGH MODEL SOUNDINGS INDICATING PRECIP RAPIDLY CHANGING OVER THE
SNOW AOA 6K FT SATURDAY MORNING AND POSSIBLY LOWERING TO 4K FT UNDER
THE HEAVIER BANDS AS THE SYSTEM LIFTS OUT ACROSS THE EASTERN PLAINS
SATURDAY AFTERNOON AND EVENING.
WITH THAT SAID...HAVE UPGRADED WINTER STORM WATCH TO A BLIZZARD
WARNING FOR NORTHERN EL PASO COUNTY WITH 4-9 INCHES ALONG WITH
STRONG NORTHERLY WINDS UP TO 30 MPH GUSTING TO NEAR 50 MPH AT
TIMES...ESPECIALLY SATURDAY AFTERNOON. HAVE ALSO UPGRADED TELLER
COUNTY AND THE RAMPART RANGE TO WINTER STORM WARNING WITH AMOUNTS
RANGING FROM 6 TO 12 INCHES AND HAVE ISSUED WINTER WEATHER
ADVISORIES FOR LAKE COUNTY...THE WESTERN MOSQUITO RANGE BELOW 9000
FEET AND NORTHWESTERN FREMONT COUNTY ABOVE 8500 FEET. HAVE ALSO
ISSUED A WINTER STORM WATCH FOR THE SANGRE DE CRISTO AND WET MTS
FROM SATURDAY MORNING THROUGH SATURDAY NIGHT. GFS IS STILL A BIT
HEAVY HANDED WITH AMOUNTS ACROSS THE SOUTHEAST MTS AS WELL AS UNDER
THE BANDS AND WILL NEED TO CONTINUE TO MONITOR FOR POSSIBLE
ADDITIONS TO ADVISORIES AND WARNINGS.
SUNDAY-WEDNESDAY...MODEL CONSENSUS CONTINUES TO INDICATE WARMER AND
DRY CONDITIONS ACROSS THE AREA THROUGH THE REST OF EXTENDED PERIOD
WITH MODERATE WESTERLY FLOW ACROSS THE REGION.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 506 AM MST FRI MAR 8 2013
EXPECTED VFR CONDITIONS AT KPUB AND KCOS TODAY AND TONIGHT. LATE
THIS AFTERNOON AND THIS EVENING THERE COULD BE A FEW SHOWERS OR EVEN
A THUNDERSTORM AT OR IN THE VCNTY. KALS SHOULD HAVE VFR CONDITIONS
BUT LATE THIS AFTERNOON SOME SHOWERS OR EVEN A THUNDERSTORM COULD
RESULT IN BRIEF MVFR CONDITIONS. THERE IS ALSO THE POSSIBILITY OF
SOME STRATUS OR BR TOWARD MORNING CAUSING MVFR CONDITIONS...ALTHOUGH
CONFIDENCE IN THIS OCCURRING IT TOO LOW TO INCLUDE IN THE TAF AT THIS
TIME.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 5 AM TO 5 PM MST SATURDAY FOR
COZ059-063-076.
WINTER STORM WATCH FROM SATURDAY MORNING THROUGH SATURDAY
EVENING FOR COZ072>075-079-080.
WINTER STORM WARNING FROM 1 PM THIS AFTERNOON TO 11 PM MST
SATURDAY FOR COZ058-060.
WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO 5 PM MST
SATURDAY FOR COZ067.
WINTER STORM WARNING FROM 11 AM THIS MORNING TO 8 PM MST
SATURDAY FOR COZ066-068.
WINTER STORM WARNING FROM 5 AM TO 8 PM MST SATURDAY FOR COZ081-
082.
BLIZZARD WARNING FROM 5 AM TO 8 PM MST SATURDAY FOR COZ084.
&&
$$
SHORT TERM...28
LONG TERM...MW
AVIATION...28
AREA FORECAST DISCUSSION
NWS NEW YORK NY
1054 AM EST FRI MAR 8 2013
.SYNOPSIS...
DEEP LOW PRESSURE REMAINS NEARLY STATIONARY WELL TO THE SOUTHEAST
THROUGH TODAY...THEN SLIDES SOUTHEAST TONIGHT. HIGH PRESSURE
BUILDS OVER THE REGION FOR THE WEEKEND INTO MONDAY. MULTIPLE LOW
PRESSURE SYSTEMS IMPACT THE NORTHEAST THROUGH MID WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
MONITORING BAND OF MODERATE TO HEAVY SNOW THAT HAS DESCENDED UPON
MOST OF THE STATE OF CT FROM THE NORTHEAST. LATEST HRRR INDICATES
THIS BAND SHOULD CONTINUE TO DESCEND INTO COASTAL CT AND
EVENTUALLY LONG ISLAND AS THE DAY PROGRESSES. UPGRADED SRN
WESTCHESTER AND NORTHERN NASSAU...AS WELL AS MOST OF COASTAL
CT...TO WINTER STORM WARNINGS WHERE SPOTTER REPORTS INDICATED 6-8
INCHES OF ACCUMULATION...WITH MORE TO FOLLOW WITH THE
AFOREMENTIONED BAND INTO THIS AFTERNOON. ALSO SEEING SOME SPOTTY 6
INCH TOTALS ACROSS PARTS OF NW SUFFOLK COUNTY...SNOW THERE HAS
LIGHTENED UP FOR THE TIME BEING...BUT AN ADDITIONAL 1-3 INCHES OF
ACCUMULATION MAY BE POSSIBLE WITH THE BAND NOW OVER CT DURING THE
LATE MORNING AND AFTERNOON. WHILE AMTS OVER SUFFOLK SHOULD RANGE
FROM 4-8 INCHES...HAVE NOT UPGRADED TO A WARNING THERE MAINLY DUE
TO THE RELATIVELY LONG DURATION OF SNOWFALL.
ELSEWHERE...WARNINGS/ADVISORIES THAT WERE ALREADY IN EFFECT WERE
EXTENDED A LITTLE LONGER INTO EARLY AFTERNOON ACROSS NYC METRO
AND NE NJ...AND WERE EXTENDED INTO THE AFTERNOON FARTHER EAST.
GUSTY NORTHERLY WINDS WILL PICK UP THROUGH THE DAY...WITH WINDS OF
20 TO 30 MPH AND GUSTS 35 TO 45 MPH. THERE IS A LOW PROBABILITY OF
WIND ADVISORY WINDS.
WITH CLOUDS AND PRECIP TEMPS WILL RUN SEVERAL DEGREES BELOW AVG...
AROUND 40 IN NYC METRO...AND MID/UPPER 30S ELSEWHERE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...
STACKED LOW PRESSURE GRADUALLY DRIFTS FARTHER OFFSHORE TONIGHT WITH
RIDGING SURFACE/ALOFT GRADUALLY BUILDING TOWARDS THE REGION. THIS
WILL ALLOW FOR A GRADUAL SUBSIDING OF WINDS AND CLEARING SKIES.
RIDGING CONTINUES TO BUILDS INTO THE REGION ON SATURDAY...WITH GUSTY
NORTHERLY WINDS IN THE MORNING GRADUALLY RELAXING THROUGH THE
AFTERNOON. OTHERWISE...MOSTLY SUNNY SKIES AND SLIGHTLY ABOVE
SEASONABLE TEMPS EXPECTED IN A MODERATING AIR MASS.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
GENERALLY DECENT MODEL AGREEMENT FOR THE WEEKEND AND INTO THE
BEGINNING OF THE COMING WEEK. SOME MODEL DIVERGENCE ON THE HANDLING
OF THE FIRST LOW PRESSURE SYSTEM AND ACCOMPANYING COLD FRONT LATER
MONDAY AND THE DEVELOPMENT OF A SECONDARY LOW INTO TUESDAY.
SURFACE HIGH PRESSURE EXTENDS DOWN ACROSS THE EASTERN SEABOARD SAT
NIGHT INTO SUNDAY WHILE AN UPPER LEVEL RIDGE SETS UP OVERHEAD BY
SUNDAY. THIS WILL PRODUCE QUIET CONDITIONS...WITH A LIGHT FLOW AND
PARTLY CLOUDY SKIES. WARM AIR ADVECTION INCREASES SUNDAY AS THE HIGH
PUSHES TO THE EAST...SHIFTING WINDS TO THE SOUTHEAST. AS A
RESULT...HIGH TEMPS ON SUNDAY WILL PUSH INTO THE UPPER 40S TO LOWER
50S...A FEW DEGREES ABOVE NORMAL.
A LOW PRESSURE SYSTEM MOVING THROUGH SOUTHERN CANADA WILL APPROACH
WITH A COLD FRONT MONDAY. STRONG SOUTHERLY FLOW AHEAD OF THIS FRONT
WILL KEEP INCREASING THE WAA...WITH HIGH TEMPS ON MONDAY HITTING THE
UPPER 50S AROUND THE NYC METRO AREA...AND LOWER 50S ELSEWHERE. A
WEAK SHORTWAVE MOVING THROUGH MONDAY MORNING COULD BRING A SLIGHT
CHC OF RAIN. CAPPED POPS OFF AT HIGHER END CHC FOR MONDAY AFTN INTO
TUES WITH SOME MODEL DISCREPANCIES ON THE HANDLING OF THE FRONT AND
A DEVELOPING LOW OVER THE TENNESSEE VALLEY REGION AT THE END OF THE
FRONT. THE MODELS GENERALLY AGREE THAT THE COLD FRONT DOES NOT
ACTUALLY PUSH THROUGH THE TRI STATE AREA. BUT THE 00Z ECMWF IS MUCH
MORE PROGRESSIVE ON THE SECONDARY LOW MOVING THROUGH THE EASTERN
GREAT LAKES REGION MONDAY NIGHT...AND THEN DRAGGING A COLD
FRONT/TROUGH THROUGH TUESDAY...WHILE THE 00Z GFS IS FURTHER TO THE
EAST WITH THE CENTER DIRECTLY OVER THE TRI STATE REGION AND A GOOD
12 HOURS SLOWER. SO WHILE THE TIMING OF THE PCPN IS STILL TO BE
DETERMINED...HIGHER CONFIDENCE THAT THE TRACK OF EITHER SOLUTION
WOULD KEEP ANY PCPN AS RAIN OVER THE ENTIRE AREA THROUGH TUESDAY.
MODELS CONTINUE TO DIVERGE MIDWEEK WITH THE ECMWF DEEPENING AN UPPER
LEVEL CLOSED LOW OVER THE NORTHEAST WHILE THE GFS RETURNS TO ALMOST
A ZONAL FLOW WITH HIGH PRESSURE AT THE SURFACE. WITH THE 00Z MODEL
RUNS TRENDING MUCH DIFFERENT THAN PREVIOUS RUNS...AND WITH SUCH
DIFFERENCES BETWEEN THEMSELVES EVEN...WILL NOT MAKE MANY CHANGES FOR
THE LATTER PART OF THE PERIOD. SLIGHT CHC POPS REMAIN IN THE
FORECAST FOR WED INTO THURS TO ACCOUNT FOR A DEVELOPING TROUGH OVER
NEW ENGLAND. WEAK COLD AIR ADVECTION WILL BE SLOW TO MOVE INTO THE
REGION...SO TEMPS REMAIN NEAR TO SLIGHTLY ABOVE NORMAL FOR MID WEEK.
WITH TEMPS GRADUALLY DECREASING...SHOULD SEE AT LEAST MIXED
PCPN...WITH POSSIBLY ALL SNOW WED NIGHT.
&&
.AVIATION /16Z FRIDAY THROUGH TUESDAY/...
SNOW ASSOCIATED WITH LOW PRESSURE OFFSHORE WILL PRESENT WIDESPREAD
IFR/LIFR CONDITIONS WITH VLIFR AT TIMES INTO EARLY AFTERNOON WITH
HEAVIER SNOW. THERE COULD BE SOME AREAS THAT ARE OCCASIONALLY
MVFR BUT THINK THIS WILL BE QUITE LOCALIZED. SLOW IMPROVEMENT
LATER IN THE AFTERNOON WITH LIGHTER SNOWFALL AND MORE IN THE WAY
OF MVFR/IFR CONDITIONS. LOW CONFIDENCE ON EXACT TIMING OF
IMPROVING CONDITIONS AND END TIME OF SNOWFALL WITH AMENDMENTS
LIKELY TO REFINE THIS TIMING AS WELL AS WHEN VLIFR BECOMES LIKELY.
HIGHER CONFIDENCE OF DRYING AND IMPROVING CONDITIONS THIS EVENING
AFTER 00Z.
HIGHER CONFIDENCE WITH WIND FORECAST. WIND DIRECTION STAYING IN
THE 340-360 RANGE AND SUSTAINED SPEEDS OF 15-25 KT WITH GUSTS IN
THE 25-35 KT RANGE WITH THE PEAK GUSTS THIS AFTERNOON. WINDS
GRADUALLY LOWER TONIGHT. LOW LEVEL WINDS INCREASE WITH THE LOW
LEVEL JET MOVING IN...INCREASING WINDS TO 45-50 KT AT 2KFT.
NY METRO ENHANCED AVIATION WEATHER SUPPORT...
DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN
BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)
KEWR FCSTER COMMENTS: AMENDMENTS LIKELY TO REFINE TIMING THE END
OF SNOW AS WELL AS LOWER CIGS AND VSBY...WHICH COULD BE OFF BY 1-2
HOURS. OCCASIONAL HEAVY SNOW WITH VLIFR POSSIBLE.
THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH IMPLIES
SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD.
KJFK FCSTER COMMENTS: AMENDMENTS LIKELY TO REFINE TIMING THE END
OF SNOW AS WELL AS LOWER CIGS AND VSBY...WHICH COULD BE OFF BY 1-2
HOURS. OCCASIONAL HEAVY SNOW WITH VLIFR POSSIBLE.
KLGA FCSTER COMMENTS: AMENDMENTS LIKELY TO REFINE TIMING THE END
OF SNOW AS WELL AS LOWER CIGS AND VSBY...WHICH COULD BE OFF BY 1-2
HOURS. OCCASIONAL HEAVY SNOW WITH VLIFR POSSIBLE.
KTEB FCSTER COMMENTS: AMENDMENTS LIKELY TO REFINE TIMING THE END
OF SNOW AS WELL AS LOWER CIGS AND VSBY...WHICH COULD BE OFF BY 1-2
HOURS. OCCASIONAL HEAVY SNOW WITH VLIFR POSSIBLE.
KHPN FCSTER COMMENTS: AMENDMENTS LIKELY TO REFINE TIMING THE END
OF SNOW AS WELL AS LOWER CIGS AND VSBY...WHICH COULD BE OFF BY 1-2
HOURS. OCCASIONAL HEAVY SNOW WITH VLIFR POSSIBLE.
KISP FCSTER COMMENTS: AMENDMENTS LIKELY TO REFINE TIMING THE END
OF SNOW AS WELL AS LOWER CIGS AND VSBY...WHICH COULD BE OFF BY 1-2
HOURS. OCCASIONAL HEAVY SNOW WITH VLIFR POSSIBLE.
OUTLOOK FOR 06Z SATURDAY THROUGH WEDNESDAY...
.TONIGHT...VFR WITH DECREASING NORTH WINDS.
.SAT-SUN...VFR.
.MON...VFR...INCREASING S WINDS LATE IN THE DAY.
.TUE...COLD FRONTAL PASSAGE WITH RAIN SHOWERS. SUB-VFR CONDITIONS
EXPECTED.
.WED...VFR.
&&
.MARINE...
GALES EXPECTED ON ALL WATERS TODAY AS THE PRESSURE GRADIENT
SLIGHTLY TIGHTENS BETWEEN STATIONARY OFFSHORE LOW PRESSURE AND
HIGH PRESSURE BUILDING INTO WESTERN NY. GALES SHOULD THEN
GRADUALLY SUBSIDE TO SCA FROM W TO E THIS EVENING...AND THEN
GRADUALLY FALLING BELOW SCA ON SAT. LONG PERIOD EASTERLY SWELLS
WILL LIKELY KEEP SEAS HIGH ON THE OCEAN INTO SAT...10-15 FT.
SEAS ON THE OCEAN WILL REMAIN ELEVATED AROUND 5 FT SAT NIGHT INTO
SUNDAY...GRADUALLY DIMINISHING AS THE WINDS DECREASE WITH HIGH
PRESSURE BUILDS IN. A BRIEF PERIOD OF SUB-SCA CONDITIONS IS EXPECTED
MONDAY BEFORE WINDS AND SEAS INCREASE ONCE AGAIN WITH THE NEXT LOW
PRESSURE SYSTEM TO SCA LEVELS. DEPENDING ON THE TRACK OF THE LOW
MIDWEEK...THERE MAY BE A CHANCE OF GALES ON THE OCEAN WATERS. BUT
VERY LOW CONFIDENCE AT THIS TIME OF OCCURRING.
&&
.HYDROLOGY...
TOTAL LIQUID EQUIVALENT QPF TONIGHT THROUGH FRI IS FORECAST TO
RANGE FROM AROUND ONE THIRD TO THREE QUARTERS OF AN INCH.
HYDRO RELATED ISSUES ARE NOT ANTICIPATED AT THIS TIME.
DRY WEATHER FOR THE WEEKEND...THEN LIGHT TO MODERATE PRECIPITATION
AMOUNTS WILL BE POSSIBLE MONDAY NIGHT INTO TUESDAY.
&&
.TIDES/COASTAL FLOODING...
RESIDUAL SURGE OF 1 1/2 TO 2 1/2 FT WILL RESULT IN WIDESPREAD
MINOR COASTAL FLOODING EXPECTED WITH THIS MORNING HIGH TIDES
ACROSS THE ENTIRE COAST.
FOR THE LOWER HIGH TIDE THIS AFT/EVE WATER LEVELS WILL LIKELY ONLY
TOUCH MINOR LEVELS ACROSS THE SOUTH SHORE BAYS OF LI...TWIN FORKS
AND WESTERN AND CENTRAL LI SOUND...INCLUDING THE NORTH SHORE OF LI.
MODERATE BEACH EROSION ISSUES WILL CONTINUE INTO SATURDAY FOR
OCEAN FACING BEACHES AND TWIN FORKS OF LI WITH BREAKERS BETWEEN 7
TO 11 FT...HIGHEST EAST OF MORICHES INLET.
LOOKING TOWARDS THE WEEKEND...FURTHER INCREASES IN ASTRONOMICAL
LEVELS AS WE GET CLOSER TO THE TIME OF THE NEW MOON WILL KEEP THE
POTENTIAL FOR MINOR COASTAL FLOODING OVERALL TO LOCALLY MODERATE
COASTAL FLOODING FOR BAY LOCATIONS.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS EVENING FOR CTZ012.
WINTER STORM WARNING UNTIL 6 PM EST THIS EVENING FOR
CTZ005>011.
NY...WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS EVENING FOR
NYZ078>081.
WINTER STORM WARNING UNTIL 1 PM EST THIS AFTERNOON FOR
NYZ067>070.
WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
NYZ072>075-176-178-179.
WINTER STORM WARNING UNTIL 6 PM EST THIS EVENING FOR NYZ071-
177.
NJ...WINTER STORM WARNING UNTIL 1 PM EST THIS AFTERNOON FOR NJZ002-
004-103.
WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
NJZ006-104>108.
MARINE...GALE WARNING UNTIL 6 AM EST SATURDAY FOR ANZ330-335-338-340-
345-350-353-355.
&&
$$
SYNOPSIS...SEARS/NV
NEAR TERM...GOODMAN/NV
SHORT TERM...NV
LONG TERM...JC/SEARS
AVIATION...GC/JM
MARINE...SEARS/NV
HYDROLOGY...SEARS/NV
TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS NEW YORK NY
949 AM EST FRI MAR 8 2013
.SYNOPSIS...
DEEP LOW PRESSURE REMAINS NEARLY STATIONARY WELL TO THE SOUTHEAST
THROUGH TODAY...THEN SLIDES SOUTHEAST TONIGHT. HIGH PRESSURE
BUILDS OVER THE REGION FOR THE WEEKEND INTO MONDAY. MULTIPLE LOW
PRESSURE SYSTEMS IMPACT THE NORTHEAST THROUGH MID WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
MONITORING BAND OF MODERATE TO HEAVY SNOW THAT HAS DESCENDED UPON
MOST OF THE STATE OF CT FROM THE NORTHEAST. LATEST HRRR INDICATES
THIS BAND SHOULD CONTINUE TO DESCEND INTO COASTAL CT AND
EVENTUALLY LONG ISLAND AS THE DAY PROGRESSES. UPGRADED SRN
WESTCHESTER AND NORTHERN NASSAU...AS WELL AS MOST OF COASTAL
CT...TO WINTER STORM WARNINGS WHERE SPOTTER REPORTS INDICATED 6-8
INCHES OF ACCUMULATION...WITH MORE TO FOLLOW WITH THE
AFOREMENTIONED BAND INTO THIS AFTERNOON. ALSO SEEING SOME SPOTTY 6
INCH TOTALS ACROSS PARTS OF NW SUFFOLK COUNTY...SNOW THERE HAS
LIGHTENED UP FOR THE TIME BEING...BUT AN ADDITIONAL 1-3 INCHES OF
ACCUMULATION MAY BE POSSIBLE WITH THE BAND NOW OVER CT DURING THE
LATE MORNING AND AFTERNOON. WHILE AMTS OVER SUFFOLK SHOULD RANGE
FROM 4-8 INCHES...HAVE NOT UPGRADED TO A WARNING THERE MAINLY DUE
TO THE RELATIVELY LONG DURATION OF SNOWFALL.
ELSEWHERE...WARNINGS/ADVISORIES THAT WERE ALREADY IN EFFECT WERE
EXTENDED A LITTLE LONGER INTO EARLY AFTERNOON ACROSS NYC METRO
AND NE NJ...AND WERE EXTENDED INTO THE AFTERNOON FARTHER EAST.
GUSTY NORTHERLY WINDS WILL PICK UP THROUGH THE DAY...WITH WINDS OF
20 TO 30 MPH AND GUSTS 35 TO 45 MPH. THERE IS A LOW PROBABILITY OF
WIND ADVISORY WINDS.
WITH CLOUDS AND PRECIP TEMPS WILL RUN SEVERAL DEGREES BELOW AVG...
AROUND 40 IN NYC METRO...AND MID/UPPER 30S ELSEWHERE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...
STACKED LOW PRESSURE GRADUALLY DRIFTS FARTHER OFFSHORE TONIGHT WITH
RIDGING SURFACE/ALOFT GRADUALLY BUILDING TOWARDS THE REGION. THIS
WILL ALLOW FOR A GRADUAL SUBSIDING OF WINDS AND CLEARING SKIES.
RIDGING CONTINUES TO BUILDS INTO THE REGION ON SATURDAY...WITH GUSTY
NORTHERLY WINDS IN THE MORNING GRADUALLY RELAXING THROUGH THE
AFTERNOON. OTHERWISE...MOSTLY SUNNY SKIES AND SLIGHTLY ABOVE
SEASONABLE TEMPS EXPECTED IN A MODERATING AIR MASS.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
GENERALLY DECENT MODEL AGREEMENT FOR THE WEEKEND AND INTO THE
BEGINNING OF THE COMING WEEK. SOME MODEL DIVERGENCE ON THE HANDLING
OF THE FIRST LOW PRESSURE SYSTEM AND ACCOMPANYING COLD FRONT LATER
MONDAY AND THE DEVELOPMENT OF A SECONDARY LOW INTO TUESDAY.
SURFACE HIGH PRESSURE EXTENDS DOWN ACROSS THE EASTERN SEABOARD SAT
NIGHT INTO SUNDAY WHILE AN UPPER LEVEL RIDGE SETS UP OVERHEAD BY
SUNDAY. THIS WILL PRODUCE QUIET CONDITIONS...WITH A LIGHT FLOW AND
PARTLY CLOUDY SKIES. WARM AIR ADVECTION INCREASES SUNDAY AS THE HIGH
PUSHES TO THE EAST...SHIFTING WINDS TO THE SOUTHEAST. AS A
RESULT...HIGH TEMPS ON SUNDAY WILL PUSH INTO THE UPPER 40S TO LOWER
50S...A FEW DEGREES ABOVE NORMAL.
A LOW PRESSURE SYSTEM MOVING THROUGH SOUTHERN CANADA WILL APPROACH
WITH A COLD FRONT MONDAY. STRONG SOUTHERLY FLOW AHEAD OF THIS FRONT
WILL KEEP INCREASING THE WAA...WITH HIGH TEMPS ON MONDAY HITTING THE
UPPER 50S AROUND THE NYC METRO AREA...AND LOWER 50S ELSEWHERE. A
WEAK SHORTWAVE MOVING THROUGH MONDAY MORNING COULD BRING A SLIGHT
CHC OF RAIN. CAPPED POPS OFF AT HIGHER END CHC FOR MONDAY AFTN INTO
TUES WITH SOME MODEL DISCREPANCIES ON THE HANDLING OF THE FRONT AND
A DEVELOPING LOW OVER THE TENNESSEE VALLEY REGION AT THE END OF THE
FRONT. THE MODELS GENERALLY AGREE THAT THE COLD FRONT DOES NOT
ACTUALLY PUSH THROUGH THE TRI STATE AREA. BUT THE 00Z ECMWF IS MUCH
MORE PROGRESSIVE ON THE SECONDARY LOW MOVING THROUGH THE EASTERN
GREAT LAKES REGION MONDAY NIGHT...AND THEN DRAGGING A COLD
FRONT/TROUGH THROUGH TUESDAY...WHILE THE 00Z GFS IS FURTHER TO THE
EAST WITH THE CENTER DIRECTLY OVER THE TRI STATE REGION AND A GOOD
12 HOURS SLOWER. SO WHILE THE TIMING OF THE PCPN IS STILL TO BE
DETERMINED...HIGHER CONFIDENCE THAT THE TRACK OF EITHER SOLUTION
WOULD KEEP ANY PCPN AS RAIN OVER THE ENTIRE AREA THROUGH TUESDAY.
MODELS CONTINUE TO DIVERGE MIDWEEK WITH THE ECMWF DEEPENING AN UPPER
LEVEL CLOSED LOW OVER THE NORTHEAST WHILE THE GFS RETURNS TO ALMOST
A ZONAL FLOW WITH HIGH PRESSURE AT THE SURFACE. WITH THE 00Z MODEL
RUNS TRENDING MUCH DIFFERENT THAN PREVIOUS RUNS...AND WITH SUCH
DIFFERENCES BETWEEN THEMSELVES EVEN...WILL NOT MAKE MANY CHANGES FOR
THE LATTER PART OF THE PERIOD. SLIGHT CHC POPS REMAIN IN THE
FORECAST FOR WED INTO THURS TO ACCOUNT FOR A DEVELOPING TROUGH OVER
NEW ENGLAND. WEAK COLD AIR ADVECTION WILL BE SLOW TO MOVE INTO THE
REGION...SO TEMPS REMAIN NEAR TO SLIGHTLY ABOVE NORMAL FOR MID WEEK.
WITH TEMPS GRADUALLY DECREASING...SHOULD SEE AT LEAST MIXED
PCPN...WITH POSSIBLY ALL SNOW WED NIGHT.
&&
.AVIATION /15Z FRIDAY THROUGH TUESDAY/...
LOWER CONFIDENCE IN TIMING THE END OF SNOW FROM EAST TO WEST ASSOCIATED
WITH LOWER CIGS AND VSBY...
WIDESPREAD MVFR CIGS AND MVFR VSBY WILL CONT UNTIL 15Z-18Z AS SNOW MOVES
WEST ACROSS THE REGION.
BANDS OF MODERATE SNOW WILL TEMPORARILY REDUCE CIGS TO IFR AND VSBY
TO LIFR UNTIL 16Z FROM THE NYC METRO AREA EAST INCLUDING AT KJFK AND
KLGA.
CIGS AND VSBY WILL GRADUALLY IMPROVE AFT 18Z...BECOMING VFR BY 21Z.
HIGH CONFIDENCE IN WIND FORECAST...
N TO NW WINDS FROM 330-350 DEG WILL GRADUALLY INCREASE AND PEAK FROM
15Z TO 21Z...REACHING SUSTAINED SPEEDS OF 20-25 KT FROM NYC EAST WITH
GUSTS OF 30-34 KT. WEST OF NYC INCLUDING KEWR...SUSTAINED WINDS WILL
INCREASE TO 15-20 KT WITH GUSTS OF 25-30 KT.
N TO NW WINDS WILL GRADUALLY DECREASE AFT SUNSET BECOMING 10-15 KT
WITH GUSTS OF 20-25 KT.
NY METRO ENHANCED AVIATION WEATHER SUPPORT...
DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN
BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)
KEWR FCSTER COMMENTS: TIMING THE END OF SNOW WITH LOWER CIGS AND
VSBY COULD BE OFF BY A FEW HOURS.
THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH IMPLIES
SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD.
KJFK FCSTER COMMENTS: TIMING THE END OF SNOW WITH LOWER CIGS AND
VSBY COULD BE OFF BY A FEW HOURS.
KLGA FCSTER COMMENTS: TIMING THE END OF SNOW WITH LOWER CIGS AND
VSBY COULD BE OFF BY A FEW HOURS.
KTEB FCSTER COMMENTS: TIMING THE END OF SNOW WITH LOWER CIGS AND
VSBY COULD BE OFF BY A FEW HOURS.
KHPN FCSTER COMMENTS: TIMING THE END OF SNOW WITH LOWER CIGS AND
VSBY COULD BE OFF BY A FEW HOURS.
KISP FCSTER COMMENTS: TIMING THE END OF SNOW WITH LOWER CIGS AND
VSBY COULD BE OFF BY A FEW HOURS.
OUTLOOK FOR 06Z SATURDAY THROUGH WEDNESDAY...
.TONIGHT...VFR WITH DECREASING NORTH WINDS.
.SAT-SUN...VFR.
.MON...VFR...INCREASING S WINDS LATE IN THE DAY.
.TUE...COLD FRONTAL PASSAGE WITH RAIN SHOWERS. SUB-VFR CONDITIONS
EXPECTED.
.WED...VFR.
&&
.MARINE...
GALES EXPECTED ON ALL WATERS TODAY AS THE PRESSURE GRADIENT
SLIGHTLY TIGHTENS BETWEEN STATIONARY OFFSHORE LOW PRESSURE AND
HIGH PRESSURE BUILDING INTO WESTERN NY. GALES SHOULD THEN
GRADUALLY SUBSIDE TO SCA FROM W TO E THIS EVENING...AND THEN
GRADUALLY FALLING BELOW SCA ON SAT. LONG PERIOD EASTERLY SWELLS
WILL LIKELY KEEP SEAS HIGH ON THE OCEAN INTO SAT...10-15 FT.
SEAS ON THE OCEAN WILL REMAIN ELEVATED AROUND 5 FT SAT NIGHT INTO
SUNDAY...GRADUALLY DIMINISHING AS THE WINDS DECREASE WITH HIGH
PRESSURE BUILDS IN. A BRIEF PERIOD OF SUB-SCA CONDITIONS IS EXPECTED
MONDAY BEFORE WINDS AND SEAS INCREASE ONCE AGAIN WITH THE NEXT LOW
PRESSURE SYSTEM TO SCA LEVELS. DEPENDING ON THE TRACK OF THE LOW
MIDWEEK...THERE MAY BE A CHANCE OF GALES ON THE OCEAN WATERS. BUT
VERY LOW CONFIDENCE AT THIS TIME OF OCCURRING.
&&
.HYDROLOGY...
TOTAL LIQUID EQUIVALENT QPF TONIGHT THROUGH FRI IS FORECAST TO
RANGE FROM AROUND ONE THIRD TO THREE QUARTERS OF AN INCH.
HYDRO RELATED ISSUES ARE NOT ANTICIPATED AT THIS TIME.
DRY WEATHER FOR THE WEEKEND...THEN LIGHT TO MODERATE PRECIPITATION
AMOUNTS WILL BE POSSIBLE MONDAY NIGHT INTO TUESDAY.
&&
.TIDES/COASTAL FLOODING...
RESIDUAL SURGE OF 1 1/2 TO 2 1/2 FT WILL RESULT IN WIDESPREAD
MINOR COASTAL FLOODING EXPECTED WITH THIS MORNING HIGH TIDES
ACROSS THE ENTIRE COAST.
FOR THE LOWER HIGH TIDE THIS AFT/EVE WATER LEVELS WILL LIKELY ONLY
TOUCH MINOR LEVELS ACROSS THE SOUTH SHORE BAYS OF LI...TWIN FORKS
AND WESTERN AND CENTRAL LI SOUND...INCLUDING THE NORTH SHORE OF LI.
MODERATE BEACH EROSION ISSUES WILL CONTINUE INTO SATURDAY FOR
OCEAN FACING BEACHES AND TWIN FORKS OF LI WITH BREAKERS BETWEEN 7
TO 11 FT...HIGHEST EAST OF MORICHES INLET.
LOOKING TOWARDS THE WEEKEND...FURTHER INCREASES IN ASTRONOMICAL
LEVELS AS WE GET CLOSER TO THE TIME OF THE NEW MOON WILL KEEP THE
POTENTIAL FOR MINOR COASTAL FLOODING OVERALL TO LOCALLY MODERATE
COASTAL FLOODING FOR BAY LOCATIONS.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS EVENING FOR CTZ012.
COASTAL FLOOD ADVISORY UNTIL 11 AM EST THIS MORNING FOR
CTZ009>012.
WINTER STORM WARNING UNTIL 6 PM EST THIS EVENING FOR
CTZ005>011.
NY...WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS EVENING FOR
NYZ078>081.
COASTAL FLOOD ADVISORY UNTIL 11 AM EST THIS MORNING FOR NYZ071-
073-078-079-081-176-177.
WINTER STORM WARNING UNTIL 1 PM EST THIS AFTERNOON FOR
NYZ067>070.
WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
NYZ072>075-176-178-179.
WINTER STORM WARNING UNTIL 6 PM EST THIS EVENING FOR NYZ071-
177.
COASTAL FLOOD ADVISORY UNTIL 10 AM EST THIS MORNING FOR NYZ080-
179.
NJ...WINTER STORM WARNING UNTIL 1 PM EST THIS AFTERNOON FOR NJZ002-
004-103.
WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
NJZ006-104>108.
MARINE...GALE WARNING UNTIL 6 AM EST SATURDAY FOR ANZ330-335-338-340-
345-350-353-355.
&&
$$
SYNOPSIS...SEARS/NV
NEAR TERM...GOODMAN
SHORT TERM...NV
LONG TERM...JC/SEARS
AVIATION...GC
MARINE...SEARS/NV
HYDROLOGY...SEARS/NV
TIDES/COASTAL FLOODING...SEARS
AREA FORECAST DISCUSSION
NWS TOPEKA KS
527 AM CST FRI MAR 8 2013
...UPDATE TO AVIATION...
.DISCUSSION...
SHORT RANGE FORECAST (TODAY THROUGH SATURDAY)...
09Z RAP ANALYSIS AND SURFACE OBS SHOW A TIGHTENING SURFACE PRESSURE
GRADIENT TAKING FORM ACROSS THE AREA AS AN AREA OF LOW PRESSURE SITS
OVER SE COLORADO. WATER VAPOR IMAGERY INDICATES THAT A MID TO UPPER
LEVEL TROUGH CURRENTLY SITS OVER SOUTHERN CALIFORNIA...WITH A STRONG
SOUTH/SOUTHWEST COMPONENT TO THE MID/UPPER WINDS WELL TO THE EAST OF
THE TROUGH CENTER. WITHIN THIS MID LEVEL SOUTHERLY FLOW WATER VAPOR
IMAGERY SHOWS SOME MOISTURE WORKING ITS WAY THROUGH THE SOUTHERN
HIGH PLAINS INTO WESTERN KANSAS. THIS TROUGH WILL BE THE IMPETUS
BEHIND RAIN CHANCES LATER TONIGHT THROUGH THE WEEKEND. AS THE
SURFACE TROUGH TAKES FORM THE SURFACE PRESSURE GRADIENT WILL BECOME
A BIT STRONGER ALLOWING FOR THE WINDS TO PICK UP THROUGHOUT THE DAY.
EXPECT S/SE WINDS TO EVENTUALLY INCREASE TO BETWEEN 15 AND 25
MPH...WITH GUSTS UP TO 30. LOW LEVEL SOUTHERLY WINDS WILL ALSO
TRANSPORT WARM/MOIST AIR INTO THE AREA. EXPECT DEWPOINTS TO INCREASE
THROUGHOUT THE DAY TO THE MID 40S BY LATE TONIGHT. ISENTROPIC CHARTS
SHOW A STRONG ISENTROPIC COMPONENT WITHIN THE S/SE LOW AND MID LEVEL
WINDS WHICH MAY LEAD TO INCREASING CLOUDS THROUGH THE AFTERNOON
HOURS...HOWEVER CONDENSATION PRESSURE DEFICITS LOOK TO REMAIN TOO
HIGH TO PRODUCE ANY PRECIPITATION UNTIL LATER THIS EVENING. WITH THE
MAIN AREA OF MID LEVEL ENERGY HANGING OFF TO THE WEST THE MAIN
INFLUENCE FOR FRIDAY NIGHT PRECIP WILL BE THE STRONG ISENTROPIC
COMPONENT. FORECAST SOUNDING CORROBORATE WHAT THE ISENTROPIC
SURFACES SUGGEST...WHICH IS THAT THE COLUMN WILL HAVE SOME DRY AIR
TO OVERCOME THROUGHOUT THE DAY ON FRIDAY. EVENTUALLY IT WILL
OVERCOME THE DRY AIR AND PRECIP WILL BEGIN FRIDAY EVENING. PRECIP
COVERAGE AND INTENSITY WILL INCREASE THROUGH THE NIGHT AS THE COLUMN
BECOMES COMPLETELY SATURATED.
BY LATE FRIDAY NIGHT INTO EARLY SATURDAY MORNING THE MID LEVEL
TROUGH WILL BEGIN MOVING THROUGH THE AREA. THE EXTRA LARGE SCALE
ASCENT SHOULD ALLOW FOR MORE EFFICIENT RAIN PROCESSES...CAUSING
PERIODS OF MODERATE RAIN TO OCCUR THROUGH MID DAY ON SATURDAY. ALONG
WITH THE BETTER LARGE SCALE ASCENT THE COOLER TEMPS ALOFT ASSOCIATED
WITH THE LARGE TROUGH WILL ALLOW FOR SOME ELEVATED STEEP LAPSE
RATES...MAKING ELEVATED CAPE LEVELS APPROACH 500 J/KG. AS A RESULT
PERIODS OF THUNDERSTORMS WILL BE LIKELY LATE FRIDAY NIGHT THROUGH
THE DAY ON SATURDAY. ALTHOUGH THE THUNDERSTORMS ARE NOT EXPECTED TO
BE VIGOROUS THE MODEST CAPE ALONG WITH 40 TO 50 KTS OF 0-6 SHEAR IT
IS POSSIBLE THAT AN ISOLATED CELL OR TWO COULD BECOME STRONG WITH
PERHAPS A SEVERE HAIL REPORT OR TWO SATURDAY MORNING/AFTERNOON.
AS THE SYSTEM PROGRESSES TO THE EAST MODELS SEEM TO AGREE ON THE
PLACEMENT AND TIMING OF A DRY SLOT OF MID LEVEL AIR CUTTING OFF THE
EFFICIENT PRECIP PROCESSES BY SATURDAY AFTERNOON/EVENING. THIS WILL
LIKELY SPELL AN END TO THE MODERATE PRECIP...ALTHOUGH SOME LIGHT
PRECIP MAY LINGER THROUGH LATE SATURDAY NIGHT. ACROSS THE NORTHERN
COUNTIES THERE WILL REMAIN A CHANCE FOR SOME VERY LIGHT SNOW FALL
SATURDAY NIGHT AS A WEAK TROWAL FORMS ACROSS CENTRAL NEBRASKA. GIVEN
THAT THE REGION WILL EXPERIENCE SEVERAL DAYS IN A ROW OF ABOVE
FREEZING TEMPERATURES AS WELL AS A WET GROUND FROM THE SATURDAY
RAINFALL EXPECT SNOW ACCUMULATIONS TO BE TOUGH TO COME BY. PERHAPS A
DUSTING OF SNOW WILL BE POSSIBLE ON GRASSY AND ELEVATED
SURFACES...BUT EXPECT PAVED SURFACES TO STAY WET AS OPPOSED TO SNOW
PACKED. BY SUNDAY AFTERNOON THE SYSTEM SHOULD MOVE OFF TO THE EAST
ENDING ALL PRECIPITATIONS CHANCES.
QPF FORECAST FOR THIS SYSTEM REMAINS A BIT CONSERVATIVE AS MODELS
HAVE OVERDONE PRECIP AMOUNT IN RECENT SYSTEMS. ON THE LOWER END THIS
SYSTEM SHOULD HAVE NO PROBLEM PRODUCING A QUARTER INCH OF
PRECIPITATION AREA-WIDE...WITH PERHAPS A FEW ISOLATED AREAS GETTING
A FULL INCH. MOST AREAS WILL LIKELY GET SOMEWHERE BETWEEN THOSE TWO
VALUES IN LIQUID PRECIP BETWEEN FRIDAY NIGHT AND SUNDAY MORNING.
MID RANGE AND EXTENDED FORECAST (MONDAY THROUGH THURSDAY)...
A STRONG PUSH OF COLD AIR WILL FOLLOW THE SYSTEM THROUGH THE AREA
AND TO THE EAST. THIS PUSH OF COLD AIR WILL LIKELY BRING A COOL DOWN
FOR SUNDAY AND MONDAY BEFORE SOUTHERLY FLOW RECOMMENCES...BRINGING
WARM/MOIST AIR BACK INTO THE AREA. FOR A FEW DAYS NOW MODELS HAVE
SHOWN THAT THE AREA WILL STAY DRY THROUGH NEXT WORK WEEK WITH A
GRADUAL...BUT NOTICEABLE WARM UP. WITH A MID LEVEL RIDGE OFF TO THE
WEST...GRADUALLY CREEPING EASTWARD THROUGH THE WEEK AND MOSTLY
PERSISTENT SOUTHERLY FLOW EXPECT TUESDAY THROUGH THURSDAY TO BRING
ABOVE SEASONALLY NORMAL TEMPERATURES.
JL
&&
.AVIATION...
LLWS CONTINUES EARLY THIS MORNING BEFORE WINDS PICK UP AND MIX OUT
AROUND 14Z. CLOUDS SLOWLY INCREASE AND LOWER THROUGH THE
PERIOD...WITH VICINITY SHRA/TSRA EXPECTED BY LATE AFTERNOON.
PREVAILING TS BEST CHANCE OF MOVING IN AFTER MIDNIGHT. 67
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
413 AM CST FRI MAR 8 2013
.DISCUSSION...
SHORT RANGE FORECAST (TODAY THROUGH SATURDAY)...
09Z RAP ANALYSIS AND SURFACE OBS SHOW A TIGHTENING SURFACE PRESSURE
GRADIENT TAKING FORM ACROSS THE AREA AS AN AREA OF LOW PRESSURE SITS
OVER SE COLORADO. WATER VAPOR IMAGERY INDICATES THAT A MID TO UPPER
LEVEL TROUGH CURRENTLY SITS OVER SOUTHERN CALIFORNIA...WITH A STRONG
SOUTH/SOUTHWEST COMPONENT TO THE MID/UPPER WINDS WELL TO THE EAST OF
THE TROUGH CENTER. WITHIN THIS MID LEVEL SOUTHERLY FLOW WATER VAPOR
IMAGERY SHOWS SOME MOISTURE WORKING ITS WAY THROUGH THE SOUTHERN
HIGH PLAINS INTO WESTERN KANSAS. THIS TROUGH WILL BE THE IMPETUS
BEHIND RAIN CHANCES LATER TONIGHT THROUGH THE WEEKEND. AS THE
SURFACE TROUGH TAKES FORM THE SURFACE PRESSURE GRADIENT WILL BECOME
A BIT STRONGER ALLOWING FOR THE WINDS TO PICK UP THROUGHOUT THE DAY.
EXPECT S/SE WINDS TO EVENTUALLY INCREASE TO BETWEEN 15 AND 25
MPH...WITH GUSTS UP TO 30. LOW LEVEL SOUTHERLY WINDS WILL ALSO
TRANSPORT WARM/MOIST AIR INTO THE AREA. EXPECT DEWPOINTS TO INCREASE
THROUGHOUT THE DAY TO THE MID 40S BY LATE TONIGHT. ISENTROPIC CHARTS
SHOW A STRONG ISENTROPIC COMPONENT WITHIN THE S/SE LOW AND MID LEVEL
WINDS WHICH MAY LEAD TO INCREASING CLOUDS THROUGH THE AFTERNOON
HOURS...HOWEVER CONDENSATION PRESSURE DEFICITS LOOK TO REMAIN TOO
HIGH TO PRODUCE ANY PRECIPITATION UNTIL LATER THIS EVENING. WITH THE
MAIN AREA OF MID LEVEL ENERGY HANGING OFF TO THE WEST THE MAIN
INFLUENCE FOR FRIDAY NIGHT PRECIP WILL BE THE STRONG ISENTROPIC
COMPONENT. FORECAST SOUNDING CORROBORATE WHAT THE ISENTROPIC
SURFACES SUGGEST...WHICH IS THAT THE COLUMN WILL HAVE SOME DRY AIR
TO OVERCOME THROUGHOUT THE DAY ON FRIDAY. EVENTUALLY IT WILL
OVERCOME THE DRY AIR AND PRECIP WILL BEGIN FRIDAY EVENING. PRECIP
COVERAGE AND INTENSITY WILL INCREASE THROUGH THE NIGHT AS THE COLUMN
BECOMES COMPLETELY SATURATED.
BY LATE FRIDAY NIGHT INTO EARLY SATURDAY MORNING THE MID LEVEL
TROUGH WILL BEGIN MOVING THROUGH THE AREA. THE EXTRA LARGE SCALE
ASCENT SHOULD ALLOW FOR MORE EFFICIENT RAIN PROCESSES...CAUSING
PERIODS OF MODERATE RAIN TO OCCUR THROUGH MID DAY ON SATURDAY. ALONG
WITH THE BETTER LARGE SCALE ASCENT THE COOLER TEMPS ALOFT ASSOCIATED
WITH THE LARGE TROUGH WILL ALLOW FOR SOME ELEVATED STEEP LAPSE
RATES...MAKING ELEVATED CAPE LEVELS APPROACH 500 J/KG. AS A RESULT
PERIODS OF THUNDERSTORMS WILL BE LIKELY LATE FRIDAY NIGHT THROUGH
THE DAY ON SATURDAY. ALTHOUGH THE THUNDERSTORMS ARE NOT EXPECTED TO
BE VIGOROUS THE MODEST CAPE ALONG WITH 40 TO 50 KTS OF 0-6 SHEAR IT
IS POSSIBLE THAT AN ISOLATED CELL OR TWO COULD BECOME STRONG WITH
PERHAPS A SEVERE HAIL REPORT OR TWO SATURDAY MORNING/AFTERNOON.
AS THE SYSTEM PROGRESSES TO THE EAST MODELS SEEM TO AGREE ON THE
PLACEMENT AND TIMING OF A DRY SLOT OF MID LEVEL AIR CUTTING OFF THE
EFFICIENT PRECIP PROCESSES BY SATURDAY AFTERNOON/EVENING. THIS WILL
LIKELY SPELL AN END TO THE MODERATE PRECIP...ALTHOUGH SOME LIGHT
PRECIP MAY LINGER THROUGH LATE SATURDAY NIGHT. ACROSS THE NORTHERN
COUNTIES THERE WILL REMAIN A CHANCE FOR SOME VERY LIGHT SNOW FALL
SATURDAY NIGHT AS A WEAK TROWAL FORMS ACROSS CENTRAL NEBRASKA. GIVEN
THAT THE REGION WILL EXPERIENCE SEVERAL DAYS IN A ROW OF ABOVE
FREEZING TEMPERATURES AS WELL AS A WET GROUND FROM THE SATURDAY
RAINFALL EXPECT SNOW ACCUMULATIONS TO BE TOUGH TO COME BY. PERHAPS A
DUSTING OF SNOW WILL BE POSSIBLE ON GRASSY AND ELEVATED
SURFACES...BUT EXPECT PAVED SURFACES TO STAY WET AS OPPOSED TO SNOW
PACKED. BY SUNDAY AFTERNOON THE SYSTEM SHOULD MOVE OFF TO THE EAST
ENDING ALL PRECIPITATIONS CHANCES.
QPF FORECAST FOR THIS SYSTEM REMAINS A BIT CONSERVATIVE AS MODELS
HAVE OVERDONE PRECIP AMOUNT IN RECENT SYSTEMS. ON THE LOWER END THIS
SYSTEM SHOULD HAVE NO PROBLEM PRODUCING A QUARTER INCH OF
PRECIPITATION AREA-WIDE...WITH PERHAPS A FEW ISOLATED AREAS GETTING
A FULL INCH. MOST AREAS WILL LIKELY GET SOMEWHERE BETWEEN THOSE TWO
VALUES IN LIQUID PRECIP BETWEEN FRIDAY NIGHT AND SUNDAY MORNING.
MID RANGE AND EXTENDED FORECAST (MONDAY THROUGH THURSDAY)...
A STRONG PUSH OF COLD AIR WILL FOLLOW THE SYSTEM THROUGH THE AREA
AND TO THE EAST. THIS PUSH OF COLD AIR WILL LIKELY BRING A COOL DOWN
FOR SUNDAY AND MONDAY BEFORE SOUTHERLY FLOW RECOMMENCES...BRINGING
WARM/MOIST AIR BACK INTO THE AREA. FOR A FEW DAYS NOW MODELS HAVE
SHOWN THAT THE AREA WILL STAY DRY THROUGH NEXT WORK WEEK WITH A
GRADUAL...BUT NOTICEABLE WARM UP. WITH A MID LEVEL RIDGE OFF TO THE
WEST...GRADUALLY CREEPING EASTWARD THROUGH THE WEEK AND MOSTLY
PERSISTENT SOUTHERLY FLOW EXPECT TUESDAY THROUGH THURSDAY TO BRING
ABOVE SEASONALLY NORMAL TEMPERATURES.
JL
&&
.AVIATION...
STILL SOME OPPORTUNITY FOR LIMITING CEILINGS LATER IN THIS
FORECAST...BUT APPEARS TOP AND FOE SHOULD HOLD OFF UNTIL AFTER
06Z. ENOUGH WINDS SAMPLED BY RADARS AND PROFILERS TO SUPPORT LLWS
MENTION TO START THIS FORECAST. CHANCES FOR SHRA INCREASE AT THE
END OF THE FORECAST.
65
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BISMARCK ND
854 AM CST FRI MAR 8 2013
.DISCUSSION...LATST BOWMAN RADAR SHOWS AN AREA OF PRECIPITATION
APPROACHING FROM THE SOUTH. THE LATEST RAP CAPTURES THIS AREA AND
PUSHES IT ACROSS THE SOUTHWEST FROM 15Z THROUGH MID AFTERNOON.
HAVE INCREASED POPS TO LIKELY IN THIS AREA.
DENSE FOG FROM JAMESTOWN TO OAKES THIS MORNING SHOULD CONTINUE TO
ERODE QUICKLY THIS MORNING AS THE JAMESTOWN WEB CAMS SEEM TO BE
IMPROVING. WILL HOLD OFF ON ANY ADVISORY FOR NOW UNLESS CONDITIONS
APPEAR TO LINGER LONGER THAN EXPECTED.
OTHER CONCERN FOR THE SHORT TERM PERIOD WILL BE THE FAR SOUTHEAST
COUNTIES TONIGHT AND SATURDAY...AS AN UPPER LOW NOW OVER SOUTHERN
CALIFORNIA EJECTS NORTHEAST WITH ITS ATTENDANT PRECIPITATION. WILL
LOOK MORE INTO THIS WITH THE 12Z DATA.
&&
.AVIATION...DENSE FOG/VLIFR VSBYS AT KJMS WILL GRADUALLY LIFT TO
MVFR VSBYS BY MID TO LATE MORNING...THEN VFR THIS AFTERNOON.
OTHERWISE...EXPECT MAINLY MID LEVEL CLOUDS SCATTERED MVFR VSBYS
THIS MORNING. WINDS WILL GENERALLY BECOME LIGHT AND VARIABLE AS
HIGH PRESSURE BUILDS INTO THE REGION. AN APPROACHING DISTURBANCE
WILL GENERATE A CHANCE FOR PRECIPITATION MAINLY SOUTH LATE THIS
AFTERNOON AND EVENING...WITH CHANCES TO THE NORTH LATER TONIGHT.
MVFR CIGS AND/OR VSBYS ARE LIKELY AGAIN TONIGHT.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
DISCUSSION/AVIATION...KS/RK
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
859 AM MST FRI MAR 8 2013
.UPDATE...
ISSUED AT 853 AM MST FRI MAR 8 2013
15Z SURFACE ANALYSIS HAD A WEAK COLD FRONT ACROSS MT INTO SOUTHERN
ND. WATER VAPOUR HAD LARGE UPPER TROUGH WITH UPPER LOW DIGGING
INTO SOUTHERN CA. SOUTHWEST FLOW ALOFT AHEAD OF SYSTEM PRODUCING
STREAM OF MID/HIGH CLOUDS OVER THE CWA. EMBEDDED SHORTWAVE OVER
SOUTHEAST MT...UNDER RIGHT ENTRANCE REGION OF 90KT JET...PRODUCING
SOME WEAK RADAR RETURNS OVER NORTHWEST SD. AREA ALSO IN A REGION OF
WEAK LOW LEVEL FRONTOGENESIS...WHICH SHOULD PERSIST MOST OF THE
DAY PER 12Z RAP AND THUS WILL CONTINUE LOW POPS IN FAR NORTHWEST
PORTIONS OF CWA. PRESSURE FALLS OVER EASTERN WY/MT SUPPORTING
EAST/SOUTHEAST LOW LEVEL FLOW AND SOME FOG OVER PORTIONS OF
CENTRAL SD. FOG SHOULD MIX AWAY SOME BY EARLY AFTERNOON...SO HAVE
EXPANDED AND EXTENDED CURRENT AREA OF FOG TO COVER SOUTHEAST
THIRD OF THE CWA.
FINALLY...12Z NAM CONTINUES TREND OF FASTER NORTHERN STREAM
TROUGH...WHICH WILL PUSH CA TROUGH FURTHER SOUTH AND EAST OF CWA.
HAVE ADJUSTED POPS TO MATCH SLOWER ONSET OF PRECIPITATION THIS
EVENING.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY NIGHT)
ISSUED AT 351 AM MST FRI MAR 8 2013
DIGGING SW CONUS UPPER TROUGH WILL EJECT TOWARD THE
REGION IN THE PERIOD AND SUPPORT CYCLOGENESIS OVER THE CENTRAL PLAINS.
MEANWHILE A FAST MOVING NORTHERN STREAM TROUGH WILL DROP INTO THE
NORTHERN PLAINS JUST AHEAD OF THE SW CONUS TROUGH...EVENTUALLY
PHASING EAST OF THE REGION. FORECAST MODELS HAVE STRUGGLED WITH
FORECAST DETAILS FOR THE LAST SEVERAL RUNS...KEEPING THE TRACK WELL
SOUTH OF THE FA AT FIRST/THEN SHIFTING THE TRACK NW FOR SEVERAL
CYCLES /WITH THE LATEST SUITE SUPPORTING A SHIFT BACK TO THE SOUTH.
THE EXACT TRACK WILL HINGE UPON TWO MAIN FEATURES: 1/ HOW FAST THE
NORTHERN STREAM TROUGH PROPAGATES INTO THE NORTHERN PLAINS AHEAD OF
THE EJECTING SW CONUS UPPER TROUGH. 2/ THE INTENSITY OF THE FORWARD
FLANK JET STREAK WHICH WILL DETERMINE THE DEGREE OF POSITIVE TROUGH
TILT AND ASSOCIATED SHEARING OF THE THE SW CONUS UPPER WAVE...HIGHLY
AFFECTING THE SPEED AND LIFT PLACEMENT. CURRENT TRENDS SUPPORT A
STRONGER POSITIVE TILT TO THE SW CONUS UPPER WAVE...WITH A
ASSOCIATED FASTER PROPAGATION SPEED...BRINGING IN A VERSION OF
STRONGER SUBSIDENCE...WITH ASSOCIATED LL DRYING OVER MUCH OF THE
WESTERN 2/3 OF THE FA SAT. IN ADDITION..LL THERMAL FIELDS HAVE
TRENDED SLIGHTLY WARMER IN THE LATEST CONSENSUS BLEND...WITH MANY
LOCATIONS EXPECTED TO BE WELL IN THE 30S AND EVEN LOWER 40S ON
SAT...SAVE FAR SOUTH CENTRAL WHERE THE STRONGER COLLOCATION OF DEEP
LAYER LIFT WILL BE PRESENT. THE POTENTIAL FOR MIXED PRECIP WITH A
PERIOD OF FREEZING RAIN EXISTS OVER SCENTRAL LATE TONIGHT INTO SAT
MORNING...ALTHOUGH AS STATED EARLIER...FORECAST MODELS HAVE TERNED
WARMER PER THERMAL FIELDS...WITH LOCATIONS INVOF ICR REMAINING ABOVE
FREEZING UNTIL SAT MORNING. ACCUMULATING SNOWFALL LOOKS TO REMAIN
CONFINED TO THE FAR SOUTH AND SCENTRAL FA...WITH STRONG INDICATIONS
REMAIN FOR POTENTIAL DEFORMATION BANDING OVER FAR SCENTRAL SAT
AFTERNOON...A SOLUTION INDICATED IN NAM/GFS/SREF/AND ECMWF
SOLUTIONS. QUESTION REMAINS THROUGH WHERE AND THIS BAND WILL SETUP
AND THE DEGREE OF LL MOISTURE IN PLACE WHEN THE STRONGEST ROUND OF
DEEP ASCENT DEVELOPS IN THAT LOCATION.
LINGERING WEAK WAA/DEFORMATION ZONE WILL CONTINUE TO SHIFT NORTH OUT OF
THE FA THIS MORNING...WITH ONLY SMALL CHANCES FOR PRECIP GIVEN WEAK
FORCING AND DRY LL/S. OTHERWISE...THE NEXT ROUND OF STRONG WAA WILL
ENSUE THIS EVENING OVER SOUTHERN PORTIONS OF THE FA...SPREADING
NORTH OVERNIGHT. IT IS ENTIRELY POSSIBLE THAT THE MAJORITY OF PRECIP
MAY BE CONFINED TO THE FAR SE PORTION OF THE FA...WITH MUCH
UNCERTAINTY REMAINING PER THE DETAILS OF THE THIS FIRST ROUND OF WAA.
RETAINED A MIXED POTENTIAL FOR THIS IN SE...WITH GENERAL RAIN
CHANGING TO SNOW CHANCES ELSEWHERE. NORTHERN STREAM TROUGH WILL DIVE
IN THE NORTHERN PLAINS AND SUPPORT A ROUND OF LARGE SCALE SINK OVER
MUCH OF THE FA SAT...SUPPORTING LL DRYING OVER MUCH OF THE FA. DID
TREND POPS DOWN AND TO THE SOUTH GIVEN THIS CONCERN.
OTHERWISE...INCREASING LARGE SCALE ASCENT INDICATED IN Q-VECTOR
PROGS IS EXPECTED OVER THE SOUTHERN PORTIONS OF THE FA...MAINLY
SOUTH AND EAST OF A PINE RIDGE TO KADOKA LINE LATE SAT MORNING.
ASSOCIATED LIFT MAY CONTINUE TO SUPPORT MIXED PRECIP.
HOWEVER...DEEP AND STRONG ASCENT WILL LIKELY SUPPORT ENOUGH DYNAMIC
COOLING TO SUPPORT ALL SNOW OVER SCENTRAL AREAS BY MID MORNING.
OTHERWISE...THE REMAINDER THE FA MAY NOT SEE MUCH IN THE WAY OF
PRECIP GIVEN STRONG SINK AND DRYING LL/S. THIS INCLUDES THE NORTHERN
HILLS WHERE MOISTURE LOOKS TO BE LIMITED. THE NAM CERTAINLY DISPLAYS
A SHARP CUT OFF TO PRECIP IN QPF PROGS WHICH LOOKS HIGHLY CREDIBLE.
A RATHER WARM BL MAY LIMIT ACCUMS OVER PORTIONS OF THE SOUTHERN
FA...HOWEVER THE POTENTIAL FOR UP TO 4 INCHES REMAIN OVER THE FAR
SE...MELLETTE/TODD/TRIPP COUNTIES...WITH A LIKELY HEAVY WET LOWER
RATIO SNOW BEING FAVORED. TRIED TO INCORPORATED A SHIFT OF THE
HIGHEST POPS SE...LOWERING THE NW. WILL CONTINUE THE SPS AS DETAILS
ARE STILL LACKING AND WARNING CRITERIA NOT EXPECTED. STRONG GUSTY NW
WINDS ARE ALSO EXPECTED SAT AFTERNOON...ESP ON THE EASTERN BH
FOOTHILLS. HOWEVER...WARM BL TEMPS ABOVE FREEZING MAY HIGHLY LIMIT
BLOWING SNOW POTENTIAL. UPPER TROUGH AND ASSOCIATED LIFT WILL
QUICKLY SHIFT EAST AND WANE OVER THE FA SAT EVENING...WITH ALL
PLACES DRY AFTER MIDNIGHT.
.LONG TERM...(SUNDAY THROUGH THURSDAY)
ISSUED AT 351 AM MST FRI MAR 8 2013
TEMPERATURES WILL GRADUALLY WARM INTO EARLY NEXT WEEK AS RIDGE
BUILDS OVER THE WESTERN CONUS. A VARIETY OF WEAK DISTURBANCES MOVING
THROUGH WILL BRING LOW PRECIP CHANCES TO PTNS OF THE AREA THROUGH
THE FIRST PART OF THE WEEK. RIDGE CONTINUES TO AMPLIFY OVER THE AREA
FOR THE LAST PART OF THE WORK WEEK BRINGING DRY CONDITIONS AND WARM
TEMPS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 351 AM MST FRI MAR 8 2013
ISOLD RAIN OR SNOW SHOWERS MAY LINGER OVER NORTHEAST WYOMING INTO
NORTHWEST SOUTH DAKOTA TODAY BRINGING LCL MVFR CIGS/VIS. FOR
TONIGHT...RAIN TRANSITIONING TO SNOW WILL DEVELOP OVER THE
AREA...WITH THE GREATEST CHANCES OVER SOUTH CENTRAL SOUTH DAKOTA
WHERE SOME FREEZING RAIN MAY ALSO DEVELOP. WIDESPREAD IFR CIGS WITH
AREAS OF IFR VIS ARE EXPECTED OVER MUCH OF THE AREA.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&
$$
UPDATE...HELGESON
SHORT TERM...JC
LONG TERM...77
AVIATION...77
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
549 AM CST FRI MAR 8 2013
.AVIATION...
CHALLENGES FOR THE 12Z TAF SET INCLUDE CIG TRENDS BETWEEN MVFR AND
LOW VFR AND TIMING OF RAIN CHANCES WITH A LEAD DISTURBANCE THIS
AFTERNOON.
STRATO-CU IN THE MVFR/VERY LOW VFR RANGE HAS BEEN SURGING NORTH
ACROSS THE TERMINALS IN ADVANCE OF A LEAD SHORTWAVE DISTURBANCE
ROTATING NORTHEAST OUT OF OLD MEXICO AND THE RIO GRANDE VALLEY.
THOUGH THERE MAY BE A BRIEF WINDOW FOR LOW VFR CIGS BETWEEN
030-040 THIS MORNING...WILL LEAN WITH MODEL BUFR AND RUC OPS40
SOUNDINGS WITH GOING WITH A PREVAILING MVFR AROUND 025...BUT WITH
A TEMPO GROUP FOR LOW MVFR CIGS BETWEEN 015-020 THROUGH LATE
MORNING.
ISENTROPIC ASCENT THIS AFTERNOON SHOULD HELP TOP-DOWN COLUMN
SATURATION OCCUR QUICKLY AND SOME -RA/-SHRA OCCURRING BETWEEN 21Z
AND 01Z. HAVE INTRODUCED A PROB30 GROUP TO COVER THIS VERY LIGHT
RAINFALL THAT IS EXPECTED THIS AFTERNOON. THE LEAD SHORTWAVE EXITS
TO THE NORTHEAST EARLY THIS EVENING WITH A BRIEF WINDOW FOR CIGS
IMPROVING TO LOW VFR ONCE AGAIN...BEFORE RETURNING TO THE MVFR
CATEGORY BY MIDNIGHT AND BEYOND. SOUTHEAST WINDS 10-15 KTS WILL
CONTINUE THROUGHOUT THE FORECAST.
OUTLOOK...
MODELS HAVE SPED UP TIMING OF DRYLINE/FRONT IN ADVANCE OF OUR MAIN
SYSTEM ROTATING SOUTHEAST CURRENTLY OVER SRN CA/WRN AZ. IT APPEARS
THE MAIN WINDOW FOR +TSRA WILL BE 21Z-03Z SATURDAY WITH WINDS SHIFTING
NORTHWEST AND VERY GUSTY BEHIND THE COLD FRONT BY 12Z SUNDAY.
05/
&&
.PREV DISCUSSION... /ISSUED 313 AM CST FRI MAR 8 2013/
0UR NEXT UPPER STORM SYSTEM WILL BE MOVING INTO SOUTHERN CALIFORNIA
THIS MORNING WITH CYCLOGENESIS UNDERWAY ALONG THE FRONT RANGE OF
COLORADO. THE UPPER LOW WILL MOVE REACH THE 4-CORNERS SATURDAY
MORNING AND KANSAS BY SATURDAY EVENING. A TROUGH EXTENSION WILL
HANG BACK INTO SOUTHERN ARIZONA AS THE MAIN UPPER LOW CONTINUES
INTO THE MIDWEST. SATURDAY THROUGH SATURDAY NIGHT...THE 300MB JET
WILL BE INCREASING FROM LESS THAN 60 KNOTS IN THE MORNING TO
90-100KTS IN THE EVENING WHICH WILL HELP TO INCREASE 0-6KM BULK
SHEAR INTO THE 60-70 KNOTS RANGE. BEST CAPE VALUES...300-600
J/KG...WILL OCCUR OVER THE SOUTHWEST AND WESTERN COUNTIES SATURDAY
AFTERNOON WHICH SHOULD BE WHERE THE STRONGEST...POSSIBLY SEVERE...
STORMS OCCUR WITH THIS SYSTEM LATE SATURDAY AFTERNOON. ALTHOUGH
SHEAR REMAINS HIGH SATURDAY EVENING AND OVERNIGHT...WEAKENING
INSTABILITY AND MID LEVEL LAPSE RATES SHOULD RESULT IN A
DIMINISHED CHANCE OF SEVERE STORMS BY MID EVENING SATURDAY.
AS THE PACIFIC PUSHES THROUGH THE CWA SATURDAY NIGHT...THE LINE
OF STORMS COULD PRODUCE RAINFALL OF 1/2 TO 1 INCH WITH THE
SOUTHEAST THIRD HAVING THE BEST CHANCE TO SEE 3/4 TO OVER 1 INCH
BEFORE ENDING.
ON SUNDAY...THE REMAINING UPPER TROUGH TO OUR WEST WILL SLIDE ACROSS
THE REGION...AND MAY PRODUCE SOME LIGHT RAIN FROM LINGERING MID
LEVEL MOISTURE...BUT AMOUNTS WILL BE LIGHT. COLDER AIR ARRIVES
BEHIND THE FRONT FOR THE FIRST OF THE WORK WEEK. THE WESTERN AND
NORTHERN AREAS MAY SEE A FREEZE ON TUESDAY MORNING. THE REST OF
NEXT WEEK WILL BE DRY WITH TEMPERATURES MODERATING TO ABOVE NORMAL.
75
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 65 57 68 50 58 / 30 20 30 80 20
WACO, TX 67 58 69 51 58 / 20 20 30 70 60
PARIS, TX 63 53 66 52 58 / 20 20 20 70 40
DENTON, TX 65 58 68 48 57 / 40 20 30 80 20
MCKINNEY, TX 65 56 67 49 58 / 30 20 30 80 30
DALLAS, TX 67 57 68 52 58 / 30 20 30 80 30
TERRELL, TX 65 55 67 53 58 / 20 20 30 70 40
CORSICANA, TX 66 57 69 55 59 / 20 20 20 70 60
TEMPLE, TX 67 59 70 53 59 / 20 20 20 70 70
MINERAL WELLS, TX 66 59 71 47 57 / 40 20 40 60 20
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
05/75
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1040 AM MST FRI MAR 8 2013
.UPDATE...
ISSUED AT 1034 AM MST FRI MAR 8 2013
I AMENDED THE BLIZZARD WARNING TEXT TO INDICATE THAT THE SNOW WILL
LIKELY START DURING THE 6 AM TO 8 AM TIME FRAME...AND THE WINDS
INITIALLY WILL NOT BE ALL THAT STRONG. HOWEVER AS THE MORNING
PROGRESSES WINDS WILL STEADILY INCREASE AND WILL BE GUSTING TO
BLIZZARD CRITERIA BY NOON-ISH. FWIW...RAW GFS WINDS AT 00Z SUNDAY SHOW
NORTH WINDS SUSTAINED AT 42 KNOTS OVER NE EL PASO COUNTY. GIVEN
THIS...POWER OUTAGES WILL BE POSSIBLE DUE TO DOWNED POWER
POLES/WIRES. THE WORST OF THE CONDITIONS SHOULD LAST FOR ABOUT 12-15
HOURS.
I ADDED EASTERN LAS ANIMAS COUNTY INTO THE WINTER STORM WATCH.
THIS WATCH IS IN EFFECT SAT AFTERNOON AND EVENING. LATEST GUIDANCE
INDICATES STRONG WINDS AND PERIODS OF HEAVY SNOW WILL BE POSSIBLE
THIS REGION.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 506 AM MST FRI MAR 8 2013
CLOUDS ARE INCREASING OVR WRN CO THIS MORNING AHEAD OF THE UPPER
LEVEL LOW THAT SATELLITE IMAGES SHOW OFF THE SRN CA COAST. A THICK
BAND OF CLOUDS HAS ALSO MOVED UP OVR THE SERN CORNER OF THE
STATE...BUT THAT SHOULD PUSH EAST LATER THIS MORNING. BY EVENING THE
UPR LOW CENTER IS EXPECTED TO MOVE OVR THE CA AND AZ BORDER AREA.
BOTH THE HRRR AND NAM12 SHOWING PCPN HOLDING OFF OVR THE SWRN MTS
UNTIL AT LEAST LATE MORNING...BUT THEN WE SHOULD SEE PCPN ALL ALONG THE
CONTDVD THIS AFTERNOON...WITH SCT TO LIKELY POPS SPREADING OVR MUCH
OF THE ERN MTS AS WELL AND OVR THE SAN LUIS VALLEY...AND MAINLY
ISOLD CHANCE FOR RAIN OVR THE SERN PLAINS. FOR THIS AFTERNOON THE
NAM IS SHOWING A FEW HUNDRED JOULES OF CAPES OVR THE MTS AND
PORTIONS OF THE I-25 CORRIDOR...WITH LAPSE RATES OF 8-9C/KM OVR THE
FORECAST AREA. WL GO WITH SOME ISOLD THUNDERSTORMS CHANCES THIS
AFTERNOON AND EARLY EVENING. FOR THIS AFTERNOON THE EASTERN SAN JUAN
MTS SHOULD BE THE AREA THAT RECEIVES THE HEAVIEST SNOW...WITH THE
REST OF THE CONTDVD SEEING SNOW...BUT NOT AS MUCH. DURING THE
AFTERNOON SOME STRONG SOUTHERLY WINDS ARE EXPECTED TO DEVELOP OVR
THE FAR SERN CORNER OF THE STATE WITH GUSTS OF 30-40 MPH. MIN RH
VALUES IN THIS AREA ARE EXPECTED TO BE NR 15 PERCENT. HOWEVER FUELS
IN THIS AREA ARE NOT CONSIDERED TO BE CRITICAL. HAVE ISSUED A WINTER
WX ADVISORY FOR ZONE 67 AS WELL AND WL START IT IN THE LATE
AFTERNOON TODAY. TEMPS IN THE EARLY AFTERNOON WL LIKELY BE TOO WARM
TO SEE SNOW OR AT LEAST ANY REAL ACCUMULATIONS UNTIL TEMPS COOL
TOWARD EVENING AND OVERNIGHT.
BY 12Z SAT THE UPR LOW CENTER IS EXPECTED TO MOVE INTO THE SW CORNER
OF CO. AS THIS OCCURS OVERNIGHT A DRY SLOT DEVELOPS OVR THE SERN
PLAINS...AND SHOULD SEE DECREASING CHANCES FOR PCPN OVR THE SAN LUIS
VALLEY AND SERN MTS. AT THE SAME TIME SNOW WL CONTINUE ALONG THE
CONTDVD WITH THE EASTERN SAN JUAN MTS STILL BEING THE MOST FAVORED
LOCATION FOR SIGNIFICANT SNOWFALL.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 506 AM MST FRI MAR 8 2013
...QUICK MOVING STORM TO BRING SNOW AND BLOWING SNOW TO THE AREA
SATURDAY...
SATURDAY-SATURDAY NIGHT...LATEST MODELS REMAIN IN GOOD AGREEMENT OF
A POTENT UPPER LOW ACROSS THE SOUTHERN CALIFORNIA COAST THIS MORNING
LIFTING OUT INTO THE FOUR CORNERS REGION LATE TONIGHT WHICH THEN
CONTINUES TO TRANSLATE ACROSS SOUTHERN COLORADO THROUGH THE DAY
SATURDAY AND INTO NORTHWESTERN KANSAS SATURDAY NIGHT. MOVEMENT OF
THIS SYSTEM KEEPS MODERATE TO HEAVY SNOWFALL ACROSS THE CONTDVD
FRIDAY NIGHT AND SATURDAY WITH DEFORMATION BAND PRECIPITATION
SPREADING EAST ACROSS SOUTH CENTRAL COLORADO AND THE EASTERN MTS
SATURDAY MORNING AND AFTERNOON.
MODELS REMAIN CONSISTENT WITH STRONG NORTHERLY WINDS DEVELOPING
ACROSS THE EASTERN PLAINS LATE SATURDAY MORNING AND PERSISTING
THROUGH THE EARLY EVENING AS AN ASSOCIATED COLD FRONT BLASTS ACROSS
THE PLAINS. PRECIPITATION TYPE STILL IN QUESTION ACROSS THE PLAINS
THOUGH MODEL SOUNDINGS INDICATING PRECIP RAPIDLY CHANGING OVER THE
SNOW AOA 6K FT SATURDAY MORNING AND POSSIBLY LOWERING TO 4K FT UNDER
THE HEAVIER BANDS AS THE SYSTEM LIFTS OUT ACROSS THE EASTERN PLAINS
SATURDAY AFTERNOON AND EVENING.
WITH THAT SAID...HAVE UPGRADED WINTER STORM WATCH TO A BLIZZARD
WARNING FOR NORTHERN EL PASO COUNTY WITH 4-9 INCHES ALONG WITH
STRONG NORTHERLY WINDS UP TO 30 MPH GUSTING TO NEAR 50 MPH AT
TIMES...ESPECIALLY SATURDAY AFTERNOON. HAVE ALSO UPGRADED TELLER
COUNTY AND THE RAMPART RANGE TO WINTER STORM WARNING WITH AMOUNTS
RANGING FROM 6 TO 12 INCHES AND HAVE ISSUED WINTER WEATHER
ADVISORIES FOR LAKE COUNTY...THE WESTERN MOSQUITO RANGE BELOW 9000
FEET AND NORTHWESTERN FREMONT COUNTY ABOVE 8500 FEET. HAVE ALSO
ISSUED A WINTER STORM WATCH FOR THE SANGRE DE CRISTO AND WET MTS
FROM SATURDAY MORNING THROUGH SATURDAY NIGHT. GFS IS STILL A BIT
HEAVY HANDED WITH AMOUNTS ACROSS THE SOUTHEAST MTS AS WELL AS UNDER
THE BANDS AND WILL NEED TO CONTINUE TO MONITOR FOR POSSIBLE
ADDITIONS TO ADVISORIES AND WARNINGS.
SUNDAY-WEDNESDAY...MODEL CONSENSUS CONTINUES TO INDICATE WARMER AND
DRY CONDITIONS ACROSS THE AREA THROUGH THE REST OF EXTENDED PERIOD
WITH MODERATE WESTERLY FLOW ACROSS THE REGION.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 506 AM MST FRI MAR 8 2013
EXPECTED VFR CONDITIONS AT KPUB AND KCOS TODAY AND TONIGHT. LATE
THIS AFTERNOON AND THIS EVENING THERE COULD BE A FEW SHOWERS OR EVEN
A THUNDERSTORM AT OR IN THE VCNTY. KALS SHOULD HAVE VFR CONDITIONS
BUT LATE THIS AFTERNOON SOME SHOWERS OR EVEN A THUNDERSTORM COULD
RESULT IN BRIEF MVFR CONDITIONS. THERE IS ALSO THE POSSIBILITY OF
SOME STRATUS OR BR TOWARD MORNING CAUSING MVFR CONDITIONS...ALTHOUGH
CONFIDENCE IN THIS OCCURRING IT TOO LOW TO INCLUDE IN THE TAF AT THIS
TIME.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 5 AM TO 5 PM MST SATURDAY FOR
COZ059-063-076.
WINTER STORM WATCH FROM SATURDAY MORNING THROUGH SATURDAY
EVENING FOR COZ072>075-079-080.
WINTER STORM WARNING UNTIL 11 PM MST SATURDAY FOR COZ058-060.
WINTER STORM WATCH FROM SATURDAY AFTERNOON THROUGH SATURDAY
EVENING FOR COZ094.
WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO 5 PM MST
SATURDAY FOR COZ067.
WINTER STORM WARNING UNTIL 8 PM MST SATURDAY FOR COZ066-068.
WINTER STORM WARNING FROM 5 AM TO 8 PM MST SATURDAY FOR COZ081-
082.
BLIZZARD WARNING FROM 5 AM TO 8 PM MST SATURDAY FOR COZ084.
&&
$$
UPDATE...HODANISH
SHORT TERM...28
LONG TERM...MW
AVIATION...28
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1036 AM MST FRI MAR 8 2013
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 506 AM MST FRI MAR 8 2013
CLOUDS ARE INCREASING OVR WRN CO THIS MORNING AHEAD OF THE UPPER
LEVEL LOW THAT SATELLITE IMAGES SHOW OFF THE SRN CA COAST. A THICK
BAND OF CLOUDS HAS ALSO MOVED UP OVR THE SERN CORNER OF THE
STATE...BUT THAT SHOULD PUSH EAST LATER THIS MORNING. BY EVENING THE
UPR LOW CENTER IS EXPECTED TO MOVE OVR THE CA AND AZ BORDER AREA.
BOTH THE HRRR AND NAM12 SHOWING PCPN HOLDING OFF OVR THE SWRN MTS
UNTIL AT LEAST LATE MORNING...BUT THEN WE SHOULD SEE PCPN ALL ALONG THE
CONTDVD THIS AFTERNOON...WITH SCT TO LIKELY POPS SPREADING OVR MUCH
OF THE ERN MTS AS WELL AND OVR THE SAN LUIS VALLEY...AND MAINLY
ISOLD CHANCE FOR RAIN OVR THE SERN PLAINS. FOR THIS AFTERNOON THE
NAM IS SHOWING A FEW HUNDRED JOULES OF CAPES OVR THE MTS AND
PORTIONS OF THE I-25 CORRIDOR...WITH LAPSE RATES OF 8-9C/KM OVR THE
FORECAST AREA. WL GO WITH SOME ISOLD THUNDERSTORMS CHANCES THIS
AFTERNOON AND EARLY EVENING. FOR THIS AFTERNOON THE EASTERN SAN JUAN
MTS SHOULD BE THE AREA THAT RECEIVES THE HEAVIEST SNOW...WITH THE
REST OF THE CONTDVD SEEING SNOW...BUT NOT AS MUCH. DURING THE
AFTERNOON SOME STRONG SOUTHERLY WINDS ARE EXPECTED TO DEVELOP OVR
THE FAR SERN CORNER OF THE STATE WITH GUSTS OF 30-40 MPH. MIN RH
VALUES IN THIS AREA ARE EXPECTED TO BE NR 15 PERCENT. HOWEVER FUELS
IN THIS AREA ARE NOT CONSIDERED TO BE CRITICAL. HAVE ISSUED A WINTER
WX ADVISORY FOR ZONE 67 AS WELL AND WL START IT IN THE LATE
AFTERNOON TODAY. TEMPS IN THE EARLY AFTERNOON WL LIKELY BE TOO WARM
TO SEE SNOW OR AT LEAST ANY REAL ACCUMULATIONS UNTIL TEMPS COOL
TOWARD EVENING AND OVERNIGHT.
BY 12Z SAT THE UPR LOW CENTER IS EXPECTED TO MOVE INTO THE SW CORNER
OF CO. AS THIS OCCURS OVERNIGHT A DRY SLOT DEVELOPS OVR THE SERN
PLAINS...AND SHOULD SEE DECREASING CHANCES FOR PCPN OVR THE SAN LUIS
VALLEY AND SERN MTS. AT THE SAME TIME SNOW WL CONTINUE ALONG THE
CONTDVD WITH THE EASTERN SAN JUAN MTS STILL BEING THE MOST FAVORED
LOCATION FOR SIGNIFICANT SNOWFALL.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 506 AM MST FRI MAR 8 2013
...QUICK MOVING STORM TO BRING SNOW AND BLOWING SNOW TO THE AREA
SATURDAY...
SATURDAY-SATURDAY NIGHT...LATEST MODELS REMAIN IN GOOD AGREEMENT OF
A POTENT UPPER LOW ACROSS THE SOUTHERN CALIFORNIA COAST THIS MORNING
LIFTING OUT INTO THE FOUR CORNERS REGION LATE TONIGHT WHICH THEN
CONTINUES TO TRANSLATE ACROSS SOUTHERN COLORADO THROUGH THE DAY
SATURDAY AND INTO NORTHWESTERN KANSAS SATURDAY NIGHT. MOVEMENT OF
THIS SYSTEM KEEPS MODERATE TO HEAVY SNOWFALL ACROSS THE CONTDVD
FRIDAY NIGHT AND SATURDAY WITH DEFORMATION BAND PRECIPITATION
SPREADING EAST ACROSS SOUTH CENTRAL COLORADO AND THE EASTERN MTS
SATURDAY MORNING AND AFTERNOON.
MODELS REMAIN CONSISTENT WITH STRONG NORTHERLY WINDS DEVELOPING
ACROSS THE EASTERN PLAINS LATE SATURDAY MORNING AND PERSISTING
THROUGH THE EARLY EVENING AS AN ASSOCIATED COLD FRONT BLASTS ACROSS
THE PLAINS. PRECIPITATION TYPE STILL IN QUESTION ACROSS THE PLAINS
THOUGH MODEL SOUNDINGS INDICATING PRECIP RAPIDLY CHANGING OVER THE
SNOW AOA 6K FT SATURDAY MORNING AND POSSIBLY LOWERING TO 4K FT UNDER
THE HEAVIER BANDS AS THE SYSTEM LIFTS OUT ACROSS THE EASTERN PLAINS
SATURDAY AFTERNOON AND EVENING.
WITH THAT SAID...HAVE UPGRADED WINTER STORM WATCH TO A BLIZZARD
WARNING FOR NORTHERN EL PASO COUNTY WITH 4-9 INCHES ALONG WITH
STRONG NORTHERLY WINDS UP TO 30 MPH GUSTING TO NEAR 50 MPH AT
TIMES...ESPECIALLY SATURDAY AFTERNOON. HAVE ALSO UPGRADED TELLER
COUNTY AND THE RAMPART RANGE TO WINTER STORM WARNING WITH AMOUNTS
RANGING FROM 6 TO 12 INCHES AND HAVE ISSUED WINTER WEATHER
ADVISORIES FOR LAKE COUNTY...THE WESTERN MOSQUITO RANGE BELOW 9000
FEET AND NORTHWESTERN FREMONT COUNTY ABOVE 8500 FEET. HAVE ALSO
ISSUED A WINTER STORM WATCH FOR THE SANGRE DE CRISTO AND WET MTS
FROM SATURDAY MORNING THROUGH SATURDAY NIGHT. GFS IS STILL A BIT
HEAVY HANDED WITH AMOUNTS ACROSS THE SOUTHEAST MTS AS WELL AS UNDER
THE BANDS AND WILL NEED TO CONTINUE TO MONITOR FOR POSSIBLE
ADDITIONS TO ADVISORIES AND WARNINGS.
SUNDAY-WEDNESDAY...MODEL CONSENSUS CONTINUES TO INDICATE WARMER AND
DRY CONDITIONS ACROSS THE AREA THROUGH THE REST OF EXTENDED PERIOD
WITH MODERATE WESTERLY FLOW ACROSS THE REGION.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1017 AM MST FRI MAR 8 2013
VFR CONDITIONS EXPECTED TODAY WITH SHOWERS MOVING OFF THE
MOUNTAINS...POSSIBLY AFFECTING KALS AND KCOS IN THE AFTERNOON.
WILL CONTINUE TO CARRY VCSH IN BOTH TAF SITES AFTER 21Z FOR KALS
STARTING AROUND 00Z FOR KCOS. CIGS SHOULD STAY VFR WITH MAIN
THREAT BEING GUSTY ERRATIC WINDS.
MAIN BRUNT OF THE STORM WILL AFFECT KCOS AND KPUB AFTER 15Z-16Z ON
SATURDAY WITH A BRISK WIND SHIFT OUT OF THE NORTH GUSTING TO 35-40
KTS BY 18Z OR SHORTLY AFTER. SNOW AND BLOWING SNOW WILL SPREAD IN
QUICKLY BEHIND THE FRONT WITH DETERIORATING CONDITIONS WITH IFR CIGS
AND EVEN PERIODS OF LIFR VIS WITH BLSN. WINDOW FOR BEST ACCUMULATING
SNOW POTENTIAL WILL CONTINUE THROUGH 22Z SAT FOR KCOS AND THROUGH
23Z FOR KPUB...WITH ACCUMULATIONS OF 1-3 INCHES POSSIBLE FOR
KCOS...AND GENERALLY UP TO AN INCH MAINLY ON GRASSY SURFACES FOR
KPUB. STRONG NORTH WINDS WILL CONTINUE THROUGH THE EVENING...WITH
BLSN POSSIBLE AT THE KCOS TERMINAL THROUGH 03Z. KALS MAY SEE A
QUICK SHOT FOR -SHSN AND VFR TO MVFR CIGS/VIS SAT AFTERNOON...JUST
OUTSIDE THE TAF FORECAST PERIOD.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 5 AM TO 5 PM MST SATURDAY FOR
COZ059-063-076.
WINTER STORM WATCH FROM SATURDAY MORNING THROUGH SATURDAY
EVENING FOR COZ072>075-079-080.
WINTER STORM WARNING UNTIL 11 PM MST SATURDAY FOR COZ058-060.
WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO 5 PM MST
SATURDAY FOR COZ067.
WINTER STORM WARNING UNTIL 8 PM MST SATURDAY FOR COZ066-068.
WINTER STORM WARNING FROM 5 AM TO 8 PM MST SATURDAY FOR COZ081-
082.
BLIZZARD WARNING FROM 5 AM TO 8 PM MST SATURDAY FOR COZ084.
&&
$$
SHORT TERM...28
LONG TERM...MW
AVIATION...KT
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1202 PM CST FRI MAR 8 2013
...UPDATE TO AVIATION...
.DISCUSSION...
SHORT RANGE FORECAST (TODAY THROUGH SATURDAY)...
09Z RAP ANALYSIS AND SURFACE OBS SHOW A TIGHTENING SURFACE PRESSURE
GRADIENT TAKING FORM ACROSS THE AREA AS AN AREA OF LOW PRESSURE SITS
OVER SE COLORADO. WATER VAPOR IMAGERY INDICATES THAT A MID TO UPPER
LEVEL TROUGH CURRENTLY SITS OVER SOUTHERN CALIFORNIA...WITH A STRONG
SOUTH/SOUTHWEST COMPONENT TO THE MID/UPPER WINDS WELL TO THE EAST OF
THE TROUGH CENTER. WITHIN THIS MID LEVEL SOUTHERLY FLOW WATER VAPOR
IMAGERY SHOWS SOME MOISTURE WORKING ITS WAY THROUGH THE SOUTHERN
HIGH PLAINS INTO WESTERN KANSAS. THIS TROUGH WILL BE THE IMPETUS
BEHIND RAIN CHANCES LATER TONIGHT THROUGH THE WEEKEND. AS THE
SURFACE TROUGH TAKES FORM THE SURFACE PRESSURE GRADIENT WILL BECOME
A BIT STRONGER ALLOWING FOR THE WINDS TO PICK UP THROUGHOUT THE DAY.
EXPECT S/SE WINDS TO EVENTUALLY INCREASE TO BETWEEN 15 AND 25
MPH...WITH GUSTS UP TO 30. LOW LEVEL SOUTHERLY WINDS WILL ALSO
TRANSPORT WARM/MOIST AIR INTO THE AREA. EXPECT DEWPOINTS TO INCREASE
THROUGHOUT THE DAY TO THE MID 40S BY LATE TONIGHT. ISENTROPIC CHARTS
SHOW A STRONG ISENTROPIC COMPONENT WITHIN THE S/SE LOW AND MID LEVEL
WINDS WHICH MAY LEAD TO INCREASING CLOUDS THROUGH THE AFTERNOON
HOURS...HOWEVER CONDENSATION PRESSURE DEFICITS LOOK TO REMAIN TOO
HIGH TO PRODUCE ANY PRECIPITATION UNTIL LATER THIS EVENING. WITH THE
MAIN AREA OF MID LEVEL ENERGY HANGING OFF TO THE WEST THE MAIN
INFLUENCE FOR FRIDAY NIGHT PRECIP WILL BE THE STRONG ISENTROPIC
COMPONENT. FORECAST SOUNDING CORROBORATE WHAT THE ISENTROPIC
SURFACES SUGGEST...WHICH IS THAT THE COLUMN WILL HAVE SOME DRY AIR
TO OVERCOME THROUGHOUT THE DAY ON FRIDAY. EVENTUALLY IT WILL
OVERCOME THE DRY AIR AND PRECIP WILL BEGIN FRIDAY EVENING. PRECIP
COVERAGE AND INTENSITY WILL INCREASE THROUGH THE NIGHT AS THE COLUMN
BECOMES COMPLETELY SATURATED.
BY LATE FRIDAY NIGHT INTO EARLY SATURDAY MORNING THE MID LEVEL
TROUGH WILL BEGIN MOVING THROUGH THE AREA. THE EXTRA LARGE SCALE
ASCENT SHOULD ALLOW FOR MORE EFFICIENT RAIN PROCESSES...CAUSING
PERIODS OF MODERATE RAIN TO OCCUR THROUGH MID DAY ON SATURDAY. ALONG
WITH THE BETTER LARGE SCALE ASCENT THE COOLER TEMPS ALOFT ASSOCIATED
WITH THE LARGE TROUGH WILL ALLOW FOR SOME ELEVATED STEEP LAPSE
RATES...MAKING ELEVATED CAPE LEVELS APPROACH 500 J/KG. AS A RESULT
PERIODS OF THUNDERSTORMS WILL BE LIKELY LATE FRIDAY NIGHT THROUGH
THE DAY ON SATURDAY. ALTHOUGH THE THUNDERSTORMS ARE NOT EXPECTED TO
BE VIGOROUS THE MODEST CAPE ALONG WITH 40 TO 50 KTS OF 0-6 SHEAR IT
IS POSSIBLE THAT AN ISOLATED CELL OR TWO COULD BECOME STRONG WITH
PERHAPS A SEVERE HAIL REPORT OR TWO SATURDAY MORNING/AFTERNOON.
AS THE SYSTEM PROGRESSES TO THE EAST MODELS SEEM TO AGREE ON THE
PLACEMENT AND TIMING OF A DRY SLOT OF MID LEVEL AIR CUTTING OFF THE
EFFICIENT PRECIP PROCESSES BY SATURDAY AFTERNOON/EVENING. THIS WILL
LIKELY SPELL AN END TO THE MODERATE PRECIP...ALTHOUGH SOME LIGHT
PRECIP MAY LINGER THROUGH LATE SATURDAY NIGHT. ACROSS THE NORTHERN
COUNTIES THERE WILL REMAIN A CHANCE FOR SOME VERY LIGHT SNOW FALL
SATURDAY NIGHT AS A WEAK TROWAL FORMS ACROSS CENTRAL NEBRASKA. GIVEN
THAT THE REGION WILL EXPERIENCE SEVERAL DAYS IN A ROW OF ABOVE
FREEZING TEMPERATURES AS WELL AS A WET GROUND FROM THE SATURDAY
RAINFALL EXPECT SNOW ACCUMULATIONS TO BE TOUGH TO COME BY. PERHAPS A
DUSTING OF SNOW WILL BE POSSIBLE ON GRASSY AND ELEVATED
SURFACES...BUT EXPECT PAVED SURFACES TO STAY WET AS OPPOSED TO SNOW
PACKED. BY SUNDAY AFTERNOON THE SYSTEM SHOULD MOVE OFF TO THE EAST
ENDING ALL PRECIPITATIONS CHANCES.
QPF FORECAST FOR THIS SYSTEM REMAINS A BIT CONSERVATIVE AS MODELS
HAVE OVERDONE PRECIP AMOUNT IN RECENT SYSTEMS. ON THE LOWER END THIS
SYSTEM SHOULD HAVE NO PROBLEM PRODUCING A QUARTER INCH OF
PRECIPITATION AREA-WIDE...WITH PERHAPS A FEW ISOLATED AREAS GETTING
A FULL INCH. MOST AREAS WILL LIKELY GET SOMEWHERE BETWEEN THOSE TWO
VALUES IN LIQUID PRECIP BETWEEN FRIDAY NIGHT AND SUNDAY MORNING.
MID RANGE AND EXTENDED FORECAST (MONDAY THROUGH THURSDAY)...
A STRONG PUSH OF COLD AIR WILL FOLLOW THE SYSTEM THROUGH THE AREA
AND TO THE EAST. THIS PUSH OF COLD AIR WILL LIKELY BRING A COOL DOWN
FOR SUNDAY AND MONDAY BEFORE SOUTHERLY FLOW RECOMMENCES...BRINGING
WARM/MOIST AIR BACK INTO THE AREA. FOR A FEW DAYS NOW MODELS HAVE
SHOWN THAT THE AREA WILL STAY DRY THROUGH NEXT WORK WEEK WITH A
GRADUAL...BUT NOTICEABLE WARM UP. WITH A MID LEVEL RIDGE OFF TO THE
WEST...GRADUALLY CREEPING EASTWARD THROUGH THE WEEK AND MOSTLY
PERSISTENT SOUTHERLY FLOW EXPECT TUESDAY THROUGH THURSDAY TO BRING
ABOVE SEASONALLY NORMAL TEMPERATURES.
JL
&&
.AVIATION...
VFR CONDITIONS EXPECTED THROUGH 00Z SATURDAY. VCTS EXPECTED AFTER
00Z WITH VFR CIGS THEN EXPECT MORE COVERAGE WITH SHOWERS AND
ISOLATED THUNDERSTORMS AFTER 06Z THROUGH THE END OF THE PERIOD.
FORECAST SOUNDINGS SUGGEST MVFR CIGS TO PREVAIL AFTER 12Z
SATURDAY. WINDS CONTINUE OUT OF THE SOUTHEAST THROUGH THE PERIOD
AROUND 12 TO 14 KTS. SOME GUSTS TO 20 KTS POSSIBLE THROUGH 00Z.
53
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
437 PM EST FRI MAR 8 2013
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 431 PM EST FRI MAR 8 2013
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW SPLIT FLOW DOMINATING
NAMERICA. IN THE SRN STREAM...POTENT LOOKING SHORTWAVE HAS MOVED
ONSHORE OVER SRN CA WHILE ANOTHER WAVE IS DROPPING S OVER WRN OR/NRN
CA. BOTH OF THESE WAVES WILL PLAY A ROLE IN THE WX ACROSS THE GREAT
LAKES IN THE COMING DAYS. DOWNSTREAM OF THE WRN TROF...RIDGING IS
OVER THE CNTRL CONUS. TO THE N...ONE SHORTWAVE IS TRACKING THRU NRN
ONTARIO. ANOTHER WAVE IS DROPPING SE INTO ALBERTA ON THE PERIPHERY
OF POLAR VORTEX CENTERED JUST N OF HUDSON BAY. THIS WAVE WILL ALSO
PLAY A ROLE IN THE WX OVER THE GREAT LAKES IN THE COMING DAYS.
CLOSER TO HOME...LOW CLOUDS HAVE LINGERED OVER THE ERN FCST AREA IN
SRLY FLOW OFF LAKE MI. HOWEVER...RECENTLY...ONLY A SMALL AREA OF
STRATOCU REMAINS...STREAMING ONSHORE IN SRN SCHOOLCRAFT COUNTY.
ELSEWHERE...EARLY MARCH SUNSHINE IS DOING ITS JOB ON THE LOWER
ALBEDO FORESTED LAND OF THE U.P. TEMPS HAVE PUSHED INTO THE 40S AT A
NUMBER OF OBS SITES OVER WRN UPPER MI.
IN THE SHORT TERM...QUIET WX TONIGHT WILL GIVE WAY TO INCREASING
PCPN CHANCES SAT UNDER STRENGTHENING WAA REGIME AHEAD OF NRN STREAM
WAVE THAT WILL BE MOVING INTO SRN MANITOBA/ND AND SRN STREAM WAVE
EMERGING OVER THE SRN HIGH PLAINS. TONIGHT...SRLY FLOW WILL BE ON
THE INCREASE AHEAD OF THE AFOREMENTIONED SHORTWAVES. THERE IS THE
USUAL CONCERN UNDER SRLY FLOW THAT LOW CLOUDS MAY DEVELOP. IN THIS
CASE...HOWEVER...THE NAM AND GFS SHOW DRY AIR ADVECTION TONIGHT AT
THE LOW-LEVELS AS TRAJECTORIES STILL HAVE SUFFICIENT COMPONENT
EMANATING FROM RETREATING HIGH PRES. SO...LOW CLOUDS MAY NOT REALLY
BE AN ISSUE TONIGHT. IF ANY VERY LOW/SHALLOW STRATUS DOES DEVELOP...
IT SHOULD ONLY BE IN THE AREAS WITH BEST UPSLOPING OVER CNTRL UPPER
MI. OTHERWISE...EXPECT GENERALLY PARTLY CLOUDY SKIES IN THE
EVENING...AND THEN AN INCREASE IN HIGH CLOUDS OVERNIGHT. TYPICAL FOR
THIS TYPE OF INITIALLY RATHER WEAK SRLY FLOW...EXPECT LOWEST MINS
NEAR THE BAY OF GREEN BAY AS ICE COVER ENHANCES COOLING AND
STRENGTHENS NOCTURNAL INVERSION IN THAT AREA. LOWS SHOULD BE AROUND
20F THERE.
ON SAT...UNDER STRONG WAA AND ISENTROPIC ASCENT (295K SFC)...EXPECT
PCPN TO DEVELOP FROM W TO E AS LOW-LEVEL DRY AIR IS EVENTUALLY
OVERCOME. TRAJECTORIES SUGGEST THERE WILL BE SOME MAINTENANCE
OF THE LOW-LEVEL DRY AIR OVER THE E EVEN AS FORCING AND RESULTING
PCPN ALOFT OVERSPREAD THAT AREA. SO...POPS WILL SHOW A GRADIENT FROM
CATEGORICAL W TO JUST CHC E LATE. IT`S QUITE POSSIBLE THE E MAY
NOT SEE ANY PCPN SAT. AS FOR PTYPE...IT`S A CHALLENGE AS IT ALMOST
ALWAYS IS WHEN IT`S NOT COLD ENOUGH FOR JUST SNOW OR WARM ENOUGH FOR
JUST RAIN. THERE WILL BE THE USUAL BATTLE BETWEEN STRONG WAA AND THE
COOLING IT GENERATES THRU ASCENT AS WELL AS EVAPORATIVE COOLING
EARLY ON. BELIEVE THE EVAPORATIVE COOLING EARLY ON WILL LEAD TO
PREDOMINANTLY SNOW AS THE PTYPE INITIALLY. THEREAFTER...FCST
SOUNDINGS SHOW PROFILE GENERALLY HOVERING AROUND 0C IN THE LOWER
LEVELS...FLUCTUATING BASED ON ASCENT/PCPN INTENSITY. MEANWHILE...THE
NEAR SFC LAYER MAY RESPOND A LITTLE TO DAYTIME HEATING...PUSHING THE
ODDS TOWARD RAIN. AT THIS POINT...WILL INCLUDE SNOW AS THE GENERAL
PREVAILING PTYPE IN MOST AREAS WITH A MENTION OF RAIN. INCLUDED FZRA
AS WELL WHERE TEMPS ARE AROUND FREEZING. IF THERE IS FZRA...IT
SHOULD BE CONFINED TO THE MORNING/EARLY AFTN BEFORE SURFACES RESPOND
TO WEAK DAYTIME HEATING. WITH TEMPS PUSHING INTO THE MID 30S...
WET/SLUSHY SNOW ACCUMULATIONS WILL BE MINOR...MAYBE AROUND AN INCH.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 431 PM EST FRI MAR 8 2013
SATURDAY NIGHT...
THE MODELS HAVE COME INTO BETTER AGREEMENT WITH THE EVOLUTION OF THE
SYOPTIC PATTERN WITH A PROGRESSIVE PATTERN AND LITTLE PHASING
BETWEEN THE NRN STREAM MID LEVEL TROUGH MOVING THROUGH NRN ONTARIO
AND THE NRN GREATLAKES AND THE SRN STREAM SHORTWAVE MOVING EAST FROM
THE PLAINS.
ABUNDANT MOISTURE INFLOW WITH MODERATE TO STRONG 285K-300K
ISENTROPIC LIFT AND A PERIOD OF 700-600 MB FGEN SHOULD SUPPORT A
BAND OF PCPN THROUGH THE CWA...ESPECIALLY BTWN 00Z-06Z WITH QPF
AMOUNTS TO AROUND 0.25 INCH. CONFIDENCE IS ALSO HIGHER THAT A
SIGNIFCANT (1C TO 3C) WARM LAYER WILL SPREAD THROUGH MOST OF THE CWA
GIVEN STRONG WAA WITH SW 40-45 KT 850 MB WINDS BY 00Z/SUN. GENERALLY
UTILIZED NAM/GEM LOW LEVEL THERMAL PROFILE TO DELINEATE PCPN TYPE
PATTERN. WITH ENOUGH WARMTH LINGERING FROM DAYTIME HEATING...ANY SFC
COLD LAYER WILL BE LESS PRONOUNCED LIMITING POTENTIAL FOR FZRA.
SO...MAINLY RA/SN MIX EXPECTED WITH THE GREATEST SNOW CHANCES OVER
THE WEST HALF. WITH LOW SLR AOB 10/1...ANY WET SNOWFALL AMOUNTS
SHOULD ONLY AMOUNT TO AN INCH OR TWO AT MOST.
SUNDAY...THERE WERE GREATER MODEL DIFFERENCES AS THE GFS ALLOWS
ANOTHER DEFORMATION BAND OF PCPN TO LIFT INTO UPPER ASSOCIATED WITH
THE SRN STREAM SHRTWV. SINCE THE GLOBAL GEM/ECMWF CONTINUE TO SHOW A
MORE PROGRESSIVE SOLUTION...THE FCST CONTINUES WITH THE IDEA OF
TAPERING OFF POPS/QPF FROM WEST TO EAST WITH MAINLY JUST CHANCE POPS
BY AFTERNOON. SOME LAKE ENHANCED SNOW MAY DEVELOP BUT WITH THE
SYNOPTIC SCALE UPWARD MOTION AND DEEPER MOISTURE DEPARTING...ANY
AMOUNTS SHOULD BE LIGHT.
SUN NIGHT INTO MON...850 MB TEMPS DROPPING INTO THE -12C TO -14C
ALONG WITH CONTINUED CYCLONIC NRLY FLOW COULD STILL SUPPORT SOME
LES. HOWEVER...WITH STRONG 850-700 MB DRYING...ANY AMOUNTS
ARE EXPECTED TO BE LIGHT
TUE-FRI...MDLS WERE CONSISTENT WITH A WEAK CLIPPER SHORTWAVE AND SFC
TROUGH MOVING THROUGH THE UPPER GREAT LAKES MON NIGHT INTO TUE. THE FAVORED
ECMWF REMAINED MORE AMPLIFIED WITH THE ERN GREAT LAKES TROUGH BY WED
WITH COLDER AIR AVAILABLE FOR SOME NW FLOW LES COMPARED TO THE THE
GFS. CONFIDENCE IN DETAILS DROPS OFF BY THU-FRI WITH REGARD TO THE
POSITION/STRENGTH OF THE NEXT SHORTWAVE THAT COULD BRING SNOW CHANCES
INTO THE REGION. TEMPS SHOULD REMAIN AT OR BELOW SEASONAL AVERAGES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1238 PM EST FRI MAR 8 2013
VFR CONDITIONS SHOULD PREVAIL THRU TONIGHT AT KIWD/KCMX/KSAW GIVEN
DRYNESS OF AIR MASS EXPECTED TO BE OVER THE AREA. ONLY EXCEPTION
MIGHT BE KSAW AS UPSLOPE FLOW TONIGHT COULD LEAD TO SOME LOW STRATUS
DEVELOPING. RIGHT NOW...THAT APPEARS UNLIKELY...BUT IT WILL BE
SOMETHING TO MONITOR. APPROACHING LOW PRES TROF SHOULD BRING SOME
PCPN/MVFR CONDITIONS TO KIWD/KCMX MID TO LATE MORNING SAT. TEMP
PROFILES SUGGEST POTENTIAL FOR A WINTRY MIX...BUT EVAPORATIVE
COOLING AS PCPN BEGINS SHOULD LEAD TO PTYPE BEING SNOW.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 431 PM EST FRI MAR 8 2013
SOUTHERLY FLOW WILL DOMINATE TONIGHT THRU SAT EVENING AHEAD OF AN
APPROACHING LOW PRES TROF. TYPICAL FOR SOUTHERLY FLOW...STRONGEST
WINDS WILL BE OVER ERN LAKE SUPERIOR...REACHING UPWARDS OF 30KT SAT
AFTN/EVENING. TROF WILL THEN PASS ACROSS LAKE SUPERIOR LATE SAT
NIGHT/SUN...BRINGING A SHIFT TO 20-30KT NW WINDS. WINDS WILL THEN
SLOWLY SUBSIDE LATE SUN NIGHT/MON...FALLING TO UNDER 15KT FOR MON
NIGHT/TUE. MAY SEE A SLIGHT INCREASE IN WINDS WED.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...JLB
AVIATION...ROLFSON
MARINE...JLB
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1155 AM CST FRI MAR 8 2013
.DISCUSSION...LATEST RADAR IMAGERY...BOWMAN AND BISMARCK RADARS
CONTINUE TO REFLECTIVITY`S ENHANCING IN THE SOUTHWEST. WILL CONTINUE
WITH THE LIKELY POPS THIS AFTERNOON...MOVING UP ALONG THE WESTERN
BORDER TOWARD 00Z SATURDAY...PER LATEST RAP AND GFS. COULD BE A
MIX OF SLEET AND SNOW AS WELL WITH SOUNDINGS ADVERTISING A MODEST
WARM POCKET WITH TEMPS AROUND +1 TO +2C IN A SHALLOW LAYER.
CONCERN FOR TONIGHT AND SATURDAY IS POSSIBLE WINTER WEATHER
ADVISORY IN THE FAR SOUTHEAST COUNTIES. 12Z MODELS REMAIN ERRATIC
ON MAX/MIN QPF POSSIBILITIES. CONSIDERING GOING THE MIDDLE OF THE
ROAD WHICH MEANS A 2 TO 4 INCH POSSIBILITY IN THE FAR SOUTHEAST.
WILL CONTINUE TO LOOK AT THINGS AND HAVE A DECISION MADE LATER
THIS AFTERNOON. REST OF FORECAST REMAINS ON TRACK.
&&
.AVIATION...AT NOON CST...COLD FRONT EXTENDED FROM A LOW AT
MANITOBA/ONTARIO BORDER TO NEAR PEMBINA TO NEAR KJMS. NORTHWEST
WINDS AT KMOT/KJMS EARLY THIS AFTERNOON. MEANWHILE THE SOUTHERN
STORM SYSTEM WITH A LOW OVER COLORADO/WYOMING WILL KEEP ELY/NELY
WINDS AT KISN/KDIK/KBIS...AND BRING ELY/NELY WINDS TO KMOT/KJMS BY
21Z-00Z THIS AFTERNOON. LARGE MID-LEVEL CLOUD SHIELD MOVING
NORTHWARD FROM THE SOUTH WILL ENCOMPASS TAF SITES. AT THE SAME
TIME...EXPECT MVFR CIGS TO DEVELOP AT ALL TAF SITES BEGINNING AT
KDIK WITH EASTERLY UPSLOPE FLOW AND SPREADING NORTH AND EAST AFT
00Z. LIGHT SNOW WITH POSSIBILITY MIX WITH SLEET AT KDIK THIS
AFTERNOON...THEN CHANCES OF LIGHT SNOW TONIGHT AT MOST TAF SITES.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
DISCUSSION...KS
AVIATION...JV
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
1241 PM EST FRI MAR 8 2013
.SYNOPSIS...
LOW PRESSURE OFF THE EAST COAST DRIFTS SLOWLY AWAY TODAY...ALLOWING
HIGH PRESSURE TO BUILD IN THIS WEEKEND. A COLD FRONT AND WAVE OF LOW
PRESSURE MOVE THROUGH MONDAY INTO TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
INCREASED THE CLOUD COVER PER LOCAL MODEL AND RUC 900-850MB
MOISTURE ADVECTION FROM THE NORTH. NAM NOT PICKING UP ON THIS AS
WELL.
PREVIOUS DISCUSSION FOLLOWS...
OVERALL RELATIVELY QUIET WEATHER IN THE NEAR TERM PERIOD. DOUBLE
BARREL LOW PRESSURE CONTINUES TO REMAIN ALONG THE EAST COAST OF THE
U.S...PLACING THE CWA IN A NW FLOW PATTERN...WITH LIGHT SNOW
SHOWER/FLURRY ACTIVITY CONTINUING ACROSS NORTHERN ZONES. MUCH OF
THIS ACTIVITY WILL TAPER OFF BY LATE MORNING OR EARLY AFTERNOON...AS
RIDGE OF HIGH PRESSURE FROM THE WEST BUILDS IN...PUSHING THE LOW
FARTHER TO THE EAST. THIS COMBINED WITH SURFACE HIGH PRESSURE
BUILDING IN FROM THE NORTH...WILL GRADUALLY RESULT IN LESS FAVORABLE
FLOW FOR CONTINUED SNOW SHOWER ACTIVITY. DRIED OUT POPS ACROSS THE
CWA SEVERAL HOURS EARLIER THAN THE PREVIOUS FORECAST.
LOW LEVEL MOISTURE TRAPPED BENEATH INVERSION IS GRADUALLY STARTING
TO ERODE...AND EXPECT IT TO CONTINUE THROUGHOUT THE DAY...WITH
NORTHERN/MOUNTAIN ZONES SLOWER TO CLEAR. WITH THE CLEARING SKY...AND
BUILDING HIGH...EXPECT A NIGHT OF GOOD RADIATIONAL COOLING...AND
ELECTED TO GO ON THE COLDER SIDE OF GUIDANCE...BUT KEPT RIDGE TOPS
WARMER THAN MOUNTAIN VALLEYS DUE TO BUILDING RIDGE. MAY EVEN SEE
SOME PATCHY FOG IN MOUNTAIN VALLEYS SATURDAY MORNING...BUT NOTHING
WIDESPREAD. ELECTED TO BUMP MAX TEMPS FOR TODAY DOWN SLIGHTLY FROM
PREVIOUS FORECAST AS AREA REMAINS IN NORTHERLY FLOW.
&&
.SHORT TERM /SATURDAY THROUGH MONDAY/...
NEED A SPRING FEVER ALERT IN THE HWO FOR THE WEEKEND.
NAM12 APPEARS FAST WITH PASSAGE OF FRONT SUN NT. WENT WITH OTHER
GLOBAL MODELS...WHICH HOLD THE FRONT...AND ITS ASSOCIATED
PRECIPITATION...UP FOR A TIME SUN NT...ON ACCOUNT OF A SOUTHERN
STREAM WAVE. THE FRONT THEN STARTS MOVING E AGAIN LATER SUN NT AND
MON...AS THE WAVE GOES BY...THERE ARE GLOBAL MODEL INCONSISTENCIES
IN THE TIMING OF THIS WAVE. GFS INSTABILITY PARAMETERS DO NOT
REALLY SUPPORT THUNDER S OF THE WAVE AND AHEAD OF THE COLD FRONT MON
AFTERNOON. HOWEVER...LEFT THE SLIGHT CHANCE ALREADY IN THE GRIDS
ALONE FOR NOW PENDING POSSIBLE CHANGES IN FCST PARAMETERS.
NO MAJOR CHANGES IN TEMPERATURES WHICH JIBED WELL IN LIGHT OF LATEST
GUIDANCE. LOWERED DEW POINTS AND LOWS A LITTLE OVER THE WEEKEND
WHILE HIGHS ARE AT OR ABOVE PREVIOUS SAT AND UNCHANGED SUN...MID 60S
IN CHARLESTON. COOLING FROM THE W MON WILL BE A FUNCTION OF TIMING
OF THE FRONT AND ITS ASSOCIATED PRECIPITATION...SOME OF WHICH MAY BE
BEHIND THE FRONT DEPENDING UPON THE TIMING OF THE WAVE. HIGH
TERRAIN WILL BE COOLER W/R FCST H85 TEMPERATURES THAN USUAL UNTIL
THE FOOT-PLUS SNOW PACK UP THERE IS ABOUT GONE.
&&
.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
MOISTURE FROM THE LEADING EDGE OF THE NEXT FRONTAL SYSTEM WILL BEGIN
TO SPREAD OVER THE WESTERN PORTIONS OF THE FORECAST AREA LATE SUNDAY
NIGHT AS THE WEEKENDS UPPER LEVEL RIDGE SLIDES EAST INTO THE
ATLANTIC. RAINFALL WILL BECOME MORE WIDESPREAD THROUGH THE DAY
MONDAY AS A FRONTAL SYSTEM WITH A GOOD SOUTHERLY FETCH SHIFTS EAST.
WITH TEMPERATURES REMAINING WARM DURING THIS TIME PERIOD WILL NEED
TO WATCH THE FRONT CLOSELY FOR HYDRO CONCERNS. SO FAR MODELS ARE
SHIFTING IT EAST QUICKLY ENOUGH TO KEEP PRECIPITATION AMOUNTS IN THE
INCH RANGE BUT IF WAVES END UP FORMING ALONG THE FRONTAL BOUNDARY
AND IT STALLS...THE NORTH TO SOUTH ORIENTATION OF THE SYSTEM WOULD
BE FAVORABLE FOR PICKING A GOOD BIT MORE RAIN. AGAIN AT MOMENT IT
DOES NOT LOOK LIKE THE FRONT WILL STALL BUT RATHER JUST SOMETHING TO
WATCH. COOLER AIR WILL SWING DOWN BEHIND THE FRONTAL MIDWEEK BUT
LOOKS FAR ENOUGH BEHIND THAT MOST OF THE LINGERING POST FRONTAL
SHOWERS WILL BE OVER WITH BY THEN.
&&
.AVIATION /17Z FRIDAY THROUGH TUESDAY/...
LOW LEVEL MOISTURE CONTINUES TO ADVECT FROM THE NORTH...AND WILL
KEEP THE TERMINALS ON THE CUSP OF MVFR CONDITIONS. EXPECT CLEARING
THIS EVENING AND EARLY TONIGHT...AND COULD SEE SOME MVFR MIST
DEVELOPING OVER THE NORTHEAST MOUNTAIN VALLEYS LATE TONIGHT.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z SATURDAY...
FORECAST CONFIDENCE...HIGH.
ALTERNATE SCENARIOS: UNCERTAINTY IN DEVELOPMENT OF MVFR MIST
TONIGHT.
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 18 19 20 21 22 23 00 01 02 03 04 05
EST 1HRLY 13 14 15 16 17 18 19 20 21 22 23 00
CRW CONSISTENCY M M M M M M M M M M M M
HTS CONSISTENCY M M M M M M M M H H M H
BKW CONSISTENCY H M M H M H H H H H H H
EKN CONSISTENCY H H H H H H H H M M M M
PKB CONSISTENCY M M M M M M M M M M M M
CKB CONSISTENCY H H H M M M M M M M M M
AFTER 18Z SATURDAY...
IFR POSSIBLE IN RAIN SHOWERS MONDAY INTO MONDAY NIGHT.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...TRM/SL
NEAR TERM...SL/26
SHORT TERM...TRM
LONG TERM...JR
AVIATION...26
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
1035 AM MST FRI MAR 8 2013
.UPDATE...
ISSUED AT 853 AM MST FRI MAR 8 2013
15Z SURFACE ANALYSIS HAD A WEAK COLD FRONT ACROSS MT INTO SOUTHERN
ND. WATER VAPOUR HAD LARGE UPPER TROUGH WITH UPPER LOW DIGGING
INTO SOUTHERN CA. SOUTHWEST FLOW ALOFT AHEAD OF SYSTEM PRODUCING
STREAM OF MID/HIGH CLOUDS OVER THE CWA. EMBEDDED SHORTWAVE OVER
SOUTHEAST MT...UNDER RIGHT ENTRANCE REGION OF 90KT JET...PRODUCING
SOME WEAK RADAR RETURNS OVER NORTHWEST SD. AREA ALSO IN A REGION OF
WEAK LOW LEVEL FRONTOGENESIS...WHICH SHOULD PERSIST MOST OF THE
DAY PER 12Z RAP AND THUS WILL CONTINUE LOW POPS IN FAR NORTHWEST
PORTIONS OF CWA. PRESSURE FALLS OVER EASTERN WY/MT SUPPORTING
EAST/SOUTHEAST LOW LEVEL FLOW AND SOME FOG OVER PORTIONS OF
CENTRAL SD. FOG SHOULD MIX AWAY SOME BY EARLY AFTERNOON...SO HAVE
EXPANDED AND EXTENDED CURRENT AREA OF FOG TO COVER SOUTHEAST
THIRD OF THE CWA.
FINALLY...12Z NAM CONTINUES TREND OF FASTER NORTHERN STREAM
TROUGH...WHICH WILL PUSH CA TROUGH FURTHER SOUTH AND EAST OF CWA.
HAVE ADJUSTED POPS TO MATCH SLOWER ONSET OF PRECIPITATION THIS
EVENING.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY NIGHT)
ISSUED AT 351 AM MST FRI MAR 8 2013
DIGGING SW CONUS UPPER TROUGH WILL EJECT TOWARD THE
REGION IN THE PERIOD AND SUPPORT CYCLOGENESIS OVER THE CENTRAL PLAINS.
MEANWHILE A FAST MOVING NORTHERN STREAM TROUGH WILL DROP INTO THE
NORTHERN PLAINS JUST AHEAD OF THE SW CONUS TROUGH...EVENTUALLY
PHASING EAST OF THE REGION. FORECAST MODELS HAVE STRUGGLED WITH
FORECAST DETAILS FOR THE LAST SEVERAL RUNS...KEEPING THE TRACK WELL
SOUTH OF THE FA AT FIRST/THEN SHIFTING THE TRACK NW FOR SEVERAL
CYCLES /WITH THE LATEST SUITE SUPPORTING A SHIFT BACK TO THE SOUTH.
THE EXACT TRACK WILL HINGE UPON TWO MAIN FEATURES: 1/ HOW FAST THE
NORTHERN STREAM TROUGH PROPAGATES INTO THE NORTHERN PLAINS AHEAD OF
THE EJECTING SW CONUS UPPER TROUGH. 2/ THE INTENSITY OF THE FORWARD
FLANK JET STREAK WHICH WILL DETERMINE THE DEGREE OF POSITIVE TROUGH
TILT AND ASSOCIATED SHEARING OF THE THE SW CONUS UPPER WAVE...HIGHLY
AFFECTING THE SPEED AND LIFT PLACEMENT. CURRENT TRENDS SUPPORT A
STRONGER POSITIVE TILT TO THE SW CONUS UPPER WAVE...WITH A
ASSOCIATED FASTER PROPAGATION SPEED...BRINGING IN A VERSION OF
STRONGER SUBSIDENCE...WITH ASSOCIATED LL DRYING OVER MUCH OF THE
WESTERN 2/3 OF THE FA SAT. IN ADDITION..LL THERMAL FIELDS HAVE
TRENDED SLIGHTLY WARMER IN THE LATEST CONSENSUS BLEND...WITH MANY
LOCATIONS EXPECTED TO BE WELL IN THE 30S AND EVEN LOWER 40S ON
SAT...SAVE FAR SOUTH CENTRAL WHERE THE STRONGER COLLOCATION OF DEEP
LAYER LIFT WILL BE PRESENT. THE POTENTIAL FOR MIXED PRECIP WITH A
PERIOD OF FREEZING RAIN EXISTS OVER SCENTRAL LATE TONIGHT INTO SAT
MORNING...ALTHOUGH AS STATED EARLIER...FORECAST MODELS HAVE TERNED
WARMER PER THERMAL FIELDS...WITH LOCATIONS INVOF ICR REMAINING ABOVE
FREEZING UNTIL SAT MORNING. ACCUMULATING SNOWFALL LOOKS TO REMAIN
CONFINED TO THE FAR SOUTH AND SCENTRAL FA...WITH STRONG INDICATIONS
REMAIN FOR POTENTIAL DEFORMATION BANDING OVER FAR SCENTRAL SAT
AFTERNOON...A SOLUTION INDICATED IN NAM/GFS/SREF/AND ECMWF
SOLUTIONS. QUESTION REMAINS THROUGH WHERE AND THIS BAND WILL SETUP
AND THE DEGREE OF LL MOISTURE IN PLACE WHEN THE STRONGEST ROUND OF
DEEP ASCENT DEVELOPS IN THAT LOCATION.
LINGERING WEAK WAA/DEFORMATION ZONE WILL CONTINUE TO SHIFT NORTH OUT OF
THE FA THIS MORNING...WITH ONLY SMALL CHANCES FOR PRECIP GIVEN WEAK
FORCING AND DRY LL/S. OTHERWISE...THE NEXT ROUND OF STRONG WAA WILL
ENSUE THIS EVENING OVER SOUTHERN PORTIONS OF THE FA...SPREADING
NORTH OVERNIGHT. IT IS ENTIRELY POSSIBLE THAT THE MAJORITY OF PRECIP
MAY BE CONFINED TO THE FAR SE PORTION OF THE FA...WITH MUCH
UNCERTAINTY REMAINING PER THE DETAILS OF THE THIS FIRST ROUND OF WAA.
RETAINED A MIXED POTENTIAL FOR THIS IN SE...WITH GENERAL RAIN
CHANGING TO SNOW CHANCES ELSEWHERE. NORTHERN STREAM TROUGH WILL DIVE
IN THE NORTHERN PLAINS AND SUPPORT A ROUND OF LARGE SCALE SINK OVER
MUCH OF THE FA SAT...SUPPORTING LL DRYING OVER MUCH OF THE FA. DID
TREND POPS DOWN AND TO THE SOUTH GIVEN THIS CONCERN.
OTHERWISE...INCREASING LARGE SCALE ASCENT INDICATED IN Q-VECTOR
PROGS IS EXPECTED OVER THE SOUTHERN PORTIONS OF THE FA...MAINLY
SOUTH AND EAST OF A PINE RIDGE TO KADOKA LINE LATE SAT MORNING.
ASSOCIATED LIFT MAY CONTINUE TO SUPPORT MIXED PRECIP.
HOWEVER...DEEP AND STRONG ASCENT WILL LIKELY SUPPORT ENOUGH DYNAMIC
COOLING TO SUPPORT ALL SNOW OVER SCENTRAL AREAS BY MID MORNING.
OTHERWISE...THE REMAINDER THE FA MAY NOT SEE MUCH IN THE WAY OF
PRECIP GIVEN STRONG SINK AND DRYING LL/S. THIS INCLUDES THE NORTHERN
HILLS WHERE MOISTURE LOOKS TO BE LIMITED. THE NAM CERTAINLY DISPLAYS
A SHARP CUT OFF TO PRECIP IN QPF PROGS WHICH LOOKS HIGHLY CREDIBLE.
A RATHER WARM BL MAY LIMIT ACCUMS OVER PORTIONS OF THE SOUTHERN
FA...HOWEVER THE POTENTIAL FOR UP TO 4 INCHES REMAIN OVER THE FAR
SE...MELLETTE/TODD/TRIPP COUNTIES...WITH A LIKELY HEAVY WET LOWER
RATIO SNOW BEING FAVORED. TRIED TO INCORPORATED A SHIFT OF THE
HIGHEST POPS SE...LOWERING THE NW. WILL CONTINUE THE SPS AS DETAILS
ARE STILL LACKING AND WARNING CRITERIA NOT EXPECTED. STRONG GUSTY NW
WINDS ARE ALSO EXPECTED SAT AFTERNOON...ESP ON THE EASTERN BH
FOOTHILLS. HOWEVER...WARM BL TEMPS ABOVE FREEZING MAY HIGHLY LIMIT
BLOWING SNOW POTENTIAL. UPPER TROUGH AND ASSOCIATED LIFT WILL
QUICKLY SHIFT EAST AND WANE OVER THE FA SAT EVENING...WITH ALL
PLACES DRY AFTER MIDNIGHT.
.LONG TERM...(SUNDAY THROUGH THURSDAY)
ISSUED AT 351 AM MST FRI MAR 8 2013
TEMPERATURES WILL GRADUALLY WARM INTO EARLY NEXT WEEK AS RIDGE
BUILDS OVER THE WESTERN CONUS. A VARIETY OF WEAK DISTURBANCES MOVING
THROUGH WILL BRING LOW PRECIP CHANCES TO PTNS OF THE AREA THROUGH
THE FIRST PART OF THE WEEK. RIDGE CONTINUES TO AMPLIFY OVER THE AREA
FOR THE LAST PART OF THE WORK WEEK BRINGING DRY CONDITIONS AND WARM
TEMPS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1035 AM MST FRI MAR 8 2013
ISOLD RAIN OR SNOW SHOWERS MAY LINGER OVER NORTHEAST WYOMING INTO
NORTHWEST SOUTH DAKOTA TODAY BRINGING LCL MVFR CIGS/VIS. FOR
TONIGHT...RAIN AND SNOW WILL DEVELOP OVER THE AREA...THEN
TRANSITIONING TO ALL SNOW. THE GREATEST CHANCES WILL BE OVER SOUTH
CENTRAL SOUTH DAKOTA WHERE SOME FREEZING RAIN MAY ALSO DEVELOP.
WIDESPREAD IFR CIGS WITH AREAS OF IFR VSBY ARE EXPECTED OVER MUCH OF
THE AREA THROUGH THE FORECAST PERIOD.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&
$$
UPDATE...HELGESON
SHORT TERM...JC
LONG TERM...77
AVIATION...13
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
1014 AM CST FRI MAR 8 2013
.UPDATE...
LEAD SHORTWAVE IS PRODUCING ISENTROPIC LIFT IN THE MID AND HIGH
LEVELS ACROSS NORTH TEXAS. A LAYER OF DRY AIR BETWEEN 600-800MB IS
CAUSING MOST OF THE PRECIPITATION TO EVAPORATE BEFORE REACHING THE
GROUND. SOME GRADUAL SATURATION WILL OCCUR THROUGH THE DAY
ALLOWING FOR SOME LIGHT RAIN OR SPRINKLES TO REACH THE GROUND.
HOWEVER ANY RAIN AMOUNTS WILL BE FAIRLY LIGHT. WILL DROP POPS TO
20 PERCENT FOR THE ENTIRE AREA TODAY AND TONIGHT. OTHERWISE HAVE
MADE SOME MINOR ADJUSTMENTS TO TODAYS HIGHS...MAINLY TO LOWER THEM
DUE TO THE PERSISTENT CLOUDY CONDITIONS. TR.92
&&
.AVIATION...
CHALLENGES FOR THE 12Z TAF SET INCLUDE CIG TRENDS BETWEEN MVFR AND
LOW VFR AND TIMING OF RAIN CHANCES WITH A LEAD DISTURBANCE THIS
AFTERNOON.
STRATO-CU IN THE MVFR/VERY LOW VFR RANGE HAS BEEN SURGING NORTH
ACROSS THE TERMINALS IN ADVANCE OF A LEAD SHORTWAVE DISTURBANCE
ROTATING NORTHEAST OUT OF OLD MEXICO AND THE RIO GRANDE VALLEY.
THOUGH THERE MAY BE A BRIEF WINDOW FOR LOW VFR CIGS BETWEEN
030-040 THIS MORNING...WILL LEAN WITH MODEL BUFR AND RUC OPS40
SOUNDINGS WITH GOING WITH A PREVAILING MVFR AROUND 025...BUT WITH
A TEMPO GROUP FOR LOW MVFR CIGS BETWEEN 015-020 THROUGH LATE
MORNING.
ISENTROPIC ASCENT THIS AFTERNOON SHOULD HELP TOP-DOWN COLUMN
SATURATION OCCUR QUICKLY AND SOME -RA/-SHRA OCCURRING BETWEEN 21Z
AND 01Z. HAVE INTRODUCED A PROB30 GROUP TO COVER THIS VERY LIGHT
RAINFALL THAT IS EXPECTED THIS AFTERNOON. THE LEAD SHORTWAVE EXITS
TO THE NORTHEAST EARLY THIS EVENING WITH A BRIEF WINDOW FOR CIGS
IMPROVING TO LOW VFR ONCE AGAIN...BEFORE RETURNING TO THE MVFR
CATEGORY BY MIDNIGHT AND BEYOND. SOUTHEAST WINDS 10-15 KTS WILL
CONTINUE THROUGHOUT THE FORECAST.
OUTLOOK...
MODELS HAVE SPED UP TIMING OF DRYLINE/FRONT IN ADVANCE OF OUR MAIN
SYSTEM ROTATING SOUTHEAST CURRENTLY OVER SRN CA/WRN AZ. IT APPEARS
THE MAIN WINDOW FOR +TSRA WILL BE 21Z-03Z SATURDAY WITH WINDS SHIFTING
NORTHWEST AND VERY GUSTY BEHIND THE COLD FRONT BY 12Z SUNDAY.
05/
&&
.PREV DISCUSSION... /ISSUED 313 AM CST FRI MAR 8 2013/
0UR NEXT UPPER STORM SYSTEM WILL BE MOVING INTO SOUTHERN CALIFORNIA
THIS MORNING WITH CYCLOGENESIS UNDERWAY ALONG THE FRONT RANGE OF
COLORADO. THE UPPER LOW WILL MOVE REACH THE 4-CORNERS SATURDAY
MORNING AND KANSAS BY SATURDAY EVENING. A TROUGH EXTENSION WILL
HANG BACK INTO SOUTHERN ARIZONA AS THE MAIN UPPER LOW CONTINUES
INTO THE MIDWEST. SATURDAY THROUGH SATURDAY NIGHT...THE 300MB JET
WILL BE INCREASING FROM LESS THAN 60 KNOTS IN THE MORNING TO
90-100KTS IN THE EVENING WHICH WILL HELP TO INCREASE 0-6KM BULK
SHEAR INTO THE 60-70 KNOTS RANGE. BEST CAPE VALUES...300-600
J/KG...WILL OCCUR OVER THE SOUTHWEST AND WESTERN COUNTIES SATURDAY
AFTERNOON WHICH SHOULD BE WHERE THE STRONGEST...POSSIBLY SEVERE...
STORMS OCCUR WITH THIS SYSTEM LATE SATURDAY AFTERNOON. ALTHOUGH
SHEAR REMAINS HIGH SATURDAY EVENING AND OVERNIGHT...WEAKENING
INSTABILITY AND MID LEVEL LAPSE RATES SHOULD RESULT IN A
DIMINISHED CHANCE OF SEVERE STORMS BY MID EVENING SATURDAY.
AS THE PACIFIC PUSHES THROUGH THE CWA SATURDAY NIGHT...THE LINE
OF STORMS COULD PRODUCE RAINFALL OF 1/2 TO 1 INCH WITH THE
SOUTHEAST THIRD HAVING THE BEST CHANCE TO SEE 3/4 TO OVER 1 INCH
BEFORE ENDING.
ON SUNDAY...THE REMAINING UPPER TROUGH TO OUR WEST WILL SLIDE ACROSS
THE REGION...AND MAY PRODUCE SOME LIGHT RAIN FROM LINGERING MID
LEVEL MOISTURE...BUT AMOUNTS WILL BE LIGHT. COLDER AIR ARRIVES
BEHIND THE FRONT FOR THE FIRST OF THE WORK WEEK. THE WESTERN AND
NORTHERN AREAS MAY SEE A FREEZE ON TUESDAY MORNING. THE REST OF
NEXT WEEK WILL BE DRY WITH TEMPERATURES MODERATING TO ABOVE NORMAL.
75
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 65 57 69 50 58 / 20 20 40 80 20
WACO, TX 67 58 72 51 58 / 20 20 30 70 60
PARIS, TX 63 53 66 52 58 / 20 20 20 70 40
DENTON, TX 65 58 69 48 57 / 20 20 50 80 20
MCKINNEY, TX 64 56 67 49 58 / 20 20 30 80 30
DALLAS, TX 65 57 68 52 58 / 20 20 40 80 30
TERRELL, TX 65 55 68 53 58 / 20 20 20 70 40
CORSICANA, TX 67 57 69 55 59 / 20 20 20 70 60
TEMPLE, TX 67 59 72 53 59 / 20 20 30 70 70
MINERAL WELLS, TX 66 59 72 47 57 / 20 20 50 60 20
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$