Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 02/23/13
AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
930 AM PST THU FEB 21 2013
.SYNOPSIS...
NORTHERLY FLOW ALOFT WILL CONTINUE ACROSS THE REGION THROUGH
SATURDAY AND RESULT IN ONLY A SLIGHT WARMING TREND. A WEAK
DISTURBANCE WILL PRODUCE SCATTERED LIGHT SHOWERS TODAY INTO THIS
EVENING...WITH SHOWERS MOST COMMON IN THE MOUNTAINS. PATCHY FROST IS
EXPECTED IN THE VALLEYS TONIGHT. GUSTY WESTERLY WINDS ARE EXPECTED
IN THE MOUNTAINS AND DESERTS SATURDAY...THEN STRONGER NORTHEAST
WINDS WILL DEVELOP THROUGH AND BELOW PASSES AND CANYONS LATE
SATURDAY NIGHT AND SUNDAY AS ANOTHER UPPER-LEVEL TROUGH OF LOW
PRESSURE SLIDES SOUTHEAST THROUGH THE GREAT BASIN. MOSTLY SEASONAL
TEMPERATURES ARE EXPECTED EARLY NEXT WEEK UNDER NORTHWEST FLOW.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
A FEW SHOWERS WERE OCCURRING THIS MORNING AHEAD OF A SHORTWAVE
MOVING SOUTHEAST THROUGH CENTRAL CALIFORNIA. SOME DENSE FOG WAS
OCCURRING OVER THE MOUNTAINS WHERE THE CLOUDS WERE INTERSECTING THE
TERRAIN...MOSTLY ABOVE 4000 FEET ABOVE SEA LEVEL. EXPECT SOME MORE
SHOWERS TODAY AS HIGH-RES MODELS SUCH AS THE HRRR AND LOCAL WRF ARE
SHOWING SCATTERED LIGHT PRECIP AND MODERATELY HIGH RH MOSTLY BELOW
700 MB. SNOW LEVELS WILL BE RISING TO ABOUT 5000 FEET DURING THE
AFTERNOON. PRECIP SHOULD END NORTH TO SOUTH LATE TODAY/EARLY THIS
EVENING...AND MOST AREAS SHOULD CLEAR BY LATE TONIGHT. WHILE LOCALLY
GUSTY WINDS ARE PROGGED THROUGH/BELOW N-S/NE-SW ORIENTED
PASSES/CANYONS SUCH AS CAJON PASS AND IN THE SANTA ANA MTNS
TONIGHT/EARLY FRI...GUST POTENTIAL IS AROUND 40 MPH AT 12Z/4
AM...AND MOSTLY AT HIGHER ELEVATIONS...SO NO WIND ADVISORY WILL BE
ISSUED. A FROST ADVISORY MIGHT BE NEEDED IN THE VALLEYS TONIGHT AS
MOST VALLEY FLOORS WILL HAVE LITTLE/NO WIND AND CLEAR SKIES UNDER
THE COLD AIR MASS WITH 850 MB TEMPS STILL AROUND 3-4 DEG C. WILL
EVALUATE FOR THE AFTERNOON PACKAGE.
N/NW FLOW ALOFT WILL CONTINUE THROUGH SATURDAY AND RESULT IN ONLY A
SLOW WARMING TREND...WITH TEMPS REMAINING BELOW NORMAL. A GULF OF
ALASKA TROUGH WILL MOVE THROUGH THE PAC NW FRI NIGHT AND THROUGH
UTAH SAT NIGHT. TEMP GRADIENTS WILL INCREASE IN THE 850-700 MB
LAYER...AND 12Z NAM SHOWS 40-KNOT WINDS AT 850 MB...DOWN A BIT FROM
THE PREVIOUS RUN...AND ABOUT A 16-MB SURFACE PRESSURE GRADIENT FROM
NE NEVADA TO SAN DIEGO. HENCE...LOOKS LIKE SOME DECENT NE WINDS
THROUGH/BELOW PASSES AND CANYONS...WITH POSSIBLE GUSTS OVER 55
MPH...MAINLY INLAND EMPIRE/SANTA ANA MTNS/SAN DIEGO COUNTY MTNS. THE
OFFSHORE FLOW SHOULD FINALLY BRING SOME WARMING W OF THE MTNS. THE
NEXT INSIDE-SLIDER TROUGH FOR TUESDAY LOOKS MUCH WEAKER AND FURTHER
NE THAN MODEL SOLUTIONS FROM YESTERDAY...INCLUDING IN MOST OF THE
ENSEMBLE RUNS. HENCE...GENERALLY FAIR WEATHER WITH SEASONAL TEMPS
THEN.
&&
.AVIATION...
211600Z...A WEAK COASTAL EDDY WILL CONTINUE SCT-BKN LOW CLOUDS ALONG
THE COAST AND IN THE INLAND VALLEYS THROUGH THIS MORNING...WITH BASES
BETWEEN 2500 AND 3500 FT MSL AND TOPS TO 5000 TO FT MSL. A WEAK
WEATHER DISTURBANCE MOVING OVER THE AREA THIS AFTERNOON WILL BRING
ISOLATED LIGHT SHOWERS OVER AND WEST OF THE MOUNTAINS...MOSTLY
CONFINED TO SAN DIEGO COUNTY. HOWEVER...HAVE OPTED TO KEEP KSAN TAF
FEW/SCT040 WITH CONFIDENCE TOO LOW TO INCLUDE ANY PRECIPITATION.
CLOUD COVER WILL BE DECREASING OVERNIGHT OVER ALL AREAS.
&&
.MARINE...
THE SMALL CRAFT ADVISORY FOR THE OUTER COASTAL WATERS HAS BEEN
ALLOWED TO EXPIRE. HOWEVER...COMBINED SEAS OF 7 TO 9 FEET ARE
EXPECTED THROUGH LATE THIS MORNING...AS WINDS CONTINUE TO DIMINISH.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
PUBLIC...MAXWELL
AVIATION/MARINE...JT
AREA FORECAST DISCUSSION...UPDATE
NWS SAN DIEGO CA
525 AM PST THU FEB 21 2013
.SYNOPSIS...
A COOL NORTHERLY FLOW WILL CONTINUE ACROSS THE REGION INTO THE
WEEKEND. A WEAK DISTURBANCE MAY PRODUCE A FEW LIGHT SHOWERS TODAY
AND TONIGHT...OTHERWISE IT WILL BE PARTLY CLOUDY AND SLIGHTLY
WARMER. QUITE COOL AGAIN TONIGHT WITH PATCHY FROST POSSIBLE AGAIN IN
THE VALLEYS. GUSTY ONSHORE WIND SATURDAY WILL TURN OFFSHORE AND
BECOME GUSTY THROUGH AND BELOW PASSES AND CANYONS LATE SATURDAY
NIGHT AND SUNDAY AS ANOTHER UPPER-LEVEL TROUGH SLIDES SOUTHEAST
THROUGH THE GREAT BASIN. SEASONAL TEMPS AND DRY NEXT WEEK UNDER
NORTHWEST FLOW ALOFT.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
A FEW LOW CLOUDS WERE DEVELOPING EARLY THIS MORNING OVER COASTAL
AREAS...OTHERWISE SKIES WERE MOSTLY CLEAR. WINDS WERE MOSTLY
LIGHT...EXCEPT IN SOME MOUNTAIN AND DESERT AREAS WHERE THEY WERE
LOCALLY 15 TO 25 MPH.
AN UPPER-LEVEL HIGH WAS CENTERED OVER THE PACIFIC NEAR 160W...WHILE
A BROAD TROUGH COVERED THE WESTERN U.S. A SHORT-WAVE TROUGH WILL
DIVE SOUTH ACROSS CA TODAY...INCREASING CLOUDS AND BRINGING A CHANCE
FOR MORE LIGHT SNOW AND RAIN SHOWERS. BEST CHANCE FOR ACCUMULATIONS
WILL BE IN THE MOUNTAINS. THE WAVE IS WELL DEVELOPED ON WATER
VAPOR IMAGERY EARLY THIS MORNING NEAR THE NORTHERN CA BORDER. THIS
DISTURBANCE WILL EXIT THE REGION THIS EVENING...ALLOWING SKIES TO
CLEAR...SETTING US UP FOR ANOTHER CHILLY NIGHT.
ANOTHER...STRONGER WAVE WILL DIG SOUTH OVER THE WEEKEND. THIS ONE IS
WELL DEVELOPED ON SATELLITE IMAGERY NEAR THE BRITISH COLOMBIA COAST.
GLOBAL MODELS ALL DIG THE WAVE...BUT IT IS MOST AMPLIFIED ON THE 00Z
ECMWF/GEM MODELS. DEPENDING ON HOW STRONGLY IT DIGS...ONSHORE FLOW
MAY BECOME STRONG AND GUSTY OVER THE MTNS/DESERTS AGAIN ON SAT...
BEFORE TURNING BACK OFFSHORE AND BECOMING GUSTY THROUGH WND BELOW
THE OFFSHORE WIND PRONE PASSES AND CANYONS LATE SAT NIGHT AND SUN.
A DRY NW FLOW ALOFT AND MODERATING SURFACE FLOW SET THE STAGE FOR
FAIR AND SEASONAL WEATHER NEXT WEEK.
MAIN CONCERNS FOR THE NEXT FEW DAYS WILL BE THE CHANCE FOR SHOWERS
TODAY AND THIS EVENING...POSSIBLE FROST AGAIN TONIGHT...AND THE
UPCOMING ONSHORE...THEN OFFSHORE WINDS.
AT THIS TIME...WE WILL KEEP A CHANCE FOR SNOW/RAIN SHOWERS...MAINLY
SAN DIEGO COUNTY. 00Z ECMWF AND 06Z NAM BOTH SHOW SOME LIGHT
PRECIP...ALONG WITH THE LATEST HRRR MODEL...MAINLY IN SAN DIEGO
COUNTY TODAY.
IN TERMS OF FROST...HEIGHTS/THICKNESS DO INCREASE A BIT AND THERE IS
SOME WIND IN THE WAKE OF THE SHORT-WAVE. THE 4-KM NAM SHOWS SOME SFC
WARMING AS WELL...SO WOULD EXPECT FROST TO REMAIN PATCHY...AND IN
THE WIND-SHELTERED SPOTS.
BASED ON A BLEND OF GUIDANCE...EXPECT BOTH THE ONSHORE AND THE
OFFSHORE WINDS WILL BE AT OR BELOW ADVISORY STRENGTH IN THE WIND
PRONE FOOTHILL/MTN/DESERT AREAS...BUT WILL MONITOR. IF THE LATEST
RUNS OF THE ECMWF MODEL WERE TO VERIFY...THEY WOULD BE STRONGER.
BUT GIVEN THE ECMWF PERFORMANCE THIS SEASON WITH THESE SHORT-WAVES
IN NW FLOW...COULD WELL SEE SUBSEQUENT RUNS EASE OFF ON THIS MORE
WESTWARD TRACK.
&&
.AVIATION...
211000Z...A WEAK COASTAL EDDY WILL CONTINUE SCT-BKN LOW CLOUDS ALONG
THE COAST THROUGH THIS MORNING...WITH BASES AROUND 3000 FT MSL AND
TOPS TO 5000 FT MSL. PATCHY STRATUS WILL PENETRATE 25 TO 30 SM
INLAND BY MID THIS MORNING. SKC AND P6SM VIS ARE FORECAST THIS AFTN
THROUGH THE REMAINDER OF THE TAF PERIOD. ISOLATED SHOWERS POSSIBLE
THROUGH THIS EVENING BUT LITTLE AVIATION IMPACT EXPECTED.
&&
.MARINE...
THE SMALL CRAFT ADVISORY FOR THE OUTER COASTAL WATERS HAS BEEN
EXTENDED THROUGH 8 AM PST THIS MORNING DUE TO COMBINED SEAS
REMAINING ABOVE 10 FEET. SEAS WILL LOWER THROUGH THE MORNING AS THE
WIND CONTINUES TO DIMINISH.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...SMALL CRAFT ADVISORY UNTIL 8 AM PST THURSDAY FOR THE OUTER
WATERS AND INCLUDING SAN CLEMENTE ISLAND.
&&
$$
PUBLIC...JAD
AVIATION/MARINE...JJT
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
1051 PM EST FRI FEB 22 2013
.SYNOPSIS...
A WARM FRONT IS EXPECTED TO LIFT NORTHWARD INTO SOUTHEAST GEORGIA
THROUGH TONIGHT AS A WEDGE OF HIGH PRESSURE ANCHORS OVER THE
CAROLINAS. A WAVE OF LOW PRESSURE WILL DEVELOP ALONG THE FRONT ON
SATURDAY THEN PUSH NORTHEAST. HIGH PRESSURE WILL BRIEFLY RETURN TO
THE AREA ON SUNDAY BEFORE A WARM FRONT LIFTS NORTH ACROSS THE AREA
LATE MONDAY AND MONDAY NIGHT....FOLLOWED BY THE PASSAGE OF A COLD
FRONT EARLY TUESDAY. DRIER CONDITIONS ARE EXPECTED TO RETURN TO THE
REGION BY THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
WILL ALLOW DENSE FOG ADVISORY TO EXPIRE AT 11 PM. VSBYS IN THE FOG
ARE IMPROVING AS RAIN INTENSIFIES. THE FOG IS BECOMING RATHER
THICK IN THE CHARLESTON METRO AREA...BUT AGAIN...EXPECT THIS TO BE
TEMPORARY AS RAIN FILLS IN FROM THE SOUTHWEST.
AT 23/02Z...THE WEDGE FRONT EXTENDING ROUGHLY ALONG A CAPE ROMAIN-
HILTON HEAD-RICHMOND HILL-JESUP LINE. THE FRONT WILL MEANDER
ALONG THE COAST FOR MUCH OF THE NIGHT BEFORE BUCKLING NORTH
SLIGHTLY AS A WAVE OF LOW PRESSURE DEVELOPS ALONG IT. THE PRIMARY
FORECAST CONCERNS THROUGH SUNRISE CENTER ON TEMPERATURES AS WELL
AS THE POTENTIAL FOR HEAVY RAIN AND DENSE FOG.
HEAVY RAIN...WATER VAPOR IMAGERY SHOWS A SHORTWAVE OVER FAR
SOUTHEAST ALABAMA AND THE WESTERN FLORIDA PANHANDLE MOVING
NORTHEAST. UPPER FORCING IS SLOWLY INCREASING AHEAD OF THIS
FEATURE AS THE UPPER LEVEL FLOW BECOMES INCREASING MORE DIFLUENT
ACROSS THE SOUTHEAST U.S. IN RESPONSE TO THE DIGGING LONG-WAVE
TROUGH NOTED OVER THE CENTRAL/SOUTHERN PLAINS. CLOUD TOPS ARE
SLOWLY COOLING OVER SOUTHERN GEORGIA AND NORTHERN FLORIDA IN
RESPONSE WITH THE COVERAGE OF RAIN STEADILY EXPANDING/INTENSIFYING
TO THE SOUTHWEST PER KVAX/KTLH RADAR COMPOSITES. RAIN IS EXPECTED
TO OVERSPREAD MUCH OF THE FORECAST AREA AS THE SHORTWAVE
APPROACHING SOUTHERN GEORGIA DRAWS CLOSER. PWATS IN EXCESS OF 1.5
INCHES /NEAR THE 99TH PERCENTILE FOR LATE FEBRUARY/ WILL SUPPORT
MODERATE TO OCCASIONALLY HEAVY RAIN AT TIMES...BUT DO NOT
ANTICIPATE ANY WIDESPREAD PROBLEMS WITH FLASH FLOODING. THE LATEST
RUNS OF THE HIGHER RESOLUTION SHORT TERM MODELS INCLUDING THE RAP
AND H3R ARE IN GOOD AGREEMENT IN SHOWING THE WEDGE FRONT
MEANDERING VERY CLOSE TO THE COAST FOR A GOOD PORTION OF THE NIGHT
AND ARE NOW FOCUSING THE AXIS OF HEAVIEST RAINS OVER SOUTHEAST
SOUTH CAROLINA AND SOUTHEAST GEORGIA THROUGH SUNRISE. WILL ADJUST
FIRST PERIOD POPS TO NEAR 100 PERCENT FOR ALL AREAS...INCREASE QPF
SLIGHTLY AND INCLUDE A RAIN HEAVY AT TIMES QUALIFIER. THE RISK FOR
TSTMS AT THIS POINT LOOKS LOW...ALTHOUGH A RUMBLE OR TWO CAN NOT
BE COMPLETELY RULED OUT.
TEMPERATURES...PINNING DOWN TEMPERATURES IS PROVING TO BE NEAR
IMPOSSIBLE. THE LATEST RAP SUGGESTS THE WEDGE FRONT WILL DRIFT
SLIGHTLY EAST OVER THE NEXT FEW HOURS...POSSIBLY EMERGING OFF THE
LOWER SOUTH CAROLINA COAST. WINDS HAVE RECENTLY TURNED NORTH AT
THE CHARLESTON AIRPORT WHICH AGREES WELL WITH THE RAP WIND FIELDS.
HAVE ADJUSTED HOURLY TEMPERATURES TO BETTER MATCH THE REPOSITIONING
OF THE WEDGE FRONT THROUGH SUNRISE. ALSO LOWERED LOW TEMPERATURES
DOWN QUITE A BIT IN SOME AREAS AS SOME LOCALES WELL INLAND WERE
ALREADY BELOW FORECASTED MINIMUMS. COULD VERY WELL SEE A HUGE
SWING IN TEMPERATURES...ESPECIALLY AT THE COAST... SHOULD THE WARM
FRONT PUSHING BACK INLAND QUICKER THAN EXPECTED. LOWS WILL RANGE
FROM THE LOWER 40S WELL INLAND TO AROUND 60 IN THE LUDOWICI-
DARIEN-HINESVILLE CORRIDOR...BUT THIS IS A HIGHLY UNCERTAIN
FORECAST.
DENSE FOG...DENSE FOG REMAINS A PROBLEM ACROSS INTERIOR SOUTHEAST
GEORGIA NORTH OF THE WEDGE FRONT AND ACROSS CHATHAM COUNTY WHERE
SEA FOG LINGERS. EXTENDED THE DENSE FOG ADVISORY UNTIL 11 PM AS
WARNING POINTS ARE STILL REPORTING VSBYS NEAR ZERO AT TIMES. VSBYS
ARE IMPROVING A BIT WHERE RAIN FALLS SO ANTICIPATE THE ADVISORY
WILL BE ALLOWED TO EXPIRE AT 11 PM.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/...
SATURDAY AND SATURDAY NIGHT...A VERY LOW CONFIDENCE FORECAST TO
START THE WEEKEND. A WEDGE FRONT WILL LIKELY BE POSITIONED SOMEWHERE
ACROSS NORTHWEST PORTIONS OF THE FORECAST AREA AT THE START OF THE
DAY AS A WAVE OF LOW PRESSURE DEVELOPS IN THE VICINITY OF CENTRAL
GEORGIA. THE LOW WILL TRACK ALONG THE WEDGE FRONT THROUGH THE DAY
AND SHIFT NORTHEAST OF THE AREA IN THE EVENING AS A TRAILING COLD
FRONT SWINGS THROUGH FROM THE NORTHWEST.
SHOWERS ARE EXPECTED TO BE ONGOING IN THE MORNING ACROSS NORTHWEST
PORTIONS OF THE AREA...WITH THE GREATEST COVERAGE TOWARD THE
MIDLANDS AND EAST-CENTRAL GEORGIA...AS A DISTURBANCE APPROACHES
ALOFT AND ISENTROPIC LIFT STRENGTHENS. SOME SHOWERS SHOULD ALSO BE
STREAMING INTO COASTAL SOUTH CAROLINA FROM THE ADJACENT COASTAL
WATERS. THE BAND OF SHOWERS OVER THE MIDLANDS AND EAST-CENTRAL
GEORGIA SHOULD SHIFT SOUTHEAST OVER THE AREA DURING THE AFTERNOON
AND EARLY EVENING AS THE WAVE OF LOW PRESSURE PASSES...EVENTUALLY
TAPERING OFF OVERNIGHT AS THE TRAILING COLD FRONT PUSHES OFFSHORE.
WITH PRECIPITABLE WATER VALUES AROUND 1.5 INCHES...OR NEARLY 2
STANDARD DEVIATIONS ABOVE NORMAL...THE RAIN COULD BE HEAVY AT TIMES.
THERE IS A POTENTIAL FOR SOME ISOLATED THUNDERSTORMS MAINLY IN THE
AFTERNOON IN THE WARM SECTOR...WHICH SHOULD BE OVER PARTS OF
SOUTHEAST GEORGIA AND COASTAL SOUTHEAST SOUTH CAROLINA.
TEMPERATURES WILL BE VERY DIFFICULT TO FORECAST...WITH A VERY LARGE
GRADIENT EXPECTED OVER THE AREA. WITH THE WEDGE EXPECTED TO PERSIST
ACROSS FAR NORTHWEST PORTIONS OF THE AREA HIGHS THERE ARE ONLY
FORECAST TO BE IN THE LOWER 50S...BUT WITHIN THE WARM SECTOR HIGHS
COULD BE IN THE LOWER TO MID 70S ACROSS NORTH COASTAL GEORGIA AND
AREAS CLOSER TO THE ALTAMAHA. PINNING DOWN THE EXACT POSITION OF THE
WEDGE IS SO DIFFICULT THAT TEMPERATURES IN SOME AREAS COULD BE OFF
BY AS MUCH AS 10 DEGREES FROM THE CURRENT FORECAST.
SUNDAY...HIGH PRESSURE WILL BRIEFLY BUILD OVER THE REGION FROM THE
NORTHWEST WITH RAIN-FREE CONDITIONS EXPECTED. TEMPERATURES COULD
REACH HIGHS AROUND 70 WITH A DOWNSLOPE WIND COMPONENT ALOFT UNDER
MOSTLY SUNNY TO PARTLY CLOUDY SKIES.
SUNDAY NIGHT AND MONDAY...A WARM FRONT EXTENDING FROM A STORM SYSTEM
OVER THE MID-MISSISSIPPI VALLEY WILL SLOWLY LIFT NORTHWARD TOWARD
THE AREA. IT APPEARS THE WARM FRONT COULD ENTER PARTS OF SOUTHEAST
GEORGIA LATE IN THE DAY ON MONDAY. STRENGTHENING ISENTROPIC ASCENT
AND DEEP MOISTURE AHEAD OF THE WARM FRONT SHOULD ALLOW SCATTERED TO
NUMEROUS SHOWERS TO DEVELOP FROM THE SOUTH SUNDAY NIGHT...THEN
BECOME NUMEROUS TO WIDESPREAD ACROSS THE AREA ON MONDAY. SOME
ISOLATED THUNDERSTORMS COULD ALSO DEVELOP ACROSS SOUTHERN AREAS
LATER IN THE DAY DEPENDING ON THE TIMING OF THE FRONT.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
WET CONDITIONS WILL PERSIST OVER THE FORECAST AREA THROUGH EARLY
NEXT WEEK AS A SFC LOW SHIFTS ACROSS THE SOUTHEAST. CONDITIONS WILL
THEN BEGIN TO DRY AS THE SFC LOW SHIFTS OFF THE MID ATLANTIC COAST
AND IS FOLLOWED BY HIGH PRESSURE OVER THE SOUTHEAST. A COOL AND DRY
TREND SHOULD THEN TAKE PLACE THROUGH MUCH OF NEXT WEEK AS A
MID/UPPER LVL LOW BECOMES CUT OFF OVER THE NORTHEASTERN UNITED
STATE. OVERALL...AFTERNOON HIGHS WILL RANGE FROM THE MID 60S ON
TUESDAY TO THE UPPER 50S BY THURSDAY. OVERNIGHT LOWS WILL RANGE FROM
THE UPPER 30S/LOWER 40S ON TUESDAY TO MID 30S/LOWER 40S BY THURSDAY.
&&
.AVIATION /04Z SATURDAY THROUGH WEDNESDAY/...
BOTH TERMINALS WILL BE IFR OR LOWER FOR MOST OF THE NIGHT AS MORE
DEEP MOISTURE CONTINUES ITS TRACK UP THE COAST. DEGRADED
VISIBILITIES DUE TO FOG AND RAIN ARE ALSO A POSSIBILITY AS THE WARM
FRONT AND MINOR SHORTWAVE IMPULSES MOVE UP INTO THE AREA.
CONDITIONS LOOK TO SLIGHTLY IMPROVE BY DAYBREAK AS THE WARM FRONT
LIFTS NORTH OF KSAV AND WIND SPEEDS PICK UP...HOWEVER...MODEL
SOUNDINGS ARE KEEPING THE DEEP MOISTURE IN PLACE FOR THE DAY.
EXTENDED AVIATION OUTLOOK...MVFR OR LOWER CONDITIONS WILL LIKELY
CONTINUE THROUGH SATURDAY NIGHT DUE TO LOW CEILINGS AND REDUCED
VISIBILITIES. VFR CONDITIONS WILL PREVAIL SUNDAY...THEN MVFR OR
LOWER CONDITIONS SHOULD RETURN SUNDAY NIGHT THROUGH MONDAY NIGHT.
VFR CONDITIONS WILL THEN PREVAIL TUESDAY INTO WEDNESDAY.
&&
.MARINE...
SAVANNAH PILOT BOAT REPORTED VSBYS NEAR ZERO IN DENSE SEA FOG AS
FAR OFFSHORE AS BUOY CHARLIE. HILTON HEAD AIRPORT ALSO REPORTING A
CEILING NEAR 100 FT SUGGESTING FOG IS LIKELY NOT TOO FAR OFFSHORE.
HAVE ISSUED A DENSE FOG ADVISORY FOR AMZ352-354 UNTIL 1 AM. ITS
UNCLEAR HOW MUCH VSBYS WILL IMPROVE AS RAIN FILLS IN...SO ONLY
TOOK THE ADVISORY UNTIL 1 AM. ADJUSTMENTS WILL BE NEEDED OVER THE
NEXT FEW HRS. ADJUSTED WINDS OVER THE SOUTH CAROLINA WATERS TO
NORTH OVERNIGHT AS RAP GUIDANCE SUGGESTS THE WEDGE FRONT WILL DROP
SOUTH. ALSO NUDGED THE START TIME FOR THE SMALL CRAFT ADVISORY TO
THE CURRENT TIME OVER THE GEORGIA OFFSHORE WATERS.
SATURDAY THROUGH TUESDAY...SMALL CRAFT ADVISORY CONDITIONS WILL
PERSIST OVER OUTER GEORGIA WATERS THROUGH 5 PM SATURDAY AS A WEDGE
OF HIGH PRESSURE INLAND MAINTAINS AN ENHANCED PRESSURE GRADIENT OVER
THESE WATERS THROUGH MUCH OF THE DAY AND SEAS REMAIN ELEVATED. THE
WEDGE WILL THEN BREAK DOWN LATE AS A SFC LOW TRACKS THROUGH THE
SOUTHEASTERN UNITED STATES AND INTO THE MID ATLANTIC. EXPECT
SOUTHERLY WINDS TO BECOME WEST AS A TRAILING COLD FRONT SHIFTS
THROUGH THE WATERS INTO EARLY SUNDAY. CONDITIONS WILL THEN REMAIN
BELOW SMALL CRAFT ADVISORY LEVELS FOR ALL WATERS THROUGH EARLY
MONDAY AS HIGH PRESSURE DOMINANTS THE PATTERN. WINDS AND SEAS WILL
THEN INCREASE MONDAY AFTERNOON INTO TUESDAY AS A WARM FRONT LIFTS
NORTH AND THEN IS FOLLOWED BY A SFC LOW TRACKING OVER THE WATERS
LATE. WE COULD SEE SMALL CRAFT ADVISORY CONDITIONS AS THE PRESSURE
GRADIENT BECOMES ENHANCED OVER THE WATERS DURING THIS TIME.
&&
.HYDROLOGY...
STORM TOTAL RAINFALL AMOUNTS OF 3-6 INCHES WITH LOCALLY HIGHER
AMOUNTS ARE LIKELY TO OCCUR ACROSS THE REGION THROUGH EARLY NEXT
WEEK BRINGING MORE RELIEF TO DROUGHT STRICKEN AREAS. THESE RAINS
FALLING INTO ALREADY SWOLLEN RIVERS WILL YIELD ADDITIONAL RISES
AND RIVERINE FLOODING THROUGH THE END OF NEXT WEEK. ADDITIONAL
RIVER FLOOD WARNINGS ARE LIKELY PER THE LATEST SHORT TERM ENSEMBLE
HYDROLOGIC FORECASTS AND RIVER GUIDANCE FROM THE SOUTHEAST RIVER
FORECAST CENTER.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...DENSE FOG ADVISORY UNTIL 1 AM EST SATURDAY FOR AMZ352-354.
SMALL CRAFT ADVISORY UNTIL 5 PM EST SATURDAY FOR AMZ374.
&&
$$
ST/BDC
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
954 PM EST FRI FEB 22 2013
.SYNOPSIS...
A WARM FRONT IS EXPECTED TO LIFT NORTHWARD INTO SOUTHEAST GEORGIA
THROUGH TONIGHT AS A WEDGE OF HIGH PRESSURE ANCHORS OVER THE
CAROLINAS. A WAVE OF LOW PRESSURE WILL DEVELOP ALONG THE FRONT ON
SATURDAY THEN PUSH NORTHEAST. HIGH PRESSURE WILL BRIEFLY RETURN TO
THE AREA ON SUNDAY BEFORE A WARM FRONT LIFTS NORTH ACROSS THE AREA
LATE MONDAY AND MONDAY NIGHT....FOLLOWED BY THE PASSAGE OF A COLD
FRONT EARLY TUESDAY. DRIER CONDITIONS ARE EXPECTED TO RETURN TO THE
REGION BY THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
VERY FEW CHANGES WERE MADE TO THE GOING FORECAST EXCEPT TO EXTEND
THE DENSE FOG ADVISORY FOR ANOTHER HOUR. WARNING POINTS STILL
INDICATE VSBYS ARE QUITE LOW...NEAR ZERO AT TIMES. VSBYS SHOULD
IMPROVE OVER THE NEXT HOURS AS RAIN FILLS IN FROM THE SOUTHWEST.
AT 23/02Z...THE WEDGE FRONT EXTENDING ROUGHLY ALONG A CAPE ROMAIN-
HILTON HEAD-RICHMOND HILL-JESUP LINE. THE FRONT WILL MEANDER
ALONG THE COAST FOR MUCH OF THE NIGHT BEFORE BUCKLING NORTH
SLIGHTLY AS A WAVE OF LOW PRESSURE DEVELOPS ALONG IT. THE PRIMARY
FORECAST CONCERNS THROUGH SUNRISE CENTER ON TEMPERATURES AS WELL
AS THE POTENTIAL FOR HEAVY RAIN AND DENSE FOG.
HEAVY RAIN...WATER VAPOR IMAGERY SHOWS A SHORTWAVE OVER FAR
SOUTHEAST ALABAMA AND THE WESTERN FLORIDA PANHANDLE MOVING
NORTHEAST. UPPER FORCING IS SLOWLY INCREASING AHEAD OF THIS
FEATURE AS THE UPPER LEVEL FLOW BECOMES INCREASING MORE DIFLUENT
ACROSS THE SOUTHEAST U.S. IN RESPONSE TO THE DIGGING LONG-WAVE
TROUGH NOTED OVER THE CENTRAL/SOUTHERN PLAINS. CLOUD TOPS ARE
SLOWLY COOLING OVER SOUTHERN GEORGIA AND NORTHERN FLORIDA IN
RESPONSE WITH THE COVERAGE OF RAIN STEADILY EXPANDING/INTENSIFYING
TO THE SOUTHWEST PER KVAX/KTLH RADAR COMPOSITES. RAIN IS EXPECTED
TO OVERSPREAD MUCH OF THE FORECAST AREA AS THE SHORTWAVE
APPROACHING SOUTHERN GEORGIA DRAWS CLOSER. PWATS IN EXCESS OF 1.5
INCHES /NEAR THE 99TH PERCENTILE FOR LATE FEBRUARY/ WILL SUPPORT
MODERATE TO OCCASIONALLY HEAVY RAIN AT TIMES...BUT DO NOT
ANTICIPATE ANY WIDESPREAD PROBLEMS WITH FLASH FLOODING. THE LATEST
RUNS OF THE HIGHER RESOLUTION SHORT TERM MODELS INCLUDING THE RAP
AND H3R ARE IN GOOD AGREEMENT IN SHOWING THE WEDGE FRONT
MEANDERING VERY CLOSE TO THE COAST FOR A GOOD PORTION OF THE NIGHT
AND ARE NOW FOCUSING THE AXIS OF HEAVIEST RAINS OVER SOUTHEAST
SOUTH CAROLINA AND SOUTHEAST GEORGIA THROUGH SUNRISE. WILL ADJUST
FIRST PERIOD POPS TO NEAR 100 PERCENT FOR ALL AREAS...INCREASE QPF
SLIGHTLY AND INCLUDE A RAIN HEAVY AT TIMES QUALIFIER. THE RISK FOR
TSTMS AT THIS POINT LOOKS LOW...ALTHOUGH A RUMBLE OR TWO CAN NOT
BE COMPLETELY RULED OUT.
TEMPERATURES...PINNING DOWN TEMPERATURES IS PROVING TO BE NEAR
IMPOSSIBLE. THE LATEST RAP SUGGESTS THE WEDGE FRONT WILL DRIFT
SLIGHTLY EAST OVER THE NEXT FEW HOURS...POSSIBLY EMERGING OFF THE
LOWER SOUTH CAROLINA COAST. WINDS HAVE RECENTLY TURNED NORTH AT
THE CHARLESTON AIRPORT WHICH AGREES WELL WITH THE RAP WIND FIELDS.
HAVE ADJUSTED HOURLY TEMPERATURES TO BETTER MATCH THE REPOSITIONING
OF THE WEDGE FRONT THROUGH SUNRISE. ALSO LOWERED LOW TEMPERATURES
DOWN QUITE A BIT IN SOME AREAS AS SOME LOCALES WELL INLAND WERE
ALREADY BELOW FORECASTED MINIMUMS. COULD VERY WELL SEE A HUGE
SWING IN TEMPERATURES...ESPECIALLY AT THE COAST... SHOULD THE WARM
FRONT PUSHING BACK INLAND QUICKER THAN EXPECTED. LOWS WILL RANGE
FROM THE LOWER 40S WELL INLAND TO AROUND 60 IN THE LUDOWICI-
DARIEN-HINESVILLE CORRIDOR...BUT THIS IS A HIGHLY UNCERTAIN
FORECAST.
DENSE FOG...DENSE FOG REMAINS A PROBLEM ACROSS INTERIOR SOUTHEAST
GEORGIA NORTH OF THE WEDGE FRONT AND ACROSS CHATHAM COUNTY WHERE
SEA FOG LINGERS. EXTENDED THE DENSE FOG ADVISORY UNTIL 11 PM AS
WARNING POINTS ARE STILL REPORTING VSBYS NEAR ZERO AT TIMES. VSBYS
ARE IMPROVING A BIT WHERE RAIN FALLS SO ANTICIPATE THE ADVISORY
WILL BE ALLOWED TO EXPIRE AT 11 PM.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/...
SATURDAY AND SATURDAY NIGHT...A VERY LOW CONFIDENCE FORECAST TO
START THE WEEKEND. A WEDGE FRONT WILL LIKELY BE POSITIONED SOMEWHERE
ACROSS NORTHWEST PORTIONS OF THE FORECAST AREA AT THE START OF THE
DAY AS A WAVE OF LOW PRESSURE DEVELOPS IN THE VICINITY OF CENTRAL
GEORGIA. THE LOW WILL TRACK ALONG THE WEDGE FRONT THROUGH THE DAY
AND SHIFT NORTHEAST OF THE AREA IN THE EVENING AS A TRAILING COLD
FRONT SWINGS THROUGH FROM THE NORTHWEST.
SHOWERS ARE EXPECTED TO BE ONGOING IN THE MORNING ACROSS NORTHWEST
PORTIONS OF THE AREA...WITH THE GREATEST COVERAGE TOWARD THE
MIDLANDS AND EAST-CENTRAL GEORGIA...AS A DISTURBANCE APPROACHES
ALOFT AND ISENTROPIC LIFT STRENGTHENS. SOME SHOWERS SHOULD ALSO BE
STREAMING INTO COASTAL SOUTH CAROLINA FROM THE ADJACENT COASTAL
WATERS. THE BAND OF SHOWERS OVER THE MIDLANDS AND EAST-CENTRAL
GEORGIA SHOULD SHIFT SOUTHEAST OVER THE AREA DURING THE AFTERNOON
AND EARLY EVENING AS THE WAVE OF LOW PRESSURE PASSES...EVENTUALLY
TAPERING OFF OVERNIGHT AS THE TRAILING COLD FRONT PUSHES OFFSHORE.
WITH PRECIPITABLE WATER VALUES AROUND 1.5 INCHES...OR NEARLY 2
STANDARD DEVIATIONS ABOVE NORMAL...THE RAIN COULD BE HEAVY AT TIMES.
THERE IS A POTENTIAL FOR SOME ISOLATED THUNDERSTORMS MAINLY IN THE
AFTERNOON IN THE WARM SECTOR...WHICH SHOULD BE OVER PARTS OF
SOUTHEAST GEORGIA AND COASTAL SOUTHEAST SOUTH CAROLINA.
TEMPERATURES WILL BE VERY DIFFICULT TO FORECAST...WITH A VERY LARGE
GRADIENT EXPECTED OVER THE AREA. WITH THE WEDGE EXPECTED TO PERSIST
ACROSS FAR NORTHWEST PORTIONS OF THE AREA HIGHS THERE ARE ONLY
FORECAST TO BE IN THE LOWER 50S...BUT WITHIN THE WARM SECTOR HIGHS
COULD BE IN THE LOWER TO MID 70S ACROSS NORTH COASTAL GEORGIA AND
AREAS CLOSER TO THE ALTAMAHA. PINNING DOWN THE EXACT POSITION OF THE
WEDGE IS SO DIFFICULT THAT TEMPERATURES IN SOME AREAS COULD BE OFF
BY AS MUCH AS 10 DEGREES FROM THE CURRENT FORECAST.
SUNDAY...HIGH PRESSURE WILL BRIEFLY BUILD OVER THE REGION FROM THE
NORTHWEST WITH RAIN-FREE CONDITIONS EXPECTED. TEMPERATURES COULD
REACH HIGHS AROUND 70 WITH A DOWNSLOPE WIND COMPONENT ALOFT UNDER
MOSTLY SUNNY TO PARTLY CLOUDY SKIES.
SUNDAY NIGHT AND MONDAY...A WARM FRONT EXTENDING FROM A STORM SYSTEM
OVER THE MID-MISSISSIPPI VALLEY WILL SLOWLY LIFT NORTHWARD TOWARD
THE AREA. IT APPEARS THE WARM FRONT COULD ENTER PARTS OF SOUTHEAST
GEORGIA LATE IN THE DAY ON MONDAY. STRENGTHENING ISENTROPIC ASCENT
AND DEEP MOISTURE AHEAD OF THE WARM FRONT SHOULD ALLOW SCATTERED TO
NUMEROUS SHOWERS TO DEVELOP FROM THE SOUTH SUNDAY NIGHT...THEN
BECOME NUMEROUS TO WIDESPREAD ACROSS THE AREA ON MONDAY. SOME
ISOLATED THUNDERSTORMS COULD ALSO DEVELOP ACROSS SOUTHERN AREAS
LATER IN THE DAY DEPENDING ON THE TIMING OF THE FRONT.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
WET CONDITIONS WILL PERSIST OVER THE FORECAST AREA THROUGH EARLY
NEXT WEEK AS A SFC LOW SHIFTS ACROSS THE SOUTHEAST. CONDITIONS WILL
THEN BEGIN TO DRY AS THE SFC LOW SHIFTS OFF THE MID ATLANTIC COAST
AND IS FOLLOWED BY HIGH PRESSURE OVER THE SOUTHEAST. A COOL AND DRY
TREND SHOULD THEN TAKE PLACE THROUGH MUCH OF NEXT WEEK AS A
MID/UPPER LVL LOW BECOMES CUT OFF OVER THE NORTHEASTERN UNITED
STATE. OVERALL...AFTERNOON HIGHS WILL RANGE FROM THE MID 60S ON
TUESDAY TO THE UPPER 50S BY THURSDAY. OVERNIGHT LOWS WILL RANGE FROM
THE UPPER 30S/LOWER 40S ON TUESDAY TO MID 30S/LOWER 40S BY THURSDAY.
&&
.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
BOTH TERMINALS WILL BE IFR OR LOWER FOR MOST OF THE NIGHT AS MORE
DEEP MOISTURE CONTINUES ITS TRACK UP THE COAST. DEGRADED
VISIBILITIES DUE TO FOG AND RAIN ARE ALSO A POSSIBILITY AS THE WARM
FRONT AND MINOR SHORTWAVE IMPULSES MOVE UP INTO THE AREA.
CONDITIONS LOOK TO SLIGHTLY IMPROVE BY DAYBREAK AS THE WARM FRONT
LIFTS NORTH OF KSAV AND WIND SPEEDS PICK UP...HOWEVER...MODEL
SOUNDINGS ARE KEEPING THE DEEP MOISTURE IN PLACE FOR THE DAY.
EXTENDED AVIATION OUTLOOK...MVFR OR LOWER CONDITIONS WILL LIKELY
CONTINUE THROUGH SATURDAY NIGHT DUE TO LOW CEILINGS AND REDUCED
VISIBILITIES. VFR CONDITIONS WILL PREVAIL SUNDAY...THEN MVFR OR
LOWER CONDITIONS SHOULD RETURN SUNDAY NIGHT THROUGH MONDAY NIGHT.
VFR CONDITIONS WILL THEN PREVAIL TUESDAY INTO WEDNESDAY.
&&
.MARINE...
SAVANNAH PILOT BOAT REPORTED VSBYS NEAR ZERO IN DENSE SEA FOG AS
FAR OFFSHORE AS BUOY CHARLIE. HILTON HEAD AIRPORT ALSO REPORTING A
CEILING NEAR 100 FT SUGGESTING FOG IS LIKELY NOT TOO FAR OFFSHORE.
HAVE ISSUED A DENSE FOG ADVISORY FOR AMZ352-354 UNTIL 1 AM. ITS
UNCLEAR HOW MUCH VSBYS WILL IMPROVE AS RAIN FILLS IN...SO ONLY
TOOK THE ADVISORY UNTIL 1 AM. ADJUSTMENTS WILL BE NEEDED OVER THE
NEXT FEW HRS. ADJUSTED WINDS OVER THE SOUTH CAROLINA WATERS TO
NORTH OVERNIGHT AS RAP GUIDANCE SUGGESTS THE WEDGE FRONT WILL DROP
SOUTH. ALSO NUDGED THE START TIME FOR THE SMALL CRAFT ADVISORY TO
THE CURRENT TIME OVER THE GEORGIA OFFSHORE WATERS.
SATURDAY THROUGH TUESDAY...SMALL CRAFT ADVISORY CONDITIONS WILL
PERSIST OVER OUTER GEORGIA WATERS THROUGH 5 PM SATURDAY AS A WEDGE
OF HIGH PRESSURE INLAND MAINTAINS AN ENHANCED PRESSURE GRADIENT OVER
THESE WATERS THROUGH MUCH OF THE DAY AND SEAS REMAIN ELEVATED. THE
WEDGE WILL THEN BREAK DOWN LATE AS A SFC LOW TRACKS THROUGH THE
SOUTHEASTERN UNITED STATES AND INTO THE MID ATLANTIC. EXPECT
SOUTHERLY WINDS TO BECOME WEST AS A TRAILING COLD FRONT SHIFTS
THROUGH THE WATERS INTO EARLY SUNDAY. CONDITIONS WILL THEN REMAIN
BELOW SMALL CRAFT ADVISORY LEVELS FOR ALL WATERS THROUGH EARLY
MONDAY AS HIGH PRESSURE DOMINANTS THE PATTERN. WINDS AND SEAS WILL
THEN INCREASE MONDAY AFTERNOON INTO TUESDAY AS A WARM FRONT LIFTS
NORTH AND THEN IS FOLLOWED BY A SFC LOW TRACKING OVER THE WATERS
LATE. WE COULD SEE SMALL CRAFT ADVISORY CONDITIONS AS THE PRESSURE
GRADIENT BECOMES ENHANCED OVER THE WATERS DURING THIS TIME.
&&
.HYDROLOGY...
STORM TOTAL RAINFALL AMOUNTS OF 3-6 INCHES WITH LOCALLY HIGHER
AMOUNTS ARE LIKELY TO OCCUR ACROSS THE REGION THROUGH EARLY NEXT
WEEK BRINGING MORE RELIEF TO DROUGHT STRICKEN AREAS. THESE RAINS
FALLING INTO ALREADY SWOLLEN RIVERS WILL YIELD ADDITIONAL RISES
AND RIVERINE FLOODING THROUGH THE END OF NEXT WEEK. ADDITIONAL
RIVER FLOOD WARNINGS ARE LIKELY PER THE LATEST SHORT TERM ENSEMBLE
HYDROLOGIC FORECASTS AND RIVER GUIDANCE FROM THE SOUTHEAST RIVER
FORECAST CENTER.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...DENSE FOG ADVISORY UNTIL 11 PM EST THIS EVENING FOR GAZ087-088-
099-100-117>119.
SC...NONE.
MARINE...DENSE FOG ADVISORY UNTIL 1 AM EST SATURDAY FOR AMZ352-354.
SMALL CRAFT ADVISORY UNTIL 5 PM EST SATURDAY FOR AMZ374.
&&
$$
ST/BDC
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
816 PM EST FRI FEB 22 2013
...DENSE FOG AFFECTING SOME AREAS TONIGHT...
.SYNOPSIS...
A WARM FRONT IS EXPECTED TO LIFT NORTHWARD INTO SOUTHEAST GEORGIA
THROUGH TONIGHT AS A WEDGE OF HIGH PRESSURE ANCHORS OVER THE
CAROLINAS. A WAVE OF LOW PRESSURE WILL DEVELOP ALONG THE FRONT ON
SATURDAY THEN PUSH NORTHEAST. HIGH PRESSURE WILL BRIEFLY RETURN TO
THE AREA ON SUNDAY BEFORE A WARM FRONT LIFTS NORTH ACROSS THE AREA
LATE MONDAY AND MONDAY NIGHT....FOLLOWED BY THE PASSAGE OF A COLD
FRONT EARLY TUESDAY. DRIER CONDITIONS ARE EXPECTED TO RETURN TO THE
REGION BY THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
AT 22/23Z...THE WEDGE FRONT EXTENDING ROUGHLY ALONG A GEORGETOWN-
WEST ASHLEY-BEAUFORT-SAVANNAH-JESUP LINE. NORTH OF THE FRONT...
TEMPERATURES DROP OFF RAPIDLY INTO THE LOWER 40S TO MID 50S WHILE
FARTHER SOUTH TEMPERATURES WERE IN THE UPPER 50S TO AROUND 70. THE
FRONT WILL MEANDER ALONG THE COAST FOR MUCH OF THE NIGHT BEFORE
BUCKLING NORTH SLIGHTLY AS A WAVE OF LOW PRESSURE DEVELOPS ALONG
IT. THE PRIMARY FORECAST CONCERNS THROUGH SUNRISE CENTER ON
TEMPERATURES AS WELL AS THE POTENTIAL FOR HEAVY RAIN AND DENSE
FOG.
HEAVY RAIN...WATER VAPOR IMAGERY SHOWS A SHORTWAVE OVER FAR
SOUTHEAST ALABAMA AND THE WESTERN FLORIDA PANHANDLE MOVING
NORTHEAST. UPPER FORCING IS SLOWLY INCREASING AHEAD OF THIS
FEATURE AS THE UPPER LEVEL FLOW BECOMES INCREASING MORE DIFLUENT
ACROSS THE SOUTHEAST U.S. IN RESPONSE TO THE DIGGING LONG-WAVE
TROUGH NOTED OVER THE CENTRAL/SOUTHERN PLAINS. CLOUD TOPS ARE
SLOWLY COOLING OVER SOUTHERN GEORGIA AND NORTHERN FLORIDA IN
RESPONSE WITH THE COVERAGE OF RAIN STEADILY EXPANDING/INTENSIFYING
TO THE SOUTHWEST PER KVAX/KTLH RADAR COMPOSITES. RAIN IS EXPECTED
TO OVERSPREAD MUCH OF THE FORECAST AREA OVER THE NEXT SEVERAL
HOURS AS THE SHORTWAVE APPROACHING SOUTHERN GEORGIA DRAWS CLOSER.
PWATS IN EXCESS OF 1.5 INCHES /NEAR THE 99TH PERCENTILE FOR LATE
FEBRUARY/ WILL SUPPORT MODERATE TO OCCASIONALLY HEAVY RAIN AT
TIMES...BUT DO ANTICIPATE ANY WIDESPREAD PROBLEMS WITH FLASH
FLOODING. THE LATEST RUNS OF THE HIGHER RESOLUTION SHORT TERM
MODELS INCLUDING THE RAP AND H3R ARE IN GOOD AGREEMENT IN SHOWING
THE WEDGE FRONT MEANDERING VERY CLOSE TO THE COAST FOR A GOOD
PORTION OF THE NIGHT AND ARE NOW FOCUSING THE AXIS OF HEAVIEST
RAINS OVER SOUTHEAST SOUTH CAROLINA AND SOUTHEAST GEORGIA THROUGH
SUNRISE. WILL ADJUST FIRST PERIOD POPS TO NEAR 100 PERCENT FOR ALL
AREAS...INCREASE QPF SLIGHTLY AND INCLUDE A RAIN HEAVY AT TIMES
QUALIFIER. THE RISK FOR TSTMS AT THIS POINT LOOKS LOW...ALTHOUGH A
RUMBLE OR TWO CAN NOT BE COMPLETELY RULED OUT.
TEMPERATURES...PINNING DOWN TEMPERATURES IS PROVING TO BE NEAR
IMPOSSIBLE. THE LATEST RAP SUGGESTS THE WEDGE FRONT WILL DRIFT
SLIGHTLY EAST OVER THE NEXT FEW HOURS...POSSIBLY EMERGING OFF THE
LOWER SOUTH CAROLINA COAST. WINDS HAVE RECENTLY TURNED NORTH AT
THE CHARLESTON AIRPORT WHICH AGREES WELL WITH THE RAP WIND FIELDS.
HAVE ADJUSTED HOURLY TEMPERATURES TO BETTER MATCH THE REPOSITIONING
OF THE WEDGE FRONT THROUGH SUNRISE. ALSO LOWERED LOW TEMPERATURES
DOWN QUITE A BIT IN SOME AREAS AS SOME LOCALES WELL INLAND WERE
ALREADY BELOW FORECASTED MINIMUMS. COULD VERY WELL SEE A HUGE
SWING IN TEMPERATURES...ESPECIALLY AT THE COAST... SHOULD THE WARM
FRONT PUSHING BACK INLAND QUICKER THAN EXPECTED. LOWS WILL RANGE
FROM THE LOWER 40S WELL INLAND TO AROUND 60 IN THE LUDOWICI-
DARIEN-HINESVILLE CORRIDOR...BUT THIS IS A HIGHLY UNCERTAIN
FORECAST.
DENSE FOG...REPORTS FROM COUNTY WARNING POINTS AND THE SAVANNAH
MEDIA INDICATE DENSE FOG IS BECOMING QUITE WIDESPREAD ACROSS FAR
INTERIOR SOUTHEAST GEORGIA NORTH OF THE WEDGE FRONT. VISIBILITIES
WERE BEING REPORTED TO JUST A FEW FEET IN SOME LOCATIONS. HAVE
HOISTED A DENSE FOG ADVISORY UNTIL 10 PM FOR CANDLER...SCREVEN...
JENKINS AND BULLOCH. EXPECT CONDITIONS TO IMPROVE AS RAIN
INCREASES FROM THE SOUTHWEST. AN ADVISORY HAS ALSO BEEN POSTED FOR
INLAND CHATHAM...COASTAL CHATHAM AND COASTAL BRYAN WHERE SEA FOG
CONTINUES TO PUSH INLAND. SIMILARLY...EXPECT CONDITIONS TO IMPROVE
THERE ONCE RAIN MOVES IN BY 10 PM.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/...
SATURDAY AND SATURDAY NIGHT...A VERY LOW CONFIDENCE FORECAST TO
START THE WEEKEND. A WEDGE FRONT WILL LIKELY BE POSITIONED SOMEWHERE
ACROSS NORTHWEST PORTIONS OF THE FORECAST AREA AT THE START OF THE
DAY AS A WAVE OF LOW PRESSURE DEVELOPS IN THE VICINITY OF CENTRAL
GEORGIA. THE LOW WILL TRACK ALONG THE WEDGE FRONT THROUGH THE DAY
AND SHIFT NORTHEAST OF THE AREA IN THE EVENING AS A TRAILING COLD
FRONT SWINGS THROUGH FROM THE NORTHWEST.
SHOWERS ARE EXPECTED TO BE ONGOING IN THE MORNING ACROSS NORTHWEST
PORTIONS OF THE AREA...WITH THE GREATEST COVERAGE TOWARD THE
MIDLANDS AND EAST-CENTRAL GEORGIA...AS A DISTURBANCE APPROACHES
ALOFT AND ISENTROPIC LIFT STRENGTHENS. SOME SHOWERS SHOULD ALSO BE
STREAMING INTO COASTAL SOUTH CAROLINA FROM THE ADJACENT COASTAL
WATERS. THE BAND OF SHOWERS OVER THE MIDLANDS AND EAST-CENTRAL
GEORGIA SHOULD SHIFT SOUTHEAST OVER THE AREA DURING THE AFTERNOON
AND EARLY EVENING AS THE WAVE OF LOW PRESSURE PASSES...EVENTUALLY
TAPERING OFF OVERNIGHT AS THE TRAILING COLD FRONT PUSHES OFFSHORE.
WITH PRECIPITABLE WATER VALUES AROUND 1.5 INCHES...OR NEARLY 2
STANDARD DEVIATIONS ABOVE NORMAL...THE RAIN COULD BE HEAVY AT TIMES.
THERE IS A POTENTIAL FOR SOME ISOLATED THUNDERSTORMS MAINLY IN THE
AFTERNOON IN THE WARM SECTOR...WHICH SHOULD BE OVER PARTS OF
SOUTHEAST GEORGIA AND COASTAL SOUTHEAST SOUTH CAROLINA.
TEMPERATURES WILL BE VERY DIFFICULT TO FORECAST...WITH A VERY LARGE
GRADIENT EXPECTED OVER THE AREA. WITH THE WEDGE EXPECTED TO PERSIST
ACROSS FAR NORTHWEST PORTIONS OF THE AREA HIGHS THERE ARE ONLY
FORECAST TO BE IN THE LOWER 50S...BUT WITHIN THE WARM SECTOR HIGHS
COULD BE IN THE LOWER TO MID 70S ACROSS NORTH COASTAL GEORGIA AND
AREAS CLOSER TO THE ALTAMAHA. PINNING DOWN THE EXACT POSITION OF THE
WEDGE IS SO DIFFICULT THAT TEMPERATURES IN SOME AREAS COULD BE OFF
BY AS MUCH AS 10 DEGREES FROM THE CURRENT FORECAST.
SUNDAY...HIGH PRESSURE WILL BRIEFLY BUILD OVER THE REGION FROM THE
NORTHWEST WITH RAIN-FREE CONDITIONS EXPECTED. TEMPERATURES COULD
REACH HIGHS AROUND 70 WITH A DOWNSLOPE WIND COMPONENT ALOFT UNDER
MOSTLY SUNNY TO PARTLY CLOUDY SKIES.
SUNDAY NIGHT AND MONDAY...A WARM FRONT EXTENDING FROM A STORM SYSTEM
OVER THE MID-MISSISSIPPI VALLEY WILL SLOWLY LIFT NORTHWARD TOWARD
THE AREA. IT APPEARS THE WARM FRONT COULD ENTER PARTS OF SOUTHEAST
GEORGIA LATE IN THE DAY ON MONDAY. STRENGTHENING ISENTROPIC ASCENT
AND DEEP MOISTURE AHEAD OF THE WARM FRONT SHOULD ALLOW SCATTERED TO
NUMEROUS SHOWERS TO DEVELOP FROM THE SOUTH SUNDAY NIGHT...THEN
BECOME NUMEROUS TO WIDESPREAD ACROSS THE AREA ON MONDAY. SOME
ISOLATED THUNDERSTORMS COULD ALSO DEVELOP ACROSS SOUTHERN AREAS
LATER IN THE DAY DEPENDING ON THE TIMING OF THE FRONT.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
WET CONDITIONS WILL PERSIST OVER THE FORECAST AREA THROUGH EARLY
NEXT WEEK AS A SFC LOW SHIFTS ACROSS THE SOUTHEAST. CONDITIONS WILL
THEN BEGIN TO DRY AS THE SFC LOW SHIFTS OFF THE MID ATLANTIC COAST
AND IS FOLLOWED BY HIGH PRESSURE OVER THE SOUTHEAST. A COOL AND DRY
TREND SHOULD THEN TAKE PLACE THROUGH MUCH OF NEXT WEEK AS A
MID/UPPER LVL LOW BECOMES CUT OFF OVER THE NORTHEASTERN UNITED
STATE. OVERALL...AFTERNOON HIGHS WILL RANGE FROM THE MID 60S ON
TUESDAY TO THE UPPER 50S BY THURSDAY. OVERNIGHT LOWS WILL RANGE FROM
THE UPPER 30S/LOWER 40S ON TUESDAY TO MID 30S/LOWER 40S BY THURSDAY.
&&
.AVIATION /01Z SATURDAY THROUGH WEDNESDAY/...
BOTH TERMINALS WILL BE IFR OR LOWER FOR MOST OF THE NIGHT AS MORE
DEEP MOISTURE CONTINUES ITS TRACK UP THE COAST. DEGRADED
VISIBILITIES DUE TO FOG AND RAIN ARE ALSO A POSSIBILITY AS THE WARM
FRONT AND MINOR SHORTWAVE IMPULSES MOVE UP INTO THE AREA.
CONDITIONS LOOK TO SLIGHTLY IMPROVE BY DAYBREAK AS THE WARM FRONT
LIFTS NORTH OF KSAV AND WIND SPEEDS PICK UP...HOWEVER...MODEL
SOUNDINGS ARE KEEPING THE DEEP MOISTURE IN PLACE FOR THE DAY.
EXTENDED AVIATION OUTLOOK...MVFR OR LOWER CONDITIONS WILL LIKELY
CONTINUE THROUGH SATURDAY NIGHT DUE TO LOW CEILINGS AND REDUCED
VISIBILITIES. VFR CONDITIONS WILL PREVAIL SUNDAY...THEN MVFR OR
LOWER CONDITIONS SHOULD RETURN SUNDAY NIGHT THROUGH MONDAY NIGHT.
VFR CONDITIONS WILL THEN PREVAIL TUESDAY INTO WEDNESDAY.
&&
.MARINE...
SAVANNAH PILOT BOAT REPORTED VSBYS NEAR ZERO IN DENSE SEA FOG AS
FAR OFFSHORE AS BUOY CHARLIE. HILTON HEAD AIRPORT ALSO REPORTING A
CEILING NEAR 100 FT SUGGESTING FOG IS LIKELY NOT TOO FAR OFFSHORE.
HAVE ISSUED A DENSE FOG ADVISORY FOR AMZ352-354 UNTIL 1 AM. ITS
UNCLEAR HOW MUCH VSBYS WILL IMPROVE AS RAIN FILLS IN...SO ONLY
TOOK THE ADVISORY UNTIL 1 AM. ADJUSTMENTS WILL BE NEEDED OVER THE
NEXT FEW HRS. ADJUSTED WINDS OVER THE SOUTH CAROLINA WATERS TO
NORTH OVERNIGHT AS RAP GUIDANCE SUGGESTS THE WEDGE FRONT WILL DROP
SOUTH. ALSO NUDGED THE START TIME FOR THE SMALL CRAFT ADVISORY TO
THE CURRENT TIME OVER THE GEORGIA OFFSHORE WATERS.
SATURDAY THROUGH TUESDAY...SMALL CRAFT ADVISORY CONDITIONS WILL
PERSIST OVER OUTER GEORGIA WATERS THROUGH 5 PM SATURDAY AS A WEDGE
OF HIGH PRESSURE INLAND MAINTAINS AN ENHANCED PRESSURE GRADIENT OVER
THESE WATERS THROUGH MUCH OF THE DAY AND SEAS REMAIN ELEVATED. THE
WEDGE WILL THEN BREAK DOWN LATE AS A SFC LOW TRACKS THROUGH THE
SOUTHEASTERN UNITED STATES AND INTO THE MID ATLANTIC. EXPECT
SOUTHERLY WINDS TO BECOME WEST AS A TRAILING COLD FRONT SHIFTS
THROUGH THE WATERS INTO EARLY SUNDAY. CONDITIONS WILL THEN REMAIN
BELOW SMALL CRAFT ADVISORY LEVELS FOR ALL WATERS THROUGH EARLY
MONDAY AS HIGH PRESSURE DOMINANTS THE PATTERN. WINDS AND SEAS WILL
THEN INCREASE MONDAY AFTERNOON INTO TUESDAY AS A WARM FRONT LIFTS
NORTH AND THEN IS FOLLOWED BY A SFC LOW TRACKING OVER THE WATERS
LATE. WE COULD SEE SMALL CRAFT ADVISORY CONDITIONS AS THE PRESSURE
GRADIENT BECOMES ENHANCED OVER THE WATERS DURING THIS TIME.
&&
.HYDROLOGY...
STORM TOTAL RAINFALL AMOUNTS OF 3-6 INCHES WITH LOCALLY HIGHER
AMOUNTS ARE LIKELY TO OCCUR ACROSS THE REGION THROUGH EARLY NEXT
WEEK BRINGING MORE RELIEF TO DROUGHT STRICKEN AREAS. THESE RAINS
FALLING INTO ALREADY SWOLLEN RIVERS WILL YIELD ADDITIONAL RISES
AND RIVERINE FLOODING THROUGH THE END OF NEXT WEEK. ADDITIONAL
RIVER FLOOD WARNINGS ARE LIKELY PER THE LATEST SHORT TERM ENSEMBLE
HYDROLOGIC FORECASTS AND RIVER GUIDANCE FROM THE SOUTHEAST RIVER
FORECAST CENTER.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...DENSE FOG ADVISORY UNTIL 10 PM EST THIS EVENING FOR GAZ087-088-
099-100-117>119.
SC...NONE.
MARINE...DENSE FOG ADVISORY UNTIL 1 AM EST SATURDAY FOR AMZ352-354.
SMALL CRAFT ADVISORY UNTIL 5 PM EST SATURDAY FOR AMZ374.
&&
$$
ST/BDC
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
723 PM EST FRI FEB 22 2013
...DENSE FOG ADVISORY ISSUED FOR SOME AREAS THROUGH 10 PM...
.SYNOPSIS...
A WARM FRONT IS EXPECTED TO LIFT NORTHWARD INTO SOUTHEAST GEORGIA
THROUGH TONIGHT AS A WEDGE OF HIGH PRESSURE ANCHORS OVER THE
CAROLINAS. A WAVE OF LOW PRESSURE WILL DEVELOP ALONG THE FRONT ON
SATURDAY THEN PUSH NORTHEAST. HIGH PRESSURE WILL BRIEFLY RETURN TO
THE AREA ON SUNDAY BEFORE A WARM FRONT LIFTS NORTH ACROSS THE AREA
LATE MONDAY AND MONDAY NIGHT....FOLLOWED BY THE PASSAGE OF A COLD
FRONT EARLY TUESDAY. DRIER CONDITIONS ARE EXPECTED TO RETURN TO THE
REGION BY THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
AT 22/23Z...THE WEDGE FRONT EXTENDING ROUGHLY ALONG A GEORGETOWN-
WEST ASHLEY-BEAUFORT-SAVANNAH-JESUP LINE. NORTH OF THE FRONT...
TEMPERATURES DROP OFF RAPIDLY INTO THE LOWER 40S TO MID 50S WHILE
FARTHER SOUTH TEMPERATURES WERE IN THE UPPER 50S TO AROUND 70. THE
FRONT WILL MEANDER ALONG THE COAST FOR MUCH OF THE NIGHT BEFORE
BUCKLING NORTH SLIGHTLY AS A WAVE OF LOW PRESSURE DEVELOPS ALONG
IT. THE PRIMARY FORECAST CONCERNS THROUGH SUNRISE CENTER ON
TEMPERATURES AS WELL AS THE POTENTIAL FOR HEAVY RAIN AND DENSE
FOG.
HEAVY RAIN...WATER VAPOR IMAGERY SHOWS A SHORTWAVE OVER FAR
SOUTHEAST ALABAMA AND THE WESTERN FLORIDA PANHANDLE MOVING
NORTHEAST. UPPER FORCING IS SLOWLY INCREASING AHEAD OF THIS
FEATURE AS THE UPPER LEVEL FLOW BECOMES INCREASING MORE DIFLUENT
ACROSS THE SOUTHEAST U.S. IN RESPONSE TO THE DIGGING LONG-WAVE
TROUGH NOTED OVER THE CENTRAL/SOUTHERN PLAINS. CLOUD TOPS ARE
SLOWLY COOLING OVER SOUTHERN GEORGIA AND NORTHERN FLORIDA IN
RESPONSE WITH THE COVERAGE OF RAIN STEADILY EXPANDING/INTENSIFYING
TO THE SOUTHWEST PER KVAX/KTLH RADAR COMPOSITES. RAIN IS EXPECTED
TO OVERSPREAD MUCH OF THE FORECAST AREA OVER THE NEXT SEVERAL
HOURS AS THE SHORTWAVE APPROACHING SOUTHERN GEORGIA DRAWS CLOSER.
PWATS IN EXCESS OF 1.5 INCHES /NEAR THE 99TH PERCENTILE FOR LATE
FEBRUARY/ WILL SUPPORT MODERATE TO OCCASIONALLY HEAVY RAIN AT
TIMES...BUT DO ANTICIPATE ANY WIDESPREAD PROBLEMS WITH FLASH
FLOODING. THE LATEST RUNS OF THE HIGHER RESOLUTION SHORT TERM
MODELS INCLUDING THE RAP AND H3R ARE IN GOOD AGREEMENT IN SHOWING
THE WEDGE FRONT MEANDERING VERY CLOSE TO THE COAST FOR A GOOD
PORTION OF THE NIGHT AND ARE NOW FOCUSING THE AXIS OF HEAVIEST
RAINS OVER SOUTHEAST SOUTH CAROLINA AND SOUTHEAST GEORGIA THROUGH
SUNRISE. WILL ADJUST FIRST PERIOD POPS TO NEAR 100 PERCENT FOR ALL
AREAS...INCREASE QPF SLIGHTLY AND INCLUDE A RAIN HEAVY AT TIMES
QUALIFIER. THE RISK FOR TSTMS AT THIS POINT LOOKS LOW...ALTHOUGH A
RUMBLE OR TWO CAN NOT BE COMPLETELY RULED OUT.
TEMPERATURES...PINNING DOWN TEMPERATURES IS PROVING TO BE NEAR
IMPOSSIBLE. THE LATEST RAP SUGGESTS THE WEDGE FRONT WILL DRIFT
SLIGHTLY EAST OVER THE NEXT FEW HOURS...POSSIBLY EMERGING OFF THE
LOWER SOUTH CAROLINA COAST. WINDS HAVE RECENTLY TURNED NORTH AT
THE CHARLESTON AIRPORT WHICH AGREES WELL WITH THE RAP WIND FIELDS.
HAVE ADJUSTED HOURLY TEMPERATURES TO BETTER MATCH THE REPOSITIONING
OF THE WEDGE FRONT THROUGH SUNRISE. ALSO LOWERED LOW TEMPERATURES
DOWN QUITE A BIT IN SOME AREAS AS SOME LOCALES WELL INLAND WERE
ALREADY BELOW FORECASTED MINIMUMS. COULD VERY WELL SEE A HUGE
SWING IN TEMPERATURES...ESPECIALLY AT THE COAST... SHOULD THE WARM
FRONT PUSHING BACK INLAND QUICKER THAN EXPECTED. LOWS WILL RANGE
FROM THE LOWER 40S WELL INLAND TO AROUND 60 IN THE LUDOWICI-
DARIEN-HINESVILLE CORRIDOR...BUT THIS IS A HIGHLY UNCERTAIN
FORECAST.
DENSE FOG...REPORTS FROM COUNTY WARNING POINTS AND THE SAVANNAH
MEDIA INDICATE DENSE FOG IS BECOMING QUITE WIDESPREAD ACROSS FAR
INTERIOR SOUTHEAST GEORGIA NORTH OF THE WEDGE FRONT. VISIBILITIES
WERE BEING REPORTED TO JUST A FEW FEET IN SOME LOCATIONS. HAVE
HOISTED A DENSE FOG ADVISORY UNTIL 10 PM FOR CANDLER...SCREVEN...
JENKINS AND BULLOCH. EXPECT CONDITIONS TO IMPROVE AS RAIN
INCREASES FROM THE SOUTHWEST. AN ADVISORY HAS ALSO BEEN POSTED FOR
INLAND CHATHAM...COASTAL CHATHAM AND COASTAL BRYAN WHERE SEA FOG
CONTINUES TO PUSH INLAND. SIMILARLY...EXPECT CONDITIONS TO IMPROVE
THERE ONCE RAIN MOVES IN BY 10 PM.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/...
SATURDAY AND SATURDAY NIGHT...A VERY LOW CONFIDENCE FORECAST TO
START THE WEEKEND. A WEDGE FRONT WILL LIKELY BE POSITIONED SOMEWHERE
ACROSS NORTHWEST PORTIONS OF THE FORECAST AREA AT THE START OF THE
DAY AS A WAVE OF LOW PRESSURE DEVELOPS IN THE VICINITY OF CENTRAL
GEORGIA. THE LOW WILL TRACK ALONG THE WEDGE FRONT THROUGH THE DAY
AND SHIFT NORTHEAST OF THE AREA IN THE EVENING AS A TRAILING COLD
FRONT SWINGS THROUGH FROM THE NORTHWEST.
SHOWERS ARE EXPECTED TO BE ONGOING IN THE MORNING ACROSS NORTHWEST
PORTIONS OF THE AREA...WITH THE GREATEST COVERAGE TOWARD THE
MIDLANDS AND EAST-CENTRAL GEORGIA...AS A DISTURBANCE APPROACHES
ALOFT AND ISENTROPIC LIFT STRENGTHENS. SOME SHOWERS SHOULD ALSO BE
STREAMING INTO COASTAL SOUTH CAROLINA FROM THE ADJACENT COASTAL
WATERS. THE BAND OF SHOWERS OVER THE MIDLANDS AND EAST-CENTRAL
GEORGIA SHOULD SHIFT SOUTHEAST OVER THE AREA DURING THE AFTERNOON
AND EARLY EVENING AS THE WAVE OF LOW PRESSURE PASSES...EVENTUALLY
TAPERING OFF OVERNIGHT AS THE TRAILING COLD FRONT PUSHES OFFSHORE.
WITH PRECIPITABLE WATER VALUES AROUND 1.5 INCHES...OR NEARLY 2
STANDARD DEVIATIONS ABOVE NORMAL...THE RAIN COULD BE HEAVY AT TIMES.
THERE IS A POTENTIAL FOR SOME ISOLATED THUNDERSTORMS MAINLY IN THE
AFTERNOON IN THE WARM SECTOR...WHICH SHOULD BE OVER PARTS OF
SOUTHEAST GEORGIA AND COASTAL SOUTHEAST SOUTH CAROLINA.
TEMPERATURES WILL BE VERY DIFFICULT TO FORECAST...WITH A VERY LARGE
GRADIENT EXPECTED OVER THE AREA. WITH THE WEDGE EXPECTED TO PERSIST
ACROSS FAR NORTHWEST PORTIONS OF THE AREA HIGHS THERE ARE ONLY
FORECAST TO BE IN THE LOWER 50S...BUT WITHIN THE WARM SECTOR HIGHS
COULD BE IN THE LOWER TO MID 70S ACROSS NORTH COASTAL GEORGIA AND
AREAS CLOSER TO THE ALTAMAHA. PINNING DOWN THE EXACT POSITION OF THE
WEDGE IS SO DIFFICULT THAT TEMPERATURES IN SOME AREAS COULD BE OFF
BY AS MUCH AS 10 DEGREES FROM THE CURRENT FORECAST.
SUNDAY...HIGH PRESSURE WILL BRIEFLY BUILD OVER THE REGION FROM THE
NORTHWEST WITH RAIN-FREE CONDITIONS EXPECTED. TEMPERATURES COULD
REACH HIGHS AROUND 70 WITH A DOWNSLOPE WIND COMPONENT ALOFT UNDER
MOSTLY SUNNY TO PARTLY CLOUDY SKIES.
SUNDAY NIGHT AND MONDAY...A WARM FRONT EXTENDING FROM A STORM SYSTEM
OVER THE MID-MISSISSIPPI VALLEY WILL SLOWLY LIFT NORTHWARD TOWARD
THE AREA. IT APPEARS THE WARM FRONT COULD ENTER PARTS OF SOUTHEAST
GEORGIA LATE IN THE DAY ON MONDAY. STRENGTHENING ISENTROPIC ASCENT
AND DEEP MOISTURE AHEAD OF THE WARM FRONT SHOULD ALLOW SCATTERED TO
NUMEROUS SHOWERS TO DEVELOP FROM THE SOUTH SUNDAY NIGHT...THEN
BECOME NUMEROUS TO WIDESPREAD ACROSS THE AREA ON MONDAY. SOME
ISOLATED THUNDERSTORMS COULD ALSO DEVELOP ACROSS SOUTHERN AREAS
LATER IN THE DAY DEPENDING ON THE TIMING OF THE FRONT.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
WET CONDITIONS WILL PERSIST OVER THE FORECAST AREA THROUGH EARLY
NEXT WEEK AS A SFC LOW SHIFTS ACROSS THE SOUTHEAST. CONDITIONS WILL
THEN BEGIN TO DRY AS THE SFC LOW SHIFTS OFF THE MID ATLANTIC COAST
AND IS FOLLOWED BY HIGH PRESSURE OVER THE SOUTHEAST. A COOL AND DRY
TREND SHOULD THEN TAKE PLACE THROUGH MUCH OF NEXT WEEK AS A
MID/UPPER LVL LOW BECOMES CUT OFF OVER THE NORTHEASTERN UNITED
STATE. OVERALL...AFTERNOON HIGHS WILL RANGE FROM THE MID 60S ON
TUESDAY TO THE UPPER 50S BY THURSDAY. OVERNIGHT LOWS WILL RANGE FROM
THE UPPER 30S/LOWER 40S ON TUESDAY TO MID 30S/LOWER 40S BY THURSDAY.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
BOTH TERMINALS WILL BE IFR OR LOWER FOR MOST OF THE NIGHT AS MORE
DEEP MOISTURE CONTINUES ITS TRACK UP THE COAST. DEGRADED
VISIBILITIES DUE TO FOG AND RAIN ARE ALSO A POSSIBILITY AS THE WARM
FRONT AND MINOR SHORTWAVE IMPULSES MOVE UP INTO THE AREA.
CONDITIONS LOOK TO SLIGHTLY IMPROVE BY DAYBREAK AS THE WARM FRONT
LIFTS NORTH OF KSAV AND WIND SPEEDS PICK UP...HOWEVER...MODEL
SOUNDINGS ARE KEEPING THE DEEP MOISTURE IN PLACE FOR THE DAY.
EXTENDED AVIATION OUTLOOK...MVFR OR LOWER CONDITIONS WILL LIKELY
CONTINUE THROUGH SATURDAY NIGHT DUE TO LOW CEILINGS AND REDUCED
VISIBILITIES. VFR CONDITIONS WILL PREVAIL SUNDAY...THEN MVFR OR
LOWER CONDITIONS SHOULD RETURN SUNDAY NIGHT THROUGH MONDAY NIGHT.
VFR CONDITIONS WILL THEN PREVAIL TUESDAY INTO WEDNESDAY.
&&
.MARINE...
WATCHING FOR A POSSIBLE MARINE DENSE FOG ADVISORY FOR AT LEAST THE
GEORGIA NEARSHORE WATERS. REPORTS OUT OF TYBEE ISLAND INDICATE THE
SEA FOG IS GETTING PRETTY BAD OVER THE SAVANNAH RIVER ENTRANCE.
ISSUED A MARINE WEATHER STATEMENT TO ADDRESS THIS SITUATION.
ADJUSTED WINDS OVER THE SOUTH CAROLINA WATERS TO NORTH OVERNIGHT
AS RAP GUIDANCE SUGGESTS THE WEDGE FRONT WILL DROP SOUTH. ALSO
NUDGED THE START TIME FOR THE SMALL CRAFT ADVISORY TO THE CURRENT
TIME OVER THE GEORGIA OFFSHORE WATERS.
SATURDAY THROUGH TUESDAY...SMALL CRAFT ADVISORY CONDITIONS WILL
PERSIST OVER OUTER GEORGIA WATERS THROUGH 5 PM SATURDAY AS A WEDGE
OF HIGH PRESSURE INLAND MAINTAINS AN ENHANCED PRESSURE GRADIENT OVER
THESE WATERS THROUGH MUCH OF THE DAY AND SEAS REMAIN ELEVATED. THE
WEDGE WILL THEN BREAK DOWN LATE AS A SFC LOW TRACKS THROUGH THE
SOUTHEASTERN UNITED STATES AND INTO THE MID ATLANTIC. EXPECT
SOUTHERLY WINDS TO BECOME WEST AS A TRAILING COLD FRONT SHIFTS
THROUGH THE WATERS INTO EARLY SUNDAY. CONDITIONS WILL THEN REMAIN
BELOW SMALL CRAFT ADVISORY LEVELS FOR ALL WATERS THROUGH EARLY
MONDAY AS HIGH PRESSURE DOMINANTS THE PATTERN. WINDS AND SEAS WILL
THEN INCREASE MONDAY AFTERNOON INTO TUESDAY AS A WARM FRONT LIFTS
NORTH AND THEN IS FOLLOWED BY A SFC LOW TRACKING OVER THE WATERS
LATE. WE COULD SEE SMALL CRAFT ADVISORY CONDITIONS AS THE PRESSURE
GRADIENT BECOMES ENHANCED OVER THE WATERS DURING THIS TIME.
&&
.HYDROLOGY...
STORM TOTAL RAINFALL AMOUNTS OF 3-6 INCHES WITH LOCALLY HIGHER
AMOUNTS ARE LIKELY TO OCCUR ACROSS THE REGION THROUGH EARLY NEXT
WEEK BRINGING MORE RELIEF TO DROUGHT STRICKEN AREAS. THESE RAINS
FALLING INTO ALREADY SWOLLEN RIVERS WILL YIELD ADDITIONAL RISES
AND RIVERINE FLOODING THROUGH THE END OF NEXT WEEK. ADDITIONAL
RIVER FLOOD WARNINGS ARE LIKELY PER THE LATEST SHORT TERM ENSEMBLE
HYDROLOGIC FORECASTS AND RIVER GUIDANCE FROM THE SOUTHEAST RIVER
FORECAST CENTER.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...DENSE FOG ADVISORY UNTIL 10 PM EST THIS EVENING FOR GAZ087-088-
099-100-117>119.
SC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 5 PM EST SATURDAY FOR AMZ374.
&&
$$
ST/BDC
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
651 PM EST FRI FEB 22 2013
.SYNOPSIS...
A WARM FRONT IS EXPECTED TO LIFT NORTHWARD INTO SOUTHEAST GEORGIA
THROUGH TONIGHT AS A WEDGE OF HIGH PRESSURE ANCHORS OVER THE
CAROLINAS. A WAVE OF LOW PRESSURE WILL DEVELOP ALONG THE FRONT ON
SATURDAY THEN PUSH NORTHEAST. HIGH PRESSURE WILL BRIEFLY RETURN TO
THE AREA ON SUNDAY BEFORE A WARM FRONT LIFTS NORTH ACROSS THE AREA
LATE MONDAY AND MONDAY NIGHT....FOLLOWED BY THE PASSAGE OF A COLD
FRONT EARLY TUESDAY. DRIER CONDITIONS ARE EXPECTED TO RETURN TO THE
REGION BY THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
AT 22/23Z...THE WEDGE FRONT EXTENDING ROUGHLY ALONG A GEORGETOWN-
WEST ASHLEY-BEAUFORT-SAVANNAH-JESUP LINE. NORTH OF THE FRONT...
TEMPERATURES DROP OFF RAPIDLY INTO THE LOWER 40S TO MID 50S WHILE
FARTHER SOUTH TEMPERATURES WERE IN THE UPPER 50S TO AROUND 70. THE
FRONT WILL MEANDER ALONG THE COAST FOR MUCH OF THE NIGHT BEFORE
BUCKLING NORTH SLIGHTLY AS A WAVE OF LOW PRESSURE DEVELOPS ALONG
IT. THE PRIMARY FORECAST CONCERNS THROUGH SUNRISE CENTER ON
TEMPERATURES AS WELL AS THE POTENTIAL FOR HEAVY RAIN AND DENSE
FOG.
HEAVY RAIN...WATER VAPOR IMAGERY SHOWS A SHORTWAVE OVER FAR
SOUTHEAST ALABAMA AND THE WESTERN FLORIDA PANHANDLE MOVING
NORTHEAST. UPPER FORCING IS SLOWLY INCREASING AHEAD OF THIS
FEATURE AS THE UPPER LEVEL FLOW BECOMES INCREASING MORE DIFLUENT
ACROSS THE SOUTHEAST U.S. IN RESPONSE TO THE DIGGING LONG-WAVE
TROUGH NOTED OVER THE CENTRAL/SOUTHERN PLAINS. CLOUD TOPS ARE
SLOWLY COOLING OVER SOUTHERN GEORGIA AND NORTHERN FLORIDA IN
RESPONSE WITH THE COVERAGE OF RAIN STEADILY EXPANDING/INTENSIFYING
TO THE SOUTHWEST PER KVAX/KTLH RADAR COMPOSITES. RAIN IS EXPECTED
TO OVERSPREAD MUCH OF THE FORECAST AREA OVER THE NEXT SEVERAL
HOURS AS THE SHORTWAVE APPROACHING SOUTHERN GEORGIA DRAWS CLOSER.
PWATS IN EXCESS OF 1.5 INCHES /NEAR THE 99TH PERCENTILE FOR LATE
FEBRUARY/ WILL SUPPORT MODERATE TO OCCASIONALLY HEAVY RAIN AT
TIMES...BUT DO ANTICIPATE ANY WIDESPREAD PROBLEMS WITH FLASH
FLOODING. THE LATEST RUNS OF THE HIGHER RESOLUTION SHORT TERM
MODELS INCLUDING THE RAP AND H3R ARE IN GOOD AGREEMENT IN SHOWING
THE WEDGE FRONT MEANDERING VERY CLOSE TO THE COAST FOR A GOOD
PORTION OF THE NIGHT AND ARE NOW FOCUSING THE AXIS OF HEAVIEST
RAINS OVER SOUTHEAST SOUTH CAROLINA AND SOUTHEAST GEORGIA THROUGH
SUNRISE. WILL ADJUST FIRST PERIOD POPS TO NEAR 100 PERCENT FOR ALL
AREAS...INCREASE QPF SLIGHTLY AND INCLUDE A RAIN HEAVY AT TIMES
QUALIFIER. THE RISK FOR TSTMS AT THIS POINT LOOKS LOW...ALTHOUGH A
RUMBLE OR TWO CAN NOT BE COMPLETELY RULED OUT.
TEMPERATURES...PINNING DOWN TEMPERATURES IS PROVING TO BE NEAR
IMPOSSIBLE. THE LATEST RAP SUGGESTS THE WEDGE FRONT WILL DRIFT
SLIGHTLY EAST OVER THE NEXT FEW HOURS...POSSIBLY EMERGING OFF THE
LOWER SOUTH CAROLINA COAST. WINDS HAVE RECENTLY TURNED NORTH AT
THE CHARLESTON AIRPORT WHICH AGREES WELL WITH THE RAP WIND FIELDS.
HAVE ADJUSTED HOURLY TEMPERATURES TO BETTER MATCH THE REPOSITIONING
OF THE WEDGE FRONT THROUGH SUNRISE. ALSO LOWERED LOW TEMPERATURES
DOWN QUITE A BIT IN SOME AREAS AS SOME LOCALES WELL INLAND WERE
ALREADY BELOW FORECASTED MINIMUMS. COULD VERY WELL SEE A HUGE
SWING IN TEMPERATURES...ESPECIALLY AT THE COAST... SHOULD THE WARM
FRONT PUSHING BACK INLAND QUICKER THAN EXPECTED. LOWS WILL RANGE
FROM THE LOWER 40S WELL INLAND TO AROUND 60 IN THE LUDOWICI-
DARIEN-HINESVILLE CORRIDOR...BUT THIS IS A HIGHLY UNCERTAIN
FORECAST.
FOG...SURFACE OBSERVATIONS AND MEDIA REPORTS SUGGEST THE FOG IS
BECOMING RATHER DENSE NORTH OF THE WARM FRONT...ESPECIALLY IN
INTERIOR SOUTHEAST GEORGIA. WILL HOLD OFF ON A DENSE FOG ADVISORY
FOR THIS AREA AS SOME IMPROVEMENT IS EXPECTED TO OCCUR AS RAIN
FILLS IN OVER THE NEXT 1-2 HOURS. HOWEVER...THIS WILL BE WATCHED
CAREFULLY. ALSO...DENSE SEA FOG IS BEGINNING TO PUSH INLAND ALONG
PORTIONS OF NORTH COASTAL GEORGIA WHERE DEWPOINTS ARE SURGING TO
AS MUCH AS 10 DEGREES ABOVE THE CHILLY SHELF WATERS. AGAIN...WILL
HOLD OFF ON HOISTING AN ADVISORY FOR NOW...BUT THIS MAY NEED TO BE
REEVALUATED WITHIN THE HOUR IF CONDITIONS DO NOT IMPROVE. SPECIAL
WEATHER STATEMENTS HAVE BEEN ISSUE TO ADDRESS BOTH AREAS.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/...
SATURDAY AND SATURDAY NIGHT...A VERY LOW CONFIDENCE FORECAST TO
START THE WEEKEND. A WEDGE FRONT WILL LIKELY BE POSITIONED SOMEWHERE
ACROSS NORTHWEST PORTIONS OF THE FORECAST AREA AT THE START OF THE
DAY AS A WAVE OF LOW PRESSURE DEVELOPS IN THE VICINITY OF CENTRAL
GEORGIA. THE LOW WILL TRACK ALONG THE WEDGE FRONT THROUGH THE DAY
AND SHIFT NORTHEAST OF THE AREA IN THE EVENING AS A TRAILING COLD
FRONT SWINGS THROUGH FROM THE NORTHWEST.
SHOWERS ARE EXPECTED TO BE ONGOING IN THE MORNING ACROSS NORTHWEST
PORTIONS OF THE AREA...WITH THE GREATEST COVERAGE TOWARD THE
MIDLANDS AND EAST-CENTRAL GEORGIA...AS A DISTURBANCE APPROACHES
ALOFT AND ISENTROPIC LIFT STRENGTHENS. SOME SHOWERS SHOULD ALSO BE
STREAMING INTO COASTAL SOUTH CAROLINA FROM THE ADJACENT COASTAL
WATERS. THE BAND OF SHOWERS OVER THE MIDLANDS AND EAST-CENTRAL
GEORGIA SHOULD SHIFT SOUTHEAST OVER THE AREA DURING THE AFTERNOON
AND EARLY EVENING AS THE WAVE OF LOW PRESSURE PASSES...EVENTUALLY
TAPERING OFF OVERNIGHT AS THE TRAILING COLD FRONT PUSHES OFFSHORE.
WITH PRECIPITABLE WATER VALUES AROUND 1.5 INCHES...OR NEARLY 2
STANDARD DEVIATIONS ABOVE NORMAL...THE RAIN COULD BE HEAVY AT TIMES.
THERE IS A POTENTIAL FOR SOME ISOLATED THUNDERSTORMS MAINLY IN THE
AFTERNOON IN THE WARM SECTOR...WHICH SHOULD BE OVER PARTS OF
SOUTHEAST GEORGIA AND COASTAL SOUTHEAST SOUTH CAROLINA.
TEMPERATURES WILL BE VERY DIFFICULT TO FORECAST...WITH A VERY LARGE
GRADIENT EXPECTED OVER THE AREA. WITH THE WEDGE EXPECTED TO PERSIST
ACROSS FAR NORTHWEST PORTIONS OF THE AREA HIGHS THERE ARE ONLY
FORECAST TO BE IN THE LOWER 50S...BUT WITHIN THE WARM SECTOR HIGHS
COULD BE IN THE LOWER TO MID 70S ACROSS NORTH COASTAL GEORGIA AND
AREAS CLOSER TO THE ALTAMAHA. PINNING DOWN THE EXACT POSITION OF THE
WEDGE IS SO DIFFICULT THAT TEMPERATURES IN SOME AREAS COULD BE OFF
BY AS MUCH AS 10 DEGREES FROM THE CURRENT FORECAST.
SUNDAY...HIGH PRESSURE WILL BRIEFLY BUILD OVER THE REGION FROM THE
NORTHWEST WITH RAIN-FREE CONDITIONS EXPECTED. TEMPERATURES COULD
REACH HIGHS AROUND 70 WITH A DOWNSLOPE WIND COMPONENT ALOFT UNDER
MOSTLY SUNNY TO PARTLY CLOUDY SKIES.
SUNDAY NIGHT AND MONDAY...A WARM FRONT EXTENDING FROM A STORM SYSTEM
OVER THE MID-MISSISSIPPI VALLEY WILL SLOWLY LIFT NORTHWARD TOWARD
THE AREA. IT APPEARS THE WARM FRONT COULD ENTER PARTS OF SOUTHEAST
GEORGIA LATE IN THE DAY ON MONDAY. STRENGTHENING ISENTROPIC ASCENT
AND DEEP MOISTURE AHEAD OF THE WARM FRONT SHOULD ALLOW SCATTERED TO
NUMEROUS SHOWERS TO DEVELOP FROM THE SOUTH SUNDAY NIGHT...THEN
BECOME NUMEROUS TO WIDESPREAD ACROSS THE AREA ON MONDAY. SOME
ISOLATED THUNDERSTORMS COULD ALSO DEVELOP ACROSS SOUTHERN AREAS
LATER IN THE DAY DEPENDING ON THE TIMING OF THE FRONT.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
WET CONDITIONS WILL PERSIST OVER THE FORECAST AREA THROUGH EARLY
NEXT WEEK AS A SFC LOW SHIFTS ACROSS THE SOUTHEAST. CONDITIONS WILL
THEN BEGIN TO DRY AS THE SFC LOW SHIFTS OFF THE MID ATLANTIC COAST
AND IS FOLLOWED BY HIGH PRESSURE OVER THE SOUTHEAST. A COOL AND DRY
TREND SHOULD THEN TAKE PLACE THROUGH MUCH OF NEXT WEEK AS A
MID/UPPER LVL LOW BECOMES CUT OFF OVER THE NORTHEASTERN UNITED
STATE. OVERALL...AFTERNOON HIGHS WILL RANGE FROM THE MID 60S ON
TUESDAY TO THE UPPER 50S BY THURSDAY. OVERNIGHT LOWS WILL RANGE FROM
THE UPPER 30S/LOWER 40S ON TUESDAY TO MID 30S/LOWER 40S BY THURSDAY.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
BOTH TERMINALS WILL BE IFR OR LOWER FOR MOST OF THE NIGHT AS MORE
DEEP MOISTURE CONTINUES ITS TRACK UP THE COAST. DEGRADED
VISIBILITIES DUE TO FOG AND RAIN ARE ALSO A POSSIBILITY AS THE WARM
FRONT AND MINOR SHORTWAVE IMPULSES MOVE UP INTO THE AREA.
CONDITIONS LOOK TO SLIGHTLY IMPROVE BY DAYBREAK AS THE WARM FRONT
LIFTS NORTH OF KSAV AND WIND SPEEDS PICK UP...HOWEVER...MODEL
SOUNDINGS ARE KEEPING THE DEEP MOISTURE IN PLACE FOR THE DAY.
EXTENDED AVIATION OUTLOOK...MVFR OR LOWER CONDITIONS WILL LIKELY
CONTINUE THROUGH SATURDAY NIGHT DUE TO LOW CEILINGS AND REDUCED
VISIBILITIES. VFR CONDITIONS WILL PREVAIL SUNDAY...THEN MVFR OR
LOWER CONDITIONS SHOULD RETURN SUNDAY NIGHT THROUGH MONDAY NIGHT.
VFR CONDITIONS WILL THEN PREVAIL TUESDAY INTO WEDNESDAY.
&&
.MARINE...
WATCHING FOR A POSSIBLE MARINE DENSE FOG ADVISORY FOR AT LEAST THE
GEORGIA NEARSHORE WATERS. REPORTS OUT OF TYBEE ISLAND INDICATE THE
SEA FOG IS GETTING PRETTY BAD OVER THE SAVANNAH RIVER ENTRANCE.
ISSUED A MARINE WEATHER STATEMENT TO ADDRESS THIS SITUATION.
ADJUSTED WINDS OVER THE SOUTH CAROLINA WATERS TO NORTH OVERNIGHT
AS RAP GUIDANCE SUGGESTS THE WEDGE FRONT WILL DROP SOUTH. ALSO
NUDGED THE START TIME FOR THE SMALL CRAFT ADVISORY TO THE CURRENT
TIME OVER THE GEORGIA OFFSHORE WATERS.
SATURDAY THROUGH TUESDAY...SMALL CRAFT ADVISORY CONDITIONS WILL
PERSIST OVER OUTER GEORGIA WATERS THROUGH 5 PM SATURDAY AS A WEDGE
OF HIGH PRESSURE INLAND MAINTAINS AN ENHANCED PRESSURE GRADIENT OVER
THESE WATERS THROUGH MUCH OF THE DAY AND SEAS REMAIN ELEVATED. THE
WEDGE WILL THEN BREAK DOWN LATE AS A SFC LOW TRACKS THROUGH THE
SOUTHEASTERN UNITED STATES AND INTO THE MID ATLANTIC. EXPECT
SOUTHERLY WINDS TO BECOME WEST AS A TRAILING COLD FRONT SHIFTS
THROUGH THE WATERS INTO EARLY SUNDAY. CONDITIONS WILL THEN REMAIN
BELOW SMALL CRAFT ADVISORY LEVELS FOR ALL WATERS THROUGH EARLY
MONDAY AS HIGH PRESSURE DOMINANTS THE PATTERN. WINDS AND SEAS WILL
THEN INCREASE MONDAY AFTERNOON INTO TUESDAY AS A WARM FRONT LIFTS
NORTH AND THEN IS FOLLOWED BY A SFC LOW TRACKING OVER THE WATERS
LATE. WE COULD SEE SMALL CRAFT ADVISORY CONDITIONS AS THE PRESSURE
GRADIENT BECOMES ENHANCED OVER THE WATERS DURING THIS TIME.
&&
.HYDROLOGY...
STORM TOTAL RAINFALL AMOUNTS OF 3-6 INCHES WITH LOCALLY HIGHER
AMOUNTS ARE LIKELY TO OCCUR ACROSS THE REGION THROUGH EARLY NEXT
WEEK BRINGING MORE RELIEF TO DROUGHT STRICKEN AREAS. THESE RAINS
FALLING INTO ALREADY SWOLLEN RIVERS WILL YIELD ADDITIONAL RISES
AND RIVERINE FLOODING THROUGH THE END OF NEXT WEEK. ADDITIONAL
RIVER FLOOD WARNINGS ARE LIKELY PER THE LATEST SHORT TERM ENSEMBLE
HYDROLOGIC FORECASTS AND RIVER GUIDANCE FROM THE SOUTHEAST RIVER
FORECAST CENTER.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 5 PM EST SATURDAY FOR AMZ374.
&&
$$
ST/BDC
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
610 PM CST FRI FEB 22 2013
.SYNOPSIS...
ISSUED AT 257 PM CST FRI FEB 22 2013
SLOWLY FILLING SURFACE LOW THAT HAS MOVED NORTH ACROSS THE FORECAST
AREA TODAY IS CONTINUING TO MOVE UP INTO SOUTHERN WISCONSIN...AND AS
OF 2 PM WAS LOCATED WEST OF MADISON WISCONSIN...WITH A BROAD AREA OF
PRESSURE FALLS OVER WISCONSIN. A VERY WEAK TROUGH AXIS EXTENDS BACK
INTO NORTHERN IOWA...WHERE SNOW CONTINUES TO FALL VERY LIGHTLY. LOW
CLOUDS EXTEND BACK INTO NORTHERN MISSOURI. THERE IS AN AREA IN
NORTHWEST MISSOURI WHERE THE CLOUDS HAVE EITHER THINNED OR CLEARED
OUT ENTIRELY AS WE CAN SEE THE TEXTURE OF THE GROUND BENEATH ON
VISIBLE SATELLITE IMAGERY. THIS IS IN A OBSERVATIONAL DATA VOID
AREA...SO IT IS HARD TO DETERMINE WHAT EXACTLY IS GOING ON. AT
UPPER LEVELS...BROAD UPPER LEVEL TROUGH OVER THE WESTERN CONUS WITH
THE STRONG SHORTWAVE OVER THE MIDWEST ASSOCIATED WITH THIS STORM
SYSTEM. STRONG PRESSURE FALLS AHEAD OF THE SHORTWAVE IMPLY THAT IT
WILL CONTINUE NORTHEAST...BUT SMALL RISES BEHIND IT SHOW THAT IT IS
FILLING AND THE BROADER SCALE TROUGH IS STILL DEEPENING. ..LE..
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 257 PM CST FRI FEB 22 2013
THIS AFTERNOON THE SNOW BAND IS EXPECTED TO CONTINUE TO MOVE
NORTHEAST OUT OF THE AREA...AND PLAN ON ALLOWING THE WINTER STORM
WARNING AND ADVISORY EXPIRE HERE AT 3 PM. SOME FLURRIES WILL LIKELY
STILL AFFECT THE NORTHERN THIRD OF THE FORECAST AREA WITH SOME LOW
LEVEL CONVERGENCE AND LIFT GOING ON ACCORDING TO THE RUC THIS
EVENING. THUS...HAVE CONTINUED THE SLIGHT CHANCE POPS THIS EVENING
BUT WITH NO ACCUMULATIONS EXPECTED.
TONIGHT THE SURFACE LOW EJECTS OFF TO THE NORTHEAST...AND WILL BE
OVER THE UP OF MICHIGAN BY 06Z TONIGHT. THAT WILL DRAW THE LIFT AND
MOST OF THE MOISTURE OFF TO THE NORTHEAST...LEAVING US WITH SOME
LINGERING LOW LEVEL MOISTURE. IN FACT...ACCORDING TO SOUNDINGS WE
REMAIN FAIRLY WELL SATURATED BELOW 850MB THROUGH SATURDAY MORNING.
FLURRIES SHOULD BE POSSIBLE AS THE LEAST LITTLE WIGGLE IS GOING TO
PRODUCE THEM. IT APPEARS THAT WE WILL BE COLD ENOUGH AT THE TOP OF
THAT LAYER FOR THESE TO BE FLURRIES INSTEAD OF FREEZING DRIZZLE..BUT
LATER SHIFTS WILL HAVE TO WATCH FOR THIS. UPSTREAM MIN TEMPERATURES
FELL INTO THE TEENS OVER NEBRASKA AND KANSAS LAST NIGHT...SO HAVE
KEPT THE MIN TEMPS IN THE TEENS OVERNIGHT. MAY BE SLIGHTLY WARMER
WITH THE EXTRA CLOUD COVER...SO DID NOT BRING IN ANY SINGLE DIGIT
VALUES. THE EXTRA CLOUD COVER IS ALSO GOING TO KEEP TEMPS FROM
FALLING OFF VERY FAST OVERNIGHT...SO A SLOW DROP OFF IN THE EVENING
IS EXPECTED.
SATURDAY TO BE COLD AND QUIET WITH THE STORM OFF TO THE NORTHEAST
AND A GRADUAL CLEARING TREND FROM THE SOUTH. WE ARE NOT BRINGING IN
A COLD AIRMASS BEHIND THIS SYSTEM...BUT WITH THE SNOW COVER WE ARE
GOING TO BE COLDER THAN WE WOULD WITHOUT. SO...EXPECT HIGHS IN THE
20S TO NEAR 30. LINGERING LOW LEVEL MOISTURE SHOULD LIFT TO
AFTERNOON STRATOCUMULUS...BUT STILL ALLOWING A FAIR AMOUNT OF
SUNSHINE THROUGH. ..LE..
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 257 PM CST FRI FEB 22 2013
ANOTHER MAJOR AND STRONGER WINTER STORM FOR MONDAY/TUESDAY THE MAIN
FORECAST CHALLENGE.
OVERVIEW...INITIALIZATION GOOD TO EXCELLENT UPSTREAM INTO THE NORTH
PACIFIC. THE 18Z VERIFICATION SUPPORT ALL 4 LONGER RANGE SOLUTIONS
VERIFYING WELL AND ARE ALL SIMILAR. THATS THE GOOD NEWS...UNLESS ONE
LIKES LOTS OF SNOW...THEY ALL PUT AREA IN THE WHEELHOUSE OF A MAJOR
WINTER STORM WITH STRONG WINDS. PREFER A BLEND OF ALL 4 AS A MIX
WHICH SUPPORTS MOST OR ALL THE AREA TO PICK UP ANOTHER 4-6+ INCHES OF
SNOW WITH LOCALLY UP TO OVER 12 INCHES POSSIBLE WITH WINDS OF 20 TO
35+ MPH AND POSSIBLY HIGHER. THE CONSISTENCY OF FORCING OF UPPER JET
STRUCTURE TOOLS ALL SUGGEST IF THIS TREND CONTINUES THE NEXT 24 HOURS
THAT OUR AREA WILL SEE A MAJOR...HIGHER END WINTER STORM EVENT WITH
POSSIBLE NEAR BLIZZARD CONDITIONS. WILL UPDATE THE LOCAL HWODVN
HAZARDOUS WEATHER OUTLOOK PRODUCT FOR STRONGER AND HIGHER IMPACT
WORDING.
SATURDAY NIGHT AND SUNDAY...VERY MINOR CHANGES WITH LESS CLOUDS ARE
LIKELY SUPPORTING LOWER MINS FROM OUR SNOW-PACK AND HIGHER MAX TEMP
VALUES FROM LATE FEBRUARY SUNSHINE. LATER SHIFTS MAY NEED TO BUMP
HIGHS A FEW MORE DEGREES DUE TO THE SUNSHINE. SUNDAY NIGHT...SEE
INCREASING CLOUDS AND KEPT VERY LOW POPS FAR WEST SECTIONS OVERNIGHT
AS LEADING EDGE OF ELEVATED FORCING FOR THE NEXT MAJOR WINTER STORM
ARRIVES WITH MAIN BRUNT OF FORCING ON TAP TO IMPACT THE AREA LATER ON
MONDAY PM HOURS INTO TUESDAY.
MONDAY THROUGH NEXT WEDNESDAY...HAVE UPPED POPS MONDAY NIGHT AND
TUESDAY TO LIKELY WITH MODERATE TO HEAVY SNOW AMOUNTS SUGGESTED.
NUMEROUS TOOLS SUGGEST MOST OF THE AREA TO SEE WELL OVER 4+ INCHES
WITH MOST RELIABLE TOOLS ALL SUGGESTING A SWATH OF 6-12+ INCHES OF
HEAVY SNOW THAT RIGHT NOW IS TRENDING TOWARD A IRK-MUS-FEP LINE.
THIS SHOULD BE BETTER CLARIFIED IN THE NEXT 24 HOURS. IF PHASING
ON THE BACK SIDE OCCURS AS SUGGESTED BY SOME SOLUTIONS WITH STRONGER
OCCLUSION THEN STRONGER COLD CONVEYOR BELT SUGGESTED AND NEAR
BLIZZARD CONDITIONS LIKELY. SOME TOOLS SUGGEST WIND GUSTS OF 40-45
MPH WHICH ARE VERY CLOSE TO BLIZZARD THRESHOLD FOR LATER SHIFTS TO
MONITOR. THERE IS NO DOUBT THIS WILL BE A MAJOR EVENT LAST 12-18+
HOURS AND LIKELY GREATER THAN THE EVENT THE PAST 24 HOURS. THIS IS
A DEVELOPING SYSTEM THAT WILL STRENGTHEN VERSUS A WEAKENING AND
FILLING SYSTEM THAT PASSED. ADD WERE IN THE NATURAL BAROCLINIC
ZONE OF A PRONOUNCED SNOW AND NO SNOW LINE...THIS MAKES RISK OF A
MAJOR EVENT GREATER. THE DATA AS OF NOW...SUPPORTS AT LEAST PART
OF THE AREA WILL SEE A MAJOR WINTER STORM. AREA SNOW TO LIQUID WATER
EQUIVALENT RATIOS ARE SUGGESTED TO BE IN THE 12-15 TO 1 RANGE. ARE
TEMPERATURES SHOULD STAY IN THE MID 20S TO LOWER 30S FOR THIS EVENT.
THURSDAY AND FRIDAY...DRY WITH BELOW NORMAL TEMPERATURES AND WITH
AN EVEN GREATER THICKER AND FRESH SNOW PACK LIKELY...AREA TEMPS ARE
AGAIN PROBABLY TOO MILD. MINS COULD BE AT LEAST 5 TO 10 DEGREES TOO
MILD FOR LATER SHIFTS TO RECONSIDER. NORTHWESTERLY FLOW AND BELOW
NORMAL TEMPERATURES REMAIN APPEAR LIKELY INTO THE FIRST FEW DAYS OF
MARCH...ALL INDICATIONS ARE THIS MARCH WILL NOTHING LIKE THE
RECORD WARM MARCH OF 2012.
NICHOLS
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 552 PM CST FRI FEB 22 2013
CYCLONIC FLOW AROUND LOW PRESSURE OVER WISCONSIN AND HIGH LOW
LEVEL MOISTURE WILL KEEP CLOUDS BASED BETWEEN 2KFT AND 3KFT IN
PLACE THROUGH SATURDAY MORNING. CLEARING SHOULD OCCUR FROM LATE
SATURDAY MORNING INTO THE AFTERNOON AS DRIER AIR MOVES IN FROM THE
WEST. A FEW SNOW SHOWERS WILL LINGER OVER AREAS NORTH OF I80 EARLY
THIS EVENING WITH VISIBLITIES AS LOW AS 1 OR 2 MILES IN THE
HEAVIER SHOWERS. AFTER THE SNOW SHOWERS END VSBYS SHOULD BE AOA
6SM THROUGH SATURDAY AFTERNOON.
DLF
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...LE
SHORT TERM...LE
LONG TERM...WDN
AVIATION...DLF
AREA FORECAST DISCUSSION
NWS DES MOINES IA
358 PM CST THU FEB 21 2013
.SHORT TERM /TONIGHT/...
SNOW BAND ADVECTING NORTHWARD ACROSS MUCH OF THE FORECAST AREA THIS
AFTERNOON INTO THE EVENING CAUSING RAPIDLY DETERIORATING CONDITIONS.
MODELS REMAIN IN GREAT AGREEMENT WITH TIMING AND PLACEMENT OF
HEAVIEST BAND TONIGHT AND WITH THE UPPER LOW TRACK DURING THE
OVERNIGHT HOURS. LEANED TOWARD THE TIMING OF NAM12/HRRR/HIRES
ARW-WRF FOR BAND DURING THE EVENING HOURS AND SREF/NAM OVERNIGHT.
IMPRESSIVE ISENTROPIC LIFT AHEAD OF THE UPPER LOW...GENERALLY ALONG
THE 285K TO 305K ISENTROPIC SURFACES...COMBINED WITH GOOD MOISTURE
TRANSPORT WILL CONTINUE TO PUSH THE CURRENT SNOW BAND FURTHER NORTH
LATE THIS AFTERNOON AND EVENING. THE ISENTROPIC LIFT DIMINISHES IN
STRENGTH AS THE UPPER LOW APPROACHES FROM KANSAS LATER TONIGHT INTO
THE OVERNIGHT HOURS BUT ENOUGH DEEP FORCING ASSOCIATED WITH IT AS IT
PASSES THROUGH THE STATE TO KEEP HIGH POPS GOING OVERNIGHT.
ALSO...EXPECTING THE SNOW TO CONTINUE TO FILL IN ACROSS SOUTHWEST
IOWA AND REMAIN FAIRLY PERSISTENT ACROSS THE FORECAST AREA FOR
SEVERAL HOURS TONIGHT. RAP CONFIRMS THIS AS IT HAS MAX OMEGA WITHIN
THE DENDRITIC LAYER PERSISTING THROUGH 02Z AT DSM...AND THROUGH 06Z
ACROSS NORTH CENTRAL IOWA. EVEN WITH SNOW INTENSITIES
DIMINISHING...STILL EXPECTING LIGHTER SNOWFALL ACCUMULATIONS B/T 06Z
AND 12Z FRIDAY WITH PASSAGE OF THE UPPER LOW. LEANED TOWARD A BLEND
OF THE GFS/NAM FOR QPF AMOUNTS AND STILL ON TRACK FOR GOOD SWATH OF
6 TO 9 INCHES GENERALLY SOUTH OF HIGHWAY 20. SLIGHTLY LESS FURTHER
NORTH AS THE BEST FORCING SKIRTS TO ITS SOUTHEAST.
SHARP PRESSURE GRADIENT ACROSS THE STATE KEEPS EAST TO NORTHEAST
WINDS GUSTS THROUGH 03-06Z TONIGHT BEFORE DIMINISHING. 925MB WINDS
AT 03Z STILL GUSTING AT 30KTS OVER CENTRAL PORTION OF THE FORECAST
AREA. VISIBILITY RAPIDLY DIMINISHING WITH THE ONSET OF THE SNOW AND
WILL PERSIST BEFORE THE WINDS WEAKEN LATER THIS EVENING.
.LONG TERM /FRIDAY THROUGH THURSDAY/...
UPPER LOW WILL BE DEPARTING TO THE NORTHEAST ON FRIDAY WITH FORCING
SUBSIDING THROUGH THE DAY. HAVE CONTINUED CATEGORICAL WORDING IN
THE FAR NORTHEAST DURING THE MORNING WITH A DECENT GRADIENT TO
ESSENTIALLY NO PCPN IN FAR SOUTHWEST. SUBSIDENCE WILL CONTINUE TO
OVERSPREAD THE AREA DURING THE DAY AND HAVE CUT THE POPS OFF ACROSS
THE SOUTH BY AFTERNOON AND LEFT SCATTERED SNOW SHOWERS AND FLURRIES
IN THE NORTH UNDER THE UPPER LOW WHERE SOME WEAK LIFT WILL CONTINUE
TO RESIDE. THE THREAT OF ANY PCPN WILL END BY SATURDAY NIGHT IN THE
NORTH AS THE SYSTEM PULLS AWAY. THE 850MB THERMAL TROF IS NEARLY
ASSOCIATED WITH THE UPPER LOW SO WARM ADVECTION WILL COMMENCE
IMMEDIATELY ON FRIDAY NIGHT INTO SATURDAY ON BACKSIDE OF THE SYSTEM.
THIS WILL KEEP TEMPERATURES FROM DROPPING AS MUCH AS WOULD BE
EXPECTED WITH FRESH SNOW COVER WITH HIGHS ON SUNDAY APPROACHING OR
SLIGHTLY ABOVE FREEZING.
FOCUS WILL THEN SHIFT ON SHORTWAVE DROPPING INTO THE ROCKIES DURING
THE WEEKEND. GFS IS FARTHER NORTH AND FASTER WITH THE EVOLUTION OF
THIS SYSTEM AND APPEARS TO BE THE ODD MODEL OUT. THE EURO AND GEM
HAVE BEEN MORE CONSISTENT DIGGING THE SYSTEM THROUGH THE
INTERMOUNTAIN WEST THEN MOVING THE STORM EASTWARD THROUGH THE MID
MISSISSIPPI RIVER VALLEY. THE IMPLICATIONS OF THIS WOULD BE TO KEEP
THE BULK OF FORCING AND MOISTURE TO OUR SOUTH WITH MISSOURI SEEING
THE WORST CONDITIONS. HOWEVER...SOME WEAKER FORCING WILL BLEED INTO
THE STATE AS THE UPPER TROF IS ELONGATED FROM THE CENTRAL INTO THE
NORTHERN PLAINS. THEREFORE...SOME SNOWFALL IS STILL EXPECTED ACROSS
THE STATE FROM LATE SUNDAY NIGHT INTO TUESDAY MORNING...PRIMARILY
IMPACTING THE SOUTHERN HALF OF IOWA. SOME LIGHT TO MODERATE
ACCUMULATIONS ARE EXPECTED WITH THIS STORM AND WILL CONTINUE TO
MONITOR THE TRACK SINCE ANY NORTHWARD SHIFT WOULD BEGIN TO BRING
SIGNIFICANTLY HIGHER AMOUNTS INTO THE STATE. AFTER THIS SYSTEM
PULLS AWAY...DRIER CONDITIONS ARE EXPECTED WITH TEMPERATURES BELOW
NORMAL WITH COOL NORTHERLY FLOW BEHIND THE SYSTEM.
&&
.AVIATION...21/18Z
SNOW DEVELOPING OVER SOUTHERN IOWA WILL CONTINUE TO PUSH NORTH AND
AFFECT DSM/OTM OVER THE NEXT 2-3 HOURS. HAVE MVFR CONDITIONS QUICKLY
DIMINISHING TO LIFR CONDITIONS AT DSM/OTM AFTER 21Z AND WILL PERSIST
THROUGH THE EARLY EVENING HOURS. TIMING FOR ALO/MCW/FOD IS LATER
THIS AFTERNOON/EARLY EVENING. CONFIDENCE IS HIGH WITH RAPIDLY
DETERIORATING CONDITIONS. EXPECTING A GOOD 4-6 HOUR PERIOD OF BLSN
AND LIFR VIS BEFORE SNOW BECOMES LIGHTER LATER THIS EVENING. HAVE
IFR/MVFR VIS/CIGS THROUGH FRIDAY MORNING.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL NOON CST FRIDAY FOR
ADAIR-ADAMS-APPANOOSE-AUDUBON-BOONE-CALHOUN-CARROLL-CASS-CLARKE-
CRAWFORD-DALLAS-DAVIS-DECATUR-GREENE-GUTHRIE-JASPER-LUCAS-MADISON-
MAHASKA-MARION-MONROE-POLK-POWESHIEK-RINGGOLD-SAC-STORY-TAYLOR-UNION-
WAPELLO-WARREN-WAYNE-BLACK HAWK-BREMER-BUTLER-CERRO GORDO-EMMET-
FRANKLIN-GRUNDY-HAMILTON-HANCOCK-HARDIN-HUMBOLDT-KOSSUTH-MARSHALL-
PALO ALTO-POCAHONTAS-TAMA-WEBSTER-WINNEBAGO-WORTH-WRIGHT.
&&
$$
AVIATION/SHORT TERM...KLP
LONG TERM...COGIL
AREA FORECAST DISCUSSION
NWS TOPEKA KS
342 PM CST THU FEB 21 2013
.DISCUSSION...
TONIGHT THROUGH FRIDAY...
THE UPPER LEVEL LOW WAS LOCATED ACROSS THE NORTHEAST TEXAS PANHANDLE
THIS AFTERNOON. ONE 1.5PV ANOMALY WAS LIFTING NORTHWARD ACROSS WEST
CENTRAL KS...WITH A SECOND 1.5PV ANOMALY OVER WESTERN OK. THE
SHORT-TERM MODELS...HRRR AND RAP SHOW THE 1.5PV ANOMALY
LIFTING NORTHEAST ACROSS EASTERN KS. AHEAD OF THE 1.5PV ANOMALY THE
FRONTOGENETICAL FORCING SHOULD INCREASE TO PROVIDE A PERIOD OF LIGHT
SNOW. THE MODELS SHOW AN INCREASE IN THE NEGATIVE SATURATED
EPV...CSI...WHICH COULD CAUSE SOME SLIGHTLY HEAVIER SNOW
BANDS...THUS THE WESTERN AND CENTRAL COUNTIES OF THE CWA COULD SEE
SOME LOCALLY HIGHER SNOW AMOUNTS.
UNTIL THE DENDRITIC GROWTH ZONE SATURATES LATER THIS AFTERNOON
THERE MAY BE PERIODS OF FREEZING DRIZZLE ACROSS THE EASTERN HALF OF
THE CWA. THE PATCHY FREEZING DRIZZLE MAY REFORM LATER THIS EVENING
ONCE THE STRONGER ASCENT SHIFTS NORTHEAST OF THE CWA. ISENTROPIC
DOWNGLIDE SHOULD BRING AN END THE THE FREEZING DRIZZLE CHANCE AFTER
MIDNIGHT.
THE STORM TOTAL SNOWFALL WILL RANGE FROM 6 TO 15 INCHES WITH SOME
LOCALLY HIGHER AMOUNTS.
I WILL KEEP THE WINTER STORM WARNING IN EFFECT UNTIL 00Z FOR THE
WESTERN HALF OF THE CWA AND UNTIL MIDNIGHT FOR THE EASTERN HALF OF
THE CWA.
FRIDAY...THE SKIES SHOULD BEGIN TO CLEAR FROM WEST TO EAST ACROSS
THE CWA THROUGH THE MID AND LATE MORNING HOURS. HIGHS WILL CONTINUE
TO BE COLD WITH MID 20S...GIVEN SEVERAL INCHES OF SNOW COVER.
GARGAN
FRIDAY NIGHT THROUGH THURSDAY...
DRY CONDITIONS ARE EXPECTED FOR THE START OF THE WEEKEND AS THE
UPPER LEVEL TROUGH THAT IMPACTED THE REGION WITH WINTER WEATHER
TODAY SLIDES NORTH TOWARD THE GREAT LAKES REGION. SURFACE HIGH
PRESSURE BRIEFLY WILL SETTLE INTO THE REGION BEHIND THE EXITING
STORM SYSTEM BEFORE THE NEXT UPPER LEVEL TROUGH BEGINS TO DIG
SOUTHWARD ACROSS THE NORTHERN AND CENTRAL PLAINS DURING THE LATTER
PART OF THE WEEKEND. THERE IS STILL UNCERTAINTY AMONGST THE MODELS
REGARDING JUST HOW FAR SOUTH THIS TROUGH WILL DIG ALONG AND EAST OF
THE ROCKY MOUNTAINS AND HOW QUICKLY THE UPPER LOW EJECTS
NORTHEASTWARD ACROSS THE FORECAST AREA AND FURTHER EAST OF THE AREA.
THESE MODEL DISCREPANCIES LEAD TO DIFFICULTIES IN PINNING DOWN THE
TIMING OF ANY PRECIPITATION FROM THIS SYSTEM. MODELS SEEM TO BE A
BIT SLOWER IN BRINGING THE SYSTEM INTO THE AREA...SO HAVE DECREASED
POPS FOR SUNDAY WITH CHANCE POPS FOR THE SUNDAY NIGHT THROUGH MONDAY
NIGHT TIMEFRAME. THESE POPS BEST REFLECT A BLEND OF THE ECMWF/GEM.
THE GFS CURRENTLY IS AN OUTLIER IN KEEPING THE UPPER TROUGH FURTHER
NORTH AND ONLY HAVING PRECIPITATION SKIMMING ACROSS THE NORTHERN
PORTION OF THE FORECAST AREA. DEPENDING UPON THE TIMING OF
PRECIPITATION...THE REGION COULD SEE A COMBINATION OF RAIN AND SNOW
SHOWERS WITH THIS SYSTEM. AT THIS TIME...THE SYSTEM LOOKS TO EXIT
EAST OF THE AREA BY TUESDAY. A WEAK RIDGE WILL MOVE INTO THE REGION
BEHIND THIS TROUGH WITH DRY CONDITIONS EXPECTED FOR MID-WEEK. BY THE
END OF THE PERIOD MODEL DISCREPANCIES EXIST WITH REGARDS TO THE NEXT
SHORTWAVE THAT EJECTS INTO THE CENTRAL PLAINS. KEPT ANY MENTION OF
PRECIPITATION OUT OF THE FORECAST AT THIS TIME.
TEMPERATURE FORECASTS FOR THE PERIOD HAVE BEEN COMPLICATED BY THE
SEVERAL INCHES OF SNOW RECEIVED ACROSS THE FORECAST AREA FROM
TODAY`S STORM. WITH THIS IN MIND...HAVE TRENDED WITH TEMPERATURES
STAYING BELOW THE SEASONAL NORMALS THROUGH THE EXTENDED FORECAST
PERIOD...WITH HIGHS GENERALLY IN THE 30S. THE COLDEST NIGHT LOOKS TO
BE FRIDAY NIGHT/EARLY SATURDAY MORNING AS LOW TEMPERATURES PLUMMET
INTO THE SINGLE DIGITS...WITH WIND CHILL VALUES ANYWHERE FROM ZERO
TO 8 BELOW ZERO. OTHERWISE...LOWS GENERALLY LOOK TO BE IN THE TEENS
AND 20S. TEMPERATURE FORECASTS WILL NEED TO BE ADJUSTED DEPENDING
UPON ANY MELTING OF SNOW THAT OCCURS IN THE UPCOMING DAYS.
ACH
&&
.AVIATION...
THE HEAVIER SNOW HAS MOVED NORTH OF THE KTOP AND KFOE TAF SITES.
LIGHT TO AT TIMES MODERATE SNOW WILL REDEVELOP LATER THIS
AFTERNOON INTO THE EVENING HOURS...WHICH WILL MAY REDUCE
VISIBILITIES BELOW 1SM. KMHK MAY KEEP LIGHT SNOW WITH POTENTIALLY
SOME HEAVIER SNOW DROPPING VISIBILITIES TO 1/4 MILES AT TIMES. THE
SNOW SHOULD END AT ALL TAF SITES AFTER 4Z. CEILINGS WILL VARY FROM
IFR TO MVFR DEPENDING ON SNOWFALL RATES. IFR CEILINGS WILL MOVE IN
THIS EVENING ON THE NORTHWEST SIDE OF THE SURFACE LOW. THE IFR
CEILINGS MAY GRADUALLY RISE TO MVFR CEILINGS LATE TONIGHT.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL MIDNIGHT CST TONIGHT FOR KSZ010>012-
022>024-026-036>040-054>056-058-059.
WINTER STORM WARNING UNTIL 6 PM CST THIS EVENING FOR KSZ008-009-
020-021-034-035.
&&
$$
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1232 AM EST THU FEB 21 2013
...Updated Aviation Discussion...
.Short Term (Tonight through Thursday Night)...
Issued at 300 PM EST Wed Feb 20 2013
...A Brief Period of Wintry Weather Coming North of the I-64
Corridor...
What a mess as far as dealing with winter weather, as our next
system will bring it`s winter weather transition zone right across
our forecast area Thursday afternoon to late Thursday night.
Until then, the main forecast issue tonight will be cloud cover.
Shield of mid/high clouds moving in now is not forecast to last all
night. The RAP is advertising additional lower level clouds moving
in from the north, a low stratus, which right now is associated with
the flow coming off Lake Michigan. Will lean toward the rest of the
guidance, which keeps us clearer, overnight, except over the far
north. Then mid clouds should increase again as the system mentioned
above starts to influence our weather.
The atmosphere will saturate from above as an occluded front
approaches from the west. Deep isentropic ascent ahead of this front
will allow precipitation to start west of the I-65 corridor by late
afternoon. With the onset of this precip, expect temperatures to
drop a couple of degrees, which will allow for a mix of sleet/snow
across the north and cold rain down south. By 00Z, warm air aloft
will help to melt the deep freezing layer, allowing for the chance
for freezing rain across the north. As the night goes on, the warm
air will deepen and expect a transition over the just rain areawide
by around 09Z.
Forecast uncertainty remains high enough to keep us from issuing an
advisory. Went under guidance for temperatures at the surface and
aloft. If model forecast temperatures are true, and it should be
noted that our forecast errors for this forecast time period average
2-3 degrees, than much more of the area will be mostly rain. Based
on this uncertainty, have decided to issue just a special weather
statement on the chance for winter weather and hold off on issuing a
third-period advisory.
.Long Term (Friday through Tuesday Night)...
Issued at 326 PM EST Wed Feb 20 2013
The beginning of the long term period will feature a strong
shortwave pushing north through the Northern Plains. In its wake, a
trough will amplify across the central CONUS this weekend which will
work into the Ohio Valley. Another upper ridge will amplify across
the Ohio Valley ahead of the next system set to affect the region
early next week.
A warm front will be lifting north through the region early Friday
morning, with the associated synoptic forcing/isentropic ascent
lifting north into Ohio. Therefore, precipitation will taper off
from southwest to northeast through the day as a dry slot works
into the region. Temperatures on Friday will be rather warm, as the
surface cold front will remain well off to the west, allowing for
southwesterly winds to aid in a quick warmup in the wake of the
morning precipitation.
The associated cold front will finally push through the region late
Friday into early Saturday. Another shortwave will swing through
the mean trough Saturday morning, which will induce secondary
surface low development across TN/GA. As this wave rides along the
departing cold front, it will act to stall its progress. In fact,
the 12Z suite of guidance is suggesting there may be enough moisture
kicked back into the region to produce some additional precipitation
across the Cumberland area as the shortwave and surface low pass
by. If this moisture were to get far enough north into the cooler
air, then some light freezing rain/drizzle could creep into the
northern Bluegrass region Saturday morning. However, this
probability looks rather low at this point and will leave
precipitation as all rain for now and confined to the far
east/southeast portions of the CWA.
A ridge will build across the region late Saturday through Monday,
providing calm and dry weather conditions. Temperatures will warm
each day through the weekend, as temperatures in the lower 40s on
Saturday warm into the middle 50s by Monday.
Another strong upper level wave will eject out into the Central and
Northern Plains on Monday. This system looks very similar to the
Thursday/Friday system, spreading a slug of precipitation north in
association with a wave of isentropic ascent atop the surface warm
front. This time, however, the cooler air will not be in place
ahead of the approaching warm front, so any and all precipitation
will remain rain. The surface cold front will push through late
Monday night into Tuesday morning, dropping temperatures back into
the upper 40s Tuesday afternoon.
The 20/12Z GFS advertises the surface low tracking across Indiana
and Ohio, which would bring some wrap-around precipitation to
portions of southern Indiana and northern Kentucky Tuesday into
early Wednesday. However, with a strong upper ridge in place, this
system will struggle dropping southeast like the GFS suggests.
Therefore, will favor the ECMWF and GFS ensembles, lifting the
surface low and its associated wrap-around precipitation further
north, thus keeping the forecast dry through the remainder of the
long term period.
&&
.Aviation (06Z TAF Issuance)...
Issued at 1232 AM EST Thu Feb 21 2013
Front half of the upcoming TAF period is fairly quiet as VFR
conditions will hold across the region with a very light
northeasterly surface flow. Clouds will increase throughout the
daytime hours as moisture streams in from the west. Initially dry
atmosphere will take some time to moisten up during the day but
precipitation looks to break out across the TAF sites towards 22/00Z.
Latest guidance continues to show the column moistening up during
the late afternoon hours. As column saturates to near the surface
by the evening hours, the evaporative cooling associated with the
moistening will allow surface temperatures to drop to near or just
below freezing at KSDF and KLEX. Warm air advection aloft will
result in a gradual warming above the sub-freezing layer at the
surface resulting in a profile for freezing rain and sleet to
develop. A mix of freezing rain and sleet looks increasingly likely
at KSDF between 22/02 and 22/06Z before low-level warm air advection
pushes surface temperatures up above freezing resulting in a change
back over to plain rain.
Over at KLEX, models prog stronger surface cooling resulting in a
period of freezing rain likely from 22/00Z through the end of the
TAF period. Depending on the amount of warm air aloft, some sleet is
possible, but it looks like the warm layer aloft will be
sufficiently deep enough to have precip generally in the form of
freezing rain. So for now, will just carry FZRA in the TAF from
22/00Z through the end of the period.
Further south at KBWG, low-level thermal profiles show plenty of
warm air to keep the precipitation as all rain Thursday night.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Short Term.......RJS
Long Term........KJD
Aviation.........MJ
AREA FORECAST DISCUSSION...UPDATED
NWS PITTSBURGH PA
957 PM EST FRI FEB 22 2013
.SYNOPSIS...
A WARM FRONT WILL LIFT NORTHWARD INTO THE AREA TONIGHT. A WEAK
COLD FRONT WILL MOVE ACROSS THE AREA ON SATURDAY...FOLLOWED BY
BUILDING HIGH PRESSURE SUNDAY.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
MADE MINOR ADJUSTMENTS TO OVERNIGHT LOWS USING LATEST LAMP
NUMBERS. HAVE REMOVED MENTION OF FZDZ.
PREVIOUS FORECAST...
THE LATEST RAP MID-LEVEL ANALYSIS INDICATES A CLOSED 500MB LOW
CENTERED ACROSS THE UPPER MIDWEST. AT THE SURFACE...AN OCCLUDED FRONT
EXTENDS FROM THE LOW IN THE TN VALLEY. FROM THE OCCLUDED FRONT...A
WARM EXTENDS EASTWARD INTO NORTH-CENTRAL WV. WITH A DRY LAYER IN
PLACE ABOVE 800MB...ANY LINGERING PRECIPITATION IN WEAK LIFT AHEAD
OF THE FRONT HAS BEEN IN THE FORM OF DRIZZLE OR FREEZING DRIZZLE
ACROSS THE AREA. LOCATIONS NORTH OF PITTSBURGH AND ACROSS THE
LAUREL HIGHLANDS/ALLEGHENY FRONT REMAIN BELOW FREEZING.
TONIGHT...LOW-LEVEL MOISTURE WILL LINGER ACROSS THE AREA NORTH AND
EAST OF PITTSBURGH AS A COLD FRONT APPROACHES FROM THE WEST.
RAP/GFS/NAM SOUNDINGS CONTINUE TO INDICATE A DRY DENDRITIC
GROWTH ZONE WITH A SATURATED LAYER FROM 800MB TO THE SURFACE.
THUS...HAVE CONTINUED MENTIONING OF DZ/FZDZ FOR LOCATIONS NORTH AND
EAST OF PITTSBURGH. TEMPS WILL BE FAIRLY STEADY
OVERNIGHT...RANGING FROM THE LOWER 30S NORTH AND EAST OF
PITTSBURGH TO THE UPPER 30S IN PORTIONS OF EASTERN OHIO AND NORTH-
CENTRAL WV.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/...
A MODEL CONSENSUS INDICATES THAT THE UPPER LOW WILL SHIFT
NORTHEASTWARD INTO THE NORTHERN GREAT LAKES AND A WEAK COLD FRONT
WILL SWING ACROSS THE OHIO VALLEY ON SATURDAY. MEANWHILE...A
SURFACE LOW WILL MOVE FROM THE SOUTHEAST INTO THE MID-
ATLANTIC...PASSING TO THE SOUTHEAST OF THE FORECAST AREA.
DESPITE MODEL AGREEMENT IN THE SYNOPTIC SCALE PATTERN...THERE
STILL LIES SOME UNCERTAINTY IN RESOLVING PRECIPITATION WITH THE
FRONTAL PASSAGE ON SATURDAY.
HAVE ONLY GONE WITH SCHC IN WESTERN PA AND CHC ACROSS THE RIDGES
ON SATURDAY AS THE WEAK FRONT MAY BE ABLE TO PRODUCE A FEW SHOWERS
WHEN IT ENCOUNTERS A BIT MORE AVAILABLE MOISTURE IN WESTERN PA AND
NORTHERN WV. OTHERWISE...WENT DRY IN OHIO. FOR PRECIP
TYPE...MOSTLY RAIN IS FORECAST AS WAA CONTINUES AHEAD OF THE FRONT.
THERE IS STILL SOME UNCERTAINTY AS TO WHETHER COLDER AIR TRAPPED
AT THE SURFACE WILL REMAIN IN PLACE NORTH OF PITTSBURGH AND ACROSS
THE RIDGES...SO HAVE THE MENTION OF SCHC OR CHC FZRA THERE. FOR
TEMPS...SIDED WITH THE WARMER MAV...WITH HIGHS RANGING FROM THE
LOWER TO MID 40S ACROSS MUCH OF THE AREA.
SATURDAY NIGHT THROUGH MONDAY...THE FRONT WILL PASS EAST OF THE
AREA SAT NIGHT WITH THE UPPER LEVEL LOW PASSING NORTH OF THE AREA
ON SUNDAY. HIGH PRESSURE WILL THEN BUILD IN FROM THE SOUTHWEST
SUNDAY NIGHT INTO MONDAY. IN A CYCLONIC MID-LEVEL FLOW SAT NIGHT THAT
WILL BECOME MORE NORTHWESTERLY ON SUN...HAVE CHC POPS ACROSS THE
I-80 CORRIDOR AND WITH UPSLOPING FOR THE LAUREL
HIGHLANDS/ALLEGHENY FRONT. A DRY FORECAST IS IN PLACE SUN NIGHT
INTO MONDAY AS THE HIGH MOVES OVER THE REGION. TEMPS WILL BE A FEW
DEGREES BELOW NORMAL IN THE WAKE OF THE FRONT ON SUNDAY BEFORE
MODERATING TO 5 TO 10 DEGREES ABOVE NORMAL ON MONDAY.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
H5 RDG AXIS WILL MOVE ACRS RGN MON NGT IN ADVC OF A STRONG CLOSED
UPR LOW OVER THE SRN PLNS. AS THE WAVE APRCHS LATE MON NGT...WARM
AIR ADVCTN WILL DVLP IN EARNEST...PROVIDING SGFNT MSTR FOR WDSPRD
PCPN. LGT PCPN XPCD TO SPREAD NEWD LATE MON NGT.
CVRG OF PCPN WILL INCR ON TUE AS THE NEGATIVELY-TILTED WAVE
CROSSES THE RGN. GIVEN CONSISTENT FCST AMONG THE MODELS AND
PERSISTENT MEXMOS PCPN SIGNAL ON TUE...CATEGORICAL POPS WERE
INCLUDED ALL ZONES ON TUE. DRY SLOT XPCD TO BRING END TO PCPN TUE
NGT.
EXACT EVOLUTION OF UPR AIR PATTERN THEREAFTER IS LESS CERTAIN...
BUT H5 TROF XPCD TO RMN OVER ERN CONUS. RESULT WILL BE PERSISTENT
COLDER AIR AND OCNL SNOW SHWRS AS WLY-NWLY LOW-LVL FLOW DOMINATES
THE RGN.
&&
.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
OVERCAST CEILINGS CAN BE EXPECTED THROUGH THE NIGHT WITH IFR
STRATUS CEILINGS ACROSS THE NORTH AND GENERAL MVFR CEILINGS
ACROSS THE SOUTH. LITTLE OR NO PRECIPITATION IS EXPECTED OVERNIGHT
WHILE SOME PATCHY DRIZZLE CAN NOT BE RULED OUT. CEILINGS WILL
IMPROVE SATURDAY WITH THE HEATING OF THE DAY CAUSING ALL PORTS
TO LIFT INTO VFR BROKEN CEILINGS.
.OUTLOOK.../SATURDAY THROUGH TUESDAY/...
IFR WEATHER IS POSSIBLE MONDAY NIGHT INTO TUESDAY WITH THE NEXT
WEATHER SYSTEM...OTHERWISE GENERAL VFR CONDITIONS CAN BE EXPECTED
FOR THE REMAINDER OF THE EXTENDED PERIOD.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR
MDZ001.
OH...NONE.
PA...WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR
PAZ007>009-015-016-022-023.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
929 PM EST FRI FEB 22 2013
.SYNOPSIS...
A WARM FRONT WILL LIFT NORTHWARD INTO THE AREA TONIGHT. A WEAK
COLD FRONT WILL MOVE ACROSS THE AREA ON SATURDAY...FOLLOWED BY
BUILDING HIGH PRESSURE SUNDAY.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
MADE MINOR ADJUSTMENTS TO OVERNIGHT LOWS USING LATEST LAMP
NUMBERS. WILL CONTINUE WITH ADV UNTIL 10PM AS TEMPS IN THE REGION
ARE STILL BELOW FREEZING AND THERE MAY BE AREAS OF FREEZING DRIZZLE.
PREVIOUS FORECAST...
THE LATEST RAP MID-LEVEL ANALYSIS INDICATES A CLOSED 500MB LOW
CENTERED ACROSS THE UPPER MIDWEST. AT THE SURFACE...AN OCCLUDED FRONT
EXTENDS FROM THE LOW IN THE TN VALLEY. FROM THE OCCLUDED FRONT...A
WARM EXTENDS EASTWARD INTO NORTH-CENTRAL WV. WITH A DRY LAYER IN
PLACE ABOVE 800MB...ANY LINGERING PRECIPITATION IN WEAK LIFT AHEAD
OF THE FRONT HAS BEEN IN THE FORM OF DRIZZLE OR FREEZING DRIZZLE
ACROSS THE AREA. LOCATIONS NORTH OF PITTSBURGH AND ACROSS THE
LAUREL HIGHLANDS/ALLEGHENY FRONT REMAIN BELOW FREEZING.
TONIGHT...LOW-LEVEL MOISTURE WILL LINGER ACROSS THE AREA NORTH AND
EAST OF PITTSBURGH AS A COLD FRONT APPROACHES FROM THE WEST.
RAP/GFS/NAM SOUNDINGS CONTINUE TO INDICATE A DRY DENDRITIC
GROWTH ZONE WITH A SATURATED LAYER FROM 800MB TO THE SURFACE.
THUS...HAVE CONTINUED MENTIONING OF DZ/FZDZ FOR LOCATIONS NORTH AND
EAST OF PITTSBURGH. TEMPS WILL BE FAIRLY STEADY
OVERNIGHT...RANGING FROM THE LOWER 30S NORTH AND EAST OF
PITTSBURGH TO THE UPPER 30S IN PORTIONS OF EASTERN OHIO AND NORTH-
CENTRAL WV.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/...
A MODEL CONSENSUS INDICATES THAT THE UPPER LOW WILL SHIFT
NORTHEASTWARD INTO THE NORTHERN GREAT LAKES AND A WEAK COLD FRONT
WILL SWING ACROSS THE OHIO VALLEY ON SATURDAY. MEANWHILE...A
SURFACE LOW WILL MOVE FROM THE SOUTHEAST INTO THE MID-
ATLANTIC...PASSING TO THE SOUTHEAST OF THE FORECAST AREA.
DESPITE MODEL AGREEMENT IN THE SYNOPTIC SCALE PATTERN...THERE
STILL LIES SOME UNCERTAINTY IN RESOLVING PRECIPITATION WITH THE
FRONTAL PASSAGE ON SATURDAY.
HAVE ONLY GONE WITH SCHC IN WESTERN PA AND CHC ACROSS THE RIDGES
ON SATURDAY AS THE WEAK FRONT MAY BE ABLE TO PRODUCE A FEW SHOWERS
WHEN IT ENCOUNTERS A BIT MORE AVAILABLE MOISTURE IN WESTERN PA AND
NORTHERN WV. OTHERWISE...WENT DRY IN OHIO. FOR PRECIP
TYPE...MOSTLY RAIN IS FORECAST AS WAA CONTINUES AHEAD OF THE FRONT.
THERE IS STILL SOME UNCERTAINTY AS TO WHETHER COLDER AIR TRAPPED
AT THE SURFACE WILL REMAIN IN PLACE NORTH OF PITTSBURGH AND ACROSS
THE RIDGES...SO HAVE THE MENTION OF SCHC OR CHC FZRA THERE. FOR
TEMPS...SIDED WITH THE WARMER MAV...WITH HIGHS RANGING FROM THE
LOWER TO MID 40S ACROSS MUCH OF THE AREA.
SATURDAY NIGHT THROUGH MONDAY...THE FRONT WILL PASS EAST OF THE
AREA SAT NIGHT WITH THE UPPER LEVEL LOW PASSING NORTH OF THE AREA
ON SUNDAY. HIGH PRESSURE WILL THEN BUILD IN FROM THE SOUTHWEST
SUNDAY NIGHT INTO MONDAY. IN A CYCLONIC MID-LEVEL FLOW SAT NIGHT THAT
WILL BECOME MORE NORTHWESTERLY ON SUN...HAVE CHC POPS ACROSS THE
I-80 CORRIDOR AND WITH UPSLOPING FOR THE LAUREL
HIGHLANDS/ALLEGHENY FRONT. A DRY FORECAST IS IN PLACE SUN NIGHT
INTO MONDAY AS THE HIGH MOVES OVER THE REGION. TEMPS WILL BE A FEW
DEGREES BELOW NORMAL IN THE WAKE OF THE FRONT ON SUNDAY BEFORE
MODERATING TO 5 TO 10 DEGREES ABOVE NORMAL ON MONDAY.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
H5 RDG AXIS WILL MOVE ACRS RGN MON NGT IN ADVC OF A STRONG CLOSED
UPR LOW OVER THE SRN PLNS. AS THE WAVE APRCHS LATE MON NGT...WARM
AIR ADVCTN WILL DVLP IN EARNEST...PROVIDING SGFNT MSTR FOR WDSPRD
PCPN. LGT PCPN XPCD TO SPREAD NEWD LATE MON NGT.
CVRG OF PCPN WILL INCR ON TUE AS THE NEGATIVELY-TILTED WAVE
CROSSES THE RGN. GIVEN CONSISTENT FCST AMONG THE MODELS AND
PERSISTENT MEXMOS PCPN SIGNAL ON TUE...CATEGORICAL POPS WERE
INCLUDED ALL ZONES ON TUE. DRY SLOT XPCD TO BRING END TO PCPN TUE
NGT.
EXACT EVOLUTION OF UPR AIR PATTERN THEREAFTER IS LESS CERTAIN...
BUT H5 TROF XPCD TO RMN OVER ERN CONUS. RESULT WILL BE PERSISTENT
COLDER AIR AND OCNL SNOW SHWRS AS WLY-NWLY LOW-LVL FLOW DOMINATES
THE RGN.
&&
.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
OVERCAST CEILINGS CAN BE EXPECTED THROUGH THE NIGHT WITH IFR
STRATUS CEILINGS ACROSS THE NORTH AND GENERAL MVFR CEILINGS
ACROSS THE SOUTH. LITTLE OR NO PRECIPITATION IS EXPECTED OVERNIGHT
WHILE SOME PATCHY DRIZZLE CAN NOT BE RULED OUT. CEILINGS WILL
IMPROVE SATURDAY WITH THE HEATING OF THE DAY CAUSING ALL PORTS
TO LIFT INTO VFR BROKEN CEILINGS.
.OUTLOOK.../SATURDAY THROUGH TUESDAY/...
IFR WEATHER IS POSSIBLE MONDAY NIGHT INTO TUESDAY WITH THE NEXT
WEATHER SYSTEM...OTHERWISE GENERAL VFR CONDITIONS CAN BE EXPECTED
FOR THE REMAINDER OF THE EXTENDED PERIOD.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR
MDZ001.
OH...NONE.
PA...WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR
PAZ007>009-015-016-022-023.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS PITTSBURGH PA
659 PM EST FRI FEB 22 2013
.SYNOPSIS...
A WARM FRONT WILL LIFT NORTHWARD INTO THE AREA TONIGHT. A WEAK
COLD FRONT WILL MOVE ACROSS THE AREA ON SATURDAY...FOLLOWED BY
BUILDING HIGH PRESSURE SUNDAY.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
MADE MINOR ADJUSTMENTS TO OVERNIGHT LOWS USING LATEST LAMP
NUMBERS. WILL CONTINUE WITH ADV UNTIL 10PM AS TEMPS IN THE REGION
ARE STILL BELOW FREEZING AND THERE MAY BE AREAS OF FREEZING DRIZZLE.
PREVIOUS FORECAST...
THE LATEST RAP MID-LEVEL ANALYSIS INDICATES A CLOSED 500MB LOW
CENTERED ACROSS THE UPPER MIDWEST. AT THE SURFACE...AN OCCLUDED FRONT
EXTENDS FROM THE LOW IN THE TN VALLEY. FROM THE OCCLUDED FRONT...A
WARM EXTENDS EASTWARD INTO NORTH-CENTRAL WV. WITH A DRY LAYER IN
PLACE ABOVE 800MB...ANY LINGERING PRECIPITATION IN WEAK LIFT AHEAD
OF THE FRONT HAS BEEN IN THE FORM OF DRIZZLE OR FREEZING DRIZZLE
ACROSS THE AREA. LOCATIONS NORTH OF PITTSBURGH AND ACROSS THE
LAUREL HIGHLANDS/ALLEGHENY FRONT REMAIN BELOW FREEZING.
TONIGHT...LOW-LEVEL MOISTURE WILL LINGER ACROSS THE AREA NORTH AND
EAST OF PITTSBURGH AS A COLD FRONT APPROACHES FROM THE WEST.
RAP/GFS/NAM SOUNDINGS CONTINUE TO INDICATE A DRY DENDRITIC
GROWTH ZONE WITH A SATURATED LAYER FROM 800MB TO THE SURFACE.
THUS...HAVE CONTINUED MENTIONING OF DZ/FZDZ FOR LOCATIONS NORTH AND
EAST OF PITTSBURGH. TEMPS WILL BE FAIRLY STEADY
OVERNIGHT...RANGING FROM THE LOWER 30S NORTH AND EAST OF
PITTSBURGH TO THE UPPER 30S IN PORTIONS OF EASTERN OHIO AND NORTH-
CENTRAL WV.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/...
A MODEL CONSENSUS INDICATES THAT THE UPPER LOW WILL SHIFT
NORTHEASTWARD INTO THE NORTHERN GREAT LAKES AND A WEAK COLD FRONT
WILL SWING ACROSS THE OHIO VALLEY ON SATURDAY. MEANWHILE...A
SURFACE LOW WILL MOVE FROM THE SOUTHEAST INTO THE MID-
ATLANTIC...PASSING TO THE SOUTHEAST OF THE FORECAST AREA.
DESPITE MODEL AGREEMENT IN THE SYNOPTIC SCALE PATTERN...THERE
STILL LIES SOME UNCERTAINTY IN RESOLVING PRECIPITATION WITH THE
FRONTAL PASSAGE ON SATURDAY.
HAVE ONLY GONE WITH SCHC IN WESTERN PA AND CHC ACROSS THE RIDGES
ON SATURDAY AS THE WEAK FRONT MAY BE ABLE TO PRODUCE A FEW SHOWERS
WHEN IT ENCOUNTERS A BIT MORE AVAILABLE MOISTURE IN WESTERN PA AND
NORTHERN WV. OTHERWISE...WENT DRY IN OHIO. FOR PRECIP
TYPE...MOSTLY RAIN IS FORECAST AS WAA CONTINUES AHEAD OF THE FRONT.
THERE IS STILL SOME UNCERTAINTY AS TO WHETHER COLDER AIR TRAPPED
AT THE SURFACE WILL REMAIN IN PLACE NORTH OF PITTSBURGH AND ACROSS
THE RIDGES...SO HAVE THE MENTION OF SCHC OR CHC FZRA THERE. FOR
TEMPS...SIDED WITH THE WARMER MAV...WITH HIGHS RANGING FROM THE
LOWER TO MID 40S ACROSS MUCH OF THE AREA.
SATURDAY NIGHT THROUGH MONDAY...THE FRONT WILL PASS EAST OF THE
AREA SAT NIGHT WITH THE UPPER LEVEL LOW PASSING NORTH OF THE AREA
ON SUNDAY. HIGH PRESSURE WILL THEN BUILD IN FROM THE SOUTHWEST
SUNDAY NIGHT INTO MONDAY. IN A CYCLONIC MID-LEVEL FLOW SAT NIGHT THAT
WILL BECOME MORE NORTHWESTERLY ON SUN...HAVE CHC POPS ACROSS THE
I-80 CORRIDOR AND WITH UPSLOPING FOR THE LAUREL
HIGHLANDS/ALLEGHENY FRONT. A DRY FORECAST IS IN PLACE SUN NIGHT
INTO MONDAY AS THE HIGH MOVES OVER THE REGION. TEMPS WILL BE A FEW
DEGREES BELOW NORMAL IN THE WAKE OF THE FRONT ON SUNDAY BEFORE
MODERATING TO 5 TO 10 DEGREES ABOVE NORMAL ON MONDAY.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
H5 RDG AXIS WILL MOVE ACRS RGN MON NGT IN ADVC OF A STRONG CLOSED
UPR LOW OVER THE SRN PLNS. AS THE WAVE APRCHS LATE MON NGT...WARM
AIR ADVCTN WILL DVLP IN EARNEST...PROVIDING SGFNT MSTR FOR WDSPRD
PCPN. LGT PCPN XPCD TO SPREAD NEWD LATE MON NGT.
CVRG OF PCPN WILL INCR ON TUE AS THE NEGATIVELY-TILTED WAVE
CROSSES THE RGN. GIVEN CONSISTENT FCST AMONG THE MODELS AND
PERSISTENT MEXMOS PCPN SIGNAL ON TUE...CATEGORICAL POPS WERE
INCLUDED ALL ZONES ON TUE. DRY SLOT XPCD TO BRING END TO PCPN TUE
NGT.
EXACT EVOLUTION OF UPR AIR PATTERN THEREAFTER IS LESS CERTAIN...
BUT H5 TROF XPCD TO RMN OVER ERN CONUS. RESULT WILL BE PERSISTENT
COLDER AIR AND OCNL SNOW SHWRS AS WLY-NWLY LOW-LVL FLOW DOMINATES
THE RGN.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MEDIUM...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
LOW TO MEDIUM CONFIDENCE FORECAST.
AREA OF FZRA CONTINUES TO EXIT QUICKLY WITH PATCHY DRIZZLE AND
FREEZING DRIZZLE IN ITS WAKE. BRIEF IFR WX WILL LAST AT PIT METRO
TERMINALS AND FKL/DUJ THRU 20Z. DRY SLOT THAT IS RACING NE FROM
SERN OH AND WV PER LOW LEVEL DOWNSLOPE WINDS AND SW FLOW ALOFT
REACHES ZZV - PIT - LBE THIS AFTN. BKN VFR CIGS WILL CARRY THROUGH
THE EVENING HOURS AT THE AFOREMENTIONED AIRPORTS.
HARDEST PART OF THE FORECAST IS WHAT WILL HAPPEN OVERNIGHT. ALL OF
THE STATISTICAL GUIDANCE YIELDS MVFR / IFR CIGS WHILE UPSTREAM OBS
SAY IT WILL BE VFR. PLAYED THE OPTIMISTIC ROLE FOR MOST
TERMINALS...SAVE FOR FKL/DUJ/ZZV WHERE MVFR CIGS SHOULD OCCUR FOR AT
LEAST PART OF THE NIGHT. ANY MVFR CIGS LIFT BY MID MRNG DUE TO
LIGHT SW WINDS.
WHERE TAFS COULD GO WRONG:
- MVFR CIGS COULD LINGER THROUGH THE AFTN
- MVFR/IFR CIGS MAY DEVELOP DURING THE OVERNIGHT HOURS AREA WIDE
- MVFR CIGS COULD TAKE UNTIL 15-17Z TO LIFT
.OUTLOOK.../SATURDAY THROUGH TUESDAY/...
IFR WEATHER IS POSSIBLE MONDAY NIGHT INTO TUESDAY WITH THE NEXT
WEATHER SYSTEM.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR
MDZ001.
OH...NONE.
PA...WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR
PAZ007>009-015-016-022-023.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
359 PM EST THU FEB 21 2013
.SYNOPSIS...
ISSUED AT 330 PM EST THU FEB 21 2013
SNOW WILL SPREAD NORTHEAST ACROSS THE AREA OVERNIGHT INTO FRIDAY
MORNING. A QUICK 1 TO 2 INCHES OF SNOW MAY AFFECT THE FRIDAY MORNING
COMMUTE. THIS WILL BE FOLLOWED BY A TRANSITION TO FREEZING DRIZZLE
LATER IN THE DAY. A CHANCE OF WINTRY PRECIPITATION WILL PERSIST
THROUGH SATURDAY NIGHT. THE NEXT CHANCES FOR PRECIPITATION WILL BE
MONDAY NIGHT AND TUESDAY...WHEN A MIX OF RAIN AND SNOW IS EXPECTED.
TEMPERATURES WILL MODERATE NEXT WEEK WITH HIGHS REACHING THE UPPER
30S.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 330 PM EST THU FEB 21 2013
WILL BE ISSUING A WINTER WEATHER ADVISORY FOR OUR SOUTHERN CWFA TO
ACCOUNT FOR POSSIBLE BRIEF INTENSE SNOWFALL DURING THE FRIDAY
MORNING COMMUTE. CALIBRATED SREF GUIDANCE SHOWS GREATER THAN 1 INCH
PER HOUR SNOWFALL PROBABILITIES ACROSS OUR SOUTHERN COUNTY WARNING
AREA IN THE 12-15Z TIMEFRAME FRIDAY. ALSO LATEST GRR SNOWTOOL
GUIDANCE FROM THE RAP SUGGESTS THAT 1"/HR RATES WILL BE POSSIBLE
AFTER 10Z. ADVISORY WILL BE COMING OUT SHORTLY.
AFTER THIS INITIAL BURST OF SNOWFALL...AGREE WITH THE PREVIOUS
DISCUSSION THAT IMPACTS SHOULD BE MINOR. THE RESPONSIBLE SYSTEM
CURRENTLY IN THE PLAINS WILL FILL AS IT SHEARS NORTHEAST. BEHIND THE
NARROW BUT POTENTIALLY INTENSE BAND OF WARM ADVECTION SNOW...ALL BUT
THE EXTREME NORTHERN PART OF THE FORECAST AREA DESATURATES IN THE
DGZ DURING THE LATE MORNING...MEANING A TRANSITION TO FREEZING
DRIZZLE AND THEN POSSIBLY DRIZZLE AS SURFACE TEMPERATURES WARM. ICE
ACCUMULATION IS EXPECTED TO BE MINIMAL... ESPECIALLY WITH THE
MITIGATING EFFECTS OF SNOW COVER...RESIDUAL SALT...AND DAYTIME
INSOLATION ALL DISCUSSED IN THE PREVIOUS AFD.
.LONG TERM...(SUNDAY THROUGH THURSDAY)
ISSUED AT 330 PM EST THU FEB 21 2013
A HIGH PRESSURE RIDGE WILL PRODUCE DRY WX WITH SEASONABLY COOL
TEMPERATURES SUNDAY THROUGH SUNDAY NIGHT. LOW PRESSURE TRACKING NE
INTO OUR REGION WILL BRING A SLIGHT CHANCE FOR A MIX OF LIGHT RAIN
AND LIGHT SNOW AS EARLY AS MONDAY BASED ON 12Z GFS GUIDANCE.
HOWEVER THE MUCH BETTER CHANCE FOR MIXED PCPN SHOULD HOLD OFF UNTIL
LATE MONDAY NIGHT AND TUESDAY AS SUGGESTED BY THE SLOWER AND
PREFERRED ECMWF 12Z GUIDANCE SOLUTION (WHICH IS CONSISTENT WITH PCPN
TIMING FROM THE 00Z RUN).
TEMPS WILL UNDERGO A GRADUAL MODERATING TREND DURING THE EARLY TO
MIDDLE PORTION OF NEXT WEEK WITH MAX TEMPS EXPECTED TO REACH THE
UPPER 30S TO LOWER 40S BY TUESDAY AND WEDNESDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY)
ISSUED AT 1225 PM EST THU FEB 21 2013
MVFR CONDITIONS WILL CONTINUE AT ALL THE TERMINALS THIS AFTERNOON
AND EVENING DUE TO LOW CLOUDS WITH CLOUD BASES OF 1.5 TO 2 KFT AGL.
CONDITIONS WILL DETERIORATE FROM MVFR TO IFR DURING THE EARLY
MORNING HOURS FRIDAY AS A BAND OF SNOW MOVES IN FROM SW TO NE.
IFR/LIFR CONDITIONS WILL CONTINUE FRIDAY MORNING THROUGH EARLY
FRIDAY AFTERNOON AS CIGS LOWER AND SNOW CONTINUES.
THERE IS ALSO SOME POTENTIAL FOR FREEZING DRIZZLE FROM MID MORNING
FRIDAY THROUGH 18Z FRIDAY MAINLY FOR THE TERMINALS ALONG THE I-94
CORRIROR. NOT ENOUGH POTENTIAL IN THIS TO WARRANT INCLUSION IN THE
TERMINAL FCSTS JUST YET... BUT WE WILL CONTINUE TO MONITOR FOR
THIS POTENTIAL.
&&
.MARINE...
ISSUED AT 359 PM EST THU FEB 21 2013
AFTER FURTHER CONSIDERATION...ISSUED A NEW SMALL CRAFT ADVISORY BEGINNING
TONIGHT TO ACCOUNT FOR STRENGTHENING EAST WINDS TOWARDS MORNING. ALTHOUGH
WAVE GROWTH WILL BE LIMITED SOMEWHAT BY POOR FETCH...SUSTAINED WINDS
WELL IN EXCESS OF 20 KTS TOWARDS SUNRISE WILL GREATLY INCREASE THE
HAZARD.
&&
.HYDROLOGY...
ISSUED AT 330 PM EST THU FEB 21 2013
WITH ADDITIONAL QPF EXPECTED TO STAY WELL UNDER HALF AN INCH...THERE
ARE NO CONCERNS AT THIS TIME.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY FROM 4 AM TO 1 PM EST FRIDAY FOR MIZ050-
056>059-064>067-071>074.
LM...SMALL CRAFT ADVISORY FROM 1 AM FRIDAY TO 5 PM EST SATURDAY FOR
LMZ844>849.
&&
$$
SYNOPSIS...TJT
SHORT TERM...TJT
LONG TERM...LAURENS
AVIATION...LAURENS
HYDROLOGY...TJT
MARINE...TJT
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
330 PM EST THU FEB 21 2013
.SYNOPSIS...
ISSUED AT 330 PM EST THU FEB 21 2013
SNOW WILL SPREAD NORTHEAST ACROSS THE AREA OVERNIGHT INTO FRIDAY
MORNING. A QUICK 1 TO 2 INCHES OF SNOW MAY AFFECT THE FRIDAY MORNING
COMMUTE. THIS WILL BE FOLLOWED BY A TRANSITION TO FREEZING DRIZZLE
LATER IN THE DAY. A CHANCE OF WINTRY PRECIPITATION WILL PERSIST
THROUGH SATURDAY NIGHT. THE NEXT CHANCES FOR PRECIPITATION WILL BE
MONDAY NIGHT AND TUESDAY...WHEN A MIX OF RAIN AND SNOW IS EXPECTED.
TEMPERATURES WILL MODERATE NEXT WEEK WITH HIGHS REACHING THE UPPER
30S.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 330 PM EST THU FEB 21 2013
WILL BE ISSUING A WINTER WEATHER ADVISORY FOR OUR SOUTHERN CWFA TO
ACCOUNT FOR POSSIBLE BRIEF INTENSE SNOWFALL DURING THE FRIDAY
MORNING COMMUTE. CALIBRATED SREF GUIDANCE SHOWS GREATER THAN 1 INCH
PER HOUR SNOWFALL PROBABILITIES ACROSS OUR SOUTHERN COUNTY WARNING
AREA IN THE 12-15Z TIMEFRAME FRIDAY. ALSO LATEST GRR SNOWTOOL
GUIDANCE FROM THE RAP SUGGESTS THAT 1"/HR RATES WILL BE POSSIBLE
AFTER 10Z. ADVISORY WILL BE COMING OUT SHORTLY.
AFTER THIS INITIAL BURST OF SNOWFALL...AGREE WITH THE PREVIOUS
DISCUSSION THAT IMPACTS SHOULD BE MINOR. THE RESPONSIBLE SYSTEM
CURRENTLY IN THE PLAINS WILL FILL AS IT SHEARS NORTHEAST. BEHIND THE
NARROW BUT POTENTIALLY INTENSE BAND OF WARM ADVECTION SNOW...ALL BUT
THE EXTREME NORTHERN PART OF THE FORECAST AREA DESATURATES IN THE
DGZ DURING THE LATE MORNING...MEANING A TRANSITION TO FREEZING
DRIZZLE AND THEN POSSIBLY DRIZZLE AS SURFACE TEMPERATURES WARM. ICE
ACCUMULATION IS EXPECTED TO BE MINIMAL... ESPECIALLY WITH THE
MITIGATING EFFECTS OF SNOW COVER...RESIDUAL SALT...AND DAYTIME
INSOLATION ALL DISCUSSED IN THE PREVIOUS AFD.
.LONG TERM...(SUNDAY THROUGH THURSDAY)
ISSUED AT 330 PM EST THU FEB 21 2013
A HIGH PRESSURE RIDGE WILL PRODUCE DRY WX WITH SEASONABLY COOL
TEMPERATURES SUNDAY THROUGH SUNDAY NIGHT. LOW PRESSURE TRACKING NE
INTO OUR REGION WILL BRING A SLIGHT CHANCE FOR A MIX OF LIGHT RAIN
AND LIGHT SNOW AS EARLY AS MONDAY BASED ON 12Z GFS GUIDANCE.
HOWEVER THE MUCH BETTER CHANCE FOR MIXED PCPN SHOULD HOLD OFF UNTIL
LATE MONDAY NIGHT AND TUESDAY AS SUGGESTED BY THE SLOWER AND
PREFERRED ECMWF 12Z GUIDANCE SOLUTION (WHICH IS CONSISTENT WITH PCPN
TIMING FROM THE 00Z RUN).
TEMPS WILL UNDERGO A GRADUAL MODERATING TREND DURING THE EARLY TO
MIDDLE PORTION OF NEXT WEEK WITH MAX TEMPS EXPECTED TO REACH THE
UPPER 30S TO LOWER 40S BY TUESDAY AND WEDNESDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY)
ISSUED AT 1225 PM EST THU FEB 21 2013
MVFR CONDITIONS WILL CONTINUE AT ALL THE TERMINALS THIS AFTERNOON
AND EVENING DUE TO LOW CLOUDS WITH CLOUD BASES OF 1.5 TO 2 KFT AGL.
CONDITIONS WILL DETERIORATE FROM MVFR TO IFR DURING THE EARLY
MORNING HOURS FRIDAY AS A BAND OF SNOW MOVES IN FROM SW TO NE.
IFR/LIFR CONDITIONS WILL CONTINUE FRIDAY MORNING THROUGH EARLY
FRIDAY AFTERNOON AS CIGS LOWER AND SNOW CONTINUES.
THERE IS ALSO SOME POTENTIAL FOR FREEZING DRIZZLE FROM MID MORNING
FRIDAY THROUGH 18Z FRIDAY MAINLY FOR THE TERMINALS ALONG THE I-94
CORRIROR. NOT ENOUGH POTENTIAL IN THIS TO WARRANT INCLUSION IN THE
TERMINAL FCSTS JUST YET... BUT WE WILL CONTINUE TO MONITOR FOR
THIS POTENTIAL.
&&
.MARINE...
ISSUED AT 330 PM EST THU FEB 21 2013
BASED ON WEBCAMS AND LATEST LOCAL RUN OF THE GLERL...CANCELLED THE
SMALL CRAFT ADVISORY.
&&
.HYDROLOGY...
ISSUED AT 330 PM EST THU FEB 21 2013
WITH ADDITIONAL QPF EXPECTED TO STAY WELL UNDER HALF AN INCH...THERE
ARE NO CONCERNS AT THIS TIME.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...TJT
SHORT TERM...TJT
LONG TERM...LAURENS
AVIATION...LAURENS
HYDROLOGY...TJT
MARINE...TJT
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
548 AM CST THU FEB 21 2013
.UPDATE...FOR 12Z AVIATION DISCUSSION BELOW
&&
.DISCUSSION.../ISSUED 404 AM CST THU FEB 21 2013/
TWO WEATHER CONCERNS COMING UP IN THE NEXT WEEK. FIRST WILL BE
SNOW FROM THURSDAY NIGHT THROUGH FRIDAY NIGHT...WITH ANOTHER
POTENTIAL SNOW MAKER FOR NEXT WEEK. MODEL AGREEMENT REMAINS HIGH
WITH THE FIRST SYSTEM...BUT THERE REMAINS QUITE A BIT OF SPREAD
WITH SYSTEM TWO...ESPECIALLY IN TERMS OF TIMING.
OUR FIRST WAVE IS EASILY IDENTIFIABLE THIS MORNING ON WATER VAPOR
IMAGERY THIS NEAR ALBUQUERQUE...WITH AN IMPRESSIVE CLUSTER OF
THUNDERSTORMS MOVING NORTH OUT OF OK THAT IS ON THE NOSE OF 90 KT
MID LEVEL JET ROUNDING THE BASE OF THE TROUGH. UP HERE...THE MPX
AREA REMAINS UNDER THE INFLUENCE OF A 1040 MB ARCTIC HIGH CENTERED
OVER NW ONTARIO...WITH A RIDGE AXIS DOWN THE ST. CROIX/MIS RIVER
VALLEYS. THIS HIGH IS THE SOURCE FOR OUR LOW LEVEL AIR...WITH
DEWPS HOVERING AROUND ZERO AS A RESULT. TEMPERATURES ARE ALSO A
FEW DEGREES ON EITHER SIDE OF ZERO AND HAVE BEEN HELD IN CHECK BY
A THIN BLANKET OF CIRRUS. FOR TODAY...THE HIGH WILL KEEP ANY
PRECIP SOUTH OF THE MPX CWA...WITH THICKENING HIGH CLOUDS HELPING
TO KEEP TEMPERATURES A LITTLE BIT MORE UNIFORM THAN WHAT WAS SEEN
YESTERDAY.
FOR US...THE HEAVY SHIELD OF PRECIP MOVING ACROSS SRN KANSAS WILL
BE WHAT BRINGS THIS REGION MOST OF ITS SNOW. AT 3AM...THIS PRECIP
WAS STILL ALL SOUTH OF I-70...SO IT WILL BE A WHILE BEFORE
REACHING THE I-90 CORRIDOR. MODELS HAVE MAINTAINED GOOD AGREEMENT
WITH THEIR HANDLING OF THE SYSTEM...WITH THE ONE OUTLIER
CONTINUING TO BE THE NAM...WHICH IS STILL RUNNING A BIT HIGHER
WITH QPF ACROSS MN/WRN WI...THOUGH IT HAS COME DOWN MORE IN LINE
WITH THE ECMWF/GFS/SREF/GEM. FOR TIMING PRECIP WITH THIS SYSTEM...
FAVORED THE SREF TIMING AS IT IS BASICALLY IN LINE WITH EVERYTHING
ELSE AND DOES ACCOUNT FOR SOME MINIMAL SPREAD. FOR QPF...A BLEND
OF THE ECMWF/GFS/SREF WAS USED...ALONG WITH SNOW RATIOS OF
15-16:1.
SO WHAT CHANGED? FIRST...SLOWED EVEN FURTHER HOW QUICKLY THINGS
MOVE NORTH TONIGHT...WITH NO CATEGORICAL POPS IN THE SOUTH UNTIL
AFTER 3Z AND DELAYING THE START OF SNOW ACROSS THE FAR NRN CWA
UNTIL AFTER 9Z. QPF/SNOWFALL WITH THIS FORECAST HAD ONLY A SLIGHT
NUDGE DOWN IN BOTH. CURRENT GRIDS HAVE 4-5 INCHES ALONG AND SOUTH
OF A ST. JAMES...TO MANKATO...TO RICE LAKE LINE. 3 TO 4 INCHES ARE
CURRENTLY INDICATED NORTHWEST TO A REDWOOD FALLS...TO
MONTICELLO...TO CAMBRIDGE LINE...WHICH IS BASICALLY AS FAR NW AS
CURRENT ADVISORY GOES...SO NO AREAL EXPANSIONS WERE NEEDED WITH IT
TONIGHT. PART OF THE REASON TOTALS ARE AS HIGH AS THEY ARE IS THAT
AS THIS SYSTEM SLOWLY FILLS FRIDAY INTO SATURDAY...LIGHT SNOW WILL
PERSIST ACROSS MUCH OF THE AREA RIGHT THROUGH FRIDAY
NIGHT...HELPING BOOST SNOW TOTALS SOME...ESPECIALLY ACROSS WRN WI.
LEFT STARTING/END TIMES UNCHANGED WITH ADVY...BUT WITH SNOW LIKELY
TO PERSIST THROUGH FRIDAY NIGHT...EXTENDING THE ADVISORY INTO
SATURDAY MORNING ACROSS ERN AREAS WILL BE SOMETHING FUTURE SHIFTS
WILL NEED TO THINK ABOUT.
MODELS SHOW SNOW FINALLY CUTTING OFF DURING THE DAY SATURDAY AS
UPPER LOW BEGINS TO EJECT EAST ACROSS THE GREAT LAKES...ALLOWING
SFC RIDGE TO MOVE IN. GOOD NEWS THOUGH IS WE WILL NOT SEE A GOOD
PUNCH OF ARCTIC AIR BEHIND THIS SYSTEM...SO WILL MAINTAIN HIGHS IN
THE 20S/30S INTO THE WEEKEND.
NEXT SYSTEM TO POTENTIALLY IMPACT THE AREA DURING THE FIRST HALF
OF NEXT WEEK CAN BE FOUND OUT IN THE FAR WEST END OF THE ALEUTIAN
ISLAND CHAIN AT THE MOMENT. STILL SEE A DECENT AMOUNT OF SPREAD
WITH THIS SYSTEM...WITH THE GFS PUSHING SNOW IN BY SUNDAY
NIGHT...WHILE THE ECMWF/GEM DO NOT REALLY BRING ANYTHING IN UNTIL
TUESDAY. THE GEFS MEAN LOOKS SIMILAR TO THE GFS...WITH THE FIM
HAVING TIMING MORE IN LINE WITH THE GEM/ECMWF...BUT TAKES THE
SYSTEM WELL SOUTHEAST OF MN/WRN WI. GIVEN ALL THE SPREAD IN
TIMING...MODEL BLEND USED IN THE EXTENDED PORTION OF THIS
FORECAST WOUND UP PLASTERING CHANCE POPS FROM SUNDAY NIGHT THROUGH
TUESDAY. THIS SECOND SYSTEM DOES LOOK SOMEWHAT SIMILAR TO WHAT THE
FIRST STORM WILL BE LIKE...WITH AN OCCLUDED AND FILLING IN LOW
MOVING NORTH OUT OF THE SOUTHERN PLAINS...RESULTING IN HIGHEST
PRECIP AMOUNTS SOUTH OF THE AREA. ONE DIFFERENCE THOUGH BETWEEN
NEXT WEEKS SYSTEM AND THIS WEEKS IS THAT TEMPS WILL BE RUNNING 5
TO 10 DEGREES WARMER NEXT WEEK...THOUGH SHOULD STILL BE JUST COLD
ENOUGH IN THE EAST TO KEEP THINGS AS ALL SNOW.
&&
.AVIATION.../12Z TAF ISSUANCE/
SQUEEZE PLAY FOR THE LOW CLOUDS TODAY...WITH MVFR/IFR CLOUDS
LIFTING NORTHEAST FROM KS/NE...AND STRATUS OOZING SOUTHWEST FROM
LAKE SUPERIOR AND THE UP OF MI. EXPECT THE SOUTHERN BATCH TO
SPREAD FROM SOUTHERN MN TO REACH KRWF-KAXN-KSTC BETWEEN 03Z AND 09Z
FRIDAY...WITH EASTERN SITES /KEAU-KRNH-KMSP/ LIKELY SEEING LOW
CLOUDS ARRIVE EARLIER THIS AFTERNOON. BASED UPON CURRENT SATELLITE
IMAGERY AND HRRR/RAP MODELS...HAVE INTRODUCED A SCT-BKN MVFR CLOUD
LEVEL BETWEEN 17Z AND 20Z AT KEAU-KRNH-KMSP...BECOMING OVERCAST
BETWEEN 21Z THURSDAY AND 00Z FRIDAY. SNOW IS EXPECTED TO BLOSSOM
OVER THE AREA AFTER 05Z FRIDAY...WITH IFR VSBYS AND MVFR CIGS BECOMING
COMMON THROUGH FRIDAY MORNING. WINDS FROM 050-090 DEGREES WILL
PREVAIL...MAINLY FROM 5 TO 10 KTS.
KMSP...
SCT CLOUDS AROUND 2500 FT MAY MOVE INTO THE AIRPORT FROM THE
NORTHEAST THIS AFTERNOON. PER HRRR AND RAP SOLUTIONS...INTRODUCED
A 21Z SCT MVFR CLOUD GROUP...WITH OVC CIGS ARRIVING AROUND 00Z.
STILL EXPECT SNOW TO HOLD OFF UNTIL AFTER 05Z...AS WE/LL STILL BE
WAITING ON THE FORCING/DYNAMICS TO ARRIVE FROM THE SOUTHWEST.
THE TIME FRAME FOR THE WORST CONDITIONS STILL LOOKS TO BE BETWEEN 08Z
AND 12Z...WHEN VSBYS BETWEEN 1/2SM AND 1 SM ARE EXPECTED. WINDS
BETWEEN 080-090 WILL PREVAIL TODAY...WITH 050-070 FOR TONIGHT.
SPEEDS BETWEEN 6 KTS AND 10 KTS ARE EXPECTED THROUGH THE PERIOD.
/OUTLOOK FOR KMSP/
FRI NIGHT...IFR CIGS AND VSBY EXPECTED...WITH
-SN LIKELY. NE WIND 5-15 KT...BECOMING NW LATE.
SAT...MVFR CIGS WITH -SN IN THE MORNING. W WIND 5 KT.
SUN...VFR CIGS EARLY...MVFR CIGS LATE. CHANCE -SN LATE. SE WINDS
BECOMING NE 5 KT.
MON...MVFR CIGS WITH CHANCE -SN. NE WINDS 5 TO 10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 PM CST
FRIDAY FOR BLUE EARTH-BROWN-CARVER-DAKOTA-FARIBAULT-
FREEBORN-GOODHUE-HENNEPIN-LE SUEUR-MARTIN-MCLEOD-NICOLLET-
REDWOOD-RENVILLE-RICE-SCOTT-SIBLEY-STEELE-WASECA-WATONWAN-
WRIGHT.
WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 6 PM CST FRIDAY
FOR ANOKA-CHISAGO-RAMSEY-WASHINGTON.
WI...WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 6 PM CST FRIDAY
FOR BARRON-CHIPPEWA-DUNN-EAU CLAIRE-PEPIN-PIERCE-POLK-RUSK-
ST. CROIX.
&&
$$
MPG/LS
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1131 AM CST Thu Feb 21 2013
...UPDATED AVIATION DISCUSSION...
.DISCUSSION...
Intense winter storm is taking direct aim on the forecast area this
morning. Overnight model runs...including the near-term RAP and
HRRR models...now indicate a broad swath of 1"+ liquid-equivalent
precipitation totals overspreading most of the forecast area with the
heaviest axis centered very close to Kansas City. How these precip
totals translate into snow and sleet amounts is still somewhat of a
question mark given the presence of warm air in the 800-700 hPa layer
and a shallow depth of the max dendritic growth region. Seems most
methods are giving snow to liquid ratios on the order of 8:1 to 10:1
near I-70...and around 10:1 to 12:1 north of Highway 36. Applying
these ratios to expected precip totals now results in a broad swath
of 8 to 12 inch snows forecast for most of the forecast
area...generally along and north of a Paola...Marshall...Moberly
line. These areas are unlikely to see much if any sleet
contamination and could see some totals approach or exceed February
records (see climate section below). Still expect sleet to fall across
areas south of this line, and there could be a good deal of it.
Exactly how much sleet falls across these areas will have huge
impacts on snow amounts, which could be as low as 3 or 4 inches if
sleet lasts several hours...to as much as 8 to 10 inches if sleet is
only brief. Freezing rain still appears a possibility for the
Clinton/Sedalia/Boonville areas but any icing should be limited to a
tenth of an inch or less.
Looking upstream, synoptic and mesoscale ascent has become quite
strong and is coupled throughout a large depth of the atmosphere.
Combine this with strong moisture advection from the south, the
result has been an expanding area of heavy precipitation over
northern OK and southern KS with several bands of convection feeding
into it. In fact, lightning profilers have lit up vividly down there,
even in the stratiform precipitation over KS, suggestive of quite a
bit of slantwise and even upright instability. This instability will
spread into ern KS/wrn MO through the morning and could easily
result in occasional thunder and snowfall rates of 2" to 3" per hour.
Heaviest precipitation band will spread into northern MO through the
afternoon and taper off across the KC area by 21Z or so. However,
broad synoptic scale and weak deformation forcing will continue well
into the evening and overnight as the upper low moves overhead. This
could result in an extra 2" to 5" of snow from late afternoon into
the early morning hours particularly north of the Missouri River.
Hawblitzel
Friday and Saturday...
As the system departs, a few lingering snow showers may be possible
across far northeast Missouri, but little to no additional snow
accumulation is expected. Temperatures will have difficulty rising
much on Friday with widespread snow cover and colder air advecting
into the region, so have kept high temperatures only a few degrees
warmer than Thursday night lows. Frigid temperatures are possible
Friday night as surface high pressure drifts over western Missouri,
combining the residual snow cover with light winds and clear skies.
Warmer air will begin to build into the region on Saturday as the
upper low departs, but reaching highs much above freezing will be
difficult, especially without strong return flow at low levels.
Sunday and Monday...
Another deep trough axis will swing through the four corners region
on Sunday, bringing a deepening surface low into the southern High
Plains by early Monday. This system is currently projected to lift
northeast into the region on Monday afternoon, taking a somewhat
similar track to the current system; however, there is still a good
deal of uncertainty in this forecast. Moisture may be a bit more
limited with a smaller window of time to draw from the Gulf, and
this more southern track is a very recent trend with the 00z models,
so for now have kept probabilities relatively low and maintained a
rain or snow precipitation type to cover several possible scenarios.
Tuesday through Thursday...
Quieter conditions should prevail for the remainder of next week as
a more persistent ridge builds over the west. A few snow showers may
be possible Tuesday night into early Wednesday as a weak clipper
dives in behind the departing upper low, but any snowfall that does
occur should be fairly light, and the probability of measurable snow
is low. Temperatures will remain below normal as a result of cold
air wrapping behind the upper low and additional cold air dropping
southeast with the clipper, but should eventually recover when the
ridge over the Rockies begins to shift east.
Laflin
&&
.CLIMATE...
The last time Kansas City officially measured 12" of snow was
January 18-19 in 1962 (14.0"). The most recent snowfall greater than
10" was February 24-25 in 1993 (11.1").
Top 10 snowfalls for Kansas City
1. 24.2"...Mar 22-24 1912
2. 15.8"...Feb 11-12 1894
3. 14.6"...Jan 20-21 1958
4. 14.0"...Jan 18-19 1962
5. 13.8"...Mar 14-15 1960
6. 13.7"...Jan 8-9 1930
7. 13.0"...Feb 27-28 1900
8. 12.3"...Mar 29-31 1926
9. 12.2"...Dec 23-24 1918
10. 11.9"...Mar 3-5 1915
Top 5 daily February snowfalls for Kansas City
1. 11.8"...27th 1900
2. 10.5"...4th 1915
3. 8.7"...23rd 1990
4. 8.6"...2nd 1960
5. 8.0"...15th 1960
&&
.AVIATION...
For the 18Z TAFs...Heavy snow will tapper off to light snow this
afternoon as dry air aloft works across the terminals from southwest
to northeast. This may result in a brief period of improved
conditions, going from LIFR to MVFR, but conditions will come back
down into the IFR quickly so have left this out of the TAF.
Otherwise, precipitation type might convert to, or mix with, freezing
drizzle. Light snow is expected to persist through the afternoon and
evening hours with additional accumulations.
Cutter
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...WINTER STORM WARNING until Midnight CST tonight FOR MOZ028>030-
037>040-043>046-053-054.
WINTER STORM WARNING until 6 AM CST Friday FOR MOZ001>008-
011>017-020>025-031>033.
KS...WINTER STORM WARNING until Midnight CST tonight FOR KSZ057-060-
103>105.
WINTER STORM WARNING until 6 AM CST Friday FOR KSZ025-102.
&&
$$
WFO EAX
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1037 AM CST Thu Feb 21 2013
.UPDATE...
/1036 AM CST Thu Feb 21 2013/
...Shifting heaviest snow band a bit farther south...
Morning upper air sounding from Springfield showed a unstable
sounding, and sure enough that instability worked north feeding
moisture across the southern reaches of the forecast area. This helped
fuel thunder-snow that has reached as far north as North Kansas City
this morning. Radar trends and satellite imagery are pointing at the
heaviest snow band setting up across the southern half of the
forecast area this morning, shifting to the northeast through the
afternoon hours. Deformation zone snow is developing from northwest
Missouri back into south central Kansas, and will likely be what
brings significant snow accumulations to far northwest Missouri --this
afternoon and this evening--. South of a St Joseph to Kirksville
line...snowfall totals have been bumped up with the heaviest snow
expected to persist through the early to mid afternoon hours. Totals
of greater than 12 inches will be possible as far south as Highway
50. Dry slot is just shy of nosing into the southwest corner of the
forecast area, with reports of precipitation type beginning to
transit from snow and sleet to freezing drizzle. The Threat of
freezing rain continue to look very minimal, but will persist across
areas from east central Kansas into central Missouri through the mid-
afternoon hours.
Cutter
&&
.DISCUSSION...
Intense winter storm is taking direct aim on the forecast area this
morning. Overnight model runs...including the near-term RAP and
HRRR models...now indicate a broad swath of 1"+ liquid-equivalent
precipitation totals overspreading most of the forecast area with the
heaviest axis centered very close to Kansas City. How these precip
totals translate into snow and sleet amounts is still somewhat of a
question mark given the presence of warm air in the 800-700 hPa layer
and a shallow depth of the max dendritic growth region. Seems most
methods are giving snow to liquid ratios on the order of 8:1 to 10:1
near I-70...and around 10:1 to 12:1 north of Highway 36. Applying
these ratios to expected precip totals now results in a broad swath
of 8 to 12 inch snows forecast for most of the forecast
area...generally along and north of a Paola...Marshall...Moberly
line. These areas are unlikely to see much if any sleet
contamination and could see some totals approach or exceed February
records (see climate section below). Still expect sleet to fall across
areas south of this line, and there could be a good deal of it.
Exactly how much sleet falls across these areas will have huge
impacts on snow amounts, which could be as low as 3 or 4 inches if
sleet lasts several hours...to as much as 8 to 10 inches if sleet is
only brief. Freezing rain still appears a possibility for the
Clinton/Sedalia/Boonville areas but any icing should be limited to a
tenth of an inch or less.
Looking upstream, synoptic and mesoscale ascent has become quite
strong and is coupled throughout a large depth of the atmosphere.
Combine this with strong moisture advection from the south, the
result has been an expanding area of heavy precipitation over
northern OK and southern KS with several bands of convection feeding
into it. In fact, lightning profilers have lit up vividly down there,
even in the stratiform precipitation over KS, suggestive of quite a
bit of slantwise and even upright instability. This instability will
spread into ern KS/wrn MO through the morning and could easily
result in occasional thunder and snowfall rates of 2" to 3" per hour.
Heaviest precipitation band will spread into northern MO through the
afternoon and taper off across the KC area by 21Z or so. However,
broad synoptic scale and weak deformation forcing will continue well
into the evening and overnight as the upper low moves overhead. This
could result in an extra 2" to 5" of snow from late afternoon into
the early morning hours particularly north of the Missouri River.
Hawblitzel
Friday and Saturday...
As the system departs, a few lingering snow showers may be possible
across far northeast Missouri, but little to no additional snow
accumulation is expected. Temperatures will have difficulty rising
much on Friday with widespread snow cover and colder air advecting
into the region, so have kept high temperatures only a few degrees
warmer than Thursday night lows. Frigid temperatures are possible
Friday night as surface high pressure drifts over western Missouri,
combining the residual snow cover with light winds and clear skies.
Warmer air will begin to build into the region on Saturday as the
upper low departs, but reaching highs much above freezing will be
difficult, especially without strong return flow at low levels.
Sunday and Monday...
Another deep trough axis will swing through the four corners region
on Sunday, bringing a deepening surface low into the southern High
Plains by early Monday. This system is currently projected to lift
northeast into the region on Monday afternoon, taking a somewhat
similar track to the current system; however, there is still a good
deal of uncertainty in this forecast. Moisture may be a bit more
limited with a smaller window of time to draw from the Gulf, and
this more southern track is a very recent trend with the 00z models,
so for now have kept probabilities relatively low and maintained a
rain or snow precipitation type to cover several possible scenarios.
Tuesday through Thursday...
Quieter conditions should prevail for the remainder of next week as
a more persistent ridge builds over the west. A few snow showers may
be possible Tuesday night into early Wednesday as a weak clipper
dives in behind the departing upper low, but any snowfall that does
occur should be fairly light, and the probability of measurable snow
is low. Temperatures will remain below normal as a result of cold
air wrapping behind the upper low and additional cold air dropping
southeast with the clipper, but should eventually recover when the
ridge over the Rockies begins to shift east.
Laflin
&&
.CLIMATE...
The last time Kansas City officially measured 12" of snow was
January 18-19 in 1962 (14.0"). The most recent snowfall greater than
10" was February 24-25 in 1993 (11.1").
Top 10 snowfalls for Kansas City
1. 24.2"...Mar 22-24 1912
2. 15.8"...Feb 11-12 1894
3. 14.6"...Jan 20-21 1958
4. 14.0"...Jan 18-19 1962
5. 13.8"...Mar 14-15 1960
6. 13.7"...Jan 8-9 1930
7. 13.0"...Feb 27-28 1900
8. 12.3"...Mar 29-31 1926
9. 12.2"...Dec 23-24 1918
10. 11.9"...Mar 3-5 1915
Top 5 daily February snowfalls for Kansas City
1. 11.8"...27th 1900
2. 10.5"...4th 1915
3. 8.7"...23rd 1990
4. 8.6"...2nd 1960
5. 8.0"...15th 1960
&&
.AVIATION...
For the 12Z TAFs...major winter storm will impact all terminals for
much of the day with very heavy snow rates of 1 to 2 inches per hour,
possibly more. Occasional lightning is also possible. This activity
is right on the doorstep, so will go ahead and introduce heavy snow
to the KC and STJ terminals right at the onset of the TAF period. The
heavy nature of the snow is likely to bring every airport below
operational minimums at times. Heaviest snow will gradually taper
off across KC/STJ by mid afternoon, and across central and northeast
MO late afternoon. However, additional light snow through the evening
could produce additional light accumulations and prolonged IFR
conditions through the night.
Hawblitzel
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...WINTER STORM WARNING until Midnight CST tonight FOR MOZ028>030-
037>040-043>046-053-054.
WINTER STORM WARNING until 6 AM CST Friday FOR MOZ001>008-
011>017-020>025-031>033.
KS...WINTER STORM WARNING until Midnight CST tonight FOR KSZ057-060-
103>105.
WINTER STORM WARNING until 6 AM CST Friday FOR KSZ025-102.
&&
$$
WFO EAX
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
530 AM CST Thu Feb 21 2013
...UPDATED AVIATION DISCUSSION...
.DISCUSSION...
Intense winter storm is taking direct aim on the forecast area this
morning. Overnight model runs...including the near-term RAP and
HRRR models...now indicate a broad swath of 1"+ liquid-equivalent
precipitation totals overspreading most of the forecast area with the
heaviest axis centered very close to Kansas City. How these precip
totals translate into snow and sleet amounts is still somewhat of a
question mark given the presence of warm air in the 800-700 hPa layer
and a shallow depth of the max dendritic growth region. Seems most
methods are giving snow to liquid ratios on the order of 8:1 to 10:1
near I-70...and around 10:1 to 12:1 north of Highway 36. Applying
these ratios to expected precip totals now results in a broad swath
of 8 to 12 inch snows forecast for most of the forecast
area...generally along and north of a Paola...Marshall...Moberly
line. These areas are unlikely to see much if any sleet
contamination and could see some totals approach or exceed February
records (see climate section below). Still expect sleet to fall across
areas south of this line, and there could be a good deal of it.
Exactly how much sleet falls across these areas will have huge
impacts on snow amounts, which could be as low as 3 or 4 inches if
sleet lasts several hours...to as much as 8 to 10 inches if sleet is
only brief. Freezing rain still appears a possibility for the
Clinton/Sedalia/Boonville areas but any icing should be limited to a
tenth of an inch or less.
Looking upstream, synoptic and mesoscale ascent has become quite
strong and is coupled throughout a large depth of the atmosphere.
Combine this with strong moisture advection from the south, the
result has been an expanding area of heavy precipitation over
northern OK and southern KS with several bands of convection feeding
into it. In fact, lightning profilers have lit up vividly down there,
even in the stratiform precipitation over KS, suggestive of quite a
bit of slantwise and even upright instability. This instability will
spread into ern KS/wrn MO through the morning and could easily
result in occasional thunder and snowfall rates of 2" to 3" per hour.
Heaviest precipitation band will spread into northern MO through the
afternoon and taper off across the KC area by 21Z or so. However,
broad synoptic scale and weak deformation forcing will continue well
into the evening and overnight as the upper low moves overhead. This
could result in an extra 2" to 5" of snow from late afternoon into
the early morning hours particularly north of the Missouri River.
Hawblitzel
Friday and Saturday...
As the system departs, a few lingering snow showers may be possible
across far northeast Missouri, but little to no additional snow
accumulation is expected. Temperatures will have difficulty rising
much on Friday with widespread snow cover and colder air advecting
into the region, so have kept high temperatures only a few degrees
warmer than Thursday night lows. Frigid temperatures are possible
Friday night as surface high pressure drifts over western Missouri,
combining the residual snow cover with light winds and clear skies.
Warmer air will begin to build into the region on Saturday as the
upper low departs, but reaching highs much above freezing will be
difficult, especially without strong return flow at low levels.
Sunday and Monday...
Another deep trough axis will swing through the four corners region
on Sunday, bringing a deepening surface low into the southern High
Plains by early Monday. This system is currently projected to lift
northeast into the region on Monday afternoon, taking a somewhat
similar track to the current system; however, there is still a good
deal of uncertainty in this forecast. Moisture may be a bit more
limited with a smaller window of time to draw from the Gulf, and
this more southern track is a very recent trend with the 00z models,
so for now have kept probabilities relatively low and maintained a
rain or snow precipitation type to cover several possible scenarios.
Tuesday through Thursday...
Quieter conditions should prevail for the remainder of next week as
a more persistent ridge builds over the west. A few snow showers may
be possible Tuesday night into early Wednesday as a weak clipper
dives in behind the departing upper low, but any snowfall that does
occur should be fairly light, and the probability of measurable snow
is low. Temperatures will remain below normal as a result of cold
air wrapping behind the upper low and additional cold air dropping
southeast with the clipper, but should eventually recover when the
ridge over the Rockies begins to shift east.
Laflin
&&
.CLIMATE...
The last time Kansas City officially measured 12" of snow was
January 18-19 in 1962 (14.0"). The most recent snowfall greater than
10" was February 24-25 in 1993 (11.1").
Top 10 snowfalls for Kansas City
1. 24.2"...Mar 22-24 1912
2. 15.8"...Feb 11-12 1894
3. 14.6"...Jan 20-21 1958
4. 14.0"...Jan 18-19 1962
5. 13.8"...Mar 14-15 1960
6. 13.7"...Jan 8-9 1930
7. 13.0"...Feb 27-28 1900
8. 12.3"...Mar 29-31 1926
9. 12.2"...Dec 23-24 1918
10. 11.9"...Mar 3-5 1915
Top 5 daily February snowfalls for Kansas City
1. 11.8"...27th 1900
2. 10.5"...4th 1915
3. 8.7"...23rd 1990
4. 8.6"...2nd 1960
5. 8.0"...15th 1960
&&
.AVIATION...
For the 12Z TAFs...major winter storm will impact all terminals for
much of the day with very heavy snow rates of 1 to 2 inches per hour,
possibly more. Occasional lightning is also possible. This activity
is right on the doorstep, so will go ahead and introduce heavy snow
to the KC and STJ terminals right at the onset of the TAF period. The
heavy nature of the snow is likely to bring every airport below
operational minimums at times. Heaviest snow will gradually taper
off across KC/STJ by mid afternoon, and across central and northeast
MO late afternoon. However, additional light snow through the evening
could produce additional light accumulations and prolonged IFR
conditions through the night.
Hawblitzel
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...WINTER STORM WARNING until Midnight CST tonight FOR MOZ039-040-
045-046.
WINTER STORM WARNING until Midnight CST tonight FOR MOZ028>030-
037-038-043-044-053-054.
WINTER STORM WARNING until 6 AM CST Friday FOR MOZ001>004-
011>013-020-021.
WINTER STORM WARNING until 6 AM CST Friday FOR MOZ005>008-
014>017-022>025-031>033.
KS...WINTER STORM WARNING until Midnight CST tonight FOR KSZ057-060-
103>105.
WINTER STORM WARNING until 6 AM CST Friday FOR KSZ025-102.
&&
$$
WFO EAX
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
353 AM CST Thu Feb 21 2013
.DISCUSSION...
Intense winter storm is taking direct aim on the forecast area this
morning. Overnight model runs...including the near-term RAP and
HRRR models...now indicate a broad swath of 1"+ liquid-equivalent
precipitation totals overspreading most of the forecast area with the
heaviest axis centered very close to Kansas City. How these precip
totals translate into snow and sleet amounts is still somewhat of a
question mark given the presence of warm air in the 800-700 hPa layer
and a shallow depth of the max dendritic growth region. Seems most
methods are giving snow to liquid ratios on the order of 8:1 to 10:1
near I-70...and around 10:1 to 12:1 north of Highway 36. Applying
these ratios to expected precip totals now results in a broad swath
of 8 to 12 inch snows forecast for most of the forecast
area...generally along and north of a Paola...Marshall...Moberly
line. These areas are unlikely to see much if any sleet
contamination and could see some totals approach or exceed February
records (see climate section below). Still expect sleet to fall across
areas south of this line, and there could be a good deal of it.
Exactly how much sleet falls across these areas will have huge
impacts on snow amounts, which could be as low as 3 or 4 inches if
sleet lasts several hours...to as much as 8 to 10 inches if sleet is
only brief. Freezing rain still appears a possibility for the
Clinton/Sedalia/Boonville areas but any icing should be limited to a
tenth of an inch or less.
Looking upstream, synoptic and mesoscale ascent has become quite
strong and is coupled throughout a large depth of the atmosphere.
Combine this with strong moisture advection from the south, the
result has been an expanding area of heavy precipitation over
northern OK and southern KS with several bands of convection feeding
into it. In fact, lightning profilers have lit up vividly down there,
even in the stratiform precipitation over KS, suggestive of quite a
bit of slantwise and even upright instability. This instability will
spread into ern KS/wrn MO through the morning and could easily
result in occasional thunder and snowfall rates of 2" to 3" per hour.
Heaviest precipitation band will spread into northern MO through the
afternoon and taper off across the KC area by 21Z or so. However,
broad synoptic scale and weak deformation forcing will continue well
into the evening and overnight as the upper low moves overhead. This
could result in an extra 2" to 5" of snow from late afternoon into
the early morning hours particularly north of the Missouri River.
Hawblitzel
Friday and Saturday...
As the system departs, a few lingering snow showers may be possible
across far northeast Missouri, but little to no additional snow
accumulation is expected. Temperatures will have difficulty rising
much on Friday with widespread snow cover and colder air advecting
into the region, so have kept high temperatures only a few degrees
warmer than Thursday night lows. Frigid temperatures are possible
Friday night as surface high pressure drifts over western Missouri,
combining the residual snow cover with light winds and clear skies.
Warmer air will begin to build into the region on Saturday as the
upper low departs, but reaching highs much above freezing will be
difficult, especially without strong return flow at low levels.
Sunday and Monday...
Another deep trough axis will swing through the four corners region
on Sunday, bringing a deepening surface low into the southern High
Plains by early Monday. This system is currently projected to lift
northeast into the region on Monday afternoon, taking a somewhat
similar track to the current system; however, there is still a good
deal of uncertainty in this forecast. Moisture may be a bit more
limited with a smaller window of time to draw from the Gulf, and
this more southern track is a very recent trend with the 00z models,
so for now have kept probabilities relatively low and maintained a
rain or snow precipitation type to cover several possible scenarios.
Tuesday through Thursday...
Quieter conditions should prevail for the remainder of next week as
a more persistent ridge builds over the west. A few snow showers may
be possible Tuesday night into early Wednesday as a weak clipper
dives in behind the departing upper low, but any snowfall that does
occur should be fairly light, and the probability of measurable snow
is low. Temperatures will remain below normal as a result of cold
air wrapping behind the upper low and additional cold air dropping
southeast with the clipper, but should eventually recover when the
ridge over the Rockies begins to shift east.
Laflin
&&
.CLIMATE...
The last time Kansas City officially measured 12" of snow was
January 18-19 in 1962 (14.0"). The most snowfall greater than 10" was
February 24-25 in 1993 (11.1").
Top 10 snowfalls for Kansas City
1. 24.2"...Mar 22-24 1912
2. 15.8"...Feb 11-12 1894
3. 14.6"...Jan 20-21 1958
4. 14.0"...Jan 18-19 1962
5. 13.8"...Mar 14-15 1960
6. 13.7"...Jan 8-9 1930
7. 13.0"...Feb 27-28 1900
8. 12.3"...Mar 29-31 1926
9. 12.2"...Dec 23-24 1918
10. 11.9"...Mar 3-5 1915
Top 5 daily February snowfalls for Kansas City
1. 11.8"...27th 1900
2. 10.5"...4th 1915
3. 8.7"...23rd 1990
4. 8.6"...2nd 1960
5. 8.0"...15th 1960
&&
.AVIATION...
For the 06Z TAFs...Thinks look to be on track for the winter storm
system that will affect the terminals beginning this morning.
Overnight conditions will remain VFR with a cloud deck between
6-7kft. Light returns showing up on radar will remain as virga as
the air in the lower 6kft will be very dry. By 14Z-15Z this dry air
will be overcome and cigs will quick drop into the MVFR category
with vsbys dropping 5SM with the onset of light snow. There will be
a period of moderate to occasionally heavy snow at the terminals
between 17Z-21Z at which point snow rates could be as high 2-3"
inches per hour thus making it difficult for snow removal on
runways. The heavy snow will also be accompanied by IFR and
occasional VLIFR cigs/vis with even the potential for thundersnow
which may be added to the TAF forecast as we get closer to the
event. Moderate snow is then expected to continue with IFR cigs/vis
through 23Z. Snow should begin to taper off becoming light by 23Z
however IFR cigs with vsbys improving to 1SM will continue through
the end of the TAF period. Winds overnight will be between 10-15kts
but will pick up tomorrow morning as the pressure gradient tightens
across the area. Winds tomorrow will be between 15-20kts with gusts
to 25-30kts however blowing snow is not expected to be a concern due
to the heavy nature of the snow. Winds will weaken somewhat by
tomorrow evening but still remain between 10-15kts with gusts to
25kts while backing to the east-northeast.
73
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...WINTER STORM WARNING until Midnight CST tonight FOR MOZ039-040-
045-046.
WINTER STORM WARNING until Midnight CST tonight FOR MOZ028>030-
037-038-043-044-053-054.
WINTER STORM WARNING until 6 AM CST Friday FOR MOZ001>004-
011>013-020-021.
WINTER STORM WARNING until 6 AM CST Friday FOR MOZ005>008-
014>017-022>025-031>033.
KS...WINTER STORM WARNING until Midnight CST tonight FOR KSZ057-060-
103>105.
WINTER STORM WARNING until 6 AM CST Friday FOR KSZ025-102.
&&
$$
WFO EAX
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1011 PM CST WED FEB 20 2013
.UPDATE...
ISSUED AT 928 PM CST WED FEB 20 2013
NOT A WHOLE LOT OF CHANGES TO THE FORECAST FOR TONIGHT ASIDE FROM
INCREASING SNOWFALL AMOUNTS IN OUR SOUTHWEST ZONES WHERE A 9 INCH
AMOUNT HAS BEEN RECEIVED IN PLAINVILLE KS IN ROOKS COUNTY. FARTHER
EAST...THE DRIER AIR HAS BEEN SLOW TO OVERCOME AND HAVE LOWERED
SNOWFALL AMOUNTS SLIGHTLY FOR OUR EAST/NORTHEAST ZONES. SNOW HAS
BEGUN TO INCREASE IN COVERAGE ACROSS OUR SOUTHWEST CWA AND THE
SNOW WILL SPREAD NORTH OVERNIGHT. OUR EASTERN AREAS COULD STILL
PICK UP AN INCH OR TWO PRIOR TO DAYBREAK...ALTHOUGH THE HIGHER
AMOUNTS WILL STILL BE REALIZED ACROSS SOUTHERN/WESTERN AREAS. THE
00Z RUN OF THE NAM REMAINS CONSISTENT WITH THE UPPER LOW LIFTING
NORTHEAST FM THE TX PANHANDLE THURSDAY MORNING INTO EAST CENTRAL
KS BY 00Z FRIDAY. DEFORMATION SNOWFALL WILL DEVELOP ACROSS KS
EARLY THURSDAY AND SPREAD NORTHWARD AS SYSTEMS LIFTS NORTHEAST
DURING THE DAY. WE ARE STILL LOOKING AT WIDESPREAD HEAVY SNOWFALL
DEVELOPING IN KS THURSDAY MORNING AND SPREADING INTO NEBRASKA BY
THURSDAY AFTN AND CONTINUING INTO THE EVENING. 00Z NAM STORM TOTAL
SNOWFALL REMAINS CONSISTENT WITH PREVIOUS RUNS AND OTHER MODELS
WITH POTENTIAL OF 10 INCHES OR MORE OF SNOW...WITH WELL OVER A
FOOT POSSIBLE ACROSS NC KS INTO SW/SC NEB.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 239 PM CST WED FEB 20 2013
TONIGHT THROUGH EARLY FRIDAY MORNING...FOCUS CONTINUES
TO BE ON THE APPROACHING UPPER LEVEL DISTURBANCE CURRENTLY VISIBLE
IN WATER VAPOR IMAGERY CIRCULATING ACROSS CENTRAL ARIZONA. MOISTURE
AHEAD OF THIS DISTURBANCE HAS BEEN SURGING NORTHWARD FOR MUCH OF THE
DAY TODAY...WITH LIGHT SNOW SLOWLY SPREADING NORTHWARD INTO PORTIONS
OF SOUTH CENTRAL NEBRASKA THE PAST FEW HOURS. EXPECT THIS LIGHT SNOW
TO CONTINUE THROUGH THE EVENING HOURS...AND INTENSIFY SOME
OVERNIGHT. WITH THE OVERALL SLOWER AND MORE SOUTHEASTWARD TRACK OF
THIS SYSTEM...NOW EXPECT THE HEAVIEST SNOWFALL TO DEVELOP IN BANDS
ACROSS NORTH CENTRAL KANSAS DURING THE EARLY MORNING HOURS
THURSDAY...WORKING ITS WAY INTO SOUTH CENTRAL NEBRASKA BY MID
MORNING. THAT SAID...STILL EXPECT SOME SNOWFALL ACCUMULATIONS THIS
AFTERNOON AND EVENING...ESPECIALLY ACROSS THE SOUTHWESTERN SECTIONS
OF THE FORECAST AREA...WITH LIGHT SNOWFALL POSSIBLY NOT WORKING INTO
THE EASTERN FRINGES OF THE LOCAL AREA UNTIL ABOUT MIDNIGHT.
LATEST RAP CONTINUES TO BE THE MAIN OUTLIER HOLDING OFF WIDESPREAD
SNOW UNTIL AROUND DAYBREAK THURSDAY FOR MUCH OF THE EASTERN HALF OF
THE FORECAST AREA...DUE TO ITS DEPICTION OF A MORE SIGNIFICANT DRY
LAYER NEAR THE GROUND IN THE LOW LEVEL EASTERLY FLOW. HOWEVER...WITH
THE NAM/SREF/GFS/EC/WRF ALL DEVELOPING MORE WIDESPREAD PRECIPITATION
BEFORE THEN...MOSTLY DISCOUNTED RAP ANALYSIS...AND KEPT ONSET OF
PRECIPITATION SIMILAR TO THIS MORNINGS FORECAST. OTHERWISE...WHILE
THE OVERALL TIMING OF THE MAIN SYSTEM ACROSS THE DESERT SOUTHWEST
HAS SLOWED DOWN A BIT IN THE 12Z MODELS...IT STILL LOOKS TO BE A
MAJOR WINTER STORM EVENT...AND HAVE ADJUSTED FOR THE SLOWER ANALYSIS
BY EXTENDING THE WINTER STORM WARNING FOR THE NORTH/NORTHEASTERN
HALF OF THE AREA BY 6 HOURS. AND WHILE OVERALL LIQUID EQUIVALENTS
HAVE COME DOWN TO AROUND AN INCH FOR THE TRI CITIES AREA WITH THIS
SYSTEM...RANGING FROM AROUND 0.75 IN THE EC TO AROUND 1.2 IN THE
NAM...INCREASED SNOWFALL RATIOS TO BE SLIGHTLY HIGHER THAN
PREVIOUSLY THOUGHT IN THIS COLD AIRMASS...SO ONLY VERY MINOR TWEAKS
ARE EVIDENT IN THE OVERALL SNOWFALL ACCUMULATIONS.
IN ADDITION TO SNOWFALL...EXPECT BREEZY SOUTHEASTERLY WINDS TO
CONTINUE THROUGH THE EVENING AND OVERNIGHT HOURS...AS THE PRESSURE
GRADIENT BEGINS TO TIGHTEN AHEAD OF THE APPROACHING SURFACE LOW.
WINDS ARE THEN EXPECTED TO EVENTUALLY RELAX AND SHIFT MORE NORTHERLY
ON THE BACKSIDE OF THE SURFACE LOW AS IT CROSSES INTO MISSOURI AND
IOWA BY TOMORROW EVENING. HOWEVER...WITH LOTS OF FAIRLY DRY SNOW AND
BREEZY WINDS...VISIBILITIES ARE EXPECTED TO BE REDUCED IN AREAS OF
BLOWING SNOW THROUGH THE DURATION OF THIS EVENT...NOT IMPROVING TIL
AFTER 00Z...AND KEPT AREAS OF BLOWING SNOW IN THE FORECAST AS A
CONSEQUENCE.
TEMPERATURES THROUGH THIS EVENT ARE EXPECTED TO REMAIN ON THE COLD
SIDE OF CLIMATOLOGY FOR MID FEBRUARY...WITH AFTERNOON HIGHS ON
THURSDAY LIKELY NOT RISING MUCH ABOVE THE MORNING LOWS AS THE CLOUD
COVER AND SNOW WILL PUT A CAP ON HEATING ACROSS THE LOCAL AREA.
TEMPERATURES ARE THEN EXPECTED TO PLUMMET FRIDAY MORNING ON THE
BACKSIDE OF THIS SYSTEM...AS SOME CLEARING ALONG WITH RELAXING WINDS
AND FRESH SNOW COVER SHOULD ALLOW FOR GOOD RADIATIONAL COOLING BY
EARLY FRIDAY MORNING.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 239 PM CST WED FEB 20 2013
PATTERN: THIS IS A STORMY PATTERN AND EXCITING IF YOU/RE A WINTER WX
FAN. WE ARE LIKELY TO SEE WINTERS FURY CONTINUE FULL BORE THRU THE
END OF THE MONTH. THIS MEANS AT LEAST ONE MORE SNOW/WIND STORM AND
COLDER THAN NORMAL DAYTIME TEMPS...WITH SEVERAL DAYS OF MUCH BELOW
NORMAL /ANYTHING 33F OR BELOW/. THE -PNA/-NAO IS DICTATING THE
LONG-WAVE PATTERN WHICH FEATURES A STORMY WRN USA TROF AND
INCREASING DOWNSTREAM BLOCKING OVER ERN N AMERICA.
FOR THOSE NOT EXCITED ABOUT WINTER WX...THE PNA WILL REACH ITS
LOWEST POINT THIS WEEK AND THEN TURN POSITIVE THE 1ST WEEK OF MAR.
THE ANOMALOUS E PAC RIDGE /+2 STANDARD DEVIATION HGTS/ WILL TAKE A
BIG HIT NEXT MON-TUE FROM A DEEPENING GULF OF AK STORM. THIS WILL
INITIATE THE RETROGRESSION AND REPOSITION THE LONG-WAVE TROF FURTHER
W...INDUCING A RIDGE OVER THE WRN USA NEXT WED.
HAZARDS: THERE IS POTENTIAL FOR ANOTHER WINTER STORM SUN NGT-MON
WITH APPRECIABLE AMOUNTS OF SNOW POSSIBLE.
UPCOMING PCPN OPPORTUNITIES: 2/25.
FRI THE STORM CONTINUES TO EXIT. ANOTHER PIECE OF ENERGY MOVES
THRU SAT...ON THE BACKSIDE OF THE TROF. THE NEXT POTENT TROF DIVES
INTO THE INTERMOUNTAIN W IN THE MEANTIME...AND DEEPENS SUN-MON AS
WAVELENGTH DECREASES. ANOTHER VORT MAX FOLLOWS INTO THE DESERT SW
TUE AND THIS ODDS FAVOR THIS STORM BEING SUPPRESSED FAR TO OUR S.
THE DAILY DETAILS...
CONFIDENCE IS BELOW AVERAGE ON OUR DAYTIME HIGHS THRU THE PERIOD
SINCE MODELS STRUGGLE WITH SUBSTANTIAL SNOW-PACK ON THE GROUND. WE
MAY NOT BE COLD ENOUGH.
FRI: CLEAN-UP AND RECOVERY BUT VERY COLD WITH PLENTY OF CLOUDS. ANY
BREAKS THAT DEVELOP WILL FILL BACK IN UNDER THERMAL TROF. CANT
COMPLETELY RULE OUT A STRAY AFTN FLURRY. WINDS NOT BAD.
SAT: QUIET INTERLUDE. CONFIDENCE IS AVERAGE. WOULDNT RULE OUT SOME
FLURRIES...BUT LOW-LEVEL MSTR APPEARS LIMITED.
SAT NGT: MAINTAINED CONTINUITY WITH PREVIOUS FCST FOR A SLGT CHANCE
OF FRZG DRZL...BUT WITH LOW CONFIDENCE. INCREASING LOW-LEVEL MSTR
OVER A COLD SNOW PACK COULD RESULT IN STRATUS. DID REMOVE FLURRIES
FROM THE FCST. LOW-LEVEL THERMAL PROFILES MAY NOT BE COLD ENOUGH
FOR SNOW GRAINS.
SUN: BACKED DOWN POPS TO SLGT CHANCE.
SUN NGT-MON: THIS STORM COULD BE TROUBLE. COORDINATED WITH HPC AT
1530Z. BELIEVE THIS STORM TAKES A VERY SIMILAR TRACK TO THE CURRENT
STORM. THE DIFF IS THIS STORM IS WE/RE GETTING A SIGNAL THAT IT
LINGERS OR STALLS OVER ERN KS DURING THE DAYLIGHT HRS MON...BEFORE
SLOWLY HEADING TOWARD THE GREAT LAKES MON NGT-TUE.
ACCUMULATING/PLOWABLE SNOW REQUIRING WATCHES/WARNINGS/ADVISORIES
APPEARS LIKELY BASED ON TRENDS IN THE LAST 72 HRS. BUT THIS DOES
NOT NECESSARILY MEAN FOR OUR ENTIRE FCST AREA. POPS HAVE BEEN
INCREASED TO 60-70%. THINK WE NEED TO PREPARE FOR THE OPTION OF A
SLOW-MOVING...POSSIBLY LONG-LIVED STORM. THE BLOCKING HIGH
DOWNSTREAM URGES CAUTION.
THIS STORM HAS POTENTIAL TO BE VERY WINDY.
MODELS: 1456Z PMDEPD AND HPC GUIDANCE REVIEWED AND WE ARE IN
AGREEMENT ON A SLOWER SOLUTION PER THE EC/GEM ENSEMBLES. MOST GFS
ENSEMBLE MEMBERS LOOK TOO FAST/PROGRESSIVE AS EARLY AS 12Z/SUN. EVEN
THE HIGHER RES OPERATIONAL GFS RUNS ARE TOWARD THE SLOWER PACK.
TUE: CYCLONIC FLOW GRADUALLY RELEASES BUT STILL EXPECT PLENTY OF
CLOUDS THRU MIDDAY UNDER THERMAL TROF. BEST IMPROVEMENT S AND W OF
TRI-CITIES.
WED: QUIET AND DRY.
NAO/PNA TELECONNECTIONS: THESE REFER TO THE NORTH ATLANTIC
OSCILLATION AND PACIFIC-NORTH AMERICAN OSCILLATION. THESE
OSCILLATIONS DEAL WITH RIDGES/TROFS AND PATTERNS IN THE JET
STREAM. THE VARIOUS CONFIGURATIONS DICTATE WHAT OUR SENSIBLE
WEATHER WILL BE...ABOVE OR BELOW NORMAL TEMPS...AND DRIER OR
WETTER THAN NORMAL.
-PNA: THIS IS A TROF OVER THE WRN USA. COLDER AND STORMIER FOR THE
CNTRL PLAINS.
+PNA: THIS IS A RIDGE OVER THE WRN USA. THIS IS A QUIET AND MILD
PATTERN HERE.
THE NAO IS MOSTLY A PLAYER IN OUR STORM TRACKS HERE ON THE PLAINS.
+NAO: NO BLOCKING IN THE ATMOSPHERE NEAR GREENLAND. AT TIMES...
THIS ALLOWS COLORADO LOWS TO TRACK MORE ACROSS NEB.
-NAO: BLOCKING NEAR GREENLAND. THIS TENDS TO FORCE COLORADO LOWS
TO OUR S...ACROSS KS.
THIS WEBSITE HAS ADDITIONAL INFO...SOME OF WHICH IS TECHNICAL.
CHECK OUT THE MAPS THAT INDICATE INDICATE THE POSITIVE PHASES.
WARM COLORS INDICATE WARMER TEMPS AND DECREASED STORMINESS. COLD
COLORS INDICATE COLDER TEMPS AND INCREASED STORMINESS. FOR THE
NEGATIVE PHASES...JUST REVERSE THE COLORS. THESE TELECONNECTIONS
HAVE THE GREATEST IMPACTS IN THE COOLER MONTHS OF THE YEAR.
WWW.CPC.NCEP.NOAA.GOV/DATA/TELEDOC/TELEINTRO.SHTML (ALL LOWER CASE)
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1005 PM CST WED FEB 20 2013
SNOW WILL CONTINUE TO FALL INTERMITTENTLY THROUGH THE NIGHT WITH
THE HEAVIEST SNOWFALL EXPECTED FROM MIDDAY THURSDAY THROUGH THE
AFTERNOON AND EVENING AS A POTENT WINTER STORM SYSTEM CROSSES THE
CENTRAL PLAINS. STEADY EASTERLY WINDS OVERNIGHT WILL TRANSITION
NORTHEAST AND NORTHERLY THURS AFTN AND EVENING. CIGS AND VSBYS
WILL BE DEPENDENT ON TIMING OF SNOW BANDS WITH LIFR CONDITONS
LIKELY THURS AFTN/EVE.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...WINTER STORM WARNING UNTIL MIDNIGHT CST THURSDAY NIGHT FOR
NEZ039>041-046>049-060>064-072>077-085>087.
WINTER STORM WARNING UNTIL 6 PM CST THURSDAY FOR NEZ082>084.
KS...WINTER STORM WARNING UNTIL 6 PM CST THURSDAY FOR KSZ005>007-
017>019.
&&
$$
UPDATE...FAY
SHORT TERM...ROSSI
LONG TERM...HALBLAUB
AVIATION...FAY
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
457 PM MST FRI FEB 22 2013
.AVIATION...
00Z TAF CYCLE
UPPER DISTURBANCE PASSING OVER NORTH CENTRAL/NORTHEAST NEW MEXICO
BEFORE 23/12Z AND WILL BE ACCOMPANIED BY A COLD FRONT. SCT MAINLY
MVFR CIGS/VBSYS IN SHSN WILL OCCASIONALLY OBSCURE MTS MAINLY
ESPECIALLY ALONG AND NORTH OF INTERSTATE 40. SOME CLEARING
ANTICIPATE AFTER 23/15Z WITH WINDS ALOFT BECOMING WLY AND SFC LEE
TROUGH DEVELOPING AFT 23/18Z.
&&
.PREV DISCUSSION...324 PM MST FRI FEB 22 2013...
ANOTHER WEAK UPPER WAVE SLIDING ACROSS NORTHERN NM IN FAST NNW FLOW
WILL KEEP THE SNOW MACHINE GOING OVER THE HIGH TERRAIN THROUGH EARLY
SATURDAY. LOCAL HI RES WRF...NAM12...AND HRRR SOLUTIONS SHOW MESOSCALE
FEATURES WITHIN THE LARGER SCALE REGIME SLIDING SOUTHWARD OUT OF THE
NORTHERN MTS TONIGHT INTO THE RIO GRANDE VALLEY FROM SANTA FE TO THE
ABQ METRO AREA THIS EVENING. INCREASED POPS ACCORDINGLY AND PLACED A
DUSTING TO 1 INCH FOR THESE AREAS. FOR THE HIGH TERRAIN THERE HAS
BEEN AN EBB AND FLOW OF LIGHT TO MODERATE SNOW AND SNOW SHOWERS SINCE
THURSDAY MORNING WITH 1-4 INCHES OF SNOW EACH 12HR PERIOD ADDING UP
TO SOME MODEST ACCUMULATIONS. TONIGHT WILL FEATURE ANOTHER 1-4 INCHES
ABOVE 7500 FEET. A DISTINCT BREAK WILL TAKE SHAPE FOR THE ENTIRE
AREA SATURDAY BEHIND TONIGHTS UPPER WAVE.
A HIGHER IMPACT STORM WILL MOVE OVER NORTHERN NM SATURDAY NIGHT AND
SUNDAY. THIS SYSTEM WILL BRING WITH IT A STRONG PACIFIC COLD FRONT
AND ANOTHER ROUND OF WIND AND SNOW. THE NORTHERN MTS WILL SEE AN
ADDITIONAL SEVERAL INCHES OF SNOW BUT WITH MORE WIND AND COLDER
TEMPS THAN THE PAST 36 HRS SO SOME WINTER HIGHLIGHTS ARE EXPECTED.
THE NE PLAINS WILL BE IN THE ACTION AS WELL WITH A TROWAL FEATURE
SLIDING OVER THE AREA AS THE STORM SYSTEM DEEPENS OVER THE PLAINS
STATES. TEMPS WILL DIVE BACK 10 TO 20F BLW NORMAL ONCE AGAIN.
CONFIDENCE IS NOT HIGH ENOUGH FOR A WINTER STORM WATCH AT THIS
TIME BUT IF MODEL TRENDS CONTINUE TO STRENGTHEN THAT COULD CHANGE.
COLD TEMPS WILL CONTINUE INTO MONDAY AND TUESDAY WITH BREEZY TO
LOCALLY WINDY CONDITIONS EXPECTED. BY LATE TUESDAY GUIDANCE SHOWS
ANOTHER WAVE SLIDING SE OVER THE AREA WITH MORE SNOWFALL ACCUMS
FOR THE NORTHERN HIGH TERRAIN. ANOTHER BREAK IS ON TAP WEDNESDAY
BEFORE ANOTHER FAST MOVING SHEARED WAVE SLIDES OVER THURSDAY. BY
THE END OF THE WEEK GUIDANCE FINALLY STOPS THE WAVE TRAIN AND
SLOWLY PUSHES A RIDGE TOWARD THE AREA WITH SLIGHTLY WARMER TEMPS.
GUYER
&&
.FIRE WEATHER...
AN UPPER LEVEL TROUGH WILL MOVE RAPIDLY TO THE EAST ACROSS NORTHERN
NM TONIGHT PRODUCING LIGHT TO MODERATE SNOWFALL IN THE HIGHER
TERRAIN AND ISOLATED AREAS OF LIGHT SNOW IN THE LOWER ELEVATIONS.
MOIST NORTHWEST TO WEST FLOW ACROSS NORTHERN AND CENTRAL NM TONIGHT
WILL KEEP RELATIVE HUMIDITIES ABOVE NORMAL THROUGH SATURDAY MORNING.
INCREASING 700 MB WINDS AND THE FORMATION OF WEAK SURFACE LOW
PRESSURE IN EASTERN NM ON SATURDAY WILL RESULT IN WEST WIND GUSTS UP
TO 35 MPH EAST OF THE CENTRAL MOUNTAINS ALONG AND SOUTH OF I-40.
MINIMUM RELATIVE HUMIDITY IN THESE AREAS WILL GENERALLY BE IN THE
17-25 PERCENT RANGE...SO THE RISK OF CRITICAL FIRE WEATHER
CONDITIONS DEVELOPING SATURDAY AFTERNOON APPEARS LOW. VENTILATION
SATURDAY WILL BE FAIR TO GOOD WEST OF THE CONTINENTAL DIVIDE AND
GOOD TO VERY GOOD EAST OF THE DIVIDE.
A SIGNIFICANTLY STRONGER AND COLDER UPPER LEVEL LOW WILL MOVE FROM
THE EASTERN GREAT BASIN ACROSS NORTHERN AND CENTRAL NM SATURDAY
NIGHT THROUGH SUNDAY AND THEN EXIT ACROSS NORTHEASTERN NM SUNDAY
NIGHT. THE TRACK OF THIS SYSTEM HAS BEEN PROGRESSIVELY FURTHER TO
THE SOUTH ON MODEL RUNS OVER THE PAST 48 HOURS. THIS TRACK WILL
GENERATE THE STRONGEST WINDS ACROSS SOUTHERN NM ON SUNDAY. THE
DRIEST LOW LEVEL AIR AND STRONGEST WINDS WILL LIKELY STAY TO THE
SOUTH OF THE FIRE DISTRICT. WINDS WILL STILL BE MODERATE SUNDAY WITH
GUSTS BETWEEN 30 TO 35 MPH ACROSS CENTRAL NM...ESPECIALLY SOUTH OF
I-40. MOISTURE ACCOMPANYING THIS UPPER LEVEL TROUGH WILL KEEP
DAYTIME RELATIVE HUMIDITY VALUES NEAR OR ABOVE 20 PERCENT...SO
CRITICAL FIRE WEATHER CONDITIONS WILL BE UNLIKELY. SUSTAINED
NORTHWEST WINDS SUNDAY WILL RANGE FROM 10 TO 25 MPH....RESULTING IN
VERY GOOD TO EXCELLENT VENTILATION. AS THE UPPER LOW MOVES EASTWARD
ACROSS WESTERN OK SUNDAY NIGHT...WRAP-AROUND MOISTURE WILL KEEP
RELATIVE HUMIDITY HIGH ACROSS EASTERN NM....WHILE DECREASING WIND
SPEEDS AND RESIDUAL LOW LEVEL MOISTURE ACROSS CENTRAL AND WESTERN NM
WILL ALLOW FOR STRONG RELATIVE HUMIDITY RECOVERIES SUNDAY NIGHT
THROUGH MONDAY MORNING.
HIGH PRESSURE WILL BUILD ACROSS NM FROM THE WEST ON MONDAY WITH
LIGHTER WINDS AND DRIER LOW LEVEL AIR MOVING INTO THE REGION.
AFTERNOON WINDS IN THE EASTERN PLAINS WILL CREATE FAIR TO GOOD
VENTILATION...BUT LIGHTER WINDS ACROSS THE REMAINDER OF NM WILL
CREATE ONLY POOR TO FAIR VENTILATION.
ANOTHER UPPER LEVEL TROUGH MAY AFFECT NORTHERN AND CENTRAL NM ON
TUESDAY...MOST LIKELY IN THE AFTERNOON TO EVENING HOURS...THOUGH
MODEL GUIDANCE STILL VARIES ON TIMING. THIS SYSTEM WOULD MOST LIKELY
BRING SNOW TO NORTHERN NM...BUT CENTRAL NM COULD RECEIVE SNOW GIVEN
A SLIGHT ADJUSTMENT IN THE TRACK OF THE STORM. THIS TROUGH WILL MOST
LIKELY KEEP TEMPERATURES BELOW NORMAL AND RELATIVE HUMIDITY ABOVE
NORMAL THROUGH MIDWEEK. WEAK HIGH PRESSURE WILL DRIFT ACROSS NM
WEDNESDAY WITH A GREATER POSSIBILITY FOR STRONGER MORNING INVERSIONS
AND POORER DAYTIME VENTILATION. 28
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
324 PM MST FRI FEB 22 2013
.DISCUSSION...
ANOTHER WEAK UPPER WAVE SLIDING ACROSS NORTHERN NM IN FAST NNW FLOW
WILL KEEP THE SNOW MACHINE GOING OVER THE HIGH TERRAIN THROUGH EARLY
SATURDAY. LOCAL HI RES WRF...NAM12...AND HRRR SOLUTIONS SHOW MESOSCALE
FEATURES WITHIN THE LARGER SCALE REGIME SLIDING SOUTHWARD OUT OF THE
NORTHERN MTS TONIGHT INTO THE RIO GRANDE VALLEY FROM SANTA FE TO THE
ABQ METRO AREA THIS EVENING. INCREASED POPS ACCORDINGLY AND PLACED A
DUSTING TO 1 INCH FOR THESE AREAS. FOR THE HIGH TERRAIN THERE HAS
BEEN AN EBB AND FLOW OF LIGHT TO MODERATE SNOW AND SNOW SHOWERS SINCE
THURSDAY MORNING WITH 1-4 INCHES OF SNOW EACH 12HR PERIOD ADDING UP
TO SOME MODEST ACCUMULATIONS. TONIGHT WILL FEATURE ANOTHER 1-4 INCHES
ABOVE 7500 FEET. A DISTINCT BREAK WILL TAKE SHAPE FOR THE ENTIRE
AREA SATURDAY BEHIND TONIGHTS UPPER WAVE.
A HIGHER IMPACT STORM WILL MOVE OVER NORTHERN NM SATURDAY NIGHT AND
SUNDAY. THIS SYSTEM WILL BRING WITH IT A STRONG PACIFIC COLD FRONT
AND ANOTHER ROUND OF WIND AND SNOW. THE NORTHERN MTS WILL SEE AN
ADDITIONAL SEVERAL INCHES OF SNOW BUT WITH MORE WIND AND COLDER
TEMPS THAN THE PAST 36 HRS SO SOME WINTER HIGHLIGHTS ARE EXPECTED.
THE NE PLAINS WILL BE IN THE ACTION AS WELL WITH A TROWAL FEATURE
SLIDING OVER THE AREA AS THE STORM SYSTEM DEEPENS OVER THE PLAINS
STATES. TEMPS WILL DIVE BACK 10 TO 20F BLW NORMAL ONCE AGAIN.
CONFIDENCE IS NOT HIGH ENOUGH FOR A WINTER STORM WATCH AT THIS
TIME BUT IF MODEL TRENDS CONTINUE TO STRENGTHEN THAT COULD CHANGE.
COLD TEMPS WILL CONTINUE INTO MONDAY AND TUESDAY WITH BREEZY TO
LOCALLY WINDY CONDITIONS EXPECTED. BY LATE TUESDAY GUIDANCE SHOWS
ANOTHER WAVE SLIDING SE OVER THE AREA WITH MORE SNOWFALL ACCUMS
FOR THE NORTHERN HIGH TERRAIN. ANOTHER BREAK IS ON TAP WEDNESDAY
BEFORE ANOTHER FAST MOVING SHEARED WAVE SLIDES OVER THURSDAY. BY
THE END OF THE WEEK GUIDANCE FINALLY STOPS THE WAVE TRAIN AND
SLOWLY PUSHES A RIDGE TOWARD THE AREA WITH SLIGHTLY WARMER TEMPS.
GUYER
&&
.FIRE WEATHER...
AN UPPER LEVEL TROUGH WILL MOVE RAPIDLY TO THE EAST ACROSS NORTHERN
NM TONIGHT PRODUCING LIGHT TO MODERATE SNOWFALL IN THE HIGHER
TERRAIN AND ISOLATED AREAS OF LIGHT SNOW IN THE LOWER ELEVATIONS.
MOIST NORTHWEST TO WEST FLOW ACROSS NORTHERN AND CENTRAL NM TONIGHT
WILL KEEP RELATIVE HUMIDITIES ABOVE NORMAL THROUGH SATURDAY MORNING.
INCREASING 700 MB WINDS AND THE FORMATION OF WEAK SURFACE LOW
PRESSURE IN EASTERN NM ON SATURDAY WILL RESULT IN WEST WIND GUSTS UP
TO 35 MPH EAST OF THE CENTRAL MOUNTAINS ALONG AND SOUTH OF I-40.
MINIMUM RELATIVE HUMIDITY IN THESE AREAS WILL GENERALLY BE IN THE
17-25 PERCENT RANGE...SO THE RISK OF CRITICAL FIRE WEATHER
CONDITIONS DEVELOPING SATURDAY AFTERNOON APPEARS LOW. VENTILATION
SATURDAY WILL BE FAIR TO GOOD WEST OF THE CONTINENTAL DIVIDE AND
GOOD TO VERY GOOD EAST OF THE DIVIDE.
A SIGNIFICANTLY STRONGER AND COLDER UPPER LEVEL LOW WILL MOVE FROM
THE EASTERN GREAT BASIN ACROSS NORTHERN AND CENTRAL NM SATURDAY
NIGHT THROUGH SUNDAY AND THEN EXIT ACROSS NORTHEASTERN NM SUNDAY
NIGHT. THE TRACK OF THIS SYSTEM HAS BEEN PROGRESSIVELY FURTHER TO
THE SOUTH ON MODEL RUNS OVER THE PAST 48 HOURS. THIS TRACK WILL
GENERATE THE STRONGEST WINDS ACROSS SOUTHERN NM ON SUNDAY. THE
DRIEST LOW LEVEL AIR AND STRONGEST WINDS WILL LIKELY STAY TO THE
SOUTH OF THE FIRE DISTRICT. WINDS WILL STILL BE MODERATE SUNDAY WITH
GUSTS BETWEEN 30 TO 35 MPH ACROSS CENTRAL NM...ESPECIALLY SOUTH OF
I-40. MOISTURE ACCOMPANYING THIS UPPER LEVEL TROUGH WILL KEEP
DAYTIME RELATIVE HUMIDITY VALUES NEAR OR ABOVE 20 PERCENT...SO
CRITICAL FIRE WEATHER CONDITIONS WILL BE UNLIKELY. SUSTAINED
NORTHWEST WINDS SUNDAY WILL RANGE FROM 10 TO 25 MPH....RESULTING IN
VERY GOOD TO EXCELLENT VENTILATION. AS THE UPPER LOW MOVES EASTWARD
ACROSS WESTERN OK SUNDAY NIGHT...WRAP-AROUND MOISTURE WILL KEEP
RELATIVE HUMIDITY HIGH ACROSS EASTERN NM....WHILE DECREASING WIND
SPEEDS AND RESIDUAL LOW LEVEL MOISTURE ACROSS CENTRAL AND WESTERN NM
WILL ALLOW FOR STRONG RELATIVE HUMIDITY RECOVERIES SUNDAY NIGHT
THROUGH MONDAY MORNING.
HIGH PRESSURE WILL BUILD ACROSS NM FROM THE WEST ON MONDAY WITH
LIGHTER WINDS AND DRIER LOW LEVEL AIR MOVING INTO THE REGION.
AFTERNOON WINDS IN THE EASTERN PLAINS WILL CREATE FAIR TO GOOD
VENTILATION...BUT LIGHTER WINDS ACROSS THE REMAINDER OF NM WILL
CREATE ONLY POOR TO FAIR VENTILATION.
ANOTHER UPPER LEVEL TROUGH MAY AFFECT NORTHERN AND CENTRAL NM ON
TUESDAY...MOST LIKELY IN THE AFTERNOON TO EVENING HOURS...THOUGH
MODEL GUIDANCE STILL VARIES ON TIMING. THIS SYSTEM WOULD MOST LIKELY
BRING SNOW TO NORTHERN NM...BUT CENTRAL NM COULD RECEIVE SNOW GIVEN
A SLIGHT ADJUSTMENT IN THE TRACK OF THE STORM. THIS TROUGH WILL MOST
LIKELY KEEP TEMPERATURES BELOW NORMAL AND RELATIVE HUMIDITY ABOVE
NORMAL THROUGH MIDWEEK. WEAK HIGH PRESSURE WILL DRIFT ACROSS NM
WEDNESDAY WITH A GREATER POSSIBILITY FOR STRONGER MORNING INVERSIONS
AND POORER DAYTIME VENTILATION. 28
&&
.AVIATION...
18Z TAF CYCLE
WEAK UPPER LEVEL TROUGH OVER SOUTHWEST CO THIS MORNING WILL MOVE
SOUTHEAST ACROSS NORTHERN NM LATE THIS AFTERNOON THROUGH THE EARLY
MORNING HOURS ON SATURDAY. WHILE THIS SYSTEM IS EXPECTED TO
PRODUCE ISOLATED LIGHT SNOW SHOWERS AND MOUNTAIN OBSCURATIONS
ACROSS THE HIGHER TERRAIN OF NORTHERN NM THROUGH MIDNIGHT...VFR
CLOUD DECKS ARE EXPECTED ACROSS THE LOWER ELEVATIONS AND AT THE
TAF SITES. THE 12Z RUN OF THE NAM MODEL CONTINUES TO SHOW A BAND OF
SNOW FORMING ACROSS THE MIDDLE RIO GRANDE VALLEY AFTER 00Z TONIGHT.
CONFIDENCE IN THE FORMATION OF THE SNOW BAND IS NOT HIGH HOWEVER...
SO INCLUDED TEMPO FOR LIGHT SNOW AT KABQ FROM 01Z TO 04Z. AFTER THIS
LOW PRESSURE SYSTEM MOVES EASTWARD INTO WESTERN TX...WEST WINDS
LESS THAN 10 KTS ARE EXPECTED ACROSS MOST OF THE REGION. HOWEVER...
WINDS IN THE FAR EASTERN PLAINS...INCLUDING KTCC...WILL SHIFT FROM
THE EAST TO THE NORTHEAST TONIGHT...AS LOW PRESSURE PASSES TO THE
NORTH. 28
&&
.PRELIMINARY POINT TEMPS/POPS...
FARMINGTON...................... 19 45 19 35 / 10 5 40 20
DULCE........................... 6 37 11 29 / 30 5 50 30
CUBA............................ 10 42 15 29 / 40 0 40 40
GALLUP.......................... 21 48 20 32 / 10 0 40 20
EL MORRO........................ 10 39 15 27 / 20 0 30 30
GRANTS.......................... 11 49 20 34 / 20 0 20 20
QUEMADO......................... 17 46 21 31 / 0 0 0 30
GLENWOOD........................ 15 53 26 44 / 0 0 0 10
CHAMA........................... 10 32 13 25 / 60 10 50 50
LOS ALAMOS...................... 19 40 20 30 / 40 0 10 40
PECOS........................... 18 37 20 30 / 50 0 0 40
CERRO/QUESTA.................... 3 37 11 27 / 60 0 20 60
RED RIVER....................... 5 32 10 20 / 80 5 30 70
ANGEL FIRE...................... -3 31 12 24 / 80 5 10 60
TAOS............................ 9 39 15 30 / 60 0 10 50
MORA............................ 15 42 17 29 / 50 0 0 50
ESPANOLA........................ 14 45 21 36 / 30 0 0 30
SANTA FE........................ 21 41 21 31 / 60 0 0 40
SANTA FE AIRPORT................ 18 44 23 34 / 40 0 0 30
ALBUQUERQUE FOOTHILLS........... 26 48 27 36 / 50 0 0 30
ALBUQUERQUE HEIGHTS............. 26 51 28 40 / 30 0 0 20
ALBUQUERQUE VALLEY.............. 22 52 25 41 / 30 0 0 10
ALBUQUERQUE WEST MESA........... 24 54 27 41 / 40 0 0 20
LOS LUNAS....................... 20 52 24 43 / 20 0 0 10
RIO RANCHO...................... 25 51 27 39 / 40 0 0 20
SOCORRO......................... 22 58 26 48 / 5 0 0 10
SANDIA PARK/CEDAR CREST......... 21 47 25 34 / 60 0 5 40
TIJERAS......................... 22 48 27 36 / 50 0 0 30
MORIARTY/ESTANCIA............... 21 45 23 34 / 40 0 0 20
CLINES CORNERS.................. 17 42 21 32 / 40 0 0 30
GRAN QUIVIRA.................... 21 45 24 37 / 10 0 0 20
CARRIZOZO....................... 21 50 28 44 / 0 0 0 20
RUIDOSO......................... 22 45 26 37 / 5 0 0 30
CAPULIN......................... 14 41 21 30 / 70 0 5 60
RATON........................... 14 47 23 34 / 50 0 5 50
SPRINGER........................ 17 49 23 35 / 40 0 0 40
LAS VEGAS....................... 14 47 23 32 / 40 0 0 40
CLAYTON......................... 20 48 27 36 / 50 0 0 40
ROY............................. 21 48 27 35 / 30 0 0 40
CONCHAS......................... 26 57 30 44 / 20 0 0 20
SANTA ROSA...................... 25 55 28 45 / 10 0 0 20
TUCUMCARI....................... 24 59 32 46 / 10 0 0 20
CLOVIS.......................... 24 56 30 48 / 5 0 0 10
PORTALES........................ 27 58 30 51 / 5 0 0 10
FORT SUMNER..................... 26 58 28 49 / 5 0 0 10
ROSWELL......................... 28 64 32 59 / 0 0 0 10
PICACHO......................... 24 58 33 52 / 0 0 0 10
ELK............................. 23 55 34 48 / 0 0 0 20
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
223 AM EST THU FEB 21 2013
.SYNOPSIS...
A NORTHWEST FLOW OF COLD AIR ACROSS THE FINGER LAKES WILL KEEP
LAKE EFFECT SNOW SHOWERS OVER CENTRAL NEW YORK INTO THURSDAY...
ALTHOUGH THE SNOW SHOWERS WILL WEAKEN AS HIGH PRESSURE BUILDS IN
AND SLOWLY CLEARS OUR SKIES. IT WILL REMAIN MOSTLY DRY ON FRIDAY
BEFORE A COMPLEX STORM SYSTEM OVER THE GREAT LAKES AND MID
ATLANTIC COAST PUSHES MIXED PRECIPITATION INTO THE AREA.
&&
.NEAR TERM /THROUGH TODAY/...
950 PM UPDATE...
LAKE BAND IS FINALLY SHOWING SIGNS OF A SOUTHWARD PUSH. WILL
CONTINUE GRID FORECAST UPDATED A FEW YEARS AGO, WITH THE NEXT
TARGET BECOMING NORTHERN ONONDAGA COUNTY. BAND IS STILL FORECAST
TO WEAKEN QUICKLY DUE TO COLLAPSING INVERSION HEIGHTS.
750 PM UPDATE...
STILL NO MOVEMENT SOUTHWARD TO LAKE BAND, WHICH IS SHOWING A
LITTLE MORE ORGANIZATION DEVELOPING. LATEST RAP DROPS THE BAND
INTO ONONDAGA COUNTY AROUND 3Z AND WEAKENS IT THEREAFTER.
AT THIS POINT I HAVE A HEALTHY DOSE OF SKEPTICISM REGARDING THE
NEWEST MESOSCALE MODEL RUNS, AS OTHERS HAVE HANDLED THE SITUATION
POORLY. SFC WIND AND PRESSURE OBSERVATIONS ARE NOT SUGGESTING A
BIG MOVE COMING. COULD ARGUE FOR EXTENDING THE ADVISORY FOR N.
ONEIDA, BUT DO NOT ANTICIPATE MORE THAN AN ADDITIONAL INCH OR TWO
TONIGHT.
610 PM UPDATE...
LAKE EFFECT BAND IS DEFYING THE SHORT TERM MODELS, AND IS
RESISTING THE FORECAST TO DRIFT SOUTHWARD INTO ONONDAGA COUNTY.
THE BAND HAS ALSO WEAKENED CONSIDERABLY IN THE LAST HOUR, THOUGH
WITH NIGHTTIME UPON US AND DAYTIME THERMALS LONG GONE, IT WOULD NOT
BE SURPRISING TO SEE REORGANIZATION.
THE GRIDS HAVE BEEN ADJUSTED TO DELAY THE LES ONSET INTO ONONDAGA-
MADISON BY 1-2 HOURS. WILL CONTINUE TO MONITOR BAND STRENGTH ONCE
IT MAKES ITS MOVE FOR POTENTIAL ADVISORY. SHOULD CURRENT RADAR
TRENDS HOLD, THERE WILL BE NO NEED FOR A FLAG.
3 PM UPDATE...
MESO SCALE MODELS AND FCST SNDGS SHOW THE BAND SLOWLY DRFTG
SOUTH OVRNGT AND WEAKENING. CRNT KTYX 88D IMAGES SHOW A SOMEWHAT
MORE DISORGANIZED BAND NOW IN THE ADVISORY AREA AND INDEED VERY
SLOWLY MVG SOUTH. SOMEWHAT CNRND THAT ANOTHER SPOKE ROTATING ARND
THE UPR LOW COULD DELAY THE SWRD MVMT AND QUICKLY GIVE PART OF THE
FCST AREA NEAR ADVISORY SNOW THIS EVE. AIR STILL PLENTY COLD WITH
-14C AIR CORE OVER THE LAKE. HWVR...SINKING MOTION SHOWN IN THE
SNDGS CONTS TO LWR THE INV PTNLY WEAKENING THE BAND REGARDLESS OF
THE FLOW. ATTM WILL CONT WITH THE ADVISORY FOR NRN ONEIDA AND PUT
ACCUMS JUST BLO CRITERIA IN NRN ONONDAGA AND SRN ONEIDA.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY/...
LE WILL LINGER INTO THU WITH CONTD COLD AIR AND NW FLOW. HIPRES
SFC AND ALOFT FNLY BLDS IN FOR FRI AS THE CLSD LOW DRIFTS EAST IN
RESPONSE TO THE DVLPG COMPLEX OVER THE CNTR OF THE COUNTRY. FRI
LOOKS SUNNY WITH SLGTLY ABV NRML TEMPS.
COMPLEX SCENARIO AND TRICKY FCST UNFOLDING FOR THE END OF THE SHRT
TERM. YET ANOTHER CLSD LOW OVER THE GREAT LAKES TRIES TO PHASE
WITH A SRN STREAM SHRT WV TRAVELING UP THE EAST CST. MODELS
TYPICALLY HAVE TROUBLE WITH DVLPG LOWS AND THIS IS COMPLICATED BY
THE DFCLTY IN PLACING THE MEANDERING CLSD UPR LOW OVER THE WRN
LAKES. CONSENSUS NOW IS TO DVLP THE SRN STREAM IMPULSE ENOUGH TO
PUSH MORE SUBSTANTIAL PCPN BACK INTO THE SERN ZONES...NAMELY THE
PA AND THE WRN CATS. OTR COMPLICATING FACTOR IS PCPN TYPE WITH A
COMPLETE LACK OF COLD AIR...EVEN OVER NRN NEW ENG. SO...IT LOOKS
VERY MUCH LIKE AN EARLY SPRING LIKE SCENARIO WITH MIXED PCPN...OR
LRG VLY/HILL DFRNCS. CNRT WWE FCST GIVE THE SERN ZONES A 4 TO 6
INCH ACCUM...2 TO 4 ELSEWHERE. WILL CONT A MENTION IN THE HWO FOR
NOW AND XPCT CONTG CHGS TO THE FCST AS THE WEEKEND APRCHS.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
1 PM UPDATE...
BLOCKY PATTERN WITH TWO CLOSED LOWS MOVING THROUGH IN THE LONG
TERM. BOTH APPEAR TO BE MINOR FOR THE CWA. THE FIRST WILL BE
FRIDAY TO SUNDAY. THE UPPER LEVEL LOW WILL BE IN THE GREAT LAKES
SAT NGT WITH A NOREASTER FORMING. MOST MODELS HAVE A NEAR MISS.
THE TROF GOES NEGATIVE TILT WHICH SLOWS THE SNOW FROM EXITING
UNTIL SUNDAY. A WEAK LAKE RESPONSE ON THE BACK SIDE OF THE STORM
SUNDAY NIGHT TO MONDAY. LATE MONDAY A LARGE AREA OF HIGH PRESSURE
MOVES IN AT THE SFC AND ALOFT.
TUESDAY TO WEDNESDAY DO IT ALL OVER AGAIN WITH ANOTHER STACKED
LOW. THE EURO HANDLES THIS STORM SLOWER WITH THE LOW IN ILLINOIS
TUES MORN MOVG TO SSM WED. WARM AIR COMES NORTH WITH THE OCCLUDED
FRONT SO PRECIP WILL BE MIXED. THE GFS BRINGS THE STACKED LOW ENE
OVER NY/PA SO A BETTER CHC OF SNOW.
&&
.AVIATION /07Z THURSDAY THROUGH MONDAY/...
06Z UPDATE...
A COLD NORTHWEST FLOW WILL PERSIST THROUGH THIS TAF PERIOD
BRINGING A CONTINUATION OF SNOW SHOWERS AND FLURRIES. THE BEST
CHANCE FOR MORE ORGANIZED LAKE SNOWS WILL BE THROUGH 12Z
ESPECIALLY AT KSYR AND KRME...WITH A GRADUAL TRANSITION TO LIGHTER
SNOW FLURRIES AND SHOWERS FOR THE REMAINDER OF THURSDAY.
AT KRME...GENERALLY IFR WILL CONTINUE THROUGH 09Z IN STEADYER SNOW
SQUALLS. AFTER 09Z THE HEAVIER BAND WILL THEN DROP SOUTH OF THE
TERMINAL WITH MVFR SNOW SHOWERS EXPECTED THROUGH DAYBREAK WITH A
GRADUAL RETURN TO VFR WITH CIGS AROUND 3,500 FT AFTER THAT TIME.
AT KSYR...IFR WITH OCCASIONAL BELOW ALT MIN CONDITIONS THROUGH
09Z. AFTER 09Z SOME IMPROVEMENT POSSIBLE BUT CONFIDENCE NOT HIGH
ENOUGH AND ELECTED TO KEEP THE POSSIBILITY OF IFR VSBYS IN THROUGH
12Z. AFTER THAT TIME WE SHOULD IMPROVE TO MVFR IN SNOW SHOWERS AND
FLURRIES THROUGH AFTERNOON.
AT KITH/KBGM...GENERALLY MVFR CONDITIONS DUE TO CIGS WITH
OCCASIONAL MVFR VSBY RESTRICTIONS IN SNOW SHOWERS THROUGH
DAYBREAK. FLURRIES AND BRIEF HEAVIER SQUALLS LIKELY TO PERSIST THROUGH
THURSDAY AFTN AT KITH.
AT KELM/KAVP...GENERALLY VFR WITH CIGS AROUND 4K FT AND SNOW FLURRIES.
WEST WINDS 10-15 KNOTS WITH GUSTS AROUND 25 KNOTS DURING THE
DAYLIGHT HOURS ON THURSDAY.
.OUTLOOK...
THU NGT/FRI MORN...VFR.
FRI AFTN TO SAT NGT...MVFR/IFR IN MIXED PCPN.
SUN...VFR...MAYBE MVFR IN NY WITH LAKE ENHANCED SNOW SHOWERS.
MON...VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DGM
NEAR TERM...DGM/DJP
SHORT TERM...DGM
LONG TERM...TAC
AVIATION...HEDEN/RRM
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
1015 PM EST FRI FEB 22 2013
.SYNOPSIS...
LOW PRESSURE WILL APPROACH FROM THE SOUTHWEST TONIGHT AND MOVE
ACROSS EASTERN NORTH CAROLINA SATURDAY. HIGH PRESSURE WILL PASS TO
THE NORTH SUNDAY NIGHT AND MONDAY. LOW PRESSURE AND ITS TRAILING
COLD FRONT WILL MOVE THROUGH TUESDAY. LOW PRESSURE WILL LINGER
OVER THE MID ATLANTIC STATES WEDNESDAY AND THURSDAY.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
AS OF 1014 PM FRI...SHOWERS STILL REMAIN ISOLATED OVER EASTERN NC
TONIGHT WITH MAIN BULK OF RAIN IN GA. NICE CONVERGENCE ALONG THE
COAST AS TROUGH GAINS BETTER DEFINITION. RUC CONTINUES TO HAVE BEST
HANDLE ON CURRENT PATTERN. IT MOVES THE MAIN PRECIP INTO NC AROUND
SUNRISE. WILL ADJUST TIMING IN GRIDS. NEW FORECAST SOUNDINGS DRYING
THINGS OUT A LITTLE SOONER THAN PREVIOUS...BUT THAT IS IN THE NEXT
PERIOD.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH 6 PM SATURDAY/...
AS OF 315 PM FRI...WIDESPREAD RAIN CONTINUES FOR THE FIRST HALF OF
SATURDAY AS LOW PRESSURE TRACKS DIRECTLY ACROSS EASTERN NORTH
CAROLINA. DUE TO THE LOW TRACK...HIGHS ALONG THE COASTAL PLAIN
WILL BE IN THE UPPER 40S TO LOWER 50S...BUT CLOSER TO THE COAST IN
THE WARM SECTOR HIGHS WILL CLIMB TO THE UPPER 50S TO NEAR 60. RAIN
WILL TAPER OFF IN COVERAGE BEGINNING AROUND MIDDAY AND CONTINUING
INTO THE AFTERNOON AS THE LOW MOVES OFF TO THE NORTHEAST. LOOKS
LIKE ANOTHER INCH OR SO POSSIBLE FROM DAYBREAK SATURDAY THROUGH
MIDDAY...WITH LIGHTER AMOUNTS IN THE AFTERNOON.
&&
.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
AS OF 315 PM FRI...PRECIPITATION WILL BE GRADUALLY TAPERING OFF
SAT NIGHT AS MID LEVEL SHORT WAVE CROSSES THE AREA LATE AT NIGHT.
WITH HIGH PRESSURE BUILDING IN FROM THE OHIO VALLEY UNDER WNW FLOW
ALOFT...THE LATTER HALF OF THE WEEKEND WILL BE DRY AND SEASONAL
WITH HIGHS SUNDAY IN THE UPPER 50S AND LOWER 60S WITH LOWS SUNDAY
NIGHT IN THE MID TO UPPER 30S INLAND TO LOW 40S COAST.
CLOUDING UP ON MONDAY AS THE NEXT SOUTHERN STREAM SYSTEM LIFTS NE OF
THE GULF COAST. MAY SEE SOME LIGHT RAIN REACH SOUTHERN AREAS DURING
THE AFTN BUT THE BULK OF THE PRECIPIATATION WILL BE WITH A NORTHWARD
MOVING WARM FRONT LATER MON NIGHT INTO EARLY TUE. MAY ALSO SEE
SCATTERED SHOWERS ALONG AND AHEAD OF ASSOCD COLD FRONT TUESDAY
AFTN/EVE. RAINFALL AMOUNTS MAY AGAIN EXCEED AN INCH WITH THIS
SYSTEM. HIGHS MONDAY WILL BE HELD IN THE 50S BY INCREASING AFTN
CLOUD COVER TEMPS BUT WILL REBOUND INTO THE LOW 60S OR HIGHER IN
BRIEF WARM SECTORING TUE AFTN. WED WILL BE DRY AND A BIT COOLER AS
WEAK HIGH PRESSURE BUILS INTO THE AREA.
UPPER PATTERN WILL BECOME HIGHLY AMPLIFIED DURING THE END OF THE
WEEK AS A DEEP TROF DEVELOPS OVER THE EASTERN STATES. SHUD SEE A
SERIES OF MAINLY DRY COLD FRONTAL PASSAGES GIVEN THE APPARENT LACK
OF DEEP MOISTURE SOURCES IN THE OVERALL WESTERLY FLOW. TEMPS WILL
SHOW A GRADUAL COOLDOWN AS POST FRONTAL CAA SETS IN. HIGHS IN THE
MID 50S THU WITH UPPER 40S TO LOW 50S FRI.
&&
.AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
SHORT TERM /TONIGHT & SAT/
AS OF 625 PM FRI...FEW LIGHT SHOWERS ACROSS AREA TAFS THIS EVENING.
MAIN AREA OF PRECIP STILL IN GA/AL AREA. RUC/RAP MODEL HAS BEST
HANDLE ON CURRENT CONDITIONS AT THIS TIME...EVEN THOUGH THEY ARE A
LITTLE OVERDONE. AREA SOUNDINGS SHOWING NON-SATURATED LOWER
LEVELS...BUT FORECAST SOUNDINGS SHOWING LOWER LEVELS WILL SATURATE
IN THE NEXT FEW HOURS. LOOKS LIKE THE MAIN BULK OF THE PRECIP WILL
GET TO EASTERN NC AROUND 7 TO 8Z. IFR/LIFR CONDITIONS EXPECTED LATER
TONIGHT AND THROUGH MUCH OF THE DAY SATURDAY. SOME MODELS SHOWING
FORCING MOVING A BIT EAST COMPARED TO PREVIOUS GUIDANCE. WILL KEEP
AN EYE ON THINGS...BUT EITHER WAY WILL HAVE LOWERED VIS/CIG THROUGH
THE DAY.
LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 315 PM FRI...SUB-VFR CONDITIONS LINGER INTO SAT NIGHT THEN
IMPROVING FLYING CONDITIONS AS DEEPER DRYING SETS IN BEHIND A A
COLD FRONT MOVING OFFSHORE EARLY SUNDAY. EXPECT VFR SUNDAY AND
MONDAY BEFORE LIKELY SUB-VFR THRESHOLDS AHEAD OF A LOW PRESSURE
SYSTEM MOVING NE FROM THE GULF MONDAY NIGHT INTO TUESDAY.
CONDITIONS IMPROVE AGAIN WITH VFR EXPECTED TUESDAY NIGHT INTO
WEDNESDAY AS COLD FRONT PASSES EAST OF THE AREA.
&&
.MARINE...
SHORT TERM /TONIGHT & SAT/...
AS OF 1015 PM FRI...NORTHEASTLY WIND AROUND 10 KNOTS THIS EVENING
OVER THE COASTAL WATERS. CONVERGENCE ALONG THE COAST WITH RIDGING IN
THE CENTRAL PART OF THE STATE. WIND WILL BECOME MORE SOUTHEASTERLY
AS COASTAL CONVERGENCE BECOMES MORE WELL DEFINED. WAVE WILL FORM
ALONG THE COASTAL TROUGH OFF SC/GA TONIGHT AND RIDE UP ALONG THE
COAST AS IT DEEPENS. WIND AND SEAS WILL PICK UP AS SURFACE LOW
PRESSURE APPROACHES THE AREA AND GRADIENT TIGHTENS. MAIN BULK OF
RAIN WILL GET TO THE COASTAL WATERS BETWEEN MIDNIGHT AND SUNRISE AND
WILL CONTINUE THROUGHOUT THE DAY ON SATURDAY WITH REDUCED
VISIBILITIES AND HEAVY RAINFALL LIKELY.
LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 315 PM FRI...COLD FRONT PASSES THRU THE MARINE AREA SAT
EVENING WITH SCA CONDITIONS CONTINUING THRU EARLY SUNDAY.
WINDS/SEAS GRADUALLY DECREASE SUNDAY AS HIGH PRESSURE BUILDS IN
FROM THE NW. WINDS THEN VEER AND INCREASE AGAIN MONDAY AHEAD OF
THE NEXT LOW PRESSURE SYSTEM LIFTING NE FROM THE GULF COAST.
WINDS/SEAS LIKELY EXCEED SCA CRITERIA LATE MONDAY NIGHT INTO
TUESDAY AS WINDS SHIFT SW BEHIND WARM FRONT PUSHING NORTH OF THE
AREA. WINDS/SEAS DECREASE AGAIN WED AS WEAK HIGH PRESSURE BUILDS
OVER THE AREA.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 4 AM SATURDAY TO 7 AM EST SUNDAY FOR
AMZ152-154.
SMALL CRAFT ADVISORY FROM 1 AM SATURDAY TO 1 AM EST SUNDAY FOR
AMZ156-158.
SMALL CRAFT ADVISORY FROM 7 AM TO 9 PM EST SATURDAY FOR AMZ150.
&&
$$
SYNOPSIS...HSA
NEAR TERM...CGG
SHORT TERM...HSA
LONG TERM...BTC
AVIATION...CGG/BTC
MARINE...CGG/BTC
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
950 AM CST THU FEB 21 2013
.DISCUSSION...
FORECAST CHALLENGE FOR UPDATE CONCERNS CLOUD TRENDS AND
TEMPERATURES. SEVERAL CLOUD AREAS TO POTENTIALLY AFFECT FA TODAY.
VFR CIGS CONTINUE TO LIFT NORTH THROUGH FAR WESTERN FA. ALSO SOME
WEAK RETURNS FROM KMVX-88D OVER DVL BASIN HOWEVER METARS SO FAR
REPORTING NO PCPN AND RETURNS LIKELY PICKING UP ON CIGS. WITH
NEAREST MEASURABLE SNOW FROM BIS-MOT WILL JUST MENTION FLURRIES
REMAINDER OF AM. CI SHIELD FROM CENTRAL PLAINS STORM LIFTING N
AROUND 35KTS AND CURRENT TRENDS WOULD HAVE MOST OF FA AFFECTED BY CI
BY EARLY AFTERNOON. STILL NOT MUCH CONFIDENCE ON DEGREE OF WESTWARD
ADVANCE OF STRATUS COMING OFF OF LAKE SUPERIOR AND WILL CONTINUE TO
MONITOR FOR AVIATION PURPOSES. WITH FILTERED SOLAR AFFECTING MOST
AREAS FEEL CURRENT TEMPERATURES IN LINE SO WILL BE MAKING MINIMAL
CHANGES. WILL MAKE THE POP AND CLOUD TREND ADJUSTMENTS WITH THE
REMAINDER OF THE FORECAST OK.
&&
.AVIATION...
EXPECT VFR CONDITIONS WITH SOME LOWER VFR CIGS NEAR KDVL FOR TODAY.
WILL NEED TO MONITOR THE POTENTIAL FOR LOWER CIGS ADVECTING INTO THE
REGION FROM THE EAST THIS AFTERNOON. 12Z RAP INDICATES LOWER CIGS
ACROSS NORTHEAST MINNESOTA WILL EXPAND WESTWARD...AND OBSERVATIONS
HAVE SHOWN SOME WESTWARD MOVEMENT OF THE LOWER CIGS. WILL AT LEAST
HINT AT A LOWER CLOUD DECK FOR KBJI THIS AFTERNOON IN THE TAF.
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
VOELKER/JAM
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
311 AM CST THU FEB 21 2013
.SHORT TERM...(TODAY THROUGH SATURDAY NIGHT)
CHALLENGE WILL BE TEMPERATURES AND LIGHT SNOW CHANCES. 00Z MODELS
IN AGREEMENT AND WILL USE A BLEND FOR THE FORECAST. NO BIG CHANGES
REQUIRED TO THE FORECAST.
COULD BE SOME FLURRIES OR VERY LIGHT SNOW ACROSS THE DEVILS LAKE
BASIN THIS MORNING...BUT MODELS ALL INDICATE RIDGING AND LOW LEVEL
EASTERLY DRY FLOW WILL KEEP ACCUMULATING SNOWFALL TO THE WEST.
HAVE REMOVED POPS/WX FOR TODAY INTO THE EVENING HOURS. AFTER
MIDNIGHT...UPPER LOW WILL TRACK INTO IOWA AND CONTINUE SLOWLY INTO
NORTHERN WISCONSIN BY FRIDAY EVENING. THE SOUTHEAST FA WILL BE
NEAR THE NORTHERN END OF SNOW SHIELD...AND MODELS ALL AGREE AROUND
AN INCH OF SNOW POSSIBLE ON BY FRIDAY AFTERNOON. KEPT THE IDEA OF
HIGH POP/LOW QPF. RIDGING THEN DOMINATES ON SATURDAY.
TEMPERATURES WILL BE CHALLENGING AND HIGHLY DEPENDENT ON CLOUD
COVER...ESPECIALLY AT NIGHT. FOR TODAY...WITH SOLAR EXPECTED
ACROSS THE EASTERN FA...THINKING THE FORESTED AREAS WILL BE ABLE
TO WARM INTO THE MID/UPPER 20S. WITH A WARMER START COMPARED TO
YESTERDAY...THE REMAINDER OF THE FA SHOULD BE ABLE TO WARM INTO
THE TEENS. MID-UPPER CLOUDS EXPECTED TO OVERTAKE THE REGION
TONIGHT...WHICH WILL LIMIT TEMPERATURE FALL. THE MAIN QUESTION
WILL BE AREAS THAT ARE CLEAR THIS EVENING...AND HOW FAR THEY WILL
FALL BEFORE CLOUDS ARRIVE. ON FRIDAY...EXPECT MOSTLY CLOUDY SKIES
WHICH WILL LIMIT MAX TEMPS ACROSS THE REGION TO AROUND 20F. WEAK
FLOW AND SIMILAR AIRMASS TEMPERATURES REMAIN INTO SATURDAY. IF
THERE IS SOLAR ON SATURDAY EXPECT THE FORESTED AREAS TO BE
WARMER...AND IF/WHERE SKIES ARE CLEAR AT NIGHT EXPECT VALUES JUST
BELOW ZERO. DID LOWER MIN TEMPS A BIT...BUT NOT TOO CRAZY.
.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
MEDIUM-RANGE MODELS AGREE THAT THE NORTHERN PLAINS WILL BE IN A
SPLIT FLOW PATTERN WITH THE MAJORITY OF SYNOPTIC ENERGY ACROSS THE
SOUTHERN CONUS. ANOTHER FOUR CORNERS LOW AND ITS SNOW MAY CLIP THE
SOUTHEASTERN FORECAST AREA EARLY NEXT WEEK...BUT OVERALL MODEL
TRENDS CONTINUE TO KEEP THE MAJORITY OF PRECIPITATION SOUTH AND EAST
INTO MN/WI/IA. SEVERAL WEAK WAVES COULD IMPACT THE REGION THROUGH
THE PERIOD...BUT MODEL TIMING AND PLACEMENT AGREEMENT IS POOR. AS A
RESULT...WILL KEEP LOW-END (20-30 PERCENT) ALL BLEND POPS. WITH NO
MAJOR CHANGES IN AIR MASS...EXPECT LITTLE DAY TO DAY TEMPERATURE
VARIATION. AFTERNOON HIGHS WILL BE IN THE 20S AND NIGHTTIME LOWS
WILL BE IN THE TEENS.
&&
.AVIATION...
EXPECT VFR CONDITIONS WITH SOME LOWER VFR CIGS NEAR KDVL FOR
TODAY. WILL NEED TO MONITOR THE POTENTIAL FOR LOWER CIGS ADVECTING
INTO THE REGION FROM THE EAST THIS EVENING. 06Z RAP INDICATES
LOWER CIGS ACROSS NORTHERN WISCONSIN WILL EXPAND. CONFIDENCE IS
LOW THAT THIS WILL ACTUALLY OCCUR...BUT SOMETHING TO MONITOR.
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
TG/ROGERS
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
807 PM CST FRI FEB 22 2013
.UPDATE...
LATEST REGIONAL RADAR IMAGERY SHOWS SCATTERED RAIN ACROSS NORTHERN
MISSISSIPPI AND ALABAMA INTO EAST TENNESSEE. ACTIVITY HAS BEEN
REMAINING TO THE SOUTHEAST OF THE CWA SO FAR...AND APPEARS THIS
TREND WILL CONTINUE THROUGH MUCH OF THE NIGHT WITH ONLY THE FAR
EASTERN AND SOUTHEASTERN ZONES LIKELY TO BE AFFECTED BY ANY
PRECIP. WITH SHORT TERM GUIDANCE INCLUDING THE HRRR AND 00Z NAM
AGREEING WITH THIS SCENARIO...WILL TRIM POPS BACK FURTHER TOWARDS
THE SOUTHEAST. WILL ALSO KEEP IN MENTION OF PATCHY FOG OVER THE
SOUTHEAST HALF OF THE CWA AS DEWPOINT DEPRESSIONS ARE ALREADY
LOW...AND WILL BE SEVERAL HOURS BEFORE APPROACHING COLD FRONT OVER
NORTHWEST ZONES REACHES THIS AREA. REST OF FORECAST APPEARS TO BE
ON TRACK.
&&
.PREV DISCUSSION... /ISSUED 641 PM CST FRI FEB 22 2013/
UPDATE...FOR 00Z TAFS...
AVIATION...
MAINLY VFR CONDITIONS THIS EVENING FOR CKV AND BNA. AFTER MIDNIGHT
CEILINGS ARE EXPECTED TO LOWER TO MVFR CONDITIONS...WITH IFR
CONDITIONS POSSIBLE IN NASHVILLE AS CIGS DROP BELOW 1000 FEET IN
THE EARLY MORNING HOURS. CONDITIONS AT CSV REMAIN WITHIN IFR
CONDITIONS WITH CONDITIONS DETERIORATING AS THE NIGHT PROGRESSES.
CEILINGS ARE FORECAST TO CONTINUE LOWERING THIS EVENING AS A BAND
OF MOISTURE MOVES JUST SOUTH AND EAST OF THE MID STATE. VIS AT CSV
MAY BE REDUCED TO 1 MILE OR LESS SATURDAY MORNING DUE TO FOG.
CONDITIONS SHOULD IMPROVE CLOSER TO NOON ON SATURDAY AS A FRONT
PASSES THROUGH THE AREA.
PREV DISCUSSION... /ISSUED 320 PM CST FRI FEB 22 2013/
DISCUSSION...
TEMPS DROP OFF CONSIDERABLY TO THE WEST OF NASHVILLE BEHIND THE COLD
FRONT. THIS BOUNDARY IS RUNNING PARALLEL TO THE UPPER FLOW BUT WILL
SLOWLY MOVE THROUGH AND WILL REACH EAST TN TONIGHT. THE BOUNDARY
WILL THEN SLOW DOWN AND STALL. SFC ENERGY WILL THEN LIFT NE ALONG
THE BOUNDARY AND SPREAD MOISTURE NORTHWARD. LOOKS AS THOUGH THE
MOISTURE WILL FOR THE MOST PART STAY SOUTH OF MIDDLE TN.
ALTHOUGH...SOME SHOWER ACTIVITY COULD REACH THE PLATEAU AND SRN
AREAS OVERNIGHT. WILL INCLUDE LOW POPS FOR EASTERN AND SOUTHERN
PORTIONS. OTHERWISE...DESPITE THE FROPA AND SOME LOWERING DEW
POINTS...DEW POINT DEPRESSIONS WILL BE RATHER LOW BY
12Z...PARTICULARLY ACROSS THE EASTERN HALF OF THE CWA. WILL ALSO
INCLUDE SOME PATCHY LATE NIGHT FOG.
ON SATURDAY...SFC HIGH WILL BUILD IN WITH SOME DRIER AIR WINNING
OUT. THIS TREND WILL CONTINUE INTO SUNDAY...AND WITH AMPLIFIED
HEIGHTS...SHOULD SEE TEMPS BACK UP INTO THE 50S FOR BOTH DAYS.
IN THE EXT FCST...MODELS ARE CONTINUING TO TREND TOWARD A COLDER AND
SOMEWHAT UNSETTLED PATTERN. UPPER LEVEL TROUGHING IS EXPECTED
WITH SEVERAL DISTURBANCES MOVING THROUGH THE AREA.
THE FIRST SYSTEM WILL BE ON MONDAY WITH A POTENT NEGATIVELY TILTED
UPPER LOW AXIS. THIS FEATURE WILL PASS NORTH OF TN AND WILL DRAG AN
ASSOCIATED FROPA THROUGH ON TUESDAY. RAIN PROBABILITIES LOOK HIGH
FOR MONDAY INTO TUESDAY. SYNOPTIC FEATURES SUPPORT THE POTENTIAL FOR
SOME WRAP AROUND SNOWFALL. HOWEVER...MODEL SFC TEMPS LOOK TOO WARM
AND EVEN A 5 DEGREE UNDERCUT WILL NOT SUPPORT SUFFICIENTLY LOW
ENOUGH FREEZING LEVEL SUPPORT. THUS...WILL LEAN TOWARD MOSTLY RAIN
FOR TUESDAY.
WED NT INTO THU...NEXT IMPULSE TO MOVE THROUGH. MODELS CONVERGE TO
SUPPORT TEMPS THAT WILL BE COLD ENOUGH TO SUPPORT AM
RAINFALL/SNOWFALL...RAIN IN AFTERNOON. SYSTEM DOES NOT CARRY AN
ABUNDANCE OF ORGANIZATION SO WILL KEEP POPS LOW. GFS THEN LEANS
TOWARD YET ANOTHER DISTURBANCE FOR FRIDAY. WILL OPT TO KEEP A
FLURRIES OR LIGHT SNOW SHOWERS GOING THU NT AD FRIDAY.
FOR THE EXT TEMPS...IT WILL BE DO OR DIE TIME VERSUS THE GUIDANCE.
MEX IS CARRYING HIGHS OF 45 TO 50 FOR BNA. THE MODELS ARE ALL
CONVERGING ON LOW HEIGHTS...CLOUDS AND SOME PRECIP...AD 850 MB TEMPS
OF UP TO -5 TO -10. WILL ROLL THE DICE AND UNDERCUT THE MEX NUMBERS
DECISIVELY. PERHAPS JUST A SLIGHT UNDERCUT ON OVERNIGHT LOWS.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
55
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1133 PM CST WED FEB 20 2013
.AVIATION...
WILL MAINTAIN CONTINUITY OF PREVIOUS FORECASTS CONCERNING TIMING
OF SQUALL LINE AND COLD FRONT. HOWEVER...WE DID MODIFY THE TIMING
OF LOWERING CLOUD BASES AND ARRIVAL OF IFR CIGS ACROSS THE
METROPLEX AND KACT.
SHRA ACTIVITY WILL INCREASE FOR KACT AFTER 07Z AS THE SFC-850 FRONT
LIFTS NORTHWARD AND FORCING FOR LIFT INCREASES. AS FOR THE
METROPLEX...WE/RE LOOKING FOR THIS PROCESS TO GEAR UP 08-10Z. THE
TIMING OF THE SQUALL LINE STILL LOOKS GOOD...13-16Z FOR THE
METROPLEX AND 14-16Z FOR KACT.
LOW-LEVEL WIND SHEAR WILL REMAIN A PROBLEM TONIGHT AS LOCAL 88D RADAR
VAD PROFILES SHOW 50+ KNOTS AROUND 2-3 KFT AND GENERALLY 25-30
KNOTS AT 1 KFT AGL. HAVE INCLUDE THIS CAUTION IN ALL TAFS. 75
&&
.UPDATE...
A MINOR UPDATE TO LOWER RAIN CHANCES THROUGH LATE EVENING INTO THE
FIRST FEW HOURS OF THURSDAY MORNING...AS NORTH TEXAS IS IN A LULL
BETWEEN DISTURBANCES. THE FIRST DISTURBANCE THAT GAVE THE RAIN AND
A LITTLE BIT OF SLEET TO PARTS OF NORTH TEXAS EARLIER TODAY IS
HEADING AWAY FROM THE AREA AND CAUSING WINTER WEATHER PROBLEMS
ACROSS PARTS OF OKLAHOMA INTO ARKANSAS/MISSOURI.
THE MAIN SYSTEM THAT WILL AFFECT NORTH TEXAS BY DAYBREAK THURSDAY
MORNING IS JUST STARTING TO ROTATE OUT OF ARIZONA AND INTO WESTERN
NEW MEXICO AT 9 PM. LINEAR FORCING WAS HELPING TO DEVELOP A LINE
OF STORMS ACROSS FAR SOUTHEAST NEW MEXICO AND TO THE TEXAS STATE
LINE. NOT ALL MODELS ARE IN SUCH AS THE 00Z GFS...HOWEVER THE 00Z
NAM...TEXAS TECH WRF AND HRRR MODELS ARE SHOWING IT WILL BE AFTER
3 AM BEFORE THINGS BEGIN TO GET ACTIVE ACROSS THE WESTERN HALF OF
THE AREA. ONE THING TO NOTE OF THE WRF AND 00Z NAM MODELS HOWEVER
WAS THEY WERE TOO FAR EAST FROM LUBBOCK TO MIDLAND WITH THE
DEVELOPING SQUALL LINE AT MID EVENING.
THE SURFACE WARM FRONT WHICH IS NOW OVER SOUTH-CENTRAL TEXAS WILL
ONLY CREEP NORTH WITH THE BEST NORTHWARD SURGE OCCURRING WEST/SOUTHWEST
OF OUR AREA CLOSER TO THE BETTER HEIGHT FALLS AND SURFACE LOW
CURRENTLY OVER ALPINE AND FAR WEST TEXAS. STRONG 850MB WAA WILL SLIDE
EAST ACROSS WESTERN NORTH TEXAS BETWEEN 3-6 AM...AND THIS WILL BE
THE TIME STORMS AND A FEW SUPERCELLS WILL DEVELOP. BEST CHANCE FOR
SURFACE-BASED SEVERE STORMS WITH DAMAGING WINDS AND TORNADOES WILL
BE IN A LIMITED TIME WINDOW FROM 5AM-9AM AND GENERALLY SOUTH OF A
HAMILTON-WACO-ATHENS OR PALESTINE LINE. WITH 0-6KM SOUTHWESTERLY
SHEAR ON THE ORDER OF 70-90 KTS AND SOMEWHAT VEERED 0-1KM ON THE
ORDER OF 40-50 KTS...SUPERCELLS ARE HIGHLY LIKELY. ELEVATED
SUPERCELLS WILL OCCUR NORTH OF THE WARM FRONT WITH VERY LARGE
HAIL...FREQUENT LIGHTNING...AND HEAVY DOWNPOURS THE MAIN THREATS.
WE WILL CONTINUE TO MONITOR THIS SYSTEM DURING THE OVERNIGHT AND
URGE EVERYONE TO KEEP ON EYE THINGS AS THEY WAKE UP AND BEFORE
HEADING OUT FOR THE MORNING COMMUTE THURSDAY MORNING. SPOTTER AND
HAMS COULD EASILY BE ACTIVATED ACROSS THE WESTERN HALF OF THE CWA
BEFORE SUNRISE.
05/
&&
.PREV DISCUSSION... /ISSUED 330 PM CST WED FEB 20 2013/
CLOUDY AND COOL CONDITIONS PERSIST ACROSS THE REGION THIS
AFTERNOON WITH JUST A FEW SCATTERED AREAS OF LIGHT RAIN/SHOWERS
ACROSS THE REGION. THE UPPER LEVEL SYSTEM THAT WE HAVE BEEN
MONITORING TO BRING US STORMS AND A THREAT FOR SEVERE WEATHER
TONIGHT/THURSDAY IS NOW MOVING INTO SOUTHERN ARIZONA. THE
ASSOCIATED PACIFIC FRONT IS ALSO MOVING INTO ARIZONA...AND THIS
ENTIRE SYSTEM HAS QUITE A WAYS TO TRAVEL BEFORE ARRIVING IN NORTH
AND CENTRAL TEXAS.
FOR THE REST OF TODAY AND EARLY TONIGHT...RAIN ACTIVITY WILL BE
ISOLATED TO SCATTERED IN NATURE BUT OVERALL IT WILL BE A QUIET
EVENING. THEREFORE LOWERED POPS FOR THE EVENING HOURS AND ALSO
REMOVED THE MENTION OF THUNDER. THE RAIN ACTIVITY THROUGH THE
NIGHT WILL MAINLY COME FROM INCREASING ISENTROPIC LIFT ASSOCIATED
WITH WARM AIR ADVECTION OVER THE COOL SURFACE BOUNDARY LAYER. MUCH
LATER TONIGHT...LIFT FROM THE APPROACHING UPPER LEVEL LOW WILL
BEGIN TO SPREAD OVER THE REGION AND WILL LIKELY SEE AN INCREASE IN
CONVECTIVE/THUNDERSTORM ACTIVITY DURING THE OVERNIGHT HOURS.
AS THE UPPER LEVEL LOW APPROACHES THE TEXAS PANHANDLE
OVERNIGHT...A LINE OF STORMS IS EXPECTED TO DEVELOP ALONG THE
PACIFIC FRONT AND SWEEP EAST ACROSS THE REGION. THE LATEST HI-RES
AND SHORT TERM GUIDANCE IS NOW SLOWER WITH THE DEVELOPMENT AND
MOVEMENT OF THIS LINE OF STORMS...THUS MADE MINOR ADJUSTMENTS TO
POPS TOMORROW BASED ON THIS SLOWER TIMING. MOST SHORT-TERM
GUIDANCE HAS THE FRONT/LINE OF STORMS ALONG OUR WESTERN BORDER
AROUND 11Z/5 AM CST...GIVE OR TAKE AN HOUR. THIS WOULD PUT THE
LINE OF STORMS ALONG THE I-35 CORRIDOR AROUND MID MORNING AND THEN
MOVING OUT OF OUR EASTERN COUNTIES AROUND MIDDAY. WITH GOOD
AGREEMENT AMONG MANY OF THE MODELS ON THIS SLOWER
TIMING...CONFIDENCE IS FAIRLY HIGH THAT THE SYSTEM WILL TAKE
SLIGHTLY LONGER TO ARRIVE THAN PREVIOUSLY THOUGHT...ESPECIALLY
WITH THE UPPER LEVEL LOW STILL OUT IN ARIZONA.
WITH LARGE SCALE LIFT SPREADING OVER THE AREA OVERNIGHT AND WARM
AIR ADVECTION INCREASING...ALSO EXPECT SCATTERED SHOWER AND
THUNDERSTORM ACTIVITY TO DEVELOP AHEAD OF THE LINE OF STORMS. LIKE
THE STORMS ALONG THE FRONT...THE STORMS AHEAD OF THE FRONT WILL
ALSO BE ELEVATED ABOVE THE COOLER SURFACE BOUNDARY LAYER.
HOWEVER...IT IS POSSIBLE THAT SOME OF THESE EARLY STORMS COULD
ALSO REACH SEVERE LIMITS...IN PARTICULAR SOUTH OF INTERSTATE 20
WHERE MUCAPE WILL BE HIGHER AND LAPSE RATES STEEPER.
HOWEVER...OVERALL THE INSTABILITY OVERNIGHT IT NOT THAT GREAT AND
THE ENVIRONMENT WILL LIKELY REMAIN CAPPED THROUGH MUCH OF THE
NIGHT.
THE GREATER SEVERE THREAT EXISTS WITH THE LINE OF STORMS DUE TO
SUFFICIENT INSTABILITY /MUCAPE VALUES OVER 500 J/KG /...STRONG WIND
SHEAR...AND BETTER LAPSE RATES. IN THIS PARTICULAR
ENVIRONMENT...LARGE HAIL WILL BE THE MAIN THREAT BUT DAMAGING
WINDS WILL ALSO BE POSSIBLE. CLOSER TO DAYBREAK...OR AROUND 6-7
AM...SOME OF THE MODELS DEVELOP SURFACE BASED CAPE UP TO 1000 J/KG
IN OUR SOUTHWESTERN AND SOUTHERN COUNTIES AS THE WARM FRONT LIFTS
INTO THAT AREA AND DEWPOINTS INCREASE INTO THE LOWER 60S. THE NAM
IS MOST AGGRESSIVE WITH THE SURFACE BASED CAPE BUT THE SITUATION
BEARS A CLOSE WATCH AS SURFACE BASED STORMS WILL POSE A TORNADO
THREAT IN THIS STRONGLY SHEARED ENVIRONMENT. WILL HIGHLIGHT A LOW
TORNADO THREAT THURSDAY MORNING ALONG AND SOUTH OF A LINE FROM
HAMILTON TO FAIRFIELD.
STRONG WEST WINDS WILL OCCUR BEHIND THE FRONT TOMORROW AFTERNOON
WHICH WILL RESULT IN TEMPERATURES RECOVERING INTO THE 60S AND
POSSIBLY LOWER 70S. A COLD FRONT WILL MOVE THROUGH THE REGION
THURSDAY NIGHT/EARLY FRIDAY MORNING. THIS WILL RESULT IN COOLER
TEMPS ON FRIDAY AND FREEZING TEMPS ACROSS MUCH OF THE REGION
FRIDAY NIGHT. ANOTHER SHORTWAVE AND UPPER LEVEL TROUGH WILL SWING
ACROSS THE REGION FRIDAY AND SATURDAY BUT THE MOISTURE WILL BE TOO
SCOURED OUT FOR ANY ADDITIONAL RAIN WITH THIS FEATURE. WE WILL
BRIEFLY WARM UP OVER THE WEEKEND BEFORE ANOTHER UPPER LEVEL SYSTEM
MOVES INTO THE PLAINS AND DRIVES A FRONT THROUGH THE REGION ON
MONDAY. SOUTHERLY RETURN FLOW AHEAD OF THIS SYSTEM MAY RESULT IN
SOME SHOWERS AND STORMS SUNDAY AND SUNDAY NIGHT.
82/JLD
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 42 65 33 54 32 / 70 100 5 5 0
WACO, TX 48 67 35 58 31 / 70 90 5 0 0
PARIS, TX 36 59 32 52 27 / 60 90 10 5 0
DENTON, TX 39 64 29 51 25 / 70 100 5 5 0
MCKINNEY, TX 38 64 30 52 28 / 70 100 5 5 0
DALLAS, TX 43 66 34 54 33 / 70 100 5 5 0
TERRELL, TX 41 64 34 55 30 / 60 100 5 5 0
CORSICANA, TX 46 67 37 59 32 / 60 90 10 5 0
TEMPLE, TX 48 69 36 62 33 / 80 90 5 0 0
MINERAL WELLS, TX 43 66 29 55 28 / 80 70 5 5 0
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
75/
AREA FORECAST DISCUSSION
NWS CORPUS CHRISTI TX
1042 PM CST WED FEB 20 2013
.DISCUSSION...SEE AVIATION DISCUSSION BELOW FOR THE 06Z TAF`S.
&&
.AVIATION...OVERALL THINKING REMAINS THE SAME WITH DRIER MID/UPPER
LEVELS MVG ACROSS THE AREA WHILE SHALLOW LOW LEVEL MOISTURE
REMAINS IN PLACE OVERNIGHT. THIS WILL LEAD TO PREVAILING MVFR
CIGS/VSBY`S AND IFR CIGS/VSBY`S BRIEFLY AT TIMES TOWARD EARLY THU
MORNING. VFR CONDITIONS ARE EXPECTED TO RESUME BY MID MORNING. A
FRONTAL BDRY IS STILL EXPECTED TO MOVE THROUGH S TX FROM THE NW TO
SE ON THU...LEADING TO MOD SLY WINDS TONIGHT SHIFTING TO THE SW
EARLY MORNING TO N BY EARLY AFTERNOON. LLWS IS EXPECTED OVERNIGHT
AS THE LLJ INCREASES TO 45-50KTS AND SFC WINDS DECREASE SLIGHTLY. WIND
SPEEDS ARE EXPECTED TO GRADUALLY DIMINISH THROUGH THU AFTERNOON.
&&
.PREV DISCUSSION... /ISSUED 941 PM CST WED FEB 20 2013/
DISCUSSION...LOWERED POPS A BIT OVER THE SOUTHERN AND WESTERN
AREAS...BUT KEPT THEM PRETTY MUCH THE SAME NORTHEAST AS
CONVERGENCE SHOWERS/STREAMERS STILL SEEM REASONABLE. ADJUSTED
CLOUDS A BIT FOR THIS EVENING. OTHERWISE SAW NO NEED TO MAKE ANY
CHANGES AT THIS TIME. TEMPERATURES ARE LOOKING GOOD AT THIS
TIME...EVEN THE HOURLY TEMPERATURES.
MARINE...DECIDED TO GO WITH A SCA FOR THE NORTHERN BAYS. IT WILL
BE CLOSE...BUT WILL FIT BETTER WITH SURROUNDING OFFICES. RUC13 AND
NAM12 ARE SHOWING WINDS GOING UP TO 20 KNOTS OR MORE OVER THAT
AREA SO WILL BITE ON THAT.
PREV DISCUSSION... /ISSUED 550 PM CST WED FEB 20 2013/
DISCUSSION...SEE AVIATION DISCUSSION BELOW FOR THE 00Z TAF`S.
AVIATION...DRIER MID/UPPER LEVELS WILL FILTER ACROSS S TX THROUGH
TONIGHT...HOWEVER LOW LEVEL MOISTURE WILL REMAIN IN PLACE THROUGH
MUCH OF THE NIGHT AHD OF A COLD FRONT. A SLY LOW LEVEL JET WILL
INCREASE TO 45-50KTS WHICH WILL LEAD TO A STRATUS DECK FLUCTUATING
BETWEEN 800-1500FT. PATCHY FOG IS ALSO POSSIBLE BRIEFLY AHD OF
THE FRONTAL BDRY TOWARD SUNRISE. ALI TO VCT MAY SEE THE VSBY DROP
TO AROUND 1SM AT TIMES. MOD TO STRONG S WINDS WILL CLOCK AROUND TO
THE SW AND W THROUGH EARLY TO MID MORNING BECOMING NW TO N BY LATE
MORNING INTO EARLY AFTERNOON AS THE BDRY MOVS ESE ACROSS THE AREA
ON THU. WINDS ARE EXPECTED TO DECREASE THROUGH THE AFTERNOON.
PREV DISCUSSION... /ISSUED 412 PM CST WED FEB 20 2013/
SHORT TERM (TONIGHT THROUGH THURSDAY NIGHT)...UPPER LEVEL
SHORT WAVE TROUGH WILL DEEPEN AND DEVELOP INTO CLOSED LOW AS IT
DIGS FROM SOUTHERN CA AND ACROSS THE TX PANHANDLE THROUGH THE
PERIOD. AS LOW PRESSURE DEEPENS OVER SOUTHWEST TEXAS...SOUTHEAST
WINDS WILL CONTINUE TO INCREASE ACROSS THE REGION TONIGHT.
ADDITIONALLY...A STRONG LLJ OF 40 TO 50KTS WILL DEVELOP OVER THE
EASTERN TWO THIRDS OF THE REGION THIS EVENING AND MOVE EASTWARD
ACROSS THE COASTAL WATERS TONIGHT. EXPECTING WINDS TO MIX TO THE
SURFACE...AND MODERATE TO STRONG ONSHORE FLOW TO DEVELOP ACROSS
THE WATERS. DUE TO THE ELEVATED WINDS AND WIDESPREAD CLOUD
COVER...KEPT MINIMUM TEMPERATURES ON THE WARMER SIDE TONIGHT.
THURSDAY A FRONTAL BOUNDARY WILL APPROACH FROM THE
NORTHWEST...ENTERING THE REGION BY NOON...AND STALL OFFSHORE
THURSDAY EVENING. DRY AIR WILL MOVE IN BEHIND THE FRONT AND
LOW TEMPERATURES WILL BE MUCH COOLER THAN THE NIGHT BEFORE. AS FOR
POPS...MODELS ARE NOW SHOWING MOST OF THE PRECIPITATION OCCURRING
TO THE NORTHEAST OF THE REGION. DID KEEP CHANCE POPS AROUND THE
VICTORIA CROSSROADS AND SLIGHT CHANCE ACROSS MUCH OF THE
REGION...BUT NOT EXPECTING TO GET MUCH OF ANYTHING WIDESPREAD.
LONG TERM (FRIDAY THROUGH WEDNESDAY)...THE EXTENDED FORECAST HAS
CHANGED LITTLE WITH THE 12Z MODEL RUNS. FRIDAY WILL BEGIN WITH HIGH
PRESSURE SURGING INTO THE REGION WITH DRIER AIR ADVECTING INTO SOUTH
TEXAS. WILL KEEP SLIGHT CHANCE TO LOW END CHANCE OF SHOWERS OVER THE
COASTAL WATERS FRIDAY MORNING WHERE LEFT OVER MOISTURE OVERRUN THE
STALLED FRONTAL BOUNDARY. TEMPERATURES WILL BE WARM DURING THE
AFTERNOON ON FRIDAY WITH THE LACK OF COLD AIR ADVECTION ASSOCIATED
WITH THE SURFACE HIGH PRESSURE. FRIDAY NIGHT INTO SATURDAY MORNING
WILL BE COOL...GENERALLY IN THE 40S AND 50S WITH WINDS BECOMING
LIGHT. THE SURFACE RIDGE IS PULLED EASTWARD AND MOVES AWAY FROM
SOUTH TEXAS WITH A WEAK RETURN FLOW DEVELOPING THROUGH THE WEEKEND.
THERE MAY BE ENOUGH MOISTURE RETURN ACROSS THE REGION FOR ISOLATED
SHOWERS AHEAD OF OUR NEXT BOUNDARY ON SUNDAY. A MID/UPPER LEVEL
TROUGH WILL SWEEP THROUGH THE CENTRAL PLAINS AND DRIVE THE FRONT
THROUGH SOUTH TEXAS MONDAY MORNING. THIS WILL ONCE AGAIN BRING
NORTHERLY WINDS AND DRIER CONDITIONS BACK ACROSS SOUTH TEXAS.
AGAIN...JUST A SLIGHT DROP IN AFTERNOON TEMPERATURES BEHIND THIS
BOUNDARY...WITH COOLER OVERNIGHT LOWS INTO TUESDAY MORNING. ONSHORE
FLOW RESUMES AGAIN TUESDAY INTO WEDNESDAY OF NEXT WEEK. OUR THIRD
FRONTAL BOUNDARY IN LINE WILL BE POSSIBLE IN THE MIDDLE OF THE NEXT
WEEK.
FIRE WEATHER...
A FRONTAL BOUNDARY APPROACHING FROM THE NORTHWEST TOMORROW WILL
BRING STRONG WINDS AND LOW RELATIVE HUMIDITIES TO THE RIO GRANDE
PLAINS AND BRUSH COUNTRY. NORTHWEST WINDS WILL RANGE FROM 15 TO
25 MPH WITH GUSTS UP TO 30 MPH AND MINIMUM RELATIVE HUMIDITY
VALUES WILL FALL BETWEEN 15 TO 20 PERCENT DURING THE AFTERNOON. THIS WILL
CREATE POSSIBLE CRITICAL FIRE WEATHER CONDITIONS FOR THE
AREA...AND A RED FLAG WARNING HAS BEEN ISSUED FOR THURSDAY FROM
9AM TO 3PM.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 68 83 57 78 49 / 20 10 10 10 10
VICTORIA 64 79 50 71 43 / 40 40 10 10 10
LAREDO 65 84 51 79 52 / 10 10 10 0 0
ALICE 67 85 54 78 48 / 10 10 10 10 10
ROCKPORT 68 78 58 72 50 / 30 20 10 20 10
COTULLA 61 79 47 77 46 / 10 10 10 10 0
KINGSVILLE 66 85 53 78 47 / 10 10 10 10 10
NAVY CORPUS 68 81 60 75 54 / 20 10 20 10 10
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...RED FLAG WARNING FROM 9 AM TO 3 PM CST THURSDAY FOR THE
FOLLOWING ZONES: DUVAL...LA SALLE...MCMULLEN...WEBB.
GM...SMALL CRAFT ADVISORY UNTIL 3 PM CST THURSDAY FOR THE FOLLOWING
ZONES: COASTAL WATERS FROM BAFFIN BAY TO PORT ARANSAS OUT
20 NM...COASTAL WATERS FROM PORT ARANSAS TO MATAGORDA SHIP
CHANNEL OUT 20 NM...WATERS FROM BAFFIN BAY TO PORT ARANSAS
FROM 20 TO 60 NM...WATERS FROM PORT ARANSAS TO MATAGORDA
SHIP CHANNEL FROM 20 TO 60 NM.
SMALL CRAFT ADVISORY UNTIL 3 AM CST THURSDAY FOR THE FOLLOWING
ZONES: BAYS AND WATERWAYS FROM BAFFIN BAY TO PORT ARANSAS...
BAYS AND WATERWAYS FROM PORT ARANSAS TO PORT O`CONNOR.
&&
$$
TE/81...AVIATION
AREA FORECAST DISCUSSION
NWS SPOKANE WA
415 PM PST Fri Feb 22 2013
.SYNOPSIS...An upper level trough will move through the Pacific
Northwest tonight and exit the region early Saturday morning. Pacific
Northwest today and tonight. This will result in windy conditions
and moderate snow in the mountains. Mountain snow showers will
likely linger into Saturday afternoon. A short break in the
active weather is expected Saturday night and Sunday, before
the next in a series of frontal systems brings increasing chances
for rain and snow to the region on Monday. This active late winter
weather pattern will continue through the next week.
&&
.DISCUSSION...
Updates to hopefully better address the complex snow level and
resulting accumulation or not of the snow at lower levels. Until
the back edge of cold front passes it appears the more intense
snowfall along and slightly ahead of the front is intense enough
to insulate some of the more sheltered north aspects and edges of
roadways resulting in slush while middle of roads have snow-melt
ponded in them...generally all in the high impact 1900-2500 ft
elevation layer where much of the public live and move about. Once
the back edge of the cold front moves through the air-mass is cold
enough to allow snow levels to fall much closer to just about all
valley floors in the forecast area. Additionally the upper level
winds are blowing about quite robustly at ridge-tops primarily
southeasterly and southerly ahead of the passing cold front and
should make the shift to southwest with the cold front passage and
the surface low associated with it eventually positioned in
vicinity of Southern Alberta near 6Z this evening. As such will
likely make numerous adjustments to the grids that may have
little to no impact on the text based products as this 12 hour
period is so cluttered with changing weather. Will likely utilize
the latest HRRR experimental model in addition to the radar and
satellite to make these adjustments. /Pelatti
&&
.AVIATION...
18Z TAFS: Local radar shows the warm front moving through my
eastern zones at 0930 and will continue to push east through the
remainder of the morning. Low clouds and moderate snow will result
in mountain obscurations the remainder of the afternoon. Further
west Rain and snow showers will continue to form and push east
across the basin and into the eastern highlands through the
afternoon resulting in varying conditions. A cold front will
approach from the west with fropa at KEAT between 23z-01z and
KGEG between 03z-06z. All TAF sites will see a 2-3 hour period of
heavier precipitation and mainly as rain. Conditions are expected
to dry out behind the front. Expect increasing pre-frontal winds
out of the south-southwest through the afternoon with peak winds
with and just behind fropa this afternoon and evening. Sustained
winds of 15-20kts with gusts 25-30kts will be likely at all TAF
sites through at least 12z. /Tobin
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 29 40 25 36 29 39 / 60 20 10 20 30 70
Coeur d`Alene 30 38 26 36 30 38 / 100 30 10 20 30 70
Pullman 31 40 26 39 29 41 / 100 50 20 20 30 70
Lewiston 35 48 31 46 33 48 / 50 50 20 10 10 60
Colville 28 42 24 39 29 40 / 30 20 10 20 50 70
Sandpoint 29 38 25 35 30 36 / 100 50 10 30 40 70
Kellogg 29 37 26 34 28 37 / 100 80 20 30 30 60
Moses Lake 30 50 27 46 32 47 / 10 10 0 10 50 30
Wenatchee 30 47 28 43 31 43 / 10 10 0 10 40 30
Omak 23 40 19 35 25 38 / 10 10 0 10 50 60
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...Winter Storm Warning until 7 PM PST Saturday for Central
Panhandle Mountains.
Wind Advisory until 4 PM PST Saturday for Coeur d`Alene Area-
Idaho Palouse.
Winter Weather Advisory until 7 PM PST Saturday for Lewis and
Southern Nez Perce Counties.
Winter Storm Warning until 10 PM PST this evening for Northern
Panhandle.
WA...Winter Weather Advisory until 10 AM PST Saturday for East Slopes
Northern Cascades.
Wind Advisory until 4 PM PST Saturday for Lower Garfield and
Asotin Counties-Spokane Area-Upper Columbia Basin-
Washington Palouse.
Winter Storm Warning until 10 PM PST this evening for Northeast
Mountains.
Winter Storm Warning until 7 PM PST Saturday for Northeast Blue
Mountains.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
540 PM CST FRI FEB 22 2013
.SHORT TERM...
540 PM CST FRI FEB 22 2013
WILL ALLOW THE WINTER WEATHER ADVISORY FOR CLARK AND TAYLOR COUNTY
TO EXPIRE AT 6 PM. STILL EXPECT SOME LIGHTER SNOW ACROSS TAYLOR
COUNTY OVER THE NEXT HOUR...BUT VISIBILITIES AT KMDZ HAVE BEEN
IMPROVING. CALLS TO CLARK COUNTY SHERIFFS DEPARTMENT SAID THE SNOW
HAD ENDED AT NEILLSVILLE AROUND 4 PM. MODELS SUGGEST STILL SOME
PERIODS OF LIGHT SNOW OR FLURRIES THROUGH THE EVENING HOURS OVER
THOSE AREAS AND EVEN FURTHER SOUTH. HOWEVER ANY ACCUMULATIONS
WILL BE MINOR AS SYSTEM PULLS NORTHEAST.
.LONG TERM...MONDAY NIGHT THROUGH THURSDAY
318 PM CST FRI FEB 22 2013
22.12 MEDIUM RANGE MODELS IN SLIGHTLY BETTER AGREEMENT TODAY
REGARDING THE TRACK OF THE STRONG UPPER LOW MONDAY NIGHT INTO
TUESDAY. THE GFS AND ECMWF BRINGING ACCUMULATING SNOW TO THE
FORECAST AREA WHILE THE GEM TAKES THE LOW WELL SOUTH OF THE FORECAST
AREA. THE GFS AND ECMWF TAKE THE LOW ACROSS CENTRAL ILLINOIS ON
TUESDAY AND INTO LOWER MICHIGAN TUESDAY NIGHT. THE GEM TAKES THE LOW
UP THE OHIO RIVER VALLEY. MEANWHILE...THE NAM OFFERS A VERY SIMILAR
SOLUTION TO THE GEM. UNCERTAINTY REMAINS ON THE TRACK OF THE STORM.
DECIDED TO LEAN TOWARD THE ECMWF AND GFS SINCE THE ECMWF TENDS TO
HAVE A BETTER TRACK RECORD WITH THE SYSTEMS FURTHER OUT IT IN
TIME...INCREASING PRECIPITATION CHANCES ACROSS NORTHEAST IOWA INTO
SOUTHWEST AND CENTRAL WISCONSIN. WILL HAVE TO MAINTAIN A CLOSE WATCH
ON THIS SYSTEM SINCE IT HAS THE POTENTIAL TO PRODUCE SIGNIFICANT
SNOWFALL. CHANCES FOR LIGHT SNOW ARE EXPECTED TO LINGER WEDNESDAY
INTO THURSDAY AS THE LOW PUSHES INTO THE EASTERN GREAT LAKES AND
STALLS.
&&
.AVIATION...TONIGHT AND SATURDAY
540 PM CST FRI FEB 22 2013
SURFACE LOW NOW OVER EAST CENTRAL WISCONSIN WILL CONTINUE TO LIFT
NORTHEAST AWAY FROM THE TAF SITES. CYCLONIC FLOW CONTINUES OVER THE
AREA WITH MVFR CLOUDS ROTATING SOUTHEASTWARD OUT OF CENTRAL
MINNESOTA. SOME LIGHT SNOW ALSO STILL BEING REPORTED IN THESE
CLOUDS. 22.20Z HRRR SHOWS THIS AREA OF LIGHT SNOW TO DIMINISH
SOMEWHAT AS IT ROTATES SOUTHEAST AND THUS HAVE ONLY MENTIONED
FLURRIES AT BOTH SITES THIS EVENING. SOME QUESTION AS TO
VISIBILITIES AND CEILINGS HEIGHTS. BOTH THE HRRR AND NAM BUFKIT
SOUNDINGS SHOWING SOME LOW LEVEL MOISTURE UNDER THE INVERSION AND
EVEN HINTS AT THE POSSIBILITY OF SOME IFR CEILINGS...ESPECIALLY AT
KRST. BASED ON UPSTREAM OBSERVATIONS WILL KEEP LOWER END MVFR
CEILINGS IN THE FORECAST ALONG WITH MVFR VISIBILITIES. CYCLONIC FLOW
DOES WEAKEN LATER SATURDAY AND WILL LIKELY GET A RISE IN THE CEILING
HEIGHTS AND PERHAPS EVEN SOME BREAKS IN THE CLOUDS BEFORE 00Z.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
540 PM CST FRI FEB 22 2013
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...RABERDING
LONG TERM...WETENKAMP
AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1144 AM CST THU FEB 21 2013
.SHORT TERM...TODAY
921 AM CST THU FEB 21 2013
QUICK UPDATE TO THE FORECAST TO ACCOUNT FOR STRATUS DECK THAT HAS
FORMED ACROSS CENTRAL AND EASTERN WISCONSIN THIS MORNING. THIS
HAS NOW PUSHED WEST INTO THE FORECAST AREA...AND 21.12Z NAM AND
21.13Z RAP CAPTURE THE LOW LEVEL SATURATION VERY WELL...BRINGING
IT AROUND THE MISSISSIPPI RIVER IN THE LATE MORNING...THEN ACROSS
MOST OF THE AREA BY EARLY AFTERNOON. THE SATURATION IS OCCURRING
IN THE DENDRITIC GROWTH ZONE GIVEN THE COLD TEMPERATURES THIS
MORNING SO LIGHT SNOW / FLURRIES ARE BEING REPORTED AS WELL. THIS
WILL PERSIST FOR MUCH OF THE LATE MORNING AND AFTERNOON HOURS.
VISIBILITY REDUCTIONS HAVE BEEN AS LOW AS 2 MILES...BUT MAINLY IN
THE 4 TO 6 MILE RANGE.
.LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY
303 AM CST THU FEB 21 2013
21.00Z GFS/ECMWF SHOW A RIDGE OF HIGH PRESSURE DRIFTING ACROSS THE
REGION SATURDAY NIGHT THROUGH SUNDAY FOR A BRIEF DRY/QUIET PERIOD.
LOWS SATURDAY NIGHT ARE EXPECTED TO DROP INTO THE SINGLE
DIGITS/LOWER TEENS ABOVE ZERO WITH HIGHS ON SUNDAY RIGHT AROUND
NORMAL IN THE MIDDLE 20S TO LOWER 30S. ATTENTION THEN TURNS TO THE
NEXT STORM SYSTEM TO AFFECT THE AREA SUNDAY NIGHT THROUGH
WEDNESDAY. THIS SYSTEM LOOKS LIKE IT WILL GIVE THE AREA ANOTHER
SHOT OF LONG DURATION ACCUMULATING SNOW WITH PERHAPS A MIX OF
RAIN/SNOW IN THE SOUTH DURING THE DAY MON/TUE AS SURFACE
TEMPERATURES WARM A DEGREE OR TWO ABOVE THE FREEZING MARK. MODELS
PRETTY CLOSE...BUT STILL A BIT AT ODDS WITH THE EXACT TRACK OF THE
LOW. THIS WILL OF COURSE DETERMINE THE EXACT OUTCOME OF ACCUMULATING
SNOW AMOUNTS...DEFINITELY SOMETHING TO KEEP AN EYE ON.
&&
.AVIATION...THROUGH 18Z FRIDAY
1144 AM CST THU FEB 21 2013
CONDITIONS TO DETERIORATE AT KRST/KLSE TONIGHT AS A WINTER STORM
LIFTS TO THE REGION. THERE WILL BE SOME INITIAL DRY AIR AND
SATURATION ISSUES TO OVERCOME...BUT BY 04Z A BAND OF MODERATE
SNOW WILL IMPACT THE TAF SITES. SNOW RATES WITH THIS BAND LOOK TO
BE BETWEEN 1/2 AND 1 INCH PER HOUR. VISIBILITY AND CEILINGS WILL
RAPIDLY DROP TO LIFR...WITH THE WORST CONDITIONS EXPECTED BETWEEN
06Z AND 13Z FRIDAY. BY FRIDAY MORNING...3 TO 5 INCHES WILL HAVE
ACCUMULATED...HOWEVER SNOW WILL LINGER FOR MUCH OF THE DAY.
ADDITIONAL DAYTIME ACCUMULATIONS OF 2 TO 3 INCHES ARE EXPECTED AND
FLIGHT CONDITIONS WILL REMAIN IN LIFR THROUGH AT LEAST 18Z.
EASTERLY WINDS AROUND 10 KTS WILL PERSIST FOR THE ENTIRE PERIOD.
THE SNOW WILL DIMINISH LATE FRIDAY AFTERNOON LEADING TO SLOWLY
IMPROVING CONDITIONS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
303 AM CST THU FEB 21 2013
WI...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 PM CST
FRIDAY FOR WIZ041-053>055-061.
WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 6 PM CST
FRIDAY FOR WIZ017-029-032>034-042>044.
MN...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 PM CST
FRIDAY FOR MNZ079-086>088-094>096.
IA...WINTER STORM WARNING FROM 6 PM THIS EVENING TO 6 PM CST FRIDAY
FOR IAZ008>010-018-019-029-030.
WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 PM CST FRIDAY
FOR IAZ011.
&&
$$
SHORT TERM...ZT
LONG TERM...DAS
AVIATION...ZT
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
921 AM CST THU FEB 21 2013
.SHORT TERM...TODAY
921 AM CST THU FEB 21 2013
QUICK UPDATE TO THE FORECAST TO ACCOUNT FOR STRATUS DECK THAT HAS
FORMED ACROSS CENTRAL AND EASTERN WISCONSIN THIS MORNING. THIS
HAS NOW PUSHED WEST INTO THE FORECAST AREA...AND 21.12Z NAM AND
21.13Z RAP CAPTURE THE LOW LEVEL SATURATION VERY WELL...BRINGING
IT AROUND THE MISSISSIPPI RIVER IN THE LATE MORNING...THEN ACROSS
MOST OF THE AREA BY EARLY AFTERNOON. THE SATURATION IS OCCURRING
IN THE DENDRITIC GROWTH ZONE GIVEN THE COLD TEMPERATURES THIS
MORNING SO LIGHT SNOW / FLURRIES ARE BEING REPORTED AS WELL. THIS
WILL PERSIST FOR MUCH OF THE LATE MORNING AND AFTERNOON HOURS.
VISIBILITY REDUCTIONS HAVE BEEN AS LOW AS 2 MILES...BUT MAINLY IN
THE 4 TO 6 MILE RANGE.
.LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY
303 AM CST THU FEB 21 2013
21.00Z GFS/ECMWF SHOW A RIDGE OF HIGH PRESSURE DRIFTING ACROSS THE
REGION SATURDAY NIGHT THROUGH SUNDAY FOR A BRIEF DRY/QUIET PERIOD.
LOWS SATURDAY NIGHT ARE EXPECTED TO DROP INTO THE SINGLE
DIGITS/LOWER TEENS ABOVE ZERO WITH HIGHS ON SUNDAY RIGHT AROUND
NORMAL IN THE MIDDLE 20S TO LOWER 30S. ATTENTION THEN TURNS TO THE
NEXT STORM SYSTEM TO AFFECT THE AREA SUNDAY NIGHT THROUGH
WEDNESDAY. THIS SYSTEM LOOKS LIKE IT WILL GIVE THE AREA ANOTHER
SHOT OF LONG DURATION ACCUMULATING SNOW WITH PERHAPS A MIX OF
RAIN/SNOW IN THE SOUTH DURING THE DAY MON/TUE AS SURFACE
TEMPERATURES WARM A DEGREE OR TWO ABOVE THE FREEZING MARK. MODELS
PRETTY CLOSE...BUT STILL A BIT AT ODDS WITH THE EXACT TRACK OF THE
LOW. THIS WILL OF COURSE DETERMINE THE EXACT OUTCOME OF ACCUMULATING
SNOW AMOUNTS...DEFINITELY SOMETHING TO KEEP AN EYE ON.
&&
.AVIATION...TODAY AND TONIGHT
515 AM CST THU FEB 21 2013
VFR CONDITIONS WILL PREVAIL THROUGH THE LATE AFTERNOON AS HIGH
PRESSURE SLOWLY DRIFTS AWAY FROM THE REGION. A WINTER STORM
ADVANCING NORTHEAST OUT OF THE SOUTHERN PLAINS STATES WILL BRING A
ROUND OF SNOW TO THE AREA TONIGHT. PLENTY OF FORCING WITH THIS
SYSTEM WITH THE 21.06Z NAM SHOWING UP TO 30 PVU/S OF VORTICITY
ADVECTION IN THE 500-300 MB LAYER AND A COUPLE BANDS OF WEAK TO
MODERATE FRONTOGENESIS IN THE 850-500 MB LAYER. THE HIGH PRESSURE
WILL LEAVE PLENTY OF DRY AIR IN PLACE WITH CONDENSATION PRESSURE
DEFICITS OF 200+ MB ON THE 280K ISENTROPIC SURFACE. THE INITIAL UP
GLIDE OF 2 TO 5 UBAR/S WILL GO INTO SATURATING THIS DRY LAYER WITH
TOTAL SATURATION EXPECTED TO OCCUR AT THE TAF SITES BETWEEN 22.03Z
AND 22.06Z. INTERESTING TO NOTE THAT THE NAM BUFKIT SOUNDINGS FOR
BOTH SITES SHOWS A MVFR DECK DEVELOPING EARLY IN THE EVENING AS
THE DRY AIR BECOMES CONFINED TO THE 900-700 MB LAYER. LOOKING DOWN
STREAM INTO KANSAS...THERE IS A MVFR DECK WELL OUT AHEAD OF THE
MAIN PRECIPITATION SHIELD SO HAVE INCLUDED THIS. EXPECTING LIGHT
SNOW WITH MVFR VISIBILITIES TO DEVELOP DURING THE MID EVENING AND
ONCE THE COLUMN TOTALLY SATURATES UP...THE VISIBILITY AND CEILINGS
WILL GO DOWN TO IFR AND THEN STAY THERE OVERNIGHT.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
303 AM CST THU FEB 21 2013
WI...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 PM CST
FRIDAY FOR WIZ041-053>055-061.
WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 6 PM CST
FRIDAY FOR WIZ017-029-032>034-042>044.
MN...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 PM CST
FRIDAY FOR MNZ079-086>088-094>096.
IA...WINTER STORM WARNING FROM 6 PM THIS EVENING TO 6 PM CST FRIDAY
FOR IAZ008>010-018-019-029-030.
WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 PM CST FRIDAY
FOR IAZ011.
&&
$$
SHORT TERM...ZT
LONG TERM...DAS
AVIATION...04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1132 PM CST WED FEB 20 2013
.SHORT TERM...TONIGHT THROUGH SATURDAY
232 PM CST WED FEB 20 2013
FORECAST CONCERNS ARE ON WINTER STORM IMPACTING THE AREA THURSDAY
NIGHT INTO FRIDAY.
LATEST WATER VAPOR IMAGERY AND 500 MB RAP ANALYSIS SHOWED A COMPLEX
PATTERN ACROSS THE CONUS TODAY. AN UPPER LOW WAS LOCATED OVER NEW
ENGLAND WHILE ANOTHER WAS MOVING INTO SOUTHERN CALIFORNIA. AN UPPER
RIDGE EXTENDED FROM THE MID MISSISSIPPI RIVER VALLEY NORTH THROUGH
THE UPPER MIDWEST.
THE UPPER LOW OVER SOUTHERN CALIFORNIA WILL BE THE MAIN FEATURE TO
WATCH CLOSELY TONIGHT AS IT MOVES THROUGH ARIZONA AND NEW MEXICO
OVERNIGHT...EJECTING INTO THE CENTRAL PLAINS ON THURSDAY. THE LOW
WILL LIFT NORTHEAST THROUGH SOUTHEAST NEBRASKA EARLY FRIDAY EVENING.
AHEAD OF THE APPROACHING LOW...STRONG ISENTROPIC LIFT WILL MOVE
MOVE INTO THE FORECAST AREA ON THE 280-310 K SURFACES DURING THE
EVENING HOURS ON THURSDAY LEADING TO THE DEVELOPMENT OF SNOW.
IMPRESSIVE LIFT NOTED IN THE DENDRITIC GROWTH ZONE THURSDAY
EVENING INTO LATE THURSDAY NIGHT...WITH LIFT OF -20 UBAR/S NOTED
AT -15C. THE ONLY NEGATIVE WITH THIS SYSTEM IS THAT THE
INGREDIENTS FOR HEAVY SNOW FALL ADVECT NORTHEAST THROUGH THE
FORECAST AREA VERY QUICKLY DURING THE OVERNIGHT HOURS.
HOWEVER...MOST ARES WILL SEE A PERIOD OF HEAVY SNOWFALL WITH
ACCUMULATION RATES OF 1 TO 1.5 INCHES PER HOUR. SNOW ACCUMULATIONS
BY 12Z FRIDAY ARE EXPECTED TO RANGE FROM 5 TO 7 INCHES ACROSS MUCH
OF NORTHEAST IOWA. LOCATIONS OVER SOUTHEAST MINNESOTA AND
SOUTHWEST THROUGH CENTRAL WISCONSIN ARE EXPECTED TO SEE SNOW
ACCUMULATIONS OF 3 TO 6 INCHES. THE BULK OF THE SNOW WILL FALL
DURING THE OVERNIGHT HOURS THROUGH THE FRIDAY MORNING
COMMUTE...LEADING TO TRAVEL IMPACTS. HAVE ISSUED A WINTER STORM
WARNING FOR MOST OF NORTHEAST IOWA...EXCLUDING ALLAMAKEE
COUNTY...AND HAVE ISSUED A WINTER WEATHER ADVISORY FOR THE REST OF
THE FORECAST AREA. SEE WATCH/WARNING/ADVISORIES SECTIONS BELOW FOR
SPECIFIC TIMING. SNOWFALL AMOUNTS HAVE TRENDED SLIGHTLY LESS IN
THE 12Z GUIDANCE AND THIS MAKES SENSE GIVEN THE PROGRESSIVE NATURE
OF THE HEAVY SNOWFALL INGREDIENTS. THE LOW WILL LIFT NORTHEAST
DURING THE DAY ON FRIDAY AND IS EXPECTED TO BE LOCATED OVER SOUTH
CENTRAL MINNESOTA BY MIDDAY FRIDAY. LIGHT SNOW LOOKS TO PERSIST
INTO FRIDAY AFTERNOON WITH ADDITIONAL ACCUMULATIONS OF 1 TO 2
INCHES POSSIBLE. THE SNOW WILL TAPER OFF SOUTH AND WEST OF
INTERSTATE 94 THROUGH THE AFTERNOON HOURS AND PERSIST NORTH OF
I-94 INTO FRIDAY EVENING. WILL HAVE TO KEEP A CLOSE EYE ON
FREEZING DRIZZLE POTENTIAL OVER SOUTHWEST INTO CENTRAL WISCONSIN
AS ICE IS LOST ALOFT LATE FRIDAY MORNING INTO EARLY FRIDAY
AFTERNOON. OTHERWISE...HIGH PRESSURE WILL BE IN CONTROL TONIGHT
INTO THURSDAY MORNING PROVIDING COOL AND QUIET CONDITIONS. HIGH
CLOUDS WILL BE ON THE INCREASE FROM THE SOUTHWEST AHEAD OF THE
APPROACHING SYSTEM. LOOK FOR LOWS TONIGHT TO RANGE FROM THE SINGLE
DIGITS BELOW ZERO ACROSS NORTH CENTRAL WISCONSIN TO THE SINGLE
DIGITS ABOVE ZERO OVER NORTHEAST IOWA.
THE LOW WILL LIFT INTO UPPER MICHIGAN EARLY ON SATURDAY AS WEAK HIGH
PRESSURE BUILDS INTO THE FORECAST AREA. MOSTLY CLOUDY SKIES ARE
EXPECTED ACROSS THE FORECAST AREA ON SATURDAY UNDER THE INFLUENCE OF
WEAK CYCLONIC FLOW IN THE WAKE OF THE DEPARTING LOW. LIGHT SNOW
COULD LINGER ACROSS NORTH CENTRAL WISCONSIN DURING THE DAY. HIGHS ON
SATURDAY WILL RANGE FROM THE MID 20S OVER CENTRAL WISCONSIN TO THE
LOWER 20S OVER SOUTHEAST MINNESOTA. A VIGOROUS TROUGH WILL MOVE
THROUGH THE PACIFIC NORTHWEST ON SATURDAY...DIVING INTO THE CENTRAL
ROCKIES SATURDAY NIGHT. THIS SYSTEM IS THE NEXT FEATURE TO KEEP A
CLOSE EYE ON.
.LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY
232 PM CST WED FEB 20 2013
20.12 MEDIUM RANGE MODELS ARE IN REASONABLE SATURDAY NIGHT THROUGH
SUNDAY SHOWING THE TROUGH PUSHING INTO THE CENTRAL ROCKIES BY SUNDAY
AFTERNOON. MEANWHILE...RIDGING WILL BUILD OVER THE UPPER MISSISSIPPI
RIVER VALLEY PROVIDING PARTLY SUNNY SKIES ON SUNDAY. HIGHS ON SUNDAY
ARE EXPECTED TO RANGE FROM THE LOWER 30S OVER CENTRAL WISCONSIN TO
THE UPPER 20S OVER NORTHEAST IOWA. THE TROUGH IS EXPECTED TO MOVE
EAST OUT OF THE ROCKIES AND INTO THE CENTRAL PLAINS AND DEEPENING
INTO A STRONG UPPER LOW. MODEL SOLUTIONS START TO DIVERGE SLIGHTLY
MONDAY INTO TUESDAY. THE 20.00 ECMWF TAKES THE LOW ACROSS EASTERN
KANSAS THROUGH NORTHERN MISSOURI MONDAY NIGHT AND INTO NORTHERN
ILLINOIS BY EARLY TUESDAY MORNING. THE GFS HAS A SLIGHTLY MORE
NORTHERLY TRACK. THIS SYSTEM WILL BRING WARMER AIR WITH IT AND THE
POTENTIAL FOR A RAIN AND SNOW MIX. THIS SYSTEM HAS THE POTENTIAL
TO BRING SIGNIFICANT SNOWFALL TO THE REGION BUT THE EXACT TRACK IS
UNCERTAIN AND WILL BE PINNED DOWN OVER THE NEXT FEW MODEL RUNS.
THE 20.00 ECMWF LIFTS THE LOW NORTH INTO EASTERN UPPER MICHIGAN BY
WEDNESDAY MORNING WHILE THE GFS TAKES IT TO THE EAST INTO THE OHIO
RIVER VALLEY. LIGHT SNOW CHANCES WILL CONTINUE TUESDAY INTO
WEDNESDAY...DEPENDING ON THE LOW TRACK.
&&
.AVIATION...THROUGH 06Z FRIDAY
1132 PM CST WED FEB 20 2013
VFR CONDITIONS WITH HIGH CLOUDS EXPECTED THROUGH 00Z FRIDAY WITH
WINDS GRADUALLY COMING AROUND TO THE EAST BUT REMAINING UNDER 10
KNOTS. BETWEEN 00Z-06Z SURFACE LOW BEGINS TO PUSH NORTHWARD OUT
OF THE CENTRAL PLAINS. QUESTION WILL BE ONSET OF SNOW AS SOUNDINGS
SHOW QUITE A BIT OF MID AND LOW LEVEL DRY AIR TO OVERCOME. MODELS
CONSISTENT IN SHOWING SNOW TO BREAK OUT BETWEEN 02Z-04Z AT BOTH
TAF SITES. ONCE THE SNOW BEGINS VISIBILITIES WILL QUICKLY LOWER
INTO THE IFR CATEGORY WITH CEILINGS LOWERING INTO THE IFR TO LOWER
MVFR CATEGORY.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
232 PM CST WED FEB 20 2013
WI...WINTER WEATHER ADVISORY FROM 6 PM THURSDAY TO 6 PM CST FRIDAY
FOR WIZ041-053>055-061.
WINTER WEATHER ADVISORY FROM MIDNIGHT THURSDAY NIGHT TO 6 PM CST
FRIDAY FOR WIZ017-029-032>034-042>044.
MN...WINTER WEATHER ADVISORY FROM 6 PM THURSDAY TO 6 PM CST FRIDAY
FOR MNZ079-086>088-094>096.
IA...WINTER STORM WARNING FROM 6 PM THURSDAY TO 6 PM CST FRIDAY FOR
IAZ008>010-018-019-029-030.
WINTER WEATHER ADVISORY FROM 6 PM THURSDAY TO 6 PM CST FRIDAY
FOR IAZ011.
&&
$$
SHORT TERM...WETENKAMP
LONG TERM...WETENKAMP
AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
1259 AM EST SAT FEB 23 2013
.SYNOPSIS...
A WARM FRONT IS EXPECTED TO LIFT NORTHWARD INTO SOUTHEAST GEORGIA
THROUGH TONIGHT AS A WEDGE OF HIGH PRESSURE ANCHORS OVER THE
CAROLINAS. A WAVE OF LOW PRESSURE WILL DEVELOP ALONG THE FRONT ON
SATURDAY THEN PUSH NORTHEAST. HIGH PRESSURE WILL BRIEFLY RETURN TO
THE AREA ON SUNDAY BEFORE A WARM FRONT LIFTS NORTH ACROSS THE AREA
LATE MONDAY AND MONDAY NIGHT....FOLLOWED BY THE PASSAGE OF A COLD
FRONT EARLY TUESDAY. DRIER CONDITIONS ARE EXPECTED TO RETURN TO THE
REGION BY THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
SHORTLY AFTER MIDNIGHT...RAIN IS WIDESPREAD OVER THE FORECAST AREA
BUT FOG PROBLEMS WERE MAINLY CONFINED TO SOME OF THE NEAR SHORE
COASTAL WATERS AND PERHAPS BEACHES FROM SAVANNAH TO CHARLESTON.
RAINY WEATHER WILL CONTINUE OVERNIGHT WITH SOME POCKETS OF HEAVIER
DOWNPOURS AT TIMES.
TEMPERATURES...PINNING DOWN TEMPERATURES REMAINS EXTREMELY
DIFFICULT. THE LATEST RAP SUGGESTS THE WEDGE FRONT WILL REMAIN
QUASI-STATIONARY OVER THE NEXT FEW HOURS...POSSIBLY EMERGING OFF
THE LOWER SOUTH CAROLINA COAST BY DAYBREAK. WINDS REMAINED NORTH
AT THE CHARLESTON AIRPORT WHICH AGREES WELL WITH THE RAP WIND
FIELDS. HAVE ADJUSTED HOURLY TEMPERATURES TO BETTER MATCH THE
REPOSITIONING OF THE WEDGE FRONT THROUGH SUNRISE. ALSO LOWERED LOW
TEMPERATURES DOWN QUITE A BIT IN SOME AREAS AS SOME LOCALES WELL
INLAND WERE ALREADY BELOW FORECASTED MINIMUMS. COULD VERY WELL SEE
A HUGE SWING IN TEMPERATURES...ESPECIALLY AT THE COAST...SHOULD
THE WARM FRONT PUSHING BACK INLAND QUICKER THAN EXPECTED. LOWS
WILL RANGE FROM THE LOWER 40S WELL INLAND TO AROUND 60 IN THE
LUDOWICI- DARIEN- HINESVILLE CORRIDOR...BUT THIS IS A HIGHLY
UNCERTAIN FORECAST.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH MONDAY/...
SATURDAY AND SATURDAY NIGHT...A VERY LOW CONFIDENCE FORECAST TO
START THE WEEKEND. A WEDGE FRONT WILL LIKELY BE POSITIONED SOMEWHERE
ACROSS NORTHWEST PORTIONS OF THE FORECAST AREA AT THE START OF THE
DAY AS A WAVE OF LOW PRESSURE DEVELOPS IN THE VICINITY OF CENTRAL
GEORGIA. THE LOW WILL TRACK ALONG THE WEDGE FRONT THROUGH THE DAY
AND SHIFT NORTHEAST OF THE AREA IN THE EVENING AS A TRAILING COLD
FRONT SWINGS THROUGH FROM THE NORTHWEST.
SHOWERS ARE EXPECTED TO BE ONGOING IN THE MORNING ACROSS NORTHWEST
PORTIONS OF THE AREA...WITH THE GREATEST COVERAGE TOWARD THE
MIDLANDS AND EAST-CENTRAL GEORGIA...AS A DISTURBANCE APPROACHES
ALOFT AND ISENTROPIC LIFT STRENGTHENS. SOME SHOWERS SHOULD ALSO BE
STREAMING INTO COASTAL SOUTH CAROLINA FROM THE ADJACENT COASTAL
WATERS. THE BAND OF SHOWERS OVER THE MIDLANDS AND EAST-CENTRAL
GEORGIA SHOULD SHIFT SOUTHEAST OVER THE AREA DURING THE AFTERNOON
AND EARLY EVENING AS THE WAVE OF LOW PRESSURE PASSES...EVENTUALLY
TAPERING OFF OVERNIGHT AS THE TRAILING COLD FRONT PUSHES OFFSHORE.
WITH PRECIPITABLE WATER VALUES AROUND 1.5 INCHES...OR NEARLY 2
STANDARD DEVIATIONS ABOVE NORMAL...THE RAIN COULD BE HEAVY AT TIMES.
THERE IS A POTENTIAL FOR SOME ISOLATED THUNDERSTORMS MAINLY IN THE
AFTERNOON IN THE WARM SECTOR...WHICH SHOULD BE OVER PARTS OF
SOUTHEAST GEORGIA AND COASTAL SOUTHEAST SOUTH CAROLINA.
TEMPERATURES WILL BE VERY DIFFICULT TO FORECAST...WITH A VERY LARGE
GRADIENT EXPECTED OVER THE AREA. WITH THE WEDGE EXPECTED TO PERSIST
ACROSS FAR NORTHWEST PORTIONS OF THE AREA HIGHS THERE ARE ONLY
FORECAST TO BE IN THE LOWER 50S...BUT WITHIN THE WARM SECTOR HIGHS
COULD BE IN THE LOWER TO MID 70S ACROSS NORTH COASTAL GEORGIA AND
AREAS CLOSER TO THE ALTAMAHA. PINNING DOWN THE EXACT POSITION OF THE
WEDGE IS SO DIFFICULT THAT TEMPERATURES IN SOME AREAS COULD BE OFF
BY AS MUCH AS 10 DEGREES FROM THE CURRENT FORECAST.
SUNDAY...HIGH PRESSURE WILL BRIEFLY BUILD OVER THE REGION FROM THE
NORTHWEST WITH RAIN-FREE CONDITIONS EXPECTED. TEMPERATURES COULD
REACH HIGHS AROUND 70 WITH A DOWNSLOPE WIND COMPONENT ALOFT UNDER
MOSTLY SUNNY TO PARTLY CLOUDY SKIES.
SUNDAY NIGHT AND MONDAY...A WARM FRONT EXTENDING FROM A STORM SYSTEM
OVER THE MID-MISSISSIPPI VALLEY WILL SLOWLY LIFT NORTHWARD TOWARD
THE AREA. IT APPEARS THE WARM FRONT COULD ENTER PARTS OF SOUTHEAST
GEORGIA LATE IN THE DAY ON MONDAY. STRENGTHENING ISENTROPIC ASCENT
AND DEEP MOISTURE AHEAD OF THE WARM FRONT SHOULD ALLOW SCATTERED TO
NUMEROUS SHOWERS TO DEVELOP FROM THE SOUTH SUNDAY NIGHT...THEN
BECOME NUMEROUS TO WIDESPREAD ACROSS THE AREA ON MONDAY. SOME
ISOLATED THUNDERSTORMS COULD ALSO DEVELOP ACROSS SOUTHERN AREAS
LATER IN THE DAY DEPENDING ON THE TIMING OF THE FRONT.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
WET CONDITIONS WILL PERSIST OVER THE FORECAST AREA THROUGH EARLY
NEXT WEEK AS A SFC LOW SHIFTS ACROSS THE SOUTHEAST. CONDITIONS WILL
THEN BEGIN TO DRY AS THE SFC LOW SHIFTS OFF THE MID ATLANTIC COAST
AND IS FOLLOWED BY HIGH PRESSURE OVER THE SOUTHEAST. A COOL AND DRY
TREND SHOULD THEN TAKE PLACE THROUGH MUCH OF NEXT WEEK AS A
MID/UPPER LVL LOW BECOMES CUT OFF OVER THE NORTHEASTERN UNITED
STATE. OVERALL...AFTERNOON HIGHS WILL RANGE FROM THE MID 60S ON
TUESDAY TO THE UPPER 50S BY THURSDAY. OVERNIGHT LOWS WILL RANGE FROM
THE UPPER 30S/LOWER 40S ON TUESDAY TO MID 30S/LOWER 40S BY THURSDAY.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
BOTH TERMINALS WILL BE IFR OR LOWER FOR MOST OF THE NIGHT AS MORE
DEEP MOISTURE AND WIDESPREAD RAINFALL CONTINUE TO TRACK UP THE
COAST. DEGRADED VISIBILITIES DUE TO FOG AND RAIN ARE ALSO A
POSSIBILITY AS THE WARM FRONT AND MINOR SHORTWAVE IMPULSES MOVE UP
INTO THE AREA. CONDITIONS LOOK TO SLIGHTLY IMPROVE BY DAYBREAK AS
THE WARM FRONT LIFTS NORTH OF KSAV AND WIND SPEEDS PICK
UP...HOWEVER...MODEL SOUNDINGS ARE KEEPING THE DEEP MOISTURE IN
PLACE FOR THE DAY. FORECAST SOUNDINGS FOR THIS AFTERNOON AND EVENING
INDICATE CIGS WILL LOWER IF THEY EVEN MANAGE TO IMPROVE TO MVFR
FOR A SHORT PERIOD.
EXTENDED AVIATION OUTLOOK...IFR CONDITIONS WILL LIKELY CONTINUE
OVERNIGHT SATURDAY NIGHT DUE TO LOW CEILINGS AND REDUCED
VISIBILITIES BUT BEGIN TO SHOW LATE NIGHT IMPROVEMENTS AS DRIER
AIR FILLS IN BEHIND A COLD FRONT PASSAGE. VFR CONDITIONS WILL PREVAIL
SUNDAY...THEN MVFR OR LOWER CONDITIONS SHOULD RETURN SUNDAY NIGHT
THROUGH MONDAY NIGHT. VFR CONDITIONS WILL THEN PREVAIL TUESDAY
INTO WEDNESDAY.
&&
.MARINE...
SAVANNAH PILOT BOAT REPORTED VSBYS NEAR ZERO IN DENSE SEA FOG AS
FAR OFFSHORE AS BUOY CHARLIE. HILTON HEAD AIRPORT ALSO REPORTING A
CEILING NEAR 100 FT SUGGESTING FOG IS LIKELY NOT TOO FAR OFFSHORE.
HAVE ISSUED A DENSE FOG ADVISORY FOR AMZ352-354 UNTIL 1 AM. ITS
UNCLEAR HOW MUCH VSBYS WILL IMPROVE AS RAIN FILLS IN...SO ONLY
TOOK THE ADVISORY UNTIL 1 AM. ADJUSTMENTS WILL BE NEEDED OVER THE
NEXT FEW HRS. ADJUSTED WINDS OVER THE SOUTH CAROLINA WATERS TO
NORTH OVERNIGHT AS RAP GUIDANCE SUGGESTS THE WEDGE FRONT WILL DROP
SOUTH. ALSO NUDGED THE START TIME FOR THE SMALL CRAFT ADVISORY TO
THE CURRENT TIME OVER THE GEORGIA OFFSHORE WATERS.
SATURDAY THROUGH TUESDAY...SMALL CRAFT ADVISORY CONDITIONS WILL
PERSIST OVER OUTER GEORGIA WATERS THROUGH 5 PM SATURDAY AS A WEDGE
OF HIGH PRESSURE INLAND MAINTAINS AN ENHANCED PRESSURE GRADIENT OVER
THESE WATERS THROUGH MUCH OF THE DAY AND SEAS REMAIN ELEVATED. THE
WEDGE WILL THEN BREAK DOWN LATE AS A SFC LOW TRACKS THROUGH THE
SOUTHEASTERN UNITED STATES AND INTO THE MID ATLANTIC. EXPECT
SOUTHERLY WINDS TO BECOME WEST AS A TRAILING COLD FRONT SHIFTS
THROUGH THE WATERS INTO EARLY SUNDAY. CONDITIONS WILL THEN REMAIN
BELOW SMALL CRAFT ADVISORY LEVELS FOR ALL WATERS THROUGH EARLY
MONDAY AS HIGH PRESSURE DOMINANTS THE PATTERN. WINDS AND SEAS WILL
THEN INCREASE MONDAY AFTERNOON INTO TUESDAY AS A WARM FRONT LIFTS
NORTH AND THEN IS FOLLOWED BY A SFC LOW TRACKING OVER THE WATERS
LATE. WE COULD SEE SMALL CRAFT ADVISORY CONDITIONS AS THE PRESSURE
GRADIENT BECOMES ENHANCED OVER THE WATERS DURING THIS TIME.
&&
.HYDROLOGY...
STORM TOTAL RAINFALL AMOUNTS OF 3-6 INCHES WITH LOCALLY HIGHER
AMOUNTS ARE LIKELY TO OCCUR ACROSS THE REGION THROUGH EARLY NEXT
WEEK BRINGING MORE RELIEF TO DROUGHT STRICKEN AREAS. THESE RAINS
FALLING INTO ALREADY SWOLLEN RIVERS WILL YIELD ADDITIONAL RISES
AND RIVER FLOODING THROUGH THE END OF NEXT WEEK. ADDITIONAL RIVER
FLOOD WARNINGS ARE LIKELY PER THE LATEST SHORT TERM ENSEMBLE
HYDROLOGIC FORECASTS AND RIVER GUIDANCE FROM THE SOUTHEAST RIVER
FORECAST CENTER.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...DENSE FOG ADVISORY UNTIL 5 AM EST EARLY THIS MORNING FOR
AMZ330-350-352-354.
SMALL CRAFT ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR AMZ374.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...JAQ
LONG TERM...DPB
AVIATION...
MARINE...ST
HYDROLOGY...
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1041 AM CST THU FEB 21 2013
.DISCUSSION...
ISSUED 1024 AM CST THU FEB 21 2013
WINTER WEATHER STORM SPINNING UP OVER MISSOURI AND ON TRACK FOR
ILX THIS AFTERNOON. SOME MINOR MIX OF PRECIPITATION ON THE LEADING
EDGE...BUT MAINLY SNOW EXPECTED WEST AND NORTHWEST OF THE I-55
CORRIDOR. FREEZING RAIN STILL ANTICIPATED ON THE BACK EDGE OF THE
SYSTEM...AND IN THE SOUTHEAST...PARTICULARLY ALONG AND SOUTH OF A
LINE ROUGHLY FROM PARIS TO TAYLORVILLE. GOING FORECAST IS ACTUALLY
ON TRACK...AND CONSIDERING THE WINTRY MIX AND CURRENT
VARIABLES...NO REASON TO ALTER THE FORECAST BEYOND WHAT IS
CURRENTLY IN THE GRIDS SIGNIFICANTLY. HAVE ALTERED HOURLY TEMPS
AND SKY COVER...BUT PRECIP TRENDS ON TRACK. MAJOR CONCERN FOR
AFFECTING THE SNOW TOTAL AMOUNTS ARE TWO FOLD...ONE...THE SYSTEM
WILL LIKELY BE QUICK IN PASSING AND TOTALS WILL HAVE TO
ACCUMULATE QUICKLY TO MAKE AN IMPACT BEFORE THE AREA IS OVERTAKEN
BY THE DRY SLOT. TWO...THOUGH THUNDER ACTIVITY IS EXPECTED TO
REDUCE AS THE SYSTEM PULLS THROUGH CENTRAL IL...SOME ISOLATED
THUNDER IS STILL QUITE POSSIBLE. AREAS AFFECTED BY A CONVECTIVELY
ENHANCED STORM HAVE THE POTENTIAL TO SEE LOCALIZED HIGHER TOTALS.
WINTER WEATHER ADVISORIES AND TIMING REMAIN UNCHANGED.
HJS
&&
.AVIATION...
ISSUED 532 AM CST THU FEB 21 2013
LARGE STRATOCUMULUS DECK AROUND 2000 FEET IS ADVECTING IN FROM THE
NORTHEAST...WITH AWIPS TIMING TOOLS INDICATING ARRIVAL FROM KBMI-
KCMI BY AROUND 13Z. RAP MODEL HUMIDITY PLOT AT 2500 FEET LINES UP
WELL...AND SUGGESTS IT SHOULD CONTINUE TOWARD KPIA AND KDEC TOWARD
16-17Z. WILL KEEP THESE MVFR CEILINGS OUT OF KSPI FOR NOW...BUT
CONDITIONS THERE WILL RAPIDLY DETERIORATE EARLY THIS AFTERNOON
WITH SNOW MOVING IN FROM THE SOUTHWEST TOWARD 21Z. THIS
PRECIPITATION WILL OVERSPREAD THE REMAINING TAF SITES BY ABOUT
23Z...WITH IFR OR LIFR CONDITIONS BECOMING WIDESPREAD. FORECAST
SOUNDINGS SHOWING SOME FREEZING RAIN POTENTIAL AT KSPI/KDEC EARLY
THIS EVENING AS WELL. HEAVIEST PRECIPITATION EXPECTED THROUGH
ABOUT 04-05Z...WITH A GRADUAL TREND TOWARD FREEZING DRIZZLE AT ALL
TAF SITES AFTER 06Z.
GEELHART
&&
.PREV DISCUSSION...
ISSUED 340 AM CST THU FEB 21 2013
WILL CONTINUE THE WINTER WEATHER ADVISORY ACROSS CENTRAL AND
SOUTHEAST IL BUT START IT AT NOON IN AREAS FROM SPRINGFIELD SW
AND START AT 3 PM REST OF CWA. WINTER WX ADVISORY GOES THROUGH 6
AM FRIDAY EXCEPT THROUGH NOON FRIDAY FROM LINCOLN NORTH. INCREASED
ICE ACCUMULATIONS OVER SE IL TO BETWEEN A TENTH AND A QUARTER INCH
AND ALSO ADDED ISOLATED THUNDERSTORMS TO SW AREAS LATE TODAY.
BRUNT OF SNOW STILL EXPECTED TO DEVELOP FROM SW TO NE DURING THE
AFTERNOON AND CONTINUE THIS EVENING BEFORE DIMINISHING OVERNIGHT.
SNOWFALL AMOUNTS TO RANGE FROM LESS THAN 1 INCH FROM I-70 SE TO
3-5 INCHES FROM I-55 NW WITH HIGHEST AMOUNTS NW OF THE IL RIVER.
BETWEEN 1 AND 3 INCHES OF SNOW OVER EAST CENTRAL IL WITH ICE
ACCUMULATIONS UP TO A TENTH INCH AS FAR NORTH AS I-72.
SHORT TERM...TODAY THROUGH SUNDAY
STRONG 541 DM 500 MB LOW NEAR THE SOUTHERN AZ/NM BORDER THAT
BROUGHT SNOW AS FAR SOUTH AS TUCSON IN SOUTHERN AZ THIS PAST NIGHT
HAS 996 MB LOW PRESSURE OVER NE NM. 1042 DM 500 MB ARCTIC HIGH
PRESSURE OVER NW ONTARIO AND RIDGING SOUTHWARD INTO IL AND TN VALLEY
BRINGING ANOTHER COLD NIGHT WITH TEMPS IN THE MID TO UPPER TEENS
CENTRAL IL AND LOWER 20S IN SE IL.
MODELS EJECT UPPER LEVEL LOW NE INTO THE CENTRAL PLAINS BY THIS
EVENING AND INTO WI FRI EVENING. STRONG SURFACE LOW IN NE NM TO
WEAKEN AS IT EJECTS NE INTO SE KS BY THIS EVENING AND INTO NW IL
BY MIDDAY FRI. MODELS HAVE TRENDED FURTHER SE WITH LOW PRESSURE
TRACK AND ALSO WITH COLDER AIR. MODELS IN GOOD AGREEMENT THAT MOST
OF CENTRAL/SE IL WILL STAY DRY THIS MORNING WITH SNOW SPREADING NE
ACROSS AREA DURING THE AFTERNOON THOUGH NOT TO AREAS NE OF I-74
UNTIL CLOSER TO 6 PM. SLEET MIXED IN WITH SNOW FROM I-72 SOUTH
WITH FREEZING RAIN POSSIBLE TOO IN SE IL ESPECIALLY LATER THIS
AFTERNOON. SPC HAS CHANCE OF THUNDERSTORMS FROM I-72 SOUTH THIS
AFTERNOON AND ADDED ISOLATED THUNDERSTORMS LATER THIS AFTERNOON TO
SW AREAS. THIS COULD ENHANCE SNOWFALL RATES OF 1-2 INCHES PER
HOURS IN A FEW CONVECTIVE BANDS THIS LATER THIS AFTERNOON AND
EARLY EVENING. USED A 10-12:1 SNOW RATIO FOR THIS EVENT PER BUFKIT.
MIXED PRECIPITATION TO GRADUALLY SPREAD NORTHWARD DURING TONIGHT
WITH AND DIMINISH TO FREEZING DRIZZLE DURING OVERNIGHT AS WE LOSE
MID LEVEL MOISTURE. AS STATED ABOVE...ICE ACCUMULATIONS UP TO A
TENTH INCH AS FAR NORTH AS I-72 WITH LESS THAN A TENTH INCH NORTH
OF I-72. BETWEEN A TENTH AND A QUARTER INCH OF ICE IN SOUTHEAST IL
FROM I-70 SOUTH WITH HIGHEST AMOUNTS FROM EFFINGHAM AND CLAY
COUNTY SW. SNOWFALL AMOUNTS LESS THAN 1 INCH FROM I-70 SE WHILE 3-5
INCHES FROM I-55 NW WITH HIGHEST AMOUNTS OF 4-6 INCHES NW BY KNOX...
FULTON AND SCHUYLER COUNTIES. SOME BLOWING SNOW POSSIBLE ESPECIALLY
NW AREAS WITH EAST WINDS INCREASING TO 15-20 MPH WITH GUSTS TO
AROUND 30 MPH THIS AFTERNOON AND EVENING.
LINGERING FREEZING DRIZZLE AND LIGHT SNOW FRIDAY NORTHERN AREAS
AND CONTINUE THE WINTER WX ADVISORY THROUGH NOON FRIDAY NORTH OF I-72.
SHOULD RISE ABOVE FREEZING FOR CENTRAL AND SE COUNTIES TO CHANGE
ANY LINGERING PRECIPITATION TO PATCHY DRIZZLE. WEAKENING UPPER
LEVEL LOW MOVES INTO MI SAT/SAT NIGHT WITH PRECIPITATION ENDING OVER
CENTRAL IL AND LOW CLOUDS DECREASING. TEMPS COOLING WITH HIGHS
AROUND 30F NORTH AND UPPER 30S IN SE IL SAT. DRY WEATHER CONTINUES
SUNDAY WITH TEMPS MODIFYING AS UPPER LEVEL RIDGE PUSHES EAST INTO
THE MS VALLEY AS WEAK SURFACE HIGH SETTLES OVER IL BY MIDDAY SUNDAY.
LONG TERM...SUNDAY NIGHT THROUGH WEDNESDAY
EXTENDED MODELS HAVE TRENDED A BIT COLDER WITH NEXT CUTOFF UPPER
LEVEL LOW EJECTING NE FROM THE SOUTHERN ROCKIES INTO IL BY TUE
MORNING. GFS APPEARS TOO FAST WITH THIS CUTOFF UPPER LEVEL LOW AND
TRENDED FORECASTER TOWARD SLOWER ECMWF. BEST CHANCES OF
PRECIPITATION LATER MONDAY INTO TUESDAY. MAINLY RAIN OVER SE IL
WHILE MIX OF RAIN/SNOW OVER CENTRAL IL. UPPER LEVEL LOW TO LINGER
OVER THE GREAT LAKES REGION MIDDLE OF NEXT WEEK AND COULD KEEP
CLOUDS AROUND LONGER ALONG WITH LOW CHANCES OF LIGHT PRECIPITATION
ESPECIALLY NE AREAS. STUCK CLOSE TO ALLBLEND TEMPS DURING THIS
TIME WHICH IS CLOSE TO NORMAL FOR LATE FEBRUARY.
07
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 6 AM CST
FRIDAY FOR ILZ043>046-053>057-061>063-066>068-071>073.
WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO NOON CST
FRIDAY FOR ILZ027>031-036>038-041-042.
WINTER WEATHER ADVISORY UNTIL 6 AM CST FRIDAY FOR ILZ040-047>052.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
532 AM CST THU FEB 21 2013
.DISCUSSION...
ISSUED 340 AM CST THU FEB 21 2013
WILL CONTINUE THE WINTER WEATHER ADVISORY ACROSS CENTRAL AND
SOUTHEAST IL BUT START IT AT NOON IN AREAS FROM SPRINGFIELD SW
AND START AT 3 PM REST OF CWA. WINTER WX ADVISORY GOES THROUGH 6
AM FRIDAY EXCEPT THROUGH NOON FRIDAY FROM LINCOLN NORTH. INCREASED
ICE ACCUMULATIONS OVER SE IL TO BETWEEN A TENTH AND A QUARTER INCH
AND ALSO ADDED ISOLATED THUNDERSTORMS TO SW AREAS LATE TODAY.
BRUNT OF SNOW STILL EXPECTED TO DEVELOP FROM SW TO NE DURING THE
AFTERNOON AND CONTINUE THIS EVENING BEFORE DIMINISHING OVERNIGHT.
SNOWFALL AMOUNTS TO RANGE FROM LESS THAN 1 INCH FROM I-70 SE TO
3-5 INCHES FROM I-55 NW WITH HIGHEST AMOUNTS NW OF THE IL RIVER.
BETWEEN 1 AND 3 INCHES OF SNOW OVER EAST CENTRAL IL WITH ICE
ACCUMULATIONS UP TO A TENTH INCH AS FAR NORTH AS I-72.
SHORT TERM...TODAY THROUGH SUNDAY
STRONG 541 DM 500 MB LOW NEAR THE SOUTHERN AZ/NM BORDER THAT
BROUGHT SNOW AS FAR SOUTH AS TUCSON IN SOUTHERN AZ THIS PAST NIGHT
HAS 996 MB LOW PRESSURE OVER NE NM. 1042 DM 500 MB ARCTIC HIGH
PRESSURE OVER NW ONTARIO AND RIDGING SOUTHWARD INTO IL AND TN VALLEY
BRINGING ANOTHER COLD NIGHT WITH TEMPS IN THE MID TO UPPER TEENS
CENTRAL IL AND LOWER 20S IN SE IL.
MODELS EJECT UPPER LEVEL LOW NE INTO THE CENTRAL PLAINS BY THIS
EVENING AND INTO WI FRI EVENING. STRONG SURFACE LOW IN NE NM TO
WEAKEN AS IT EJECTS NE INTO SE KS BY THIS EVENING AND INTO NW IL
BY MIDDAY FRI. MODELS HAVE TRENDED FURTHER SE WITH LOW PRESSURE
TRACK AND ALSO WITH COLDER AIR. MODELS IN GOOD AGREEMENT THAT MOST
OF CENTRAL/SE IL WILL STAY DRY THIS MORNING WITH SNOW SPREADING NE
ACROSS AREA DURING THE AFTERNOON THOUGH NOT TO AREAS NE OF I-74
UNTIL CLOSER TO 6 PM. SLEET MIXED IN WITH SNOW FROM I-72 SOUTH
WITH FREEZING RAIN POSSIBLE TOO IN SE IL ESPECIALLY LATER THIS
AFTERNOON. SPC HAS CHANCE OF THUNDERSTORMS FROM I-72 SOUTH THIS
AFTERNOON AND ADDED ISOLATED THUNDERSTORMS LATER THIS AFTERNOON TO
SW AREAS. THIS COULD ENHANCE SNOWFALL RATES OF 1-2 INCHES PER
HOURS IN A FEW CONVECTIVE BANDS THIS LATER THIS AFTERNOON AND
EARLY EVENING. USED A 10-12:1 SNOW RATIO FOR THIS EVENT PER BUFKIT.
MIXED PRECIPITATION TO GRADUALLY SPREAD NORTHWARD DURING TONIGHT
WITH AND DIMINISH TO FREEZING DRIZZLE DURING OVERNIGHT AS WE LOSE
MID LEVEL MOISTURE. AS STATED ABOVE...ICE ACCUMULATIONS UP TO A
TENTH INCH AS FAR NORTH AS I-72 WITH LESS THAN A TENTH INCH NORTH
OF I-72. BETWEEN A TENTH AND A QUARTER INCH OF ICE IN SOUTHEAST IL
FROM I-70 SOUTH WITH HIGHEST AMOUNTS FROM EFFINGHAM AND CLAY
COUNTY SW. SNOWFALL AMOUNTS LESS THAN 1 INCH FROM I-70 SE WHILE 3-5
INCHES FROM I-55 NW WITH HIGHEST AMOUNTS OF 4-6 INCHES NW BY KNOX...
FULTON AND SCHUYLER COUNTIES. SOME BLOWING SNOW POSSIBLE ESPECIALLY
NW AREAS WITH EAST WINDS INCREASING TO 15-20 MPH WITH GUSTS TO
AROUND 30 MPH THIS AFTERNOON AND EVENING.
LINGERING FREEZING DRIZZLE AND LIGHT SNOW FRIDAY NORTHERN AREAS
AND CONTINUE THE WINTER WX ADVISORY THROUGH NOON FRIDAY NORTH OF I-72.
SHOULD RISE ABOVE FREEZING FOR CENTRAL AND SE COUNTIES TO CHANGE
ANY LINGERING PRECIPITATION TO PATCHY DRIZZLE. WEAKENING UPPER
LEVEL LOW MOVES INTO MI SAT/SAT NIGHT WITH PRECIPITATION ENDING OVER
CENTRAL IL AND LOW CLOUDS DECREASING. TEMPS COOLING WITH HIGHS
AROUND 30F NORTH AND UPPER 30S IN SE IL SAT. DRY WEATHER CONTINUES
SUNDAY WITH TEMPS MODIFYING AS UPPER LEVEL RIDGE PUSHES EAST INTO
THE MS VALLEY AS WEAK SURFACE HIGH SETTLES OVER IL BY MIDDAY SUNDAY.
LONG TERM...SUNDAY NIGHT THROUGH WEDNESDAY
EXTENDED MODELS HAVE TRENDED A BIT COLDER WITH NEXT CUTOFF UPPER
LEVEL LOW EJECTING NE FROM THE SOUTHERN ROCKIES INTO IL BY TUE
MORNING. GFS APPEARS TOO FAST WITH THIS CUTOFF UPPER LEVEL LOW AND
TRENDED FORECASTER TOWARD SLOWER ECMWF. BEST CHANCES OF
PRECIPITATION LATER MONDAY INTO TUESDAY. MAINLY RAIN OVER SE IL
WHILE MIX OF RAIN/SNOW OVER CENTRAL IL. UPPER LEVEL LOW TO LINGER
OVER THE GREAT LAKES REGION MIDDLE OF NEXT WEEK AND COULD KEEP
CLOUDS AROUND LONGER ALONG WITH LOW CHANCES OF LIGHT PRECIPITATION
ESPECIALLY NE AREAS. STUCK CLOSE TO ALLBLEND TEMPS DURING THIS
TIME WHICH IS CLOSE TO NORMAL FOR LATE FEBRUARY.
07
&&
.AVIATION...
ISSUED 532 AM CST THU FEB 21 2013
LARGE STRATOCUMULUS DECK AROUND 2000 FEET IS ADVECTING IN FROM THE
NORTHEAST...WITH AWIPS TIMING TOOLS INDICATING ARRIVAL FROM KBMI-
KCMI BY AROUND 13Z. RAP MODEL HUMIDITY PLOT AT 2500 FEET LINES UP
WELL...AND SUGGESTS IT SHOULD CONTINUE TOWARD KPIA AND KDEC TOWARD
16-17Z. WILL KEEP THESE MVFR CEILINGS OUT OF KSPI FOR NOW...BUT
CONDITIONS THERE WILL RAPIDLY DETERIORATE EARLY THIS AFTERNOON
WITH SNOW MOVING IN FROM THE SOUTHWEST TOWARD 21Z. THIS
PRECIPITATION WILL OVERSPREAD THE REMAINING TAF SITES BY ABOUT
23Z...WITH IFR OR LIFR CONDITIONS BECOMING WIDESPREAD. FORECAST
SOUNDINGS SHOWING SOME FREEZING RAIN POTENTIAL AT KSPI/KDEC EARLY
THIS EVENING AS WELL. HEAVIEST PRECIPITATION EXPECTED THROUGH
ABOUT 04-05Z...WITH A GRADUAL TREND TOWARD FREEZING DRIZZLE AT ALL
TAF SITES AFTER 06Z.
GEELHART
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 6 AM CST
FRIDAY FOR ILZ043>046-053>057-061>063-066>068-071>073.
WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO NOON CST
FRIDAY FOR ILZ027>031-036>038-041-042.
WINTER WEATHER ADVISORY FROM NOON TODAY TO 6 AM CST FRIDAY FOR
ILZ040-047>052.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
304 AM CST SAT FEB 23 2013
.SYNOPSIS...
06Z SFC ANALYSIS HAS AN OCCLUDED LOW NEARING THE MACKINAC STRAITS
WHILE HIGH PRESSURE WAS ACROSS THE PLAINS. DEW POINTS WERE IN THE
SINGLE DIGITS AND TEENS ACROSS THE PLAINS WITH 20S AND 30S ACROSS
THE GREAT LAKES AND OHIO VALLEY.
&&
.SHORT TERM...TODAY AND TONIGHT...
A COMBINATION OF CYCLONIC FLOW ALOFT AND VORT MAXES...MAINLY AT 700
MB IS PRODUCING FLURRIES/LIGHT SNOW ACROSS THE NORTHERN PART OF THE
CWFA AND UP INTO MINNESOTA. THE RAP TRENDS HAVE THE 700MB SHORTWAVE
ROTATING THROUGH DURING THE DAY WITH NEAR CONTINUOUS 700MB VORT
MAXES ROTATING THROUGH. THUS FLURRIES/VERY LIGHT SNOW WILL BE SEEN
ACROSS ROUGHLY THE NORTHERN HALF DURING THE MORNING.
FCST SOUNDINGS SHOW A DRYING ALOFT OCCURRING DURING THE AFTERNOON SO
ANY FLURRIES/LIGHT SNOW WILL GRADUALLY END.
BASED ON 0.5KM CONDENSATION PRESSURES/WIND...CLOUDS SHOULD STAY PUT
FOR MUCH OF THE MORNING BEFORE CLEARING STARTS FROM WEST TO EAST
DURING THE AFTERNOON. THE COLD POOL ALOFT MAY HELP GENERATE SOME
DIURNAL CLOUDS WHICH MAY SLOW THE RATE OF CLEARING DURING THE
AFTERNOON HOURS. ..08..
.LONG TERM...SUNDAY THROUGH NEXT FRIDAY...
THE EXTENDED STORM IS IN MUCH BETTER AGREEMENT IN MODEL FORECASTS
TONIGHT...AND IS FOCUSED ON A SURFACE LOW TRACK FROM OK/AR THROUGH
INDIANA MONDAY INTO TUESDAY. THE STORM SHOULD ONCE AGAIN HAVE A
BROAD UPPER LOW ASSOCIATED WITH IT...AND BY IN LARGE...THE UPPER LOW
SHOULD DOMINATE THE AREAL PLACEMENT OF RAIN AND SNOW. THE BIGGEST
DIFFERENCE IN MODELS TONIGHT...IS THAT NO MODEL FORECASTS AN
INTENSIFYING SURFACE LOW...OR EVEN A STRONG OCCLUDED LOW AS IT MOVES
PAST THE REGION. THIS WOULD INDICATE A MUCH LOWER RISK FOR A STRONG
WIND DRIVEN SNOW/BLIZZARD THAN THE EARLIER 12Z ECMWF WOULD HAVE
INDICATED. DESPITE THIS...THE STORM SHOULD BE ABLE TO PRODUCE A
HEALTHY DEFORMATION ZONE...AND ALL MODELS BRUSH THIS FORCING THROUGH
THE CENTRAL AND SOUTHERN CWA...AND THIS MAY REQUIRE HEADLINES TO BE
ISSUED TODAY IN OUR SOUTH. MODERATE SNOW ACCUMULATIONS OVER 3 INCHES
SEEM LIKELY WITH THIS SYSTEM...AND SHOULD A DIRECT HIT FROM THE DEF
ZONE OCCUR...HEAVY AMOUNTS ARE POSSIBLE. AS THE SYSTEM MOVES PAST
INTO THE LOWER GREAT LAKES...MORE ENERGY IS FORECAST BY THE GFS AND
ECMWF TO MOVE INTO THE WESTERN SIDE OF THE UPPER LOW...AND THIS
SHOULD PRODUCE AN EXTENDED PERIOD OF LIGHT SNOW BEGINNING TUESDAY
NIGHT INTO WEDNESDAY NIGHT. THE GFS IS MOST BULLISH...WITH 1 TO 2
INCHES OF SNOW FOR SEVERAL PERIODS IN A ROW FOR A LARGE AREA...WHILE
THE ECMWF IS MORE CONSERVATIVE. ANY WAY YOU SHAKE IT...IT APPEARS
UNSETTLED...CLOUDY...WITH LIGHT SNOW OR FLURRIES IN THE WAKE OF THE
EARLY WEEK STORM...AT LEAST THROUGH WEDNESDAY NIGHT.
LATE WEEK...MODELS SHOW A MUDDLED MESS OF NORTHERLY FLOW ALOFT.
THERE CERTAINLY COULD BE SOME SNOW POTENTIAL THERE...BUT IF IT WOULD
OCCUR...MOISTURE WOULD BE VERY LIMITED...AND AMOUNTS VERY LIGHT.
TEMPERATURES WILL AGAIN BE FORECAST TO AVERAGE BELOW NORMAL ON
HIGHS...MAINLY IN THE LOWER TO MID 30S THIS WEEK. LOWS IN THE TEENS
TO MID 20S ARE FORECAST FROM NORTHWEST TO SOUTHEAST...WITH THE
MILDEST LOWS ASSOCIATED WITH MONDAY NIGHT AND TUESDAY NIGHT AS WE
SHOULD EXPERIENCE HIGHER DEWPOINTS WITH THE POTENTIAL SNOW EVENT.
ERVIN
&&
.AVIATION...
MVFR/VFR CONDITIONS THROUGH AT LEAST 18Z/23 BEFORE SKIES CLEAR FROM
WEST TO EAST ACROSS IOWA/ILLINOIS. A DISTURBANCE ALOFT IS EXPECTED
TO KEEP A THREAT OF FLURRIES OR SHSN AT KDBQ AND POSSIBLY KCID/KMLI
THROUGH AT LEAST 18Z/23. HIGH PRESSURE BUILDING INTO THE MIDWEST AFT
00Z/24 IS EXPECTED TO RESULT IN VFR CONDITIONS. ..08..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1132 PM CST FRI FEB 22 2013
.SYNOPSIS...
ISSUED AT 257 PM CST FRI FEB 22 2013
SLOWLY FILLING SURFACE LOW THAT HAS MOVED NORTH ACROSS THE FORECAST
AREA TODAY IS CONTINUING TO MOVE UP INTO SOUTHERN WISCONSIN...AND AS
OF 2 PM WAS LOCATED WEST OF MADISON WISCONSIN...WITH A BROAD AREA OF
PRESSURE FALLS OVER WISCONSIN. A VERY WEAK TROUGH AXIS EXTENDS BACK
INTO NORTHERN IOWA...WHERE SNOW CONTINUES TO FALL VERY LIGHTLY. LOW
CLOUDS EXTEND BACK INTO NORTHERN MISSOURI. THERE IS AN AREA IN
NORTHWEST MISSOURI WHERE THE CLOUDS HAVE EITHER THINNED OR CLEARED
OUT ENTIRELY AS WE CAN SEE THE TEXTURE OF THE GROUND BENEATH ON
VISIBLE SATELLITE IMAGERY. THIS IS IN A OBSERVATIONAL DATA VOID
AREA...SO IT IS HARD TO DETERMINE WHAT EXACTLY IS GOING ON. AT
UPPER LEVELS...BROAD UPPER LEVEL TROUGH OVER THE WESTERN CONUS WITH
THE STRONG SHORTWAVE OVER THE MIDWEST ASSOCIATED WITH THIS STORM
SYSTEM. STRONG PRESSURE FALLS AHEAD OF THE SHORTWAVE IMPLY THAT IT
WILL CONTINUE NORTHEAST...BUT SMALL RISES BEHIND IT SHOW THAT IT IS
FILLING AND THE BROADER SCALE TROUGH IS STILL DEEPENING. ..LE..
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 257 PM CST FRI FEB 22 2013
THIS AFTERNOON THE SNOW BAND IS EXPECTED TO CONTINUE TO MOVE
NORTHEAST OUT OF THE AREA...AND PLAN ON ALLOWING THE WINTER STORM
WARNING AND ADVISORY EXPIRE HERE AT 3 PM. SOME FLURRIES WILL LIKELY
STILL AFFECT THE NORTHERN THIRD OF THE FORECAST AREA WITH SOME LOW
LEVEL CONVERGENCE AND LIFT GOING ON ACCORDING TO THE RUC THIS
EVENING. THUS...HAVE CONTINUED THE SLIGHT CHANCE POPS THIS EVENING
BUT WITH NO ACCUMULATIONS EXPECTED.
TONIGHT THE SURFACE LOW EJECTS OFF TO THE NORTHEAST...AND WILL BE
OVER THE UP OF MICHIGAN BY 06Z TONIGHT. THAT WILL DRAW THE LIFT AND
MOST OF THE MOISTURE OFF TO THE NORTHEAST...LEAVING US WITH SOME
LINGERING LOW LEVEL MOISTURE. IN FACT...ACCORDING TO SOUNDINGS WE
REMAIN FAIRLY WELL SATURATED BELOW 850MB THROUGH SATURDAY MORNING.
FLURRIES SHOULD BE POSSIBLE AS THE LEAST LITTLE WIGGLE IS GOING TO
PRODUCE THEM. IT APPEARS THAT WE WILL BE COLD ENOUGH AT THE TOP OF
THAT LAYER FOR THESE TO BE FLURRIES INSTEAD OF FREEZING DRIZZLE..BUT
LATER SHIFTS WILL HAVE TO WATCH FOR THIS. UPSTREAM MIN TEMPERATURES
FELL INTO THE TEENS OVER NEBRASKA AND KANSAS LAST NIGHT...SO HAVE
KEPT THE MIN TEMPS IN THE TEENS OVERNIGHT. MAY BE SLIGHTLY WARMER
WITH THE EXTRA CLOUD COVER...SO DID NOT BRING IN ANY SINGLE DIGIT
VALUES. THE EXTRA CLOUD COVER IS ALSO GOING TO KEEP TEMPS FROM
FALLING OFF VERY FAST OVERNIGHT...SO A SLOW DROP OFF IN THE EVENING
IS EXPECTED.
SATURDAY TO BE COLD AND QUIET WITH THE STORM OFF TO THE NORTHEAST
AND A GRADUAL CLEARING TREND FROM THE SOUTH. WE ARE NOT BRINGING IN
A COLD AIRMASS BEHIND THIS SYSTEM...BUT WITH THE SNOW COVER WE ARE
GOING TO BE COLDER THAN WE WOULD WITHOUT. SO...EXPECT HIGHS IN THE
20S TO NEAR 30. LINGERING LOW LEVEL MOISTURE SHOULD LIFT TO
AFTERNOON STRATOCUMULUS...BUT STILL ALLOWING A FAIR AMOUNT OF
SUNSHINE THROUGH. ..LE..
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 257 PM CST FRI FEB 22 2013
ANOTHER MAJOR AND STRONGER WINTER STORM FOR MONDAY/TUESDAY THE MAIN
FORECAST CHALLENGE.
OVERVIEW...INITIALIZATION GOOD TO EXCELLENT UPSTREAM INTO THE NORTH
PACIFIC. THE 18Z VERIFICATION SUPPORT ALL 4 LONGER RANGE SOLUTIONS
VERIFYING WELL AND ARE ALL SIMILAR. THATS THE GOOD NEWS...UNLESS ONE
LIKES LOTS OF SNOW...THEY ALL PUT AREA IN THE WHEELHOUSE OF A MAJOR
WINTER STORM WITH STRONG WINDS. PREFER A BLEND OF ALL 4 AS A MIX
WHICH SUPPORTS MOST OR ALL THE AREA TO PICK UP ANOTHER 4-6+ INCHES OF
SNOW WITH LOCALLY UP TO OVER 12 INCHES POSSIBLE WITH WINDS OF 20 TO
35+ MPH AND POSSIBLY HIGHER. THE CONSISTENCY OF FORCING OF UPPER JET
STRUCTURE TOOLS ALL SUGGEST IF THIS TREND CONTINUES THE NEXT 24 HOURS
THAT OUR AREA WILL SEE A MAJOR...HIGHER END WINTER STORM EVENT WITH
POSSIBLE NEAR BLIZZARD CONDITIONS. WILL UPDATE THE LOCAL HWODVN
HAZARDOUS WEATHER OUTLOOK PRODUCT FOR STRONGER AND HIGHER IMPACT
WORDING.
SATURDAY NIGHT AND SUNDAY...VERY MINOR CHANGES WITH LESS CLOUDS ARE
LIKELY SUPPORTING LOWER MINS FROM OUR SNOW-PACK AND HIGHER MAX TEMP
VALUES FROM LATE FEBRUARY SUNSHINE. LATER SHIFTS MAY NEED TO BUMP
HIGHS A FEW MORE DEGREES DUE TO THE SUNSHINE. SUNDAY NIGHT...SEE
INCREASING CLOUDS AND KEPT VERY LOW POPS FAR WEST SECTIONS OVERNIGHT
AS LEADING EDGE OF ELEVATED FORCING FOR THE NEXT MAJOR WINTER STORM
ARRIVES WITH MAIN BRUNT OF FORCING ON TAP TO IMPACT THE AREA LATER ON
MONDAY PM HOURS INTO TUESDAY.
MONDAY THROUGH NEXT WEDNESDAY...HAVE UPPED POPS MONDAY NIGHT AND
TUESDAY TO LIKELY WITH MODERATE TO HEAVY SNOW AMOUNTS SUGGESTED.
NUMEROUS TOOLS SUGGEST MOST OF THE AREA TO SEE WELL OVER 4+ INCHES
WITH MOST RELIABLE TOOLS ALL SUGGESTING A SWATH OF 6-12+ INCHES OF
HEAVY SNOW THAT RIGHT NOW IS TRENDING TOWARD A IRK-MUS-FEP LINE.
THIS SHOULD BE BETTER CLARIFIED IN THE NEXT 24 HOURS. IF PHASING
ON THE BACK SIDE OCCURS AS SUGGESTED BY SOME SOLUTIONS WITH STRONGER
OCCLUSION THEN STRONGER COLD CONVEYOR BELT SUGGESTED AND NEAR
BLIZZARD CONDITIONS LIKELY. SOME TOOLS SUGGEST WIND GUSTS OF 40-45
MPH WHICH ARE VERY CLOSE TO BLIZZARD THRESHOLD FOR LATER SHIFTS TO
MONITOR. THERE IS NO DOUBT THIS WILL BE A MAJOR EVENT LAST 12-18+
HOURS AND LIKELY GREATER THAN THE EVENT THE PAST 24 HOURS. THIS IS
A DEVELOPING SYSTEM THAT WILL STRENGTHEN VERSUS A WEAKENING AND
FILLING SYSTEM THAT PASSED. ADD WERE IN THE NATURAL BAROCLINIC
ZONE OF A PRONOUNCED SNOW AND NO SNOW LINE...THIS MAKES RISK OF A
MAJOR EVENT GREATER. THE DATA AS OF NOW...SUPPORTS AT LEAST PART
OF THE AREA WILL SEE A MAJOR WINTER STORM. AREA SNOW TO LIQUID WATER
EQUIVALENT RATIOS ARE SUGGESTED TO BE IN THE 12-15 TO 1 RANGE. ARE
TEMPERATURES SHOULD STAY IN THE MID 20S TO LOWER 30S FOR THIS EVENT.
THURSDAY AND FRIDAY...DRY WITH BELOW NORMAL TEMPERATURES AND WITH
AN EVEN GREATER THICKER AND FRESH SNOW PACK LIKELY...AREA TEMPS ARE
AGAIN PROBABLY TOO MILD. MINS COULD BE AT LEAST 5 TO 10 DEGREES TOO
MILD FOR LATER SHIFTS TO RECONSIDER. NORTHWESTERLY FLOW AND BELOW
NORMAL TEMPERATURES REMAIN APPEAR LIKELY INTO THE FIRST FEW DAYS OF
MARCH...ALL INDICATIONS ARE THIS MARCH WILL NOTHING LIKE THE
RECORD WARM MARCH OF 2012.
NICHOLS
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1127 PM CST FRI FEB 22 2013
CYCLONIC FLOW AROUND LOW PRESSURE OVER NORTHERN LAKE MICHIGAN
AND HIGH LOW LEVEL MOISTURE WILL KEEP CLOUDS BASED 2KT AND 4KFT IN
PLACE EARLY SATURDAY MORNING. SKIES SHOULD CLEAR FROM WEST TO EAST
BEGINNING AROUND SUNRISE WITH THE CLEAR LINE REACHING THE
MISSISSIPPI RIVER BY NOON. VISIBILITIES WERE REMAIN AOA 6SM WITH
WEST TO SOUTHWEST WINDS AROUND 10 KNOTS.
DLF
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...LE
SHORT TERM...LE
LONG TERM...WDN
AVIATION...DLF
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
1050 PM MST FRI FEB 22 2013
.AVIATION...
06Z TAF CYCLE
UPPER DISTURBANCE PASSING OVER NORTH CENTRAL/NORTHEAST NEW MEXICO
BEFORE 12Z AND WILL BE ACCOMPANIED BY A COLD FRONT. SHSN ALREADY
WANING WEST OF THE CENTRAL MT CHAIN...WHILE SCT MAINLY MVFR
CIGS/VBSYS IN SHSN/BR WILL OCCASIONALLY OBSCURE MTS OVER THE
NORTHEAST THIRD OR SO OF THE STATE UNTIL AROUND 09Z THEN SHOULD
TAPER OFF AS THE DISTURBANCE TRACKS INTO THE TX PANHANDLE. WINDS ALOFT
BECOMING WLY AND SFC LEE TROUGH DEVELOPING AFT 23/18Z.
&&
.PREV DISCUSSION...324 PM MST FRI FEB 22 2013...
ANOTHER WEAK UPPER WAVE SLIDING ACROSS NORTHERN NM IN FAST NNW FLOW
WILL KEEP THE SNOW MACHINE GOING OVER THE HIGH TERRAIN THROUGH EARLY
SATURDAY. LOCAL HI RES WRF...NAM12...AND HRRR SOLUTIONS SHOW MESOSCALE
FEATURES WITHIN THE LARGER SCALE REGIME SLIDING SOUTHWARD OUT OF THE
NORTHERN MTS TONIGHT INTO THE RIO GRANDE VALLEY FROM SANTA FE TO THE
ABQ METRO AREA THIS EVENING. INCREASED POPS ACCORDINGLY AND PLACED A
DUSTING TO 1 INCH FOR THESE AREAS. FOR THE HIGH TERRAIN THERE HAS
BEEN AN EBB AND FLOW OF LIGHT TO MODERATE SNOW AND SNOW SHOWERS SINCE
THURSDAY MORNING WITH 1-4 INCHES OF SNOW EACH 12HR PERIOD ADDING UP
TO SOME MODEST ACCUMULATIONS. TONIGHT WILL FEATURE ANOTHER 1-4 INCHES
ABOVE 7500 FEET. A DISTINCT BREAK WILL TAKE SHAPE FOR THE ENTIRE
AREA SATURDAY BEHIND TONIGHTS UPPER WAVE.
A HIGHER IMPACT STORM WILL MOVE OVER NORTHERN NM SATURDAY NIGHT AND
SUNDAY. THIS SYSTEM WILL BRING WITH IT A STRONG PACIFIC COLD FRONT
AND ANOTHER ROUND OF WIND AND SNOW. THE NORTHERN MTS WILL SEE AN
ADDITIONAL SEVERAL INCHES OF SNOW BUT WITH MORE WIND AND COLDER
TEMPS THAN THE PAST 36 HRS SO SOME WINTER HIGHLIGHTS ARE EXPECTED.
THE NE PLAINS WILL BE IN THE ACTION AS WELL WITH A TROWAL FEATURE
SLIDING OVER THE AREA AS THE STORM SYSTEM DEEPENS OVER THE PLAINS
STATES. TEMPS WILL DIVE BACK 10 TO 20F BLW NORMAL ONCE AGAIN.
CONFIDENCE IS NOT HIGH ENOUGH FOR A WINTER STORM WATCH AT THIS
TIME BUT IF MODEL TRENDS CONTINUE TO STRENGTHEN THAT COULD CHANGE.
COLD TEMPS WILL CONTINUE INTO MONDAY AND TUESDAY WITH BREEZY TO
LOCALLY WINDY CONDITIONS EXPECTED. BY LATE TUESDAY GUIDANCE SHOWS
ANOTHER WAVE SLIDING SE OVER THE AREA WITH MORE SNOWFALL ACCUMS
FOR THE NORTHERN HIGH TERRAIN. ANOTHER BREAK IS ON TAP WEDNESDAY
BEFORE ANOTHER FAST MOVING SHEARED WAVE SLIDES OVER THURSDAY. BY
THE END OF THE WEEK GUIDANCE FINALLY STOPS THE WAVE TRAIN AND
SLOWLY PUSHES A RIDGE TOWARD THE AREA WITH SLIGHTLY WARMER TEMPS.
GUYER
&&
.FIRE WEATHER...
AN UPPER LEVEL TROUGH WILL MOVE RAPIDLY TO THE EAST ACROSS NORTHERN
NM TONIGHT PRODUCING LIGHT TO MODERATE SNOWFALL IN THE HIGHER
TERRAIN AND ISOLATED AREAS OF LIGHT SNOW IN THE LOWER ELEVATIONS.
MOIST NORTHWEST TO WEST FLOW ACROSS NORTHERN AND CENTRAL NM TONIGHT
WILL KEEP RELATIVE HUMIDITIES ABOVE NORMAL THROUGH SATURDAY MORNING.
INCREASING 700 MB WINDS AND THE FORMATION OF WEAK SURFACE LOW
PRESSURE IN EASTERN NM ON SATURDAY WILL RESULT IN WEST WIND GUSTS UP
TO 35 MPH EAST OF THE CENTRAL MOUNTAINS ALONG AND SOUTH OF I-40.
MINIMUM RELATIVE HUMIDITY IN THESE AREAS WILL GENERALLY BE IN THE
17-25 PERCENT RANGE...SO THE RISK OF CRITICAL FIRE WEATHER
CONDITIONS DEVELOPING SATURDAY AFTERNOON APPEARS LOW. VENTILATION
SATURDAY WILL BE FAIR TO GOOD WEST OF THE CONTINENTAL DIVIDE AND
GOOD TO VERY GOOD EAST OF THE DIVIDE.
A SIGNIFICANTLY STRONGER AND COLDER UPPER LEVEL LOW WILL MOVE FROM
THE EASTERN GREAT BASIN ACROSS NORTHERN AND CENTRAL NM SATURDAY
NIGHT THROUGH SUNDAY AND THEN EXIT ACROSS NORTHEASTERN NM SUNDAY
NIGHT. THE TRACK OF THIS SYSTEM HAS BEEN PROGRESSIVELY FURTHER TO
THE SOUTH ON MODEL RUNS OVER THE PAST 48 HOURS. THIS TRACK WILL
GENERATE THE STRONGEST WINDS ACROSS SOUTHERN NM ON SUNDAY. THE
DRIEST LOW LEVEL AIR AND STRONGEST WINDS WILL LIKELY STAY TO THE
SOUTH OF THE FIRE DISTRICT. WINDS WILL STILL BE MODERATE SUNDAY WITH
GUSTS BETWEEN 30 TO 35 MPH ACROSS CENTRAL NM...ESPECIALLY SOUTH OF
I-40. MOISTURE ACCOMPANYING THIS UPPER LEVEL TROUGH WILL KEEP
DAYTIME RELATIVE HUMIDITY VALUES NEAR OR ABOVE 20 PERCENT...SO
CRITICAL FIRE WEATHER CONDITIONS WILL BE UNLIKELY. SUSTAINED
NORTHWEST WINDS SUNDAY WILL RANGE FROM 10 TO 25 MPH....RESULTING IN
VERY GOOD TO EXCELLENT VENTILATION. AS THE UPPER LOW MOVES EASTWARD
ACROSS WESTERN OK SUNDAY NIGHT...WRAP-AROUND MOISTURE WILL KEEP
RELATIVE HUMIDITY HIGH ACROSS EASTERN NM....WHILE DECREASING WIND
SPEEDS AND RESIDUAL LOW LEVEL MOISTURE ACROSS CENTRAL AND WESTERN NM
WILL ALLOW FOR STRONG RELATIVE HUMIDITY RECOVERIES SUNDAY NIGHT
THROUGH MONDAY MORNING.
HIGH PRESSURE WILL BUILD ACROSS NM FROM THE WEST ON MONDAY WITH
LIGHTER WINDS AND DRIER LOW LEVEL AIR MOVING INTO THE REGION.
AFTERNOON WINDS IN THE EASTERN PLAINS WILL CREATE FAIR TO GOOD
VENTILATION...BUT LIGHTER WINDS ACROSS THE REMAINDER OF NM WILL
CREATE ONLY POOR TO FAIR VENTILATION.
ANOTHER UPPER LEVEL TROUGH MAY AFFECT NORTHERN AND CENTRAL NM ON
TUESDAY...MOST LIKELY IN THE AFTERNOON TO EVENING HOURS...THOUGH
MODEL GUIDANCE STILL VARIES ON TIMING. THIS SYSTEM WOULD MOST LIKELY
BRING SNOW TO NORTHERN NM...BUT CENTRAL NM COULD RECEIVE SNOW GIVEN
A SLIGHT ADJUSTMENT IN THE TRACK OF THE STORM. THIS TROUGH WILL MOST
LIKELY KEEP TEMPERATURES BELOW NORMAL AND RELATIVE HUMIDITY ABOVE
NORMAL THROUGH MIDWEEK. WEAK HIGH PRESSURE WILL DRIFT ACROSS NM
WEDNESDAY WITH A GREATER POSSIBILITY FOR STRONGER MORNING INVERSIONS
AND POORER DAYTIME VENTILATION. 28
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
421 AM EST SAT FEB 23 2013
.SYNOPSIS...
OUR REGION IS WEDGED BETWEEN ONE LOW PRESSURE CENTER MOVING FROM
THE NORTHERN GREAT LAKES INTO CANADA...AND ANOTHER ONE DEVELOPING
WHILE HEADING OFFSHORE THE MIDATLANTIC COAST. WE CAN EXPECT CLOUDS
WITH INCREASING CHANCES OF LIGHT RAIN AND SNOW TODAY INTO TONIGHT.
SOME LOCATIONS MAY EVEN SEE PATCHY FREEZING DRIZZLE OR LIGHT
FREEZING RAIN INTO TONIGHT. TEMPERATURES WILL NOT BE MOVING MUCH
THE NEXT SEVERAL DAYS.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
1000 PM UPDATE...CUT BACK ON POPS FOR MOST OF THE AREA THROUGH
DAYBREAK BASED ON OBS AND CURRENT TRENDS. THE RUC 500 VORTICITY
FIELD SEEMS TO HAVE A GOOD HANDLE ON WHERE THE BEST SHOT FOR
PRECIP WILL BE OVERNIGHT. RIGHT NOW WE HAVE A WEAK LOBE OF
VORTICITY STRETCHING FROM THE FINGER LAKES SOUTH AND EAST INTO
NEPA. THIS LOBE WILL MOVE NORTHEAST THROUGH 09Z THROUGH CNY AND
OTSEGO/DELAWARE COUNTY. AS THIS HAPPENS THE WEAK RETURNS WE ARE
SEEING NOW ON RADAR IN THE FORM OF VERY LIGHT SNOW OR FLURRIES
WILL MOVE NORTHEAST AND EVENTUALLY OUT OF THE AREA BY 12Z.
MEANWHILE A MORE IMPRESSIVE AREA OF DRIZZLE AND LIGHT PRECIP IN
THE PHILLY AREA WILL BE CAREFULLY WATCHED. AT THIS POINT BASED ON
RADAR AND MATCHING IT UP WITH THE UPPER LEVEL LIFT...THIS BATCH
SHOULD MOVE NORTH AND EAST WHICH WOULD KEEP IS AWAY FROM OUR SE
CWA. THIS IS CONFIRMED BY DESCENT IN THE COLUMN AT KAVP. IT
APPEARS MORE ENERGY NOW OVER THE OHIO VALLEY WILL SWING THROUGH
BETWEEN 12Z AND 15Z ESPECIALLY OVER THE WESTERN CWA AND THIS IS
WHEN I WILL RAMP POPS BACK UP AGAIN. A QUICK GLANCE AT THE 0Z
MODELS AND IT LOOKS LIKE FAIRLY LIGHT QPF THROUGH EARLY
AFTERNOON...AND MAIN FOCUS OF INTEREST MAY BE THIS EVENING/TONIGHT
FOR WINTER POTENTIAL. MORE WITH THE NEXT UPDATE...
945 PM UPDATE...ISOLATED TO SCATTERED SNOW SHOWERS
CONTINUE OVER THE AREA AS SECONDARY ALTHOUGH WEAKER SHORT WAVE
CROSSES THE CWA. AFTER THIS SHORT WAVE PASSES ACTIVITY MAY EVEN
DIMINISH FURTHER FOR THE REMAINDER OF THE OVERNIGHT PERIOD. ONLY
MINOR TEMP ADJUSTMENTS NEEDED.
640 PM UPDATE...LOCAL RADAR SHOWS SCATTERED LIGHT RETURNS ACROSS
THE EASTERN CWA PRIMARILY EAST OF I81. AT THE AFC NOT MUCH IS
BEING REPORTED WITH TEMP/DEW POINT SPREADS OF 10-15 DEGREES. AT
SOME SITES FLURRIES OR VERY BRIEF SNOW SHOWERS HAVE OCCURRED. THIS
ACTIVITY WAS INITIATED BY A MID LEVEL SHORT WAVE WITH ANOTHER ONE
EXPECTED LATER THIS EVENING BUT ONLY SCATTERED ACTIVITY IS
FORECAST WITH THIS SECOND FEATURE. WILL CONTINUE WITH JUST LOW
CHIC POPS THROUGH THE OVERNIGHT PERIOD WITH PRECIP FALLING AS JUST
SNOW THROUGH 06Z. AFTER 06Z MID LEVEL WARMING COMBINED WITH
SHALLOW MOISTURE COULD PRODUCE SOME PATCHY FREEZING DRIZZLE
ACROSS THE SOUTHERN TIER AND NE PA. CURRENT FORECAST IN GOOD
SHAPE.
3 PM UPDATE...
A NW TO SE BAND OF LIGHT PRECIP IS MOVG NE INTO THE AREA. IT IS
DRYING AS IT MOVES IN. THE BEST CHC OF ANYTHING THIS AFTN WILL BE
LIGHT SNOW IN THE FINGER LAKES. ACCUMS LESS THAN AN INCH. REST OF
THE CWA LITTLE TO NOTHING. BETTER LIFT AND MOISTURE RETURNS LATE
TONIGHT WITH LOW CLOUDS SO MAYBE SOME LIGHT PRECIP IN THE FORM OF
FLURRIES OR MAYBE FREEZING DRIZZLE. TOTAL QPF ONLY A HUNDREDTH OR
TWO AT BEST.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH SUNDAY NIGHT/...
3 PM UPDATE...
SATURDAY AND SATURDAY NIGHT BETTER DYNAMICS AND MOISTURE MOVES IN
AHEAD AN INTENSIFYING COASTAL LOW MOVG NE TO LONG ISLAND SAT NGT
AND A DEEP STACKED LOW OVER THE MI UP MOVG EAST. UNFORTUNATELY THE
SW FLOW IS BRINGING IN WARM AIR. PRECIP MAY START AS SNOW THEN MIX
OR CHANGE TO RAIN SAT. COLDER AIR COMES IN SAT NGT TO CHANGE MIXED
PRECIP BACK TO SNOW. LOW LEVEL CAA WILL BRING SFC TEMPS BELOW
FREEZING FIRST SO FREEZING RAIN IS POSSIBLE IN NE PA AND THE
CATSKILLS SAT EVE. THE BEST CHC OF ACCUMULATING SNOW WILL BE THE
HIGH TERRAIN OF THE CATSKILLS. MAYBE ADVISORY SNOW THERE. THE
POCONOS MAY BE TOO WARM.
SUNDAY AND SUNDAY NIGHT WE WILL BE UNDER THE UPPER LEVEL LOW AS IT
MOVES SE BEHIND THE COASTAL SFC NOREASTER. COLD AIR ADVECTION AND
A WEAK FLOW OFF THE GREAT LAKES WILL MEAN WIDESPREAD LIGHT SNOW
SHWOERS SUNDAY TO SUNDAY NIGHT. THE QUESTION IS WHEN IT WILL END.
FOR NOW HAVE IT ENDING SUN NGT BUT IT COULD CONTINUE INTO MONDAY.
BY MONDAY NIGHT SFC HIGH PRESSURE IS OVER THE CWA WITH AN UPPER
LEVEL RIDGE JUST UPSTREAM SO LOW CLOUDS AND SNOW SHOWERS WILL
TAPER OFF SUN NGT TO MON. WITH THE NW FLOW AND LAKE ENHANCEMENT
AND NEARNESS TO THE UPPER LEVEL LOW THE NRN COUNTIES COULD GET A
FEW INCHES AGAIN.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
345 AM UPDATE...
WELCOME TO CUTOFF COUNTRY. A PATTERN MORE REMINISCENT OF EARLY
SPRING...THAT IS...AMPLIFIED WITH CUTOFF LOWS...WILL DOMINATE THE
LONG TERM PERIOD OF THE FORECAST. DAYTIME TEMPERATURES THOUGH
WILL NOT STRAY MUCH FROM CLIMATOLOGY.
ECMWF AND GFS AGREE THAT AN UPPER LOW WILL BE SHIFTING ITS WAY UP
THE OHIO VALLEY TUESDAY INTO TUESDAY NIGHT. THE DETAILS ARE A BIT
DIFFERENT AS TO WHAT HAPPENS FROM THERE...BUT BOTH SHOW A VERSION
OF A NORTHERN HIGH PLAINS UPPER TROUGH DIGGING INTO THE MIDWEST
AND CAPTURING/CONSOLIDATING WITH THE ORIGINAL UPPER LOW. WHEN
THAT OCCURS...IT WILL BE STUCK IN OUR VICINITY AND IN ABSOLUTELY
NO RUSH TO GO ANYWHERE THROUGH FRIDAY. FOR US...THAT MEANS PLENTY
OF CLOUD COVER...OCCASIONAL SNOW AND/OR RAIN SHOWERS...AND LITTLE
MOVEMENT IN TEMPERATURES DIURNALLY.
ON THE LEADING EDGE OF THIS PATTERN...MODEL CONSENSUS HAS SHIELD
OF PRECIPITATION MOVING IN A BIT SLOWER THAN PREVIOUS
FORECAST...MAINLY LATE TUESDAY INTO TUESDAY NIGHT. THIS SLOWER
TREND IS NOT A SURPRISE GIVEN AMPLIFIED NATURE TO PATTERN. GRIDS
HAVE BEEN ADJUSTED ACCORDINGLY. PRESSURE GRADIENT BETWEEN LARGE
DEPARTING NEW ENGLAND HIGH AND INCOMING LOW WILL BE QUITE
STEEP...AND I THUS INCREASED WINDS FOR THE TUESDAY NIGHT/EARLY
WEDNESDAY PERIOD. NOT SURE YET HOW MUCH OF THE STRONG WINDS ALOFT
WILL BE ABLE TO MIX DOWN...THE BOUNDARY LAYER MAY BE FAIRLY
STABLE. ONE NOTEWORTHY DIFFERENCE IN THE MODELS IS THAT THE GFS IS
COLDER AT 925MB THAN AT 850MB /WHERE IT IS MAINLY ABOVE FREEZING/
AS THE PRECIPITATION MOVES IN TUESDAY. ECMWF MEANWHILE IS VICE-
VERSA. SO THE GFS WOULD SUGGEST POSSIBLE FREEZING RAIN WHILE THE
ECMWF IS MORE OF A SIMPLE RAIN/SNOW MIX. I HAVE NOT ADDED CHANCE
OF FREEZING RAIN TO GRIDS JUST YET...BUT THIS POTENTIAL WILL HAVE
TO BE ASSESSED AS THE EVENT GETS CLOSER.
&&
.AVIATION /09Z SATURDAY THROUGH WEDNESDAY/...
06Z UPDATE...
COMPLICATED AVIATION FORECAST DURING THIS TAF PERIOD...WITH REGION
IN MOIST FEED BETWEEN DEVELOPING LOW AROUND THE MID ATLANTIC
COAST...AND ANOTHER LOW IN THE NORTHERN GREAT LAKES. LOW END VFR
TO MVFR CIGS...COURTESY OF SHALLOW MOISTURE WHICH WILL
OCCASIONALLY YIELD PATCHY FREEZING DRIZZLE KAVP-KBGM-KELM LATER
THIS MORNING...BRIEF IFR CIG ALSO NOT OUT OF THE QUESTION LATER
THIS MORNING FOR KBGM /AFTER 12Z/. CIGS GENERALLY STAY IN MVFR
CATEGORY WITH LIGHT RAIN OR DRIZZLE DURING THE DAY CAUSING MVFR
VIS AS OCCLUDED FRONT PASSES OVERHEAD WITH CONTINUED SHALLOW
MOISTURE. BEHIND OCCLUDED FRONT TONIGHT...SATURATED LAYER GETS
SQUEEZED BELOW LOWERING INVERSION AND IFR CIGS MAY IMPACT MOST
TERMINALS. FREEZING DRIZZLE MAY ALSO RE-ENTER THE PICTURE.
.OUTLOOK...
LATE SAT NGT...MVFR/IFR IN MIXED PCPN.
SUN...VFR...MAYBE MVFR IN NY WITH LAKE ENHANCED SNOW SHOWERS.
MON...VFR.
TUE...MVFR/IFR IN RAIN AND/OR SNOW.
WED...MVFR IN LAKE ENHANCED SNOW SHOWERS.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...HEDEN/MDP
NEAR TERM...HEDEN/RRM/TAC
SHORT TERM...TAC
LONG TERM...MDP
AVIATION...MDP
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
105 AM EST SAT FEB 23 2013
.SYNOPSIS...
A WEAK STORM SYSTEM AND FRONTAL COMPLEX WILL BRING A LIGHT WINTRY
MIX OF SNOW, RAIN, OR FREEZING DRIZZLE OVERNIGHT. STEADIER
PRECIPITATION IS LIKELY FOR MUCH OF THE AREA SATURDAY AFTERNOON
AND EVENING...ASSOCIATED WITH A DEVELOPING STORM OFF THE MID
ATLANTIC COAST. ONCE AGAIN...WE WILL LIKELY SEE A MIXTURE OF RAIN
AND SNOW...AND MAYBE FREEZING RAIN.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
1000 AM UPDATE...CUT BACK ON POPS FOR MOST OF THE AREA THROUGH
DAYBREAK BASED ON OBS AND CURRENT TRENDS. THE RUC 500 VORTICITY
FIELD SEEMS TO HAVE A GOOD HANDLE ON WHERE THE BEST SHOT FOR
PRECIP WILL BE OVERNIGHT. RIGHT NOW WE HAVE A WEAK LOBE OF
VORTICITY STRETCHING FROM THE FINGER LAKES SOUTH AND EAST INTO
NEPA. THIS LOBE WILL MOVE NORTHEAST THROUGH 09Z THROUGH CNY AND
OTSEGO/DELAWARE COUNTY. AS THIS HAPPENS THE WEAK RETURNS WE ARE
SEEING NOW ON RADAR IN THE FORM OF VERY LIGHT SNOW OR FLURRIES
WILL MOVE NORTHEAST AND EVENTUALLY OUT OF THE AREA BY 12Z.
MEANWHILE A MORE IMPRESSIVE AREA OF DRIZZLE AND LIGHT PRECIP IN
THE PHILLY AREA WILL BE CAREFULLY WATCHED. AT THIS POINT BASED ON
RADAR AND MATCHING IT UP WITH THE UPPER LEVEL LIFT...THIS BATCH
SHOULD MOVE NORTH AND EAST WHICH WOULD KEEP IS AWAY FROM OUR SE
CWA. THIS IS CONFIRMED BY DESCENT IN THE COLUMN AT KAVP. IT
APPEARS MORE ENERGY NOW OVER THE OHIO VALLEY WILL SWING THROUGH
BETWEEN 12Z AND 15Z ESPECIALLY OVER THE WESTERN CWA AND THIS IS
WHEN I WILL RAMP POPS BACK UP AGAIN. A QUICK GLANCE AT THE 0Z
MODELS AND IT LOOKS LIKE FAIRLY LIGHT QPF THROUGH EARLY
AFTERNOON...AND MAIN FOCUS OF INTEREST MAY BE THIS EVENING/TONIGHT
FOR WINTER POTENTIAL. MORE WITH THE NEXT UPDATE...
945 PM UPDATE...ISOLATED TO SCATTERED SNOW SHOWERS
CONTINUE OVER THE AREA AS SECONDARY ALTHOUGH WEAKER SHORT WAVE
CROSSES THE CWA. AFTER THIS SHORT WAVE PASSES ACTIVITY MAY EVEN
DIMINISH FURTHER FOR THE REMAINDER OF THE OVERNIGHT PERIOD. ONLY
MINOR TEMP ADJUSTMENTS NEEDED.
640 PM UPDATE...LOCAL RADAR SHOWS SCATTERED LIGHT RETURNS ACROSS
THE EASTERN CWA PRIMARILY EAST OF I81. AT THE AFC NOT MUCH IS
BEING REPORTED WITH TEMP/DEW POINT SPREADS OF 10-15 DEGREES. AT
SOME SITES FLURRIES OR VERY BRIEF SNOW SHOWERS HAVE OCCURRED. THIS
ACTIVITY WAS INITIATED BY A MID LEVEL SHORT WAVE WITH ANOTHER ONE
EXPECTED LATER THIS EVENING BUT ONLY SCATTERED ACTIVITY IS
FORECAST WITH THIS SECOND FEATURE. WILL CONTINUE WITH JUST LOW
CHIC POPS THROUGH THE OVERNIGHT PERIOD WITH PRECIP FALLING AS JUST
SNOW THROUGH 06Z. AFTER 06Z MID LEVEL WARMING COMBINED WITH
SHALLOW MOISTURE COULD PRODUCE SOME PATCHY FREEZING DRIZZLE
ACROSS THE SOUTHERN TIER AND NE PA. CURRENT FORECAST IN GOOD
SHAPE.
3 PM UPDATE...
A NW TO SE BAND OF LIGHT PRECIP IS MOVG NE INTO THE AREA. IT IS
DRYING AS IT MOVES IN. THE BEST CHC OF ANYTHING THIS AFTN WILL BE
LIGHT SNOW IN THE FINGER LAKES. ACCUMS LESS THAN AN INCH. REST OF
THE CWA LITTLE TO NOTHING. BETTER LIFT AND MOISTURE RETURNS LATE
TONIGHT WITH LOW CLOUDS SO MAYBE SOME LIGHT PRECIP IN THE FORM OF
FLURRIES OR MAYBE FREEZING DRIZZLE. TOTAL QPF ONLY A HUNDREDTH OR
TWO AT BEST.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH MONDAY/...
3 PM UPDATE...
SATURDAY AND SATURDAY NIGHT BETTER DYNAMICS AND MOISTURE MOVES IN
AHEAD AN INTENSIFYING COASTAL LOW MOVG NE TO LONG ISLAND SAT NGT
AND A DEEP STACKED LOW OVER THE MI UP MOVG EAST. UNFORTUNATELY THE
SW FLOW IS BRINGING IN WARM AIR. PRECIP MAY START AS SNOW THEN MIX
OR CHANGE TO RAIN SAT. COLDER AIR COMES IN SAT NGT TO CHANGE MIXED
PRECIP BACK TO SNOW. LOW LEVEL CAA WILL BRING SFC TEMPS BELOW
FREEZING FIRST SO FREEZING RAIN IS POSSIBLE IN NE PA AND THE
CATSKILLS SAT EVE. THE BEST CHC OF ACCUMULATING SNOW WILL BE THE
HIGH TERRAIN OF THE CATSKILLS. MAYBE ADVISORY SNOW THERE. THE
POCONOS MAY BE TOO WARM.
SUNDAY AND SUNDAY NIGHT WE WILL BE UNDER THE UPPER LEVEL LOW AS IT
MOVES SE BEHIND THE COASTAL SFC NOREASTER. COLD AIR ADVECTION AND
A WEAK FLOW OFF THE GREAT LAKES WILL MEAN WIDESPREAD LIGHT SNOW
SHWOERS SUNDAY TO SUNDAY NIGHT. THE QUESTION IS WHEN IT WILL END.
FOR NOW HAVE IT ENDING SUN NGT BUT IT COULD CONTINUE INTO MONDAY.
BY MONDAY NIGHT SFC HIGH PRESSURE IS OVER THE CWA WITH AN UPPER
LEVEL RIDGE JUST UPSTREAM SO LOW CLOUDS AND SNOW SHOWERS WILL
TAPER OFF SUN NGT TO MON. WITH THE NW FLOW AND LAKE ENHANCEMENT
AND NEARNESS TO THE UPPER LEVEL LOW THE NRN COUNTIES COULD GET A
FEW INCHES AGAIN.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
140 PM UPDATE...
LONG TERM STARTS OFF WITH AN ACTIVE PATTERN. UL SYSTEM CURRENTLY
SLAMMING INTO THE PACIFIC NORTHWEST WL DIVE SOUTH AND CLOSE OFF ACRS
THE CNTRL PLAINS BY EARLY NEXT WEEK. AS IT CROSSES THE ROCKIES IT WL
UNDERGO LEE-SIDE CYCLOGENESIS AND INDUCE SFC LOW DVLPMNT ON MONDAY
WHICH WL TRANSLATE UP TWD CWA BY MID-WEEK. HOW QUICKLY IT IS ABLE TO
SPREAD PCPN UP INTO FA RMNS THE QUESTION WITH MED RANGE MODELS
HOLDING ONTO DRY AIR WITH H5 RIDGE THRU 12Z TUESDAY. THUS HV DELAYED
INTRODUCING ANY POPS INTO NRN SXNS THRU THIS TIME WITH ONLY CHC
EXPECTED FM SRN TIER AND POINTS SOUTH MAINLY IN THE FORM OF LGT
SNOW.
PCPN OVRSPRDS AREA BY TUE THO HOW QUICKLY IT DOES SO RMNS UP IN THE
AIR AT THIS POINT. 00Z EURO IS MUCH SLOWER WITH PROGRESS AND KEEPS
IT OUT OF CWA THRU 18Z TUE AND THEN ONLY BRINGS IT INTO WRN AND SRN
HALF BY 00Z WED. 12Z GFS IS ABOUT 6 HRS QUICKER. THUS THINK THAT
LKLY POPS WL BE THE WAY TO GO FOR THE ENTIRE PD ON TUESDAY WITH
HIGHER LKLYS ACRS THE SOUTH AND 55 POPS CONFINED TO NRN AND ERN
ZONES FOR CONTINUITY`S SAKE AND IN AGREEMENT WITH SURROUNDING
OFFICES. STILL PLENTY OF TIME TO WORK OUT THE DETAILS LATER. AS FOR
PTYPE, GFS CONTS TO BRING IN WRMR H8 TEMPS AS IT HAS DONE ALL WINTER
LONG AND EURO KEEPS H8 TEMPS BLO 0C. THUS HV CONTD WITH A RAIN/SNOW
MIX WRDNG FOR TUESDAY.
H5 LOW RIDES WEST OF CWA UP THE GREAT LKS TUE NGT INTO WED AND TRIES
TO TRANSFER ENERGY OFF THE COAST WITH SFC LOW RIDING UP FM THE SERN
U.S., BUT MAIN UL LOW DEEPENS TO OUR WEST AS ENERGY IS PROGGED TO
DIVE INTO THE BASE OF THE TROF ON WED FM THE SRN PLAINS. AS OF NOW
ENERGY TRANSFER DOES NOT APPEAR TO HAPPEN BUT THAT CUD ALWAYS CHG.
CHC POPS WL CONT THRU RMNDR OF THE WEEK AS UL LOW CLOSES OFF EAST OF
THE MS VLY. TEMPS WL BE FAIRLY STEADY WITH HIGHS IN THE MID-30S
UNDER EXTENSIVE CLD CVR. OVRNGT LOWS WL DROP THRU THE END OF THE
WEEK INTO THE 20S AS NRLY FLOW BRINGS IN CLD AIR.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
06Z UPDATE...
COMPLICATED AVIATION FORECAST DURING THIS TAF PERIOD...WITH REGION
IN MOIST FEED BETWEEN DEVELOPING LOW AROUND THE MID ATLANTIC
COAST...AND ANOTHER LOW IN THE NORTHERN GREAT LAKES. LOW END VFR
TO MVFR CIGS...COURTESY OF SHALLOW MOISTURE WHICH WILL
OCCASIONALLY YIELD PATCHY FREEZING DRIZZLE KAVP-KBGM-KELM LATER
THIS MORNING...BRIEF IFR CIG ALSO NOT OUT OF THE QUESTION LATER
THIS MORNING FOR KBGM /AFTER 12Z/. CIGS GENERALLY STAY IN MVFR
CATEGORY WITH LIGHT RAIN OR DRIZZLE DURING THE DAY CAUSING MVFR
VIS AS OCCLUDED FRONT PASSES OVERHEAD WITH CONTINUED SHALLOW
MOISTURE. BEHIND OCCLUDED FRONT TONIGHT...SATURATED LAYER GETS
SQUEEZED BELOW LOWERING INVERSION AND IFR CIGS MAY IMPACT MOST
TERMINALS. FREEZING DRIZZLE MAY ALSO RE-ENTER THE PICTURE.
.OUTLOOK...
LATE SAT NGT...MVFR/IFR IN MIXED PCPN.
SUN...VFR...MAYBE MVFR IN NY WITH LAKE ENHANCED SNOW SHOWERS.
MON...VFR.
TUE...MVFR/IFR IN RAIN AND/OR SNOW.
WED...MVFR IN LAKE ENHANCED SNOW SHOWERS.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...RRM/TAC
NEAR TERM...HEDEN/RRM/TAC
SHORT TERM...TAC
LONG TERM...PVN
AVIATION...MDP
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
330 AM EST SAT FEB 23 2013
.SYNOPSIS...
A STORM SYSTEM WILL BRING MODERATE RAIN TODAY FOLLOWED BY DRY HIGH
PRESSURE BUILDING IN ON SUNDAY. MOISTURE INCREASES AGAIN ON
MONDAY WITH SOME RAIN EXPECTED MONDAY NIGHT INTO TUESDAY AS
ANOTHER SYSTEM MOVES UP THE COAST. SLIGHTLY COOL WEATHER WILL
FOLLOW FOR THE LATTER PART OF NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 3 AM SATURDAY...A WIDESPREAD SIGNIFICANT RAINFALL EVENT IS
UNFOLDING ACROSS THE FORECAST AREA AS A SERIES OF WEAK WAVES OF LOW
PRESSURE MOVE UP THE COAST ALONG A FRONT. THE RISK FOR WET WEATHER
WILL COME TO AN END TONIGHT...VERY LATE AT THE COAST. PRECIPITABLE
WATER VALUES WILL PEAK BETWEEN 1.5 AND 1.75 INCHES THIS
MORNING...THROUGH MIDDAY. TOTAL RAINFALL AMOUNTS WITH THIS EVENT
WILL REACH 1 TO 2 INCHES WITH SOME AREAS RECEIVING AS MUCH AS 3
INCHES.
THE CHARACTER OF THE PRECIPITATION WILL MAINLY BE STRATIFORM RAIN.
HOWEVER...THE FRONT...JUST OFFSHORE MAY MEANDER ONTO THE COAST AHEAD
OF THE NEXT WAVE OF LOW PRESSURE MOVING UP THE SOUTHEAST COAST THIS
MORNING. THEREFORE...WILL INCLUDE CONVECTIVE SHOWERS AND AN ISOLATED
THUNDERSTORM. THE THUNDERSTORMS WILL BE ELEVATED AS THE AIRMASS WILL
REMAIN STABLE NEAR THE SURFACE.
A MID-LEVEL TROUGH WILL FINALLY KICK THE FRONT FAR ENOUGH E SO THAT
THE RISK FOR RAIN WILL COME TO AN END DURING THE OVERNIGHT HOURS.
HIGH PRESSURE CENTERED ACROSS NEW ENGLAND WILL WEDGE UPSTREAM OF THE
FRONTAL SYSTEM...ACTING NOT ONLY TO STABILIZE THE LOW-LEVELS...BUT
TO REINFORCE THE COOL AIR IN THE LOW-LEVELS. SO WHILE WARMER AND
MUCH MORE MOIST AIR STREAMS IN ON INCREASING WSW WINDS ALOFT...BELOW
ABOUT 3-4 KFT IT WILL BE COOL AND STABLE. RAIN FALLING INTO THIS
ENVIRONMENT WILL KEEP THE INVERSION LOCKED IN. THIS WILL ENSURE A
CLOUDY DAY. THE FURTHER INLAND YOU TRAVEL...THE LOWER AND STRONGER
WILL BE THIS INVERSION. THUS...HIGHS ACROSS INLAND AREAS WILL ONLY
REACH THE UPPER 40S TO LOWER 50S...COOLEST ALONG AND W OF INTERSTATE
95. ON THE COAST...IN CLOSEST PROXIMITY TO THE MEANDERING FRONT...
TEMPS WILL BE MORE OF A CHALLENGE. AT THIS TIME...EXPECT 60 DEG TO
BE IN REACH ACROSS MOST COASTAL LOCATIONS...HIGHEST DOWN AROUND
GEORGETOWN AND UP ACROSS THE CAPE FEAR REGION.
FOG WILL LIKELY PLAGUE MOST AREAS TODAY GIVEN THE STABLE LOW LAYERS
AND NEAR SATURATED ENVIRONMENT. DO NOT EXPECT DENSE FOG...JUST LOW
VISIBILITIES...AROUND A MILE AT TIMES IN RAIN AND FOG. ALONG THE
COAST...SEA FOG MAY BLEED ONTO THE COAST...ESPECIALLY THIS MORNING
AHEAD OF THE NEXT WAVE OF LOW PRESSURE.
TONIGHT...DRIER AIR WILL BE SLOW TO BUILD INTO THE EASTERN
CAROLINAS. NEARLY SATURATED GROUND AND LIGHT WINDS AT THE SURFACE
SHOULD ALLOW WIDESPREAD STRATUS TO PERSIST FOR MUCH OF THE NIGHT. IN
ADDITION...
DO EXPECT FOG TO ENVELOP THE AREA AND THERE COULD BE AREAS OF DENSE
FOG...ESPECIALLY LATE AT NIGHT. WE WILL CONTINUE TO MONITOR THE
PROSPECTS FOR DENSE FOG TONIGHT. DIURNAL RANGE WILL BE ESPECIALLY
SMALL INLAND WITH LOWS TONIGHT MAINLY IN THE LOWER TO MID 40S. AT
THE COAST...UPPER 40S TO AROUND 50 DEG WILL BE MORE COMMON.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 3 AM SATURDAY...ZONAL FLOW AND A DRY COLUMN WITH ONLY VERY
PALTRY COLD AIR ADVECTION ON SUNDAY TO BRING PLENTY OF SUNSHINE AND
FAIRLY SEASONABLE TEMPERATURES. SURFACE HIGH WILL BE BUILDING INTO
THE OHIO VALLEY AND EVENTUALLY PA WHILE DIVING UPPER SYSTEM SPINS UP
A LOW OVER NRN TX. AS BOTH TRANSLATE EASTWARD SUNDAY NIGHT A LONG
WEST-EAST FRONT WILL DEVELOP ACRS THE LOWER MS VALLEY AND GULF
STATES. WARM ADVECTION RAIN SHOULD BREAK OUT ACROSS THE SOUTHEAST
ALBEIT IN FAIRLY LIGHT AMOUNTS INITIALLY. RAINFALL CHANCES AND
INTENSITY SHOULD INCREASE LATE MONDAY INTO MONDAY NIGHT AS WEAK
TRIPLE POINT LOW DEVELOPS AND APPROACHES. THE UPPER WAVE DRIVING
THIS SYSTEM IS STRONGER AND FURTHER SOUTH THAN THE SYSTEM RELATED TO
THE NEAR TERM..WHICH HAS LARGELY FAILED TO BE THE PROLIFIC RAIN
PRODUCER THAT MODELS HAD ADVERTISED FOR DAYS. THE POSITION OF THIS
FORTHCOMING UPPER LOW MAY BETTER SUPPORT A RAINY SCENARIO.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 3 AM SATURDAY...VERY HIGH RAINFALL CHANCES TO START THE PERIOD
AND AN APPRECIABLE QPF EVENT MAY BE IN THE PROCESS OF WINDING DOWN.
DEEP CUTOFF LOW OVER WRN TN WITH A WEAK TRIPLE POINT LOW SLIDING NNE
UP THE CAROLINA COASTLINE. TEMPS WITH THIS ONE A TOUGH CALL AS NW TO
SE GRADIENT IN HIGHS TUESDAY MAY BE CONSIDERABLE. STRONG LOW LEVEL
JETTING AND SOME MID LEVEL HEIGHT FALLS TO SERVE AS DEEP LIFT BUT BY
LATE MORNING THE SYSTEM SWINGS THROUGH LEADING TO STRONG DRY AIR
ADVECTION. WEDNESDAY APPEARS TO BE A TRANSITIONAL DAY WITH A LITTLE
WRAP AROUND MOISTURE ASSOCIATED WITH STRONG TRAILING ENERGY KICKING
OUT THE TN CUTOFF BUT ALSO LEADING TO DEEP LONGWAVE TROUGHINESS IN
THE EAST. AS THIS FEATURE BECOMES INCREASINGLY SLOW TO PROGRESS EAST
FOR THE REST OF THE PERIOD PROLONGED COLD AIR ADVECTION WILL KEEP
TEMPS BELOW CLIMO BY ABOUT A CATEGORY.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
AS OF 06Z...EXPECT WIDESPREAD IFR/LIFR ACROSS THE TERMINALS
THROUGH SATURDAY DUE TO LOWERED CIGS AND REDUCED VISIBILITIES IN
RAIN AND FOG.
LOWERED CIGS WITH AREAS OF RA AND REDUCED VISIBILITIES DUE TO FOG
CONTINUE TO BE WIDESPREAD ACROSS THE AREA...WITH NORTHEAST WINDS AOB
6 KTS. EXPECT MAINLY LIFR CONDITIONS TO CONTINUE OVERNIGHT AND
MODELS ARE IN GOOD AGREEMENT.
RAIN WILL INCREASE THROUGH THE MORNING HOURS...WHICH WILL ALSO
CONTRIBUTE TO REDUCED VISIBILITIES. THOUGH RAIN WILL TAPER OFF INTO
SATURDAY EVENING...GIVEN CURRENT FCST SOUNDINGS AND TIME-HEIGHT
ANALYSIS...PROJECT IFR CONDITIONS DUE TO LOWERED CIGS AND FOG TO
PERSIST THROUGH THE TAIL END OF THE FORECAST PERIOD.
NE WIND MAY BRIEFLY BECOME SSW ALONG THE COAST THIS MORNING AS
OFFSHORE FRONT NEARS...BUT EXPECT NNE WINDS TO HOLD ACROSS KFLO AND
KLBT. WINDS WILL BECOME WSW THROUGHOUT BY EVENING.
EXTENDED OUTLOOK...EXPECT MVFR/IFR CONDITIONS OVERNIGHT SATURDAY...
BECOMING VFR SUNDAY. RAIN REDEVELOPING MONDAY ENDING TUESDAY
MORNING. OTHERWISE EXPECT VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 PM FRIDAY...POSITIONING OF THE COASTAL FRONT WILL BE
THE MAIN FOCUS AND PROBLEM OVERNIGHT INTO SATURDAY. BORDERLINE SCA
THRESHOLDS WARRANT THE CONTINUATION OF THE SCA INTO SATURDAY.
COASTAL FRONT REMAINS JUST OFFSHORE...JUST BEYOND THE OUTER WATERS
OF THE ILM COASTAL WATERS. LATEST WINDS AND SEAS AT 41013 AND
41037 BUOYS ARE SE 15 TO 20 KT WITH 5 FT SEAS. LATEST WINDS AND
SEAS AT 41110...41038 AND 41024 BUOYS ARE NE TO ENE 10 TO 20 KT
WITH SEAS 3 TO 5 FT. SCA CONDITIONS SHOULD BE REALIZED OVERNITE
AS THE SFC PG FURTHER TIGHTENS...AND THE COASTAL FRONT GETS PULLED
CLOSER TO THE IMMEDIATE COAST IN ADVANCE OF THE LOW APPROACHING
FROM THE SW.
THE LATEST HRRR SFC WIND FIELDS KEEP THE COASTAL FRONT OVER THE
WATERS RATHER THAN BRINGING IT ONSHORE. HAVE GEARED TOWARD THIS
SCENARIO...AND HAVE NOW INDICATED THE COASTAL FRONT TO PARTIALLY
MOVE ACROSS THE COASTAL WATERS OVERNITE INTO SAT. AS A RESULT...
HAVE AD-LIBBED THE CURRENT CWF TEXT TO INDICATE THE DIFFERENCES
IN BOTH WINDS AND SEAS IN THE NEAR SHORE...0-10 NM OUT...AND THE
OUTER WATERS...10-20 NM OUT. HAVE ALSO INDICATED ISOLATED
CONVECTION AFTER MIDNIGHT INTO THE DAYLIGHT HRS OF SAT DUE TO
DYNAMICS FROM IMPULSES ALOFT INTERACTING WITH THE COASTAL FRONT.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 3 AM SATURDAY...EARLY SUNDAY BRINGS A NORTHWEST WIND AS COLD
FRONT MOVES FURTHER OFFSHORE AND LOW PRESSURE SLIDES UP OFF OF NEW
ENGLAND COAST. A LITTLE BACKSWELL FROM THIS SYSTEM COMBINED WITH THE
WIND WAVE WILL GENERATE ABOUT A 2 TO 4 FT PREDOMINANT SEA STATE.
LATER SUNDAY HIGH PRESSURE PROGRESSES EASTWARD CUTTING WELL NORTH OF
THE REGION LOCALLY VEERING THE WINDS. FLOW WILL MORE OR LESS STAY
NORTHEASTERLY OR EASTERLY THROUGH MONDAY AS THE HIGH SLOWS AND A
STORM SYSTEM DEEPENS ACROSS THE LOWER MS VALLEY WHILE APPROACHING.
CONDITIONS THEN DETERIORATE MONDAY NIGH AS THE WARM FRONT APPROACHES
BOTH VEERING AND INCREASING THE FLOW TO WHERE AND ADVISORY WILL
LIKELY BE CALLED FOR.
LONG TERM /TUESDAY THROUGH WEDNESDAY/...
AS OF 3 AM SATURDAY...VERY UNSETTLED TO START THE PERIOD AS A TRIPLE
POINT LOW PRESSURE SLIDES UP THE COASTAL PLAIN. LOCAL ENHANCEMENT OF
THE SOUTHERLY WINDS WILL PUSH WIND AND SEAS MORE SOLIDLY INTO SMALL
CRAFT REALM COMPARED TO THE END OF THE SHORT TERM PERIOD BUT THE
MILD AIR FLOWING OVER THE COOLER SSTS SHOULD PROBABLY PRECLUDE
SUFFICIENT VERTICAL MIXING TO SUPPORT SUSTAINED GALE FORCE WINDS.
JUST THE SAME GUSTINESS MAY NOT BE A BIG FACTOR BUT THERE IS SOME
UNCERTAINTY AND FUTURE FORECASTS WILL HAVE TO ADDRESS THIS ISSUE.
COLD FRONT SWEEPS ACROSS LATER IN THE DAY BEHIND THIS SYSTEM SHARPLY
VEERING THE FLOW WHILE ALSO HERALDING A DECREASING TREND IN WIND AND
SEAS ALBEIT POSSIBLY A SLOW ONE.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...DENSE FOG ADVISORY UNTIL NOON EST TODAY FOR AMZ254-256.
SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS EVENING FOR AMZ250-
252.
&&
$$
SYNOPSIS...MBB
NEAR TERM...RJD
SHORT TERM...MBB
LONG TERM...MBB
AVIATION...RJD/SGL
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1234 AM EST SAT FEB 23 2013
.SYNOPSIS...
RAIN WILL PERSIST INTO SATURDAY NIGHT. HIGH PRESSURE WILL BRING DRY
AIR ON SUNDAY LASTING INTO EARLY MONDAY. ANOTHER ROUND OF RAINFALL
WILL OCCUR MONDAY INTO TUESDAY. THE MIDDLE TO THE END OF NEXT WEEK
WILL FEATURE DRY AND COOL CONDITIONS.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
AS OF 1045 PM FRIDAY...CONTINUED LACK OF RADAR ECHOES ACROSS THE
FA AT THE MOMENT. THE RADAR RETURNS FOR THE MOST PART OVER LAND
WERE NOT REACHING THE GROUND VIA SFC OBSERVATIONS. THINKING
REMAINS THAT THE FA WILL FILL IN WITH LIGHT TO MODERATE STRATIFORM
TYPE RAINS AFTER MIDNIGHT...MAINLY TOWARD DAYBREAK SAT. AS A
RESULT...OVERNITE AND DAYLIGHT SAT POPS HAVE BEEN ADJUSTED.
LATEST PROGS KEEP THE COASTAL FRONT ALONG THE IMMEDIATE
COAST...WITH VERY LITTLE INLAND MOVEMENT. IN FACT...LATEST HRRR
PROGGED SFC WIND FIELD KEEPS A NORTHERLY COMPONENT IN THE WINDS
ACROSS THE CWA OVERNITE INTO SAT. TONIGHTS MINS...NOT THE 24 HR
MIN...WILL LIKELY OCCUR AROUND OR JUST AFTER MIDNIGHT...FOLLOWED
BY A STEADY OR EVEN A SLOW/SLIGHT RISE IN TEMPS DURING THE PRE-
DAWN HRS ESPECIALLY ALONG THE IMMEDIATE COAST. WEAK IMPULSES
WITHIN SW-WSW FLOW ALOFT MAY PROVIDE ENOUGH DYNAMICS TO AID THE
DEVELOPMENT OF ISOLATED CONVECTION ALONG THE COASTAL FRONT.
HAVE INDICATED ISOLATED THUNDER FOR JUST THE COASTAL
COUNTIES DURING THE PRE-DAWN SAT HRS.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
AS OF 330 PM FRIDAY...WET START TO THE WEEKEND WITH A COMPLEX
FRONTAL SYSTEM MOVING ACROSS THE COASTAL CAROLINAS. A SERIES OF
STRONG UPPER SHORT WAVES MOVING ACROSS EASTERN CONUS WILL POWER THE
VERY PROGRESSIVE WEATHER PATTERN WE HAVE BEEN EXPERIENCING LATELY.
RAIN WILL BE ONGOING SATURDAY MORNING WITH ALL GUIDANCE IN GOOD
AGREEMENT THAT 100 POPS ARE MOST APPROPRIATE TO START OFF THE DAY.
MODEL SOUNDINGS SHOW A DEEP...MOIST COLUMN WITH P/W VALUES IN
EXCESS OF 1.50 INCHES AND ENOUGH ISENTROPIC LIFT TO WRING OUT AT
LEAST MODERATE RAINFALL THROUGH THE MORNING HOURS. SIGNIFICANT
RAIN COULD EXTEND WELL INTO THE AFTERNOON HOURS...WITH A LESSER
SHORTWAVE POSSIBLY KICKING OFF ANOTHER ROUND OF HEAVIER
PRECIPITATION IN THE EVENING HOURS. MIGRATORY HIGH PRESSURE PUSHES
ENTIRE SYSTEM OFFSHORE OVERNIGHT...WITH ANY RESIDUAL LIGHT PRECIP
HAVING SHUT DOWN BY AROUND DAYBREAK ON SUNDAY.
THE HIGH BUILDING IN ON SUNDAY WILL BRIEFLY USHER IN A MUCH DRYER
AIRMASS ALTHOUGH COLD ADVECTION WILL BE ON THE WEAK SIDE. MODEL
SOUNDINGS SUGGEST A SUNNY DAY...WITH INCREASING CIRRUS OVERNIGHT
AS A WARM FRONT APPROACHES FROM THE SOUTH.
TEMPERATURES MAY BE TRICKY SIDE ON SATURDAY DUE TO FRONTAL
PLACEMENT AND EXTENSIVE PRECIPITATION. MODEL CONSENSUS SUGGESTS A
NEARLY 10 DEGREE TEMPERATURE SPREAD BETWEEN THE COASTAL AND INLAND
REGIONS...WITH MAXIMUM TEMPERATURES OF AROUND 50 WELL INLAND...AND
UPPER 50S ALONG THE COAST. AMPLE SUN AND POSSIBLE DOWNSLOPING ON
SUNDAY WILL BRING MAXIMUM TEMPERATURES UP INTO THE MID 60S MOST
PLACES. NO WORRIES ABOUT FREEZING TEMPERATURES...WITH LOWS IN THE
40S MOST PLACES BOTH NIGHTS.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 330 PM FRIDAY...HIGH PRESSURE EXTENDING DOWN FROM SYSTEM OVER
THE GREAT LAKES MAY REMAIN WEDGED IN THROUGH INLAND CAROLINAS AS
DEVELOPING LOW PRESSURE MAKES ITS WAY UP FROM THE GULF COAST MONDAY
INTO TUESDAY. LOOKS LIKE SHALLOW NORTHEAST FLOW AT THE SURFACE WILL
BE OVERRUN BY INCREASING SOUTHERLY FLOW ALOFT THROUGH LATE MONDAY
INTO TUES MORNING. EXPECT CLOUDS TO THICKEN EARLY MONDAY AND PCP TO
SPREAD NORTH THROUGH THE DAY. MAY SQUEEZE OUT A DRY DAY ACROSS NORTH
CAROLINA. THE PARENT LOW TO THIS SYSTEM WILL MOVE UP THROUGH THE MID
WEST INTO THE GREAT LAKES ON TUESDAY. THIS WILL HELP TO ERODE THE
WEDGE AND PULL THE LOW OVER THE SOUTHEAST TO THE NORTH BY TUES AFTN.
THEREFORE EXPECT BEST ISENTROPIC LIFT THROUGH LATE MON INTO MON
NIGHT AND TAPERING OFF THROUGH TUES MORNING. MAY SEE DECENT QPF
THROUGH MON INTO EARLY TUES.
BY TUES AFTN WINDS WILL SHIFT AROUND TO THE SW TO W ON BACK END OF
LOW. EXPECT DRIER AIR TO MAKE ITS WAY IN AT THIS TIME. WINDS ALOFT
WILL REMAIN W-SW AS PARENT LOW CUTS OFF AND CONTINUES TO SPIN OVER
THE UPPER GREAT LAKES WITH BROAD TROUGH EXTENDING DOWN ACROSS THE
EASTERN CONUS THROUGH MID WEEK. OVERALL WEAK HIGH PRESSURE WILL TAKE
HOLD OVER AREA THROUGH THE REST OF THE PERIOD WITH GENERALLY DRY
FORECAST TUES NIGHT THROUGH FRI. GFS SHOWS ANOTHER SHORTWAVE RIDING
ACROSS THE BASE OF THE TROUGH THROUGH NORTH CAROLINA WED NIGHT INTO
THURS. THIS MAY PRODUCE SOME CLOUDS AND PCP BUT FOR NOW WILL KEEP
MAIN EFFECTS FROM THIS TO OUR NORTH. WITH TROUGH HANGING OVER
AREA...CAN NOT RULE OUT THE CHC OF CLOUDS OR PCP AS MINOR
PERTURBATIONS MOVE THROUGH BUT FOR NOW...NOT LOOKING AT ANY MAJOR
EFFECTS.
AS FOR TEMPS...COOLER DAY EXPECTED ON MONDAY WITH TEMPS IN THE 50S
IN COOL WEDGE...ESPECIALLY INLAND AREAS. AS WINDS COME AROUND WARMER
AND MOISTER AIR COMBINED WITH CLOUDS WILL KEEP TEMPS UP MON NIGHT
AND THEN WILL SEE WARMER MORE SEASONABLE TEMPS THROUGH MID WEEK IN
S-SW FLOW. FRI MAY COOL OFF AS NW FLOW DEVELOPS ON BACK END OF
DEPARTING LOW.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
AS OF 06Z...EXPECT WIDESPREAD IFR/LIFR ACROSS THE TERMINALS
THROUGH SATURDAY DUE TO LOWERED CIGS AND REDUCED VISIBILITIES IN
RAIN AND FOG.
LOWERED CIGS WITH AREAS OF RA AND REDUCED VISIBILITIES DUE TO FOG
CONTINUE TO BE WIDESPREAD ACROSS THE AREA...WITH NORTHEAST WINDS AOB
6 KTS. EXPECT MAINLY LIFR CONDITIONS TO CONTINUE OVERNIGHT AND
MODELS ARE IN GOOD AGREEMENT.
RAIN WILL INCREASE THROUGH THE MORNING HOURS...WHICH WILL ALSO
CONTRIBUTE TO REDUCED VISIBILITIES. THOUGH RAIN WILL TAPER OFF INTO
SATURDAY EVENING...GIVEN CURRENT FCST SOUNDINGS AND TIME-HEIGHT
ANALYSIS...PROJECT IFR CONDITIONS DUE TO LOWERED CIGS AND FOG TO
PERSIST THROUGH THE TAIL END OF THE FORECAST PERIOD.
NE WIND MAY BRIEFLY BECOME SSW ALONG THE COAST THIS MORNING AS
OFFSHORE FRONT NEARS...BUT EXPECT NNE WINDS TO HOLD ACROSS KFLO AND
KLBT. WINDS WILL BECOME WSW THROUGHOUT BY EVENING.
EXTENDED OUTLOOK...EXPECT MVFR/IFR CONDITIONS OVERNIGHT SATURDAY...
BECOMING VFR SUNDAY. RAIN REDEVELOPING MONDAY ENDING TUESDAY
MORNING. OTHERWISE EXPECT VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 PM FRIDAY...POSITIONING OF THE COASTAL FRONT WILL BE
THE MAIN FOCUS AND PROBLEM OVERNIGHT INTO SATURDAY. BORDERLINE SCA
THRESHOLDS WARRANT THE CONTINUATION OF THE SCA INTO SATURDAY.
COASTAL FRONT REMAINS JUST OFFSHORE...JUST BEYOND THE OUTER WATERS
OF THE ILM COASTAL WATERS. LATEST WINDS AND SEAS AT 41013 AND
41037 BUOYS ARE SE 15 TO 20 KT WITH 5 FT SEAS. LATEST WINDS AND
SEAS AT 41110...41038 AND 41024 BUOYS ARE NE TO ENE 10 TO 20 KT
WITH SEAS 3 TO 5 FT. SCA CONDITIONS SHOULD BE REALIZED OVERNITE
AS THE SFC PG FURTHER TIGHTENS...AND THE COASTAL FRONT GETS PULLED
CLOSER TO THE IMMEDIATE COAST IN ADVANCE OF THE LOW APPROACHING
FROM THE SW.
THE LATEST HRRR SFC WIND FIELDS KEEP THE COASTAL FRONT OVER THE
WATERS RATHER THAN BRINGING IT ONSHORE. HAVE GEARED TOWARD THIS
SCENARIO...AND HAVE NOW INDICATED THE COASTAL FRONT TO PARTIALLY
MOVE ACROSS THE COASTAL WATERS OVERNITE INTO SAT. AS A RESULT...
HAVE AD-LIBBED THE CURRENT CWF TEXT TO INDICATE THE DIFFERENCES
IN BOTH WINDS AND SEAS IN THE NEAR SHORE...0-10 NM OUT...AND THE
OUTER WATERS...10-20 NM OUT. HAVE ALSO INDICATED ISOLATED
CONVECTION AFTER MIDNIGHT INTO THE DAYLIGHT HRS OF SAT DUE TO
DYNAMICS FROM IMPULSES ALOFT INTERACTING WITH THE COASTAL FRONT.
SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 330 PM FRIDAY...COMPLEX FRONTAL SYSTEM OVER THE COASTAL
CAROLINAS WILL BRING SOUTH TO SOUTHWEST WINDS OF 15 TO 20 KTS AND 4
TO 6 FT SEAS TO THE WATERS SATURDAY MORNING...WITH CONDITIONS
GRADUALLY IMPROVING THROUGH THE DAY. FRONTAL SYSTEM WILL PUSH
OFFSHORE OVERNIGHT...WITH WINDS TURNING OFFSHORE AFTER MIDNIGHT.
RESULTING LIMITED FETCH WILL ALLOW SEAS TO DROP BACK INTO THE 2 TO 4
FT RANGE OVERNIGHT. RAINFALL ON SATURDAY MAY BE HEAVY AT
TIMES...RESTRICTING VISIBILITY SIGNIFICANTLY.
FAIRLY BENIGN3CONDITIONS WILL CONTINUE INTO SUNDAY WITH SEAS
MAINLY IN THE 2 TO 4 FT RANGE AND LIGHT WINDS DURING THE DAYTIME
HOURS. WINDS WILL VEER TO THE NE OVERNIGHT AS A WARM FRONT
APPROACHES FROM THE SOUTH...INCREASING TO 10 TO 15 KTS BY DAYBREAK
ON MONDAY.
LONG TERM /MONDAY THROUGH WEDNESDAY/...
AS OF 330 PM FRIDAY...GRADIENT WILL TIGHTEN THROUGH MONDAY AS HIGH
PRESSURE EXTENDING DOWN FROM THE GREAT LAKES SHIFTS EAST WHILE LOW
PRESSURE SYSTEM MAKES ITS WAY UP FROM THE GULF COAST. EXPECT N-NE
WINDS EARLY MONDAY SHIFTING AROUND AND INCREASING AS WARM
FRONT/COASTAL TROUGH PUSHES INLAND BY TUESDAY. SEAS AROUND 2 TO 3 FT
MON MORNING WILL INCREASE THROUGH THE DAY WITH INCREASING NE TO E
FLOW REACHING UP TO A SOLID 20 KTS THROUGH MON NIGHT. THIS WILL PUSH
SEAS UP ABOVE SCA THRESHOLDS BY MIDNIGHT AND REMAINING 6 TO 8 FT IN
OUTER WATERS AND 4 TO 6 FT NEAR SHORE THROUGH TUES MORNING.
AS THE LOW LIFTS OFF TO THE NORTH LATE TUESDAY THE WINDS WILL VEER
AROUND TO THE W-SW REMAINING THAT WAY THROUGH MID WEEK. THE
WEAKENING OFF SHORE FLOW WILL ALLOW SEAS TO SUBSIDE BELOW SCA
THRESHOLDS BY LATE TUES DROPPING FURTHER TO 2 TO 4 FT THROUGH
WEDNESDAY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 10 AM EST SATURDAY FOR AMZ254-256.
SMALL CRAFT ADVISORY UNTIL 6 PM EST SATURDAY FOR AMZ250-252.
&&
$$
NEAR TERM...DCH
SHORT TERM...REK
LONG TERM...RGZ
AVIATION...SGL/RJD
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1112 PM EST FRI FEB 22 2013
.SYNOPSIS...
ISOLATED AREAS OF LIGHT RAIN WILL CONTINUE THIS AFTERNOON.
MODERATE TO HEAVY RAIN IS EXPECTED FOR THE OVERNIGHT HOURS AND
INTO SATURDAY. HIGH PRESSURE WILL BRING IN DRY AIR ON SUNDAY
LASTING INTO EARLY MONDAY. ANOTHER ROUND OF RAINFALL WILL OCCUR
MONDAY INTO TUESDAY. THE MIDDLE TO THE END OF NEXT WEEK WILL
FEATURE DRY AIR AND A COOLING TREND.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
AS OF 1045 PM FRIDAY...CONTINUED LACK OF RADAR ECHOES ACROSS THE
FA AT THE MOMENT. THE RADAR RETURNS FOR THE MOST PART OVER LAND
WERE NOT REACHING THE GROUND VIA SFC OBSERVATIONS. THINKING
REMAINS THAT THE FA WILL FILL IN WITH LIGHT TO MODERATE STRATIFORM
TYPE RAINS AFTER MIDNIGHT...MAINLY TOWARD DAYBREAK SAT. AS A
RESULT...OVERNITE AND DAYLIGHT SAT POPS HAVE BEEN ADJUSTED.
LATEST PROGS KEEP THE COASTAL FRONT ALONG THE IMMEDIATE
COAST...WITH VERY LITTLE INLAND MOVEMENT. IN FACT...LATEST HRRR
PROGGED SFC WIND FIELD KEEPS A NORTHERLY COMPONENT IN THE WINDS
ACROSS THE CWA OVERNITE INTO SAT. TONIGHTS MINS...NOT THE 24 HR
MIN...WILL LIKELY OCCUR AROUND OR JUST AFTER MIDNIGHT...FOLLOWED
BY A STEADY OR EVEN A SLOW/SLIGHT RISE IN TEMPS DURING THE PRE-
DAWN HRS ESPECIALLY ALONG THE IMMEDIATE COAST. WEAK IMPULSES
WITHIN SW-WSW FLOW ALOFT MAY PROVIDE ENOUGH DYNAMICS TO AID THE
DEVELOPMENT OF ISOLATED CONVECTION ALONG THE COASTAL FRONT.
HAVE INDICATED ISOLATED THUNDER FOR JUST THE COASTAL
COUNTIES DURING THE PRE-DAWN SAT HRS.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
AS OF 3:30 PM FRIDAY...WET START TO THE WEEKEND WITH A COMPLEX
FRONTAL SYSTEM MOVING ACROSS THE COASTAL CAROLINAS. A SERIES OF
STRONG UPPER SHORT WAVES MOVING ACROSS EASTERN CONUS WILL POWER
THE VERY PROGRESSIVE WEATHER PATTERN WE HAVE BEEN EXPERIENCING
LATELY.
RAIN WILL BE ONGOING SATURDAY MORNING WITH ALL GUIDANCE IN GOOD
AGREEMENT THAT 100 POPS ARE MOST APPROPRIATE TO START OFF THE DAY.
MODEL SOUNDINGS SHOW A DEEP...MOIST COLUMN WITH P/W VALUES IN
EXCESS OF 1.50 INCHES AND ENOUGH ISENTROPIC LIFT TO WRING OUT AT
LEAST MODERATE RAINFALL THROUGH THE MORNING HOURS. SIGNIFICANT
RAIN COULD EXTEND WELL INTO THE AFTERNOON HOURS...WITH A LESSER
SHORTWAVE POSSIBLY KICKING OFF ANOTHER ROUND OF HEAVIER
PRECIPITATION IN THE EVENING HOURS. MIGRATORY HIGH PRESSURE PUSHES
ENTIRE SYSTEM OFFSHORE OVERNIGHT...WITH ANY RESIDUAL LIGHT PRECIP
HAVING SHUT DOWN BY AROUND DAYBREAK ON SUNDAY.
THE HIGH BUILDING IN ON SUNDAY WILL BRIEFLY USHER IN A MUCH DRYER
AIRMASS ALTHOUGH COLD ADVECTION WILL BE ON THE WEAK SIDE. MODEL
SOUNDINGS SUGGEST A SUNNY DAY...WITH INCREASING CIRRUS OVERNIGHT
AS A WARM FRONT APPROACHES FROM THE SOUTH.
TEMPERATURES MAY BE TRICKY SIDE ON SATURDAY DUE TO FRONTAL
PLACEMENT AND EXTENSIVE PRECIPITATION. MODEL CONSENSUS SUGGESTS A
NEARLY 10 DEGREE TEMPERATURE SPREAD BETWEEN THE COASTAL AND INLAND
REGIONS...WITH MAXIMUM TEMPERATURES OF AROUND 50 WELL INLAND...AND
UPPER 50S ALONG THE COAST. AMPLE SUN AND POSSIBLE DOWNSLOPING ON
SUNDAY WILL BRING MAXIMUM TEMPERATURES UP INTO THE MID 60S MOST
PLACES. NO WORRIES ABOUT FREEZING TEMPERATURES...WITH LOWS IN THE
40S MOST PLACES BOTH NIGHTS.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 3:30 PM FRIDAY...HIGH PRESSURE EXTENDING DOWN FROM SYSTEM OVER
THE GREAT LAKES MAY REMAIN WEDGED IN THROUGH INLAND CAROLINAS AS
DEVELOPING LOW PRESSURE MAKES ITS WAY UP FROM THE GULF COAST
MONDAY INTO TUESDAY. LOOKS LIKE SHALLOW NORTHEAST FLOW AT THE
SURFACE WILL BE OVERRUN BY INCREASING SOUTHERLY FLOW ALOFT THROUGH
LATE MONDAY INTO TUES MORNING. EXPECT CLOUDS TO THICKEN EARLY
MONDAY AND PCP TO SPREAD NORTH THROUGH THE DAY. MAY SQUEEZE OUT A
DRY DAY ACROSS NORTH CAROLINA. THE PARENT LOW TO THIS SYSTEM WILL
MOVE UP THROUGH THE MID WEST INTO THE GREAT LAKES ON TUESDAY. THIS
WILL HELP TO ERODE THE WEDGE AND PULL THE LOW OVER THE SOUTHEAST
TO THE NORTH BY TUES AFTN. THEREFORE EXPECT BEST ISENTROPIC LIFT
THROUGH LATE MON INTO MON NIGHT AND TAPERING OFF THROUGH TUES
MORNING. MAY SEE DECENT QPF THROUGH MON INTO EARLY TUES.
BY TUES AFTN WINDS WILL SHIFT AROUND TO THE SW TO W ON BACK END OF
LOW. EXPECT DRIER AIR TO MAKE ITS WAY IN AT THIS TIME. WINDS ALOFT
WILL REMAIN W-SW AS PARENT LOW CUTS OFF AND CONTINUES TO SPIN OVER
THE UPPER GREAT LAKES WITH BROAD TROUGH EXTENDING DOWN ACROSS THE
EASTERN CONUS THROUGH MID WEEK. OVERALL WEAK HIGH PRESSURE WILL TAKE
HOLD OVER AREA THROUGH THE REST OF THE PERIOD WITH GENERALLY DRY
FORECAST TUES NIGHT THROUGH FRI. GFS SHOWS ANOTHER SHORTWAVE RIDING
ACROSS THE BASE OF THE TROUGH THROUGH NORTH CAROLINA WED NIGHT INTO
THURS. THIS MAY PRODUCE SOME CLOUDS AND PCP BUT FOR NOW WILL KEEP
MAIN EFFECTS FROM THIS TO OUR NORTH. WITH TROUGH HANGING OVER
AREA...CAN NOT RULE OUT THE CHC OF CLOUDS OR PCP AS MINOR
PERTURBATIONS MOVE THROUGH BUT FOR NOW...NOT LOOKING AT ANY MAJOR
EFFECTS.
AS FOR TEMPS...COOLER DAY EXPECTED ON MONDAY WITH TEMPS IN THE 50S
IN COOL WEDGE...ESPECIALLY INLAND AREAS. AS WINDS COME AROUND WARMER
AND MOISTER AIR COMBINED WITH CLOUDS WILL KEEP TEMPS UP MON NIGHT
AND THEN WILL SEE WARMER MORE SEASONABLE TEMPS THROUGH MID WEEK IN
S-SW FLOW. FRI MAY COOL OFF AS NW FLOW DEVELOPS ON BACK END OF
DEPARTING LOW.
&&
.AVIATION /04Z SATURDAY THROUGH WEDNESDAY/...
AS OF 00Z...WIDESPREAD MVFR/IFR THIS EVENING WILL GRADUALLY
DETERIORATE TO IFR/LIFR ACROSS THE ENTIRE AREA OVERNIGHT AND THROUGH
SATURDAY EARLY EVENING. CONDITIONS MAY IMPROVE TO MVFR TOWARDS THE END OF
THE TAF PERIOD.
LOWERED CIGS WITH AREAS OF -DZ AND REDUCED VISIBILITIES DUE TO FOG
ARE SPREAD ABOUT THE ENTIRE AREA THIS EVENING...WITH EAST-NORTHEAST
WINDS AOB 10 KTS. EXPECT CONDITIONS TO CONTINUE TO DETERIORATE INTO
THE EARLY OVERNIGHT HOURS TO IFR/LIFR...WITH MODELS IN GOOD
AGREEMENT. DRIER AIR WITHIN THE MID LEVELS HAS INHIBITED WIDESPREAD
RA/SHRA AS PREVIOUSLY ANTICIPATED...THUS HAVE OPTED TO ONLY INCLUDE
-DZ/VCSH FOR THE OVERNIGHT HOURS. SATURDAY MORNING...ANTICIPATE
IFR/LIFR TO CONTINUE WITH LOWERED CIGS AND AREAS OF FOG. RAIN
CHANCES WILL INCREASE AS WELL ON SATURDAY...WHICH WILL ALSO
CONTRIBUTE TO REDUCED VISIBILITIES. GIVEN CURRENT FCST SOUNDINGS AND
TIME-HEIGHT ANALYSIS...PROJECT THESE CONDITIONS TO CONTINUE THROUGH
SATURDAY EVENING...THOUGH COULD POTENTIALLY SEE CONDITIONS IMPROVE
TO MVFR BEFORE THE END OF VALID FORECAST. WINDS THROUGHOUT THE DAY
ON SATURDAY WILL GRADUALLY SHIFT TO GENERALLY SOUTH ALONG THE
COAST...WHILE PERSISTING NORTH-NORTHEAST INLAND.
EXTENDED OUTLOOK...EXPECT MVFR/IFR CONDITIONS SATURDAY NIGHT.
BECOMING VFR SUNDAY. RAIN REDEVELOPING MONDAY ENDING TUESDAY
MORNING. OTHERWISE EXPECT VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 PM FRIDAY...POSITIONING OF THE COASTAL FRONT WILL BE
THE MAIN FOCUS AND PROBLEM OVERNIGHT INTO SATURDAY. BORDERLINE SCA
THRESHOLDS WARRANT THE CONTINUATION OF THE SCA INTO SATURDAY.
COASTAL FRONT REMAINS JUST OFFSHORE...JUST BEYOND THE OUTER WATERS
OF THE ILM COASTAL WATERS. LATEST WINDS AND SEAS AT 41013 AND
41037 BUOYS ARE SE 15 TO 20 KT WITH 5 FT SEAS. LATEST WINDS AND
SEAS AT 41110...41038 AND 41024 BUOYS ARE NE TO ENE 10 TO 20 KT
WITH SEAS 3 TO 5 FT. SCA CONDITIONS SHOULD BE REALIZED OVERNITE
AS THE SFC PG FURTHER TIGHTENS...AND THE COASTAL FRONT GETS PULLED
CLOSER TO THE IMMEDIATE COAST IN ADVANCE OF THE LOW APPROACHING
FROM THE SW.
THE LATEST HRRR SFC WIND FIELDS KEEP THE COASTAL FRONT OVER THE
WATERS RATHER THAN BRINGING IT ONSHORE. HAVE GEARED TOWARD THIS
SCENARIO...AND HAVE NOW INDICATED THE COASTAL FRONT TO PARTIALLY
MOVE ACROSS THE COASTAL WATERS OVERNITE INTO SAT. AS A RESULT...
HAVE AD-LIBBED THE CURRENT CWF TEXT TO INDICATE THE DIFFERENCES
IN BOTH WINDS AND SEAS IN THE NEAR SHORE...0-10 NM OUT...AND THE
OUTER WATERS...10-20 NM OUT. HAVE ALSO INDICATED ISOLATED
CONVECTION AFTER MIDNIGHT INTO THE DAYLIGHT HRS OF SAT DUE TO
DYNAMICS FROM IMPULSES ALOFT INTERACTING WITH THE COASTAL FRONT.
SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... AS OF 3:30 PM
FRIDAY...COMPLEX FRONTAL SYSTEM OVER THE COASTAL CAROLINAS WILL
BRING SOUTH TO SOUTHWEST WINDS OF 15 TO 20 KTS AND 4 TO 6 FT SEAS
TO THE WATERS SATURDAY MORNING...WITH CONDITIONS GRADUALLY
IMPROVING THROUGH THE DAY. FRONTAL SYSTEM WILL PUSH OFFSHORE
OVERNIGHT...WITH WINDS TURNING OFFSHORE AFTER MIDNIGHT. RESULTING
LIMITED FETCH WILL ALLOW SEAS TO DROP BACK INTO THE 2 TO 4 FT
RANGE OVERNIGHT. RAINFALL ON SATURDAY MAY BE HEAVY AT
TIMES...RESTRICTING VISIBILITY SIGNIFICANTLY.
FAIRLY BENIGN3CONDITIONS WILL CONTINUE INTO SUNDAY WITH SEAS
MAINLY IN THE 2 TO 4 FT RANGE AND LIGHT WINDS DURING THE DAYTIME
HOURS. WINDS WILL VEER TO THE NE OVERNIGHT AS A WARM FRONT
APPROACHES FROM THE SOUTH...INCREASING TO 10 TO 15 KTS BY DAYBREAK
ON MONDAY.
LONG TERM /MONDAY THROUGH WEDNESDAY/...
AS OF 3:30 PM FRIDAY...GRADIENT WILL TIGHTEN THROUGH MONDAY AS HIGH
PRESSURE EXTENDING DOWN FROM THE GREAT LAKES SHIFTS EAST WHILE LOW
PRESSURE SYSTEM MAKES ITS WAY UP FROM THE GULF COAST. EXPECT N-NE
WINDS EARLY MONDAY SHIFTING AROUND AND INCREASING AS WARM
FRONT/COASTAL TROUGH PUSHES INLAND BY TUESDAY. SEAS AROUND 2 TO 3 FT
MON MORNING WILL INCREASE THROUGH THE DAY WITH INCREASING NE TO E
FLOW REACHING UP TO A SOLID 20 KTS THROUGH MON NIGHT. THIS WILL PUSH
SEAS UP ABOVE SCA THRESHOLDS BY MIDNIGHT AND REMAINING 6 TO 8 FT IN
OUTER WATERS AND 4 TO 6 FT NEAR SHORE THROUGH TUES MORNING.
AS THE LOW LIFTS OFF TO THE NORTH LATE TUESDAY THE WINDS WILL VEER
AROUND TO THE W-SW REMAINING THAT WAY THROUGH MID WEEK. THE
WEAKENING OFF SHORE FLOW WILL ALLOW SEAS TO SUBSIDE BELOW SCA
THRESHOLDS BY LATE TUES DROPPING FURTHER TO 2 TO 4 FT THROUGH
WEDNESDAY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 10 AM EST SATURDAY FOR AMZ254-256.
SMALL CRAFT ADVISORY UNTIL 6 PM EST SATURDAY FOR AMZ250-252.
&&
$$
SYNOPSIS...REK
NEAR TERM...DCH
SHORT TERM...REK
LONG TERM...RGZ
AVIATION...SGL
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
326 AM CST SAT FEB 23 2013
.SHORT TERM (TODAY-MONDAY NIGHT)...
INITIALLY CLOUDS AND FOG WILL BE THE CONCERN. OTHERWISE...CLOUDS
AND LIGHT SNOW CHANCES WILL BE THE CHALLENGE. 00Z MODELS IN
DECENT AGREEMENT ALTHOUGH WITH DETAIL DIFFERENCES SUNDAY INTO
MONDAY. WILL USE A BLEND FOR THIS FORECAST.
THE FORECAST AREA (FA) IS CURRENTLY STUCK WITHIN A VERY WEAK FLOW
ENVIRONMENT. LOW CLOUDS EXIST ALONG AND EAST OF THE VALLEY. THESE
CLOUDS SEEM TO BE OCCURRING WHERE MODELS SHOW 925MB WINDS CALM TO
5 KNOTS. WILL USE THE RAP AS GUIDANCE FOR WHEN SKIES WILL CLEAR
FROM WEST TO EAST (AS LOW LEVEL FLOW INCREASES). THIS SLOWS THE
CLEARING TREND TODAY. PATCHY DENSE FOG HAS OCCURRED WITHIN THIS
WEAK FLOW ENVIRONMENT...BUT 1/4SM VSBY HAS NOT BEEN CONSISTENT
FROM HOUR TO HOUR. WILL KEEP PATCHY FOG IN THE GRIDS THROUGH THE
MORNING HOURS WHERE CLOUDS (WEAK MIXING) IS EXPECTED...AND MONITOR
FOG CONDITIONS.
FOR SUNDAY INTO MONDAY...SOUTHERN STREAM ENERGY WILL REMAIN WELL
SOUTH OF THE REGION...BUT THERE WILL BE A WEAK NORTHERN STREAM
WAVE THAT AFFECTS THE REGION DURING THIS TIME. THE ECMWF IS
STRONGER WITH THE RIDGING TO THE EAST...AND KEEPS THIS FEATURE
WEST OF OTHER MODELS (WESTERN DAKOTAS VS EASTERN DAKOTAS) AS IT
DROPS TO THE SOUTH AND INTO THE SOUTHERN STREAM WAVE. THE MAIN
AFFECT OF THIS WAVE WILL LIKELY BE CLOUD COVER...BUT LIGHT SNOW
IS ALSO POSSIBLE. THE EXACT LOCATION OF THIS WAVE WILL DETERMINE
WHERE/WHEN THE LIGHT SNOW OCCURS. IF THE ECMWF IS CORRECT
ACCUMULATIONS WILL BE MAYBE A DUSTING...AND IF THE OTHER MODELS
ARE CORRECT ACCUMULATIONS COULD BE AN INCH OR TWO. WILL MAINTAIN
PREVIOUS FORECAST OF LOW POPS ACROSS THE WESTERN FA WITH ONLY A
DUSTING POSSIBLE (AS PMDHMD PREFERS THE ECMWF).
.LONG TERM (TUESDAY-FRIDAY)...
MODELS CONTINUE TO BE IN FAIR AGREEMENT WITH A QUIET WEATHER PATTERN
FOR THE CWFA FOR THE EXTENDED TIME FRAME WITH A SPLIT FLOW IN THE
STORM TRACK. 500MB FLOW WILL TRANSITION FROM AN ARKANSAS CUTOFF LOW
WITH THE NWERLY ORIENTED TROUGH THROUGH THE NORTHERN US ROCKIES INTO
A POSITIVE PNA PATTERN...WESTERN RIDGE AND EASTERN TROUGH ACROSS THE
CONUS...BY THE END OF THE PERIOD. WITH LITTLE UPPER LEVEL ENERGY
MOVING ACROSS THE AREA ONLY SLIGHT CHC FOR POPS WITH -SN POSSIBLE
TUE AND WED ACROSS THE SOUTH AND EAST ZONES WITH TEMPS NEAR END OF
FEB NORMALS.
&&
.AVIATION...
IFR/LIFR CIGS/VSBY ALONG AND EAST OF THE RED RIVER VALLEY ARE
EXPECTED TO SLOWLY IMPROVE FROM WEST TO EAST TODAY. THE MAIN
QUESTION IS WHEN THIS WILL OCCUR. THE THOUGHT IS THAT AS LONG AS
LOW LEVEL FLOW REMAINS WEAK THE LOW CIGS WILL REMAIN. WILL FOLLOW
MODEL 925MB WINDS ABOVE 5 KNOTS FOR INCREASED LOW LEVEL MIXING AND
CLEARING. THIS CLEARS THE VALLEY TAFS LATE MORNING...AND THE
EASTERN FA (KBJI) SOMETIME TOWARD SUNRISE ON SUNDAY.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
TG/JK
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1203 AM CST SAT FEB 23 2013
.UPDATE...FOR 06Z TAFS...
&&
.AVIATION...
AN AXIS OF LIGHT SHOWERS WILL REMAIN TO THE SOUTH AND EAST OF
MIDDLE TENNESSEE TONIGHT. A WEAK FRONT HAS MOVED JUST EAST OF
NASHVILLE INFLUENCING WINDS TO REMAIN OUT OF THE WNW FOR CKV AND
BNA FOR THE REMAINDER OF THE FORECAST PERIOD. THE BOUNDARY WILL
CONTINUE TO SLOWLY MOVE EAST DURING THE EARLY MORNING
HOURS...KEEPING CSV IN AN AREA OF LIGHT WINDS AND FOG...WHICH
COULD POSSIBLY REDUCE VISIBILITY TO A MILE AT TIMES. CIGS COULD
BRIEFLY LOWER TO IFR CONDITIONS AT BNA EARLY SATURDAY MORNING. CSV
CIGS ARE ALSO EXPECTED TO REMAIN WITHIN LIFR CONDITIONS FOR MOST
OF THE EARLY MORNING HOURS UNTIL THE BOUNDARY FINALLY MOVES
FARTHER EAST OF THE MID STATE LATER SATURDAY MORNING...WITH
CONDITIONS IMPROVING THROUGHOUT THE DAY ON SATURDAY.
&&
.PREV DISCUSSION... /ISSUED 807 PM CST FRI FEB 22 2013/
UPDATE...
LATEST REGIONAL RADAR IMAGERY SHOWS SCATTERED RAIN ACROSS NORTHERN
MISSISSIPPI AND ALABAMA INTO EAST TENNESSEE. ACTIVITY HAS BEEN
REMAINING TO THE SOUTHEAST OF THE CWA SO FAR...AND APPEARS THIS
TREND WILL CONTINUE THROUGH MUCH OF THE NIGHT WITH ONLY THE FAR
EASTERN AND SOUTHEASTERN ZONES LIKELY TO BE AFFECTED BY ANY
PRECIP. WITH SHORT TERM GUIDANCE INCLUDING THE HRRR AND 00Z NAM
AGREEING WITH THIS SCENARIO...WILL TRIM POPS BACK FURTHER TOWARDS
THE SOUTHEAST. WILL ALSO KEEP IN MENTION OF PATCHY FOG OVER THE
SOUTHEAST HALF OF THE CWA AS DEWPOINT DEPRESSIONS ARE ALREADY
LOW...AND WILL BE SEVERAL HOURS BEFORE APPROACHING COLD FRONT OVER
NORTHWEST ZONES REACHES THIS AREA. REST OF FORECAST APPEARS TO BE
ON TRACK.
PREV DISCUSSION... /ISSUED 641 PM CST FRI FEB 22 2013/
UPDATE...FOR 00Z TAFS...
AVIATION...
MAINLY VFR CONDITIONS THIS EVENING FOR CKV AND BNA. AFTER MIDNIGHT
CEILINGS ARE EXPECTED TO LOWER TO MVFR CONDITIONS...WITH IFR
CONDITIONS POSSIBLE IN NASHVILLE AS CIGS DROP BELOW 1000 FEET IN
THE EARLY MORNING HOURS. CONDITIONS AT CSV REMAIN WITHIN IFR
CONDITIONS WITH CONDITIONS DETERIORATING AS THE NIGHT PROGRESSES.
CEILINGS ARE FORECAST TO CONTINUE LOWERING THIS EVENING AS A BAND
OF MOISTURE MOVES JUST SOUTH AND EAST OF THE MID STATE. VIS AT CSV
MAY BE REDUCED TO 1 MILE OR LESS SATURDAY MORNING DUE TO FOG.
CONDITIONS SHOULD IMPROVE CLOSER TO NOON ON SATURDAY AS A FRONT
PASSES THROUGH THE AREA.
PREV DISCUSSION... /ISSUED 320 PM CST FRI FEB 22 2013/
DISCUSSION...
TEMPS DROP OFF CONSIDERABLY TO THE WEST OF NASHVILLE BEHIND THE COLD
FRONT. THIS BOUNDARY IS RUNNING PARALLEL TO THE UPPER FLOW BUT WILL
SLOWLY MOVE THROUGH AND WILL REACH EAST TN TONIGHT. THE BOUNDARY
WILL THEN SLOW DOWN AND STALL. SFC ENERGY WILL THEN LIFT NE ALONG
THE BOUNDARY AND SPREAD MOISTURE NORTHWARD. LOOKS AS THOUGH THE
MOISTURE WILL FOR THE MOST PART STAY SOUTH OF MIDDLE TN.
ALTHOUGH...SOME SHOWER ACTIVITY COULD REACH THE PLATEAU AND SRN
AREAS OVERNIGHT. WILL INCLUDE LOW POPS FOR EASTERN AND SOUTHERN
PORTIONS. OTHERWISE...DESPITE THE FROPA AND SOME LOWERING DEW
POINTS...DEW POINT DEPRESSIONS WILL BE RATHER LOW BY
12Z...PARTICULARLY ACROSS THE EASTERN HALF OF THE CWA. WILL ALSO
INCLUDE SOME PATCHY LATE NIGHT FOG.
ON SATURDAY...SFC HIGH WILL BUILD IN WITH SOME DRIER AIR WINNING
OUT. THIS TREND WILL CONTINUE INTO SUNDAY...AND WITH AMPLIFIED
HEIGHTS...SHOULD SEE TEMPS BACK UP INTO THE 50S FOR BOTH DAYS.
IN THE EXT FCST...MODELS ARE CONTINUING TO TREND TOWARD A COLDER AND
SOMEWHAT UNSETTLED PATTERN. UPPER LEVEL TROUGHING IS EXPECTED
WITH SEVERAL DISTURBANCES MOVING THROUGH THE AREA.
THE FIRST SYSTEM WILL BE ON MONDAY WITH A POTENT NEGATIVELY TILTED
UPPER LOW AXIS. THIS FEATURE WILL PASS NORTH OF TN AND WILL DRAG AN
ASSOCIATED FROPA THROUGH ON TUESDAY. RAIN PROBABILITIES LOOK HIGH
FOR MONDAY INTO TUESDAY. SYNOPTIC FEATURES SUPPORT THE POTENTIAL FOR
SOME WRAP AROUND SNOWFALL. HOWEVER...MODEL SFC TEMPS LOOK TOO WARM
AND EVEN A 5 DEGREE UNDERCUT WILL NOT SUPPORT SUFFICIENTLY LOW
ENOUGH FREEZING LEVEL SUPPORT. THUS...WILL LEAN TOWARD MOSTLY RAIN
FOR TUESDAY.
WED NT INTO THU...NEXT IMPULSE TO MOVE THROUGH. MODELS CONVERGE TO
SUPPORT TEMPS THAT WILL BE COLD ENOUGH TO SUPPORT AM
RAINFALL/SNOWFALL...RAIN IN AFTERNOON. SYSTEM DOES NOT CARRY AN
ABUNDANCE OF ORGANIZATION SO WILL KEEP POPS LOW. GFS THEN LEANS
TOWARD YET ANOTHER DISTURBANCE FOR FRIDAY. WILL OPT TO KEEP A
FLURRIES OR LIGHT SNOW SHOWERS GOING THU NT AD FRIDAY.
FOR THE EXT TEMPS...IT WILL BE DO OR DIE TIME VERSUS THE GUIDANCE.
MEX IS CARRYING HIGHS OF 45 TO 50 FOR BNA. THE MODELS ARE ALL
CONVERGING ON LOW HEIGHTS...CLOUDS AND SOME PRECIP...AD 850 MB TEMPS
OF UP TO -5 TO -10. WILL ROLL THE DICE AND UNDERCUT THE MEX NUMBERS
DECISIVELY. PERHAPS JUST A SLIGHT UNDERCUT ON OVERNIGHT LOWS.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
11
AREA FORECAST DISCUSSION
NWS SPOKANE WA
947 PM PST Fri Feb 22 2013
.SYNOPSIS...An upper level trough will move through the Pacific
Northwest tonight and exit the region early Saturday morning. Pacific
Northwest today and tonight. This will result in windy conditions
and moderate snow in the mountains. Mountain snow showers will
likely linger into Saturday afternoon. A short break in the
active weather is expected Saturday night and Sunday, before
the next in a series of frontal systems brings increasing chances
for rain and snow to the region on Monday. This active late winter
weather pattern will continue through the next week.
&&
.DISCUSSION...
Upon further investigation concerning a small localized vorticity
maximum quite evident rotating around on the satellite and radar
imagery as it moves slowly along eastward in close proximity to
the Southern British Columbia border and how the latest HRRR shows
it to remain intact as it does so through at least 12Z Instead of
ending the Winter storm warnings that were to expire in that
location I have extended them to 4AM and will reword them to
address this more intense but yet localized and complex convective
snowfall resulting from it as it passes...since snow levels should
continue to crash and allow for some accumulation to valley
floors. /Pelatti
&&
.AVIATION...
06Z TAFS: Jet stream associated with passing cold front and
cold and unstable airmass sagging down over the aviation area will
keep robust and gusty surface wind at many of the aviation sites
and possibly some low level wind shear as well as wind aloft is
quite strong. Snow levels lower and the probability of snow
showers decreases as if they occur they will be highly localized
so as not to cause too many drastic drops in ceilings and no
widespread impact on ceilings either. /Pelatti
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 29 40 25 36 29 39 / 10 20 10 20 30 70
Coeur d`Alene 30 38 26 36 30 38 / 10 30 10 20 30 70
Pullman 31 40 26 39 29 41 / 40 50 20 20 30 70
Lewiston 35 48 31 46 33 48 / 10 50 20 10 10 60
Colville 28 42 24 39 29 40 / 30 20 10 20 50 70
Sandpoint 29 38 25 35 30 36 / 70 50 10 30 40 70
Kellogg 29 37 26 34 28 37 / 50 80 20 30 30 60
Moses Lake 30 50 27 46 32 47 / 0 10 0 10 50 30
Wenatchee 30 47 28 43 31 43 / 10 10 0 10 40 30
Omak 23 40 19 35 25 38 / 0 10 0 10 50 60
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...Wind Advisory until 4 PM PST Saturday for Coeur d`Alene Area-
Idaho Palouse.
Winter Storm Warning until 7 PM PST Saturday for Central
Panhandle Mountains.
Winter Weather Advisory until 7 PM PST Saturday for Lewis and
Southern Nez Perce Counties.
Winter Storm Warning until 4 AM PST Saturday for Northern
Panhandle.
WA...Winter Weather Advisory until 10 AM PST Saturday for East Slopes
Northern Cascades.
Wind Advisory until 4 PM PST Saturday for Lower Garfield and
Asotin Counties-Spokane Area-Upper Columbia Basin-
Washington Palouse.
Winter Storm Warning until 4 AM PST Saturday for Northeast
Mountains.
Winter Storm Warning until 7 PM PST Saturday for Northeast Blue
Mountains.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
319 AM CST SAT FEB 23 2013
.SHORT TERM...TODAY THROUGH MONDAY NIGHT
319 AM CST SAT FEB 23 2013
FORECAST CHALLENGES GOING THROUGH EARLY NEXT WEEK REVOLVE AROUND
WHEN THE FLURRIES/SKIES CLEAR OUT TODAY/TONIGHT ALONG WITH WHEN THE
NEXT ROUND OF LIGHT SNOW MAY MOVE IN ON MONDAY.
CYCLONIC FLOW FROM THE SURFACE THROUGH THE UPPER ATMOSPHERE WILL
LINGER ACROSS THE REGION FOR MUCH OF TODAY BEFORE A SURFACE TO
UPPER LEVEL RIDGE AXIS PROPAGATES IN FROM THE WEST TONIGHT. WITH
THE CYCLONIC FLOW HANGING ON FOR MUCH OF TODAY...EXPECT THAT THE
CLOUD COVER AND FLURRIES/SNOW SHOWERS WILL CONTINUE AS WELL AND
THAT THE DRY AIR TO THE SOUTHWEST WILL STRUGGLE TO MOVE IN. BY 00Z
TONIGHT...THE 23.07Z RAP HAS THE SURFACE RIDGE ALIGNED ALONG THE
MISSISSIPPI RIVER...SO AT LEAST EXPECT THAT THE FLURRIES WILL HAVE
ENDED BY THEN ALONG AND WEST OF THE RIVER. HOWEVER...CLOUD COVER
MAY LINGER WITH THE UPPER RIDGE STILL IN THE DAKOTAS. HAVE PLAYED
CLOUD COVER A BIT ON THE PESSIMISTIC SIDE THROUGH TONIGHT AS A
RESULT.
BEYOND THIS THE PATTERN IS FAIRLY QUIET THROUGH THE REST OF THE
WEEKEND AS THE RIDGE SHIFTS TO THE EAST WITH TEMPERATURES AND
CLOUD COVER THE ONLY ISSUES TO CONTEND WITH. THERE IS NOT MUCH IN
THE WAY OF LOW LEVEL COLD AIR ADVECTION KICKING IN BEHIND THIS
SYSTEM...SO EXPECT THAT TEMPERATURES WILL REMAIN NEAR NORMAL
THROUGH MONDAY NIGHT.
THE FOCUS THEN GOES TO THE NEXT SYSTEM THAT COULD IMPACT THE AREA
WHICH IS A COMBINATION OF A NORTHERN STREAM WEAKENING MID LEVEL
SHORT WAVE TROUGH AND A SOUTHERN STREAM DEEPENING LOW. THE TREND
CONTINUES TO BE TO GO SLOWER WITH THE NORTHERN STREAM SHORT WAVE
AS A BLOCKING RIDGE ALONG THE ATLANTIC COAST STALLS OUT THE FLOW.
THE SURFACE REFLECTION FROM THIS SYSTEM IS A TROUGH THAT TRACKS
ACROSS THE DAKOTAS AND STALLS ACROSS MINNESOTA AS THE SOUTHERN
STREAM SYSTEM STARTS TO DEEPEN. THE 23.00Z GFS IS THE MOST ROBUST
WITH QPF EXTENDING NORTH ALONG THIS SURFACE TROUGH WHILE THE REST
OF THE GUIDANCE IS DRY. THEREFORE...HAVE BACKED OFF ON
PRECIPITATION CHANCES FOR MONDAY NIGHT AND KEPT THEM RELEGATED TO
PORTIONS OF SOUTH CENTRAL MINNESOTA INTO NORTHEAST IOWA.
.LONG TERM...TUESDAY THROUGH FRIDAY
319 AM CST SAT FEB 23 2013
THIS AFOREMENTIONED SOUTHERN STREAM SYSTEM APPEARS TO BE COMING
TOGETHER BY TUESDAY WITH THE 23.00Z GUIDANCE LOCKING IN ON A MORE
SOUTHERN TRACK WITH THIS SURFACE LOW. THE 23.00Z GFS/ECMWF/GEM ALL
ADVERTISE THIS LOW RUNNING FROM ST LOUIS OVER TO INDIANAPOLIS
TUESDAY WHICH SHOULD KEEP THE MAIN BAND OF SNOW OFF TO THE
SOUTHEAST. THE 23.00Z GFS IS FURTHEST TO THE NORTHWEST WHILE THE
GEM/ECMWF ARE NEARLY IDENTICAL WITH THEIR TRACK. HAVE BACKED OFF
ON SNOW CHANCES FOR TUESDAY ACROSS SOUTHWEST WISCONSIN AS A
RESULT. AFTER THIS SYSTEM MOVES THROUGH...ANOTHER MID LEVEL TROUGH
WILL DIG DOWN THROUGH THE NORTHWEST FLOW AND REINFORCE THE CUT OFF
CLOSED LOW ACROSS THE EASTERN US. THIS WILL KEEP CYCLONIC FLOW IN
PLACE ACROSS THE REGION THROUGH THURSDAY WITH SOME LIGHT SNOW
POSSIBLE. THE 23.00Z GEM IS THE DRIEST OF THE GUIDANCE AND FOCUSES
THIS TROUGH FURTHER TO THE SOUTH AND WOULD KEEP THE REGION ON THE
DRY SIDE. DESPITE THESE HIGHLY AMPLIFIED SYSTEMS MOVING THROUGH
THE UPPER MIDWEST...THE MAIN POOL OF COLD ARCTIC AIR IS CONFINED
TO FAR NORTHERN CANADA WITH 850MB TEMPERATURES IN THE 0C TO -10C
RANGE ACROSS THE SOUTHERN HALF OF CANADA. THUS...IT DOES NOT LOOK
LIKE TEMPERATURES WILL TAKE MUCH OF A DIP AROUND HERE AS THE
NORTHERLY FLOW SETS UP TOWARD MID WEEK.
&&
.AVIATION...THROUGH 06Z SUNDAY
1126 PM CST FRI FEB 22 2013
CEILING HEIGHTS ARE THE MAIN CONCERN WITH THIS SET OF TAFS. BUFKIT
SOUNDINGS CONTINUE TO SHOW LOW LEVEL MOISTURE IN PLACE...BUT MAYBE
A LITTLE OVERDONE BASED ON THE 00Z MPX SOUNDING. VERY LITTLE IN
THE WAY OF MVFR CEILINGS NOW BEING SEE ACROSS MINNESOTA.
HOWEVER...DO FEEL THAT CEILINGS WILL LOWER LATER TONIGHT BUT NOT
AS LOW AS PREVIOUSLY THOUGHT. DOD DID LOWER INTO THE 020K-030K
FEET RANGE. WITH THE CYCLONIC FLOW CONTINUING SATURDAY...EXPECT
THE MVFR CEILINGS TO RAISE BACK INTO THE VFR CATEGORY AND THEN
PERSIST THROUGH 06Z. COULD BE SOME BREAKS IN THE CLOUDS LATE IN THE
AFTERNOON AND EVENING...BUT DID KEEP A BROKEN DECK IN THROUGH 06Z.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
319 AM CST SAT FEB 23 2013
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
519 AM CST SAT FEB 23 2013
.AVIATION...
MVFR CONDITIONS WILL SLOWLY IMPROVE TO VFR THROUGH 21Z/23 WITH
VCNTY SHSN POSSIBLE AT KDBQ AND MAYBE AT KCID/KMLI. AFT 00Z/24
HIGH PRESSURE WILL BUILD INTO THE WESTERN GREAT LAKES. VFR
CONDITIONS ARE EXPECTED TO CONTINUE. HOWEVER...LIGHT WINDS AND
MAINLY CLEAR SKIES MAY RESULT IN FG DVLPMNT PRIOR TO SUNRISE
SUNDAY. ..08..
&&
.PREV DISCUSSION... /ISSUED 304 AM CST SAT FEB 23 2013/
SYNOPSIS...
06Z SFC ANALYSIS HAS AN OCCLUDED LOW NEARING THE MACKINAC STRAITS
WHILE HIGH PRESSURE WAS ACROSS THE PLAINS. DEW POINTS WERE IN THE
SINGLE DIGITS AND TEENS ACROSS THE PLAINS WITH 20S AND 30S ACROSS
THE GREAT LAKES AND OHIO VALLEY.
SHORT TERM...TODAY AND TONIGHT...
A COMBINATION OF CYCLONIC FLOW ALOFT AND VORT MAXES...MAINLY AT 700
MB IS PRODUCING FLURRIES/LIGHT SNOW ACROSS THE NORTHERN PART OF THE
CWFA AND UP INTO MINNESOTA. THE RAP TRENDS HAVE THE 700MB SHORTWAVE
ROTATING THROUGH DURING THE DAY WITH NEAR CONTINUOUS 700MB VORT
MAXES ROTATING THROUGH. THUS FLURRIES/VERY LIGHT SNOW WILL BE SEEN
ACROSS ROUGHLY THE NORTHERN HALF DURING THE MORNING.
FCST SOUNDINGS SHOW A DRYING ALOFT OCCURRING DURING THE AFTERNOON SO
ANY FLURRIES/LIGHT SNOW WILL GRADUALLY END.
BASED ON 0.5KM CONDENSATION PRESSURES/WIND...CLOUDS SHOULD STAY PUT
FOR MUCH OF THE MORNING BEFORE CLEARING STARTS FROM WEST TO EAST
DURING THE AFTERNOON. THE COLD POOL ALOFT MAY HELP GENERATE SOME
DIURNAL CLOUDS WHICH MAY SLOW THE RATE OF CLEARING DURING THE
AFTERNOON HOURS. ..08..
LONG TERM...SUNDAY THROUGH NEXT FRIDAY...
THE EXTENDED STORM IS IN MUCH BETTER AGREEMENT IN MODEL FORECASTS
TONIGHT...AND IS FOCUSED ON A SURFACE LOW TRACK FROM OK/AR THROUGH
INDIANA MONDAY INTO TUESDAY. THE STORM SHOULD ONCE AGAIN HAVE A
BROAD UPPER LOW ASSOCIATED WITH IT...AND BY IN LARGE...THE UPPER LOW
SHOULD DOMINATE THE AREAL PLACEMENT OF RAIN AND SNOW. THE BIGGEST
DIFFERENCE IN MODELS TONIGHT...IS THAT NO MODEL FORECASTS AN
INTENSIFYING SURFACE LOW...OR EVEN A STRONG OCCLUDED LOW AS IT MOVES
PAST THE REGION. THIS WOULD INDICATE A MUCH LOWER RISK FOR A STRONG
WIND DRIVEN SNOW/BLIZZARD THAN THE EARLIER 12Z ECMWF WOULD HAVE
INDICATED. DESPITE THIS...THE STORM SHOULD BE ABLE TO PRODUCE A
HEALTHY DEFORMATION ZONE...AND ALL MODELS BRUSH THIS FORCING THROUGH
THE CENTRAL AND SOUTHERN CWA...AND THIS MAY REQUIRE HEADLINES TO BE
ISSUED TODAY IN OUR SOUTH. MODERATE SNOW ACCUMULATIONS OVER 3 INCHES
SEEM LIKELY WITH THIS SYSTEM...AND SHOULD A DIRECT HIT FROM THE DEF
ZONE OCCUR...HEAVY AMOUNTS ARE POSSIBLE. AS THE SYSTEM MOVES PAST
INTO THE LOWER GREAT LAKES...MORE ENERGY IS FORECAST BY THE GFS AND
ECMWF TO MOVE INTO THE WESTERN SIDE OF THE UPPER LOW...AND THIS
SHOULD PRODUCE AN EXTENDED PERIOD OF LIGHT SNOW BEGINNING TUESDAY
NIGHT INTO WEDNESDAY NIGHT. THE GFS IS MOST BULLISH...WITH 1 TO 2
INCHES OF SNOW FOR SEVERAL PERIODS IN A ROW FOR A LARGE AREA...WHILE
THE ECMWF IS MORE CONSERVATIVE. ANY WAY YOU SHAKE IT...IT APPEARS
UNSETTLED...CLOUDY...WITH LIGHT SNOW OR FLURRIES IN THE WAKE OF THE
EARLY WEEK STORM...AT LEAST THROUGH WEDNESDAY NIGHT.
LATE WEEK...MODELS SHOW A MUDDLED MESS OF NORTHERLY FLOW ALOFT.
THERE CERTAINLY COULD BE SOME SNOW POTENTIAL THERE...BUT IF IT WOULD
OCCUR...MOISTURE WOULD BE VERY LIMITED...AND AMOUNTS VERY LIGHT.
TEMPERATURES WILL AGAIN BE FORECAST TO AVERAGE BELOW NORMAL ON
HIGHS...MAINLY IN THE LOWER TO MID 30S THIS WEEK. LOWS IN THE TEENS
TO MID 20S ARE FORECAST FROM NORTHWEST TO SOUTHEAST...WITH THE
MILDEST LOWS ASSOCIATED WITH MONDAY NIGHT AND TUESDAY NIGHT AS WE
SHOULD EXPERIENCE HIGHER DEWPOINTS WITH THE POTENTIAL SNOW EVENT.
ERVIN
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION...CORRECTED
NWS BILLINGS MT
540 AM MST SAT FEB 23 2013
.SHORT TERM...VALID FOR TDY AND SUN...
WE UPDATED THE FORECAST TO CANCEL THE WIND ADVISORY FOR LIVINGSTON
AND NYE SINCE OBSERVATIONS HAVE WINDS WELL BELOW CRITERIA NOW. THE
SURFACE PRESSURES ARE FALLING ACROSS YELLOWSTONE PARK AS THE LEFT
EXIT REGION OF THE 300-HPA JET STREAK APPROACHES...SO THE GRADIENT
IS NO LONGER TIGHT ENOUGH TO SUPPORT STRONG GAP WINDS. SCHULTZ
PREVIOUS DISCUSSION...ISSUED AT 308 AM MST SAT FEB 23 2013...
PASSAGE OF A 500-HPA SHORT WAVE TROUGH AND SURFACE COLD FRONT WILL
BRING SNOW SHOWER CHANCES TO THE FOREFRONT TODAY. MOISTURE CHANNEL
IMAGERY AT 10 UTC SHOWS THAT TROUGH AXIS ENTERING WESTERN ID...AND
THAT IS STARTING TO DISRUPT THE ENVIRONMENT NEEDED FOR NOTABLE GAP
WINDS. THAT PROCESS SHOULD BE COMPLETE BETWEEN 12 AND 15 UTC...BUT
IN THE INTERIM WE WILL LET OUR WIND ADVISORY AT LIVINGSTON AND NYE
RIDE FOR A FEW MORE HOURS.
TODAY AND TONIGHT...WE HAVE POPS IN THE 60 TO 90 PERCENT RANGE FOR
1/ THE LIVINGSTON...BIG TIMBER...AND COOKE CITY AREAS UNTIL 18 UTC
AND 2/ THE LODGE GRASS...SHERIDAN...AND EVEN BROADUS AREAS BETWEEN
18 AND 06 UTC. THOSE LIKELY AND CATEGORICAL POPS ARE LINED UP WITH
THE MOST GENEROUS SYNOPTIC-SCALE FORCING WITH THE SHORT WAVE ALOFT
AND THE EXIT REGION OF A WEAKENING 300-HPA JET STREAK WHICH THE 00
UTC GUIDANCE SHOWS SINKING SOUTHWARD TODAY. WE HAVE CHANCE POPS IN
MOST OTHER PLACES DURING THE DAY...INCLUDING BILLINGS...BUT DIDN/T
GO ANY HIGHER IN ORDER TO CONVEY THE MORE SCATTERED OR SHORT-LIVED
NATURE OF SHOWERS OUTSIDE OF THE BETTER FORCING. SNOW IS MENTIONED
AS THE PREDOMINATE PRECIPITATION TYPE FOR MOST OF THE AREA BECAUSE
THAT NOTION HAS STRONG SUPPORT FROM GFS/ECMWF/NAM WET BULB HEIGHTS
AND NCEP PRECIPITATION-TYPE ALGORITHMS APPLIED TO THE 21 UTC SREF.
WHERE IMPACTS ARE CONCERNED...OUR MAIN CONCERN IS FOR SHERIDAN AND
MAYBE EVEN SOUTHERN BIG HORN COUNTY...WHERE THERE IS SOME RISK OF
ADVISORY-LEVEL SNOWFALL THIS AFTERNOON AND EVENING. THE 00 UTC GFS
AND RECENT RUNS OF THE RAP /WHICH GETS LATERAL BOUNDARY CONDITIONS
FROM THE GFS/ ARE THE MOST AGGRESSIVE QPF SOLUTIONS FOR THAT AREA.
HOWEVER...SINCE THOSE QPF NUMBERS ARE HIGHER THAN MOST OF THE REST
OF THE PACK...AND BECAUSE IT IS NOT CLEAR HOW EFFICIENT UPSLOPE IN
THE LOW LEVELS WILL BE...WE CHOSE TO KEEP SNOW AMOUNTS IN THE 1 TO
3 INCH RANGE /JUST BELOW ADVISORY CRITERIA/ FOR NOW. THIS COULD BE
A CASE WHERE NEAR TERM OBSERVATIONAL TRENDS GIVE ENOUGH CONFIDENCE
FOR US TO HOIST A HEADLINE LATER TODAY IF GFS-BASED SOLUTIONS WIND
UP BEING CORRECT. THE 06 UTC GFS HAS TRENDED EVEN HIGHER WITH ITS
QPF...SO THIS SITUATION BEARS CLOSE WATCHING.
SUN...NORTH-NORTHWEST FLOW WILL BE IN PLACE ALOFT WITH BOTH MODEST
DRYING AND WARMING IN THE LOW- AND MID-LEVELS. WE DECIDED TO LEAVE
OUR GOING FORECAST ALONE FOR NOW SINCE IT SHOWS POPS MAINLY BEFORE
18 UTC...WHEN FLOW IS MORE CYCLONIC. HOWEVER...BOTH THE 00 UTC GFS
AND NAM SHOW A DECENT BATCH OF 500-300 HPA Q-VECTOR CONVERGENCE IN
THE 18 TO 00 UTC TIME FRAME...WHICH MAKES US WONDER IF THERE COULD
BE SOME CONVECTION DURING THE AFTERNOON. THAT WILL BE SOMETHING TO
CONSIDER WITH LATER FORECAST RELEASES. OTHERWISE...WE DID INCREASE
HIGHS USING THE 00 UTC BIAS-CORRECTED MULTI-MODEL CONSENSUS /WHICH
HAS VERIFIED WELL LATELY/...AND WINDS ON SUN NIGHT NEAR LIVINGSTON
AND BIG TIMBER AS SURFACE PRESSURE FALLS BEGIN ACROSS THE NORTHERN
ROCKIES AGAIN. SCHULTZ
.LONG TERM...VALID FOR MON...TUE...WED...THU...FRI...
MODELS IN PRETTY GOOD AGREEMENT THROUGH WEDNESDAY. SMALL SYSTEM
FOR THURSDAY SHOWS SOME SIGNS OF GETTING BETTER ORGANIZED IN THE
GFS BUT NOT SO MUCH IN THE EUROPEAN MODEL. STRONG RIDGING AND MUCH
WARMER TEMPERATURES LOOK TO BE ON TRACK FOR NEXT WEEKEND.
BRIEF RIDGING BEHIND SUNDAY SYSTEM SHOULD BRING PARTLY CLOUDY AND
DRY CONDITIONS TO THE FIRST HALF OF MONDAY. BY LATE IN THE DAY
NEXT SYSTEM UPSTREAM QUICKLY BUILDS INTO THE AREA WITH INCREASING
PRECIPITATION CHANCES THROUGH TUESDAY. SOME WEAK ENERGY LINGERS
INTO WEDNESDAY OVER SOUTHERN ZONES BUT BY WEDNESDAY AFTERNOON
RIDGING DEVELOPS ENDING PRECIPITATION CHANCES.
GFS BRINGS NEXT SYSTEM INTO IDAHO WEDNESDAY NIGHT AND SEEMS TO BE
TRYING TO CUT OFF UPPER LOW NEAR WEST YELLOWSTONE THURSDAY
MORNING. ECMWF DIGS THIS SAME TROF MUCH FURTHER SOUTH AND SPLITS
THE SYSTEM OVER THE AREA RESULTING IN SOME CLOUD COVER BUT LITTLE
IN THE WAY OF PRECIPITATION OUTSIDE OF MOUNTAIN AREAS. CAUSE OF
THE DIFFERENCES IS DUE TO HANDLING OF STRONG DOWNSTREAM SYSTEM
OVER THE EASTERN US...AND CURRENT GUIDANCE FAVORS THE EC SOLUTION
SO LEFT FORECAST DRY AND WARMED TEMPERATURES JUST A BIT.
ALL THE MODELS IN GOOD AGREEMENT WITH DEVELOPMENT OF STRONG
RIDGING FRIDAY THROUGH NEXT WEEKEND. BOTH MODELS SHOW SATURDAY 850
TEMPERATURES IN THE +6 TO +10C RANGE LEADING TO MIX DOWN
TEMPERATURES WELL INTO THE 50S FOR HIGHS FRIDAY THROUGH SUNDAY.
NOT OUT OF THE QUESTION TO SEE SOME LOWER 60S SATURDAY AND SUNDAY
WITH DRY CONDITIONS UNDER THE RIDGE. CHAMBERS
&&
.AVIATION...
GUSTY SOUTHWEST WINDS IN THE KLVM VICINITY WILL DECREASE THIS
MORNING BEHIND COLD FRONT. SCATTERED SNOW SHOWERS WILL DEVELOP
FROM WEST TO EAST ACROSS THE AREA TODAY AS THE COLD FRONT MOVES
THROUGH. VFR CONDITIONS WILL PREVAIL IN MOST AREAS WITH LOCAL
MVFR CONDITIONS NEAR SNOW SHOWERS. FOOTHILLS AND MOUNTAIN AREAS
WILL SEE MAINLY MVFR CONDITIONS WITH LOCAL IFR OR LOWER CONDITIONS
WITH HEAVIER SNOW SHOWERS EXPECTED IN THESE AREAS. MOUNTAIN AND
PASS OBSCURATION WILL EXIST FOR ALL AREA MOUNTAINS THROUGH
TONIGHT. CHAMBERS
&&
.PRELIMINARY POINT TEMP/POPS...
TDY SUN MON TUE WED THU FRI
-------------------------------------------------------
BIL 041 025/041 022/039 024/037 021/037 023/045 026/051
4/J 32/J 11/B 33/J 11/U 32/J 00/B
LVM 039 020/035 016/035 019/032 013/033 017/038 025/044
7/J 33/W 12/J 44/J 11/U 32/J 11/B
HDN 042 023/043 019/037 022/036 017/035 020/043 023/049
5/W 43/J 11/B 34/J 21/U 33/J 10/B
MLS 044 027/042 021/037 022/036 020/035 020/041 024/047
2/W 22/J 11/U 23/J 21/B 12/J 10/B
4BQ 041 024/038 017/035 020/033 018/032 017/039 020/045
6/W 73/J 11/U 24/J 21/B 12/J 10/B
BHK 041 024/035 016/032 019/031 018/031 016/036 018/040
3/J 22/J 11/U 13/J 21/B 11/B 10/B
SHR 038 020/036 012/034 018/032 015/033 016/039 018/045
7/J 83/J 11/U 44/J 21/U 22/J 10/B
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS BILLINGS MT
524 AM MST SAT FEB 23 2013
.SHORT TERM...VALID FOR TDY AND SUN...
WE UPDATED THE FORECAST TO CANCEL THE WIND ADVISORY FOR LIVINGSTON
AND NYE SINCE OBSERVATIONS HAVE WINDS WELL BELOW CRITERIA NOW. THE
SURFACE PRESSURES ARE FALLING ACROSS YELLOWSTONE PARK AS THE RIGHT
EXIT REGION OF THE 300-HPA JET STREAK APPROACHES...SO THE GRADIENT
IS NO LONGER TIGHT ENOUGH TO SUPPORT STRONG GAP WINDS. SCHULTZ
PREVIOUS DISCUSSION...ISSUED AT 308 AM MST SAT FEB 23 2013...
PASSAGE OF A 500-HPA SHORT WAVE TROUGH AND SURFACE COLD FRONT WILL
BRING SNOW SHOWER CHANCES TO THE FOREFRONT TODAY. MOISTURE CHANNEL
IMAGERY AT 10 UTC SHOWS THAT TROUGH AXIS ENTERING WESTERN ID...AND
THAT IS STARTING TO DISRUPT THE ENVIRONMENT NEEDED FOR NOTABLE GAP
WINDS. THAT PROCESS SHOULD BE COMPLETE BETWEEN 12 AND 15 UTC...BUT
IN THE INTERIM WE WILL LET OUR WIND ADVISORY AT LIVINGSTON AND NYE
RIDE FOR A FEW MORE HOURS.
TODAY AND TONIGHT...WE HAVE POPS IN THE 60 TO 90 PERCENT RANGE FOR
1/ THE LIVINGSTON...BIG TIMBER...AND COOKE CITY AREAS UNTIL 18 UTC
AND 2/ THE LODGE GRASS...SHERIDAN...AND EVEN BROADUS AREAS BETWEEN
18 AND 06 UTC. THOSE LIKELY AND CATEGORICAL POPS ARE LINED UP WITH
THE MOST GENEROUS SYNOPTIC-SCALE FORCING WITH THE SHORT WAVE ALOFT
AND THE EXIT REGION OF A WEAKENING 300-HPA JET STREAK WHICH THE 00
UTC GUIDANCE SHOWS SINKING SOUTHWARD TODAY. WE HAVE CHANCE POPS IN
MOST OTHER PLACES DURING THE DAY...INCLUDING BILLINGS...BUT DIDN/T
GO ANY HIGHER IN ORDER TO CONVEY THE MORE SCATTERED OR SHORT-LIVED
NATURE OF SHOWERS OUTSIDE OF THE BETTER FORCING. SNOW IS MENTIONED
AS THE PREDOMINATE PRECIPITATION TYPE FOR MOST OF THE AREA BECAUSE
THAT NOTION HAS STRONG SUPPORT FROM GFS/ECMWF/NAM WET BULB HEIGHTS
AND NCEP PRECIPITATION-TYPE ALGORITHMS APPLIED TO THE 21 UTC SREF.
WHERE IMPACTS ARE CONCERNED...OUR MAIN CONCERN IS FOR SHERIDAN AND
MAYBE EVEN SOUTHERN BIG HORN COUNTY...WHERE THERE IS SOME RISK OF
ADVISORY-LEVEL SNOWFALL THIS AFTERNOON AND EVENING. THE 00 UTC GFS
AND RECENT RUNS OF THE RAP /WHICH GETS LATERAL BOUNDARY CONDITIONS
FROM THE GFS/ ARE THE MOST AGGRESSIVE QPF SOLUTIONS FOR THAT AREA.
HOWEVER...SINCE THOSE QPF NUMBERS ARE HIGHER THAN MOST OF THE REST
OF THE PACK...AND BECAUSE IT IS NOT CLEAR HOW EFFICIENT UPSLOPE IN
THE LOW LEVELS WILL BE...WE CHOSE TO KEEP SNOW AMOUNTS IN THE 1 TO
3 INCH RANGE /JUST BELOW ADVISORY CRITERIA/ FOR NOW. THIS COULD BE
A CASE WHERE NEAR TERM OBSERVATIONAL TRENDS GIVE ENOUGH CONFIDENCE
FOR US TO HOIST A HEADLINE LATER TODAY IF GFS-BASED SOLUTIONS WIND
UP BEING CORRECT. THE 06 UTC GFS HAS TRENDED EVEN HIGHER WITH ITS
QPF...SO THIS SITUATION BEARS CLOSE WATCHING.
SUN...NORTH-NORTHWEST FLOW WILL BE IN PLACE ALOFT WITH BOTH MODEST
DRYING AND WARMING IN THE LOW- AND MID-LEVELS. WE DECIDED TO LEAVE
OUR GOING FORECAST ALONE FOR NOW SINCE IT SHOWS POPS MAINLY BEFORE
18 UTC...WHEN FLOW IS MORE CYCLONIC. HOWEVER...BOTH THE 00 UTC GFS
AND NAM SHOW A DECENT BATCH OF 500-300 HPA Q-VECTOR CONVERGENCE IN
THE 18 TO 00 UTC TIME FRAME...WHICH MAKES US WONDER IF THERE COULD
BE SOME CONVECTION DURING THE AFTERNOON. THAT WILL BE SOMETHING TO
CONSIDER WITH LATER FORECAST RELEASES. OTHERWISE...WE DID INCREASE
HIGHS USING THE 00 UTC BIAS-CORRECTED MULTI-MODEL CONSENSUS /WHICH
HAS VERIFIED WELL LATELY/...AND WINDS ON SUN NIGHT NEAR LIVINGSTON
AND BIG TIMBER AS SURFACE PRESSURE FALLS BEGIN ACROSS THE NORTHERN
ROCKIES AGAIN. SCHULTZ
.LONG TERM...VALID FOR MON...TUE...WED...THU...FRI...
MODELS IN PRETTY GOOD AGREEMENT THROUGH WEDNESDAY. SMALL SYSTEM
FOR THURSDAY SHOWS SOME SIGNS OF GETTING BETTER ORGANIZED IN THE
GFS BUT NOT SO MUCH IN THE EUROPEAN MODEL. STRONG RIDGING AND MUCH
WARMER TEMPERATURES LOOK TO BE ON TRACK FOR NEXT WEEKEND.
BRIEF RIDGING BEHIND SUNDAY SYSTEM SHOULD BRING PARTLY CLOUDY AND
DRY CONDITIONS TO THE FIRST HALF OF MONDAY. BY LATE IN THE DAY
NEXT SYSTEM UPSTREAM QUICKLY BUILDS INTO THE AREA WITH INCREASING
PRECIPITATION CHANCES THROUGH TUESDAY. SOME WEAK ENERGY LINGERS
INTO WEDNESDAY OVER SOUTHERN ZONES BUT BY WEDNESDAY AFTERNOON
RIDGING DEVELOPS ENDING PRECIPITATION CHANCES.
GFS BRINGS NEXT SYSTEM INTO IDAHO WEDNESDAY NIGHT AND SEEMS TO BE
TRYING TO CUT OFF UPPER LOW NEAR WEST YELLOWSTONE THURSDAY
MORNING. ECMWF DIGS THIS SAME TROF MUCH FURTHER SOUTH AND SPLITS
THE SYSTEM OVER THE AREA RESULTING IN SOME CLOUD COVER BUT LITTLE
IN THE WAY OF PRECIPITATION OUTSIDE OF MOUNTAIN AREAS. CAUSE OF
THE DIFFERENCES IS DUE TO HANDLING OF STRONG DOWNSTREAM SYSTEM
OVER THE EASTERN US...AND CURRENT GUIDANCE FAVORS THE EC SOLUTION
SO LEFT FORECAST DRY AND WARMED TEMPERATURES JUST A BIT.
ALL THE MODELS IN GOOD AGREEMENT WITH DEVELOPMENT OF STRONG
RIDGING FRIDAY THROUGH NEXT WEEKEND. BOTH MODELS SHOW SATURDAY 850
TEMPERATURES IN THE +6 TO +10C RANGE LEADING TO MIX DOWN
TEMPERATURES WELL INTO THE 50S FOR HIGHS FRIDAY THROUGH SUNDAY.
NOT OUT OF THE QUESTION TO SEE SOME LOWER 60S SATURDAY AND SUNDAY
WITH DRY CONDITIONS UNDER THE RIDGE. CHAMBERS
&&
.AVIATION...
GUSTY SOUTHWEST WINDS IN THE KLVM VICINITY WILL DECREASE THIS
MORNING BEHIND COLD FRONT. SCATTERED SNOW SHOWERS WILL DEVELOP
FROM WEST TO EAST ACROSS THE AREA TODAY AS THE COLD FRONT MOVES
THROUGH. VFR CONDITIONS WILL PREVAIL IN MOST AREAS WITH LOCAL
MVFR CONDITIONS NEAR SNOW SHOWERS. FOOTHILLS AND MOUNTAIN AREAS
WILL SEE MAINLY MVFR CONDITIONS WITH LOCAL IFR OR LOWER CONDITIONS
WITH HEAVIER SNOW SHOWERS EXPECTED IN THESE AREAS. MOUNTAIN AND
PASS OBSCURATION WILL EXIST FOR ALL AREA MOUNTAINS THROUGH
TONIGHT. CHAMBERS
&&
.PRELIMINARY POINT TEMP/POPS...
TDY SUN MON TUE WED THU FRI
-------------------------------------------------------
BIL 041 025/041 022/039 024/037 021/037 023/045 026/051
4/J 32/J 11/B 33/J 11/U 32/J 00/B
LVM 039 020/035 016/035 019/032 013/033 017/038 025/044
7/J 33/W 12/J 44/J 11/U 32/J 11/B
HDN 042 023/043 019/037 022/036 017/035 020/043 023/049
5/W 43/J 11/B 34/J 21/U 33/J 10/B
MLS 044 027/042 021/037 022/036 020/035 020/041 024/047
2/W 22/J 11/U 23/J 21/B 12/J 10/B
4BQ 041 024/038 017/035 020/033 018/032 017/039 020/045
6/W 73/J 11/U 24/J 21/B 12/J 10/B
BHK 041 024/035 016/032 019/031 018/031 016/036 018/040
3/J 22/J 11/U 13/J 21/B 11/B 10/B
SHR 038 020/036 012/034 018/032 015/033 016/039 018/045
7/J 83/J 11/U 44/J 21/U 22/J 10/B
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS BILLINGS MT
308 AM MST SAT FEB 23 2013
.SHORT TERM...VALID FOR TDY AND SUN...
PASSAGE OF A 500-HPA SHORT WAVE TROUGH AND SURFACE COLD FRONT WILL
BRING SNOW SHOWER CHANCES TO THE FOREFRONT TODAY. MOISTURE CHANNEL
IMAGERY AT 10 UTC SHOWS THAT TROUGH AXIS ENTERING WESTERN ID...AND
THAT IS STARTING TO DISRUPT THE ENVIRONMENT NEEDED FOR NOTABLE GAP
WINDS. THAT PROCESS SHOULD BE COMPLETE BETWEEN 12 AND 15 UTC...BUT
IN THE INTERIM WE WILL LET OUR WIND ADVISORY AT LIVINGSTON AND NYE
RIDE FOR A FEW MORE HOURS.
TODAY AND TONIGHT...WE HAVE POPS IN THE 60 TO 90 PERCENT RANGE FOR
1/ THE LIVINGSTON...BIG TIMBER...AND COOKE CITY AREAS UNTIL 18 UTC
AND 2/ THE LODGE GRASS...SHERIDAN...AND EVEN BROADUS AREAS BETWEEN
18 AND 06 UTC. THOSE LIKELY AND CATEGORICAL POPS ARE LINED UP WITH
THE MOST GENEROUS SYNOPTIC-SCALE FORCING WITH THE SHORT WAVE ALOFT
AND THE EXIT REGION OF A WEAKENING 300-HPA JET STREAK WHICH THE 00
UTC GUIDANCE SHOWS SINKING SOUTHWARD TODAY. WE HAVE CHANCE POPS IN
MOST OTHER PLACES DURING THE DAY...INCLUDING BILLINGS...BUT DIDN/T
GO ANY HIGHER IN ORDER TO CONVEY THE MORE SCATTERED OR SHORT-LIVED
NATURE OF SHOWERS OUTSIDE OF THE BETTER FORCING. SNOW IS MENTIONED
AS THE PREDOMINATE PRECIPITATION TYPE FOR MOST OF THE AREA BECAUSE
THAT NOTION HAS STRONG SUPPORT FROM GFS/ECMWF/NAM WET BULB HEIGHTS
AND NCEP PRECIPITATION-TYPE ALGORITHMS APPLIED TO THE 21 UTC SREF.
WHERE IMPACTS ARE CONCERNED...OUR MAIN CONCERN IS FOR SHERIDAN AND
MAYBE EVEN SOUTHERN BIG HORN COUNTY...WHERE THERE IS SOME RISK OF
ADVISORY-LEVEL SNOWFALL THIS AFTERNOON AND EVENING. THE 00 UTC GFS
AND RECENT RUNS OF THE RAP /WHICH GETS LATERAL BOUNDARY CONDITIONS
FROM THE GFS/ ARE THE MOST AGGRESSIVE QPF SOLUTIONS FOR THAT AREA.
HOWEVER...SINCE THOSE QPF NUMBERS ARE HIGHER THAN MOST OF THE REST
OF THE PACK...AND BECAUSE IT IS NOT CLEAR HOW EFFICIENT UPSLOPE IN
THE LOW LEVELS WILL BE...WE CHOSE TO KEEP SNOW AMOUNTS IN THE 1 TO
3 INCH RANGE /JUST BELOW ADVISORY CRITERIA/ FOR NOW. THIS COULD BE
A CASE WHERE NEAR TERM OBSERVATIONAL TRENDS GIVE ENOUGH CONFIDENCE
FOR US TO HOIST A HEADLINE LATER TODAY IF GFS-BASED SOLUTIONS WIND
UP BEING CORRECT. THE 06 UTC GFS HAS TRENDED EVEN HIGHER WITH ITS
QPF...SO THIS SITUATION BEARS CLOSE WATCHING.
SUN...NORTH-NORTHWEST FLOW WILL BE IN PLACE ALOFT WITH BOTH MODEST
DRYING AND WARMING IN THE LOW- AND MID-LEVELS. WE DECIDED TO LEAVE
OUR GOING FORECAST ALONE FOR NOW SINCE IT SHOWS POPS MAINLY BEFORE
18 UTC...WHEN FLOW IS MORE CYCLONIC. HOWEVER...BOTH THE 00 UTC GFS
AND NAM SHOW A DECENT BATCH OF 500-300 HPA Q-VECTOR CONVERGENCE IN
THE 18 TO 00 UTC TIME FRAME...WHICH MAKES US WONDER IF THERE COULD
BE SOME CONVECTION DURING THE AFTERNOON. THAT WILL BE SOMETHING TO
CONSIDER WITH LATER FORECAST RELEASES. OTHERWISE...WE DID INCREASE
HIGHS USING THE 00 UTC BIAS-CORRECTED MULTI-MODEL CONSENSUS /WHICH
HAS VERIFIED WELL LATELY/...AND WINDS ON SUN NIGHT NEAR LIVINGSTON
AND BIG TIMER AS SURFACE PRESSURE FALLS BEGIN ACROSS THE NORTHERN
ROCKIES AGAIN. SCHULTZ
.LONG TERM...VALID FOR MON...TUE...WED...THU...FRI...
MODELS IN PRETTY GOOD AGREEMENT THROUGH WEDNESDAY. SMALL SYSTEM
FOR THURSDAY SHOWS SOME SIGNS OF GETTING BETTER ORGANIZED IN THE
GFS BUT NOT SO MUCH IN THE EUROPEAN MODEL. STRONG RIDGING AND MUCH
WARMER TEMPERATURES LOOK TO BE ON TRACK FOR NEXT WEEKEND.
BRIEF RIDGING BEHIND SUNDAY SYSTEM SHOULD BRING PARTLY CLOUDY AND
DRY CONDITIONS TO THE FIRST HALF OF MONDAY. BY LATE IN THE DAY
NEXT SYSTEM UPSTREAM QUICKLY BUILDS INTO THE AREA WITH INCREASING
PRECIPITATION CHANCES THROUGH TUESDAY. SOME WEAK ENERGY LINGERS
INTO WEDNESDAY OVER SOUTHERN ZONES BUT BY WEDNESDAY AFTERNOON
RIDGING DEVELOPS ENDING PRECIPITATION CHANCES.
GFS BRINGS NEXT SYSTEM INTO IDAHO WEDNESDAY NIGHT AND SEEMS TO BE
TRYING TO CUT OFF UPPER LOW NEAR WEST YELLOWSTONE THURSDAY
MORNING. ECMWF DIGS THIS SAME TROF MUCH FURTHER SOUTH AND SPLITS
THE SYSTEM OVER THE AREA RESULTING IN SOME CLOUD COVER BUT LITTLE
IN THE WAY OF PRECIPITATION OUTSIDE OF MOUNTAIN AREAS. CAUSE OF
THE DIFFERENCES IS DUE TO HANDLING OF STRONG DOWNSTREAM SYSTEM
OVER THE EASTERN US...AND CURRENT GUIDANCE FAVORS THE EC SOLUTION
SO LEFT FORECAST DRY AND WARMED TEMPERATURES JUST A BIT.
ALL THE MODELS IN GOOD AGREEMENT WITH DEVELOPMENT OF STRONG
RIDGING FRIDAY THROUGH NEXT WEEKEND. BOTH MODELS SHOW SATURDAY 850
TEMPERATURES IN THE +6 TO +10C RANGE LEADING TO MIX DOWN
TEMPERATURES WELL INTO THE 50S FOR HIGHS FRIDAY THROUGH SUNDAY.
NOT OUT OF THE QUESTION TO SEE SOME LOWER 60S SATURDAY AND SUNDAY
WITH DRY CONDITIONS UNDER THE RIDGE. CHAMBERS
&&
.AVIATION...
GUSTY SOUTHWEST WINDS IN THE KLVM VICINITY WILL DECREASE THIS
MORNING BEHIND COLD FRONT. SCATTERED SNOW SHOWERS WILL DEVELOP
FROM WEST TO EAST ACROSS THE AREA TODAY AS THE COLD FRONT MOVES
THROUGH. VFR CONDITIONS WILL PREVAIL IN MOST AREAS WITH LOCAL
MVFR CONDITIONS NEAR SNOW SHOWERS. FOOTHILLS AND MOUNTAIN AREAS
WILL SEE MAINLY MVFR CONDITIONS WITH LOCAL IFR OR LOWER CONDITIONS
WITH HEAVIER SNOW SHOWERS EXPECTED IN THESE AREAS. MOUNTAIN AND
PASS OBSCURATION WILL EXIST FOR ALL AREA MOUNTAINS THROUGH
TONIGHT. CHAMBERS
&&
.PRELIMINARY POINT TEMP/POPS...
TDY SUN MON TUE WED THU FRI
-------------------------------------------------------
BIL 041 025/041 022/039 024/037 021/037 023/045 026/051
4/J 32/J 11/B 33/J 11/U 32/J 00/B
LVM 039 020/035 016/035 019/032 013/033 017/038 025/044
7/J 33/W 12/J 44/J 11/U 32/J 11/B
HDN 042 023/043 019/037 022/036 017/035 020/043 023/049
5/W 43/J 11/B 34/J 21/U 33/J 10/B
MLS 044 027/042 021/037 022/036 020/035 020/041 024/047
2/W 22/J 11/U 23/J 21/B 12/J 10/B
4BQ 041 024/038 017/035 020/033 018/032 017/039 020/045
6/W 73/J 11/U 24/J 21/B 12/J 10/B
BHK 041 024/035 016/032 019/031 018/031 016/036 018/040
3/J 22/J 11/U 13/J 21/B 11/B 10/B
SHR 038 020/036 012/034 018/032 015/033 016/039 018/045
7/J 83/J 11/U 44/J 21/U 22/J 10/B
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...WIND ADVISORY IN EFFECT UNTIL 10 AM MST THIS MORNING FOR
ZONES 65-66.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
954 AM EST SAT FEB 23 2013
.SYNOPSIS...
A COMBINATION OF TWO STORM SYSTEMS...ONE TO OUR NORTHWEST AND
ANOTHER MOVING UP THE COAST...WILL BRING US UNSETTLED WEATHER
TODAY WITH PLENTY OF CLOUDS. MOST OF THE AREA WILL SEE RAIN
DEVELOP BY AFTERNOON...BUT SOME WET SNOW IS POSSIBLE ACROSS ONEIDA
COUNTY AND THE CATSKILLS. BY TONIGHT AS COLDER AIR MOVES BACK INTO
OUR AREA...A PERIOD OF FREEZING RAIN IS POSSIBLE OVER THE
CATSKILLS...WITH A GRADUAL TRANSITION FROM RAIN TO SNOW OVER THE
ENTIRE AREA BEFORE ENDING. LIGHT SNOW SHOWERS ARE POSSIBLE SUNDAY
IN CENTRAL NY WITH DRIER WEATHER BY MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
930 AM UPDATE...
CONVOLUTED FCST WITH CWA RMNG IN VRY WK FORCING AND PCPN POPPING
UP AT RANDOM ACRS THE AREA, THO MOST IS CONFINED CLOSER TO H5-H7
LIFT IN THE FINGER LKS REGION. 12Z RAOBS FM KBUF AND KALY SHOWING
VRY LITTLE ICE IN THE CLD, IN AGREEMENT WITH FCST SNDGS FM BUFKIT.
MOST OBS ACRS THE AREA ARE REPORTING SOME FORM OF LIQUID THUS HV
TWEAKED WX GRIDS TO GO RAIN OR DRIZZLE EXCEPT WHERE LOCALES ARE
BLO FZG AND HV ADDED IN A FRZG MENTION. MOISTURE RETURNS IN THE
-10C TO -20C LAYER AFTR ABOUT 18Z THIS AFTN AND HV ADDED IN
SNOW/FLURRY MENTION BACK IN.
BEST CHC FOR SNOW LOOKS TO BE ACRS NRN ONEIDA CNTY LATE THIS AFTN
WITH STRONG CONVERGENCE BRINGING A QUICK 1-2 INCHES LATE TDA.
ELSEWHERE IT LOOKS TO BE A WINTRY MESS FOR MOST OF THE DAY.
LATEST NAM12 HAS COME IN WITH CURRENT SFC LOW LOCATED OFF OF VA/NC
BORDER RMNG SOUTH OF OUR AREA TONIGHT AND VRY MINIMAL QPF
SPREADING INTO SERN PARTS OF CWA THRU TONIGHT. ONSHORE FLOW WL BE
POSSIBLE WITH CHC CONTG FOR LGT PCPN BUT WL IT BE IN THE FORM OF
LGT FZRA OR FZDZ. WL AWAIT ADDNL 12Z GUIDANCE BFR MAKING DECISION
ON WHAT TO DO WITH EXISTING ADVISORY FOR TONIGHT, WHETHER IT BE TO
TWEAK THE AREA OR CANCEL IT ALTOGETHER.
ONLY MINOR TWEAKS MADE TO HRLY T/TD GRIDS AT THIS TIME.
6 AM UPDATE...
THIS MORNING...AN AREA OF PRECIPITATION MAINLY FROM THE NY/PA LINE
NORTH THROUGH THE FINGER LAKES CONTINUES TO MOVE THROUGH OUR AREA.
OVER THE PAST 2 HOURS THE INTENSITY ON RADAR OF THIS PRECIP HAS
INCREASED. THIS IS LIKELY DUE TO SOME SLEET MIXING IN AS EVIDENT
BY LOWER VALUES OF CC ON THE DUAL POL PRODUCTS. THIS IS INDICATING
MIXED HYDROMETEORS AND BASED ON SOUNDINGS AND THIS AREA COINCIDING
WITH HIGHER RETURNS...SLEET IS THE MOST LIKELY P-TYPE HERE. THE
LATEST RUC SEEMS TO OFFER THE BEST HOPE FOR A SHORT TERM FORECAST
BASED ON A LOBE OF VORTICITY AT 500 MB MOVING THROUGH...THAT LINES
UP WELL WITH THE PRECIP. THE RUC MOVES THIS OFF TO THE NORTHEAST
BY 12Z. BASED ON RADAR TRENDS THOUGH MAY SLOW THIS DOWN A TAD.
PRECIP INTENSITY WILL BE RELATIVELY LIGHT AS WILL QPF AMOUNTS. WE
ARE LACKING ICE IN THE CLOUD SO P-TYPE LOOKS TO BE MAINLY RAIN OR
SOME ICE PELLETS EXCEPT ACROSS THE FAR NORTH AND EAST WHERE
SLIGHTLY DEEPER MOISTURE PROFILES ALLOW FOR SOME SNOW. ISOLATED
POCKETS OF FREEZING RAIN ARE POSSIBLE BUT IT APPEARS WHERE THE
LIQUID PRECIP IS MOST LIKELY...TEMPS ARE ALREADY NEAR OR ABOVE
FREEZING. WHERE WE HAVE COLDER SURFACE TEMPS...MOISTURE ALOFT
SUPPORTS MORE SNOW. AFTER THIS MOVES THROUGH WE MAY SEE A LULL FOR
A FEW HOURS FOR MOST OF US.
LATER THIS MORNING/TONIGHT...NEXT FEATURES OF INTEREST WILL BE AN
AREA OF LOW PRESSURE MOVING THROUGH THE GREAT LAKES AND AN AREA OF
LOW PRESSURE NOW TAKING SHAPE OFF THE CAROLINA COAST. OUR AREA
WILL BE IN ON THE SQUEEZE PLAY TODAY WITH INCREASING MOISTURE FROM
BOTH THE WEST (GREAT LAKES SYSTEM) AND EAST (COASTAL SYSTEM). MAIN
ADJUSTMENT WAS TO TRIM BACK POPS IN THE MIDDLE TODAY...AND PUSH
BACK THE BEST SHOT AT WIDESPREAD PRECIPITATION INTO THE 18Z - 22Z
RANGE. OVERALL THOUGH LOOKING AT A FAIRLY LIGHT QPF EVENT WITH
AROUND AMOUNTS RANGING FROM A TENTH TO TWO TENTHS. THE FIRST
TRIGGER FOR PRECIP WILL COME BY LATE MORNING AS A RIBBON OF PVA
SLIDES INTO WESTERN NY...IN THE FLOW AROUND THE PARENT UPPER LOW
OVER THE GREAT LAKES. THIS WILL MOVE ACROSS THE REST OF THE AREA
TOWARD 20Z...AS WE ALSO GETTING INCREASING UPPER LEVEL LIFT OVER
THE FAR SOUTHEAST IN RESPONSE TO THE COASTAL LOW. I RAMP POPS UP
GREATLY IN THE 22Z TO 0Z PERIOD TO SHOW OUR BEST SHOT AT
PRECIPITATION ACROSS MOST OF THE AREA AS THIS HAPPENS.
AS FAR AS P-TYPE GOES...A TONGUE OF WARMER AIR AROUND 800 MB WILL
KEEP US MOSTLY RAIN THROUGH LATE THIS AFTERNOON. THE EXCEPTION
WILL BE ACROSS NORTHERN ONEIDA COUNTY WHERE TEMPS ALOFT NEVER GET
ABOVE 0C...SO AT THE VERY LEAST A RAIN/SNOW MIX IS LIKELY IF NOT
MOSTLY SNOW...ALL DAY. WE COULD SEE UP TO 2 INCHES HERE THROUGH
AFTERNOON ACROSS THE HIGHER TERRAIN. OVER THE FAR EAST SNOW IS
POSSIBLE EARLY BUT EVEN HERE TEMPS ALOFT WARM UP ABOVE 0C AFTER
21Z. DURING THIS TIME SOME AREAS OF FREEZING RAIN ARE POSSIBLE IN
OUR NORMALLY COLDEST SECTIONS...WITH PLAIN RAIN OR A FEW SLEET
PELLETS POSSIBLE ELSEWHERE.
TONIGHT...AS THE COASTAL SYSTEM DEEPENS AND MOVES WELL OUT TO
SEA...COLDER AIR ALOFT WILL RAPIDLY MOVE IN FROM THE WEST. THIS
WILL CHANGE OUR RAIN OVER TO A PERIOD OF LIGHT SNOW BEFORE ENDING
OVERNIGHT. ACCUMS EXPECTED TO BE AROUND AN INCH OR LESS. THE
TRICKY SPOT WILL BE ROUGHLY FROM DELAWARE COUNTY SOUTH THROUGH
WAYNE AND PIKE COUNTIES...WHERE TEMPS ALOFT WILL REMAIN ABOVE 0C
THROUGH 03Z THIS EVENING. NAM SOUNDINGS HAVE REMAINED CONSISTENT
SINCE LAST NIGHT SHOWING SOME BOUNDARY LAYER COOLING DURING THIS
TIME ALLOWING SURFACE TEMPS TO BE NEAR OR SLIGHTLY BELOW FREEZING.
GFS PROFILES COULD NOT BE MORE DIFFERENT WITH TEMPS REMAINING
ABOVE FREEZING AT THE SURFACE...BEFORE A RAPID TRANSITION FROM
RAIN TO SNOW...WITH NO PERIOD OF FREEZING RAIN. SREF PROFILES
PROVIDE LITTLE HELP WITH SOLUTIONS SHOWING A WILD RANGE. BASED ON
CLIMATOLOGY...COORDINATION WITH SURROUNDING WFOS...AND BUYING THAT
THE HIGHER RESOLUTION OF THE NAM THIS CLOSE IN SHOULD BE SUPERIOR TO
THE GFS...ISSUED A WINTER WEATHER ADVISORY FOR THESE AREAS. WE WANT
TO STRESS THIS ADVISORY IS NOT FOR THE SNOWFALL AMOUNTS BUT FOR
THE SHORT WINDOW OF TIME FROM BETWEEN 22Z THROUGH 03Z WHEN WARM
TEMPS ALOFT COMBINED WITH COOLING SURFACE TEMPS WILL ALLOW FOR A
PERIOD OF FREEZING RAIN. LATE TONIGHT WE HAVE PLENTY OF MOISTURE
IN THE LOW LEVELS BY LACK OF MOISTURE IN THE MID LEVELS (NO ICE
CRYSTALS) WILL LIKELY MEAN A FAIRLY RAPID END FROM WEST TO EAST OF
ANY PRECIP.
&&
.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
600 AM UPDATE...
SUNDAY/SUNDAY NIGHT...NOT MUCH CHANGE TO THE PREVIOUS FORECAST.
WE REMAIN UNDER THE INFLUENCE OF THE UPPER LEVEL LOW WITH CHANCES
FOR LIGHT SNOW MAINLY IN CNY BY SUNDAY AFTERNOON/NIGHT. NOT
LOOKING FOR MUCH IN TERMS OF ACCUMS.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
345 AM UPDATE...
WELCOME TO CUTOFF COUNTRY. A PATTERN MORE REMINISCENT OF EARLY
SPRING...THAT IS...AMPLIFIED WITH CUTOFF LOWS...WILL DOMINATE THE
LONG TERM PERIOD OF THE FORECAST. DAYTIME TEMPERATURES THOUGH
WILL NOT STRAY MUCH FROM CLIMATOLOGY.
ECMWF AND GFS AGREE THAT AN UPPER LOW WILL BE SHIFTING ITS WAY UP
THE OHIO VALLEY TUESDAY INTO TUESDAY NIGHT. THE DETAILS ARE A BIT
DIFFERENT AS TO WHAT HAPPENS FROM THERE...BUT BOTH SHOW A VERSION
OF A NORTHERN HIGH PLAINS UPPER TROUGH DIGGING INTO THE MIDWEST
AND CAPTURING/CONSOLIDATING WITH THE ORIGINAL UPPER LOW. WHEN
THAT OCCURS...IT WILL BE STUCK IN OUR VICINITY AND IN ABSOLUTELY
NO RUSH TO GO ANYWHERE THROUGH FRIDAY. FOR US...THAT MEANS PLENTY
OF CLOUD COVER...OCCASIONAL SNOW AND/OR RAIN SHOWERS...AND LITTLE
MOVEMENT IN TEMPERATURES DIURNALLY.
ON THE LEADING EDGE OF THIS PATTERN...MODEL CONSENSUS HAS SHIELD
OF PRECIPITATION MOVING IN A BIT SLOWER THAN PREVIOUS
FORECAST...MAINLY LATE TUESDAY INTO TUESDAY NIGHT. THIS SLOWER
TREND IS NOT A SURPRISE GIVEN AMPLIFIED NATURE TO PATTERN. GRIDS
HAVE BEEN ADJUSTED ACCORDINGLY. PRESSURE GRADIENT BETWEEN LARGE
DEPARTING NEW ENGLAND HIGH AND INCOMING LOW WILL BE QUITE
STEEP...AND I THUS INCREASED WINDS FOR THE TUESDAY NIGHT/EARLY
WEDNESDAY PERIOD. NOT SURE YET HOW MUCH OF THE STRONG WINDS ALOFT
WILL BE ABLE TO MIX DOWN...THE BOUNDARY LAYER MAY BE FAIRLY
STABLE. ONE NOTEWORTHY DIFFERENCE IN THE MODELS IS THAT THE GFS IS
COLDER AT 925MB THAN AT 850MB /WHERE IT IS MAINLY ABOVE FREEZING/
AS THE PRECIPITATION MOVES IN TUESDAY. ECMWF MEANWHILE IS VICE-
VERSA. SO THE GFS WOULD SUGGEST POSSIBLE FREEZING RAIN WHILE THE
ECMWF IS MORE OF A SIMPLE RAIN/SNOW MIX. I HAVE NOT ADDED CHANCE
OF FREEZING RAIN TO GRIDS JUST YET...BUT THIS POTENTIAL WILL HAVE
TO BE ASSESSED AS THE EVENT GETS CLOSER.
&&
.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
12Z UPDATE...
COMPLICATED AVIATION FORECAST DURING THIS TAF PERIOD...WITH REGION
IN MOIST FEED BETWEEN DEVELOPING LOW AROUND THE MID ATLANTIC
COAST...AND ANOTHER LOW IN THE NORTHERN GREAT LAKES. MAINLY MVFR
CIGS TODAY...IN MOST CASES FUEL ALT MINS /AND EVEN IFR FOR
KBGM/...COURTESY OF MOISTURE TRAPPED UNDER INVERSION. PASSING
-SHRA WILL YIELD MVFR VIS AS WELL AT TIMES. BEHIND OCCLUDED FRONT
TONIGHT...SATURATED LAYER GETS SQUEEZED BELOW LOWERING INVERSION
AND IFR CIGS WILL IMPACT MOST TERMINALS THIS EVENING BEFORE LIMITED
IMPROVEMENT TOWARDS DAWN SUNDAY. FREEZING DRIZZLE NOT OUT OF THE
QUESTION...WITH SHALLOW SATURATED LAYER STAYING ON THE WARM SIDE
WHICH MAY PRESENT DIFFICULTY INTRODUCING SNOW CRYSTALS.
.OUTLOOK...
SUN...VFR...MAYBE MVFR IN NY WITH LAKE ENHANCED SNOW SHOWERS.
MON...VFR.
TUE...MVFR/IFR IN RAIN AND/OR SNOW LATE TUE INTO TUE NIGHT.
WED...MVFR IN LAKE ENHANCED SNOW SHOWERS.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 7 AM EST
SUNDAY FOR PAZ040-048-072.
NY...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 7 AM EST
SUNDAY FOR NYZ057-062.
&&
$$
SYNOPSIS...HEDEN
NEAR TERM...HEDEN/PVN
SHORT TERM...HEDEN
LONG TERM...MDP
AVIATION...MDP
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
646 AM EST SAT FEB 23 2013
.SYNOPSIS...
A COMBINATION OF TWO STORM SYSTEMS...ONE TO OUR NORTHWEST AND
ANOTHER MOVING UP THE COAST...WILL BRING US UNSETTLED WEATHER
TODAY WITH PLENTY OF CLOUDS. MOST OF THE AREA WILL SEE RAIN
DEVELOP BY AFTERNOON...BUT SOME WET SNOW IS POSSIBLE ACROSS ONEIDA
COUNTY AND THE CATSKILLS. BY TONIGHT AS COLDER AIR MOVES BACK INTO
OUR AREA...A PERIOD OF FREEZING RAIN IS POSSIBLE OVER THE
CATSKILLS...WITH A GRADUAL TRANSITION FROM RAIN TO SNOW OVER THE
ENTIRE AREA BEFORE ENDING. LIGHT SNOW SHOWERS ARE POSSIBLE SUNDAY
IN CENTRAL NY WITH DRIER WEATHER BY MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
THIS MORNING...AN AREA OF PRECIPITATION MAINLY FROM THE NY/PA LINE
NORTH THROUGH THE FINGER LAKES CONTINUES TO MOVE THROUGH OUR AREA.
OVER THE PAST 2 HOURS THE INTENSITY ON RADAR OF THIS PRECIP HAS INCREASED.
THIS IS LIKELY DUE TO SOME SLEET MIXING IN AS EVIDENT BY LOWER
VALUES OF CC ON THE DUAL POL PRODUCTS. THIS IS INDICATING MIXED
HYDROMETEORS AND BASED ON SOUNDINGS AND THIS AREA COINCIDING WITH
HIGHER RETURNS...SLEET IS THE MOST LIKELY P-TYPE HERE. THE LATEST
RUC SEEMS TO OFFER THE BEST HOPE FOR A SHORT TERM FORECAST BASED
ON A LOBE OF VORTICITY AT 500 MB MOVING THROUGH...THAT LINES UP
WELL WITH THE PRECIP. THE RUC MOVES THIS OFF TO THE NORTHEAST BY
12Z. BASED ON RADAR TRENDS THOUGH MAY SLOW THIS DOWN A TAD. PRECIP
INTENSITY WILL BE RELATIVELY LIGHT AS WILL QPF AMOUNTS. WE ARE LACKING
ICE IN THE CLOUD SO P-TYPE LOOKS TO BE MAINLY RAIN OR SOME ICE
PELLETS EXCEPT ACROSS THE FAR NORTH AND EAST WHERE SLIGHTLY DEEPER
MOISTURE PROFILES ALLOW FOR SOME SNOW. ISOLATED POCKETS OF
FREEZING RAIN ARE POSSIBLE BUT IT APPEARS WHERE THE LIQUID PRECIP
IS MOST LIKELY...TEMPS ARE ALREADY NEAR OR ABOVE FREEZING. WHERE
WE HAVE COLDER SURFACE TEMPS...MOISTURE ALOFT SUPPORTS MORE SNOW.
AFTER THIS MOVES THROUGH WE MAY SEE A LULL FOR A FEW HOURS FOR
MOST OF US.
LATER THIS MORNING/TONIGHT...NEXT FEATURES OF INTEREST WILL BE AN
AREA OF LOW PRESSURE MOVING THROUGH THE GREAT LAKES AND AN AREA OF
LOW PRESSURE NOW TAKING SHAPE OFF THE CAROLINA COAST. OUR AREA
WILL BE IN ON THE SQUEEZE PLAY TODAY WITH INCREASING MOISTURE FROM
BOTH THE WEST (GREAT LAKES SYSTEM) AND EAST (COASTAL SYSTEM). MAIN
ADJUSTMENT WAS TO TRIM BACK POPS IN THE MIDDLE TODAY...AND PUSH
BACK THE BEST SHOT AT WIDESPREAD PRECIPITATION INTO THE 18Z - 22Z
RANGE. OVERALL THOUGH LOOKING AT A FAIRLY LIGHT QPF EVENT WITH
AROUND AMOUNTS RANGING FROM A TENTH TO TWO TENTHS. THE FIRST
TRIGGER FOR PRECIP WILL COME BY LATE MORNING AS A RIBBON OF PVA
SLIDES INTO WESTERN NY...IN THE FLOW AROUND THE PARENT UPPER LOW
OVER THE GREAT LAKES. THIS WILL MOVE ACROSS THE REST OF THE AREA
TOWARD 20Z...AS WE ALSO GETTING INCREASING UPPER LEVEL LIFT OVER
THE FAR SOUTHEAST IN RESPONSE TO THE COASTAL LOW. I RAMP POPS UP
GREATLY IN THE 22Z TO 0Z PERIOD TO SHOW OUR BEST SHOT AT
PRECIPITATION ACROSS MOST OF THE AREA AS THIS HAPPENS.
AS FAR AS P-TYPE GOES...A TONGUE OF WARMER AIR AROUND 800 MB WILL
KEEP US MOSTLY RAIN THROUGH LATE THIS AFTERNOON. THE EXCEPTION
WILL BE ACROSS NORTHERN ONEIDA COUNTY WHERE TEMPS ALOFT NEVER GET
ABOVE 0C...SO AT THE VERY LEAST A RAIN/SNOW MIX IS LIKELY IF NOT
MOSTLY SNOW...ALL DAY. WE COULD SEE UP TO 2 INCHES HERE THROUGH
AFTERNOON ACROSS THE HIGHER TERRAIN. OVER THE FAR EAST SNOW IS
POSSIBLE EARLY BUT EVEN HERE TEMPS ALOFT WARM UP ABOVE 0C AFTER
21Z. DURING THIS TIME SOME AREAS OF FREEZING RAIN ARE POSSIBLE IN
OUR NORMALLY COLDEST SECTIONS...WITH PLAIN RAIN OR A FEW SLEET
PELLETS POSSIBLE ELSEWHERE.
TONIGHT...AS THE COASTAL SYSTEM DEEPENS AND MOVES WELL OUT TO
SEA...COLDER AIR ALOFT WILL RAPIDLY MOVE IN FROM THE WEST. THIS
WILL CHANGE OUR RAIN OVER TO A PERIOD OF LIGHT SNOW BEFORE ENDING
OVERNIGHT. ACCUMS EXPECTED TO BE AROUND AN INCH OR LESS. THE
TRICKY SPOT WILL BE ROUGHLY FROM DELAWARE COUNTY SOUTH THROUGH
WAYNE AND PIKE COUNTIES...WHERE TEMPS ALOFT WILL REMAIN ABOVE 0C
THROUGH 03Z THIS EVENING. NAM SOUNDINGS HAVE REMAINED CONSISTENT
SINCE LAST NIGHT SHOWING SOME BOUNDARY LAYER COOLING DURING THIS
TIME ALLOWING SURFACE TEMPS TO BE NEAR OR SLIGHTLY BELOW FREEZING.
GFS PROFILES COULD NOT BE MORE DIFFERENT WITH TEMPS REMAINING
ABOVE FREEZING AT THE SURFACE...BEFORE A RAPID TRANSITION FROM
RAIN TO SNOW...WITH NO PERIOD OF FREEZING RAIN. SREF PROFILES
PROVIDE LITTLE HELP WITH SOLUTIONS SHOWING A WILD RANGE. BASED ON
CLIMATOLOGY...COORDINATION WITH SURROUNDING WFOS...AND BUYING THAT
THE HIGHER RESOLUTION OF THE NAM THIS CLOSE IN SHOULD BE SUPERIOR TO
THE GFS...ISSUED A WINTER WEATHER ADVISORY FOR THESE AREAS. WE WANT
TO STRESS THIS ADVISORY IS NOT FOR THE SNOWFALL AMOUNTS BUT FOR
THE SHORT WINDOW OF TIME FROM BETWEEN 22Z THROUGH 03Z WHEN WARM
TEMPS ALOFT COMBINED WITH COOLING SURFACE TEMPS WILL ALLOW FOR A
PERIOD OF FREEZING RAIN. LATE TONIGHT WE HAVE PLENTY OF MOISTURE
IN THE LOW LEVELS BY LACK OF MOISTURE IN THE MID LEVELS (NO ICE
CRYSTALS) WILL LIKELY MEAN A FAIRLY RAPID END FROM WEST TO EAST OF
ANY PRECIP.
&&
.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
600 AM UPDATE...
SUNDAY/SUNDAY NIGHT...NOT MUCH CHANGE TO THE PREVIOUS FORECAST.
WE REMAIN UNDER THE INFLUENCE OF THE UPPER LEVEL LOW WITH CHANCES
FOR LIGHT SNOW MAINLY IN CNY BY SUNDAY AFTERNOON/NIGHT. NOT
LOOKING FOR MUCH IN TERMS OF ACCUMS.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
345 AM UPDATE...
WELCOME TO CUTOFF COUNTRY. A PATTERN MORE REMINISCENT OF EARLY
SPRING...THAT IS...AMPLIFIED WITH CUTOFF LOWS...WILL DOMINATE THE
LONG TERM PERIOD OF THE FORECAST. DAYTIME TEMPERATURES THOUGH
WILL NOT STRAY MUCH FROM CLIMATOLOGY.
ECMWF AND GFS AGREE THAT AN UPPER LOW WILL BE SHIFTING ITS WAY UP
THE OHIO VALLEY TUESDAY INTO TUESDAY NIGHT. THE DETAILS ARE A BIT
DIFFERENT AS TO WHAT HAPPENS FROM THERE...BUT BOTH SHOW A VERSION
OF A NORTHERN HIGH PLAINS UPPER TROUGH DIGGING INTO THE MIDWEST
AND CAPTURING/CONSOLIDATING WITH THE ORIGINAL UPPER LOW. WHEN
THAT OCCURS...IT WILL BE STUCK IN OUR VICINITY AND IN ABSOLUTELY
NO RUSH TO GO ANYWHERE THROUGH FRIDAY. FOR US...THAT MEANS PLENTY
OF CLOUD COVER...OCCASIONAL SNOW AND/OR RAIN SHOWERS...AND LITTLE
MOVEMENT IN TEMPERATURES DIURNALLY.
ON THE LEADING EDGE OF THIS PATTERN...MODEL CONSENSUS HAS SHIELD
OF PRECIPITATION MOVING IN A BIT SLOWER THAN PREVIOUS
FORECAST...MAINLY LATE TUESDAY INTO TUESDAY NIGHT. THIS SLOWER
TREND IS NOT A SURPRISE GIVEN AMPLIFIED NATURE TO PATTERN. GRIDS
HAVE BEEN ADJUSTED ACCORDINGLY. PRESSURE GRADIENT BETWEEN LARGE
DEPARTING NEW ENGLAND HIGH AND INCOMING LOW WILL BE QUITE
STEEP...AND I THUS INCREASED WINDS FOR THE TUESDAY NIGHT/EARLY
WEDNESDAY PERIOD. NOT SURE YET HOW MUCH OF THE STRONG WINDS ALOFT
WILL BE ABLE TO MIX DOWN...THE BOUNDARY LAYER MAY BE FAIRLY
STABLE. ONE NOTEWORTHY DIFFERENCE IN THE MODELS IS THAT THE GFS IS
COLDER AT 925MB THAN AT 850MB /WHERE IT IS MAINLY ABOVE FREEZING/
AS THE PRECIPITATION MOVES IN TUESDAY. ECMWF MEANWHILE IS VICE-
VERSA. SO THE GFS WOULD SUGGEST POSSIBLE FREEZING RAIN WHILE THE
ECMWF IS MORE OF A SIMPLE RAIN/SNOW MIX. I HAVE NOT ADDED CHANCE
OF FREEZING RAIN TO GRIDS JUST YET...BUT THIS POTENTIAL WILL HAVE
TO BE ASSESSED AS THE EVENT GETS CLOSER.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
12Z UPDATE...
COMPLICATED AVIATION FORECAST DURING THIS TAF PERIOD...WITH REGION
IN MOIST FEED BETWEEN DEVELOPING LOW AROUND THE MID ATLANTIC
COAST...AND ANOTHER LOW IN THE NORTHERN GREAT LAKES. MAINLY MVFR
CIGS TODAY...IN MOST CASES FUEL ALT MINS /AND EVEN IFR FOR
KBGM/...COURTESY OF MOISTURE TRAPPED UNDER INVERSION. PASSING
-SHRA WILL YIELD MVFR VIS AS WELL AT TIMES. BEHIND OCCLUDED FRONT
TONIGHT...SATURATED LAYER GETS SQUEEZED BELOW LOWERING INVERSION
AND IFR CIGS WILL IMPACT MOST TERMINALS THIS EVENING BEFORE LIMITED
IMPROVEMENT TOWARDS DAWN SUNDAY. FREEZING DRIZZLE NOT OUT OF THE
QUESTION...WITH SHALLOW SATURATED LAYER STAYING ON THE WARM SIDE
WHICH MAY PRESENT DIFFICULTY INTRODUCING SNOW CRYSTALS.
.OUTLOOK...
SUN...VFR...MAYBE MVFR IN NY WITH LAKE ENHANCED SNOW SHOWERS.
MON...VFR.
TUE...MVFR/IFR IN RAIN AND/OR SNOW LATE TUE INTO TUE NIGHT.
WED...MVFR IN LAKE ENHANCED SNOW SHOWERS.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 7 AM EST
SUNDAY FOR PAZ040-048-072.
NY...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 7 AM EST
SUNDAY FOR NYZ057-062.
&&
$$
SYNOPSIS...HEDEN
NEAR TERM...HEDEN
SHORT TERM...HEDEN
LONG TERM...MDP
AVIATION...MDP
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
610 AM EST SAT FEB 23 2013
.SYNOPSIS...
A COMBINATION OF TWO STORM SYSTEMS...ONE TO OUR NORTHWEST AND
ANOTHER MOVING UP THE COAST...WILL BRING US UNSETTLED WEATHER
TODAY WITH PLENTY OF CLOUDS. MOST OF THE AREA WILL SEE RAIN
DEVELOP BY AFTERNOON...BUT SOME WET SNOW IS POSSIBLE ACROSS ONEIDA
COUNTY AND THE CATSKILLS. BY TONIGHT AS COLDER AIR MOVES BACK INTO
OUR AREA...A PERIOD OF FREEZING RAIN IS POSSIBLE OVER THE
CATSKILLS...WITH A GRADUAL TRANSITION FROM RAIN TO SNOW OVER THE
ENTIRE AREA BEFORE ENDING. LIGHT SNOW SHOWERS ARE POSSIBLE SUNDAY
IN CENTRAL NY WITH DRIER WEATHER BY MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
THIS MORNING...AN AREA OF PRECIPITATION MAINLY FROM THE NY/PA LINE
NORTH THROUGH THE FINGER LAKES CONTINUES TO MOVE THROUGH OUR AREA.
OVER THE PAST 2 HOURS THE INTENSITY ON RADAR OF THIS PRECIP HAS INCREASED.
THIS IS LIKELY DUE TO SOME SLEET MIXING IN AS EVIDENT BY LOWER
VALUES OF CC ON THE DUAL POL PRODUCTS. THIS IS INDICATING MIXED
HYDROMETEORS AND BASED ON SOUNDINGS AND THIS AREA COINCIDING WITH
HIGHER RETURNS...SLEET IS THE MOST LIKELY P-TYPE HERE. THE LATEST
RUC SEEMS TO OFFER THE BEST HOPE FOR A SHORT TERM FORECAST BASED
ON A LOBE OF VORTICITY AT 500 MB MOVING THROUGH...THAT LINES UP
WELL WITH THE PRECIP. THE RUC MOVES THIS OFF TO THE NORTHEAST BY
12Z. BASED ON RADAR TRENDS THOUGH MAY SLOW THIS DOWN A TAD. PRECIP
INTENSITY WILL BE RELATIVELY LIGHT AS WILL QPF AMOUNTS. WE ARE LACKING
ICE IN THE CLOUD SO P-TYPE LOOKS TO BE MAINLY RAIN OR SOME ICE
PELLETS EXCEPT ACROSS THE FAR NORTH AND EAST WHERE SLIGHTLY DEEPER
MOISTURE PROFILES ALLOW FOR SOME SNOW. ISOLATED POCKETS OF
FREEZING RAIN ARE POSSIBLE BUT IT APPEARS WHERE THE LIQUID PRECIP
IS MOST LIKELY...TEMPS ARE ALREADY NEAR OR ABOVE FREEZING. WHERE
WE HAVE COLDER SURFACE TEMPS...MOISTURE ALOFT SUPPORTS MORE SNOW.
AFTER THIS MOVES THROUGH WE MAY SEE A LULL FOR A FEW HOURS FOR
MOST OF US.
LATER THIS MORNING/TONIGHT...NEXT FEATURES OF INTEREST WILL BE AN
AREA OF LOW PRESSURE MOVING THROUGH THE GREAT LAKES AND AN AREA OF
LOW PRESSURE NOW TAKING SHAPE OFF THE CAROLINA COAST. OUR AREA
WILL BE IN ON THE SQUEEZE PLAY TODAY WITH INCREASING MOISTURE FROM
BOTH THE WEST (GREAT LAKES SYSTEM) AND EAST (COASTAL SYSTEM). MAIN
ADJUSTMENT WAS TO TRIM BACK POPS IN THE MIDDLE TODAY...AND PUSH
BACK THE BEST SHOT AT WIDESPREAD PRECIPITATION INTO THE 18Z - 22Z
RANGE. OVERALL THOUGH LOOKING AT A FAIRLY LIGHT QPF EVENT WITH
AROUND AMOUNTS RANGING FROM A TENTH TO TWO TENTHS. THE FIRST
TRIGGER FOR PRECIP WILL COME BY LATE MORNING AS A RIBBON OF PVA
SLIDES INTO WESTERN NY...IN THE FLOW AROUND THE PARENT UPPER LOW
OVER THE GREAT LAKES. THIS WILL MOVE ACROSS THE REST OF THE AREA
TOWARD 20Z...AS WE ALSO GETTING INCREASING UPPER LEVEL LIFT OVER
THE FAR SOUTHEAST IN RESPONSE TO THE COASTAL LOW. I RAMP POPS UP
GREATLY IN THE 22Z TO 0Z PERIOD TO SHOW OUR BEST SHOT AT
PRECIPITATION ACROSS MOST OF THE AREA AS THIS HAPPENS.
AS FAR AS P-TYPE GOES...A TONGUE OF WARMER AIR AROUND 800 MB WILL
KEEP US MOSTLY RAIN THROUGH LATE THIS AFTERNOON. THE EXCEPTION
WILL BE ACROSS NORTHERN ONEIDA COUNTY WHERE TEMPS ALOFT NEVER GET
ABOVE 0C...SO AT THE VERY LEAST A RAIN/SNOW MIX IS LIKELY IF NOT
MOSTLY SNOW...ALL DAY. WE COULD SEE UP TO 2 INCHES HERE THROUGH
AFTERNOON ACROSS THE HIGHER TERRAIN. OVER THE FAR EAST SNOW IS
POSSIBLE EARLY BUT EVEN HERE TEMPS ALOFT WARM UP ABOVE 0C AFTER
21Z. DURING THIS TIME SOME AREAS OF FREEZING RAIN ARE POSSIBLE IN
OUR NORMALLY COLDEST SECTIONS...WITH PLAIN RAIN OR A FEW SLEET
PELLETS POSSIBLE ELSEWHERE.
TONIGHT...AS THE COASTAL SYSTEM DEEPENS AND MOVES WELL OUT TO
SEA...COLDER AIR ALOFT WILL RAPIDLY MOVE IN FROM THE WEST. THIS
WILL CHANGE OUR RAIN OVER TO A PERIOD OF LIGHT SNOW BEFORE ENDING
OVERNIGHT. ACCUMS EXPECTED TO BE AROUND AN INCH OR LESS. THE
TRICKY SPOT WILL BE ROUGHLY FROM DELAWARE COUNTY SOUTH THROUGH
WAYNE AND PIKE COUNTIES...WHERE TEMPS ALOFT WILL REMAIN ABOVE 0C
THROUGH 03Z THIS EVENING. NAM SOUNDINGS HAVE REMAINED CONSISTENT
SINCE LAST NIGHT SHOWING SOME BOUNDARY LAYER COOLING DURING THIS
TIME ALLOWING SURFACE TEMPS TO BE NEAR OR SLIGHTLY BELOW FREEZING.
GFS PROFILES COULD NOT BE MORE DIFFERENT WITH TEMPS REMAINING
ABOVE FREEZING AT THE SURFACE...BEFORE A RAPID TRANSITION FROM
RAIN TO SNOW...WITH NO PERIOD OF FREEZING RAIN. SREF PROFILES
PROVIDE LITTLE HELP WITH SOLUTIONS SHOWING A WILD RANGE. BASED ON
CLIMATOLOGY...COORDINATION WITH SURROUNDING WFOS...AND BUYING THAT
THE HIGHER RESOLUTION OF THE NAM THIS CLOSE IN SHOULD BE SUPERIOR TO
THE GFS...ISSUED A WINTER WEATHER ADVISORY FOR THESE AREAS. WE WANT
TO STRESS THIS ADVISORY IS NOT FOR THE SNOWFALL AMOUNTS BUT FOR
THE SHORT WINDOW OF TIME FROM BETWEEN 22Z THROUGH 03Z WHEN WARM
TEMPS ALOFT COMBINED WITH COOLING SURFACE TEMPS WILL ALLOW FOR A
PERIOD OF FREEZING RAIN. LATE TONIGHT WE HAVE PLENTY OF MOISTURE
IN THE LOW LEVELS BY LACK OF MOISTURE IN THE MID LEVELS (NO ICE
CRYSTALS) WILL LIKELY MEAN A FAIRLY RAPID END FROM WEST TO EAST OF
ANY PRECIP.
&&
.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
600 AM UPDATE...
SUNDAY/SUNDAY NIGHT...NOT MUCH CHANGE TO THE PREVIOUS FORECAST.
WE REMAIN UNDER THE INFLUENCE OF THE UPPER LEVEL LOW WITH CHANCES
FOR LIGHT SNOW MAINLY IN CNY BY SUNDAY AFTERNOON/NIGHT. NOT
LOOKING FOR MUCH IN TERMS OF ACCUMS.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
345 AM UPDATE...
WELCOME TO CUTOFF COUNTRY. A PATTERN MORE REMINISCENT OF EARLY
SPRING...THAT IS...AMPLIFIED WITH CUTOFF LOWS...WILL DOMINATE THE
LONG TERM PERIOD OF THE FORECAST. DAYTIME TEMPERATURES THOUGH
WILL NOT STRAY MUCH FROM CLIMATOLOGY.
ECMWF AND GFS AGREE THAT AN UPPER LOW WILL BE SHIFTING ITS WAY UP
THE OHIO VALLEY TUESDAY INTO TUESDAY NIGHT. THE DETAILS ARE A BIT
DIFFERENT AS TO WHAT HAPPENS FROM THERE...BUT BOTH SHOW A VERSION
OF A NORTHERN HIGH PLAINS UPPER TROUGH DIGGING INTO THE MIDWEST
AND CAPTURING/CONSOLIDATING WITH THE ORIGINAL UPPER LOW. WHEN
THAT OCCURS...IT WILL BE STUCK IN OUR VICINITY AND IN ABSOLUTELY
NO RUSH TO GO ANYWHERE THROUGH FRIDAY. FOR US...THAT MEANS PLENTY
OF CLOUD COVER...OCCASIONAL SNOW AND/OR RAIN SHOWERS...AND LITTLE
MOVEMENT IN TEMPERATURES DIURNALLY.
ON THE LEADING EDGE OF THIS PATTERN...MODEL CONSENSUS HAS SHIELD
OF PRECIPITATION MOVING IN A BIT SLOWER THAN PREVIOUS
FORECAST...MAINLY LATE TUESDAY INTO TUESDAY NIGHT. THIS SLOWER
TREND IS NOT A SURPRISE GIVEN AMPLIFIED NATURE TO PATTERN. GRIDS
HAVE BEEN ADJUSTED ACCORDINGLY. PRESSURE GRADIENT BETWEEN LARGE
DEPARTING NEW ENGLAND HIGH AND INCOMING LOW WILL BE QUITE
STEEP...AND I THUS INCREASED WINDS FOR THE TUESDAY NIGHT/EARLY
WEDNESDAY PERIOD. NOT SURE YET HOW MUCH OF THE STRONG WINDS ALOFT
WILL BE ABLE TO MIX DOWN...THE BOUNDARY LAYER MAY BE FAIRLY
STABLE. ONE NOTEWORTHY DIFFERENCE IN THE MODELS IS THAT THE GFS IS
COLDER AT 925MB THAN AT 850MB /WHERE IT IS MAINLY ABOVE FREEZING/
AS THE PRECIPITATION MOVES IN TUESDAY. ECMWF MEANWHILE IS VICE-
VERSA. SO THE GFS WOULD SUGGEST POSSIBLE FREEZING RAIN WHILE THE
ECMWF IS MORE OF A SIMPLE RAIN/SNOW MIX. I HAVE NOT ADDED CHANCE
OF FREEZING RAIN TO GRIDS JUST YET...BUT THIS POTENTIAL WILL HAVE
TO BE ASSESSED AS THE EVENT GETS CLOSER.
&&
.AVIATION /10Z SATURDAY THROUGH WEDNESDAY/...
06Z UPDATE...
COMPLICATED AVIATION FORECAST DURING THIS TAF PERIOD...WITH REGION
IN MOIST FEED BETWEEN DEVELOPING LOW AROUND THE MID ATLANTIC
COAST...AND ANOTHER LOW IN THE NORTHERN GREAT LAKES. LOW END VFR
TO MVFR CIGS...COURTESY OF SHALLOW MOISTURE WHICH WILL
OCCASIONALLY YIELD PATCHY FREEZING DRIZZLE KAVP-KBGM-KELM LATER
THIS MORNING...BRIEF IFR CIG ALSO NOT OUT OF THE QUESTION LATER
THIS MORNING FOR KBGM /AFTER 12Z/. CIGS GENERALLY STAY IN MVFR
CATEGORY WITH LIGHT RAIN OR DRIZZLE DURING THE DAY CAUSING MVFR
VIS AS OCCLUDED FRONT PASSES OVERHEAD WITH CONTINUED SHALLOW
MOISTURE. BEHIND OCCLUDED FRONT TONIGHT...SATURATED LAYER GETS
SQUEEZED BELOW LOWERING INVERSION AND IFR CIGS MAY IMPACT MOST
TERMINALS. FREEZING DRIZZLE MAY ALSO RE-ENTER THE PICTURE.
.OUTLOOK...
LATE SAT NGT...MVFR/IFR IN MIXED PCPN.
SUN...VFR...MAYBE MVFR IN NY WITH LAKE ENHANCED SNOW SHOWERS.
MON...VFR.
TUE...MVFR/IFR IN RAIN AND/OR SNOW.
WED...MVFR IN LAKE ENHANCED SNOW SHOWERS.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 7 AM EST
SUNDAY FOR PAZ040-048-072.
NY...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 7 AM EST
SUNDAY FOR NYZ057-062.
&&
$$
SYNOPSIS...HEDEN
NEAR TERM...HEDEN
SHORT TERM...HEDEN
LONG TERM...MDP
AVIATION...MDP
AREA FORECAST DISCUSSION...UPDATED
NWS MORRISTOWN TN
1017 AM EST SAT FEB 23 2013
.DISCUSSION...
RAIN HAS EXITED THE AREA...AND A SLOW MOVING FRONT WILL BE BRINGING
DRIER AIR FROM THE WEST THROUGH THE DAY. SATELLITE SHOWS BROKEN
CLOUDS NORTHWEST...AND THE LATEST RUC SHOWS RH CONTINUING TO
DECREASE THROUGH THE AFTERNOON. THE 12Z OHX SOUNDING SHOWS A THIN
MOIST LAYER...HOWEVER DRY ADVECTION WILL BE WEAK AS WINDS IN THIS
LAYER ARE LIGHT. THE TRICKY PART WILL BE HOW MUCH TEMPS WILL RISE
THROUGH BROKEN CLOUDS BEFORE SUNSET. THE LATEST 06Z GFS MOS
GUIDANCE AND LAMP GUIDANCE ARE COOLER THAN THE CURRENT
FORECAST...ESPECIALLY NORTH...SO WILL MAKE A SLIGHT DOWNWARD
ADJUSTMENT TO TEMPS. LOWER 60S WILL STILL BE POSSIBLE IN THE
SOUTHERN VALLEY...WITH MID TO UPPER 50S NORTH AND CENTRAL.
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
DGS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
530 AM CST SAT FEB 23 2013
.SHORT TERM...TODAY THROUGH MONDAY NIGHT
319 AM CST SAT FEB 23 2013
FORECAST CHALLENGES GOING THROUGH EARLY NEXT WEEK REVOLVE AROUND
WHEN THE FLURRIES/SKIES CLEAR OUT TODAY/TONIGHT ALONG WITH WHEN THE
NEXT ROUND OF LIGHT SNOW MAY MOVE IN ON MONDAY.
CYCLONIC FLOW FROM THE SURFACE THROUGH THE UPPER ATMOSPHERE WILL
LINGER ACROSS THE REGION FOR MUCH OF TODAY BEFORE A SURFACE TO
UPPER LEVEL RIDGE AXIS PROPAGATES IN FROM THE WEST TONIGHT. WITH
THE CYCLONIC FLOW HANGING ON FOR MUCH OF TODAY...EXPECT THAT THE
CLOUD COVER AND FLURRIES/SNOW SHOWERS WILL CONTINUE AS WELL AND
THAT THE DRY AIR TO THE SOUTHWEST WILL STRUGGLE TO MOVE IN. BY 00Z
TONIGHT...THE 23.07Z RAP HAS THE SURFACE RIDGE ALIGNED ALONG THE
MISSISSIPPI RIVER...SO AT LEAST EXPECT THAT THE FLURRIES WILL HAVE
ENDED BY THEN ALONG AND WEST OF THE RIVER. HOWEVER...CLOUD COVER
MAY LINGER WITH THE UPPER RIDGE STILL IN THE DAKOTAS. HAVE PLAYED
CLOUD COVER A BIT ON THE PESSIMISTIC SIDE THROUGH TONIGHT AS A
RESULT.
BEYOND THIS THE PATTERN IS FAIRLY QUIET THROUGH THE REST OF THE
WEEKEND AS THE RIDGE SHIFTS TO THE EAST WITH TEMPERATURES AND
CLOUD COVER THE ONLY ISSUES TO CONTEND WITH. THERE IS NOT MUCH IN
THE WAY OF LOW LEVEL COLD AIR ADVECTION KICKING IN BEHIND THIS
SYSTEM...SO EXPECT THAT TEMPERATURES WILL REMAIN NEAR NORMAL
THROUGH MONDAY NIGHT.
THE FOCUS THEN GOES TO THE NEXT SYSTEM THAT COULD IMPACT THE AREA
WHICH IS A COMBINATION OF A NORTHERN STREAM WEAKENING MID LEVEL
SHORT WAVE TROUGH AND A SOUTHERN STREAM DEEPENING LOW. THE TREND
CONTINUES TO BE TO GO SLOWER WITH THE NORTHERN STREAM SHORT WAVE
AS A BLOCKING RIDGE ALONG THE ATLANTIC COAST STALLS OUT THE FLOW.
THE SURFACE REFLECTION FROM THIS SYSTEM IS A TROUGH THAT TRACKS
ACROSS THE DAKOTAS AND STALLS ACROSS MINNESOTA AS THE SOUTHERN
STREAM SYSTEM STARTS TO DEEPEN. THE 23.00Z GFS IS THE MOST ROBUST
WITH QPF EXTENDING NORTH ALONG THIS SURFACE TROUGH WHILE THE REST
OF THE GUIDANCE IS DRY. THEREFORE...HAVE BACKED OFF ON
PRECIPITATION CHANCES FOR MONDAY NIGHT AND KEPT THEM RELEGATED TO
PORTIONS OF SOUTH CENTRAL MINNESOTA INTO NORTHEAST IOWA.
.LONG TERM...TUESDAY THROUGH FRIDAY
319 AM CST SAT FEB 23 2013
THIS AFOREMENTIONED SOUTHERN STREAM SYSTEM APPEARS TO BE COMING
TOGETHER BY TUESDAY WITH THE 23.00Z GUIDANCE LOCKING IN ON A MORE
SOUTHERN TRACK WITH THIS SURFACE LOW. THE 23.00Z GFS/ECMWF/GEM ALL
ADVERTISE THIS LOW RUNNING FROM ST LOUIS OVER TO INDIANAPOLIS
TUESDAY WHICH SHOULD KEEP THE MAIN BAND OF SNOW OFF TO THE
SOUTHEAST. THE 23.00Z GFS IS FURTHEST TO THE NORTHWEST WHILE THE
GEM/ECMWF ARE NEARLY IDENTICAL WITH THEIR TRACK. HAVE BACKED OFF
ON SNOW CHANCES FOR TUESDAY ACROSS SOUTHWEST WISCONSIN AS A
RESULT. AFTER THIS SYSTEM MOVES THROUGH...ANOTHER MID LEVEL TROUGH
WILL DIG DOWN THROUGH THE NORTHWEST FLOW AND REINFORCE THE CUT OFF
CLOSED LOW ACROSS THE EASTERN US. THIS WILL KEEP CYCLONIC FLOW IN
PLACE ACROSS THE REGION THROUGH THURSDAY WITH SOME LIGHT SNOW
POSSIBLE. THE 23.00Z GEM IS THE DRIEST OF THE GUIDANCE AND FOCUSES
THIS TROUGH FURTHER TO THE SOUTH AND WOULD KEEP THE REGION ON THE
DRY SIDE. DESPITE THESE HIGHLY AMPLIFIED SYSTEMS MOVING THROUGH
THE UPPER MIDWEST...THE MAIN POOL OF COLD ARCTIC AIR IS CONFINED
TO FAR NORTHERN CANADA WITH 850MB TEMPERATURES IN THE 0C TO -10C
RANGE ACROSS THE SOUTHERN HALF OF CANADA. THUS...IT DOES NOT LOOK
LIKE TEMPERATURES WILL TAKE MUCH OF A DIP AROUND HERE AS THE
NORTHERLY FLOW SETS UP TOWARD MID WEEK.
&&
.AVIATION...TODAY AND TONIGHT.
530 AM CST SAT FEB 23 2013
MVFR CIGS AND LCL MVFR VSBYS IN -SN WILL GIVE WAY TO VFR CIGS/VSBYS
THIS MORNING AS THE BROAD SFC-MID LEVEL LOW AND ITS CIRCULATION
CENTERED OVER NORTHERN LK MI CONTINUES TO DRIFT OFF TO THE EAST
TODAY. BIGGER QUESTION IS HOW QUICKLY WILL THE CLOUDS DECREASE/
3K-5K FT CLOUD DECKS BECOME SCT THIS AFTERNOON OR EVENING. FOG-
PRODUCT IMAGERY SHOWING THE WESTERN EDGE OF THE CLOUDS NEAR AK
KBDH-KULM-KMCW LINE AT 11Z...MAKING SOME PROGRESS EAST WITH WESTERLY
SFC-925MB FLOW. HOWEVER MODELS HANG ONTO PLENTIFUL SFC-850MB RH INTO
THIS EVENING AT THE TAF SITES. LEFT CLOUDS BKN THRU TODAY WITH
CLOUDS BECOMING SCT DURING THE EVENING. WINDS WILL BE LIGHT TONIGHT.
WITH DECREASING CLOUDS OVER THE FRESH SNOW...THE LINGERING VERY LOW
LEVEL/BOUNDARY LAYER MOISTURE UNDER A STRENGTHENING SFC-925MB
INVERSION IS CONCERN FOR BR DEVELOPMENT LATE TONIGHT...ESPECIALLY AT
SITES LIKE KRST. INTRODUCED SOME MVFR BR AT KRST AFTER 07Z.
FAVORABLE SET-UP FOR RIMING/HOAR FROST FORMATION LATER TONIGHT INTO
SUN MORNING AT SITES WHERE ANY FOG DOES FORM.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
319 AM CST SAT FEB 23 2013
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM....HALBACH
AVIATION.....RRS
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
330 PM MST SAT FEB 23 2013
.SHORT TERM....CURRENT WATER VAPOR AND Q-G ANALYSIS SHOWS A
STRONG STORM SYSTEM CARVING OUT ACROSS THE GREAT BASIN. LATEST
MODEL TRENDS FROM THE 12Z NAM...GFS...GEM AND EVEN WRF HAVE SHOWN
A SLIGHT NORTHWARD SHIFT IN AREAS OF BEST LIFT AND HEAVIER
SNOWFALL. HOWEVER...12Z ECMWF STILL MAINTAINED A PERSISTENT AND
PREFERRED SOLUTION BUT AT THE SAME TIME HAS INCREASED SNOWFALL
AMOUNTS AN INCH OR TWO MORE THAN THE 00Z RUN. NCEP FORECASTERS
WITH ACCESS TO 00Z EC ENSEMBLE MEMBERS NOTED THAT SOME UNCERTAINTY
EVEN REGARDED THE SLIGHTLY FARTHER SOUTH ECMWF SOLUTION...BUT Q-G
HEIGHT FALL ANALYSIS FROM THE RUC INDICATES THE OPERATION ECMWF
SEEMS QUITE REASONABLE. THE ONLY ARGUMENT WOULD BE IF A MID LEVEL
CIRCULATION CENTER PERHAPS RELATED TO LARGER LATENT HEAT RELEASE
WOULD RESULT IN A MORE NORTHERLY SOLUTION. AT THIS TIME...HAVE
STILL LEANED HEAVILY TOWARD THE ECMWF...BUT ALSO INCORPORATED A
BIT OF THE MESOSCALE/SREF MODEL SOLUTIONS.
ALL OF THESE FACTORS ADD UP TO A HIGH POTENTIAL FOR A HEAVY SNOW
EVENT. THEY INCLUDE...NEUTRAL STABILITY PROFILES...AVERAGE OF
25-30 KTS OF NNE UPSLOPE FLOW...DEEP UPSLOPE COMPONENT WELL ABOVE
MOUNTAIN TOP...GOOD MICROPHYSICS WITH LARGE OMEGA THROUGH THE
DENDRITIC GROWTH REGION...AND A 12-18 HOUR PERIOD OF MODERATE Q-G
VERTICAL MOTION. THIS ALL SUPPORTS THE UPGRADE OF BLIZZARD WATCHES
TO WARNING...WINTER STORM WATCHES TO WINTER STORM WARNINGS...AND
MOST OTHER LOCATIONS TO WINTER WEATHER ADVISORIES FOR SNOW AND
BLOWING SNOW. THE OVERALL BLENDING USING A MAJORITY OF THE ECMWF
WITH A LITTLE BIT OF MESOSCALE/SREF MODELS SUPPORT THE FOLLOWING
AMOUNTS...6-10 INCHES FOR DENVER/BOULDER AREA...8-12 INCHES PALMER
DIVIDE...7-14 INCHES FOOTHILLS...AND 4-8 INCHES THROUGH SOUTHERN
WELD...MORGAN...TOWARD WASHINGTON/LINCOLN COUNTY.
.LONG TERM...THE BRUNT OF SUNDAY`S STORM SHOULD BE GETTING CLOSE
TO ENDING BY THE BEGINNING OF THE LONG TERM PERIOD 25/00Z. THERE
WILL PROBABLY STILL BE SOME SNOW OVER THE SOUTHEAST THIRD OR SO OF
THE CWA DURING THE EVENING BUT THAT WILL FLUSH OUT TOWARDS MORNING.
SURFACE PRESSURE GRADIENTS WILL REMAIN SUFFICIENT TO KEEP GUSTY
WINDS OVER MANY LOWER ELEVATIONS IN THE EVENING BUT THESE TOO WILL
SETTLE DOWN OVERNIGHT. ONLY A QUICK BREAK IN THINGS AS A SHORT
WAVE RIDGE MOVES IN FOR MONDAY WITH THE NEXT PACIFIC SYSTEM
IMPACTING OUR WEATHER ON TUESDAY. THIS WILL BE MAINLY A MOUNTAIN
EVENT BUT ENOUGH QG LIFT BLEEDS OVER THE HILLS TO BRING A THREAT
OF PRECIPITATION TO THE PLAINS TUESDAY. ANOTHER WEAKER SYSTEM IS
PROGGED TO PUSH OVER THE CENTRAL ROCKIES THURSDAY...AGAIN BEING
MAINLY A PRECIPITATION PRODUCER FOR THE HIGH COUNTRY. TEMPERATURES
WILL REMAIN BELOW NORMAL THROUGH MOST OF THE WEEK BUT SHOULD
APPROACH NORMAL TOWARD WEEK`S AS A STRONG RIDGE ALOFT BUILDS INTO
THE GREAT BASIN. THE MOUNTAINS AND FOOTHILLS WILL ALSO EXPERIENCE
SOME WINDY PERIODS AS THE FLOW ALOFT BECOMES NORTHWESTERLY.
&&
.AVIATION...SIGNIFICANT AVIATION IMPACTS EXPECTED FROM THIS
WINTER STORM. CEILINGS AND VISIBILITIES WILL TUMBLE TONIGHT AND
REMAIN VERY LOW THROUGH MOST OF SUNDAY. ONSET TIMING OF THIS IS
STILL RATHER DIFFICULT...BUT WE SHOULD SEE SNOW DEVELOPING IN THE
FRONT RANGE AIRPORTS MOST LIKELY BETWEEN 05Z AND 08Z...WITH VLIFR
CONDITIONS BY 09Z-11Z WHEN SNOWFALL RATES INCREASE TO AROUND 1
INCH PER. THE HEAVY SNOW WILL LIKELY CONTINUE THROUGH ABOUT 20Z
SUNDAY BEFORE CONDITIONS SLOWLY IMPROVE. GUSTS UP TO 30 KTS AT
KDEN WITH CONSIDERABLE BLOWING AND DRIFTING SNOW AND POOR
VISIBILITIES CLOSE TO ONE QUARTER MILE FOR SEVERAL HOURS DURING
THE HEAVIEST SNOW 11Z-20Z...THEN GRADUAL IMPROVEMENT.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 5 AM TO 5 PM MST SUNDAY FOR COZ048-
050-051.
WINTER STORM WARNING FROM MIDNIGHT TONIGHT TO 5 PM MST SUNDAY
FOR COZ035-036-039-040.
WINTER WEATHER ADVISORY UNTIL 5 PM MST SUNDAY FOR COZ031-033-034.
WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 5 PM MST SUNDAY
FOR COZ038-042.
WINTER STORM WARNING FROM 2 AM TO 5 PM MST SUNDAY FOR COZ043-044.
BLIZZARD WARNING FROM 2 AM TO 5 PM MST SUNDAY FOR COZ041-045.
BLIZZARD WARNING FROM 5 AM TO 5 PM MST SUNDAY FOR COZ046-047-049.
&&
$$
SHORT TERM...BARJENBRUCH
LONG TERM....ET
AVIATION...BARJENBRUCH
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
128 PM CST SAT FEB 23 2013
.SYNOPSIS...
ISSUED AT 519 AM CST SAT FEB 23 2013
06Z SFC ANALYSIS HAS AN OCCLUDED LOW NEARING THE MACKINAC STRAITS
WHILE HIGH PRESSURE WAS ACROSS THE PLAINS. DEW POINTS WERE IN THE
SINGLE DIGITS AND TEENS ACROSS THE PLAINS WITH 20S AND 30S ACROSS
THE GREAT LAKES AND OHIO VALLEY.
&&
.UPDATE...
ISSUED AT 127 PM CST SAT FEB 23 2013
WITH THE CLEARING OF THE CLOUDS HAVE BOOSTED MAX TEMPS A
LITTLE...ESPECIALLY ACROSS THE WESTERN HALF OF THE AREA WHERE
SUNSHINE HAS BEEN OUT THE LONGEST. WITH THE CLEARING OF THESE LOW
CLOUDS THERE IS A NEW CONCERN FOR TONIGHT. WILL BE LOOKING AT HOW
MUCH COLDER TO GO WITH MIN TEMPS...BUT HAVE NOT MADE ANY
ADJUSTMENTS YET. HOWEVER...THIS DOES RAISE THE SPECTER OF FOG AS
WE SAW LAST NIGHT OVER EASTERN NEBRASKA. THUS...HAVE PUT IN AREAS
OF FOG FOR TONIGHT AND EARLY SUNDAY. LIKELY THE FOG WILL BE
ACCOMPANIED BY LOW CLOUDS AS WELL...BUT WILL ALSO REVISIT THIS
THIS AFTERNOON. LE
&&
.SHORT TERM...TODAY AND TONIGHT
ISSUED AT 519 AM CST SAT FEB 23 2013
A COMBINATION OF CYCLONIC FLOW ALOFT AND VORT MAXES...MAINLY AT 700
MB IS PRODUCING FLURRIES/LIGHT SNOW ACROSS THE NORTHERN PART OF THE
CWFA AND UP INTO MINNESOTA. THE RAP TRENDS HAVE THE 700MB SHORTWAVE
ROTATING THROUGH DURING THE DAY WITH NEAR CONTINUOUS 700MB VORT
MAXES ROTATING THROUGH. THUS FLURRIES/VERY LIGHT SNOW WILL BE SEEN
ACROSS ROUGHLY THE NORTHERN HALF DURING THE MORNING.
FCST SOUNDINGS SHOW A DRYING ALOFT OCCURRING DURING THE AFTERNOON SO
ANY FLURRIES/LIGHT SNOW WILL GRADUALLY END.
BASED ON 0.5KM CONDENSATION PRESSURES/WIND...CLOUDS SHOULD STAY PUT
FOR MUCH OF THE MORNING BEFORE CLEARING STARTS FROM WEST TO EAST
DURING THE AFTERNOON. THE COLD POOL ALOFT MAY HELP GENERATE SOME
DIURNAL CLOUDS WHICH MAY SLOW THE RATE OF CLEARING DURING THE
AFTERNOON HOURS. ..08..
.LONG TERM...SUNDAY THROUGH NEXT FRIDAY
ISSUED AT 519 AM CST SAT FEB 23 2013
THE EXTENDED STORM IS IN MUCH BETTER AGREEMENT IN MODEL FORECASTS
TONIGHT...AND IS FOCUSED ON A SURFACE LOW TRACK FROM OK/AR THROUGH
INDIANA MONDAY INTO TUESDAY. THE STORM SHOULD ONCE AGAIN HAVE A
BROAD UPPER LOW ASSOCIATED WITH IT...AND BY IN LARGE...THE UPPER LOW
SHOULD DOMINATE THE AREAL PLACEMENT OF RAIN AND SNOW. THE BIGGEST
DIFFERENCE IN MODELS TONIGHT...IS THAT NO MODEL FORECASTS AN
INTENSIFYING SURFACE LOW...OR EVEN A STRONG OCCLUDED LOW AS IT MOVES
PAST THE REGION. THIS WOULD INDICATE A MUCH LOWER RISK FOR A STRONG
WIND DRIVEN SNOW/BLIZZARD THAN THE EARLIER 12Z ECMWF WOULD HAVE
INDICATED. DESPITE THIS...THE STORM SHOULD BE ABLE TO PRODUCE A
HEALTHY DEFORMATION ZONE...AND ALL MODELS BRUSH THIS FORCING THROUGH
THE CENTRAL AND SOUTHERN CWA...AND THIS MAY REQUIRE HEADLINES TO BE
ISSUED TODAY IN OUR SOUTH. MODERATE SNOW ACCUMULATIONS OVER 3 INCHES
SEEM LIKELY WITH THIS SYSTEM...AND SHOULD A DIRECT HIT FROM THE DEF
ZONE OCCUR...HEAVY AMOUNTS ARE POSSIBLE. AS THE SYSTEM MOVES PAST
INTO THE LOWER GREAT LAKES...MORE ENERGY IS FORECAST BY THE GFS AND
ECMWF TO MOVE INTO THE WESTERN SIDE OF THE UPPER LOW...AND THIS
SHOULD PRODUCE AN EXTENDED PERIOD OF LIGHT SNOW BEGINNING TUESDAY
NIGHT INTO WEDNESDAY NIGHT. THE GFS IS MOST BULLISH...WITH 1 TO 2
INCHES OF SNOW FOR SEVERAL PERIODS IN A ROW FOR A LARGE AREA...WHILE
THE ECMWF IS MORE CONSERVATIVE. ANY WAY YOU SHAKE IT...IT APPEARS
UNSETTLED...CLOUDY...WITH LIGHT SNOW OR FLURRIES IN THE WAKE OF THE
EARLY WEEK STORM...AT LEAST THROUGH WEDNESDAY NIGHT.
LATE WEEK...MODELS SHOW A MUDDLED MESS OF NORTHERLY FLOW ALOFT.
THERE CERTAINLY COULD BE SOME SNOW POTENTIAL THERE...BUT IF IT WOULD
OCCUR...MOISTURE WOULD BE VERY LIMITED...AND AMOUNTS VERY LIGHT.
TEMPERATURES WILL AGAIN BE FORECAST TO AVERAGE BELOW NORMAL ON
HIGHS...MAINLY IN THE LOWER TO MID 30S THIS WEEK. LOWS IN THE TEENS
TO MID 20S ARE FORECAST FROM NORTHWEST TO SOUTHEAST...WITH THE
MILDEST LOWS ASSOCIATED WITH MONDAY NIGHT AND TUESDAY NIGHT AS WE
SHOULD EXPERIENCE HIGHER DEWPOINTS WITH THE POTENTIAL SNOW EVENT.
ERVIN
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1142 AM CST SAT FEB 23 2013
MVFR CIGS GRADUALLY CLEARING THE TERMINALS FROM WEST TO EAST...AND
SHOULD CLEAR NO LATER THAN 19Z. KDBQ WILL REMAIN NEAR THE EDGE
AND MAY FLIRT WITH BKN015 FOR THE NEXT SEVERAL HOURS...AND WILL
HAVE TO CLOSELY MONITOR. THESE CLEAR SKIES TO ALLOW FOG AND STRATUS TO
DEVELOP LATE TONIGHT AS WARM AIR BEGINS TO ADVECT OVER THE TOP OF
THIS FRESH SNOW. HAVE GONE WITH MAINLY IFR CONDITIONS GENERALLY
FROM 09Z TO 15Z...THOUGH LIFR IS POSSIBLE AT KCID WHERE IT WILL BE
CLEAR THE LONGEST. VISIBILITIES TO REMAIN MVFR AT KDBQ AND KMLI
AS EXPECT STRATUS TO SET IN FIRST. LE
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...LE
SYNOPSIS...08
SHORT TERM...08
LONG TERM...ERVIN
AVIATION...LE
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1142 AM CST SAT FEB 23 2013
.SYNOPSIS...
ISSUED AT 519 AM CST SAT FEB 23 2013
06Z SFC ANALYSIS HAS AN OCCLUDED LOW NEARING THE MACKINAC STRAITS
WHILE HIGH PRESSURE WAS ACROSS THE PLAINS. DEW POINTS WERE IN THE
SINGLE DIGITS AND TEENS ACROSS THE PLAINS WITH 20S AND 30S ACROSS
THE GREAT LAKES AND OHIO VALLEY.
&&
.SHORT TERM...TODAY AND TONIGHT
ISSUED AT 519 AM CST SAT FEB 23 2013
A COMBINATION OF CYCLONIC FLOW ALOFT AND VORT MAXES...MAINLY AT 700
MB IS PRODUCING FLURRIES/LIGHT SNOW ACROSS THE NORTHERN PART OF THE
CWFA AND UP INTO MINNESOTA. THE RAP TRENDS HAVE THE 700MB SHORTWAVE
ROTATING THROUGH DURING THE DAY WITH NEAR CONTINUOUS 700MB VORT
MAXES ROTATING THROUGH. THUS FLURRIES/VERY LIGHT SNOW WILL BE SEEN
ACROSS ROUGHLY THE NORTHERN HALF DURING THE MORNING.
FCST SOUNDINGS SHOW A DRYING ALOFT OCCURRING DURING THE AFTERNOON SO
ANY FLURRIES/LIGHT SNOW WILL GRADUALLY END.
BASED ON 0.5KM CONDENSATION PRESSURES/WIND...CLOUDS SHOULD STAY PUT
FOR MUCH OF THE MORNING BEFORE CLEARING STARTS FROM WEST TO EAST
DURING THE AFTERNOON. THE COLD POOL ALOFT MAY HELP GENERATE SOME
DIURNAL CLOUDS WHICH MAY SLOW THE RATE OF CLEARING DURING THE
AFTERNOON HOURS. ..08..
.LONG TERM...SUNDAY THROUGH NEXT FRIDAY
ISSUED AT 519 AM CST SAT FEB 23 2013
THE EXTENDED STORM IS IN MUCH BETTER AGREEMENT IN MODEL FORECASTS
TONIGHT...AND IS FOCUSED ON A SURFACE LOW TRACK FROM OK/AR THROUGH
INDIANA MONDAY INTO TUESDAY. THE STORM SHOULD ONCE AGAIN HAVE A
BROAD UPPER LOW ASSOCIATED WITH IT...AND BY IN LARGE...THE UPPER LOW
SHOULD DOMINATE THE AREAL PLACEMENT OF RAIN AND SNOW. THE BIGGEST
DIFFERENCE IN MODELS TONIGHT...IS THAT NO MODEL FORECASTS AN
INTENSIFYING SURFACE LOW...OR EVEN A STRONG OCCLUDED LOW AS IT MOVES
PAST THE REGION. THIS WOULD INDICATE A MUCH LOWER RISK FOR A STRONG
WIND DRIVEN SNOW/BLIZZARD THAN THE EARLIER 12Z ECMWF WOULD HAVE
INDICATED. DESPITE THIS...THE STORM SHOULD BE ABLE TO PRODUCE A
HEALTHY DEFORMATION ZONE...AND ALL MODELS BRUSH THIS FORCING THROUGH
THE CENTRAL AND SOUTHERN CWA...AND THIS MAY REQUIRE HEADLINES TO BE
ISSUED TODAY IN OUR SOUTH. MODERATE SNOW ACCUMULATIONS OVER 3 INCHES
SEEM LIKELY WITH THIS SYSTEM...AND SHOULD A DIRECT HIT FROM THE DEF
ZONE OCCUR...HEAVY AMOUNTS ARE POSSIBLE. AS THE SYSTEM MOVES PAST
INTO THE LOWER GREAT LAKES...MORE ENERGY IS FORECAST BY THE GFS AND
ECMWF TO MOVE INTO THE WESTERN SIDE OF THE UPPER LOW...AND THIS
SHOULD PRODUCE AN EXTENDED PERIOD OF LIGHT SNOW BEGINNING TUESDAY
NIGHT INTO WEDNESDAY NIGHT. THE GFS IS MOST BULLISH...WITH 1 TO 2
INCHES OF SNOW FOR SEVERAL PERIODS IN A ROW FOR A LARGE AREA...WHILE
THE ECMWF IS MORE CONSERVATIVE. ANY WAY YOU SHAKE IT...IT APPEARS
UNSETTLED...CLOUDY...WITH LIGHT SNOW OR FLURRIES IN THE WAKE OF THE
EARLY WEEK STORM...AT LEAST THROUGH WEDNESDAY NIGHT.
LATE WEEK...MODELS SHOW A MUDDLED MESS OF NORTHERLY FLOW ALOFT.
THERE CERTAINLY COULD BE SOME SNOW POTENTIAL THERE...BUT IF IT WOULD
OCCUR...MOISTURE WOULD BE VERY LIMITED...AND AMOUNTS VERY LIGHT.
TEMPERATURES WILL AGAIN BE FORECAST TO AVERAGE BELOW NORMAL ON
HIGHS...MAINLY IN THE LOWER TO MID 30S THIS WEEK. LOWS IN THE TEENS
TO MID 20S ARE FORECAST FROM NORTHWEST TO SOUTHEAST...WITH THE
MILDEST LOWS ASSOCIATED WITH MONDAY NIGHT AND TUESDAY NIGHT AS WE
SHOULD EXPERIENCE HIGHER DEWPOINTS WITH THE POTENTIAL SNOW EVENT.
ERVIN
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1142 AM CST SAT FEB 23 2013
MVFR CIGS GRADUALLY CLEARING THE TERMINALS FROM WEST TO EAST...AND
SHOULD CLEAR NO LATER THAN 19Z. KDBQ WILL REMAIN NEAR THE EDGE
AND MAY FLIRT WITH BKN015 FOR THE NEXT SEVERAL HOURS...AND WILL
HAVE TO CLOSELY MONITOR. THESE CLEAR SKIES TO ALLOW FOG AND STRATUS TO
DEVELOP LATE TONIGHT AS WARM AIR BEGINS TO ADVECT OVER THE TOP OF
THIS FRESH SNOW. HAVE GONE WITH MAINLY IFR CONDITIONS GENERALLY
FROM 09Z TO 15Z...THOUGH LIFR IS POSSIBLE AT KCID WHERE IT WILL BE
CLEAR THE LONGEST. VISIBILITIES TO REMAIN MVFR AT KDBQ AND KMLI
AS EXPECT STRATUS TO SET IN FIRST. LE
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...08
SHORT TERM...08
LONG TERM...ERVIN
AVIATION...LE
AREA FORECAST DISCUSSION...UPDATED
NWS BILLINGS MT
938 AM MST SAT FEB 23 2013
.SHORT TERM...VALID FOR TDY AND SUN...
AREA OF SNOW THIS MORNING OVER THE WESTERN ZONES WITH SOME SNOW
SHOWERS EAST OF BILLINGS BUT RADAR SEEMS TO BE REFLECTING MORE
MELTING LAYER ACTIVITY THAN ACTUAL SNOWFALL. SNOWFALL LOOKS TO BE
INTENSE FOR ABOUT A HALF HOUR BEFORE DECREASING...SO UPDATED
CURRENT FORECAST TO NUDGE UP AMOUNTS OVER THE SOUTHWESTERN ZONES A
BIT. SNOWFALL SHOULD BECOME A BIT MORE PERSISTENT SOUTH OF
BILLINGS THIS AFTERNOON AS DIGGING SYSTEM OVER IDAHO CAUSES A
FRONTAL BOUNDARY TO BEGIN SLOWING. FRONT SHOULD REACH BILLINGS
AROUND NOON BUT STILL COULD SEE A COUPLE OF DEGREES OF WARMING
BETWEEN NOW AND THEN SO DID NOT LOWER TEMPERATURES. MOST
PRECIPITATION WILL FALL AS SNOW ESPECIALLY WITH DEWPOINT
DEPRESSIONS AROUND 20 DEGREES...BUT RADAR DOES INDICATE SOME
MELTING MAY BE GOING ON. UPDATE SENT. BORSUM
PREVIOUS DISCUSSION...ISSUED AT 308 AM MST SAT FEB 23 2013...
PASSAGE OF A 500-HPA SHORT WAVE TROUGH AND SURFACE COLD FRONT WILL
BRING SNOW SHOWER CHANCES TO THE FOREFRONT TODAY. MOISTURE CHANNEL
IMAGERY AT 10 UTC SHOWS THAT TROUGH AXIS ENTERING WESTERN ID...AND
THAT IS STARTING TO DISRUPT THE ENVIRONMENT NEEDED FOR NOTABLE GAP
WINDS. THAT PROCESS SHOULD BE COMPLETE BETWEEN 12 AND 15 UTC...BUT
IN THE INTERIM WE WILL LET OUR WIND ADVISORY AT LIVINGSTON AND NYE
RIDE FOR A FEW MORE HOURS.
TODAY AND TONIGHT...WE HAVE POPS IN THE 60 TO 90 PERCENT RANGE FOR
1/ THE LIVINGSTON...BIG TIMBER...AND COOKE CITY AREAS UNTIL 18 UTC
AND 2/ THE LODGE GRASS...SHERIDAN...AND EVEN BROADUS AREAS BETWEEN
18 AND 06 UTC. THOSE LIKELY AND CATEGORICAL POPS ARE LINED UP WITH
THE MOST GENEROUS SYNOPTIC-SCALE FORCING WITH THE SHORT WAVE ALOFT
AND THE EXIT REGION OF A WEAKENING 300-HPA JET STREAK WHICH THE 00
UTC GUIDANCE SHOWS SINKING SOUTHWARD TODAY. WE HAVE CHANCE POPS IN
MOST OTHER PLACES DURING THE DAY...INCLUDING BILLINGS...BUT DIDN/T
GO ANY HIGHER IN ORDER TO CONVEY THE MORE SCATTERED OR SHORT-LIVED
NATURE OF SHOWERS OUTSIDE OF THE BETTER FORCING. SNOW IS MENTIONED
AS THE PREDOMINATE PRECIPITATION TYPE FOR MOST OF THE AREA BECAUSE
THAT NOTION HAS STRONG SUPPORT FROM GFS/ECMWF/NAM WET BULB HEIGHTS
AND NCEP PRECIPITATION-TYPE ALGORITHMS APPLIED TO THE 21 UTC SREF.
WHERE IMPACTS ARE CONCERNED...OUR MAIN CONCERN IS FOR SHERIDAN AND
MAYBE EVEN SOUTHERN BIG HORN COUNTY...WHERE THERE IS SOME RISK OF
ADVISORY-LEVEL SNOWFALL THIS AFTERNOON AND EVENING. THE 00 UTC GFS
AND RECENT RUNS OF THE RAP /WHICH GETS LATERAL BOUNDARY CONDITIONS
FROM THE GFS/ ARE THE MOST AGGRESSIVE QPF SOLUTIONS FOR THAT AREA.
HOWEVER...SINCE THOSE QPF NUMBERS ARE HIGHER THAN MOST OF THE REST
OF THE PACK...AND BECAUSE IT IS NOT CLEAR HOW EFFICIENT UPSLOPE IN
THE LOW LEVELS WILL BE...WE CHOSE TO KEEP SNOW AMOUNTS IN THE 1 TO
3 INCH RANGE /JUST BELOW ADVISORY CRITERIA/ FOR NOW. THIS COULD BE
A CASE WHERE NEAR TERM OBSERVATIONAL TRENDS GIVE ENOUGH CONFIDENCE
FOR US TO HOIST A HEADLINE LATER TODAY IF GFS-BASED SOLUTIONS WIND
UP BEING CORRECT. THE 06 UTC GFS HAS TRENDED EVEN HIGHER WITH ITS
QPF...SO THIS SITUATION BEARS CLOSE WATCHING.
SUN...NORTH-NORTHWEST FLOW WILL BE IN PLACE ALOFT WITH BOTH MODEST
DRYING AND WARMING IN THE LOW- AND MID-LEVELS. WE DECIDED TO LEAVE
OUR GOING FORECAST ALONE FOR NOW SINCE IT SHOWS POPS MAINLY BEFORE
18 UTC...WHEN FLOW IS MORE CYCLONIC. HOWEVER...BOTH THE 00 UTC GFS
AND NAM SHOW A DECENT BATCH OF 500-300 HPA Q-VECTOR CONVERGENCE IN
THE 18 TO 00 UTC TIME FRAME...WHICH MAKES US WONDER IF THERE COULD
BE SOME CONVECTION DURING THE AFTERNOON. THAT WILL BE SOMETHING TO
CONSIDER WITH LATER FORECAST RELEASES. OTHERWISE...WE DID INCREASE
HIGHS USING THE 00 UTC BIAS-CORRECTED MULTI-MODEL CONSENSUS /WHICH
HAS VERIFIED WELL LATELY/...AND WINDS ON SUN NIGHT NEAR LIVINGSTON
AND BIG TIMBER AS SURFACE PRESSURE FALLS BEGIN ACROSS THE NORTHERN
ROCKIES AGAIN. SCHULTZ
.LONG TERM...VALID FOR MON...TUE...WED...THU...FRI...
MODELS IN PRETTY GOOD AGREEMENT THROUGH WEDNESDAY. SMALL SYSTEM
FOR THURSDAY SHOWS SOME SIGNS OF GETTING BETTER ORGANIZED IN THE
GFS BUT NOT SO MUCH IN THE EUROPEAN MODEL. STRONG RIDGING AND MUCH
WARMER TEMPERATURES LOOK TO BE ON TRACK FOR NEXT WEEKEND.
BRIEF RIDGING BEHIND SUNDAY SYSTEM SHOULD BRING PARTLY CLOUDY AND
DRY CONDITIONS TO THE FIRST HALF OF MONDAY. BY LATE IN THE DAY
NEXT SYSTEM UPSTREAM QUICKLY BUILDS INTO THE AREA WITH INCREASING
PRECIPITATION CHANCES THROUGH TUESDAY. SOME WEAK ENERGY LINGERS
INTO WEDNESDAY OVER SOUTHERN ZONES BUT BY WEDNESDAY AFTERNOON
RIDGING DEVELOPS ENDING PRECIPITATION CHANCES.
GFS BRINGS NEXT SYSTEM INTO IDAHO WEDNESDAY NIGHT AND SEEMS TO BE
TRYING TO CUT OFF UPPER LOW NEAR WEST YELLOWSTONE THURSDAY
MORNING. ECMWF DIGS THIS SAME TROF MUCH FURTHER SOUTH AND SPLITS
THE SYSTEM OVER THE AREA RESULTING IN SOME CLOUD COVER BUT LITTLE
IN THE WAY OF PRECIPITATION OUTSIDE OF MOUNTAIN AREAS. CAUSE OF
THE DIFFERENCES IS DUE TO HANDLING OF STRONG DOWNSTREAM SYSTEM
OVER THE EASTERN US...AND CURRENT GUIDANCE FAVORS THE EC SOLUTION
SO LEFT FORECAST DRY AND WARMED TEMPERATURES JUST A BIT.
ALL THE MODELS IN GOOD AGREEMENT WITH DEVELOPMENT OF STRONG
RIDGING FRIDAY THROUGH NEXT WEEKEND. BOTH MODELS SHOW SATURDAY 850
TEMPERATURES IN THE +6 TO +10C RANGE LEADING TO MIX DOWN
TEMPERATURES WELL INTO THE 50S FOR HIGHS FRIDAY THROUGH SUNDAY.
NOT OUT OF THE QUESTION TO SEE SOME LOWER 60S SATURDAY AND SUNDAY
WITH DRY CONDITIONS UNDER THE RIDGE. CHAMBERS
&&
.AVIATION...
SCATTERED SNOW SHOWERS ARE DEVELOPING ACROSS THE AREA AS THE COLD
FRONT MOVES THROUGH. MAINLY VFR CONDITIONS WILL PREVAIL IN MOST
AREAS WITH LOWER CONDITIONS IN AND AROUND NEAR SNOW SHOWERS.
VLIFR CONDITIONS HAVE BEEN REPORTED IN KLVM THIS MORNING...WITH
LOW CIGS AND VIS. FOOTHILLS AND MOUNTAIN AREAS WILL SEE MAINLY
MVFR CONDITIONS WITH LOCAL IFR OR LOWER CONDITIONS WITH HEAVIER
SNOW SHOWERS. MOUNTAIN AND PASS OBSCURATION WILL EXIST FOR ALL
AREA MOUNTAINS THROUGH TONIGHT. AAG
&&
.PRELIMINARY POINT TEMP/POPS...
TDY SUN MON TUE WED THU FRI
-------------------------------------------------------
BIL 041 025/041 022/039 024/037 021/037 023/045 026/051
4/W 32/J 11/B 33/J 11/U 32/J 00/B
LVM 039 020/035 016/035 019/032 013/033 017/038 025/044
8/W 33/W 12/J 44/J 11/U 32/J 11/B
HDN 042 023/043 019/037 022/036 017/035 020/043 023/049
5/W 43/J 11/B 34/J 21/U 33/J 10/B
MLS 044 027/042 021/037 022/036 020/035 020/041 024/047
2/W 22/J 11/U 23/J 21/B 12/J 10/B
4BQ 041 024/038 017/035 020/033 018/032 017/039 020/045
6/W 73/J 11/U 24/J 21/B 12/J 10/B
BHK 041 024/035 016/032 019/031 018/031 016/036 018/040
3/W 22/J 11/U 13/J 21/B 11/B 10/B
SHR 038 020/036 012/034 018/032 015/033 016/039 018/045
8/J 83/J 11/U 44/J 21/U 22/J 10/B
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1252 PM EST SAT FEB 23 2013
.SYNOPSIS...
A COMBINATION OF TWO STORM SYSTEMS...ONE TO OUR NORTHWEST AND
ANOTHER MOVING UP THE COAST...WILL BRING US UNSETTLED WEATHER
TODAY WITH PLENTY OF CLOUDS. MOST OF THE AREA WILL SEE RAIN
DEVELOP BY AFTERNOON...BUT SOME WET SNOW IS POSSIBLE ACROSS ONEIDA
COUNTY AND THE CATSKILLS. BY TONIGHT AS COLDER AIR MOVES BACK INTO
OUR AREA...A PERIOD OF FREEZING RAIN IS POSSIBLE OVER THE
CATSKILLS...WITH A GRADUAL TRANSITION FROM RAIN TO SNOW OVER THE
ENTIRE AREA BEFORE ENDING. LIGHT SNOW SHOWERS ARE POSSIBLE SUNDAY
IN CENTRAL NY WITH DRIER WEATHER BY MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
930 AM UPDATE...
CONVOLUTED FCST WITH CWA RMNG IN VRY WK FORCING AND PCPN POPPING
UP AT RANDOM ACRS THE AREA, THO MOST IS CONFINED CLOSER TO H5-H7
LIFT IN THE FINGER LKS REGION. 12Z RAOBS FM KBUF AND KALY SHOWING
VRY LITTLE ICE IN THE CLD, IN AGREEMENT WITH FCST SNDGS FM BUFKIT.
MOST OBS ACRS THE AREA ARE REPORTING SOME FORM OF LIQUID THUS HV
TWEAKED WX GRIDS TO GO RAIN OR DRIZZLE EXCEPT WHERE LOCALES ARE
BLO FZG AND HV ADDED IN A FRZG MENTION. MOISTURE RETURNS IN THE
-10C TO -20C LAYER AFTR ABOUT 18Z THIS AFTN AND HV ADDED IN
SNOW/FLURRY MENTION BACK IN.
BEST CHC FOR SNOW LOOKS TO BE ACRS NRN ONEIDA CNTY LATE THIS AFTN
WITH STRONG CONVERGENCE BRINGING A QUICK 1-2 INCHES LATE TDA.
ELSEWHERE IT LOOKS TO BE A WINTRY MESS FOR MOST OF THE DAY.
LATEST NAM12 HAS COME IN WITH CURRENT SFC LOW LOCATED OFF OF VA/NC
BORDER RMNG SOUTH OF OUR AREA TONIGHT AND VRY MINIMAL QPF
SPREADING INTO SERN PARTS OF CWA THRU TONIGHT. ONSHORE FLOW WL BE
POSSIBLE WITH CHC CONTG FOR LGT PCPN BUT WL IT BE IN THE FORM OF
LGT FZRA OR FZDZ. WL AWAIT ADDNL 12Z GUIDANCE BFR MAKING DECISION
ON WHAT TO DO WITH EXISTING ADVISORY FOR TONIGHT, WHETHER IT BE TO
TWEAK THE AREA OR CANCEL IT ALTOGETHER.
ONLY MINOR TWEAKS MADE TO HRLY T/TD GRIDS AT THIS TIME.
6 AM UPDATE...
THIS MORNING...AN AREA OF PRECIPITATION MAINLY FROM THE NY/PA LINE
NORTH THROUGH THE FINGER LAKES CONTINUES TO MOVE THROUGH OUR AREA.
OVER THE PAST 2 HOURS THE INTENSITY ON RADAR OF THIS PRECIP HAS
INCREASED. THIS IS LIKELY DUE TO SOME SLEET MIXING IN AS EVIDENT
BY LOWER VALUES OF CC ON THE DUAL POL PRODUCTS. THIS IS INDICATING
MIXED HYDROMETEORS AND BASED ON SOUNDINGS AND THIS AREA COINCIDING
WITH HIGHER RETURNS...SLEET IS THE MOST LIKELY P-TYPE HERE. THE
LATEST RUC SEEMS TO OFFER THE BEST HOPE FOR A SHORT TERM FORECAST
BASED ON A LOBE OF VORTICITY AT 500 MB MOVING THROUGH...THAT LINES
UP WELL WITH THE PRECIP. THE RUC MOVES THIS OFF TO THE NORTHEAST
BY 12Z. BASED ON RADAR TRENDS THOUGH MAY SLOW THIS DOWN A TAD.
PRECIP INTENSITY WILL BE RELATIVELY LIGHT AS WILL QPF AMOUNTS. WE
ARE LACKING ICE IN THE CLOUD SO P-TYPE LOOKS TO BE MAINLY RAIN OR
SOME ICE PELLETS EXCEPT ACROSS THE FAR NORTH AND EAST WHERE
SLIGHTLY DEEPER MOISTURE PROFILES ALLOW FOR SOME SNOW. ISOLATED
POCKETS OF FREEZING RAIN ARE POSSIBLE BUT IT APPEARS WHERE THE
LIQUID PRECIP IS MOST LIKELY...TEMPS ARE ALREADY NEAR OR ABOVE
FREEZING. WHERE WE HAVE COLDER SURFACE TEMPS...MOISTURE ALOFT
SUPPORTS MORE SNOW. AFTER THIS MOVES THROUGH WE MAY SEE A LULL FOR
A FEW HOURS FOR MOST OF US.
LATER THIS MORNING/TONIGHT...NEXT FEATURES OF INTEREST WILL BE AN
AREA OF LOW PRESSURE MOVING THROUGH THE GREAT LAKES AND AN AREA OF
LOW PRESSURE NOW TAKING SHAPE OFF THE CAROLINA COAST. OUR AREA
WILL BE IN ON THE SQUEEZE PLAY TODAY WITH INCREASING MOISTURE FROM
BOTH THE WEST (GREAT LAKES SYSTEM) AND EAST (COASTAL SYSTEM). MAIN
ADJUSTMENT WAS TO TRIM BACK POPS IN THE MIDDLE TODAY...AND PUSH
BACK THE BEST SHOT AT WIDESPREAD PRECIPITATION INTO THE 18Z - 22Z
RANGE. OVERALL THOUGH LOOKING AT A FAIRLY LIGHT QPF EVENT WITH
AROUND AMOUNTS RANGING FROM A TENTH TO TWO TENTHS. THE FIRST
TRIGGER FOR PRECIP WILL COME BY LATE MORNING AS A RIBBON OF PVA
SLIDES INTO WESTERN NY...IN THE FLOW AROUND THE PARENT UPPER LOW
OVER THE GREAT LAKES. THIS WILL MOVE ACROSS THE REST OF THE AREA
TOWARD 20Z...AS WE ALSO GETTING INCREASING UPPER LEVEL LIFT OVER
THE FAR SOUTHEAST IN RESPONSE TO THE COASTAL LOW. I RAMP POPS UP
GREATLY IN THE 22Z TO 0Z PERIOD TO SHOW OUR BEST SHOT AT
PRECIPITATION ACROSS MOST OF THE AREA AS THIS HAPPENS.
AS FAR AS P-TYPE GOES...A TONGUE OF WARMER AIR AROUND 800 MB WILL
KEEP US MOSTLY RAIN THROUGH LATE THIS AFTERNOON. THE EXCEPTION
WILL BE ACROSS NORTHERN ONEIDA COUNTY WHERE TEMPS ALOFT NEVER GET
ABOVE 0C...SO AT THE VERY LEAST A RAIN/SNOW MIX IS LIKELY IF NOT
MOSTLY SNOW...ALL DAY. WE COULD SEE UP TO 2 INCHES HERE THROUGH
AFTERNOON ACROSS THE HIGHER TERRAIN. OVER THE FAR EAST SNOW IS
POSSIBLE EARLY BUT EVEN HERE TEMPS ALOFT WARM UP ABOVE 0C AFTER
21Z. DURING THIS TIME SOME AREAS OF FREEZING RAIN ARE POSSIBLE IN
OUR NORMALLY COLDEST SECTIONS...WITH PLAIN RAIN OR A FEW SLEET
PELLETS POSSIBLE ELSEWHERE.
TONIGHT...AS THE COASTAL SYSTEM DEEPENS AND MOVES WELL OUT TO
SEA...COLDER AIR ALOFT WILL RAPIDLY MOVE IN FROM THE WEST. THIS
WILL CHANGE OUR RAIN OVER TO A PERIOD OF LIGHT SNOW BEFORE ENDING
OVERNIGHT. ACCUMS EXPECTED TO BE AROUND AN INCH OR LESS. THE
TRICKY SPOT WILL BE ROUGHLY FROM DELAWARE COUNTY SOUTH THROUGH
WAYNE AND PIKE COUNTIES...WHERE TEMPS ALOFT WILL REMAIN ABOVE 0C
THROUGH 03Z THIS EVENING. NAM SOUNDINGS HAVE REMAINED CONSISTENT
SINCE LAST NIGHT SHOWING SOME BOUNDARY LAYER COOLING DURING THIS
TIME ALLOWING SURFACE TEMPS TO BE NEAR OR SLIGHTLY BELOW FREEZING.
GFS PROFILES COULD NOT BE MORE DIFFERENT WITH TEMPS REMAINING
ABOVE FREEZING AT THE SURFACE...BEFORE A RAPID TRANSITION FROM
RAIN TO SNOW...WITH NO PERIOD OF FREEZING RAIN. SREF PROFILES
PROVIDE LITTLE HELP WITH SOLUTIONS SHOWING A WILD RANGE. BASED ON
CLIMATOLOGY...COORDINATION WITH SURROUNDING WFOS...AND BUYING THAT
THE HIGHER RESOLUTION OF THE NAM THIS CLOSE IN SHOULD BE SUPERIOR TO
THE GFS...ISSUED A WINTER WEATHER ADVISORY FOR THESE AREAS. WE WANT
TO STRESS THIS ADVISORY IS NOT FOR THE SNOWFALL AMOUNTS BUT FOR
THE SHORT WINDOW OF TIME FROM BETWEEN 22Z THROUGH 03Z WHEN WARM
TEMPS ALOFT COMBINED WITH COOLING SURFACE TEMPS WILL ALLOW FOR A
PERIOD OF FREEZING RAIN. LATE TONIGHT WE HAVE PLENTY OF MOISTURE
IN THE LOW LEVELS BY LACK OF MOISTURE IN THE MID LEVELS (NO ICE
CRYSTALS) WILL LIKELY MEAN A FAIRLY RAPID END FROM WEST TO EAST OF
ANY PRECIP.
&&
.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
600 AM UPDATE...
SUNDAY/SUNDAY NIGHT...NOT MUCH CHANGE TO THE PREVIOUS FORECAST.
WE REMAIN UNDER THE INFLUENCE OF THE UPPER LEVEL LOW WITH CHANCES
FOR LIGHT SNOW MAINLY IN CNY BY SUNDAY AFTERNOON/NIGHT. NOT
LOOKING FOR MUCH IN TERMS OF ACCUMS.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AN UNSETTLED PTRN FOR THE MED RNG AS LARGE UPR LVL LOW...WITH SVRL
EMBEDDED IMPULSES ROTATING ARND IT...TAKES UP RESIDENCE OVER THE
NE U.S.. ALL IN ALL THE HPC GDNC LOOKED GOOD BUT CHC POPS LOOKED A
BIT ON THE LOW SIDE GIVEN THIS PTRN...SPCLY OVER CNTRL NY WHERE
MOIST SYNOPTIC AIRMASS AND CYCLONIC FLOW WILL COMBINE WITH LAKE
INFLUENCES TO ENHANCE THE SNOW SHOWERS. THIS FAR OUT...WE OPTED TO
RAISE HPC CHC POP NUMBERS LATE IN THE PD AND USED "SCATTERED"
TERMINOLOGY THROUGHOUT. IF MDLS REMAIN CONSISTENT...NO DOUBT
WE`LL BE RAISING THE MED RNG POPS TO LIKELY FOR MUCH OF THE
RGN...BUT PLENTY OF TIME FOR THAT THIS FAR OUT. PLUS WE KNOW ALL
THE SUPRISES THESE CUTOFFS CAN THROW AT US. TEMPS WILL GNRLY RNG
FROM THE MAXES IN THE M30S TO MINS IN THE U20S.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
WDSPRD IFR/MVFR WILL PREVAIL FOR THE REMAINDER OF THE AFTN AND
OVRNGT HRS...WITH CONDITIONS LIKELY TO BE BLO AIRPORT MINS AT
TIMES (SPCLY AT BGM/ITH/ELM/AVP). ANY PCPN WILL BE ON THE LGT
SIDE...AND PROFILES SUGGEST SHRA OR A MIX TRANSITIONING TO -SHSN
TNGT AS SLIGHTLY COLDER AIR MOVS IN. XPCT MVFR TO CONTINUE AT MOST
SITES INTO SUN MRNG. WINDS THIS AFTN GNRLY FROM THE SOUTH 5-10
KT...THEN VRBL BECMG WNW LATER TNGT 5-10 KTS...THEN W TO NW ON SUNDAY
INCRSNG TO 10-20 KTS.
.OUTLOOK...
SUN NGT/MON...PATCHY MVFR CIGS CNTRL NY...OTRW VFR.
MON NGT...VFR.
TUE...VFR EARLY DETERIORATING TO MVFR/IFR IN MIXED PCPN.
TUE NGT/WED/THU...IFR/MVFR IN SNOW AND RAIN SHOWERS.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 7 AM EST
SUNDAY FOR PAZ040-048-072.
NY...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 7 AM EST
SUNDAY FOR NYZ057-062.
&&
$$
SYNOPSIS...HEDEN
NEAR TERM...HEDEN/PVN
SHORT TERM...HEDEN
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
1025 AM CST SAT FEB 23 2013
.DISCUSSION...
CLOUDS AND TEMPS ARE THE MAIN CHALLENGE FOR TODAYS FORECAST.
PRETTY CONSISTENT CLOUD BAND JUST TO THE EAST OF THE RED RIVER
VALLEY WITH LOTS OF SUN TO THE WEST. THERE ARE ALSO SOME HOLES IN
THE CLOUDS DOWN NEAR KAXN AND UP BY KINL. SFC FEATURES ARE EVIDENT
ON THE VISIBLE SATELLITE IMAGERY THROUGH THE CLOUDS EAST OF THE
VALLEY. HOWEVER THERE IS VERY WEAK WIND FLOW SO THE MAIN QUESTION
WILL BE THE POWER OF THE LATE FEBRUARY SUN. THERE ARE SOME HINTS
OF EROSION ON THE WESTERN FRINGE OF THE MAIN CLOUD BAND AND WITH
THE HOLES APPEARING ALREADY IN THE PREVIOUSLY MENTIONED AREAS
THINK THERE MAY BE A SHOT AT CLEARING IN THE IMMEDIATE RED RIVER
VALLEY AND FOR THE LAKE OF THE WOODS REGION. OTHER AREAS FROM KDTL
TO KROX MAY BE A TOUGHER CALL AND WILL JUST HAVE TO SEE HOW THINGS
PAN OUT. LOTS OF FOG OUT THERE NOW BUT VSBYS HAVE MOSTLY RISEN
ENOUGH TO LEAVE ANY MENTION OF IT OUT FOR THE AFTERNOON.
&&
.AVIATION...
AS WITH THE ABOVE REASONING WILL JUST HAVE TO MONITOR THE TAF
SITES THRU THE REST OF THE MORNING TO SEE IF ANY TRENDS CAN BE
ESTABLISHED.
&&
.PREV DISCUSSION... /ISSUED 326 AM CST SAT FEB 23 2013/
SHORT TERM (TODAY-MONDAY NIGHT)...
INITIALLY CLOUDS AND FOG WILL BE THE CONCERN. OTHERWISE...CLOUDS
AND LIGHT SNOW CHANCES WILL BE THE CHALLENGE. 00Z MODELS IN
DECENT AGREEMENT ALTHOUGH WITH DETAIL DIFFERENCES SUNDAY INTO
MONDAY. WILL USE A BLEND FOR THIS FORECAST.
THE FORECAST AREA (FA) IS CURRENTLY STUCK WITHIN A VERY WEAK FLOW
ENVIRONMENT. LOW CLOUDS EXIST ALONG AND EAST OF THE VALLEY. THESE
CLOUDS SEEM TO BE OCCURRING WHERE MODELS SHOW 925MB WINDS CALM TO
5 KNOTS. WILL USE THE RAP AS GUIDANCE FOR WHEN SKIES WILL CLEAR
FROM WEST TO EAST (AS LOW LEVEL FLOW INCREASES). THIS SLOWS THE
CLEARING TREND TODAY. PATCHY DENSE FOG HAS OCCURRED WITHIN THIS
WEAK FLOW ENVIRONMENT...BUT 1/4SM VSBY HAS NOT BEEN CONSISTENT
FROM HOUR TO HOUR. WILL KEEP PATCHY FOG IN THE GRIDS THROUGH THE
MORNING HOURS WHERE CLOUDS (WEAK MIXING) IS EXPECTED...AND MONITOR
FOG CONDITIONS.
FOR SUNDAY INTO MONDAY...SOUTHERN STREAM ENERGY WILL REMAIN WELL
SOUTH OF THE REGION...BUT THERE WILL BE A WEAK NORTHERN STREAM
WAVE THAT AFFECTS THE REGION DURING THIS TIME. THE ECMWF IS
STRONGER WITH THE RIDGING TO THE EAST...AND KEEPS THIS FEATURE
WEST OF OTHER MODELS (WESTERN DAKOTAS VS EASTERN DAKOTAS) AS IT
DROPS TO THE SOUTH AND INTO THE SOUTHERN STREAM WAVE. THE MAIN
AFFECT OF THIS WAVE WILL LIKELY BE CLOUD COVER...BUT LIGHT SNOW
IS ALSO POSSIBLE. THE EXACT LOCATION OF THIS WAVE WILL DETERMINE
WHERE/WHEN THE LIGHT SNOW OCCURS. IF THE ECMWF IS CORRECT
ACCUMULATIONS WILL BE MAYBE A DUSTING...AND IF THE OTHER MODELS
ARE CORRECT ACCUMULATIONS COULD BE AN INCH OR TWO. WILL MAINTAIN
PREVIOUS FORECAST OF LOW POPS ACROSS THE WESTERN FA WITH ONLY A
DUSTING POSSIBLE (AS PMDHMD PREFERS THE ECMWF).
LONG TERM (TUESDAY-FRIDAY)...
MODELS CONTINUE TO BE IN FAIR AGREEMENT WITH A QUIET WEATHER PATTERN
FOR THE CWFA FOR THE EXTENDED TIME FRAME WITH A SPLIT FLOW IN THE
STORM TRACK. 500MB FLOW WILL TRANSITION FROM AN ARKANSAS CUTOFF LOW
WITH THE NWERLY ORIENTED TROUGH THROUGH THE NORTHERN US ROCKIES INTO
A POSITIVE PNA PATTERN...WESTERN RIDGE AND EASTERN TROUGH ACROSS THE
CONUS...BY THE END OF THE PERIOD. WITH LITTLE UPPER LEVEL ENERGY
MOVING ACROSS THE AREA ONLY SLIGHT CHC FOR POPS WITH -SN POSSIBLE
TUE AND WED ACROSS THE SOUTH AND EAST ZONES WITH TEMPS NEAR END OF
FEB NORMALS.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
GODON
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
255 PM CST SAT FEB 23 2013
.SHORT TERM...TONIGHT THROUGH TUESDAY
255 PM CST SAT FEB 23 2013
MAIN FORECAST CONCERNS ARE ON FREEZING FOG POTENTIAL TONIGHT AND IF
AND WHEN SNOW CAN MOVE IN FOR EARLY NEXT WEEK.
CURRENTLY AS OF 21Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT
ANALYSIS SHOWED TROUGHING DIGGING DOWN THROUGH THE U.S. ROCKIES...
RIDGING BUILDING HEAD OF THIS TROUGH INTO THE CENTRAL PLAINS AND
AN UPPER LOW ENCOMPASSING MUCH OF THE WESTERN GREAT LAKES REGION.
THIS UPPER LOW COMBINED WITH MOISTURE AND WEAK SHORTWAVES ROTATING
AROUND IT HAS KEPT CLOUDS IN PLACE ACROSS THE NORTHWEST HALF OF
THE FORECAST AREA. 12Z GRB AND MPX SOUNDINGS REFLECT THE
MOISTURE...TRAPPED BELOW A SUBSIDENCE INVERSION BETWEEN 750-800MB.
THERE WERE SOME SNOW SHOWERS/FLURRIES EARLIER...BUT THESE HAVE
SINCE DISSIPATED FOR THE MOST PART. TO THE WEST...CLEARING HAS
BEEN WORKING INTO SOUTHWESTERN PORTIONS OF THE FORECAST AREA FROM
THE PLAINS AND IOWA. 12Z ABR AND OAX SOUNDINGS SHOWED THE DRIER
AIR WITH DEWPOINT DEPRESSIONS OF 5C OR MORE FROM JUST ABOVE THE
SURFACE TO 300MB. AT THE SURFACE WAS A STRONG RADIATIONAL
INVERSION THAT WAS SATURATED...REFLECTING THE FOG THAT OCCURRED.
BOTH LOCATIONS WERE UNDER A RIDGE OF HIGH PRESSURE WHICH HAS
SHIFTED EAST TO CENTRAL PORTIONS OF IOWA AND MINNESOTA. AIRMASS
REMAINS COOL WITH 850MB TEMPS FROM 12Z SOUNDINGS BETWEEN -10C AND
-12C...OR 1 STANDARD DEVIATION BELOW NORMAL.
SHORT TERM HIGHLIGHTS/CONCERNS...
TONIGHT - CLEARING/TEMPS/FOG - MODELS ARE STRUGGLING A BIT WITH THE
CLEARING IMPACTING WESTERN PORTIONS OF THE FORECAST AREA. 925MB RH
FIELDS FROM THE RAP/NAM/GFS WOULD ALL SUGGEST A PESSIMISTIC IDEA
WITH CLOUDS HANGING AROUND MUCH OF THE NIGHT ACROSS THE FORECAST
AREA. HOWEVER...AS NOTED BY SATELLITE IMAGERY...WE HAVE PARTIALLY
CLEARED OUT ALREADY OVER THE SOUTHWEST HALF OF THE AREA. WITH THE
SURFACE RIDGE MOVING OVER THE ENTIRE FORECAST AREA BY 12Z
SUNDAY...THINKING THE CLEARING SHOULD CONTINUE TO PROGRESS EAST. THE
CLEARING SKIES IN THE EVENING COMBINED WITH LIGHT WINDS...DRIER
AIR MOVING IN ALOFT AND THE FRESH SNOW PACK MAKE A GREAT SITUATION
FOR RADIATIONAL COOLING. WENT TOWARDS THE COLDER GFS40 2 METER
TEMPERATURE GUIDANCE FOR LOWS...WHICH WAS FAIRLY SIMILAR TO THE
PREVIOUS FORECAST. THE LOWS...WHICH DROP INTO THE SINGLE DIGITS
ABOVE ZERO SOUTHWEST OF I-94...COMBINED WITH THE CURRENT AFTERNOON
DEWPOINTS IN THE 15 TO 20 RANGE YIELD A FAVORABLE FOG AND VERY LOW
STRATUS SITUATION VIA CROSS-OVER APPROACH. SREF PROBABILITIES OF
LESS THAN 1 MILE SHOW A RAPID DEVELOPMENT AND EXPANSION OF FOG
THROUGH THE EVENING ACROSS MINNESOTA AND IOWA...THEN SPREADING EAST
INTO WISCONSIN. LATEST HRRR RUNS ARE VERY SIMILAR. GIVEN THE
TEMPERATURES...FREEZING FOG WITH RIMING ON UNTREATED SURFACES WOULD
OCCUR. HAVE ADDED THE FOG TO THE FORECAST...WITH THE MOST COVERAGE
WEST AND SOUTH OF I-94 WHERE CONFIDENCE IS HIGHEST. IN ADDITION...
AFTER COLLABORATION FROM SURROUNDING OFFICES...ISSUED A FREEZING FOG
ADVISORY FOR MUCH OF THE FORECAST AREA LINING UP WITH THE GENERAL
MINIMUM IN LOW TEMPS AND CLEARING AREA. IT IS POSSIBLE DENSE FOG
COULD OCCUR AS WELL...BUT CONFIDENCE IS TOO LOW TO GO WITH THAT
ADVISORY TYPE AT THIS TIME. IF DENSE FOG WERE TO OCCUR...ALONG
AND WEST OF HIGHWAY 52 WOULD APPEAR TO HAVE THE BEST CHANCE. LATER
SHIFTS MAY NEED TO REPLACE SOME OF THE FREEZING FOG ADVISORY WITH
DENSE FOG IF CONFIDENCE OF GROWS. ANY FOG/STRATUS MAY TAKE SOME
TIME TO MIX OUT...BUT THE HIGHER LATE FEBRUARY SUN ANGLE SHOULD
ALLOW IT TO CLEAR OUT BY 18Z.
MONDAY THROUGH TUESDAY - WINTER STORM COMING OUT OF THE SOUTHERN
PLAINS - WHAT HAS BEEN CONSISTENT...
1. THE UPPER TROUGH RESPONSIBLE FOR THE STORM...CURRENTLY THE BASE
OF THE TROUGH CROSSING THE ROCKIES...IS FORECAST TO DIG INTO TEXAS
AND OKLAHOMA ON MONDAY...FARTHER SOUTH THAN THE RECENT STORM.
2. STRONG RIDGING DEVELOPS AHEAD OF UPPER TROUGH FROM THE
MID-ATLANTIC TOWARDS OUR FORECAST AREA.
3. MODEL TRENDS OVERALL FROM THE GFS...CANADIAN AND ECMWF THE PAST
FEW DAYS HAVE BEEN SLOWER LIFTING THE STORM OUT OF THE SOUTHERN
PLAINS AND MORE TO THE SOUTHEAST...REPRESENTATIVE OF THE IMPACT THE
STRONG RIDGING AHEAD OF IT IS HAVING.
WHAT HAS BEEN INCONSISTENT...WHETHER THE HEAVIER BUT WEAKENING
DEFORMATION BAND ON THE NORTHWEST SIDE OF THE SYSTEM WILL IMPACT
PORTIONS OF THE AREA...OR STAY TO THE SOUTHEAST. TAKE FOR EXAMPLE
THE 23.12Z CANADIAN...WHICH OVER THE PAST FEW DAYS HAS BEEN A
SOUTHEAST SOLUTION...NOW HAS SHIFTED NORTHWEST TOWARDS THE 23.12Z
GFS WHICH HAS BEEN A MORE NORTHWEST SOLUTION ALL ALONG. THE 23.12Z
NAM HAS FOLLOWED SIMILARLY TO THE CANADIAN. LASTLY...THE 23.12Z
ECMWF HAS SHIFTED BACK MORE NORTHWEST COMPARED TO ITS 00Z RUN.
NO MATTER WHAT MODEL SOLUTION IS FOLLOWED...ANY PRECIPITATION
ASSOCIATED WITH THE SYSTEM...EITHER FROM THE DEFORMATION BAND OR
FROM AN INVERTED TROUGH EXTENDING NORTH FROM THE LOW...LOOKS TO HOLD
OFF TO OUR WEST AND SOUTH THROUGH 12Z TUESDAY. THIS MAKES SENSE WITH
THE BUILDING RIDGING ALOFT AND DRY AIR FLOW FROM HIGH PRESSURE
HEADING EAST INTO THE GREAT LAKES. IN FACT...THE DRY AIR FLOW ONLY
INTENSIFIES AS THE SYSTEM LIFTS NORTHEAST DUE TO THE WINDS
INCREASING. THUS...HAVE A DRY FORECAST FOR MONDAY AND MONDAY NIGHT.
FOR TUESDAY...FOLLOWED A CONSENSUS APPROACH ON PRECIPITATION CHANCES
FOR NOW GIVEN THE MODEL INCONSISTENCIES ON THE DEFORMATION BAND.
STILL...THE BEST CHANCES FOR SNOW ON TUESDAY WOULD OCCUR IN THE
SOUTHEAST 1/3 OF THE AREA. AMOUNTS RIGHT NOW WOULD BE MAYBE WORTHY
OF AN ADVISORY AT MOST. THE SYSTEM JUST REALLY WEAKENS AS IT LIFTS
NORTHEAST AND RUNS INTO THE RIDGE.
OUTSIDE OF THE SHORT TERM HIGHLIGHTS ABOVE...EXPECT THE MOST
SUNSHINE TOMORROW AFTER THE MORNING FOG/STRATUS MIX OUT. AS WE HEAD
INTO MONDAY AND TUESDAY...CIRRUS WILL DOMINATE THE AREA AND
EVENTUALLY LOWER CLOUDS COME TUESDAY. DESPITE THE HIGH
CLOUDS...THERE SHOULD BE ENOUGH SUN GETTING THROUGH TO COMBINE WITH
SLIGHTLY WARMING 925MB TEMPS TO BRING TEMPERATURES UP A LITTLE EACH
DAY. EVEN ON TUESDAY...WHEN THE SYSTEM APPROACHES...925MB TEMPS ARE
ONLY -2 TO -4C.
.LONG TERM...TUESDAY NIGHT THROUGH SATURDAY
255 PM CST SAT FEB 23 2013
THE LONG TERM FORECAST OVERALL IS FAIRLY QUIET. IN THE UPPER LEVEL
PATTERN...THE ECMWF/GFS/CANADIAN CONTINUE TO FORECAST THAT THE
WEAKENING STORM SYSTEM FROM TUESDAY IS GOING TO GET BOTTLED UP OVER
THE GREAT LAKES REGION...ONLY SLOWLY MOVING TO THE EAST. THERE ARE
TWO REASONS FOR THIS...1. THE SYSTEM IS HAVING TO GET THAT THROUGH
THE RIDGING AHEAD OF IT AND 2. THERE IS ANOTHER FAIRLY POTENT
SHORTWAVE TROUGH ON ITS HEELS COMING ACROSS THE SOUTHERN U.S. THAT
EVENTUALLY GETS ABSORBED. WHAT THIS MEANS FOR OUR AREA IS THAT WE
COULD SEE A GOOD 24 HOURS OR SO OF LIGHT SNOW FROM TUESDAY NIGHT
INTO WEDNESDAY...ASSOCIATED WITH MOISTURE WRAPPING AROUND THE UPPER
LOW. RAISED PRECIPITATION CHANCES SLIGHTLY...BUT FURTHER INCREASES
ARE LIKELY NEEDED. ONCE THE UPPER LOW SHIFTS EAST...THEN HIGH
PRESSURE BUILDS IN FROM THE U.S. AND CANADIAN PLAINS. HOWEVER...THE
HIGH PRESSURE AREA DOES NOT LOOK TO BUILD INTO THE AREA UNTIL
SATURDAY AT THE EARLIEST. A COMBINATION OF UPPER RIDGING BUILDING
OVER THE WESTERN U.S. AND TROUGHING HOLDING IN PLACE OVER THE
EASTERN U.S. LOOKS TO RESULT IN THIS SETUP. THEREFORE...A PROLONGED
PERIOD OF DRY...NORTHERLY FLOW IS EXPECTED. DESPITE THE NORTHERLY
FLOW...THE 850MB TEMPS BOTTOM OUT MAYBE AROUND -10C...THUS
TEMPERATURES SHOULD HANG JUST BELOW NORMAL.
&&
.AVIATION...THROUGH 18Z SUNDAY
1155 AM CST SAT FEB 23 2013
A SCATTERED TO BROKEN STRATUS DECK WILL BRING IFR CONDITIONS TO
KRST AND MVFR CONDITIONS TO KLSE THROUGH EARLY AFTERNOON. HIGH
PRESSURE IS EXPECTED TO BUILD IN LATE THIS AFTERNOON INTO THIS
EVENING WITH SKIES CLEARING AND WINDS BECOMING LIGHT AND VARIABLE
AT BOTH TAF SITES. AREAS OF FOG ARE EXPECTED TO DEVELOP AND COULD
BE LOCALLY DENSE AT TIMES. LIFR CONDITIONS WILL DEVELOP AT KRST
AROUND 9Z WITH VISIBILITIES FALLING TO 1/4 MILE. IFR CONDITIONS
ARE EXPECTED AT KLSE AROUND 9Z WITH VISIBILITIES FALLING TO 2SM.
THE FOG COULD FREEZE TO OBJECTS DEPOSITING A THIN LAYER OF FROST
OR ICE. THE FOG WILL DISSIPATE IN THE 14-16Z TIMEFRAME WITH
CONDITIONS GRADUALLY IMPROVING TO MVFR BY MID SUNDAY MORNING AND
EVENTUALLY OF VFR BY THE LATE MORNING HOURS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
255 PM CST SAT FEB 23 2013
WI...FREEZING FOG ADVISORY FROM 10 PM THIS EVENING TO 9 AM CST SUNDAY
FOR WIZ032>034-041-042-053>055-061.
MN...FREEZING FOG ADVISORY FROM 10 PM THIS EVENING TO 9 AM CST SUNDAY
FOR MNZ079-086>088-094>096.
IA...FREEZING FOG ADVISORY FROM 10 PM THIS EVENING TO 9 AM CST SUNDAY
FOR IAZ008>011-018-019-029-030.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...WETENKAMP
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1156 AM CST SAT FEB 23 2013
.SHORT TERM...TODAY THROUGH MONDAY NIGHT
319 AM CST SAT FEB 23 2013
FORECAST CHALLENGES GOING THROUGH EARLY NEXT WEEK REVOLVE AROUND
WHEN THE FLURRIES/SKIES CLEAR OUT TODAY/TONIGHT ALONG WITH WHEN THE
NEXT ROUND OF LIGHT SNOW MAY MOVE IN ON MONDAY.
CYCLONIC FLOW FROM THE SURFACE THROUGH THE UPPER ATMOSPHERE WILL
LINGER ACROSS THE REGION FOR MUCH OF TODAY BEFORE A SURFACE TO
UPPER LEVEL RIDGE AXIS PROPAGATES IN FROM THE WEST TONIGHT. WITH
THE CYCLONIC FLOW HANGING ON FOR MUCH OF TODAY...EXPECT THAT THE
CLOUD COVER AND FLURRIES/SNOW SHOWERS WILL CONTINUE AS WELL AND
THAT THE DRY AIR TO THE SOUTHWEST WILL STRUGGLE TO MOVE IN. BY 00Z
TONIGHT...THE 23.07Z RAP HAS THE SURFACE RIDGE ALIGNED ALONG THE
MISSISSIPPI RIVER...SO AT LEAST EXPECT THAT THE FLURRIES WILL HAVE
ENDED BY THEN ALONG AND WEST OF THE RIVER. HOWEVER...CLOUD COVER
MAY LINGER WITH THE UPPER RIDGE STILL IN THE DAKOTAS. HAVE PLAYED
CLOUD COVER A BIT ON THE PESSIMISTIC SIDE THROUGH TONIGHT AS A
RESULT.
BEYOND THIS THE PATTERN IS FAIRLY QUIET THROUGH THE REST OF THE
WEEKEND AS THE RIDGE SHIFTS TO THE EAST WITH TEMPERATURES AND
CLOUD COVER THE ONLY ISSUES TO CONTEND WITH. THERE IS NOT MUCH IN
THE WAY OF LOW LEVEL COLD AIR ADVECTION KICKING IN BEHIND THIS
SYSTEM...SO EXPECT THAT TEMPERATURES WILL REMAIN NEAR NORMAL
THROUGH MONDAY NIGHT.
THE FOCUS THEN GOES TO THE NEXT SYSTEM THAT COULD IMPACT THE AREA
WHICH IS A COMBINATION OF A NORTHERN STREAM WEAKENING MID LEVEL
SHORT WAVE TROUGH AND A SOUTHERN STREAM DEEPENING LOW. THE TREND
CONTINUES TO BE TO GO SLOWER WITH THE NORTHERN STREAM SHORT WAVE
AS A BLOCKING RIDGE ALONG THE ATLANTIC COAST STALLS OUT THE FLOW.
THE SURFACE REFLECTION FROM THIS SYSTEM IS A TROUGH THAT TRACKS
ACROSS THE DAKOTAS AND STALLS ACROSS MINNESOTA AS THE SOUTHERN
STREAM SYSTEM STARTS TO DEEPEN. THE 23.00Z GFS IS THE MOST ROBUST
WITH QPF EXTENDING NORTH ALONG THIS SURFACE TROUGH WHILE THE REST
OF THE GUIDANCE IS DRY. THEREFORE...HAVE BACKED OFF ON
PRECIPITATION CHANCES FOR MONDAY NIGHT AND KEPT THEM RELEGATED TO
PORTIONS OF SOUTH CENTRAL MINNESOTA INTO NORTHEAST IOWA.
.LONG TERM...TUESDAY THROUGH FRIDAY
319 AM CST SAT FEB 23 2013
THIS AFOREMENTIONED SOUTHERN STREAM SYSTEM APPEARS TO BE COMING
TOGETHER BY TUESDAY WITH THE 23.00Z GUIDANCE LOCKING IN ON A MORE
SOUTHERN TRACK WITH THIS SURFACE LOW. THE 23.00Z GFS/ECMWF/GEM ALL
ADVERTISE THIS LOW RUNNING FROM ST LOUIS OVER TO INDIANAPOLIS
TUESDAY WHICH SHOULD KEEP THE MAIN BAND OF SNOW OFF TO THE
SOUTHEAST. THE 23.00Z GFS IS FURTHEST TO THE NORTHWEST WHILE THE
GEM/ECMWF ARE NEARLY IDENTICAL WITH THEIR TRACK. HAVE BACKED OFF
ON SNOW CHANCES FOR TUESDAY ACROSS SOUTHWEST WISCONSIN AS A
RESULT. AFTER THIS SYSTEM MOVES THROUGH...ANOTHER MID LEVEL TROUGH
WILL DIG DOWN THROUGH THE NORTHWEST FLOW AND REINFORCE THE CUT OFF
CLOSED LOW ACROSS THE EASTERN US. THIS WILL KEEP CYCLONIC FLOW IN
PLACE ACROSS THE REGION THROUGH THURSDAY WITH SOME LIGHT SNOW
POSSIBLE. THE 23.00Z GEM IS THE DRIEST OF THE GUIDANCE AND FOCUSES
THIS TROUGH FURTHER TO THE SOUTH AND WOULD KEEP THE REGION ON THE
DRY SIDE. DESPITE THESE HIGHLY AMPLIFIED SYSTEMS MOVING THROUGH
THE UPPER MIDWEST...THE MAIN POOL OF COLD ARCTIC AIR IS CONFINED
TO FAR NORTHERN CANADA WITH 850MB TEMPERATURES IN THE 0C TO -10C
RANGE ACROSS THE SOUTHERN HALF OF CANADA. THUS...IT DOES NOT LOOK
LIKE TEMPERATURES WILL TAKE MUCH OF A DIP AROUND HERE AS THE
NORTHERLY FLOW SETS UP TOWARD MID WEEK.
&&
.AVIATION...THROUGH 18Z SUNDAY
1155 AM CST SAT FEB 23 2013
A SCATTERED TO BROKEN STRATUS DECK WILL BRING IFR CONDITIONS TO
KRST AND MVFR CONDITIONS TO KLSE THROUGH EARLY AFTERNOON. HIGH
PRESSURE IS EXPECTED TO BUILD IN LATE THIS AFTERNOON INTO THIS
EVENING WITH SKIES CLEARING AND WINDS BECOMING LIGHT AND VARIABLE
AT BOTH TAF SITES. AREAS OF FOG ARE EXPECTED TO DEVELOP AND COULD
BE LOCALLY DENSE AT TIMES. LIFR CONDITIONS WILL DEVELOP AT KRST
AROUND 9Z WITH VISIBILITIES FALLING TO 1/4 MILE. IFR CONDITIONS
ARE EXPECTED AT KLSE AROUND 9Z WITH VISIBILITIES FALLING TO 2SM.
THE FOG COULD FREEZE TO OBJECTS DEPOSITING A THIN LAYER OF FROST
OR ICE. THE FOG WILL DISSIPATE IN THE 14-16Z TIMEFRAME WITH
CONDITIONS GRADUALLY IMPROVING TO MVFR BY MID SUNDAY MORNING AND
EVENTUALLY OF VFR BY THE LATE MORNING HOURS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
319 AM CST SAT FEB 23 2013
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM....HALBACH
AVIATION...WETENKAMP