Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 02/25/13
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 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 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
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
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...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...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 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
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
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
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 NEWPORT/MOREHEAD CITY NC
948 PM EST SUN FEB 24 2013
.SYNOPSIS...
HIGH PRESSURE WILL BUILD IN FROM THE NORTHWEST TONIGHT THEN MOVE
OFF THE MID ATLANTIC COAST ON MONDAY. A WARM FRONT WILL APPROACH
FROM THE SOUTH MONDAY NIGHT. LOW PRESSURE WILL DEVELOP ON THE WARM
FRONT TUESDAY AND PASS TO THE WEST WITH ITS TRAILING COLD FRONT
CROSSING TUESDAY NIGHT. A COLD TROUGH OF LOW PRESSURE WILL SETTLE
OVER THE MID ATLANTIC STATES WEDNESDAY THROUGH THE END OF THE
WEEK.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
AS OF 945 PM SUNDAY...NOT MUCH CHANGE TO CURRENT FORECAST. SKIES
ARE CLEAR WITH A FEW PATCHES OF FOG ACROSS THE CWA. NO BIG CHANGES
TO THE CURRENT FORECAST WITH LOW TEMPERATURES STILL EXPECTED TO
FALL INTO THE MIDDLE AND UPPER 30S RANGING TO THE MIDDLE 40S ALONG
THE OUTER BANKS.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH 6 PM MONDAY/...
LOW AMPLITUDE RIDGE CROSSES THE AREA MONDAY AS SFC HIGH MOVES
OFFSHORE TO THE NE. SHUD SEE PLENTY OF SUN EARLY BUT INCREASING
AFTERNOON CLOUDS AHEAD OF A SOUTHERN STREAM SYSTEM AND DEVELOPING
ONSHORE BREEZE WILL HOLD HIGH TEMPS IN THE UPPER 40S TO LOWER 50S
MOST AREAS.
&&
.LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
AS OF 3 PM SUN...SFC HIGH PRES WILL BE RIDGING S INTO THE REGION
WITH RIDGING ALOFT TO START THE LONG TERM BUT CONDITIONS WILL
DETERIORATE MON NIGHT AS A ROBUST UPPER LEVEL CUT-OFF LOW CENTERED
NEAR THE ARKLATEX REGION AT 00Z TUE LIFTS NE TO THE OHIO RIVER
VALLEY THROUGH TUE NIGHT. CLOUDS WILL BE THICKENING AND LOWERING
THROUGH THE EVENING BUT MODELS IN GOOD AGREEMENT WITH PCPN HOLDING
OFF UNTIL AFTER MIDNIGHT...WITH STRONG ISENTROPIC LIFT SPREADING
FROM SOUTH TO NORTH AFTER 09Z. PERIODS OF MODERATE TO HEAVY RAIN
EXPECTED TUESDAY WITH A STRONG 50 KT LOW LEVEL JET TRANSPORTING
ABUNDANT MOISTURE ACROSS THE AREA...PW`S INCREASE TO 1.5"...AND GOOD
DIFLUENCE ALOFT AHEAD OF THE UPPER LOW. WIDESPREAD 1 TO 2" WILL BE
POSSIBLE WITH LOCALLY HIGHER AMOUNTS WHICH MAY BRING MINOR FLOODING
CONCERNS...ESPECIALLY ACROSS URBAN AND LOW LYING AREAS. THE WARM
FRONT WILL LIFT N ACROSS THE AREA TUE AFTERNOON WHICH WILL BRIEFLY
PLACE ERN NC IN THE WARM SECTOR OF THE SYSTEM WHICH MAY BRING JUST
ENOUGH INSTABILITY...MAINLY ELEVATED...TO PRODUCE A FEW
THUNDERSTORMS. WITH ABUNDANT SHEAR IN PLACE ANY THUNDERSTORMS THAT
DEVELOP COULD HAVE THE POTENTIAL TO PRODUCE DAMAGING WIND GUSTS AND
SPC HAS THE REGION IN A 5% PROBABILITY OF SEVERE. SHOWERS END TUE
EVENING WITH LOW PRES LIFTING NORTH AND ASSOCIATED COLD FRONT MOVING
ACROSS ERN NC.
THE CUT-OFF LOW WILL REMAIN QUASI-STATIONARY ACROSS THE NRN
MID-ATLANTIC STATES AND NEW ENGLAND THROUGH THE REST OF THE LONG
TERM. A MID LEVEL VORT MAX MOVES ACROSS THE AREA WED WHICH MAY BRING
AN ISOLATED SHOWER IF SUFFICIENT LOW LEVEL MOISTURE REMAINS...WHICH
WILL MAINLY BE NORTH OF HIGHWAY 70. TEMPS WILL BE SEASONABLE WITH
WRLY FLOW BRINGING HIGHS M50S TO AROUND 60 MOST AREAS. UPPER PATTERN
WILL BECOME HIGHLY AMPLIFIED ACROSS THE EASTERN CONUS BY THE WEEKEND
AS A ROBUST SHORTWAVE PIVOTS THROUGH THE FLOW ALOFT. A SERIES OF
MAINLY DRY COLD FRONTAL PASSAGES WILL MOVE THROUGH GIVEN THE
APPARENT LACK OF DEEP MOISTURE SOURCES IN THE OVERALL WESTERLY FLOW.
TEMPS WILL SHOW A GRADUAL COOLDOWN THROUGH THE END OF THE WEEK AND
WEEKEND WITH CAA BRINGING HEIGHT FALLS HIGHS IN THE MID 50S THU WILL
COOL DOWN 2-3 DEGREES EACH DAY WITH HIGHS SUNDAY EXPECTED IN THE MID
40S WITH H85 TEMPS COOLING TO AROUND -8C. LOWS LIKELY AT OR BLO
FREEZING INLAND THU NIGHT THROUGH SUN NIGHT.
&&
.AVIATION /03Z MONDAY THROUGH FRIDAY/...
SHORT TERM /THROUGH MONDAY AFTERNOON/
AS OF 635 PM SUN...A FEW PATCHES OF FOG MAY BRIEFLY REDUCE VSBY AS
KEWN ALREADY REPORTING 1 1/2 MILES IN LIGHT FOG. HOWEVER...MAINLY
VFR CONDITIONS WILL PREVAIL THROUGH THIS TAF CYCLE. LIGHT WINDS
AND CLEAR SKIES SHOULD LEAD TO GOOD RADIATIONAL COOLING OVERNIGHT
BUT DEWPOINTS SHOULD DROP PRECLUDING FOG/STRATUS FORMATION. WINDS
WILL VEER TO THE NNE BY TOMORROW MORNING AS HIGH PRESSURE
CONTINUES TO NOSE DOWN FROM THE NORTHWEST. FEW/SCT HIGH CLOUDS
WILL START TO FILTER INTO THE AREA FROM THE SOUTH AND WEST AS THE
NEXT SYSTEM APPROACHES.
LONG TERM /MON NIGHT THROUGH THURSDAY/...
AS OF 3 PM SUN...VFR CONDITIONS TO START MON NIGHT BUT CONDITIONS
DETERIORATE AFTER MIDNIGHT AS A ROBUST LOW PRES SYSTEM LIFT NW OF
THE AREA. SUB-VFR CONDITIONS LIKELY LATE MON NIGHT INTO TUE
EVENING...WITH IFR POSSIBLE TUE WITH HEAVIEST RAIN. ISOLATED TSTMS
WILL BE POSSIBLE TUE AFTERNOON AND EVENING. COULD SEE S/SE WIND
GUSTS AROUND 20-30 KT TUE AFTERNOON WITH STRONGER GUSTS IN TSTMS IF
THEY DEVELOP. PRED VFR CONDITIONS WILL RETURN WED THROUGH FRI.
&&
.MARINE...
SHORT TERM /THROUGH TONIGHT/...
AS OF 945 PM SUNDAY...LATEST RAP MODEL INDICATES A SURGE WILL WORK
ITS WAY DOWN THE COAST THROUGH THE OVERNIGHT HOURS. AS A RESULT...LIGHT
SW/W WILL BECOME NORTH AND INCREASE TO 15 TO 20 KNOTS WITH A GUSTS
TO 25 KTS AS THE HIGH PRESSURE OVER THE GREAT LAKES MOVES SOUTHEAST
AND THE CAA SURGE WORKS DOWN THE COAST. WINDS GRADUALLY VEER NE
AND DECREASE AS THE PRES GRADIENT EASES MON AFTERNOON. SEAS BUILD
TO 5-7 FT LATER TONIGHT IN THE MODERATE NORTH FLOW THEN SLOWLY
SUBSIDE MONDAY AFTN AS WINDS BEGIN TO VEER AND DECREASE.
LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
AS OF 3 PM SUN...UNSETTLED CONDITIONS EXPECTED THROUGH THE PERIOD.
CONDITIONS WILL QUICKLY DETERIORATE MON NIGHT INTO EARLY TUE MORNING
AS WARM FRONT AND AN AREA OF LOW PRESSURE LIFT INTO THE
AREA...FLOWING BECOMING SE AND INCREASING TO 15-25KT TUE WITH SEAS
BUILDING TO 7-12FT BY TUE EVENING. WINDS EXPECTED TO PEAK TUE
AFTERNOON AND EVENING WITH A PERIOD OF GALE FORCE CONDITIONS
POSSIBLE. A BRIEF PERIOD OF HIGH SURF CONDITIONS WILL ALSO BE
POSSIBLE GIVEN STRONG ONSHORE FLOW AND BREAKING WAVES 7-10FT. TUE
NIGHT THE SFC LOW WILL LIFT INTO THE MID-ATLANTIC WITH THE ATTENDANT
COLD FRONT MOVING THROUGH THE WATERS. GRADIENT WILL REMAIN TIGHTENED
THROUGH FRI WITH SW/W WINDS 15-25KT AND SEAS REMAINING AROUND 4-7 FT
THROUGH THU...THEN SUBSIDE TO BLO 6 FT FRI.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 PM EST MONDAY FOR AMZ152-154.
SMALL CRAFT ADVISORY UNTIL 11 AM EST MONDAY FOR AMZ135-150.
&&
$$
SYNOPSIS...BTC
NEAR TERM...CTC
SHORT TERM...BTC
LONG TERM...SK
AVIATION...CTC/SK
MARINE...CTC/BTC/SK
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...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 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...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 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...UPDATED
NWS CORPUS CHRISTI TX
551 PM CST SUN FEB 24 2013
.DISCUSSION...SEE 00Z AVIATION DISCUSSION.
&&
.AVIATION...MAIN ISSUES ARE STATUS/FOG AND TIMING OF FRONT. MOS IS
BRINGING FOG IN HARD OVERNIGHT EASTERN TAF REGIONS WHILE BUFKIT
MODEL SOUNDINGS ARE NOT REALLY SHOWING IT AS MUCH (IF AT ALL).
AM GOING TO GO WITH SOME IFR FOG AT KALI AND KVCT (KALI ALREADY
2SM BR) AS MODELS DO SHOW ADVECTION OF MIXING RATIOS OVERNIGHT
WHICH SHOULD HELP TO DEVELOP/CONTINUE FOG. AM GOING WITH LIFR CIGS
AT BOTH LOCATIONS AS WELL AFTER 06Z (KALI TEMPO AND KVCT SHORTLY
AFTER 06Z). WILL LEAVE BR OUT OF KCRP FOR NOW BUT MAY HAVE TO PUT
IN MVFR BR IF CONFIDENCE INCREASES...AND DO HAVE IFR CIGS. NO FOG
AT KLRD...BUT DO HAVE MVFR CIGS FOR A SHORT TIME BETWEEN 06Z AND
10Z. CONCERNING FROPA...PREVIOUS TAF TIMING LOOKS REASONABLE BASED
ON RUC13 OUTPUT AS WELL AS 4KM TTU MODEL OUTPUT...WITH STRONG WNW
WINDS STARTING AT KLRD ABT 10Z...13Z AT KALI...14Z AT KCRP...AND
16Z AT KVCT. ALSO INCLUDED SOME SHOWERS AT KVCT ABOUT 14Z WITH
WINDS BEGINNING TO SHIFT...AS FINE LINE OF SHOWERS EXPECTED TO GET
INTO AREA. STRONG WINDS (SUSTAINED AOA 30KT GUSTS ABT 40KT) DURING
THE LATE MORNING AND AFTERNOON. COULD HAVE WINDS DIMINISH BY 23Z
BUT WILL NOT HAVE ANOTHER LINE FOR THAT LATE IN THE TAF FORECAST
PERIOD.
&&
.PREV DISCUSSION... /ISSUED 420 PM CST SUN FEB 24 2013/
SHORT TERM (TONIGHT THROUGH MONDAY NIGHT)...GENERALLY QUIET
WEATHER UNTIL MONDAY. SLIGHT TO CHANCE POPS FOR LIGHT RAIN/SHOWERS
WILL EXIST OVER THE EASTERN CWA WITH DECENT MOISTURE AND
ISENTROPIC LIFTING. AN ISOLATED THUNDERSTORM WILL BE POSSIBLE
MAINLY OVER THE NORTHWESTERN CWA MAINLY ALONG THE FRONT AS IT WILL
PROVIDE THE BEST LIFT. THE MAIN CONCERN DEALS WITH THE NEXT COLD
FRONT THAT WILL MOVE THROUGH EARLY MONDAY MORNING.
TIGHTENING IN THE PRESSURE GRADIENT IN WAKE OF THE FRONT WILL LEAD
TO STRONG NORTHWESTERLY WINDS THROUGH THE DAY. WIND ADVISORIES
ARE IN EFFECT FOR ALL OF SOUTH TEXAS AFTER THE FRONT. CAA AND THE
STRONG WINDS SHOULD ALSO ALLOW TEMPERATURES TO REMAIN ON THE COOL
SIDE OF GUIDANCE. WINDS WILL SLOWLY DIMINISH LATE MONDAY
EVENING...HOWEVER BREEZY CONDITIONS WILL STILL BE POSSIBLE AS LOW
LEVEL LAPSE RATES REMAIN DECENT ENOUGH TO MIX WITH THE WINDS JUST
ABOVE THE SURFACE.
LONG TERM (TUESDAY THROUGH SATURDAY)...TROUGH AXIS WILL BE EAST OF
THE AREA TO BEGIN THE LONG TERM. STRONGER WINDS WILL PERSIST INTO
TUESDAY MORNING OVER THE GULF WATERS BUT RELAX DURING THE DAY AS
GRADIENT WEAKENS. TEMPS REBOUND ON TUESDAY WITH NEAR 70 ACROSS THE
VICTORIA CROSSROADS TO UPPER 70S OVER THE RIO GRANDE PLAINS. ANOTHER
UPPER LEVEL DISTURBANCE WILL DIVE SOUTHEAST IN TO THE PLAINS ON
WEDNESDAY BEFORE BEING ABSORBED INTO DEVELOPING EASTERN CONUS TROUGH.
ASSOCIATED FRONT WILL MOVE THROUGH SOUTH TEXAS ON WEDNESDAY...BUT
THIS FRONT WILL NOT BE AS STRONG AS THE MONDAY FRONT. SURFACE HIGH
WILL THEN SETTLE INTO THE REGION FOR WEDNESDAY NIGHT WITH CHILLY
TEMPS ACROSS THE AREA (MID 30S NORTHEAST TO MID 40S WEST). NORTHERLY
FLOW WILL PERSIST THROUGH THE WORK WEEK WITH ANOTHER REINFORCING
AREA OF HIGH PRESSURE ON FRIDAY...LEADING TO SLIGHTLY BELOW NORMAL
TEMPERATURES. PATTERN CHANGE TAKES SHAPE TOWARDS THE END OF THE
FORECAST WITH UPPER RIDGE OUT WEST/EASTERN CONUS TROUGH...LEAVING
SOUTH TEXAS IN A DRY NORTHWEST FLOW ALOFT. CHANCES FOR PRECIP IN THE
EXTENDED WILL REMAIN VERY LOW.
MARINE...GALE WARNINGS ARE IN EFFECT FOR ALL OF THE MARINE ZONES
AS STRONG WINDS DEVELOP IN WAKE OF THE COLD FRONT. CONDITIONS
SHOULD SLOWLY IMPROVE OVER THE BAYS MONDAY EVENING...HOWEVER SMALL
CRAFT ADVISORY CONDITIONS WILL REMAIN LIKELY.
FIRE WEATHER...THE COMBINATION OF STRONG NORTHWEST WINDS AND
VERY DRY AIR WILL LEAD TO EXTREME FIRE WEATHER DANGER CONDITIONS.
AS A RESULT...A RED FLAG WARNING IS IN EFFECT FOR ALL OF SOUTH
TEXAS MONDAY. WINDS WILL SLOWLY DIMINISH THROUGH LATE MONDAY
EVENING...HOWEVER WINDS MAY STILL BE ELEVATED TO CONTINUE AN
ELEVATED FIRE DANGER THREAT.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 62 70 42 73 48 / 20 20 0 0 0
VICTORIA 60 67 38 70 44 / 30 20 0 0 0
LAREDO 57 70 43 78 47 / 10 10 0 0 0
ALICE 60 69 41 75 45 / 20 10 0 0 0
ROCKPORT 63 68 46 68 51 / 20 20 0 0 0
COTULLA 56 66 37 73 43 / 10 10 0 0 0
KINGSVILLE 62 71 42 75 47 / 20 10 0 0 0
NAVY CORPUS 62 70 48 69 52 / 20 20 0 0 0
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...RED FLAG WARNING FROM 9 AM TO 8 PM CST MONDAY FOR THE FOLLOWING
ZONES: ARANSAS...BEE...CALHOUN...DUVAL...GOLIAD...JIM
WELLS...KLEBERG...LA SALLE...LIVE OAK...MCMULLEN...NUECES...
REFUGIO...SAN PATRICIO...VICTORIA...WEBB.
WIND ADVISORY FROM 9 AM TO 8 PM CST MONDAY FOR THE FOLLOWING
ZONES: ARANSAS...BEE...CALHOUN...DUVAL...GOLIAD...JIM
WELLS...KLEBERG...LA SALLE...LIVE OAK...MCMULLEN...NUECES...
REFUGIO...SAN PATRICIO...VICTORIA...WEBB.
GM...GALE WARNING FROM 9 AM MONDAY TO 3 AM CST TUESDAY FOR THE
FOLLOWING ZONES: BAYS AND WATERWAYS FROM BAFFIN BAY TO PORT
ARANSAS...BAYS AND WATERWAYS FROM PORT ARANSAS TO PORT
O`CONNOR...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.
&&
$$
GW/86...AVIATION
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
629 PM CST SUN FEB 24 2013
.SHORT TERM...TONIGHT THROUGH WEDNESDAY
306 PM CST SUN FEB 24 2013
CURRENTLY AS OF 21Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED RIDGING FROM JUST OFF THE CALIFORNIA COAST INTO SOUTHERN
ALBERTA...A POTENT SOUTHERN STREAM UPPER LOW OVER ARIZONA AND NEW
MEXICO...RIDGING BUILDING IN THE SOUTHERN STREAM AHEAD OF IT FROM
THE LOWER MISSISSIPPI RIVER VALLEY INTO OUR FORECAST AREA...AND A
NORTHERN STREAM SHORTWAVE TROUGH CROSSING SOUTH CENTRAL CANADA AND
NORTHWEST NORTH DAKOTA. SUBSIDENCE UNDER THE SOUTHERN STREAM UPPER
RIDGE COMBINED WITH PLENTY OF DRY AIR SEEN ON THE 12Z MPX AND DVN
SOUNDINGS HAS RESULTED IN A DRY DAY ACROSS THE FORECAST AREA.
VARYING CLOUD COVER ACROSS THE AREA. HAD ONE PATCH OF CIRRUS MOVE
ACROSS TOPPING THE RIDGE. MORE IMPORTANTLY...A STRATUS DECK LINGERS
NORTHEAST OF I-94...AND TO THE SOUTHWEST A STRATUS DECK HAS BEEN
EXPANDING NORTHEAST FROM EASTERN NEBRASKA TO AUSTIN MN AND MASON
CITY IA. THE FORMER STRATUS IS RELATED TO MOISTURE STILL TRAPPED
FROM FRIDAYS STORM...EVIDENT ON THE 12Z GRB SOUNDING. THE LATTER
STRATUS IS ALONG AN INVERTED SURFACE TROUGH...WHICH EXTENDS FROM
DEEPENING LOW PRESSURE IN WEST TEXAS INTO SOUTHWEST MN. AIRMASS HAS
WARMED QUITE A BIT WITH 850MB TEMPS OF -5C AT MPX AT 12Z COMPARED TO
-10C AT 12Z YESTERDAY. THIS WARMING HAS BEEN REFLECTED BY
TEMPERATURES IN THE FORECAST AREA ABOUT 5-10 DEGREES WARMER THAN
YESTERDAY.
SHORT TERM HIGHLIGHTS / CONCERNS...
1. POTENTIAL FOR FOG AGAIN TONIGHT AND MONDAY NIGHT -
DEWPOINTS THROUGH MIXING AND SOME PARTIAL SNOW MELTING HAVE RISEN
BACK UP TO AROUND 20 F. COOLING TONIGHT...EVEN UNDER THE STRATUS
DECK EXPANDING NORTHEAST...BRINGS UP THE CONCERN OF FALLING THROUGH
THESE CROSS-OVER TEMPERATURES AND RESULTING IN FOG. SREF
PROBABILITIES OF LESS THAN 1 MILE VISIBILITY AND HRRR VISIBILITY
PROGS INDICATE FOG FORMING AGAIN...AS SOON AS 03Z AND THEN
DISSIPATING BY 15Z. BOTH SUGGEST NORTHEAST IOWA INTO FAR SOUTHWEST
WI AND ACROSS TAYLOR/CLARK COUNTIES AS THE BEST CHANCES FOR FOG. OF
THEM...THINK THE FIRST AREA WOULD HAVE THE BEST CHANCE AS THEY
SHOULD REMAIN CLEAR THE LONGEST AND BE ABLE TO GO THROUGH THE
CROSS-OVER. THERE ARE MID/HIGH CLOUDS ACROSS NEBRASKA PROGGED TO
SPREAD IN DURING THE NIGHT...WHICH SHOULD DISRUPT THE FOG PROCESS.
FEEL THERE IS ENOUGH SIGNAL HERE TO JUST GO WITH PATCHY FREEZING FOG
ACROSS THE ENTIRE AREA TONIGHT...DISSIPATING AFTER MIDNIGHT EXCEPT
OVER TAYLOR/CLARK TO MATCH THE INCOMING MID/HIGH CLOUDS. WOULD NOT
COMPLETELY RULE OUT DENSE FOG EITHER...BUT WOULD LIKE TO SEE
DEWPOINTS RIGHT NOW A LITTLE HIGHER BEFORE MENTIONING DENSE FOG.
LOOKING AHEAD TO MONDAY NIGHT...THE SREF AGAIN POINTS TO POSSIBLE
FOG FORMATION OVER THE NORTH HALF OF WISCONSIN. THERE MIGHT BE A
LITTLE BETTER CHANCE AS MOST MODELS SHOW POTENTIAL FOR PARTIAL
CLEARING AFTER MIDNIGHT. THUS...INCLUDING A MENTION OF PATCHY
FREEZING FOG OVER TAYLOR/CLARK COUNTIES.
2. LIGHT QPF SIGNALS FROM GFS/NAM/REGIONAL CANADIAN/SREF TONIGHT
THROUGH MONDAY NIGHT -
24.12Z NAM/GFS/REGIONAL CANADIAN AND 24.15Z SREF POP FORECASTS HAVE
HIGHLIGHTED AN AREA OF LIGHT QPF POSSIBLE FROM SOUTHERN MN INTO THE
NORTH HALF OF WI TONIGHT THROUGH MONDAY NIGHT. THIS LIGHT
PRECIPITATION IS RELATED TO MOISTURE STUCK AT OR BELOW 900 MB AND
WEAK LIFT GETS APPLIED TO IT. THE MOISTURE IS DEFINITELY THERE NOTED
BY THAT STRATUS DECK ALREADY OVER NORTHWEST IOWA. THE LIFT COMES
FROM TWO FEATURES. THE FIRST IS A SURFACE TROUGH ACCOMPANYING THE
CURRENT SHORTWAVE TROUGH TRACKING ACROSS SOUTH CENTRAL CANADA...
WHICH APPROACHES THE AREA MONDAY NIGHT. THE SECOND IS THAT INVERTED
TROUGH WHICH IS PROGGED TO LINGER OVER WESTERN IOWA AND SOUTHWEST
MINNESOTA. SHOULD THIS PRECIPITATION OCCUR...WE COULD BE DEALING
WITH FLURRIES AND/OR FREEZING DRIZZLE...WITH THE LATTER FAVORED MORE
FOR MONDAY NIGHT WHEN NO ICE IS PRESENT ALOFT. HOWEVER...FEEL THIS
WEAK LIFT IS OVERDONE. MOST OF THESE MODELS SUGGEST THERE SHOULD
HAVE PRECIPITATION ALREADY AND THERE HAS NOT BEEN. ADDITIONALLY...
THERE IS BASICALLY NO ISENTROPIC LIFT TO SPEAK OF ALONG THE INVERTED
TROUGH. THUS...THINKING THE LIGHT QPF MIGHT BE MORE OF A SIGNAL FOR
THE LOW CLOUDS AND FOG POTENTIAL...AND THERE WAS FOG THIS MORNING.
SO HAVE KEPT THE FORECAST DRY FOR NOW FOR TONIGHT THROUGH MONDAY
NIGHT.
3. THE SOUTHERN STREAM UPPER LOW AND DEVELOPING WINTER STORM -
MODEL TRENDS...FLIP-FLOPPING CONTINUES ON WHETHER OR NOT THE
DEFORMATION BAND ON THE NORTHWEST SIDE OF THE STORM IMPACTS PORTIONS
OF THE AREA FOR TUESDAY INTO TUESDAY NIGHT. THERE APPEARS TO BE 2
REASONS FOR THIS...ONE ON HOW MUCH THE UPPER LOW WILL DECAY AS IT
RUNS INTO THE DOWNSTREAM UPPER RIDGE...AND THE SECOND RELATED TO A
KICKER SHORTWAVE DROPPING INTO NEW MEXICO ON TUESDAY ALONG WITH THE
WAVELENGTH BETWEEN IT AND THE UPPER LOW. THE LATEST EXAMPLE OF
FLIP-FLOPPING IS THE 24.12Z NAM...WHICH THE PREVIOUS 2 RUNS WENT
MORE SOUTHEAST AND BASICALLY HAD THE AREA DRY. NOW THE 24.12Z NAM
SHIFTED NORTHWEST... PRODUCING 0.50 TO 1 INCH OF LIQUID EQUIVALENT
FROM FAYETTE COUNTY EAST TO GRANT COUNTY. THIS WOULD EASILY BE
WORTHY OF AN ADVISORY AND POSSIBLY A WARNING. LATEST 24.18Z NAM IS
SIMILAR TO THE 12Z BUT CAME DOWN A BIT QPF WISE. THE GFS HAS BEEN
ONE OF THE MORE STABLE MODELS WITH THE PAST 6 TO 8 RUNS STAYING
FAIRLY CONSISTENT...BRINGING THE BAND INTO THE SOUTHEAST 1/2 OF THE
AREA TUESDAY AFTERNOON AND LINGERING IT INTO THE DAY WEDNESDAY. THE
QPF IS NOT NEARLY AS HEAVY AS THE NAM...UP TO 0.40 INCHES...BUT
WOULD BE ADVISORY WORTHY. THE LAST FEW CANADIAN RUNS INCLUDING THE
LATEST 24.12Z RUN HAVE BEEN SIMILAR TO THE GFS. LASTLY...THE 24.12Z
RUN OF THE ECMWF SHIFTED BACK TO THE NORTHWEST TOWARDS ITS 23.12Z
RUN...COMING MORE IN-LINE WITH THE GFS AND SAYING THAT THE 24.00Z
RUN WAS A FLUKE.
FOR THE FORECAST...SINCE THE 24.12Z MODELS ARE IN PRETTY GOOD
AGREEMENT THAT OUR SOUTHEAST END WILL BE IMPACTED TUESDAY INTO
TUESDAY NIGHT...AND GIVEN THE MORE STABLE NATURE OF THE GFS/CANADIAN
IMPACTING THE SAME AREA...HAVE RAISED PRECIPITATION CHANCES. NOW THE
SYSTEM AS IT LIFTS OUT OF THE SOUTHERN PLAINS AND INTO ILLINOIS WILL
BE WEAKENING...DUE TO IT RUNNING INTO THE RIDGING BUILT UP AHEAD OF
IT AS MENTIONED EARLIER AND THE SYSTEM GOING THROUGH THE OCCLUSION
PROCESS. THUS...THE IDEA MODELS HAVE SUGGESTED OF QPF DIMINISHING
DUE TO WEAKENING FORCING ALOFT SEEMS REASONABLE. SO AT THIS TIME...
ONLY THINKING MAYBE A MINIMAL ADVISORY WOULD BE NEEDED AT MOST...FOR
FAYETTE COUNTY EAST TO GRANT COUNTY. THINGS COULD STILL CHANGE...
THOUGH. THE NORTHWEST HALF OF THE FORECAST AREA MAY NOT GET MUCH IF
ANYTHING OUT OF THIS BRUSH BY FROM THE STORM...BUT THE CYCLONIC FLOW
AND MOISTURE WRAPPING AROUND WARRANTS KEEPING SOME 20-40
PRECIPITATION CHANCES. THESE CHANCES GO INTO WEDNESDAY...THOUGH THE
24.12Z ECMWF/CANADIAN WOULD SUGGEST THE PRECIPITATION COULD END
FASTER WEST TO EAST.
OUTSIDE THE ISSUES NOTED ABOVE...DESPITE THE APPROACH OF THE STORM
SYSTEM...HIGH TEMPERATURES SHOULD CLIMB UP TO AROUND NORMAL. PART OF
THIS IS DUE TO THE 925MB TEMPS HOLDING AROUND -4C EACH DAY...ABOUT 2
C WARMER THAN TODAY. THE SECOND IS THAT EVEN IF WE HAVE TO DEAL WITH
CLOUD ISSUES...THE HIGHER SUN ANGLE CAN HELP MIX BETTER NOW. MEDFORD
WI IS A GOOD EXAMPLE TODAY MANAGING TO HIT 30F DESPITE HAVING LOW
CLOUDS AROUND ALL DAY AND 925MB TEMPS AROUND -6C.
.LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY
306 PM CST SUN FEB 24 2013
THE LONG TERM FORECAST CONTINUES TO LOOK QUIET. GOOD MODEL AGREEMENT
CONTINUES AMONGST THE 24.12Z ECMWF/GFS/CANADIAN AND ECMWF
ENSEMBLES...WHICH SHOW RIDGING BUILDING UP OVER THE WESTERN U.S.
THROUGH SATURDAY WHILE TROUGHING HANGS IN PLACE OVER THE EASTERN
U.S.. THE FORECAST AREA IS CAUGHT IN THE MIDDLE BETWEEN THE
TWO...FAVORING A RIDGE OF HIGH PRESSURE WHICH SLOWLY BUILDS EAST
INTO THE FORECAST AREA DURING THIS PERIOD. THERE ARE INDICATIONS OF
A SHORTWAVE TROUGH DROPPING SOUTH THROUGH THE AREA ON FRIDAY...BUT
THERE ARE BOTH UNCERTAINTIES EXACTLY ON WHERE IT TRACKS AND WHETHER
IT WILL HAVE ENOUGH MOISTURE TO PRODUCE PRECIPITATION. THEREFORE...
AFTER SOME LINGERING SMALL PRECIPITATION CHANCES OVER WISCONSIN
AREAS WEDNESDAY NIGHT ASSOCIATED WITH THE SLOWLY DEPARTING AND
WEAKENING STORM TO OUR EAST...HAVE A DRY FORECAST FOR THURSDAY INTO
SATURDAY. HEADING INTO SUNDAY...A MORE POTENT SHORTWAVE TROUGH LOOKS
TO CRASH THROUGH THE WESTERN U.S. RIDGE...BUT ONLY MAKE IT INTO THE
NORTHERN ROCKIES BY 00Z MONDAY. IT SHOULD BE ENOUGH TO PUSH SOME OF
THE UPPER RIDGE EAST...ALLOWING THE SURFACE HIGH PRESSURE RIDGE TO
AT LEAST MOVE OVER IF NOT SHIFT OFF TO THE EAST FORECAST AREA.
NEEDLESS TO SAY...ANOTHER DRY DAY IS ANTICIPATED SUNDAY.
TEMPERATURES ARE A LITTLE TOUGH GIVEN A NORTHERLY FLOW PRESENT WHICH
BRINGS DOWN SOME COOLER AIR FOR MUCH OF THE PERIOD. HOWEVER...IT IS
NOT THAT COLD...NOTED BY 850MB TEMPS AT MOST DROPPING TO -8 TO -12C
BY FRIDAY. ANY SUNSHINE THAT OCCURS...WHICH MORE COULD HAPPEN IF THE
ECMWF IS RIGHT...WILL ALLOW FOR GOOD MIXING. THUS HAVE LEFT A
CONSENSUS APPROACH WHICH YIELDS HIGHS JUST SLIGHTLY BELOW NORMAL.
&&
.AVIATION...TONIGHT AND TUESDAY
626 PM CST SUN FEB 24 2013
A CHALLENGING CLOUD AND FOG FORECAST OVERNIGHT INTO MONDAY. AT
00Z...A NORTHEAST-SOUTHWEST ORIENTED MVFR STRATUS DECK IS LOCATED
FROM SERN MN TO OMAHA NEBRASKA. KRST NOW IS IN THIS STRATUS...
WHICH IS SPREADING SLOWLY NORTHEAST. THIS WILL WORK INTO KLSE
SHORTLY. SOME HIGHER CLOUD OVER THE TOP OF THE MVFR STRATUS IS ALSO
SPREADING NORTHEAST FROM THE BIGGER STORM SYSTEM OVER THE SOUTHERN
PLAINS. WITH LIGHT WINDS AND SURFACE RIDGING IN PLACE AND LIGHT
WINDS...AS OVERNIGHT TEMPERATURES COOL...THE STRATUS IS EXPECTED
TO SLOWLY LOWER AS THE BOUNDARY LAYER SATURATES.
AT THIS TIME THE NEW TAFS HAVE SLOWED THE DETERIORATION TO IFR AT
KRST TO AFTER 06Z. BUT HAVE ALSO LOWERED THE VSBYS TO 1 MILE BY
MORNING...AND IT COULD BE LIFR CIG/VSBY SHOULD THE CONDITIONS COME
TOGETHER RIGHT AND THE SECOND LAYER OF CLOUD ABOVE THE STRATUS IS
MINIMAL.
THOSE WITH FLYING INTERESTS IN THE MORNING SHOULD AT LEAST PLAN ON
LOWER MVFR...POSSIBLY DOWN TO LIFR.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
306 PM CST SUN FEB 24 2013
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...BAUMGARDT
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
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 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 MARQUETTE MI
338 AM EST MON FEB 25 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 337 AM EST MON FEB 25 2013
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW SPLIT FLOW
DOMINATING THE FLOW OVER NAMERICA. RDG IN THE NRN BRANCH IS PRESENT
FM JAMES BAY INTO THE UPR GRT LKS TO THE W OF DEPARTING CLOSED LO IN
SE CANADA/NEW ENGLAND...AND A SFC HI PRES RDG EXTENDS FM NE ONTARIO
THRU ECENTRAL UPR MI INTO THE UPR MIDWEST. WITH DRY AIR AOA H8 AS
SHOWN ON 00Z APX/GRB RAOBS AND LARGER SCALE SUBSIDENCE UNDER THE
RDG...THERE IS NO PCPN IN THE AREA. EVEN LES IS ABSENT WITH LLVL
ACYC FLOW AND H85 TEMPS -6C AT INL AND GRB. DESPITE PASSAGE OF SFC
RDG AXIS...QUITE A BIT OF LO CLD LINGERS WITH SOME MSTR/RELATIVELY
HI SFC DEWPTS TRAPPED BLO SUBSIDENCE INVRN H825-875 SHOWN ON THE 00Z
APX/GRB RAOBS. SOME CLRG HAS OCCURRED OVER THE W AND NEAR THE WI
BORDER INTO NE MN/NRN WI...WHERE SOME LLVL DRY AIR SHOWN ON THE 00Z
GRB/MPX RAOBS HAS SHIFTED TO THE N. WHERE SKIES HAVE CLRD...TEMPS
FELL OFF SHARPLY IN THE PRESENCE OF NEAR CALM WINDS. SOME PATCHY
FOG/ST HAS ALSO DVLPD...SO THE CLRG HOLES ARE IN SOME CASES SHORT
LIVED. ALTHOUGH THERE ARE MORE HOLES IN THE LO CLDS OVER FAR NRN
WI/NE MN...MORE LO/MID CLDS ARE STREAMING NEWD INTO CNTRL MN/WI IN
THE LLVL SW FLOW BTWN RDG AXIS OVER UPR MI AND LO PRES TROF
EXTENDING FM LK WINNIPEG INTO THE NRN PLAINS ASSOCIATED WITH PAIR OF
NRN BRANCH DISTURBANCES. A POTENT DISTURBANCE IN THE THE SRN BRANCH
IS PRESENT OVER THE SRN ROCKIES.
MAIN FCST CONCERNS IN THE SHORT TERM ARE TRICKY CLD TRENDS/IMPACT ON
TEMPS.
DESPITE SOME DIURNAL HEATING FM INCRSG SUN ANGLE AND SW FLOW ON THE
BACK SIDE OF HI PRES THAT WL ELIMINATE ANY LK SUP INFLUENCE AND
ADVECT SOME DRIER AIR THAT HAS CAUSED CLRG OVER NW WI...RECENT
TRENDS INDICATE LO CLDS MIGHT PROVE QUITE RESILIENT OVER THE CWA
WITH MORE MORE LO CLDS TENDING TO FORM OVER NRN WI. THE WINDOW FOR
CLRG WL BE RELATIVELY SHORT AS WELL BECAUSE BOTH 00Z NAM/GFS
INDICATE CLDS NOW STREAMING NEWD TOWARD CENTRAL WI AHEAD OF PAIR OF
SLOWLY APRCHG NRN BRANCH DISTURBANCES WL ARRIVE AT THE WI BORDER
LATER THIS MRNG. WITH ABUNDANT CLD COVER MORE LIKELY...WL TEND
TOWARD THE LOWER END OF GUIDANCE FOR MAX TEMPS...WHICH IS IN GOOD
AGREEMENT WITH GOING FCST. EXPECT THE HIER MAX TEMPS OVER THE
NCENTRAL FM BARAGA-MQT WHERE LLVL SSW FLOW DOWNSLOPES.
TNGT...AS PAIR OF NRN BRANCH SHRTWVS SHIFT E INTO THE UPR LKS...
GUIDANCE SHOWS THESE DISTURBANCES FADING UNDER LARGER SCALE HGT
RISES ASSOCIATED WITH BLDG UPR RDG ON NRN FLANK OF STRONGER SRN
BRANCH DISTURBANCE MOVING INTO THE MID-MS RIVER VALLEY. ALTHOUGH
LLVL FLOW TENDS ACYC...WINDS ARE FCST TO BE LGT. SO RATHER MOIST
LLVLS WL BE LINGERING IN THE ABSENCE OF SGNFT LLVL DRYING. THE
QUESTION IS WHETHER LARGER SCALE SUBSIDENCE WL RESULT IN THE BREAK
UP OF THIS LO CLD. IN THE ABSENCE OF SGNFT LLVL DRYING AND IN THE
PRESENCE OF DIURNAL COOLING...SUSPECT THE RESULT WL BE LINGERING LO
CLDS THRU THE NGT WITH SUBSIDENCE STRENGTHENING THE INVRN THAT TRAPS
THIS MSTR. CONSIDERING THE UNCERTAINTY...MADE FEW CHGS TO GOING MIN
TEMPS FCST. IF THE LO CLDS ARE MORE PERSISTENT...FCST MIN TEMPS IN
THE UPR TEENS/LO 20S WL HAVE TO BE RAISED.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 337 AM EST MON FEB 25 2013
UPPER MICHIGAN LOOK TO BE TAKING A BREAK FROM THE MODERATE TO HEAVY
SNOW THAT HAS BEEN COMMON PLACE OVER THE PAST WEEK OR SO.
THE CURRENT 500MB LOW SWINGING ACROSS NORTHERN TEXAS THIS MORNING
SHOULD BE OVER NORTHERN ARKANSAS/SOUTHERN MISSOURI BY 12Z
TUESDAY...WITH THE RIDGE EXTENDING FROM THE ATLANTIC BACK THROUGH
UPPER MICHIGAN/LAKE SUPERIOR/NORTHERN MINNESOTA.
THE 500MB RIDGE WILL BE QUICKLY PUSHED NORTH OF THE AREA DURING THE
DAY TUESDAY...WITH THE THEN NEARLY STACKED SFC-500MB SHOULD BE ABLE
TO LIFT TO SOUTHERN ILLINOIS/INDIANA. E-ENE WINDS WILL BE ON THE
INCREASE ACROSS UPPER MICHIGAN...AND IN PARTICULAR ALONG LAKE
MICHIGAN. WITH SURFACE TEMPERATURES IN THE LOW 30S...AND 850MB TEMPS
HOVERING AROUND -3C NO LAKE EFFECT SNOW IS EXPECTED. IN FACT...DRY
WEATHER SHOULD BE THE RULE THROUGH TUESDAY EVENING.
THE 25/00Z NAM IS A STRONGER FAR NORTHERN OUTLIER WITH THE 500MB
LOW...BRINGING THE 500MB LOW OVER CENTRAL LOWER MI BY 18Z WEDNESDAY.
THE CONSENSUS OF THE GFS/ECMWF/CANADIAN HAS THE FEATURE SOUTH OF
DETROIT... NORTHERN OHIO...OR ACROSS NORTHWESTERN PENNSYLVANIA. THE
DIVERGENCE OF THE NAM SOLUTION IS MOST DRAMATIC AFTER 00Z
WEDNESDAY...AND WILL THEREFORE NOT BE UTILIZED IN OUR ONGOING
FORECAST BEYOND THAT POINT. TO A LESSER EXTENT THE CANADIAN BRIDGES
THE GAP BETWEEN THE FASTER GFS/ECMWF AND THE NORTHWESTERLY NAM...BUT
ENDS UP RUNNING APPROXIMATELY 12HRS BEHIND THE ECMWF BY THURSDAY /AT
500MB ACROSS NEW YORK AND THE NEW ENGLAND STATES. MAY NEED TO ADD
FLURRIES FOR UPSLOPE AREAS OF NORTH CENTRAL UPPER MICHIGAN NEAR LAKE
SUPERIOR LATE WEDNESDAY AFTERNOON ON.
EXPECT A SHORTWAVE TO SWING ACROSS ONTARIO WEDNESDAY NIGHT INTO
THURSDAY...BUT HAVE LITTLE INFLUENCE ON OUR WEATHER OTHER THAN
KEEPING CLOUDS OVERHEAD. 850MB TEMPS WILL BE ABLE TO DROP TO AROUND
-8C THURSDAY AS COOLER AIR PUSHES IN BEHIND THE MAIN LOW. WITH N-NNE
WINDS OFF LAKE SUPERIOR THERE WILL BE AN INCREASED CHANCE OF LIGHT
LAKE EFFECT SNOW SHOWERS...WITH A SLIGHT INCREASE IN LOW LEVEL
MOISTURE...DESPITE A STRONG INVERSION NOTED OFF THE GFS HOVERING
NEAR 850MB. THE DGZ LOOKS TO REBOUND...ALTHOUGH THIN /ABOUT 50MB
THICK/ LATE WEDNESDAY NIGHT THROUGH SATURDAY MORNING.
ANOTHER 500MB RIDGE WILL BE ABLE TO PUSH ACROSS THE UPPER GREAT
LAKES THURSDAY THROUGH MUCH OF FRIDAY. EXPECT COOLER AIR TO FILTER
IN AGAIN FRIDAY NIGHT...AND TAKE HOLD OF THE UPPER GREAT LAKES BY
SUNDAY AS 850MB TEMPS FALL FROM AROUND -10C TO -13 OR -14C. WIND
DIRECTION DOES NOT CHANGE MUCH DURING THIS TIME...WITH FAIRLY STEADY
N-NE WINDS SLIDING IN OFF LAKE SUPERIOR. AS A RESULT...IT WILL BE
DIFFICULT TO TAKE OUT THE MENTION OF LIGHT SNOW SHOWERS NEAR LAKE
SUPERIOR /EVEN IF IT IS JUST A SLIGHT CHANCE/...DESPITE THE STRONG
SURFACE HIGH STRETCHING FROM NORTHERN HUDSON BAY THROUGH ONTARIO AND
PORTIONS OF LAKE SUPERIOR THURSDAY NIGHT THROUGH SUNDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1231 AM EST MON FEB 25 2013
GIVEN FAIRLY LOW DEWPOINT DEPRESSIONS AND THE OBSERVANCE OF PATCHY
FOG FORMING OVER NRN WI...HAVE DECIDED TO INCLUDE A MENTION OF MVFR
OR EVEN IFR VSBYS IN FOG AT ALL TAF SITES LATER TONIGHT WITH MVFR
CIGS. ANY FOG SHOULD LIFT BY LATE MON MORNING AND EXPECT MVFR CLOUDS
TO LIFT BY AFTERNOON WITH ADVECTION OF DRIER AIR AT LOW-LVLS IN SW
FLOW.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 337 AM EST MON FEB 25 2013
A RIDGE OF HIGH PRESSURE JUST EAST OF LAKE SUPERIOR WILL REMAIN OVER
THE UPPER GREAT LAKES THROUGH TONIGHT. EXPECT LOW PRESSURE OVER THE
SOUTHERN PLAINS TO TRACK NORTHEAST ACROSS THE MID MISSISSIPPI VALLEY
ON TUESDAY...BEFORE STALLING OVER THE LOWER GREAT LAKES ON
WEDNESDAY. A PROLONGED PERIOD OF N TO NE WINDS CAN BE
EXPECTED...WITH WINDS OF 15 TO 30KTS TUESDAY INTO FRIDAY. A FEW GALE
FORCE GUSTS TO 35 KNOTS WILL BE POSSIBLE THURSDAY OVER MAINLY
CENTRAL LAKE SUPERIOR. THE LOW WILL THEN MOVE EAST THURSDAY THROUGH
FRIDAY AS HIGH PRESSURE OF NOSES SOUTHWARD INTO NORTHERN
ONTARIO...WITH LIGHTER WINDS TAKING HOLD.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...KF
AVIATION...VOSS/KC
MARINE...KF
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
105 AM EST MON FEB 25 2013
.SYNOPSIS...
HIGH PRESSURE WILL BUILD IN FROM THE NORTHWEST TONIGHT THEN MOVE
OFF THE MID ATLANTIC COAST ON MONDAY. A WARM FRONT WILL APPROACH
FROM THE SOUTH MONDAY NIGHT. LOW PRESSURE WILL DEVELOP ON THE WARM
FRONT TUESDAY AND PASS TO THE WEST WITH ITS TRAILING COLD FRONT
CROSSING TUESDAY NIGHT. A COLD TROUGH OF LOW PRESSURE WILL SETTLE
OVER THE MID ATLANTIC STATES WEDNESDAY THROUGH THE END OF THE
WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 100 AM MONDAY...A WEAK EAST-WEST BOUNDARY NEAR THE PAMLICO
RIVER AS SEEN AS A FINE LINE IN THE DOPPLER RADAR IMAGERY..IS
MOVING RAPIDLY SOUTHWARD ACROSS EASTERN NC LATE TONIGHT. MAIN
EFFECT IS FOR WINDS TO INCREASE OUT OF THE NORTH AND NORTHEAST
BEHIND IT WHICH IS DISSIPATING THE PATCHES OF LOCALLY DENSE FOG
WHICH HAVE FORMED ACROSS THE AREA LATE IN THE EVENING. EXPECT MOST
IF NOT ALL OF THE FOG TO DIMINISHED BY 09Z. SKIES WILL BE CLEAR
FOR THE REMAINDER OF THE NIGHT BEHIND THE BOUNDARY AS HIGH
PRESSURE BUILDS INTO THE AREA FROM THE NORTH. TEMPERATURES STILL
EXPECTED TO FALL INTO THE MIDDLE AND UPPER 30S RANGING TO THE
MIDDLE 40S ALONG THE OUTER BANKS.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 AM TUESDAY/...
LOW AMPLITUDE RIDGE CROSSES THE AREA MONDAY AS SFC HIGH MOVES
OFFSHORE TO THE NE. SHUD SEE PLENTY OF SUN EARLY BUT INCREASING
AFTERNOON CLOUDS AHEAD OF A SOUTHERN STREAM SYSTEM AND DEVELOPING
ONSHORE BREEZE WILL HOLD HIGH TEMPS IN THE UPPER 40S TO LOWER 50S
MOST AREAS.
&&
.LONG TERM /TUESDAY THROUGH MONDAY/...
AS OF 3 PM SUN...SFC HIGH PRES WILL BE RIDGING S INTO THE REGION
WITH RIDGING ALOFT TO START THE LONG TERM BUT CONDITIONS WILL
DETERIORATE MON NIGHT AS A ROBUST UPPER LEVEL CUT-OFF LOW CENTERED
NEAR THE ARKLATEX REGION AT 00Z TUE LIFTS NE TO THE OHIO RIVER
VALLEY THROUGH TUE NIGHT. CLOUDS WILL BE THICKENING AND LOWERING
THROUGH THE EVENING BUT MODELS IN GOOD AGREEMENT WITH PCPN HOLDING
OFF UNTIL AFTER MIDNIGHT...WITH STRONG ISENTROPIC LIFT SPREADING
FROM SOUTH TO NORTH AFTER 09Z. PERIODS OF MODERATE TO HEAVY RAIN
EXPECTED TUESDAY WITH A STRONG 50 KT LOW LEVEL JET TRANSPORTING
ABUNDANT MOISTURE ACROSS THE AREA...PW`S INCREASE TO 1.5"...AND GOOD
DIFLUENCE ALOFT AHEAD OF THE UPPER LOW. WIDESPREAD 1 TO 2" WILL BE
POSSIBLE WITH LOCALLY HIGHER AMOUNTS WHICH MAY BRING MINOR FLOODING
CONCERNS...ESPECIALLY ACROSS URBAN AND LOW LYING AREAS. THE WARM
FRONT WILL LIFT N ACROSS THE AREA TUE AFTERNOON WHICH WILL BRIEFLY
PLACE ERN NC IN THE WARM SECTOR OF THE SYSTEM WHICH MAY BRING JUST
ENOUGH INSTABILITY...MAINLY ELEVATED...TO PRODUCE A FEW
THUNDERSTORMS. WITH ABUNDANT SHEAR IN PLACE ANY THUNDERSTORMS THAT
DEVELOP COULD HAVE THE POTENTIAL TO PRODUCE DAMAGING WIND GUSTS AND
SPC HAS THE REGION IN A 5% PROBABILITY OF SEVERE. SHOWERS END TUE
EVENING WITH LOW PRES LIFTING NORTH AND ASSOCIATED COLD FRONT MOVING
ACROSS ERN NC.
THE CUT-OFF LOW WILL REMAIN QUASI-STATIONARY ACROSS THE NRN
MID-ATLANTIC STATES AND NEW ENGLAND THROUGH THE REST OF THE LONG
TERM. A MID LEVEL VORT MAX MOVES ACROSS THE AREA WED WHICH MAY BRING
AN ISOLATED SHOWER IF SUFFICIENT LOW LEVEL MOISTURE REMAINS...WHICH
WILL MAINLY BE NORTH OF HIGHWAY 70. TEMPS WILL BE SEASONABLE WITH
WRLY FLOW BRINGING HIGHS M50S TO AROUND 60 MOST AREAS. UPPER PATTERN
WILL BECOME HIGHLY AMPLIFIED ACROSS THE EASTERN CONUS BY THE WEEKEND
AS A ROBUST SHORTWAVE PIVOTS THROUGH THE FLOW ALOFT. A SERIES OF
MAINLY DRY COLD FRONTAL PASSAGES WILL MOVE THROUGH GIVEN THE
APPARENT LACK OF DEEP MOISTURE SOURCES IN THE OVERALL WESTERLY FLOW.
TEMPS WILL SHOW A GRADUAL COOLDOWN THROUGH THE END OF THE WEEK AND
WEEKEND WITH CAA BRINGING HEIGHT FALLS HIGHS IN THE MID 50S THU WILL
COOL DOWN 2-3 DEGREES EACH DAY WITH HIGHS SUNDAY EXPECTED IN THE MID
40S WITH H85 TEMPS COOLING TO AROUND -8C. LOWS LIKELY AT OR BLO
FREEZING INLAND THU NIGHT THROUGH SUN NIGHT.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
SHORT TERM /THROUGH MONDAY AFTERNOON/
AS OF 100 AM SUNDAY...PATCHES OF LOCALLY DENSE FOG WILL OCCUR AT
THE SOUTHERN TAF SITES THROUGH 08Z THEN A WEAK BOUNDARY MOVING
SOUTHWARD ACROSS THE AREA WILL CAUSE THE WINDS TO INCREASE OUT OF
THE NORTH AND NORTHEAST AND DISSIPATE THE FOG. THEREAFTER
EXPECTING VFR CONDITIONS FOR THE REMAINDER OF THE TAF PERIOD AS
HIGH PRESSURE BUILDS IN WITH HIGH CLOUDS THICKENING AND LOWERING
THIS AFTERNOON.
LONG TERM /MON NIGHT THROUGH THURSDAY/...
AS OF 3 PM SUN...VFR CONDITIONS TO START MON NIGHT BUT CONDITIONS
DETERIORATE AFTER MIDNIGHT AS A ROBUST LOW PRES SYSTEM LIFT NW OF
THE AREA. SUB-VFR CONDITIONS LIKELY LATE MON NIGHT INTO TUE
EVENING...WITH IFR POSSIBLE TUE WITH HEAVIEST RAIN. ISOLATED TSTMS
WILL BE POSSIBLE TUE AFTERNOON AND EVENING. COULD SEE S/SE WIND
GUSTS AROUND 20-30 KT TUE AFTERNOON WITH STRONGER GUSTS IN TSTMS IF
THEY DEVELOP. PRED VFR CONDITIONS WILL RETURN WED THROUGH FRI.
&&
.MARINE...
SHORT TERM /THROUGH TONIGHT/...
AS OF 100 AM MONDAY...LATEST RAP MODEL INDICATES A SURGE WILL WORK
ITS WAY DOWN THE COAST THROUGH THE OVERNIGHT HOURS. AS A RESULT...LIGHT
SW/W WILL BECOME NORTH AND INCREASE TO 15 TO 20 KNOTS WITH A GUSTS
TO 25 KTS AS HIGH PRESSURE OVER THE GREAT LAKES MOVES SOUTHEAST
AND THE CAA SURGE WORKS DOWN THE COAST. WINDS GRADUALLY VEER NE
AND DECREASE AS THE PRES GRADIENT EASES MON AFTERNOON. SEAS BUILD
TO 5-7 FT LATE TONIGHT IN THE MODERATE NORTH FLOW THEN SLOWLY
SUBSIDE MONDAY AFTN AS WINDS BEGIN TO VEER AND DECREASE. MAIN
CHANGE TO THE FORECAST WAS TO EXTEND THE ADVISORY SOUTH DOWN TO
CAPE LOOKOUT.
LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
AS OF 3 PM SUN...UNSETTLED CONDITIONS EXPECTED THROUGH THE PERIOD.
CONDITIONS WILL QUICKLY DETERIORATE MON NIGHT INTO EARLY TUE MORNING
AS WARM FRONT AND AN AREA OF LOW PRESSURE LIFT INTO THE
AREA...FLOWING BECOMING SE AND INCREASING TO 15-25KT TUE WITH SEAS
BUILDING TO 7-12FT BY TUE EVENING. WINDS EXPECTED TO PEAK TUE
AFTERNOON AND EVENING WITH A PERIOD OF GALE FORCE CONDITIONS
POSSIBLE. A BRIEF PERIOD OF HIGH SURF CONDITIONS WILL ALSO BE
POSSIBLE GIVEN STRONG ONSHORE FLOW AND BREAKING WAVES 7-10FT. TUE
NIGHT THE SFC LOW WILL LIFT INTO THE MID-ATLANTIC WITH THE ATTENDANT
COLD FRONT MOVING THROUGH THE WATERS. GRADIENT WILL REMAIN TIGHTENED
THROUGH FRI WITH SW/W WINDS 15-25KT AND SEAS REMAINING AROUND 4-7 FT
THROUGH THU...THEN SUBSIDE TO BLO 6 FT FRI.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR AMZ152-
154.
SMALL CRAFT ADVISORY UNTIL 11 AM EST THIS MORNING FOR AMZ135-
150-156.
&&
$$
SYNOPSIS...BTC
NEAR TERM...CTC/JME
SHORT TERM...BTC
LONG TERM...SK
AVIATION...JME/SK
MARINE...CTC/BTC/JME/SK
AREA FORECAST DISCUSSION
NWS SPOKANE WA
942 PM PST Sun Feb 24 2013
.SYNOPSIS...A winter storm system will affect the Inland Northwest
tonight into Monday, with accumulating snows and breezy winds
expected over most locations. Another quick-moving, weaker system
will affect the region midweek. Warmer weather will make an
appearance late this week, with Spring-like temperatures expected.
&&
.DISCUSSION...
Little if any changes made to current forecast. Majority of
significant precipitation begins roughly near 7Z near the
cascades and more toward 9-10Z for the Spokane area per the most
recent HRRR solutions and the grids and forecast already had a
good handle on that. Other issues of note would be the increase in
post frontal winds as the surface low passing near the Southern
British Columbia border along with the cold front passage increase
the pressure gradient. Perhaps may increase wind near the
Waterville Plateau a bit more upon further scrutiny toward near
Advisory wind gusts amounts. /Pelatti
&&
.AVIATION...
06Z TAFS: A storm system will bring mostly snow as far as
precipitation goes to all TAF sites tonight and continuing into
tomorrow morning. Ceilings associated with the snow should lower
to MVFR/IFR. Wind should increase and be gusty to 30KTS and
perhaps some speed shear type low level wind shear may occur in
the vicinity of east slopes of the Cascades and into some of the
lowlands overnight into tomorrow morning as well. /Pelatti
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 31 41 26 38 28 40 / 60 100 20 0 20 30
Coeur d`Alene 31 38 27 38 26 40 / 50 100 30 10 20 40
Pullman 31 39 27 39 28 42 / 40 100 30 10 10 40
Lewiston 34 48 32 48 32 50 / 20 70 20 0 10 30
Colville 31 41 27 43 26 44 / 80 100 30 10 30 50
Sandpoint 32 37 28 37 24 37 / 60 100 60 10 20 60
Kellogg 30 34 27 36 24 39 / 40 100 80 20 20 60
Moses Lake 33 48 27 48 30 49 / 60 20 0 0 10 10
Wenatchee 31 44 28 46 31 47 / 60 20 10 0 10 10
Omak 25 38 22 37 24 42 / 80 60 0 10 40 20
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...Winter Weather Advisory from 4 AM to 10 PM PST Monday for
Central Panhandle Mountains.
Winter Weather Advisory until 10 AM PST Monday for Coeur d`Alene
Area-Idaho Palouse.
Winter Weather Advisory until 10 AM PST Monday for Northern
Panhandle.
WA...Winter Weather Advisory until 10 AM PST Monday for Spokane Area-
Washington Palouse.
Winter Weather Advisory until 10 AM PST Monday for Northeast
Mountains-Okanogan Highlands.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
320 AM CST MON FEB 25 2013
.SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT
230 AM CST MON FEB 25 2013
THE MAIN FOCUS THROUGH THE NEXT FEW DAYS IS ON THE SNOW
POTENTIAL...PARTICULARLY ON TUESDAY AS A LOW PRESSURE SYSTEM
TRACKS TO THE SOUTH OF THE REGION.
CURRENTLY TRACKING SOME SPOTTY LIGHT SNOW THAT HAS DEVELOPED ALONG
AN INVERTED SURFACE TROUGH AND AHEAD OF A MID LEVEL SHORTWAVE
TROUGH PUSHING INTO WESTERN MINNESOTA. THIS SNOW IS RUNNING INTO
AN AREA OF DRIER AIR AT THE SURFACE DUE TO A RIDGE AXIS THAT RUNS
ACROSS THE SOUTHERN GREAT LAKES TOWARD CENTRAL MINNESOTA. 25.07Z
RAP SOUNDINGS FROM ACROSS SOUTHEAST MINNESOTA INTO WESTERN
WISCONSIN SHOW A DEEPENING SATURATED LAYER THAT COINCIDES WITH THE
WEAK TO MODERATE LIFT FROM LOW LEVEL FRONTOGENESIS THIS MORNING
AND SHOULD HELP TO PROMOTE THE DEVELOPMENT OF THE LIGHT SNOW.
VISIBILITY HAS MAINLY BEEN IN THE 3-6SM RANGE ACROSS SOUTHEAST
MINNESOTA SO FAR THIS MORNING...BUT THERE HAVE BEEN TIMES WHEN IT
HAS DROPPED TO LESS THAN 2SM. REPORTS SO FAR FROM THIS AREA HAVE
BEEN THAT THERE HAS JUST BEEN A TRACE TO PERHAPS A TENTH OR TWO OF
SNOW ACCUMULATION. 25.00Z MESO-MODELS SUGGEST THAT THIS BAND WILL
LIFT TO THE NORTHEAST THIS MORNING TOWARD GREEN BAY AND GENERALLY
DISSIPATE IN COVERAGE AS THE LIFT WEAKENS. STILL KEPT SOME SMALL
CHANCES IN THROUGH 18Z WITH JUST THE TENTH OR TWO OF ACCUMULATION
EXPECTED. THE MAIN CONCERN IS JUST THE TIMING OF IT COMING IN
RIGHT BEFORE THIS MORNINGS COMMUTE WHICH COULD MAKE FOR A FEW
SLICK SPOTS IF IT CAN ACCUMULATE. THE 25.07Z RAP SOUNDINGS ALSO
INDICATE A POSSIBLE LOSS OF ICE LATER THIS MORNING...BUT THINK
THAT THE FORCING WILL HAVE CEASED AT THAT POINT AND IS LIKELY THE
REASON THE MID LEVEL SATURATION ENDS.
AS THE INVERTED SURFACE TROUGH WASHES OUT TODAY AND THE NEXT
SYSTEM TRACKS THROUGH THE OZARKS...THE SURFACE RIDGE AXIS WILL
LIFT NORTH OF THE REGION AND SHOULD KEEP ANY OF THE POTENTIAL FOG
THERE AS WELL. THE DRY LOW LEVEL AIR IN PLACE FROM THE RIDGE IS
ONE OF THE CONCERNS GOING INTO THE NEXT SYSTEM ON TUESDAY AND HOW
FAST THE COLUMN WILL BE ABLE TO SATURATE OUT.
CONFIDENCE REMAINS SOMEWHAT LOW IN HOW THE SYSTEM ON TUESDAY WILL PAN
OUT...BUT THE TREND STILL APPEARS TO BE FOR A SOUTHERN TRACK THAT
MAY KEEP MUCH OF THE FORECAST AREA ON THE DRY SIDE. THE 25.00Z NAM
IS A CONSIDERABLE OUTLIER WITH ITS TRACK TO THE NORTH AND HAS BEEN
CORRECTED WITH THE 25.06Z RUN. 25.00Z GFS/25.06Z NAM BUFKIT
SOUNDINGS SHOW A DRY LAYER BETWEEN 900MB AND 700MB THAT WILL TAKE
SOME TIME TO SATURATE OUT AS THE SYSTEM APPROACHES FROM THE
SOUTHWEST. HAVE REALLY SLOWED DOWN THE TIMING OF THE SNOW MOVING
IN ON TUESDAY FROM THE SOUTH AS THE DRY AIR APPEARS TO WIN OUT FOR
MUCH OF THE DAY. THROUGH 00Z WEDNESDAY...THE BEST CHANCES FOR ANY
SNOW APPEAR TO BE IN CLAYTON/GRANT COUNTIES...THOUGH THE ONLY
25.00Z MODEL THAT HAS ANY SNOW IN THERE BY THAT TIME IS THE GFS
WHICH IS NOTORIOUSLY HIGH ON ITS HUMIDITY AT TIMES. THUS...MORE
ADJUSTMENTS MAY BE NEEDED IN FORECAST AS CONFIDENCE INCREASES THAT
THE SNOW WILL NOT OCCUR. THIS 12Z TUESDAY THROUGH 00Z WEDNESDAY
PERIOD IS CRUCIAL BECAUSE IT IS GOING TO BE THE MAIN TIME FRAME
FOR ANY DECENT SNOWFALL ACCUMULATION. AFTER 00Z WEDNESDAY...THE
SYSTEM LOSES A LOT OF ITS DEEP/STRONG FORCING AS THE LOW FILLS
INTO THE NIGHT. FOR NOW...HAVE MAINTAINED SOME 2-4 INCH SNOW
AMOUNTS FOR CLAYTON/GRANT COUNTY WITH LESS THAN 2 INCHES NORTHWEST
OF THERE TUESDAY INTO TUESDAY NIGHT...BUT AS
MENTIONED...CONFIDENCE IN THIS OCCURRING IS FAIRLY LOW AND BASED
ON THIS WOULD NOT THINK THAT AN ADVISORY IS GOING TO BE NEEDED.
HOW LONG THE LIGHT SNOW MAY LINGER IS ALSO IN QUESTION AS 25.00Z
GFS/25.06Z NAM BUFKIT SOUNDINGS SHOW WEAK LIFT AND DIMINISHING
SATURATION OF THE COLUMN INTO WEDNESDAY NIGHT. MAINTAINED SOME
CHANCES OF SOME LIGHT SNOW WITH THE HIGHEST CHANCES ACROSS
SOUTHWEST WISCONSIN AND NORTHEAST IOWA WHERE THE CORE OF THE UPPER
LEVEL LOW WILL TRACK ACROSS. ANY SNOW AMOUNTS OVER THIS PERIOD
WOULD BE LIGHT AT LESS THAN AN INCH.
.LONG TERM...THURSDAY THROUGH SUNDAY
320 AM CST MON FEB 25 2013
AFTER THE SYSTEM MOVES OFF TO THE EAST COAST BY MID WEEK...A BROAD
RIDGE OF HIGH PRESSURE WILL EXTEND DOWN FROM NORTH CENTRAL CANADA
DOWN TO THE GULF COAST AND REMAIN ACROSS THE UPPER MISSISSIPPI
RIVER VALLEY REGION INTO NEXT WEEKEND. WHILE THE LOW TO UPPER
LEVEL FLOW WILL BE OUT OF THE NORTH...THERE IS NOT MUCH OF A COLD
SOURCE TO PULL FROM OUT OF CENTRAL CANADA...SO TEMPERATURES SHOULD
NOT TAKE MUCH OF A HIT THROUGH THE WEEK. CLEARING SKIES AND AN
INCREASING SUN ANGLE WILL HELP AS WELL TO KEEP TEMPERATURES NEAR
NORMAL.
&&
.AVIATION...THROUGH 06Z TUESDAY
1149 PM CST SUN FEB 24 2013
CLOUDS ARE NOW FIRMLY ENTRENCHED AT THE TAF SITES. A THICK UPPER
CLOUD HAS ALSO FORMED ABOVE THE LOWEST CEILING LAYER...WHICH WILL
PREVENT IFR FOG FROM FORMING THROUGH MORNING. HOWEVER...SOME MVFR
BR AND LOWER MVFR CIGS ARE EXPECTED TO FORM AS A BAND OF LIFT
ACROSS KRST BEGINS TO CAUSE SOME -SHSN AND BETTER SATURATION IN THE
BOUNDARY LAYER. CURRENT THINKING ON THE -SNSH IS THAT IT WILL BE
SPOTTY NEAR KRST UNTIL THE NEAR-DAWN HOURS MONDAY WHEN A LIGHT
SNOW PERIOD IS POSSIBLE. THIS MAY CAUSE PERIODIC IFR SHOULD THE
LIFT BE STRONG ENOUGH TO SATURATE THE LOW-LEVELS. KLSE MAY SEE A
FEW -SHSN BUT CONFIDENCE WAS NOT HIGH ENOUGH TO INCLUDE IN THE
TAF.
THIS LIFT WILL PASS OF TO THE NORTHEAST BY LATER MORNING ENDING
THE SHSN ACTIVITY...WITH IMPROVING CONDITIONS TO VFR.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
320 AM CST MON FEB 25 2013
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...BAUMGARDT
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1150 PM CST SUN FEB 24 2013
.SHORT TERM...
1008 PM CST SUN FEB 24 2013
TOUGH LITTLE FORECAST TONIGHT WITH DETAILS IN A MESSY
PATTERN. WAS WORKING TO TRY AND FIGURE OUT THE FORECAST OF THE BAND
OF WEAK ECHO FROM ROUGHLY OMAHA TO ROCHESTER MN AND ITS IMPACT
LATE TONIGHT. BIGGEST CONCERN IS A BIT OF LIGHT ACCUMULATING SNOW
AROUND COMMUTE TIME.
TWO LEVELS OF CLOUDS ARE SLOWLY WORKING INTO THE AREA FROM THE
SOUTHWEST. WEST OF THE MISS RIVER A LOWER LEVEL CLOUD DECK IS
KEEPING TEMPERATURES WARMER THAN FORECAST AND HAVE ADJUSTED THESE
AND WITH MORE CLOUD OVERNIGHT...HAVE RAISED OVERNIGHT LOWS BY
A2-3F THERE. CLEARING IN CENTRAL WI WILL CONTINUE TO PROMOTE
COOLING AND FOG IN THE RIDGE AXIS. WITH CLOUDS COMING IN
THOUGH...ANY DENSE FOG SHOULD BE SHORT LIVED SO CONTINUED THE
TREND OF NO FOG AFTER 09Z SOUTH OF I-94.
FRONTOGENETIC BAND BETWEEN NORTHERN SYSTEM AND SOUTHERN SYSTEM IS
CAUSING ENOUGH LIFT FOR THE ECHO BAND MENTIONED ABOVE FROM OMAHA
NORTHEAST. GUIDANCE HAVE MIXED REVIEWS ON THIS BAND BUT OVERALL IT
SHOULD INTENSIFY OVER IOWA AND SHIFT NORTHEAST OVERNIGHT. NEW
25.00Z NAM HAS ABOUT 0.5 INCHES ACROSS SERN MN/NERN IA BY MID-
MORNING. 24.18Z GFS AND RAP ALSO SHOW MEASURABLE SNOW. SO...HAVE
TAKEN A STEP TOWARD LIGHT SNOW MOVING IN BY SUNRISE. THEN...THE
SNOWS SHIFT NORTHEAST AND THE FORCING DOES WEAKEN.
THEREFORE...HAVE LEFT FLURRIES IN THE MORNING OVER THE NORTHWEST
FORECAST AREA. THE RAOB AT KMPX AT 00Z IS QUITE DRY...BUT IT IS
MORE MOIST FURTHER SOUTH.
SYSTEM TO THE SOUTH WILL BE VERY CLOSE WITH THE NEW 25.00Z NAM
COMING IN WITH HIGHER AMOUNTS. THE FAR SOUTH /GRANT AND FAYETTE
COUNTIES/ ARE VERY CLOSE TO A WATCH WITH SOME HIGHER WIND GUSTS
ALSO INVOLVED. WITH THE 24.18Z GFS SUGGESTING 8 INCHES AS THE
HIGH OUTLIER AS OF LATE. WILL NOT MAKE CHANGES NOW...BUT A HIGH
END ADVISORY IS A SURE BET IT APPEARS.
.LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY
306 PM CST SUN FEB 24 2013
THE LONG TERM FORECAST CONTINUES TO LOOK QUIET. GOOD MODEL AGREEMENT
CONTINUES AMONGST THE 24.12Z ECMWF/GFS/CANADIAN AND ECMWF
ENSEMBLES...WHICH SHOW RIDGING BUILDING UP OVER THE WESTERN U.S.
THROUGH SATURDAY WHILE TROUGHING HANGS IN PLACE OVER THE EASTERN
U.S.. THE FORECAST AREA IS CAUGHT IN THE MIDDLE BETWEEN THE
TWO...FAVORING A RIDGE OF HIGH PRESSURE WHICH SLOWLY BUILDS EAST
INTO THE FORECAST AREA DURING THIS PERIOD. THERE ARE INDICATIONS OF
A SHORTWAVE TROUGH DROPPING SOUTH THROUGH THE AREA ON FRIDAY...BUT
THERE ARE BOTH UNCERTAINTIES EXACTLY ON WHERE IT TRACKS AND WHETHER
IT WILL HAVE ENOUGH MOISTURE TO PRODUCE PRECIPITATION. THEREFORE...
AFTER SOME LINGERING SMALL PRECIPITATION CHANCES OVER WISCONSIN
AREAS WEDNESDAY NIGHT ASSOCIATED WITH THE SLOWLY DEPARTING AND
WEAKENING STORM TO OUR EAST...HAVE A DRY FORECAST FOR THURSDAY INTO
SATURDAY. HEADING INTO SUNDAY...A MORE POTENT SHORTWAVE TROUGH LOOKS
TO CRASH THROUGH THE WESTERN U.S. RIDGE...BUT ONLY MAKE IT INTO THE
NORTHERN ROCKIES BY 00Z MONDAY. IT SHOULD BE ENOUGH TO PUSH SOME OF
THE UPPER RIDGE EAST...ALLOWING THE SURFACE HIGH PRESSURE RIDGE TO
AT LEAST MOVE OVER IF NOT SHIFT OFF TO THE EAST FORECAST AREA.
NEEDLESS TO SAY...ANOTHER DRY DAY IS ANTICIPATED SUNDAY.
TEMPERATURES ARE A LITTLE TOUGH GIVEN A NORTHERLY FLOW PRESENT WHICH
BRINGS DOWN SOME COOLER AIR FOR MUCH OF THE PERIOD. HOWEVER...IT IS
NOT THAT COLD...NOTED BY 850MB TEMPS AT MOST DROPPING TO -8 TO -12C
BY FRIDAY. ANY SUNSHINE THAT OCCURS...WHICH MORE COULD HAPPEN IF THE
ECMWF IS RIGHT...WILL ALLOW FOR GOOD MIXING. THUS HAVE LEFT A
CONSENSUS APPROACH WHICH YIELDS HIGHS JUST SLIGHTLY BELOW NORMAL.
&&
.AVIATION...THROUGH 06Z TUESDAY
1149 PM CST SUN FEB 24 2013
CLOUDS ARE NOW FIRMLY ENTRENCHED AT THE TAF SITES. A THICK UPPER
CLOUD HAS ALSO FORMED ABOVE THE LOWEST CEILING LAYER...WHICH WILL
PREVENT IFR FOG FROM FORMING THROUGH MORNING. HOWEVER...SOME MVFR
BR AND LOWER MVFR CIGS ARE EXPECTED TO FORM AS A BAND OF LIFT
ACROSS KRST BEGINS TO CAUSE SOME -SHSN AND BETTER SATURATION IN THE
BOUNDARY LAYER. CURRENT THINKING ON THE -SNSH IS THAT IT WILL BE
SPOTTY NEAR KRST UNTIL THE NEAR-DAWN HOURS MONDAY WHEN A LIGHT
SNOW PERIOD IS POSSIBLE. THIS MAY CAUSE PERIODIC IFR SHOULD THE
LIFT BE STRONG ENOUGH TO SATURATE THE LOW-LEVELS. KLSE MAY SEE A
FEW -SHSN BUT CONFIDENCE WAS NOT HIGH ENOUGH TO INCLUDE IN THE
TAF.
THIS LIFT WILL PASS OF TO THE NORTHEAST BY LATER MORNING ENDING
THE SHSN ACTIVITY...WITH IMPROVING CONDITIONS TO VFR.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
306 PM CST SUN FEB 24 2013
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BAUMGARDT
LONG TERM...AJ
AVIATION...BAUMGARDT
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1008 PM CST SUN FEB 24 2013
.SHORT TERM...
1008 PM CST SUN FEB 24 2013
TOUGH LITTLE FORECAST TONIGHT WITH DETAILS IN A MESSY
PATTERN. WAS WORKING TO TRY AND FIGURE OUT THE FORECAST OF THE BAND
OF WEAK ECHO FROM ROUGHLY OMAHA TO ROCHESTER MN AND ITS IMPACT
LATE TONIGHT. BIGGEST CONCERN IS A BIT OF LIGHT ACCUMULATING SNOW
AROUND COMMUTE TIME.
TWO LEVELS OF CLOUDS ARE SLOWLY WORKING INTO THE AREA FROM THE
SOUTHWEST. WEST OF THE MISS RIVER A LOWER LEVEL CLOUD DECK IS
KEEPING TEMPERATURES WARMER THAN FORECAST AND HAVE ADJUSTED THESE
AND WITH MORE CLOUD OVERNIGHT...HAVE RAISED OVERNIGHT LOWS BY
A2-3F THERE. CLEARING IN CENTRAL WI WILL CONTINUE TO PROMOTE
COOLING AND FOG IN THE RIDGE AXIS. WITH CLOUDS COMING IN
THOUGH...ANY DENSE FOG SHOULD BE SHORT LIVED SO CONTINUED THE
TREND OF NO FOG AFTER 09Z SOUTH OF I-94.
FRONTOGENETIC BAND BETWEEN NORTHERN SYSTEM AND SOUTHERN SYSTEM IS
CAUSING ENOUGH LIFT FOR THE ECHO BAND MENTIONED ABOVE FROM OMAHA
NORTHEAST. GUIDANCE HAVE MIXED REVIEWS ON THIS BAND BUT OVERALL IT
SHOULD INTENSIFY OVER IOWA AND SHIFT NORTHEAST OVERNIGHT. NEW
25.00Z NAM HAS ABOUT 0.5 INCHES ACROSS SERN MN/NERN IA BY MID-
MORNING. 24.18Z GFS AND RAP ALSO SHOW MEASURABLE SNOW. SO...HAVE
TAKEN A STEP TOWARD LIGHT SNOW MOVING IN BY SUNRISE. THEN...THE
SNOWS SHIFT NORTHEAST AND THE FORCING DOES WEAKEN.
THEREFORE...HAVE LEFT FLURRIES IN THE MORNING OVER THE NORTHWEST
FORECAST AREA. THE RAOB AT KMPX AT 00Z IS QUITE DRY...BUT IT IS
MORE MOSIT FURTHER SOUTH.
SYSTEM TO THE SOUTH WILL BE VERY CLOSE WITH THE NEW 25.00Z NAM
COMING IN WITH HIGHER AMOUNTS. THE FAR SOUTH /GRANT AND FAYETTE
COUNTIES/ ARE VERY CLOSE TO A WATCH WITH SOME HIGHER WIND GUSTS
ALSO INVOLVED. WITH THE 24.18Z GFS SUGGESTING 8 INCHES AS THE
HIGH OUTLIER AS OF LATE. WILL NOT MAKE CHANGES NOW...BUT A HIGH
END ADVISORY IS A SURE BET IT APPEARS.
.LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY
306 PM CST SUN FEB 24 2013
THE LONG TERM FORECAST CONTINUES TO LOOK QUIET. GOOD MODEL AGREEMENT
CONTINUES AMONGST THE 24.12Z ECMWF/GFS/CANADIAN AND ECMWF
ENSEMBLES...WHICH SHOW RIDGING BUILDING UP OVER THE WESTERN U.S.
THROUGH SATURDAY WHILE TROUGHING HANGS IN PLACE OVER THE EASTERN
U.S.. THE FORECAST AREA IS CAUGHT IN THE MIDDLE BETWEEN THE
TWO...FAVORING A RIDGE OF HIGH PRESSURE WHICH SLOWLY BUILDS EAST
INTO THE FORECAST AREA DURING THIS PERIOD. THERE ARE INDICATIONS OF
A SHORTWAVE TROUGH DROPPING SOUTH THROUGH THE AREA ON FRIDAY...BUT
THERE ARE BOTH UNCERTAINTIES EXACTLY ON WHERE IT TRACKS AND WHETHER
IT WILL HAVE ENOUGH MOISTURE TO PRODUCE PRECIPITATION. THEREFORE...
AFTER SOME LINGERING SMALL PRECIPITATION CHANCES OVER WISCONSIN
AREAS WEDNESDAY NIGHT ASSOCIATED WITH THE SLOWLY DEPARTING AND
WEAKENING STORM TO OUR EAST...HAVE A DRY FORECAST FOR THURSDAY INTO
SATURDAY. HEADING INTO SUNDAY...A MORE POTENT SHORTWAVE TROUGH LOOKS
TO CRASH THROUGH THE WESTERN U.S. RIDGE...BUT ONLY MAKE IT INTO THE
NORTHERN ROCKIES BY 00Z MONDAY. IT SHOULD BE ENOUGH TO PUSH SOME OF
THE UPPER RIDGE EAST...ALLOWING THE SURFACE HIGH PRESSURE RIDGE TO
AT LEAST MOVE OVER IF NOT SHIFT OFF TO THE EAST FORECAST AREA.
NEEDLESS TO SAY...ANOTHER DRY DAY IS ANTICIPATED SUNDAY.
TEMPERATURES ARE A LITTLE TOUGH GIVEN A NORTHERLY FLOW PRESENT WHICH
BRINGS DOWN SOME COOLER AIR FOR MUCH OF THE PERIOD. HOWEVER...IT IS
NOT THAT COLD...NOTED BY 850MB TEMPS AT MOST DROPPING TO -8 TO -12C
BY FRIDAY. ANY SUNSHINE THAT OCCURS...WHICH MORE COULD HAPPEN IF THE
ECMWF IS RIGHT...WILL ALLOW FOR GOOD MIXING. THUS HAVE LEFT A
CONSENSUS APPROACH WHICH YIELDS HIGHS JUST SLIGHTLY BELOW NORMAL.
&&
.AVIATION...TONIGHT AND TUESDAY
626 PM CST SUN FEB 24 2013
A CHALLENGING CLOUD AND FOG FORECAST OVERNIGHT INTO MONDAY. AT
00Z...A NORTHEAST-SOUTHWEST ORIENTED MVFR STRATUS DECK IS LOCATED
FROM SERN MN TO OMAHA NEBRASKA. KRST NOW IS IN THIS STRATUS...
WHICH IS SPREADING SLOWLY NORTHEAST. THIS WILL WORK INTO KLSE
SHORTLY. SOME HIGHER CLOUD OVER THE TOP OF THE MVFR STRATUS IS ALSO
SPREADING NORTHEAST FROM THE BIGGER STORM SYSTEM OVER THE SOUTHERN
PLAINS. WITH LIGHT WINDS AND SURFACE RIDGING IN PLACE AND LIGHT
WINDS...AS OVERNIGHT TEMPERATURES COOL...THE STRATUS IS EXPECTED
TO SLOWLY LOWER AS THE BOUNDARY LAYER SATURATES.
AT THIS TIME THE NEW TAFS HAVE SLOWED THE DETERIORATION TO IFR AT
KRST TO AFTER 06Z. BUT HAVE ALSO LOWERED THE VSBYS TO 1 MILE BY
MORNING...AND IT COULD BE LIFR CIG/VSBY SHOULD THE CONDITIONS COME
TOGETHER RIGHT AND THE SECOND LAYER OF CLOUD ABOVE THE STRATUS IS
MINIMAL.
THOSE WITH FLYING INTERESTS IN THE MORNING SHOULD AT LEAST PLAN ON
LOWER MVFR...POSSIBLY DOWN TO LIFR.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
306 PM CST SUN FEB 24 2013
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BAUMGARDT
LONG TERM...AJ
AVIATION...BAUMGARDT
AREA FORECAST DISCUSSION
NWS TOPEKA KS
509 AM CST MON FEB 25 2013
.DISCUSSION...
SEE PREV DISCUSSION.
&&
.AVIATION...
THE 09Z RAP AND 06Z NAM HAVE BEEN SHOWING DRY LOW LEVEL AIR
ENTRAINING FROM THE NORTHEAST THROUGH MUCH OF THE DAY TODAY.
ADDITIONALLY THE GFS AND NAM DO NOT BRING THE TROWAL WITH THE
HEAVIEST SNOWFALL INTO THE TERMINALS UNTIL AFTER 00Z. THEREFORE
EXPECT VFR CONDITIONS TO PREVAIL TODAY AND HAVE PUSHED BACK THE IFR
CIGS AND VSBY WITH -SN UNTIL THIS EVENING.
WOLTERS
&&
.PREV DISCUSSION... /402 AM CST MON FEB 25 2013/
FORECAST IS STILL ON TRACK FOR A POTENT WINTER SYSTEM...EXPECTED TO
AFFECT THE AREA WITH MODERATE TO HEAVY SNOW AND STRONG WINDS MONDAY
THROUGH INTO TUESDAY.
A VERY VIGOROUS MID LEVEL TROUGH IS CURRENTLY EVIDENT ON WATER VAPOR
IMAGERY AS IT SPINS ACROSS EASTERN NEW MEXICO INTO FAR WESTERN
TEXAS. THE TRACK OF THIS WAVE WILL LIKELY RUN ALONG THE RED RIVER TO
NEAR DFW BEFORE NEGATIVELY TILTING AND EJECTING NORTHEASTWARD
THROUGH OKLAHOMA INTO NW ARKANSAS. RADAR TRENDS SHOW INCREASING
REFLECTIVITY RETURNS FROM ACROSS WESTERN OKLAHOMA AND
TEXAS...INDICATING MORE INTENSE PRECIP WITH ACCOMPANYING THUNDER.
ALSO EVIDENT ON RADAR IS A DEFORMATION BAND TAKING SHAPE ACROSS
SOUTH CENTRAL KANSAS...EXTENDING NORTHEASTWARD INTO NORTH CENTRAL
AND NORTHEAST KANSAS. THIS DEFORMATION BAND WILL KICK OFF THE
PRECIPITATION EXPECTED FROM THIS WINTER STORM ACROSS THE REGION.
SURFACE OBSERVATIONS INDICATE ABOVE FREEZING TEMPS IN NORTHEAST AND
EAST CENTRAL KANSAS...AND AT OR BELOW FREEZING IN CENTRAL AND NORTH
CENTRAL KANSAS. EXPECT THE LIGHT PRECIP TO FALL AS LIGHT SNOW...OR
PERHAPS SOME LIGHT FREEZING RAIN...WITH MINOR TO NO ICE
ACCUMULATION.
THE AFOREMENTIONED MID LEVEL WAVE IS EXPECTED TO EJECT
NORTH/NORTHEAST INTO NORTHWEST ARKANSAS LATER TONIGHT TAKING WITH IT
A STRONG PV ANOMALY. THE PV ANOMALY WILL LIKELY TRAVERSE JUST SOUTH
OF THE FORECAST AREA. WITH THE LOW AND MID LEVEL TROUGHS EXPECTED TO
PASS THROUGH JUST SOUTH OF THE FORECAST AREA COLDER AIR WILL BE
ALLOWED TO FILTER IN...ALLOWING FOR A QUICKER COOLING OF THE THERMAL
PROFILE THROUGHOUT THE DAY. AREAS ALONG AND NORTH/NORTHWEST OF THE
KANSAS TURNPIKE WILL LIKELY GO STRAIGHT TO SNOW AS THE COLUMN
SATURATES...WITH AREAS SOUTH/SOUTHEAST OF THE TURNPIKE LIKELY
HOLDING ONTO A PERIOD OF LIGHT RAIN/FREEZING RAIN THROUGH THE
DAYTIME HOURS ON MONDAY. WITH SURFACE TEMPS HAVING A TOUGH TIME
GETTING BELOW FREEZING WHERE LIGHT RAIN IS EXPECTED ITS UNLIKELY AT
THIS TIME FOR FREEZING RAIN TO PRODUCE ANY KIND OF ACCUMULATION. BY
MID DAY FORECAST SOUNDINGS VIRTUALLY ACROSS THE ENTIRE AREA INDICATE
A GRADUAL MOISTENING OF THE THERMAL COLUMN AS IT COOLS. ISENTROPIC
SURFACES ALONG THE 290 TO 305 K SURFACES INDICATE THAT THE EASTERN
HALF OF THE CWA...TOWARD TOP/LWC/MCI WILL TAKE A WHILE TO OVERCOME
THE DRY AIR...AS CONDENSATION PRESSURE DEFICITS REMAIN AROUND 50 TO
100 MB UNTIL ABOUT 21Z. RIGHT NOW PEGGING BETWEEN 21Z AND 00Z AS
A LIKELY START TIME FOR LIGHT SNOW TO COMMENCE ALONG AND SOUTH OF
INTERSTATE 70. BY 00Z GFS/NAM INDICATE A VERY IMPRESSIVE TROWAL
SIGNATURE WITH CONDENSATION PRESSURE DEFICITS NEAR 0 ALONG THE
PREVIOUSLY MENTIONED ISENTROPIC SURFACES INDICATING STRONG
ISENTROPIC ASCENT AND SATURATION. AROUND 00Z NAM/GFS ALSO SHOW OFF
A VERY IMPRESSIVE AND PRONOUNCED PERIOD OF LOW AND MID LEVEL
FRONTOGENESIS...MAINLY SOUTHEAST OF A LINE BETWEEN HIAWATHA AND
COUNCIL GROVE. DURING THIS TIME OF ENHANCED LOW/MID LEVEL
FRONTOGENESIS THE COLUMN BECOMES SATURATED THROUGH THE DENDRITIC
GROWTH ZONE...INDICATING EFFICIENT SNOWFALL IN FAR NE AND EC
KANSAS. CONCURRENT WITH THE STRONG FRONTOGENESIS IS AN AREA OF
WEAKENED STABILITY...INDICATED BY A RIBBON OF EPV AROUND -.5 TO
-1.0 PVU...JUST ABOVE THE MAIN FRONTOGENESIS BULLS EYE. GIVEN THIS
PERIOD OF POTENTIAL CONVECTIVE DEVELOPMENT (00Z TO 09Z TUESDAY)
THE POTENTIAL EXISTS FOR HEAVY SNOWFALL IN EAST CENTRAL KANSAS
WITH 1 TO POTENTIALLY 3 INCH PER HOUR RATES. BY 12Z TUESDAY THE
FRONTOGENESIS AND EPV INFLUENCES MOVE OFF TO THE EAST...AND LIGHT
SNOW MAY PERSIST WITHIN THE DEPARTING TROWAL THROUGH 12Z-18Z
TUESDAY.
REGARDING SNOW AMOUNTS...THE FORECAST REMAINS VERY TRICKY AS THERE
WILL LIKELY BE A PRETTY TIGHT GRADIENT BETWEEN THE HIGHEST AMOUNTS
IN EC KANSAS AND THE NORTHERN/WESTERN PERIPHERY OF THE SNOW
ACCUMULATIONS. ALTHOUGH MODEL CONSENSUS ON GENERAL TRACK OF THE
SYSTEM REMAINS PRETTY DECENT THE SLIGHTEST SHIFT IN ANY DIRECTION
WOULD BRING UNEXPECTED TOTALS TO AREAS ALONG THE PERIPHERY OF THE
SNOW SWATH. OBTAINED SNOW AMOUNTS FOR THIS FORECAST BY TAKING A
GENERAL CONSENSUS OF MODEL QPF AND TONING IT BACK TO ABOUT 75
PERCENT OF ITS OUTPUT. WHEN MULTIPLIED BY SNOW RATIOS RANGING FROM
12-15:1 THROUGHOUT THE EVENT THE FINAL SNOW FALL FORECAST FOR THIS
EVENT MATERIALIZED. GENERALLY EXPECT A 10-13 INCH SWATH TO FORM
ACROSS EAST CENTRAL KANSAS...DECREASING RATHER RAPIDLY TO THE NORTH
AND WEST...TO AROUND 10 INCHES IN TOP/LWC...AND 7-9 INCHES IN
MHK...ABILENE...AND HIAWATHA...AND 3-5 INCHES ACROSS NORTH CENTRAL
KANSAS. WAS TEMPTED TO LOWER AMOUNTS EVEN MORE IN THE EASTERN
ZONES...CONSIDERING THE POSSIBILITY OF THE SYSTEM CREEPING EVEN
FURTHER SOUTH/EAST...BUT 00Z 4KM WRF INDICATED THAT THE TROWAL
PORTION OF THE SYSTEM MAY RESIDE OVER THE AREA...PRODUCING LIGHT TO
MODERATE SNOW THROUGH POTENTIALLY TUESDAY NIGHT...BRINGING EVEN MORE
ACCUMULATION.
A TIGHTENING SURFACE LOW PRESSURE GRADIENT WILL CAUSE WINDS OUT OF
THE NORTH/NORTHEAST TO INCREASE THROUGHOUT THE DAY...AND INTO
TONIGHT...PRODUCING STRONG WINDS APPROACHING 20 TO 25 MPH WITH GUSTS
NEARING 35 MPH. MODEL SOUNDINGS INDICATE STRONG LOW LEVEL WINDS
APPROACHING 50 KTS...BUT WITH LOW LEVEL LAPSE RATES NOT BEING
EXTREMELY STEEP DO NOT EXPECT ENOUGH MIXING TO ALLOW THOSE WINDS TO
REACH THE SURFACE...THEREFORE TRUE BLIZZARD CONDITIONS ARE NOT
EXPECTED...HOWEVER THE STRONG WINDS CONCURRENT WITH THE HEAVIEST
SNOW WILL LIKELY BRING A PERIOD OF NEAR WHITE OUT CONDITIONS BETWEEN
00Z AND 012Z TUESDAY MORNING.
AS A RESULT OF THIS FORECAST...WILL LEAVE THE
HEADLINES ALONE AND LET THE UPCOMING DAY SHIFT ASSESS THE SYSTEM AND
MAKE THE DECISION TO TWEAK THE WARNING/ADVISORY AREA.
MID RANGE TO EXTENDED FORECAST (WEDNESDAY THROUGH SUNDAY)...
COLD AIR WILL LIKELY STAY IN PLACE THROUGH THE REST OF THE FORECAST
PERIOD...AS A BROAD SURFACE HIGH SLIDES INTO PLACE. ANOTHER WEAK
TROUGH WILL COME THROUGH THE AREA ON WEDNESDAY AND MAY SQUEEZE OUT A
LITTLE BIT OF MOISTURE TO PRODUCE SOME VERY LIGHT SNOW FALL WITH
PERHAPS ANOTHER FEW TENTHS OF AN INCH OF ACCUMULATION. AFTER
WEDNESDAY THE FORECAST LOOKS DRY WITH COOL TEMPERATURES IN THE MID
30S TO LOWER 40S REMAIN THROUGH THE WEEK/WEEKEND.
JL
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING FROM 6 AM MONDAY TO NOON CST TUESDAY FOR
KSZ012-023-024-026-038>040-054>056-058-059.
WINTER WEATHER ADVISORY UNTIL NOON CST TUESDAY FOR KSZ008-009-
020.
WINTER STORM WARNING UNTIL NOON CST TUESDAY FOR KSZ021-022-
034>037.
WINTER WEATHER ADVISORY FROM 6 AM MONDAY TO NOON CST TUESDAY FOR
KSZ010-011.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
623 AM EST MON FEB 25 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 337 AM EST MON FEB 25 2013
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW SPLIT FLOW
DOMINATING THE FLOW OVER NAMERICA. RDG IN THE NRN BRANCH IS PRESENT
FM JAMES BAY INTO THE UPR GRT LKS TO THE W OF DEPARTING CLOSED LO IN
SE CANADA/NEW ENGLAND...AND A SFC HI PRES RDG EXTENDS FM NE ONTARIO
THRU ECENTRAL UPR MI INTO THE UPR MIDWEST. WITH DRY AIR AOA H8 AS
SHOWN ON 00Z APX/GRB RAOBS AND LARGER SCALE SUBSIDENCE UNDER THE
RDG...THERE IS NO PCPN IN THE AREA. EVEN LES IS ABSENT WITH LLVL
ACYC FLOW AND H85 TEMPS -6C AT INL AND GRB. DESPITE PASSAGE OF SFC
RDG AXIS...QUITE A BIT OF LO CLD LINGERS WITH SOME MSTR/RELATIVELY
HI SFC DEWPTS TRAPPED BLO SUBSIDENCE INVRN H825-875 SHOWN ON THE 00Z
APX/GRB RAOBS. SOME CLRG HAS OCCURRED OVER THE W AND NEAR THE WI
BORDER INTO NE MN/NRN WI...WHERE SOME LLVL DRY AIR SHOWN ON THE 00Z
GRB/MPX RAOBS HAS SHIFTED TO THE N. WHERE SKIES HAVE CLRD...TEMPS
FELL OFF SHARPLY IN THE PRESENCE OF NEAR CALM WINDS. SOME PATCHY
FOG/ST HAS ALSO DVLPD...SO THE CLRG HOLES ARE IN SOME CASES SHORT
LIVED. ALTHOUGH THERE ARE MORE HOLES IN THE LO CLDS OVER FAR NRN
WI/NE MN...MORE LO/MID CLDS ARE STREAMING NEWD INTO CNTRL MN/WI IN
THE LLVL SW FLOW BTWN RDG AXIS OVER UPR MI AND LO PRES TROF
EXTENDING FM LK WINNIPEG INTO THE NRN PLAINS ASSOCIATED WITH PAIR OF
NRN BRANCH DISTURBANCES. A POTENT DISTURBANCE IN THE THE SRN BRANCH
IS PRESENT OVER THE SRN ROCKIES.
MAIN FCST CONCERNS IN THE SHORT TERM ARE TRICKY CLD TRENDS/IMPACT ON
TEMPS.
DESPITE SOME DIURNAL HEATING FM INCRSG SUN ANGLE AND SW FLOW ON THE
BACK SIDE OF HI PRES THAT WL ELIMINATE ANY LK SUP INFLUENCE AND
ADVECT SOME DRIER AIR THAT HAS CAUSED CLRG OVER NW WI...RECENT
TRENDS INDICATE LO CLDS MIGHT PROVE QUITE RESILIENT OVER THE CWA
WITH MORE MORE LO CLDS TENDING TO FORM OVER NRN WI. THE WINDOW FOR
CLRG WL BE RELATIVELY SHORT AS WELL BECAUSE BOTH 00Z NAM/GFS
INDICATE CLDS NOW STREAMING NEWD TOWARD CENTRAL WI AHEAD OF PAIR OF
SLOWLY APRCHG NRN BRANCH DISTURBANCES WL ARRIVE AT THE WI BORDER
LATER THIS MRNG. INCLUDED A MENTION OF FLURRIES OVER THE SCENTRAL
THIS AFTN WITH SOMEWHAT DEEPER MSTR UNDER AREA OF WEAK DEEP LYR
QVECTOR CNVGC. WITH ABUNDANT CLD COVER MORE LIKELY...WL TEND TOWARD
THE LOWER END OF GUIDANCE FOR MAX TEMPS...WHICH IS IN GOOD AGREEMENT
WITH GOING FCST. EXPECT THE HIER MAX TEMPS OVER THE NCENTRAL FM
BARAGA-MQT WHERE LLVL SSW FLOW DOWNSLOPES.
TNGT...AS PAIR OF NRN BRANCH SHRTWVS SHIFT E INTO THE UPR LKS...
GUIDANCE SHOWS THESE DISTURBANCES FADING UNDER LARGER SCALE HGT
RISES ASSOCIATED WITH BLDG UPR RDG ON NRN FLANK OF STRONGER SRN
BRANCH DISTURBANCE MOVING INTO THE MID-MS RIVER VALLEY. ALTHOUGH
LLVL FLOW TENDS ACYC...WINDS ARE FCST TO BE LGT. SO RATHER MOIST
LLVLS WL BE LINGERING IN THE ABSENCE OF SGNFT LLVL DRYING. THE
QUESTION IS WHETHER LARGER SCALE SUBSIDENCE WL RESULT IN THE BREAK
UP OF THIS LO CLD. IN THE ABSENCE OF SGNFT LLVL DRYING AND IN THE
PRESENCE OF DIURNAL COOLING...SUSPECT THE RESULT WL BE LINGERING LO
CLDS THRU THE NGT WITH SUBSIDENCE STRENGTHENING THE INVRN THAT TRAPS
THIS MSTR. CONSIDERING THE UNCERTAINTY...MADE FEW CHGS TO GOING MIN
TEMPS FCST. IF THE LO CLDS ARE MORE PERSISTENT...FCST MIN TEMPS IN
THE UPR TEENS/LO 20S WL HAVE TO BE RAISED.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 337 AM EST MON FEB 25 2013
UPPER MICHIGAN LOOK TO BE TAKING A BREAK FROM THE MODERATE TO HEAVY
SNOW THAT HAS BEEN COMMON PLACE OVER THE PAST WEEK OR SO.
THE CURRENT 500MB LOW SWINGING ACROSS NORTHERN TEXAS THIS MORNING
SHOULD BE OVER NORTHERN ARKANSAS/SOUTHERN MISSOURI BY 12Z
TUESDAY...WITH THE RIDGE EXTENDING FROM THE ATLANTIC BACK THROUGH
UPPER MICHIGAN/LAKE SUPERIOR/NORTHERN MINNESOTA.
THE 500MB RIDGE WILL BE QUICKLY PUSHED NORTH OF THE AREA DURING THE
DAY TUESDAY...WITH THE THEN NEARLY STACKED SFC-500MB SHOULD BE ABLE
TO LIFT TO SOUTHERN ILLINOIS/INDIANA. E-ENE WINDS WILL BE ON THE
INCREASE ACROSS UPPER MICHIGAN...AND IN PARTICULAR ALONG LAKE
MICHIGAN. WITH SURFACE TEMPERATURES IN THE LOW 30S...AND 850MB TEMPS
HOVERING AROUND -3C NO LAKE EFFECT SNOW IS EXPECTED. IN FACT...DRY
WEATHER SHOULD BE THE RULE THROUGH TUESDAY EVENING.
THE 25/00Z NAM IS A STRONGER FAR NORTHERN OUTLIER WITH THE 500MB
LOW...BRINGING THE 500MB LOW OVER CENTRAL LOWER MI BY 18Z WEDNESDAY.
THE CONSENSUS OF THE GFS/ECMWF/CANADIAN HAS THE FEATURE SOUTH OF
DETROIT... NORTHERN OHIO...OR ACROSS NORTHWESTERN PENNSYLVANIA. THE
DIVERGENCE OF THE NAM SOLUTION IS MOST DRAMATIC AFTER 00Z
WEDNESDAY...AND WILL THEREFORE NOT BE UTILIZED IN OUR ONGOING
FORECAST BEYOND THAT POINT. TO A LESSER EXTENT THE CANADIAN BRIDGES
THE GAP BETWEEN THE FASTER GFS/ECMWF AND THE NORTHWESTERLY NAM...BUT
ENDS UP RUNNING APPROXIMATELY 12HRS BEHIND THE ECMWF BY THURSDAY /AT
500MB ACROSS NEW YORK AND THE NEW ENGLAND STATES. MAY NEED TO ADD
FLURRIES FOR UPSLOPE AREAS OF NORTH CENTRAL UPPER MICHIGAN NEAR LAKE
SUPERIOR LATE WEDNESDAY AFTERNOON ON.
EXPECT A SHORTWAVE TO SWING ACROSS ONTARIO WEDNESDAY NIGHT INTO
THURSDAY...BUT HAVE LITTLE INFLUENCE ON OUR WEATHER OTHER THAN
KEEPING CLOUDS OVERHEAD. 850MB TEMPS WILL BE ABLE TO DROP TO AROUND
-8C THURSDAY AS COOLER AIR PUSHES IN BEHIND THE MAIN LOW. WITH N-NNE
WINDS OFF LAKE SUPERIOR THERE WILL BE AN INCREASED CHANCE OF LIGHT
LAKE EFFECT SNOW SHOWERS...WITH A SLIGHT INCREASE IN LOW LEVEL
MOISTURE...DESPITE A STRONG INVERSION NOTED OFF THE GFS HOVERING
NEAR 850MB. THE DGZ LOOKS TO REBOUND...ALTHOUGH THIN /ABOUT 50MB
THICK/ LATE WEDNESDAY NIGHT THROUGH SATURDAY MORNING.
ANOTHER 500MB RIDGE WILL BE ABLE TO PUSH ACROSS THE UPPER GREAT
LAKES THURSDAY THROUGH MUCH OF FRIDAY. EXPECT COOLER AIR TO FILTER
IN AGAIN FRIDAY NIGHT...AND TAKE HOLD OF THE UPPER GREAT LAKES BY
SUNDAY AS 850MB TEMPS FALL FROM AROUND -10C TO -13 OR -14C. WIND
DIRECTION DOES NOT CHANGE MUCH DURING THIS TIME...WITH FAIRLY STEADY
N-NE WINDS SLIDING IN OFF LAKE SUPERIOR. AS A RESULT...IT WILL BE
DIFFICULT TO TAKE OUT THE MENTION OF LIGHT SNOW SHOWERS NEAR LAKE
SUPERIOR /EVEN IF IT IS JUST A SLIGHT CHANCE/...DESPITE THE STRONG
SURFACE HIGH STRETCHING FROM NORTHERN HUDSON BAY THROUGH ONTARIO AND
PORTIONS OF LAKE SUPERIOR THURSDAY NIGHT THROUGH SUNDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 620 AM EST MON FEB 25 2013
EXPECT VFR CONDITIONS TO PREDOMINATE TODAY WITH DAYTIME HEATING AND
ARRIVAL OF LLVL DRY AIR SHOWN ON THE 00Z GRB/MPX RAOBS IN GENERAL SW
FLOW. THE ONLY EXCEPTION MAY BE SOME FOG AT SAW EARLY UNDER SMALL
AREA OF MOCLR SKIES. CIGS MAY DIP INTO THE MVFR RANGE FOR A TIME
TNGT WITH ARRIVAL OF A BIT MORE LLVL MSTR IN THE PRESENCE OF DIURNAL
COOLING.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 337 AM EST MON FEB 25 2013
A RIDGE OF HIGH PRESSURE JUST EAST OF LAKE SUPERIOR WILL REMAIN OVER
THE UPPER GREAT LAKES THROUGH TONIGHT. EXPECT LOW PRESSURE OVER THE
SOUTHERN PLAINS TO TRACK NORTHEAST ACROSS THE MID MISSISSIPPI VALLEY
ON TUESDAY...BEFORE STALLING OVER THE LOWER GREAT LAKES ON
WEDNESDAY. A PROLONGED PERIOD OF N TO NE WINDS CAN BE
EXPECTED...WITH WINDS OF 15 TO 30KTS TUESDAY INTO FRIDAY. A FEW GALE
FORCE GUSTS TO 35 KNOTS WILL BE POSSIBLE THURSDAY OVER MAINLY
CENTRAL LAKE SUPERIOR. THE LOW WILL THEN MOVE EAST THURSDAY THROUGH
FRIDAY AS HIGH PRESSURE OF NOSES SOUTHWARD INTO NORTHERN
ONTARIO...WITH LIGHTER WINDS TAKING HOLD.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...KF
AVIATION...KC
MARINE...KF
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1056 AM EST MON FEB 25 2013
.SYNOPSIS...
LAKE EFFECT CLOUDS AND SCATTERED FLURRIES THIS MORNING...MAINLY IN
CENTRAL NEW YORK...WILL YIELD TO BUILDING HIGH PRESSURE THIS
AFTERNOON. THIS WILL HELP BREAK UP THE CLOUDS LATER TODAY...AND
KEEP THINGS DRY AND QUIET TONIGHT THROUGH MOST OF TUESDAY.
HOWEVER...A MIX OF WINTRY PRECIPITATION IS LIKELY LATE TUESDAY
THROUGH EARLY WEDNESDAY AS LOW PRESSURE MOVES TOWARDS THE REGION
FROM THE OHIO VALLEY.
&&
.NEAR TERM /THROUGH TONIGHT/...
1030 AM UPDATE... VSBL SAT ANIMATION INDICATES THAT CLDS ARE
HANGING TOUGH LATE THIS MRNG ACRS CNY/PTNS OF NE PA. THE LATEST
HI-RES NWP GUIDANCE STILL INDICATES THAT SOME DRYING WILL TAKE
PLACE DURG THE COURSE OF THE AFTN...SPCLY FROM THE TWIN TIERS SWD.
WE BLENDED IN THE LATEST RUC13 DATA...WHICH SEEMS TO HAVE A GOOD
HANDLE ON THE CURRENT EVOLUTION. ANY LINGERING FLRYS SHOULD BE
GONE BY 18-19Z.
BASED ON THE 12Z RAOBS AND WEAK ANTICIPATED THERMAL ADVECTION THIS
AFTN...OUR PRESENT HIGH TEMP FCST LOOKS GOOD...AND WAS ONLY
TWEAKED VERY SLIGHTLY.
PREV DISC... 630 AM UPDATE... GRIDS TWEAKED AS PER CURRENT
OBS...AND TO LINGER CLOUD COVER A BIT LONGER INTO THE AFTERNOON.
FORECAST GENERALLY ON TRACK...WITH ONLY SCATTERED FLURRIES
REMAINING DOWNWIND OF LAKE ONTARIO.
EARLIER DISCUSSION... ATMOSPHERIC COLUMN AS A WHOLE IS DRYING OUT...YET
MOISTURE REMAINS TRAPPED IN THE LOWEST FEW THOUSAND FEET AGL UNDER
A WEAK INVERSION. 850MB TEMPERATURES ARE ABOUT 9 OR 10 BELOW ZERO
CELSIUS...BARELY ENOUGH FOR THE WEAK LAKE RESPONSE OF SCATTERED
SNOW SHOWERS CURRENTLY DOWNWIND OF LAKE ONTARIO. WARM AIR
ADVECTION ALOFT WILL GRADUALLY RAISE 850MB TEMPERATURES HEADING
INTO THE DAY WHICH WILL ALLOW SNOW SHOWERS TO TAPER OFF TO A FEW
FLURRIES BEFORE ENDING. HOWEVER...STRATOCUMULUS WILL BE A BIT MORE
STUBBORN...ESPECIALLY CENTRAL NY. OVERALL...SUNSHINE WILL INCREASE
THROUGH THE DAY BUT WILL TAKE LONGER IN SOME PLACES THAN
OTHERS...AND HIGHS WILL BE RIGHT AROUND CLIMATOLOGICAL AVERAGES.
HIGH PRESSURE IN CHARGE TONIGHT FOR QUIET AND MOSTLY CLEAR
CONDITIONS. THE GOOD RADIATIONAL COOLING SET UP WILL YIELD MAINLY
LOWER 20S FOR LOWS...THOUGH SOME TEENS FOR THE MORE TYPICALLY
PRONE COLD AIR DRAINAGE VALLEYS. IN MANY CASES...AT OR SLIGHTLY
BELOW COLDEST MODEL GUIDANCE.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
500 AM UPDATE...
TUESDAY....FAIRLY GOOD AGREEMENT AMONGST THE MODELS WITH REGARDS
TO SYNOPTIC FEATURES WITH A DOMINANT SURFACE LOW AROUND 995 MB
TRACKING THROUGH CENTRAL INDIANA WITH A NEW LOW FORMING OVER NORTH
CENTRAL NC BY 0Z WEDNESDAY. THIS IS THE EASIEST PART OF THE
FORECAST WITH THICKENING CLOUDS AND PRECIP HOLDING OFF UNTIL LATE
IN THE DAY. LOOKING FOR ARRIVAL OF PRECIP TOWARD 23Z FAR SOUTH AND
WEST. MODEL PROFILES SHOW WARM SURFACE TEMPS SO INITIAL SHOT OF
PRECIP COULD BE IN THE FORM OF SNOW...SLEET OR PLAIN RAIN.
TUESDAY NIGHT...UNCERTAINTY IS THE KEY WORD FOR THIS PART OF THE
FORECAST. DESPITE GOOD MODEL AGREEMENT WITH THE SYNOPTIC
PLAYERS...SUBTLE DIFFERENCES IN TEMP PROFILES GIVE US THE WHOLE
RANGE OF P-TYPE POSSIBILITIES DURING THE NIGHT. IF THAT WERE NOT
ENOUGH QPF AMOUNTS ARE ALSO HIGHER VARIABLE. WILL TACKLE EACH
ISSUE SEPARATELY FOR NOW.
P TYPE...THE EURO REMAINS THE COLDEST OF ALL MODELS SHOWING A
MOSTLY SNOW EVENT FOR MOST OF THE CWA UNTIL CLOSER TO DAYBREAK
WHEN WARMER AIR AROUND 850 MB MAKES ITS WAY INTO THE POCONOS.
MEANWHILE THE GFS AND NAM ARE FAIRLY SIMILAR IN THAT THEY SHOW A
TONGUE OF WARMER AIR AROUND 850 MB MOVE IN. THAT WOULD IMPLY ANY
SNOW WOULD EVENTUALLY MIX WITH SLEET/FREEZING RAIN AND PLAIN
RAIN. A FEW ITEMS THAT WE WILL BE WATCHING. THIS LAYER OF WARMER
AIR ALOFT MAY BE ABLE TO BE OVERCOME FOR A PERIOD DURING THE NIGHT
WHEN LIFT IS MAXIMIZED AND DYNAMIC COOLING ALLOWS FOR A SWITCH
OVER TO ALL SNOW. WITH TEMP PROFILES SO CLOSE..THIS MAY BE JUST
ENOUGH...ESPECIALLY OVER THE HIGHER TERRAIN OF THE CATSKILLS AND
WESTERN SOUTHERN TIER FOR A PERIOD OF HEAVIER SNOW. HOWEVER...IF THE NAM
AND GFS ARE CORRECT WITH THIS WARMER LAYER ALOFT...FREEZING RAIN
POTENTIAL WILL HAVE TO BE WATCHED CAREFULLY. MOST MODEL SOUNDINGS
SHOW SURFACE TEMPS NEAR OR BELOW FREEZING FROM ABOUT 04Z THROUGH
12Z...WITH MODEL QPFS AROUND A HALF OF AN INCH. CONFIDENCE HOWEVER
IN THIS ICE POTENTIAL IS LOW GIVEN THE MODEL UNCERTAINTY WITH
P-TYPE. IN ADDITION THOSE MODELS THAT SUGGEST THE WARMER LAYER
ALOFT...ALSO SHOW A FAIRLY DEEP LAYER OF COLDER AIR BELOW THIS WARM
NOSE WHICH WOULD SUGGEST PROLONGED SLEET VERSUS FREEZING RAIN. IF
THE FREEZING RAIN DOES PAN OUT...THE POSITION OF THE SURFACE HIGH
OVER NOVA SCOTIA WOULD GIVE US MORE OF AN EASTERLY COMPONENT TO
THE SURFACE WIND WHICH MAY NOT LOCK IN THE COLD AIR AS MUCH FOR
THE MAJORITY OF THE CWA...ASIDE FROM THE MOHAWK VALLEY WHERE IT IS
IDEAL. WITH SO MUCH UNCERTAINTY PLAYED THE GRIDS TO SHOW THIS.
PLAYED A WINTRY MIX FOR MOST OF THE AREA THROUGH THE NIGHT. BOTH
THE EURO/NAM/AND GFS DO SHOW WARMER AIR MOVING INTO NEPA SO HERE I
REMOVED THE MENTION OF SNOW OR SLEET IN THE WYOMING VALLEY TOWARD
12Z WITH ICE REMAINING IN THE POCONOS. WOULD LOVE TO BE MORE
SPECIFIC BUT SOMETIMES WE JUST DON`T KNOW THIS FAR OUT YET AND DO
NOT WANT TO CONVEY THAT WE KNOW THE EXACT P-TYPES THAT WILL FALL.
QPF...THE NAM APPEARS TO BE WAY OVERDONE WITH QPF WITH VALUES OF
BETWEEN .75" AND AN INCH BY 12Z WEDNESDAY. THE EURO IS ABOUT HALF
THAT OR AROUND A HALF OF AN INCH...WITH THE SREFS AND GFS IN THE
MIDDLE (.50-.75). PER COORDINATION WITH THE OTHER OFFICES DECIDED
TO HOLD OFF ON ANY WATCHES WITH TOO MUCH UNCERTAINTY REGARDING
P-TYPE.
WEDNESDAY....SURFACE COLD AIR MAY REMAIN ACROSS THE MOHAWK VALLEY
AND PARTS OF SULLIVAN COUNTY WITH THE EASTERLY FLOW...OTHERWISE
WARM BOUNDARY LAYER TEMPS SUPPORT A CHANGE TO MOSTLY RAIN DURING
THE DAY. TOWARD 0Z AS COLDER AIR MOVES IN FROM THE WEST SOME WET
SNOW IS POSSIBLE. STILL SOME UNCERTAINTY HERE HOWEVER GIVEN THE
EURO IS MUCH COLDER AND WOULD SUPPORT SNOW THROUGHOUT MOST OF THE DAY.
WILL STICK WITH CONTINUITY FROM THE PREVIOUS FORECAST AS IT IS
SUPPORTED BY THE GFS AND NAM...ALONG WITH MAIN SURFACE LOW TRACK
BEING TO OUR WEST AND NOT A FAVORABLE POSITION OF THE SURFACE
HIGH FOR ALL SNOW.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
130 PM UPDATE...
AS FRONT MVS THRU ON WEDNESDAY, CWA WL BE UNDER THE INFLUENCE OF H5
LOW CLOSING OFF ACRS NERN U.S. MED RANGE GUIDANCE CONTS TO SUGGEST
THIS WL HAPPEN BY MID-WEEK AND EVENTUALLY HEAD EAST LATE IN THE
WEEK (PER 00Z/12Z EURO) OR HANG OUT THRU THE WEEKEND (PER 12Z GFS).
MAIN DIFFERENCES CNTR AROUND H5 HEIGHTS BEGINNING LATE IN THE
WEEK WITH EURO DROPPING WAVE INTO THE INTERMOUNTAIN WEST WHILE GFS
IS QUICKER WITH THIS WV AND MVS IT INTO THE DAKOTAS AT 12Z
THURSDAY. BY 00Z FRIDAY, ECMWF APPEARS TO TREAT IT AS A KICKER AND
KICKS THE UL TO THE EAST. GFS ALLOWS THIS WV TO GET ABSORBED AS IT
DROPS INTO THE TN VLY AND JUST RE-INTENSIFIES THE LOW OVR TOP OF
US. THE LATEST GFS IS QUITE A CHG FM ITS 06Z RUN AS IT APPEARED TO
BE IN LOCK-STEP WITH ECMWF. THUS, HV FOLLOWED 12Z EURO DUE TO ITS
CONSISTENCY WITH THE 00Z RUN.
EITHER WAY, SCTD POPS EXPECTED FM THURSDAY ON IN ONE FORM OR
ANOTHER, GENERALLY A RAIN/SNOW SHOWER MIX DRG THE DAYLIGHT HOURS
AND SNOW SHOWERS AT NIGHT. GIVEN THE EXTENSIVE CLD CVR EXPECTED
AND NW FLOW WORKING IN, TEMPS WL BE FAIRLY STEADY THRU THE PD WITH
ONLY A DEGREE OR TWO CHANGE BTWN THE OVRNGT LOWS AND AFTN HIGHS.
&&
.AVIATION /16Z MONDAY THROUGH FRIDAY/...
12Z UPDATE...
MOISTURE REMAINS TRAPPED UNDER INVERSION...WITH LIGHT NORTHWEST
FLOW OFF OF LAKE ONTARIO ALLOWING AT LEAST MVFR CIGS TO
PERSIST...AND EVEN STILL BRIEFLY IFR CIG KBGM AND KRME. GRADUAL
IMPROVEMENT AND EVENTUAL SCATTERING OUT WILL OCCUR DURING THE
AFTERNOON AS DRY AIR AND NEUTRALIZING INVERSION WIN OUT. CLEARING
AND QUIET TONIGHT. THOUGH NOT IN TAFS DUE TO UNCERTAINTY...SOME
MIST NOT OUT OF THE QUESTION FOR VALLEY TERMINALS DURING PREDAWN
HOURS TUESDAY MORNING.
.OUTLOOK...
TUE...VFR...THEN MVFR ENCROACHING FROM SW LATE TUE AFTN.
TUE NGT/WED MRNG...IFR/MVFR AND WINTRY MIX FROM LARGE SYSTEM.
WED AFTN THRU FRI...IFR/MVFR IN INTERMITTENT SNOW AND RAIN SHOWERS.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MDP
NEAR TERM...MLJ/MDP
SHORT TERM...HEDEN
LONG TERM...PVN
AVIATION...MDP
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
944 AM EST MON FEB 25 2013
.SYNOPSIS...
HIGH PRESSURE CENTERED OVER THE GREAT LAKES TODAY AS MOISTURE
SPREADS OVER OUR REGION FROM THE GULF OF MEXICO AHEAD OF A WARM
FRONT. STRONG LOW PRESSURE WILL MOVE FROM NORTHEAST TEXAS TODAY TO
WESTERN KENTUCKY LATE TUESDAY. A COLD FRONT WILL CROSS OUR AREA
WEDNESDAY EVENING.
&&
.NEAR TERM /THROUGH TONIGHT/...
930 AM UPDATE...HIGH TEMPS HAVE BEEN LOWERED A FEW DEGREES. CAD
WEDGE AND THICK CIRRUS DECK HAVE KEPT TEMPS COOLER THAN PREV FCST SO
FAR TODAY. LATEST AVBL MOS GUIDANCE AS WELL AS RAW MODEL TEMPS KEPT
PRACTICALLY ALL OF THE CWA IN THE 40S THROUGH THE DAY. FEEL THIS IS
APPROPRIATE. AS FOR PRECIP...LATEST RAP INDICATES A WAVE OF PRECIP
EARLY THIS AFTN THEN A LULL BEFORE WARM FRONTAL PRECIP TONIGHT.
DISCOUNTING THIS AS MODEL CONSENSUS IS FOR STEADILY INCREASING LLVL
ISENTROPIC FORCING FROM AFTN INTO EVENING...THUS OUR STEADILY
INCREASING POPS LOOK GOOD.
PREVIOUS DISCUSSION...
A WELL DEFINED ULVL CONFLUENT ZONE HAS SET UP ACROSS THE NE CONUS
WHICH IS ALLOWING A 1025 MB OH VALLEY SFC HIGH TO RIDGE EAST AND
SOUTH INTO THE REGION. MEANWHILE...AN H5 S/W IS CROSSING TO THE
SOUTH AND BRINGING IN A WIDE AREA OF CI. THIS SCENARIO IS CAPTURED
WELL BY THE OP MODELS ALONG WITH A DEEPENING H5 CUTOFF LOW PROGGED
TO MOVE INTO THE SRN MS RIVER VALLEY THROUGH THE PERIOD.
A FAIRLY STRONG WEDGE WILL DEVELOP TODAY WHILE MOISTURE FLUX OFF
BOTH THE GOM AND THE ATL ADVECT INTO THE AREA. CROSS SECTIONS ARE
PRETTY CONSISTENT ON THE GFS/NAM/SREF WITH THE DEEPER MOISTURE AND
ISENT OMEGA REACHING THE SRN ZONES AROUND 00Z AND SPREADING PRECIP
OVER THE ENTIRE CWFA QUICKLY THROUGH 03Z. POPS WERE ADJ DOWN EARLY
FOR A SOMEWHAT LATER ONSET TIME...BUT ALL AREAS SHOULD BE AT OR NEAR
100 POP BY 06Z THROUGH THE PERIOD.
THERE IS NOT A LOT OF COOLING NOR LOW TD/S ASSOCIATED WITH THIS
WEDGE...SO PRECIP TYPES OVERNIGHT WILL REMAIN RAIN AT ALL
LOCALES...EXCEPT FOR THE HIGHER TERRAIN OF THE BLACK MTNS AND THE
NRN MTNS WHERE PERIODS -FZRA WILL DEVELOP IN DIURNAL COOLING. MOST
OF THESE LOCATIONS WONT SEE SIGFNT ICE ACCUMS...BUT ISOLATED PEAKS
AROUND BEECH MTN COULD SEE A COUPLE TENTHS OF ICE AS THEY WILL
EXPERIENCE THE LONGEST PERIOD OF ICING BEFORE LLVL WAA CHANGES ALL
PRECIP TO RAIN. RAINFALL AMOUNTS OVERNIGHT WILL BE FAIRLY UNIFORM
ACROSS THE NC ZONES...AROUND AN INCH...AND UP TO AN INCH AND A HALF
ACROSS THE SRN ZONES AND NE GA. THIS WONT CREATE ANY FLOODING
CONCERN DUE TO THE 12 HR TIMEFRAME...BUT ADDITIONAL RAINFALL THROUGH
TUE MAY BEGIN TO ELEVATE SMALL STREAM AND CREEK LEVELS.
ANOTHER ISSUE WITH THIS SYSTEM WILL BE THE HIGHLY DYNAMIC OCCLUDED
SFC LOW TO THE WEST AND THE STRENGTHENING SFC RIDGE EAST. THIS WILL
SET UP A RATHER STRONG P/GRAD...BUT THE SFC WINDS WONT BECOME OVERLY
GUSTY WITH THE STRONGER VELOCITIES REMAINING ABOVE THE WEDGE
INVERSION. THE HIGHER ELEVATIONS OF THE WRN NC MTNS WILL LIKELY SEE
A SE/LY MTN WAVE SET UP AND DAMAGING WIND GUSTS FORCED TO THE SFC.
THE MODELS ARE SHOWING VERY GOOD ISENT DECENT AND RELATIVELY DEEP
NEG OMEGA AFT 06Z ALIGNED WITH WIND SPEEDS OF 55 KTS ABOVE 3.5 K
FEET. BASED ON GOOD CONFIDENCE WITH THIS IMPENDING SCENARIO...A HIGH
WIND WARNING WILL BE ISSUED FOR THE WRN NC MTNS ABOVE 3.5 K.
MAX TEMPS TODAY WILL BE ON THE COOL SIDE WITH WEDGE AND CLOUD COVER.
BLENDED THE OFFICIAL FCST WITH LOWER END METMOS GUIDANCE...WHICH
GAVE MAXES IN THE L50S NON/MTNS...AND U40S MTN VALLEYS. CONTINUED
NE/LY FLOW AND COOLER AIR ALOFT GUSTING TO THE SFC...YET HIGH CLOUD
COVER...LOWS SHOULD DROP TO RIGHT AROUND NORMAL.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 330 AM EST MONDAY...THE SHORT RANGE WILL BE DOMINATED BY THE
PASSAGE OF A LARGE AND DYNAMIC UPPER LOW MOVING FROM THE MID MS
VALLEY...UP THE OH VALLEY...TO THE LOWER GREAT LAKES THROUGH THE
PERIOD. THE MAIN ACTION WILL BE TUESDAY...WITH A CLASSIC COLD AIR
DAMMING WEDGE IN PLACE AT SUNRISE WITH PRECIP FALLING ACROSS NEARLY
THE ENTIRE FCST AREA. THERE ARE MANY CONCERNS. HIGH WIND POTENTIAL
WILL REMAIN HIGH ALONG THE TN BORDER SO THE HIGH WIND WARNING WILL
BE RUN THROUGH NOON. ANY LINGERING PRECIP TYPE ISSUES NEAR THE BLUE
RIDGE OVER THE NRN MTNS AND NRN FOOTHILLS SHOULD GO AWAY QUICKLY
AFTER SUNRISE WITH TEMPS WARMING ABOVE FREEZING. HEAVY RAIN IS ONE
OF THE PRIMARY CONCERNS...AND THE OTHER IS SEVERE WEATHER. MUCH OF
THIS WILL DEPEND ON THE TRACK OF A TRIPLE POINT LOW. THE LATEST
MODEL GUIDANCE SHOWS THIS FEATURE MOVING ACROSS THE MIDDLE OF SC AND
NC...OFF TO OUR EAST...DURING THE DAY. THIS WOULD TEND TO DECREASE
THE HEAVY RAIN THREAT OVER THE MTNS AND BLUE RIDGE ALONG THE SC/NC
BORDER. PW ANOMALIES ARE NOT OVERLY HIGH EITHER. WILL NOT ISSUE A
FLOOD WATCH AT THIS TIME OWING TO THE DOWNWARD QPF TREND. AS FOR THE
SEVERE WEATHER...IF THE TRIPLE POINT LOW TAKES A MORE WESTWARD TRACK
AS SHOWN BY THE NAM...WE COULD GET THE SRN/ERN PARTS OF METRO CLT
INTO THE WARMER AIR ON THE COASTAL SIDE OF THE WEDGE BOUNDARY IN THE
LATE AFTERNOON...WHICH WOULD INCREASE THE THREAT FOR SEVERE STORMS.
FOR NOW...WILL INCLUDE SOME THUNDER IN THE FCST THERE.
THE PRECIP SHOULD EXIT THE REGION DURING THE LATE AFTERNOON AND
EARLY EVENING ON TUESDAY...AFTER WHICH ANY LINGERING POP IS
RELEGATED TO THE MTNS...MOSTLY NEAR THE TN BORDER. THE MAIN CULPRIT
WILL BE WRAP-AROUND SHOWERS THROUGH TUESDAY NIGHT AND INTO
WEDNESDAY. THE LOW LEVEL FLOW REMAINS SW INITIALLY AND IS ONLY
SLOWLY EXPECTED TO COME AROUND TO W AND THEN NW WEDNESDAY NIGHT.
THUS...PRECIP POTENTIAL WILL GRADUALLY IMPROVE WEDNESDAY NIGHT AS
COLDER AIR MOVES IN TO CHANGE THE P-TYPE TO SNOW TOWARD DAYBREAK ON
THURSDAY. SOME ACCUM SHOULD BE EXPECTED ON THE TN BORDER...AND THIS
IS EXPECTED TO CONTINUE INTO THE MEDIUM RANGE.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 230 AM MONDAY...A DEEPENING LOW PRES SYSTEM WILL CONSOLIDATE
OVER WRN PA/NY EARLY THU. THERE IS GOOD MODEL CONSENSUS ON THE
LOCATION AND DEPTH OF THIS MAJOR FEATURE EARLY ON...BUT THEN VARYING
SOLUTIONS ON ADDITIONAL ENERGY PIVOTING AROUND THE LOW AND CROSSING
THE REGION FRI THROUGH SUN.
AS THE LOW SLOWLY DEPARTS PA AND NY AREA TO THE EAST THURS THROUGH
FRI...LOW LEVEL MOISTURE WILL BE IN PLACE OVER EAST TN UP AGAINST
THE NC MTNS. THIS MOISTURE WILL BE DEEPEST IN THIS MEDIUM RANGE
PERIOD ON THURS AND GRADUALLY DECREASE DEPENDING ON THE MODEL
REFERENCED INTO THE WEEKEND. 850MB TEMPS OVER THE MTNS WILL RANGE
FROM -5 TO -7C AT 12Z THURS BEING SLIGHTLY COLDEST IN THE ECMWF.
THESE 850MB TEMPS WARM A DEGREE OR TWO INTO FRI AND THEN COLDER
THROUGH THE WEEKEND DOWN TO -8 TO -11C 12Z SUNDAY. ALONG WITH THE
DEEPEST MOISTURE ON THURSDAY...THE WIND IS FORECAST TO BE FROM THE
WNW. AS THE LOW MOVES EAST ALONG WITH MORE SHALLOW MOISTURE...THE
WIND BECOMES NW WHICH IS MOST FAVORABLE FOR UPSLOPE SNOW SHOWERS.
SOME SHORTWAVE ENERGY ROUNDS THE BASE OF THE TROUGH LATE FRIDAY
ENHANCING THE UPSLOPE SNSH. ANOTHER SPOKE OF ENERGY CROSSES SAT PM
AND THE ECMWF CONTINUES TO HAVE A CUT OFF LOW WHICH KICKS OFF LIGHT
PRECIP OVER ALL OF THE WESTERN CAROLINAS AND NORTH GA SAT PM. THE
GFS HAS SOME PRECIP OVER NRN GA AND UPSTATE AND THE CMC LAYS OUT A
BROADER TROUGH AND SMALLER AMOUNTS OF SPOTTY PRECIP. THE UPPER
TROUGH AXIS IF FORECAST TO CROSS OUR AREA LATE SUNDAY. EXPECT MINS 5
TO 10 DEGREES BELOW NORMAL...WITH MAXES 10 TO 15 DEGREES BELOW
NORMAL...THROUGH THE PERIOD.
&&
.AVIATION /15Z MONDAY THROUGH FRIDAY/...
AT KCLT /15Z UPDATE/...LATEST PROG SOUNDINGS SHOW SOME MIXING
OCCURRING IN COLD WEDGE DESPITE MUCH SFC WARMING. SOME LOW END GUSTS
HAVE ALREADY OCCURRED AND MORE COULD OCCUR...BUT WINDS SHOULD
GRADUALLY INCREASE TO A STEADY 10KT OR SO REDUCING GUST FREQUENCY.
UPPER LEVEL CLOUDS WILL LOWER THROUGH THE PERIOD ALONG WITH PERHAPS
A FEW LOW VFR CLOUDS SEEN THIS AFTN. MVFR CIGS EXPECTED AFTER 03Z. A
CONTINUED LOWERING DECK TO IFR BY 10Z WILL BE ACCOMPANIED BY -SHRA.
THE WEDGE WILL STRENGTHEN AS THE PRECIP MOVES IN AND NE/LY WINDS
WILL VEER TO ENE/LY AROUND 00Z AND BECOME MODERATELY GUSTY THROUGH
THE REMAINDER OF THE TAF PERIOD.
ELSEWHERE...WITH A SFC WEDGE STRENGTHENING DURING THE DAY...WINDS
WILL BE MAINTAINED GENERALLY NE/LY AT ALL NON/MTN TAF SITES
BECOMING GUSTY AROUND 00Z. WINDS WILL HAVE LESS GUST
POTENTIAL...BUT STILL SUSTAINED AROUND 10 KTS...AT KAVL AND ALIGNED
SE/LY DOWN THE FRENCH BROAD VALLEY. ALL SITES WILL EXPERIENCE
LOWERING CIGS INTO MVFR ACCOMPANIED BY -SHRA BY 00Z WITH IFR
PROBABLE ACROSS THE UPSTATE AROUND 09Z.
OUTLOOK...CLEARING SKIES ARE IN STORE TUESDAY NIGHT WITH VFR
EXPECTED THROUGH THURSDAY EAST OF THE MOUNTAINS. SOME POTENTIAL FOR
MVFR ACROSS THE NC MTNS WITH SNOW SHOWERS MID TO LATE WEEK.
CONFIDENCE TABLE...
14-20Z 20-02Z 02-08Z 08-14Z
KCLT HIGH 100% HIGH 100% HIGH 94% HIGH 94%
KGSP HIGH 100% HIGH 100% HIGH 86% HIGH 92%
KAVL HIGH 100% HIGH 100% HIGH 84% HIGH 92%
KHKY HIGH 100% HIGH 100% HIGH 95% HIGH 92%
KGMU HIGH 100% HIGH 100% HIGH 87% HIGH 92%
KAND HIGH 100% HIGH 83% HIGH 91% HIGH 85%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...HIGH WIND WARNING FROM MIDNIGHT TONIGHT TO 6 PM EST TUESDAY
FOR NCZ033-048>052-058-059.
WIND ADVISORY FROM MIDNIGHT TONIGHT TO 6 PM EST TUESDAY FOR
NCZ033-048>052-058-059.
SC...NONE.
&&
$$
SYNOPSIS...DEO
NEAR TERM...SBK/WIMBERLEY
SHORT TERM...PM
LONG TERM...DEO
AVIATION...SBK/WIMBERLEY
AREA FORECAST DISCUSSION
NWS AMARILLO TX
833 AM CST MON FEB 25 2013
...CRIPPLING BLIZZARD ROARS ON...
.UPDATE...
GOING FORECAST STILL ON TRACK. THE NWS OFFICE NOW HAS OVER 13 INCHES
ON THE GROUND WITH 3-4 FOOT DRIFTS AND A MAX GUST TO 58 MPH. THE SE
TX PANHANDLE HAS BEEN SLOW TO FILL IN WITH SNOW AFTER THE
THUNDERSTORMS THAT DROPPED HEAVY RAIN LAST NIGHT AND THESE AREAS
MIGHT END UP WITH AMOUNTS CLOSER TO THE 8 INCH SIDE THAN THE 14 INCH
SIDE OF THEIR RANGE. AT THE END OF THE DAY...THE HEAVIEST TOTALS
WILL ALMOST CERTAINLY BE ALONG A PALO DURO CANYON TO AMARILLO TO
STINNETT TO PERRYTON LINE.
SOME RECORDS SEEM TO BE IN A PRECARIOUS POSITION TODAY. THE FIRST IS
AN ALL-TIME 24 HOUR SNOWFALL RECORD AT AMARILLO OF 20.6 INCHES FROM
MARCH 25-26 1934. WE WILL LIKELY GET VERY CLOSE OR SURPASS THIS
NUMBER BY THIS AFTERNOON.
THE OTHER IS THE ALL-TIME STATE OF TEXAS 24 HOUR SNOWFALL RECORD OF
25 INCHES IN FOLLETT SET MARCH 28 2009. SOMEWHERE IN THE
PERRYTON/STINNETT/BORGER/AMARILLO AREA COULD APPROACH THIS VALUE BY
THIS AFTERNOON.
SIMPSON
&&
.PREV DISCUSSION... /ISSUED 541 AM CST MON FEB 25 2013/
AVIATION.../12Z TAFS/
VERY HAZARDOUS FLYING CONDITIONS EXPECTED TO CONTINUE THROUGH AT
LEAST 00Z AT ALL TERMINALS. HEAVIEST SNOW AND LOWEST VISIBILITIES
WILL BE AT KAMA 15-20Z. AWW REMAINS IN EFFECT FOR KAMA AND TRADEWINDS
AIRPORT UNTIL 00Z.
VFR CONDITIONS ARE EXPECTED TO RETURN TO ALL TERMINALS 00-02Z.
NW WINDS ARE EXPECTED TO SUBSIDE BELOW 12 KT AT ALL TERMINALS BY 04Z.
JACKSON
PREV DISCUSSION... /ISSUED 446 AM CST MON FEB 25 2013/
.SNOW PILING UP...WINDS INCREASING AND CREATING FULL FLEDGED BLIZZARD
CONDITIONS AT THIS WRITING...
DISCUSSION...
MAIN CHANGE TO PREVIOUS FORECAST WAS TO ATTEMPT TO PIN POINT THE BAND
OF HIGHEST SNOW TOTALS...WHICH WILL LIKELY STRETCH ALONG AN ARC FROM
TULIA TO AMARILLO TO STINNETT TO SPEARMAN. LOCATIONS ON THIS ARC AND
30 MILES TO THE EAST AND WEST OF IT ARE SET TO RECEIVE AT LEAST A
FOOT OF SNOW...WITH TOTALS UP TO 2 FEET NOT COMPLETELY OUT OF THE
QUESTION. THE REST OF THE PANHANDLES WILL SEE SLIGHTLY LESSER
AMOUNTS...BUT STILL BLIZZARD CONDITIONS. SEE THE BLIZZARD WARNING AND
GRAPHICS ON WFO AMA HOMEPAGE AND FACEBOOK FOR A BETTER REPRESENTATION
OF THIS EVENT THAN CAN BE TYPED IN BLOCK TEXT.
THE NAM AND RUC HAVE DONE A GOOD JOB IN SHOWING A STRONG BAND OF
FRONTOGENETICAL FORCING...THOUGH THE PLACEMENT HAS BEEN TOO FAR EAST.
THIS BAND HAS SET UP OVER THE AFOREMENTIONED ARC AND CONVECTIVE
ENHANCEMENT WITH RATES TO 2-3 INCHES PER HOUR HAVE BEEN NOTED. IN
FACT...WE HAVE OBSERVED AT LEAST A HALF DOZEN CLOUD TO GROUND
STRIKES AT THE NWS AMA OFFICE OVERNIGHT...WITH ABOUT 6 INCHES
ALREADY ON THE GROUND AS OF 4 AM. INTENSE MESOSCALE BANDING SHOULD
PERSIST INTO THE MORING HOURS AND POSSIBLY INTO THE AFTERNOON...
THOUGH RATES WILL LIKELY SUBSIDE A BIT AFTER 18Z.
WINDS...
DOWNWARD MOMENTUM TRANSFER/MIXING OF A DEVELOPING 60-70KT LLJ WILL
RESULT IN FREQUENT GUSTS ABOVE 50 MPH AND POTENTIALLY A FEW GUSTS TO
65 MPH. THE WORST OF THE WINDS WILL OCCUR FROM 12-22Z TODAY.
ALL-IN-ALL...THE WELL ADVERTISED BLIZZARD IS COMING TO FRUITION
FOR THE VAST MAJORITY OF THE PANHANDLES. THE ONLY LOCATIONS THAT
WILL SEE REDUCED SNOWFALL AMOUNTS WILL BE THE FAR NW PANHANDLES...BUT
VERY STRONG WINDS WILL BLOW AROUND ANY MINOR SNOWFALL ACCUMULATIONS
AND STILL CREATE BRIEF BLIZZARD CONDITIONS.
TUESDAY THROUGH SUNDAY...
A COLD AND MAINLY DRY PERIOD WILL BE NOTED UNDER PREDOMINATELY NORTH
WINDS. A FEW WEAK UPR WAVES COULD KICK OFF A FLURRY TUE NIGHT AND
AGAIN THU...BUT NOTHING APPRECIABLE IS EXPECTED. WINDS MIGHT FINALLY
SWING AROUND TO THE SOUTH SAT NIGHT AND SUN...BUT QUICKLY COME BACK
TO THE NORTH BEHIND ANOTHER COLD FRONT ON SUNDAY NIGHT.
SIMPSON
FIRE WEATHER...
ELEVATED OR CRITICAL FIRE WEATHER CONDITIONS ARE NOT EXPECTED
THROUGH NEXT GIVEN THE EXPECTED SNOW COVER.
SIMPSON
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...BLIZZARD WARNING UNTIL 3 AM CST TUESDAY FOR THE FOLLOWING ZONES:
ARMSTRONG...CARSON...COLLINGSWORTH...DALLAM...DEAF SMITH...
DONLEY...GRAY...HANSFORD...HARTLEY...HEMPHILL...
HUTCHINSON...LIPSCOMB...MOORE...OCHILTREE...OLDHAM...
POTTER...RANDALL...ROBERTS...SHERMAN...WHEELER.
OK...BLIZZARD WARNING UNTIL 3 AM CST TUESDAY FOR THE FOLLOWING ZONES:
BEAVER...CIMARRON...TEXAS.
&&
$$
13/09
AREA FORECAST DISCUSSION...UPDATED
NWS AMARILLO TX
541 AM CST MON FEB 25 2013
.AVIATION.../12Z TAFS/
VERY HAZARDOUS FLYING CONDITIONS EXPECTED TO CONTINUE THROUGH AT
LEAST 00Z AT ALL TERMINALS. HEAVIEST SNOW AND LOWEST VISIBILITIES
WILL BE AT KAMA 15-20Z. AWW REMAINS IN EFFECT FOR KAMA AND TRADEWINDS
AIRPORT UNTIL 00Z.
VFR CONDITIONS ARE EXPECTED TO RETURN TO ALL TERMINALS 00-02Z.
NW WINDS ARE EXPECTED TO SUBSIDE BELOW 12 KT AT ALL TERMINALS BY 04Z.
JACKSON
&&
.PREV DISCUSSION... /ISSUED 446 AM CST MON FEB 25 2013/
..SNOW PILING UP...WINDS INCREASING AND CREATING FULL FLEDGED BLIZZARD
CONDITIONS AT THIS WRITING...
DISCUSSION...
MAIN CHANGE TO PREVIOUS FORECAST WAS TO ATTEMPT TO PIN POINT THE BAND
OF HIGHEST SNOW TOTALS...WHICH WILL LIKELY STRETCH ALONG AN ARC FROM
TULIA TO AMARILLO TO STINNETT TO SPEARMAN. LOCATIONS ON THIS ARC AND
30 MILES TO THE EAST AND WEST OF IT ARE SET TO RECEIVE AT LEAST A
FOOT OF SNOW...WITH TOTALS UP TO 2 FEET NOT COMPLETELY OUT OF THE
QUESTION. THE REST OF THE PANHANDLES WILL SEE SLIGHTLY LESSER
AMOUNTS...BUT STILL BLIZZARD CONDITIONS. SEE THE BLIZZARD WARNING AND
GRAPHICS ON WFO AMA HOMEPAGE AND FACEBOOK FOR A BETTER REPRESENTATION
OF THIS EVENT THAN CAN BE TYPED IN BLOCK TEXT.
THE NAM AND RUC HAVE DONE A GOOD JOB IN SHOWING A STRONG BAND OF
FRONTOGENETICAL FORCING...THOUGH THE PLACEMENT HAS BEEN TOO FAR EAST.
THIS BAND HAS SET UP OVER THE AFOREMENTIONED ARC AND CONVECTIVE
ENHANCEMENT WITH RATES TO 2-3 INCHES PER HOUR HAVE BEEN NOTED. IN
FACT...WE HAVE OBSERVED AT LEAST A HALF DOZEN CLOUD TO GROUND
STRIKES AT THE NWS AMA OFFICE OVERNIGHT...WITH ABOUT 6 INCHES
ALREADY ON THE GROUND AS OF 4 AM. INTENSE MESOSCALE BANDING SHOULD
PERSIST INTO THE MORING HOURS AND POSSIBLY INTO THE AFTERNOON...
THOUGH RATES WILL LIKELY SUBSIDE A BIT AFTER 18Z.
WINDS...
DOWNWARD MOMENTUM TRANSFER/MIXING OF A DEVELOPING 60-70KT LLJ WILL
RESULT IN FREQUENT GUSTS ABOVE 50 MPH AND POTENTIALLY A FEW GUSTS TO
65 MPH. THE WORST OF THE WINDS WILL OCCUR FROM 12-22Z TODAY.
ALL-IN-ALL...THE WELL ADVERTISED BLIZZARD IS COMING TO FRUITION
FOR THE VAST MAJORITY OF THE PANHANDLES. THE ONLY LOCATIONS THAT
WILL SEE REDUCED SNOWFALL AMOUNTS WILL BE THE FAR NW PANHANDLES...BUT
VERY STRONG WINDS WILL BLOW AROUND ANY MINOR SNOWFALL ACCUMULATIONS
AND STILL CREATE BRIEF BLIZZARD CONDITIONS.
TUESDAY THROUGH SUNDAY...
A COLD AND MAINLY DRY PERIOD WILL BE NOTED UNDER PREDOMINATELY NORTH
WINDS. A FEW WEAK UPR WAVES COULD KICK OFF A FLURRY TUE NIGHT AND
AGAIN THU...BUT NOTHING APPRECIABLE IS EXPECTED. WINDS MIGHT FINALLY
SWING AROUND TO THE SOUTH SAT NIGHT AND SUN...BUT QUICKLY COME BACK
TO THE NORTH BEHIND ANOTHER COLD FRONT ON SUNDAY NIGHT.
SIMPSON
FIRE WEATHER...
ELEVATED OR CRITICAL FIRE WEATHER CONDITIONS ARE NOT EXPECTED
THROUGH NEXT GIVEN THE EXPECTED SNOW COVER.
SIMPSON
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...BLIZZARD WARNING UNTIL 3 AM CST TUESDAY FOR THE FOLLOWING ZONES:
ARMSTRONG...CARSON...COLLINGSWORTH...DALLAM...DEAF SMITH...
DONLEY...GRAY...HANSFORD...HARTLEY...HEMPHILL...
HUTCHINSON...LIPSCOMB...MOORE...OCHILTREE...OLDHAM...
POTTER...RANDALL...ROBERTS...SHERMAN...WHEELER.
OK...BLIZZARD WARNING UNTIL 3 AM CST TUESDAY FOR THE FOLLOWING ZONES:
BEAVER...CIMARRON...TEXAS.
&&
$$
JJ/BJS
AREA FORECAST DISCUSSION
NWS AMARILLO TX
446 AM CST MON FEB 25 2013
...SNOW PILING UP...WINDS INCREASING AND CREATING FULL FLEDGED BLIZZARD
CONDITIONS AT THIS WRITING...
.DISCUSSION...
MAIN CHANGE TO PREVIOUS FORECAST WAS TO ATTEMPT TO PIN POINT THE BAND
OF HIGHEST SNOW TOTALS...WHICH WILL LIKELY STRETCH ALONG AN ARC FROM
TULIA TO AMARILLO TO STINNETT TO SPEARMAN. LOCATIONS ON THIS ARC AND
30 MILES TO THE EAST AND WEST OF IT ARE SET TO RECEIVE AT LEAST A
FOOT OF SNOW...WITH TOTALS UP TO 2 FEET NOT COMPLETELY OUT OF THE
QUESTION. THE REST OF THE PANHANDLES WILL SEE SLIGHTLY LESSER
AMOUNTS...BUT STILL BLIZZARD CONDITIONS. SEE THE BLIZZARD WARNING AND
GRAPHICS ON WFO AMA HOMEPAGE AND FACEBOOK FOR A BETTER REPRESENTATION
OF THIS EVENT THAN CAN BE TYPED IN BLOCK TEXT.
THE NAM AND RUC HAVE DONE A GOOD JOB IN SHOWING A STRONG BAND OF
FRONTOGENETICAL FORCING...THOUGH THE PLACEMENT HAS BEEN TOO FAR EAST.
THIS BAND HAS SET UP OVER THE AFOREMENTIONED ARC AND CONVECTIVE
ENHANCEMENT WITH RATES TO 2-3 INCHES PER HOUR HAVE BEEN NOTED. IN
FACT...WE HAVE OBSERVED AT LEAST A HALF DOZEN CLOUD TO GROUND
STRIKES AT THE NWS AMA OFFICE OVERNIGHT...WITH ABOUT 6 INCHES
ALREADY ON THE GROUND AS OF 4 AM. INTENSE MESOSCALE BANDING SHOULD
PERSIST INTO THE MORING HOURS AND POSSIBLY INTO THE AFTERNOON...
THOUGH RATES WILL LIKELY SUBSIDE A BIT AFTER 18Z.
WINDS...
DOWNWARD MOMENTUM TRANSFER/MIXING OF A DEVELOPING 60-70KT LLJ WILL
RESULT IN FREQUENT GUSTS ABOVE 50 MPH AND POTENTIALLY A FEW GUSTS TO
65 MPH. THE WORST OF THE WINDS WILL OCCUR FROM 12-22Z TODAY.
ALL-IN-ALL...THE WELL ADVERTISED BLIZZARD IS COMING TO FRUITION
FOR THE VAST MAJORITY OF THE PANHANDLES. THE ONLY LOCATIONS THAT
WILL SEE REDUCED SNOWFALL AMOUNTS WILL BE THE FAR NW PANHANDLES...BUT
VERY STRONG WINDS WILL BLOW AROUND ANY MINOR SNOWFALL ACCUMULATIONS
AND STILL CREATE BRIEF BLIZZARD CONDITIONS.
TUESDAY THROUGH SUNDAY...
A COLD AND MAINLY DRY PERIOD WILL BE NOTED UNDER PREDOMINATELY NORTH
WINDS. A FEW WEAK UPR WAVES COULD KICK OFF A FLURRY TUE NIGHT AND
AGAIN THU...BUT NOTHING APPRECIABLE IS EXPECTED. WINDS MIGHT FINALLY
SWING AROUND TO THE SOUTH SAT NIGHT AND SUN...BUT QUICKLY COME BACK
TO THE NORTH BEHIND ANOTHER COLD FRONT ON SUNDAY NIGHT.
SIMPSON
&&
.FIRE WEATHER...
ELEVATED OR CRITICAL FIRE WEATHER CONDITIONS ARE NOT EXPECTED
THROUGH NEXT GIVEN THE EXPECTED SNOW COVER.
SIMPSON
&&
.PRELIMINARY POINT TEMPS/POPS...
AMARILLO TX 30 12 35 18 38 / 100 20 5 20 5
BEAVER OK 30 4 35 18 34 / 100 60 5 10 5
BOISE CITY OK 34 12 40 16 35 / 70 5 5 20 5
BORGER TX 32 9 35 21 38 / 100 30 5 20 5
BOYS RANCH TX 34 8 40 21 40 / 100 10 5 20 5
CANYON TX 32 11 35 18 39 / 100 10 5 20 5
CLARENDON TX 31 17 35 22 39 / 100 30 5 10 5
DALHART TX 35 7 40 15 39 / 90 5 5 20 5
GUYMON OK 32 7 37 17 38 / 100 20 5 20 5
HEREFORD TX 33 9 38 18 39 / 100 5 5 20 5
LIPSCOMB TX 32 11 33 20 34 / 100 60 5 10 5
PAMPA TX 27 9 34 19 35 / 100 40 5 20 5
SHAMROCK TX 31 19 35 21 37 / 100 50 5 10 5
WELLINGTON TX 32 21 36 24 40 / 100 40 5 10 5
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...BLIZZARD WARNING UNTIL 3 AM CST TUESDAY FOR THE FOLLOWING ZONES:
ARMSTRONG...CARSON...COLLINGSWORTH...DALLAM...DEAF SMITH...
DONLEY...GRAY...HANSFORD...HARTLEY...HEMPHILL...
HUTCHINSON...LIPSCOMB...MOORE...OCHILTREE...OLDHAM...
POTTER...RANDALL...ROBERTS...SHERMAN...WHEELER.
OK...BLIZZARD WARNING UNTIL 3 AM CST TUESDAY FOR THE FOLLOWING ZONES:
BEAVER...CIMARRON...TEXAS.
&&
$$
13/09
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
530 AM CST MON FEB 25 2013
.SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT
230 AM CST MON FEB 25 2013
THE MAIN FOCUS THROUGH THE NEXT FEW DAYS IS ON THE SNOW
POTENTIAL...PARTICULARLY ON TUESDAY AS A LOW PRESSURE SYSTEM
TRACKS TO THE SOUTH OF THE REGION.
CURRENTLY TRACKING SOME SPOTTY LIGHT SNOW THAT HAS DEVELOPED ALONG
AN INVERTED SURFACE TROUGH AND AHEAD OF A MID LEVEL SHORTWAVE
TROUGH PUSHING INTO WESTERN MINNESOTA. THIS SNOW IS RUNNING INTO
AN AREA OF DRIER AIR AT THE SURFACE DUE TO A RIDGE AXIS THAT RUNS
ACROSS THE SOUTHERN GREAT LAKES TOWARD CENTRAL MINNESOTA. 25.07Z
RAP SOUNDINGS FROM ACROSS SOUTHEAST MINNESOTA INTO WESTERN
WISCONSIN SHOW A DEEPENING SATURATED LAYER THAT COINCIDES WITH THE
WEAK TO MODERATE LIFT FROM LOW LEVEL FRONTOGENESIS THIS MORNING
AND SHOULD HELP TO PROMOTE THE DEVELOPMENT OF THE LIGHT SNOW.
VISIBILITY HAS MAINLY BEEN IN THE 3-6SM RANGE ACROSS SOUTHEAST
MINNESOTA SO FAR THIS MORNING...BUT THERE HAVE BEEN TIMES WHEN IT
HAS DROPPED TO LESS THAN 2SM. REPORTS SO FAR FROM THIS AREA HAVE
BEEN THAT THERE HAS JUST BEEN A TRACE TO PERHAPS A TENTH OR TWO OF
SNOW ACCUMULATION. 25.00Z MESO-MODELS SUGGEST THAT THIS BAND WILL
LIFT TO THE NORTHEAST THIS MORNING TOWARD GREEN BAY AND GENERALLY
DISSIPATE IN COVERAGE AS THE LIFT WEAKENS. STILL KEPT SOME SMALL
CHANCES IN THROUGH 18Z WITH JUST THE TENTH OR TWO OF ACCUMULATION
EXPECTED. THE MAIN CONCERN IS JUST THE TIMING OF IT COMING IN
RIGHT BEFORE THIS MORNINGS COMMUTE WHICH COULD MAKE FOR A FEW
SLICK SPOTS IF IT CAN ACCUMULATE. THE 25.07Z RAP SOUNDINGS ALSO
INDICATE A POSSIBLE LOSS OF ICE LATER THIS MORNING...BUT THINK
THAT THE FORCING WILL HAVE CEASED AT THAT POINT AND IS LIKELY THE
REASON THE MID LEVEL SATURATION ENDS.
AS THE INVERTED SURFACE TROUGH WASHES OUT TODAY AND THE NEXT
SYSTEM TRACKS THROUGH THE OZARKS...THE SURFACE RIDGE AXIS WILL
LIFT NORTH OF THE REGION AND SHOULD KEEP ANY OF THE POTENTIAL FOG
THERE AS WELL. THE DRY LOW LEVEL AIR IN PLACE FROM THE RIDGE IS
ONE OF THE CONCERNS GOING INTO THE NEXT SYSTEM ON TUESDAY AND HOW
FAST THE COLUMN WILL BE ABLE TO SATURATE OUT.
CONFIDENCE REMAINS SOMEWHAT LOW IN HOW THE SYSTEM ON TUESDAY WILL PAN
OUT...BUT THE TREND STILL APPEARS TO BE FOR A SOUTHERN TRACK THAT
MAY KEEP MUCH OF THE FORECAST AREA ON THE DRY SIDE. THE 25.00Z NAM
IS A CONSIDERABLE OUTLIER WITH ITS TRACK TO THE NORTH AND HAS BEEN
CORRECTED WITH THE 25.06Z RUN. 25.00Z GFS/25.06Z NAM BUFKIT
SOUNDINGS SHOW A DRY LAYER BETWEEN 900MB AND 700MB THAT WILL TAKE
SOME TIME TO SATURATE OUT AS THE SYSTEM APPROACHES FROM THE
SOUTHWEST. HAVE REALLY SLOWED DOWN THE TIMING OF THE SNOW MOVING
IN ON TUESDAY FROM THE SOUTH AS THE DRY AIR APPEARS TO WIN OUT FOR
MUCH OF THE DAY. THROUGH 00Z WEDNESDAY...THE BEST CHANCES FOR ANY
SNOW APPEAR TO BE IN CLAYTON/GRANT COUNTIES...THOUGH THE ONLY
25.00Z MODEL THAT HAS ANY SNOW IN THERE BY THAT TIME IS THE GFS
WHICH IS NOTORIOUSLY HIGH ON ITS HUMIDITY AT TIMES. THUS...MORE
ADJUSTMENTS MAY BE NEEDED IN FORECAST AS CONFIDENCE INCREASES THAT
THE SNOW WILL NOT OCCUR. THIS 12Z TUESDAY THROUGH 00Z WEDNESDAY
PERIOD IS CRUCIAL BECAUSE IT IS GOING TO BE THE MAIN TIME FRAME
FOR ANY DECENT SNOWFALL ACCUMULATION. AFTER 00Z WEDNESDAY...THE
SYSTEM LOSES A LOT OF ITS DEEP/STRONG FORCING AS THE LOW FILLS
INTO THE NIGHT. FOR NOW...HAVE MAINTAINED SOME 2-4 INCH SNOW
AMOUNTS FOR CLAYTON/GRANT COUNTY WITH LESS THAN 2 INCHES NORTHWEST
OF THERE TUESDAY INTO TUESDAY NIGHT...BUT AS
MENTIONED...CONFIDENCE IN THIS OCCURRING IS FAIRLY LOW AND BASED
ON THIS WOULD NOT THINK THAT AN ADVISORY IS GOING TO BE NEEDED.
HOW LONG THE LIGHT SNOW MAY LINGER IS ALSO IN QUESTION AS 25.00Z
GFS/25.06Z NAM BUFKIT SOUNDINGS SHOW WEAK LIFT AND DIMINISHING
SATURATION OF THE COLUMN INTO WEDNESDAY NIGHT. MAINTAINED SOME
CHANCES OF SOME LIGHT SNOW WITH THE HIGHEST CHANCES ACROSS
SOUTHWEST WISCONSIN AND NORTHEAST IOWA WHERE THE CORE OF THE UPPER
LEVEL LOW WILL TRACK ACROSS. ANY SNOW AMOUNTS OVER THIS PERIOD
WOULD BE LIGHT AT LESS THAN AN INCH.
.LONG TERM...THURSDAY THROUGH SUNDAY
320 AM CST MON FEB 25 2013
AFTER THE SYSTEM MOVES OFF TO THE EAST COAST BY MID WEEK...A BROAD
RIDGE OF HIGH PRESSURE WILL EXTEND DOWN FROM NORTH CENTRAL CANADA
DOWN TO THE GULF COAST AND REMAIN ACROSS THE UPPER MISSISSIPPI
RIVER VALLEY REGION INTO NEXT WEEKEND. WHILE THE LOW TO UPPER
LEVEL FLOW WILL BE OUT OF THE NORTH...THERE IS NOT MUCH OF A COLD
SOURCE TO PULL FROM OUT OF CENTRAL CANADA...SO TEMPERATURES SHOULD
NOT TAKE MUCH OF A HIT THROUGH THE WEEK. CLEARING SKIES AND AN
INCREASING SUN ANGLE WILL HELP AS WELL TO KEEP TEMPERATURES NEAR
NORMAL.
&&
.AVIATION...TODAY AND TONIGHT
530 AM CST MON FEB 25 2013
CLOUDS WILL BE THE RULE ACROSS THE TAF SITES TODAY/TONIGHT...BUT
MOSTLY BE AOA 3500 FT AS THE LOWER LEVEL AIRMASS ACROSS THE AREA
REMAINS ON THE DRY SIDE. DUE TO A MORE MOIST BOUNDARY LAYER AND WEAK
GRADIENT/LIGHT WINDS...SOME MVFR VSBYS IN BR WILL PREVAIL ACROSS THE
HIGHER TERRAIN AREAS OF NORTHEAST IA/SOUTHEAST MN THRU MUCH OF THIS
MORNING. WEAK FORCING/LIFT WILL CONTINUE TO SPREAD ACROSS THE AREA
EARLY THIS MORNING. THIS LIFT WAS PRODUCING SOME -SN AROUND KLSE
INTO WESTERN WI. AS THE LIFT WEAKENS/EXITS BY MID MORNING THIS -SN
WILL EXIT EAST OF THE KLSE AREA...WITH VFR VSBYS THEN EXPECTED TO
PREVAIL AT BOTH KRST/KLSE FOR THE LATE MORNING HOURS AND THRU
TONIGHT.
CLOUD COVER TONIGHT...AHEAD OF THE SYSTEM LIFTING OUT OF THE
SOUTHERN PLAINS...ALONG WITH INCREASING NORTHEAST WINDS AS THE SFC
LOW LIFTS INTO SOUTHERN MO...ARE EXPECTED TO PREVENT ANY MVFR BR
DEVELOPMENT TONIGHT INTO TUE MORNING.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
320 AM CST MON FEB 25 2013
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM....HALBACH
AVIATION.....RRS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
414 PM EST MON FEB 25 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 413 PM EST MON FEB 25 2013
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A SPLIT FLOW PATTERN
ACROSS NAMERICA. IN THE SRN STREAM...A WELL-DEFINED MID LEVEL LOW
WAS OVER N TX. IN THE NRN STREAM...A SHORTWAVE TROF EXTENDS FROM
HUDSON BAY TO THE UPPER MISSISSIPPI VALLEY. SOME FLURRIES HAVE BEEN
NOTED IN WI TODAY IN AN AREA OF WEAK ISENTROPIC ASCENT. SOME OF
THOSE FLURRIES MAY HAVE SLIPPED INTO SCTNRL UPPER MI THIS AFTN
ALTHOUGH NO REPORTS HAVE BEEN NOTED. OTHERWISE...MOSTLY CLOUDY SKIES
HAVE BEEN THE RULE TODAY...THOUGH THERE WAS A PERIOD OF MOSTLY SUNNY
SKIES FOR A TIME EARLIER OVER THE FAR W AND NW.
ALTHOUGH THE SHORT TERM PORTION OF THE FCST WILL FEATURE TRANQUIL
WEATHER...CLOUDS AND TEMPS WILL OFFER SOME CHALLENGING ASPECTS TO
THE FCST. UNDER WEAK ISENTROPIC ASCENT...WILL MAINTAIN A MENTION OF
A FEW FLURRIES INTO THE EVENING HRS OVER THE SRN PORTION OF THE FCST
AREA. CLOUD FCST IS NOT CERTAIN AT ALL AND THAT OPENS THE DOOR TO
BIG TEMP BUST POTENTIAL TONIGHT. UNDER LIGHT SW FLOW INTO THE
EVENING...MULTI-LAYERED CLOUDS TO THE SW SHOULD AFFECT MUCH OF THE
FCST AREA. OVERNIGHT...LOW-LEVEL WIND FIELDS BECOME VERY LIGHT WITH
A TREND TO LIGHT EASTERLY LATE WHICH SUGGESTS LITTLE ADVECTION OF
DRIER AIR. THUS...IT WOULD SEEM THAT MUCH OF THE AREA WILL SEE
MOSTLY CLOUDY SKIES TONIGHT. HOWEVER...THE PROXIMITY OF CLEAR SKIES
JUST TO THE W SUGGESTS THE WRN FCST AREA MAY HAVE THE BEST SHOT OF
SEEING A PERIOD OF PARTLY CLOUDY AND POSSIBLY CLEAR SKIES TONIGHT.
ALL IN ALL...THERE IS VERY LOW CONFIDENCE ON SKY CONDITION THRU THE
NIGHT. WITH LIGHT/CALM WINDS AT THE SFC...TEMPS WILL FALL
SIGNIFICANTLY IN SOME AREAS IF SKIES BECOME CLEAR/PARTLY CLOUDY FOR
A TIME. THIS COULD ALSO LEAD TO SOME FOG DEVELOPMENT. AT THIS
POINT...WILL PLAY IT CONSERVATIVE UTILIZING A CONSENSUS APPROACH TO
TEMPS...BUT WILL GO WITH LOWEST MIN TEMPS OVER THE W (MID TEENS)
WHERE IT APPEARS THERE IS A BETTER SHOT OF SEEING LESS CLOUDS FOR AT
LEAST A PORTION OF THE NIGHT. COULD EASILY SEE TEMPS FALL INTO THE
SINGLE DIGITS IF ANY LOCATIONS END UP CLEAR FOR A FEW HRS.
E TO NE WINDS WILL DEVELOP TUE AS UPPER MI FALLS INTO THE NRN
PERIPHERY OF THE CIRCULATION AROUND SRN STREAM LOW. WINDS WILL BE
STRONGEST IN THE MENOMINEE AREA AS A STIFF NE WIND WILL BE THE RULE
IN THE AFTN DUE TO COASTAL CONVERGENCE/FUNNELING DOWN THE BAY.
STRATOCU SHOULD TEND TO BREAK UP AS MODELS SUGGEST SOME DRYING...
BUT THE LWR CLOUDS WILL PROBABLY HANG ON LONGEST WHERE EASTERLY
WINDS UPSLOPE. WHERE LOW CLOUDS SCATTER OUT OR CLEAR...THERE SHOULD
BE A FAIR AMOUNT OF SUNSHINE THRU ONLY SOME HIGH CLOUDS. EXPECT MAX
TEMPS IN THE 30S...COOLEST (LOW 30S) AT LOCATIONS WHERE WINDS ARE
OFF THE LAKES AND IN THE UPSLOPE AREAS. TEMPS COULD RISE TO NEAR 40
IN LOCATIONS THAT SEE DOWNSLOPING WITH EASTERLY WINDS.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 413 PM EST MON FEB 25 2013
THREE SHORTWAVES WILL INFLUENCE THE WEATHER FOR MUCH OF THE EASTERN
HALF OF THE CONUS OVER THE NEXT SEVERAL DAYS AND SETUP THE WEATHER
PATTERN HEADING INTO THE FIRST WEEK OF MARCH.
THE FIRST WAVE IS CURRENTLY SPINNING IN THE SOUTHERN PLAINS AND WILL
EJECT TOWARDS THE LOWER GREAT LAKES ON TUESDAY INTO TUESDAY
NIGHT...WHILE THE NEXT WAVE DIVES SOUTHEAST ACROSS THE CENTRAL
ROCKIES. MODELS HAVE BECOME MUCH MORE CONSISTENT WITH THIS SYSTEM IN
THE LAST 24 HOURS...AS THERE WERE DIFFERENCES IN THE INTERACTION
BETWEEN THE FIRST AND SECOND WAVES...WITH THE MERGER AND NORTHWARD
EXTENT. EVERYTHING SEEMS TO HAVE COME INTO AGREEMENT WITH THE
CONSISTENT ECMWF ON A MORE SOUTHERN TRACK THAT JUST BRUSHES THE FAR
SOUTHEAST PART OF UPPER MICHIGAN /NEAR LAKE MICHIGAN/ WITH LIGHT
SNOW LATE TUESDAY NIGHT INTO WEDNESDAY EVENING. ANY SLIGHT
DIFFERENCES IN THE NORTHWEST EXTENT OF THE TRACK WILL NOT ONLY
AFFECT THE SNOW NEAR LAKE MICHIGAN...BUT ALSO THE POTENTIAL FOR
LIGHT LAKE ENHANCEMENT OR UPSLOPE PRECIPITATION WITH THE
NORTH-NORTHEAST FLOW AROUND THE LOW. WITH THE LIMITED COLD AIR IN
PLACE AT THIS TIME...IT LOOKS LIKE 850MB TEMPS ON WEDNESDAY ARE ONLY
AROUND -5C...SO DELTA-T VALUES ARE FAIRLY MARGINAL. WHEN COMBINING
THAT WITH LIMITED MOISTURE...UNLESS THE FARTHER NW 06Z NAM IS
CORRECT...WOULDN/T THINK AREAS AWAY FROM LAKE MICHIGAN WOULD SEE
MUCH MORE THAN LOW CLOUDS AND UPSLOPE FLURRIES OR LIGHT SNOW OVER
THE NORTH CENTRAL ON WEDNESDAY PENDING ENOUGH MOISTURE. MODELS ARE
IN BETTER AGREEMENT ON LOW LEVEL MOISTURE MOVING IN ON WEDNESDAY
NIGHT AS THE LOW SHIFTS EAST INTO NEW YORK. THIS IS IN RESPONSE TO
ADDITIONAL MOISTURE ASSOCIATED WITH A NORTHERN STREAM SHORTWAVE
MOVING THROUGH SOUTHERN CANADA. THIS WILL LIKELY LEAD TO THE BEST
POTENTIAL FOR PRECIPITATION FOR AREAS NEAR LAKE SUPERIOR WEDNESDAY
NIGHT INTO THURSDAY. 850MB TEMPS ARE STILL MARGINAL THROUGH THIS
PERIOD...BUT DO DROP TO -10C. WITH THE MARGINAL DELTA-T VALUES AND
AN INVERSION HEIGHT SITTING AROUND 4KFT...THINKING THAT THE LIGHT
SNOW SHOWERS WILL REMAIN IN THE NORTH-NORTHEAST FAVORED LOCATIONS OF
NORTHERN UPPER MICHIGAN. STRONGEST SHOWERS SHOULD OCCUR OVER THE
HIGHER TERRAIN OF NORTH CENTRAL UPPER MICHIGAN...WHERE UPSLOPE FLOW
WILL AID THE FORCING SOME. WILL CONTINUE TO MENTION SLIGHTS AND LOW
CHANCE POPS IN THESE AREAS INTO THURSDAY NIGHT.
MEANWHILE...THE THIRD MAIN SHORTWAVE WILL BE DIVING SOUTHEAST
THROUGH THE ROCKIES ON WEDNESDAY NIGHT AND THURSDAY AND AMPLIFY THE
UPPER TROUGH OVER THE EASTERN CONUS. THIS WILL LEAD THE UPPER GREAT
LAKES INTO A COLDER THAN NORMAL PERIOD FOR THE LAST DAY OF FEBRUARY
AND THE FIRST WEEK OF MARCH. WHILE THIS BRINGS GRADUALLY COLDER AIR
/925-900MB TEMPS FALLING TOWARDS -12 TO -14C/...IT WILL ALSO PUSH A
HIGH PRESSURE RIDGE OVER THE AREA FROM A HIGH CENTERED OVER HUDSON
BAY. THIS SUBSIDENCE WILL WORK TO LOWER THE INVERSION HEIGHTS BELOW
3KFT BY FRIDAY MORNING. THEREFORE...WOULD JUST EXPECT LINGERING
LOW CLOUDS AND AN ISOLATED SNOW SHOWER FOR FRIDAY INTO SATURDAY
OVER LOCATIONS NEAR LAKE SUPERIOR. THERE ARE SOME DIFFERENCES IN
THE WIND DIRECTION ROTATING AROUND THE HIGH...BUT WILL MAINLY FOCUS
THE SLIGHT CHANCES OVER THE NORTH CENTRAL.
DIFFERENCES ARRIVE HEADING INTO THE SECOND HALF OF THE WEEKEND WITH
THE HANDLING OF A SHORTWAVE DROPPING THROUGH ON THE BACK SIDE OF
THE RIDGE OVER THE WESTERN CONUS. THE 00Z ECMWF KEEPS THE RIDGE
FARTHER TO THE WEST BEHIND THE SHORTWAVE...WHILE THE 12Z GFS PUSHES
IT INTO THE UPPER GREAT LAKES. DEPENDING ON THE SOLUTION...THIS
WILL EITHER KEEP THE AREA UNDER THE SURFACE RIDGE INTO THE FIRST
PART OF NEXT WEEK OR HAVE THE AREA INFLUENCED BY THE NEXT CLIPPER
SYSTEM APPROACHING FOR MONDAY. WILL GO WITH THE PERSISTENT HIGH AND
DRIER SOLUTION INTO MONDAY.
AFTER A FAIRLY ACTIVE PERIOD FOR THE LAST COUPLE OF WEEKS OF
FEBRUARY...IT/S LOOKING LIKE MARCH WILL COME IN LIKE A LAMB FOR
MUCH OF THE UPPER GREAT LAKES REGION. FORTUNATELY...THIS ACTIVE
PERIOD BROUGHT THE AREA CLOSER TO NORMAL SNOWFALL...ALTHOUGH SOME
LOCATIONS ARE STILL BELOW NORMAL ON SNOWFALL /OUR OFFICE/ AND SNOW
WATER EQUIVALENT /MICHIGAMME RIVER BASIN/. BUT LOOKING AT MODEL RUN
QPF...THE NEXT 10 DAYS DON/T APPEAR TO BE TOO PROMISING FOR
ADDITIONS TO THE SNOW PACK. 00Z ECMWF ONLY SHOWS 10 DAY ACCUMULATION
OF 0.02-0.08 INCH FOR THE ENTIRE CWA. 00Z GFS FOR THE
SIMILAR PERIOD KEEPS VALUES UNDER 0.25 OF AN INCH...WITH MUCH OF
THAT COMING FROM THE SYSTEM BRUSHING THE AREA ON WEDNESDAY AND
THURSDAY. ON THE POSITIVE SIDE...THE EXISTING SNOWPACK WILL REMAIN
IN PLACE AS TEMPERATURES TREND TOWARDS A COOLER THAN NORMAL PERIOD
FOR THE AREA FRIDAY INTO THE NEXT WORK WEEK /HIGHS IN THE 20S AND
LOWS IN THE SINGLE DIGITS ABOVE ZERO/.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1237 PM EST MON FEB 25 2013
VFR CONDITIONS SHOULD PREVAIL THRU THE FCST PERIOD AT KIWD/KCMX...
THOUGH PROXIMITY OF LOWER CIGS JUST TO THE S AND SW MAY RESULT IN
MVFR CIGS DEVELOPING AT KIWD AND PERHAPS AT KCMX THIS AFTN/EVENING.
SHOULD SKIES CLEAR TONIGHT...FOG AND POSSIBLE IFR CONDITIONS COULD
DEVELOP AT KIWD/KCMX. AT KSAW...HIGH MVFR CIGS ARE LIKELY TO PREVAIL
INTO THE EVENING GIVEN UPSTREAM MVFR CIGS. IF CLOUDS SCATTER OUT
LATER TONIGHT...IFR CONDITIONS COULD ALSO DEVELOP AT KSAW.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 413 PM EST MON FEB 25 2013
ALTHOUGH HIGH PRES WILL BE DEPARTING...WINDS WILL REMAIN UNDER 20KT
PROBABLY THRU TUE AFTN. THEREAFTER...TIGHTENING PRES GRADIENT BTWN
HIGH PRES TO THE N AND NW AND LOW PRES TRACKING THRU THE LOWER OHIO
VALLEY TO LOWER LAKES TUE/WED WILL RESULT IN NORTHEASTERLY WINDS
INCREASING TO 20-30KT TUE NIGHT THRU WED. MIGHT SEE A FEW GALE FORCE
GUSTS WED OVER THE E HALF. EVEN THOUGH THE LOW CONTINUES TO MOVE E
THU...THE HIGH BUILDING TOWARD THE AREA FROM N WILL MAINTAIN A TIGHT
PRES GRADIENT...RESULTING IN CONTINUED 20-30KT WINDS WITH SOME
GALE FORCE GUSTS POSSIBLE OVER THE E HALF. WINDS WILL THEN VERY
SLOWLY DIMINISH FROM W TO E FRI/SAT AS THE HIGH PRES MOVES CLOSER...
BUT IT WILL PROBABLY BE SAT BEFORE WINDS DROP BLO 20KT ACROSS THE
ENTIRE LAKE. ALONG WITH THE PERIOD OF STRONGER WINDS MID
WEEK...FREEZING SPRAY IS ALSO EXPECTED.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...SRF
AVIATION...ROLFSON
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1239 PM EST MON FEB 25 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 337 AM EST MON FEB 25 2013
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW SPLIT FLOW
DOMINATING THE FLOW OVER NAMERICA. RDG IN THE NRN BRANCH IS PRESENT
FM JAMES BAY INTO THE UPR GRT LKS TO THE W OF DEPARTING CLOSED LO IN
SE CANADA/NEW ENGLAND...AND A SFC HI PRES RDG EXTENDS FM NE ONTARIO
THRU ECENTRAL UPR MI INTO THE UPR MIDWEST. WITH DRY AIR AOA H8 AS
SHOWN ON 00Z APX/GRB RAOBS AND LARGER SCALE SUBSIDENCE UNDER THE
RDG...THERE IS NO PCPN IN THE AREA. EVEN LES IS ABSENT WITH LLVL
ACYC FLOW AND H85 TEMPS -6C AT INL AND GRB. DESPITE PASSAGE OF SFC
RDG AXIS...QUITE A BIT OF LO CLD LINGERS WITH SOME MSTR/RELATIVELY
HI SFC DEWPTS TRAPPED BLO SUBSIDENCE INVRN H825-875 SHOWN ON THE 00Z
APX/GRB RAOBS. SOME CLRG HAS OCCURRED OVER THE W AND NEAR THE WI
BORDER INTO NE MN/NRN WI...WHERE SOME LLVL DRY AIR SHOWN ON THE 00Z
GRB/MPX RAOBS HAS SHIFTED TO THE N. WHERE SKIES HAVE CLRD...TEMPS
FELL OFF SHARPLY IN THE PRESENCE OF NEAR CALM WINDS. SOME PATCHY
FOG/ST HAS ALSO DVLPD...SO THE CLRG HOLES ARE IN SOME CASES SHORT
LIVED. ALTHOUGH THERE ARE MORE HOLES IN THE LO CLDS OVER FAR NRN
WI/NE MN...MORE LO/MID CLDS ARE STREAMING NEWD INTO CNTRL MN/WI IN
THE LLVL SW FLOW BTWN RDG AXIS OVER UPR MI AND LO PRES TROF
EXTENDING FM LK WINNIPEG INTO THE NRN PLAINS ASSOCIATED WITH PAIR OF
NRN BRANCH DISTURBANCES. A POTENT DISTURBANCE IN THE THE SRN BRANCH
IS PRESENT OVER THE SRN ROCKIES.
MAIN FCST CONCERNS IN THE SHORT TERM ARE TRICKY CLD TRENDS/IMPACT ON
TEMPS.
DESPITE SOME DIURNAL HEATING FM INCRSG SUN ANGLE AND SW FLOW ON THE
BACK SIDE OF HI PRES THAT WL ELIMINATE ANY LK SUP INFLUENCE AND
ADVECT SOME DRIER AIR THAT HAS CAUSED CLRG OVER NW WI...RECENT
TRENDS INDICATE LO CLDS MIGHT PROVE QUITE RESILIENT OVER THE CWA
WITH MORE MORE LO CLDS TENDING TO FORM OVER NRN WI. THE WINDOW FOR
CLRG WL BE RELATIVELY SHORT AS WELL BECAUSE BOTH 00Z NAM/GFS
INDICATE CLDS NOW STREAMING NEWD TOWARD CENTRAL WI AHEAD OF PAIR OF
SLOWLY APRCHG NRN BRANCH DISTURBANCES WL ARRIVE AT THE WI BORDER
LATER THIS MRNG. INCLUDED A MENTION OF FLURRIES OVER THE SCENTRAL
THIS AFTN WITH SOMEWHAT DEEPER MSTR UNDER AREA OF WEAK DEEP LYR
QVECTOR CNVGC. WITH ABUNDANT CLD COVER MORE LIKELY...WL TEND TOWARD
THE LOWER END OF GUIDANCE FOR MAX TEMPS...WHICH IS IN GOOD AGREEMENT
WITH GOING FCST. EXPECT THE HIER MAX TEMPS OVER THE NCENTRAL FM
BARAGA-MQT WHERE LLVL SSW FLOW DOWNSLOPES.
TNGT...AS PAIR OF NRN BRANCH SHRTWVS SHIFT E INTO THE UPR LKS...
GUIDANCE SHOWS THESE DISTURBANCES FADING UNDER LARGER SCALE HGT
RISES ASSOCIATED WITH BLDG UPR RDG ON NRN FLANK OF STRONGER SRN
BRANCH DISTURBANCE MOVING INTO THE MID-MS RIVER VALLEY. ALTHOUGH
LLVL FLOW TENDS ACYC...WINDS ARE FCST TO BE LGT. SO RATHER MOIST
LLVLS WL BE LINGERING IN THE ABSENCE OF SGNFT LLVL DRYING. THE
QUESTION IS WHETHER LARGER SCALE SUBSIDENCE WL RESULT IN THE BREAK
UP OF THIS LO CLD. IN THE ABSENCE OF SGNFT LLVL DRYING AND IN THE
PRESENCE OF DIURNAL COOLING...SUSPECT THE RESULT WL BE LINGERING LO
CLDS THRU THE NGT WITH SUBSIDENCE STRENGTHENING THE INVRN THAT TRAPS
THIS MSTR. CONSIDERING THE UNCERTAINTY...MADE FEW CHGS TO GOING MIN
TEMPS FCST. IF THE LO CLDS ARE MORE PERSISTENT...FCST MIN TEMPS IN
THE UPR TEENS/LO 20S WL HAVE TO BE RAISED.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 337 AM EST MON FEB 25 2013
UPPER MICHIGAN LOOK TO BE TAKING A BREAK FROM THE MODERATE TO HEAVY
SNOW THAT HAS BEEN COMMON PLACE OVER THE PAST WEEK OR SO.
THE CURRENT 500MB LOW SWINGING ACROSS NORTHERN TEXAS THIS MORNING
SHOULD BE OVER NORTHERN ARKANSAS/SOUTHERN MISSOURI BY 12Z
TUESDAY...WITH THE RIDGE EXTENDING FROM THE ATLANTIC BACK THROUGH
UPPER MICHIGAN/LAKE SUPERIOR/NORTHERN MINNESOTA.
THE 500MB RIDGE WILL BE QUICKLY PUSHED NORTH OF THE AREA DURING THE
DAY TUESDAY...WITH THE THEN NEARLY STACKED SFC-500MB SHOULD BE ABLE
TO LIFT TO SOUTHERN ILLINOIS/INDIANA. E-ENE WINDS WILL BE ON THE
INCREASE ACROSS UPPER MICHIGAN...AND IN PARTICULAR ALONG LAKE
MICHIGAN. WITH SURFACE TEMPERATURES IN THE LOW 30S...AND 850MB TEMPS
HOVERING AROUND -3C NO LAKE EFFECT SNOW IS EXPECTED. IN FACT...DRY
WEATHER SHOULD BE THE RULE THROUGH TUESDAY EVENING.
THE 25/00Z NAM IS A STRONGER FAR NORTHERN OUTLIER WITH THE 500MB
LOW...BRINGING THE 500MB LOW OVER CENTRAL LOWER MI BY 18Z WEDNESDAY.
THE CONSENSUS OF THE GFS/ECMWF/CANADIAN HAS THE FEATURE SOUTH OF
DETROIT... NORTHERN OHIO...OR ACROSS NORTHWESTERN PENNSYLVANIA. THE
DIVERGENCE OF THE NAM SOLUTION IS MOST DRAMATIC AFTER 00Z
WEDNESDAY...AND WILL THEREFORE NOT BE UTILIZED IN OUR ONGOING
FORECAST BEYOND THAT POINT. TO A LESSER EXTENT THE CANADIAN BRIDGES
THE GAP BETWEEN THE FASTER GFS/ECMWF AND THE NORTHWESTERLY NAM...BUT
ENDS UP RUNNING APPROXIMATELY 12HRS BEHIND THE ECMWF BY THURSDAY /AT
500MB ACROSS NEW YORK AND THE NEW ENGLAND STATES. MAY NEED TO ADD
FLURRIES FOR UPSLOPE AREAS OF NORTH CENTRAL UPPER MICHIGAN NEAR LAKE
SUPERIOR LATE WEDNESDAY AFTERNOON ON.
EXPECT A SHORTWAVE TO SWING ACROSS ONTARIO WEDNESDAY NIGHT INTO
THURSDAY...BUT HAVE LITTLE INFLUENCE ON OUR WEATHER OTHER THAN
KEEPING CLOUDS OVERHEAD. 850MB TEMPS WILL BE ABLE TO DROP TO AROUND
-8C THURSDAY AS COOLER AIR PUSHES IN BEHIND THE MAIN LOW. WITH N-NNE
WINDS OFF LAKE SUPERIOR THERE WILL BE AN INCREASED CHANCE OF LIGHT
LAKE EFFECT SNOW SHOWERS...WITH A SLIGHT INCREASE IN LOW LEVEL
MOISTURE...DESPITE A STRONG INVERSION NOTED OFF THE GFS HOVERING
NEAR 850MB. THE DGZ LOOKS TO REBOUND...ALTHOUGH THIN /ABOUT 50MB
THICK/ LATE WEDNESDAY NIGHT THROUGH SATURDAY MORNING.
ANOTHER 500MB RIDGE WILL BE ABLE TO PUSH ACROSS THE UPPER GREAT
LAKES THURSDAY THROUGH MUCH OF FRIDAY. EXPECT COOLER AIR TO FILTER
IN AGAIN FRIDAY NIGHT...AND TAKE HOLD OF THE UPPER GREAT LAKES BY
SUNDAY AS 850MB TEMPS FALL FROM AROUND -10C TO -13 OR -14C. WIND
DIRECTION DOES NOT CHANGE MUCH DURING THIS TIME...WITH FAIRLY STEADY
N-NE WINDS SLIDING IN OFF LAKE SUPERIOR. AS A RESULT...IT WILL BE
DIFFICULT TO TAKE OUT THE MENTION OF LIGHT SNOW SHOWERS NEAR LAKE
SUPERIOR /EVEN IF IT IS JUST A SLIGHT CHANCE/...DESPITE THE STRONG
SURFACE HIGH STRETCHING FROM NORTHERN HUDSON BAY THROUGH ONTARIO AND
PORTIONS OF LAKE SUPERIOR THURSDAY NIGHT THROUGH SUNDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1237 PM EST MON FEB 25 2013
VFR CONDITIONS SHOULD PREVAIL THRU THE FCST PERIOD AT KIWD/KCMX...
THOUGH PROXIMITY OF LOWER CIGS JUST TO THE S AND SW MAY RESULT IN
MVFR CIGS DEVELOPING AT KIWD AND PERHAPS AT KCMX THIS AFTN/EVENING.
SHOULD SKIES CLEAR TONIGHT...FOG AND POSSIBLE IFR CONDITIONS COULD
DEVELOP AT KIWD/KCMX. AT KSAW...HIGH MVFR CIGS ARE LIKELY TO PREVAIL
INTO THE EVENING GIVEN UPSTREAM MVFR CIGS. IF CLOUDS SCATTER OUT
LATER TONIGHT...IFR CONDITIONS COULD ALSO DEVELOP AT KSAW.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 337 AM EST MON FEB 25 2013
A RIDGE OF HIGH PRESSURE JUST EAST OF LAKE SUPERIOR WILL REMAIN OVER
THE UPPER GREAT LAKES THROUGH TONIGHT. EXPECT LOW PRESSURE OVER THE
SOUTHERN PLAINS TO TRACK NORTHEAST ACROSS THE MID MISSISSIPPI VALLEY
ON TUESDAY...BEFORE STALLING OVER THE LOWER GREAT LAKES ON
WEDNESDAY. A PROLONGED PERIOD OF N TO NE WINDS CAN BE
EXPECTED...WITH WINDS OF 15 TO 30KTS TUESDAY INTO FRIDAY. A FEW GALE
FORCE GUSTS TO 35 KNOTS WILL BE POSSIBLE THURSDAY OVER MAINLY
CENTRAL LAKE SUPERIOR. THE LOW WILL THEN MOVE EAST THURSDAY THROUGH
FRIDAY AS HIGH PRESSURE OF NOSES SOUTHWARD INTO NORTHERN
ONTARIO...WITH LIGHTER WINDS TAKING HOLD.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...KF
AVIATION...ROLFSON
MARINE...KF
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
303 PM CST MON FEB 25 2013
.DISCUSSION...
A RATHER BENIGN FORECAST PERIOD IS AHEAD FOR THE LOCAL AREA...AS EYES
ARE FOCUSED TO THE SOUTH WITH THE POTENT WINTER STORM UNDERWAY.
FOR THE MPX CWA...THE PRIMARY CONCERNS THIS FORECAST PERIOD ARE
FOG TONIGHT AND SNOWFALL CHANCES FOR TOMORROW NIGHT INTO WEDNESDAY.
FOG AND LOW CLOUDS HAVE BEEN VERY SLOW TO ERODE TODAY...WITH THE
LIGHT WINDS AND LOITERING HIGH PRESSURE RIDGE FIRMLY IN PLACE.
HAVE FINALLY MADE SOME HEADWAY IN THE CLEARING THIS
AFTERNOON...BUT THINK FOG REDEVELOPMENT IS QUITE POSSIBLE AGAIN
TONIGHT...ESPECIALLY FROM CENTRAL INTO WEST CENTRAL MN WHERE
TEMP/DEWPOINT SPREADS ARE LOW AND WINDS WILL REMAIN LIGHT THROUGH
THE NIGHT. HAVE HIGHLIGHTED THE POTENTIAL FOR PATCHY DENSE FOG IN
THE HWO AND GRIDS...AND WILL MONITOR FOR THE POTENTIAL NEED FOR AN
ADVISORY THIS EVENING AS THE CLEARING EVOLVES.
ON TUESDAY...NORTHEAST WINDS INCREASE AS THE AFOREMENTIONED LOW
PRESSURE SYSTEM LIFTS ACROSS THE OH VALLEY. ON TUESDAY NIGHT INTO
WEDNESDAY...WEAK MID LEVEL ENERGY ON THE NORTHERN/WESTERN
PERIPHERY PIVOTS ACROSS CENTRAL WI AND SERN MN. WHILE THE LIFT AND
MOISTURE ARE MODEST...COULD BE SUFFICIENT TO SQUEEZE OUT A FEW
TENTHS OF AN INCH OF SNOW FROM NEAR ALBERT LEA TOWARD EAU
CLAIRE...WHERE SLIGHT CHANCE POPS HAVE BEEN INCLUDED FOR TUESDAY
NIGHT AND WEDNESDAY.
AFTER THAT...CHANCES FOR MEASURABLE SNOW REALLY DO NOT ARRIVE
UNTIL EARLY NEXT WEEK...AS A CLIPPER SYSTEM DIVES SOUTHEAST FROM
CANADA. THERE/S STILL A LARGE AMOUNT OF UNCERTAINTY WITH THE ROUTE
THIS TROUGH WILL TAKE...BUT WESTERN INTO SOUTH CENTRAL MN APPEARS
TO BE THE MORE FAVORED ROUTE FOR LIGHT SNOWFALL ON MONDAY INTO
TUESDAY.
TEMPERATURES WILL VARY LITTLE THROUGH THE FORECAST PERIOD...WITH
HIGHS GENERALLY FROM 25 TO 35...AND LOWS FROM 10 TO 25.
&&
.AVIATION.../18Z TAF ISSUANCE/
VERY COMPLICATED AVIATION FORECAST AS WINDS REMAIN NEARLY CALM UP
TO 500 METERS WHICH WILL LIMIT ANY MIXING. THE ONLY HELP THIS AFTN
IS THE HIGHER SUN ANGLE ALLOWING FOR BETTER ISOLATION WHICH WILL
LEAD TO SOME EROSION IN THE CLOUDS FROM TOP TO BOTTOM. REGIONAL
SATELLITE INDICATED THE BACK EDGE OF THE LOW CIGS ALONG THE ND/SD
BORDER WITH LITTLE MOVEMENT EASTWARD OVER THE PAST FEW HRS. BASED
ON THE LATEST RAP MIX LAYER UP TO 500 METERS...WINDS ARE NEARLY
CALM AS EXPLAINED BEFORE WITH A MORE SW ORIENTATION NORTH/NE OF
THE FA. A MORE N/NE FLOW ACROSS SW MN WHICH IS HAVING SOME AFFECTS
FROM THE STORM SYSTEM ACROSS THE SOUTH. THE MAIN DILEMMA IS
WHETHER TO SCATTER OUT THE CLOUD COVER THIS AFTN...AND TO LOWER
CIGS/VSBYS ONCE AGAIN OVERNIGHT IN THE TYPICAL AREAS IN THE MN
RIVER VALLEY TO AXN. ONE ITEM THAT DOES PLAY INTO THE FORECAST AFT
12Z TUE...IS THE INCREASING PRESSURE GRADIENT FROM THE STORM SYSTEM
TO THE SOUTH. EVENTUALLY THE PRESSURE GRADIENT WILL PRODUCE A MORE
EAST/NE FLOW TUE...AND ESPECIALLY TUE AFTN/EVENING. THIS WILL
ALLOW FOR MORE MIXING AND THE BETTER CHC OF VFR CONDS TO DEVELOP
AFT THIS TAF PERIOD. WILL CONTINUE PERSISTENCE WITH SOME VFR CONDS
DEVELOPING THIS AFTN AT AXN/RWF/STC. THIS COULD BE VERY SHORT
LIVED...OR EVEN NON-EXISTENT IF THE SUN ISOLATION IS NOT A FACTOR.
KMSP...
WILL CONTINUE THE MVFR CIGS THIS AFTN...WITH A POSSIBLE BREAK TO
VFR BY 00Z. CONFIDENCE IS LOW AS MIXING IN THE BOUNDARY LAYER IS
WEAK. EVENTUALLY WINDS WILL BECOME MORE E/NE LATE TONIGHT/TUESDAY
WHICH SHOULD BEGIN TO ERODE THE STAGNANT AIR MASS THAT HAS BEEN IN
PLACE OVER THE REGION. THE LATEST RAP/HOPWRF REMAINS VERY
PESSIMISTIC FOR THE MVFR CIGS TO CONTINUE WITH VSBYS ALSO
LOWERING OVERNIGHT. WILL CONTINUE THE SAME TREND WITH A PERIOD OF
VFR THIS EVENING...THEN BECOMING MVFR ONCE AGAIN AFT 6Z...WITH THE
POSSIBILITY OF VFR CONDS DEVELOPING AFT 18Z TUE. WINDS WILL BE
LIGHT AND VARIABLE THRU 6Z...WITH A MORE E/NE FLOW DEVELOPING
OVERNIGHT...AND BECOMING STRONGER FROM THE NE TUESDAY AFTN.
/OUTLOOK FOR KMSP/
WED...MVFR IN THE MORNING...THEN VFR. WINDS NNW 15KTS.
THU/FRI...VFR WITH MVFR CIGS POSSIBLE. WINDS N/NNE 5 TO 10KTS.
..JLT..
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
LS/JLT
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1126 AM CST MON FEB 25 2013
.DISCUSSION...
OVERVIEW...SNOWSTORM STILL ON TRACK FOR THE CENTRAL/SOUTHERN
PLAINS AND THE GREAT LAKES REGION OVER THE NEXT 48 HOURS. WE
REMAIN ON THE NORTHERN FRINGE FOR EVEN LIGHT SNOW AT THIS POINT.
BEST CHANCE FOR ANY SNOW REMAINS ACROSS PORTIONS OF WEST CENTRAL
WISCONSIN AND SOUTHEAST MINNESOTA TUESDAY NIGHT AND WEDNESDAY.
TEMPS WILL REMAIN NEAR CLIMATE NORMALS FOR THE NEXT SEVERAL DAYS.
WEAK 850-700MB WARM ADVECTION AND EVEN A SMALL AMOUNT OF FGEN IN
ROUGHLY THE SAME LAYER CONTRIBUTING TO THE LIGHT SNOW CURRENTLY
STRETCHING FROM EASTERN NE TO SOUTHWEST MN. MOST OF THIS IS
FALLING OUTSIDE OF THE FORECAST AREA...AND THERE IS EVEN LESS A
CHANCE FOR LIGHT SNOW AFTER 12Z. INCLUDED SCATTERED FLURRIES IN
WEST CENTRAL WI...BUT KEPT THE CHANCE FOR MEASURABLE UNDER 15%.
TEMPS THIS MORNING ARE BEING HELD IN CHECK DUE TO THE STEADY
STREAM OF MID AND HIGH CLOUDS FROM THE LOW CURRENTLY IN WESTERN
TEXAS...AND LOW CLOUDS THAT WERE ADVECTED INTO MN SUNDAY AFTERNOON
AND HAVE LINGERED SINCE. THE QUESTION IS IF AND OR WHEN DO WE
CLEAR OUT TODAY. INCLUDED FOG IN THE GRID IN WESTERN/NORTHERN
PORTIONS OF THE FORECAST AREA WHERE WE THINK THERE IS A BETTER
CHANCE OF BEING CLEAR TONIGHT. DEVELOPING INVERSION TONIGHT ALONG
HYDROLAPSE IN THE LOWEST 500 FT SUGGEST AREAS OF FOG ARE POSSIBLE.
THERE ARE A COUPLE SITES THIS MORNING REPORTING DENSE FOG AND WITH
A LITTLE MORE MELTING EXPECTED TODAY...FOG WILL REMAIN A PROBLEM
IF WE CLEAR OUT TONIGHT. THE GRADIENT REMAINS LIGHT OVER THE NEXT
18-24 HOURS...HOWEVER...AS THE SURFACE LOW LIFTS INTO SOUTHERN MO
LIGHT NORTHEAST WINDS ARE POSSIBLE BY 12Z TUESDAY ACROSS THE
SOUTHERN HALF OF THE CWA. NOT SURE THIS WILL BE ENOUGH TO
PROHIBIT FOG FORMATION.
IT`S FAIRLY CLEAR AFTER VIEWING THE GFS/NAM/ECMWF OVER THE PAST
FEW RUNS THAT THERE ISN`T MUCH CONCERN FOR SNOW IN THE FORECAST
AREA TUESDAY NIGHT AND WEDNESDAY. THE TREND HAS BEEN NEAR STEADY
TO A SLIGHT EASTWARD SHIFT WITH TIME. THE WEAK MID LEVEL
FRONTOGENESIS THAT HANGS BACK WELL WEST OF THE SURFACE LOW ISN`T
AS STRONG AS IT HAS LOOKED IN A COUPLE RUNS THIS PAST WEEKEND.
THE MAIN 500 MB LIFTS OUT OF THE PLAINS OVER THE NEXT 24
HOURS...BUT ANY HOPE FOR LIGHT SNOW HERE SEEMS TO REST WITH THE
SHORT WAVE NOW MOVING INLAND INTO WASHINGTON STATE AND BRITISH
COLUMBIA.
IN TERMS OF TEMPERATURES...REALLY STARTING TO SEE THE EFFECTS OF THE
ALBEDO DIFFERENCES ACROSS THE FORECAST AREA...WITH THE SNOW
COVERED PLAINS AND THE WOODED AREAS IN CENTRAL MN AND WI. EVEN THE
METRO AREAS ARE SHOWING UP AS MORE PRONOUNCED WARM SPOTS WITH THE
PROGRESSIVELY STRONGER LATE FEBRUARY SUNSHINE. THIS IS WHERE OUR
BIAS CORRECTED DATABASE TYPICALLY STARTS DOMINATING THE
VERIFICATION...BUT WE`LL HAVE TO WAIT FOR A MOSTLY SUNNY STRETCH
TO SEE THE FULL BENEFIT OF BIAS CORRECTED GRIDS AND WE MIGHT BE
FAIRLY CLOUDS THROUGH MID WEEK. HAVE TO ADMIT...NOT TERRIBLY
CONFIDENT WITH THE CURRENT SKY AND TEMP FORECAST IN THE COMING
DAYS. THERE IS SOME BUST POTENTIAL WITH THE HIGHS AND LOWS IN THE
COMING DAYS...FOR SUNNY DAYS IN OUR LOW ALBEDO AREAS AND CLEAR
NIGHTS WITH THE EXTENT OF OUR SNOW COVER.
&&
.AVIATION.../18Z TAF ISSUANCE/
VERY COMPLICATED AVIATION FORECAST AS WINDS REMAIN NEARLY CALM UP
TO 500 METERS WHICH WILL LIMIT ANY MIXING. THE ONLY HELP THIS AFTN
IS THE HIGHER SUN ANGLE ALLOWING FOR BETTER ISOLATION WHICH WILL
LEAD TO SOME EROSION IN THE CLOUDS FROM TOP TO BOTTOM. REGIONAL
SATELLITE INDICATED THE BACK EDGE OF THE LOW CIGS ALONG THE ND/SD
BORDER WITH LITTLE MOVEMENT EASTWARD OVER THE PAST FEW HRS. BASED
ON THE LATEST RAP MIX LAYER UP TO 500 METERS...WINDS ARE NEARLY
CALM AS EXPLAINED BEFORE WITH A MORE SW ORIENTATION NORTH/NE OF
THE FA. A MORE N/NE FLOW ACROSS SW MN WHICH IS HAVING SOME AFFECTS
FROM THE STORM SYSTEM ACROSS THE SOUTH. THE MAIN DILEMMA IS
WHETHER TO SCATTER OUT THE CLOUD COVER THIS AFTN...AND TO LOWER
CIGS/VSBYS ONCE AGAIN OVERNIGHT IN THE TYPICAL AREAS IN THE MN
RIVER VALLEY TO AXN. ONE ITEM THAT DOES PLAY INTO THE FORECAST AFT
12Z TUE...IS THE INCREASING PRESSURE GRADIENT FROM THE STORM SYSTEM
TO THE SOUTH. EVENTUALLY THE PRESSURE GRADIENT WILL PRODUCE A MORE
EAST/NE FLOW TUE...AND ESPECIALLY TUE AFTN/EVENING. THIS WILL
ALLOW FOR MORE MIXING AND THE BETTER CHC OF VFR CONDS TO DEVELOP
AFT THIS TAF PERIOD. WILL CONTINUE PERSISTENCE WITH SOME VFR CONDS
DEVELOPING THIS AFTN AT AXN/RWF/STC. THIS COULD BE VERY SHORT
LIVED...OR EVEN NON-EXISTENT IF THE SUN ISOLATION IS NOT A FACTOR.
KMSP...
WILL CONTINUE THE MVFR CIGS THIS AFTN...WITH A POSSIBLE BREAK TO
VFR BY 00Z. CONFIDENCE IS LOW AS MIXING IN THE BOUNDARY LAYER IS
WEAK. EVENTUALLY WINDS WILL BECOME MORE E/NE LATE TONIGHT/TUESDAY
WHICH SHOULD BEGIN TO ERODE THE STAGNANT AIR MASS THAT HAS BEEN IN
PLACE OVER THE REGION. THE LATEST RAP/HOPWRF REMAINS VERY
PESSIMISTIC FOR THE MVFR CIGS TO CONTINUE WITH VSBYS ALSO
LOWERING OVERNIGHT. WILL CONTINUE THE SAME TREND WITH A PERIOD OF
VFR THIS EVENING...THEN BECOMING MVFR ONCE AGAIN AFT 6Z...WITH THE
POSSIBILITY OF VFR CONDS DEVELOPING AFT 18Z TUE. WINDS WILL BE
LIGHT AND VARIABLE THRU 6Z...WITH A MORE E/NE FLOW DEVELOPING
OVERNIGHT...AND BECOMING STRONGER FROM THE NE TUESDAY AFTN.
/OUTLOOK FOR KMSP/
WED...MVFR IN THE MORNING...THEN VFR. WINDS NNW 15KTS.
THU/FRI...VFR WITH MVFR CIGS POSSIBLE. WINDS N/NNE 5 TO 10KTS.
..JLT..
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
CF/JLT
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
314 PM EST MON FEB 25 2013
.SYNOPSIS...
LAKE EFFECT CLOUDS AND SCATTERED FLURRIES THIS MORNING...MAINLY IN
CENTRAL NEW YORK...WILL YIELD TO BUILDING HIGH PRESSURE THIS
AFTERNOON. THIS WILL HELP BREAK UP THE CLOUDS LATER TODAY...AND
KEEP THINGS DRY AND QUIET TONIGHT THROUGH MOST OF TUESDAY.
HOWEVER...A MIX OF WINTRY PRECIPITATION IS LIKELY LATE TUESDAY
THROUGH EARLY WEDNESDAY AS LOW PRESSURE MOVES TOWARDS THE REGION
FROM THE OHIO VALLEY.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
1030 AM UPDATE... VSBL SAT ANIMATION INDICATES THAT CLDS ARE
HANGING TOUGH LATE THIS MRNG ACRS CNY/PTNS OF NE PA. THE LATEST
HI-RES NWP GUIDANCE STILL INDICATES THAT SOME DRYING WILL TAKE
PLACE DURG THE COURSE OF THE AFTN...SPCLY FROM THE TWIN TIERS SWD.
WE BLENDED IN THE LATEST RUC13 DATA...WHICH SEEMS TO HAVE A GOOD
HANDLE ON THE CURRENT EVOLUTION. ANY LINGERING FLRYS SHOULD BE
GONE BY 18-19Z.
BASED ON THE 12Z RAOBS AND WEAK ANTICIPATED THERMAL ADVECTION THIS
AFTN...OUR PRESENT HIGH TEMP FCST LOOKS GOOD...AND WAS ONLY
TWEAKED VERY SLIGHTLY.
PREV DISC... 630 AM UPDATE... GRIDS TWEAKED AS PER CURRENT
OBS...AND TO LINGER CLOUD COVER A BIT LONGER INTO THE AFTERNOON.
FORECAST GENERALLY ON TRACK...WITH ONLY SCATTERED FLURRIES
REMAINING DOWNWIND OF LAKE ONTARIO.
EARLIER DISCUSSION... ATMOSPHERIC COLUMN AS A WHOLE IS DRYING OUT...YET
MOISTURE REMAINS TRAPPED IN THE LOWEST FEW THOUSAND FEET AGL UNDER
A WEAK INVERSION. 850MB TEMPERATURES ARE ABOUT 9 OR 10 BELOW ZERO
CELSIUS...BARELY ENOUGH FOR THE WEAK LAKE RESPONSE OF SCATTERED
SNOW SHOWERS CURRENTLY DOWNWIND OF LAKE ONTARIO. WARM AIR
ADVECTION ALOFT WILL GRADUALLY RAISE 850MB TEMPERATURES HEADING
INTO THE DAY WHICH WILL ALLOW SNOW SHOWERS TO TAPER OFF TO A FEW
FLURRIES BEFORE ENDING. HOWEVER...STRATOCUMULUS WILL BE A BIT MORE
STUBBORN...ESPECIALLY CENTRAL NY. OVERALL...SUNSHINE WILL INCREASE
THROUGH THE DAY BUT WILL TAKE LONGER IN SOME PLACES THAN
OTHERS...AND HIGHS WILL BE RIGHT AROUND CLIMATOLOGICAL AVERAGES.
HIGH PRESSURE IN CHARGE TONIGHT FOR QUIET AND MOSTLY CLEAR
CONDITIONS. THE GOOD RADIATIONAL COOLING SET UP WILL YIELD MAINLY
LOWER 20S FOR LOWS...THOUGH SOME TEENS FOR THE MORE TYPICALLY
PRONE COLD AIR DRAINAGE VALLEYS. IN MANY CASES...AT OR SLIGHTLY
BELOW COLDEST MODEL GUIDANCE.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/...
500 AM UPDATE...
TUESDAY....FAIRLY GOOD AGREEMENT AMONGST THE MODELS WITH REGARDS
TO SYNOPTIC FEATURES WITH A DOMINANT SURFACE LOW AROUND 995 MB
TRACKING THROUGH CENTRAL INDIANA WITH A NEW LOW FORMING OVER NORTH
CENTRAL NC BY 0Z WEDNESDAY. THIS IS THE EASIEST PART OF THE
FORECAST WITH THICKENING CLOUDS AND PRECIP HOLDING OFF UNTIL LATE
IN THE DAY. LOOKING FOR ARRIVAL OF PRECIP TOWARD 23Z FAR SOUTH AND
WEST. MODEL PROFILES SHOW WARM SURFACE TEMPS SO INITIAL SHOT OF
PRECIP COULD BE IN THE FORM OF SNOW...SLEET OR PLAIN RAIN.
TUESDAY NIGHT...UNCERTAINTY IS THE KEY WORD FOR THIS PART OF THE
FORECAST. DESPITE GOOD MODEL AGREEMENT WITH THE SYNOPTIC
PLAYERS...SUBTLE DIFFERENCES IN TEMP PROFILES GIVE US THE WHOLE
RANGE OF P-TYPE POSSIBILITIES DURING THE NIGHT. IF THAT WERE NOT
ENOUGH QPF AMOUNTS ARE ALSO HIGHER VARIABLE. WILL TACKLE EACH
ISSUE SEPARATELY FOR NOW.
P TYPE...THE EURO REMAINS THE COLDEST OF ALL MODELS SHOWING A
MOSTLY SNOW EVENT FOR MOST OF THE CWA UNTIL CLOSER TO DAYBREAK
WHEN WARMER AIR AROUND 850 MB MAKES ITS WAY INTO THE POCONOS.
MEANWHILE THE GFS AND NAM ARE FAIRLY SIMILAR IN THAT THEY SHOW A
TONGUE OF WARMER AIR AROUND 850 MB MOVE IN. THAT WOULD IMPLY ANY
SNOW WOULD EVENTUALLY MIX WITH SLEET/FREEZING RAIN AND PLAIN
RAIN. A FEW ITEMS THAT WE WILL BE WATCHING. THIS LAYER OF WARMER
AIR ALOFT MAY BE ABLE TO BE OVERCOME FOR A PERIOD DURING THE NIGHT
WHEN LIFT IS MAXIMIZED AND DYNAMIC COOLING ALLOWS FOR A SWITCH
OVER TO ALL SNOW. WITH TEMP PROFILES SO CLOSE..THIS MAY BE JUST
ENOUGH...ESPECIALLY OVER THE HIGHER TERRAIN OF THE CATSKILLS AND
WESTERN SOUTHERN TIER FOR A PERIOD OF HEAVIER SNOW. HOWEVER...IF THE NAM
AND GFS ARE CORRECT WITH THIS WARMER LAYER ALOFT...FREEZING RAIN
POTENTIAL WILL HAVE TO BE WATCHED CAREFULLY. MOST MODEL SOUNDINGS
SHOW SURFACE TEMPS NEAR OR BELOW FREEZING FROM ABOUT 04Z THROUGH
12Z...WITH MODEL QPFS AROUND A HALF OF AN INCH. CONFIDENCE HOWEVER
IN THIS ICE POTENTIAL IS LOW GIVEN THE MODEL UNCERTAINTY WITH
P-TYPE. IN ADDITION THOSE MODELS THAT SUGGEST THE WARMER LAYER
ALOFT...ALSO SHOW A FAIRLY DEEP LAYER OF COLDER AIR BELOW THIS WARM
NOSE WHICH WOULD SUGGEST PROLONGED SLEET VERSUS FREEZING RAIN. IF
THE FREEZING RAIN DOES PAN OUT...THE POSITION OF THE SURFACE HIGH
OVER NOVA SCOTIA WOULD GIVE US MORE OF AN EASTERLY COMPONENT TO
THE SURFACE WIND WHICH MAY NOT LOCK IN THE COLD AIR AS MUCH FOR
THE MAJORITY OF THE CWA...ASIDE FROM THE MOHAWK VALLEY WHERE IT IS
IDEAL. WITH SO MUCH UNCERTAINTY PLAYED THE GRIDS TO SHOW THIS.
PLAYED A WINTRY MIX FOR MOST OF THE AREA THROUGH THE NIGHT. BOTH
THE EURO/NAM/AND GFS DO SHOW WARMER AIR MOVING INTO NEPA SO HERE I
REMOVED THE MENTION OF SNOW OR SLEET IN THE WYOMING VALLEY TOWARD
12Z WITH ICE REMAINING IN THE POCONOS. WOULD LOVE TO BE MORE
SPECIFIC BUT SOMETIMES WE JUST DON`T KNOW THIS FAR OUT YET AND DO
NOT WANT TO CONVEY THAT WE KNOW THE EXACT P-TYPES THAT WILL FALL.
QPF...THE NAM APPEARS TO BE WAY OVERDONE WITH QPF WITH VALUES OF
BETWEEN .75" AND AN INCH BY 12Z WEDNESDAY. THE EURO IS ABOUT HALF
THAT OR AROUND A HALF OF AN INCH...WITH THE SREFS AND GFS IN THE
MIDDLE (.50-.75). PER COORDINATION WITH THE OTHER OFFICES DECIDED
TO HOLD OFF ON ANY WATCHES WITH TOO MUCH UNCERTAINTY REGARDING
P-TYPE.
WEDNESDAY....SURFACE COLD AIR MAY REMAIN ACROSS THE MOHAWK VALLEY
AND PARTS OF SULLIVAN COUNTY WITH THE EASTERLY FLOW...OTHERWISE
WARM BOUNDARY LAYER TEMPS SUPPORT A CHANGE TO MOSTLY RAIN DURING
THE DAY. TOWARD 0Z AS COLDER AIR MOVES IN FROM THE WEST SOME WET
SNOW IS POSSIBLE. STILL SOME UNCERTAINTY HERE HOWEVER GIVEN THE
EURO IS MUCH COLDER AND WOULD SUPPORT SNOW THROUGHOUT MOST OF THE DAY.
WILL STICK WITH CONTINUITY FROM THE PREVIOUS FORECAST AS IT IS
SUPPORTED BY THE GFS AND NAM...ALONG WITH MAIN SURFACE LOW TRACK
BEING TO OUR WEST AND NOT A FAVORABLE POSITION OF THE SURFACE
HIGH FOR ALL SNOW.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
XTNDD PD DOMINATED BY A MEANDERING UPR LVL LOW AND COOL AIR. LOW
INITIALLY DRIFTS EAST EARLY IN THE PD...BUT IS REPLACED BY A
SCNDRY LOW WHICH ROTATES BACK AROUND TROF INTO THE AREA. GFS IS A
BIT MORE PROGRESSIVE THRU THE PD BUT WLD STILL KEEP THE AREA IN A
NLY FLOW WITH DEEP MOISTURE. THERE/S NOT ANY STRONG LIFT WITH THE
UPR LOW SO PCPN WILL BE LGT...BUT PERSISTENT. ALSO...TEMPS UNDER
THE LOW SLOWLY MODIFY...WITH THE ECMWF BEING COOLER MAINTAINING
THE UPR TROF. GNRLY FLWD THE HPC GUID THRU THE PD WHICH WAS CLOSER
TO THE ECMWF...HWVR...DID ADJUST SLGTLY WRMR FOR COLLABORATION
AND TO EDGE TWRD THE GFS.
&&
.AVIATION /20Z MONDAY THROUGH SATURDAY/...
18Z MON UPDATE... LWR CLDS (MVFR CIGS AT MOST SITES) WILL PERSIST
THROUGH THIS EVE. LTR TNT (GENERALLY IN THE 03-09Z TIME
FRAME)...SOME DRIER AIR AT LWR LVLS SHOULD BUILD IN...WITH
CLEARING SKIES ANTICIPATED AT THAT TIME.
VFR SHOULD THEN HOLD FOR THE REMAINDER OF THE VALID TAF PD (18Z
TUE). THE NEXT ROUND OF WINTRY PCPN SHOULD HOLD OFF TIL LATE IN
THE DAY TUE...OR EARLY IN THE EVE (22Z OR LATER).
N TO NW WINDS 5-10 KT THIS AFTN...WILL TURN LGT AND VRBL
TNT...BEFORE SHIFTING INTO THE SE TUE AM AT 5-10 KT.
.OUTLOOK...
TUE NGT/WED MRNG...MVFR TO IFR LIKELY...WITH A WINTRY MIX OF PCPN
TYPES (SNOW/SLEET/FRZG RAIN).
WED AFTN THRU FRI...RESTRICTIONS ARE LIKELY TO CONTINUE...WITH PDS
OF LIGHT RAIN OR SNOW.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MDP
NEAR TERM...MLJ/MDP
SHORT TERM...HEDEN
LONG TERM...DGM
AVIATION...MLJ
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1206 PM EST MON FEB 25 2013
.SYNOPSIS...
LAKE EFFECT CLOUDS AND SCATTERED FLURRIES THIS MORNING...MAINLY IN
CENTRAL NEW YORK...WILL YIELD TO BUILDING HIGH PRESSURE THIS
AFTERNOON. THIS WILL HELP BREAK UP THE CLOUDS LATER TODAY...AND
KEEP THINGS DRY AND QUIET TONIGHT THROUGH MOST OF TUESDAY.
HOWEVER...A MIX OF WINTRY PRECIPITATION IS LIKELY LATE TUESDAY
THROUGH EARLY WEDNESDAY AS LOW PRESSURE MOVES TOWARDS THE REGION
FROM THE OHIO VALLEY.
&&
.NEAR TERM /THROUGH TONIGHT/...
1030 AM UPDATE... VSBL SAT ANIMATION INDICATES THAT CLDS ARE
HANGING TOUGH LATE THIS MRNG ACRS CNY/PTNS OF NE PA. THE LATEST
HI-RES NWP GUIDANCE STILL INDICATES THAT SOME DRYING WILL TAKE
PLACE DURG THE COURSE OF THE AFTN...SPCLY FROM THE TWIN TIERS SWD.
WE BLENDED IN THE LATEST RUC13 DATA...WHICH SEEMS TO HAVE A GOOD
HANDLE ON THE CURRENT EVOLUTION. ANY LINGERING FLRYS SHOULD BE
GONE BY 18-19Z.
BASED ON THE 12Z RAOBS AND WEAK ANTICIPATED THERMAL ADVECTION THIS
AFTN...OUR PRESENT HIGH TEMP FCST LOOKS GOOD...AND WAS ONLY
TWEAKED VERY SLIGHTLY.
PREV DISC... 630 AM UPDATE... GRIDS TWEAKED AS PER CURRENT
OBS...AND TO LINGER CLOUD COVER A BIT LONGER INTO THE AFTERNOON.
FORECAST GENERALLY ON TRACK...WITH ONLY SCATTERED FLURRIES
REMAINING DOWNWIND OF LAKE ONTARIO.
EARLIER DISCUSSION... ATMOSPHERIC COLUMN AS A WHOLE IS DRYING OUT...YET
MOISTURE REMAINS TRAPPED IN THE LOWEST FEW THOUSAND FEET AGL UNDER
A WEAK INVERSION. 850MB TEMPERATURES ARE ABOUT 9 OR 10 BELOW ZERO
CELSIUS...BARELY ENOUGH FOR THE WEAK LAKE RESPONSE OF SCATTERED
SNOW SHOWERS CURRENTLY DOWNWIND OF LAKE ONTARIO. WARM AIR
ADVECTION ALOFT WILL GRADUALLY RAISE 850MB TEMPERATURES HEADING
INTO THE DAY WHICH WILL ALLOW SNOW SHOWERS TO TAPER OFF TO A FEW
FLURRIES BEFORE ENDING. HOWEVER...STRATOCUMULUS WILL BE A BIT MORE
STUBBORN...ESPECIALLY CENTRAL NY. OVERALL...SUNSHINE WILL INCREASE
THROUGH THE DAY BUT WILL TAKE LONGER IN SOME PLACES THAN
OTHERS...AND HIGHS WILL BE RIGHT AROUND CLIMATOLOGICAL AVERAGES.
HIGH PRESSURE IN CHARGE TONIGHT FOR QUIET AND MOSTLY CLEAR
CONDITIONS. THE GOOD RADIATIONAL COOLING SET UP WILL YIELD MAINLY
LOWER 20S FOR LOWS...THOUGH SOME TEENS FOR THE MORE TYPICALLY
PRONE COLD AIR DRAINAGE VALLEYS. IN MANY CASES...AT OR SLIGHTLY
BELOW COLDEST MODEL GUIDANCE.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
500 AM UPDATE...
TUESDAY....FAIRLY GOOD AGREEMENT AMONGST THE MODELS WITH REGARDS
TO SYNOPTIC FEATURES WITH A DOMINANT SURFACE LOW AROUND 995 MB
TRACKING THROUGH CENTRAL INDIANA WITH A NEW LOW FORMING OVER NORTH
CENTRAL NC BY 0Z WEDNESDAY. THIS IS THE EASIEST PART OF THE
FORECAST WITH THICKENING CLOUDS AND PRECIP HOLDING OFF UNTIL LATE
IN THE DAY. LOOKING FOR ARRIVAL OF PRECIP TOWARD 23Z FAR SOUTH AND
WEST. MODEL PROFILES SHOW WARM SURFACE TEMPS SO INITIAL SHOT OF
PRECIP COULD BE IN THE FORM OF SNOW...SLEET OR PLAIN RAIN.
TUESDAY NIGHT...UNCERTAINTY IS THE KEY WORD FOR THIS PART OF THE
FORECAST. DESPITE GOOD MODEL AGREEMENT WITH THE SYNOPTIC
PLAYERS...SUBTLE DIFFERENCES IN TEMP PROFILES GIVE US THE WHOLE
RANGE OF P-TYPE POSSIBILITIES DURING THE NIGHT. IF THAT WERE NOT
ENOUGH QPF AMOUNTS ARE ALSO HIGHER VARIABLE. WILL TACKLE EACH
ISSUE SEPARATELY FOR NOW.
P TYPE...THE EURO REMAINS THE COLDEST OF ALL MODELS SHOWING A
MOSTLY SNOW EVENT FOR MOST OF THE CWA UNTIL CLOSER TO DAYBREAK
WHEN WARMER AIR AROUND 850 MB MAKES ITS WAY INTO THE POCONOS.
MEANWHILE THE GFS AND NAM ARE FAIRLY SIMILAR IN THAT THEY SHOW A
TONGUE OF WARMER AIR AROUND 850 MB MOVE IN. THAT WOULD IMPLY ANY
SNOW WOULD EVENTUALLY MIX WITH SLEET/FREEZING RAIN AND PLAIN
RAIN. A FEW ITEMS THAT WE WILL BE WATCHING. THIS LAYER OF WARMER
AIR ALOFT MAY BE ABLE TO BE OVERCOME FOR A PERIOD DURING THE NIGHT
WHEN LIFT IS MAXIMIZED AND DYNAMIC COOLING ALLOWS FOR A SWITCH
OVER TO ALL SNOW. WITH TEMP PROFILES SO CLOSE..THIS MAY BE JUST
ENOUGH...ESPECIALLY OVER THE HIGHER TERRAIN OF THE CATSKILLS AND
WESTERN SOUTHERN TIER FOR A PERIOD OF HEAVIER SNOW. HOWEVER...IF THE NAM
AND GFS ARE CORRECT WITH THIS WARMER LAYER ALOFT...FREEZING RAIN
POTENTIAL WILL HAVE TO BE WATCHED CAREFULLY. MOST MODEL SOUNDINGS
SHOW SURFACE TEMPS NEAR OR BELOW FREEZING FROM ABOUT 04Z THROUGH
12Z...WITH MODEL QPFS AROUND A HALF OF AN INCH. CONFIDENCE HOWEVER
IN THIS ICE POTENTIAL IS LOW GIVEN THE MODEL UNCERTAINTY WITH
P-TYPE. IN ADDITION THOSE MODELS THAT SUGGEST THE WARMER LAYER
ALOFT...ALSO SHOW A FAIRLY DEEP LAYER OF COLDER AIR BELOW THIS WARM
NOSE WHICH WOULD SUGGEST PROLONGED SLEET VERSUS FREEZING RAIN. IF
THE FREEZING RAIN DOES PAN OUT...THE POSITION OF THE SURFACE HIGH
OVER NOVA SCOTIA WOULD GIVE US MORE OF AN EASTERLY COMPONENT TO
THE SURFACE WIND WHICH MAY NOT LOCK IN THE COLD AIR AS MUCH FOR
THE MAJORITY OF THE CWA...ASIDE FROM THE MOHAWK VALLEY WHERE IT IS
IDEAL. WITH SO MUCH UNCERTAINTY PLAYED THE GRIDS TO SHOW THIS.
PLAYED A WINTRY MIX FOR MOST OF THE AREA THROUGH THE NIGHT. BOTH
THE EURO/NAM/AND GFS DO SHOW WARMER AIR MOVING INTO NEPA SO HERE I
REMOVED THE MENTION OF SNOW OR SLEET IN THE WYOMING VALLEY TOWARD
12Z WITH ICE REMAINING IN THE POCONOS. WOULD LOVE TO BE MORE
SPECIFIC BUT SOMETIMES WE JUST DON`T KNOW THIS FAR OUT YET AND DO
NOT WANT TO CONVEY THAT WE KNOW THE EXACT P-TYPES THAT WILL FALL.
QPF...THE NAM APPEARS TO BE WAY OVERDONE WITH QPF WITH VALUES OF
BETWEEN .75" AND AN INCH BY 12Z WEDNESDAY. THE EURO IS ABOUT HALF
THAT OR AROUND A HALF OF AN INCH...WITH THE SREFS AND GFS IN THE
MIDDLE (.50-.75). PER COORDINATION WITH THE OTHER OFFICES DECIDED
TO HOLD OFF ON ANY WATCHES WITH TOO MUCH UNCERTAINTY REGARDING
P-TYPE.
WEDNESDAY....SURFACE COLD AIR MAY REMAIN ACROSS THE MOHAWK VALLEY
AND PARTS OF SULLIVAN COUNTY WITH THE EASTERLY FLOW...OTHERWISE
WARM BOUNDARY LAYER TEMPS SUPPORT A CHANGE TO MOSTLY RAIN DURING
THE DAY. TOWARD 0Z AS COLDER AIR MOVES IN FROM THE WEST SOME WET
SNOW IS POSSIBLE. STILL SOME UNCERTAINTY HERE HOWEVER GIVEN THE
EURO IS MUCH COLDER AND WOULD SUPPORT SNOW THROUGHOUT MOST OF THE DAY.
WILL STICK WITH CONTINUITY FROM THE PREVIOUS FORECAST AS IT IS
SUPPORTED BY THE GFS AND NAM...ALONG WITH MAIN SURFACE LOW TRACK
BEING TO OUR WEST AND NOT A FAVORABLE POSITION OF THE SURFACE
HIGH FOR ALL SNOW.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
130 PM UPDATE...
AS FRONT MVS THRU ON WEDNESDAY, CWA WL BE UNDER THE INFLUENCE OF H5
LOW CLOSING OFF ACRS NERN U.S. MED RANGE GUIDANCE CONTS TO SUGGEST
THIS WL HAPPEN BY MID-WEEK AND EVENTUALLY HEAD EAST LATE IN THE
WEEK (PER 00Z/12Z EURO) OR HANG OUT THRU THE WEEKEND (PER 12Z GFS).
MAIN DIFFERENCES CNTR AROUND H5 HEIGHTS BEGINNING LATE IN THE
WEEK WITH EURO DROPPING WAVE INTO THE INTERMOUNTAIN WEST WHILE GFS
IS QUICKER WITH THIS WV AND MVS IT INTO THE DAKOTAS AT 12Z
THURSDAY. BY 00Z FRIDAY, ECMWF APPEARS TO TREAT IT AS A KICKER AND
KICKS THE UL TO THE EAST. GFS ALLOWS THIS WV TO GET ABSORBED AS IT
DROPS INTO THE TN VLY AND JUST RE-INTENSIFIES THE LOW OVR TOP OF
US. THE LATEST GFS IS QUITE A CHG FM ITS 06Z RUN AS IT APPEARED TO
BE IN LOCK-STEP WITH ECMWF. THUS, HV FOLLOWED 12Z EURO DUE TO ITS
CONSISTENCY WITH THE 00Z RUN.
EITHER WAY, SCTD POPS EXPECTED FM THURSDAY ON IN ONE FORM OR
ANOTHER, GENERALLY A RAIN/SNOW SHOWER MIX DRG THE DAYLIGHT HOURS
AND SNOW SHOWERS AT NIGHT. GIVEN THE EXTENSIVE CLD CVR EXPECTED
AND NW FLOW WORKING IN, TEMPS WL BE FAIRLY STEADY THRU THE PD WITH
ONLY A DEGREE OR TWO CHANGE BTWN THE OVRNGT LOWS AND AFTN HIGHS.
&&
.AVIATION /18Z MONDAY THROUGH FRIDAY/...
18Z MON UPDATE... LWR CLDS (MVFR CIGS AT MOST SITES) WILL PERSIST
THROUGH THIS EVE. LTR TNT (GENERALLY IN THE 03-09Z TIME
FRAME)...SOME DRIER AIR AT LWR LVLS SHOULD BUILD IN...WITH
CLEARING SKIES ANTICIPATED AT THAT TIME.
VFR SHOULD THEN HOLD FOR THE REMAINDER OF THE VALID TAF PD (18Z
TUE). THE NEXT ROUND OF WINTRY PCPN SHOULD HOLD OFF TIL LATE IN
THE DAY TUE...OR EARLY IN THE EVE (22Z OR LATER).
N TO NW WINDS 5-10 KT THIS AFTN...WILL TURN LGT AND VRBL
TNT...BEFORE SHIFTING INTO THE SE TUE AM AT 5-10 KT.
.OUTLOOK...
TUE NGT/WED MRNG...MVFR TO IFR LIKELY...WITH A WINTRY MIX OF PCPN
TYPES (SNOW/SLEET/FRZG RAIN).
WED AFTN THRU FRI...RESTRICTIONS ARE LIKELY TO CONTINUE...WITH PDS
OF LIGHT RAIN OR SNOW.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MDP
NEAR TERM...MLJ/MDP
SHORT TERM...HEDEN
LONG TERM...PVN
AVIATION...MLJ
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1255 PM EST MON FEB 25 2013
.SYNOPSIS...
NORTH OF A DEVELOPING WARM FRONT...MOISTURE WILL SPREAD ATOP OUR
REGION FROM THE GULF OF MEXICO. STRONG LOW PRESSURE WILL DRIVE
A COLD FRONT ACROSS OUR AREA ON TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
930 AM UPDATE...HIGH TEMPS HAVE BEEN LOWERED A FEW DEGREES. CAD
WEDGE AND THICK CIRRUS DECK HAVE KEPT TEMPS COOLER THAN PREV FCST SO
FAR TODAY. LATEST AVBL MOS GUIDANCE AS WELL AS RAW MODEL TEMPS KEPT
PRACTICALLY ALL OF THE CWA IN THE 40S THROUGH THE DAY. FEEL THIS IS
APPROPRIATE. AS FOR PRECIP...LATEST RAP INDICATES A WAVE OF PRECIP
EARLY THIS AFTN THEN A LULL BEFORE WARM FRONTAL PRECIP TONIGHT.
DISCOUNTING THIS AS MODEL CONSENSUS IS FOR STEADILY INCREASING LLVL
ISENTROPIC FORCING FROM AFTN INTO EVENING...THUS OUR STEADILY
INCREASING POPS LOOK GOOD.
PREVIOUS DISCUSSION...
A WELL DEFINED ULVL CONFLUENT ZONE HAS SET UP ACROSS THE NE CONUS
WHICH IS ALLOWING A 1025 MB OH VALLEY SFC HIGH TO RIDGE EAST AND
SOUTH INTO THE REGION. MEANWHILE...AN H5 S/W IS CROSSING TO THE
SOUTH AND BRINGING IN A WIDE AREA OF CI. THIS SCENARIO IS CAPTURED
WELL BY THE OP MODELS ALONG WITH A DEEPENING H5 CUTOFF LOW PROGGED
TO MOVE INTO THE SRN MS RIVER VALLEY THROUGH THE PERIOD.
A FAIRLY STRONG WEDGE WILL DEVELOP TODAY WHILE MOISTURE FLUX OFF
BOTH THE GOM AND THE ATL ADVECT INTO THE AREA. CROSS SECTIONS ARE
PRETTY CONSISTENT ON THE GFS/NAM/SREF WITH THE DEEPER MOISTURE AND
ISENT OMEGA REACHING THE SRN ZONES AROUND 00Z AND SPREADING PRECIP
OVER THE ENTIRE CWFA QUICKLY THROUGH 03Z. POPS WERE ADJ DOWN EARLY
FOR A SOMEWHAT LATER ONSET TIME...BUT ALL AREAS SHOULD BE AT OR NEAR
100 POP BY 06Z THROUGH THE PERIOD.
THERE IS NOT A LOT OF COOLING NOR LOW TD/S ASSOCIATED WITH THIS
WEDGE...SO PRECIP TYPES OVERNIGHT WILL REMAIN RAIN AT ALL
LOCALES...EXCEPT FOR THE HIGHER TERRAIN OF THE BLACK MTNS AND THE
NRN MTNS WHERE PERIODS -FZRA WILL DEVELOP IN DIURNAL COOLING. MOST
OF THESE LOCATIONS WONT SEE SIGFNT ICE ACCUMS...BUT ISOLATED PEAKS
AROUND BEECH MTN COULD SEE A COUPLE TENTHS OF ICE AS THEY WILL
EXPERIENCE THE LONGEST PERIOD OF ICING BEFORE LLVL WAA CHANGES ALL
PRECIP TO RAIN. RAINFALL AMOUNTS OVERNIGHT WILL BE FAIRLY UNIFORM
ACROSS THE NC ZONES...AROUND AN INCH...AND UP TO AN INCH AND A HALF
ACROSS THE SRN ZONES AND NE GA. THIS WONT CREATE ANY FLOODING
CONCERN DUE TO THE 12 HR TIMEFRAME...BUT ADDITIONAL RAINFALL THROUGH
TUE MAY BEGIN TO ELEVATE SMALL STREAM AND CREEK LEVELS.
ANOTHER ISSUE WITH THIS SYSTEM WILL BE THE HIGHLY DYNAMIC OCCLUDED
SFC LOW TO THE WEST AND THE STRENGTHENING SFC RIDGE EAST. THIS WILL
SET UP A RATHER STRONG P/GRAD...BUT THE SFC WINDS WONT BECOME OVERLY
GUSTY WITH THE STRONGER VELOCITIES REMAINING ABOVE THE WEDGE
INVERSION. THE HIGHER ELEVATIONS OF THE WRN NC MTNS WILL LIKELY SEE
A SE/LY MTN WAVE SET UP AND DAMAGING WIND GUSTS FORCED TO THE SFC.
THE MODELS ARE SHOWING VERY GOOD ISENT DECENT AND RELATIVELY DEEP
NEG OMEGA AFT 06Z ALIGNED WITH WIND SPEEDS OF 55 KTS ABOVE 3.5 K
FEET. BASED ON GOOD CONFIDENCE WITH THIS IMPENDING SCENARIO...A HIGH
WIND WARNING WILL BE ISSUED FOR THE WRN NC MTNS ABOVE 3.5 K.
MAX TEMPS TODAY WILL BE ON THE COOL SIDE WITH WEDGE AND CLOUD COVER.
BLENDED THE OFFICIAL FCST WITH LOWER END METMOS GUIDANCE...WHICH
GAVE MAXES IN THE L50S NON/MTNS...AND U40S MTN VALLEYS. CONTINUED
NE/LY FLOW AND COOLER AIR ALOFT GUSTING TO THE SFC...YET HIGH CLOUD
COVER...LOWS SHOULD DROP TO RIGHT AROUND NORMAL.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 330 AM EST MONDAY...THE SHORT RANGE WILL BE DOMINATED BY THE
PASSAGE OF A LARGE AND DYNAMIC UPPER LOW MOVING FROM THE MID MS
VALLEY...UP THE OH VALLEY...TO THE LOWER GREAT LAKES THROUGH THE
PERIOD. THE MAIN ACTION WILL BE TUESDAY...WITH A CLASSIC COLD AIR
DAMMING WEDGE IN PLACE AT SUNRISE WITH PRECIP FALLING ACROSS NEARLY
THE ENTIRE FCST AREA. THERE ARE MANY CONCERNS. HIGH WIND POTENTIAL
WILL REMAIN HIGH ALONG THE TN BORDER SO THE HIGH WIND WARNING WILL
BE RUN THROUGH NOON. ANY LINGERING PRECIP TYPE ISSUES NEAR THE BLUE
RIDGE OVER THE NRN MTNS AND NRN FOOTHILLS SHOULD GO AWAY QUICKLY
AFTER SUNRISE WITH TEMPS WARMING ABOVE FREEZING. HEAVY RAIN IS ONE
OF THE PRIMARY CONCERNS...AND THE OTHER IS SEVERE WEATHER. MUCH OF
THIS WILL DEPEND ON THE TRACK OF A TRIPLE POINT LOW. THE LATEST
MODEL GUIDANCE SHOWS THIS FEATURE MOVING ACROSS THE MIDDLE OF SC AND
NC...OFF TO OUR EAST...DURING THE DAY. THIS WOULD TEND TO DECREASE
THE HEAVY RAIN THREAT OVER THE MTNS AND BLUE RIDGE ALONG THE SC/NC
BORDER. PW ANOMALIES ARE NOT OVERLY HIGH EITHER. WILL NOT ISSUE A
FLOOD WATCH AT THIS TIME OWING TO THE DOWNWARD QPF TREND. AS FOR THE
SEVERE WEATHER...IF THE TRIPLE POINT LOW TAKES A MORE WESTWARD TRACK
AS SHOWN BY THE NAM...WE COULD GET THE SRN/ERN PARTS OF METRO CLT
INTO THE WARMER AIR ON THE COASTAL SIDE OF THE WEDGE BOUNDARY IN THE
LATE AFTERNOON...WHICH WOULD INCREASE THE THREAT FOR SEVERE STORMS.
FOR NOW...WILL INCLUDE SOME THUNDER IN THE FCST THERE.
THE PRECIP SHOULD EXIT THE REGION DURING THE LATE AFTERNOON AND
EARLY EVENING ON TUESDAY...AFTER WHICH ANY LINGERING POP IS
RELEGATED TO THE MTNS...MOSTLY NEAR THE TN BORDER. THE MAIN CULPRIT
WILL BE WRAP-AROUND SHOWERS THROUGH TUESDAY NIGHT AND INTO
WEDNESDAY. THE LOW LEVEL FLOW REMAINS SW INITIALLY AND IS ONLY
SLOWLY EXPECTED TO COME AROUND TO W AND THEN NW WEDNESDAY NIGHT.
THUS...PRECIP POTENTIAL WILL GRADUALLY IMPROVE WEDNESDAY NIGHT AS
COLDER AIR MOVES IN TO CHANGE THE P-TYPE TO SNOW TOWARD DAYBREAK ON
THURSDAY. SOME ACCUM SHOULD BE EXPECTED ON THE TN BORDER...AND THIS
IS EXPECTED TO CONTINUE INTO THE MEDIUM RANGE.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 230 AM MONDAY...A DEEPENING LOW PRES SYSTEM WILL CONSOLIDATE
OVER WRN PA/NY EARLY THU. THERE IS GOOD MODEL CONSENSUS ON THE
LOCATION AND DEPTH OF THIS MAJOR FEATURE EARLY ON...BUT THEN VARYING
SOLUTIONS ON ADDITIONAL ENERGY PIVOTING AROUND THE LOW AND CROSSING
THE REGION FRI THROUGH SUN.
AS THE LOW SLOWLY DEPARTS PA AND NY AREA TO THE EAST THURS THROUGH
FRI...LOW LEVEL MOISTURE WILL BE IN PLACE OVER EAST TN UP AGAINST
THE NC MTNS. THIS MOISTURE WILL BE DEEPEST IN THIS MEDIUM RANGE
PERIOD ON THURS AND GRADUALLY DECREASE DEPENDING ON THE MODEL
REFERENCED INTO THE WEEKEND. 850MB TEMPS OVER THE MTNS WILL RANGE
FROM -5 TO -7C AT 12Z THURS BEING SLIGHTLY COLDEST IN THE ECMWF.
THESE 850MB TEMPS WARM A DEGREE OR TWO INTO FRI AND THEN COLDER
THROUGH THE WEEKEND DOWN TO -8 TO -11C 12Z SUNDAY. ALONG WITH THE
DEEPEST MOISTURE ON THURSDAY...THE WIND IS FORECAST TO BE FROM THE
WNW. AS THE LOW MOVES EAST ALONG WITH MORE SHALLOW MOISTURE...THE
WIND BECOMES NW WHICH IS MOST FAVORABLE FOR UPSLOPE SNOW SHOWERS.
SOME SHORTWAVE ENERGY ROUNDS THE BASE OF THE TROUGH LATE FRIDAY
ENHANCING THE UPSLOPE SNSH. ANOTHER SPOKE OF ENERGY CROSSES SAT PM
AND THE ECMWF CONTINUES TO HAVE A CUT OFF LOW WHICH KICKS OFF LIGHT
PRECIP OVER ALL OF THE WESTERN CAROLINAS AND NORTH GA SAT PM. THE
GFS HAS SOME PRECIP OVER NRN GA AND UPSTATE AND THE CMC LAYS OUT A
BROADER TROUGH AND SMALLER AMOUNTS OF SPOTTY PRECIP. THE UPPER
TROUGH AXIS IF FORECAST TO CROSS OUR AREA LATE SUNDAY. EXPECT MINS 5
TO 10 DEGREES BELOW NORMAL...WITH MAXES 10 TO 15 DEGREES BELOW
NORMAL...THROUGH THE PERIOD.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
AT KCLT...CIRRUS CIG THIS AFTN WILL BEGIN TO LOWER BY LATE AFTN AS
ISENTROPIC LIFT OVER COLD SFC WEDGE RAMPS UP. LOW VFR LOOKS TO SET
IN BY ABOUT 01Z FOLLOWED BY RAPID LOWERING TO IFR CIG WITH ONSET OF
RAINFALL THAT WILL CONTINUE THROUGH THE END OF THE PERIOD. GUIDANCE
SUGGESTS MVFR VSBY WILL ACCOMPANY THE RAIN BUT FOG NOT EXPECTED WITH
NEAR SFC AIR REMAINING DRY. WINDS REMAIN NE TO ENE UNDER THE WEDGE
GRADUALLY INCREASING IN STRENGTH AS SFC LOW ENTERS OHIO VALLEY.
APPROACHING COLD FRONT WILL LIKELY SCOUR OUT THE WEDGE...TURN WINDS
SWLY AND END THE PRECIP...BUT CURRENT TIMING HAS THIS OCCURRING
AFTER 18Z.
ELSEWHERE...VFR CIGS THIS AFTN WILL LOWER FROM SOUTH TO NORTH AS
WARM FRONT/ISENTROPIC LIFT INCREASES AHEAD OF APPROACHING SFC LOW.
FAR SOUTHERN PART OF THE FCST AREA EXPECTED TO SEE MVFR CIG BY
AROUND SUNSET WHEN PRECIP SHOULD ALSO BEGIN. PRECIP WILL SPREAD
NORTHWARD ACROSS ALL SITES OVERNIGHT PEAKING IN COVERAGE AROUND
SUNRISE. RAIN WILL LIKELY LOWER VSBY TO MVFR...AND THOUGH SFC TEMPS
MAY REMAIN JUST ABOVE FREEZING IN THE MTNS SOME SNOW/SLEET MAY MIX
WITH THE RAIN THERE LATE TONIGHT. GUIDANCE GIVING FAIRLY STRONG
SIGNAL OF WIDESPREAD IFR CIGS ACROSS THE AREA FORMING AROUND 09Z.
THIS IS LIKELY TO LAST UNTIL COLD FRONT WORKS INTO THE REGION FROM
THE WEST NEAR THE END OF THE PERIOD. KAVL MAY SEE LIFTING TO VFR
JUST BEFORE 18Z. WINDS WILL REMAIN IN NE QUADRANT AT ALL SITES UNTIL
THE FRONT MOVES THROUGH...AGAIN THE ONLY SITE AFFECTED IS KAVL.
OUTLOOK...CLEARING SKIES ARE IN STORE TUESDAY NIGHT WITH VFR
EXPECTED THROUGH THURSDAY EAST OF THE MOUNTAINS. SOME POTENTIAL FOR
MVFR ACROSS THE NC MTNS WITH SNOW SHOWERS MID TO LATE WEEK.
CONFIDENCE TABLE...
18-24Z 00-06Z 06-12Z 12-18Z
KCLT HIGH 100% HIGH 100% MED 72% HIGH 93%
KGSP HIGH 100% HIGH 81% MED 62% HIGH 89%
KAVL HIGH 100% HIGH 87% HIGH 83% HIGH 80%
KHKY HIGH 100% HIGH 100% MED 75% HIGH 89%
KGMU HIGH 100% MED 79% MED 62% HIGH 89%
KAND HIGH 100% MED 75% MED 77% HIGH 93%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...HIGH WIND WARNING FROM MIDNIGHT TONIGHT TO 6 PM EST TUESDAY
FOR NCZ033-048>052-058-059.
WIND ADVISORY FROM MIDNIGHT TONIGHT TO 6 PM EST TUESDAY FOR
NCZ033-048>052-058-059.
SC...NONE.
&&
$$
SYNOPSIS...DEO
NEAR TERM...SBK/WIMBERLEY
SHORT TERM...PM
LONG TERM...DEO
AVIATION...WIMBERLEY
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
350 PM CST MON FEB 25 2013
.DISCUSSION...
POWERFUL WINTER STORM CONTINUES TO MOVE THROUGH THE SOUTHERN
PLAINS THIS AFTERNOON RESULTING IN PRIMARILY A WIND EVENT ACROSS
NORTH TEXAS...BUT SOME WINTRY WEATHER IS EXPECTED THROUGH THIS
EVENING FOR PARTS OF THE AREA. LATEST SURFACE ANALYSIS SHOWS THE
CENTER OF THE SURFACE LOW NEAR EL DORADO ARKANSAS WHERE 3 HOUR
PRESSURE FALLS ARE IN EXCESS OF 7MB. PRESSURE FALLS EXTEND ALL THE
WAY WESTWARD TOWARD WICHITA FALLS WHERE A SURFACE TROUGH HAS
PERSISTED ALL DAY. THESE PERSISTENT PRESSURE FALLS ARE AN
INDICATION THAT THE ENTIRE UPPER STORM SYSTEM IS DEEPENING. WATER
VAPOR IMAGERY SHOWS A WELL DEFINED CIRCULATION WHICH APPEARS TO
NOW BE MOVING DUE EAST TOWARD THE BEST SURFACE PRESSURE FALLS.
THIS IS CONCERNING BECAUSE SUBSTANTIAL WRAP AROUND PRECIPITATION
DRIVEN BY FRONTOGENETICAL FORCING WILL LIKELY TRACK FARTHER SOUTH
THAN EARLIER ANTICIPATED. SHORT TERM HIGH RESOLUTION GUIDANCE
APPEARS TO HAVE SOMEWHAT OF A HANDLE ON THE MOVEMENT OF THE UPPER
SYSTEM BUT PRECIPITATION IS QUICKLY ERODED DUE TO STRONG
SUBSIDENCE. MESOSCALE FRONTOGENETICAL FORCING IS LIKELY TO WIN OUT
AT LEAST FOR A FEW HOURS ON THE BACK SIDE OF THE SYSTEM RESULTING
IN PRECIPITATION ACROSS MAINLY THE NORTHWEST COUNTIES THROUGH MIDNIGHT.
CONCERNING THE PRECIPITATION...FORECAST SOUNDINGS FROM BOTH THE
HIGH RES 3KM TTU WRF AND RAP MODEL SUGGEST THAT THE THERMAL
PROFILE WILL BE SUFFICIENTLY COLD FOR SNOWFALL PRODUCTION
GENERALLY NORTH OF INTERSTATE 20 THROUGH LATE TONIGHT...DESPITE
THE WARM SURFACE TEMPERATURES. INITIAL CONVECTIVE SHOWERS
NORTHEAST OF THE METROPLEX SHOULD REMAIN ALL LIQUID. GIVEN THE
POTENTIAL FOR SNOWFALL...ALONG WITH STRONG GUSTY WINDS...HAVE
ISSUED A SHORT DURATION WINTER WEATHER ADVISORY FOR THE FAR
NORTHWEST COUNTIES THROUGH MIDNIGHT. WITH WARM GROUND TEMPERATURES
AND GENERALLY ABOVE FREEZING SURFACE TEMPERATURES...EXPECT ANY
ACCUMULATIONS TO BE CONFINED TO GRASSY SURFACES. THE PRIMARY
CONCERN WILL BE FOR BLOWING SNOW WHICH COULD REDUCE VISIBILITY TO
LESS THAN 1/2 MILE AT TIMES. ROADS SHOULD REMAIN IN GOOD SHAPE.
THE OTHER MAIN CONCERN IS WINDS THROUGH LATE TONIGHT. WITH THE
CENTER OF THE SURFACE LOW NEARBY FOR MUCH OF THE AFTERNOON...WINDS
HAVE GENERALLY BEEN HIGHEST ACROSS THE SOUTHERN COUNTIES WHERE
GUSTS TO 54 MPH HAVE BEEN REPORTED. WITH THE SURFACE LOW NOW
MOVING EAST...THE PRESSURE GRADIENT WILL CONTINUE TO TIGHTEN
THROUGH EVENING. THE STRONGEST LOW LEVEL JET WILL BE CENTERED
ACROSS THE AREA RIGHT AROUND MIDNIGHT SO IT APPEARS THAT THE
STRONGEST WINDS ACROSS MUCH OF THE REGION ARE STILL TO COME.
ONE LIMITING FACTOR TO STRONGER WINDS WILL BE THE FACT THAT IT
WILL BE NIGHT WHEN THE STRONGEST WINDS ALOFT ARE OVERHEAD. THE CURRENT
WIND ADVISORY WILL REMAIN IN EFFECT THROUGH 4 AM FOR ALL OF NORTH
TEXAS.
WITH THE ENTIRE SYSTEM MOVING TO THE NORTHEAST TOMORROW...SKIES
SHOULD CLEAR AND WINDS WILL DIMINISH. A COUPLE OF REINFORCING
FRONTS...ONE ON WEDNESDAY AND ANOTHER LATE THURSDAY NIGHT...WILL
KEEP TEMPERATURES COOL THROUGH THE WEEK. NO SIGNIFICANT CHANGES TO
THE EXTENDED FORECAST AS IT APPEARS THAT IT WILL REMAIN DRY
THROUGH THE PERIOD.
DUNN
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 35 54 34 54 34 / 20 5 0 0 5
WACO, TX 35 61 34 60 33 / 5 0 0 0 5
PARIS, TX 36 49 31 51 31 / 40 5 0 0 5
DENTON, TX 35 53 30 51 31 / 30 5 0 0 5
MCKINNEY, TX 36 52 32 51 32 / 30 5 0 0 5
DALLAS, TX 37 56 35 55 35 / 20 5 0 0 5
TERRELL, TX 36 52 34 54 34 / 10 5 0 0 5
CORSICANA, TX 37 57 35 58 34 / 5 0 0 0 5
TEMPLE, TX 36 63 36 63 33 / 5 0 0 0 5
MINERAL WELLS, TX 34 57 30 54 29 / 40 0 0 0 5
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 4 AM CST TUESDAY FOR TXZ091>095-100>107-
115>123-129>135-141>148-156>162-174-175.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR TXZ091-
100-101-115.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS AMARILLO TX
1157 AM CST MON FEB 25 2013
.AVIATION...
FOR THE 18Z TAFS...AN AVIATION WEATHER WARNING REMAINS IN EFFECT FOR
KAMA AND TRADEWIND AIRPORT THROUGH 00Z TONIGHT DUE TO STRONG GUSTY WINDS.
SNOW...BLOWING SNOW...AND GUSTY WINDS WILL BE THE PRIMARY FOCUS
THROUGH EARLY EVENING. SNOW HAS STOPPED AT KDHT...WITH THE
POSSIBILITY FOR BLOWING SNOW THROUGH 21Z AS WINDS REMAIN GUSTY TO
45KTS. CEILINGS SHOULD CONTINUE TO IMPROVE THROUGH 03Z WHEN SKIES
WILL CLEAR
AT KAMA AND KGUY...SNOW AND BLOWING SNOW CONTINUE TO REDUCE
VISIBILITY BELOW 1 MILE...WITH KAMA VSBY AT 1/4SM TO 1/2SM WHILE SNOW
REMAINS HEAVY. SNOW SHOULD TAPER OFF BY 00Z. IFR CEILINGS SLOWLY
IMPROVING TO MVFR CEILINGS BY 21Z TO 00Z...BEFORE CLEARING AFTER 03Z.
NF
&&
.PREV DISCUSSION... /ISSUED 1057 AM CST MON FEB 25 2013/
UPDATE...
MADE MINOR ADJUSTMENTS TO THE SNOW AMOUNT GRIDS FROM NOON TO 6 PM TO
ACCOUNT FOR HIGHER SNOWFALL RATES AS THE UPPER LOW LIFTS TO THE NORTH
AND EAST. DURING THIS TIME FRAME 3 TO 6 ADDITIONAL INCHES OF SNOW
WILL BE POSSIBLE ACROSS THE EASTERN OKLAHOMA AND TEXAS PANHANDLE AND
THE SOUTH CENTRAL TEXAS PANHANDLE.
PREV DISCUSSION... /ISSUED 833 AM CST MON FEB 25 2013/
.CRIPPLING BLIZZARD ROARS ON...
UPDATE...
GOING FORECAST STILL ON TRACK. THE NWS OFFICE NOW HAS OVER 13 INCHES
ON THE GROUND WITH 3-4 FOOT DRIFTS AND A MAX GUST TO 58 MPH. THE SE
TX PANHANDLE HAS BEEN SLOW TO FILL IN WITH SNOW AFTER THE
THUNDERSTORMS THAT DROPPED HEAVY RAIN LAST NIGHT AND THESE AREAS
MIGHT END UP WITH AMOUNTS CLOSER TO THE 8 INCH SIDE THAN THE 14 INCH
SIDE OF THEIR RANGE. AT THE END OF THE DAY...THE HEAVIEST TOTALS
WILL ALMOST CERTAINLY BE ALONG A PALO DURO CANYON TO AMARILLO TO
STINNETT TO PERRYTON LINE.
SOME RECORDS SEEM TO BE IN A PRECARIOUS POSITION TODAY. THE FIRST IS
AN ALL-TIME 24 HOUR SNOWFALL RECORD AT AMARILLO OF 20.6 INCHES FROM
MARCH 25-26 1934. WE WILL LIKELY GET VERY CLOSE OR SURPASS THIS
NUMBER BY THIS AFTERNOON.
THE OTHER IS THE ALL-TIME STATE OF TEXAS 24 HOUR SNOWFALL RECORD OF
25 INCHES IN FOLLETT SET MARCH 28 2009. SOMEWHERE IN THE
PERRYTON/STINNETT/BORGER/AMARILLO AREA COULD APPROACH THIS VALUE BY
THIS AFTERNOON.
SIMPSON
PREV DISCUSSION... /ISSUED 541 AM CST MON FEB 25 2013/
AVIATION.../12Z TAFS/
VERY HAZARDOUS FLYING CONDITIONS EXPECTED TO CONTINUE THROUGH AT
LEAST 00Z AT ALL TERMINALS. HEAVIEST SNOW AND LOWEST VISIBILITIES
WILL BE AT KAMA 15-20Z. AWW REMAINS IN EFFECT FOR KAMA AND TRADEWINDS
AIRPORT UNTIL 00Z.
VFR CONDITIONS ARE EXPECTED TO RETURN TO ALL TERMINALS 00-02Z.
NW WINDS ARE EXPECTED TO SUBSIDE BELOW 12 KT AT ALL TERMINALS BY 04Z.
JACKSON
PREV DISCUSSION... /ISSUED 446 AM CST MON FEB 25 2013/
SNOW PILING UP...WINDS INCREASING AND CREATING FULL FLEDGED BLIZZARD
CONDITIONS AT THIS WRITING...
DISCUSSION...
MAIN CHANGE TO PREVIOUS FORECAST WAS TO ATTEMPT TO PIN POINT THE BAND
OF HIGHEST SNOW TOTALS...WHICH WILL LIKELY STRETCH ALONG AN ARC FROM
TULIA TO AMARILLO TO STINNETT TO SPEARMAN. LOCATIONS ON THIS ARC AND
30 MILES TO THE EAST AND WEST OF IT ARE SET TO RECEIVE AT LEAST A
FOOT OF SNOW...WITH TOTALS UP TO 2 FEET NOT COMPLETELY OUT OF THE
QUESTION. THE REST OF THE PANHANDLES WILL SEE SLIGHTLY LESSER
AMOUNTS...BUT STILL BLIZZARD CONDITIONS. SEE THE BLIZZARD WARNING AND
GRAPHICS ON WFO AMA HOMEPAGE AND FACEBOOK FOR A BETTER REPRESENTATION
OF THIS EVENT THAN CAN BE TYPED IN BLOCK TEXT.
THE NAM AND RUC HAVE DONE A GOOD JOB IN SHOWING A STRONG BAND OF
FRONTOGENETICAL FORCING...THOUGH THE PLACEMENT HAS BEEN TOO FAR EAST.
THIS BAND HAS SET UP OVER THE AFOREMENTIONED ARC AND CONVECTIVE
ENHANCEMENT WITH RATES TO 2-3 INCHES PER HOUR HAVE BEEN NOTED. IN
FACT...WE HAVE OBSERVED AT LEAST A HALF DOZEN CLOUD TO GROUND
STRIKES AT THE NWS AMA OFFICE OVERNIGHT...WITH ABOUT 6 INCHES
ALREADY ON THE GROUND AS OF 4 AM. INTENSE MESOSCALE BANDING SHOULD
PERSIST INTO THE MORING HOURS AND POSSIBLY INTO THE AFTERNOON...
THOUGH RATES WILL LIKELY SUBSIDE A BIT AFTER 18Z.
WINDS...
DOWNWARD MOMENTUM TRANSFER/MIXING OF A DEVELOPING 60-70KT LLJ WILL
RESULT IN FREQUENT GUSTS ABOVE 50 MPH AND POTENTIALLY A FEW GUSTS TO
65 MPH. THE WORST OF THE WINDS WILL OCCUR FROM 12-22Z TODAY.
ALL-IN-ALL...THE WELL ADVERTISED BLIZZARD IS COMING TO FRUITION
FOR THE VAST MAJORITY OF THE PANHANDLES. THE ONLY LOCATIONS THAT
WILL SEE REDUCED SNOWFALL AMOUNTS WILL BE THE FAR NW PANHANDLES...BUT
VERY STRONG WINDS WILL BLOW AROUND ANY MINOR SNOWFALL ACCUMULATIONS
AND STILL CREATE BRIEF BLIZZARD CONDITIONS.
TUESDAY THROUGH SUNDAY...
A COLD AND MAINLY DRY PERIOD WILL BE NOTED UNDER PREDOMINATELY NORTH
WINDS. A FEW WEAK UPR WAVES COULD KICK OFF A FLURRY TUE NIGHT AND
AGAIN THU...BUT NOTHING APPRECIABLE IS EXPECTED. WINDS MIGHT FINALLY
SWING AROUND TO THE SOUTH SAT NIGHT AND SUN...BUT QUICKLY COME BACK
TO THE NORTH BEHIND ANOTHER COLD FRONT ON SUNDAY NIGHT.
SIMPSON
FIRE WEATHER...
ELEVATED OR CRITICAL FIRE WEATHER CONDITIONS ARE NOT EXPECTED
THROUGH NEXT GIVEN THE EXPECTED SNOW COVER.
SIMPSON
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...BLIZZARD WARNING UNTIL 3 AM CST TUESDAY FOR THE FOLLOWING ZONES:
ARMSTRONG...CARSON...COLLINGSWORTH...DALLAM...DEAF SMITH...
DONLEY...GRAY...HANSFORD...HARTLEY...HEMPHILL...
HUTCHINSON...LIPSCOMB...MOORE...OCHILTREE...OLDHAM...
POTTER...RANDALL...ROBERTS...SHERMAN...WHEELER.
OK...BLIZZARD WARNING UNTIL 3 AM CST TUESDAY FOR THE FOLLOWING ZONES:
BEAVER...CIMARRON...TEXAS.
&&
$$
06/14
AREA FORECAST DISCUSSION
NWS AMARILLO TX
1057 AM CST MON FEB 25 2013
.UPDATE...
MADE MINOR ADJUSTMENTS TO THE SNOW AMOUNT GRIDS FROM NOON TO 6 PM TO
ACCOUNT FOR HIGHER SNOWFALL RATES AS THE UPPER LOW LIFTS TO THE NORTH
AND EAST. DURING THIS TIME FRAME 3 TO 6 ADDITIONAL INCHES OF SNOW
WILL BE POSSIBLE ACROSS THE EASTERN OKLAHOMA AND TEXAS PANHANDLE AND
THE SOUTH CENTRAL TEXAS PANHANDLE.
&&
.PREV DISCUSSION... /ISSUED 833 AM CST MON FEB 25 2013/
..CRIPPLING BLIZZARD ROARS ON...
UPDATE...
GOING FORECAST STILL ON TRACK. THE NWS OFFICE NOW HAS OVER 13 INCHES
ON THE GROUND WITH 3-4 FOOT DRIFTS AND A MAX GUST TO 58 MPH. THE SE
TX PANHANDLE HAS BEEN SLOW TO FILL IN WITH SNOW AFTER THE
THUNDERSTORMS THAT DROPPED HEAVY RAIN LAST NIGHT AND THESE AREAS
MIGHT END UP WITH AMOUNTS CLOSER TO THE 8 INCH SIDE THAN THE 14 INCH
SIDE OF THEIR RANGE. AT THE END OF THE DAY...THE HEAVIEST TOTALS
WILL ALMOST CERTAINLY BE ALONG A PALO DURO CANYON TO AMARILLO TO
STINNETT TO PERRYTON LINE.
SOME RECORDS SEEM TO BE IN A PRECARIOUS POSITION TODAY. THE FIRST IS
AN ALL-TIME 24 HOUR SNOWFALL RECORD AT AMARILLO OF 20.6 INCHES FROM
MARCH 25-26 1934. WE WILL LIKELY GET VERY CLOSE OR SURPASS THIS
NUMBER BY THIS AFTERNOON.
THE OTHER IS THE ALL-TIME STATE OF TEXAS 24 HOUR SNOWFALL RECORD OF
25 INCHES IN FOLLETT SET MARCH 28 2009. SOMEWHERE IN THE
PERRYTON/STINNETT/BORGER/AMARILLO AREA COULD APPROACH THIS VALUE BY
THIS AFTERNOON.
SIMPSON
PREV DISCUSSION... /ISSUED 541 AM CST MON FEB 25 2013/
AVIATION.../12Z TAFS/
VERY HAZARDOUS FLYING CONDITIONS EXPECTED TO CONTINUE THROUGH AT
LEAST 00Z AT ALL TERMINALS. HEAVIEST SNOW AND LOWEST VISIBILITIES
WILL BE AT KAMA 15-20Z. AWW REMAINS IN EFFECT FOR KAMA AND TRADEWINDS
AIRPORT UNTIL 00Z.
VFR CONDITIONS ARE EXPECTED TO RETURN TO ALL TERMINALS 00-02Z.
NW WINDS ARE EXPECTED TO SUBSIDE BELOW 12 KT AT ALL TERMINALS BY 04Z.
JACKSON
PREV DISCUSSION... /ISSUED 446 AM CST MON FEB 25 2013/
SNOW PILING UP...WINDS INCREASING AND CREATING FULL FLEDGED BLIZZARD
CONDITIONS AT THIS WRITING...
DISCUSSION...
MAIN CHANGE TO PREVIOUS FORECAST WAS TO ATTEMPT TO PIN POINT THE BAND
OF HIGHEST SNOW TOTALS...WHICH WILL LIKELY STRETCH ALONG AN ARC FROM
TULIA TO AMARILLO TO STINNETT TO SPEARMAN. LOCATIONS ON THIS ARC AND
30 MILES TO THE EAST AND WEST OF IT ARE SET TO RECEIVE AT LEAST A
FOOT OF SNOW...WITH TOTALS UP TO 2 FEET NOT COMPLETELY OUT OF THE
QUESTION. THE REST OF THE PANHANDLES WILL SEE SLIGHTLY LESSER
AMOUNTS...BUT STILL BLIZZARD CONDITIONS. SEE THE BLIZZARD WARNING AND
GRAPHICS ON WFO AMA HOMEPAGE AND FACEBOOK FOR A BETTER REPRESENTATION
OF THIS EVENT THAN CAN BE TYPED IN BLOCK TEXT.
THE NAM AND RUC HAVE DONE A GOOD JOB IN SHOWING A STRONG BAND OF
FRONTOGENETICAL FORCING...THOUGH THE PLACEMENT HAS BEEN TOO FAR EAST.
THIS BAND HAS SET UP OVER THE AFOREMENTIONED ARC AND CONVECTIVE
ENHANCEMENT WITH RATES TO 2-3 INCHES PER HOUR HAVE BEEN NOTED. IN
FACT...WE HAVE OBSERVED AT LEAST A HALF DOZEN CLOUD TO GROUND
STRIKES AT THE NWS AMA OFFICE OVERNIGHT...WITH ABOUT 6 INCHES
ALREADY ON THE GROUND AS OF 4 AM. INTENSE MESOSCALE BANDING SHOULD
PERSIST INTO THE MORING HOURS AND POSSIBLY INTO THE AFTERNOON...
THOUGH RATES WILL LIKELY SUBSIDE A BIT AFTER 18Z.
WINDS...
DOWNWARD MOMENTUM TRANSFER/MIXING OF A DEVELOPING 60-70KT LLJ WILL
RESULT IN FREQUENT GUSTS ABOVE 50 MPH AND POTENTIALLY A FEW GUSTS TO
65 MPH. THE WORST OF THE WINDS WILL OCCUR FROM 12-22Z TODAY.
ALL-IN-ALL...THE WELL ADVERTISED BLIZZARD IS COMING TO FRUITION
FOR THE VAST MAJORITY OF THE PANHANDLES. THE ONLY LOCATIONS THAT
WILL SEE REDUCED SNOWFALL AMOUNTS WILL BE THE FAR NW PANHANDLES...BUT
VERY STRONG WINDS WILL BLOW AROUND ANY MINOR SNOWFALL ACCUMULATIONS
AND STILL CREATE BRIEF BLIZZARD CONDITIONS.
TUESDAY THROUGH SUNDAY...
A COLD AND MAINLY DRY PERIOD WILL BE NOTED UNDER PREDOMINATELY NORTH
WINDS. A FEW WEAK UPR WAVES COULD KICK OFF A FLURRY TUE NIGHT AND
AGAIN THU...BUT NOTHING APPRECIABLE IS EXPECTED. WINDS MIGHT FINALLY
SWING AROUND TO THE SOUTH SAT NIGHT AND SUN...BUT QUICKLY COME BACK
TO THE NORTH BEHIND ANOTHER COLD FRONT ON SUNDAY NIGHT.
SIMPSON
FIRE WEATHER...
ELEVATED OR CRITICAL FIRE WEATHER CONDITIONS ARE NOT EXPECTED
THROUGH NEXT GIVEN THE EXPECTED SNOW COVER.
SIMPSON
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...BLIZZARD WARNING UNTIL 3 AM CST TUESDAY FOR THE FOLLOWING ZONES:
ARMSTRONG...CARSON...COLLINGSWORTH...DALLAM...DEAF SMITH...
DONLEY...GRAY...HANSFORD...HARTLEY...HEMPHILL...
HUTCHINSON...LIPSCOMB...MOORE...OCHILTREE...OLDHAM...
POTTER...RANDALL...ROBERTS...SHERMAN...WHEELER.
OK...BLIZZARD WARNING UNTIL 3 AM CST TUESDAY FOR THE FOLLOWING ZONES:
BEAVER...CIMARRON...TEXAS.
&&
$$
99/14
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1059 AM CST MON FEB 25 2013
.SHORT TERM...UPDATE THROUGH THIS AFTERNOON
1031 AM CST MON FEB 25 2013
WATER VAPOR SATELLITE IMAGERY SHOWS A MID-LEVEL TROUGH PUSHING
EAST ACROSS MN AT THIS TIME. RAP SHOWING SOME WEAK ISENTROPIC
UPGLIDE ON THE 285K SURFACE BETWEEN 850-750MB INTO THIS AFTERNOON
MAINLY ACROSS NORTHEAST IA INTO SOUTHWEST WI IN RESPONSE TO THIS WAVE.
PERIODIC/VERY LIGHT SNOW FALLING IN RESPONSE TO THIS LIFT WITH
CHARLES CITY IA REPORTING A VERY LIGHT DUSTING THIS PAST HOUR.
HAVE ADJUSTED FORECAST ACCORDINGLY TO REFLECT THIS SCENARIO INTO
THE AFTERNOON HOURS.
.LONG TERM...THURSDAY THROUGH SUNDAY
320 AM CST MON FEB 25 2013
AFTER THE SYSTEM MOVES OFF TO THE EAST COAST BY MID WEEK...A BROAD
RIDGE OF HIGH PRESSURE WILL EXTEND DOWN FROM NORTH CENTRAL CANADA
DOWN TO THE GULF COAST AND REMAIN ACROSS THE UPPER MISSISSIPPI
RIVER VALLEY REGION INTO NEXT WEEKEND. WHILE THE LOW TO UPPER
LEVEL FLOW WILL BE OUT OF THE NORTH...THERE IS NOT MUCH OF A COLD
SOURCE TO PULL FROM OUT OF CENTRAL CANADA...SO TEMPERATURES SHOULD
NOT TAKE MUCH OF A HIT THROUGH THE WEEK. CLEARING SKIES AND AN
INCREASING SUN ANGLE WILL HELP AS WELL TO KEEP TEMPERATURES NEAR
NORMAL.
&&
.AVIATION...THROUGH 18Z TUESDAY
1058 AM CST MON FEB 25 2013
FAIRLY DIFFICULT FORECAST THROUGH THE NEXT 24 HOURS WITH REGARD
TO LOW CLOUD/FOG POTENTIAL. CURRENTLY THERE IS A MID-LEVEL WAVE
PUSHING EAST ACROSS THE AREA AND THIS HAS BEEN RESPONSIBLE FOR
SOME PERIODIC VERY LIGHT SNOW IN WEAK ISENTROPIC UPGLIDE.
OTHERWISE...VIS/3.9MICRON IMAGERY SURFACE OBSERVATIONS SHOWING
QUITE A BIT OF IFR/LIFR STRATUS AND FOG OUT ACROSS SOUTH CENTRAL
MN/WESTERN IA. EASTERN PERIPHERY OF THIS WAS UNCOMFORTABLY CLOSE
TO KRST TAF SITE. THINKING WITH THE SURFACE RIDGE AXIS LAYING UP
W-E ACROSS THE AREA INTO THIS EVENING ALONG WITH PARTIAL
SNOWMELT LOADING THE LOWER BOUNDARY LAYER WITH ADDITIONAL
MOISTURE...POTENTIAL IS SETTING UP FOR SOME IFR/LIFR CONDITIONS AT
LEAST ACROSS SOUTHEAST MN INCLUDING THE KRST TAF SITE. DON/T THINK
THAT KLSE WILL BE AS BAD AND PLANNING ON CARRYING MVFR CONDITIONS
GOING INTO THIS EVENING. LOW PRESSURE SYSTEM MOVING ACROSS THE
SOUTHERN PLAINS INTO THE BOOTHEEL REGION OF MO OVERNIGHT WILL
BRING AN INCREASING/DRIER LOW LEVEL FLOW INTO THE AREA AFTER
MIDNIGHT AND THINKING THAT THIS WILL IMPROVE CONDITIONS INTO VFR
RANGE. WILL TAKE A CLOSER LOOK AT EVERYTHING BEFORE SENDING OUT
FINALIZED 18Z TAFS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
320 AM CST MON FEB 25 2013
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM....HALBACH
AVIATION...DAS