Forecast Discussions mentioning any of
"HRRR" "RR" "RUC13" "RUC" received at GSD on 02/11/12
AREA FORECAST DISCUSSION
NWS DENVER CO
1259 PM MST THU FEB 9 2012
.UPDATE...MORE CLOUDS UPSTREAM MOVING ACROSS PLAINS...NEEDED TO
UPDATE SKY GRIDS. RADAR SHOWING ALOT OF ECHOES ACROSS THE
PLAINS...APPEARS NOTHING HITTING GROUND AT THIS TIME. WILL NOT
INCLUDE POPS AT THIS POINT.
&&
.AVIATION...LOTS OF STRATOCU ACROSS PLAINS. CEILINGS HAVE DROPPED
TO AROUND 4500-5500 AGL. HAVE UPDATED DIA TAF AS A
RESULT. KEPT THE BROKEN LAYER THROUGH 23Z AS SUGGESTED BY LATEST
FORECAST SOUNDINGS. SHOULD SEE THINGS BECOMING SCATTERED AFTER 00Z.
&&
.PREV DISCUSSION... /ISSUED 1056 AM MST THU FEB 9 2012/
UPDATE...SHORTWAVE CURRENTLY PASSING ACROSS AREA...STILL QUITE A
BIT OF CLOUDS ACROSS MUCH OF CFWA. WEB CAMS AND RADAR LOOPS
SHOWING PERSISTANT LIGHT SNOW OVER THE MOUNTAINS...MAINLY ALONG
THE CONTINENTAL DIVIDE. DESPITE SUBSIDENCE THIS AFTERNOON BEHIND
EXITING SHORTWAVE...BOTH NAM AND RUC STILL KEEP QUITE A BIT OF
CLOUD OVER THE MOUNTAINS...ALONG WITH LIGHT QPF/SNOW AMOUNTS ALONG
THE DIVIDE. BASED ON THE CURRENT TRENDS...WILL NEED TO KEEP A
CHANCE OF SNOW OVER THE HIGHER PEAKS THROUGH MUCH OF THE
AFTERNOON. OTHERWISE...TREND TOWARD DECREASING CLOUDS STILL
LOOKING ON TRACK FOR NOW. REST OF FORECAST TRENDS ALSO ON TRACK.
AVIATION...CURRENT TAF TRENDS SEEM ON TRACK...DID KEEP THE BROKEN
MID LEVEL A BIT LONGER. LATEST NAM AND GFS GUIDANCE SHOWING A
BROKEN 6000-7000 AGL DECK THROUGH 21Z. NOT SURE IF THIS WILL PAN
OUT BASED ON AREA OBSERVATIONS. A BIT OF STRATUS TOWARDS CASPER
WITH SOME LIGHT SNOW...DON`T THINK IT WILL PUSH INTO COLORADO ANY
TIME SOON.
PREV DISCUSSION... /ISSUED 400 AM MST THU FEB 9 2012/
SHORT TERM...WEAK SHORTWAVE MOVING ACROSS COLORADO THIS MORNING.
MOISTURE WILL BE DIMINISHING FROM THE NORTHWEST THOUGH A FEW SNOW
SHOWERS MAY HANG ON INTO THE AFTERNOON IN THE HIGH MOUNTAINS. NOT A
LOT OF TEMPERATURE ADVECTION WITH THIS TROUGH...A WARMER START TO
THE DAY AND A BIT MORE MIXING AS A RESULT...SO WILL TRY AGAIN FOR A
WARMER DAY OVER THE PLAINS. WE WILL LIKELY SEE THE SAME TEMPERATURE
PATTERN HOWEVER...JUST NOT AS EXTREME. STILL NEED TO DROP FORECAST
HIGHS ON THE PLAINS...UNDERCUTTING MOS GUIDANCE IN MOST AREAS DUE TO
THE SNOW COVER. MOSTLY CLEAR SKIES THIS EVENING THEN SOME INCREASE
IN CLOUD COVER POSSIBLE AGAIN TOWARD MORNING. COOLED LOWS IN THE
MOUNTAIN VALLEYS...BUT NOT AS MUCH AS GUIDANCE SINCE THERE IS STILL
SOME MOISTURE AND PROBABLY SOME CLOUD COVER AGAIN TOWARD MORNING.
LONG TERM...NORTHWESTERLY FLOW ALOFT IS PROGGED FRIDAY INTO FRIDAY
NIGHT. THEN AN UPPER RIDGE MOVES ACROSS THROUGH SATURDAY. ZONAL
FLOW EARLY ON SATURDAY BECOMES WEST-SOUTHWESTERLY BY SATURDAY
AFTERNOON...THEN SOUTHWESTERLY SATURDAY NIGHT. THE SYNOPTIC SCALE
ENERGY IS BENIGN FRIDAY INTO MID DAY SATURDAY...THEN WEAK UPWARD
VERTICAL VELOCITY IS PROGGED BY AFTERNOON THROUGH SATURDAY NIGHT.
THE LOW LEVEL PRESSURE AND WIND FIELDS ELUDE TO NORMAL DIURNAL WIND
PATTERNS FOR FRIDAY. BY FRIDAY NIGHT...MODELS SHOW A SURGE OF
EASTERLY WINDS MOVING INTO THE EASTERN PLAINS. THEY GET INTO THE
EASTERN TWO-THIRDS OF THE PLAINS BY SATURDAY MORNING. ON SATURDAY
.MODELS SHOW THE EASTERLY UPSLOPE GETTING ACROSS ALL THE PLAINS
INTO THE LOWER FOOTHILLS. BY SATURDAY NIGHT...NORMAL WINDS
PATTERNS SHOULD RETURN. FOR MOISTURE...THERE IS QUITE A BIT ON
FRIDAY. IT`S FAIRLY DEEP OVER THE MOUNTAINS ON THE GFS IN THE
MORNING...BUT IN THE AFTERNOON ON THE NAM. BY AFTERNOON...THERE IS
QUITE A BIT OF MID AND UPPER LEVEL MOISTURE OVER THE PLAINS. THERE
IS NOT MUCH MOISTURE OVER THE MOUNTAINS FRIDAY NIGHT AND SATURDAY
MORNING...BUT MODELS DO SHOW STRATUS OVER ALL THE PLAINS. THE NAM
INCREASES MOISTURE FROM THE WEST AND DEEPENS IT SATURDAY AFTERNOON
AND NIGHT. THE GFS DOES NOT BRING THIS IN TO MOUNTAINS UNTIL LATER
SATURDAY NIGHT. BOTH KEEP THE LOW LEVEL MOISTURE OVER THE PLAINS
THE REST OF THE SATURDAY AND SATURDAY NIGHT. THE QPF FIELDS HAVE A
TAD OF MEASURABLE PRECIPITATION OVER THE MOUNTAINS FRIDAY MORNING
.THEN MORE BY AFTERNOON AS WELL AS SOME OVER THE NORTHERN BORDER
OF THE CWA. THIS CONTINUES FRIDAY NIGHT. ON SATURDAY...THERE IS A
TAD OF MEASURABLE PRECIPITATION OVER ALL THE PLAINS...BUT NOTHING
FOR THE MOUNTAINS. BY SATURDAY NIGHT...THERE IS A BIT OVER THE
MOUNTAINS...WITH THE PLAINS DRY. SO FOR POPS...NOT TO EXCITING.
MOISTURE IS PROBLEMATIC BETWEEN MODELS. THE SYNOPTIC SCALE ENERGY
IS WEAK AND DOESN`T KICK IN UNTIL SATURDAY AFTERNOON....AND THE
MOUNTAINS HAVE NEUTRAL OR WARM-AIR ADVECTION MUCH OF THE TIME. ALSO
IN THE MOUNTAINS...OROGRAPHICS ARE NOT GOOD. SO WILL GO WITH
20-30%S IN THE MOUNTAINS ON FRIDAY AND FRIDAY NIGHT...AND THEN AGAIN
SATURDAY AFTERNOON AND NIGHT. WILL GO WITH 20% POPS OVER THE
NORTHERN PLAINS FRIDAY NIGHT INTO SATURDAY...THEN OVER ALL THE
PLAINS SATURDAY AFTERNOON AND NIGHT. FOR TEMPERATURES...FRIDAY`S
HIGHS ARE A TAD WARMER THAN TODAY`S...EXCEPT OVER THE NORTHEAST
CORNER WITH THE NEW AIRMASS IN PLACE. THIS COOLER AIR WILL LIKELY
MAKE IT ACROSS ALL THE PLAINS ON FRIDAY. ALSO...REAL TEMPERATURE
DATA OVER THE LAST FEW DAYS HAS BEEN INFLUENCED BY THE SNOW FIELD IN
PLACE. SATURDAY`S HIGHS ARE 3-4 C COOLER FOR THE PLAINS AND
FOOTHILLS...BUT A BIT WARMER OVER THE MOUNTAINS. FOR THE LATER
DAYS...SUNDAY THROUGH WEDNESDAY...MODELS HAVE A WEAK UPPER TROUGH
MOVE ACROSS ON SUNDAY...THEN UPPER RIDGING ON MONDAY INTO TUESDAY.
BY LATER TUESDAY NIGHT AND WEDNESDAY...ANOTHER UPPER TROUGH MOVES
IN. BOTH THE ECMWF AND GFS SHOW SOME VERSION OF THIS...BUT ITS
PRETTY CONVOLUTED. MOISTURE IS NOT GREAT SUNDAY THROUGH TUESDAY.
ON WEDNESDAY IT IS A BIT BETTER...ESPECIALLY ON THE GFS...BUT NOT
GREAT AND NOT CONSISTENT. I DOUBT TEMPERATURES WILL WARM TO
SEASONAL NUMBERS ANY OF THE FOUR DAYS.
AVIATION...VFR CONDITIONS EXPECTED THROUGH TONIGHT. SOME
UNCERTAINTY ON WIND DIRECTION AGAIN THIS AFTERNOON. IT NOW LOOKS
LIKE WE SHOULD HAVE NORTH TO NORTHWEST WINDS THIS AFTERNOON...
POSSIBLY AS MUCH AS 10 KNOTS AT KDEN...THEN BACK TO S/W DRAINAGE
WINDS THIS EVENING. THERE IS A CHANCE THAT WINDS WILL JUST BECOME
LIGHT AND VARIABLE.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...D-L
LONG TERM....RJK
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1114 AM MST THU FEB 9 2012
.UPDATE...
HAVE UPDATED POPS AND CLOUD COVER OVER THE NWRN PLATEAU/MTN
COUNTRY. THIS AS A CHANNELED VORT PATTERN AND EXISTING MOISTURE
COMBINE TO PRODUCE LIGHT SNOWFALL IN THAT AREA.
&&
.SHORT TERM /REST OF TODAY THROUGH FRIDAY NIGHT/...
KGJT RAOB INDICATED THAT MOISTURE HAD ARRIVED AS ANTICIPATED
DOUBLING OVER THE PAST 24 HOURS REACHING ALMOST .40 OF AN INCH.
ALSO AS EXPECTED...THE PRECIPITATION EXPANDED OVER WESTERN COLORADO
DURING THE EVENING AND EARLY MORNING HOURS AS WATER VAPOR SHOWED A
DISTINCT SHORTWAVE DROPPING INTO EASTERN UTAH. SNOTELS OVER MOST
OF THE REGION SEEMED TO INDICATED THINKING THE PAST FEW DAYS OF A
LIGHT SNOWFALL EVENT IN THE 2 TO 5 INCH RANGE MOST PLACES...WITH A
FEW LOCALLY HIGHER AMOUNTS. ONE EXCEPTION AS NOTED IN EARLIER
DISCUSSION WAS IN ZONE 18 ALONG HIGHWAY 55O FROM THE GORGE UP TO
RED MOUNTAIN PASS WHERE 2 INCH SNOW RATES WERE REPORTED. KGJX VWP
SHOWED AN INCREASINGLY LIGHT NORTHERLY FLOW EARLY THIS MORNING AND
WITH THE MAIN VORT PASSING JUST TO THE EAST SNOWFALL PRODUCTION
WAS VERY EFFICIENT. THIS WAVE WILL BE PASSING AND THE OVERALL
ASCENT WILL BE DECREASING...BUT THE MOIST FAVORABLE FLOW UP THE
GORGE SHOULD KEEP ACCUMULATING SNOW POSSIBLE THROUGH AT LEAST MID
MORNING. IN THE WAKE OF THE WAVE MOVING INTO THE 4 CORNERS
REGION...THE LOSS OF HIGHER CLOUD COVER AND NEW SNOW COVER HAS
ALLOWED DENSE FOG TO FORM OVER THE WESTERN GRAND VALLEY AS HAVE
ISSUED AN ADVISORY TO COVER THIS THROUGH MID MORNING.
WATER VAPOR WOULD INDICATED THE BULK OF THE MOISTURE IS BEING SWEPT
EASTWARD THIS MORNING AND QG FIELDS SUGGEST SUBSIDENCE OR WEAKENING
ASCENT IS TAKING OVER AS WELL. THIS SHOULD LEAVE OROGRAPHICS AS THE
MAIN MODE FOR PRECIP PRODUCTION IN THE NORTHERLY FLOW. HOWEVER
SATELLITE PICS HINT THAT THE NEXT WAVE DROPPING INTO NORTHWEST
WYOMING IS STILL CAPABLE OF PRODUCING SOME LIFT...AND THE RUC QG
FIELD ARE TRENDING STRONGER WITH THE ASCENT OVER NORTHERN COLORADO
THROUGH NOON. THEREFORE HAVE KEPT POPS FAIRLY HIGH OVER THE NORTHERN
AND CENTRAL MOUNTAINS THIS MORNING...AS WELL AS PORTIONS OF THE SAN
JUAN MOUNTAINS MENTIONED ABOVE. THE NORTHWEST PLATEAU AND UPPER I-70
VALLEYS SHOULD ALSO SEE ENOUGH LIFT TO GET LIGHT SNOW THROUGH MID
MORNING. THIS AFTERNOON THE WYOMING WAVE LOOKS TO DRAG SOME MUCH
COOLER AIR OVER CENTRAL COLORADO SO DECIDED TO KEEP SCATTERED
SHOWERS MENTIONED IN THE MOUNTAINS DUE TO TH ADDED INSTABILITY.
ADDITIONAL SNOW ACCUMS SHOULD BE QUITE LIGHT WITH DRIER AIR WORKING
IN BEHIND THE WAVE AS WELL.
THE RADAR SHOULD QUIET DOWN AFTER SUNSET WITH RELAXING LAPSE RATES
AND A TEMPORARY LULL IN SHORT WAVE ENERGY MOVING THROUGH THE
NORTHWEST FLOW. ON FRIDAY THE AMPLIFIED RIDGE IN THE WEST WILL BEGIN
TO BE FLATTENED BY ENERGY EJECTING FROM AN EASTERN PAC LOW. SOME OF
THIS ENERGY WILL DROP OVER THE RIDGE AND SPILL INTO NORTHERN
COLORADO THROUGH THE DAY. THEREFORE WILL GO AHEAD AND INCREASE POPS
SLIGHTLY FRIDAY INTO FRIDAY NIGHT...WITH NEW SNOWFALL AMOUNTS
EXPECTED TO REMAIN BELOW MOUNTAIN ADVISORY CRITERIA.
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
THE MEDIUM RANGE PERIOD FEATURES A SIGNIFICANT SPLIT IN FLOW OVER
THE CONTINENT WITH A RIDGE OF HIGH PRESSURE OVER THE WESTERN
CANADIAN PROVINCES AND A TROUGH OVER THE SOUTHWESTERN U.S. MODELS
WERE SIMILAR IN CARRYING THE TROUGH ONTO THE CALIFORNIA COAST ON
SATURDAY PUMPING UP A SHORTWAVE RIDGE OVER THE FORECAST AREA. THOUGH
SOME MID-LEVEL MOISTURE ENTRAINED IN THE SOUTHWEST FLOW...CHANCES FOR
PRECIPITATION APPEARED LIMITED.
HOWEVER...PRECIPITATION CHANCES INCREASE GOING INTO THE LATTER PART
OF THE WEEKEND AS THE LOW PRESSURE TROUGH SWINGS ACROSS THE GREAT
BASIN SATURDAY NIGHT...THEN ACROSS EASTERN UTAH AND WESTERN
COLORADO ON SUNDAY. ECMWF SOLUTION CARRIES ENERGY A BIT FARTHER
SOUTH THAN THE GFS40...HOWEVER BOTH INDICATED SIGNIFICANT SNOWFALL
IS POSSIBLE WITH THIS SYSTEM AS SNOW LINGERS OVER THE MOUNTAINS
THROUGH SUNDAY NIGHT.
SNOWFALL CHANCES DECREASE MONDAY AS A SHORTWAVE RIDGE DEVELOPS AHEAD
OF THE NEXT LOW PRESSURE SYSTEM MOVING ONSHORE. MODELS DIVERGE WITH
THIS NEXT STORM WITH THE ECMWF AGAIN FARTHER SOUTH THAN THE GFS40.
REGARDLESS OF THEIR DIFFERENCES...BOTH MODELS INDICATED THAT
UNSETTLED CONDITIONS WILL REDEVELOP TUESDAY AND WILL PERSIST INTO
WEDNESDAY.
TEMPERATURES WILL BE WARMER THAN NORMAL SATURDAY AS WARM SOUTHWEST
FLOW DEVELOPS AHEAD OF THE SYSTEM WHICH WILL IMPACT THE REGION THIS
WEEKEND. HOWEVER...A COOLING TREND BEGINS SUNDAY AS YET ANOTHER
SYSTEM MOVES THROUGH THE AREA AS DESCRIBED ABOVE.
&&
.AVIATION /FOR 12Z TAF ISSUANCE/...
AREAS OF FOG WILL CONTINUE TO RESTRICT VSBY TO MVFR CONDITIONS
ALONG THE LOWER I-70 CORRIDOR UNTIL AROUND NOON...WHILE LIGHT SNOW
CONTINUES AT THE HIGHER ELEVATION TAF SITES. FOR THIS AFTERNOON A
MOIST NORTHWESTERLY FLOW WILL BRING INSTABILITY SHOWERS TO THE
NORTHWEST PLATEAU AND MTN COUNTRY WITH MVFR CONDITIONS EXPECTED THROUGH
THIS AFTERNOON. VFR CONDITIONS ARE ANTICIPATED TO RETURN TONIGHT...
ALTHOUGH PATCHY LOCALIZED FOG MAY REDEVELOP AFTER MIDNIGHT.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
SHORT TERM...MC
LONG TERM....NL
AVIATION.....MC
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1056 AM MST THU FEB 9 2012
.UPDATE...SHORTWAVE CURRENTLY PASSING ACROSS AREA...STILL QUITE A
BIT OF CLOUDS ACROSS MUCH OF CFWA. WEB CAMS AND RADAR LOOPS
SHOWING PERSISTANT LIGHT SNOW OVER THE MOUNTAINS...MAINLY ALONG
THE CONTINENTAL DIVIDE. DESPITE SUBSIDENCE THIS AFTERNOON BEHIND
EXITING SHORTWAVE...BOTH NAM AND RUC STILL KEEP QUITE A BIT OF
CLOUD OVER THE MOUNTAINS...ALONG WITH LIGHT QPF/SNOW AMOUNTS ALONG
THE DIVIDE. BASED ON THE CURRENT TRENDS...WILL NEED TO KEEP A
CHANCE OF SNOW OVER THE HIGHER PEAKS THROUGH MUCH OF THE
AFTERNOON. OTHERWISE...TREND TOWARD DECREASING CLOUDS STILL
LOOKING ON TRACK FOR NOW. REST OF FORECAST TRENDS ALSO ON TRACK.
&&
.AVIATION...CURRENT TAF TRENDS SEEM ON TRACK...DID KEEP THE BROKEN
MID LEVEL A BIT LONGER. LATEST NAM AND GFS GUIDANCE SHOWING A
BROKEN 6000-7000 AGL DECK THROUGH 21Z. NOT SURE IF THIS WILL PAN
OUT BASED ON AREA OBSERVATIONS. A BIT OF STRATUS TOWARDS CASPER
WITH SOME LIGHT SNOW...DON`T THINK IT WILL PUSH INTO COLORADO ANY
TIME SOON.
&&
.PREV DISCUSSION... /ISSUED 400 AM MST THU FEB 9 2012/
SHORT TERM...WEAK SHORTWAVE MOVING ACROSS COLORADO THIS MORNING.
MOISTURE WILL BE DIMINISHING FROM THE NORTHWEST THOUGH A FEW SNOW
SHOWERS MAY HANG ON INTO THE AFTERNOON IN THE HIGH MOUNTAINS. NOT A
LOT OF TEMPERATURE ADVECTION WITH THIS TROUGH...A WARMER START TO
THE DAY AND A BIT MORE MIXING AS A RESULT...SO WILL TRY AGAIN FOR A
WARMER DAY OVER THE PLAINS. WE WILL LIKELY SEE THE SAME TEMPERATURE
PATTERN HOWEVER...JUST NOT AS EXTREME. STILL NEED TO DROP FORECAST
HIGHS ON THE PLAINS...UNDERCUTTING MOS GUIDANCE IN MOST AREAS DUE TO
THE SNOW COVER. MOSTLY CLEAR SKIES THIS EVENING THEN SOME INCREASE
IN CLOUD COVER POSSIBLE AGAIN TOWARD MORNING. COOLED LOWS IN THE
MOUNTAIN VALLEYS...BUT NOT AS MUCH AS GUIDANCE SINCE THERE IS STILL
SOME MOISTURE AND PROBABLY SOME CLOUD COVER AGAIN TOWARD MORNING.
LONG TERM...NORTHWESTERLY FLOW ALOFT IS PROGGED FRIDAY INTO FRIDAY
NIGHT. THEN AN UPPER RIDGE MOVES ACROSS THROUGH SATURDAY. ZONAL
FLOW EARLY ON SATURDAY BECOMES WEST-SOUTHWESTERLY BY SATURDAY
AFTERNOON...THEN SOUTHWESTERLY SATURDAY NIGHT. THE SYNOPTIC SCALE
ENERGY IS BENIGN FRIDAY INTO MID DAY SATURDAY...THEN WEAK UPWARD
VERTICAL VELOCITY IS PROGGED BY AFTERNOON THROUGH SATURDAY NIGHT.
THE LOW LEVEL PRESSURE AND WIND FIELDS ELUDE TO NORMAL DIURNAL WIND
PATTERNS FOR FRIDAY. BY FRIDAY NIGHT...MODELS SHOW A SURGE OF
EASTERLY WINDS MOVING INTO THE EASTERN PLAINS. THEY GET INTO THE
EASTERN TWO-THIRDS OF THE PLAINS BY SATURDAY MORNING. ON SATURDAY
..MODELS SHOW THE EASTERLY UPSLOPE GETTING ACROSS ALL THE PLAINS
INTO THE LOWER FOOTHILLS. BY SATURDAY NIGHT...NORMAL WINDS
PATTERNS SHOULD RETURN. FOR MOISTURE...THERE IS QUITE A BIT ON
FRIDAY. IT`S FAIRLY DEEP OVER THE MOUNTAINS ON THE GFS IN THE
MORNING...BUT IN THE AFTERNOON ON THE NAM. BY AFTERNOON...THERE IS
QUITE A BIT OF MID AND UPPER LEVEL MOISTURE OVER THE PLAINS. THERE
IS NOT MUCH MOISTURE OVER THE MOUNTAINS FRIDAY NIGHT AND SATURDAY
MORNING...BUT MODELS DO SHOW STRATUS OVER ALL THE PLAINS. THE NAM
INCREASES MOISTURE FROM THE WEST AND DEEPENS IT SATURDAY AFTERNOON
AND NIGHT. THE GFS DOES NOT BRING THIS IN TO MOUNTAINS UNTIL LATER
SATURDAY NIGHT. BOTH KEEP THE LOW LEVEL MOISTURE OVER THE PLAINS
THE REST OF THE SATURDAY AND SATURDAY NIGHT. THE QPF FIELDS HAVE A
TAD OF MEASURABLE PRECIPITATION OVER THE MOUNTAINS FRIDAY MORNING
..THEN MORE BY AFTERNOON AS WELL AS SOME OVER THE NORTHERN BORDER
OF THE CWA. THIS CONTINUES FRIDAY NIGHT. ON SATURDAY...THERE IS A
TAD OF MEASURABLE PRECIPITATION OVER ALL THE PLAINS...BUT NOTHING
FOR THE MOUNTAINS. BY SATURDAY NIGHT...THERE IS A BIT OVER THE
MOUNTAINS...WITH THE PLAINS DRY. SO FOR POPS...NOT TO EXCITING.
MOISTURE IS PROBLEMATIC BETWEEN MODELS. THE SYNOPTIC SCALE ENERGY
IS WEAK AND DOESN`T KICK IN UNTIL SATURDAY AFTERNOON....AND THE
MOUNTAINS HAVE NEUTRAL OR WARM-AIR ADVECTION MUCH OF THE TIME. ALSO
IN THE MOUNTAINS...OROGRAPHICS ARE NOT GOOD. SO WILL GO WITH
20-30%S IN THE MOUNTAINS ON FRIDAY AND FRIDAY NIGHT...AND THEN AGAIN
SATURDAY AFTERNOON AND NIGHT. WILL GO WITH 20% POPS OVER THE
NORTHERN PLAINS FRIDAY NIGHT INTO SATURDAY...THEN OVER ALL THE
PLAINS SATURDAY AFTERNOON AND NIGHT. FOR TEMPERATURES...FRIDAY`S
HIGHS ARE A TAD WARMER THAN TODAY`S...EXCEPT OVER THE NORTHEAST
CORNER WITH THE NEW AIRMASS IN PLACE. THIS COOLER AIR WILL LIKELY
MAKE IT ACROSS ALL THE PLAINS ON FRIDAY. ALSO...REAL TEMPERATURE
DATA OVER THE LAST FEW DAYS HAS BEEN INFLUENCED BY THE SNOW FIELD IN
PLACE. SATURDAY`S HIGHS ARE 3-4 C COOLER FOR THE PLAINS AND
FOOTHILLS...BUT A BIT WARMER OVER THE MOUNTAINS. FOR THE LATER
DAYS...SUNDAY THROUGH WEDNESDAY...MODELS HAVE A WEAK UPPER TROUGH
MOVE ACROSS ON SUNDAY...THEN UPPER RIDGING ON MONDAY INTO TUESDAY.
BY LATER TUESDAY NIGHT AND WEDNESDAY...ANOTHER UPPER TROUGH MOVES
IN. BOTH THE ECMWF AND GFS SHOW SOME VERSION OF THIS...BUT ITS
PRETTY CONVOLUTED. MOISTURE IS NOT GREAT SUNDAY THROUGH TUESDAY.
ON WEDNESDAY IT IS A BIT BETTER...ESPECIALLY ON THE GFS...BUT NOT
GREAT AND NOT CONSISTENT. I DOUBT TEMPERATURES WILL WARM TO
SEASONAL NUMBERS ANY OF THE FOUR DAYS.
AVIATION...VFR CONDITIONS EXPECTED THROUGH TONIGHT. SOME
UNCERTAINTY ON WIND DIRECTION AGAIN THIS AFTERNOON. IT NOW LOOKS
LIKE WE SHOULD HAVE NORTH TO NORTHWEST WINDS THIS AFTERNOON...
POSSIBLY AS MUCH AS 10 KNOTS AT KDEN...THEN BACK TO S/W DRAINAGE
WINDS THIS EVENING. THERE IS A CHANCE THAT WINDS WILL JUST BECOME
LIGHT AND VARIABLE.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...D-L
LONG TERM....RJK
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
936 AM MST THU FEB 9 2012
.SHORT TERM /REST OF TODAY THROUGH FRIDAY NIGHT/...
KGJT RAOB INDICATED THAT MOISTURE HAD ARRIVED AS ANTICIPATED
DOUBLING OVER THE PAST 24 HOURS REACHING ALMOST .40 OF AN INCH.
ALSO AS EXPECTED...THE PRECIPITATION EXPANDED OVER WESTERN COLORADO
DURING THE EVENING AND EARLY MORNING HOURS AS WATER VAPOR SHOWED A
DISTINCT SHORTWAVE DROPPING INTO EASTERN UTAH. SNOTELS OVER MOST
OF THE REGION SEEMED TO INDICATED THINKING THE PAST FEW DAYS OF A
LIGHT SNOWFALL EVENT IN THE 2 TO 5 INCH RANGE MOST PLACES...WITH A
FEW LOCALLY HIGHER AMOUNTS. ONE EXCEPTION AS NOTED IN EARLIER
DISCUSSION WAS IN ZONE 18 ALONG HIGHWAY 55O FROM THE GORGE UP TO
RED MOUNTAIN PASS WHERE 2 INCH SNOW RATES WERE REPORTED. KGJX VWP
SHOWED AN INCREASINGLY LIGHT NORTHERLY FLOW EARLY THIS MORNING AND
WITH THE MAIN VORT PASSING JUST TO THE EAST SNOWFALL PRODUCTION
WAS VERY EFFICIENT. THIS WAVE WILL BE PASSING AND THE OVERALL
ASCENT WILL BE DECREASING...BUT THE MOIST FAVORABLE FLOW UP THE
GORGE SHOULD KEEP ACCUMULATING SNOW POSSIBLE THROUGH AT LEAST MID
MORNING. IN THE WAKE OF THE WAVE MOVING INTO THE 4 CORNERS
REGION...THE LOSS OF HIGHER CLOUD COVER AND NEW SNOW COVER HAS
ALLOWED DENSE FOG TO FORM OVER THE WESTERN GRAND VALLEY AS HAVE
ISSUED AN ADVISORY TO COVER THIS THROUGH MID MORNING.
WATER VAPOR WOULD INDICATED THE BULK OF THE MOISTURE IS BEING SWEPT
EASTWARD THIS MORNING AND QG FIELDS SUGGEST SUBSIDENCE OR WEAKENING
ASCENT IS TAKING OVER AS WELL. THIS SHOULD LEAVE OROGRAPHICS AS THE
MAIN MODE FOR PRECIP PRODUCTION IN THE NORTHERLY FLOW. HOWEVER
SATELLITE PICS HINT THAT THE NEXT WAVE DROPPING INTO NORTHWEST
WYOMING IS STILL CAPABLE OF PRODUCING SOME LIFT...AND THE RUC QG
FIELD ARE TRENDING STRONGER WITH THE ASCENT OVER NORTHERN COLORADO
THROUGH NOON. THEREFORE HAVE KEPT POPS FAIRLY HIGH OVER THE NORTHERN
AND CENTRAL MOUNTAINS THIS MORNING...AS WELL AS PORTIONS OF THE SAN
JUAN MOUNTAINS MENTIONED ABOVE. THE NORTHWEST PLATEAU AND UPPER I-70
VALLEYS SHOULD ALSO SEE ENOUGH LIFT TO GET LIGHT SNOW THROUGH MID
MORNING. THIS AFTERNOON THE WYOMING WAVE LOOKS TO DRAG SOME MUCH
COOLER AIR OVER CENTRAL COLORADO SO DECIDED TO KEEP SCATTERED
SHOWERS MENTIONED IN THE MOUNTAINS DUE TO TH ADDED INSTABILITY.
ADDITIONAL SNOW ACCUMS SHOULD BE QUITE LIGHT WITH DRIER AIR WORKING
IN BEHIND THE WAVE AS WELL.
THE RADAR SHOULD QUIET DOWN AFTER SUNSET WITH RELAXING LAPSE RATES
AND A TEMPORARY LULL IN SHORT WAVE ENERGY MOVING THROUGH THE
NORTHWEST FLOW. ON FRIDAY THE AMPLIFIED RIDGE IN THE WEST WILL BEGIN
TO BE FLATTENED BY ENERGY EJECTING FROM AN EASTERN PAC LOW. SOME OF
THIS ENERGY WILL DROP OVER THE RIDGE AND SPILL INTO NORTHERN
COLORADO THROUGH THE DAY. THEREFORE WILL GO AHEAD AND INCREASE POPS
SLIGHTLY FRIDAY INTO FRIDAY NIGHT...WITH NEW SNOWFALL AMOUNTS
EXPECTED TO REMAIN BELOW MOUNTAIN ADVISORY CRITERIA.
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
THE MEDIUM RANGE PERIOD FEATURES A SIGNIFICANT SPLIT IN FLOW OVER
THE CONTINENT WITH A RIDGE OF HIGH PRESSURE OVER THE WESTERN
CANADIAN PROVINCES AND A TROUGH OVER THE SOUTHWESTERN U.S. MODELS
WERE SIMILAR IN CARRYING THE TROUGH ONTO THE CALIFORNIA COAST ON
SATURDAY PUMPING UP A SHORTWAVE RIDGE OVER THE FORECAST AREA. THOUGH
SOME MID-LEVEL MOISTURE ENTRAINED IN THE SOUTHWEST FLOW...CHANCES FOR
PRECIPITATION APPEARED LIMITED.
HOWEVER...PRECIPITATION CHANCES INCREASE GOING INTO THE LATTER PART
OF THE WEEKEND AS THE LOW PRESSURE TROUGH SWINGS ACROSS THE GREAT
BASIN SATURDAY NIGHT...THEN ACROSS EASTERN UTAH AND WESTERN
COLORADO ON SUNDAY. ECMWF SOLUTION CARRIES ENERGY A BIT FARTHER
SOUTH THAN THE GFS40...HOWEVER BOTH INDICATED SIGNIFICANT SNOWFALL
IS POSSIBLE WITH THIS SYSTEM AS SNOW LINGERS OVER THE MOUNTAINS
THROUGH SUNDAY NIGHT.
SNOWFALL CHANCES DECREASE MONDAY AS A SHORTWAVE RIDGE DEVELOPS AHEAD
OF THE NEXT LOW PRESSURE SYSTEM MOVING ONSHORE. MODELS DIVERGE WITH
THIS NEXT STORM WITH THE ECMWF AGAIN FARTHER SOUTH THAN THE GFS40.
REGARDLESS OF THEIR DIFFERENCES...BOTH MODELS INDICATED THAT
UNSETTLED CONDITIONS WILL REDEVELOP TUESDAY AND WILL PERSIST INTO
WEDNESDAY.
TEMPERATURES WILL BE WARMER THAN NORMAL SATURDAY AS WARM SOUTHWEST
FLOW DEVELOPS AHEAD OF THE SYSTEM WHICH WILL IMPACT THE REGION THIS
WEEKEND. HOWEVER...A COOLING TREND BEGINS SUNDAY AS YET ANOTHER
SYSTEM MOVES THROUGH THE AREA AS DESCRIBED ABOVE.
&&
.AVIATION /FOR 18Z TAF ISSUANCE/...
AREAS OF FOG WILL CONTINUE TO RESTRICT VSBY TO MVFR CONDITIONS
ALONG THE LOWER I-70 CORRIDOR UNTIL AROUND NOON...WHILE LIGHT SNOW
CONTINUES AT THE HIGHER ELEVATION TAF SITES. FOR THIS AFTERNOON A
MOIST NORTHWESTERLY FLOW WILL BRING INSTABILITY SHOWERS TO THE
NORTHWEST PLATEAU AND MTN COUNTRY WITH MVFR CONDITIONS EXPECTED THROUGH
THIS AFTERNOON. VFR CONDITIONS ARE ANTICIPATED TO RETURN TONIGHT...
ALTHOUGH PATCHY LOCALIZED FOG MAY REDEVELOP AFTER MIDNIGHT.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
SHORT TERM...MC
LONG TERM....NL
AVIATION.....MC
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
904 AM MST THU FEB 9 2012
.UPDATE...
SNOW HAS MOSTLY ENDED OVER THE GORGE AREA OF THE NORTHWESTERN SAN
JUAN MOUNTAINS...SO ALLOWED THE SNOW ADVISORY IN THAT AREA TO
EXPIRE AT 0900. IN THE WESTERN GRAND VALLEY VISIBILITIES CONTINUE
TO IMPROVE SO ALLOWED THE DENSE FOG ADVISORY TO EXPIRE AT 0900 IN
THAT AREA AS WELL.
&&
.SHORT TERM /REST OF TODAY THROUGH FRIDAY NIGHT/...
KGJT RAOB INDICATED THAT MOISTURE HAD ARRIVED AS ANTICIPATED
DOUBLING OVER THE PAST 24 HOURS REACHING ALMOST .40 OF AN INCH.
ALSO AS EXPECTED...THE PRECIPITATION EXPANDED OVER WESTERN COLORADO
DURING THE EVENING AND EARLY MORNING HOURS AS WATER VAPOR SHOWED A
DISTINCT SHORTWAVE DROPPING INTO EASTERN UTAH. SNOTELS OVER MOST
OF THE REGION SEEMED TO INDICATED THINKING THE PAST FEW DAYS OF A
LIGHT SNOWFALL EVENT IN THE 2 TO 5 INCH RANGE MOST PLACES...WITH A
FEW LOCALLY HIGHER AMOUNTS. ONE EXCEPTION AS NOTED IN EARLIER
DISCUSSION WAS IN ZONE 18 ALONG HIGHWAY 55O FROM THE GORGE UP TO
RED MOUNTAIN PASS WHERE 2 INCH SNOW RATES WERE REPORTED. KGJX VWP
SHOWED AN INCREASINGLY LIGHT NORTHERLY FLOW EARLY THIS MORNING AND
WITH THE MAIN VORT PASSING JUST TO THE EAST SNOWFALL PRODUCTION
WAS VERY EFFICIENT. THIS WAVE WILL BE PASSING AND THE OVERALL
ASCENT WILL BE DECREASING...BUT THE MOIST FAVORABLE FLOW UP THE
GORGE SHOULD KEEP ACCUMULATING SNOW POSSIBLE THROUGH AT LEAST MID
MORNING. IN THE WAKE OF THE WAVE MOVING INTO THE 4 CORNERS
REGION...THE LOSS OF HIGHER CLOUD COVER AND NEW SNOW COVER HAS
ALLOWED DENSE FOG TO FORM OVER THE WESTERN GRAND VALLEY AS HAVE
ISSUED AN ADVISORY TO COVER THIS THROUGH MID MORNING.
WATER VAPOR WOULD INDICATED THE BULK OF THE MOISTURE IS BEING SWEPT
EASTWARD THIS MORNING AND QG FIELDS SUGGEST SUBSIDENCE OR WEAKENING
ASCENT IS TAKING OVER AS WELL. THIS SHOULD LEAVE OROGRAPHICS AS THE
MAIN MODE FOR PRECIP PRODUCTION IN THE NORTHERLY FLOW. HOWEVER
SATELLITE PICS HINT THAT THE NEXT WAVE DROPPING INTO NORTHWEST
WYOMING IS STILL CAPABLE OF PRODUCING SOME LIFT...AND THE RUC QG
FIELD ARE TRENDING STRONGER WITH THE ASCENT OVER NORTHERN COLORADO
THROUGH NOON. THEREFORE HAVE KEPT POPS FAIRLY HIGH OVER THE NORTHERN
AND CENTRAL MOUNTAINS THIS MORNING...AS WELL AS PORTIONS OF THE SAN
JUAN MOUNTAINS MENTIONED ABOVE. THE NORTHWEST PLATEAU AND UPPER I-70
VALLEYS SHOULD ALSO SEE ENOUGH LIFT TO GET LIGHT SNOW THROUGH MID
MORNING. THIS AFTERNOON THE WYOMING WAVE LOOKS TO DRAG SOME MUCH
COOLER AIR OVER CENTRAL COLORADO SO DECIDED TO KEEP SCATTERED
SHOWERS MENTIONED IN THE MOUNTAINS DUE TO TH ADDED INSTABILITY.
ADDITIONAL SNOW ACCUMS SHOULD BE QUITE LIGHT WITH DRIER AIR WORKING
IN BEHIND THE WAVE AS WELL.
THE RADAR SHOULD QUIET DOWN AFTER SUNSET WITH RELAXING LAPSE RATES
AND A TEMPORARY LULL IN SHORT WAVE ENERGY MOVING THROUGH THE
NORTHWEST FLOW. ON FRIDAY THE AMPLIFIED RIDGE IN THE WEST WILL BEGIN
TO BE FLATTENED BY ENERGY EJECTING FROM AN EASTERN PAC LOW. SOME OF
THIS ENERGY WILL DROP OVER THE RIDGE AND SPILL INTO NORTHERN
COLORADO THROUGH THE DAY. THEREFORE WILL GO AHEAD AND INCREASE POPS
SLIGHTLY FRIDAY INTO FRIDAY NIGHT...WITH NEW SNOWFALL AMOUNTS
EXPECTED TO REMAIN BELOW MOUNTAIN ADVISORY CRITERIA.
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
THE MEDIUM RANGE PERIOD FEATURES A SIGNIFICANT SPLIT IN FLOW OVER
THE CONTINENT WITH A RIDGE OF HIGH PRESSURE OVER THE WESTERN
CANADIAN PROVINCES AND A TROUGH OVER THE SOUTHWESTERN U.S. MODELS
WERE SIMILAR IN CARRYING THE TROUGH ONTO THE CALIFORNIA COAST ON
SATURDAY PUMPING UP A SHORTWAVE RIDGE OVER THE FORECAST AREA. THOUGH
SOME MID-LEVEL MOISTURE ENTRAINED IN THE SOUTHWEST FLOW...CHANCES FOR
PRECIPITATION APPEARED LIMITED.
HOWEVER...PRECIPITATION CHANCES INCREASE GOING INTO THE LATTER PART
OF THE WEEKEND AS THE LOW PRESSURE TROUGH SWINGS ACROSS THE GREAT
BASIN SATURDAY NIGHT...THEN ACROSS EASTERN UTAH AND WESTERN
COLORADO ON SUNDAY. ECMWF SOLUTION CARRIES ENERGY A BIT FARTHER
SOUTH THAN THE GFS40...HOWEVER BOTH INDICATED SIGNIFICANT SNOWFALL
IS POSSIBLE WITH THIS SYSTEM AS SNOW LINGERS OVER THE MOUNTAINS
THROUGH SUNDAY NIGHT.
SNOWFALL CHANCES DECREASE MONDAY AS A SHORTWAVE RIDGE DEVELOPS AHEAD
OF THE NEXT LOW PRESSURE SYSTEM MOVING ONSHORE. MODELS DIVERGE WITH
THIS NEXT STORM WITH THE ECMWF AGAIN FARTHER SOUTH THAN THE GFS40.
REGARDLESS OF THEIR DIFFERENCES...BOTH MODELS INDICATED THAT
UNSETTLED CONDITIONS WILL REDEVELOP TUESDAY AND WILL PERSIST INTO
WEDNESDAY.
TEMPERATURES WILL BE WARMER THAN NORMAL SATURDAY AS WARM SOUTHWEST
FLOW DEVELOPS AHEAD OF THE SYSTEM WHICH WILL IMPACT THE REGION THIS
WEEKEND. HOWEVER...A COOLING TREND BEGINS SUNDAY AS YET ANOTHER
SYSTEM MOVES THROUGH THE AREA AS DESCRIBED ABOVE.
&&
.AVIATION /FOR 12Z TAF ISSUANCE/...
EXPECT WIDESPREAD MVFR CIGS AND VSBY ALONG A KRKS-30W KGJT-35NW KCEZ-
30SW KPSO AS A FAST MOVING SHORTWAVE TROUGH CONTINUES TO IMPACT MUCH
OF COLORADO EARLY THIS MORNING. RESIDUAL LOW-LEVEL MOISTURE AND
CLEARING SKIES ON THE BACK SIDE OF THIS SYSTEM WILL RESULT IN AREAS
OF FOG ACROSS THE CENTRAL COLORADO VALLEYS INCLUDING KGJT...KRIL...
KMTJ AND KASE. PERIODS OF IFR/LIFR CONDITIONS ARE LIKELY AT TIMES.
MEANWHILE...LINGERING SNOW IN THE COLORADO MOUNTAINS WILL BRING
WIDESPREAD MOUNTAIN OBSCURATIONS THROUGH MIDDAY. CONDITIONS IMPROVE
FROM WEST TO EAST DURING THE AFTERNOON. MOUNTAINS SNOW WILL BECOME
SHOWERY AND SCATTERED IN COVERAGE. MEANWHILE...EXPECT VFR
CONDITIONS ACROSS ALL OF EASTERN UTAH AND THE SOUTHWEST CORNER OF
COLORADO TODAY.
SHOWERS DIMINISH SHORTLY AFTER SUNSET AND VFR CONDITIONS WILL BECOME
THE RULE OVERNIGHT.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
SHORT TERM...MC
LONG TERM....NL
AVIATION.....NL
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
814 AM MST THU FEB 9 2012
.UPDATE...
BASED ON LOCAL OBSERVATIONS AND WEB CAMS DECIDED TO EXTEND THE
DENSE FOG ADVISORY UNTIL 0900. THE FOG SEEMED ESPECIALLY DENSE
ALONG THE I-70 CORRIDOR WHICH IS A BIG IMPACT.
&&
.SHORT TERM /REST OF TODAY THROUGH FRIDAY NIGHT/...
KGJT RAOB INDICATED THAT MOISTURE HAD ARRIVED AS ANTICIPATED
DOUBLING OVER THE PAST 24 HOURS REACHING ALMOST .40 OF AN INCH.
ALSO AS EXPECTED...THE PRECIPITATION EXPANDED OVER WESTERN COLORADO
DURING THE EVENING AND EARLY MORNING HOURS AS WATER VAPOR SHOWED A
DISTINCT SHORTWAVE DROPPING INTO EASTERN UTAH. SNOTELS OVER MOST
OF THE REGION SEEMED TO INDICATED THINKING THE PAST FEW DAYS OF A
LIGHT SNOWFALL EVENT IN THE 2 TO 5 INCH RANGE MOST PLACES...WITH A
FEW LOCALLY HIGHER AMOUNTS. ONE EXCEPTION AS NOTED IN EARLIER
DISCUSSION WAS IN ZONE 18 ALONG HIGHWAY 55O FROM THE GORGE UP TO
RED MOUNTAIN PASS WHERE 2 INCH SNOW RATES WERE REPORTED. KGJX VWP
SHOWED AN INCREASINGLY LIGHT NORTHERLY FLOW EARLY THIS MORNING AND
WITH THE MAIN VORT PASSING JUST TO THE EAST SNOWFALL PRODUCTION
WAS VERY EFFICIENT. THIS WAVE WILL BE PASSING AND THE OVERALL
ASCENT WILL BE DECREASING...BUT THE MOIST FAVORABLE FLOW UP THE
GORGE SHOULD KEEP ACCUMULATING SNOW POSSIBLE THROUGH AT LEAST MID
MORNING. IN THE WAKE OF THE WAVE MOVING INTO THE 4 CORNERS
REGION...THE LOSS OF HIGHER CLOUD COVER AND NEW SNOW COVER HAS
ALLOWED DENSE FOG TO FORM OVER THE WESTERN GRAND VALLEY AS HAVE
ISSUED AN ADVISORY TO COVER THIS THROUGH MID MORNING.
WATER VAPOR WOULD INDICATED THE BULK OF THE MOISTURE IS BEING SWEPT
EASTWARD THIS MORNING AND QG FIELDS SUGGEST SUBSIDENCE OR WEAKENING
ASCENT IS TAKING OVER AS WELL. THIS SHOULD LEAVE OROGRAPHICS AS THE
MAIN MODE FOR PRECIP PRODUCTION IN THE NORTHERLY FLOW. HOWEVER
SATELLITE PICS HINT THAT THE NEXT WAVE DROPPING INTO NORTHWEST
WYOMING IS STILL CAPABLE OF PRODUCING SOME LIFT...AND THE RUC QG
FIELD ARE TRENDING STRONGER WITH THE ASCENT OVER NORTHERN COLORADO
THROUGH NOON. THEREFORE HAVE KEPT POPS FAIRLY HIGH OVER THE NORTHERN
AND CENTRAL MOUNTAINS THIS MORNING...AS WELL AS PORTIONS OF THE SAN
JUAN MOUNTAINS MENTIONED ABOVE. THE NORTHWEST PLATEAU AND UPPER I-70
VALLEYS SHOULD ALSO SEE ENOUGH LIFT TO GET LIGHT SNOW THROUGH MID
MORNING. THIS AFTERNOON THE WYOMING WAVE LOOKS TO DRAG SOME MUCH
COOLER AIR OVER CENTRAL COLORADO SO DECIDED TO KEEP SCATTERED
SHOWERS MENTIONED IN THE MOUNTAINS DUE TO TH ADDED INSTABILITY.
ADDITIONAL SNOW ACCUMS SHOULD BE QUITE LIGHT WITH DRIER AIR WORKING
IN BEHIND THE WAVE AS WELL.
THE RADAR SHOULD QUIET DOWN AFTER SUNSET WITH RELAXING LAPSE RATES
AND A TEMPORARY LULL IN SHORT WAVE ENERGY MOVING THROUGH THE
NORTHWEST FLOW. ON FRIDAY THE AMPLIFIED RIDGE IN THE WEST WILL BEGIN
TO BE FLATTENED BY ENERGY EJECTING FROM AN EASTERN PAC LOW. SOME OF
THIS ENERGY WILL DROP OVER THE RIDGE AND SPILL INTO NORTHERN
COLORADO THROUGH THE DAY. THEREFORE WILL GO AHEAD AND INCREASE POPS
SLIGHTLY FRIDAY INTO FRIDAY NIGHT...WITH NEW SNOWFALL AMOUNTS
EXPECTED TO REMAIN BELOW MOUNTAIN ADVISORY CRITERIA.
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
THE MEDIUM RANGE PERIOD FEATURES A SIGNIFICANT SPLIT IN FLOW OVER
THE CONTINENT WITH A RIDGE OF HIGH PRESSURE OVER THE WESTERN
CANADIAN PROVINCES AND A TROUGH OVER THE SOUTHWESTERN U.S. MODELS
WERE SIMILAR IN CARRYING THE TROUGH ONTO THE CALIFORNIA COAST ON
SATURDAY PUMPING UP A SHORTWAVE RIDGE OVER THE FORECAST AREA. THOUGH
SOME MID-LEVEL MOISTURE ENTRAINED IN THE SOUTHWEST FLOW...CHANCES FOR
PRECIPITATION APPEARED LIMITED.
HOWEVER...PRECIPITATION CHANCES INCREASE GOING INTO THE LATTER PART
OF THE WEEKEND AS THE LOW PRESSURE TROUGH SWINGS ACROSS THE GREAT
BASIN SATURDAY NIGHT...THEN ACROSS EASTERN UTAH AND WESTERN
COLORADO ON SUNDAY. ECMWF SOLUTION CARRIES ENERGY A BIT FARTHER
SOUTH THAN THE GFS40...HOWEVER BOTH INDICATED SIGNIFICANT SNOWFALL
IS POSSIBLE WITH THIS SYSTEM AS SNOW LINGERS OVER THE MOUNTAINS
THROUGH SUNDAY NIGHT.
SNOWFALL CHANCES DECREASE MONDAY AS A SHORTWAVE RIDGE DEVELOPS AHEAD
OF THE NEXT LOW PRESSURE SYSTEM MOVING ONSHORE. MODELS DIVERGE WITH
THIS NEXT STORM WITH THE ECMWF AGAIN FARTHER SOUTH THAN THE GFS40.
REGARDLESS OF THEIR DIFFERENCES...BOTH MODELS INDICATED THAT
UNSETTLED CONDITIONS WILL REDEVELOP TUESDAY AND WILL PERSIST INTO
WEDNESDAY.
TEMPERATURES WILL BE WARMER THAN NORMAL SATURDAY AS WARM SOUTHWEST
FLOW DEVELOPS AHEAD OF THE SYSTEM WHICH WILL IMPACT THE REGION THIS
WEEKEND. HOWEVER...A COOLING TREND BEGINS SUNDAY AS YET ANOTHER
SYSTEM MOVES THROUGH THE AREA AS DESCRIBED ABOVE.
&&
.AVIATION /FOR 12Z TAF ISSUANCE/...
EXPECT WIDESPREAD MVFR CIGS AND VSBY ALONG A KRKS-30W KGJT-35NW KCEZ-
30SW KPSO AS A FAST MOVING SHORTWAVE TROUGH CONTINUES TO IMPACT MUCH
OF COLORADO EARLY THIS MORNING. RESIDUAL LOW-LEVEL MOISTURE AND
CLEARING SKIES ON THE BACK SIDE OF THIS SYSTEM WILL RESULT IN AREAS
OF FOG ACROSS THE CENTRAL COLORADO VALLEYS INCLUDING KGJT...KRIL...
KMTJ AND KASE. PERIODS OF IFR/LIFR CONDITIONS ARE LIKELY AT TIMES.
MEANWHILE...LINGERING SNOW IN THE COLORADO MOUNTAINS WILL BRING
WIDESPREAD MOUNTAIN OBSCURATIONS THROUGH MIDDAY. CONDITIONS IMPROVE
FROM WEST TO EAST DURING THE AFTERNOON. MOUNTAINS SNOW WILL BECOME
SHOWERY AND SCATTERED IN COVERAGE. MEANWHILE...EXPECT VFR
CONDITIONS ACROSS ALL OF EASTERN UTAH AND THE SOUTHWEST CORNER OF
COLORADO TODAY.
SHOWERS DIMINISH SHORTLY AFTER SUNSET AND VFR CONDITIONS WILL BECOME
THE RULE OVERNIGHT.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...DENSE FOG ADVISORY UNTIL 9 AM MST THIS MORNING FOR ZONE 006.
WINTER WEATHER ADVISORY UNTIL 9 AM MST THIS MORNING FOR ZONE 018.
UT...NONE.
&&
$$
SHORT TERM...MC
LONG TERM....NL
AVIATION.....NL
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
436 AM MST THU FEB 9 2012
.SHORT TERM /TODAY THROUGH FRIDAY NIGHT/...
KGJT RAOB INDICATED THAT MOISTURE HAD ARRIVED AS ANTICIPATED
DOUBLING OVER THE PAST 24 HOURS REACHING ALMOST .40 OF AN INCH.
ALSO AS EXPECTED...THE PRECIPITATION EXPANDED OVER WESTERN COLORADO
DURING THE EVENING AND EARLY MORNING HOURS AS WATER VAPOR SHOWED A
DISTINCT SHORTWAVE DROPPING INTO EASTERN UTAH. SNOTELS OVER MOST
OF THE REGION SEEMED TO INDICATED THINKING THE PAST FEW DAYS OF A
LIGHT SNOWFALL EVENT IN THE 2 TO 5 INCH RANGE MOST PLACES...WITH A
FEW LOCALLY HIGHER AMOUNTS. ONE EXCEPTION AS NOTED IN EARLIER
DISCUSSION WAS IN ZONE 18 ALONG HIGHWAY 55O FROM THE GORGE UP TO
RED MOUNTAIN PASS WHERE 2 INCH SNOW RATES WERE REPORTED. KGJX VWP
SHOWED AN INCREASINGLY LIGHT NORTHERLY FLOW EARLY THIS MORNING AND
WITH THE MAIN VORT PASSING JUST TO THE EAST SNOWFALL PRODUCTION
WAS VERY EFFICIENT. THIS WAVE WILL BE PASSING AND THE OVERALL
ASCENT WILL BE DECREASING...BUT THE MOIST FAVORABLE FLOW UP THE
GORGE SHOULD KEEP ACCUMULATING SNOW POSSIBLE THROUGH AT LEAST MID
MORNING. IN THE WAKE OF THE WAVE MOVING INTO THE 4 CORNERS
REGION...THE LOSS OF HIGHER CLOUD COVER AND NEW SNOW COVER HAS
ALLOWED DENSE FOG TO FORM OVER THE WESTERN GRAND VALLEY AS HAVE
ISSUED AN ADVISORY TO COVER THIS THROUGH MID MORNING.
WATER VAPOR WOULD INDICATED THE BULK OF THE MOISTURE IS BEING SWEPT
EASTWARD THIS MORNING AND QG FIELDS SUGGEST SUBSIDENCE OR WEAKENING
ASCENT IS TAKING OVER AS WELL. THIS SHOULD LEAVE OROGRAPHICS AS THE
MAIN MODE FOR PRECIP PRODUCTION IN THE NORTHERLY FLOW. HOWEVER
SATELLITE PICS HINT THAT THE NEXT WAVE DROPPING INTO NORTHWEST
WYOMING IS STILL CAPABLE OF PRODUCING SOME LIFT...AND THE RUC QG
FIELD ARE TRENDING STRONGER WITH THE ASCENT OVER NORTHERN COLORADO
THROUGH NOON. THEREFORE HAVE KEPT POPS FAIRLY HIGH OVER THE NORTHERN
AND CENTRAL MOUNTAINS THIS MORNING...AS WELL AS PORTIONS OF THE SAN
JUAN MOUNTAINS MENTIONED ABOVE. THE NORTHWEST PLATEAU AND UPPER I-70
VALLEYS SHOULD ALSO SEE ENOUGH LIFT TO GET LIGHT SNOW THROUGH MID
MORNING. THIS AFTERNOON THE WYOMING WAVE LOOKS TO DRAG SOME MUCH
COOLER AIR OVER CENTRAL COLORADO SO DECIDED TO KEEP SCATTERED
SHOWERS MENTIONED IN THE MOUNTAINS DUE TO TH ADDED INSTABILITY.
ADDITIONAL SNOW ACCUMS SHOULD BE QUITE LIGHT WITH DRIER AIR WORKING
IN BEHIND THE WAVE AS WELL.
THE RADAR SHOULD QUIET DOWN AFTER SUNSET WITH RELAXING LAPSE RATES
AND A TEMPORARY LULL IN SHORT WAVE ENERGY MOVING THROUGH THE
NORTHWEST FLOW. ON FRIDAY THE AMPLIFIED RIDGE IN THE WEST WILL BEGIN
TO BE FLATTENED BY ENERGY EJECTING FROM AN EASTERN PAC LOW. SOME OF
THIS ENERGY WILL DROP OVER THE RIDGE AND SPILL INTO NORTHERN
COLORADO THROUGH THE DAY. THEREFORE WILL GO AHEAD AND INCREASE POPS
SLIGHTLY FRIDAY INTO FRIDAY NIGHT...WITH NEW SNOWFALL AMOUNTS
EXPECTED TO REMAIN BELOW MOUNTAIN ADVISORY CRITERIA.
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
THE MEDIUM RANGE PERIOD FEATURES A SIGNIFICANT SPLIT IN FLOW OVER
THE CONTINENT WITH A RIDGE OF HIGH PRESSURE OVER THE WESTERN
CANADIAN PROVINCES AND A TROUGH OVER THE SOUTHWESTERN U.S. MODELS
WERE SIMILAR IN CARRYING THE TROUGH ONTO THE CALIFORNIA COAST ON
SATURDAY PUMPING UP A SHORTWAVE RIDGE OVER THE FORECAST AREA. THOUGH
SOME MID-LEVEL MOISTURE ENTRAINED IN THE SOUTHWEST FLOW...CHANCES FOR
PRECIPITATION APPEARED LIMITED.
HOWEVER...PRECIPITATION CHANCES INCREASE GOING INTO THE LATTER PART
OF THE WEEKEND AS THE LOW PRESSURE TROUGH SWINGS ACROSS THE GREAT
BASIN SATURDAY NIGHT...THEN ACROSS EASTERN UTAH AND WESTERN
COLORADO ON SUNDAY. ECMWF SOLUTION CARRIES ENERGY A BIT FARTHER
SOUTH THAN THE GFS40...HOWEVER BOTH INDICATED SIGNIFICANT SNOWFALL
IS POSSIBLE WITH THIS SYSTEM AS SNOW LINGERS OVER THE MOUNTAINS
THROUGH SUNDAY NIGHT.
SNOWFALL CHANCES DECREASE MONDAY AS A SHORTWAVE RIDGE DEVELOPS AHEAD
OF THE NEXT LOW PRESSURE SYSTEM MOVING ONSHORE. MODELS DIVERGE WITH
THIS NEXT STORM WITH THE ECMWF AGAIN FARTHER SOUTH THAN THE GFS40.
REGARDLESS OF THEIR DIFFERENCES...BOTH MODELS INDICATED THAT
UNSETTLED CONDITIONS WILL REDEVELOP TUESDAY AND WILL PERSIST INTO
WEDNESDAY.
TEMPERATURES WILL BE WARMER THAN NORMAL SATURDAY AS WARM SOUTHWEST
FLOW DEVELOPS AHEAD OF THE SYSTEM WHICH WILL IMPACT THE REGION THIS
WEEKEND. HOWEVER...A COOLING TREND BEGINS SUNDAY AS YET ANOTHER
SYSTEM MOVES THROUGH THE AREA AS DESCRIBED ABOVE.
&&
.AVIATION /FOR 12Z TAF ISSUANCE/...
EXPECT WIDESPREAD MVFR CIGS AND VSBY ALONG A KRKS-30W KGJT-35NW KCEZ-
30SW KPSO AS A FAST MOVING SHORTWAVE TROUGH CONTINUES TO IMPACT MUCH
OF COLORADO EARLY THIS MORNING. RESIDUAL LOW-LEVEL MOISTURE AND
CLEARING SKIES ON THE BACK SIDE OF THIS SYSTEM WILL RESULT IN AREAS
OF FOG ACROSS THE CENTRAL COLORADO VALLEYS INCLUDING KGJT...KRIL...
KMTJ AND KASE. PERIODS OF IFR/LIFR CONDITIONS ARE LIKELY AT TIMES.
MEANWHILE...LINGERING SNOW IN THE COLORADO MOUNTAINS WILL BRING
WIDESPREAD MOUNTAIN OBSCURATIONS THROUGH MIDDAY. CONDITIONS IMPROVE
FROM WEST TO EAST DURING THE AFTERNOON. MOUNTAINS SNOW WILL BECOME
SHOWERY AND SCATTERED IN COVERAGE. MEANWHILE...EXPECT VFR
CONDITIONS ACROSS ALL OF EASTERN UTAH AND THE SOUTHWEST CORNER OF
COLORADO TODAY.
SHOWERS DIMINISH SHORTLY AFTER SUNSET AND VFR CONDITIONS WILL BECOME
THE RULE OVERNIGHT.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...DENSE FOG ADVISORY UNTIL 8 AM MST THIS MORNING FOR ZONE 006.
WINTER WEATHER ADVISORY UNTIL 9 AM MST THIS MORNING FOR ZONE 018.
UT...NONE.
&&
$$
SHORT TERM...15
LONG TERM....NL
AVIATION.....NL
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
204 AM MST THU FEB 9 2012
.UPDATE...
UPDATED TO ADD A WINTER WEATHER ADVISORY FOR ZONE 18 FOR THE
REMAINDER OF TONIGHT INTO THE MIDDLE OF THE MORNING. SNOTELS WITHIN
THE HIGHWAY 550 CORRIDOR FROM OURAY SOUTH TO RED MOUNTAIN PASS
INDICATED AS MUCH AS 7 INCHES OF NEW SNOW HAS ACCUMULATED OVER THE
PAST FEW HOURS. AVALANCHE FORECASTER FROM THE SILVERTON OFFICE
REPORTED SNOWFALL RATES OF UP TO 2 INCHES PER HOUR. BASED ON
SATELLITE AND RUC ANALYSES...LIFT WAS JUST PEAKING OVER THIS AREA
AS THE SHORTWAVE TROUGH AXIS POISED TO MOVE EAST OF THE SAN JUANS
SHORTLY. THOUGH LARGE SCALE LIFT WILL DIMINISH...NORTHERLY FLOW ON
THE BACK SIDE OF THE TROUGH WILL CONTINUE TO GENERATE SUFFICIENT
OROGRAPHIC LIFT TO KEEP SNOW GOING ALONG THE 550 CORRIDOR SOUTH OF
RIDGWAY INTO THE MIDDLE OF THE MORNING. THIS SHOULD BRING 2 TO 5
ADDITIONAL INCHES AND THEREFORE HAVE ISSUED A WINTER WEATHER
ADVISORY FOR THIS AREA.
&&
.PREV DISCUSSION /ISSUED 846 PM MST WED FEB 8 2012/...
SHORT TERM /REST OF TONIGHT THROUGH FRIDAY/...
A FAST MOVING SHORTWAVE TROUGH WILL CONTINUE MOVING THROUGH THE
FORECAST AREA TONIGHT WITH PEAK QG FORCING AROUND MIDNIGHT OVER
WRN CO. MOISTURE WILL HAVE ALREADY INCREASED IN THE SWRLY FLOW
ALOFT TODAY WITH SPECIFIC HUMIDITY AROUND 3 G/KG. SYSTEM SEEMS TO
LACK A GREAT DEAL OF THERMAL SUPPORT WITH NO ORGANIZED SFC COLD
FRONT AND JET ENERGY PRETTY WELL REMOVED AS WELL. HOWEVER UPSTREAM
RIDGE IS AMPLIFYING AND THIS MEANS THE SHRT WV SHOULD BE IN THE
DEEPENING MODE. GENERALLY RAISED POPS AND INCREASED SNOW AMOUNTS
FOR OUR MTNS...BUT AMOUNTS STILL REMAIN BELOW ADVISORY CRITERIA.
BOTH THE GFS AND NAM SHOW THE MOST FAVORED LOCATION TO BE OVER THE
FLATTOPS WHERE 3-5 INCHES WILL BE COMMON WITH LOCALLY HIGHER
AMOUNTS.
THIS TROF QUICKLY DROPS TO THE SOUTHEAST THURSDAY AND THE FLOW
ALOFT VEERS TO THE NORTHWEST IN COLD ADVECTION PATTERN. EXPECT A
FEW SNOW SHOWERS TO LINGER OVER THE NORTH FACING SLOPES DURING THE
MORNING WITH ADDITIONAL LIGHT SNOW ACCUMULATIONS. BY AFTERNOON
SHWRS QUICKLY TAPER OFF AS LOW LEVEL LAPSE RATES STABILIZE. HEIGHTS
WILL BEGIN TO RISE THURSDAY NIGHT AS A RIDGE BUILDS OVER THE
DESERT SOUTHWEST. NO PRECIP IS EXPECTED BUT SOME HIGH CLOUDS MAY
DRIFT ACROSS THE NORTH.
AN INCREASINGLY MOIST NWRLY FLOW IS EXPECTED FRIDAY AND SOME
EMBEDDED VERY WEAK WAVES LIKELY TO ACT ON THIS MOISTURE. THE NAM IS
MUCH MORE ROBUST WITH DEVELOPING PRECIP...BUT IT APPEARS LIMITED
TO THE NRN MTNS. MEANWHILE THE GFS ESSENTIALLY KEEPS OUR CWA DRY.
WILL SORT OF COMPROMISE AND RAISE POPS TO THE ISOLATED CATEGORY
ACROSS THE NORTH TO COVER ANY SHWRS THAT MAY DEVELOP.
LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
LONGWAVE RIDGE ALONG THE WEST COAST IS EXPECTED TO DE-AMPLIFY THIS
WEEKEND AND ALLOW PACIFIC ENERGY TO DROP INTO THE GREAT BASIN. THIS
SHOULD RESULT IN A SERIES OF DISTURBANCES AFFECTING THE FORECAST
AREA THROUGH THE MIDDLE OF NEXT WEEK. FORECAST CONFIDENCE IS GOOD
THROUGH MONDAY THEN LOWERS TUESDAY-WEDNESDAY AS MODEL DIFFERENCES
GROW.
NW FLOW WILL KEEP A CHANCE OF LIGHT SNOW IN THE NORTHERN CO MTNS FRI
NIGHT. FLOW ALOFT SHIFTS TO THE SOUTHWEST FOR SATURDAY AS A PACIFIC
SHORTWAVE TROUGH DIGS SOUTHWARD INTO NV. THIS TROUGH APPEARS TO
SPLIT WITH THE STRONGEST PIECE OF ENERGY DROPPING TO AZ SAT NIGHT
AND THEN MOVING EAST ACROSS NM ON SUNDAY. DECENT MOISTURE LOOKS TO
ACCOMPANY THIS SYSTEM. CLOUDS WILL BE ON THE INCREASE SATURDAY WITH
THE CHANCE OF PRECIPITATION INCREASING SATURDAY NIGHT IN WARM
ADVECTION. THE BEST CHANCE SHOULD BE ON SUNDAY AS THE TROUGH BODILY
MOVES ACROSS THE FORECAST AREA.
A TRANSIENT SHORTWAVE RIDGE SLIDES ACROSS ERN UT/WRN CO ON MONDAY AS
THE NEXT AND STRONGER LOOKING PACIFIC TROUGH DROPS INTO THE GREAT
BASIN. THIS TROUGH DEEPENS AS IT APPROACHES WITH THE 12Z GFS
BRINGING A CLOSED 500 MB LOW ACROSS THE 4 CORNERS ABOUT NOON ON
TUESDAY. 12Z CANADIAN MODEL HAS SIMILAR TIMING BUT TRACKS THE UPPER
LOW CENTER ALONG THE BOOKCLIFFS...WHILE THE 12Z ECMWF IS NOW SLOWER
THAN ITS PREVIOUS RUN AND DOESN/T BRING THE LOW/TROUGH ACROSS
SOUTHWEST CO UNTIL WED MORNING. WILL BUMP POPS UP FROM THE CONSENSUS
MODEL MON NIGHT THROUGH TUESDAY NIGHT BUT STILL KEEP IN IT IN THE
CHANCE CATEGORY DUE TO DIFFERENCES IN THE TIMING...BUT THIS STORM
COULD HAVE THE MAKINGS FOR SIGNIFICANT SNOW IN THE CENTRAL AND
SOUTHERN MTNS ESPECIALLY.
TEMPERATURES WILL VARY WITH THE PASSING STORMS...WARMING ON SATURDAY
AND MONDAY AHEAD OF THE TROUGHS AND THEN COOLING BEHIND THEM.
AVIATION /FOR 06Z TAF ISSUANCE/...
FLIGHT CONDITIONS WILL CONTINUE DETERIORATING OVERNIGHT AT ALL TAF SITES
AS CIGS LOWER WITH THE APPROACH OF THE NEXT FAST-MOVING SYSTEM.
MVFR CIGS/VIS IN AREAS OF -SN WILL CONTINUE OVER KGJT...KRIL...
KASE...AND KEGE WITH PERIODS OF IFR CIGS IN SN AND BR EXPECTED.
MOUNTAINS AND THE HIGHER PASSES WILL BE OBSCURED MOST OF THE NIGHT.
MVFR CONDITIONS IN -SN WITH OCCASIONALLY IFR CIGS WILL ALSO
CONTINUE AT KCAG/KHDN/KSBS. CONDITIONS WILL BE IMPROVING FROM THE
NORTHWEST ON THURSDAY.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...WINTER WEATHER ADVISORY UNTIL 9 AM MST THIS MORNING FOR ZONE 018.
UT...NONE.
&&
$$
UPDATE.......NL
SHORT TERM...MC/CJC
LONG TERM....JAD
AVIATION.....JAD/CJC
AREA FORECAST DISCUSSION...UPDATED FOR AVIATION SECTION
NWS TALLAHASSEE FL
530 AM EST Thu Feb 9 2012
.SYNOPSIS...
07Z water vapor and H4 RUC analysis shows an upper level pattern
along the northern Gulf coast dominated by southern stream flow.
Main belt of westerlies lies to our north helping to keep our
weather quiet...at least for today. Similar to the past several
days, WV imagery suggest we will continue to see periods of high
level cirrus streaming overhead to filter the sunshine. Looking
upstream, we see shortwave energy diving southeast across the
inter-mountain west toward the Southern Plains. It will be this
energy that will bring our next potential for showers Friday night
as it ejects quickly eastward and over our region.
At the surface,
1030mb high pressure is centered along the middle MS Valley this
morning. Our position well to its southeast results in a decent
gradient across the area, and is providing steady northerly breezes.
In response to the wind, our temperatures are a bit warmer than
previously expected. In fact, some spots that had dropped into the
middle 40s earlier, have rebounded several degrees in response to
the low level mixing.
&&
.SHORT TERM (TODAY THROUGH SATURDAY)...
Today,
Dry and seasonably pleasant weather. Surface ridge will build south
through the day allowing the gradient to weaken. Our skies will
feature filtered sunshine as upper level moisture continues to
stream overhead in the form of cirrus. Less efficient mixing should
generally keep high temperatures a few degrees cooler than what was
experience Wednesday. Current grids show mid-afternoon temps
reaching the lower 60s north and middle to upper 60s south. Far
southeast portions of the Big Bend/Suwannee River Valley will make a
run at the lower 70s.
Tonight,
With the surface ridge center in closer proximity, will see a better
chance for low temps to fall into the middle to upper 30s late. Best
chances to reach these numbers will be west of the Suwannee River
Valley/I-75 corridor. Developing light easterly flow associated with
an organizing surface trough along the FL East Coast is expected to
transport a slight increase in Atlantic moisture into these far
eastern zones, and keep low temps in the lower/middle 40s. Current
numbers suggest only a minimal frost threat.
Friday,
Daylight hours of Friday will feature generally dry conditions with
increasing clouds. GFS has come around to support the earlier
solution of the ECMWF/CMC of a more well-defined mid-level shortwave
approaching from the west. As it appears now, deep layer synoptic
support/QG-forcing associated with this energy, along with the best
upper level jet configuration will not arrive until Friday
evening/night, and will keep shower chances out of the forecast.
Despite the increasing clouds, at least some filtered sunshine and a
weak thermal ridge ahead of the approaching system should allow
temperatures to rebound into the mid/upper 60s for most areas, and
upper 60s/lower 70s for the FL Big Bend.
Friday Night,
Shortwave trough will pivot across the area accompanied by an
impressive 150+kt jetstreak. Global guidance members are in good
agreement showing the best deep layer lift combination of QG forcing
and jet dynamics will come together over the southern half of the
area...and especially offshore. Current grids will show slight
chance 20% PoPs north, and chance 30-50% Pops south of a line
roughly from Panama City to Tallahassee and Valdosta. Rainfall
amounts look to be on the light side, from maybe a few hundredths of
an inch north, to potentially a couple tenths over the coastal
waters and SE Big Bend zones. System will be quite progressive and
expect best lift and moisture to be quickly exiting to our east
toward sunrise.
Saturday,
Clearing skies and a much cooler/drier airmass will be arriving on
NW winds in the wake of Friday Night`s system. Been a while since we
saw 850mb temps down to zero overhead, but ECMWF/GFS both show the
850 zero line arriving by the end of the day. Although the daylight
hours of Saturday will still see temps reaching the low/mid 60s,
Saturday Night and Sunday Nights will feature some rather chilly
readings, and light freeze potential. More details in the long term
discussion below.
&&
.LONG TERM [Saturday night through next Thursday]...The large scale
longwave pattern commences rather amplified highlighted by trough
over wrn states, ridge over Nrn/Cntrl Rockies and Wrn Plains, a
trough amplifying over Ern states from Canada SWD to Nrn Gulf states
and a nearly zonal flow swd to local area. with srn stream quite
strong, a series of short waves will drop southward into the wrn
trough axis, then weaken as they head rapidly east or northeast
across the eastern U.S. At surface, in the wake of passing dry cold
front, strong 1032mb high builds SEWD from Plains providing a
noticeably colder and drier airmass. A light advective freeze is
likely inland early Sun and Mon mornings but on first morning this
will be contingent on wind speeds assocd with high which will still
be in the Lwr Ms Valley and doesnt favor ideal radiational cooling.
Winds however, will make it feel colder and expect bone dry RH will
favor fire wx hazards. By sunrise Monday, high will be almost
overhead with much lighter winds and better chance for nearly ideal
radiational cooling, and cant totally discount a hard freeze for
some areas.
Like our previous cold snaps this winter, it will be short lived as
by Sun aftn, the longwave pattern is expected to become more
progressive. Wrn trough amplifies over Desert SW while upstream
ridge moves rapidly ewd with axis over Wrn Gulf region by Sun night
or early Mon. This kicks ern trough into Wrn Atlc. By Mon aftn,
ridge axis has shifted rapidly ewd into extreme Wrn Atlc but
increasingly dampens in response to strong Nrn stream troughing. The
result is semi-zonal flow and the start of progressively moderating
temperatures overspreading NW Gulf region. At surface, ridge of high
pressure will nudge off SE states and into Wrn Atlc. The low level
flow veers allowing more moisture back into local region. Aloft,
weak ridging to zonal flow will persist Tuesday into Thursday. At
surface, next front aided by passing shortwave reaches Wrn Gulf by
end of period and with local area in warm sector, small chance of
rain per slower GFS. If EURO verifies, front could reach area on
Wed. With model discrepancies this far out, took a blend for my
timing and pop numbers.
Will go with wdly sct-lo sct pops Tues thru Wed, and wdly sct
on Thurs. Otherwise nil pops. With progressive pattern expect sharp
daily temp changes. Good chance of a a light freeze both sun/Mon
around sunrise with Mins both at least 10 degrees below climo. Max
temp Sun also around 10 degrees below normal. Then min/max temps
shoot up to around climo Mon/Mon night and around 10 degrees above
climo Tues thru Thur. (Avg inland climo is 41/66 degrees).
&&
.AVIATION [through 12z Fri]...
Unlimited visibility and VFR ceilings will continue through this
evening, except near any large forest fires that may flare up. At
this time, expect winds to remain elevated enough to keep boundary
layer mixed, and prevent significant restrictions due to smoke.
Small chance of Mvfr/borderline IFR CIGS and patchy fog near sunrise
Fri mainly GA terminals and at TLH. Will insert tempo groups here to
account for same.
&&
.MARINE...
A tight gradient early this morning will continue to support
cautionary level winds away from the immediate coast. The gradient
will weaken through the day allowing winds and seas to subside below
headline criteria for the afternoon. Generally light winds and seas
are then expected through the daylight hours of Friday. A cold front
will cross the forecast waters Friday night followed by cautionary
level northerly flow by Saturday afternoon. Winds and seas are then
expected to further increase to advisory levels Saturday night
through Sunday morning.
&&
.FIRE WEATHER...
A dry airmass will continue to overspread the region today. Minimum
humidity values are expected to reach the mid to upper 20s across
Georgia and the Florida Big Bend, with lower 30s expected elsewhere.
However, with ERC values as well as winds and dispersions below
critical levels, no red flag warnings are anticipated. Low level
moisture will begin to return on Friday with minimum humidity values
in the lower to mid 30s west of the Apalachicola River rising to the
40s east of the river. The airmass will begin to dry out again on
Saturday in the wake of a dry frontal passage and building high
north of the region. Minimum RH will hover around 35 percent on
Saturday before dropping precipitously into the teens on Sunday, the
next best chance of red flag conditions.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 67 38 70 45 64 / 0 0 10 30 10
Panama City 65 44 67 46 63 / 0 0 10 30 10
Dothan 61 39 66 41 59 / 0 0 10 20 10
Albany 62 37 67 40 61 / 0 0 10 20 10
Valdosta 65 41 70 44 63 / 0 0 10 30 10
Cross City 70 43 73 47 66 / 0 0 10 40 20
Apalachicola 64 41 66 45 63 / 0 0 10 40 10
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
AL...None.
GA...None.
FL...None.
GM...None.
&&
$$
SYNOPSIS/SHORT TERM/MARINE...MROCZKA
LONG TERM/AVIATION/FIRE WX...BLOCK
AREA FORECAST DISCUSSION...UPDATED FRO AVIATION SECTION
NWS TALLAHASSEE FL
250 AM EST Thu Feb 9 2012
.SYNOPSIS...
07Z water vapor and H4 RUC analysis shows an upper level pattern
along the northern Gulf coast dominated by southern stream flow.
Main belt of westerlies lies to our north helping to keep our
weather quiet...at least for today. Similar to the past several
days, WV imagery suggest we will continue to see periods of high
level cirrus streaming overhead to filter the sunshine. Looking
upstream, we see shortwave energy diving southeast across the
inter-mountain west toward the Southern Plains. It will be this
energy that will bring our next potential for showers Friday night
as it ejects quickly eastward and over our region.
At the surface,
1030mb high pressure is centered along the middle MS Valley this
morning. Our position well to its southeast results in a decent
gradient across the area, and is providing steady northerly breezes.
In response to the wind, our temperatures are a bit warmer than
previously expected. In fact, some spots that had dropped into the
middle 40s earlier, have rebounded several degrees in response to
the low level mixing.
&&
.SHORT TERM (TODAY THROUGH SATURDAY)...
Today,
Dry and seasonably pleasant weather. Surface ridge will build south
through the day allowing the gradient to weaken. Our skies will
feature filtered sunshine as upper level moisture continues to
stream overhead in the form of cirrus. Less efficient mixing should
generally keep high temperatures a few degrees cooler than what was
experience Wednesday. Current grids show mid-afternoon temps
reaching the lower 60s north and middle to upper 60s south. Far
southeast portions of the Big Bend/Suwannee River Valley will make a
run at the lower 70s.
Tonight,
With the surface ridge center in closer proximity, will see a better
chance for low temps to fall into the middle to upper 30s late. Best
chances to reach these numbers will be west of the Suwannee River
Valley/I-75 corridor. Developing light easterly flow associated with
an organizing surface trough along the FL East Coast is expected to
transport a slight increase in Atlantic moisture into these far
eastern zones, and keep low temps in the lower/middle 40s. Current
numbers suggest only a minimal frost threat.
Friday,
Daylight hours of Friday will feature generally dry conditions with
increasing clouds. GFS has come around to support the earlier
solution of the ECMWF/CMC of a more well-defined mid-level shortwave
approaching from the west. As it appears now, deep layer synoptic
support/QG-forcing associated with this energy, along with the best
upper level jet configuration will not arrive until Friday
evening/night, and will keep shower chances out of the forecast.
Despite the increasing clouds, at least some filtered sunshine and a
weak thermal ridge ahead of the approaching system should allow
temperatures to rebound into the mid/upper 60s for most areas, and
upper 60s/lower 70s for the FL Big Bend.
Friday Night,
Shortwave trough will pivot across the area accompanied by an
impressive 150+kt jetstreak. Global guidance members are in good
agreement showing the best deep layer lift combination of QG forcing
and jet dynamics will come together over the southern half of the
area...and especially offshore. Current grids will show slight
chance 20% PoPs north, and chance 30-50% Pops south of a line
roughly from Panama City to Tallahassee and Valdosta. Rainfall
amounts look to be on the light side, from maybe a few hundredths of
an inch north, to potentially a couple tenths over the coastal
waters and SE Big Bend zones. System will be quite progressive and
expect best lift and moisture to be quickly exiting to our east
toward sunrise.
Saturday,
Clearing skies and a much cooler/drier airmass will be arriving on
NW winds in the wake of Friday Night`s system. Been a while since we
saw 850mb temps down to zero overhead, but ECMWF/GFS both show the
850 zero line arriving by the end of the day. Although the daylight
hours of Saturday will still see temps reaching the low/mid 60s,
Saturday Night and Sunday Nights will feature some rather chilly
readings, and light freeze potential. More details in the long term
discussion below.
&&
.LONG TERM [Saturday night through next Thursday]...The large scale
longwave pattern commences rather amplified highlighted by trough
over wrn states, ridge over Nrn/Cntrl Rockies and Wrn Plains, a
trough amplifying over Ern states from Canada SWD to Nrn Gulf states
and a nearly zonal flow swd to local area. with srn stream quite
strong, a series of short waves will drop southward into the wrn
trough axis, then weaken as they head rapidly east or northeast
across the eastern U.S. At surface, in the wake of passing dry cold
front, strong 1032mb high builds SEWD from Plains providing a
noticeably colder and drier airmass. A light advective freeze is
likely inland early Sun and Mon mornings but on first morning this
will be contingent on wind speeds assocd with high which will still
be in the Lwr Ms Valley and doesnt favor ideal radiational cooling.
Winds however, will make it feel colder and expect bone dry RH will
favor fire wx hazards. By sunrise Monday, high will be almost
overhead with much lighter winds and better chance for nearly ideal
radiational cooling, and cant totally discount a hard freeze for
some areas.
Like our previous cold snaps this winter, it will be short lived as
by Sun aftn, the longwave pattern is expected to become more
progressive. Wrn trough amplifies over Desert SW while upstream
ridge moves rapidly ewd with axis over Wrn Gulf region by Sun night
or early Mon. This kicks ern trough into Wrn Atlc. By Mon aftn,
ridge axis has shifted rapidly ewd into extreme Wrn Atlc but
increasingly dampens in response to strong Nrn stream troughing. The
result is semi-zonal flow and the start of progressively moderating
temperatures overspreading NW Gulf region. At surface, ridge of high
pressure will nudge off SE states and into Wrn Atlc. The low level
flow veers allowing more moisture back into local region. Aloft,
weak ridging to zonal flow will persist Tuesday into Thursday. At
surface, next front aided by passing shortwave reaches Wrn Gulf by
end of period and with local area in warm sector, small chance of
rain per slower GFS. If EURO verifies, front could reach area on
Wed. With model discrepancies this far out, took a blend for my
timing and pop numbers.
Will go with wdly sct-lo sct pops Tues thru Wed, and wdly sct
on Thurs. Otherwise nil pops. With progressive pattern expect sharp
daily temp changes. Good chance of a a light freeze both sun/Mon
around sunrise with Mins both at least 10 degrees below climo. Max
temp Sun also around 10 degrees below normal. Then min/max temps
shoot up to around climo Mon/Mon night and around 10 degrees above
climo Tues thru Thur. (Avg inland climo is 41/66 degrees).
&&
.AVIATION [through 12z Fri]...
Unlimited visibility and VFR ceilings will continue through this
evening, except near any large forest fires that may flare up. At
this time, expect winds to remain elevated enough to keep boundary
layer mixed, and prevent significant restrictions due to smoke.
Small chance of Mvfr/borderline IFR CIGS and patchy fog near sunrise
Fri mainly GA terminals and at TLH. Will insert tempo groups here to
account for same.
&&
.MARINE...
A tight gradient early this morning will continue to support
cautionary level winds away from the immediate coast. The gradient
will weaken through the day allowing winds and seas to subside below
headline criteria for the afternoon. Generally light winds and seas
are then expected through the daylight hours of Friday. A cold front
will cross the forecast waters Friday night followed by cautionary
level northerly flow by Saturday afternoon. Winds and seas are then
expected to further increase to advisory levels Saturday night
through Sunday morning.
&&
.FIRE WEATHER...
A dry airmass will continue to overspread the region today. Minimum
humidity values are expected to reach the mid to upper 20s across
Georgia and the Florida Big Bend, with lower 30s expected elsewhere.
However, with ERC values as well as winds and dispersions below
critical levels, no red flag warnings are anticipated. Low level
moisture will begin to return on Friday with minimum humidity values
in the lower to mid 30s west of the Apalachicola River rising to the
40s east of the river. The airmass will begin to dry out again on
Saturday in the wake of a dry frontal passage and building high
north of the region. Minimum RH will hover around 35 percent on
Saturday before dropping precipitously into the teens on Sunday, the
next best chance of red flag conditions.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 67 38 70 45 64 / 0 0 10 30 10
Panama City 65 44 67 46 63 / 0 0 10 30 10
Dothan 61 39 66 41 59 / 0 0 10 20 10
Albany 62 37 67 40 61 / 0 0 10 20 10
Valdosta 65 41 70 44 63 / 0 0 10 30 10
Cross City 70 43 73 47 66 / 0 0 10 40 20
Apalachicola 64 41 66 45 63 / 0 0 10 40 10
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
AL...None.
GA...None.
FL...None.
GM...None.
&&
$$
SYNOPSIS/SHORT TERM/MARINE...MROCZKA
LONG TERM/AVIATION/FIRE WX...BLOCK
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1145 PM CST WED FEB 8 2012
.DISCUSSION...
ISSUED 851 PM CST WED FEB 8 2012
THE WESTERN AND NORTHERN EDGE OF THE CLOUDS IS BEGINNING TO MAKE
SOME PROGRESS INTO CENTRAL ILLINOIS. HOW SOON THE CLOUDS CLEAR OUT
AND IF THE CLEARING CONTINUES THROUGH MORNING WILL PLAY A MAJOR
ROLL IN LOW TEMPS FOR TONIGHT. SUBSIDENCE INVERSIONS UNDER HIGH
PRESSURE CAN TRAP LOW MOISTURE THAT FORM STRATUS CLOUDS WHICH FILL
IN AGAIN OR RETROGRADE BACK TO THE N-NE. THERE APPEARS TO BE
ENOUGH OF A CLEARING AREA ACROSS N MO/IOWA TO KEEP OUR CLEARING
TRENDS GOING. HAVE TRENDED SLOWER WITH THE CLEARING BASED ON
SATELLITE TRENDS AND THE LATEST HRRR MODEL OUTPUT.
THE SURFACE RIDGE APPEARS TO BE MAINLY SETTLING TO THE SOUTH
INSTEAD OF SLIDING EAST INTO ILLINOIS...SO THAT GIVES MORE
CONFIDENCE TO THE CLEARING SCENARIO. KEPT THE FORECAST LOWS SLIGHTLY
BELOW GUIDANCE...AND WE MAY NOT BE COLD ENOUGH. SURFACE DEWPOINTS
ARE QUITE DRY JUST TO OUR N AND W. WOULD NOT BE SURPRISED TO SEE
SOME MID TEENS REPORTED IN OUR NW COUNTIES IN THE MORNING. FOR
NOW...KEPT UPPER TEENS AND LOW 20S IN PLACE.
NO OTHER CHANGES WERE NEEDED TO THE CURRENT FORECAST/GRIDS.
UPDATED INFO IS ALREADY AVAILABLE.
SHIMON
&&
.AVIATION...
ISSUED 1145 PM CST WED FEB 8 2012...FOR THE 06Z TAFS
CLEARING OF MVFR CLOUDS IS FINALLY MAKING BETTER PROGRESS FROM THE
WEST AND NORTH. PIA AND BMI HAVE BECOME SCT...BUT PIA IS STILL
CLOSE TO A BKN DECK WITH A BAND OF CLOUDS JUST TO THE WEST OF THE
AIRPORT. EVEN WITH THAT...PIA SHOULD BECOME VFR SHORTLY AFTER 07Z
AFTER THOSE CLOUDS SLIDE SE. WILL CLEAR OUT THE REMAINING TAF
SITES BY 08Z-09Z...WITH SOME MVFR FOG POSSIBLE AS TEMPS FALL UNDER
CLEAR SKIES AND LIGHT WINDS. WE KEPT THE TEMPO GOING FM 11Z-14Z
TIME FRAME FOR ALL TERMINALS.
THE MAIN CHANGE TO THE TAFS WAS TO INCREASE VFR CLOUD COVER THUR
AFTERNOON AS WAA FLOWS INCREASE AHEAD OF THE NEXT SYSTEM. SW WINDS
WILL INCREASE TO 10-12KT ON THUR AS WELL.
CLOUDS WILL LIKELY CONTINUE THROUGH THE REMAINDER OF THE TAF
PERIOD...AND POSSIBLY DROP TO MVFR LEVELS AFTER SUNSET ON THURSDAY.
SHIMON
&&
.PREV DISCUSSION...
ISSUED 305 PM CST WED FEB 8 2012
SHORT TERM...TONIGHT THROUGH SATURDAY...
LARGE AREA OF HIGH PRESSURE OVER THE PLAINS WILL MOVE SOUTHEAST AND
DOMINATE THE WEATHER OVER IL TONIGHT THROUGH THURSDAY NIGHT.
EXTENSIVE CLOUD COVER OVER THE AREA WILL MOVE SLOWLY SOUTH WITH MOST
AREAS SEEING CLEAR SKIES BY SUNRISE. THE MAIN WEATHER FEATURE FOR
THE SHORT TERM WILL BE A STRONG COLD FRONT THAT WILL MOVE THROUGH
THE AREA ON FRIDAY. BY MIDDAY...THE FRONT SHOULD BE ABOUT MIDWAY
THROUGH THE FORECAST AREA...THEN INTO THE OHIO VALLEY BY 00Z SAT.
WITH THE CURRENT HIGH PRESSURE HAVING PUSHED MUCH OF THE QUALITY
MOISTURE FAR TO THE SOUTH...IT WILL TAKE SOME TIME FOR IT TO MAKE A
RETURN AND MAY NOT MAKE IT TO CENTRAL IL IN TIME TO INTERACT WITH
THE FRONT. SOME OF THE SHORT RANGE MODELS ARE PAINTING SOME QPF OVER
EASTERN IL WITH THE FRONT...SO WILL CONTINUE WITH SOME SLIGHT CHANCE
POPS THERE. AFTER THAT...THE LARGE CANADIAN AIRMASS IN THE WAKE OF
THE FRONT WILL SPREAD OVER THE CENTRAL/EASTERN CONUS BRINGING
TEMPERATURES BACK TO WINTER-TIME LEVELS STARTING FRIDAY NIGHT AND
LASTING INTO THE EXTENDED PERIOD. FOR NOW...IT APPEARS THAT FRIDAY
NIGHT INTO SATURDAY WILL BE THE COLDEST WITH LOWS 10-20 AND HIGHS IN
THE 20S.
LONG TERM...SUNDAY THROUGH WEDNESDAY...
THE GFS AND ECMWF ARE IN AGREEMENT THAT AN UPPER SHORTWAVE WILL COME
OUT OF THE SOUTHERN ROCKIES AND INTO THE PLAINS EARLY NEXT WEEK. BY
THEN...THE CANADIAN HIGH WILL BE OFF THE EAST COAST AND MOISTURE
FROM THE GULF WILL STREAM NORTHWARD THROUGH THE MS VALLEY. POPS WILL
BEGIN RISING ON MONDAY AS LIGHT SNOW...PERHAPS MIXED WITH LIGHT RAIN
AT THE START...MOVES INTO THE WESTERN HALF OF IL. HIGHEST CHANCE OF
PRECIPITATION WILL BE MONDAY NIGHT WITH THE PASSAGE OF THE UPPER
WAVE. ANY SURFACE REFLECTION OF THIS SYSTEM WILL BE SUBTLE/WEAK AND
THEREFORE THE QPF FORECASTS ARE ON THE LOW SIDE DUE TO THE LACK OF
LOW LEVEL FOCUS.
MODEL AGREEMENT ENDS THERE AS THE NEXT STORM SYSTEM/UPPER LOW COMES
INTO THE SOUTHERN ROCKIES BY TUESDAY. THE GFS SIMPLY KEEPS THE LOW
CHUGGING INTO THE PLAINS AND THROUGH THE MIDWEST ON WEDNESDAY...
WHILE THE ECMWF HOLDS IT BACK WELL TO THE WEST THROUGH THIS PERIOD.
SOME OF THE AUTOMATED POP GUIDANCE IS OBVIOUSLY WEIGHTED TOWARD THE
GFS...WITH LIKELY POPS ON WEDNESDAY. USUALLY...SLOWER IS BETTER WITH
SOUTHWESTERN UPPER LOWS...SO WILL KNOCK DOWN POPS INTO THE CHANCE
RANGE. POPS MAY BE DELAYED EVEN FURTHER IF THE ECMWF ENDS UP BEING
THE WINNING MODEL.
04
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1128 AM EST THU FEB 9 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
QUIET WEATHER CAN BE EXPECTED INTO FRIDAY. HOWEVER...THE WEATHER
PATTERN WILL CHANGE AS A BROAD UPPER LEVEL TROUGH TRACKS ACROSS
THE UPPER MIDWEST AND GREAT LAKES REGION. ITS ASSOCIATED COLD
FRONT WILL BRING A CHANCE OF SNOW TO CENTRAL INDIANA ON FRIDAY
ALONG WITH MUCH COLDER AIR. SNOW ACCUMULATIONS WILL BE NONE TO
MINIMAL...BUT FRIGID TEMPS WILL LINGER OVER THE AREA INTO MONDAY.
AFTER THAT...WINDS WILL BECOME SOUTHERLY AND ADVECT WARMER TEMPS
INTO CENTRAL INDIANA. AS A RESULT...WHEN THE NEXT DISTURBANCE
MOVES IN ON MONDAY...PRECIP WILL GENERALLY BE IN THE FORM OF A
RAIN/SNOW MIXTURE.
&&
.NEAR TERM /REST OF TODAY/...
UPDATED TO SIGNIFICANTLY INCREASE CLOUD COVER AND AS A
RESULT...LOWER TEMPERATURES ACROSS THE BOARD ABOUT 2 TO 5 DEGREES.
PERSISTENT STRATUS DECK THAT WAS ORIGINALLY EXPECTED TO BEGIN
DISSIPATING WITH THE ENCROACHMENT OF DRIER HIGH PRESSURE...HAS
ACTUALLY EXPANDED ON ITS NORTHERN FRINGE THIS MORNING. ADDITIONAL
STRATUS TO THE WEST IS ALSO BUILDING TOWARD THE AREA FASTER THAN
EXPECTED.
THAT SAID...EDGES ARE THINNER AND TAKING ON A MORE DIURNAL
APPEARANCE ON SATELLITE...AND COUPLED WITH A SLOT OF CLEAR SKIES
TO THE WEST...MAY SEE CLEARING IN THE NORTHWEST AND FAR WESTERN
FRINGE OF THE FORECAST AREA LATER THIS AFTERNOON. HOWEVER MOST OF
THE AREA SHOULD REMAIN AT LEAST MOSTLY CLOUDY.
TEMPS HAVE OBVIOUSLY BEEN IMPACTED BY THIS...AND HOURLY NUMERICAL
GUIDANCE INDICATES AT LEAST A COUPLE DEGREE DECREASE IS IN ORDER.
DECREASED MORE SIGNIFICANTLY IN AREAS EXPECTED TO REMAIN CLOUDY.
ALSO INSERTED A FLURRIES MENTION AS A FEW FLAKES HAVE BEEN FLYING
AT INDY...AND A SPIT OF SNOW CANNOT BE RULED OUT THROUGH THE DAY.
HOWEVER...THIS LITERALLY AMOUNTS TO ONLY A FEW FLAKES AND ZERO
SIGNIFICANCE IS EXPECTED FROM THIS.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY/...
THE MAIN FOCUS OF THE SHORT TERM IS PRECIP CHANCES ON
FRIDAY/FRIDAY NIGHT ASSOCIATED WITH A BROAD UPPER LEVEL LOW.
ASSOCIATED COLD FRONT WILL APPROACH NORTHWEST INDIANA AROUND
FRIDAY 12Z. HELD OFF ON PRECIP UNTIL CLOSER TO THE FRI 18Z TIME
FRAME...WHICH MODEL BLEND IS INDICATING. SO...ONLY WENT WITH
SLIGHT CHANCE POPS ACROSS WESTERN 2/3 OF FORECAST AREA FROM FRI
12-18Z. TEMPS SHOULD STILL BE COOL ENOUGH AT THAT TIME FOR SNOW
OVER ALL OF FORECAST AREA EXCEPT THE SOUTHERN THIRD WHICH CAN
EXPECT A RAIN/SNOW MIXTURE. HOWEVER...AS TEMPS INCREASE FROM
DIURNAL HEATING DURING THE FRI 18-22Z TIME FRAME...THE RAIN/SNOW MIX
LINE WILL MOVE FURTHER NORTH...ENCOMPASSING ALL BUT THE NORTHERN
THIRD OF THE FORECAST AREA THROUGH THE AFTERNOON HOURS. THIS ALSO
HAPPENS TO BE WHEN THE BULK OF THE MOISTURE SHOULD MOVE
THROUGH...SO THIS WILL CUT BACK ON CHANCES FOR SNOW ACCUMULATION.
AFTER THAT...TEMPS WILL QUICKLY PLUMMET BEHIND COLD FRONT...AND
PRECIP WILL TRANSITION BACK TO ALL SNOW ACROSS ENTIRE FORECAST
AREA FROM SAT 00Z ON. HOWEVER...AMOUNTS WILL BE LESS THAN A HALF
OF AN AS MOISTURE BECOMES MORE LIMITED.
HELD ONTO CHANCE POPS THROUGH FRIDAY NIGHT DUE TO ANY ADDITIONAL
FORCING WITH PASSAGE OF UPPER LEVEL LOW...BUT SNOW WILL BE OUT OF
THE AREA ENTIRELY BY SAT 12Z...AND THE REMAINDER OF SHORT TERM
PERIOD WILL BE DRY AND COLD AS HIGH PRESSURE RE-ESTABLISHES ITSELF
OVER CENTRAL INDIANA.
TEMPS...WENT WITH A BLEND EXCEPT FOR TOMORROW NIGHT...TRENDED
TOWARD THE WARMER NAM DUE TO MOSTLY CLOUDY SKIES. IN
ADDITION...TRENDED VERY LOW ON SATURDAY NIGHT WITH THE CLEAR SKIES
AND DEEP COLD POST FRONTAL AIR.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
DRY YET CHILLY WEATHER WILL CONTINUE TO WRAP UP THE WEEKEND AS A
LARGE AREA OF HIGH PRESSURE BLANKETS THE OHIO VALLEY. BROAD
SUBSIDENCE WILL ENSURE MAINLY SUNNY SKIES WITH A SLOW RISE IN TEMPS
THROUGH MONDAY AS WARM ADVECTION COMMENCES. DESPITE THE
SUNSHINE...THICKNESSES SUPPORT HIGHS REMAINING IN THE UPPER 20S AND
LOWER 30S SUNDAY...WITH HIGHS MODERATING INTO THE MID AND UPPER 30S
FOR MONDAY AS THE HIGH SHIFTS EAST AND RETURN SOUTHERLY FLOW
DEVELOPS.
EXTENDED MODELS REMAIN LARGELY IN GOOD AGREEMENT ON THE ARRIVAL OF
AN UPPER LEVEL DISTURBANCE MONDAY NIGHT/TUESDAY WITH ONLY THE GGEM
LAGGING THE FEATURE DUE TO INCREASED PHASING ALOFT. HAVE LEANED
CLOSER TO ECMWF WHICH HAS REMAINED CONSISTENT OVER THE LAST FEW RUNS
IN LOWER LEVELS COOLING SUFFICIENTLY ENOUGH MONDAY NIGHT FOR PRECIP
TO FALL AS LIGHT SNOW. COULD SEE SOME RAIN MIX IN WITH THE SNOW OVER
FAR SOUTHERN PORTIONS OF THE FORECAST AREA...BUT UNCERTAINTY IN THAT
HAPPENING RIGHT NOW IS HIGH ENOUGH TO KEEP A MIX MENTION OUT OF THE
FORECAST UNTIL TUESDAY AS TEMPS WARM. WILL MAINTAIN CHANCE POPS
THROUGH THIS TIMEFRAME.
SOME TIMING DIFFERENCES DEVELOP FROM THIS POINT FORWARD AS OP GFS
AND ECMWF ARE HANDLING THE EJECTION OF ENERGY OUT OF THE DEVELOPING
PACIFIC COAST TROUGH IN DIFFERENT WAYS. GROWING CONFIDENCE IN HIGH
PRESSURE BRIEFLY REESTABLISHING OVER THE OHIO VALLEY TUESDAY NIGHT
AND WEDNESDAY BEHIND THE LEAD UPPER WAVE AND HAVE CUT ALLBLEND POPS
SUBSTANTIALLY AS A RESULT. THE ARRIVAL OF THE UPPER ENERGY FROM THE
WESTERN TROUGH WILL SPUR A SURFACE WAVE TRAVERSING THE OHIO VALLEY
LATE WEDNESDAY INTO THURSDAY. AT THIS POINT IN TIME...APPEARS LOW
LEVEL THICKNESSES AND SURFACE TEMPS WARM ENOUGH TO SUPPORT MAINLY
RAIN FOR MUCH OF THE FORECAST AREA. UNTIL EXTENDED GUIDANCE CAN COME
INTO ALIGNMENT WITH REGARDS TO TRACK AND TIMING OF THE LOW...WILL BE
DIFFICULT TO EMPLOY MUCH ADDITIONAL DETAIL. WILL CARRY CHANCE POPS
WEDNESDAY NIGHT AND THURSDAY WITH TEMPS LIKELY WARMING INTO THE 40S.
&&
.AVIATION /DISCUSSION FOR 091200Z TAF ISSUANCE/...
1620Z UPDATE...BASED ON LATEST SAGGING TRENDS HAVE HELD ONTO
STRATO CU DECK MUCH LONGER THAN ORIGINALLY ANTICIPATED...WITH AT
BEST IT BEGINNING TO MIX OUT LATE THIS AFTERNOON. PREVIOUS DISCS
FOLLOW.
1430Z TAF UPDATE...STRATO CU DECK APPEARS TO BE RIGHT ON TRACK TO
MIX OUT AROUND 16Z THIS AFTERNOON. MADE FEW OR MINOR CHANGES TO
TAFS ATTM. PREVIOUS DISCUSSION FOLLOWS...
STUBBORN STRATOCU DECK HAS STOPPED ITS SOUTHWARD PROGRESS AND
ACTUALLY EVEN DRIFTED BACK NORTH A BIT OVER THE LAST FEW HOURS.
CEILINGS ARE HOVERING RIGHT AROUND 3KFT WITH OBS SHOWING SPORADIC
DROPS INTO MVFR CATEGORY. LOOKING AT RUC SOUNDINGS AND LOW LEVEL RH
PROGS...HAVE DELAYED CLEARING AT KHUF AND KIND UNTIL CLOSER TO
MIDDAY AND NOT UNTIL 18Z AT KBMG. WILL HAVE TO WATCH THIS MORNING
AT KLAF AS BACK EDGE OF THE CLOUD DECK MAY SLIP BACK ACROSS THE
TAF SITE FOR A SHORT PERIOD OF TIME.
SHOULD SEE LOWER CLOUDS FINALLY MIX OUT DURING THE AFTERNOON AS
WINDS BACK TO A W/SW DIRECTION. SKIES WILL STAY MAINLY CLEAR INTO
THE EVENING UNTIL A MORE SIGNIFICANT PUSH OF MOISTURE INTO THE
REGION LATE AHEAD OF AN APPROACHING COLD FRONT. WILL SEE VFR
STRATOCU REDEVELOP AFTER MIDNIGHT WITH CEILINGS AT 5-7KFT. WINDS
WILL BACK TO LIGHT S/SW TONIGHT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...TDUD
NEAR TERM...NIELD
SHORT TERM...TDUD
LONG TERM....RYAN
AVIATION...SMF
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1117 AM EST THU FEB 9 2012
.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
QUIET WEATHER CAN BE EXPECTED INTO FRIDAY. HOWEVER...THE WEATHER
PATTERN WILL CHANGE AS A BROAD UPPER LEVEL TROUGH TRACKS ACROSS
THE UPPER MIDWEST AND GREAT LAKES REGION. ITS ASSOCIATED COLD
FRONT WILL BRING A CHANCE OF SNOW TO CENTRAL INDIANA ON FRIDAY
ALONG WITH MUCH COLDER AIR. SNOW ACCUMULATIONS WILL BE NONE TO
MINIMAL...BUT FRIGID TEMPS WILL LINGER OVER THE AREA INTO MONDAY.
AFTER THAT...WINDS WILL BECOME SOUTHERLY AND ADVECT WARMER TEMPS
INTO CENTRAL INDIANA. AS A RESULT...WHEN THE NEXT DISTURBANCE
MOVES IN ON MONDAY...PRECIP WILL GENERALLY BE IN THE FORM OF A
RAIN/SNOW MIXTURE.
&&
.NEAR TERM /REST OF TODAY/...
UPDATED TO SIGNIFICANTLY INCREASE CLOUD COVER AND AS A
RESULT...LOWER TEMPERATURES ACROSS THE BOARD ABOUT 2 TO 5 DEGREES.
PERSISTENT STRATUS DECK THAT WAS ORIGINALLY EXPECTED TO BEGIN
DISSIPATING WITH THE ENCROACHMENT OF DRIER HIGH PRESSURE...HAS
ACTUALLY EXPANDED ON ITS NORTHERN FRINGE THIS MORNING. ADDITIONAL
STRATUS TO THE WEST IS ALSO BUILDING TOWARD THE AREA FASTER THAN
EXPECTED.
THAT SAID...EDGES ARE THINNER AND TAKING ON A MORE DIURNAL
APPEARANCE ON SATELLITE...AND COUPLED WITH A SLOT OF CLEAR SKIES
TO THE WEST...MAY SEE CLEARING IN THE NORTHWEST AND FAR WESTERN
FRINGE OF THE FORECAST AREA LATER THIS AFTERNOON. HOWEVER MOST OF
THE AREA SHOULD REMAIN AT LEAST MOSTLY CLOUDY.
TEMPS HAVE OBVIOUSLY BEEN IMPACTED BY THIS...AND HOURLY NUMERICAL
GUIDANCE INDICATES AT LEAST A COUPLE DEGREE DECREASE IS IN ORDER.
DECREASED MORE SIGNIFICANTLY IN AREAS EXPECTED TO REMAIN CLOUDY.
ALSO INSERTED A FLURRIES MENTION AS A FEW FLAKES HAVE BEEN FLYING
AT INDY...AND A SPIT OF SNOW CANNOT BE RULED OUT THROUGH THE DAY.
HOWEVER...THIS LITERALLY AMOUNTS TO ONLY A FEW FLAKES AND ZERO
SIGNIFICANCE IS EXPECTED FROM THIS.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY/...
THE MAIN FOCUS OF THE SHORT TERM IS PRECIP CHANCES ON
FRIDAY/FRIDAY NIGHT ASSOCIATED WITH A BROAD UPPER LEVEL LOW.
ASSOCIATED COLD FRONT WILL APPROACH NORTHWEST INDIANA AROUND
FRIDAY 12Z. HELD OFF ON PRECIP UNTIL CLOSER TO THE FRI 18Z TIME
FRAME...WHICH MODEL BLEND IS INDICATING. SO...ONLY WENT WITH
SLIGHT CHANCE POPS ACROSS WESTERN 2/3 OF FORECAST AREA FROM FRI
12-18Z. TEMPS SHOULD STILL BE COOL ENOUGH AT THAT TIME FOR SNOW
OVER ALL OF FORECAST AREA EXCEPT THE SOUTHERN THIRD WHICH CAN
EXPECT A RAIN/SNOW MIXTURE. HOWEVER...AS TEMPS INCREASE FROM
DIURNAL HEATING DURING THE FRI 18-22Z TIME FRAME...THE RAIN/SNOW MIX
LINE WILL MOVE FURTHER NORTH...ENCOMPASSING ALL BUT THE NORTHERN
THIRD OF THE FORECAST AREA THROUGH THE AFTERNOON HOURS. THIS ALSO
HAPPENS TO BE WHEN THE BULK OF THE MOISTURE SHOULD MOVE
THROUGH...SO THIS WILL CUT BACK ON CHANCES FOR SNOW ACCUMULATION.
AFTER THAT...TEMPS WILL QUICKLY PLUMMET BEHIND COLD FRONT...AND
PRECIP WILL TRANSITION BACK TO ALL SNOW ACROSS ENTIRE FORECAST
AREA FROM SAT 00Z ON. HOWEVER...AMOUNTS WILL BE LESS THAN A HALF
OF AN AS MOISTURE BECOMES MORE LIMITED.
HELD ONTO CHANCE POPS THROUGH FRIDAY NIGHT DUE TO ANY ADDITIONAL
FORCING WITH PASSAGE OF UPPER LEVEL LOW...BUT SNOW WILL BE OUT OF
THE AREA ENTIRELY BY SAT 12Z...AND THE REMAINDER OF SHORT TERM
PERIOD WILL BE DRY AND COLD AS HIGH PRESSURE RE-ESTABLISHES ITSELF
OVER CENTRAL INDIANA.
TEMPS...WENT WITH A BLEND EXCEPT FOR TOMORROW NIGHT...TRENDED
TOWARD THE WARMER NAM DUE TO MOSTLY CLOUDY SKIES. IN
ADDITION...TRENDED VERY LOW ON SATURDAY NIGHT WITH THE CLEAR SKIES
AND DEEP COLD POST FRONTAL AIR.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
DRY YET CHILLY WEATHER WILL CONTINUE TO WRAP UP THE WEEKEND AS A
LARGE AREA OF HIGH PRESSURE BLANKETS THE OHIO VALLEY. BROAD
SUBSIDENCE WILL ENSURE MAINLY SUNNY SKIES WITH A SLOW RISE IN TEMPS
THROUGH MONDAY AS WARM ADVECTION COMMENCES. DESPITE THE
SUNSHINE...THICKNESSES SUPPORT HIGHS REMAINING IN THE UPPER 20S AND
LOWER 30S SUNDAY...WITH HIGHS MODERATING INTO THE MID AND UPPER 30S
FOR MONDAY AS THE HIGH SHIFTS EAST AND RETURN SOUTHERLY FLOW
DEVELOPS.
EXTENDED MODELS REMAIN LARGELY IN GOOD AGREEMENT ON THE ARRIVAL OF
AN UPPER LEVEL DISTURBANCE MONDAY NIGHT/TUESDAY WITH ONLY THE GGEM
LAGGING THE FEATURE DUE TO INCREASED PHASING ALOFT. HAVE LEANED
CLOSER TO ECMWF WHICH HAS REMAINED CONSISTENT OVER THE LAST FEW RUNS
IN LOWER LEVELS COOLING SUFFICIENTLY ENOUGH MONDAY NIGHT FOR PRECIP
TO FALL AS LIGHT SNOW. COULD SEE SOME RAIN MIX IN WITH THE SNOW OVER
FAR SOUTHERN PORTIONS OF THE FORECAST AREA...BUT UNCERTAINTY IN THAT
HAPPENING RIGHT NOW IS HIGH ENOUGH TO KEEP A MIX MENTION OUT OF THE
FORECAST UNTIL TUESDAY AS TEMPS WARM. WILL MAINTAIN CHANCE POPS
THROUGH THIS TIMEFRAME.
SOME TIMING DIFFERENCES DEVELOP FROM THIS POINT FORWARD AS OP GFS
AND ECMWF ARE HANDLING THE EJECTION OF ENERGY OUT OF THE DEVELOPING
PACIFIC COAST TROUGH IN DIFFERENT WAYS. GROWING CONFIDENCE IN HIGH
PRESSURE BRIEFLY REESTABLISHING OVER THE OHIO VALLEY TUESDAY NIGHT
AND WEDNESDAY BEHIND THE LEAD UPPER WAVE AND HAVE CUT ALLBLEND POPS
SUBSTANTIALLY AS A RESULT. THE ARRIVAL OF THE UPPER ENERGY FROM THE
WESTERN TROUGH WILL SPUR A SURFACE WAVE TRAVERSING THE OHIO VALLEY
LATE WEDNESDAY INTO THURSDAY. AT THIS POINT IN TIME...APPEARS LOW
LEVEL THICKNESSES AND SURFACE TEMPS WARM ENOUGH TO SUPPORT MAINLY
RAIN FOR MUCH OF THE FORECAST AREA. UNTIL EXTENDED GUIDANCE CAN COME
INTO ALIGNMENT WITH REGARDS TO TRACK AND TIMING OF THE LOW...WILL BE
DIFFICULT TO EMPLOY MUCH ADDITIONAL DETAIL. WILL CARRY CHANCE POPS
WEDNESDAY NIGHT AND THURSDAY WITH TEMPS LIKELY WARMING INTO THE 40S.
&&
.AVIATION /DISCUSSION FOR 091200Z TAF ISSUANCE/...
1430Z TAF UPDATE...STRATO CU DECK APPEARS TO BE RIGHT ON TRACK TO
MIX OUT AROUND 16Z THIS AFTERNOON. MADE FEW OR MINOR CHANGES TO
TAFS ATTM. PREVIOUS DISCUSSION FOLLOWS...
STUBBORN STRATOCU DECK HAS STOPPED ITS SOUTHWARD PROGRESS AND
ACTUALLY EVEN DRIFTED BACK NORTH A BIT OVER THE LAST FEW HOURS.
CEILINGS ARE HOVERING RIGHT AROUND 3KFT WITH OBS SHOWING SPORADIC
DROPS INTO MVFR CATEGORY. LOOKING AT RUC SOUNDINGS AND LOW LEVEL RH
PROGS...HAVE DELAYED CLEARING AT KHUF AND KIND UNTIL CLOSER TO
MIDDAY AND NOT UNTIL 18Z AT KBMG. WILL HAVE TO WATCH THIS MORNING
AT KLAF AS BACK EDGE OF THE CLOUD DECK MAY SLIP BACK ACROSS THE
TAF SITE FOR A SHORT PERIOD OF TIME.
SHOULD SEE LOWER CLOUDS FINALLY MIX OUT DURING THE AFTERNOON AS
WINDS BACK TO A W/SW DIRECTION. SKIES WILL STAY MAINLY CLEAR INTO
THE EVENING UNTIL A MORE SIGNIFICANT PUSH OF MOISTURE INTO THE
REGION LATE AHEAD OF AN APPROACHING COLD FRONT. WILL SEE VFR
STRATOCU REDEVELOP AFTER MIDNIGHT WITH CEILINGS AT 5-7KFT. WINDS
WILL BACK TO LIGHT S/SW TONIGHT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...TDUD
NEAR TERM...NIELD
SHORT TERM...TDUD
LONG TERM....RYAN
AVIATION...SMF
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
930 AM EST THU FEB 9 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
QUIET WEATHER CAN BE EXPECTED INTO FRIDAY. HOWEVER...THE WEATHER
PATTERN WILL CHANGE AS A BROAD UPPER LEVEL TROUGH TRACKS ACROSS
THE UPPER MIDWEST AND GREAT LAKES REGION. ITS ASSOCIATED COLD
FRONT WILL BRING A CHANCE OF SNOW TO CENTRAL INDIANA ON FRIDAY
ALONG WITH MUCH COLDER AIR. SNOW ACCUMULATIONS WILL BE NONE TO
MINIMAL...BUT FRIGID TEMPS WILL LINGER OVER THE AREA INTO MONDAY.
AFTER THAT...WINDS WILL BECOME SOUTHERLY AND ADVECT WARMER TEMPS
INTO CENTRAL INDIANA. AS A RESULT...WHEN THE NEXT DISTURBANCE
MOVES IN ON MONDAY...PRECIP WILL GENERALLY BE IN THE FORM OF A
RAIN/SNOW MIXTURE.
&&
.NEAR TERM /THIS MORNING AND TODAY/...
CALM CONDITIONS CAN BE EXPECTED THROUGH TODAY AS HIGH PRESSURE
BUILDS ACROSS CENTRAL INDIANA. SKIES ARE CURRENTLY BEGINNING TO
CLEAR OUT ACROSS THE NORTHWEST QUADRANT OF FORECAST AREA FROM
YESTERDAY/S DISTURBANCE. THIS CLEARING WILL SPREAD FROM NORTHWEST
TO SOUTHEAST OVER THE NEXT SEVERAL HOURS...EVENTUALLY RESULTING IN
CLEAR SKIES ACROSS ENTIRE FORECAST AREA SHORTLY AFTER DAYBREAK.
TEMPS WILL TOP OFF IN THE UPPER 30S/LOW 40S. LEANED TOWARD THE
WARMER NAM DUE TO AMPLE SUNSHINE AND A RETURN TO SOUTHWESTERLY
FLOW. CURRENTLY...TEMPS ACROSS CENTRAL INDIANA ARE RANGING FROM THE
LOW TO MID 20S WHERE CLEARING HAS ALREADY OCCURRED...TO LOW 30S
ACROSS THE SOUTHERN COUNTIES STILL UNDER CLOUD COVER. DEWPOINTS
ARE IN THE LOW 20S AND WINDS ARE LIGHT AND VARIABLE.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY/...
THE MAIN FOCUS OF THE SHORT TERM IS PRECIP CHANCES ON
FRIDAY/FRIDAY NIGHT ASSOCIATED WITH A BROAD UPPER LEVEL LOW.
ASSOCIATED COLD FRONT WILL APPROACH NORTHWEST INDIANA AROUND
FRIDAY 12Z. HELD OFF ON PRECIP UNTIL CLOSER TO THE FRI 18Z TIME
FRAME...WHICH MODEL BLEND IS INDICATING. SO...ONLY WENT WITH
SLIGHT CHANCE POPS ACROSS WESTERN 2/3 OF FORECAST AREA FROM FRI
12-18Z. TEMPS SHOULD STILL BE COOL ENOUGH AT THAT TIME FOR SNOW
OVER ALL OF FORECAST AREA EXCEPT THE SOUTHERN THIRD WHICH CAN
EXPECT A RAIN/SNOW MIXTURE. HOWEVER...AS TEMPS INCREASE FROM
DIURNAL HEATING DURING THE FRI 18-22Z TIME FRAME...THE RAIN/SNOW MIX
LINE WILL MOVE FURTHER NORTH...ENCOMPASSING ALL BUT THE NORTHERN
THIRD OF THE FORECAST AREA THROUGH THE AFTERNOON HOURS. THIS ALSO
HAPPENS TO BE WHEN THE BULK OF THE MOISTURE SHOULD MOVE
THROUGH...SO THIS WILL CUT BACK ON CHANCES FOR SNOW ACCUMULATION.
AFTER THAT...TEMPS WILL QUICKLY PLUMMET BEHIND COLD FRONT...AND
PRECIP WILL TRANSITION BACK TO ALL SNOW ACROSS ENTIRE FORECAST
AREA FROM SAT 00Z ON. HOWEVER...AMOUNTS WILL BE LESS THAN A HALF
OF AN AS MOISTURE BECOMES MORE LIMITED.
HELD ONTO CHANCE POPS THROUGH FRIDAY NIGHT DUE TO ANY ADDITIONAL
FORCING WITH PASSAGE OF UPPER LEVEL LOW...BUT SNOW WILL BE OUT OF
THE AREA ENTIRELY BY SAT 12Z...AND THE REMAINDER OF SHORT TERM
PERIOD WILL BE DRY AND COLD AS HIGH PRESSURE RE-ESTABLISHES ITSELF
OVER CENTRAL INDIANA.
TEMPS...WENT WITH A BLEND EXCEPT FOR TOMORROW NIGHT...TRENDED
TOWARD THE WARMER NAM DUE TO MOSTLY CLOUDY SKIES. IN
ADDITION...TRENDED VERY LOW ON SATURDAY NIGHT WITH THE CLEAR SKIES
AND DEEP COLD POST FRONTAL AIR.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
DRY YET CHILLY WEATHER WILL CONTINUE TO WRAP UP THE WEEKEND AS A
LARGE AREA OF HIGH PRESSURE BLANKETS THE OHIO VALLEY. BROAD
SUBSIDENCE WILL ENSURE MAINLY SUNNY SKIES WITH A SLOW RISE IN TEMPS
THROUGH MONDAY AS WARM ADVECTION COMMENCES. DESPITE THE
SUNSHINE...THICKNESSES SUPPORT HIGHS REMAINING IN THE UPPER 20S AND
LOWER 30S SUNDAY...WITH HIGHS MODERATING INTO THE MID AND UPPER 30S
FOR MONDAY AS THE HIGH SHIFTS EAST AND RETURN SOUTHERLY FLOW
DEVELOPS.
EXTENDED MODELS REMAIN LARGELY IN GOOD AGREEMENT ON THE ARRIVAL OF
AN UPPER LEVEL DISTURBANCE MONDAY NIGHT/TUESDAY WITH ONLY THE GGEM
LAGGING THE FEATURE DUE TO INCREASED PHASING ALOFT. HAVE LEANED
CLOSER TO ECMWF WHICH HAS REMAINED CONSISTENT OVER THE LAST FEW RUNS
IN LOWER LEVELS COOLING SUFFICIENTLY ENOUGH MONDAY NIGHT FOR PRECIP
TO FALL AS LIGHT SNOW. COULD SEE SOME RAIN MIX IN WITH THE SNOW OVER
FAR SOUTHERN PORTIONS OF THE FORECAST AREA...BUT UNCERTAINTY IN THAT
HAPPENING RIGHT NOW IS HIGH ENOUGH TO KEEP A MIX MENTION OUT OF THE
FORECAST UNTIL TUESDAY AS TEMPS WARM. WILL MAINTAIN CHANCE POPS
THROUGH THIS TIMEFRAME.
SOME TIMING DIFFERENCES DEVELOP FROM THIS POINT FORWARD AS OP GFS
AND ECMWF ARE HANDLING THE EJECTION OF ENERGY OUT OF THE DEVELOPING
PACIFIC COAST TROUGH IN DIFFERENT WAYS. GROWING CONFIDENCE IN HIGH
PRESSURE BRIEFLY REESTABLISHING OVER THE OHIO VALLEY TUESDAY NIGHT
AND WEDNESDAY BEHIND THE LEAD UPPER WAVE AND HAVE CUT ALLBLEND POPS
SUBSTANTIALLY AS A RESULT. THE ARRIVAL OF THE UPPER ENERGY FROM THE
WESTERN TROUGH WILL SPUR A SURFACE WAVE TRAVERSING THE OHIO VALLEY
LATE WEDNESDAY INTO THURSDAY. AT THIS POINT IN TIME...APPEARS LOW
LEVEL THICKNESSES AND SURFACE TEMPS WARM ENOUGH TO SUPPORT MAINLY
RAIN FOR MUCH OF THE FORECAST AREA. UNTIL EXTENDED GUIDANCE CAN COME
INTO ALIGNMENT WITH REGARDS TO TRACK AND TIMING OF THE LOW...WILL BE
DIFFICULT TO EMPLOY MUCH ADDITIONAL DETAIL. WILL CARRY CHANCE POPS
WEDNESDAY NIGHT AND THURSDAY WITH TEMPS LIKELY WARMING INTO THE 40S.
&&
.AVIATION /DISCUSSION FOR 091200Z TAF ISSUANCE/...
1430Z TAF UPDATE...STRATO CU DECK APPEARS TO BE RIGHT ON TRACK TO
MIX OUT AROUND 16Z THIS AFTERNOON. MADE FEW OR MINOR CHANGES TO
TAFS ATTM. PREVIOUS DISCUSSION FOLLOWS...
STUBBORN STRATOCU DECK HAS STOPPED ITS SOUTHWARD PROGRESS AND
ACTUALLY EVEN DRIFTED BACK NORTH A BIT OVER THE LAST FEW HOURS.
CEILINGS ARE HOVERING RIGHT AROUND 3KFT WITH OBS SHOWING SPORADIC
DROPS INTO MVFR CATEGORY. LOOKING AT RUC SOUNDINGS AND LOW LEVEL RH
PROGS...HAVE DELAYED CLEARING AT KHUF AND KIND UNTIL CLOSER TO
MIDDAY AND NOT UNTIL 18Z AT KBMG. WILL HAVE TO WATCH THIS MORNING
AT KLAF AS BACK EDGE OF THE CLOUD DECK MAY SLIP BACK ACROSS THE
TAF SITE FOR A SHORT PERIOD OF TIME.
SHOULD SEE LOWER CLOUDS FINALLY MIX OUT DURING THE AFTERNOON AS
WINDS BACK TO A W/SW DIRECTION. SKIES WILL STAY MAINLY CLEAR INTO
THE EVENING UNTIL A MORE SIGNIFICANT PUSH OF MOISTURE INTO THE
REGION LATE AHEAD OF AN APPROACHING COLD FRONT. WILL SEE VFR
STRATOCU REDEVELOP AFTER MIDNIGHT WITH CEILINGS AT 5-7KFT. WINDS
WILL BACK TO LIGHT S/SW TONIGHT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...TDUD
NEAR TERM...TDUD
SHORT TERM...TDUD
LONG TERM....RYAN
AVIATION...SMF
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
619 AM EST THU FEB 9 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
QUIET WEATHER CAN BE EXPECTED INTO FRIDAY. HOWEVER...THE WEATHER
PATTERN WILL CHANGE AS A BROAD UPPER LEVEL TROUGH TRACKS ACROSS
THE UPPER MIDWEST AND GREAT LAKES REGION. ITS ASSOCIATED COLD
FRONT WILL BRING A CHANCE OF SNOW TO CENTRAL INDIANA ON FRIDAY
ALONG WITH MUCH COLDER AIR. SNOW ACCUMULATIONS WILL BE NONE TO
MINIMAL...BUT FRIGID TEMPS WILL LINGER OVER THE AREA INTO MONDAY.
AFTER THAT...WINDS WILL BECOME SOUTHERLY AND ADVECT WARMER TEMPS
INTO CENTRAL INDIANA. AS A RESULT...WHEN THE NEXT DISTURBANCE
MOVES IN ON MONDAY...PRECIP WILL GENERALLY BE IN THE FORM OF A
RAIN/SNOW MIXTURE.
&&
.NEAR TERM /THIS MORNING AND TODAY/...
CALM CONDITIONS CAN BE EXPECTED THROUGH TODAY AS HIGH PRESSURE
BUILDS ACROSS CENTRAL INDIANA. SKIES ARE CURRENTLY BEGINNING TO
CLEAR OUT ACROSS THE NORTHWEST QUADRANT OF FORECAST AREA FROM
YESTERDAY/S DISTURBANCE. THIS CLEARING WILL SPREAD FROM NORTHWEST
TO SOUTHEAST OVER THE NEXT SEVERAL HOURS...EVENTUALLY RESULTING IN
CLEAR SKIES ACROSS ENTIRE FORECAST AREA SHORTLY AFTER DAYBREAK.
TEMPS WILL TOP OFF IN THE UPPER 30S/LOW 40S. LEANED TOWARD THE
WARMER NAM DUE TO AMPLE SUNSHINE AND A RETURN TO SOUTHWESTERLY
FLOW. CURRENTLY...TEMPS ACROSS CENTRAL INDIANA ARE RANGING FROM THE
LOW TO MID 20S WHERE CLEARING HAS ALREADY OCCURRED...TO LOW 30S
ACROSS THE SOUTHERN COUNTIES STILL UNDER CLOUD COVER. DEWPOINTS
ARE IN THE LOW 20S AND WINDS ARE LIGHT AND VARIABLE.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY/...
THE MAIN FOCUS OF THE SHORT TERM IS PRECIP CHANCES ON
FRIDAY/FRIDAY NIGHT ASSOCIATED WITH A BROAD UPPER LEVEL LOW.
ASSOCIATED COLD FRONT WILL APPROACH NORTHWEST INDIANA AROUND
FRIDAY 12Z. HELD OFF ON PRECIP UNTIL CLOSER TO THE FRI 18Z TIME
FRAME...WHICH MODEL BLEND IS INDICATING. SO...ONLY WENT WITH
SLIGHT CHANCE POPS ACROSS WESTERN 2/3 OF FORECAST AREA FROM FRI
12-18Z. TEMPS SHOULD STILL BE COOL ENOUGH AT THAT TIME FOR SNOW
OVER ALL OF FORECAST AREA EXCEPT THE SOUTHERN THIRD WHICH CAN
EXPECT A RAIN/SNOW MIXTURE. HOWEVER...AS TEMPS INCREASE FROM
DIURNAL HEATING DURING THE FRI 18-22Z TIME FRAME...THE RAIN/SNOW MIX
LINE WILL MOVE FURTHER NORTH...ENCOMPASSING ALL BUT THE NORTHERN
THIRD OF THE FORECAST AREA THROUGH THE AFTERNOON HOURS. THIS ALSO
HAPPENS TO BE WHEN THE BULK OF THE MOISTURE SHOULD MOVE
THROUGH...SO THIS WILL CUT BACK ON CHANCES FOR SNOW ACCUMULATION.
AFTER THAT...TEMPS WILL QUICKLY PLUMMET BEHIND COLD FRONT...AND
PRECIP WILL TRANSITION BACK TO ALL SNOW ACROSS ENTIRE FORECAST
AREA FROM SAT 00Z ON. HOWEVER...AMOUNTS WILL BE LESS THAN A HALF
OF AN AS MOISTURE BECOMES MORE LIMITED.
HELD ONTO CHANCE POPS THROUGH FRIDAY NIGHT DUE TO ANY ADDITIONAL
FORCING WITH PASSAGE OF UPPER LEVEL LOW...BUT SNOW WILL BE OUT OF
THE AREA ENTIRELY BY SAT 12Z...AND THE REMAINDER OF SHORT TERM
PERIOD WILL BE DRY AND COLD AS HIGH PRESSURE RE-ESTABLISHES ITSELF
OVER CENTRAL INDIANA.
TEMPS...WENT WITH A BLEND EXCEPT FOR TOMORROW NIGHT...TRENDED
TOWARD THE WARMER NAM DUE TO MOSTLY CLOUDY SKIES. IN
ADDITION...TRENDED VERY LOW ON SATURDAY NIGHT WITH THE CLEAR SKIES
AND DEEP COLD POST FRONTAL AIR.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
DRY YET CHILLY WEATHER WILL CONTINUE TO WRAP UP THE WEEKEND AS A
LARGE AREA OF HIGH PRESSURE BLANKETS THE OHIO VALLEY. BROAD
SUBSIDENCE WILL ENSURE MAINLY SUNNY SKIES WITH A SLOW RISE IN TEMPS
THROUGH MONDAY AS WARM ADVECTION COMMENCES. DESPITE THE
SUNSHINE...THICKNESSES SUPPORT HIGHS REMAINING IN THE UPPER 20S AND
LOWER 30S SUNDAY...WITH HIGHS MODERATING INTO THE MID AND UPPER 30S
FOR MONDAY AS THE HIGH SHIFTS EAST AND RETURN SOUTHERLY FLOW
DEVELOPS.
EXTENDED MODELS REMAIN LARGELY IN GOOD AGREEMENT ON THE ARRIVAL OF
AN UPPER LEVEL DISTURBANCE MONDAY NIGHT/TUESDAY WITH ONLY THE GGEM
LAGGING THE FEATURE DUE TO INCREASED PHASING ALOFT. HAVE LEANED
CLOSER TO ECMWF WHICH HAS REMAINED CONSISTENT OVER THE LAST FEW RUNS
IN LOWER LEVELS COOLING SUFFICIENTLY ENOUGH MONDAY NIGHT FOR PRECIP
TO FALL AS LIGHT SNOW. COULD SEE SOME RAIN MIX IN WITH THE SNOW OVER
FAR SOUTHERN PORTIONS OF THE FORECAST AREA...BUT UNCERTAINTY IN THAT
HAPPENING RIGHT NOW IS HIGH ENOUGH TO KEEP A MIX MENTION OUT OF THE
FORECAST UNTIL TUESDAY AS TEMPS WARM. WILL MAINTAIN CHANCE POPS
THROUGH THIS TIMEFRAME.
SOME TIMING DIFFERENCES DEVELOP FROM THIS POINT FORWARD AS OP GFS
AND ECMWF ARE HANDLING THE EJECTION OF ENERGY OUT OF THE DEVELOPING
PACIFIC COAST TROUGH IN DIFFERENT WAYS. GROWING CONFIDENCE IN HIGH
PRESSURE BRIEFLY REESTABLISHING OVER THE OHIO VALLEY TUESDAY NIGHT
AND WEDNESDAY BEHIND THE LEAD UPPER WAVE AND HAVE CUT ALLBLEND POPS
SUBSTANTIALLY AS A RESULT. THE ARRIVAL OF THE UPPER ENERGY FROM THE
WESTERN TROUGH WILL SPUR A SURFACE WAVE TRAVERSING THE OHIO VALLEY
LATE WEDNESDAY INTO THURSDAY. AT THIS POINT IN TIME...APPEARS LOW
LEVEL THICKNESSES AND SURFACE TEMPS WARM ENOUGH TO SUPPORT MAINLY
RAIN FOR MUCH OF THE FORECAST AREA. UNTIL EXTENDED GUIDANCE CAN COME
INTO ALIGNMENT WITH REGARDS TO TRACK AND TIMING OF THE LOW...WILL BE
DIFFICULT TO EMPLOY MUCH ADDITIONAL DETAIL. WILL CARRY CHANCE POPS
WEDNESDAY NIGHT AND THURSDAY WITH TEMPS LIKELY WARMING INTO THE 40S.
&&
.AVIATION /DISCUSSION FOR 091200Z TAF ISSUANCE/...
STUBBORN STRATOCU DECK HAS STOPPED ITS SOUTHWARD PROGRESS AND
ACTUALLY EVEN DRIFTED BACK NORTH A BIT OVER THE LAST FEW HOURS.
CEILINGS ARE HOVERING RIGHT AROUND 3KFT WITH OBS SHOWING SPORADIC
DROPS INTO MVFR CATEGORY. LOOKING AT RUC SOUNDINGS AND LOW LEVEL RH
PROGS...HAVE DELAYED CLEARING AT KHUF AND KIND UNTIL CLOSER TO
MIDDAY AND NOT UNTIL 18Z AT KBMG. WILL HAVE TO WATCH THIS MORNING
AT KLAF AS BACK EDGE OF THE CLOUD DECK MAY SLIP BACK ACROSS THE
TAF SITE FOR A SHORT PERIOD OF TIME.
SHOULD SEE LOWER CLOUDS FINALLY MIX OUT DURING THE AFTERNOON AS
WINDS BACK TO A W/SW DIRECTION. SKIES WILL STAY MAINLY CLEAR INTO
THE EVENING UNTIL A MORE SIGNIFICANT PUSH OF MOISTURE INTO THE
REGION LATE AHEAD OF AN APPROACHING COLD FRONT. WILL SEE VFR
STRATOCU REDEVELOP AFTER MIDNIGHT WITH CEILINGS AT 5-7KFT. WINDS
WILL BACK TO LIGHT S/SW TONIGHT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...TDUD
NEAR TERM...TDUD
SHORT TERM...TDUD
LONG TERM....RYAN
AVIATION...RYAN
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
413 AM EST THU FEB 9 2012
.UPDATE...
THE SYNOPSIS...NEAR TERM...SHORT TERM
AND LONG TERM SECTIONS HAVE BEEN UPDATED BELOW
&&
.SYNOPSIS...
QUIET WEATHER CAN BE EXPECTED INTO FRIDAY. HOWEVER...THE WEATHER
PATTERN WILL CHANGE AS A BROAD UPPER LEVEL TROUGH TRACKS ACROSS
THE UPPER MIDWEST AND GREAT LAKES REGION. ITS ASSOCIATED COLD
FRONT WILL BRING A CHANCE OF SNOW TO CENTRAL INDIANA ON FRIDAY
ALONG WITH MUCH COLDER AIR. SNOW ACCUMULATIONS WILL BE NONE TO
MINIMAL...BUT FRIGID TEMPS WILL LINGER OVER THE AREA INTO MONDAY.
AFTER THAT...WINDS WILL BECOME SOUTHERLY AND ADVECT WARMER TEMPS
INTO CENTRAL INDIANA. AS A RESULT...WHEN THE NEXT DISTURBANCE
MOVES IN ON MONDAY...PRECIP WILL GENERALLY BE IN THE FORM OF A
RAIN/SNOW MIXTURE.
&&
.NEAR TERM /THIS MORNING AND TODAY/...
CALM CONDITIONS CAN BE EXPECTED THROUGH TODAY AS HIGH PRESSURE
BUILDS ACROSS CENTRAL INDIANA. SKIES ARE CURRENTLY BEGINNING TO
CLEAR OUT ACROSS THE NORTHWEST QUADRANT OF FORECAST AREA FROM
YESTERDAY/S DISTURBANCE. THIS CLEARING WILL SPREAD FROM NORTHWEST
TO SOUTHEAST OVER THE NEXT SEVERAL HOURS...EVENTUALLY RESULTING IN
CLEAR SKIES ACROSS ENTIRE FORECAST AREA SHORTLY AFTER DAYBREAK.
TEMPS WILL TOP OFF IN THE UPPER 30S/LOW 40S. LEANED TOWARD THE
WARMER NAM DUE TO AMPLE SUNSHINE AND A RETURN TO SOUTHWESTERLY
FLOW. CURRENTLY...TEMPS ACROSS CENTRAL INDIANA ARE RANGING FROM THE
LOW TO MID 20S WHERE CLEARING HAS ALREADY OCCURRED...TO LOW 30S
ACROSS THE SOUTHERN COUNTIES STILL UNDER CLOUD COVER. DEWPOINTS
ARE IN THE LOW 20S AND WINDS ARE LIGHT AND VARIABLE.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY/...
THE MAIN FOCUS OF THE SHORT TERM IS PRECIP CHANCES ON
FRIDAY/FRIDAY NIGHT ASSOCIATED WITH A BROAD UPPER LEVEL LOW.
ASSOCIATED COLD FRONT WILL APPROACH NORTHWEST INDIANA AROUND
FRIDAY 12Z. HELD OFF ON PRECIP UNTIL CLOSER TO THE FRI 18Z TIME
FRAME...WHICH MODEL BLEND IS INDICATING. SO...ONLY WENT WITH
SLIGHT CHANCE POPS ACROSS WESTERN 2/3 OF FORECAST AREA FROM FRI
12-18Z. TEMPS SHOULD STILL BE COOL ENOUGH AT THAT TIME FOR SNOW
OVER ALL OF FORECAST AREA EXCEPT THE SOUTHERN THIRD WHICH CAN
EXPECT A RAIN/SNOW MIXTURE. HOWEVER...AS TEMPS INCREASE FROM
DIURNAL HEATING DURING THE FRI 18-22Z TIME FRAME...THE RAIN/SNOW MIX
LINE WILL MOVE FURTHER NORTH...ENCOMPASSING ALL BUT THE NORTHERN
THIRD OF THE FORECAST AREA THROUGH THE AFTERNOON HOURS. THIS ALSO
HAPPENS TO BE WHEN THE BULK OF THE MOISTURE SHOULD MOVE
THROUGH...SO THIS WILL CUT BACK ON CHANCES FOR SNOW ACCUMULATION.
AFTER THAT...TEMPS WILL QUICKLY PLUMMET BEHIND COLD FRONT...AND
PRECIP WILL TRANSITION BACK TO ALL SNOW ACROSS ENTIRE FORECAST
AREA FROM SAT 00Z ON. HOWEVER...AMOUNTS WILL BE LESS THAN A HALF
OF AN AS MOISTURE BECOMES MORE LIMITED.
HELD ONTO CHANCE POPS THROUGH FRIDAY NIGHT DUE TO ANY ADDITIONAL
FORCING WITH PASSAGE OF UPPER LEVEL LOW...BUT SNOW WILL BE OUT OF
THE AREA ENTIRELY BY SAT 12Z...AND THE REMAINDER OF SHORT TERM
PERIOD WILL BE DRY AND COLD AS HIGH PRESSURE RE-ESTABLISHES ITSELF
OVER CENTRAL INDIANA.
TEMPS...WENT WITH A BLEND EXCEPT FOR TOMORROW NIGHT...TRENDED
TOWARD THE WARMER NAM DUE TO MOSTLY CLOUDY SKIES. IN
ADDITION...TRENDED VERY LOW ON SATURDAY NIGHT WITH THE CLEAR SKIES
AND DEEP COLD POST FRONTAL AIR.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
DRY YET CHILLY WEATHER WILL CONTINUE TO WRAP UP THE WEEKEND AS A
LARGE AREA OF HIGH PRESSURE BLANKETS THE OHIO VALLEY. BROAD
SUBSIDENCE WILL ENSURE MAINLY SUNNY SKIES WITH A SLOW RISE IN TEMPS
THROUGH MONDAY AS WARM ADVECTION COMMENCES. DESPITE THE
SUNSHINE...THICKNESSES SUPPORT HIGHS REMAINING IN THE UPPER 20S AND
LOWER 30S SUNDAY...WITH HIGHS MODERATING INTO THE MID AND UPPER 30S
FOR MONDAY AS THE HIGH SHIFTS EAST AND RETURN SOUTHERLY FLOW
DEVELOPS.
EXTENDED MODELS REMAIN LARGELY IN GOOD AGREEMENT ON THE ARRIVAL OF
AN UPPER LEVEL DISTURBANCE MONDAY NIGHT/TUESDAY WITH ONLY THE GGEM
LAGGING THE FEATURE DUE TO INCREASED PHASING ALOFT. HAVE LEANED
CLOSER TO ECMWF WHICH HAS REMAINED CONSISTENT OVER THE LAST FEW RUNS
IN LOWER LEVELS COOLING SUFFICIENTLY ENOUGH MONDAY NIGHT FOR PRECIP
TO FALL AS LIGHT SNOW. COULD SEE SOME RAIN MIX IN WITH THE SNOW OVER
FAR SOUTHERN PORTIONS OF THE FORECAST AREA...BUT UNCERTAINTY IN THAT
HAPPENING RIGHT NOW IS HIGH ENOUGH TO KEEP A MIX MENTION OUT OF THE
FORECAST UNTIL TUESDAY AS TEMPS WARM. WILL MAINTAIN CHANCE POPS
THROUGH THIS TIMEFRAME.
SOME TIMING DIFFERENCES DEVELOP FROM THIS POINT FORWARD AS OP GFS
AND ECMWF ARE HANDLING THE EJECTION OF ENERGY OUT OF THE DEVELOPING
PACIFIC COAST TROUGH IN DIFFERENT WAYS. GROWING CONFIDENCE IN HIGH
PRESSURE BRIEFLY REESTABLISHING OVER THE OHIO VALLEY TUESDAY NIGHT
AND WEDNESDAY BEHIND THE LEAD UPPER WAVE AND HAVE CUT ALLBLEND POPS
SUBSTANTIALLY AS A RESULT. THE ARRIVAL OF THE UPPER ENERGY FROM THE
WESTERN TROUGH WILL SPUR A SURFACE WAVE TRAVERSING THE OHIO VALLEY
LATE WEDNESDAY INTO THURSDAY. AT THIS POINT IN TIME...APPEARS LOW
LEVEL THICKNESSES AND SURFACE TEMPS WARM ENOUGH TO SUPPORT MAINLY
RAIN FOR MUCH OF THE FORECAST AREA. UNTIL EXTENDED GUIDANCE CAN COME
INTO ALIGNMENT WITH REGARDS TO TRACK AND TIMING OF THE LOW...WILL BE
DIFFICULT TO EMPLOY MUCH ADDITIONAL DETAIL. WILL CARRY CHANCE POPS
WEDNESDAY NIGHT AND THURSDAY WITH TEMPS LIKELY WARMING INTO THE 40S.
&&
.AVIATION /DISCUSSION FOR THE 090900Z TAF UPDATE/...
EXTREMELY PESKY STRATOCU DECK REMAINS SLOW IN ITS SOUTHWARD
DEPARTURE FROM THE REGION. NEWER RH PROGS OFF THE RUC SUGGESTING
CEILINGS MAY HANG A FEW HOURS LONGER THAN PREVIOUSLY THOUGHT AND
SATELLITE TRENDS WOULD TEND TO SUPPORT THIS IDEA. HAVE THEREFORE
BACKED OFF ON DEPARTURE OF STRATOCU AT KHUF AND KIND UNTIL 12Z AND
POSSIBLY NOT UNTIL 17-18Z AT KBMG. WILL HAVE TO MONITOR TRENDS OVER
THE NEXT FEW HORUS AT KHUF AND KIND AS ENTIRELY PLAUSIBLE THAT THE
STRATOCU TAKES UNTIL MID MORNING BEFORE SHIFTING SOUTH.
06Z DISCUSSION FOLLOWS.
STILL SEEING SOME MVFR CEILINGS AROUND 020 LINGERING IN THE
KIND/KBMG AREAS...BUT THE OVERALL TREND IS FOR THESE CEILINGS TO
DISSIPATE FROM THE NORTHWEST. WILL HOLD ONTO MVFR CEILINGS IN THE
KBMG AREA UNTIL ABOUT 090800Z.
OTHERWISE...BACK EDGE OF VFR CLOUD DECK 035-040 CONTINUES TO SLOWLY
SINK SOUTHEAST. DECK SHOULD CLEAR KIND/KHUF BEFORE SUNRISE...BUT
PROBABLY NOT UNTIL AFTER SUNRISE AT KBMG. THE LATENESS OF THE
CLEARING COUPLED WITH LOWER DEWPOINTS ADVECTING IN FROM THE WEST
SHOULD PREVENT ANY WIDESPREAD OR PROLONGED VISIBILITY RESTRICTIONS
DUE TO FOG.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...TDUD
NEAR TERM...TDUD
SHORT TERM...TDUD
LONG TERM....RYAN
AVIATION...JAS/RYAN
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
324 AM EST THU FEB 9 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
HIGH PRESSURE WILL MOVE INTO THE AREA BRINGING DRY WEATHER TO
CENTRAL INDIANA THROUGH THURSDAY. AN ARCTIC COLD FRONT WILL MOVE
THROUGH ON FRIDAY BRINGING COLDER THAN AVERAGE TEMPERATURES ALONG
WITH A CHANCE FOR SNOW. ANOTHER FRONT WILL ARRIVE BY MID-WEEK NEXT
WEEK.
&&
.NEAR TERM /OVERNIGHT/...
SATELLITE IMAGES INDICATE CLOUDS OVER CENTRAL INDIANA SLOWLY
CLEARING FROM NORTHWEST TO SOUTHEAST. RUC RH PROFILES SUGGEST
CLOUD SHOULD DEPART TO THE SOUTHEAST AS THE NIGHT
PROGRESSES. THUS MADE SOME MINOR TWEAKS TO SKY GRIDS TO INCREASE
CLEARING GRADIENT...PARTICULARLY ACROSS THE NORTHERN PARTS OF THE
FORECAST AREA.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY/...
FOCUS IS ON CHANCES FOR PRECIPITATION FRIDAY AND SATURDAY. FOR THE
MOST PART...MODELS ARE SIMILAR ENOUGH THAT A BLEND CAN BE USED.
HIGH PRESSURE WILL PROVIDE DRY CONDITIONS FOR THURSDAY AND
THURSDAY NIGHT UNDER MOSTLY CLEAR TO PARTLY CLOUDY SKIES.
GENERALLY STUCK WITH MAV MOS...ALTHOUGH WENT A BIT WARMER THAN MAV
MOS SOME AREAS THURSDAY NIGHT WITH AN INCREASE IN CLOUD COVER
EXPECTED.
THE COLD FRONT WILL MOVE INTO THE AREA ON FRIDAY INTO FRIDAY
NIGHT. ALTHOUGH IT WILL NOT HAVE A LOT OF MOISTURE WITH
IT...ARCTIC FRONTS TEND TO BE ABLE TO SQUEEZE OUT MORE THAN
EXPECTED. THUS RAISED MOS POPS FRIDAY AND FRIDAY NIGHT...BUT STUCK
TO NO HIGHER THAN THE CHANCE CATEGORY.
BASED ON EXPECTED BOUNDARY LAYER TEMPERATURES AHEAD OF THE
FRONT...WENT WITH A RAIN/SNOW MIX ACROSS THE SOUTH HALF OF THE
AREA BY FRIDAY AFTERNOON. FOR FRIDAY NIGHT WENT ALL SNOW AS COLDER
AIR MOVES IN.
SOME OF THE LAKE EFFECT SNOW SHOWERS THAT DEVELOP SATURDAY MAY
SNEAK INTO THE NORTHWEST FORECAST AREA...SO WENT SLIGHT CHANCE
POPS THERE. OTHERWISE IT LOOKS LIKE DRY BUT COLD CONDITIONS WILL
BE THE RULE SATURDAY.
WITH CLOUDS AROUND FRIDAY NIGHT...WENT WARMER THAN MAV MOS FOR
LOWS. STUCK WITH A BLEND FOR SATURDAY.
&&
.LONG TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
PERIOD BEGINS WITH A 1035-40MB SURFACE HIGH ACROSS THE NORTHERN
PLAINS AND THE FORECAST AREA ON SUBSIDENCE SIDE OF AN UPPER WAVE
ASSOCIATED WITH THE STRONG UPPER LOW JUST EAST OF THE HUDSON BAY IN
QUEBEC. FORTUNATELY OR UNFORTUNATELY...DEPENDING ON WHAT YOU
PREFER...THE BULK OF THE COLDEST AIR WILL BE NORTHEAST OF THE FORECAST
AREA CLOSER TO THE CENTER OF THE UPPER LOW. THE TWO MAIN WEATHER
FEATURES FOR THE EXTENDED TIMEFRAME APPEAR IN DAYS 6/7...AS A COUPLE
UPPER LEVEL WAVES EJECT FROM THE LOWER ROCKIES AND PUSH EAST TOWARD
THE OHIO RIVER VALLEY. MID/LONG RANGE MODEL SOLNS ARE IN FAIRLY GOOD
AGREEMENT WITH THE HANDLING OF THE INITIAL WAVE ON MONDAY NIGHT INTO
TUESDAY AND WITH COLD AIR ALREADY IN PLACE...SNOW IS EXPECTED IN
ALL BUT THE BOTTOM TWO TIER OF COUNTIES WHERE FORECAST SOUNDINGS
ILLUSTRATE A RAIN/SNOW MIX MAY OCCUR. UPPED POPS AREA-WIDE FOR
THIS INITIAL SYSTEM AS MODEL AGREEMENT AND CONSISTENCY HAS BOOST
CONFIDENCE IN ITS OCCURRENCE.
TIMING OF THE SECOND SHORTWAVE IS A LITTLE TRICKIER...AS THE ECMWF
AMPLIFIES UPPER RIDGING AHEAD OF THIS SECOND WAVE MORE THAN THE
GFS. THIS WILL ACT TO SLOW THE SYSTEM A GOOD FULL DAY LATER THAN
THE GFS. WITH MORE MOISTURE TO WORK WITH THAN THE INITIAL
SHORTWAVE...THE TRACK OF THE SURFACE LOW WILL BE IMPORTANT IN
DETERMINING PRECIP TYPE.
&&
.AVIATION /DISCUSSION FOR THE 090900Z TAF UPDATE/...
EXTREMELY PESKY STRATOCU DECK REMAINS SLOW IN ITS SOUTHWARD
DEPARTURE FROM THE REGION. NEWER RH PROGS OFF THE RUC SUGGESTING
CEILINGS MAY HANG A FEW HOURS LONGER THAN PREVIOUSLY THOUGHT AND
SATELLITE TRENDS WOULD TEND TO SUPPORT THIS IDEA. HAVE THEREFORE
BACKED OFF ON DEPARTURE OF STRATOCU AT KHUF AND KIND UNTIL 12Z AND
POSSIBLY NOT UNTIL 17-18Z AT KBMG. WILL HAVE TO MONITOR TRENDS OVER
THE NEXT FEW HORUS AT KHUF AND KIND AS ENTIRELY PLAUSIBLE THAT THE
STRATOCU TAKES UNTIL MID MORNING BEFORE SHIFTING SOUTH.
06Z DISCUSSION FOLLOWS.
STILL SEEING SOME MVFR CEILINGS AROUND 020 LINGERING IN THE
KIND/KBMG AREAS...BUT THE OVERALL TREND IS FOR THESE CEILINGS TO
DISSIPATE FROM THE NORTHWEST. WILL HOLD ONTO MVFR CEILINGS IN THE
KBMG AREA UNTIL ABOUT 090800Z.
OTHERWISE...BACK EDGE OF VFR CLOUD DECK 035-040 CONTINUES TO SLOWLY
SINK SOUTHEAST. DECK SHOULD CLEAR KIND/KHUF BEFORE SUNRISE...BUT
PROBABLY NOT UNTIL AFTER SUNRISE AT KBMG. THE LATENESS OF THE
CLEARING COUPLED WITH LOWER DEWPOINTS ADVECTING IN FROM THE WEST
SHOULD PREVENT ANY WIDESPREAD OR PROLONGED VISIBILITY RESTRICTIONS
DUE TO FOG.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...50
NEAR TERM...PUMA
SHORT TERM...50
LONG TERM....MRD
AVIATION...JAS/RYAN
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1135 PM EST WED FEB 8 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
HIGH PRESSURE WILL MOVE INTO THE AREA BRINGING DRY WEATHER TO
CENTRAL INDIANA THROUGH THURSDAY. AN ARCTIC COLD FRONT WILL MOVE
THROUGH ON FRIDAY BRINGING COLDER THAN AVERAGE TEMPERATURES ALONG
WITH A CHANCE FOR SNOW. ANOTHER FRONT WILL ARRIVE BY MID-WEEK NEXT
WEEK.
&&
.NEAR TERM /OVERNIGHT/...
SATELLITE IMAGES INDICATE CLOUDS OVER CENTRAL INDIANA SLOWLY
CLEARING FROM NORTHWEST TO SOUTHEAST. RUC RH PROFILES SUGGEST
CLOUD SHOULD DEPART TO THE SOUTHEAST AS THE NIGHT
PROGRESSES. THUS MADE SOME MINOR TWEAKS TO SKY GRIDS TO INCREASE
CLEARING GRADIENT...PARTICULARLY ACROSS THE NORTHERN PARTS OF THE
FORECAST AREA.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY/...
FOCUS IS ON CHANCES FOR PRECIPITATION FRIDAY AND SATURDAY. FOR THE
MOST PART...MODELS ARE SIMILAR ENOUGH THAT A BLEND CAN BE USED.
HIGH PRESSURE WILL PROVIDE DRY CONDITIONS FOR THURSDAY AND
THURSDAY NIGHT UNDER MOSTLY CLEAR TO PARTLY CLOUDY SKIES.
GENERALLY STUCK WITH MAV MOS...ALTHOUGH WENT A BIT WARMER THAN MAV
MOS SOME AREAS THURSDAY NIGHT WITH AN INCREASE IN CLOUD COVER
EXPECTED.
THE COLD FRONT WILL MOVE INTO THE AREA ON FRIDAY INTO FRIDAY
NIGHT. ALTHOUGH IT WILL NOT HAVE A LOT OF MOISTURE WITH
IT...ARCTIC FRONTS TEND TO BE ABLE TO SQUEEZE OUT MORE THAN
EXPECTED. THUS RAISED MOS POPS FRIDAY AND FRIDAY NIGHT...BUT STUCK
TO NO HIGHER THAN THE CHANCE CATEGORY.
BASED ON EXPECTED BOUNDARY LAYER TEMPERATURES AHEAD OF THE
FRONT...WENT WITH A RAIN/SNOW MIX ACROSS THE SOUTH HALF OF THE
AREA BY FRIDAY AFTERNOON. FOR FRIDAY NIGHT WENT ALL SNOW AS COLDER
AIR MOVES IN.
SOME OF THE LAKE EFFECT SNOW SHOWERS THAT DEVELOP SATURDAY MAY
SNEAK INTO THE NORTHWEST FORECAST AREA...SO WENT SLIGHT CHANCE
POPS THERE. OTHERWISE IT LOOKS LIKE DRY BUT COLD CONDITIONS WILL
BE THE RULE SATURDAY.
WITH CLOUDS AROUND FRIDAY NIGHT...WENT WARMER THAN MAV MOS FOR
LOWS. STUCK WITH A BLEND FOR SATURDAY.
&&
.LONG TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
PERIOD BEGINS WITH A 1035-40MB SURFACE HIGH ACROSS THE NORTHERN
PLAINS AND THE FORECAST AREA ON SUBSIDENCE SIDE OF AN UPPER WAVE
ASSOCIATED WITH THE STRONG UPPER LOW JUST EAST OF THE HUDSON BAY IN
QUEBEC. FORTUNATELY OR UNFORTUNATELY...DEPENDING ON WHAT YOU
PREFER...THE BULK OF THE COLDEST AIR WILL BE NORTHEAST OF THE FORECAST
AREA CLOSER TO THE CENTER OF THE UPPER LOW. THE TWO MAIN WEATHER
FEATURES FOR THE EXTENDED TIMEFRAME APPEAR IN DAYS 6/7...AS A COUPLE
UPPER LEVEL WAVES EJECT FROM THE LOWER ROCKIES AND PUSH EAST TOWARD
THE OHIO RIVER VALLEY. MID/LONG RANGE MODEL SOLNS ARE IN FAIRLY GOOD
AGREEMENT WITH THE HANDLING OF THE INITIAL WAVE ON MONDAY NIGHT INTO
TUESDAY AND WITH COLD AIR ALREADY IN PLACE...SNOW IS EXPECTED IN
ALL BUT THE BOTTOM TWO TIER OF COUNTIES WHERE FORECAST SOUNDINGS
ILLUSTRATE A RAIN/SNOW MIX MAY OCCUR. UPPED POPS AREA-WIDE FOR
THIS INITIAL SYSTEM AS MODEL AGREEMENT AND CONSISTENCY HAS BOOST
CONFIDENCE IN ITS OCCURRENCE.
TIMING OF THE SECOND SHORTWAVE IS A LITTLE TRICKIER...AS THE ECMWF
AMPLIFIES UPPER RIDGING AHEAD OF THIS SECOND WAVE MORE THAN THE
GFS. THIS WILL ACT TO SLOW THE SYSTEM A GOOD FULL DAY LATER THAN
THE GFS. WITH MORE MOISTURE TO WORK WITH THAN THE INITIAL
SHORTWAVE...THE TRACK OF THE SURFACE LOW WILL BE IMPORTANT IN
DETERMINING PRECIP TYPE.
&&
.AVIATION /DISCUSSION FOR THE 090600Z TAFS/...
STILL SEEING SOME MVFR CEILINGS AROUND 020 LINGERING IN THE
KIND/KBMG AREAS...BUT THE OVERALL TREND IS FOR THESE CEILINGS TO
DISSIPATE FROM THE NORTHWEST. WILL HOLD ONTO MVFR CEILINGS IN THE
KBMG AREA UNTIL ABOUT 090800Z.
OTHERWISE...BACK EDGE OF VFR CLOUD DECK 035-040 CONTINUES TO SLOWLY
SINK SOUTHEAST. DECK SHOULD CLEAR KIND/KHUF BEFORE SUNRISE...BUT
PROBABLY NOT UNTIL AFTER SUNRISE AT KBMG. THE LATENESS OF THE
CLEARING COUPLED WITH LOWER DEWPOINTS ADVECTING IN FROM THE WEST
SHOULD PREVENT ANY WIDESPREAD OR PROLONGED VISIBILITY RESTRICTIONS
DUE TO FOG.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...50
NEAR TERM...PUMA
SHORT TERM...50
LONG TERM....MRD
AVIATION...JAS
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
539 PM CST FRI FEB 10 2012
.AVIATION...
CONVECTIVE SHSN AND --SN WILL CONTINUE TO DIMINISH THROUGH EARLY EVE
WITH SUNSET. STRATUS WITH MAINLY VFR CIGS WILL LINGER... BUT
CLEARING ALREADY PROGRESSING SWD THROUGH WI AND IS EXPECTED TO
OVERSPREAD THE TERMINALS FROM N TO S TNGT. N/NW WINDS WILL REMAIN
GUSTY AT 10-20 KTS... AND SHOULD DIMINISH TO AROUND 10 KTS AND LOSE
GUSTINESS WHEN SKIES CLEAR. BY MID AM SAT WITH MIXING AND LINGERING
PRESSURE GRADIENT WINDS ARE EXPECTED TO BECOME GUSTY ONCE AGAIN AT
10-20 KTS.
&&
.PREV DISCUSSION... /ISSUED 305 PM CST FRI FEB 10 2012/
SYNOPSIS...
12Z UA ANALYSIS HAS A COLD FRONT FROM THE MACKINAC STRAITS INTO
NORTHERN KANSAS WITH TROFS FROM THE MID ATLANTIC BACK INTO THE
PLAINS. SATELLITE AND RADAR TRENDS THROUGH MID AFTERNOON SHOWS AREAS
OF LIGHT SNOW AND SNOW SHOWERS ACROSS THE WESTERN GREAT LAKES WITH
CLEARING SKIES IN MINNESOTA.
18Z SFC ANALYSIS HAS A LOW JUST EAST OF KMKG AND ANOTHER JUST
NORTHEAST OF KORD. THE ARCTIC FRONT RAN FROM THE SECOND LOW
SOUTHWEST INTO NORTHERN TEXAS. DEW POINTS WERE IN THE 20S AND 30S
AHEAD AND IMMEDIATELY BEHIND THE FRONT WITH SINGLE DIGITS ABOVE AND
BELOW ZERO ACROSS THE NORTHERN PLAINS.
SHORT TERM...TONIGHT AND SATURDAY...
RUC TRENDS USING THE 900-950MB AND 0.5-1.0KM RH LAYERS ARE DOING A
REASONABLY GOOD JOB OF DEPICTING THE CURRENT CLOUD COVER ACROSS THE
AREA. SNOW SHOWERS/FLURRIES WILL CONTINUE THROUGH THE AFTERNOON WITH
MOST SNOW SHOWERS DISSIPATING WITH SUNSET. STRONG CYCLONIC FLOW AND
VORT MAXES ROTATING THROUGH THE AREA SHOULD PROLONG THE FLURRIES
INTO THE EARLY EVENING OVER ROUGHLY THE EASTERN HALF OF THE CWFA.
GENERAL ACCUMULATIONS SHOULD RANGE FROM A TRACE TO A DUSTING.
A FEW HOURS AGO THE RUC WAS INDICATING CLEARING WOULD OCCUR FROM THE
NORTHWEST AFTER MID EVENING AND THEN TAKE MOST OF THE NIGHT TO CLEAR
OUT EAST OF THE MISSISSIPPI. HOWEVER...A NEW CLEAR AREA HAS
DEVELOPED IN AN AREA OF SUBSIDENCE ACROSS NORTHERN WISCONSIN. RUC
TRENDS USING THE 900-950MB AND 0.5-1.0KM RH LAYERS ARE NOW
SUGGESTING THE CWFA MAY SEE CLEARING STARTING FROM THE NORTHWEST AND
WEST AFTER MID-EVENING AND ALSO FROM THE NORTHEAST. IF THIS DOES
OCCUR THEN ROUGHLY THE SOUTHEAST QUADRANT OF THE CWFA WOULD BE THE
LAST TO CLEAR OUT AFTER MIDNIGHT.
TEMPERATURES WILL BE INTERESTING. AREAS THAT CLEAR OUT SOONER WILL
DROP QUICKLY DUE TO THE CAA THAT WILL CONTINUE OVERNIGHT. THE FACT
THAT WINDS WILL NOT DECOUPLE FROM THE BOUNDARY LAYER WILL BE WHAT
KEEPS LOWS ABOVE ZERO. FAVORED COLD AREAS IN THE WAPSI AND SAUK
VALLEYS MAY APPROACH ZERO IN SPITE OF THE WINDS. THE WIND AND
TEMPERATURES WILL DROP WIND CHILLS WELL BELOW ZERO BUT ARE EXPECTED
TO REMAIN JUST ABOVE ADVISORY CRITERIA.
SATURDAY WILL BE A COLD BRISK DAY. ARCTIC HIGH PRESSURE BUILDING
INTO THE AREA WILL RESULT IN SUNNY SKIES BUT WIND CHILLS ARE
EXPECTED TO REMAIN BELOW ZERO FOR MUCH OF THE MORNING. MAX
TEMPERATURES WILL STRUGGLE TO GET INTO THE UPPER TEENS AND LOWER 20S
BY MID AFTERNOON.
.08..
LONG TERM...SATURDAY NIGHT THROUGH NEXT FRIDAY...
A HIGH PRESSURE RIDGE CENTERED OVER WESTERN IOWA SATURDAY EVENING
WILL MOVE EAST THROUGH THE MID MISSISSIPPI RIVER VALLEY BY MONDAY
MORNING. TEMPERATURES WILL BE THE MAIN CONCERN SATURDAY NIGHT AND
SUNDAY WITH THE RIDGE AXIS JUST WEST OF THE CWFA. THERE SHOULD BE
ENOUGH OF A PRESSURE GRADIENT TO KEEP WINDS FROM DECOUPLING. THE
WIND ALONG ALONG WITH BARE GROUND SHOULD KEEP MIN TEMPS SATURDAY
NIGHT ABOVE ZERO. ALTHOUGH A SMALL PART OF THE SOUTHWEST CWFA COULD
SLIP BELOW ZERO SINCE VISIBLE SATELLITE IMAGERY SHOWS SOME SNOW
COVER NOSING INTO THE AREA. TEMPS ARE EXPECTED TO REBOUND INTO THE
20S FOR SUNDAY.
PRECIPITATION CHANCES ENTER THE PICTURE SUNDAY NIGHT THROUGH TUESDAY
AS RETURN FLOW SETS UP BEHIND THE RETREATING LOW LEVEL RIDGE AND A
SHORT WAVE MOVES FROM THE NORTHERN PLAINS THROUGH THE MID AND UPPER
MISSISSIPPI VALLEY. THE GFS/NAM ARE THE MOST BULLISH ON PRECIP
DURING THIS PERIOD...GENERATING ABOUT 2 TO 3 TENTHS OF INCH WATER
EQUIVALENT WHILE THE ECMWF PRODUCES 1 TO 2 TENTHS. TEMPERATURES
WILL BE COLD ENOUGH THROUGH THE EVENT FOR ALL SNOW. KEPT AMOUNTS
IN THE 1 TO 3 INCH RANGE WITH THE HIGHEST AMOUNTS WEST AND NORTH.
IF THE GFS VERIFIES THEN THE 3 INCH AMOUNTS SHOULD BE REALIZED WHILE
THE ECMWF WOULD SUPPORT AMOUNTS CLOSER TO AN INCH. THE MEASURABLE
SNOW SHOULD END MONDAY EVENING WITH SOME FLURRIES LINGERING INTO
TUESDAY...SPECIALLY EAST OF THE MISSISSIPPI RIVER.
MODELS CONTINUE TO SHOW A SPLIT FLOW REGIME THROUGH THE REST OF THE
FORECAST PERIOD WITH TEMPERATURES RETURNING TO NEAR OR JUST ABOVE
NORMAL. MOST OF THE SOLUTIONS MOVE A NORTHERN STREAM TROF THROUGH
THE REGION THURSDAY OR FRIDAY BUT KEEP THE SYSTEM UN-PHASED AND
MOISTURE STARVED. THE LONE EXCEPTION IS THE 12Z ECMWF WHICH PHASES
THE TROF WITH THE SOUTHERN STREAM...RESULTING IN A MODERATE PRECIP
EVENT FOR THE REGION. AT THIS POINT THERE IS LOW CONFIDENCE IN THE
EXTENDED PROGS SO KEPT SOME SLIGHT CHANCE POPS IN FOR ALL OR PART OF
THE AREA WEDNESDAY THROUGH FRIDAY. ..DLF..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
305 PM CST THU FEB 9 2012
.SYNOPSIS...
12Z UA ANALYSIS HAS SEVERAL SHORTWAVE TROFS FROM THE GREAT LAKES
BACK INTO THE PLAINS. AN 850MB COLD FRONT RAN FROM CANADIAN UA SITE
CYEG IN ALBERTA PROVINCE TO THE SOUTH EDGE OF JAMES BAY. SATELLITE
TRENDS THROUGH MID AFTERNOON SHOW THE LOW CLOUDS MOVING EAST ACROSS
THE AREA WITH CLEARING ACROSS SOUTHERN MINNESOTA AND WISCONSIN. THE
LOW POST FRONTAL CLOUDS OF THE ARCTIC FRONT WERE ACROSS NORTH DAKOTA
AND NORTHERN MINNESOTA.
18Z SFC ANALYSIS HAD A RIDGE RUNNING FROM THE LOWER MISSISSIPPI
VALLEY INTO THE OHIO VALLEY. THE ARCTIC FRONT RAN FROM EASTERN
MONTANA INTO NORTHWEST MINNESOTA. DEW POINTS ACROSS THE MIDWEST WERE
GENERALLY IN THE TEENS AND 20S WITH 30S IN THE SOUTHERN PLAINS AND
EASTERN KANSAS.
&&
.SHORT TERM...TONIGHT AND FRIDAY...
THE SHALLOW NATURE OF THE CLOUDS...ROUGHLY 1-2KFT...IS ONE OF MANY
REASONS WHY THE MODELS ARE DOING AN EXTREMELY POOR JOB OF DEPICTING
THEM AND HANDLING THEIR OVERALL MOVEMENT. THESE CLOUDS PLAY
SIGNIFICANTLY INTO SENSIBLE WX TRENDS TONIGHT BEFORE THE ARCTIC
FRONT ARRIVES.
THE RUC AND WRF HAVE A VAGUE IDEA ABOUT THE CLOUDS AND EITHER THE
0.5-1KM LAYER OR 0.5KM LAYER IS AT LEAST HINTING AT THE CLOUDS.
USING THIS ALONG WITH EXTRAPOLATION FROM CURRENT SATELLITE TRENDS
RESULTS IN CLOUDY SKIES FOR THE REMAINDER OF THE AFTERNOON AND INTO
THE EVENING HOURS. BASED ON THE CURRENT CLEAR AREA TO THE NORTH AND
WHAT THE MODELS ARE SUGGESTING...THE CLOUDS SHOULD PARTIALLY BREAK
UP ACROSS THE NORTHERN THIRD OF THE CWFA LATE THIS EVENING. WHAT
PARTIAL CLEARING THAT DEVELOPS WILL BE FORCED SOUTH AFTER MIDNIGHT
AS THE ARCTIC FRONT STARTS MOVING INTO THE CWFA.
BECAUSE OF THE CLOUDS...TEMPERATURES WILL BE WARMER THAN LAST NIGHT.
ANY AREAS THAT DO SEE PARTIAL OR A TOTAL CLEARING SHOULD DROP AND
THEN REBOUND AS THE POST FRONTAL CLOUDS OF THE ARCTIC FRONT ARRIVE.
THE CAA BEHIND THE ARCTIC FRONT IS IMPRESSIVE. LOW TEMPERATURES
TONIGHT WILL LIKELY OCCUR 7-8 AM FRIDAY MORNING.
ON FRIDAY...THE ARCTIC FRONT WILL CLEAR THE CWFA BY MID TO LATE
MORNING WITH POST FRONTAL STRATUS CLOUDS FOLLOWING BEHIND IT. THE
COMBINATION OF CAA...STRONG CYCLONIC FLOW ALOFT...A STRONG VORT
MAX...STEEPENING LOW LEVEL LAPSE RATES...AND THE STRONGER FEBRUARY
SUN ALL POINT TO SNOW SHOWERS DEVELOPING FROM LATE MORNING THROUGH
THE AFTERNOON. FCST SOUNDINGS DO SHOW SOME SMALL CAPE DEVELOPING AS
LAPSE RATES STEEPEN. PRIOR TO THE SNOW SHOWERS DEVELOPING THERE ARE
REASONABLY LOW CONDENSATION PRESSURE DEFICITS WITH SOME FORCING AND
F VECTOR CONVERGENCE. THUS FLURRIES MAY BE POSSIBLE WITH THE POST
FRONTAL STRATUS BEFORE THE SNOW SHOWERS DEVELOP.
SNOW AMOUNTS WITH THE SNOW SHOWERS WILL BE VARIED. AMOUNTS COULD
RANGE FROM ONLY A TRACE TO AROUND ONE HALF INCH IN THE STRONGER
SHOWERS.
WINDS WILL BE QUITE BRISK ON FRIDAY AND MAY BE LOCALLY STRONGER
AROUND SNOW SHOWERS.
MAX TEMPERATURES FRIDAY WILL LIKELY OCCUR 9-11 AM WITH TEMPERATURES
EITHER STEADY OR SLOWLY FALLING DURING THE AFTERNOON. ..08..
.LONG TERM...FRIDAY NIGHT THROUGH NEXT THURSDAY...
SEASONALLY COLD...A LIGHT SNOW EVENT MONDAY WITH A MODEST WARMING
TREND INTO MIDDLE OF NEXT WEEK.
OVERALL...LARGE SCALE FEATURES REASONABLE BUT LOW LEVEL BL PROBLEMS
CONTINUE WITH MOST SOLUTIONS T/TD PROFILES LOWEST 2K AGL STILL OFF.
MAIN CONTRIBUTOR IS OUR UNSEASONABLY LOW AMOUNTS OF SNOW NOT HANDLED
BY PHYSICS PACKAGES. THIS IS RESULTING IN BL FORECASTS...ESPECIALLY
AMERICAN SOLUTIONS EITHER TOO MOIST OR TOO DRY. INITIALIZATION AND
VERIFICATION AGAIN SUGGESTS A HIGHER WEIGHT BE GIVEN TO COLDEST
GUIDANCE FOR MIN TEMPERATURES WITH ARCTIC AIR IF NOT A FEW DEGREES
COLDER. FOR HIGHS...ON THE WARM END FOR MAX TEMPS INTO MONDAY.
TEXTBOOK WIDESPREAD LIGHT SNOW EVENT MONDAY WITH LOCAL TOOLS
SUGGESTING .5 TO 1.5 INCHES OF SNOW MOST LOCATIONS AT THIS TIME. NEXT
24 HOURS...FINER DETAILS MAY SUGGEST A LEAD VORT MAX...THEN SOME
ISOLATED 2 TO 3 INCHES NOT OUT OF THE QUESTION...THIS SHOULD BE KNOWN
THIS TIME TOMORROW.
FRIDAY NIGHT...CLEARING WITH STRONG CAA WITH NW WINDS 10-20+ MPH IN
THE EVENING DECREASING TO 5-10 MPH OVERNIGHT. LOCAL TECHNIQUES
SUPPORT 0-5F ABOVE NW 1/2 AND 5-10F ABOVE SE 1/2. WHEN ADJUSTING FOR
BL PROBLEMS...POSSIBLE MINS MAY STILL BE 2-5 DEGREES TOO MILD FOR
MANY IF NOT MOST LOCATIONS FOR LATER SIFTS TO REASSESS.
SATURDAY AND SUNDAY...FAIR AND COLD WITH HIGHS UPPER TEENS TO MID 20S
BOTH DAYS AND LOWS SUNDAY AM IN THE SINGLE DIGITS WITH SOME BELOW
ZERO READINGS AGAIN POSSIBLE NW SECTIONS. SUNDAY NIGHT...INCREASING
CLOUDS LATE WITH MINS IN THE TEENS WITH SLOWLY RISING TEMPERATURES
POSSIBLE AFTER MIDNIGHT.
MONDAY... UPPED POPS TO LOW END LIKELY TO HIGH END CHANCE WITH AREAS
OF LIGHT SNOW TO OVERSPREAD AREA THROUGH MONDAY NIGHT. LOCAL TOOLS
SUGGEST MOSTLY .5-1.5 INCHES ATTM WITH RISK OF SOME ISOLATED HIGHER
AMOUNTS OF 2-3 INCHES POSSIBLE IF LEAD VORT MAX IS STRONGER. BL
ISSUES MAKE THIS A CHALLENGE THAT LATER SHIFTS WILL NEED TO STAY ON
TOP OF. HIGHS NEAR FREEZING WITH SOUTH WINDS LIMITING ACCUMULATIONS
ON THE MOST TRAVELED ROADS. MONDAY...LIGHT SNOW TO DIMINISH TO
FLURRIES OR END BY LATE OVERNIGHT HOURS. WITH MINOR ACCUMULATIONS IN
THE FAR EAST UNTIL MIDNIGHT. LOWS WITH CLEARING IN THE NW SECTIONS
MAY NEED TO BE TRIMMED FURTHER BY 2 TO 5 DEGREES.
TUESDAY THROUGH THURSDAY...DRY TO MOSTLY DRY WITH LOW CHANCE POPS ON
WEDNESDAY AND THURSDAY...MOSTLY LOWER SOUTH SECTIONS. MAIN FORCING
IS SUGGESTED TO PASS TO THE SOUTH SO ANY AMOUNTS TO BE LIGHT IF NOT
DRY. LATER SHIFTS MAY BE ABLE TO REMOVE POPS MANY LOCATIONS THE NEXT
FEW DAYS. TEMPERATURES OVERALL TO TREND NEAR TO SLIGHTLY ABOVE
NORMAL. ..NICHOLS..
&&
.AVIATION...
CONTINUED HEATING HAS ALLOWED CIGS TO BECOME VFR EXCEPT KDBQ WHICH
REMAINS MVFR. NO MODEL IS HANDLING THE LOW CLOUDS BUT PARTIAL
CLEARING SHOULD OCCUR 02Z-09Z/10 THAT SHOULD ALLOW ALL TAF SITES TO
BECOME VFR. POST FRONTAL MVFR CIGS BEHIND THE ARCTIC FRONT WILL MOVE
IN FROM THE NORTH 10Z-16Z/10 WITH FLURRIES POSSIBLE. SHSN ARE
EXPECTED TO DVLP AFT 15Z/10 AS THE ATMOSPHERE BECOMES UNSTABLE.
..08..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
08/NICHOLS
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1130 AM CST THU FEB 9 2012
.AVIATION...
DAYTIME HEATING IS ALLOWING THE CLOUD BASES TO SLOWLY RISE. MVFR
CONDITIONS ARE AT KCID AND WILL BE AT KDBQ SHORTLY. KMLI/KBRL WILL
START OUT WITH VFR CIGS BUT KMLI MAY GO TO VFR AROUND SUNSET.
BASED ON EXTRAPOLATION AND SOME INPUTS FROM THE MODELS...VFR
CONDITIONS SHOULD AGAIN DVLP 02Z/10 TO 09Z/10 AT ALL TAF SITES.
ARCTIC FRONTAL PASSAGE TO OCCUR 10Z/10 TO 15Z/10 WITH WINDS
INCREASING AFT 14Z/10. POST FRONTAL STRATUS WILL BRING MVFR CIGS
BACK INTO EACH TAF SITE 12Z/10 TO 18Z/10.
..08..
&&
.PREV DISCUSSION... /ISSUED 1024 AM CST THU FEB 9 2012/
UPDATE...
THE LOW CLOUDS CONTINUE TO ADVECT INTO THE CWFA AND ARE EITHER AT
OR APPROACHING THE MISSISSIPPI RIVER. ONCE AGAIN NO MODEL IS
HANDLING THESE CLOUDS. THE 12Z WRF HAS A VAGUE IDEA AND THE RUC
TRENDS ALSO HAVE A VAGUE IDEA. PER THESE MODELS CLOUDS SHOULD BE
AROUND FOR THE REMAINDER OF THE AFTERNOON AND INTO THE EVENING
HOURS. THERE ARE QUESTIONS AS TO HOW MUCH CLEARING WILL OCCUR
TONIGHT AHEAD OF THE APPROACHING ARCTIC FRONT.
IF CURRENT CLOUD TRENDS HOLD...THE HWY 20 CORRIDOR MAY SEE
SUNSHINE AGAIN DURING THE AFTERNOON HOURS. HOWEVER...THE RUC IS
SUGGESTING THAT LOW LEVEL LAPSE RATES WILL BECOME QUITE STEEP
DURING THE AFTERNOON WHICH MAY PROMOTE CLOUD DEVELOPMENT IN THE
CURRENT CLEAR AREA OF NORTH CENTRAL IOWA. ADDITIONALLY...THE RUC
IS INDICATING WEAK F VECTOR CONVERGENCE WITH A SMALL DROP IN
CONDENSATION PRESSURE DEFICITS WITH NEUTRAL OR VERY WEAK FORCING.
IF LAPSE RATES DO STEEPEN AS SUGGESTED...SOME FLURRIES MAY NOT BE
OUT OF THE QUESTION THIS AFTERNOON.
MAX TEMPERATURES HAVE BE LOWERED A FEW DEGREES TO REFLECT THE
SLIGHTLY QUICKER ARRIVAL OF THE CLOUDS. AN UPDATE TO THE FCST
SHOULD BE AVAILABLE AROUND 1030 AM.
.08..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1024 AM CST THU FEB 9 2012
.UPDATE...
THE LOW CLOUDS CONTINUE TO ADVECT INTO THE CWFA AND ARE EITHER AT
OR APPROACHING THE MISSISSIPPI RIVER. ONCE AGAIN NO MODEL IS
HANDLING THESE CLOUDS. THE 12Z WRF HAS A VAGUE IDEA AND THE RUC
TRENDS ALSO HAVE A VAGUE IDEA. PER THESE MODELS CLOUDS SHOULD BE
AROUND FOR THE REMAINDER OF THE AFTERNOON AND INTO THE EVENING
HOURS. THERE ARE QUESTIONS AS TO HOW MUCH CLEARING WILL OCCUR
TONIGHT AHEAD OF THE APPROACHING ARCTIC FRONT.
IF CURRENT CLOUD TRENDS HOLD...THE HWY 20 CORRIDOR MAY SEE
SUNSHINE AGAIN DURING THE AFTERNOON HOURS. HOWEVER...THE RUC IS
SUGGESTING THAT LOW LEVEL LAPSE RATES WILL BECOME QUITE STEEP
DURING THE AFTERNOON WHICH MAY PROMOTE CLOUD DEVELOPMENT IN THE
CURRENT CLEAR AREA OF NORTH CENTRAL IOWA. ADDITIONALLY...THE RUC
IS INDICATING WEAK F VECTOR CONVERGENCE WITH A SMALL DROP IN
CONDENSATION PRESSURE DEFICITS WITH NEUTRAL OR VERY WEAK FORCING.
IF LAPSE RATES DO STEEPEN AS SUGGESTED...SOME FLURRIES MAY NOT BE
OUT OF THE QUESTION THIS AFTERNOON.
MAX TEMPERATURES HAVE BE LOWERED A FEW DEGREES TO REFLECT THE
SLIGHTLY QUICKER ARRIVAL OF THE CLOUDS. AN UPDATE TO THE FCST
SHOULD BE AVAILABLE AROUND 1030 AM.
..08..
&&
.AVIATION...
MVFR CIGS CONTINUE TO MOVE EASTWARD ACROSS IOWA AND AHEAD OF THE
CURRENT TAFS. TAFS HAVE BEEN UPDATED TO REFLECT AN EARLIER
ARRIVAL TIME. CIGS MAY INITIALLY BE VFR BUT SHOULD QUICKLY DROP
INTO THE MVFR RANGE.
..08..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1149 PM CST WED FEB 8 2012
.AVIATION...
SFC-925 MB RIDGE AXIS WILL SLIDE ACROSS REGION OVRNGT. SKIES WILL
REMAIN CLEAR WITH LIGHT WINDS 3-6 KTS BACKING TO SW THROUGH 12Z.
PATCHY FOG POSSIBLE FOR A FEW HRS TOWARD DAYBREAK WITH VSBYS
GENERALLY 3-6SM. ATTN THEN SHIFTS TO LARGE AREA OF STRATUS
CURRENTLY MOVING EWD THROUGH NE AND SW IA ATTIM. EXPECT THE
STRATUS TO CONTINUE MOVING EWD INTO MID AM THU AS SFC-925 MB
RIDGE DEPARTS AND WINDS BECOME WESTERLY AT AROUND 15 KTS JUST
ABOVE SFC. 00Z KOAX RAOB SHOWS MOISTURE VERY SHALLOW (ROUGHLY 100
FT THICK CENTERED AROUND AND JUST BELOW 890 MB). CHALLENGE
BECOMES TIMING OF STRATUS INTO THE TERMINALS. SEVERAL FACTORS OR
ELEMENTS MAKE THIS DIFFICULT WITH 1) STRENGTHENING FEB SOLAR
INSOLATION... THAT MAY AID IN SLOWING EWD PROGRESSION... 2)
INCREASED MIXING WITH W/SW WINDS INCREASING 10-15 KTS WITH SOME
GUSTS... WITH POTENTIAL TAP DRY AIR ABOVE THE STRATUS TO ALSO
PROMOTE EROSION. THE SLOWING ALSO DEPICTED IN MOST RECENT RUNS OF
HRRR TOTAL CLOUD COVER PRODUCT... THUS WITH 06Z TAFS HAVE
FOLLOWED SUIT AND PUSHED BACK ARRIVAL OF STRATUS WITH MVFR CIGS
UNTIL AFTN TO EARLY EVE.
&&
.PREV DISCUSSION... /ISSUED 305 PM CST WED FEB 8 2012/
SYNOPSIS...
12Z UA ANALYSIS HAS A RIDGE RUNNING FROM THE GULF COAST INTO
EASTERN MONTANA. ARCTIC AIR WAS OVER NORTHERN CANADA WITH THE
SOUTHERN EXTENT DOWN TO JAMES BAY. SATELLITE TRENDS THROUGH MID
AFTERNOON HAD STRATUS TRAPPED UNDER AN INVERSION FROM THE PLAINS
INTO CENTRAL ILLINOIS AND SOUTHEAST IOWA. THE 18Z SFC ANALYSIS HAD
THE RIDGE FROM THE DAKOTAS INTO TEXAS. A WEAK TROF RAN FROM THE
NORTHERN GREAT LAKES INTO WESTERN WISCONSIN. DEW POINTS WERE
GENERALLY IN THE TEENS AND 20S ACROSS MUCH OF THE MIDWEST WITH 30S
IN THE SOUTHERN PLAINS AND OHIO VALLEY.
SHORT TERM...TONIGHT AND THURSDAY...
THE SHALLOW LAYER OF STRATUS CLOUDS BELOW THE TRAPPING INVERSION IS
NOT BEING HANDLED AT ALL BY THE MODELS. DIURNAL HEATING FROM THE SUN
HAS STRENGTHENED THE INVERSION ABOVE THE CLOUDS CAUSING THE OVERALL
CLEARING TREND TO SLOW.
THE 950MB RH LEVEL ON THE RUC HAS DONE REASONABLY WELL IN DEPICTING
WHERE THE CLOUDS CURRENTLY ARE. USING THE RUC 950MB RH TRENDS
COMBINED WITH EXTRAPOLATION OF SATELLITE INDICATES THAT THE CLOUDS
WILL REMAIN ACROSS ROUGHLY THE SOUTHERN 40 PERCENT OF THE CWFA FOR
THE REMAINDER OF THE AFTERNOON. CLEARING IN THE SOUTH THIRD OF THE
CWFA WILL BE SLOW DURING THE EVENING BUT CLEAR SKIES SHOULD BE SEEN
ACROSS NEARLY ALL THE CWFA BY MIDNIGHT.
AFTER MIDNIGHT ANOTHER UPPER LEVEL DISTURBANCE APPROACHES. THIS
DISTURBANCE SHOULD JUST PASS THROUGH WITH NO NOTICEABLE AFFECTS.
HOWEVER...IF THE LOW CLOUDS ARE STILL IN PLACE ACROSS THE SOUTH
THIRD OF THE CWFA THEN ISOLATED FLURRIES WOULD BE POSSIBLE. FOR NOW
IT APPEARS THAT THE LOW CLOUDS SHOULD EXIT THE CWFA AROUND OR
SHORTLY AFTER MIDNIGHT. ASSUMING CLOUDS CLEAR TONIGHT...TEMPERATURES
SHOULD BE QUITE CHILLY.
THE CLEAR SKIES ON THURSDAY WILL GIVE WAY TO MORE CLOUDS THROUGH THE
DAY. THE 950MB RH FIELD FROM THE WRF...ALTHOUGH NOT AS GOOD THE
RUC...HAS A STRONG SIGNAL INDICATING THE LOW CLOUDS IN NEBRASKA/
KANSAS WILL ADVECT BACK INTO THE CWFA DURING THE MORNING HOURS. CLOUD
COVER FOR THURSDAY HAS BEEN INCREASED BUT IT IS LIKELY TOO LOW. THERE
IS SOME WEAK F VECTOR CONVERGENCE ACROSS THE AREA WHICH COULD PROMOTE
THE DEVELOPMENT OF FLURRIES. HOWEVER...FORCING IS WEAK TO NON-
EXISTENT SO THE CHANCES OF FLURRIES SHOULD BE VERY LOW. THE ARRIVAL
OF CLOUDS ON THURSDAY SHOULD AID IN SUPPRESSING TEMPERATURES.
08..
LONG TERM...THURSDAY NIGHT THROUGH NEXT WEDNESDAY...
THURSDAY NIGHT AND FRIDAY...DIGGING UPPER TROF ACRS CENTRAL CANADA
AND INTO THE WESTERN GRT LKS STILL ON TRACK TO SHUNT AN ARCTIC
FRONT THROUGH THE CWA BY FRI MORNING. VARYING AMOUNTS OF STRATUS
AHEAD OF THIS PROCESS THU EVENING...AND PRE-FRONTAL SOUTHWEST SFC
FLOW MAY HELP TEMPS FROM BOTTOMING OUT THU NIGHT BUT MAY STILL LEAN
TOWARD THE COOLER SIDE OF GUIDANCE AS A BUFFER AGAINST SOME SFC WIND
DECOUPLE IN A DRY SFC LAYER. STEEPENING CYCLONIC FLOW IN A POST-
FRONTAL REGIME AND VORT SPOKE WILL LOOK TO WRING OUT LIGHT SNOW AND
FLURRIES OUT OF ANY POST-FRONTAL STRATUS ON FRI. BREAKS IN CLOUD
COVER AND PROJECTED STEEP LLVL LAPSE RATES MAY MAKE FOR MORE OF A
DIURNAL SNOW SHOWER ACTIVITY AS OPPOSED TO STRATIFORM SNOW ESPECIALLY
ACRS THE NORTHEAST TO EASTERN HALF OF THE DVN CWA. COLD AND BLUSTERY
POST-FRONTAL CONDITIONS WITH HIGHS IN MAINLY IN THE 20S AND
NORTHWEST WINDS OF 15 TO 25 MPH. CLEAR OUT FRI NIGHT AS STRONG 1040+
MB HIGH PRESSURE COMPLEX BUILDS DOWN ACRS THE PLAINS AND UPPER MS RVR
VALLEY INTO SAT MORNING.WITH EXTENT OF INCOMING SFC RIDGE PRESSURE
GRADIENT...EXPECT SOME MIXING NORTH WINDS TO MAINTAIN OVERNIGHT FRI
INTO EARLY SAT MORNING TO PREVENT A BOTTOM OUT IN THE LOW SINGLE
DIGITS OR EVEN BELOW ZERO. MAY STILL GO WITH LOW SINGLE DIGITS IN THE
FAR NORTHWESTERN CWA...TO THE LOWER TEEN IN THE SOUTHEAST.
SATURDAY AND SUNDAY...SREF AND LATEST SUITE OF 12Z RUN MEDIUM RANGE
MODELS IN GOOD AGREEMENT OF SUGGESTING BOUT OF RIDGING TO MAKE FOR A
FAIR BUT CHILLY WEEKEND. BRUNT OF HIGH PRESSURE CENTER PROJECTED TO
SHUTTLE TO THE SOUTH OF THE AREA ACRS THE LOWER MS RVR VALLEY ON SAT
WITH RIDGE LOBE EXTENDING THIS FAR NORTH. MAINLY SUNNY SKIES...LACK
OF SNOW COVER AND CONTINUED MIXING NORTHWEST WINDS OF 10-20 MPH
THROUGH AT LEAST MID AFTERNOON WILL HELP TEMPS GET INTO THE LOW TO
MID 20S...OTHERWISE EXTENT OF COLD AIRMASS IN PLACE WOULD WARRANT
HIGHS IN THE TEENS. SAT NIGHT MAY BE THE COLDEST NIGHT/SECOND NIGHT
AFTER COLD FRONT RULE. CHANCE OF NEAR ZERO OR SUB-ZERO TEMPS IN
NORTHERN PORTIONS OF THE CWA ESPECIALLY IN COLD AIR DRAINAGE
LOCALS. LIGHT RETURN FLOW BEHIND PASSING RIDGE AXIS TO HELP TEMPS
ON SUNDAY REACH THE MID TO UPPER 20S...BUT EXPECT INCREASING HIGH
CLOUDS IN THE AFTERNOON AHEAD OF SOUTHERN STEAM WAVE DEVELOPING
ACRS THE EASTERN GRT BSN. DEPENDING ON EXITING TIMING OF THE ROBUST
HIGH PRESSURE COMPLEX...FIRST BOUT OF OVERRUNNING SNOWS MAY GET CLOSE
TO OR EVEN INTO THE WESTERN CWA LATE SUNDAY NIGHT BUT FOR NOW WILL
BANK ON THE STRENGTH AND SLOWNESS OF THE DENSE RIDGE.
MONDAY THROUGH WEDNESDAY...BOTH THE 12Z RUN GFS AND ECMWF ARE
TRENDING TOWARD ROLLING A LARGE CHUNK OF THE SOUTHERN STREAM WAVE
OUT OVER THE REGION MON INTO TUE MORNING. SOME MOISTURE DRAW IN
INCREASING WARM MOIST CONVEYOR UP OFF THE WESTERN GULF BEHIND
RETREATING RIDGE COMPLEX WILL FUEL ANY ISENTROPIC LIFT OR ELEVATED
FORCES AHEAD OF THIS WAVE. EARLY INDICATIONS BY LATEST 12Z RUN
MODELS ESPECIALLY THE WETTER ECMWF NOW SUGGEST 2-4 INCHES OF SNOW
POSSIBLE ON MONDAY AND INTO MONDAY NIGHT. WILL CONTINUE TO TREND
UP THE POPS BUT SOME TIMING AND MOISTURE INFLUX STILL YET TO EB
REFINED OVER THE NEXT 24-48 HRS. WITH THE CURRENT EXPECTED TIMING...
SNOW SHOULD BE EAST OF THE CWA BY TUE MORNING AND WILL GO DRY WITH
WAKE RIDING. SOUTHWESTERN TROF/SOUTHERN STEAM RELOADS BY MID NEXT
WEEK WITH ANOTHER EVEN LARGER SYSTEM POSSIBLE WED THROUGH THU
DEPENDING ON PHASING OF COURSE. ..12..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
601 PM MST FRI FEB 10 2012
.UPDATE...
600 PM MST FRI FEB 10 2012
STARTING GET A NICE NW-SE NARROW BAND OF SNOW FROM YUMA COUNTY
THROUGH SAINT FRANCIS TOWARD COLBY IN GOOD 700 FRONTOGENESIS FROM
GFS AND MID TO RIGHT REAR PORTION OF UPPER JET. YUMA WEB-CAM
SHOWING ROADS COVERED WITH PROBABLY AN INCH OR SO ALREADY ON THE
GROUND.
HAVE BUMPED UP SNOWFALL AMOUNTS SLIGHTLY...ESPECIALLY THROUGH 06Z
GIVEN RADAR AND MODEL TRENDS. ALSO BUMPED UP POPS INTO THE LIKELY
TO CATEGORICAL RANGE WHERE CONFIDENCE HIGHEST THAT THE CURRENT
BAND OF SNOW IS AND IS EXPECTED TO BE THROUGH EARLY TONIGHT. AS
DRIER AIR MOVES IN FROM THE NORTH BETTER CHANCES OF SNOW WILL
SHIFT SOUTHWEST OF CURRENT POSITION.
WILL AWAIT 00Z DATA BEFORE ADDRESSING TEMPS AND WINDS BUT I DID
TWEAK DEWPOINTS DOWN BASED ON CURRENT OBS WHICH ARENT TOO FAR OFF
FROM MET/MAV GUIDANCE.
007
&&
.SYNOPSIS...
ISSUED AT 222 PM MST FRI FEB 10 2012
EARLY AFTERNOON WV IMAGERY AND RUC H5 ANALYSIS SHOW LARGE SCALE
TROUGH ACROSS SOUTHERN CANADA EXTENDING SOUTH ACROSS THE GREAT
LAKES AND NORTHERN PLAINS. AT THE SURFACE THE COLD FRONT THAT
PASSED THROUGH THE CWA THIS MORNING HAS STALLED ALONG THE W/SW
PART OF THE CWA.
&&
.DISCUSSION...
553 PM MST FRI FEB 10 2012
99
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 222 PM MST FRI FEB 10 2012
TONIGHT THROUGH EARLY SATURDAY...A FRONTAL BOUNDARY WILL REMAIN
NEARLY STATIONARY ACROSS THE HIGHER TERRAIN OF THE CENTRAL HIGH
PLAINS. EXPECT AREAS OF LIGHT SNOW TO DEVELOP OVERNIGHT IN THE
VICINITY OF THIS BOUNDARY AS WEAK WAVES MOVE THROUGH THE NORTHWEST
FLOW ALOFT. THERE IS A SLIGHT CHANCE OF SOME FREEZING FOG IN VERY
CLOSE PROXIMITY TO THE FRONT OVERNIGHT OVER FAR EASTERN COLORADO
WHERE THE LOW CLOUDS WILL INTERSECT THE TERRAIN. HAVE TRIMMED THE
AREAS OF FREEZING FOG DOWN SOME...BUT HAVE KEPT IT IN THERE. THE
AIRMASS BEGINS DRYING OUT OVERNIGHT AS THE COLD AIR CONTINUES TO
PUSH FURTHER INTO THE REGION...SO HAVE DECREASED PRECIPITATION AND
CLOUD COVER FROM NORTHEAST TO SOUTHWEST OVERNIGHT THROUGH EARLY
SATURDAY MORNING.
LOCKHART
SATURDAY THROUGH SATURDAY NIGHT...WITH BAROCLINIC ZONE AND
LINGERING H85-H7 FRONTOGENSIS ACROSS THE WESTERN CWA...CANT RULE
OUT CONTINUED LIGHT SNOW THROUGH MID AFTERNOON SATURDAY. AIRMASS
CONTINUES TO DRY OUT THROUGH MIDDAY FROM THE NORTHEAST...SO I HAVE
KEPT CHANCE MENTION LIMITED TO FAR WESTERN CWA THROUGH 21Z. WITH
LINGERING CLOUD COVER AND VERY COLD AIRMASS IN PLACE TEMPERATURES
WILL STRUGGLE TO WARM MUCH. CURRENT FORECAST ALLOWS FOR SOME
DIURNAL WARMING WITH TEMPS IN THE MID TEENS TO LOW 20S ACROSS MUCH
OF THE CWA...AND AROUND 12 NEAR MCCOOK. CONSIDERING THE COLD
AIRMASS ALOFT AND LINGERING LOW CLOUDS...THIS MAY BE TOO
OPTIMISTIC. MODEL SOUNDINGS STILL SHOWING WARM LAYER ABOVE H85
ACROSS THE WESTERN PARTS OF THE CWA SATURDAY NIGHT...WITH SHALLOW
COLD NEAR SATURATED LAYER BELOW THIS. WITH UPSLOPE STILL
PERSISTING ALONG BAROCLINIC ZONE IN EASTERN COLORADO CANT RULE
OUT FREEZING FOG OR FREEZING DRIZZLE THROUGH EARLY SUNDAY MORNING.
I SAW NO NEED TO MAKE ANY MAJOR CHANGES TO PREVIOUS FORECAST WHICH
ALREADY HAD AREAS OF FREEZING FOG/DRIZZLE SATURDAY NIGHT THROUGH
EARLY SUNDAY MORNING.
DR
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 222 PM MST FRI FEB 10 2012
SUNDAY THROUGH MONDAY...SHORTWAVE RIDGING SHOULD KEEP CONDITIONS
DRY DURING THE DAY SUNDAY...WITH TEMPERATURES MODERATING ALOFT
FROM THE WEST. LINGERING CLOUD COVER WILL STILL LIMIT THE AMOUNT
OF DIURNAL WARMING AT THE SURFACE...SO TEMPS WILL LIKELY STILL
REMAIN BELOW FREEZING IN THE E/NE HALF OF THE CWA. A SHORTWAVE
TROUGH WILL MOVE IN THE REGION BY SUNDAY NIGHT. THIS SYSTEM DOES
NOT APPEAR TO BE VERY WELL ORGANIZED WITH MAIN H25-H3 JET OVER
OKLAHOMA PANHANDLE. THERE STILL APPEARS TO BE ENOUGH LIFT/MOISTURE
THAT I CANT RULE OUT SNOW SUNDAY NIGHT THROUGH MONDAY MORNING. BY
MONDAY AFTERNOON SHORTWAVE RIDGING BUILDS BACK OVER CWA.
TUESDAY THROUGH FRIDAY...SPLIT FLOW DOMINATES THE PATTERN
THROUGH THE REMAINING EXTENDED PERIODS. WHILE GUIDANCE IN MODERATE
AGREEMENT ON THE OVERALL PATTER...THERE IS VERY POOR RUN TO RUN
CONSISTENCY IN REGARDS TO THE HANDLING OF SMALLER SCALE FEATURES.
BEST CHANCE FOR PRECIP STILL APPEARS TO BE TUESDAY NIGHT THROUGH
WEDNESDAY NIGHT AS A SERIES OF SHORTWAVE TROUGHS MOVE THROUGH THE
PLAINS. POSITION/TIMING OF THESE FEATURES HAS BEEN ALL OVER THE
PLACE THE LAST FEW DAYS. THE 00Z ECMWF AND 00Z/12 GFS WERE
STARTING TO SHOW SIMILAR TRENDS FOR PRECIP OVER OUR CWA...WITH
LIGHT SNOW PREDOMINATELY OVER THE SOUTHERN HALF OF THE CWA QUICKLY
EXITING THE REGION BY TUESDAY AFTERNOON/WEDNESDAY NIGHT. THE 12Z
ECMWF AND GEM ARE BOTH MUCH MORE BULLISH WITH THIS SYSTEM
PRODUCING A CLOSED H5 CENTER AND MUCH MORE PRECIPITATION...WITH
THE 12Z ECMWF FURTHER NORTH AND LINGERS PRECIP THROUGH THURSDAY.
THIS IS SIGNIFICANT DEVIATION FROM PREVIOUS RUN AND ENSEMBLE DATA.
CONFIDENCE IS PRETTY LOW RIGHT NOW IN ANY PARTICULAR SOLUTION AT
THIS POINT CONSIDERING THE CHAOTIC NATURE OF THIS TYPE OF PATTER.
I KEPT THE FORECAST ON THE CONSERVATIVE END OF THE MODEL
SPREAD...WITH SLIGHT CHANCE POPS TUESDAY NIGHT THROUGH WEDNESDAY
NIGHT. TEMPERATURES THROUGH THIS PERIOD SHOULD REMAIN SLIGHTLY
BELOW NORMAL WITH HIGHS IN THE UPPER 30S/LOW 40S.
DR
&&
.AVIATION...
1226 PM MST FRI FEB 10 2012
AREAS OF LOW CLOUDS HAVE BECOME LESS EXTENSIVE THROUGH THE
MORNING...BUT ARE EXPECTED TO RETURN OVERNIGHT ALONG WITH A
POSSIBILITY OF LIGHT SNOW IN THE VICINITY OF A COLD FRONT DRAPED
ACROSS THE CENTRAL HIGH PLAINS. CHANCES OF LIGHT SNOW AND LOWER
FLIGHT CATEGORIES WILL BE GREATER AT KGLD IN CLOSER PROXIMITY TO
THE FRONT.
VFR CONDITIONS WILL CONTINUE AT BOTH KGLD AND KMCK THROUGH 00Z.
AFTER 00Z...EXPECT LOW CLOUDS AND LOWER VISIBILITIES TO BECOME
MORE EXTENSIVE AS AREAS OF LIGHT SNOW DEVELOP AND PERSIST THROUGH
ABOUT 06Z IN THE VICINITY OF THE FRONTAL BOUNDARY THAT HAS STALLED
OVER EASTERN COLORADO. KMCK WILL SEE MVFR CONDITIONS WHILE KGLD
WILL BE MVFR WITH OCCASIONAL IFR WITH LIGHT SNOW THROUGH ABOUT
12Z. KMCK WILL IMPROVE TO VFR CONDITIONS AGAIN BY 12Z WHILE KGLD
WILL BE SLOWER TO IMPROVE WITH MVFR CONDITIONS AFTER ABOUT 14Z.
LOCKHART
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
NE...NONE.
CO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS WICHITA KS
325 AM CST THU FEB 9 2012
.DISCUSSION...
MAIN FORECAST CHALLENGES CONTINUE TO BE TEMPERATURES UNDER THE COLD
SURGE TONIGHT AND INTO THE WEEKEND AND THE MULTIPLE WAVES OF
PRECIPITATION POSSIBLE LATE IN THE WEEKEND AND MID NEXT WEEK.
SYNOPSIS:
UPPER LEVEL ENERGY IS MOVING EASTWARD ACROSS IOWA WHILE THE NEXT
WAVE TO IMPACT THE REGION IS SETTING UP ACROSS THE INTER-MOUNTAIN
WEST. AT THE SURFACE...HIGH PRESSURE IS SLIDING EASTWARD INTO
IOWA. UNDER THIS HIGH PRESSURE...LOW STRATUS...REMNANT FROM
TUESDAY...CONTINUES TO STICK AROUND ACTING LIKE A BLANKET KEEPING
OVERNIGHT TEMPERATURES WARMER.
TODAY - SATURDAY:
MAIN FORECAST CHALLENGE FOR THE SHORT TERM INVOLVES LINGERING CLOUD
COVER FOR TODAY...AND THE TEMPERATURES ASSOCIATED WITH THE ARCTIC
AIRMASS IN PLACE FRIDAY AND SATURDAY.
LOW LEVEL MOISTURE REMAINS TRAPPED IN A TEMPERATURE INVERSION
UPSTREAM AS FAR AS SOUTHEASTERN COLORADO. WESTERLY/SOUTHWESTERLY
FLOW THURSDAY SHOULD HELP SCOUR OUT SOME OF THOSE CLOUDS...BUT A
WEAK SHORTWAVE CURRENTLY DEVELOPING OVER THE FOUR CORNERS AREA WILL
KEEP SOME ELEVATED CLOUD COVER THROUGHOUT THE DAY. THEREFORE HAVE
KNOCKED THE HIGH TEMPERATURES DOWN A FEW DEGREES FOR TODAY.
POLAR VORTEX OVER HUDSON BAY IS STILL EXPECTED TO EJECT A SHORTWAVE
TROUGH OVER THE GREAT LAKES TO BEGIN THE WEEKEND...WHICH WILL DRAG A
STRONG COLD FRONT SOUTH ACROSS THE AREA STARTING FRIDAY MORNING.
LITTLE MOISTURE WILL ONLY PRODUCE SOME MID TO HIGH LEVEL
CLOUDS...AND GUSTY NORTH-NORTHEAST WINDS WILL FOLLOW THIS FRONT
THROUGH SATURDAY.
ARL
SUNDAY - MONDAY:
THE NEXT IN A SERIES OF UPPER LEVEL WAVES WILL IMPACT THE SOUTHERN
CONUS LATE SUNDAY AND INTO MONDAY. THE MEDIUM RANGE MODELS HAVE
BEEN CONSISTENT OVER THE PAST FEW DAYS SHOWING THIS SYSTEM...BUT
THEY HAVE SLOWED SLIGHTLY FROM EARLIER RUNS. THE GFS CONTINUES TO BE
WARMER THAN THE ECMWF WITH THE SYSTEM. THESE DISCREPANCIES COULD
MEAN A DIFFERENCE BETWEEN RAIN AND SNOW. THE WARMER GFS IS PUSHING
TOWARD THE MAGIC FREEZING LINE WHICH COULD CAUSE A MIXTURE OF
PRECIPITATION...BUT HAVE KEPT THIS FORECAST COOLER THAN THE
GFS...TRENDING TOWARD THE ECMWF. GUIDANCE CONTINUES TO SHOW A LACK
OF A STRONG ENOUGH WARM LAYER TO BRING FREEZING RAIN INTO THE
MIX...AND HAVE KEPT MUCH OF THE PRECIPITATION EVENT SNOW. AS WARM
AIR ADVECTION STREAMS NORTHWARD MONDAY AFTERNOON...EXPECTING A
CHANGE OVER FROM SNOW TO RAIN. IT IS STILL TOO FAR OUT TO DETERMINE
SNOW AMOUNTS AND MODEL VARIATIONS FROM RUN TO RUN ALSO PROHIBIT A
GOOD ESTIMATION...BUT TRENDS OVER THE PAST FEW DAYS SHOW THAT THE
EVENT COULD BRING SNOW ACCUMULATIONS IN THE ADVISORY CATEGORY...WITH
2-5 INCHES POSSIBLE. BETTER ESTIMATIONS WILL BE AVAILABLE AS THE
SYSTEM NEARS. PRECIPITATION WILL EXIT MONDAY EVENING AS THE SYSTEM
MOVES TO THE EAST.
TUESDAY - WEDNESDAY:
A BREAK IN THE ACTIVE WEATHER IS SHORT LIVED AS THE NEXT WAVE MOVES
IN FROM THE SOUTHWEST U.S. TUESDAY NIGHT. THE GUIDANCE HAS SLOWED
WITH THIS SYSTEM AS WELL...AND INTER-OFFICE COLLABORATION WAS TO KEEP
TUESDAY AND TUESDAY NIGHT DRY. EARLY WEDNESDAY MORNING
PRECIPITATION IS EXPECTED TO MOVE NORTHWARD AS THE SYSTEM LIFTS
NORTHEAST OUT OF SOUTHERN NEW MEXICO. AT THIS POINT IN TIME THE
SYSTEM LOOKS TO BE WARM ENOUGH THAT THE MAIN PRECIPITATION TYPE WILL
BE RAIN FOR WEDNESDAY. HOWEVER...DUE TO THIS BEING DAY 7 AND THE
MODEL VARIATIONS CONFIDENCE IN WEDNESDAYS SYSTEM IS LOW.
BILLINGS
&&
.FIRE WEATHER...
FIRE CONDITIONS ARE EXPECTED TO REMAIN LOW THROUGHOUT THE FORECAST
PERIOD. GUSTY NORTH WINDS AND LOW DEWPOINTS FOLLOWING THE COLD
FRONT THIS FRIDAY AND SATURDAY MAY ELEVATE CONDITIONS SLIGHTLY...BUT ALL
GFDI INDEXES REMAIN IN THE LOW CATEGORY.
ARL
&&
.AVIATION...06Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
MAIN AVIATION HAZARD: MVFR STRATUS.
MVFR STRATUS (EXCEPT LOW VFR AT CNU) SHOULD PERSIST OVERNIGHT INTO
THURSDAY MORNING AT LEAST...WITH WEAK ISENTROPIC UPGLIDE PATTERN
IN THE LOW-MID LEVELS. RUC BUFKIT SOUNDINGS SEEM TO HAVE DECENT
HANDLE ON THIS. SOUTHWESTERLY WINDS THURSDAY MAY AIDE IN CLEARING
THE LOW CLOUDS NORTHEASTWARD INTO OUR AREA BY LATE AFTERNOON. MID-HIGH
LEVEL CLOUDS WILL CONTINUE TO BLANKET MUCH OF AREA WITH SHORTWAVE
TROF DROPPING OUT OF THE CENTRAL ROCKIES INTO THE SOUTHERN PLAINS.
THE RAIN/SNOW FROM THIS SHORTWAVE IS EXPECTED TO MISS OUR TAF
SITES TO THE SOUTH IN OKLAHOMA.
JMC
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 44 25 37 17 / 10 10 0 0
HUTCHINSON 42 24 34 14 / 0 0 0 0
NEWTON 43 24 32 15 / 0 0 0 0
ELDORADO 45 25 35 16 / 0 10 0 0
WINFIELD-KWLD 45 28 40 19 / 10 20 10 0
RUSSELL 39 19 28 11 / 0 0 0 20
GREAT BEND 39 21 30 13 / 10 10 0 20
SALINA 40 22 30 12 / 0 0 0 10
MCPHERSON 42 23 32 13 / 0 0 0 0
COFFEYVILLE 47 33 44 19 / 10 20 10 0
CHANUTE 46 29 39 16 / 0 10 10 0
IOLA 45 28 37 15 / 0 0 10 0
PARSONS-KPPF 46 31 41 18 / 0 20 10 0
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS WICHITA KS
1140 PM CST WED FEB 8 2012
.AVIATION...06Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
MAIN AVIATION HAZARD: MVFR STRATUS.
MVFR STRATUS (EXCEPT LOW VFR AT CNU) SHOULD PERSIST OVERNIGHT INTO
THURSDAY MORNING AT LEAST...WITH WEAK ISENTROPIC UPGLIDE PATTERN
IN THE LOW-MID LEVELS. RUC BUFKIT SOUNDINGS SEEM TO HAVE DECENT
HANDLE ON THIS. SOUTHWESTERLY WINDS THURSDAY MAY AIDE IN CLEARING
THE LOW CLOUDS NORTHEASTWARD INTO OUR AREA BY LATE AFTERNOON. MID-HIGH
LEVEL CLOUDS WILL CONTINUE TO BLANKET MUCH OF AREA WITH SHORTWAVE
TROF DROPPING OUT OF THE CENTRAL ROCKIES INTO THE SOUTHERN PLAINS.
THE RAIN/SNOW FROM THIS SHORTWAVE IS EXPECTED TO MISS OUR TAF
SITES TO THE SOUTH IN OKLAHOMA.
JMC
&&
.PREV DISCUSSION... /ISSUED 543 PM CST WED FEB 8 2012/
AVIATION...00Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
MAIN EXPECTED AVIATION HAZARD: MVFR STRATUS.
POLAR SURFACE HIGH WILL REMAIN ACROSS CENTRAL/EASTERN KS OVERNIGHT
BEFORE SHIFTING OFF TO THE EAST ON THURSDAY. ISENTROPIC LIFT
SHOULD SERVE TO KEEP INVERSION IN PLACE OVERNIGHT FROM 850-750 MB.
THEREFORE WILL KEEP MVFR STRATUS IN TACT IN FORECAST OVERNIGHT
WITH ANTICIPATION THAT IT SHOULD DISSIPATE THURSDAY AS LOW-LEVEL
FLOW BECOMES SOUTHWEST-WESTERLY.
JMC
PREV DISCUSSION... /ISSUED 315 PM CST WED FEB 8 2012/
DISCUSSION...
MAIN FORECAST CHALLENGES WILL BE TEMPS FOR THE WEEKEND WITH OUR NEXT
POLAR SURGE WITH ATTENTION TURNING TO PRECIP CHANCES AND TYPE FOR
SUN-MON.
SYNOPSIS:
ONE SHORTWAVE IS TRACKING EAST OVER THE OHIO VALLEY WITH ANOTHER PIECE
OF ENERGY DIVING SOUTHEAST OVER WESTERN SD/NW NEBRASKA. MEANWHILE
ANOTHER UPPER IMPULSE EXTENDS OVER THE NORTHERN INTERMOUNTAIN INTO
THE CENTRAL GREAT BASIN. AT THE SURFACE THE HIGH IS CENTERED OVER NW
MO/SW IA WITH SOME RETURN FLOW COMMENCING OVER THE HIGH PLAINS.
TONIGHT-THU:
THE SHORTWAVE ENERGY OVER THE DAKOTAS IS EXPECTED TO MAINTAIN ITS
QUICK SOUTHEAST PROGRESSION AND WILL BE OVER THE MISSOURI VALLEY BY
THU MORNING. AT THE SAME TIME ADDITIONAL UPPER ENERGY WILL MOVE INTO
THE SOUTHERN ROCKIES BY THU MORNING. THIS FEATURE WILL SPREAD PRECIP
CHANCES OVER THE SOUTHERN PLAINS. HOWEVER AT THIS TIME FEEL
CONFIDENT ENOUGH IN THE PRECIP STAYING SOUTH TO KEEP OUT OF THE
FORECAST FOR NOW. A BRIEF WARMUP WILL AFFECT THE AREA THU WITH A RETURN
TO MORE SEASONAL TEMPS.
FRI-SAT:
THE MAIN THEME THROUGH THESE PERIODS WILL BE FOR ARCTIC AIR TO
INVADE THE AREA.
SHORTWAVE ENERGY IS EXPECTED TO DIVE OUT OF ALBERTA/SASKATCHEWAN AND
INTO THE NORTHERN PLAINS THU NIGHT. THIS WILL PULL THE POLAR VORTEX
TO THE SOUTHWEST WHICH WILL ALLOW SOME VERY COLD AIR TO SPILL SOUTH
ON FRI WITH THE FRONT PASSING THROUGH THE FORECAST AREA DURING THE
DAY. CONFIDENCE IS VERY HIGH THAT WELL BELOW NORMAL TEMPS WILL BE IN
PLACE FOR BOTH FRI AND ESPECIALLY SAT WHICH AGREES WELL WITH FORECASTED
STANDARDIZED ANOMALIES.
SUN-WED:
THE FOCUS OF THESE PERIODS WILL BE A FAST MOVING WAVE THAT IS
EXPECTED TO SPREAD SOME PRECIP ACROSS THE AREA FOR THE SUN NIGHT-MON
TIME FRAME. BOTH THE GFS AND ECMWF AGREE ON TRACKING THIS SYSTEM
ACROSS THE DESERT SW ON SUN AND KICKING OUT INTO THE SOUTHERN HIGH
PLAINS ON SUN NIGHT. THIS WILL PLACE THE BEST LIFT OVER THE AREA FOR
SUN NIGHT INTO MON. THE MAIN QUESTION WILL BE PRECIP TYPE. THE
EXPECTED SETUP IS TYPICALLY NOT CONDUCIVE FOR A WIDESPREAD FREEZING
RAIN WITH THE LACK OF NEUTRAL OR COLD ADVECTION UNDER THE SW
FLOW ALOFT. THE PROGRESSIVE NATURE OF THIS SYSTEM ALSO DOES NOT
FAVOR A WIDESPREAD FREEZING RAIN EPISODE. CURRENT THINKING IS THAT WE
COULD BE LOOKING AT AN ADVISORY TYPE EVENT WITH SNOW THE PREDOMINANT
PRECIP TYPE.
MEDIUM RANGE MODELS ARE FORECASTING ANOTHER SHORTWAVE TO KICK OF THE
ROCKIES ON TUE NIGHT INTO WED. HOWEVER THERE IS CONSIDERABLE
DIFFERENCES BETWEEN THE GFS AND ECMWF WITH REGARDS TO TIMING WITH
THE GFS MUCH MORE PROGRESSIVE.
FIRE WEATHER...
FIRE DANGER CONCERNS ARE EXPECTED TO REMAIN MINMAL FOR THE NEXT
COULE OF DAYS. RH`S ARE EXPECTED TO REMAIN ELEVATED FOR BOTH THU
AND FRI DUE TO TEMPS NOT CLIMBING MUCH ABOVE NORMAL. WINDS FOR THU
WILL TURN TO THE WEST AND SOUTHWEST BUT WILL REMAIN LIGHT...IN THE
8-11 MPH RANGE. A VERY STRONG COLD FRONT WILL PASS THROUGH THE
AREA ON FRI WITH WIND FLIPPING AROUND TO THE NORTH.
LAWSON
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 28 47 25 38 / 0 10 10 0
HUTCHINSON 27 47 24 35 / 0 0 0 0
NEWTON 27 47 24 35 / 0 0 0 0
ELDORADO 28 47 25 37 / 0 0 10 0
WINFIELD-KWLD 29 49 28 41 / 0 10 10 10
RUSSELL 22 40 19 31 / 0 0 0 0
GREAT BEND 24 43 21 33 / 0 10 10 0
SALINA 26 43 22 33 / 0 0 0 0
MCPHERSON 27 46 23 34 / 0 0 0 0
COFFEYVILLE 30 49 33 43 / 0 10 10 10
CHANUTE 29 48 29 39 / 0 0 10 10
IOLA 28 48 28 38 / 0 0 0 10
PARSONS-KPPF 30 49 31 41 / 0 0 10 10
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
954 PM MST WED FEB 8 2012
.UPDATE...
841 PM MST WED FEB 8 2012
JUST COMPLETED ANOTHER UPDATE. WAS SKEPTICAL OF EARLIER MODEL DATA
IN REGARDS TO FOG FORMATION SINCE IT OVERDID IT LAST NIGHT.
HOWEVER...SOME FOG HAS DEVELOPED IN THE SOUTHERN PORTION OF THE
FORECAST AREA. THIS DOES MAKE SENSE WITH AREA SOUNDINGS. LATEST
HRRR CATCHES THIS AREA AND EXPANDS IT NORTHEAST AHEAD OF THE
INCOMING SURFACE TROUGH LINE. THIS MAKES SENSE SO HAVE INSERTED
PATCHY FZFG FROM NOW INTO TOMORROW MORNING.
BULLER
&&
.DISCUSSION...
235 PM MST WED FEB 8 2012
TONIGHT...SHORTWAVE TROUGH PASSES JUST NORTH OF CWA OVERNIGHT. A
WARM FRONT ON THE BACK SIDE OF THIS FEATURE WILL LIFT NORTHEAST
ACROSS THE CWA 00-06Z...WITH SURFACE HIGH PRESSURE CENTER SHIFTING
EAST TOWARDS NORTHERN MISSOURI. NAM IS SHOWING MODERATE AMOUNT OF
MID LEVEL MOISTURE OVER EASTERN CWA THIS EVENING...POSSIBLY
SUPPORTING A FEW FLURRIES. NOT REALLY CONFIDENT IN THIS. LOW STRATUS
CONTINUES TO LINGER ACROSS MOST OF THE CWA ALONG THE EASTERN EDGE OF
THIS SURFACE HIGH. AS WARM FRONT LIFTS ACROSS AREA NAM/GFS SHOW BL
MOISTURE DECREASING FROM THE WEST TO THE EAST...WITH STRATUS
POSSIBLY LINGERING OVER EASTERN LOCATIONS. LATEST HRRR BEGINNING TO
SHOW FOG DEVELOPMENT AHEAD OF THIS FRONT DURING THE EVENING
HOURS...WITH RUC FAVORING STRATUS. I WASNT CONFIDENT ENOUGH TO ADD
FOG MENTION DURING THIS CYCLE...THOUGH THERE COULD BE A BRIEF
WINDOW.
FRIDAY THROUGH TUESDAY...FORECAST CONCERNS THROUGH THE END OF THE WEEK
AND INTO THE FIRST PART OF NEXT WEEK ARE TEMPERATURES.
NORTHWEST FLOW WILL PERSIST ALOFT ACROSS THE REGION THROUGH
SATURDAY WITH A SHORT WAVE RIDGE MOVING EAST OF THE ROCKIES AND
ACROSS THE CENTRAL PLAINS SATURDAY NIGHT AND SUNDAY. AT THE
SURFACE...A TROUGH MOVES ACROSS THE REGION ON FRIDAY WITH COLDER
AIR BEGINNING TO MOVE INTO THE PLAINS STATES AND BACKING INTO THE
CENTRAL HIGH PLAINS REGION FRIDAY THROUGH FRIDAY NIGHT AND
SATURDAY. AS THIS COLD AIR IS MOVING INTO THE REGION...A WEAK
DISTURBANCE IN THE NORTHWEST FLOW MAY CREATE SOME VERY LIGHT SNOW
IN THE VICINITY OF THE FRONTAL BOUNDARY PUSHING WESTWARD. THERE
MAY BE A POSSIBILITY OF SOME LIGHT FREEZING PRECIPITATION AS IT
INITIATES GIVEN THE MODEL SOUNDINGS WERE HINTING AT WARMER AIR
ALOFT WITH A SHALLOW COLD LAYER AT THE SURFACE...BUT CONFIDENCE AT
THIS POINT IS LOW IN THIS OCCURRING AND HAVE KEPT IT AS ALL LIGHT
SNOW.
A SERIES OF SHORT WAVE TROUGHS MOVES THROUGH THE FLOW LATE IN THE
WEEKEND AND INTO THE BEGINNING OF NEXT WEEK...SO HAVE KEPT AT LEAST
A SLIGHT CHANCE OF VERY LIGHT SNOW IN THE FORECAST THROUGH SUNDAY
NIGHT. HAVE A BRIEF BREAK MONDAY AS A SHORT WAVE RIDGE MOVES
ACROSS THE FORECAST AREA WITH MORE LIGHT SNOW ON TUESDAY WITH THE
NEXT SHORT WAVE TROUGH.
LOCKHART
&&
.AVIATION...
954 PM MST WED FEB 8 2012
FOR THE 06Z TAFS...HIGH PRESSURE WILL MOVE TO THE EAST AS A MID
LEVEL DISTURBANCE AND ASSOCIATED SURFACE TROUGH MOVE INTO THE
AREA THURSDAY. WINDS WILL SWITCH FROM THE SOUTH TONIGHT TO THE
NORTHWEST BY THURSDAY LATE MORNING. STRATUS HAS BEEN SLOWLY MOVING
WESTWARD FROM CENTRAL INTO WESTERN KANSAS AND SOUTHWESTERN NEBRASKA THE
PAST FEW HOURS. WITH SOUTHWEST WINDS CURRENTLY AT KGLD...THINK
STRATUS WILL STAY TO THE EAST. FOR KMCK...CONFIDENCE IS NOT AS
HIGH FOR THE FIRST FEW HOURS UNTIL WIND DIRECTION ESTABLISHES FROM
THE SOUTHWEST. THEREFORE...HAVE INSERTED TEMPO FOR MVFR CIGS FROM
06-08Z. OTHERWISE...CONDS WILL BE VFR AT BOTH LOCATIONS.
BAS
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
NE...NONE.
CO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
716 PM EST FRI FEB 10 2012
.Update...
Issued at 715 PM EST Feb 10 2012
Regional radars this evening show the first wave of precipitation
has all but exited the forecast area. Back to the west precipitation
has increased in coverage both ahead of and just behind the cold
front. Have decreased pops over the eastern portion of the forecast
area for the next few hours ahead of this next batch of snow. With a
bit of warmer air filtering in ahead of the front, there have been
some reports of sleet in southern Indiana and west central Kentucky,
so have included this in the grids for a few hours. However, a
change over to all snow is still expected. Updated grids have
already been sent. Products will be out soon.
.Short Term (Today and Tonight)...
Updated at 317 PM EST Feb 10 2012
First in a series of mid-level wave continues to push eastward into
the lower Ohio Valley this afternoon. Out ahead of this feature,
widespread precipitation shield has been affecting southern Indiana
and central Kentucky this afternoon. Colder thermal profiles across
the north have resulted in precipitation remaining in the form of
snow. However, across southern Kentucky, slightly warmer air aloft
has worked into that region which has resulted in a mix of rain
and/or just plain rain in areas down around Bowling Green and
Glasgow. This band of precipitation continues to head east and will
likely clear the I-65 corridor by 5PM EST and the Bluegrass region
by 7-8 PM tonight. Temperatures this afternoon have warmed into the
upper 30s in the west and with lower 30s in the east. Temperatures
have been taking a dip when the snow bands have moved through...then
have rebounded by a couple of degrees once the precipitation had
ended. For the remainder of the afternoon...we expect temperatures
to remain close to their current values and actually rise a degree
or two once the precipitation has ended as southerly flow attempts
to bring a little warmer air into the area ahead of the approaching
cold front to the northwest of the region. Snowfall accumulations
of a dusting or so will be possible with this afternoon snow
activity...but do not be surprised to see it melt rather quickly
once the precipitation ends. With temps expected to remain above
freezing this afternoon and this evening...am not anticipating much
in the way of travel problems for the afternoon rush and for evening
activities.
For Tonight, the next weather feature will be a strong cold front
that will surge through the region. Currently the front out to our
west near St. Louis. The front has been moving a bit slower than
the models had been forecasting an it is expected to hit our area a
little later than previously forecast. As the front approaches,
temperatures will likely rise slightly and we`ll see a return of
snow showers. The front looks to pass through the I-65 corridor
between 11P-12A EST tonight and then through the I-75 corridor by
2-3AM. Colder air will quickly rush in behind the front and
temperatures will fall into the lower 20s by sunrise on Saturday.
The latest HRRR, our local Hi-Res ARW WRF, and RUC data all show
snow shower activity occurring ahead and behind the front. Vertical
sounding profiles actually have a bit of a convective look to them
and I would not be surprised to see more of a snow shower/snow
squall type of activity to develop later tonight. In addition, the
pressure gradient will really tighten up and winds of 15-20 MPH with
gusts up to 30 MPH will be possible. These snow showers will be the
ones that bring the accumulating snow to the region. The snow
combined with temperatures falling into the lower 20s will result in
slick spots developing later tonight. Therefore we will leave the
current winter weather advisory intact...though much of the expected
snowfall and hazardous travel conditions will be delayed until later
tonight and into Saturday morning.
The front will continue to surge eastward on Saturday and
precipitation will end from west to east during the morning hours.
The models are trying to develop a fetch off of Lake Michigan.
However, the models have been often too aggressive with these during
this winter. Nonetheless...some snow shower activity looks to
persist into the morning hours on Saturday and that will likely add
a little more accumulation over in the Bluegrass region. Skies will
likely remain mostly cloudy through much of the day with
temperatures remaining in the 20s. Surface winds will remain
elevated during the day with winds of 10-20 MPH and gusts up to 25
MPH or so. This will keep wind chills down in the single digits at
times on Saturday.
As far as snowfall accumulations...the consensus guidance suggests
around an inch of accumulation for areas generally north of the WK
and BG Parkways. Little accumulation is expected in the far south
and southwest where a 1/2 inch or less will be possible. Highest
accumulations are going to be in the northeast generally east of
U.S. 27 where 1-2 inches of snowfall will be possible by the time
precipitation comes to an end on Saturday.
.Long Term (Saturday Night - Friday)...
Updated at 300 PM EST Feb 10 2012
1040mb high pressure will be over the central Plains Saturday night,
with an equally significant low off the New England coast. The
gradient in between will mean northwesterly winds that will just
start to weaken some as the night progresses. By the day Sunday, the
high will move to around Arkansas, making the strongest winds over
the Bluegrass and weaker across the southwest forecast area.
Temperatures will remain chilly however, with readings only getting
up to around freezing for highs. Wind chills Sunday morning again
look to be in the single digits for most of the area.
The next weather system to impact the region still looks to be
Monday night. Multiple waves within a strengthening southwesterly
flow will allow for precip all along the MS river valley Monday
afternoon and expect this moisture to advect east for the night.
Given forecast temperatures, expect at least a wintry mix for the
night, if not all snow for the north. By midnight, most of the
region should be into light to moderate snow. We could have another
advisory level event over southern Indiana with still some potential
over norther central Kentucky, but it is too early to be that
specific.
The difference with this system, compared to tonight`s snows, will
be that it looks to be followed by some warming for midweek. Models
are still not handling the longer term that well, so do not have
high confidence at this point. The 12Z GFS had a vortmax cross the
region Wednesday that was not in the previous forecast. the 00Z
ECMWF and now the 12Z have hinted at this as well, but there is not
much moisture associated with the impulse. Conversely, the system
that was expected for Thursday has now backed off as well in the 12Z
GFS, but the new ECMWF continues with a large storm system moving
into the midwest. Given such run-to-run inconsistency, will keep in
some precip chances each day, though with lower pops. Also, have
leaned more towards the precip type as rain, with highs into the 50s
Wednesday through Friday.
&&
.Aviation (00Z TAF Issuance)...
Updated at 615 PM EST Feb 10 2012
Snow has begun to increase in coverage ahead of a front expected to
move through the region tonight. The snow will bring reduced
visibilities at times. In the heaviest bands of snow ceilings will
drop below 1 kft. Otherwise, cigs look to be around 1000-1500 ft
overnight. Behind the front winds will shift to the northwest and
become gusty as the pressure gradient tightens up. This will be
around 05-07Z for SDF and BWG and 08-09Z for LEX. Snow will continue
off and on through the night. For tomorrow, ceilings look to become
VFR at SDF and BWG during the late morning or early afternoon. A
stratocu deck may remain at LEX through the day. Winds will continue
to be gusty through the day with gusts of 25-30 knots likely.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...WINTER WEATHER ADVISORY UNTIL NOON EST /11 AM CST/ SATURDAY FOR
INZ076>079-083-084-089>092.
KY...WINTER WEATHER ADVISORY UNTIL NOON EST /11 AM CST/ SATURDAY FOR
KYZ023>043-045>049-053>057-061>067-070>078-081-082.
$$
Update...........EER
Short Term.......MJ
Long Term........RJS
Aviation.........EER
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
615 PM EST FRI FEB 10 2012
.Short Term (Today and Tonight)...
Updated at 317 PM EST Feb 10 2012
First in a series of mid-level wave continues to push eastward into
the lower Ohio Valley this afternoon. Out ahead of this feature,
widespread precipitation shield has been affecting southern Indiana
and central Kentucky this afternoon. Colder thermal profiles across
the north have resulted in precipitation remaining in the form of
snow. However, across southern Kentucky, slightly warmer air aloft
has worked into that region which has resulted in a mix of rain
and/or just plain rain in areas down around Bowling Green and
Glasgow. This band of precipitation continues to head east and will
likely clear the I-65 corridor by 5PM EST and the Bluegrass region
by 7-8 PM tonight. Temperatures this afternoon have warmed into the
upper 30s in the west and with lower 30s in the east. Temperatures
have been taking a dip when the snow bands have moved through...then
have rebounded by a couple of degrees once the precipitation had
ended. For the remainder of the afternoon...we expect temperatures
to remain close to their current values and actually rise a degree
or two once the precipitation has ended as southerly flow attempts
to bring a little warmer air into the area ahead of the approaching
cold front to the northwest of the region. Snowfall accumulations
of a dusting or so will be possible with this afternoon snow
activity...but do not be surprised to see it melt rather quickly
once the precipitation ends. With temps expected to remain above
freezing this afternoon and this evening...am not anticipating much
in the way of travel problems for the afternoon rush and for evening
activities.
For Tonight, the next weather feature will be a strong cold front
that will surge through the region. Currently the front out to our
west near St. Louis. The front has been moving a bit slower than
the models had been forecasting an it is expected to hit our area a
little later than previously forecast. As the front approaches,
temperatures will likely rise slightly and we`ll see a return of
snow showers. The front looks to pass through the I-65 corridor
between 11P-12A EST tonight and then through the I-75 corridor by
2-3AM. Colder air will quickly rush in behind the front and
temperatures will fall into the lower 20s by sunrise on Saturday.
The latest HRRR, our local Hi-Res ARW WRF, and RUC data all show
snow shower activity occurring ahead and behind the front. Vertical
sounding profiles actually have a bit of a convective look to them
and I would not be surprised to see more of a snow shower/snow
squall type of activity to develop later tonight. In addition, the
pressure gradient will really tighten up and winds of 15-20 MPH with
gusts up to 30 MPH will be possible. These snow showers will be the
ones that bring the accumulating snow to the region. The snow
combined with temperatures falling into the lower 20s will result in
slick spots developing later tonight. Therefore we will leave the
current winter weather advisory intact...though much of the expected
snowfall and hazardous travel conditions will be delayed until later
tonight and into Saturday morning.
The front will continue to surge eastward on Saturday and
precipitation will end from west to east during the morning hours.
The models are trying to develop a fetch off of Lake Michigan.
However, the models have been often too aggressive with these during
this winter. Nonetheless...some snow shower activity looks to
persist into the morning hours on Saturday and that will likely add
a little more accumulation over in the Bluegrass region. Skies will
likely remain mostly cloudy through much of the day with
temperatures remaining in the 20s. Surface winds will remain
elevated during the day with winds of 10-20 MPH and gusts up to 25
MPH or so. This will keep wind chills down in the single digits at
times on Saturday.
As far as snowfall accumulations...the consensus guidance suggests
around an inch of accumulation for areas generally north of the WK
and BG Parkways. Little accumulation is expected in the far south
and southwest where a 1/2 inch or less will be possible. Highest
accumulations are going to be in the northeast generally east of
U.S. 27 where 1-2 inches of snowfall will be possible by the time
precipitation comes to an end on Saturday.
.Long Term (Saturday Night - Friday)...
Updated at 300 PM EST Feb 10 2012
1040mb high pressure will be over the central Plains Saturday night,
with an equally significant low off the New England coast. The
gradient in between will mean northwesterly winds that will just
start to weaken some as the night progresses. By the day Sunday, the
high will move to around Arkansas, making the strongest winds over
the Bluegrass and weaker across the southwest forecast area.
Temperatures will remain chilly however, with readings only getting
up to around freezing for highs. Wind chills Sunday morning again
look to be in the single digits for most of the area.
The next weather system to impact the region still looks to be
Monday night. Multiple waves within a strengthening southwesterly
flow will allow for precip all along the MS river valley Monday
afternoon and expect this moisture to advect east for the night.
Given forecast temperatures, expect at least a wintry mix for the
night, if not all snow for the north. By midnight, most of the
region should be into light to moderate snow. We could have another
advisory level event over southern Indiana with still some potential
over norther central Kentucky, but it is too early to be that
specific.
The difference with this system, compared to tonight`s snows, will
be that it looks to be followed by some warming for midweek. Models
are still not handling the longer term that well, so do not have
high confidence at this point. The 12Z GFS had a vortmax cross the
region Wednesday that was not in the previous forecast. the 00Z
ECMWF and now the 12Z have hinted at this as well, but there is not
much moisture associated with the impulse. Conversely, the system
that was expected for Thursday has now backed off as well in the 12Z
GFS, but the new ECMWF continues with a large storm system moving
into the midwest. Given such run-to-run inconsistency, will keep in
some precip chances each day, though with lower pops. Also, have
leaned more towards the precip type as rain, with highs into the 50s
Wednesday through Friday.
&&
.Aviation (00Z TAF Issuance)...
Updated at 615 PM EST Feb 10 2012
Snow has begun to increase in coverage ahead of a front expected to
move through the region tonight. The snow will bring reduced
visibilities at times. In the heaviest bands of snow ceilings will
drop below 1 kft. Otherwise, cigs look to be around 1000-1500 ft
overnight. Behind the front winds will shift to the northwest and
become gusty as the pressure gradient tightens up. This will be
around 05-07Z for SDF and BWG and 08-09Z for LEX. Snow will continue
off and on through the night. For tomorrow, ceilings look to become
VFR at SDF and BWG during the late morning or early afternoon. A
stratocu deck may remain at LEX through the day. Winds will continue
to be gusty through the day with gusts of 25-30 knots likely.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...WINTER WEATHER ADVISORY UNTIL NOON EST /11 AM CST/ SATURDAY FOR
INZ076>079-083-084-089>092.
KY...WINTER WEATHER ADVISORY UNTIL NOON EST /11 AM CST/ SATURDAY FOR
KYZ023>043-045>049-053>057-061>067-070>078-081-082.
$$
Short Term.......MJ
Long Term........RJS
Aviation.........EER
THE PREVIOUS SHORT TERM FORECAST DISCUSSION FOLLOWS...
/TODAY THROUGH SATURDAY/
THE PERIOD BEGINS WITH A RATHER DEEP VORTEX TO THE EAST OF THE HUDSON
BAY REGION WITH WNW FLOW ALOFT LOCALLY WITH RATHER ZONAL FLOW
ACROSS THE EASTERN CONUS. A SHORTWAVE NOW MOVING THROUGH THE ROCKY MTN
REGION IS PROGGED TO MOVE INTO THE SOUTHERN PLAINS TODAY AND THEN
REACH THE MS AND LOWER OH VALLEYS ON FRI AFTERNOON AND MOVE ACROSS
THE REGION AND THE SE STATES ON FRI EVENING. AT THE SAME TIME...A
COUPLE OF NORTHERN STREAM SHORTWAVES ROTATING AROUND THE VORTEX AND A
110 TO 120 KT JET STREAK REACHING THE DAKOTAS AND THE NORTHERN PLAINS
TONIGHT AND INTO FRI WILL ROTATE DOWN INTO THE OH VALLEY ON FRI
NIGHT AND PASS EAST ON SAT. THIS COMBINATION WILL HELP TO CARVE OUT
AN EASTERN NOAM/EASTERN CONUS TROUGH FRI NIGHT INTO SAT...THE AXIS OF
WHICH SHOULD PASS EAST OF THE REGION BY THE END OF THE PERIOD. THIS
TROUGH WILL BRING SOME OF THE COLDEST AIR INTO THE REGION THAT WE
HAVE EXPERIENCED IN NEARLY A MONTH. 850 MB TEMPS ARE PROGGED TO
BOTTOM OUT AROUND -15C LATE IN THE PERIOD.
AN EXTENSIVE STRATOCU DECK LINGERS ACROSS MUCH OF THE LOWER OH VALLEY
AND EASTERN KY EARLY THIS MORNING...WITH A FEW PASSING LIGHT FLURRIES
FROM TIME TO TIME PER RADAR IMAGERY. THE CLOUD COVER HAS HELD TEMPS
NEAR THE FREEZING MARK. AT OR SLIGHTLY ABOVE IN MANY VALLEY LOCATIONS
AND A DEGREE OR TWO BELOW ON THE RIDGETOPS. SAT IMAGERY TRENDS
GENERALLY INDICATE THAT THIS CLOUD DECK WILL REMAIN IN GENERALLY THE
SAME PLACE THROUGH AT LEAST 12Z. LOCALLY THE 0Z/06Z NAM RH AT 850 MB
IS DOING A DECENT JOB IN DEPICTING THE LOW CLOUDS AND CLOUD COVER FOR
TODAY LEANED TOWARD A PATTERN OF HIGHER CLOUD COVER WHERE THE 850 MB
RH WAS HIGHEST. THIS LED TO QUITE A BIT OF CLOUD COVER MUCH OF THE
DAY. SO DESPITE A START THAT WILL BE WARMER THAN MOS GUIDANCE...THE
HOURLY T CURVE TODAY WILL PROBABLY STILL BE CLOSE TO THE 3 HOURLY MOS
GUIDANCE TEMPS AFTER 15Z. THIS LED TO A SLIGHT ADJUSTMENT IN MAX T
DOWN FOR TODAY. AS FOR THE FLURRY CHANCES...PLAN TO HAVE A PREFIRST
PERIOD FOR ISOLATED TO SCATTERED FLURRIES...WITH SOME OF THIS
LINGERING AN HOUR OR TWO PAST DAWN IN THE FAR SE.
THROUGHOUT THE DAY TODAY AND INTO TONIGHT...SFC HIGH PRESSURE OVER
THE MID MS VALLEY WILL BUILD TOWARD THE REGION AND SETTLE ACROSS THE
SOUTHEAST COAST BY LATE TONIGHT. HOWEVER...A WEAK SHORTWAVE NOW
MOVING THROUGH THE MO VALLEY REGION WILL BE PASSING BY THE NORTH AND
MAY HELP TO HOLD THE STRATOCU IN PLACE TODAY. DESPITE SFC HIGH
PRESSURE DOMINATING TONIGHT...A MIX OF SOME LOW AND HIGH CLOUDS
SHOULD LEAD TO AT LEAST PARTLY CLOUD SKIES. THIS SHOULD ALSO LIMIT
MIN T FOR VALLEY LOCATIONS AND MINIMIZE ANY RIDGE/VALLEY TEMPS SPLIT.
THE SHORTWAVE NOW OVER THE ROCKIES WILL TRANSPORT SOME GULF OF MEXICO
AND PACIFIC MOISTURE NORTH INTO THE MS VALLEY LATER TODAY AND TONIGHT
AND THEN EAST INTO THE OH VALLEY AND EASTERN KY ON FRI. THIS SYSTEM
SHOULD PRECEDE A RATHER STRONG COLD FRONT ASSOCIATED WITH THE
SHORTWAVES ROTATING AROUND THE VORTEX. THIS COLD FRONT IS EXPECTED TO
MOVE ACROSS THE REGION ON FRI NIGHT. OVERALL...THIS LEADS TO A BIT OF
A COMPLEX SCENARIO WITH TEMPS ALOFT AND 1000 TO 850 MB THICKNESSES
AND 1000 TO 500 MB THICKNESSES SUPPORTING SOME SNOW WITH PRECIP
ASSOCIATED WITH THE SHORTWAVE ON FRI AFTERNOON/EVENING. THERE WILL BE
SOME INITIALLY DRY AIR TO OVERCOME AND THE RESULTANT WET BULBING
SHOULD GRADUALLY CHANGE THE PRECIP TYPE OVER TO ALL SNOW DURING FRI
EVENING. THE HIGHEST ELEVATIONS ABOVE 2500 FEET WILL PROBABLY
EXPERIENCE ALL SNOW FROM THIS ON FRI AFTERNOON/EVENING. THE DEGREE OF
SOLAR INSOLATION OR LACK THEREOF ON FRI WILL BE KEY...BUT STRONGLY
LEANED HOURLY T AND MAX T TOWARD THE 3 HOUR TEMPS FROM THE MET MOS
FOR FRI AND TRENDED THESE TEMPS DOWN SEVERAL DEGREES FROM THE
PREVIOUS FORECAST.
TOP DOWN APPROACH FROM NAM FORECAST SOUNDINGS ALSO SUPPORTS SNOW
FALLING DESPITE SFC TEMPS IN THE MID TO UPPER 30S OR SO ON FRI
AFTERNOON NORTHERN AREAS AND SUPPORTS MORE OF A RAIN TO A RAIN AND
SNOW MIX BY EARLY EVENING IN THE SOUTH. THERE WILL PROBABLY BE TWO
PEAKS IN THE PRECIP CHANCES OVERALL WITH THIS...FIRST WITH THE
SHORTWAVE FRI AFTERNOON AND EVENING AND THEN AGAIN ALONG AND BEHIND
THE COLD FRONT WITH INSTABILITY/UPSLOPE SNOW SHOWERS KICKING IN AS
850 MB TEMPS DROP OFF RATHER QUICKLY. FOR NOW...HAVE LITTLE OR NO
SNOW ACCUMULATION DURING THE DAY ON FRI...AND THIS IS GENERALLY OVER
THE NORTHERN HALF OF THE CWA...WITH NO SNOW ACCUMULATION TO THE
SOUTH...EXCEPT PERHAPS SOME LIGHT ACCUMULATIONS ABOVE 2500 FEET. THEN
AS TEMPERATURES DROP BELOW FREEZING DURING THE EVENING HOURS...HAVE
TRANSITIONED PRECIP TYPE OVER TO ALL SNOW BY THE 2Z TO 3Z PERIOD. IF
THE 0Z NAM WERE TO VERIFY THEN THIS TRANSITION WOULD BE TOO SLOW. AT
THIS POINT...FELT THAT TRANSITIONING TO PRIMARILY SNOW EARLIER THAN
THE PREVIOUS FORECAST AND HIGHER POPS BY LATE FRI INTO FRI NIGHT WAS
IN ORDER BASED ON THE MOST RECENT SUITE OF MODEL GUIDANCE.
THE UPSLOPE ISOLATED TO SCATTERED SNOW SHOWERS AND FLURRIES SHOULD LINGER
WELL INTO SAT. COLD ADVECTION DURING THE DAY SHOULD LIMIT MAX T AND
HAVE UNDERCUT GUIDANCE A BIT FOR SAT MAX T. MOST PLACES SHOULD
STRUGGLE TO GET TO FREEZING. TEMPS ON SAT COULD EVEN END UP STEADY OR
FALL. AS FOR TEMPERATURES OVER THE REMAINDER OF THE PERIOD...UNDERCUT
GUIDANCE ON FRI AS WETBULBING FROM PRECIP AND CLOUD COVER MADE THE
MOS GUIDANCE MAX T FOR FRI DOUBTFUL.
BETWEEN FRI AFTERNOON AND SAT...HAVE GENERALLY ABOUT AN INCH OF
ACCUMULATION OUTSIDE OF THE CUMBERLAND VALLEY REGION...WITH AN INCH
OR LESS IN THE CUMBERLAND VALLEY REGION. AMOUNTS AS HIGH AS 2 TO 3
INCHES COULD FALL BY LATE SAT IN THE HIGHER TERRAIN OF THE SOUTHEAST
GENERALLY ABOVE 2000 FEET. OVERALL...IF MODEL TRENDS HOLD WITH THIS
SYSTEM...THIS COULD END UP BEING AN ADVISORY EVENT. DEPENDING ON
EVENTUAL AIR AND SFC TEMPS ON FRI AFTERNOON AND EVENING THESE AMOUNTS
COULD GO UP OR DOWN A BIT.
WILL HEIGHTEN THE SNOW THREAT IN THE HWO AND WILL ALSO CONSIDER AN
SPS TO HIGHLIGHT THE MORE WINTER LIKE WEATHER EXPECTED TO START THE
WEEKEND.
.LONG TERM.../SATURDAY NIGHT THROUGH WEDNESDAY/
ACTIVE PATTERN TAKING SHAPE THROUGH THE LONG TERM PORTION OF THE
FORECAST AS MODELS POINT TOWARDS A SPLIT FLOW DEVELOPING OVER THE
WRN U.S. TO START THE PERIOD...WITH RIDGING OVER THE HEART OF THE
CONUS AND THE DEPARTING TROF LIFTING THROUGH THE NORTHEAST. AN
EXPANSE OF SFC HIGH PRESSURE OVER THE PLAINS WILL BE IN THE PROCESS
OF BUILDING INTO THE MID MS AND OHIO VALLEYS ON SATURDAY NIGHT INTO
SUNDAY BEHIND THE DEPARTING SYSTEM...BRINGING DRIER WEATHER TO THE
AREA...ALBEIT WITH ANOTHER ROUND OF SOME OF THE COLDEST TEMPS OF THE
WINTER THUS FAR AS THE AO FORECAST CONTINUES TO TREND NEGATIVE
THROUGH THE CURRENT 14 DAY OUTLOOK PERIOD.
HIGH PRESSURE AND RIDGING ALOFT LOOKS TO EASE OFF TOWARDS THE
CAROLINAS ON MONDAY INVOKING A RETURN FLOW OF GOMEX MOISTURE AHEAD
OF THE FIRST IN A SERIES OF SHORT WAVES DEPICTED IN THE MEDIUM RANGE
MODELS AS DEVELOPING IN THE SRN STREAM OVER THE GREAT BASIN BEFORE
EJECTING OUT OF THE ROCKIES AND ACROSS THE PLAINS. OPERATIONAL
GUIDANCE CARRIES THE SFC REFLECTION INTO THE LOWER MS VALLEY MONDAY
NIGHT AS A SECONDARY SFC LOW DEVELOPS OVER THE NRN PLAINS AND BEGINS
TREKKING TOWARDS THE GREAT LAKES. THE COMBINED RESULT SPREADS PRECIP
OVER THE OHIO VALLEY AND INTO ERN KY FROM MONDAY NIGHT THROUGH
TUESDAY BEFORE TAPERING OFF TUESDAY NIGHT. THE GFS REMAINS A TAD
FASTER THAN THE ECMWF AT THIS POINT BUT BOTH OPERATIONAL MODELS
SUPPORT SHOWERS MOVING INTO THE AREA BY MONDAY NIGHT. GIVEN THE
PATTERN AND TEMPERATURE PROFILES...HAVE CONSIDERED SNOW FOR THE
OVERNIGHT HOURS ALTHOUGH SFC TEMPS LOOK TO BE JUST A LITTLE TOO WARM
AT THIS POINT FOR ANY SIGNIFICANT ACCUMULATIONS. HOWEVER...THE
09.00Z GFS FCST SOUNDINGS DO DEPICT A BRIEF WINDOW AROUND TUESDAY
MORNING THAT WOULD SUPPORT FREEZING RAIN. THIS FAR OUT...HAVE HEDGED
WITH A CHANCE OF RAIN OR SNOW MONDAY NIGHT BEFORE LINGERING SHOWERS
ON TUESDAY TRANSITION BACK OVER TO RAIN.
MODELS BRING FLEETING HIGH PRESSURE UP THE OHIO VALLEY AROUND THE
MIDDLE OF THE WEEK TO END THE PERIOD BUT THE NEXT SYSTEM IS ALREADY
APPEARING ON THE HORIZON WITH THE GFS AGAIN TAKING THE LEAD AND
OUTPACING THE EURO BY ABOUT A HALF A DAY...WHICH MAY JUST PAN OUT
GIVEN THE PROGRESSIVE FLOW. WILL KEEP CHANCE POPS FROM THE EXTENDED
INITIALIZATION TO CLOSE OUT THE PERIOD FOR NOW AND HOPE FOR A BETTER
CONSENSUS IN THE NEXT ITERATIONS.
&&
.AVIATION.../18Z TO 18Z/...UPDATED
CEILINGS REMAIN NEAR THE MVFR/VFR BREAK POINT AS LOW LEVEL MOISTURE
REMAINS LOCKED IN ACROSS EASTERN KENTUCKY. BASED ON LATEST TRENDS
WILL FORECAST MVFR CEILINGS FOR THE START OF THE FORECAST
PERIOD....TRNEDING TO VFR AS THE CLOUD DECK GRADUALLY LIFTS. RAIN AND
SNOW WILL OVERSPREAD THE AREA LATE FRIDAY AFTERNOON AS A WAVE OF LOW
PRESSURE MOVES OUT OF THE SOUTHERN PLAINS AND A COLD FRONT DROPS
TOWARDS THE AREA. CONDITIONS WILL DETERIORATE LATE FRIDAY WITH IFR
OR LOWER CONDITIONS EXPECTED WITH SNOW FRIDAY NIGHT .
&&
.JKL WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...JP/SBH
LONG TERM....MB
AVIATION...SBH
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
636 PM EST FRI FEB 10 2012
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 423 PM EST FRI FEB 10 2012
WV IMAGERY AND RUC ANALYSIS INDICATED CENTER OF THE POLAR VORTEX
EAST OF HUDSON BAY WITH A MID/UPPER LEVEL TROUGH AIX TO THE
SOUTHWEST THROUGH ERN LAKE SUPERIOR INTO CTNRL WI. AT THE SFC...A
1046 MB ARCTIC HIGH WAS LOCATED OVER SASK WITH A RIDGE EXTENDING
INTO NRN ONTARIO AND THROUGH THE PLAINS. NNW WINDS IN THE VERY COLD
AIRMASS SUPPORTED LES FOR LOCATIONS FAVORED BY NRLY WINDS.
HOWEVER...LES WAS DIMINISHING AND BANDS WERE SHIFTING WITH THE ACYC
FLOW...BACKING WINDS AND VERY DRY AIR WELL MIXED LOW LEVEL AIR
UPSTREAM WITH SFC DEWPOINTS TO NEAR -20F.
TONIGHT...WITH 850MB TEMPS AROUND -20C...LES WILL BE ONGOING IN
AREAS FAVORED BY NW WINDS. THE DRY AIR AND LOW INVERSION AOB 3KFT
WILL KEEP LES LIGHT INITIALLY. HOWEVER...WITH THE DENDRITIC SNOW
GROWTH TEMP ZONE (DGZ) FIRMLY IN THE CONVECTIVE LAYER...SHOULD STILL
BE ABLE TO GET A FEW INCHES OF FLUFFY SNOW MAINLY OVER THE NE FCST
AREA WHERE ENOUGH MOISTENING CAN OCCUR DESPITE THE DRY AIR.
WINDS OVER FAR SW UPPER MI MAY BACK SUFFICIENTLY TO CUT OVERWATER
TRAJECTORIES ENOUGH TO ALLOW FOR SOME CLEARING. EXPECT TEMPS THERE
TO FALL INTO THE SINGLE DIGITS BLO ZERO. ELSEWHERE...TEMPS ARE
EXPECTED TO REMAIN IN THE SINGLE DIGITS AND LOWER TEENS AS SFC-925MB
WINDS GENERALLY MAINTAIN SOME MODIFICATION OFF OF LAKE SUPERIOR.
SATURDAY...EXPECT LES INTENSITY TO INCREASE BY SAT AFTERNOON AS
850-700 MB MOISTURE INCREASES IN A DEVELOPING WAA PATTERN. WITH
850MB TEMPS MODERATING THROUGH THE DAY THE DGZ WILL CLIMB...BECOMING
MORE FAVORABLY POSITIONED IN THE CONVECTIVE LAYER/UPWARD MOTION
REGION. LONGER FETCH AND LONGER DURATION OF MORE FAVORABLE LES
PARAMETERS SUGGEST BEST SNOW ACCUMULATIONS WILL BE OVER THE NE FCST
AREA...WHERE AMOUNTS IN THE 2 TO 4 INCH RANGE ARE EXPECTED.
OVER WRN LAKE SUPERIOR...FLOW IS MORE WESTERLY AND ENHANCED
CONVERGENCE COULD DEVELOP BTWN THE PORCUPINE MTNS AND HOUGHTON. THIS
AREA OVER THE WRN CWA COULD ALSO SEE INCREASE IN LES.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 423 PM EST FRI FEB 10 2012
CURRENT PUSH OF ARCTIC AIR INTO THE UPPER LAKES WILL BE SHORT LIVED
AS POLAR VORTEX E OF HUDSON BAY RETREATS/REFORMS BACK TOWARD THE
POLE NEXT WEEK. THE RETREAT OF THE NRN STREAM AND A DISTINCT SPLIT
FLOW REGIME NEXT WEEK WILL BRING A RETURN OF THIS WINTERS PREVAILING
THEME OF ABOVE NORMAL TEMPS. WHETHER OR NOT THIS SPLIT FLOW LEADS TO
ANY SRN STREAM SYSTEMS REACHING THE UPPER GREAT LAKES REMAINS TO BE
SEEN. AT THIS POINT...IT STILL APPEARS THAT THE OVERALL DRY PATTERN
WILL PERSIST NEXT WEEK THOUGH THERE ARE MUCH INCREASED UNCERTAINTIES
IN POSSIBLE STREAM INTERACTIONS THAT MAY LEAD TO SOME STORMINESS IN
THE GREAT LAKES LATE IN THE WEEK.
BEGINNING SAT NIGHT...TROF ASSOCIATED WITH POLAR VORTEX E OF HUDSON
BAY WILL BEGIN SHIFTING E...RESULTING IN THE BEGINNINGS OF A WAA
REGIME WHICH WILL CONTINUE THRU SUN. LES WILL BE ONGOING SAT EVENING
OVER THE E AT LOCATIONS FAVORED BY A WNW/NW WIND OFF LAKE SUPERIOR.
HOWEVER...INVERSION QUICKLY SETTLES DOWN TO 4KFT OR LWR LATE EVENING
AND OVERNIGHT. ALSO...WAA BEGINS TO SHIFT DENDRITIC SNOW GROWTH TEMP
ZONE (DGZ) UP ABOVE BEST UPWARD MOTION. IN GENERAL...MIGHT SEE
ANOTHER 1-2 MAYBE 3 INCHES OF SNOW OVER THE NE FCST AREA SAT NIGHT.
OUT W...INVERSION WILL ALREADY BE SETTLING TO 3KFT OR LWR EARLY IN
THE EVENING WITH DGZ ABOVE THE INVERSION. GIVEN THE LOW INVERSION
AND MODERATING AIRMASS...THERE MAY NOT BE MUCH LEFT OTHER THAN
FLURRIES SAT EVENING WITH GRADUAL CLEARING THEN FOLLOWING DURING THE
NIGHT FROM THE W. FROM AN ISENTROPIC STANDPOINT...CONDENSATION PRES
DEFICITS ARE QUITE HIGH SAT NIGHT IN DEVELOPING WAA REGIME...SO
THERE SHOULDN`T BE MUCH IN THE WAY OF WAA CLOUDINESS. ALTHOUGH SKIES
WILL BE CLEARING FROM THE W...MAY NOT BE ABLE TO DECOUPLE COMPLETELY
AS A STRONG PRESSURE GRADIENT STILL EXISTS BETWEEN A 1040MB HIGH
SINKING INTO THE CENTRAL PLAINS AND A 1008MB TROUGH OVER WESTERN
HUDSON BAY/FAR NRN ONTARIO. MINS SHOULD END UP NEAR ZERO IN THE
TRADITIONAL COLD SPOTS OVER THE INTERIOR W HALF...RANGING UP TO THE
TEENS E NEAR LAKE SUPERIOR.
LINGERING LIGHT LES OVER THE NE FCST AREA WILL END SUN AS INVERSION
CONTINUES TO LWR AND MORE IMPORTANTLY TEMPS AT INVERSION BASE RISE
ABOVE -10C. AWAY FROM DIMINISHING LIGHT LES E...SUN SHOULD TURN OUT
TO BE A MAINLY SUNNY DAY UNDER A DEEP DRY AIR MASS. DRY AIR MASS AND
SUNSHINE WORKING ON THE LWR ALBEDO FORESTED LANDSCAPE OF UPPER MI
WILL ASSIST THE WARM UP...BUT STRONG INVERSION WILL HOLD BACK THE
WARMING POTENTIAL OVER WHAT IT COULD BE. FCST SOUNDINGS SUGGEST
MIXING TO 900MB...BUT THAT MIGHT BE A LITTLE OPTIMISTIC. MID/UPPER
20S SHOULD BE THE RULE.
POLAR VORTEX WILL BE RETREATING MON WITH UPSTREAM SPLIT FLOW
ADVANCING INTO THE CNTRL CONUS. IN THE SPLIT...MODEL GUIDANCE
CONTINUES TO INDICATE A SRN STREAM SHORTWAVE MOVING INTO THE MID
MISSISSIPPI VALLEY LATE MON. THERE HASN`T BEEN MUCH MODEL SPREAD
WITH THIS SYSTEM IN RECENT RUNS...AND LATEST ROUND OF GUIDANCE
MAINTAINS THE IDEA THAT THE BULK OF ASSOCIATED PCPN WILL PASS S OF
UPPER MI. SEE NO REASON TO STRAY FROM THAT SCENARIO RIGHT NOW.
SO...CLEAR SKIES SUN NIGHT WILL GIVE WAY TO A SLOW INCREASE IN
HIGH/MID CLOUDS FROM THE SW MON. MAINTAINED SLIGHT CHC POPS ACROSS
THE FAR S/SE MON NIGHT AS THE NRN FRINGE OF PCPN MAY BRUSH THAT
AREA.
TUE THRU FRI...UNDER SPLIT FLOW WITH MORE PROGRESSIVE NRN STREAM...
ARCTIC AIR WILL BE BOTTLED UP WELL TO THE N DURING THE MIDDLE AND
END OF NEXT WEEK. BENIGN/DRY WEATHER SHOULD CONTINUE TUE/WED. EVEN
LES WON`T BE A CONCERN WITH CONSENSUS 850MB TEMPS WARMER THAN -8C.
HEADING INTO THU/FRI...SOME RECENT GFS RUNS HAVE SUGGESTED POSSIBLE
STREAM INTERACTIONS SOMEWHERE FROM THE MISSISSIPPI VALLEY EASTWARD
THAT COULD LEAD TO A STORM SYSTEM IN THE GREAT LAKES AREA. TODAYS
12Z ECMWF RUN IS NOW BEGINNING TO SUGGEST THAT AS WELL. AS ALWAYS...
THERE IS LOW CONFIDENCE IN STREAM PHASING...AND IT GOES WITHOUT
SAYING THAT THERE IS TREMENDOUS UNCERTAINTY IN ANY TYPE OF
INTERACTION THAT FAR OUT IN A MODEL RUN. WILL BE SOMETHING TO
MONITOR IN THE COMING DAYS...BUT FOR NOW...FAVORED THE MORE
DISTINCT...SEPARATED FLOW REPRESENTED BY PREVIOUS ECMWF RUNS. AS A
RESULT...MAINTAINED A DRY FCST FOR THU/FRI THOUGH THERE COULD BE A
LITTLE -SN AT SOME POINT. AIR MASS REMAINS WARM ENOUGH TO PRECLUDE
ANY MENTION OF LES.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 636 PM EST FRI FEB 10 2012
LES IS EXPECTED TO REDEVELOP AT CMX AND IWD OVERNIGHT AS MOISTURE
INCREASES AGAIN WITH NW FLOW. HOWEVER...MAINLY MVFR CONDITIONS WILL
PREVAIL WITH ONLY BRIEF PERIODS OF IFR POSSIBLE. AT SAW...ANY LES
TONIGHT WILL BE VERY LIGHT AND SHOULD NOT REDUCE VISIBILITIES BELOW
6SM.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 423 PM EST FRI FEB 10 2012
NNW WINDS TO 30KT WILL PERSIST WITH AMPLE INSTABILITY IN THE ARCTIC
AIRMASS MOVING OVER THE REGION. NW WINDS APPROACHING GALES TO 35 KT
ARE ALSO POSSIBLE SAT AFTERNOON INTO SAT EVENING OVER ERN LAKE
SUPERIOR. EXPECT HEAVY FREEZING SPRAY ACROSS THE ENTIRE LAKE TONIGHT
THROUGH SAT NIGHT WITH THE STRONG WINDS AND WAVE ACTION. LOOK FOR
HEAVY FREEZING SPRAY TO END ON SUNDAY AS THE AIRMASS WARMS AND WINDS
GRADUALLY DIMINISH. CONDITIONS WILL QUIET DOWN FOR THE EARLY PART OF
THE WORK WEEK AS A HIGH PRES RIDGE MOVES OVER THE UPPER GREAT LAKES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST /6 AM CST/ SUNDAY
FOR LSZ162-240>251-263>267.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...ROLFSON
AVIATION...TITUS
MARINE...JLB
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
241 PM CST THU FEB 9 2012
.DISCUSSION...
ARCTIC COLD FRONT WITH DECENT PRESSURE FALLS OVER NORTH DAKOTA DROPPING
SOUTH ABOUT AS FORECAST. NOT TOO MANY SITES REPORTING SNOW BUT
A COUPLE OF SITES IN NW ONT WERE DOWN TO AROUND 2SM. THE LATEST RUC
AND THE NAM TO A LESSER EXTENT DO FORECAST AN INCREASE IN QG VERT
VEL AND FGEN TO OUR NE AS THE FRONT DROPS SOUTH WILL INCREASE POPS
TO A CHANCE CATEGORY OVER IN WEST CENTRAL WI TO ACCOUNT FOR THIS.
WITH THE FRONT MOVING DOWN WILL GO WITH A MODEL WEIGHTED DIURNAL
TEMP TREND OVERNIGHT. SOME GUSTY WINDS FOR A TIME WITH THE COLD
ADVECTION TOO. NOT MUCH TEMP CHANGE FROM THE MORNING IN THE SE
FOR FRIDAY HIGHS.
FEEL THAT THE NAM IS OVERDOING THE LOW LEVEL MOISTURE FIELDS ON
FRIDAY WITH THE GFS AND RUC LOOKING BETTER AT LEAST IN THE MN
PORTION OF THE AREA. COLD ADVECTION OS THERE...BUT WE LOOSE THE
CYCLONIC CURVATURE IN THE AFTERNOON. LOOKS LIKE A COLD LOOKS
COLD FRIDAY NIGHT UNDER CLEAR SKIES BUT WITH A PRES GRADIENT
CONTINUING. MOST SITES LIKELY BELOW ZERO BUT THIS REGIME IS NOT
AS COLD AS THE MID JANUARY BLAST.
MODERATION BEGINS LATE IN THE WEEKEND AND EARLY NEXT WEEK WITH A
RETURN TO A MORE WESTERLY FLOW BUT SOMEWHAT SPLIT WITH MORE
BLOCKING AROUND THE NORTHERN HEMISPHERE. WE STILL HAVE A CHANCE OF
SNOW FOR SOUTHERN AREAS MONDAY AND MONDAY NIGHT WITH A CENTRAL
PLAINS TROUGH. PRECIP PROBS BETTER IN THE CENTRAL PLAINS THOUGH.
THERE HAD BEEN SOME CHANCE AGAIN LATER WEDNESDAY AND THURSDAY BUT
THE 12Z ECMWF...AND GFS ENSEMBLE POPS ARE NOT SHOWING MUCH. THE
12Z GFS IS THE ONLY MODEL TO SHOW SOME A CHANCE BUT THIS A LITTLE
CLOSE BEHIND THE MONDAY SYSTEM IN A SPLIT FLOW. TEMPS BACK TO NEAR
OR ABOVE NORMAL NEXT WEEK.
&&
.AVIATION.../18Z TAF ISSUANCE/
ARCTIC FRONT STILL LOOKS ON TRACK TO DROP SOUTH THROUGH THE AREA
THIS EVENING... BRINGING A PERIOD OF SOME MVFR CEILINGS WITH IT AS
IT DOES SO. GUSTY NORTH-NORTHWEST WINDS WILL ALSO DEVELOP BEHIND
THE FRONT FOR A TIME. BOTH THE GUSTY WINDS AND MVFR CEILINGS
SHOULD DEPART FAIRLY QUICKLY DURING THE DAY ON FRIDAY AS DRIER AIR
AND ANTICYCLONIC FLOW ASSOCIATED WITH THE SURFACE RIDGE WORK INTO
THE AREA. THE NAM APPEARS OVERLY PESSIMISTIC WITH ITS LOW LEVEL
RH/CLOUD FORECASTS... KEEPING BOUNDARY LAYER DEWPOINTS TOO HIGH IN
THE WAKE OF THE FRONT AND THEREBY CONTINUING TO PRODUCE SOME
CONVECTIVE COLD AIR STRATOCU FOR A GOOD 24 HOURS AFTER IT APPEARS
LIKELY BASED ON UPSTREAM OBS... THE GFS... AND OTHER GUIDANCE.
KEPT SOME CEILINGS AROUND A BIT LONGER THAN PREVIOUSLY
INDICATED... MAINLY IN LINE WITH GFS FORECAST MOISTURE PROFILES.
KMSP... TAF REFLECTS GENERAL FORECAST THINKING... ALTHOUGH THERE
IS SOME UNCERTAINTY IN HOW LONG MVFR CEILINGS WILL LINGER INTO THE
DAY ON FRIDAY. THINK THERE COULD BE AN INITIAL BATCH OF CEILINGS
AROUND 2K FT AGL... THEN A CHANGE TO SCT FOR A TIME BEFORE SOME
REDEVELOPMENT OF CEILINGS CLOSER TO 3K FT AGL AFTER 12Z. BUT...
FOR NOW... KEPT THINGS SIMPLE AND JUST INCLUDED A LONGER PERIOD OF
CEILINGS WITH IMPROVEMENT OVER TIME. SOME WIND GUSTS HIGHER THAN
SUGGESTED COULD ALSO OCCUR TONIGHT AFTER FROPA DEPENDING UPON HOW
DEEPLY WE MIX IN THE POST FRONTAL COLD ADVECTION AND PRESSURE RISE AREA.
//OUTLOOK FOR KMSP FOR FRIDAY NIGHT THROUGH TUESDAY...
FRIDAY NIGHT THROUGH SUNDAY...VFR CONDITIONS EXPECTED.
SUNDAY NIGHT...MVFR CEILINGS POSSIBLE LATE.
MONDAY AND MONDAY NIGHT...MVFR CEILINGS EXPECTED.
TUESDAY...MVFR CEILINGS POSSIBLE EARLY.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
JPR/JVM
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1123 AM CST Thu Feb 9 2012
...UPDATED AVIATION DISCUSSION...
.DISCUSSION...
Widespread stratus once again in place early this morning, which has
held overnight temperatures on the warm side for locations beneath
this cloud deck. Outside of the stratus, temperatures have dropped
quite a bit with lows currently in the teens across northeast Missouri.
Similar to yesterday, believe the stratus will be slow to erode today
which is supported by the latest RUC condensation deficits and
various BUFR soundings. However, overall model performance has been
poor in handling the low level moisture over the past couple of days
so confidence is necessarily high.
Surface ridge will shift into the lower to mid Mississippi valley
today allowing low level winds to swing around to the southwest.
This will advect warmer temperatures into the area although lighter
speeds will prevent significant warming. Mixing to around H9-H85
should help break up clouds to some degree. However, given the
expectation of prolonged, at least broken cloud cover, knocked a few
degrees off of temperatures for this afternoon.
Advertised Hudson Bay low will settle southward through the end of
the week with pronounced short wave energy diving southward into the
central CONUS. Given the meridional nature of the upper height
pattern by the beginning of the weekend in response to amplified
ridging across the western US/Canada, expect a decent chunk of arctic
air to dislodge and plunge southward into the region. Expect the sfc
baroclinic boundary to slide through the area Friday morning with CAA
taking shape thereafter. The main story through the weekend will then
be the cold temperatures as most locations will not see readings
above the freezing mark for several days.
Deep eastern US upper troughing establishes by the middle of the
weekend with upper short wave ridging sliding overhead by Sunday. A
more progressive upper flow pattern then establishes across the
CONUS through the end of the weekend and through the first half of
next week. Models continue to be in good agreement with the timing
of the next progressive short wave trough to affect the area by
Sunday night and Monday. Given the run to run consistency, felt
comfortable continuing to raise POPS for this time period. There
still appears to be a decent shot at accumulating snowfall across
most of the forecast area as this system swings through. The main
limiting factor at this point appears to be the speed at which the
system progresses through the area. Nevertheless, many areas may
finally be in store for the first decent snowfall of the season.
There looks to be a short reprieve on Tuesday before the next system
in the progressive pattern affects the area by Wednesday. Models
have not displayed as good run to run consistency during this period
and will remain close to the consensus numbers to account.
Deroche
&&
.AVIATION...
For the 18Z TAF: Will go with a more pessimistic forecast than in
previous TAF as stratus should remain planted across the terminals.
Ceilings are expected to bounce between VFR and MVFR for much of the
first 12 hours of the taf as westerly flow continues over snowpack to
the west and northwest.
For tonight, arctic cold front will enter the CWA after 06z tonight,
with winds gradually switching to the northwest and then north by
12z. Ceilings should lower once again as the front approaches and may
lower more significantly behind the front. Will introduce mvfr CIGS
before daybreak, with SREF probabilities indicating the potential for
IFR cigs by 12z. Clouds should clear substantially late Friday
morning.
Dux
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
WFO EAX
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
517 AM CST Thu Feb 9 2012
...UPDATED AVIATION DISCUSSION...
.DISCUSSION...
Widespread stratus once again in place early this morning, which has
held overnight temperatures on the warm side for locations beneath
this cloud deck. Outside of the stratus, temperatures have dropped
quite a bit with lows currently in the teens across northeast Missouri.
Similar to yesterday, believe the stratus will be slow to erode today
which is supported by the latest RUC condensation deficits and
various BUFR soundings. However, overall model performance has been
poor in handling the low level moisture over the past couple of days
so confidence is necessarily high.
Surface ridge will shift into the lower to mid Mississippi valley
today allowing low level winds to swing around to the southwest.
This will advect warmer temperatures into the area although lighter
speeds will prevent significant warming. Mixing to around H9-H85
should help break up clouds to some degree. However, given the
expectation of prolonged, at least broken cloud cover, knocked a few
degrees off of temperatures for this afternoon.
Advertised Hudson Bay low will settle southward through the end of
the week with pronounced short wave energy diving southward into the
central CONUS. Given the meridional nature of the upper height
pattern by the beginning of the weekend in response to amplified
ridging across the western US/Canada, expect a decent chunk of arctic
air to dislodge and plunge southward into the region. Expect the sfc
baroclinic boundary to slide through the area Friday morning with CAA
taking shape thereafter. The main story through the weekend will then
be the cold temperatures as most locations will not see readings
above the freezing mark for several days.
Deep eastern US upper troughing establishes by the middle of the
weekend with upper short wave ridging sliding overhead by Sunday. A
more progressive upper flow pattern then establishes across the
CONUS through the end of the weekend and through the first half of
next week. Models continue to be in good agreement with the timing
of the next progressive short wave trough to affect the area by
Sunday night and Monday. Given the run to run consistency, felt
comfortable continuing to raise POPS for this time period. There
still appears to be a decent shot at accumulating snowfall across
most of the forecast area as this system swings through. The main
limiting factor at this point appears to be the speed at which the
system progresses through the area. Nevertheless, many areas may
finally be in store for the first decent snowfall of the season.
There looks to be a short reprieve on Tuesday before the next system
in the progressive pattern affects the area by Wednesday. Models
have not displayed as good run to run consistency during this period
and will remain close to the consensus numbers to account.
Deroche
&&
.AVIATION...
For the 12Z TAFS...ceilings will be the main challenge for the first
half of the valid period. Current ceilings around 3k-3.5 ft should
lift to around 5k ft by this afternoon and then begin to lift further
and scatter out this evening. Winds are expected to be light through
most of the valid period but will veer through the day as surface
high pressure moves east of the area. A front is expected to begin
moving through the area veer late in the valid period which will
switch winds around to the northwest by 09-12Z Friday. Winds will
also increase behind the front and lower level clouds should fill in
an hour or two behind the front as well.
CDB
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
WFO EAX
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
311 AM CST Thu Feb 9 2012
.DISCUSSION...
Widespread stratus once again in place early this morning, which has
held overnight temperatures on the warm side for locations beneath
this cloud deck. Outside of the stratus, temperatures have dropped
quite a bit with lows currently in the teens across northeast Missouri.
Similar to yesterday, believe the stratus will be slow to erode today
which is supported by the latest RUC condensation deficits and
various BUFR soundings. However, overall model performance has been
poor in handling the low level moisture over the past couple of days
so confidence is necessarily high.
Surface ridge will shift into the lower to mid Mississippi valley
today allowing low level winds to swing around to the southwest.
This will advect warmer temperatures into the area although lighter
speeds will prevent significant warming. Mixing to around H9-H85
should help break up clouds to some degree. However, given the
expectation of prolonged, at least broken cloud cover, knocked a few
degrees off of temperatures for this afternoon.
Advertised Hudson Bay low will settle southward through the end of
the week with pronounced short wave energy diving southward into the
central CONUS. Given the meridional nature of the upper height
pattern by the beginning of the weekend in response to amplified
ridging across the western US/Canada, expect a decent chunk of arctic
air to dislodge and plunge southward into the region. Expect the sfc
baroclinic boundary to slide through the area Friday morning with CAA
taking shape thereafter. The main story through the weekend will then
be the cold temperatures as most locations will not see readings
above the freezing mark for several days.
Deep eastern US upper troughing establishes by the middle of the
weekend with upper short wave ridging sliding overhead by Sunday. A
more progressive upper flow pattern then establishes across the
CONUS through the end of the weekend and through the first half of
next week. Models continue to be in good agreement with the timing
of the next progressive short wave trough to affect the area by
Sunday night and Monday. Given the run to run consistency, felt
comfortable continuing to raise POPS for this time period. There
still appears to be a decent shot at accumulating snowfall across
most of the forecast area as this system swings through. The main
limiting factor at this point appears to be the speed at which the
system progresses through the area. Nevertheless, many areas may
finally be in store for the first decent snowfall of the season.
There looks to be a short reprieve on Tuesday before the next system
in the progressive pattern affects the area by Wednesday. Models
have not displayed as good run to run consistency during this period
and will remain close to the consensus numbers to account.
Deroche
&&
.AVIATION...
VFR to maybe high end MVFR ceilings will continue through the
majority of the 06Z TAF cycle as flow begins to return on the
backside of surface high pressure, sloshing upslope stratus back
into the area. Have pushed back clearing to around sunset tomorrow
evening.
Winds will be light east through much of tonight, becoming south
then southwest at around 6-8 knots for most of the day Thursday.
Bookbinder
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
WFO EAX
AREA FORECAST DISCUSSION
NWS BUFFALO NY
708 PM EST FRI FEB 10 2012
.SYNOPSIS...
A COLD FRONT WILL APPROACH FROM THE NORTH THIS EVENING...THEN DROP
ACROSS THE REGION LATE TONIGHT. SCATTERED SNOW SHOWERS THROUGH THIS
EVENING WILL BECOME MORE WIDESPREAD LATE TONIGHT INTO SATURDAY. THIS
WILL BRING IN COLDER TEMPERATURES AND SOME SNOW ACCUMULATION.
ANOTHER COLD FRONT WILL APPROACH FROM THE NORTH...WHICH WILL LIKELY
BRING A ROUND OF LAKE SNOWS LATE SATURDAY NIGHT INTO SUNDAY.
&&
.NEAR TERM /THROUGH SATURDAY/...
OUR WEATHER WILL CONTINUE TO KEY ON THE PROGRESSION OF AN
APPROACHING FRONTAL BOUNDARY. OUTSIDE OF SOME LAKE EFFECT EAST OF
LAKE ONTARIO...EXPECT GENERALLY LIGHT AND PATCHY SNOW ACCUMULATION
AHEAD OF THE FRONT.
THE 12Z MODEL RUNS CONTINUE TO SLOW THE PROGRESSION OF THE COLD
FRONT. THE UPPER LEVEL TROF DRIVING THE FRONT IS FORECAST TO
SHARPEN...WHICH EFFECTIVELY SLOWS THE PROGRESSION OF THE FRONT...AND
ALSO AIDS IN THE DEVELOPMENT OF A WEAK SURFACE LOW ALONG THE
BOUNDARY. THE 12Z NAM/GFS/RGEM ARE ALL SUPPORTING THIS SLOWER
PROGRESSION...WHICH HAS BEEN THE TREND FOR SEVERAL RUNS NOW.
THIS WILL HAVE A FAIRLY SIGNIFICANT IMPACT ON THE FORECAST...SINCE
THE SLOWER PROGRESSION OF THE FRONT WILL PUSH BACK START TIME OF THE
STEADY SNOW UNTIL LATE TONIGHT. ACROSS NORTHWESTERN NEW YORK FROM
BUFFALO-ROCHESTER NORTHWARD...EXPECT THE STEADIEST SNOW FROM 600 AM
THROUGH NOON...SLIGHTLY LATER TO THE SOUTH OF THIS.
GENERALLY ACCEPT THE CONSENSUS QPF FROM THE 12Z NAM12/RGEM...THOUGH
SOME UPSLOPE ENHANCEMENT MAY OCCUR BEYOND MODEL QPF FORECASTS. THERE
SHOULD BE A PERIOD OF SNOW BOTH ALONG THE FRONT...AND BEHIND THE
FRONT DUE TO LAKE ENHANCEMENT AND UPSLOPING.
EXPECT THE MOST SNOW TO FALL ACROSS WESTERN PORTIONS OF THE SOUTHERN
TIER...WHERE THE SURFACE LOW...UPPER LEVEL TROF...AND UPSLOPING
SHOULD ALL COME TOGETHER TO BRING SEVERAL HOURS OF MODERATE SNOWS.
EXPECTING 3 TO 5 INCHES IN THE FAVORABLE UPSLOPE RIDGES...AND BASED
ON THIS WILL ISSUE A WINTER WEATHER ADVISORY FOR
CHAUTAUQUA/CATTARAUGUS COUNTIES. SNOW AMOUNTS WILL BE LESS
ELSEWHERE...THOUGH GENERALLY EXPECT 2 OR 3 INCHES IN BUFFALO
METRO/BOSTON HILLS/NIAGARA FRONTIER. AMOUNTS TO THE EAST SHOULD BE
LESS...FURTHER FROM THE UPPER TROF...WITH GENERALLY 2 INCHES OR LESS
EXPECTED.
THE EAST TO WEST ORIENTATION OF THE FRONT WILL ALLOW IT TO DROP
ACROSS THE NORTH COUNTRY EARLIER...WITH THE FRONT LIKELY TO SLOWLY
DROP ACROSS SHORTLY AFTER MIDNIGHT. WHILE THIS REGION IS FURTHER
REMOVED FROM THE UPPER LOW AND THE DEEPER MOISTURE...THERE WILL BE A
PERIOD FAVORABLE FOR LAKE ENHANCEMENT IMMEDIATELY AHEAD OF THE
FRONT. RADAR TRENDS AND THE HRRR SUPPORT DEVELOPMENT OF FAIRLY
WIDESPREAD LAKE ENHANCED SNOW SHOWERS AHEAD OF THE FRONT...DESPITE
MINIMAL QPF FROM THE NAM/RGEM. HERE...MOST OF THE SNOW SHOULD FALL
LATE AFTERNOON AND THIS EVENING...AHEAD OF THE FRONT...WHERE 1 TO 3
INCHES IS POSSIBLE ON THE TUG HILL AND IN JEFFERSON COUNTY.
THE SLOWER PROGRESSION OF THE FRONT WILL ALSO HAVE A BIG IMPACT ON
TEMPERATURES. WHILE THE FRONT WILL STILL PASS THROUGH THE NORTH
COUNTRY...IT IS QUESTIONABLE IF THE COLD AIR WILL MAKE IT INTO
BUFFALO BY DAYBREAK. THE RESULT IS LOW TEMPERATURES WHICH ARE QUITE
A BIT WARMER ALONG THE I-90 CORRIDOR. THIS SAID...THE FRONT WILL
STILL CROSS...AND TEMPERATURES WILL DROP BEHIND THE FRONT SATURDAY
MORNING. SATURDAY WILL STILL BE A COLD DAY...WITH MID-DAY
TEMPERATURES IN THE UPPER TEENS TO LOWER 20S...EVEN IF THE MORNING
STARTS OFF A BIT WARMER THAN THIS.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/...
AN ACTIVE PERIOD SATURDAY NIGHT AND INTO SUNDAY AS LAKE EFFECT SNOW
IS EXPECTED...ENHANCED BY A SOUTHWARD DROPPING ARCTIC FRONT SUNDAY.
SATURDAY NIGHT THE AXIS OF AN UPPER LEVEL TROUGH WILL BE CROSSING
THE REGION...WITH WINDS THROUGH THE BOUNDARY LAYER EXHIBITING TOO
MUCH SHEER...AND LIMITED BOUNDARY LAYER MOISTURE FOR ANY LAKE EFFECT
TO BE ONGOING. SYNOPTIC SNOW WILL BE ENDING ACROSS THE SOUTHERN TIER
EARLY SATURDAY NIGHT WITH LITTLE FURTHER SNOW ACCUMULATION.
TEMPERATURES ALOFT AT 850 HPA WILL BE PLENTY COLD ENOUGH TO SUPPORT
LAKE EFFECT SNOW THOUGH LIFT REMAINS MARGINAL AND MOISTURE IN THE
GOOD SNOW CRYSTAL GROWTH ZONE REMAINS LIMITED TO START.
AS THE NIGHT PROGRESS MOISTURE IN THE LOWER LEVELS INCREASES AND
LAKE INDUCED EQUILIBRIUM LEVELS INCREASE ALONG WITH A DECREASE IN
WIND SHEAR. THIS WILL FAVOR THE FORMATION OF LAKE EFFECT SNOW
BANDS...WITH AN UPSTREAM CONNECTION TO LAKE HURON AND GEORGIAN BAY
LIKELY. THE GREATEST LIFT WILL BE CENTERED OVER LAKE ONTARIO AND
INLAND TOWARDS THE GENESEE VALLEY AND WITH AN UPSTREAM CONNECTION TO
GEORGIAN BAY HERE IS WHERE THE HEAVIEST SNOW BAND IS EXPECTED.
WITH THE UPPER LEVEL WINDS A LITTLE MORE BACKED IN THE LONG WAVE
TROUGH THE FOCUS OF THE LAKE EFFECT SNOW SATURDAY NIGHT IS EXPECTED
TO BE CENTERED MORE FROM SOUTHERN SHORELINE OF LAKE ONTARIO AND
INLAND ACROSS THE NORTHERN GENESEE VALLEY AND TOWARDS THE WESTERN
FINGER LAKES REGION...AND BECOMING LESS LIKELY TOWARDS THE EASTERN
END OF LAKE ONTARIO.
NORTHWEST FLOW ACROSS LAKE ERIE WILL BE PERPENDICULAR...AND LOW
LEVEL LIFT AND CONVERGENCE IS NOT AS GREAT. SNOW OF LAKE ERIE WILL
BE FOCUSED UPON AREAS SOUTH OF BUFFALO...ACROSS SKI COUNTRY AND THE
SOUTHERN TIER.
TOWARDS SATURDAY NIGHT AN ARCTIC FRONT WILL BE DROPPING SOUTHWARD
ACROSS OUR REGION FROM SOUTHERN CANADA. BY 12Z SUNDAY EXPECT THIS
FRONT TO BE PUSHING TOWARDS THE SOUTHERN SHORELINE OF LAKE ONTARIO.
BEHIND THIS FRONT SFC TEMPERATURES WILL DROP INTO THE SINGLE DIGITS
AND LOWER...AND WITH WINDS LIKELY IN THE 5 TO 10 KNOTS RANGE WIND
CHILLS WILL FALL TO -20F OR LOWER SUNDAY MORNING ACROSS PORTIONS OF
THE NORTH COUNTRY. WILL MENTION THESE WIND CHILL TEMPERATURES IN THE
HWO...WITH FURTHER SHIFTS MONITORING FOR ANY WIND CHILL ADVISORIES.
AS THIS ARCTIC FRONT DROPS SOUTHWARD EXPECT THE BAND OF LAKE EFFECT
SNOW OFF LAKE ONTARIO TO BECOME ENHANCED. INCREASING WIND SPEEDS AND
COLD TEMPERATURES WILL CREATE BLUSTERY AND BLOWING SNOW CONDITIONS
EARLY SUNDAY MORNING...AND AS THE FRONT DROPS SOUTHWARD EXPECT THIS
BOUNDARY TO TAKE THE LAKE EFFECT SNOWBAND AND PUSH IT SOUTHWARD WELL
INLAND ACROSS SOUTH OF LAKE ONTARIO. THIS MAY CREATE A SEVERAL HOUR
PERIOD OF REDUCED VISIBILITIES WITHIN THE BLOWING AND FALLING SNOW.
LAKE EFFECT SNOW/SNOW ALONG THE ARCTIC FRONT WILL CONTINUE THROUGH
THE DAY SUNDAY WITH THE FOCUS ALONG THE ARCTIC FRONT. WIND SHEER MAY
DISRUPT THE BANDS THROUGH THE DAY SUNDAY TO HOLD SIGNIFICANT
ACCUMULATIONS FROM OCCURRING AT ANY GIVEN LOCATION. WAA STARTS LATER
IN THE DAY SUNDAY...BUT WITH THE DEEP COLD AIRMASS TEMPERATURES
SUNDAY WILL REMAIN COLD ENOUGH TO SUPPORT LAKE EFFECT
ACTIVITY...WHILE AFTERNOON HIGHS REMAIN BELOW NORMAL.
HIGH PRESSURE FOLLOWING THE ARCTIC FRONT WILL BUILD ACROSS THE NORTH
COUNTRY SUNDAY AND WILL JUST HAVE CHC POPS EARLY SUNDAY ACROSS THE
NORTH COUNTRY...WHILE SOUTHWARD WILL HAVE LIKELY TO CATEGORICAL
POPS.
LAKE EFFECT SNOW WILL DIMINISH SUNDAY NIGHT AND AS THE WINDS
BACK...LIFT NORTHWARD TOWARDS THE EASTERN LAKE ONTARIO REGION
MONDAY. AS THE UPPER LEVEL RIDGE BUILDS ACROSS THE REGION MONDAY
EXPECT SKIES TO CLEAR...WITH TEMPERATURES RISING BACK TO THE
FREEZING MARK...AND NEAR NORMAL.
CLOUDS WILL INCREASE THROUGH THE NIGHT MONDAY NIGHT AS THE NEXT
SYSTEM FROM THE WEST NEARS THE REGION WITH LIGHT SNOW RETURNING LATE
TO WNY.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
SEVERAL UPPER LEVEL SHORT WAVES THROUGH A SPLIT FLOW THIS TIME
PERIOD WILL CREATE AN ACTIVE TIME PERIOD FOR THE LONG RANGE...THOUGH
EACH SINGLE SYSTEM AT PRESENT MOMENT DOES NOT APPEAR SIGNIFICANT.
WITH A RETURN TO A MORE ZONAL FLOW THIS PERIOD TEMPERATURES WILL
AVERAGE AROUND NORMAL...WITH ANY GREAT DEPARTURES FROM NORMAL COMING
ON ANY PHASING OF THE NORTHERN AND SOUTHERN SHORTWAVES...THEREBY
AMPLIFYING THE FLOW SOME.
TUESDAY THE GFS/ECMWF/GGEM BRING A WEAK SHORT WAVE EJECTING FROM THE
SOUTHWEST ACROSS THE EASTERN GREAT LAKES. TEMPERATURES ALOFT ON BOTH
THE GFS/ECMWF RANGE FROM -6 TO -8C AND WITH THE 06Z GEFS MEMBERS
SUPPORTING ALL SNOW WILL KEEP THE P-TYPE AS SNOW FOR VALENTINES DAY.
FOR NOW WILL LEAVE AS HIGH CHANCE POPS...AS QPF IS ON THE LIGHT SIDE
AND THE SHORT WAVE IS EXPECTED TO FLATTEN OUT AS IT NEARS THE NORTH
EAST. TEMPERATURES TUESDAY UNDER A CLOUDY SKY WILL NOT STRAY MUCH
FROM NORMAL.
WILL HAVE SNOW TAPERING OFF TUESDAY NIGHT WITH THE FLATTENING
SHORTWAVE PASSING BY.
TIMING AND STRENGTH OF THE NEXT SHORT WAVE...THIS TIME IN THE
NORTHERN BRANCH OF THE JET STREAM REMAINS UNCERTAIN. BOTH THE 12Z
GFS AND 12Z ECMWF HAVE BOTH BEEN HINTING AT A SHORT WAVE
CROSSING...THOUGH TIMING AND STRENGTH HAVE BEEN FLUCTUATING. WILL
CONTINUE WITH LOW CHC POPS FOR WEDNESDAY.
BOTH THE GFS AND ECMWF HAVE A SFC HIGH PRESSURE ACROSS THE REGION
WEDNESDAY NIGHT AND INTO THURSDAY MORNING AND THIS FEATURE WILL
ALLOW FOR DIMINISHING POP CHCS THOUGH WITH LOW LEVEL MOISTURE
REMAINING...AND POSSIBLY TRAPPED BELOW AN INVERSION WILL MAINTAIN
MOSTLY CLOUDY SKY CONDITIONS.
BOTH THE OPERATIONAL RUNS OF THE GFS AND ECMWF BRING ANOTHER
SHORTWAVE ACROSS THE EASTERN GREAT LAKES LATER THURSDAY AND
INTO FRIDAY ALONG WITH AN INCREASE IN MOISTURE. WILL BRING CHC POPS
BACK TO THE REGION LATE THURSDAY TO THE SOUTHERN TIER...AND THROUGH
THE NIGHT THURSDAY AND INTO FRIDAY.
PRECIPITATION TYPE WEDNESDAY THROUGH FRIDAY IS CHALLENGING AS 850S
RISE TO NEAR -4C ON THE GFS WEDNESDAY...THOUGH THE ECMWF MAINTAINS A
DEEPER COOL POOL OVER THE EASTERN GREAT LAKES. WILL HAVE BOTH RAIN
AND SNOW MENTIONED IN THE GRIDS FOR WEDNESDAY...
A MILDER RETURN FLOW BEHIND THE DEPARTING SFC HIGH THURSDAY AND
FRIDAY WILL ALSO ALLOW FOR PRECIPITATION TO COME AS A MIX OF RAIN AND
SNOW FOR LATER THURSDAY AND FRIDAY ACROSS THE REGION.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
00Z RADAR TRENDS AROUND THE REGION SHOW SNOW SHOWERS OVER WESTERN
AND CENTRAL LAKE ONTARIO CLOSER TO THE FRONTAL BOUNDARY...BUT
REMAINING OVER THE WATERS AND SHOULD NOT AFFECT ANY TAF SITE
DIRECTLY. WILL EXPECT GENERALLY LIGHT SNOW ACROSS THE REGION WITH
MVFR TO UPPER RANGE IFR CONDITIONS...THE IFR MOSTLY DUE TO
RESTRICTED VSBY.
CONDITIONS WILL LOWER SIGNIFICANTLY AT MOST SITES SATURDAY
MORNING...AS A FRONTAL BOUNDARY DROPS ACROSS THE REGION. THIS
FRONTAL PASSAGE WILL KEY A MORE INTENSE PERIOD OF SNOW...WITH IFR
OR LOWER CONDITIONS LIKELY TOWARD DAYBREAK SATURDAY INTO SATURDAY
MORNING.
AN IMPROVEMENT TO VFR CONDITIONS AFTER 21Z ON SATURDAY AS A DRIER
AIRMASS ARRIVES BEHIND THE PASSING COLD FRONT...BUT NOT TO LAST LONG
AS LAKE EFFECT SNOW ON COLD NORTHERLY WINDS BRINGS IFR CONDITIONS
BACK DURING SATURDAY NIGHT.
OUTLOOK...
SATURDAY NIGHT AND SUNDAY...PERIODS OF IFR OR LOWER IN LAKE EFFECT SNOW
SHOWERS.
MONDAY...MAINLY VFR.
TUESDAY AND WEDNESDAY...VFR/MVFR IN CHC OF SNOW.
&&
.MARINE...
WINDS HAVE LARGELY DIMINISHED ACROSS THE WATERS...WITH THE EXCEPTION
OF LAKE ERIE WHERE A SW FLOW SUPPORTS SMALL CRAFT HEADLINES INTO
THIS EVENING. AFTER THIS...THE KEY WILL BE A STRONG COLD
FRONT...WHICH WILL BRING A DECENT NORTHERLY FLOW IN ITS WAKE. FOR
NOW...WILL ISSUE THE SMALL CRAFT ADVISORY FOR THE SOUTH SHORES OF
LAKE ONTARIO. THIS WILL LIKELY HAVE TO BE EXTENDED TO LAKE
ERIE...BUT WILL LET FUTURE SHIFTS DO THIS AS HEADLINES ARE ALREADY
IN PLACE FOR ONGOING CONDITIONS.
WINDS SHOULD DIMINISH SATURDAY NIGHT...BUT ANOTHER FRONTAL BOUNDARY
WILL CAUSE WINDS TO INCREASE AGAIN ON SUNDAY AND SUNDAY NIGHT.
EXPECT SOLID SMALL CRAFT WINDS...WITH THE POSSIBILITY OF GALES
DURING THIS PERIOD. HIGH PRESSURE WILL BUILD TOWARD THE WATERS EARLY
NEXT WEEK.
ONE CONCERN IS THE POTENTIAL FOR FREEZING SPRAY ON SATURDAY NIGHT
INTO SUNDAY...AS TEMPERATURES DROP AND WINDS INCREASE.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...WINTER WEATHER ADVISORY FROM 4 AM TO 5 PM EST SATURDAY FOR
NYZ019-020.
MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EST THIS EVENING FOR LEZ040-
041.
SMALL CRAFT ADVISORY FROM 4 AM SATURDAY TO 5 AM EST
SUNDAY FOR LOZ042>044.
&&
$$
SYNOPSIS...APFFEL
NEAR TERM...APFFEL
SHORT TERM...THOMAS
LONG TERM...THOMAS
AVIATION...WCH
MARINE...APFFEL/RSH
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
621 AM EST THU FEB 9 2012
.SYNOPSIS...
BROAD HIGH PRESSURE WILL BUILD INTO EASTERN NC THROUGH TONIGHT. A
MODIFIED ARCTIC COLD FRONT WILL MOVE THROUGH ON SATURDAY WITH A
STRONG PUSH OF MUCH COLDER AIR BEHIND IT. ARCTIC HIGH PRESSURE OVER
THE NORTHERN PLAINS SATURDAY WILL MOVE SOUTHEAST...BECOMING CENTERED
OVER THE AREA ON MONDAY. THE HIGH WILL SHIFT OFFSHORE MONDAY NIGHT
AS ANOTHER DISTURBANCE MOVES IN FOR TUESDAY OR WEDNESDAY.
&&
.NEAR TERM /TODAY/...
AS OF 315 AM THUR...THE FA IS SANDWICHED BETWEEN DEPARTING LOW
PRESSURE TO THE NORTHEAST AND APPROACHING SFC HIGH PRES TO THE WEST
EARLY THIS MORNING. MOST OF E NC IS EXPERIENCING CLEAR SKIES...
EXCEPT FOR SOME LINGERING STRATUS ACROSS THE NE PORTIONS/OBX...
WHERE WRAP AROUND MOISTURE IS LINGERING. TEMPS ARE CURRENTLY IN THE
LOWER TO MID 30S INLAND WITH 40S NEAR THE IMMEDIATE COAST. SFC HIGH
PRES WILL BUILD IN TODAY WITH LIGHT NORTHERLY WINDS UNDER MOSTLY
SUNNY SKIES. UPR FLOW WILL BECOME ZONAL WITH SUBTROPICAL JET FEEDING
SOME INCREASE IN HIGH LEVEL CIRRUS TOWARD THE END OF THE DAY. LOW
LEVEL THICKNESSES INDICATE MAX TEMPS STRUGGLING TO REACH THE 50
DEGREE MARK IN MOST AREAS...WITH MID 40S FOR THE OBX WHERE A STIFF
NORTH BREEZE WILL PERSIST.
&&
.SHORT TERM /TONIGHT/...
AS OF 315 AM THUR...X-SECTION ANALYSIS INDICATES FURTHER INCREASING
OF UPR LEVEL MOISTURE AS WEAK IMPULSE SLIDES THROUGH IN MEAN
WESTERLY FLOW ALOFT. THIS WILL HAVE IMPLICATIONS ON MIN TEMPS
OVERNIGHT. SFC HIGH WILL BE CENTERED OVERHEAD...THOUGH WITH THE
THICKER CLOUD CANOPY EXPECTED...IDEAL RADIATIONAL COOLING CONDITIONS
WILL NOT BE REALIZED...SO WENT A BIT HIGHER FOR MIN TEMPS...WITH
MOST AREAS REMAINING AROUND THE FREEZING MARK. SHOULD CIRRO STRATUS
DECK THIN OR MOVE OUT BEFORE 12Z...MIN TEMPS WOULD BE A BIT
COOLER...IN THE MID 20S...THAN CURRENTLY ADVERTISED.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
AS OF 345 AM THURSDAY...THE SURFACE HIGH MOVES OFF OF THE COAST
FRIDAY WITH RETURN SW FLOW HELPING TO BOOST HIGH TEMPERATURES TO
AROUND 60 DEGREES. CLOUDS WILL BE ON THE INCREASE AHEAD OF NEXT
SYSTEM LATE IN THE DAY WITH A SMALL RISK OF A STRAY SHOWER OR TWO
TOWARDS EVENING AS LOW LEVEL WARM ADVECTION COMMENCES. AMPLITUDE OF
DIGGING SHORTWAVE/LONG WAVE TROUGH FRIDAY NIGHT WILL HAVE ENOUGH
AMPLITUDE TO TAP THE ATLANTIC. WITH MORE MOISTURE TO WORK WITH
AND GOOD LIFT ASSOCIATED WITH A STRONG SHORTWAVE...EXPECT MORE
WIDESPREAD COVERAGE OF PRECIPITATION. WILL INCREASE POPS TO 50%.
MET/MAV MOS WERE ALL INDICATING LIKELY POPS DURING THIS TIME AND
IF THIS TREND CONTINUES POPS WILL BE RAISED ON SUBSEQUENT UPDATES.
THE DEEPENING LONG WAVE TROUGH OVER THE EASTERN US WILL FACILITATE
CYCLOGENESIS OVER OR JUST OFFSHORE OF EASTERN NC FRIDAY NIGHT WITH
THE STRENGTHENING LOW MOVING JUST OFF THE EASTERN SEABOARD ON
SATURDAY. CONSENSUS OF THE GUIDANCE IS FOR MOST OF THE SIGNIFICANT
PRECIPITATION TO BE OVER BY 12Z SATURDAY BUT WILL HOLD ONTO SLIGHT
CHANCE POPS ALL DAY AS BASE OF UPPER TROUGH MOVES THROUGH THE
REGION. THE DEEPENING LOW WILL PRODUCE STRONG NW WINDS ACROSS THE
AREA. THESE NW WINDS WILL CAUSE MUCH COLDER AIR TO SWEEP INTO
EASTERN NC.
ANOTHER SHORTWAVE WILL ROTATE AROUND THE BASE OF THE UPPER TROUGH
SATURDAY EVENING. MOISTURE WILL BE VERY LIMITED WITH THIS SYSTEM
AND WHAT MOISTURE THERE IS WILL PASS TO OUR NORTH. WILL STILL HANG
ONTO A SLIGHT CHANCE FOR EVENING SNOW SHOWERS DUE TO THE STRENGTH
OF THE UPPER SYSTEM BUT NOT EXPECTING ANY SIGNIFICANT ACCUMULATIONS
IF THE SNOW SHOWERS DEVELOP.
AN ARCTIC AIR INTRUSION WILL BE MAIN FOCUS FOR LATE SATURDAY NIGHT
THROUGH THE MONDAY PERIOD AS STRONG HIGH PRESSURE BUILDS OVER THE
AREA WITH BELOW NORMAL TEMPERATURES EXPECTED. THE COLD AIR WILL
PEAK OVER THE AREA SUNDAY WHEN HIGHS WILL STRUGGLE TO REACH THE
LOWER 40S. RETURN FLOW FROM HIGH PRESSURE MOVING OFFSHORE ALONG WITH
WAA AND SHORT WAVES ALOFT WILL SUPPORT SLIGHT CHANCE POPS FOR
TUESDAY THROUGH WEDNESDAY...ALONG WITH MODERATING TEMPS. THERE
STILL WERE SIGNIFICANT DIFFERENCES IN THE MODELS FOR THE FORECAST
FROM TUESDAY AND BEYOND.
THE LONG RANGE FORECAST INDICES WERE SENDING MIXED SIGNALS FOR MID
FEBRUARY. THE PNA IS FORECAST TO REMAIN STRONGLY POSITIVE THROUGH
MID FEBRUARY WHICH USUALLY MEANS COLDER TEMPERATURES FOR THE
EASTERN US. HOWEVER...THE NAO AND AO HAVE BEEN POSITIVE FOR MUCH
OF THIS WINTER AND THIS HAS BEEN THE REASON FOR OUR MILD WINTER
THUS FAR. THE CPC ENSEMBLE FORECAST FOR BOTH THESE INDEXES THROUGH
FEBRUARY REMAIN POSITIVE ALTHOUGH THE GFS WAS INDICATING A PERIOD
OF NEGATIVE AO. THE LATEST CPC FORECAST HAS SIDED WITH THE ENSEMBLES
AND IS CALLING FOR A CONTINUATION OF THE MILD TEMPERATURES WITH
BETTER CHANCES FOR MUCH NEEDED RAINFALL DURING THE NEXT 7-14 DAYS.
&&
.AVIATION /11Z THURSDAY THROUGH MONDAY/...
SHORT TERM /THROUGH TONIGHT/...
AS OF 630 AM THUR...SHALLOW INVERSION WILL BREAK SHORTLY AFTER
SUNRISE THIS MORNING...AND ANY LIGHT FOG WILL BURN OFF THEN. LIGHT
NORTHERLY FLOW EXPECTED DURING THE DAY UNDER MOSTLY SUNNY SKIES.
WINDS DECOUPLE WITH SFC HIGH LOCATED OVERHEAD TONIGHT. SCT/BKN
CIRRUS EXPECTED TO OVER SPREAD THE AREA TONIGHT...SO FOG/BR
POTENTIAL IS QUESTIONBLE AT BEST FOR TONIGHT.
LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 345 AM THURSDAY...VFR CONDITIONS ARE EXPECTED FOR THE
MAJORITY OF THE LONG TERM FORECAST PERIOD. LOCAL BRIEF MVFR
CONDITIONS ARE POSSIBLE WITH LIGHT SHOWER ACTIVITY LATE FRIDAY.
MORE SUBSTANTIAL RAINFALL COULD OCCUR FRIDAY NIGHT INTO SATURDAY
MORNING WITH A BETTER CHANCE FOR SUB VFR CONDITIONS. GUSTY NW TO
N WINDS WILL ACCOMPANY AN ARCTIC AIR INTRUSION LATE SATURDAY INTO
SUNDAY.
&&
.MARINE...
SHORT TERM /TODAY AND TONIGHT/...
AS OF 630 AM THUR...EXTENDED SCA SEVERAL MORE HOURS...UNTIL 10
AM...AS GRADIENT IS SLOW TO RELAX DUE TO CONTINUING DEEPENING OF
THE DEPARTING LOW PRES TO THE NORTHEAST. RUC HAS CONTINUED TO
PERFORM WELL IN REGARDING 3 HOURLY PRES RISES AND WINDS FOR THE
COASTAL WATERS...AND HAS THEM DIMINISHING AFTER MID MORNING THIS
MORNING. BUOY 10NE OF DUCK HAS BEEN OBSERVING 6 FOOT SEAS OVER THE
LAST SEVERAL HOURS AND WILL CONTINUE TO DO SO THROUGH MID
MORNING... BEFORE SUBSIDING AFTER THAT.
PREVIOUS DISCUSSION...AS OF 315 AM THUR...GRADIENT WILL SLOWLY
SUBSIDE TODAY AS DEEP LOW PRESSURE PULLS AWAY TO THE CANADIAN
MARITIMES AND SFC HIGH PRES APPROACHES. 20-25 KT WINDS EARLY THIS
MORNING WILL SUBSIDE TO 15 TO 20 KT FOR THE OUTER WATERS...AND
DIMINISH FURTHER TO 10 TO 15 KT THIS AFTERNOON. THE HIGH WILL
BUILD IN OVER THE WATERS THIS EVENING...WITH WINDS GENERALLY 5 KT
AND BACKING WESTERLY LATE. SEAS WILL FOLLOW SUIT AND SUBSIDE
THROUGH THE PERIOD...BECOMING 1 TO 3 FEET LATE TONIGHT.
LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 345 AM THURSDAY...LIGHT WINDS AND 2-3 FT SEAS ARE FORECAST
FOR FRIDAY AS HIGH PRESSURE SLOWLY MOVES EAST OF THE WATERS. SW
WINDS WILL INCREASE TO 15 TO 20 KT AND SEAS TO 4 TO 5 FT FRIDAY
NIGHT AND SATURDAY AHEAD OF A DEVELOPING AREA OF LOW PRESSURE
VICINITY OF THE NC COAST. DETERIORATING CONDITIONS EXPECTED LATE
SATURDAY INTO SUNDAY AS THE LOW MOVES NE OF THE WATERS AND STRONG
NW FLOW DEVELOPS OVER THE WATERS. STRONG SMALL CRAFT TO GALE FORCE
WINDS WILL BE POSSIBLE. WILL INCREASE WINDS TO 30 KT WITH THIS
ISSUANCE AND WILL HAVE TO MONITOR THREAT FOR GALES SATURDAY WITH
SMALL CRAFT CONDITIONS EXPECTED THROUGHOUT SUNDAY. SEAS WILL PEAK
AT 7-9 FT SATURDAY AND EARLY SUNDAY. WINDS ARE FORECAST TO DIMINISH
MONDAY WITH THE SURFACE HIGH CENTER BUILDING OVER THE WATERS.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 10 AM EST THIS MORNING FOR AMZ150-
152.
&&
$$
SYNOPSIS...TL
NEAR TERM...TL
SHORT TERM...TL
LONG TERM...JBM/JME
AVIATION...TL/JME
MARINE...TL/JME
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
1022 AM CST THU FEB 9 2012
.DISCUSSION...
MAIN CHALLENGE TODAY WILL BE THE PASSAGE OF THE COLD FRONT. WINDS
HAVE SWITCHED TO THE NORTH IN THE NORTHERN FA AS THE FRONT
APPEARS TO LIE ALONG A KROX-KGFK-CARRINGTON LINE. THIS FRONT WILL
DROP SOUTH THRU THE ENTIRE FA THRU THE DAY BRINGING GUSTY NORTH
WINDS IN ITS WAKE. TEMPS ARE ACTUALLY RUNNING FAIRLY MILD SO FAR
WITH TEMPS NEAR 20F IN THE NORTH WHERE THE WIND SWITCH HAS ALREADY
OCCURRED. SEEMS LIKE TEMPS ACTUALLY CLIMB AS THE WINDS GO TO THE
WEST SO MANY AREAS WILL BE MILD TODAY ESPECIALLY EARLY. KJMS AT
27F WITH WEST WINDS. THEREFORE NOTCHED TEMPS UP A LITTLE BIT TO
MATCH THE RUC WHICH SEEMS TO MATCH CURRENT CONDITIONS THE BEST.
LOOKS LIKE THE STRONGEST WINDS SHOULD BE BY EARLY TO MID AFTERNOON
THEN THEY WILL START DROPPING IN THE LATE AFTERNOON AND EARLY
EVENING.
&&
.AVIATION...
WINDS HAVE SWITCHED TO THE NORTH AT KDVL AND KGFK NOW AS THE COLD
FRONT HAS ARRIVED. KTVF SHOULD BE NEXT AND THEN KFAR/KBJI WILL
SWITCH IN A FEW HOURS. THERE ARE SOME LOWER CEILINGS COMING DOWN
WITH THE FRONT BUT THEY SHOULD NOT LAST FOR VERY LONG.
&&
.PREV DISCUSSION... /ISSUED 307 AM CST THU FEB 9 2012/
SHORT TERM...
WINDS TODAY AND TEMPERATURES THROUGHOUT THE PERIOD WILL BE THE
MAIN FORECAST CONCERNS FOR THE SHORT TERM.
WV LOOP AND UPPER AIR ANALYSIS SHOW A DECENT SHORTWAVE COMING DOWN
THE BACKSIDE OF THE POLAR VORTEX CENTERED OVER THE EAST SIDE OF
HUDSON BAY. HEIGHTS WILL FALL THROUGHOUT THE DAY TODAY AS THE
SHORTWAVE DIGS DOWN. THE COLD FRONT THAT THE SHORTWAVE WILL HELP
BRING DOWN IS CURRENTLY HALFWAY THROUGH MANITOBA AND SEEMS TO BE
ON TRACK FOR ENTERING OUR NORTHERN CWA LATE THIS MORNING AND
PUSHING THE REST OF THE WAY THROUGH OUR COUNTIES THIS AFTERNOON.
THINK THAT AT LEAST THE NORTHERN COUNTIES WILL SEE FALLING TEMPS
THIS AFTERNOON UNDER STRONG COLD AIR ADVECTION SO INCLUDED A NON-
DIURNAL TEMPERATURE CURVE. CANADIAN RADAR HAS A NARROW BAND OF
RETURNS...BUT NOTHING SEEMS TO BE REACHING THE GROUND AT THIS
POINT. WILL KEEP AN EYE ON IT IN CASE A FLURRY MENTION NEEDS TO BE
ADDED JUST BEFORE THE FORECAST GOES OUT.
WINDS BEHIND THE COLD FRONT WILL BECOME QUITE BREEZY. THERE WILL
BE SOME GOOD MIXING THIS AFTERNOON...BUT 925 AND 850MB WINDS ARE
ONLY AROUND 20 TO 30 KTS OR SO. COLD AIR ADVECTION IS
STRONG...BUT MODELS ARE ALL PRETTY CONSISTENT ON KEEPING THE
HIGHEST WIND SPEEDS TO OUR SOUTHWEST. THINK THAT WINDS WILL STAY
BELOW ADVISORY CRITERIA AT THIS POINT. WINDS WILL BEGIN TO FALL
OFF TONIGHT...BUT NOT A HUGE AMOUNT AND MAY STILL BE AROUND 10 KTS
BY DAYBREAK. WITH CLEARING SKIES AND THE COLD AIR
MASS AS WELL AS A BIT OF LINGERING SNOW COVER...TEMPERATURES WILL BE
WELL BELOW ZERO ACROSS THE NORTHERN 2/3RDS OF THE CWA. WIND CHILLS
ARE EXPECTED TO DROP BELOW -20...WITH SOME LOCATIONS IN THE NORTH
BELOW -30. WILL INCLUDE AN SPS AND MENTION IN THE HWO...BUT NO
HEADLINES AT THIS TIME.
THE COLD SFC HIGH WILL CONTINUE THROUGH THE DAY ON FRIDAY...AND
EVEN WITH SUNNY SKIES TEMPS WILL NOT WARM MUCH. KEPT HIGHS IN THE
SINGLE DIGITS. THE NORTH TO NORTHWESTERLY FLOW ALOFT WILL CONTINUE
THROUGH FRIDAY NIGHT AND SATURDAY...WITH THE SFC HIGH STILL
HANGING AROUND THE PLAINS. TEMPS WILL CONTINUE TO BE FAIRLY COOL
THROUGH SATURDAY. THE TROUGH MOVES OFF TO THE EAST SATURDAY NIGHT
AND SFC WINDS SHIFT TO THE WEST AND SOUTHWEST AS THE SFC HIGH
CENTER MOVES SOUTH. THINK THAT TEMPS SHOULD BEGIN TO MODERATE A
BIT BY SATURDAY NIGHT.
LONG TERM...SUNDAY THROUGH WEDNESDAY NIGHT
SUNDAY THROUGH MONDAY...A WEAK UPPER LOW WILL MOVE SLOWLY EASTWARD
FROM MT INTO THE EASTERN DAKOTAS. MOST PRECIPITATION WITH THIS WAVE
WILL BE ACROSS SOUTHERN MN INTO WESTERN WI...BUT WILL MAINTAIN
SLIGHT CHANCE POPS ACROSS THE FAR SOUTHEASTERN FORECAST AREA ON
MONDAY. THEREAFTER...FLOW ALOFT TURNS NORTHWESTERLY WITH A COUPLE OF
WEAK...ILL-TIMED SHORT-WAVES MOVING THROUGH THE REGION. AIR MASS IS
DRY AND WILL KEEP FORECAST PRECIPITATION-FREE. TEMPERATURES WILL
SLOWLY INCREASE EACH DAY INTO THE MIDDLE OF NEXT WEEK WITH HIGHS IN
THE 20S AND LOWS IN THE SINGLE DIGITS TO TEENS ABOVE ZERO.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
GODON
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
1241 PM EST THU FEB 9 2012
.SYNOPSIS...
HIGH PRESSURE TODAY. WEAK SYSTEM WITH RAIN OR SNOW FRIDAY. ARCTIC
COLD FRONT FRIDAY NIGHT FOR COLDER SNOW SHOWERS SATURDAY. COLD
SUNDAY. ANOTHER SYSTEM MONDAY NIGHT INTO TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
10 AM UPDATE...SATELLITE IMAGERY CONFIRMS 12Z MODEL DATA OF LOW
LEVEL MOISTURE/CLOUDS TRAPPED UNDER INVERSION...MAINLY SOUTH AND
WEST...WILL BE SLOW TO DISSIPATE THIS AFTERNOON. WILL UPDATE TO HOLD
CLOUDS LONGER INTO EARLY AFTERNOON AND LOWER HIGHS UNDER THE CLOUD
SHIELD A COUPLE OF DEGREES. NO PRECIP.
PREVIOUS DISCUSSION BELOW...
CONTENDING WITH LINGERING LOW STRATUS HERE ON THE GRAVEYARD
SHIFT. CLEARING HAS MADE IT JUST E OF OH RVR...WITH EXCEPTION OF
NE KY WHERE CLDS PERSIST. LLVL RH FIELDS OFF RUC SEEM TO HAVE A
GOOD HANDLE ON THINGS AND HAVE USED IT TO BASE SKY GRIDS THRU
EARLY MORNING. THIS ALLOWS DRY PUNCH TO PUSH CLEARING LINE FURTHER
E TO ABOUT I79 CORRIDOR BY 10Z. FROM THERE EXPECT CLDS OVER MTNS
TO DIS SPATE SHORTLY AFTER SUNRISE. THINK LOW CLDS WILL HANG TOUGH
ACROSS WESTERN LOWLANDS...NE KY...AND SW VA THRU LATE MORNING
BEFORE SCT OUT.
LEFT POPS UNCHANGED REST OF TONIGHT. ALSO LEFT THE PATCHY FRZDZ
ALONG WITH SHSN IN WX GRIDS ACROSS THE MTNS BEFORE ENDING BY 10Z.
SEEING KEKN REPORT UP FROM TIME TO TIME. HOWEVER...LOOKING AT
SOUNDINGS...SATURATION TO -10C SHOULD STILL SUPPORT ICE CRYSTALS.
TEMP WISE...SHOULD BE LOOKING AT SOMEWHAT OF A TEMP GRADIENT THIS
MORNING WITH SOME UPR TEENS SHOWING UP ACROSS SE OH WHERE A CLR
SKY WILL PREVAIL..WITH LOW TO MID 20S SHOWING UP CENTRAL/NORTHERN
LOWLANDS. ACROSS NE KY...SOUTHERN COAL FIELDS...SW VA WILL BE HARD
PRESSED TO FALL MUCH REMAINDER OF NIGHT GIVEN CLDS. CAA WILL ALLOW
NORTHERN MTNS TO DIP WELL INTO THE TEENS DESPITE LINGERING CLDS.
WEAK SFC HIGH CONTROLS WX FOR TDY WITH AREAS OF CIRRUS. MAY SEE
SOME LINGERING CU/STRATOCU CU ACROSS NE KY/WESTERN LOWLANDS FROM
RESIDUAL LLVL MOISTURE. TRIED TO GO A HAIR BLO GUIDANCE TDY FOR
HIGHS AND INCORPORATE LWR NUMBERS ACROSS AFOREMENTIONED AREAS THAT
HAVE TO CONTEND WITH SOME CLDS.
WEAK SFC HIGH SLIDES EAST OVERNIGHT AMID INCREASING SW FLOW ALOFT.
MID/HI CLDS INCREASE LATE FROM W AND S AHEAD OF NEXT SYS. TOOK A
BLEND OF GUIDANCE FOR LOWS TONIGHT WITH A NOD TOWARD MAV.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY NIGHT/...
FRIDAY FORECAST IS RATHER TRICKY. MODEL SOUNDINGS SHOW THAT ARRIVING
PRECIPITATION CAUSING THE COLUMN TO EVAPORATORY COOL INTO A SNOW
SOUNDING. CONCERNED HOWEVER ABOUT THE TIME OF DAY THAT SYSTEM IS
ARRIVING...DURING THE WARMEST PART OF THE DAY. ANY SUNSHINE FRIDAY
MORNING COULD HEAT THE BOUNDARY LAYER TOO MUCH. WILL GO WITH RAIN OR
SNOW FOR NOW.
ARCTIC COLD FRONT THEN ARRIVES FRIDAY NIGHT. SOME GOOD SNOW SHOWERS
CAN BE EXPECTED ALONG AND BEHIND THE ARCTIC FRONT...BUT TIMING IN
THE MODELS IS STILL A BIT UNCERTAIN. WILL INCREASE POPS.
&&
.LONG TERM /MONDAY THROUGH WEDNESDAY/...
SECONDARY OR REINFORCING COLD FRONT SWEEPS THROUGH NEW ENGLAND
SUNDAY BUT HAS LITTLE EFFECT ON CENTRAL APPALACHIANS AND MID OHIO
VALLEY. WITH THE COLD DAWN AND LIGHT WINDS...TRIED TO KEEP MAXIMUM
TEMPERATURES AT OR COLDER THAN 00Z MOS GUIDANCE AND HPC MEDIUM RANGE
GUIDANCE. CONSIDERING SATURDAY...COULD BE 2 STRAIGHT DAYS OF SUB
FREEZING TEMPERATURES. WE WERE EVEN A BIT SLOWER WARMING UP
MONDAY...BASED ON THE SLOWER 00Z ECMWF SOLUTION.
HIGH AND MID LEVEL MOISTURE INCREASES UP THE OHIO VALLEY MONDAY
NIGHT INTO TUESDAY...AS WE TRY TO SLOWLY MODIFY THE DRY ARCTIC AIR
NEAR THE SURFACE. WILL HAVE CHANCE POPS LATE MONDAY NIGHT INTO EARLY
TUESDAY MORNING...WITH SLIGHTLY HIGHER POPS OVER NORTHERN COUNTIES
AS WEAKENING 500 MB TROF LIFTS NORTHEAST INTO THE LOWER GREAT LAKES.
MAIN DILEMMA IS WHAT HAPPENS LATE TUESDAY INTO WEDNESDAY...BETWEEN
500 MB DISTURBANCE. THOUGHT POPS WOULD LOWER TUESDAY NIGHT...BEFORE
INCREASING WEDNESDAY INTO WEDNESDAY NIGHT. HAVE ALL RAIN FOR DAY 7
SYSTEM. 00Z MODEL SOLUTIONS HAD HIGHER 500 MB HEIGHTS HOLDING OVER
THE SOUTHEAST STATES...WITH THE WEDNESDAY SYSTEM. HOWEVER...NEW 12Z
GFS SEEMS TO BE RUSHING THE DAY 7 SYSTEM THROUGH FASTER...WITH LOWER
HEIGHTS OVER THE SOUTHEAST. WILL NOT JUMP ON THE FASTER 12Z GFS NOW.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
18Z THURSDAY THRU 18Z FRIDAY...
LOW LEVEL MOISTURE TRAPPED UNDER HIGH PRESSURE INVERSION. ANY
LINGERING MVFR CEILINGS WILL LIFT BY 00Z TO VFR...AND GENERALLY
DISSIPATE BY 04Z AS INVERSION WEAKENS AND SOME DRIER AIR MOVES IN.
SFC HIGH RETREATS TO E TONIGHT WITH SW FLOW ALOFT INCREASING AHEAD
OF NEXT WX SYS. MID/HI CLDS WILL BE ON THE INCREASE FROM S AND W BY
12Z FRI...BUT ANY MVFR CONDITIONS IN PRECIP WILL WAIT TIL AFTER 18Z.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z FRIDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: TIMING OF CLEARING EARLY TONIGHT COULD VARY A
FEW HRS.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 18 19 20 21 22 23 00 01 02 03 04 05
EST 1HRLY 13 14 15 16 17 18 19 20 21 22 23 00
CRW CONSISTENCY H H H H H H H H H H H H
HTS CONSISTENCY H H H H H H H H H H H H
BKW CONSISTENCY H M M M M M H H H H H H
EKN CONSISTENCY H H H H H H H H H H H H
PKB CONSISTENCY H H H H H H H H H H H H
CKB CONSISTENCY H H H H H H H H H H H H
AFTER 18Z FRIDAY...
IFR POSSIBLE IN SNOW SHOWERS FRIDAY NIGHT INTO SATURDAY NIGHT.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...RPY/30
NEAR TERM...JMV/30
SHORT TERM...RPY
LONG TERM...MZ/TAX
AVIATION...JMV
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
949 AM EST THU FEB 9 2012
.SYNOPSIS...
HIGH PRESSURE TODAY. WEAK SYSTEM WITH RAIN OR SNOW FRIDAY. ARCTIC
COLD FRONT FRIDAY NIGHT FOR COLDER SNOW SHOWERS SATURDAY. COLD
SUNDAY. ANOTHER SYSTEM MONDAY NIGHT INTO TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
10 AM UPDATE...SATELLITE IMAGERY CONFIRMS 12Z MODEL DATA OF LOW
LEVEL MOISTURE/CLOUDS TRAPPED UNDER INVERSION...MAINLY SOUTH AND
WEST...WILL BE SLOW TO DISSIPATE THIS AFTERNOON. WILL UPDATE TO HOLD
CLOUDS LONGER INTO EARLY AFTERNOON AND LOWER HIGHS UNDER THE CLOUD
SHIELD A COUPLE OF DEGREES. NO PRECIP.
PREVIOUS DISCUSSION BELOW...
CONTENDING WITH LINGERING LOW STRATUS HERE ON THE GRAVEYARD
SHIFT. CLEARING HAS MADE IT JUST E OF OH RVR...WITH EXCEPTION OF
NE KY WHERE CLDS PERSIST. LLVL RH FIELDS OFF RUC SEEM TO HAVE A
GOOD HANDLE ON THINGS AND HAVE USED IT TO BASE SKY GRIDS THRU
EARLY MORNING. THIS ALLOWS DRY PUNCH TO PUSH CLEARING LINE FURTHER
E TO ABOUT I79 CORRIDOR BY 10Z. FROM THERE EXPECT CLDS OVER MTNS
TO DIS SPATE SHORTLY AFTER SUNRISE. THINK LOW CLDS WILL HANG TOUGH
ACROSS WESTERN LOWLANDS...NE KY...AND SW VA THRU LATE MORNING
BEFORE SCT OUT.
LEFT POPS UNCHANGED REST OF TONIGHT. ALSO LEFT THE PATCHY FRZDZ
ALONG WITH SHSN IN WX GRIDS ACROSS THE MTNS BEFORE ENDING BY 10Z.
SEEING KEKN REPORT UP FROM TIME TO TIME. HOWEVER...LOOKING AT
SOUNDINGS...SATURATION TO -10C SHOULD STILL SUPPORT ICE CRYSTALS.
TEMP WISE...SHOULD BE LOOKING AT SOMEWHAT OF A TEMP GRADIENT THIS
MORNING WITH SOME UPR TEENS SHOWING UP ACROSS SE OH WHERE A CLR
SKY WILL PREVAIL..WITH LOW TO MID 20S SHOWING UP CENTRAL/NORTHERN
LOWLANDS. ACROSS NE KY...SOUTHERN COAL FIELDS...SW VA WILL BE HARD
PRESSED TO FALL MUCH REMAINDER OF NIGHT GIVEN CLDS. CAA WILL ALLOW
NORTHERN MTNS TO DIP WELL INTO THE TEENS DESPITE LINGERING CLDS.
WEAK SFC HIGH CONTROLS WX FOR TDY WITH AREAS OF CIRRUS. MAY SEE
SOME LINGERING CU/STRATOCU CU ACROSS NE KY/WESTERN LOWLANDS FROM
RESIDUAL LLVL MOISTURE. TRIED TO GO A HAIR BLO GUIDANCE TDY FOR
HIGHS AND INCORPORATE LWR NUMBERS ACROSS AFOREMENTIONED AREAS THAT
HAVE TO CONTEND WITH SOME CLDS.
WEAK SFC HIGH SLIDES EAST OVERNIGHT AMID INCREASING SW FLOW ALOFT.
MID/HI CLDS INCREASE LATE FROM W AND S AHEAD OF NEXT SYS. TOOK A
BLEND OF GUIDANCE FOR LOWS TONIGHT WITH A NOD TOWARD MAV.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY NIGHT/...
FRIDAY FORECAST IS RATHER TRICKY. MODEL SOUNDINGS SHOW THAT ARRIVING
PRECIPITATION CAUSING THE COLUMN TO EVAPORATORY COOL INTO A SNOW
SOUNDING. CONCERNED HOWEVER ABOUT THE TIME OF DAY THAT SYSTEM IS
ARRIVING...DURING THE WARMEST PART OF THE DAY. ANY SUNSHINE FRIDAY
MORNING COULD HEAT THE BOUNDARY LAYER TOO MUCH. WILL GO WITH RAIN OR
SNOW FOR NOW.
ARCTIC COLD FRONT THEN ARRIVES FRIDAY NIGHT. SOME GOOD SNOW SHOWERS
CAN BE EXPECTED ALONG AND BEHIND THE ARCTIC FRONT...BUT TIMING IN
THE MODELS IS STILL A BIT UNCERTAIN. WILL INCREASE POPS.
&&
.LONG TERM /MONDAY THROUGH WEDNESDAY/...
SECONDARY OR REINFORCING COLD FRONT SWEEPS THROUGH NEW ENGLAND
SUNDAY BUT HAS LITTLE EFFECT ON CENTRAL APPALACHIANS AND MID OHIO
VALLEY. WITH THE COLD DAWN AND LIGHT WINDS...TRIED TO KEEP MAXIMUM
TEMPERATURES AT OR COLDER THAN 00Z MOS GUIDANCE AND HPC MEDIUM RANGE
GUIDANCE. CONSIDERING SATURDAY...COULD BE 2 STRAIGHT DAYS OF SUB
FREEZING TEMPERATURES. WE WERE EVEN A BIT SLOWER WARMING UP
MONDAY...BASED ON THE SLOWER 00Z ECMWF SOLUTION.
HIGH AND MID LEVEL MOISTURE INCREASES UP THE OHIO VALLEY MONDAY
NIGHT INTO TUESDAY...AS WE TRY TO SLOWLY MODIFY THE DRY ARCTIC AIR
NEAR THE SURFACE. WILL HAVE CHANCE POPS LATE MONDAY NIGHT INTO EARLY
TUESDAY MORNING...WITH SLIGHTLY HIGHER POPS OVER NORTHERN COUNTIES
AS WEAKENING 500 MB TROF LIFTS NORTHEAST INTO THE LOWER GREAT LAKES.
MAIN DILEMMA IS WHAT HAPPENS LATE TUESDAY INTO WEDNESDAY...BETWEEN
500 MB DISTURBANCE. THOUGHT POPS WOULD LOWER TUESDAY NIGHT...BEFORE
INCREASING WEDNESDAY INTO WEDNESDAY NIGHT. HAVE ALL RAIN FOR DAY 7
SYSTEM. 00Z MODEL SOLUTIONS HAD HIGHER 500 MB HEIGHTS HOLDING OVER
THE SOUTHEAST STATES...WITH THE WEDNESDAY SYSTEM. HOWEVER...NEW 12Z
GFS SEEMS TO BE RUSHING THE DAY 7 SYSTEM THROUGH FASTER...WITH LOWER
HEIGHTS OVER THE SOUTHEAST. WILL NOT JUMP ON THE FASTER 12Z GFS NOW.
&&
.AVIATION /15Z THURSDAY THROUGH MONDAY/...
15Z THURSDAY THRU 12Z FRIDAY...
LOW LEVEL MOISTURE TRAPPED UNDER HIGH PRESSURE INVERSION. AREAS OF
MVFR CEILINGS SOUTH AND EAST OF A HTS-CRW-EKN LINE WILL LIFT BY 18Z
TO VFR AND GENERALLY DISSIPATE BY 22Z AS MIXING OCCURS.
SFC HIGH RETREATS TO E TONIGHT WITH SW FLOW ALOFT INCREASING AHEAD
OF NEXT WX SYS. MID/HI CLDS WILL BE ON THE INCREASE FROM S AND W BY
12Z FRI.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z FRIDAY...
FORECAST CONFIDENCE: HIGH.
ALTERNATE SCENARIOS: TIMING OF CLEARING COULD VARY A FEW HRS.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01
EST 1HRLY 09 10 11 12 13 14 15 16 17 18 19 20
CRW CONSISTENCY H H H H H H H H H H H H
HTS CONSISTENCY H H H H H H H H H H H H
BKW CONSISTENCY H H H H H H H H H H H H
EKN CONSISTENCY L H H H H H H H H H H H
PKB CONSISTENCY H H H H H H H H H H H H
CKB CONSISTENCY H H H H H H H H H H H H
AFTER 12Z FRIDAY...
IFR POSSIBLE IN SNOW SHOWERS FRIDAY NIGHT INTO SATURDAY NIGHT.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...RPY/30
NEAR TERM...JMV/30
SHORT TERM...RPY
LONG TERM...MZ/TAX
AVIATION...JMV
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
555 AM EST THU FEB 9 2012
.SYNOPSIS...
HIGH PRESSURE BUILDS IN TODAY. WEAK SYSTEM WITH RAIN OR SNOW FRIDAY.
ARCTIC COLD FRONT FRIDAY NIGHT FOR COLDER SNOW SHOWERS SATURDAY.
COLD SUNDAY. ANOTHER SYSTEM MONDAY NIGHT INTO TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
11Z UPDATE...
MAIN ISSUE TDY CONT TO BE TIMING OF EROSION OF STRATUS LYR. THUS
FAR...SATELLITE IMAGERY CONFIRMS FCST ON TRACK REGARDING SKY GRIDS
AND DEGREE OF CLRING. WILL CONT TO LEAN ON RUC RH FIELDS NEAR H85
FOR CLDS TDY. AS A RESULT...JUST SOME TWEAKING OF SKY GRIDS
NEEDED...BASICALLY TO KEEP MORE IN THE WAY OF CLD ACROSS NE KY AND
SW WV THRU MIDDAY. STILL...GIVEN HOW SHALLOW THIS MOISTURE DEPTH
IS...THINK WITH DAYTIME HEATING...MUCH OF THIS SHOULD MIX OUT OR
ATLEAST BEGIN TO BREAK UP. CONT TO KEEP THOSE AREAS A COUPLE
DEGREES COOLER.
PREVIOUS DISCUSSION BELOW...
CONTENDING WITH LINGERING LOW STRATUS HERE ON THE GRAVEYARD
SHIFT. CLEARING HAS MADE IT JUST E OF OH RVR...WITH EXCEPTION OF
NE KY WHERE CLDS PERSIST. LLVL RH FIELDS OFF RUC SEEM TO HAVE A
GOOD HANDLE ON THINGS AND HAVE USED IT TO BASE SKY GRIDS THRU
EARLY MORNING. THIS ALLOWS DRY PUNCH TO PUSH CLEARING LINE FURTHER
E TO ABOUT I79 CORRIDOR BY 10Z. FROM THERE EXPECT CLDS OVER MTNS
TO DIS SPATE SHORTLY AFTER SUNRISE. THINK LOW CLDS WILL HANG TOUGH
ACROSS WESTERN LOWLANDS...NE KY...AND SW VA THRU LATE MORNING
BEFORE SCT OUT.
LEFT POPS UNCHANGED REST OF TONIGHT. ALSO LEFT THE PATCHY FRZDZ
ALONG WITH SHSN IN WX GRIDS ACROSS THE MTNS BEFORE ENDING BY 10Z.
SEEING KEKN REPORT UP FROM TIME TO TIME. HOWEVER...LOOKING AT
SOUNDINGS...SATURATION TO -10C SHOULD STILL SUPPORT ICE CRYSTALS.
TEMP WISE...SHOULD BE LOOKING AT SOMEWHAT OF A TEMP GRADIENT THIS
MORNING WITH SOME UPR TEENS SHOWING UP ACROSS SE OH WHERE A CLR
SKY WILL PREVAIL..WITH LOW TO MID 20S SHOWING UP CENTRAL/NORTHERN
LOWLANDS. ACROSS NE KY...SOUTHERN COAL FIELDS...SW VA WILL BE HARD
PRESSED TO FALL MUCH REMAINDER OF NIGHT GIVEN CLDS. CAA WILL ALLOW
NORTHERN MTNS TO DIP WELL INTO THE TEENS DESPITE LINGERING CLDS.
WEAK SFC HIGH CONTROLS WX FOR TDY WITH AREAS OF CIRRUS. MAY SEE
SOME LINGERING CU/STRATOCU CU ACROSS NE KY/WESTERN LOWLANDS FROM
RESIDUAL LLVL MOISTURE. TRIED TO GO A HAIR BLO GUIDANCE TDY FOR
HIGHS AND INCORPORATE LWR NUMBERS ACROSS AFOREMENTIONED AREAS THAT
HAVE TO CONTEND WITH SOME CLDS.
WEAK SFC HIGH SLIDES EAST OVERNIGHT AMID INCREASING SW FLOW ALOFT.
MID/HI CLDS INCREASE LATE FROM W AND S AHEAD OF NEXT SYS. TOOK A
BLEND OF GUIDANCE FOR LOWS TONIGHT WITH A NOD TOWARD MAV.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY NIGHT/...
FRIDAY FORECAST IS RATHER TRICKY. MODEL SOUNDINGS SHOW THAT ARRIVING
PRECIPITATION CAUSING THE COLUMN TO EVAPORATORY COOL INTO A SNOW
SOUNDING. CONCERNED HOWEVER ABOUT THE TIME OF DAY THAT SYSTEM IS
ARRIVING...DURING THE WARMEST PART OF THE DAY. ANY SUNSHINE FRIDAY
MORNING COULD HEAT THE BOUNDARY LAYER TOO MUCH. WILL GO WITH RAIN OR
SNOW FOR NOW.
ARCTIC COLD FRONT THEN ARRIVES FRIDAY NIGHT. SOME GOOD SNOW SHOWERS
CAN BE EXPECTED ALONG AND BEHIND THE ARCTIC FRONT...BUT TIMING IN
THE MODELS IS STILL A BIT UNCERTAIN. WILL INCREASE POPS.
&&
.LONG TERM /MONDAY THROUGH WEDNESDAY/...
SECONDARY OR REINFORCING COLD FRONT SWEEPS THROUGH NEW ENGLAND
SUNDAY BUT HAS LITTLE EFFECT ON CENTRAL APPALACHIANS AND MID OHIO
VALLEY. WITH THE COLD DAWN AND LIGHT WINDS...TRIED TO KEEP MAXIMUM
TEMPERATURES AT OR COLDER THAN 00Z MOS GUIDANCE AND HPC MEDIUM RANGE
GUIDANCE. CONSIDERING SATURDAY...COULD BE 2 STRAIGHT DAYS OF SUB
FREEZING TEMPERATURES. WE WERE EVEN A BIT SLOWER WARMING UP
MONDAY...BASED ON THE SLOWER 00Z ECMWF SOLUTION.
HIGH AND MID LEVEL MOISTURE INCREASES UP THE OHIO VALLEY MONDAY
NIGHT INTO TUESDAY...AS WE TRY TO SLOWLY MODIFY THE DRY ARCTIC AIR
NEAR THE SURFACE. WILL HAVE CHANCE POPS LATE MONDAY NIGHT INTO EARLY
TUESDAY MORNING...WITH SLIGHTLY HIGHER POPS OVER NORTHERN COUNTIES
AS WEAKENING 500 MB TROF LIFTS NORTHEAST INTO THE LOWER GREAT LAKES.
MAIN DILEMMA IS WHAT HAPPENS LATE TUESDAY INTO WEDNESDAY...BETWEEN
500 MB DISTURBANCE. THOUGHT POPS WOULD LOWER TUESDAY NIGHT...BEFORE
INCREASING WEDNESDAY INTO WEDNESDAY NIGHT. HAVE ALL RAIN FOR DAY 7
SYSTEM. 00Z MODEL SOLUTIONS HAD HIGHER 500 MB HEIGHTS HOLDING OVER
THE SOUTHEAST STATES...WITH THE WEDNESDAY SYSTEM. HOWEVER...NEW 12Z
GFS SEEMS TO BE RUSHING THE DAY 7 SYSTEM THROUGH FASTER...WITH LOWER
HEIGHTS OVER THE SOUTHEAST. WILL NOT JUMP ON THE FASTER 12Z GFS NOW.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
12Z THURSDAY THRU 12Z FRIDAY...
CLEARING WILL WORK THRU NORTHERN MTNS BY 13Z...WITH SE OH AND
NORTHERN LOWLANDS GENERALLY CLR. GENERALLY LOW END VFR CIGS
LINGERS THRU 15Z ACROSS NE KY...SOUTHERN COALFIELDS...SW VA. THIS
INCLUDES KHTS.
ANY REAMING STRATUS BECOMES MORE SCT-BKN MIDDY BEFORE
TRYING TO MIX OUT IN AFTN. ELSEWHERE GENERALLY LOOKING AT JUST
SOME AFTN CIRRUS OR SCT 4 TO 5KFT BASE CU.
SFC HIGH RETREATS TO E TONIGHT WITH SW FLOW ALOFT INCREASING AHEAD
OF NEXT WX SYS. MID/HI CLDS WILL BE ON THE INCREASE FROM S AND W
BY 12Z FRI.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z FRIDAY...
FORECAST CONFIDENCE: HIGH.
ALTERNATE SCENARIOS: TIMING OF CLEARING COULD VARY A FEW HRS.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 11 12 13 14 15 16 17 18 19 20 21 22
EST 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17
CRW CONSISTENCY M M H H H H H H H H H H
HTS CONSISTENCY M H H H H H H H H H H H
BKW CONSISTENCY M M M H M M M M M H H H
EKN CONSISTENCY M M M H H H H H H H H H
PKB CONSISTENCY H H H H H H H H H H H H
CKB CONSISTENCY H H H H H H H H H H H H
AFTER 12Z FRIDAY...
IFR POSSIBLE IN SNOW SHOWERS FRIDAY NIGHT INTO SATURDAY NIGHT.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...RPY/30
NEAR TERM...30
SHORT TERM...RPY
LONG TERM...MZ/TAX
AVIATION...30
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
410 AM EST THU FEB 9 2012
.SYNOPSIS...
HIGH PRESSURE BUILDS IN TODAY. WEAK SYSTEM WITH RAIN OR SNOW FRIDAY.
ARCTIC COLD FRONT FRIDAY NIGHT FOR COLDER SNOW SHOWERS SATURDAY.
COLD SUNDAY. ANOTHER SYSTEM MONDAY NIGHT INTO TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
CONTENDING WITH LINGERING LOW STRATUS HERE ON THE GRAVEYARD SHIFT.
CLEARING HAS MADE IT JUST E OF OH RVR...WITH EXCEPTION OF NE KY
WHERE CLDS PERSIST. LLVL RH FIELDS OFF RUC SEEM TO HAVE A GOOD
HANDLE ON THINGS AND HAVE USED IT TO BASE SKY GRIDS THRU EARLY
MORNING. THIS ALLOWS DRY PUNCH TO PUSH CLEARING LINE FURTHER E TO
ABOUT I79 CORRIDOR BY 10Z. FROM THERE EXPECT CLDS OVER MTNS TO
DIS SPATE SHORTLY AFTER SUNRISE. THINK LOW CLDS WILL HANG TOUGH
ACROSS WESTERN LOWLANDS...NE KY...AND SW VA THRU LATE MORNING
BEFORE SCT OUT.
LEFT POPS UNCHANGED REST OF TONIGHT. ALSO LEFT THE PATCHY FRZDZ
ALONG WITH SHSN IN WX GRIDS ACROSS THE MTNS BEFORE ENDING BY 10Z.
SEEING KEKN REPORT UP FROM TIME TO TIME. HOWEVER...LOOKING AT
SOUNDINGS...SATURATION TO -10C SHOULD STILL SUPPORT ICE CRYSTALS.
TEMP WISE...SHOULD BE LOOKING AT SOMEWHAT OF A TEMP GRADIENT THIS
MORNING WITH SOME UPR TEENS SHOWING UP ACROSS SE OH WHERE A CLR
SKY WILL PREVAIL..WITH LOW TO MID 20S SHOWING UP CENTRAL/NORTHERN
LOWLANDS. ACROSS NE KY...SOUTHERN COAL FIELDS...SW VA WILL BE HARD
PRESSED TO FALL MUCH REMAINDER OF NIGHT GIVEN CLDS. CAA WILL ALLOW
NORTHERN MTNS TO DIP WELL INTO THE TEENS DESPITE LINGERING CLDS.
WEAK SFC HIGH CONTROLS WX FOR TDY WITH AREAS OF CIRRUS. MAY SEE
SOME LINGERING CU/STRATOCU CU ACROSS NE KY/WESTERN LOWLANDS FROM
RESIDUAL LLVL MOISTURE. TRIED TO GO A HAIR BLO GUIDANCE TDY FOR
HIGHS AND INCORPORATE LWR NUMBERS ACROSS AFOREMENTIONED AREAS THAT
HAVE TO CONTEND WITH SOME CLDS.
WEAK SFC HIGH SLIDES EAST OVERNIGHT AMID INCREASING SW FLOW ALOFT.
MID/HI CLDS INCREASE LATE FROM W AND S AHEAD OF NEXT SYS. TOOK A
BLEND OF GUIDANCE FOR LOWS TONIGHT WITH A NOD TOWARD MAV.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY NIGHT/...
FRIDAY FORECAST IS RATHER TRICKY. MODEL SOUNDINGS SHOW THAT ARRIVING
PRECIPITATION CAUSING THE COLUMN TO EVAPORATORY COOL INTO A SNOW
SOUNDING. CONCERNED HOWEVER ABOUT THE TIME OF DAY THAT SYSTEM IS
ARRIVING...DURING THE WARMEST PART OF THE DAY. ANY SUNSHINE FRIDAY
MORNING COULD HEAT THE BOUNDARY LAYER TOO MUCH. WILL GO WITH RAIN OR
SNOW FOR NOW.
ARCTIC COLD FRONT THEN ARRIVES FRIDAY NIGHT. SOME GOOD SNOW SHOWERS
CAN BE EXPECTED ALONG AND BEHIND THE ARCTIC FRONT...BUT TIMING IN
THE MODELS IS STILL A BIT UNCERTAIN. WILL INCREASE POPS.
&&
.LONG TERM /MONDAY THROUGH WEDNESDAY/...
SECONDARY OR REINFORCING COLD FRONT SWEEPS THROUGH NEW ENGLAND
SUNDAY BUT HAS LITTLE EFFECT ON CENTRAL APPALACHIANS AND MID OHIO
VALLEY. WITH THE COLD DAWN AND LIGHT WINDS...TRIED TO KEEP MAXIMUM
TEMPERATURES AT OR COLDER THAN 00Z MOS GUIDANCE AND HPC MEDIUM RANGE
GUIDANCE. CONSIDERING SATURDAY...COULD BE 2 STRAIGHT DAYS OF SUB
FREEZING TEMPERATURES. WE WERE EVEN A BIT SLOWER WARMING UP
MONDAY...BASED ON THE SLOWER 00Z ECMWF SOLUTION.
HIGH AND MID LEVEL MOISTURE INCREASES UP THE OHIO VALLEY MONDAY
NIGHT INTO TUESDAY...AS WE TRY TO SLOWLY MODIFY THE DRY ARCTIC AIR
NEAR THE SURFACE. WILL HAVE CHANCE POPS LATE MONDAY NIGHT INTO EARLY
TUESDAY MORNING...WITH SLIGHTLY HIGHER POPS OVER NORTHERN COUNTIES
AS WEAKENING 500 MB TROF LIFTS NORTHEAST INTO THE LOWER GREAT LAKES.
MAIN DILEMMA IS WHAT HAPPENS LATE TUESDAY INTO WEDNESDAY...BETWEEN
500 MB DISTURBANCE. THOUGHT POPS WOULD LOWER TUESDAY NIGHT...BEFORE
INCREASING WEDNESDAY INTO WEDNESDAY NIGHT. HAVE ALL RAIN FOR DAY 7
SYSTEM. 00Z MODEL SOLUTIONS HAD HIGHER 500 MB HEIGHTS HOLDING OVER
THE SOUTHEAST STATES...WITH THE WEDNESDAY SYSTEM. HOWEVER...NEW 12Z
GFS SEEMS TO BE RUSHING THE DAY 7 SYSTEM THROUGH FASTER...WITH LOWER
HEIGHTS OVER THE SOUTHEAST. WILL NOT JUMP ON THE FASTER 12Z GFS NOW.
&&
.AVIATION /09Z THURSDAY THROUGH MONDAY/...
06Z THURSDAY THRU 06Z FRIDAY...
WIDESPREAD MVFR/LOCAL IFR CONDITIONS IN LIGHT SNOW SHOWERS WILL
CONTINUE THROUGH AT LEAST 09Z ACROSS THE MTNS. HAVE COVERED WITH
TEMPO GROUPS ACROSS KBKW TO HIT IFR CIGS FROM TIME TO TIME.
CLEARING MAKES IT TO NEAR I79 CORRIDOR BY 09Z WITH CENTRAL AND
NORTHERN MTNS TRYING TO SCT OUT BY 12Z. GENERALLY LOW END VFR
LINGERS THRU 15Z ACROSS NE KY...SOUTHERN COALFIELDS...SW VA. THIS
INCLUDES KHTS.
ANY REAMING STRATUS BECOMES MORE SCT-BKN LATE MORNING AND
LINGERING THRU MIDDAY ACROSS NE KY AND WESTERN LOWLANDS. ELSEWHERE
GENERALLY LOOKING AT JUST SOME AFTN CIRRUS.
SFC HIGH RETREATS TO E TONIGHT WITH SW FLOW ALOFT INCREASING AHEAD
OF NEXT WX SYS. MID/HI CLDS WILL BE ON THE INCREASE FROM S AND W
BY 12Z FRI.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z FRIDAY...
FORECAST CONFIDENCE: HIGH.
ALTERNATE SCENARIOS: TIMING OF CLEARING COULD VARY A FEW HRS.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE THU 02/09/12
UTC 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17
EST 1HRLY 01 02 03 04 05 06 07 08 09 10 11 12
CRW CONSISTENCY M M M M H H H H H H H H
HTS CONSISTENCY M M H H H H H H H H H H
BKW CONSISTENCY M L M M M M M L H H H H
EKN CONSISTENCY M M M M M L L M H H H H
PKB CONSISTENCY M M H H H H H H H H H H
CKB CONSISTENCY L M M H H H H H H H H H
AFTER 06Z FRIDAY...
IFR POSSIBLE IN SNOW SHOWERS FRIDAY NIGHT INTO SATURDAY NIGHT.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...RPY/30
NEAR TERM...30
SHORT TERM...RPY
LONG TERM...MZ/TAX
AVIATION...30
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
204 AM EST THU FEB 9 2012
.SYNOPSIS...
HIGH PRESSURE BUILDS IN TODAY. ARCTIC COLD FRONT BLOWS THROUGH
FRIDAY NIGHT FOR COLDER WIND BLOWN WEEKEND. DRY SUNDAY INTO
MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
CONTENDING WITH LINGERING LOW STRATUS HERE ON THE GRAVEYARD SHIFT.
CLEARING HAS MADE IT JUST E OF OH RVR...WITH EXCEPTION OF NE KY
WHERE CLDS PERSIST. LLVL RH FIELDS OFF RUC SEEM TO HAVE A GOOD
HANDLE ON THINGS AND HAVE USED IT TO BASE SKY GRIDS THRU EARLY
MORNING. THIS ALLOWS DRY PUNCH TO PUSH CLEARING LINE FURTHER E TO
ABOUT I79 CORRIDOR BY 10Z. FROM THERE EXPECT CLDS OVER MTNS TO
DIS SPATE SHORTLY AFTER SUNRISE. THINK LOW CLDS WILL HANG TOUGH
ACROSS WESTERN LOWLANDS...NE KY...AND SW VA THRU LATE MORNING
BEFORE SCT OUT.
LEFT POPS UNCHANGED REST OF TONIGHT. ALSO LEFT THE PATCHY FRZDZ
ALONG WITH SHSN IN WX GRIDS ACROSS THE MTNS BEFORE ENDING BY 10Z.
SEEING KEKN REPORT UP FROM TIME TO TIME. HOWEVER...LOOKING AT
SOUNDINGS...SATURATION TO -10C SHOULD STILL SUPPORT ICE CRYSTALS.
TEMP WISE...SHOULD BE LOOKING AT SOMEWHAT OF A TEMP GRADIENT THIS
MORNING WITH SOME UPR TEENS SHOWING UP ACROSS SE OH WHERE A CLR
SKY WILL PREVAIL..WITH LOW TO MID 20S SHOWING UP CENTRAL/NORTHERN
LOWLANDS. ACROSS NE KY...SOUTHERN COAL FIELDS...SW VA WILL BE HARD
PRESSED TO FALL MUCH REMAINDER OF NIGHT GIVEN CLDS. CAA WILL ALLOW
NORTHERN MTNS TO DIP WELL INTO THE TEENS DESPITE LINGERING CLDS.
WEAK SFC HIGH CONTROLS WX FOR TDY WITH AREAS OF CIRRUS. MAY SEE
SOME LINGERING CU/STRATOCU CU ACROSS NE KY/WESTERN LOWLANDS FROM
RESIDUAL LLVL MOISTURE. TRIED TO GO A HAIR BLO GUIDANCE TDY FOR
HIGHS AND INCORPORATE LWR NUMBERS ACROSS AFOREMENTIONED AREAS THAT
HAVE TO CONTEND WITH SOME CLDS.
WEAK SFC HIGH SLIDES EAST OVERNIGHT AMID INCREASING SW FLOW ALOFT.
MID/HI CLDS INCREASE LATE FROM W AND S AHEAD OF NEXT SYS. TOOK A
BLEND OF GUIDANCE FOR LOWS TONIGHT WITH A NOD TOWARD MAV.
&&
.SHORT TERM /FRIDAY/...
HIGH PRESSURE OVER THE AREA THU NT EXITS FRI...ALLOWING THE MAIN
EVENT THIS PERIOD...AN ARCTIC COLD FRONT...TO APPROACH FROM THE NW.
AN UPPER LEVEL WAVE IN THE SW FLOW AHEAD OF THE APPROACHING S/W TROF
BRINGS SOME PRECIPITATION AHEAD OF THE SURFACE FRONT LATE FRI INTO
FRI N. UPPER SUPPORT ACTUALLY WEAKENS SOMEWHAT AS THE FRONT ITSELF
CROSSES...LEAVING LOW LEVEL CONVERGENCE AS THE MAIN FORCING.
UPSLOPE FLOW ENSURES BEHIND THE FRONT VERY LATE FRI NT AND CONTINUES
INTO SAT EVENING.
LOWS THU NT WERE CLOSE TO THE WELL CONVERGED NUMBERS AND LOOKED
GOOD. MODELS HINT AT SOME WARM ADVECTION CLOUD AOA H85 AS A WEAK
UPPER LEVEL S/W TROF / COOL POOL MOVES AWAY TO THE NE. EDGED HIGHS
FRI DOWN TOWARD THE LATEST GUIDANCE THOUGH THE ATMOSPHERE SHOULD BE
WELL MIXED IN THE SW FLOW AHEAD OF THE APPROACHING FRONT.
WENT CLOSER TO HIGHER MAV ON LOWS SAT MORNING WHICH WILL BE A
SENSITIVE FUNCTION OF THE TIMING ON THE FRONTAL PASSAGE WHICH SHOULD
BE JUST BEFORE DAWN. BLENDED IN NAM12 TEMPERATURES FOR THE
OVERNIGHT PERIOD TO REFLECT TEMPERATURES HOLDING UP MUCH OF THE
NT...UNTIL THE FRONT PASSES. THIS THEN AFFECTS THE TIMING ON THE
CHANGEOVER TO SNOW AND SNOWFALL AMOUNTS.
HIGHS WERE CLOSE TO CONVERGED GUIDANCE SAT WITH ONLY A SMALL
RECOVERY. GIVEN MIXING...THERE PROBABLY BE A DIURNAL RECOVERY
FOLLOWED BY A QUICK FALL SAT EVENING. LOWS SAT NT ALSO APPEARED
CLOSE TO GUIDANCE AND REASONABLE WITH WIND CHILLS IN THE SINGLE
DIGITS BELOW ZERO OVER THE HIGHER TERRAIN.
HAVE 4 TO 8 INCHES OF FLUFFY SNOW OVER THE HIGHER TERRAIN...SO WILL
ADD ADVISORY TYPE MENTION TO THE HWO.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
SECONDARY OR REINFORCING COLD FRONT SWEEPS THROUGH NEW ENGLAND
SUNDAY BUT HAS LITTLE EFFECT ON CENTRAL APPALACHIANS AND MID OHIO
VALLEY. WITH THE COLD DAWN AND LIGHT WINDS...TRIED TO KEEP MAXIMUM
TEMPERATURES AT OR COLDER THAN 00Z MOS GUIDANCE AND HPC MEDIUM RANGE
GUIDANCE. CONSIDERING SATURDAY...COULD BE 2 STRAIGHT DAYS OF SUB
FREEZING TEMPERATURES. WE WERE EVEN A BIT SLOWER WARMING UP
MONDAY...BASED ON THE SLOWER 00Z ECMWF SOLUTION.
HIGH AND MID LEVEL MOISTURE INCREASES UP THE OHIO VALLEY MONDAY
NIGHT INTO TUESDAY...AS WE TRY TO SLOWLY MODIFY THE DRY ARCTIC AIR
NEAR THE SURFACE. WILL HAVE CHANCE POPS LATE MONDAY NIGHT INTO EARLY
TUESDAY MORNING...WITH SLIGHTLY HIGHER POPS OVER NORTHERN COUNTIES
AS WEAKENING 500 MB TROF LIFTS NORTHEAST INTO THE LOWER GREAT LAKES.
MAIN DILEMMA IS WHAT HAPPENS LATE TUESDAY INTO WEDNESDAY...BETWEEN
500 MB DISTURBANCE. THOUGHT POPS WOULD LOWER TUESDAY NIGHT...BEFORE
INCREASING WEDNESDAY INTO WEDNESDAY NIGHT. HAVE ALL RAIN FOR DAY 7
SYSTEM. 00Z MODEL SOLUTIONS HAD HIGHER 500 MB HEIGHTS HOLDING OVER
THE SOUTHEAST STATES...WITH THE WEDNESDAY SYSTEM. HOWEVER...NEW 12Z
GFS SEEMS TO BE RUSHING THE DAY 7 SYSTEM THROUGH FASTER...WITH LOWER
HEIGHTS OVER THE SOUTHEAST. WILL NOT JUMP ON THE FASTER 12Z GFS NOW.
&&
.AVIATION /07Z THURSDAY THROUGH MONDAY/...
06Z THURSDAY THRU 06Z FRIDAY...
WIDESPREAD MVFR/LOCAL IFR CONDITIONS IN LIGHT SNOW SHOWERS WILL
CONTINUE THROUGH AT LEAST 09Z ACROSS THE MTNS. HAVE COVERED WITH
TEMPO GROUPS ACROSS KBKW TO HIT IFR CIGS FROM TIME TO TIME.
CLEARING MAKES IT TO NEAR I79 CORRIDOR BY 09Z WITH CENTRAL AND
NORTHERN MTNS TRYING TO SCT OUT BY 12Z. GENERALLY LOW END VFR
LINGERS THRU 15Z ACROSS NE KY...SOUTHERN COALFIELDS...SW VA. THIS
INCLUDES KHTS.
ANY REAMING STRATUS BECOMES MORE SCT-BKN LATE MORNING AND
LINGERING THRU MIDDAY ACROSS NE KY AND WESTERN LOWLANDS. ELSEWHERE
GENERALLY LOOKING AT JUST SOME AFTN CIRRUS.
SFC HIGH RETREATS TO E TONIGHT WITH SW FLOW ALOFT INCREASING AHEAD
OF NEXT WX SYS. MID/HI CLDS WILL BE ON THE INCREASE FROM S AND W
BY 12Z FRI.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z FRIDAY...
FORECAST CONFIDENCE: HIGH.
ALTERNATE SCENARIOS: TIMING OF CLRING COULD VARY A FEW HRS.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE THU 02/09/12
UTC 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17
EST 1HRLY 01 02 03 04 05 06 07 08 09 10 11 12
CRW CONSISTENCY M M M M H H H H H H H H
HTS CONSISTENCY M M H H H H H H H H H H
BKW CONSISTENCY M L M M M M M L H H H H
EKN CONSISTENCY M M M M M L L M H H H H
PKB CONSISTENCY M M H H H H H H H H H H
CKB CONSISTENCY L M M H H H H H H H H H
AFTER 06Z FRIDAY...
IFR AGAIN POSSIBLE IN SNOW SHOWERS FRIDAY NIGHT INTO SATURDAY NIGHT.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...RPY/30
NEAR TERM...30
SHORT TERM...TRM
LONG TERM...MZ/TAX
AVIATION...30
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1242 PM EST THU FEB 9 2012
.SYNOPSIS...
HIGH PRESSURE WILL REMAIN IN COMMAND OVER THE REGION THROUGH FRIDAY.
A COLD FRONT WILL MOVE ACROSS THE REGION FRIDAY NIGHT THROUGH MID
DAY ON SATURDAY. THEN ANOTHER AREA OF HIGH PRESSURE WILL BUILD BACK
IN SATURDAY EVENING AND REMAIN INTO MONDAY. THE NEXT FRONT WILL
APPROACH THE AREA LATE ON TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1240 PM...STRATO-CU IS SLOWLY SPREADING ACROSS THE
UPSTATE...THOUGH IT/S TAKING LONGER THAN EXPECTED TO MOVE INTO THE
NC FOOTHILLS. THAT/S STILL EXPECTED TO HAPPEN AND INCREASING CLOUDS
HAVE BEEN RETAINED IN THE GRIDS. A BAND OF HIGH CLOUDS IS ALSO
ADDING TO THE OPAQUE SKY COVER OVER THE UPSTATE AND SRN NC PIEDMONT.
AS OF 945 AM...A NEW WRINKLE HAS BEEN ADDED TO THE FORECAST FOR TDA
AS CLOUDS HAVE STARTED TO DEVELOP EAST OF THE MTNS...FROM GREENVILLE
OVER TO GAFFNEY. THE LATEST RUC AND NAM RH FIELDS IMPLY THAT THESE
CLOUDS...UP AROUND 4KFT...WILL SPREAD SLOWLY TO THE NORTH THIS
MORNING AS WEAK LLVL WARM ADVECTION DEVELOPS OVER THE REGION. THE
CLOUDS MAY EVENTUALLY SPREAD ACROSS THE NC FOOTHILLS AND UP ALONG
THE E SLOPES OF THE BLUE RIDGE. AT LEAST THAT/S WHAT I/VE DONE IN
THE GRIDS. THE 12 UTC GSO SOUNDING SHOWED THE MOIST LAYER AND
STRONG SUBSIDENCE INVERSION THAT IS SERVING TO KEEP IT FROM MIXING
OUT. OTHERWISE...TWEAKED DEWPOINTS UP A LITTLE EARLY IN THE
DAY...THOUGH THEY SHOULD MIX OUT MORE IN THE AFTN. OF COURSE...IF
THE CLOUD COVER IS TOO WIDESPREAD...THEN TEMPS AND DEWPOINTS WILL
NEED TO BE ADJUSTED. THIS IS LIABLE TO MAKE CONDITIONS EVEN LESS
FAVORABLE FOR CONTROLLED BURNS OVER THE FOOTHILLS THIS AFTN.
AS OF 615 AM...CLOUDS REMAIN PARKED ALONG THE WESTERN MOUNTAINS IN
LINGERING...BUT DIMINISHING...NORTHWEST FLOW MOISTURE. STRATOCUMULUS
HAS ALSO MANAGED TO DEVELOP IN THE NRLY FLOW OVER THE NRN NC
FOOTHILLS AND PIEDMONT. SKY COVER HAS BEEN INCREASED ALONG AND NORTH
OF INTERSTATE 40...BUT THE CLOUDINESS SHOULD NOT MAKE MUCH OF A RUN
SOUTHWARD TOWARD CHARLOTTE THIS MORNING GIVEN THE LIGHT DOWNSLOPE
FLOW OFF THE MOUNTAINS AND THE DRYING PROFILES.
OTHERWISE...SFC HIGH PRES WILL BUILD IN FROM THE WEST TODAY UNDER
ZONAL FLOW ALOFT. LEE TROUGHING IS EXPECTED TO DEVELOP AT THE SFC
JUST E OF THE BLUE RIDGE TO GIVE WINDS A LIGHT SW FLOW BY THIS AFTN.
LITTLE MORE THAN SCATTERED CIRRUS IS EXPECTED ONCE THE NW FLOW
MOISTURE QUITS. MAX TEMPS WILL LIKELY BE A CATEGORY BELOW NORMAL
THIS AFTN DESPITE THE DECENT INSOLATION. MID AND HIGH CLOUDS MAY
THICKEN A LITTLE TONIGHT...BUT MINS SHOULD BE AT OR BELOW GUIDANCE
IN THIS COOL AND DRY AIRMASS.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AT 3 AM EST THURSDAY...AN MEAN UPPER TROUGH WILL PERSIST OVER THE
EAST FROM FRIDAY THROUGH SATURDAY NIGHT. ON FRIDAY A SHORTWAVE
ROUNDING THIS TROUGH WILL MOVE FROM THE SOUTHERN PLAINS TO THE GULF
STATES. MEANWHILE...A COLD FRONT WILL FORM IN THE LEE OF THE
APPALACHIANS. MOISTURE ALONG THIS FRONT WILL SUPPORT THE DEVELOPMENT
OF PRECIPITATION...ESPECIALLY OVER THE MOUNTAINS WHERE A COLD NW
UPSLOPE FLOW WILL SET UP LATE IN THE DAY. THE NEW FRONT MOVES
RAPIDLY EAST FRIDAY NIGHT...DRYING THE LEE OF THE MOUNTAINS...BUT
MOISTURE REMAINS OVER THE NC MOUNTAINS. ANOTHER COLD FRONT ARRIVES
ON SATURDAY MORNING...ACCOMPANIED BY MUCH LESS MOISTURE THAN ITS
PREDECESSOR.
MODEL TIME HEIGHTS SUGGEST PRECIPITATION WILL BEGIN FRIDAY
EVENING...PERHAPS EXTENDING EAST OF THE BLUE RIDGE BRIEFLY. AS THE
FRONT MOVES EAST...PRECIPITATION WILL BE LEFT ALONG THE TN BORDER
INTO SATURDAY NIGHT. MODEL SOUNDINGS SUPPORT A RAIN OR SNOW
SCENARIO...WITH PLENTY OF MOISTURE PRESENT AT ICE NUCLEATION
TEMPERATURES AND NO WARM NOSE BENEATH. ONLY THE VALLEY FLOORS AND
THE FOOTHILLS CAN EXPECT RAIN EARLY FRIDAY EVENING...WITH SNOW
LEVELS RAPIDLY DROPPING TO VALLEY FLOORS LATE IN THE EVENING WHILE
PRECIPITATION ENDS IN THE FOOTHILLS. SNOW CONTINUES DOWN TO THE
VALLEY FLOORS ON SATURDAY...BUT WITH TIME THE EVENT WILL BECOME MORE
CONFINED TO THE TN BORDER REGION. AT THIS POINT IT APPEARS THAT
ACCUMULATIONS OF 1 TO 2 INCHES MAY BE POSSIBLE ALONG THE TN
BORDER...WITH HALF INCH AMOUNTS AT HIGHER ELEVATIONS ALONG THE BLUE
RIDGE.
TEMPERATURES WILL BE A FEW DEGREES ABOVE NORMAL ON FRIDAY AND FRIDAY
NIGHT...FALLING TO A FEW DEGREES BELOW NORMAL ON SATURDAY...AND
ALMOST 10 DEGREES BELOW NORMAL ON SATURDAY NIGHT.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 200 AM THURSDAY...THE MEDIUM RANGE FORECAST PICKS UP AT 12Z
ON SUNDAY WITH A DEEP UPPER TROUGH AXIS MOVING OFF THE ATLANTIC AND
A BROAD UPPER RIDGING PRESENT OVER THE CENTRAL CONUS. THE LATEST
MODELS ARE IN GOOD AGREEMENT WITH AN UPPER LVL RIDGE OF HIGH
PRESSURE BUILDING OVER THE EASTERN CONUS THROUGH MONDAY BEFORE A
SHORTWAVE SWINGS ACROSS THE CAROLINAS MONDAY NIGHT INTO TUESDAY
MORNING. ANOTHER UPPER LEVEL RIDGE OF HIGH PRESSURE IS FORECAST TO
BUILD ACROSS THE EASTERN STATES THROUGH LATE WEDNESDAY AND A MOIST
SOUTHWESTERLY FLOW WILL DEVELOP AHEAD OF A LOW PRESSURE SYSTEM
APPROACHING FROM THE WEST THURSDAY.
AT THE SFC...DRY WEATHER WITH COOLER TEMPERATURES ARE EXPECTED OVER
THE REGION AS A BROAD SURFACE HIGH BUILDS ACROSS THE EASTERN STATES
SUNDAY INTO MONDAY. THE LATEST 00Z GFS AND THE ECMWF SHOW BETTER
CONSISTENCY WITH THE TIMING OF A WEAK UPPER LEVEL SHORTWAVE SWINGING
ACROSS OUR CWFA BETWEEN 12Z AND 18Z TUESDAY. AS THICKNESS VALUES
DECREASE QUIT A BIT IN RESPONSE TO THE SHORTWAVE PASSAGE...OVERNIGHT
TEMPERATURES WILL BE COLD ENOUGH FOR WINTRY TYPE PCPN ACROSS MUCH OF
THE REGION. THEREFORE...I KEPT AT LEAST SLIGHT CHANCE POPS IN FOR
SNOW OVER THE MOUNTAINS/FOOTHILLS WITH RAIN SNOW MIX OVER THE LOWER
PIEDMONT AREA THROUGH TUESDAY MORNING. ANY WINTRY PCPN WILL SWITCH
TO RAIN SHOWERS AFTER SUNRISE AS TEMPERATURES RISE ABOVE FREEZING
LVL. ANOTHER SURFACE HIGH WILL BUILD INTO THE REGION FOR DRY
CONDITIONS WITH MODERATING TEMPERATURES TUESDAY AFTERNOON INTO
WEDNESDAY. THURSDAY...MOIST SOUTHWESTERLY FLOW WILL DEVELOP OVER THE
REGION AHEAD OF A LOW PRESSURE SYSTEM APPROACHING FROM THE
MISSISSIPPI VALLEYS. INCREASING MOISTURE ALOFT WITH ISENTROPIC
LIFTING WILL GENERATE LIGHT PCPN OVER MUCH THE REGION BY THURSDAY
AND WILL BECOME MORE ACTIVE FRIDAY AS THE LOW ASSOCIATED WITH A COLD
FRONT CROSSES THE CAROLINAS. TEMPERATURES WILL REMAIN 7-10 DEGREES
BELOW NORMALS SUNDAY AND MONDAY...THEN STEADILY WARM THROUGH MID
WEEK.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
AT KCLT...A STRATO-CU DECK WILL DEVELOP WEST OF THE AIRFIELD THIS
AFTN. FEW-SCT CLOUDS UP AROUND 4500 FEET WILL AFFECT THE AIRFIELD AT
TIMES...BUT I DON/T THINK A DECK WILL DEVELOP THAT FAR EAST. WINDS
WILL BE LIGHT AND VARIABLE FOR A WHILE EARLY THIS AFTN...BECOMING
LIGHT OUT OF THE SOUTH BY MID AFTN. A LIGHT SLY COMPONENT TO THE
FLOW SHOULD THEN CONTINUE FOR THE REST OF THE TAF PERIOD.
AT HKY...A STRATO-CU DECK UP AROUND 4500 FEET IS EXPECTED TO DEVELOP
AT THE AIRFIELD A LITTLE LATER THIS AFTN...THEN LAST WELL INTO THE
EVENING HOURS. WINDS WILL BE LIGHT OUT OF THE SOUTH THROUGH THE
VALID PERIOD OF THE TAF.
AT KAVL...LIGHT NLY FLOW EXPECTED THROUGH TONIGHT. NO LOW CIG OR
VSBYS PROBLEMS EXPECTED WITH A DRY AIRMASS OVER THE REGION.
HOWEVER...A DECK UP AROUND 4500 FEET COULD AFFECT THE AIRFIELD LATER
IN THE AFTN. CONFIDENCE IS TOO LOW TO INCLUDE THIS IN THE TAF.
UPSTATE SITES...SCT-BKN CIGS UP AROUND 4000-4500 FEET WILL GRADUALLY
LIFT NORTH OF THE REGION BY LATE AFTN. WINDS WILL BE LIGHT AND
VARIABLE...GRADUALLY BECOMING LIGHT OUT OF THE SOUTH. A DECK UP
AROUND 120KFT IS EXPECTED TO MOVE IN AFTER SUNRISE TMRW.
OUTLOOK...A COLD FRONT WILL APPROACH FROM THE NORTHWEST ON FRIDAY
AND MOVE EAST OF THE REGION ON SATURDAY. THE BEST CHANCE OF
RESTRICTIONS WILL BE AT KAVL WITH FROPA AND JUST BEHIND IT EARLY
SATURDAY. DRY HIGH PRES WILL RETURN SUNDAY THROUGH MONDAY.
AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)...
WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM
&&
.FIRE WEATHER...
A CAUTIONARY NOTE FOR AGENCIES DOING CONTROLLED BURNS ACROSS THE
NORTH CAROLINA FOOTHILLS AND BLUE RIDGE TODAY. IF THE CLOUD COVER
THAT HAS STARTED TO DEVELOP OVER THE UPSTATE SPREADS NORTHWARD...AS
THE MODELS ARE ADVERTISING...TEMPERATURES WILL BE SLOWER TO
RISE...MIXING HEIGHTS WILL BE LOWER AND TRANSPORT WINDS WILL BE EVEN
LIGHTER THAN THE CURRENT FORECAST. PRESENT INDICATIONS ARE THAT THIS
WILL HAPPEN. IF YOU ARE ON THE FENCE ABOUT BURNING...IT/S BEST TO
HOLD OFF FOR TODAY.
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...JOH
NEAR TERM...MCAVOY
SHORT TERM...JAT
LONG TERM...JOH
AVIATION...MCAVOY
FIRE WEATHER...MCAVOY
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
131 PM MST THU FEB 9 2012
.DISCUSSION...A LARGE HUDSON BAY LOW WILL DOMINATE OUR WEATHER
THROUGH MUCH OF THE WEEKEND. BELOW AVERAGE TEMPERATURES WILL BE THE
RULE...WITH A SUBSTANTIAL LOW-LEVEL TEMPERATURE GRADIENT ACROSS THE
CWA. THE COLD AIR AND BAROCLINIC ZONE WILL HELP TO SQUEEZE OUT THE
LIMITED MOISTURE...WITH SOME SPOTS IN NERN WY SEEING A FEW INCHES OF
ACCUMULATION.
WILL LET WIND ADVISORY EXPIRE AS PLANNED AT 00Z. STRONG PRESSURE
RISES AND COLD ADVECTION SHOULD KEEP THE WINDS GOING UNTIL THEN.
UPPER JETS KISS OVER CWA TONIGHT AND INTENSIFY SLIGHTLY. THIS IS
FOLLOWED BY AN INFLUX OF COLDER AIR AND EVENTUALLY AN UPPER-LEVEL
TROUGH PASSAGE FRIDAY NIGHT AND SATURDAY MORNING. A STRONG...COLD
SURFACE HIGH PRESSURE ALSO WILL MOVE SOUTH ACROSS THE DAKOTAS ON
SATURDAY...BEHIND THE UPPER WAVE. AFTER THAT THE FLOW ALOFT BECOMES
WEAK...AND THUS AMENABLE TO SUBSTANTIAL LOW CLOUDS AND POSSIBLY SOME
FOG LATE SATURDAY THROUGH SUNDAY MRNG. LOW FROUDE FLOW THROUGH THE
PERIOD WILL PRECLUDE UPSLOPE SNOWS...BUT LOCAL ENHANCEMENT MAY OCCUR
IN THE NRN FOOTHILLS.
AN INITIAL SHOT OF LIGHT SNOW IS EXPECTED TONIGHT WITH THE LEADING
EDGE OF THE ARCTIC AIR...ESPECIALLY OVER NWRN THROUGH CNTRL SD. EVEN
THOUGH MOST MODELS HAVE NO INDICATION OF QPF...UPSTREAM OBS AND THE
HRRR AND RUC DO SUGGEST LIGHT SNOW SHOWERS MAY EVEN LINGER PAST 06Z
OVER MUCH OF THE SD PLAINS. OTHERWISE...THE BEST FORCING FOR UPWARD
MOTION WILL BE OVER NERN WY AND FAR SWRN SD FRIDAY AND FRIDAY NIGHT
AS TWO MORE JETS INTERACT. FRONTOGENESIS ALSO WILL BE ACTIVE ALONG
THE BAROCLINIC ZONE OVER NERN WY...AND THUS EXPECT A FEW INCHES OF
SNOWFALL. THE BAROCLINIC ZONE WILL BECOME SOMEWHAT DIFFUSE BY EARLY
SUNDAY...BUT IT STILL WILL RESIDE OVER THE SWRN CWA. THIS MAY
PROVIDE AN ADDITIONAL FOCUS FOR SNOW ON SUNDAY AS AN UPPER TROUGH
MOVES OVER THE FOUR CORNERS REGION.
LATEST MOS GUIDANCE HAS TRENDED COLDER WITH LOWS THE NEXT TWO DAYS.
WHILE THE TEMPS HAVE BEEN NUDGED LOWER...HAVE NOT GONE AS COLD AS
MOS...ESPECIALLY WHERE CLOUD COVER IS EXPECTED.
EXTENDED...UPPER LEVEL FLOW REMAINS NORTHWESTERLY OVER THE NORTHERN
PLAINS FOR EARLY NEXT WEEK. MEDIUM RANGE GUIDANCE CONTINUES TO SHOW
POOR AGREEMENT ON TIMING AND PLACEMENT OF SEVERAL WEAK SHORTWAVES
THAT CROSS THE AREA. REGARDLESS...ATMOSPHERE REMAINS FAIRLY DRY WITH
THIS REGIME. WILL CONTINUE WITH A DRY FORECAST. TEMPERATURES IN THIS
TYPE OF FLOW SHOULD REMAIN NEAR AVERAGE.
&&
.AVIATION...18Z TAFS UPDATE
STRONG NORTHWEST WINDS WILL SUBSIDE THROUGH THIS EVENING. MVFR CIGS
WILL SLIDE SOUTHWARD ACROSS NORTHWEST AND CENTRAL SOUTH DAKOTA THIS
EVENING...AND INTO WESTERN SOUTH DAKOTA AFTER 06Z. LIGHT SNOW IS
ALSO EXPECTED TO DEVELOP ACROSS PARTS OF NORTHEAST WYOMING AND FAR
WESTERN SOUTH DAKOTA THROUGH EARLY FRIDAY MORNING. ALONG WITH MVFR
CIGS...THE SNOWFALL WILL RESULT IN MVFR VSBY WITH LOCAL IFR
CONDITIONS POSSIBLE.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...WIND ADVISORY UNTIL 5 PM MST THIS AFTERNOON FOR BUTTE-HAAKON-
HARDING-NORTHERN MEADE CO PLAINS-PENNINGTON CO PLAINS-
PERKINS-RAPID CITY-SOUTHERN MEADE CO PLAINS-
STURGIS/PIEDMONT FOOT HILLS-ZIEBACH.
WY...NONE.
&&
$$
SHORT TERM...BUNKERS
LONG TERM....CALDERON
AVIATION...CALDERON
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
1056 PM CST WED FEB 8 2012
.DISCUSSION.../ISSUED AT 825 PM CST/
ONLY PROBLEM REMAINS STRATUS ON THE SOUTH END OF FORECAST AREA. IN
LIGHT OF SHORT TERM MODELS WILL CONTINUE TO PLAY IT TO PUSH SLOWLY
EAST AND SLIGHTLY INTO FORECAST AREA INCLUDING YANKTON TO ESPECIALLY
SIOUX CITY. HRRR TRIES TO DEVELOP IT NORTHEAST LATE TO THE AREA FROM
FSD NORTH AND EAST BUT WITH NO SNOW COVER AND ADVANCING DRY AIR AND
SUBSIDENCE...THINK IT WILL STAY OUT OF ALL BUT THE FAR SOUTH. THIS
MODEL TRIED TO DEVELOP SUCH A SEPARATE AREA A FEW NIGHTS AGO WITH
THE LOWER STRATUS AND FOG IN THE DRY AIR TOO FAR NORTH AND THAT
FAILED TO DEVELOP. SO FOR THE AREA EXCEPT THE FAR SOUTH CLEAR SHOULD
CONTINUE. TEMPERATURES LOOK OK WITH THE LIGHT WARMING LOW LEVEL
FLOW PREVENTING A DROP WELL DOWN INTO THE SINGLE DIGITS AS WE HAD
LAST NIGHT. / WILLIAMS
&&
.AVIATION.../FOR THE 06Z TAF ISSUANCE/
06Z TAFS WILL REFLECT MVFR STRATUS MOVING THROUGH KSUX AFTER
MIDNIGHT. A BIT OF STRATUS CONTINUES TO MOVE EASTWARD...EDGING ALONG
OUR FAR SOUTHERN ZONES...AND WILL LIKELY IMPACT KSUX FROM ABOUT
0630Z THROUGH AROUND 1000Z. OTHERWISE CONDITIONS WILL BE VFR UNTIL
THIS EVENING. A STRONG COLD FRONT WILL MOVE SOUTHWARD ACROSS THE FSD
FORECAST AREA LATE THIS AFTERNOON AND EVENING. BEHIND THE FRONTAL
PASSAGE...THE LATEST NAM IS SHOWING MVFR STRATUS TO BE MOVING
SOUTHWARD ALONG WITH THE STRONG COLD AIR ADVECTION. THIS IS
REASONABLE. IT WILL BE CLOSE WHETHER ANY MVFR STRATUS MAKES IT AS
FAR SOUTH AS KSUX BY 06Z/10 HOWEVER. /MJF
&&
.PREV DISCUSSION.../ISSUED AT 316 PM CST/
STRATUS CONTINUES TO NIP AT THE SOUTHERN BORDER OF THE CWA THIS
AFTERNOON AND EXPECT THIS TREND TO CONTINUE THROUGH THE NIGHT. WHILE
THE NORTHERN EDGE IS DISSIPATING...EXPECT THAT A RESURGENCE TO THE
NORTH WILL OCCUR TONIGHT AS THE INVERSION STRENGTHENS AND THE WINDS
REMAIN LIGHT SOUTH TO SOUTHWEST WHICH SHOULD AID IN ADVECTING TO THE
EAST AND NORTHEAST. FOR NOW WILL KEEP NEAR AND ALONG THE MISSOURI
RIVER BUT THIS WILL NEED TO BE WATCHED AS IT COULD CREEP NORTHWARD
AHEAD OF DEVELOPING WEST WINDS FOR THURSDAY. OTHERWISE...DID NOT
CHANGE LOWS TOO MUCH...JUST WARMED A BIT IN THE SOUTH WITH THE
POTENTIAL STRATUS...BUT MAINLY TEENS.
STILL PLANNING ON A MILD AND NOT TOO BREEZY DAY THURSDAY AHEAD OF
THE NEXT COLD FRONT. WEST WINDS SHOULD AVERAGE ABOUT 15 TO 20 MPH.
LOW LEVEL THERMAL FIELD NOT TOO IMPRESSIVE HOWEVER SO WARMEST HIGHS
LIKELY ONLY INTO THE MID 40S...BUT STILL 15 DEGREES OR SO ABOVE
NORMAL. /08
COLD FRONT EXITS THE FORECAST AREA ON THURSDAY NIGHT WITH A SURGE OF
MUCH COLDER AIR ARRIVING LATE AT NIGHT AND INTO FRIDAY. BRISK NORTH
WINDS ARE EXPECTED BEHIND THE FRONT...TURNING NORTHEASTERLY ON
FRIDAY BEFORE GRADUALLY DIMINISHING THROUGH THE DAY. DRY WEATHER
WILL PREVAIL WITH ONLY SOME INCREASED CLOUD COVERAGE FOLLOWING THE
FRONT. LOWS WILL FALL MAINLY INTO THE SINGLE DIGITS FOLLOWED BY
HIGHS ONLY RECOVERING INTO THE LOWER TEENS IN THE NORTHEAST TO NEAR
20 INTO THE MO VALLEY. FRIDAY NIGHT AND SATURDAY WILL PAINT A
SIMILAR PICTURE AS ARCTIC HIGH PRESSURE GRADUALLY SINKS SOUTHWARD
FROM CANADA AND SITS OVERHEAD BY SATURDAY AFTERNOON.
RIDGING BUILDS INTO THE CENTRAL STATES ON SUNDAY WITH THE SURFACE
HIGH SINKING SOUTHEAST OF THE CWA. THE RESULTANT RETURN FLOW WILL
ALLOW SOME WARMING OF THE AIRMASS AND TEMPERATURES TO RETURN TO NEAR
NORMALS IN THE UPPER 20S. A MID LEVEL SHORTWAVE FOLLOWS SUNDAY NIGHT
THROUGH MONDAY WHICH INTRODUCES A CHANCE FOR LIGHT SNOWFALL MAINLY
EAST OF I29. WITH BOTH THE GFS AND ECMWF SHOWING SOME DECENT FORCING
NEAR OUR SOUTHERN AND EASTERN BORDER...WENT AHEAD AND BUMPED UP POPS
ABOUT 10 PERCENT HIGHER THAN THE ALLBLEND.
NEAR SEASONAL TO SLIGHTLY ABOVE NORMAL TEMPERATURES ARE EXPECTED FOR
EARLY NEXT WEEK. MODELS A BIT UNCERTAIN ABOUT A POTENTIAL CUT OFF
LOW WHICH IS NOW TRENDING WELL SOUTH OF THE FORECAST AREA. GIVEN THE
LARGE CHANGE FROM THE PREVIOUS MODEL RUNS...LEFT SOME SLIGHT CHANCE
POPS FROM THE ALLBLEND IN FOR TUESDAY NIGHT AND WEDNESDAY.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1137 PM EST WED FEB 8 2012
.SYNOPSIS...
LOW PRESSURE OFFSHORE THE OUTER BANKS WILL CONTINUE TO MOVE EAST
AND OFFSHORE OVERNIGHT. HIGH PRESSURE BUILDS IN FOR THURSDAY AND
MUCH OF FRIDAY BEFORE AN ARCTIC COLD FRONT CROSSES THE
APPALACHIANS FRIDAY NIGHT INTO SATURDAY BRINGING MOUNTAIN SNOW
SHOWERS ALONG WITH MUCH COLDER AIR. HIGH PRESSURE FOLLOWS THE
FRONT WITH DRIER AIR AND A SLOW MODERATION IN TEMPERATURES FOR
EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH THURSDAY/...
AS OF 830 PM EST WEDENSDAY...
EVENING SOUNDINGS SHOW THE FLOW TURNING MORE UPSLOPISH TONIGHT WITH
RATHER DEEP MOISTURE UNDER THE INVERSION UP TO NEAR 7H. HOWEVER
DESPITE THE COLUMN BEING BELOW FREEZING...MOISTURE ON THE WESTERN
SLOPES HAS BECOME A BIT MORE SHALLOW ALLOWING THE FORMATION OF
MORE FREEZING DRIZZLE AND SNOW GRAINS THIS EVENING. HOWEVER PRECIP
COVERAGE REMAINS RATHER LIMITED GIVEN THE FLOW STILL A BIT TOO
WESTERLY AND BETTER MOISTURE BASICALLY CUT OFF TO THE EAST WITH
THE LOW OFFSHORE. LATEST LOCAL RNK WRF AND RUC ALSO DEPICTS MUCH LESS
UPSLOPE -SHSN COVERAGE AFTER MIDNIGHT WITH THE 85H FLOW TURNING
MORE NORTHERLY. THUS TRIMMED BACK TO LOW CHANCE POPS LATER
TONIGHT MAINLY FAR NW AFTER CURRENT SMALL BANDS FADE THIS EVENING.
ALSO INCLUDING A PERIOD OF SOME LIGHT MIX BASED ON SPOTTER REPORTS
FROM AROUND BLF AND OFF AND ON REPORTING OF UP/-FZRA IN OBS FROM
OUT WEST. WILL ALSO KEEP IN SOME ISOLATED -SHSN MENTION AS FAR
EAST AS THE NEW RIVER VALLEY THRU LATE THIS EVENING BEFORE DRYING
ALOFT WINS OUT. CLOUDS REMAIN SLOW TO GO ACROSS THE SOUTH/EAST AND
WITH MODELS TOO FAST TO ERODE VIA DOWNSLOPE...KEPT LOW CLOUDS IN
FOR A FEW MORE HOURS...WITH A GRADUAL EROSION BACK TO ALONG THE
BLUE RIDGE EXPECTED AFTER MIDNIGHT. BACKED OFF LOWS A LITTLE
ESPCLY WHERE CLOUDS LIKELY TO PERSIST LONGER ON HOLD TEMPS UP SOME
DESPITE WEAK COLD ADVECTION OVERNIGHT. SPS ALSO OUT TO MAKE
MENTION OF ICY SPOTS DUE TO CURRENT LIGHT PRECIP AND OVERNIGHT
BLACK ICE FROM EARLIER MELTING AND REFREEZING.
AS OF 300 PM EST WEDNESDAY...
WITH THIS MORNING`S DISTURBANCE PASSING EAST...MUCH OF THE
SNOW/RAIN IS FINISHED. HOWEVER...WINDS VEER MORE TO THE NW SOMEWHAT
ACROSS SE WEST VA AND ANOTHER SHRTWV APPROACHES FROM IN/IL THIS
EARLY EVENING. SNOW SHOWERS ARE POSSIBLE IN THE LWB/BLF CORRIDOR
WITH THIS WAVE...AND MAY BE SOME FLURRIES INTO THE NEW RIVER
VALLEY AND NW NC. AFTER MIDNIGHT...WINDS DECREASE SUCH THAT ONLY
CLOUDS AND A SNOW SHOWER ACROSS WESTERN GREENBRIER IS EXPECTED.
THE AFOREMENTIONED DISTURBANCE COULD PUT DOWN A FRESH COATING AT
BLF/LWB...AND MAYBE AN INCH OR TWO IN WESTERN GREENBRIER. SNOW MAY
BEGIN TO STICK TO ROADS WITH TEMPS FALLING INTO THE 20S AND ROADS
WHICH ARE NOW WET MAY DEVELOP ICY PATCHES. ALTHOUGH THE GROUND IS
STILL RATHER WARM AND THIS IS NOT GOING TO BE A FLASH FREEZE.
WINDS MAY GUST TO 30 MPH EARLY TONIGHT IN NW NC. OVERCAST WILL
HOLD ALONG THE HIGHLANDS OF SE WEST VA THURSDAY...THEN CLEAR BY
LATE MORNING WITH PLENTY OF SUNSHINE AND HIGHS IN THE LOW TO UPPER
40S...A FEW DEGREES BELOW GUIDANCE.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
AS OF 230 PM EST WEDNESDAY...
HIGH PRESSURE CONTINUES TO MOVE EAST THURSDAY NIGHT INTO FRIDAY.
FLOW AROUND THE HIGH WILL RESULT IN WESTERLY WINDS FOR OUR REGION.
LOW TEMPERATURES THURSDAY NIGHT WILL BE NEAR NORMAL WITH READINGS
FROM THE UPPER TEENS IN THE NORTHWEST MOUNTAINS TO THE UPPER 20S IN
THE PIEDMONTS.
MOISTURE INCREASES ON FRIDAY IN ADVANCE OF AN APPROACHING COLD
FRONT. PLAYED HIGHS ON FRIDAY CLOSE TO ADJMETBC WITH READINGS
FROM THE MID 30S IN THE NORTHWEST MOUNTAINS TO THE MID 50S IN THE
SOUTHEAST. THE COLD FRONT WILL MOVE ACROSS THE AREA FRIDAY NIGHT
BRINGING SCATTERED RAIN/SNOW SHOWERS TO THE MOUNTAINS...WITH MAINLY
SPRINKLES/FLURRIES EAST OF THE BLUE RIDGE. SNOWFALL AMOUNTS WILL
GENERALLY BE LESS THAN AN INCH OR TWO. THE HIGHEST SNOW AMOUNTS WILL
FALL IN WESTERN GREENBRIER COUNTY. LOW TEMPERATURES FRIDAY NIGHT
WILL RANGE FROM THE UPPER TEENS IN THE NORTHWEST MOUNTAINS TO THE
MID 30S IN SOUTHSIDE.
ON SATURDAY...PREVAILING NORTHWEST FLOW WILL HELP MAINTAIN SNOW
SHOWERS AND SNOW FLURRIES ACROSS THE MOUNTAINS. ADDITIONAL SNOWFALL
AMOUNTS UP TO AN INCH ARE POSSIBLE. 85H WINDS ON THE GFS AND ECMWF
ARE PROGGED TO BE IN THE 35 TO 40 KT RANGES ACROSS THE WEST. WE MAY
SEE SOME SURFACE GUSTS UP TO 35 MPH AT HIGHER ELEVATIONS. THE
PRESSURE RISES ON THE ECMWF ARE NOTEWORTHY. WINDS SHOULD REMAIN
BELOW ADVISORY LEVELS ACROSS THE HIGHEST ELEVATIONS. COLD AND
WINDY ON SATURDAY WITH HIGHS FROM THE MID 20S IN THE WEST TO MID 40S
IN THE EAST. THE SNOW SHOWERS AND SNOW FLURRIES WILL GRADUALLY
DECREASE IN COVERAGE AND END SATURDAY AFTERNOON INTO SATURDAY NIGHT.
LOWERED MINIMUM TEMPERATURES FOR SATURDAY NIGHT FROM THE SINGLE
DIGITS TO THE LOWER 20S IN THE SOUTHEAST. WIND CHILLS BELOW ZERO ARE
POSSIBLE IN THE HIGHEST ELEVATIONS OF THE NORTHWEST MOUNTAINS.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 237 PM EST WEDNESDAY...
AFTER A BREEZY SUNDAY MORNING...COLD HIGH PRESSURE WILL BUILD INTO
THE REGION. THIS RIDGE SLIDES OFF THE MID ATLANTIC COAST MONDAY
NIGHT. A FEW SHOWERS MAY ACCOMPANY A WARM FRONT ON TUESDAY. A COLD
FRONT APPROACHES FROM THE WEST ON WEDNESDAY TO INCREASE SHOWERS
CHANCES.
TEMPERATURES SUNDAY WILL BE BLUSTERY AND 10F-15F BELOW NORMAL.
TEMPERATURES MODERATE TOWARD SEASONAL LEVELS ON MONDAY. THE PASSING
OF THE WARM FRONT TUESDAY WILL ALLOW TEMPERATURES TO WARM INTO THE
UPPER 40S TO LOWER 50S. BEING AHEAD OF A COLD FRONT
WEDNESDAY...TEMPERATURES COULD JUMP 10-15F ABOVE NORMAL.
&&
.AVIATION /04Z THURSDAY THROUGH MONDAY/...
AS OF 1115 PM EST WEDNESDAY...
SCATTERED VERY LIGHT SNOW SHOWERS AND/OR FREEZING DRIZZLE WILL
CONTINUE AT TIMES ACROSS THE UPSLOPE AREAS OF SE WVA INTO THE
EARLY MORNING HOURS BUT REMAIN PRIMARILY WEST OF THE TAF SITES.
THE UPSLOPE NW FLOW WILL RESULT IN PERSISTENT MVFR/IFR CIGS AT
KBLF/KLWB OVERNIGHT INTO EARLY THU...AND PERIODIC MVFR AT KBCB
WITH MAINLY VFR CIGS FROM KROA AND POINTS EAST OVERNIGHT UNTIL
CLOUDS FADE LATE. AN INTERMITTENT VSBY REDUCTION REMAINS POSSIBLE
AROUND KBLF OVERNIGHT IN -SHSN BANDS BUT TOO IFFY TO INCLUDE AT
THIS POINT SO KEEPING VFR VSBYS. MAY ALSO SEE SOME PATCHY FOG
DEVELOP OUT EAST AS SKIES CLEAR AND WINDS LIGHTEN SOME BUT ALSO
LOW CONFIDENCE SO ONLY INCLUDING A MENTION AT KLYH. NW WINDS WILL
REMAIN GUSTY FOR A FEW MORE HOURS OVERNIGHT BUT THEN START TO
DIMINISH WELL BEFORE DAYBREAK THURSDAY AS HIGH PRESSURE BUILDS IN.
ANY FLURRIES END THURSDAY MORNING AT KBLF/KLWB...WITH CIGS BECOMING
BKN AND RISING ABV 3KFT PERHAPS BY MID MORNING. OTRW SHOULD RETURN
TO WIDESPREAD VFR THURSDAY AFTERNOON INTO FRIDAY...BEFORE AN
ARCTIC COLD FRONT PRODUCES SNOW SHOWERS AND BRINGS MVFR/IFR
RESTRICTIONS TO KLWB/KBLF FRIDAY NIGHT THROUGH LATE SAT. A PERIOD
OF MVFR CIGS AND VSBYS ALSO POSSIBLE LATER FRIDAY NIGHT AT KBCB
AND POSSIBLY KROA WITH VFR CIGS OUT EAST. HIGH PRESSURE AND VFR
RETURNS SUNDAY AND MONDAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...JH/KM
NEAR TERM...JH/KM
SHORT TERM...KK
LONG TERM...RCS
AVIATION...AMS/JH/KM
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
215 PM CST THU FEB 9 2012
.SHORT TERM...TONIGHT THROUGH SUNDAY
215 PM CST THU FEB 9 2012
MAIN FORECAST CONTINUES TO BE FOCUSED ON ARCTIC FRONTAL PASSAGE
TONIGHT AND ASSOCIATED SNOW SHOWER/FLURRY ACTIVITY INTO FRIDAY.
COLDER AIR MASS THROUGH THIS WEEKEND ALONG WITH WIND EXPECTED TO
PRODUCE SOME CHILLIER THAN NORMAL TEMPERATURES AND VERY COLD WIND
CHILLS...ESPECIALLY ON SATURDAY MORNING.
CURRENT SURFACE MAP THIS AFTERNOON HAS THE ARCTIC FRONTAL BOUNDARY
OOZING SOUTHWARD ACROSS NORTHERN MN/ND. VISIBLE SATELLITE SHOWING A
PATCH OF CUMULUS/STRATOCUMULUS ACROSS MOST OF NORTHEAST IA AND
PORTIONS OF SOUTHEAST MN INTO FAR SOUTHWEST WI. OTHERWISE...
SOUTHWEST WINDS AHEAD OF THIS FRONTAL BOUNDARY WAS PRODUCING
TEMPERATURES IN THE UPPER 20S TO LOWER 30S ACROSS THE FORECAST AREA.
HOWEVER...WIND CHILLS WERE MAKING IT FEEL MORE LIKE THE TEENS AND
20S.
09.12Z MODELS IN GOOD AGREEMENT THROUGH THE SHORT TERM.
WATER VAPOR IMAGERY/RUC ANALYSIS SHOWING A FAIRLY STRONG MID-LEVEL
SHORTWAVE TROUGH ROTATING SOUTHEASTWARD THROUGH
ONTARIO/MANITOBA/SASKATCHEWAN THIS AFTERNOON. THIS WILL DRIVE THE
ARCTIC FRONT THROUGH THE AREA OVERNIGHT...EXITING SOUTH OF THE AREA
BY DAYBREAK. MODELS CONTINUE TO SHOW RATHER VIGOROUS FORCING WITH
THE FRONT WITH GOOD 850-300MB PV-ADVECTION/STEEPENING LOW LEVEL
0-1KM LAPSE RATES FOR SCATTERED SNOW SHOWERS. HIGHEST PROBABILITIES
FOR THE SNOW SHOWER ACTIVITY APPEARS TO ALONG AND NORTH OF THE I-94
CORRIDOR AFTER MIDNIGHT WITH FLURRY ACTIVITY FILLING IN ELSEWHERE.
COULD SEE A FEW TENTHS OF AN INCH OF SNOWFALL OUT OF THE MORE
VIGOROUS SNOW SHOWERS. OTHERWISE...LOOK FOR LOWS TOWARD MORNING
FALLING INTO THE SINGLE DIGITS AND TEEN ALONG WITH INCREASING NORTH
WINDS. COLDEST WIND CHILL VALUES TOMORROW MORNING SHOULD RANGE FROM
THE SINGLE DIGITS ACROSS FAR SOUTHWEST WISCONSIN...TO THE SINGLE
DIGITS AND TEENS BELOW ZERO ACROSS THE REST OF THE AREA.
MUCH COLDER CYCLONIC FLOW WILL LINGER ACROSS THE AREA FRIDAY WITH
CONTINUED VERY STEEP LOW LEVEL 0-1KM LAPSE RATES. THIS WILL BE
ENOUGH TO CONTINUE GENERATING FLURRIES. WITH 925MB TEMPERATURES
PLUMMETING INTO THE TEEN BELOW 0C...LOOK FOR HIGHS TO TOP OFF ONLY
IN THE 10-20 DEGREE RANGE. ADDING NORTH WINDS OF 10-25 MPH WILL
YIELD WIND CHILLS IN THE SINGLE DIGITS ABOVE AND BELOW ZERO.
CLEARING SKIES EXPECTED FRIDAY NIGHT AS HIGH PRESSURE BUILDS
SOUTHEAST OUT OF THE CENTRAL CANADIAN PROVINCES INTO THE NORTHERN
PLAINS/UPPER MISSISSIPPI RIVER REGION. TEMPERATURES DROPPING INTO
THE SINGLE DIGITS ABOVE/BELOW ZERO AND NORTH WINDS AROUND 10 MPH ARE
EXPECTED TO PRODUCE SOME FRIGID WIND CHILLS IN THE TEENS/LOWER 20S
BELOW ZERO. MAY HAVE TO KEEP A WATCH FOR POTENTIAL WIND CHILL
HEADLINES LATE FRIDAY NIGHT/EARLY SATURDAY MORNING.
SATURDAY EXPECTED TO BE SUNNY BUT REMAINING VERY CHILLY AS HIGH
PRESSURE SLIDES DOWN THROUGH THE PLAINS. THIS KEEPS A FAIRLY TIGHT
PRESSURE GRADIENT ACROSS OUR AREA WITH FAIRLY BRISK WEST/NORTHWEST
WINDS CONTINUING. HIGHS ARE ONLY EXPECTED TO TOP OFF IN THE TEENS
ONCE AGAIN WITH WIND CHILLS HOVERING IN THE SINGLE DIGITS
ABOVE/BELOW ZERO RANGE.
MOSTLY CLEAR SKIES EXPECTED SATURDAY NIGHT THROUGH SUNDAY AS
THE RIDGE AXIS SLOWLY BUILDS EAST OVER THE AREA. SOME MODERATION IN
TEMPERATURES ALSO EXPECTED WITH LOWS SATURDAY NIGHT IN THE SINGLE
DIGITS ABOVE ZERO AND HIGHS ON SUNDAY IN THE 20S.
.LONG TERM...SUNDAY NIGHT THROUGH THURSDAY
215 PM CST THU FEB 9 2012
09.12Z GFS AND ECMWF IN GENERALLY GOOD AGREEMENT THROUGH
TUESDAY...BUT THEN DIVERGE A BIT AFTER THAT. BOTH MODELS SHOWING
GOOD RUN TO RUN CONTINUITY WITH A WEAK MID-LEVEL TROUGH APPROACHING
THE AREA SUNDAY NIGHT/MONDAY. GFS SHOWS PRETTY DECENT 275-280K LAYER
ISENTROPIC LIFT LATE SUNDAY NIGHT INTO MONDAY AHEAD OF THIS TROUGH.
MAY HAVE TO OVERCOME RESIDUAL FAIRLY DRY LOWER LEVELS AS RIDGE AXIS
DEPARTS EAST OF THE AREA. FOR NOW...WILL CARRY SMALL-END SLIGHT
CHANCE OF -SN ACROSS NORTHEAST IA/SOUTHEAST MN SUNDAY NIGHT AND GO
WITH HIGH-END CHANCE POPS/LIKELY POPS SOUTH OF I-90 ON MONDAY AS THE
TROUGH CONTINUES TO PUSH EAST ACROSS IA/IL/SOUTHERN WI. PRELIMINARY
INDICATIONS ARE THAT THE AREA COULD SEE 1-2 INCHES SOUTH OF
I-90...TAPERING OFF TO PERHAPS A DUSTING NORTHEAST IF I-94.
TUESDAY/TUESDAY NIGHT LOOK DRY FOR NOW AS AS A WEAK RIDGE MOVES
ACROSS THE UPPER MISSISSIPPI RIVER REGION. AS STATED BEFORE...MODELS
GET KIND OF SKETCHY FOR WEDNESDAY/THURSDAY DEALING WITH VARIOUS
ENERGY IN SPLIT FLOW REGIME ACROSS CANADA/CONUS. THE GFS WANTS TO
EJECT A TROUGH NORTHEAST OUT OF THE ROCKIES AND INTO THE REGION
WED/WED N FOR A CHANCE OF LIGHT SNOW WHILE THE ECMWF KEEPS THE AREA
DRY UNDER GENERAL RIDGING. WILL GO WITH A BLEND FOR NOW WITH A VERY
SLIGHT CHANCE OF -SN IN THE GRIDS.
&&
.AVIATION...THROUGH 18Z FRIDAY
1127 AM CST THU FEB 9 2012
A LARGE AREA OF STRATUS WAS LOCATED OVER SOUTHERN IOWA AT
17Z...WITH THE NORTHERN EXTENT EXTENDING INTO NORTHEAST IOWA AND
FAR SOUTHEAST MINNESOTA. MEANWHILE...A COLD FRONT WAS STRETCHED
FROM JUST NORTH OF LAKE SUPERIOR...INTO NORTHERN MINNESOTA. 09.14Z
HRRR ALONG WITH THE 09.15Z RUC DOES SHOW THE STRATUS OVER
NORTHEAST IOWA TO SKIRT ALONG THE TAF SITES THIS AFTERNOON. DID
MENTION A SCATTERED DECK AT BOTH SITES...BUT FEEL CEILINGS WILL BE
SOUTH OF THE AREA. IF CEILINGS DO DEVELOP THEY WILL BE SHORT
LIVED...ESPECIALLY AT KRST. ANY CEILINGS THAT DO DEVELOP WOULD BE IN THE
MVFR CATEGORY. NEXT CONCERN IS ON ARCTIC BOUNDARY THAT WILL PUSH
ACROSS THE TAF SITES LATER TONIGHT. WINDS WILL SWITCH AROUND TO A
WEST THEN NORTHWEST DIRECTION BETWEEN 06Z-09Z WITH SPEEDS
INCREASING AND SOME GUSTS TO 20 TO 23 KNOTS. MVFR STRATUS IS
EXPECTED BEHIND THE FRONT WHICH WILL CONTINUE THROUGH 18Z FRIDAY.
COULD ALSO BE SOME -SHSN...BUT DID NOT BRING ANY RESTRICTIONS TO
VISIBILITY WITHIN THE -SHSN.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
215 PM CST THU FEB 9 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM....DAS
AVIATION...RABERDING
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1234 PM CST THU FEB 9 2012
.UPDATE...
TRACKING AREA OF STRATUS CLOUDS THAT MOVED FROM NORTH CENTRAL IOWA
AT 8 AM TO FAR SOUTHWEST WI AROUND NOON TODAY. EXPECTING THE LEADING
EDGE TO SLOW DOWN AND BECOME A LITTLE FUZZY AS IT MOVES EAST DUE TO
MIXING. HOWEVER THE CLOUD TRENDS ARE SHOWING A SOLID LAYER OF
MOISTURE TRAPPED BELOW THE INVERSION OF AROUND 4000 FEET THAT IS
REALLY NOT MIXING OUT DUE TO MIXING ONLY UP TO AROUND 2000 FEET. LOW
CONFIDENCE ON EXACT COVERAGE OF CLOUDS THROUGH THE REST OF THE
AFTERNOON...BUT TIMING OF THE LEADING EDGE BRINGS THEM INTO MADISON
AROUND 2 TO 3 PM. HRRR MARCHES THE STRATUS CLOUDS ACROSS ALL OF
SOUTHERN WI AT A STEADY RATE THIS AFTERNOON...REACHING MILWAUKEE
AROUND 7 PM. IF THE CLOUDS SPREAD ACROSS SOUTHERN WI...THERE SHOULD
BE NO REASON FOR THEM TO LEAVE UNTIL WELL AFTER THE COLD FRONT
PASSES THROUGH.
GIVEN THE LATE ARRIVAL OF THE CLOUDS TODAY...WE SHOULD STILL BE ABLE
TO WARM UP TO THE EXPECTED HIGH TEMPERATURES TODAY...SO WILL NOT BE
MAKING ANY BIG CHANGES. IF CLOUDS STICK AROUND TONIGHT...WE SHOULD
HAVE WARMER THAN EXPECTED LOW TEMPS...SO WILL BE TAKING THIS INTO
CONSIDERATION.
TIGHT PRESSURE GRADIENT ACROSS WISCONSIN DUE TO LOW PRESSURE OVER
SOUTHERN ONTARIO AND HIGH PRESSURE OVER THE KENTUCKY AREA.
WEST-SOUTHWEST WINDS ARE INCREASING THIS AFTERNOON...WITH GUSTS TO
AROUND 20 KNOTS.
&&
.AVIATION/18Z TAFS/...
SOUTHWEST FLOW AND TRAPPED LOW LEVEL MOISTURE IS BRINGING AN AREA OF
MVFR STRATUS FROM NORTHEAST IOWA INTO SOUTHERN WI THIS AFTERNOON AND
EARLY EVENING. TIMING OF SATELLITE TRENDS WOULD BRING THE LEADING
EDGE OF THE CLOUD DECK INTO MSN AROUND 3 PM AND HRRR MODEL TIMING
BRINGS IT INTO MKE AROUND 7 PM. IF THIS CLOUD DECK MAKES IT INTO
SOUTHERN WI BY EARLY EVENING...THERE WILL BE NOTHING TO SCOUR IT OUT
DUE TO THE LOW LEVEL INVERSION OVERNIGHT. THE CLOUDS WILL STAY IN
THE REGION UNTIL WELL AFTER THE COLD FRONT CLEARS SOUTHERN
WI...THROUGH AT LEAST FRIDAY AFTERNOON.
THERE IS A GOOD CHANCE FOR SNOW SHOWERS JUST BEHIND THE COLD FRONT
FRIDAY MORNING THROUGH FRIDAY AFTERNOON. NOT EXPECTING HIGH
ACCUMULATIONS...ALTHOUGH LAKE ENHANCED SNOW COULD BRING SLIGHTLY
HIGHER ACCUMS TO THE LAKESHORE AREAS. TOTAL SNOWFALL AMOUNTS SHOULD
BE GENERALLY AROUND A HALF INCH...BUT UP TO 1.5 INCHES AT MKE RAC
ENW. STRONG AND GUSTY NORTH WINDS WILL ACCOMPANY THE SNOW SHOWERS ON
FRIDAY. MVFR VSBY WITH OCCASIONAL IFR VSBYS POSSIBLE.
&&
.MARINE...
INCREASING SOUTHWEST WINDS TODAY AND EARLY TONIGHT WILL APPROACH
SMALL CRAFT ADVISORY CONDITIONS. SMALL CRAFT ADVISORIES ARE IN
EFFECT FOR ALL OF THE SHORE AREAS FRIDAY MORNING INTO FRIDAY NIGHT
BEHIND A STRONG COLD FRONT. THE GUSTY NORTH WINDS WILL CREATE HIGH
WAVES FRIDAY...LASTING INTO SATURDAY.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY FROM 9 AM FRIDAY TO 3 PM CST SATURDAY FOR
LMZ645-646.
SMALL CRAFT ADVISORY UNTIL NOON CST SATURDAY FOR LMZ643-644.
&&
$$
UPDATE...MRC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1127 AM CST THU FEB 9 2012
.SHORT TERM...TODAY THROUGH SATURDAY NIGHT
250 AM CST THU FEB 9 2012
MAIN FORECAST CONCERNS ARE ON LIGHT SNOW/FLURRY CHANCES TONIGHT
THROUGH FRIDAY AND HIGH TEMPERATURES FRIDAY INTO SATURDAY BEHIND
THE ARCTIC COLD FRONT.
CURRENT SURFACE OBSERVATIONS SHOWED A COLD FRONT EXTENDING FROM
CENTRAL ONTARIO WEST THROUGH SOUTHERN MANITOBA INTO SOUTHERN
SASKATCHEWAN. THE FRONT WAS MOVING SOUTH EARLY THIS MORNING. AN
AREA OF STRATUS WAS NOTED ACROSS EASTERN NEBRASKA/SOUTHWEST
IOWA...MOVING EAST AND SLIGHTLY NORTHEAST. WILL HAVE TO KEEP A
CLOSE WATCH ON THIS AREA OF STRATUS AS SOUTHWEST WINDS INCREASE
AHEAD OF THE FRONT THIS MORNING INTO THIS AFTERNOON WITH THE
POSSIBILITY OF THE STRATUS ADVECTING INTO THE FORECAST AREA.
HIGH PRESSURE WILL SLIDE SOUTH OF THE REGION TODAY AS THE ARCTIC
COLD FRONT APPROACHES THE REGION. THE HRRR DEVELOPS AN AREA OF
STRATUS ACROSS SOUTHWEST/SOUTH CENTRAL MINNESOTA INTO NORTHEAST IOWA
LATE THIS MORNING...WITH THE STRATUS SPREADING EAST OF THE
MISSISSIPPI RIVER THIS AFTERNOON. FORECAST SOUNDINGS ACROSS
SOUTH CENTRAL MINNESOTA AND NORTHEAST IOWA SHOW VERY DRY AIR IN
THE LOWER LEVELS OF THE ATMOSPHERE LATE THIS MORNING INTO THIS
AFTERNOON. SURFACE DEWPOINTS ACROSS THIS AREA ARE ONLY IN THE
SINGLE DIGITS TO LOWER TEENS WITH THE ONLY APPRECIABLE LOW LEVEL
MOISTURE NOTED IN THE AREA OF STRATUS ACROSS EASTERN NEBRASKA INTO
SOUTHWEST IOWA. PLAN ON MOSTLY SUNNY SKIES THROUGH EARLY AFTERNOON
WITH CLOUDS INCREASING DURING THE LATE AFTERNOON AND EARLY EVENING
HOURS AS THE COLD FRONT MOVES INTO THE FORECAST AREA. THE FRONT IS
EXPECTED TO BE POSITIONED FROM WESTERN LAKE SUPERIOR INTO
SOUTHWEST MINNESOTA BY 6 PM THIS EVENING. LOOK FOR THE FRONT TO
SWEEP ACROSS THE AREA DURING THE EVENING HOURS. THE BEST FORCING
FOR PRECIPITATION APPEARS TO BE RIGHT ALONG AND SLIGHTLY TRAILING
THE COLD FRONT. WOULD EXPECT TO SEE A FEW FLURRIES OR LIGHT SNOW
SHOWERS THIS EVENING INTO THE OVERNIGHT HOURS AS THE FRONT MOVES
THROUGH. NAM FORECAST SOUNDINGS SHOW THE POTENTIAL FOR SNOW
SHOWERS...MAINLY EAST OF THE MISSISSIPPI RIVER TONIGHT. THE GFS
SHOWS A BRIEF WINDOW OF FLURRIES/LIGHT SNOW SHOWERS THIS EVENING
BEFORE DRY/COLD AIR MOVES IN. A BRIEF SHOT OF ISENTROPIC LIFT
NOTED IN THE LATEST NAM SOLUTION ON THE 270 THROUGH 280 K SURFACES
THIS EVENING WITH CONDENSATION PRESSURE DEFICITS LOWERING TO
AROUND 7 MB WITHIN THIS LAYER. IF LIGHT SNOW DEVELOPS...LITTLE OR
NO ACCUMULATION IS EXPECTED WITH THIS ACTIVITY. WILL INCLUDE A
SLIGHT CHANCE OF VERY LIGHT SNOW ACROSS SOUTHEAST
MINNESOTA...NORTHEAST IOWA INTO SOUTHWEST AND CENTRAL WISCONSIN.
SLIGHTLY HIGHER CHANCES FOR SNOW ACROSS NORTH CENTRAL WISCONSIN.
OTHERWISE...PLAN ON MOSTLY CLOUDY SKIES OVERNIGHT WITH LOW
TEMPERATURES RANGING FROM THE SINGLE DIGITS BELOW ZERO ACROSS
NORTH CENTRAL WISCONSIN TO THE UPPER TEENS ACROSS PORTIONS OF
NORTHEAST IOWA INTO FAR SOUTHWEST WISCONSIN.
AN UPPER LEVEL TROUGH IS EXPECTED TO PUSH INTO THE AREA ON
FRIDAY...WITH PV15 SURFACES DIPPING TO 540 MB AS IT MOVES IN. THE
COLDEST AIR ALOFT WILL FILTER IN BEHIND THIS WAVE WITH 900 MB
TEMPERATURES FALLING TO -17C BY FRIDAY AFTERNOON. A RATHER NICE PV
ADVECTION SIGNAL MOVING ACROSS THE FORECAST AREA FRIDAY
MORNING...WITH PV ADVECTION IN THE 500-300 MB LAYER OF AROUND 37
PVU/S. EVEN WITH THIS UPPER LEVEL FORCING...THE LOWER LEVEL ARE
VERY DRY LIMITING OVERALL SNOW CHANCES AS THE WAVE MOVES
THROUGH...WITH LITTLE OR NO CONTRIBUTION FROM FORCING ALOFT.
HOWEVER...GIVEN THE COLD AIR AT 900 MB PRODUCING STEEP LAPSE
RATES...CANNOT RULE OUT A FEW CONVECTIVE SNOW SHOWERS. HAVE
LOWERED PRECIPITATION CHANCES SLIGHTLY. WILL MAINTAIN A SLIGHT
CHANCE OF SNOW SHOWERS THROUGH THE DAY ON FRIDAY EAST OF THE
MISSISSIPPI RIVER. OCCASIONAL FLURRIES CAN BE EXPECTED ACROSS THE
ENTIRE FORECAST AREA. LOOK FOR HIGH TEMPERATURES TO RANGE FROM THE
TEENS ACROSS NORTHERN WISCONSIN TO AROUND 20 ACROSS FAR SOUTHWEST
WISCONSIN. COLD SURFACE HIGH PRESSURE IS EXPECTED TO BUILD INTO
THE FORECAST AREA FRIDAY NIGHT...WITH THE CENTER OF THE HIGH
POSITIONED OVER THE DAKOTAS. LOOK FOR CLOUDS TO GRADUALLY DECREASE
FROM NORTH TO SOUTH LATE FRIDAY NIGHT INTO EARLY SATURDAY MORNING
AS DRIER LOW LEVEL AIR ADVECTS IN AND ERODES ANY LINGERING
STRATUS. LOW TEMPERATURES FRIDAY NIGHT WILL BE ON THE CHILLY
SIDE...WITH LOWS RANGING FROM THE SINGLE DIGITS BELOW ZERO ACROSS
NORTH CENTRAL WISCONSIN TO THE SINGLE DIGITS ABOVE ZERO ACROSS
NORTHEAST IOWA.
LOW PRESSURE WILL DROP SOUTH ACROSS JAMES BAY INTO CENTRAL QUEBEC ON
SATURDAY. MEANWHILE...COLD HIGH PRESSURE IS EXPECTED TO BE CENTERED
OVER THE DAKOTAS. THIS WILL PRODUCE A TIGHT PRESSURE GRADIENT ACROSS
THE UPPER MISSISSIPPI RIVER VALLEY WITH WEST WINDS INCREASING INTO
THE 10 TO 18 MPH RANGE. HIGHS ON SATURDAY WILL BE MAINLY IN THE
TEENS TO AROUND 20 ACROSS NORTHEAST IOWA INTO FAR SOUTHERN
WISCONSIN. PLAN ON WIND CHILLS IN THE SINGLE DIGITS ABOVE TO
SINGLE DIGITS BELOW ZERO ON SATURDAY. LOOK FOR ONE MORE CHILLY
NIGHT SATURDAY NIGHT WITH LOWS DROPPING INTO SINGLE DIGITS. WEST
WINDS WILL GRADUALLY DIMINISH SATURDAY NIGHT AS THE RIDGE AXIS
MOVES INTO THE UPPER MISSISSIPPI RIVER VALLEY.
.LONG TERM...SUNDAY THROUGH WEDNESDAY
250 AM CST THU FEB 9 2012
09.00 MEDIUM RANGE MODELS IN AGREEMENT ON SUNDAY SHOWING AN UPPER
RIDGE ACROSS THE FORECAST AREA WITH A TROUGH DIVING INTO THE
SOUTHWEST CONUS. WARMER TEMPERATURES ARE ON TAP FOR SUNDAY AS 850
MB TEMPS WARM TO AROUND -4 C BY SUNDAY AFTERNOON. PLAN ON MOSTLY
SUNNY SKIES ON SUNDAY WITH HIGH TEMPERATURES IN THE 20S. THE TROUGH
WILL EJECT INTO THE CENTRAL/NORTHERN PLAINS LATE SUNDAY NIGHT AND
MOVE INTO THE UPPER MISSISSIPPI RIVER VALLEY ON MONDAY. THIS SYSTEM
IS EXPECTED TO BRING LIGHT SNOW TO THE FORECAST AREA...WITH LIGHT
ACCUMULATIONS POSSIBLE. LATEST GUIDANCE SUGGEST 1 TO 3 INCHES OF
ACCUMULATION. WILL HAVE TO KEEP A CLOSE WATCH ON THE NEXT FEW MODEL
RUNS. IF TRENDS CONTINUE...SNOW CHANCES WILL LIKELY BE INCREASED
SIGNIFICANTLY. GOOD MODEL AGREEMENT TUESDAY INTO WEDNESDAY SHOWING
ZONAL FLOW ACROSS THE UPPER MISSISSIPPI RIVER VALLEY. MODELS MUCH
DRIER THIS RUN ACROSS THE FORECAST AREA TUESDAY INTO
WEDNESDAY...WITH QUIET ZONAL FLOW ACROSS THE REGION. HAVE DECIDED
TO REMOVE PRECIPITATION CHANCES THROUGH THIS PERIOD. LOOK FOR HIGH
TEMPERATURES IN THE LOW TO MID 30S TUESDAY INTO WEDNESDAY...WITH
OVERNIGHT LOWS IN THE 20S.
&&
.AVIATION...THROUGH 18Z FRIDAY
1127 AM CST THU FEB 9 2012
A LARGE AREA OF STRATUS WAS LOCATED OVER SOUTHERN IOWA AT
17Z...WITH THE NORTHERN EXTENT EXTENDING INTO NORTHEAST IOWA AND
FAR SOUTHEAST MINNESOTA. MEANWHILE...A COLD FRONT WAS STRETCHED
FROM JUST NORTH OF LAKE SUPERIOR...INTO NORTHERN MINNESOTA. 09.14Z
HRRR ALONG WITH THE 09.15Z RUC DOES SHOW THE STRATUS OVER
NORTHEAST IOWA TO SKIRT ALONG THE TAF SITES THIS AFTERNOON. DID
MENTION A SCATTERED DECK AT BOTH SITES...BUT FEEL CEILINGS WILL BE
SOUTH OF THE AREA. IF CEILINGS DO DEVELOP THEY WILL BE SHORT
LIVED...ESPECIALLY AT KRST. ANY CEILINGS THAT DO DEVELOP WOULD BE IN THE
MVFR CATEGORY. NEXT CONCERN IS ON ARCTIC BOUNDARY THAT WILL PUSH
ACROSS THE TAF SITES LATER TONIGHT. WINDS WILL SWITCH AROUND TO A
WEST THEN NORTHWEST DIRECTION BETWEEN 06Z-09Z WITH SPEEDS
INCREASING AND SOME GUSTS TO 20 TO 23 KNOTS. MVFR STRATUS IS
EXPECTED BEHIND THE FRONT WHICH WILL CONTINUE THROUGH 18Z FRIDAY.
COULD ALSO BE SOME -SHSN...BUT DID NOT BRING ANY RESTRICTIONS TO
VISIBILITY WITHIN THE -SHSN.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
250 AM CST THU FEB 9 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...WETENKAMP
LONG TERM....WETENKAMP
AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
520 AM CST THU FEB 9 2012
.SHORT TERM...TODAY THROUGH SATURDAY NIGHT
250 AM CST THU FEB 9 2012
MAIN FORECAST CONCERNS ARE ON LIGHT SNOW/FLURRY CHANCES TONIGHT
THROUGH FRIDAY AND HIGH TEMPERATURES FRIDAY INTO SATURDAY BEHIND
THE ARCTIC COLD FRONT.
CURRENT SURFACE OBSERVATIONS SHOWED A COLD FRONT EXTENDING FROM
CENTRAL ONTARIO WEST THROUGH SOUTHERN MANITOBA INTO SOUTHERN
SASKATCHEWAN. THE FRONT WAS MOVING SOUTH EARLY THIS MORNING. AN
AREA OF STRATUS WAS NOTED ACROSS EASTERN NEBRASKA/SOUTHWEST
IOWA...MOVING EAST AND SLIGHTLY NORTHEAST. WILL HAVE TO KEEP A
CLOSE WATCH ON THIS AREA OF STRATUS AS SOUTHWEST WINDS INCREASE
AHEAD OF THE FRONT THIS MORNING INTO THIS AFTERNOON WITH THE
POSSIBILITY OF THE STRATUS ADVECTING INTO THE FORECAST AREA.
HIGH PRESSURE WILL SLIDE SOUTH OF THE REGION TODAY AS THE ARCTIC
COLD FRONT APPROACHES THE REGION. THE HRRR DEVELOPS AN AREA OF
STRATUS ACROSS SOUTHWEST/SOUTH CENTRAL MINNESOTA INTO NORTHEAST IOWA
LATE THIS MORNING...WITH THE STRATUS SPREADING EAST OF THE
MISSISSIPPI RIVER THIS AFTERNOON. FORECAST SOUNDINGS ACROSS
SOUTH CENTRAL MINNESOTA AND NORTHEAST IOWA SHOW VERY DRY AIR IN
THE LOWER LEVELS OF THE ATMOSPHERE LATE THIS MORNING INTO THIS
AFTERNOON. SURFACE DEWPOINTS ACROSS THIS AREA ARE ONLY IN THE
SINGLE DIGITS TO LOWER TEENS WITH THE ONLY APPRECIABLE LOW LEVEL
MOISTURE NOTED IN THE AREA OF STRATUS ACROSS EASTERN NEBRASKA INTO
SOUTHWEST IOWA. PLAN ON MOSTLY SUNNY SKIES THROUGH EARLY AFTERNOON
WITH CLOUDS INCREASING DURING THE LATE AFTERNOON AND EARLY EVENING
HOURS AS THE COLD FRONT MOVES INTO THE FORECAST AREA. THE FRONT IS
EXPECTED TO BE POSITIONED FROM WESTERN LAKE SUPERIOR INTO
SOUTHWEST MINNESOTA BY 6 PM THIS EVENING. LOOK FOR THE FRONT TO
SWEEP ACROSS THE AREA DURING THE EVENING HOURS. THE BEST FORCING
FOR PRECIPITATION APPEARS TO BE RIGHT ALONG AND SLIGHTLY TRAILING
THE COLD FRONT. WOULD EXPECT TO SEE A FEW FLURRIES OR LIGHT SNOW
SHOWERS THIS EVENING INTO THE OVERNIGHT HOURS AS THE FRONT MOVES
THROUGH. NAM FORECAST SOUNDINGS SHOW THE POTENTIAL FOR SNOW
SHOWERS...MAINLY EAST OF THE MISSISSIPPI RIVER TONIGHT. THE GFS
SHOWS A BRIEF WINDOW OF FLURRIES/LIGHT SNOW SHOWERS THIS EVENING
BEFORE DRY/COLD AIR MOVES IN. A BRIEF SHOT OF ISENTROPIC LIFT
NOTED IN THE LATEST NAM SOLUTION ON THE 270 THROUGH 280 K SURFACES
THIS EVENING WITH CONDENSATION PRESSURE DEFICITS LOWERING TO
AROUND 7 MB WITHIN THIS LAYER. IF LIGHT SNOW DEVELOPS...LITTLE OR
NO ACCUMULATION IS EXPECTED WITH THIS ACTIVITY. WILL INCLUDE A
SLIGHT CHANCE OF VERY LIGHT SNOW ACROSS SOUTHEAST
MINNESOTA...NORTHEAST IOWA INTO SOUTHWEST AND CENTRAL WISCONSIN.
SLIGHTLY HIGHER CHANCES FOR SNOW ACROSS NORTH CENTRAL WISCONSIN.
OTHERWISE...PLAN ON MOSTLY CLOUDY SKIES OVERNIGHT WITH LOW
TEMPERATURES RANGING FROM THE SINGLE DIGITS BELOW ZERO ACROSS
NORTH CENTRAL WISCONSIN TO THE UPPER TEENS ACROSS PORTIONS OF
NORTHEAST IOWA INTO FAR SOUTHWEST WISCONSIN.
AN UPPER LEVEL TROUGH IS EXPECTED TO PUSH INTO THE AREA ON
FRIDAY...WITH PV15 SURFACES DIPPING TO 540 MB AS IT MOVES IN. THE
COLDEST AIR ALOFT WILL FILTER IN BEHIND THIS WAVE WITH 900 MB
TEMPERATURES FALLING TO -17C BY FRIDAY AFTERNOON. A RATHER NICE PV
ADVECTION SIGNAL MOVING ACROSS THE FORECAST AREA FRIDAY
MORNING...WITH PV ADVECTION IN THE 500-300 MB LAYER OF AROUND 37
PVU/S. EVEN WITH THIS UPPER LEVEL FORCING...THE LOWER LEVEL ARE
VERY DRY LIMITING OVERALL SNOW CHANCES AS THE WAVE MOVES
THROUGH...WITH LITTLE OR NO CONTRIBUTION FROM FORCING ALOFT.
HOWEVER...GIVEN THE COLD AIR AT 900 MB PRODUCING STEEP LAPSE
RATES...CANNOT RULE OUT A FEW CONVECTIVE SNOW SHOWERS. HAVE
LOWERED PRECIPITATION CHANCES SLIGHTLY. WILL MAINTAIN A SLIGHT
CHANCE OF SNOW SHOWERS THROUGH THE DAY ON FRIDAY EAST OF THE
MISSISSIPPI RIVER. OCCASIONAL FLURRIES CAN BE EXPECTED ACROSS THE
ENTIRE FORECAST AREA. LOOK FOR HIGH TEMPERATURES TO RANGE FROM THE
TEENS ACROSS NORTHERN WISCONSIN TO AROUND 20 ACROSS FAR SOUTHWEST
WISCONSIN. COLD SURFACE HIGH PRESSURE IS EXPECTED TO BUILD INTO
THE FORECAST AREA FRIDAY NIGHT...WITH THE CENTER OF THE HIGH
POSITIONED OVER THE DAKOTAS. LOOK FOR CLOUDS TO GRADUALLY DECREASE
FROM NORTH TO SOUTH LATE FRIDAY NIGHT INTO EARLY SATURDAY MORNING
AS DRIER LOW LEVEL AIR ADVECTS IN AND ERODES ANY LINGERING
STRATUS. LOW TEMPERATURES FRIDAY NIGHT WILL BE ON THE CHILLY
SIDE...WITH LOWS RANGING FROM THE SINGLE DIGITS BELOW ZERO ACROSS
NORTH CENTRAL WISCONSIN TO THE SINGLE DIGITS ABOVE ZERO ACROSS
NORTHEAST IOWA.
LOW PRESSURE WILL DROP SOUTH ACROSS JAMES BAY INTO CENTRAL QUEBEC ON
SATURDAY. MEANWHILE...COLD HIGH PRESSURE IS EXPECTED TO BE CENTERED
OVER THE DAKOTAS. THIS WILL PRODUCE A TIGHT PRESSURE GRADIENT ACROSS
THE UPPER MISSISSIPPI RIVER VALLEY WITH WEST WINDS INCREASING INTO
THE 10 TO 18 MPH RANGE. HIGHS ON SATURDAY WILL BE MAINLY IN THE
TEENS TO AROUND 20 ACROSS NORTHEAST IOWA INTO FAR SOUTHERN
WISCONSIN. PLAN ON WIND CHILLS IN THE SINGLE DIGITS ABOVE TO
SINGLE DIGITS BELOW ZERO ON SATURDAY. LOOK FOR ONE MORE CHILLY
NIGHT SATURDAY NIGHT WITH LOWS DROPPING INTO SINGLE DIGITS. WEST
WINDS WILL GRADUALLY DIMINISH SATURDAY NIGHT AS THE RIDGE AXIS
MOVES INTO THE UPPER MISSISSIPPI RIVER VALLEY.
.LONG TERM...SUNDAY THROUGH WEDNESDAY
250 AM CST THU FEB 9 2012
09.00 MEDIUM RANGE MODELS IN AGREEMENT ON SUNDAY SHOWING AN UPPER
RIDGE ACROSS THE FORECAST AREA WITH A TROUGH DIVING INTO THE
SOUTHWEST CONUS. WARMER TEMPERATURES ARE ON TAP FOR SUNDAY AS 850
MB TEMPS WARM TO AROUND -4 C BY SUNDAY AFTERNOON. PLAN ON MOSTLY
SUNNY SKIES ON SUNDAY WITH HIGH TEMPERATURES IN THE 20S. THE TROUGH
WILL EJECT INTO THE CENTRAL/NORTHERN PLAINS LATE SUNDAY NIGHT AND
MOVE INTO THE UPPER MISSISSIPPI RIVER VALLEY ON MONDAY. THIS SYSTEM
IS EXPECTED TO BRING LIGHT SNOW TO THE FORECAST AREA...WITH LIGHT
ACCUMULATIONS POSSIBLE. LATEST GUIDANCE SUGGEST 1 TO 3 INCHES OF
ACCUMULATION. WILL HAVE TO KEEP A CLOSE WATCH ON THE NEXT FEW MODEL
RUNS. IF TRENDS CONTINUE...SNOW CHANCES WILL LIKELY BE INCREASED
SIGNIFICANTLY. GOOD MODEL AGREEMENT TUESDAY INTO WEDNESDAY SHOWING
ZONAL FLOW ACROSS THE UPPER MISSISSIPPI RIVER VALLEY. MODELS MUCH
DRIER THIS RUN ACROSS THE FORECAST AREA TUESDAY INTO
WEDNESDAY...WITH QUIET ZONAL FLOW ACROSS THE REGION. HAVE DECIDED
TO REMOVE PRECIPITATION CHANCES THROUGH THIS PERIOD. LOOK FOR HIGH
TEMPERATURES IN THE LOW TO MID 30S TUESDAY INTO WEDNESDAY...WITH
OVERNIGHT LOWS IN THE 20S.
&&
.AVIATION...TODAY AND TONIGHT
520 AM CST THU FEB 9 2012
THE MAIN FOCUS WITH THE TAFS IS ON THE COLD FRONT THAT COMES
THROUGH TONIGHT AND WHETHER THE CEILINGS WILL DROP TO MVFR AS IT
PASSES. THIS FRONT CURRENTLY STRETCHES ACROSS SOUTHERN ONTARIO AND
MANITOBA NEAR WINNIPEG AND IS TIMED TO REACH RST AND LSE AROUND
5-6Z TONIGHT. SOME SNOW SHOWERS OR FLURRIES WILL BE POSSIBLE AS
WELL...BUT WAS NOT CONFIDENT ENOUGH TO PUT ANY VISIBILITY
RESTRICTIONS IN THE FORECAST. HOWEVER...CEILINGS DO SEEM TO BE A
GOOD BET TO DROP DOWN WITH SOME MOISTURE GETTING TRAPPED IN THE
LOW LEVELS BEHIND AND ALONG THE FRONT. WINDS WILL ALSO BE AN ISSUE
AHEAD AS WELL AS BEHIND THE FRONT WITH GUSTS GETTING UP INTO THE
20 TO 25KT RANGE ON BOTH ENDS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
250 AM CST THU FEB 9 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...WETENKAMP
LONG TERM....WETENKAMP
AVIATION...HALBACH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
250 AM CST THU FEB 9 2012
.SHORT TERM...TODAY THROUGH SATURDAY NIGHT
250 AM CST THU FEB 9 2012
MAIN FORECAST CONCERNS ARE ON LIGHT SNOW/FLURRY CHANCES TONIGHT
THROUGH FRIDAY AND HIGH TEMPERATURES FRIDAY INTO SATURDAY BEHIND
THE ARCTIC COLD FRONT.
CURRENT SURFACE OBSERVATIONS SHOWED A COLD FRONT EXTENDING FROM
CENTRAL ONTARIO WEST THROUGH SOUTHERN MANITOBA INTO SOUTHERN
SASKATCHEWAN. THE FRONT WAS MOVING SOUTH EARLY THIS MORNING. AN
AREA OF STRATUS WAS NOTED ACROSS EASTERN NEBRASKA/SOUTHWEST
IOWA...MOVING EAST AND SLIGHTLY NORTHEAST. WILL HAVE TO KEEP A
CLOSE WATCH ON THIS AREA OF STRATUS AS SOUTHWEST WINDS INCREASE
AHEAD OF THE FRONT THIS MORNING INTO THIS AFTERNOON WITH THE
POSSIBILITY OF THE STRATUS ADVECTING INTO THE FORECAST AREA.
HIGH PRESSURE WILL SLIDE SOUTH OF THE REGION TODAY AS THE ARCTIC
COLD FRONT APPROACHES THE REGION. THE HRRR DEVELOPS AN AREA OF
STRATUS ACROSS SOUTHWEST/SOUTH CENTRAL MINNESOTA INTO NORTHEAST IOWA
LATE THIS MORNING...WITH THE STRATUS SPREADING EAST OF THE
MISSISSIPPI RIVER THIS AFTERNOON. FORECAST SOUNDINGS ACROSS
SOUTH CENTRAL MINNESOTA AND NORTHEAST IOWA SHOW VERY DRY AIR IN
THE LOWER LEVELS OF THE ATMOSPHERE LATE THIS MORNING INTO THIS
AFTERNOON. SURFACE DEWPOINTS ACROSS THIS AREA ARE ONLY IN THE
SINGLE DIGITS TO LOWER TEENS WITH THE ONLY APPRECIABLE LOW LEVEL
MOISTURE NOTED IN THE AREA OF STRATUS ACROSS EASTERN NEBRASKA INTO
SOUTHWEST IOWA. PLAN ON MOSTLY SUNNY SKIES THROUGH EARLY AFTERNOON
WITH CLOUDS INCREASING DURING THE LATE AFTERNOON AND EARLY EVENING
HOURS AS THE COLD FRONT MOVES INTO THE FORECAST AREA. THE FRONT IS
EXPECTED TO BE POSITIONED FROM WESTERN LAKE SUPERIOR INTO
SOUTHWEST MINNESOTA BY 6 PM THIS EVENING. LOOK FOR THE FRONT TO
SWEEP ACROSS THE AREA DURING THE EVENING HOURS. THE BEST FORCING
FOR PRECIPITATION APPEARS TO BE RIGHT ALONG AND SLIGHTLY TRAILING
THE COLD FRONT. WOULD EXPECT TO SEE A FEW FLURRIES OR LIGHT SNOW
SHOWERS THIS EVENING INTO THE OVERNIGHT HOURS AS THE FRONT MOVES
THROUGH. NAM FORECAST SOUNDINGS SHOW THE POTENTIAL FOR SNOW
SHOWERS...MAINLY EAST OF THE MISSISSIPPI RIVER TONIGHT. THE GFS
SHOWS A BRIEF WINDOW OF FLURRIES/LIGHT SNOW SHOWERS THIS EVENING
BEFORE DRY/COLD AIR MOVES IN. A BRIEF SHOT OF ISENTROPIC LIFT
NOTED IN THE LATEST NAM SOLUTION ON THE 270 THROUGH 280 K SURFACES
THIS EVENING WITH CONDENSATION PRESSURE DEFICITS LOWERING TO
AROUND 7 MB WITHIN THIS LAYER. IF LIGHT SNOW DEVELOPS...LITTLE OR
NO ACCUMULATION IS EXPECTED WITH THIS ACTIVITY. WILL INCLUDE A
SLIGHT CHANCE OF VERY LIGHT SNOW ACROSS SOUTHEAST
MINNESOTA...NORTHEAST IOWA INTO SOUTHWEST AND CENTRAL WISCONSIN.
SLIGHTLY HIGHER CHANCES FOR SNOW ACROSS NORTH CENTRAL WISCONSIN.
OTHERWISE...PLAN ON MOSTLY CLOUDY SKIES OVERNIGHT WITH LOW
TEMPERATURES RANGING FROM THE SINGLE DIGITS BELOW ZERO ACROSS
NORTH CENTRAL WISCONSIN TO THE UPPER TEENS ACROSS PORTIONS OF
NORTHEAST IOWA INTO FAR SOUTHWEST WISCONSIN.
AN UPPER LEVEL TROUGH IS EXPECTED TO PUSH INTO THE AREA ON
FRIDAY...WITH PV15 SURFACES DIPPING TO 540 MB AS IT MOVES IN. THE
COLDEST AIR ALOFT WILL FILTER IN BEHIND THIS WAVE WITH 900 MB
TEMPERATURES FALLING TO -17C BY FRIDAY AFTERNOON. A RATHER NICE PV
ADVECTION SIGNAL MOVING ACROSS THE FORECAST AREA FRIDAY
MORNING...WITH PV ADVECTION IN THE 500-300 MB LAYER OF AROUND 37
PVU/S. EVEN WITH THIS UPPER LEVEL FORCING...THE LOWER LEVEL ARE
VERY DRY LIMITING OVERALL SNOW CHANCES AS THE WAVE MOVES
THROUGH...WITH LITTLE OR NO CONTRIBUTION FROM FORCING ALOFT.
HOWEVER...GIVEN THE COLD AIR AT 900 MB PRODUCING STEEP LAPSE
RATES...CANNOT RULE OUT A FEW CONVECTIVE SNOW SHOWERS. HAVE
LOWERED PRECIPITATION CHANCES SLIGHTLY. WILL MAINTAIN A SLIGHT
CHANCE OF SNOW SHOWERS THROUGH THE DAY ON FRIDAY EAST OF THE
MISSISSIPPI RIVER. OCCASIONAL FLURRIES CAN BE EXPECTED ACROSS THE
ENTIRE FORECAST AREA. LOOK FOR HIGH TEMPERATURES TO RANGE FROM THE
TEENS ACROSS NORTHERN WISCONSIN TO AROUND 20 ACROSS FAR SOUTHWEST
WISCONSIN. COLD SURFACE HIGH PRESSURE IS EXPECTED TO BUILD INTO
THE FORECAST AREA FRIDAY NIGHT...WITH THE CENTER OF THE HIGH
POSITIONED OVER THE DAKOTAS. LOOK FOR CLOUDS TO GRADUALLY DECREASE
FROM NORTH TO SOUTH LATE FRIDAY NIGHT INTO EARLY SATURDAY MORNING
AS DRIER LOW LEVEL AIR ADVECTS IN AND ERODES ANY LINGERING
STRATUS. LOW TEMPERATURES FRIDAY NIGHT WILL BE ON THE CHILLY
SIDE...WITH LOWS RANGING FROM THE SINGLE DIGITS BELOW ZERO ACROSS
NORTH CENTRAL WISCONSIN TO THE SINGLE DIGITS ABOVE ZERO ACROSS
NORTHEAST IOWA.
LOW PRESSURE WILL DROP SOUTH ACROSS JAMES BAY INTO CENTRAL QUEBEC ON
SATURDAY. MEANWHILE...COLD HIGH PRESSURE IS EXPECTED TO BE CENTERED
OVER THE DAKOTAS. THIS WILL PRODUCE A TIGHT PRESSURE GRADIENT ACROSS
THE UPPER MISSISSIPPI RIVER VALLEY WITH WEST WINDS INCREASING INTO
THE 10 TO 18 MPH RANGE. HIGHS ON SATURDAY WILL BE MAINLY IN THE
TEENS TO AROUND 20 ACROSS NORTHEAST IOWA INTO FAR SOUTHERN
WISCONSIN. PLAN ON WIND CHILLS IN THE SINGLE DIGITS ABOVE TO
SINGLE DIGITS BELOW ZERO ON SATURDAY. LOOK FOR ONE MORE CHILLY
NIGHT SATURDAY NIGHT WITH LOWS DROPPING INTO SINGLE DIGITS. WEST
WINDS WILL GRADUALLY DIMINISH SATURDAY NIGHT AS THE RIDGE AXIS
MOVES INTO THE UPPER MISSISSIPPI RIVER VALLEY.
.LONG TERM...SUNDAY THROUGH WEDNESDAY
250 AM CST THU FEB 9 2012
09.00 MEDIUM RANGE MODELS IN AGREEMENT ON SUNDAY SHOWING AN UPPER
RIDGE ACROSS THE FORECAST AREA WITH A TROUGH DIVING INTO THE
SOUTHWEST CONUS. WARMER TEMPERATURES ARE ON TAP FOR SUNDAY AS 850
MB TEMPS WARM TO AROUND -4 C BY SUNDAY AFTERNOON. PLAN ON MOSTLY
SUNNY SKIES ON SUNDAY WITH HIGH TEMPERATURES IN THE 20S. THE TROUGH
WILL EJECT INTO THE CENTRAL/NORTHERN PLAINS LATE SUNDAY NIGHT AND
MOVE INTO THE UPPER MISSISSIPPI RIVER VALLEY ON MONDAY. THIS SYSTEM
IS EXPECTED TO BRING LIGHT SNOW TO THE FORECAST AREA...WITH LIGHT
ACCUMULATIONS POSSIBLE. LATEST GUIDANCE SUGGEST 1 TO 3 INCHES OF
ACCUMULATION. WILL HAVE TO KEEP A CLOSE WATCH ON THE NEXT FEW MODEL
RUNS. IF TRENDS CONTINUE...SNOW CHANCES WILL LIKELY BE INCREASED
SIGNIFICANTLY. GOOD MODEL AGREEMENT TUESDAY INTO WEDNESDAY SHOWING
ZONAL FLOW ACROSS THE UPPER MISSISSIPPI RIVER VALLEY. MODELS MUCH
DRIER THIS RUN ACROSS THE FORECAST AREA TUESDAY INTO
WEDNESDAY...WITH QUIET ZONAL FLOW ACROSS THE REGION. HAVE DECIDED
TO REMOVE PRECIPITATION CHANCES THROUGH THIS PERIOD. LOOK FOR HIGH
TEMPERATURES IN THE LOW TO MID 30S TUESDAY INTO WEDNESDAY...WITH
OVERNIGHT LOWS IN THE 20S.
&&
.AVIATION...
1025 PM CST WED FEB 8 2012
HIGH PRESSURE SETTLING TO THE SOUTH ACROSS IOWA/MISSOURI WILL ALLOW
SURFACE WINDS AT BOTH TAF SITES TO TURN TO THE SOUTHWEST. DURING THE
DAYTIME...A TIGHTENING PRESSURE GRADIENT AHEAD OF AN APPROACHING
ARCTIC COLD FRONT WILL PROMOTE GUSTY WINDS...PARTICULARLY AT KRST.
ONE THING TO NOTE...CURRENTLY WATCHING AREA OF MVFR STRATUS ACROSS
EASTERN NEBRASKA / WESTERN IOWA. RECENT FORECAST GUIDANCE TRIES TO
SWING THIS TOWARDS NORTHERN IOWA / SOUTHERN MINNESOTA BY THURSDAY
MORNING. CONFIDENCE IS LOW ON THIS SCENARIO AT THIS TIME GIVEN DRIER
AIR AND THINKING DAYTIME MIXING WILL HELP TO ERODE THESE CLOUDS.
HOWEVER...SOMETHING TO WATCH CLOSELY THROUGH THE OVERNIGHT.
TOWARDS THE END OF THE FORECAST PERIOD...THE ARCTIC FRONT SHOULD BE
NEARING OR CROSSING BOTH TAF SITES...BRINGING NORTHERLY WINDS AND
MOSTLY MID TO HIGH LEVEL CLOUDS. SEE THE POTENTIAL FOR MVFR CIGS
AFTER 06Z HOWEVER...AND THIS MAY NEED TO ADDED TO LATER FORECASTS.
THE BEST FORCING FOR ANY SNOW SHOWERS WILL REMAIN NORTHEAST OF THE
TAF SITES.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
250 AM CST THU FEB 9 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...WETENKAMP
LONG TERM....WETENKAMP
AVIATION.....TAYLOR
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1007 PM MST WED FEB 8 2012
.AVIATION...06Z TAFS
VFR CONDITIONS EXPECTED AT ALL LOCATIONS EXCEPT RAWLINS. THEY ARE
LOOKING AT MVFR CONDITIONS THROUGH THE MORNING HOURS BEFORE CLOUDS
BREAK AFTER 09Z. VFR CONDITIONS AFTERWARDS.
CLAYCOMB
&&
PREV DISCUSSION... /ISSUED 306 PM MST WED FEB 8 2012/
SHORT TERM...
CURRENTLY SOME STRONGER WINDS INTO THE ARLINGTON AREA AS WELL AS
NEAR VEDAUWOO WITH SUSTAINED WINDS AROUND 40 MPH AND GUSTS
GENERALLY AROUND 50 MPH. THESE WINDS ARE LARGELY IN RESPONSE TO
THE SHORTWAVE CURRENTLY MOVING ACROSS THE BLACK HILLS OF SOUTH
DAKOTA. AS THE WAVE CONTINUES SOUTHEAST THIS AFTERNOON THE GRADIENT
WILL RELAX AND WIND WILL DECREASE. 2 KM WINDS OFF THE THE MEDICINE
BOW PROFILER MAY ALREADY BE SHOWING THIS AS MAGNITUDE DROPPED FROM
40 KTS TO 35 KTS. ALTHOUGH THE GRADIENT WILL DECREASE...MODELS
INDICATE A STABLE LAYER BEING PUSHED TO THE SURFACE THIS EVENING
AS SUBSIDENCE KICKS IN BEHIND THE SHORTWAVE. COULD SEE SOME GUSTY
WINDS LATER THIS EVENING INTO LATER TONIGHT FOR AREAS LEE OF THE
LARAMIE RANGE...MAINLY FROM INTERSTATE 25 WEST. NOT LOOKING AT
ANYTHING TOO STRONG...BUT 20 TO 25 MPH WITH GUSTS 30 TO 35 MPH
SEEM LIKE A GOOD BET.
FOG OVER THE NEBRASKA PANHANDLE THIS MORNING HAS LIFTED AND PUSHED
WELL TO THE EAST DUE TO MIXING AND LIGHT WESTERLY FLOW. NOT OVERLY
CONCERNED THAT FOG WILL REFORM TONIGHT ALTHOUGH NOT ABLE TO RULE
IT OUT COMPLETELY FROM ROUGHLY EAST OF A LINE FROM CHADRON TO
SYDNEY. GUIDANCE AND HRRR INDICATE FOG COULD FORM LATE TONIGHT IN
THIS AREA. THINKING IS LIGHT WESTERLY FLOW WILL KEEP WIDESPREAD
DENSE FOG AT BAY BUT DID ADD PATCHY FOG INTO THE WESTERN TIER OF
COUNTIES.
PRECIPITATION CHANCES TONIGHT WILL BE CONFINED TO AREAS WEST OF THE
LARAMIE RANGE...MAINLY OVER THE SNOWY AND SIERRIA MADRES. RADAR
INDICATING SOME PRECIPITATION ALREADY REACHING IN THE GROUND IN
THESE AREAS AND OLD BATTLE SNOWTEL SHOWED SOME LIGHT ACCUMULATION
THIS AFTERNOON. MAIN SURGE OF UPSLOPE MOISTURE WILL BE THIS
EVENING WHEN SEVERAL INCHES OF SNOW ARE LIKELY IN HIGHER
ELEVATION. SNOW WILL MOSTLY TAPER OFF BY LATE TONIGHT.
THURSDAY WILL BE A DRY WITH A WEAK RIDGE SHIFTING INTO THE AREA
BUT CHANCES FOR PRECIPITATION WILL INCREASE THURSDAY NIGHT INTO
FRIDAY AS AN UPPER TROUGH DIVES INTO THE NORTHERN PLAINS AND
ASSOCIATED ARCTIC FRONT BACKS INTO THE HIGH PLAINS. MODELS
STRUGGLING TO REACH CONSENSUS AS TO HOW FAR WEST THE FRONT WILL
MAKE IT AND TO THE PLACEMENT AND EXTENT OF SNOW. GFS HAS BEEN
CONSISTENTLY FARTHER EAST WITH THIS SYSTEM...KEEPING THE BULK OF
THE SNOW AND COLD AIR ACROSS WESTERN NEBRASKA. GEM...NAM...AND EC
ALL FARTHER WEST WITH THE EC BEING THE MOST BULLISH ON QPF
AMOUNTS. INCREASED POPS ACROSS THE CWA BUT CONFIDENCE IN AMOUNTS
AND PLACEMENT ARE CURRENTLY LOW. WILL WAIT TO SEE WHAT THE
UPCOMING MODELS BRING BUT IT SHOULD BE NOTED THAT WERE THE EC TO
VERIFY...SOME LOCATIONS ALONG AND LEE OF THE LARAMIE RANGE...COULD
PICK UP OVER 6 INCHES OF SNOW...INCLUDING CHEYENNE.
LONG TERM...
SATURDAY WILL BE UNSEASONABLY COOL ACROSS THE CWA WITH STRATUS TO
THE EAST OF THE LARAMIE RANGE. A 1040MB SFC HIGH ACROSS THE PLAINS
WILL CAUSE SOUTHEASTERLY SFC UPSLOPE. BUMPED UP POPS INTO THE
SLIGHT CHANCE CATEGORY FOR AREAS EAST OF THE LARAMIE RANGE...HOWEVER
ANY SNOW AMOUNTS WILL BE VERY LIGHT. A SHORTWAVE RIDGE PROGRESSES OVER
THE AREA ON SAT NIGHT IN ADVANCE OF A LOW PRESSURE SYSTEM PROGGED TO
TRACK SOUTH OF THE CWA ON SUNDAY. THE STRONGEST DYNAMICS WILL BE
WELL SOUTH OF SOUTHEAST WY IN NEW MEXICO AND SOUTHERN CO. IN
ADDITION...WITH A SFC TROUGH FCSTED TO DEVELOP OVER WESTERN NEBRASKA
AND THE ASSOCIATED LACK OF UPSLOPE ON THE PLAINS...THIS SYSTEM WILL
BE PRIMARILY DRY FOR THE CWA. HOWEVER...CAN NOT RULE OUT A FEW SNOW
SHOWERS ACROSS THE SIERRA MADRE/SNOWY RANGE WITH MOISTENING 700MB
WESTERLY FLOW. THE GFS AND ECMWF AGREE ON DIGGING ANOTHER SYSTEM
INTO THE INTERMOUNTAIN WEST ON MONDAY. THE GFS SHOWS THE 700MB LOW
AND SFC LOW TRACKING ACROSS SOUTHERN CO ON TUESDAY...WITH LOW-LEVEL
NORTH AND NORTHEAST WINDS DEVELOPING ACROSS THE PLAINS. LOOKS LIKE
A BETTER SHOT AT PRECIP ON TUESDAY NIGHT/WEDNESDAY TO THE EAST OF
THE LARAMIE RANGE THAN WITH THE SUNDAY SYSTEM. THE ECMWF IS ABOUT
12 HOURS SLOWER WITH THE UPPER TROUGH AND ASSOCIATED PRECIP
DEVELOPMENT. WILL CONTINUE TO MONITOR THE EVOLUTION OF THE
TUESDAY/WEDNESDAY SYSTEM DUE TO ITS POTENTIAL TO PRODUCE MODERATE
SNOW ACCUMULATIONS.
FIRE WEATHER...
NO FIRE WEATHER CONCERNS THE NEXT SEVERAL DAYS. A BIT BREEZY
THURSDAY FOR FAR SOUTHEAST WYOMING AND THE NEBRASKA PANHANDEL BUT
MIN RH WILL MAINLY BE ABOVE 35 PERCENT. CHANCE FOR SNOW ACROSS
MOST OF THE AREA FRIDAY WITH COLD AIR FILTERING INTO THE AREA
FRIDAY NIGHT. COOL AND UNSETTELED WEATHER INTO EARLY NEXT WEEK.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM/FIRE WEATHER...LIEBL
LONG TERM/AVIATION...FINCH
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1150 PM CST FRI FEB 10 2012
.DISCUSSION...
1150 PM CST
HAVE UPGRADED PORTER COUNTY TO A BLIZZARD WARNING FOR THE
REMAINDER OF THE OVERNIGHT HOURS. AFTER MAKING NUMEROUS CALLS TO
LAW ENFORCEMENT AND PUBLIC ACROSS NORTHERN PORTER COUNTY REALIZED
THAT CONDITIONS WERE EVEN MORE SEVERE THAN PREVIOUSLY THOUGHT.
VISBILITIES HAVE BEEN REPORTED TO BE LESS THAN ONE CAR LENGTH AND
ONE PERSON WAS QUOTED AS SAYING THIS STORM MAKES LAST YEARS
BLIZZARD SEEM LIKE NOTHING. COMBINATION OF EXCELLATION OF WINDS
WITHIN THE CONVERGENCE BAND AND CONVECTIVELY MIXING DOWN WIND
GUSTS AM CONFIDENT THAT THE WIND SPEED AND VISIBILITY CRITERIA FOR
A BLIZZARD WILL BE MET. REPORTS OF 8-10 INCHES HAVING FALLEN SO
FAR WITH SEVERAL MORE HOURS OF INTENSE SNOW WITH RATES OF 2-4
INCHES PER HOUR EXPECTED. STORM TOTALS OF A FOOT AND A HALF STILL
LOOK LIKE A DISTINCT POSSIBILITY.
IN ADDITION...BURNS HARBOR JUST CAME IN WITH A 52 KT GUST AT 0521Z
UNDERNEATH THE INTENSE LES BAND. STILL THINK THERE IS A POSSIBILITY
OF ISOLATED THUNDERSTORMS OVERNIGHT WITHIN THE BAND AS WELL GIVEN
THE EXTREME LAKE INDUCED INSTABILITY.
IZZI
&&
.PREV DISCUSSION...
1008 PM CST
REMAINING ADVISORIES HAVE BEEN ALLOWED TO EXPIRE THIS
EVENING...HAVE CONTINUED LAKE EFFECT WARNING FOR LAKE AND PORTER
IN INDIANA...AND HAVE UPGRADED JASPER COUNTY TO A LAKE EFFECT
WARNING.
LATEST RADAR ANALYSIS CONTINUES TO SHOW LAKE EFFECT SNOW SHOWERS
DEVELOPING BUT PRIMARILY REMAINING IN INDIANA...WITH THE MORE
SYNOPTICALLY DRIVEN SNOW HAVING SINCE DIMINISHED OVER THE LAST
COUPLE OF THE HOURS. LATEST TRENDS IN LINE WITH CURRENT HEADLINES
IN PLACE WITH LAKE EFFECT SNOW SHOWERS CONTINUING OVERNIGHT. OVER
THE LAST COUPLE OF HOURS...A STRONGER AND MORE DEFINED SNOW BAND
HAS DEVELOPED AND SITUATED ITSELF OVER LAKE AND PORTER COUNTIES IN
INDIANA. LATEST RUC ANALYSIS SHOWING CONDITIONS OVER THE LAKE HAVE
IMPROVED SIGNIFICANTLY IN REGARDS TO SNOW POTENTIAL WITH 850 DELTA
TS IN UPWARDS OF 18C AND STRONG CONVERGENCE SETTING UP ACROSS THE
LAKE...AS ALSO INDICATED BY LATEST SURFACE/MARINE OBS. LATEST
GUIDANCE IN GOOD AGREEMENT WITH CONDITIONS OVER THE LAKE TO
CONTINUE IMPROVING OVER THE NEXT SEVERAL HOURS. THIS COINCIDING
WITH A LONG FETCH OVER THE LAKE AND DECENT INVERSION
HEIGHTS...SHOULD ALLOW FOR CONTINUED DEVELOPMENT INTO THE EARLY
MORNING HOURS ON SATURDAY. SHORT RANGE GUIDANCE IS INDICATING THAT
THIS BAND WILL REMAIN SITUATED OVER THE LAKE/PORTER COUNTY LINE
BEFORE LOW LEVEL/BOUNDARY LAYER FLOW SHIFTS MORE EAST AND HELPS
STEER IT MORE OVER PORTER COUNTY BY THE EARLY MORNING HOURS. HAVE
INCREASE SNOW AMOUNTS ACROSS JASPER COUNTY AS LATEST RADAR RETURNS
HAVE BEEN REACHING THE NORTHERN PORTIONS OF THE COUNTY. WITH
CONDITIONS EXPECTED TO ONLY BECOME MORE FAVORABLE TONIGHT AND WITH
STRONG FLOW IN PLACE...PORTIONS OF JASPER COUNTY SHOULD SEE
WARNING CRITERIA SNOW. FORECASTED SNOW AMOUNTS CONTINUE TO BE IN
LINE WITH THE HIGHEST AMOUNTS STILL EXPECTED WITHIN PORTER
COUNTY...BEFORE THIS BAND SHIFTS EAST WITH TIME SATURDAY MORNING.
RODRIGUEZ
//PREV DISCUSSION...
355 PM CST
THE ONGOING SNOW EVENT WILL TRANSITION TO MORE OF A TRUE LAKE
EFFECT SNOW STORM INTO MAINLY NORTHWEST INDIANA THIS EVENING. THE
COMBINATION OF THE SNOW...GUSTY WINDS...AND FALLING TEMPERATURES
FREEZING SOME OF THE EARLIER MELTED SNOWFALL WILL CONTINUE TO
CREATE IMPACTS FOR A LARGE PART OF THE AREA INTO EARLY
EVENING...AND NORTHWEST INDIANA ALL NIGHT LONG.
LATE THIS AFTERNOON THROUGH SATURDAY
THE ARCTIC FRONT WILL CONTINUE TO MOVE SOUTHWARD...CLEARING THE
AREA BY EARLY EVENING. NORTHERLY WINDS GUSTING UP TO 35 MPH HAVE
USHERED IN A MUCH COLDER AIR ACROSS THE AREA WITH WIND CHILLS
HAVING DROPPED TO NEAR ZERO ALREADY ALONG THE WI STATE LINE. WATER
VAPOR SATELLITE SHOWS THE MAIN UPPER LEVEL WAVE MOVING OVER THE
AREA...WHICH COMBINED WITH THE STEEP LOW-LEVEL LAPSE RATES WILL
CONTINUE GENERAL SNOWFALL ACROSS THE IL AREA THROUGH EARLY TO MID
EVENING. SOME LAKE ENHANCEMENT IMMEDIATELY NEAR THE LAKE MICHIGAN
SHORE IS LIKELY.
A TRUE LAKE EFFECT BAND HAS ALREADY DEVELOPED JUST OFFSHORE BASED
ON KMKX/TORD RADAR SIGNATURES. THIS WILL CONTINUE TO BECOME
BETTER ESTABLISHED INTO COOK AND NORTHWEST LAKE COUNTIES THROUGH
EARLY EVENING BASED ON SHORT TERM GUIDANCE DEPICTION OF LOW-LEVEL
CONVERGENCE AND INSTABILITY. BY 9 PM AND AFTER...THE
EMPHASIS WILL BE SHIFTING INTO FAR SOUTHEAST COOK AND LAKE
COUNTIES WITH HIGH CONFIDENCE IN SHORT TERM MODELS. IT IS POSSIBLE
THE ADVISORY WILL NEED TO BE EXTENDED FOR COOK COUNTY AFTER 9
PM...AS SNOWFALL RATES WITHIN SUCH A BAND ARE LIKELY TO BE HEAVY
WITH EFFICIENT SNOW-TO-LIQUID RATIOS AND THE PRESENT INSTABILITY.
THE STRONG TEMPERATURE DIFFERENCE BETWEEN THE AIR MOVING OVER THE
LAKE AND THE 38 TO 43 DEGREE OPEN WATER LAKE TEMPERATURES ACROSS
THE SOUTHERN HALF WILL HELP TO GENERATE LAKE-INDUCED CAPE VALUES
TO 500 J/KG BY AFTER 9 PM...LASTING THROUGH THE OVERNIGHT AND
SHIFTING SLOWLY EAST. FAR SOUTHEAST COOK COUNTY COULD SEE TOTAL
SNOWFALL AMOUNTS APPROACH SIX INCHES.
THE CONVERGENT AXIS WILL ROTATE EAST FOCUSING INTO LAKE AND PORTER
COUNTIES OVERNIGHT. THE RATIOS SHOULD CONTINUE TO INCREASE...WITH
THE FAVORABLE SNOW GROWTH ZONE LOCATED BELOW THE EQUILIBRIUM
LEVEL. THE HIGHER WIND SPEEDS ARE LIKELY TO BREAK UP THE FLAKES
SOME...BUT THE HEAVY RATES SHOULD STILL COMPENSATE FOR THAT.
SIMULATED REFLECTIVITY ON SHORT TERM GUIDANCE ALSO RAMPS UP DURING
THAT TIME. THE TREND WITH ALMOST ALL HIGH RESOLUTION GUIDANCE WAS
TO SHIFT THIS EAST SLIGHTLY...REALLY FOCUSING INTO PORTER COUNTY
OVERNIGHT. THE HIGHEST SNOWFALL AMOUNTS TOWARD TEN INCHES IN OUR
FORECAST ARE FOCUSED IN EASTERN LAKE AND PORTER COUNTIES. THE
WIDTH OF THE BAND LOOKS TO NARROW AS IT SHIFTS EAST THOUGH...SO
AGAIN SOME UNCERTAINTY CONTINUES DUE TO THE LIKELY TIGHT GRADIENT
IN SNOWFALL. GIVEN THE LARGE VALUES OF LOW-LEVEL INSTABILITY
PRESENT...SEE NO REASON WHY SOME HIGHER AMOUNTS IN EXCESS OF TEN
INCHES TOWARDS 15 INCHES WOULD NOT BE OBSERVED IF THE BAND WERE
TO BE AS SLOW MOVING AFTER 9 PM AS FORECAST. WINDS GUSTING TO 40
MPH OR HIGHER ARE FAVORED BY OVERNIGHT IN NORTHWEST INDIANA DUE TO
THE LONG FRICTIONLESS FETCH OFF THE LAKE OF THE WIND COMPONENT AND
THE ENHANCED MIXING. THAT WILL AID IN NEAR WHITEOUT CONDITIONS AT
TIMES ACROSS NAMELY LAKE AND PORTER COUNTIES.
OVERALL NO CHANGES MADE TO THE GOING HEADLINES AT THIS TIME. THE
TIMING OF SNOW DEPARTURE IN PORTER COUNTY LOOKS TO BE BETWEEN 8 AM
AND NOON ON SATURDAY...SO THE TIMING OF ENDING THE HEADLINES LOOKS
GOOD. CLEARING TONIGHT HAS BEEN SLOWED IN THE FORECAST...BUT STILL
A STRONG DRY PUSH SHOULD LEAD TO MOST AREAS SEEING SUN BY
DAYBREAK SATURDAY.
MTF
SUNDAY THROUGH FRIDAY
PRIMARY CONCERN IS WHAT IS LOOKING TO BE A LONG DURATION LIGHT SNOW
EVENT ON MONDAY INTO EARLY TUESDAY. GENERALLY STAYED CLOSE TO BLEND
OF GUIDANCE AND PREVIOUS FORECAST THEREAFTER DUE TO LARGE MODEL
DIFFERENCES AND UNCERTAINTY.
SUNDAY THROUGH TUESDAY...
AFTER COLD START TO SUNDAY ON NORTHERN EDGE OF LARGE OF HIGH
PRESSURE...FULL SUN AND H85 TEMPERATURES WARMING TO -6 OR SO SHOULD
ALLOW RECOVERY TO 20S TO AROUND 30 DEGREES...WITH LOW 30S IN
DOWNTOWN CHICAGO. LIMITING FACTOR WILL BE NEW...DEEP SNOW COVER OVER
NORTHERN PORTIONS OF NW INDIANA...SO EXPECTING MID 20S THERE. IN
GENERAL...HIGH TEMPERATURES ARE CLOSE TO MOS GUIDANCE. ON SUNDAY
NIGHT...SHOULD BE UNDER RIDGE AXIS AND WITH CLEAR
SKIES AND DIMINISHED WINDS...TEMPERATURES WILL LIKELY FALL TO NEAR
OR BELOW NORMAL LEVELS DESPITE WARMING ALOFT. COLDEST TEMPERATURES
AGAIN EXPECTED FOR DEEP SNOW COVER AREA IN NORTHWEST INDIANA...WHERE
I WENT BELOW GUIDANCE AND FORECASTED LOW TEENS IN PORTER COUNTY.
CLOUDS WILL LIKELY INCREASE TOWARD DAYBREAK ACROSS NORTHWEST AND
NORTH CENTRAL ILLINOIS...SO TEMPERATURE DROP MAY SLOW OR STOP AFTER
INITIAL QUICK FALL AFTER DARK.
ON MONDAY...HIGH PRESSURE RIDGE WILL LOSE INFLUENCE OVER AREA AS WE
ENTER A PERSISTENT ISENTROPIC ASCENT/WARM ADVECTION
REGIME...ALLOWING INCREASE IN CLOUD COVER FIRST AND THEN
OVERSPREADING OF WIDESPREAD LIGHT PRECIPITATION. AFTER LATEST ECMWF
CAME IN A BIT SLOWER WITH PRECIP...SOME CONCERNS THAT POPS MAY HAVE
TO BE TRIMMED BACK/SLOWED SOME IN NORTHERN ILLINOIS MONDAY MONDAY MORNING
THROUGH NOON. NONETHELESS...AFOREMENTIONED ISENTROPIC ASCENT ALONG
WITH SOME MODEST MID AND UPPER LEVEL SUPPORT FROM MIDLEVEL TROUGH
PIVOTING THROUGH UPPER MIDWEST WILL BRING ENOUGH OMEGA THROUGH
SATURATED COLUMN FOR DECENT SNOW CRYSTAL GROWTH. COLD START TO DAY
PLUS H85 TEMPERATURES REMAINING AT -5C OR LESS THROUGH THE EVENT
WILL ENSURE PRECIP FALLS AS ALL SNOW. AFTERNOON TEMPS SHOULD TOP OUT
NEAR OR SLIGHTLY ABOVE 30F. BASED ON CURRENT PROGGED TRACK OF H5
TROUGH...BEST FORCING LOOKS LIKE IT WILL LINE UP CLOSER TO WISCONSIN
BORDER...BUT GOOD MODEL AGREEMENT LENT ENOUGH CONFIDENCE IN
WIDESPREAD PRECIP FOR ENTIRE CWA TO RAISE POPS TO LIKELY ACROSS THE
AREA INTO MONDAY NIGHT...TAPERING OFF OVERNIGHT INTO TUESDAY.
OVERALL...LOOKING LIKE A LIGHT QPF EVENT...PROBABLY STAYING BELOW
0.20" LE. THUS IN ALL LIKELIHOOD...IT WONT BE A BIG SNOW EVENT...BUT
POTENTIAL EXISTS FOR A COUPLE INCHES FOR AT LEAST A PORTION OF
CWA...WITH RATIOS SLIGHTLY ABOVE 10:1. HAVE LINGERING SLIGHT POPS ON
TUESDAY DUE TO UPPER TROUGH AXIS STAYING NEARBY...WITH TEMPERATURES
MODERATING A BIT MORE.
WEDNESDAY THROUGH FRIDAY...
POLAR VORTEX FULLY RETREATS INTO NORTHERN
CANADA...BRINGING US BACK TO A ZONAL...PACIFIC DOMINATED JET STREAM
PATTERN...ALLOWING TEMPERATURES TO WARM BACK ABOVE NORMAL LEVELS.
WARMING COULD BE LIMITED BY LINGERING SNOW COVER...BUT 40S ARE
CERTAINLY POSSIBLE DURING THE PERIOD...WITH H85 TEMPS WARMING TO AT
OR ABOVE 0C. AS MENTIONED...HOWEVER...LARGE MODEL DIFFERENCES AND
UNCERTAINTY ON MIDLEVEL AND SURFACE FEATURES...WITH ECMWF BRINGING
MIDLEVEL LOW AND SURFACE REFLECTION ACROSS AREA WEDNESDAY INTO
THURSDAY...WHILE GFS HAS A DRY LOOK TO IT. HAVE SLIGHT TO LOW END
CHANCE POPS FROM ALL BLEND DURING THIS PERIOD AND A RAIN OR SNOW
MENTION DUE TO MARGINAL AT BEST THERMAL PROFILE.
RC
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* NORTH-NORTHWEST WINDS GUSTING 25-30 KT THROUGH MUCH OF THE NIGHT
WHILE POSSIBLY EASING TO 20-25 KT IN THE MORNING.
MDB
//DISCUSSION...UPDATED 06Z...
VERY WELL ORGANIZED NORTH-SOUTH LAKE EFFECT SNOW BAND CONTINUES TO
BRING VERY HEAVY SNOW IN THE NORTHWEST INDIANA. GYY REMAINS JUST
TO THE WEST OF THE BAND WITH PERIODS OF LIGHT SNOW BUT THE BAND
DOES CONTINUE TO WOBBLE EAST AND WEST SLIGHTLY KEEPING THE
POTNEITAL FOR SHORT PERIODS OF MORE INTENSE SNOWFALL TO THE
TERMINAL OF THE SEVERAL HOURS. THE BAND WILL LIKELY BEGIN TO SHIFT
MORE TO THE EAST OVERNIGHT ALLOWING SNOW TO END AT GYY...BUT IT IS
NOT CLEAR WHEN EXACTLY THIS WILL OCCUR. NORTHWEST WINDS GUSTING
ANYWHERE FROM 30 TO NEAR 40 KT AT TIMES WILL CAUSE BLOWING AND
DRIFTING AND KEEP VSBY LIMITED EVEN WHEN SNOW IS NOT FALLING.
ELSEHWERE...VFR HAS SPREAD ACROSS THE NORTHERN ILLINOIS TERMINALS
AND WILL CONTINUE OVERNIGHT. NORTH-NORTHWEST WINDS CONTINUE TO
GUST INTO THE 25-30 KT RANGE AT THE CHI METRO TERMINALS THANKS TO
TIGHT PRESSURE GRADIENT CLOSER TO THE LAKE. SPEEDS MAY EASE OFF A
BIT BUT LIKELY REMAIN GUSTY SATURDAY MORNING WHILE TURNING A BIT
MORE WESTERLY. GUSTS TO AROUND 25 KT ARE EXPECTED DURING THE
AFTERNOON. VFR CONDITIONS EXPECTED TO PREVAIL WITH AN UPPER LEVEL
WAVE BRINGING SOME MID CLOUD COVER AT TIMES DURING THE DAY. THE
VERY DRY LOW LEVELS SHOULD PRECLUDE ANY STRATO CU DEVELOPMENT. WINDS
WILL EASE SOMEWHAT SATURDAY EVENING.
MDB
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* HIGH CONFIDENCE IN NORTH-NORTHWEST WINDS GUSTING 25-30 KT
THROUGH MUCH OF THE NIGHT BUT LOW-MEDIUM CONFIDENCE IN GUST
SPEEDS SATURDAY MORNING AND AFTERNOON.
MDB
//OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z...
SUNDAY...VFR.
MONDAY/TUESDAY...LIGHT SNOW LIKELY WITH IFR POSSIBLE.
WEDNESDAY...VFR.
THURSDAY...CHANCE OF RAIN AND SNOW.
MDB
&&
.MARINE...
156 PM CST
THE MAIN CONCERNS CONTINUE TO FOCUS ON THE STRONG WINDS ACROSS LAKE
MICHIGAN TONIGHT INTO SATURDAY. THE STRONG SURFACE COLD FRONT IS
MOVING ACROSS THE SOUTHERN TIP OF LAKE MICHIGAN EARLY THIS
AFTERNOON. I EXPECT NORTHERLY GALE FORCE WINDS AROUND 35 KNOTS IN
THE WAKE OF THIS FRONT. AS VERY COLD AIR CONTINUES TO SPILL OVER THE
LAKE THIS EVENING...A FAVORABLE THERMODYNAMIC SETUP WILL OCCUR FOR A
BANDS OF INTENSE LAKE EFFECT SNOW TO DEVELOP. THERE IS ALSO A GOOD
POSSIBILITY THAT AS SOME AREAS ACROSS THE SOUTHERN END OF THE LAKE
MAY SEE GALES INCREASE TO 40 KT FOR A PERIOD TONIGHT AS THESE
CONVERGENT BANDS OF SNOW DEVELOP. THESE STRONG WINDS WILL LIKELY
ALSO AFFECT THE INDIANA NEAR SHORE WATERS.
WINDS WILL ABATE SOME ON SATURDAY. HOWEVER...THE PRESSURE GRADIENT
WILL REMAIN FAIRLY TIGHT ACROSS THE LAKE AS HIGH PRESSURE DROPS OUT
OF SOUTHERN CANADA AND BUILDS ACROSS THE LOWER AND MIDDLE MISSOURI
RIVER VALLEY. THEREFORE...EXPECT NORTHWEST WINDS TO 30 KT TO
CONTINUE ON SATURDAY AND SATURDAY NIGHT. THIS SURFACE HIGH WILL
BUILD EASTWARD ACROSS THE OHIO VALLEY ON SUNDAY AND SUNDAY NIGHT.
ONCE THIS OCCURS THE WINDS WILL BECOME WEST SOUTHWESTERLY BY MONDAY.
WIND SPEEDS WILL DIMINISH INTO MONDAY.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...BLIZZARD WARNING...INZ002 UNTIL 9 AM SATURDAY.
LAKE EFFECT SNOW WARNING...INZ001 UNTIL 4 AM SATURDAY.
LAKE EFFECT SNOW WARNING...INZ011 UNTIL 9 AM SATURDAY.
LM...GALE WARNING...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-
LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 AM
SATURDAY.
GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565 UNTIL 6
AM SATURDAY.
GALE WARNING...ILLINOIS NEARSHORE WATERS UNTIL 4 AM SATURDAY.
SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742...4 AM SATURDAY TO 6
AM SUNDAY.
GALE WARNING...INDIANA NEARSHORE WATERS UNTIL 10 AM SATURDAY.
SMALL CRAFT ADVISORY...LMZ743-LMZ744-LMZ745...10 AM SATURDAY TO
2 PM SUNDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1100 PM CST FRI FEB 10 2012
.DISCUSSION...
1008 PM CST
REMAINING ADVISORIES HAVE BEEN ALLOWED TO EXPIRE THIS
EVENING...HAVE CONTINUED LAKE EFFECT WARNING FOR LAKE AND PORTER
IN INDIANA...AND HAVE UPGRADED JASPER COUNTY TO A LAKE EFFECT
WARNING.
LATEST RADAR ANALYSIS CONTINUES TO SHOW LAKE EFFECT SNOW SHOWERS
DEVELOPING BUT PRIMARILY REMAINING IN INDIANA...WITH THE MORE
SYNOPTICALLY DRIVEN SNOW HAVING SINCE DIMINISHED OVER THE LAST
COUPLE OF THE HOURS. LATEST TRENDS IN LINE WITH CURRENT HEADLINES
IN PLACE WITH LAKE EFFECT SNOW SHOWERS CONTINUING OVERNIGHT. OVER
THE LAST COUPLE OF HOURS...A STRONGER AND MORE DEFINED SNOW BAND
HAS DEVELOPED AND SITUATED ITSELF OVER LAKE AND PORTER COUNTIES IN
INDIANA. LATEST RUC ANALYSIS SHOWING CONDITIONS OVER THE LAKE HAVE
IMPROVED SIGNIFICANTLY IN REGARDS TO SNOW POTENTIAL WITH 850 DELTA
TS IN UPWARDS OF 18C AND STRONG CONVERGENCE SETTING UP ACROSS THE
LAKE...AS ALSO INDICATED BY LATEST SURFACE/MARINE OBS. LATEST
GUIDANCE IN GOOD AGREEMENT WITH CONDITIONS OVER THE LAKE TO
CONTINUE IMPROVING OVER THE NEXT SEVERAL HOURS. THIS COINCIDING
WITH A LONG FETCH OVER THE LAKE AND DECENT INVERSION
HEIGHTS...SHOULD ALLOW FOR CONTINUED DEVELOPMENT INTO THE EARLY
MORNING HOURS ON SATURDAY. SHORT RANGE GUIDANCE IS INDICATING THAT
THIS BAND WILL REMAIN SITUATED OVER THE LAKE/PORTER COUNTY LINE
BEFORE LOW LEVEL/BOUNDARY LAYER FLOW SHIFTS MORE EAST AND HELPS
STEER IT MORE OVER PORTER COUNTY BY THE EARLY MORNING HOURS. HAVE
INCREASE SNOW AMOUNTS ACROSS JASPER COUNTY AS LATEST RADAR RETURNS
HAVE BEEN REACHING THE NORTHERN PORTIONS OF THE COUNTY. WITH
CONDITIONS EXPECTED TO ONLY BECOME MORE FAVORABLE TONIGHT AND WITH
STRONG FLOW IN PLACE...PORTIONS OF JASPER COUNTY SHOULD SEE
WARNING CRITERIA SNOW. FORECASTED SNOW AMOUNTS CONTINUE TO BE IN
LINE WITH THE HIGHEST AMOUNTS STILL EXPECTED WITHIN PORTER
COUNTY...BEFORE THIS BAND SHIFTS EAST WITH TIME SATURDAY MORNING.
RODRIGUEZ
//PREV DISCUSSION...
355 PM CST
THE ONGOING SNOW EVENT WILL TRANSITION TO MORE OF A TRUE LAKE
EFFECT SNOW STORM INTO MAINLY NORTHWEST INDIANA THIS EVENING. THE
COMBINATION OF THE SNOW...GUSTY WINDS...AND FALLING TEMPERATURES
FREEZING SOME OF THE EARLIER MELTED SNOWFALL WILL CONTINUE TO
CREATE IMPACTS FOR A LARGE PART OF THE AREA INTO EARLY
EVENING...AND NORTHWEST INDIANA ALL NIGHT LONG.
LATE THIS AFTERNOON THROUGH SATURDAY
THE ARCTIC FRONT WILL CONTINUE TO MOVE SOUTHWARD...CLEARING THE
AREA BY EARLY EVENING. NORTHERLY WINDS GUSTING UP TO 35 MPH HAVE
USHERED IN A MUCH COLDER AIR ACROSS THE AREA WITH WIND CHILLS
HAVING DROPPED TO NEAR ZERO ALREADY ALONG THE WI STATE LINE. WATER
VAPOR SATELLITE SHOWS THE MAIN UPPER LEVEL WAVE MOVING OVER THE
AREA...WHICH COMBINED WITH THE STEEP LOW-LEVEL LAPSE RATES WILL
CONTINUE GENERAL SNOWFALL ACROSS THE IL AREA THROUGH EARLY TO MID
EVENING. SOME LAKE ENHANCEMENT IMMEDIATELY NEAR THE LAKE MICHIGAN
SHORE IS LIKELY.
A TRUE LAKE EFFECT BAND HAS ALREADY DEVELOPED JUST OFFSHORE BASED
ON KMKX/TORD RADAR SIGNATURES. THIS WILL CONTINUE TO BECOME
BETTER ESTABLISHED INTO COOK AND NORTHWEST LAKE COUNTIES THROUGH
EARLY EVENING BASED ON SHORT TERM GUIDANCE DEPICTION OF LOW-LEVEL
CONVERGENCE AND INSTABILITY. BY 9 PM AND AFTER...THE
EMPHASIS WILL BE SHIFTING INTO FAR SOUTHEAST COOK AND LAKE
COUNTIES WITH HIGH CONFIDENCE IN SHORT TERM MODELS. IT IS POSSIBLE
THE ADVISORY WILL NEED TO BE EXTENDED FOR COOK COUNTY AFTER 9
PM...AS SNOWFALL RATES WITHIN SUCH A BAND ARE LIKELY TO BE HEAVY
WITH EFFICIENT SNOW-TO-LIQUID RATIOS AND THE PRESENT INSTABILITY.
THE STRONG TEMPERATURE DIFFERENCE BETWEEN THE AIR MOVING OVER THE
LAKE AND THE 38 TO 43 DEGREE OPEN WATER LAKE TEMPERATURES ACROSS
THE SOUTHERN HALF WILL HELP TO GENERATE LAKE-INDUCED CAPE VALUES
TO 500 J/KG BY AFTER 9 PM...LASTING THROUGH THE OVERNIGHT AND
SHIFTING SLOWLY EAST. FAR SOUTHEAST COOK COUNTY COULD SEE TOTAL
SNOWFALL AMOUNTS APPROACH SIX INCHES.
THE CONVERGENT AXIS WILL ROTATE EAST FOCUSING INTO LAKE AND PORTER
COUNTIES OVERNIGHT. THE RATIOS SHOULD CONTINUE TO INCREASE...WITH
THE FAVORABLE SNOW GROWTH ZONE LOCATED BELOW THE EQUILIBRIUM
LEVEL. THE HIGHER WIND SPEEDS ARE LIKELY TO BREAK UP THE FLAKES
SOME...BUT THE HEAVY RATES SHOULD STILL COMPENSATE FOR THAT.
SIMULATED REFLECTIVITY ON SHORT TERM GUIDANCE ALSO RAMPS UP DURING
THAT TIME. THE TREND WITH ALMOST ALL HIGH RESOLUTION GUIDANCE WAS
TO SHIFT THIS EAST SLIGHTLY...REALLY FOCUSING INTO PORTER COUNTY
OVERNIGHT. THE HIGHEST SNOWFALL AMOUNTS TOWARD TEN INCHES IN OUR
FORECAST ARE FOCUSED IN EASTERN LAKE AND PORTER COUNTIES. THE
WIDTH OF THE BAND LOOKS TO NARROW AS IT SHIFTS EAST THOUGH...SO
AGAIN SOME UNCERTAINTY CONTINUES DUE TO THE LIKELY TIGHT GRADIENT
IN SNOWFALL. GIVEN THE LARGE VALUES OF LOW-LEVEL INSTABILITY
PRESENT...SEE NO REASON WHY SOME HIGHER AMOUNTS IN EXCESS OF TEN
INCHES TOWARDS 15 INCHES WOULD NOT BE OBSERVED IF THE BAND WERE
TO BE AS SLOW MOVING AFTER 9 PM AS FORECAST. WINDS GUSTING TO 40
MPH OR HIGHER ARE FAVORED BY OVERNIGHT IN NORTHWEST INDIANA DUE TO
THE LONG FRICTIONLESS FETCH OFF THE LAKE OF THE WIND COMPONENT AND
THE ENHANCED MIXING. THAT WILL AID IN NEAR WHITEOUT CONDITIONS AT
TIMES ACROSS NAMELY LAKE AND PORTER COUNTIES.
OVERALL NO CHANGES MADE TO THE GOING HEADLINES AT THIS TIME. THE
TIMING OF SNOW DEPARTURE IN PORTER COUNTY LOOKS TO BE BETWEEN 8 AM
AND NOON ON SATURDAY...SO THE TIMING OF ENDING THE HEADLINES LOOKS
GOOD. CLEARING TONIGHT HAS BEEN SLOWED IN THE FORECAST...BUT STILL
A STRONG DRY PUSH SHOULD LEAD TO MOST AREAS SEEING SUN BY
DAYBREAK SATURDAY.
MTF
SUNDAY THROUGH FRIDAY
PRIMARY CONCERN IS WHAT IS LOOKING TO BE A LONG DURATION LIGHT SNOW
EVENT ON MONDAY INTO EARLY TUESDAY. GENERALLY STAYED CLOSE TO BLEND
OF GUIDANCE AND PREVIOUS FORECAST THEREAFTER DUE TO LARGE MODEL
DIFFERENCES AND UNCERTAINTY.
SUNDAY THROUGH TUESDAY...
AFTER COLD START TO SUNDAY ON NORTHERN EDGE OF LARGE OF HIGH
PRESSURE...FULL SUN AND H85 TEMPERATURES WARMING TO -6 OR SO SHOULD
ALLOW RECOVERY TO 20S TO AROUND 30 DEGREES...WITH LOW 30S IN
DOWNTOWN CHICAGO. LIMITING FACTOR WILL BE NEW...DEEP SNOW COVER OVER
NORTHERN PORTIONS OF NW INDIANA...SO EXPECTING MID 20S THERE. IN
GENERAL...HIGH TEMPERATURES ARE CLOSE TO MOS GUIDANCE. ON SUNDAY
NIGHT...SHOULD BE UNDER RIDGE AXIS AND WITH CLEAR
SKIES AND DIMINISHED WINDS...TEMPERATURES WILL LIKELY FALL TO NEAR
OR BELOW NORMAL LEVELS DESPITE WARMING ALOFT. COLDEST TEMPERATURES
AGAIN EXPECTED FOR DEEP SNOW COVER AREA IN NORTHWEST INDIANA...WHERE
I WENT BELOW GUIDANCE AND FORECASTED LOW TEENS IN PORTER COUNTY.
CLOUDS WILL LIKELY INCREASE TOWARD DAYBREAK ACROSS NORTHWEST AND
NORTH CENTRAL ILLINOIS...SO TEMPERATURE DROP MAY SLOW OR STOP AFTER
INITIAL QUICK FALL AFTER DARK.
ON MONDAY...HIGH PRESSURE RIDGE WILL LOSE INFLUENCE OVER AREA AS WE
ENTER A PERSISTENT ISENTROPIC ASCENT/WARM ADVECTION
REGIME...ALLOWING INCREASE IN CLOUD COVER FIRST AND THEN
OVERSPREADING OF WIDESPREAD LIGHT PRECIPITATION. AFTER LATEST ECMWF
CAME IN A BIT SLOWER WITH PRECIP...SOME CONCERNS THAT POPS MAY HAVE
TO BE TRIMMED BACK/SLOWED SOME IN NORTHERN ILLINOIS MONDAY MONDAY MORNING
THROUGH NOON. NONETHELESS...AFOREMENTIONED ISENTROPIC ASCENT ALONG
WITH SOME MODEST MID AND UPPER LEVEL SUPPORT FROM MIDLEVEL TROUGH
PIVOTING THROUGH UPPER MIDWEST WILL BRING ENOUGH OMEGA THROUGH
SATURATED COLUMN FOR DECENT SNOW CRYSTAL GROWTH. COLD START TO DAY
PLUS H85 TEMPERATURES REMAINING AT -5C OR LESS THROUGH THE EVENT
WILL ENSURE PRECIP FALLS AS ALL SNOW. AFTERNOON TEMPS SHOULD TOP OUT
NEAR OR SLIGHTLY ABOVE 30F. BASED ON CURRENT PROGGED TRACK OF H5
TROUGH...BEST FORCING LOOKS LIKE IT WILL LINE UP CLOSER TO WISCONSIN
BORDER...BUT GOOD MODEL AGREEMENT LENT ENOUGH CONFIDENCE IN
WIDESPREAD PRECIP FOR ENTIRE CWA TO RAISE POPS TO LIKELY ACROSS THE
AREA INTO MONDAY NIGHT...TAPERING OFF OVERNIGHT INTO TUESDAY.
OVERALL...LOOKING LIKE A LIGHT QPF EVENT...PROBABLY STAYING BELOW
0.20" LE. THUS IN ALL LIKELIHOOD...IT WONT BE A BIG SNOW EVENT...BUT
POTENTIAL EXISTS FOR A COUPLE INCHES FOR AT LEAST A PORTION OF
CWA...WITH RATIOS SLIGHTLY ABOVE 10:1. HAVE LINGERING SLIGHT POPS ON
TUESDAY DUE TO UPPER TROUGH AXIS STAYING NEARBY...WITH TEMPERATURES
MODERATING A BIT MORE.
WEDNESDAY THROUGH FRIDAY...
POLAR VORTEX FULLY RETREATS INTO NORTHERN
CANADA...BRINGING US BACK TO A ZONAL...PACIFIC DOMINATED JET STREAM
PATTERN...ALLOWING TEMPERATURES TO WARM BACK ABOVE NORMAL LEVELS.
WARMING COULD BE LIMITED BY LINGERING SNOW COVER...BUT 40S ARE
CERTAINLY POSSIBLE DURING THE PERIOD...WITH H85 TEMPS WARMING TO AT
OR ABOVE 0C. AS MENTIONED...HOWEVER...LARGE MODEL DIFFERENCES AND
UNCERTAINTY ON MIDLEVEL AND SURFACE FEATURES...WITH ECMWF BRINGING
MIDLEVEL LOW AND SURFACE REFLECTION ACROSS AREA WEDNESDAY INTO
THURSDAY...WHILE GFS HAS A DRY LOOK TO IT. HAVE SLIGHT TO LOW END
CHANCE POPS FROM ALL BLEND DURING THIS PERIOD AND A RAIN OR SNOW
MENTION DUE TO MARGINAL AT BEST THERMAL PROFILE.
RC
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* NORTH-NORTHWEST WINDS GUSTING 25-30 KT THROUGH MUCH OF THE NIGHT
WHILE POSSIBLY EASING TO 20-25 KT IN THE MORNING.
MDB
//DISCUSSION...UPDATED 06Z...
VERY WELL ORGANIZED NORTH-SOUTH LAKE EFFECT SNOW BAND CONTINUES TO
BRING VERY HEAVY SNOW IN THE NORTHWEST INDIANA. GYY REMAINS JUST
TO THE WEST OF THE BAND WITH PERIODS OF LIGHT SNOW BUT THE BAND
DOES CONTINUE TO WOBBLE EAST AND WEST SLIGHTLY KEEPING THE
POTNEITAL FOR SHORT PERIODS OF MORE INTENSE SNOWFALL TO THE
TERMINAL OF THE SEVERAL HOURS. THE BAND WILL LIKELY BEGIN TO SHIFT
MORE TO THE EAST OVERNIGHT ALLOWING SNOW TO END AT GYY...BUT IT IS
NOT CLEAR WHEN EXACTLY THIS WILL OCCUR. NORTHWEST WINDS GUSTING
ANYWHERE FROM 30 TO NEAR 40 KT AT TIMES WILL CAUSE BLOWING AND
DRIFTING AND KEEP VSBY LIMITED EVEN WHEN SNOW IS NOT FALLING.
ELSEHWERE...VFR HAS SPREAD ACROSS THE NORTHERN ILLINOIS TERMINALS
AND WILL CONTINUE OVERNIGHT. NORTH-NORTHWEST WINDS CONTINUE TO
GUST INTO THE 25-30 KT RANGE AT THE CHI METRO TERMINALS THANKS TO
TIGHT PRESSURE GRADIENT CLOSER TO THE LAKE. SPEEDS MAY EASE OFF A
BIT BUT LIKELY REMAIN GUSTY SATURDAY MORNING WHILE TURNING A BIT
MORE WESTERLY. GUSTS TO AROUND 25 KT ARE EXPECTED DURING THE
AFTERNOON. VFR CONDITIONS EXPECTED TO PREVAIL WITH AN UPPER LEVEL
WAVE BRINGING SOME MID CLOUD COVER AT TIMES DURING THE DAY. THE
VERY DRY LOW LEVELS SHOULD PRECLUDE ANY STRATO CU DEVELOPMENT. WINDS
WILL EASE SOMEWHAT SATURDAY EVENING.
MDB
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* HIGH CONFIDENCE IN NORTH-NORTHWEST WINDS GUSTING 25-30 KT
THROUGH MUCH OF THE NIGHT BUT LOW-MEDIUM CONFIDENCE IN GUST
SPEEDS SATURDAY MORNING AND AFTERNOON.
MDB
//OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z...
SUNDAY...VFR.
MONDAY/TUESDAY...LIGHT SNOW LIKELY WITH IFR POSSIBLE.
WEDNESDAY...VFR.
THURSDAY...CHANCE OF RAIN AND SNOW.
MDB
&&
.MARINE...
156 PM CST
THE MAIN CONCERNS CONTINUE TO FOCUS ON THE STRONG WINDS ACROSS LAKE
MICHIGAN TONIGHT INTO SATURDAY. THE STRONG SURFACE COLD FRONT IS
MOVING ACROSS THE SOUTHERN TIP OF LAKE MICHIGAN EARLY THIS
AFTERNOON. I EXPECT NORTHERLY GALE FORCE WINDS AROUND 35 KNOTS IN
THE WAKE OF THIS FRONT. AS VERY COLD AIR CONTINUES TO SPILL OVER THE
LAKE THIS EVENING...A FAVORABLE THERMODYNAMIC SETUP WILL OCCUR FOR A
BANDS OF INTENSE LAKE EFFECT SNOW TO DEVELOP. THERE IS ALSO A GOOD
POSSIBILITY THAT AS SOME AREAS ACROSS THE SOUTHERN END OF THE LAKE
MAY SEE GALES INCREASE TO 40 KT FOR A PERIOD TONIGHT AS THESE
CONVERGENT BANDS OF SNOW DEVELOP. THESE STRONG WINDS WILL LIKELY
ALSO AFFECT THE INDIANA NEAR SHORE WATERS.
WINDS WILL ABATE SOME ON SATURDAY. HOWEVER...THE PRESSURE GRADIENT
WILL REMAIN FAIRLY TIGHT ACROSS THE LAKE AS HIGH PRESSURE DROPS OUT
OF SOUTHERN CANADA AND BUILDS ACROSS THE LOWER AND MIDDLE MISSOURI
RIVER VALLEY. THEREFORE...EXPECT NORTHWEST WINDS TO 30 KT TO
CONTINUE ON SATURDAY AND SATURDAY NIGHT. THIS SURFACE HIGH WILL
BUILD EASTWARD ACROSS THE OHIO VALLEY ON SUNDAY AND SUNDAY NIGHT.
ONCE THIS OCCURS THE WINDS WILL BECOME WEST SOUTHWESTERLY BY MONDAY.
WIND SPEEDS WILL DIMINISH INTO MONDAY.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...LAKE EFFECT SNOW WARNING...INZ001 UNTIL 4 AM SATURDAY.
LAKE EFFECT SNOW WARNING...INZ002-INZ011 UNTIL 9 AM SATURDAY.
LM...GALE WARNING...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-
LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 AM
SATURDAY.
GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565 UNTIL 6
AM SATURDAY.
GALE WARNING...ILLINOIS NEARSHORE WATERS UNTIL 4 AM SATURDAY.
SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742...4 AM SATURDAY TO 6
AM SUNDAY.
GALE WARNING...INDIANA NEARSHORE WATERS UNTIL 10 AM SATURDAY.
SMALL CRAFT ADVISORY...LMZ743-LMZ744-LMZ745...10 AM SATURDAY TO
2 PM SUNDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1009 PM CST FRI FEB 10 2012
.DISCUSSION...
1008 PM CST
REMAINING ADVISORIES HAVE BEEN ALLOWED TO EXPIRE THIS
EVENING...HAVE CONTINUED LAKE EFFECT WARNING FOR LAKE AND PORTER
IN INDIANA...AND HAVE UPGRADED JASPER COUNTY TO A LAKE EFFECT
WARNING.
LATEST RADAR ANALYSIS CONTINUES TO SHOW LAKE EFFECT SNOW SHOWERS
DEVELOPING BUT PRIMARILY REMAINING IN INDIANA...WITH THE MORE
SYNOPTICALLY DRIVEN SNOW HAVING SINCE DIMINISHED OVER THE LAST
COUPLE OF THE HOURS. LATEST TRENDS IN LINE WITH CURRENT HEADLINES
IN PLACE WITH LAKE EFFECT SNOW SHOWERS CONTINUING OVERNIGHT. OVER
THE LAST COUPLE OF HOURS...A STRONGER AND MORE DEFINED SNOW BAND
HAS DEVELOPED AND SITUATED ITSELF OVER LAKE AND PORTER COUNTIES IN
INDIANA. LATEST RUC ANALYSIS SHOWING CONDITIONS OVER THE LAKE HAVE
IMPROVED SIGNIFICANTLY IN REGARDS TO SNOW POTENTIAL WITH 850 DELTA
TS IN UPWARDS OF 18C AND STRONG CONVERGENCE SETTING UP ACROSS THE
LAKE...AS ALSO INDICATED BY LATEST SURFACE/MARINE OBS. LATEST
GUIDANCE IN GOOD AGREEMENT WITH CONDITIONS OVER THE LAKE TO
CONTINUE IMPROVING OVER THE NEXT SEVERAL HOURS. THIS COINCIDING
WITH A LONG FETCH OVER THE LAKE AND DECENT INVERSION
HEIGHTS...SHOULD ALLOW FOR CONTINUED DEVELOPMENT INTO THE EARLY
MORNING HOURS ON SATURDAY. SHORT RANGE GUIDANCE IS INDICATING THAT
THIS BAND WILL REMAIN SITUATED OVER THE LAKE/PORTER COUNTY LINE
BEFORE LOW LEVEL/BOUNDARY LAYER FLOW SHIFTS MORE EAST AND HELPS
STEER IT MORE OVER PORTER COUNTY BY THE EARLY MORNING HOURS. HAVE
INCREASE SNOW AMOUNTS ACROSS JASPER COUNTY AS LATEST RADAR RETURNS
HAVE BEEN REACHING THE NORTHERN PORTIONS OF THE COUNTY. WITH
CONDITIONS EXPECTED TO ONLY BECOME MORE FAVORABLE TONIGHT AND WITH
STRONG FLOW IN PLACE...PORTIONS OF JASPER COUNTY SHOULD SEE
WARNING CRITERIA SNOW. FORECASTED SNOW AMOUNTS CONTINUE TO BE IN
LINE WITH THE HIGHEST AMOUNTS STILL EXPECTED WITHIN PORTER
COUNTY...BEFORE THIS BAND SHIFTS EAST WITH TIME SATURDAY MORNING.
RODRIGUEZ
&&
.PREV DISCUSSION...
355 PM CST
THE ONGOING SNOW EVENT WILL TRANSITION TO MORE OF A TRUE LAKE
EFFECT SNOW STORM INTO MAINLY NORTHWEST INDIANA THIS EVENING. THE
COMBINATION OF THE SNOW...GUSTY WINDS...AND FALLING TEMPERATURES
FREEZING SOME OF THE EARLIER MELTED SNOWFALL WILL CONTINUE TO
CREATE IMPACTS FOR A LARGE PART OF THE AREA INTO EARLY
EVENING...AND NORTHWEST INDIANA ALL NIGHT LONG.
LATE THIS AFTERNOON THROUGH SATURDAY
THE ARCTIC FRONT WILL CONTINUE TO MOVE SOUTHWARD...CLEARING THE
AREA BY EARLY EVENING. NORTHERLY WINDS GUSTING UP TO 35 MPH HAVE
USHERED IN A MUCH COLDER AIR ACROSS THE AREA WITH WIND CHILLS
HAVING DROPPED TO NEAR ZERO ALREADY ALONG THE WI STATE LINE. WATER
VAPOR SATELLITE SHOWS THE MAIN UPPER LEVEL WAVE MOVING OVER THE
AREA...WHICH COMBINED WITH THE STEEP LOW-LEVEL LAPSE RATES WILL
CONTINUE GENERAL SNOWFALL ACROSS THE IL AREA THROUGH EARLY TO MID
EVENING. SOME LAKE ENHANCEMENT IMMEDIATELY NEAR THE LAKE MICHIGAN
SHORE IS LIKELY.
A TRUE LAKE EFFECT BAND HAS ALREADY DEVELOPED JUST OFFSHORE BASED
ON KMKX/TORD RADAR SIGNATURES. THIS WILL CONTINUE TO BECOME
BETTER ESTABLISHED INTO COOK AND NORTHWEST LAKE COUNTIES THROUGH
EARLY EVENING BASED ON SHORT TERM GUIDANCE DEPICTION OF LOW-LEVEL
CONVERGENCE AND INSTABILITY. BY 9 PM AND AFTER...THE
EMPHASIS WILL BE SHIFTING INTO FAR SOUTHEAST COOK AND LAKE
COUNTIES WITH HIGH CONFIDENCE IN SHORT TERM MODELS. IT IS POSSIBLE
THE ADVISORY WILL NEED TO BE EXTENDED FOR COOK COUNTY AFTER 9
PM...AS SNOWFALL RATES WITHIN SUCH A BAND ARE LIKELY TO BE HEAVY
WITH EFFICIENT SNOW-TO-LIQUID RATIOS AND THE PRESENT INSTABILITY.
THE STRONG TEMPERATURE DIFFERENCE BETWEEN THE AIR MOVING OVER THE
LAKE AND THE 38 TO 43 DEGREE OPEN WATER LAKE TEMPERATURES ACROSS
THE SOUTHERN HALF WILL HELP TO GENERATE LAKE-INDUCED CAPE VALUES
TO 500 J/KG BY AFTER 9 PM...LASTING THROUGH THE OVERNIGHT AND
SHIFTING SLOWLY EAST. FAR SOUTHEAST COOK COUNTY COULD SEE TOTAL
SNOWFALL AMOUNTS APPROACH SIX INCHES.
THE CONVERGENT AXIS WILL ROTATE EAST FOCUSING INTO LAKE AND PORTER
COUNTIES OVERNIGHT. THE RATIOS SHOULD CONTINUE TO INCREASE...WITH
THE FAVORABLE SNOW GROWTH ZONE LOCATED BELOW THE EQUILIBRIUM
LEVEL. THE HIGHER WIND SPEEDS ARE LIKELY TO BREAK UP THE FLAKES
SOME...BUT THE HEAVY RATES SHOULD STILL COMPENSATE FOR THAT.
SIMULATED REFLECTIVITY ON SHORT TERM GUIDANCE ALSO RAMPS UP DURING
THAT TIME. THE TREND WITH ALMOST ALL HIGH RESOLUTION GUIDANCE WAS
TO SHIFT THIS EAST SLIGHTLY...REALLY FOCUSING INTO PORTER COUNTY
OVERNIGHT. THE HIGHEST SNOWFALL AMOUNTS TOWARD TEN INCHES IN OUR
FORECAST ARE FOCUSED IN EASTERN LAKE AND PORTER COUNTIES. THE
WIDTH OF THE BAND LOOKS TO NARROW AS IT SHIFTS EAST THOUGH...SO
AGAIN SOME UNCERTAINTY CONTINUES DUE TO THE LIKELY TIGHT GRADIENT
IN SNOWFALL. GIVEN THE LARGE VALUES OF LOW-LEVEL INSTABILITY
PRESENT...SEE NO REASON WHY SOME HIGHER AMOUNTS IN EXCESS OF TEN
INCHES TOWARDS 15 INCHES WOULD NOT BE OBSERVED IF THE BAND WERE
TO BE AS SLOW MOVING AFTER 9 PM AS FORECAST. WINDS GUSTING TO 40
MPH OR HIGHER ARE FAVORED BY OVERNIGHT IN NORTHWEST INDIANA DUE TO
THE LONG FRICTIONLESS FETCH OFF THE LAKE OF THE WIND COMPONENT AND
THE ENHANCED MIXING. THAT WILL AID IN NEAR WHITEOUT CONDITIONS AT
TIMES ACROSS NAMELY LAKE AND PORTER COUNTIES.
OVERALL NO CHANGES MADE TO THE GOING HEADLINES AT THIS TIME. THE
TIMING OF SNOW DEPARTURE IN PORTER COUNTY LOOKS TO BE BETWEEN 8 AM
AND NOON ON SATURDAY...SO THE TIMING OF ENDING THE HEADLINES LOOKS
GOOD. CLEARING TONIGHT HAS BEEN SLOWED IN THE FORECAST...BUT STILL
A STRONG DRY PUSH SHOULD LEAD TO MOST AREAS SEEING SUN BY
DAYBREAK SATURDAY.
MTF
SUNDAY THROUGH FRIDAY
PRIMARY CONCERN IS WHAT IS LOOKING TO BE A LONG DURATION LIGHT SNOW
EVENT ON MONDAY INTO EARLY TUESDAY. GENERALLY STAYED CLOSE TO BLEND
OF GUIDANCE AND PREVIOUS FORECAST THEREAFTER DUE TO LARGE MODEL
DIFFERENCES AND UNCERTAINTY.
SUNDAY THROUGH TUESDAY...
AFTER COLD START TO SUNDAY ON NORTHERN EDGE OF LARGE OF HIGH
PRESSURE...FULL SUN AND H85 TEMPERATURES WARMING TO -6 OR SO SHOULD
ALLOW RECOVERY TO 20S TO AROUND 30 DEGREES...WITH LOW 30S IN
DOWNTOWN CHICAGO. LIMITING FACTOR WILL BE NEW...DEEP SNOW COVER OVER
NORTHERN PORTIONS OF NW INDIANA...SO EXPECTING MID 20S THERE. IN
GENERAL...HIGH TEMPERATURES ARE CLOSE TO MOS GUIDANCE. ON SUNDAY
NIGHT...SHOULD BE UNDER RIDGE AXIS AND WITH CLEAR
SKIES AND DIMINISHED WINDS...TEMPERATURES WILL LIKELY FALL TO NEAR
OR BELOW NORMAL LEVELS DESPITE WARMING ALOFT. COLDEST TEMPERATURES
AGAIN EXPECTED FOR DEEP SNOW COVER AREA IN NORTHWEST INDIANA...WHERE
I WENT BELOW GUIDANCE AND FORECASTED LOW TEENS IN PORTER COUNTY.
CLOUDS WILL LIKELY INCREASE TOWARD DAYBREAK ACROSS NORTHWEST AND
NORTH CENTRAL ILLINOIS...SO TEMPERATURE DROP MAY SLOW OR STOP AFTER
INITIAL QUICK FALL AFTER DARK.
ON MONDAY...HIGH PRESSURE RIDGE WILL LOSE INFLUENCE OVER AREA AS WE
ENTER A PERSISTENT ISENTROPIC ASCENT/WARM ADVECTION
REGIME...ALLOWING INCREASE IN CLOUD COVER FIRST AND THEN
OVERSPREADING OF WIDESPREAD LIGHT PRECIPITATION. AFTER LATEST ECMWF
CAME IN A BIT SLOWER WITH PRECIP...SOME CONCERNS THAT POPS MAY HAVE
TO BE TRIMMED BACK/SLOWED SOME IN NORTHERN ILLINOIS MONDAY MONDAY MORNING
THROUGH NOON. NONETHELESS...AFOREMENTIONED ISENTROPIC ASCENT ALONG
WITH SOME MODEST MID AND UPPER LEVEL SUPPORT FROM MIDLEVEL TROUGH
PIVOTING THROUGH UPPER MIDWEST WILL BRING ENOUGH OMEGA THROUGH
SATURATED COLUMN FOR DECENT SNOW CRYSTAL GROWTH. COLD START TO DAY
PLUS H85 TEMPERATURES REMAINING AT -5C OR LESS THROUGH THE EVENT
WILL ENSURE PRECIP FALLS AS ALL SNOW. AFTERNOON TEMPS SHOULD TOP OUT
NEAR OR SLIGHTLY ABOVE 30F. BASED ON CURRENT PROGGED TRACK OF H5
TROUGH...BEST FORCING LOOKS LIKE IT WILL LINE UP CLOSER TO WISCONSIN
BORDER...BUT GOOD MODEL AGREEMENT LENT ENOUGH CONFIDENCE IN
WIDESPREAD PRECIP FOR ENTIRE CWA TO RAISE POPS TO LIKELY ACROSS THE
AREA INTO MONDAY NIGHT...TAPERING OFF OVERNIGHT INTO TUESDAY.
OVERALL...LOOKING LIKE A LIGHT QPF EVENT...PROBABLY STAYING BELOW
0.20" LE. THUS IN ALL LIKELIHOOD...IT WONT BE A BIG SNOW EVENT...BUT
POTENTIAL EXISTS FOR A COUPLE INCHES FOR AT LEAST A PORTION OF
CWA...WITH RATIOS SLIGHTLY ABOVE 10:1. HAVE LINGERING SLIGHT POPS ON
TUESDAY DUE TO UPPER TROUGH AXIS STAYING NEARBY...WITH TEMPERATURES
MODERATING A BIT MORE.
WEDNESDAY THROUGH FRIDAY...
POLAR VORTEX FULLY RETREATS INTO NORTHERN
CANADA...BRINGING US BACK TO A ZONAL...PACIFIC DOMINATED JET STREAM
PATTERN...ALLOWING TEMPERATURES TO WARM BACK ABOVE NORMAL LEVELS.
WARMING COULD BE LIMITED BY LINGERING SNOW COVER...BUT 40S ARE
CERTAINLY POSSIBLE DURING THE PERIOD...WITH H85 TEMPS WARMING TO AT
OR ABOVE 0C. AS MENTIONED...HOWEVER...LARGE MODEL DIFFERENCES AND
UNCERTAINTY ON MIDLEVEL AND SURFACE FEATURES...WITH ECMWF BRINGING
MIDLEVEL LOW AND SURFACE REFLECTION ACROSS AREA WEDNESDAY INTO
THURSDAY...WHILE GFS HAS A DRY LOOK TO IT. HAVE SLIGHT TO LOW END
CHANCE POPS FROM ALL BLEND DURING THIS PERIOD AND A RAIN OR SNOW
MENTION DUE TO MARGINAL AT BEST THERMAL PROFILE.
RC
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 03Z...
* NORTH-NORTHWEST WINDS GUSTING TO 25-30 KT THROUGH THE EVENING
THEN EASING TO AROUND 25 KT OVERNIGHT.
* STRONG LAKE EFFECT SNOW BAND REMAINING JUST OFF SHORE OF
ILLINOIS THROUGH THE EVENING THEN SHIFTING EASTWARD OVERNIGHT.
MDB
//DISCUSSION...UPDATED 03Z...
LAKE EFFECT SNOW BAND BECOMING BETTER ORGANIZED AND MORE INTENSE.
BAND EXPECTED TO WOBBLE BACK AND FORTH FROM EAST TO WEST FOR A FEW
HOURS BEFORE MAKING A STEADIER MOVE TO THE EAST. LATEST RADAR
TRENDS SUPPORT GYY SEEING A PERIOD OF HEAVIER SNOW FOR PERHAPS A
FEW HOURS WITH VERY INTENSE SNOWFALL RATES. THE BULK OF THE BAND
WILL LIKELY REMAIN JUST TO THE EAST. ONCE THE HEAVIEST SNOW EXITS
LATER THIS EVENING SNOW SHOWERS WILL PROBABLY CONTINUE BUT VSBY
WILL LIKELY BE IMPROVED TO A FEW MILES...BUT ADDITIONAL BURSTS OF
SNOW MAY REMAIN POSSIBLE A FEW HOURS BEYOND MIDNIGHT. STRONG
NORTH-NORTHWEST WINDS WILL CONTINUE TO GUST TO AROUND 35 KT WITH
PERIODIC GUSTS CLOSER TO 40 KT NOT OUT OF THE QUESTION. THIS WILL
YIELD BLOWING SNOW AND REDUCED VSBY EVEN IF FALLING SNOW IS LESS
INTENSE.
ELSEWHERE...SKIES ARE QUICKLY CLEARING ACROSS NORTHERN ILLINOIS
WITH MAINLY SKC EXPECTED ACROSS THE WESTERN CHI METRO AND POINTS
WEST WITH SOME LOWER END VFR CLOUDS LINGERING CLOSER TO THE
LAKESHORE/ORD/MDW THROUGH THE EVENING. NORTH-NORTHWEST WINDS WILL
CONTINUE TO GUST IN THE 25-30 KT RANGE ACROSS THE CHI METRO
TERMINALS WITH LESSER GUSTS TO THE WEST.
FROM 00Z...
LAST OF THE LARGE SCALE SNOW IS MOVING SOUTHEAST ACROSS
ORD/MDW AT 00Z WHILE LAKE EFFECT BAND CONTINUES TO IMPACT GYY AND
VICINITY. SOME LIGHT SNOW SHOWERS OR FLURRIES MAY TRAIL THE MAIN
AREA OF SNOW AT RFD/DPA/ORD INTO MID EVENING. MDW IS A BIT TOUGHER
WITH THE BULK OF THE SNOW EXITING OVER THE NEXT HOUR OR SO BUT
WITH THE PROXIMITY OF THE FLOW FROM THE LAKE ADDITIONAL SNOW
SHOWERS MAY CONTINUE THROUGH MID EVENING. WILL CONTINUE WITH LIGHT
SNOW AND SOME REDUCED VSBY THERE FOR NOW.
GYY...THE LAKE BAND IS EXPECTED TO BECOME BETTER ORGANIZED INTO
MID EVENING LIKELY CONTINUING TO AFFECT GYY INTO THE OVERNIGHT
BEFORE SHIFTING EAST. STRONG NORTH WINDS GUSTING IN THE 35-45 KT
RANGE WILL CONTINUE AT GYY LEADING TO SIGNIFICANT BLOWING AND
DRIFTING SNOW. EXTREME SNOWFALL RATES OF 1-3 INCHES PER HOUR ARE
EXPECTED WITH THE SNOW BAND ONCE IT BECOMES BETTER ORGANIZED THIS
EVENING. THE MAIN CHALLENGE WILL BE TRACKING HOW LONG THE BAND
WILL AFFECT THE TERMINAL WHICH AT THIS POINT LOOKS TO BE THROUGH
MOST OF THE EVENING AND POSSIBLY INTO THE EARLY OVERNIGHT HOURS.
ONCE THE BAND MOVES OFF TO THE EAST SNOW WILL QUICKLY LET UP BUT
BLOWING SNOW WILL LIKELY CONTINUE RESULTING IN CONTINUED REDUCED
VISIBILITY.
THE ILLINOIS TERMINALS WILL LIKELY SCATTER OUT OVERNIGHT BUT SPECIFIC
TIMING IS A BIT UNCERTAIN. NORTH-NORTHWEST WINDS WILL TURN MORE
NORTHWEST SATURDAY MORNING BUT REMAIN GUSTY INTO THE 20-25 KT
THROUGH MUCH OF THE DAY. VFR CONDITIONS ARE EXPECTED FOR SATURDAY
WITH LOWER END VFR CIGS POSSIBLY IN THE MORNING BUT CLEARING FOR
THE AFTERNOON.
MDB
//ORD AND MDW CONFIDENCE...UPDATED 03Z...
* HIGH CONFIDENCE IN WIND FORECAST.
MDB
//OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z...
SUNDAY...VFR.
MONDAY/TUESDAY...LIGHT SNOW LIKELY WITH IFR POSSIBLE.
WEDNESDAY...VFR.
THURSDAY...CHANCE OF RAIN AND SNOW.
MDB
&&
.MARINE...
156 PM CST
THE MAIN CONCERNS CONTINUE TO FOCUS ON THE STRONG WINDS ACROSS LAKE
MICHIGAN TONIGHT INTO SATURDAY. THE STRONG SURFACE COLD FRONT IS
MOVING ACROSS THE SOUTHERN TIP OF LAKE MICHIGAN EARLY THIS
AFTERNOON. I EXPECT NORTHERLY GALE FORCE WINDS AROUND 35 KNOTS IN
THE WAKE OF THIS FRONT. AS VERY COLD AIR CONTINUES TO SPILL OVER THE
LAKE THIS EVENING...A FAVORABLE THERMODYNAMIC SETUP WILL OCCUR FOR A
BANDS OF INTENSE LAKE EFFECT SNOW TO DEVELOP. THERE IS ALSO A GOOD
POSSIBILITY THAT AS SOME AREAS ACROSS THE SOUTHERN END OF THE LAKE
MAY SEE GALES INCREASE TO 40 KT FOR A PERIOD TONIGHT AS THESE
CONVERGENT BANDS OF SNOW DEVELOP. THESE STRONG WINDS WILL LIKELY
ALSO AFFECT THE INDIANA NEAR SHORE WATERS.
WINDS WILL ABATE SOME ON SATURDAY. HOWEVER...THE PRESSURE GRADIENT
WILL REMAIN FAIRLY TIGHT ACROSS THE LAKE AS HIGH PRESSURE DROPS OUT
OF SOUTHERN CANADA AND BUILDS ACROSS THE LOWER AND MIDDLE MISSOURI
RIVER VALLEY. THEREFORE...EXPECT NORTHWEST WINDS TO 30 KT TO
CONTINUE ON SATURDAY AND SATURDAY NIGHT. THIS SURFACE HIGH WILL
BUILD EASTWARD ACROSS THE OHIO VALLEY ON SUNDAY AND SUNDAY NIGHT.
ONCE THIS OCCURS THE WINDS WILL BECOME WEST SOUTHWESTERLY BY MONDAY.
WIND SPEEDS WILL DIMINISH INTO MONDAY.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...LAKE EFFECT SNOW WARNING...INZ001 UNTIL 4 AM SATURDAY.
LAKE EFFECT SNOW WARNING...INZ002-INZ011 UNTIL 9 AM SATURDAY.
LM...GALE WARNING...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-
LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 AM
SATURDAY.
GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565 UNTIL 6
AM SATURDAY.
GALE WARNING...ILLINOIS NEARSHORE WATERS UNTIL 4 AM SATURDAY.
SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742...4 AM SATURDAY TO 6
AM SUNDAY.
GALE WARNING...INDIANA NEARSHORE WATERS UNTIL 10 AM SATURDAY.
SMALL CRAFT ADVISORY...LMZ743-LMZ744-LMZ745...10 AM SATURDAY TO
2 PM SUNDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
423 AM EST SAT FEB 11 2012
.SHORT TERM.../TODAY THROUGH SUNDAY NIGHT/
...LAKE EFFECT SNOW EVENT UNDERWAY...
ARCTIC COLD FRONT HAS SWEPT ACROSS THE FORECAST AREA WITH
TEMPERATURES IN THE TEENS AND DEWPTS FALLING INTO THE SINGLE DIGITS.
SOME LEFTOVER LIGHT SNOW WAS SEEN ON OBS AND RADAR ACROSS PORTIONS
OF NORTHEASTERN INDIANA AND NORTHWESTERN OHIO. MAIN FOCUS WAS WELL
DEFINED INTENSE LAKE EFFECT SNOW BAND THAT RAPIDLY DEVELOPED ACROSS
LAKE AND PORTER COUNTIES THIS PAST EVENING AND AFTER A BRIEF SHIFT
WEST AND INCREASE IN EASTERN PROGRESS HAS BEEN NOTED WITH THE BAND
CURRENTLY SITUATED ACROSS LAPORTE AND STARKE COUNTIES AHEAD OF
SCHEDULE. REPORT FROM VALPO UNIV OF LIGHTNING WAS RECEIVED AS THE
HEAVIEST PART OF THE BAND SHIFTED ACROSS THAT AREA. RADAR TRENDS
ACROSS THE FORECAST AREA HAS SHOWN A DOWNWARD TREND IN SOUTHERN
EXTENT AND INTENSITY OF THE BAND. UPSTREAM ACROSS THE LAKE KGRR
RADAR SHOWING AN INCREASE IN RETURNS AS THE BAND SHIFTED MORE ALONG
THE EASTERN SHORE OF THE LAKE. A FEW RUNS OF THE HRRR SUGGESTED THIS
MAY OCCUR WITH THE INITIAL BAND WEAKENING WITH TIME AS CONVERGENCE
WEAKENED AND MORE OF A MULTI BAND SETUP BEGAN TO ESTABLISH WITH TIME
THIS MORNING. WHILE FULL WARNING CRITERIA MAY NOT BE
MET...DETERIORATING CONDITIONS STILL WARRANT HOLDING ONTO CURRENT
HEADLINES. RISK FOR WARNING CRITERIA STILL POSSIBLE OVER BERRIEN
COUNTY AS BAND REORIENTS AND PERSISTS INTO EARLY AFTERNOON. DID
EXPAND POPS FURTHER SOUTH AND EAST AS INLAND EXTENT OF BANDS MAY
INCREASE AS OVERALL FLOW INCREASES SOMEWHAT WITH STRONGER GRADIENT
SHIFTING ACROSS THE AREA. WOULD NOT EXPECT MUCH IMPACT BUT FELT AT
LEAST CHC POPS WERE NEEDED DOWNSTREAM OF THE BAND.
GIVEN UNCERTAINTY OF EXTENT AND INTENSITY OF HEAVIEST BANDS HAVE
WENT WITH LIKELY POPS INTO THE AFTERNOON WITH ONLY LIGHT ADDITIONAL
ACCUMS.
NW FLOW WILL PERSIST ACROSS THE REGION INTO SUNDAY. HOWEVER...LL
TEMPS WILL QUICKLY UNDERGO MODERATION TONIGHT INTO SUNDAY CAUSING
DELTA T`S TO DECREASE AND INVERSION HGTS TO LOWER. THE RESULT WILL
BE SOME LINGERING VERY LIGHT SNOW OR FLURRIES INTO TONIGHT BEFORE
ENDING. SUNDAY/SUNDAY NIGHT APPEAR DRY AT THIS POINT WITH HIGH
PRESSURE BUILDING IN. MEAN RH VALUES DROPS CONSIDERABLY BY SUNDAY
AFTERNOON INTO SUNDAY NIGHT...ALLOWING FOR MOSTLY CLEAR TO CLEAR
SKIES AND MODERATING TEMPS.
&&
.LONG TERM...MONDAY THROUGH FRIDAY
OVERALL VERY FEW CHANGES REQUIRED TO THE LONG TERM PERIOD FOR THIS
FORECAST CYCLE.
FOR MONDAY...LOW LEVEL ANTICYCLONE WILL SHIFT EASTWARD THROUGH THE
LOWER MS RIVER VALLEY INTO THE SOUTHEAST US...EVENTUALLY ALLOWING
LOW LEVEL RETURN SOUTHWESTERLY FLOW TO SETUP. A SHEARED UPPER VORT
MAX DIVORCED FROM STRONGER STEERING FLOW AS A RESULT OF WESTERN
CONUS SPLIT FLOW SHOULD GRADUALLY GET PHASED WITH A MORE AMPLIFIED
SOUTHERN STREAM TROUGH KICKING OUT OF THE FOUR CORNERS REGION. AS
THIS OCCURS...STRONGER LOW LEVEL THETAE ADVECTION/ISENTROPIC LIFT
SHOULD BE FOCUSED JUST WEST OF THE AREA. NAM/GFS ISENTROPIC PROGS IN
290-280K LAYER DO INDICATE MORE SUBSTANTIAL LOWERING OF
CONDENSATIONAL PRESSURE DEFICITS THROUGHOUT THIS LAYER BY LATE IN
THE DAY MONDAY...BUT SUBCLOUD LAYER MAY BE TOO DRY FOR MOST AREAS TO
RECEIVE ANY PRECIP MONDAY AFTERNOON. A SHARP LOW LEVEL GRADIENT
NOTED IN MIXING RATIOS THROUGHOUT THIS LAYER FROM WEST TO EAST ON
MONDAY...AND PREVIOUS POP GRADIENT MONDAY AFTERNOON FROM LOW CHANCE
WEST TO SLIGHT CHANCE EAST STILL APPEARS REASONABLE. STRONGER
ISENTROPIC UPGLIDE AND MID LEVEL FORCING TO MOVE IN FOR MONDAY NIGHT
WHICH STILL APPEARS TO BE SHAPING UP AS A HIGH POP/LOW QPF EVENT
BASED ON A RELATIVELY SHORT DURATION OF BETTER LOW/MID LEVEL
MOISTURE PROFILES AND RATHER DISJOINTED NATURE OF MID/UPPER LEVEL
FORCING WITH ONLY PARTIAL PHASING OF THESE AFOREMENTIONED SHORT
WAVES. MOST OF PRECIP EXPECTED MONDAY NIGHT BUT WILL CONTINUE TO
CARRY CHANCE -SN MENTION INTO TUESDAY WITH LAGGING SHORT WAVE SLOW
TO EXIT THE AREA. PRECIP MAY END AS A PERIOD OF DRIZZLE/FLURRIES
TUESDAY NIGHT...ESPECIALLY ACROSS EASTERN AREAS...AS MOISTURE
PROFILES BECOMING INCREASING SHALLOW WITH ONLY WEAK MID LEVEL
FORCING.
MEDIUM RANGE MODELS HAVE STARTED TO CONVERGE A BIT MORE IN REGARDS
TO MID/LATE WEEK SYSTEM WITH ECMWF EXHIBITING SOME BETTER RUN TO RUN
CONTINUITY IN COMPARISON TO 24 HOURS AGO. FLOW PATTERN QUITE COMPLEX
FOR THIS PERIOD WITH MAIN QUESTION REGARDING PHASING ISSUES OF NEXT
SOUTHERN STEAM UPPER TROUGH WITH ACTIVE SOUTHERN CANADIAN NORTHERN
STREAM. GENERALLY FOLLOWED HPC PREFERENCE OF A SLIGHTLY SLOWER THAN
ECMWF SOLUTION GIVEN EXPECTED FAST BIASED EJECTION OF SOUTHWEST US
WAVE. THIS CENTERS HIGHEST POPS IN THE THURS NIGHT PERIOD BUT
DEPENDING ON RATE OF EJECTION OF THIS TROUGH...PRECIP MAY EVENTUALLY
HAVE TO BE ADDED INTO FRIDAY. HARD TO DEVIATE AT THIS TIME FROM A
BROADBRUSH RAIN/SNOW PTYPE MENTION FOR THURSDAY/THURSDAY NIGHT GIVEN
EXPECTED MARGINAL LOW LEVEL THERMAL PROFILES DURING THIS PERIOD.
TEMPS SHOULD TREND SLIGHTLY ABOVE SEASONABLE NORMS FOR THE WED-FRI
PERIOD WITH SOME SUGGESTIONS OF A BRIEF SHOT OF COLD ADVECTION
TOWARD THE END OF THE PERIOD AS LARGER SCALE NORTHERN STREAM TROUGH
DIGS ACROSS THE GREAT LAKES REGION.
&&
.AVIATION...
06Z TAFS.
SYNOPTIC SNOW SHOULD BEGIN TO MOVE OUT OF KFWA OVER THE NEXT FEW
HOURS WITH ATTENTION TURNING TO INTENSE LAKE EFFECT SNOW BAND
CURRENTLY ACROSS NORTHWEST INDIANA. LOW LEVEL WINDS SHOULD
CONTINUE TO BACK THROUGH THE OVERNIGHT HOURS ALLOWING THIS BAND TO
EVENTUALLY SHIFT EASTWARD AND AFFECT KSBN BY THE 11Z-13Z
TIME FRAME. HAVE MAINTAINED IDEA FROM PREVIOUS TAFS WITH A PERIOD
OF LIFR CONDITIONS IN ASSOCIATION WITH THIS BAND GIVEN MODERATE TO
STRONG LAKE INDUCED INSTABILITY AND A MORE FAVORABLE NORTH
NORTHWEST FETCH FOR KSBN. IT APPEARS AS THOUGH THERE WILL BE A
THREE HOUR WINDOW OF INTENSE SNOWFALL RATES OF POTENTIALLY 1 TO 2
INCHES PER HOUR AT KSBN IN THE 12Z TO 16Z TIME FRAME. BLOWING SNOW
ALSO LIKELY TO CAUSE SOME CONTINUED VSBY RESTRICTIONS THROUGH THE
LATE MORNING HOURS. INVERSION HEIGHTS WILL BEGIN TO LOWER BY LATE
MORNING WITH STRONGER LAKE EFFECT SNOW SHOWERS SHIFTING NORTH AND
EAST OF KSBN LATE MORNING. DESPITE LOWERING INVERSION
HEIGHTS...DID KEEP SCT SNOW SHOWERS AND FLURRIES THROUGH THIS
FORECAST VALID PERIOD ALONG WITH MVFR CIGS.
&&
.MARINE...
WILL CONTINUE GALE WARNINGS THROUGH THE MORNING. SUSTAINED WINDS
IN THE 35 TO 40 KT RANGE HAVE PERSISTED FOR SEVERAL HOURS AT
MICHIGAN CITY WITH GUSTS OF 40 TO 44 KTS. WINDS MUCH LIGHTER AT ST
JOE/BENTON HARBOR BUT EXPECT THEM TO INCREASE AS STRONG GRADIENT
SHIFTS OVER HEAD THIS MORNING.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...WINTER STORM WARNING UNTIL 10 AM CST THIS MORNING FOR INZ003-012.
WINTER WEATHER ADVISORY UNTIL 11 AM EST THIS MORNING FOR INZ013.
WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS EVENING FOR INZ004-
014.
MI...WINTER STORM WARNING UNTIL 6 PM EST THIS EVENING FOR MIZ077.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 7 PM EST SUNDAY FOR LMZ043-046.
GALE WARNING UNTIL 5 AM EST EARLY THIS MORNING FOR LMZ043-046.
&&
$$
SHORT TERM...FISHER
LONG TERM...MARSILI
AVIATION...MARSILI
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
109 AM EST SAT FEB 11 2012
.AVIATION...
06Z TAFS.
SYNOPTIC SNOW SHOULD BEGIN TO MOVE OUT OF KFWA OVER THE NEXT FEW
HOURS WITH ATTENTION TURNING TO INTENSE LAKE EFFECT SNOW BAND
CURRENTLY ACROSS NORTHWEST INDIANA. LOW LEVEL WINDS SHOULD
CONTINUE TO BACK THROUGH THE OVERNIGHT HOURS ALLOWING THIS BAND TO
EVENTUALLY SHIFT EASTWARD AND AFFECT KSBN BY THE 11Z-13Z
TIME FRAME. HAVE MAINTAINED IDEA FROM PREVIOUS TAFS WITH A PERIOD
OF LIFR CONDITIONS IN ASSOCIATION WITH THIS BAND GIVEN MODERATE TO
STRONG LAKE INDUCED INSTABILITY AND A MORE FAVORABLE NORTH
NORTHWEST FETCH FOR KSBN. IT APPEARS AS THOUGH THERE WILL BE A
THREE HOUR WINDOW OF INTENSE SNOWFALL RATES OF POTENTIALLY 1 TO 2
INCHES PER HOUR AT KSBN IN THE 12Z TO 16Z TIME FRAME. BLOWING SNOW
ALSO LIKELY TO CAUSE SOME CONTINUED VSBY RESTRICTIONS THROUGH THE
LATE MORNING HOURS. INVERSION HEIGHTS WILL BEGIN TO LOWER BY LATE
MORNING WITH STRONGER LAKE EFFECT SNOW SHOWERS SHIFTING NORTH AND
EAST OF KSBN LATE MORNING. DESPITE LOWERING INVERSION
HEIGHTS...DID KEEP SCT SNOW SHOWERS AND FLURRIES THROUGH THIS
FORECAST VALID PERIOD ALONG WITH MVFR CIGS.
&&
.UPDATE...
UPDATED ZONES JUST SENT TO REMOVE ALL WINTER WEATHER HEADLINES
EXCEPT FAR NW/W COUNTIES WHERE LAKE EFFECT CONCERNS WILL INCREASE
IN THE COMING HOURS.
LARGE SCALE SYNOPTIC FORCING HAS WOUND DOWN RAPIDLY OVER THE PAST
COUPLE OF HOURS. FLURRIES OR AREAS OF LIGHT SNOW WILL STILL BE
SEEN EAST OF US 131 THROUGH THE REMAINDER OF THE NIGHT. EVEN
THOUGH SOME BLOWING AND DRIFTING WILL TAKE PLACE...OVERALL THREAT
HAD DIMINISHED SO WILL GET RID OF HEADLINES.
FOCUS WILL THEN SHIFT TO SINGLE LAKE EFFECT BAND THAT HAS DROPPED
UPWARDS OF 6 TO 10 INCHES OF SNOW ACROSS PORTIONS OF PORTER
COUNTY. SECONDARY COLD FRONT DROPPED THROUGH THE AREA CAUSING A
BRIEF SHIFT WESTWARD IN THE BAND AND SLIGHT DECREASE IN INTENSITY.
WITH THE FRONT HAVING CLEARED THAT AREA...BAND WAS RAPIDLY GAINING
STRENGTH ONCE AGAIN...BUT WAS ALSO BEGINNING TO TRANSITION EAST A
BIT FASTER THAN PREVIOUSLY FORECAST. BY 130 AM EST/1230 AM CST/
BAND WILL LIKELY BE IN OR CLOSE TO WESTERN PORTIONS OF LA PORTE
AND STARKE COUNTIES WHERE 1 TO 2 INCHES PER HOURS AND NEAR
WHITEOUT CONDITIONS MAY BE SEEN FOR SEVERAL HOURS. HRRR RUNS DO
PROGRESS THE BAND SLOWY EASTWARD...POSSIBLY REACHING THE SOUTH
BEND AREAS IN THE 9 TO 12Z WINDOW. FOR NOW WILL LEAVE LAKE EFFECT
RELATED HEADLINES IN PLACE AND RE-EVALUATE IN A FEW HOURS WITH
NORMAL PACKAGE ISSUANCE.
.PREV DISCUSSION... /ISSUED 424 PM EST FRI FEB 10 2012/
SHORT TERM...
TONIGHT THROUGH SATURDAY NIGHT. MAJOR CHGS WRT WDSPRD SYNOPTIC SNWFL
FOLLOWED BY SIG LES EVENT...THOUGH ALL IN ALL IN STEP WITH TRENDS
SEEN THROUGH PAST 36 HRS. SIG EWD PLACEMENT OF MAJOR AXIS BAND NOTE
IN NMM/ARW/NAM AND HAVE BUY IN GIVEN NEAR TERM DVLPMNTS WRT
SWRN/WCNTL MICHIGAN SFC RESPONSE SEEN ERLIER TODAY. A DEEPER MORE
STACKED SYSTEM GOING INTO SAT MORNING ACRS LWR GRTLKS TO PROVIDE FOR
MORE WELL DVLPD MAJOR AXIS BAND AND FURTHERMORE KEEPS DRY AIR ACRS
WI IN PLACE AND NOT ALLOW NEAR AS MUCH ENTRAINMENT INTO BAND AS WAS
FEARED YDAY AND ERLIER TDY. FURTHERMORE LESSER SHEARED AND MORE
CYCLONIC UPSTREAM LAKE SUPR/NRN LAKE MICHIGAN SHOULD AID IN FORMING
MORE RESOLUTE BAND. NEARNESS OF EVENT COMBINED WITH INCRSD INTENSITY
OF PRESENT SYNOPTIC EVENT UNDERWAY NECESSITATES HOISTING OF
WARNINGS/ADVISORIES. FURTHER COMPLICATING MATTERS IS VERY BRIEF LULL
BETWN DWINDLING SYNOPTIC EVENT AND LES INTO NCNTL IN. TOO AVOID
MULTIPLE HEADLINES HAVE OPTED FOR MORE GENERAL WINTER WX
WARNING/ADVISORIES AND HOLD LONGER DURATION TO LES TARGETED
COUNTIES. BEST THERMAL INSTABILITY NOTED AROUND 12 UTC SAT WITH
LK/8H THERMAL DIFFERENTIALS NEARING 20C. ALSO OF NOTE IS SRN LAKE
MICHIGAN MODEL MUCAPE OF 150 J/KG COINCIDENT WITH LONG AXIS LLVL
CONVERGENCE. DEEPER MOISTURE INTO DGZ SUGGESTIVE OF LARGE AGGREGATED
FLAKES AND HAVE FINER DETAIL/HIGHER LIQUID TO SNOW RATIOS IN LES
AREAS DIFFERENTIATING DEPARTING SERN CWA SYNOPTIC EVENT THAT SHOULD
HAVE RATIOS CLOSER TO CLIMO. WIDE VARIABILITY OF SNOWFALL AMOUNTS
ANTICIPATED WITH HVST AMOUNTS ALONG/W OF 421 EXPECTED WHERE
GREATEST SNOWFALL RATE POTNL MAINTAINS LONGEST DURATION. THEREAFTER
BACKING CBL TO 330 DEGREES BY MIDDAY SAT AND 310 BY LATE AFTN WITH
LES BAND SWINGING NORTHEAST WHILST LAKE INDUCED EQL LOWERS FM 10KFT
TO NEAR 5KFT.
LONG TERM... / SUNDAY THROUGH FRIDAY /
UPPER LEVEL HEIGHTS WILL BE ON THE RISE SUNDAY...BRINGING ABOUT A
MODEST RESPONSE THERMALLY AS 925/850 MB TEMPS WARM AROUND 10 DEG C
FROM SATURDAY INTO SUNDAY. HOWEVER...HIGHS WILL LIKELY ONLY RECOVER
INTO THE UPPER 20S TO NEAR 30F GIVEN SHALLOW MIXING. ALSO...BRISK NW
WINDS WILL LIKELY PERSIST INTO SUNDAY AS A LOW LVL ANTICYCLONE
DRIFTS SEWD TOWARDS THE MID/LOWER MS VALLEY. THIS LOW LVL TRAJECTORY
SHOULD ALLOW LAKE CLOUDS TO LINGER FOR MUCH OF THE DAY ACROSS
NORTHERN PORTIONS OF THE FA AS BOUNDARY LAYER MOISTURE LOCKS IN
UNDER A STRENGTHENING SUBSIDENCE INVERSION.
QUASI-ZONAL SPLIT FLOW WILL TAKE HOLD ON THE LOWER 48 NEXT WEEK WITH
TEMPS MODERATING TO ABOVE NORMAL VALUES BY WEDNESDAY. A LIGHT SNOW
EVENT CONTINUES TO LOOK POSSIBLE LATE MONDAY INTO TUESDAY AS LOWER
AMPLITUDE SHORTWAVE ENERGY PROPAGATES INTO THE MIDWEST. HEIGHT FALLS
WITH THIS ENERGY WILL ELICIT ENOUGH OF A LOW LVL RESPONSE TO SUPPORT
INCREASING ISENTROPIC UPGLIDE AND THETA-E RISES MAINLY IN THE 9-7H
LAYER. MODEL QPF HAS REMAINED RELATIVELY CONSISTENT...GENERALLY BTW
A TENTH AND TWO TENTHS...HINTING AT A 0.5-2.0" TYPE EVENT. OPTED TO
REMAIN SOMEWHAT CONSERVATIVE WRT POPS DURING THIS TIME AS MID/UPPER
LVL SUPPORT APPEARS DISJOINTED GIVEN UNCERTAINTIES WRT
TIMING/INTERACTION BTW STREAMS.
LITTLE TO NO CHANGES TO THE FCST BEYOND WEDNESDAY AS MODELS CONTINUE
TO SHOW LITTLE RUN-TO-RUN CONSISTENCY. THIS IS EXPECTED IN A SPLIT
FLOW REGIME AS LARGE DIFFERENCES REMAIN WITH TIMING AND INTERACTION
OF STREAMS. SOME GUIDANCE INDICATES LESS RIDGING ACROSS THE SE CONUS
WITH MORE IN THE WAY OF MID LVL CONFLUENCE LOCALLY SUPPORTING DRY
CONDITIONS AND LOW LVL RIDGING. THE LATEST ECMWF AND 00Z/06Z GFS
SHOW GREATER AMPLIFICATION/SE RIDGING ALLOWING A STRONGER SOUTHERN
STREAM SHORTWAVE TO BRING HEAVIER PCPN NEWD INTO THE FA BY THURSDAY
OR FRIDAY. HARD TO PUT MORE STOCK ON EITHER SOLUTION GIVEN THE LACK
OF INTRA-RUN CONSISTENCY SEEN IN THE GFS AND ECMWF.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...WINTER STORM WARNING UNTIL 10 AM CST SATURDAY FOR INZ003-012.
WINTER WEATHER ADVISORY UNTIL 11 AM EST THIS MORNING FOR INZ013.
WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS EVENING FOR INZ004-
014.
MI...WINTER STORM WARNING UNTIL 6 PM EST THIS EVENING FOR MIZ077.
OH...NONE.
LM...SMALL CRAFT ADVISORY FROM 5 AM EARLY THIS MORNING TO 7 PM EST
SUNDAY FOR LMZ043-046.
GALE WARNING UNTIL 5 AM EST EARLY THIS MORNING FOR LMZ043-046.
&&
$$
SHORT TERM...MURPHY
LONG TERM...STEINWEDEL
AVIATION...MARSILI
UPDATE...FISHER
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1129 PM CST FRI FEB 10 2012
.AVIATION...
VFR CONDITIONS TO PREVAIL THROUGH TAF CYCLE. TIGHT PRESSURE GRADIENT
BETWEEN CANADIAN HIGH BUILDING THROUGH THE PLAINS AND LOW TO THE
EAST WILL CONTINUE GUSTY N/NW WINDS AT 10-20 KTS FOR MUCH OF THE PD.
&&
.PREV DISCUSSION... /ISSUED 305 PM CST FRI FEB 10 2012/
SYNOPSIS...
12Z UA ANALYSIS HAS A COLD FRONT FROM THE MACKINAC STRAITS INTO
NORTHERN KANSAS WITH TROFS FROM THE MID ATLANTIC BACK INTO THE
PLAINS. SATELLITE AND RADAR TRENDS THROUGH MID AFTERNOON SHOWS AREAS
OF LIGHT SNOW AND SNOW SHOWERS ACROSS THE WESTERN GREAT LAKES WITH
CLEARING SKIES IN MINNESOTA.
18Z SFC ANALYSIS HAS A LOW JUST EAST OF KMKG AND ANOTHER JUST
NORTHEAST OF KORD. THE ARCTIC FRONT RAN FROM THE SECOND LOW
SOUTHWEST INTO NORTHERN TEXAS. DEW POINTS WERE IN THE 20S AND 30S
AHEAD AND IMMEDIATELY BEHIND THE FRONT WITH SINGLE DIGITS ABOVE AND
BELOW ZERO ACROSS THE NORTHERN PLAINS.
SHORT TERM...TONIGHT AND SATURDAY...
RUC TRENDS USING THE 900-950MB AND 0.5-1.0KM RH LAYERS ARE DOING A
REASONABLY GOOD JOB OF DEPICTING THE CURRENT CLOUD COVER ACROSS THE
AREA. SNOW SHOWERS/FLURRIES WILL CONTINUE THROUGH THE AFTERNOON WITH
MOST SNOW SHOWERS DISSIPATING WITH SUNSET. STRONG CYCLONIC FLOW AND
VORT MAXES ROTATING THROUGH THE AREA SHOULD PROLONG THE FLURRIES
INTO THE EARLY EVENING OVER ROUGHLY THE EASTERN HALF OF THE CWFA.
GENERAL ACCUMULATIONS SHOULD RANGE FROM A TRACE TO A DUSTING.
A FEW HOURS AGO THE RUC WAS INDICATING CLEARING WOULD OCCUR FROM THE
NORTHWEST AFTER MID EVENING AND THEN TAKE MOST OF THE NIGHT TO CLEAR
OUT EAST OF THE MISSISSIPPI. HOWEVER...A NEW CLEAR AREA HAS
DEVELOPED IN AN AREA OF SUBSIDENCE ACROSS NORTHERN WISCONSIN. RUC
TRENDS USING THE 900-950MB AND 0.5-1.0KM RH LAYERS ARE NOW
SUGGESTING THE CWFA MAY SEE CLEARING STARTING FROM THE NORTHWEST AND
WEST AFTER MID-EVENING AND ALSO FROM THE NORTHEAST. IF THIS DOES
OCCUR THEN ROUGHLY THE SOUTHEAST QUADRANT OF THE CWFA WOULD BE THE
LAST TO CLEAR OUT AFTER MIDNIGHT.
TEMPERATURES WILL BE INTERESTING. AREAS THAT CLEAR OUT SOONER WILL
DROP QUICKLY DUE TO THE CAA THAT WILL CONTINUE OVERNIGHT. THE FACT
THAT WINDS WILL NOT DECOUPLE FROM THE BOUNDARY LAYER WILL BE WHAT
KEEPS LOWS ABOVE ZERO. FAVORED COLD AREAS IN THE WAPSI AND SAUK
VALLEYS MAY APPROACH ZERO IN SPITE OF THE WINDS. THE WIND AND
TEMPERATURES WILL DROP WIND CHILLS WELL BELOW ZERO BUT ARE EXPECTED
TO REMAIN JUST ABOVE ADVISORY CRITERIA.
SATURDAY WILL BE A COLD BRISK DAY. ARCTIC HIGH PRESSURE BUILDING
INTO THE AREA WILL RESULT IN SUNNY SKIES BUT WIND CHILLS ARE
EXPECTED TO REMAIN BELOW ZERO FOR MUCH OF THE MORNING. MAX
TEMPERATURES WILL STRUGGLE TO GET INTO THE UPPER TEENS AND LOWER 20S
BY MID AFTERNOON.
08..
LONG TERM...SATURDAY NIGHT THROUGH NEXT FRIDAY...
A HIGH PRESSURE RIDGE CENTERED OVER WESTERN IOWA SATURDAY EVENING
WILL MOVE EAST THROUGH THE MID MISSISSIPPI RIVER VALLEY BY MONDAY
MORNING. TEMPERATURES WILL BE THE MAIN CONCERN SATURDAY NIGHT AND
SUNDAY WITH THE RIDGE AXIS JUST WEST OF THE CWFA. THERE SHOULD BE
ENOUGH OF A PRESSURE GRADIENT TO KEEP WINDS FROM DECOUPLING. THE
WIND ALONG ALONG WITH BARE GROUND SHOULD KEEP MIN TEMPS SATURDAY
NIGHT ABOVE ZERO. ALTHOUGH A SMALL PART OF THE SOUTHWEST CWFA COULD
SLIP BELOW ZERO SINCE VISIBLE SATELLITE IMAGERY SHOWS SOME SNOW
COVER NOSING INTO THE AREA. TEMPS ARE EXPECTED TO REBOUND INTO THE
20S FOR SUNDAY.
PRECIPITATION CHANCES ENTER THE PICTURE SUNDAY NIGHT THROUGH TUESDAY
AS RETURN FLOW SETS UP BEHIND THE RETREATING LOW LEVEL RIDGE AND A
SHORT WAVE MOVES FROM THE NORTHERN PLAINS THROUGH THE MID AND UPPER
MISSISSIPPI VALLEY. THE GFS/NAM ARE THE MOST BULLISH ON PRECIP
DURING THIS PERIOD...GENERATING ABOUT 2 TO 3 TENTHS OF INCH WATER
EQUIVALENT WHILE THE ECMWF PRODUCES 1 TO 2 TENTHS. TEMPERATURES
WILL BE COLD ENOUGH THROUGH THE EVENT FOR ALL SNOW. KEPT AMOUNTS
IN THE 1 TO 3 INCH RANGE WITH THE HIGHEST AMOUNTS WEST AND NORTH.
IF THE GFS VERIFIES THEN THE 3 INCH AMOUNTS SHOULD BE REALIZED WHILE
THE ECMWF WOULD SUPPORT AMOUNTS CLOSER TO AN INCH. THE MEASURABLE
SNOW SHOULD END MONDAY EVENING WITH SOME FLURRIES LINGERING INTO
TUESDAY...SPECIALLY EAST OF THE MISSISSIPPI RIVER.
MODELS CONTINUE TO SHOW A SPLIT FLOW REGIME THROUGH THE REST OF THE
FORECAST PERIOD WITH TEMPERATURES RETURNING TO NEAR OR JUST ABOVE
NORMAL. MOST OF THE SOLUTIONS MOVE A NORTHERN STREAM TROF THROUGH
THE REGION THURSDAY OR FRIDAY BUT KEEP THE SYSTEM UN-PHASED AND
MOISTURE STARVED. THE LONE EXCEPTION IS THE 12Z ECMWF WHICH PHASES
THE TROF WITH THE SOUTHERN STREAM...RESULTING IN A MODERATE PRECIP
EVENT FOR THE REGION. AT THIS POINT THERE IS LOW CONFIDENCE IN THE
EXTENDED PROGS SO KEPT SOME SLIGHT CHANCE POPS IN FOR ALL OR PART OF
THE AREA WEDNESDAY THROUGH FRIDAY. ..DLF..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
942 PM MST FRI FEB 10 2012
.UPDATE...
600 PM MST FRI FEB 10 2012
STARTING GET A NICE NW-SE NARROW BAND OF SNOW FROM YUMA COUNTY
THROUGH SAINT FRANCIS TOWARD COLBY IN GOOD 700 FRONTOGENESIS FROM
GFS AND MID TO RIGHT REAR PORTION OF UPPER JET. YUMA WEB-CAM
SHOWING ROADS COVERED WITH PROBABLY AN INCH OR SO ALREADY ON THE
GROUND.
HAVE BUMPED UP SNOWFALL AMOUNTS SLIGHTLY...ESPECIALLY THROUGH 06Z
GIVEN RADAR AND MODEL TRENDS. ALSO BUMPED UP POPS INTO THE LIKELY
TO CATEGORICAL RANGE WHERE CONFIDENCE HIGHEST THAT THE CURRENT
BAND OF SNOW IS AND IS EXPECTED TO BE THROUGH EARLY TONIGHT. AS
DRIER AIR MOVES IN FROM THE NORTH BETTER CHANCES OF SNOW WILL
SHIFT SOUTHWEST OF CURRENT POSITION.
WILL AWAIT 00Z DATA BEFORE ADDRESSING TEMPS AND WINDS BUT I DID
TWEAK DEWPOINTS DOWN BASED ON CURRENT OBS WHICH ARENT TOO FAR OFF
FROM MET/MAV GUIDANCE.
007
&&
.SYNOPSIS...
ISSUED AT 222 PM MST FRI FEB 10 2012
EARLY AFTERNOON WV IMAGERY AND RUC H5 ANALYSIS SHOW LARGE SCALE
TROUGH ACROSS SOUTHERN CANADA EXTENDING SOUTH ACROSS THE GREAT
LAKES AND NORTHERN PLAINS. AT THE SURFACE THE COLD FRONT THAT
PASSED THROUGH THE CWA THIS MORNING HAS STALLED ALONG THE W/SW
PART OF THE CWA.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 222 PM MST FRI FEB 10 2012
TONIGHT THROUGH EARLY SATURDAY...A FRONTAL BOUNDARY WILL REMAIN
NEARLY STATIONARY ACROSS THE HIGHER TERRAIN OF THE CENTRAL HIGH
PLAINS. EXPECT AREAS OF LIGHT SNOW TO DEVELOP OVERNIGHT IN THE
VICINITY OF THIS BOUNDARY AS WEAK WAVES MOVE THROUGH THE NORTHWEST
FLOW ALOFT. THERE IS A SLIGHT CHANCE OF SOME FREEZING FOG IN VERY
CLOSE PROXIMITY TO THE FRONT OVERNIGHT OVER FAR EASTERN COLORADO
WHERE THE LOW CLOUDS WILL INTERSECT THE TERRAIN. HAVE TRIMMED THE
AREAS OF FREEZING FOG DOWN SOME...BUT HAVE KEPT IT IN THERE. THE
AIRMASS BEGINS DRYING OUT OVERNIGHT AS THE COLD AIR CONTINUES TO
PUSH FURTHER INTO THE REGION...SO HAVE DECREASED PRECIPITATION AND
CLOUD COVER FROM NORTHEAST TO SOUTHWEST OVERNIGHT THROUGH EARLY
SATURDAY MORNING.
LOCKHART
SATURDAY THROUGH SATURDAY NIGHT...WITH BAROCLINIC ZONE AND
LINGERING H85-H7 FRONTOGENSIS ACROSS THE WESTERN CWA...CANT RULE
OUT CONTINUED LIGHT SNOW THROUGH MID AFTERNOON SATURDAY. AIRMASS
CONTINUES TO DRY OUT THROUGH MIDDAY FROM THE NORTHEAST...SO I HAVE
KEPT CHANCE MENTION LIMITED TO FAR WESTERN CWA THROUGH 21Z. WITH
LINGERING CLOUD COVER AND VERY COLD AIRMASS IN PLACE TEMPERATURES
WILL STRUGGLE TO WARM MUCH. CURRENT FORECAST ALLOWS FOR SOME
DIURNAL WARMING WITH TEMPS IN THE MID TEENS TO LOW 20S ACROSS MUCH
OF THE CWA...AND AROUND 12 NEAR MCCOOK. CONSIDERING THE COLD
AIRMASS ALOFT AND LINGERING LOW CLOUDS...THIS MAY BE TOO
OPTIMISTIC. MODEL SOUNDINGS STILL SHOWING WARM LAYER ABOVE H85
ACROSS THE WESTERN PARTS OF THE CWA SATURDAY NIGHT...WITH SHALLOW
COLD NEAR SATURATED LAYER BELOW THIS. WITH UPSLOPE STILL
PERSISTING ALONG BAROCLINIC ZONE IN EASTERN COLORADO CANT RULE
OUT FREEZING FOG OR FREEZING DRIZZLE THROUGH EARLY SUNDAY MORNING.
I SAW NO NEED TO MAKE ANY MAJOR CHANGES TO PREVIOUS FORECAST WHICH
ALREADY HAD AREAS OF FREEZING FOG/DRIZZLE SATURDAY NIGHT THROUGH
EARLY SUNDAY MORNING.
DR
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 222 PM MST FRI FEB 10 2012
SUNDAY THROUGH MONDAY...SHORTWAVE RIDGING SHOULD KEEP CONDITIONS
DRY DURING THE DAY SUNDAY...WITH TEMPERATURES MODERATING ALOFT
FROM THE WEST. LINGERING CLOUD COVER WILL STILL LIMIT THE AMOUNT
OF DIURNAL WARMING AT THE SURFACE...SO TEMPS WILL LIKELY STILL
REMAIN BELOW FREEZING IN THE E/NE HALF OF THE CWA. A SHORTWAVE
TROUGH WILL MOVE IN THE REGION BY SUNDAY NIGHT. THIS SYSTEM DOES
NOT APPEAR TO BE VERY WELL ORGANIZED WITH MAIN H25-H3 JET OVER
OKLAHOMA PANHANDLE. THERE STILL APPEARS TO BE ENOUGH LIFT/MOISTURE
THAT I CANT RULE OUT SNOW SUNDAY NIGHT THROUGH MONDAY MORNING. BY
MONDAY AFTERNOON SHORTWAVE RIDGING BUILDS BACK OVER CWA.
TUESDAY THROUGH FRIDAY...SPLIT FLOW DOMINATES THE PATTERN
THROUGH THE REMAINING EXTENDED PERIODS. WHILE GUIDANCE IN MODERATE
AGREEMENT ON THE OVERALL PATTER...THERE IS VERY POOR RUN TO RUN
CONSISTENCY IN REGARDS TO THE HANDLING OF SMALLER SCALE FEATURES.
BEST CHANCE FOR PRECIP STILL APPEARS TO BE TUESDAY NIGHT THROUGH
WEDNESDAY NIGHT AS A SERIES OF SHORTWAVE TROUGHS MOVE THROUGH THE
PLAINS. POSITION/TIMING OF THESE FEATURES HAS BEEN ALL OVER THE
PLACE THE LAST FEW DAYS. THE 00Z ECMWF AND 00Z/12 GFS WERE
STARTING TO SHOW SIMILAR TRENDS FOR PRECIP OVER OUR CWA...WITH
LIGHT SNOW PREDOMINATELY OVER THE SOUTHERN HALF OF THE CWA QUICKLY
EXITING THE REGION BY TUESDAY AFTERNOON/WEDNESDAY NIGHT. THE 12Z
ECMWF AND GEM ARE BOTH MUCH MORE BULLISH WITH THIS SYSTEM
PRODUCING A CLOSED H5 CENTER AND MUCH MORE PRECIPITATION...WITH
THE 12Z ECMWF FURTHER NORTH AND LINGERS PRECIP THROUGH THURSDAY.
THIS IS SIGNIFICANT DEVIATION FROM PREVIOUS RUN AND ENSEMBLE DATA.
CONFIDENCE IS PRETTY LOW RIGHT NOW IN ANY PARTICULAR SOLUTION AT
THIS POINT CONSIDERING THE CHAOTIC NATURE OF THIS TYPE OF PATTER.
I KEPT THE FORECAST ON THE CONSERVATIVE END OF THE MODEL
SPREAD...WITH SLIGHT CHANCE POPS TUESDAY NIGHT THROUGH WEDNESDAY
NIGHT. TEMPERATURES THROUGH THIS PERIOD SHOULD REMAIN SLIGHTLY
BELOW NORMAL WITH HIGHS IN THE UPPER 30S/LOW 40S.
DR
&&
.AVIATION...
942 PM MST FRI FEB 10 2012
FOR THE 06Z TAFS...ONGOING ON AND OFF SNOW WILL CONTINUE TO
CONTRIBUTE TO BOUNCING CIGS/VIS BETWEEN LOW VFR AND IFR AT KGLD
WHICH WILL CONTINUE THROUGH THE OVERNIGHT HOURS. SNOW WILL
DECREASE TOWARDS 12Z AT WHICH TIME CONDITIONS WILL IMPROVE TO VFR WITH
A CLOUD DECK AROUND 5K FEET. AT KMCK...WITH DRYING OF THE LOW
LEVELS...HARD PRESSED TO SEE ANY SNOW WHICH WILL KEEP KMCK VFR
THROUGH THE PERIOD WITH MAINLY MID CLOUDS THROUGH THE PERIOD.
WINDS WILL SWITCH FROM THE NORTHEAST TO THE SOUTHEAST TOWARD
MIDDAY ON SATURDAY AS SURFACE HIGH PRESSURE MOVES TO THE EAST.
BAS
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
NE...NONE.
CO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1217 AM EST SAT FEB 11 2012
.Update...
Issued at 715 PM EST Feb 10 2012
Regional radars this evening show the first wave of precipitation
has all but exited the forecast area. Back to the west precipitation
has increased in coverage both ahead of and just behind the cold
front. Have decreased pops over the eastern portion of the forecast
area for the next few hours ahead of this next batch of snow. With a
bit of warmer air filtering in ahead of the front, there have been
some reports of sleet in southern Indiana and west central Kentucky,
so have included this in the grids for a few hours. However, a
change over to all snow is still expected. Updated grids have
already been sent. Products will be out soon.
.Short Term (Today and Tonight)...
Updated at 317 PM EST Feb 10 2012
First in a series of mid-level wave continues to push eastward into
the lower Ohio Valley this afternoon. Out ahead of this feature,
widespread precipitation shield has been affecting southern Indiana
and central Kentucky this afternoon. Colder thermal profiles across
the north have resulted in precipitation remaining in the form of
snow. However, across southern Kentucky, slightly warmer air aloft
has worked into that region which has resulted in a mix of rain
and/or just plain rain in areas down around Bowling Green and
Glasgow. This band of precipitation continues to head east and will
likely clear the I-65 corridor by 5PM EST and the Bluegrass region
by 7-8 PM tonight. Temperatures this afternoon have warmed into the
upper 30s in the west and with lower 30s in the east. Temperatures
have been taking a dip when the snow bands have moved through...then
have rebounded by a couple of degrees once the precipitation had
ended. For the remainder of the afternoon...we expect temperatures
to remain close to their current values and actually rise a degree
or two once the precipitation has ended as southerly flow attempts
to bring a little warmer air into the area ahead of the approaching
cold front to the northwest of the region. Snowfall accumulations
of a dusting or so will be possible with this afternoon snow
activity...but do not be surprised to see it melt rather quickly
once the precipitation ends. With temps expected to remain above
freezing this afternoon and this evening...am not anticipating much
in the way of travel problems for the afternoon rush and for evening
activities.
For Tonight, the next weather feature will be a strong cold front
that will surge through the region. Currently the front out to our
west near St. Louis. The front has been moving a bit slower than
the models had been forecasting an it is expected to hit our area a
little later than previously forecast. As the front approaches,
temperatures will likely rise slightly and we`ll see a return of
snow showers. The front looks to pass through the I-65 corridor
between 11P-12A EST tonight and then through the I-75 corridor by
2-3AM. Colder air will quickly rush in behind the front and
temperatures will fall into the lower 20s by sunrise on Saturday.
The latest HRRR, our local Hi-Res ARW WRF, and RUC data all show
snow shower activity occurring ahead and behind the front. Vertical
sounding profiles actually have a bit of a convective look to them
and I would not be surprised to see more of a snow shower/snow
squall type of activity to develop later tonight. In addition, the
pressure gradient will really tighten up and winds of 15-20 MPH with
gusts up to 30 MPH will be possible. These snow showers will be the
ones that bring the accumulating snow to the region. The snow
combined with temperatures falling into the lower 20s will result in
slick spots developing later tonight. Therefore we will leave the
current winter weather advisory intact...though much of the expected
snowfall and hazardous travel conditions will be delayed until later
tonight and into Saturday morning.
The front will continue to surge eastward on Saturday and
precipitation will end from west to east during the morning hours.
The models are trying to develop a fetch off of Lake Michigan.
However, the models have been often too aggressive with these during
this winter. Nonetheless...some snow shower activity looks to
persist into the morning hours on Saturday and that will likely add
a little more accumulation over in the Bluegrass region. Skies will
likely remain mostly cloudy through much of the day with
temperatures remaining in the 20s. Surface winds will remain
elevated during the day with winds of 10-20 MPH and gusts up to 25
MPH or so. This will keep wind chills down in the single digits at
times on Saturday.
As far as snowfall accumulations...the consensus guidance suggests
around an inch of accumulation for areas generally north of the WK
and BG Parkways. Little accumulation is expected in the far south
and southwest where a 1/2 inch or less will be possible. Highest
accumulations are going to be in the northeast generally east of
U.S. 27 where 1-2 inches of snowfall will be possible by the time
precipitation comes to an end on Saturday.
.Long Term (Saturday Night - Friday)...
Updated at 300 PM EST Feb 10 2012
1040mb high pressure will be over the central Plains Saturday night,
with an equally significant low off the New England coast. The
gradient in between will mean northwesterly winds that will just
start to weaken some as the night progresses. By the day Sunday, the
high will move to around Arkansas, making the strongest winds over
the Bluegrass and weaker across the southwest forecast area.
Temperatures will remain chilly however, with readings only getting
up to around freezing for highs. Wind chills Sunday morning again
look to be in the single digits for most of the area.
The next weather system to impact the region still looks to be
Monday night. Multiple waves within a strengthening southwesterly
flow will allow for precip all along the MS river valley Monday
afternoon and expect this moisture to advect east for the night.
Given forecast temperatures, expect at least a wintry mix for the
night, if not all snow for the north. By midnight, most of the
region should be into light to moderate snow. We could have another
advisory level event over southern Indiana with still some potential
over norther central Kentucky, but it is too early to be that
specific.
The difference with this system, compared to tonight`s snows, will
be that it looks to be followed by some warming for midweek. Models
are still not handling the longer term that well, so do not have
high confidence at this point. The 12Z GFS had a vortmax cross the
region Wednesday that was not in the previous forecast. the 00Z
ECMWF and now the 12Z have hinted at this as well, but there is not
much moisture associated with the impulse. Conversely, the system
that was expected for Thursday has now backed off as well in the 12Z
GFS, but the new ECMWF continues with a large storm system moving
into the midwest. Given such run-to-run inconsistency, will keep in
some precip chances each day, though with lower pops. Also, have
leaned more towards the precip type as rain, with highs into the 50s
Wednesday through Friday.
&&
.Aviation (06Z TAF Issuance)...
Updated at 0017 AM EST Feb 11 2012
Winds will increase abruptly from the northwest once a strong cold
front passes through each TAF site. Northwest winds will have
already arrived at SDF with winds averaging 15kt with gusts up to
25kt.
At BWG, expect a sharp wind shift to the northwest around 0530Z. At
LEX, winds will shift to the northwest around 08z. As this front
exits the region, blustery northwest winds will continue all the way
through 00z Sunday. with winds averaging 15 to 18kt and gusts up to
30kt at times around 18z.
Light snow showers and flurries will continue at SDF and BWG through
09z with visibilities remaining above 4sm within the heaviest
showers. After 09z, just flurries with VFR visibilities are
expected. Ceilings at BWG and SDF will rise to over 1k feet after
07z and stay within the MVFR range through 14z.
At LEX, light snow and snow showers will continue longer, through
12z with occasional high end IFR ceilings. Ceilings will rise
gradually after 14z at LEX into the MVFR range.
After 18z, broken clouds will scatter out at SDF and BWG, while
remaining broken to overcast in the MVFR range at LEX. Brisk
northwest winds will finally start to diminish to around 11kt around
00z Sunday.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...WINTER WEATHER ADVISORY UNTIL NOON EST /11 AM CST/ TODAY FOR
INZ076>079-083-084-089>092.
KY...WINTER WEATHER ADVISORY UNTIL NOON EST /11 AM CST/ TODAY FOR
KYZ023>043-045>049-053>057-061>067-070>078-081-082.
$$
Update...........EER
Short Term.......MJ
Long Term........RJS
Aviation.........JSD
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
447 AM EST SAT FEB 11 2012
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 446 AM EST SAT FEB 11 2012
LATEST WV IMAGERY AND RUC ANALYSIS REVEALS THE CENTER OF THE POLAR
VORTEX EAST OF HUDSON BAY WITH A MID/UPPER LEVEL TROUGH AXIS
EXTENDING SOUTH INTO THE CENTRAL GREAT LAKES. AT THE SFC...A 1044 MB
ARCTIC HIGH WAS CENTERED OVER THE DAKOTAS. RADAR IMAGERY AND SFC OBS
SHOW WIND PARALLEL LES BANDS FROM EAST OF MQT TO GRAND MARAIS BEING
SUPPORTED BY ENHANCED LOW-LVL CONVERGENCE FROM NW WIND FLOW ACROSS
MUCH OF LAKE SUPERIOR AND THEN LAND BREEZE CIRCULATION OFF OF
ONTARIO CAUSING A NE WIND OVER FAR ERN LAKE SUPERIOR. LES BANDS WITH
RETURNS TO 30 DBZ ARE FAIRLY WELL SPACED APART DUE TO VERY DRY
UPSTREAM AND LARGE SCALE ANTICYCLONIC FLOW ACROSS THE AREA. SURGE OF
MID TO LOW-LVL MOISTURE IN WAA PATTERN MOVING IN FROM NORTH OF LAKE
SUPERIOR IS SHOWING SIGNS OF ENHANCING LES BANDS ACROSS THE LAKE IN
THE PAST HR OR SO. THIS WILL BE SOMETHING TO MONITOR AS THE DAY
PROGRESSES TO SEE IF IT WILL BOOST LES ACCUMS DOWNWIND OF THE LAKE.
TODAY...AS 850-700 MB MOISTURE INCREASES IN A DEVELOPING WAA PATTERN
THERE COULD BE A BRIEF INCREASE IN LES INTENSITY FOR THE ERN
COUNTIES FAVORED BY A WNW/NW WIND. AS I SAID...BELIEVE ANY FLARE UP
IN LES WILL BE SHORT-LIVED SINCE WAA AND RISING 850 MB TEMPS WILL
EVENTUALLY FORCE THE DGZ ABV THE BEST OMEGA/UPWARD MOTION WITHIN THE
CONVECTIVE BOUNDARY LAYER BY THE LATE AFTERNOON/EVENING HRS. LONGER
FETCH ACROSS THE LAKE ALONG WITH MORE FAVORABLE LES PARAMETERS
SUGGEST BEST SNOW ACCUMULATIONS WILL BE OVER THE NE FCST
AREA...WHERE AMOUNTS IN THE 2 TO 4 INCH RANGE ARE POSSIBLE...JUST
BLO ADVISORY CRITERIA. ELSEWHERE...NEAR LAKE SUPERIOR EXPECT LES
AMTS GENERALLY 2 INCHES OR LESS.
TONIGHT...TROF ASSOCIATED WITH POLAR VORTEX E OF HUDSON BAY WILL
BEGIN SHIFTING E OF THE REGION...ALLOWING FOR PROMINENT RIDGING AND
WAA REGIME TO SET UP AND CONTINUE INTO SUN. LES WILL BE ONGOING SAT
EVENING OVER THE E AT LOCATIONS FAVORED BY A WNW/NW WIND OFF LAKE
SUPERIOR. HOWEVER...INVERSION QUICKLY SETTLES DOWN TO 4KFT OR LWR BY
LATE EVENING AND OVERNIGHT. ALSO...CONTINUED WAA WILL KEEP THE
DENDRITIC SNOW GROWTH TEMP ZONE (DGZ) UP ABOVE BEST UPWARD MOTION.
IN GENERAL...MIGHT SEE ANOTHER 1-2...POSSIBLY UP TO 3 INCHES OF SNOW
OVER THE NE FCST AREA SAT NIGHT. OUT W...INVERSION WILL ALREADY BE
SETTLING TO 3KFT OR LWR EARLY IN THE EVENING WITH DGZ ABOVE THE
INVERSION. GIVEN THE LOW INVERSION AND MODERATING AIRMASS...THERE
MAY NOT BE MUCH LEFT OTHER THAN FLURRIES THIS EVENING WITH GRADUAL
CLEARING THEN FOLLOWING DURING THE NIGHT FROM THE W. WITH
CLEARING...MINS COULD DROP NEAR ZERO IN THE TRADITIONAL COLD SPOTS
OVER THE INTERIOR W HALF. NEAR LAKE SUPERIOR WHERE THERE WILL BE
BETTER MIXING AND MODERATION FROM ONSHORE NW FLOW TO KEEP MIN TEMPS
IN THE TEENS.
SUNDAY...LINGERING LIGHT LES/FLURRIES OVER THE NE FCST AREA WILL END
IN THE MORNING AS THE INVERSION CONTINUES TO LWR AND MORE
IMPORTANTLY TEMPS AT INVERSION BASE RISE ABOVE -10C. AWAY FROM
DIMINISHING LIGHT LES E...IT SHOULD TURN OUT TO BE A MAINLY SUNNY
DAY UNDER A DEEP DRY AIR MASS. DRY AIR MASS AND SUNSHINE WORKING ON
THE LWR ALBEDO FORESTED LANDSCAPE OF UPPER MI WILL ASSIST THE WARM
UP...BUT STRONG INVERSION WILL HOLD BACK THE WARMING POTENTIAL OVER
WHAT IT COULD BE. FCST SOUNDINGS SUGGEST MIXING TO JUST ABV 925 MB
LOOK FOR HIGHS GENERALLY IN THE MID/UPPER 20S.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 446 AM EST SAT FEB 11 2012
UPPER TROUGH WILL BE ROTATING E OF THE AREA AT THE START OF THE LONG
TERM PERIOD...LEADING TO THE AREA BEING BETWEEN THE SPLIT FLOW OF
THE NRN STREAM RIDGE OVER THE CANADIAN PRAIRIES AND THE SRN STREAM
RUNNING ACROSS THE SRN FOURTH OF THE CONUS. THIS WILL KEEP THE AREA
UNDER QUIET WEATHER TO START THE PERIOD WITH A HIGH PRESSURE RIDGE
PUSHING OVER THE WRN CWA SUN NIGHT AND MON...WHILE BROAD H850-700
WAA INTENSIFIES OVER STATIONARY FRONT OVER SE ONTARIO.
SUN NIGHT...EXPECT A MOSTLY CLEAR NIGHT WITH THE HIGH PRESSURE RIDGE
PUSHING OVER THE AREA. LOWS WILL DEPEND ON HOW QUICKLY WINDS CAN
DECOUPLE ON MON NIGHT...AS GRADIENT BETWEEN STATIONARY FRONT AND
APPROACHING SFC RIDGE TRIES TO KEEP WINDS UP. BEST CHANCE FOR LIGHT
WINDS WILL BE CLOSER TO THE SFC RIDGE OVER THE SW HALF OF THE
CWA...WHERE PWAT VALUES FALL TO 40 PERCENT OF NORMAL. HAVE TRENDED
TOWARDS THE LOW END OF GUIDANCE...BUT NOT QUITE AS COLD AS IF THE
WAS HIGHER CONF FOR LIGHT WINDS.
MON...AREA WILL BE BETWEEN SFC TROUGH IN SE ONTARIO AND H500
SHORTWAVE AND ASSOCIATED HEIGHT FALLS MOVING THROUGH THE MID MISS
VALLEY AND APPROACHING THE LOWER GREAT LKS MON NIGHT. EXPECT A
MOSTLY SUNNY DAY FOR MUCH OF THE AREA...ALTHOUGH CLOUDS WILL ATTEMPT
TO PUSH ACROSS THE WI BORDER LATE IN THE AFTN WITH MOISTURE
INCREASING AHEAD OF THE SHORTWAVE. HIGHS WILL DEPEND ON AMNT OF
MIXING. MODELS INDICATING MIXING UP TO H900...WHICH WOULD PRODUCE
HIGHS OF 30-35. WITH ABUNDANT SUNSHINE TO START THE DAY...FELT TEMPS
WILL WARM UP QUICKLY AND ONLY MADE A DEGREE OR TWO ADJUSTMENT UP TO
GOING HIGHS.
MODELS CONSISTENT IN H850-650 MOISTURE MOVING INTO THE SRN HALF OF
THE AREA MON NIGHT AS THE SHORTWAVE MOVES SOUTH OF THE CWA. BUT WITH
LACK OF ISENTROPIC ASCENT...WAA...AND MAIN FORCING S OF THE CWA WITH
H500 HEIGHT FALLS...THINK PCPN CHANCES ARE FAIRLY LIMITED.
THEREFORE...HAVE JUST A SLIGHT CHANCE OVER THE SCNTRL CWA AND
CHANCES BRUSHING THE CITY OF MENOMINEE.
DAYS 4 THROUGH 7 /TUES THROUGH FRIDAY/...
SRN STREAM TROUGH WILL BEGIN TO DIG OVER THE SW CONUS ON
TUES...ALLOWING RIDGING TO DEVELOP OVER THE SRN/CNTRL PLAINS AND
CONTINUE INTO WED. MEANWHILE...TROUGH WILL START TO AMPLIFY OVER THE
CANADIAN ROCKIES IN THE NRN STREAM ON TUES AND ATTEMPT TO MERGE WITH
THE SRN STREAM WED NIGHT INTO THURS. THESE SITUATIONS TEND TO BE
DIFFICULT FOR MODELS...BUT 00Z GFS/ECMWF/GEM AND ASSOCIATED ENS
MEANS HANDLE THE LARGE SCALE FEATURES SIMILARLY BUT DO HAVE
DIFFICULTY WITH THE EMBEDDED SHORTWAVES. THUS...HAVE AVERAGE CONF
FOR MUCH OF THE EXTENDED PERIOD.
INITIAL SYSTEM EXITS THE AREA ON TUES...LEAVING AREA IN WSWRLY LLVL
FLOW AND H850 TEMPS AROUND -8C. THIS PROVIDES LIMITED POTENTIAL FOR
LES AND WILL LIKELY SEE MOSTLY CLOUDY SKIES LINGERING INTO WED WITH
NEXT POTENTIAL SHORTWAVE MOVING THROUGH...ALTHOUGH MODELS HAVE LARGE
DIFFERENCES IN INTENSITY.
NRN/SRN STREAMS LOOK TO PHASE ON THURS. WITH THE MORE DOMINATE SRN
STREAM...EXPECT SFC LOW DEVELOPMENT TO FOLLOW THE SRN STREAM TRACK
THAT WILL LIKELY TAKE IT THROUGH THE OHIO VALLEY OR LOWER GREAT LKS.
THIS WOULD BRUSH THE SE CWA AS BEST FORCING/MOISTURE REMAINS CLOSER
TO THE LOW. 00Z ECMWF DID TREND A LITTLE FARTHER NW WITH THE TRACK
OF THE LOW...SO WILL NEED TO WATCH ON FUTURE SHIFTS.
MODELS BEGIN TO DIVERGE HEADING INTO FRI WITH THE HANDLING OF THE
NRN STREAM FEATURES AND WHERE THE SRN STREAM UPPER TROUGH IS LOCATED
OVER THE SW CONUS. H850 TEMPS AROUND -11C WOULD LEAD TO SOME LES
POTENTIAL UNDER NW WINDS...BUT LLVL MOISTURE OVER THE W MAY BE
LIMITED. THEREFORE...ONLY MENTIONED CHANCE POPS OVER THE ERN AREAS
FAVORED BY NW WINDS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1228 AM EST SAT FEB 11 2012
LES IS EXPECTED TO REDEVELOP AT CMX AND IWD OVERNIGHT AS MOISTURE
INCREASES AGAIN WITH NW FLOW. HOWEVER...MAINLY MVFR CONDITIONS WILL
PREVAIL WITH ONLY BRIEF PERIODS OF IFR POSSIBLE. AT SAW...LES WILL
MOVE OVER TONIGHT BEFORE WINDS BECOME MORE NWLY LATE TONIGHT.
ANOTHER SURGE OF MOISTURE WILL PUSH INTO THE AREA EARLY SAT
AFTERNOON...INTENSIFYING LES AT CMX AND IWD.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 446 AM EST SAT FEB 11 2012
NNW WINDS TO 30KT WILL PERSIST WITH AMPLE INSTABILITY IN THE ARCTIC
AIRMASS MOVING OVER THE REGION. NW WINDS APPROACHING GALES TO 35 KT
ARE ALSO POSSIBLE THIS AFTERNOON INTO THIS EVENING OVER ERN LAKE
SUPERIOR. EXPECT HEAVY FREEZING SPRAY ACROSS THE ENTIRE LAKE THROUGH
TONIGHT WITH THE STRONG WINDS AND WAVE ACTION. LOOK FOR HEAVY
FREEZING SPRAY TO END ON SUNDAY AS THE AIRMASS WARMS AND WINDS
GRADUALLY DIMINISH. CONDITIONS WILL QUIET DOWN FOR THE EARLY PART OF
THE WORK WEEK AS A HIGH PRES RIDGE MOVES OVER THE UPPER GREAT LAKES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST /6 AM CST/ SUNDAY
FOR LSZ162-240>251-263>267.
GALE WARNING FROM 5 PM THIS AFTERNOON TO 3 AM EST SUNDAY FOR
LSZ248>250-265-266.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...SRF
AVIATION...TITUS
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1230 AM EST SAT FEB 11 2012
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 423 PM EST FRI FEB 10 2012
WV IMAGERY AND RUC ANALYSIS INDICATED CENTER OF THE POLAR VORTEX
EAST OF HUDSON BAY WITH A MID/UPPER LEVEL TROUGH AIX TO THE
SOUTHWEST THROUGH ERN LAKE SUPERIOR INTO CTNRL WI. AT THE SFC...A
1046 MB ARCTIC HIGH WAS LOCATED OVER SASK WITH A RIDGE EXTENDING
INTO NRN ONTARIO AND THROUGH THE PLAINS. NNW WINDS IN THE VERY COLD
AIRMASS SUPPORTED LES FOR LOCATIONS FAVORED BY NRLY WINDS.
HOWEVER...LES WAS DIMINISHING AND BANDS WERE SHIFTING WITH THE ACYC
FLOW...BACKING WINDS AND VERY DRY AIR WELL MIXED LOW LEVEL AIR
UPSTREAM WITH SFC DEWPOINTS TO NEAR -20F.
TONIGHT...WITH 850MB TEMPS AROUND -20C...LES WILL BE ONGOING IN
AREAS FAVORED BY NW WINDS. THE DRY AIR AND LOW INVERSION AOB 3KFT
WILL KEEP LES LIGHT INITIALLY. HOWEVER...WITH THE DENDRITIC SNOW
GROWTH TEMP ZONE (DGZ) FIRMLY IN THE CONVECTIVE LAYER...SHOULD STILL
BE ABLE TO GET A FEW INCHES OF FLUFFY SNOW MAINLY OVER THE NE FCST
AREA WHERE ENOUGH MOISTENING CAN OCCUR DESPITE THE DRY AIR.
WINDS OVER FAR SW UPPER MI MAY BACK SUFFICIENTLY TO CUT OVERWATER
TRAJECTORIES ENOUGH TO ALLOW FOR SOME CLEARING. EXPECT TEMPS THERE
TO FALL INTO THE SINGLE DIGITS BLO ZERO. ELSEWHERE...TEMPS ARE
EXPECTED TO REMAIN IN THE SINGLE DIGITS AND LOWER TEENS AS SFC-925MB
WINDS GENERALLY MAINTAIN SOME MODIFICATION OFF OF LAKE SUPERIOR.
SATURDAY...EXPECT LES INTENSITY TO INCREASE BY SAT AFTERNOON AS
850-700 MB MOISTURE INCREASES IN A DEVELOPING WAA PATTERN. WITH
850MB TEMPS MODERATING THROUGH THE DAY THE DGZ WILL CLIMB...BECOMING
MORE FAVORABLY POSITIONED IN THE CONVECTIVE LAYER/UPWARD MOTION
REGION. LONGER FETCH AND LONGER DURATION OF MORE FAVORABLE LES
PARAMETERS SUGGEST BEST SNOW ACCUMULATIONS WILL BE OVER THE NE FCST
AREA...WHERE AMOUNTS IN THE 2 TO 4 INCH RANGE ARE EXPECTED.
OVER WRN LAKE SUPERIOR...FLOW IS MORE WESTERLY AND ENHANCED
CONVERGENCE COULD DEVELOP BTWN THE PORCUPINE MTNS AND HOUGHTON. THIS
AREA OVER THE WRN CWA COULD ALSO SEE INCREASE IN LES.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 423 PM EST FRI FEB 10 2012
CURRENT PUSH OF ARCTIC AIR INTO THE UPPER LAKES WILL BE SHORT LIVED
AS POLAR VORTEX E OF HUDSON BAY RETREATS/REFORMS BACK TOWARD THE
POLE NEXT WEEK. THE RETREAT OF THE NRN STREAM AND A DISTINCT SPLIT
FLOW REGIME NEXT WEEK WILL BRING A RETURN OF THIS WINTERS PREVAILING
THEME OF ABOVE NORMAL TEMPS. WHETHER OR NOT THIS SPLIT FLOW LEADS TO
ANY SRN STREAM SYSTEMS REACHING THE UPPER GREAT LAKES REMAINS TO BE
SEEN. AT THIS POINT...IT STILL APPEARS THAT THE OVERALL DRY PATTERN
WILL PERSIST NEXT WEEK THOUGH THERE ARE MUCH INCREASED UNCERTAINTIES
IN POSSIBLE STREAM INTERACTIONS THAT MAY LEAD TO SOME STORMINESS IN
THE GREAT LAKES LATE IN THE WEEK.
BEGINNING SAT NIGHT...TROF ASSOCIATED WITH POLAR VORTEX E OF HUDSON
BAY WILL BEGIN SHIFTING E...RESULTING IN THE BEGINNINGS OF A WAA
REGIME WHICH WILL CONTINUE THRU SUN. LES WILL BE ONGOING SAT EVENING
OVER THE E AT LOCATIONS FAVORED BY A WNW/NW WIND OFF LAKE SUPERIOR.
HOWEVER...INVERSION QUICKLY SETTLES DOWN TO 4KFT OR LWR LATE EVENING
AND OVERNIGHT. ALSO...WAA BEGINS TO SHIFT DENDRITIC SNOW GROWTH TEMP
ZONE (DGZ) UP ABOVE BEST UPWARD MOTION. IN GENERAL...MIGHT SEE
ANOTHER 1-2 MAYBE 3 INCHES OF SNOW OVER THE NE FCST AREA SAT NIGHT.
OUT W...INVERSION WILL ALREADY BE SETTLING TO 3KFT OR LWR EARLY IN
THE EVENING WITH DGZ ABOVE THE INVERSION. GIVEN THE LOW INVERSION
AND MODERATING AIRMASS...THERE MAY NOT BE MUCH LEFT OTHER THAN
FLURRIES SAT EVENING WITH GRADUAL CLEARING THEN FOLLOWING DURING THE
NIGHT FROM THE W. FROM AN ISENTROPIC STANDPOINT...CONDENSATION PRES
DEFICITS ARE QUITE HIGH SAT NIGHT IN DEVELOPING WAA REGIME...SO
THERE SHOULDN`T BE MUCH IN THE WAY OF WAA CLOUDINESS. ALTHOUGH SKIES
WILL BE CLEARING FROM THE W...MAY NOT BE ABLE TO DECOUPLE COMPLETELY
AS A STRONG PRESSURE GRADIENT STILL EXISTS BETWEEN A 1040MB HIGH
SINKING INTO THE CENTRAL PLAINS AND A 1008MB TROUGH OVER WESTERN
HUDSON BAY/FAR NRN ONTARIO. MINS SHOULD END UP NEAR ZERO IN THE
TRADITIONAL COLD SPOTS OVER THE INTERIOR W HALF...RANGING UP TO THE
TEENS E NEAR LAKE SUPERIOR.
LINGERING LIGHT LES OVER THE NE FCST AREA WILL END SUN AS INVERSION
CONTINUES TO LWR AND MORE IMPORTANTLY TEMPS AT INVERSION BASE RISE
ABOVE -10C. AWAY FROM DIMINISHING LIGHT LES E...SUN SHOULD TURN OUT
TO BE A MAINLY SUNNY DAY UNDER A DEEP DRY AIR MASS. DRY AIR MASS AND
SUNSHINE WORKING ON THE LWR ALBEDO FORESTED LANDSCAPE OF UPPER MI
WILL ASSIST THE WARM UP...BUT STRONG INVERSION WILL HOLD BACK THE
WARMING POTENTIAL OVER WHAT IT COULD BE. FCST SOUNDINGS SUGGEST
MIXING TO 900MB...BUT THAT MIGHT BE A LITTLE OPTIMISTIC. MID/UPPER
20S SHOULD BE THE RULE.
POLAR VORTEX WILL BE RETREATING MON WITH UPSTREAM SPLIT FLOW
ADVANCING INTO THE CNTRL CONUS. IN THE SPLIT...MODEL GUIDANCE
CONTINUES TO INDICATE A SRN STREAM SHORTWAVE MOVING INTO THE MID
MISSISSIPPI VALLEY LATE MON. THERE HASN`T BEEN MUCH MODEL SPREAD
WITH THIS SYSTEM IN RECENT RUNS...AND LATEST ROUND OF GUIDANCE
MAINTAINS THE IDEA THAT THE BULK OF ASSOCIATED PCPN WILL PASS S OF
UPPER MI. SEE NO REASON TO STRAY FROM THAT SCENARIO RIGHT NOW.
SO...CLEAR SKIES SUN NIGHT WILL GIVE WAY TO A SLOW INCREASE IN
HIGH/MID CLOUDS FROM THE SW MON. MAINTAINED SLIGHT CHC POPS ACROSS
THE FAR S/SE MON NIGHT AS THE NRN FRINGE OF PCPN MAY BRUSH THAT
AREA.
TUE THRU FRI...UNDER SPLIT FLOW WITH MORE PROGRESSIVE NRN STREAM...
ARCTIC AIR WILL BE BOTTLED UP WELL TO THE N DURING THE MIDDLE AND
END OF NEXT WEEK. BENIGN/DRY WEATHER SHOULD CONTINUE TUE/WED. EVEN
LES WON`T BE A CONCERN WITH CONSENSUS 850MB TEMPS WARMER THAN -8C.
HEADING INTO THU/FRI...SOME RECENT GFS RUNS HAVE SUGGESTED POSSIBLE
STREAM INTERACTIONS SOMEWHERE FROM THE MISSISSIPPI VALLEY EASTWARD
THAT COULD LEAD TO A STORM SYSTEM IN THE GREAT LAKES AREA. TODAYS
12Z ECMWF RUN IS NOW BEGINNING TO SUGGEST THAT AS WELL. AS ALWAYS...
THERE IS LOW CONFIDENCE IN STREAM PHASING...AND IT GOES WITHOUT
SAYING THAT THERE IS TREMENDOUS UNCERTAINTY IN ANY TYPE OF
INTERACTION THAT FAR OUT IN A MODEL RUN. WILL BE SOMETHING TO
MONITOR IN THE COMING DAYS...BUT FOR NOW...FAVORED THE MORE
DISTINCT...SEPARATED FLOW REPRESENTED BY PREVIOUS ECMWF RUNS. AS A
RESULT...MAINTAINED A DRY FCST FOR THU/FRI THOUGH THERE COULD BE A
LITTLE -SN AT SOME POINT. AIR MASS REMAINS WARM ENOUGH TO PRECLUDE
ANY MENTION OF LES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1228 AM EST SAT FEB 11 2012
LES IS EXPECTED TO REDEVELOP AT CMX AND IWD OVERNIGHT AS MOISTURE
INCREASES AGAIN WITH NW FLOW. HOWEVER...MAINLY MVFR CONDITIONS WILL
PREVAIL WITH ONLY BRIEF PERIODS OF IFR POSSIBLE. AT SAW...LES WILL
MOVE OVER TONIGHT BEFORE WINDS BECOME MORE NWLY LATE TONIGHT.
ANOTHER SURGE OF MOISTURE WILL PUSH INTO THE AREA EARLY SAT
AFTERNOON...INTENSIFYING LES AT CMX AND IWD.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 423 PM EST FRI FEB 10 2012
NNW WINDS TO 30KT WILL PERSIST WITH AMPLE INSTABILITY IN THE ARCTIC
AIRMASS MOVING OVER THE REGION. NW WINDS APPROACHING GALES TO 35 KT
ARE ALSO POSSIBLE SAT AFTERNOON INTO SAT EVENING OVER ERN LAKE
SUPERIOR. EXPECT HEAVY FREEZING SPRAY ACROSS THE ENTIRE LAKE TONIGHT
THROUGH SAT NIGHT WITH THE STRONG WINDS AND WAVE ACTION. LOOK FOR
HEAVY FREEZING SPRAY TO END ON SUNDAY AS THE AIRMASS WARMS AND WINDS
GRADUALLY DIMINISH. CONDITIONS WILL QUIET DOWN FOR THE EARLY PART OF
THE WORK WEEK AS A HIGH PRES RIDGE MOVES OVER THE UPPER GREAT LAKES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST /6 AM CST/ SUNDAY
FOR LSZ162-240>251-263>267.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...ROLFSON
AVIATION...TITUS
MARINE...JLB
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
249 AM CST SAT FEB 11 2012
.SHORT TERM...TONIGHT THROUGH MONDAY NIGHT
249 AM CST SAT FEB 11 2012
MAIN FORECAST CONCERN IS ON PRECIPITATION FOR MONDAY
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS
SHOWED TROUGHING COMING INTO CALIFORNIA...RIDGING FROM ARIZONA INTO
SASKATCHEWAN...AND TROUGHING FROM QUEBEC INTO ILLINOIS. THE FORECAST
AREA LIES IN SUBSIDENCE IN THE WAKE OF THE TROUGHING...PROMOTING A
FEED OF DRIER AIR INTO THE FORECAST AREA. 00Z MPX SOUNDING AS WELL
AS A PRECIPITABLE WATER PLOT OF 00Z RAOB DATA ACROSS THE UPPER
MIDWEST REFLECTIVE OF THE DRY AIR...WITH VALUES AROUND 0.05 OF AN
INCH OR 25 PERCENT OF NORMAL. WITH ALL THE DRY AIR...SKIES ARE
CLEAR. ARCTIC AIR SLOWLY FLOWING IN TOO WITH THE DRY AIR ON A
SUSTAINED 10 TO 15 MPH NORTHWEST WIND. TEMPERATURES HAVE FALLEN INTO
THE SINGLE DIGITS ABOVE ZERO. THE LACK OF SNOW COVER AND PERSISTENT
WIND KEEPING TEMPERATURES FROM FALLING MUCH LOWER. COMBINATION OF
THE WIND AND TEMPERATURES RESULTING IN WIND CHILLS MOSTLY IN THE
SINGLE DIGITS OR TEENS BELOW ZERO. AREA OF HIGH PRESSURE ASSOCIATED
WITH THE SUBSIDENCE FAR OFF TO THE WEST...OVER THE DAKOTAS. NO BIG
CHANGE IN 850MB TEMPS FROM 12Z FRI TO 00Z SATURDAY AT BIS...ABR AND
MPX...ALL SITTING BETWEEN -17 AND -20C. HOWEVER...DVN AND GRB WHICH
WERE ALONG THE ARCTIC FRONT AT 12Z DROPPED 9 TO 11C BY 00Z.
TODAY THROUGH SUNDAY...UPPER RIDGING SEEN OVER ARIZONA AND UTAH IS
FORECAST TO BUILD EAST INTO THE PLAINS AND EVENTUALLY THE UPPER
MISSISSIPPI RIVER VALLEY BY LATE SUNDAY...DUE TO TROUGHING MOVING
INTO THE ROCKIES AND FOUR CORNERS REGION. THE FORECAST AREA WILL
REMAIN ON THE EAST SIDE OF THE UPPER RIDGING...PROMOTING SUBSIDENCE
AND CONTINUED DRY AIR ADVECTION. HOWEVER...THE BUILDING HEIGHTS IN
CONJUNCTION WITH THE LACK OF SNOW COVER AND PLENTY OF SUN SHOULD
HELP THE ARCTIC AIRMASS MODERATE THIS WEEKEND. 850MB TEMPS REFLECT
THE MODERATING...CLIMBING TO AROUND -12C AT 00Z SUNDAY AND -6C AT
00Z MONDAY. THE DRY AIRMASS IN PLACE SHOULD ALSO PROMOTE GOOD
MIXING. GIVEN 850MB TEMPS TODAY...HIGHS ARE ONLY EXPECTED IN THE MID
TEENS TO AROUND 20. THE BLUSTERY NORTHWEST WIND WILL MAKE IT FEEL
COOLER...THOUGH...WITH WIND CHILLS ONLY CLIMBING TO AROUND ZERO.
PLENTY OF WIND ANTICIPATED TONIGHT GIVEN THE SURFACE RIDGE TAKING A
TRACK TO OUR SOUTHWEST. THIS WIND SHOULD KEEP LOWS MOSTLY IN THE
SINGLE DIGITS ABOVE ZERO. ANTICIPATING WE CAN TACK ON ANOTHER 10
DEGREES OF WARMING FOR SUNDAY GIVEN THE 6C JUMP IN 850MB TEMPS.
REGARDING THE WIND CHILL ADVISORY...VERY MARGINAL CONDITIONS AT
BEST. SINCE IT IS ALREADY UP AND WIND CHILLS ARE AT LEAST IN THE
TEENS BELOW ZERO...FIGURE IT IS NOT WORTH CANCELING.
SUNDAY NIGHT THROUGH MONDAY NIGHT...FOCUS TURNS TO THE TROUGHING
OVER THE WESTERN U.S AT 00Z MONDAY. GOOD MODEL AGREEMENT EXISTS FOR
THIS TROUGHING TO CROSS THE PLAINS ON MONDAY...THEN SHEAR APART
MONDAY NIGHT AS IT CROSSES THE FORECAST AREA AND THROUGH THE OHIO
VALLEY. BEST 500MB HEIGHT FALLS FOR THE FORECAST AREA OCCUR MONDAY
AFTERNOON AND EVENING...RANGING FROM 40 TO 70 METERS PER 12 HOURS...
HIGHEST IN THE FAR SOUTHERN SECTIONS OF THE AREA. SO THE DPVA
FORCING IS FAIRLY DECENT. ISENTROPIC LIFT FIELDS...ON THE OTHER
HAND...ARE TERRIBLE WITH BASICALLY VERY LITTLE IF ANY NET ADIABATIC
OMEGA FROM EITHER THE 11.00Z NAM OR GFS. BEST 850 TO 700MB MOISTURE
TRANSPORT ALSO NOT THAT IMPRESSIVE...MOSTLY FOCUSED IN MISSOURI...
ILLINOIS AND ARKANSAS. SO BASICALLY ALL PRECIPITATION PRODUCTION
WILL COME FROM THE 500MB HEIGHT FALLS ACTING ON THE WEAKER MOISTURE
BEING TRANSPORTED UP INTO THE AREA. CERTAINLY GOOD MODEL AGREEMENT
EXISTS OF PRECIPITATION SPREADING SOUTHWEST TO NORTHEAST ACROSS MUCH
OF THE FORECAST AREA ON MONDAY...ESPECIALLY DURING THE AFTERNOON...
WHICH SEEMS REASONABLE. RAISED PRECIPITATION CHANCES UP A LITTLE
MORE FOR THE AFTERNOON...MAINLY ALONG AND SOUTH OF I-90. THINK THE
11.00Z NAM QPF IS A LITTLE TOO HIGH GIVEN LACK OF ISENTROPIC LIFT
AND STRONGER MOISTURE TRANSPORT. STILL...COULD PICK UP ANYWHERE FROM
A HALF INCH TO TWO INCHES OF SNOW OUT OF THE EVENT...HIGHEST ACROSS
THE SOUTH WHERE THE BETTER FORCING IS. PRECIPITATION SHOULD SLOWLY
DIMINISH MONDAY NIGHT AS THE UPPER TROUGHING SHEARS APART...REDUCING
THE DPVA LIFT. REGARDING TEMPERATURES...WITH THE PRECIPITATION AND
CLOUDS TRENDING SLOWER TO MOVE IN FOR SUNDAY NIGHT INTO MONDAY
MORNING...LOWERED TEMPERATURES A FEW DEGREES SUNDAY NIGHT AND STAYED
WITH A NORMAL DIURNAL TREND. POTENTIAL DOES EXIST MONDAY MORNING FOR
A LITTLE SUN NORTH OF I-94...THUS HIGHS ON MONDAY END UP WARMEST
NORTH OF I-94. SOUTHERLY ADVECTION OF WARM AIR AHEAD OF THE TROUGH
SHOULD RESULT IN HIGHS AGAIN IN THE UPPER 20S TO AROUND 30. WITH
PLENTY OF CLOUDS LINGERING MONDAY NIGHT AND LITTLE IN THE WAY OF
COLD ADVECTION...ANTICIPATING TEMPERATURES TO ONLY DROP AROUND 5
DEGREES.
.LONG TERM...TUESDAY THROUGH FRIDAY NIGHT
249 AM CST SAT FEB 11 2012
LONG TERM FORECAST LOOKS A LITTLE MORE UNCERTAIN TODAY...THOUGH THE
FEATURES SEEN YESTERDAY OF A SPLIT FLOW PATTERN REMAIN. THE BIGGEST
UNCERTAINTY IS WEDNESDAY NIGHT AND THURSDAY. DURING THIS PERIOD...
THE NEW 11.00Z ECMWF SUGGESTS TROUGHING COMING OUT OF THE SOUTHWEST
U.S. AND EVENTUALLY PHASING WITH A NORTHERN STREAM SHORTWAVE TROUGH
NEAR THE FORECAST AREA. THE RESULT WOULD PROBABLY BE AN
ADVISORY-TYPE WET SNOW EVENT FOR THE SOUTHEASTERN HALF OF THE
FORECAST AREA. PROBLEM IS...THE ECMWF IS THE ONLY MODEL SHOWING THIS
PHASING POTENTIAL. THE 11.00Z GFS/UKMET KEEP THE TWO SEPARATED WITH
THE SOUTHWESTERN TROUGH EJECTING FARTHER SOUTH. MEANWHILE...THE
11.00Z CANADIAN HAS MORE FOCUS ON THE NORTHERN STREAM FEATURE AND
PRODUCES A FAIRLY AMPLIFIED TROUGH OVER MINNESOTA ON THURSDAY. THE
11.00Z GFS ENSEMBLES DEPICT A SIMILAR AMOUNT OF UNCERTAINTY.
THEREFORE...FOR NOW FOLLOWED A CONSENSUS BLEND FOR PRECIPITATION
CHANCES WHICH END UP 20-40. PLUS...IT IS HARD TO TRUST PHASING THIS
FAR OUT.
OTHERWISE...PRECIPITATION FROM MONDAY NIGHT SHOULD FOR THE MOST PART
END TUESDAY AS THE LINGERING SHORTWAVE TROUGH FALLS APART. THIS
LEAVES DRY CONDITIONS FOR TUESDAY NIGHT AND WEDNESDAY...WHICH SHOULD
ALSO BE ASSOCIATED WITH SOME SMALL 500MB HEIGHT RISES AND A SURFACE
RIDGE OF HIGH PRESSURE. AFTER WHATEVER HAPPENS WITH THE WEDNESDAY
NIGHT THROUGH THURSDAY TIME PERIOD...GOOD AGREEMENT EXISTS OF A
WEST-NORTHWEST FLOW PATTERN HEADING INTO NEXT WEEKEND WITH HARD TO
TIME SHORTWAVES MOVING THROUGH THE FLOW. GIVEN THAT HIGH PRESSURE
SHOULD DOMINATE ACROSS THE SOUTHERN U.S. IN THE WAKE OF THE THURSDAY
SYSTEM...PREVENTING MOISTURE RETURN FROM THE GULF OF MEXICO FOR A
LITTLE WHILE...KEPT CONDITIONS DRY FOR FRIDAY.
ONE THING THAT DOES LOOK CERTAIN FOR THE LONG TERM PERIOD IS
TEMPERATURES TO REMAIN AT OR ABOVE NORMAL. A BRIEF SHOT OF COOL AIR
MAY COME THROUGH ON THURSDAY WITH 850MB TEMPS FALLING TO -6 TO -8C.
STILL...THIS WOULD BE ABOVE NORMAL. STAYED PRETTY MUCH WITH A BLEND
OF ALL GUIDANCE FOR TEMPERATURES AS IT SEEMS REASONABLE AT THIS
POINT.
&&
.AVIATION...THROUGH 06Z SUNDAY
1100 PM CST FRI FEB 10 2012
A TIGHT PRESSURE GRADIENT ON THE EAST SIDE OF AN AREA OF HIGH
PRESSURE OVER THE NORTHERN PLAINS WILL KEEP WINDS UP FROM THE
NORTH-NORTHWEST FOR THE REST OF TONIGHT AND THROUGH MUCH OF SAT.
MOMENTUM TRANSFER VIA BUFKIT SOUNDINGS SUGGEST GUSTS UPWARD OF 20 TO
25 KTS. WOULDN/T BE SURPRISED IF THEY ARE SLIGHTLY HIGHER AT KRST.
THE WINDS WILL WEAKEN BY SUNDOWN SAT...ALTHOUGH LIKELY STILL BE NEAR
10 KTS.
OTHERWISE...VFR CONDITIONS WILL CONTINUE AS THE HIGH PRESSURE
INFLUENCES THE REGION INTO SUNDAY.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
249 AM CST SAT FEB 11 2012
WI...WIND CHILL ADVISORY UNTIL 9 AM CST THIS MORNING FOR WIZ017-029-
034.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS NEW YORK NY
955 AM EST SAT FEB 11 2012
.SYNOPSIS...
DEVELOPING LOW PRESSURE OFF THE MID ATLANTIC COAST THIS MORNING WILL
PASS WELL SOUTHEAST OF LONG ISLAND THIS AFTERNOON. A STRONG COLD
FRONT WILL FOLLOW LATE TODAY INTO THIS EVENING... FOLLOWED BY A
SECOND COLD FRONT SUNDAY AFTERNOON AND EVENING. HIGH PRESSURE WILL
THEN GRADUALLY BUILD FROM THE CENTRAL PLAINS TO THE MID ATLANTIC
COAST THROUGH EARLY NEXT WEEK. A WEAK FRONTAL BOUNDARY NEARBY WILL
APPROACH ON TUESDAY AND LIFT TO THE NORTH. HIGH PRESSURE WILL THEN
BUILD BACK IN FOR THE REST OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
LATEST RADAR AND SATELLITE TRENDS CONTINUE TO INDICATE THAT THE
BULK OF THE HEAVIER SNOW WILL STAY TO OUR EAST...WITH OCCASIONAL
MODERATE SNOWFALL CLIPPING THE EAST END OF THE TWIN FORKS AND FAR
EASTERN NEW LONDON COUNTY. TO THE WEST A GENERAL LIGHT SNOW...WITH
PERIODIC BREAKS SHOULD CONTINUE THROUGH AT LEAST LATE
MORNING...THEN TAPER OFF FROM WEST TO EAST IN THE AFTERNOON.
GENERALLY LOOKING AT UNDER AN INCH AT MOST LOCATIONS...BUT COULD
SEE 1-2 INCHES ON EASTERN PORTIONS OF THE TWIN FORKS AND FAR
EASTERN NEW LONDON COUNTY...PLUS SOME ISOLATED 1-2 INCH AMOUNTS
IN HIGHER ELEVATIONS FROM WESTCHESTER COUNTY ON EAST.
THE STORM CONTINUES TO BASICALLY TRACK EAST FROM THE NC OUTERBANKS
IN RESPONSE TO A SOUTHERN STREAM SHORTWAVE THAT IS NOW JUST SOUTH
OF CAPE LOOKOUT NC. THIS SHORTWAVE FINALLY PIVOTS NE THIS
AFTERNOON...BUT TOO LATE FOR THE COASTAL LOW TO HAVE ANYMORE
IMPACT THAN ABOVE. AN ARGUMENT COULD BE MADE THAT WHAT IS REALLY
DRIVING OUR SNOWFALL IS NOT THE COASTAL LOW/SOUTHERN STREAM
SHORTWAVE AT ALL...BUT LOW TO MID LEVEL BAROCLINICITY OUT AHEAD OF
THE ARCTIC AIRMASS HEADING OUR WAY. WILL ALSO GET A LITTLE
ENHANCEMENT LATE THIS MORNING/EARLY THIS AFTERNOON FROM THE LEFT
EXIT REGION OF A 100 KT 250 HPA JET STREAK.
TEMPERATURE FORECAST WAS RUNNING A TAD HIGH...ADJUSTED DOWN A FEW
DEGREES TO A BLEND OF LAV/MET GUIDANCE WITH NAM AND HRRR 2-METER
TEMPERATURES.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/...
STRONG COLD FRONT AND H5 TROUGH AXIS PASS THROUGH LATE THIS
AFTERNOON/EARLY THIS EVENING...ACCOMPANIED BY ISOLD/SCT SNOW SHOWERS
THAT COULD LEAVE AN ADDITIONAL QUICK COATING OF ACCUMULATION.
STRONG CAA AND A TIGHTENING PRES GRADIENT AS THE OFFSHORE LOW
STRENGTHENS WILL INCREASE OUR WINDS THROUGH THE NIGHT.
UPPER TROUGH AXIS EXPECTED TO BE E OF THE AREA BY SUN MORNING.
COULD SEE SOME SNOW SHOWERS OR SNOW SQUALLS IN THE AFTERNOON AND
EARLY EVENING WITH APPROACH/PASSAGE OF AN ARCTIC COLD FRONT.
FCST SOUNDINGS SHOW NEARLY ADIABATIC LAPSE RATES UP TO 750 MB...
SO A BRIEF GUST TO 40-45 MPH AND EVEN A RUMBLE OF THUNDER IN ANY
SNOW SHOWERS/SQUALLS CANNOT BE TOTALLY RULED OUT.
LOW CHANCE OF LAKE EFFECT SHOW SHOWERS MAKING TO WESTERN ZONES ON
SUNDAY...THOUGH DOWNSLOPING EFFECTS MAY MAKE IT DIFFICULT FOR
PRECIP TO MAKE IT OVER THE MOUNTAINS.
QUITE COLD SAT NIGHT THROUGH SUNDAY NIGHT...WITH LOWS IN THE TENS
TO LOWER 20S...AND HIGHS ONLY 30-35 ON SUNDAY. PRES GRADIENT WILL
REMAIN TIGHT BETWEEN DEPARTING LOW PRES TO THE NE AND HIGH PRES
BUILDING OVER THE OH VALLEY...WITH CONTINUED GUSTY WINDS THROUGH
SUNDAY EVENING...DIMINISHING LATE SUNDAY NIGHT.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
FAIR WX AND A RETURN TO NEAR AVG TEMPS EXPECTED ON MON...WITH HIGH
PRES PASSING TO THE S AND AN ARCTIC COLD FRONT RETREATING NE.
UPPER PATTERN GENERALLY ZONAL THROUGH MOST OF THE WEEK WITH A FEW
WEAK SHORTWAVES EMBEDDED IN THE FLOW. THE FIRST LOOKS TO BE ON
TUE/TUE NIGHT AND THE SECOND WED/WED NIGHT. EVAPORATIONAL COOLING
EFFECTS MAY RESULT IN A LIGHT SNOWFALL EVENT ON TUE...BUT IT
ATMOSPHERIC PROFILES LOOK WARMER FOR WED.
THE 12Z EC IS ALSO INDICATING THE POSSIBILITY OF A MORE SIGNIFICANT
STORM LATE NEXT WEEK. SOLUTIONS HAVE BEEN VARYING WITH THIS SYSTEM
FOR THE LAST FEW DAYS...SO HAVE KEPT IT DRY FOR NOW.
LONG TERM TEMPS ARE EXPECTED TO REMAIN ABOVE NORMAL EXCEPT FOR A
BRIEF COLD SNAP ON SUN WHERE TEMPS WILL BE AROUND 10 DEGREES BELOW
CLIMATOLOGICAL NORMS.
&&
.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
LOW PRES WILL PASS SE OF LONG ISLAND TODAY. LIGHT TO OCCASIONALLY
MODERATE SNOW WILL PRODUCE MVFR TO IFR CIGS/VSBYS OVER THE TERMINALS
INTO EARLY THIS AFTERNOON. CONDITIONS THEN IMPROVE TO VFR.
ARCTIC FRONT PASSES THROUGH THE REGION EARLY THIS EVENING. A BRIEF
PERIOD OF SNOW IS POSSIBLE WITH ITS PASSAGE...AND WILL INTRODUCE A
TEMPO GROUP AROUND ITS PASSAGE WITH THE 15Z TAF AMENDMENT PACKAGE TO
REFLECT THIS RISK.
AS THE LOW CONTINUES TO DEEPEN EAST OF THE AREA GUSTY NORTHWEST TO
NORTH WINDS WILL DEVELOP. SUSTAINED WINDS WILL BE AROUND 15 KT WITH
GUSTS UP TO 30 KT LIKELY...BEFORE INCREASING TO 20-25 KT WITH 30-35
KT GUSTS.
OUTLOOK FOR 15Z SUNDAY THROUGH WEDNESDAY...
SUNDAY...VFR. NW WINDS AROUND 310 TRUE AT 15-20 KT WITH 20-25 KT
GUSTS...BACKING TO THE LEFT OF 310 TRUE IN THE AFTERNOON.
SUNDAY NIGHT...VFR WITH DIMINISHING WEST WINDS.
MONDAY...VFR WITH GUSTY NW WINDS.
TUESDAY THROUGH WEDNESDAY...SUB VFR-POSSIBLE IN SCT LIGHT SNOW
TUESDAY AND RAIN AND SNOW WEDNESDAY.
&&
.MARINE...
SEAS RUNNING ABOUT A FOOT LOWER THAN FORECAST LEVELS...SO LOWERED
SEAS ON THE OCEAN WATERS A FOOT TO GET STARTED - BUT STILL A FOOT
ABOVE WAVEWATCH III GUIDANCE.
EXPECT QUIET CONDITIONS TODAY WITH MAINLY LIGHT
N-NE FLOW IN THE WAKE OF LOW PRES PASSING WELL TO THE SE.
TONIGHT...WINDS AND SEAS INCREASE. HAVE CONVERTED THE GALE WATCH TO
A GALE WARNING THE OCEAN WATERS. GUSTS TO 35 KT WILL BE LIKELY WITH
STRONG GUSTY WINDS ON COLD AIR ADVECTION. FOR THE REMAINDER OF THE
WATERS...HAVE HOISTED A SMALL CRAFT ADVISORY WHERE GUSTS WILL BE
LESS LIKELY. THERE DOES HOWEVER REMAIN A CHANCE THAT SOME GUSTS
REACH GALE FORCE. WINDS AND SEAS SLOWLY SUBSIDE ON MONDAY WITH SCA
CONDITIONS LIKELY THROUGH MON MORNING. OCEAN SEAS WILL TAKE LONGER
TO SUBSIDE...SO MAY NEED SCA THERE INTO MON NIGHT.
&&
.HYDROLOGY...
LIQUID EQUIVALENT QPF WITH THE ONGOING EVENT NOW LESS THAN 1/10
INCH NW OF NYC...AND 1/10 TO 1/4 INCH ELSEWHERE. NO SIGNIFICANT
PRECIPITATION EXPECTED EARLY NEXT WEEK.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 6 PM EST SUNDAY
FOR ANZ330-335-338-340-345.
GALE WARNING FROM 6 PM THIS EVENING TO 6 PM EST SUNDAY FOR
ANZ350-353-355.
&&
$$
SYNOPSIS...BC/GOODMAN
NEAR TERM...GOODMAN/MALOIT
SHORT TERM...GOODMAN
LONG TERM...GOODMAN/24
AVIATION...MPS
MARINE...BC/MALOIT
HYDROLOGY...GOODMAN
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
944 AM EST SAT FEB 11 2012
.SYNOPSIS...
A BROAD AREA OF LOW PRESSURE ALONG THE SOUTHERN MID ATLANTIC COAST
EARLY THIS MORNING WILL CONSOLIDATE AND DEEPEN AS IT MOVES NORTHEAST
AND OUT TO SEA TODAY, AND A COLD FRONT WILL CROSS OUR AREA THIS
AFTERNOON. THERE WILL BE A STRONG NORTHWEST FLOW AND SOME COLDER AIR
IN THE WAKE OF THE FRONT. A SECONDARY COLD FRONT WILL CROSS THE AREA
LATE SUNDAY. HIGH PRESSURE WILL BUILD IN ON MONDAY, THEN TWO WEAK
SYSTEMS COULD AFFECT THE REGION DURING THE MIDDLE TO LATTER PART OF
NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SOME BANDED FEATURES ARE STARTING TO APPEAR ON RADAR AS THE BEST
MID LEVEL FRONTOGENETIC CROSSES NEW JERSEY AT THIS TIME. THE
FEATURE APPEARS TO BE PROGRESSIVE. OTHERWISE...1200 UTC SOUNDINGS
ARE SHOWING MOIST CONDITIONS THROUGH THE MID LEVELS...WITHOUT MUCH
IN THE WAY OF FORCING THROUGH MID AFTERNOON TO REMOVE IT. THIS
PROBABLY MEANS LIGHT SNOW/RAIN MAY CONTINUE INTO THE EARLY
AFTERNOON...BUT LITTLE ADDITIONAL ACCUMULATION IS EXPECTED.
TEMPERATURES PROBABLY RISE JUST A COUPLE OF DEGREES...AS ANY
MEANINGFUL CLEARING LOOKS DOUBTFUL GIVEN THE AMOUNT OF MOISTURE IN
THE COLUMN.
CONDITIONS COULD BECOME ACTIVE LATE THIS AFTERNOON AND THIS
EVENING AS THE ARCTIC FRONT ACROSS EASTERN OHIO THIS MORNING
APPROACHES. MID LEVEL LAPSE RATES WILL STEEPEN (LAPSE RATES WERE
NEAR 7 C/KM ACROSS THE GREAT LAKES WITH THE SHORT WAVE PUSHING THE
FRONT ALONG). 500 MB TEMPERATURES WERE NEAR MINUS 36 CELSIUS IN
THE MID LEVELS...AND THE LOW LEVEL TEMPERATURE GRADIENT BETWEEN
KPBZ AND KDTX WAS VERY IMPRESSIVE.
THE LATEST HRRR SHOWS AN ALMOST SQUALL-LIKE STRUCTURE MOVING
THROUGH THE PENNSYLVANIA AND EASTERN MARYLAND BY ABOUT 2200 UTC.
GIVEN THE LAPSE RATES IN THE LOW AND MID LEVELS...THIS TYPE OF
STRUCTURE LOOKS POSSIBLE. A BURST OF SNOW IS POSSIBLE WITH THE
FRONT ITSELF...AND THIS POTENTIAL WILL BE ADDRESSED LATER THIS
MORNING AND THIS AFTERNOON.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SUNDAY/...
THE UPPER TROUGH WILL CROSS THE REGION TONIGHT. A SHARP SFC COLD
FRONT WILL CROSS THE AREA THIS EVENING. IT WILL BE ACCOMPANIED BY
GUSTY WINDS...FALLING TEMPERATURES AND SCATTERED SNOW SHOWERS. A
BETTER CHC FOR THE SNOW SHOWERS WILL BE ACROSS THE DELMARVA CLOSER
TO THE VORT MAX ALONG THE H5 TROUGH. HIGH CHC OR LOW LIKELY POPS
WILL BE OVER THE DELMARVA (AND CHESTER CTY PA) WHILE LOWER CHC POPS
WILL BE OVER THE REST OF PA AND NJ. TEMPERATURES WILL PLUNGE INTO
THE TEENS OVER THE POCONOS...LEHIGH VALLEY AND NRN NJ AND INTO THE
20S ELSEWHERE. WIND CHILL VALUES WILL BE IN THE SINGLE DIGITS WITH
SOME SUB-ZERO READINGS OVER THE SRN POCONOS. WINDS WILL GUST IN THE
25 TO 35 KT RANGE TONIGHT...ESPECIALLY OVER THE SRN COUNTIES.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
THE FAIRLY SHARP MID LEVEL TROUGH AXIS WILL DEVELOP A NEGATIVE
TILT AS IT LIFTS AWAY FROM OUR AREA ON SUNDAY, AND A SECONDARY
IMPULSE WILL DROP DOWN THE BACK SIDE OF IT AROUND SUNDAY EVENING.
SURFACE PRESSURE RISES IN THE WAKE OF THE TROUGH ARE ROBUST ENOUGH
TO FORECAST LAND WIND GUSTS IN EXCESS OF 30 MPH, BUT MODEL
SOUNDINGS AREN`T PRESENTLY SHOWING A WIND ADVISORY LEVEL FLOW. THE
SECONDARY IMPULSE ALSO CARRIES SOME LESSER PRESSURE RISES IN ITS
WAKE. THE SOUNDINGS ACROSS THE NORTH ARE CAPPED AT ABOUT 7000 FT
AND WE CARRY A CYCLONIC SURFACE FLOW SUNDAY INTO SUNDAY NIGHT, SO
WE CONTINUE TO CARRY FLURRIES NORTH DURING THIS TIME FRAME.
THE MODELS THEN AGREE TO TAKE A MID LEVEL IMPULSE ACROSS THE AREA IN
THE TUESDAY TO WEDNESDAY TIME FRAME, AND THEN START TO DIVERGE ON
THE HANDLING OF ANOTHER AND POSSIBLY MORE ROBUST SYSTEM TOWARD THE
END OF THE WORK WEEK. WE MADE MODEST CHANGES WITH RESPECT TO THE
FORMER AND FOLLOWED CONTINUITY WITH RESPECT TO THE LATTER.
TEMPERATURES WILL START OFF BELOW NORMAL EARLY THIS PERIOD,
TRANSITION TO NORMAL EARLY IN THE WORK WEEK AND THEN GO ABOVE
NORMAL FOR THE LATTER PART OF THE PERIOD.
&&
.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
THE LAST OF THE BANDED SNOW IS MOVING THROUGH THE KPHL METRO AREA
THIS MORNING...AND SHOULD CONTINUE TO SHRINK AS IT MOVES EAST.
THIS COULD RESULT IN LOCALLY IFR VISIBILITIES THROUGH ABOUT 1600
UTC. OTHERWISE...1200 UTC SOUNDINGS SHOW MOISTURE THROUGH THE MID
LEVELS...WITH LITTLE IN THE WAY OF PUSH TO SCOUR THE MOISTURE OUT.
WITH THIS IN MIND...THE TERMINAL FORECASTS WERE UPDATED TO INCLUDE
IFR CEILINGS FOR THROUGH ABOUT 1700 UTC. AFTER THIS...A SLOW
IMPROVEMENT IS POSSIBLE AS BOUNDARY LAYER WINDS INCREASE FROM THE
NORTH.
AN ARCTIC FRONT WILL CROSS THE AREA THIS EVENING. BASED ON WHAT IS
OCCURRING WITH THE FRONT ACROSS WESTERN PENNSYLVANIA...A SMALL
WINDOW (PERHAPS 2 HOURS) OF MVFR CONDITIONS WITH CEILINGS AND
VISIBILITIES IN SNOW SHOWERS IS POSSIBLE CENTERED AROUND 2300 UTC.
IN ADDITION...WINDS WILL SHIFT TO THE NORTHWEST AND COULD GUST TO
35 KNOTS DURING THE EVENING.
OUTLOOK...
OUTSIDE OF ANY SNOW SHOWER ACTIVITY THAT MAY OCCUR ON SUNDAY INTO
SUNDAY EVENING (ESPECIALLY NORTHWEST), WE EXPECT VFR CONDITIONS INTO
TUESDAY. THE WEAK WEATHER SYSTEM DURING THE MIDWEEK PERIOD MAY CAUSE
SOME DETERIORATION IN CONDITIONS.
&&
.MARINE...
WE WILL CONVERT THE GALE WATCH TO A WARNING AND EXTEND IT OUT UNTIL
06Z MONDAY.
LOW PRESSURE WILL DEEPEN OFF THE EAST COAST AND TRACK WELL TO OUR
EAST TODAY THROUGH SUNDAY. THE GRADIENT OVER THE WATERS WILL NOT BE
VERY STRONG TODAY...BUT WILL STRENGTHEN SIGNIFICANTLY LATER TODAY
AND REMAIN STRONG INTO EARLY NEXT WEEK. A COLD FRONT WILL CROSS THE
WATERS THIS EVENING AND THE STRONG WIND GUSTS WILL FOLLOW IT. GUSTS
TO 40 KTS ARE POSSIBLE. SCATTERED SNOW SHOWERS WITH LOWER VSBYS MAY
ACCOMPANY THE FRONT. GUSTY WINDS AND ENHANCED SEAS WILL CONTINUE
THROUGH TONIGHT.
GALES ARE EXPECTED TO LAST INTO SUNDAY, AND THEY MAY LINGER INTO
SUNDAY EVENING WITH A SECONDARY FRONT CROSSING THE AREA. AFTER
THAT, CONDITIONS SHOULD DROP TO SUB-ADVISORY AND REMAIN SO THROUGH
THE MIDDLE OF THE WEEK.
&&
.TIDES/COASTAL FLOODING...
NONE OF THE LATEST OFS PROGS ARE TAKING ANY OF THE REFERENCE GAUGES
TO WITHIN A HALF FOOT OF THE MINOR TIDAL FLOODING BENCHMARKS. NO
DEPARTURES THIS MORNING WERE MUCH IN EXCESS OF 0.5 FT. WE WILL
CONTINUE TO MONITOR TIDES IN THE EVENT THAT THE PROGS ARE UNDERDONE,
BUT ANY THREAT OF MINOR TIDAL FLOODING WILL DIMINISH ONCE WINDS COME
AROUND TO NORTHWEST. WE THEN WILL TURN OUR CONCERN TO THE POSSIBILITY
OF BLOWOUT TIDES, WHICH ALSO IS DOWNPLAYED BY OFS PROGS.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...GALE WARNING FROM 6 PM THIS EVENING TO 1 AM EST MONDAY FOR
ANZ430-431-450>455.
&&
$$
SYNOPSIS...DELISI
NEAR TERM...HAYES
SHORT TERM...O`HARA
LONG TERM...DELISI/KRUZDLO
AVIATION...DELISI/HAYES
MARINE...DELISI/O`HARA
TIDES/COASTAL FLOODING...DELISI
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
856 AM EST SAT FEB 11 2012
.SYNOPSIS...
A BROAD AREA OF LOW PRESSURE ALONG THE SOUTHERN MID ATLANTIC COAST
EARLY THIS MORNING WILL CONSOLIDATE AND DEEPEN AS IT MOVES NORTHEAST
AND OUT TO SEA TODAY, AND A COLD FRONT WILL CROSS OUR AREA THIS
AFTERNOON. THERE WILL BE A STRONG NORTHWEST FLOW AND SOME COLDER AIR
IN THE WAKE OF THE FRONT. A SECONDARY COLD FRONT WILL CROSS THE AREA
LATE SUNDAY. HIGH PRESSURE WILL BUILD IN ON MONDAY, THEN TWO WEAK
SYSTEMS COULD AFFECT THE REGION DURING THE MIDDLE TO LATTER PART OF
NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SOME BANDED FEATURES ARE STARTING TO APPEAR ON RADAR AS THE BEST
MID LEVEL FRONTOGENETIC CROSSES NEW JERSEY AT THIS TIME. THE
FEATURE APPEARS TO BE PROGRESSIVE...SO UNLESS IT SLOWS DOWN THE
WINTER WEATHER ADVISORY WILL BE ALLOWED TO EXPIRE ON TIME OR
CANCELED AT THE NEXT FORECAST UPDATE.
OTHERWISE...1200 UTC SOUNDINGS ARE SHOWING MOIST CONDITIONS
THROUGH THE MID LEVELS...WITHOUT MUCH IN THE WAY OF FORCING
THROUGH MID AFTERNOON TO REMOVE IT. THIS PROBABLY MEANS LIGHT
SNOW/RAIN MAY CONTINUE INTO THE EARLY AFTERNOON...BUT LITTLE
ADDITIONAL ACCUMULATION IS EXPECTED. TEMPERATURES PROBABLY RISE
JUST A COUPLE OF DEGREES...AS ANY MEANINGFUL CLEARING LOOKS
DOUBTFUL GIVEN THE AMOUNT OF MOISTURE IN THE COLUMN.
CONDITIONS COULD BECOME ACTIVE LATE THIS AFTERNOON AND THIS
EVENING AS THE ARCTIC FRONT ACROSS EASTERN OHIO THIS MORNING
APPROACHES. MID LEVEL LAPSE RATES WILL STEEPEN (LAPSE RATES WERE
NEAR 7 C/KM ACROSS THE GREAT LAKES WITH THE SHORT WAVE PUSHING THE
FRONT ALONG). 500 MB TEMPERATURES WERE NEAR MINUS 36 CELSIUS IN
THE MID LEVELS...AND THE LOW LEVEL TEMPERATURE GRADIENT BETWEEN
KPBZ AND KDTX WAS VERY IMPRESSIVE.
THE LATEST HRRR SHOWS AN ALMOST SQUALL-LIKE STRUCTURE MOVING
THROUGH THE PENNSYLVANIA AND EASTERN MARYLAND BY ABOUT 2200 UTC.
GIVEN THE LAPSE RATES IN THE LOW AND MID LEVELS...THIS TYPE OF
STRUCTURE LOOKS POSSIBLE. A BURST OF SNOW IS POSSIBLE WITH THE
FRONT ITSELF...AND THIS POTENTIAL WILL BE ADDRESSED LATER THIS
MORNING AND THIS AFTERNOON.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SUNDAY/...
THE UPPER TROUGH WILL CROSS THE REGION TONIGHT. A SHARP SFC COLD
FRONT WILL CROSS THE AREA THIS EVENING. IT WILL BE ACCOMPANIED BY
GUSTY WINDS...FALLING TEMPERATURES AND SCATTERED SNOW SHOWERS. A
BETTER CHC FOR THE SNOW SHOWERS WILL BE ACROSS THE DELMARVA CLOSER
TO THE VORT MAX ALONG THE H5 TROUGH. HIGH CHC OR LOW LIKELY POPS
WILL BE OVER THE DELMARVA (AND CHESTER CTY PA) WHILE LOWER CHC POPS
WILL BE OVER THE REST OF PA AND NJ. TEMPERATURES WILL PLUNGE INTO
THE TEENS OVER THE POCONOS...LEHIGH VALLEY AND NRN NJ AND INTO THE
20S ELSEWHERE. WIND CHILL VALUES WILL BE IN THE SINGLE DIGITS WITH
SOME SUB-ZERO READINGS OVER THE SRN POCONOS. WINDS WILL GUST IN THE
25 TO 35 KT RANGE TONIGHT...ESPECIALLY OVER THE SRN COUNTIES.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
THE FAIRLY SHARP MID LEVEL TROUGH AXIS WILL DEVELOP A NEGATIVE
TILT AS IT LIFTS AWAY FROM OUR AREA ON SUNDAY, AND A SECONDARY
IMPULSE WILL DROP DOWN THE BACK SIDE OF IT AROUND SUNDAY EVENING.
SURFACE PRESSURE RISES IN THE WAKE OF THE TROUGH ARE ROBUST ENOUGH
TO FORECAST LAND WIND GUSTS IN EXCESS OF 30 MPH, BUT MODEL
SOUNDINGS AREN`T PRESENTLY SHOWING A WIND ADVISORY LEVEL FLOW. THE
SECONDARY IMPULSE ALSO CARRIES SOME LESSER PRESSURE RISES IN ITS
WAKE. THE SOUNDINGS ACROSS THE NORTH ARE CAPPED AT ABOUT 7000 FT
AND WE CARRY A CYCLONIC SURFACE FLOW SUNDAY INTO SUNDAY NIGHT, SO
WE CONTINUE TO CARRY FLURRIES NORTH DURING THIS TIME FRAME.
THE MODELS THEN AGREE TO TAKE A MID LEVEL IMPULSE ACROSS THE AREA IN
THE TUESDAY TO WEDNESDAY TIME FRAME, AND THEN START TO DIVERGE ON
THE HANDLING OF ANOTHER AND POSSIBLY MORE ROBUST SYSTEM TOWARD THE
END OF THE WORK WEEK. WE MADE MODEST CHANGES WITH RESPECT TO THE
FORMER AND FOLLOWED CONTINUITY WITH RESPECT TO THE LATTER.
TEMPERATURES WILL START OFF BELOW NORMAL EARLY THIS PERIOD,
TRANSITION TO NORMAL EARLY IN THE WORK WEEK AND THEN GO ABOVE
NORMAL FOR THE LATTER PART OF THE PERIOD.
&&
.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
LOW CIGS/VSBYS IN SNOW CONTINUE AT THE TERMINALS EARLY THIS MORNING.
AVIATION CONDITIONS WILL START TO IMPROVE BY THE MID-MORNING...LOW
CONFID IN WHETHER CONDITIONS TODAY WILL GET BACK TO VFR OR REMAIN
MVFR. 12Z TAFS MAY INCORPORATE CHANGES TO THE ONGOING TERMINALS. SKY
COVER WILL BE BKN-OVC TODAY WITH MOST OF THE PRECIPITATION ENDING
BEFORE NOON. A SHARP COLD FRONT CROSSES THE TERMINALS THIS EVENING
WITH WINDS SHIFTING NW AND INCREASING WITH 25-30 KT GUSTS OVERNIGHT.
SCATTERED SNOW SHOWERS AND BRIEFLY LOWER CIGS MAY ACCOMPANY THE
FRONT. VFR CONDITIONS WILL RETURN BEHIND THE FRONT.
OUTLOOK...
OUTSIDE OF ANY SNOW SHOWER ACTIVITY THAT MAY OCCUR ON SUNDAY INTO
SUNDAY EVENING (ESPECIALLY NORTHWEST), WE EXPECT VFR CONDITIONS INTO
TUESDAY. THE WEAK WEATHER SYSTEM DURING THE MIDWEEK PERIOD MAY CAUSE
SOME DETERIORATION IN CONDITIONS.
&&
.MARINE...
WE WILL CONVERT THE GALE WATCH TO A WARNING AND EXTEND IT OUT UNTIL
06Z MONDAY.
LOW PRESSURE WILL DEEPEN OFF THE EAST COAST AND TRACK WELL TO OUR
EAST TODAY THROUGH SUNDAY. THE GRADIENT OVER THE WATERS WILL NOT BE
VERY STRONG TODAY...BUT WILL STRENGTHEN SIGNIFICANTLY LATER TODAY
AND REMAIN STRONG INTO EARLY NEXT WEEK. A COLD FRONT WILL CROSS THE
WATERS THIS EVENING AND THE STRONG WIND GUSTS WILL FOLLOW IT. GUSTS
TO 40 KTS ARE POSSIBLE. SCATTERED SNOW SHOWERS WITH LOWER VSBYS MAY
ACCOMPANY THE FRONT. GUSTY WINDS AND ENHANCED SEAS WILL CONTINUE
THROUGH TONIGHT.
GALES ARE EXPECTED TO LAST INTO SUNDAY, AND THEY MAY LINGER INTO
SUNDAY EVENING WITH A SECONDARY FRONT CROSSING THE AREA. AFTER
THAT, CONDITIONS SHOULD DROP TO SUB-ADVISORY AND REMAIN SO THROUGH
THE MIDDLE OF THE WEEK.
&&
.TIDES/COASTAL FLOODING...
NONE OF THE LATEST OFS PROGS ARE TAKING ANY OF THE REFERENCE GAUGES
TO WITHIN A HALF FOOT OF THE MINOR TIDAL FLOODING BENCHMARKS. NO
DEPARTURES THIS MORNING WERE MUCH IN EXCESS OF 0.5 FT. WE WILL
CONTINUE TO MONITOR TIDES IN THE EVENT THAT THE PROGS ARE UNDERDONE,
BUT ANY THREAT OF MINOR TIDAL FLOODING WILL DIMINISH ONCE WINDS COME
AROUND TO NORTHWEST. WE THEN WILL TURN OUR CONCERN TO THE POSSIBILITY
OF BLOWOUT TIDES, WHICH ALSO IS DOWNPLAYED BY OFS PROGS.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR
PAZ070-071.
NJ...WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR
NJZ016>020-027.
DE...WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR
DEZ001.
MD...WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR
MDZ008.
MARINE...GALE WARNING FROM 6 PM THIS EVENING TO 1 AM EST MONDAY FOR
ANZ430-431-450>455.
&&
$$
SYNOPSIS...DELISI
NEAR TERM...HAYES
SHORT TERM...O`HARA
LONG TERM...DELISI/KRUZDLO
AVIATION...DELISI/O`HARA
MARINE...DELISI/O`HARA
TIDES/COASTAL FLOODING...DELISI
AREA FORECAST DISCUSSION
NWS LINCOLN IL
525 AM CST SAT FEB 11 2012
.DISCUSSION...
ISSUED 322 AM CST SAT FEB 11 2012
COLD AIR MOVING INTO THE REGION BEHIND A FRONTAL SYSTEM AND A DEEP
UPPER TROF...FINALLY BRINGING SOME COLDER AND MORE SEASONABLE TEMPS
INTO THE MIDWEST FOR THE WEEKEND. HIGH PRESSURE BUILDING IN OVER
THE NRN PLAINS...AND CLEARING SKIES SCOURING OUT THE REMNANT
FLURRIES OVER ILX. MAIN ISSUES FOR THE FORECAST REVOLVE AROUND THE
NEXT SYSTEM ON APPROACH FOR MON/TUES. SOME MINOR TIMING ISSUES
AFFECT THE ONSET OF SNOW ON MONDAY...BUT THE ABUNDANCE OF COLD AIR HAS
EFFECTIVELY REMOVED MOST CONCERNS ABOUT PRECIP TYPE. FORECAST
REMAINS A SLIGHT BLEND...BUT MOST OF THE PARAMETERS ARE IN
RELATIVE AGREEMENT. NEXT ISSUES IN THE FORECAST WILL BE THE TEMPS
ON THE OTHER SIDE OF THE SNOW AT THE END OF THE WORK WEEK. MOS
NUMBERS LOOK A LITTLE TOO WARM CONSIDERING ANOTHER SHOT OF COLD
AIR MOVING IN AT MID LEVELS.
SHORT TERM...TODAY AND TOMORROW...
COLD. TEMPS CHILLY THIS MORNING IN THE TEENS ACROSS CENTRAL
ILLINOIS...AND BRISK NORTHERLY FLOW WILL KEEP THE HIGHS
CONSIDERABLY COOLER...HIGHS ONLY CLIMBING INTO THE
20S...REGARDLESS OF AMPLE SUNSHINE. SAME CONTINUES TONIGHT...WITH
CLEAR SKIES AND AN ARCTIC AIRMASS PUSHING THE TEMPS DOWN INTO THE
SINGLE DIGITS AND AROUND 10F. HIGH PRESSURE RIDGE SHIFTS ENOUGH TO
BRING WINDS TO A MORE WESTERLY DIRECTION FOR TOMORROW...AND TEMPS
WILL CLIMB BACK UP TO UPPER 20S...AND DROP INTO THE TEENS SUN
NIGHT IN ADVANCE OF THE CLOUDS ASSOCIATED WITH THE NEXT DEVELOPING
SYSTEM MOVING OUT OF THE WEST.
LONG TERM...MONDAY THROUGH FRIDAY...
WAVE MOVING INTO THE PAC NW WILL PUSH OVER THE ROCKIES AND INTO
THE MIDWEST MID-MONDAY AND BRING THE NEXT CHANCE FOR SNOW. MODELS
IN ENOUGH ARGUMENT TO GO CATEGORICAL AT THIS POINT...WITH THE GFS
JUST SLIGHTLY AHEAD...BRINGING IN THE SNOW ACROSS THE WRN HALF OF
THE CWA BY NOON. BETTER CHANCES STILL LATER MONDAY AFTERNOON AND
MON EVENING INTO THE OVERNIGHT. HPC AND PREV FORECAST RATHER
CONSISTENT IN THE 1 TO 2 INCH STORM TOTALS. SLR AROUND 13
CONSISTENT WITH CLIMATOLOGY...AND FORECAST SOUNDINGS ACROSS THE
BOARD SHOWING PLENTY OF MOISTURE TO WORK WITH THROUGHOUT THE
COLUMN MON LATE AFTERNOON. SNOW TAPERING OFF DURING THE DAY ON
TUESDAY. ANOTHER SYSTEM QUICK ON ITS HEELS MOVING OUT OF THE
ROCKIES EARLY THU. CURIOUS AGREEMENT IN THE EXTENDED BTWN THE GFS
AND THE ECMWF...AND POPS WILL COME UP IF THE AGREEMENT
CONTINUES...EVEN AT DAY 6. HOWEVER...THE TRACK OF THE GFS IS A BIT
FURTHER SOUTH WHICH WOULD MAKE A RATHER SIG DIFFERENCE FOR AREAS
NORTH OF ILLINOIS RIVER VALLEY AS FAR AS IMPACT. TEMPS FOR THU AND
FRI A BIT WARM AT THIS POINT. CONCERNED THAT THE ECMWF IS BRINGING
THROUGH SOME RATHER COLD AIR AT MID LEVELS AND PLENTY OF
CLOUDS...NOT CONVINCED THAT THE SFC TEMPS WILL GET THAT WARM AND
HAVE PULLED THEM DOWN SLIGHTLY. THIS MISREPRESENTATION WILL DEF
HAVE IMPACT ON THE PRECIP TYPE. NOT SUPER CONFIDENT JUST YET IN
THE EXTENDED.
&&
.AVIATION...
ISSUED 525 AM CST SAT FEB 11 2012
STRONG HIGH PRESSURE CENTERED IN SOUTH DAKOTA WILL BE THE MAIN
WEATHER INFLUENCE IN CENTRAL AND EASTERN IL TODAY AND SUNDAY.
PLENTY OF SUBSIDENCE AND DRY AIR WILL RESULT IN VFR CONDITIONS THE
NEXT 24 HOURS. WILL GO WITH A CLEAR SKY AT ALL TAF SITES AS A
RESULT. THE RUC WAS TRYING TO INDICATE SOME SCT-BKN CU NEAR KCMI
AND POINTS EAST FROM LAKE MICHIGAN LATE THIS MORNING. HOWEVER THE
FETCH DOWN THE LAKE SHOULD BECOME MORE NORTH-NORTHWESTERLY...WHICH
WOULD KEEP ANY CLOUDS EAST OF THE AREA.
THE WIND HAS RELAXED A LITTLE BIT IN PARTS OF CENTRAL IL EARLY
THIS MORNING...DESPITE A CONTINUED TIGHT PRESSURE GRADIENT. I
EXPECT THIS TO INCREASE AGAIN BY LATE MORNING AS THE LOWER
ATMOSPHERE STARTS TO MIX. BUFKIT SOUNDINGS AND MOMENTUM TRANSFER
POINT TO GUSTS IN THE 20-28KT RANGE TODAY...SO WILL FOLLOW THAT
GUIDANCE CLOSELY.
MILLER
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
650 AM EST SAT FEB 11 2012
.AVIATION...
12Z TAFS...LAKE EFFECT SNOW EVENT ALREADY UNDERWAY ACROSS NORTHERN
INDIANA WILL BE THE MAIN FOCUS FOR THE AVIATION FORECAST. BACKING
OF LARGER SCALE LOW LEVEL WIND FLOW HAS TAKEN MAIN LAKE EFFECT
BAND ACROSS EASTERN LAKE MICHIGAN INTO NORTHWEST INDIANA THIS
MORNING. THE COMBINATION OF HEAVIER BURSTS OF SNOW WITH GUSTY
NORTH WINDS/BLSN WILL RESULT IN VSBYS DROPPING TO A HALF MILE OR LESS
AT TIMES THROUGH 15Z OR 16Z AT KSBN. AFTER 16Z...INVERSION HEIGHTS
SHOULD BEGIN TO DROP MORE STEADILY...WHICH LOWERS THE CONFIDENCE
IN SNOW RATES AFTER THIS TIME. OVERALL...NOT MUCH CHANGE TO THE
06Z TAFS WITH RESPECT TO PERIOD OF HEAVIEST SNOW AT KSBN FROM 12Z
TO 16Z. WINDS HAVE TEMPORARILY SUBSIDED AT KSBN IN ASSOCIATION
WITH LAKE INDUCED CONVERGENCE AXIS...BUT EXPECTING GUSTS BACK
CLOSE TO 25 KNOTS BY MID MORNING WITH INCREASING MIXING. LOW LEVEL
TRAJECTORIES WILL SUPPORT CONTINUED SCT SNOW SHOWERS INTO THE
AFTERNOON...WITH A PERIOD OF SOME SCT SNOW SHOWERS AND FLURRIES
POSSIBLE AT KFWA LATE MORNING THROUGH MID AFTERNOON. MVFR
CONDITIONS THIS AFTERNOON SHOULD TREND TO VFR THIS EVENING AS
DRIER LOW LEVEL AIR ADVECTS SOUTHEASTWARD.
&&
.PREV DISCUSSION... /ISSUED 423 AM EST SAT FEB 11 2012/
SHORT TERM.../TODAY THROUGH SUNDAY NIGHT/
..LAKE EFFECT SNOW EVENT UNDERWAY...
ARCTIC COLD FRONT HAS SWEPT ACROSS THE FORECAST AREA WITH
TEMPERATURES IN THE TEENS AND DEWPTS FALLING INTO THE SINGLE DIGITS.
SOME LEFTOVER LIGHT SNOW WAS SEEN ON OBS AND RADAR ACROSS PORTIONS
OF NORTHEASTERN INDIANA AND NORTHWESTERN OHIO. MAIN FOCUS WAS WELL
DEFINED INTENSE LAKE EFFECT SNOW BAND THAT RAPIDLY DEVELOPED ACROSS
LAKE AND PORTER COUNTIES THIS PAST EVENING AND AFTER A BRIEF SHIFT
WEST AND INCREASE IN EASTERN PROGRESS HAS BEEN NOTED WITH THE BAND
CURRENTLY SITUATED ACROSS LAPORTE AND STARKE COUNTIES AHEAD OF
SCHEDULE. REPORT FROM VALPO UNIV OF LIGHTNING WAS RECEIVED AS THE
HEAVIEST PART OF THE BAND SHIFTED ACROSS THAT AREA. RADAR TRENDS
ACROSS THE FORECAST AREA HAS SHOWN A DOWNWARD TREND IN SOUTHERN
EXTENT AND INTENSITY OF THE BAND. UPSTREAM ACROSS THE LAKE KGRR
RADAR SHOWING AN INCREASE IN RETURNS AS THE BAND SHIFTED MORE ALONG
THE EASTERN SHORE OF THE LAKE. A FEW RUNS OF THE HRRR SUGGESTED THIS
MAY OCCUR WITH THE INITIAL BAND WEAKENING WITH TIME AS CONVERGENCE
WEAKENED AND MORE OF A MULTI BAND SETUP BEGAN TO ESTABLISH WITH TIME
THIS MORNING. WHILE FULL WARNING CRITERIA MAY NOT BE
MET...DETERIORATING CONDITIONS STILL WARRANT HOLDING ONTO CURRENT
HEADLINES. RISK FOR WARNING CRITERIA STILL POSSIBLE OVER BERRIEN
COUNTY AS BAND REORIENTS AND PERSISTS INTO EARLY AFTERNOON. DID
EXPAND POPS FURTHER SOUTH AND EAST AS INLAND EXTENT OF BANDS MAY
INCREASE AS OVERALL FLOW INCREASES SOMEWHAT WITH STRONGER GRADIENT
SHIFTING ACROSS THE AREA. WOULD NOT EXPECT MUCH IMPACT BUT FELT AT
LEAST CHC POPS WERE NEEDED DOWNSTREAM OF THE BAND.
GIVEN UNCERTAINTY OF EXTENT AND INTENSITY OF HEAVIEST BANDS HAVE
WENT WITH LIKELY POPS INTO THE AFTERNOON WITH ONLY LIGHT ADDITIONAL
ACCUMS.
NW FLOW WILL PERSIST ACROSS THE REGION INTO SUNDAY. HOWEVER...LL
TEMPS WILL QUICKLY UNDERGO MODERATION TONIGHT INTO SUNDAY CAUSING
DELTA T`S TO DECREASE AND INVERSION HGTS TO LOWER. THE RESULT WILL
BE SOME LINGERING VERY LIGHT SNOW OR FLURRIES INTO TONIGHT BEFORE
ENDING. SUNDAY/SUNDAY NIGHT APPEAR DRY AT THIS POINT WITH HIGH
PRESSURE BUILDING IN. MEAN RH VALUES DROPS CONSIDERABLY BY SUNDAY
AFTERNOON INTO SUNDAY NIGHT...ALLOWING FOR MOSTLY CLEAR TO CLEAR
SKIES AND MODERATING TEMPS.
&&
LONG TERM...MONDAY THROUGH FRIDAY
OVERALL VERY FEW CHANGES REQUIRED TO THE LONG TERM PERIOD FOR THIS
FORECAST CYCLE.
FOR MONDAY...LOW LEVEL ANTICYCLONE WILL SHIFT EASTWARD THROUGH THE
LOWER MS RIVER VALLEY INTO THE SOUTHEAST US...EVENTUALLY ALLOWING
LOW LEVEL RETURN SOUTHWESTERLY FLOW TO SETUP. A SHEARED UPPER VORT
MAX DIVORCED FROM STRONGER STEERING FLOW AS A RESULT OF WESTERN
CONUS SPLIT FLOW SHOULD GRADUALLY GET PHASED WITH A MORE AMPLIFIED
SOUTHERN STREAM TROUGH KICKING OUT OF THE FOUR CORNERS REGION. AS
THIS OCCURS...STRONGER LOW LEVEL THETAE ADVECTION/ISENTROPIC LIFT
SHOULD BE FOCUSED JUST WEST OF THE AREA. NAM/GFS ISENTROPIC PROGS IN
290-280K LAYER DO INDICATE MORE SUBSTANTIAL LOWERING OF
CONDENSATIONAL PRESSURE DEFICITS THROUGHOUT THIS LAYER BY LATE IN
THE DAY MONDAY...BUT SUBCLOUD LAYER MAY BE TOO DRY FOR MOST AREAS TO
RECEIVE ANY PRECIP MONDAY AFTERNOON. A SHARP LOW LEVEL GRADIENT
NOTED IN MIXING RATIOS THROUGHOUT THIS LAYER FROM WEST TO EAST ON
MONDAY...AND PREVIOUS POP GRADIENT MONDAY AFTERNOON FROM LOW CHANCE
WEST TO SLIGHT CHANCE EAST STILL APPEARS REASONABLE. STRONGER
ISENTROPIC UPGLIDE AND MID LEVEL FORCING TO MOVE IN FOR MONDAY NIGHT
WHICH STILL APPEARS TO BE SHAPING UP AS A HIGH POP/LOW QPF EVENT
BASED ON A RELATIVELY SHORT DURATION OF BETTER LOW/MID LEVEL
MOISTURE PROFILES AND RATHER DISJOINTED NATURE OF MID/UPPER LEVEL
FORCING WITH ONLY PARTIAL PHASING OF THESE AFOREMENTIONED SHORT
WAVES. MOST OF PRECIP EXPECTED MONDAY NIGHT BUT WILL CONTINUE TO
CARRY CHANCE -SN MENTION INTO TUESDAY WITH LAGGING SHORT WAVE SLOW
TO EXIT THE AREA. PRECIP MAY END AS A PERIOD OF DRIZZLE/FLURRIES
TUESDAY NIGHT...ESPECIALLY ACROSS EASTERN AREAS...AS MOISTURE
PROFILES BECOMING INCREASING SHALLOW WITH ONLY WEAK MID LEVEL
FORCING.
MEDIUM RANGE MODELS HAVE STARTED TO CONVERGE A BIT MORE IN REGARDS
TO MID/LATE WEEK SYSTEM WITH ECMWF EXHIBITING SOME BETTER RUN TO RUN
CONTINUITY IN COMPARISON TO 24 HOURS AGO. FLOW PATTERN QUITE COMPLEX
FOR THIS PERIOD WITH MAIN QUESTION REGARDING PHASING ISSUES OF NEXT
SOUTHERN STEAM UPPER TROUGH WITH ACTIVE SOUTHERN CANADIAN NORTHERN
STREAM. GENERALLY FOLLOWED HPC PREFERENCE OF A SLIGHTLY SLOWER THAN
ECMWF SOLUTION GIVEN EXPECTED FAST BIASED EJECTION OF SOUTHWEST US
WAVE. THIS CENTERS HIGHEST POPS IN THE THURS NIGHT PERIOD BUT
DEPENDING ON RATE OF EJECTION OF THIS TROUGH...PRECIP MAY EVENTUALLY
HAVE TO BE ADDED INTO FRIDAY. HARD TO DEVIATE AT THIS TIME FROM A
BROADBRUSH RAIN/SNOW PTYPE MENTION FOR THURSDAY/THURSDAY NIGHT GIVEN
EXPECTED MARGINAL LOW LEVEL THERMAL PROFILES DURING THIS PERIOD.
TEMPS SHOULD TREND SLIGHTLY ABOVE SEASONABLE NORMS FOR THE WED-FRI
PERIOD WITH SOME SUGGESTIONS OF A BRIEF SHOT OF COLD ADVECTION
TOWARD THE END OF THE PERIOD AS LARGER SCALE NORTHERN STREAM TROUGH
DIGS ACROSS THE GREAT LAKES REGION.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...WINTER STORM WARNING UNTIL 10 AM CST THIS MORNING FOR INZ003-012.
WINTER WEATHER ADVISORY UNTIL 11 AM EST THIS MORNING FOR INZ013.
WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS EVENING FOR INZ004-
014.
MI...WINTER STORM WARNING UNTIL 6 PM EST THIS EVENING FOR MIZ077.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 7 AM EST MONDAY FOR LMZ043.
SMALL CRAFT ADVISORY FROM 11 AM THIS MORNING TO 7 AM EST MONDAY
FOR LMZ046.
GALE WARNING UNTIL 11 AM EST THIS MORNING FOR LMZ046.
&&
$$
SHORT TERM...FISHER
LONG TERM...MARSILI
AVIATION...MARSILI
AREA FORECAST DISCUSSION
NWS GOODLAND KS
434 AM MST SAT FEB 11 2012
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 231 AM MST SAT FEB 11 2012
04Z WATER VAPOR IMAGERY INDICATED SHORT WAVE RIDGING ACROSS THE
CENTRAL ROCKIES...WITH CWA ON WESTERN PERIPHERY OF LONG WAVE
TROUGH. PV FIELDS INDICATED SHORT WAVE TROUGH ACROSS MONTANA
MOVING TO THE SOUTHEAST. AT THE SFC...1043MB SFC HIGH WAS BUILDING
INTO THE PLAINS WITH COLD TEMPERATURES ALREADY OCCURRING NEAR THE
CENTER IN SOUTH DAKOTA...WITH AREA OF LIGHT SNOW AND FOG ALONG
WESTERN FLANK OF SFC HIGH ACROSS NW CWA.
MAIN FORECAST CONCERNS WILL BE COVERAGE/INTENSITY/AMOUNTS OF SNOW
THIS MORNING FOLLOWED BY TEMPS THROUGH SUNDAY MORNING.
TODAY-TONIGHT...AREA OF LIGHT TO OCCASIONALLY MODERATE SNOW WILL
CONTINUE THROUGH THE MORNING HOURS...JUST TO THE SOUTH OF STRONG
AREA OF H7-H6 FRONTOGENESIS. GIVEN THE HIGH SNOW TO LIQUID RATIOS
ALREADY OBSERVED (AROUND 20 TO 1 AT GLD AT 6Z) AND POTENTIAL FOR AT
LEAST A FEW STRONGER BANDS GIVEN INSTABILITY PROFILE...EXPECT A SPOT
OR TWO TO SEE A LITTLE OVER 3 INCHES BEFORE SNOW ENDS...AS LAW
ENFORCEMENT REPORTS 1-2 INCHES OF SNOW HAS FALLEN THROUGH 9Z. WITH
SHORT WAVE RIDGE SHIFTING TO THE EAST DURING THE MORNING
HOURS...STATIC STABILITY INCREASING AND FRONTOGENESIS AND JET STREAK
SUPPORT DECREASING THROUGH THE MORNING HOURS EXPECT PRECIPITATION TO
WEAKEN THROUGH THE MORNING HOURS WITH PRECIPITATION CHANCES
DECREASING THROUGH 18Z...AND THINK ANY KIND OF SNOW ADVISORY NOW
WOULD LIKELY BE TOO SHORT LIVED TO BE WORTH WHILE. WITH SNOW
DIMINISHING EXPECT QUIET WEATHER THROUGH THE AFTERNOON AND
EVENING...BUT WITH STRONG WAA EXPECTED TO REDEVELOP OVERNIGHT SOME
ADVECTION FOG/PATCHY FREEZING DRIZZLE STILL POSSIBLE ALTHOUGH LATEST
VERTICAL PROFILES WILL KEEP PROBABILITIES FAIRLY LOW. WITH SFC
RIDGE...CLOUD COVER AND FRESH SNOW COVER THINK TEMPS WILL STRUGGLE
TO CLIMB BACK INTO THE TEENS IN SOME LOCATIONS AND DEPENDING ON THE
STRENGTH OF CAA THE NEXT FEW HOURS...MAY HAVE WIND CHILL ADVISORY
CONDITIONS IN EASTERN CWA.
SUNDAY-MONDAY...SHORT WAVE RIDGE WILL CONTINUE TO SHIFT TO THE EAST
THROUGH THE DAY SUNDAY MORNING AS ANOTHER SHORT WAVE TROUGH MOVES
INTO THE FOUR CORNERS AREA...BEFORE BEGINNING TO LIFT OUT ACROSS THE
PLAINS BY SUNDAY NIGHT. MID LEVEL LAPSE RATES SUGGEST ATMOSPHERE
WILL BE POTENTIALLY UNSTABLE SUNDAY AFTERNOON THROUGH THE
EVENING...BUT AM GOING TO SIDE WITH GEFS POPS FOR THE AFTERNOON
PERIODS AND HOLD OFF ON ANY MEANINGFUL PRECIP CHANCES UNTIL THE
EVENING...WHEN LARGE SCALE FORCING FOR ASCENT AND POTENTIAL
INSTABILITY BETTER ALIGNED. AM A LITTLE MORE CONFIDENT ABOUT PRECIP
POTENTIAL THIS PERIOD...BUT WITH SOME MODELS INDICATING A PRONOUNCED
DRY SLOT AM GOING TO HOLD THINGS IN THE CHANCE RANGE FOR NOW. WHILE
SOUNDINGS SUGGEST A WARM LAYER WILL BE PRESENT THAT COULD
POTENTIALLY CREATE SOME MIXED PHASE ISSUES...WETBULB PROFILES
CONTINUE TO SUGGEST ALL SNOW AND PLAN ON LEAVING PTYPES THAT WAY FOR
THE TIME BEING. SYSTEM SHOULD QUICKLY MOVE TO THE EAST MONDAY
MORNING AND WHILE SOME LIGHT PRECIPITATION POSSIBLE EARLY...WITH
DOWNWARD MOTION QUICKLY OVERSPREADING THE AREA AND POTENTIAL DRY
SLOT NEARBY DO NOT THINK CHANCES WILL BE AS GOOD AS OVERNIGHT
SUNDAY. DID NOT MAKE A LOT OF CHANGES TO CURRENT FORECAST FOR
TEMPS...BUT DID WARM THINGS UP A FEW DEGREES AS APPROACHING SYSTEM
WILL LIKELY SHIFT COLDER AIR MASS EAST AWAY FROM THE AREA.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 231 AM MST SAT FEB 11 2012
WITH AN UPPER LEVEL RIDGE OVER THE TRI-STATE AREA TUESDAY...FOCUS
FOR THIS PERIOD WILL BE THE STORM SYSTEM THAT WILL MOVE INTO THE
AREA TUESDAY NIGHT AND LAST THROUGH WEDNESDAY NIGHT.
MODELS HAVE MOVED THE UPPER LEVEL TROUGH FURTHER NORTH AS IT CROSSES
THE DESERT SOUTHWEST TUESDAY NIGHT. AHEAD OF THE UPPER LEVEL TROUGH
THE LEFT EXIT REGION OF THE 500MB JET MOVES OVER WESTERN PORTIONS OF
THE AREA...BRINGING PRECIPITATION CHANCES WITH IT. GENERALLY PRECIPITATION
CHANCES IMPROVE WEDNESDAY AS THE UPPER LEVEL TROUGH MOVES
THROUGH...THEN BEGIN TO DECLINE DURING THE EVENING AS THE TROUGH MOVES
EAST OUT OF THE AREA.
THE GFS AND ECMWF CONTINUE TO DISAGREE WITH THE TIMING AND PLACEMENT
OF 700-500MB FRONTOGENESIS AND Q-VECTOR CONVERGENCE AS THE STORM
SYSTEM MOVES THROUGH. HOWEVER HIGHER CHANCES SEEMED WARRANTED FOR
MOST OF THE AREA WEDNESDAY AND WEDNESDAY NIGHT SINCE MODELS HAVE
BEEN FAIRLY CONSISTENT WITH THE PATH OF THE UPPER LEVEL TROUGH OVER
NEW MEXICO AND INTO KANSAS.
AN UPPER LEVEL TROUGH DROPS THROUGH THE AREA FROM THE NORTHWEST
BEHIND THE EXITING STORM SYSTEM THURSDAY NIGHT. WITH DRIER AIR IN
PLACE BEHIND THE STORM SYSTEM FROM WEDNESDAY...AM NOT ANTICIPATING
ANY PRECIPITATION WITH THE TROUGH PASSAGE. A SPLIT FLOW PATTERN
THEN SETS UP OVER THE AREA FRIDAY WITH AN UPPER LEVEL TROUGH OVER
THE GREAT LAKES AND A CLOSED LOW OVER NORTHERN MEXICO.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 419 AM MST SAT FEB 11 2012
MVFR TO VFR CONDITIONS WILL BE POSSIBLE FOR THE 12Z TAFS. MAIN
CONCERNS WILL BE THE DURATION OF THE MVFR VIS WITH THE LIGHT SNOW
FOR KGLD AND IF THE CEILINGS BE MVFR OR LOW VFR DURING THE DAY.
LATEST OBSERVATIONS UP STREAM OVER NORTHEAST COLORADO AND EXTREME NORTHWEST
KANSAS HAVE MVFR TO LOW VFR VIS AND VFR CEILINGS. THE SNOWFALL
WILL CONTINUE TO TAPER OFF THROUGH THE MORNING...SO THE VIS SHOULD
CONTINUE TO IMPROVE. DESPITE MODELS PLACING KGLD UNDER MVFR
CEILINGS THROUGH THE DAY AM THINKING THE CEILINGS WILL BE LOW VFR
INSTEAD...KEYING OFF OF THE OBSERVATIONS OF LOWEST CEILINGS BEING
VFR EVEN IN THE LIGHT SNOWFALL. HRRR HAS LOW MVFR CEILINGS MOVING
IN DURING THE AFTERNOON AS THE SURFACE HIGH OVER NEBRASKA MOVES
SOUTH INTO KANSAS. WITH WARMER TEMPERATURES AND THE ENVIRONMENT
DRYING OUT THROUGH THE DAY...WILL KEEP WITH THE LOW VFR CEILINGS
BUT WILL ADJUST IF NEEDED. OVERNIGHT FREEZING FOG AND LOW STRATUS
ARE POSSIBLE FOR KGLD.
KMCK WILL REMAIN IN THE DRIER AIR TODAY. AS SUCH CONDITIONS WILL
BE VFR WITH LIGHT WINDS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
KS...NONE.
NE...NONE.
&&
$$
SHORT TERM...JRM
LONG TERM....JTL
AVIATION...JTL
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
947 AM EST SAT FEB 11 2012
.SYNOPSIS...
THE ARCTIC COLD FRONT WILL HAVE EXITED EAST PAST THE MOUNTAINS BY
MIDDAY. IN ITS WAKE, EXPECT SNOW SHOWERS, GUSTY WINDS,
TEMPERATURES IN THE TEENS WITH WIND CHILL GOING SUBZERO TONIGHT.
&&
.NEAR TERM /THROUGH TONIGHT/...
PER BLEND OF RECENT SURFACE AND RADAR DATA COUPLED WITH HRRR AND
NAM MODEL OUTPUT, EXPECT THE ARCTIC COLD FRONT TO HAVE EXITED EAST
PAST THE MOUNTAINS BY NOON. IN ITS WAKE, BANDS OF LAKE-ENHANCED SNOW
SHOWERS WILL CONTINUE INTO TONIGHT. NORTHWEST WINDS CAN GUST OVER
35 MPH...UP TO 45 MPH ACROSS THE HIGHER ELEVATIONS.
TEMPERATURES WILL BE IN THE TEENS ALL LOCATIONS BY MID AFTERNOON,
IF NOT SOONER. WIND CHILLS WILL BE IN THE SINGLE DIGITS, GOING
SUBZERO TONIGHT. WIND CHILLS ACROSS THE WV-MD MOUNTAINS MAY GO TO
MINUS 10.
AT THIS JUNCTURE, HAVE MAINTAINED CURRENT FORECAST OF SNOW
AMOUNTS. THESE WILL BE QUITE VARIABLE DUE TO SNOW BANDING. IN
GENERAL, MOST LOCATIONS CAN EXPECT 1 OR 2 INCHES THIS AFTERNOON.
HIGHER ELEVATIONS AND POINTS NORTH UP TO 4 INCHES.
TONIGHT, MOST LOCATIONS WILL ADD AN INCH OF SNOW, BUT NORTH AND
MOUNTAINS, UP TO 4 INCHES.
NAM MODEL PROFILES CONTINUE TO SHOW A LOWERING SUBSIDENCE
INVERSION LATE TONIGHT, WHICH WILL CAP THE INSTABILITY, AND WEAKEN
SNOW SHOWERS WEST OF THE MOUNTAINS BY MIDNIGHT, AND OVER THE
MOUNTAINS EARLY SUNDAY MORNING.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY/...
FLOW CONTINUING OFF LAKE ERIE WILL ALLOW FOR LAKE ENHANCED SNOW
SHOWERS TO CONTINUE. LOW INVERSION LEVELS WILL CONTINUE TO KEEP
ACCUMULATIONS IN CHECK...WITH ONLY AN INCH OR SO EXPECTED. CONTINUED
STRONG WINDS WILL BRING ANOTHER DAY OF GUSTY WINDS...AND CANNOT RULE
OUT THE POSSIBILITY THAT A WIND ADVISORY MAY BE NEEDED IN THE HIGHER
ELEVATIONS ON SUNDAY. HIGH PRESSURE WILL MOVE IN FROM THE SOUTHWEST
SUNDAY NIGHT. THIS WILL SHIFT THE WIND DIRECTION OFF LAKE
ERIE...BRINGING AN END TO ALL SNOW SHOWERS.
EXPECT DRY CONDITIONS ON MONDAY WITH HIGH PRESSURE IN THE
VICINITY. CLOUDS WILL BE ON THE INCREASE MONDAY NIGHT AS AN UPPER
LEVEL TROUGH APPROACHES FROM THE WEST. BUMPED UP POPS TO HIGH
CHANCE ON TUESDAY WITH THE APPROACH OF THE TROUGH. TEMPERATURES
WILL SLOWLY MODERATE...BUT WILL REMAIN BELOW NORMAL.
&&
.LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/...
THERE IS CONSIDERABLE DISAGREEMENT IN OPERATION MODEL SOLUTIONS,
SO FORECAST SIDES CLOSEST TO THE HPC/ECMWF SOLUTION. THUS, LOW
CONFIDENCE FORECAST HAS A FAST- MOVING CLOSED LOW MOVING ACROSS
THE AREA AND BRINGING THE CHANCE OF SNOW ON THURSDAY, FOLLOWED BY
HIGH PRESSURE DRYING OUT THE FORECAST FOR THE END OF THE WEEK.
TEMPERATURES ON WEDNESDAY WILL MODERATE TO NEAR NORMAL VALUES AND
CONTINUE TO WARM TO 5 DEGREES ABOVE NORMAL FOR THURSDAY AND
FRIDAY.
&&
.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
CDFNT WL COMPLETE A SWEEP OF THE UPR OH REGION THIS MRNG WITH IFR
CONDITIONS IN -SN CONTG.
AS THE CDFNT PUSHES EWD BY THIS AFTERNOON...NW FLOW WL MAINTAIN RESTRICTIONS
IN -SHSN AND REDUCED CIGS. WIND GUSTS OF 30 TO 35KTS WL ALSO
HAMPER AVIATION. DRY ADVCTN AND GRADUALLY LOWERING INVERSION WL
IMPROVE CONDITIONS TONIGHT...BUT MVFR SC AND AT CONTG SCT -SHSN
SHOULD BE ANTICIPATED.
OUTLOOK...SUNDAY THROUGH WEDNESDAY...
COLD NWLY FLOW WL SUPPORT MVFR...TO BARELY VFR SC ON SUNDAY...BUT
BUILDING HIGH PRES SHOULD RTN PREDOMINATE VFR BY MONDAY.
SHORTWV IN ZONAL FLOW IS PROGGED TO GENERATE MORE -SN FOR MONDAY NGT
AND EARLY TUESDAY. TIMING WL HAVE TO BE MONITORED WITH THAT
PROGRESSIVE SYSTEM...BUT AT LEAST MVFR CAN BE EXPECTED WITH THAT
SYSTEM. REBUILDING HIGH PRES WOULD THEN RTN VFR BY LATE TUESDAY AND
WEDNESDAY WITH THIS SCENARIO.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER STORM WARNING UNTIL 6 AM EST SUNDAY FOR MDZ001.
OH...WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS EVENING FOR OHZ039-
048-057-058-068.
WINTER WEATHER ADVISORY UNTIL 6 AM EST SUNDAY FOR OHZ040-041-
049-050-059-069.
PA...WINTER WEATHER ADVISORY UNTIL 6 AM EST SUNDAY FOR PAZ007>009-
013>016-020>023-029-031-073-075.
WINTER STORM WARNING UNTIL 6 AM EST SUNDAY FOR PAZ074-076.
WV...WINTER WEATHER ADVISORY UNTIL 6 AM EST SUNDAY FOR WVZ001>004-
012-021-022.
WINTER STORM WARNING UNTIL 6 AM EST SUNDAY FOR WVZ023-041.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
832 AM EST SAT FEB 11 2012
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 446 AM EST SAT FEB 11 2012
LATEST WV IMAGERY AND RUC ANALYSIS REVEALS THE CENTER OF THE POLAR
VORTEX EAST OF HUDSON BAY WITH A MID/UPPER LEVEL TROUGH AXIS
EXTENDING SOUTH INTO THE CENTRAL GREAT LAKES. AT THE SFC...A 1044 MB
ARCTIC HIGH WAS CENTERED OVER THE DAKOTAS. RADAR IMAGERY AND SFC OBS
SHOW WIND PARALLEL LES BANDS FROM EAST OF MQT TO GRAND MARAIS BEING
SUPPORTED BY ENHANCED LOW-LVL CONVERGENCE FROM NW WIND FLOW ACROSS
MUCH OF LAKE SUPERIOR AND THEN LAND BREEZE CIRCULATION OFF OF
ONTARIO CAUSING A NE WIND OVER FAR ERN LAKE SUPERIOR. LES BANDS WITH
RETURNS TO 30 DBZ ARE FAIRLY WELL SPACED APART DUE TO VERY DRY
UPSTREAM AND LARGE SCALE ANTICYCLONIC FLOW ACROSS THE AREA. SURGE OF
MID TO LOW-LVL MOISTURE IN WAA PATTERN MOVING IN FROM NORTH OF LAKE
SUPERIOR IS SHOWING SIGNS OF ENHANCING LES BANDS ACROSS THE LAKE IN
THE PAST HR OR SO. THIS WILL BE SOMETHING TO MONITOR AS THE DAY
PROGRESSES TO SEE IF IT WILL BOOST LES ACCUMS DOWNWIND OF THE LAKE.
TODAY...AS 850-700 MB MOISTURE INCREASES IN A DEVELOPING WAA PATTERN
THERE COULD BE A BRIEF INCREASE IN LES INTENSITY FOR THE ERN
COUNTIES FAVORED BY A WNW/NW WIND. AS I SAID...BELIEVE ANY FLARE UP
IN LES WILL BE SHORT-LIVED SINCE WAA AND RISING 850 MB TEMPS WILL
EVENTUALLY FORCE THE DGZ ABV THE BEST OMEGA/UPWARD MOTION WITHIN THE
CONVECTIVE BOUNDARY LAYER BY THE LATE AFTERNOON/EVENING HRS. LONGER
FETCH ACROSS THE LAKE ALONG WITH MORE FAVORABLE LES PARAMETERS
SUGGEST BEST SNOW ACCUMULATIONS WILL BE OVER THE NE FCST
AREA...WHERE AMOUNTS IN THE 2 TO 4 INCH RANGE ARE POSSIBLE...JUST
BLO ADVISORY CRITERIA. ELSEWHERE...NEAR LAKE SUPERIOR EXPECT LES
AMTS GENERALLY 2 INCHES OR LESS.
TONIGHT...TROF ASSOCIATED WITH POLAR VORTEX E OF HUDSON BAY WILL
BEGIN SHIFTING E OF THE REGION...ALLOWING FOR PROMINENT RIDGING AND
WAA REGIME TO SET UP AND CONTINUE INTO SUN. LES WILL BE ONGOING SAT
EVENING OVER THE E AT LOCATIONS FAVORED BY A WNW/NW WIND OFF LAKE
SUPERIOR. HOWEVER...INVERSION QUICKLY SETTLES DOWN TO 4KFT OR LWR BY
LATE EVENING AND OVERNIGHT. ALSO...CONTINUED WAA WILL KEEP THE
DENDRITIC SNOW GROWTH TEMP ZONE (DGZ) UP ABOVE BEST UPWARD MOTION.
IN GENERAL...MIGHT SEE ANOTHER 1-2...POSSIBLY UP TO 3 INCHES OF SNOW
OVER THE NE FCST AREA SAT NIGHT. OUT W...INVERSION WILL ALREADY BE
SETTLING TO 3KFT OR LWR EARLY IN THE EVENING WITH DGZ ABOVE THE
INVERSION. GIVEN THE LOW INVERSION AND MODERATING AIRMASS...THERE
MAY NOT BE MUCH LEFT OTHER THAN FLURRIES THIS EVENING WITH GRADUAL
CLEARING THEN FOLLOWING DURING THE NIGHT FROM THE W. WITH
CLEARING...MINS COULD DROP NEAR ZERO IN THE TRADITIONAL COLD SPOTS
OVER THE INTERIOR W HALF. NEAR LAKE SUPERIOR WHERE THERE WILL BE
BETTER MIXING AND MODERATION FROM ONSHORE NW FLOW TO KEEP MIN TEMPS
IN THE TEENS.
SUNDAY...LINGERING LIGHT LES/FLURRIES OVER THE NE FCST AREA WILL END
IN THE MORNING AS THE INVERSION CONTINUES TO LWR AND MORE
IMPORTANTLY TEMPS AT INVERSION BASE RISE ABOVE -10C. AWAY FROM
DIMINISHING LIGHT LES E...IT SHOULD TURN OUT TO BE A MAINLY SUNNY
DAY UNDER A DEEP DRY AIR MASS. DRY AIR MASS AND SUNSHINE WORKING ON
THE LWR ALBEDO FORESTED LANDSCAPE OF UPPER MI WILL ASSIST THE WARM
UP...BUT STRONG INVERSION WILL HOLD BACK THE WARMING POTENTIAL OVER
WHAT IT COULD BE. FCST SOUNDINGS SUGGEST MIXING TO JUST ABV 925 MB
LOOK FOR HIGHS GENERALLY IN THE MID/UPPER 20S.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 446 AM EST SAT FEB 11 2012
UPPER TROUGH WILL BE ROTATING E OF THE AREA AT THE START OF THE LONG
TERM PERIOD...LEADING TO THE AREA BEING BETWEEN THE SPLIT FLOW OF
THE NRN STREAM RIDGE OVER THE CANADIAN PRAIRIES AND THE SRN STREAM
RUNNING ACROSS THE SRN FOURTH OF THE CONUS. THIS WILL KEEP THE AREA
UNDER QUIET WEATHER TO START THE PERIOD WITH A HIGH PRESSURE RIDGE
PUSHING OVER THE WRN CWA SUN NIGHT AND MON...WHILE BROAD H850-700
WAA INTENSIFIES OVER STATIONARY FRONT OVER SE ONTARIO.
SUN NIGHT...EXPECT A MOSTLY CLEAR NIGHT WITH THE HIGH PRESSURE RIDGE
PUSHING OVER THE AREA. LOWS WILL DEPEND ON HOW QUICKLY WINDS CAN
DECOUPLE ON MON NIGHT...AS GRADIENT BETWEEN STATIONARY FRONT AND
APPROACHING SFC RIDGE TRIES TO KEEP WINDS UP. BEST CHANCE FOR LIGHT
WINDS WILL BE CLOSER TO THE SFC RIDGE OVER THE SW HALF OF THE
CWA...WHERE PWAT VALUES FALL TO 40 PERCENT OF NORMAL. HAVE TRENDED
TOWARDS THE LOW END OF GUIDANCE...BUT NOT QUITE AS COLD AS IF THE
WAS HIGHER CONF FOR LIGHT WINDS.
MON...AREA WILL BE BETWEEN SFC TROUGH IN SE ONTARIO AND H500
SHORTWAVE AND ASSOCIATED HEIGHT FALLS MOVING THROUGH THE MID MISS
VALLEY AND APPROACHING THE LOWER GREAT LKS MON NIGHT. EXPECT A
MOSTLY SUNNY DAY FOR MUCH OF THE AREA...ALTHOUGH CLOUDS WILL ATTEMPT
TO PUSH ACROSS THE WI BORDER LATE IN THE AFTN WITH MOISTURE
INCREASING AHEAD OF THE SHORTWAVE. HIGHS WILL DEPEND ON AMNT OF
MIXING. MODELS INDICATING MIXING UP TO H900...WHICH WOULD PRODUCE
HIGHS OF 30-35. WITH ABUNDANT SUNSHINE TO START THE DAY...FELT TEMPS
WILL WARM UP QUICKLY AND ONLY MADE A DEGREE OR TWO ADJUSTMENT UP TO
GOING HIGHS.
MODELS CONSISTENT IN H850-650 MOISTURE MOVING INTO THE SRN HALF OF
THE AREA MON NIGHT AS THE SHORTWAVE MOVES SOUTH OF THE CWA. BUT WITH
LACK OF ISENTROPIC ASCENT...WAA...AND MAIN FORCING S OF THE CWA WITH
H500 HEIGHT FALLS...THINK PCPN CHANCES ARE FAIRLY LIMITED.
THEREFORE...HAVE JUST A SLIGHT CHANCE OVER THE SCNTRL CWA AND
CHANCES BRUSHING THE CITY OF MENOMINEE.
DAYS 4 THROUGH 7 /TUES THROUGH FRIDAY/...
SRN STREAM TROUGH WILL BEGIN TO DIG OVER THE SW CONUS ON
TUES...ALLOWING RIDGING TO DEVELOP OVER THE SRN/CNTRL PLAINS AND
CONTINUE INTO WED. MEANWHILE...TROUGH WILL START TO AMPLIFY OVER THE
CANADIAN ROCKIES IN THE NRN STREAM ON TUES AND ATTEMPT TO MERGE WITH
THE SRN STREAM WED NIGHT INTO THURS. THESE SITUATIONS TEND TO BE
DIFFICULT FOR MODELS...BUT 00Z GFS/ECMWF/GEM AND ASSOCIATED ENS
MEANS HANDLE THE LARGE SCALE FEATURES SIMILARLY BUT DO HAVE
DIFFICULTY WITH THE EMBEDDED SHORTWAVES. THUS...HAVE AVERAGE CONF
FOR MUCH OF THE EXTENDED PERIOD.
INITIAL SYSTEM EXITS THE AREA ON TUES...LEAVING AREA IN WSWRLY LLVL
FLOW AND H850 TEMPS AROUND -8C. THIS PROVIDES LIMITED POTENTIAL FOR
LES AND WILL LIKELY SEE MOSTLY CLOUDY SKIES LINGERING INTO WED WITH
NEXT POTENTIAL SHORTWAVE MOVING THROUGH...ALTHOUGH MODELS HAVE LARGE
DIFFERENCES IN INTENSITY.
NRN/SRN STREAMS LOOK TO PHASE ON THURS. WITH THE MORE DOMINATE SRN
STREAM...EXPECT SFC LOW DEVELOPMENT TO FOLLOW THE SRN STREAM TRACK
THAT WILL LIKELY TAKE IT THROUGH THE OHIO VALLEY OR LOWER GREAT LKS.
THIS WOULD BRUSH THE SE CWA AS BEST FORCING/MOISTURE REMAINS CLOSER
TO THE LOW. 00Z ECMWF DID TREND A LITTLE FARTHER NW WITH THE TRACK
OF THE LOW...SO WILL NEED TO WATCH ON FUTURE SHIFTS.
MODELS BEGIN TO DIVERGE HEADING INTO FRI WITH THE HANDLING OF THE
NRN STREAM FEATURES AND WHERE THE SRN STREAM UPPER TROUGH IS LOCATED
OVER THE SW CONUS. H850 TEMPS AROUND -11C WOULD LEAD TO SOME LES
POTENTIAL UNDER NW WINDS...BUT LLVL MOISTURE OVER THE W MAY BE
LIMITED. THEREFORE...ONLY MENTIONED CHANCE POPS OVER THE ERN AREAS
FAVORED BY NW WINDS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 832 AM EST SAT FEB 11 2012
LES IS EXPECTED TO REDEVELOP AT CMX AND IWD TODAY AS MOISTURE
INCREASES AGAIN WITH NW FLOW. EXPECT MVFR CONDITIONS TO GENERALLY
PREVAIL WITH ONLY BRIEF PERIODS OF IFR POSSIBLE. KCMX WILL HAVE THE
BEST CHANCE OF SEEING IFR CONDITIONS GIVEN MORE FAVORABLE WRLY FLOW
FOR LES AND POSSIBLE BLOWING SNOW AS WIND GUSTS EXCEED 25 KTS.
CONDITIONS WILL IMPROVE AT BOTH KIWD AND KCMX THIS EVENING AS WAA
WILL HELP SHUT OFF LES CHCS. AT SAW...NW FLOW WILL NOT BE FAVORABLE
FOR LES. MVFR CIGS SHOULD GIVE WAY TO VFR CONDITIONS THIS EVENING AS
WINDS BACK TO THE WNW.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 446 AM EST SAT FEB 11 2012
NNW WINDS TO 30KT WILL PERSIST WITH AMPLE INSTABILITY IN THE ARCTIC
AIRMASS MOVING OVER THE REGION. NW WINDS APPROACHING GALES TO 35 KT
ARE ALSO POSSIBLE THIS AFTERNOON INTO THIS EVENING OVER ERN LAKE
SUPERIOR. EXPECT HEAVY FREEZING SPRAY ACROSS THE ENTIRE LAKE THROUGH
TONIGHT WITH THE STRONG WINDS AND WAVE ACTION. LOOK FOR HEAVY
FREEZING SPRAY TO END ON SUNDAY AS THE AIRMASS WARMS AND WINDS
GRADUALLY DIMINISH. CONDITIONS WILL QUIET DOWN FOR THE EARLY PART OF
THE WORK WEEK AS A HIGH PRES RIDGE MOVES OVER THE UPPER GREAT LAKES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST /6 AM CST/ SUNDAY
FOR LSZ162-240>251-263>267.
GALE WARNING FROM 5 PM THIS AFTERNOON TO 3 AM EST SUNDAY FOR
LSZ248>250-265-266.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...SRF
AVIATION...VOSS
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
532 AM CST SAT FEB 11 2012
.SHORT TERM...TONIGHT THROUGH MONDAY NIGHT
249 AM CST SAT FEB 11 2012
MAIN FORECAST CONCERN IS ON PRECIPITATION FOR MONDAY
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS
SHOWED TROUGHING COMING INTO CALIFORNIA...RIDGING FROM ARIZONA INTO
SASKATCHEWAN...AND TROUGHING FROM QUEBEC INTO ILLINOIS. THE FORECAST
AREA LIES IN SUBSIDENCE IN THE WAKE OF THE TROUGHING...PROMOTING A
FEED OF DRIER AIR INTO THE FORECAST AREA. 00Z MPX SOUNDING AS WELL
AS A PRECIPITABLE WATER PLOT OF 00Z RAOB DATA ACROSS THE UPPER
MIDWEST REFLECTIVE OF THE DRY AIR...WITH VALUES AROUND 0.05 OF AN
INCH OR 25 PERCENT OF NORMAL. WITH ALL THE DRY AIR...SKIES ARE
CLEAR. ARCTIC AIR SLOWLY FLOWING IN TOO WITH THE DRY AIR ON A
SUSTAINED 10 TO 15 MPH NORTHWEST WIND. TEMPERATURES HAVE FALLEN INTO
THE SINGLE DIGITS ABOVE ZERO. THE LACK OF SNOW COVER AND PERSISTENT
WIND KEEPING TEMPERATURES FROM FALLING MUCH LOWER. COMBINATION OF
THE WIND AND TEMPERATURES RESULTING IN WIND CHILLS MOSTLY IN THE
SINGLE DIGITS OR TEENS BELOW ZERO. AREA OF HIGH PRESSURE ASSOCIATED
WITH THE SUBSIDENCE FAR OFF TO THE WEST...OVER THE DAKOTAS. NO BIG
CHANGE IN 850MB TEMPS FROM 12Z FRI TO 00Z SATURDAY AT BIS...ABR AND
MPX...ALL SITTING BETWEEN -17 AND -20C. HOWEVER...DVN AND GRB WHICH
WERE ALONG THE ARCTIC FRONT AT 12Z DROPPED 9 TO 11C BY 00Z.
TODAY THROUGH SUNDAY...UPPER RIDGING SEEN OVER ARIZONA AND UTAH IS
FORECAST TO BUILD EAST INTO THE PLAINS AND EVENTUALLY THE UPPER
MISSISSIPPI RIVER VALLEY BY LATE SUNDAY...DUE TO TROUGHING MOVING
INTO THE ROCKIES AND FOUR CORNERS REGION. THE FORECAST AREA WILL
REMAIN ON THE EAST SIDE OF THE UPPER RIDGING...PROMOTING SUBSIDENCE
AND CONTINUED DRY AIR ADVECTION. HOWEVER...THE BUILDING HEIGHTS IN
CONJUNCTION WITH THE LACK OF SNOW COVER AND PLENTY OF SUN SHOULD
HELP THE ARCTIC AIRMASS MODERATE THIS WEEKEND. 850MB TEMPS REFLECT
THE MODERATING...CLIMBING TO AROUND -12C AT 00Z SUNDAY AND -6C AT
00Z MONDAY. THE DRY AIRMASS IN PLACE SHOULD ALSO PROMOTE GOOD
MIXING. GIVEN 850MB TEMPS TODAY...HIGHS ARE ONLY EXPECTED IN THE MID
TEENS TO AROUND 20. THE BLUSTERY NORTHWEST WIND WILL MAKE IT FEEL
COOLER...THOUGH...WITH WIND CHILLS ONLY CLIMBING TO AROUND ZERO.
PLENTY OF WIND ANTICIPATED TONIGHT GIVEN THE SURFACE RIDGE TAKING A
TRACK TO OUR SOUTHWEST. THIS WIND SHOULD KEEP LOWS MOSTLY IN THE
SINGLE DIGITS ABOVE ZERO. ANTICIPATING WE CAN TACK ON ANOTHER 10
DEGREES OF WARMING FOR SUNDAY GIVEN THE 6C JUMP IN 850MB TEMPS.
REGARDING THE WIND CHILL ADVISORY...VERY MARGINAL CONDITIONS AT
BEST. SINCE IT IS ALREADY UP AND WIND CHILLS ARE AT LEAST IN THE
TEENS BELOW ZERO...FIGURE IT IS NOT WORTH CANCELING.
SUNDAY NIGHT THROUGH MONDAY NIGHT...FOCUS TURNS TO THE TROUGHING
OVER THE WESTERN U.S AT 00Z MONDAY. GOOD MODEL AGREEMENT EXISTS FOR
THIS TROUGHING TO CROSS THE PLAINS ON MONDAY...THEN SHEAR APART
MONDAY NIGHT AS IT CROSSES THE FORECAST AREA AND THROUGH THE OHIO
VALLEY. BEST 500MB HEIGHT FALLS FOR THE FORECAST AREA OCCUR MONDAY
AFTERNOON AND EVENING...RANGING FROM 40 TO 70 METERS PER 12 HOURS...
HIGHEST IN THE FAR SOUTHERN SECTIONS OF THE AREA. SO THE DPVA
FORCING IS FAIRLY DECENT. ISENTROPIC LIFT FIELDS...ON THE OTHER
HAND...ARE TERRIBLE WITH BASICALLY VERY LITTLE IF ANY NET ADIABATIC
OMEGA FROM EITHER THE 11.00Z NAM OR GFS. BEST 850 TO 700MB MOISTURE
TRANSPORT ALSO NOT THAT IMPRESSIVE...MOSTLY FOCUSED IN MISSOURI...
ILLINOIS AND ARKANSAS. SO BASICALLY ALL PRECIPITATION PRODUCTION
WILL COME FROM THE 500MB HEIGHT FALLS ACTING ON THE WEAKER MOISTURE
BEING TRANSPORTED UP INTO THE AREA. CERTAINLY GOOD MODEL AGREEMENT
EXISTS OF PRECIPITATION SPREADING SOUTHWEST TO NORTHEAST ACROSS MUCH
OF THE FORECAST AREA ON MONDAY...ESPECIALLY DURING THE AFTERNOON...
WHICH SEEMS REASONABLE. RAISED PRECIPITATION CHANCES UP A LITTLE
MORE FOR THE AFTERNOON...MAINLY ALONG AND SOUTH OF I-90. THINK THE
11.00Z NAM QPF IS A LITTLE TOO HIGH GIVEN LACK OF ISENTROPIC LIFT
AND STRONGER MOISTURE TRANSPORT. STILL...COULD PICK UP ANYWHERE FROM
A HALF INCH TO TWO INCHES OF SNOW OUT OF THE EVENT...HIGHEST ACROSS
THE SOUTH WHERE THE BETTER FORCING IS. PRECIPITATION SHOULD SLOWLY
DIMINISH MONDAY NIGHT AS THE UPPER TROUGHING SHEARS APART...REDUCING
THE DPVA LIFT. REGARDING TEMPERATURES...WITH THE PRECIPITATION AND
CLOUDS TRENDING SLOWER TO MOVE IN FOR SUNDAY NIGHT INTO MONDAY
MORNING...LOWERED TEMPERATURES A FEW DEGREES SUNDAY NIGHT AND STAYED
WITH A NORMAL DIURNAL TREND. POTENTIAL DOES EXIST MONDAY MORNING FOR
A LITTLE SUN NORTH OF I-94...THUS HIGHS ON MONDAY END UP WARMEST
NORTH OF I-94. SOUTHERLY ADVECTION OF WARM AIR AHEAD OF THE TROUGH
SHOULD RESULT IN HIGHS AGAIN IN THE UPPER 20S TO AROUND 30. WITH
PLENTY OF CLOUDS LINGERING MONDAY NIGHT AND LITTLE IN THE WAY OF
COLD ADVECTION...ANTICIPATING TEMPERATURES TO ONLY DROP AROUND 5
DEGREES.
.LONG TERM...TUESDAY THROUGH FRIDAY NIGHT
249 AM CST SAT FEB 11 2012
LONG TERM FORECAST LOOKS A LITTLE MORE UNCERTAIN TODAY...THOUGH THE
FEATURES SEEN YESTERDAY OF A SPLIT FLOW PATTERN REMAIN. THE BIGGEST
UNCERTAINTY IS WEDNESDAY NIGHT AND THURSDAY. DURING THIS PERIOD...
THE NEW 11.00Z ECMWF SUGGESTS TROUGHING COMING OUT OF THE SOUTHWEST
U.S. AND EVENTUALLY PHASING WITH A NORTHERN STREAM SHORTWAVE TROUGH
NEAR THE FORECAST AREA. THE RESULT WOULD PROBABLY BE AN
ADVISORY-TYPE WET SNOW EVENT FOR THE SOUTHEASTERN HALF OF THE
FORECAST AREA. PROBLEM IS...THE ECMWF IS THE ONLY MODEL SHOWING THIS
PHASING POTENTIAL. THE 11.00Z GFS/UKMET KEEP THE TWO SEPARATED WITH
THE SOUTHWESTERN TROUGH EJECTING FARTHER SOUTH. MEANWHILE...THE
11.00Z CANADIAN HAS MORE FOCUS ON THE NORTHERN STREAM FEATURE AND
PRODUCES A FAIRLY AMPLIFIED TROUGH OVER MINNESOTA ON THURSDAY. THE
11.00Z GFS ENSEMBLES DEPICT A SIMILAR AMOUNT OF UNCERTAINTY.
THEREFORE...FOR NOW FOLLOWED A CONSENSUS BLEND FOR PRECIPITATION
CHANCES WHICH END UP 20-40. PLUS...IT IS HARD TO TRUST PHASING THIS
FAR OUT.
OTHERWISE...PRECIPITATION FROM MONDAY NIGHT SHOULD FOR THE MOST PART
END TUESDAY AS THE LINGERING SHORTWAVE TROUGH FALLS APART. THIS
LEAVES DRY CONDITIONS FOR TUESDAY NIGHT AND WEDNESDAY...WHICH SHOULD
ALSO BE ASSOCIATED WITH SOME SMALL 500MB HEIGHT RISES AND A SURFACE
RIDGE OF HIGH PRESSURE. AFTER WHATEVER HAPPENS WITH THE WEDNESDAY
NIGHT THROUGH THURSDAY TIME PERIOD...GOOD AGREEMENT EXISTS OF A
WEST-NORTHWEST FLOW PATTERN HEADING INTO NEXT WEEKEND WITH HARD TO
TIME SHORTWAVES MOVING THROUGH THE FLOW. GIVEN THAT HIGH PRESSURE
SHOULD DOMINATE ACROSS THE SOUTHERN U.S. IN THE WAKE OF THE THURSDAY
SYSTEM...PREVENTING MOISTURE RETURN FROM THE GULF OF MEXICO FOR A
LITTLE WHILE...KEPT CONDITIONS DRY FOR FRIDAY.
ONE THING THAT DOES LOOK CERTAIN FOR THE LONG TERM PERIOD IS
TEMPERATURES TO REMAIN AT OR ABOVE NORMAL. A BRIEF SHOT OF COOL AIR
MAY COME THROUGH ON THURSDAY WITH 850MB TEMPS FALLING TO -6 TO -8C.
STILL...THIS WOULD BE ABOVE NORMAL. STAYED PRETTY MUCH WITH A BLEND
OF ALL GUIDANCE FOR TEMPERATURES AS IT SEEMS REASONABLE AT THIS
POINT.
&&
.AVIATION...TODAY AND TONIGHT
526 AM CST SAT FEB 11 2012
A TIGHT PRESSURE GRADIENT WILL REMAIN ACROSS THE AREA TODAY.
SUSTAINED NORTHWEST WINDS WILL REMAIN IN THE 15 TO 20 KNOT RANGE
TODAY...AND 10 TO 15 KNOTS TONIGHT. IN ADDITION TO THESE WINDS
WILL GUST TO AROUND 25 KNOTS BETWEEN 11.16Z AND 12.02Z. BOTH
CEILINGS AND VISIBILITIES WILL REMAIN VFR THROUGH THIS TIME PERIOD.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
249 AM CST SAT FEB 11 2012
WI...WIND CHILL ADVISORY UNTIL 9 AM CST THIS MORNING FOR WIZ017-029-
034.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...BOYNE
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
346 PM EST SAT FEB 11 2012
.SYNOPSIS...
LOW PRESSURE EXITING TO THE CANADIAN MARITIMES AND HIGH PRESSURE TO
OUR WEST OVER THE PLAINS STATES WILL PRODUCE A STRONG NORTHWESTERLY
FLOW WITH COLDER AIR MOVING INTO OUR REGION. LATE SUNDAY, A FRONTAL
BOUNDARY WILL PASS THROUGH THE AREA. HIGH PRESSURE BUILDS INTO THE
MID ATLANTIC ON MONDAY, FOLLOWED BY A COUPLE OF WEAK SYSTEMS
AFFECTING THE REGION DURING THE MIDDLE TO END OF THE UPCOMING WEEK.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
TWO FORECAST ISSUES FOR TONIGHT INCLUDE SNOW SHOWERS/SQUALLS WITH
THE ARCTIC FRONT...AND WIND GUSTS IN THE COLD AIR ADVECTION BEHIND
THE FRONT. A WIND ADVISORY WILL BE ISSUED FOR SOUTHERN PORTIONS OF
THE AREA WITH THE NEW FORECAST.
CURRENTLY...THE ARCTIC FRONT STRETCHES ACROSS CENTRAL PENNSYLVANIA
AND CENTRAL MARYLAND. SNOW SHOWERS WITH THE FRONT ARE FAIRLY
IMPRESSIVE (AND ALMOST LOOKS LIKE A SUMMER LIKE SQUALL LINE). THE
SNOW SHOWERS ARE BEING SUPPORTED BY A FAIRLY POTENT MID LEVEL SHORT
WAVE LOCATED ACROSS WESTERN PENNSYLVANIA...WHERE MID LEVEL LAPSE
RATES ARE STEEPENING QUICKLY. AHEAD OF THE FRONT...SCATTERED SNOW
SHOWERS NORTH AND RAIN SHOWERS SOUTH HAVE DEVELOPED IN THE BROAD ARE
OF LIFT AHEAD OF THE SHORT WAVE.
EXTRAPOLATION AND THE LATEST HRRR MODEL RUN (WHICH HAS HAD A GOOD
HANDLE ON THE FRONTAL POSITION AND STRENGTH ALL DAY) PLACES THE
FRONT IN THE DELAWARE VALLEY CLOSE TO 2300 UTC. SINCE THERE IS SNOW
SHOWER COVERAGE SHOULD MORE OR LESS MAINTAIN ITSELF...THE BEST
CHANCE OF SNOW SHOWERS SHOULD OCCUR ACROSS THE SOUTHERN HALF OF THE
AREA...WHERE THE MOISTURE WITH THE FRONT IS DEEPEST.
SOME LOCATIONS COULD SEE AN INCH OF SNOW WITH THIS FEATURE. SINCE
SURFACE TEMPERATURES ARE ABOVE FREEZING IN MOST PLACES (AND SHOULD
REMAIN THERE THROUGH THE FRONTAL PASSAGE)...WE HAVE DECIDED NOT TO
GO WITH AN WINTER WEATHER ADVISORY FOR THE SNOW SHOWERS. HOWEVER...
THE SNOW SHOWERS COULD HAVE GUSTY WINDS AS WELL...AND THREAT SHOULD
BEST BE HANDLED BY A SPECIAL WEATHER STATEMENT.
THE ARCTIC FRONT WILL CLEAR THE COAST AFTER ABOUT 1000 PM...WITH THE
BEST CHANCE OF SNOW SHOWERS FOLLOWING CLOSELY BEHIND. AFTER
THIS...IMPRESSIVE COLD AIR ADVECTION AND A TIGHTENING GRADIENT RAISE
THE SPECTER FOR STRONG WINDS OVERNIGHT...MAINLY ACROSS SOUTHERN
AREAS.
THE PRESSURE GRADIENT LOOKS TO FALL OUT ACROSS THE SOUTHERN HALF OF
THE FORECAST AREA...WITH THE TIGHTEST GRADIENT BETWEEN 0600 AND 1200
UTC SUNDAY. DURING THE BEST COLD AIR ADVECTION...MODEL SOUNDINGS
FROM BOTH THE 1200 UTC NAM AND GFS SHOW 45 KNOT WINDS AT THE TOP OF
THE INVERSION NEAR 2100 FEET...PEAKING BETWEEN 0600 UTC AND 0900
UTC. THIS IS PROBABLY BORDERLINE FOR WIND ADVISORY CRITERIA...BUT 3
HOUR PRESSURE RISES NEAR 5 MB MAY BE ENOUGH TO ALLOW SOME OF THAT
MOMENTUM TO REACH THE SURFACE.
THE WIND ADVISORY COVERS NORTHEAST MARYLAND...DELAWARE...A PART OF
SOUTHEAST PENNSYLVANIA (INCLUDING PHILADELPHIA)...AND THE SOUTHERN
HALF OF NEW JERSEY. WHILE THE STRONGEST WINDS MAY BE JUST SOUTH OF
AN KMQS-KPHL-KMJX...THE NORTHERN EDGE OF THE WIND ADVISORY WILL
INCLUDE THE METRO AREA.
LOWS TONIGHT SHOULD OCCUR TOWARD DAYBREAK IN THE BEST COLD AIR
ADVECTION. GIVEN WHAT IS OCCURRING TO THE WEST NOW...LOWS WERE BASED
ON THE COLDER GFS MOS NUMBERS.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH 6 PM SUNDAY/...
COLD AIR ADVECTION WILL BE IN PROGRESS SUNDAY MORNING...AS THE
STRONGEST LOW TO MID LEVEL WINDS MOVE JUST OFFSHORE. THE PRESSURE
GRADIENT IS AT ITS TIGHTEST IN THE MORNING...AND AT THIS POINT DOES
NOT APPEAR TO SUPPORT WIND ADVISORY LEVELS GUSTS. MODEL SOUNDINGS
ALSO SUGGEST THAT THE GUST POTENTIAL REMAINS BELOW WIND ADVISORY
LEVELS AS WELL.
A SECONDARY COLD FRONT WILL CROSS THE REGION IN THE AFTERNOON...
SUPPORTED BY A FAIRLY VIGOROUS MID LEVEL SHORT WAVE. THE COLD AIR
ADVECTION BEHIND THESE FEATURES COULD RESULT IN WIND GUSTS GETTING
CLOSE TO WIND ADVISORY LEVELS DURING THE MID TO LATE AFTERNOON
(WHICH IS SUPPORTED BY MODEL SOUNDINGS AROUND 2100 UTC). WHILE THERE
IS SOME POTENTIAL FOR GUSTS TO REACH 45 MPH SUNDAY AFTERNOON...WILL
HOLD OFF ON DOING THAT JUST YET.
SOME CLEARING IS POSSIBLE IN THE MORNING AS THE COLD AIR ADVECTION
MAXIMIZES AND DRY AIR SETTLES IN BEHIND THE ARCTIC FRONT. THIS MAY
END UP BEING SHORT LIVED HOWEVER...AS THE CONVECTIVE TEMPERATURES
PLUMMET IN THE NEW AIRMASS. MODEL SOUNDINGS SUGGEST THAT CUMULUS
WILL DEVELOP DURING THE MID MORNING HOURS...AND WILL SPREAD OUT
UNDER THE INVERSION DURING THE AFTERNOON. IN ADDITION...MID LEVEL
CLOUDINESS WITH THE ABOVEMENTIONED SHORT WAVE PROBABLY COVERS MOST
OF THE NORTHERN TWO THIRDS OF THE AREA IN THE AFTERNOON. SO...MOST
PLACES SHOULD SEE SOME SUNSHINE FADE BEHIND CLOUDINESS (WHILE THE
TERRAIN MAY SEE LITTLE IF ANY SUN DURING THE DAY SUNDAY.
THE SHORT WAVE WILL ALSO INCREASE THE UPSLOPE FLOW ACROSS THE HIGHER
TERRAIN...AND THIS COULD RESULT IN SCATTERED SNOW SHOWERS IN THE
MOUNTAINS DURING THE MORNING. THE REINFORCING COLD FRONT IN THE
AFTERNOON MAY ENHANCE THIS...BUT FOR NOW THE SNOW SHOWER CHANCES
WERE CAPPED. IN ADDITION...FLURRIES WITH THE SHORT WAVE WERE CARRIED
ACROSS THE UPPER DELAWARE VALLEY...AS WELL AS MUCH OF NORTHERN NEW
JERSEY.
850 MB TEMPERATURES STABILIZING NEAR MINUS 14 CELSIUS SUGGEST THAT
HIGHS IN MOST PLACES OUTSIDE THE TERRAIN SHOULD TOP OUT NEAR THE
FREEZING MARK. THIS IS CLOSER TO THE COLDER NAM MOS NUMBERS...WHICH
WERE USED FOR HIGHS.
&&
.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
TO BEGIN THE LONG TERM, A STRONG MID LEVEL TROUGH AND A WEAK FRONT
WILL BE EXITING OFF TO OUR EAST. OTHER THAN SOME LEFTOVER FLURRIES
IN THE NORTHWEST FLOW OVER THE HIGHER TERRAIN OF THE POCONOS, A DRY
FORECAST HAS BEEN MAINTAINED FOR SUNDAY NIGHT AS THE ABOVE FEATURES
MOVE EAST AND HIGH PRESSURE TO OUR SOUTHWEST GRADUALLY BEGINS TO
BUILD INTO THE REGION. HIGH PRESSURE NEARBY WILL YIELD FAIR WEATHER
ACROSS THE REGION ON MONDAY WITH AMPLE SUN AND TEMPERATURES A FEW
DEGREES MILDER THAN OVER THE WEEKEND. FOR THE TUESDAY TO WEDNESDAY
TIMEFRAME, THE ECMWF AND GFS CONTINUE TO SHOW A FAIRLY DISORGANIZED
MID LEVEL DISTURBANCE PASSING THROUGH THE MID ATLANTIC REGION. WITH
DIFFERENCES BETWEEN THE MODELS ON THE HANDLING OF THIS SYSTEM, FEW
CHANGES WERE MADE IN THIS TIMEFRAME WITH SLIGHT CHANCE POPS FOR
RAIN/SNOW SHOWERS MAINTAINED. OF NOTE WILL BE THE MODERATING TREND
IN TEMPERATURES AS MORE OF A SOUTHWESTERLY FLOW WILL BE IN PLACE
DURING THIS TIMEFRAME. FOR THE END OF THE WEEK, A STRONGER SYSTEM
MAY POTENTIALLY AFFECT THE REGION. FOR NOW, THE MODELS HAVE LOW
PRESSURE APPROACHING FROM THE OHIO VALLEY REGION ON THURSDAY, WITH
THIS SYSTEM REACHING OUR AREA THURSDAY NIGHT INTO FRIDAY. HOWEVER,
THERE IS QUITE A BIT OF DIFFERENCE BETWEEN THE MODELS WITH THE TRACK
AND STRENGTH OF LOW PRESSURE. FOR NOW, CHANCE AND SLIGHT CHANCE POPS
WERE KEPT FROM THURSDAY NIGHT INTO FRIDAY WITH THE PASSAGE OF THIS
SYSTEM. WHAT DOES LOOK TO CONTINUE THROUGH THE END OF THE WEEK ARE
THE MODERATING TEMPERATURES, WITH HIGH TEMPERATURES RANGING FROM THE
MID 40S NORTH TO THE LOW 50S SOUTH ON FRIDAY. FOR THE MOST PART, A
BLEND OF MOS AND HPC GUIDANCE ALONG WITH CONTINUITY WAS USED FOR
TEMPERATURES THROUGH THE LONG TERM PERIOD.
&&
.AVIATION /21Z SATURDAY THROUGH THURSDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
VARYING CONDITIONS EARLY THIS AFTERNOON WERE SLOWING IMPROVING AS
THE PRECIPITATION ENDS FROM WEST TO EAST. HOWEVER...MOISTURE REMAINS
TRAPPED UNDER THE INVERSION. A RECENT AMDAR SOUNDING FROM KPHL
SUGGESTS THAT THE INVERSION MAY BE READY TO BREAK...AND MVFR
CONDITIONS SHOULD BE THE RULE THROUGH 2200 UTC.
AN ARCTIC FRONT WILL CROSS THE REGION THIS EVENING...CENTERED AROUND
0000 UTC. FOR THE MOST PART...MVFR CONDITIONS HAVE BEEN ACCOMPANYING
THE FRONTAL PASSAGE ACROSS WESTERN AND CENTRAL PENNSYLVANIA.
THUS...MVFR CONDITIONS ARE FORECAST BETWEEN 0000 UTC AND 0400
UTC...WITH THE LOWEST CONDITIONS FROM KPHL SOUTH.
AFTER THE FRONT PASSES AND THE INVERSION ASSOCIATED WITH THE FRONT
INCREASES...VFR CONDITIONS SHOULD RETURN AFTER 0600 UTC SUNDAY.
HOWEVER...THE GRADIENT BEHIND THE ARCTIC FRONT TIGHTENS FAIRLY
QUICKLY...AND SHOULD EASILY SUPPORT SUSTAINED WINDS BETWEEN 17 AND
22 KNOTS ACROSS THE BOARD. MODEL SOUNDINGS SUGGEST THAT WINDS WILL
RANGE BETWEEN 35 AND 41 KNOTS AT THE TOP OF THE INVERSION DURING THE
BEST OF THE COLD AIR ADVECTION...SO GUSTS TO 35 KNOTS ARE EXPECTED
DURING THE OVERNIGHT HOURS...WITH THE STRONGEST GUSTS FROM KPHL
SOUTH.
VFR CEILINGS COULD BREAK FOR A TIME LATER TONIGHT AND SUNDAY
MORNING. THE NEW AIRMASS HAS FAIRLY LOW CONVECTIVE TEMPERATURES
ASSOCIATED WITH IT...SO SUNSHINE WILL BE SELF DESTRUCTIVE...ALLOWING
CUMULUS/STRATOCUMULUS TO DEVELOP. THE GRADIENT CONTINUES TO SUPPORT
SUSTAINED WINDS BETWEEN 18 AND 25 KNOTS FOR THE REMAINDER OF THE
DAY...AFTER A BRIEF LULL NEAR SUNRISE. MODEL SOUNDINGS SUGGEST THAT
THE GUST POTENTIAL IS NOT QUITE AS HIGH AS TONIGHT...AS THE MOMENTUM
TRANSFER IS NOT AS EFFICIENT AS TONIGHT.
OUTLOOK...
WITH HIGH PRESSURE GRADUALLY BUILDING INTO THE REGION FROM SUNDAY
NIGHT THROUGH MONDAY, VFR CONDITIONS ARE EXPECTED. IN THE LATE
TUESDAY TO WEDNESDAY TIMEFRAME, A WEAK SYSTEM MAY BRING
PRECIPITATION AND SOME LOWERING IN CEILINGS OR VISIBILITIES TO THE
AREA.
&&
.MARINE...
THE GRADIENT IS STARTING TO INCREASE AS THE SURFACE LOW DEEPENS WELL
TO THE EAST OF THE NORTH CAROLINA COAST. WINDS AND SEAS ARE ON THE
THRESHOLD OF SMALL CRAFT LIMITS...ESPECIALLY ACROSS THE SOUTHERN
WATERS.
AN ARCTIC COLD FRONT WILL CROSS THE WATERS THIS EVENING...REACHING
THE DELAWARE BAY BEFORE 0100 UTC...AND REACHING THE COASTAL WATERS
AFTER 0400 UTC SUNDAY. THE GRADIENT BEHIND THE FRONT IN THE COLD AIR
ADVECTION IS IMPRESSIVE OVER LAND TO THE WEST...WHERE GUSTS TO 35
KNOTS HAVE BEEN COMMON. THE GALE FORCE GUSTS ARE EXPECTED TO
COMMENCE SHORTLY AFTER THE PASSAGE OF THE ARCTIC FRONT. THE PRESSURE
GRADIENT REACHES IT MAXIMUM BETWEEN 0600 UTC AND 1200 UTC SUNDAY.
DURING THIS TIME...THE GRADIENT LOOKS TO SUPPORT GALE FORCE WINDS
ACROSS ALL WATERS...WITH THE HIGHEST GUST POTENTIAL ACROSS THE
SOUTHERN OCEAN WATERS AND LOWER DELAWARE BAY.
THE GRADIENT MAINTAINS AN INTENSITY SLIGHTLY LOWER THAN LATE TONIGHT
FOR MOST OF SUNDAY. THE HIGHEST WINDS GUSTS PROBABLY OCCUR IN THE
MORNING ACROSS THE SOUTHERN WATERS. IN FACT...WINDS COULD DROP BELOW
GALE FORCE FOR A TIME LATE IN THE MORNING AND EARLY AFTERNOON.
ANOTHER COLD FRONT DROPPING ACROSS THE WATERS IN THE AFTERNOON COULD
BRING WINDS BACK TO GALE FORCE...AS ANOTHER SHORT OF COLD AIR
CROSSES THE WATERS. MODEL SOUNDINGS SUGGEST THAT GUSTS BETWEEN 35
AND 40 KNOTS ARE POSSIBLE ACROSS THE NORTHERN OCEAN WATERS...WITH
SLIGHTLY LESS POTENTIAL ACROSS THE SOUTHERN WATERS.
GALE CONDITIONS ARE ANTICIPATED TO LINGER INTO SUNDAY NIGHT, WITH
DECREASING WINDS AND DIMINISHING SEAS GOING INTO EARLY MONDAY. IN
FACT, FROM MONDAY THROUGH MID-WEEK, WINDS AND SEAS ARE EXPECTED TO
BE BELOW ADVISORY CRITERIA, WITH HIGH PRESSURE OVER THE REGION ON
MONDAY AND A WEAK SYSTEM MOVING THROUGH THE AREA FOR MID-WEEK.
&&
.TIDES/COASTAL FLOODING...
AS THE STRONG NORTHWEST FLOW DEVELOPS...ANY POSITIVE TIDE DEPARTURES
ON THE OCEAN AND ACROSS THE BAYS SHOULD DISAPPEAR. NONE OF THE TIDAL
GUIDANCE SUGGESTS THAT BLOWOUT TIDES WILL BE AN ISSUE TONIGHT AND
SUNDAY.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...WIND ADVISORY FROM 7 PM THIS EVENING TO 5 AM EST SUNDAY FOR
PAZ067-070-071.
NJ...WIND ADVISORY FROM 7 PM THIS EVENING TO 5 AM EST SUNDAY FOR
NJZ016>024-026-027.
DE...WIND ADVISORY FROM 7 PM THIS EVENING TO 5 AM EST SUNDAY FOR
DEZ001>004.
MD...WIND ADVISORY FROM 7 PM THIS EVENING TO 5 AM EST SUNDAY FOR
MDZ008-012-015-019-020.
MARINE...GALE WARNING UNTIL 1 AM EST MONDAY FOR ANZ430-431-450>455.
&&
$$
SYNOPSIS...KLINE
NEAR TERM...HAYES
SHORT TERM...HAYES
LONG TERM...KLINE
AVIATION...HAYES/KLINE
MARINE...HAYES/KLINE
TIDES/COASTAL FLOODING...HAYES
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
1239 PM EST SAT FEB 11 2012
.SYNOPSIS...
LOW PRESSURE SOUTHEAST OF THE AREA WILL DEEPEN AS IT MOVE
NORTHEAST THIS AFTERNOON. A COLD FRONT WILL CROSS OUR AREA THIS
LATE AFTERNOON AND THIS EVENING. THERE WILL BE A STRONG NORTHWEST FLOW
AND SOME COLDER AIR IN THE WAKE OF THE FRONT. A SECONDARY COLD
FRONT WILL CROSS THE AREA LATE SUNDAY. HIGH PRESSURE WILL BUILD IN
ON MONDAY, THEN TWO WEAK SYSTEMS COULD AFFECT THE REGION DURING
THE MIDDLE TO LATTER PART OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE BANDED FEATURES HAVE MOVED OFFSHORE WITH THE LAST OF THE MID
LEVEL FRONTOGENETIC FORCING. PATCHES OF LIGHT SNOW CONTINUE TO
FORM IN THE MOIST COLUMN LEFT IN PLACE ACROSS EASTERN PENNSYLVANIA
AND MARYLAND EARLY THIS AFTERNOON.
ANOTHER BATCH OF SNOW SHOWERS IS MOVING STEADILY ACROSS EAST
CENTRAL MARYLAND...AND SHOULD IMPACT THE NORTHEAST MARYLAND ZONES
LATER THIS AFTERNOON. THE LATEST HRRR SHOWS AN ALMOST SQUALL- LIKE
STRUCTURE MOVING THROUGH THE PENNSYLVANIA AND EASTERN MARYLAND BY
ABOUT 2200 UTC. GIVEN THE LAPSE RATES IN THE LOW AND MID
LEVELS...THIS TYPE OF STRUCTURE LOOKS POSSIBLE. A BURST OF SNOW IS
POSSIBLE WITH THE FRONT ITSELF.
FOR NOW...THE POTENTIAL FOR SNOW SHOWERS WAS INCREASED ACROSS
SOUTHERN AREAS. IF THE CONVECTIVE ELEMENTS PERSIST...A SPECIAL
WEATHER STATEMENT WILL BE ISSUED TO HIGHLIGHT THE POTENTIAL FOR A
BRIEF PERIOD OF MODERATE SNOW THERE. ELSEWHERE...NOT MUCH CHANGE
TO THE ONGOING FORECAST...AS TEMPERATURES PROBABLY DO NOT MOVE
MUCH FROM WHERE THEY ARE NOW.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SUNDAY/...
THE UPPER TROUGH WILL CROSS THE REGION TONIGHT. A SHARP SFC COLD
FRONT WILL CROSS THE AREA THIS EVENING. IT WILL BE ACCOMPANIED BY
GUSTY WINDS...FALLING TEMPERATURES AND SCATTERED SNOW SHOWERS. A
BETTER CHC FOR THE SNOW SHOWERS WILL BE ACROSS THE DELMARVA CLOSER
TO THE VORT MAX ALONG THE H5 TROUGH. HIGH CHC OR LOW LIKELY POPS
WILL BE OVER THE DELMARVA (AND CHESTER CTY PA) WHILE LOWER CHC POPS
WILL BE OVER THE REST OF PA AND NJ. TEMPERATURES WILL PLUNGE INTO
THE TEENS OVER THE POCONOS...LEHIGH VALLEY AND NRN NJ AND INTO THE
20S ELSEWHERE. WIND CHILL VALUES WILL BE IN THE SINGLE DIGITS WITH
SOME SUB-ZERO READINGS OVER THE SRN POCONOS. WINDS WILL GUST IN THE
25 TO 35 KT RANGE TONIGHT...ESPECIALLY OVER THE SRN COUNTIES.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
THE FAIRLY SHARP MID LEVEL TROUGH AXIS WILL DEVELOP A NEGATIVE
TILT AS IT LIFTS AWAY FROM OUR AREA ON SUNDAY, AND A SECONDARY
IMPULSE WILL DROP DOWN THE BACK SIDE OF IT AROUND SUNDAY EVENING.
SURFACE PRESSURE RISES IN THE WAKE OF THE TROUGH ARE ROBUST ENOUGH
TO FORECAST LAND WIND GUSTS IN EXCESS OF 30 MPH, BUT MODEL
SOUNDINGS AREN`T PRESENTLY SHOWING A WIND ADVISORY LEVEL FLOW. THE
SECONDARY IMPULSE ALSO CARRIES SOME LESSER PRESSURE RISES IN ITS
WAKE. THE SOUNDINGS ACROSS THE NORTH ARE CAPPED AT ABOUT 7000 FT
AND WE CARRY A CYCLONIC SURFACE FLOW SUNDAY INTO SUNDAY NIGHT, SO
WE CONTINUE TO CARRY FLURRIES NORTH DURING THIS TIME FRAME.
THE MODELS THEN AGREE TO TAKE A MID LEVEL IMPULSE ACROSS THE AREA IN
THE TUESDAY TO WEDNESDAY TIME FRAME, AND THEN START TO DIVERGE ON
THE HANDLING OF ANOTHER AND POSSIBLY MORE ROBUST SYSTEM TOWARD THE
END OF THE WORK WEEK. WE MADE MODEST CHANGES WITH RESPECT TO THE
FORMER AND FOLLOWED CONTINUITY WITH RESPECT TO THE LATTER.
TEMPERATURES WILL START OFF BELOW NORMAL EARLY THIS PERIOD,
TRANSITION TO NORMAL EARLY IN THE WORK WEEK AND THEN GO ABOVE
NORMAL FOR THE LATTER PART OF THE PERIOD.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
VARYING CONDITIONS EARLY THIS AFTERNOON WERE SLOWING IMPROVING AS
THE PRECIPITATION ENDS FROM WEST TO EAST. HOWEVER...MOISTURE REMAINS
TRAPPED UNDER THE INVERSION. A RECENT AMDAR SOUNDING FROM KPHL
SUGGESTS THAT THE INVERSION MAY BE READY TO BREAK...AND MVFR
CONDITIONS SHOULD BE THE RULE THROUGH 2200 UTC.
AN ARCTIC FRONT WILL CROSS THE REGION THIS EVENING...CENTERED AROUND
0000 UTC. FOR THE MOST PART...MVFR CONDITIONS HAVE BEEN ACCOMPANYING
THE FRONTAL PASSAGE ACROSS WESTERN AND CENTRAL PENNSYLVANIA.
THUS...MVFR CONDITIONS ARE FORECAST BETWEEN 0000 UTC AND 0400
UTC...WITH THE LOWEST CONDITIONS FROM KPHL SOUTH.
AFTER THE FRONT PASSES AND THE INVERSION ASSOCIATED WITH THE FRONT
INCREASES...VFR CONDITIONS SHOULD RETURN AFTER 0600 UTC SUNDAY.
HOWEVER...THE GRADIENT BEHIND THE ARCTIC FRONT TIGHTENS FAIRLY
QUICKLY...AND SHOULD EASILY SUPPORT SUSTAINED WINDS BETWEEN 17 AND
22 KNOTS ACROSS THE BOARD. MODEL SOUNDINGS SUGGEST THAT WINDS WILL
RANGE BETWEEN 35 AND 41 KNOTS AT THE TOP OF THE INVERSION DURING THE
BEST OF THE COLD AIR ADVECTION...SO GUSTS TO 35 KNOTS ARE EXPECTED
DURING THE OVERNIGHT HOURS...WITH THE STRONGEST GUSTS FROM KPHL
SOUTH.
VFR CEILINGS COULD BREAK FOR A TIME LATER TONIGHT AND SUNDAY
MORNING. THE NEW AIRMASS HAS FAIRLY LOW CONVECTIVE TEMPERATURES
ASSOCIATED WITH IT...SO SUNSHINE WILL BE SELF DESTRUCTIVE...ALLOWING
CUMULUS/STRATOCUMULUS TO DEVELOP. THE GRADIENT CONTINUES TO SUPPORT
SUSTAINED WINDS BETWEEN 18 AND 25 KNOTS FOR THE REMAINDER OF THE
DAY...AFTER A BRIEF LULL NEAR SUNRISE. MODEL SOUNDINGS SUGGEST THAT
THE GUST POTENTIAL IS NOT QUITE AS HIGH AS TONIGHT...AS THE MOMENTUM
TRANSFER IS NOT AS EFFICIENT AS TONIGHT.
OUTLOOK...
OUTSIDE OF ANY SNOW SHOWER ACTIVITY THAT MAY OCCUR ON SUNDAY INTO
SUNDAY EVENING (ESPECIALLY NORTHWEST), WE EXPECT VFR CONDITIONS INTO
TUESDAY. THE WEAK WEATHER SYSTEM DURING THE MIDWEEK PERIOD MAY CAUSE
SOME DETERIORATION IN CONDITIONS.
&&
.MARINE...
WE WILL CONVERT THE GALE WATCH TO A WARNING AND EXTEND IT OUT UNTIL
06Z MONDAY.
LOW PRESSURE WILL DEEPEN OFF THE EAST COAST AND TRACK WELL TO OUR
EAST TODAY THROUGH SUNDAY. THE GRADIENT OVER THE WATERS WILL NOT BE
VERY STRONG TODAY...BUT WILL STRENGTHEN SIGNIFICANTLY LATER TODAY
AND REMAIN STRONG INTO EARLY NEXT WEEK. A COLD FRONT WILL CROSS THE
WATERS THIS EVENING AND THE STRONG WIND GUSTS WILL FOLLOW IT. GUSTS
TO 40 KTS ARE POSSIBLE. SCATTERED SNOW SHOWERS WITH LOWER VSBYS MAY
ACCOMPANY THE FRONT. GUSTY WINDS AND ENHANCED SEAS WILL CONTINUE
THROUGH TONIGHT.
GALES ARE EXPECTED TO LAST INTO SUNDAY, AND THEY MAY LINGER INTO
SUNDAY EVENING WITH A SECONDARY FRONT CROSSING THE AREA. AFTER
THAT, CONDITIONS SHOULD DROP TO SUB-ADVISORY AND REMAIN SO THROUGH
THE MIDDLE OF THE WEEK.
&&
.TIDES/COASTAL FLOODING...
NONE OF THE LATEST OFS PROGS ARE TAKING ANY OF THE REFERENCE GAUGES
TO WITHIN A HALF FOOT OF THE MINOR TIDAL FLOODING BENCHMARKS. NO
DEPARTURES THIS MORNING WERE MUCH IN EXCESS OF 0.5 FT. WE WILL
CONTINUE TO MONITOR TIDES IN THE EVENT THAT THE PROGS ARE UNDERDONE,
BUT ANY THREAT OF MINOR TIDAL FLOODING WILL DIMINISH ONCE WINDS COME
AROUND TO NORTHWEST. WE THEN WILL TURN OUR CONCERN TO THE POSSIBILITY
OF BLOWOUT TIDES, WHICH ALSO IS DOWNPLAYED BY OFS PROGS.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...GALE WARNING FROM 6 PM THIS EVENING TO 1 AM EST MONDAY FOR
NJZ025-026.
DE...NONE.
MD...NONE.
MARINE...GALE WARNING FROM 6 PM THIS EVENING TO 1 AM EST MONDAY FOR
ANZ430-431-450>455.
&&
$$
SYNOPSIS...DELISI
NEAR TERM...HAYES
SHORT TERM...O`HARA
LONG TERM...DELISI/KRUZDLO
AVIATION...DELISI/HAYES
MARINE...DELISI/O`HARA
TIDES/COASTAL FLOODING...DELISI
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1045 AM CST SAT FEB 11 2012
.DISCUSSION...
ISSUED 1045 AM CST SAT FEB 11 2012
FORECAST GENERALLY LOOKS ON TRACK TODAY AND ONLY MINOR ADJUSTMENTS
TO THE HOURLY WEATHER ELEMENTS LIKE BUMPING UP THE WIND SPEEDS A
TAD. BLUSTERY NW WINDS OF 15 TO 25 MPH AND GUSTS OF 25 TO 35 MPH
ARE EXPECTED TODAY. HIGHS MOSTLY IN THE LOWER 20S...WITH
LAWRENCEVILLE NEAR 25F. A 1 TO 2.5 INCH SNOW COVER ALONG AND WEST
OF A MACOMB TO JACKSONVILLE LINE WILL KEEP THAT AREA A BIT COOLER
ESPECIALLY FOR LOWS TONIGHT. ALSO A LIGHT SNOW COVER LESS THAN 1
INCH FROM BLOOMINGTON TO OLNEY EAST WILL ALSO KEEP THEM A BIT
COOLER ESPECIALLY TONIGHT. NAM AND GFS BUFKIT MOMENTUM SHOWS GUSTS
IN THE UPPER 20S AND LOWER 30S KNOTS RANGE TODAY INTO EARLY
EVENING AND DROP OFF BY MID EVENING. AMPLE SUNSHINE TO PREVAIL
TODAY WITH JUST FEW TO SCATTERED CUMULUS CLOUDS EXPECTED OVER
EASTERN IL WHERE MOSTLY SUNNY SKIES EXPECTED AND THESE CLOUDS HAVE
JUST RECENTLY DEVELOPED BY LATE MORNING.
WIND CHILLS CURRENTLY IN THE SINGLE DIGITS ABOVE ZERO...EXCEPT
ZERO TO 5 BELOW ZERO FROM BLOOMINGTON TO CHAMPAIGN NE WILL MOSTLY
STAY IN THE SINGLE DIGITS TODAY...SO WILL FEEL LIKE ONE OF THE
COLDER DAYS SO FAR DURING THIS RELATIVELY MILD WINTER OVER CENTRAL
IL. STRONG 1046 MB ARCTIC HIGH PRESSURE OVER THE CENTRAL PLAINS
EDGE CLOSER TO THE MS VALLEY THROUGH SUNDAY MORNING AND KEEP IL
DRY AND COLD THIS WEEKEND.
HUETTL
&&
.AVIATION...
ISSUED 525 AM CST SAT FEB 11 2012
STRONG HIGH PRESSURE CENTERED IN SOUTH DAKOTA WILL BE THE MAIN
WEATHER INFLUENCE IN CENTRAL AND EASTERN IL TODAY AND SUNDAY.
PLENTY OF SUBSIDENCE AND DRY AIR WILL RESULT IN VFR CONDITIONS THE
NEXT 24 HOURS. WILL GO WITH A CLEAR SKY AT ALL TAF SITES AS A
RESULT. THE RUC WAS TRYING TO INDICATE SOME SCT-BKN CU NEAR KCMI
AND POINTS EAST FROM LAKE MICHIGAN LATE THIS MORNING. HOWEVER THE
FETCH DOWN THE LAKE SHOULD BECOME MORE NORTH-NORTHWESTERLY...WHICH
WOULD KEEP ANY CLOUDS EAST OF THE AREA.
THE WIND HAS RELAXED A LITTLE BIT IN PARTS OF CENTRAL IL EARLY
THIS MORNING...DESPITE A CONTINUED TIGHT PRESSURE GRADIENT. I
EXPECT THIS TO INCREASE AGAIN BY LATE MORNING AS THE LOWER
ATMOSPHERE STARTS TO MIX. BUFKIT SOUNDINGS AND MOMENTUM TRANSFER
POINT TO GUSTS IN THE 20-28KT RANGE TODAY...SO WILL FOLLOW THAT
GUIDANCE CLOSELY.
MILLER
&&
.PREV DISCUSSION...
ISSUED 322 AM CST SAT FEB 11 2012
COLD AIR MOVING INTO THE REGION BEHIND A FRONTAL SYSTEM AND A DEEP
UPPER TROF...FINALLY BRINGING SOME COLDER AND MORE SEASONABLE TEMPS
INTO THE MIDWEST FOR THE WEEKEND. HIGH PRESSURE BUILDING IN OVER
THE NORTHERN PLAINS...AND CLEARING SKIES SCOURING OUT THE REMNANT
FLURRIES OVER ILX. MAIN ISSUES FOR THE FORECAST REVOLVE AROUND THE
NEXT SYSTEM ON APPROACH FOR MON/TUES. SOME MINOR TIMING ISSUES
AFFECT THE ONSET OF SNOW ON MONDAY...BUT THE ABUNDANCE OF COLD AIR HAS
EFFECTIVELY REMOVED MOST CONCERNS ABOUT PRECIP TYPE. FORECAST
REMAINS A SLIGHT BLEND...BUT MOST OF THE PARAMETERS ARE IN
RELATIVE AGREEMENT. NEXT ISSUES IN THE FORECAST WILL BE THE TEMPS
ON THE OTHER SIDE OF THE SNOW AT THE END OF THE WORK WEEK. MOS
NUMBERS LOOK A LITTLE TOO WARM CONSIDERING ANOTHER SHOT OF COLD
AIR MOVING IN AT MID LEVELS.
SHORT TERM...TODAY AND TOMORROW...
COLD. TEMPS CHILLY THIS MORNING IN THE TEENS ACROSS CENTRAL
ILLINOIS...AND BRISK NORTHERLY FLOW WILL KEEP THE HIGHS
CONSIDERABLY COOLER...HIGHS ONLY CLIMBING INTO THE
20S...REGARDLESS OF AMPLE SUNSHINE. SAME CONTINUES TONIGHT...WITH
CLEAR SKIES AND AN ARCTIC AIRMASS PUSHING THE TEMPS DOWN INTO THE
SINGLE DIGITS AND AROUND 10F. HIGH PRESSURE RIDGE SHIFTS ENOUGH TO
BRING WINDS TO A MORE WESTERLY DIRECTION FOR TOMORROW...AND TEMPS
WILL CLIMB BACK UP TO UPPER 20S...AND DROP INTO THE TEENS SUN
NIGHT IN ADVANCE OF THE CLOUDS ASSOCIATED WITH THE NEXT DEVELOPING
SYSTEM MOVING OUT OF THE WEST.
LONG TERM...MONDAY THROUGH FRIDAY...
WAVE MOVING INTO THE PAC NW WILL PUSH OVER THE ROCKIES AND INTO
THE MIDWEST MID-MONDAY AND BRING THE NEXT CHANCE FOR SNOW. MODELS
IN ENOUGH ARGUMENT TO GO CATEGORICAL AT THIS POINT...WITH THE GFS
JUST SLIGHTLY AHEAD...BRINGING IN THE SNOW ACROSS THE WRN HALF OF
THE CWA BY NOON. BETTER CHANCES STILL LATER MONDAY AFTERNOON AND
MON EVENING INTO THE OVERNIGHT. HPC AND PREV FORECAST RATHER
CONSISTENT IN THE 1 TO 2 INCH STORM TOTALS. SLR AROUND 13
CONSISTENT WITH CLIMATOLOGY...AND FORECAST SOUNDINGS ACROSS THE
BOARD SHOWING PLENTY OF MOISTURE TO WORK WITH THROUGHOUT THE
COLUMN MON LATE AFTERNOON. SNOW TAPERING OFF DURING THE DAY ON
TUESDAY. ANOTHER SYSTEM QUICK ON ITS HEELS MOVING OUT OF THE
ROCKIES EARLY THU. CURIOUS AGREEMENT IN THE EXTENDED BTWN THE GFS
AND THE ECMWF...AND POPS WILL COME UP IF THE AGREEMENT
CONTINUES...EVEN AT DAY 6. HOWEVER...THE TRACK OF THE GFS IS A BIT
FURTHER SOUTH WHICH WOULD MAKE A RATHER SIG DIFFERENCE FOR AREAS
NORTH OF ILLINOIS RIVER VALLEY AS FAR AS IMPACT. TEMPS FOR THU AND
FRI A BIT WARM AT THIS POINT. CONCERNED THAT THE ECMWF IS BRINGING
THROUGH SOME RATHER COLD AIR AT MID LEVELS AND PLENTY OF
CLOUDS...NOT CONVINCED THAT THE SFC TEMPS WILL GET THAT WARM AND
HAVE PULLED THEM DOWN SLIGHTLY. THIS MISREPRESENTATION WILL DEF
HAVE IMPACT ON THE PRECIP TYPE. NOT SUPER CONFIDENT JUST YET IN
THE EXTENDED.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
112 PM EST SAT FEB 11 2012
.AVIATION /18 UTC TAFS/...
LES EVENT BEGINNING TO WANE AS UPSTREAM WITHIN CLOUD SHEAR INCRS.
OVERALL STEERING FLOW CONTS TO BACK DRAWING MUCH DRIER AIR INTO
SYSTEM...SQUELCHING VERTICAL EXTENT OF CONVECTION. KSBN SHOULD BE
IN FINAL HOURS OF LIFR POTNL AT KSBN BEFORE MUCH IMPROVED CONDS
BYND 20 UTC. STRONG WINDS AND MORE CELLULAR SHSN COULD STILL LEAD
TO HIGHLY VARIABLE VSBYS THEREAFTER INTO THE EVENING HOURS BEFORE
ENDING. FURTHER INLAND AT KFWA SERN TERMINUS OF LES BANDS SHOULD
SKIRT IN/OUT OF VCNTY INTO MID AFTN...THOUGH OVERALL IMPACT QUITE
MARGINAL/BRIEF AND KEPT TEMPO GROUP ABOVE FUEL ALT REQRMNTS.
CLEARING SKIES AND WINDS RELAX AS SUBSIDENCE INVERSION
STRENGTHENS.
&&
.PREV DISCUSSION... /ISSUED 423 AM EST SAT FEB 11 2012/
SHORT TERM.../TODAY THROUGH SUNDAY NIGHT/
..LAKE EFFECT SNOW EVENT UNDERWAY...
ARCTIC COLD FRONT HAS SWEPT ACROSS THE FORECAST AREA WITH
TEMPERATURES IN THE TEENS AND DEWPTS FALLING INTO THE SINGLE DIGITS.
SOME LEFTOVER LIGHT SNOW WAS SEEN ON OBS AND RADAR ACROSS PORTIONS
OF NORTHEASTERN INDIANA AND NORTHWESTERN OHIO. MAIN FOCUS WAS WELL
DEFINED INTENSE LAKE EFFECT SNOW BAND THAT RAPIDLY DEVELOPED ACROSS
LAKE AND PORTER COUNTIES THIS PAST EVENING AND AFTER A BRIEF SHIFT
WEST AND INCREASE IN EASTERN PROGRESS HAS BEEN NOTED WITH THE BAND
CURRENTLY SITUATED ACROSS LAPORTE AND STARKE COUNTIES AHEAD OF
SCHEDULE. REPORT FROM VALPO UNIV OF LIGHTNING WAS RECEIVED AS THE
HEAVIEST PART OF THE BAND SHIFTED ACROSS THAT AREA. RADAR TRENDS
ACROSS THE FORECAST AREA HAS SHOWN A DOWNWARD TREND IN SOUTHERN
EXTENT AND INTENSITY OF THE BAND. UPSTREAM ACROSS THE LAKE KGRR
RADAR SHOWING AN INCREASE IN RETURNS AS THE BAND SHIFTED MORE ALONG
THE EASTERN SHORE OF THE LAKE. A FEW RUNS OF THE HRRR SUGGESTED THIS
MAY OCCUR WITH THE INITIAL BAND WEAKENING WITH TIME AS CONVERGENCE
WEAKENED AND MORE OF A MULTI BAND SETUP BEGAN TO ESTABLISH WITH TIME
THIS MORNING. WHILE FULL WARNING CRITERIA MAY NOT BE
MET...DETERIORATING CONDITIONS STILL WARRANT HOLDING ONTO CURRENT
HEADLINES. RISK FOR WARNING CRITERIA STILL POSSIBLE OVER BERRIEN
COUNTY AS BAND REORIENTS AND PERSISTS INTO EARLY AFTERNOON. DID
EXPAND POPS FURTHER SOUTH AND EAST AS INLAND EXTENT OF BANDS MAY
INCREASE AS OVERALL FLOW INCREASES SOMEWHAT WITH STRONGER GRADIENT
SHIFTING ACROSS THE AREA. WOULD NOT EXPECT MUCH IMPACT BUT FELT AT
LEAST CHC POPS WERE NEEDED DOWNSTREAM OF THE BAND.
GIVEN UNCERTAINTY OF EXTENT AND INTENSITY OF HEAVIEST BANDS HAVE
WENT WITH LIKELY POPS INTO THE AFTERNOON WITH ONLY LIGHT ADDITIONAL
ACCUMS.
NW FLOW WILL PERSIST ACROSS THE REGION INTO SUNDAY. HOWEVER...LL
TEMPS WILL QUICKLY UNDERGO MODERATION TONIGHT INTO SUNDAY CAUSING
DELTA T`S TO DECREASE AND INVERSION HGTS TO LOWER. THE RESULT WILL
BE SOME LINGERING VERY LIGHT SNOW OR FLURRIES INTO TONIGHT BEFORE
ENDING. SUNDAY/SUNDAY NIGHT APPEAR DRY AT THIS POINT WITH HIGH
PRESSURE BUILDING IN. MEAN RH VALUES DROPS CONSIDERABLY BY SUNDAY
AFTERNOON INTO SUNDAY NIGHT...ALLOWING FOR MOSTLY CLEAR TO CLEAR
SKIES AND MODERATING TEMPS.
LONG TERM...MONDAY THROUGH FRIDAY
OVERALL VERY FEW CHANGES REQUIRED TO THE LONG TERM PERIOD FOR THIS
FORECAST CYCLE.
FOR MONDAY...LOW LEVEL ANTICYCLONE WILL SHIFT EASTWARD THROUGH THE
LOWER MS RIVER VALLEY INTO THE SOUTHEAST US...EVENTUALLY ALLOWING
LOW LEVEL RETURN SOUTHWESTERLY FLOW TO SETUP. A SHEARED UPPER VORT
MAX DIVORCED FROM STRONGER STEERING FLOW AS A RESULT OF WESTERN
CONUS SPLIT FLOW SHOULD GRADUALLY GET PHASED WITH A MORE AMPLIFIED
SOUTHERN STREAM TROUGH KICKING OUT OF THE FOUR CORNERS REGION. AS
THIS OCCURS...STRONGER LOW LEVEL THETAE ADVECTION/ISENTROPIC LIFT
SHOULD BE FOCUSED JUST WEST OF THE AREA. NAM/GFS ISENTROPIC PROGS IN
290-280K LAYER DO INDICATE MORE SUBSTANTIAL LOWERING OF
CONDENSATIONAL PRESSURE DEFICITS THROUGHOUT THIS LAYER BY LATE IN
THE DAY MONDAY...BUT SUBCLOUD LAYER MAY BE TOO DRY FOR MOST AREAS TO
RECEIVE ANY PRECIP MONDAY AFTERNOON. A SHARP LOW LEVEL GRADIENT
NOTED IN MIXING RATIOS THROUGHOUT THIS LAYER FROM WEST TO EAST ON
MONDAY...AND PREVIOUS POP GRADIENT MONDAY AFTERNOON FROM LOW CHANCE
WEST TO SLIGHT CHANCE EAST STILL APPEARS REASONABLE. STRONGER
ISENTROPIC UPGLIDE AND MID LEVEL FORCING TO MOVE IN FOR MONDAY NIGHT
WHICH STILL APPEARS TO BE SHAPING UP AS A HIGH POP/LOW QPF EVENT
BASED ON A RELATIVELY SHORT DURATION OF BETTER LOW/MID LEVEL
MOISTURE PROFILES AND RATHER DISJOINTED NATURE OF MID/UPPER LEVEL
FORCING WITH ONLY PARTIAL PHASING OF THESE AFOREMENTIONED SHORT
WAVES. MOST OF PRECIP EXPECTED MONDAY NIGHT BUT WILL CONTINUE TO
CARRY CHANCE -SN MENTION INTO TUESDAY WITH LAGGING SHORT WAVE SLOW
TO EXIT THE AREA. PRECIP MAY END AS A PERIOD OF DRIZZLE/FLURRIES
TUESDAY NIGHT...ESPECIALLY ACROSS EASTERN AREAS...AS MOISTURE
PROFILES BECOMING INCREASING SHALLOW WITH ONLY WEAK MID LEVEL
FORCING.
MEDIUM RANGE MODELS HAVE STARTED TO CONVERGE A BIT MORE IN REGARDS
TO MID/LATE WEEK SYSTEM WITH ECMWF EXHIBITING SOME BETTER RUN TO RUN
CONTINUITY IN COMPARISON TO 24 HOURS AGO. FLOW PATTERN QUITE COMPLEX
FOR THIS PERIOD WITH MAIN QUESTION REGARDING PHASING ISSUES OF NEXT
SOUTHERN STEAM UPPER TROUGH WITH ACTIVE SOUTHERN CANADIAN NORTHERN
STREAM. GENERALLY FOLLOWED HPC PREFERENCE OF A SLIGHTLY SLOWER THAN
ECMWF SOLUTION GIVEN EXPECTED FAST BIASED EJECTION OF SOUTHWEST US
WAVE. THIS CENTERS HIGHEST POPS IN THE THURS NIGHT PERIOD BUT
DEPENDING ON RATE OF EJECTION OF THIS TROUGH...PRECIP MAY EVENTUALLY
HAVE TO BE ADDED INTO FRIDAY. HARD TO DEVIATE AT THIS TIME FROM A
BROADBRUSH RAIN/SNOW PTYPE MENTION FOR THURSDAY/THURSDAY NIGHT GIVEN
EXPECTED MARGINAL LOW LEVEL THERMAL PROFILES DURING THIS PERIOD.
TEMPS SHOULD TREND SLIGHTLY ABOVE SEASONABLE NORMS FOR THE WED-FRI
PERIOD WITH SOME SUGGESTIONS OF A BRIEF SHOT OF COLD ADVECTION
TOWARD THE END OF THE PERIOD AS LARGER SCALE NORTHERN STREAM TROUGH
DIGS ACROSS THE GREAT LAKES REGION.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS EVENING FOR INZ004-
014.
MI...WINTER STORM WARNING UNTIL 6 PM EST THIS EVENING FOR MIZ077.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 7 AM EST MONDAY FOR LMZ043-046.
&&
$$
SHORT TERM...FISHER
LONG TERM...MARSILI
AVIATION...MURPHY
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
554 PM EST SAT FEB 11 2012
.SYNOPSIS...
BLUSTERY NORTHWEST WINDS WILL MAINTAIN SNOW SHOWERS AND BLOWING
SNOW INTO EARLY SUNDAY MORNING, AND CAUSE SUBZERO WIND CHILL.
INCOMING MIDWEST HIGH PRESSURE WILL PROVIDE MODERATING TEMPERATURES
MONDAY AFTERNOON.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
WILL ALLOW ADVISORY FOR ZANESVILLE AREA TO EXPIRE AS MAIN BANDS OF
SNOW ARE EAST OF THAT REGION. MAIN BAND OF HEAVY SNOW CONTINUES
FROM COLUMBIANA COUNTY TO NEAR STEUBENVILLE AND SOUTH ACROSS
WASHINGTON COUNTY AND INTO THE RIDGES. THIS BAND HAS PRODUCED
RATES OVER AN INCH AN HOUR LAST 3-4 HOURS BUT IS BEGINNING TO
BREAK DOWN AS SHORTWAVE BEGINNING TO MOVE SOUTH ACROSS EASTERN
LAKES APPROACHES TO DISTURB FLOW. BANDS WILL CONTINUE ACROSS
GREATER PITTSBURGH REGION BEFORE DIMINISHING FOR A TIME LATE
EVENING AHEAD OF SHORTWAVE. PREVIOUS POPS SEEM IN LINE OVERALL.
PREVIOUS DISCUSSION FOLLOWS.
PER BLEND OF RECENT SURFACE AND RADAR DATA COUPLED WITH HRRR AND
NAM MODEL OUTPUT, EXPECT COLD BLUSTERY NORTHWEST WINDS TO PROVIDE
SNOW SHOWERS AND BLOWING SNOW FOR THE UPPER OHIO VALLEY EAST OF
THE OHIO LINE INTO EARLY SUNDAY MORNING. SO HAVE MAINTAINED THE
WINTER WEATHER HEADLINES.
WIND GUSTS ACROSS THE HIGHER MOUNTAINS CAN APPROACH 45 MPH,
ELSEWHERE 35-40 MPH. WITH TEMPERATURES IN THE TEENS, EXPECT WIND
CHILLS TO GO SUBZERO. ACROSS THE HIGHER MOUNTAINS, WIND CHILL CAN
GO TO MINUS 15, SO HAVE ADDED WIND CHILL ADVISORY THERE THROUGH
SUNDAY MORNING.
REGARDING SNOW SHOWER DETAILS, RECENT WRF-NMM AND HRRR SHOW THE
LAKE EFFECT SNOW BANDS SHIFTING SOUTH. ALSO NAM MODEL PROFILES
SHOW THE SUBSIDENCE INVERSION CAN LOWER, SO SNOW SHOWER INTENSITY
SHOULD DECREASE LATE TONIGHT. HOWEVER KEPT SNOW SHOWERS ACROSS THE
HIGHER ELEVATIONS, AS OROGRAPHIC INFLUENCES SOMETIMES MAINTAIN
SNOW SHOWERS LONGER THEN EXPECTED.
TEMPERATURE AND WIND DETAILS WERE BASED ON CONSENSUS OF GFS LAMP
AND NAM MODEL OUTPUT.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY/...
RECENT NAM AND GFS MODEL OUTPUT SHOW HIGH PRESSURE PROVIDING DRY
CONDITIONS SUNDAY NIGHT INTO MONDAY NIGHT. TEMPERATURES WILL STILL
BE QUITE COLD INTO MONDAY MORNING, BUT THEN MODERATE TO WITHIN 5
DEGREES OF NORMAL MONDAY AFTERNOON.
MODELS THEN SHOW A WEAK LOW PRESSURE SYSTEM, COMING EAST FROM THE
PLAINS TO PROVIDE MIX OF SNOW AND RAIN SHOWERS TUESDAY, WITH
TEMPERATURES TUESDAY AFTERNOON NEAR NORMAL.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
GENERALLY FOLLOWED EC AND HPC GUIDANCE. HIGH PRESSURE ACROSS REGION
WEDNESDAY WITH FAIR WEATHER. MODELS CONTINUE TO STRUGGLE WITH
STRENGTH OF LOW PRESSURE MOVING THROUGH OHIO RIVER VALLEY ON
THURSDAY...BUT EXPECT MOSTLY RAIN ON THURSDAY WITH SOME SNOW
POSSIBLE ACROSS FAR NORTH. BY FRIDAY SYSTEM IS WELL EAST OF AREA
WITH CHANCE OF SNOW SHOWERS IN NORTHWEST FLOW. HIGH PRESSURE
REMAINS WEST OF REGION WITH NORTHWEST FLOW. THIS SHOULD KEEP SOME
CLOUDINESS OF REGION...BUT LACK OF COLD AIR PRECLUDES SNOW SHOWER
ACTIVITY SATURDAY.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
COLD FRONT EAST OF CWA. THROUGH 12/00Z GENERAL CIGS 015-025 AND VSBY
2-4 MILES WITH CONDS LOWERING TO CIG 005 VSBY 3/4-1 MILE IN HEAVIER
SNOW BANDS.
MODELS SHOW SOME DRYING EARLY TONIGHT WITH ANOTHER BAND OF DEEPER
MOISTURE RETURNING AFTER MIDNIGHT. RAISED CONDITIONS TO MVFR AFTER
00Z THROUGH 06Z...THEN LOWERED TO IFR AFTER 07Z. LOWERING INVERSION
LAYER WILL CRUSH CONVECTION AFTER 15Z SUNDAY WITH CONDITIONS
BECOMING MVFR TO VFR.
OUTLOOK...MONDAY THROUGH THURSDAY...
BUILDING HIGH PRESSURE WILL RETURN BY MONDAY WITH VFR CONDITIONS.
SHORTWAVE IN ZONAL FLOW IS PROGGED TO GENERATE MORE LIGHT SNOW BY
EARLY TUESDAY. AT LEAST MVFR CAN BE EXPECTED WITH THAT SYSTEM.
REBUILDING HIGH PRESSURE WILL RETURN VFR BY LATE TUESDAY AND
WEDNESDAY.
STRONGER SYSTEM MOVES THROUGH REGION ON THURSDAY WITH LOW PASSING
WEST OF CWA. RAIN REACHING WESTERN TERMINALS THURSDAY MORNING AND
SPREADING ACROSS REGION BY AFTERNOON. CONDITIONS DETERIORATING TO
MVFR IN MOSTLY RAIN. SOME SNOW OR RAIN AND SNOW POSSIBLE AT NORTHERN
TERMINALS.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER STORM WARNING UNTIL 6 AM EST SUNDAY FOR MDZ001.
WIND CHILL ADVISORY UNTIL NOON EST SUNDAY FOR MDZ001.
OH...WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS EVENING FOR OHZ039-
048-057-058-068.
WINTER WEATHER ADVISORY UNTIL 6 AM EST SUNDAY FOR OHZ040-041-
049-050-059-069.
PA...WINTER WEATHER ADVISORY UNTIL 6 AM EST SUNDAY FOR PAZ007>009-
013>016-020>023-029-031-073-075.
WINTER STORM WARNING UNTIL 6 AM EST SUNDAY FOR PAZ074-076.
WIND CHILL ADVISORY UNTIL NOON EST SUNDAY FOR PAZ074-076.
WV...WINTER WEATHER ADVISORY UNTIL 6 AM EST SUNDAY FOR WVZ001>004-
012-021-022.
WINTER STORM WARNING UNTIL 6 AM EST SUNDAY FOR WVZ023-041.
WIND CHILL ADVISORY UNTIL NOON EST SUNDAY FOR WVZ023-041.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
359 PM EST SAT FEB 11 2012
.SYNOPSIS...
BLUSTERY NORTHWEST WINDS WILL MAINTAIN SNOW SHOWERS AND BLOWING
SNOW INTO EARLY SUNDAY MORNING, AND CAUSE SUBZERO WIND CHILL.
INCOMING MIDWEST HIGH PRESSURE WILL PROVIDE MODERATING TEMPERATURE
MONDAY AFTERNOON.
&&
.NEAR TERM /UNTIL 6 PM SUNDAY/...
PER BLEND OF RECENT SURFACE AND RADAR DATA COUPLED WITH HRRR AND
NAM MODEL OUTPUT, EXPECT COLD BLUSTERY NORTHWEST WINDS TO PROVIDE
SNOW SHOWERS AND BLOWING SNOW FOR THE UPPER OHIO VALLEY EAST OF
THE OHIO LINE INTO EARLY SUNDAY MORNING. SO HAVE MAINTAINED THE
WINTER WEATHER HEADLINES.
WIND GUSTS ACROSS THE HIGHER MOUNTAINS CAN APPROACH 45 MPH,
ELSEWHERE 35-40 MPH. WITH TEMPERATURES IN THE TEENS, EXPECT WIND
CHILLS TO GO SUBZERO. ACROSS THE HIGHER MOUNTAINS, WIND CHILL CAN
GO TO MINUS 15, SO HAVE ADDED WIND CHILL ADVISORY THERE THROUGH
SUNDAY MORNING.
REGARDING SNOW SHOWER DETAILS, RECENT WRF-NMM AND HRRR SHOW THE
LAKE EFFECT SNOW BANDS SHIFTING SOUTH. ALSO NAM MODEL PROFILES
SHOW THE SUBSIDENCE INVERSION CAN LOWER, SO SNOW SHOWER INTENSITY
SHOULD DECREASE LATE TONIGHT. HOWEVER KEPT SNOW SHOWERS ACROSS THE
HIGHER ELEVATIONS, AS OROGRAPHIC INFLUENCES SOMETIMES MAINTAIN
SNOW SHOWERS LONGER THEN EXPECTED.
TEMPERATURE AND WIND DETAILS WERE BASED ON CONSENSUS OF GFS LAMP
AND NAM MODEL OUTPUT.
&&
.SHORT TERM /SUNDAY EVENING THROUGH TUESDAY/...
RECENT NAM AND GFS MODEL OUTPUT SHOW HIGH PRESSURE PROVIDING DRY
CONDITIONS SUNDAY NIGHT INTO MONDAY NIGHT. TEMPERATURES WILL STILL
BE QUITE COLD INTO MONDAY MORNING, BUT THEN MODERATE TO WITHIN 5
DEGREES OF NORMAL MONDAY AFTERNOON.
MODELS THEN SHOW A WEAK LOW PRESSURE SYSTEM, COMING EAST FROM THE
PLAINS TO PROVIDE MIX OF SNOW AND RAIN SHOWERS TUESDAY, WITH
TEMPERATURES TUESDAY AFTERNOON NEAR NORMAL.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
GENERALLY FOLLOWED EC AND HPC GUIDANCE. HIGH PRESSURE ACROSS REGION
WEDNESDAY WITH FAIR WEATHER. MODELS CONTINUE TO STRUGGLE WITH
STRENGTH OF LOW PRESSURE MOVING THROUGH OHIO RIVER VALLEY ON
THURSDAY...BUT EXPECT MOSTLY RAIN ON THURSDAY WITH SOME SNOW
POSSIBLE ACROSS FAR NORTH. BY FRIDAY SYSTEM IS WELL EAST OF AREA
WITH CHANCE OF SNOW SHOWERS IN NORTHWEST FLOW. HIGH PRESSURE
REMAINS WEST OF REGION WITH NORTHWEST FLOW. THIS SHOULD KEEP SOME
CLOUDINESS OF REGION...BUT LACK OF COLD AIR PRECLUDES SNOW SHOWER
ACTIVITY SATURDAY.
&&
.AVIATION /21Z SATURDAY THROUGH THURSDAY/...
COLD FRONT EAST OF CWA. THROUGH 12/00Z GENERAL CIGS 015-025 AND VSBY
2-4 MILES WITH CONDS LOWERING TO CIG 005 VSBY 3/4-1 MILE IN HEAVIER
SNOW BANDS.
MODELS SHOW SOME DRYING EARLY TONIGHT WITH ANOTHER BAND OF DEEPER
MOISTURE RETURNING AFTER MIDNIGHT. RAISED CONDITIONS TO MVFR AFTER
00Z THROUGH 06Z...THEN LOWERED TO IFR AFTER 07Z. LOWERING INVERSION
LAYER WILL CRUSH CONVECTION AFTER 15Z SUNDAY WITH CONDITIONS
BECOMING MVFR TO VFR.
OUTLOOK...MONDAY THROUGH THURSDAY...
BUILDING HIGH PRESSURE WILL RETURN BY MONDAY WITH VFR CONDITIONS.
SHORTWAVE IN ZONAL FLOW IS PROGGED TO GENERATE MORE LIGHT SNOW BY
EARLY TUESDAY. AT LEAST MVFR CAN BE EXPECTED WITH THAT SYSTEM.
REBUILDING HIGH PRESSURE WILL RETURN VFR BY LATE TUESDAY AND
WEDNESDAY.
STRONGER SYSTEM MOVES THROUGH REGION ON THURSDAY WITH LOW PASSING
WEST OF CWA. RAIN REACHING WESTERN TERMINALS THURSDAY MORNING AND
SPREADING ACROSS REGION BY AFTERNOON. CONDITIONS DETERIORATING TO
MVFR IN MOSTLY RAIN. SOME SNOW OR RAIN AND SNOW POSSIBLE AT NORTHERN
TERMINALS.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER STORM WARNING UNTIL 6 AM EST SUNDAY FOR MDZ001.
WIND CHILL ADVISORY UNTIL NOON EST SUNDAY FOR MDZ001.
OH...WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS EVENING FOR OHZ039-
048-057-058-068.
WINTER WEATHER ADVISORY UNTIL 6 AM EST SUNDAY FOR OHZ040-041-
049-050-059-069.
PA...WINTER WEATHER ADVISORY UNTIL 6 AM EST SUNDAY FOR PAZ007>009-
013>016-020>023-029-031-073-075.
WINTER STORM WARNING UNTIL 6 AM EST SUNDAY FOR PAZ074-076.
WIND CHILL ADVISORY UNTIL NOON EST SUNDAY FOR PAZ074-076.
WV...WINTER WEATHER ADVISORY UNTIL 6 AM EST SUNDAY FOR WVZ001>004-
012-021-022.
WINTER STORM WARNING UNTIL 6 AM EST SUNDAY FOR WVZ023-041.
WIND CHILL ADVISORY UNTIL NOON EST SUNDAY FOR WVZ023-041.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
124 PM EST SAT FEB 11 2012
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 446 AM EST SAT FEB 11 2012
LATEST WV IMAGERY AND RUC ANALYSIS REVEALS THE CENTER OF THE POLAR
VORTEX EAST OF HUDSON BAY WITH A MID/UPPER LEVEL TROUGH AXIS
EXTENDING SOUTH INTO THE CENTRAL GREAT LAKES. AT THE SFC...A 1044 MB
ARCTIC HIGH WAS CENTERED OVER THE DAKOTAS. RADAR IMAGERY AND SFC OBS
SHOW WIND PARALLEL LES BANDS FROM EAST OF MQT TO GRAND MARAIS BEING
SUPPORTED BY ENHANCED LOW-LVL CONVERGENCE FROM NW WIND FLOW ACROSS
MUCH OF LAKE SUPERIOR AND THEN LAND BREEZE CIRCULATION OFF OF
ONTARIO CAUSING A NE WIND OVER FAR ERN LAKE SUPERIOR. LES BANDS WITH
RETURNS TO 30 DBZ ARE FAIRLY WELL SPACED APART DUE TO VERY DRY
UPSTREAM AND LARGE SCALE ANTICYCLONIC FLOW ACROSS THE AREA. SURGE OF
MID TO LOW-LVL MOISTURE IN WAA PATTERN MOVING IN FROM NORTH OF LAKE
SUPERIOR IS SHOWING SIGNS OF ENHANCING LES BANDS ACROSS THE LAKE IN
THE PAST HR OR SO. THIS WILL BE SOMETHING TO MONITOR AS THE DAY
PROGRESSES TO SEE IF IT WILL BOOST LES ACCUMS DOWNWIND OF THE LAKE.
TODAY...AS 850-700 MB MOISTURE INCREASES IN A DEVELOPING WAA PATTERN
THERE COULD BE A BRIEF INCREASE IN LES INTENSITY FOR THE ERN
COUNTIES FAVORED BY A WNW/NW WIND. AS I SAID...BELIEVE ANY FLARE UP
IN LES WILL BE SHORT-LIVED SINCE WAA AND RISING 850 MB TEMPS WILL
EVENTUALLY FORCE THE DGZ ABV THE BEST OMEGA/UPWARD MOTION WITHIN THE
CONVECTIVE BOUNDARY LAYER BY THE LATE AFTERNOON/EVENING HRS. LONGER
FETCH ACROSS THE LAKE ALONG WITH MORE FAVORABLE LES PARAMETERS
SUGGEST BEST SNOW ACCUMULATIONS WILL BE OVER THE NE FCST
AREA...WHERE AMOUNTS IN THE 2 TO 4 INCH RANGE ARE POSSIBLE...JUST
BLO ADVISORY CRITERIA. ELSEWHERE...NEAR LAKE SUPERIOR EXPECT LES
AMTS GENERALLY 2 INCHES OR LESS.
TONIGHT...TROF ASSOCIATED WITH POLAR VORTEX E OF HUDSON BAY WILL
BEGIN SHIFTING E OF THE REGION...ALLOWING FOR PROMINENT RIDGING AND
WAA REGIME TO SET UP AND CONTINUE INTO SUN. LES WILL BE ONGOING SAT
EVENING OVER THE E AT LOCATIONS FAVORED BY A WNW/NW WIND OFF LAKE
SUPERIOR. HOWEVER...INVERSION QUICKLY SETTLES DOWN TO 4KFT OR LWR BY
LATE EVENING AND OVERNIGHT. ALSO...CONTINUED WAA WILL KEEP THE
DENDRITIC SNOW GROWTH TEMP ZONE (DGZ) UP ABOVE BEST UPWARD MOTION.
IN GENERAL...MIGHT SEE ANOTHER 1-2...POSSIBLY UP TO 3 INCHES OF SNOW
OVER THE NE FCST AREA SAT NIGHT. OUT W...INVERSION WILL ALREADY BE
SETTLING TO 3KFT OR LWR EARLY IN THE EVENING WITH DGZ ABOVE THE
INVERSION. GIVEN THE LOW INVERSION AND MODERATING AIRMASS...THERE
MAY NOT BE MUCH LEFT OTHER THAN FLURRIES THIS EVENING WITH GRADUAL
CLEARING THEN FOLLOWING DURING THE NIGHT FROM THE W. WITH
CLEARING...MINS COULD DROP NEAR ZERO IN THE TRADITIONAL COLD SPOTS
OVER THE INTERIOR W HALF. NEAR LAKE SUPERIOR WHERE THERE WILL BE
BETTER MIXING AND MODERATION FROM ONSHORE NW FLOW TO KEEP MIN TEMPS
IN THE TEENS.
SUNDAY...LINGERING LIGHT LES/FLURRIES OVER THE NE FCST AREA WILL END
IN THE MORNING AS THE INVERSION CONTINUES TO LWR AND MORE
IMPORTANTLY TEMPS AT INVERSION BASE RISE ABOVE -10C. AWAY FROM
DIMINISHING LIGHT LES E...IT SHOULD TURN OUT TO BE A MAINLY SUNNY
DAY UNDER A DEEP DRY AIR MASS. DRY AIR MASS AND SUNSHINE WORKING ON
THE LWR ALBEDO FORESTED LANDSCAPE OF UPPER MI WILL ASSIST THE WARM
UP...BUT STRONG INVERSION WILL HOLD BACK THE WARMING POTENTIAL OVER
WHAT IT COULD BE. FCST SOUNDINGS SUGGEST MIXING TO JUST ABV 925 MB
LOOK FOR HIGHS GENERALLY IN THE MID/UPPER 20S.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 446 AM EST SAT FEB 11 2012
UPPER TROUGH WILL BE ROTATING E OF THE AREA AT THE START OF THE LONG
TERM PERIOD...LEADING TO THE AREA BEING BETWEEN THE SPLIT FLOW OF
THE NRN STREAM RIDGE OVER THE CANADIAN PRAIRIES AND THE SRN STREAM
RUNNING ACROSS THE SRN FOURTH OF THE CONUS. THIS WILL KEEP THE AREA
UNDER QUIET WEATHER TO START THE PERIOD WITH A HIGH PRESSURE RIDGE
PUSHING OVER THE WRN CWA SUN NIGHT AND MON...WHILE BROAD H850-700
WAA INTENSIFIES OVER STATIONARY FRONT OVER SE ONTARIO.
SUN NIGHT...EXPECT A MOSTLY CLEAR NIGHT WITH THE HIGH PRESSURE RIDGE
PUSHING OVER THE AREA. LOWS WILL DEPEND ON HOW QUICKLY WINDS CAN
DECOUPLE ON MON NIGHT...AS GRADIENT BETWEEN STATIONARY FRONT AND
APPROACHING SFC RIDGE TRIES TO KEEP WINDS UP. BEST CHANCE FOR LIGHT
WINDS WILL BE CLOSER TO THE SFC RIDGE OVER THE SW HALF OF THE
CWA...WHERE PWAT VALUES FALL TO 40 PERCENT OF NORMAL. HAVE TRENDED
TOWARDS THE LOW END OF GUIDANCE...BUT NOT QUITE AS COLD AS IF THE
WAS HIGHER CONF FOR LIGHT WINDS.
MON...AREA WILL BE BETWEEN SFC TROUGH IN SE ONTARIO AND H500
SHORTWAVE AND ASSOCIATED HEIGHT FALLS MOVING THROUGH THE MID MISS
VALLEY AND APPROACHING THE LOWER GREAT LKS MON NIGHT. EXPECT A
MOSTLY SUNNY DAY FOR MUCH OF THE AREA...ALTHOUGH CLOUDS WILL ATTEMPT
TO PUSH ACROSS THE WI BORDER LATE IN THE AFTN WITH MOISTURE
INCREASING AHEAD OF THE SHORTWAVE. HIGHS WILL DEPEND ON AMNT OF
MIXING. MODELS INDICATING MIXING UP TO H900...WHICH WOULD PRODUCE
HIGHS OF 30-35. WITH ABUNDANT SUNSHINE TO START THE DAY...FELT TEMPS
WILL WARM UP QUICKLY AND ONLY MADE A DEGREE OR TWO ADJUSTMENT UP TO
GOING HIGHS.
MODELS CONSISTENT IN H850-650 MOISTURE MOVING INTO THE SRN HALF OF
THE AREA MON NIGHT AS THE SHORTWAVE MOVES SOUTH OF THE CWA. BUT WITH
LACK OF ISENTROPIC ASCENT...WAA...AND MAIN FORCING S OF THE CWA WITH
H500 HEIGHT FALLS...THINK PCPN CHANCES ARE FAIRLY LIMITED.
THEREFORE...HAVE JUST A SLIGHT CHANCE OVER THE SCNTRL CWA AND
CHANCES BRUSHING THE CITY OF MENOMINEE.
DAYS 4 THROUGH 7 /TUES THROUGH FRIDAY/...
SRN STREAM TROUGH WILL BEGIN TO DIG OVER THE SW CONUS ON
TUES...ALLOWING RIDGING TO DEVELOP OVER THE SRN/CNTRL PLAINS AND
CONTINUE INTO WED. MEANWHILE...TROUGH WILL START TO AMPLIFY OVER THE
CANADIAN ROCKIES IN THE NRN STREAM ON TUES AND ATTEMPT TO MERGE WITH
THE SRN STREAM WED NIGHT INTO THURS. THESE SITUATIONS TEND TO BE
DIFFICULT FOR MODELS...BUT 00Z GFS/ECMWF/GEM AND ASSOCIATED ENS
MEANS HANDLE THE LARGE SCALE FEATURES SIMILARLY BUT DO HAVE
DIFFICULTY WITH THE EMBEDDED SHORTWAVES. THUS...HAVE AVERAGE CONF
FOR MUCH OF THE EXTENDED PERIOD.
INITIAL SYSTEM EXITS THE AREA ON TUES...LEAVING AREA IN WSWRLY LLVL
FLOW AND H850 TEMPS AROUND -8C. THIS PROVIDES LIMITED POTENTIAL FOR
LES AND WILL LIKELY SEE MOSTLY CLOUDY SKIES LINGERING INTO WED WITH
NEXT POTENTIAL SHORTWAVE MOVING THROUGH...ALTHOUGH MODELS HAVE LARGE
DIFFERENCES IN INTENSITY.
NRN/SRN STREAMS LOOK TO PHASE ON THURS. WITH THE MORE DOMINATE SRN
STREAM...EXPECT SFC LOW DEVELOPMENT TO FOLLOW THE SRN STREAM TRACK
THAT WILL LIKELY TAKE IT THROUGH THE OHIO VALLEY OR LOWER GREAT LKS.
THIS WOULD BRUSH THE SE CWA AS BEST FORCING/MOISTURE REMAINS CLOSER
TO THE LOW. 00Z ECMWF DID TREND A LITTLE FARTHER NW WITH THE TRACK
OF THE LOW...SO WILL NEED TO WATCH ON FUTURE SHIFTS.
MODELS BEGIN TO DIVERGE HEADING INTO FRI WITH THE HANDLING OF THE
NRN STREAM FEATURES AND WHERE THE SRN STREAM UPPER TROUGH IS LOCATED
OVER THE SW CONUS. H850 TEMPS AROUND -11C WOULD LEAD TO SOME LES
POTENTIAL UNDER NW WINDS...BUT LLVL MOISTURE OVER THE W MAY BE
LIMITED. THEREFORE...ONLY MENTIONED CHANCE POPS OVER THE ERN AREAS
FAVORED BY NW WINDS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 123 PM EST SAT FEB 11 2012
POCKETS OF CLEARING HAVE DEVELOPED IN THE MORE NW FLOW OFF LAKE
SUPERIOR...AT BOTH IWD AND SAW. THE RESULT IS TEMPORARY SCATTERED
CLOUDS...WHICH CMX REMAINS STUCK IN THE MVFR CEILINGS WITH VIS
DROPPING TO LIFR AT TIMES. THE DEEPER MOISTURE OVER THE LAKE WILL
SLOWLY WEAKEN OVERNIGHT..ALTHROUGH NW WINDS WILL STAY WITH GUSTS IN
THE 20 TO 30KT RANGE OVER THE ENTIRE PERIOD. LLWS WILL LIKELY
DEVELOP AT SAW...GIVEN THE NW WIND DIRECTION DURING THE LATE
EVENING/OVERNIGHT HOURS. OTHERWISE...VFR CEILINGS AND VIS WILL TAKE
HOLD AT ALL 3 SITES BY 06Z SUNDAY AS A RIDGE OF HIGH PRESSURE SLIDES
ACROSS THE REGION.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 446 AM EST SAT FEB 11 2012
NNW WINDS TO 30KT WILL PERSIST WITH AMPLE INSTABILITY IN THE ARCTIC
AIRMASS MOVING OVER THE REGION. NW WINDS APPROACHING GALES TO 35 KT
ARE ALSO POSSIBLE THIS AFTERNOON INTO THIS EVENING OVER ERN LAKE
SUPERIOR. EXPECT HEAVY FREEZING SPRAY ACROSS THE ENTIRE LAKE THROUGH
TONIGHT WITH THE STRONG WINDS AND WAVE ACTION. LOOK FOR HEAVY
FREEZING SPRAY TO END ON SUNDAY AS THE AIRMASS WARMS AND WINDS
GRADUALLY DIMINISH. CONDITIONS WILL QUIET DOWN FOR THE EARLY PART OF
THE WORK WEEK AS A HIGH PRES RIDGE MOVES OVER THE UPPER GREAT LAKES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST /6 AM CST/ SUNDAY
FOR LSZ162-240>251-263>267.
GALE WARNING FROM 5 PM THIS AFTERNOON TO 3 AM EST SUNDAY FOR
LSZ248>250-265-266.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...SRF
AVIATION...KF
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1154 AM CST SAT FEB 11 2012
.SHORT TERM...TONIGHT THROUGH MONDAY NIGHT
249 AM CST SAT FEB 11 2012
MAIN FORECAST CONCERN IS ON PRECIPITATION FOR MONDAY
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS
SHOWED TROUGHING COMING INTO CALIFORNIA...RIDGING FROM ARIZONA INTO
SASKATCHEWAN...AND TROUGHING FROM QUEBEC INTO ILLINOIS. THE FORECAST
AREA LIES IN SUBSIDENCE IN THE WAKE OF THE TROUGHING...PROMOTING A
FEED OF DRIER AIR INTO THE FORECAST AREA. 00Z MPX SOUNDING AS WELL
AS A PRECIPITABLE WATER PLOT OF 00Z RAOB DATA ACROSS THE UPPER
MIDWEST REFLECTIVE OF THE DRY AIR...WITH VALUES AROUND 0.05 OF AN
INCH OR 25 PERCENT OF NORMAL. WITH ALL THE DRY AIR...SKIES ARE
CLEAR. ARCTIC AIR SLOWLY FLOWING IN TOO WITH THE DRY AIR ON A
SUSTAINED 10 TO 15 MPH NORTHWEST WIND. TEMPERATURES HAVE FALLEN INTO
THE SINGLE DIGITS ABOVE ZERO. THE LACK OF SNOW COVER AND PERSISTENT
WIND KEEPING TEMPERATURES FROM FALLING MUCH LOWER. COMBINATION OF
THE WIND AND TEMPERATURES RESULTING IN WIND CHILLS MOSTLY IN THE
SINGLE DIGITS OR TEENS BELOW ZERO. AREA OF HIGH PRESSURE ASSOCIATED
WITH THE SUBSIDENCE FAR OFF TO THE WEST...OVER THE DAKOTAS. NO BIG
CHANGE IN 850MB TEMPS FROM 12Z FRI TO 00Z SATURDAY AT BIS...ABR AND
MPX...ALL SITTING BETWEEN -17 AND -20C. HOWEVER...DVN AND GRB WHICH
WERE ALONG THE ARCTIC FRONT AT 12Z DROPPED 9 TO 11C BY 00Z.
TODAY THROUGH SUNDAY...UPPER RIDGING SEEN OVER ARIZONA AND UTAH IS
FORECAST TO BUILD EAST INTO THE PLAINS AND EVENTUALLY THE UPPER
MISSISSIPPI RIVER VALLEY BY LATE SUNDAY...DUE TO TROUGHING MOVING
INTO THE ROCKIES AND FOUR CORNERS REGION. THE FORECAST AREA WILL
REMAIN ON THE EAST SIDE OF THE UPPER RIDGING...PROMOTING SUBSIDENCE
AND CONTINUED DRY AIR ADVECTION. HOWEVER...THE BUILDING HEIGHTS IN
CONJUNCTION WITH THE LACK OF SNOW COVER AND PLENTY OF SUN SHOULD
HELP THE ARCTIC AIRMASS MODERATE THIS WEEKEND. 850MB TEMPS REFLECT
THE MODERATING...CLIMBING TO AROUND -12C AT 00Z SUNDAY AND -6C AT
00Z MONDAY. THE DRY AIRMASS IN PLACE SHOULD ALSO PROMOTE GOOD
MIXING. GIVEN 850MB TEMPS TODAY...HIGHS ARE ONLY EXPECTED IN THE MID
TEENS TO AROUND 20. THE BLUSTERY NORTHWEST WIND WILL MAKE IT FEEL
COOLER...THOUGH...WITH WIND CHILLS ONLY CLIMBING TO AROUND ZERO.
PLENTY OF WIND ANTICIPATED TONIGHT GIVEN THE SURFACE RIDGE TAKING A
TRACK TO OUR SOUTHWEST. THIS WIND SHOULD KEEP LOWS MOSTLY IN THE
SINGLE DIGITS ABOVE ZERO. ANTICIPATING WE CAN TACK ON ANOTHER 10
DEGREES OF WARMING FOR SUNDAY GIVEN THE 6C JUMP IN 850MB TEMPS.
REGARDING THE WIND CHILL ADVISORY...VERY MARGINAL CONDITIONS AT
BEST. SINCE IT IS ALREADY UP AND WIND CHILLS ARE AT LEAST IN THE
TEENS BELOW ZERO...FIGURE IT IS NOT WORTH CANCELING.
SUNDAY NIGHT THROUGH MONDAY NIGHT...FOCUS TURNS TO THE TROUGHING
OVER THE WESTERN U.S AT 00Z MONDAY. GOOD MODEL AGREEMENT EXISTS FOR
THIS TROUGHING TO CROSS THE PLAINS ON MONDAY...THEN SHEAR APART
MONDAY NIGHT AS IT CROSSES THE FORECAST AREA AND THROUGH THE OHIO
VALLEY. BEST 500MB HEIGHT FALLS FOR THE FORECAST AREA OCCUR MONDAY
AFTERNOON AND EVENING...RANGING FROM 40 TO 70 METERS PER 12 HOURS...
HIGHEST IN THE FAR SOUTHERN SECTIONS OF THE AREA. SO THE DPVA
FORCING IS FAIRLY DECENT. ISENTROPIC LIFT FIELDS...ON THE OTHER
HAND...ARE TERRIBLE WITH BASICALLY VERY LITTLE IF ANY NET ADIABATIC
OMEGA FROM EITHER THE 11.00Z NAM OR GFS. BEST 850 TO 700MB MOISTURE
TRANSPORT ALSO NOT THAT IMPRESSIVE...MOSTLY FOCUSED IN MISSOURI...
ILLINOIS AND ARKANSAS. SO BASICALLY ALL PRECIPITATION PRODUCTION
WILL COME FROM THE 500MB HEIGHT FALLS ACTING ON THE WEAKER MOISTURE
BEING TRANSPORTED UP INTO THE AREA. CERTAINLY GOOD MODEL AGREEMENT
EXISTS OF PRECIPITATION SPREADING SOUTHWEST TO NORTHEAST ACROSS MUCH
OF THE FORECAST AREA ON MONDAY...ESPECIALLY DURING THE AFTERNOON...
WHICH SEEMS REASONABLE. RAISED PRECIPITATION CHANCES UP A LITTLE
MORE FOR THE AFTERNOON...MAINLY ALONG AND SOUTH OF I-90. THINK THE
11.00Z NAM QPF IS A LITTLE TOO HIGH GIVEN LACK OF ISENTROPIC LIFT
AND STRONGER MOISTURE TRANSPORT. STILL...COULD PICK UP ANYWHERE FROM
A HALF INCH TO TWO INCHES OF SNOW OUT OF THE EVENT...HIGHEST ACROSS
THE SOUTH WHERE THE BETTER FORCING IS. PRECIPITATION SHOULD SLOWLY
DIMINISH MONDAY NIGHT AS THE UPPER TROUGHING SHEARS APART...REDUCING
THE DPVA LIFT. REGARDING TEMPERATURES...WITH THE PRECIPITATION AND
CLOUDS TRENDING SLOWER TO MOVE IN FOR SUNDAY NIGHT INTO MONDAY
MORNING...LOWERED TEMPERATURES A FEW DEGREES SUNDAY NIGHT AND STAYED
WITH A NORMAL DIURNAL TREND. POTENTIAL DOES EXIST MONDAY MORNING FOR
A LITTLE SUN NORTH OF I-94...THUS HIGHS ON MONDAY END UP WARMEST
NORTH OF I-94. SOUTHERLY ADVECTION OF WARM AIR AHEAD OF THE TROUGH
SHOULD RESULT IN HIGHS AGAIN IN THE UPPER 20S TO AROUND 30. WITH
PLENTY OF CLOUDS LINGERING MONDAY NIGHT AND LITTLE IN THE WAY OF
COLD ADVECTION...ANTICIPATING TEMPERATURES TO ONLY DROP AROUND 5
DEGREES.
.LONG TERM...TUESDAY THROUGH FRIDAY NIGHT
249 AM CST SAT FEB 11 2012
LONG TERM FORECAST LOOKS A LITTLE MORE UNCERTAIN TODAY...THOUGH THE
FEATURES SEEN YESTERDAY OF A SPLIT FLOW PATTERN REMAIN. THE BIGGEST
UNCERTAINTY IS WEDNESDAY NIGHT AND THURSDAY. DURING THIS PERIOD...
THE NEW 11.00Z ECMWF SUGGESTS TROUGHING COMING OUT OF THE SOUTHWEST
U.S. AND EVENTUALLY PHASING WITH A NORTHERN STREAM SHORTWAVE TROUGH
NEAR THE FORECAST AREA. THE RESULT WOULD PROBABLY BE AN
ADVISORY-TYPE WET SNOW EVENT FOR THE SOUTHEASTERN HALF OF THE
FORECAST AREA. PROBLEM IS...THE ECMWF IS THE ONLY MODEL SHOWING THIS
PHASING POTENTIAL. THE 11.00Z GFS/UKMET KEEP THE TWO SEPARATED WITH
THE SOUTHWESTERN TROUGH EJECTING FARTHER SOUTH. MEANWHILE...THE
11.00Z CANADIAN HAS MORE FOCUS ON THE NORTHERN STREAM FEATURE AND
PRODUCES A FAIRLY AMPLIFIED TROUGH OVER MINNESOTA ON THURSDAY. THE
11.00Z GFS ENSEMBLES DEPICT A SIMILAR AMOUNT OF UNCERTAINTY.
THEREFORE...FOR NOW FOLLOWED A CONSENSUS BLEND FOR PRECIPITATION
CHANCES WHICH END UP 20-40. PLUS...IT IS HARD TO TRUST PHASING THIS
FAR OUT.
OTHERWISE...PRECIPITATION FROM MONDAY NIGHT SHOULD FOR THE MOST PART
END TUESDAY AS THE LINGERING SHORTWAVE TROUGH FALLS APART. THIS
LEAVES DRY CONDITIONS FOR TUESDAY NIGHT AND WEDNESDAY...WHICH SHOULD
ALSO BE ASSOCIATED WITH SOME SMALL 500MB HEIGHT RISES AND A SURFACE
RIDGE OF HIGH PRESSURE. AFTER WHATEVER HAPPENS WITH THE WEDNESDAY
NIGHT THROUGH THURSDAY TIME PERIOD...GOOD AGREEMENT EXISTS OF A
WEST-NORTHWEST FLOW PATTERN HEADING INTO NEXT WEEKEND WITH HARD TO
TIME SHORTWAVES MOVING THROUGH THE FLOW. GIVEN THAT HIGH PRESSURE
SHOULD DOMINATE ACROSS THE SOUTHERN U.S. IN THE WAKE OF THE THURSDAY
SYSTEM...PREVENTING MOISTURE RETURN FROM THE GULF OF MEXICO FOR A
LITTLE WHILE...KEPT CONDITIONS DRY FOR FRIDAY.
ONE THING THAT DOES LOOK CERTAIN FOR THE LONG TERM PERIOD IS
TEMPERATURES TO REMAIN AT OR ABOVE NORMAL. A BRIEF SHOT OF COOL AIR
MAY COME THROUGH ON THURSDAY WITH 850MB TEMPS FALLING TO -6 TO -8C.
STILL...THIS WOULD BE ABOVE NORMAL. STAYED PRETTY MUCH WITH A BLEND
OF ALL GUIDANCE FOR TEMPERATURES AS IT SEEMS REASONABLE AT THIS
POINT.
&&
.AVIATION...THROUGH 18Z SUNDAY
1152 AM CST SAT FEB 11 2012
BRISK NORTHWEST WINDS WILL PERSIST THROUGH THIS AFTERNOON AS THE
AREA REMAINS UNDER A TIGHT PRESSURE GRADIENT. THE WINDS WILL
SUBSIDE THIS EVENING WITH SUNSET. OTHERWISE...LOOK FOR MOSTLY
CLEAR/VFR CONDITIONS THROUGH SUNDAY AS HIGH PRESSURE REMAINS THE
DOMINANT WEATHER FEATURE.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
746 AM CST SAT FEB 11 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...DAS